443 research outputs found
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Stab Sensitivity of Energetic Nanolaminates
This work details the stab ignition, small-scale safety, and energy release characteristics of bimetallic Al/Ni(V) and Al/Monel energetic nanolaminate freestanding thin films. The influence of the engineered nanostructural features of the energetic multilayers is correlated with both stab initiation and small-scale energetic materials testing results. Structural parameters of the energetic thin films found to be important include the bi-layer period, total thickness of the film, and presence or absence of aluminum coating layers. In general the most sensitive nanolaminates were those that were relatively thick, possessed fine bi-layer periods, and were not coated. Energetic nanolaminates were tested for their stab sensitivity as freestanding continuous parts and as coarse powders. The stab sensitivity of mock M55 detonators loaded with energetic nanolaminate was found to depend strongly upon both the particle size of the material and the configuration of nanolaminate material, in the detonator cup. In these instances stab ignition was observed with input energies as low as 5 mJ for a coarse powder with an average particle dimension of 400 {micro}m. Selected experiments indicate that the reacting nanolaminate can be used to ignite other energetic materials such as sol-gel nanostructured thermite, and conventional thermite that was either coated onto the multilayer substrate or pressed on it. These results demonstrate that energetic nanolaminates can be tuned to have precise and controlled ignition thresholds and can initiate other energetic materials and therefore are viable candidates as lead-free impact initiated igniters or detonators
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Sacrificing their Careers for their Families? An Analysis of the Family Pay Penalty in Europe
This paper examines the extent of and the mechanisms behind the penalty to motherhood in six European countries. Each country provides different levels of support for maternal employment allowing us to determine institutional effects on labour market outcome. While mothers tend to earn less than non-mothers, the penalty to motherhood is considerably lower in countries with policy support for working mothers. The paper establishes the United Kingdom and West Germany to have the least policy support for working mothers as well as the largest penalties to motherhood
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Public service markets: their economics, institutional oversight and regulation
Public services in the UK have been transformed over the past 25 years with the introduction of market oriented solutions into their provision. This has been characterised by a shift away from state provision to independent providers, and by the introduction of competition and choice. This shift was partly ideologically motivated and partly driven by budget cutting considerations following the financial crisis. As such it has been lacking a comprehensive economic justification or method of analysis. It is now commonly accepted that the language of economic markets is essential to frame arguments about how effectively public services are achieving their intended outcomes.
Using market language and concepts may not always be comfortable for those from a traditional policy-making background. It can nevertheless be very useful when designing investigations into the effectiveness and value for money in the mechanisms of delivery of such services, whenever these services entail a degree of user choice as is currently the case in large parts of health, social care and education (referred to as competition in the market). Our paper wants to provide a conceptual basis on the way of thinking in these terms. We provide a description of the current state and then comment on the desirability of this quasi market approach. Uniquely in the literature, we analyse the expected and desired developments by distinguishing between choice and compulsory merit goods.
In choice merit goods markets many users are unable to choose effectively because of the existence of a number of demand side or supply side market failures. Moreover, conflicts may exist between how service users actually make choices, and policy objectives such as universality or equity which may not be achieved simply by âleaving it to the marketâ.
The users of compulsory merit goods are typically a minority and unable to internalise the full social benefits of their actions; hence it may be welfare-enhancing for society to coerce them âconsumeâ these services. As choice cannot be an objective, the commissioning (competition for the market) or direct provision by the state of such goods may meet public policy objectives more effectively than the market mechanism alone.
Building on these foundations the paper discusses when public service markets are likely to be an effective method of achieving public policy objectives, and when they may not be. Our paper analyses the implications for the institutional and legal framework, funding oversight and regulation of public service markets as a result of their transformation into quasi-markets. The paper concludes with some suggestions for those charged with overseeing public service markets in practice based on this analysis
Post-COVID-19 condition and persisting symptoms in English schoolchildren: repeated surveys to March 2022
