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In the 2015 review paper ‘Petawatt Class Lasers Worldwide’ a comprehensive overview of the current status of high-power facilities of
was presented. This was largely based on facility specifications, with some description of their uses, for instance in fundamental ultra-high-intensity interactions, secondary source generation, and inertial confinement fusion (ICF). With the 2018 Nobel Prize in Physics being awarded to Professors Donna Strickland and Gerard Mourou for the development of the technique of chirped pulse amplification (CPA), which made these lasers possible, we celebrate by providing a comprehensive update of the current status of ultra-high-power lasers and demonstrate how the technology has developed. We are now in the era of multi-petawatt facilities coming online, with 100 PW lasers being proposed and even under construction. In addition to this there is a pull towards development of industrial and multi-disciplinary applications, which demands much higher repetition rates, delivering high-average powers with higher efficiencies and the use of alternative wavelengths: mid-IR facilities. So apart from a comprehensive update of the current global status, we want to look at what technologies are to be deployed to get to these new regimes, and some of the critical issues facing their development.
A national need is to prepare for and respond to accidental or intentional disasters categorized as chemical, biological, radiological, nuclear, or explosive (CBRNE). These incidents require specific subject-matter expertise, yet have commonalities. We identify 7 core elements comprising CBRNE science that require integration for effective preparedness planning and public health and medical response and recovery. These core elements are (1) basic and clinical sciences, (2) modeling and systems management, (3) planning, (4) response and incident management, (5) recovery and resilience, (6) lessons learned, and (7) continuous improvement. A key feature is the ability of relevant subject matter experts to integrate information into response operations. We propose the CBRNE medical operations science support expert as a professional who (1) understands that CBRNE incidents require an integrated systems approach, (2) understands the key functions and contributions of CBRNE science practitioners, (3) helps direct strategic and tactical CBRNE planning and responses through first-hand experience, and (4) provides advice to senior decision-makers managing response activities. Recognition of both CBRNE science as a distinct competency and the establishment of the CBRNE medical operations science support expert informs the public of the enormous progress made, broadcasts opportunities for new talent, and enhances the sophistication and analytic expertise of senior managers planning for and responding to CBRNE incidents.
The role that vitamin D plays in pulmonary function remains uncertain. Epidemiological studies reported mixed findings for serum 25-hydroxyvitamin D (25(OH)D)–pulmonary function association. We conducted the largest cross-sectional meta-analysis of the 25(OH)D–pulmonary function association to date, based on nine European ancestry (EA) cohorts (n 22 838) and five African ancestry (AA) cohorts (n 4290) in the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium. Data were analysed using linear models by cohort and ancestry. Effect modification by smoking status (current/former/never) was tested. Results were combined using fixed-effects meta-analysis. Mean serum 25(OH)D was 68 (sd 29) nmol/l for EA and 49 (sd 21) nmol/l for AA. For each 1 nmol/l higher 25(OH)D, forced expiratory volume in the 1st second (FEV1) was higher by 1·1 ml in EA (95 % CI 0·9, 1·3; P<0·0001) and 1·8 ml (95 % CI 1·1, 2·5; P<0·0001) in AA (Prace difference=0·06), and forced vital capacity (FVC) was higher by 1·3 ml in EA (95 % CI 1·0, 1·6; P<0·0001) and 1·5 ml (95 % CI 0·8, 2·3; P=0·0001) in AA (Prace difference=0·56). Among EA, the 25(OH)D–FVC association was stronger in smokers: per 1 nmol/l higher 25(OH)D, FVC was higher by 1·7 ml (95 % CI 1·1, 2·3) for current smokers and 1·7 ml (95 % CI 1·2, 2·1) for former smokers, compared with 0·8 ml (95 % CI 0·4, 1·2) for never smokers. In summary, the 25(OH)D associations with FEV1 and FVC were positive in both ancestries. In EA, a stronger association was observed for smokers compared with never smokers, which supports the importance of vitamin D in vulnerable populations.
