Posts by Jai Ganesh

Jai Ganesh · Dark Discussions at Cafe Infinity

2411) James Watson

Gist:

Work

In 1944, Oswald Avery proved that DNA is the bearer of organisms' genetic code. Further explanation was provided when James Watson and Francis Crick determined the structure of the DNA molecule in 1953. This structure–a long double helix–contains a long row of pairs of four different nitrogen bases, which allow the molecule to function like a code. The molecule's structure also explains how it is able to copy itself. The nitrogen bases always pair in the same constellations, so that if a molecule is split, its halves can be supplemented so that they form copies of the original molecule.

Summary

James Dewey Watson (April 6, 1928 – November 6, 2025) was an American molecular biologist, geneticist, and zoologist. In 1953, he and Francis Crick co-authored an academic paper in Nature proposing the double helix structure of the DNA molecule, building on research by Rosalind Franklin and Raymond Gosling. In 1962, Watson, Crick, and Maurice Wilkins were awarded the Nobel Prize in Physiology or Medicine "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material".

Watson graduated from the University of Chicago in 1947 and received his doctorate from Indiana University Bloomington in 1950. After a post-doctoral year at the University of Copenhagen with Herman Kalckar and Ole Maaløe, Watson worked at the University of Cambridge's Cavendish Laboratory in England, where he met his future collaborator Francis Crick. From 1956 to 1976, Watson was employed by the faculty of the Harvard University Biology Department, promoting research in molecular biology.

From 1968, Watson served as the director of the Cold Spring Harbor Laboratory (CSHL) in Laurel Hollow, New York, greatly expanding its level of funding and research. At CSHL, he shifted his research emphasis to the study of cancer, along with making it a world-leading research center in molecular biology. In 1994, Watson started as president and served for 10 years. He was then appointed chancellor, serving until his resignation in 2007 after making comments claiming that there is a genetic link between race and intelligence. In 2019, after the broadcast of a documentary where Watson reiterated these views on race and genetics, CSHL revoked his honorary titles and severed all ties with him.

Watson wrote many science books, including the textbook Molecular Biology of the Gene (1965) and his bestselling book The Double Helix (1968). He made derogatory comments about Rosalind Franklin, who had been responsible for gathering data that led to the discovery of the structure of DNA, and was criticized for misogyny. Between 1988 and 1992, Watson was associated with the National Institutes of Health, helping to establish the Human Genome Project, which completed the task of mapping the human genome in 2003.

Details

James Watson (born April 6, 1928, Chicago, Illinois, U.S.—died November 6, 2025, East Northport, New York) was an American geneticist and biophysicist who played a crucial role in the discovery of the molecular structure of deoxyribonucleic acid (DNA), the substance that is the basis of heredity. For this accomplishment he was awarded the 1962 Nobel Prize for Physiology or Medicine with Francis Crick and Maurice Wilkins.

Research

Watson enrolled at the University of Chicago when only 15 and graduated in 1947. From his virus research at Indiana University (Ph.D., 1950), and from the experiments of Canadian-born American bacteriologist Oswald Avery, which proved that DNA affects hereditary traits, Watson became convinced that the gene could be understood only after something was known about nucleic acid molecules. He learned that scientists working in the Cavendish Laboratory at the University of Cambridge were using photographic patterns made by X-rays that had been shot through protein crystals to study the structure of protein molecules.

After working at the University of Copenhagen, where he first determined to investigate DNA, he did research at the Cavendish Laboratory (1951–53). There Watson learned X-ray diffraction techniques and worked with Crick on the problem of DNA structure. In 1952 he determined the structure of the protein coat surrounding the tobacco mosaic virus but made no dramatic progress with DNA. Suddenly, in the spring of 1953, Watson saw that the essential DNA components—four organic bases—must be linked in definite pairs. This discovery was the key factor that enabled Watson and Crick to formulate a molecular model for DNA—a double helix, which can be likened to a spiraling staircase or a twisting ladder. The DNA double helix consists of two intertwined sugar-phosphate chains, with the flat base pairs forming the steps between them. Watson and Crick’s model also shows how the DNA molecule could duplicate itself. Thus, it became known how genes, and eventually chromosomes, duplicate themselves. Watson and Crick published their epochal discovery in two papers in the British journal Nature in April–May 1953. Their research answered one of the fundamental questions in genetics.

Later work

Watson subsequently taught at Harvard University (1955–76), where he served as professor of biology (1961–76). He conducted research on the role of nucleic acids in the synthesis of proteins. In 1965 he published Molecular Biology of the Gene, one of the most extensively used modern biology texts. He later wrote The Double Helix (1968), an informal personal account of the DNA discovery and the roles of the people involved in it, which aroused some controversy.

In 1968 Watson assumed the leadership of the Laboratory of Quantitative Biology at Cold Spring Harbor, Long Island, New York, and made it a world center for research in molecular biology. He concentrated its efforts on cancer research. In 1981 his The DNA Story (written with John Tooze) was published. From 1988 to 1992 at the National Institutes of Health, Watson helped direct the Human Genome Project, a project to map and decipher all the genes in the human chromosomes, but he eventually resigned because of alleged conflicts of interest involving his investments in private biotechnology companies.

Controversy

In early 2007 Watson’s own genome was sequenced and made publicly available on the Internet. He was the second person in history to have a personal genome sequenced in its entirety. In October of the same year, he sparked controversy by making a public statement referring to the idea that the intelligence of Africans might not be the same as that of other peoples and that intellectual differences between geographically separated peoples might arise over time as a result of genetic divergence. Watson’s remarks were immediately denounced as racist. Though he denied this charge, he resigned from his position at Cold Spring Harbor and formally announced his retirement less than two weeks later. In January 2019 the Cold Spring Harbor administration divested him of the honorary titles the laboratory had bestowed upon him. The decision came after the airing of the PBS documentary American Masters: Decoding Watson, in which Watson stated that his views on race and intelligence had not changed.

Jai Ganesh · Jai Ganesh's Puzzles

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#10701. What does the term in Geography Contour line mean?

#10702. What does the term in Geography Conurbation mean?

Jai Ganesh · Jai Ganesh's Puzzles

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#5897. What does the noun mirage mean?

#5898. What does the noun mire mean?

Jai Ganesh · Jai Ganesh's Puzzles

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#2545. What does the medical term Hypoesthesia mean?

Jai Ganesh · Dark Discussions at Cafe Infinity

College Quotes - I

1. A thorough knowledge of the Bible is worth more than a college education. - Theodore Roosevelt

2. Cauliflower is nothing but cabbage with a college education. - Mark Twain

3. You have to stay in school. You have to. You have to go to college. You have to get your degree. Because that's the one thing people can't take away from you is your education. And it is worth the investment. - Michelle Obama

4. When we make college more affordable, we make the American dream more achievable. - William J. Clinton

5. I am often amazed at how much more capability and enthusiasm for science there is among elementary school youngsters than among college students. - Carl Sagan

6. I'm going to college. I don't care if it ruins my career. I'd rather be smart than a movie star. - Natalie Portman

7. When I was in college, I wanted to be involved in things that would change the world. - Elon Musk

8. College is a refuge from hasty judgment. - Robert Frost.

Jai Ganesh · Jokes

Q: What is the name of the country near Iraq that is made entirely of cheese?
A: Curd-istan.
* * *
Q: What does a lady in a mall do with a cheesey credit card?
A: Go on a shopping brie.
* * *
Q: What cheese surrounds a medieval castle?
A: Moatzeralla.
* * *
Q: What cheese should you use to hide a horse?
A: Mascarpone.
* * *
Q: What do you call cheese that is acting crazy?
A: A basket queso.
* * *

Jai Ganesh · This is Cool

2471) Turkey

Gist

Turkey's landmass covers around 783,000 square kilometers (302,000 square miles). Out of this, about 97% lies in Asia, in the region known as Anatolia or Asia Minor. The remaining 3% lies in Europe, in a region called Eastern Thrace (also known as Turkish Thrace).

Turkey has an emerging free-market economy. It ranked as the 16th-largest in the world and 7th-largest in Europe by nominal GDP in 2025. It also ranked as the 11th-largest in the world and 5th-largest in Europe by PPP in 2025.

Summary

Turkey is a large peninsula that bridges the continents of Europe and Asia.

Turkey is a large peninsula that bridges the continents of Europe and Asia. Turkey is surrounded on three sides by the Black Sea, the Mediterranean Sea, and the Aegean Sea. Istanbul, the largest city in Turkey, is built on land in the Bosporus seaway. The city is partly in Europe and partly in Asia. Turkey is larger than the state of Texas.

Turkey is one of the most earthquake prone areas on Earth and has suffered from 13 earthquakes in the past 70 years. The North Anatolian Fault extends hundreds of miles from the Sea of Marmara in the western part of the country to the Eastern Anatolian Highlands. The fault moves back and forth about 8 inches (20 centimeters) a year.

Turkey's highest mountain, Mount Ararat has two peaks, with Great Ararat reaching 16,945 feet (5,165 meters). The mountain is considered sacred by many people and is believed to be where Noah beached his ark after the great flood.

History

Turkey is home to one of the earliest settlements in the world. Built 8,800 years ago, Catal Hoyuk was a labyrinth of 150 mud homes joined together. There were no streets in between, so people had to enter the homes through holes in the roof!

About 4,000 years ago, the Hittites created an empire in the central part of what is now called Turkey in Anatolia. They ruled for hundreds of years. The Trojan War took place when the Hittites were losing power. The ruins of the city of Troy are believed to be in the city of Hissarlik in Anatolia.

King Midas ruled western Turkey around 700 B.C. In 334 B.C., Alexander the Great took Anatolia under Macedonian Greek rule until Rome took over and Anatolia became part of Roman Asia Minor. In A.D. 330, Constantine became the Roman emperor and formed a new capital called Constantinople. After the fall of the Roman Empire it became part of the Byzantine Empire.

The city of Constantinople was conquered by the Ottomans in 1453 and Turkey became part of the Ottoman Empire. After World War I, the country was invaded by Greece, which led to the Turkish war of Independence in 1920, led by Mustafa Kemal Atatürk. In 1923, the Turkish assembly declared Turkey a republic.

The city formally became Istanbul in 1923. Turkey became a secular country, meaning there is a separation between religion and government. Women gained the right to vote in 1934.

Details

Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia, Armenia, Azerbaijan, and Iran to the east; Iraq, Syria, and the Mediterranean Sea to the south; and the Aegean Sea, Greece, and Bulgaria to the west. Turkey is home to over 85 million people; most are ethnic Turks, while Kurds are the largest ethnic minority. Officially a secular state, Turkey has a Muslim-majority population. Ankara is Turkey's capital and second-largest city. Istanbul is its largest city and economic center. Other major cities include İzmir, Bursa, and Antalya.

