988 research outputs found

    The organophosphate pesticide chlorpyrifos affects form deprivation myopia

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    PURPOSE. The effects of the anticholinesterase organophosphate pesticide chlorpyrifos (CPF) on the refractive development of the eye were examined. Form deprivation was used to induce eye growth to address the previously reported relationship between organophosphate pesticide use and the incidence of myopia. METHODS. Chickens, a well-established animal model for experimental myopia and organophosphate neurotoxicity, were dosed with chlorpyrifos (3 mg/kg per day, orally, from day 2 to day 9 after hatching) or corn oil vehicle (VEH) with or without monocular form deprivation (MFD) over the same period. The set of dependent measures included the refractive state of each eye measured using retinoscopy, axial dimensions determined with A-scan ultrasound, and intraocular pressure. RESULTS. Dosing with CPF yielded an inhibition of 35% butyrylcholinesterase in plasma and 45% acetylcholinesterase in brain. MFD resulted in a significant degree of myopia in form-deprived eyes resulting from significant lengthening of the vitreal chamber of the eye. CPF significantly reduced the effect of MFD, resulting in less myopic eyes (mean refraction: VEH-MFD = -16.2 ± 2.3 diopters; CPF-MFD = - 11.1 ± 1.8 diopters) with significantly shorter vitreal chambers. Nonoccluded eyes were, on average, slightly hyperopic. Treatment with CPF for 1 week in the absence of MFD led to no significant change in ocular dimensions or refraction relative to controls. CONCLUSIONS. The use of form deprivation as a challenge suggests that CPF treatment interferes with the visual regulation of eye growth

    Proteases as Insecticidal Agents

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    Proteases from a variety of sources (viruses, bacteria, fungi, plants, and insects) have toxicity towards insects. Some of these insecticidal proteases evolved as venom components, herbivore resistance factors, or microbial pathogenicity factors, while other proteases play roles in insect development or digestion, but exert an insecticidal effect when over-expressed from genetically engineered plants or microbial pathogens. Many of these proteases are cysteine proteases, although insect-toxic metalloproteases and serine proteases have also been examined. The sites of protease toxic activity range from the insect midgut to the hemocoel (body cavity) to the cuticle. This review discusses these insecticidal proteases along with their evaluation and use as potential pesticides

    Mosaic structural variation in children with developmental disorders

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    Delineating the genetic causes of developmental disorders is an area of active investigation. Mosaic structural abnormalities, defined as copy number or loss of heterozygosity events that are large and present in only a subset of cells, have been detected in 0.2–1.0% of children ascertained for clinical genetic testing. However, the frequency among healthy children in the community is not well characterized, which, if known, could inform better interpretation of the pathogenic burden of this mutational category in children with developmental disorders. In a case–control analysis, we compared the rate of large-scale mosaicism between 1303 children with developmental disorders and 5094 children lacking developmental disorders, using an analytical pipeline we developed, and identified a substantial enrichment in cases (odds ratio = 39.4, P-value 1.073e − 6). A meta-analysis that included frequency estimates among an additional 7000 children with congenital diseases yielded an even stronger statistical enrichment (P-value 1.784e − 11). In addition, to maximize the detection of low-clonality events in probands, we applied a trio-based mosaic detection algorithm, which detected two additional events in probands, including an individual with genome-wide suspected chimerism. In total, we detected 12 structural mosaic abnormalities among 1303 children (0.9%). Given the burden of mosaicism detected in cases, we suspected that many of the events detected in probands were pathogenic. Scrutiny of the genotypic–phenotypic relationship of each detected variant assessed that the majority of events are very likely pathogenic. This work quantifies the burden of structural mosaicism as a cause of developmental disorders

    IceCube Search for Neutrinos Coincident with Compact Binary Mergers from LIGO-Virgo's First Gravitational-Wave Transient Catalog

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    Using the IceCube Neutrino Observatory, we search for high-energy neutrino emission coincident with compact binary mergers observed by the LIGO and Virgo gravitational wave (GW) detectors during their first and second observing runs. We present results from two searches targeting emission coincident with the sky localization of each gravitational wave event within a 1000 second time window centered around the reported merger time. One search uses a model-independent unbinned maximum likelihood analysis, which uses neutrino data from IceCube to search for point-like neutrino sources consistent with the sky localization of GW events. The other uses the Low-Latency Algorithm for Multi-messenger Astrophysics, which incorporates astrophysical priors through a Bayesian framework and includes LIGO-Virgo detector characteristics to determine the association between the GW source and the neutrinos. No significant neutrino coincidence is seen by either search during the first two observing runs of the LIGO-Virgo detectors. We set upper limits on the time-integrated neutrino emission within the 1000 second window for each of the 11 GW events. These limits range from 0.02-0.7 GeV cm2\mathrm{GeV~cm^{-2}}. We also set limits on the total isotropic equivalent energy, EisoE_{\mathrm{iso}}, emitted in high-energy neutrinos by each GW event. These limits range from 1.7 ×\times 1051^{51} - 1.8 ×\times 1055^{55} erg. We conclude with an outlook for LIGO-Virgo observing run O3, during which both analyses are running in real time

