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71.
This is the fourth in a series of articles exploring international trends in health science librarianship in four Southern European countries in the first decade of the 21st century. The invited authors are from Greece, Italy, Spain and Portugal. Future issues will track trends in Latin America and Central Europe. JM  相似文献   
72.
Abstract

In this study, we investigated the effect of biological maturation on maximal oxygen uptake ([Vdot]O2max) and ventilatory thresholds (VT1 and VT2) in 110 young soccer players separated into pubescent and post-pubescent groups.. Maximal oxygen uptake and [Vdot]O2 corresponding to VT1 and VT2 were expressed as absolute values, ratio standards, theoretical exponents, and experimentally observed exponents. Absolute [Vdot]O2 (ml · min?1) was different between groups for VT1, VT2, and [Vdot]O2max. Ratio standards (ml · kg?1 · min?1) were not significantly different between groups for VT1, VT2, and [Vdot]O2max. Theoretical exponents (ml · kg?0.67 · min?1 and ml · kg?0.75 · min?1) were not properly adjusted for the body mass effects on VT1, VT2, and [Vdot]O2max. When the data were correctly adjusted using experimentally observed exponents, VT1 (ml · kg?0.94 · min?1) and VT2 (ml · kg?0.95 · min?1) were not different between groups. The experimentally observed exponent for [Vdot]O2max (ml · kg?0.90 · min?1) was different between groups (P = 0.048); however, this difference could not be attributed to biological maturation. In conclusion, biological maturation had no effect on VT1, VT2 or [Vdot]O2max when the effect of body mass was adjusted by experimentally observed exponents. Thus, when evaluating the physiological performance of young soccer players, allometric scaling needs to be taken into account instead of using theoretical approaches.  相似文献   
73.
Abstract

