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In this study, the authors examined the extent to which children’s self-regulation upon kindergarten entrance and classroom quality in kindergarten contributed to children’s adaptive classroom behavior. Children’s self-regulation was assessed using a direct assessment upon entrance into kindergarten. Classroom quality was measured on the basis of multiple classroom observations during the kindergarten year. Children’s adaptive classroom behavior in kindergarten was assessed through teacher report and classroom observations: Teachers rated children’s cognitive and behavioral self-control and work habits during the spring of the kindergarten year; observers rated children’s engagement and measured off-task behavior at 2-month intervals from November to May. Hierarchical linear models revealed that children’s self-regulation upon school entry in a direct assessment related to teachers’ report of behavioral self-control, cognitive self-control, and work habits in the spring of the kindergarten year. Classroom quality, particularly teachers’ effective classroom management, was linked to children’s greater behavioral and cognitive self-control, children’s higher behavioral engagement, and less time spent off-task in the classroom. Classroom quality did not moderate the relation between children’s self-regulation upon school entry and children’s adaptive classroom behaviors in kindergarten. The discussion considers the implications of classroom management for supporting children’s early development of behavioral skills that are important in school settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

3.
 在冷轧可逆轧制的不同道次,与板形检测辊接触的带钢温度差异显著,使得检测辊的温度场和应力场不稳定。运用有限元软件ANSYS建立了板形检测辊的热力耦合模型,分析了轧制过程中板形检测辊的瞬态温度场和应力场。结果表明,轧制开始后接触带钢的热量由辊体外表面向内表面逐渐传递,传感器正上方的辊体外表面温度上升最快,并在1940s达到温度最大值135℃;骨架顶部与辊体内孔面的接触热阻使传感器的温度上升较慢,骨架顶部在 2280s达到温度最大值134℃;板形检测辊的最大应力发生在与骨架顶部接触的辊体内孔面上,其在940s达到最大值301MPa,满足材料强度的许用应力要求。通过模拟分析结果与现场实测数据对比,证明了有限元分析模型的正确性。  相似文献   

4.
The first modern metal cantilever bridge in the United States, using erection methods that were to be utilized in most future cantilever bridges, was by C. C. Schneider across the Niagara Gorge in 1883. The Niagara, saw in order, John Roebling’s Railroad Suspension Bridge, Samuel Keefer’s Honeymoon Suspension Bridge, Edward Serrell’s Lewiston-Queenston Suspension Bridge, Schneider’s cantilever, Leffert Buck’s arch bridge at the falls as well as Buck’s arch built under Roebling’s suspension bridge. Schneider’s bridge had a useful life of over 40 years during a period when rolling stock on the railroads was increasing rapidly. The speed of erection of a new style bridge coupled with its performance makes it one of the most innovative and significant bridges built in the world at the time.  相似文献   

5.
Faithfully following the tradition of Bowlby’s theoretical framework, until recently research in developmental psychology has more often confirmed the importance of attachment to mother than to father in their children’s development. Based on this statement, Paquette (2004) proposed a different theoretical model to account for the father’s specific role in children’s development. The purpose of this review of the literature is to examine results of studies including measures of attachment to mother and to father and to answer the questions raised by different theoretical models accounting for the organization of children’s attachment relationships, that is to say hierarchy in children’s attachment to mother and to father, correspondence between the quality of these two relationships and their influence on children’s development. Whether the attachment theoretical framework seems to partially account for the specificity and the complementarity of parental roles, results of the studies reviewed in this article underline the necessity to operationalize the activation dimension of attachment relationships (Paquette, 2004) in order to better understand how children’s attachment relationships to parents do develop and how they do organize themselves to influence children’s development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

6.
Ten natural bloom samples of cyanobacteria from the Danish lakes Knud s? (5), Ravn s? (4), and Salten Langs? (1) collected during 1993-1995 were assayed for toxicity by mouse bioassay, for acetylcholinesterase inhibiting activity by a colorimetric method, and for microcystins by enzyme-linked immunosorbent assay. In the mouse bioassay, seven samples were neurotoxic, two were non-toxic and one gave a protracted toxic response. One of the non-toxic and the single protracted toxic sample both contained anticholinesterase activity equivalent to 4 micrograms anatoxin-a(s) g-1. The neurotoxic samples contained equivalents to 20-3300 micrograms anatoxin-a(s) g-1. The highest anticholinesterase activities (equivalent to 2300 and 3300 micrograms anatoxin-a(s) g-1, respectively) were found in samples collected from Lake Knud s? in connection with bird-kills in 1993 and 1994. Small amounts of microcystins (0.1-0.9 microgram g-1) were detected in all samples but one. All Lake Knud s? and Lake Ravn s? samples were dominated by Anabaena lemmermannii, and the Lake Salten Langs? sample by several species of Anabaena. Gel filtration profiles indicated similarity between the toxic component from the Lake Knud s? 1994 bloom with registered bird-kills and anatoxin-a(s) isolated from Anabaena flos-aquae NRC-525-17. Anticholinesterase-producing cultures of A. lemmermannii were isolated from the Lake Knud s? 1993 bloom. These laboratory cultures produced anatoxin-a(s) equivalents of 29-743 micrograms g-1. Other cultures of A. lemmermannii isolated from Lake Knud s? and Lake Ravn s? were hepatotoxic or non-toxic. Dead birds collected from Lake Knud s? during the neurotoxic 1993 Anabaena bloom possibly died from cyanobacterial toxicosis. The stomach contents contained colonies and single trichomes of Anabaena, and anticholinesterase activities equivalent to 2.1-89.7 micrograms anatoxin-a(s) kg-1 body weight and microcystins (53-95 ng kg-1) were also detected.  相似文献   

