637 research outputs found

    Effects of a glyphosate-based herbicide on soil animal trophic groups and associated ecosystem functioning in a northern agricultural field

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    Despite an increasing concern of consequences of using vast amounts of glyphosate-based herbicides in agroecosystems, their potential effects on non-target soil organisms and soil functioning are mostly unknown. It has also been argued that fields in northern latitudes should be under special surveillance as the short active period of decomposers may restrict glyphosate degradation. We investigated the effects of a glyphosate- based herbicide, Roundup, on the abundance of enchytraeids and nematodes, both essential groups in decomposer food webs, and plant litter mass loss and soil availability of mineral N in a two-year agricultural field setting in south-west Finland. Our experiment consisted of (1) non-treated weed plots, (2) plots, where weeds were killed by hoeing, and (3) plots treated with both Roundup and hoeing. We found that killing plants by hoeing had drastic effects on soil fauna and functioning, and apparently, distinguishing these effects from direct glyphosate effects is profoundly important when evaluating glyphosate risks in soils. In contrast, the effects of Roundup on soil fauna and functioning were minor and transient and no glyphosate remains were found in the soil at the end of the experiment. These results suggest that side-effects can be minor and glyphosate degradation effective also in soil under northern climatic conditions

    Relationships between geomagnetic Ар-indeх and parameters of the immunity in patients with neuroendocrine-immune complex dysfunction in former sportsmen

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    Background. The effect of geomagnetism on human immunity has so far been studied through long-term observations. Recently, we have been detected the immediate immunotropic effects of the disturbances of the geomagnetic field (Ap-index) at multiple sclerosis patients. The aim of this study was to identify the immunotropic effects of geomagnetism on another contingent of people. Material and methods. The object of observation were 21 men (24-63 y) and 20 women (33-62 y) with neuroendocrine-immune complex dysfunction. Each patient was tested twice with an interval of 4 days. Observations were carried out on 09.06. and 13.06. 2015, 14.09 and 18.09. 2015, 27-28.03. and 04-05.04. 2018, 28.01. and 01.02. 2019. Retrospectively we recorded the geomagnetic Ap-Index on the day of testing and during the previous 7 days, using resource https://www.spaceweatherlive.com/. The content of subpopulations of lymphocytes expressing CD3, CD4, CD25, CD8, CD22 and CD56 receptors as well as the serum concentration of circulating immune complexes, immunoglobulins classes M, G, A, C-reactive protein and IL-1β was determined. The state of phagocytic function of neutrophils estimated by microbial count and phagocytic and killing indices against Staphylococcus aureus and Escherichia coli. Results. During the week, the average level of Ap-index ranged from 7 to 13 nT. Maximum coefficients of multiple correlation with immunity parameters were detected for Ap-index on the eve of blood sampling (R=0,768) and 5 days before it (R=0,758) while the minimum on 3 (R=0,541) and 2 (R=0,479) days before sampling. The canonical correlation between Ap-indices for 7 days before and on the day of testing, on the one hand, and the immunity parameters - on the other hand, was very strong: R=0,921; R2=0,849; χ2(200)=375; p<10-6. Conclusion. Disturbances of the geomagnetic field (Ap-index) has a significant immediate modulating effect on the immune parameters, mostly phagocytosis completeness, Igg A and M serum concentration, T-helper and B lymphocytes as well as eosinophils, rod-shaped neutrophils and monocytes blood level

    The Main Results of the Borexino Experiment

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    The main physical results on the registration of solar neutrinos and the search for rare processes obtained by the Borexino collaboration to date are presented.Comment: 8 pages, 8 figgures, To be published as Proceedings of the Third Annual Large Hadron Collider Physics Conference, St. Petersburg, Russia, 201

    Determination of the muon charge sign with the dipolar spectrometers of the OPERA experiment

