48 resultados para Three-body resonances


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A new instrument, the Body Change Inventory, was developed to provide an assessment of body change strategies that are used by both adolescent girls and boys. The novel aspect of this instrument is that it evaluates strategies to increase body size and increase muscle size, as well strategies to decrease body size. Independent samples of adolescent girls and boys aged between 11 and 17 years (N=1732) participated in four studies. The revised instrument consisted of three body change scales—Strategies to Decrease Body Size, Strategies to Increase Body Size, and Strategies to Increase Muscle Size. The studies demonstrated content validity, construct validity, internal consistency, and concurrent and discriminant validity for the new scales. The new scales provide a valuable addition in the literature for assessing three global body change strategies among adolescent girls and boys. They are needed in order to examine further the normative development of different kinds of body change strategies and how these may lead to behavioural problems such as disordered eating, exercise dependence, and steroid use.

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Although past studies have highlighted fat talk as relevant to body image disturbance, the majority of these have only investigated the link between fat talk and body esteem, to the exclusion of other body image constructs. One hundred and ninety-nine women completed an online survey measuring levels of appearance-based comparisons, body surveillance, thin ideal internalization, body esteem, and fat talk (FT-body concerns and FT-body comparisons). Results showed that fat talk made a significant contribution in explaining additional variance in body esteem above the other three body image factors, with FT-body concerns in particular making the highest unique contribution. Hierarchical regression analyses suggest that fat talk should be viewed as an independent psychosocial predictor of body esteem in both theoretical and therapeutic contexts. Future research should explore these relationships from a longitudinal perspective, and also clarify the nuances in the relationships by investigating the nature of women's everyday body image experiences.

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Predators exert strong selection pressures on their prey. Prey would therefore benefit by adjusting their behaviour to the risk of predation, while predators conversely would benefit from adjusting their behaviour to that of their prey. Extravagant ornamentation has evolved to attract mates and/or successfully compete with conspecifics of the same sex to secure high mating success, even if that occurs at a cost of increased risk of predation. Thus, sexually dichromatic species may be more susceptible to predation than sexually monochromatic species, and the presence of compensation is indicative of such species being more vulnerable. If extravagant ornamentation is costly in terms of predation risk, then we should expect sexually dichromatic species to have longer flight initiation distances (FID) than sexually monochromatic species. If ornamentation is acquired as a handicap with only individuals in prime condition being able to display with the smallest viability cost, we should expect sexually dichromatic individuals to have shorter FID than sexually monochromatic individuals. Such differences among individuals should, on an evolutionary time scale, translate into differences in FID being related to differences in sexual dichromatism among species. We investigated the relationship between FID and sexual dichromatism in phylogenetic analyses, while accounting for effects of continent (Australia, North America, and Europe), body mass, the interaction between sexual dichromatism and body mass and the interaction between sexual dichromatism and continent. In an analysis of 447 species we found shorter FID in sexually dichromatic than in sexually monochromatic species (consistent with the handicap hypothesis because sexually dichromatic species took greater risks), especially so at large body size. FID differed among continents and the relative difference in FID between sexually monochromatic and sexually dichromatic species was larger in Europe than in Australia and North America. These differences among continents may be attributed to latitudinal effects of predation. These findings are important for current ideas about the evolution of secondary sexual characters because they imply covarying continental differences in predation, especially for large bodied sexually dichromatic species.

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This article is concerned with the development and evaluation of the Perceived Sociocultural Influences on Body Image and Body Change Questionnaire. The scale was designed to assess the perceived nature of feedback received from mother, father, best male friend, and best female friend to gain weight, lose weight, and increase muscle tone. The perceived feedback from the media on each of these areas also was assessed. Exploratory factor analysis was conducted with 240 adolescent boys (mean age = 13.83 years) and 204 adolescent girls (mean age = 13.70 years). A 3-factor structure was found for the 4 scales that related to perceived feedback from mother, father, best male friend, and best female friend. Feedback on muscle tone loaded with both weight loss and weight gain. The three factors related to (a) general feedback; (b) encourage, tease, and modeling to gain weight and increase muscle tone, and (c) encourage, tease, and modeling to lose weight and increase muscle tone. The factor structure and the items that made up these factors were the same for both boys and girls for each of the 4 scales. The Perceived Media Influences Scale formed 3 factors for girls. These factors related to gaining weight, losing weight, and increasing muscle tone. For boys, the same 9 items formed a single factor. The same items were retained for boys and girls. A confirmatory factor analysis with 822 adolescents (382 boys, mean age = 14.02 years; 440 girls, mean age = 13.82 years) confirmed the previously described factor structure. These results demonstrate that the Perceived Sociocultural Influences on Body Image and Body Change Questionnaire is able to assess body image and body change strategies that are relevant for both boys and girls.

