Ejaculate allocation by male sand martins, Riparia riparia

Males of many species allocate sperm to ejaculates strategically in response to variation in the risk and intensity of sperm competition. The notable exception is passerine birds, in which evidence for strategic allocation is absent. Here we report the results of a study testing for strategic ejaculate allocation in a passerine bird, the sand martin (Riparia riparia). Natural ejaculates were collected from males copulating with a model female. Ejaculates transferred in the presence of a rival male contained significantly more sperm than ejaculates transferred in the absence of a rival male. There was no evidence that this difference was due to the confounding effects of the year of ejaculate collection, the identity of the model female, the colony, the stage of season or the period of the day in which ejaculates were collected. A more detailed examination of the ejaculate patterns of individual males, achieved by the DNA profiling of ejaculates, provided additional evidence for strategic allocation of sperm

Magna Carta, the Rule of Law and the Limits on Government

This paper surveys the legal tradition that links Magna Carta with the modern concepts of the rule of law and the limits on government. It documents that the original understanding of the rule of law included substantive commitments to individual freedom and limited government. Then, it attempts at explaining how and why such commitments were lost to a formalist interpretation of the rule of law from 1848 to 1939. The paper concludes by arguing how a revival of the substantive commitments of the rule of law is central in a project of reshaping modern states

Search for heavy resonances decaying into a W or Z boson and a Higgs boson in final states with leptons and b-jets in 36 fb(-1) of root s=13 TeV pp collisions with the ATLAS detector

A search is conducted for new resonances decaying into a W or Z boson and a 125 GeV Higgs boson in the νν¯¯¯bb¯¯, ℓ±νbb¯¯, and ℓ+ℓ−bb¯¯ final states, where ℓ± = e± or μ±, in pp collisions at s√=13 TeV. The data used correspond to a total integrated luminosity of 36.1 fb−1 collected with the ATLAS detector at the Large Hadron Collider during the 2015 and 2016 data-taking periods. The search is conducted by examining the reconstructed invariant or transverse mass distributions of W h and Zh candidates for evidence of a localised excess in the mass range of 220 GeV up to 5 TeV. No significant excess is observed and the results are interpreted in terms of constraints on the production cross-section times branching fraction of heavy W ′ and Z′ resonances in heavy-vector-triplet models and the CP-odd scalar boson A in two-Higgs-doublet models. Upper limits are placed at the 95% confidence level and range between 9.0 × 10−4 pb and 7.3 × 10−1 pb depending on the model and mass of the resonance

The role of peripheral T-cell deletion in transplantation tolerance.

The apoptotic deletion of thymocytes that express self-reactive antigen receptors is the basis of central (thymic) self-tolerance. However, it is clear that some autoreactive T cells escape deletion in the thymus and exist as mature lymphocytes in the periphery. Therefore, peripheral mechanisms of tolerance are also crucial, and failure of these peripheral mechanisms leads to autoimmunity. Clonal deletion, clonal anergy and immunoregulation and/or suppression have been suggested as mechanisms by which 'inappropriate' T-lymphocyte responses may be controlled in the periphery. Peripheral clonal deletion, which involves the apoptotic elimination of lymphocytes, is critical for T-cell homeostasis during normal immune responses, and is recognized as an important process by which self-tolerance is maintained. Transplantation of foreign tissue into an adult host represents a special case of 'inappropriate' T-cell reactivity that is subject to the same central and peripheral tolerance mechanisms that control reactivity against self. In this case, the unusually high frequency of naive T cells able to recognize and respond against non-self-allogeneic major histocompatibility complex (MHC) antigens leads to an exceptionally large pool of pathogenic effector lymphocytes that must be controlled if graft rejection is to be avoided. A great deal of effort has been directed toward understanding the role of clonal anergy and/or active immunoregulation in the induction of peripheral transplantation tolerance but, until recently, relatively little progress had been made towards defining the potential contribution of clonal deletion. Here, we outline recent data that define a clear requirement for deletion in the induction of peripheral transplantation tolerance across MHC barriers, and discuss the potential implications of these results in the context of current treatment modalities used in the clinical transplantation setting