7.
BACKGROUND: Mosaicism of the Helicobacter pylori vac A gene comprises two families of allelic variations of the signal sequence region (s1, s2) and of the mid-region (m1, m2). Initial studies suggested that peptic ulcer disease correlated with the s1 subtype of vac A. We compared the prevalence of various vac A genotypes of H. pylori isolates obtained from duodenal ulcer (DU) patients and subjects with simple gastritis. Those isolates with s1 type were further examined to determine whether the specific vac A s1 (s1a versus s1b) genotype enabled prediction of gastroduodenal disease. METHODS: H. pylori isolates were obtained from 38 patients with endoscopically documented DU and 39 individuals with asymptomatic H. pylori gastritis from Houston, Texas. The vac A genotype of each isolate was determined by polymerase chain reaction (PCR) amplification of genomic DNA for specific regions of the vac A gene. Those isolates with s1 vac A subtype were further examined to determine whether they had s1a or s1b mosaicism. RESULTS: There was no difference in frequency of the s1 genotype of isolates obtained from patients with duodenal ulcer or asymptomatic H. pylori gastritis in this sample (84% versus 79%, respectively; P = 0.77). The s1/m1 vac A genotype was detected in isolates from 16 duodenal ulcer patients versus 15 with H. pylori gastritis (P = 0.82). Detailed analysis of the s1 region failed to show a correlation of either s1a or s1b with duodenal ulcer. Both s1a and s1b genotypes were detected in 24 strains, and both m1 and m2 mid-gene PCR amplicons were seen in 16 strains. CONCLUSIONS: We were unable to use H. pylori vac A genotyping to predict type of gastroduodenal disease in our patient sample. This failure to confirm an association of vac A genotype and duodenal ulcer disease differs from samples from other regions. This most likely represents an example of differences in H. pylori strains infecting host populations in different geographic regions. This study confirms the importance of establishing statistical associations with isolates from widely separate geographic regions before concluding that disease-related associations exist.  相似文献   

8.
The delayed type hypersensitivity (DTH) response to xenogeneic hepatocytes (HCs) was investigated in mice received subcutaneous (s.c.), intrasplenic (i.s.), or intravenous (i.v.) transplantation of rat HCs. The DTH response in mice preimmunized i.s. or i.v. with rat HCs (1 x 10(6) cells) was significantly lower than that in mice preimmunized s.c. with the same doses of rat HCs. Co-transfer of spleen cells from i.s. immunized mice with spleen cells from s.c. immunized mice to naive recipient mice did not suppress the DTH response induced by transfer of spleen cells from s.c. immunized mice. On the other hand, co-transfer of spleen cells from i.v. immunized mice with spleen cells from s.c. immunized mice suppressed the DTH response to rat HCs in recipients. Furthermore, the levels of DTH responses in recipients transferred with spleen cells from mice sensitized i.s. or i.v. with rat HCs, immunized s.c. with rat HCs 6 hr after transfer, and challenged with rat HCs 7 days later was almost similar to those in recipients transferred with spleen cells from s.c. immunized mice. These results suggest that antigen-specific suppression of DTH responses to rat HCs in mice is associated with the presence of suppressive spleen cells induced by i.s. or i.v. immunization with rat HCs.  相似文献   

9.
Selected pathological sera gave three molecular species of C1s protein on crossed immunoelectrophoresis in the presence of calcium. C1s precipitates were obtained at the origin and in the beta1 and alpha2 regions. 12 normal sera gave C1s protein peaks at the origin and in alpha2 position. One of the normal sera also contained a small amount of the beta1 C1s protein. The C1s protein at the origin represented macromolecular C1. The alpha2 peak was a complex composed of C1 IA, C1s and C1r proteins. This complex was preformed in serum and did not show C4 cleaving activity. The molecular species in the beta1 region was shown to be a calcium-dependent complex of C1r and C1s, probably in proenzyme form. the C1r-C1s complex formed macromolecular C1 on addition of purified C1q to serum. During electrophoresis activation of C1 subcomponents was initiated by a mechanism involving CIr with generation of CIs activity in eluted fractions corresponding to the position of macromolecular C1 as well as in the beta region. The significance of beta1 C1s complexes or of alpha2 C1s complexes in normal and pathological sera was discussed.  相似文献   