First inhabited by modern humans during the Late Paleolithic, present-day Turkey was home to various ancient peoples. The Hattians were assimilated by the Hittites and other Anatolian peoples. Classical Anatolia transitioned into cultural Hellenization after Alexander the Great's conquests, and later Romanization during the Roman and Byzantine eras. The Seljuk Turks began migrating into Anatolia in the 11th century, starting the Turkification process. The Seljuk Sultanate of Rum ruled Anatolia until the Mongol invasion in 1243, when it disintegrated into Turkish principalities. Beginning in 1299, the Ottomans united the principalities and expanded. Mehmed II conquered Constantinople (modern-day Istanbul) in 1453. During the reigns of Selim I and Suleiman the Magnificent, the Ottoman Empire became a global power. From 1789 onwards, the empire saw major changes, reforms, centralization, and rising nationalism while its territory declined.

In the 19th and early 20th centuries, persecution of Muslims during the Ottoman contraction and in the Russian Empire resulted in large-scale loss of life and mass migration into modern-day Turkey from the Balkans, Caucasus, and Crimea. Under the control of the Three Pashas, the Ottoman Empire entered World War I in 1914, during which the Ottoman government committed genocides against its Armenian, Greek, and Assyrian subjects. Following Ottoman defeat, the Turkish War of Independence resulted in the abolition of the sultanate and the signing of the Treaty of Lausanne. Turkey emerged as a more homogenous nation state. The Republic was proclaimed on 29 October 1923, modelled on the reforms initiated by its founder and first president, Mustafa Kemal Atatürk. Turkey remained neutral during most of World War II, but was involved in the Korean War. Several military interventions interfered with the transition to a multi-party system.

Turkey is an upper-middle-income and emerging country; its economy is the world's 16th-largest by nominal and 11th-largest by PPP-adjusted GDP. As the 15th-largest electricity producer in the world, Turkey aims to become a hub for regional energy transportation. It is a unitary presidential republic. Turkey is a founding member of the OECD, G20, and Organization of Turkic States. With a geopolitically significant location, Turkey is a NATO member and has its second-largest military force. It may be recognized as an emerging, a middle, and a regional power. As an EU candidate, Turkey is part of the EU Customs Union.

Turkey has coastal plains, a high central plateau, and various mountain ranges with rising elevation eastwards. Turkey's climate is diverse, ranging from Mediterranean and other temperate climates to semi-arid and continental types. Home to three biodiversity hotspots, Turkey is prone to frequent earthquakes and is highly vulnerable to climate change. Turkey has a universal healthcare system, growing access to education, and increasing levels of innovativeness. It is a leading TV content exporter. With numerous UNESCO World Heritage sites and intangible cultural heritage inscriptions, and a rich and diverse cuisine, Turkey is the fourth most visited country in the world.

Additional Information

Turkey, also called Türkiye, is a country that occupies a unique geographic position, lying partly in Asia and partly in Europe. Throughout its history it has acted as both a barrier and a bridge between the two continents.

Turkey is situated at the crossroads of the Balkans, Caucasus, Middle East, and eastern Mediterranean. It is among the larger countries of the region in terms of territory and population, and its land area is greater than that of any European state. Nearly all of the country is in Asia, comprising the oblong peninsula of Asia Minor—also known as Anatolia (Anadolu)—and, in the east, part of a mountainous region sometimes known as the Armenian Highland. The remainder—Turkish Thrace (Trakya)—lies in the extreme southeastern part of Europe, a tiny remnant of an empire that once extended over much of the Balkans.

Capital: Ankara
Population: (2024 est.) 86,797,000
Currency Exchange Rate: 1 USD equals 42.685 Turkish lira

The country has a north-south extent that ranges from about 300 to 400 miles (480 to 640 km), and it stretches about 1,000 miles from west to east. Turkey is bounded on the north by the Black Sea, on the northeast by Georgia and Armenia, on the east by Azerbaijan and Iran, on the southeast by Iraq and Syria, on the southwest and west by the Mediterranean Sea and the Aegean Sea, and on the northwest by Greece and Bulgaria. The capital is Ankara, and its largest city and seaport is Istanbul.

Of a total boundary length of some 4,000 miles (6,440 km), about three-fourths is maritime, including coastlines along the Black Sea, the Aegean, and the Mediterranean, as well as the narrows that link the Black and Aegean seas. These narrows—which include the Bosporus, the Sea of Marmara, and the Dardanelles—are known collectively as the Turkish straits; Turkey’s control of the straits, the only outlet from the Black Sea, has been a major factor in its relations with other states. Most of the islands along the Aegean coast are Greek; only the islands of Gökçeada and Bozcaada remain in Turkish hands. The maritime boundary with Greece has been a source of dispute between the two countries on numerous occasions since World War II.

A long succession of political entities existed in Asia Minor over the centuries. Turkmen tribes invaded Anatolia in the 11th century ce, founding the Seljuq empire; during the 14th century the Ottoman Empire began a long expansion, reaching its peak during the 17th century. The modern Turkish republic, founded in 1923 after the collapse of the Ottoman Empire, is a nationalist, secular, parliamentary democracy. After a period of one-party rule under its founder, Mustafa Kemal (Atatürk), and his successor, Turkish governments since the 1950s have been produced by multiparty elections based on universal adult suffrage.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#9829.

Jai Ganesh · Jai Ganesh's Puzzles

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#6323.

Jai Ganesh · Exercises

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2680.

Jai Ganesh · This is Cool

Atlas Mountains

Gist

The Atlas Mountains are located in North Africa along the northwestern coast. They are located in the countries of Morocco, Algeria, and Tunisia.

The Atlas Mountains are a major North African range separating the Mediterranean/Atlantic from the Sahara, stretching across Morocco, Algeria, and Tunisia, with its highest peak, Toubkal (4,167m), in Morocco; they are characterized by diverse ecosystems, Berber populations, and historical significance, acting as a climatic barrier and home to unique flora and fauna.

Summary

The Atlas Mountains are located in Northern Africa. The range forms a natural barrier between the Sahara Desert and the coast. It is also a natural boundary between the Mediterranean and Atlantic coastlines.

How Long are the Atlas Mountains?

The Atlas Mountains are one of Africa’s most extensive mountain systems, covering 1,553 miles (2,500 kilometers).

What Countries are the Atlas Mountains in?

The Atlas Mountains run through the heart of Morocco, Algeria, and Tunisia. Each country claims its unique stretch of the mountain range.

There are four distinct sections of the Atlas Mountains:

* Anti-Atlas, High Atlas, and Middle Atlas (Morocco)
* Tell Atlas (Morocco, Algeria, Tunisia)
* Aurès Mountains (Algeria, Tunisia)
* Saharan Atlas (Algeria).

Details

The Atlas Mountains are a mountain range in the Maghreb in North Africa. They separate the Sahara Desert from the Mediterranean Sea and the Atlantic Ocean; the mountain range stretches around 2,500 km (1,600 mi) through Morocco, Algeria and Tunisia. The mountains are associated with the Titan Atlas. The range's highest peak is Toubkal, in central Morocco, with an elevation of 4,167 metres (13,671 ft). The Atlas Mountains are primarily inhabited by Berber populations.

The terms for 'mountain' are Adrar and adras in some Berber languages, and these terms are believed to be cognates of the toponym Atlas. The mountains are home to a number of animals and plants which are mostly found within Africa but some of which can be found in Europe. Many of these species are endangered and a few are already extinct. The weather is generally cool but summers are sunny, and the average temperature there is 25 °C.

Geology

Atlas was formed during three subsequent phases of Earth's geology.

The first tectonic deformation phase involves only the Anti-Atlas, which was formed in the Paleozoic Era (~300 million years ago) as the result of continental collisions. North America, Europe and Africa were connected millions of years ago.

The Anti-Atlas Mountains are believed to have originally been formed as part of the Alleghenian orogeny. These mountains were formed when Africa and America collided and were once a chain rivaling today's Himalayas. Today, the remains of this chain can be seen in the Fall Line region in the Eastern United States. Some remnants can also be found in the later formed Appalachians in North America.

A second phase took place during the Mesozoic Era (before ~66 My). It consisted of a widespread extension of the Earth's crust that rifted and separated the continents mentioned above. This extension was responsible for the formation of many thick intracontinental sedimentary basins including the present Atlas. Most of the rocks forming the surface of the present High Atlas were deposited under the ocean at that time.

In the Paleogene and Neogene Periods (~66 million to ~1.8 million years ago), the mountain chains that today constitute the Atlas were uplifted, as the land masses of Europe and Africa collided at the southern end of the Iberian Peninsula. Such convergent tectonic boundaries occur where two plates slide towards each other forming a subduction zone (if one plate moves underneath the other), and/or a continental collision (when the two plates contain continental crust). In the case of the Africa-Europe collision, it is clear that tectonic convergence is partially responsible for the formation of the High Atlas, as well as for the closure of the Strait of Gibraltar and the formation of the Alps and the Pyrenees.

However, there is a lack of evidence for the nature of the subduction in the Atlas region, or for the thickening of the Earth's crust generally associated with continental collisions. One of the most striking features of the Atlas to geologists is the relatively small amount of crustal thickening and tectonic shortening despite the important altitude of the mountain range. Recent studies suggest that deep processes rooted in the Earth's mantle may have contributed to the uplift of the High and Middle Atlas.

Natural resources

The Atlas are rich in natural resources. There are deposits of iron ore, lead ore, copper, silver, mercury, rock salt, phosphate, marble, anthracite coal and natural gas among other resources.

Additional Information

Atlas Mountainsis a series of mountain ranges in northwestern Africa, running generally southwest to northeast to form the geologic backbone of the countries of the Maghrib (the western region of the Arab world)—Morocco, Algeria, and Tunisia. They extend for more than 1,200 miles (2,000 kilometres), from the Moroccan port of Agadir in the southwest, to the Tunisian capital of Tunis in the northeast. Their thick rim rises to form a high sill separating the Mediterranean basin to the north from the Sahara to the south, thus constituting a barrier that hinders, without completely preventing, communication between the two regions. Across the mountains filter both air masses and human migrations. It is, however, only in the east–west direction that the Atlas Mountains facilitate movement. These are the conditions that create at the same time both the individuality and the homogeneity of the Atlas countries. Although the Saharan region is more likely to be described as the archetypal North African habitat, it is the well-watered mountains north of this vast desert that provide the foundation for the livelihood of most of the peoples of North Africa and a striking green or white background for many North African towns.

Physical features:

Physiography

The Atlas mountain system takes the shape of an extended oblong, enclosing within its ranges a vast complex of plains and plateaus.

The northern section is formed by the Tell Atlas, which receives enough rainfall to bear fine forests. From west to east several massifs (mountainous masses) occur. The first of these is Er-Rif, which forms a half-moon-shaped arc in Morocco between Ceuta and Melilla; its crest line exceeds 5,000 feet (1,500 metres) above sea level at several points, reaching 8,058 feet at Mount Tidirhine. East of the gap formed by the Moulouya River the Algerian ranges begin, among which the rugged bastion of the Ouarsenis Massif (which reaches a height of 6,512 feet), the Great Kabylie, which reaches 7,572 feet at the peak of Lalla Khedidja, and the mountains of Kroumirie in Tunisia are all prominent.

