2,528 research outputs found

    Comment on "Electromagnetic dissociation of ^8B and the astrophysical S-factor for ^7Be(p,gamma)^8B"

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    Recently, Davids and Typel recommended a "low" value of S_{17}(0) based on fits to published direct and Coulomb dissociation data, in which they excluded the precise result of Junghans et al. We show that their statistical analysis is incorrect, due to a substantial underestimate of the experimental uncertainties, and leads to conclusions that are not supported by a proper analysis.Comment: submitted to Phys. Rev.

    Tailoring supercurrent confinement in graphene bilayer weak links

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    The Josephson effect is one of the most studied macroscopic quantum phenomena in condensed matter physics and has been an essential part of the quantum technologies development over the last decades. It is already used in many applications such as magnetometry, metrology, quantum computing, detectors or electronic refrigeration. However, developing devices in which the induced superconductivity can be monitored, both spatially and in its magnitude, remains a serious challenge. In this work, we have used local gates to control confinement, amplitude and density profile of the supercurrent induced in one-dimensional nanoscale constrictions, defined in bilayer graphene-hexagonal boron nitride van der Waals heterostructures. The combination of resistance gate maps, out-of-equilibrium transport, magnetic interferometry measurements, analytical and numerical modelling enables us to explore highly tunable superconducting weak links. Our study opens the path way to design more complex superconducting circuits based on this principle such as electronic interferometers or transition-edge sensors

    Toxicity Analysis in the ADEBAR Trial: Sequential Anthracycline-Taxane Therapy Compared with FEC120 for the Adjuvant Treatment of High-Risk Breast Cancer

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    Background: Data from meta-analyses have shown taxane-containing therapies to be superior to anthracycline-based treatments for high-risk breast cancer. Patients and Methods: The ADEBAR trial was a multicenter phase Ill trial in which patients with lymph node-positive breast cancer were prospectively randomized for either sequential anthracycline-taxane or FEC120 therapy. Patients received 4x epirubicin (90 mg/m(2)) and cyclophosphamide (600 mg/m(2)) every 3 weeks (q3w), followed by 4x docetaxel (100 mg/m(2)) q3w (EC-Doc arm), or 6x epirubicin (60 mg/m(2)) and 5-fluorouracil (500 mg/m(2)) on days 1 and 8 and cyclophosphamide (75 mg/m(2)) on days 1-14, q4w (FEC arm). We compared both arms with respect to toxicity and feasibility. Results: Hematological toxicity was found significantly more often in the FEC arm. Febrile neutropenia was seen in 11.3% of patients in the FEC arm and in 8.4% of patients in the EC-Doc arm (p = 0.027). Non-hematological side effects of grade 3/4 were rarely seen in either arm. Therapy was terminated due to toxicity in 3.7% of the patients in the EC-Doc arm and in 8.0% of the patients in the FEC arm (p = 0.0009). Conclusion: The sequential anthracycline-taxane regimen is a well-tolerated and feasible alternative to FEC120 therapy

    The global aerosol-cloud first indirect effect estimated using MODIS, MERRA, and AeroCom

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    Aerosol-cloud interactions (ACI) represent a significant source of forcing uncertainty in global climate models (GCMs). Estimates of radiative forcing due to ACI in Fifth Assessment Report range from −0.5 to −2.5 W m−2. A portion of this uncertainty is related to the first indirect, or Twomey, effect whereby aerosols act as nuclei for cloud droplets to condense upon. At constant liquid water content this increases the number of cloud droplets (Nd) and thus increases the cloud albedo. In this study we use remote-sensing estimates of Nd within stratocumulus regions in combination with state-of-the-art aerosol reanalysis from Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA2) to diagnose how aerosols affect Nd. As in previous studies, Nd is related to sulfate mass through a power law relationship. The slope of the log-log relationship between Nd and SO4 in maritime stratocumulus is found to be 0.31, which is similar to the range of 0.2–0.8 from previous in situ studies and remote-sensing studies in the pristine Southern Ocean. Using preindustrial emissions models, the change in Nd between preindustrial and present day is estimated. Nd is inferred to have more than tripled in some regions. Cloud properties from Moderate Resolution Imaging Spectroradiometer (MODIS) are used to estimate the radiative forcing due to this change in Nd. The Twomey effect operating in isolation is estimated to create a radiative forcing of −0.97 ± 0.23 W m−2 relative to the preindustrial era

    Synaptotagmin-7 Is an Asynchronous Calcium Sensor for Synaptic Transmission in Neurons Expressing SNAP-23

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    Synchronization of neurotransmitter release with the presynaptic action potential is essential for maintaining fidelity of information transfer in the central nervous system. However, synchronous release is frequently accompanied by an asynchronous release component that builds up during repetitive stimulation, and can even play a dominant role in some synapses. Here, we show that substitution of SNAP-23 for SNAP-25 in mouse autaptic glutamatergic hippocampal neurons results in asynchronous release and a higher frequency of spontaneous release events (mEPSCs). Use of neurons from double-knock-out (SNAP-25, synaptotagmin-7) mice in combination with viral transduction showed that SNAP-23-driven release is triggered by endogenous synaptotagmin-7. In the absence of synaptotagmin-7 release became even more asynchronous, and the spontaneous release rate increased even more, indicating that synaptotagmin-7 acts to synchronize release and suppress spontaneous release. However, compared to synaptotagmin-1, synaptotagmin-7 is a both leaky and asynchronous calcium sensor. In the presence of SNAP-25, consequences of the elimination of synaptotagmin-7 were small or absent, indicating that the protein pairs SNAP-25/synaptotagmin-1 and SNAP-23/synaptotagmin-7 might act as mutually exclusive calcium sensors. Expression of fusion proteins between pHluorin (pH-sensitive GFP) and synaptotagmin-1 or -7 showed that vesicles that fuse using the SNAP-23/synaptotagmin-7 combination contained synaptotagmin-1, while synaptotagmin-7 barely displayed activity-dependent trafficking between vesicle and plasma membrane, implying that it acts as a plasma membrane calcium sensor. Overall, these findings support the idea of alternative syt∶SNARE combinations driving release with different kinetics and fidelity

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