My Science School

The Lakadong variety of turmeric grown in Meghalaya is drawing worldwide attention because of its high curcumin content. Curcumin is the pigment that gives turmeric its yellow colour and pungent smell. It has medicinal properties and is in demand in the pharmaceutical industry.

While most varieties of turmeric have a curcumin content of between 2% and 3%, the Lakadong variety has a curcumin content of about 7%. India is the world's largest producer of turmeric. Most of our country's turmeric is produced by Andhra Pradesh, Odisha and Tamil Nadu. The Lakadong variety which has high curcumin content is cultivated in a small region in East Jaintia Hills district.

Turmeric is a member of the ginger family. It is used to add flavour to food and in Ayurvedic medicine. It helps relieve arthritic pain and digestive problems. Its antioxidant and anti-inflammatory properties may help in treating cancers of the colon, skin and breast, and reduce incidence of Alzheimer's disease and heart disease.

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Sea waves constantly crash into coasts, crushing rocks and pebbles. Rising waves hurl small rocks onto seaside cliffs, eroding them or tearing away at their base until they collapse. Waves and water currents carry sand and gravel that can alter coastlines. The sea and its waves can certainly wear away the land.

Coastal erosion is the wearing away of the land by the sea often involves destructive waves wearing away the coast (though constructive waves also contribute to coastal erosion).

There are four main processes of coastal erosion. These are corrasion, abrasion, hydraulic action and attrition.

Corrasion is when destructive waves pick up beach material (e.g. pebbles) and hurl them at the base of a cliff. Over time this can loosen cliff material forming a wave-cut notch.

Abrasion occurs as breaking waves, concentrated between the high and low watermarks, which contain sand and larger fragments wear away the base of a cliff or headland. It is commonly known as the sandpaper effect. This process is particularly common in high-energy storm conditions.

Waves hitting the base of a cliff causes air to be compressed in cracks, joints and folds in bedding planes causing repeated changes in air pressure. As air rushes out of the cliff when the wave retreats it leads to an explosive effect as pressure is released. This process is supported further by the weakening effect of weathering. The material breaks off cliffs, sometimes in huge chunks. This process is known as hydraulic action.

Attrition is when waves cause rocks and pebbles to bump into each other and break up.

Credit: internet geography

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The Spanish soldiers who explored the region for the first time in 1541 battled native female warriors who fought bravely. The name the invaders gave to the river came from the Persian hamazan, meaning ‘those who fight together’ - also used in Greek mythology for outstanding women warriors.

Before the conquest of South America, the Rio Amazonas had no general name; instead, indigenous peoples had names for the sections of the river they occupied, such as Paranaguazu, Guyerma, Solimões, and others.

In the year 1500, Vicente Yañez Pinzon, in command of a Spanish expedition, became the first European to explore the river, exploring its mouth when he discovered that the ocean off the shore was freshwater. Pinzon called the river the Rio Santa Maria de la Mar Dulce, which soon became abbreviated to Mar Dulce, and for some years, after 1502, it was known as the Rio Grande.

Pinzon's companions called the river El Río Marañón. The word Marañón is thought by some to be of indigenous origin. This idea was first stated in a letter from Peter Martyr to Lope Hurtado de Mendoza in 1513. However, the word may also be derived from the Spanish word maraña; meaning a tangle, a snarl, which well represents the bewildering difficulties that the earlier explorers met in navigating not only the entrance to the Amazon, but the whole island-bordered, river-cut, and indented coast of what is now the Brazilian state of Maranhão.

The name Amazon arises from a battle that Francisco de Orellana had with a tribe of Tapuyas where the women of the tribe fought alongside the men, as was the custom among the entire tribe. Orellana derived the name Amazonas from the ancient Amazons of Asia and Africa described by Herodotus and Diodorus.

Credit: New World Encyclopedia

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The Amazon River or River Amazon of South America has a greater total flow than the next six largest rivers combined. It is sometimes known as The River Sea. The Amazon is also regarded by most geographic authorities as the second longest river on Earth, the longest being the Nile in Africa.

The drainage area of the Amazon in Brazil, called the Amazon Basin, is the largest on Earth. If the Basin were an independent country, it would have more than twice the area of India.

