90 resultados para Age effect

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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PURPOSE To verify whether the relative age effects (RAEs) occur among young male and female Swiss alpine skiers of different age groups and performance levels. Additionally, the efficacy of normalizing performance in physical tests to height and body mass to attenuate RAEs eventually present was tested. METHODS The Swiss-Ski Power Test consists of anthropometric measures and physical tests for coordination and speed, endurance and strength and is used since 2004 to evaluate 11- to 19-years old Swiss competitive alpine skiers. We analysed the distribution of 6996 tests performed by 1438 male and 1031 female alpine skiers between 2004 and 2011 according to the athlete's relative age quartile (Q). Differences in anthropometric measures and performance in physical tests according to Q were assessed and the possibility of attenuating eventual RAEs on performance by normalization of results to height and body mass was tested. RESULTS RAEs were found among all female and male age groups, with no differences between age groups. While performance level did not affect RAE for male skiers, it influenced RAE among female skiers. RAEs also influenced results in all physical tests except upper limbs strength. Normalization of results to body mass attenuated most RAEs identified. CONCLUSION small RAEs are present among young Swiss competitive alpine skiers and should be taken into account in training and selection settings, avoiding the waste of possible future talents. When ranking junior athletes according to their performance in physical tests, normalization of results to body mass decreases the bias caused by RAEs.

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Background: Semantic memory processes have been well described in literature. However, the available findings are mostly based on relatively young subjects and concrete word material (e.g. tree). Comparatively little information exists about semantic memory for abstract words (e.g. mind) and possible age related changes in semantic retrieval. In this respect, we developed a paradigm that is useful to investigate the implicit (i.e. attentionindependent) access to concrete and abstract semantic memory. These processes were then compared between young and elderly healthy subjects. Methods: A well established tool for investigating semantic memory processes is the semantic priming paradigm, which consists both of semantically unrelated and related word pairs. In our behavioral task these noun-noun word pairs were further divided into concrete, abstract and matched pronounceable non-word conditions. With this premise, the young and elderly participants performed a lexical decision task: they were asked to press a choice of two buttons as an indication for whether the word pair contained a non-word or not. In order to minimize controlled (i.e. attention-dependent) retrieval strategies, a short stimulus onset asynchrony (SOA) of 150ms was set. Reaction time (RT) changes and accuracy to related and unrelated words (priming effect) in the abstract vs. concrete condition (concreteness effect) were the dependent variables of interest. Results and Discussion: Statistical analysis confirmed both a significant priming effect (i.e. shorter RTs in semantically related compared to unrelated words) and a concreteness effect (i.e. RT decrease for concrete compared to abstract words) in the young and elderly subjects. There was no age difference in accuracy. The only age effect was a commonly known general slowing in RT over all conditions. In conclusion, age is not a critical factor in the implicit access to abstract and concrete semantic memory.

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Intact cognitive abilities are fundamental for driving. Driving-relevant cognition may be affected in older drivers due to aging or cognitive impairment. The aim of this study was to investigate the effects of cognitive impairment on driving-relevant cognition in older persons. Performance in selective and divided attention, eye-hand-coordination, executive functions and the ability to regulate distance and speed of 18 older persons with CI-Group (cognitive impairment group) was compared to performance of older control group (18 age and gender-matched cognitively normal subjects) and young control group (18 gender-matched young subjects). The CI-Group showed poorer performance than the other two control groups in all cognitive tasks (significance level (p) < 0.001, effect size (partial η2) = 0.63). Differences between cognitively impaired and cognitively normal subjects were still significant after controlling for age (effect sizes from 0.14 to 0.28). Dual tasking affected performance of cognitively impaired subjects more than performance of the other two groups (p = 0.016, partial η2 = 0.14). Results show that cognitive impairment has age-independent detrimental effects on selective and divided attention, eye-hand-coordination, executive functions and the ability to regulate distance and speed. Largest effect sizes are found for reaction times in attention tasks.

