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41.
In seven experiments, 2 squirrel monkeys were given choices between arrays of food that varied in the quantity offered. In Experiments 1-5, the monkeys were offered choices between quantities of the same food that varied in a 2:1 ratio. The squirrel monkeys failed to show the temporal myopia effect or a decrease in preference for the larger quantity as the absolute number of food items offered increased. Even when given choices of 8 versus 16 peanuts and 10 versus 20 peanuts, both monkeys significantly preferred the larger quantity. An examination of the monkeys' rates of consumption indicated that 20 peanuts were consumed over a 1- to 2-h period, with eating bouts separated by periods of nonconsumption. In Experiments 6A, 6B, and 7, food was either pilfered or replenished 15 min after an initial choice, so that choice of the smaller quantity led to more total food in the long run. These manipulations caused both monkeys to reduce choice of the larger quantity, relative to baseline choice. The results suggest that squirrel monkeys anticipated the future consequences of their choices.  相似文献   
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Do young boys and girls understand what leads to academic success (e.g., talent, effort, good teaching, luck) in the same way? Do young girls and boys have equivalent perceptions of their academic competence? Are these beliefs engendered in the same way across sociocultural contexts? In a cross-cultural study of over 3,000 children in grades 2 to 6, ages 7.2 to 13.6, we discovered that boys and girls around the world have very similar ideas about what generally leads to academic success. Moreover, in the few contexts where boys' and girls' academic performances were equal, their beliefs were also equal. However, when girls outperformed boys, their beliefs in their own talent were no greater than boys' beliefs, even though they did have stronger beliefs than boys in other facets of their achievement potential (e.g., putting forth effort, being lucky, getting their teacher's help). Our findings support the generally close correspondence between children's achievement and their competence-related beliefs, with the exception that young girls appear to specifically discount their talent. The effects held regardless of the children's achievement, intelligence, or age (approximately 8 to 13 years). Girls were more biased in some contexts than in others, however, suggesting that competence-related biases are rooted in culture-specific aspects of school settings.  相似文献   
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研究了火焰原子吸收光谱法测定杞菊地黄丸中铜含量的方法,样品采用HNO3:HClO4(4:1)消化体系,方法简便、快速、省时.具有良好的精密度和准确度.精密度为7.45%,检出限为0.0059μg/ml,回收率达到92.3~110%.  相似文献   
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Relations between self-reported parental reactions to children's negative emotions (PNRs) and children's socially appropriate/problem behavior and negative emotionality were examined longitudinally. Evidence was consistent with the conclusion that relations between children's externalizing (but not internalizing) emotion and parental punitive reactions to children's negative emotions are bidirectional. Reports of PNRs generally were correlated with low quality of social functioning. In structural models, mother-reported problem behavior at ages 10-12 was at least marginally predicted from mother-reported problem behavior, children's regulation, and parental punitive or distress reactions. Moreover, parental distress and punitive reactions at ages 6-8 predicted reports of children's regulation at ages 8-10, and regulation predicted parental punitive reactions at ages 10-12. Father reports of problem behavior at ages 10-12 were predicted by earlier problem behavior and parental distress or punitive reactions; some of the relations between regulation and parental reactions were similar to those in the models for mother-reported problem behavior. Parental perceptions of their reactions were substantially correlated over 6 years. Some nonsupportive reactions declined in the early to mid-school years, but all increased into late childhood/early adolescence.  相似文献   
45.
We investigated the kinds of instructional and assessment accommodations students with disabilities receive, and the extent to which instructional accommodations match assessment accommodations. Most students who had IEPs in specific content areas received instructional accommodations in those areas, and there were no differences by disability type. We provide data on the specific types of accommodations used. Overall, students' assessment accommodations matched their instructional accommodations, though many students received testing accommodations that had not been received in instruction. Implications are discussed for IEP teams who make decisions about instructional and assessment accommodations.  相似文献   
46.
织物风格特征是由织物组织结构和纱的特性决定的,新型纱线结构的不断出现和发展对织物性能和质量提出了更高的要求。研究表明:通过改变纺纱工艺可以获得不同的纱线结构,从而改变织物的风格特征。DREF-Ⅲ型摩擦纺包芯纱具有典型的皮芯结构,可以是双组分也可以是多组分,而且组分的不同会对织物性能产生不同的影响,纱的性能也会由于芯皮之间压力、摩擦力大小的不同而改变。以前的研究主要集中在包芯纱的拉伸性能上,而对空心纱几乎没有什么新的研究和讨论。  相似文献   
47.
原子核的秘密的揭露,使人类掌握了新的無穷尽的能源。第一座原子能电站在苏联的建立,为將这个能源实际利用于工業和农業的和平目的,奠定了基础。原子技术的發展,开辟了把放射性同位素应用到各种全然不同的科学技术部門中去的广闊的可能性。人工取得放射性同位素的方法之一,是在原子核反应堆中用中子来照射。比如,用中子照射普通的天然的磷的时候,部分的磷原子核就和中子結合而变成磷的放射性同位素(磷-32)的原子核。当放射性磷的核衰变的时候,核中的一个中子轉化成質子,同时放射出一个β粒子(帶陰电的电子)。衰变是按照这个方式發生  相似文献   
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