The southern section, which is subject to desert influences, is appropriately called the Saharan Atlas. It includes in the centre a palisade formed by shorter ranges, such as the Ksour and Ouled-Naïl mountains, grouped into massifs between two mighty ranges—the Moroccan High Atlas to the west and the Aurès Mountains to the east. The High Atlas culminates in Mount Toubkal at 13,665 feet (4,165 metres), the highest point in the Atlas Mountains, which is surrounded by high snowcapped peaks; the Aurès Mountains are formed of long parallel folds, which reach a height of 7,638 feet at Mount Chelia.

The Tell Atlas and the Saharan Atlas merge in the west into the long folds of the Middle Atlas and in the east join together in the Tébessa and Medjerda mountains.

Geology

If the relief of the Atlas region is relatively simple, its geology is complex. In essence, the two Atlases comprise two different structural regions.

The Tell Atlas originally arose out of a basin filled with sediment, which was dominated to the north by a marginal rim, of which the massifs of Tizi Ouzou, Collo, and Edough are the remnants. Its elevation took place during a lengthy mountain-building process that was marked by upheavals in the Paleogene and Neogene periods (i.e., about 65 to 2.6 million years ago); over the cluster of folds that were uplifted from the rift valley were spread sheets of flysch (deposits of sandstones and clays), which were carried down from the north over the top of the marginal rim. Thus the Tell Atlas represents an example of a young folded mountain range still in the process of formation, as is shown by the earth tremors to which it is subject.

To the south the Saharan Atlas belongs to another structural grouping, that of the vast plateaus of the African continent, which form part of the ancient base rock largely covered by sediments deposited by shallow seas and by alluvial deposits. The Saharan Atlas is the result either of the mighty folding of the substructure that raised up fragments of the base rock—such as the horst (uplifted block of the Earth’s crust), which constitutes the Moroccan High Atlas—or else of the crumpling into folds of the Earth’s crust during the Jurassic Period (about 200 to 145 million years ago) and the Cretaceous Period (about 145 to 65 million years ago).

Drainage

The seasonal character of the rains, which fall in torrents, determines the characteristics of drainage in the Atlas: the runoff feeds streams that are of great erosive capacity and that have cut their way down through the thickness of accumulated layers of sediment to form deep narrow gorges difficult to cross. The pre-Roman fortress of Cirta (now called Constantine) in Algeria stands on a rock sculptured out by one such stream, the winding Rhumel River.

The great Maghribian wadis (French: oueds; channels of watercourses that are dry except during periods of rain) issue from the Atlas ranges. Among the more perennial rivers are the Moulouya, which rises from the Middle Atlas, and the Chelif, which rises from the Amour Mountains. Destructive of the soils of their headstreams, they deposit their loads of silt at the foot of the mountain ranges or else leave a long line of conical deposits locally known as dirs (“hills”).

Soils

Good soil is sparse at higher altitudes in the Atlas region. Most often nothing is to be found but bare rock, debris, and fallen materials incessantly renewed by landslides. Two materials predominate—limestone, which forms ledges that are half-buried in rough debris, and marls (chalky clays) cut by erosion into a maze of ravines and crumbling gullies. The rarer sandstones favour forest growth. The best soils are the alluvia found on the terraced slopes and on the valley bottoms.

Climate of the Atlas Mountains

The Atlas Mountains are the meeting place of two different kinds of air masses—the humid and cold polar air masses that come from the north and the hot and dry tropical air masses that move up from the south. To the influences of altitude and latitude must be added that of aspect or exposure.

Rain is more plentiful in the Tell Atlas than in the Saharan Atlas, and more so to the northeast than to the southwest: the highest rainfall is recorded east of the Tell Atlas. ʿAyn ad-Darāhim in the Kroumirie mountains receives 60 inches (1,524 millimetres) a year; nowhere in the Anti-Atlas Mountains, south of the High Atlas, is the total more than 17 inches a year. In a single massif the slopes with a northern exposure receive more rainfall than those with a southern exposure.

With increased altitude the temperature drops rapidly; despite the proximity of the sea, the coastal massifs are cold regions. At 6,575 feet the summits of Mount Babor in the Little Kabylie region are covered with snow for four or five months, while the Moroccan High Atlas retains its snows until the height of summer. Winter in the Atlas is hard, imposing severe conditions upon the inhabitants.

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Jai Ganesh · Science HQ

Patella

Gist

The patella is your kneecap. It's the bone at the front of your knee joint. It's the biggest bone in your body embedded in a tendon (a sesamoid bone).

The patella, or kneecap, is the largest sesamoid bone in the body, a flat, triangular bone at the front of the knee joint that protects it and helps with leg extension by acting as a lever for the quadriceps muscle. Embedded in the quadriceps tendon, it connects the thigh muscles to the shinbone (tibia) via the patellar ligament, allowing for smooth movement and improving the efficiency of knee extension.

A patella (kneecap) injury can range from moderately painful strains (tendinitis) to severe, debilitating fractures or dislocations, often causing significant pain, swelling, and inability to straighten the knee, with recovery potentially taking months, requiring rest, bracing, or surgery depending on the injury's severity. Serious tears or displaced fractures often need surgery, while less severe issues might heal with immobilization and physical therapy, but all require prompt medical attention.

Summary

The patella (pl.: patellae or patellas), also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as mice, cats, birds, and dogs, but not in whales, or most reptiles.

In humans, the patella is the largest sesamoid bone (i.e., embedded within a tendon or a muscle) in the body. Babies are born with a patella of soft cartilage which begins to ossify into bone at about four years of age.

Structure

The patella is a sesamoid bone roughly triangular in shape, with the apex of the patella facing downwards. The apex is the most inferior (lowest) part of the patella. It is pointed in shape, and gives attachment to the patellar ligament.

The front and back surfaces are joined by a thin margin and towards centre by a thicker margin. The tendon of the quadriceps femoris muscle attaches to the base of the patella., with the vastus intermedius muscle attaching to the base itself, and the vastus lateralis and vastus medialis are attached to outer lateral and medial borders of patella respectively.

The upper third of the front of the patella is coarse, flattened, and rough, and serves for the attachment of the tendon of the quadriceps and often has exostoses. The middle third has numerous vascular canaliculi. The lower third culminates in the apex which serves as the origin of the patellar ligament. The posterior surface is divided into two parts.

The upper three-quarters of the patella articulates with the femur and is subdivided into a medial and a lateral facet by a vertical ledge which varies in shape.

In the adult the articular surface is about 12 {cm}^{2} (2 sq in) and covered by cartilage, which can reach a maximal thickness of 6 mm (1⁄4 in) in the centre at about 30 years of age. Owing to the great stress on the patellofemoral joint during resisted knee flexion, the articular cartilage of the patella is among the thickest in the human body.

The lower part of the posterior surface has vascular canaliculi filled and is filled by fatty tissue, the infrapatellar fat pad.

Function

The primary functional role of the patella is knee extension. The patella increases the leverage that the quadriceps tendon can exert on the femur by increasing the angle at which it acts.

The patella is attached to the tendon of the quadriceps femoris muscle, which contracts to extend/straighten the knee. The patella is stabilized by the insertion of the horizontal fibres of vastus medialis and by the prominence of the lateral femoral condyle, which discourages lateral dislocation during flexion. The retinacular fibres of the patella also stabilize it during exercise.

Details

The patella is your kneecap. Even though it protects your joint, it’s not just a cover for your knee. It also helps muscles, tendons and ligaments work correctly, as well as helps you move your knee. If your bones are weakened by osteoporosis, you have an increased risk for fractures.

What is the patella?

The patella is your kneecap. It’s the bone at the front of your knee joint. It’s the biggest bone in your body embedded in a tendon (a sesamoid bone). Your patella helps your quadriceps muscle move your leg, protects your knee joint, and supports lots of important muscles, tendons and ligaments.

Traumas that hurt your knee are the most common patella injuries, including dislocations and bone fractures. If you do experience an injury, you might need surgery to repair your bone and physical therapy to help you regain your strength and ability to move.

Your patella — like all bones — can be affected by osteoporosis.

Function:

What does the patella do?

Your patella has two main jobs:

* Working with your quadriceps muscle to extend and straighten your leg.
* Protecting your knee joint.

Anatomy:

Where is the patella located?

The patella is at the front of your knee and covers the knee joint itself. It’s a bridge between your quad muscle and your lower leg.

What does the patella look like?

The patella is shaped like an oval with a slight point at the bottom. The top (base) is connected to your quad muscle by the quadriceps tendon. The patellar ligament connects the bottom (apex) of your patella to your tibia (shin bone).

The patella’s medial facet (the side closer to the inside of your body) articulates (moves) with your femur’s medial condyle. The lateral facet (the side closer to the outside of your body) moves with your femur’s lateral condyle.

These parts and labels are usually more for your healthcare provider to use, as they describe where you’re having pain or issues. If you ever break your patella — a patellar fracture — your provider might use some of these terms to describe where your bone was damaged.

How big is the patella?

Most adults’ patellae (the plural for patella) are around 1.75 inches long and 1.5 inches wide.

Conditions and Disorders:

What are the common conditions and disorders that affect the patella?

Lots of conditions cause knee pain (anterior knee pain or chondromalacia patella). Many of the most common causes of knee pain damage the patella or the area around it, including:

* Patellofemoral pain syndrome.
* Patellar dislocations.
* Patellar instability.
* Patella fractures.
* Patellar tendinitis.

Patellar dislocation vs. patellar subluxation

Some people might think they have a patellar dislocation when they actually have a patellar subluxation.

A subluxation is a partial dislocation. It means that your bone is unstable in the joint and may have strayed a little out of place, but it hasn’t popped all the way out. When you have a patella subluxation, your kneecap still fits in its groove and you can still walk. You may feel uncomfortable or unsteady, and you may hear a popping noise as your patella moves. Injuries or your joint being too loose can cause patellar subluxation.

Visit a healthcare provider if you’re experiencing new symptoms in your knees or have trouble walking or moving.

Osteoporosis

Osteoporosis can affect any bone in your body, including your patella. Osteoporosis weakens bones, making them more susceptible to sudden and unexpected fractures. Many people don’t know they have osteoporosis until after it causes them to break a bone. There usually aren’t obvious symptoms.

Women and adults older than 50 have an increased risk for developing osteoporosis. Talk to your provider about a bone density test that can catch osteoporosis before it causes a fracture.

What tests are done on the patella?

The most common test providers do on the patella is the patella reflex test.

Your provider will tap your knee just below your patella with a special hammer. The sudden stimulation on your tendons triggers an involuntary reflex — a reaction you can’t control — which should make your leg extend. This is the patellar reflex.

Your provider might perform this test as part of your routine examination or if they suspect something is affecting your body’s nervous system.

If you’ve experienced a patellar injury or fracture, your provider or surgeon might need imaging tests, including:

* X-rays.
* Magnetic resonance imaging (MRI).
* CT scan.

What are common treatments for the patella?

Usually, your patella won’t need treatment unless you’ve experienced an injury or fracture or have knee pain.

Many issues that affect your patella can be treated with similar treatments, including:

* Wearing a brace or other immobilizing device.
* Resting or avoiding the activity that caused your injury.
* Physical therapy.
* At-home treatments like icing and over-the-counter pain relievers.

Talk to your provider about which treatments you’ll need and how long you should expect them to take.

