444 research outputs found
The visceral response to underbody blast
Blast is the most common cause of injury and death in contemporary warfare. Blast
injuries may be categorised based upon their mechanism with underbody blast
describing the effect of an explosive device detonating underneath a vehicle. Torso
injuries are highly lethal within this environment and yet their mechanism in response
to underbody blast is poorly understood. This work seeks to understand the pattern and
mechanism of these injuries and to link them to physical underbody blast loading
parameters in order to enable mitigation and prevention of serious injury and death.
An analysis of the United Kingdom Joint Theatre Trauma Registry for underbody blast
events demonstrates that torso injury is a major cause of morbidity and mortality from
such incidents. Mediastinal injury, including those trauma to the heart and thoracic great
vessels is shown confer the greatest lethality within this complex environment.
This work explores the need for a novel in vivo model of underbody loading in order to
explore the mechanisms of severe torso injury and to define the relationship between
the âdoseâ of underbody loading and resultant injury. The work includes the
development of a new rig which causes underbody blast analogous vertical accelerations
upon a seated rat model.
Injuries causes by this loading to both the chest and abdomen can be best predicted by
the examining the kinematic response of the torso to the loading. Axial compression of
the torso, a previously undescribed injury metric is shown to be the best predictor of
injury. The ability of these results to translate to a human model is explored in detail,
with focus upon the biomechanical rationale; that torso organ injuries occur through
both direct compression and shearing of tethering attachments.
Survivability of underbody blast could be improved by applying these principles to the
design and modification of seats, vehicles and posture.Open Acces
Self-directed learning and apprentices: a constructivist grounded study
Developing the capacity of learners to be self-directed is beneficial for both individual workers and economies alike. This study investigates the development of capability for self-directed learning in a group of apprentices in the building and construction industry and suggests that such capability is best developed in the early years of entry
into the workforce. For tradespersons this time is during their apprenticeship.
The purpose of this study was to develop a deep understanding of how apprentices develop the capacity to be self-directed learners. The aim was to develop a substantive
theory that illuminated and provided insight into this phenomenon.
The methodology of constructivist grounded theory was used to conduct the study. A sample size of 13 participants in the building and construction industry was recruited.
This included apprentices who were employed by a group training organisation (GTO) and a representation of their host employers and vocational teachers located within the
southern New South Wales and the Australian Capital Territory geographic regions.
The substantive theory presented in this dissertation makes a contribution to knowledge of value to apprentices, employers, vocational teachers and others who seek to develop an understanding of the process of learning and development associated with apprenticeships and vocational and professional education more broadly.
The substantive theory was achieved through discovering, describing, analyzing abstracting and explaining how apprentices moved through the phases (or categories) of committing effort, experiencing work, confirming value, and heightening motivation towards becoming self-directed learners. The substantive theory reveals that as the
apprentices progressed through these phases they were constantly engaged in decision making processes, evaluating and re-evaluating experiences throughout their
apprenticeship. The evaluation outcomes could be positive or negative and were dependent upon the expectancies that the apprentices placed on themselves as well as their interpretation of the expectancies placed on them by others.
In this study the manner in which the various conceptual elements, processes and categories connect revolves around the apprenticesâ experiences of sponsorship. Sponsorship is the term used to describe the more experienced or confident other who has both a personal and professional interest in the apprenticeâs development and uses their influence to create a safe learning environment to enable the apprentice to develop expertise.
The importance of the management of the learning environment proved critical, as suitable learning contexts do not appear by accident. In this study it emerged that the
sponsor was the most important factor determining the quality of the learning environment. Effective sponsors were able to manage the learning context in a manner
where the apprentice felt safe to ask questions, make mistakes, develop expertise and eventually accept responsibility, be autonomous and solve complex problems. Indeed, the apprentices became tradespeople who were not only competent but were true self directed learners.
