816 research outputs found

    Shelf harpacticoid copepods do not escape into the seabed during winter storms

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    Winter storms on temperate shelves frequently rework bottom sediments. When the sediment is put in motion, sediment-dwelling harpacticoid copepods risk being suspended. We tested for evidence that adult harpacticoids move below the layer of reworked sediment to avoid suspension. To do so, we determined the rate at which a moderate storm at a site at 18 m depth in the northern Gulf of Mexico (29° 40.63′N, 84° 22.80′W) exposed subsurface sediment during bed-form development and then subjected intact cores from that site to a similar rate of exposure in a laboratory flume. We found no significant difference in vertical position of the population median for adult males of most species and adult females of all species tested between the eroded and control cores. Even the adult males that moved down did not move far enough and were eroded. We conclude that adult harpacticoids do not shelter from winter storms in the seabed. As they are capable of such behavior, being suspended must be more advantageous than living temporarily at depth in the sediment

    O PAPEL DO TIPO DE RESPOSTA NA FORMA DO CONTRASTE NEGATIVO OU DA INDUÇÃO POSITIVA EM RATOS

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    Rats may decrease (negative contrast) or increase (positive induction) their rate of responding for 1% sucrose reinforcement when 32% sucrose reinforcement is upcoming under different conditions. Previous research suggests that which effect occurs may depend on what motor response (i.e., licking vs. press a lever) isrequired to obtain the sucrose. The present study investigated this idea by having subjects make different responses in different halves of the session. Subjects either licked or pressed a lever for 1% sucrose reinforcement in the first half of the session. They then made the alternative response for 1% or 32% sucrose reinforcement, in different conditions, in the second half. In Experiment 1, both licking and lever pressing were operant responses. In Experiment 2, licking was strictly a consummatory response. Results showed that upcoming 32% sucrose tended to decrease responding for 1% sucrose in the first half of the session regardless of the response required in either half. Positive induction was never observed. The present results question whether type of motor response is a key factor in whether contrast or induction is observed. Instead, they suggest that the location that thesubstances are delivered and consumed is critical. Ultimately, understanding when one effect or the other will occur will enhance our understanding of eating-related behavior.Key words: negative contrast, positive induction, reinforcement, lever press, rat.Ratos podem diminuir (contraste negativo) ou aumentar (indução positiva) sua taxa de respostas reforçadas com solução de sacarose a 1% quando reforçamento com solução de sacarose a 32% é iminente, em diferentes condições. Pesquisa anterior sugere que o efeito que ocorrerá pode depender de qual resposta motora (lamber versus pressionar a barra, por exemplo) é requerida para obter a solução de sacarose. O presente estudo investigou esse problema fazendo os sujeitos emitirem respostas diferentes em cada uma das metades das sessões. Os sujeitos ou lambiam ou pressionavam uma barra e produziam reforçamento de solução de sacarose a 1% na primeira metade da sessão. Eles emitiam, então, a resposta alternativa, reforçada por solução de sacarose a 1% ou 32%, em condições diferentes, na segunda metade da sessão. No Experimento 1, ambos, lamber e pressionar a barra eram respostas operantes. No Experimento 2, lamber foi uma resposta estritamente consumatória. Os resultados mostraram que a solução de sacarose a 32% iminente tendeu a diminuir o responder por solução de sacarose a 1% na primeira metade da sessão, independentemente de qual era a resposta requerida na outra metade. Indução positiva nunca foi observada. Os resultados presentes questionam se o tipo de resposta motora seria um fator chave para a observação de contraste ou de indução, sugerindo, ao contrário, que o local em que as substâncias são liberadas e consumidas seja crítico. Compreender quando um efeito ou outro vai ocorrer aumentará nossa compreensão do comportamento relacionado com alimentar-se. Palavras-chave: Contraste negativo, indução positiva, reforçamento, pressão à barra, rato

    Evaluation of the communications aids project.

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    The Communication Aids Project (CAP) aims ‘to help pupils who have communication difficulties by providing technology to help them access the curriculum and interact with others and support their transition to post-school provision’ (http://cap.becta.org.uk ). The Department for Education and Skills commissioned a team of researchers at University College London and the University of York to carry out an evaluation of CAP to look at the impact, processes and costs of CA

    TcruziDB: an integrated, post-genomics community resource for Trypanosoma cruzi

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    TcruziDB () is an integrated post-genomics database for the parasitic organism, Trypanosoma cruzi, the causative agent of Chagas' disease. TcruziDB was established in 2003 as a flat-file database with tools for mining the unannotated sequence reads and preliminary contig assemblies emerging from the Tri-Tryp genome consortium (TIGR/SBRI/Karolinska). Today, TcruziDB houses the recently published assembled genomic contigs and annotation provided by the genome consortium in a relational database supported by the Genomics Unified Schema (GUS) architecture. The combination of an annotated genome and a relational architecture has facilitated the integration of genomic data with expression data (proteomic and EST) and permitted the construction of automated analysis pipelines. TcruziDB has accepted, and will continue to accept the deposition of genomic and functional genomic datasets contributed by the research community

    Concurrent Validity of the Gambling Functional Assessment (GFA):Correlations with the South Oaks Gambling Screen (SOGS)and Indicators of Diagnostic Efficiency

