1,706 research outputs found

    How many manuscripts should I peer review per year?

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    Peer review provides the foundation for the scholarly publishing system. The conventional peer review system consists of using authors of articles as reviewers for other colleagues' manuscripts in a collaborative-basis system. However, authors complain about a theoretical overwhelming number of invitations to peer review. It seems that authors feel that they are invited to review many more manuscripts than they should when taking into account their participation in the scholarly publishing system. The high number of scientific journals and the existence of predatory journals were reported as potential causes of this excessive number of reviews required. In this editorial, we demonstrate that the number of reviewers required to publish a given number of articles depends exclusively on the journals' rejection rate and the number of reviewers intended per manuscript. Several initiatives to overcome the peer review crises are suggested

    Direct observation of melting in a 2-D superconducting vortex lattice

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    Topological defects such as dislocations and disclinations are predicted to determine the twodimensional (2-D) melting transition. In 2-D superconducting vortex lattices, macroscopic measurements evidence melting close to the transition to the normal state. However, the direct observation at the scale of individual vortices of the melting sequence has never been performed. Here we provide step by step imaging through scanning tunneling spectroscopy of a 2-D system of vortices up to the melting transition in a focused-ion-beam nanodeposited W-based superconducting thin film. We show directly the transition into an isotropic liquid below the superconducting critical temperature. Before that, we find a hexatic phase, characterized by the appearance of free dislocations, and a smectic-like phase, possibly originated through partial disclination unbinding. These results represent a significant step in the understanding of melting of 2-D systems, with impact across several research fields, such as liquid crystal molecules, or lipids in membranes.Comment: Submitted to Nature Physic

    Root temperature and energy consumption at different cable depths in electrically heated substrates

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    A finite element method-based model of a substrate heated by an electric heating cable buried in a thermal isolated container was experimentally validated with root mean square error values of root zone temperature ranging 0.25 to 0.62 ÂșC. The two-dimensional transient model allowed variations in the physical properties of the substrate with temperature, water content and depth. The operation of nine configurations of a heating cable buried in sand at different depths (50 to 450 mm, at 50 mm intervals) at 200 mm spacing was simulated and assessed. The validated model was used to perform 24-h simulations applying boundary conditions, and substrate moisture content was experimentally obtained at a mean substrate surface temperature of 13.98 ÂșC. Such simulations reproduced the operation of the heating system by setting a reference temperature of 20 ÂșC at the control point in the root zone. Burying the heating cable in the surface layers of the substrate caused large temperature gradients and high heat losses through the substrate surface. Accordingly, average temperature in the root zone increased with heating cable depth, up to the 200 mm depth. For greater depths, temperature in the root zone was constant. The ON/OFF control was most effective with the heating cable buried in the root zone and at control point temperatures of 20 ± 1 ÂșC. Burying the heating cable in the surface layers required higher energy consumption, up to 28 % at 50 mm. The most efficient heating cable depth was 350 mm, with a daily energy consumption of 6750 kJ m-2

    Variational Mean Field approach to the Double Exchange Model

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    It has been recently shown that the double exchange Hamiltonian, with weak antiferromagnetic interactions, has a richer variety of first and second order transitions than previously anticipated, and that such transitions are consistent with the magnetic properties of manganites. Here we present a thorough discussion of the variational Mean Field approach that leads to the these results. We also show that the effect of the Berry phase turns out to be crucial to produce first order Paramagnetic-Ferromagnetic transitions near half filling with transition temperatures compatible with the experimental situation. The computation relies on two crucial facts: the use of a Mean Field ansatz that retains the complexity of a system of electrons with off-diagonal disorder, not fully taken into account by the Mean Field techniques, and the small but significant antiferromagnetic superexchange interaction between the localized spins.Comment: 13 pages, 11 postscript figures, revte

    Severe Hypoalbuminemia at Day 90 Predicts Worse Nonrelapse Mortality and Overall Survival after Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myelogenous Leukemia and Myelodysplastic Syndrome

