630 research outputs found

    Effects of Weather on Foraging Success and Hunting Frequency in Winter-Irruptive Snowy Owls (\u3ci\u3eBubo scandiacus\u3c/i\u3e) in Upstate New York

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    The effects of weather on an individual can often alter the population dynamics of a species. Knowledge of how weather influences individual behavior is therefore essential in understanding its full impact in the context of population ecology. Snowy Owls (Bubo scandiacus) exhibit expensive long-distance migrations in winters following population irruptions. During irruptive movements, many owls migrate past the southernmost extent of their traditional wintering grounds, the mechanism for which is still debated. We propose and test the “milder climate” hypothesis; Snowy Owls wintering in lower latitudes are better able to meet their metabolic demands due to higher temperatures and lower snow cover. During the Snowy Owl irruption of 2014–2015, we examined this hypothesis by assessing the influence of local weather variables on foraging success, frequency of prey capture attempts, and overall activity budgets in a sample of wintering Snowy Owls in New York, USA. We used eBird, an online citizen science resource, to help locate Snowy Owls, which we observed from an automobile. We found that none of the weather variables tested affected foraging success. However, the lack of effect of snow depth on foraging success may suggest that hearing is more important for hunting in Snowy Owls than previously thought. Hunting frequency decreased with increasing temperatures, suggesting Snowy Owls were better able to meet their metabolic demands in higher temperatures. We thus offer support for the milder climate hypothesis; Snowy Owls wintering in lower latitudes may be able to offset the energetic expenses of long-distance movements

    Improving zero-error classical communication with entanglement

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    Given one or more uses of a classical channel, only a certain number of messages can be transmitted with zero probability of error. The study of this number and its asymptotic behaviour constitutes the field of classical zero-error information theory, the quantum generalisation of which has started to develop recently. We show that, given a single use of certain classical channels, entangled states of a system shared by the sender and receiver can be used to increase the number of (classical) messages which can be sent with no chance of error. In particular, we show how to construct such a channel based on any proof of the Bell-Kochen-Specker theorem. This is a new example of the use of quantum effects to improve the performance of a classical task. We investigate the connection between this phenomenon and that of ``pseudo-telepathy'' games. The use of generalised non-signalling correlations to assist in this task is also considered. In this case, a particularly elegant theory results and, remarkably, it is sometimes possible to transmit information with zero-error using a channel with no unassisted zero-error capacity.Comment: 6 pages, 2 figures. Version 2 is the same as the journal version plus figure 1 and the non-signalling box exampl

    White Beam Synchrotron X-Ray Topography of Gallium Arsenide

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    The defect structure of gallium arsenide is being examined using white beam transmission topography. The specimens under examination are cut-and-polished, three inch diameter, single crystal substrates from various suppliers in the “as received” condition. The goal of this continuing program is to first document the existence of various crystallographic defect structures and then to establish their effect on the performance of microwave integrated circuits subsequently fabricated on the wafers. Success in establishing such a correlation might permit the use of an x-ray diffraction measurement to screen incoming material, eliminating marginal substrates and achieving a corresponding increase in yield

    Islet Autoantibody Standardization Program 2018 Workshop:Interlaboratory Comparison of Glutamic Acid Decarboxylase Autoantibody Assay Performance

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    BACKGROUND: The Islet Autoantibody Standardization Program (IASP) aims to improve the performance of immunoassays measuring type 1 diabetes (T1D)-associated autoantibodies and the concordance of results among laboratories. IASP organizes international interlaboratory assay comparison studies in which blinded serum samples are distributed to participating laboratories, followed by centralized collection and analysis of results, providing participants with an unbiased comparative assessment. In this report, we describe the results of glutamic acid decarboxylase autoantibody (GADA) assays presented in the IASP 2018 workshop. METHODS: In May 2018, IASP distributed to participants uniquely coded sera from 43 new-onset T1D patients, 7 multiple autoantibody-positive nondiabetic individuals, and 90 blood donors. Results were analyzed for the following metrics: sensitivity, specificity, accuracy, area under the ROC curve (ROC-AUC), partial ROC-AUC at 95% specificity (pAUC95), and concordance of qualitative and quantitative results. RESULTS: Thirty-seven laboratories submitted results from a total of 48 different GADA assays adopting 9 different formats. The median ROC-AUC and pAUC95 of all assays were 0.87 [interquartile range (IQR), 0.83-0.89] and 0.036 (IQR, 0.032-0.039), respectively. Large differences in pAUC95 (range, 0.001-0.0411) were observed across assays. Of formats widely adopted, bridge ELISAs showed the best median pAUC95 (0.039; range, 0.036-0.041). CONCLUSIONS: Several novel assay formats submitted to this study showed heterogeneous performance. In 2018, the majority of the best performing GADA immunoassays consisted of novel or established nonradioactive tests that proved on a par or superior to the radiobinding assay, the previous gold standard assay format for GADA measurement

    NRG Oncology/RTOG 0921: A phase 2 study of postoperative intensity-modulated radiotherapy with concurrent cisplatin and bevacizumab followed by carboplatin and paclitaxel for patients with endometrial cancer.

