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1.
The history of the way schizophrenia has been conceptualized in American psychiatry has led us to be hesitant to explore the role of social causation in schizophrenia. But there is now good evidence for social impact on the course, outcome, and even origin of schizophrenia, most notably in the better prognosis for schizophrenia in developing countries and in the higher rates of schizophrenia for dark-skinned immigrants to England and the Netherlands. This article proposes that “social defeat” may be one of the social factors that may impact illness experience and uses original ethnographic research to argue that social defeat is a common feature of the social context in which many people diagnosed with schizophrenia in America live today.  相似文献   

2.
Researchers consider group size in primates to be determined by complex relationships among numerous ecological forces. Antipredator benefits and better resource defense are the primary pressures for large groups. Conversely, intragroup limited food availability, can result in greater intragroup feeding competition and individual energy expenditure in larger groups, creating energetic advantages for individuals in small groups and placing an upper limit group size. However, the extent to which food availability constrains group size remains unclear for many species, including black howlers (Alouatta pigra), which ubiquitously live in small social groups (≤10 individuals). We studied the relationship between group size and 2 key indices of feeding competition—day journey length and activity budgets—in 3 groups of wild Alouatta pigra at a hurricane-damaged site in Belize, Central America. We controlled for differences in food availability between home ranges (food tree density) and compared both indicators of feeding competition directly with temporal variation in food availability for each group. Our results show no consistent association between resource availability, group size, and either index of competition, indicating that feeding competition does not limit group size at the site—i.e., that larger groups can form without increased costs of feeding competition. The results support the search for other explanations, possibly social ones, for small group size in the primates, and we conclude with suggestions and evidence for such alternative explanations.  相似文献   

3.
Over the past several decades, archeological research on the Northwest Coast of North America has focused on the evolution of the coast's well‐known native societies. This research has two broad goals: building local and regional culture histories spanning the Holocene and answering processual questions about the evolution and persistence of cultural complexity among hunter‐gatherers. Cultural complexity includes relatively dense populations, partial to full sedentism, corporate groups, some degree of occupational specialization, permanent social inequality, and control of property. 1 - 3 Recently archeologists have begun to investigate whether the coast was a possible route for the peopling of North America. Presently, the earliest known sites on the coast date to about 9,000 BC, although it is likely that the initial occupation was earlier. Some aspects of cultural complexity had developed on the coast by 2,500 BC, with permanent inequality present by 900 BC, if not earlier. Central to this development were large corporate households, intensive food production and storage, and technological innovations including water‐tight wooden containers and large‐capacity boats. Patterns of complexity on the coast continued to change through the arrival of Europeans in the mid‐1700s.  相似文献   

4.
Alaska Natives have one of the highest rates of food-borne botulism worldwide. All outbreaks have been associated with the consumption of native foods, but in recent years outbreaks have occurred in previously unaffected areas and have involved new food items. Five botulism outbreaks occurred between 1975 and 1985 in an area of southwestern Alaska without previous confirmed outbreaks and among one ethnic group, the Yupik Eskimo. Of the 5 outbreaks, 3 were associated with fermented beaver tail, a nontraditional native food recently introduced into the region. Preparation techniques vary widely within villages and among ethnic groups. Traditional fermentation techniques have changed over the past 50 years; current preparation methods used by some families and ethnic groups may be more favorable for Clostridium botulinum growth. Prevention efforts should be targeted at high-risk subgroups of Alaska Natives who appear to have modified traditional practices and increased their risk of food-borne botulism.  相似文献   

5.
The reported annual yield from inland capture fisheries in 2008 was over 10 million tonnes, although real catches are probably considerably higher than this. Inland fisheries are extremely complex, and in many cases poorly understood. The numerous water bodies and small rivers are inhabited by a wide range of species and several types of fisher community with diversified livelihood strategies for whom inland fisheries are extremely important. Many drivers affect the fisheries, including internal fisheries management practices. There are also many drivers from outside the fishery that influence the state and functioning of the environment as well as the social and economic framework within which the fishery is pursued. The drivers affecting the various types of inland water, rivers, lakes, reservoirs and wetlands may differ, particularly with regard to ecosystem function. Many of these depend on land-use practices and demand for water which conflict with the sustainability of the fishery. Climate change is also exacerbating many of these factors. The future of inland fisheries varies between continents. In Asia and Africa the resources are very intensely exploited and there is probably little room for expansion; it is here that resources are most at risk. Inland fisheries are less heavily exploited in South and Central America, and in the North and South temperate zones inland fisheries are mostly oriented to recreation rather than food production.  相似文献   