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OBJECTIVES: To determine the relationship between lower body strength of community-dwelling older adults and the time to negotiate obstructed gait tasks.

DESIGN: A correlational study.

SETTING: The Biomechanics Laboratory, Deakin University, Australia.

PARTICIPANTS: Twenty-nine women and 16 men aged 62 to 88 were recruited using advertisements placed in local newspapers. The participants were independent community dwellers, healthy and functionally mobile.

MEASUREMENTS: Maximal isometric strength of the knee extensors and dynamic strength of the hip extensors, hip flexors, hip adductors, hip abductors, knee extensors, knee flexors, and ankle plantar flexors were assessed. The times to negotiate four obstructed gait tasks at three progressively challenging levels on an obstacle course and to complete the course were recorded. The relationship between strength and the crossing times was explored using linear regression models.

RESULTS: Significant associations between the seven strength measures and the times to negotiate each gait task and to walk the entire course at each level were obtained (r = -0.38 to -0.55; P < .05). In addition, the percentage of the variance explained by strength (R2), consistently increased as a function of the progressively challenging level. This increase was particularly marked for the stepping over task (R2 = 19.3%,25.0%, and 27.2%, for levels 1, 2, and 3, respectively) and the raised surface condition (R2 = 17.1%,21.1%, and 30.8%, for levels 1,2, and 3, respectively) .

CONCLUSION:
The findings of the study showed that strength is a critical requirement for obstructed locomotion. That the magnitude of the association increased as a function of the challenging levels suggests that intervention programs aimed at improving strength would potentially be effective in helping community-dwelling older adults negotiate environmental gait challenges.

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Five types of aquatic food industry waste products (carp offal, carp roe, fish frames, trout offal and surimi processing waste) together with fish meal were evaluated for their suitability as potential fish meal replacements, partially or wholly, in diets for three species (rainbow trout, Murray cod and shortfin eel) cultured in Australia, using a number of criteria.

The proximate composition of the ingredients on a dry matter basis including protein content, lipid and ash, varied considerably. The essential amino acid (EAA) contents of the waste products and fish meal decreased in the order: carp roe > fish meal > carp offal > 'surimi' processing waste > fish frames > trout offal. The results of cluster analysis of A/E ratios of waste products and fish whole body fell within three clusters. The EAAI of whole body tissue of Murray cod, rainbow trout and Australian shortfin eel however, were closest to fish meal, followed by fish frame waste and/or 'surimi' waste. The results on A/E ratios and EAAI did not conform to the raw data on TAA and EAA. Therefore, the study emphasizes the need to have a multi-prong approach to determine the suitability of ingredients for incorporation into fish feeds.

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The present study was designed to develop a Body Modification Scale (BMS) to measure body change among adolescents and to modify an Excessive Exercise Scale (EES) into a shorter form for adolescents. Two hundred and twenty-one girls and 192 boys from Grades 7 to 10 completed the BMS and the EES. Factor analysis revealed three identical factors for the BMS for girls and boys: weight loss, weight gain, and muscle mass. Two identical factors for girls and boys were also revealed for the EES. Both factor structures were further validated on a separate sample of 286 adolescents (140 girls, 146 boys). The BMS and EES demon-strated excellent reliability (alpha > .86) and high test-retest reliability (alpha > .82) over 1 month. Good concurrent validity was also found for the weight loss factor of the BMS. These findings demonstrate the utility of these two scales for use with adolescents.

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The current study used qualitative methodology to investigate the body image concerns of people with physical disabilities. Three males and four females aged between 22 and 50 years, in Melbourne, Australia, participated in the study. Three participants were heterosexual, two were homosexual and two described their sexual identity as predominantly heterosexual but ‘bicurious’. The data were gathered through individual interviews of approximately 2 h duration, where participants responded to a set of predetermined open-ended questions. The study found that bodily impairment had a negative influence on the participants’ psychological experiences, feelings and attitudes toward their own bodies. The impact of feedback from the social environment was highlighted, and there was evidence suggesting that individuals gradually adjust to their different bodies and increasingly accept their disabilities over time.

