326 research outputs found

    Genome scan of Diabrotica virgifera virgifera for genetic variation associated with crop rotation tolerance

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    Crop rotation has been a valuable technique for control of Diabrotica virgifera virgifera for almost a century. However, during the last two decades, crop rotation has ceased to be effective in an expanding area of the US corn belt. This failure appears to be due to a change in the insect's oviposition behaviour, which, in all probability, has an underlying genetic basis. A preliminary genome scan using 253 amplified fragment-length polymorphism (AFLP) markers sought to identify genetic variation associated with the circumvention of crop rotation. Samples of D. v. virgifera from east-central Illinois, where crop rotation is ineffective, were compared with samples from Iowa at locations that the behavioural variant has yet to reach. A single AFLP marker showed signs of having been influenced by selection for the circumvention of crop rotation. However, this marker was not diagnostic. The lack of markers strongly associated with the trait may be due to an insufficient density of marker coverage throughout the genome. A weak but significant general heterogeneity was observed between the Illinois and Iowa samples at microsatellite loci and AFLP markers. This has not been detected in previous population genetic studies of D. v. virgifera and may indicate a reduction in gene flow between variant and wild-type beetles

    The Observation of Up-going Charged Particles Produced by High Energy Muons in Underground Detectors

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    An experimental study of the production of up-going charged particles in inelastic interactions of down-going underground muons is reported, using data obtained from the MACRO detector at the Gran Sasso Laboratory. In a sample of 12.2 10^6 single muons, corresponding to a detector livetime of 1.55 y, 243 events are observed having an up-going particle associated with a down-going muon. These events are analysed to determine the range and emission angle distributions of the up-going particle, corrected for detection and reconstruction efficiency. Measurements of the muon neutrino flux by underground detectors are often based on the observation of through-going and stopping muons produced in νμ\nu_\mu interactions in the rock below the detector. Up-going particles produced by an undetected down-going muon are a potential background source in these measurements. The implications of this background for neutrino studies using MACRO are discussed.Comment: 18 pages, 9 figures. Accepted by Astrop. Physic

    Atmospheric neutrino induced muons in the MACRO detector

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    A measurement of the flux of neutrino-induced muons using the MACRO detector is presented. Different event topologies, corresponding to different neutrino parent energies can be detected. The upward throughgoing muon sample is the larger event sample. The observed upward-throughgoing muons are 26% fewer than expected and the zenith angle distribution does not fit with the expected one. Assuming neutrino oscillations, both measurements suggest maximum mixing and Dm2 of a few times 10-3 eV2. The other samples are due to the internally produced events and to upward-going stopping muons. These data show a regular deficit of observed events in each angular bin, as expected assuming neutrino oscillations with maximum mixing, in agreement with the analysis of the upward-throughgoing muon sample.Comment: 7 pages 6 figures to appear in the proceedings of XVIII International Conference on Neutrino Physics and Astrophysics (Neutrino'98), Takayama, Japan 4-9 June, 199

    From rehabilitation to recovery: protocol for a randomised controlled trial evaluating a goal-based intervention to reduce depression and facilitate participation post-stroke

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    <p>Abstract</p> <p>Background</p> <p>There is much discourse in healthcare about the importance of client-centred rehabilitation, however in the realm of community-based therapy post-stroke there has been little investigation into the efficacy of goal-directed practice that reflects patients' valued activities. In addition, the effect of active involvement of carers in such a rehabilitation process and their subsequent contribution to functional and emotional recovery post-stroke is unclear. In community based rehabilitation, interventions based on patients' perceived needs may be more likely to alter such outcomes. In this paper, we describe the methodology of a randomised controlled trial of an integrated approach to facilitating patient goal achievement in the first year post-stroke. The effectiveness of this intervention in reducing the severity of post-stroke depression, improving participation status and health-related quality of life is examined. The impact on carers is also examined.</p> <p>Methods/Design</p> <p>Patients (and their primary carers, if available) are randomly allocated to an intervention or control arm of the study. The intervention is multimodal and aims to screen for adverse stroke sequelae and address ways to enhance participation in patient-valued activities. Intervention methods include: telephone contacts, written information provision, home visitation, and contact with treating health professionals, with further relevant health service referrals as required. The control involves treatment as usual, as determined by inpatient and community rehabilitation treating teams. Formal blinded assessments are conducted at discharge from inpatient rehabilitation, and at six and twelve months post-stroke. The primary outcome is depression. Secondary outcome measures include participation and activity status, health-related quality of life, and self-efficacy.</p> <p>Discussion</p> <p>The results of this trial will assist with the development of a model for community-based rehabilitation management for stroke patients and their carers, with emphasis on goal-directed practice to enhance home and community participation status. Facilitation of participation in valued activities may be effective in reducing the incidence or severity of post-stroke depression, as well as enhancing the individual's perception of their health-related quality of life. The engagement of carers in the rehabilitation process will enable review of the influence of the broader social context on recovery.</p> <p>Trial registration</p> <p>Australia and New Zealand Clinical Trials Register (ANZCTR): <a href="http://www.anzctr.org.au/ACTRN12608000042347.aspx">ACTRN12608000042347</a></p

