12 research outputs found

    The elegans of spindle assembly

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    The Caenorhabditis elegans one-cell embryo is a powerful system in which to study microtubule organization because this large cell assembles both meiotic and mitotic spindles within the same cytoplasm over the course of 1 h in a stereotypical manner. The fertilized oocyte assembles two consecutive acentrosomal meiotic spindles that function to reduce the replicated maternal diploid set of chromosomes to a single-copy haploid set. The resulting maternal DNA then unites with the paternal DNA to form a zygotic diploid complement, around which a centrosome-based mitotic spindle forms. The early C. elegans embryo is amenable to live-cell imaging and electron tomography, permitting a detailed structural comparison of the meiotic and mitotic modes of spindle assembly

    Prevalence and community variation in harmful levels of family conflict witnessed by children: implications for prevention

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     AbstractChildren’s reports of high family conflict consistently predict poor outcomes. The study identified criteria for high family conflict based on prospective prediction of increased risk for childhood depression. These criteria were subsequently used to establish the prevalence of high family conflict in Australian communities and to identify community correlates suitable for targeting prevention programs. Study 1 utilised a longitudinal design. Grade 6 and 8 students completed a family conflict scale (from the widely used Communities That Care survey) in 2003 and depression symptomotology were evaluated at a 1-year follow-up (International Youth Development Study, N = 1,798). Receiver-operating characteristic analysis yielded a cut-off point on a family conflict score with depression symptomatology as a criterion variable. A cut-off score of 2.5 or more (on a scale of 1 to 4) correctly identified 69 % with depression symptomology, with a specificity of 77.2 % and sensitivity at 44.3 %. Study 2 used data from an Australian national survey of Grade 6 and 8 children (Healthy Neighbourhoods Study, N = 8,256). Prevalence estimates were calculated, and multivariate logistic regression with multi-level modelling was used to establish factors associated with community variation in family conflict levels. Thirty-three percent of Australian children in 2006 were exposed to levels of family conflict that are likely to increase their future risk for depression. Significant community correlates for elevated family conflict included Indigenous Australian identification, socioeconomic disadvantage, urban and state location, maternal absence and paternal unemployment. The analysis provides indicators for targeting family-level mental health promotion programs

    Family Violence and Children’s Behavior Problems: Independent Contributions of Intimate Partner and Child-Directed Physical Aggression

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    Using data from a diverse sample of 581 families living in predominantly low-income, rural communities, the current study sought to investigate the longitudinal associations among father-perpetrated intimate partner violence (IPV) and child-directed physical aggression perpetrated by the mother. The unique contributions of each of these types of family violence on children’s behavioral problems at school entry were also examined. Results confirm bidirectional associations between father-perpetrated IPV and maternal physical aggression directed toward the child, and indicate that both types of physical aggression contribute to child behavior problems at school entry

    Situação de crianças e adolescentes brasileiros em relação à saúde mental e à violência The situation of Brazilian children and adolescents with regard to mental health and violence

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    Este artigo reflete sobre as violências cometidas contra crianças e adolescentes brasileiros e suas repercussões sobre a saúde mental, propondo um debate sobre a necessidade das políticas públicas de saúde priorizarem temáticas de tamanha relevância. No país, tem-se verificado que a discussão dos temas "violência e problemas de saúde mental em crianças e adolescentes" vem ocorrendo de forma fragmentada e pouco consistente. Este trabalho traz uma seleção não sistemática de estudos epidemiológicos desenvolvidos em escolas e comunidades brasileiras sobre o assunto. A ampla variedade e a prevalência da violência familiar e comunitária e dos problemas de saúde mental são apontadas, ressaltando-se as diferenças metodológicas dos métodos de aferição e a concentração de estudos nas regiões sul e sudeste do país. A ainda escassa rede de atendimento para os problemas aqui tratados é sinalizada, assim como a falta de preocupação com a prevenção do transtorno mental e com a promoção da saúde mental.<br>This article reflects about the situation of mental health and violence against Brazilian children and adolescents, proposing a discussion about the need for public health policies including these extremely relevant issues in their priority agenda. In Brazil, the debate about this problem has occurred in a fragmented and not very consistent way. This article presents a non-systematic selection of epidemiological investigations on this subject conducted in Brazilian schools and communities. The great variety and prevalence of familiar and community violence and of mental health problems is pointed out and the methodological differences between the studies and the concentration of studies in the South and Southeastern regions of the country are emphasized. The article still highlights to the scarce service network for dealing with this kind of problem and the lack of concern with the prevention of mental disorders and promotion of mental health

    Control of microtubule organization and dynamics : two ends in the limelight

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    Microtubules have fundamental roles in many essential biological processes, including cell division and intracellular transport. They assemble and disassemble from their two ends, denoted the plus end and the minus end. Significant advances have been made in our understanding of microtubule plus-end-tracking proteins (+TIPs) such as end-binding protein 1 (EB1), XMAP215, selected kinesins and dynein. By contrast, information on microtubule minus-end-targeting proteins (-TIPs), such as the calmodulin-regulated spectrin-associated proteins (CAMSAPs) and Patronin, has only recently started to emerge. Here, we review our current knowledge of factors, including microtubule-targeting agents, that associate with microtubule ends to control the dynamics and function of microtubules during the cell cycle and development

    Control of microtubule organization and dynamics: two ends in the limelight

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    Signaling by Rod and Cone Photoreceptors: Opsin Properties, G-protein Assembly, and Mechanisms of Activation

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