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    The OPERA long-baseline neutrino-oscillation experiment has observed the direct appearance of ντ\nu_\tau in the CNGS νμ\nu_\mu beam. Two large muon magnetic spectrometers are used to identify muons produced in the τ\tau leptonic decay and in νμCC\nu_\mu^{CC} interactions by measuring their charge and momentum. Besides the kinematic analysis of the τ\tau decays, background resulting from the decay of charmed particles produced in νμCC\nu_\mu^{CC} interactions is reduced by efficiently identifying the muon track. A new method for the charge sign determination has been applied, via a weighted angular matching of the straight track-segments reconstructed in the different parts of the dipole magnets. Results obtained for Monte Carlo and real data are presented. Comparison with a method where no matching is used shows a significant reduction of up to 40\% of the fraction of wrongly determined charges.Comment: 10 pages. Improvements in the tex

    New limits on heavy sterile neutrino mixing in 8B{^{8}\rm{B}}-decay obtained with the Borexino detector

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    If heavy neutrinos with mass mνHm_{\nu_{H}}\geq2me m_e are produced in the Sun via the decay 8B8Be+e++νH{^8\rm{B}} \rightarrow {^8\rm{Be}} + e^+ + \nu_H in a side branch of pp-chain, they would undergo the observable decay into an electron, a positron and a light neutrino νHνL+e++e\nu_{H}\rightarrow\nu_{L}+e^++e^-. In the present work Borexino data are used to set a bound on the existence of such decays. We constrain the mixing of a heavy neutrino with mass 1.5 MeV mνH\leq m_{\nu_{H}} \le 14 MeV to be UeH2(1034×106)|U_{eH}|^2\leq (10^{-3}-4\times10^{-6}) respectively. These are tighter limits on the mixing parameters than obtained in previous experiments at nuclear reactors and accelerators.Comment: 7 pages, 6 figure

    Qweak: A Precision Measurement of the Proton's Weak Charge

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    The Qweak experiment at Jefferson Lab aims to make a 4% measurement of the parity-violating asymmetry in elastic scattering at very low Q2Q^2 of a longitudinally polarized electron beam on a proton target. The experiment will measure the weak charge of the proton, and thus the weak mixing angle at low energy scale, providing a precision test of the Standard Model. Since the value of the weak mixing angle is approximately 1/4, the weak charge of the proton Qwp=14sin2θwQ_w^p = 1-4 \sin^2 \theta_w is suppressed in the Standard Model, making it especially sensitive to the value of the mixing angle and also to possible new physics. The experiment is approved to run at JLab, and the construction plan calls for the hardware to be ready to install in Hall C in 2007. The theoretical context of the experiment and the status of its design are discussed.Comment: 5 pages, 2 figures, LaTeX2e, to be published in CIPANP 2003 proceeding

    Limits on muon-neutrino to tau-neutrino oscillations induced by a sterile neutrino state obtained by OPERA at the CNGS beam

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    The OPERA experiment, exposed to the CERN to Gran Sasso νμ\nu_\mu beam, collected data from 2008 to 2012. Four oscillated ντ\nu_\tau Charged Current interaction candidates have been detected in appearance mode, which are consistent with νμντ\nu_\mu \to \nu_\tau oscillations at the atmospheric Δm2\Delta m^2 within the "standard" three-neutrino framework. In this paper, the OPERA ντ\nu_\tau appearance results are used to derive limits on the mixing parameters of a massive sterile neutrino.Comment: 11 pages, 4 figures; reference to Planck result updated in the Introduction. Submitted to JHE

    Measurement of neutrino flux from the primary proton--proton fusion process in the Sun with Borexino detector

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    Neutrino produced in a chain of nuclear reactions in the Sun starting from the fusion of two protons, for the first time has been detected in a real-time detector in spectrometric mode. The unique properties of the Borexino detector provided an oppurtunity to disentangle pp-neutrino spectrum from the background components. A comparison of the total neutrino flux from the Sun with Solar luminosity in photons provides a test of the stability of the Sun on the 105^{5} years time scale, and sets a strong limit on the power production in the unknown energy sources in the Sun of no more than 4\% of the total energy production at 90\% C.L.Comment: 15 pages, 2 tables, 3 figure
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