Loud, sad or bad: young people's perceptions of peer groups and smoking. (1/455)

This paper suggests that most 13 year olds and many 11 year olds have a clear and detailed grasp of their own social map, recognize the pecking order which is established amongst their peers and are aware of the different levels of risk-taking behaviour, including smoking, adopted by different peer groups in their school year. Thirty six 11 year olds and 40 13 year olds took part in the study. Their remarkably consistent views about which pupils adopt or reject smoking are closely related to their perceptions of their social map. Their accounts differentiate top girls, top boys, middle pupils, low-status pupils, trouble-makers and loners, associating smoking behaviour consistently with three of the five groups--the top girls, the low-status pupils and the trouble makers. Top boys, although sharing many of the characteristics of top girls, have an added protection factor--their keen interest in football and physical fitness. From their descriptions, it is apparent that different groups of pupils smoke for different reasons which are related to pecking order and group membership. The implications of these young people's views for health education programmes to prevent smoking and other risk-taking behaviours are far reaching.  (+info)

Coalition formation in animals and the nature of winner and loser effects. (2/455)

Coalition formation has been documented in a diverse array of taxa, yet there has been little formal analysis of polyadic interactions such as coalitions. Here, we develop an optimality model which examines the role of winner and loser effects in shaping coalition formation. We demonstrate that the predicted patterns of alliances are strongly dependent on the way in which winner and loser effects change with contestant strength. When winner and loser effects decrease with the resource-holding power (RHP) of the combatants, coalitions will be favoured between the strongest members of a group, but not between the weakest. If, in contrast, winner and loser effects increase with RHP, exactly the opposite predictions emerge. All other things being equal, intervention is more likely to prove worthwhile when the beneficiary of the aid is weaker (and its opponent is stronger), because the beneficiary is then less likely to win without help. Consequently, intervention is more probable when the impact of victory on the subsequent performance of a combatant increases with that individual's strength because this selects for intervention in favour of weaker combatants. The published literature on hierarchy formation does not reveal how winner and loser effects actually change with contestant strength and we therefore hope that our model will spur others to collect such data; in this light we suggest an experiment which will help to elucidate the nature of winner and loser effects and their impact on coalition formation in animals.  (+info)

Social effects and boar taint: significance for production of slaughter boars (Sus scrofa). (3/455)

A study was conducted to elucidate the effects of social factors on the concentrations of boar taint substances, androstenone and skatole, in boars. The factors included dominance (social rank) and the effects of strongly tainted animals on other members of the group. Four successive replicates of 100 pigs (50 boars + 50 gilts) with an average live weight of 24 kg were randomly allocated to 10 pens of 10. Data for this study were collected during the period of 67 to 114 kg of live weight and included the repetitive recording of agonistic behavior during competitive feeding; blood sampling for determination of plasma androstenone, skatole and testosterone in boars; feces sampling for determination of skatole content; and collection of bulbourethral glands in boars, and uteri plus ovaries in gilts at slaughter, for the assessment of sexual maturity. Results show an influence of social rank on plasma concentrations of androstenone (P = .0001) and testosterone (P = .0001), the weight of the bulbourethral glands (P = .0001), and plasma skatole (P = .02). Pens were classified according to the pig with the highest concentration of androstenone in the pen into high, medium, and low maximum pens. In pens with high maximum concentrations of androstenone, the second-highest androstenone concentration (P = .0001), and the average concentration (P = .0003) in the pen were higher than those in pens with medium or low maximum concentrations of androstenone. Mean aggression level was also higher (P = .02), but pens with high maximum aggression level did not have higher mean androstenone concentration. Rank effect on androstenone was more important than aggression effect. Neither maximum androstenone concentration nor maximum aggression level in a pen was related to the pen mean stage of sexual maturity in either sex. No influences of rank, aggression, or aggression received were found on the feces skatole level, and no pheromonal communicative function was demonstrated for skatole. High androstenone concentrations did not have a suppressive effect on androstenone concentrations in other males of the group; on the contrary, the levels were increased. This may be due to a stimulating effect of androstenone and, possibly, mating activity. Consequently, in the production of boars for slaughter, strongly tainted animals should be avoided or removed and mating activity minimized. This could be facilitated by, for instance, slaughtering before sexual maturity or separate rearing of the sexes.  (+info)

