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1.
Phys Rev Lett ; 127(6): 062003, 2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34420329

RESUMO

We describe an analysis comparing the pp[over ¯] elastic cross section as measured by the D0 Collaboration at a center-of-mass energy of 1.96 TeV to that in pp collisions as measured by the TOTEM Collaboration at 2.76, 7, 8, and 13 TeV using a model-independent approach. The TOTEM cross sections, extrapolated to a center-of-mass energy of sqrt[s]=1.96 TeV, are compared with the D0 measurement in the region of the diffractive minimum and the second maximum of the pp cross section. The two data sets disagree at the 3.4σ level and thus provide evidence for the t-channel exchange of a colorless, C-odd gluonic compound, also known as the odderon. We combine these results with a TOTEM analysis of the same C-odd exchange based on the total cross section and the ratio of the real to imaginary parts of the forward elastic strong interaction scattering amplitude in pp scattering for which the significance is between 3.4σ and 4.6σ. The combined significance is larger than 5σ and is interpreted as the first observation of the exchange of a colorless, C-odd gluonic compound.

2.
Phys Rev Lett ; 124(16): 161802, 2020 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-32383902

RESUMO

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

3.
Phys Rev Lett ; 121(17): 171802, 2018 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-30411920

RESUMO

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3} eV^{2}/c^{4}.

4.
Phys Rev Lett ; 118(15): 151801, 2017 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-28452532

RESUMO

T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beams. The data include all runs from January 2010 to May 2016 and comprise 7.482×10^{20} protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135 µ-like events, and 7.471×10^{20} protons on target in antineutrino mode, which yielded 4 e-like and 66 µ-like events. Reactor measurements of sin^{2}2θ_{13} have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δ_{CP} spans the range (-3.13, -0.39) for normal mass ordering. The CP conservation hypothesis (δ_{CP}=0, π) is excluded at 90% C.L.

5.
Phys Rev Lett ; 117(19): 192501, 2016 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-27858422

RESUMO

We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.

6.
Phys Rev Lett ; 116(18): 181801, 2016 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-27203315

RESUMO

T2K reports its first measurements of the parameters governing the disappearance of ν[over ¯]_{µ} in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ν[over ¯]_{µ} beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ν[over ¯]_{µ} survival probability is expected to be minimal. Using a data set corresponding to 4.01×10^{20} protons on target, 34 fully contained µ-like events were observed. The best-fit oscillation parameters are sin^{2}(θ[over ¯]_{23})=0.45 and |Δm[over ¯]_{32}^{2}|=2.51×10^{-3} eV^{2} with 68% confidence intervals of 0.38-0.64 and 2.26-2.80×10^{-3} eV^{2}, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the ν_{µ} disappearance parameters measured by T2K.

7.
Phys Rev Lett ; 112(6): 061802, 2014 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-24580687

RESUMO

The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm(32)(2) and a CP violating phase δ(CP). In this neutrino oscillation scenario, assuming |Δm(32)(2)|=2.4×10(-3) eV(2), sin(2)θ(23)=0.5, and Δm322>0 (Δm(32)(2)<0), a best-fit value of sin(2)2θ(13)=0.140(-0.032)(+0.038) (0.170(-0.037)(+0.045)) is obtained at δ(CP)=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ(13) from reactor experiments, some values of δ(CP) are disfavored at the 90% C.L.

8.
Phys Rev Lett ; 112(18): 181801, 2014 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-24856687

RESUMO

New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter θ23. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57×10(20) protons on target, T2K has fit the energy-dependent νµ oscillation probability to determine oscillation parameters. The 68% confidence limit on sin(2)(θ23) is 0.514(-0.056)(+0.055) (0.511±0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Δm32(2)=(2.51±0.10)×10(-3) eV(2)/c(4) (inverted hierarchy: Δm13(2)=(2.48±0.10)×10(-3) eV(2)/c(4)). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.