    Knowledge and perceptions of diabetes in a semi-urban Omani population

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    <p>Abstract</p> <p>Background</p> <p>Diabetes mellitus is a major public health problem in the Sultanate of Oman. This study aimed to evaluate the knowledge and perception of diabetes in a sample of the Omani general population, and the associations between the elements of knowledge and perception, and socio-demographic factors.</p> <p>Methods</p> <p>The study was carried out in two semi-urban localities. A total of 563 adult residents were interviewed, using a questionnaire specifically designed for the present study. In addition to demographic information, the questionnaire contained questions on knowledge related to diabetes definition, symptoms, risk factors, complications and preventative measures, as well as risk perception for diabetes.</p> <p>Results</p> <p>Knowledge of diabetes was suboptimal. The percentages of correct responses to questions on diabetes definition, classical symptoms, and complications were 46.5%, 57.0%, and 55.1%, respectively. Only 29.5%, 20.8% and 16.9% identified obesity, physical inactivity and a positive family history, respectively, as risk factors for diabetes. A higher level of education, a higher household income, and the presence of a family history of diabetes were found to be positively associated with more knowledge.</p> <p>Conclusion</p> <p>This study demonstrated that there is lack of awareness of major risk factors for diabetes mellitus. Level of education is the most significant predictor of knowledge regarding risk factors, complications and the prevention of diabetes. Given that the prevalence of diabetes has increased drastically in Oman over the last decade, health promotion seems essential, along with other means to prevent and control this emerging health problem.</p

    Sosa on Knowledge, Judgment and Guessing

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    In Chapter 3 of Judgment and Agency, Sosa (Judgment and Agency, 2015) explicates the concept of a fully apt performance. In the course of doing so, he draws from illustrative examples of practical performances and applies lessons drawn to the case of cognitive performances, and in particular, to the cognitive performance of judging. Sosa’s examples in the practical sphere are rich and instructive. But there is, I will argue, an interesting disanalogy between the practical and cognitive examples he relies on. Ultimately, I think the source of the disanalogy is a problematic picture of the cognitive performance of guessing and its connection to knowledge and defeat. Once this critical line of argument is advanced, an alternative picture of guessing, qua cognitive performance, is articulated, one which avoids the problems discussed, and yet remains compatible with Sosa’s broader framework

    New MACRO results on atmospheric neutrino oscillations

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    The final results of the MACRO experiment on atmospheric neutrino oscillations are presented and discussed. The data concern different event topologies with average neutrino energies of ~3 and ~50 GeV. Multiple Coulomb Scattering of the high energy muons in absorbers was used to estimate the neutrino energy of each event. The angular distributions, the L/E_nu distribution, the particle ratios and the absolute fluxes all favour nu_mu --> nu_tau oscillations with maximal mixing and Delta m^2 =0.0023 eV^2. A discussion is made on the Monte Carlos used for the atmospheric neutrino flux. Some results on neutrino astrophysics are also briefly discussed.Comment: Invited Paper at the NANP03 Int. Conf., Dubna, 200

    Genetic differentiation among host-associated Alebra leafhoppers (Hemiptera: Cicadellidae)

