Is Indian Ocean helping Atlantic currents?
Topic: GS-I: Geography
In the Atlantic operates a large system of ocean currents, circulating the waters between the north and the south. Called Atlantic Meridional Overturning Current, or AMOC, it ensures the oceans are continually mixed, and heat and energy are distributed around Earth.
- For the last 15 years, however, scientists have been worried by signs that AMOC may be slowing, which could have drastic consequences on global climate.
- Now a new study suggests that AMOC is getting help from the Indian Ocean. Warming as a result of climate change, the Indian Ocean is causing a series of cascading effects that is providing AMOC a jump start.
How AMOC works
- As warm water flows northwards in the Atlantic, it cools, while evaporation increases its salt content. Low temperature and a high salt content raise the density of the water, causing it to sink deep into the ocean. The cold, dense water deep below slowly spreads southward. Eventually, it gets pulled back to the surface and warms again, and the circulation is complete. This continual mixing of the oceans, and distribution of heat and energy around the planet, contribute to global climate.
- Another oceanic system, the El Niño-Southern Oscillation (ENSO). This involves temperature changes of 1°-3°C in the central and eastern tropical Pacific Ocean, over periods between three and seven years. El Niño refers to warming of the ocean surface and La Niña to cooling, while “Neutral” is between these extremes. This alternating pattern affects rainfall distribution in the tropics and can have a strong influence on weather in other parts of the world.
What is happening now?
- AMOC has been stable for thousands of years. Data since 2004, as well as projections, have given some scientists cause for concern. What is not clear, however, is whether the signs of slowing in AMOC are a result of global warming or only a short-term anomaly.
Indian Ocean’s role
- As the Indian Ocean warms faster and faster, it generates additional precipitation. This draws more air from other parts of the world to the Indian Ocean, including the Atlantic. With so much precipitation in the Indian Ocean, there will be less precipitation in the Atlantic Ocean. Less precipitation will lead to higher salinity in the waters of the tropical portion of the Atlantic — because there won’t be as much rainwater to dilute it. This saltier water in the Atlantic, as it comes north via AMOC, will get cold much quicker than usual and sink faster.
- This would act as a jump start for AMOC, intensifying the circulation. If other tropical oceans’ warming, especially the Pacific, catches up with the Indian Ocean, the advantage for AMOC will stop.
Marsiya poetry in India
Topic: GS-I: Indian Heritage and Culture
On Friday, former Vice President Hamid Ansari, while addressing the function ‘Dastan-e-Marsiya: Karbala Se KashiTak’ in New Delhi, praised the Marsiya tradition of Urdu poetry, calling the art form an important part of ‘Adab’ (etiquette).
The Marsiya tradition of Urdu poetry
- The word Marsiya means elegy, meaning a poem which is a lament for the dead. In Urdu literature, Marsiya is written principally in praise of Imam Hussain, the grandson of the Prophet, and his family members who died at the Battle of Karbala in the year 680 CE in present-day Iraq.
- The Marsiya tradition first evolved in Delhi and the Deccan, but reached its zenith under the patronage of the Nawabs of Lucknow, who encouraged the art form in the 18th and 19th centuries around the same time when Mughal power was steadily receding.
- Its most iconic poets from the 19th century, Mir Anis and MirzaDabir, made a profound impact on Marsiya, making six-line stanzas the preferred form.
- Marsiya is also noteworthy for its depiction of events in 7th century Arabia in a manner which could be relatable to audiences in South Asia, making the genre popular here.
- For example, its Arab characters are depicted in the South Asian setting, having habits and customs like elite North Indian families. According to Hyder, Marsiya is usually sung, and set to Indian Ragas, creating a fusion of music and poetry.
Frequencies of sounds and its effect on brain
Topic: GS–II: Health
Neuroscientists from the University of Geneva (UNIGE) and Geneva University Hospitals (HUG) have now sought to analyse what goes on in the brain when people hear these frequencies. Their results, published in Nature Communications, have identified which frequencies are perceived as rough.
