Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 111
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
J Dairy Sci ; 106(1): 407-420, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36400619

RESUMO

Sperm motility is directly related to the ability of sperm to move through the female reproductive tract to reach the ovum. Sperm motility is a complex trait that is influenced by environmental and genetic factors and is associated with male fertility, oocyte penetration rate, and reproductive success of cattle. In this study we carried out a GWAS in Italian Holstein bulls to identify candidate regions and genes associated with variations in progressive and total motility (PM and TM, respectively). After quality control, the final data set consisted of 5,960 records from 949 bulls having semen collected in 10 artificial insemination stations and genotyped at 412,737 SNPs (call rate >95%; minor allele frequency >5%). (Co)variance components were estimated using single trait mixed models, and associations between SNPs and phenotypes were assessed using a genomic BLUP approach. Ten windows that explained the greatest percentage of genetic variance were located on Bos taurus autosomes 1, 2, 4, 6, 7, 23, and 26 for TM and Bos taurus autosomes 1, 2, 4, 6, 8, 16, 23, and 26 for PM. A total of 150 genes for TM and 72 genes for PM were identified within these genomic regions. Gene Ontology enrichment analyses identified significant Gene Ontology terms involved with energy homeostasis, membrane functions, sperm-egg interactions, protection against oxidative stress, olfactory receptors, and immune system. There was significant enrichment of quantitative trait loci for fertility, calving ease, immune response, feed intake, and carcass weight within the candidate windows. These results contribute to understanding the architecture of the genetic control of sperm motility and may aid in the development of strategies to identify subfertile bulls and improve reproductive success.


Assuntos
Sêmen , Motilidade dos Espermatozoides , Animais , Bovinos/genética , Feminino , Masculino , Genômica , Locos de Características Quantitativas , Sêmen/fisiologia , Motilidade dos Espermatozoides/genética , Espermatozoides
2.
Phys Rev Lett ; 129(22): 222501, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36493444

RESUMO

The Cryogenic Underground Observatory for Rare Events (CUORE) at Laboratori Nazionali del Gran Sasso of INFN in Italy is an experiment searching for neutrinoless double beta (0νßß) decay. Its main goal is to investigate this decay in ^{130}Te, but its ton-scale mass and low background make CUORE sensitive to other rare processes as well. In this Letter, we present our first results on the search for 0νßß decay of ^{128}Te, the Te isotope with the second highest natural isotopic abundance. We find no evidence for this decay, and using a Bayesian analysis we set a lower limit on the ^{128}Te 0νßß decay half-life of T_{1/2}>3.6×10^{24} yr (90% CI). This represents the most stringent limit on the half-life of this isotope, improving by over a factor of 30 the previous direct search results, and exceeding those from geochemical experiments for the first time.


Assuntos
Granisetron , Meia-Vida , Teorema de Bayes
3.
Phys Rev Lett ; 129(16): 161805, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36306777

RESUMO

We report on a blinded analysis of low-energy electronic recoil data from the first science run of the XENONnT dark matter experiment. Novel subsystems and the increased 5.9 ton liquid xenon target reduced the background in the (1, 30) keV search region to (15.8±1.3) events/(ton×year×keV), the lowest ever achieved in a dark matter detector and ∼5 times lower than in XENON1T. With an exposure of 1.16 ton-years, we observe no excess above background and set stringent new limits on solar axions, an enhanced neutrino magnetic moment, and bosonic dark matter.

4.
Phys Rev Lett ; 126(9): 091301, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33750173

RESUMO

We report on a search for nuclear recoil signals from solar ^{8}B neutrinos elastically scattering off xenon nuclei in XENON1T data, lowering the energy threshold from 2.6 to 1.6 keV. We develop a variety of novel techniques to limit the resulting increase in backgrounds near the threshold. No significant ^{8}B neutrinolike excess is found in an exposure of 0.6 t×y. For the first time, we use the nondetection of solar neutrinos to constrain the light yield from 1-2 keV nuclear recoils in liquid xenon, as well as nonstandard neutrino-quark interactions. Finally, we improve upon world-leading constraints on dark matter-nucleus interactions for dark matter masses between 3 and 11 GeV c^{-2} by as much as an order of magnitude.

