(FREE) UPSC Current Affairs 2024 PDF

(Current Affairs) Science & Technology, Defence, Environment | June: 2017

Science & Technology, Defense, Environment

Central parts of Antarctica’s ice sheet have been stable for millions of years (Free Available)
Indian researchers has been able to achieve 100-fold reduction in TB bacterial load (Free Available)
Scientists have discovered a new moon orbiting the third largest dwarf planet (Free Available)
Commercial development of combustible ice closer to reality (Free Available)
NASA has dropped the idea of putting astronauts aboard the EM-1 (Free Available)
India’s notorious traffic pollution is no longer an urban malaise (Free Available)
Key to Microbial-resistant infections unravelled (Free Available)
The national surveillance programme for aquatic animal diseases (Free Available)
A new mission to Saturn’s moons Titan or Enceladus (Free Available)
Indian researchers have unravelled the mechanism to reverse drug resistance (Free Available)
Cartilage tissue generated using a 3D bioprinter (Only for Online Coaching Members)
GSAT-9 to make advanced Indian spacecraft far lighter (Only for Online Coaching Members)

Central parts of Antarctica’s ice sheet have been stable for millions of years

Central parts of Antarctica’s ice sheet have been stable for millions of years, even when conditions were considerably warmer than present, new research suggests.
The study of mountains in West Antarctica may help scientists improve their predictions of how the region might respond to continuing climate change. The findings could show how ice loss might contribute to sea level rise.
Although the discovery demonstrates the long-term stability of some parts of Antarctica’s ice sheet, scientists remain concerned that ice at its coastline is vulnerable to rising temperatures.
Researchers from the Universities of Edinburgh and Northumbria in the U.K. studied rocks on slopes of the Ellsworth Mountains, whose peaks protrude through the ice sheet.
By mapping and analysing surface rocks, researchers calculated that the mountains have been shaped by an ice sheet over a million-year period, beginning in a climate some 20 degrees Celsius warmer than at present.

Commercial development of combustible ice closer to reality

Commercial development of the globe’s huge reserves of a frozen fossil fuel known as “combustible ice” has moved closer to reality after Japan and China successfully extracted the material from the sea floor off their coastlines.
But experts said that large-scale production remains many years away and if not done properly could flood the atmosphere with climate-changing greenhouse gases.
Combustible ice is a frozen mixture of water and concentrated natural gas. Technically known as methane hydrate, it can be lit on fire in its frozen state and is believed to comprise one of the world’s most abundant fossil fuels.
For Japan, methane hydrate offers the chance to reduce its heavy reliance of imported fuels if it can tap into reserves off its coastline.
In China, it could serve as a cleaner substitute for coal-burning power plants and steel factories that have polluted much of the country with lung-damaging smog.
Methane hydrate has been found beneath seafloors and buried inside Arctic permafrost and beneath Antarctic ice.
Estimates of worldwide reserves range from 280 trillion cubic metres up to 2,800 trillion cubic metres,, according to the U.S. Energy Information Administration.
That means methane hydrate reserves could meet global gas demands for 80 to 800 years at current consumption rates.
Yet efforts to successfully extract the fuel at a profit have eluded private and state-owned energy companies for decades.
There are also environmental concerns. If methane hydrate leaks during the extraction process, it can increase greenhouse gas emissions. The fuel also could displace renewables such as solar and wind power.

NASA has dropped the idea of putting astronauts aboard the EM-1

NASA has dropped the idea of putting astronauts aboard the first integrated flight of the Space Launch System rocket and Orion spacecraft - Exploration Mission-1 (EM-1).
This is the first in a broad series of exploration missions that plans to take humans to deep space, and eventually to Mars.
NASA’s original plan was to launch the test flight without crew, but in February, reportedly at the request of the Donald Trump administration, NASA began an effort looking at the feasibility of putting crew aboard EM-1.
However, engineers will apply insights gained from the effort to the first flight test and the integrated systems to strengthen the long-term push to extend human presence deeper into the solar system.
NASA determined it is technically capable of launching crew on EM-1, but after evaluating cost, risk and technical factors in a project of this magnitude, it would be difficult to accommodate changes needed to add crew at this point in mission planning.
The effort confirmed that the baseline plan to fly EM-1 without crew is still the best approach to enable humans to move sustainably beyond a low-Earth orbit.

