3,152 research outputs found

    The third moment of quadratic Dirichlet L-functions

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    We study the third moment of quadratic Dirichlet L-functions, obtaining an error term of size O(X3/4+ε)O(X^{3/4 + \varepsilon}).Comment: 27 pages. v2: modified a remark on p.

    Mott Transition of MnO under Pressure: Comparison of Correlated Band Theories

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    The electronic structure, magnetic moment, and volume collapse of MnO under pressure are obtained from four different correlated band theory methods; local density approximation + Hubbard U (LDA+U), pseudopotential self-interaction correction (pseudo-SIC), the hybrid functional (combined local exchange plus Hartree-Fock exchange), and the local spin density SIC (SIC-LSD) method. Each method treats correlation among the five Mn 3d orbitals (per spin), including their hybridization with three O 2p2p orbitals in the valence bands and their changes with pressure. The focus is on comparison of the methods for rocksalt MnO (neglecting the observed transition to the NiAs structure in the 90-100 GPa range). Each method predicts a first-order volume collapse, but with variation in the predicted volume and critical pressure. Accompanying the volume collapse is a moment collapse, which for all methods is from high-spin to low-spin (5/2 to 1/2), not to nonmagnetic as the simplest scenario would have. The specific manner in which the transition occurs varies considerably among the methods: pseudo-SIC and SIC-LSD give insulator-to-metal, while LDA+U gives insulator-to-insulator and the hybrid method gives an insulator-to-semimetal transition. Projected densities of states above and below the transition are presented for each of the methods and used to analyze the character of each transition. In some cases the rhombohedral symmetry of the antiferromagnetically ordered phase clearly influences the character of the transition.Comment: 14 pages, 9 figures. A 7 institute collaboration, Updated versio

    Weyl group multiple Dirichlet series constructed from quadratic characters

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    We construct multiple Dirichlet series in several complex variables whose coefficients involve quadratic residue symbols. The series are shown to have an analytic continuation and satisfy a certain group of functional equations. These are the first examples of an infinite collection of unstable Weyl group multiple Dirichlet series in greater than two variables.Comment: incorporated referee's comment

    Current pharmacological treatment of painful diabetic neuropathy: A narrative review

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    Background and Objectives: Distal symmetrical polyneuropathy (DSPN) is one of the most common chronic complications of diabetes mellitus. Although it is usually characterized by progressive sensory loss, some patients may develop chronic pain. Assessment of DSPN is not difficult, but the biggest challenge is making the correct diagnosis and choosing the right treatment. The treatment of DSPN has three primary objectives: glycemic control, pathogenic mechanisms, and pain management. The aim of this brief narrative review is to summarize the current pharmacological treatment of painful DSPN. It also summarizes knowledge on pathogenesis-oriented therapy, which is generally overlooked in many publications and guidelines. Materials and Methods: The present review reports the relevant information available on DSPN treatment. The search was performed on PubMed, Cochrane, Semantic Scholar, Medline, Scopus, and Cochrane Library databases, including among others the terms “distal symmetrical polyneuropathy”, “neuropathic pain treatment”, “diabetic neuropathy”, “diabetes complications”, ”glycaemic control”, “antidepressants”, “opioids”, and “anticonvulsants”. Results: First-line drugs include antidepressants (selective serotonin reuptake inhibitors and tricyclic antidepressants) and pregabalin. Second- and third-line drugs include opioids and topical analgesics. While potentially effective in the treatment of neuropathic pain, opioids are not considered to be the first choice because of adverse reactions and addiction concerns. Conclusions: DSPN is a common complication in patients with diabetes, and severely affects the quality of life of these patients. Although multiple therapies are available, the guidelines and recommendations regarding the treatment of diabetic neuropathy have failed to offer a unitary consensus, which often hinders the therapeutic options in clinical practice

    Bacterial ribosome requires multiple L12 dimers for efficient initiation and elongation of protein synthesis involving IF2 and EF-G

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    The ribosomal stalk in bacteria is composed of four or six copies of L12 proteins arranged in dimers that bind to the adjacent sites on protein L10, spanning 10 amino acids each from the L10 C-terminus. To study why multiple L12 dimers are required on the ribosome, we created a chromosomally engineered Escherichia coli strain, JE105, in which the peripheral L12 dimer binding site was deleted. Thus JE105 harbors ribosomes with only a single L12 dimer. Compared to MG1655, the parental strain with two L12 dimers, JE105 showed significant growth defect suggesting suboptimal function of the ribosomes with one L12 dimer. When tested in a cell-free reconstituted transcription–translation assay the synthesis of a full-length protein, firefly luciferase, was notably slower with JE105 70S ribosomes and 50S subunits. Further, in vitro analysis by fast kinetics revealed that single L12 dimer ribosomes from JE105 are defective in two major steps of translation, namely initiation and elongation involving translational GTPases IF2 and EF-G. Varying number of L12 dimers on the ribosome can be a mechanism in bacteria for modulating the rate of translation in response to growth condition
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