Posts by Jai Ganesh

Jai Ganesh · This is Cool

2485) Seychelles

Gist

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

Summary

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

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

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

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

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

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

Details:

Ethnic groups, languages, and religion

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

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

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

Settlement patterns and demographic trends

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

Economy

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

Agriculture, forestry, and fishing

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

Manufacturing, finance, and trade

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

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

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

Services

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

Transportation and telecommunications

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

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

Jai Ganesh · Dark Discussions at Cafe Infinity

2423) Jaroslav Heyrovský

Gist:

Work

Chemical and electrical phenomena are often associated, as in the case of redox reactions, when electrons are emitted and absorbed. In 1922 Jaroslav Heyrovsky discovered a method for analyzing the occurrence and content of various substances in solutions using electrical measurements. The solution is analyzed with two electrodes, one of which is a dropping mercury electrode. At a voltage specific for different substances, redox reactions cause the current to rapidly increase to a level dependent on the concentration of the substance.

Summary

Jaroslav Heyrovský (born December 20, 1890, Prague, Bohemia, Austro-Hungarian Empire [now in Czech Republic]—died March 27, 1967, Prague, Czechoslovakia) was a Czech chemist who received the Nobel Prize for Chemistry in 1959 for his discovery and development of polarography.

Educated at the Charles University (Universita Karlova) of Prague and at University College, London, Heyrovský worked in London under Sir William Ramsay and F.G. Donnan. After holding several posts at the Charles University, he became professor and director of the department of physical chemistry (1926–54), and he was director of the Polarography Institute at the Czechoslovak Academy of Sciences (1950, 1952–63).

The work that eventually led to the discovery of polarography was begun in London at Donnan’s suggestion. Polarography is an instrumental method of chemical analysis used for qualitative and quantitative determinations of reducible or oxidizable substances. Heyrovský’s instrument measures the current that flows when a predetermined potential is applied to two electrodes immersed in the solution to be analyzed. Within 10 years of the demonstration of the first polarograph (1924) the method was in common use. Heyrovský’s monograph Polarographie appeared in 1941.

Details

Jaroslav Heyrovský (20 December 1890 – 27 March 1967) was a Czech chemist and inventor who received the Nobel Prize in Chemistry in 1959 for his invention of polarography.

Life and work

Jaroslav Heyrovský was born in Prague on 20 December 1890, the fifth child of Leopold Heyrovský, Professor of Roman Law at the Charles University in Prague, and his wife Clara, née Hanl von Kirchtreu. He obtained his early education at secondary school until 1909 when he began his study of chemistry, physics, and mathematics at the Charles University in Prague. From 1910 to 1914 he continued his studies at University College London, under Professors Sir William Ramsay, W. C. McC. Lewis, and F. G. Donnan, taking his B.Sc. degree in 1913. He was particularly interested in working with Professor Donnan, on electrochemistry.

During the First World War Heyrovský worked in a military hospital as a dispensing chemist and radiologist, which enabled him to continue his studies and to take his Ph.D. degree in Prague in 1918 and D.Sc. in London in 1921.

Heyrovský started his university career as assistant to Professor B. Brauner in the Institute of Analytical Chemistry of the Charles University, Prague; he was promoted to Associate Professor in 1922 and in 1926 he became the university's first professor of physical chemistry.

Heyrovský's invention of the polarographic method dates from 1922 and he concentrated his whole further scientific activity on the development of this new branch of electrochemistry. He formed a school of Czech polarographers in the university, and was himself in the forefront of polarographic research. In 1950 Heyrovský was appointed as the Director of the newly established Polarographic Institute, which was incorporated into the Czechoslovak Academy of Sciences in 1952.

In 1926 Professor Heyrovský married Marie (Mary) Koranová, and the couple had two children, a daughter, Jitka, and a son, Michael.

Jaroslav Heyrovský died on 27 March 1967. He was interred in the Vyšehrad cemetery in Prague.

Honors, awards, legacy

Many universities and seats of learning honored Heyrovský. He was elected Fellow of University College, London, in 1927, and received honorary doctorates from the Technical University, Dresden in 1955, the University of Warsaw in 1956, the University Aix-Marseille in 1959, and the University of Paris in 1960. He was granted honorary membership in the American Academy of Arts and Sciences in 1933; in the Hungarian Academy of Sciences in 1955; the Indian Academy of Sciences, Bangalore, in 1955; the Polish Academy of Sciences, Warsaw, in 1962; was elected Corresponding Member of the German Academy of Sciences, Berlin, in 1955; member of the German Academy of Natural Scientists, Leopoldina (Halle-Saale) in 1956; Foreign Member of the Royal Danish Academy of Sciences, Copenhagen, in 1962; Vice-President of the International Union of Physics from 1951 to 1957; President and first honorary member of the Polarographic Society, London; honorary member of the Polarographic Society of Japan; honorary member of the Chemical Societies of Czechoslovakia, Austria, Poland, England and India. In 1965, Heyrovský was elected a Foreign Member of the Royal Society (ForMemRS) in 1965.

In Czechoslovakia Heyrovský was awarded the State Prize, First Grade, in 1951, and in 1955 the Order of the Czechoslovak Republic.

Heyrovský lectured on polarography in the United States in 1933, the USSR in 1934, England in 1946, Sweden in 1947, the People's Republic of China in 1958, and in U.A.R. (Egypt) in 1960 and 1961.

The crater Heyrovský on the Moon is named in his honour.

Jai Ganesh · This is Cool

Calyx

Gist

What Is a Calyx? In flowering plants (also called angiosperms), the part of the flower that surrounds the growing bud, often found at the base of the bloom, is called the calyx. The calyx is composed of one or more leaf-like structures called sepals.

Are sepals called calyx?

Collectively, the sepals are called the calyx (plural: calyces), the outermost whorl of parts that form a flower. The word calyx was adopted from the Latin calyx, not to be confused with calix 'cup, goblet'.

Summary

Calyx is the usually green outer whorl of a flower consisting of separate or fused sepals. The calyx serves primarily to protect the developing flower bud and, in some cases, to support the flower once it has bloomed. In some species, the calyx persists even when the fruit matures, as seen in persimmon, eggplant, strawberry, and tomato. Given that it is not directly involved in reproduction, the calyx is considered an accessory part of the flower.

There are commonly four distinct whorls of flower parts: (1) an outer calyx consisting of sepals; (2) the corolla, within the calyx and consisting of petals; (3) the male androecium, comprising the pollen-bearing stamens; and (4) the female gynoecium, at the center and consisting of the pistils, which hold ovules and one or more ovaries. A flower’s calyx and corolla (e.g., all the sepals and petals together) form the perianth, which serves to protect the reproductive organs and attract pollinators. The arrangement of floral organs, including the calyx, is typically in concentric whorls, with the sepals forming the outermost layer, though not every flower has every whorl. The numbers and arrangements of flower parts—including the number and degree of fusion of the sepals of the calyx—are key characteristics botanists use to identify flowering plant species.

The calyx exhibits a wide range of morphological diversity across different angiosperm species. In some flowers, the sepals are free and distinct, a condition known as aposepalous or polysepalous. In other species, the sepals are fused together, forming a tubular structure with lobes or teeth at the end, a condition referred to as synsepalous. The number of sepals in a calyx often corresponds to the number of petals, either directly (e.g., five sepals and five petals) or in multiples (e.g., four sepals and eight petals). In some species, the sepals are brightly colored and function as petals—for example, Clematis and Bougainvillea. In others, the petals and sepals are both present but are similar in color and appearance, as in the tulip tree (Liriodendron tulipifera) and Easter lily (Lilium longiflorum); in such cases, they are known as tepals.

Details

A sepal is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom. Collectively, the sepals are called the calyx.

Description

Sepals are usually green. The term tepal is usually applied when the parts of the perianth are difficult to distinguish, e.g. the petals and sepals share the same color or the petals are absent and the sepals are colorful. When the undifferentiated tepals resemble petals, they are referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly colored tepals. Since they include Liliales, an alternative name is lilioid monocots. Examples of plants in which the term tepal is appropriate include genera such as Aloe and Tulipa. In contrast, genera such as Rosa and Phaseolus have well-distinguished sepals and petals.[citation needed]

The number of sepals in a flower is its merosity. Flower merosity is indicative of a plant's classification. The merosity of a eudicot flower is typically four or five. The merosity of a monocot or palaeodicot flower is three, or a multiple of three.