9.
Phys Rev Lett ; 113(24): 241803, 2014 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-25541766

RESUMO

The T2K off-axis near detector ND280 is used to make the first differential cross-section measurements of electron neutrino charged current interactions at energies ∼1 GeV as a function of electron momentum, electron scattering angle, and four-momentum transfer of the interaction. The total flux-averaged ν(e) charged current cross section on carbon is measured to be ⟨σ⟩(ϕ)=1.11±0.10(stat)±0.18(syst)×10⁻³8 cm²/nucleon. The differential and total cross-section measurements agree with the predictions of two leading neutrino interaction generators, NEUT and GENIE. The NEUT prediction is 1.23×10⁻³8 cm²/nucleon and the GENIE prediction is 1.08×10⁻³8 cm²/nucleon. The total ν(e) charged current cross-section result is also in agreement with data from the Gargamelle experiment.

10.
Phys Rev Lett ; 111(1): 012001, 2013 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-23862993

RESUMO

The TOTEM collaboration has measured the proton-proton total cross section at √s=8 TeV using a luminosity-independent method. In LHC fills with dedicated beam optics, the Roman pots have been inserted very close to the beam allowing the detection of ~90% of the nuclear elastic scattering events. Simultaneously the inelastic scattering rate has been measured by the T1 and T2 telescopes. By applying the optical theorem, the total proton-proton cross section of (101.7±2.9) mb has been determined, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections: σ(el)=(27.1±1.4) mb; σ(inel)=(74.7±1.7) mb.

11.
Phys Rev Lett ; 111(26): 262001, 2013 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-24483791

RESUMO

The first double diffractive cross-section measurement in the very forward region has been carried out by the TOTEM experiment at the LHC with a center-of-mass energy of sqrt[s]=7 TeV. By utilizing the very forward TOTEM tracking detectors T1 and T2, which extend up to |η|=6.5, a clean sample of double diffractive pp events was extracted. From these events, we determined the cross section σDD=(116±25) µb for events where both diffractive systems have 4.7<|η|min<6.5.

12.
Phys Rev Lett ; 111(21): 211803, 2013 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-24313479

RESUMO

The T2K Collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to 3.01×10(20) protons on target. In the absence of neutrino oscillations, 205±17 (syst) events are expected to be detected while only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum, assuming three neutrino flavors and normal mass hierarchy yields a best-fit mixing angle sin2(θ23)=0.514±0.082 and mass splitting |Δm(32)(2)|=2.44(-0.15)(+0.17)×10(-3) eV2/c4. Our result corresponds to the maximal oscillation disappearance probability.

13.
Eur Phys J C Part Fields ; 83(9): 782, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37680254

RESUMO

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7(16.3)×1020 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7×1020 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin2θ13 and the impact of priors on the δCP measurement. Both analyses prefer the normal mass ordering and upper octant of sin2θ23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin2θ13 from reactors, sin2θ23=0.561-0.032+0.021 using Feldman-Cousins corrected intervals, and Δm322=2.494-0.058+0.041×10-3eV2 using constant Δχ2 intervals. The CP-violating phase is constrained to δCP=-1.97-0.70+0.97 using Feldman-Cousins corrected intervals, and δCP=0,π is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than 2σ credible level using a flat prior in δCP, and just below 2σ using a flat prior in sinδCP. When the external constraint on sin2θ13 is removed, sin2θ13=28.0-6.5+2.8×10-3, in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

14.
Phys Rev Lett ; 107(4): 041801, 2011 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-21866992

RESUMO

The T2K experiment observes indications of ν(µ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3) eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy.

