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1.
Nature ; 614(7946): 48-53, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36725994

RESUMO

Scattering of high energy particles from nucleons probes their structure, as was done in the experiments that established the non-zero size of the proton using electron beams1. The use of charged leptons as scattering probes enables measuring the distribution of electric charges, which is encoded in the vector form factors of the nucleon2. Scattering weakly interacting neutrinos gives the opportunity to measure both vector and axial vector form factors of the nucleon, providing an additional, complementary probe of their structure. The nucleon transition axial form factor, FA, can be measured from neutrino scattering from free nucleons, νµn → µ-p and [Formula: see text], as a function of the negative four-momentum transfer squared (Q2). Up to now, FA(Q2) has been extracted from the bound nucleons in neutrino-deuterium scattering3-9, which requires uncertain nuclear corrections10. Here we report the first high-statistics measurement, to our knowledge, of the [Formula: see text] cross-section from the hydrogen atom, using the plastic scintillator target of the MINERvA11 experiment, extracting FA from free proton targets and measuring the nucleon axial charge radius, rA, to be 0.73 ± 0.17 fm. The antineutrino-hydrogen scattering presented here can access the axial form factor without the need for nuclear theory corrections, and enables direct comparisons with the increasingly precise lattice quantum chromodynamics computations12-15. Finally, the tools developed for this analysis and the result presented are substantial advancements in our capabilities to understand the nucleon structure in the weak sector, and also help the current and future neutrino oscillation experiments16-20 to better constrain neutrino interaction models.

2.
Phys Rev Lett ; 131(5): 051801, 2023 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-37595210

RESUMO

MINERvA has measured the ν_{µ}-induced coherent π^{+} cross section simultaneously in hydrocarbon (CH), graphite (C), iron (Fe), and lead (Pb) targets using neutrinos from 2 to 20 GeV. The measurements exceed the predictions of the Rein-Sehgal and Berger-Sehgal PCAC based models at multi-GeV ν_{µ} energies and at produced π^{+} energies and angles, E_{π}>1 GeV and θ_{π}<10°. Measurements of the cross-section ratios of Fe and Pb relative to CH reveal the effective A scaling to increase from an approximate A^{1/3} scaling at few GeV to an A^{2/3} scaling for E_{ν}>10 GeV.

3.
Phys Rev Lett ; 130(16): 161801, 2023 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-37154647

RESUMO

This Letter presents the first simultaneous measurement of the quasielasticlike neutrino-nucleus cross sections on C, water, Fe, Pb, and scintillator (hydrocarbon or CH) as a function of longitudinal and transverse muon momentum. The ratio of cross sections per nucleon between Pb and CH is always above unity and has a characteristic shape as a function of transverse muon momentum that evolves slowly as a function of longitudinal muon momentum. The ratio is constant versus longitudinal momentum within uncertainties above a longitudinal momentum of 4.5 GeV/c. The cross section ratios to CH for C, water, and Fe remain roughly constant with increasing longitudinal momentum, and the ratios between water or C to CH do not have any significant deviation from unity. Both the overall cross section level and the shape for Pb and Fe as a function of transverse muon momentum are not reproduced by current neutrino event generators. These measurements provide a direct test of nuclear effects in quasielasticlike interactions, which are major contributors to long-baseline neutrino oscillation data samples.

4.
Phys Rev Lett ; 125(13): 131802, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-33034464

RESUMO

We report the final measurement of the neutrino oscillation parameters Δm_{32}^{2} and sin^{2}θ_{23} using all data from the MINOS and MINOS+ experiments. These data were collected using a total exposure of 23.76×10^{20} protons on target producing ν_{µ} and ν[over ¯]_{µ} beams and 60.75 kt yr exposure to atmospheric neutrinos. The measurement of the disappearance of ν_{µ} and the appearance of ν_{e} events between the Near and Far detectors yields |Δm_{32}^{2}|=2.40_{-0.09}^{+0.08}(2.45_{-0.08}^{+0.07})×10^{-3} eV^{2} and sin^{2}θ_{23}=0.43_{-0.04}^{+0.20}(0.42_{-0.03}^{+0.07}) at 68% C.L. for normal (inverted) hierarchy.