Patella fracture treatment

How your fracture is treated depends on which type it is and what caused it. You’ll need some form of immobilization — like a splint or cast — and might need surgery to realign (set) your bone to its correct position and secure it in place so it can heal. Ask your provider or surgeon how long it will take your specific fracture to recover.

Osteoporosis treatment

Treatments for osteoporosis can include:

* Exercise.
* Vitamin and mineral supplements.
* Prescription medications.

Exercise and taking supplements are usually all you’ll need to prevent osteoporosis. A healthcare provider can help develop a treatment plan that’s customized for you and your bone health.

Care:

Keeping your patella healthy

Following a diet and exercise plan that’s healthy for your and seeing a healthcare provider for regular checkups will help you maintain your bone (and overall) health. Talk to a provider about a bone density test if you’re older than 50 or have a family history of osteoporosis.

Follow these general safety tips to reduce your risk of an injury:

* Always wear your seatbelt.
* Wear the right protective equipment for all activities and sports.
* Make sure your home and workspace are free from clutter that could trip you or others.
* Always use the proper tools or equipment at home to reach things. Never stand on chairs, tables or countertops.
* Follow a diet and exercise plan that’ll help you maintain good bone health.
* Use a cane or walker if you have difficulty walking or have an increased risk of falls.

A note from Cleveland Clinic

Your patella, or kneecap, does a lot of work for a relatively small bone. It’s an important bridge between your upper and lower leg. It protects the rest of your knee joint and helps it function as it should. Anything you do to improve your overall health will also help keep your bones strong. Talk to your provider about your osteoporosis risk, and ask them about ways you can support your bones as you age.

Additional Information

The patella (kneecap) is located at the front of the knee joint, within the patellofemoral groove of the femur. Its superior aspect is attached to the quadriceps tendon and inferior aspect to the patellar ligament.

It is classified as a sesamoid type bone due to its position within the quadriceps tendon, and is the largest sesamoid bone in the body.

Bony Landmarks

The patella has a triangular shape, with anterior and posterior surfaces. The apex of the patella is situated inferiorly and is connected to the tibial tuberosity by the patellar ligament. The base forms the superior aspect of the bone and provides the attachment area for the quadriceps tendon.

The posterior surface of the patella articulates with the femur, and is marked by two facets:

* Medial facet – articulates with the medial condyle of the femur.
* Lateral facet – articulates with the lateral condyle of the femur.

Functions

The patella has two main functions:

* Leg extension – Enhances the leverage that the quadriceps tendon can exert on the femur, increasing the efficiency of the muscle.
* Protection – Protects the anterior aspect of the knee joint from physical trauma.

Jai Ganesh · This is Cool

Mosquito

Gist

Mosquitoes are attracted to the carbon dioxide (CO2) we exhale, body heat, and specific skin odors like lactic acid, ammonia, and carboxylic acids, often from skin bacteria, with factors like dark clothing, Type O blood, alcohol, and scented products also playing a role, while they find standing water for breeding. They use these cues, detected by antennae, to find hosts for blood meals (females) and breeding sites.

The mosquito is the world's deadliest animal. Spreading diseases like dengue, West Nile, Zika, chikungunya, malaria, and lymphatic filariasis, the mosquito kills more people than any other creature in the world.

Summary

Mosquitoes are one of the most intensely studied creatures on the planet. Their role in disease transmission and nuisance biting makes them worthy of such attention. There are over 3,500 species of mosquito on Earth and they are found on every continent except Antarctica. Yet, from this great diversity, only a small handful can carry the pathogens that cause disease and it is these species which have been studied most intensely. For the purposes of public health, this substantial body of research has helped us to understand mosquito-borne disease transmission and informed the development of mosquito- and disease-control methods. But parallel to this, a fascinating and complex biology has been revealed, showing the mosquito’s incredible and unusual behavioural, anatomical and physiological traits. This chapter will explore some of the unique aspects of mosquito biology and ecology, drawn from the ever-growing body of research on the most medically important species, and highlight the sophisticated adaptations of mosquitoes to their ecological niche.

Details

A mosquito, (family Culicidae), is any of approximately 3,500 species of familiar insects, some of which are important in public health because of the bloodsucking habits of the females. Mosquitoes are known to transmit serious diseases, including yellow fever, Zika fever, malaria, filariasis, chikungunya fever, and dengue, though less than 10 percent of all mosquito species are vectors of human disease. Ecologically, mosquitoes serve as an important food source for countless animals and play an integral role in local food webs. In natural bodies of standing water, mosquito eggs and larvae make up a substantial portion of the biomass in many places, providing food not only for fishes but also for turtles, amphibians, and even the larvae of other insects, such as dragonflies. In terrestrial environments, mosquitoes are a major food source for bats, birds, lizards, frogs, spiders, and predatory insects, and also serve as pollinators.

Mosquitoes are found in nearly every part of the world. They thrive in warm, humid environments and are especially abundant in tropical and subtropical regions, though some species inhabit temperate zones and survive cold seasons by overwintering in the egg or adult stage. In 2025, following record-breaking spring heat, mosquitoes (a male and two female of the species Culiseta annulata) were detected in the mountains of Iceland for the first time. If the population there survives the winter and becomes established, Antarctica would become the last remaining mosquito-free land mass on Earth. Mosquitoes are expected to benefit from anthropogenic climate change, as rising global temperatures, milder winters, and increasingly frequent heat waves, storms, and floods expand suitable habitats and create more standing water for breeding. A number of species, including several important vectors of disease, have already encroached into novel areas in higher latitudes and altitudes.

Physical features and behavior

The slender elongated body of the adult is covered with scales, as are the veins of the wings. Mosquitoes are also characterized by long fragile-looking legs and elongated piercing mouthparts. The feathery antennae of the male are generally bushier than those of the female. The males, and sometimes the females, feed on nectar and other plant juices and are known pollinators. In most species, however, the females require the proteins obtained from a blood meal in order to mature their eggs. Different species of mosquitoes show preferences and, in many cases, narrow restrictions as to host animals. The females of Uranotaenia sapphirina, for example, specialize on earthworms and leeches, while those of a related species, Uranotaenia lowii, feast only on the blood of frogs and toads. Mammals, birds, and reptiles are common hosts for many mosquitoes.

The eggs are laid on the surface of water and hatch into aquatic larvae, or wrigglers, which swim with a jerking, wriggling movement. In most species, larvae feed on algae and organic debris, although a few are predatory and may even feed on other mosquitoes. Unlike most insects, mosquitoes in the pupal stage, called tumblers, are active and free-swimming. The pupae breathe by means of tubes on the thorax. The adults mate soon after emerging from their pupal cases. The duration of the life cycle varies greatly, depending on the species.

Mosquitoes are apparently attracted to host animals by moisture, lactic acid, carbon dioxide, body heat, and movement. The mosquito’s hum results from the high frequency of its wingbeats, and the female’s wingbeat frequency may serve as a means of sex recognition.

Major genera and species

There are three important mosquito genera that cause disease in humans.

Aedes mosquitoes

The genus Aedes carries the pathogens that cause yellow fever, dengue, Zika fever, chikungunya fever, and encephalitis. Like Culex, it holds its body parallel to the resting surface, with the proboscis bent down. The wings are uniformly colored. Aedes may be distinguished from Culex by its silver thorax with white markings and posterior spiracular bristles. The tip of the female’s abdomen is pointed and has protruding cerci. Aedes usually lays eggs in floodwater, rain pools, or salt marshes. The eggs are capable of withstanding long periods of dryness. The short, stout larvae have a breathing tube containing a pair of tufts, and the larvae hang head down at a 45° angle from the water surface. The life cycle may be as short as 10 days or, in cool weather, as long as several months.

A. aegypti, the important carrier of the virus responsible for yellow fever and other diseases, has white bands on its legs and spots on its abdomen and thorax. This domestic species breeds in almost any kind of container, from flower pots to discarded car-tire casings. The Asian tiger mosquito (A. albopictus) is another serious disease vector that has spread from its native Asia to the Americas.

The eastern salt marsh mosquito (A. sollicitans), the black salt marsh mosquito (A. taeniorhynchus), and the summer salt marsh mosquito (A. dorsalis) are important mosquitoes in coastal marsh areas that experience daily or occasional flooding with brackish or salt water. They are prolific breeders, strong fliers, and irritants to animals, including humans.

Anopheles mosquitoes

Anopheles, the only known carrier of malaria, also transmits filariasis and encephalitis. Anopheles mosquitoes are easily recognized from their resting position, in which the proboscis, head, and body are held in a straight line with one another but at an angle to the surface. The spotted coloring on the wings results from colored scales. Egg laying usually occurs in water containing heavy vegetation. The female deposits her eggs singly on the water surface. Anopheles larvae lie parallel to the water surface and breathe through posterior spiracular plates on the abdomen instead of through a tube, as do most other mosquito larvae. The life cycle is from 18 days to several weeks.

Culex mosquitoes

The genus Culex is a carrier of viral encephalitis and, in tropical and subtropical climates, of filariasis. It holds its body parallel to the resting surface and its proboscis is bent downward relative to the surface. The wings, with scales on the veins and the margin, are uniform in color. The tip of the female’s abdomen is blunt and has retracted cerci (sensory appendages). Egg laying may occur on almost any body of fresh water, including standing polluted water. The eggs, which float on the water, are joined in masses of 100 or more. The long and slender Culex larvae have breathing tubes that contain hair tufts. They hang head downward at an angle of 45° from the water surface. The life cycle, usually 10 to 14 days, may be longer in cold weather.

The northern house mosquito (C. pipiens) is the most abundant species in northern regions, while the southern house mosquito (C. quinquefasciatus) is abundant in southern regions, namely the tropics and subtropics.

Mosquito control

Because mosquitoes are such prolific carriers of infectious diseases, preventing them from feeding on humans is considered to be a key global health strategy. The likelihood of disease transmission can be reduced through the use of mosquito repellent, long clothing that covers the arms and legs, screens in open doors and windows, and insecticide-treated mosquito bed nets. Mosquito populations can be controlled in part through the elimination of sources of standing water, which provide ideal breeding sites for mosquitoes. A surface film of oil can be applied to standing water to clog the breathing tubes of wrigglers, which may also be killed by larvicides. Biological control using larvivorous fish, such as the mosquitofish (Gambusia affinis) is an option for some bodies of water. At times, insecticides are used to destroy adult mosquitoes indoors.

Aerial and truck-spraying applications of insecticides are commonly used in urban areas. Such applications are often done in the early evening to reduce the impact on pollinators, and ideally, they consist of insecticides that leave minimal residual effects, though regulations vary widely across the globe. Even in developed countries, commercial yard treatments are often less regulated than municipal applications and are frequently overused by the public. Nontarget fly species and many beneficial insects, including bees, are often killed with broad or persistent insecticide treatments. Naled, pyrethrins, pyrethroids, and other common insecticides used for mosquito control can make their way into waterways and harm aquatic invertebrates, affecting food webs far beyond the application site. Using mosquito insecticides in adverse weather conditions can exacerbate their negative environmental impacts.

