Application of photon Doppler velocimetry to direct impact Hopkinson pressure bars.

Direct impact Hopkinson pressure bar systems offer many potential advantages over split Hopkinson pressure bars, including access to higher strain rates, higher strains for equivalent striker velocity and system length, lower dispersion, and faster achievement of force equilibrium. Currently, these advantages are gained at the expense of all information about the striker impacted specimen face, preventing the experimental determination of force equilibrium, and requiring approximations to be made on the sample deformation history. In this paper, we discuss an experimental method and complementary data analysis for using photon Doppler velocimetry to measure surface velocities of the striker and output bars in a direct impact bar experiment, allowing similar data to be recorded as in a split bar system. We discuss extracting velocity and force measurements, and the precision of measurements. Results obtained using the technique are compared to equivalent split bar tests, showing improved stress measurements for the lowest and highest strains in fully dense metals, and improvement for all strains in slow and non-equilibrating materials.This research was supported by grants from QinetiQ and the Engineering and Physical Sciences Research Council.This is the author accepted manuscript. The final version is available from AIP Publishing via http://dx.doi.org/10.1063/1.494093

Life-long learning in laboratory animal science and ethics for veterinary and para-veterinary professionals in South Africa

Veterinary and para-veterinary professionals working in the animal research sector are critical to ensure scientific quality and the humane care and use of animals. However, there are few focused education and training opportunities available for these professionals in South Africa. A survey of veterinarians working in animal research, undertaken by the South African Association for Laboratory Animal Science, identified the need for more advanced education and training opportunities beyond the routine Day 1 Skills currently provided for in undergraduate education. These could be broadly categorised into knowledge and skills relating to species-specific husbandry, procedures and clinical approaches, research-related biosecurity and biosafety, and study-specific ethical and animal welfare considerations. A subsequent workshop, attended by 85 veterinary and para-veterinary professionals in the animal research sector, identified 53 life-long learning needs, each with an associated learning outcome, for this professional community. These were grouped into five overarching themes: Personal development (9); Leadership and management skills (12); Education and training skills (5); Welfare, ethics and clinical skills (20); and Regulations and quality-assurance (7). Of the 53 learning outcomes, 14 were knowledge-based, ten were competencies, and 29 both knowledge and competence. These life-long learning opportunities, if available and implemented, will address important needs of veterinary and paraveterinary professionals in the animal research sector in South Africa. This would empower these professionals, assist in improving animal and human wellbeing, support high-quality ethical science, and maintain public confidence in the sector, thus enabling a more satisfactory career environment

Prolonged post-faint hypotension can be reversed by dynamic tension

A severe variant of vasovagal syncope, observed during tilt tests and blood donation has recently been termed “prolonged post-faint hypotension” (PPFH). A 49-year-old male with a life-long history of severe fainting attacks underwent head-up tilt for 20 min, and developed syncope 2 min after nitroglycerine spray. He was unconscious for 40 s and asystolic for 22 s. For the first 2 min of recovery, BP and HR remained low (65/45 mmHg and 40 beats/min) despite passive leg-raising. Blood pressure (and symptoms) only improved following active bilateral leg flexion and extension (“dynamic tension”). During PPFH, when vagal activity is extreme, patients may require central stimulation as well as correction of venous return

Are you Ready? Assessing Whether Organisations are Prepared for Digital Preservation

In early 2009 the Planets project undertook a survey of national libraries, archives, and other content-holding organisations in Europe to better understand the organisations' digital preservation activities and needs, and to ensure that Planets' technology and services are designed to meet them. Over 200 responses were received including a cross-section of major libraries and archives especially in Europe. The results provide a snapshot of organisations' readiness to preserve digital collections for the future. The survey revealed a high level of awareness of the challenges of digital preservation within organisations. Findings indicated that approximately half of those organisations surveyed have taken measures to develop digital preservation policies and to budget for it, while a majority have incorporated digital preservation into their organisational planning. Organisations predict that within a decade they will need to store large quantities of data in a wide range of formats from a variety of sources; three quarters of them are looking to invest in a solution within the next two years. However, the findings also point to varying degrees of readiness. Organisations with a digital preservation policy are significantly further advanced in their work to preserve digital collections for the long-term than others

