12 research outputs found

    Politial and Economic Aspects of Reading Improvement

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    Elements of Comprehension

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    Relationships Among Need Achievement Themes and Ethnic and Gender Identities in Elementary Literature Series

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    Educators agree that students succeed when reading materials are suitable to their backgrounds and contain ideas that are motivating. Interest in achievement motivation dates back to at least 1910, but until the pioneering work of Atkinson and McClelland, little progress was made in developing achievement motive theory emphasizing both clinical and experimental models (Heckhausen, 1967). McClelland, Atkinson, Clark and Lowell (1953; 1976) formulated the theory of achievement motivation through the use of the Thematic Apperception Test (Murray, 1938) measuring individual differences in the motive to enter an achievement situation. McClelland (1961) defines n-Ach (need achievement) motivation as competition with a standard of excellence. The individual strives to do something well or to accomplish a goal for personal satisfaction, for intrinsic rewards. Achievement motivation theory emphasizes the importance and measurement of individual differences in assessing people\u27s interactions with their environment. The strength of n-Ach is measured by a score devised by coding the thought content of imaginative stories

    Content Area Reading Preparation: Effectiveness of Four Methods of Instruction

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    The belief that secondary content teachers should have content reading as a course in their pre-service education is an idea that is gaining increasing acceptance. Surveys examining certification requirements show that an increasing number of states mandate a course in reading for secondary certification (Bader, 1975; Lamberg, 1978). This trend is also reflected in increased numbers of teacher training institutions that are now offering a content area reading course for their undergraduate secondary education majors, as compared to ten years ago

    Comparison of TNFα to Lipopolysaccharide as an Inflammagen to Characterize the Idiosyncratic Hepatotoxicity Potential of Drugs: Trovafloxacin as an Example

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    Idiosyncratic drug reactions (IDRs) are poorly understood, unpredictable, and not detected in preclinical studies. Although the cause of these reactions is likely multi-factorial, one hypothesis is that an underlying inflammatory state lowers the tolerance to a xenobiotic. Previously used in an inflammation IDR model, bacterial lipopolysaccharide (LPS) is heterogeneous in nature, making development of standardized testing protocols difficult. Here, the use of rat tumor necrosis factor-α (TNFα) to replace LPS as an inflammatory stimulus was investigated. Sprague-Dawley rats were treated with separate preparations of LPS or TNFα, and hepatic transcriptomic effects were compared. TNFα showed enhanced consistency at the transcriptomic level compared to LPS. TNFα and LPS regulated similar biochemical pathways, although LPS was associated with more robust inflammatory signaling than TNFα. Rats were then codosed with TNFα and trovafloxacin (TVX), an IDR-associated drug, and evaluated by liver histopathology, clinical chemistry, and gene expression analysis. TNFα/TVX induced unique gene expression changes that clustered separately from TNFα/levofloxacin, a drug not associated with IDRs. TNFα/TVX cotreatment led to autoinduction of TNFα resulting in potentiation of underlying gene expression stress signals. Comparison of TNFα/TVX and LPS/TVX gene expression profiles revealed similarities in the regulation of biochemical pathways. In conclusion, TNFα could be used in lieu of LPS as an inflammatory stimulus in this model of IDRs

    Isolation of Oct4-Expressing Extraembryonic Endoderm Precursor Cell Lines

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    BACKGROUND:The extraembryonic endoderm (ExEn) defines the yolk sac, a set of membranes that provide essential support for mammalian embryos. Recent findings suggest that the committed ExEn precursor is present already in the embryonic Inner Cell Mass (ICM) as a group of cells that intermingles with the closely related epiblast precursor. All ICM cells contain Oct4, a key transcription factor that is first expressed at the morula stage. In vitro, the epiblast precursor is most closely represented by the well-characterized embryonic stem (ES) cell lines that maintain the expression of Oct4, but analogous ExEn precursor cell lines are not known and it is unclear if they would express Oct4. METHODOLOGY/PRINCIPAL FINDINGS:Here we report the isolation and characterization of permanently proliferating Oct4-expressing rat cell lines ("XEN-P cell lines"), which closely resemble the ExEn precursor. We isolated the XEN-P cell lines from blastocysts and characterized them by plating and gene expression assays as well as by injection into embryos. Like ES cells, the XEN-P cells express Oct4 and SSEA1 at high levels and their growth is stimulated by leukemia inhibitory factor, but instead of the epiblast determinant Nanog, they express the ExEn determinants Gata6 and Gata4. Further, they lack markers characteristic of the more differentiated primitive/visceral and parietal ExEn stages, but exclusively differentiate into these stages in vitro and contribute to them in vivo. CONCLUSIONS/SIGNIFICANCE:Our findings (i) suggest strongly that the ExEn precursor is a self-renewable entity, (ii) indicate that active Oct4 gene expression (transcription plus translation) is part of its molecular identity, and (iii) provide an in vitro model of early ExEn differentiation

    Developments in gas sensor technology for hydrogen safety

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    Gas sensors are applied for facilitating the safe use of hydrogen in, for example, fuel cell and hydrogen fuelled vehicles. New sensor developments, aimed at meeting the increasingly stringent performance requirements in emerging applications are presented based on in-house technical developments and a literature study. The strategy of combining different detection principles, i.e. sensors based on electrochemical cells, semiconductors or field effects in combination with thermal conductivity sensor or catalytic combustion elements, in one new measuring system is reported. This extends the dynamic measuring range of the sensor while improving sensor reliability to achieve higher safety integrity through diverse redundancy. The application of new nanoscaled materials, nano wires, carbon tubes and graphene as well as the improvements in electronic components of fieldeffect, resistive-type and optical systems are evaluated in view of key operating parameters such as sensor response time, low energy consumption and low working temperature.JRC.F.2-Energy Conversion and Storage Technologie
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