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Subject: Science and Technology

  • What is the ‘Sonic Boom’ that rattled Bengaluru city?

    The ‘loud sound’ heard in Bengaluru a few days back, which puzzled lakhs of city dwellers, was revealed to have emanated from an IAF test flight involving a supersonic profile. The sonic boom was probably heard while the IAF aircraft was decelerating from supersonic to subsonic speed between 36,000 and 40000 feet altitude.

    Note:

    We often get to hear about updates in  India’s missile programme. UPSC may ask a basic physics question asking fundamental differences between various Mach number and its differences.

    What is a ‘sonic boom’?

    • Sound travels in the form of waves which are emitted outwards from its source.
    • In air, the speed of these waves depends on a number of factors, such as the temperature of the air and altitude.
    • When an aircraft travels at supersonic speed – meaning faster than sound (>1225 kmph at sea level) – the field of sound waves moves to the back of the craft.
    • A stationary observer thus hears no sound when a supersonic flight approaches since the sound waves are at the rear of the latter.
    • At such speeds, both newly created as well as old waves, are forced into a region at the aircraft’s rear called a ‘Mach cone’, which extends from the craft and intercepts the Earth in a hyperbola-shaped curve, and leaves a trail called the ‘boom carpet’.
    • The loud sound that is heard on the Earth when this happens is called a ‘sonic boom’ (resembles bomb-blast sound).

    Impacts

    • When such aircraft fly at a low altitude, the sonic boom can become intense enough to cause the glass to crack or cause health hazards.
    • Overland supersonic flights have thus been banned in many countries.

    Supersonic flights

    • In 1947, the American military pilot Chuck Yeager became the first to breach the sound barrier, flying the Bell X-1 aircraft at 1127 kmph.
    • Since then, many supersonic flights have followed, with advanced designs allowing speeds of over Mach 3, or three times the speed of sound.
    • According to the IAF website, India’s fastest jets include the Sukhoi SU-30 MKI (Mach 2.35) and the Mirage-2000 (Mach 2.3).

    Back2Basics: Traverse of sound

    • From a stationary source, such as a television set, sound waves travel outwards in concentric spheres of growing radii.
    • When the source of sound is moving – e.g, a truck– the successive waves in front of the truck get closer together, and the ones behind it spread out.
    • This is also the cause of the Doppler effect– in which bunched waves at the front appear at a higher frequency to a stationary observer, and spread out waves that are behind are observed at a lower frequency.
    • As long as the source of the sound keeps moving slower than the speed of sound itself, this source– say a truck or a plane – remains nested within the sound waves that are travelling in all directions.

    Mach number

    • The ratio of the speed of the aircraft to the speed of sound in the gas determines the magnitude of many of the compressibility effects.
    • Because of the importance of this speed ratio, aerodynamicists have designated it with a special parameter called the Mach number in honour of Ernst Mach, a late 19th-century physicist who studied gas dynamics.
    • Subsonic conditions occur for Mach numbers less than one, M < 1.
    • As the speed of the object approaches the speed of sound, the flight Mach number is nearly equal to one, M = 1, and the flow is said to be transonic.
    • Supersonic conditions occur for Mach numbers greater than one, 1 < M < 3.
    • For speeds greater than five times the speed of sound, M > 5, the flow is said to be hypersonic.
    • The Space Shuttle re-enters the atmosphere at high hypersonic speeds, M ~ 25. Under these conditions, the heated air becomes ionized plasma of gas and the spacecraft must be insulated from the high temperatures.

  • [pib] Certification of ‘Quantum Entanglement’

    Indian scientists have developed a novel protocol to find out whether a pair of electrons are in an entangled state so that they can be safely used as resources for facilitating quantum information processing tasks.

    Trending in news this year is the Quantum Technology, (As it used to be until last year were- the Internet of Things (IoT) CSP 2019, Artificial Intelligence (AI) etc.)

    Must read all this news in a loop:

    National Mission on QC

    Quantum Coin

    Quantum Supremacy

    What is Quantum Entanglement (QE)?

