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Kim, G. B., S. Choi, F. A. Danevich, A. Fleischmann, C. S. Kang, H. J. Kim, S. R. Kim i in. "A CaMoO4Crystal Low Temperature Detector for the AMoRE Neutrinoless Double Beta Decay Search". Advances in High Energy Physics 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/817530.
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We report the development of a CaMoO4crystal low temperature detector for the AMoRE neutrinoless double beta decay(0νββ)search experiment. The prototype detector cell was composed of a 216 g CaMoO4crystal and a metallic magnetic calorimeter. An overground measurement demonstrated FWHM resolution of 6–11 keV for full absorption gamma peaks. Pulse shape discrimination was clearly demonstrated in the phonon signals, and 7.6 σof discrimination power was found for theαandβ/γseparation. The phonon signals showed rise-times of about 1 ms. It is expected that the relatively fast rise-time will increase the rejection efficiency of two-neutrino double beta decay pile-up events which can be one of the major background sources in0νββsearches.
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Galan, J., X. Chen, H. Du, C. Fu, K. Giboni, F. Giuliani, K. Han i in. "Topological background discrimination in the PandaX-III neutrinoless double beta decay experiment". Journal of Physics G: Nuclear and Particle Physics 47, nr 4 (5.03.2020): 045108. http://dx.doi.org/10.1088/1361-6471/ab4dbe.
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Han, Tianyong, Kun Zhang, Yueyong Jiang i Hadi Rezazadeh. "Chaotic Pattern and Solitary Solutions for the (21)-Dimensional Beta-Fractional Double-Chain DNA System". Fractal and Fractional 8, nr 7 (15.07.2024): 415. http://dx.doi.org/10.3390/fractalfract8070415.
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The dynamical behavior of the double-chain deoxyribonucleic acid (DNA) system holds significant implications for advancing the understanding of DNA transmission laws in the realms of biology and medicine. This study delves into the investigation of chaos patterns and solitary wave solutions for the (2+1) Beta-fractional double-chain DNA system, employing the theory of planar dynamical systems and the method of complete discrimination system for polynomials (CDSP). The results demonstrate a diverse spectrum of solitary wave solutions, sensitivity to perturbations, and manifestations of chaotic behavior within the system. Through the utilization of the complete discrimination system for polynomials, a multitude of novel solitary wave solutions, encompassing periodic, solitary wave, and Jacobian elliptic function solutions, were systematically constructed. The influence of Beta derivatives on the solutions was elucidated through parameter comparison analysis, emphasizing the innovative nature of this study. These findings underscore the potential of this system in unraveling various biologically significant DNA transmission mechanisms.
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Yang, Jingzhe, Yang Tian, Wenhan Dai, Mingxin Yang, Lin Jiang, Jingjun Wen, Tao Xue, Ming Zeng, Yulan Li i Zhi Zeng. "A feasibility study of multi-electrode high-purity germanium detector for 76Ge neutrinoless double beta decay searching". Journal of Instrumentation 18, nr 05 (1.05.2023): P05025. http://dx.doi.org/10.1088/1748-0221/18/05/p05025.
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Abstract Experiments to search for neutrinoless double-beta (0νββ) decay of 76Ge using a high-purity germanium (HPGe) detector rely heavily on background suppression technologies to enhance their sensitivities. In this work, we proposed a pulse-shape analysis method based on a neural network (NN) and a light gradient boosting machine (lightGBM; LGB) to discriminate single-electron (background) and double-electrons (0νββ signal) events in a multi-electrode HPGe detector. In this paper, we describe a multi-electrode HPGe detector system, a data-processing system, and pulse-shape simulation procedures. We built a fully connected (FC) neural network and an LGB model to classify the single- and double-electron events. The FC network is trained with simulated single- and double-electron-induced pulses and tested in an independent dataset generated by the pulse-shape simulation. The discrimination efficiency of the FC neural network in the test set for the 0νββ double-electron events signal was 77.4%, the precision was 57.7%, and the training time was 430 min. The discrimination efficiency of LGB model was 73.1%, the precision was 64.0%, and the training time was 1.5 min. This study demonstrated that it is feasible to realize single- and double-electron discrimination on multi-electrode HPGe detectors using an FC neural network and LGB model. These results can be used as a reference for future 76Ge 0νββ experiments.
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Zatschler, S. "Pulse-shape discrimination techniques for the COBRA double beta-decay experiment at LNGS". Journal of Physics: Conference Series 888 (wrzesień 2017): 012076. http://dx.doi.org/10.1088/1742-6596/888/1/012076.
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Brodsky, Jason Philip, Samuele Sangiorgio, Michael Heffner i Tyana Stiegler. "Background discrimination for neutrinoless double beta decay in liquid xenon using Cherenkov light". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 922 (kwiecień 2019): 76–83. http://dx.doi.org/10.1016/j.nima.2018.12.057.
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MACOLINO, CARLA. "RESULTS ON NEUTRINOLESS DOUBLE-BETA DECAY FROM GERDA PHASE I". Modern Physics Letters A 29, nr 01 (7.01.2014): 1430001. http://dx.doi.org/10.1142/s0217732314300018.
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The GERmanium Detector Array, GERDA, is designed to search for neutrinoless double-beta (0νββ) decay of 76 Ge and it is installed in the Laboratori Nazionali del Gran Sasso (LNGS) of INFN, Italy. In this review, the detection principle and detector setup of GERDA are described. Also, the main physics results by GERDA Phase I, are discussed. They include the measurement of the half-life of 2νββ decay, the background decomposition of the energy spectrum and the techniques for the discrimination of the background, based on the pulse shape of the signal. In the last part of this review, the estimation of a limit on the half-life of 0νββ ([Formula: see text] at 90% C.L.) and the comparison with previous results are discussed. GERDA data from Phase I strongly disfavor the recent claim of 0νββ discovery, based on data from the Heidelberg–Moscow experiment.
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Agostini, M., A. M. Bakalyarov, M. Balata, I. Barabanov, L. Baudis, C. Bauer, E. Bellotti i in. "Searching Neutrinoless Double Beta Decay with Gerda Phase II". International Journal of Modern Physics: Conference Series 46 (styczeń 2018): 1860040. http://dx.doi.org/10.1142/s2010194518600406.
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An observation of neutrinoless double beta ([Formula: see text]) decay would allow to shed light onto the nature of neutrinos. Gerda (GERmanium Detector Array) aims to discover this process in a background-free search using [Formula: see text]Ge. The experiment is located at the Laboratori Nazionali del Gran Sasso (LNGS) of the Istituto Nazionale di Fisica Nucleare (INFN) in Italy. Bare, isotopically enriched, high purity germanium detectors are operated in liquid argon. Gerda follows a staged approach. In Phase II 35.6 kg of enriched germanium detectors are operated since December 2015. The application of active background rejection methods, such as a liquid argon scintillation light read-out and pulse shape discrimination of germanium detector signals, allows to reduce the background index to the intended level of [Formula: see text] cts/(keV⋅kg⋅yr). No evidence for the [Formula: see text] decay has been found in 23.2 kg⋅yr of Phase II data, and together with data from Phase I the up-to-date most stringent half-life limit for this process in [Formula: see text]Ge has been established, at a median sensitivity of 5.8⋅10[Formula: see text][Formula: see text]yr the 90[Formula: see text]% C.L. lower limit is 8.0⋅10[Formula: see text][Formula: see text]yr.
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Krause, P. "GERDA: Final Results and Physics Beyond Neutrinoless Double-Beta Decay". Journal of Physics: Conference Series 2156, nr 1 (1.12.2021): 012117. http://dx.doi.org/10.1088/1742-6596/2156/1/012117.
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Abstract The GERDA experiment searched for the lepton number violating neutrinoless double-beta 0υββ decay of 76 Ge. Observation of this decay would provide answers to fundamental problems in particle physics and cosmology, including the origin of neutrino masses and baryon asymmetry in the universe. The GERDA experiment achieved the most stringent lower limit on the half-life of the 0υββ decay of 1.8 • 1026 yr at 90% C.L. (which coincides with the sensitivity) by operating high-purity germanium (HPGe) detectors enriched in 76Ge submerged in liquid argon (LAr). The collaboration could achieve this breakthrough by reducing the background event rate to 5.2 • 10–4 counts/(keV kg yr) at the end-point energy. This unprecedented background index could be achieved by developing unique technologies like utilizing the scintillation light of the LAr to reject efficiently background events that deposit energy simultaneously in the HPGe detectors and in LAr, and the pulse shape discrimination which exploits specific event topologies of backgrounds and signal candidates. Due to the ultra-low background approach the GERDA data is also suited for other rare event searches beyond the 0υββ decay like the search for super-WIMPs.
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Zolotarova, A., I. C. Bandac, A. S. Barabash, V. Berest, L. Bergé, Ch Bourgeois, J. M. Calvo-Mozota i in. "The neutrinoless double beta decay CROSS experiment: demonstrator with surface sensitive bolometers". Journal of Physics: Conference Series 2156, nr 1 (1.12.2021): 012157. http://dx.doi.org/10.1088/1742-6596/2156/1/012157.
