Category Science

Which part of the eye does glaucoma affect?

Glaucoma is a group of eye conditions that damage the optic nerve, the health of which is vital for good vision. This damage is often caused by an abnormally high pressure in your eye. Many forms of glaucoma have no warning signs. The effect is so gradual that you may not notice a change in vision until the condition is at an advanced stage.

Glaucoma is the result of damage to the optic nerve. As this nerve gradually deteriorates, blind spots develop in your visual field. For reasons that doctors don’t fully understand, this nerve damage is usually related to increased pressure in the eye.

Glaucoma tends to run in families. In some people, scientists have identified genes related to high eye pressure and optic nerve damage. Promptly go to an emergency room or an eye doctor’s (ophthalmologist’s) office if you experience some of the symptoms of acute angle-closure glaucoma, such as severe headache, eye pain and blurred vision.

 

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What was recently found in the ocean?

Scientists discovered a new species of marine creature in the deepest trench on Earth. In a normal scenario, this would have called for celebration. But this situation isn’t normal. Because the researchers also identified plastic in its body.

The amphipod is just two inches long and was caught at a depth of 20,000 feet in the Mariana Trench. The Mariana Trench in the Pacific Ocean is the deepest point on Earth’s surface, reaching more than 36,000 feet deep. Clearly, even this remote environment is not exempt from the impact of plastic pollution. The tiny creature had been found to have ingested tiny pieces of debris known as microplastics. The material they identified was polyethylene terephthalate (PET), common plastic widely used in food and drink packaging. To highlight the scale of marine plastic pollution crisis, researchers decided to name it Eurythenes plasticus. The creature is now one of the 240 known species to have been recorded ingesting plastic.

Plastic debris is now common throughout the world’s oceans. In fact, a 2015 study found that around eight million tones of the material enter the oceans every year. Once in water, this plastic can break down into smaller and smaller pieces, eventually becoming microplastics – frequently ingested by marine animals. Thousands of animals, from sea birds to whales, die every year from consuming or getting caught in plastic.

 Pollution in Alarming scale

  • According to a 2017 study, humans have produced 18.2 trillion pounds of plastic since the 1950s. Only 9% of it has been recycled and another 12% has been burnt. A majority of the plastic ends up in landfills and the oceans. The debris is often carried by wind and rain into our drainage networks and eventually into the sea.
  • A report released by Ellen MacArthur Foundation at the World Economic Forum in 2016 estimated that at least eight million tones of plastics leak into the ocean – this is equal to dumping the contents of one garbage truck into the ocean every minute. The report further says the ocean is expected to contain one tonne of plastic for every three tonnes of fish by 2025, and by 2025, there will be more plastic than fish by weight in the ocean.

What are microplastics?

Most plastic in the ocean break down into very small particles called microplastics and make their way into the system of marine animals. Plastic particles that are less than five mm long are called microplastics. Microplastics come from a variety of sources, and are of two types – one that are manufactured (microbeads) and the other that are derived from the breakdown of larger plastic debris. Besides water, microplastics have been found in soil and air.

How plastic affects marine ecosystem

Sea turtles and other marine creatures mistake plastics for food (such as jellyfish) and ingest them. This causes blockage in their digestive system, leading to their death. Studies have found that plastic pollution can also affect sea turtles’ reproductive system.
In sea birds, plastic ingestion reduces the storage volume of the stomach, causing starvation and death.
Besides ingestion, marine mammals get tangled up in plastic, leading to their death.
Plastic may also get transferred along the food chain – from fish to bigger fish or marine mammals and finally to human seafood consumers.

Invisible threat

Marine species also face the invisible threat of plastic-derived chemicals. It was long held that plastic broke down only at very high temperatures and over hundreds of years. A study in 2009 showed that some plastics decompose rapidly in the ocean, even within a year of the trash hitting the water. The degrading plastics also leach potentially toxic chemicals such as bisphenol A into the seas, possibly threatening ocean animals, and human, who ultimately consume some of these creatures.

  • Direct toxicity of plastics comes from lead, cadmium and mercury added to them while manufacturing plastic products. These toxin s have been found in many fish in the ocean.
  • When expanded polystyrene, used especially for making food containers, breaks down, the tiny polystyrene components start to sink, as they are heavier than water. Exposure to polystyrene can cause irritation of the skin, eyes and the upper respiratory tract in humans. Acute exposure may also result in gastrointestinal effects.
  • Bisphenol A (BPA) has been shown to interfere with the reproductive systems of animals. In humans, even low doses of bisphenol A can impair immune function and cause cancer, obesity, diabetes and hyperactivity, among other problems.
  • Diethylhexyl phthalate (DEHP) contained in some plastics, is also carcinogenic (cancer-causing).