Lateral memristors consisting of planar Ag electrodes (with sub-micrometer separation) supported on thin films of amorphous zinc-tin-oxide have been characterized. After an initial filament-forming process, each device exhibited volatile, resistive switching. In the low resistance state, the transport mechanism and conductance depended on prior activity and on the imposed current limit, mimicking biologic synaptic plasticity. Microscopic observations performed on each device revealed nanoscale filaments between the electrodes. These filaments were subject to Rayleigh instability and exhibited relaxation times determined by their effective radii. The relaxation times and on:off resistance ratios suggest suitability for threshold switching selector devices.
Making replication studies widely conducted and published requires new incentives. Academic awards can provide such incentives by highlighting the best and most important replications. The Organization for Human Brain Mapping (OHBM) has led such efforts by recently introducing the OHBM Replication Award. Other communities can adopt this approach to promote replications and reduce career cost for researchers performing them.
Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88) presented a critique of our recently published paper in Cell Reports entitled ‘Large-Scale Cognitive GWAS Meta-Analysis Reveals Tissue-Specific Neural Expression and Potential Nootropic Drug Targets’ (Lam et al., Cell Reports, Vol. 21, 2017, 2597–2613). Specifically, Hill offered several interrelated comments suggesting potential problems with our use of a new analytic method called Multi-Trait Analysis of GWAS (MTAG) (Turley et al., Nature Genetics, Vol. 50, 2018, 229–237). In this brief article, we respond to each of these concerns. Using empirical data, we conclude that our MTAG results do not suffer from ‘inflation in the FDR [false discovery rate]’, as suggested by Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88), and are not ‘more relevant to the genetic contributions to education than they are to the genetic contributions to intelligence’.
Insects of the family Nabidae (Hemiptera) are generalist predators commonly found in agroecosystems, but little is known about their predation rates on common pests of forage crops. We determined the functional response and prey preference of Nabis Latreille species to two common leafhopper pests of red clover (Trifolium pratense Linnaeus; Fabaceae): Agallia constricta Van Duzee (Hemiptera: Cicadellidae) and Ceratagallia agricola (Hamilton) (Hemiptera: Cicadellidae). We also determined the survivorship of A. constricta to predation by Nabis species over the course of five days. The Nabis species displayed a Type III functional response to both leafhopper species with a preference for A. constricta. The 10-A. constricta/cage treatments and 20-A. constricta/cage treatments had the highest survival probabilities after five days with survival probabilities of 0.19 and 0.23, respectively. These results indicate that Nabis species may help in controlling leafhopper populations in forage-crop systems.
It has been hypothesized that there are significant dissolved organic matter (DOM) pools in sea-ice systems, although measurements of DOM in sea ice have only rarely been made. The significance of DOM for ice-based productivity and carbon turnover therefore remains highly speculative. DOM within sea ice from the Amundsen and Bellingshausen Seas, Antarctica, in 1994 and the Weddell Sea, Antarctica, in 1992 and 1997 was investigated. Measurements were made on melted sea-ice sections in 1994 and 1997 and in sea-ice brines in 1992. Dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) concentrations in melted ice cores were up to 1.8 and 0.78 mM, respectively, or 30 and 8 times higher than those in surface water concentrations, respectively. However, when concentrations within the brine channel/pore space were calculated from estimated brine volumes, actual concentrations of DOC in brines were up to 23.3 mM and DON up to 2.2 mM, although mean values were 1.8 and 0.15 mM, respectively. There were higher concentrations of DOM in warm, porous summer second-year sea ice compared with colder autumn first-year ice, consistent with the different biological activity supported within the various ice types. However, in general there was poor correlation between DOC and DON with algal biomass and numbers of bacteria within the ice. The mean DOC/DON ratio was 11, although again values were highly variable, ranging from 3 to highly carbon-enriched samples of 95. Measurements made on a limited dataset showed that carbohydrates constitute on average 35% of the DOC pool, with highly variable contributions of 1−99%.