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Early detection of psychosis is an important topic in psychiatry. Yet, there is limited information on the prevalence and clinical significance of high-risk symptoms in children and adolescents as compared to adults. We examined ultra-high-risk (UHR) symptoms and criteria in a sample of individuals aged 8-40 years from the general population of Canton Bern, Switzerland, enrolled from June 2011 to May 2014. The current presence of attenuated psychotic symptoms (APS) and brief intermittent psychotic symptoms (BLIPS) and the fulfillment of onset/worsening and frequency requirements for these symptoms in UHR criteria were assessed using the Structured Interview for Psychosis Risk Syndromes. Additionally, perceptive and non-perceptive APS were differentiated. Psychosocial functioning and current non-psychotic DSM-IV axis I disorders were also surveyed. Well-trained psychologists performed assessments. Altogether, 9.9% of subjects reported APS and none BLIPS, and 1.3% met all the UHR requirements for APS. APS were related to more current axis I disorders and impaired psychosocial functioning, indicating some clinical significance. A strong age effect was detected around age 16: compared to older individuals, 8-15-year olds reported more perceptive APS, that is, unusual perceptual experiences and attenuated hallucinations. Perceptive APS were generally less related to functional impairment, regardless of age. Conversely, non-perceptive APS were related to low functioning, although this relationship was weaker in those below age 16. Future studies should address the differential effects of perceptive and non-perceptive APS, and their interaction with age, also in terms of conversion to psychosis.

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Weight gain is often associated with smoking cessation and may discourage smokers from quitting. This study estimated the weight gained one year after smoking cessation and examined the risk factors associated with weight gain in order to identify socio-demographic groups at higher risk of increased weight after quitting. We analyzed data from 750 adults in two randomized controlled studies that included smokers motivated to quit and found a gradient in weight gain according to the actual duration of abstinence during follow-up. Subjects who were abstinent for at least 40 weeks gained 4.6 kg (SD = 3.8) on average, compared to 1.2 kg (SD = 2.6) for those who were abstinent less than 20 weeks during the 1-year follow-up. Considering the duration of abstinence as an exposure variable, we found an age effect and a significant interaction between sex and the amount of smoking before quitting: younger subjects gained more weight than older subjects; among light smokers, men gained more weight on average than women one year after quitting, while the opposite was observed among heavy smokers. Young women smoking heavily at baseline had the highest risk of weight gain after quitting.

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Paper I: Corporate aging and internal resource allocation Abstract Various observers argue that established firms are at a disadvantage in pursuing new growth opportunities. In this paper, we provide systematic evidence that established firms allocate fewer resources to high-growth lines of business. However, we find no evidence of inefficient resource allocation in established firms. Redirecting resources from high-growth to low-growth lines of business does not result in lower profitability. Also, resource allocation towards new growth opportunities does not increase when managers of established firms are exposed to takeover and product market threats. Rather, it seems that conservative resource allocation strategies are driven by pressures to meet investors’ expectations. Our empirical evidence, thus, favors the hypothesis that established firms wisely choose to allocate fewer resources to new growth opportunities as external pressures force them to focus on efficiency rather than novelty (Holmström 1989). Paper II: Corporate aging and asset sales Abstract This paper asks whether divestitures are motivated by strategic considerations about the scope of the firm’s activities. Limited managerial capacity implies that exploiting core competences becomes comparatively more attractive than exploring new growth opportunities as firms mature. Divestitures help stablished firms free management time and increase the focus on core competences. The testable implication of this attention hypothesis is that established firms are the main sellers of assets, that their divestiture activity increases when managerial capacity is scarcer, that they sell non-core activities, and that they return the divestiture proceeds to the providers of capital instead of reinvesting them in the firm. We find strong empirical support for these predictions. Paper III: Corporate aging and lobbying expenditures Abstract Creative destruction forces constantly challenge established firms, especially in competitive markets. This paper asks whether corporate lobbying is a competitive weapon of established firms to counteract the decline in rents over time. We find a statistically and economically significant positive relation between firm age and lobbying expenditures. Moreover, the documented age-effect is weaker when firms have unique products or operate in concentrated product markets. To address endogeneity, we use industry distress as an exogenous nonlegislative shock to future rents and show that established firms are relatively more likely to lobby when in distress. Finally, we provide empirical evidence that corporate lobbying efforts by established firms forestall the creative destruction process. In sum, our findings suggest that corporate lobbying is a competitive weapon of established firms to retain profitability in competitive environments.

