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In the present study, we describe a participating student’s (Carol’s) distributive partitioning scheme and operations along with Steffe’s and his colleagues’ studies about children’s constructions of fraction knowledge as a particular model of mathematical learning. Analysis of Carol’s mathematical behaviors indicates that an operationally common mathematical behavior (distributive partitioning operation) was revealed in various mathematical problem situations such as fraction multiplication, fraction division, and multiplicative transformation between fractional quantities. It both provides a rationale for why becoming versed in one mathematical subject could facilitate working with another mathematical subject and also implies the necessity of describing and defining students’ mathematical behaviors from an operational view of knowledge, which might lead to building foundations of a substantial cognitive map for students’ mathematical development.  相似文献   
34.
The current study took a person-centered approach to examine the heterogeneity of changes in children’s emotions and persistence during a goal-blocking task and examined how different profiles of emotions and persistence related to children’s self-regulation. Children’s anger, sadness, and persistence were rated in a goal-blocking task in toddlerhood (T1; N = 140, 72 boys, Mage = 2.67 years, 90.7% White) and preschool (T2). Children’s self-regulation, specifically sustained attention and engagement, was assessed at T1, T2, and early school-age (T3) from 2005 to 2012. Growth mixture modeling revealed two classes of children at T1 and three classes at T2 with different patterns of anger, sadness, and persistence. Children’s classification at T2, but not T1, significantly predicted their sustained attention and engagement both concurrently and longitudinally.  相似文献   
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In this article visual technologies and their use in three reconstructions after an incident are linked with accountability issues. Conclusions are drawn on the relation between administration, the choice of technology to create and distribute visual occurrences, and society and how visualizations are used to frame accountability issues.  相似文献   
36.
This paper reports a method to control the fluid flow in paper-based microfluidic devices simply by pressing over the channel surface of paper, thereby decreasing the pore size and permeability of a non-woven polypropylene sheet. As a result, fluid resistance is increased in the pressed region and causes flow rate to decrease. We characterize the decrease of flow rate with respect to different amounts of pressure applied, and up to 740% decrease in flow velocity was achieved. In addition, we demonstrate flow rate control in a Y-shaped merging paper and sequential delivery of multiple color dyes in a three-branched paper. Furthermore, sequential delivery of multiple fluid samples is performed to demonstrate its application in multi-step colorimetric immunoassay, which shows a 4.3-fold signal increase via enhancement step.  相似文献   
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In this paper, we study to what extent a movie’s box-office receipts are affected by the temporal distribution of rival films. We propose a reduced-form empirical model to measure and test competition effects among films released close to each other in a standard regression framework. Such an analysis is appealing in terms of its policy implication and may provide guidance to distributors to decide on their releasing dates of their firms. We estimate this model using information on the films released in five countries: the USA, the United Kingdom, Germany, France and Spain. The geographical dimension of our data set permits us to control for unobserved heterogeneity among films released using panel data techniques, which allows us to evaluate the individual and specific effects of each film. Thus we deal with one of the most relevant features of the movie market, namely the presence of highly differentiated products.  相似文献   
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Responding to a survey requires cognitive abilities similar to those for any other linguistic task. We argue that, when faced with a cognitively challenging task, individuals respond by simplifying the task, declining it, or performing it poorly. Using the 2003 Program for International Student Assessment (PISA 2003) data sets, we document that the extent of construct differentiation in students’ mathematics learning strategies is strongly associated with their level of mathematics achievement. Likewise, the higher the level of mathematics achievement, the lower is the probability of a non-response to the mathematics learning strategy questions. Finally, the higher the students’ level of mathematics achievement, the more varied were their responses to the learning strategies items. These associations were examined across 40 participating countries.  相似文献   
39.
Simple as the outflow clock principle may seem for the measurement of time, its translation into an accurate clock raises formidable technical and conceptual problems. An attempt is made here to reconstruct the Egyptians' consciousness of these problems, and the success of their solutions.  相似文献   
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The present study examined the motivational correlates and achievement consequences of students’ help-seeking tendencies during sixth grade (N = 217). Students’ grades were collected from school records at the beginning and end of the school year. Midway through the year students reported on their academic self-efficacy and social demonstration goals; teachers reported on students’ help-seeking tendencies. First quarter grades and academic self-efficacy were positively related to adaptive help seeking and negatively related to avoidant help seeking. In addition, a social demonstration-approach goal was negatively related to adaptive help seeking. Help-seeking tendencies predicted 3rd quarter grades, controlling for 1st quarter grades.  相似文献   
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