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Abstract The CROSS experiment is proposing to use a new technology of surface sensitive bolometers for low-background neutrinoless double beta decay searches. Efficient rejection of surface α and β events will allow to reach background in the region of interest below than 10−4 cnts/keV/kg/yr. The isotopes of interest, which are 130Te and 100Mo, are investigated with TeO2 and Li2MoO4 bolometers. The surface sensitivity is achieved thanks to the evaporation of thin metallic film on the crystal surface that modifies the pulse shape of near-surface events. An investigation of various pulse shape parameters was performed. The analysis shows that one of the best parameters for discrimination is the integrated area of the raw signal both for TeO2 and Li2MoO4 with Pd-Al (10 nm - 100 nm) bi-layer.
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Ieki, S., S. Asami, S. Axani, S. Futagi, K. Hosokawa, K. Ishidoshiro, T. Nakahata i K. Nakamura. "Concept of KamLAND2 DAQ system". Journal of Physics: Conference Series 2374, nr 1 (1.11.2022): 012104. http://dx.doi.org/10.1088/1742-6596/2374/1/012104.
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The KamLAND-Zen experiment is searching for neutrinoless double-beta decay of 136Xe. We are preparing for the upgrade of the KamLAND detector, KamLAND2. It is designed to improve the discrimination power of two-neutrino double-beta decay and cosmic-ray muon spallation backgrounds. Data acquisition of all neutrino events from nearby supernova is also an important issue of the KamLAND2 experiment and the data rate is a key factor to design a new DAQ system. High speed sampling will be realized with RFSoC on the front-end electronics. Data is read out from FEE to DAQ computers via 10 GbE, and FairMQ is one of the candidates for KamLAND2 DAQ software. In the KamLAND DAQ, the whole trigger system is implemented in hardware, while the KamLAND2 DAQ adopts hardware trigger for photon detection and software trigger to extract physics events. A simulation study of the software trigger is proceeding in order to detect low energy events using timing and charge information.
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Cebrián, S., T. Dafni, H. Gómez, D. C. Herrera, F. J. Iguaz, I. G. Irastorza, G. Luzón, L. Segui i A. Tomás. "Pattern recognition of136Xe double beta decay events and background discrimination in a high pressure xenon TPC". Journal of Physics G: Nuclear and Particle Physics 40, nr 12 (18.11.2013): 125203. http://dx.doi.org/10.1088/0954-3899/40/12/125203.
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Willers, M., F. v. Feilitzsch, A. Gütlein, A. Münster, J. C. Lanfranchi, L. Oberauer, W. Potzel i in. "Neganov-Luke amplified cryogenic light detectors for the background discrimination in neutrinoless double beta decay search with TeO2bolometers". Journal of Instrumentation 10, nr 03 (3.03.2015): P03003. http://dx.doi.org/10.1088/1748-0221/10/03/p03003.
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Obara, S., Y. Gando, S. Ieki, H. Ikeda, K. Ishidoshiro i R. Nakamura. "A study of self-vetoing balloon vessel for liquid-scintillator detectors". Journal of Physics: Conference Series 2374, nr 1 (1.11.2022): 012111. http://dx.doi.org/10.1088/1742-6596/2374/1/012111.
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KamLAND-Zen searches for neutrinoless double-beta decay with an ultra-pure liquid-scintillator (LS) filled with a custom-made clean nylon balloon. The primary backgrounds are radioactive impurities such as uranium and thorium series. To reduce them, we studied a self-vetoing balloon-shaped vessel for a future upgrade program, “KamLAND2-Zen”. We selected Polyethylene-Naphthalate (PEN) film which emit fluorescent light and performed the feasibility studies. Owing to its scintillation properties, 214Bi background could be identified in the KamLAND2-Zen. Moreover, thanks to the different waveforms between the LS and the PEN, we can apply the pulse-shape-discrimination for 212Bi-Po pileup background. We evaluated its background rejection efficiency as more than 90%. Resulting from these studies, it is possible to remove restrictions on fiducial volume in KamLAND2-Zen.
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Ai, P., D. Wang, G. Huang i X. Sun. "Three-dimensional convolutional neural networks for neutrinoless double-beta decay signal/background discrimination in high-pressure gaseous Time Projection Chamber". Journal of Instrumentation 13, nr 08 (16.08.2018): P08015. http://dx.doi.org/10.1088/1748-0221/13/08/p08015.
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Kim, W. T., S. C. Kim, B. Sharma, V. D. Grigorieva, J. A. Jeon, H. L. Kim, H. J. Kim i in. "An MMC-based cryogenic calorimeter with a massive sodium molybdate crystal absorber for neutrinoless double beta decay searches". Journal of Instrumentation 17, nr 04 (1.04.2022): P04004. http://dx.doi.org/10.1088/1748-0221/17/04/p04004.
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Abstract Sodium molybdate crystals are excellent scintillating target material that can be used to investigate the neutrinoless double beta decay of 100Mo. Because this material contains Na nuclei, it could also be used to clarify the contribution of Na in the controversial claim of dark matter observation by the DAMA/LIBRA experiment. Recent developments have allowed the growth of sodium molybdate crystals of several hundred grams, which makes it possible to build large scale experiments. Therefore, a cryogenic calorimeter with a crystal of significant mass, which can exploit the excellent energy resolution from thermal signals and particle identification using the scintillation signals, is highly desired. We have developed a cryogenic calorimeter with a cylindrical sodium molybdate crystal of 178 g with dimensions of 4 cm (height) × 4 cm (diameter) coupled to a metallic magnetic calorimeter (MMC). The detector was also equipped with a light detector with a thin Ge absorber to detect scintillation signals. The detector test measurements showed excellent energy resolution and particle discrimination using dual detection of heat and light signals, and thus demonstrate that the crystal is a promising tool for searching for rare phenomena events. Details of the detector development with the massive sodium molybdate crystal are discussed in this paper along with the performance results from test measurements.
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Lobasenko, A. "Reconstruction of missing data of the PandaX-III experiment TPC using neural network". Journal of Instrumentation 18, nr 08 (1.08.2023): C08011. http://dx.doi.org/10.1088/1748-0221/18/08/c08011.
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Abstract The PandaX-III is a Neutrinoless Double-Beta Decay (NLDBD) experiment which uses a Time Projection Chamber (TPC) detector with a readout plane formed of Micromegas modules, which allows reconstruction of track topology for the background discrimination as well as reconstruction of the energy of the events. In NLDBD experiments, in order to achieve the highest sensitivity to the decay, it is necessary for the detector to have a high energy resolution, the background level should be low, and techniques for background discrimination must be applied as well. In reality, inhomogeneous signal gain at each module and the presence of missing channels lead to an incorrect energy reconstruction of the events. In this work, a method based on a Convolutional Neural Networks (CNN) aiming to reconstruct the kinematics of the event from imperfect data with missing channels is presented. Preliminary results of the reconstruction of the missing data using CNN are showing an increase in detection efficiency. The detection efficiency was evaluated on the simulated data with three channels randomly chosen per Micromegas module and artificially set as missing. Direct reconstruction of the energy gives the efficiency of 78%, while after applying CNN it increases to 86%, providing a promising application of this technique.
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Bourbouli, Mara, Michael Rentzos, Anastasia Bougea, Vasiliki Zouvelou, Vasilios C. Constantinides, Ioannis Zaganas, Ioannis Evdokimidis, Elisabeth Kapaki i George P. Paraskevas. "Cerebrospinal Fluid TAR DNA-Binding Protein 43 Combined with Tau Proteins as a Candidate Biomarker for Amyotrophic Lateral Sclerosis and Frontotemporal Dementia Spectrum Disorders". Dementia and Geriatric Cognitive Disorders 44, nr 3-4 (2017): 144–52. http://dx.doi.org/10.1159/000478979.
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Background: Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are nowadays recognized as spectrum disorders with a molecular link, the TAR DNA-binding protein 43 (TDP-43), rendering it a surrogate biomarker for these disorders. Methods: We measured cerebrospinal fluid (CSF) levels of TDP-43, beta-amyloid peptide with 42 amino acids (Aβ42), total tau protein (τT), and tau protein phosphorylated at threonine 181 (τP-181) in 32 patients with ALS, 51 patients with FTD, and 17 healthy controls. Double-sandwich commercial enzyme-linked immunosorbent assays were used for measurements. Results: Both ALS and FTD patients presented with higher TDP-43 and τT levels compared to the control group. The combination of biomarkers in the form of the TDP-43 × τT / τP-181 formula achieved the best discrimination between ALS or FTD and controls, with sensitivities and specificities >0.8. Conclusion: Combined analysis of TDP-43, τT, and τP-181 in CSF may be useful for the antemortem diagnosis of ALS and FTD.
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KLAPDOR-KLEINGROTHAUS, H. V., I. V. KRIVOSHEINA i I. V. TITKOVA. "THEORETICAL DESCRIPTION OF DOUBLE BETA DECAY TRACKS IN A GERMANIUM DETECTOR AND OF THEIR DEPENDENCE ON PARTICLE AND NUCLEAR PHYSICS — A REVIEW". International Journal of Modern Physics A 21, nr 06 (10.03.2006): 1159–88. http://dx.doi.org/10.1142/s0217751x0603148x.