The aims of the this prospective study were to analyse physical activity (PA) engagement during the first and second trimesters, considering the different guidelines published on PA, to document the individual characteristics associated with the accomplishment of these guidelines and to examine pregnant women’s perceived barriers to leisure PA, using a socioecological framework. A sample of 133 pregnant women in two stages – at 10–12 weeks’ gestation (T1) and 20–22 weeks’ gestation (T2) – were evaluated. PA was assessed by accelerometry during the T1 and T2 evaluation stages. Socio-demographic characteristics, lifestyle factors and barriers to leisure PA were assessed via questionnaire. A large proportion of women (ranging from 32% to 96%) did not reach the levels of PA recommended by the guidelines. There were no significant differences between T1 and T2 with regard to compliance with PA recommendations. A decrease in PA levels from T1 to T2 was noted for all recommendations. No associations were found between participants’ characteristics and adherence to the recommendations in T1 and T2. No significant differences were found in barriers to leisure PA between T1 and T2. The most commonly reported barriers to leisure PA were intrapersonal, not health related. Our results indicate that there were no differences between trimesters regarding compliance of PA recommendations, and perceived barriers were similar in both trimesters.  相似文献   
74.
The aim of this study was to determine the influence of breathing frequency and tidal volume on resting heart rate variability in children aged 9 years ( n = 29) and 16 years ( n = 19). Heart rate variability was measured in four conditions: (1) without the control of ventilation followed at random by (2) a fixed breathing frequency of 12 breaths· min -1 , (3) a breathing frequency of 12 breaths· min -1 but with a fixed tidal volume of 30% vital capacity and (4) a fixed breathing frequency of 6 breaths·min -1 and a tidal volume of 30% vital capacity. A total of 128 RR intervals (the time between two spikes in the heart rate) were detected and absolute high- and low-frequency spectral components were calculated using autoregressive modelling. The younger children were unable to control ventilation to achieve conditions 3 and 4; therefore, a 2 2 2 (group 2 condition) analysis of variance was used to analyse conditions 1 and 2. There were significant interactions between group and heart rate variability conditions for the low-frequency component and the ratio of low to high frequencies ( P ? 0.001). The main effect for condition showed that at 12 breaths· min -1 with no fixed tidal volume there was a significantly higher standard deviation of the RR interval, total power and high-frequency ( P ? 0.01) and lowfrequency spectral components ( P ? 0.05) than in the condition with no ventilatory control. Across the four breathing conditions for the older participants, the high-frequency spectral component was significantly higher in the condition at 6 breaths· min -1 with a fixed tidal volume than in that with no ventilatory control ( P ? 0.005); the ratio of high to low frequencies was significantly lower for the spontaneous condition than those performed at 12 breaths· min -1 ( P ? 0.001). The results provide evidence of the need for ventilatory control when assessing short-term resting heart rate variability in children.  相似文献   
75.
There has been much research on principles and fundamental concepts of mechanics. Problems concerning the law of inertia, the concepts of force, fictitious force, weight, mass and the distinction between inertial and gravitational mass are addressed in the first part of the present paper. It is argued in the second that the law of inertia is the source of these problems. Consequences drawn from the law explain the metaphysical concept of force, the problematic concept of fictitious force, the nominal definition of weight and the difficulty with defining mass operationally. The core of this connection between the law and these consequences lies in the fact that acceleration is a sufficient condition for force. The experimental basis of the law in the course of its history shows, however, that the law presupposes acceleration necessarily whereas acceleration does not presuppose the law. Therefore, there is no inconvenience in taking acceleration independently of the law. This is enough to bypass those problems. Taking into account how force is measured by force meters and how mass is basically determined, by comparison with the standard mass, a minimal meaning for both concepts of force and mass is established. All this converges with several solutions proposed in the course of history and increases the communicability of mechanics, as outlined in the final part of this paper.  相似文献   
76.
角色理论视角下的民族认同与国家认同教育   总被引:1,自引:0,他引:1  
民族认同与国家认同教育一直是我国民族地区学校教育的重要内容,特纳的过程角色理论尽管是从社会学的角度来探讨个体角色的形成机制,但对我国民族地区学校的民族认同与国家认同教育不无启发意义.本文以特纳的角色理论为视角,探讨民族地区学校教育如何帮助少数民族学生通过角色认同与角色互动实现民族认同与国家认同的统一.  相似文献   
77.
Context-based curriculum reforms in chemistry education are thought to bring greater diversity to the ways in which chemistry teachers organize their teaching. First and foremost, students are expected to perceive this diversity. However, empirical research on how students perceive their teacher's teaching in context-based chemistry classrooms, and whether this teaching differs from traditional chemistry lessons, is scarce. This study aims to develop our understanding of what teaching looks like, according to students, in context-based chemistry classrooms compared with traditional chemistry classrooms. As such, it might also provide a better understanding of whether teachers implement and attain the intentions of curriculum developers. To study teacher behaviour we used three theoretical perspectives deemed to be important for student learning: a content perspective, a learning activities perspective, and an interpersonal perspective. Data were collected from 480 students in 24 secondary chemistry classes in the Netherlands. Our findings suggest that, according to the students, the changes in teaching in context-based chemistry classrooms imply a lessening of the emphasis on fundamental chemistry and the use of a teacher-centred approach, compared with traditional chemistry classrooms. However, teachers in context-based chemistry classrooms seem not to display more ‘context-based’ teaching behaviour, such as emphasizing the relation between chemistry, technology, and society and using a student-centred approach. Furthermore, students in context-based chemistry classrooms perceive their teachers as having less interpersonal control and showing less affiliation than teachers in traditional chemistry classrooms. Our findings should be interpreted in the context of former and daily experiences of both teachers and students. As only chemistry is reformed in the schools in which context-based chemistry is implemented, it is challenging for both students and teachers to deal with these reforms.  相似文献   
78.
Modelling is an inherent process for the construction and use of science concepts that mobilize diverse specific competences. The aims of this work are to put forward a means of evaluating modelling competences that is relevant for physics teaching and science education research and to identify the potentials and constraints in the development of modelling competences. A written test, which embraces a wide range of modelling aspects in mechanics domain, was drawn up and validated, and a theoretically based evaluation methodology was specified. In the validation process, the test was given to 75 subjects distributed across seven levels of physics education. The answers were analysed and later cluster analysis was carried out in order to identify categories of answers among the diverse answers. The results indicate that the test identified and delimitated modelling competences. Some results are in agreement with those obtained through other research into this issue and other results better elucidate certain aspects of modelling. The way in which evaluation methodology can be used in other areas of physics is discussed, such as in research and in teaching. Also discussed is how the constraints and potentials identified in the development of modelling competences can be taken into account in teaching and learning sciences.  相似文献   
79.
ABSTRACT

An experiential education program was designed to target risk perceptions and preventative measures that make people feel comfortable in human-coyote interactions. The research was conducted in a Canadian national park where a coyote caused a human fatality in 2009. Based on previous research, we explored the effects of an experience-based coyote education program on people's (a) attitudes toward, (b) fear of, (c) likelihood of, and (d) control over coming into contact with coyotes. A pre-post-test experiment (n = 150; 96% completion rate) was conducted. The experiential education approach to wildlife safety and coexistence communication had a significant positive effect on people's attitudes, significantly decreased their sense of fear toward coyotes, significantly decreased their sense of likelihood, and increased their sense of control in human-coyote interactions.  相似文献   
80.
In this paper, academic developers from universities in three countries explore underlying assumptions about what we as developers do and why we do it in relation to evaluating development programs. Through addressing three questions, key ideas emerge that highlight what is often overlooked in day-to-day practice: the fact that academic development has a ‘signature pedagogy’ defined by the ‘learning paradigm’; the potential role of different stakeholders in setting criteria for evaluation; and the inclusion of non-traditional academic development literatures (e.g., adult education, educational change, organizational development) to avoid perpetuating established practices. Our intent is to intellectually challenge ourselves and others to move beyond sharing program and evaluation activities to explore ideas and literature not often considered in our day-to-day work. While the context is academic development, we believe the questions and the answers that emerged are of value to all involved in staff and professional development.  相似文献   
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