5.
Phys Rev Lett ; 122(7): 071301, 2019 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-30848617

RESUMO

We present first results on the scalar coupling of weakly interacting massive particles (WIMPs) to pions from 1 t yr of exposure with the XENON1T experiment. This interaction is generated when the WIMP couples to a virtual pion exchanged between the nucleons in a nucleus. In contrast to most nonrelativistic operators, these pion-exchange currents can be coherently enhanced by the total number of nucleons and therefore may dominate in scenarios where spin-independent WIMP-nucleon interactions are suppressed. Moreover, for natural values of the couplings, they dominate over the spin-dependent channel due to their coherence in the nucleus. Using the signal model of this new WIMP-pion channel, no significant excess is found, leading to an upper limit cross section of 6.4×10^{-46} cm^{2} (90% confidence level) at 30 GeV/c^{2} WIMP mass.

6.
Phys Rev Lett ; 122(14): 141301, 2019 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31050482

RESUMO

We report the first experimental results on spin-dependent elastic weakly interacting massive particle (WIMP) nucleon scattering from the XENON1T dark matter search experiment. The analysis uses the full ton year exposure of XENON1T to constrain the spin-dependent proton-only and neutron-only cases. No significant signal excess is observed, and a profile likelihood ratio analysis is used to set exclusion limits on the WIMP-nucleon interactions. This includes the most stringent constraint to date on the WIMP-neutron cross section, with a minimum of 6.3×10^{-42} cm^{2} at 30 GeV/c^{2} and 90% confidence level. The results are compared with those from collider searches and used to exclude new parameter space in an isoscalar theory with an axial-vector mediator.

7.
Phys Rev Lett ; 123(25): 251801, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31922764

RESUMO

We report constraints on light dark matter (DM) models using ionization signals in the XENON1T experiment. We mitigate backgrounds with strong event selections, rather than requiring a scintillation signal, leaving an effective exposure of (22±3) tonne day. Above ∼0.4 keV_{ee}, we observe <1 event/(tonne day keV_{ee}), which is more than 1000 times lower than in similar searches with other detectors. Despite observing a higher rate at lower energies, no DM or CEvNS detection may be claimed because we cannot model all of our backgrounds. We thus exclude new regions in the parameter spaces for DM-nucleus scattering for DM masses m_{χ} within 3-6 GeV/c^{2}, DM-electron scattering for m_{χ}>30 MeV/c^{2}, and absorption of dark photons and axionlike particles for m_{χ} within 0.186-1 keV/c^{2}.

8.
Phys Rev Lett ; 123(24): 241803, 2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31922867

RESUMO

Direct dark matter detection experiments based on a liquid xenon target are leading the search for dark matter particles with masses above ∼5 GeV/c^{2}, but have limited sensitivity to lighter masses because of the small momentum transfer in dark matter-nucleus elastic scattering. However, there is an irreducible contribution from inelastic processes accompanying the elastic scattering, which leads to the excitation and ionization of the recoiling atom (the Migdal effect) or the emission of a bremsstrahlung photon. In this Letter, we report on a probe of low-mass dark matter with masses down to about 85 MeV/c^{2} by looking for electronic recoils induced by the Migdal effect and bremsstrahlung using data from the XENON1T experiment. Besides the approach of detecting both scintillation and ionization signals, we exploit an approach that uses ionization signals only, which allows for a lower detection threshold. This analysis significantly enhances the sensitivity of XENON1T to light dark matter previously beyond its reach.

9.
Phys Rev Lett ; 121(11): 111302, 2018 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-30265108

RESUMO

We report on a search for weakly interacting massive particles (WIMPs) using 278.8 days of data collected with the XENON1T experiment at LNGS. XENON1T utilizes a liquid xenon time projection chamber with a fiducial mass of (1.30±0.01) ton, resulting in a 1.0 ton yr exposure. The energy region of interest, [1.4,10.6] keV_{ee} ([4.9,40.9] keV_{nr}), exhibits an ultralow electron recoil background rate of [82_{-3}^{+5}(syst)±3(stat)] events/(ton yr keV_{ee}). No significant excess over background is found, and a profile likelihood analysis parametrized in spatial and energy dimensions excludes new parameter space for the WIMP-nucleon spin-independent elastic scatter cross section for WIMP masses above 6 GeV/c^{2}, with a minimum of 4.1×10^{-47} cm^{2} at 30 GeV/c^{2} and a 90% confidence level.

