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1.
Phys Rev Lett ; 127(17): 171801, 2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34739288

RESUMO

Using a dataset of 6.32 fb^{-1} of e^{+}e^{-} annihilation data collected with the BESIII detector at center-of-mass energies between 4178 and 4226 MeV, we have measured the absolute branching fraction of the leptonic decay D_{s}^{+}→τ^{+}ν_{τ} via τ^{+}→e^{+}ν_{e}ν[over ¯]_{τ}, and find B_{D_{s}^{+}→τ^{+}ν_{τ}}=(5.27±0.10±0.12)×10^{-2}, where the first uncertainty is statistical and the second is systematic. The precision is improved by a factor of 2 compared to the previous best measurement. Combining with f_{D_{s}^{+}} from lattice quantum chromodynamics calculations or the |V_{cs}| from the CKMfitter group, we extract |V_{cs}|=0.978±0.009±0.012 and f_{D_{s}^{+}}=(251.1±2.4±3.0) MeV, respectively. Combining our result with the world averages of B_{D_{s}^{+}→τ^{+}ν_{τ}} and B_{D_{s}^{+}→µ^{+}ν_{µ}}, we obtain the ratio of the branching fractions B_{D_{s}^{+}→τ^{+}ν_{τ}}/B_{D_{s}^{+}→µ^{+}ν_{µ}}=9.72±0.37, which is consistent with the standard model prediction of lepton flavor universality.

2.
Phys Rev Lett ; 127(12): 121802, 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34597097

RESUMO

The absolute branching fraction of Λ→pµ^{-}ν[over ¯]_{µ} is reported for the first time based on an e^{+}e^{-} annihilation sample of 10×10^{9} J/ψ events collected with the BESIII detector at sqrt[s]=3.097 GeV. The branching fraction is determined to be B(Λ→pµ^{-}ν[over ¯]_{µ})=[1.48±0.21(stat)±0.08(syst)]×10^{-4}, which is improved by about 30% in precision over the previous indirect measurements. Combining this result with the world average of B(Λ→pe^{-}ν[over ¯]_{e}), we obtain the ratio {[Γ(Λ→pµ^{-}ν[over ¯]_{µ})]/[Γ(Λ→pe^{-}ν[over ¯]_{e})]} to be 0.178±0.028, which agrees with the standard model prediction assuming lepton flavor universality. The asymmetry of the branching fractions of Λ→pµ^{-}ν[over ¯]_{µ} and Λ[over ¯]→p[over ¯]µ^{+}ν_{µ} is also determined, and no evidence for CP violation is found.

3.
Phys Rev Lett ; 127(13): 131801, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34623854

RESUMO

Using 2.93 fb^{-1} of e^{+}e^{-} collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} semileptonic decay is presented. The statistical significance of the decay D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is greater than 10σ. The branching fraction of D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is measured to be (1.09±0.13_{-0.16}^{+0.09}±0.12)×10^{-3}. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K_{1}(1270)^{-}→K^{-}π^{+}π^{-}. The fraction of longitudinal polarization in D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is determined for the first time to be 0.50±0.19_{stat}±0.08_{syst}.

5.
Phys Rev Lett ; 127(8): 082002, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34477419

RESUMO

We report a measurement of the observed cross sections of e^{+}e^{-}→J/ψX based on 3.21 fb^{-1} of data accumulated at energies from 3.645 to 3.891 GeV with the BESIII detector operated at the BEPCII collider. In analysis of the cross sections, we measured the decay branching fractions of B(ψ(3686)→J/ψX)=(64.4±0.6±1.6)% and B(ψ(3770)→J/ψX)=(0.5±0.2±0.1)% for the first time. The energy-dependent line shape of these cross sections cannot be well described by two Breit-Wigner (BW) amplitudes of the expected decays ψ(3686)→J/ψX and ψ(3770)→J/ψX. Instead, it can be better described with one more BW amplitude of the decay R(3760)→J/ψX. Under this assumption, we extracted the R(3760) mass M_{R(3760)}=3766.2±3.8±0.4 MeV/c^{2} , total width Γ_{R(3760)}^{tot}=22.2±5.9±1.4 MeV, and product of leptonic width and decay branching fraction Γ_{R(3760)}^{ee}B[R(3760)→J/ψX]=(79.4±85.5±11.7) eV. The significance of the R(3760) is 5.3σ. The first uncertainties of these measured quantities are from fits to the cross sections and second systematic.