The quantity of fresh water released by the Amazon to the Atlantic Ocean is enormous: up to 300,000 m³ per second in the rainy season. The Amazon is responsible for a fifth of the total volume of fresh water entering the oceans worldwide. It is said that offshore of the mouth of the Amazon potable water can be drawn from the ocean while still out of sight of the coastline, and the salinity of the ocean is notably lower a hundred miles out to sea. This mixture of fresh and salt water is known as brackish water.

This quantity of water causes the Amazon to have no clouds above the channel near its mouth. These are usually taken in the morning, when water is colder and land is beginning to be much warmer. Above big rivers (the Orinoco and Caura rivers in Venezuela and many more have the same characteristic), cold waters create a high pressure air mass which make rivers easy to see through clouds. On the contrary, during afternoons, clouds cover most river channels.

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Colorado River, major river of North America, rising in the Rocky Mountains of Colorado, U.S., and flowing generally west and south for 1,450 miles (2,330 kilometres) into the Gulf of California in northwestern Mexico. Its drainage basin covers 246,000 square miles (637,000 square kilometres) and includes parts of seven states—Wyoming, Colorado, Utah, New Mexico, Nevada, Arizona, and California. For 17 miles the river forms the international boundary between the U.S. state of Arizona and Mexico. The river drains a vast arid and semiarid sector of the North American continent, and because of its intensive development it is often referred to as the “Lifeline of the Southwest.”

For more than a thousand miles of its course, the Colorado has cut a deep gorge. Where the river system is joined by lateral streams—the Virgin, Kanab, Paria, Escalante, Dirty Devil, and Green rivers from the west, and the Little Colorado, San Juan, Dolores, and Gunnison from the east—a transverse system of narrow, winding deep canyons has been cut. Each entering river and each lateral creek has cut another canyon, and thus the upper and middle parts of the Colorado basin are traversed by a labyrinth of deep gorges. The longest of these unbroken trunk canyons through which the Colorado flows is the spectacular Grand Canyon, extending from the mouth of the Paria to the Grand Wash Stream. Other canyons cut by the river include Marble Canyon, Glen Canyon, and Cataract Canyon. Canyonlands National Park encompasses another of these regions at the juncture of the Green and Colorado rivers in southeastern Utah.

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The Nile River flowing through Egypt could be six times as old as previously thought, according to a study which estimated it to have originated at least 30 million years ago. The study, published in the journal Nature Geoscience, assessed the links between the geographical and physical features — or topography — of the Nile River to the flow of molten rocks in the Earth’s mantle.

The researchers, including those from the University of Texas (UT) at Austin in the US, connected the tilted nature of the Nile’s topography to a conveyor belt of mantle rock pushing up against the Ethiopian Highlands in the south, and pulling the surface down in the north. This gentle gradient, they said, keeps the Nile on a consistent northward course from its beginning to the end. The study said the Nile would have turned west long ago — probably changing the course of history along with it — if it weren’t for the mantle movement keeping the river on course.

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A canyon is a vast, bounded valley with steep, rising sides. Canyons are formed by weathering and erosion. Over millions of years, the land is continuously worn away by water. Rocks and silt on the riverbed are carried away by the river, which further gouges out a narrow channel-shaped landscape.

A canyon is a deep, narrow valley with steep sides. “Canyon” comes from the Spanish word cañon, which means “tube” or “pipe.” The term “gorge” is often used to mean “canyon,” but a gorge is almost always steeper and narrower than a canyon.

The movement of rivers, the processes of weathering and erosion, and tectonic activity create canyons.

River Canyons

The most familiar type of canyon is probably the river canyon. The water pressure of a river can cut deep into a river bed. Sediments from the river bed are carried downstream, creating a deep, narrow channel.

Rivers that lie at the bottom of deep canyons are known as entrenched rivers. They are entrenched because, unlike rivers in wide, flat flood plains, they do not meander and change their course.

Weathering and Erosion

Weathering and erosion also contribute to the formation of canyons. In winter, water seeps into cracks in the rock. This water freezes. As water freezes, it expands and turns into ice. Ice forces the cracks to become larger and larger, eroding bits of stone in the process. During brief, heavy rains, water rushes down the cracks, eroding even more rocks and stone. As more rocks crumble and fall, the canyon grows wider at the top than at the bottom.

