Intraindividual allometric development of aerobic power in 8- to 16-year-old boys

Purpose: The aims of this study are two-fold: first, to analyze intraindividual allometric development of aerobic power of 73 boys followed at annual intervals from 8 to 16 yr, and second, to relate scaled aerobic power with level of habitual physical activity and biological maturity status. Methods: Peak (V) over dot O-2 (treadmill), height, and body mass were measured. Biological maturity was based on age at peak height velocity (PHV) and level of physical activity was based on five assessments between 11 and 15 yr and at 17 yr. Interindividual and intraindividual allometric coefficients were calculated. Multilevel modeling was applied to verify if maturity status and activity explain a significant proportion of peak (V) over dot O-2 after controlling for other explanatory characteristics. Results: At most age levels, interindividual allometry coefficients for body mass exceed k = 0.750. Intraindividual coefficients of peak (V) over dot O-2 by body mass vary widely and range from k' = 0,555 to k' = 1,178. Late maturing boys have smaller k' coefficients than early maturing boys. Conclusion: Peak (V) over dot O-2 is largely explained by body mass, but activity level and its interaction with maturity status contribute independently to peak (V) over dot O-2 even after adjusting for body mass.

Age and gender differences in objectively measured physical activity in youth

TROST. S. G., R. R. PATE, J. F. SALLIS, P. S. FREEDSON, W. C. TAYLOR, M. DOWDA, and J. SIRARD. Age and gender differences in objectively measured physical activity in youth. Med. Sci. Sports Ererc., Vol. 34, No. 2, pp. 350-355, 2002. Purpose: The purpose of this study was to evaluate age and gender differences in objectively measured physical activity (PA) in a population-based sample of students in grades 1-12. Methods: Participants (185 male, 190 female) wore a CSA 7164 accelerometer for 7 consecutive days. To examine age-related trends. students were grouped as follows: grades 1-3 (N = 90), grades 4-6 (N = 91), grades 7-9 (N = 96). and grades 10-12 (N = 92). Bouts of PA and minutes spent in moderate-to-vigorous PA (MVPA) and vigorous PA (VPA) were examined. Results: Daily MVPA and VPA exhibited a significant inverse relationship with grade level, with the largest differences occurring between grades 1d-3 and 4-6. Boys were more active than girls; however, for overall PA, the magnitudes of the gender differences were modest. Participation in continuous 20-min bouts of PA was low to nonexistent. Conclusion: Our results support the notion that PA declines rapidly during childhood and adolescence and that accelerometers are feasible alternatives to self-report methods in moderately sized population-level surveillance studies.

Escalation of Drug Use in Early-Onset Cannabis Users vs Co-twin Controls

Context Previous studies have reported that early initiation of cannabis (marijuana) use is a significant risk factor for other drug use and drug-related problems. Objective To examine whether the association between early cannabis use and subsequent progression to use of other drugs and drug abuse/dependence persists after controlling for genetic and shared environmental influences. Design Cross-sectional survey conducted in 1996-2000 among an Australian national volunteer sample of 311 young adult (median age, 30 years) monozygotic and dizygotic same-sex twin pairs discordant for early cannabis use (before age 17 years). Main Outcome Measures Self-reported subsequent nonmedical use of prescription sedatives, hallucinogens, cocaine/other stimulants, and opioids; abuse or dependence on these drugs (including cannabis abuse/dependence); and alcohol dependence. Results Individuals who used cannabis by age 17 years had odds of other drug use, alcohol dependence, and drug abuse/dependence that were 2.1 to 5.2 times higher than those of their co-twin, who did not use cannabis before age 17 years. Controlling for known risk factors (early-onset alcohol or tobacco use, parental conflict/separation, childhood sexual abuse, conduct disorder, major depression, and social anxiety) had only negligible effects on these results. These associations did not differ significantly between monozygotic and dizygotic twins. Conclusions Associations between early cannabis use and later drug use and abuse/dependence cannot solely be explained by common predisposing genetic or shared environmental factors. The association may arise from the effects of the peer and social context within which cannabis is used and obtained. In particular, early access to and use of cannabis may reduce perceived barriers against the use of other illegal drugs and provide access to these drugs.