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    Concurrent validity of the recently introduced Gambling Functional Assessment (GFA) was assessed by comparison with the long-used South Oaks Gambling Screen (SOGS) in two nonclinical adult samples (N = 201, 49% female; N=101, 74% female). Correlations between GFA total scores and its four content scores with SOGS scores were promising (r = .04 to .61), with the content score relating to Escape yielding the highest correlations (.45, .61) and the score relating to Attention yielding the lowest. Performance in the second sample, where the SOGS-defined base rate of pathological gambling (28.7%) was high, was best for Escape scores, which efficiently categorized SOGS-defined cases. The present data suggest that the GFA content area of Escape shows promise at classifying pathological versus nonpathological gambling, while the GFA as a whole may be a useful treatment tool, allowing clinicians to identify the mechanisms that may be maintaining gambling in their patients seeking treatment for pathological gambling

    Observations and simulation of a bottom Ekman layer on a continental shelf

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    A numerical model was used to simulate the bottom Ekman layer of a continental shelf region. The basis for the model was the Mellor and Yamada level 2 « turbulence closure scheme. Conservation equations for momentum, turbulent kinetic energy, and turbulent length scale were utilized in the model. The model was used to simulate data taken from a Cyclesonde mooring on the Peruvian continental shelf in May 1976 as part of the Joint II Coastal Upwelling Ecosystems Analysis program. The Cy-clesonde provided mean horizontal velocity, temperature, salinity, and pressure data. An intense pole-ward undercurrent drove the bottom flow regime. The most striking feature of the data was the clockwise Ekman veering of velocity vectors as the bottom was approached. A 48-hour period was chosen for the model simulations. The vertical profile of speed (48 hours mean) simulated by the model fell within the error bars of the data. The corresponding Ekman spiral display of the model results also showed good agreement with the observati. ons

    An exploratory cluster randomised controlled trial of knowledge translation strategies to support evidence-informed decision-making in local governments (The KT4LG study)

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    Background: Childhood overweight and obesity is the most prevalent and, arguably, politically complex child health problem internationally. Governments, communities and industry have important roles to play, and are increasingly expected to deliver an evidence-informed system-wide prevention program. However, efforts are impeded by a lack of organisational access to and use of research evidence. This study aims to identify feasible, acceptable and ideally, effective knowledge translation (KT) strategies to increase evidence-informed decision making in local governments, within the context of childhood obesity prevention as a national policy priority.Methods/Design: This paper describes the methods for KT4LG, a cluster randomised controlled trial which is exploratory in nature, given the limited evidence base and methodological advances. KT4LG aims to examine a program of KT strategies to increase the use of research evidence in informing public health decisions in local governments. KT4LG will also assess the feasibility and acceptability of the intervention. The intervention program comprises a facilitated program of evidence awareness, access to tailored research evidence, critical appraisal skills development, networking and evidence summaries and will be compared to provision of evidence summaries alone in the control program. 28 local governments were randomised to intervention or control, using computer generated numbers, stratified by budget tertile (high, medium or low). Questionnaires will be used to measure impact, costs, and outcomes, and key informant interviews will be used to examine processes, feasibility, and experiences. Policy tracer studies will be included to examine impact of intervention on policies within relevant government policy documents.Discussion: Knowledge translation intervention studies with a focus on public health and prevention are very few in number. Thus, this study will provide essential data on the experience of program implementation and evaluation of a system-integrated intervention program employed within the local government public health context. Standardised programs of system, organisational and individual KT strategies have not been described or rigorously evaluated. As such, the findings will make a significant contribution to understanding whether a facilitated program of KT strategies hold promise for facilitating evidence-informed public health decision making within complex multisectoral government organisations.<br /

    Acceleration of a stratified current over a sloping bottom, driven by an alongshelf pressure gradient

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    Author Posting. © American Meteorological Society, 2005. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 35 (2005): 1305-1317, doi:10.1175/JPO2744.1.An idealized theoretical model is developed for the acceleration of a two-dimensional, stratified current over a uniformly sloping bottom, driven by an imposed alongshelf pressure gradient and taking into account the effects of buoyancy advection in the bottom boundary layer. Both downwelling and upwelling pressure gradients are considered. For a specified pressure gradient, the model response depends primarily on the Burger number S = Nα/f, where N is the initial buoyancy frequency, α is the bottom slope, and f is the Coriolis parameter. Without stratification (S = 0), buoyancy advection is absent, and the alongshelf flow accelerates until bottom stress balances the imposed pressure gradient. The e-folding time scale to reach this steady state is the friction time, h/r, where h is the water depth and r is a linear bottom friction coefficient. With stratification (S ≠ 0), buoyancy advection in the bottom boundary layer produces vertical shear, which prevents the bottom stress from becoming large enough to balance the imposed pressure gradient for many friction time scales. Thus, the alongshelf flow continues to accelerate, potentially producing large velocities. The acceleration increases rapidly with increasing S, such that even relatively weak stratification (S > 0.2) has a major impact. These results are supported by numerical model calculations.Funding was provided by the Division of Ocean Sciences of the National Science Foundation under Grant OCE-0241292. DCC also received some support from the Office of Naval Research under Grants N00014-00-1-0210 and N00014-02-1-0767
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