Electrocortical and behavioral responses of low, moderate, and high physically active older adults were compared with a younger control group on neutral and incompatible conditions of a flankers task. Compared to younger adults, high and moderate active older adults exhibited increased event-related potentials component P3 amplitude for the incompatible condition at the frontal electrode site. For the neutral condition, only low active older adults exhibited decreased amplitude at the central-parietal site, compared to younger adults. P3 latency revealed the longest latencies for low active older adults, followed by moderate active, high active, and younger adults, respectively. Reaction time (RT) data revealed that younger adults exhibited faster RT compared to all three older groups. Results suggest that physical activity may improve executive control function in older adults by affecting the distribution of P3 amplitude, which has been related to memory and attentional processes, and by decreasing P3 latency, which relates to the speed of cognitive processing. 相似文献
Thigh muscle volume is a useful determinant of functional fitness. However, anthropometric prediction of muscle content is influenced by the variability of adipose tissue accumulation. The aims of this study were to predict thigh muscle and adipose tissue volumes from anthropometry and to assess the validity of the method by examining the various components of the measurements and the assumptions involved. The 19 participants (9 men, 10 women; age 23-49 years) varied in adiposity. They all underwent magnetic resonance imaging (MRI) of the upper leg and the eight men and two women with the lowest adiposity underwent detailed anthropometry involving girths and skinfolds. Using MRI as the reference method, muscle volume was predictedfrom anthropometry using a circular concentric model, and the assumptions inherent in the method were tested further using the MRI data alone. Muscle volume was best predicted by anthropometry in the 10 leanest participants using a five-slice truncated cone model that overestimated the mean MRI value by 30% (R2 = 0.95; standard error of estimate = 288 cm3; P < 0.001). A single skinfold plus girth measurement at the mid-thigh almost matched its predictive ability, but with an increased bias. Measurements of leg circumference by means of the two techniques agreed well. The assumption of a circular cross-section was valid. In contrast, the agreement between skinfold thickness measured by caliper and superficial adipose tissue thickness by MRI was poor, contributing to the scatter of fat and lean area comparisons. An anterior skinfold thickness measurement underestimated the area of superficial adipose tissue at that level, particularly at the most proximal and distal sites. Although these limitations increase the uncertainties of muscle volume determination by anthropometry, they do not prevent its valid prediction in leaner individuals. The prediction of superficial adipose tissue was poorer. 相似文献
This study summarizes a survey conducted to discover the extent to which professional librarians in Nigerian university libraries have achieved academic/faculty status. The survey revealed that: (1) almost all professional librarians (16 or 80%) in Nigerian universities have full faculty status, coupled with mandatory research and publication for promotion, in 17 (85%) of the libraries; (2) publications in subject-fields and in library/information science carry equal ratings; and (3) academic librarians in Nigeria are entitled to the same rights, privileges and responsibilities as their teaching counterparts. This paper urges the Nigerian Library Association and the Committee of University Librarians to set standards for the attainment of faculty/academic status for professional librarians in Nigerian universities and colleges. 相似文献
The objective of the present study was to investigate the effects of combined training without caloric restriction on inflammatory markers in overweight girls. Thirty-three girls (13–17 years) were assigned into overweight training (n = 17) or overweight control (n = 16) groups. Additionally, a normal-weight group (n = 15) was used as control for the baseline values. The combined training programme consisted of six resistance exercises (three sets of 6–10 repetitions at 60–70% 1 RM) followed by 30 min of aerobic exercise (walking/running) at 50–80% VO2peak, performed in the same 60 min session, 3 days/weeks, for 12 weeks. Body composition, dietary intake, aerobic fitness (VO2peak), muscular strength (1 RM), glycaemia, insulinemia, lipid profile and inflammatory markers (C-reactive protein, interleukin-6, tumour necrosis factor-alpha, interleukin-10, leptin, resistin and adiponectin) were measured before and after intervention. There was a significant decrease in body fat (P < 0.01) and increase in fat-free mass (P < 0.01), VO2peak (P < 0.01), 1 RM for leg press (P < 0.01) and bench press (P < 0.01) in the overweight training group. Concomitantly, this group presented significant decreases in serum concentrations of C-reactive protein (P < 0.05) and leptin (P < 0.05), as well as in insulin resistance (P < 0.05) after the experimental period. In conclusion, 12 weeks of combined training without caloric restriction reduced inflammatory markers associated with obesity in overweight girls. 相似文献
We offer a theoretical and ecological argument for the preparation of citizens in U.S. public schools. This democratic education
draws legitimacy from the concern of the nations founders for a populace educated to govern itself. We also emphasize the
need for new democratic skills and knowledge in the face of today’s challenges, and our responsibility to prepare the young
for the 21st century. A critique of the current school reform movement is provided because of its undemocratic nature. We
issue a call for the transformation to democratic schools. We specifically argue that current efforts at reform are maintaining
historical inequities, while also depriving those that enjoy social and economic advantages of the education needed to meet
the challenges of a rapidly changing world. The democratic education proposed is based on three goals: citizenship preparation, inclusion, and an optimum learning environment. Seven well established principles of democracy and their relationship to schooling are presented. These include; the nature
of authority, inclusiveness, equal availability of the understanding required for deliberating the most serious challenges
to democracy and livability, equal access to centers of political decision-making, guaranteed inalienable rights, equality,
and universal access to an optimum learning environment. We offer a fundamentally different approach to educational reform:
calling for a reassessment of the role of public schools in a democracy that recognizes the importance of citizenship preparation,
and a “bottom up” reform model that starts in the classroom and can be implemented by individual teachers. 相似文献
The purpose of this study was to determine the differences between third and sixth grade female and male students when retelling orally a story read silently. The students' retelling of the story was analyzed by comparing how closely, both structurally and linguistically, they paralleled the T-units or communication units of the author. In general, female students performed significantly differently than did male students. The researchers examine these differences in light of recent research in the area of gender differences. 相似文献
Although research suggests that the use of child-initiated vs. teacher-directed instructional practices in early childhood education has implications for learning and development, the precise nature of these effects remains unclear. Using data from the Midwest Child-Parent Center (CPC) Expansion Project, the present study examined the possibility that a blend of child- and teacher-directed practices best promotes school readiness among preschoolers experiencing high levels of sociodemographic risk and explored whether the optimal blend varies based on child characteristics. Sixty-two CPC preschool teachers reported their instructional practices throughout the year, using a newly developed questionnaire—the Classroom Activity Report (CAR). The average reported proportion of child-initiated instruction was examined in relation to students’ end-of-year performance on a routine school readiness assessment (N = 1289). Although there was no main effect of child-initiated instruction on school readiness, there was a significant interaction between instruction and student age. Four-year-olds’ school readiness generally improved as the proportion of child-initiated time increased, while 3-year-olds showed a U-shaped pattern. The present findings add to the evidence that child-initiated instruction might support preschoolers’ school readiness, although they also suggest this relation may not always be linear. They also point to the importance of examining instructional strategies in relation to student characteristics, in order to tailor strategies to the student population. The CAR has potential as a brief, practical measurement tool that can support program monitoring and professional development.