5.
Phys Rev Lett ; 121(2): 022504, 2018 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-30085714

RESUMO

Final-state kinematic imbalances are measured in mesonless production of ν_{µ}+A→µ^{-}+p+X in the MINERvA tracker. Initial- and final-state nuclear effects are probed using the direction of the µ^{-}-p transverse momentum imbalance and the initial-state momentum of the struck neutron. Differential cross sections are compared to predictions based on current approaches to medium modeling. These models underpredict the cross section at intermediate intranuclear momentum transfers that generally exceed the Fermi momenta. As neutrino interaction models need to correctly incorporate the effect of the nucleus in order to predict neutrino energy resolution in oscillation experiments, this result points to a region of phase space where additional cross section strength is needed in current models, and demonstrates a new technique that would be suitable for use in fine-grained liquid argon detectors where the effect of the nucleus may be even larger.

6.
Phys Rev Lett ; 120(22): 221805, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29906174

RESUMO

We report on multinucleon effects in low momentum transfer (<0.8 GeV/c) antineutrino interactions on plastic (CH) scintillator. These data are from the 2010-2011 antineutrino phase of the MINERvA experiment at Fermilab. The hadronic energy spectrum of this inclusive sample is well described when a screening effect at a low energy transfer and a two-nucleon knockout process are added to a relativistic Fermi gas model of quasielastic, Δ resonance, and higher resonance processes. In this analysis, model elements introduced to describe previously published neutrino results have quantitatively similar benefits for this antineutrino sample. We present the results as a double-differential cross section to accelerate the investigation of alternate models for antineutrino scattering off nuclei.

7.
Phys Rev Lett ; 119(1): 011802, 2017 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-28731762

RESUMO

Neutral-current production of K^{+} by atmospheric neutrinos is a background in searches for the proton decay p→K^{+}ν[over ¯]. Reactions such as νp→νK^{+}Λ are indistinguishable from proton decays when the decay products of the Λ are below detection threshold. Events with K^{+} are identified in MINERvA by reconstructing the timing signature of a K^{+} decay at rest. A sample of 201 neutrino-induced neutral-current K^{+} events is used to measure differential cross sections with respect to the K^{+} kinetic energy, and the non-K^{+} hadronic visible energy. An excess of events at low hadronic visible energy is observed relative to the prediction of the neut event generator. Good agreement is observed with the cross section prediction of the genie generator. A search for photons from π^{0} decay, which would veto a neutral-current K^{+} event in a proton decay search, is performed, and a 2σ deficit of detached photons is observed relative to the genie prediction.

8.
Phys Rev Lett ; 119(8): 082001, 2017 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-28952766

RESUMO

Charged-current ν_{µ} interactions on carbon, iron, and lead with a final state hadronic system of one or more protons with zero mesons are used to investigate the influence of the nuclear environment on quasielasticlike interactions. The transferred four-momentum squared to the target nucleus, Q^{2}, is reconstructed based on the kinematics of the leading proton, and differential cross sections versus Q^{2} and the cross-section ratios of iron, lead, and carbon to scintillator are measured for the first time in a single experiment. The measurements show a dependence on the atomic number. While the quasielasticlike scattering on carbon is compatible with predictions, the trends exhibited by scattering on iron and lead favor a prediction with intranuclear rescattering of hadrons accounted for by a conventional particle cascade treatment. These measurements help discriminate between different models of both initial state nucleons and final state interactions used in the neutrino oscillation experiments.

9.
Phys Rev Lett ; 117(6): 061802, 2016 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-27541459

RESUMO

Neutrino-induced charged-current coherent kaon production ν_{µ}A→µ^{-}K^{+}A is a rare, inelastic electroweak process that brings a K^{+} on shell and leaves the target nucleus intact in its ground state. This process is significantly lower in rate than the neutrino-induced charged-current coherent pion production because of Cabibbo suppression and a kinematic suppression due to the larger kaon mass. We search for such events in the scintillator tracker of MINERvA by observing the final state K^{+}, µ^{-}, and no other detector activity, and by using the kinematics of the final state particles to reconstruct the small momentum transfer to the nucleus, which is a model-independent characteristic of coherent scattering. We find the first experimental evidence for the process at 3σ significance.

