564 research outputs found
Second Quantization and Interaction of Electromagnetic Fields for Non Zero Mass System in Angular Momentum Basis : II
The study of interaction and second quantization of electromagnetic fields
for non-zero mass system has boon undertaken in angular momentum
basis and the selection rules for omission and absorption of a massive
particle are derived. Reducton of real transverse electromagnetic
vector potential for non-zero mass system has been derived in terms of
irreducible representations of proper, ortho-chronous, inhomogeneous
Lorentz group in angular momentum basi
Uplift of Himalaya and it’s implications on the evolution of Indian monsoon
Abstract HKT-ISTP 2013
A
SARS-CoV-2: comparison of IgG levels at 9 months post second dose of vaccination in COVID-survivor and COVID-naïve healthcare workers
Background: Natural (asymptomatic/symptomatic COVID-19 infection) and artificial (vaccination) exposure to the pathogen represent two modes of acquiring active immunity. No definitive guidelines exist regarding whether COVID-survivors (with infection/re-infection/re-re-infection in the three COVID-19 waves) require a modified vaccination schedule. Most countries are offering a third vaccine dose and many are contemplating a fourth dose. Our aim was to gauge the IgG-antibody levels 9m post second vaccination in healthcare workers (HCW) and compare these with IgG-levels 1m post-vaccination in the same cohort for any decline, and to compare the post-vaccination IgG-levels in COVID-survivors and COVID-naïve HCW at 9m.Methods: This prospective observational single-centric cohort study included 63 HCW of either sex, aged 18-70y who completed 9m post-vaccination. The IgG-titre was tested at 9-10m post second vaccination in COVID-survivors and COVID-naïve HCW.Results: At 1m and 9m post-vaccination IgG-levels in COVID-survivors (23.097±4.58 and 15.103±4.367 respectively; p<0.0001) and COVID-naïve HCW (16.277±6.36 and 9.793±6.928 respectively; p=0.0013) had unequal variance (Welsch test; p=0.0022 at 9m). 9/31 COVID-naïve HCW but none of the 32 COVID-survivors tested COVID-positive in the second wave post second vaccination. 11/31 and 3/32 HCW belonging to the former and latter groups developed COVID-19 in the third wave consequently deferring their third/precautionary vaccination.Conclusions: Although HCW with IgG-levels in all brackets developed COVID-19, the severity of symptoms corresponded with the IgG-levels. COVID-19 is here to stay, but in peaceful co-existence in endemic proportions. Considering evidence that immunity acquired by vaccination/natural infection is ephemeral, re-invention of vaccines to match the ever-mutating virus is foreseen.
Thoracic trident pigmentation in Drosophila melanogaster: latitudinal and altitudinal clines in Indian populations
International audienc
Recurrent Modification of a Conserved Cis-Regulatory Element Underlies Fruit Fly Pigmentation Diversity
The development of morphological traits occurs through the collective action of networks of genes connected at the level of gene expression. As any node in a network may be a target of evolutionary change, the recurrent targeting of the same node would indicate that the path of evolution is biased for the relevant trait and network. Although examples of parallel evolution have implicated recurrent modification of the same gene and cis-regulatory element (CRE), little is known about the mutational and molecular paths of parallel CRE evolution. In Drosophila melanogaster fruit flies, the Bric-à-brac (Bab) transcription factors control the development of a suite of sexually dimorphic traits on the posterior abdomen. Female-specific Bab expression is regulated by the dimorphic element, a CRE that possesses direct inputs from body plan (ABD-B) and sex-determination (DSX) transcription factors. Here, we find that the recurrent evolutionary modification of this CRE underlies both intraspecific and interspecific variation in female pigmentation in the melanogaster species group. By reconstructing the sequence and regulatory activity of the ancestral Drosophila melanogaster dimorphic element, we demonstrate that a handful of mutations were sufficient to create independent CRE alleles with differing activities. Moreover, intraspecific and interspecific dimorphic element evolution proceeded with little to no alterations to the known body plan and sex-determination regulatory linkages. Collectively, our findings represent an example where the paths of evolution appear biased to a specific CRE, and drastic changes in function were accompanied by deep conservation of key regulatory linkages. © 2013 Rogers et al
Colossal dielectric constants in transition-metal oxides
Many transition-metal oxides show very large ("colossal") magnitudes of the
dielectric constant and thus have immense potential for applications in modern
microelectronics and for the development of new capacitance-based
energy-storage devices. In the present work, we thoroughly discuss the
mechanisms that can lead to colossal values of the dielectric constant,
especially emphasising effects generated by external and internal interfaces,
including electronic phase separation. In addition, we provide a detailed
overview and discussion of the dielectric properties of CaCu3Ti4O12 and related
systems, which is today's most investigated material with colossal dielectric
constant. Also a variety of further transition-metal oxides with large
dielectric constants are treated in detail, among them the system La2-xSrxNiO4
where electronic phase separation may play a role in the generation of a
colossal dielectric constant.Comment: 31 pages, 18 figures, submitted to Eur. Phys. J. for publication in
the Special Topics volume "Cooperative Phenomena in Solids: Metal-Insulator
Transitions and Ordering of Microscopic Degrees of Freedom
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