174 research outputs found

    Estudo para o melhoramento do sistema cultural da soja no cerrado.

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    Seasonal Migration of Sika Deer in the Oku-Chichibu Mountains, Central Japan

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    Movements and seasonal home ranges of 6 GPS collared sika deer were investigated at the Oku-Chichibu Mountains, central Honshu, from April 2009 to March 2010. All deer migrated between discrete summer and winter home ranges. The linear migration distance ranged from 2.5 to 31.9 km. Mean elevation during the summer and the winter ranged from 980 to 1,782 m, and from 1,204 to 1,723 m, respectively. Two deer were upward migrants and 4 deer were downward migrants. Taking into consideration of the relatively small snow accumulation in the summer home range, the possibility of autumn migration to avoid deep snow is low. The percentage of steep slope in the winter home range was higher than that in the summer. Bamboo grass was not found in the summer home range, but was predominant in the winter home range. Road density decreased in the winter home range compared to the summer. Only 2 out of 6 deer stayed mainly in the wildlife protection area during the winter. Our results indicate that the autumn migration was affected by winter forage and human disturbance, thereby assured the survival of the deer during winter.ArticleMAMMAL STUDY. 37(2):127-137 (2012)journal articl

    A rapid and robust tri-color flow cytometry assay for monitoring malaria parasite development

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    Microscopic examination of Giemsa-stained thin blood smears remains the gold standard method used to quantify and stage malaria parasites. However, this technique is tedious, and requires trained microscopists. We have developed a fast and simple flow cytometry method to quantify and stage, various malaria parasites in red blood cells in whole blood or in vitro cultured Plasmodium falciparum. The parasites were stained with dihydroethidium and Hoechst 33342 or SYBR Green I and leukocytes were identified with an antibody against CD45. Depending on the DNA stains used, samples were analyzed using different models of flow cytometers. This protocol, which does not require any washing steps, allows infected red blood cells to be distinguished from leukocytes, as well as allowing non-infected reticulocytes and normocytes to be identified. It also allows assessing the proportion of parasites at different developmental stages. Lastly, we demonstrate how this technique can be applied to antimalarial drug testing

    Search for Cosmic-ray Boosted Sub-GeV Dark Matter using Recoil Protons at Super-Kamiokande

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    We report a search for cosmic-ray boosted dark matter with protons using the 0.37 megaton×\timesyears data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross-section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross-section between 10−33 cm−210^{-33}\text{ cm}^{-2} and 10−27 cm−210^{-27}\text{ cm}^{-2} for dark matter mass from 10 MeV/c2c^2 to 1 GeV/c2c^2.Comment: With 1-page appendi

    Search for astrophysical electron antineutrinos in Super-Kamiokande with 0.01wt% gadolinium-loaded water

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    We report the first search result for the flux of astrophysical electron antineutrinos for energies O(10) MeV in the gadolinium-loaded Super-Kamiokande (SK) detector. In June 2020, gadolinium was introduced to the ultra-pure water of the SK detector in order to detect neutrons more efficiently. In this new experimental phase, SK-Gd, we can search for electron antineutrinos via inverse beta decay with efficient background rejection and higher signal efficiency thanks to the high efficiency of the neutron tagging technique. In this paper, we report the result for the initial stage of SK-Gd with a 22.5×55222.5\times552 kton⋅day\rm kton\cdot day exposure at 0.01% Gd mass concentration. No significant excess over the expected background in the observed events is found for the neutrino energies below 31.3 MeV. Thus, the flux upper limits are placed at the 90% confidence level. The limits and sensitivities are already comparable with the previous SK result with pure-water (22.5×2970kton⋅day22.5 \times 2970 \rm kton\cdot day) owing to the enhanced neutron tagging