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In this review for the first time a theoretical description of the tracks of events of nuclear double beta decay in a large Ge detector is presented. It is obvious that in principle the shapes and sizes of these tracks — and the corresponding time structure of pulses — depend on particle physics and nuclear physics parameters such as neutrino mass, right-handed current parameters, and nuclear matrix elements. The knowledge of this dependence is of importance, since the key to probe the existence of 0νββ decay beyond observation of a signal at the Q value of the process, Qββ, is the discrimination of ββ events from background γ events (or other events), in almost any double beta decay experiment (see Refs. 2 and 3). In this review Monte-Carlo simulations of tracks of neutrino-accompanied (2νββ) and neutrinoless double beta decay (0νββ) events, and of various kinds of background processes such as multiple and other γ interactions are reported for a large Ge detector. The time history of the evolution of the individual events is followed and the sizes of the events (volumes in the detector inside which the energy of the event is released) are investigated. Effects of the angular correlations of the two electrons in ββ decay, which again depend on the above nuclear and (for 0νββ decay) particle physics parameters, are taken into account and have been calculated for this purpose for the first time on basis of the experimental half-life of 76 Ge and of realistic nuclear matrix elements. It is shown for ββ decay of 76 Ge , that 0νββ events are to a large extent separable from Compton scattering of γ events of the same energy, while double escape peaks of γ-lines show very similar behavior as 0νββ events, and in that sense can be useful for corresponding "calibration" of pulse shapes of the detector. The possibility to distinguish 0νββ events from γ events is found to be essentially independent of the particle physics parameters of the 0νββ process. A brief outlook is given on the potential of future experiments with respect to determination of the particle physics parameters 〈mν〉, 〈λ〉, 〈η〉. It is suggested, that the strategy in future 0νββ research should be, to combine confirmation of the HEIDELBERG-MOSCOW result with determination of the mechanism of the dominating decay, instead of repeating earlier experiments or ideas. The future experiment thus should not use 76 Ge or 136 Xe , but instead 124 Xe .
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Iguaz, F. J., F. Aznar, J. F. Castel, S. Cebrián, T. Dafni, J. Galán, J. G. Garza i in. "The potential of discrimination methods in a high pressure xenon TPC for the search of the neutrinoless double-beta decay of Xe-136". Journal of Physics: Conference Series 888 (wrzesień 2017): 012078. http://dx.doi.org/10.1088/1742-6596/888/1/012078.
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Budjáš, Dušan, Marik Barnabé Heider, Oleg Chkvorets, Nikita Khanbekov i Stefan Schönert. "Pulse shape discrimination studies with a Broad-Energy Germanium detector for signal identification and background suppression in the GERDA double beta decay experiment". Journal of Instrumentation 4, nr 10 (20.10.2009): P10007. http://dx.doi.org/10.1088/1748-0221/4/10/p10007.
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Ruiz, José F., Orlando Domínguez, Teresa Laín de Lera, Miguel García–Díaz, Antonio Bernad i Luis Blanco. "DNA polymerase mu, a candidate hypermutase?" Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 356, nr 1405 (29.01.2001): 99–109. http://dx.doi.org/10.1098/rstb.2000.0754.
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A novel DNA polymerase (Pol μ) has been recently identified in human cells. The amino–acid sequence of Pol μ is 42% identical to that of terminal deoxynucleotidyl transferase (TdT), a DNA–independent DNA polymerase that contributes to antigen–receptor diversity. In this paper we review the evidence supporting the role of Pol μ in somatic hypermutation of immunoglobulin genes, a T–dependent process that selectively occurs at germinal centres: (i) preferential expression in secondary lymphoid organs; (ii) expression associated to developing germinal centres; and (iii) very low base discrimination during DNA–dependent DNA polymerization by Pol μ, a mutator phenotype enormously accentuated by the presence of activating Mn 2+ ions. Moreover, its similarity to TdT, together with extrapolation to the crystal structure of DNA polymerase beta complexed (Pol β) with DNA, allows us to discuss the structural basis for the unprecedented error proneness of Pol μ, and to predict that Pol μ is structurally well suited to participate also in DNA end–filling steps occurring both during V(D)J recombination and repair of DNA double–strand breaks that are processed by non–homologous end–joining.
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Kim, W. T., S. C. Kim, B. Sharma, O. Gileva, V. D. Grigorieva, J. A. Jeon, C. H. Lee i in. "Optimization of cryogenic calorimetric detection with lithium molybdate crystals for AMoRE-II experiments". Journal of Instrumentation 17, nr 07 (1.07.2022): P07034. http://dx.doi.org/10.1088/1748-0221/17/07/p07034.
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Abstract The AMoRE collaboration is preparing for the second phase of the experiment, AMoRE-II, which will exploit a 100 kg of 100Mo isotopes to search for neutrinoless double beta decay from the isotope. Most of the 100Mo isotopes will be contained in the lithium molybdate (Li2MoO4) crystals, which will act as absorbers of cryogenic calorimeters coupled to MMC (metallic magnetic calorimeter) sensors. The detector array will have a total mass of approximately 200 kg with hundreds of detector modules. Hence, considerable effort has been taken to optimize the lithium molybdate crystal detector in terms of the detector performance and preparation procedure to build many detector modules in a reasonable schedule without compromising the detector performance. We found some critical experimental conditions to improve the energy resolution in a series of test experiments. In this paper, we discuss the effect of surface treatment and thermal link connection in improving the energy resolution from 14–15 keV to below 7 keV at 2.615 MeV, 208Tl gamma line, which is near the Q-value of the decay of 100Mo, 3.034MeV. We also report the high discrimination power for the separation of alpha particles using the simultaneous scintillation light detection with a test performed in the cryogen-free dilution refrigerator.
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Avignone, F. T., A. S. Barabash, V. Berest, L. Bergé, J. M. Calvo-Mozota, P. Carniti, M. Chapellier i in. "Development of large-volume 130TeO2 bolometers for the CROSS 2β decay search experiment". Journal of Instrumentation 19, nr 09 (1.09.2024): P09013. http://dx.doi.org/10.1088/1748-0221/19/09/p09013.
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Abstract We report on the development of thermal detectors based on large-size tellurium dioxide crystals (45 × 45 × 45 mm), containing tellurium enriched in 130Te to about 91%, for the CROSS double-beta decay experiment. A powder used for the crystals growth was additionally purified by the directional solidification method, resulting in the reduction of the concentration of impurities by a factor 10, to a few ppm of the total concentration of residual elements (the main impurity is Fe). The purest part of the ingot (the first ∼ 200 mm, about 80% of the total length of the cylindrical part of the ingot) was determined by scanning segregation profiles of impurities and used for the 130TeO2 powder production with no evidence of re-contamination. The crystal growth was verified with precursors produced from a powder with natural Te isotopic composition, and two small-size (20 × 20 × 10 mm) samples were tested at a sea-level laboratory showing high bolometric and spectrometric performance together with acceptable 210Po content (below 10 mBq/kg). This growth method was then applied for the production of six large cubic 130TeO2 crystals and 4 of them were taken randomly to be characterized at the Canfranc underground laboratory, in the CROSS-dedicated low-background cryogenic facility. Two 130TeO2 samples were coated with a thin, 𝒪(100 nm), metal film in form of Al layer (on 4 sides) or AlPd grid (on a single side) to investigate the possibility to tag surface events by pulse-shape discrimination. Similarly to the small natural precursors, large-volume 130TeO2 bolometers show high performance and even better internal purity (210Po activity ∼ 1 mBq/kg, while activities of 228Th and 226Ra are below 0.01 mBq/kg), satisfying requirements for the CROSS and, potentially, next-generation experiments.
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Vivekanand, P. Verma i K. Chaturvedi. "Limits on Effective Masses of Light and Heavy Majorana Neutrinos for Positron Emitting Modes of Double Beta Decay". Journal of Scientific Research 14, nr 1 (1.01.2022): 1–10. http://dx.doi.org/10.3329/jsr.v14i1.50390.
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Double beta decay is a rare weak interaction process in which two identical nucleons inside the nucleus decay with or without the emission of neutrinos. If the neutrinoless double beta decay is observed, the (e+DBD) processes will play a crucial role in discriminating the finer issues like the dominance of Majorana neutrino mass or the right-handed current. In the present work, we have obtained the limits on the effective mass of light and heavy Majorana neutrinos for the electron-positron conversion and double positron-emitting modes of 96Ru, 106Cd, 124Xe, and 130Ba isotopes, using the nuclear transition matrix elements NTMEs M(0ν) and M(0N) for light and heavy Majorana neutrinos obtained in projected Hartree-Fock Bogoliubov (PHFB) model. The predicted half-lives and corresponding extracted limits on heavy neutrino mass <MN> is discussed. We have also calculated nuclear sensitivities ξ(0ν) and ξ(0N) due to the light and heavy neutrino exchange, respectively. Finally, the mass limits are obtained using various phase space factors (PSF), and the effect of this PSF on mass limits is discussed.
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Francis, Ng K., i Ankur Nath. "The Effects of Majorana Phases in Estimating the Masses of Neutrinos". International Journal of Modern Physics: Conference Series 47 (styczeń 2018): 1860100. http://dx.doi.org/10.1142/s201019451860100x.