The development and form of the sepals vary considerably among flowering plants. They may be free (polysepalous) or fused together (gamosepalous). Often, the sepals are much reduced, appearing somewhat awn-like, or as scales, teeth, or ridges. Most often such structures protrude until the fruit is mature and falls off.

Examples of flowers with much-reduced perianths are found among the grasses.

In some flowers, the sepals are fused towards the base, forming a calyx tube (as in the families Lythraceae and Fabaceae). In other families (e.g. Rosaceae and Myrtaceae), a hypanthium includes the bases of sepals, petals, and the attachment points of the stamens.

Mechanical cues may be responsible for sepal growth and there is a strong evidence suggesting that microtubules are present and determine the tensile strength and direction of growth at a molecular level.

Morphology

Morphologically, both sepals and petals are modified leaves. The calyx (the sepals) and the corolla (the petals) are the outer sterile whorls of the flower, which together form the perianth. In some plants, such as Aristolochia, the calyx is the primary whorl, forming a flower up to 50 cm (20 in) wide, with one sepal growing to a slender ribbon with a length of up to 4 m (13 ft) in Aristolochia grandiflora, the largest of all calyces.

Function

Sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom.

Similarly to ordinary leaves, sepals are capable of performing photosynthesis. However, photosynthesis in sepals occurs at a slower rate than in ordinary leaves due to sepals having a lower stomatal density which limits the spaces for gas exchange.

After flowering, most plants have no more use for the calyx, which withers or becomes vestigial, although in a few plants such as Lodoicea and Solanum melongena (aubergine, brinjal) the calyx grows along with the fruit, possibly to protect the attachment point. Some plants retain a thorny calyx, either dried or live, as protection for the fruit or seeds. Examples include species of Acaena, some of the Solanaceae (for example the tomatillo Physalis philadelphica), and the water caltrop, Trapa natans. In some species, the calyx not only persists after flowering but instead of withering, begins to grow until it forms a bladder-like enclosure around the fruit. This is an effective protection against some kinds of birds and insects, for example in Hibiscus trionum and in Physalis species. In some other plants, the calyx grows into an accessory fruit.

Additional Information:

Calyx Meaning

The outermost whorl of the flower is referred to as the calyx. Sepals are the functional units of the calyx, meaning that the calyx is a collection of sepals. The sepals are mostly green in colour and protect the inner structures of the flower from breakage, mechanical injury and desiccation. It supports the other internal structures of flowers such as the corolla, gynoecium and androecium. Corolla is the collection of petals, androecium is the male reproductive whorl and gynoecium is the female reproductive whorl of the flower.

The calyx is found just below the corolla. In some plants, the calyx and corolla are indistinguishable and are termed as perianth. Once the flower has bloomed, the calyx goes on to support the development of fruit. Sometimes, an additional whorl is found externally to the calyx that consists of a whorl of bracts that arise by the union of sepal appendages.

Forms of Calyx

* Polysepalous: When the calyx consists of sepals that are free from each other, it is referred to as polysepalous. E.g., Rose, Cassia
* Gamosepalous: When the sepals are fused in the calyx, it is referred to as gamosepalous. E.g., Datura
* Caducous: When the sepals of a flower wither or drop off, it is referred to as caducous. E.g., Poppy
* Petalloid: In petalloid conditions, the sepals of the flowers are coloured. E.g., Delphinium
* Persistent: In this form, the sepals do not wither and are persistent even in the fruits. E.g., Brinjal.

Functions of Calyx in Plants

The calyx serves several essential functions in the life cycle of a plant. These are:

* Protection: Primarily, the calyx is a protective covering for the developing flower bud, shielding it from physical damage, desiccation, and predation.
* Support: The calyx also provides structural support to the flower, holding its various components in place as it grows and develops. This support is crucial, especially in windy conditions, as it prevents the flower from dislodging or damaging.
* Regulation of Pollination: The sepals of the calyx can also play a role in attracting pollinators to the flower. In some plant species, the sepals' color, shape, and texture may aid in pollinator attraction, ultimately facilitating the transfer of pollen and ensuring successful fertilization, like in Petalloid Calyx.
* Water Regulation: The calyx also helps regulate the uptake and retention of water within the flower bud. The calyx prevents excessive water loss through transpiration and maintains optimal flower hydration.

The different types of calyx are:

* Polysepalous Calyx: This type of Calyx has sepals that are free and separate from each other. Polysepalous calyx examples are found in flowers like Hibiscus and Camellia, where individual sepals encircle the base of the flower, forming a protective shield around the developing bud.
* Gamosepalous Calyx: The sepals in this type are fused or united, forming a single structure. The Petunia is a classic example of a plant having a gamosepalous calyx.
* Caducous Calyx: Caducous Calyx is a calyx where the sepals eventually wither or fall off after the flower blooms. This can be seen in trees like the Maple, where the calyx serves its protective purpose during the bud's development and sheds away once the flower matures.
* Petalloid Calyx: Here, the sepals transform remarkably, adopting colors akin to petals. This phenomenon can be seen in plants like the Poinsettia, where the calyx protects and contributes to the flower's reproductive success by attracting pollinators like bright-colored petals.
* Persistent Calyx: The sepals remain even after the flower has bloomed. Instead of withering away, they stay attached to the developing fruit, offering continued support and protection. A notable example of this can be found in the Tomato plant, where the calyx persists even as the fruit ripens.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#10727. What does the term in Biology Fitness mean?

#10728. What does the term in Biology Fitness landscape mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#5923. What does the adjective musty mean?

#5924. What does the noun mutation mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#2558. What does the medical term Funiculus (neuroanatomy) mean?

Jai Ganesh · Science HQ

Laser Surgery

Gist

Laser surgery uses highly focused, intense light beams to treat, remove, or alter tissue with high precision, often serving as a minimally invasive alternative to traditional surgery. It commonly cuts, vaporizes, or coagulates tissue in various fields, including ophthalmology (LASIK), dermatology (skin lesions), and general surgery. Key benefits include faster recovery, reduced blood loss, and improved precision (LASIK: LASIK stands for Laser-Assisted In Situ Keratomileusis and is a procedure that permanently changes the shape of the cornea, the clear covering of the front of the eye, using an excimer laser.)

What is the laser surgery used for?

To help prevent blood loss by sealing small blood vessels. Refractive eye surgery. Dental procedures. To treat some skin conditions, including to remove warts, moles, tattoos, birthmarks, acne, scars, wrinkles, and unwanted hair.

Summary

Laser surgery is a type of surgery that uses special light beams instead of instruments for surgical procedures. LASER stands for "Light Amplification by the Stimulated Emission of Radiation." Lasers were first developed in 1960.

Newer laser modifications continue to have a large impact on medical and surgical practices. A large part of their impact has been seen in the treatment of various skin lesion and diseases.

What types of surgeries use lasers?

There are many indications for the use of lasers in surgery. The following are some of the more common indications:

* To remove tumors
* To help prevent blood loss by sealing small blood vessels
* To seal lymph vessels to help decrease swelling and decrease the spread of tumor cells
* To treat some skin conditions, including to remove or improve warts, moles, tattoos, birthmarks, scars, and wrinkles

How are lasers used during cancer surgery?

Laser surgery is a type of surgery that uses special light beams instead of instruments, such as scapels, to perform surgical procedures. There are several different types of lasers, each with characteristics that perform specific functions during surgery. Laser light can be delivered either continuously or intermittently and can be used with fiber optics to treat areas of the body that are often difficult to access. The following are some of the different types of laser used for cancer treatment:

* Carbon dioxide (CO2) lasers: Carbon dioxide (CO2) lasers can remove a very thin layer of tissue from the surface of the skin without removing deeper layers. The CO2 laser may be used to remove skin cancers and some precancerous cells.

* Neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers: Neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers can penetrate deeper into tissue and can cause blood to clot quickly. The laser light can be carried through optical fibers to reach less accessible internal parts of the body. For example, the Nd:YAG laser can be used to treat throat cancer.

* Laser-induced interstitial thermotherapy (LITT): Laser-induced interstitial thermotherapy (LITT) uses lasers to heat certain areas of the body. The lasers are directed to areas between organs (interstitial areas) that are near a tumor. The heat from the laser increases the temperature of the tumor, thereby shrinking, damaging, or destroying the cancer cells.

* Argon lasers: Argon lasers pass only through superficial layers of tissue such as skin. Photodynamic therapy (PDT) uses argon laser light to activate chemicals in the cancer cells.

Details

Laser surgery is a type of surgery that cuts tissue using a laser in contrast to using a scalpel.

Soft-tissue laser surgery is used in a variety of applications in humans (general surgery, neurosurgery, ENT, dentistry, orthodontics, and oral and maxillofacial surgery) as well as veterinary surgical fields. The primary uses of lasers in soft tissue surgery are to cut, ablate, vaporize, and coagulate. There are several different laser wavelengths used in soft tissue surgery. Different laser wavelengths and device settings (such as pulse duration and power) produce different effects on the tissue. Some commonly used lasers types in soft tissue surgery include erbium, diode, and CO2. Erbium lasers are excellent cutters, but provide minimal hemostasis. Diode lasers (hot tip) provide excellent hemostasis, but are slow cutters. CO2 lasers are both efficient at cutting and coagulating. Laser surgery is commonly used on the eye. Techniques used include LASIK, which is used to correct near and far-sightedness in vision, and photorefractive keratectomy, a procedure which permanently reshapes the cornea using an excimer laser to remove a small amount of the human tissue.

Effects

* Photochemical effect: clinically referred to as photodynamic therapy. Photosensitizer (photophrin II) is administered which is taken up by the tumor tissue and later irradiated by laser light resulting in highly toxic substances with resultant necrosis of the tumor. Photodynamic therapy is used in palliation of oesophageal and bronchial carcinoma and ablation of mucosal cancers of Gastrointestinal tract and urinary bladder.
* Photoablative effect: Used in eye surgeries like refractive surgery, band keratoplasty, and endartectomy of peripheral blood vessels.
* Photothermal effect: this property is used for endoscopic control of bleeding e.g. Bleeding peptic ulcers, oesophageal varices
* Photomechanical effect: used in intraluminal lithotripsy

Equipment

Surgical laser systems, sometimes called "laser scalpels", are differentiated not only by the wavelength, but also by the light delivery system: flexible fiber or articulated arm, as well as by other factors. Types of surgical lasers include carbon dioxide, argon, Nd:YAG laser, and potassium titanyl phosphate. CO2 lasers were the dominant soft-tissue surgical lasers as of 2010. (Nd:YAG (neodymium-doped yttrium aluminium garnet; Nd:Y3Al5O12) is a crystal that is used as a lasing medium for solid-state lasers.)

Applications:

Dermatology and plastic surgery

A range of lasers such as erbium, dye, Q switch lasers, and CO2 are used to treat various skin conditions including scars, vascular and pigmented lesions, and for photorejuvenation. The laser surgery for dermatology often bypasses the skin surface. The principle of laser surgery for dermatologic problems is based on SPTL (selective photothermolysis). The laser beam penetrates the skin until it encounters chromophore which absorbs the laser beam. After absorption of the laser beam, heat is generated to induce coagulation, necrosis of the targeted tissue, this results in the removal of unwanted tissue by laser surgery.

Laser resurfacing is a technique in which covalent bonds of a material are dissolved by a laser, a technique invented by aesthetic plastic surgeon Thomas L. Roberts, III using CO2 lasers in the 1990s.

Lasers are also used for laser-assisted lipectomy.

Eye surgery

Various types of laser surgery are used to treat refractive error. LASIK, in which a knife is used to cut a flap in the cornea, and a laser is used to reshape the layers underneath, is used to treat refractive error. IntraLASIK is a variant in which the flap is also cut with a laser. In photorefractive keratectomy (PRK, LASEK), the cornea is reshaped without first cutting a flap. In laser thermal keratoplasty, a ring of concentric burns is made in the cornea, which causes its surface to steepen, allowing better near vision. ReLEx SMILE is the latest advancement in laser vision correction technology. In SMILE surgery, ZEISS VisuMax femtosecond laser is used to make a small incision and to create a pre-calculated mini lens tissue (or lenticule) inside the cornea.

Lasers are also used to treat non-refractive conditions, such as phototherapeutic keratectomy (PTK) in which opacities and surface irregularities are removed from the cornea and laser coagulation in which a laser is used to cauterize blood vessels in the eye, to treat various conditions. Lasers can be used to repair tears in the retina.

Endovascular surgery

Laser endarterectomy is a technique in which an entire atheromatous plaque in the artery is excised. Other applications include laser assisted angioplasties and laser-assisted vascular anastomosis.

Foot and ankle surgery

Lasers are used to treat several disorders in foot and ankle surgery. They are used to remove benign and malignant tumors, treat bunions, debride ulcers and burns, excise epidermal nevi, blue rubber bleb nevi, and keloids, and the removal of hypertrophic scars and tattoos.

A carbon dioxide laser (CO2) is used in surgery to treat onychocryptosis (ingrown nails), onychauxis (club nails), onychogryposis (rams horn nail), and onychomycosis (fungus nail).

Gastro-intestinal tract

1) Peptic ulcer disease and oesophageal varices - Laser photoablation is done.
2) Coagulation of vascular malformations of stomach, duodenum, and colon.
3) Lasers can be effectively used to treat early gastric cancers provided they are less than 4 cm and without lymph node involvement. Lasers are also used in treating oral submucous fibrosis.
4) Palliative laser therapy is given in advanced oesophageal cancers with obstruction of lumen. Recanalisation of the lumen is done which allows the patient to resume a soft diet and maintain hydration.
5) Ablative laser therapy is used in advanced colorectal cancers to relieve obstruction and to control bleeding.
6) Laser surgery used in hemorrhoidectomy, and is a relatively popular and non-invasive method of hemorrhoid removal.
7) Laser-assisted liver resections have been done using carbon dioxide and Nd:YAG lasers.
8) The ablation of liver tumors can be achieved by selective photovaporization of the tumor.
9) Endoscopic laser lithotripsy is a safer modality compared to electrohydraulic lithotripsy.

Oral and dental surgery

The CO2 laser is used in oral and dental surgery for virtually all soft-tissue procedures, such as gingivectomies, vestibuloplasties, frenectomies, and operculectomies. The CO2 10,600 nm wavelength is safe around implants as it is reflected by titanium, and thus has been gaining popularity in the field of periodontology. The laser may also be effective in treating peri-implantitis.

Spine surgery

Laser spine surgery first began seeing clinical use in the 1980s and was primarily used within discectomy to treat lumbar disc disease under the notion that heating a bulging disc vaporized enough tissue to relieve pressure on the nerves and help alleviate pain.

Since that time, laser spine surgery has become one of the most marketed forms of minimally invasive spine surgery, despite the fact that it has never been studied in a controlled clinical trial to determine its effectiveness apart from disc decompression. Evidence-based data surrounding the use of lasers in spine surgery is limited and its safety and efficacy were poorly understood as of 2017.

Thoracic surgery

In thoracic surgery, surgical laser applications are most often used to remove pulmonary metastases and tumors of different primary localizations. Other areas of application are surgical sectioning of the parenchyma, anatomic segmental resections, removal of tumors from the thoracic wall and abrasion of the pleura parietalis. Since the introduction of surgical lasers, the amount of potentially surgically resectable pulmonary nodules has significantly increased. Compared to laser surgery, other conventional surgical methods such as segmental or wedge resections with surgical stapling will normally lead to a bigger loss of lung tissue, especially in patients with multiple pulmonary nodules methods.

Other advantages of laser surgery compared to conventional methods are that it leads to an improved postoperative lung function and that it gives the additional possibility to histologically analyze the removed material which would otherwise be destroyed through radiation or heat.

Hard tissues

Lasers are used to cut or ablate bones and teeth in dentistry.

