Posts by Jai Ganesh

Jai Ganesh · This is Cool

2487) Skyscraper

Skyscraper

Gist

A skyscraper is a very tall, multi-story building, typically found in cities, that is supported by a metal framework and often used for offices, hotels, or residences, with modern definitions generally considering buildings over 100 or 150 meters (330-490 ft) as skyscrapers. The term emerged in the late 1880s with early high-rises in the U.S., evolving to describe exceptionally tall structures.

A skyscraper typically has over 40 floors, though the definition has evolved from early buildings of 10-20 stories to today's supertalls that often exceed 100 floors, with no strict minimum, but generally defined by being very tall and continuously habitable. Modern skyscrapers leverage steel frames and elevators, allowing for extreme heights, like the 163-story Burj Khalifa.

Summary

A skyscraper is a tall building with many habitable floors. Most modern sources define skyscrapers as being at least 100 metres (330 ft) or 150 metres (490 ft) in height, though there is no universally accepted definition, other than being very tall high-rise buildings. Skyscrapers may host offices, hotels, residential spaces, and retail spaces. Skyscrapers are a common feature of large cities, often due to a high demand for space and limited availability of land.

One common feature of skyscrapers is having a steel frame that supports curtain walls. These curtain walls either bear on the framework below or are suspended from the framework above, rather than resting on load-bearing walls of conventional construction. Some early skyscrapers have a steel frame that enables the construction of load-bearing walls taller than those made of reinforced concrete. Modern skyscraper walls are not load-bearing, and most skyscrapers are characterized by large surface areas of windows made possible by steel frames and curtain walls. However, skyscrapers can have curtain walls that mimic conventional walls with a small surface area of windows. Modern skyscrapers often have a tubular structure, and are designed to act like a hollow cylinder to resist wind, seismic, and other lateral loads. To appear more slender, allow less wind exposure and transmit more daylight to the ground, many skyscrapers have a design with setbacks, which in some cases is also structurally required.

Skyscrapers first appeared in the United States at the end of the 19th century, especially in the cities of Chicago and New York City. Following a building boom across the western world in the early 20th century, skyscraper development was halted in the 1930s by the Great Depression, and did not resume until the 1950s. A skyscraper boom in the downtowns of many American cities took place during the 1960s to 1980s. Towards the second half of the 20th century, skyscrapers began to be built more frequently outside the United States, particularly in East Asia and Southeast Asia during the 1990s. China has since overtaken the United States as the country with the most skyscrapers. Skyscrapers are an increasingly global phenomenon, and can be found in over 70 countries.

There are over 7 thousand skyscrapers over 150 m (490 ft) in height worldwide, most of which were built in the 21st century. Over three-quarters of skyscrapers taller than 150 m (492 ft) are located in Asia. Eighteen cities in the world have more than 100 skyscrapers that are taller than 150 m (492 ft), most recently Toronto and Singapore in 2025. The city with the most skyscrapers in the world is Hong Kong, with 569 skyscrapers, followed by Shenzhen in China with 444, New York City with 317, and Dubai in the United Arab Emirates with 270. Dubai is home to the tallest skyscraper in the world, the Burj Khalifa.

Details

Skyscraper is a very tall multistoried building. The name first came into use during the 1880s, shortly after the first skyscrapers were built, in the United States. The development of skyscrapers came as a result of the coincidence of several technological and social developments. The term skyscraper originally applied to buildings of 10 to 20 stories, but by the late 20th century the term was used to describe high-rise buildings of unusual height, generally greater than 40 or 50 stories.

The increase in urban commerce in the United States in the second half of the 19th century augmented the need for city business space, and the installation of the first safe passenger elevator (in the Haughwout Department Store, New York City) in 1857 made practical the erection of buildings more than four or five stories tall. Although the earliest skyscrapers rested on extremely thick masonry walls at the ground level, architects soon turned to the use of a cast-iron and wrought-iron framework to support the weight of the upper floors, allowing for more floor space on the lower stories. James Bogardus built the Cast Iron Building (1848, New York City) with a rigid frame of iron providing the main support for upper-floor and roof loads.

It was, however, the refinement of the Bessemer process, first used in the United States in the 1860s, that allowed for the major advance in skyscraper construction. As steel is stronger and lighter in weight than iron, the use of a steel frame made possible the construction of truly tall buildings. William Le Baron Jenney’s 10-story Home Insurance Company Building (1884–85) in Chicago was the first to use steel-girder construction. Jenney’s skyscrapers also first employed the curtain wall, an outer covering of masonry or other material that bears only its own weight and is affixed to and supported by the steel skeleton. Structurally, skyscrapers consist of a substructure of piers beneath the ground, a superstructure of columns and girders above the ground, and a curtain wall hung on the girders.

As the population density of urban areas has increased, so has the need for buildings that rise rather than spread. The skyscraper, which was originally a form of commercial architecture, has increasingly been used for residential purposes as well.

The design and decoration of skyscrapers have passed through several stages. Jenney and his protégé Louis Sullivan styled their buildings to accentuate verticality, with delineated columns rising from base to cornice. There was, however, some retention of, and regression to, earlier styles as well. As part of the Neoclassical revival, for instance, skyscrapers such as those designed by the firm of McKim, Mead, and White were modeled after Classical Greek columns. The Metropolitan Life Insurance Building in New York City (1909) was modeled by Napoleon Le Brun after the Campanile of St. Mark’s in Venice, and the Woolworth Building (1913), by Cass Gilbert, is a prime example of neo-Gothic decoration. Even the Art Deco carvings on such towers as the Chrysler Building (1930), the Empire State Building (1931), and the RCA Building (1931) in New York City, which were then considered as modern as the new technology, are now viewed as more related to the old ornate decorations than to truly modern lines.

The International Style with its total simplicity seemed ideally suited to skyscraper design, and, during the decades following World War II, it dominated the field, notable early examples being the Seagram Building (1958) in New York City and the Lake Shore Drive Apartments (1951) in Chicago. The stark verticality and glass curtain walls of this style became a hallmark of ultramodern urban life in many countries. During the 1970s, however, attempts were made to redefine the human element in urban architecture. Zoning ordinances encouraged the incorporation of plazas and parks into and around the bases of even the tallest skyscrapers, just as zoning laws in the first decades of the 20th century were passed to prevent city streets from becoming sunless canyons and led to the shorter, stepped skyscraper. Office towers, such as those of the World Trade Center (1972) in New York City and the Sears Tower (1973; now called Willis Tower) in Chicago, continued to be built, but most of them, such as the Citicorp Center (1978) in New York City, featured lively and innovative space for shopping and entertainment at street level.

Another factor influencing skyscraper design and construction in the late 20th and early 21st centuries was the need for energy conservation. Earlier, sealed windows that made necessary continuous forced-air circulation or cooling, for instance, gave way in mid-rise buildings to operable windows and glass walls that were tinted to reflect the sun’s rays. Also, perhaps in reaction to the austerity of the International Style, the 1980s saw the beginnings of a return to more classical ornamentation, such as that of Philip Johnson’s AT&T Building (1984) in New York City.

Additional Information

A skyscraper is a very tall high-rise building, usually more than 152 metres (500 feet) in height. Most skyscrapers are built in urban areas such as cities, and they are very common in the central business district (also called downtown) areas of many large cities including New York City, Chicago, London, Paris, Sydney, Beijing, Berlin, Toronto, Moscow, Hong Kong and Tokyo. Skyscrapers are common in downtown districts where it's more economical to build up instead of out.

History

Originally, the word skyscraper meant a tall sail on a sailing ship. Over time, the word's meaning has changed, and today it means a tall building. Until the nineteenth century, buildings taller than six stories tall were not common. Tall buildings made of weak materials would fall down. In addition, people did not like walking up many steps and running water could only be brought up to fifty feet (15m) high.

Better technology helped make skyscrapers more common. Stronger building materials such as steel and reinforced concrete were developed, so stronger buildings could be made. Water pumps brought water up to heights above fifty feet.

The first building to be considered a skyscraper, the Home Insurance Building, was built in Chicago, Illinois in the United States, and was designed by William LeBaron Jenney. The building, ten stories high, was built from 1884 to 1885. It was destroyed in 1931 because they wanted to build another building in its previous place.

In the same year the Home Insurance Building was destroyed, one of the oldest and most famous skyscrapers, the Empire State Building, opened in New York City. Later in the 20th century, people started building skyscrapers in cities that did not have many tall buildings in the past. In 1973, the then-called Sears Tower in Chicago was finished and became the world's tallest building until the late 1990s. It took the record from the World Trade Center in New York City, which opened in 1970 but was destroyed in the September 11, 2001 attacks.

Many taller buildings have been built since then, including Taipei 101 in Taipei. This building was the world's tallest from 2004 until 2008, when the Burj Khalifa in Dubai opened. Burj Khalifa is at this time the tallest building and man-made structure ever made, but the Jeddah Tower in Jeddah, which is still being built, will be even taller.

Jai Ganesh · This is Cool

Neuron

Gist

A neuron, or nerve cell, is the fundamental unit of the nervous system, specialized to transmit information via electrical and chemical signals, enabling functions from thinking and feeling to movement, and forms the basis of the brain and nerves throughout the body. Structurally, a neuron typically consists of a cell body (soma), dendrites that receive signals, and an axon that transmits signals to other cells.

The basic functions of neurons can be summarized into four main tasks: receiving signals, integrating these signals/generating signals and transmitting the signals to target cells and organs. These functions reflect in the microanatomy of the neuron.

Summary

A neuron (American English), neurone (British English), or nerve cell, is an excitable cell that fires electric signals called action potentials across a neural network in the nervous system, mainly in the central nervous system and help to receive and conduct impulses. Neurons communicate with other cells via synapses, which are specialized connections that commonly use minute amounts of chemical neurotransmitters to pass the electric signal from the presynaptic neuron to the target cell through the synaptic gap.

Neurons are the main components of nervous tissue in all animals except sponges and placozoans. Plants and fungi do not have nerve cells. Molecular evidence suggests that the ability to generate electric signals first appeared in evolution some 700 to 800 million years ago, during the Tonian period. Predecessors of neurons were the peptidergic secretory cells. They eventually gained new gene modules which enabled cells to create post-synaptic scaffolds and ion channels that generate fast electrical signals. The ability to generate electric signals was a key innovation in the evolution of the nervous system.

Neurons are typically classified into three types based on their function. Sensory neurons respond to stimuli such as touch, sound, or light that affect the cells of the sensory organs, and they send signals to the spinal cord and then to the sensorial area in the brain. Motor neurons receive signals from the brain and spinal cord to control everything from muscle contractions to glandular output. Interneurons connect neurons to other neurons within the same region of the brain or spinal cord. When multiple neurons are functionally connected together, they form what is called a neural circuit.

A neuron contains all the structures of other cells such as a nucleus, mitochondria, and Golgi bodies but has additional unique structures such as an axon, and dendrites. The soma or cell body, is a compact structure, and the axon and dendrites are filaments extruding from the soma. Dendrites typically branch profusely and extend a few hundred micrometers from the soma. The axon leaves the soma at a swelling called the axon hillock and travels for as far as 1 meter in humans or more in other species. It branches but usually maintains a constant diameter. At the farthest tip of the axon's branches are axon terminals, where the neuron can transmit a signal across the synapse to another cell. Neurons may lack dendrites or have no axons. The term neurite is used to describe either a dendrite or an axon, particularly when the cell is undifferentiated.