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Majorana CP violating phases coming from heavy right-handed Majorana mass matrices([Formula: see text]) are considered to estimate the masses of neutrinos. The effects of phases on quasi-degenerate neutrinos mass matrix obeying [Formula: see text] symmetry predicts the results consistent with observations for (i) solar mixing angle([Formula: see text]) below TBM, (ii) absolute neutrino mass parameters[[Formula: see text]] in neutrinoless double beta([Formula: see text]) decay, and (iii) cosmological upper bound [Formula: see text]. Analysis is carried out through parameterization of light left-handed Majorana neutrino matrices ([Formula: see text]) using only two unknown parameters ([Formula: see text]) within [Formula: see text] symmetry. We consider the charge lepton and up quark matrices as diagonal form of Dirac neutrino mass matrix ([Formula: see text]), and [Formula: see text] are generated using [Formula: see text] through inversion of Type-I seesaw formula. The analysis shows that the masses of neutrinos are in agreement with the upper bound from cosmology and neutrinoless double beta decay. The results presented in this article will have important implications in discriminating the neutrinos mass models.
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Lautridou, Pascal. "An R&D program for the research of 2β0ν decay with a SPC". Journal of Physics: Conference Series 2502, nr 1 (1.05.2023): 012006. http://dx.doi.org/10.1088/1742-6596/2502/1/012006.
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Abstract The objective of the R2D2 R&D is to test the concept of a spherical proportional counter (SPC) for the search of the neutrinoless double beta decay (2β0ν). For this, we built a small prototype (40 cm in diameter), which was filled with an argon-based gas mixture at pressures up to 1.1 bar, and irradiated with a 210Po alpha source. We report on results obtained in terms of directional, volume, and energy responses. We performed time measurements by combining the charge readout from the SPC with the light detection provided by a SiPM. We also studied the possibilities of localizing tracks in the detector and of discriminating multiple tracks.
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Massmann, Alexander, i Keith R. Fox. "Modifying Our Genes: Theology, Science and “Playing God”". Perspectives on Science and Christian Faith 75, nr 3 (grudzień 2023): 201–3. http://dx.doi.org/10.56315/pscf12-23massmann.
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MODIFYING OUR GENES: Theology, Science and "Playing God" by Alexander Massmann and Keith R. Fox. London, UK: SCM Press, 2021. vii + 151 pages. Paperback; $21.49. ISBN: 9780334059530. *Modifying Our Genes: Theology, Science and "Playing God" is a thought-provoking exploration of the ethical, theological, and scientific implications surrounding human genome editing. Written by Alexander Massmann, a theologian, and Keith R. Fox, a scientist, this book examines the topic clearly and is comprehensible even for those without a background in genetics or bioethics. While their ethical considerations are biblically based, they also draw upon arguments in philosophy and other fields to facilitate a more inclusive debate. *Chapter 1 discusses the overall significance of genome editing using CRISPR-Cas9, and lays out key themes discussed in subsequent chapters. Developed by Emmanuelle Charpentier and Jennifer Doudna just over a decade ago, CRISPR-Cas9 greatly simplifies the process of making alterations at precise locations in DNA compared to previous methods. While this molecular tool can be used to genetically modify body cells in children or adults (somatic gene editing), these alterations are not passed on to future generations, unlike alterations to human embryos (germline gene editing), which are of greater ethical concern to Massmann and Fox. *For the benefit of the layperson, chapter 2 provides a basic primer in genetics and the CRISPR-Cas9 method. The authors note that over 10,000 different inherited human diseases are caused by a defect in a single gene and would be the most feasible targets for therapeutic genome editing. However, many human traits and disorders result from a complex interaction between multiple genes and are less -amenable to genetic intervention. Moreover, Massmann and Fox point out that environmental, lifestyle, and developmental factors work together with genes to determine human traits and diseases--we are not simply a "product" of our genes alone! They describe, in simple terms, how the Cas9 protein uses a guide RNA to precisely direct the position of a double-stranded cut in DNA, and how repair of the cut by nonhomologous end-joining leads to short deletions or insertions that usually inactivate the gene. Repair of the cut by homologous recombination is less clearly explained in this book. The authors also do not mention base editing or prime editing at all. These variations of CRISPR-Cas9 technology, reported in peer-reviewed journals by 2019, correct mutated copies of genes without making double-stranded cuts in DNA or requiring a corrective donor DNA molecule. *In chapter 3, the authors briefly summarize the successes so far with therapeutic genome editing in children or adults, especially for genetic disorders involving the blood, such as sickle cell anemia, beta thalassemia, and leukemia. For disorders involving other body tissues and organs, they note the challenge that must be overcome in delivering gene editing tools to enough cells to achieve a therapeutic effect. The problem with delivery is greatly reduced, however, if genome editing is done on embryos. *While safety concerns tend to dominate many ethical analyses of genome editing, especially for germline gene editing, that is not true for Massmann and Fox. The authors acknowledge that technological improvements may eventually reduce the error rate in the editing process to an acceptable level. They reject germline gene editing on other grounds, even for medical purposes. Among their most compelling arguments is that using this technology to edit out "debilitating" characteristics could cause greater stigmatization and marginalization in our society for people with disabilities or serious genetic disorders. In support of this concern, the authors cite negative attitudes toward babies with Down syndrome in Denmark where free prenatal tests are available and 95% of babies diagnosed with Down's are aborted. From a Christian perspective, they invoke Matthew 25:31-46 in saying that those who are left behind by medical progress, or who are excluded, or who are looked down upon are among "the least of these" and are worthy of our care. On page 64, they call for a renewed effort to include people in society with chronic illnesses and disabilities as we continue to make progress in somatic gene editing. *Massmann and Fox maintain that genetically modifying human embryos carrying a disease mutation is unnecessary if healthy embryos can be identified by preimplantation genetic diagnosis (PGD) following in vitro fertilization, even if it leads to an increase in the number of unused and discarded human embryos. Some may view their preference for PGD over germline gene editing as inconsistent with their concern about stigmatizing those with disabilities, especially since it results in the destruction rather than the "healing" of some human embryos. All they could say in response to that criticism is that both PGD and genome editing require embryo selection. They advocate limiting the use of PGD to medical considerations, preferably to avoid the birth of a child with a very severe disease. This is consistent with their view (p. 63) that "a meaningful and fulfilled life will be made more difficult by conditions that cause significant and persistent pain." On page 62, they suggest that it may be possible to select sperm without a harmful mutation before in vitro fertilization to increase the number of eligible healthy embryos for implantation. However, they give no explanation for how this selection might be done without destroying the sperm cells in the process, and no reference is provided. *In chapter 4, Massmann and Fox consider the possible use of somatic or germline gene editing for introducing nonmedical enhancements, such as improved athletic ability, memory, and life span. They argue that genetic enhancements could exacerbate social inequalities for underprivileged people, leading to diminished social participation and reduced political or economic opportunities. They challenge the assumption that greater physical and mental capabilities will produce more fulfilling lives and reiterate their concern that it could lead to discrimination against people living with genetic diseases or disabilities. The authors also question whether it is appropriate for parents to choose enhancements for their children. Would children become more like commodities than precious gifts, subject to our own design or will? Considering these arguments, the authors suggest limiting genome editing to medical and therapeutic procedures, which they define as any intervention that restores or preserves the function of an organ. *Chapter 5 focuses on the history of eugenics around the world. Massmann and Fox note that the murder of about 200,000 disabled people by the Nazis was not motivated by considerations of race or concerns that future generations might inherit a genetic impairment. Instead, it was motivated by economic considerations (the cost of care for the disabled and their lack of productivity) and an "ableist" mentality that emphasizes independence and physical functioning while marginalizing dependence, weakness, and vulnerability. The authors express concern that far-reaching genome modifications, especially genome enhancements, will reinforce an ableist mentality in our society, leading to antidisability prejudice. *In the final chapter (chap. 6), Massmann and Fox consider human dignity, arising from our creation "in the image of God," and its implications for advancements in biotechnology. They maintain that human dignity is more than just a respect for personal autonomy; it also includes a moral call to work for the benefit of others and to take care of our own bodies and personal health. The authors assert that society should not allow technologies, such as genetic enhancements, to be marketed freely if there is a significant health risk, even if individuals have given informed consent. On the other hand, they note that as God's image-bearers we can use science to "tame the destructive forces and to restore order where chaos threatens life" (p. 130). The authors conclude that as we employ new technologies to overcome disease and infirmity, we must do so in a way that respects the dignity of patients as well as of the scientists who develop the technologies and the caregivers who administer them. We must also ensure that our zeal for increased levels of function does not lead to the exclusion of those with disabilities. *Reviewed by Brian T. Greuel, Emeritus Professor of Biology, John Brown University, Siloam Springs, AR 72761.
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Deye, Nicolas, Amelie Le Gouge, Bruno François, Camille Chenevier-Gobeaux, Thomas Daix, Hamid Merdji, Alain Cariou i in. "Can Biomarkers Correctly Predict Ventilator-associated Pneumonia in Patients Treated With Targeted Temperature Management After Cardiac Arrest? An Exploratory Study of the Multicenter Randomized Antibiotic (ANTHARTIC) Study". Critical Care Explorations 6, nr 7 (1.07.2024): e1104. http://dx.doi.org/10.1097/cce.0000000000001104.
