2,319 research outputs found

    Reactions to infant death by wild vervet monkeys (Chlorocebus pygerythrus) in KwaZulu-Natal, South Africa: prolonged carrying, non-mother carrying, and partial maternal cannibalism.

    Get PDF
    Observations of dead infant carrying have been reported for many primate species, and researchers have proposed several hypotheses to explain this behaviour. However, despite being a relatively well-studied species, reports of dead infant carrying in wild vervet monkeys (Chlorocebus pygerythrus) remain scarce. Here we report 14 observations of dead infant carrying by female vervet monkeys in a population at Mawana Game Reserve, KwaZulu-Natal, South Africa. Most of the females carried the dead infant for a day or less, but one female carried her infant for at least 14 days. In one case the maternal sister of a dead infant carried it after the death of their mother. We also report a case of mother-infant cannibalism: a female consumed part of her deceased infant's tail. Other post-mortem care-taking behaviours such as grooming, smelling and licking were also recorded. Of 97 recorded infant deaths in this study population since 2010, 14.4% are known to have elicited dead infant carrying, a proportion similar to that reported for other monkey species. We discuss our observations in relation to various hypotheses about this behaviour, including the post-parturition hormones hypothesis, learning to mother hypothesis, and unawareness of death hypothesis

    Field experiments with wild primates reveal no consistent dominance-based bias in social learning

    Get PDF
    Directed social learning suggests that information flows through social groups in a nonrandom way, with individuals biased to obtain information from certain conspecifics. A bias to copy the behaviour of more dominant individuals has been demonstrated in captive chimpanzees, Pan troglodytes, but has yet to be studied in any wild animal population. To test for this bias using a field experiment, one dominant and one low-ranking female in each of three groups of wild vervet monkeys, Chlorocebus aethiops pygerythrus, was trained on alternative methods of opening an 'artificial fruit'. Following 100 demonstrations from each model, fruits that could be opened either way were presented to each group and all openings were recorded. Overall, the dominant females were not attended to more than low-ranking females during the demonstrations, nor were their methods preferentially used in the test phase. We conclude that these monkeys show no overall bias to copy high-ranking models that would lead to a high-ranking model's behaviour becoming more prevalent in the group than a behaviour demonstrated by a low-ranking model. However, by contrast, there were significant effects of observer monkeys' rank and sex upon the likelihood they would match the dominant model. Additionally we found that the dominant models were more likely to stick to their initially learned method than were low-ranking model

    Social attention biases in juvenile wild vervet monkeys: implications for socialisation and social learning processes.

    Get PDF
    The concept of directed social learning predicts that social learning opportunities for an individual will depend on social dynamics, context and demonstrator identity. However, few empirical studies have examined social attention biases in animal groups. Sex-based and kinship-based biases in social learning and social attention towards females have been shown in a despotic and female philopatric primate: the vervet monkey (Chlorocebus pygerythrus). The present study examined social attention during the juvenile period. Social attention was recorded through 5-min focal observations during periods of natural foraging. Kin emerged as the most important focus of social attention in juveniles, intensified by biased spatial proximity towards matrilineal related members. The highest-ranking conspecifics were more frequently observed by juveniles than low-ranking ones. Additionally, younger and orphaned juveniles showed higher levels of social attention overall, compared to other age categories. No effect of the juvenile's hierarchical rank was detected, suggesting that the variation in social attention recorded reflects different biases and stages of social learning and socialisation, rather than social anxiety. Juvenile females tended to exhibit a dominance-based bias more strongly than did males. This might be explained by a greater emphasis on attaining social knowledge during juvenile socialisation in the philopatric sex. Moreover, despite a preferred association between juveniles, social attention was more often directed to adults, suggesting that adults may still be more often chosen as a target of attention independent of their dominance rank

    Early responses to chemotherapy detected by pulse cytophotometry.

