Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
1.
Phys Rev Lett ; 130(5): 051802, 2023 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-36800478

RESUMO

The inclusive electron neutrino charged-current cross section is measured in the NOvA near detector using 8.02×10^{20} protons-on-target in the NuMI beam. The sample of GeV electron neutrino interactions is the largest analyzed to date and is limited by ≃17% systematic rather than the ≃7.4% statistical uncertainties. The double-differential cross section in final-state electron energy and angle is presented for the first time, together with the single-differential dependence on Q^{2} (squared four-momentum transfer) and energy, in the range 1 GeV≤E_{ν}<6 GeV. Detailed comparisons are made to the predictions of the GENIE, GiBUU, NEUT, and NuWro neutrino event generators. The data do not strongly favor a model over the others consistently across all three cross sections measured, though some models have especially good or poor agreement in the single differential cross section vs Q^{2}.

2.
Phys Rev Lett ; 127(20): 201801, 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34860065

RESUMO

This Letter reports results from the first long-baseline search for sterile antineutrinos mixing in an accelerator-based antineutrino-dominated beam. The rate of neutral-current interactions in the two NOvA detectors, at distances of 1 and 810 km from the beam source, is analyzed using an exposure of 12.51×10^{20} protons-on-target from the NuMI beam at Fermilab running in antineutrino mode. A total of 121 of neutral-current candidates are observed at the far detector, compared to a prediction of 122±11(stat.)±15(syst.) assuming mixing only between three active flavors. No evidence for ν[over ¯]_{µ}→ν[over ¯]_{s} oscillation is observed. Interpreting this result within a 3+1 model, constraints are placed on the mixing angles θ_{24}<25° and θ_{34}<32° at the 90% C.L. for 0.05 eV^{2}≤Δm_{41}^{2}≤0.5 eV^{2}, the range of mass splittings that produces no significant oscillations at the near detector. These are the first 3+1 confidence limits set using long-baseline accelerator antineutrinos.

3.
Phys Rev Lett ; 123(15): 151803, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31702305

RESUMO

The NOvA experiment has seen a 4.4σ signal of ν[over ¯]_{e} appearance in a 2 GeV ν[over ¯]_{µ} beam at a distance of 810 km. Using 12.33×10^{20} protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27 ν[over ¯]_{µ}→ν[over ¯]_{e} candidates with a background of 10.3 and 102 ν[over ¯]_{µ}→ν[over ¯]_{µ} candidates. This new antineutrino data are combined with neutrino data to measure the parameters |Δm_{32}^{2}|=2.48_{-0.06}^{+0.11}×10^{-3} eV^{2}/c^{4} and sin^{2}θ_{23} in the ranges from (0.53-0.60) and (0.45-0.48) in the normal neutrino mass hierarchy. The data exclude most values near δ_{CP}=π/2 for the inverted mass hierarchy by more than 3σ and favor the normal neutrino mass hierarchy by 1.9σ and θ_{23} values in the upper octant by 1.6σ.

4.
Phys Rev Lett ; 118(23): 231801, 2017 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-28644674

RESUMO

Results are reported from an improved measurement of ν_{µ}→ν_{e} transitions by the NOvA experiment. Using an exposure equivalent to 6.05×10^{20} protons on target, 33 ν_{e} candidates are observed with a background of 8.2±0.8 (syst.). Combined with the latest NOvA ν_{µ} disappearance data and external constraints from reactor experiments on sin^{2}2θ_{13}, the hypothesis of inverted mass hierarchy with θ_{23} in the lower octant is disfavored at greater than 93% C.L. for all values of δ_{CP}.

5.
Phys Rev Lett ; 118(15): 151802, 2017 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-28452513

RESUMO

This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure of 6.05×10^{20} protons on target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal θ_{23} mixing (θ_{23}=π/4). Assuming the normal mass hierarchy, we find Δm_{32}^{2}=(2.67±0.11)×10^{-3} eV^{2} and sin^{2}θ_{23} at the two statistically degenerate values 0.404_{-0.022}^{+0.030} and 0.624_{-0.030}^{+0.022}, both at the 68% confidence level. Our data disfavor the maximal mixing scenario with 2.6σ significance.

