塔里木盆地水土资源开发及其生态环境效应

塔里木河盆地人口与经济发展而带来的水土资源开发利用程度的增加 ,对盆地生态环境产生了重大的影响。由于上游水土资源开发面积急剧增加 ,导致支流向干流输水逐年减少、年内分配趋于集中、引水口猛增导致干流下游河段断流等水文现象。塔里木盆地水土资源开发到来的效应有积极建设性的一面 ,也有消极的破坏原有生态环境的一面。积极一面主要表现在 :①人工绿洲面积扩大 ,绿洲内部小气候条件改善 ;②土地生产能力提高 ;③水资源有效利用率提高 ;④绿洲内部结构更加完善、趋于稳定等。消极一面主要表现在 :①天然绿洲植被衰退 ;②土地沙漠化和沼泽化、盐渍化并存 ;③河流水质恶化、下游地下水位下降等。塔里木河流域水土资源开发的同时要重视生态环境建设与调控具有重要意义     

Pole length affects cross-country skiers’ performance in an 80-m double poling trial performed on snow from standing start

We investigated the hypothesis that longer and shorter poles would be faster and slower, respectively, than poles of self-selected length in all-out double poling. Eight elite cross-country skiers performed 80 m all-out double poling on snow performed from a standing start. Three trials with each of the pole lengths: self-selected, 7.5 cm shorter, and 7.5 cm longer than self-selected were performed. Time was recorded every 20 m and skiers were filmed during the last 40 m for calculation of cycle rate and length. Times at 80 m were 0.9 ± 0.7% shorter with longer poles than with self-selected poles (p ≤ 0.05), while they were 1.2 ± 1.0% slower with shorter poles (p ≤ 0.05). Much of these differences were established within the first 20 m. Calculated lead at 80 m with longer poles was 0.88 ± 0.65 m over self-selected poles (p ≤ 0.05). Mean cycle rate and length ranged from 1.35 to 1.45 Hz and from 4.84 to 5.52 m, respectively, across pole lengths (p > 0.05).     

Körperbild und Körperzufriedenheit im Leistungssport

The controversy surrounding the role of competitive sports in the development of eating disorders has increased in recent decades. There are inconsistent findings in the literature concerning the relationship between eating disorders and competitive sports, especially aesthetic sports. The aim of this study was therefore to assess eating disorder-related psychopathology in a sample of competitive figure skaters (FS) representative for competitive aesthetic sports. Special attention is paid to the investigation of body image and body satisfaction. Patients with anorexia nervosa (AN) and a healthy control group (CG) served as comparison groups. None of the FS met the complete diagnostic criteria for an eating disorder. Furthermore no significant differences were observed between the FS and the CG regarding body image and body satisfaction. However, a significant difference was detected compared to the AN patients. Our results underline the necessity for a differentiated analysis and careful diagnostics of sport-specific aspects when considering eating disorder-related psychopathology in competitive sports.     

Seated versus standing position for maximization of performance during intense uphill cycling

It is not known whether the seated or standing position favours performance during intensive bouts of uphill cycling. The following hypotheses were therefore tested: (1) the standing position results in better performance at a high power output, while (2) the seated position is best at a moderate power output. We also assessed the seated-standing transition intensity, above which seated cycling should be superseded by standing cycling for maximization of performance. Ten male cyclists (mean age 27 years, s = 3; height 1.82 m, s = 0.07; body mass 75.2 kg, s = 7.0; VO2max 70.0 ml.kg(-1).min(-1), s = 5.2) performed seated and standing treadmill cycling to exhaustion at 10% grade and at four power outputs ranging from 86% to 165% of their power output at maximal oxygen uptake (Wmax). Power output at maximal oxygen uptake was obtained during determination of VO2max. There was no difference in time to exhaustion between the two cycling positions at 86% of Wmax (P = 0.29). All participants performed best at the highest power output (165% of Wmax) when standing (P = 0.002). An overall seated-standing transition intensity of 94% of Wmax was identified. Thus, in general, cyclists may choose either the standing or seated position for maximization of performance at a submaximal intensity of 86% of Wmax, while the standing position should be used at intensities above 94% of Wmax and approaching 165% of Wmax.     

Early childhood educators’ use of natural outdoor settings as learning environments: an exploratory study of beliefs,practices, and barriers

In efforts to encourage use of natural outdoor settings as learning environments within early childhood education, survey research was conducted with 46 early childhood educators from northern Minnesota (United States) to explore their beliefs and practices regarding natural outdoor settings, as well investigate predictors of and barriers to the educational use of these settings. Of the beliefs measured, only two were significantly related to frequency of use of natural outdoor settings: belief regarding difficulty in using natural outdoor settings and belief regarding their relationship to nature. The strongest predictor of use was belief regarding difficulty in using natural outdoor settings, accounting for 67.7% of the variance in the regression model. Results indicate primary barriers to be lack of walking access to natural outdoor settings, lack of time, winter weather, and safety concerns. These findings suggest efforts to increase early childhood educators’ use of natural outdoor settings should not focus on influencing their beliefs about the value of using natural outdoor settings in early childhood education, but instead on reducing barriers, thereby making the use of these settings seem more feasible.     

Evaluating the effects of environmental education programming on connectedness to nature

With a growing movement to re-connect children to nature, an understanding of the ability of environmental education (EE) programs to foster connectedness to nature is needed. The purpose of this exploratory quantitative study is to determine the effect of seven EE programs on participants' connectedness to nature. Results from the 385 children who participated in this study suggest two of the programs may be associated with a significant increase in connectedness to nature; however, due to the limitations of the study and a potential ‘ceiling effect’ of high initial levels of connectedness, further research is needed.     

IN SEARCH OF MEANING: A REMINISCENCE PROGRAM FOR OLDER PERSONS

A pilot evaluation is reported of a reminiscence program aimed at increasing personal meaning. Fifty-seven older persons completed both a sentence completion questionnaire measuring personal meaning and a depression scale administered before and after the program. In comparison to a group from a representative survey that was matched on life contexts, the personal meaning profile of the intervention group was more negative and more focused on self. Hence, a group with impoverished meaning was participating in the program. After the intervention, the personal meaning profile was more positive, in particular with regard to self-evaluations and evaluations of social relations. The group that improved most on depression also improved most on personal meaning. Further research on the program is warranted.