Researchers have investigated the possibility of manipulating mosquito populations to prevent the production of viable mosquito offspring, thereby reducing the number of mosquitoes. Researchers have also identified ways in which male mosquitoes may be genetically engineered to transmit a gene to their offspring that causes the offspring to die before becoming sexually mature. Scientists have found that female mosquitoes are less attracted to humans when exposed to small compounds related to the neurotransmitter molecule neuropeptide Y. These compounds could be emitted via dispensers in areas where mosquitoes are abundant, helping to deter them from biting humans.

Additional Information

Many mosquitoes, such as Culex quinquefasciatus, lay their eggs on the surface of fresh or stagnant water. The water may be in tin cans, barrels, horse troughs, ornamental ponds, swimming pools, puddles, creeks, ditches, catch basins or marshy areas. Mosquitoes prefer water sheltered from the wind by grass and weeds.

Culex mosquitoes usually lay their eggs at night over a period of time sticking them together to form a raft of from 100 to 300 eggs. A raft of eggs looks like a speck of soot floating on the water and is about 1/4 inch long and 1/8 inch wide. A female mosquito may lay a raft of eggs every third night during its life span.

Anopheles and many other mosquitoes lay their eggs singly on the water surface. Aedes and Ochlerotatus mosquitoes lay their eggs singly, usually on damp soil. Aedes and Ochlerotatus eggs are more resistant to drying out (some require complete drying out before the eggs will hatch) and hatch only when flooded with water (salt water high tides, irrigated pastures, treeholes flooded by rains, flooded stream bottoms). Anopheles, Culex and Mansonia eggs are susceptible to drying out during extended droughts.

Tiny mosquito larvae (1st instar) emerge from the eggs within 24 - 48 hours almost in unison.

Mosquito Larva

Mosquito larvae, commonly called "wigglers," live in water from 4 to 14 days depending on water temperature.

Larvae of almost all species must come to the surface at frequent intervals to obtain oxygen through a breathing tube called a siphon. Larvae of Coquillettidia and Mansonia possess modified siphons that allow them to pierce the stems of emergent vegetation in water and draw their oxygen from the plant in this process. Larvae are constantly feeding since maturation requires a huge amount of energy and food. They hang with their heads down and the brushes by their mouths filtering anything small enough to be eaten toward their mouths to nourish the growing larvae. They feed on algae, plankton, fungi and bacteria and other microorganisms. They breath at the water surface with the breathing tube up breaking the water surface tension. The larvae of a few mosquito species are cannibalistic, feeding on larvae of other mosquitoes: Toxorhynchites and some Psorophora, the largest mosquitoes known, are predators of other mosquito larvae sharing their habitat. Their larvae are much larger than other mosquito larvae.

During growth, the larva molts (sheds its skin) four times. The stages between molts are called instars. At the 4th instar, the usual larva reaches a length of almost 1/2 inch and toward the end of this instar ceases feeding. When the 4th instar larva molts, it becomes a pupa.

Mosquito Pupa

Mosquito pupae, commonly called "tumblers," live in water from 1 to 4 days, depending upon species and temperature.

The pupa is lighter than water and therefore floats at the surface. It takes oxygen through two breathing tubes called "trumpets." The pupa does not eat, but it is not an inactive stage. When disturbed, it dives in a jerking, tumbling motion toward protection and then floats back to the surface.

The metamorphosis of the mosquito into an adult is completed within the pupal case. The pupal case thus serves as a factory wherein the mosquito makes an adult out of a larva. The adult mosquito splits the pupal case and emerges to the surface of the water where it rests until its body dries and hardens.

Mosquito Adult

Only female mosquitoes require a blood meal and bite animals - warm or cold blooded - and birds. Stimuli that influence biting (blood feeding) include a combination of carbon dioxide, temperature, moisture, smell, color and movement. Male mosquitoes do not bite, but feed on the nectar of flowers or other suitable sugar source. Acquiring a blood meal (protein) is essential for egg production, but mostly both male and female mosquitoes are nectar feeders for their nutrition. Female Toxorhynchites actually can't obtain a bloodmeal and are restricted to a nectar diet. Of those female mosquitoes capable of blood feeding, human blood meals are seldom first or second choices. Horses, cattle, smaller mammals and/or birds are preferred.

Aedes and Ochlerotatus mosquitoes are painful and persistent biters.

They search for a blood meal early in the morning, at dusk (crepuscular feeders) and into the evening. Some are diurnal (daytime biters) especially on cloudy days and in shaded areas. They usually do not enter dwellings, and they prefer to bite mammals like humans. Aedes and Ochlerotatus mosquitoes are strong fliers and are known to fly many miles from their larval development sites.

Culex mosquitoes are painful and persistent biters also but prefer to attack at dusk and after dark. They readily enter dwellings for blood meals. Domestic and wild birds usually are preferred over man, cows, and horses. Culex nigripalpus is known to transmit St. Louis encephalitis to man in Florida. Culex mosquitoes are generally weak fliers and do not move far from home, although they have been known to fly up to two miles, Culex usually live only a few weeks during the warm summer months. Those females that emerge in late summer search for sheltered areas where they "hibernate" until spring. Warm weather brings them out again in search of water on which to lay their eggs.

Culiseta mosquitoes are moderately aggressive biters, attacking in the evening hours or in the shade during the day. Psorophora, Coquillettidia and Mansonia mosquitoes are becoming more pestiferous as an ever-expanding human population invades their natural habitats. Anopheles mosquitoes are persistent biters and are the only mosquitoes which transmit malaria to man.

Jai Ganesh · Science HQ

Nebulizer

Gist

A nebulizer is a medical device used to turn liquid medicine into a fine mist, allowing it to be easily inhaled deep into the lungs to treat respiratory conditions like asthma, COPD, cystic fibrosis, and bronchiectasis. It's especially helpful for people who have trouble using standard inhalers, delivering medication directly to the airways through a mouthpiece or mask over several minutes.

(COPD: Chronic Obstructive Pulmonary Disease)

According to the American College of Allergy, Asthma, and Immunology (ACAAI), nebulizers are often recommended for treating respiratory illnesses such as asthma, bronchitis, and chronic obstructive pulmonary disease (COPD), all of which may include chronic coughing as a symptom.

Summary:

What is a nebulizer?

A nebulizer changes liquid medicine into fine droplets (in aerosol or mist form) that are inhaled through a mouthpiece or mask. Nebulizers can be used to deliver many types of medicines. The medicines and moisture help control breathing problems like wheezing and help loosen lung secretions.

A nebulizer might be used instead of other inhalers. A nebulizer is powered by an air compressor that plugs into an electrical outlet.

What supplies do you need to use the nebulizer?

You will need the following supplies:

* Hand-held nebulizer.
* Air compressor.
* Mouthpiece or face mask.

Where should you use the nebulizer?

Use the nebulizer in a well-lighted area. Select a comfortable place in your home where you can take your treatment without being interrupted. Sit in a comfortable, straight-backed chair when taking your treatment.

Treatment procedure

* Place the compressor on a sturdy surface that will support its weight, such as a table or desk. Plug the compressor's cord into a properly grounded (three-pronged) outlet.
* Wash your hands with soap and water and dry completely with a clean towel.
* Become familiar with the nebulizer parts.
* Place your medication in the nebulizer cup.
* Attach the top portion of the nebulizer cup, and connect the mouthpiece or face mask to the cup.
* Connect the tubing to the nebulizer and compressor.
* Turn on the compressor with the on/off switch. Once you turn on the compressor, you should see a light mist.
* Sit up straight on a comfortable chair.
* Using a mouthpiece is preferred. When using a mouthpiece, place the mouthpiece between your teeth and seal your lips around it.
* If you are using a mask, position it comfortably and securely on your face.
* Breathe normally through your mouth. If possible, every fifth breath, take a slow deep breath and hold this breath for 2 to 3 seconds before breathing out. This allows the medication to settle into the airways.
* Continue the treatment until the medication is gone (about 5 to 15 minutes). Use all of the medicine unless you are directed otherwise by your doctor.
* If you become dizzy, slow your breathing or rest briefly. Some medicine may make you feel "jittery" or "shaky." This is not uncommon, but if these symptoms continue to bother you, inform your healthcare provider.
* Turn off the compressor.
* Wash your hands with warm water and soap. Dry them with a clean towel.

Care of nebulizer

Cleaning and disinfecting your equipment is simple, yet very important. After each treatment, rinse the nebulizer cup with warm water. Shake off excess water and let it air dry.

At the end of each day, the nebulizer cup, mask, or mouthpiece should be washed in warm, soapy water using a mild detergent. Rinse thoroughly, and allow to air dry. Note: There is no need to clean the tubing that connects the nebulizer to the air compressor.

Disinfect your nebulizer once per week or more frequently as directed. After washing your equipment, disinfect the nebulizer with one of the following methods.

Disposable nebulizers should use one of these cold disinfecting methods:

* Soak in 70% isopropyl alcohol for 5 minutes.
* Soak in 3% hydrogen peroxide for 30 minutes.
* Soak in a one-part white vinegar to 3-part water solution for 30 minutes.
* After any of these cold disinfecting techniques, rinse well and air dry.

Non-disposable nebulizers may be disinfected as described above. They may also be disinfected by any of the following heat disinfecting methods:

* Boil for 5 minutes.
* Microwave in a bowl of water for 5 minutes.
* Put in the dishwasher at 158 degrees Fahrenheit for 30 minutes.
* Use an electric steam sterilizer (baby bottle sterilizer).

Medicine storage

Store all of your medicines in a cool, dry place, and follow the manufacturer’s recommendations.

Check your medicines often. Make sure they have not changed color or formed crystals. If you notice any changes in the appearance of your medicines, throw them away.

Compressor care

* Make sure that your unit is unplugged before you clean it. Keep your air compressor clean by wiping it with a clean damp cloth as needed.
* Do not put the air compressor on the floor during your treatments or while storing.
* Check the air compressor’s filter as directed. Replace or clean or clean the filter according to the directions from your equipment supplier.
* Always have an extra nebulizer cup and mask or mouthpiece.
* You can obtain all of the equipment for your nebulizer therapy through your equipment supplier.

Details

In medicine, a nebulizer (American English) or nebuliser (English) is a drug delivery device used to administer medication in the form of a mist inhaled into the lungs. Nebulizers are commonly used for the treatment of asthma, cystic fibrosis, COPD and other respiratory diseases or disorders. They use oxygen, compressed air or ultrasonic power to break up solutions and suspensions into small aerosol droplets that are inhaled from the mouthpiece of the device. An aerosol is a mixture of gas and solid or liquid particles.

Medical uses:

Guidelines

Various asthma guidelines, such as the Global Initiative for Asthma Guidelines [GINA], the British Guidelines on the management of Asthma, The Canadian Pediatric Asthma Consensus Guidelines, and United States Guidelines for Diagnosis and Treatment of Asthma each recommend metered dose inhalers in place of nebulizer-delivered therapies. The European Respiratory Society acknowledge that although nebulizers are used in hospitals and at home they suggest much of this use may not be evidence-based.

Effectiveness

Recent evidence shows that nebulizers are no more effective than metered-dose inhalers (MDIs) with spacers. An MDI with a spacer may offer advantages to children who have acute asthma. Those findings refer specifically to the treatment of asthma and not to the efficacy of nebulisers generally, as for COPD for example. For COPD, especially when assessing exacerbations or lung attacks, there is no evidence to indicate that MDI (with a spacer) delivered medicine is more effective than administration of the same medicine with a nebulizer.