6.
Phys Rev Lett ; 116(15): 151806, 2016 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-27127961

RESUMO

We report results from the first search for ν_{µ}→ν_{e} transitions by the NOvA experiment. In an exposure equivalent to 2.74×10^{20} protons on target in the upgraded NuMI beam at Fermilab, we observe 6 events in the Far Detector, compared to a background expectation of 0.99±0.11(syst) events based on the Near Detector measurement. A secondary analysis observes 11 events with a background of 1.07±0.14(syst). The 3.3σ excess of events observed in the primary analysis disfavors 0.1π<δ_{CP}<0.5π in the inverted mass hierarchy at the 90% C.L.

7.
Biomed Res Int ; 2014: 185265, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24995273

RESUMO

BACKGROUND: The term "paraduodenal pancreatitis" (PP) was proposed as a synonym for duodenal dystrophy (DD) and groove pancreatitis, but it is still unclear what organ PP originates from and how to treat it properly. OBJECTIVE: To assess the results of different types of treatment for PP. METHOD: Prospective analysis of 62 cases of PP (2004-2013) with histopathology of 40 specimens was performed; clinical presentation was assessed and the results of treatment were recorded. RESULTS: Preoperative diagnosis was correct in all the cases except one (1.9%). Patients presented with abdominal pain (100%), weight loss (76%), vomiting (30%), and jaundice (18%). CT, MRI, and endoUS were the most useful diagnostic modalities. Ten patients were treated conservatively, 24 underwent pancreaticoduodenectomies (PD), pancreatico- and cystoenterostomies (8), Nakao procedures (5), duodenum-preserving pancreatic head resections (5), and 10 pancreas-preserving duodenal resections (PPDR) without mortality. Full pain control was achieved after PPRDs in 83%, after PDs in 85%, and after PPPH resections and draining procedures in 18% of cases. Diabetes mellitus developed thrice after PD. CONCLUSIONS: PD is the main surgical option for PP treatment at present; early diagnosis makes PPDR the treatment of choice for PP; efficacy of PPDR for DD treatment provides proof that so-called PP is an entity of duodenal, but not "paraduodenal," origin.


Assuntos
Duodenopatias/cirurgia , Pâncreas/cirurgia , Pancreaticoduodenectomia , Pancreatite/cirurgia , Adulto , Idoso , Alcoolismo/patologia , Duodenopatias/diagnóstico por imagem , Duodenopatias/patologia , Duodeno/patologia , Endoscopia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Pâncreas/diagnóstico por imagem , Pâncreas/patologia , Pancreatite/diagnóstico por imagem , Pancreatite/patologia , Radiografia
8.
Phys Rev Lett ; 112(23): 231801, 2014 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-24972195

RESUMO

We present measurements of ν(µ) charged-current cross section ratios on carbon, iron, and lead relative to a scintillator (CH) using the fine-grained MINERvA detector exposed to the NuMI neutrino beam at Fermilab. The measurements utilize events of energies 2

9.
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.

10.
Phys Rev Lett ; 111(2): 022501, 2013 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-23889388

RESUMO

We have isolated ν(µ) charged-current quasielastic (QE) interactions occurring in the segmented scintillator tracking region of the MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the flux-averaged differential cross section, dσ/dQ², and compare to several theoretical models of QE scattering. Good agreement is obtained with a model where the nucleon axial mass, M(A), is set to 0.99 GeV/c² but the nucleon vector form factors are modified to account for the observed enhancement, relative to the free nucleon case, of the cross section for the exchange of transversely polarized photons in electron-nucleus scattering. Our data at higher Q² favor this interpretation over an alternative in which the axial mass is increased.

11.
Phys Rev Lett ; 111(2): 022502, 2013 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-23889389

RESUMO

We report a study of ν(µ) charged-current quasielastic events in the segmented scintillator inner tracker of the MINERvA experiment running in the NuMI neutrino beam at Fermilab. The events were selected by requiring a µ- and low calorimetric recoil energy separated from the interaction vertex. We measure the flux-averaged differential cross section, dσ/dQ², and study the low energy particle content of the final state. Deviations are found between the measured dσ/dQ² and the expectations of a model of independent nucleons in a relativistic Fermi gas. We also observe an excess of energy near the vertex consistent with multiple protons in the final state.

