1,096 research outputs found
Maternal and cohort effects modulate offspring responses to multiple stressors
Current concerns about climate change have led to intensive research attempting to understand how climate driven stressors affect the performance of organisms, in particular on offspring of many invertebrates and fish. Although stressors are likely to act on several stages of the life cycle, little is known about their action across life phases, for instance how multiple stressors experienced simultaneously in the maternal environment can modulate the responses to the same stressors operating in the offspring environment. Here, we study how performance of offspring of a marine invertebrate (shore crab Carcinus maenas) in response to two stressors (temperature and salinity) changes if the same stressors are experienced at the time of embryogenesis in cohorts of mothers brooding eggs at different seasons. On average, offspring responses were antagonistic: high temperature mitigated the negative effects of low salinity on survival. However, the magnitude of the response was modulated by the temperature and salinity conditions experienced by egg-carrying mothers. Performance also varied among cohorts, perhaps reflecting genetic variation, and/or maternal conditions prior to embryogenesis. This study contributes towards the understanding of how anthropogenic modification of the maternal environment drives offspring performance in brooders
Pebble bed: reflector treatment and pressure\ud velocity coupling
In this report, we describe some models and numerical methods used to simulate the flow and temperature in a pebble bed modular nuclear reactor. The reactor core is filled with around 450000 spheres containing low enriched uranium and helium is forced through these hot pebbles to cool the system down. The group first investigated the flow model in the pebbles. Numerical aspects were then considered to tackle difficulties encountered with the flow simulation and the temperature inside the pebbles. Numerical schemes are presented that can significantly improve the accuracy of the computed results
Political brand identity: an examination of the complexities of Conservative brand and internal market engagement during the 2010 UK General Election campaign
This paper seeks to build an understanding of the importance of internal communications when building a strong political brand. Using Kapfererâs brand prism as a conceptual framework, the paper explores UK Conservative Party membersâ attitudes towards the development of the Conservative brand as personified by David Cameron. There are clear implications for political strategists as the findings suggest that it is crucial to engage the internal market in the co-creation of the marketing communications strategy for as brand evangelists they interpret the brand promise at the local level
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Effects of antiplatelet therapy after stroke due to intracerebral haemorrhage (RESTART): a randomised, open-label trial
Antiplatelet therapy reduces the risk of major vascular events for people with occlusive vascular disease, although it might increase the risk of intracranial haemorrhage. Patients surviving the commonest subtype of intracranial haemorrhage, intracerebral haemorrhage, are at risk of both haemorrhagic and occlusive vascular events, but whether antiplatelet therapy can be used safely is unclear. We aimed to estimate the relative and absolute effects of antiplatelet therapy on recurrent intracerebral haemorrhage and whether this risk might exceed any reduction of occlusive vascular events
Party activism in the populist radical right: The case of the UK Independence Party
Recent decades have seen an upsurge of interest in populist radical right (PRR) parties. Yet despite a large body of research on PRR voters, there are few studies of the internal life of these parties. In particular, there is a dearth of research about why people are active in them. This article uses data from a unique large-scale survey of United Kingdom Independence Party (UKIP) members to investigate if drivers of voting support for these parties are also important for explaining party activism. Analyses show that traditional models of party activism are important for understanding engagement in UKIP, but macro-level forces captured in an expanded relative deprivation model also stimulate participation in the party. That said macro-level forces are not the dominant driver of activism
Clinical Diagnosis and Magnetic Resonance Imaging in Patients With Transient and Minor Neurological Symptoms: A Prospective Cohort Study
