Ethnic identity, school connectedness, and achievement in standardized tests among Mexican-origin youth.

OBJECTIVE: The aim of this study was to investigate the association between school connectedness and performance in standardized test scores and whether this association was moderated by ethnic private regard. METHOD: The study combines self-report data with school district reported data on standardized test scores in reading and math and free and reduced lunch status. Participants included 436 Mexican-origin youth attending a middle school in a southwestern U.S. state. Participants were on average 12.34 years of age (SD = .95) and 51.8% female and 48.2% male. RESULTS: After controlling for age, gender, free and reduced lunch status, and generational status, school connectedness and ethnic private regard were both positive predictors of standardized test scores in reading and math. Results also revealed a significant interaction between school connectedness and ethnic private regard in predicting standardized test scores in reading, such that participants who were low on ethnic private regard and low on school connectedness reported lower levels of achievement compared to participants who were low on ethnic private regard but high on school connectedness. At high levels of ethnic private regard, high or low levels of school connectedness were not associated with higher or lower standardized test scores in reading. CONCLUSION: The findings in this study provide support for the protective role that ethnic private regard plays in the educational experiences of Mexican-origin youth and highlights how the local school context may play a role in shaping this finding. (PsycINFO Database Record

The dynamics and biophysics of shape formation: Common themes in plant and animal morphogenesis.

The emergence of tissue form in multicellular organisms results from the complex interplay between genetics and physics. In both plants and animals, cells must act in concert to pattern their behaviors. Our understanding of the factors sculpting multicellular form has increased dramatically in the past few decades. From this work, common themes have emerged that connect plant and animal morphogenesis-an exciting connection that solidifies our understanding of the developmental basis of multicellular life. In this review, we will discuss the themes and the underlying principles that connect plant and animal morphogenesis, including the coordination of gene expression, signaling, growth, contraction, and mechanical and geometric feedback.

Ensconsin-dependent changes in microtubule organization and LINC complex-dependent changes in nucleus-nucleus interactions result in quantitatively distinct myonuclear positioning defects.

Nuclear movement is a fundamental process of eukaryotic cell biology. Skeletal muscle presents an intriguing model to study nuclear movement because its development requires the precise positioning of multiple nuclei within a single cytoplasm. Furthermore, there is a high correlation between aberrant nuclear positioning and poor muscle function. Although many genes that regulate nuclear movement have been identified, the mechanisms by which these genes act are not known. Using Drosophila melanogaster muscle development as a model system and a combination of live-embryo microscopy and laser ablation of nuclei, we have found that clustered nuclei encompass at least two phenotypes that are caused by distinct mechanisms. Specifically, Ensconsin is necessary for productive force production to drive any movement of nuclei, whereas Bocksbeutel and Klarsicht are necessary to form distinct populations of nuclei that move to different cellular locations. Mechanistically, Ensconsin regulates the number of growing microtubules that are used to move nuclei, whereas Bocksbeutel and Klarsicht regulate interactions between nuclei.

High-Resolution Imaging Methods to Analyze LINC Complex Function During Drosophila Muscle Development.

Using Drosophila muscle development as a model system makes possible the identification of genetic pathways, temporal regulation of development, mechanisms of cellular development, and physiological impacts in a single system. Here we describe the basic techniques for the evaluation of the cellular development of muscle in Drosophila in both embryos and in larvae. These techniques are discussed within the context of how the LINC complex contributes to muscle development.

Emery-Dreifuss muscular dystrophy-linked genes and centronuclear myopathy-linked genes regulate myonuclear movement by distinct mechanisms.

Muscle cells are a syncytium in which the many nuclei are positioned to maximize the distance between adjacent nuclei. Although mispositioned nuclei are correlated with many muscle disorders, it is not known whether this common phenotype is the result of a common mechanism. To answer this question, we disrupted the expression of genes linked to Emery-Dreifuss muscular dystrophy (EDMD) and centronuclear myopathy (CNM) in Drosophila and evaluated the position of the nuclei. We found that the genes linked to EDMD and CNM were each necessary to properly position nuclei. However, the specific phenotypes were different. EDMD-linked genes were necessary for the initial separation of nuclei into distinct clusters, suggesting that these factors relieve interactions between nuclei. CNM-linked genes were necessary to maintain the nuclei within clusters as they moved toward the muscle ends, suggesting that these factors were necessary to maintain interactions between nuclei. Together these data suggest that nuclear position is disrupted by distinct mechanisms in EDMD and CNM.