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IMPORTANCE: Ventilator-associated pneumonia (VAP) frequently occurs in patients with cardiac arrest. Diagnosis of VAP after cardiac arrest remains challenging, while the use of current biomarkers such as C-reactive protein (CRP) or procalcitonin (PCT) is debated. OBJECTIVES: To evaluate biomarkers’ impact in helping VAP diagnosis after cardiac arrest. DESIGN, SETTING, AND PARTICIPANTS: This is a prospective ancillary study of the randomized, multicenter, double-blind placebo-controlled ANtibiotherapy during Therapeutic HypothermiA to pRevenT Infectious Complications (ANTHARTIC) trial evaluating the impact of antibiotic prophylaxis to prevent VAP in out-of-hospital patients with cardiac arrest secondary to shockable rhythm and treated with therapeutic hypothermia. An adjudication committee blindly evaluated VAP according to predefined clinical, radiologic, and microbiological criteria. All patients with available biomarker(s), sample(s), and consent approval were included. MAIN OUTCOMES AND MEASURES: The main endpoint was to evaluate the ability of biomarkers to correctly diagnose and predict VAP within 48 hours after sampling. The secondary endpoint was to study the combination of two biomarkers in discriminating VAP. Blood samples were collected at baseline on day 3. Routine and exploratory panel of inflammatory biomarkers measurements were blindly performed. Analyses were adjusted on the randomization group. RESULTS: Among 161 patients of the ANTHARTIC trial with available biological sample(s), patients with VAP (n = 33) had higher body mass index and Acute Physiology and Chronic Health Evaluation II score, more unwitnessed cardiac arrest, more catecholamines, and experienced more prolonged therapeutic hypothermia duration than patients without VAP (n = 121). In univariate analyses, biomarkers significantly associated with VAP and showing an area under the curve (AUC) greater than 0.70 were CRP (AUC = 0.76), interleukin (IL) 17A and 17C (IL17C) (0.74), macrophage colony-stimulating factor 1 (0.73), PCT (0.72), and vascular endothelial growth factor A (VEGF-A) (0.71). Multivariate analysis combining novel biomarkers revealed several pairs with p value of less than 0.001 and odds ratio greater than 1: VEGF-A + IL12 subunit beta (IL12B), Fms-related tyrosine kinase 3 ligands (Flt3L) + C–C chemokine 20 (CCL20), Flt3L + IL17A, Flt3L + IL6, STAM-binding protein (STAMBP) + CCL20, STAMBP + IL6, CCL20 + 4EBP1, CCL20 + caspase-8 (CASP8), IL6 + 4EBP1, and IL6 + CASP8. Best AUCs were observed for CRP + IL6 (0.79), CRP + CCL20 (0.78), CRP + IL17A, and CRP + IL17C. CONCLUSIONS AND RELEVANCE: Our exploratory study shows that specific biomarkers, especially CRP combined with IL6, could help to better diagnose or predict early VAP occurrence in cardiac arrest patients.
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Bryant, Barbara J., Julie A. Hopkins i Susan F. Leitman. "Evaluation of Low Mean Corpuscular Volume in an Apheresis Donor Population." Blood 108, nr 11 (16.11.2006): 4136. http://dx.doi.org/10.1182/blood.v108.11.4136.4136.
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Abstract Donors of apheresis blood components are routinely evaluated with a complete blood count (CBC) at the time of each donation. In otherwise healthy donors, recurrent low mean corpuscular volume (MCV) values (< 80 fL) in the presence of an acceptable hemoglobin (≥ 12.5 gm/dL) could be due to iron deficiency or to an hemoglobinopathy, such as alpha thalassemia trait or a beta chain variant trait. Iron deficiency in repeat blood donors may warrant treatment with oral iron supplementation, whereas donors with hemoglobinopathies in the absence of iron deficiency do not need treatment. Pre-donation samples for CBC (Cell-Dyn 4000, Abbott) were obtained from all apheresis donors donating platelets, plasma, granulocytes, lymphocytes, and monocytes. MCV values <80 fL were electronically flagged via a donor database module for review by medical staff. Donors with MCV ≤ 80 fL on two or more occasions were evaluated for iron deficiency and the presence of hemoglobinopathies. CBC, ferritin, serum iron, transferrin, percent transferrin saturation, and hemoglobin electrophoresis were performed at the time of a subsequent donation. Iron deficiency was defined as values below the reference range for ferritin or transferrin saturation. Alpha thalassemia trait was presumed if the red blood cell count was elevated, no variant hemoglobins were detected by electrophoresis, and the ferritin, percent transferrin saturation, serum iron, and transferrin levels were all within normal ranges. In a one-year period, 25 of 1333 healthy apheresis donors had a low MCV on more than one occasion. Donors with low MCV were more likely to be African American (AA) (12 of 25, 48%) or Asian (2 of 25, 8%) compared with donors without a low MCV (AA 193 of 1308, 15%; Asian 37 of 1308, 3%). Iron deficiency was present in 60% (15 of 25) of the low-MCV donors: 36% (9) had isolated iron deficiency, 20% (5) had iron deficiency with probable alpha thalassemia trait, and 4% (1) had hemoglobin C trait with coexistent iron deficiency. Hemoglobinopathy without concomitant iron deficiency was found in 40% (10 of 25) of the low-MCV donors and included 24% (6) with presumed alpha thalassemia trait, 4% (1) with hemoglobin S trait and single gene deletion alpha thalassemia trait (hemoglobin S concentration 34%), 4% (1) with hemoglobin S trait and double gene deletion alpha thalassemia trait (hemoglobin S concentration 28%), 4% (1) with hemoglobin Lepore trait, and 4% (1) with hemoglobin G-Philadelphia trait with at least a single gene deletion alpha thalassemia trait (hemoglobin G-Philadelphia concentration 36%). Although the combination of MCV, hemoglobin, and red cell count available from the routine CBC were often helpful in discriminating iron deficiency from hemoglobinopathy, the frequent coexistence of both processes resulted in a need for further laboratory evaluation, both before and after iron repletion, to confirm the diagnosis. In a sample of American repeat apheresis donors, iron deficiency is present in the majority with recurrent low MCV values and hemoglobin levels ≥ 12.5 gm/dL. Concurrent hemoglobinopathy is also commonly present but may not be easily recognized in the setting of iron deficiency. The MCV is a useful screening tool to detect iron deficiency in a repeat blood donor population, however low MCV values should be further investigated in the blood donor setting to determine if iron replacement therapy is indicated.
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Comellato, Tommaso, Matteo Agostini i Stefan Schönert. "Topologies of $$^{76}$$Ge double-beta decay events and calibration procedure biases". European Physical Journal C 83, nr 3 (21.03.2023). http://dx.doi.org/10.1140/epjc/s10052-023-11396-z.
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AbstractThe analysis of the time profile of electrical signals produced by energy depositions in germanium detectors allows discrimination of events with different topologies. This is especially relevant for experiments searching for the neutrinoless double beta decay of $$^{76}$$ 76 Ge to distinguish the sought-after signal from other background sources. The standard calibration procedures used to tune the selection criteria for double-beta decay events use a $$^{228}$$ 228 Th source, because it provides samples of signal-like events. These samples exhibit energy spatial distributions with subtle different topologies compared to neutrinoless double-beta decay events. In this work, we will characterize these topological differences and, with the support of a $$^{56}$$ 56 Co source, evaluate biases and precision of calibration techniques which use such event samples. Our results will be particularly relevant for future experiments in which a solid estimation of the efficiency is required.
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Xia, Shangning, Suizhi Huang, Kexin Xu, Tao Li, Xun Chen, Ke Han i Shaobo Wang. "Optimization of convolutional neural networks for background suppression in the PandaX-III experiment". Journal of Physics G: Nuclear and Particle Physics, 28.09.2023. http://dx.doi.org/10.1088/1361-6471/acfe24.
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Abstract The tracks recorded by a gaseous detector provide a possibility for charged particle identi fication. For searching the neutrinoless double beta decay events of 136Xe in the PandaX-III experiment, we optimized the convolutional neural network based on the Monte Carlo simulation data to improve the signal-background discrimination power. EfficientNet is chosen as the baseline model and the optimization is performed by tuning the hyperparameters. In particular, the maximum discrimination power is achieved by optimizing the channel number of the top convolutional layer. In comparison with our previous work, the significance of discrimination has been improved by ∼70%.
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Comellato, Tommaso, Matteo Agostini i Stefan Schönert. "Charge-carrier collective motion in germanium detectors for $$\beta \beta $$-decay searches". European Physical Journal C 81, nr 1 (styczeń 2021). http://dx.doi.org/10.1140/epjc/s10052-021-08889-0.
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AbstractThe time analysis of the signal induced by the drift of charge carriers in high purity germanium detectors provides information on the event topology. Millions of charge carriers are produced in a typical event. Their initial distribution, stochastic diffusion and Coulomb self-repulsion affect the time structure of the signal. We present a comprehensive study of these effects and evaluate their impact on the event discrimination capabilities for the three geometries which will be used in the Legend experiment for neutrinoless double-beta decay.
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Yang, Litao. "Searching for $^{76}$Ge neutrinoless double beta decay with the CDEX-1B experiment". Chinese Physics C, 19.06.2024. http://dx.doi.org/10.1088/1674-1137/ad597b.
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Abstract We operated a p-type point contact high purity germanium (PPCGe) detector (CDEX-1B, 1.008 kg) in the China Jinping Underground Laboratory (CJPL) for 500.3 days to search for neutrinoless double beta ($\bb$) decay of $^{76}$Ge. A total of 504.3 kg$\cdot$day effective exposure data was accumulated. The anti-coincidence and the multi/single-site event (MSE/SSE) discrimination methods were used to suppress the background in the energy region of interest (ROI, 1989--2089 keV for this work) with a factor of 23. A background level of 0.33 counts/(keV$\cdot$kg$\cdot$yr) was achieved. The lower limit on the half life of $^{76}$Ge $\bb$ decay was constrained as $T_{1/2}^{0\nu}\ > \ {1.0}\times 10^{23}\ \rm yr\ (90\% \ C.L.)$, corresponding to the upper limits on the effective Majorana neutrino mass: $\langle m_{\beta\beta}\rangle < $ 3.2--7.5$\ \mathrm{eV}$.
