995 resultados para 7140-216
Resumo:
Novice and expert jugglers employ different visuomotor strategies: whereas novices look at the balls around their zeniths, experts tend to fixate their gaze at a central location within the pattern (so-called gaze-through). A gaze-through strategy may reflect visuomotor parsimony, i.e., the use of simpler visuomotor (oculomotor and/or attentional) strategies as afforded by superior tossing accuracy and error corrections. In addition, the more stable gaze during a gaze-through strategy may result in more accurate movement planning by providing a stable base for gaze-centered neural coding of ball motion and movement plans or for shifts in attention. To determine whether a stable gaze might indeed have such beneficial effects on juggling, we examined juggling variability during 3-ball cascade juggling with and without constrained gaze fixation (at various depths) in expert performers (n = 5). Novice jugglers were included (n = 5) for comparison, even though our predictions pertained specifically to expert juggling. We indeed observed that experts, but not novices, juggled significantly less variable when fixating, compared to unconstrained viewing. Thus, while visuomotor parsimony might still contribute to the emergence of a gaze-through strategy, this study highlights an additional role for improved movement planning. This role may be engendered by gaze-centered coding and/or attentional control mechanisms in the brain.
Resumo:
Diagnosing psychotic disorders in young people is difficult. High rates of co-morbidity may be one reason for this difficulty, but it may also be the case that current diagnostic categories are not the most useful when approaching the care of young people with psychotic symptoms. The Northern Ireland Early Onset Psychosis Study is the first study to investigate psychotic disorders in children and adolescents in this region. Young people presenting with psychotic symptoms with onset before their 18th birthday were prospectively ascertained over a three-year period (2001-2004). Those who provided informed consent were subject to a diagnostic interview using the Kiddie-Schedule for Affective Disorders and Schizophrenia - Present and Lifetime Version. Twenty-five young people have completed the full assessment process to date. Ten young people met criteria for schizophrenia, 11 for affective psychosis, two for schizoaffective disorder and two for schizophreniform disorder. Twenty-one (80%) subjects also fulfilled criteria for at least one other DSM-IV diagnosis. In conclusion, whilst all subjects met criteria for one or other psychotic disorder, co-morbidity was common in this clinical sample. Greater awareness of the difficulties encountered when trying to reach a diagnosis in this age group may help to improve treatment outcomes.
Resumo:
High rates of hepatocellular carcinoma (HCC) in The Gambia, West Africa, are primarily due to a high prevalence of chronic hepatitis B virus infection and heavy aflatoxin exposure via groundnut consumption. We investigated genetic polymorphisms in carcinogen-metabolizing (GSTM1, GSTT1, HYL1*2) and DNA repair (XRCC1) enzymes in a hospital-based case-control study. Incident HCC cases (n = 216) were compared with frequency-matched controls (n = 408) with no clinically apparent liver disease. Although the prevalence of variant genotypes was generally low, in multivariable analysis (adjusting for demographic factors, hepatitis B virus, hepatitis C virus, and TP53 status), the GSTM1-null genotype [odds ratio (OR), 2.45; 95% confidence interval (95% CI), 1.21-4.95] and the heterozygote XRCC1-399 AG genotype (OR, 3.18; 95% CI, 1.35-7.51) were significantly associated with HCC. A weak association of the HYL1*2 polymorphism with HCC was observed but did not reach statistical significance. GSTT1 was not associated with HCC. The risk for HCC with null GSTM1 was most prominent among those with the highest groundnut consumption (OR, 4.67; 95% CI, 1.45-15.1) and was not evident among those with less than the mean groundnut intake (OR, 0.64; 95% Cl, 0.20-2.02). Among participants who had all three suspected aflatoxin-related high-risk genotypes [GSTM1 null, HLY1*2 (HY/HH), and XRCC1 (AG/GG)], a significant 15-fold increased risk of HCC was observed albeit with imprecise estimates (OR, 14.7; 95% CI, 1.27-169). Our findings suggest that genetic modulation of carcinogen metabolism and DNA repair can alter susceptibility to HCC and that these effects may be modified by environmental factors.
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We report the combined studies of density functional theory (DFT) calculations and electrochemical in situ FTIR spectroscopy on surface oxidants and mechanisms of CO oxidation at the Ru(0001) electrodes. It is shown that CO can co-adsorb with both O and OH species at lower potential region where a low coverage of the (2 x 2)-O/OH adlayer formed; the oxidation of CO adsorbates takes place at higher potentials where a high coverage of the (1 x 1)-O/OH adlayer formed. Surface O species are not the active oxidants under all coverages studied, due to the high reaction barriers between CO and O (>1 eV). However, surface OH species with higher coverage are identified as the active oxidants, and CO oxidation takes place via a two-steps' mechanism of CO + 3OH -> COOH + 2OH -> CO2 + H2O + OH, in which three nearby OH species are involved in the CO2 formation: CO reacts with OH, forming COOH; COOH then transfers the H to a nearby OH to form H2O and CO2, at the same time, another H in the H2O transfers to a nearby OH to form a weak adsorbed H2O and a new OH. The reaction barrier of these processes is reduced significantly to around 0.50 eV. These new results not only provide an insight into surface active oxidants on Ru, which is directly relevant to fuel cell catalysis, but also reveals the extra complexity of catalytic reactions taking place at solid/liquid electrochemical interface in comparison to the relatively simpler ones at solid/gas phase.