6.
What cues support social influences on food preference in tufted capuchins? Although vision is important for food discrimination, we hypothesized that olfactory cues might also be involved. In Experiment 1, we assessed whether semolina flavored with a novel odor and eaten by a demonstrator, elicits more interest than semolina flavored with a familiar odor and eaten by a demonstrator, and to what extent the observer's interest towards the demonstrator was elicited by the food itself or by the odor impregnating the demonstrator's oral area. In Experiment 2, we investigated whether having encountered a novel odor in a social context increases the observer's subsequent consumption of semolina carrying this odor versus semolina carrying another novel odor previously encountered in a non-social context. We tested 15 demonstrator-observer pairs. Eight observers were offspring of the demonstrator; 7 observers were not offspring of the demonstrator. Offspring (but not non-offspring) expressed interest towards the demonstrator's food significantly more when the odor was novel than when it was familiar. Offspring (but not non-offspring) were more interested when the demonstrator's food was present than when only its odor was available. Finally, having encountered the novel odor in the social context did not lead to greater consumption. Our findings demonstrate that in closely bonded pairs, foods carrying novel odors elicit interest, though it is prompted mainly by the food itself. In contrast with other macrosmatic mammalian species, capuchin consumption of a food whose odor was previously encountered in a social context was not greater than that of a food whose odor was previously encountered when alone.  相似文献   

7.
The feedbacks from population density to demographic parameters, which drive population regulation, are the accumulated results of several ecological processes. The compensatory feedback from increased population density to fertility includes at least two distinct factors, the effects of decreases in per capita food level and increases in the social density (the number of interacting individuals). Because these effects have been studied separately, their relative importance is unknown. It is also unclear whether food limitation and social density combine additively to influence fertility. We investigated these questions with two factorial experiments on reproduction in the Least Killifish, Heterandria formosa. In one experiment, we crossed two levels of density with two levels of a total food ration that was distributed to all individuals. In the other experiment, we crossed two levels of density with two levels of per capita food. Whereas the first experiment suggested that the effects of variation in food level and density were synergistic, the second experiment indicated that they were not. The apparent synergism—the statistical interaction of food and density levels—was the result of confounding per capita food with social density in that design. In the second experiment, the effects of social density on reproductive rate were stronger than the effects of food level, whereas the effects of food level were stronger on offspring size at parturition than those of social density. The results suggest that the social stresses that emerge at higher densities play an important role in the compensatory response of fertility to density, a role, that is, at least as important as that of decreased per capita food levels.  相似文献   

8.
In social groups, individuals' dominance rank, social bonds, and kinship with other group members have been shown to influence their foraging behavior. However, there is growing evidence that the particular effects of these social traits may also depend on local environmental conditions. We investigated this by comparing the foraging behavior of wild chacma baboons, Papio ursinus, under natural conditions and in a field experiment where food was spatially clumped. Data were collected from 55 animals across two troops over a 5‐month period, including over 900 agonistic foraging interactions and over 600 food patch visits in each condition. In both conditions, low‐ranked individuals received more agonism, but this only translated into reduced foraging performances for low‐ranked individuals in the high‐competition experimental conditions. Our results suggest one possible reason for this pattern may be low‐ranked individuals strategically investing social effort to negotiate foraging tolerance, but the rank‐offsetting effect of this investment being overwhelmed in the higher‐competition experimental environment. Our results also suggest that individuals may use imbalances in their social bonds to negotiate tolerance from others under a wider range of environmental conditions, but utilize the overall strength of their social bonds in more extreme environments where feeding competition is more intense. These findings highlight that behavioral tactics such as the strategic investment of social effort may allow foragers to mitigate the costs of low rank, but that the effectiveness of these tactics is likely to be limited in certain environments.  相似文献   