The European Respiratory Society highlighted a risk relating to droplet size reproducibility caused by selling nebulizer devices separately from nebulized solution. They found this practice could vary droplet size 10-fold or more by changing from an inefficient nebulizer system to a highly efficient one. Two advantages attributed to nebulizers, compared to MDIs with spacers (inhalers), are their ability to deliver larger dosages at a faster rate, especially in acute asthma; however, recent data suggests actual lung deposition rates are the same. In addition, another trial found that an MDI (with spacer) had a lower required dose for clinical result compared to a nebulizer.

Beyond use in chronic lung disease, nebulizers may also be used to treat acute issues like the inhalation of toxic substances. One such example is the treatment of inhalation of toxic hydrofluoric acid (HF) vapors. Calcium gluconate is a first-line treatment for HF exposure to the skin. By using a nebulizer, calcium gluconate is delivered to the lungs as an aerosol to counteract the toxicity of inhaled HF vapors.

Aerosol deposition

The lung deposition characteristics and efficacy of an aerosol depend largely on the particle or droplet size. Generally, the smaller the particle the greater its chance of peripheral penetration and retention. However, for very fine particles below 0.5 μm in diameter there is a chance of avoiding deposition altogether and being exhaled. In 1966 the Task Group on Lung Dynamics, concerned mainly with the hazards of inhalation of environmental toxins, proposed a model for deposition of particles in the lung. This suggested that particles of more than 10 μm in diameter are most likely to deposit in the mouth and throat, for those of 5–10 μm diameter a transition from mouth to airway deposition occurs, and particles smaller than 5 μm in diameter deposit more frequently in the lower airways and are appropriate for pharmaceutical aerosols. Nebulizing processes have been modeled using computational fluid dynamics.

Additional Information

There are different types of medicines and delivery devices to treat COPD. A nebulizer is a device that turns the liquid medicine into a mist which is then inhaled through a mouthpiece or a mask. Sometimes asthma medication is given through a nebulizer as well, so this information can benefit people living with asthma too. With COPD, or any chronic lung disease, taking your medicine correctly is a major part in successfully managing the disease.

Learning how to use your nebulizer and clean it properly is important so that your medications are most effective. These videos offer a step-by-step guide to cleaning and using medications correctly.

How to Use a Nebulizer

Many people with chronic lung diseases such as COPD or asthma use a nebulizer to take their medication in the form of a mist that is inhaled into the lungs.

Nebulizers are often recommended for patients who have a hard time using inhalers because of health issues, or patients who are unable to inhale deeply enough for other devices.

A nebulizer has five basic parts A medicine cup, a top piece or cap to attach to a mask or mouthpiece to the medicine cup.

With your healthcare provider, you can decide which type works best for you. thin plastic tubing connects the mouthpiece to the machine and an air machine called a compressor, which can be plugged into an electrical socket for indoor use, a car adapter for when you are on the go, or battery-operated for portable use while not at home.

With clean hands, take the medicine as prescribed by your healthcare provider, and pour it into the medicine cup. Attach the top piece to the medicine cup, and then the mouthpiece or mask. Connect the tubing from the compressor to the medicine cup.

Put the mask over your face, or put the mouthpiece in your mouth between your teeth, and close your lips tightly around it. Turn on your compressor. Hold the nebulizer in an upright position to prevent spilling and to ensure the medication is correctly distributed.

Take normal regular breaths in through your mouth so that the medicine can go deep into your lungs. Continue until all of the medicine is gone from the cup. For more demonstration videos and information on cleaning and caring for your nebulizer, visit the American Lung Association's website at Lung.org/nebulizer.

How to Clean a Nebulizer

Many people with chronic lung diseases such as COPD or asthma use a nebulizer to take their medication in the form of a mist that is inhaled into the lungs.

Cleaning your nebulizer is important to prevent the spread of germs and keep you from getting sick. It will also keep your device working properly. It is recommended to wash the parts of your nebulizer after each use, including the mouthpiece or mask, top piece, and medicine cup.

To start, take the nebulizer apart by removing the tubing and setting it aside.

The tubing should never be placed under water. Remove the mouthpiece or mask, and medicine cup from the top piece, and place them all into the top shelf of the dishwasher.

Or wash the medicine cup, top piece, and mouthpiece or mask, in warm soapy water, and rinse. Shake off the excess water and let the pieces air-dry in a cool, dry place until the next use.

Your nebulizer will also need a thorough cleaning once a week. Soak the mouthpiece or mask, top piece, and medicine cup in a white vinegar and water solution for 30 minutes, or as recommended by your device manufacturer.

After 30 minutes, rinse and air-dry in a cool, dry place.

Clean the surface of the compressor and the outside of the tubing with a soapy cloth or disinfectant wipe.

The compressor and the tubing should never be submerged in water.

And remember, most compressors have an air filter that will need to be replaced every six months, or as recommended by your manufacturer.

Jai Ganesh · Dark Discussions at Cafe Infinity

2410) Francis Crick

Gist:

Work

In 1944, Oswald Avery proved that DNA is the bearer of organisms' genetic code. Further explanation was provided when Francis Crick and James Watson determined the structure of the DNA molecule in 1953. This structure–a long double helix–contains a long row of pairs of four different nitrogen bases, which allow the molecule to function like a code. The molecule's structure also explains how it is able to copy itself. The nitrogen bases always pair in the same constellations, so that if a molecule is split, its halves can be supplemented so that they form copies of the original molecule.

Summary

Francis Harry Compton Crick (8 June 1916 – 28 July 2004) was an English molecular biologist, biophysicist, and neuroscientist. He, James Watson, Rosalind Franklin, and Maurice Wilkins played crucial roles in deciphering the helical structure of the DNA molecule.

Crick and Watson's paper in Nature in 1953 laid the groundwork for understanding DNA structure and functions. Together with Maurice Wilkins, they were jointly awarded the 1962 Nobel Prize in Physiology or Medicine "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material".

Crick was an important theoretical molecular biologist and played a crucial role in research related to revealing the helical structure of DNA. He is widely known for the use of the term "central dogma" to summarise the idea that once information is transferred from nucleic acids (DNA or RNA) to proteins, it cannot flow back to nucleic acids. In other words, the final step in the flow of information from nucleic acids to proteins is irreversible.

During the remainder of his career, Crick held the post of J.W. Kieckhefer Distinguished Research Professor at the Salk Institute for Biological Studies in La Jolla, California. His later research centred on theoretical neurobiology and attempts to advance the scientific study of human consciousness. Crick remained in this post until his death in 2004; "he was editing a manuscript on his death bed, a scientist until the bitter end" according to Christof Koch.

Details

Francis Crick (born June 8, 1916, Northampton, Northamptonshire, England—died July 28, 2004, San Diego, California, U.S.) was a British biophysicist, who, with James Watson and Maurice Wilkins, received the 1962 Nobel Prize for Physiology or Medicine for their determination of the molecular structure of deoxyribonucleic acid (DNA), the chemical substance ultimately responsible for hereditary control of life functions. This accomplishment became a cornerstone of genetics and was widely regarded as one of the most important discoveries of 20th-century biology.

During World War II, Crick interrupted his education to work as a physicist in the development of magnetic mines for use in naval warfare, but afterward he turned to biology at the Strangeways Research Laboratory, University of Cambridge (1947). Interested in pioneering efforts to determine the three-dimensional structures of large molecules found in living organisms, he transferred to the university’s Medical Research Council Unit at the Cavendish Laboratories in 1949.

In 1951, when the American biologist James Watson arrived at the laboratory, it was known that the mysterious nucleic acids, especially DNA, played a central role in the hereditary determination of the structure and function of each cell. Watson convinced Crick that knowledge of DNA’s three-dimensional structure would make its hereditary role apparent. Using the X-ray diffraction studies of DNA done by Wilkins and X-ray diffraction pictures produced by Rosalind Franklin, Watson and Crick were able to construct a molecular model consistent with the known physical and chemical properties of DNA. The model consisted of two intertwined helical (spiral) strands of sugar-phosphate, bridged horizontally by flat organic bases. Watson and Crick theorized that if the strands were separated, each would serve as a template (pattern) for the formation, from small molecules in the cell, of a new sister strand identical to its former partner. This copying process explained replication of the gene and, eventually, the chromosome, known to occur in dividing cells. Their model also indicated that the sequence of bases along the DNA molecule spells some kind of code “read” by a cellular mechanism that translates it into the specific proteins responsible for a cell’s particular structure and function.

By 1961 Crick had evidence to show that each group of three bases (a codon) on a single DNA strand designates the position of a specific amino acid on the backbone of a protein molecule. He also helped to determine which codons code for each of the 20 amino acids normally found in protein and thus helped clarify the way in which the cell eventually uses the DNA “message” to build proteins. From 1977 until his death, Crick held the position of distinguished professor at the Salk Institute for Biological Studies in San Diego, California, where he conducted research on the neurological basis of consciousness. His book Of Molecules and Men (1966) discusses the implications of the revolution in molecular biology. What Mad Pursuit: A Personal View of Scientific Discovery was published in 1988. In 1991 Crick received the Order of Merit.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#5895. What does the noun lavender mean?

#5896. What does the adjective lavish mean?

Jai Ganesh · This is Cool

2470) Atlas Mountains

Gist

The Atlas Mountains are a major North African range spanning Morocco, Algeria, and Tunisia, forming a natural barrier between the Mediterranean/Atlantic coasts and the Sahara Desert, with the highest peak, Toubkal (4,167m), in Morocco, and are home to indigenous Berber populations and unique ecosystems. This extensive system is divided into several sub-ranges, like the High Atlas, Middle Atlas, and Anti-Atlas, known for their rugged terrain, traditional villages, and biodiversity.

The Atlas Mountains also have a diverse ecosystem and support a variety of flora and fauna. The lower slopes are covered in oak and cedar forests, while higher elevations feature alpine meadows. There are over 150 flower species, some 50 of which are endemic.

Summary

The Atlas Mountains are a mountain range in northwest Africa. They extend about 2,400 km (1,500 miles) through Morocco, Algeria, and Tunisia. The highest peak is Toubkal, with an elevation of 4,167 metres (13,671 ft) in southwestern Morocco. The second highest mountain is the M'Goun of 4071 meters. The southwestern part is called "Anti-Atlas".

The Atlas ranges separate the Mediterranean and Atlantic coastlines from the Sahara Desert. Most of the people living in the Atlas Mountains are part of Berber tribes in Morocco and in Algeria.

The mountains are named after the ancient Greek Titan, Atlas.

Details

The Atlas Mountains are a mountain range in the Maghreb in North Africa. They separate the Sahara Desert from the Mediterranean Sea and the Atlantic Ocean; the mountain range stretches around 2,500 km (1,600 mi) through Morocco, Algeria and Tunisia. The mountains are associated with the Titan Atlas. The range's highest peak is Toubkal, in central Morocco, with an elevation of 4,167 metres (13,671 ft). The Atlas Mountains are primarily inhabited by Berber populations.

