597 research outputs found

    Natural organic matter in sedimentary basins and its relation to arsenic in anoxic ground water: the example of West Bengal and its worldwide implications

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    In order to investigate the mechanism of As release to anoxic ground water in alluvial aquifers, the authors sampled ground waters from 3 piezometer nests, 79 shallow (80 m) wells, in an area 750 m by 450 m, just north of Barasat, near Kolkata (Calcutta), in southern West Bengal. High concentrations of As (200-1180 mug L-1) are accompanied by high concentrations of Fe (3-13.7 mgL(-1)) and PO4 (1-6.5 mg L-1). Ground water that is rich in Mn (1-5.3 mg L-1) contains <50 mug L-1 of As. The composition of shallow ground water varies at the 100-m scale laterally and the metre-scale vertically, with vertical gradients in As concentration reaching 200 mug L-1 m(-1). The As is supplied by reductive dissolution of FeOOH and release of the sorbed As to solution. The process is driven by natural organic matter in peaty strata both within the aquifer sands and in the overlying confining unit. In well waters, thermotolerant coliforms, a proxy for faecal contamination, are not present in high numbers (<10 cfu/100 ml in 85% of wells) showing that faecally-derived organic matter does not enter the aquifer, does not drive reduction of FeOOH, and so does not release As to ground water.Arsenic concentrations are high (much greater than50 mug L-1) where reduction of FeOOH is complete and its entire load of sorbed As is released to solution, at which point the aquifer sediments become grey in colour as FeOOH vanishes. Where reduction is incomplete, the sediments are brown in colour and resorption of As to residual FeOOH keeps As concentrations below 10 mug L-1 in the presence of dissolved Fe. Sorbed As released by reduction of Mn oxides does not increase As in ground water because the As resorbs to FeOOH. High concentrations of As are common in alluvial aquifers of the Bengal Basin arise because Himalayan erosion supplies immature sediments, with low surface-loadings of FeOOH on mineral grains, to a depositional environment that is rich in organic mater so that complete reduction of FeOOH is common. (C) 2004 Published by Elsevier Ltd

    Evaluating Mood Changes in Response to Anthropogenic Noise with a Response-Slowing Task in Three Species of Zoo-housed Primates

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    In the zoo environment, anthropogenic noise is common as sound levels fluctuate due to visitors, construction, habitat design, and special events. In this study, changes in the mood of three species of zoo-housed primates in response to a loud annual event were evaluated with the response-slowing paradigm. In this paradigm, animals experiencing anxiety slow responses on simple cognitive tasks when emotional content is displayed. Following a previously validated approach, we measured latencies to touch potentially threatening (conspecific faces with directed gaze) and non-threatening (conspecific faces with averted gaze) images overlaid on a grey square, relative to neutral control images (grey squares only) on a touchscreen. In Experiment 1, four Japanese macaques (Macaca fuscata) were tested in two conditions: during a baseline (non-stressful) period and opportunistically during three days during which loud jets frequently flew overhead. Results indicated a significant effect of condition, with an increase in latency to touch images of conspecific faces relative to control images during the days of the loud event. In Experiment 2, chimpanzees (Pan troglodytes, n = 4) and western lowland gorillas (Gorilla gorilla gorilla, n = 2) were tested during the same loud event following a similar methodology. The results revealed subtle changes across conditions; however, this was likely driven by the apes increasing their response speed to face stimuli relative to control stimuli over time (habituation). These findings suggest that the macaques, but not the apes, underwent detectable affective changes during the loud event. With additional development, this relatively simple paradigm may be an effective and feasible way to evaluate real-time changes in the mood of zoo-housed animals

    Young people's conceptualizations of the nature of cyberbullying: A systematic review and synthesis of qualitative research

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    © 2020 Elsevier Ltd Introduction: Cyberbullying is a serious public health problem facing young people. Adults do not have first-hand experience of being immersed in social media in their youth and this necessitates the inclusion of youth voice in efforts to understand and address cyberbullying. This study aimed to synthesize qualitative studies which had explored young people's conceptualizations of the nature of cyberbullying, with a view to informing conceptual and intervention development. Methods: A systematic review and meta-ethnographic synthesis of qualitative studies was conducted. Nine databases were searched from inception to July 2018. The Critical Appraisal Skills Program assessment tool was used to appraise the quality of included studies. Results: Of 4872 unique records identified, 79 were reviewed in detail and 13 studies comprising 753 young people from 12 countries were included. Five key concepts were identified: Intent, Repetition, Accessibility, Anonymity and Barriers to Disclosure. A “line of argument” illustrating young people's conceptualization of cyberbullying was developed. Conclusion: The significance of information and communication technology in young people's lives, and the complexity of the cyber world in which they connect, must be recognized in conceptualizations of cyebrbullying. The distinctive features of cyberbullying identified in young people's characterization can be used to inform bottom-up research and intervention efforts.This research was funded by the Health Research Board through the SPHeRE Programme SPHeRE/2013/

    Behavioral responses to injury and death in wild Barbary macaques (Macaca sylvanus)

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    The wounding or death of a conspecific has been shown to elicit varied behavioral responses throughout thanatology. Recently, a number of reports have presented contentious evidence of epimeletic behavior towards the dying and dead among non-human animals, a behavioral trait previously considered uniquely human. Here, we report on the behavioral responses of Barbary macaques, a social, non-human primate, to the deaths of four group members (one high-ranking adult female, one high-ranking adult male, one juvenile male, and one female infant), all caused by road traffic accidents. Responses appeared to vary based on the nature of the death (protracted or instant) and the age class of the deceased. Responses included several behaviors with potential adaptive explanations or consequences. These included exploration, caretaking (guarding, carrying, and grooming), and proximity to wounded individuals or corpses, and immediate as well as longer-lasting distress behaviors from other group members following death, all of which have been reported in other non-human primate species. These observations add to a growing body of comparative evolutionary analysis of primate thanatology and help to highlight the multifaceted impacts of human-induced fatalities on an endangered and socially complex primate. © 2016, Japan Monkey Centre and Springer Japan

    Cooperation in wild Barbary macaques: factors affecting free partner choice

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    A key aspect of cooperation is partner choice: choosing the best available partner improves the chances of a successful cooperative interaction and decreases the likelihood of being exploited. However, in studies on cooperation subjects are rarely allowed to freely choose their partners. Group-living animals live in a complex social environment where they can choose among several social partners differing in, for example, sex, age, temperament, or dominance status. Our study investigated whether wild Barbary macaques succeed to cooperate using an experimental apparatus, and whether individual and social factors affect their choice of partners and the degree of cooperation. We used the string pulling task that requires two monkeys to manipulate simultaneously a rope in order to receive a food reward. The monkeys were free to interact with the apparatus or not and to choose their partner. The results showed that Barbary macaques are able to pair up with a partner to cooperate using the apparatus. High level of tolerance between monkeys was necessary for the initiation of successful cooperation, while strong social bond positively affected the maintenance of cooperative interactions. Dominance status, sex, age, and temperament of the subjects also affected their choice and performance. These factors thus need to be taken into account in cooperative experiment on animals. Tolerance between social partners is likely to be a prerequisite for the evolution of cooperation
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