1,616 research outputs found

    American historiography of the origins of World War I, 1914-1935| A comparative study

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    Inconsistency in 9 mm bullets : correlation of jacket thickness to post-impact geometry measured with non-destructive X-ray computed tomography

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    Fundamental to any ballistic armour standard is the reference projectile to be defeated. Typically, for certification purposes, a consistent and symmetrical bullet geometry is assumed, however variations in bullet jacket dimensions can have far reaching consequences. Traditionally, characteristics and internal dimensions have been analysed by physically sectioning bullets – an approach which is of restricted scope and which precludes subsequent ballistic assessment. The use of a non-destructive X-ray computed tomography (CT) method has been demonstrated and validated Kumar et al., 2011); the authors now apply this technique to correlate bullet impact response with jacket thickness variations. A set of 20 bullets (9 mm DM11) were selected for comparison and an image-based analysis method was employed to map jacket thickness and determine the centre of gravity of each specimen. Both intra- and inter-bullet variations were investigated, with thickness variations of the order of 200 um commonly found along the length of all bullets and angular variations of up to 50 um in some. The bullets were subsequently impacted against a rigid flat plate under controlled conditions (observed on a high-speed video camera) and the resulting deformed projectiles were re-analysed. The results of the experiments demonstrate a marked difference in ballistic performance between bullets from different manufacturers and an asymmetric thinning of the jacket is observed in regions of pre-impact weakness. The conclusions are relevant for future soft armour standards and provide important quantitative data for numerical model correlation and development. The implications of the findings of the work on the reliability and repeatability of the industry standard V50 ballistic test are also discussed

    Breeding \u3cem\u3eLotus Australis\u3c/em\u3e Andrews for Low Cyanide Content

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    Lotus australis Andrews is a native perennial tetraploid legume (2n=4x=28) widely distributed throughout Australia (Figure 1). It is highly variable with 14 botanical varieties reported in the Australian Plant Name Index (http://www.anbg.gov.au). Despite broad adaptation within L. australis no cultivars have been developed for cultivation. One of the main barriers to cultivation is the reported cyanogenic nature of the species (Foulds, 1982), which makes it potentially toxic when plant cyanogenic glycosides are fully hydrolysed to form hydrogen cyanide (HCN). Foulds (1982) also reported that the cyanophoric trait was polymorphic at seedling and adult stages with 12% of plants acyanogenic in some populations. . The Cooperative Research Center for Plant-Based Management of Dryland Salinity, financially supported by Australian Wool Innovation has commenced a breeding program to develop a non-toxic cultivar of L. australis. The selection criterion of the first phase of the breeding programme was for low HCN production. Once this trait is stabilised, forage production and seed yield as well as general plant health will be the main breeding objectives

    Weapon-wound matching of sharp force trauma to bone – a micro-CT analysis

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    Nearly 40% of murders in the UK result from sharp force trauma caused by knives. Weapon-wound matching in Forensic anthropology attempts to estimate weapon class from the wound characteristics but few studies have investigated quantitative methods for performing this analysis on the microscopic scale. In this study five cadaveric pig torsos, prepared to mimic human anatomy, were stabbed in the upright position with 12 different knives. Knife dynamics were recorded using a Casio high-speed camera (420fps). Samples were chemically defleshed exposing the regions on the ribs where the knives have made contact, thus marking the bone, so micro-CT can be performed. All samples underwent a pre and post-stab CT scan so that rib marks could be matched to the knife used. Preliminary results show that there is a significant difference between serrated and none serrated cut geometry regardless of knife force or penetration angle. If these results hold true for the larger sample of knives tested within this study (analysis currently in progress) and the significant differences between knives are above noise then, a new technique for statistically estimating knife class from cut marks can be developed. Applications of this in forensic anthropology will aid criminal investigators in their inquiries

    The structure of the hexameric atrazine chlorohydrolase AtzA

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    Atrazine chlorohydrolase (AtzA) was discovered and purified in the early 1990s from soil that had been exposed to the widely used herbicide atrazine. It was subsequently found that this enzyme catalyzes the first and necessary step in the breakdown of atrazine by the soil organism Pseudomonas sp. strain ADP. Although it has taken 20 years, a crystal structure of the full hexameric form of AtzA has now been obtained. AtzA is less well adapted to its physiological role (i.e. atrazine dechlorination) than the alternative metal-dependent atrazine chlorohydrolase (TrzN), with a substrate-binding pocket that is under considerable strain and for which the substrate is a poor fit

    Relationships between Peak Oxygen Uptake and Arterial Function: a Preliminary Study

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    Please view abstract in the attached PDF file

    Re-engineering forensic anthropology : new techniques in sharp force trauma analysis