10.
It was the aim of the present study to evaluate whether, in physiological cardiac tissue, long and short splice variants of G(s)alpha (the alpha subunit of the stimulatory G-protein) differ in their susceptibility to guanine nucleotide-mediated activation. As a measure of G(s)alpha activation, we determined the proportion of G(s)alpha subunits which were released from the plasma membrane upon stimulation. Membrane preparations from heart ventricles of Wistar rats were incubated with increasing concentrations of the non-hydrolyzable GTP analogue guanylyl-imidodiphosphate (GppNHp, 0-100 micromol/L) in the absence or presence of the beta-adrenoceptor agonist isoprenaline (1 micromol/L). The 45 and 52 kDa forms of G(s)alpha (G(s)alpha-S and -L, respectively) were measured in the supernatant of the incubation mixture by immunoblotting and densitometry. The increase in cyclic AMP induced by GppNHp was measured in the same supernatant. In the absence of isoprenaline, GppNHp increased cyclic AMP formation and the concentration-dependent release of G(s)alpha-L (Friedman test, P < 0.05), whereas the amount of soluble G(s)alpha-S was not affected. After addition of isoprenaline, the redistribution of G(s)alpha-S into the soluble fraction could be stimulated by GppNHp in a concentration-dependent manner (P < 0.05). Kinetic experiments revealed that activation of G(s)alpha-S by GppNHp was rather slow, but could be markedly enhanced by isoprenaline. Thus, it is likely that the different susceptibilities of G(s)alpha-S and -L towards GppNHp reflects differences in the rate of spontaneous GDP release.  相似文献   

11.
含钒页岩浸出槽是钒页岩湿法提钒浸出段的主要操作单元,存在固相分布不均、槽底矿物易沉积等问题。通过数值模拟研究来对比分析搅拌桨叶双层同速以及异速方案下对搅拌浸出槽内固液两相流搅拌功率和效率的影响。结果表明,当搅拌桨叶双层同速由1.3 r/s改变至1.7 r/s时,死区由5.02 m3减少至2.03 m3,混匀时间由1 501 s降低至1 116 s,近自由液面平均速度也由0.32 m/s增大至0.56 m/s,因此搅拌桨转速选择1.7 r/s更为合适;搅拌桨叶双层异速可以得到与双层同速情况下基本一致的搅拌效果,当上层桨叶转速由1.5 r/s改变至1.7 r/s时,死区由2.95 m3减少至2.33 m3,混匀时间由1 261 s降低至1 146 s,近自由液面平均速度也由0.44 m/s增大至0.54 m/s。因此搅拌桨转速选择上层1.7 r/s、下层1.5 r/s能在保持较低的搅拌功率同时能得到较好的搅拌效率。  相似文献   

12.
Activation and depalmitoylation of Gs alpha   总被引:1,自引:0,他引:1  
[3H]palmitate attached to mutationally activated alpha s (alpha s-R201C) turns over rapidly, compared with palmitate linked to normal alpha s (t1/2 approximately 2 min versus 90 min); although alpha s-R201C (unlike normal alpha s) is predominantly found in the cytosol, [3H]palmitate is linked only to the membrane-bound pool of alpha s, normal or mutant. Similarly, activation of wild-type alpha s by isoproterenol, a beta-adrenoceptor agonist that also induces membrane-to-cytosol translocation of alpha s, dramatically accelerates depalmitoylation of alpha s. Thus, activation-induced removal of palmitate provides an explanation for activation-induced shifts of alpha s to the cytosol. Regulated palmitoylation cycles provide a potential general mechanism for controlling reversible changes in the cellular location and activity of a protein.  相似文献   

13.
湿法炼锑工艺中杂质砷的去除是影响产品质量的关键因素,文章在分析该工艺中砷流向的基础上,提出了去除控制的方法,并运用于生产实践,产品砷含量得以有效控制。  相似文献   

14.
This study focuses on relations between fathers’ behavior in family context and children’s adjustment, including the roles of paternal depressive symptoms, paternal marital conflict behaviors, paternal parenting, and children’s emotional security. Participants included 235 families with a six-year-old child, with families followed longitudinally each year for three years. In terms of fathers’ adjustment, paternal problem drinking was related to paternal negative marital conflict behaviors and decreased positive parenting, which was associated with children’s externalizing and internalizing problems. Fathers’ depressive symptoms were directly related with children’s internalizing problems. Children’s emotional security was an intervening variable in relations between father’s behavior in family context and children’s development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

