Search results for "Orexin"
showing 10 items of 82 documents
Search for low-energy neutrinos from astrophysical sources with Borexino
2019
We report on searches for neutrinos and antineutrinos from astrophysical sources performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. Electron antineutrinos ($\bar{\nu}_e$) are detected in an organic liquid scintillator through the inverse $\beta$-decay reaction. In the present work we set model-independent upper limits in the energy range 1.8-16.8 MeV on neutrino fluxes from unknown sources that improve our previous results, on average, by a factor 2.5. Using the same data set, we first obtain experimental constraints on the diffuse supernova $\bar{\nu}_e$ fluxes in the previously unexplored region below 8 MeV. A search for $\bar{\nu}_e$ in the solar ne…
Borexino’s search for low-energy neutrino and antineutrino signals correlated with gamma-ray bursts
2017
International audience; A search for neutrino and antineutrino events correlated with 2350 gamma-ray bursts (GRBs) is performed with Borexino data collected between December 2007 and November 2015. No statistically significant excess over background is observed. We look for electron antineutrinos ( ν¯e ) that inverse beta decay on protons with energies from 1.8 MeV to 15 MeV and set the best limit on the neutrino fluence from GRBs below 8 MeV. The signals from neutrinos and antineutrinos from GRBs that scatter on electrons are also searched for, a detection channel made possible by the particularly radio-pure scintillator of Borexino. We obtain currently the best limits on the neutrino f…
First real–time detection of solar pp neutrinos by Borexino
2014
International audience; Solar neutrinos have been pivotal to the discovery of neutrino flavour oscillations and are a unique tool to probe the reactions that keep the Sun shine. Although most of solar neutrino components have been directly measured, the neutrinos emitted by the keystone pp reaction, in which two protons fuse to make a deuteron, have so far eluded direct detection. The Borexino experiment, an ultra-pure liquid scintillator detector running at the Laboratori Nazionali del Gran Sasso in Italy, has now filled the gap, providing the first direct real time measurement of pp neutrinos and of the solar neutrino luminosity.
Solar neutrino physics with Borexino
2018
We present the most recent solar neutrino results from the Borexino experiment at the Gran Sasso underground laboratory. In particular, refined measurements of all neutrinos produced in the {\it pp} fusion chain have been made. It is the first time that the same detector measures the entire range of solar neutrinos at once. These new data weakly favor a high-metallicity Sun. Prospects for measuring CNO solar neutrinos are also discussed.
Recent results from Borexino and the first real time measure of solar pp neutrinos
2014
International audience; The Borexino detector was built starting from 1996 in the underground hall C of Gran Sasso National Laboratory (LNGS) in Italy under about 1400 m of rock (3800 m.w.e) and it is mostly aimed to the study in real-time of the low-energy solar neutrinos.Since the beginning of data taking, in May 2007, the unprecedented detector radio-purity made the performances of the detector unique: a milestone has been very recently achieved with the measurement of solar pp neutrino flux, providing the first direct observation in real time of the key fusion reaction powering the Sun.In this contribution the most important Borexino achievements to the fields of solar, geo-neutrino and…
Investigation of insulin resistance in narcoleptic patients: dependent or independent of body mass index?
2011
Alice Engel1,2, Jana Helfrich1, Nina Manderscheid1, Petra B Musholt3, Thomas Forst3, Andreas Pfützner3, Norbert Dahmen1,21Department of Psychiatry, University of Mainz, Germany; 2Fachklinik Katzenelnbogen, Katzenelnbogen, Germany; 3IKFE, Institute for Clinical Research and Development, Mainz, GermanyBackground: Narcolepsy is a severe sleep-wake cycle disorder resulting in most cases from a lack of orexin, the energy balance-regulating hormone. Narcoleptic patients have been reported to suffer from an excess morbidity of Type 2 diabetes, even after correction for their often elevated body mass index.Methods: To explore whether narcolepsy is specifically associated with a propensity …
Seasonal Modulation of the $^7$Be Solar Neutrino Rate in Borexino
2017
We detected the seasonal modulation of the $^7$Be neutrino interaction rate with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. The period, amplitude, and phase of the observed time evolution of the signal are consistent with its solar origin, and the absence of an annual modulation is rejected at 99.99\% C.L. The data are analyzed using three methods: the sinusoidal fit, the Lomb-Scargle and the Empirical Mode Decomposition techniques, which all yield results in excellent agreement.
Appetite and Obesity
2011
Orexin (hypocretin) plays an important role in promoting wakefulness [1]. It stimulates wakefulness when injected in the cerebral ventricles, in the periventricular nucleus, dorsomedial hypothalamus, or lateral hypothalamus [2, 3]. Orexinergic neurons originate from the lateral hypothalamus and have projections to most parts of the central nervous system including the brain stem. The lack of orexin and/or orexin receptors is linked to narcolepsy [4–6].
CNO and pep solar neutrino measurements and perspectives in Borexino
2015
International audience; The detection of neutrinos emitted in the CNO reactions in the Sun is one of the ambitious goals of Borexino Phase-II. A measurement of CNO neutrinos would be a milestone in astrophysics, and would allow to solve serious issues in current solar models. A precise measurement of the rate of neutrinos from the pep reaction would allow to investigate neutrino oscillations in the MSW transition region. The pep and CNO solar neutrino physics, the measurement in Borexino Phase-I and the perspectives for the new phase are reviewed in this proceeding.
Measurement of Solar pp-neutrino flux with Borexino: results and implications
2015
International audience; Measurement of the Solar pp-neutrino flux completed the measurement of Solar neutrino fluxes from the pp-chain of reactions in Borexino experiment. The result is in agreement with the prediction of the Standard Solar Model and the MSW/LMA oscillation scenario. 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 10(5) years time scale, and sets a strong limit on the power production by the unknown energy sources in the Sun.