By managing this learning context, the sponsor created an environment that enabled the intrinsic motivation of the apprentice to drive their own growth and development
towards becoming self-directed learners. When the sponsor creates a workplace where learning thrives, the apprentice begins to develop both competence and confidence.
Increasingly, the apprentice begins to consolidate a durable sense of vocational identity. More and more others (both within and outside the immediate workplace)begin to recognise the apprentice as a legitimate member of the trade. Over time, with the development of expertiseâas the apprentice begins to accept more and more responsibility for their own learning, and with encouragement and opportunity from the sponsorâthey begin to reflect on their own learning. Increasingly and steadily they become self-directed learners
A review of knowledge of the potential impacts of GMOs on organic agriculture
The organic movement believes that organic agriculture, by its nature, cannot involve the use of genetically modified organisms (GMOs). This has been incorporated into EU regulations which state that there is no place in organic agriculture for GMOs. The aim in this review is to consider the ways in which the use of GMOs in agriculture in the UK and internationally might impact on organic farming. It does not address the controversy about the rights or wrongs of GMOâs per se. The subjects covered are based on a set of questions raised at the beginning of the study. The review is based primarily on evidence from peer-reviewed literature.
The report is based on a number of themes, as follows:
⢠Fate of DNA in soil
⢠Fate of DNA in livestock feed and possible impact of GM feed
⢠Fate of DNA in slurry, manure, compost and mulch
⢠Impact of herbicide tolerant crops
⢠Impact of pest and disease resistant crops
⢠Safety of promoters
⢠DNA transfer in pollen and seeds
⢠Horizontal gene transfer
⢠Impact of scale
The reportâs Executive Summary includes summaries of the findings on each of these themes
A diagnostic autoantibody signature for primary cutaneous melanoma
Melanoma is an aggressive form of skin cancer that is curable by surgical excision in the majority of cases, if detected at an early stage. To improve early stage melanoma detection, the development of a highly sensitive diagnostic test is of utmost importance. Here we aimed to identify antibodies to a panel of tumour associated antigens that can differentiate primary melanoma patients and healthy individuals. A total of 245 sera from primary melanoma patients and healthy volunteers were screened against a high-throughput microarray platform containing 1627 functional proteins. Following rigorous statistical analysis, we identified a combination of 10 autoantibody biomarkers that, as a panel, displays a sensitivity of 79%, specificity of 84% and an AUC of 0.828 for primary melanoma detection. This melanoma autoantibody signature may prove valuable for the development of a diagnostic blood test for routine population screening that, when used in conjunction with current melanoma diagnostic techniques, could improve the early diagnosis of this malignancy and ultimately decrease the mortality rate of patients
Carbon dioxide and ocean acidification observations in UK waters. Synthesis report with a focus on 2010â2015
Key messages: 1.1 The process of ocean acidification is now relatively well-documented at the global scale as a long-term trend in the open ocean. However, short-term and spatial variability can be high. 1.2 New datasets made available since Charting Progress 2 make it possible to greatly improve the characterisation of CO2 and ocean acidification in UK waters. 3.1 Recent UK cruise data contribute to large gaps in national and global datasets. 3.2 The new UK measurements confirm that pH is highly variable, therefore it is important to measure consistently to determine any long term trends. 3.3 Over the past 30 years, North Sea pH has decreased at 0.0035Âą0.0014 pH units per year. 3.4 Upper ocean pH values are highest in spring, lowest in autumn. These changes reflect the seasonal cycles in photosynthesis, respiration (decomposition) and water mixing. 3.5 Carbonate saturation states are minimal in the winter, and lower in 7 more northerly, colder waters. This temperature-dependence could have implications for future warming of the seas. 3.6 Over the annual cycle, North-west European seas are net sinks of CO2. However, during late summer to autumn months, some coastal waters may be significant sources. 3.7 In seasonally-stratified waters, sea-floor organisms naturally experience lower pH and saturation states; they may therefore be more vulnerable to threshold changes. 3.8 Large pH changes (0.5 - 1.0 units) can occur in the top 1 cm of sediment; however, such effects are not well-documented. 3.9 A coupled forecast model estimates the decrease in pH trend within the North Sea to be -0.0036Âą0.00034 pH units per year, under a high greenhouse gas emissions scenario (RCP 8.5). 3.10 Seasonal estimates from the forecast model demonstrate areas of the North Sea that are particularly vulnerable to aragonite undersaturation
Associations between comorbid anxiety and sleep disturbance in people with bipolar disorder: Findings from actigraphy and subjective sleep measures
Background
Studies show that comorbid anxiety disorders are common in people with bipolar disorder. However, little is known about whether this anxiety is associated with sleep disturbance. We investigated, in individuals with bipolar disorder, whether comorbid anxiety disorder is associated with sleep disturbance.