Other surgery

The CO2 laser is also used in gynecology, genitourinary, general surgery, otorhinolaryngology, orthopedic, and neurosurgery.

Additional Information:

What is laser surgery?

Laser surgery is a type of surgery that uses special light beams instead of instruments for surgical procedures.

How does a laser work?

The functioning of a laser goes back to Albert Einstein's theory of stimulated emission of radiation. It also includes other theories that help explain local tissue damage. As the light beam hits the skin, the skin may either reflect the light away, scatter the light, absorb the light, or let the light pass right through the different layers of the skin.

Certain parts of the skin called chromophores absorb the light. When these chromophores absorb the light, physical, mechanical, chemical, or temperature changes may occur in the tissue.

There are many different types of lasers. They include the carbon dioxide laser, the YAG (neodymium, or yttrium aluminum garnet) laser, and the argon laser. Each one works differently and may be used for different treatment options. Laser light can be delivered either continuously or intermittently. The wavelength of the laser determines the target within the skin and the effect it may have.

What types of surgeries use lasers?

There are many reasons to use lasers in surgery. The following are some of the more common reasons:

* To shrink or destroy tumors
* To help prevent blood loss by sealing small blood vessels
* Refractive eye surgery
* Dental procedures
* To treat some skin conditions, including to remove warts, moles, tattoos, birthmarks, acne, scars, wrinkles, and unwanted hair.

image?url=https%3A%2F%2Fbed.apexhospitals.com%2Fuploads%2Flaser_surgery_8f769b34a8.png&w=1200&q=75

Jai Ganesh · Dark Discussions at Cafe Infinity

Combination Quotes - II

1. Art imitates life and, sometimes, life imitates art. It's a weird combination of elements. - Bruce Willis

2. There is a certain combination of anarchy and discipline in the way I work. - Robert De Niro

3. I am a combination of being an introvert and an extrovert - I am cordial, I connect, I can chat with people and then I like to be in my own space. - Bhumika Chawla

4. Music is so abstract; it is a combination of words and melody. - Shankar Mahadevan

5. Ideas rose in clouds; I felt them collide until pairs interlocked, so to speak, making a stable combination. - Henri Poincare

6. I think the combination of graduate education in a field like Computer Science and the opportunity to apply this in a work environment like Microsoft is what drove me. The impact these opportunities create can lead to work that has broad, worldwide impact. - Satya Nadella

7. We talk about this concept of openness and transparency as the high-level ideal that we're moving towards at Facebook. The way that we get there is by empowering people to share and connect. The combination of those two things leads the world to become more open. - Mark Zuckerberg

8. It's always a combination of physics and poetry that I find inspiring. It's hard to wrap your head around things like the Hubble scope. - Tom Hanks.

Jai Ganesh · Jokes

Q: Why are men are like coffee?
A: The best ones are rich, hot, and can keep you up all night!
* * *
Q: What do you call a cow who's just given birth?
A: De-calf-inated!
* * *
Q: Why are all Jewish men required to make a good cup of coffee?
A: Because according to the Torah He Brews!
* * *
Q: Why is a bad cup of coffee the end of a marriage?
A: Because it's GROUNDS for divorce!
* * *
Q: What is best Beatles song?
A: Latte Be!
* * *

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#9843.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#6337..

Jai Ganesh · Exercises

Hi,

2694.

Jai Ganesh · This is Cool

Corolla

Gist

A corolla is the collection of a flower's petals, often brightly colored to attract pollinators, forming the second whorl inside the sepals and surrounding the reproductive organs (stamens and pistils) to help with pollination and protect them. It comes from the Latin word for "wreath" or "crown" and can vary greatly in shape (bell, funnel, tubular) and fusion (fused or free) across different plants.

The corolla is the name given to the collective rings of petals around a flower and its reproductive organs. The corolla functions in aiding the reproduction process known as pollination. Pollination is when pollen is transferred between flowers resulting in fertilization.

Summary

Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the corolla. Petals are usually surrounded by an outer whorl of modified leaves called sepals, that collectively form the calyx and lie just beneath the corolla. The calyx and the corolla together make up the perianth, the non-reproductive portion of a flower. When the petals and sepals of a flower are difficult to distinguish, they are collectively called tepals. Examples of plants in which the term tepal is appropriate include genera such as Aloe and Tulipa. Conversely, genera such as Rosa and Phaseolus have well-distinguished sepals and petals. When the undifferentiated tepals resemble petals, they are referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly coloured tepals. Since they include Liliales, an alternative name is lilioid monocots.

Although petals are usually the most conspicuous parts of animal-pollinated flowers, wind-pollinated species, such as the grasses, either have very small petals or lack them entirely (apetalous).

Corolla

The collection of all petals in a flower is referred to as the corolla. The role of the corolla in plant evolution has been studied extensively since Charles Darwin postulated a theory of the origin of elongated corollae and corolla tubes.

A corolla of separate petals, without fusion of individual segments, is apopetalous. If the petals are free from one another in the corolla, the plant is polypetalous or choripetalous; while if the petals are at least partially fused, it is gamopetalous or sympetalous. In the case of fused tepals, the term is syntepalous. Fused petals may form a tube, which is then known as a 'corolla tube'.

Details

A petal, in flowering plants, is a sterile floral part that usually functions as a visually conspicuous element of a flower. Petals are modified leaves and are often brightly colored or white to attract specific pollinators to the flower. Petals often come in multiples of three in monocots or in multiples of four or five in eudicots. Many horticultural flowers, such as roses and peonies, have been bred to have multiple layers of petals, resulting in showy, textured blooms.

Many flowers have two sets of sterile appendages, the petals and the sepals, that are attached below the fertile parts of the flower, the stamens and the pistils. All of the petals of a flower are collectively called the corolla, while all the sepals form the calyx. The calyx and the corolla together are referred to as the perianth. Like petals, sepals are modified leaves, but they are often green and somewhat rugged; they serve to protect and enclose the flower bud. Petals, by contrast, are often thinner and more delicate than sepals and come in a myriad of colors. In some flowers, such as many lilies and orchids, the petals and sepals are nearly indistinguishable in appearance; such undifferentiated structures are known as tepals.

The “petals” of certain members of the aster family (Asteraceae), such as those of daisies and sunflowers, are actually each individual flowers on a composite head. In more than half the members of the family, these ray flowers form in the outermost row or rows of the composite head and have a modified, mainly flat and elongate corolla that resembles an individual petal of most other flowers.

Additional Information:

Parts of a Flower

Plants are primarily divided into flowering and non-flowering classes based on whether they have flowers. A flower, a defining feature of flowering plants, is essentially an extension of the shoot used for reproduction.

The four primary components of most flowers are sepals, petals, stamens, and carpels. The female component of the flower is the carpels, while the male component is the stamens. Most flowers are hermaphrodites, meaning they have both male and female components. Others may be male or female and contain one of the two parts.

* Peduncle: The flower’s stalk is known as a peduncle.
* Receptacle: This is the area of the flower where the stalk is attached. It is tiny and is located at the centre of the flower’s base.
* Petals: This layer is located right above the sepal layer. The collection of petals is known as the corolla. Since their primary function is to draw pollinators, such as insects, butterflies, and other creatures, to the flower, they are often brightly coloured.
* Sepals: At the base of the petals, they are tiny, leaf-like components. They constitute the top whorl of the flower. Sepals are collectively referred to as the calyx. The primary purpose of the calyx and its sepals is to safeguard the flower before blooming (in the bud phase).
* Stamens: They are the male components of a flower. The androecium is a collection of many stamens. They are structurally separated into two parts:
* Filament: The extended, slender portion that connects the anther to the flower is called a filament.
* Anthers: The stamen’s head is where the pollen is produced, which is then transmitted to the pistil or other female sections of the same or different flower to induce fertilisation.
* Pistil: This constitutes the female components of a flower. The pistil consists of four parts: Style, Stigma, Ovary, and Ovules. The gynoecium is the term for a collection of pistils.

Corolla of Flower

What do you see when you first look at a flowering plant? Is it the flower, the stem, or the leaves? The brightly coloured petals of the flower are the most prominent part of most flowering plants. The corolla is the collective term for the arrangement of petals of flowers, which are frequently placed in a circle around the flower’s centre.