The modern pollen-vegetation relationship of a tropical forest-savannah mosaic landscape, Ghana, West Africa

Transitions between forest and savannah vegetation types in fossil pollen records are often poorly understood due to over-production by taxa such as Poaceae and a lack of modern pollen-vegetation studies. Here, modern pollen assemblages from within a forest-savannah transition in West Africa are presented and compared, their characteristic taxa discussed, and implications for the fossil record considered. Fifteen artificial pollen traps were deployed for 1 year, to collect pollen rain from three vegetation plots within the forest-savannah transition in Ghana. High percentages of Poaceae and Melastomataceae/Combretaceae were recorded in all three plots. Erythrophleum suaveolens characterised the forest plot, Manilkara obovata the transition plot and Terminalia the savannah plot. The results indicate that Poaceae pollen influx rates provide the best representation of the forest-savannah gradient, and that a Poaceae abundance of >40% should be considered as indicative of savannah-type vegetation in the fossil record

On the semantics of fuzzy logic

AbstractThis paper presents a formal characterization of the major concepts and constructs of fuzzy logic in terms of notions of distance, closeness, and similarity between pairs of possible worlds. The formalism is a direct extension (by recognition of multiple degrees of accessibility, conceivability, or reachability) of the najor modal logic concepts of possible and necessary truth.Given a function that maps pairs of possible worlds into a number between 0 and 1, generalizing the conventional concept of an equivalence relation, the major constructs of fuzzy logic (conditional and unconditioned possibility distributions) are defined in terms of this similarity relation using familiar concepts from the mathematical theory of metric spaces. This interpretation is different in nature and character from the typical, chance-oriented, meanings associated with probabilistic concepts, which are grounded on the mathematical notion of set measure. The similarity structure defines a topological notion of continuity in the space of possible worlds (and in that of its subsets, i.e., propositions) that allows a form of logical “extrapolation” between possible worlds.This logical extrapolation operation corresponds to the major deductive rule of fuzzy logic — the compositional rule of inference or generalized modus ponens of Zadeh — an inferential operation that generalizes its classical counterpart by virtue of its ability to be utilized when propositions representing available evidence match only approximately the antecedents of conditional propositions. The relations between the similarity-based interpretation of the role of conditional possibility distributions and the approximate inferential procedures of Baldwin are also discussed.A straightforward extension of the theory to the case where the similarity scale is symbolic rather than numeric is described. The problem of generating similarity functions from a given set of possibility distributions, with the latter interpreted as defining a number of (graded) discernibility relations and the former as the result of combining them into a joint measure of distinguishability between possible worlds, is briefly discussed

Lack of effect of lowering LDL cholesterol on cancer: meta-analysis of individual data from 175,000 people in 27 randomised trials of statin therapy

