Measurements of charged current lepton universality and |Vus| using tau lepton decays to e- ν(e) ν(τ), μ- ν(μ) ν(τ), π- ν(τ), and K- ν(τ)

Using 467  fb(-1) of e+e- annihilation data collected with the BABAR detector, we measure (B(τ- → μ- ν(μ) ν(τ)))/(B(τ- → e- ν(e) ν(τ))) =(0.9796±0.0016±0.0036), (B(τ- → π- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.5945±0.0014±0.0061), and (B(τ- → K- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.03882±0.00032±0.00057), where the uncertainties are statistical and systematic, respectively. From these precision τ measurements, we test the standard model assumption of μ-e and τ-μ charge current lepton universality and provide determinations of |Vus| experimentally independent of the decay of a kaon.

Differential risk of employment in more physically demanding jobs among a recent cohort of immigrants to Canada

OBJECTIVE

To examine the proportion of a recent cohort of immigrants to Canada who were working in jobs that were more physically demanding than those in which they worked before migration to Canada.

DESIGN

Longitudinal cohort of immigrants to Canada with occupational position measured before and 2 and 4 years after arrival in Canada.

SUBJECTS

Respondents to Statistics Canada's Longitudinal Survey of Immigrants to Canada (LSIC). The LSIC surveyed a representative sample of immigrants, aged 15 and older, who arrived in Canada between November 2000 and December 2001. For the purpose of this study, the sample was restricted to respondents who had worked before immigrating and were working when re-interviewed 2 (n = 4331) or 4 (n = 4238) years after arrival in Canada.

MAIN OUTCOME

Employment in an occupation with higher physical demands than that employed in before arrival in Canada.

RESULTS

Respondents with less proficiency at speaking English and family class or refugee applicants were the most likely to be employed in occupations with higher physical demands both 2 and 4 years after arrival in Canada.

CONCLUSIONS

Employment in a more physically demanding occupation may pose particular risks of workplace injury. In this sample of immigrants to Canada, respondents with poorer English skills and refugees (factors that may increase this risk) were more likely to be employed in more physically demanding occupations. Greater attention to the prevention of workplace injuries among particular groups of new immigrants to Canada is required.

Review of chromium (VI) apoptosis, cell-cycle-arrest, and carcinogenesis

Hexavalent chromium combines with glutathione in chloride intracellular channel carrier to form tetravalent and pentavalent chromium in plasma and organelle membranes. It also combines with NADH/NADPH to form pentavalent chromium in mitochondria. Tetravalent- and pentavalent- chromium (directly and indirectly) mediated DNA double strand breaks activate DNA damage signaling sensors: DNA-dependent-protein-kinase signals p53-dependent intrinsic mitochondrial apoptosis, and ataxia-telangiectasia-mutated and ataxia-telangiectasia-Rad3-related signal cell-arrest for DNA repair. Tetravalent chromium may be the most potent species since it causes DNA breaks and somatic recombination, but not apoptosis. Upon further failure of apoptosis and senescence/DNA-repair, damaged cells may become immortal with loss-of-heterozygosity and genetic plasticity.