Most neurons receive signals via the dendrites and soma and send out signals down the axon. At the majority of synapses, signals cross from the axon of one neuron to the dendrite of another. However, synapses can connect an axon to another axon or a dendrite to another dendrite. The signaling process is partly electrical and partly chemical. Neurons are electrically excitable, due to the maintenance of voltage gradients across their membranes. If the voltage changes by a large enough amount over a short interval, the neuron generates an all-or-nothing electrochemical pulse called an action potential. This potential travels rapidly along the axon and activates synaptic connections as it reaches them. Synaptic signals may be excitatory or inhibitory, increasing or reducing the net voltage that reaches the soma.

In most cases, neurons are generated by neural stem cells during brain development and childhood. Neurogenesis largely ceases during adulthood in most areas of the brain.

Details

The nervous system consists of two main cell types, neurons and supporting glial cells. The neuron (or nerve cell) is the functional unit of both the central nervous system (CNS) and the peripheral nervous system (PNS). The basic functions of neurons can be summarized into four main tasks: receiving signals, integrating these signals/generating signals and transmitting the signals to target cells and organs. These functions reflect in the microanatomy of the neuron. As such, neurons typically consist of four main functional parts which include the:

* Receptive part (dendrites), which receive and conduct electrical signals toward the cell body
* Integrative part (usually equated with the cell body/soma), containing the nucleus and most of the cell's organelles, acting as the trophic center of the entire neuron. More importantly, it is here where inputs are processed and integrated to determine whether an electrical impulse (action potential) will be generated.
* Conductive part (axon), which conducts electrical impulses away from the cell body.
* Transmissive part (axon terminals), where axons communicate with other neurons or effectors (target structures which respond to nerve impulses)

Neurons are categorized into different types based on their unique morphologies and functions. This article will focus on the structure and physiology of a typical multipolar neuron, the primary neuronal type found in the CNS, and explore its parts and functions in greater detail.

Neurons: Structure and types:

Neuron structure

Description: Spherical or polygonal central component of a neuron
Function: Integration and signal processing, protein synthesis, metabolic activities
Components: Nucleus (DNA), cytoplasmic organelles (endoplasmic reticulum (smooth and rough), Golgi apparatus, microtubules, mitochondria, lysosomes), axon hillock

Axon hillock

Description: Specialized, cone-shaped region of the cell body which forms the initial segment of the axon
Function: Site for initiation of action potentials (with initial segment of axon)
Components:
- Devoid of large cytoplasmic organelles (Nissl bodies and Golgi apparatus),
- Contains high density of voltage-gated sodium channels

Dendrites

Description: Tree-like, short, tapering processes of varying shape
Function: Reception of synaptic signals and translation into electrical events
Components: Similar to the cell body, neurotransmitter receptors, dendritic shaft, dendritic spines

Axon (nerve fiber)

Description: Single long process arising from the axon hillock
Function: Conduction of electrical impulses away from the cell body
Components:
- Axolemma (cell membrane), axoplasm (cytoplasm), myelin sheath, myelin sheath gaps (nodes of Ranvier), terminal arborizations, terminal boutons, microtubules, intermediate filaments
- Devoid of endoplasmic reticulum and ribosomes

Cell body

The cell body of a neuron, also known as the soma, is typically located at the center of the dendritic tree in multipolar neurons. It is spherical or polygonal in shape and relatively small, making up one-tenth of the total cell volume.

The functionality of the neuron is highly dependent on its cell body as it houses the nucleus, which contains the genetic material (DNA) of the cell as well as various cytoplasmic organelles. These organelles include the endoplasmic reticulum (both smooth and rough), which clusters with free ribosomes to form what is known as chromatophilic substances ( Nissl bodies) and are involved in the protein synthesis of enzymes, receptors, ion channels and other structural components. Additionally, the cell body contains the Golgi apparatus and microtubules, involved in the packaging and transport of proteins; mitochondria, involved in energy production; and lysosomes involved in the waste management of the cell.

The axon hillock refers to an anatomically and functionally distinct area of the cell body which serves as the origin of the axon. It is cone-shaped and devoid of large cytoplasmic organelles such as chromatophilic substance (Nissl bodies) and Golgi apparatus. The axon hillock contains a high density of voltage-gated sodium channels, allowing it to serve as a critical site for determining whether or not the sum of all incoming signals warrants the propagation of an action potential. It also supports neuron polarity by separating the receptive/integrative parts from the conductive/transmissive parts, providing directionality in the flow of information from the dendrites to the cell body, axon and axon terminals.

The region of the axon laying between the axon hillock and the beginning of the myelin sheath is termed the initial segment. This is the actual site of action potential generation, although more recent research states that both the initial segment and axon hillock are capable of action potential generation.

Dendrites

Dendrites are tree-like processes extending from the cell body of the neuron and contain organelles similar to those in the cell body. The highly branched structure of dendrites provides an increased surface area for receiving information from other neurons at specialized areas of contact called synapses. Dendrites primarily consist of dendritic shafts, which serve as the main structural branches.

These are lined with numerous tiny protrusions called dendritic spines, which serve as sites for the initial processing of synaptic signals via membrane embedded neurotransmitter receptors; they translate the chemical messages received into electrical events, which travel down the dendrites. There are approximately ten trillion of these structures present across all dendrites of neurons in the human cerebral cortex (for 16-20 billion neurons), therefore they greatly increase the area available for synaptic events.

Axon

The axon of a neuron is also known as a nerve fiber. The membrane of an axon is known as the axolemma, while the cytoplasm is also referred to as axoplasm. Bundles of axons in the CNS form a tract, while in the PNS, they are referred to as fascicles (which, when bound together with connective tissue, form nerves). Axons originate from the axon hillock and conduct electrical impulses, in the form of action potentials, away from the cell body through a process of sequential depolarization and repolarization. Unlike dendrites that form a complex network with many tapering branches, the axon of a neuron is usually a single, long process that can extend for a considerable distance before it branches and terminates. The length of axons varies and can sometimes exceed a meter, such as in some peripheral nerves like the sciatic nerve, which extends from the spinal cord to the feet.

Axons typically terminate as fine branches called terminal arborizations; each of which is capped with a terminal bouton. These specialized structures contain synaptic vesicles that store neurotransmitters to be released into the synaptic cleft (a small gap at a synapse between neurons where nerve impulses are transmitted by a neurotransmitter) when an action potential reaches the axon terminal.

Axons can be enveloped in an insulating layer of lipids and proteins called the myelin sheath. This sheath protects the axon and prevents the loss of electrical charge (ions) during the transmission of action potentials along the neuron, increasing the speed of impulse transmission. The myelin sheath is formed by specific types of glial cells, namely oligodendrocytes in the CNS and Schwann cells (neurolemmocytes) in the PNS. The myelination of PNS axons involves many Schwann cells, each of which participates in the formation of the myelin sheath of a single axon, by wrapping around it multiple times. Not all axons are covered by myelin. In the PNS, multiple nonmyelinated axons can go through a single Schwann cell, without myelin sheath production. In contrast, an oligodendrocyte can myelinate multiple axons in the CNS, due to its arm-like processes twisting around them.

The outermost nucleated cytoplasmic layer of Schwann cells overlying the myelin sheath is called the neurolemma. This structural characteristic aids in the regeneration of damaged peripheral axons when the corresponding cell body remains intact. In contrast, CNS neurons, which lack a neurolemma, exhibit limited regenerative capacity.

Nerve fibers are classified into groups, based on their myelination; group A neurons are heavily myelinated, group B are moderately myelinated, and group C are nonmyelinated. Along myelinated axons, evenly distributed gaps known as myelin sheath gaps (commonly referred to as nodes of Ranvier) allow electrical impulses to jump from node to node. This propagation pattern is referred to as saltatory conduction. Myelin sheath gapsare more numerous in axons of the PNS compared to those of the CNS.

Since axons lack endoplasmic reticulum and ribosomes, proteins and organelles needed for its growth are synthesized in the cell body and then transported to the axon via axonal transport. This is facilitated by microtubules and intermediate filaments that provide cytoskeletal "tracks" for transportation. The microtubule arrangements overlap, providing routes for simultaneous transport of different materials to and from the cell body.

Additional Information

Neurons (also called neurones or nerve cells) are the fundamental units of the brain and nervous system, the cells responsible for receiving sensory input from the external world, for sending motor commands to our muscles, and for transforming and relaying the electrical signals at every step in between. More than that, their interactions define who we are as people. Having said that, our roughly 100 billion neurons do interact closely with other cell types, broadly classified as glia (these may actually outnumber neurons, although it’s not really known).

The creation of new neurons in the brain is called neurogenesis, and this can happen even in adults.

What does a neuron look like?

A useful analogy is to think of a neuron as a tree. A neuron has three main parts: dendrites, an axon, and a cell body or soma (see image below), which can be represented as the branches, roots and trunk of a tree, respectively. A dendrite (tree branch) is where a neuron receives input from other cells. Dendrites branch as they move towards their tips, just like tree branches do, and they even have leaf-like structures on them called spines.

The axon (tree roots) is the output structure of the neuron; when a neuron wants to talk to another neuron, it sends an electrical message called an action potential throughout the entire axon. The soma (tree trunk) is where the nucleus lies, where the neuron’s DNA is housed, and where proteins are made to be transported throughout the axon and dendrites.

There are different types of neurons, both in the brain and the spinal cord. They are generally divided according to where they orginate, where they project to and which neurotransmitters they use.

Concepts and definitions

Axon – The long, thin structure in which action potentials are generated; the transmitting part of the neuron. After initiation, action potentials travel down axons to cause release of neurotransmitter.

Dendrite – The receiving part of the neuron. Dendrites receive synaptic inputs from axons, with the sum total of dendritic inputs determining whether the neuron will fire an action potential.

Spine – The small protrusions found on dendrites that are, for many synapses, the postsynaptic contact site.

Action potential – Brief electrical event typically generated in the axon that signals the neuron as 'active'. An action potential travels the length of the axon and causes release of neurotransmitter into the synapse. The action potential and consequent transmitter release allow the neuron to communicate with other neurons.

Jai Ganesh · Dark Discussions at Cafe Infinity

2425) Severo Ochoa

Gist:

Work

The substances known as DNA and RNA bear organisms' genetic code and also determine their vital processes. Severo Ochoa investigated how DNA and RNA are formed and which enzymes control this process. By studying bacteria, Ochoa and Marianne Grunberg-Manago discovered an enzyme in 1955 that can join nucleotides–the building blocks of RNA and DNA–together. Initially, it was thought that this enzyme assembled RNA based on information contained in DNA. This was later proven to be incorrect, although the enzyme proved to have other important functions nonetheless.

Summary

Severo Ochoa (born Sept. 24, 1905, Luarca, Spain—died Nov. 1, 1993, Madrid) was a biochemist and molecular biologist who received (with the American biochemist Arthur Kornberg) the 1959 Nobel Prize for Physiology or Medicine for his discovery of an enzyme in bacteria that enabled him to synthesize ribonucleic acid (RNA), a substance of central importance to the synthesis of proteins by the cell.

