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21.
Teacher perceptions of students' intrinsic motivation for reading were examined from the perspective of self-determination development and reading achievement. A sample of 68 teachers from randomly selected elementary schools that were representative of county characteristics rated 374 students on 6 aspects of motivation for reading, including individual, topical, activity-based, autonomy-supported, socially supported, and writing-related aspects. Quantitative and qualitative results showed that teachers perceived higher achievers to be relatively higher in intrinsic reading motivation (individual and topical) than in extrinsic reading motivation (activity-based and autonomy-supported). In contrast, teachers perceived lower achievers to be relatively more motivated by extrinsic contextual factors than by intrinsic factors. Teachers appear to possess implicit theories that are in accord with the self-determination perspective on the development of motivation and reading achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
22.
An 8-year-old girl had acute onset of blurred vision, proptosis, and lateral and vertical gaze palsies on the right. CT and MR examinations showed an expansile mass involving the greater wing of the right sphenoid bone. Pathologic analysis of the surgical specimen revealed a capillary hemangioma. The lesion was inhomogeneous but predominantly isointense with gray matter on T1-weighted images. On T2-weighted images the lesion was inhomogeneous with areas of both high and low signal intensity. The rim enhanced uniformly, and there was inhomogeneous enhancement of the bulk of the lesion. 相似文献
23.
24.
The yield behavior during cold drawing of commercially spun poly(ethylene terephthalate) (PET) filament yarn was investigated. Microscopic examination revealed the presence of inherent flaws within the spun filaments; these act as points for localized stress concentration. These inhomogeneities appear to be either internal cracks or crazes developed during the fiber melt spinning process. During elongation, stress magnification at these flaws results in shear band formation, indicating the onset of inhomogeneous yielding. At the yield bend in the load-elongation curve a circumferential crack propagates within these shear band regions. This yield crack develops into the classical neck geometry which further localizes additional plastic deformation within the sample at the neck. 相似文献
25.
RD Sweet FH McDowell JS Feigenson AW Loranger H Goodell 《Canadian Metallurgical Quarterly》1976,26(4):305-310
The influence of epidural block with bupivacaine (Marcaine-adrenalin) on fetal heart rate, uterine activity, and the frequency and intensity of contractions was studied in twenty-five nulliparae at term. Uterine activity was found to decrease during the first 30 minutes following epidural block. In the time interval 30 to 40 minutes after epidural block uterine activity increased again and attained the same level as during the last 10 minutes before analgesia. The frequency of uterine contractions did not decrease after the block. The lower levels of uterine contractility were due only to a lower amplitude of the contractions. The regularizing effect of epidural analgesia on incoordinate uterine action was noted. The recording of fetal heart rate in the time interval studied revealed no pathological findings. Mode of delivery, mean labour duration and Apgar scores after epidural block were comparable with earlier studies of a larger patient population. This study suggest that epidural analgesia does not induce any important changes in fetal heart rate but temporarily decreases uterine activity. 相似文献
26.
Endotoxin signal transduction in macrophages 总被引:1,自引:0,他引:1
Through its action on macrophages, bacterial lipopolysaccharide (LPS) or endotoxin can trigger responses that are protective or injurious to the host. This review examines the effects of LPS on macrophages by following events from the cell surface to the nucleus. The involvement of protein tyrosine kinases, mitogen-activated protein kinases, protein kinase C, G proteins, protein kinase A, ceramide-activated protein kinase, and microtubules in this process are reviewed. At the nuclear level, rel, C/EBP, Ets, Egr, fos, and jun family members have been implicated in activation of LPS-inducible gene expression. 相似文献
27.
F Pagès M Ragueneau S Klasen M Battifora D Couez R Sweet A Truneh SG Ward D Olive 《Canadian Metallurgical Quarterly》1996,271(16):9403-9409
Through the interaction with its ligands, CD80/B7-1 and CD86/B7-2 or B70, the human CD28 molecule plays a major functional role as a costimulator of T cells along with the CD3-TcR complex. We and others have previously reported that phosphatidylinositol 3-kinase inducibly associates with CD28. This association is mediated by the SH2 domains of the p85 adaptor subunit interacting with a cytoplasmic YMNM consensus motif present in CD28 at position 173-176. Disruption of this binding site by site-directed mutagenesis abolishes CD28-induced activation events in a murine T-cell hybridoma transfected with human CD28 gene. Here we show that the last 10 residues of the intracytoplasmic domain of CD28 (residues 193-202) are required for its costimulatory function. These residues are involved in interleukin-2 secretion, p85 binding, and CD28-associated phosphatidylinositol 3-kinase activity. In contrast, the CD28/CD8O interaction is unaffected by this deletion, as is the induction of other second messengers such as the rise in intracellular calcium and tyrosine phosphorylation of CD28-specific substrates. Furthermore, we also demonstrate that, within these residues, the tyrosine at position 200 is involved in p85 binding, probably together with the short proline-rich motif present between residues 190 and 194 (PYAPP). 相似文献
28.