15.
Clin Endocrinol (Oxf) ; 70(1): 88-95, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19128365

RESUMO

OBJECTIVES: In acromegalic patients, cardiovascular and metabolic comorbidities contribute to enhance mortality. Available data on the lipoprotein profile of these patients are controversial. Our aim was to characterize the lipoprotein profile and emergent biomarkers of cardiovascular disease in active acromegalic patients in comparison with sex- and age-matched healthy controls. PATIENTS: Eighteen patients with active acromegaly and 18 controls were studied. MEASUREMENTS: Glucose levels, hormonal status, lipoprotein profile and C reactive protein (CRP) were evaluated by standardized methods. Cholesteryl ester transfer protein (CETP) and lipoprotein-associated phospholipase A(2 )(Lp-PLA(2)) were measured by radiometric techniques, endothelin-1 and vascular cell adhesion molecule (VCAM)-1 by enzyme-linked immunosorbent assay, and leucocytes CD18, CD49d and CD54 by flow cytometry. RESULTS: After adjusting for body mass index (BMI), acromegalic patients presented a more atherogenic lipoprotein profile, consisting of higher levels of triglycerides and apolipoprotein B and alterations in the ratios which estimate insulin resistance and atherogenic risk. CETP activity was significantly increased in acromegalic patients as compared to controls (168 +/- 17 vs. 141 +/- 30% per ml h, respectively; P < 0.05). Endothelin-1 levels evidenced an increase in the patients' group (0.9 +/- 0.2 vs. 0.7 +/- 0.2 ng/l, respectively; P < 0.01) and showed positive and significant correlations with GH, IGF-1 and IGFBP-3 (r = 0.45, 0.42 and 0.44, respectively; P < 0.01 for all of them; with BMI as a fixed variable). Lymphocytes from acromegalic patients showed increased CD49d content (282 +/- 59 vs. 246 +/- 48 arbitrary units, respectively; P < 0.05). CONCLUSIONS: Taken together, the alterations described seem to contribute to constituting a state of higher propensity for the development of atherosclerotic cardiovascular disease, which adds to the presence of specific cardiomyopathy.


Assuntos
Acromegalia/complicações , Biomarcadores/sangue , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/etiologia , 1-Alquil-2-acetilglicerofosfocolina Esterase/sangue , Adulto , Idoso , Glicemia/metabolismo , Proteína C-Reativa/metabolismo , Antígenos CD18/sangue , Proteínas de Transferência de Ésteres de Colesterol , Endotelina-1/sangue , Feminino , Humanos , Integrina alfa4/sangue , Molécula 1 de Adesão Intercelular/sangue , Lipoproteínas/sangue , Masculino , Pessoa de Meia-Idade , Triglicerídeos/sangue , Molécula 1 de Adesão de Célula Vascular/metabolismo
16.
J Comput Sci ; 11: 102-111, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36776413

RESUMO

This work explores a method for classifying peaks appearing within a data-intensive time-series. We summarize a case study from a clinical trial aimed at reducing secondhand smoke exposure via the installation of air particle monitors in households. Proper orthogonal decomposition (POD) in conjunction with a k-means clustering algorithm assigns each data peak to one of two clusters. Aversive feedback from the monitors increased the proportion of short-duration, attenuated peaks from 38.8% to 96.6%. For each cluster, a distribution of parameters from a physics-based model of airborne particles is estimated. Peaks generated from these distributions are correctly identified by POD/clustering with >60% accuracy.

17.
Neurology ; 38(5): 736-9, 1988 May.
Artigo em Inglês | MEDLINE | ID: mdl-3362371

RESUMO

We studied the case records of 16 patients with eastern equine encephalitis (EEE) in Massachusetts from 1970 to 1984 and compared their presentations, courses, and outcomes with the data available from previous epidemics. In recent years, there has been a greater frequency of EEE in adults, whereas in the past it was considered a disease of children. Also, prognosis for a good functional recovery seems to be correlated with age over 40 years, a long prodromal course (5 to 7 days) of constitutional symptoms, and the absence of coma. Previous reports did not mention these significant correlations. We also stress the positive and negative diagnostic correlations, in order to distinguish between EEE and herpes simplex encephalitis.