10.
Artigo em Inglês | MEDLINE | ID: mdl-29521567

RESUMO

The principal aim of this study was to monitor the occurrence of some metals and polycyclic aromatic hydrocarbons (PAHs) in fish and mussels from the Gulf of Naples. A comparison with previous researches of the same area was carried out, and the intakes of these compounds through the diet and their effect on the tolerable intake values (when available) were assessed. Cadmium (Cd), chromium (Cr), and lead (Pb) were detected by flameless atomic absorption spectroscopy (Cd, Cr, and Pb); arsenic (As) and mercury (Hg) were detected by applying the hydride method. PAHs were detected by high-performance liquid chromatography. Widespread contamination was found. Among the metals, Hg showed the highest maximum levels of 284.94 ng/g wet weight (ww) in fish and 480.00 ng/g ww in mussels. Chrysene, phenanthrene, fluoranthene, anthracene, and benzo[k]fluoranthene were the most common PAHs in fish, whereas benzo[a]anthracene, pyrene, phenanthrene, acenaphthylene, and acenaphthene were the most frequently occurring compounds in mussels. The concentrations of As, Cr, Hg, Pb, and PAHs in fish were found to decrease over a period of 30 years, whereas the Cd levels remained constant. The Hg, Pb, and PAH levels in mussels increased over the period 2010 to 2016. Finally, the average consumption of mussels led to the highest effect on the Tolerable Daily Intake of Hg, which was exceeded by 19%.


Assuntos
Arsênio/análise , Monitoramento Ambiental , Atividades Humanas , Metais/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Alimentos Marinhos/análise , Animais , Bivalves/química , Cádmio/análise , Cromo/análise , Monitoramento Ambiental/métodos , Produtos Pesqueiros/análise , Peixes , Humanos , Itália , Chumbo/análise , Mercúrio/análise , Poluentes Químicos da Água/análise
11.
Eur J Appl Physiol ; 116(7): 1395-410, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27225620

RESUMO

PURPOSE: We analyzed the best performance times of master cycling athletes in the 200-3000 m track competitions to estimate the decay of maximal aerobic power (MAP) and anaerobic capacity (AnS) with aging. METHODS: In various decades of age (30-80 years), MAP and AnS were estimated using an iterative procedure as the values that minimize the difference between: (1) the metabolic power ([Formula: see text]) necessary to cover a given distance (d) in the time t and; (2) the maximal metabolic power ([Formula: see text]) maintained at a constant level throughout the competition. RESULTS: MAP started decreasing at 45 years of age. Thereafter, it showed an average percent rate of decrease of about 16 % for decade, as previously shown in other classes of master athletes. In addition, AnS seemed to decay by about 11 % every 10 years from the second part of the fifth decade. CONCLUSIONS: The decay of MAP occurred in spite of the active lifestyle of the subjects and it may be attributed to the progressive impairment of maximal O2 delivery and/or of peripheral O2 utilization. The loss of AnS might derive from the progressive loss of muscle mass occurring after the fifth decade of life, to the progressive qualitative deterioration of the anaerobic energy yielding pathways or to the lower capacity of MN recruitment during maximal efforts. The proposed approach may be applied to other types of human locomotion of whom the relationship between performance t and [Formula: see text] is known.


Assuntos
Envelhecimento/fisiologia , Limiar Anaeróbio/fisiologia , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Tolerância ao Exercício/fisiologia , Modelos Biológicos , Adulto , Idoso , Idoso de 80 Anos ou mais , Anaerobiose/fisiologia , Simulação por Computador , Exercício Físico/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia
12.
Comput Methods Appl Mech Eng ; 293: 462-480, 2015 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-26664007

RESUMO

In this paper, we perform a comparative analysis between two computational methods for virtual stent deployment: a novel fast virtual stenting method, which is based on a spring-mass model, is compared with detailed finite element analysis in a sequence of in silico experiments. Given the results of the initial comparison, we present a way to optimise the fast method by calibrating a set of parameters with the help of a genetic algorithm, which utilises the outcomes of the finite element analysis as a learning reference. As a result of the calibration phase, we were able to substantially reduce the force measure discrepancy between the two methods and validate the fast stenting method by assessing the differences in the final device configurations.