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Objective: Most past research has focused on body dissatisfaction among females. This paper provides a review and evaluation of studies that have examined body dissatisfaction among males. Body dissatisfaction in males has been associated with poor psychological adjustment, eating disorders, steroid use, exercise dependence, as well as other health behaviors. It is therefore important to understand the level of body dissatisfaction, as well as the factors that are related to this construct. Method: The review is divided into three sections: body dissatisfaction among children, adolescents and adults. Within each section, levels of body dissatisfaction are examined, as well as the research that relates to sociocultural influences on body dissatisfaction. Difficulties in drawing valid conclusions from the data due to methodological problems are highlighted. Results: From the current data, it would appear that there are strong similarities in the levels of body dissatisfaction of male and female children, with most children demonstrating high levels of body satisfaction. During adolescence, boys are about equally divided between wanting to lose weight and increasing weight, but there are few studies that have examined a desire for increased muscle size. In adulthood, men evidence a stronger desire to lose weight as they get older. Conclusion: Overall, past studies have primarily focused on questions that are relevant to females, and there is a need to conduct studies that evaluate areas of body dissatisfaction that have greater relevance for males. This will then allow a better understanding of the relationship between body dissatisfaction and psychological and behavioral problems experienced by males at all stages of the lifespan.

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OBJECTIVES: (1) To study the relationship between quality of life (QoL) and measured and perceived weight and dieting history in Dutch men and women; (2) to assess the effect of weight loss over a 5 y period on QoL.

DESIGN: A cross-sectional study, in a sub-sample longitudinal over 5 y.

SUBJECTS:
A total of 2155 men and 2446 women, aged 20-59 and recruited from the general population from three towns in The Netherlands.

MEASUREMENTS: Body weight, height, self-administered questionnaire including questions concerning demographic variables and weight loss practices as part of the Dutch Monitoring project on Risk Factors for Chronic Disease (MORGEN). The Rand-36 questionnaire was used as the QoL measure.

RESULTS: In men, measured overweight (body mass index, BMI>25 kg=m2) was not associated with any dimension of QoL after adjustment for age, educational level and perceived overweight. Perceived overweight was related to reduced scores for general health and vitality. This relationship was independent of measured obesity. A history of repeated weight loss was associated with reduced scores for role functioning due to both physical and emotional problems. In women, measured overweight was significantly associated with lower scores for five out of eight QoL dimensions and perceived overweight with three: general health, vitality and physical functioning. A history of frequent weight loss was related to significantly reduced scores in six dimensions. However, only with history of frequent weight loss, and uniquely in women, was there a significant reduction in
scores on mental health and limited emotional role functioning. Measured and perceived overweight and frequent weight loss were all related to reduced scores for physical functioning. Longitudinal data indicate that in older women weight gain of 10% body weight or more was associated with a significant deterioration in QoL.

CONCLUSIONS: When looking at measures of QoL in relation to overweight it is important to separate the effects of perception of weight status and history of weight loss. We observed that the latter two factors were associated with reduced scores on several dimensions of QoL, particularly in women. These associations were observed to be independent of body weight. International Journal of Obesity (2001) 25, 1386 – 1392

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Objective: We explored the extent to which changes in emotional states following exposure to images of idealized bodies predict unhealthy body change attitudes and behaviors in women and men, and whether particular psychological traits mediate these effects. Method: One hundred thirty-three women and 93 men were assessed for unhealthy attitudes and behaviors related to body weight and muscles using the Eating Disorder Inventory-2 (EDI-2), the Obligatory Exercise Questionnaire, and the strategies to increase muscles subscale of the Body Change Inventory. Psychological traits assessed included body dissatisfaction (EDI-2), internalization of the thin/athletic ideal (Sociocultural Attitudes Towards Appearance Questionnaire-3), body comparison (Body Comparison Scale), self-esteem (Rosenberg Self-Esteem Inventory), depression (Beck Depression Inventory-II), and identity confusion (Self-Concept Clarity Scale). Participants were then exposed to photographs of thin female models and muscular male models, and visual analogue scales were used to measure changes in postexposure state body dissatisfaction, anger, anxiety, and depression.
Results: Postexposure increases in state anger, anxiety, depression, and body dissatisfaction correlated with drive for thinness and disordered eating symptomatology in women, while postexposure increases in state body dissatisfaction correlated with muscle development in men. Analyses revealed that internalization and body comparison mediated these relationships, with trait body dissatisfaction, trait depression, self-esteem, and self-concept/identity confusion serving as mediators for women only. Conclusion: These results are indicative of gender differences in: (a) reactions to idealized bodies; (b) psychological traits that predispose individuals to experience these reactions; and (c) types of body change behavior that are associated with these reactions.

