Electronic Structures and Bonding of Oxygen on Plutonium Layers

Oxygen adsorption on delta-Pu (100) and (111) surfaces have been studied at both non-spin-polarized and spin-polarized levels using the generalized gradient approximation of density functional theory (GGA-DFT)with Perdew and Wang functionals. The center position of the (100) surface is found to be the most favorable site with chemisorption energies of 7.386 eV and 7.080 eV at the two levels of theory. The distances of the oxygen adatom from the Pu surface are found to be 0.92A and 1.02A, respectively. For the (111) surface non-spin-polarized calculations, the center position is also the preferred site with a chemisorption energy of 7.070 eV and the distance of the adatom being 1.31A, but for spin-polarized calculations the bridge and the center sites are found to be basically degenerate, the difference in chemisorption energies being only 0.021 eV. In general, due to the adsorption of oxygen, plutonium 5f orbitals are pushed further below the Fermi energy, compared to the bare plutonium layers. The work function, in general, increases due to oxygen adsorption on plutonium surfaces.Comment: Spin-polarization is considered, and the paper is revised accordingl

"The fruits of independence": Satyajit Ray, Indian nationhood and the spectre of empire

Challenging the longstanding consensus that Satyajit Ray's work is largely free of ideological concerns and notable only for its humanistic richness, this article shows with reference to representations of British colonialism and Indian nationhood that Ray's films and stories are marked deeply and consistently by a distinctively Bengali variety of liberalism. Drawn from an ongoing biographical project, it commences with an overview of the nationalist milieu in which Ray grew up and emphasizes the preoccupation with colonialism and nationalism that marked his earliest unfilmed scripts. It then shows with case studies of Kanchanjangha (1962), Charulata (1964), First Class Kamra (First-Class Compartment, 1981), Pratidwandi (The Adversary, 1970), Shatranj ke Khilari (The Chess Players, 1977), Agantuk (The Stranger, 1991) and Robertsoner Ruby (Robertson's Ruby, 1992) how Ray's mature work continued to combine a strongly anti-colonial viewpoint with a shifting perspective on Indian nationhood and an unequivocal commitment to cultural cosmopolitanism. Analysing how Ray articulated his ideological positions through the quintessentially liberal device of complexly staged debates that were apparently free, but in fact closed by the scenarist/director on ideologically specific notes, this article concludes that Ray's reputation as an all-forgiving, ‘everybody-has-his-reasons’ humanist is based on simplistic or even tendentious readings of his work

The Limits and Intensity of Plasmodium falciparum Transmission: Implications for Malaria Control and Elimination Worldwide

Combining extensive surveillance and climate data, as well as biological characteristics of Anopheles mosquitoes, Robert Snow and colleagues create a global map of risk for P. falciparum malaria

Vulnerability to snakebite envenoming: a global mapping of hotspots.

BACKGROUND Snakebite envenoming is a frequently overlooked cause of mortality and morbidity. Data for snake ecology and existing snakebite interventions are scarce, limiting accurate burden estimation initiatives. Low global awareness stunts new interventions, adequate health resources, and available health care. Therefore, we aimed to synthesise currently available data to identify the most vulnerable populations at risk of snakebite, and where additional data to manage this global problem are needed. METHODS We assembled a list of snake species using WHO guidelines. Where relevant, we obtained expert opinion range (EOR) maps from WHO or the Clinical Toxinology Resources. We also obtained occurrence data for each snake species from a variety of websites, such as VertNet and iNaturalist, using the spocc R package (version 0.7.0). We removed duplicate occurrence data and categorised snakes into three groups: group A (no available EOR map or species occurrence records), group B (EOR map but <5 species occurrence records), and group C (EOR map and ≥5 species occurrence records). For group C species, we did a multivariate environmental similarity analysis using the 2008 WHO EOR maps and newly available evidence. Using these data and the EOR maps, we produced contemporary range maps for medically important venomous snake species at a 5 × 5 km resolution. We subsequently triangulated these data with three health system metrics (antivenom availability, accessibility to urban centres, and the Healthcare Access and Quality [HAQ] Index) to identify the populations most vulnerable to snakebite morbidity and mortality. FINDINGS We provide a map showing the ranges of 278 snake species globally. Although about 6·85 billion people worldwide live within range of areas inhabited by snakes, about 146·70 million live within remote areas lacking quality health-care provisioning. Comparing opposite ends of the HAQ Index, 272·91 million individuals (65·25%) of the population within the lowest decile are at risk of exposure to any snake for which no effective therapy exists compared with 519·46 million individuals (27·79%) within the highest HAQ Index decile, showing a disproportionate coverage in reported antivenom availability. Antivenoms were available for 119 (43%) of 278 snake species evaluated by WHO, while globally 750·19 million (10·95%) of those living within snake ranges live more than 1 h from population centres. In total, we identify about 92·66 million people living within these vulnerable geographies, including many sub-Saharan countries, Indonesia, and other parts of southeast Asia. INTERPRETATION Identifying exact populations vulnerable to the most severe outcomes of snakebite envenoming at a subnational level is important for prioritising new data collection and collation, reinforcing envenoming treatment, existing health-care systems, and deploying currently available and future interventions. These maps can guide future research efforts on snakebite envenoming from both ecological and public health perspectives and better target future estimates of the burden of this neglected tropical disease

