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81.
The aim of this study was to determine if the hypoxaemic stimulus generated by intense exercise results in the physiological response of increased erythropoietin production. Twenty athletes exercised for 3 min at 109 +/- 2.8% (mean +/- s) maximal oxygen consumption. Estimated oxyhaemoglobin saturation was measured by reflective probe pulse oximetry (Nellcor N200) and was validated against arterial oxyhaemoglobin saturation by CO-oximetry in eight athletes. Serum erythropoietin concentrations-as measured using the INCSTAR Epo-Trac radioimmunoassay-increased significantly by 28 +/- 9% at 24 h post-exercise in 11 participants, who also had an arterial oxyhaemoglobin saturation < or = 91% (P < 0.05). Decreased ferritin levels and increased reticulocyte counts were observed at 96 h post-exercise. However, no significant changes in erythropoietin levels were observed in nine non-desaturating athletes and eight non-exercise controls. Good agreement was shown between arterial oxyhaemoglobin saturation and percent estimated oxyhaemoglobin saturation (limits of agreement = -3.9 to 3.7%). In conclusion, short supramaximal exercise can induce both hypoxaemia and increased erythropoietin levels in well-trained individuals. The decline of arterial hypoxaemia levels below 91% during exercise appears to be necessary for the exercise-induced elevation of serum erythropoietin levels. Furthermore, reflective probe pulse oximetry was found to be a valid predictor of percent arterial oxyhaemoglobin saturation during supramaximal exercise when percent estimated oxyhaemoglobin saturation > or = 86%.  相似文献   
82.
83.
The purpose of these studies was to examine the relationship between perceptions of exercise-related changes (i.e., perceived mastery and physical change) and certainty with regard to the self-as-exerciser. It was hypothesized that seeing "change" would be associated with more favorable levels of exercise self-certainty and behavior relative to "no change." Online surveys were repeatedly administered across 4 months (Study 1) and 4 weeks (Study 2) to 196 university students (M(age) = 20.17), and 250 community dwellers (M(age) = 38.44), respectively. Data were analyzed via latent variable modeling procedures. Consistent with hypotheses, latent classes (i.e., subgroups) reflecting interindividual differences in levels and trajectories of perceived change were associated with distinct patterns of self-certainty and exercise behavior. The findings suggest that adults who experience mastery of skills and physiological changes also have greater self-certainty and exercise more regularly than those who do not see progress or feel as certain of their exercise identity.  相似文献   
84.
Gymnastics vaulting relies on a specialized take‐off board for propulsion during the take‐off phase of the vault. There is little information on the vault board and its behaviour. The aim of this study was to characterize the behaviour of the vault board during handspring drill take‐offs of young male gymnasts (n = 36). The side of the top surface of the vault board and the wooden base were marked with three reflective markers, placed at the end of the vault board nearest the vault table and the centres of the two rearmost coil springs. The vault board surface was divided into two areas, rear and middle, based on marker location. The gymnasts’ groups were determined from the location of the gymnast's lateral malleolus at vault board contact. Landings with the malleolus directly above or behind the rearmost marker were considered rear landings; landings with the malleolus forward of the rearmost marker were considered middle landings. Marker movements were automatically digitized and the right malleolus was hand digitized at 120 Hz. The maximum vertical displacement, vertical deflection time, and vertical velocity at take‐off of the vault board markers did not differ statistically between board contact groups (all p > 0.05). The lateral malleolus velocity components also did not differ between board contact groups. Some low to moderately strong correlations were observed between the various marker displacements, durations and take‐off velocities. Modest correlations were obtained between board markers and right malleolus velocities. The results indicate that foot contact on the vault board, as defined here, did not result in differences in board marker behaviour or right lateral malleolus velocities. This information does not support the idea that vault board contacts at the rear of the vault board are worse than contacts near the middle of the vault board. More research is needed to ascertain the role of the vault board's vibration characteristics to whole body actions that are observed in the subsequent preflight phase.  相似文献   
85.
