231 research outputs found

    A Case Study: Effects of Tutoring on the Sight Word Vocabulary of a Nonreader

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    The purpose of this study was to provide remedial instruction in reading to a ten year old nonreading student enrolled in the Ellensburg School District and to develop a case study that outlined the diagnostic and remedial procedures used with the subject. The case study approach was chosen as a way to document the progress of a single student whose initial diagnosis was as a nonreader. Because the initial diagnosis indicated a need to establish a sight word vocabulary, early instructional methods focused on this area

    The effects of administering different metaphylactic antimicrobials on growth performance and health outcomes of high-risk, newly received feedlot steers

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    Bovine respiratory disease (BRD) is the primary animal health concern facing feedlot producers. Many antimicrobial mitigation strategies are available, but few studies have compared feedlot performance during both the receiving and finishing periods following application of different antimicrobials used as metaphylaxis at arrival. The objective of this study was to compare antimicrobial metaphylaxis methods on clinical health and growth performance across both the receiving and finishing periods. A total of 238 multiple-sourced steers in two source blocks were used in a generalized complete block design. The four treatments included: 1) a negative control, 5 mL of sterile saline injected subcutaneously (CON); 2) subcutaneous administration of florfenicol at 40 mg/kg of BW (NUF); 3) subcutaneous administration of ceftiofur in the posterior aspect of the ear at 6.6 mg/kg of BW (EXC); and 4) subcutaneous administration of tulathromycin at 2.5 mg/kg of BW (DRA). The morbidity rate for the first treatment of BRD was decreased for the DRA and EXC treatments compared to CON and NUF (P \u3c 0.01). Additionally, average daily gain (ADG), dry matter intake (DMI), and gain-to-feed (G:F) were greater (P ≤ 0.02) in the DRA treatment during the receiving period compared to all other treatments. The ADG was also greater (P \u3c 0.05) for EXC than the CON treatment throughout the finishing period. Nonetheless, other growth performance variables did not differ among metaphylactic treatments during the finishing period (P ≥ 0.14). Likewise, no differences in carcass characteristics or liver abscess score were observed (P ≥ 0.18). All complete blood count (CBC) variables were affected by day (P ≤ 0.01) except mean corpuscular hemoglobin concentration (P = 0.29). Treatment × time interactions were observed for platelet count, white blood cell (WBC) count, monocyte count and percentage, and lymphocyte percentage (P ≤ 0.03). However, there were no observed hematological variables that differed among treatment (P ≥ 0.10). The results indicate that some commercially available antimicrobials labeled for metaphylactic use are more efficacious than others in decreasing morbidity rate

    Search for Extended Sources of Neutrino Emission in the Galactic Plane with IceCube

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    The Galactic plane, harboring a diffuse neutrino flux, is a particularly interesting target to study potential cosmic-ray acceleration sites. Recent gamma-ray observations by HAWC and LHAASO have presented evidence for multiple Galactic sources that exhibit a spatially extended morphology and have energy spectra continuing beyond 100 TeV. A fraction of such emission could be produced by interactions of accelerated hadronic cosmic rays, resulting in an excess of high-energy neutrinos clustered near these regions. Using 10 years of IceCube data comprising track-like events that originate from charged-current muon neutrino interactions, we perform a dedicated search for extended neutrino sources in the Galaxy. We find no evidence for time-integrated neutrino emission from the potential extended sources studied in the Galactic plane. The most significant location, at 2.6σ\sigma post-trials, is a 1.7^\circ sized region coincident with the unidentified TeV gamma-ray source 3HWC J1951+266. We provide strong constraints on hadronic emission from several regions in the Galaxy.Comment: 13 pages, 4 figures, 5 tables including an appendix. Accepted for publication in Astrophysical Journa

    Search for High-energy Neutrino Emission from Galactic X-Ray Binaries with IceCube

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    We present the first comprehensive search for high-energy neutrino emission from high- and low-mass X-ray binaries conducted by IceCube. Galactic X-ray binaries are long-standing candidates for the source of Galactic hadronic cosmic rays and neutrinos. The compact object in these systems can be the site of cosmic-ray acceleration, and neutrinos can be produced by interactions of cosmic rays with radiation or gas, in the jet of a microquasar, in the stellar wind, or in the atmosphere of the companion star. We study X-ray binaries using 7.5 yr of IceCube data with three separate analyses. In the first, we search for periodic neutrino emission from 55 binaries in the Northern Sky with known orbital periods. In the second, the X-ray light curves of 102 binaries across the entire sky are used as templates to search for time-dependent neutrino emission. Finally, we search for time-integrated emission of neutrinos for a list of 4 notable binaries identified as microquasars. In the absence of a significant excess, we place upper limits on the neutrino flux for each hypothesis and compare our results with theoretical predictions for several binaries. In addition, we evaluate the sensitivity of the next generation neutrino telescope at the South Pole, IceCube-Gen2, and demonstrate its power to identify potential neutrino emission from these binary sources in the Galaxy

    Measurement of atmospheric neutrino mixing with improved IceCube DeepCore calibration and data processing