- The researchers conducted experiments with participants who were made to listen to various sounds with frequencies between 0 and 250 Hz. “We then asked participants when they perceived the sounds as being rough (distinct from each other) and when they perceived them as smooth (forming one continuous and single sound),” researcher Luc Arnal said in a statement released by UNIGE.
- The researchers were able to establish that the upper limit of sound roughness is around 130 Hz, while the sounds considered intolerable were mainly between 40 and 80 Hz. When sounds are in the smooth range, the conventional auditory system is activated. But when sounds are perceived as harsh (especially in the 40-80 Hz range), they induce a persistent response that additionally recruits a large number of cortical and sub-cortical regions that are not part of the conventional auditory system. These regions are related to aversion and pain, Arnal said in the university statement.
- This is the first time that sounds between 40 and 80 Hz have been shown to mobilise these neural networks, although these frequencies have been used for a long time in alarm systems.
Doctors issue warning against heartburn drug
Topic: GS–II: Health
Days after drugmakers and global public health regulators claim to have taken steps to remove supplies of a popular heartburn medication currently under invesigation the by U.S. Food and Drug Administration (FDA) for the presence of human carcinogen called NDMA, or N-Nitrosodimethylamine in Zantac and its generic forms, doctors in India too have cautioned the general public about this popular drug and asked for an urgent advisory by the Indian drug regulator.
More in news:
- In India Ranitidine (some versions of Zantac is is also known by the generic name ranitidine) is used for treating gastrointestinal disorders and discomfort.
- The news regarding the presence of NDMA in Ranitidine is disturbing. Ranitidine remains the most commonly prescribed medicine for acid peptic disorders and has generally been considered safer than many other medicines.
Delhi, Dhaka to boost maritime ties
Topic: GS –II: International relations
India will join Bangladesh to commemorate 100 years of ‘Bangabandhu’, the founding father Sheikh Mujibur Rahman, in 2020, and an International Fleet Review in 2021 to mark 50 years of the Liberation of Bangladesh.
More in news:
- In 1971, before the Liberation War, MuktiBahini with training and assistance from India had launched attacks on Pakistan Navy vessels along Mongla, Chittagong and other areas in then East Pakistan.
- Top among the discussions would be the proposal to bring Bangladesh into India’s coastal radar chain network which several countries in the region have already joined.
- The issue of coastal radar chain network in Bangladesh will be discussed to fast-track it, defence and diplomatic sources confirmed. A Bharat Electronics Ltd. (BEL) team went there recently and a Memorandum of Understanding (MoU) was signed and if all goes well, it could be signed in the next high-level bilateral visit.
- As part of its foreign cooperation initiatives, the Navy already imparts extensive training to Bangladesh at all levels and also provides assistance in hydrography among others. As Dhaka looks to expand its domestic ship building industry, India has offered assistance in ship design.
- The Chittagong Dry Dock Limited is looking to build six frigates for which India has offered to build some under the $500-million Line of Credit to boost ‘Make in India’ efforts and also assist in building some locally.
Topic: GS–II: Health
Since 2012, September is being observed as World Alzheimer’s Month meant to spread awareness about the disease, while September 21is observed as World Alzheimer’s Day.
- Alzheimer’s disease is a progressive brain disorder that usually appears in individuals who are in their mid-60s. Very rarely, it may occur in individuals younger than 65 years of age, when it is referred to as early onset Alzheimer’s.
- The disease was first described by Alois Alzheimer in 1906 and manifests itself by disrupting the message carrying neurotransmitters after it destroys brain cells and nerves. A person with Alzheimer’s also loses the ability to perform day-to-day tasks.
- According to the US-based Alzheimer’s Association, there are over 4 million people in India who suffer from some form of dementia.