 

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Why are Locusts causing so much of international anguish?

Locusts are large insects. They are special grasshoppers. They have big hind legs used for jumping. All grasshoppers (except the long-horned, ones) belong to the Acridoidea family, and the most important Locusts are all in the family Acrididae. Locusts can change their habits and, behaviour when they occur in large numbers their numbers rise they stay together in dense groups called, “swarms.” These are groups of adults. Locust groups are called “bands” when; they consist of the wingless young ones, commonly called ‘hoppers’. Locust swarms migrate over great distances, and, this behaviour differentiates them from other grasshoppers. When, locusts are in small numbers they live their individual lives like ordinary grasshoppers. These could be small groups that stay in one place. Some species of locusts are regarded as intermediate between grasshoppers that live alone and typical locusts that do not.

Locusts have the capacity to multiply rapidly and produce groups or swarms in special circumstances. Their population explosion can be started by unusual weather conditions or changes in land use. This is what happened this year. According to the UN, the heavy infestation this year can be traced back to cyclone season of 2018-19 that brought heavy rains to the Arabian Peninsula. This allowed at least three generations of “unprecedented breeding” and no one noticed it. Swarms have since spread out into South Asia and East Africa. David Phiri, a FAO regional, coordinator said that whew weather conditions are good for locust breeding, there is a high probability that the insects will continue to spawn rapidly. This year it may go on till April. Locusts have probably been man’s enemies ever since humans began to grow crops. The Old Testament (Bible) and the Koran mention the desert Locust. You can see carved, images of Locusts in Sixth Dynasty (2420-2270 BC) tombs at Saqqara in Egypt. Now, in countries like Somalia, Locusts can determine whether people will have sufficient food or starve. The damage they cause can be mild to very severe. This depends on whether the swarms are moving about quickly or whether they stay for several days in one area.

FAO describes the desert Locust, schistocerca gregaria, as the world’s “most dangerous migratory pest, with a, voracious appetite unmatched in the insect world.” Swarms can vary from, less than 1 sq km (0.38 square miles) to several, hundred. Each square kilometre can contain at Least 40 million insects, according to FAO. FAO’s Western Africa joint Locust control force was established, in 2016 and includes Mauritania, Algeria, Burkina Faso, Morocco, Niger, Senegal, Chad, Libya, and Mali.

 

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What are locusts and how do they pose a threat to food security?

The word “locust’ has been in the environment sections of all newspapers for some time. On some days, news about them appeared on the front page. Here are samples.

[1] ‘The UN’s Food and Agriculture Organisation (FAO) said earlier this week that Somalia and Ethiopia were facing a Locust infestation that is destroying crops and threatening food security in the region. On Saturday, Somali farmers urged their government and the international community to help protect crops from the invasion.”

[2] ‘The FAO has reported farmers are facing “devastating threat” to their crops.” “A single locust plague can lead to a loss of 170,000 tonnes of grain, enough to feed one million people for a year,” the organisation said. The insects have already destroyed at least 175,000 acres of farmland in Somalia and Ethiopia, according to the FAO.

[3] A swarm of what appeared to be locusts forced a passenger plane off its course in Ethiopia. Pilots were preparing to land the Ethiopian Airlines flight from Djibouti to Dire Dawa when clouds of insects slammed into the plane’s engines, wind-shield and nose. They tried in vain to clean the windscreen with the plane’s wipers. Thirty minutes later the plane landed safely in the capital Addis Ababa.”

[4] “Somalis fight invading Locusts by eating them. Somalis are battling the worst invasion of Locusts in 25 years. They have resorted, to eating the insects to stop them from destroying crops. Local media reports have shown, residents central Somalia frying Locusts and serving them with rice, with one man staging the desert insects are tastier than fish.. Another man told Universal Somali TV he believes eating the insects could, help reduce his back pain and blood pressure, while some residents have apparently urged local restaurants to introduce locust dishes.”

[5] “Mauritania is planning to use drones to monitor the Locust swarms in the locust swarms in their country.” ‘The drones will track and monitor desert Locusts and instigate early-warning operations before the swarms arrive so that appropriate action can be taken,” said a report. The Latest round of tests, announced, in September 2019, will represent a “critical stage” in the fight against the locust plague, Secretary-General of the Mauritanian Rural, Development Ministry Ahmedou , Ould Bouh said.

