24 research outputs found
Neutrino masses in R-parity violating supersymmetric models
We study neutrino masses and mixing in R-parity violating supersymmetric
models with generic soft supersymmetry breaking terms. Neutrinos acquire masses
from various sources: Tree level neutrino--neutralino mixing and loop effects
proportional to bilinear and/or trilinear R-parity violating parameters. Each
of these contributions is controlled by different parameters and have different
suppression or enhancement factors which we identified. Within an Abelian
horizontal symmetry framework these factors are related and specific
predictions can be made. We found that the main contributions to the neutrino
masses are from the tree level and the bilinear loops and that the observed
neutrino data can be accommodated once mild fine-tuning is allowed.Comment: 18 pages; minor typos corrected. To be published in Physical Review
One particle spectral weight of the three dimensional single band Hubbard model
Dynamic properties of the three-dimensional single-band Hubbard model are
studied using Quantum Monte Carlo combined with the maximum entropy technique.
At half-filling, there is a clear gap in the density of states and well-defined
quasiparticle peaks at the top (bottom) of the lower (upper) Hubbard band. We
find an antiferromagnetically induced weight above the naive Fermi momentum.
Upon hole doping, the chemical potential moves to the top of the lower band
where a robust peak is observed. Results are compared with spin-density-wave
(SDW) mean-field and self consistent Born approximation results, and also with
the infinite dimensional Hubbard model, and experimental photoemission (PES)
for three dimensional transition-metal oxides.Comment: 11 pages, REVTeX, 16 figures included using psfig.sty. Ref.30
correcte
Elephants respond to resource trade-offs in an aseasonal system through daily and annual variability in resource selection
Pattern of arterial involvement of the head, neck, and eyes in giant cell arteritis: three case reports.
The dependence of complex alloyed steel properties on quenching and tempering conditions
Spikes with short inter-spike intervals in frog retinal ganglion cells are more correlated with their adjacent neurons’ activities
Marital status and suicide in the National Longitudinal Mortality Study
OBJECTIVES—The purpose of the study was to examine the effect of marital status on the risk of suicide, using a large nationally representative sample. A related objective was to investigate the association between marital status and suicide by sex.
METHODS—Cox proportional hazards regression models were applied to data from the National Longitudinal Mortality Study, based on the 1979-1989 follow up. In estimating the effect of marital status, adjustments were made for age, sex, race, education, family income, and region of residence.
RESULTS—For the entire sample, higher risks of suicide were found in divorced than in married persons. Divorced and separated persons were over twice as likely to commit suicide as married persons (RR=2.08, 95% confidence intervals (95% CI) 1.58, 2.72). Being single or widowed had no significant effect on suicide risk. When data were stratified by sex, it was observed that the risk of suicide among divorced men was over twice that of married men (RR=2.38, CI 1.77, 3.20). Among women, however, there were no statistically significant differentials in the risk of suicide by marital status categories.
CONCLUSIONS—Marital status, especially divorce, has strong net effect on mortality from suicide, but only among men. The study showed that in epidemiological research on suicide, more accurate results would be obtained if samples are stratified on the basis of key demographic or social characteristics. The study further observed that failure to control for relevant socioeconomic variables or combining men and women in the same models could produce misleading results.


Keywords: suicide; marital status; socioeconomic status; effect modificatio