Assuntos
Encefalomielite Equina/epidemiologia , Adolescente , Adulto , Encéfalo/microbiologia , Líquido Cefalorraquidiano/citologia , Criança , Eletroencefalografia , Encefalomielite Equina/complicações , Encefalomielite Equina/microbiologia , Encefalomielite Equina/fisiopatologia , Contagem de Eritrócitos , Humanos , Contagem de Leucócitos , Masculino , Massachusetts , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios X
18.
Immunol Lett ; 75(2): 137-41, 2001 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-11137138

RESUMO

VRCTC-310-Onco (crotoxin, a secretory phospholipase A2+cardiotoxin) is under development as an anti-neoplastic agent. Pro-inflammatory cytokines TNF-alpha and interleukin 1 alpha (IL-1alpha) and anti-inflammatory cytokine IL-1 receptor antagonist (IL-1ra) were measured with commercial ELISA kits in sera corresponding to 23 cycles with doses between 0.0025 and 0.023 microg/kg body weight, obtained during the phase I trial of VRCTC-310-Onco. Neither serum TNF-alpha nor IL-1alpha did change significantly after VRCTC-310-Onco. Basal IL-1ra was 794 +/- 97 pg/ml, by 3 h it was similar, 651 +/- 99 pg/ml and at 24 h p.i. it increased to 1197 +/- 122 pg/ml (P<0.001). The increase was dose-dependent. The addition of dexamethasone (required to reduce pain with the highest doses) inhibited IL-1alpha and enhanced the induction of IL-1ra by VRCTC-310-Onco. Summing up, in vivo, in humans, in the dose range tested, VRCTC-310-Onco induces IL-1ra, and does not consistently modify IL-1alpha or TNF-alpha serum levels.


Assuntos
Proteínas Cardiotóxicas de Elapídeos/farmacologia , Crotoxina/farmacologia , Interleucina-1/sangue , Fosfolipases A/farmacologia , Sialoglicoproteínas/sangue , Fator de Necrose Tumoral alfa/metabolismo , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacologia , Proteínas Cardiotóxicas de Elapídeos/administração & dosagem , Dexametasona/administração & dosagem , Feminino , Humanos , Mediadores da Inflamação/sangue , Proteína Antagonista do Receptor de Interleucina 1 , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Fosfolipases A/administração & dosagem , Fosfolipases A2
19.
IEEE Trans Neural Netw ; 14(3): 668-79, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-18238047

RESUMO

Bias and variance play an important role in understanding the fundamental issue of learning and generalization in neural network modeling. Several studies on bias and variance effects have been published in classification and regression related research of neural networks. However, little research has been done in this area for time-series modeling and forecasting. We consider modeling issues related to understanding error components given the common practices associated with neural-network time-series forecasting. We point out the key difference between classification and time-series problems in consideration of the bias-plus-variance decomposition. A Monte Carlo study on the role of bias and variance in neural networks time-series forecasting is conducted. We find that both input lag structure and hidden nodes are important in contributing to the overall forecasting performance. The results also suggest that overspecification of input nodes in neural network modeling does not impact the model bias, but has significant effect on the model variance. Methods such as neural ensembles that focus on reducing the model variance, therefore, can be valuable and effective in time-series forecasting modeling.

20.
Int Surg ; 85(3): 209-15, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11324997

RESUMO

The extent of lymph node dissection in stomach adenocarcinoma is currently under debate. Japanese data strongly support the therapeutic value of extended lymphadenectomy (D2 node dissection), whereas in Western countries several prospective trials have recently been completed with contrasting results. During the period May 1993 to May 1998, 164 patients with gastric cancer were observed: 136 patients, treated with a radical surgical procedure including lymph node dissection according to the guidelines of the Japanese Research Society for Gastric Cancer, were eligible for our analysis. Clinical, histopathological, and surgical factors were examined for their influence on long-term survival. Our results on morbidity and mortality rates are similar to Japanese series: we suggest that the experience and training of the surgeon and his personal attitude towards extensive lymph node dissection may, therefore, be a major factor influencing the morbidity associated with the procedure. The relatively high estimated 3-year survival rate (52%) suggests support for extended lymphadenectomy (D2 dissection) in gastric cancer as standard treatment.


Assuntos
Adenocarcinoma/cirurgia , Excisão de Linfonodo/métodos , Neoplasias Gástricas/cirurgia , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Idoso , Feminino , Humanos , Masculino , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologia , Taxa de Sobrevida
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