Most flowers include sepals, or little leaf-like structures, on the outside of the corolla that surround the petals before the flower develops. Most flowers have three more circles of structures added to the corolla that make up the entire flower. The first circle of structures inside the corolla is made up of many stamens and other male reproductive elements. The female reproductive part, known as the pistil, is located in a circle at the centre of the flower.

In this article, we will learn the corolla’s meaning, features, variations, and significant functions.

Meaning of Corolla

In plants, the term “corolla” refers to a collection of petals that strongly displays colour and encircles the stamen and carpel, the reproductive organs of a flower. Therefore, corolla or petals refers to the second whorl of a flower, which is internal to the calyx. Corollas can also be gamopetalous (fused) and polypetalous (free), just like the calyx.

Plants have a wide range of corolla shapes and colours. Corolla might be wheel-shaped, bell-shaped, tubular, or styled like a funnel. These corollas draw insects to the flower, and while at the flower, these insects participate in pollination.

Features of Corolla of Flower

* The important function of petals is to keep the vital flower components in their younger state.
* Due to the presence of specific pigments such as water-soluble anthocyanin, anthoxanthin, carotenoids, etc., corolla typically has a vibrant colour.
* The essential oil gives the petals their fragrance.
* Additionally, the petals have organs called nectaries that produce sugar-rich nectar to attract insects.
* Sepaloid has petals that are pale or green in colour. Examples are the Polyalthia and Annona species.
* The petals can occasionally be thicker while often being thin.
* The petal structure consists of two parts: the claw and the limb.
* The claw is the thin, stalk-like basal portion of a petal. All clawless bracts are sessile.
* A limb is the enlarged apex of the petals.
* Petals can have regular or irregular sizes and shapes.
* The corolla can have bilateral or radial symmetry.
* The edges of a petal might be whole, serrated, split, etc., much like a leaf lamina.

Functions of Corolla

Corolla performs three functional activities:

1. Pollination: The flower petals have a vibrant appearance and an aromatic fragrance that attracts everyone’s attention. Bees, birds, and other pollinating creatures thus aid in the fertilisation of flowers.

2. Storage: To draw pollinators, petals serve as storage for sugar-rich nectar.

3. Protection: The male (stamen) and female (carpel) reproductive elements of the flower, which are involved in fertilising the flower to generate fruits, are protected by the whorl of petals.

Conclusion

Thus, the group of petals collectively known as corolla is the most appealing feature of a flower due to its vibrant colours and fragrance. Although it does not directly participate in pollination, it indirectly can attract or deter specific pollinators.

Jai Ganesh · This is Cool

2484) Maldives

Gist

The official language of the Maldives is Dhivehi (Maldivian), an Indo-Aryan language, but English is widely spoken, especially in tourist areas and resorts, making communication easy for visitors, while Arabic serves as the religious language for Islam.

Summary

Maldives, officially the Republic of Maldives, and historically known as the Maldive Islands, is an archipelagic country in South Asia, located in the eastern Arabian Sea, within the northern Indian Ocean. Maldives is southwest of Sri Lanka and India, about 750 kilometres (470 miles; 400 nautical miles) from the Asian continent's mainland. Maldives' chain of 26 atolls stretches across the equator from Ihavandhippolhu Atoll in the north to Addu Atoll in the south.

Maldives is the smallest country in Asia. Its land area is only 298 square kilometres (115 sq mi), but this is spread over roughly 90,000 square kilometres (35,000 sq mi) of the sea, making it one of the world's most spatially dispersed sovereign states. With a population of 515,132 in the 2022 census, it is the second least populous country in Asia and the ninth-smallest country by area, but also one of the most densely populated countries. Maldives has an average ground-level elevation of around 1.5 metres (4 ft 11 in) above sea level, and a highest natural point of only 2.4 metres (7 ft 10 in), making it the world's lowest-lying country. Some sources state the highest point, Mount Villingili, as 5.1 metres or 17 feet.

Malé is the capital and the most populated city, traditionally called the "King's Island", where the ancient royal dynasties ruled from its central location. Maldives has been inhabited for over 2,500 years. Documented contact with the outside world began around 947 AD when Arab travellers began visiting the islands. In the 12th century, partly due to the importance of the Arabs and Persians as traders in the Indian Ocean, Islam reached the Maldivian Archipelago. Maldives was soon consolidated as a sultanate, developing strong commercial and cultural ties with Asia and Africa. From the mid-16th century, the region came under the increasing influence of European colonial powers, with Maldives becoming a British protectorate in 1887. Independence from the United Kingdom came in 1965, and a presidential republic was established in 1968 with an elected People's Majlis. The ensuing decades have seen political instability, efforts at democratic reform, and environmental challenges posed by climate change and rising sea levels. Maldives became a founding member of the South Asian Association for Regional Cooperation (SAARC).

Fishing has historically been the dominant economic activity, and remains the second largest sector, behind the rapidly growing tourism industry. Maldives rates "high" on the Human Development Index, with a per capita income significantly higher than other SAARC nations. The World Bank classifies Maldives as having an upper-middle income economy.

Maldives is a member of the United Nations, the Commonwealth of Nations, the Organisation of Islamic Cooperation, and the Non-Aligned Movement, and is a Dialogue Partner of the Shanghai Cooperation Organisation. It temporarily withdrew from the Commonwealth in October 2016 after being threatened with expulsion from the organisation for its human rights infringements and democratic backsliding. It was readmitted to the Commonwealth on 1 February 2020 after showing evidence of reform and functioning democratic processes.

Details

Maldives is an independent island country in the north-central Indian Ocean. It consists of a chain of about 1,200 small coral islands and sandbanks (some 200 of which are inhabited), grouped in clusters, or atolls.

The islands extend more than 510 miles (820 km) from north to south and 80 miles (130 km) from east to west. The northernmost atoll is about 370 miles (600 km) south-southwest of the Indian mainland, and the central area, including the capital island of Male (Male’), is about 400 miles (645 km) southwest of Sri Lanka.

Land

The Maldive Islands are a series of coral atolls built up from the crowns of a submerged ancient volcanic mountain range. All the islands are low-lying, none rising to more than 6 feet (1.8 metres) above sea level. Barrier reefs protect the islands from the destructive effects of monsoons. The rainy season, from May to August, is brought by the southwest monsoon; from December to March the northeast monsoon brings dry and mild winds. The average annual temperature varies from 76 to 86 °F (24 to 30 °C). Rainfall averages about 84 inches (2,130 mm) per year. The atolls have sandy beaches, lagoons, and a luxuriant growth of coconut palms, together with breadfruit trees and tropical bushes. Fish abound in the reefs, lagoons, and seas adjoining the islands; sea turtles are caught for food and for their oil, a traditional medicine.

People

The population of Maldives belongs almost entirely to the Maldivian ethnic group, which is the result of various peoples settling in the islands successively through the country’s history. The first settlers, it is generally believed, were Tamil and Sinhalese peoples from southern India and Sri Lanka. Traders from Arab countries, Malaya, Madagascar, Indonesia, and China visited the islands through the centuries. The official language is an Indo-European language called Dhivehi (or Maldivian); Arabic, Hindi, and English are also spoken. Islam is the state religion.

More than half of the population is considered rural. With the exception of those living in Male, the only relatively large settlement in the country, the inhabitants of the Maldives live in villages on small islands in scattered atolls. Only about 20 of the islands have more than 1,000 inhabitants, and the southern islands are more densely populated than the northern ones. The birth rate for the Maldives is somewhat higher than the world average, but the death rate is lower. More than one-fifth of the total population is under 15 years of age. Life expectancy is about 74 years for men and 79 for women.

Economy

Since the 1970s the economy of the Maldives has developed rapidly. Annual growth of gross domestic product (GDP) has been high, averaging about 6 percent in the 2010s, and the gross national income (GNI) per capita—among the lowest in the world in the 1970s—reached the level of upper middle-income countries by the late 2010s. The economy is based on tourism, fishing, boatbuilding, and boat repairing, with the tourism sector driving the rapid growth.