Skin darkening, a potential social signal in subordinate arctic charr (Salvelinus alpinus): the regulatory role of brain monoamines and pro-opiomelanocortin-derived peptides. (4/455)

Arctic charr were allowed to interact in groups of three for 5 days. Skin darkness was quantified by measuring the mean brightness of individual fish before and after social interaction. Brain levels of monoamines and monoamine metabolites and plasma concentrations of cortisol, adrenocorticotropic hormone (ACTH), N-acetyl-(beta)-endorphin and alpha-melanocyte-stimulating hormone (alpha-MSH) were analysed. The results show that social subordination resulted in a significant skin darkening. Furthermore, plasma concentrations of alpha-MSH, ACTH and cortisol were elevated in subordinates, and these fish also displayed elevated levels of 5-hydroxyindoleacetic acid (5-HIAA) in the telencephalon. The ratio of [5-HIAA] to serotonin [5-HT] was increased in several brain areas. In addition, the ratio of 3-methoxy-4-hydroxyphenylglycol (MHPG) to norepinephrine (NE) concentrations was significantly increased in the optic tectum of subordinate fish. Skin darkness following social interaction showed a significant positive correlation with plasma levels of alpha-MSH. Plasma levels of ACTH and alpha-MSH were both positively correlated with that of cortisol. Brain [5-HIAA]/[5-HT] ratios were positively correlated with circulating plasma levels of ACTH, and a similar positive correlation was seen between [MHPG]/[NE] ratios in the optic tectum and plasma levels of ACTH, alpha-MSH and N-acetyl-beta-endorphin. In contrast, hypothalamic [MHPG]/[NE] ratios displayed a negative correlation with plasma alpha-MSH concentrations. The present study demonstrates that social stress induces skin darkening in Arctic charr and that this effect could be mediated by a stress-induced increase in the levels of alpha-MSH in the circulation. Furthermore, the results suggest that 5-HT and NE in the central nervous system could be factors regulating the pituitary release of ACTH and alpha-MSH.  (+info)

Oral administration of a corticotropin-releasing hormone receptor antagonist significantly attenuates behavioral, neuroendocrine, and autonomic responses to stress in primates. (5/455)

We evaluated the effects of the lipophilic nonpeptide corticotropin-releasing hormone (CRH) type 1 receptor antagonist antalarmin on the behavioral, neuroendocrine, and autonomic components of the stress response in adult male rhesus macaques. After oral administration, significant antalarmin concentrations were detected in the systemic circulation and the cerebrospinal fluid by a mass spectrometry-gas chromatography assay developed specifically for this purpose. Pharmacokinetic and dose-response studies suggested that an oral dose of 20 mg/kg was optimal for behavioral and endocrine effects. We then administered this dose in a double-blind, placebo-controlled fashion to monkeys exposed to an intense social stressor: namely, placement of two unfamiliar males in adjacent cages separated only by a transparent Plexiglas screen. Antalarmin significantly inhibited a repertoire of behaviors associated with anxiety and fear such as body tremors, grimacing, teeth gnashing, urination, and defecation. In contrast, antalarmin increased exploratory and sexual behaviors that are normally suppressed during stress. Moreover, antalarmin significantly diminished the increases in cerebrospinal fluid CRH as well as the pituitary-adrenal, sympathetic, and adrenal medullary responses to stress. We conclude that CRH plays a broad role in the physiological responses to psychological stress in primates and that a CRH type 1 receptor antagonist may be of therapeutic value in human psychiatric, reproductive, and cardiovascular disorders associated with CRH system hyperactivity.  (+info)