13.
Khirurgiia (Mosk) ; (2): 11-4, 2011.
Artigo em Russo | MEDLINE | ID: mdl-21378700

RESUMO

During the period between 1982 and 2007 years, 125 patients had been simultaneously operated on the infrarenal atherosclerotic aortic aneurism (aorto-femoral by-pass) and other organs. 86 of them overcame simultaneous surgery considering vascular interventions, the rest 39 had been operated on general surgical and oncologic diseases of abdomen. The acquired results were satisfactory and proved the reasonability of simultaneous operations by aortic aneurism.


Assuntos
Aorta Abdominal , Aneurisma da Aorta Abdominal/cirurgia , Cirurgia Geral/métodos , Neoplasias/cirurgia , Padrões de Prática Médica , Procedimentos Cirúrgicos Vasculares , Idoso , Idoso de 80 Anos ou mais , Aorta Abdominal/patologia , Aorta Abdominal/cirurgia , Aneurisma da Aorta Abdominal/complicações , Aneurisma da Aorta Abdominal/patologia , Aneurisma da Aorta Abdominal/fisiopatologia , Administração de Caso/normas , Procedimentos Clínicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/complicações , Medição de Risco , Procedimentos Cirúrgicos Operatórios , Fatores de Tempo , Resultado do Tratamento
14.
Khirurgiia (Mosk) ; (8): 16-23, 2010.
Artigo em Russo | MEDLINE | ID: mdl-20823815

RESUMO

Two patients with cystic dystrophy of duodenum and chronic inflammation of duodenally ectopic pancreatic tissue were successfully operated on. Both cases clinically demonstrated abdominal pain and duodenal obstruction. Absence of substantial tissue changes in "main" pancreas allowed execution of pancreas-preserving operation. Thus, subtotal duodenectomy was performed in the first patient. The second patient had resection of vertical branch of the duodenum with intestinal fragment replacement. Extensive periorganic fibrosis in both cases substantially complicated verification of anatomic structures and dissection.


Assuntos
Coristoma/cirurgia , Ducto Colédoco/cirurgia , Cistos/cirurgia , Duodenite/cirurgia , Ductos Pancreáticos , Pancreaticoduodenectomia/métodos , Adulto , Cistos/diagnóstico por imagem , Duodenite/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Tomografia Computadorizada por Raios X
15.
Angiol Sosud Khir ; 16(3): 118-23, 2010.
Artigo em Russo | MEDLINE | ID: mdl-21280302

RESUMO

The authors have retrospectively studied the outcomes of surgical management of 421 patients diagnosed with infrarenal atherosclerotic variants of an abdominal aortic aneurysm (AAA) operated on over the period from 1982 to 2007. Of these, there were a total of 389 (92.4%) patients operated on electively, with the remaining 32 (7.6%) patients operated on expeditiously. 264 (67.9%) patients had only been subjected to resection of the aneurysm with linear or bifurcation prosthetic repair of the aorta, 86 (22.1%) endured resection of the aneurysm in a combination with correction of blood flow in other arterial basins, and 39 (10%) patients parallel to AAA resection sustained operations for other surgical and oncological diseases. The authors analysed the effect of comorbidities, the patients' age, AAA size, duration of surgery and the volume of blood loss on the outcomes of surgical treatment. Also studied were the immediate outcomes of surgical treatment, with the remote results followed up in 427 patients having endured AAA resection. The obtained findings confirm a promising nature of combined and concomitant operations in AAA.


Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Prótese Vascular , Neoplasias do Ceco/cirurgia , Colecistectomia/métodos , Colelitíase/cirurgia , Colectomia/métodos , Idoso , Idoso de 80 Anos ou mais , Aneurisma da Aorta Abdominal/complicações , Neoplasias do Ceco/complicações , Colelitíase/complicações , Evolução Fatal , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade
16.
Klin Med (Mosk) ; 86(1): 58-61, 2008.
Artigo em Russo | MEDLINE | ID: mdl-18326288