Methods
Participants were 101 (64% female) currently euthymic individuals with a history of bipolar disorder. Sleep disturbances were assessed using self-report measures of sleep quality (Pittsburgh Sleep Quality Index, PSQI) and six weeks of sleep monitoring using actigraphy. Bipolar disorder and comorbid anxiety diagnoses were assessed using the Mini International Neuropsychiatric Interview. Multiple regression analyses examined associations between comorbid anxiety and sleep disturbance, whilst controlling for confounding covariates known to impact on sleep.
Results
A comorbid anxiety disorder was associated with increased sleep disturbance as measured using the PSQI global score (BâŻ=âŻ3.58, 95% CI 1.85â5.32, PâŻ<âŻ0.001) but was not associated with sleep metrics (total sleep time, sleep onset latency, sleep efficiency, and wake after sleep onset) derived using actigraphy.
Limitations
Objective measures of sleep were limited to actigraphy, therefore we were not able to examine differences in sleep neurophysiology.
Conclusions
Clinicians should be aware that comorbid anxiety may increase the risk of experiencing subjective sleep disturbance in people with bipolar disorder. Research should assess for evidence of comorbid anxiety when examining associations between sleep and bipolar disorder. Future research should explore the mechanisms by which comorbid anxiety may contribute to subjective sleep disturbances in bipolar disorder using neurophysiological measures of sleep (i.e., polysomnography)
Novel composite organic-inorganic semiconductor sensors for the quantitative detection of target organic vapours
Composites of tin dioxide (an n-type semiconductor) and derivatives of the conducting polymer polypyrrole (a p-type semiconductor) gave reversible changes in electrical resistance at room temperature when exposed to a range of organic vapours. The optimum amount of polymer giving highest sensitivity was found by experiment to be 2.5% by mass for the polypyrrole chloride-tin dioxide composite. Composites containing 2.5% polymer by mass, but differing in polymer derivative, were fabricated and exposed to low concentrations of ethanol, methanol, acetone, methyl acetate and ethyl acetate. All were found to give significant and reversible decreases in electrical resistance. Direct comparison with sensors constructed solely of tin dioxide or polypyrrole at room temperature showed the composites to be more sensitive. The gas sensitivity of the composite materials depended on the type of polymer derivative incorporated and the dopant anion associated with the polymer. The composites were simple to fabricate and gave differing response profiles to a range of organic vapours
The age, origin and emplacement of the Tsiknias Ophiolite, Tinos, Greece
The Tsiknias Ophiolite, exposed at the highest structural levels of Tinos, Greece, represents a thrust sheet of Tethyan oceanic crust and upper mantle emplaced onto the AtticâCycladic Massif. We present new field observations and a new geological map of Tinos, integrated with petrology, THERMOCALC phase diagram modelling, UâPb geochronology and whole rock geochemistry, resulting in a tectonoâthermal model that describes the formation and emplacement of the Tsiknias Ophiolite and newly identified underlying metamorphic sole. The ophiolite comprises a succession of partially dismembered and structurally repeated ultramafic and gabbroic rocks that represent the Moho Transition Zone. A plagiogranite dated by UâPb zircon at 161.9 Âą 2.8 Ma, reveals that the Tsiknias Ophiolite formed in a supraâsubduction zone setting, comparable to the âEastâVardar Ophiolitesâ, and was intruded by gabbros at 144.4 Âą 5.6 Ma. Strongly sheared metamorphic sole rocks show a condensed and inverted