Resumo:
Objectives: (1) To determine informal caregivers perceptions about place of care and place of death; and (2) to identify variables associated with a home death among terminally ill individuals who received in-home support services in a publicly funded home care system. Participants and design: A total of 216 informal caregivers participated in a bereavement interview. Data collection included care recipient and informal caregiver characteristics, the use of and satisfaction with community services, and preferences about place of death. Results: Most caregivers reported that they and the care recipient had a preferred place of death (77 and 68%, respectively) with over 63% reporting home as the preferred place of death. Caregivers had a greater preference for an institutional death (14%) than care recipients (4.7%). While 30% of care recipients did not die in their preferred location, most caregivers (92%) felt, in retrospect, that where the care recipient died was the appropriate place of death. Most caregivers reported being satisfied with the care that was provided. The odds of dying at home were greater when the care recipient stated a preference for place of death (OR: 2.92; 95% CI: 1.25, 6.85), and the family physician made home visits during the care recipients last month of life (Univariate odds ratios (OR): 4.42; 95% CI: 1.46, 13.36). Discussion: The ethic of self-control and choice for the care recipient must be balanced with consideration for the well being of the informal caregiver and responsiveness of the community service system. © 2005 Edward Arnold (Publishers) Ltd.
Resumo:
Nociception allows for immediate reflex withdrawal whereas pain allows for longer-term protection via rapid learning. We examine here whether shore crabs placed within a brightly lit chamber learn to avoid one of two dark shelters when that shelter consistently results in shock. Crabs were randomly selected to receive shock or not prior to making their first choice and were tested again over 10 trials. Those that received shock in trial 2, irrespective of shock in trial 1, were more likely to switch shelter choice in the next trial and thus showed rapid discrimination. During trial 1, many crabs emerged from the shock shelter and an increasing proportion emerged in later trials, thus avoiding shock by entering a normally avoided light area. In a final test we switched distinctive visual stimuli positioned above each shelter and/or changed the orientation of the crab when placed in the chamber for the test. The visual stimuli had no effect on choice, but crabs with altered orientation now selected the shock shelter, indicating that they had discriminated between the two shelters on the basis of movement direction. These data, and those of other recent experiments, are consistent with key criteria for pain experience and are broadly similar to those from vertebrate studies. © 2013. Published by The Company of Biologists Ltd.
Resumo:
The relevance of European Union (EU) cross-border cooperation for European border con?ict amelioration may be questioned in the contemporary global climate of threat and insecurity posed by forces of ’dark globalisation’. In any case, empirical evidence exposes the limitations of cross-border cooperation in advancing con?ict amelioration in some border regions. Nevertheless, in an enlarged EU which encompasses Central and East European member states and reaches out to neighbouring states through cross-border cooperation initiatives, the number of real and potential border con?icts with which it is concerned has risen exponentially. Fortunately, there are cases of EU ’borderscapes’ that have adopted a cross-border ’peace-building from below’ approach leading to border con?ict amelioration. Unfortunately, countervailing pressures on EU cross-border cooperation from border security regimes (principally Schengen), the Eurozone crisis, EU budgetary constraints, the conceptualisation of ’Europe as Empire’, and the possible recon?guration of the EU itself compromises this approach. Therefore, the path of European integration may well shift from one of inter-state peace-building and regional crossborder cooperation after the Second World War, to border con?ict and coercion in constituting and reconstituting state borders after the recon?guration of the EU.
Resumo:
A lateral flow immunoassay (LFIA) has been developed and fully validated to detect the primary amnesic shellfish poisoning (ASP) toxin, domoic acid (DA). The performance characteristics of two versions of the test were investigated using spiked and naturally contaminated shellfish (mussels, scallops, oysters, clams, and cockles). The tests provide a qualitative result, to indicate the absence or presence of DA in extracts of shellfish tissues, at concentrations that are relevant to regulatory limits. The new rapid assay (LFIA version 2) was designed to overcome the performance limitations identified in the first version of the assay. The improved test uses an electronic reader to remove the subjective nature of the generated results, and the positive cut-off for screening of DA in shellfish was increased from 10 ppm (version 1) to 17.5 ppm (version 2). A simple extraction and test procedure was employed, which required minimal equipment and materials; results were available 15 min after sample preparation. Stability of the aqueous extracts at room temperature (22 C) at four time points (up to 245 min after extraction) and across a range of DA concentrations was 100.3±1.3% and 98.8±2.4% for pre- and post-buffered extracts, respectively. The assay can be used both within laboratory settings and in remote locations. The accuracy of the new assay, to indicate negative results at or below 10 ppm DA, and positive results at or above 17.5 ppm, was 99.5% (n=216 tests). Validation data were obtained from a 2-day, randomised, blind study consisting of multiple LFIA lots (n=3), readers (n=3) and operators (n=3), carrying out multiple extractions of mussel tissue (n=3) at each concentration (0, 10, 17.5, and 20 ppm). No matrix effects were observed on the performance of the assay with different species (mussels, scallops, oysters, clams, and cockles). There was no impact on accuracy or interference from other phycotoxins, glutamic acid or glutamine with various strip incubations (8, 10, and 12 min). The accuracy of the assay, using naturally contaminated samples to indicate negative results at or below 12.5 ppm and positive results at or above 17.5 ppm, was 100%. Variability between three LFIA lots across a range of DA concentrations, expressed as coefficient of variation (% CV), was 1.1±0.4% (n=2 days) based on quantitative readings from the electronic reader. During an 8 week stability study, accuracy of the method with test strips stored at various temperatures (6, 22, 37 and 50 C) was 100%. Validation for both versions included comparisons with results obtained using reference LC-UV methods. © 2013 Elsevier B.V.