Income, occupational position, qualification and health inequalities--competing risks? (comparing indicators of social status). (6/455)

STUDY OBJECTIVE: The debate on health inequalities has shifted from the consequences of occupational position, as expressed in the Registrar General's classification, to consequences of material living conditions. This change in interest occurred without comparative analyses of different sources of health inequalities. Thus this study investigated the relative contribution of "material resources" (income), "qualification" and "occupational position" for explaining social differentials in mortality. DESIGN AND SETTING: Analyses were performed with records from a statutory health insurance in West Germany. The analyses were performed with data of 84,814 employed men and women between 25 and 65 years of age who were insured between 1987 and 1995 for at least 150 days. RESULTS: The three indicators were statistically associated, but not strong enough to warrant the conclusion that they share the same empirical content. The relative risk (hazard rate) for income by controlling for occupational position and gender for the highest as compared with the lowest category was 1.99 (95% CI 1.66, 2.39). The corresponding relative risk for income by controlling for qualification and gender was 2.03 (95% CI 1.68, 2.46). In both multivariate analyses, the effects of occupational position and qualification were no longer interpretable because of large confidence intervals. In sum, income related relative mortality risks were the comparably highest, while qualification and occupational position were no longer substantial. CONCLUSIONS: The results emphasise the present discussion on the consequences of material living conditions. Income on the one hand and qualification and occupational position on the other are largely independent. Mortality related effects of income override those of the other socioeconomic status indicators. However, seen in a time perspective, qualification may still have a placement function at least for the first occupational position.  (+info)

Social status controls somatostatin neuron size and growth. (7/455)

Many animal species show flexible behavioral responses to environmental and social changes. Such responses typically require changes in the neural substrate responsible for particular behavioral states. We have shown previously in the African cichlid fish, Haplochromis burtoni, that changes in social status, including events such as losing or winning a territorial encounter, result in changes in somatic growth rate. Here we demonstrate for the first time that changes in social status cause changes in the size of neurons involved in the control of growth. Specifically, somatostatin-containing neurons in the hypothalamus of H. burtoni increase up to threefold in volume in dominant and socially descending animals compared with cell sizes in subordinate and socially ascending fish. Because somatostatin is known to be an inhibitor of growth hormone release, the differences in cell size suggest a possible mechanism to account for the more rapid growth rates of subordinate and socially ascending animals compared with those of dominant or socially descending fish. These results reveal possible mechanisms responsible for socially induced physiological plasticity that allow animals to shift resources from reproduction to growth or vice versa depending on the social context.  (+info)

The mechanistic basis of aerobic performance variation in red junglefowl. (8/455)

We examined aerobic performance, organ and muscle mass and enzymatic activity in red junglefowl (Gallus gallus). We tested three models of performance limitation (central limits, peripheral limits, symmorphosis) and explored relationships between basal metabolic rate (BMR), aerobic capacity ( V (O2max)) and social rank. Males had a lower BMR, a higher V (O2max) and a greater aerobic scope than females. Females possessed larger peritoneal and reproductive organs, while males had larger hearts, lungs and leg muscles. In females, BMR was correlated with spleen mass and V (O2max) was correlated with hematocrit and large intestine mass. Male BMR was correlated with intestinal tract and lung mass, and V (O2max) was correlated with heart and pectoralis mass. Male citrate synthase activity averaged 57 % higher than that of females and was correlated with V (O2max) (this correlation was not significant in females). Female social status was not correlated with any variable, but male dominance was associated with higher aerobic scope, larger heart and lungs, smaller peritoneal organs and greater leg citrate synthase activity. We conclude that aerobic capacity is controlled by system-wide limitations (symmorphosis) in males, while in females it is controlled by central organs. In neither sex is elevated aerobic capacity associated with increased maintenance costs.  (+info)