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Agostini, M., G. Araujo, A. M. Bakalyarov, M. Balata, I. Barabanov, L. Baudis, C. Bauer i in. "Characterization of inverted coaxial $$^{76}$$Ge detectors in GERDA for future double-$$\beta $$ decay experiments". European Physical Journal C 81, nr 6 (czerwiec 2021). http://dx.doi.org/10.1140/epjc/s10052-021-09184-8.
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AbstractNeutrinoless double-$$\beta $$ β decay of $$^{76}$$ 76 Ge is searched for with germanium detectors where source and detector of the decay are identical. For the success of future experiments it is important to increase the mass of the detectors. We report here on the characterization and testing of five prototype detectors manufactured in inverted coaxial (IC) geometry from material enriched to 88% in $$^{76}$$ 76 Ge. IC detectors combine the large mass of the traditional semi-coaxial Ge detectors with the superior resolution and pulse shape discrimination power of point contact detectors which exhibited so far much lower mass. Their performance has been found to be satisfactory both when operated in vacuum cryostat and bare in liquid argon within the Gerda setup. The measured resolutions at the Q-value for double-$$\beta $$ β decay of $$^{76}$$ 76 Ge ($$Q_{\beta \beta }$$ Q β β = 2039 keV) are about 2.1 keV full width at half maximum in vacuum cryostat. After 18 months of operation within the ultra-low background environment of the GERmanium Detector Array (Gerda) experiment and an accumulated exposure of 8.5 kg$$\cdot $$ · year, the background index after analysis cuts is measured to be $$4.9^{+7.3}_{-3.4}\times 10^{-4} \ \text {counts}/(\text {keV} \cdot \text {kg} \cdot \text {year})$$ 4 . 9 - 3.4 + 7.3 × 10 - 4 counts / ( keV · kg · year ) around $$Q_{\beta \beta }$$ Q β β . This work confirms the feasibility of IC detectors for the next-generation experiment Legend.
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Pompa, Federica, Thomas Schwetz i Jing-Yu Zhu. "Impact of nuclear matrix element calculations for current and future neutrinoless double beta decay searches". Journal of High Energy Physics 2023, nr 6 (19.06.2023). http://dx.doi.org/10.1007/jhep06(2023)104.
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Abstract Nuclear matrix elements (NME) are a crucial input for the interpretation of neutrinoless double beta decay data. We consider a representative set of recent NME calculations from different methods and investigate the impact on the present bound on the effective Majorana mass mββ by performing a combined analysis of the available data as well as on the sensitivity reach of future projects. A crucial role is played by the recently discovered short-range contribution to the NME, induced by light Majorana neutrino masses. Depending on the NME model and the relative sign of the long- and short-range contributions, the current 3σ bound can change between mββ< 40 meV and 600 meV. The sign-uncertainty may either boost the sensitivity of next-generation experiments beyond the region for mββ predicted for inverted mass ordering or prevent even advanced setups to reach this region. Furthermore, we study the possibility to distinguish between different NME calculations by assuming a positive signal and by combining measurements from different isotopes. Such a discrimination will be impossible if the relative sign of the long- and short-range contribution remains unknown, but can become feasible if mββ ≳ 40 meV and if the relative sign is known to be positive. Sensitivities will be dominated by the advanced 76Ge and 136Xe setups assumed here, but NME model-discrimination improves if data from a third isotope is added, e.g., from 130Te or 100Mo.
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Dai, W. H., H. Ma, Z. Zeng, L. T. Yang, Q. Yue i J. P. Cheng. "Virtual segmentation of a small contact HPGe detector: inference of hit positions of single-site events via pulse shape analysis". European Physical Journal C 84, nr 3 (21.03.2024). http://dx.doi.org/10.1140/epjc/s10052-024-12645-5.
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AbstractExploring hit positions of recorded events can help to understand and suppress backgrounds in rare event searches. We propose a pulse shape analysis method to discriminate single-site events (SSEs) in the inner and outer layer of a small contact P-type germanium detector (HPGe). SSEs in the inner and outer layer have different pulse shape features, of which the rise time of the $$(T_{Q})$$ ( T Q ) and current pulse $$(T_{I})$$ ( T I ) are selected for discrimination. A 500 Bq Thorium-228 (Th-228) source is used to determine the boundaries between the two layers. The double escape peak events from 2614.5 keV $$\gamma $$ γ -ray are selected as typical SSEs, their numbers in the two layers are used to calculate the volumes and shapes of those layers. Considering the statistical and systematic uncertainties, the inner layer volume is evaluated to be 47.2% ± 0.26%(stat.) ± 0.18%(sys.) ± 0.22%(sys.) of the total sensitive volume. Selecting the inner layer as the analysis volume can reduce the external background in the signal region of Ge-76 neutrinoless double beta (0$$\nu \beta \beta )$$ ν β β ) decay. We use the Th-228 data to validate the inner layer model and evaluate the background suppression power in the 0$$\nu \beta \beta $$ ν β β signal region $$(Q_{\beta \beta }=2039$$ ( Q β β = 2039 keV). The virtual segmentation further reduces the background from the external Th-228 source by about 10%. The virtual segmentation could be used to efficiently suppress surface background like electrons from Ar-42 decay in 0$$\nu \beta \beta $$ ν β β experiments using germanium detectors immersed in liquid argon.
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Agostini, M., G. Araujo, A. M. Bakalyarov, M. Balata, I. Barabanov, L. Baudis, C. Bauer i in. "Pulse shape analysis in Gerda Phase II". European Physical Journal C 82, nr 4 (kwiecień 2022). http://dx.doi.org/10.1140/epjc/s10052-022-10163-w.
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AbstractThe GERmanium Detector Array (Gerda) collaboration searched for neutrinoless double-$$\beta $$ β decay in $$^{76}$$ 76 Ge using isotopically enriched high purity germanium detectors at the Laboratori Nazionali del Gran Sasso of INFN. After Phase I (2011–2013), the experiment benefited from several upgrades, including an additional active veto based on LAr instrumentation and a significant increase of mass by point-contact germanium detectors that improved the half-life sensitivity of Phase II (2015–2019) by an order of magnitude. At the core of the background mitigation strategy, the analysis of the time profile of individual pulses provides a powerful topological discrimination of signal-like and background-like events. Data from regular $$^{228}$$ 228 Th calibrations and physics data were both considered in the evaluation of the pulse shape discrimination performance. In this work, we describe the various methods applied to the data collected in Gerda Phase II corresponding to an exposure of 103.7 kg year. These methods suppress the background by a factor of about 5 in the region of interest around $$Q_{\beta \beta }= 2039$$ Q β β = 2039 keV, while preserving $$(81\pm 3)$$ ( 81 ± 3 ) % of the signal. In addition, an exhaustive list of parameters is provided which were used in the final data analysis.
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Ahmine, A., A. Armatol, I. Bandac, L. Bergé, J. M. Calvo-Mozota, P. Carniti, M. Chapellier i in. "Enhanced light signal for the suppression of pile-up events in Mo-based bolometers for the 0$$\nu \beta \beta $$ decay search." European Physical Journal C 83, nr 5 (6.05.2023). http://dx.doi.org/10.1140/epjc/s10052-023-11519-6.
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AbstractRandom coincidences of events could be one of the main sources of background in the search for neutrino-less double-beta decay of $$^{100}$$ 100 Mo with macro-bolometers, due to their modest time resolution. Scintillating bolometers as those based on Li$$_2$$ 2 MoO$$_4$$ 4 crystals and employed in the CROSS and CUPID experiments can eventually exploit the coincident fast signal detected in a light detector to reduce this background. However, the scintillation provides a modest signal-to-noise ratio, making difficult a pile-up pulse-shape recognition and rejection at timescales shorter than a few ms. Neganov–Trofimov–Luke assisted light detectors (NTL-LDs) offer the possibility to effectively increase the signal-to-noise ratio, preserving a fast time-response, and enhance the capability of pile-up rejection via pulse shape analysis. In this article we present: (a) an experimental work performed with a Li$$_2$$ 2 MoO$$_4$$ 4 scintillating bolometer, studied in the framework of the CROSS experiment, and utilizing a NTL-LD; (b) a simulation method to reproduce, synthetically, randomly coincident two-neutrino double-beta decay events; (c) a new analysis method based on a pulse-shape discrimination algorithm capable of providing high pile-up rejection efficiencies. We finally show how the NTL-LDs offer a balanced solution between performance and complexity to reach background index $$\sim $$ ∼ $$10^{-4}$$ 10 - 4 counts/keV/kg/year with 280 g Li$$_2$$ 2 MoO$$_4$$ 4 ($$^{100}$$ 100 Mo enriched) bolometers at 3034 keV, the Q$$_{\beta \beta }$$ β β of the double-beta decay, and target the goal of a next generation experiment like CUPID.
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Simón, A., Y. Ifergan, A. B. Redwine, R. Weiss-Babai, L. Arazi, C. Adams, H. Almazán i in. "Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution". Journal of High Energy Physics 2021, nr 7 (lipiec 2021). http://dx.doi.org/10.1007/jhep07(2021)146.
