Associations of accelerometer-measured sedentary time,sedentary bouts,and physical activity with adiposity and fitness in children

ABSTRACT

Sedentary time (ST) has been inconsistently associated with adiposity and cardiorespiratory fitness in children in previous studies. We studied cross-sectional associations of ST, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with fat mass index (FMI) and cardiorespiratory fitness (estimated VO₂max). Associations were evaluated with and without considering pattern of ST by bout length. We measured ST and activity by a wrist-worn accelerometer, FMI by bioelectrical impedance, and VO₂max by Pacer test in 443 children (51.2% girls, 10.2 ± 0.6 years). Isotemporal substitution regression models estimated the effects of substituting ST, LPA, and MVPA on FMI and VO₂max. Further models repeated analyses separating ST into short (<10 min) and long (≥10 min) bouts. Only replacing ST or LPA with MVPA was consistently associated with lower FMI and greater VO₂max. When separated by bout length, only one unique association was found where replacing long ST bouts with short ST bouts was associated with lower FMI in girls only. In conclusion, activity pattern is associated with adiposity in girls and fitness in boys and girls. Separating ST into long and short ST bouts may be of minimal importance when assessing associations with adiposity and fitness using wrist-worn accelerometry in children.     

Conceptions of Biology and Approaches to Learning of First Year Biology Students: Introducing a technique for tracking changes in learner profiles over time

We surveyed first year students at the start and at the end of their first semester of university biology (n?=?285) as to their approaches to study (surface, deep) and their conceptions of biology (fragmented, cohesive). Hierarchical cluster analysis was used to group students who responded similarly to the survey; this resolved four Learner Profiles based on specific combinations of approach to study and conception of biology. By comparing cluster membership at the start and end of the semester we could assess whether students (1) maintained their incoming approach to study and conception of the discipline of biology, i.e. their ‘Learner Profile’ and (2) whether certain Learner Profiles were more persistent than others. Approximately half the student cohort did not alter their approach to study or conceptions of biology by semester's end. Students in the disengaged profile, i.e. who returned mostly negative responses to survey items, appeared the most resistant to changing their Learner Profile; while the greatest migration occurred towards less than desirable learning strategies (particularly to the disengaged profile). We were able to confirm the significant migration patterns by assessing the heterogeneity of each cluster at the start of semester clusters with respect to the students' approaches and conceptions at the end of semester. Thus we present a process to accurately track Learner Profile changes that may tell us more about how we can enhance students' learning and provide a means by which to gather the empirical data to support decisions relating to curriculum change.     

欧洲语言教师教育纲要述评与启示

《欧洲语言教师教育纲要》是关于21世纪欧盟国家外语教师(初任和在职)教育的一个纲领性文件。该文件主要涉及外语教师教育的构成和组织,外语教学的核心——对于教学的认知,外语教学策略和技能,以及语言教学过程中鼓励和倡导多种价值观四个方面。其出台不仅为欧洲语言教师教育提供了具体发展方向和依据,也能为我国外语教师教育政策制定提供重要借鉴。     

Personal ontologies: Generation of user profiles based on the YAGO ontology

Personalized search is aimed at tailoring the search outcome to users; to this aim user profiles play an important role: the more faithfully a user profile represents the user interests and preferences, the higher is the probability to improve the search process.     

Effects of flaxseed<Emphasis Type="Italic">(Linum usitatissimum) chutney</Emphasis> on gamma-glutamyl transpeptidase and micronuclei profile in azoxymethane treated rats

Antioxidant property of flaxseed chutney was evident by decreasing lipid peroxidation (TBARS) and predictor enzyme γ-glutamyl transpeptidase profile and micronuclei formation in azoxymethane treated rats. After 10 weeks, rats fed with either fiber-free basal diet or Antioxidant diet exhibited over sevenfold increase in γ-glutamyl transpeptidase activity and nearly fourfold increase in micronuclei load in comparison to controls (p<0.001). A significant reduction in both γ-glutamyl transpeptidase level (52%) and micronuclei formation (47%) was observed in fiber-free basal diet/Antioxidant diet/flaxseed chutney diet fed rats. Relative to rats fed fiber-free basal diet, the profile of γ-glutamyl transpeptidase and micronuclei load was not significantly altered.     

The Russian avant-garde painting palette: Documentary and physicochemical codification of organic colorants

In the present article an attempt is made to elucidate the organic colorants commonly encountered in the Russian avant-garde painting palette by a combined art historical, documentary and physicochemical investigation, and to examine the influence of environmental factors on the chromatic profile originally sought by the artist. The overall approach based on written sources is confirmed by measurements on relevant paintings. The documentary research deals with the influences of Orthodox iconography, folkloric art, and occidental modernist tendencies on the Russian avant-garde palette, and studies the effects of contradictory historical processes in the chromatic profile of individual paintings. In the experimental section a series of colorants are investigated concerning the effects of accelerated ageing on experimental painting tables, prepared as watercolor and gouache layers on paper ground. The resulting samples are subjected to colorimetric and spectroscopic measurements, and analogous analytical procedures are applied on samples taken from selected paintings. A systematic comparative study of all data permits evaluation of the materials used in terms of their stability towards extrinsic factors, and proposal of degradation routes in order to assist museum curators and conservators in every concrete case related to the broad spectrum of pigments examined.     

Neuromuscular,metabolic and hormonal profiles of young tennis players and untrained boys

This study compared the neuromuscular, metabolic and hormonal profiles of trained prepubescent tennis players and an untrained group. The boys in the experimental group (n = 9; mean age ± S.D. = 11.4 ± 0.5 years) had participated in tennis training for 2.3 ± 1.0 years and the boys in the control group (n = 9; mean age ± S.D. = 10.9 ± 0.4 years) were normal active volunteers. The tennis players were found to be physically more active than the controls when the comparison was made for either 1 year (4.9 ± 1.8 vs 2.6 ± 2.5 times per week; P<0.05) or for 1 week (3.4 + 1.2 vs 0.4 ± 0.5 times; P < 0.001) preceding the tests. Choice reaction time was significantly (P <0.01) shorter in the experimental group (258 ± 16 ms) than in the control group (344 + 81 ms). Dropping height in the best drop jump was significantly (P< 0.05) higher in the tennis players (0.46 + 0.19 m) than in the control boys (0.27 ± 0.10 m). The tennis players had significantly lower oxygen consumption at the ‘anaerobic threshold’ than the controls (P < 0.05). There were no significant differences between the groups in serum hormone levels. The small differences that existed may have been caused by actice participation in sport by the tennis players.