<p>Background: Statin therapy reduces the risk of occlusive vascular events, but uncertainty remains about potential effects on cancer. We sought to provide a detailed assessment of any effects on cancer of lowering LDL cholesterol (LDL-C) with a statin using individual patient records from 175,000 patients in 27 large-scale statin trials.</p> <p>Methods and Findings: Individual records of 134,537 participants in 22 randomised trials of statin versus control (median duration 4.8 years) and 39,612 participants in 5 trials of more intensive versus less intensive statin therapy (median duration 5.1 years) were obtained. Reducing LDL-C with a statin for about 5 years had no effect on newly diagnosed cancer or on death from such cancers in either the trials of statin versus control (cancer incidence: 3755 [1.4% per year [py]] versus 3738 [1.4% py], RR 1.00 [95% CI 0.96-1.05]; cancer mortality: 1365 [0.5% py] versus 1358 [0.5% py], RR 1.00 [95% CI 0.93–1.08]) or in the trials of more versus less statin (cancer incidence: 1466 [1.6% py] vs 1472 [1.6% py], RR 1.00 [95% CI 0.93–1.07]; cancer mortality: 447 [0.5% py] versus 481 [0.5% py], RR 0.93 [95% CI 0.82–1.06]). Moreover, there was no evidence of any effect of reducing LDL-C with statin therapy on cancer incidence or mortality at any of 23 individual categories of sites, with increasing years of treatment, for any individual statin, or in any given subgroup. In particular, among individuals with low baseline LDL-C (<2 mmol/L), there was no evidence that further LDL-C reduction (from about 1.7 to 1.3 mmol/L) increased cancer risk (381 [1.6% py] versus 408 [1.7% py]; RR 0.92 [99% CI 0.76–1.10]).</p> <p>Conclusions: In 27 randomised trials, a median of five years of statin therapy had no effect on the incidence of, or mortality from, any type of cancer (or the aggregate of all cancer).</p&gt

The Relationship between Proteinuria and Coronary Risk: A Systematic Review and Meta-Analysis

Vlado Perkovic and colleagues show, through a systematic review and meta-analysis of cohort studies, that there is a strong and continuous association between proteinuria and subsequent risk of coronary heart disease

Domesticating Fears and Fantasies of ‘the East’: integrating the Ottoman legacy within European heritage

'Europe' has no fixed geographical, historical, religious or cultural boundaries. Claims for the existence of European civilization as a discrete construct are continually made yet dissolve on close scrutiny. Here, we examine these claims at one of the grandest points of existential crisis and belonging for Europe, the relationship with the 'Other within': Turkey, the Balkans and Ottoman heritage in Europe. Through a hybrid semiotic and Foucauldian analysis of catalogues of eight high-profile exhibitions in the United Kingdom, Turkey, Belgium and Portugal we argue that an unsettled discursive struggle is at play, in which one 'Europe' articulates 'reconciliation' of profound civilizational difference while another, Ottoman, 'Europe' stakes a claim of right as an intrinsic component of what it means to be European in a contemporary context. We attempt to trace the role of museum marketing in the perennial accommodation/exclusion of the Ottoman Empire as an intrinsic component in the diversity of Europe’s cultural heritage

Shorebirds affect ecosystem functioning on an intertidal mudflat

Ecosystem functioning and services have provided a rationale for conservation over the past decades. Intertidal muddy sediments, and the microphytobenthic biofilms that inhabit them, perform crucial ecosystem functions including erosion protection, nutrient cycling and carbon sequestration. It has been suggested that predation on sediment macrofauna by shorebirds may impact biofilms, and shorebirds are known to consume biofilm, potentially causing significant top-down effects on mudflat ecosystem functioning. We carried out an exclusion experiment on the Colne Estuary, Essex, UK to examine whether shorebird presence significantly affects sediment erodibility measured with a Cohesive Strength Meter (CSM) and microphytobenthos biomass measured using PAM fluorescence (Fo) and chlorophyll a content. We also tested for treatment effects on sediment-water nutrient fluxes (nitrate, nitrite, ammonia, phosphate and dissolved organic carbon (DOC)) during periods of both dark and light incubation. Excluding shorebirds caused statistically significant changes in regulating and provisioning ecosystem functions, including mudflat erodibility and nutrient fluxes. The presence of shorebirds lowered the sediment critical erosion threshold, reduced nitrate fluxes into the sediment under illumination, lowered nitrate efflux, and reduced phosphate uptake, compared to sediments where birds were excluded. There were no significant differences in macrofauna community composition within the sediment between treatments after 45 days of bird exclusion, suggesting a direct link between shorebird presence or absence and the significant differences in biofilm-related variables. This study introduces previously unknown effects of shorebird presence on ecosystem functions within this system and highlights an area of shorebird science that could aid joint conservation and human provisioning action