9,480 research outputs found
Stress across the life course and depression in a rapidly developing population: The Guangzhou Biobank Cohort Study
postprin
Study of psi(2S) decays to X J/psi
Using J/psi -> mu^+ mu^- decays from a sample of approximately 4 million
psi(2S) events collected with the BESI detector, the branching fractions of
psi(2S) -> eta J/psi, pi^0 pi^0 J/psi, and anything J/psi normalized to that of
psi(2S) -> pi^+ pi^- J/psi are measured. The results are B(psi(2S) -> eta
J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 0.098 \pm 0.005 \pm 0.010, B(psi(2S) ->
pi^0 pi^0 J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 0.570 \pm 0.009 \pm 0.026, and
B(psi(2S) -> anything J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 1.867 \pm 0.026
\pm 0.055.Comment: 13 pages, 8 figure
First observation of psi(2S)-->K_S K_L
The decay psi(2S)-->K_S K_L is observed for the first time using psi(2S) data
collected with the Beijing Spectrometer (BESII) at the Beijing Electron
Positron Collider (BEPC); the branching ratio is determined to be
B(psi(2S)-->K_S K_L) = (5.24\pm 0.47 \pm 0.48)\times 10^{-5}. Compared with
J/psi-->K_S K_L, the psi(2S) branching ratio is enhanced relative to the
prediction of the perturbative QCD ``12%'' rule. The result, together with the
branching ratios of psi(2S) decays to other pseudoscalar meson pairs
(\pi^+\pi^- and K^+K^-), is used to investigate the relative phase between the
three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.Comment: 5 pages, 4 figures, 2 tables, submitted to Phys. Rev. Let
Detection of mild to moderate influenza A/H7N9 infection by China's national sentinel surveillance system for influenza-like illness: case series
published_or_final_versio
Role of cellular senescence and NOX4-mediated oxidative stress in systemic sclerosis pathogenesis.
Systemic sclerosis (SSc) is a systemic autoimmune disease characterized by progressive fibrosis of skin and numerous internal organs and a severe fibroproliferative vasculopathy resulting frequently in severe disability and high mortality. Although the etiology of SSc is unknown and the detailed mechanisms responsible for the fibrotic process have not been fully elucidated, one important observation from a large US population study was the demonstration of a late onset of SSc with a peak incidence between 45 and 54 years of age in African-American females and between 65 and 74 years of age in white females. Although it is not appropriate to consider SSc as a disease of aging, the possibility that senescence changes in the cellular elements involved in its pathogenesis may play a role has not been thoroughly examined. The process of cellular senescence is extremely complex, and the mechanisms, molecular events, and signaling pathways involved have not been fully elucidated; however, there is strong evidence to support the concept that oxidative stress caused by the excessive generation of reactive oxygen species may be one important mechanism involved. On the other hand, numerous studies have implicated oxidative stress in SSc pathogenesis, thus, suggesting a plausible mechanism in which excessive oxidative stress induces cellular senescence and that the molecular events associated with this complex process play an important role in the fibrotic and fibroproliferative vasculopathy characteristic of SSc. Here, recent studies examining the role of cellular senescence and of oxidative stress in SSc pathogenesis will be reviewed
Resonances in and
A partial wave analysis is presented of and
from a sample of 58M events in the BES II detector. The
is observed clearly in both sets of data, and parameters of the
Flatt\' e formula are determined accurately: (stat)
(syst) MeV/c, MeV/c, . The data also exhibit a strong peak
centred at MeV/c. It may be fitted with and a
dominant signal made from interfering with a smaller
component. There is evidence that the signal is
resonant, from interference with . There is also a state in with MeV/c and
MeV/c; spin 0 is preferred over spin 2. This state, , is
distinct from . The data contain a strong peak due to
. A shoulder on its upper side may be fitted by interference
between and .Comment: 17 pages, 6 figures, 1 table. Submitted to Phys. Lett.
Measurement of the Branching Fraction of J/psi --> pi+ pi- pi0
Using 58 million J/psi and 14 million psi' decays obtained by the BESII
experiment, the branching fraction of J/psi --> pi+ pi- pi0 is determined. The
result is (2.10+/-0.12)X10^{-2}, which is significantly higher than previous
measurements.Comment: 9 pages, 8 figures, RevTex
Search for K_S K_L in psi'' decays
K_S K_L from psi'' decays is searched for using the psi'' data collected by
BESII at BEPC, the upper limit of the branching fraction is determined to be
B(psi''--> K_S K_L) < 2.1\times 10^{-4} at 90% C. L. The measurement is
compared with the prediction of the S- and D-wave mixing model of the
charmonia, based on the measurements of the branching fractions of J/psi-->K_S
K_L and psi'-->K_S K_L.Comment: 5 pages, 1 figur
First Measurements of eta_c Decaying into K^+K^-2(pi^+pi^-) and 3(pi^+pi^-)
The decays of eta_c to K^+K^-2(pi^+pi^-) and 3(pi^+pi^-) are observed for the
first time using a sample of 5.8X10^7 J/\psi events collected by the BESII
detector. The product branching fractions are determined to be B(J/\psi-->gamma
eta_c)*B(eta_c-->K^+K^-pi^+pi^-pi^+pi^-)=(1.21+-0.32+-
0.23)X10^{-4}, and (J/\psi-->gamma eta_c)*
B(eta_c-->pi^+pi^-pi^+pi^-pi^+pi^-)= (2.59+-0.32+-0.48)X10^{-4}. The upper
limit for eta_c-->phi pi^+pi^-pi^+pi^- is also obtained as B(J/\psi-->gamma
eta_c)*B(eta_c--> phi pi^+pi^-pi^+pi^-)< 6.03 X10^{-5} at the 90% confidence
level.Comment: 11 pages, 4 figure
Electron irradiation induced nanocrystal formation in Cu-borosilicate glass
Nanoscale writing of Cu nanoparticles in glasses is introduced using focused electron irradiation by transmission electron microscopy. Two types of copper borosilicate glasses, one with high and another with low Cu loading, have been tested at energies of 200–300 keV, and formation of Cu nanoparticles in a variety of shapes and sizes using different irradiation conditions is achieved. Electron energy loss spectroscopy analysis, combined with high-resolution transmission electron microscopy imaging, confirmed the irradiation-induced precipitated nanoparticles as metallic, while furnace annealing of the glass triggered dendrite-shaped particles of copper oxide. Unusual patterns of nanoparticle rings and chains under focused electron beam irradiation are also presented. Conclusively, electron beam patterning of Cu-loaded glasses is a promising alternative route to well-established femtosecond laser photoreduction of Cu ions in glass
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