BACKGROUND: Both post-COVID-19 condition (long COVID) and the presence of persisting symptoms that do not meet formal definitions of post-COVID-19-condition may adversely affect quality of life and function. However, their prevalence among children and young people in England is unclear. METHODS: We used data from repeated surveys in a large cohort of English schoolchildren from the COVID-19 Schools Infection Survey (SIS) for the school year 2021/22 to describe the weighted prevalence of post-COVID-19-condition and compare persisting symptoms between individuals with a positive SARS-CoV-2 test and those with neither a positive test history nor suspected infection. RESULTS: Among 7797 children from 173 schools, 1.8% of primary school pupils (aged 4 to 11Â years), 4.5% of secondary school pupils in years 7-11 (aged 11 to 16Â years) and 6.9% of those in years 12-13 (aged 16 to 18Â years) met a definition of post-COVID-19 condition in March 2022. Specific persisting symptoms such as anxiety or difficulty concentrating were frequently reported regardless of prior infection status and increased with age: 48.0% of primary school pupils, 52.9% of secondary school pupils in years 7-11 and 79.5% in years 12-13 reporting at least one symptom lasting more than 12Â weeks. Persisting loss of smell and taste, cardiovascular and some systemic symptoms were more frequently reported by those with a previous positive test. CONCLUSIONS: We showed that ongoing symptoms were frequently reported by English schoolchildren regardless of SARS-CoV-2 test results and some specific symptoms such as loss of smell and taste were more prevalent in those with a positive test history. Our study emphasises the wide-ranging impacts of the COVID-19 pandemic on the health and wellbeing of children and young people
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Synthesis of Mesostructured Copper Sulfide by Cation Exchange and Liquid Crystal Templating
The development of synthetic pathways to yield advanced functional materials is an important aspect of materials science. In particular, the ability to control and manipulate the chemical composition and structure of inorganic nanomaterials is highly desirable. Two synthetic approaches which show great promise for producing the next generation of functional inorganic nanomaterials are (1) templating of supramolecular assemblies and (2) ion exchange within nanostructured inorganic solids to manipulate chemical composition. Templating of supramolecular assemblies of surfactants and amphiphilic polymers has already proven to be a powerful technique in synthesizing various inorganic structures. Namely, numerous examples of mesostructured metal oxides (SiO{sub 2}, TiO{sub 2}, WO{sub 3}, etc.) have been synthesized by templating the liquid crystalline phases of amphiphilic polymers and surfactants (i.e. vesicles, 2D and 3D hexagonal and cubic phases, etc.) with inorganic precursors, resulting in the formation of highly ordered inorganic-organic hybrid materials. Although the templating of supramolecular assemblies has been successful in generating highly ordered mesostructured metal oxides, there are only a few examples of non-oxidic mesostructured inorganic materials. The recent developments of ion exchange within nanoparticles offer a promising approach to generating novel nanostructured inorganic materials with unique chemical compositions. Konenkamp et al. and Alivisatos et al. have successfully utilized the ion exchange methods to fully transform the chemical composition of simple nanostructured inorganic materials while retaining their shapes. Although the exact mechanism by which the ions exchange while retaining the overall structure is still unclear, this approach combined with templating of supramolecular assemblies can provide a potent technique for obtaining highly ordered inorganic materials with unique structures and chemical compositions. Herein, we describe for the first time, the successful synthesis of highly ordered, mesostructured Cu{sub x}S, by combining the templating of the supramolecular assemblies of non-ionic amphiphilic polymer method with the cation exchange method to transform mesostructured cadmium sulfide (CdS) into mesostructured copper sulfides (CuS, Cu{sub 2}S)
Optimization of canopy conductance models from concurrent measurements of sap flow and stem water potential on Drooping Sheoak in South Australia
This project is supported by National Centre for Groundwater Research and Training (NCGRT, Australia). The ïŹrst author is supported by China Scholarship Council and NCGRT for his PhD study at Flinders University of South Australia. Xiang Xu and Yunhui Guo provided assistance in the ïŹeld. Constructive comments and suggestion from three anonymous reviewers signiïŹcantly improve the manuscript. This article also appears in: Patterns in Soil-Vegetation-Atmosphere Systems: Monitoring, Modelling and Data Assimilation.Peer reviewedPublisher PD
Evaporation from Pinus caribaea plantations on former grassland soils under maritime tropical conditions.
Wet canopy and dry canopy evaporation from young and mature plantations of Pinus caribaea on former grassland soils under maritime tropical conditions in southwestern Viti Levu, Fiji, were determined using micrometeorological and hydrological techniques. Modeled annual evaporation totals (ET) of 1926 and 1717 mm were derived for the 6- and the 15-year-old stands, respectively. Transpiration made up 72 and 70 of annual ET, and modeled rainfall interception by the trees and litter layer was 20-22 and 8-9 in the young and the mature stands respectively. Monthly ET was related to forest leaf area index and was much higher than that for the kind of tall fire-climax Pennisetum polystachyon grassland replaced by the forests. Grassland reforestation resulted in a maximum decrease in annual water yield of 1180 mm on a plot basis, although it is argued that a reduction of (at least) 500-700 mm would be more realistic at the catchment scale. The impact of reforesting grassland on the water resources in southwest Viti Levu is enhanced by its location in a maritime, seasonal climate in the outer tropics, which favors a larger difference between annual forest and grassland evaporation totals than do equatorial regions
Treatment of autosomal dominant hypocalcemia Type 1 with the calcilytic NPSP795 (SHP635)