RESUMO

The purpose of the investigation was to assess the clinical significance of ultrasonography for differential diagnostics between acute inflammatory and tumorous lesions of the neck. One hundred and eighty-six patients with soft-tissue lesions of the neck aged 18 to 74 (mean age 31.45 +/- 8.39 years), 95 (51%) males and 91 (49%) females were examined. Basing on clinical and ultrasonographic examination, the patients were divided into two groups: 149 or 80% patients with acute inflammatory lesions (Group 1), and 37 or 20% patients with tumorous lesions (Group 2). Thirty-four of the 149 Group 1 patients (22.82%) had lymphadenitis, 30 (20.13%) had soft tissue infiltrates, 13 (8.72%) had abscesses, 19 (12.72%) had phlegmons, 32 (21.48%) had acute inflammatory changes in the major salivary glands, 3 (2.01%) had teratomas with signs of inflammation, and 17 (11.41%) patients had inflammatory changes in the tumors. Of 37 patients with tumorous lesions, 16 (43.2%) had salivary gland tumors, 12 (32.4%) had metastases in the lymphatic nodes, and 9 (24.3%) had neurofibromatosis. Soft tissue ultrasonography was performed using Sonos-5500 and Image-Point ultrasound scanners with 7.5 MHz sensors (Hewlett-Packard, USA), Logio-pro, Uoluson-730 Expert (General Electric, USA), and Premium Edition (ACUSON Antares, Siemens, Germany) with 5 to 13 MHz wide-frequency sensors. Visualization was performed in B-modes using tissue harmonics, color duplex scanning, Sie Scape panoramic visualization, contrast visualization and Sight 4D and 3D-Scape modes. The results of ultrasonography were analyzed taking into account additional methods such as computed and magnetic resonance tomography, intraoperative findings, the results of puncture biopsy, histological, morphological, and bacteriological studies. The study demonstrates that ultrasonography is the method of choice, which is in some cases enough to establish a diagnosis of an acute inflammatory disease or a tumorous formation of various localizations in the neck.


Assuntos
Celulite (Flegmão)/diagnóstico , Neoplasias de Cabeça e Pescoço/diagnóstico , Linfadenite/diagnóstico , Neurofibromatoses/diagnóstico , Adolescente , Adulto , Idoso , Celulite (Flegmão)/diagnóstico por imagem , Diagnóstico Diferencial , Feminino , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Humanos , Linfadenite/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Pescoço , Neurofibromatoses/diagnóstico por imagem , Ultrassonografia
17.
Klin Med (Mosk) ; 85(3): 43-6, 2007.
Artigo em Russo | MEDLINE | ID: mdl-17523404

RESUMO

One of modern and highly effective methods of diagnostics and differential diagnostics of infected pancreonecrosis is chromatographic technique, which allows for identification of anaerobic non-clostridial infection in the foci of pancreatic destruction by the presence of volatile fatty acids, the specific end products of anaerobic bacterial metabolism. Gas chromatography (GC) - mass spectrometry (MS) also make it possible to detect in peripheral blood of patients with pancreatitis certain metabolites (di-, polyamines, and aromatic amines) that are markers of tissue (protein structure) disintegration and the degree of pancreonecrosis, which is a valuable indicator of the degree of pancreonecrosis. The presence, according to GC - MS analysis, of natural inhibitors of transamidinase (compounds of thiourea and its metabolites, the group of mercaptopurines and mercapto-derivates of imidazole) in peripheral blood at the maximum level--0.71 to 0.78 mmol/l on days 7 to 10 upon the onset of the disease--is a prognostically favorable criterion. At the same time, the presence of the maximum level of anaerobic non-clostridial infection metabolite in peripheral blood 1.12 to 1.31 mmol/l on days 7 to 10 upon the onset of the disease--is prognostically infavorable. These chromatographic criteria in combination with clinical manifestations can be considered indications to surgical treatment of infected pancreonecrosis, and the prognosis of the disease can be based on them.