9.
The goal of this research work was to assist consumers in considering environmental aspects of food consumption. A simplified, modular LCA approach has been used to evaluate the impacts from the consumers’ point of view. Comparative LCA’s have been calculated for five single aspects of decisions: type of agricultural practice, origin, packaging material, type of preservation, and consumption. The inventory for one module includes the environmental impacts related to one particular product characteristic. The modular LCA allows one to investigate the trade-offs among different decision parameters. It could be shown that most of the decision parameters might have an influence on the overall impact of a vegetable product. Greenhouse production and vegetables transported by air cause the highest surplus environmental impact. For meat products, the agricultural production determines the overall environmental impact. The total impact for vegetable or meat purchases may vary by a factor of eight or two-and-a-half. Different suggestions for consumers have been ranked according to the variation of average impacts, due to a marginal change of behaviour. Avoiding air-transported food products leads to the highest decrease of environmental impacts.  相似文献   

10.
Earlier weaning has often been suggested as a cause for population growth after the evolution of food production. However, evidence for weaning-time reduction is largely circumstantial. Collagen stable nitrogen- and carbon-isotope ratios from juvenile and adult burials from four sites in eastern North America were measured to estimate weaning onsets and durations before and after the appearance of intensive food production. Two preagricultural Late Archaic sites (Indian Knoll and Carlston Annis) are compared with two highly agricultural Middle Mississippian sites (Angel and Tinsley Hill). Isotopic data and paleodemographic measures of birth rates provide no evidence for changes in weaning behavior or fertility with the development of food production in the prehistoric Lower Ohio Valley. Birth rates and weaning behavior appear to have been roughly the same at all four sites. These results indicate that models attributing population growth after the appearance of food production to earlier weaning are not universally applicable.  相似文献   

11.
In early spring, food and water consumption and the excretion and clearances of urine and solutes reached maximal rates. Water consumption exceeded food intake and urine production and plasma osmolality was lowest. Toward early and late summer, water intake decreased faster than food consumption and urine production. Urea excretion and clearances diminished with food consumption, while creatinine clearance decreased only slightly. Plasma osmolality increased. The data are consistent with rehydration soon after hibernation is completed, followed by a period of weight gain and dehydration in preparation for the next prolonged period of hibernation.  相似文献   

12.
Visalberghi and Fragaszy [Animal Behaviour 49:1089–1095, 1995] have shown that social influences affect acceptance of novel foods. However, little is known about the temporal course on which such influences act (e.g., for how long they persist and for how many encounters they are effective). To explore this issue, 11 adult tufted capuchins were observed during ten successive encounters with eight unfamiliar foods (phase 1, in which subjects were tested in social or individual condition) and ten more encounters 6 months later (phase 2, in which all subjects were tested in social condition). A total of 680 observational sessions were carried out. Results show that during the first five encounters in phase 1, capuchins ate more when they encountered these foods in the presence of their groupmates than if they encountered them alone. Thereafter, during the second five encounters of phase 1, foods were consumed equivalently whether presented to monkeys socially or individually. In phase 2, the foods were consumed equivalently regardless of the previous circumstance of their presentation (social or alone). In phase 2, consumption was similar to that scored in a previous study for familiar foods [Visalberghi & Fragaszy, Animal Behaviour 49:1089–1095, 1995]. We conclude that 1) foods remain unfamiliar to capuchins only for the first few encounters, 2) social facilitation of consumption of unfamiliar foods is of limited duration, and 3) individuals consumed equivalent amounts of an unfamiliar food when they repeatedly encountered it alone or in the presence of groupmates. These results caution those who interpret similar feeding habits in primate groups as evidence of social influences. Am. J. Primatol. 45:367–380, 1998. © 1998 Wiley-Liss, Inc.  相似文献   

