The challenge of writing first reading books     

Cecilia Obrist 《Literacy》1981,15(3):32-41

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Hormonal responses to exercise after partial sleep deprivation and after a hypnotic drug-induced sleep     

Mougin F  Bourdin H  Simon-Rigaud ML  Nguyen NU  Kantelip JP  Davenne D 《Journal of sports sciences》2001,19(2):89-97

The aim of this study was to determine the hormonal responses, which are dependent on the sleep wake cycle, to strenuous physical exercise. Exercise was performed after different nocturnal regimens: (i) a baseline night preceded by a habituation night; (ii) two nights of partial sleep deprivation caused by a delayed bedtime or by an early awakening; and (iii) two nights of sleep after administration of either a hypnotic compound (10 mg zolpidem) or a placebo. Eight well-trained male endurance athletes with a maximal oxygen uptake of 63.5 +/- 3.8 ml x kg(-1) x min(-1) (mean value +/- s(x)) were selected on the basis of their sleeping habits and their physical training. Polygraphic recordings of EEG showed that both nights with partial sleep loss led to a decrease (P< 0.01) in stage 2 and rapid eye movement sleep. A delayed bedtime also led to a decrease (P < 0.05) in stage 1 sleep. Zolpidem had no effect on the different stages of sleep. During the afternoon after an experimental night, exercise was performed on a cycle ergometer. After a 10-min warm-up, the participants performed 30 min steady-state cycling at 75% VO(2-max) followed by a progressively increased workload until exhaustion. The recovery period lasted 30 min. Plasma growth hormone, prolactin, cortisol, catecholamine and lactate concentrations were measured at rest, during exercise and after recovery. The concentration of plasma growth hormone and catecholamine were not affected by partial sleep deprivation, whereas that of plasma prolactin was higher (P < 0.05) during the trial after an early awakening. Plasma cortisol was lower (P < 0.05) during recovery after both sleep deprivation conditions. Blood lactate was higher (P < 0.05) during submaximal exercise performed after both a delayed bedtime and an early awakening. Zolpidem-induced sleep did not affect the hormonal and metabolic responses to subsequent exercise. Our results demonstrate only minor alterations in the hormonal responses to exercise after partial sleep deprivation.  相似文献   

Improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids     

Nam-Trung Nguyen  Yee-Cheong Lam  Soon-Seng Ho    Cassandra Lee-Ngo Low 《Biomicrofluidics》2008,2(3)

This paper reports the improvement of rectification effects in diffuser∕nozzle structures with viscoelastic fluids. Since rectification in a diffuser∕nozzle structure with Newtonian fluids is caused by inertial effects, micropumps based on this concept require a relatively high Reynolds numbers and high pumping frequencies. In applications with relatively low Reynolds numbers, anisotropic behavior can be achieved with viscoelastic effects. In our investigations, a solution of dilute polyethylene oxide was used as the viscoelastic fluid. A microfluidic device was fabricated in silicon using deep reactive ion etching. The microfluidic device consists of access ports for pressure measurement, and a series of ten diffuser∕nozzle structures. Measurements were carried out for diffuser∕nozzle structures with opening angles ranging from 15° to 60°. Flow visualization, pressure drop and diodicity of de-ionized water and the viscoelastic fluid were compared and discussed. The improvement of diodicity promises a simple pumping concept at low Reynolds numbers for lab-on-a-chip applications.  相似文献   

Combinations of Epoch Durations and Cut-Points to Estimate Sedentary Time and Physical Activity Among Adolescents     

Andreas Fröberg  Christina Berg  Christel Larsson  Cecilia Boldemann  Anders Raustorp 《Measurement in physical education and exercise science》2017,21(3):154-160