It is well established that during sea-ice formation, crystals aggregate into a solid matrix, and dissolved sea-water constituents, including inorganic nutrients, are rejected from the ice matrix. However, the behaviour of dissolved organic matter (DOM) during ice formation and growth has not been studied to date. DOM is the primary energetic substrate for microbial heterotrophic activity in sea water and sea ice, and therefore it is at the base of the trophic fluxes within the microbial food web. The aim of our study was to compare the behaviour of DOM and inorganic nutrients during formation and growth of sea ice. Experiments were conducted in a large indoor ice-tank facility (Hamburg Ship Model Basin, Germany) at −15°C. Three 1 m3 tanks, to which synthetic sea water, nutrients and dissolved organic compounds (diatom-extracted DOM) had been added, were sampled over a period of 5 days during sea-ice formation. Samples were collected throughout the experiment from water underlying the ice, and at the end from the ice as well. Brine was obtained from the ice by centrifuging ice cores. Inorganic nutrients (nitrate and phosphate) were substantially enriched in brine in comparison to water and ice phases, consistent with the processes of ice formation and brine rejection. Dissolved organic carbon (DOC) was also enriched in brine but was more variable and enriched in comparison to a dilution line. No difference in bacteria numbers was observed between water, ice and brine. No bacteria growth was measured, and this therefore had no influence on the measurable DOC levels. We conclude that the incorporation of dissolved organic compounds in newly forming ice is conservative. However, since the proportions of DOC in the brine were partially higher than those of the inorganic nutrients, concentrating effects of DOC in brine might be different compared to salts.
Ice-core and snow data from the Amundsen, Bellingshausen and Weddell Seas, Antarctica, show that the formation of superimposed ice and the development of seawater-filled gap layers with high algal standing stocks is typical of the perennial sea ice in summer. The coarse-grained and dense snow had salinities mostly below 0.1‰. A layer of fresh superimposed ice had a mean thickness of 0.04–0.12 m. Gap layers 0.04–0.08 m thick extended downwards from 0.02 to 0.14 m below the water level. These gaps were populated by diatom standing stocks up to 439 μg L−1 chlorophyll a. We propose a comprehensive heuristic model of summer processes, where warming and the reversal of temperature gradients cause major transformations in snow and ice properties. The warming also causes the reopening of incompletely frozen slush layers caused by flood-freeze cycles during winter. Alternatively, superimposed ice forms at the cold interface between snow and slush in the case of flooding with negative freeboard. Combined, these explain the initial formation of gap layers by abiotic means alone. The upward growth of superimposed ice above the water level competes with a steady submergence of floes due to bottom and internal melting and accumulation of snow.
The behavior of majorions, δ18O, dissolved organic carbon (DOC) and trace elements was studied during the initial freezing of low-saline water (3 practical salinity units) in a freezing experiment. Samples were also collected from first-year sea ice from pack ice in the Bothnian Bay, northern Baltic Sea. During initial ice formation, the major-ion ratios in sea ice indicated variable behavior, with some ions showing relative enrichment (sulfate, calcium and magnesium), conservative behavior (sodium) or relative depletion (potassium) compared to sea water at the same salinity. DOC, iron and aluminum showed enrichment in the ice, while zinc was depleted to salinity. Lead was detected in surface snow-ice layers only, implying atmospheric accumulation. First-year sea ice, with a variable growth and thermal history, showed behavior for major ions similar to that observed in new ice. However, for trace elements the picture was much more complicated, most likely due to active secondary processes such as atmospheric supply and biological activity. Ice growth has a potential impact on the chemical budgets and cycling of some elements, especially those which are selectively rejected/retained during sea-ice formation, particularly in the shallow parts of the Bothnian Bay covered with a land-fast ice cover.
Critical to the development of improved HIV elimination efforts is a greater understanding of how social networks and their dynamics are related to HIV risk and prevention. In this paper, we examine network stability of confidant and sexual networks among young black men who have sex with men (YBMSM). We use data from uConnect (2013–2016), a population-based, longitudinal cohort study. We use an innovative approach to measure both sexual and confidant network stability at three time points, and examine the relationship between each type of stability and HIV risk and prevention behaviors. This approach is consistent with a co-evolutionary perspective in which behavior is not only affected by static properties of an individual's network, but may also be associated with changes in the topology of his or her egocentric network. Our results indicate that although confidant and sexual network stability are moderately correlated, their dynamics are distinct with different predictors and differing associations with behavior. Both types of stability are associated with lower rates of risk behaviors, and both are reduced among those who have spent time in jail. Public health awareness and engagement with both types of networks may provide new opportunities for HIV prevention interventions.