Life transitions and changing physical activity patterns in young women

Background: Physical activity (PA) patterns are likely to change in young adulthood in line with changes in lifestyle that occur in the transition from adolescence to adulthood. The aim of this study was to ascertain whether key life events experienced by young women in their early twenties are associated with increasing levels of inactivity. Methods: This was a 4-year follow-up of 7281 participants (aged 18 to 23 years at baseline) in the Australian Longitudinal Study of Women's Health, with self-reported measures of PA, life events, body mass index (BMI), and sociodemographic variables. Results: The cross-sectional data indicated no change in PA between baseline (57% active) and follow-up (56% active). However, for almost 40% of the sample, PA category changed between baseline and follow-up, with approximately 20% of the women changing from being active to inactive, and another 20% changing from being inactive to active. After adjustment for age, other sociodemographic variables, BMI, and PA at baseline, women who reported getting married, having a first or subsequent child, or beginning paid work were more likely to be inactive at follow-up than those who did not report these events. Conclusions: The results suggest that life events such as getting married, having children, and starting work are associated with decreased levels of PA in young adult women. Strategies are needed to promote maintenance of activity at the time when most women experience these key life-stage transitions.

Physical Activity and Bone Mineral Accrual During Childhood and Adolescence

The epidemic that is osteoporosis has led to an increasing interest in bone mineral, and the factors that influence the levels of bone mineral, in recent years. While it is unrealistic to try and turn back the clock, a return to an increased level of physical activity may be an important consideration in terms of skeletal health. Peak bone mass is largely determined by heredity, but lifestyle and dietary patterns also influence the level of bone mineral accrued during the growing years. In this review, we summarize the evidence that vigorous weight-bearing physical activity and adequate calcium intake represent the best possibility for enhancing the attainment of an optimal level of bone mineral, within genetic limits.

Mulheres (in)subordinadas : o empoderamento feminino e suas repercussões nas ocorrências de violência conjugal

Neste trabalho, explora-se o modo como a compreensão e o desempenho dos papéis de gênero se relacionam às ocorrências de violência (física, psicológica e sexual) dos maridos contra as esposas. Quatro mulheres que apresentaram queixa na Delegacia de Defesa da Mulher contra as agressões físicas perpetradas por seus parceiros e que conviviam com eles foram entrevistadas utilizando-se um roteiro de entrevista, que recolheu dados pessoais e informações a respeito das concepções sobre homem, mulher e relacionamento conjugal/afetivo. As entrevistas foram processadas pelo software Alceste, sendo a Análise de Conteúdo utilizada para complementar a análise. Os dados revelam a coexistência de concepções tradicionais de gênero com ações de insubordinação dessas mulheres (trabalho assalariado, amizades, questionamento da vida sexual). Esses aspectos, sinalizadores do empoderamento das mulheres, relacionam-se à agressividade dos parceiros que, excluídos dos debates feministas e buscando proteger sua masculinidade, usam a violência para suprimir as manifestações femininas de poder.

Targeting lactate transport suppresses in vivo breast tumour growth

Background: Most cancers, including breast cancer, have high rates of glucose consumption, associated with lactate production, a process referred as “Warburg effect”. Acidification of the tumour microenvironment by lactate extrusion, performed by lactate transporters (MCTs), is associated with higher cell proliferation, migration, invasion, angiogenesis and increased cell survival. Previously, we have described MCT1 up-regulation in breast carcinoma samples and demonstrated the importance of in vitro MCT inhibition. In this study, we performed siRNA knockdown of MCT1 and MCT4 in basal-like breast cancer cells in both normoxia and hypoxia conditions to validate the potential of lactate transport inhibition in breast cancer treatment. Results: The effect of MCT knockdown was evaluated on lactate efflux, proliferation, cell biomass, migration and invasion and induction of tumour xenografts in nude mice. MCT knockdown led to a decrease in in vitro tumour cell aggressiveness, with decreased lactate transport, cell proliferation, migration and invasion and, importantly, to an inhibition of in vivo tumour formation and growth. Conclusions: This work supports MCTs as promising targets in cancer therapy, demonstrates the contribution of MCTs to cancer cell aggressiveness and, more importantly, shows, for the first time, the disruption of in vivo breast tumour growth by targeting lactate transport.