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The goal of this study was to determine whether advanced age affects mortality and incidence of neurological injury in patients undergoing surgical repair with hypothermic circulatory arrest in acute and chronic thoracic aortic pathology.

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The evidence for an effect of breastfeeding on lung function is conflicting, in particular whether the effect is modified by maternal asthma.

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BACKGROUND: Elevated plasma levels of interleukin (IL)-6, C-reactive protein (CRP), and D-dimer belong to the biological alterations of the "frailty syndrome," defining increased vulnerability for diseases and mortality with aging. We hypothesized that, compatible with premature frailty, chronic stress and age are related in predicting inflammation and coagulation activity in Alzheimer caregivers. METHODS: Plasma IL-6, CRP, and D-dimer levels were measured in 170 individuals (mean age 73 +/- 9 years; 116 caregivers, 54 noncaregiving controls). Demographic factors, diseases, drugs, and lifestyle variables potentially affecting inflammation and coagulation were obtained by history and adjusted for as covariates in statistical analyses. RESULTS: Caregivers had higher mean levels of IL-6 (1.38 +/- 1.42 vs 1.00 +/- 0.92 pg/mL, p =.032) and of D-dimer (723 +/- 530 vs 471 +/- 211 ng/mL, p <.001) than controls had. CRP levels were similar between groups (p =.44). The relationship between caregiver status and D-dimer was independent of covariates (p =.037) but affected by role overload. Age accounted for much of the relationship with IL-6. After controlling for covariates, the interaction between caregiver status and age was significant for D-dimer (beta =.20, p =.029) and of borderline significance for IL-6 (beta =.17, p =.090). Post hoc regression analyses indicated that, among caregivers, age was significantly correlated with both D-dimer (beta =.50, p <.001) and IL-6 (beta =.38, p =.001). Among controls, however, no significant relationship was observed between age and either D-dimer or IL-6. CONCLUSIONS: The interaction between caregiving status and age for D-dimer and IL-6 suggests the possibility that older caregivers could be at risk of a more rapid transition to the frailty syndrome and clinical manifestations of cardiovascular diseases.

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BACKGROUND: Due to the predicted age shift of the population an increase in the number of patients with late AMD is expected. At present smoking represents the only modifiable risk factor. Supplementation of antioxidants in patients at risk is the sole effective pharmacological prevention. The aim of this study is to estimate the future epidemiological development of late AMD in Switzerland and to quantify the potential effects of smoking and antioxidants supplementation. METHODS: The modelling of the future development of late AMD cases in Switzerland was based on a meta-analysis of the published data on AMD-prevalence and on published Swiss population development scenarios until 2050. Three different scenarios were compared: low, mean and high. The late AMD cases caused by smoking were calculated using the "population attributable fraction" formula and data on the current smoking habits of the Swiss population. The number of potentially preventable cases was estimated using the data of the Age-Related Eye Disease Study (AREDS). RESULTS: According to the mean population development scenario, late AMD cases in Switzerland will rise from 37 200 cases in 2005 to 52 500 cases in 2020 and to 93 200 cases in 2050. Using the "low" and the "high" scenarios the late AMD cases may range from 49 500 to 56 000 in 2020 and from 73 700 to 118 400 in 2050, respectively. Smoking is responsible for approximately 7 % of all late AMD cases, i. e., 2600 cases in 2005, 3800 cases in 2020, 6600 cases in 2050 ("mean scenario"). With future antioxidant supplementation to all patients at risk another 3100 cases would be preventable until 2020 and possibly 23 500 cases until 2050. CONCLUSION: Due to age shift in the population a 2.5-fold increase in late AMD cases until 2050 is expected, representing a socioeconomic challenge. Cessation of smoking and supplementation of antioxidants to all patients at risk has the potential to reduce this number. Unfortunately, public awareness is low. These data may support health-care providers and public opinion leaders when developing public education and prevention strategies.