When this process happens in soft rock, such as sandstone, it can lead to the development of slot canyons. Slot canyons are very narrow and deep. Sometimes, a slot canyon can be less than a meter (3 feet) wide, but hundreds of meters deep. Slot canyons can be dangerous. Their sides are usually very smooth and difficult to climb.

Tectonic Uplift

Canyons are also formed by tectonic activity. As tectonic plates beneath the Earth’s crust shift and collide, their movement can change the area’s landscape. Sometimes, tectonic activity causes an area of the Earth’s crust to rise higher than the surrounding land. This process is called tectonic uplift. Tectonic uplift can create plateaus and mountains. Rivers and glaciers that cut through these elevated areas of land create deep canyons.

Credit: National Geographic Society

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Current refers to the speed of the movement of water. This can be very fast, especially in the mountains, close to the source of the river. River currents have tremendous power - they can tear out boulders and carry huge rocks and smash them deep into the riverbed. As the river reaches the plains, the current slows it down; causing it to deposit a lot of the debris it carried, creating a wider valley with fertile soil.

Rivers and streams begin their lives as smaller creeks, often called "the headwaters". These small tributaries flow downhill until they merge to form bigger tributaries, which continue merging to form larger rivers. Rivers keep flowing to lower altitudes, towards the oceans. River systems are similar to the blood vessels in your body. Tiny capillaries that carry blood keep merging together until all of the blood empties into large veins, which deliver the blood to your heart.

All rivers are surrounded by a certain amount of land that is higher in altitude (upgradient) than the actual river. Precipitation that falls in this area eventually flows downhill towards the river. At any particular point on a river, the land upgradient of the point is the river's watershed, or drainage basin. This example of a watershed gives a rough idea of how precipitation flows downhill into rivers (and lakes) movement of a fluid within a larger body of that fluid. Fluids are materials capable of flowing and easily changing shape. The most familiar natural fluid is water. But air is considered a fluid as well. Electricity can also flow as a current.

Air currents flow in the atmosphere, the layer of air surrounding the Earth. Water currents flow in rivers, lakes, and, oceans. Electric currents flow through power lines or as lightning.

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A river can originate from the end of a melting glacier or snow. It can also start from a lake or a spring. As it flows downstream, the river is joined by many tributaries, which increase its flow to make one large river. The land area that feeds, or drains into, a specific river and its tributaries is the watershed for that river system.

A watershed is an area of land that drains or “sheds” water into a specific waterbody. Every body of water has a watershed. Watersheds drain rainfall and snowmelt into streams and rivers. These smaller bodies of water flow into larger ones, including lakes, bays, and oceans. Gravity helps to guide the path that water takes across the landscape.

Not all rain or snow that falls on a watershed flows out in this way. Some seeps into the ground. It goes into underground reservoirs called aquifers. Other precipitation ends up on hard surfaces such as roads and parking lots, from which it may enter storm drains that feed into streams.

Watersheds can vary in size. A watershed for a tiny mountain creek might be as small as a few square meters. Some watersheds are enormous and usually encompass many smaller ones. The Mississippi River watershed is the biggest watershed in the United States, draining more than three million square kilometers (one million square miles) of land. The Mississippi River watershed stretches from the Appalachian Mountains in the east to the Rocky Mountains in the west. Thirty-one U.S. states and two Canadian provinces fall within the Mississippi River watershed.

Credit: National Geographic Society

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The Nile in Africa is the longest river in the world. The river has three tributaries; the two main ones are the White Nile that begins in Burundi and the Blue Nile that has its source in Ethiopia. Both rivers merge in Sudan. The third tributary, Atbara River, is dry most of the year and flows only if it rains in Ethiopia.

The Nile River, considered the longest river in the world, is approximately 4,258 miles (6,853 kilometers) long, but its exact length is a matter of debate. Flowing northward through the tropical climate of eastern Africa and into the Mediterranean Sea, the river passes through 11 countries: Tanzania, Uganda, Rwanda, Burundi, the Democratic Republic of the Congo, Kenya, Ethiopia, Eritrea, South Sudan, Sudan and Egypt.

The Nile has two major tributaries: the longer White Nile, considered the prime stream and headwaters; and the Blue Nile, which carries about two-thirds of the river's water volume and most of the silt.

