84 research outputs found
Dependence of Biocatalysis on D/H Ratio: Possible Fundamental Differences for High-Level Biological Taxons
No full textThe kinetics of biological reactions depends on the deuterium/protium (D/H) ratio in water. In this work, we describe the kinetic model of biocatalytic reactions in living organisms depending on the D/H ratio. We show that a change in the lifetime or other characteristics of the vital activity of some organisms in response to a decrease or increase in the content of deuterium in the environment can be a sign of a difference in taxons. For animals—this is a curve with saturation according to the Gauss’s principle, for plants—it is the Poisson dependence, for bacteria a weakly saturated curve with a slight reaction to the deuterium/protium ratio toward increasing deuterium. The biological activity of the aquatic environment with reduced, elevated, and natural concentrations of deuterium is considered. The results of the study are presented in different vital indicators of some taxons: the bacteria kingdom—the colony forming units (CFU) index (Escherichia coli); animals—the activation energy of the death of ciliates (Spirostomum ambiguum), embryogenesis of fish (Brachydanio rerio); plants—germination and accumulation of trace elements Callisia fragrans L., sprouting of gametophores and peptidomics of moss Physcomitrella patens. It was found that many organisms change their metabolism and activity, responding to both high and low concentrations of deuterium in water. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
The Large Enriched Germanium Experiment for Neutrinoless Double Beta Decay (LEGEND)
No full textThe observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ∼0.1 count /(FWHM·t·yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results
ХИРУРГИЧЕСКОЕ ЛЕЧЕНИЕ ДОБРОКАЧЕСТВЕННЫХ И ЗЛОКАЧЕСТВЕННЫХ ОПУХОЛЕЙ СЕРДЦА И СРЕДОСТЕНИЯ У ДЕТЕЙ
No full textSUMMARY. Authors operated on 24 children with tumors of the heart and mediastinum. Analysis of the results showed that a third of patients with tumors of the thymus has had a rapid malignancy. This fact allows to conclude about the necessity of the surgery soon after the detection of tumors, despite the absence of clinical signs of the chest organs lesion. РЕЗЮМЕ. Были прооперированы 24 ребенка с новообразованиями сердца и средостения. Анализ полученных результатов показал, что у трети больных с опухолями вилочковой железы отмечается их быстрое озлокачествление. Указанное обстоятельство позволяет прийти к заключению о необходимости выполнения операции вскоре после выявления новообразования, несмотря на отсутствие клинических признаков, свидетельствующих о поражении органов грудной клетки.
First results of GERDA Phase II and consistency with background models
No full textThe GERDA (GERmanium Detector Array) is an experiment for the search of neutrinoless double beta decay (0v beta) in Ge-76, located at Laboratori Nazionali del Gran Sasso of INFN (Italy). GERDA operates bare high purity germanium detectors submersed in liquid Argon (LAr). Phase II of data-taking started in Dec 2015 and is currently ongoing. In Phase II 35 kg of germanium detectors enriched in Ge-76 including thirty newly produced Broad Energy Germanium (BEGe) detectors is operating to reach an exposure of 100 kg.yr within about 3 years data taking. The design goal of Phase II is to reduce the background by one order of magnitude to get the sensitivity for T-1/2(0v) = O(10(26)) yr. To achieve the necessary background reduction, the setup was complemented with LAr veto. Analysis of the background spectrum of Phase II demonstrates consistency with the background models. Furthermore Ra-226 and Th-232 contamination levels consistent with screening results. In the first Phase II data release we found no hint for a Ov beta beta decay signal and place a limit of this process T-1/2(0v) > 5.3.10(25) yr (90% C.L., sensitivity 4.0.10(25) yr). First results of GERDA Phase II will be presented
GERDA results and the future perspectives for the neutrinoless double beta decay search using76Ge
No full textThe GERmanium Detector Array (GERDA) is a low background experiment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN designed to search for the rare neutrinoless double beta decay (0 nu beta beta) of Ge-76. In the first phase (Phase I) of the experiment, high purity germanium diodes were operated in a "bare" mode and immersed in liquid argon. The overall background level of 10(-2) cts/(keV . kg . yr) was a factor of ten better than those of its predecessors. No signal was found and a lower limit was set on the half-life for the 0 nu beta beta decay of Ge-76 T-1/2(0 nu) > 2.1 x 10(25) yr (90% CL), while the corresponding median sensitivity was 2.4 x 10(25) yr (90% CL). A second phase (Phase II) started at the end of 2015 after a major upgrade. Thanks to the increased detector mass and performance of the enriched germanium diodes and due to the introduction of liquid argon instrumentation techniques, it was possible to reduce the background down to 10(-3) cts/(keV . kg . yr). After analyzing 23.2 kg . yr of these new data no signal was seen. Combining these with the data from Phase I a stronger half-life limit of the Ge-76 0 nu beta beta decay was obtained: T-1/2(0 nu) > 8.0 x 10(25) yr (90% CL), reaching a sensitivity of 5.8 x 10(25) yr (90% CL). Phase II will continue for the collection of an exposure of 100 kg . yr. If no signal is found by then the GERDA sensitivity will have reached 1.4 x 10(26) yr for setting a 90% CL. limit. After the end of GERDA Phase II, the flagship experiment for the search of 0 nu beta beta decay of Ge-76 will be LEGEND. LEGEND experiment is foreseen to deploy up to 1-ton of Ge-76. After ten years of data taking, it will reach a sensitivity beyond 10(28) yr, and hence fully cover the inverted hierarchy region