    • QE is the name given to a special connection between pairs or groups of quantum systems, or any objects described by quantum mechanics.
    • It is one of the biggest parts of quantum mechanics that makes it hard to understand in terms of the everyday world.
    • When we look at particles, we usually say that each particle has its own quantum state. Sometimes, two particles can act on one another and become an entangled system.
    • When a pair or group of particles can only be described by the quantum state for the system, and not by individual quantum states, we say the particles are “entangled”.

    Going bit technical here-

    • It is the physical phenomenon that occurs when a pair or group of particles is generated; interact, in a way such that the quantum state of each particle of the pair or group cannot be described independently of the state of the others.
    • Entangled states are key resources to facilitate many quantum information processing tasks and quantum cryptographic protocols.

    Why decode the Entanglement?

    • Entanglement is fragile and is easily lost during the transit of photons through the environment.
    • Hence it is extremely important to know whether a pair of photons are entangled, in order to use them as a resource.
    • Verification of entanglement requires the use of measurement devices, but such devices may be hacked or compromised.

    How to secure QE?

    • Device-independent self-testing (DIST) is a method that can be used in order to overcome such a possibility.
    • This method enables the verification of entanglement in an unknown quantum state of two photons without having direct access to the state, or complete trust in the measurement devices.
    • The theory relies on the application of the quantum uncertainty principle while implementing full device independence is a difficult task.

    Back2Basics: Quantum Mechanics

    • Quantum mechanics (QM) is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.
    • It is the body of scientific laws that describe the wacky behaviour of photons, electrons and the other particles that make up the universe.

  • [pib] Alternative Dwarfing Genes in Wheat

    Scientists at Pune based Agharkar Research Institute (ARI) an autonomous institute of the Department of Science and Technology has mapped two dwarfing genes Rht14 and Rht18 in wheat that can reduce stubble volume.

    Note: One may wonder why the name of research institution has not been skipped here!

    Q. With reference to the Genetically Modified mustard (GM mustard) developed in India, consider the following statements:

    1. GM mustard has the genes of a soil bacterium that give the plant the property of pest-resistance to a wide variety of pests.
    2. GM mustard has the genes that allow the plant cross-pollination and hybridization.
    3. GM mustard has been developed jointly by the IARI and Punjab Agricultural University.

    Which of the statements given above is/are correct? (CSP 2018)

    (a) 1 and 3 only

    (b) 2 only

    (c) 2 and 3 only

    (d) 1, 2 and 3

    Rht14 and Rht18

    • The researchers have mapped the dwarfing genes on chromosome 6A in durum wheat, and DNA-based markers were developed for a better selection of these genes in wheat breeding lines.
    • These genes are associated with better seedling vigour and longer coleoptiles (sheath protecting the young shoot tip).
    • These DNA based markers are being used at ARI for marker-assisted transfer of these genes in Indian wheat varieties, so as to make them suitable for sowing under rice stubble-retained conditions and dry environments.
    • Wheat lines with these alternative dwarfing genes, apart from reducing crop residue burning, can allow deeper sowing of wheat seeds to avail advantage of residual moisture in the soil under dry environments.
    • Wheat lines with these alternative dwarfing genes, apart from reducing crop residue burning, can allow deeper sowing of wheat seeds to avail advantage of residual moisture in the soil under dry environments.

    Significance

    • In India, close to twenty-three million tonnes of leftover rice residues are annually burnt by farmers to get rid of the straw and prepare their fields for sowing wheat, which is the next crop, resulting in air pollution.
    • Burning of leftover rice crop residue has serious implications for the environment, soil, and human health.
    • Therefore, there is a need to include alternative dwarfing genes in wheat improvement programs.
    • The dwarfing genes Rht14 and Rht18 in wheat conferred a plant height reduction comparable to the Rht1 alleles while retaining early vigour in wheat seedlings, but do not affect coleoptile length and seedling shoot length.
    • These can, therefore, be utilized as an alternative dwarfing gene to Rht1 for deep sowing conditions or in fields with retained stubble.
    • The improved wheat lines which are being developed at ARI will help reducing stubble burning incidences under the rice-wheat cropping system.
    • These lines will also allow deeper sowing of wheat seeds to avail advantage of residual moisture in the soil, therefore, saving valuable water resources and reduce the cost of cultivation to farmers.