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    We describe a new data sample of IceCube DeepCore and report on the latest measurement of atmospheric neutrino oscillations obtained with data recorded between 2011–2019. The sample includes significant improvements in data calibration, detector simulation, and data processing, and the analysis benefits from a sophisticated treatment of systematic uncertainties, with significantly greater level of detail since our last study. By measuring the relative fluxes of neutrino flavors as a function of their reconstructed energies and arrival directions we constrain the atmospheric neutrino mixing parameters to be sin2θ23=0.51±0.05 and Δm232=2.41±0.07×10−3  eV2, assuming a normal mass ordering. The errors include both statistical and systematic uncertainties. The resulting 40% reduction in the error of both parameters with respect to our previous result makes this the most precise measurement of oscillation parameters using atmospheric neutrinos. Our results are also compatible and complementary to those obtained using neutrino beams from accelerators, which are obtained at lower neutrino energies and are subject to different sources of uncertainties

    Searches for Neutrinos from LHAASO ultra-high-energy {\gamma}-ray sources using the IceCube Neutrino Observatory

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    Galactic PeVatrons are Galactic sources theorized to accelerate cosmic rays up to PeV in energy. The accelerated cosmic rays are expected to interact hadronically with nearby ambient gas or the interstellar medium, resulting in {\gamma}-rays and neutrinos. Recently, the Large High Altitude Air Shower Observatory (LHAASO) identified 12 {\gamma}-ray sources with emissions above 100 TeV, making them candidates for PeV cosmic-ray accelerators (PeVatrons). While at these high energies the Klein-Nishina effect suppresses exponentially leptonic emission from Galactic sources, evidence for neutrino emission would unequivocally confirm hadronic acceleration. Here, we present the results of a search for neutrinos from these {\gamma}-ray sources and stacking searches testing for excess neutrino emission from all 12 sources as well as their subcatalogs of supernova remnants and pulsar wind nebulae with 11 years of track events from the IceCube Neutrino Observatory. No significant emissions were found. Based on the resulting limits, we place constraints on the fraction of {\gamma}-ray flux originating from the hadronic processes in the Crab Nebula and LHAASOJ2226+6057

    Limits on Neutrino Emission from GRB 221009A from MeV to PeV using the IceCube Neutrino Observatory

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    Gamma-ray bursts (GRBs) have long been considered a possible source of high-energy neutrinos. While no correlations have yet been detected between high-energy neutrinos and GRBs, the recent observation of GRB 221009A - the brightest GRB observed by Fermi-GBM to date and the first one to be observed above an energy of 10 TeV - provides a unique opportunity to test for hadronic emission. In this paper, we leverage the wide energy range of the IceCube Neutrino Observatory to search for neutrinos from GRB 221009A. We find no significant deviation from background expectation across event samples ranging from MeV to PeV energies, placing stringent upper limits on the neutrino emission from this source.Comment: Version in ApJ Letters Focus on the Ultra-luminous Gamma-Ray Burst GRB 221009

    Measurement of Atmospheric Neutrino Mixing with Improved IceCube DeepCore Calibration and Data Processing

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    We describe a new data sample of IceCube DeepCore and report on the latest measurement of atmospheric neutrino oscillations obtained with data recorded between 2011-2019. The sample includes significant improvements in data calibration, detector simulation, and data processing, and the analysis benefits from a detailed treatment of systematic uncertainties, with significantly higher level of detail since our last study. By measuring the relative fluxes of neutrino flavors as a function of their reconstructed energies and arrival directions we constrain the atmospheric neutrino mixing parameters to be sin2θ23=0.51±0.05\sin^2\theta_{23} = 0.51\pm 0.05 and Δm322=2.41±0.07×103eV2\Delta m^2_{32} = 2.41\pm0.07\times 10^{-3}\mathrm{eV}^2, assuming a normal mass ordering. The resulting 40\% reduction in the error of both parameters with respect to our previous result makes this the most precise measurement of oscillation parameters using atmospheric neutrinos. Our results are also compatible and complementary to those obtained using neutrino beams from accelerators, which are obtained at lower neutrino energies and are subject to different sources of uncertainties

    Searches for Neutrinos from Large High Altitude Air Shower Observatory Ultra-high-energy γ-Ray Sources Using the IceCube Neutrino Observatory

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    Density of GeV muons in air showers measured with IceTop

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    We present a measurement of the density of GeV muons in near-vertical air showers using three years of data recorded by the IceTop array at the South Pole. Depending on the shower size, the muon densities have been measured at lateral distances between 200 and 1000 m. From these lateral distributions, we derive the muon densities as functions of energy at reference distances of 600 and 800 m for primary energies between 2.5 and 40 PeV and between 9 and 120 PeV, respectively. The muon densities are determined using, as a baseline, the hadronic interaction model Sibyll 2.1 together with various composition models. The measurements are consistent with the predicted muon densities within these baseline interaction and composition models. The measured muon densities have also been compared to simulations using the post-LHC models EPOS-LHC and QGSJet-II.04. The result of this comparison is that the post-LHC models together with any given composition model yield higher muon densities than observed. This is in contrast to the observations above 1 EeV where all model simulations yield for any mass composition lower muon densities than the measured ones. The post-LHC models in general feature higher muon densities so that the agreement with experimental data at the highest energies is improved but the muon densities are not correct in the energy range between 2.5 and about 100 PeV
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