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    The limited importance ascribed to sympatric speciation pro cesses via host race formation is partially due to the few cases of host races that have been reported among host populations. This work sheds light on the taxonomy of Alebra leafhoppers and examines the possible existence of host races among host-associated populations. The species of this genus show varying degrees of host association with deciduous trees and shrubs and, frequently, host popu lations of uncertain taxonomic status coexist and occasion ally become pests. Allozyme electrophoresis of 21 Greek populations including sympatric, local and geographically distant samples collected on 13 different plant species, show that they represent at least five species: A. albostriella Falle´n, A. viridis (Rey) (sensu Gillham), A. wahlbergi Bo Keywords: host races; leafhoppers; sympatric speciation; sibling species; allozymes; Alebra Introduction Sympatric speciation is a controversial subject in evol utionary biology (see Mayr, 1963; Futuyma and Mayer, 1980; Paterson, 1981; Via, 2001). One of the reasons for this controversy is that sympatric speciation seems to be an extremely rare phenomenon occurring only in very few groups of taxa, represented chiefly by phytophagous insects (Tauber and Tauber, 1977; Menken, 1981; Wood, 1993; Emelianov et al, 1995; Via, 1999; Finchak et al, 2000; Craig et al, 2001). The limited number of reported cases among organisms with sexual reproduction can be at least partially attributed to the fact that taxa undergoing sympatric speciation events must fulfill very restrictive biological and ecological requirements. Most sympatric speciation models demand that there is intraspecific genetic variation in traits that differentially affect the fitness of individuals that colonise new habitats or hosts (Dieckman and Doebeli, 1999; Hawthorne and Via, 2001 but see Higashi et al, 1999 and Takimoto et al, 2000). They assume that selection acting on these traits can prevent genetic exchange between populations (Bush, 1975; Tauber and Tauber, 1977; Diehl and Bush, 1989). In phytophagous insects, this means that host pref erences must be genetically determined and mating should occur on the host (Bush, 1975; Diehl and Bush, Correspondence: D Aguin-Pombo, Department of Biology, University of Madeira, Campus Universitario da Penteada, 9000 Funchal, Madeira, Portugal. E-mail: aguin uma.pt Received 12 December 2000; accepted 13 December 2001 heman and two new species. Of these, one is associated to Quercus frainetto and other is specific to Crataegus spp. Significant genetic differences among sympatric and local host populations were found only in A. albostriella, between populations on Turkey oak, beech and common alder. It is suggested that the last two of these host populations may represent different host races. The results show that both the host plant and geographical distance affect the patterns of differentiation in the genus. The formation of some spec ies seems to have been the result of allopatric speciation events while, for others, their origin can be equally explained either by sympatric or allopatric speciation.info:eu-repo/semantics/publishedVersio

    Structural characterization of vanadium oxide catalysts supported on nanostructured silica SBA-15 using X-ray absorption spectroscopy

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    The local structure of vanadium oxide supported on nanostructured SiO2 (VxOy/SBA-15) was investigated by in situ X-ray absorption spectroscopy (XAS). Because the number of potential parameters in XAS data analysis often exceeds the number of "independent" parameters, evaluating the reliability and significance of a particular fitting procedure is mandatory. The number of independent parameters (Nyquist) may not be sufficient. Hence, in addition to the number of independent parameters, a novel approach to evaluate the significance of structural fitting parameters in XAS data analysis is introduced. Three samples with different V loadings (i.e. 2.7 wt %, 5.4 wt %, and 10.8 wt %) were employed. Thermal treatment in air at 623 K resulted in characteristic structural changes of the V oxide species. Independent of the V loading, the local structure around V centers in dehydrated VxOy/SBA-15 corresponded to an ordered arrangement of adjacent V2O7 units. Moreover, the V2O7 units were found to persist under selective oxidation reaction conditions

    Effectiveness of balance training exercise in people with mild to moderate severity Alzheimer's disease: protocol for a randomised trial

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    BACKGROUND: Balance dysfunction and falls are common problems in later stages of dementia. Exercise is a well-established intervention to reduce falls in cognitively intact older people, although there is limited randomised trial evidence of outcomes in people with dementia. The primary objective of this study is to evaluate whether a home-based balance exercise programme improves balance performance in people with mild to moderate severity Alzheimer's disease. METHODS/DESIGN: Two hundred and fourteen community dwelling participants with mild to moderate severity Alzheimer's disease will be recruited for the randomised controlled trial. A series of laboratory and clinical measures will be used to evaluate balance and mobility performance at baseline. Participants will then be randomized to receive either a balance training home exercise programme (intervention group) from a physiotherapist, or an education, information and support programme from an occupational therapist (control group). Both groups will have six home visits in the six months following baseline assessment, as well as phone support. All participants will be re-assessed at the completion of the programme (after six months), and again in a further six months to evaluate sustainability of outcomes. The primary outcome measures will be the Limits of Stability (a force platform measure of balance) and the Step Test (a clinical measure of balance). Secondary outcomes include other balance and mobility measures, number of falls and falls risk measures, cognitive and behavioural measures, and carer burden and quality of life measures. Assessors will be blind to group allocation. Longitudinal change in balance performance will be evaluated in a sub-study, in which the first 64 participants of the control group with mild to moderate severity Alzheimer's disease, and 64 age and gender matched healthy participants will be re-assessed on all measures at initial assessment, and then at 6, 12, 18 and 24 months. DISCUSSION: By introducing a balance programme at an early stage of the dementia pathway, when participants are more likely capable of safe and active participation in balance training, there is potential that balance performance will be improved as dementia progresses, which may reduce the high falls risk at this later stage. If successful, this approach has the potential for widespread application through community based services for people with mild to moderate severity Alzheimer's disease. TRIAL REGISTRATION: The protocol for this study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12608000040369)
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