Improving children's attendance is a high priority for Head Start and other early childhood education programs serving low-income children. We conducted a randomized control trial in a major northern city to evaluate the impact of a low-cost intervention designed to promote parents' social capital as a potential influence on children's attendance in Head Start centers. The intervention assigned children to treatment group classrooms based on (a) neighborhood of residence (geography condition) or (b) the geography condition plus the opportunity for parents to form partnerships in support of their children's attendance, or to control group classrooms according to Head Start guidelines only. We did not find impacts on average attendance throughout the year. However, the intervention did lead to increased attendance during the winter when average center attendance was lowest. There were no impacts on fall or spring attendance. Follow-up exploratory analyses of focus groups with parents and staff suggested that parents' level of connection and trust, self-generated partnership strategies, and commitment to their children's education may be factors by which parents' social capital expands and children's attendance improves.  相似文献   
86.
Twenty‐three preschool‐age children, 3;6 (years; months) to 4;1, were videotaped separately with their mothers and fathers while each mother and father read a different unfamiliar storybook to them. The text from the unfamiliar storybooks was parsed and coded into story grammar elements and all parental extratextual utterances were transcribed and coded for (1) their relationship to the story grammar elements found within the storybook, and (2) the natural strategies parents used to direct their children's attention to these elements. Children's overall exposure to story grammar elements during book reading was also explored for its relationship to their language abilities. Results indicated that parents focused significantly more on the resolution, attempt, and consequence compared to the initiating event and plan, and most frequently used the text and pictures as strategies for recruiting their children's attention to the story grammar elements within the book. In addition, the frequency of parental utterances related to story grammar elements was negatively correlated with children's language abilities. This study did not examine the complexity or depth of parental utterances related to story grammar elements. These findings provide initial evidence that children may derive their understanding of story grammar at least in part through their parents' extratextual discussions during parent–child book reading.  相似文献   
87.
This paper describes teachers, parents and educational psychologists working together to meet the needs of children and young people with autistic spectrum difficulties in mainstream and special schools. It examines the impact on children's social behaviour of a two-session workshop for groups of parents/carers, teachers and learning support assistants about 'Social Stories' (Gray, 1994). It highlights the contribution that Social Stories can make to the management of a wide range of social behaviours, including inappropriate sexual behaviour, unsafe behaviour and obsessional behaviour. Issues raised by the use of Social Stories and their benefits for children with autistic spectrum difficulties are considered. The paper concludes by describing the developing diversity in the use of Social Stories and invites those working in the field to contribute to the body of information about their strengths and limitations.  相似文献   
88.
Patterns of development in language and play for full term and preterm children from 6 to 54 months and the effects of maternal parenting strategies (i.e., maintaining attentional focus, use of directiveness) were examined. Significant risk differences in the growth of both language and play were found. The high risk children were more likely to show delays in both these skills. Maintaining had a positive influence on children's skills, while directiveness had a largely negative influence, especially at older ages. The relation between growth in play and language was stronger for the high risk, preterm, when compared to the low risk and full term, children, but only during the infancy and toddler period. Given that play and language development is more likely to be delayed for preterm, high-risk children and the relation between the development of these skills is stronger for high risk preterm children, particularly early, it would be important to provide the parents and educators with information about play and language development. For example, communicating the need to be consistent in using some interactive behaviors (e.g., maintaining) as children develop while modifying other behaviors (e.g., directiveness) would be essential.  相似文献   
89.
Students have expectations of their university education leading to graduate careers, with universities investing considerable resources in institution-wide initiatives designed to enhance opportunities for student work placements and work-related learning. However, there are large variations between courses and disciplines in student uptake of these opportunities, with limited evidence explaining why this might be the case. Recognising recent approaches which consider student identity in transitions, this study explored student attitudes to work-related learning across a range of subject disciplines. The first phase of the study used in-class surveys (N = 199) to focus on students’ self-identification and perceptions of employability initiatives. Follow-up interviews were conducted to further explore themes emerging in the survey data. The study found that, while some students drew on resources for identity work in their recognition of and approach to work-related learning, access was limited, and university resources were not always recognised or effective. The findings have implications for the design of effective graduate employability initiatives.  相似文献   
90.
This longitudinal study of 105 economically disadvantaged children examined the relation between reading problems and internalizing behavior in 3rd- and 5th-grade assessments (8- to 12-year olds). The variable-centered results showed that reading problems predicted change in internalizing behavior in the context of child and family predictors. The person-centered results showed that children with reading problems in both grades had higher internalizing scores in 5th grade but not in 3rd grade than children with reading problems in 3rd grade or no problems. Child-reported negative emotion experiences varied similarly across grade. The results tie reading problems to emotional distress in school and support conclusions about the direction of effects and the internalization of academic difficulty for disadvantaged children.  相似文献   
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