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Plates used for fracture fixation produce vascular injury to the underlying cortical bone. During the recovery of the blood supply, temporary osteoporosis is observed as a result of Haversian remodeling of the necrotic bone. This process temporarily reduces the strength of the bone. We tackled the postulate that quantitative differences exist between animal species, and in different bones within the same species, due to variations in the relative importance of the endosteal and periosteal blood supplies. Using implants scaled to the size of the bone, we found comparable cortical vascular damage in the sheep and in the dog, and in the tibia and femur of each animal. We observed a significant reduction in cortical vascular damage using plates that had a smaller contact area with the underlying bone. No significant difference in cortical vascular damage was noted in animals of different ages.

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Body composition changes with increasing age in men, in that lean body mass decreases whereas fat mass increases. Whether this altered body composition is related to decreasing physical activity or to the known age-associated decrease in growth hormone secretion is uncertain. To address this question, three groups of healthy men (n = 14 in each group), matched for weight, height and body mass index, were investigated using dual-energy X-ray absorptiometry, indirect calorimetry and estimate of daily growth hormone secretion [i.e. plasma insulin-like growth factor I (IGF-I-) levels]. Group 1 comprised young untrained subjects aged 31.0 +/- 2.1 years (mean +/- SEM) taking no regular physical exercise; group 2 consisted of old untrained men aged 68.6 +/- 1.2 years; and group 3 consisted of healthy old men aged 67.4 +/- 1.2 years undergoing regular physical training for more than 10 years with a training distance of at least 30 km per week. Subjects in group 3 had for the past three years taken part in the 'Grand Prix of Berne', a 16.5-km race run at a speed of 4.7 +/- 0.6 min km-1 (most recent race). Fat mass was more than 4 kg higher in old untrained men (P < 0.01, ANOVA) than in the other groups (young untrained men, 12.0 +/- 0.9 kg; old untrained men, 16.1 +/- 1.0 kg; old trained men, 11.0 +/- 0.8 kg), whereas body fat distribution (i.e. the ratio of upper to lower body fat mass) was similar between the three groups. The lean mass of old untrained men was more than 3.5 kg lower (P < 0.02, ANOVA) than in the other two groups (young untrained men, 56.4 +/- 1.0 kg; old untrained men, 52.4 +/- 1.0 kg; old trained men, 56.0 +/- 1.0 kg), mostly because of a loss of skeletal muscle mass in the arms and legs (young untrained men, 24.0 +/- 0.5 kg; old untrained men 20.8 +/- 0.5 kg; old trained men, 23.6 +/- 0.7 kg; P < 0.01, ANOVA). Resting metabolic rate per kilogram lean mass decreased with increasing age independently of physical activity (r = -0.42, P < 0.005). Fuel metabolism was determined by indirect calorimetry at rest. Protein oxidation was similar in the three groups. Old untrained men had higher (P < 0.001) carbohydrate oxidation (young untrained men, 13.2 +/- 1.0 kcal kg-1 lean mass; old untrained men, 15.2 +/- 1.3 kcal Kg-1; old trained men, 7.8 +/- 0.8 kcal kg-1), but lower (P < 0.05, ANOVA) fat oxidation (young untrained men, 10.1 +/- 1.2 kcal kg-1 lean mass; old untrained men, 6.5 +/- 1.0 kcal kg-1; old trained men, 13.7 +/- 1.0 kcal kg-1) than the other two groups. Mean plasma IGF-I level in old trained men was higher than in old untrained men (P < 0.05), but was still lower than that observed in young untrained men (P < 0.005) (young untrained men, 236 +/- 24 ng mL-1; old untrained men, 119 +/- 13 ng mL-1; old trained men, 166 +/- 14 ng mL-1). In summary, regular physical training in older men seems to prevent the changes in body composition and fuel metabolism normally associated with ageing. Whether regular physical training in formerly untrained old subjects would result in similar changes awaits further study.