697 research outputs found

    Study of Fields Associated with Spin-I Particles Carrying Electric and Magnetic Charges

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    Uplift of Himalaya and it’s implications on the evolution of Indian monsoon

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    Abstract HKT-ISTP 2013 A

    Recurrent Modification of a Conserved Cis-Regulatory Element Underlies Fruit Fly Pigmentation Diversity

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    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

    Second Quantization and Interaction of Electromagnetic Fields for Non Zero Mass System in Angular Momentum Basis : II

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    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

    Colossal dielectric constants in transition-metal oxides

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    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

    SARS-CoV-2: comparison of IgG levels at 9 months post second dose of vaccination in COVID-survivor and COVID-naïve healthcare workers

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    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.

    Efficacy of modified co-synch plus protocol with or without progesterone device for estrus induction and conception rate in Murrah buffaloes under field conditions during summer season

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    The aim of present study was to evaluate efficacy of Modified Co-Synch Plus Protocol with or without progesterone device for estrus induction, progesterone concentration and conception rate in Murrah buffaloes under field conditions during summer season. The study was conducted using 30 postpartum anestrus Murrah buffaloes divided in two groups. In Group 1 (n=15), the buffaloes were administered with PMSG 400 IU on -3 day, Buserelin acetate 10 μg, on day 0, cloprostenol 500 μg, on day 7, and on day 9 h CG 2000 IU. Thereafter, timed artificial insemination (TAI) was done at the time of h CG injection and 24 h later once again. In Group 2 (n=15), the buffaloes were treated with same protocol as Group 1, in addition to progesterone device, which was placed in vagina on day 0 and was removed on day 7 of the protocol. Thereafter, TAI was done as in Group 1. Plasma Progesterone concentration was estimated during the different days (-3, 0, 7, 9 and 10 day) of protocol. The estrus induction rate was 86.6% and 100% in Group 1 and Group 2 respectively showing very good estrus (46%), good estrus (30.7%) and poor estrus (23.07%) in Group 1 while very good estrus (46.6%), good estrus (40%) and poor estrus (13.4%) in Group 2. The conception rates in Group 1 and 2, at FTAI and overall including subsequent estrus were 46.2% and 61.53% and 53.33% and 73.33% respectively. The plasma progesterone concentrations were higher (P&lt;0.05) on day 7 in Group 2 than Group 1 (4.16±0.32 vs 2.30±0.24 ng/ml). Both two protocol treatment during non breeding season resulted in very good estrus induction and acceptable conception rate in anestrous buffaloes

    Clinical profile and treatment of infantile spasms using vigabatrin and ACTH - a developing country perspective

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    Background: Infantile spasms represent a serious epileptic syndrome that occurs in the early infantile age. ACTH and Vigabatrin are actively investigated drugs in its treatment. This study describes the comparison of their efficacy in a large series of Patients with infantile spasms from Pakistan. Methods: All Patients with infantile spasms who presented to Aga Khan University Hospital, Karachi, Pakistan from January, 2006 to April, 2008 were included in this study. Inclusion criteria were clinical symptoms of infantile spasms, hypsarrythmia or modified hyparrythmia on electroencephalography, at least six months of follow-up period and receipt of any of the two drugs mentioned above. The type of drug distribution was random according to the availability, cost and ease of administration. Results: Fifty six cases fulfilled the inclusion criteria. 62.5% were males. Mean age at onset of seizures was 5 +/- 1.4 months. Fifty two (92.8%) Patients demonstrated hypsarrythmia on electroencephalography. 64.3% cases were identified as symptomatic while 19.6% were cryptogenic and 16.1% were idiopathic. Eighteen Patients received ACTH while 38 Patients received Vigabatrin as first line therapy. Initial response to first line therapy was similar (50% for ACTH and 55.3% for Vigabatrin). Overall, the symptomatic and idiopathic groups responded better to Vigabatrin. The relapse rate was higher for ACTH as compared to Vigabatrin (55.5% vs. 33.3%) when considering the first line therapy. Four Patients evolved to Lennox-Gastaut variant, all of these Patients had initially received Vigabatrin and then ACTH. Conclusion: Vigabatrin and ACTH showed no significant difference in the initial treatment of infantile spasms. However, Patients receiving ACTH were 1.2 times more likely to relapse as compared to the Patients receiving Vigabatrin when considering monotherapy. We suggest that Vigabatrin should be the initial drug of choice in Patients presenting with infantile spasms. However, larger studies from developing countries are required to validate the therapeutic trends observed in this study
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