Millimeter wave satellite communication studies. Results of the 1981 propagation modeling effort

Theoretical modeling associated with rain effects on millimeter wave propagation is detailed. Three areas of work are discussed. A simple model for prediction of rain attenuation is developed and evaluated. A method for computing scattering from single rain drops is presented. A complete multiple scattering model is described which permits accurate calculation of the effects on dual polarized signals passing through rain

Longitudinal Invariance of the Center for Epidemiologic Studies-Depression Scale among Girls and Boys in Middle School

This study tested the longitudinal factorial invariance of a theoretically consistent, higher-order model for Center for Epidemiologic Studies-Depression (CES-D) scores among adolescent girls and boys in middle school. Data were collected from 2,416 adolescents who completed a survey containing the CES-D in the fall of 1998, spring of 1999, and spring of 2000. The invariance analyses were conducted using LISREL 8.50 with maximum likelihood estimation and the Satorra-Bentler scaled chi-square statistic and standard errors. The higher-order model demonstrated longitudinal, as well as gender, invariance of the overall factor structure and first- and second-order structure coefficients, first-order factor variances, second-order factor variances, and covariances, and item uniquenesses. The results demonstrate that meaningful comparisons of composite CES-D scores can be made across time among girls and boys in middle school

Effects of chronic exercise on feelings of energy and fatigue: A quantitative synthesis

The authors investigated the effect of chronic exercise on feelings of energy and fatigue using metaanalytic techniques. Chronic exercise increased feelings of energy and lessened feelings of fatigue compared with control conditions by a mean effect delta of 0.37. The effect varied according to the presence or absence of a placebo control or whether chronic exercise was completed alone or in combination with an additional therapy. Investigations that used a placebo control and examined chronic exercise alone found no effect of chronic exercise on feelings of energy and fatigue. Certain placebo controls may increase feelings of energy and lessen feelings of fatigue when used with older adults or people with psychological distress. The results highlight the need for research identifying the most useful control conditions for accurately interpreting mental health outcome data obtained in chronic exercise investigations

Scale Development for Perceived School Climate for Girls’ Physical Activity

Objectives: To test an original scale assessing perceived school climate for girls\u27 physical activity in middle school girls. Methods: Confirmatory factor analysis (CFA) and structural equation modeling (SEM). Results: CFA retained 5 of 14 original items. A model with 2 correlated factors, perceptions about teachers\u27 and boys\u27 behaviors, respectively, fit the data well in both sixth and eighth-graders. SEM detected a positive, significant direct association of the teacher factor, but not the boy factor, with girls\u27 self-reported physical activity. Conclusions:School climate for girls\u27 physical activity is a measurable construct, and preliminary evidence suggests a relationship with physical activity

Scale Development for Perceived School Climate for Girls’ Physical Activity

Objectives: To test an original scale assessing perceived school climate for girls\u27 physical activity in middle school girls. Methods: Confirmatory factor analysis (CFA) and structural equation modeling (SEM). Results: CFA retained 5 of 14 original items. A model with 2 correlated factors, perceptions about teachers\u27 and boys\u27 behaviors, respectively, fit the data well in both sixth and eighth-graders. SEM detected a positive, significant direct association of the teacher factor, but not the boy factor, with girls\u27 self-reported physical activity. Conclusions: School climate for girls\u27 physical activity is a measurable construct, and preliminary evidence suggests a relationship with physical activity

Self-Management Strategies Mediate Self-Efficacy and Physical Activity

Self-efficacy theory proposes that girls who have confidence in their capability to be physically active will perceive fewer barriers to physical activity or be less influenced by them, be more likely to pursue perceived benefits of being physically active, and be more likely to enjoy physical activity. Self-efficacy is theorized also to influence physical activity through self-management strategies (e.g., thoughts, goals, plans, and acts) that support physical activity, but this idea has not been empirically tested

Relationship between psychological and biological factors and physical activity and exercise behaviour in Filipino students