6.
Artigo em Chinês | MEDLINE | ID: mdl-34488265

RESUMO

Objective: To analyze the application of Chronic Obstructive Pulmonary Disease (COPD) Screening Questionnaire and pulmonary function test in dust-exposed migrant workers. Methods: In May 2019, 149 cases of dust exposed migrant workers were selected as the research subjects through the free clinic in the countryside. COPD Screening Questionnaire and lung function test were carried out to analyze the high-risk groups and the influencing factors of positive pulmonary function test results. Results: Among 149 cases of dust-exposed migrant workers, 107 (71.8%) were positive for questionnaire screening, 73 (49.0%) were positive for pulmonary function test, 75 (50.3%) were diagnosed with coal worker's pneumoconiosis, and 101 (67.8%) were diagnosed with lung function injury. The positive rate of pulmonary function of migrant workers with positive questionnaire screening results was significantly higher than that of those with negative results (P<0.05) . The results of multivariate analysis showed that compared with non-pneumoconiosis, the risk of positive pulmonary function test results was higher in dust-exposed migrant workers with stage Ⅲ pneumoconiosis (OR=16.462, 95%CI: 3.390-79.946; P<0.01) . Compared with non-smoking, the risks of positive pulmonary function test results of dust-exposed migrant workers with smoking index of 11-20 package years and >20 package years were higher (OR=19.814, 95%CI: 3.854-101.883; OR=9.733, 95%CI: 2.310-41.008; P<0.01) . Conclusion: The risk of COPD in dust-exposed migrant workers is high, so we should strengthen the early examination of the high pneumoconiosis stage and smoking population. The screening questionnaire can better screen out the high-risk groups of COPD, and it can be used as a basic screening tool.


Assuntos
Minas de Carvão , Exposição Ocupacional , Pneumoconiose , Doença Pulmonar Obstrutiva Crônica , Migrantes , Poeira , Humanos , Pneumoconiose/diagnóstico , Pneumoconiose/epidemiologia , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Testes de Função Respiratória , Inquéritos e Questionários
7.
Artigo em Inglês | MEDLINE | ID: mdl-34412929

RESUMO

Occult cervical lymph node metastasis is a significant prognostic factor in patients with early-stage (cT1/2N0) oral squamous cell carcinoma (OSCC). The aim of this study was to investigate the potential value of the tumor-stroma ratio (TSR) as a histological predictor of occult cervical metastasis and survival in early-stage OSCC. This retrospective study included 151 patients who underwent excision of the primary lesion and elective neck dissection from 2013 to 2017. The clinicopathological features of the tumor, risk factors associated with occult neck metastasis, and prognostic factors for overall survival (OS) and disease-free survival (DFS) were studied. A significant correlation of TSR (P = 0.009) was found with occult neck metastasis in the multivariate logistic regression model. Multivariate Cox proportional hazards regression analysis showed that the TSR (P = 0.002) and perineural invasion (P = 0.011) were associated with OS. Occult neck metastasis (P = 0.032) was associated with DFS. These findings indicate that assessment of the TSR might be useful in prognostication for early-stage OSCC patients. Moreover, the TSR is effective in allowing an accurate evaluation of the risk of occult neck metastasis, and this may be easily applicable in the routine pathological diagnosis and clinical decision-making for elective neck dissection.

8.
J Breath Res ; 15(4)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34343985

RESUMO

Respiratory viral infections are considered a major public health threat, and breath metabolomics can provide new ways to detect and understand how specific viruses affect the human pulmonary system. In this pilot study, we characterized the metabolic composition of human breath for an early diagnosis and differentiation of influenza viral infection, as well as other types of upper respiratory viral infections. We first studied the non-specific effects of planned seasonal influenza vaccines on breath metabolites in healthy subjects after receiving the immunization. We then investigated changes in breath content from hospitalized patients with flu-like symptoms and confirmed upper respiratory viral infection. The exhaled breath was sampled using a custom-made breath condenser, and exhaled breath condensate (EBC) samples were analysed using liquid chromatography coupled to quadruplole-time-of-flight mass spectrometer (LC-qTOF). All metabolomic data was analysed using both targeted and untargeted approaches to detect specific known biomarkers from inflammatory and oxidative stress biomarkers, as well as new molecules associated with specific infections. We were able to find clear differences between breath samples collected before and after flu vaccine administration, together with potential biomarkers that are related to inflammatory processes and oxidative stress. Moreover, we were also able to discriminate samples from patients with flu-related symptoms that were diagnosed with confirmatory respiratory viral panels (RVPs). RVP positive and negative differences were identified, as well as differences between specific viruses defined. These results provide very promising information for the further study of the effect of influenza A and other viruses in human systems by using a simple and non-invasive specimen like breath.