The disappearing act: a dusty wind eclipsing RW Aur

The authors acknowledge support from the Science and Technology Facilities Council through grants no. ST/K502339/1 and ST/M001296/1, and the Science Foundation Ireland through grant no. 10/RFP/AST2780.RW Aur is a young binary star that experienced a deep dimming in 2010-11in component A and a second even deeper dimming from summer 2014 to summer 2016. We present new unresolved multi-band photometry during the 2014-16 eclipse, new emission line spectroscopy before and during th dimming, archive infrared photometry between 2014-15, as well as an overview of literature data. Spectral observations were carried out witht he Fibre-fed RObotic Dual-beam Optical Spectrograph on the Liverpool Telescope. Photometric monitoring was done with the Las Cumbres Observatory Global Telescope Network and James Gregory Telescope. Ourphotometry shows that RW Aur dropped in brightness to R = 12.5 in March 2016. In addition to the long-term dimming trend, RW Aur is variable on time-scales as short as hours. The short-term variation is most likely due to an unstable accretion flow. This, combined with the presence of accretion-related emission lines in the spectra suggest that accretion flows in the binary system are at least partially visible during the eclipse. The equivalent width of [O I] increases by a factor of ten in 2014, coinciding with the dimming event, confirming previous reports.The blueshifted part of the Hα profile is suppressed during the eclipse. In combination with the increase in mid-infrared brightness during the eclipse reported in the literature and seen in WISE archival data, and constraints on the geometry of the disk around RW Aur A we arrive at the conclusion that the obscuring screen is part of a wind emanating from the inner disc.Publisher PDFPeer reviewe

Effect of Fouling on the Performance of an Instream Turbine

As the tidal energy industry starts to mature towards commercial projects a key focus is on reliable power performance. As for any marine application, fouling poses a potential performance reduction risk for instream turbine deployments. SCHOTTEL HYDRO have developed their current commercial SCHOTTEL Instream Turbines. Four drivetrains with 6.3m rotors were deployed on the surface platform PLAT-I by Sustainable Marine Energy. One of PLAT-Is key features is access to the turbines for inspection and maintenance in situ. The system has undergone sea testing from 2017 to 2021 in Scotland and Nova Scotia (Canada). This paper presents the hydrodynamic rotor performance reduction due to fouling based on full-scale experimental results. An in-house blade element momentum model is used to quantify the changes of the hydrodynamic forces in terms of lift and drag for the hydrofoils used. Furthermore, the effect of fouling on the downstream wake was quantified in the field. The performance reduction due to fouling is significant and leads to a power drop of up to 43%, whereas the thrust is reduced by 25%. This is also reflected in a reduction of the turbine’s downstream wake as a “fouled” rotor extracts less energy from the flow. Modifications of the polar data, used for semi-empirical performance predictions, are able to predict the effect of fouling on the rotor performance. In general, the results derived from the testing prove the significance of access to the turbines in order to avoid reduction in the turbines’ performance due to fouling

A density functional study of molecular oxygen adsorption and reaction barrier on Pu (100) surface

Oxygen molecule adsorptions on a Pu (100) surface have been studied in detail, using the generalized gradient approximation to density functional theory. Dissociative adsorption with a layer by layer alternate spin arrangement of the plutonium layer is found to be energetically more favorable compared to molecular adsorption. Hor2 approach on a bridge site without spin polarization was found to the highest chemisorbed site with energy of 8.787 eV among all the cases studied. The second highest chemisorption energy of 8.236 eV, is the spin-polarized Hor2 or Ver approach at center site. Inclusion of spin polarization affects the chemisorption processes significantly, non-spin-polarized chemisorption energies being typically higher than the spin-polarized energies. We also find that the 5f electrons to be more localized in spin-polarized cases compared to the non-spin-polarized counterparts. The ionic part of O-Pu bonding plays a significant role, while the Pu 5f-O 2p hybridization was found to be rather week. Also, adsorptions of oxygen push the top of 5f band deeper away from the Fermi level, indicating further bonding by the 5f orbitals might be less probable. Except for the interstitial sites, the work functions increase due to adsorptions of oxygen

Re-examining the effects of verbal instructional type on early stage motor learning

The present study investigated the differential effects of analogy and explicit instructions on early stage motor learning and movement in a modified high jump task. Participants were randomly assigned to one of three experimental conditions: analogy, explicit light (reduced informational load), or traditional explicit (large informational load). During the two-day learning phase, participants learned a novel high jump technique based on the ‘scissors’ style using the instructions for their respective conditions. For the single-day testing phase, participants completed both a retention test and task-relevant pressure test, the latter of which featured a rising high-jump-bar pressure manipulation. Although analogy learners demonstrated slightly more efficient technique and reported fewer technical rules on average, the differences between the conditions were not statistically significant. There were, however, significant differences in joint variability with respect to instructional type, as variability was lowest for the analogy condition during both the learning and testing phases, and as a function of block, as joint variability decreased for all conditions during the learning phase. Findings suggest that reducing the informational volume of explicit instructions may mitigate the deleterious effects on performance previously associated with explicit learning in the literature

Introduction: Interpreting British European Policy

Britain has had particular problems reconciling itself to the idea of being a ‘European’ actor and a wholehearted member of the EEC/EU since 1973. Now, potentially, the ‘awkward partner’, is edging towards the exit door of the EU because a membership referendum is an increasingly likely prospect in the coming years. The aim of this special issue is to consider how we can account for the present state of affairs by adopting an interpretivist perspective on British European policy over the past four decades. The article begins with a comprehensive review of the extant literature on Britain and Europe, and an elaboration of the ‘traditions and dilemmas’ framework within which the contributors have studied the empirical material in their articles. It then explains the major themes that connect the articles and suggests how future research might build on the agenda proposed in this special issue