Alzheimer’s disease vs dementia
- Dementia is a syndrome and not a disease, which Alzheimer’s is. The two are, however, closely related. Dementia’s various symptoms include loss of memory, thinking skills, problems with language, changes in the mood, deterioration in behaviour and an individual’s ability to perform everyday activities. It is most commonly caused by Alzheimer’s disease, which accounts for dementia in over 50-75% of the cases. Dementia can be caused by other diseases such as Parkinson’s and Huntington’s disease as well. It also has types, such as Lewy body and vascular dementia. As per the ADI report, the global costs of dementia have reached to over $1 trillion. The figure is expected to double by 2030.
- According to ADI, there are over 50 million people in the world living with dementia and 58 per cent of these people live in low-middle income countries. The numbers are expected to rise to over 152 million by 2050. Much of the burden of the disease will be on developing and highly populated countries such as India, China and countries in Latin America, where fewer than 10 per cent of the people with the disease receive a diagnosis.
Causes of Alzheimer’s
- The exact causes of Alzheimer’s are not yet known. The World Alzheimer Report 2018 notes that there is, however, some degree of consensus among scientists that the disease involves two proteins — beta-amyloid and tau. When the former reaches abnormal levels, it forms plaque that deposits itself between neurons, disrupting cell function. Tau too reaches abnormal levels, as a result of which it forms “neurofibrillary” tangles inside neurons, blocking the transport system of neurons. But scientists do not know what causes these proteins to reach abnormal levels in the first place. It is possible that the reasons could be genetic. The report further refers to a Lancet report from 2017, which claimed that lifestyle factors such as diet, physical fitness, smoking, alcohol are related to one-third of Alzheimer’s cases.
- A fully accurate diagnosis of dementia can only be made by examining the brain after death. Therefore for an individual who shows signs of dementia, doctors are only able to make a “reasonably accurate” diagnosis by referring to a person’s case history and symptoms.
Indians’ attitude to dementia
- Globally, two in three people think that dementia is caused by normal ageing and 95 per cent of the general public think that they can develop dementia at some point in their lives.
- According to the report, 23.4 per cent of Indians with dementia make an effort to keep their dementia a secret when meeting with people. And 7.4 per cent of healthcare practitioners with dementia do the same. Also, 24.3 per cent of the general public perceive people with dementia as “dangerous” and 14.6 per cent healthcare practitioners perceive the same. Of the surveyed Indians, 85.8% said they would take a genetic profiling test to find out if they were at the risk of developing dementia.
Is Alzheimer’s curable?
- At present, both Alzheimer’s disease and most causes of dementia have no cure and as a result, are irreversible. The scientific community as yet is working towards methods that can slow down the disease’s progression, but do not know how to stop the disease from occurring or how to stop it’s progression. According to ADI, there exist some drugs that can slow down progression is some patients with Alzheimer’s for periods between 6 and 18 months.
Indian Navy’s new aircraft carrier dry dock
Topic: GS -III: Security
A dry dock is essentially a berthing place in which the repair, refuelling and maintenance of a ship is carried out after dewatering the dock. It entails maintenance work like removing heavy machinery which cannot be done while the ship sails on water.
- While the naval dockyard in Mumbai had three existing British era dry docks, it had none that could accommodate an aircraft carrier vessel. At 281 m long, 45 m wide and almost 17 m deep, the dimensions of the new state-of-the-art dry dock were modified to accommodate the INS Vikramaditya, the Indian Navy’s only aircraft carrier.
Features of this new aircraft carrier dry dock
- Apart from its mammoth size, this dock has been described as an addition to the navy’s strategic assets because apart from berthing the aircraft carrier, the dry dock has three intermediate gates that can divide the dock across its length and accommodate two smaller vessels at the same time.
- Naval officers said that naval ships may no longer have to queue up at private dry docking facilities which can reduce the turnaround time that ships spend dry docking, giving the Indian Navy control over the maintenance time taken by each ship docked here.
- This also reduces the burden on the State exchequer since, estimates suggest, using private dry docking facilities could cost up to Rs 10 lakh a day depending on the ship and nature of works it required.