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Abstract Next-generation neutrinoless double beta decay experiments aim for half-life sensitivities of ∼ 1027 yr, requiring suppressing backgrounds to < 1 count/tonne/yr. For this, any extra background rejection handle, beyond excellent energy resolution and the use of extremely radiopure materials, is of utmost importance. The NEXT experiment exploits differences in the spatial ionization patterns of double beta decay and single-electron events to discriminate signal from background. While the former display two Bragg peak dense ionization regions at the opposite ends of the track, the latter typically have only one such feature. Thus, comparing the energies at the track extremes provides an additional rejection tool. The unique combination of the topology-based background discrimination and excellent energy resolution (1% FWHM at the Q-value of the decay) is the distinguishing feature of NEXT. Previous studies demonstrated a topological background rejection factor of ∼ 5 when reconstructing electron-positron pairs in the 208Tl 1.6 MeV double escape peak (with Compton events as background), recorded in the NEXT-White demonstrator at the Laboratorio Subterráneo de Canfranc, with 72% signal efficiency. This was recently improved through the use of a deep convolutional neural network to yield a background rejection factor of ∼ 10 with 65% signal efficiency. Here, we present a new reconstruction method, based on the Richardson-Lucy deconvolution algorithm, which allows reversing the blurring induced by electron diffusion and electroluminescence light production in the NEXT TPC. The new method yields highly refined 3D images of reconstructed events, and, as a result, significantly improves the topological background discrimination. When applied to real-data 1.6 MeV e−e+ pairs, it leads to a background rejection factor of 27 at 57% signal efficiency.
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Li, Tao, Shaobo Wang, Yu Chen, Ke Han, Heng Lin, Kaixiang Ni, Wei Wang, Yiliu Xu i An’ni Zou. "Signal identification with Kalman Filter towards background-free neutrinoless double beta decay searches in gaseous detectors". Journal of High Energy Physics 2021, nr 6 (czerwiec 2021). http://dx.doi.org/10.1007/jhep06(2021)106.
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Abstract Particle tracks and differential energy loss measured in high pressure gaseous detectors can be exploited for event identification in neutrinoless double beta decay (0νββ) searches. We develop a new method based on Kalman Filter in a Bayesian formalism (KFB) to reconstruct meandering tracks of MeV-scale electrons. With simulation data, we compare the signal and background discrimination power of the KFB method assuming different detector granularities and energy resolutions. Typical background from 232Th and 238U decay chains can be suppressed by another order of magnitude than that in published literatures, approaching the background-free regime. For the proposed PandaX-III experiment, the 0νββ search half-life sensitivity at the 90% confidence level would reach 2.7× 1026 yr with 5-year live time, a factor of 2.7 improvement over the initial design target.
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Jany, A., M. Misiaszek, T. Mroz, K. Panas, G. Zuzel, M. Wojcik, K. Brudecki i in. "Fabrication, characterization and analysis of a prototype high purity germanium detector for $$^{76}$$Ge-based neutrinoless double beta decay experiments". European Physical Journal C 81, nr 1 (styczeń 2021). http://dx.doi.org/10.1140/epjc/s10052-020-08781-3.
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AbstractExperiments searching for the neutrinoless double beta decay in $$^{76}$$ 76 Ge are currently achieving the lowest background level and, in connection with the excellent energy resolution of germanium detectors, they exhibit the best discovery potential for the decay. Expansion to a ton scale of the active target mass is presently considered – in this case on-site production of the detectors may be an option. In this paper we describe the fabrication and characterization procedures of a prototype detector with a small p+ contact, which enhances the abilities of the pulse shape discrimination – one of the most important tools for background reduction. Simulations of the shapes of pulses from the detector were carried out and tuned, taking the advantage of the fact that all the parameters of the Ge crystal, cryostat and of the spectroscopic chain were known. As a result, the pulse shape analyses performed on the simulated and measured data agree very well. The worked out method allows to optimize geometry and crystal parameters in terms of pulse shape analysis efficiency, before the actual production of the detectors.
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Agostini, M., A. M. Bakalyarov, E. Andreotti, M. Balata, I. Barabanov, L. Baudis, N. Barros i in. "Characterization of 30 $$^{76}$$Ge enriched Broad Energy Ge detectors for GERDA Phase II". European Physical Journal C 79, nr 11 (listopad 2019). http://dx.doi.org/10.1140/epjc/s10052-019-7353-8.
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AbstractThe 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 $$^{76}$$76Ge into $$^{76}$$76Se+2e$$^-$$-. Gerda has been conceived in two phases. Phase II, which started in December 2015, features several novelties including 30 new 76Ge enriched 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 accuracy of pulse shape simulation codes.
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Anchisi, Stéphanie, Jessica Guerra i Dominique Garcin. "RIG-I ATPase Activity and Discrimination of Self-RNA versus Non-Self-RNA". mBio 6, nr 2 (3.03.2015). http://dx.doi.org/10.1128/mbio.02349-14.
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ABSTRACTMany RNA viruses are detected by retinoic acid-inducible gene i (RIG-I), a cytoplasmic sensor that triggers an antiviral response upon binding non-self-RNA that contains a stretch of double-stranded RNA (dsRNA) bearing a base-paired 5′ ppp nucleotide. To gain insight into how RIG-I discriminates between self-RNA and non-self-RNA, we used duplexes whose complementary bottom strand contained both ribo- and deoxynucleotides. These duplexes were examined for their binding to RIG-I and their relative abilities to stimulate ATPase activity, to induce RIG-I dimerization on the duplex, and to induce beta interferon (IFN-β) expression. We show that the chemical nature of the bottom strand is not critical for RIG-I binding. However, two key ribonucleotides, at positions 2 and 5 on the bottom strand, are minimally required for the RIG-I ATPase activity, which is necessary but not sufficient for IFN-β stimulation. We find that duplexes with shorter stretches of dsRNA, as model self-RNAs, bind less stably to RIG-I but nevertheless have an enhanced ability to stimulate the ATPase. Moreover, ATPase activity promotes RIG-I recycling on RIG-I/dsRNA complexes. Since pseudo-self-RNAs bind to RIG-I less stably, they are preferentially recycled by ATP hydrolysis that weakens the helicase domain binding of dsRNA. Our results suggest that one function of the ATPase is to restrict RIG-I signaling to its interaction with non-self-RNA. A model of how this discrimination occurs as a function of dsRNA length is presented.IMPORTANCEThe innate immune response to pathogens is based on the discrimination between self-RNA and non-self-RNA. The main determinants of this detection for RNA viruses are specific pathogen-associated molecular patterns (PAMPs) of RNA, which are detected by dedicated cytoplasmic pattern recognition receptors (PRRs). RIG-I is a PRR that specifically detects short viral dsRNAs amid a sea of cellular RNAs. Here we study the determinants of this discrimination and how RIG-I ATPase activity, the only enzymatic activity of this sensor, contributes to its activation in a manner restricted to its interaction with non-self-RNAs. We also show how the innate immune response evolves during infection via IFN expression, from a state in which discrimination of self-RNA from non-self-RNA is most important to one in which this discrimination is sacrificed for the effectiveness of the antiviral response.
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Callaghan, E. J., B. L. Goldblum, J. A. Brown, T. A. Laplace, J. J. Manfredi, M. Yeh i G. D. Orebi Gann. "Measurement of proton light yield of water-based liquid scintillator". European Physical Journal C 83, nr 2 (10.02.2023). http://dx.doi.org/10.1140/epjc/s10052-023-11242-2.
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AbstractThe proton light yield of liquid scintillators is an important property in the context of their use in large-scale neutrino experiments, with direct implications for neutrino-proton scattering measurements and the discrimination of fast neutrons from inverse $$\beta $$ β -decay coincidence signals. This work presents the first measurement of the proton light yield of a water-based liquid scintillator (WbLS) formulated from 5% linear alkyl benzene (LAB), at energies below 20 MeV, as well as a measurement of the proton light yield of a pure LAB + 2 g/L 2,5-diphenyloxazole (PPO) mixture (LABPPO). The measurements were performed using a double time-of-flight method and a pulsed neutron beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The proton light yields were measured relative to that of a 477 keV electron. The relative proton light yield of WbLS was approximately 3.8% lower than that of LABPPO, itself exhibiting a relative proton light yield 15–20% higher than previous measurements of an analogous anoxic sample. The observed quenching is not compatible with the Birks model for either material, but is well described with the addition of Chou’s bimolecular quenching term.
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"Explaining the Causes and Contexts of the Formation of Organizational Insentience in the Red Crescent Society of Tehran". Journal of Rescue and Relief, 8.01.2023, 9–20. http://dx.doi.org/10.32592/jorar.2023.15.1.2.