Desesperança e agressividade na adolescência e qualidade de vinculação aos pais

RESUMO: As relações que constituímos com aqueles que de mais perto nos rodeiam são uma das partes, senão a parte mais relevante da nossa vida (Canavarro, 1999). Assim, a teoria da vinculação coloca grande ênfase na natureza da relação de vinculação (Bowlby, 1979). No primeiro capítulo é elucidado o modelo de desenvolvimento da vinculação de Bowlby (1969/1982; 1988) e de Ainsworth e colaboradores (1978). No segundo capítulo são explicadas as mudanças que ocorrem na fase da adolescência. No terceiro capítulo, é destacado o padrão comportamental agressivo do adolescente, o qual se pode traduzir numa vinculação insegura (Almeida, 2000). Estas situações podem levar o sujeito a apresentar comportamentos de desesperança, conceito este que irá ser desenvolvido no quarto capítulo. Sendo o principal objectivo da investigação estudar em que medida a qualidade de vinculação aos pais e a estrutura familiar estão relacionadas com a desesperança e a agressividade nos adolescentes, conclui-se que o adolescente com uma história de vinculação insegura apresenta menos confiança, maior alienação e, consequentemente, maior desamparo e desesperança (Bowlby, 1969/1982, 1973; Bretherton & Waters, 1985). Relativamente à estrutura familiar, o estudo reporta que a coesão e a adaptabilidade estão correlacionadas positivamente com a confiança e negativamente com a alienação. ABSTRACT: The relationships that we form of those who surround us are closer to one party, if not the most important part of our lives (Canavarro, 1999). Thus, attachment theory places great emphasis on the nature of the attachment relationship (Bowlby, 1979). In the first chapter, is elucidated development model of the binding of Bowlby (1969/1982, 1988) and Ainsworth and colleagues (1978). The second chapter explains the changes that occur during adolescence. The third chapter is highlighted the behavioral patterns of aggressive adolescents, which may result in insecure attachment (Almeida, 2000). These situations can cause the subject to present behavior of hopelessness, that this concept will be developed in the fourth chapter. Since the main aim of the research study to what extent the quality of attachment to parents and family structure are related to hopelessness and aggression in teenagers, it is concluded that the adolescent with a history of insecure attachment have less trust, increased alienation and, consequently, greater helplessness and hopelessness (Bowlby, 1969/1982, 1973, Bretherton & Waters, 1985). With regard to family structure, the study reports that the cohesion and adaptability are positively correlated with the confidence and negatively with alienation.

Patterns of induced abortion in urban area of Southeastern region, Brazil

OBJECTIVE: To assess the behavior of induced abortion as a function of certain demographic variables, for the population of fertile women (15 to 49 years old) residing in the Vila Madalena subdistrict S. Paulo (Brazil). MATERIAL AND METHOD: Two population samples were selected. One sample, with 996 women, investigated the incidence of induced abortions during 1987, using the RRT. In the other, involving 1,004 women, the same information was detected through a conventional approach. In both samples, the induced abortion occurring during the reproductive life was recorded in direct fashion. Though this analysis refers only to information about past abortions, that is by 2,000 women -, it should be noted that it is exactly the RRT that lends credibility to the found or results given results. CONCLUSION: The analysis furnishes evidence showing that single women, young women between the ages of 15 and 19, women who have not had live births, women who have a number of children below the expected ideal, women who use contraceptive methods (especially inefficient ones) and women who do not have any restrictions as to abortion constitute the categories most inclined to resort to induced abortion. This grouping suggests the existence of interrelationships between categories, that is, each of these categories is probably composed primarily of the same women, those who are at the beginning of their reproductive lives.

Incidence rate and spatio-temporal clustering of type 1 diabetes in Santiago, Chile, from 1997 to 1998

OBJECTIVE: To estimate the incidence rate of type 1 diabetes in the urban area of Santiago, Chile, from March 21, 1997 to March 20, 1998, and to assess the spatio-temporal clustering of cases during that period. METHODS: All sixty-one incident cases were located temporally (day of diagnosis) and spatially (place of residence) in the area of study. Knox's method was used to assess spatio-temporal clustering of incident cases. RESULTS: The overall incidence rate of type 1 diabetes was 4.11 cases per 100,000 children aged less than 15 years per year (95% confidence interval: 3.06--5.14). The incidence rate seems to have increased since the last estimate of the incidence calculated for the years 1986--1992 in the metropolitan region of Santiago. Different combinations of space-time intervals have been evaluated to assess spatio-temporal clustering. The smallest p-value was found for the combination of critical distances of 750 meters and 60 days (uncorrected p-value = 0.048). CONCLUSIONS: Although these are preliminary results regarding space-time clustering in Santiago, exploratory analysis of the data method would suggest a possible aggregation of incident cases in space-time coordinates.

