7,444 research outputs found

    Tourism partnerships and small firms: Power, participation and partition

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    Partnerships have been a central feature of the tourism public policy landscape in advanced capitalist countries for some time. The intuitively appealing argument is that, by sharing expertise and decision making, commitment to the local tourism project is ensured. By participating in partnership working, small firms - which are almost universally characteristic of the sector - are said to contribute to the form and competitiveness of the tourism offer. Drawing on a variety of sources, this paper argues that in most cases such assertions are misplaced because 'partnerships' organized by the public sector are often predicated on an inadequate conceptualization of small firms in tourism, fail to appreciate the importance and complexity of informal economic relations, and usually ignore the particular power relations at play in local tourism policy formation and change

    Learning from visiting speakers: the case of events management

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    Quantification of fracture interaction using stress intensity factor variation maps

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    Accurate and flexible models of fracture interaction are sought after in the fields of mechanics and geology. Stress intensity factors (SIFs) quantify the energy concentrated at the fracture tips and are perturbed from their isolated values when two fractures are close to one another. Using a three-dimensional finite element fracture mechanics code to simulate static fractures in tension and compression, interaction effects are examined. SIF perturbations are characterized by introducing three interaction measures: the circumferential and maximum SIF perturbation provide the “magnitude” of the effect of interaction, and the amplification to shielding ratio quantifies the balance between increased and decreased SIFs along the tip. These measures are used to demonstrate the change in interaction with fracture separation and to find the separation at which interaction becomes negligible. Interaction maps are constructed by plotting the values of the interaction measures for a static fracture as a second fracture is moved around it. These maps are presented for several common fracture orientations in tension. They explore interaction by highlighting regions in which growth is more likely to occur and where fractures will grow into nonplanar geometries. Interaction maps can be applied to fracture networks with multiple discontinuities to analyze the effect of geometric variations on fracture interaction

    Secondary peritoneal hydatidosis, the challenges of echinococcal disease in South Sudan: A case report

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    A 28 year old male presented to the Juba Teaching Hospital with progressive shortness of breath. 18 months prior to admission, he presented to a rural hospital with severe abdominal pain. An emergency laparotomy was  performed, and a large hepatic cyst was removed. Examination at the Juba Teaching hospital revealed a grossly distended abdomen with multiple palpable masses per abdomen. An Abdominal Ultrasound revealed multiple loculated cysts throughout the abdomen. A diagnosis of Secondary Peritoneal Hydatidosis resulting from incorrectly performed surgery was made. The patient was conservatively treated and at 14 weeks, the cysts showed a  moderate reduction in size. Cystic Echinococcus(CE) is common in South Sudan and has a considerable disease burden throughout the developing world. Greater governmental and international support is required to develop effective control measures for these diseases

    'It's on your conscience all the time': a systematic review of qualitative studies examining views on obesity among young people aged 12-18 years in the UK

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    OBJECTIVE: To explore the perspectives of young people in the UK on obesity, body size, shape and weight. DESIGN: Systematic review of qualitative studies using thematic synthesis. DATA SOURCES: Sensitive searches of 18 electronic databases from 1997 to February 2010 supplemented by grey literature searches. STUDY SELECTION: Studies produced since 1997 using qualitative methods to collect perspectives of people aged 12-18 years in the UK, reporting methods for data collection or analysis. Studies of people with eating disorders and those rated low in reliability and usefulness were excluded. RESULTS: Searches identified 30 studies involving over 1400 young people from a range of contexts. Young people of all sizes placed considerable emphasis on personal responsibility, and on the social, rather than health implications of being overweight. Young people with experience of obesity described severe, unrelenting, size-related abuse and isolation. Regardless of their own size, young people were judgemental of individuals who were overweight, but those with experience of obesity described an environment that contained multiple barriers to weight loss. Only one study asked young people directly what might support them to have a healthy body size. Study findings were configured under three main themes, labelled with quotes from included studies: general perceptions of size and society's responses ('It's on your conscience all the time'); the experiences of young people who were overweight ('If I had the choice I wouldn't be this size') and these larger young people's experiences of trying to loose weight and suggestions for action ('Make sure, even when it's hard, you've got people there'). CONCLUSIONS: The perspectives of young people in the UK, when synthesised across the spectrum of body sizes, paint a picture of a stigmatising and abusive social world. Research and policy need to engage young people actively so as to address the social implications of obesity