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INTRODUCTION The phenomenon of organizational insentience has been one of the main challenges in recent years and refers to a situation in which the employees of an organization have become indifferent to their organizational environment. The current research was conducted to investigate the causes and contexts of the formation of organizational insentience in the Red Crescent Society of Tehran province, Iran. METHODS: This applied study was conducted based on the descriptive-correlation method of data collection. The statistical population of this research included all the managers of Red Crescent Organization in Tehran province in 2021. The samples (n=90) were selected using Cochran's statistical formula and stratified random sampling. The required data were collected using a researcher made organizational insentience questionnaire. The validity and reliability of the questionnaire were checked and confirmed. The collected data were analyzed in Smart PLS software using structural equation modeling with partial least squares approach. FINDINGS: The results of the research showed that causal conditions had a direct, positive, and significant effect on the central category with a standard beta coefficient of 0.725, t=17.625, and P=0.001 at the level of one percent error. Moreover, contextual conditions with a beta coefficient of 0.410, t=3.107, and P=0.002 had a direct, positive, and significant effect on the category of strategies at the level of one percent error. Intervening conditions had a direct, positive, and significant effect on strategies at the level of one percent error (standard beta coefficient=0.221, t=3.008, and P=0.003). The central category had a direct, positive, and significant effect on the strategy category with a beta coefficient of 0.334, t=2.282, and P=0.023 at the five percent error level. Based on the results, at one percent error level, the strategies presented in the research had a direct, positive, and significant effect on the outcomes (standard beta coefficient=0.347, t=3.769, and P=0.000). In total, the results showed the existence of organizational insentience in the Red Crescent Organization of Tehran province, which can be reduced by applying appropriate methods. CONCLUSION: According to the findings, by reducing the sense of meaninglessness, double standards, eliminating organizational discrimination, applying appropriate procedures in strategies and their implementation, paying attention to the structural dimensions of the Red Crescent Society in Tehran province, and implementing meritocracy management, it would be possible to increase organizational social capital, the level of interest, commitment, and responsibility of employees towards the Society and work, organizational independence, organizational justice, the atmosphere of trust, and supportive behaviors from the Society and employees. By adopting these measures, a step would be taken toward preventing the formation of organizational insentience in the Red Crescent Society of Tehran province.
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Huang, Guo-yuan, i Shun Zhou. "Tentative sensitivity of future 0νββ-decay experiments to neutrino masses and Majorana CP phases". Journal of High Energy Physics 2021, nr 3 (marzec 2021). http://dx.doi.org/10.1007/jhep03(2021)084.
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Abstract In the near future, the neutrinoless double-beta (0νββ) decay experiments will hopefully reach the sensitivity of a few meV to the effective neutrino mass |mββ|. In this paper, we tentatively examine the sensitivity of future 0νββ-decay experiments to neutrino masses and Majorana CP phases by following the Bayesian statistical approach. Provided experimental setups corresponding to the experimental sensitivity of |mββ| ≃ 1 meV, the null observation of 0νββ decays in the case of normal neutrino mass ordering leads to a very competitive bound on the lightest neutrino mass m1. Namely, the 95% credible interval in the Bayesian approach turns out to be 1.6 meV ≲ m1 ≲ 7.3 meV or 0.3 meV ≲ m1 ≲ 5.6 meV when the uniform prior on m1/eV or on log10(m1/eV) is adopted. Moreover, one of two Majorana CP phases is strictly constrained, i.e., 140° ≲ ρ ≲ 220° for both scenarios of prior distributions of m1. In contrast, if a relatively worse experimental sensitivity of |mββ| ≃ 10 meV is assumed, the constraint on the lightest neutrino mass becomes accordingly 0.6 meV ≲ m1 ≲ 26 meV or 0 ≲ m1 ≲ 6.1 meV, while two Majorana CP phases will be essentially unconstrained. In the same statistical framework, the prospects for the determination of neutrino mass ordering and the discrimination between Majorana and Dirac nature of massive neutrinos in the 0νββ-decay experiments are also discussed. Given the experimental sensitivity of |mββ| ≃ 10 meV (or 1 meV), the strength of evidence to exclude the Majorana nature under the null observation of 0νββ decays is found to be inconclusive (or strong), no matter which of two priors on m1 is taken.
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Liebe, Sebastian, Edgar Maiss i Mark Varrelmann. "The arms race between beet necrotic yellow vein virus and host resistance in sugar beet". Frontiers in Plant Science 14 (31.03.2023). http://dx.doi.org/10.3389/fpls.2023.1098786.
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Beet necrotic yellow vein virus (BNYVV) causes rhizomania disease in sugar beet (Beta vulgaris), which is controlled since more than two decades by cultivars harboring the Rz1 resistance gene. The development of resistance-breaking strains has been favored by a high selection pressure on the soil-borne virus population. Resistance-breaking is associated with mutations at amino acid positions 67-70 (tetrad) in the RNA3 encoded pathogenicity factor P25 and the presence of an additional RNA component (RNA5). However, natural BNYVV populations are highly diverse making investigations on the resistance-breaking mechanism rather difficult. Therefore, we applied a reverse genetic system for BNYVV (A type) to study Rz1 resistance-breaking by direct agroinoculation of sugar beet seedlings. The bioassay allowed a clear discrimination between susceptible and Rz1 resistant plants already four weeks after infection, and resistance-breaking was independent of the sugar beet Rz1 genotype. A comprehensive screen of natural tetrads for resistance-breaking revealed several new mutations allowing BNYVV to overcome Rz1. The supplementation of an additional RNA5 encoding the pathogenicity factor P26 allowed virus accumulation in the Rz1 genotype independent of the P25 tetrad. This suggests the presence of two distinct resistance-breaking mechanisms allowing BNYVV to overcome Rz1. Finally, we showed that the resistance-breaking effect of the tetrad and the RNA5 is specific to Rz1 and has no effect on the stability of the second resistance gene Rz2. Consequently, double resistant cultivars (Rz1+Rz2) should provide effective control of Rz1 resistance-breaking strains. Our study highlights the flexibility of the viral genome allowing BNYVV to overcome host resistance, which underlines the need for a continuous search for alternative resistance genes.
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Arnquist, I. J., F. T. Avignone, A. S. Barabash, C. J. Barton, F. E. Bertrand, E. Blalock, B. Bos i in. "$$\alpha $$-event characterization and rejection in point-contact HPGe detectors". European Physical Journal C 82, nr 3 (marzec 2022). http://dx.doi.org/10.1140/epjc/s10052-022-10161-y.
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AbstractP-type point contact (PPC) HPGe detectors are a leading technology for rare event searches due to their excellent energy resolution, low thresholds, and multi-site event rejection capabilities. We have characterized a PPC detector’s response to $$\alpha $$ α particles incident on the sensitive passivated and p$$^+$$ + surfaces, a previously poorly-understood source of background. The detector studied is identical to those in the MajoranaDemonstrator experiment, a search for neutrinoless double-beta decay ($$0\nu \beta \beta $$ 0 ν β β ) in $$^{76}$$ 76 Ge. $$\alpha $$ α decays on most of the passivated surface exhibit significant energy loss due to charge trapping, with waveforms exhibiting a delayed charge recovery (DCR) signature caused by the slow collection of a fraction of the trapped charge. The DCR is found to be complementary to existing methods of $$\alpha $$ α identification, reliably identifying $$\alpha $$ α background events on the passivated surface of the detector. We demonstrate effective rejection of all surface $$\alpha $$ α events (to within statistical uncertainty) with a loss of only 0.2% of bulk events by combining the DCR discriminator with previously-used methods. The DCR discriminator has been used to reduce the background rate in the $$0\nu \beta \beta $$ 0 ν β β region of interest window by an order of magnitude in the MajoranaDemonstrator and will be used in the upcoming LEGEND-200 experiment.
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Mathew, Jerin, Divya Bharatkumar Adhia, Mark Llewellyn Smith, Dirk De Ridder i Ramakrishnan Mani. "Closed-Loop Infraslow Brain–Computer Interface can Modulate Cortical Activity and Connectivity in Individuals With Chronic Painful Knee Osteoarthritis: A Secondary Analysis of a Randomized Placebo-Controlled Clinical Trial". Clinical EEG and Neuroscience, 26.07.2024. http://dx.doi.org/10.1177/15500594241264892.
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Introduction. Chronic pain is a percept due to an imbalance in the activity between sensory-discriminative, motivational-affective, and descending pain-inhibitory brain regions. Evidence suggests that electroencephalography (EEG) infraslow fluctuation neurofeedback (ISF-NF) training can improve clinical outcomes. It is unknown whether such training can induce EEG activity and functional connectivity (FC) changes. A secondary data analysis of a feasibility clinical trial was conducted to determine whether EEG ISF-NF training can significantly alter EEG activity and FC between the targeted cortical regions in people with chronic painful knee osteoarthritis (OA). Methods. A parallel, two-arm, double-blind, randomized, sham-controlled clinical trial was conducted. People with chronic knee pain associated with OA were randomized to receive sham NF training or source-localized ratio ISF-NF training protocol to down-train ISF bands at the somatosensory (SSC), dorsal anterior cingulate (dACC), and uptrain pregenual anterior cingulate cortices (pgACC). Resting state EEG was recorded at baseline and immediate post-training. Results. The source localization mapping demonstrated a reduction ( P = .04) in the ISF band activity at the left dorsolateral prefrontal cortex (LdlPFC) in the active NF group. Region of interest analysis yielded significant differences for ISF ( P = .008), slow ( P = .007), beta ( P = .043), and gamma ( P = .012) band activities at LdlPFC, dACC, and bilateral SSC. The FC between pgACC and left SSC in the delta band was negatively correlated with pain bothersomeness in the ISF-NF group. Conclusion. The EEG ISF-NF training can modulate EEG activity and connectivity in individuals with chronic painful knee osteoarthritis, and the observed EEG changes correlate with clinical pain measures.