The utility of magnetic resonance imaging (MRI) brain in patients with transient or minor neurological symptoms is uncertain. We sought to determine the proportion of participants with transient or minor neurological symptoms who had MRI evidence of acute ischemia at different clinical probabilities of transient ischemic attack (TIA) or minor stroke. METHODS: Cohort of participants with transient or minor neurological symptoms from emergency and outpatient settings. Clinicians at different levels of training gave each participant a diagnostic probability (probable when TIA/stroke was the most likely differential diagnosis; possible when TIA/stroke was not the most likely differential diagnosis; or uncertain when diagnostic probability could not be given) before 1.5 or 3T brain MRI â€5 days from onset. Post hoc, each clinical syndrome was defined blind to MRI findings as National Institute of Neurological Disorders and Stroke criteria TIA/stroke; International Headache Society criteria migraine aura; non-TIA focal symptoms; or nonfocal symptoms. MRI evidence of acute ischemia was defined by 2 reads of MRI. Stroke was ascertained for at least 90 days and up to 18 months after recruitment. RESULTS: Two hundred seventy-two participated (47% female, mean age 60, SD 14), 58% with MRI â€2 days of onset. Most (92%) reported focal symptoms. MR evidence of acute ischemia was found, for stroke/TIA clinical probabilities of probable 23 out of 75 (31% [95% CI, 21%â42%]); possible 26 out of 151 (17% [12%â24%]); and uncertain 9 out of 43, (20% [10%â36%]). MRI evidence of acute ischemia was found in National Institute of Neurological Disorders and Stroke criteria TIA/stroke 40 out of 95 (42% [32%â53%]); migraine aura 4 out of 38 (11% [3%â25%]); non-TIA focal symptoms 16 out of 99 (16% [10%â25%]); and no focal features 1 out of 29 (3% [0%â18%]). After MRI, a further 14 (5% [95% CI, 3â8]) would be treated with an antiplatelet drug compared with treatment plan before MRI. By 18 months, a new ischemic stroke occurred in 9 out of 61 (18%) patients with MRI evidence of acute ischemia and 2 out of 211 (1%) without (age-adjusted hazard ratio, 13 [95% CI, 3â62]; P<0.0001). CONCLUSIONS: MRI evidence of acute brain ischemia was found in about 1 in 6 transient or minor neurological symptoms patients with a nonstroke/TIA initial diagnosis or uncertain diagnosis. Methods to determine the clinical and cost-effectiveness of MRI are needed in this population
Popular music, psychogeography, place identity and tourism: The case of Sheffield
Tourism and cultural agencies in some English provincial cities are promoting their popular music âheritageâ and, in some cases, contemporary musicians through the packaging of trails, sites, âiconicâ venues and festivals. This article focuses on Sheffield, a âpost-industrialâ northern English city which is drawing on its associations with musicians past and present in seeking to attract tourists. This article is based on interviews with, among others, recording artists, promoters, producers and venue managers, along with reflective observational and documentary data. Theoretical remarks are made on the representations of popular musicians through cultural tourism strategies, programmes and products and also on the ways in which musicians convey a âpsychogeographicalâ sense of place in the âsoundscapeâ of the city
Effect of cell compression on the water dynamics of a polymer electrolyte fuel cell using in-plane and through-plane in-operando neutron radiography
Water dynamics in the membrane electrode assembly (MEA) and flow channels of polymer electrolyte fuel cells (PEFCs) is governed by the complex interplay of many physical and operational factors. The chemical nature and structure of the gas diffusion layer (GDL) plays a large part in this and is affected by the extent to which is mechanically compressed. Here, X-ray computed tomography shows the effect of cell compression on the MEA, and how it differs under the land and channel regions. Multi-orientation neutron radiography reveals the effect of compression on the way in which water accumulates and is transported between land and channel and between cathode and anode. By performing neutron imaging in both the in-plane and through-plane directions, it is possible to determine what constitutes a given âthicknessâ of water mapped across the extent of an MEA. Changing MEA compression from 25% to 35% has a significant effect on water distribution and dynamics in operational cells. The effect of compression on performance is most marked in the mass transport region, and there are consequences for liquid accumulation in channels and back-diffusion of water from the cathode to the anode
Multi-length scale characterization of compression on metal foam flow-field based fuel cells using X-ray computed tomography and neutron radiography
The mechanical compression of metal foam flow-field based polymer electrolyte fuel cells (PEFCs) is critical in determining the interfacial contact resistance with gas diffusion layers (GDLs), reactant flow and water management. The distinct scale between the pore structure of metal foams and the entire flow-field warrant a multi-length scale characterization that combines ex-situ tests of compressed metal foam samples and in-operando analysis of operating PEFCs using X-ray computed tomography (CT) and neutron radiography. An optimal âmediumâ compression was found to deliver a peak power density of 853 mW cmâ2. The X-ray CT data indicates that the compression process significantly decreases the mean pore size and narrows the pore size distribution of metal foams. Simulation results suggest compressing metal foam increases the pressure drop and gas velocity, improving the convective liquid water removal. This is in agreement with the neutron imaging results that demonstrates an increase in the mass of accumulated liquid water with minimum compression compared to the medium and maximum compression cases. The results show that a balance between Ohmic resistance, water removal capacity and parasitic power is imperative for the optimal performance of metal foam based PEFCs
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