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201.
Early in development, children explore and combine objects in increasingly complex ways. One manual skill, object construction, represents a major shift in how objects are explored relative to other objects. Despite recent connections with cognitive functioning such as spatial skills, the development of object construction ability has rarely been studied and its trajectory has not been adequately described. The purpose of this study was to describe the development of three types of object construction (stacking, nesting, and affixing) across 5 monthly infant visits and 7 monthly toddler visits using a longitudinal design and a large sample size. Infants (10–14 months, n = 131) and toddlers drawn from the infant sample (18–24 months, n = 65) were given sets of age‐appropriate toys each of which elicited at least one type of constructive play. We described success at different construction tasks and identified trends for construction skill for infant and toddler development using multilevel modeling. We found that each of the three construction actions developed in unique ways across the 10‐ to 24‐month period. Infant construction skill predicted the development of toddler skill, but toddler construction skill diverged from infant trajectories. We discuss the role of combination strategies in the development of object construction skill and how object construction could be related to other domains of development. 相似文献
202.
The primary objective of a multi-regional clinical trial is to investigate the overall efficacy of the drug across regions and evaluate the possibility of applying the overall trial result to some specific region. A challenge arises when there is not enough regional sample size. We focus on the problem of evaluating applicability of a drug to a specific region of interest under the criterion of preserving a certain proportion of the overall treatment effect in the region. We propose a variant of James-Stein shrinkage estimator in the empirical Bayes context for the region-specific treatment effect. The estimator has the features of accommodating the between-region variation and finiteness correction of bias. We also propose a truncated version of the proposed shrinkage estimator to further protect risk in the presence of extreme value of regional treatment effect. Based on the proposed estimator, we provide the consistency assessment criterion and sample size calculation for the region of interest. Simulations are conducted to demonstrate the performance of the proposed estimators in comparison with some existing methods. A hypothetical example is presented to illustrate the application of the proposed method. 相似文献
203.
This paper concerns the forecasting of seasonal intraday time series that exhibit repeating intraweek and intraday cycles. A recently proposed exponential smoothing method involves smoothing a different intraday cycle for each distinct type of day of the week. Similar days are allocated identical intraday cycles. A limitation is that the method allows only whole days to be treated as identical. We introduce a new exponential smoothing formulation that allows parts of different days of the week to be treated as identical. The result is a method that involves the smoothing and initialisation of fewer terms. We evaluate forecasting up to a day ahead using two empirical studies. For electricity load data, the new method compares well with a range of alternatives. The second study involves a series of arrivals at a call centre that is open for a shorter duration at the weekends than on weekdays. Among the variety of methods considered, the new method is the only one that can model in a satisfactory way in this situation, where the number of periods on each day of the week is not the same. 相似文献
204.
Anke W. Blöte Caroline L. Bokhorst Anne C. Miers P. Michiel Westenberg 《Journal of research on adolescence》2012,22(1):123-134
This study addressed the role of actual and perceived similarity in peer rejection of socially anxious adolescents. Videotapes of 20 high and 20 low socially anxious adolescents (13–17 years old) giving a speech were rated by groups of unfamiliar peers with regard to perceived similarity and desire for future interaction (lower scores indicating rejection). Actual similarity between speakers and observers regarding social anxiety and gender was also taken into account. Findings showed that high socially anxious students were more rejected and that perceived but not actual similarity between peer observers and speakers (partly) mediated rejection. 相似文献
205.