10.
Science ; 373(6553): 425-430, 2021 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-34261813

RESUMO

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 1036 ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

11.
Phys Rev Lett ; 126(24): 241103, 2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34213924

RESUMO

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25 TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160 TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

12.
Nature ; 594(7861): 33-36, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34002091

RESUMO

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 1015 electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays1. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

13.
Phys Rev Lett ; 126(9): 092002, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33750166

RESUMO

We present an analysis of the process ψ(3686)→Ω^{-}Ω[over ¯]^{+} (Ω^{-}→K^{-}Λ, Ω[over ¯]^{+}→K^{+}Λ[over ¯], Λ→pπ^{-}, Λ[over ¯]→p[over ¯]π^{+}) based on a dataset of 448×10^{6} ψ(3686) decays collected with the BESIII detector at the BEPCII electron-positron collider. The helicity amplitudes for the process ψ(3686)→Ω^{-}Ω[over ¯]^{+} and the decay parameters of the subsequent decay Ω^{-}→K^{-}Λ (Ω[over ¯]^{+}→K^{+}Λ[over ¯]) are measured for the first time by a fit to the angular distribution of the complete decay chain, and the spin of the Ω^{-} is determined to be 3/2 for the first time since its discovery more than 50 years ago.

14.
Phys Rev Lett ; 126(10): 102001, 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33784133

RESUMO

We report a study of the processes of e^{+}e^{-}→K^{+}D_{s}^{-}D^{*0} and K^{+}D_{s}^{*-}D^{0} based on e^{+}e^{-} annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb^{-1}. An excess of events over the known contributions of the conventional charmed mesons is observed near the D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0} mass thresholds in the K^{+} recoil-mass spectrum for events collected at sqrt[s]=4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5_{-2.6}^{+1.8}±2.1) MeV/c^{2} and (12.8_{-4.4}^{+5.3}±3.0) MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0}. However, the properties of the excess need further exploration with more statistics.

15.
Zhonghua Xue Ye Xue Za Zhi ; 42(1): 33-38, 2021 Jan 14.
Artigo em Chinês | MEDLINE | ID: mdl-33677866

RESUMO

Objectives: To cross-sectionally analyze the clinical characteristics of primary antiphospholipid syndrome (PAPS) patients with thrombocytopenia, risk factors associated with thrombocytopenia, and risk of symptom recurrence in these patients. Methods: The inpatients with PAPS were retrospectively analyzed in Peking Union Medical College Hospital from 2009 to 2019. Using the collected clinical and laboratory data, the clinical characteristics and risk of symptom recurrence in the PAPS patients with thrombocytopenia were compared with those in the PAPS patients with normal platelet counts. Univariate and multivariate logistic regression analyses were performed to screen the risk factors for thrombocytopenia. Results: In this study, 127 patients with PAPS were enrolled, of which 36 (28.3% ) had thrombocytopenia, with a median age of 38 years, and 63.9% were female. In the thrombocytopenia group, the average platelet count was (58.9±27.0) ×10(9)/L, and the prevalence of thrombosis and morbid pregnancy was not significantly different from that in the normal platelet group. However, the thrombocytopenia group had higher incidence rate of autoimmune hemolytic anemia (19.4% vs 3.3% ) , livedo reticularis (16.7% vs 3.3% ) , chronic kidney disease (25% vs 8.8% ) and antiphospholipid antibodies triple positiveness (61.1% vs 37.4% ) , lower complement levels (C3 of 0.87 g/L vs 1.07 g/L, C4 of 0.12 g/L vs 0.18 g/L, P<0.05) , and higher adjusted Global APS Score (median score of 13 vs 9, P=0.037) than the normal platelet group. In multivariate logistic regression analysis, hypocomplementemia (OR value 5.032, 95% CI 3.118-22.095) is an independent risk factor for thrombocytopenia. Conclusions: In patients with PAPS, thrombocytopenia is mostly mild to moderate. Hypocomplementemia may be the independent risk factor for thrombocytopenia in PAPS patients. The PAPS patients with thrombocytopenia may have a higher risk of symptom recurrence.


Assuntos
Síndrome Antifosfolipídica , Trombocitopenia , Adulto , Anticorpos Antifosfolipídeos , Síndrome Antifosfolipídica/complicações , Feminino , Humanos , Masculino , Estudos Retrospectivos , Fatores de Risco , Trombocitopenia/epidemiologia
18.
Phytopathology ; : PHYTO10200472R, 2021 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33616417