  • ‘Agappe Chitra Magna’ kit for COVID diagnosis

    Agappe Chitra Magna, a magnetic nanoparticles-based RNA extraction kit has been commercially launched.

    The peculiarity of the name ‘Agappe Chitra Magna’ creates a possibility of a prelims question. One may confuse it with any sort of Artform.

    Agappe Chitra Magna (ACM) Kit

    • The ACM kit is developed by the Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST) and manufactured by Kochi-based Agappe Diagnostics Ltd.,
    • It uses innovative technology for isolating RNA using magnetic nanoparticles to capture the RNA from the patient sample.
    • The magnetic nanoparticles beads bind to the viral RNA and, when exposed to a magnetic field, give a highly purified and concentrated RNA.
    • As the sensitivity of the detection method is dependent on getting an adequate quantity of viral RNA, this innovation enhances the chances of identifying positive cases.
    • The commercial launch of the kit is a major step to make India self-reliant in detecting COVID-19 and can help increase the rate of testing and bring down its costs, a crucial step for combating the pandemic.

    Significance of the kit

    • The commercial launch of the kit is a major step to make India self-reliant in detecting COVID-19 and can help increase the rate of testing and bring down its costs, a crucial step for combating the pandemic.
    • The RNA isolation kit will reduce the dependence on imported kits and make COVID testing more cost-effective.

  • What is Solar Minimum?

    The sun is said to have gone into a state called the ‘solar minimum’ and is about to enter the deepest period of ‘sunshine recession’ as sunspots are virtually not visibly at all.

    Practice question for Mains:

    Q. What are Solar minima and maxima? Discuss its impact on space weather and the Earth.

    What is a solar minimum and why is it happening now?

    • Sun has a cycle that lasts on average 11 years, and right now we are at the peak of that cycle.
    • Every 11 years or so, sunspots fade away, bringing a period of relative calm.
    • This is called the solar minimum. And it’s a regular part of the sunspot cycle.
    • While intense activity such as sunspots and solar flares subside during solar minimum, that doesn’t mean the sun becomes dull. Solar activity simply changes form.

    What about Solar Maximum?

    • Solar minima and maxima are the two extremes of the Sun’s 11-year and 400-year activity cycle.
    • At a maximum, the Sun is peppered with sunspots, solar flares erupt, and the Sun hurls billion-ton clouds of electrified gas into space.
    • Sky watchers may see more auroras, and space agencies must monitor radiation storms for astronaut protection.
    • Power outages, satellite malfunctions, communication disruptions, and GPS receiver malfunctions are just a few of the things that can happen during a solar maximum.

    What are its effects on Earth?

    a) On space weather

    • The Solar wind from coronal holes will temporarily create disturbances in the Earth’s magnetosphere, called geomagnetic storms, auroras, and disruptions to communications and navigation systems.
    • The space weather during solar minimum will also affect Earth’s upper atmosphere on satellites in low Earth orbit changes.
    • This means that the Earth’s upper atmosphere will cool down which is generally heated and puffed up by ultraviolet radiation from the sun.
    • However, the heat at the upper atmosphere of our planet helps Earth to drag debris and keep the low Earth orbit clear of manmade space junk.
    • Apart from this, the solar minimum will change the space weather significantly which will lead to an increase in the number of galactic cosmic rays that reach Earth’s upper atmosphere.
    • These Galactic cosmic rays are high energy particles which are a result of distant supernova explosions and other violent events in the galaxy.

    b) On astronauts

    • According to NASA the sun’s magnetic field weakens and provides less shielding from these cosmic rays during a solar minimum which will directly increase the threat to astronauts travelling through space.
    • This may cause health risks to astronauts travelling through space as the sun’s magnetic field weakens and provides less shielding from these cosmic rays.

