Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Wellbeing and arthritis incidence:The survey of health, ageing and retirement in Europe

BACKGROUND: A number of studies provide evidence for an association between psychosocial factors and risk of incident arthritis. Current evidence is largely limited to the examination of negative factors such as perceived stress, but positive factors such as subjective wellbeing may also play a role. PURPOSE: The purpose of the current study was to investigate whether people with higher subjective wellbeing have a lower risk of developing arthritis. METHODS: We used Cox proportional hazards regression to examine the prospective relationship between wellbeing (measured using the CASP-12) and incidence of arthritis over a 9-year period. The sample consisted of 13,594 participants aged ≥50 years from the Survey of Health, Ageing and Retirement in Europe. RESULTS: There was a significant association between greater wellbeing and reduced incident arthritis that was stronger at younger ages. In sex-adjusted analyses, for a standard deviation increase in CASP-12 score, the hazard ratios (95 % confidence intervals) for incident arthritis in people aged <65 and ≥65 years were 0.73 (0.69–0.77) and 0.80 (0.77–0.85), respectively. After further adjustment for other established risk factors, these associations were attenuated but remained significant in both age groups: the fully adjusted hazard ratios were 0.82 (0.77–0.87) and 0.88 (0.82–0.95), respectively. CONCLUSIONS: These results provide evidence for an association between greater wellbeing and reduced risk of incident arthritis and, more generally, support the theory that psychosocial factors are implicated in the aetiology of this disease. Future research needs to delineate the mechanisms underlying the association between wellbeing and arthritis risk. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s12160-015-9764-6) contains supplementary material, which is available to authorized users