10.
Phys Rev Lett ; 117(11): 111801, 2016 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-27661679

RESUMO

The MINERvA experiment observes an excess of events containing electromagnetic showers relative to the expectation from Monte Carlo simulations in neutral-current neutrino interactions with mean beam energy of 4.5 GeV on a hydrocarbon target. The excess is characterized and found to be consistent with neutral-current π^{0} production with a broad energy distribution peaking at 7 GeV and a total cross section of 0.26±0.02(stat.)±0.08(sys.)×10^{-39} cm^{2}. The angular distribution, electromagnetic shower energy, and spatial distribution of the energy depositions of the excess are consistent with expectations from neutrino neutral-current diffractive π^{0} production from hydrogen in the hydrocarbon target. These data comprise the first direct experimental observation and constraint for a reaction that poses an important background process in neutrino-oscillation experiments searching for ν_{µ} to ν_{e} oscillations.

11.
Phys Rev Lett ; 116(8): 081802, 2016 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-26967410

RESUMO

The first direct measurement of electron neutrino quasielastic and quasielasticlike scattering on hydrocarbon in the few-GeV region of incident neutrino energy has been carried out using the MINERvA detector in the NuMI beam at Fermilab. The flux-integrated differential cross sections in the electron production angle, electron energy, and Q^{2} are presented. The ratio of the quasielastic, flux-integrated differential cross section in Q^{2} for ν_{e} with that of similarly selected ν_{µ}-induced events from the same exposure is used to probe assumptions that underpin conventional treatments of charged-current ν_{e} interactions used by long-baseline neutrino oscillation experiments. The data are found to be consistent with lepton universality and are well described by the predictions of the neutrino event generator GENIE.

12.
Phys Rev Lett ; 113(26): 261802, 2014 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-25615308

RESUMO

Neutrino-induced coherent charged pion production on nuclei νµA→µ(±)π(∓)A is a rare, inelastic interaction in which a small squared four-momentum |t| is transferred to the recoil nucleus, leaving it intact in the reaction. In the scintillator tracker of MINERvA, we remove events with evidence of particles from nuclear breakup and reconstruct |t| from the final-state pion and muon. We select low |t| events to isolate a sample rich in coherent candidates. By selecting low |t| events, we produce a model-independent measurement of the differential cross section for coherent scattering of neutrinos and antineutrinos on carbon. We find poor agreement with the predicted kinematics in neutrino generators used by current oscillation experiments.

13.
Heliyon ; 10(6): e27783, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38524528

RESUMO

Degradation of insulation paper is a key contributor to the failure of power transformers. Insulation degradation accelerates at elevated temperatures, which highlights the potential for better thermal management to prolong life. While several studies have analyzed the benefits of high thermal conductivity oil for reducing temperatures inside a transformer, this study is an initial assessment of the benefits of high thermal conductivity paper on transformer life. Blending particulates with cellulosic fibers offers a pathway for high thermal conductivity paper (with good dielectric properties), which can reduce internal temperatures. Presently, life extensions that can be achieved by the use of such thermally conducting papers were estimated, with the thermal conductivity of the paper being the key parameter under study. The analytical-numerical thermal model used in this study was validated against experimental measurements in a distribution transformer, adding confidence to the utility of the model. This model was then used to provide estimates of hot-spot temperature reduction resulting from the use of papers with higher thermal conductivity than baseline. Transformer life was predicted conventionally by tracking the degree of polymerization of paper over time, based on an Arrhenius model. Results indicate that increasing the thermal conductivity of paper from 0.2 W/mK (baseline) to 1 W/mK reduces the hot spot temperature by 10 °C. While degradation significantly depends on the moisture and oxygen content, the model shows that such a temperature reduction can increase life for all conditions, by as much as a factor of three.