  • [pib] Iron-Manganese based Biodegradable Alloy

    Indian scientists have jointly developed new generation Iron-Manganese based alloys for biodegradable metal implants for use in humans.

    Do you remember the Johnson and Johnson’s faulty hip implants case?? The alloy mentioned in the newscard can prove to be a gamechanger in the field of medical implants.

    Iron-Manganese based Biodegradable Alloy

    • Biodegradable materials (Fe, Mg, Zn, and polymer) can participate in the healing process and then degrade gradually by maintaining mechanical integrity without leaving any implant residues in the human body.
    • They are better alternatives to currently used metallic implants which remain permanently in the human body and can cause long-term side effects like systemic toxicity, chronic inflammation, and thrombosis.
    • The ARCI team employed both conventional melting and powder metallurgy techniques in the manufacturing of the new Fe-Mn based biodegradable alloys.
    • The alloy Fe-Mn (having Mn composition of more than 29% by weight) is a promising biodegradable metallic implant which exhibits a single austenitic phase (a non-magnetic form of iron) with MRI compatibility.

    Easy degradation

    • The alloy also showed a degradation rate in the range of 0.14-0.026 mm per year in the simulated body fluid.
    • It means that the Fe-Mn alloy exhibits mechanical integrity for 3-6 months and completely, disappears from the body in 12-24 months.
    • During the degradation process, calcium phosphate deposits on the implant due to local alkalization and saturation of calcium and phosphate, allow cells to adhere onto the surface to form tissues.

    Benefits

    • The Fe-Mn alloy produced at ARCI exhibited 99% density with impressive mechanical properties and behaved as a nonmagnetic material even under a strong magnetic field.
    • These properties are comparable to presently used permanent Titanium (Ti) and stainless-steel metallic implants (which is very costly).

  • International Day of Light and its significance

    The UN marks the International Day of Light (IDL) — an annual initiative held globally to raise awareness on the critical role played by light-based technologies in everyday life.

    The IDL as mentioned in the news creates no scope for a possible prelim question, but the purpose behind its celebration does.  i.e. LASER technology. LIDAR is the latest development in the LASER technology. UPSC may puzzle you here by asking the working principle of LIDAR.

    International Day of Light (IDL)

    • The IDL is administered from the International Basic Science Programme (IBSP) of UNESCO, and its Secretariat is located at the Abdus Salam International Centre of Theoretical Physics (ICTP) at Trieste, Italy.
    • The IDL highlights the contribution of such technologies in various avenues such as science, technology, art, and culture, thus helping achieve the UNESCO goals of education, equality, and peace.
    • The day selected, May 16, marks the anniversary of the first successful operation of the LASER in 1960 by physicist and engineer Theodore Maiman.
    • The LASER is a perfect example of how a scientific discovery can yield revolutionary benefits to society in communications, healthcare and many other fields.

    Why is the IDL celebrated?

    • In 2015, to raise global awareness of the achievements of light science and its applications, the UN observed the International Year of Light and Light-based Technologies 2015 (IYL 2015).
    • The event helped establish links and collaborations between decision-makers, industry leaders, scientists, artists, social businesses, NGOs, and the public at large.
    • Following the success of IYL 2015, Ghana, Mexico, New Zealand and Russia placed a resolution before the UNESCO Executive Board supporting the idea of an International Day of Light.
    • It was adopted on September 19, 2016, at the Board’s 200th session at the UNESCO HQ in Paris, France.
    • The Board decision was endorsed by the UNESCO General Conference at its 39th session on November 7, 2017, and the first IDL was held on May 16, 2018.

    Back2Basics: LASER

    • A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation.
    • It is an acronym for “light amplification by the stimulated emission of radiation.
    • The laser stimulates atoms or molecules to emit light at particular wavelengths and amplifies that light, typically producing a very narrow beam of radiation.
    • The emission generally covers an extremely limited range of visible, infrared, or ultraviolet wavelengths.
    • Many different types of lasers have been developed, with highly varied characteristics.
    • A laser is widely used in industrial cutting, surgical removal of tissues etc.
    • LIDAR is the most famous application of LASERs.

    LiDAR (Light Detection And Ranging)

    • It is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth.
    • It bounces pulsed laser light off the ground, revealing contours hidden by dense foliage.
    • These light pulses—combined with other data recorded by the airborne system— generate precise, three-dimensional information about the shape of the Earth and its surface characteristics.
    • LIDAR systems allow scientists and mapping professionals to examine both natural and manmade environments with accuracy, precision, and flexibility.
    • A LIDAR instrument principally consists of a laser, a scanner, and a specialized GPS receiver.
    • Airplanes and helicopters are the most commonly used platforms for acquiring LIDAR data over broad areas.

  • Species in news: Quinine Nongladew

    Quinine, the most primitive antimalarial avatar of Hydroxychloroquine (HCQ), has made a village in Meghalaya latch on to its past for a curative future.

    Relate Quinine Nongladew with the following question. Such peculiar names are very important.

    Q. Recently, there was a growing awareness in our country about the importance of Himalayan nettle (Girardinia diversifolia) because it is found to be a sustainable source of (CSP 2019)

    (a) anti-malarial drug

    (b) bio-diesel

    (c) pulp for paper industry

    (d) textile fibre

    Quinine Nongladew

    • The herb Quinine Nongladew is the alkaloid quinine extracted from the bark of cinchona, a plant belonging to the Rubiaceae family and classified as either a large shrub or a small tree
    • The tree is named after a village about 70 km south of Guwahati, on the highway to Meghalaya capital Shillong.
    • The cinchona nursery was raised in the 19th century, probably around 1874, when Shillong became the British administrative headquarters for Assam Province.
    • Large swathes of Meghalaya used to be, and still are, malaria-prone.
    • The British had the foresight to start the plantation to combat malaria and other diseases caused by mosquitoes.

    Back2Basics: Hydroxychloroquine (HCQ)

    • HCQ is an oral tablet used as an anti-malarial drug. It is used to treat malaria, lupus erythematosus, and rheumatoid arthritis.
    • It may be used as part of a combination therapy where it is taken with other drugs.

  • What is Palliative Care?

    The newscard talks about palliative healthcare which may help when the world is reeling under this most unexpected and unprecedented pandemic, COVID-19.

    Palliative Care is a promising approach to counter the psychosocial impacts of the COVID-19 outbreak. We can use this as an example to quantify the measures required to improve mental healthcare infrastructure in India.

    Social sufferings caused by the pandemic

    • COVID-19, because of its unique nature and magnitude has brought in its wake, not only physical illness but more of emotional and social suffering.
    • These include- fear, anxiety, uncertainty, loss of loved ones and social distress such as losing jobs and income, inability to move freely to work and other places, frustrations, staying long hours at home and other hardships, all leading to psychological disturbances for many.

    What is Palliative Care?

    • The literal meaning of the word ‘palliate’ is ‘to alleviate pain — physical and emotional’, meaning, relief of suffering. ‘Suffering’ literally means ‘the state of undergoing pain, distress, or hardship’.
    • It is an approach that improves the quality of life of patients and their families facing the problem associated with a life-threatening illness.
    • It involves prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain and other problems, physical, psychosocial and spiritual.
    • It is part and parcel of treatment for any patient for any disease at any stage, for any age. It is simply a ‘whole person’ approach to improving health in any patient.

    A promising remedy

    • ‘Palliative Medicine’ is a medical speciality, which involves the treatment of pain, breathing difficulty and other distressing physical symptoms caused by chronic and life-limiting diseases.
    • It also addresses the psychological issues of both patient and family, with the sole aim of improving the quality of life. It is most beneficial when started early in the disease trajectory.
    • It is also a form of supportive care, giving that extra layer of support a patient needs, to alleviate suffering, alongside disease treatment even in acute illness.
    • In the present scenario, in addition to what physicians are toiling with to cure patients, and the government and health care policies and strategies, palliative care can play a supportive role.