Ochoa was educated at the University of Madrid, where he received his M.D. in 1929. He then spent two years studying the biochemistry and physiology of muscle under the German biochemist Otto Meyerhof at the University of Heidelberg. He also served as head of the physiology division, Institute for Medical Research, at the University of Madrid (1935). He investigated the function in the body of thiamine (vitamin B1) at the University of Oxford (1938–41) and became a research associate in medicine (1942) and professor of pharmacology (1946) at New York University, New York City, where he became professor of biochemistry and chairman of the department in 1954. From 1974 to 1985 he was associated with the Roche Institute of Molecular Biology; thereafter he taught at the Autonomous University of Madrid. Ochoa became a U.S. citizen in 1956.

Ochoa made the discovery for which he received the Nobel Prize in 1955, while conducting research on high-energy phosphates. He named the enzyme he discovered polynucleotide phosphorylase. It was subsequently determined that the enzyme’s function is to degrade RNA, not synthesize it; under test-tube conditions, however, it runs its natural reaction in reverse. The enzyme has been singularly valuable in enabling scientists to understand and re-create the process whereby the hereditary information contained in genes is translated, through RNA intermediaries, into enzymes that determine the functions and character of each cell.

Details

Severo Ochoa de Albornoz (24 September 1905 – 1 November 1993) was a Spanish physician and biochemist, and winner of the 1959 Nobel Prize in Physiology or Medicine together with Arthur Kornberg for their discovery of "the mechanisms in the biological synthesis of deoxyribonucleic acid (DNA)".

Education and early life

Ochoa was born in Luarca (Asturias), Spain. His father was Severo Manuel Ochoa (who he was named after), a lawyer and businessman, and his mother was Carmen de Albornoz. Ochoa was the nephew of Álvaro de Albornoz (President of the Second Spanish Republic in exile and former Foreign Minister), and a cousin of the poet and critic Aurora de Albornoz. His father died when Ochoa was seven, and he and his mother moved to Málaga, where he attended elementary school through high school. His interest in biology was stimulated by the publications of the Spanish neurologist and Nobel laureate Santiago Ramón y Cajal. In 1923, he went to the University of Madrid Medical School, where he hoped to work with Ramón y Cajal, but Ramón y Cajal retired. He studied with father Pedro Arrupe, and Juan Negrín was his teacher:

Negrin opened wide, fascinating vistas to my imagination, not only through his lectures and laboratory teaching, but through his advice, encouragement, and stimulation to read scientific monographs and textbooks in languages other than Spanish.

Negrín encouraged Ochoa and another student, José Valdecasas, to isolate creatinine from urine. The two students succeeded and also developed a method to measure small levels of muscle creatinine. Ochoa spent the summer of 1927 at University of Glasgow working with D. Noel Paton on creatine metabolism and improving his English skills. He also refined the assay procedure further and upon returning to Spain he and Valdecasas submitted a paper describing the work to the Journal of Biological Chemistry, where it was rapidly accepted, marking the beginning of Ochoa's biochemistry career.

Ochoa completed his undergraduate medical degree in the summer of 1929 and decide to go abroad again to gain further research experience. His creatine and creatinine work led to an invitation to join Otto Meyerhof's laboratory at the Kaiser Wilhelm Institute for Biology in Berlin-Dahlem in 1929. At that time the institute was a "hot bed" of the rapidly evolving discipline of biochemistry, and thus Ochoa had the experience of meeting and interacting with scientists such as Otto Heinrich Warburg, Carl Neuberg, Einar Lundsgaard, and Fritz Lipmann in addition to Meyerhof who had received the Nobel Prize in Physiology and Medicine less than a decade earlier.

In 1930 Ochoa returned to Madrid to complete research for his MD thesis, which he defended that year. In 1931, a newly minted MD, he married Carmen García Cobián. They did not have any children. He then began postdoctoral study at the National Institute for Medical Research in London, where he worked with Henry Hallett Dale. His London research involved the enzyme glyoxalase and was an important departure in Ochoa's career in two respects. First, the work marked the beginning of Ochoa's lifelong interest in enzymes. Second, the project was at the cutting edge of the rapidly evolving study of intermediary metabolism.

Career and research

In 1933 the Ochoas returned to Madrid where he began to study glycolysis in heart muscle. Within two years, he was offered the directorship of the Physiology Section in a newly created Institute for Medical Research at the University of Madrid Medical School. Unfortunately the appointment was made just as the Spanish Civil War erupted. Ochoa decided that trying to perform research in such an environment would destroy forever his "chances of becoming a scientist." Thus, "after much thought, my wife and I decided to leave Spain." In September 1936 they began what he later called the "wander years" as they traveled from Spain to Germany, to England, and ultimately to the United States within a span of four years.

Ochoa left Spain and returned to Meyerhof's Kaiser Wilhelm Institute for Biology now relocated in Heidelberg, where Ochoa found a profoundly changed research focus. During his 1930 visit the laboratory work was "classical physiology," which Ochoa described as "one could see muscles twitching everywhere". By 1936 Meyerhof's laboratory had become one of the world's foremost biochemical facilities focused on processes such as glycolysis and fermentation. Rather than studying muscles "twitch," the lab was now purifying and characterizing the enzymes involved in muscle action and those involved in yeast fermentation.

From then until 1938, he held many positions and worked with many people at many places. For example, Otto Meyerhof appointed him Guest Research Assistant at the Kaiser Wilhelm Institute for Medical Research in Heidelberg for one year. From 1938 until 1941 he was Demonstrator and Nuffield Research Assistant at the University of Oxford.

Ochoa continued research on protein synthesis and replication of RNA viruses until 1985, when he returned to now democratic Spain where he was a science advisor. Ochoa was also a recipient of U.S. National Medal of Science in 1978.

Severo Ochoa died in Madrid, Spain on 1 November 1993. Carmen García Cobián had died in 1986.

Long after his death, Spanish actress Sara Montiel claimed that she and Severo Ochoa were involved in a romantic relationship in the 1950s, as stated in an interview in Spanish newspaper El País: "The great love of my life was Severo Ochoa. But it was an impossible love. Clandestine. He was married, and besides, him doing research and me doing films wasn't a good match."

Legacy

A research center that was planned in the 1970s was opened in 1975 (CBM) in the Autonomous University of Madrid (UAM). After his death, it was named the Centro de Biología Molecular Severo Ochoa.

In Leganés, Madrid, a hospital bears his name, as does the Madrid Metro station serving it, Hospital Severo Ochoa.

The asteroid 117435 Severochoa is also named in his honor.

In 2003, the Spanish General Post Office (Correos) issued a €0,76 postage stamp honoring Ochoa, as one of a pair featuring Spanish medical Nobel Prize winners[14] alongside Santiago Ramón y Cajal.

In June 2011, the United States Postal Service issued a stamp honoring him, as part of the American Scientists collection, along with Melvin Calvin, Asa Gray, and Maria Goeppert-Mayer. This was the third volume in the series.

The main road in to the tourist resort Benidorm is named Avenida Dr. Severo Ochoa in his honor.

Jai Ganesh · Science HQ

Bowman's Capsule

Gist

The glomerular capsule, also known as Bowman's capsule, is the blind expanded end of a renal tubule. It is a double layered epithelial capsule surrounding the glomerulus. The glomerular capsule together with the glomerulus are termed the renal corpuscle, the site of blood filtration within the kidneys.

The fluid entering Bowman's capsule is called glomerular filtrate, which consists of plasma from blood minus large proteins and cells that cannot pass through the filtration barrier.

Bowman's capsule looks like a pouch, sac or cup. You can only see it under a microscope. Bowman's capsule contains fluid like blood plasma, but with no red or white blood cells or platelets.

Bowman's capsule surrounds the glomerular capillary loops and participates in the filtration of blood from the glomerular capillaries. Bowman's capsule also has a structural function and creates a urinary space through which filtrate can enter the nephron and pass to the proximal convoluted tubule.

Summary

Bowman's capsule (or the Bowman capsule, capsula glomeruli, or glomerular capsule) is a cup-like sac at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac. Fluids from blood in the glomerulus are collected in the Bowman's capsule.

Structure

Outside the capsule, there are two poles:

* The vascular pole is the side with the afferent arteriole and efferent arteriole.
* The tubular pole, is the side with the proximal convoluted tubule.

Inside the capsule, the layers are as follows, from outside to inside:

* Parietal layer—A single layer of simple squamous epithelium. Does not function in filtration.
* Bowman's space (or "urinary space", or "capsular space")—Between the visceral and parietal layers, into which the filtrate enters after passing through the filtration slits.
* Visceral layer—Lies just above the thickened glomerular basement membrane and is made of podocytes. Beneath the visceral layer lie the glomerular capillaries.
* Filtration barrier—The filtration barrier is composed of the fenestrated endothelium of the glomerular capillaries, the fused basal lamina of the endothelial cells and podocytes, and the filtration slits of the podocytes. The barrier permits the passage of water, ions, and small molecules from the bloodstream into the Bowman's space. The barrier prevents the passage of large and/or negatively charged proteins (such as albumin). The basal lamina of the filtration barrier is composed of three layers. The first layer is the lamina rara externa, adjacent to the podocyte processes. The second layer is the lamina rara interna, adjacent to the endothelial cells. The final layer is the lamina densa which is a darker central zone of the basal lamina. It consists of the meshwork of type IV collagen and laminin which act as a selective macromolecular filter.

Function

The process of filtration of the blood in the Bowman's capsule is ultrafiltration, and the normal rate of filtration is 125 ml/min, equivalent to 80 times the daily blood volume. It is a major site for blood filtration (including glomerulus).

Any proteins under roughly 30 kilodaltons can pass freely through the membrane, although there is some extra hindrance for negatively charged molecules due to the negative charge of the basement membrane and the podocytes.

Any small molecules such as water, glucose, salt (NaCl), amino acids, and urea pass freely into Bowman's space, but cells, platelets and large proteins do not.

As a result, the filtrate leaving the Bowman's capsule is very similar to blood plasma (filtrate or glomerular filtrate is composed of blood plasma minus plasma protein i.e. it contains all the components of blood plasma except the proteins) in composition as it passes into the proximal convoluted tubule.

Details

Bowman’s capsule is part of a nephron, a filter in your kidney. One million nephrons in each kidney clean your blood. A Bowman’s capsule in each nephron plays a part in the filtering process. After filtering, nutrients stay in your blood, and waste goes out through urine.

Overview

Bowman’s capsule surrounds blood vessels in each nephron that filters blood in your kidneys.

What is Bowman’s capsule?

Bowman’s capsule is a part of each filtering unit (nephron) in your kidney. You have about 1 million nephrons that filter blood in each of your two kidneys. Kidneys clean blood and return it to your body.

Every nephron has a glomerulus. A two-walled pouch, Bowman’s capsule covers the glomerulus. This group of tiny blood vessels is the starting point for filtering waste products out of your blood. Bowman’s capsule and the glomerulus make up the renal corpuscle.

