19,727 research outputs found

    Understanding Blazar Jets Through Their Multifrequency Emission

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    Being dominated by non-thermal (synchrotron and inverse Compton) emission from a relativistic jet, blazars offer important clues to the structure and radiative processes in extragalactic jets. Crucial information is provided by blazars' spectral energy distributions from radio to gamma-rays (GeV and TeV energies), their trends with bolometric luminosity, and their correlated variability properties. This review is focussed on recent multiwavelength monitorings of confirmed and candidate TeV blazars and the constraints they provide for the radiative properties of the emitting particles. I also present recent observations of the newly discovered class of ``blue quasars'' and the implications for current blazars' unification schemes.Comment: invited opening talk at the GeV-TeV Astronomy International meeting held at the Snowbird resort, Salt Lake City, Utah, August 199

    Gene expression in large pedigrees: analytic approaches.

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    BackgroundWe currently have the ability to quantify transcript abundance of messenger RNA (mRNA), genome-wide, using microarray technologies. Analyzing genotype, phenotype and expression data from 20 pedigrees, the members of our Genetic Analysis Workshop (GAW) 19 gene expression group published 9 papers, tackling some timely and important problems and questions. To study the complexity and interrelationships of genetics and gene expression, we used established statistical tools, developed newer statistical tools, and developed and applied extensions to these tools.MethodsTo study gene expression correlations in the pedigree members (without incorporating genotype or trait data into the analysis), 2 papers used principal components analysis, weighted gene coexpression network analysis, meta-analyses, gene enrichment analyses, and linear mixed models. To explore the relationship between genetics and gene expression, 2 papers studied expression quantitative trait locus allelic heterogeneity through conditional association analyses, and epistasis through interaction analyses. A third paper assessed the feasibility of applying allele-specific binding to filter potential regulatory single-nucleotide polymorphisms (SNPs). Analytic approaches included linear mixed models based on measured genotypes in pedigrees, permutation tests, and covariance kernels. To incorporate both genotype and phenotype data with gene expression, 4 groups employed linear mixed models, nonparametric weighted U statistics, structural equation modeling, Bayesian unified frameworks, and multiple regression.Results and discussionRegarding the analysis of pedigree data, we found that gene expression is familial, indicating that at least 1 factor for pedigree membership or multiple factors for the degree of relationship should be included in analyses, and we developed a method to adjust for familiality prior to conducting weighted co-expression gene network analysis. For SNP association and conditional analyses, we found FaST-LMM (Factored Spectrally Transformed Linear Mixed Model) and SOLAR-MGA (Sequential Oligogenic Linkage Analysis Routines -Major Gene Analysis) have similar type 1 and type 2 errors and can be used almost interchangeably. To improve the power and precision of association tests, prior knowledge of DNase-I hypersensitivity sites or other relevant biological annotations can be incorporated into the analyses. On a biological level, eQTL (expression quantitative trait loci) are genetically complex, exhibiting both allelic heterogeneity and epistasis. Including both genotype and phenotype data together with measurements of gene expression was found to be generally advantageous in terms of generating improved levels of significance and in providing more interpretable biological models.ConclusionsPedigrees can be used to conduct analyses of and enhance gene expression studies

    The stimulation of creative writing on a third grade level

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    Thesis (Ed.M.)--Boston Universit

    EFL Textbook Evaluation: the Analysis of Tasks Presented in English Textbook

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    The use of English textbook does not only become a guide to the teachers when delivering the materials, but also presents necessary input through various explanations and activities. On the side of the learners, it also influences their attitudes and performance to the materials. This phenomenon challenges the writer to conduct research-based article concerning textbook evaluation to analyze the tasks and the distribution (simple to complex) of tasks presented in English textbook used in senior high school. The findings show that the English textbook entitled Bahasa Inggris SMA/MA/SMK/MAK Kelas X Semester 1 has interesting tasks which meet the objectives in curriculum 2013 and a good distribution of tasks across chapters and the whole book

    Focal Myositis in paediatric age.

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    BACKGROUND: Focal Myositis is a rare pseudotumor of unknown aetiology that is often difficult to diagnose and treat. Typically afflicting people in adulthood, it has occasionally been reported also among children. PURPOSE: the aim of this study is to review the literature of Focal Myositis in paediatric age in order to compare the clinical manifestation and the various treatment suggested by different authors. METHODS: this article describes a 6-year-old boy with focal myositis in gracilis muscle successfully treated by conservative methods, including nocturnal leg traction, intensive physiokinesi therapy and articulated knee orthosis guided to progressive extension. Furthermore a systematic review of literature concerning focal myositis in paediatric age is reported. CONCLUSION: our case and the review of literature suggests that conservative methods should be the first-choice treatment for FM in paediatric age and that surgery should be strictly reserved for selected cases where non-invasive methods have previously faile

    Explaining local manufacturing growth in Chile : the advantages of sectoral diversity

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    This paper investigates whether the agglomeration of economic activity in regional clusters affects long-run manufacturing total factor productivity growth in an emerging market context. It explores a large firm-level panel dataset for Chile during a period characterized by high growth rates and rising regional income inequality (1992-2004). The findings are clear-cut. Locations with greater concentration of a particular sector did not experience faster growth in total factor productivity during this period. Rather, local sector diversity was associated with higher long-run growth in total factor productivity. However, there is no evidence that the diversity effect was driven by the local interaction with a set of suppliers and/or clients. The authors interpret this as evidence that agglomeration economies are driven by other factors, such as the sharing of access to specialized inputs not provided solely by a single sector, such as skills or financing.Labor Policies,Economic Theory&Research,Economic Growth,Political Economy,Achieving Shared Growth
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