This year’s tests are expected to confirm whether improvements made to drones wilt demonstrate their usability in the harsh desert conditions, and pave the way for their wider use in the region.

[6] “Pakistan declared an emergency earlier in February, 2020, saying locust numbers were the worst in, more than two decades. The Chinese government announced, recently it was sending a team of experts to Pakistan to develop “targeted programmes” against the Locusts.” They would send ducks to control the numbers of Locusts. “An agricultural expert behind the scheme says a single duck can eat more than 200 locusts a day and can be more effective than pesticides. Lu Lizki, a senior researcher with the Zhejiang Academy of Agricultural Sciences said that the ducks are “biological weapons”. He said that while chickens could eat about 70 Locusts in one day a duck could devour more than three times that number. After a trial, the ducks would be sent to Pakistan’s worst-affected areas of Sindh, Balochistan and Punjab provinces. “China could, deploy 100,000 ducks to neighbouring Pakistan to help tackle swarms of crop-eating locusts.”

However, a professor from the China Agriculture University, who is part of the delegation to Pakistan, questioned, whether the ducks would be suited to the mainly arid conditions where the Locusts are a problem. “Ducks rely on water, but in Pakistan’s desert areas, the temperature is very high,” Zhang Long told reporters in Pakistan.”

 

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What do we know about KIC-7340288 b and other exoplanets discovered last month?

The world beyond our own has always been a subject of curiosity and fascination. Space exploration projects over the years have succeeded in understanding the universe better. What are other planets in our solar system like? Do aliens realty exist? If so, where could they possibly live? These are some of the questions the projects have been constantly trying to seek answers to.

The Kepler Space Telescope was launched, in, 2009 to find answers to one such question, — how many earth-sized planets are there in the habitable zones of other stars in the Milky Way? The space observatory outlived its initial planned Lifetime of three-and-a-half years. It was retired, in October 2018. In its nine years of operation, Kepler discovered 2,662 planets and revealed, vital details about planetary systems.

Now, combing through data from Kepler, Michelle Kunivnoto, a PhD candidate of astronomy at the University of British Columbia, has discovered 17 new planets. This includes a potentially habitable Earth-sized world, named, KIC-7340288 b.

What are exoplanets?

On a clear night sky, you see thousands and thousands of stars. About 200 to 400 billion stars make up our galaxy, the Milky Way. We know quite a bit about Earth and other planets that orbit the Sun. Do other stars have planets orbiting them? Yes, they do. Astronomers have discovered about 3,694 such planets in more than 2,000 star systems since 1995.

These planets which are outside the solar system and orbiting a star are called exoplanets (extra+solar planets). There are also those that are outside a star system. They are called rogue exoplanets.

What do we know about KIC-7340288 b and other exoplanets discovered last month?

KIC-7340288 b, about 1,000 light-years away from, Earth, is in the habitable zone of its star. It is just one and a half times the size of Earth – small enough to be considered, rocky, instead of gaseous like the giant planets of the solar system.

A year on KIC-7340288 b has 142 days. It orbits its star at 0.444 Astronomical Units (AU, the distance between Earth and the Sun) – just bigger than Mercury’s orbit in our solar system.

The planet gets about a third of the tight that Earth gets from the Sun.

Of the other 16 new planets discovered, the smallest is only two-thirds the size of Earth. It is one of the smallest planets to be found with Kepler so far.

Who is Michelle Kunimato?

Michelle Kunimoto is a doctoral candidate of astronomy at the University of British Columbia. This isn’t the first time Kunimoto has discovered planets. She found four while she worked on her undergraduate degree.

How did Kepler detect planets?

When a planet passes in front of a star, the event is called a “transit. On Earth, we can observe an occasional Venus or Mercury transit. These are seen as a small black dot travelling across the Sun as the planet (Venus or Mercury) passes between the Sun and us, blocking sunlight. The Kepler detected planets using this transit method, that is, the telescope spotted planets by looking for tiny dips in the brightness of a star caused by the planets’ transit.

Kepler first carried out its work by staring at more than 1,50,000 stars simultaneously. Once a planet is detected, its orbital size, temperature and the temperature of its parent star are calculated to find out if the planet is habitable.