You may hear other names for Bowman’s capsule, like:

* Glomerular capsule
* Malpighian capsule
* Renal corpuscular capsule

The space in between the walls (layers) of Bowman’s capsule is called Bowman’s space. You may hear healthcare providers refer to Bowman’s space as:

* Glomerular capsule space
* Filtration space
* Urinary space

Function:

What is the function of the Bowman’s capsule in the kidney?

The function of Bowman’s capsule is to help the glomerulus filter blood. Small molecules from your blood pass freely into Bowman’s space. Cells and large proteins stay in your blood.

The glomerular capsule also protects cells called podocytes by keeping white blood cells from getting in. White blood cells can’t pass through Bowman’s capsule. Podocytes in a kidney capsule have pedicels that manage what stays and what goes. Finger-like pedicels link together like they’re holding hands. The way they join creates slits that only let certain things go through. When you’re healthy, protein and cell content can’t get through.

The small molecules then pass through tubes in your kidney. Your kidney regulates which molecules your blood absorbs and which leave your body in pee (urine).

Waste materials go out of your body as urine through tubules (tiny tubes). The blood pressure in the glomerulus helps move the blood along. As the fluids leave, water and nutrients go back into your blood.

Two arterioles go into the Bowman’s capsule. One brings blood into the glomerulus. The other lets blood out.

Anatomy:

Where is Bowman’s capsule located?

Bowman’s capsule is in the renal cortex, part of your kidney. Your kidneys are in your back, below your rib cage. Usually, you have one kidney on either side of your spine. Your kidneys are between your intestines and diaphragm. Each kidney connects to your bladder by a tube called a ureter.

What does it look like?

Bowman’s capsule looks like a pouch, sac or cup. You can only see it under a microscope. Bowman’s capsule contains fluid like blood plasma, but with no red or white blood cells or platelets.

What are the parts of Bowman’s capsule?

The glomerular capsule has two layers. A type of body tissue, simple squamous epithelium, makes up the outer (parietal) layer. These parietal cells give structure to Bowman’s capsule. Cells called podocytes form the inner (visceral) layer.

Additional Information:

Introduction

Bowman’s capsule is a part of the nephron that forms a cup-like sack surrounding the glomerulus. Bowman’s capsule encloses a space called “Bowman’s space,” which represents the beginning of the urinary space and is contiguous with the proximal convoluted tubule of the nephron. Bowman’s capsule, Bowman’s space, and the glomerular capillary network and its supporting architecture can collectively be thought of as composing the glomerulus. There are an estimated 900000 glomeruli within the cortex of a mature human kidney.

Structure and Function

In the kidney, the glomerulus represents the initial location of the renal filtration of blood. Blood enters the glomerulus through the afferent arteriole at the vascular pole, undergoes filtration in the glomerular capillaries, and exits the glomerulus through the efferent arteriole at the vascular pole.

Bowman’s capsule surrounds the glomerular capillary loops and participates in the filtration of blood from the glomerular capillaries. Bowman’s capsule also has a structural function and creates a urinary space through which filtrate can enter the nephron and pass to the proximal convoluted tubule. Liquid and solutes of the blood must pass through multiple layers to move from the glomerular capillaries into Bowman’s space to ultimately become filtrate within the nephron’s lumen.

The first step of filtration occurs through the endothelial layer of the capillaries, which is composed of fenestrated endothelial cells. These fenestrations, or slits between endothelial cells, are approximately 60 to 80 nm wide and restrict the movement of matter above this size. In addition to filtering based on size, the fenestrated endothelium carries negative charges that preferentially restrict the movement of negatively charged substances into Bowman’s space.

Filtrate next moves through the glomerular basement membrane (GBM). From the direction of the capillaries and moving towards Bowman’s capsule, three layers compose the GBM – the lamina rara interna, the lamina densa, and the lamina rara externa. Mesangial cells within the glomerulus play a role in creating and maintaining the GBM, as well as holding capillary loops together.

Following the GBM, filtrate must pass through the epithelial layer of Bowman’s capsule, which is composed of podocytes. The podocytes feature finger-like projections of cytoplasm referred to as “foot processes” or “pedicels.” These foot processes interdigitate with one another and create a further barrier through which filtrate must pass. Structures called “slit diaphragms” bridge nearby foot processes and provide structural support. The podocytes are the primary cells of the epithelium adjacent to the capillaries (the visceral epithelium) and play a role in filtration. The parietal epithelium of Bowman’s capsule is the outer layer and is composed of simple squamous epithelial cells called “parietal cells.” The parietal layer is not directly involved with filtration from the capillaries. Parietal cells play a structural role in maintaining Bowman’s capsule and are also speculated to have the ability to differentiate into podocytes to replace damaged or old podocytes. Bowman’s space is the area between the visceral and parietal epithelium of Bowman’s capsule.

In summary, filtrate entering Bowman’s space traverses through glomerular capillaries, the GBM, and the interdigitated foot processes of the podocytes and is filtered based on size and electric charge. The filtrate entering Bowman’s space has a very similar composition to that of the blood in the glomerular capillaries except for the protein, and cell content as these are the components largely prevented from entering Bowman’s space when glomerular filtration is functioning properly.

Jai Ganesh · Dark Discussions at Cafe Infinity

Combination Quotes - IV

1. That was my first lesson from Ben-Gurion. Then I saw him making peace, and I saw him making war. He mobilized me before the war. The man was a very rare combination between a real intellectual and a born leader. There is a contradiction between the two. - Shimon Peres

2. If poly A is added to poly U, to form a double or triple helix, the combination is inactive. - Francis Crick

3. Quality training is what I do now; before it was a combination of both quality and quantity. Now I'm not trying to be a world-class athlete, I don't need to train at that level. It's about being fit, fit for life. - Jackie Joyner-Kersee

4. I have always worked out, and I've gone through different phases of yoga, but the combination of Pilates three days a week with yoga is incredible. - Claudia Schiffer

5. Interestingly, many Indian companies where there's a father-and-son combination are being run as joint CEO organizations because the father has not given up running the company and the son is actively involved in running the company, and there is division of responsibilities. - Azim Premji

6. To have strongly integrated managers who have a deep understanding of technology is a rare and difficult combination to build. You have to invest a lot in selecting and training these people. - Azim Premji

7. If there is anybody who can give you a combination of quality and reasonable budget, innovative content and casting, it is me! - Pooja Bhatt

8. Books are mute as far as sound is concerned. It follows that reading aloud is a combination of two distinct operations, of two 'languages.' It is something far more complex than speaking and reading taken separately by themselves. - Maria Montessori.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#10731. What does the term in Biology Flagellum mean?

#10732. What does the term in Biology Flavin adenine dinucleotide (FAD) mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#5927. What does the noun knob mean?

#5928. What does the adjective knotty mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#2560. What does the medical term Fossa (anatomy) mean?

Jai Ganesh · Jokes

Q: What do you call Java that won't stop brewing?
A: Stand your ground coffee.
* * *
Q: Why Coffee is better than a Woman?
A: Coffee goes down easier!
* * *
Q: Where does birds go for coffee?
A: on a NESTcafe.
* * *
'Ever notice that when you serve someone a cold cup of coffee, it makes them boiling mad?
* * *
Coffee in one hand and confidence in the other.
* * *

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#9845.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#6339.

Jai Ganesh · Exercises

Hi,

2696.

Jai Ganesh · This is Cool

Hovercraft

Gist

Hovercraft are used for rescue, commercial, military and paramilitary applications to transport, save and protect lives across the world's most challenging environments.

Hovercraft are actually more like planes than boats or cars, although they are more at home moving across water than flying down the runway at Birmingham! Hovercrafts use the same 'lift' physics that an aeroplane uses to fly, although you'll never really get that far off the ground to find out.

The highest recorded speed by a hovercraft is 137.4 km/h (85.38 mph), by Bob Windt (USA) at the 1995 World Hovercraft Championships on the Rio Douro River, Peso de Regua, Portugal.

Summary

A hovercraft (pl.: also hovercraft), also known as an air-cushion vehicle or ACV, is an amphibious craft capable of travelling over land, water, mud, ice, and various other surfaces.

Hovercraft use blowers to produce a large volume of air below the hull, or air cushion, that is slightly above atmospheric pressure. The pressure difference between the higher-pressure air below the hull and lower pressure ambient air above it produces lift, which causes the hull to float above the running surface. For stability reasons, the air is typically blown through slots or holes around the outside of a disk- or oval-shaped platform, giving most hovercraft a characteristic rounded-rectangle shape.

The first practical design for hovercraft was derived from a British invention in the 1950s. They are now used throughout the world as specialised transports in disaster relief, coastguard, military and survey applications, as well as for sport or passenger service. Very large versions have been used to transport hundreds of people and vehicles across the English Channel, whilst others have military applications used to transport tanks, soldiers and large equipment in hostile environments and terrain. Decline in public demand meant that as of 2025, only two year-round public hovercraft service in the world are still in operation: Hovertravel, which serves between the Isle of Wight and Southsea in the UK, and Oita Hovercraft resumed services in Oita, Japan in July 2025.

Although now a generic term for the type of craft, the name Hovercraft itself was a trademark owned by Saunders-Roe (later British Hovercraft Corporation (BHC), then Westland), hence other manufacturers' use of alternative names to describe the vehicles.

Details

One part boat, one part airplane, and one part helicopter a hovercraft is a vehicle that traps a cushion of air underneath itself and then floats along on top of it. The air cushion holds it high above waves and land obstructions, making the craft superbly amphibious (equally capable of traveling on land or water or gliding smoothly from one to the other). That's why military hovercraft, designed for swift beach landings, are often called LCACs (Landing Craft Air Cushion).

Hovercraft come in all shapes and sizes, from one-person fun machines and small beach rescue craft to giant passenger ferries capable of carrying over 400 passengers and 50 cars. Where boats are slowed by hulls that drag deep in the water, hovercraft ride fully clear, which means they use less fuel and can reach blistering speeds of up to 145kph (90mph). From ice and water to mud and sand, from floodplains and river deltas to mangrove swamps and frozen glaciers, the great advantage of a hovercraft is that it can glide with ease to places ordinary boats struggle to reach, and land people safely even where there are no harbors or landing stages.

In practice, hovercraft have four broad applications: large commercial hovercraft are mostly used as high-speed people and car ferries; slightly smaller military LCACs are used as tried-and-tested beach landing craft; smaller niche craft are used for things like oil and gas prospecting, inshore search and rescue, and scientific surveys; and small, one-person recreational craft are often raced round courses like flying go-karts!

How does a hovercraft work?

At first sight, you might think a hovercraft works in much the same way as a helicopter: it throws air down underneath itself and then simply rides along on top. But where a helicopter balances its own weight (the force of gravity pulling it down) with a massive down-draft of air (pushing it back up again), a hovercraft works in a much more subtle way that allows it to use far less air, far more efficiently, so getting by with a much smaller engine and considerably less fuel.

The basic mechanism of a hovercraft is very simple: there's an engine (diesel or gasoline) that powers both a large central fan, pointing downward, and one or more other fans pointing backward. The central fan creates the lift that holds the craft above the waves; the other fans propel the craft backward, forward, or to the side. A rubber skirt (with or without fingers) traps a cushion of air under the craft. Side-wall hovercraft have only partial skirts: with solid sides and a skirt only at the front and back, they can be powered by quieter propellers or water-jet engines, making them quieter.