RESUMO

Phytophthora ramorum is an invasive, broad host range pathogen that causes ramorum blight and sudden oak death in forest landscapes of western North America. In commercial nurseries, asymptomatic infections of nursery stock by P. ramorum and other Phytophthora species create unacceptable risk and complicate inspection and certification programs designed to prevent introduction and spread of these pathogens. In this study, we continue development of a volatile organic compound (VOC)-based test for detecting asymptomatic infections of P. ramorum in Rhododendron sp. We confirmed detection of P. ramorum from volatiles collected from asymptomatic root-inoculated Rhododendron plants in a nursery setting, finding that the VOC profile of infected plants is detectably different from that of healthy plants, when measured from both ambient VOC emissions and VOCs extracted from leaf material. Predicting infection status was successful from ambient volatiles, which had a mean area under the curve (AUC) value of 0.71 ± 0.17, derived from corresponding receiver operating characteristic curves from an extreme gradient boosting discriminant analysis. This finding compares with that of extracted leaf volatiles, which resulted in a lower AUC value of 0.51 ± 0.21. In a growth chamber, we contrasted volatile profiles of asymptomatic Rhododendron plants having roots infected with one of three pathogens: P. ramorum, P. cactorum, and Rhizoctonia solani. Each pathogen induced unique and measurable changes, but generally the infections reduced volatile emissions until 17 weeks after inoculation, when emissions trended upward relative to those of mock-inoculated controls. Forty-five compounds had significant differences compared with mock-inoculated controls in at least one host-pathogen combination.

19.
Zhonghua Xin Xue Guan Bing Za Zhi ; 49(1): 54-59, 2021 Jan 11.
Artigo em Chinês | MEDLINE | ID: mdl-33429487

RESUMO

Objective: To explore the association between healthy lifestyle and risk of rehospitalization in male or female patients with chronic heart failure (CHF). Methods: Discharged patients with CHF of Henan Provincial People's Hospital Collaboration Hospital were recruited in our study from January 1,2017 to December 31, 2018. The basic information of patients were collected through the electronic medical record system,the questionnaires were used to collect the related influencing factors. Healthy lifestyle includes 4 items, namely non-smoking, moderate exercise, healthy body mass index (BMI) and reasonable diet.Multivariate logistic regression was used to analyze the association between healthy lifestyle and the risk of rehospitalization of CHF patients of different genders. Results: A total of 2 697 patients with CHF were enrolled in this study, including 1 308 male patients(621 rehospitalizations,687 controls)and 1 389 female patients(684 rehospitalizations,705 controls).Among male patients, there was no significant difference in age, residence, marital status, education level, average monthly income, and medical insurance between the rehospitalization group and the control group (all P>0.05). Among female patients, there was no significant difference in age, residence, marital status, education level, average monthly income, and medical insurance between the rehospitalization group and the control group (all P>0.05). Whether in male or female patients with CHF, we found that patients with 4 healthy lifestyles were associated with reduced risk of rehospitalization: male patients OR=0.34, 95%CI 0.11-0.99, P=0.002,female patients OR=0.27, 95%CI 0.13-0.79, P=0.012. A combination of non-smoking and any other 2 healthy lifestyles was associated with reduced risk of rehospitalization: male patients with no smoking, moderate exercise, healthy BMI, OR=0.32, 95%CI 0.11-0.99, P=0.043; female patients OR=0.28, 95%CI 0.12-0.93, P=0.032;male patients with no smoking, moderate exercise, reasonable diet OR=0.42, 95%CI 0.24-0.98, P=0.044,female patients OR=0.40, 95%CI 0.12-0.94, P=0.031;male patients with no smoking, healthy BMI, reasonable diet OR=0.31, 95%CI 0.21-0.92, P=0.039,female patients OR=0.27,95%CI 0.11-0.87, P=0.014. In female patients with CHF, the combination of non-smoking and moderate sports was associated with reduced risk of hospitalization (OR=0.23, 95%CI 0.19-0.97, P=0.038), while no similar results were seen in male patients (OR=0.65, 95%CI 0.33-1.84, P=0.315). Conclusion: Healthy lifestyle is associated with reduced risk of rehospitalization in patients with CHF, and the related healthy lifestyle and its combination may differ between male and female patients.

20.
Nat Commun ; 12(1): 457, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33469031

RESUMO

Complex-valued neural networks have many advantages over their real-valued counterparts. Conventional digital electronic computing platforms are incapable of executing truly complex-valued representations and operations. In contrast, optical computing platforms that encode information in both phase and magnitude can execute complex arithmetic by optical interference, offering significantly enhanced computational speed and energy efficiency. However, to date, most demonstrations of optical neural networks still only utilize conventional real-valued frameworks that are designed for digital computers, forfeiting many of the advantages of optical computing such as efficient complex-valued operations. In this article, we highlight an optical neural chip (ONC) that implements truly complex-valued neural networks. We benchmark the performance of our complex-valued ONC in four settings: simple Boolean tasks, species classification of an Iris dataset, classifying nonlinear datasets (Circle and Spiral), and handwriting recognition. Strong learning capabilities (i.e., high accuracy, fast convergence and the capability to construct nonlinear decision boundaries) are achieved by our complex-valued ONC compared to its real-valued counterpart.

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