883 research outputs found
Dynanics of a vehicle-track coupling system at a rail joint
The dynamic behaviour at a rail joint is examined using a two-dimensional vehicle–track coupling model. The track system is described as a finite-length beam resting on a double-layer discrete viscous-elastic foundation. The vehicle is represented by a half car body and a single bogie. The influence of the number of layers considered, the number of elements between two sleepers, and the beam model is investigated. Parametric studies, both of the coupling model and the analytic formulae, are carried out in order to understand the influence of the main track and vehicle parameters on the P1 and P2 peak forces. Finally, the results in terms of P2 force from the proposed model are compared, not only with measured values but also with other simulated and analytical solutions. An excellent agreement between these values is foun
Using Chemically Enhanced Primary Treatment (CEPT) as a pretreatment option for anaerobic digestate from cattle manure digestion system
© 2017 by the authors. Anaerobic digestate from cattle manure fermentation may pose a threat to the environment. How to stabilize the digestate's characteristics so that they do not disturb the bio-system is a critical issue for digestate management. Chemically enhanced primary treatment (CEPT) was investigated as a pretreatment option for digestate treatment. The performance of CEPT for digestate management was carried out under rapid mixing (200 r/min) and slow stirring (40 r/min), respectively. The optimal dosage of ferric chloride (FeCl3) was 40 mg/L. The combination of FeCl3 and anionic polyacrylamide (APAM) had no obvious influence on TP removal, while COD removal efficiency was improved by 15.4%. The digestate pH and temperature remained stable for CEPT application and required no adjustment. The results indicate that CEPT was effective and feasible in enhancing the removal of COD and TP for digestate pretreatment by using FeCl3 and APAM
The perks of doing housework: Longitudinal associations with survival and underlying mechanisms
This is the final version. Available from BioMed Central via the DOI in this record. Data Availability.
The data that support the findings of this study are available from Mr. & Ms. Os Hong Kong cohort study (http://www.jococ.org/en/mros-msos.php), but restrictions apply to the availability of these data, which were used under license for the current study, and so the data are not publicly available. Data are, however, available from Prof. Timothy Kwok ([email protected]) upon reasonable request and with permission of the Jockey Club Centre for Osteoporosis Care and Control.BACKGROUND: Although the majority of existing literature has suggested positive effects of housework on older adults' health and survival rate, the underlying mechanisms of such effects remain unclear. To address potential mechanisms, the present study examined the association between older adults' housework engagement and days of survival across 14 years and tested three potential mediation pathways in this association. METHODS: Four thousand Hong Kong older adults (50% female; aged between 65 and 98 years) participated in a longitudinal study in which they reported initial housework engagement and health status across three domains (cognitive functioning, physical health, and mental health) at the baseline, and the numbers of days they survived over the subsequent 14-year period were recorded. Linear regression, Cox proportional hazard, and parallel mediation analyses were performed to examine the relationship between housework engagement and days survived, and the mediating effects of these three health factors. RESULTS: The results showed a positive association between housework engagement and days survived after controlling for demographic variables (age, sex, education, marital status, subjective social status, and living alone). Physical health and mental health, but not cognitive functioning, partially mediated the relationship between housework engagement and days survived. The findings suggest that doing housework may contribute to longer survival by improving older adults' physical and mental health. CONCLUSION: The current study confirms positive relations of housework with health and mortality among Hong Kong older adults. As the first study examining the relationships and mediation pathways between doing housework and survival in later life, the findings advance our understanding of the mechanisms underlying the positive association between housework and mortality and provide insights for future daily-life health-promotion interventions for older adults.National Institutes of HealthResearch Grants Counci
CD4 T lymphocyte autophagy is upregulated in the salivary glands of primary Sjögren’s syndrome patients and correlates with focus score and disease activity
Background: Primary Sjögren’s syndrome (pSS) is a common chronic autoimmune disease characterized by
lymphocytic infiltration of exocrine glands and peripheral lymphocyte perturbation. In the current study, we
aimed to investigate the possible pathogenic implication of autophagy in T lymphocytes in patients with pSS.
Methods: Thirty consecutive pSS patients were recruited together with 20 patients affected by sicca syndrome a
nd/or chronic sialoadenitis and 30 healthy controls. Disease activity and damage were evaluated according to SS
disease activity index, EULAR SS disease activity index, and SS disease damage index. T lymphocytes were analyzed
for the expression of autophagy-specific markers by biochemical, molecular, and histological assays in peripheral
blood and labial gland biopsies. Serum interleukin (IL)-23 and IL-21 levels were quantified by enzyme-linked
immunosorbent assay.
Results: Our study provides evidence for the first time that autophagy is upregulated in CD4+ T lymphocyte salivary
glands from pSS patients. Furthermore, a statistically significant correlation was detected between lymphocyte
autophagy levels, disease activity, and damage indexes. We also found a positive correlation between autophagy
enhancement and the increased salivary gland expression of IL-21 and IL-23, providing a further link between innate
and adaptive immune responses in pSS.
Conclusions: These findings suggest that CD4+ T lymphocyte autophagy could play a key role in pSS pathogenesis.
Additionally, our data highlight the potential exploitation of T cell autophagy as a biomarker of disease activity and
provide new ground to verify the therapeutic implications of autophagy as an innovative drug target in pSS
Effective theories of single field inflation when heavy fields matter
We compute the low energy effective field theory (EFT) expansion for
single-field inflationary models that descend from a parent theory containing
multiple other scalar fields. By assuming that all other degrees of freedom in
the parent theory are sufficiently massive relative to the inflaton, it is
possible to derive an EFT valid to arbitrary order in perturbations, provided
certain generalized adiabaticity conditions are respected. These conditions
permit a consistent low energy EFT description even when the inflaton deviates
off its adiabatic minimum along its slowly rolling trajectory. By generalizing
the formalism that identifies the adiabatic mode with the Goldstone boson of
this spontaneously broken time translational symmetry prior to the integration
of the heavy fields, we show that this invariance of the parent theory dictates
the entire non-perturbative structure of the descendent EFT. The couplings of
this theory can be written entirely in terms of the reduced speed of sound of
adiabatic perturbations. The resulting operator expansion is distinguishable
from that of other scenarios, such as standard single inflation or DBI
inflation. In particular, we re-derive how certain operators can become
transiently strongly coupled along the inflaton trajectory, consistent with
slow-roll and the validity of the EFT expansion, imprinting features in the
primordial power spectrum, and we deduce the relevant cubic operators that
imply distinct signatures in the primordial bispectrum which may soon be
constrained by observations.Comment: (v1) 25 pages, 1 figure; (v2) references added and typos corrected,
to appear in Journal of High Energy Physic
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
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
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