501 research outputs found

    Neutrino masses or new interactions

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    Recent proposals to study the mass of the "electron" neutrino at a sensitivity of 0.3 eV can be used to place limits on the right handed and scalar charged currents at a level which improves on the present experimental limits. Indeed the neglect of the possibility of such interactions can lead to the inference of an incorrect value for the mass, as we illustrate.Comment: 12 pages and 3 figures. Contributed to the XX International Symposium on Lepton and Photon Interactions at High Energies, Rome, July 2001, and to the International Europhysics Conference on High Energy Physics, Budapest, July 2001. Preprint numbers added, misprints correcte

    Neutrino clustering and the Z-burst model

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    The possibility that the observed Ultra High Energy Cosmic Rays are generated by high energy neutrinos creating "Z-bursts" in resonant interactions with the background neutrinos has been proposed, but there are difficulties in generating enough events with reasonable incident neutrino fluxes. We point out that this difficulty is overcome if the background neutrinos have coalesced into "neutrino clouds" --- a possibility previously suggested by some of us in another context. The limitations that this mechanism for the generation of UHECRs places on the high energy neutrino flux, on the masses of the background neutrinos and the characteristics of the neutrino clouds are spelled out.Comment: 13 pages and 3 figures. Contributed to the XX International Symposium on Lepton and Photon Interactions at High Energies, Rome, July 2001, and to the International Europhysics Conference on High Energy Physics, Budapest, July 2001. Preprint numbers added, misprints correcte

    The Paradox of Compacts: final report to the Home Office on monitoring the impact of Compacts

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    The Compact is an important building block in achieving a better relationship between Government and the voluntary and community sector. We are fully committed to partnership working with the sector and increasing their role in civil society and in the delivery of public s e rvices. The Compact helps us to work better together, so that we can better meet the needs of communities

    Epidemiology of injuries in adventure racing athletes

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    OBJECTIVES: To assess the demographics and training characteristics of adventure racing athletes in the United Kingdom, the prevalence and anatomical distribution of hazardous encounter, and overuse injury in this population, and the effects these injuries have on training. METHODS: A retrospective training and injury questionnaire for the previous 18 months was distributed to 300 adventure racing athletes at two national race meetings. The definition of an injury was "any musculoskeletal problem causing a stop in training for at least one day, reduction in training mileage, taking of medicine, or seeking of medical aid." RESULTS: The data were derived from the responses of 223 athletes. Advanced level athletes did 11 (4) sessions and 17 (8) hours of training a week (mean (SD)). An injury was reported in the previous 18 months by 73% of the respondents. The most common site of acute injury was the ankle (23%) and of chronic/overuse injury, the knee (30%), followed by the lower back, shin, and Achilles tendon (12% each). There were significant correlations (p<0.01) between the hours spent cycling per week and number of acute injuries, and between the number of days off per week and number of chronic/overuse injuries. Injuries resulted in an average of 23 days training cessation or reduction. CONCLUSIONS: Acute injuries were sustained mainly as a result of the nature of the terrain over which athletes train and compete. In overuse injuries lack of adequate rest days was a significant contributing factor. Only a small proportion of training time was spent developing flexibility and core stability

    Empirical realised niche models for British coastal plant species

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    Coastal environments host plant taxa adapted to a wide range of salinity conditions. Salinity, along with other abiotic variables, constrains the distribution of coastal plants in predictable ways, with relatively few taxa adapted to the most saline conditions. However, few attempts have been made to quantify these relationships to create niche models for coastal plants. Quantification of the effects of salinity, and other abiotic variables, on coastal plants is essential to predict the responses of coastal ecosystems to external drivers such as sea level rise. We constructed niche models for 132 coastal plant taxa in Great Britain based on eight abiotic variables. Paired measurements of vegetation composition and abiotic variables are rare in coastal habitats so four of the variables were defined using community mean values for Ellenberg indicators, i.e. scores assigned according to the typical alkalinity, fertility, moisture availability and salinity of sites where a species occurs. The remaining variables were the canopy height, annual precipitation, and maximum and minimum temperatures. Salinity and moisture indicator scores were significant terms in over 80 % of models, suggesting the distributions of most coastal species are at least partly determined by these variables. When the models were used to predict species occurrence against an independent dataset 64 % of models gave moderate to good predictions of species occurrence. This indicates that most models had successfully captured the key determinants of the niche. The models could potentially be applied to predict changes to habitats and species-dependent ecosystem services in response to rising sea levels