The Kepler mission warranted that the stars be monitored and their brightness be measured continuously for transits. This meant that the Sun should not block the field of view of the telescope. Hence for the first four years, Kepler was pointed, to a field in the constellations of Cygnus, Lyra, and, Draco, which are well out of the ecliptic plane of the Sun.

What makes a planet habitable?

››Energy, carbon and Liquid water are the most important factors for Life to exist.

» Life possibility depends on whether the planet exists within the habitable zone. The habitable zone around a star is the range of distance within which temperatures allow water (essential for life) to remain Liquid on the surface of a planet.

» The host star should, be stable. Its Luminosity should not be too severe to burn up the planet.

» The planet must be made up of rocks, and not gases.

» It should not have a very tow mass. Low mass means Low gravity. Low gravity cannot retain atmosphere. Further, the atmosphere should have a protective Layer of essential gases.

» A rapidly rotating magnetic field to protect the planet from flares from nearby stars, is also vital.

What is the basis on which exoplanets are named?

Exoplanets orbiting a single star are christened by taking the name of the parent star and adding a tower case Letter to it. The first planet discovered in a system is given the designation “b” (the parent star is considered to be “a”) and Later planets are given subsequent Letters.

 

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Which was the first modular space station?

The International Space Station (ISS) is a habitable artificial satellite in low Earth orbit. A joint effort by participating space agencies, ISS serves as a space environment research laboratory. In terms of design, the ISS belongs to the third generation that allows modules to be added or removed from the existing structure, thereby allowing for greater flexibility.

The three generations

The first generation of space stations such as Soviet Union’s Salyut 1 and the U.S. Skylab had monolithic designs that consisted of one module with no resupply capability. The second generation of space stations, such as Soviet Union’s Salyut 6 and Salyut 7, consisted of a monolithic station, but with ports to allow resupply cargo spacecraft. The third generation, which are called modular space stations and now includes the ISS, correspond to those with more than one primary spacecraft that are launched independently and docked in space.

Soviet Union’s Mir space station marked the beginning of the third generation of space station design. The name “Mir” can be translated from Russian to mean “peace”, “world” or “village” – an apt choice for a space station that hosted people of various nationalities.

Different modules

On February 20, 1986, the assembly process began with the launch of Mir’s core module into orbit. Kvant 1 (1987), an astrophysics laboratory; Kvant 2 (1989), an augmentation module containing supplementary life-support equipment; Kristall (1990), a technology module that served as a materials-sciences lab; Spektr (1995), a power module that also allowed for remote observation of Earth’s environment; a docking module (1995); and Priroda (1996), Earth sensing module for experimenting with remote sensing; were the different modules launched and added to Mir over a decade.

Mir, however, started hosting humans even as more and more modules were added to it. Starting from March 1986, when the first crew docked with Mir, up until June 2000, when the last occupants left the space station, Mir received crew members from a number of expeditions. During its 15-year space flight, Mir played host to over 100 people from 12 different countries.

Exceeds expectations

When the Mir space station was designed and launched, it was built for a five-year life span. The Soviet Union broke down and Mir was operated by the new Russian Federal Space Agency after 1991, but it endured for almost another decade.

A series of problems, both technical and structural, caught up with Mir as years went on. Despite these failures and some accidents, it remained in operation. It was only in November 2000 that the Russian government decided to decommission the space station.

Planned re-entry

On January 24, 2001, a Russian Progress cargo ship carrying double the normal amount of fuel rendezvoused with Mir. Once the docking took place, Progress fired its thrusters to push the station into a controlled descent, thereby utilizing the extra fuel.

On March 23, 2001, Mir ceased to exist as it broke up in the Earth’s atmosphere upon re-entry. Airlines rerouted their Pacific flights and ships were warned ahead as a safety precaution. It proved to be unnecessary as the debris that did not burn up crashed into the south Pacific Ocean at the planned target zone, causing no harm to anyone.

Lucid’s tryst with Mir

On March 23, 1996, U.S. astronaut Shannon Lucid transferred to Mir from the space shuttle Atlantis for a planned five-month stay.

The first American woman to live in a space station, Lucid was also the first U.S. astronaut on an extended stay on the Mir.

As a biochemist, Lucid carried out a number of scientific experiments aboard Mir during her stay.

Her return was delayed owing to a number of reasons. She eventually made her return flight, again on Atlantis, and was back on Earth on September 26, 1996.

Her 188-day sojourn in space was a record then for time spent in space, both for women and Americans.

 

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