metamorphic gradient, from partially anatectic amphibolites at PâT conditions of ca. 8.5 kbar 850â600 °C, downâstructural section to greenschistâfacies oceanic metasediments over ~250 m. Leucosomes generated by partial melting of the uppermost sole amphibolite, yielded a UâPb zircon protolith age of ca. 190 Ma and a highâgrade metamorphicâanatectic age of 74.0 Âą 3.5 Ma associated with ophiolite emplacement. The Tsiknias Ophiolite was therefore obducted ~90 Myrs after it formed during initiation of a NEâdipping intraâoceanic subduction zone to the northeast of the Cyclades that coincides with Africa's plate motion changing from transcurrent to convergent. Continued subduction resulted in highâpressure metamorphism of the Cycladic continental margin ~25 Myrs later
XIPE: the X-ray Imaging Polarimetry Explorer
X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and
temporal variability measurements and to imaging, allows a wealth of physical
phenomena in astrophysics to be studied. X-ray polarimetry investigates the
acceleration process, for example, including those typical of magnetic
reconnection in solar flares, but also emission in the strong magnetic fields
of neutron stars and white dwarfs. It detects scattering in asymmetric
structures such as accretion disks and columns, and in the so-called molecular
torus and ionization cones. In addition, it allows fundamental physics in
regimes of gravity and of magnetic field intensity not accessible to
experiments on the Earth to be probed. Finally, models that describe
fundamental interactions (e.g. quantum gravity and the extension of the
Standard Model) can be tested. We describe in this paper the X-ray Imaging
Polarimetry Explorer (XIPE), proposed in June 2012 to the first ESA call for a
small mission with a launch in 2017 but not selected. XIPE is composed of two
out of the three existing JET-X telescopes with two Gas Pixel Detectors (GPD)
filled with a He-DME mixture at their focus and two additional GPDs filled with
pressurized Ar-DME facing the sun. The Minimum Detectable Polarization is 14 %
at 1 mCrab in 10E5 s (2-10 keV) and 0.6 % for an X10 class flare. The Half
Energy Width, measured at PANTER X-ray test facility (MPE, Germany) with JET-X
optics is 24 arcsec. XIPE takes advantage of a low-earth equatorial orbit with
Malindi as down-link station and of a Mission Operation Center (MOC) at INPE
(Brazil).Comment: 49 pages, 14 figures, 6 tables. Paper published in Experimental
Astronomy http://link.springer.com/journal/1068
Biophysical basis of filamentous phage tactoid-mediated antibiotic tolerance in P. aeruginosa
Inoviruses are filamentous phages infecting numerous prokaryotic phyla. Inoviruses can self-assemble into mesoscale structures with liquid-crystalline order, termed tactoids, which protect bacterial cells in Pseudomonas aeruginosa biofilms from antibiotics. Here, we investigate the structural, biophysical, and protective properties of tactoids formed by the P. aeruginosa phage Pf4 and Escherichia coli phage fd. A cryo-EM structure of the capsid from fd revealed distinct biochemical properties compared to Pf4. Fd and Pf4 formed tactoids with different morphologies that arise from differing phage geometries and packing densities, which in turn gave rise to different tactoid emergent properties. Finally, we showed that tactoids formed by either phage protect rod-shaped bacteria from antibiotic treatment, and that direct association with a tactoid is required for protection, demonstrating the formation of a diffusion barrier by the tactoid. This study provides insights into how filamentous molecules protect bacteria from extraneous substances in biofilms and in host-associated infections
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