3,598 research outputs found

    Local-global principles for norm one tori over semi-global fields

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    Let K be a complete discretely valued field with residue field k and F be a function field of a curve over K. Let L/F be a Galois extension of degree n. If n is coprime to char(k), then under some assumptions on k(e.g. k is algebraically closed or a finite field) and on the geometry of the curve, we show that there is a local-global principle with respect to discrete valuations for the norms from the extension L/F

    Should Sputum Smear Examination Be Carried Out at the End of the Intensive Phase and End of Treatment in Sputum Smear Negative Pulmonary TB Patients?

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    The Indian guidelines on following up sputum smear-negative Pulmonary tuberculosis (PTB) patients differ from the current World Health Organization (WHO) guidelines in that the former recommends two follow up sputum examinations (once at the end of intensive phase and the other at the end of treatment) while the latter recommends only one follow up sputum smear microscopy examination, which is done at the end of the intensive phase. This study was conducted to examine if there was any added value in performing an additional sputum smear examination at the end of treatment within the context of a national TB program

    Local-global principles for multinorm tori over semi-global fields

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    Let KK be a complete discretely valued field with the residue field κ\kappa. Assume that cohomological dimension of κ\kappa is less than or equal to 11 (for example, κ\kappa is an algebraically closed field or a finite field). Let FF be the function field of a curve over KK. Let nn be a squarefree positive integer not divisible by char(κ)(\kappa). Then for any two degree nn abelian extensions, we prove that the local-global principle holds for the associated multinorm torus with respect to discrete valuations. Let X\mathscr{X} be a regular proper model of FF such that the reduced special fibre XX is a union of regular curves with normal crossings. Suppose that κ\kappa is algebraically closed with char(κ)2char(\kappa)\neq 2. If the graph associated to X\mathscr{X} is a tree (e.g. F=K(t)F = K(t)) then we show that the same local-global principle holds for the multinorm torus associated to finitely many abelian extensions where one of the extensions is quadratic and others are of degree not divisible by 44.Comment: to appear in Israel Journal of Mathematics. arXiv admin note: text overlap with arXiv:1904.0096

    A short hairpin RNA screen of interferon-stimulated genes identifies a novel negative regulator of the cellular antiviral response

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    ABSTRACT The type I interferon (IFN) signaling pathway restricts infection of many divergent families of RNA and DNA viruses by inducing hundreds of IFN-stimulated genes (ISGs), some of which have direct antiviral activity. We screened 813 short hairpin RNA (shRNA) constructs targeting 245 human ISGs using a flow cytometry approach to identify genes that modulated infection of West Nile virus (WNV) in IFN-β-treated human cells. Thirty ISGs with inhibitory effects against WNV were identified, including several novel genes that had antiviral activity against related and unrelated positive-strand RNA viruses. We also defined one ISG, activating signal cointegrator complex 3 (ASCC3), which functioned as a negative regulator of the host defense response. Silencing of ASCC3 resulted in upregulation of multiple antiviral ISGs, which correlated with inhibition of infection of several positive-strand RNA viruses. Reciprocally, ectopic expression of human ASCC3 or mouse Ascc3 resulted in downregulation of ISGs and increased viral infection. Mechanism-of-action and RNA sequencing studies revealed that ASCC3 functions to modulate ISG expression in an IRF-3- and IRF-7-dependent manner. Compared to prior ectopic ISG expression studies, our shRNA screen identified novel ISGs that restrict infection of WNV and other viruses and defined a new counterregulatory ISG, ASCC3, which tempers cell-intrinsic immunity. IMPORTANCE West Nile virus (WNV) is a mosquito-transmitted virus that continues to pose a threat to public health. Innate immune responses, especially those downstream of type I interferon (IFN) signaling, are critical for controlling virus infection and spread. We performed a genetic screen using a gene silencing approach and identified 30 interferon-stimulated genes (ISGs) that contributed to the host antiviral response against WNV. As part of this screen, we also identified a novel negative regulatory protein, ASCC3, which dampens expression of ISGs, including those with antiviral or proinflammatory activity. In summary, our studies define a series of heretofore-uncharacterized ISGs with antiviral effects against multiple viruses or counterregulatory effects that temper IFN signaling and likely minimize immune-mediated pathology