    Atomistic study on the pressure dependence of the melting point of NdFe12

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    We investigated, using molecular dynamics, how pressure affects the melting point of the recently theorised and epitaxially grown structure NdFe12. We modified Morse potentials using experimental constants and a genetic algorithm code, before running two-phase solid-liquid coexistence simulations of NdFe12 at various temperatures and pressures. The refitting of the Morse potentials allowed us to significantly improve the accuracy in predicting the melting temperature of the constituent elements

    Evolution by leaps : gene duplication in bacteria

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    © 2009 The Authors. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biology Direct 4 (2009): 46, doi:10.1186/1745-6150-4-46.Sequence related families of genes and proteins are common in bacterial genomes. In Escherichia coli they constitute over half of the genome. The presence of families and superfamilies of proteins suggest a history of gene duplication and divergence during evolution. Genome encoded protein families, their size and functional composition, reflect metabolic potentials of the organisms they are found in. Comparing protein families of different organisms give insight into functional differences and similarities. Equivalent enzyme families with metabolic functions were selected from the genomes of four experimentally characterized bacteria belonging to separate genera. Both similarities and differences were detected in the protein family memberships, with more similarities being detected among the more closely related organisms. Protein family memberships reflected known metabolic characteristics of the organisms. Differences in divergence of functionally characterized enzyme family members accounted for characteristics of taxa known to differ in those biochemical properties and capabilities. While some members of the gene families will have been acquired by lateral exchange and other former family members will have been lost over time, duplication and divergence of genes and functions appear to have been a significant contributor to the functional diversity of today’s microbes. Protein families seem likely to have arisen during evolution by gene duplication and divergence where the gene copies that have been retained are the variants that have led to distinct bacterial physiologies and taxa. Thus divergence of the duplicate enzymes has been a major process in the generation of different kinds of bacteria.This research was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-08ER64511

    Quantum whistling in superfluid 4He

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    Fundamental considerations predict that macroscopic quantum systems such as superfluids and the electrons in superconductors will exhibit oscillatory motion when pushed through a small constriction. Here we report the observation of these oscillations between two reservoirs of superfluid 4He partitioned by an array of nanometer-sized apertures. They obey the Josephson frequency equation and are coherent amongst all the apertures. This discovery at the relatively high temperature of 2K (2000 times higher than related phenomena in 3He) may pave the way for a new class of practical rotation sensors of unprecedented precision.Comment: 6 pages, 3 figures, to be published in Natur

    Longitudinal Atomic Beam Spin Echo Experiments: A possible way to study Parity Violation in Hydrogen

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    We discuss the propagation of hydrogen atoms in static electric and magnetic fields in a longitudinal atomic beam spin echo (lABSE) apparatus. Depending on the choice of the external fields the atoms may acquire both dynamical and geometrical quantum mechanical phases. As an example of the former, we show first in-beam spin rotation measurements on atomic hydrogen, which are in excellent agreement with theory. Additional calculations of the behaviour of the metastable 2S states of hydrogen reveal that the geometrical phases may exhibit the signature of parity-(P-)violation. This invites for possible future lABSE experiments, focusing on P-violating geometrical phases in the lightest of all atoms.Comment: 6 pages, 4 figure

    Local spread of classical swine fever upon virus introduction into The Netherlands: Mapping of areas at high risk

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    Background In the recent past, the introduction of Classical Swine Fever Virus (CSFV) followed by between-herd spread has given rise to a number of large epidemics in The Netherlands and Belgium. Both these countries are pork-exporting countries. Particularly important in these epidemics has been the occurrence of substantial "neighborhood transmission" from herd to herd in the presence of base-line control measures prescribed by EU legislation. Here we propose a calculation procedure to map out "high-risk areas" for local between-herd spread of CSFV as a tool to support decision making on prevention and control of CSFV outbreaks. In this procedure the identification of such areas is based on an estimated inter-herd distance dependent probability of neighborhood transmission or "local transmission". Using this distance-dependent probability, we derive a threshold value for the local density of herds. In areas with local herd density above threshold, local transmission alone can already lead to epidemic spread, whereas in below-threshold areas this is not the case. The first type of area is termed 'high-risk' for spread of CSFV, while the latter type is termed 'low-risk'. Results As we show for the case of The Netherlands, once the distance-dependent probability of local transmission has been estimated from CSFV outbreak data, it is possible to produce a map of the country in which areas of high-risk herds and of low-risk herds are identified. We made these maps even more informative by estimating border zones between the two types of areas. In these border zones the risk of local transmission of infection to a nearby high-risk area exceeds a certain level. Conclusion The risk maps provide an easily understandable visualization of the spatial heterogeneities in transmission risk. They serve as a tool for area-specific designs of control strategies, and possibly also for spatial planning of areas where livestock farming is allowed. Similar risk maps can in principl
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