13.
Ann Ig ; 26(4): 330-43, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25001123

RESUMO

INTRODUCTION: The Rapid Alert System was established by the European Union (EC Regulation 178/2002 Art.50, paragraph 1) for food intended for human consumption and for animal feed, with the aim of ensuring the protection of public, animal and environmental health. The purpose of the Rapid Alert System for Food and Feed (RASFF) is to provide the control authorities with the means of exchanging information on the measures taken to ensure food safety. This system allows for a rapid intervention following the discovery of food or feed already placed on the market and which represent, directly or indirectly, a serious risk for human, animal or environmental health. METHODS: Our work intends to examine all alert and information notified to the Hygiene Department of Food and Nutrition of what was formerly NA3 LHU in the last 5 years (2008-2012), and is now Naples 2 North LHU, bearing in mind that, according to regional law 16/2008 (10), the Local Health Units in Campania have been redefined. The types of risk regarding the food subject of the alerts received are: chemical, physical and biological. Food frauds (adulteration, counterfeiting, sophistication and alteration) and the poor state of preservation were considered separately. RESULTS: Out of 146 cases of non-conformity reported, 87 involved chemical risk, 28 biological risk and 17 included foreign bodies; there were also 7 food frauds and 1 case of poor state of preservation. As for the origin, the food subject of non-conformity were for the most part (61,64%) of national origin, while 34.24% came from abroad. Of these, about 66% were of non-EU origin. CONCLUSIONS: The experience gained during the period from 2008 to 2012 allows us to state that the information flow has been improved allowing local services that have been assigned the control to act more rapidly. A critical issue sometimes remains concerning the completeness of the given data, above all regarding the type of risk that, when well reported, provides a valuable contribution to the success of a comprehensive and responsible risk management programme. The encouraging fact that emerges from this study, however, is that, despite the premises made about the characteristics of the area examined, the number of alerts we received involving production sites located in the area of the LHU jurisdiction is less than what we might have expected.


Assuntos
Inocuidade dos Alimentos , Ração Animal , Animais , União Europeia , Alimentos , Indústria Alimentícia/legislação & jurisprudência , Sistemas de Informação em Saúde/legislação & jurisprudência , Sistemas de Informação em Saúde/organização & administração , Humanos , Fatores de Tempo
16.
J Sports Med Phys Fitness ; 53(1): 17-26, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23470907

RESUMO

AIM: We propose a method to estimate O2 deficit (DefO2) during supramaximal exercise based on the analysis of gas exchanges. METHODS: We determined in 14 male subjects breath-by-breath ∙VO2 at the onset of step exercise of moderate and supramaximal intensities. ∙VO2 response during moderate-intensity exercise was fitted as a bi-exponential model. Third, we modelled a theoretical ∙VO2 kinetics during supramaximal exercise assuming that it conformed to the ∙VO2 kinetics measured during moderate-intensity exercise and tended towards a ∙VO2 equal to that hypothetically elicited by the workload. The difference between the O2 volume that would have been consumed in the hypothetical condition and that actually taken up during exercise yielded the lactacid fraction of DefO2. Finally, the difference between the estimated total energy requirement and the theoretical O2 volume consumed by the subject yielded in the alactacid fraction of total DefO2. RESULTS: Total DefO2 was 77.6 mL O2 kg-1; its anaerobic alactic and lactic fractions amounted to 38.5 and 39.1 mL O2 kg-1, respectively. The latter did not differ significantly from the value calculated independently from the peak increase in lactate concentration during supramaximal exercise times the energy equivalent of lactate. CONCLUSIONS: These results suggest that supramaximal DefO2 and its components may be estimated from an analysis of gas exchange kinetics. In addition, they are consistent with the view that the mechanism regulating muscular O2 uptake is regulated by the muscular concentration of putative metabolites.