Autosomal dominant hypocalcemia type 1 (ADH1) is a rare form of hypoparathyroidism caused by heterozygous, gainâofâfunction mutations of the calciumâsensing receptor gene (CAR). Individuals are hypocalcemic with inappropriately low parathyroid hormone (PTH) secretion and relative hypercalciuria. Calcilytics are negative allosteric modulators of the extracellular calcium receptor (CaR) and therefore may have therapeutic benefits in ADH1. Five adults with ADH1 due to 4 distinct CAR mutations received escalating doses of the calcilytic compound NPSP795 (SHP635) on 3 consecutive days. Pharmacokinetics, pharmacodynamics, efficacy, and safety were assessed. Parallel in vitro testing with subject CaR mutations assessed the effects of NPSP795 on cytoplasmic calcium concentrations (Ca2+i), and ERK and p38MAPK phosphorylation. These effects were correlated with clinical responses to administration of NPSP795. NPSP795 increased plasma PTH levels in a concentrationâdependent manner up to 129% above baseline (p=0.013) at the highest exposure levels. Fractional excretion of calcium (FECa) trended down but not significantly so. Blood ionized calcium levels remained stable during NPSP795 infusion despite fasting, no calcitriol and little calcium supplementation. NPSP795 was generally safe and wellâtolerated. There was significant variability in response clinically across genotypes. In vitro, all mutant CaRs were halfâmaximally activated (EC50) at lower concentrations of extracellular calcium (Ca2+o) compared to wild type (WT) CaR; NPSP795 exposure increased the EC50 for all CaR activity readouts. However, the in vitro responses to NPSP795 did not correlate with any clinical parameters. NPSP795 increased plasma PTH levels in subjects with ADH1 in a doseâdependent manner, and thus, serves as proofâofâconcept that calcilytics could be an effective treatment for ADH1. Albeit all mutations appear to be activating at the CaR, in vitro observations were not predictive of the in vivo phenotype, or the response to calcilytics, suggesting that other parameters impact the response to the drug
Post-COVID-19 condition and persisting symptoms in English schoolchildren: repeated surveys to March 2022
BACKGROUND: Both post-COVID-19 condition (long COVID) and the presence of persisting symptoms that do not meet formal definitions of post-COVID-19-condition may adversely affect quality of life and function. However, their prevalence among children and young people in England is unclear. METHODS: We used data from repeated surveys in a large cohort of English schoolchildren from the COVID-19 Schools Infection Survey (SIS) for the school year 2021/22 to describe the weighted prevalence of post-COVID-19-condition and compare persisting symptoms between individuals with a positive SARS-CoV-2 test and those with neither a positive test history nor suspected infection. RESULTS: Among 7797 children from 173 schools, 1.8% of primary school pupils (aged 4 to 11Â years), 4.5% of secondary school pupils in years 7-11 (aged 11 to 16Â years) and 6.9% of those in years 12-13 (aged 16 to 18Â years) met a definition of post-COVID-19 condition in March 2022. Specific persisting symptoms such as anxiety or difficulty concentrating were frequently reported regardless of prior infection status and increased with age: 48.0% of primary school pupils, 52.9% of secondary school pupils in years 7-11 and 79.5% in years 12-13 reporting at least one symptom lasting more than 12Â weeks. Persisting loss of smell and taste, cardiovascular and some systemic symptoms were more frequently reported by those with a previous positive test. CONCLUSIONS: We showed that ongoing symptoms were frequently reported by English schoolchildren regardless of SARS-CoV-2 test results and some specific symptoms such as loss of smell and taste were more prevalent in those with a positive test history. Our study emphasises the wide-ranging impacts of the COVID-19 pandemic on the health and wellbeing of children and young people
Severe Infection and Risk of Cardiovascular Disease: A Multicohort Study
BACKGROUND: The excess risk of cardiovascular disease associated with a wide array of infectious diseases is unknown. We quantified the short- and long-term risk of major cardiovascular events in people with severe infection and estimated the population-attributable fraction. METHODS: We analyzed data from 331â683 UK Biobank participants without cardiovascular disease at baseline (2006-2010) and replicated our main findings in an independent population from 3 prospective cohort studies comprising 271â533 community-dwelling participants from Finland (baseline 1986-2005). Cardiovascular risk factors were measured at baseline. We diagnosed infectious diseases (the exposure) and incident major cardiovascular events after infections, defined as myocardial infarction, cardiac death, or fatal or nonfatal stroke (the outcome) from linkage of participants to hospital and mortality registers. We computed adjusted hazard ratios (HRs) and 95% CIs for infectious diseases as short- and long-term risk factors for incident major cardiovascular events. We also calculated population-attributable fractions for long-term risk. RESULTS: In the UK Biobank (mean follow-up, 11.6 years), 54â434 participants were hospitalized for an infection, and 11â649 had an incident major cardiovascular event at follow-up. Relative to participants with no record of infectious disease, those who were hospitalized experienced increased risk of major cardiovascular events, largely irrespective of the subtype of infection. This association was strongest during the first month after infection (HR, 7.87 [95% CI, 6.36-9.73]), but remained elevated during the entire follow-up (HR, 1.47 [95% CI, 1.40-1.54]). The findings were similar in the replication cohort (HR, 7.64 [95% CI, 5.82-10.03] during the first month; HR, 1.41 [95% CI, 1.34-1.48] during mean follow-up of 19.2 years). After controlling for traditional cardiovascular risk factors, the population-attributable fraction for severe infections and major cardiovascular events was 4.4% in the UK Biobank and 6.1% in the replication cohort. CONCLUSIONS: Infections severe enough to require hospital treatment were associated with increased risks for major cardiovascular disease events immediately after hospitalization. A small excess risk was also observed in the long-term, but residual confounding cannot be excluded
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