1,031 research outputs found
Observational constraints on cosmic neutrinos and dark energy revisited
Using several cosmological observations, i.e. the cosmic microwave background
anisotropies (WMAP), the weak gravitational lensing (CFHTLS), the measurements
of baryon acoustic oscillations (SDSS+WiggleZ), the most recent observational
Hubble parameter data, the Union2.1 compilation of type Ia supernovae, and the
HST prior, we impose constraints on the sum of neutrino masses (\mnu), the
effective number of neutrino species (\neff) and dark energy equation of
state (), individually and collectively. We find that a tight upper limit on
\mnu can be extracted from the full data combination, if \neff and are
fixed. However this upper bound is severely weakened if \neff and are
allowed to vary. This result naturally raises questions on the robustness of
previous strict upper bounds on \mnu, ever reported in the literature. The
best-fit values from our most generalized constraint read
\mnu=0.556^{+0.231}_{-0.288}\rm eV, \neff=3.839\pm0.452, and
at 68% confidence level, which shows a firm lower limit on
total neutrino mass, favors an extra light degree of freedom, and supports the
cosmological constant model. The current weak lensing data are already helpful
in constraining cosmological model parameters for fixed . The dataset of
Hubble parameter gains numerous advantages over supernovae when ,
particularly its illuminating power in constraining \neff. As long as is
included as a free parameter, it is still the standardizable candles of type Ia
supernovae that play the most dominant role in the parameter constraints.Comment: 39 pages, 15 figures, 7 tables, accepted to JCA
PS-PVD thermal/environmental barrier coatings with novel microstructures
Plasma spray physical vapor deposition (PS-PVD) technology has attracted increasing attention due to it promising potential in processing advanced functional coatings such as thermal/environmental barrier coatings (TBCs) by flexibly tailoring the coating microstructure architecture in a broad range. In this work, yttria stabilized zirconia (YSZ) TBCs with a novel quasi-columnar structure was prepared by co-deposition of vapor phase and nano-clusters using PS-PVD and the associated deposition mechanism was discussed. The thermo-physical and mechanical properties, sintering resistance and thermal shock life of the coating were investigated. The thermal conductivity is in a range of 0.7~1.0 W/mk between 200 °C and 1200 °C and the average life is ~4000 cycles during thermal shock testing in which the coating surface was heated to 1200 °C within 20 s and held at the temperature for 5 min by gas flame. Noted that the quasi-columnar TBC revealed much better resistance to glassy CaO-MgO-Al2O3-SiO2 (CMAS) adsorption than those TBCs produced by air plasma spray (APS) and electron beam physical vapor deposition (EB-PVD) and some attempts were made to understand the related mechanisms.
Ytterbium silicate/mullite/Si environmental barrier coatings (EBCs) were sprayed onto SiC ceramic matrix composites (CMC) by PS-PVD. The dense ytterbium silicate coating deposited at 65 kw is mainly composed of ytterbium disilicate resulting from vapor-phase deposition, whereas the layered coating at 40 kw is mainly ytterbium monosilicate from liquid deposition
Synthesis of Esters of Ginsenoside Metabolite M1 and Their Cytotoxicity on MGC80-3 Cells
molecule
Association among dietary magnesium, serum magnesium, and diabetes: a crosssectional study in middle-aged and older adults
Background: A number of studies have reported the association between
magnesium (Mg) and diabetes. However, the various conclusions were
inconsistent and the data on the Chinese population was limited. The
objective of this study was to evaluate the association among dietary
Mg, serum Mg, and diabetes in Chinese adults. Methods: A
cross-sectional study that contained 2904 subjects was conducted.
Biochemical test results and dietary intakes of subjects were collected
for analysis. The adjusted odds ratios (ORs) and the corresponding 95 %
confidence intervals (95 % CIs) were used to determine the relationship
between Mg status and diabetes by logistic regression. Results: The
prevalence of diabetes of the investigated population was 10.1 %.
Dietary Mg intake was not significantly correlated with diabetes (P
> 0.05). The significant negative association between serum Mg and
diabetes existed, and the multivariate adjusted OR was 0.34 (95 % CI
0.24, 0.49) in model 3 for the highest quartile of serum Mg compared
with the lowest. The P values for trend were all less than 0.001 for
the relationship between serum Mg and diabetes. Dietary Mg intake and
serum Mg were not significantly correlated in the diabetes population
(P = 0.936). Conclusions: Dietary Mg was not significantly correlated
with diabetes, while serum Mg was inversely correlated with diabetes in
the Chinese population. Meanwhile, dietary Mg intake and serum Mg were
not significantly correlated in the diabetes population
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