119 research outputs found

    Biogeochemical Controls of CO2 Concentrations and Fluxes in an Amazon Floodplain Lake – a Multiscale Approach

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    Purpose. Roles and obstacles to parent involvement at the site level are identified. Methods and strategies for developing parent involvement programs are investigated. Parent, teacher and administrator group perceptions are described and compared. Methodology. Descriptive and comparative surveys address role expectations, potential obstacles, and current parent involvement trends. Parent, teacher, and administrative group responses at Lathrop School are analyzed using mean ranks and median scores for each group. School records for parent involvement activities are examined. Findings. Of the 28 items addressing parent involvement role expectations, eight decision-making, two Parents as Teachers, and one Parents as Learners items show statistically significant differences in group perspectives for role expectations. Of the 31 items analyzing obstacles, group perceptions are different in four areas. Two items show a statistically significant difference among group beliefs in the area of school attitudes. Identification of current parent involvement trends indicate that parents are involved most frequently as Teachers and least frequently as Decision Makers. Recommendations. Lathrop School can use the study to develop clear role expectation guidelines. Suggestions are made for establishing role expectations for all four categories of parent involvement. Recommendations are given for addressing cultural obstacles and suggestions are made for further research and implementation of a more effective parent involvement program

    Sexual dimorphism in cancer.

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    The incidence of many types of cancer arising in organs with non-reproductive functions is significantly higher in male populations than in female populations, with associated differences in survival. Occupational and/or behavioural factors are well-known underlying determinants. However, cellular and molecular differences between the two sexes are also likely to be important. In this Opinion article, we focus on the complex interplay that sex hormones and sex chromosomes can have in intrinsic control of cancer-initiating cell populations, the tumour microenvironment and systemic determinants of cancer development, such as the immune system and metabolism. A better appreciation of these differences between the two sexes could be of substantial value for cancer prevention as well as treatment

    Fatores influenciando a estrutura e distribuição espacial dos peixes nos Igarapés de cabeceira do Parque Nacional do Jaú, Amazônia Central

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    The aim of this study was to investigate the influence of spatial variation in river channels and habitats on the distribution of fish communities in the headwater streams of the Jaú River System, a blackwater tributary of the Negro River. Collections and measurements were made in 34 headwater streams during the period of November-December, 1998. Fish were captured with fish traps and hand nets along standard reaches of two meanders. Data on benthic habitat structure, stream depth and width were collected along lateral transects in each sample reach. A total of 66 fish species from 24 families were collected and classified into seven trophic guilds: allocthonous insectivore, autochthonous insectivore, general insectivore, piscivore, detritivorous planktivore, detritivorous insectivore and insectivorous piscivore. Variations in the distribution and diversity of bottom substrates were important factors influencing fish community structures in these systems. Also, variation in stream size explained the observed variability in fish communities. © 2014, Instituto Internacional de Ecologia. All right reserved

    Diving into the vertical dimension of elasmobranch movement ecology

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    This is the final version. Available on open access from the American Association for the Advancement of Science via the DOI in this recordData and materials availability: Processed data and code used in the analysis are accessible from the Zenodo Repository: 10.5281/zenodo.6885455Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements.Bertarelli FoundationResearch EnglandMoore FoundationPackard FoundationInstituto Politecnico NacionalDarwin InitiativeGeorgia AquariumRolex Awards for EnterpriseWhitley Fund for Natur
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