243 research outputs found

    Search interactive regional game as a metod of developing general competencies

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    The article presents the possibility of using regional interactive quest game as the pedagogical technology aimed to formation of the general competences of studentsВ статье рассматривается возможность использования краеведческой интерактивной игры-квеста, как педагогической технологии, направленной на формирование общих компетенций обучающихс

    Гемодинамические реакции в ходе удаления опухолей головного мозга при сочетанном использовании фентанила и альфа2-адреноагониста

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    Anesthesia including drugs that act on the opioid (fentanyl) and adrenergic (clonidine or dexmedetomidine) neuroregulatory systems, creates optimal conditions for performing brain surgery.The objective: to study the effect of combination of opioid analgesic fentanyl and alpha2-adrenoagonists on stability (reactivity) and appropriate functional activity of the circulatory system.Subjects and Methods. The study included 118 patients operated on for a brain tumor. Patients were divided into groups depending on the alpha2-adrenoagonist used, its dosage and position on the operating table.Results. In all groups, the required level of neurovegetative stabilization with stable hemodynamics was achieved at all stages of the operation. Conclusion. Studies have shown that a lower dose of dexmedetomidine versus clonidine was required to achieve a central sympatho-modulatory effect.Анестезия, включающая препараты, воздействующие на опиоидную (фентанил) и адренергическую (клонидин или дексмедетомидин) нейрорегуляторные системы, позволяет создать оптимальные условия для выполнения хирургических вмешательств на головном мозге.Цель: изучение влияния комбинации опиоидного анальгетика фентанила и альфа2-адреноагонистов на стабильность (реактивность) и целесообразную функциональную активность системы кровообращения.Материал и методы. В исследование включено 118 пациентов, оперированных по поводу опухоли головного мозга. Деление больных на группы проводили в зависимости от используемого альфа2-адреноагониста, его дозировки и положения на операционном столе.Результаты. Во всех группах достигался необходимый уровень нейровегетативной стабилизации с устойчивой гемодинамикой на всех этапах операции.Заключение. Исследование показало, что для достижения центрального симпатомодулирующего эффекта требовалась меньшая доза дексмедетомидина, чем клонидина

    Background free search for neutrinoless double beta decay with GERDA Phase II

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    The Standard Model of particle physics cannot explain the dominance of matter over anti-matter in our Universe. In many model extensions this is a very natural consequence of neutrinos being their own anti-particles (Majorana particles) which implies that a lepton number violating radioactive decay named neutrinoless double beta (0νββ0\nu\beta\beta) decay should exist. The detection of this extremely rare hypothetical process requires utmost suppression of any kind of backgrounds. The GERDA collaboration searches for 0νββ0\nu\beta\beta decay of 76^{76}Ge (^{76}\rm{Ge} \rightarrow\,^{76}\rm{Se} + 2e^-) by operating bare detectors made from germanium with enriched 76^{76}Ge fraction in liquid argon. Here, we report on first data of GERDA Phase II. A background level of 103\approx10^{-3} cts/(keV\cdotkg\cdotyr) has been achieved which is the world-best if weighted by the narrow energy-signal region of germanium detectors. Combining Phase I and II data we find no signal and deduce a new lower limit for the half-life of 5.310255.3\cdot10^{25} yr at 90 % C.L. Our sensitivity of 4.010254.0\cdot10^{25} yr is competitive with the one of experiments with significantly larger isotope mass. GERDA is the first 0νββ0\nu\beta\beta experiment that will be background-free up to its design exposure. This progress relies on a novel active veto system, the superior germanium detector energy resolution and the improved background recognition of our new detectors. The unique discovery potential of an essentially background-free search for 0νββ0\nu\beta\beta decay motivates a larger germanium experiment with higher sensitivity.Comment: 14 pages, 9 figures, 1 table; ; data, figures and images available at http://www.mpi-hd.mpg/gerda/publi

    Characterization of 30 76^{76}Ge enriched Broad Energy Ge detectors for GERDA Phase II

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    The GERmanium Detector Array (GERDA) is a low background experiment located at the Laboratori Nazionali del Gran Sasso in Italy, which searches for neutrinoless double beta decay of 76^{76}Ge into 76^{76}Se+2e^-. GERDA has been conceived in two phases. Phase II, which started in December 2015, features several novelties including 30 new Ge detectors. These were manufactured according to the Broad Energy Germanium (BEGe) detector design that has a better background discrimination capability and energy resolution compared to formerly widely-used types. Prior to their installation, the new BEGe detectors were mounted in vacuum cryostats and characterized in detail in the HADES underground laboratory in Belgium. This paper describes the properties and the overall performance of these detectors during operation in vacuum. The characterization campaign provided not only direct input for GERDA Phase II data collection and analyses, but also allowed to study detector phenomena, detector correlations as well as to test the strength of pulse shape simulation codes.Comment: 29 pages, 18 figure

