91 research outputs found

    A note on local well-posedness of generalized KdV type equations with dissipative perturbations

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    In this note we report local well-posedness results for the Cauchy problems associated to generalized KdV type equations with dissipative perturbation for given data in the low regularity L2L^2-based Sobolev spaces. The method of proof is based on the {\em contraction mapping principle} employed in some appropriate time weighted spaces.Comment: 14 page

    Parental attributions of control for child behaviour and their relation to discipline practices in parents of children with and without developmental delays

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    Children with developmental delays (DD) are at risk for developing behavior problems. Research suggests that parents’ causal attributions for child behavior are related to parenting. This study investigated this association in parents of children with DD compared to parents of typically developing (TD) children. It specifically focused on attributions of child control by separating these from attributions of responsibility, blame and intent, and from attributions of parent control and responsibility. Fifty-one parents of children with DD and 69 parents of TD children completed two questionnaires. The Written Analogue Questionnaire measured causal attributions. The Parenting Scale measured dysfunctional discipline practices. Parents of children with DD viewed the child’s role in problematic behavior more positively while also viewing misbehavior as more fixed than parents of TD children. Parents of TD children who viewed their child as more in control over misbehavior used less dysfunctional discipline, but this association was not found for parents of children with DD. The results advance understanding of how parents perceive behavior problems in children with DD and the important role these perceptions play in parental behavior management strategies. More importantly, these perceptions relate to discipline practices differently for parents of children with DD compared to parents of TD children, highlighting that parent interventions should be adapted to the specific needs of parents of children with DD

    Large Scale Comparative Codon-Pair Context Analysis Unveils General Rules that Fine-Tune Evolution of mRNA Primary Structure

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    BACKGROUND: Codon usage and codon-pair context are important gene primary structure features that influence mRNA decoding fidelity. In order to identify general rules that shape codon-pair context and minimize mRNA decoding error, we have carried out a large scale comparative codon-pair context analysis of 119 fully sequenced genomes. METHODOLOGIES/PRINCIPAL FINDINGS: We have developed mathematical and software tools for large scale comparative codon-pair context analysis. These methodologies unveiled general and species specific codon-pair context rules that govern evolution of mRNAs in the 3 domains of life. We show that evolution of bacterial and archeal mRNA primary structure is mainly dependent on constraints imposed by the translational machinery, while in eukaryotes DNA methylation and tri-nucleotide repeats impose strong biases on codon-pair context. CONCLUSIONS: The data highlight fundamental differences between prokaryotic and eukaryotic mRNA decoding rules, which are partially independent of codon usage

    To formalize or not to formalize: women entrepreneurs’ sensemaking of business registration in the context of Nepal

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    Despite the depiction of decisions to formalize informal firms as rational and ethical, many entrepreneurs in developing countries continue to operate informally regardless of its perceived illicit status. While existing research on why entrepreneurs choose informality emphasizes the economic costs and benefits of such decisions, this often overlooks the realities of the informal economy and the constraints which marginal populations—particularly women—face. In this paper, we use institutional theory and sensemaking to understand the experiences of women in the informal economy and what formalization means to them. We use a qualitative approach to collect data from 90 women entrepreneurs in three different cities in Nepal. In our findings, we identify three groups of women with distinctive understandings of formalization—business sustainability, livelihood sufficiency and strategic alignment. Their interpretation of formalization reveals the complex, dynamic, and cyclical nature of formalization decisions. Decisions are also guided by the optimization of social and emotional logics, whereby formalization is conceived differently depending on different life stages, experiences within the informal economy and wider socio-cultural contexts. Our findings highlight the ethical implications of formalization where being a ‘good citizen’, rather than complying with formal rules and regulations, is about attuning to and fitting in with socially prescribed roles. Our research provides a nuanced view of formalization decisions, challenging idealized and ethical notions of formalization as a desired end state

    Evaluation of 309 Environmental Chemicals Using a Mouse Embryonic Stem Cell Adherent Cell Differentiation and Cytotoxicity Assay

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    The vast landscape of environmental chemicals has motivated the need for alternative methods to traditional whole-animal bioassays in toxicity testing. Embryonic stem (ES) cells provide an in vitro model of embryonic development and an alternative method for assessing developmental toxicity. Here, we evaluated 309 environmental chemicals, mostly food-use pesticides, from the ToxCast™ chemical library using a mouse ES cell platform. ES cells were cultured in the absence of pluripotency factors to promote spontaneous differentiation and in the presence of DMSO-solubilized chemicals at different concentrations to test the effects of exposure on differentiation and cytotoxicity. Cardiomyocyte differentiation (α,β myosin heavy chain; MYH6/MYH7) and cytotoxicity (DRAQ5™/Sapphire700™) were measured by In-Cell Western™ analysis. Half-maximal activity concentration (AC50) values for differentiation and cytotoxicity endpoints were determined, with 18% of the chemical library showing significant activity on either endpoint. Mining these effects against the ToxCast Phase I assays (∼500) revealed significant associations for a subset of chemicals (26) that perturbed transcription-based activities and impaired ES cell differentiation. Increased transcriptional activity of several critical developmental genes including BMPR2, PAX6 and OCT1 were strongly associated with decreased ES cell differentiation. Multiple genes involved in reactive oxygen species signaling pathways (NRF2, ABCG2, GSTA2, HIF1A) were strongly associated with decreased ES cell differentiation as well. A multivariate model built from these data revealed alterations in ABCG2 transporter was a strong predictor of impaired ES cell differentiation. Taken together, these results provide an initial characterization of metabolic and regulatory pathways by which some environmental chemicals may act to disrupt ES cell growth and differentiation

    Assessment of the Red Cell Proteome of Young Patients with Unexplained Hemolytic Anemia by Two-Dimensional Differential In-Gel Electrophoresis (DIGE)

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    Erythrocyte cytosolic protein expression profiles of children with unexplained hemolytic anemia were compared with profiles of close relatives and controls by two-dimensional differential in-gel electrophoresis (2D-DIGE). The severity of anemia in the patients varied from compensated (i.e., no medical intervention required) to chronic transfusion dependence. Common characteristics of all patients included chronic elevation of reticulocyte count and a negative workup for anemia focusing on hemoglobinopathies, morphologic abnormalities that would suggest a membrane defect, immune-mediated red cell destruction, and evaluation of the most common red cell enzyme defects, glucose-6-phosphate dehydrogenase and pyruvate kinase deficiency. Based upon this initial workup and presentation during infancy or early childhood, four patients classified as hereditary nonspherocytic hemolytic anemia (HNSHA) of unknown etiology were selected for proteomic analysis. DIGE analysis of red cell cytosolic proteins clearly discriminated each anemic patient from both familial and unrelated controls, revealing both patient-specific and shared patterns of differential protein expression. Changes in expression pattern shared among the four patients were identified in several protein classes including chaperons, cytoskeletal and proteasome proteins. Elevated expression in patient samples of some proteins correlated with high reticulocyte count, likely identifying a subset of proteins that are normally lost during erythroid maturation, including proteins involved in mitochondrial metabolism and protein synthesis. Proteins identified with patient-specific decreased expression included components of the glutathione synthetic pathway, antioxidant pathways, and proteins involved in signal transduction and nucleotide metabolism. Among the more than 200 proteins identified in this study are 21 proteins not previously described as part of the erythrocyte proteome. These results demonstrate the feasibility of applying a global proteomic approach to aid characterization of red cells from patients with hereditary anemia of unknown cause, including the identification of differentially expressed proteins as potential candidates with a role in disease pathogenesis

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