14.
Mayo Clin Proc ; 67(4): 328-33, 1992 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1548947

RESUMO

Although defined formula diets may be useful for initial episodes of Crohn's disease, the effects of these diets on subsequent attacks of Crohn's disease or in conjunction with corticosteroids are unknown. To evaluate these issues, we studied 27 patients in a randomized prospective trial. Ten patients received only prednisone (group I), nine received only a defined formula diet (Vital HN [high nitrogen]) (group II), and eight received a combination of prednisone and Vital HN (group III). At the time of entry into the study, the groups were similar with respect to age, sex, Crohn's Disease Activity Index, previous and current treatments, anatomic site of disease, and nutritional status. After 1 month of treatment, we noted seven successes (70%) and three failures in group I (prednisone only), three successes (33%) and six failures in group II (Vital HN only), and six successes (75%) and two failures in group III (combination therapy). Four patients randomized to receive only Vital HN were unable or unwilling to tolerate the defined formula diet. Of the five patients who were able to take the defined formula diet for 1 month, however, three (60%) were successfully treated. The patients who received prednisone (groups I and III) responded better than did the patients who received only the defined formula diet. These results may be attributable to the use of a nonelemental diet or the treatment of patients who were not experiencing an initial attack of Crohn's disease or who had previously received corticosteroids. The expensive and often poorly tolerated defined formula diets should not be considered as a substitute for standard therapy with corticosteroids in Crohn's disease.


Assuntos
Doença de Crohn/terapia , Alimentos Formulados , Prednisona/uso terapêutico , Adulto , Idoso , Terapia Combinada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
15.
Prog Brain Res ; 134: 471-81, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11702562

RESUMO

Human observers can discriminate two attributes from the same object more efficiently than attributes from two different objects even if the retinal locations of the attributes are the same in the single and dual object cases. The single object advantage challenges the spatial spotlight view of attention and suggests that attentional selection can be object based. We report that the single object advantage is reliably reduced when an object working memory task is performed concurrently, whereas concurrent verbal and spatial working memory tasks have no effect. This selective interference effect provides support for the existence of object-based attentional processes that also contribute to the short-term retention of objects in working memory. These results are consistent with the hypothesis that both attentional and memory subsystems are organized along domain-specific lines, and suggest the importance of attention in rehearsal operations. The contributions of inferior temporal and parietal mechanisms that have been implicated in attending to and remembering objects are considered.


Assuntos
Atenção/fisiologia , Memória/fisiologia , Processos Mentais/fisiologia , Animais , Encéfalo/fisiologia , Humanos , Percepção Visual/fisiologia
16.
Gen Hosp Psychiatry ; 2(1): 41-5, 1980 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7380248

RESUMO

This article reviews the literature on the consultant/consultee relationship within psychiatric liaison nursing. Data on 284 referrals from staff nurses to psychiatric liaison nurses (PLNs) in a teaching hospital are examined to discover whether the nature of the referrals changes with the evolving consultation relationship. Referrals are found to change over time in their specificity, focus, level of sophistication, and kind of PLN involvement requested. Possible explanations for these changes are discussed.


Assuntos
Enfermagem Psiquiátrica , Encaminhamento e Consulta , Hospitais de Ensino , Humanos , Transtornos Mentais/terapia , Relações Enfermeiro-Paciente
17.
J Vet Diagn Invest ; 2(4): 308-11, 1990 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1965637

RESUMO

Polyacrylamide gel electrophoresis was conducted on genomic RNA extracted from rotaviruses detected in diarrheic pigs from conventional swine herds. Ninety samples contained sufficient virus for RNA band visualization and genome classification. Genome profiles were characteristic of typical group A rotaviruses in 67.8% of the 90 samples, of group B rotaviruses in 10.0%, and of group C rotaviruses in 11.1%. In 11.1% of the samples, the presence of more than 11 bands suggested concurrent infection with more than 1 strain of rotavirus. In infections among nursing pigs, 76.4% were group A rotaviruses, 7.4% were group B, 7.4% were group C, and 8.8% were coinfections. In infections among weaned pigs, 40.9% were group A, 18.2% were group B, 22.7% were group C, and 18.2% were coinfections. Coelectrophoresis with prototype OSU and Gottfried strains revealed a great diversity in electropherotype among field strains of rotavirus.


Assuntos
Diarreia/veterinária , RNA Viral/análise , Infecções por Rotavirus/veterinária , Rotavirus/genética , Doenças dos Suínos/microbiologia , Animais , Animais Lactentes , Diarreia/microbiologia , Eletroforese em Gel de Poliacrilamida , Fezes/microbiologia , Conteúdo Gastrointestinal/microbiologia , Rotavirus/classificação , Infecções por Rotavirus/microbiologia , Suínos , Desmame
18.
J Vet Diagn Invest ; 7(4): 456-64, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8580165

