351 research outputs found

    Skeletal Light-Scattering Accelerates Bleaching Response in Reef-Building Corals

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    Background At the forefront of ecosystems adversely affected by climate change, coral reefs are sensitive to anomalously high temperatures which disassociate (bleaching) photosynthetic symbionts (Symbiodinium) from coral hosts and cause increasingly frequent and severe mass mortality events. Susceptibility to bleaching and mortality is variable among corals, and is determined by unknown proportions of environmental history and the synergy of Symbiodinium- and coral-specific properties. Symbiodinium live within host tissues overlaying the coral skeleton, which increases light availability through multiple light-scattering, forming one of the most efficient biological collectors of solar radiation. Light-transport in the upper ~200 μm layer of corals skeletons (measured as ‘microscopic’ reduced-scattering coefficient, μ′S,m), has been identified as a determinant of excess light increase during bleaching and is therefore a potential determinant of the differential rate and severity of bleaching response among coral species. Results Here we experimentally demonstrate (in ten coral species) that, under thermal stress alone or combined thermal and light stress, low-μ′S,m corals bleach at higher rate and severity than high-μ′S,m corals and the Symbiodinium associated with low-μ′S,m corals experience twice the decrease in photochemical efficiency. We further modelled the light absorbed by Symbiodinium due to skeletal-scattering and show that the estimated skeleton-dependent light absorbed by Symbiodinium (per unit of photosynthetic pigment) and the temporal rate of increase in absorbed light during bleaching are several fold higher in low-μ′S,m corals. Conclusions While symbionts associated with low-μ′S,m corals receive less total light from the skeleton, they experience a higher rate of light increase once bleaching is initiated and absorbing bodies are lost; further precipitating the bleaching response. Because microscopic skeletal light-scattering is a robust predictor of light-dependent bleaching among the corals assessed here, this work establishes μ′S,m as one of the key determinants of differential bleaching response

    College student's academic goals and learning strategies

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    Tomando en cuenta que no existe concordancia en la literatura entre los resultados de diferentes estudios respecto de la relevancia de la adopción de un tipo u otro de meta para el aprendizaje académico, en el presente artículo se estudia la relación entre los diferentes tipos de orientaciones motivacionales (metas de aprendizaje, metas de rendimiento y metas de evitación del trabajo) y el uso de estrategias cognitivas y de autorregulación. En el trabajo participan 632 estudiantes universitarios de diversas titulaciones de la universidad española. Aunque el estudio es de tipo correlacional, los análisis de los datos obtenidos, corroborando estudios anteriores, aportan información de interés para la discusión del problema que se investigó, por ejemplo que sólo los niveles más altos de metas de aprendizaje se encuentran asociados con una mayor utilización de estrategias de aprendizaje. Son discutidas implicaciones educativas de estos datos.Tomando em consideração que não existe concordância na literatura entre os resultados dos diferentes estudos a respeito da relevância da adopção de um ou de outro tipo de meta na aprendizagem académica; no presente artículo é estudada a relação entre os diferentes tipos de orientações motivacionais (metas de aprendizagem, metas de rendimento e metas de evitação do trabalho) e a utilização de estratégias cognitivas e de autoregulação. Neste trabalho participam 632 estudantes universitários de diversas licenciaturas da Universidade espanhola. Apesar de este estudo ser de tipo correlacional, a análise dos dados obtidos, corroborando estudos anteriores, aporta informação de interesse para a discussão do problema investigado; por exemplo que só os níveles mais altos de metas de aprendizagem se encontram associados con uma maior utilização de estratégias de aprendizagem. São discutidas implicações educativas destes dados.Assuming that there isn’t much agreement among the results from different studies relating to the relevance of adopting one or another kind of academic learning goal, this paper intends to study the relationship between the several types of motivational orientations (learning goals, achievement goals and avoidance goals) and the use of cognitive and self-regulatory strategies. 632 Spanish college students from various university courses participated in this research. Although this is a correlacional study data analysis, in line with previous studies, brings to light interesting information and highlights the investigated issue for example only higher levels of learning goals are positively related with the use of learning strategies. Future educational implications are also discussed

    Effects of a Water-Soluble Cinnamon Extract on Body Composition and Features of the Metabolic Syndrome in Pre-Diabetic Men and Women

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    Purpose: The purpose of this study was to determine the effects of supplementation with a water-soluble cinnamon extract (Cinnulin PF®) on body composition and features of the metabolic syndrome. Methods: Twenty-two subjects with prediabetes and the metabolic syndrome (mean ± SD: age, BMI, systolic blood pressure [SBP], fasting blood glucose [FBG]: 46.0 ± 9.7 y; 33.2 ± 9.3 kg/m 2; 133 ± 17 mm Hg; 114.3 ± 11.6 mg/dL) were randomly assigned to supplement their diet with either Cinnulin PF ® (500 mg/d) or a placebo for 12-weeks. Main outcome measures were changes in FBG, SBP, and body composition measured after 12-weeks of supplementation. The primary statistical analyses consisted of two factor (group x time), repeated-measures ANOVA for between group differences over time. In all analyses, an intent-to-treat approach was used and significance was accepted at P<0.05. Results: Subjects in the Cinnulin PF ® group had significant decreases in FBG (-8.4%: 116.3 ± 12.8 mg/dL [pre] to 106.5 ± 20.1 mg/dL [post], p<0.01), SBP (-3.8%: 133 ± 14 mm Hg [pre] to 128 ± 18 mm Hg [post], p<0.001), and increases in lean mass (+1.1%: 53.7 ± 11.8 kg [pre] to 54.3 ± 11.8 kg [post], p<0.002) compared with the placebo group. Additionally, within-group analyses uncovered small, but statistically significant decreases in body fat (-0.7%: 37.9 ± 9.2 % [pre] to 37.2 ± 8.9 % [post], p<0.02) in the Cinnulin PF ® group. No significant changes in clinical blood chemistries were observed betwee

    Evaluation of a Web Portal for Improving Public Access to Evidence-Based Health Information and Health Literacy Skills: A Pragmatic Trial

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    Background: Using the conceptual framework of shared decision-making and evidence-based practice, a web portal was developed to serve as a generic (non disease-specific) tailored intervention to improve the lay public’s health literacy skills. Objective: To evaluate the effects of the web portal compared to no intervention in a real-life setting. Methods: A pragmatic randomised controlled parallel trial using simple randomisation of 96 parents who had children aged ,4 years. Parents were allocated to receive either access to the portal or no intervention, and assigned three tasks to perform over a three-week period. These included a searching task, a critical appraisal task, and reporting on perceptions about participation. Data were collected from March through June 2011. Results: Use of the web portal was found to improve attitudes towards searching for health information. This variable was identified as the most important predictor of intention to search in both samples. Participants considered the web portal to have good usability, usefulness, and credibility. The intervention group showed slight increases in the use of evidencebased information, critical appraisal skills, and participation compared to the group receiving no intervention, but these differences were not statistically significant. Conclusion: Despite the fact that the study was underpowered, we found that the web portal may have a positive effect on attitudes towards searching for health information. Furthermore, participants considered the web portal to be a relevant tool. It is important to continue experimenting with web-based resources in order to increase user participation in health care decision-making. Trial Registration: ClinicalTrials.gov NCT0126679
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