Nucleon Axial Form Factor from Lattice QCD

Results for the isovector axial form factors of the proton from a lattice QCD calculation are presented for both point-split and local currents. They are obtained on a quenched $16^{3} \times 24$ lattice at $\beta= 6.0$ with Wilson fermions for a range of quark masses from strange to charm. We determine the finite lattice renormalization for both the local and point-split currents of heavy quarks. Results extrapolated to the chiral limit show that the $q^2$ dependence of the axial form factor agrees reasonably well with experiment. The axial coupling constant $g_A$ calculated for the local and the point-split currents is about 6\% and 12\% smaller than the experimental value respectively.Comment: 8 pages, 5 figures (included in part 2), UK/93-0

Origins of the Ambient Solar Wind: Implications for Space Weather

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

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

Austenitizing and microstructure of a HT-9 steel

The effects of austenitizing temperatures and times on the microstructure of a 12Cr-1Mo-V-W steel are reported. Austenitizing temperatures covering the range of 900 to 1225/sup 0/C and times of 30 minutes to 100 hours were used. Equilibrium microstructures were difficult to obtain because delta ferrite initially present in the steel resists dissolution during austenitizing. 10 figures

Toward operational criteria for ecosystem approaches to health

More than a decade has passed since Forget and Lebel (2001)introduced the ‘‘ecosystem approach to human health’’. Since this first conceptual elaboration, a significant literature has developed describing validity, utility, and general guidelines for a newly emerging research community. Numerous initiatives, many supported by Canada’s International Development Research Center (IDRC), ranging from narrowly focused research studies to large-scale interventions, have focused on health challenges within diverse social-ecological settings. We note that while ‘‘ecohealth’’ was first introduced as a fusion of the ‘‘ecosystem approach to human health’’, inthe following abbreviated as ‘‘ecosystem approach’’, and IDRC’s ‘‘ecohealth program’’, the term is also used in a more generic way. For example, in naming this journal, ecohealth was suggested to broadly include research and practice addressing problems at the interface of the ecological and health sciences (Wilcox et al. 2004; Wilcox et al. 2012).However, ideas of applying the ecosystem concept to human health and that of ‘‘healthy ecosystems’’ have always been at the core of research, dialog and, to our knowledge, most activities and events using the term ecohealth. Other initiatives not directly sponsored by IDRC have also endorsed the idea of ecosystem approaches to health (e.g.PAHO 2009), and applications of the ‘‘one health’’ concept increasingly incorporate an ecosystem perspective (Zinsstag2012). Yet, the operational specifics of the ecosystem approach have been difficult to define, which hampers comparability even among similar interventions, the evaluation of efficacy, and the development of best practices targeting both communal health benefits and procedural efficiencies. We believe more can be done in this regard and present this paper with the following two aims: (1) to derive a set of operational criteria specifically applicable to ecosystem approaches and (2) to offer a protocol derived from our combined experiences and a thorough literature review to suggest an evidence-based best practice technique for the procedural implementation of ecosystem approaches