Adolescents' mobility histories and present social adjustment     

Bradley C. Norford  Frederic J. Medway 《Psychology in the schools》2002,39(1):51-62

This study compared three groups of high school students: frequent movers (6 to 13 relocations), moderate movers (3 to 5 relocations), and nonmovers on depression, appraised social support, and participation in extracurricular activities. The sample was examined further according to the primary reason for relocation, the timing (before or after the seventh grade), and whether student shyness, socioeconomic status (SES), and family cohesion influenced any potential effects. Despite methodological improvements over past research including the exclusion of students who recently moved or reported other current stressors, few significant effects were obtained. Findings did reveal that students whose families relocated because of divorce and those who experienced early life relocations had lower levels of participation in extracurricular activities. Students reported less negative effects of relocation than did their mothers. Further, mothers' negative attitudes toward relocation were significantly correlated with student depression. It is concluded that there is little current or prior research evidence that high rates of social mobility are associated with long‐term social adjustment problems for adolescents. © 2002 John Wiley & Sons, Inc.  相似文献   

Fitness, Probability and the Principles of Natural Selection   总被引：4，自引：0，他引：4  

Bouchard  Frederic; Rosenberg  Alex 《The British journal for the philosophy of science》2004,55(4):693-712

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Aerodynamic drag in cycling: methods of assessment     

Pierre Debraux  Frederic Grappe  Aneliya V. Manolova  William Bertucci 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):197-218

When cycling on level ground at a speed greater than 14 m/s, aerodynamic drag is the most important resistive force. About 90% of the total mechanical power output is necessary to overcome it. Aerodynamic drag is mainly affected by the effective frontal area which is the product of the projected frontal area and the coefficient of drag. The effective frontal area represents the position of the cyclist on the bicycle and the aerodynamics of the cyclist-bicycle system in this position. In order to optimise performance, estimation of these parameters is necessary. The aim of this study is to describe and comment on the methods used during the last 30 years for the evaluation of the effective frontal area and the projected frontal area in cycling, in both laboratory and actual conditions. Most of the field methods are not expensive and can be realised with few materials, providing valid results in comparison with the reference method in aerodynamics, the wind tunnel. Finally, knowledge of these parameters can be useful in practice or to create theoretical models of cycling performance.  相似文献   

Business process management capabilities in local governments: A multi-method study     

Bjoern Niehaves  Ralf Plattfaut  Joerg Becker 《Government Information Quarterly》2013

Business Process Management (BPM) is a topic of greatest relevance to government innovation. While the concept originally stems from the private sector, public sector organizations have established BPM capabilities and are in the move of developing these further. Despite the importance of the phenomenon, literature does however not yet provide a comprehensive picture of BPM capabilities in governments. In this paper, we thus examine BPM capabilities on the local government level by means of an intertwined quantitative survey and (representative) qualitative in-depth case study. We identify a set of BPM challenges and reflect on the power of prevalent BPM capability assessment and development models, mostly maturity models, to provide good guidance. We suggest taking into account organizational positions in order to overcome the significant shortcoming of the ‘maturity’ concept, especially the focus on convergence towards an “ideal” state. Thus, we argue for developmental models following divergence theories. Implications for practice and potentially fruitful avenues for future research are discussed in the light of our findings.  相似文献   

Microarray of non-connected gold pads used as high density electric traps for parallelized pairing and fusion of cells     

Feriel S. Hamdi  Olivier Fran?ais  Frederic Subra  Elisabeth Dufour-Gergam  Bruno Le Pioufle 《Biomicrofluidics》2013,7(4)

Cell fusion consists of inducing the formation of a hybridoma cell containing the genetic properties of the progenitor cells. Such an operation is usually performed chemically or electrically. The latter method, named electrofusion, is considered as having a strong potential, due to its efficiency and non-toxicity, but deserves further investigations prior to being applicable for key applications like antibody production and cancer immunotherapy. Indeed, to envision such applications, a high amount of hybrid cells is needed. In this context, we present in this paper a device for massive cell pairing and electrofusion, using a microarray of non-connected conductive pads. The electrofusion chamber––or channel––exposes cells to an inhomogeneous electric field, caused by the pads array, enabling the trapping and pairing of cells with dielectrophoresis (DEP) forces prior to electrofusion. Compared to a mechanical trapping, such electric trapping is fully reversible (on/off handling). The DEP force is contactless and thus eases the release of the produced hybridoma. Moreover, the absence of wire connections on the pads permits the high density trapping and electrofusion of cells. In this paper, the electric field mapping, the effect of metallic pads thickness, and the transmembrane potential of cells are studied based on a numerical model to optimize the device. Electric calculations and experiments were conducted to evaluate the trapping force. The structure was finally validated for cell pairing and electrofusion of arrays of cells. We believe that our approach of fully electric trapping with a simple structure is a promising method for massive production of electrofused hybridoma.  相似文献   

Recent advances in machine learning for signal analysis and processing     

Anton Kummert  Joerg Velten 《Journal of The Franklin Institute》2018,355(4):1513-1516

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School climate and teacher beliefs in a school effectively serving poor South Carolina (USA) African-American students: A case study     

Kimberly E. Brown  Frederic J. Medway 《Teaching and Teacher Education》2007

This study examined the roles of school climate, teacher expectations, and instructional practices in one elementary school in South Carolina (USA) that produced effective achievement outcomes with poor and minority students. Survey data, teacher interviews, and classroom videotaping was used to identify school characteristics and instructional behaviors of six teachers nominated by colleagues as exemplary. The school was characterized by an emphasis on high student expectations, school staff cohesiveness, engaging instruction, high parent involvement, and multicultural instruction integrated with curriculum. The practices identified are consistent with literature on effective American schools; and the practices are key aspects of the sound instruction of poor and minority children. Teachers stated that teacher education programs did not prepare them to teach these students and that they had to learn this on the job.  相似文献   

Relative age effects in a cognitive task: A case study of youth chess     

Werner F. Helsen  Joseph Baker  Joerg Schorer  Christina Steingröver  Nick Wattie  Janet L. Starkes 《High Ability Studies》2016,27(2):211-221

The relative age effect (RAE) has been demonstrated in many youth and professional sports. In this study, we hypothesized that there would also be a RAE among youth chess players who are typically involved in a complex cognitive task without significant physical requirements. While typical RAEs have been observed in adult chess players, in this paper we wanted to focus primarily on youth chess players. In addition, we also examined RAEs in both participation rates and performance levels in a national chess championship. Therefore, the RAE was examined in a complex cognitive task that has no significant physical requirements, more specifically among youth chess players. Data were analyzed (1) for all registered Belgian youth chess players over a 5-year period (2009–2013) and (2) for participants of the Belgian youth championship 2013. Results indicated an overall RAE among all Belgian youth chess players over the last 5 years. The likelihood of participation was significantly greater for players born in the first birth-date quartile (χ² = 10.21, p < .05; r = ?.77, p < .01; w = .07) and the likelihood of participation decreased when youth chess players were born in the last quartile of the year. These effects were most prominent in the under-8 and under-10 year olds. There also appeared to be a performance-related RAE. Kolmogorov–Smirnov tests (p < .05) showed that players born in the first months of the selection year were significantly more often in the top 10 players for each age level of the Belgian Youth Championship 2013.  相似文献   

Book Review: Staying Legal: A Guide to Issues and Practice for Users and Publishers of Electronic Resources     

Marc Frederic Schaefer 《媒体管理杂志》2013,15(1-2):91-93

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The half-tone trichromatic process     

Frederic E. Ives 《Journal of The Franklin Institute》1902,153(1):43-50

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