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    Because patients who undergo allogeneic hematopoietic cell transplantation (allo-HCT) remain in the vicinity of the transplant center for approximately 90 days posttransplantation, identifying prognostic factors to determine those at immediate higher risk of mortality is essential. A normal serum albumin level generally denotes healthiness. We evaluated the prognostic significance of day 90 hypoalbuminemia (and other clinical, pharmacologic, and laboratory variables) in 163 patients, median age 48 years (range, 19-69 years), who underwent allo-HCT for acute myelogenous leukemia (n = 124) or myelodysplastic syndrome (n = 39). Day 90 hypoalbuminemia (serum albumin <3.0 g/dL) was associated with worse nonrelapse mortality (NRM) and poor overall survival (OS). The estimated 1- and 2-year cumulative incidence rates of NRM were 48% and 52%, respectively, and the corresponding OS rates were 7% and 3%. Serum albumin level <3.0 g/dL and Karnofsky score <80 at day 90 were strong independent predictors of worse NRM and OS in multivariate analysis. These results support day 90 hypoalbuminemia as an adverse prognostic marker for NRM and OS after allo-HCT for acute myelogenous leukemia and myelodysplastic syndrome

    An update to Hippocampome.org by integrating single-cell phenotypes with circuit function in vivo

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    Understanding brain operation demands linking basic behavioral traits to cell-type specific dynamics of different brain-wide subcircuits. This requires a system to classify the basic operational modes of neurons and circuits. Single-cell phenotyping of firing behavior during ongoing oscillations in vivo has provided a large body of evidence on entorhinal-hippocampal function, but data are dispersed and diverse. Here, we mined literature to search for information regarding the phase-timing dynamics of over 100 hippocampal/entorhinal neuron types defined in . We identified missing and unresolved pieces of knowledge (e.g., the preferred theta phase for a specific neuron type) and complemented the dataset with our own new data. By confronting the effect of brain state and recording methods, we highlight the equivalences and differences across conditions and offer a number of novel observations. We show how a heuristic approach based on oscillatory features of morphologically identified neurons can aid in classifying extracellular recordings of single cells and discuss future opportunities and challenges towards integrating single-cell phenotypes with circuit function.Peer reviewe

    Acid-base titration of melanocortin peptides: evidence of Trp rotational conformer interconversion

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    Abstract: Tryptophan time-resolved fluorescence was used to monitor acid-base titration properties of ␣-melanocyte stimulating hormone (␣-MSH 2, 6

    Gastroduodenal injury after radioembolization of hepatic tumors

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    Radioembolization is a new tool for the treatment of hepatic tumors that consists in the injection of biocompatible microspheres carrying radioisotopes into the hepatic artery or its branches. METHODS: We have performed radioembolization in 78 patients with hepatic tumors using resin-based microspheres loaded with yttrium-90. All patients were previously evaluated to minimize the risk of hazardous irradiation to nontarget organs and to obtain the data needed for dose calculation. RESULTS: We report a complication found in three cases (3.8%) that consists of abdominal pain resulting from gastroduodenal lesions and that had a chronic, insidious course. Microscopically, microspheres were detected in the specimens obtained from all affected gastric areas. Since these gastroduodenal lesions do not appear when nonradiating microspheres are injected in animals, lesions are likely to be due to radiation and not to an ischemic effect of vascular occlusion by spheres. CONCLUSIONS: We believe that a pretreatment evaluation that includes a more thorough scrutiny of the hepatic vascularization in search of small collaterals connecting to the gastroduodenal tract can help prevent this awkward complicatio

    High-pressure single-crystal neutron diffraction to 10 GPa by angle-dispersive techniques

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    Techniques have been developed that allow the measurement of accurate single-crystal neutron-diffraction data at pressures up to 10 GPa, using angle-dispersive methods. High-quality data have been collected up to 10 GPa, to a resolution of sinΞ/λ ≃ 1.5 Å−1, from samples of size 3–4 mm^{3}. This article presents the methods developed to mount and centre the sample accurately on the instrument; to reduce the background and hence increase the precision of the measured reflection intensities; and to increase further the accessible region of reciprocal space with a single sample loading. Developments are also highlighted, with a view to increasing the range of both science and pressures that can be achieved at the Institut Laue–Langevin reactor source using single-crystal techniques.</jats:p
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