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    In forensic anthropology the analysis of microscopic tool marks found in skeletal sharp force trauma is a challenging area. Many different imaging methods have been employed to measure cut mark characteristics in aid of developing diagnostic tools for estimating knife type used for these marks. Furthermore numerous experimental methods for creating tool marks for analysis have been used. A novel method for creating, analysing and presenting tool marks using reverse engineering and metrology was investigated. 5 Pig torsos prepared to mimic human anatomy were stabbed using seven different knives. Following chemical defleshing the ribs were micro-CT scanned for the analysis of tool marks left from the knives. Other methods including SEM, Digital microscopy and Laser scanning were also considered. Various geometrical measurements of the cut mark micro-morphology were taken. These measurements were statistically analysed using SPSS. Knife types gave statistically significant different cut mark width, length, wall angle, floor radius and shape (p<0.001). Knife sub-types and individual knives also gave statistically significant differencing in width and shape (p<0.001). Statistical classification of cut marks as either serrated or non-serrated made marks was shown to be 90% if width, length, wall angle and floor radius were accounted for. This indicated that determining knife type quantitatively is possible and could aid criminal investigators with their enquires. 3D models of these cut marks could also be developed for potential use in court for forensic expert testimony

    Serum 25-Hydroxyvitamin D and Intact Parathyroid Hormone Influence Muscle Outcomes in Children and Adolescents

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    Increases in 25-hydroxyvitamin D concentrations are shown to improve strength in adults; however, data in pediatric populations are scant and equivocal. In this ancillary study of a larger-scale, multi-sited, double-blind, randomized, placebo-controlled vitamin D intervention in US children and adolescents, we examined the associations between changes in vitamin D metabolites and changes in muscle mass, strength, and composition after 12 weeks of vitamin D3 supplementation. Healthy male and female, black and white children and adolescents between the ages of 9 and 13 years from two US states (Georgia 34°N and Indiana 40°N) were enrolled in the study and randomly assigned to receive an oral vitamin D3 dose of 0, 400, 1000, 2000, or 4000 IU/d for 12 weeks between the winter months of 2009 to 2011 (N = 324). Analyses of covariance, partial correlations, and regression analyses of baseline and 12-week changes (post-baseline) in vitamin D metabolites (serum 25(OH)D, 1,25(OH)2 D, intact parathyroid hormone [iPTH]), and outcomes of muscle mass, strength, and composition (total body fat-free soft tissue [FFST], handgrip strength, forearm and calf muscle cross-sectional area [MCSA], muscle density, and intermuscular adipose tissue [IMAT]) were assessed. Serum 25(OH)D and 1,25(OH)2 D, but not iPTH, increased over time, as did fat mass, FFST, forearm and calf MCSA, forearm IMAT, and handgrip strength (p < 0.05). Vitamin D metabolites were not associated with muscle strength at baseline nor after the 12-week intervention. Changes in serum 25(OH)D correlated with decreases in forearm IMAT, whereas changes in serum iPTH predicted increases in forearm and calf MCSA and IMAT (p < 0.05). Overall, increases in 25(OH)D did not influence muscle mass or strength in vitamin D-sufficient children and adolescents; however, the role of iPTH on muscle composition in this population is unknown and warrants further investigation

    Topical Nutrients Promote Engraftment and Inhibit Wound Contraction of Cultured Skin Substitutes in Athymic Mice

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    Routine treatment of burns with cultured skin substitutes (CSS) has been limited by poor engraftment and by scarring. Hypothetically, topical application of essential nutrients and/or growth factors may support epithelial survival temporarily during graft vascularization, CSS, composed of human epidermal keratinocytes and dermal fibroblasts attached to collagen-glycosaminoglycan substrates, were incubated for 19 d in media optimized for keratinocytes. CSS, human xenografts, murine autografts, or no grafts were applied orthotopically to full-thickness skin wounds (2 × 2 cm) in athymic mice. Wounds were irrigated for 14 d with 1 ml/d modified cell culture medium or with saline containing epidermal growth factor, or were treated with dry dressings. After 6 weeks, treated sites were scored for percentage original wound area (mean ± SEM) and percentage HLA- ABC-positive healed wounds [(number positive/n) × 100], and tested for significance (analysis of variance, p < 0.0001; Tukey test, p < 0.05). The data showed that CSS irrigated with nutrient medium were not statistically different in wound area (67.8 ± 5.1%) from murine autografts (63.3 ± 2.9%) but were statistically larger than human xenograft, no graft, or CSS treated with saline irrigation or dry dressings. HLA- ABC expression was 100% in CSS with nutrient irrigation, 86% in CSS with saline irrigation, 83% In CSS without irrigation, and 75% in xenografts with nutrient irrigation. These findings suggest that availability of essential nutrients supports keratinocyte viability during graft vascularization of CSS

    The vulnerability of public spaces: challenges for UK hospitals under the 'new' terrorist threat

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    This article considers the challenges for hospitals in the United Kingdom that arise from the threats of mass-casualty terrorism. Whilst much has been written about the role of health care as a rescuer in terrorist attacks and other mass-casualty crises, little has been written about health care as a victim within a mass-emergency setting. Yet, health care is a key component of any nation's contingency planning and an erosion of its capabilities would have a significant impact on the generation of a wider crisis following a mass-casualty event. This article seeks to highlight the nature of the challenges facing elements of UK health care, with a focus on hospitals both as essential contingency responders under the United Kingdom's civil contingencies legislation and as potential victims of terrorism. It seeks to explore the potential gaps that exist between the task demands facing hospitals and the vulnerabilities that exist within them
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