Assuntos
Ácidos Graxos Voláteis/análise , Pancreatite Necrosante Aguda/diagnóstico , Amidinotransferases/antagonistas & inibidores , Amidinotransferases/metabolismo , Bactérias Anaeróbias/isolamento & purificação , Bactérias Anaeróbias/metabolismo , Cromatografia Gasosa/métodos , Inibidores Enzimáticos/sangue , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Pâncreas/metabolismo , Pâncreas/microbiologia , Pâncreas/patologia , Pancreatite Necrosante Aguda/microbiologia , Poliaminas/sangue , Prognóstico
18.
Khirurgiia (Mosk) ; (7): 15-8, 2004.
Artigo em Russo | MEDLINE | ID: mdl-15340322

RESUMO

Dynamics of effective and general concentration of albumins and middle-size molecules in blood plasma of patients with severe pancreonecrosis is described. Significant differences of these data in operated and non-operated patients are revealed. A negative correlation between severity of pancreatic necrosis and concentrations of albumins, and a direct correlation between necrotic lesion and concentration of middle-size molecules in blood plasma were demonstrated. The above parameters are important for assessment of treatment efficacy, prognosis of postoperative complications and determination of indications to sanated relaparotomies in patients with pancreonecrosis.


Assuntos
Proteínas Sanguíneas/análise , Pancreatite Necrosante Aguda/sangue , Adulto , Idoso , Feminino , Homeostase , Humanos , Masculino , Pessoa de Meia-Idade , Pancreatite Necrosante Aguda/diagnóstico , Pancreatite Necrosante Aguda/cirurgia , Prognóstico , Albumina Sérica/análise
19.
Anesteziol Reanimatol ; (5): 50-5, 2003.
Artigo em Russo | MEDLINE | ID: mdl-14671912

RESUMO

The modern technique of postoperative analgesia after extensive and traumatic surgical interventions presupposes the administration, apart from opiates, a variety of preparations inhibiting the biological activity of substances (prostaglandins, kinins, TNF, leukotrienes, etc.), i.e. mediators of the systemic-inflammatory response, which are of the key importance in modeling the postoperative pain. The paper deals with the specificity of postoperative analgesia at different stages of surgical treatment of patients with destructive pancreatitis (DP). The surgical tactics in DP envisages a primary revision of the abdominal cavity, necrectomy and omentobursostomy with subsequent multi ple stage-based sanations of the abdominal cavity. The above surgical technique in DP is traumatic and long-lasting with the in-hospital treatment amounting on the average to 46.8 +/- 3.2 days. The entire postoperative period in DP patients is divided into 4 stages with each stage having a certain specific level of intoxication, systemic-inflammatory response and of pain syndrome. An analgesia scheme, based on epidural anesthesia combined with the inhibitors of kinin-genesis (inhitril, contrical) of prostaglandin-genesis (ketorol of xefocam) and of a synthetic analogue of leu-enkephalines (daralgin). A specific combination of analgetics was typical of each treatment stage.


Assuntos
Cavidade Abdominal/cirurgia , Analgesia Epidural/métodos , Analgésicos/uso terapêutico , Dor Pós-Operatória/prevenção & controle , Pancreatite Necrosante Aguda/cirurgia , Adulto , Idoso , Analgésicos/administração & dosagem , Analgésicos Opioides/administração & dosagem , Analgésicos Opioides/uso terapêutico , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/uso terapêutico , Feminino , Humanos , Infusões Intravenosas , Injeções Intramusculares , Masculino , Pessoa de Meia-Idade , Inibidores de Proteases/administração & dosagem , Inibidores de Proteases/uso terapêutico
20.
Lik Sprava ; (4): 89-92, 2001.
Artigo em Russo | MEDLINE | ID: mdl-11692741

RESUMO

Shown in the paper is a possibility of surgical correction of disturbances in the intestinal phase of gastric secretion in treating peptic ulcer and its complications which are encountered in an overwhelming majority of patients. Sympathectomy of relevant vascular trees is regarded as a pathogenetically validated procedure as is correction of duodenal motility combined with selective proximal vagotomy and excision of the ulcer. It is shown that truncal and selective vagotomy can aggravate the existing disorders of the intestinal phase of gastric secretion.


Assuntos
Ácido Gástrico/metabolismo , Úlcera Péptica/cirurgia , Refluxo Gastroesofágico/complicações , Motilidade Gastrointestinal , Humanos , Úlcera Péptica/complicações , Úlcera Péptica/fisiopatologia , Simpatectomia , Vagotomia Gástrica Proximal , Vagotomia Troncular/efeitos adversos , Nervo Vago/cirurgia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA