Seismology of the Sun : Inference of Thermal, Dynamic and Magnetic Field Structures of the Interior

Recent overwhelming evidences show that the sun strongly influences the Earth's climate and environment. Moreover existence of life on this Earth mainly depends upon the sun's energy. Hence, understanding of physics of the sun, especially the thermal, dynamic and magnetic field structures of its interior, is very important. Recently, from the ground and space based observations, it is discovered that sun oscillates near 5 min periodicity in millions of modes. This discovery heralded a new era in solar physics and a separate branch called helioseismology or seismology of the sun has started. Before the advent of helioseismology, sun's thermal structure of the interior was understood from the evolutionary solution of stellar structure equations that mimicked the present age, mass and radius of the sun. Whereas solution of MHD equations yielded internal dynamics and magnetic field structure of the sun's interior. In this presentation, I review the thermal, dynamic and magnetic field structures of the sun's interior as inferred by the helioseismology.Comment: To be published in the proceedings of the meeting "3rd International Conference on Current Developments in Atomic, Molecular, Optical and Nano Physics with Applications", December 14-16, 2011, New Delhi, Indi

A genomic appraisal of invasive Salmonella Typhimurium and associated antibiotic resistance in sub-Saharan Africa

Invasive non-typhoidal Salmonella (iNTS) disease manifesting as bloodstream infection with high mortality is responsible for a huge public health burden in sub-Saharan Africa. Salmonella enterica serovar Typhimurium (S. Typhimurium) is the main cause of iNTS disease in Africa. By analysing whole genome sequence data from 1303 S. Typhimurium isolates originating from 19 African countries and isolated between 1979 and 2017, here we show a thorough scaled appraisal of the population structure of iNTS disease caused by S. Typhimurium across many of Africa’s most impacted countries. At least six invasive S. Typhimurium clades have already emerged, with ST313 lineage 2 or ST313-L2 driving the current pandemic. ST313-L2 likely emerged in the Democratic Republic of Congo around 1980 and further spread in the mid 1990s. We observed plasmid-borne as well as chromosomally encoded fluoroquinolone resistance underlying emergences of extensive-drug and pan-drug resistance. Our work provides an overview of the evolution of invasive S. Typhimurium disease, and can be exploited to target control measures

ELLIPSOMETRIC MEASUREMENT OF THE SPECIFIC VOLUMES OF PHOSPHOLIPIDS AND PROTEINS AT SOLID-WATER INTERFACES

Les volumes spécifiques v de phospholipides déposés sur des plaques de chrome, sont déterminés dans un tampon de soluté physiologique. Les changements de v dus à l'hydratation et à la variation de température sont aussi mesurés, ainsi que le volume spécifique de la prothrombine adsorbée sur des multicouches de phospholipides. Quelques complications éventuelles de cette méthode sont discutées.The specific volumes v of phospholipids deposited on chromium slides, are measured in buffered physiological saline. Changes in v due to hydration and due to variation of temperature are also measured, as well as the specific volume of prothrombin adsorbed to phospholipid multilayers. Some possible complications of the method are discussed

ELLIPSOMETRIC MEASUREMENT OF THE ASSOCIATION OF PROTHROMBIN WITH PHOSPHOLIPID MONOLAYERS

Des couches monomoléculaires formées d'un mélange de phosphatidylserine et phosphatidylcholine sont déposées sur des plaques de chrome. L'association de prothrombine avec ces phospholipides est mesurée dans un tampon de soluté physiologique. Les résultats indiquent l'existence des deux complexes de prothrombine/phospholipides différents. La vitesse d'adsorption est contrôlée par la diffusion, avec une couche d'eau immobilisée à la surface de 20 µm d'épaisseur.Phospholipid monolayers consisting of mixtures of phosphatidylserine and phosphatidylcholine were deposited on chromium slides. Binding of prothrombin to these layers was measured in buffered physiological saline. Evidence is obtained for the existence of two different phospholipid/prothrombin complexes. The adsorption velocity is diffusion-controled with an apparent "unstirred layer" at the surface of 20 µm thickness