The nucleus is a conserved mechanosensation and mechanoresponse organelle.

Cells in vivo exist in a dynamic environment where they experience variable mechanical influences. The precise mechanical environment influences cell-cell interactions, cell-extracellular matrix interactions, and in-turn, cell morphology and cell function. Therefore, the ability of each cell to constantly and rapidly alter their behavior in response to variations in their mechanical environment is essential for cell viability, development, and function. Mechanotransduction, the process by which mechanical force is translated into a biochemical signal to activate downstream cellular responses, is thus crucial to cell function during development and homeostasis. Although much research has focused on how protein complexes at the cell cortex respond to mechanical stress to initiate mechanotransduction, the nucleus has emerged as crucial to the ability of the cell to perceive and respond to changes in its mechanical environment. This additional method for mechanosensing allows for direct transmission of force through the cytoskeleton to the nucleus, which can increase the speed at which a cell changes its transcriptional profile. This review discusses recent work demonstrating the importance of the nucleus in mediating the cellular response to internal and external force, establishing the nucleus as an important mechanosensing organelle.

The FOOTPRINTS model of pediatric palliative care.

Little is known about the optimal context in which to provide care for the more than 53,000 children who die each year in the United States. Poor training in pediatric palliative care contributes to care that is often fragmented and may neglect the physical, psychosocial, and spiritual needs of the child and family. Pediatric hospice care is frequently not available or not chosen by the family or health care providers. In response to a critical need to move beyond the disease oriented, hospital-based model with a lack of continuity between hospital and community-based medical services, we developed FOOTPRINTS, an innovative program of advanced care planning and care coordination. A continuity physician directs the treatment plan regardless of site of care. Staff members coordinate follow up and communication among hospital and community-based care providers. Spiritual support continues through bereavement. Education in the hospital and community supports provision of excellent palliative care by current providers. Satisfaction with this model of care has been high. More than 90% of health care providers and families perceived that the child and family needs as well as the health care provider needs were met by the advanced care planning process and written care plan. All continuity providers would refer another patient. The FOOTPRINTS program promotes quality of care and family and health care provider satisfaction with care. It has been developed to serve as a "best practice" model for care at life's end.

Body mass index and percentage of body fat as indicators for obesity in an adolescent athletic population.

BACKGROUND: Body mass index (BMI) is widely accepted in determining obesity. Skinfold thickness measurements have been commonly used to determine percentage of body fat. HYPOTHESIS: The authors hypothesize that because BMI does not measure fat directly but relies on body weight alone, a large percentage of athletic adolescents will be misclassified as obese by BMI. DESIGN: Cross-sectional study. METHODS: To compare BMI and skinfold measurements as indicators for obesity in the adolescent athletic population, anthropometric data (height, weight, percentage body fat, age, and sex) were recorded from 33 896 student athletes (average age, 15 years; range, 11-19 years) during preparticipation physical examinations from 1985 to 2003. BMI was calculated from height and weight. Percentage of body fat was determined by measuring skinfold thickness. RESULTS: According to their BMI percentile, 13.31% of adolescent athletes were obese. Using the skinfold method, only 5.95% were obese. Of those classified as obese by the BMI, 62% were considered false positives by the skinfold method. In contrast, there was a 99% probability that the nonobese by BMI would not be obese by the skinfold method (negative predictive value = 0.99). CONCLUSIONS: BMI is a measurement of relative body weight, not body composition. Because lean mass weighs far more than fat, many adolescent athletes are incorrectly classified as obese based on BMI. Skinfold testing provides a more accurate body assessment than BMI in adolescent athletes. CLINICAL RELEVANCE: Correct body composition data can help to provide better diet and activity guidelines and prevent the psychological problems associated with being labeled as obese.