The White Nile begins at Lake Victoria, Africa's largest lake, which touches the countries of Uganda, Kenya and Tanzania. But Lake Victoria isn't necessarily the most distant and "true" source of the Nile River because the lake itself has many feeder rivers coming in from the surrounding mountains. In 2006, a British explorer named Neil McGrigor said he'd traveled to the Nile’s most distant source at the beginning of the Kagera River, Lake Victoria’s longest feeder river.

Credit: Live Science

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The Wright brothers need no introduction. Best known for achieving the first powered heavier-than-air craft flight, the Wright brothers obtained the patent for a "Flying Machine" on May 22, 1906.

The names of Wilbur Wright and Orville Wright will forever be intertwined with the history of flying machines. For, the Wright brothers were the first to achieve the flight of a powered heavier-than-air craft.

 The elder of the two, Wilbur, was born in 1867 and was the third child in the Wright family. Orville was the sixth of seven children that his parents had. The seeds for an idea about flying were sown when Wilbur and Orville were still two young boys.

A toy that inspires

Their mother gave them a toy helicopter to play with. This little piece of wood that had two rubber bands to turn a propeller laid the foundation for a lifetime's work.

Drawn towards flying, the Wright brothers spent plenty of time observing birds in flight. This allowed them to notice that lift was created when birds soared into the wind and the air flowed over the curved surface of their wings. They use this knowledge to build kites, which they even sold to their friends.

Cycling to aviation

As avid cyclists, Wilbur and Orville owned a bicycle shop as adults. Despite the fact that they had less than 10 years of combined high school education, the experience of building bicycles provided them the understanding of early engine design - be it using chains, sprockets, or ball bearings.

Years of riding a bicycle gave them ideas as to how they could control and balance an aircraft. Add to this the countless hours that they had spent observing flight in nature and they had the necessary knowledge and interest to get started.

By 1899, the Wright brothers ventured into flying. Between 1900 and 1902, they researched every aspect of flight, from roll, pitch, and yaw to the rudder, elevator, and performance of the wing. In order to test the aerodynamic qualities of wing models, they even developed the first wind tunnel. The brothers also worked on their own piloting skills by making over a thousand flights on a series of gliders at Kitty Hawk, North Carolina.

Master a control system

Their years of trial and error allowed them to master their glider in all three axes of flight: pitch, roll, and yaw. While the pitch was operated by a forward elevator, their breakthrough discovery included the simultaneous use of roll control with wing-warping and yaw control with a rear rudder.

Even though they had just started conducting experiments with propellers and begun to build their own engines, they applied for a patent in March 1903 for their control system. They were granted U.S. Patent 821,393 for a "Flying Machine" on May 22, 1906. This patent is significant as it laid down a useful and modern means of controlling a flying machine, regardless of whether it was powered or not.

Not ones to be kept waiting, the Wright brothers had already made the first free, controlled, and sustained flights in a powered, heavier-than-air craft on a chilly day at Kitty Hawk, on December 17, 1903. With just a handful of others witnessing history, Orville stayed 12 seconds in the air and flew 120 feet in the first trial at 10.35 a.m. In the fourth and final trial of the day, Wilbur achieved the longest flight of 59 seconds in the air and reached a height of 852 feet. In a little over 100 years since then, human beings have flown farther and faster than ever before, and continue to progressively get better at it.

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August 13 is observed as World Organ Donation Day to spread awareness about the importance of organ donation.

This day strives to encourage people to donate their healthy organs after death in order to save more lives. Donating organs like the kidneys, heart, pancreas, eyes, lungs, etc can help save the lives of those who are suffering from chronic illnesses. Numerous people lose their lives due to the unavailability of healthy organs that could save them. This day aims to help people realise that volunteering to donate their organs after death can be life-changing for many.

First organ donation and a Nobel Prize

Modern medicine has evolved significantly and has made it possible for organs to be transplanted from one person to another and enables them to live a healthy life. The first-ever successful living donor organ transplant was done in 1954 in the United States. Doctor Joseph Murray won the Nobel Prize in Physiology and Medicine in 1990 for successfully carrying out a kidney transplant between twin brothers Ronald and Richard Herrick.

Who can volunteer to be an organ donor?