The terms for 'mountain' are Adrar and adras in some Berber languages, and these terms are believed to be cognates of the toponym Atlas. The mountains are home to a number of animals and plants which are mostly found within Africa but some of which can be found in Europe. Many of these species are endangered and a few are already extinct. The weather is generally cool but summers are sunny, and the average temperature there is 25 °C.

Geology

The basement rock of most of Africa was formed during the Precambrian supereon and is much older than the Atlas Mountains lying on the continent. The Atlas was formed during three subsequent phases of Earth's geology.

The first tectonic deformation phase involves only the Anti-Atlas, which was formed in the Paleozoic Era (~300 million years ago) as the result of continental collisions. North America, Europe and Africa were connected millions of years ago.

The Anti-Atlas Mountains are believed to have originally been formed as part of the Alleghenian orogeny. These mountains were formed when Africa and America collided and were once a chain rivaling today's Himalayas. Today, the remains of this chain can be seen in the Fall Line region in the Eastern United States. Some remnants can also be found in the later formed Appalachians in North America.

A second phase took place during the Mesozoic Era (before ~66 My). It consisted of a widespread extension of the Earth's crust that rifted and separated the continents mentioned above. This extension was responsible for the formation of many thick intracontinental sedimentary basins including the present Atlas. Most of the rocks forming the surface of the present High Atlas were deposited under the ocean at that time.

In the Paleogene and Neogene Periods (~66 million to ~1.8 million years ago), the mountain chains that today constitute the Atlas were uplifted, as the land masses of Europe and Africa collided at the southern end of the Iberian Peninsula. Such convergent tectonic boundaries occur where two plates slide towards each other forming a subduction zone (if one plate moves underneath the other), and/or a continental collision (when the two plates contain continental crust). In the case of the Africa-Europe collision, it is clear that tectonic convergence is partially responsible for the formation of the High Atlas, as well as for the closure of the Strait of Gibraltar and the formation of the Alps and the Pyrenees.

However, there is a lack of evidence for the nature of the subduction in the Atlas region, or for the thickening of the Earth's crust generally associated with continental collisions. One of the most striking features of the Atlas to geologists is the relatively small amount of crustal thickening and tectonic shortening despite the important altitude of the mountain range. Recent studies suggest that deep processes rooted in the Earth's mantle may have contributed to the uplift of the High and Middle Atlas.

Natural resources

The Atlas are rich in natural resources. There are deposits of iron ore, lead ore, copper, silver, mercury, rock salt, phosphate, marble, anthracite coal and natural gas among other resources.

Additional Information

Atlas Mountains, series of mountain ranges in northwestern Africa, running generally southwest to northeast to form the geologic backbone of the countries of the Maghrib (the western region of the Arab world)—Morocco, Algeria, and Tunisia. They extend for more than 1,200 miles (2,000 kilometres), from the Moroccan port of Agadir in the southwest, to the Tunisian capital of Tunis in the northeast. Their thick rim rises to form a high sill separating the Mediterranean basin to the north from the Sahara to the south, thus constituting a barrier that hinders, without completely preventing, communication between the two regions. Across the mountains filter both air masses and human migrations. It is, however, only in the east–west direction that the Atlas Mountains facilitate movement. These are the conditions that create at the same time both the individuality and the homogeneity of the Atlas countries. Although the Saharan region is more likely to be described as the archetypal North African habitat, it is the well-watered mountains north of this vast desert that provide the foundation for the livelihood of most of the peoples of North Africa and a striking green or white background for many North African towns.

Physical features:

Physiography

The Atlas mountain system takes the shape of an extended oblong, enclosing within its ranges a vast complex of plains and plateaus.

The northern section is formed by the Tell Atlas, which receives enough rainfall to bear fine forests. From west to east several massifs (mountainous masses) occur. The first of these is Er-Rif, which forms a half-moon-shaped arc in Morocco between Ceuta and Melilla; its crest line exceeds 5,000 feet (1,500 metres) above sea level at several points, reaching 8,058 feet at Mount Tidirhine. East of the gap formed by the Moulouya River the Algerian ranges begin, among which the rugged bastion of the Ouarsenis Massif (which reaches a height of 6,512 feet), the Great Kabylie, which reaches 7,572 feet at the peak of Lalla Khedidja, and the mountains of Kroumirie in Tunisia are all prominent.

The southern section, which is subject to desert influences, is appropriately called the Saharan Atlas. It includes in the centre a palisade formed by shorter ranges, such as the Ksour and Ouled-Naïl mountains, grouped into massifs between two mighty ranges—the Moroccan High Atlas to the west and the Aurès Mountains to the east. The High Atlas culminates in Mount Toubkal at 13,665 feet (4,165 metres), the highest point in the Atlas Mountains, which is surrounded by high snowcapped peaks; the Aurès Mountains are formed of long parallel folds, which reach a height of 7,638 feet at Mount Chelia.

The Tell Atlas and the Saharan Atlas merge in the west into the long folds of the Middle Atlas and in the east join together in the Tébessa and Medjerda mountains.

Geology

If the relief of the Atlas region is relatively simple, its geology is complex. In essence, the two Atlases comprise two different structural regions.

The Tell Atlas originally arose out of a basin filled with sediment, which was dominated to the north by a marginal rim, of which the massifs of Tizi Ouzou, Collo, and Edough are the remnants. Its elevation took place during a lengthy mountain-building process that was marked by upheavals in the Paleogene and Neogene periods (i.e., about 65 to 2.6 million years ago); over the cluster of folds that were uplifted from the rift valley were spread sheets of flysch (deposits of sandstones and clays), which were carried down from the north over the top of the marginal rim. Thus the Tell Atlas represents an example of a young folded mountain range still in the process of formation, as is shown by the earth tremors to which it is subject.

To the south the Saharan Atlas belongs to another structural grouping, that of the vast plateaus of the African continent, which form part of the ancient base rock largely covered by sediments deposited by shallow seas and by alluvial deposits. The Saharan Atlas is the result either of the mighty folding of the substructure that raised up fragments of the base rock—such as the horst (uplifted block of the Earth’s crust), which constitutes the Moroccan High Atlas—or else of the crumpling into folds of the Earth’s crust during the Jurassic Period (about 200 to 145 million years ago) and the Cretaceous Period (about 145 to 65 million years ago).

Drainage

The seasonal character of the rains, which fall in torrents, determines the characteristics of drainage in the Atlas: the runoff feeds streams that are of great erosive capacity and that have cut their way down through the thickness of accumulated layers of sediment to form deep narrow gorges difficult to cross. The pre-Roman fortress of Cirta (now called Constantine) in Algeria stands on a rock sculptured out by one such stream, the winding Rhumel River.

The great Maghribian wadis (French: oueds; channels of watercourses that are dry except during periods of rain) issue from the Atlas ranges. Among the more perennial rivers are the Moulouya, which rises from the Middle Atlas, and the Chelif, which rises from the Amour Mountains. Destructive of the soils of their headstreams, they deposit their loads of silt at the foot of the mountain ranges or else leave a long line of conical deposits locally known as dirs (“hills”).

Soils

Good soil is sparse at higher altitudes in the Atlas region. Most often nothing is to be found but bare rock, debris, and fallen materials incessantly renewed by landslides. Two materials predominate—limestone, which forms ledges that are half-buried in rough debris, and marls (chalky clays) cut by erosion into a maze of ravines and crumbling gullies. The rarer sandstones favour forest growth. The best soils are the alluvia found on the terraced slopes and on the valley bottoms.

Climate of the Atlas Mountains

The Atlas Mountains are the meeting place of two different kinds of air masses—the humid and cold polar air masses that come from the north and the hot and dry tropical air masses that move up from the south. To the influences of altitude and latitude must be added that of aspect or exposure.

Rain is more plentiful in the Tell Atlas than in the Saharan Atlas, and more so to the northeast than to the southwest: the highest rainfall is recorded east of the Tell Atlas. ʿAyn ad-Darāhim in the Kroumirie mountains receives 60 inches (1,524 millimetres) a year; nowhere in the Anti-Atlas Mountains, south of the High Atlas, is the total more than 17 inches a year. In a single massif the slopes with a northern exposure receive more rainfall than those with a southern exposure.

With increased altitude the temperature drops rapidly; despite the proximity of the sea, the coastal massifs are cold regions. At 6,575 feet the summits of Mount Babor in the Little Kabylie region are covered with snow for four or five months, while the Moroccan High Atlas retains its snows until the height of summer. Winter in the Atlas is hard, imposing severe conditions upon the inhabitants.

Plant and animal life

Erosion of the soils in the Atlas region is aggravated by the sparseness of the vegetation covering the landscape; only about 39,000 square miles (101,000 square kilometres) of land are forested. On Er-Rif and the Kabylie and Kroumirie ranges, which experience some rainfall, moist forests of cork oaks cover an undergrowth of arbutus (cane apple) and heather shrub, and carpets of rockroses and lavender are found. When the total annual rainfall is less than about 30 inches and limestone is present, green oak and arborvitae (a species of pine tree) cover the soil, forming light, dry forests with a thin and bushy undergrowth. Stands of cedar predominate at higher altitudes. On the dry summits of the Saharan Atlas the vegetation is reduced to scattered stands of green oak and juniper trees.

The clearance of land for agriculture has reduced the forest cover in the Atlas ranges; animal life in the mountains is also in retreat. There remain only a few jackals, some tribes of monkeys (Barbary apes) at higher elevations, and occasional herds of wild boars in the oak woods.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#10699. What does the term in Geography Continental divide mean?

#10700. What does the term in Geography Continental shelf mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#2544. What does the medical term Myotonic dystrophy mean?

Jai Ganesh · Science HQ

Chemotherapy

Gist

Chemotherapy (often called "chemo") is a type of cancer treatment that uses powerful anti-cancer drugs to destroy fast-growing cells in the body. The goal can be to cure the cancer, control its growth, or ease symptoms.

Chemotherapy itself isn't usually painful during administration (pills, IVs), but the process can cause discomfort from needle sticks, and the drugs often lead to painful side effects like mouth sores, nerve pain (neuropathy), headaches, and body aches, which are manageable with medications and support. Pain levels vary greatly, but reporting any discomfort to your medical team is key, as they can offer relief through anti-nausea meds, pain relievers, or other strategies like acupuncture and massage.

Summary

Chemotherapy is the treatment of diseases by chemical compounds. Chemotherapeutic drugs were originally those employed against infectious microbes, but the term has been broadened to include anticancer and other drugs.

Until the end of the 19th century, most drugs were derived either from minerals or from plants. The researches of Louis Pasteur in France and Robert Koch in Germany laid the foundations of bacteriology. It was Paul Ehrlich, however, who made the greatest contribution to the science (chemotherapy) he named. The problem facing medical scientists was to produce a disinfectant that would destroy parasites within a living animal without serious damage to the host.