Challengesin the construction of the dock
- Constructed over a period of nine years at a cost of Rs 1000 crore, the modern dry dock was built 300 m into the sea with only its head on land. For building the 281 m long dock and the wharves on each of its sides, a coffer dam was built with 114 piles of steel and concrete to keep the water out while construction was carried out on the sea bed. The silt removed from the site was 2.23 lakh tonnes, enough to lay 90 football fields. The project required 8000 metric tonnes of steel and 5 metric tonnes of concrete, one-and-a-half times that used in Mumbai’s iconic Bandra-Worli sea link.
Tubewells in some Punjab villages drawing up muddy water
Topic: GS-III: Environment
Post recent floods some of villages in Jalandhar’s Shahkot and Kapurthala’sSultanpurLodhi have complained that their tubewells are pumping out contaminated and muddy groundwater.
- Over a dozen villages are complaining about the muddy, contaminated water in both Kapurthala and Jalandhar. Villages located close to ChittiBein, a highly polluted rivulet, are complaining about brackish water. But at the same time, villages like JaniaChahal, Mundi Chohlian, Nall, ChakWadala, which were also among worst hit villages and remained under water for a lot period, have not complained about.
Reasons behind this
- The Central Ground Water Board officials in Chandigarh office said water that has stagnated on the surface cannot go deep into earth in just 2-3 weeks and it takes years for water to go deep down at the depth level of tubewells as it first enters the first layer of earth and then it undergoes natural filtration which rids it of several pollutants.
- Experts blame faulty borewells, which have leakages or gaps as likely cause behind the problem that is still under observation. If 200 to 300 feet tubewells are pumping brackish water it is possible that contaminated water got inside directly. Direct injection of contaminated water can happen through faulty deep borewells.When a borewell is dug, its diameter is always little bigger than the diameter of the pipe that is to be inserted inside the bore because it helps an easy insertion. But after that the space between the borewell and the pipe must be filled with sand but normally it is left open in large number of cases. Whenever a tubewell gets submerged in any water that water will enter into bore through such leakages/open spaces and can get mixed with available aquifers inside the earth.
- econd reason could be that when entire area is flooded and tubewells are too get submerged, the flood water can enter inside the bore well through outlet.
- Due to heavy pressure of water through outlet, the filters installed inside borewell pipe can malfunction, thus letting dirty flood water directly enter the earth, which are totally opened beneath the earth. Such injection of flood water even through a single tubewellcan contaminate the entire aquifers of that village or even nearby areas up to few kms depending upon the spread of that aquifer.
- Third reason could be that due to collapsing of the borewell or some other leakage in the earth. Experts said that brackish water problem could be temporary or long term depending upon the quantity of such water that directly entered the earth through borewells.
Sagittarius A*: A black hole at the centre of the Milky Way
Topic: GS -III: Science and Technology
This year, Sagittarius A* has shown unusual activity, and the area around it has been much brighter than usual.
- A supermassive black hole sits 26,000 light years away from Earth, near the Galactic Centre, or the centre of the Milky Way. Called Sagittarius A*, it is one of the few black holes where we can witness the flow of matter nearby.
- Since the discovery of Sagittarius A* 24 years ago, it has been fairly calm. This year, however, Sagittarius A* has shown unusual activity, and the area around it has been much brighter than usual. In research published recently in The Astrophysical Journal Letters, scientists have sought to explain why this is happening.
Reasons for this brightness:
- It may be that the Sagittarius A* has become hungrier, and has been feeding on nearby matter at a markedly faster rate, which one researcher described as a “big feast”.
- A black hole does not emit light by itself, but the matter that it consumes can be a source of light. A large quantity of gas from the S0-2 star, which travelled close to the black hole last year, may now have reached the latter. Other possibilities of the heightened activity, the paper says, are that Sagittarius A* could be growing faster than usual in size, or that the current model that measures its level of brightness is inadequate and is in need of an update.
- The researchers noted three extraordinary occasions this year that marked the black hole’s unusual behaviour. On May 13, the area immediately outside Sagittarius A* was twice as bright as compared to any previously recorded instance.
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