Assuntos
Ciclismo/fisiologia , Teste de Esforço , Ácido Láctico/sangue , Consumo de Oxigênio/fisiologia , Adulto , Metabolismo Energético/fisiologia , Humanos , Modelos Lineares , Masculino , Modelos Biológicos
17.
J Sports Med Phys Fitness ; 53(4): 396-402, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23828287

RESUMO

AIM: The aims of this paper were: 1) to evaluate the feasibility of test for evaluating physical fitness (PF) in patients with anorexia nervosa (AN); 2) to investigate the effects of nutritional rehabilitation in this population of patients; and 3) to compare their level of fitness scores (at baseline and after weight restoration) with an age-matched healthy control group. METHODS: PF was assessed with an adapted version of the Eurofit Physical Fitness Test Battery (EPFTB) administered to 37 consecutive female AN patients, at baseline and after weight restoration, and to 57 healthy age-matched females. RESULTS: The inpatient treatment, based on cognitive behavior therapy, was associated with a significant improvement in BMI (from 14.5±1.5 to 18.8±1.1, P<0.001) and in 5 out of 6 EPFTB tests (P<0.05) in the AN group. However, both in pre and post, AN patients showed significant lower EPFTB than the control group (all P<0.001) with the exception of the Sit-Up score. CONCLUSION: Results indicated that PF is lower in AN patients than in controls both at baseline and after weight restoration. Future studies should evaluate if the inclusion of an individualized health-enhancing physical activity program might improve the restoration of physical fitness.


Assuntos
Anorexia Nervosa/reabilitação , Peso Corporal/fisiologia , Aptidão Física/fisiologia , Recuperação de Função Fisiológica , Adolescente , Adulto , Anorexia Nervosa/fisiopatologia , Índice de Massa Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Adulto Jovem
18.
Eur Phys J C Part Fields ; 82(7): 599, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35821975

RESUMO

The selection of low-radioactive construction materials is of the utmost importance for rare-event searches and thus critical to the XENONnT experiment. Results of an extensive radioassay program are reported, in which material samples have been screened with gamma-ray spectroscopy, mass spectrometry, and 222 Rn emanation measurements. Furthermore, the cleanliness procedures applied to remove or mitigate surface contamination of detector materials are described. Screening results, used as inputs for a XENONnT Monte Carlo simulation, predict a reduction of materials background ( ∼ 17%) with respect to its predecessor XENON1T. Through radon emanation measurements, the expected 222 Rn activity concentration in XENONnT is determined to be 4.2 ( - 0.7 + 0.5 )  µ Bq/kg, a factor three lower with respect to XENON1T. This radon concentration will be further suppressed by means of the novel radon distillation system.

19.
Eur J Appl Physiol ; 111(3): 367-78, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20428884

RESUMO

The energy cost to swim a unit distance (C(sw)) is given by the ratio E/v where E is the net metabolic power and v is the swimming speed. The contribution of the aerobic and anaerobic energy sources to E in swimming competitions is independent of swimming style, gender or skill and depends essentially upon the duration of the exercise. C(sw) is essentially determined by the hydrodynamic resistance (W(d)): the higher W(d) the higher C(sw); and by the propelling efficiency (η(P)): the higher η(P) the lower C(sw). Hence, all factors influencing W(d) and/or η(P) result in proportional changes in C(sw). Maximal metabolic power E max and C(sw) are the main determinants of swimming performance; an improvement in a subject's best performance time can more easily be obtained by a reduction of C sw) rather than by an (equal) increase in E max (in either of its components, aerobic or anaerobic). These sentences, which constitute a significant contribution to today's knowledge about swimming energetics, are based on the studies that Professor Pietro Enrico di Prampero and his co-workers carried out since the 1970s. This paper is devoted to examine how this body of work helped to improve our understanding of this fascinating mode of locomotion.


Assuntos
Metabolismo Energético/fisiologia , Natação/fisiologia , Fenômenos Biomecânicos/fisiologia , Teste de Esforço/história , História do Século XX , Humanos , Hidrodinâmica , Modelos Biológicos , Modelos Teóricos , Torque
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA