Sexual dimorphism in bone–muscle relationship in young adults

The purpose of this study was to analyse associations between lean soft tissue (LST), a surrogate of skeletal muscle mass and key fracture-related geometric characteristics of the proximal femur. Moreover, we examined the role that muscle played on the proximal femur geometry in response to physical activity (PA). Participants were 83 young adults. Leg LST (exposure) was assessed by dual energy X-ray absorptiometry (DXA). Proximal femur geometry was derived from a left hip DXA scan. Geometric variables (outcomes) included the femoral neck axis length (FNAL), the femoral neck width (FNW), the neck–shaft angle and FNW|FNAL (an index of robustness). PA was evaluated by accelerometry. Linear regression was used to analyse relationships. Additional exposure variables included body height and mass. In males, leg LST explained 17.4% of variation in FNAL (P < 0.001) and 15% in FNW (P = 0.015). In females, it explained 8.8% of the variance in FNAL (P = 0.020). Associations remained significant in males, but not in females, when vigorous PA was added to the models. These results suggest that public health approaches to promote PA may be particularly important in females since vigorous PA seems to convey advantages in femur geometry and consequently in bone strength.     

Exercise but not metformin improves health-related quality of life and mood states in older adults with type 2 diabetes

The aim of this cohort study is to analyse the effect of three types of treatment: (i) exercise training with multicomponent exercise (E); (ii) pharmacologic treatment with oral hypoglycaemic drug – metformin (M); and (iii) a combined therapy – exercise and metformin (E?+?M) on health-related quality of life (HRQoL) and mood states in older adults with type 2 diabetes (T2D) with comorbidity in an early stage of the disease. Participants (n?=?284) underwent 1 of the following 3 conditions: (i) E (n?=?59) trained three times/week; (ii) M (n?=?30) used 850?mg of metformin twice daily; and (iii) E?+?M (n?=?195) combined exercise and metformin. Furthermore, participants completed baseline and 2-year follow-up evaluations including a Shortform Health Survey 36, Profile of Mood States – Short-form, the health history questionnaires, anthropometric, and blood biochemistry. E and E?+?M revealed improved mood states, with large effect size on the vigour domain, and moderate effect size in the anger and total mood disturbance (TMD) domains (P?<?0.05), in comparison with the M group. After 24 months’ intervention, the E and E?+?M groups perceived better physical and mental HRQoL than the M group. The M group unchanged HRQoL domains (P?>?0.05). Metformin had no significant effect on the self-referred HRQoL in T2D participants aged above 60 years, in an early stage of the disease. The E and E?+?M were the most effective long-term therapies to improve mood states and HRQoL in older adults with T2D.     

面向中华古籍阅读推广与文化传播的VR系统模型构建与实现

[目的/意义] 旨在借助VR媒介技术,克服或弱化普通读者在古籍阅读中存在的古籍获取不便和古汉语理解、专业知识、特定文化背景知识、阅读动力不足的问题,促进古籍阅读推广与文化传播。[方法/过程] 利用文献调研方法分析梳理认知科学和教育技术领域相关理论,提出VR古籍系统设计原则与模型,基于单个案例分析,设计、开发、测试系统原型,最后利用实验方法以问卷方式收集评估数据,验证设计原则、模型的有用性。[结果/结论] 研究成果包括VR古籍系统设计原则、VR古籍系统理论模型、首例VR古籍系统应用原型、VR古籍系统使用理论,可为后续从事VR古籍系统研究与设计的科研人员和设计人员借鉴使用。     

Physical fitness percentiles for Portuguese children and adolescents aged 10–18 years

Abstract

This study aimed to produce age- and sex-specific physical fitness reference data for Portuguese youth; to report the prevalence of youth in the healthy zone of physical fitness according to the FITNESSGRAM^® criteria; to verify the agreement between the Portuguese physical fitness percentiles and the FITNESSGRAM^® healthy zones. In 2008, 22,048 Portuguese children and adolescents (10–18 years) were evaluated. Physical fitness (curl-ups, push-ups, 20-m shuttle run and modified-back-saver-sit-and-reach tests) was evaluated using the FITNESSGRAM^® Test Battery 8.0. Smoothed percentile curves were estimated using Cole’s LMS method. Boys consistently outperformed girls in every physical fitness test, except for the modified-back-saver-sit-and-reach tests. In both sexes and for all physical fitness tests, higher percentile values were observed at older ages. The 50th percentile of all physical fitness tests had the highest accuracy to discriminate between under healthy zone and healthy zone of the FITNESSGRAM^®. Portuguese schools and physical education teachers may considerer the 50th percentile for age and sex or the FITNESSGRAM^® criteria for classifying participants in the healthy zone as acceptable cut-offs, above which youth should be considered fit. These reference values can be used as normative data and for baseline values for subsequent surveillance of the physical fitness of Portuguese youth.     

Establishment of higher education institutions and new firm entry

The presence of universities has generally been associated with technological entrepreneurship. But what is the real impact of new universities on the levels of firm creation in a region? The present paper uses policy evaluation methodologies and longitudinal data on the establishment of higher education institutions in Portuguese municipalities for the period 1992-2002 to examine its effect on entry rates of new firms in different sectors. We find that the establishment of a new university has a positive and significant effect on subsequent levels of knowledge based firm entry in municipalities, and a negative effect on the levels of entry in other sectors, such as low-tech manufacturing.     

Constructing Scientific Explanations: a System of Analysis for Students’ Explanations

Research in Science Education - This article describes a system of analysis aimed at characterizing students’ scientific explanations. Science education literature and reform documents have...     

Perspectives on the Origins of Life in Science Textbooks from a Christian Publisher: Implications for Teaching Science

This study analyzes six seventh grade Israeli mathematics textbooks, examining (1) the extent to which students are required to justify and explain their mathematical work, and (2) whether students are asked to justify a mathematical claim that is stated by the textbook or a mathematical claim that they themselves generated when solving a problem. Two different units of analysis were used to analyze two central topics in the seventh grade curriculum as follows: (1) equation solving in algebra and (2) triangle properties in geometry. The findings indicate that all six textbooks had considerably larger percentages of geometric tasks than algebraic tasks, which required students to justify or explain their mathematical work. Moreover, considerable differences were found among the six textbooks regarding the percentages of tasks that required students to justify and explain in both topics, but more so with the algebraic topic. Analysis of whether the textbook tasks required students to justify a mathematical claim that is stated by the textbook or a mathematical claim that the students themselves generated also revealed substantial differences among the textbooks. These findings are discussed, as well as the research methods used, in light of relevant literature.     

Patterns of accelerometer-derived sedentary time across the lifespan

ABSTRACT

We aimed to describe ST and its patterns on a national level. A hip-worn accelerometer (ActiGraph GT1M) was used to collect data during waking hours from 4575 Portuguese’ participants from 2007–2009 (2683 females) aged 10–102 years old. Data was presented by sex, in 5-years age intervals, and by adolescents (n=2833), adults (n=1122), and older adults (n=620). Lambda-mu-sigma (LMS) smoothed percentile curves were estimated. Girls, women, and older women spent 61, 57, and 64% of wear time in ST, respectively. In males, ST represented 57, 60, and 62% of wear time respectively for boys, men, and older men. Comparing to other age groups, older adults spent a larger amount of ST in bouts ≥30-min (women: 33%, men: 39% of total ST). The number of breaks/ST hour were: 10.6 in girls, 11.7 in women, and 9.6 in older women. In males, the number of breaks/ST hour were: 11.2, 10.5, and 8.5 for boys, men, and older men. In conclusion, ST was not consistently higher at older ages. Instead, we found that the potential critical moments in which ST may be higher are during adolescence and in the transition from adulthood into older adulthood, which represents critical periods for interventions.