Gerda phase II: Search for neutrinoless double beta decay
No full textThe GERDA (GERmanium Detector Array) experiment, located at the Laboratori Nazionali del Gran Sasso, is searching for neutrinoless double beta (0νββ) decay of 76 Ge. Since the end of 2015, in Phase II of the experiment, 35 kg of enriched high-purity germanium detectors are operated in liquid argon, that serves as cooling for the detectors as well as active shield against external radiation. The aim is a sensitivity on the 0νββ decay half-life larger than 10 26 yr with about 100 kg·yr exposure and a background level of about 10 −3 cts/(keV·kg·yr). An overview of the analysis of the data collected so far is presented with an emphasis on the background rejection techniques and their performance together with the half-life limit
Search for exotic physics in double-β decays with GERDA Phase II
No full textA search for Beyond the Standard Model double-beta decay modes of 76Ge has been performed with data collected during the Phase II of the GERmanium Detector Array (Gerda) experiment, located at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Improved limits on the decays involving Majorons have been obtained, compared to previous experiments with 76Ge, with half-life values on the order of 10^23 yr. For the first time with 76Ge, limits on Lorentz invariance violation effects in double-beta decay have been obtained.The isotropic coefficient °a(3)_of , which embeds Lorentz violation in double-beta decay, has been
constrained at the order of 10^(−6) GeV. We also set the first experimental limits on the search for light exotic fermions in double-beta decay, including sterile neutrinos
Erratum: First Search for Bosonic Superweakly Interacting Massive Particles with Masses up to 1 MeV / c2 with GERDA (Physical Review Letters (2020) 125 (011801) DOI: 10.1103/PhysRevLett.125.011801)
No full textBecause of an incorrect evaluation of Eqs. (1) and (2), the upper limits on the coupling strengths gae and a'/a of pseudoscalar and vector bosonic superweakly interacting massive particles (super-WIMPs) deduced from the GERDA data (blue curves in Fig. 3) are incorrect. The corrected constraints are shown in the new Fig. 3 below. Depending on the particle mass, the correction has worsened the limits for gae by a factor between 1.8 and 1.9, and for a'/a by a factor between 3.3 and 3.6. As to the coupling strengths quoted on page 011801-5 for the mass of 150 keV / c 2 , the limit at 90% credible interval (C.I.) increases for gae from gae (Formula Presented)
First Search for Bosonic Superweakly Interacting Massive Particles with Masses up to 1 MeV/c² with GERDA
No full textWe present the first search for bosonic superweakly interacting massive particles (super-WIMPs) as keV-scale dark matter candidates performed with the GERDA experiment. GERDA is a neutrinoless double-β decay experiment which operates high-purity germanium detectors enriched in 76^{Ge} in an ultralow 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 to 1 MeV/c². 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 have been set. As an example, at a mass of 150 keV/c² the most stringent direct limits on the dimensionless couplings of axionlike particles and dark photons to electrons of g_{ae} <
3×10^{−12} and α′/α < 6.5×10^{-24} at 90% credible interval, respectively, were obtained
Searching for neutrinoless double beta decay with GERDA
No full textThe GERmanium Detector Array (Gerda) experiment located at the INFN Gran Sasso Laboratory (Italy), is looking for the neutrinoless double beta decay of 76Ge, by using high-purity germanium detectors made from isotopically enriched material. The combination of the novel experimental design, the careful material selection for radio-purity and the active/passive shielding techniques result in a very low residual background at the Q-value of the decay, about 10-3 cts/(keV-kg-yr). This makes GERDA the first experiment in the field to be background-free for the complete design exposure of 100 kg-yr. A search for neutrinoless double beta decay was performed with a total exposure of 46.7 kg-yr: 23.2 kg-yr come from the second phase (Phase II) of the experiment, in which the background is reduced by about a factor of ten with respect to the previous phase. The analysis presented in this paper includes 12.4 kg-yr of new Phase II data. No evidence for a possible signal is found: The lower limit for the half-life of 76Ge is 8.0 • 1025 yr at 90% CL. The experimental median sensitivity is 5.8 • 1025 yr. The experiment is currently taking data. As it is running in a background-free regime, its sensitivity grows linearly with exposure and it is expected to surpass 1026 yr within 2018
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