    Performance of SK-Gd's Upgraded Real-time Supernova Monitoring System

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    Among multi-messenger observations of the next galactic core-collapse supernova, Super-Kamiokande (SK) plays a critical role in detecting the emitted supernova neutrinos, determining the direction to the supernova (SN), and notifying the astronomical community of these observations in advance of the optical signal. On 2022, SK has increased the gadolinium dissolved in its water target (SK-Gd) and has achieved a Gd concentration of 0.033%, resulting in enhanced neutron detection capability, which in turn enables more accurate determination of the supernova direction. Accordingly, SK-Gd's real-time supernova monitoring system (Abe te al. 2016b) has been upgraded. SK_SN Notice, a warning system that works together with this monitoring system, was released on December 13, 2021, and is available through GCN Notices (Barthelmy et al. 2000). When the monitoring system detects an SN-like burst of events, SK_SN Notice will automatically distribute an alarm with the reconstructed direction to the supernova candidate within a few minutes. In this paper, we present a systematic study of SK-Gd's response to a simulated galactic SN. Assuming a supernova situated at 10 kpc, neutrino fluxes from six supernova models are used to characterize SK-Gd's pointing accuracy using the same tools as the online monitoring system. The pointing accuracy is found to vary from 3-7∘^\circ depending on the models. However, if the supernova is closer than 10 kpc, SK_SN Notice can issue an alarm with three-degree accuracy, which will benefit follow-up observations by optical telescopes with large fields of view.Comment: 38 pages, 29 figures, 6 table

    Search for Periodic Time Variations of the Solar 8^8B Neutrino Flux Between 1996 and 2018 in Super-Kamiokande

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    We report a search for time variations of the solar 8^8B neutrino flux using 5,804 live days of Super-Kamiokande data collected between May 31, 1996, and May 30, 2018. Super-Kamiokande measured the precise time of each solar neutrino interaction over 22 calendar years to search for solar neutrino flux modulations with unprecedented precision. Periodic modulations are searched for in a data set comprised of five-day interval solar neutrino flux measurements with a maximum likelihood method. We also applied the Lomb-Scargle method to this data set to compare it with previous reports. The only significant modulation found is due to the elliptic orbit of the Earth around the Sun. The observed modulation is consistent with astronomical data: we measured an eccentricity of (1.53±\pm0.35)\,\%, and a perihelion shift is (−-1.5±\pm13.5)\,days.Comment: 8 pages, 5 figures, 2 tables, and data file: "sksolartimevariation5804d.txt

    Measurements of the charge ratio and polarization of cosmic-ray muons with the Super-Kamiokande detector

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    We present the results of the charge ratio (RR) and polarization (P0ÎŒP^{\mu}_{0}) measurements using the decay electron events collected from 2008 September to 2022 June by the Super-Kamiokande detector. Because of its underground location and long operation, we performed high precision measurements by accumulating cosmic-ray muons. We measured the muon charge ratio to be R=1.32±0.02R=1.32 \pm 0.02 (stat.+syst.)(\mathrm{stat.}{+}\mathrm{syst.}) at EÎŒcos⁥ΞZenith=0.7−0.2+0.3E_{\mu}\cos \theta_{\mathrm{Zenith}}=0.7^{+0.3}_{-0.2} TeV\mathrm{TeV}, where EÎŒE_{\mu} is the muon energy and ΞZenith\theta_{\mathrm{Zenith}} is the zenith angle of incoming cosmic-ray muons. This result is consistent with the Honda flux model while this suggests a tension with the πK\pi K model of 1.9σ1.9\sigma. We also measured the muon polarization at the production location to be P0ÎŒ=0.52±0.02P^{\mu}_{0}=0.52 \pm 0.02 (stat.+syst.)(\mathrm{stat.}{+}\mathrm{syst.}) at the muon momentum of 0.9−0.1+0.60.9^{+0.6}_{-0.1} TeV/c\mathrm{TeV}/c at the surface of the mountain; this also suggests a tension with the Honda flux model of 1.5σ1.5\sigma. This is the most precise measurement ever to experimentally determine the cosmic-ray muon polarization near 1 TeV/c1~\mathrm{TeV}/c. These measurement results are useful to improve the atmospheric neutrino simulations.Comment: 29 pages, 45 figure
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