Donating one's organs is giving someone a new life, anyone can volunteer to be an organ donor irrespective of their age, caste, and religion. It is, however, important to ensure that those volunteering to donate their organs do not suffer from chronic diseases like HIV, cancer, or any heart and lung disease. A healthy donor is of paramount importance. One can sign up to be a donor once they reach 18 years of age.

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In 1954, the kidney was the first human organ to be transplanted successfully. Until the early 1980s, the potential of organ rejection limited the number of transplants performed.

 The first ever successful transplant of any organ was done at the Brigham & Women's Hospital in Boston, Ma. The surgery was done by Dr. Joseph Murray, who received the Nobel Prize in Medicine for his work. The reason for his success was due to Richard and Ronald Herrick of Maine. Richard Herrick was a in the Navy and became severely ill with acute renal failure. His brother Ronald donated his kidney to Richard, and Richard lived another 8 years before his death. Before this, transplant recipients didn't survive more than 30 days. The key to the successful transplant was the fact that Richard and Ronald were identical twin brothers and there was no need for anti-rejection medications, which was not known about at this point. This was the most pivotal moment in transplant surgery because now transplant teams knew that it could be successful and the role of rejection/anti-rejection medicine.

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When a river flows through low-lying plains, it slows down, carving out a meandering path with many U-shaped curves. Over time, some of these curves become cut off from the main flow of the river by the build-up of silt deposits, and form oxbow lakes. These distinctive, curved water bodies are close to a river but separate from it.

An oxbow lake starts out as a curve, or meander, in a river. A lake forms as the river finds a different, shorter, course. The meander becomes an oxbow lake along the side of the river.

Oxbow lakes usually form in flat, low-lying plains close to where the river empties into another body of water. On these plains, rivers often have wide meanders.

Meanders that form oxbow lakes have two sets of curves: one curving away from the straight path of the river and one curving back. The corners of the curves closest to each other are called concave banks. The concave banks erode over time. The force of the rivers flowing water wears away the land on the meanders concave banks.

The banks opposite the concave banks are called convex banks. The opposite of erosion happens here. Silt and sediment build up on convex banks. This build-up is called deposition.

Erosion and deposition eventually cause a new channel to be cut through the small piece of land at the narrow end of the meander. The river makes a shortcut. Oxbow lakes are the remains of the bend in the river.

Oxbow lakes are stillwater lakes. This means that water does not flow into or out of them. There is no stream or spring feeding the lake, and it doesnt have a natural outlet. Oxbow lakes often become swamps or bogs, and they often dry up as their water evaporates.

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Organ transplantation is a medical procedure in which an organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organs may be transported from a donor site to another location. Organs and/or tissues that are transplanted within the same person's body are called autografts. Transplants that are recently performed between two subjects of the same species are called allografts. Allografts can either be from a living or cadaveric source.

Organs that have been successfully transplanted include the heart, kidneys, liver, lungs, pancreas, intestine, thymus and uterus. Tissues include bones, tendons (both referred to as musculoskeletal grafts), corneae, skin, heart valves, nerves and veins. Worldwide, the kidneys are the most commonly transplanted organs, followed by the liver and then the heart. Corneae and musculoskeletal grafts are the most commonly transplanted tissues; these outnumber organ transplants by more than tenfold.

Organ donors may be living, brain dead, or dead via circulatory death. Tissue may be recovered from donors who die of circulatory death, as well as of brain death – up to 24 hours past the cessation of heartbeat. Unlike organs, most tissues (with the exception of corneas) can be preserved and stored for up to five years, meaning they can be "banked". Transplantation raises a number of bioethical issues, including the definition of death, when and how consent should be given for an organ to be transplanted, and payment for organs for transplantation. Other ethical issues include transplantation tourism (medical tourism) and more broadly the socio-economic context in which organ procurement or transplantation may occur. A particular problem is organ trafficking.[5] There is also the ethical issue of not holding out false hope to patients.

Transplantation medicine is one of the most challenging and complex areas of modern medicine. Some of the key areas for medical management are the problems of transplant rejection, during which the body has an immune response to the transplanted organ, possibly leading to transplant failure and the need to immediately remove the organ from the recipient. When possible, transplant rejection can be reduced through serotyping to determine the most appropriate donor-recipient match and through the use of immunosuppressant drugs.

Credit : Wikipedia 

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