William H. Perkin, in England, made the first aniline dye (1856) as a result of abortive attempts to synthesize quinine, the sole antimalarial drug available at that time. About 30 years later, Ehrlich found that a synthetic dye, methylene blue, has antimalarial properties. He had been led to this by a study of the specific staining of organs of an animal or of a parasite following the injection of a synthetic dye. From these studies there emerged (1901–04) Ehrlich’s well-known “side-chain” theory, in which he sought for the first time to correlate the chemical structure of a synthetic drug with its biological effects. In 1903 Ehrlich invented a dye, trypan red, which was the first drug to show activity against trypanosomal infections in mice. Ehrlich’s greatest triumph, however, was the discovery (1910) of the organic math drug Salvarsan, which proved to be effective in the treatment of syphilis. The discovery of other chemotherapeutic agents followed, including mepacrine, proguanil, and chloroquine.

The discovery of Prontosil in the early 1930s proved that antibacterial agents could be developed. Prontosil was the forerunner of the sulfonamide drugs, which came to be widely used for the treatment of bacterial infections in humans and domestic animals.

The discovery of penicillin by Sir Alexander Fleming in 1928, and its practical development by Sir Howard Florey and Ernst Chain, marked another important advance in bacterial chemotherapy. Penicillin, which did not become widely used until World War II, was the first of the so-called antibiotics, and it was followed by other important antibiotics such as streptomycin, the tetracyclines, and the macrolides.

Antibiotics, whether they are produced by living organisms (usually fungi or bacteria) or artificially synthesized, have transformed the modern management of diseases caused by bacteria and most other microorganisms. Paradoxically, the more widely they are used, the greater the likelihood that drug-resistant bacteria will emerge. Bacteria may develop resistance to drugs in several ways: mutation changes in genetic composition; transduction, whereby resistance is transferred from a resistant to a nonresistant strain; transformation, in which a bacterial cell takes from its environment the genes from a resistant form to acquire resistance; and conjugation, in which the organism acquires resistance by cell-to-cell contact.

Another comparative failure of chemotherapy is the lack of drugs to combat viruses (although viral infections can be controlled through prophylactic measures).

Drug modes of action vary. For example, some may act on the bacterial wall, others affect cell membranes, some modify the molecular mechanism for duplication, some change the nucleic acid metabolism, and others change the intermediary metabolism of two interacting organisms.

Cancer chemotherapy is an increasingly important aspect of drug treatment. Alkylating agents (that work by impairing cell division) and antimetabolites (that interfere with enzymes and thus block vital cell processes) are used cytotoxically to attack malignant cells. Steroid hormones are used in the treatment of breast and prostate cancers, and corticosteroids are used to treat leukemia and lymphatic cancers. The periwinkle plant derivatives vincristine and vinblastine have been used effectively in treating Hodgkin’s disease and leukemia.

The alkylating agents and antimetabolites have serious drawbacks. As they cannot distinguish between healthy and malignant cells, these drugs also interfere with actively multiplying noncancerous cells. They also reduce the body’s resistance to infection. Work is being done on tumour-specific agents that attack only cancer cells.

Another area where chemotherapy has had a major, albeit controversial, impact is mental illness. Severe depression, anxiety, and schizophrenia are now treated with various drugs.

Concomitant with the successes of drug therapy has come increasing concern about attendant dangers. Stringent controls are operated by such regulatory agencies as the Food and Drug Administration in the United States and the Committee on Safety of Medicines in the United Kingdom. These bodies ensure the safety of pharmaceuticals before they are placed on the market and monitor any side effects thereafter. Public demands for “watchdog” agencies were triggered in large part by the 1962 Thalidomide tragedy, when thousands of severely deformed children were born to users of that insufficiently tested drug.

Details

Chemotherapy (often abbreviated chemo, sometimes CTX and CTx) is the type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) in a standard regimen. Chemotherapy may be given with a curative intent (which almost always involves combinations of drugs), or it may aim only to prolong life or to reduce symptoms (palliative chemotherapy). Chemotherapy is one of the major categories of the medical discipline specifically devoted to pharmacotherapy for cancer, which is called medical oncology.

The term chemotherapy now means the non-specific use of intracellular poisons to inhibit mitosis (cell division) or to induce DNA damage (so that DNA repair can augment chemotherapy). This meaning excludes the more-selective agents that block extracellular signals (signal transduction). Therapies with specific molecular or genetic targets, which inhibit growth-promoting signals from classic endocrine hormones (primarily estrogens for breast cancer and androgens for prostate cancer), are now called hormonal therapies. Other inhibitions of growth-signals, such as those associated with receptor tyrosine kinases, are targeted therapy.

The use of drugs (whether chemotherapy, hormonal therapy, or targeted therapy) is systemic therapy for cancer: they are introduced into the blood stream (the system) and therefore can treat cancer anywhere in the body. Systemic therapy is often used with other, local therapy (treatments that work only where they are applied), such as radiation, surgery, and hyperthermia.

Traditional chemotherapeutic agents are cytotoxic by means of interfering with cell division (mitosis) but cancer cells vary widely in their susceptibility to these agents. To a large extent, chemotherapy can be thought of as a way to damage or stress cells, which may then lead to cell death if apoptosis is initiated. Many of the side effects of chemotherapy can be traced to damage to normal cells that divide rapidly and are thus sensitive to anti-mitotic drugs: cells in the bone marrow, digestive tract and hair follicles. This results in the most common side-effects of chemotherapy: myelosuppression (decreased production of blood cells, hence that also immunosuppression), mucositis (inflammation of the lining of the digestive tract), and alopecia (hair loss). Because of the effect on immune cells (especially lymphocytes), chemotherapy drugs often find use in a host of diseases that result from harmful overactivity of the immune system against self (so-called autoimmunity). These include rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, vasculitis and many others.

Additional Information

Chemotherapy (chemo) is one of the most common treatments for cancer. Learning about how it works and what to expect can help you prepare for treatment and make informed decisions about your care.

What is chemotherapy?

Chemotherapy is a treatment that uses medicines to destroy cancer cells. There are many different types of chemo. They don’t all work exactly the same way, so different types of chemo might be used for different types of cancer. Most are given as an infusion into a vein (IV), but some are given as an injection, taken as pills, or applied to the skin.

What is the goal of chemo?

If your doctor has recommended chemo, it’s important to understand the goal of treatment. This can depend on your type of cancer, its stage (size and location), and how far it has spread. Chemo can have 3 possible treatment goals:

* To cure the cancer (curative intent)
* To control the cancer
* To ease symptoms (palliative intent)

How is chemo different from other cancer treatments?

Chemo is a systemic treatment. It travels through the bloodstream to reach all parts of your body. It can kill cancer cells that have spread (metastasized) to parts of the body far away from the original (primary) tumor or cancer cells in blood cancers, such as leukemia, that have spread throughout the body. This makes chemo different from local treatments like surgery and radiation, which only affect one part of the body.

How does chemotherapy work?

Understanding how chemotherapy works can help you know what to expect during treatment.

Chemotherapy interrupts the cell cycle

Chemotherapy works by affecting cells when they are growing and dividing to make new cells. During this process (called the cell cycle), cells:

* Grow in size
* Make copies of their genetic material (DNA)
* Divide to form new cells

Some cells, such as skin cells, are fast growing, meaning they move through this process quickly. Other cells, such as muscle cells, complete it more slowly. Cancer cells tend to be faster growing, moving through the cell cycle very quickly.

Different types of chemo target cells at different phases of the cell cycle. This is why certain chemo drugs work better for different types of cancer cells, and sometimes different combinations of chemo work better together. Understanding how chemo works also helps doctors plan how often each chemo should be given, and how those doses should be timed.

Chemo affects normal cells, too

Chemo interrupts the cell cycles of normal cells, too – especially cells that grow faster, like hair or skin cells. This is why chemo often causes certain side effects, like hair loss.

The good news is that most normal cells will recover from chemo. Chemo is a useful cancer treatment because cancer cells are abnormal (mutated) and less able to recover from its effects.

To work best, chemo treatments must be at just the right dose to kill the cancer cells while sparing as many normal cells as possible.

Are all medicines used to treat cancer called chemo?

Not all cancer medicines are chemotherapy. Other medicines and biological treatments may be used alone or with chemo or other treatments. They work differently and often have different side effects.

* Targeted therapy: These find and attack specific proteins or receptors that some cancer cells have, without affecting most normal cells.
* Hormone therapy: These block or lower hormones that help some cancers (like breast, prostate, and endometrial (uterine) cancers) grow. They either stop the body from making the hormone or block the cancer cells from using it.
* Immunotherapy: These help a person's immune system recognize and attack certain types of cancer cells.

Although these treatments can be very effective, they are more specialized than traditional chemo. They might only work on certain types of cancer, often based on specific traits of the cancer cells. And because many of them are newer, less is known about their long-term side effects. Sometimes they are used only when chemo isn’t working or is no longer effective.

What is it like to get chemo?

Most people get chemo as infusions at a clinic or hospital. But some types of chemo can be taken by mouth or applied to the skin at home. Each type has its own routine, side effects, and safety steps. Learn what it’s like to get each type of chemo and how to stay safe during treatment.

Jai Ganesh · Dark Discussions at Cafe Infinity

Collectively Quotes

1. I never did anything alone. Whatever was accomplished in this country was accomplished collectively. - Golda Meir

2. And I believe we should strengthen unions which have formed the bedrock of a strong middle class. It should be easier to bargain collectively. That's not only fair, it makes workers more productive, it strengthens our economy. - Hillary Clinton

3. An economically peaceful and prosperous Sri Lanka is the dream of youth of the nation. My message for the youth is to collectively work for an inclusively developed Sri Lanka. - A. P. J. Abdul Kalam

4. I even get inspired by movies that aren't very good, because there's always something good in movies that are collectively thought of as a failure. There's good in everything, I find. - Steven Spielberg

5. I have a lot of wonderful people in my life - probably five, collectively - who I can tell everything to. - Selena Gomez

6. Isolated decisions, however well-founded they might seem to the individual, and national go-it-alone moves must belong to the past. They should not be the 21st-century method of choice, particularly because the consequences of the European community's actions must often be carried collectively. - Helmut Kohl

7. Cancer treatment is very expensive, and the process is painful and long. This is something that we have to collectively think about, on how to make it affordable. - Manisha Koirala.

Jai Ganesh · Jokes

Q: What Welsh cheese must you always eat with caution?
A: Caerphilly.
* * *
Q: What do you call a cheese that is an alcoholic?
A: Livarot.
* * *
Q: What is a lions favourite cheese?
A: Roar-quefort.
* * *
Q: What did the piece of Cheddar say to the ghost?
A: I'm Lac-ghost intolerant.
* * *
Q: Why did the one legged clown leave the cheese circus?
A: Because he couldn't get his stilton.
* * *

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#9828.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#6322.

Jai Ganesh · Exercises

Hi,

2679.

Math Is Fun Forum

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#21 Dark Discussions at Cafe Infinity » Collectively Quotes » 2026-01-05 17:09:35

#22 Jokes » Cheese Jokes - IV » 2026-01-05 16:29:39

#23 Re: Jai Ganesh's Puzzles » 10 second questions » 2026-01-05 16:10:48

#24 Re: Jai Ganesh's Puzzles » Oral puzzles » 2026-01-05 15:57:02

#25 Re: Exercises » Compute the solution: » 2026-01-05 15:26:39

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