Other important parts

What else do you need to make a hovercraft? A downward-pointing fan can only blow air underneath, so hovercraft typically have one or more propeller fans on top of the hull, pointing backward to propel them forward. Usually, there's a rudder positioned just behind each fan to swivel the air it produces and steer the hovercraft in the appropriate direction. An alternative method of steering is to divert some of the down-draft from the fan through air nozzles that point horizontally—and the very first hovercraft prototype, SR.N1, effectively worked this way. Although hovercraft usually have separate fans (to create the cushion) and propellers (to drive them along), the same engines typically drive both, using gearboxes and transmissions to turn the engine's power through ninety degrees. Bigger hovercraft like the US military LCACs typically use several very hefty engines, such as powerful gas turbines. Then there's the hull itself. Most large hovercraft are built from light, rustproof, and highly durable aluminum, though hobby craft are often molded from tough composite materials such as fiber glass. Finally, you need a math to keep your pilot safe and sound—and some cargo space (either enclosed, for passengers and cars, or a large "open well" deck for carrying military cargo).

Advantages and disadvantages

Hovercraft can launch and land anywhere, travel over almost any kind of surface, race along at high speeds, and efficiently carry large numbers of passengers and equipment or hefty military cargos. They compare favorably with all kinds of rival vehicles. Since they produce an air cushion more efficiently than a helicopter, they're cheaper to operate, simpler, and easier to maintain (safer too). Where boats waste energy dragging through water and waves, a hovercraft riding smoothly on top creates little in the way of either drag or wake, so it's generally more efficient (and less disruptive to the marine environment than a propeller-driven ship).

But if hovercraft are so wonderful, why aren't they used everywhere? They're expensive initially and, though cheaper than helicopters, considerably more costly to maintain than ships and boats of similar cargo capacity (because they're essentially aircraft, not boats, and mechanically more complex). Although hovercraft successfully carried tens of millions of people between Britain and France for just over 30 years, they eventually stopped operating following the opening of the Channel Tunnel and the arrival of low-cost ferry ships and fast, wave-piercing catamarans. Hovercraft are also fairly tricky to pilot: more like helicopters, in this respect, than simple-to-operate boats. They're very noisy too, which can be a problem both for passengers and people living near the ports where they operate, and is certainly a drawback for "covert" military operations.

Additional Information:

Objective

Investigate how different amounts of air in the hovercraft's balloon affect how long the hovercraft can hover.

Introduction

A hovercraft is a vehicle that glides over a smooth surface by hovering upon an air cushion. Because of this, a hovercraft is also called an Air-Cushion Vehicle, or ACV. How is the air cushion made? The hovercraft creates vents or currents of slow-moving, low-pressure air that are pushed downward against the surface below the hovercraft. Modern ACVs often have propellers on top that create the air currents. These currents are pushed beneath the vehicle with the use of fans. Surrounding the base of the ACV is a flexible skirt, also called the curtain, which traps the air currents, keeping them underneath the hovercraft. These trapped air currents can create an air cushion on any smooth surface, land or water! Since a hovercraft can travel upon the surface of water, it is also called an amphibious vehicle.

How does the air cushion beneath the hovercraft allow the vehicle to glide to freely? The key to the ease of movement is reducing friction. A simple way to think of friction is to think about how things rub together. It is easier to rollerblade on a smooth sidewalk than a gravel path because the sidewalk has less friction. The wheels of the rollerblade do not rub as much against the sidewalk as they do all the pieces of gravel on the path. Similarly, the air cushion beneath the hovercraft greatly reduces the friction of the vehicle, allowing it to glide freely upon the land or water below.

In this aerodynamics and hydrodynamics science project, you will build your own mini hovercraft using a CD or DVD, pop-top lid from a plastic drinking bottle, and a balloon. The balloon will create the air currents the hovercraft needs to work. These air currents will travel through the pop-top lid and go beneath the hovercraft. You will fill the balloon up with different amounts of air to test if more air will cause the hovercraft to travel for longer periods of time. A balloon blown up with a lot of air will provide a large volume of air, and a balloon blown up with less air will provide a smaller volume of air.

Hovercrafts.jpg.webp

Jai Ganesh · This is Cool

2486) Automative Industry

Gist

An automobile engine is defined as a mechanical system that generates power through the combustion of fuel, producing heat energy that must be effectively dissipated to prevent overheating, typically using coolants and radiators for heat transfer.

"Automative" refers to processes, systems, or mechanisms that are automated or self-acting, often relating to machinery that operates without direct human intervention. It is distinct from "automotive" (related to motor vehicles), though they share similar roots in mechanics. The term is sometimes used to describe robotic or AI-driven automation.

Summary

Automotive industry is all those companies and activities involved in the manufacture of motor vehicles, including most components, such as engines and bodies, but excluding tires, batteries, and fuel. The industry’s principal products are passenger automobiles and light trucks, including pickups, vans, and sport utility vehicles. Commercial vehicles (i.e., delivery trucks and large transport trucks, often called semis), though important to the industry, are secondary. The design of modern automotive vehicles is discussed in the articles automobile, truck, bus, and motorcycle; automotive engines are described in gasoline engine and diesel engine.

The modern industry

The modern automotive industry is huge. In the United States it is the largest single manufacturing enterprise in terms of total value of products, value added by manufacture, and number of wage earners employed. One of every six American businesses is dependent on the manufacture, distribution, servicing, or use of motor vehicles; sales and receipts of automotive firms represent more than one-fifth of the country’s wholesale business and more than one-fourth of its retail trade. For other countries these proportions are somewhat smaller, but Japan, South Korea, and the countries of western Europe have been rapidly approaching the level in the United States.

Consolidation

The trend toward consolidation in the industry has already been traced. In each of the major producing countries the output of motor vehicles is in the hands of a few very large firms, and small independent producers have virtually disappeared. The fundamental cause of this trend is mass production, which requires a heavy investment in equipment and tooling and is therefore feasible only for a large organization. Once the technique is instituted, the resulting economies of scale give the large firm a commanding advantage, provided of course that the market can absorb the number of vehicles that must be built to justify the investment. Although the precise numbers required are difficult to determine, the best calculations, considering both the assembly operation and the stamping of body panels, place the optimum output at between 200,000 and 400,000 cars per year for a single plant. Increasingly stringent and costly regulations aimed at correcting environmental damage due to the rising number of vehicles on the road also have been a factor in the move toward consolidation.

The structural organization of these giant enterprises, despite individual variation, resembles the pattern first adopted by General Motors in the 1920s. There is a central organization with an executive committee responsible for overall policy and planning. The operating divisions are semiautonomous, each reporting directly to the central authority but responsible for its own internal management. In some situations the operating divisions even compete with each other. The Ford Motor Company was consciously reorganized on the GM pattern after World War II; other American automotive firms have similar structures.

In addition, the largest producers decentralize their manufacturing operations by means of regional assembly plants. These permit the central factory to ship frames and components rather than complete automobiles to the areas served by the assembly plants, effecting substantial savings in transportation costs. This system was developed for the Ford company in 1911.

Some alteration of that principle took place in the 1980s and ’90s as Japanese firms built new plants around the world and American and European manufacturers adopted, to varying degrees, the Japanese “just-in-time” inventory method. Rather than stockpiling a large number of parts at the assembly plant or shipping all the parts from central locations, automakers have yielded the manufacture of many noncritical components (such as seats and wheel assemblies) to independent suppliers to make the pieces at small facilities close to the assembly plants. The components are often assembled into larger groups of parts or modules (a complete instrument panel, for example) and sent to the assembly plant in the exact sequence and at the exact time needed.

Diversity of products

The automotive industry’s immense resources in production facilities and technical and managerial skills have been devoted predominantly to the building of motor vehicles, but there has been a consistent and strong incentive to extend into related products and occasionally into operations whose relationship to automobiles is remote. The Ford Motor Company, for example, once manufactured tractors and made the famous Ford Trimotor all-metal transport airplane in the late 1920s and early ’30s. GM manufactured refrigerators and diesel-powered railway locomotives. By the end of the 20th century, however, Ford and GM had divested themselves of most of their nonautomotive operations and had spun off the majority of their automotive component-making divisions into separate stock companies—Delphi Automotive Systems in the case of General Motors and Visteon Automotive in the case of Ford.

In Europe, but to a lesser extent, automakers also divested noncore operations, while depressed economic conditions in Japan forced auto companies there to begin divorcing themselves from nonautomotive and components companies in which they had long held interests. By the late 1990s the trend was toward more international consolidation of core automotive operations.

New car development

The process of putting a new car on the market has become largely standardized. If a completely new model is contemplated, the first step is a market survey. Since there may be an interval of five years between this survey and the appearance of the new car in the dealers’ showrooms, there is a distinct element of risk, as illustrated by the Ford Motor Company’s Edsel of the late 1950s. (Market research had indicated a demand for a car in a relatively high price range, but, by the time the Edsel appeared, both public taste and economic conditions had changed.) Conferences then follow for engineers, stylists, and executives to agree on the basic design. The next stage is a mock-up of the car, on which revisions and refinements can be worked out.

Because of the increasingly competitive and international nature of the industry, manufacturers have employed various means to shorten the time from conception to production to less than three years in many cases. This has been done at GM, for example, by incorporating vehicle engineers, designers, manufacturing engineers, and marketing managers into a single team responsible for the design, engineering, and marketing launch of the new model. Automakers also involve component manufacturers in the design process to eliminate costly time-consuming reengineering later. Often the component maker is given full responsibility for the design and engineering of a part as well as for its manufacture.

Manufacturing processes

The bulk of the world’s new cars come from the moving assembly line introduced by Ford, but the process is much more refined and elaborated today. The first requisite of this process is an accurately controlled flow of materials into the assembly plants. No company can afford either the money or the space to stockpile the parts and components needed for any extended period of production. Interruption or confusion in the flow of materials quickly stops production. Ford envisioned an organization in which no item was ever at rest from the time the raw material was extracted until the vehicle was completed—a dream that has not yet been realized.

The need for careful control over the flow of materials is an incentive for automobile firms to manufacture their own components, sometimes directly but more often through subsidiaries. Yet complete integration does not exist, nor is it desirable. Tires, batteries, and dashboard instruments are generally procured from outside sources. In addition, and for the same reasons, the largest companies support outside suppliers even for items of in-house manufacture. First, it may be more economical to buy externally than to provide additional internal facilities for the purpose. Second, the supplier firm may have special equipment and capability. Third, the outside supplier provides a check on the costs of the in-house operation. American companies rely more than others on independent suppliers.

Production of a new model also calls for elaborate tooling, and the larger the output, the more highly specialized the tools in which the manufacturer is willing to invest. For example, it is expensive to install a stamping press exclusively to make a single body panel for a single model, but, if the model run reaches several hundred thousand, the cost is amply justified.

The assembly process itself has a quite uniform pattern throughout the world. As a rule, there are two main assembly lines, body and chassis. On the first the body panels are welded together, the doors and windows are installed, and the body is painted and trimmed (with upholstery, interior hardware, and wiring). On the second line the frame has the springs, wheels, steering gear, and power train (engine, transmission, drive shaft, and differential) installed, plus the brakes and exhaust system. The two lines merge at the point at which the car is finished except for minor items and necessary testing and inspection. A variation on this process is “unitized” construction, whereby the body and frame are assembled as a unit. In this system the undercarriage still goes down the chassis line for the power train, front suspension, and rear axle, to be supported on pedestals until they are joined to the unitized body structure. Most passenger vehicles today are manufactured by the unitized method, and most trucks and commercial vehicles still employ a separate frame.