The purpose of the current study was to investigate how combinations of different epoch durations and cut-points affect the estimations of sedentary time and physical activity in adolescents. Accelerometer data from 101 adolescents were derived and 30 combinations were used to estimate sedentary time, light, moderate, vigorous, and combined moderate-to-vigorous physical activity. Data were analyzed with repeated measurement analyses of variance. Large differences of sedentary time and times of different physical activity intensities were observed between 1 s and longer epoch durations using virtually all cut-points. Generally, sedentary time, moderate physical activity, vigorous physical activity, and combined moderate-to-vigorous physical activity progressively decreased, whereas light physical activity increased with longer epoch durations. The extreme differences between cut-points were large and increased with longer epoch durations for sedentary time and for all physical activity intensities except for vigorous physical activity per epoch duration. Caution is required when cross-comparing studies using different epoch durations and cut-points. To accurately register adolescents’ spontaneous intermittent physical activity behavior, short epoch durations are recommended.  相似文献   

Basic Serials Cataloging Workshop     

Les Hawkins  Hien Nguyen  Stephen Kharfen 《期刊图书馆员》2015,68(1-4):5-16

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Ly Tran,Simon Marginson,Hoang Do,Quyen Do,Truc Le,Nhai Nguyen,Thao Vu,Thach Pham and Huong Nguyen: Higher education in Vietnam: flexibility,mobility and practicality in the global knowledge economy     

Huong Thu Nguyen 《Higher Education》2015,70(5):899-901

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Student participation in elementary mathematics classrooms: the missing link between teacher practices and student achievement?     

Marsha Ing  Noreen M. Webb  Megan L. Franke  Angela C. Turrou  Jacqueline Wong  Nami Shin  Cecilia H. Fernandez 《Educational Studies in Mathematics》2015,90(3):341-356

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Social capital,human capital and parent–child relation quality: interacting for children’s educational achievement?     

Cecilia von Otter  Sten-Åke Stenberg 《British Journal of Sociology of Education》2015,36(7):996-1016

We analyse the utility of social capital for children’s achievement, and if this utility interacts with family human capital and the quality of the parent-child relationship. Our focus is on parental activities directly related to children’s school work. Our data stem from a Swedish cohort born in 1953 and consist of both survey and register data. We find that parents with more human capital tended to offer their children more social capital. OLS regressions showed that, when present, social capital was directly related to children’s grades and its utility for achievement did not depend on parents’ human capital. The utility of social capital was enhanced when combined with a very good parent-child relation.  相似文献   

Development and use of an instrument to measure students’ perceptions of a business statistics learning environment in higher education     

Thuyuyen H. Nguyen  Michael Newby  Panayiotis G. Skordi 《Learning Environments Research》2015,18(3):409-424

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Linear and orthogonal models of acculturation and its relations to cultural variables: An examination of the Suinn-Lew Asian Self-Identity Acculturation Scale (SL-ASIA)     

Tam K. Dao  Andra L. TetenQuang Nguyen 《Int J Intercult Relat》2011,35(1):61-68

The Suinn-Lew Asian Self-Identity Acculturation Scale (SL-ASIA) is the most widely used measure of acculturation for Asians. The purpose of the current study was twofold: First, the study explored the consistency of the SL-ASIA in characterizing Asian American men's level of acculturation - Asian-Identified, Western-Identified, Bicultural - using the items of the scale in orthogonal versus linear approaches. Second, the study examined the association between the two scoring methods and characteristics indicative of Asian culture—family allocentrism, loss of face, and affect intensity. An orthogonal approach suggests individuals may identify both with Asian and Western cultures, whereas a linear approach indicates an individual identifies with one culture at the expense of the other (e.g., high Asian, low Western identified). We examined the classification rates of these two methods using a large sample of Asian-American collegiate men (n = 521) and then within each ethnic subgroup of Asian men (e.g., Chinese, Japanese, Korean). Results suggested the two methods of characterizing men consistently diverged. Across the Asian subgroups, the overall agreement rates using linear and orthogonal methods were approximately at chance. Furthermore, significant correlations were observed among acculturation scoring methods and variables indicative of social integrity and family attitude. The implications for these findings and potential future directions for the study of acculturation are discussed.  相似文献