van der Waals coefficients for positronium-atom interactions

The van der Waals coefficients for positronium interactions with a number of rare gases (He, Ne, Ar, Kr, and Xe) and alkali-metal atoms (Li, Na, K, and Rb) are estimated using a variety of ab initio and semiempirical methods. Dispersion coefficients are also presented for atomic hydrogen and a number of rare-gas and alkali-metal atoms for validation purposes

The political nexus between water and economics in Brazil:A critique of recent policy reforms

The reform of water policies in Brazil has involved a combination of regulatory norms and economic-incentive instruments. Nonetheless, contrary to its formal objectives, the process has largely failed to prevent widespread environmental impacts and growing spatial and sectoral conflicts. The main reason for such failures is the perverse influence of market rationality, which is particularly evident in the reorganization of the public sector, the quantification of the monetary value of water, and the payment for environmental services

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

LPA Brief No. 1. Institutions, governance and incentives in common property regimes for African rangelands

About 14 % of the world's cattle and 21 % of its sheep and goats are found in Africa on a land base that comprises 25 % of the world's total area of rangelands. Most of these rangelands are or have in the past been managed under traditional systems of communal tenure. Regrettably, the wide variety of institutional arrangements, structures of governance and incentives that characterise these common property regimes have not been well understood or been the subject of much analysis. This paper attempts to fill part of this knowledge gap by providing a framework for the analysis of common property rangeland regimes on the basis of some selected examples in Africa

Co-management or no management: The prospects for internal governance of common property regimes through dynamic contracts

It has been suggested that African rangelands would be utilized and managed on a more sustainable and profitable basis if they were governed by co-management arrangements, with state governments defining group rights and governing inter-group interactions and local organizations governing interactions among members within particular groups. In this paper we develop a discrete-time dynamic model of a rangeland to investigate the possibilities for internal management of resource use interactions within a common property regime. We find that there can be effective internal management without any formal institutional structure within the regime if: (1) group members are confident that the boundaries of the regime will be effectively protected; (2) the group of resources users is kept relatively small; (3) future pasture potential is not overly sensitive to changes in the current stocking rate; and (4) individuals do not discount future payoffs too heavily