4,123 research outputs found

    Signatures of unconventional pairing in near-vortex electronic structure of LiFeAs

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    A major question in Fe-based superconductors remains the structure of the pairing, in particular whether it is of unconventional nature. The electronic structure near vortices can serve as a platform for phase-sensitive measurements to answer this question. By solving Bogoliubov-de Gennes equations for LiFeAs, we calculate the energy-dependent local electronic structure near a vortex for different nodeless gap-structure possibilities. At low energies, the local density of states (LDOS) around a vortex is determined by the normal-state electronic structure. However, at energies closer to the gap value, the LDOS can distinguish an anisotropic from a conventional isotropic s-wave gap. We show within our self-consistent calculation that in addition, the local gap profile differs between a conventional and an unconventional pairing. We explain this through admixing of a secondary order parameter within Ginzburg-Landau theory. In-field scanning tunneling spectroscopy near vortices can therefore be used as a real-space probe of the gap structure

    Interspecific competition underlying mutualistic networks

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    The architecture of bipartite networks linking two classes of constituents is affected by the interactions within each class. For the bipartite networks representing the mutualistic relationship between pollinating animals and plants, it has been known that their degree distributions are broad but often deviate from power-law form, more significantly for plants than animals. Here we consider a model for the evolution of the mutualistic networks and find that their topology is strongly dependent on the asymmetry and non-linearity of the preferential selection of mutualistic partners. Real-world mutualistic networks analyzed in the framework of the model show that a new animal species determines its partners not only by their attractiveness but also as a result of the competition with pre-existing animals, which leads to the stretched-exponential degree distributions of plant species.Comment: 5 pages, 3 figures, accepted version in PR

    A Bacterial Virulence Protein Promotes Pathogenicity by Inhibiting the Bacterium’s Own F1Fo ATP Synthase

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    SummarySeveral intracellular pathogens, including Salmonella enterica and Mycobacterium tuberculosis, require the virulence protein MgtC to survive within macrophages and to cause a lethal infection in mice. We now report that, unlike secreted virulence factors that target the host vacuolar ATPase to withstand phagosomal acidity, the MgtC protein acts on Salmonella’s own F1Fo ATP synthase. This complex couples proton translocation to ATP synthesis/hydrolysis and is required for virulence. We establish that MgtC interacts with the a subunit of the F1Fo ATP synthase, hindering ATP-driven proton translocation and NADH-driven ATP synthesis in inverted vesicles. An mgtC null mutant displays heightened ATP levels and an acidic cytoplasm, whereas mgtC overexpression decreases ATP levels. A single amino acid substitution in MgtC that prevents binding to the F1Fo ATP synthase abolishes control of ATP levels and attenuates pathogenicity. MgtC provides a singular example of a virulence protein that promotes pathogenicity by interfering with another virulence protein

    The Dendritic magnetic avalanches in carbon-free MgB2_2 thin films with and without a deposited Au layer

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    From the magneto optics images (MOI), the dendritic magnetic avalanche is known to appear dominantly for thin films of the newly discovered MgB2_2. To clarify the origin of this phenomenon, we studied in detail the MOI of carbon-free MgB2_2 thin films with and without a deposited gold layer. The MOI indicated carbon contamination was not the main source of the avalanche. The MOI clearly showed that the deposition of metallic gold deposition on top of a MgB2_2 thin film improved its thermal stability and suppressed the sudden appearance of the dendritic flux avalanche. This is consistent with the previous observation of flux noise in the magnetization.Comment: 9 pages, 4 figeure

    Korean Home Learning Environment and Parent Characteristics Influencing Children\u27s Expressive and Receptive Language Abilities

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    This study analyzed data derived from ‘The Panel Study on Korean Children’ implemented by the Korea Institute of Child Care & Education (KICCE). Two scales, EC-HOME and REVT were used to investigate specific types of home environments and parent characteristics beneficial in the facilitation of children’s receptive and expressive language development. The Step-wise Multiple Regression Analysis identified four variables (Responsively, Physical Environment, Father Education, and Mother Habitation) that made a significant contribution to children’s receptive language development, and six different variables (Mother Education, Academic Stimulation, and Physical Environment, Acceptance, Mother’s Current Job Status, and Communicative Stimulation) for expressive language development. This study found that home learning environment is a more significant factor for children\u27s receptive and expressive language development than parent demographic characteristics with the exception of the education level of parents, current job status of the mother, and habitation status of the mother

    Intravenous Brivaracetam in the Management of Acute Seizures in the Hospital Setting: A Scoping Review

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    Background Clinical considerations for drug treatment of acute seizures involve variables such as safety, tolerability, drug-drug interactions, dosage, route of administration, and alterations in pharmacokinetics because of critical illness. Therapy options that are easily and quickly administered without dilution, well tolerated, and effective are needed for the treatment of acute seizures. The objective of this review is to focus on the clinical considerations relating to the use of intravenous brivaracetam (IV BRV) for the treatment of acute seizures in the hospital, focusing on critically ill patients. Methods This was a scoping literature review of PubMed from inception to April 13, 2021, and search of the American Academy of Neurology (AAN) 2021 Annual Meeting website for English language publications/conference abstracts reporting the results of IV BRV use in hospitalized patients, particularly in the critical care setting. Outcomes of interest relating to the clinical pharmacology, safety, tolerability, efficacy, and effectiveness of IV BRV were reviewed and are discussed. Results Twelve studies were included for analysis. One study showed that plasma concentrations of IV BRV 15 min after the first dose were similar between patients receiving IV BRV as bolus or infusion. IV BRV was generally well tolerated in patients with acute seizures in the hospital setting, with a low incidence of individual TEAEs classified as behavioral disorders. IV BRV demonstrated efficacy and effectiveness and had a rapid onset, with clinical and electrophysiological improvement in seizures observed within minutes. Although outside of the approved label, findings from several studies suggest that IV BRV reduces seizures and is generally well tolerated in patients with status epilepticus. Conclusions IV BRV shows effectiveness, and is generally well tolerated in the management of acute seizures in hospitalized patients where rapid administration is needed, representing a clinically relevant antiseizure medication for potential use in the critical care setting
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