Assembly lines have been elaborately refined by automatic control systems, transfer machines, computer-guided welding robots, and other automated equipment, which have replaced many manual operations when volume is high. Austin Motors in Britain pioneered with its automatic transfer machines in 1950. The first large-scale automated installation in the United States was a Ford Motor Company engine plant that went into production in 1951. A universal form of automatic control has used computers to schedule assembly operations so that a variety of styles can be programmed along the same assembly line. Customers can be offered wide choices in body styles, wheel patterns, and colour combinations.

Sales and service organization

Mass production implies mass consumption, which in turn requires an elaborate distributive organization to sell the cars and to develop confidence among customers that adequate service will be available. In the early days of the industry, cars were sold directly from the factory or through independent dealers, who might handle several different makes. Many bicycle manufacturers simply used their existing sales outlets when they added horseless carriages to their line. When sales in large quantities became the objective, however, more elaborate and better organized techniques of distribution became essential.

In the United States the restricted franchise dealership became the uniform and almost exclusive method of selling new cars. In this system, dealers may sell only the particular make of new car specified in their franchise, must accept a quota of cars specified by the manufacturer, and must pay cash on delivery. In return the dealers receive some guarantee of sales territory and may be assisted in various ways by the manufacturer—financing or aid in advertising, for example. Contracts also specify that dealers must maintain service facilities according to standards approved by the manufacturer.

Seemingly weighted in favour of the manufacturer, the system has been subjected to periodic dealer complaints, producing state legislation and a federal statute in 1956 to protect dealers from arbitrary actions by manufacturers. Yet dealers have never been united in these attitudes, and no effective substitute for the restricted franchise has yet been found. On the contrary, it is becoming the general practice in other parts of the world where large-scale markets for motor vehicles have developed.

Attempts by automakers in the 1990s to move away from the traditional franchised dealer network to direct selling via the Internet met strong resistance in the United States. American dealers enlisted the help of state governments in enacting prohibitions of this practice (and in blocking attempts by automakers to own dealers through subsidiary corporations). In markets outside the United States, principally in Europe and South America, manufacturers sell directly to consumers via the Internet in limited quantities.

The market in used cars is an important part of the distribution system for motor vehicles in all countries with a substantial motor vehicle industry because it affects the sale and styling of new cars. The institution of the annual model was adopted in the United States during the 1920s to promote new-car sales in the face of used-car competition. The new model must have enough changes in styling or engineering to persuade prospective buyers that it is indeed an improvement. At the same time, it must not be so radically different from its predecessors as to give the buyer doubts about its resale potential.

Like all machinery, motor vehicles wear out. Some become scrap metal to feed steel furnaces; some go to wrecking yards where usable parts are salvaged. Throughout the world, however, the disposal of discarded motor vehicles has become a problem without a completely satisfactory solution. In many areas, landscapes are disfigured by abandoned wrecks or unsightly automobile graveyards. Spurred by European legislation requiring automakers to take back all of their end-of-life-cycle vehicles beginning in 2007, manufacturers worldwide have begun engineering new products with the complete recycling of components in mind. At the same time, they have used more and different recycled material in new vehicles. For example, old bumper covers have been recycled into fender liners or battery trays for new cars.

Details

There are a wide variety of propulsion systems available or potentially available for automobiles and other vehicles. Options included internal combustion engines fueled by petrol, diesel, propane, or natural gas; hybrid vehicles, plug-in hybrids, fuel cell vehicles fueled by hydrogen and all electric cars. Fueled vehicles seem to have the advantage due to the limited range and high cost of batteries. Some options required construction of a network of fueling or charging stations. With no compelling advantage for any particular option, car makers pursued parallel development tracks using a variety of options. Reducing the weight of vehicles was one strategy being employed.

Recent developments

The use of high-technology (such as electronic engine control units) in advanced designs resulting from substantial investments in development research by European countries and Japan seemed to give an advantage to them over Chinese automakers and parts suppliers who, as of 2013, had low development budgets and lacked capacity to produce parts for high-tech engine and power train designs.

Characteristics

The chief characteristic of an automotive engine (compared to a stationary engine or a marine engine) is a high power-to-weight ratio. This is achieved by using a high rotational speed. However, automotive engines are sometimes modified for marine use, forming a marine automobile engine.

History

In the early years, steam engines and electric motors were tried, but with limited success. In the 20th century, the internal combustion engine (ICE), became dominant. In 2015, the internal combustion engine remains the most widely used but a resurgence of electricity seems likely because of increasing concern about ICE engine exhaust gas emissions.

As of 2017, the majority of the cars in the United States are gasoline powered. In the early 1900s, the internal combustion engines faced competition from steam engines and electric motors. The internal combustion engines of the time were powered by gasoline. Internal combustion engines function with the concept of a piston being pushed by the pressure of a certain explosion. This explosion is burning the hydrocarbon within the cylinder of an engine. Out of all the cars manufactured during the time, only around one fourth are actually considered internal combustion. Within the next couple of years, the internal combustion engine came out to become the most popular automotive engine. Sometime within the 19th century, Rudolf Diesel invented a new form of internal combustion power, using a concept of injecting liquid fuel into air heated solely by compression. This is the predecessor to the modern diesel engine used in automobiles, but more specifically, heavy duty vehicles such as semi-trucks.

Engine types:

Internal combustion engines

Petrol engines quickly became the choice of manufacturers and consumers alike. Despite the rough start, noisy and dirty engine, and the difficult gear shifting, new technologies such as the production line and the advancement of the engine allowed the standard production of the gas automobiles. This is the start, from the invention of the gas automobile in 1876, to the beginning of mass production in the 1890s. Henry Ford's Model T drove down the price of cars to a more affordable price. At the same time, Charles Kettering invented an electric starter, allowing the engine to be started without the need for a mechanical hand crank. The abundance of fuel propelled gas automobiles to be highly capable and affordable. The demand of gasoline rose from 3 billion barrels in 1919 to around 15 billion in 1929.

An internal combustion engine is powered by the expansion of gas which is created by the combustion of hydrocarbon gases fuels. To elaborate, an internal combustion used the heat of a combustion created by the injected hydrocarbon fuel to create mechanical motion. At the time of the early 1900s, wood alcohol was a popular fuel for French and German automobiles, but as governments imposed large taxes on the production, the price of wood alcohol rose above that of gasoline. Gasoline engines became popular as a result of this, as internal combustion engines were commonly known as gasoline engines. Although gasoline engines became popular, they were not particularly desirable due to the dangers of fuel leaks that may cause explosions. Therefore, many inventors attempted to create a kerosene burning engine as a result. This was not a successful venture applying it for automotive usage. There are many different types of fuels for internal combustion engines. These include diesel, gasoline, and ethanol.

Steam engines

The steam engine was invented in the late 1700s, and the primary method of powering engines and soon, locomotives. One of the most popular steam automobiles was the “Stanley Steamer,” offering low pollution, power, and speed. The downside of these steam automobiles is the unreliability, complexity, and the frequent accidents that occurred with them. The startup time for a steam car may take up to 45 minutes, defeating the purpose of faster transportation. By the time the steam automobile was improved, the complexity of manufacturing relative to the gas automobiles made steam automobiles unprofitable.

A steam engine is a device which transforms heat into mechanical motion. This is provided with the usage of boilers, which create steam by boiling water. In the early 1900s, Abner Doble introduced a steam-powered car in the United States which had capabilities that could potentially overpower Ford's Model T in efficiency. Steam has been known to have very efficient fuel economy with a high power source. That is why half the world was powered by steam for almost the entirety of the 19th century and almost half the 20th century. The main drawback of the steam engine in automobiles was that operators were required to have full knowledge of boilers and steam engines before operating, as it was detrimental to the engine itself if the operator neglected it.

Electric motors

Electric vehicles seemed to be the most viable option, similar to the steam automobiles. They were first invented in the early 1800s, and became a viable option of transportation around 1890, when William Morrison created the first electric car that traveled 14 miles per hour. The electric cars offered low pollution and a soundless ride, unlike their gasoline counterparts. The greatest downside of electric cars was the range. The typical electric car could reach around 20 miles before requiring a recharge. Manufacturers could not increase the number of batteries, due to the bulkiness of the batteries at the time. Without an incentive to purchase the electric automobiles, gas automobiles were the most viable option at the time.

Electric cars use batteries to store electricity which is used to power electric motors. The battery delivers the power to the motor, which is either Alternating Current (AC) or Direct Current (DC). The difference between AC and DC motors is the sort of system that is required to run it in an electric vehicle. An AC motor is generally cheaper but the components required to run it in an electric vehicle such as the controller and inverter makes it more expensive than the DC motor. A unique feature of electric vehicles compared to its gasoline counterparts, the electric vehicle is more simple than the gasoline vehicle. The electric vehicle bypasses the gasoline car components such as the crankshaft which allows it to generate power much faster than gasoline. Because of the faster transfer of power, the electric vehicle is able to accelerate faster than gasoline cars.

In the 1970s, the electric vehicle made its reappearance because of the 1973 OPEC Oil Embargo. Previously, the abundant gasoline had become the prime source of fuel for vehicles. But after the shortage, manufacturers began looking towards electric vehicles again. Despite the improved technology from the 1800s, the electric vehicles faced similar technological flaws such as limited mileage and speed. They could only travel up to 45 miles per hour and had a range of approximately 40 miles.

Jai Ganesh · Dark Discussions at Cafe Infinity

2424) Arthur Kornberg

Gist:

Work

The substances known as DNA and RNA bear organisms' genetic code and also determine their vital processes. Arthur Kornberg took an interest in the way DNA and RNA are formed, and which enzymes steer this process. Enzymes are substances that speed up chemical processes inside organisms' cells without being consumed. By studying bacteria, Kornberg succeeded in isolating DNA polymerase in 1956–an enzyme that is active in the formation of DNA. Using a DNA molecule as a blueprint, the enzyme builds a copy of the DNA molecule from nucleotides, which are the building blocks of DNA.

Summary

Arthur Kornberg (born March 3, 1918, Brooklyn, N.Y., U.S.—died Oct. 26, 2007, Stanford, Calif.) was an American biochemist and physician who received (with Severo Ochoa) the 1959 Nobel Prize for Physiology or Medicine for discovering the means by which deoxyribonucleic acid (DNA) molecules are duplicated in the bacterial cell, as well as the means for reconstructing this duplication process in the test tube.

At the U.S. National Institutes of Health, Bethesda, Md. (1942–53), Kornberg directed research on enzymes and intermediary metabolism. He also helped discover the chemical reactions in the cell that result in the construction of flavine adenine dinucleotide (FAD) and diphosphopyridine nucleotide (DPN), coenzymes that are important hydrogen-carrying intermediaries in biological oxidations and reductions.