13.
Wild foods contribute towards the food security of an estimated one billion people. In light of expectations of the contribution of wild foods to sustainable and climate-resilient livelihoods and widespread evidence of their consumption, their contribution to households’ diets requires a more nuanced understanding, specifically with respect to their safety net function during food shortages. Data were collected from two villages in Venda, South Africa, selected due to differences in mean annual precipitation. Semi-structured interviews were administered to 170 households and a Participatory Rural Appraisal was conducted to assess the influence of multiple variables, including household characteristics and site, on wild food use. Household archetypes were defined based on the frequency of consumption in response to increasing food scarcity. Our findings suggest limitations to the safety net function of wild foods including seasonal fluctuations in availability and decreased availability during extreme events, with dependent households decreasing their consumption frequency in response to food scarcity. Given this potential poverty trap, further research is required, particularly in terms of when the safety net function of wild foods may be weak or detrimental to the livelihoods of the vulnerable.  相似文献   

14.
Social insects have an efficient recognition system that guarantees social cohesion and protection against intruders in their colonies and territories. However, the energy costs in constant conflicts with neighboring colonies could promote a reduction in the fitness of colonies. Here, we evaluated the effect of previous exposure to allocolonial odor and the consumption of similar food resources on aggressive behavior and choice of allocolonial cues in Nasutitermes aff. coxipoensis (Termitidae: Nasutitermitinae). Our results showed that intercolonial aggressiveness was not affected by previous exposure to allocolonial odor and by the consumption of similar food resources. However, individuals previously exposed to allocolonial odor were more attracted to these odors than individuals who had no prior exposure to allocolonial odor. In addition, individuals from colonies of N. aff. coxipoensis that use similar food resources increased alertness via a greater number of vibration than individuals who consumed different food resources. In general, our results indicate that colonies of N. aff coxipoensis perceive allocolonial cues that have been previously exposed and that the consumption of similar resources triggers an alert signal between individuals. Additional studies are necessary to assess how widespread this capacity of perception is present among the different Isoptera groups and the consequences of colony recognition odor cues on termite space use.  相似文献   

15.
Over the past decade, there has been enormous interest in understanding the great diversity of microbial cooperative behaviors, including communication, group‐based swarming, fruiting‐body formation, and the secretion of group‐beneficial enzymes and food‐scavenging molecules. Zhang and Rainey, henceforth Z&R, recently contended that sociomicrobiologists have been overzealous in their casting of microbes as inherently social organisms, and too hasty in interpreting microbial behaviors in a social evolutionary framework. This challenge accompanied a set of experiments in which they revisited one of the best‐studied social behaviors in bacteria—the production of diffusible, sharable iron‐scavenging siderophore molecules. Z&R posit that their findings challenge the view that siderophore production is a cooperative trait. Here, we demonstrate that their arguments are flawed, and stem from both technical mistakes and misunderstandings of social evolution theory.  相似文献   

16.
The growing human population and the increase in per capita food consumption are driving agriculture expansion and affecting natural ecosystems around the world. To balance increasing agriculture production and nature conservation, we must assess the efficiency of land‐use strategies. Soybean production, mainly exported to China and Europe, has become the major driver of deforestation in dry forest/savanna ecosystems of South America. In this article we compared land cover patterns (based on satellite imagery) and land‐use and human population trends (based on government statistics) in regions with two contrasting development pathways in the Chaco dry forests of northern Argentina, since the early 1970s. The area (ca. 13 million hectares) includes one of the largest continuous patches of tropical dry forests and has experienced rapid land‐use change. In the region where land use has been driven by government‐sponsored colonization programs, the expansion of extensive grazing has led to a growing rural population, low food production, and widespread environmental degradation. In contrast, in the region dominated by market‐driven soybean expansion, the rural population has decreased, food production is between 300% and 800% greater, and low‐density extensive cattle production has declined over extensive remaining forested areas, resulting in a land‐use trend that appears to better balance food production and nature conservation.  相似文献   