    Propulsion simulator for magnetically-suspended wind tunnel models

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    In order to demonstrate the measurement of aerodynamic forces/moments, including the effects of exhaust jets in Magnetic Suspension and Balance System (MSBS) wind tunnels, two propulsion simulator models were developed at Physical Sciences Inc. (PSI). Both the small-scale model (1 in. diameter X 8 in. long) and the large-scale model (2.5 in. diameter X 15 in. long) employed compressed, liquefied carbon dioxide as a propellant. The small-scale simulator, made from a highly magnetizable iron alloy, was demonstrated in the 7 in. MSBS wind tunnel at the University of Southampton. It developed a maximum thrust of approximate 1.3 lbf with a 0.098 in. diameter nozzle and 0.7 lbf with a 0.295 in. diameter nozzle. The Southampton MSBS was able to control the simulator at angles-of attack up to 20 deg. The large-scale simulator was demonstrated to operate in both a steady-state and a pulse mode via a miniaturized solinoid valve. It developed a stable and repeatable thrust of 2.75 lbf over a period of 4s and a nozzle pressure ratio (NPR) of 5

    A framework linking ecosystem services and human well‐being: Saltmarsh as a case study

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    1. The ecosystem services approach is based on the interdependencies between nature and human well‐being. However, while the ecosystem services aspect of this approach is well‐developed, the human well‐being aspect remains unstructured and vaguely defined. 2. An integrated conceptual framework was developed by adapting and linking the UK National Ecosystem Assessment‐Follow On framework with human well‐being domains. 3. As well as benefits, the notion of disbenefits was incorporated to recognise the potentially detrimental effects from interacting with nature. Benefits and disbenefits occur at the social–ecological interface and are classified by the seven domains of human well‐being they affect. 4. The framework is applied to saltmarsh habitat as a case study, highlighting knowledge gaps and the potential applicability and usefulness of the framework. In saltmarsh, benefits mainly accrue at larger scales with a greater impact affecting local to global individuals, while disbenefits tend to occur at a smaller scale and impact in‐situ individuals. 5. The framework provides in‐depth insight into links, trade‐offs and dichotomies between benefits and disbenefits and human well‐being, and improves accessibility to the complex research area of human well‐being. 6. This research can be a useful tool to guide environmental and health policy and management, as well as stakeholder engagement

    Oculomotor function in frontotemporal lobar degeneration, related disorders and Alzheimer's disease

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    Frontotemporal lobar degeneration (FTLD) often overlaps clinically with corticobasal syndrome (CBS) and progressive supranuclear palsy (PSP), both of which have prominent eye movement abnormalities. To investigate the ability of oculomotor performance to differentiate between FTLD, Alzheimer's disease, CBS and PSP, saccades and smooth pursuit were measured in three FTLD subtypes, including 24 individuals with frontotemporal dementia (FTD), 19 with semantic dementia (SD) and six with progressive non-fluent aphasia (PA), as compared to 28 individuals with Alzheimer's disease, 15 with CBS, 10 with PSP and 27 control subjects. Different combinations of oculomotor abnormalities were identified in all clinical syndromes except for SD, which had oculomotor performance that was indistinguishable from age-matched controls. Only PSP patients displayed abnormalities in saccade velocity, whereas abnormalities in saccade gain were observed in PSP > CBS > Alzheimer's disease subjects. All patient groups except those with SD were impaired on the anti-saccade task, however only the FTLD subjects and not Alzheimer's disease, CBS or PSP groups, were able to spontaneously self-correct anti-saccade errors as well as controls. Receiver operating characteristic statistics demonstrated that oculomotor findings were superior to neuropsychological tests in differentiating PSP from other disorders, and comparable to neuropsychological tests in differentiating the other patient groups. These data suggest that oculomotor assessment may aid in the diagnosis of FTLD and related disorders

    The white dwarf binary pathways survey -- X. Gaia orbits for known UV excess binaries

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    White dwarfs with a F, G or K type companion represent the last common ancestor for a plethora of exotic systems throughout the galaxy, though to this point very few of them have been fully characterised in terms of orbital period and component masses, despite the fact several thousand have been identified. Gaia data release 3 has examined many hundreds of thousands of systems, and as such we can use this, in conjunction with our previous UV excess catalogues, to perform spectral energy distribution fitting in order to obtain a sample of 206 binaries likely to contain a white dwarf, complete with orbital periods, and either a direct measurement of the component masses for astrometric systems, or a lower limit on the component masses for spectroscopic systems. Of this sample of 206, four have previously been observed with Hubble Space Telescope spectroscopically in the ultraviolet, which has confirmed the presence of a white dwarf, and we find excellent agreement between the dynamical and spectroscopic masses of the white dwarfs in these systems. We find that white dwarf plus F, G or K binaries can have a wide range of orbital periods, from less than a day to many hundreds of days. A large number of our systems are likely post-stable mass transfer systems based on their mass/period relationships, while others are difficult to explain either via stable mass transfer or standard common envelope evolution.Comment: 17 pages, 10 figures, Accepted for publication in MNRA
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