1,774 research outputs found

    Ghosts- and Tachyon-Free Regions of the Randall-Sundrum Model Parameter Space

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    Model building within the Randall-Sundrum (RS) framework generally involves placing the Standard Model fields in the bulk. Such fields may possess non-zero values for their associated brane-localized kinetic terms (BLKTs) in addition to possible bulk mass parameters. In this paper we clearly identify the regions of the RS model parameter space where the presence of bulk mass terms and BLKTs yield a setup which is free from both ghost and tachyon instabilities. Such physically acceptable parameter space regions can then be used to construct realistic and phenomenologically viable RS models.Comment: Latex, 30 pages, 2 figure

    Ammonia Measurements and Emissions from a California Dairy Using Point and Remote Sensors

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    Ammonia (NH3) is an important trace gas species in the atmosphere that can have negative impacts on human, animal, and ecosystem health. Agriculture has been identified as the largest source of NH3, specifically livestock operations. NH3 emissions from a commercial dairy in California were investigated during June 2008. Cattle were held in open-lot pens, except for young calves in hutches with shelters. Solid manure was stored in the open-lot pens. Liquid manure from feed lanes was passed through a solids settling basin and stored in a holding pond. Passive sensors and openpath Fourier transform infrared spectrometers (OP-FTIR) were deployed around the facility to measure NH3 concentrations. Emissions from pens and the liquid manure system (LMS) were estimated using inverse modeling. Mean emission factors (EFs) for the entire facility were 140.5 ±42.5 g d-1 animal-1 from the passive sampler data and 199.2 ±22.0 g d-1 animal-1 from the OP-FTIR data, resulting in the facility’s summer emissions calculated at 265.2 ±80.2 kg d-1 and 375.4 ±27.1 kg d-1, respectively. These EFs are within the range of values reported in the literature. Both concentrations and emissions exhibited a strong diurnal cycle, peaking in the late afternoon. Total facility emissions exhibited significant positive correlations with temperature and wind speed. The findings of this study show that NH3 emissions from a commercial dairy can vary by a factor of 10 or more throughout the day, and EFs can vary by two orders of magnitude when compared to other U.S. dairies, based on literature values

    GNO Solar Neutrino Observations: Results for GNOI

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    We report the first GNO solar neutrino results for the measuring period GNOI, solar exposure time May 20, 1998 till January 12, 2000. In the present analysis, counting results for solar runs SR1 - SR19 were used till April 4, 2000. With counting completed for all but the last 3 runs (SR17 - SR19), the GNO I result is [65.8 +10.2 -9.6 (stat.) +3.4 -3.6 (syst.)]SNU (1sigma) or [65.8 + 10.7 -10.2 (incl. syst.)]SNU (1sigma) with errors combined. This may be compared to the result for Gallex(I-IV), which is [77.5 +7.6 -7.8 (incl. syst.)] SNU (1sigma). A combined result from both GNOI and Gallex(I-IV) together is [74.1 + 6.7 -6.8 (incl. syst.)] SNU (1sigma).Comment: submitted to Physics Letters B, June 2000. PACS: 26.65. +t ; 14.60 Pq. Corresponding author: [email protected] ; [email protected]

    Recent Borexino results and prospects for the near future

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    The Borexino experiment, located in the Gran Sasso National Laboratory, is an organic liquid scintillator detector conceived for the real time spectroscopy of low energy solar neutrinos. The data taking campaign phase I (2007 - 2010) has allowed the first independent measurements of 7Be, 8B and pep fluxes as well as the first measurement of anti-neutrinos from the earth. After a purification of the scintillator, Borexino is now in phase II since 2011. We review here the recent results achieved during 2013, concerning the seasonal modulation in the 7Be signal, the study of cosmogenic backgrounds and the updated measurement of geo-neutrinos. We also review the upcoming measurements from phase II data (pp, pep, CNO) and the project SOX devoted to the study of sterile neutrinos via the use of a 51Cr neutrino source and a 144Ce-144Pr antineutrino source placed in close proximity of the active material.Comment: 8 pages, 11 figures. To be published as proceedings of Rencontres de Moriond EW 201

    De Novo Missense Variants in SLC32A1 Cause a Developmental and Epileptic Encephalopathy Due to Impaired GABAergic Neurotransmission

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    Objective:Rare inherited missense variants inSLC32A1, the gene that encodes the vesicular gamma-aminobutyric acid(GABA) transporter, have recently been shown to cause genetic epilepsy with febrile seizures plus. We aimed to clarifyif de novo missense variants inSLC32A1can also cause epilepsy with impaired neurodevelopment.Methods:Using exome sequencing, we identified four individuals with a developmental and epileptic encephalopathyand de novo missense variants inSLC32A1. To assess causality, we performed functional evaluation of the identifiedvariants in a murine neuronal cell culture model.Results:The main phenotype comprises moderate-to-severe intellectual disability, infantile-onset epilepsy within thefirst 18 months of life, and a choreiform, dystonic, or dyskinetic movement disorder. In silico modeling and functionalanalyses reveal that three of these variants, which are located in helices that line the putative GABA transport pathway,result in reduced quantal size, consistent with impairedfilling of synaptic vesicles with GABA. The fourth variant,located in the vesicular gamma-aminobutyric acid N-terminus, does not affect quantal size, but increases presynapticrelease probability, leading to more severe synaptic depression during high-frequency stimulation. Thus, variants invesicular gamma-aminobutyric acid can impair GABAergic neurotransmission through at least two mechanisms, byaffecting synaptic vesiclefilling and by altering synaptic short-term plasticity.Interpretation:This work establishes de novo missense variants inSLC32A1as a novel cause of a developmental andepileptic encephalopathy

    Low-energy (anti)neutrino physics with Borexino: Neutrinos from the primary proton-proton fusion process in the Sun

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    The Sun is fueled by a series of nuclear reactions that produce the energy that makes it shine. The primary reaction is the fusion of two protons into a deuteron, a positron and a neutrino. These neutrinos constitute the vast majority of neutrinos reaching Earth, providing us with key information about what goes on at the core of our star. Several experiments have now confirmed the observation of neutrino oscillations by detecting neutrinos from secondary nuclear processes in the Sun; this is the first direct spectral measurement of the neutrinos from the keystone proton-proton fusion. This observation is a crucial step towards the completion of the spectroscopy of pp-chain neutrinos, as well as further validation of the LMA-MSW model of neutrino oscillations.Comment: Proceedings from NOW (Neutrino Oscillation Workshop) 201
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