17.
Bingham and Souza 1 have presented an evolutionary theory that specifies a causal relationship between the advent of powerful projectile weapons such as the bow and radical rearrangements in social relations and histories. They propose that the acquisition of weapons that permitted humans to kill at ever‐increasing distances provided the coercive means to suppress conflicts of interest among nonkin, self‐interested individuals in social groups, thus paving the way for greater social complexity. An unprecedented reduction in projectile point size identifies the arrival of the bow ca. A.D. 300 in the Eastern Woodlands of North America, which initiated a causal chain of cultural changes. In the Midwest, the bow, combined with food production, precipitated the decline of Hopewell by conferring household autonomy and dispersal, which at first suppressed social complexity, but later created conditions favorable to maize intensification. In the lower Southeast, where food production was unimportant, populations aggregated at concentrated wild‐food sources, and the bow did not confer household autonomy. The relationship between the bow and social complexity varied under different environmental, social, and historical conditions.  相似文献   

18.
In this article, I explore the contradictions that four new teachers experienced as their commitments to social justice collide with urban school culture. Framed within Jean Lave and Etienne Wenger's (1999) theory of situated learning and development concepts of identity, practice, and relationships illustrate how teachers' ideals are challenged as socializing features of two communities of practice—the universities and schools—intersect in new teachers' development. This research contributes empirical evidence of the application of critical multicultural teacher preparation into practice, a cultural representation of how educational inequities are reproduced or disrupted in the situated contexts of urban schools, an application of Lave and Wenger's theory of Legitimate Peripheral Participation that incorporates formal and informal education across multiple activity settings, and a call for collaborative communities of practice that support teachers' situated learning in creating transformative practices.  相似文献   

19.
The carbon and nitrogen stable isotopic composition of the scalp hair and diet of Gidra-speaking people in four villages in Papua New Guinea is presented. The isotopic composition of hair was measured, while that of the diet was estimated from food consumption survey data and the measured isotopic composition and protein and carbohydrate contents of food items. The average isotopic ratios of the hair samples and of the diet varied among the four study villages, which were selected because of their diverse ecological settings. Comparison was made between hair and calculated dietary isotopic compositions. Two of the four diet-hair enrichment values obtained for 13C (+1.8 and 2.2%‰) were similar to those previously reported (1.4–2.0%‰), but the other two values (3.7 and 4.8%) were greater than in earlier reports. 15N enrichment was systematically greater (by 1%‰) than reported values (∼4.3%‰) except for one village, where a much greater enrichment (6.9%‰) was found. The factors potentially relevant to these deviations are discussed. Possible errors in estimating the dietary isotopic composition and minor modifications of dietary habits revealed by food consumption surveys could explain most of the discrepancies. However, the great enrichment of 15N found in one of the villages remains unexplained. © 1996 Wiley-Liss, Inc.  相似文献   

20.
The aim of this study was to evaluate the feeding activity and the rhythm of daily locomotor activity of the convict cichlid (Amatitlania sp.) kept in different social groups under a self-feeding system. A total of 120 animals was distributed among six repetitions of four social groups, as follows: group 1 with one male and one female per tank; group 2 with three males and three females per tank; group 3 with six males per tank; and group 4 with six females per tank. Feeding activity (FA) and locomotor activity (LA) were evaluated using photoelectric presence-sensors connected to automatic feeders. The fish were fed a commercial extruded diet (46% crude protein and 3600 kcal kg−1 of digestible energy). Animal growth was evaluated for all groups. After 30 days of experimentation, the fish stabilized their demands by adjusting their consumption. Amatitlania sp. showed predominantly diurnal FA and LA. All groups showed a peak of activity when the light was turned on and when it was turned off. In summary, FA and LA of Amatitlania sp. are predominantly diurnal and independent of social group. Pairs and groups of males and females together consume less food in relation to groups of one sex or the other due to reproductive behaviour. On the other hand, groups of only males or females consume more food because they lack reproductive stimuli and thus prioritize growth. These results may support good feeding management practices for this ornamental cichlid. Studies relating feeding behaviour with different social groups are of great importance for determining effective feeding strategies for this species in captivity. Thus, such a study assists in a more efficient production of Amatitlania sp.  相似文献   

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