Intergenerational interaction in health promotion: a qualitative study in Brazil

OBJECTIVE: In 1994 a pilot intergenerational project was started in the city of Taguatinga, Brazil, to promote the well-being of both elderly and adolescent populations using reminiscence processes as a means of interaction. The purpose of the study is to evaluate the project from the participants' viewpoint and to improve the contribution of those age groups in building up social capital. METHODS: From November 1999 to April 2000 a qualitative study using focus groups technique was conducted. Using a discussion guide, 9 groups of students, ranging in age from 13 to 19 years old, and 3 groups of elderly aged 60 years and over were interviewed to collect data regarding their interaction before and after an intergenerational program. RESULTS: The main findings suggested a change in attitude of young people toward old age and elderly people. Participating elderly people reported improvement in their health status. For both age groups the findings suggested a better understanding between generations. CONCLUSIONS: It seems that reminiscence intergenerational activity contributes to building up mutual trust and reciprocity. These results seem to indicate this is an alternative for investing in social capital and improving participants' well-being. However, further work is needed to support these findings.

Influence of environmental temperature and humidity on the acute ventilatory response to exercise in asthmatic adolescents

Asthma is a chronic inflammatory disorder of the respiratory airways affecting people of all ages, and constitutes a serious public health problem worldwide (6). Such a chronic inflammation is invariably associated with injury and repair of the bronchial epithelium known as remodelling (11). Inflammation, remodelling, and altered neural control of the airways are responsible for both recurrent exacerbations of asthma and increasingly permanent airflow obstruction (11, 29, 34). Excessive airway narrowing is caused by altered smooth muscle behaviour, in close interaction with swelling of the airway walls, parenchyma retractile forces, and enhanced intraluminal secretions (29, 38). All these functional and structural changes are associated with the characteristic symptoms of asthma – cough, chest tightness, and wheezing –and have a significant impact on patients’ daily lives, on their families and also on society (1, 24, 29). Recent epidemiological studies show an increase in the prevalence of asthma, mainly in industrial countries (12, 25, 37). The reasons for this increase may depend on host factors (e.g., genetic disposition) or on environmental factors like air pollution or contact with allergens (6, 22, 29). Physical exercise is probably the most common trigger for brief episodes of symptoms, and is assumed to induce airflow limitations in most asthmatic children and young adults (16, 24, 29, 33). Exercise-induced asthma (EIA) is defined as an intermittent narrowing of the airways, generally associated with respiratory symptoms (chest tightness, cough, wheezing and dyspnoea), occurring after 3 to 10 minutes of vigorous exercise with a maximal severity during 5 to 15 minutes after the end of the exercise (9, 14, 16, 24, 33). The definitive diagnosis of EIA is confirmed by the measurement of pre- and post-exercise expiratory flows documenting either a 15% fall in the forced expiratory volume in 1 second (FEV1), or a ≥15 to 20% fall in peak expiratory flow (PEF) (9, 24, 29). Some types of physical exercise have been associated with the occurrence of bronchial symptoms and asthma (5, 15, 17). For instance, demanding activities such as basketball or soccer could cause more severe attacks than less vigorous ones such as baseball or jogging (33). The mechanisms of exercise-induced airflow limitations seem to be related to changes in the respiratory mucosa induced by hyperventilation (9, 29). The heat loss from the airways during exercise, and possibly its post-exercise rewarming may contribute to the exercise-induced bronchoconstriction (EIB) (27). Additionally, the concomitant dehydration from the respiratory mucosa during exercise leads to an increased interstitial osmolarity, which may also contribute to bronchoconstriction (4, 36). So, the risk of EIB in asthmatically predisposed subjects seems to be higher with greater ventilation rates and the cooler and drier the inspired air is (23). The incidence of EIA in physically demanding coldweather sports like competitive figure skating and ice hockey has been found to occur in up to 30 to 35% of the participants (32). In contrast, swimming is often recommended to asthmatic individuals, because it improves the functionality of respiratory muscles and, moreover, it seems to have a concomitant beneficial effect on the prevalence of asthma exacerbations (14, 26), supporting the idea that the risk of EIB would be smaller in warm and humid environments. This topic, however, remains controversial since the chlorified water of swimming pools has been suspected as a potential trigger factor for some asthmatic patients (7, 8, 20, 21). In fact, the higher asthma incidence observed in industrialised countries has recently been linked to the exposition to chloride (7, 8, 30). Although clinical and epidemiological data suggest an influence of humidity and temperature of the inspired air on the bronchial response of asthmatic subjects during exercise, some of those studies did not accurately control the intensity of the exercise (2, 13), raising speculation of whether the experienced exercise overload was comparable for all subjects. Additionally, most of the studies did not include a control group (2, 10, 19, 39), which may lead to doubts about whether asthma per se has conditioned the observed results. Moreover, since the main targeted age group of these studies has been adults (10, 19, 39), any extrapolation to childhood/adolescence might be questionable regarding the different lung maturation. Considering the higher incidence of asthma in youngsters (30) and the fact that only the works of Amirav and coworkers (2, 3) have focused on this age group, a scarcity of scientific data can be identified. Additionally, since the main environmental trigger factors, i.e., temperature and humidity, were tested separately (10, 28, 39) it would be useful to analyse these two variables simultaneously because of their synergic effect on water and heat loss by the airways (31, 33). It also appears important to estimate the airway responsiveness to exercise within moderate environmental ranges of temperature and humidity, trying to avoid extreme temperatures and humidity conditions used by others (2, 3). So, the aim of this study was to analyse the influence of moderate changes in air temperature and humidity simultaneously on the acute ventilatory response to exercise in asthmatic children. To overcome the above referred to methodological limitations, we used a 15 minute progressive exercise trial on a cycle ergometer at 3 different workload intensities, and we collected data related to heart rate, respiratory quotient, minute ventilation and oxygen uptake in order to ensure that physiological exercise repercussions were the same in both environments. The tests were done in a “normal” climatic environment (in a gymnasium) and in a hot and humid environment (swimming pool); for the latter, direct chloride exposition was avoided.