The aim of the present study was threefold. Firstly, it investigated whether a general measure or specific measure of motivational orientation was better in describing the relationship between motivation and exercise behaviour. Secondly, it examined the relationship between the four most popular indirect methods of body composition assessment and physical activity and exercise patterns. Thirdly, the interaction between motivation and body composition on physical activity and exercise behaviour was explored in a sample of 275 Filipino male and female students. Males were found to have higher levels of exercise whereas females had higher levels of physical activity. Furthermore, general self-motivation together with body weight and percentage body fat were found to be the best predictor of exercise behaviour whereas the tension/pressure subscale of the ‘Intrinsic Motivation Inventory’ (IMI) was the best predictor of levels of physical activity. However, significant gender differences were observed. That is, for the males only self-motivation and for the females only body weight and BMI predicted exercise behaviour. Also, tension/pressure predicted physical activity levels for the females but not the males. No inverse relationship was found between the four body composition measures and exercise and physical activity behaviour. The results support the notion that the psychobiological approach might be particularly relevant for high intensity exercise situations but also highlights some important gender differences. Finally, the results of this study emphasise the need for more cross-cultural research

Weight, physical activity and dietary behavior change in young mothers : short term results of the HeLP-her cluster randomized controlled trial

BackgroundPreventing weight gain rather than treating established obesity is an important economic and public health response to the rapidly increasing rates of obesity worldwide. Treatment of established obesity is complex and costly requiring multiple resources. Preventing weight gain potentially requires fewer resources to reach broad population groups, yet there is little evidence for successful interventions to prevent weight gain in the community. Women with children are an important target group because of high rates of weight gain and the potential to influence the health behaviors in family members.MethodsThe aim of this cluster randomized controlled trial was to evaluate the short term effect of a community-based self-management intervention to prevent weight gain. Two hundred and fifty mothers of young children (mean age 40 years &plusmn; 4.5, BMI 27.9 kg/m2 &plusmn; 5.6) were recruited from the community in Melbourne, Australia. The intervention group (n = 127) attended four interactive group sessions over 4 months, held in 12 local primary schools in 2006, and was compared to a group (n = 123) receiving a single, non-interactive, health education session. Data collection included self-reported weight (both groups), measured weight (intervention only), self-efficacy, dietary intake and physical activity.ResultsMean measured weight decreased significantly in the intervention group (-0.78 kg 95% CI; -1.22 to -0.34, p &lt; 0.001). Comparing groups using self-reported weight, both the intervention and comparison groups decreased weight, -0.75 kg (95% CI; -1.57 to 0.07, p = 0.07) and -0.72 kg (95% CI; -1.59 to 0.14 p = 0.10) respectively with no significant difference between groups (-0.03 kg, 95% CI; -1.32 to 1.26, p = 0.95). More women lost or maintained weight in the intervention group. The intervention group tended to have the greatest effect in those who were overweight at baseline and in those who weighed themselves regularly. Intervention women who rarely self-weighed gained weight (+0.07 kg) and regular self-weighers lost weight (-1.66 kg) a difference of -1.73 kg (95% CI; -3.35 to -0.11 p = 0.04). The intervention reported increased physical activity although the difference between groups did not reach significance. Both groups reported replacing high fat foods with low fat alternatives and self-efficacy deteriorated in the comparison group only.ConclusionBoth a single health education session and interactive behavioral intervention will result in a similar weight loss in the short term, although more participants in the interactive intervention lost or maintained weight. There were small non-significant changes to physical activity and changes to fat intake specifically replacing high fat foods with low fat alternatives such as fruit and vegetables. Self-monitoring appears to enhance weight loss when part of an intervention.<br /

Seven HCI Grand Challenges

This article aims to investigate the Grand Challenges which arise in the current and emerging landscape of rapid technological evolution towards more intelligent interactive technologies, coupled with increased and widened societal needs, as well as individual and collective expectations that HCI, as a discipline, is called upon to address. A perspective oriented to humane and social values is adopted, formulating the challenges in terms of the impact of emerging intelligent interactive technologies on human life both at the individual and societal levels. Seven Grand Challenges are identified and presented in this article: Human-Technology Symbiosis; Human-Environment Interactions; Ethics, Privacy and Security; Well-being, Health and Eudaimonia; Accessibility and Universal Access; Learning and Creativity; and Social Organization and Democracy. Although not exhaustive, they summarize the views and research priorities of an international interdisciplinary group of experts, reflecting different scientific perspectives, methodological approaches and application domains. Each identified Grand Challenge is analyzed in terms of: concept and problem definition; main research issues involved and state of the art; and associated emerging requirements