    Counterexamples to a conjecture of M. Pellegrini and P. Shumyatsky

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    In this article, we provide counterexamples to a conjecture of M. Pellegrini and P. Shumyatsky which states that each coset of the centralizer of an involution in a finite non-abelian simple group GG contains an odd order element, unless G=PSL(n,2)G=\text{PSL}(n,2) for n4n\geq 4. More precisely, we show that the conjecture does not hold for the alternating group A2nA_{2^n} for all n4n\geq 4

    Dielectric and Raman studies of Ba-0.06(Na1/2Bi1/2)(0.94)TiO3-NaNbO3 ceramics

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    In this work the X-ray diffraction, scanning electron microscopy, Raman and dielectric studies of lead free perovskite (1-x)Ba-0.06(Na1/2Bi1/2)(0.94)TiO3-xNaNbO(3) (0 <= x <= 1.0) ceramics, prepared using a standard solid state reaction method, were investigated. X-ray diffraction studies of all the ceramics suggested the formation of single phase with crystal structure transforming from rhombohedral-tetragonal to orthorhombic symmetry with the increase in NaNbO3 content. Raman spectra also confirmed the formation of solid solution without any new phase. Dielectric studies showed that the phase transition is of diffusive character and diffusivity parameter decreases with increasing NaNbO3 content. The compositional fluctuation was considered to be the main cause of diffusivity

    Alternating groups as products of cycle classes - II

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    Given integers k,l2k,l\geq 2, where either ll is odd or kk is even, let n(k,l)n(k,l) denote the largest integer nn such that each element of AnA_n is a product of kk many ll-cycles. In 2008, M. Herzog, G. Kaplan and A. Lev conjectured that 2kl3n(k,l)2kl3+1\lfloor \frac{2kl}{3} \rfloor \leq n(k,l)\leq \lfloor \frac{2kl}{3}\rfloor+1. It is known that the conjecture holds when k=2,3,4k=2,3,4. Moreover, it is also true when 3l3\mid l. In this article, we determine the exact value of n(k,l)n(k,l) when 3l3\nmid l and k5k\geq 5. As an immediate consequence, we get that n(k,l)<2kl3n(k,l)<\lfloor \frac{2kl}{3}\rfloor when k5k\geq 5, which shows that the above conjecture is not true in general. In fact, the difference between the exact value of n(k,l)n(k,l) and the conjectured value grows linearly in terms of kk. Our results also generalize the case of k=2,3,4k=2,3,4.Comment: 27 page

    A ruled residue theorem for function fields of elliptic curves

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    It is shown that a valuation of residue characteristic different from 22 and 33 on a field EE has at most one extension to the function field of an elliptic curve over EE, for which the residue field extension is transcendental but not ruled. The cases where such an extension is present are characterised

    THE FUNCTIONAL ROLE OF MELATONIN AND KISSPEPTIN IN FISH REPRODUCTION

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    Reproduction of fish generally governed by the counter interaction of some endogenous and exogenous cues like endocrine signals and one or more environmental factors such as photoperiod, temperature, rainfall, food availability, salinity etc. Study indicates that it depends on hypothalamo-hypophysis-gonadal axis. In gonad, gametogenesis is ordered by various hormones followed by their interactions with proper tissues leading to breed at a specific time of the year. Melatonin, a neuroendocrine hormone, has a significant physiological role in the regulation of seasonality and gonadal development of fish. On the other hand, receptor independent actions or free radical scavenging role of melatonin at different levels of hypothalamo-hypophysis-gonadal axis is not yet clear.&nbsp; In recent years, focus has been given to study the of kisspeptin peptides potentiality on gonadal development especially during the transitional period of puberty and gonadal relapse. The relationship of kisspeptin and gonadotropin-releasing hormone is a good illustration of the kisspeptin system. The role of kisspeptin and melatonin in the reproduction of fish is an important subject of research. &nbsp;The potency of kisspeptin and melatonin on reproductive maturation and gonadotropin release in response to environmental cues and the regulation of secretion of gonadotropin-releasing hormone by kisspeptin and melatonin are also the important objectives of the present review
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