The studies of the eradication of barley mildew due to Erysiphe graminis Mérat with alkyldinitrophenols reported earlier1 were continued. The degree of eradication was highest with 4-(C9 α-branched alkyl)-2,6-dinitrophenols. 4-Alkyl-2,6-dinitrophenols containing a heptyl or higher alkyl branch were significantly less active, and compounds containing the C12 or C13 alkyls were not active since the most compact of the C12 α-branched alkyls is 1-pentylheptyl. 2-(1-Methylheptyl)- and 2-(1-propylpentyl)-4,6-dinitrophenols had high activity, but their esters showed reduced activity. Esterification of 4-(α-branched alkyl)-2,6-dinitrophenols to methyl carbonates did not affect the activity shown by the compounds, but when certain 4-C10 and C11 alkyl-2,6-dinitrophenols were esterified to ethyl carbonates the activity of the products was reduced. Also activity was diminished by conversion of some 4-C9 and C10 alkyl-2,6-dinitrophenols to crotonates. Whereas the methyl- and ethyl- carbonates of 4-(1-ethylhexyl)-2,6-dinitrophenol gave consistently high degrees of eradication of barley mildew, the performance of the crotonate of this phenol was not consistent. Lower aliphatic esters of the active C8-alkyl phenols were themselves active. Esterification of 4-(1-ethylhexyl)-2,6-dinitrophenol to the benzoate, isopropyl carbonate or S-methyl thiolocarbonate gave compounds with substantially reduced activity. 2-t-Butyl-4,6-dinitrophenyl or 4-t-butyl- or t-octyl-2,6-dinitrophenyl esters gave little or no significant eradication. 相似文献
29.
The use of optically isolated layers within a complex three-dimensional model permits a photoelastic analysis in their planes at room temperatures. A programme was undertaken to determine experimentally the state of stress in, and the structural behaviour of a portion of the aft bulkhead of an Fill aircraft in order to improve the fatigue life of the component. Information obtained about its behaviour under load clearly indicates the usefulness of this technique as a design tool; its general advantages and disadvantages are discussed by comparison with the stress freezing and slicing technique. 相似文献
30.
JL González CJ Russo D Goldowitz HO Sweet MT Davisson CA Walsh 《Canadian Metallurgical Quarterly》1997,17(23):9204-9211
The reeler mutation in mice produces an especially well characterized disorder, with systematically abnormal migration of cerebral cortical neurons. The reeler gene encodes a large protein, termed Reelin, that in the cortex is synthesized and secreted exclusively in the Cajal-Retzius neurons of the cortical marginal zone (D'Arcangelo et al., 1995). In reeler mutant mice, loss of Reelin protein is associated with a systematic loss of the normal, "inside-out" sequence of neurogenesis in the cortex: neurons are formed in the normal sequence but become localized in the cortex in a somewhat inverted, although relatively disorganized "outside-in" pattern. Here we show that the scrambler mutant mouse exhibits a loss of lamination in the cortex and hippocampus that is indistinguishable from that seen in the reeler mouse. We use BrdU birthdating studies to show that scrambler cortex shows a somewhat inverted "outside-in" sequence of birthdates for cortical neurons that is similar to that previously described in reeler cortex. Finally, we perform staining with the CR-50 monoclonal antibody (Ogawa et al., 1995), which recognizes the Reelin protein (D'Arcangelo et al., 1997). We show that Reelin immunoreactivity is present in the scrambler cortex in a normal pattern, suggesting that Reelin is synthesized and released normally. Our data suggest that scrambler is a mutation in the same gene pathway as the reeler gene (Relnrl) and is most likely downstream of Relnrl. 相似文献