Agriculture, forestry, and fishing

Fishing, long the traditional base of the economy, has been far surpassed by tourism as the main source of gross domestic product (GDP). While the sector still produces the bulk of the country’s exports and continues to grow (albeit at a slower pace than the tourism industry), it employs less than one-fifth of the labour force and contributes less than one-tenth of the GDP. Tuna is the predominant fish caught, traditionally by the pole-and-line method, although a good deal of the fishing fleet has been mechanized. Most of the fish catch is sold to foreign companies for processing and export.

Although formal businesses have seen rapid growth in the country, especially on the main islands, much of the population subsists outside the money economy on fishing, coconut collecting, and the growing of vegetables and melons, roots and tubers (cassava, sweet potatoes, and yams), and tropical fruits. Cropland, scattered over many small islands, is minimal, and nearly all the staple foods must be imported.

Manufacturing

Industries are largely of the handicraft or cottage type, including the making of coir (coconut-husk fibre) and coir products, fish canning, and boatbuilding. Textile and garment manufacturing was among the more lucrative industries from the mid-1990s until the 2005 expiry of an import quota regime in international textile trade left factories in the Maldives unable to compete. Construction makes up the bulk of the industrial sector.

Trade

Maldives entered the South Asian Free Trade Area (SAFTA) in 2006 and signed a free trade agreement with China in 2017. Imports include consumer goods such as food (principally rice), textiles, medicines, and petroleum products. Fish—mostly dried, frozen, or canned skipjack tuna—accounts for the bulk of exports. China, India, the United Arab Emirates, Thailand, Sri Lanka, and Singapore are among the main trading partners.

Services

The tourism industry, although nonexistent before 1972, underpins the services sector. Annually, more than 1.5 million tourists visit the Maldives. Its more than 130 resort islands include high-end hotel brands, and its marine geography offers unique diving and water sports opportunities as well as undersea accommodations, restaurants, and spas. By the mid-2010s the service sector accounted for four-fifths of the country’s GDP.

Labour and taxation

The rapid growth of the tourism industry left its mark on the labour market, which saw a dramatic shift away from agriculture and toward services. In part because of lack of training among the general population, a number of foreign workers from South Asia provide skills needed to help develop businesses. As businesses on resort islands away from the general populace demanded an increasing share of the total labour force, the participation rate of women, who are discouraged by the culture from living away from their families, fell substantially. About three-fifths of women participated in the labour force in the 1970s, but the rate dipped as low as one-fifth of women in the mid-1990s. By the 2010s, however, the participation rate had recovered to about half of women.

Beginning in 2011, the Maldives collected taxes primarily on the profits of businesses and financial institutions and on goods and services within the tourism sector. An income tax was implemented in 2020.

Transportation

Transportation between islands and atolls is vital for the country. China and India, competing for influence over the strategically located Maldive Islands, have provided significant foreign direct investment to develop infrastructure that would further connect the islands. Boats provide the principal means of transport between the atolls, and scheduled shipping services link the country with Sri Lanka, Singapore, and India. The national airline carries passengers between several airports in the country as well as internationally. The airport at Male handles most international traffic, although there are other airports that serve limited international travel.

Additional Information

Capital: Male

Area: 300 sq km

Population: 392,000

Languages: Dhivehi, English

The Maldives is a republic lies south-west of the Indian sub-continent. It is made up of a chain of nearly 1,200 islands, most of them uninhabited.

None of the coral islands stand more than 1.8 metres (six feet) above sea level, making the country vulnerable to any rise in sea levels associated with global warming.

The economy revolves around tourism, and scores of islands have been developed for the top end of the tourist market.

Its political history has been unsettled since the electoral defeat of long-serving President Maumoon Abdul Gayoom in 2008.

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Jai Ganesh · Dark Discussions at Cafe Infinity

2422) Owen Chamberlain

Gist:

Work

The matter around us has a kind of mirror image—antimatter. A particle and its antiparticle have an opposite electrical charge, among other things. The electron’s antiparticle positron was the first to be discovered. With high concentrations of energy, a pair of particles and antiparticles can be created, but when a particle and an antiparticle meet, both are annihilated and their mass is converted into radiation. In a 1955 experiment with a powerful particle accelerator, Owen Chamberlain and Emilio Segrè confirmed the existence of the proton’s antiparticle, the antiproton.

Summary

Owen Chamberlain (born July 10, 1920, San Francisco, California, U.S.—died February 28, 2006, Berkeley, California) was an American physicist, who shared the Nobel Prize for Physics in 1959 with Emilio Segrè for their discovery of the antiproton. This previously postulated subatomic particle was the second antiparticle to be discovered and led directly to the discovery of many additional antiparticles.

Chamberlain attended Dartmouth College (B.A., 1941) and the University of California at Berkeley before working on the Manhattan Project, a U.S. research project that produced the first atom bombs. Later, while completing a Ph.D. (1948) at the University of Chicago, he worked at Argonne National Laboratory in Illinois. In 1948 he joined the faculty of the University of California at Berkeley, where he became a full professor in 1958 and professor emeritus in 1989. There he conducted research on alpha particle decay, neutron diffraction in liquids, and high-energy nuclear particle reactions. He and Segrè used the bevatron (a powerful particle accelerator) to produce antiprotons in 1955, and the following year they confirmed the existence of the antineutron.

Details

Owen Chamberlain (July 10, 1920 – February 28, 2006) was an American physicist who shared with Emilio Segrè the Nobel Prize in Physics for the discovery of the antiproton, a sub-atomic antiparticle.

Biography

Born in San Francisco, California, Chamberlain graduated from Germantown Friends School in Philadelphia in 1937. He studied physics at Dartmouth College, where he was a member of Alpha Theta chapter of Theta Chi fraternity, and at the University of California, Berkeley. He remained in school until the start of World War II, and joined the Manhattan Project in 1942, where he worked with Segrè, both at Berkeley and in Los Alamos, New Mexico. He married Beatrice Babette Copper (d. 1988) in 1943, with whom he had four children.

In 1946, after the war, Chamberlain continued with his doctoral studies at the University of Chicago under physicist Enrico Fermi. Fermi acted as an important guide and mentor for Chamberlain, encouraging him to leave behind theoretical physics for experimental physics, for which Chamberlain had a particular aptitude. Chamberlain received his PhD from the University of Chicago in 1949.

In 1948, having completed his experimental work, Chamberlain returned to Berkeley as a member of its faculty. There he, Segrè, and other physicists investigated proton-proton scattering. In 1955, a series of proton scattering experiments at Berkeley's Bevatron led to the discovery of the anti-proton, a particle like a proton but negatively charged. Chamberlain's later research work included the time projection chamber (TPC), and work at the Stanford Linear Accelerator Center (SLAC).

Chamberlain was politically active on issues of peace and social justice, and outspoken against the Vietnam War. He was a member of Scientists for Sakharov, Orlov, and Shcharansky, three physicists of the former Soviet Union imprisoned for their political beliefs. In the 1980s, he helped found the nuclear freeze movement. In 2003 he was one of 22 Nobel Laureates who signed the Humanist Manifesto.

After the death of his first wife in 1988, Chamberlain married artist June Steingart Greenfield, who died in 1991. His third wife, Senta Pugh-Chamberlain (née Gaiser) was the widow of physicist Howell Pugh.

Chamberlain was diagnosed with Parkinson's disease in 1985, and retired from teaching in 1989. He died of complications from the disease on February 28, 2006, in Berkeley at the age of 85. He was survived by his third wife, his four children from his first marriage, and two step-daughters from his third marriage.

Chamberlain plays a central role in Jacob M. Appel's Sherwood Anderson Award-winning short story, "Measures of Sorrow".

Jai Ganesh · Science HQ

Stirrup/Stapes

Gist

What is stirrup in the human body?

The stapes is the body's smallest bone! Sometimes called the stirrup, this delicate bone works with two others in the ear to send sound vibrations into the inner ear.

In medicine, "stirrup" most commonly refers to the stapes, the smallest bone in the human body, located in the middle ear, named for its resemblance to a horse's stirrup and vital for transmitting sound vibrations.

