13,651 research outputs found

    The reactor antineutrino anomaly and low energy threshold neutrino experiments

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    Short distance reactor antineutrino experiments measure an antineutrino spectrum a few percent lower than expected from theoretical predictions. In this work we study the potential of low energy threshold reactor experiments in the context of a light sterile neutrino signal. We discuss the perspectives of the recently detected coherent elastic neutrino-nucleus scattering in future reactor antineutrino experiments. We find that the expectations to improve the current constraints on the mixing with sterile neutrinos are promising. We also analyse the measurements of antineutrino scattering off electrons from short distance reactor experiments. In this case, the statistics is not competitive with inverse beta decay experiments, although future experiments might play a role when compare it with the Gallium anomaly.Comment: 9 pages, 6 figures, 1 table, matches published versio

    A long-range and long-life telemetry data-acquisition system for heart rate and multiple body temperatures from free-ranging animals

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    The system includes an implantable transmitter, external receiver-retransmitter collar, and a microprocessor-controlled demodulator. The size of the implant is suitable for animals with body weights of a few kilograms or more; further size reduction of the implant is possible. The ECG is sensed by electrodes designed for internal telemetry and to reduce movement artifacts. The R-wave characteristics are then specifically selected to trigger a short radio frequency pulse. Temperatures are sensed at desired locations by thermistors and then, based on a heartbeat counter, transmitted intermittently via pulse interval modulation. This modulation scheme includes first and last calibration intervals for a reference by ratios with the temperature intervals to achieve good accuracy even over long periods. Pulse duration and pulse sequencing are used to discriminate between heart rate and temperature pulses as well as RF interference

    A non-resonant dark-side solution to the solar neutrino problem

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    We re-analyse spin-flavour precession solutions to the solar neutrino problem in the light of the recent SNO CC result as well as the 1258--day Super-Kamiokande data and the upper limit on solar anti-neutrinos. In a self-consistent magneto-hydrodynamics approach the resulting scheme has only 3 effective parameters: Δm2\Delta m^2, μB\mu B_\perp and the neutrino mixing angle θ\theta. We show how a rates-only analysis for fixed μB\mu B_\perp slightly favours spin-flavour precession (SFP) solutions over oscillations (OSC). In addition to the resonant solution (RSFP for short), there is a new non-resonant solution (NRSFP) in the ``dark-side''. Both RSFP and NRSFP lead to flat recoil energy spectra in excellent agreement with the latest SuperKamiokande data. We also show that in the presence of a neutrino transition magnetic moment of 101110^{-11} Bohr magneton, a magnetic field of 80 KGauss eliminates all large mixing solutions other than the so-called LMA solution.Comment: 12 pages, 3 postscript figures, using elsart.cls. Published versio

    Is Brazil really a catholic country? What opinions about abortion, sex between individuals who are not married to each other, and homosexuality say about the meaning of catholicism in three Brazilian cities

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    The idea of being a Catholic country is quite widespread throughout the nation. What does it mean to be Catholic in Brazil? Do Catholics follow the Catholic Doctrine? The objective of this paper is to investigate the relationship between religion and religious involvement (measured by religious affiliation and service attendance) and opinions about abortion, sex between individuals who are not married to each other, and homosexuality in São Paulo, Porto Alegre, and Recife. Data come from the survey “Spirit and Power: A 10-Country Survey of Pentecostals,” carried out in 2006. Results suggest that Brazilian Catholics are a very heterogeneous group with respect to opinions about abortion and sex between individuals who are not married to each other. In addition, service attendance among Catholics and those opinions are strongly correlated, except for the case of homosexuality, a topic which Catholics tend to have the same opinions about, irrespective of their religious involvement. Committed Protestants are, by far and away, the most conservative group.Brazil

    Periodically rippled graphene: growth and spatially resolved electronic structure

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    We studied the growth of an epitaxial graphene monolayer on Ru(0001). The graphene monolayer covers uniformly the Ru substrate over lateral distances larger than several microns reproducing the structural defects of the Ru substrate. The graphene is rippled with a periodicity dictated by the difference in lattice parameter between C and Ru. The theoretical model predict inhomogeneities in the electronic structure. This is confirmed by measurements in real space by means of scanning tunnelling spectroscopy. We observe electron pockets at the higher parts of the ripples.Comment: 5 page

    Direct absorption imaging of ultracold polar molecules

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    We demonstrate a scheme for direct absorption imaging of an ultracold ground-state polar molecular gas near quantum degeneracy. A challenge in imaging molecules is the lack of closed optical cycling transitions. Our technique relies on photon shot-noise limited absorption imaging on a strong bound-bound molecular transition. We present a systematic characterization of this imaging technique. Using this technique combined with time-of-flight (TOF) expansion, we demonstrate the capability to determine momentum and spatial distributions for the molecular gas. We anticipate that this imaging technique will be a powerful tool for studying molecular quantum gases.Comment: 4 pages, 4 figure

    Gravity-driven instability in a spherical Hele-Shaw cell

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    A pair of concentric spheres separated by a small gap form a spherical Hele-Shaw cell. In this cell an interfacial instability arises when two immiscible fluids flow. We derive the equation of motion for the interface perturbation amplitudes, including both pressure and gravity drivings, using a mode coupling approach. Linear stability analysis shows that mode growth rates depend upon interface perimeter and gravitational force. Mode coupling analysis reveals the formation of fingering structures presenting a tendency toward finger tip-sharpening.Comment: 13 pages, 4 ps figures, RevTex, to appear in Physical Review

    Mimicking diffuse supernova antineutrinos with the Sun as a source

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    Measuring the electron antineutrino component of the cosmic diffuse supernova neutrino background (DSNB) is the next ambitious goal for low-energy neutrino astronomy. The largest flux is expected in the lowest accessible energy bin. However, for E < 15 MeV a possible signal can be mimicked by a solar electron antineutrino flux that originates from the usual 8B neutrinos by spin-flavor oscillations. We show that such an interpretation is possible within the allowed range of neutrino electromagnetic transition moments and solar turbulent field strengths and distributions. Therefore, an unambiguous detection of the DSNB requires a significant number of events at E > 15 MeV.Comment: 4 pages, 1 figur

    Thinning intensity and water regime affect the impact cluster thinning has on grape quality

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    Late cluster thinning is a practice frequently used in the vineyards of semiarid regions, as it is claimed to increase total soluble solids and anthocyanin concentration. However, when performed in field conditions, it often leads to relatively inconclusive results: under some circumstances, it results in a noteworthy quality gain, whereas under other circumstances, it does not convey the improvement in quality desired.The aim of this work was to evaluate the influence of thinning intensity and vine water status on the impact cluster thinning has on grape quality. Late cluster thinning (CT) was performed at four ‘Tempranillo’ vineyards during four consecutive years. The major effects of CT were an increase in berry soluble solid, anthocyanin and phenolics concentration. The impact CT had on these parameters was related to thinning intensity, although it was more closely related to vine water status of from veraison to harvest, particularly when compared to water status during the two weeks with the lowest water availability.An estimation of the degree of water deficit that is likely to occur between veraison and harvest (considering water management guidelines of each winegrower and water reserves available in the soil or for later irrigation) has therefore to be considered in order to make proper decisions on cluster thinning, at least in the range of yield and water conditions included in this study. In rain fed or deficit irrigated vineyards water deficit alleviation might be one of the main mechanisms that make cluster thinning an effective technique to improve grape quality.
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