Is the offence the best defense? Influences of childhood experiences and paranoia in the aggression in Azorean youths

A ideação paranoide é um processo cognitivo e social que pode ser considerado normativo (e.g. sentimentos de desconfiança ocasionais) ou disfuncional, constituindo-se, neste ultimo caso, como um sintoma psicopatológico (e.g. delírios paranoides). Mesmo em níveis subclínicos, a ideação paranoide pode constituir um entrave para o bom funcionamento interpessoal, na medida em que o comportamento disruptivo que dela advém pode afetar todas as esferas de funcionamento do indivíduo (e.g. relações familiares, entre pares, profissionais e/ou académicas). O presente estudo explorará a influência dos estilos parentais e o papel mediador da ideação paranoide na agressividade durante a adolescência, bem como as implicações para a prevenção e intervenção em contextos clínicos e educacionais.

Paranoia in the General Population : a revised version of the General Paranoia Scale for adolescents

The aim of the current study was to validate the General Paranoia Scale for Portuguese Adolescents population (GPS-A). This scale assesses the paranoid ideation in non-clinical population. Results from a confirmatory factor analysis of the scale on 1218 youths confirmed an alternative model to the one-dimensional model proposed by Fenigstein and Vanable (1992) comprising three different dimensions (Mistrust thoughts, persecutory ideas and depreciation). This alternative model presented a good fit: χ2 (162)= 727.200, p = .000; CFI = .925; RMSEA = .054, P(rmsea ≤0.05) = .000; PCFI = .788; AIC = 863.200. All items presented adequate factor loadings (λij ≥0.5) and individual reliability ((λij)2 ≥0.25). Further data analysis on the scale revealed that the GPS-A is an adequate assessment tool for adolescents, with good psychometric characteristics and high internal consistency.

Characterization and predictors of paranoid ideation in youths

Trabalho apresentado em ICAP 2015: 17th International Conference on Applied Psychology, Session 13, Tokyo, Japan, May 28-29, 2015.