    Get PDF
    DNA/cell distributions were recorded by automated cytofluorometry (=pulse cytophotometry) in bone-marrow aspirates of leukaemia and lymphosarcoma patients subjected to chemotherapy. In most cases, early perturbations in DNA/cell histographs were observed, characteristically reflecting the known mode of action of the drugs. These changes in general preceded the clinical observation of drug response. In a series of 23 measurements in 19 patients, a positive correlation between early cytophotometric changes and clinical effects of chemotherapy was observed in 17 patients. Five patients were negative for both cytophotometric and clinical reactions and one patient was probably false-positive. The validity of the assay for early detection of drug resistance in acute leukaemia and related diseases is discussed

    Научно-технический прогресс или безопасность человечества

    Get PDF
    Постепенное развитие общественного производства, его постоянное совершенствование являются фундаментальными закономерностями экономической жизни человечества. Они основываются на прогрессе науки и техники. Научно-технический прогресс за тысячелетия человеческой цивилизации прошел сложный и противоречивый путь развития. Это было вызвано тем, что именно технический прогресс, который осуществлялся на первых этапах развития общества, осуществлялся отдельно от научного прогресса до конца XVIII - начала XIX в. И только в период промышленной революции началось быстрое сближение научного и технического прогресса и возник целостный научно-технический прогресс.Gradual development of social production, its constant improvement of the fundamental laws of the economic life of mankind. They are based on the progress of science and technology. Scientific and technological progress for the millennium of human civilization has passed a complex and contradictory path of development. This was due to the fact that it was the technical progress that was carried out at the first stages of the development of society that was carried out separately from scientific progress until the end of the eighteenth and early nineteenth centuries. And only in the period of the industrial revolution did the rapid rapprochement of scientific and technological progress and the emergence of integral scientific and technological progress began

    Additive technology of obtaining products from ceramics

    Get PDF
    Created an original design of the device, which lets you create samples of thermoplastic ceramic slurry, which after sintering, are obtained ceramics with high strength and hardness parameters

    Research Chimpanzees May Get a Break

    Get PDF
    A recent report by the Institute of Medicine leaves few urgent reasons standing for the continued use of chimpanzees in biomedical research. It is high time to think about their retirement, Frans de Waal argues, without neglecting prospects for non-invasive research on behavior, cognition, and genetics

    Resection arthroplasty for luxation of the manubrio-sternal joint in rheumatoid arthritis—a case report

    Get PDF
    Contains fulltext : 89408.pdf (publisher's version ) (Open Access)1 juni 201

    Primates are living links to our past: The contribution of comparative studies with wild vervet monkeys to the field of social cognition.

    Get PDF
    By studying the behavior of nonhuman primates, particularly in wild settings, researchers have been able to investigate a range of cognitive abilities, shedding light on the evolution of certain aspects of cognition and revealing potential evolutionary precursors of many capacities considered uniquely human. Vervet monkeys (Chlorocebus pygerythrus) have been widely investigated due to their prevalence and their suitability for experimental testing in the wild with an ecologically valid approach that is not possible with many other primates, especially apes. Here we review advances in the understanding of a number of cognitive and behavioral processes that have been gleaned from studies conducted with wild vervet monkeys over the past half century, primarily focusing on social cognitive abilities. We direct our attention to three major areas of study; communication, cooperation and trade, and social learning. We discuss how findings from this species have contributed (and continue to contribute) to our understanding of the evolution of human cognitive capacities and suggest future avenues of research with this species

    Post-Conflict Affiliation by Chimpanzees with Aggressors: Other-Oriented versus Selfish Political Strategy

    Get PDF
    Consolation, i.e., post-conflict affiliation directed from bystanders to recent victims of aggression, has recently acquired an important role in the debate about empathy in great apes. Although similar contacts have been also described for aggressors, i.e., appeasement, they have received far less attention and their function and underlying mechanisms remain largely unknown. An exceptionally large database of spontaneous conflict and post-conflict interactions in two outdoor-housed groups of chimpanzees lends support to the notion that affiliation toward aggressors reduces the latter's aggressive tendencies in that further aggression was less frequent after the occurrence of the affiliation. However, bystander affiliation toward aggressors occurred disproportionally between individuals that were socially close (i.e., affiliation partners) which suggest that it did not function to protect the actor itself against redirected aggression. Contrary to consolation behavior, it was provided most often by adult males and directed toward high ranking males, whereas females engaged less often in this behavior both as actors and recipients, suggesting that affiliation with aggressors is unlikely to be a reaction to the distress of others. We propose that bystander affiliation toward aggressors may function to strengthen bonds between valuable partners, probably as part of political strategies. Our findings also suggest that this post-conflict behavior may act as an alternative to reconciliation, i.e., post-conflict affiliation between opponents, in that it is more common when opponents fail to reconcile
    corecore