Appointed professor and director of the microbiology department at Washington University, St. Louis, Mo. (1953–59), he continued to study the way in which living organisms manufacture nucleotides, which consist of a nitrogen-containing organic base linked to a five-carbon sugar ring—ribose or deoxyribose—linked to a phosphate group. Nucleotides are the building blocks for the giant nucleic acids DNA and RNA (ribonucleic acid, which is essential to the construction of cell proteins according to the specifications dictated by the “message” contained in DNA).

This research led Kornberg directly to the problem of how nucleotides are strung together (polymerized) to form DNA molecules. Adding nucleotides “labeled” with radioactive isotopes to extracts prepared from cultures of the common intestinal bacterium Escherichia coli, he found (1956) evidence of an enzyme-catalyzed polymerization reaction. He isolated and purified an enzyme (now known as DNA polymerase) that—in combination with certain nucleotide building blocks—could produce precise replicas of short DNA molecules (known as primers) in a test tube.

Kornberg became a professor of biochemistry at Stanford University, Palo Alto, Calif., in 1959. From 1959 to 1969 he was department chairman. His writings include Enzymatic Synthesis of DNA (1961). Kornberg’s son Roger D. Kornberg won the 2006 Nobel Prize for Chemistry. They became the sixth father-son tandem to win Nobel Prizes.

Details

Arthur Kornberg (March 3, 1918 – October 26, 2007) was an American biochemist who won the Nobel Prize in Physiology or Medicine in 1959 for the discovery of "the mechanisms in the biological synthesis of ribonucleic acid and deoxyribonucleic acid" together with Spanish biochemist and physician Severo Ochoa of New York University. He was also awarded the Paul-Lewis Award in Enzyme Chemistry from the American Chemical Society in 1951, an L.H.D. degree from Yeshiva University in 1962, and the National Medal of Science in 1979. In 1991, Kornberg received the Golden Plate Award of the American Academy of Achievement and the Gairdner Foundation Award in 1995.

Kornberg's primary research interests were in biochemistry, especially enzyme chemistry, deoxyribonucleic acid synthesis (DNA replication) and studying the nucleic acids which control heredity in animals, plants, bacteria and viruses.

Early life and education

Born in New York City, Kornberg was the son of Jewish parents Joseph and Lena (née Katz) Kornberg, who emigrated to New York from Austrian Galicia (now part of Poland) in 1900 before they were married. His paternal grandfather had changed the family name from Queller (also spelled Kweller) to avoid the draft by taking on the identity of someone who had already completed military service. Joseph married Lena in 1904. Joseph worked as a sewing machine operator in the sweat shops of the Lower East Side, Manhattan for almost 30 years, and when his health failed, opened a small hardware store in Brooklyn, where Arthur assisted customers at the age of nine. Joseph spoke at least six languages although he had no formal education.

Arthur Kornberg was educated first at Abraham Lincoln High School and then at City College of New York. He received a B.S. in 1937, followed by a Doctor of Medicine at the University of Rochester in 1941. Kornberg had a mildly elevated level of bilirubin in his blood— jaundice due to a hereditary genetic condition known as Gilbert's syndrome—and, while at medical school, he took a survey of fellow students to discover how common the condition was. The results were published in Kornberg's first research paper in 1942.

Kornberg's internship was at Strong Memorial Hospital in Rochester, New York, in 1941–1942. After completing his medical training, he joined the armed services as a lieutenant in the United States Coast Guard, serving as a ship's doctor in 1942 in the Caribbean. Rolla Dyer, the Director of National Institutes of Health, had noticed his paper and invited him to join the research team at the Nutrition Laboratory of the NIH. From 1942 to 1945, Kornberg's work was the feeding of specialized diets to rats to discover new vitamins.

Research and career

The feeding of rats was boring work, and Kornberg became fascinated by enzymes. He transferred to Dr Severo Ochoa's laboratory at New York University in 1946, and took summer courses at Columbia University to fill out the gaps in his knowledge of organic and physical chemistry while learning the techniques of enzyme purification at work. He became Chief of the Enzyme and Metabolism Section at NIH from 1947–1953, working on understanding of ATP production from NAD and NADP. This led to his work on how DNA is built up from simpler molecules.

While working at NIH, he also researched at Washington University in St. Louis (in the lab of Carl Ferdinand Cori and Gerty Cori in 1947), and the University of California, Berkeley (in the lab of Horace Barker in 1951).

In 1953 he became professor and head of the department of microbiology, Washington University in St. Louis, until 1959. Here he continued experimenting with the enzymes which created DNA. In 1956 he isolated the first DNA polymerizing enzyme, now known as DNA polymerase I. This got him elected to the United States National Academy of Sciences in 1957 and won him the Nobel prize in 1959.

In 1960, he was elected to the American Philosophical Society, received a LL.D. again from City College and a D.Sc. at the University of Rochester in 1962. He became professor and executive head of the department of biochemistry, Stanford University, in 1959. In an interview in 1997, Arthur Kornberg (referring to Josh Lederberg) said: "Lederberg really wanted to join my department. I knew him; he's a genius, but he'd be unable to focus and to operate within a small family group like ours, and so, I was instrumental in establishing a department of genetics [at Stanford] of which he would be chairman."

Kornberg's mother died of gas gangrene from a spore infection after a routine gall bladder operation in 1939. This started his lifelong fascination with spores, and he devoted some of his research efforts to understanding them while at Washington University. From 1962 to 1970, in the midst of his work on DNA synthesis, Kornberg devoted half his research effort to determining how DNA is stored in the spore, what replication mechanisms are included, and how the spore generates a new cell. This was an unfashionable but complex area of science, and although some progress was made, eventually Kornberg abandoned this research.

The Arthur Kornberg Medical Research Building at the University of Rochester Medical Center was named in his honor in 1999.

Until his death, Kornberg maintained an active research laboratory at Stanford and regularly published scientific journal articles. For several years the focus of his research was the metabolism of inorganic polyphosphate.

The "Kornberg school" of biochemistry refers to Arthur Kornberg's many graduate students and post-doctoral fellows, i.e., his intellectual children, and the trainees of his trainees, i.e., his intellectual grandchildren. Kornberg's intellectual children include I. Robert Lehman, Charles C. Richardson, Randy Schekman, William T. Wickner, James Rothman, Arturo Falaschi and Ken-ichi Arai.

Jai Ganesh · Dark Discussions at Cafe Infinity

Combination Quotes - III

1. I want every version of a woman and a man to be possible. I want women and men to be able to be full-time parents or full-time working people or any combination of the two. - Natalie Portman

2. To us, the value of a work lies in its newness: the invention of new forms, or a novel combination of old forms, the discovery of unknown worlds or the exploration of unfamiliar areas in worlds already discovered - revelations, surprises. - Octavio Paz

3. Looking beautiful isn't just about what you apply on your face. It's the little things you do that matter. A combination of a good diet, exercise, healthy habits, discipline, dancing etc. is what my beauty routine consists of. Also, I have no bad habits; I don't drink or smoke. All these contribute to me being fit and looking good. - Madhuri Dixit

4. I have a flexible body, thanks to the combination exercise routine I follow. But I'm fairly lazy when it comes to working out my legs and back. - Shriya Saran

5. It's an interesting combination: Having a great fear of being alone, and having a desperate need for solitude and the solitary experience. That's always been a tug of war for me. - Jodie Foster

6. For me a good body is a combination of peaceful mind, positive energy and physical exercise. - Shriya Saran

7. Books are mute as far as sound is concerned. It follows that reading aloud is a combination of two distinct operations, of two 'languages.' It is something far more complex than speaking and reading taken separately by themselves. - Maria Montessori

8. Nature teaches us that tens of billions of light years may have passed, and life in all of its expressions has always been subjected to an incredible combination of matter and radiation. - Fidel Castro.

Jai Ganesh · Jokes

Q: What do you call sad coffee?
A: Despresso.
* * *
Q: Why can Starbucks get away with charging outrageous prices for coffee?
A: Because they have Italian titles for everything!
* * *
Q: What kind of coffee was served on the Titanic?
A: Sanka.
* * *
Q: Why do I not like hot drinks?
A: It's just not my cup of tea.
* * *
Q: What do Chocolate, men, and coffee have in common?
A: They are all better rich!
* * *

Jai Ganesh · Science HQ

Fetoscope/Fetoscopy

Gist

A fetoscope, also known as a fetal stethoscope or Pinard horn, is a simple, non-electronic instrument used in prenatal care to listen to a baby's heartbeat by amplifying sounds through the mother's abdomen, typically after 18-20 weeks of gestation. It's a cone-shaped device, often made of metal or plastic, that allows midwives and doctors to monitor fetal well-being without ultrasound, providing a traditional, cost-effective method for assessing the fetus.

The fetoscope allows healthcare providers, especially midwives, to monitor the heartbeat of a fetus and assess the baby's health and development. A fetal heartbeat is a vital sign that helps to detect potential issues (especially genetic conditions) early on.

Summary

A fetoscopy is a procedure that allows your healthcare team to see the inside of your uterus during pregnancy. It helps treat certain genetic conditions in a developing fetus.

Fetoscopy is a procedure during pregnancy that lets your pregnancy care provider see the fetus developing inside your uterus. Providers use it to evaluate and treat congenital disorders (diseases you’re born with). It involves inserting a thin, fiber-optic tube (endoscope or fetoscope) into your uterus through a tiny incision in your abdomen. It has a small camera on the end so your provider can see inside your uterus and amniotic sac (the sac that holds the fetus in your uterus). The fetoscope is hollow, so your provider can insert surgical tools through it, allowing them to treat certain fetal conditions or obtain samples of tissue (biopsy). In some cases, the fetoscope is inserted through your cervix instead of through your abdomen.

When is a fetoscopy done?

Fetoscopy is performed in the second or third trimester of pregnancy to treat fetal conditions or collect biopsies.

Some of the most common conditions treated with fetoscopy are:

* Twin-to-twin transfusion syndrome

Twin-to-twin transfusion syndrome is a rare, potentially life-threatening condition that occurs when identical twins aren't getting an equal share of blood while in the uterus. Your surgeon uses a fetoscope to better visualize your placenta and the blood vessels causing the condition. Then, they place a laser through the fetoscope that they use to close off the blood vessels causing uneven blood flow. This procedure is called fetoscopic laser photocoagulation.

* Amniotic band syndrome

Amniotic band syndrome occurs when the fetus gets tangled up in bands of tissue from the amniotic sac. It can restrict blood flow or cause amputation of limbs or organs. A fetoscope allows your surgeon to insert a laser device that cuts and releases the bands of tissue around the fetus.

* Congenital diaphragmatic hernia (CDH)

CDH occurs when the fetus has a hole in its diaphragm, which causes its abdominal organs to shift upward, putting pressure on the lungs. This prevents its lungs from growing properly. Surgeons use fetoscopy to insert a balloon in the fetus's airway to promote lung growth. The balloon is removed several weeks later. This procedure is called fetoscopic endoluminal tracheal occlusion (FETO).

There are other conditions fetoscopy may be used for, like treatment of placental tumors, spina bifida and other congenital diseases.

Details:

What is a Fetoscope, and Why do Midwives Use it?