    Supportive role

    • Distressing physical symptoms like pain, breathing difficulty, restlessness (delirium) and others can be well relieved or palliated with medicines in consultation with the specialists.
    • Similarly, skilled counselling is an integral part of the palliative approach.
    • It helps address the psychological, social and spiritual issues, which both patient and family are experiencing in the present scenario.
    • There is a way of responding to their fears, anxieties and to questions. They rarely need antidepressants when we acknowledge their emotions as normal.

    Conclusion

    • Active listening is by far the most important part of counselling.
    • This care can be availed of from psychologists, specialists in palliative medicine, as well as those from medical organisations who have the expertise and willingness to render their services.
    • Hence, Palliative care is the reinstatement of the humane aspects of medical care and is complementary to all medical specialities, a common thread running through the total care of all patients.

  • What is ‘Direct Seeding of Rice’ (DSR)?

    Farmers are now being encouraged to adopt ‘direct seeding of rice’ (DSR) in place of conventional transplanting due to lack of labourers, who are stranded due to lockdown.

    Recall the classification of cropping seasons on India based on onset and retreat of Monsoon.

    The kharif crops include rice, maize, sorghum, pearl millet/bajra, finger millet/ragi (cereals), arhar (pulses), soyabean, groundnut (oilseeds), cotton etc. The rabi crops include wheat, barley, oats (cereals), chickpea/gram (pulses), linseed, mustard (oilseeds) etc.  Kindly make a note of this.

    What is ‘Direct Seeding of Rice’ (DSR)?

    • In transplanting, farmers prepare nurseries where the paddy seeds are first sown and raised into young plants.
    • These seedlings are then uprooted and replanted 25-35 days later in the main field.
    • Paddy seedlings are transplanted on fields that are “puddled” or tilled in standing water using tractor-drawn disc harrows.
    • In DSR, there is no nursery preparation or transplantation. The seeds are instead directly drilled into the field by a tractor-powered machine.

    How is the question of herbicides addressed in DSR?

    • Paddy being very much water-intensive is compromised by weeds that compete for nutrition, sunlight and water.
    • Water prevents the growth of weeds by denying them oxygen in the submerged stage, whereas the soft ‘aerenchyma tissues’ in paddy plants allow air to penetrate through their roots.
    • Water, thus, acts as a herbicide for paddy. The threat from weeds recedes once tillering is over; so does the need to flood the fields.
    • In DSR, water is replaced by real chemical herbicides. Farmers have to only level their land and give one pre-sowing irrigation or rauni.
    • Once the field has good soil moisture, they need to do two rounds of ploughing and planking (smoothening of soil surface), which is followed by the sowing of the seeds and spraying of herbicides.

    What are these herbicides?

    • There are two kinds. The first is called pre-emergent, i.e. applied before germination. In this case, the pre-emergent herbicide used is Pendimethalin.
    • The second set of herbicides is post-emergent, sprayed 20-25 days after sowing, depending upon the type of weeds appearing.
    • They include Bispyribac-sodium (Rs 600-700 at 100 ml/acre) and Fenoxaprop-p-ethyl (Rs 700-800 at 400 ml/acre).

    What is the main advantage of DSR?

    • The most obvious one is water savings. The first irrigation (apart from the pre-sowing rauni) under DSR is necessary only 21 days after sowing.
    • This is unlike in transplanted paddy, where watering has to be done practically daily to ensure submerged/flooded conditions in the first three weeks.
    • The second savings, relevant in the present context, is that of labour. About three labourers are required to transplant one acre of paddy at almost Rs 2,400 per acre.
    • As against this, the cost of herbicides under DSR will not exceed Rs 2,000 per acre.

    Limitations of DSR

    • The main issue is the availability of herbicides.
    • The seed requirement for DSR is also higher, at 8-10 kg/acre, compared to 4-5 kg in transplanting.
    • Further, laser land levelling, which costs Rs 1,000/acre, is compulsory in DSR. This is not so in transplanting.
    • The yields are as good as from normal transplanting, but one need to sow by the first fortnight of June. The plants have to come out properly before the monsoon rains arrive.
    • There is no such problem in transplanting, where the saplings have already been raised in the nursery.