Whether genetic factors influence the associations of fatty acids with the risk of sudden cardiac arrest (SCA) is largely unknown. To investigate possible gene–fatty acid interactions on SCA risk, we used a case-only approach and measured fatty acids in erythrocyte samples from 1869 SCA cases in a population-based repository with genetic data. We selected 191 SNP in ENCODE-identified regulatory regions of fifty-five candidate genes in fatty acid metabolic pathways. Using linear regression and additive genetic models, we investigated the association of the selected SNP with erythrocyte levels of fatty acids, including DHA, EPA and trans-fatty acids among the SCA cases. The assumption of no association in non-cases was supported by analysis of publicly available datasets containing over 8000 samples. None of the SNP–fatty acid associations tested among the cases reached statistical significance after correction for multiple comparisons. One SNP, rs4654990 near PLA2G2A, with an allele frequency of 0·33, was nominally associated with lower levels of DHA and EPA and higher levels of trans-fatty acids. The strongest association was with DHA levels (exponentiated coefficient for one unit (1 % of total fatty acids), 0·90, 95 % CI 0·85, 0·97; P = 0·003), indicating that for subjects with a coded allele, the OR of SCA associated with one unit higher DHA is about 90 % what it is for subjects with one fewer coded allele. These findings suggest that the associations of circulating n-3 and trans-fatty acids with SCA risk may be more pronounced in carriers of the rs4654990 G allele.
Evolutionary stasis has often been explained by stabilizing selection, intrinsic constraints, or, more recently, by spatially patterned population dynamics. To distinguish which of these mechanisms explains a given case of stasis in the fossil record, stasis must first be rigorously documented in a high-resolution stratigraphic time series of fossil specimens. Furthermore, past studies of evolutionary mode in fossil mammalian lineages have often been limited to univariate traits (e.g., molar crown area). It is reasonable to assume that tooth shape, a multivariate trait, reflects important additional aspects of tooth form and function. Here we present the results of a geometric morphometric analysis of the lower dentition of the Paleocene-Eocene condylarth species Ectocion osbornianus collected from the Bighorn and Clarks Fork Basins of northwestern Wyoming. Tooth margin shape, cusp configuration, and shearing crest shape were digitized for the last lower premolar, p4, and for two lower molars, m1 and m3. Multivariate statistical tests of evolutionary mode were used to analyze the change in shape variance over time in addition to the magnitude and direction of shape change. Test results characterize the shape time series as consisting of counteracting changes with less change than expected under a random walk (i.e., stasis). The temporal structure of shape variance implies that the sampled E. osbornianus most likely represent a single population, which is not concordant with the population dynamic mechanism of stasis. Stabilizing selection and/or intrinsic constraints remain as the mechanisms that could explain stasis in the lower dental shape of E. osbornianus despite the variable environmental conditions of the Paleocene–Eocene.
Catalyst development is needed to enable the use of renewable electricity to chemically convert carbon dioxide (CO2) and water into fuels and chemicals, a more sustainable, lower-carbon alternative to conventional processes that produce fuels and chemicals based on fossil resources. In this study, the catalytic activity and selectivity of polycrystalline platinum (Pt) is thoroughly characterized for the CO2 reduction reaction, based on an electrochemical cell design that offers high sensitivity for product detection. Thin polyaniline films are then electrodeposited onto polycrystalline Pt foils to form hybrid organic–inorganic surfaces. The addition of the polymer is observed to have an impact on the catalytic chemistry, yielding up to a fivefold enhancement in formate and CO production over pure Pt foils. This work elucidates new strategies to perturb interfacial chemistry in a manner that could help steer CO2 electro-reduction catalysis in desired directions.