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Background
While much cross-sectional data is available, there have been few longitudinal investigations of patterns of electronic media use in children. Further, the possibility of a bi-directional relationship between electronic media use and body mass index in children has not been considered. This study aimed to describe longitudinal patterns of television viewing and electronic game/computer use, and investigate relationships with body mass index (BMI).
Methods
This prospective cohort study was conducted in elementary schools in Victoria, Australia. 1278 children aged 5–10 years at baseline and 8–13 years at follow-up had their BMI calculated, from measured height and weight, and transformed to z-scores based on US 2000 growth data. Weight status (non-overweight, overweight and obese) was based on international BMI cut-off points. Weekly television viewing and electronic game/computer use were reported by parents, these were summed to generate total weekly screen time. Children were classified as meeting electronic media use guidelines if their total screen time was ≤14 hrs/wk.
Results
Electronic media use increased over the course of the study; 40% met guidelines at baseline but only 18% three years later. Television viewing and electronic game/computer use tracked moderately and total screen time was positively associated with adiposity cross-sectionally. While weaker relationships with adiposity were observed longitudinally, baseline z-BMI and weight status were positively associated with follow-up screen time and baseline screen time was positively associated with z-BMI and weight status at follow-up. Children who did not meet guidelines at baseline had significantly higher z-BMI and were more likely to be classified as overweight/obese at follow-up.

Conclusion
Electronic media use in Australian elementary school children is high, increases with age and tracks over time. There appears to be a bi-directional association suggesting that interventions targeting reductions in either screen time or adiposity may have a positive effect on both screen time and adiposity.

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Objective: To explore the relationship between family average income (FAI; an index of socio-economic status) and body mass index (BMI; a widely used, inexpensive indicator of weight status) above the healthy weight range in a region of Mainland China. Design: Population-based cross-sectional study, conducted between October 1999 and March 2000 on a sample of regular local residents aged 35 years or older who were selected by random cluster sampling. Setting: Forty-five administrative villages selected from three urban districts and two rural counties of Nanjing municipality, Mainland China, with a regional population of 5.6 million. Subjects: In total, 29 340 subjects participated; 67.7% from urban and 32.3% from rural areas; 49.8% male and 50.2% female. The response rate among eligible participants was 90.1%. Results: The proportion of participants classified as overweight was 30.5%, while 7.8% were identified as obese. After adjusting for possible confounding variables (age, gender, area of residence, educational level, occupational and leisure-time physical activity, daily vegetable consumption and frequency of red meat intake), urban participants were more likely to be overweight or obese relative to their rural counterparts, more women than men were obese, and participants in the lowest FAI tertile were the least likely to be above the healthy weight range. Conclusions: The proportion of adults with BMI above the healthy weight range was positively related to having a higher socio-economic status (indexed by FAI) in a regional Chinese population.

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The current study was conducted to investigate the relationships between body size estimations and disordered eating symptomatology. The method of constant stimuli was used to derive three measures of self-perceived body size in 93 women: (1) accuracy of body size estimations (body image distortion); (2) sensitivity in discriminating body size within blocks of trials (body image sensitivity); and (3) variability in making body size estimations between blocks of trials (body image variability). Participants also completed measures of disordered eating. Although body image distortion correlated with dietary restraint and eating concern, body image variability accounted for additional variance in these variables, as well as variance in binge eating. The relationships involving body image variability were found to be mediated by body dissatisfaction and internalization of the thin ideal. Together, these results are consistent with the proposition that body image variability is a significant factor in disordered eating.

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Objective. To assess associations between multiple potential predictors and change in child body mass index (BMI). Methods.In the 1997 Health of Young Victorians Study, children in Grades preparatory to three (aged 510 years) had their height and weight measured. Parents provided information on potential predictors of childhood overweight across six domains (children’s diet, children’s activity level, family composition, sociodemographic factors, prenatal factors and parental adiposity). Measures were repeated three years later in 2000/1. BMI was transformed to standardised (z) scores using the US 2000 Growth Chart data and children were classified as non-overweight or overweight according to international cutpoints.Regression analyses, including baseline BMI z-score as a covariate, assessed the contribution of each potential predictor to change in BMI z-score, development of overweight and spontaneous resolution of overweight in 1 373 children.Results. BMI z-score change was positively associated with frequency of take-away food, food quantity, total weekly screen time, non-Australian paternal country of birth, maternal smoking during pregnancy, and maternal and paternal BMI.Inverse associations were noted for the presence of siblings and rural residence (all pB0.05). Predictors of categorical change (development and resolution of overweight) were less clearly identified, apart from an association between maternal BMI and overweight development (p0.02). Multivariable models suggested individual determinants have a cumulative effect on BMI change. Conclusions. Strong short-term tracking of BMI makes it difficult to identify predictors of change. Nonetheless, putative determinants across all domains assessed were independently associated with adiposity change. Multi-faceted solutions are likely to be required to successfully deal with the complexities of childhood overweight.