Daily Quiz #24 UPSC Prelims Marathon – October 31, 2019

Explanation: Delhi-based researchers have found that inhibiting lipid synthesis inside stem cells that produce bone cells (mesenchymal stem cells) can help in killing TB bacteria that are found inside the stem cells in a dormant state and safely shielded from the host immune system and TB drugs. While TB bacteria inside the macrophages actively divide, microbes inside stem cells lie dormant and also make the stem cells less likely to replicate thus surviving for an extended period of time. Ex vivo studies with human stem cells and work on mice showed that the two cells are programmed very differently to support active and dormant TB bacteria infection. A team led by Gobardhan Das from the Special Centre for Molecular Medicine at the Jawaharlal Nehru University (JNU) found that TB bacteria are free in the intracellular fluid (cytosol) of the mesenchymal stem cells while they are surrounded by the macrophage cell membrane on being engulfed. This allows the bacteria to promote rapid synthesis of lipids inside the stem cells and hide within the lipid droplets so created.

Explanation: Researchers from IIT Bombay have discovered special properties in a class of materials called “semi-Dirac metals” that have been recently talked about in the scientific literature. Examples of semi-Dirac metals are systems such as TiO2/V2O3 nanostructures. Through calculations, the researchers have shown that such materials would be transparent to light of a given frequency and polarisation when it is incident along a particular direction. The material would be opaque to the same light when it falls on it from a different direction. There are many known applications for transparent conducting films – the common example being touch screens used in mobiles.

Explanation: India will launch Aditya-L1, its first mission to study the sun, in 2020. The Aditya-1 mission was conceived as a 400kg class satellite carrying one payload, the Visible Emission Line Coronagraph (VELC) and was planned to launch in a 800 km low earth orbit. A Satellite placed in the halo orbit around the Lagrangian point 1 (L1) of the Sun-Earth system has the major advantage of continuously viewing the Sun without any occultation/ eclipses. Therefore, the Aditya-1 mission has now been revised to “Aditya-L1 mission” and will be inserted in a halo orbit around the L1, which is 1.5 million km from the Earth. The satellite carries additional six payloads with enhanced science scope and objectives.

Explanation: NASA has selected a new mission that will help scientists understand and, ultimately, forecast the vast space weather system around our planet. Space weather is important because it can have profound impacts – affecting technology and astronauts in space, disrupting radio communications and, at its most severe, overwhelming power grids. The new experiment will, for the first time, obtain global observations of an important driver of space weather in a dynamic region of Earth’s upper atmosphere that can cause interference with radio and GPS communications. The Atmospheric Waves Experiment (AWE) mission will cost $42 million and is planned to launch in August 2022, attached to the exterior of the Earth-orbiting International Space Station. From its space station perch, AWE will focus on colorful bands of light in Earth’s atmosphere, called airglow, to determine what combination of forces drive space weather in the upper atmosphere.

Explanation: The Mission, launched in 2015, envisages empowering our national academic and R&D institutions spread over the country by installing a vast supercomputing grid comprising of more than 70 high performance computing facilities. The mission would be implemented jointly by Department of Science and Technology (DST) and Department of Electronics and Information Technology (DeitY) through two organizations the Centre for Development of Advanced Computing (C-DAC) and the Indian Institute of Science (IISc), Bangalore. The Mission envisages empowering our national academic and R&D institutions spread over the country by installing a vast supercomputing grid comprising of more than 70 high-performance computing facilities.