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

Neuropeptidergic Regulation of Food Intake in the Neonatal Chick: A Review

Immediately after hatching, neonatal chicks can find their food and control food intake, but the mechanisms for feeding are not completely understood. Food intake regulation in the brain involves neuropeptides. While some neuropeptides have effects similar to that observed in mammals, others have an opposite effect. Since the neonatal chick is precocial, the ability to obtain food is very important. However, the orexigenic factors are limited to neuropeptide Y, opioid, prolactin releasing peptide and gonadotropin-inhibitory hormone. The effects of anorexigenic peptides were well conserved in the neonatal chick. The higher food intake observed in broiler chicks can be explained by the lower expression of anorexigenic neuropeptides rather than the higher expression of orexigenic neuropeptides