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    BACKGROUND: The current study was conducted to assess acute and late adverse events (AEs), overall survival (OS), pelvic failure, regional failure, distant failure, and disease-free survival in a prospective phase 2 clinical trial of bevacizumab and pelvic intensity-modulated radiotherapy (IMRT) with chemotherapy in patients with high-risk endometrial cancer. METHODS: Patients underwent a hysterectomy and lymph node removal, and had ≥1 of the following high-risk factors: grade 3 carcinoma with \u3e50% myometrial invasion, grade 2 or 3 disease with any cervical stromal invasion, or known extrauterine extension confined to the pelvis. Treatment included pelvic IMRT and concurrent cisplatin on days 1 and 29 of radiation and bevacizumab (at a dose of 5 mg/kg on days 1, 15, and 29 of radiation) followed by adjuvant carboplatin and paclitaxel for 4 cycles. The primary endpoint was grade ≥3 AEs occurring within the first 90 days (toxicity was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0]). RESULTS: A total of 34 patients were accrued from November 2009 through December 2011, 30 of whom were eligible and received study treatment. Seven of 30 patients (23.3%; 1-sided 95% confidence interval, 10.6%-36.0%) developed grade ≥3 treatment-related nonhematologic toxicities within 90 days; an additional 6 patients experienced grade ≥3 toxicities between 90 and 365 days after treatment. The 2-year OS rate was 96.7% and the disease-free survival rate was 79.1%. No patient developed a within-field pelvic failure and no patients with International Federation of Gynecology and Obstetrics stage I to IIIA disease developed disease recurrence after a median follow-up of 26 months. CONCLUSIONS: Postoperative bevacizumab added to chemotherapy and pelvic IMRT appears to be well tolerated and results in high OS rates at 2 years for patients with high-risk endometrial carcinoma

    First lattice QCD study of the gluonic structure of light nuclei

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    The role of gluons in the structure of the nucleon and light nuclei is investigated using lattice quantum chromodynamics (QCD) calculations. The first moment of the unpolarized gluon distribution is studied in nuclei up to atomic number A = 3 at quark masses corresponding to pion masses of m(pi) similar to 450 and 806 MeV. Nuclear modification of this quantity defines a gluonic analogue of the EMC effect and is constrained to be less than similar to 10% in these nuclei. This is consistent with expectations from phenomenological quark distributions and the momentum sum rule. In the deuteron, the combination of gluon distributions corresponding to the b(1) structure function is found to have a small first moment compared with the corresponding momentum fraction. The first moment of the gluon transversity structure function is also investigated in the spin-1 deuteron, where a nonzero signal is observed at m(pi) similar to 806 MeV. This is the first indication of gluon contributions to nuclear structure that can not be associated with an individual nucleon

    Baryon-baryon interactions and spin-flavor symmetry from lattice quantum chromodynamics

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    Lattice quantum chromodynamics is used to constrain the interactions of two octet baryons at the SU(3) flavor-symmetric point, with quark masses that are heavier than those in nature (equal to that of the physical strange quark mass and corresponding to a pion mass of approximate to 806 MeV). Specifically, the S-wave scattering phase shifts of two-baryon systems at low energies are obtained with the application of Luscher\u27s formalism, mapping the energy eigenvalues of two interacting baryons in a finite volume to the two-particle scattering amplitudes below the relevant inelastic thresholds. The leading-order low-energy scattering parameters in the two-nucleon systems that were previously obtained at these quark masses are determined with a refined analysis, and the scattering parameters in two other channels containing the S and. baryons are constrained for the first time. It is found that the values of these parameters are consistent with an approximate SU(6) spin-flavor symmetry in the nuclear and hypernuclear forces that is predicted in the large-N-c limit of QCD. The two distinct SU(6)-invariant interactions between two baryons are constrained for the first time at this value of the quark masses, and their values indicate an approximate accidental SU(16) symmetry. The SU(3) irreps containing the NN(S-1(0)), NN(S-3(1)) and 1/root 2(Xi(0)n)+Xi(-)p)(S-3(1)) channels unambiguously exhibit a single bound state, while the irrep containing the Sigma(+)p(S-3(1)) channel exhibits a state that is consistent with either a bound state or a scattering state close to threshold. These results are in agreement with the previous conclusions of the NPLQCD collaboration regarding the existence of two-nucleon bound states at this value of the quark masses
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