    Characteristics of the diffuse astrophysical electron and tau neutrino flux with six years of IceCube high energy cascade data

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    We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010 -- 2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (90%\sim 90 \%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16TeV16\,\mathrm{TeV} to 2.6PeV2.6\,\mathrm{PeV}, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be γ=2.53±0.07\gamma=2.53\pm0.07 and a flux normalization for each neutrino flavor of ϕastro=1.660.27+0.25\phi_{astro} = 1.66^{+0.25}_{-0.27} at E0=100TeVE_{0} = 100\, \mathrm{TeV}, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices γ2.28\gamma\leq2.28 at 3σ\ge3\sigma significance level. Due to high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below 100TeV\sim100\,{\rm{TeV}} compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p-value 0.06\ge 0.06). The sizable and smooth flux measured below 100TeV\sim 100\,{\rm{TeV}} remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi-LAT, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma-rays.Comment: 4 figures, 4 tables, includes supplementary materia

    Multimessenger Gamma-Ray and Neutrino Coincidence Alerts using HAWC and IceCube sub-threshold Data

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    The High Altitude Water Cherenkov (HAWC) and IceCube observatories, through the Astrophysical Multimessenger Observatory Network (AMON) framework, have developed a multimessenger joint search for extragalactic astrophysical sources. This analysis looks for sources that emit both cosmic neutrinos and gamma rays that are produced in photo-hadronic or hadronic interactions. The AMON system is running continuously, receiving sub-threshold data (i.e. data that is not suited on its own to do astrophysical searches) from HAWC and IceCube, and combining them in real-time. We present here the analysis algorithm, as well as results from archival data collected between June 2015 and August 2018, with a total live-time of 3.0 years. During this period we found two coincident events that have a false alarm rate (FAR) of <1<1 coincidence per year, consistent with the background expectations. The real-time implementation of the analysis in the AMON system began on November 20th, 2019, and issues alerts to the community through the Gamma-ray Coordinates Network with a FAR threshold of <4<4 coincidences per year.Comment: 14 pages, 5 figures, 3 table

    Paper Trails: Following the Money

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    In many recent elections, the candidates who raise the most money have a better shot at winning, so candidates must raise millions of dollars to win an election. A top question to consider in all elections: Where is the money coming from? Posting about the financing behind federal elections from In All Things - an online hub committed to the claim that the life, death, and resurrection of Jesus Christ has implications for the entire world. http://inallthings.org/paper-trails-following-the-money

    Searching for eV-scale sterile neutrinos with eight years of atmospheric neutrinos at the IceCube neutrino telescope

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    We report in detail on searches for eV-scale sterile neutrinos, in the context of a 3+1 model, using eight years of data from the IceCube neutrino telescope. By analyzing the reconstructed energies and zenith angles of 305,735 atmospheric νμ\nu_\mu and νˉμ\bar{\nu}_\mu events we construct confidence intervals in two analysis spaces: sin2(2θ24)\sin^2 (2\theta_{24}) vs. Δm412\Delta m^2_{41} under the conservative assumption θ34=0\theta_{34}=0; and sin2(2θ24)\sin^2(2\theta_{24}) vs. sin2(2θ34)\sin^2 (2\theta_{34}) given sufficiently large Δm412\Delta m^2_{41} that fast oscillation features are unresolvable. Detailed discussions of the event selection, systematic uncertainties, and fitting procedures are presented. No strong evidence for sterile neutrinos is found, and the best-fit likelihood is consistent with the no sterile neutrino hypothesis with a p-value of 8\% in the first analysis space and 19\% in the second.Comment: This long-form paper is a companion to the letter "An eV-scale sterile neutrino search using eight years of atmospheric muon neutrino data from the IceCube Neutrino Observatory". v2: update other experiments contours on results plo

    An eV-scale sterile neutrino search using eight years of atmospheric muon neutrino data from the IceCube Neutrino Observatory

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    The results of a 3+1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305,735 muon neutrino events are analyzed in reconstructed energy-zenith space to test for signatures of a matter-enhanced oscillation that would occur given a sterile neutrino state with a mass-squared differences between 0.01\,eV2^2 and 100\,eV2^2. The best-fit point is found to be at sin2(2θ24)=0.10\sin^2(2\theta_{24})=0.10 and Δm412=4.5eV2\Delta m_{41}^2 = 4.5{\rm eV}^2, which is consistent with the no sterile neutrino hypothesis with a p-value of 8.0\%.Comment: 11 pages, 5 figures. This letter is supported by the long-form paper "Searching for eV-scale sterile neutrinos with eight years of atmospheric neutrinos at the IceCube neutrino telescope," also appearing on arXiv. Digital data release available at: https://github.com/icecube/HE-Sterile-8year-data-releas
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