RESUMO

Four seronegative adult boars were intranasally inoculated with porcine reproductive and respiratory syndrome virus (PRRSV) isolate VR-2332. Serum and semen were collected 2-3 times weekly for over 100 days postinoculation (DPI). Serum samples were assayed for PRRSV by virus isolation (VI) and a polymerase chain reaction (PCR) and screened for antibodies to PRRSV using the indirect fluorescent antibody (IFA) and virus neutralization (VN) tests. Semen was assayed for PRRSV RNA by PCR. Virus and viral RNA was detected in the serum of all boars within 1 DPI by Vi and/or PCR. However, VI results indicated that viremia was transient and occurred from 1 to 9 DPI. Viral RNA was detected in serum from 1 to 31 DPI. In the acute stage of the infection, PRRSV RNA was detected in serum by PCR prior to the presence of viral RNA in semen. The PRRSV RNA was detected in semen as early as 3 DPI and persisted for 25 DPI in 2 of the boars and 56 and 92 DPI in the remaining 2 boars. Detection of PRRSV RNA in semen occurred 2-8 and 28-35 days prior to the detection of antibodies by IFA and VN, respectively. PRRSV was isolated from the bulbourethral gland of the boar that shed viral RNA in semen for 92 DPI. These results suggest that PRRSV RNA can be detected by PCR in boar serum and semen, and may persist for variable periods of time. Viremia and the serologic status of the boar are not adequate indicators of when PRRSV or PRRSV RNA is being shed in the semen. Preliminary findings also indicated that neither shipping stress nor reinoculation with homologous PRRSV resulted in viremia or viral RNA shedding in semen.


Assuntos
Infecções por Arterivirus/veterinária , Sangue/virologia , Sêmen/virologia , Doenças dos Suínos , Animais , Arterivirus/isolamento & purificação , Infecções por Arterivirus/diagnóstico , Sequência de Bases , Bioensaio/métodos , Primers do DNA , Técnica Indireta de Fluorescência para Anticorpo , Masculino , Dados de Sequência Molecular , Testes de Neutralização , Fases de Leitura Aberta , Especificidade de Órgãos , Reação em Cadeia da Polimerase/métodos , RNA Viral/análise , Suínos , Síndrome , Eliminação de Partículas Virais
19.
Nutr Clin Pract ; 8(1): 43-7, 1993 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8455532

RESUMO

The practice of providing specialized enteral and parenteral nutrition to patients in the home setting has expanded nationwide during the past decade. Accompanying this growth has been an increased need for education of patients, families, and care providers in techniques of administering intravenous and tube feedings safely after discharge from the hospital. To meet this demand for information, written home nutrition support (HNS) education materials have been developed by hospital nutrition support teams, patient education specialists, home care providers, and formula manufacturers. The time and financial costs of developing these materials may be prohibitive in certain institutions that need HNS education resources. A directory of the printed materials available has been compiled to facilitate communication and exchange of HNS education information among institutions. The directory is presented with this article, with important characteristics to consider in the development of HNS education materials.


Assuntos
Nutrição Enteral , Serviços de Assistência Domiciliar , Nutrição Parenteral no Domicílio , Educação de Pacientes como Assunto , Materiais de Ensino , Humanos
20.
Am J Vet Res ; 51(1): 114-7, 1990 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2301809

RESUMO

Cartilage retention strengths of laryngoplasty prostheses were compared in larynges of 2-, 3-, and 4-year-old horses, using doubled polyester and expanded polytetrafluoroethylene prostheses. Bilateral laryngoplasties were performed on each of 15 (seven 2-year-old, two 3-year-old, and six 4-year-old) larynges, which were collected at an abbatoir. Prostheses were secured to a mechanical testing machine, and tension causing arytenoid cartilage abduction was applied, until total failure of the cartilage or prosthesis resulted. Tension caused cricoid cartilage failure in 1 specimen, and muscular process cartilage failure in the remainder. There was no significant effect of age, prosthetic material, or side of prosthesis placement on cartilage retention of the prostheses. Additionally, frequency of multiple load-displacement peaks, indicating partial muscular process failure, was not affected by age or prosthetic material variables.


Assuntos
Cavalos , Cartilagens Laríngeas/fisiologia , Laringe/cirurgia , Próteses e Implantes/veterinária , Fatores Etários , Animais , Cartilagem Aritenoide/fisiologia , Cartilagem Cricoide/fisiologia , Poliésteres , Politetrafluoretileno , Falha de Prótese
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