A fetoscope is a medical instrument that allows healthcare providers to listen to the fetal heartbeat. Unlike a standard stethoscope, a fetoscope is designed to pick up the sounds of a baby’s heartbeat through the mother’s abdomen. It is essential to prenatal care, especially in environments prioritizing low-intervention, natural childbirth approaches, like Birthways Family Birth Center.

The Purpose of a Fetoscope

The fetoscope allows healthcare providers, especially midwives, to monitor the heartbeat of a fetus and assess the baby’s health and development. A fetal heartbeat is a vital sign that helps to detect potential issues (especially genetic conditions) early on. This monitoring is crucial throughout pregnancy, especially as the due date approaches.

Difference Between a Doppler and a Fetoscope

A fetoscope and a Doppler device detect a fetal heartbeat, but they differ in several ways:

* Technology: A Doppler uses ultrasound waves to detect the movement of the baby’s heart and translate it into sound. On the other hand, a fetoscope relies on the practitioner’s ability to manually detect and listen to the fetal heartbeat without electronic amplification.
* Sound Quality: The sound detected through a Doppler is electronically amplified to make it louder and clearer. The fetoscope provides a more natural sound but may require more skill to handle.
* Safety: The Doppler uses ultrasound waves and introduces a small amount of energy into the body. However, it is generally considered safe. A fetoscope, however, is entirely noninvasive and doesn’t involve any ultrasound or electronic waves, making it a safe option for both mother and baby.

When Can You Use it?

A fetoscope is typically used to detect a fetal heartbeat starting around 18 to 20 weeks of pregnancy. However, it requires skill and patience, as the heartbeat may not always be easy to locate, especially in early pregnancy.

Using a fetoscope is generally more effective in the later stages of pregnancy when the baby is larger and the heartbeat is stronger.

Is it Safe?

Yes, a fetoscope is entirely safe during all stages of pregnancy. It’s a non-invasive tool that does not emit radiation, ultrasound, or electronic waves. Sometimes, a fetoscope may not detect the fetal heartbeat. But this is not a concern as long as the baby is moving.

Why Do Midwives Use Them?

Midwives often prefer fetoscopes because of their safety, simplicity, and effectiveness. It aligns with the midwifery philosophy of providing natural, low-intervention care. A fetoscope creates a calm and natural environment for the mother and the baby.

To sum up, the fetoscope is a valuable tool in prenatal care. It offers a safe, effective, and natural way to monitor the baby’s health throughout pregnancy. You can learn more about fetoscopes on our YouTube channel.

Additional Information

Fetoscopy is an endoscopic procedure during pregnancy to allow surgical access to the fetus, the amniotic cavity, the umbilical cord, and the fetal side of the placenta. A small (3–4 mm) incision is made in the abdomen, and an endoscope is inserted through the abdominal wall and uterus into the amniotic cavity. Fetoscopy allows for medical interventions such as a biopsy (tissue sample) or a laser occlusion of abnormal blood vessels (such as chorioangioma) or the treatment of spina bifida.

Fetoscopy is usually performed in the second or third trimester of pregnancy. The procedure can place the fetus at increased risk of adverse outcomes, including fetal loss or preterm delivery, so the risks and benefits must be carefully weighed in order to protect the health of the mother and fetus(es). The procedure is typically performed in an operating room by an obstetrician-gynecologist.

Non-surgical fetoscopes

Fetoscopy is a surgical procedure which may involve the use of a fibreoptic device called a fetoscope. Some confusion may arise from the use of specialized forms of stethoscopes, including Pinard horns and Doppler wands, to audibly monitor fetal heart rate (FHR). These audio diagnostic tools are also called "fetoscopes" but are not related to visual fetoscopy.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#10729. What does the term in Biology Fertilisation or Fertilization mean?

#10730. What does the term in Biology Fetus or Foetus mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#5925. What does the noun plaintiff (Law) mean?

#5926. What does the noun placenta mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#2559. What does the medical term Aneurysm mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#9844.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#6338.

Jai Ganesh · Exercises

Hi,

2695.

Jai Ganesh · This is Cool

2485) Seychelles

Gist

Seychelles is considered a rich country in Africa, often ranking highest in GDP per capita on the continent due to its strong tourism and fisheries-based economy, leading to high-income status with good social programs, though some inequality exists, note WorldAtlas, Global Finance Magazine, Seychelles News Agency, ISS African Futures, U.S. Department of State (.gov), and YouTube.

Summary

Seychelles, officially the Republic of Seychelles (French: République des Seychelles; Seychellois Creole: Repiblik Sesel), is an island country and archipelagic state consisting of 115 islands in the Indian Ocean. Its capital and largest city, Victoria, is 1,500 kilometres (800 nautical miles) east of mainland Africa. Nearby island countries and territories include the Maldives, Comoros, Madagascar, Mauritius, and the French overseas departments of Mayotte and Réunion to the south; and the Chagos Archipelago to the east. Seychelles is the smallest country in Africa as well as the least populated sovereign African country, with an estimated population of 100,600 in 2022.

The Seychelles archipelago was uninhabited prior to sustained external contact. Although Arab and Swahili sailors likely knew of the islands earlier through Indian Ocean trade routes, there is no evidence of permanent settlement before European involvement.

The islands were first recorded by Europeans in the 16th century, but were not settled until the 18th century, when France formally claimed them. During the period of French colonization, enslaved Africans—many of whom had already been captured through existing African, Arab slave trade, and Indian Ocean slave trade networks—were brought to the islands for plantation labor.

It faced competing French and British interests until it came under full British control in the early 19th century. After Britain assumed control in the early 19th century, slavery was abolished and later replaced in part by indentured laborers from India. Since proclaiming independence from the United Kingdom in 1976, it has developed from a largely agricultural society to a market-based diversified economy, characterized by service, public sector, and tourism activities. From 1976 to 2015, nominal GDP grew nearly 700%, and purchasing power parity nearly 1600%. Since the late 2010s, the government has taken steps to encourage foreign investment.

As of the early 21st century, Seychelles has the highest nominal per capita GDP and the highest Human Development Index ranking of any African country. According to the 2024 V-Dem Democracy indices, Seychelles is the 43rd-ranked electoral democracy worldwide, the 1st-ranked liberal democracy in Africa, and the 2nd-ranked electoral democracy on the continent.

Seychellois culture and society is an eclectic mix of French, British, Indian and African influences, with infusions of Chinese elements. The country is a member of the United Nations, the African Union, the Southern African Development Community, and the Commonwealth of Nations.

Details:

Ethnic groups, languages, and religion

The original French colonists on the previously uninhabited islands, along with their black slaves, were joined in the 19th century by deportees from France. Asians from China, India, and Malaya (Peninsular Malaysia) arrived later in smaller numbers. Widespread intermarriage has resulted in a population of mixed descent.

Creole, also called Seselwa, is the mother tongue of most Seychellois. Under the constitution, Creole, English, and French are recognized as national languages.

More than three-fourths of the population are Roman Catholics. There are also Anglicans, Christians of other denominations, Hindus, and Muslims.

Settlement patterns and demographic trends

More than four-fifths of the population lives on Mahé, many in the capital city, Victoria. The birth and death rates, as well as the annual population growth rate, are below the global average. Some one-fifth of the population is younger than age 15, and an additional one-sixth is under age 30. Life expectancy for both men and women is significantly higher than the global average.

Economy

Seychelles has a mixed developing economy that is heavily dependent upon the service sector in general and the tourism industry in particular. Despite continued visible trade deficits, the economy has experienced steady growth. The gross domestic product (GDP) is growing more rapidly than the population. The gross national income (GNI) per capita is significantly higher than those found in most nearby continental African countries.

Agriculture, forestry, and fishing

Agriculture accounts for only a fraction of the GDP and employs an equally modest proportion of the workforce. Arable land is limited and the soil is generally poor—and the country remains dependent upon imported foodstuffs—but copra (from coconuts), cinnamon bark, vanilla, tea, limes, and essential oils are exported. Seychelles has a modern fishing industry that supplies both domestic and foreign markets; canned tuna is a particularly important product. The extraction of guano for export is also an established economic activity.

Manufacturing, finance, and trade

The country’s growing manufacturing sector—which has expanded to account for almost one-sixth of the total GDP—is composed largely of food-processing plants; production of alcoholic beverages and of soft drinks is particularly significant. Animal feed, paint, and other goods are also produced.

Seychelles’ sizable trade deficit is offset by income from the tourism industry and from aid and investment. Although the country’s relative prosperity has not made it a preferred aid recipient, it does receive assistance from the World Bank, the European Union, the African Development Bank, and a variety of contributing countries, and aid obtained per capita is relatively high. The Central Bank of Seychelles, located in Victoria, issues the official currency, the Seychelles rupee.

Seychelles’ main imports are petroleum products, machinery, and foodstuffs. Canned tuna, copra, frozen fish, and cinnamon are the most important exports, together with the reexport of petroleum products. Significant trade partners include France, the United Kingdom, the United Arab Emirates, and Italy.

Services

The service sector accounts for nearly four-fifths of the GDP and employs the largest proportion of the workforce, almost three-fourths of all laborers. After the opening of an international airport on Mahé in 1971, the tourism industry grew rapidly, and at the beginning of the 21st century it provided almost one-fourth of the total GDP. Each year Seychelles draws thousands of tourists, many attracted by the islands’ magnificent venues for scuba diving, surfing, windsurfing, fishing, swimming, and sunbathing. The warm southeasterly trade winds offer ideal conditions for sailing, and the waters around Mahé and the other islands are afloat with small boats.

Transportation and telecommunications

The majority of Seychelles’ roadways are paved, most of which are on the islands of Mahé and Praslin; there are no railroads. Ferry services operate between the islands—for example, linking Victoria with destinations that include Praslin and La Digue. Air service is centered on Seychelles International Airport, located near Victoria on Mahé, and the smaller airports and airstrips found on several islands. Seychelles has air connections with a number of foreign cities and direct flights to major centers that include London, Paris, Frankfurt, Rome, and Bangkok. Scheduled domestic flights, provided by Air Seychelles, chiefly offer service between Mahé and Praslin, although chartered flights elsewhere are also available. The tsunami that reached Seychelles in 2004 damaged portions of the transportation infrastructure, including the road linking Victoria with the international airport.

Telecommunications infrastructure in Seychelles is quite developed. The country has a high rate of cellular telephone use—among the highest in sub-Saharan Africa—and, at the beginning of the 21st century, the use of personal computers in Seychelles was several times the average for the region.

Math Is Fun Forum

#1 Re: This is Cool » Miscellany » Yesterday 21:21:47

#2 This is Cool » Neuron » Yesterday 19:43:46

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#13 This is Cool » Hovercraft » 2026-02-04 19:43:21

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#15 Re: Dark Discussions at Cafe Infinity » crème de la crème » 2026-02-04 17:04:25

#16 Dark Discussions at Cafe Infinity » Combination Quotes - III » 2026-02-04 16:48:56

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#18 Science HQ » Fetoscope/Fetoscopy » 2026-02-04 16:14:51

#19 Re: Jai Ganesh's Puzzles » General Quiz » 2026-02-04 15:38:12

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#21 Re: Jai Ganesh's Puzzles » Doc, Doc! » 2026-02-04 15:07:46

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#23 Re: Jai Ganesh's Puzzles » Oral puzzles » 2026-02-04 14:46:31

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