The stapes is one of three bones of the middle ear along with the malleus and incus. These three bones are collectively called auditory ossicles. They are primarily responsible for sound conduction from the tympanic membrane to the middle ear. The stapes is the smallest and the lightest bone of the human body.

Summary

The stapes is one of three bones of the middle ear along with the malleus and incus. These three bones are collectively called auditory ossicles. They are primarily responsible for sound conduction from the tympanic membrane to the middle ear.

The stapes is the smallest and the lightest bone of the human body. It is stirrup-shaped and composed of several parts including the head, neck, anterior limb, posterior limb and base.

The base of the stapes rests on the vestibular window of the inner ear, while its head articulates with the incus through the incudostapedial joint. The incudostapedial joint is a ball and socket type of synovial joint. The neck of the stapes serves as the attachment point for the stapedius muscle.

Details

The stapes or stirrup is a bone in the middle ear of humans and other tetrapods which is involved in the conduction of sound vibrations to the inner ear. This bone is connected to the oval window by its annular ligament, which allows the footplate (or base) to transmit sound energy through the oval window into the inner ear. The stapes is the smallest and lightest bone in the human body, and is so-called because of its resemblance to a stirrup (Latin: Stapes).

Structure

The stapes is the third bone of the three ossicles in the middle ear and the smallest in the human body. It measures roughly 2 to 3 mm, greater along the head-base span. It rests on the oval window, to which it is connected by an annular ligament and articulates with the incus, or anvil through the incudostapedial joint. They are connected by anterior and posterior limbs (Latin: crura).

Development

The stapes develops from the second pharyngeal arch during the sixth to eighth week of embryological development in humans. The central cavity of the stapes, the obturator foramen, is due to the presence embryologically of the stapedial artery, which usually regresses in humans during normal development.

Animals

The stapes is one of three ossicles in mammals. In non-mammalian tetrapods, the bone homologous to the stapes is usually called the columella; however, in reptiles, either term may be used. In fish, the homologous bone is called the hyomandibular, and is part of the gill arch supporting either the spiracle or the jaw, depending on the species. The equivalent term in amphibians is the pars media plectra.

Variation

The stapes appears to be relatively constant in size in different ethnic groups. In 0.01–0.02% of people, the stapedial artery does not regress, and persists in the central foramen. In this case, a pulsatile sound may be heard in the affected ear, or there may be no symptoms at all. Rarely, the stapes may be completely absent.

Function

Situated between the incus and the inner ear, the stapes transmits sound vibrations from the incus to the oval window, a membrane-covered opening to the inner ear. The stapes is also stabilized by the stapedius muscle, which is innervated by the facial nerve.

Clinical relevance

Otosclerosis is a congenital or spontaneous-onset disease characterized by abnormal bone remodeling in the inner ear. Often this causes the stapes to adhere to the oval window, which impedes its ability to conduct sound, and is a cause of conductive hearing loss. Clinical otosclerosis is found in about 1% of people, although it is more common in forms that do not cause noticeable hearing loss. Otosclerosis is more likely in young age groups, and females. Two common treatments are stapedectomy, the surgical removal of the stapes and replacement with an artificial prosthesis, and stapedotomy, the creation of a small hole in the base of the stapes followed by the insertion of an artificial prosthesis into that hole. Surgery may be complicated by a persistent stapedial artery, fibrosis-related damage to the base of the bone, or obliterative otosclerosis, resulting in obliteration of the base.

Additional Information

Stapes bone is the smallest bone in our body. It is the innermost bone of our auditory ossicles in the middle ear, which are responsible for transmitting sound waves from the air outside to the fluid-filled labyrinth (cochlea). Auditory ossicles are a group of three small bones that work together forming a vibrating chain. These three bones are as
follows:

* Malleus
* Incus
* Stapes

For better understanding of the anatomy of Stapes, have a look at the image below:

Related Conditions

* Otosclerosis- A disorder in which the footplate of the stapes is invaded and replaced by an abnormal bone, affecting sound transmission to the inner ear at the level of the oval window.
* Stapedectomy.

Pathological Conditions

Stapes fractures- Transverse fracture of stapes Anterior Crus, a rare fracture.

Jai Ganesh · Dark Discussions at Cafe Infinity

Combination Quotes - I

1. A good head and a good heart are always a formidable combination. - Nelson Mandela

2. There are three principal means of acquiring knowledge... observation of nature, reflection, and experimentation. Observation collects facts; reflection combines them; experimentation verifies the result of that combination. - Denis Diderot

3. Software is a great combination between artistry and engineering. - Bill Gates

4. I believe myself to possess a most singular combination of qualities exactly fitted to make me pre-eminently a discoverer of the hidden realities of nature. - Ada Lovelace

5. God gave women intuition and femininity. Used properly, the combination easily jumbles the brain of any man I've ever met. - Farrah Fawcett

6. Mathematical reasoning may be regarded rather schematically as the exercise of a combination of two facilities, which we may call intuition and ingenuity. - Alan Turing

7. Tennis is a perfect combination of violent action taking place in an atmosphere of total tranquility. - Billie Jean King

8. The future of food security will depend on a combination of the ecological prudence of the past and the technological advances of today. - M. S. Swaminathan.

Jai Ganesh · Jokes

Q: Why did the coconut stop in the middle of the road?
A: Because he ran out of juice!
* * *
Q: What do you call a coconut that doesn't have milk?
A: A milk dud.
* * *
Q: Why don't coconuts have money?
A: Because people milk them dry.
* * *
Q: What is a coconut never guilty of?
A: Nuttiness.
* * *
Q: Why didn't the coconuts go to the ballet?
A: They were afraid of the nutcracker.
* * *

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#10725. What does the term in Geography Volcanic crater lake mean?

#10726. What does the term in Geography Craton mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#5921. What does the adjective frigid mean?

#5922. What does the noun frill mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#2557. What does the medical term Non-Hodgkin lymphoma (NHL) mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#9842.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#6336.

Jai Ganesh · Exercises

Hi,

2693.

Jai Ganesh · This is Cool

Time Zone

Gist

Time zones divide the world into 24 segments, each about 15 degrees of longitude wide, to standardize time, as the Earth rotates 15 degrees every hour. They create uniform local times, offset from Coordinated Universal Time (UTC), allowing for synchronized schedules despite different sunrises/sunsets, with political boundaries often adjusting ideal 15-degree lines for practicality and some regions using Daylight Saving Time (DST).

Time zones are primarily based on the Earth's rotation and its division into 24 longitudinal sections, with each representing one hour of the day. The prime meridian, located at Greenwich, England (Greenwich Mean Time or GMT), serves as the starting point for defining time zones.

Summary

A time zone is an area which observes a uniform standard time for legal, commercial, and social purposes. Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because it is convenient for areas in frequent communication to keep the same time.

Each time zone is defined by a standard offset from Coordinated Universal Time (UTC). The offsets range from UTC−12:00 to UTC+14:00, and are usually a whole number of hours, but a few zones are offset by an additional 30 or 45 minutes, such as in India and Nepal. Some areas in a time zone may use a different offset for part of the year, typically one hour ahead during spring and summer, a practice known as daylight saving time (DST).

Details

Time zone is a zone on the terrestrial globe that is approximately 15° longitude wide and extends from pole to pole and within which a uniform clock time is used. Time zones are the functional basis of standard time and were introduced in the late 19th century as railways connected places that had differing local times.

Different time zones occur because of the way in which Earth spins. Earth rotates 360 degrees every 24 hours, and therefore different parts of the planet experience daylight and darkness at different times. To coordinate time with daylight, the globe is divided into 24 segments, each 15 degrees of longitude apart. The prime meridian in Greenwich, England, serves as the starting point for these divisions, creating a global framework for timekeeping.

While the theoretical model of time zones is straightforward, practical adjustments are often made to accommodate political, social, and economic factors. For instance, some regions have chosen to adopt time offsets of 30 or 45 minutes instead of the standard one-hour difference. These adjustments are made to better align with local solar time or to unify time within a country, as seen in places such as Newfoundland, Iran, and India.

