3,416 research outputs found
Neutral Gas Properties and Ly Escape in Extreme Green Pea Galaxies
Mechanisms regulating the escape of Ly photons and ionizing radiation
remain poorly understood. To study these processes we analyze VLA 21cm
observations of one Green Pea (GP), J160810+352809 (hereafter J1608), and HST
COS spectra of 17 GP galaxies at . All are highly ionized: J1608 has the
highest [O III] /[O II] for star-forming galaxies in
SDSS, and the 17 GPs have [O III]/[O II] . We set an upper limit on
J1608's HI mass of , near or below average compared to
similar mass dwarf galaxies. In the COS sample, eight GPs show Ly
absorption components, six of which also have Ly emission. The HI
column densities derived from Ly absorption are high, cm, well above the LyC optically thick limit. Using
low-ionization absorption lines, we measure covering fractions
(f_{\mbox{cov}}) of , and find that f_{\mbox{cov}} strongly
anti-correlates with Ly escape fraction. Low covering fractions may
facilitate Ly and LyC escape through dense neutral regions. GPs with
f_{\mbox{cov}}\sim1 all have low neutral gas velocities, while GPs with lower
f_{\mbox{cov}}=0.2-0.6 have a larger range of velocities. Conventional
mechanical feedback may help establish low f_{\mbox{cov}} in some cases,
whereas other processes may be important for GPs with low velocities. Finally,
we compare f_{\mbox{cov}} with proposed indicators of LyC escape. Ionizing
photon escape likely depends on a combination of neutral gas geometry and
kinematics, complicating the use of emission-line diagnostics for identifying
LyC emitters.Comment: 21 pages, 11 figures, accepted for publication in Ap
Masculinity and men's health disparities: conceptual and theoretical challenges
In the field of menâs health, including the important emerging area of menâs health disparities, conceptual and theoretical assumptions and challenges are omnipresent. These assumptions and challenges come from a range of disciplinary backgrounds. Biological, sociobiological, psychological, and sociological explanations are all found as either implicit or explicit explanations for understanding menâs health practices and outcomes. At the forefront of many of these assumptions and challenges have been discussions around how masculinitiesâdiffering ways of being a manâinfluence menâs practices and subsequent health outcomes. Many of these discussions have also included exchanges on how masculinities interact with other identity issuesâincluding class, ethnicity, sexuality, disability, and ageâto influence menâs varied health and social practices
âLetâs duck out of the windâ: operationalising intersectionality to understand elderly menâs caregiving experiences
This paper aims is to demonstrate how Bourdieuâs conceptual tools of habitus, capital and field can facilitate the operationalisation of intersectionality. Following an appreciation of the methodological issues arising from the practical application of intersectionality, we introduce data from an Australian study of husbands caring for wives with dementia. With care often being constructed as a feminine practice, menâs caregiving experiences are frequently said to be in tension with many hegemonic masculine practices. However, men are not homogenous, rather their experiences are shaped by intersections of gender, age, class and other identity-defining categories. To help explore some of these intersections, 16 interviews, six of which were enhanced by photo-elicitation methods, were undertaken with a purposive sample of retired husbands caring for a spouse with dementia. Thematic analysis was then employed. In this paper, we present data and themes relating to the husbandâs experiences around independence and self-sufficiency and coping strategies and emotional autonomy. However, the main purpose of the paper is not to focus on these empirical findings per se. Rather, we draw on these data to illustrate how Bourdieuâs work was utilised to help address some of the concerns that have been encountered when applying intersectional theory to empirical research; that is to say, this is primarily a methodological paper. The empirical findings highlight the complex and class influenced ways that husband carers look to sustain independence and autonomy. They further illustrate how the cultural capital accrued through past experiences facilitates or restrains coping mechanisms and associated emotional autonomy during their caregiving journeys. Methodologically, we use these empirical data to demonstrate how Bourdieuâs notions of habitus, capital and field can overcome three specific criti-cisms when applying intersectionality in research studies: (1) its supposed inability to adequately address agency and privilege; (2) its apparent lack of a heuristic device illustrating how time, location and context constrain and empower social actors; and (3) an alleged lack of methodological tools to illustrate the interrelated and generative nature of structure and agency