The amount of radon in natural gas varies with its source. Little has been published about the radon from shale gas to date, making estimates of its impact on radon‐induced lung cancer speculative. We measured radon in natural gas pipelines carrying gas from the Marcellus Shale in Pennsylvania and West Virginia. Radon concentrations ranged from 1,520 to 2,750 Bq/m3 (41–74 pCi/L), and the throughput‐weighted average was 1,983 Bq/m3 (54 pCi/L). Potential radon exposure due to the use of Marcellus Shale gas for cooking and space heating using vent‐free heaters or gas ranges in northeastern U.S. homes and apartments was assessed. Though the measured radon concentrations are higher than what has been previously reported, it is unlikely that exposure from natural gas cooking would exceed 1.2 Bq/m3 (<1% of the U.S. Environmental Protection Agency's action level). Using worst‐case assumptions, we estimate the excess lifetime (70 years) lung cancer risk associated with cooking to be 1.8×10?4 (interval spanning 95% of simulation results: 8.5×10?5, 3.4×10?4). The risk profile for supplemental heating with unvented gas appliances is similar. Individuals using unvented gas appliances to provide primary heating may face lifetime risks as high as 3.9×10?3. Under current housing stock and gas consumption assumptions, expected levels of residential radon exposure due to unvented combustion of Marcellus Shale natural gas in the Northeast United States do not result in a detectable change in the lung cancer death rates. 相似文献
206.
Kyle W. Knight 《Population and environment》2014,36(1):32-47
This study assesses the degree to which the relationship between the environmental demands of countries (measured as ecological footprint per capita) and well-being (measured as life expectancy) has changed over the last several decades (1961–2007) and whether the nature and extent of these changes differ between developed and less-developed countries. Pooled ordinary least squares regression results indicate that decoupling has occurred among developed countries, where the relationship between ecological footprint and life expectancy weakened substantially over time, becoming negative in later years. In less-developed countries, the relationship has intensified substantially, with the effect of ecological footprint on life expectancy becoming stronger over time. Fixed-effects regression results provide similar results for developed countries but indicate slight decoupling between increases in ecological footprint and life expectancy among less-developed countries. The implications of these results are discussed in the context of contraction and convergence approaches to sustainability. 相似文献
207.
Adolescent Personality as Risk and Resiliency in the Testosterone–Externalizing Association
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Kathleen W. Reardon Kathrin Herzhoff Jennifer L. Tackett 《Journal of research on adolescence》2016,26(3):390-402
Previous investigations of testosterone and externalizing behavior have provided mixed findings. We tested the hypothesis that self‐regulatory personality moderates the testosterone–externalizing behavior association in adolescence. Parents reported on their 13‐ to 18‐year‐old (N = 106, Mage = 16.01, SD = 1.29) children's personalities and psychopathology. Testosterone was measured via drool samples. As hypothesized, personality moderated the testosterone–externalizing behavior association. High testosterone predicted higher levels of externalizing behaviors, but only for adolescents low in Agreeableness and Conscientiousness. Also, personality acted as a resiliency factor: high levels of Conscientiousness, in the presence of high testosterone, predicted lower levels of rule breaking. Results highlight how endogenous factors, such as personality, may interact with testosterone, and emphasize the relevance of including personality moderators in future research. 相似文献
208.
George W. Leeson 《Journal of Population Research》2017,34(1):1-15
The world is ageing both at an individual and a population level, and population ageing is truly a global phenomenon. Life expectancies at birth have increased at the global level from 47 years in the mid-20th century to around 70 years today, and are expected to rise to 76 years by the mid-21st century. The proportion of the world’s population aged 60 years and over has increased from 8 % in the mid-20th century to 12 %, and by 2050 it is expected to reach 21 %. The emergence of large numbers of centenarians has accompanied this development. This paper outlines this emergence historically and the likely growth in the number of centenarians in the 21st century, in particular in England and Wales, analysing mortality trends since 1840 and the rise in the number of centenarians in the 20th and 21st centuries. The number of centenarians in England and Wales increased from around 160 in 1922 to almost 12,500 by 2012, but if mortality at all ages had remained constant from 1912 to 2012, then by 2012 the number of centenarians would only have been around 720. By 2100, the number of centenarians is expected to reach around 1.4 million, but if future mortality at all ages were to remain constant, then by 2100 the number of centenarians would be around 78,000. However, if predicted mortality for those aged 55 years and over was to decrease by an additional 5 % every 5 years until 2100, then the number of centenarians in England and Wales would reach around 1.8 million by the end of the century. 相似文献
209.
210.