    The first search for bosonic super-WIMPs with masses up to 1 MeV/c2^2 with GERDA

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    We present the first search for bosonic super-WIMPs as keV-scale dark matter candidates performed with the GERDA experiment. GERDA is a neutrinoless double-beta decay experiment which operates high-purity germanium detectors enriched in 76^{76}Ge in an ultra-low background environment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for pseudoscalar and vector particles in the mass region from 60 keV/c2^2 to 1 MeV/c2^2. No evidence for a dark matter signal was observed, and the most stringent constraints on the couplings of super-WIMPs with masses above 120 keV/c2^2 have been set. As an example, at a mass of 150 keV/c2^2 the most stringent direct limits on the dimensionless couplings of axion-like particles and dark photons to electrons of gae<31012g_{ae} < 3 \cdot 10^{-12} and α/α<6.51024{\alpha'}/{\alpha} < 6.5 \cdot 10^{-24} at 90% credible interval, respectively, were obtained.Comment: 6 pages, 3 figures, submitted to Physical Review Letters, added list of authors, updated ref. [21

    Limits on uranium and thorium bulk content in GERDA Phase I detectors

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    Internal contaminations of 238^{238}U, 235^{235}U and 232^{232}Th in the bulk of high purity germanium detectors are potential backgrounds for experiments searching for neutrinoless double beta decay of 76^{76}Ge. The data from GERDA Phase~I have been analyzed for alpha events from the decay chain of these contaminations by looking for full decay chains and for time correlations between successive decays in the same detector. No candidate events for a full chain have been found. Upper limits on the activities in the range of a few nBq/kg for 226^{226}Ra, 227^{227}Ac and 228^{228}Th, the long-lived daughter nuclides of 238^{238}U, 235^{235}U and 232^{232}Th, respectively, have been derived. With these upper limits a background index in the energy region of interest from 226^{226}Ra and 228^{228}Th contamination is estimated which satisfies the prerequisites of a future ton scale germanium double beta decay experiment.Comment: 2 figures, 7 page

    2νββ2\nu\beta\beta decay of 76^{76}Ge into excited states with GERDA Phase I

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    Two neutrino double beta decay of 76^{76}Ge to excited states of 76^{76}Se has been studied using data from Phase I of the GERDA experiment. An array composed of up to 14 germanium detectors including detectors that have been isotopically enriched in 76^{76}Ge was deployed in liquid argon. The analysis of various possible transitions to excited final states is based on coincidence events between pairs of detectors where a de-excitation γ\gamma ray is detected in one detector and the two electrons in the other. No signal has been observed and an event counting profile likelihood analysis has been used to determine Frequentist 90\,\% C.L. bounds for three transitions: 0g.s.+21+{0^+_{\rm g.s.}-2^+_1}: T1/22ν>T^{2\nu}_{1/2}>1.61023\cdot10^{23} yr, 0g.s.+01+{0^+_{\rm g.s.}-0^+_1}: T1/22ν>T^{2\nu}_{1/2}>3.71023\cdot10^{23} yr and 0g.s.+22+{0^+_{\rm g.s.}-2^+_2}: T1/22ν>T^{2\nu}_{1/2}>2.31023\cdot10^{23} yr. These bounds are more than two orders of magnitude larger than those reported previously. Bayesian 90\,\% credibility bounds were extracted and used to exclude several models for the 0g.s.+01+{0^+_{\rm g.s.}-0^+_1} transition

    Results on ββ\beta\beta decay with emission of two neutrinos or Majorons in 76^{76}Ge from GERDA Phase I

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    A search for neutrinoless ββ\beta\beta decay processes accompanied with Majoron emission has been performed using data collected during Phase I of the GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Processes with spectral indices n = 1, 2, 3, 7 were searched for. No signals were found and lower limits of the order of 1023^{23} yr on their half-lives were derived, yielding substantially improved results compared to previous experiments with 76^{76}Ge. A new result for the half-life of the neutrino-accompanied ββ\beta\beta decay of 76^{76}Ge with significantly reduced uncertainties is also given, resulting in T1/22ν=(1.926±0.095)1021T^{2\nu}_{1/2} = (1.926 \pm 0.095)\cdot10^{21} yr.Comment: 3 Figure

    Flux Modulations seen by the Muon Veto of the GERDA Experiment

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    The GERDA experiment at LNGS of INFN is equipped with an active muon veto. The main part of the system is a water Cherenkov veto with 66~PMTs in the water tank surrounding the GERDA cryostat. The muon flux recorded by this veto shows a seasonal modulation. Two effects have been identified which are caused by secondary muons from the CNGS neutrino beam (2.2 %) and a temperature modulation of the atmosphere (1.4 %). A mean cosmic muon rate of Iμ0=(3.477±0.002stat±0.067sys)×104I^0_{\mu} = (3.477 \pm 0.002_{\textrm{stat}} \pm 0.067_{\textrm{sys}}) \times 10^{-4}/(s\cdotm2^2) was found in good agreement with other experiments at LNGS at a depth of 3500~meter water equivalent.Comment: 7 pages, 6 figure
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