Key to Microbial-resistant infections unravelled

Bacteria have specific surface proteins which are used for binding to host cells.
Scientists at the the University of Madras, have succeeded in characterising such surface proteins of some pathogenic bacteria including Streptococcus agalactiae and Enterococcus faecium. Infection by both of these bacteria can have deadly effects on humans.
The studies by the group have also shown that the structure of the surface protein of E. faecium has a special fold which sets it apart from all known categories of protein structure known so far.
In order to colonise a host cell, bacteria need to attach themselves to the surface of the host using certain surface proteins.
The surface protein on the bacterial cell functions as a “key” to the protein on the host cell membrane which acts as a “lock” — that is to say, the former fits snugly into the latter.
This linking up by means of the lock and key mechanism is crucial for the infection to proceed. Therefore, drugs may be developed to hinder this process of formation of the link.
The crucial thing to know in this case is the structure of the surface proteins of the bacteria, which is what the group works at.
The strain S. agalacticae is a Gram positive bacterium that causes life-threatening diseases such as bacterial sepsis and meningitis in newborn babies and several diseases including pneumonia in non-pregnant adults.
But the more exciting discovery is the structure of the SgrA protein of E. faecium. This antibiotic-resistant bacterium causes urinary tract infection and surgical site infections.
Catheter-induced infections could also be caused by this strain as its surface protein SgrA is known to be able to bind to abiotic surfaces, such as polystyrene.
The process involved first cloning and purifying the protein and crystallising it. The structure was discovered by X-ray diffraction.
To their surprise the team discovered that the structure of SgrA contained a fold that did not fit into the known catalogues of protein structures in the Protein Structure Database.
The discovery can be used by drug developers to target these unique surface adhesins and thereby tackle, among others, catheter-related infections.

The national surveillance programme for aquatic animal diseases

The national surveillance programme for aquatic animal diseases in India, one of the largest fish disease surveillance programme implemented in the country, is all set to begin a new phase.
A road map proposed for taking the surveillance programme to the next level includes developing disease-free zones and targeted active surveillance for fish pathogens in India.
The programme is led by the ICAR-National Bureau of Fish Genetic Resources (ICAR-NBFGR), Lucknow; J. K. Jena is the national coordinator. The programme is currently being implemented in 16 States and three Union Territories.
There has been significant improvement in the reporting of aquatic animal diseases, the researchers say. As a result, more new pathogens are being detected from the Indian waters.
The mass mortality of goldfish in West Bengal in 2014 was confirmed to have been caused by cyprinid herpesvirus-2.
The presence of another important pathogen, Enterocytozoon hepatopenaei, was reported for the first time from the shrimp species Litopenaeus vannamei and infection caused by Perkinsus olseni were reported in Asian Green Mussel, a new host.
The focus of the programme is on strengthening the “passive surveillance system in the country,” and to improve disease reporting by farmers and state fisheries officers, explained Kuldeep K. Lal, Director of NBFGR.
Around 1,100 farms in as many as 110 districts across the country are being monitored regularly.

Indian researchers have unravelled the mechanism to reverse drug resistance

Indian researchers have unravelled the mechanism by which hydrogen sulphide (H2S) gas produced by bacteria protects them from antibiotics and plays a key role in helping bacteria develop drug resistance.
And by blocking/disabling the enzyme that triggers the biosynthesis of hydrogen sulphide in bacteria, the researchers from Bengaluru’s Indian Institute of Science (IISc) and IISER Pune, have been able to reverse antibiotic resistance in E. coli bacteria.
E. coli bacteria were isolated from patients suffering from urinary tract infection. The results were published in the journal Chemical Science.
Antibiotics kill by increasing the levels of reactive oxygen species (oxidative stress) inside bacterial cells. So any mechanism that detoxifies or counters reactive oxygen species generated by antibiotics will reduce the efficacy of antibiotics.
The researchers carried out simple experiments to establish this. They first ascertained that regardless of the mode of action of antibiotics, the drugs uniformly induce reactive oxygen species formation inside E. coli bacteria.
To reconfirm hydrogen sulphide’s role in countering reactive oxygen species, the team took multidrug-resistant, pathogenic strains of E. coli from patients suffering from urinary tract infection and measured the hydrogen sulphide levels in these strains.
The researchers identified that E. coli has two modes of respiration involving two different enzymes. The hydrogen sulphide gas produced shuts down E. coli’s aerobic respiration by targeting the main enzyme (cytochrome bo oxidase (CyoA)) responsible for it.
E. coli then switches over to an alternative mode of respiration by relying on a different enzyme — cytochrome bd oxidase (Cydb). Besides enabling respiration, the Cydb enzyme detoxifies the reactive oxygen species produced by antibiotics and blunts the action of antibiotics.
The link between hydrogen sulphide and Cydb enzyme in the emergence of drug resistance is another key finding of the study.

GSAT-9 to make advanced Indian spacecraft far lighter

GSAT-9 or the South Asia Satellite, will carry a new feature that will eventually make advanced Indian spacecraft far lighter. It will even lower the cost of launches tangibly in the near future.
The 2,195-kg GSAT-9, due to take off on a GSLV rocket on May 5, carries an electric propulsion or EP system. The hardware is a first on an Indian spacecraft.
The satellite will be flying with around 80 kg of chemical fuel - or just about 25% of what it would have otherwise carried.Managing it for more than a decade in orbit will become cost efficient.
In the long run, with the crucial weight factor coming down later even for sophisticated satellites, ISRO can launch them on its upcoming heavy rockets instead of sending them to space on costly foreign boosters.