Stepping up on savings
The UK government remains committed to the Climate Change Act 2008, which mandates an 80% reduction in CO2 from 1990 levels by 2050. As part of the strategy of achieving this reduction, all new homes from 2016 will be required to be zero carbon. The 2008 definition required all CO2 emissions to be reduced to zero through on-site means, covering both regulated emissions from heating, cooling, ventilation and lighting and unregulated emissions from household appliances. Embodied carbon from the construction of the building was excluded. In 2009 the concept of Allowable Solutions was introduced, which permits developers to pay for carbon saving achieved elsewhere. For example a developer may offset CO2 emissions against an approved âon, near or offsiteâ scheme, such as a local energy storage solution or an investment into low carbon electricity generation. In 2011, a further major change removed unregulated emissions from the definition
A single mutation in the envelope protein modulates flavivirus antigenicity, stability, and pathogenesis
The structural flexibility or 'breathing' of the envelope (E) protein of flaviviruses allows virions to sample an ensemble of conformations at equilibrium. The molecular basis and functional consequences of virus conformational dynamics are poorly understood. Here, we identified a single mutation at residue 198 (T198F) of the West Nile virus (WNV) E protein domain I-II hinge that regulates virus breathing. The T198F mutation resulted in a ~70-fold increase in sensitivity to neutralization by a monoclonal antibody targeting a cryptic epitope in the fusion loop. Increased exposure of this otherwise poorly accessible fusion loop epitope was accompanied by reduced virus stability in solution at physiological temperatures. Introduction of a mutation at the analogous residue of dengue virus (DENV), but not Zika virus (ZIKV), E protein also increased accessibility of the cryptic fusion loop epitope and decreased virus stability in solution, suggesting that this residue modulates the structural ensembles sampled by distinct flaviviruses at equilibrium in a context dependent manner. Although the T198F mutation did not substantially impair WNV growth kinetics in vitro, studies in mice revealed attenuation of WNV T198F infection. Overall, our study provides insight into the molecular basis and the in vitro and in vivo consequences of flavivirus breathing
B Cell response and mechanisms of antibody protection to West Nile virus
West Nile virus (WNV) has become the principal cause of viral encephalitis in North America since its introduction in New York in 1999. This emerging virus is transmitted to humans via the bite of an infected mosquito. While there have been several candidates in clinical trials, there are no approved vaccines or WNV-specific therapies for the treatment of WNV disease in humans. From studies with small animal models and convalescent human patients, a great deal has been learned concerning the immune response to infection with WNV. Here, we provide an overview of a subset of that information regarding the humoral and antibody response generated during WNV infection
Collisional stability of localized Yb() atoms immersed in a Fermi sea of Li
We establish an experimental method for a detailed investigation of inelastic
collisional properties between ytterbium (Yb) in the metastable
state and ground state lithium (Li). By combining an optical
lattice and a direct excitation to the state we achieve high
selectivity on the collisional partners. Using this method we determine
inelastic loss coefficients in collisions between
Yb() with magnetic sublevels of and and
ground state Li to be
and , respectively. Absence
of spin changing processes in Yb()-Li inelastic collisions at
low magnetic fields is confirmed by inelastic loss measurements on the
state. We also demonstrate that our method allows us to look into loss
processes in few-body systems separately.Comment: 12 pages, 7 figure
Synthetic fosmidomycin analogues with altered chelating moieties do not inhibit 1-deoxy-D-xylulose 5-phosphate reductoisomerase or Plasmodium falciparum growth in vitro
Fourteen new fosmidomycin analogues with altered metal chelating groups were prepared and evaluated for inhibition of E. coli Dxr, M. tuberculosis Dxr and the growth of P. falciparum K1 in human erythrocytes. None of the synthesized compounds showed activity against either enzyme or the Plasmodia. This study further underlines the importance of the hydroxamate functionality and illustrates that identifying effective alternative bidentate ligands for this target enzyme is challenging
- âŠ