Resumo:
A giant retinal tear (GRT) is a full-thickness neurosensory retinal break that extends circumferentially around the retina for three or more clock hours in the presence of a posteriorly detached vitreous. Its incidence in large population-based studies has been estimated as 1.5% of rhegmatogenous retinal detachments, with a significant male preponderance, and bilaterality in 12.8%. Most GRTs are idiopathic, with trauma, hereditary vitreoretinopathies and high myopia each being causative in decreasing frequency. The vast majority of GRTs are currently managed with a pars plana vitrectomy; the use of adjunctive circumferential scleral buckling is debated, but no studies have shown a clear anatomical or visual advantage with its use. Similarly, silicone oil tamponade does not influence long-term outcomes when compared with gas. Primary and final retinal reattachment rates are achieved in 88% and 95% of patients, respectively. Even when the retina remains attached, however, visual recovery may be limited. Furthermore, fellow eyes of patients with a GRT are at higher risk of developing retinal tears and retinal detachment. Prophylactic treatment under these circumstances may be considered but there is no firm evidence of its efficacy at the present time.
Resumo:
The purpose of the present study was to review systematically, research exploring the relationship between self-concepts and paranoia in psychosis. A literature search was performed by two independent raters in relevant databases (MedLine, PsychInfo and Web of Science) and articles meeting the inclusion criteria were cross-referenced. Following scrutiny according to inclusion criteria, 18 studies were selected for review. A narrative synthesis of findings, in which methodological variability is discussed, is presented relative to three key areas: the nature of the relationship between paranoia and self-concepts; the association between paranoia and discrepancies in self-concepts; the nature of the relationship between paranoia and self-concepts when other, dimensional aspects of these constructs are taken into account. The systematic literature review indicated relatively consistent findings, that paranoia is associated with more negative self-concepts when measured cross-sectionally. Results are somewhat more mixed in regards to research on paranoia and self-concept discrepancies. Studies investigating dimensional aspects of self-concepts and paranoia yield findings of particular interest, especially in regards to the association indicated between instability of self-concepts and paranoia. Limitations in research and of the present systematic review are discussed. Clinical and theoretical implications of findings are outlined and possible directions for future research are suggested.
Resumo:
High temperature co-electrolysis of steam and carbon dioxide using a solid oxide cell (SOC) has been shown to be an efficient route to produce syngas (CO + H-2), which can then be converted to synthetic fuel. Optimization of co-electrolysis requires detailed understanding of the complex reactions, transport processes and degradation mechanisms occurring in the SOC during operation. Thermal imaging, Raman spectroscopy and Diffuse Reflectance Infrared Fourier Transform Spectroscopy are being developed to probe in-situ both the reactions occurring during operation and any associated changes within the structure of the electrodes and electrolyte. Here we discuss the challenges in designing experimental apparatus suitable for high temperature operation with optical spectroscopic access to the areas of the SOC that are of interest. In particular, issues with sealing, temperature gradients, signal strength and cell configuration are discussed and final designs are presented. Preliminary results obtained during co-electrolysis operation are also presented.
Resumo:
This paper investigates the pull-out behaviour (particularly the bearing resistance) of a steel grid reinforcement embedded in silty sand using laboratory tests and numerical analyses. It is demonstrated that the various common analytical equations for calculating the bearing component of pull-out resistance give a wide range of calculated values, up to about 200% disparity. The disparity will increase further if the issue of whether to use the peak or critical state friction angle is brought in. Furthermore, these equations suggest that the bearing resistance factor, N, is only a function of soil friction angle which is not consistent with some design guidelines. In this investigation, a series of large scale laboratory pull-out tests under different test pressures were conducted. The test results unambiguously confirmed that the N factor is a function of test pressure. A modified equation for calculating N is also proposed. To have more in-depth understanding of the pull-out behaviour, the tests were modelled numerically. The input parameters for the numerical analysis were obtained from laboratory triaxial tests. The analysis results were compared with the experimental results. Good agreement between experimental and numerical results was achieved if the strain-softening behaviour from peak strength to critical state condition was captured by the soil model used. © 2013 Elsevier Ltd.