15.
An equilibrium between free C1s and C1s bound in macromolecular C1 exists in human serum. This equilibrium can be utilized to incorporate radioiodinated C1s into serum C1. Human sera were incubated for 40 hr at 4 degrees C with 125I-C1s to allow the exchange between free and bound C1s to reach equilibrium. The C1 complex labeled in this manner was separated from the majority of serum proteins by centrifugation in linear 10 to 30% sucrose density gradients. The resulting fractions containing 125I-C1 can be used directly and conveniently in C1 activation assays that detect the cleavage of proenzyme C1s. Electrophoretic analysis on polyacrylamide gels showed the presence of only proenzyme 125I-C1s in serum C1, whether or not the applied labeled material contained 125I-C1s or other labeled proteins. The inability of C1 to incorporate C1s was shown to be the result of decreased stability of C1 upon activation.  相似文献   

16.
In the sensory preconditioning (spc) analogue to partial reinforcement, the proportion of stimulus (s) presentations that are followed by s2 is varied in the preconditioning phase. 32 experimentally naive male hooded rats received 1 of the following: 100, 50, or 25% pairings, or random presentations of tone and light, counterbalanced as s1 and s2 within groups, followed immediately by cer training to s2. Initial suppression of consummatory drinking to s1 was directly related, while resistance to extinction over 4 days of testing was inversely related to the percentage of pairings in preconditioning. Results are similar in pattern to those found in classical conditioning. (french summary) (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

17.
In order to study the regulation of the ribosomal protein S6 kinase, p70s6k, by G protein-coupled receptors, Rat-1 fibroblasts were stably transfected with two versions of the alpha2 adrenergic receptor. Stimulation of clone 1C cells, which express 3.5 pmol/mg of protein of the human alpha2C10 receptor, with the alpha2 agonist UK 14304 led to a transient increase in p70s6k activity. UK 14304 also activated p70s6k in a clone expressing the porcine alpha2A receptor (400 fmol/mg of protein). Lysophosphatidic acid (LPA), acting through endogenous G protein-coupled receptors, also activated p70s6k in alpha2 receptor-transfected and in nontransfected cells. Activation of p70s6k by both UK 14304 and LPA was accompanied by increased phosphorylation of the protein. Rapamycin completely blocked the activation of p70s6k by both agents. Activation of p70s6k by UK 14304 and by LPA, but not by platelet-derived growth factor (PDGF), was blocked by preincubation of cells with pertussis toxin. Wortmannin, a selective inhibitor of phosphoinositide (PI) 3-OH kinase, prevented activation of p70s6k by UK 14304, LPA, and PDGF. These data indicate that p70s6k is regulatable by Gi-coupled receptor agonists in a pertussis toxin-sensitive fashion in Rat-1 fibroblasts and that activation of p70s6k by such agents appears to involve an isoform of PI 3-kinase.  相似文献   

18.
This article celebrates the 50th anniversary of the introduction of John L. Holland’s (1959) theory of vocational personalities and work environments by describing the theory’s development and evolution, its instrumentation, and its current status. Hallmarks of Holland’s theory are its empirical testability and its user-friendliness. By constructing measures for operationalizing the theory’s constructs, Holland and his colleagues helped ensure that the theory could be implemented in practice on a widespread basis. Empirical data offer considerable support for the existence of Holland’s RIASEC types and their ordering among persons and environments. Although Holland’s congruence hypotheses have received empirical support, congruence appears to have modest predictive power. Mixed support exists for Holland’s hypotheses involving the secondary constructs of differentiation, consistency, and vocational identity. Evidence of the continued impact of Holland’s theory on the field of counseling psychology, particularly in the area of interest assessment, can be seen from its frequent implementation in practice and its use by scholars. Ideas for future research and practice using Holland’s theory are suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

19.
Long-term trends in the incidence, prognosis, and mortality of patients with ovarian cancer and borderline tumours in Norway were examined based on data from the population-based Cancer Registry of Norway. The incidence of ovarian cancer rose continuously from the mid-1950s to the mid-1980s. There was also an increasing trend in the incidence of borderline tumours from the early 1970s to the early 1990s. The prognosis for patients with ovarian cancer has improved since the 1950s. In 1989-93 the five-year relative survival rate was 37%. The prognosis for patients with borderline tumours was very favourable, with a five-year relative survival rate of 93% (1970-93). The mortality from ovarian cancer has been almost constant since the 1960s.  相似文献   

20.
详细介绍了丹江铝业公司技术改造情况和 114 .5kA预焙槽技术特点。针对我国铝工业现状以及自焙槽的改造 ,提出了丹江铝业公司改造中运用的技术对我国自焙槽技术改造的借鉴作用  相似文献   

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