Before the concept of time zones, each locality set its time based on the Sun’s position, leading to a chaotic array of local times. This system became impractical with the advent of rapid railway transportation in the late 19th century, which required a more uniform timekeeping system to avoid confusion in scheduling. The introduction of standard time zones was a solution to this problem, allowing regions to adopt a consistent time standard.

International Date Line is an imaginary line extending between the North Pole and the South Pole and arbitrarily demarcating each calendar day from the next. It corresponds along most of its length to the 180th meridian of longitude but deviates eastward through the Bering Strait to avoid dividing Siberia and then deviates westward to include the Aleutian Islands with Alaska. South of the Equator, another eastward deviation allows certain island groups to have the same day as New Zealand.

The International Date Line is a consequence of the worldwide use of timekeeping systems arranged so that local noon corresponds approximately to the time at which the sun crosses the local meridian of longitude. A traveler going completely around the world while carrying a clock that he advanced or set back by one hour whenever he entered a new time zone and a calendar that he advanced by one day whenever his clock indicated midnight would find on returning to his starting point that the date according to his own experience was different by one day from that kept by persons who had remained at the starting point. The International Date Line provides a standard means of making the needed readjustment: travelers moving eastward across the line set their calendars back one day, and those traveling westward set theirs a day ahead.

Coordinated Universal Time (UTC) is the international basis of civil and scientific time, which was introduced on January 1, 1960. The unit of UTC is the atomic second, and UTC is widely broadcast by radio signals. These signals ultimately furnish the basis for the setting of all public and private clocks. Since January 1, 1972, UTC has been modified by adding “leap seconds” when necessary.

UTC serves to accommodate the timekeeping differences that arise between atomic time (which is derived from atomic clocks) and solar time (which is derived from astronomical measurements of Earth’s rotation on its axis relative to the Sun). UTC is thus kept within an exact number of seconds of International Atomic Time and is also kept within 0.9 second of the solar time denoted UT1. Because of the irregular slowing of Earth’s rate of rotation by tidal friction and other forces, there is now about one more (atomic clock-derived) second in a solar year than there are UT1 seconds. To remedy this discrepancy, UTC is kept within 0.9 second of UT1 by adding a leap second to UTC as needed; the last minute of December or June is made to contain 61 seconds. The slowing of Earth’s rotation varies irregularly, and so the number of leap seconds by which UTC must be retarded to keep it in epoch with UT1 cannot be predicted years in advance. Impending leap seconds for UTC are announced at least eight weeks in advance by the International Earth Rotation and Reference Systems Service at the Paris Observatory, however.

Universal Time (UT), the mean solar time of the Greenwich meridian (0° longitude). Universal Time replaced the designation Greenwich Mean Time in 1928; it is now used to denote the solar time (q.v. : quod vide : which see) when an accuracy of about one second suffices. In 1955 the International Astronomical Union defined several categories of Universal Time of successively increasing accuracy. UT0 represents the initial values of Universal Time obtained by optical observations of star transits at various astronomical observatories. These values differ slightly from each other because of the effects of polar motion (q.v.). UT1, which gives the precise angular coordinate of the Earth about its spin axis, is obtained by correcting UT0 for the effects of polar motion. Finally, an empirical correction to take account of annual changes in the Earth’s speed of rotation is added to UT1 to convert it into UT2. Coordinated Universal Time (q.v.), the international basis of civil and scientific time, is obtained from an atomic clock that is adjusted in epoch so as to remain close to UT1; in this way, the solar time that is indicated by Universal Time is kept in close coordination with atomic time.

Standard Time, the time of a region or country that is established by law or general usage as civil time.

The concept was adopted in the late 19th century in an attempt to end the confusion that was caused by each community’s use of its own solar time. Some such standard became increasingly necessary with the development of rapid railway transportation and the consequent confusion of schedules that used scores of different local times kept in separate communities. (Local time varies continuously with change in longitude.) The need for a standard time was felt most particularly in the United States and Canada, where long-distance railway routes passed through places that differed by several hours in local time. Sir Sandford Fleming, a Canadian railway planner and engineer, outlined a plan for worldwide standard time in the late 1870s. Following this initiative, in 1884 delegates from 27 countries met in Washington, D.C., and agreed on a system basically the same as that now in use.

The present system employs 24 standard meridians of longitude (lines running from the North Pole to the South Pole, at right angles to the Equator) 15° apart, starting with the prime meridian through Greenwich, England. These meridians are theoretically the centres of 24 Standard Time zones, although in practice the zones often are subdivided or altered in shape for the convenience of inhabitants; a notable example of such alteration is the eastward extension of the International Date Line around the Pacific island country of Kiribati. Time is the same throughout each zone and differs from the international basis of legal and scientific time, Coordinated Universal Time, by an integral number of hours; minutes and seconds are the same. In a few regions, however, the legal time kept is not that of one of the 24 Standard Time zones, because half-hour or quarter-hour differences are in effect there. In addition, Daylight Saving Time is a common system by which time is advanced one hour from Standard Time, typically to extend daylight hours during conventional waking time and in most cases for part of the year (usually in summer).

Additional Information

Data spotlights represent data and statistics from a specific period of time, and do not reflect ongoing data collection. As individual spotlights are static stories, they are not subject to the Bureau of Transportation Statistics (BTS) web standards and may not be updated after their publication date. Please contact BTS to request updated information.

Before the establishment of time zones in 1883, there were more than 144 local times in North America. The resulting time differences between adjacent towns and cities were not critical when it took days to travel from place to place. With the proliferation of railroads, faster travel became possible across large geographies, and travelers could sometimes arrive at an earlier local time than they had departed. Due to this lack of time standardization, train scheduling proved difficult to coordinate, resulting in missed connections and collisions. As a result, the major railroad companies began to operate on a coordinated system of four time zones starting in 1883.

Because the development of standardized time was transportation-driven, the government coordination of time zones was handled by transportation agencies. In 1918, the federal organization in charge of railroad regulation — the Interstate Commerce Commission (ICC) — was given the power to address coordination concerns. That year, five time zones were officially adopted as the US entered World War I: the Eastern, Central, Mountain, Pacific, and Alaska zones, all of which are still in use today. However, the need for coordination among all transportation modes became increasingly important after World War II. When the Department of Transportation was created by Congress in 1966, it was assigned “the responsibility of regulating, fostering, and promoting widespread and uniform adoption and observance of standardized time” within each time zone.

Daylight Saving Time (DST) was enacted as a legal requirement by the Uniform Time Act of 1966. Motivated by transportation improvements, this act mandated standard time within the existing time zones and established a permanent system of uniform DST, including the dates and times for twice yearly transitions. While State governments cannot independently change time zones or the length of DST, they can exempt themselves from DST, independent of DOT authority or permission. Nonetheless, DST is observed uniformly across the nation except in American Samoa, Guam, Northern Mariana Islands, Puerto Rico, the Virgin Islands, Hawaii, and most of Arizona.

Today, the Department of Transportation continues to oversee standard time due to its historical and contemporary importance in transportation and associated commercial activity. Time zone boundaries, established by law, can only be changed by the Secretary of Transportation upon a determination that the proposed adjustment serves the “convenience of commerce.” Per DOT policy, a petition requesting such a change must come from the highest political authorities in a State or locality. Several communities have requested changes to their time zone designation over the past two decades, the most recent being Mercer County, North Dakota in 2010, which chose to switch from Mountain to Central Time. Authorizing these changes and keeping track of the legally designated time zone for each area of the U.S. are key facets of the DOT’s oversight of uniform time observance, time zones, and DST.

In 2019, the Bureau of Transportation Statistics (BTS), in coordination with the Office of the General Counsel, created a digital geographic representation of the official written time zone delineations defined in the Code of Federal Regulations (CFR), Title 49, Subtitle A, Part 71 - Standard Time Zone Boundaries. Currently the United States and its territories have 9 time zone boundaries: Atlantic, Eastern, Central, Mountain, Pacific, Alaska, Hawaii–Aleutian, Samoa, and Chamorro.

The DOT Time Zone Boundary Geospatial layer is the verified digital representation of the current time zone delineations as written in the CFR, and is part of the National Transportation Atlas Database (NTAD). This layer provides the American public with detailed, reliable, and authoritative information on time-related authorities and time zone boundaries.

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