42 research outputs found

    Positive and negative interactions with humans concurrently affect vervet monkey, Chlorocebus pygerythrus, ranging behavior

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    Many non-human primates adjust their behavior and thrive in human-altered habitats, including towns and cities. Studying anthropogenic influences from an animal’s perspective can increase our understanding of their behavioral flexibility, presenting important information for human-wildlife cohabitation management plans. Currently, research on anthropogenically disturbed wildlife considers either positive or negative aspects of human-wildlife encounters independently, highlighting a need to consider potential interactions between both aspects. Vervet monkeys, Chlorocebus pygerythrus, are a suitable species to address this gap in research as they tolerate urbanization, however, they are understudied in urban landscapes. We conducted this in KwaZulu-Natal, South Africa, where vervet monkeys are commonly found throughout the anthropogenic landscape. Here we determined, from a monkey’s perspective, how the frequency and nature of human-monkey interactions, both positive (food-related) and negative (human-monkey conflict), affected vervet monkey ranging patterns in an urban environment. Over a year, we assessed the movement patterns of three groups of urban vervet monkeys over one year, analyzing both 95% and 50% kernel density estimates of their home ranges alongside daily path lengths and path sinuosities every month using generalized linear mixed models. Overall, we found that human interactions within the urban landscape affected all measures of ranging to some degree. The core home ranges of vervet monkeys increased with a higher rate of positive human encounters and their total home range increased with an interaction of both positive and negative human encounters. Furthermore, vervet monkeys were less likely to respond (i.e. increase daily path length or path sinuosity) to human aggression when food rewards were high, suggesting that effective management should focus on reducing human-food foraging opportunities. Our results highlight the complex interplay between positive and negative aspects of urban living and provide guidance for managers of human-nonhuman primate interactions

    A machine learning approach to predict perceptual decisions: an insight into face pareidolia

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    The perception of an external stimulus not only depends upon the characteristics of the stimulus but is also influenced by the ongoing brain activity prior to its presentation. In this work, we directly tested whether spontaneous electrical brain activities in prestimulus period could predict perceptual outcome in face pareidolia (visualizing face in noise images) on a trial-by-trial basis. Participants were presented with only noise images but with the prior information that some faces would be hidden in these images, while their electrical brain activities were recorded; participants reported their perceptual decision, face or no-face, on each trial. Using differential hemispheric asymmetry features based on large-scale neural oscillations in a machine learning classifier, we demonstrated that prestimulus brain activities could achieve a classification accuracy, discriminating face from no-face perception, of 75% across trials. The time–frequency features representing hemispheric asymmetry yielded the best classification performance, and prestimulus alpha oscillations were found to be mostly involved in predicting perceptual decision. These findings suggest a mechanism of how prior expectations in the prestimulus period may affect post-stimulus decision making

    Primates in the Urban Mosaic: Terminology, Flexibility, and Management

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    Continuous human expansion is affecting landscape composition, in particular through urbanisation. Wildlife persistence in the urban-mosaic is generally negatively affected; however, many primate species show behavioural plasticity and thrive in the urban-mosaic. Urban primates often show selective behaviours in the urban-mosaic, e.g. responses to anthropogenic food resources. However, as the urban-mosaic becomes more prominent and important for biodiversity conservation and management, clearer definitions and terminology used to describe the urban-mosaic are needed. Therefore, we use this chapter to review current definitions and suggest using the term ‘mosaic’ to discuss urban landscape ecology moving forward. Throughout our review, we consider the urban-mosaic complexity and emphasise the value of considering quantified anthropogenic disturbance and species-specific knowledge in urban primate ecology. We suggest that management focus on the multiple facets of the urban-mosaic, both human and primate derived, and discuss the benefits of biodiversity, conservation and human-primate coexistence

    Energy balance in patients with advanced NSCLC, metastatic melanoma and metastatic breast cancer receiving chemotherapy - A longitudinal study

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    Chemotherapy exerts a variable effect on nutritional status. It is not known whether loss of body fat or fat-free mass (FFM) during chemotherapy relates to diminished dietary intake, failure to meet elevated energy requirements, or to the presence of an acute-phase response. We sought to determine prospective measurements of body mass and composition, resting energy expenditure, energy and protein intake, and C-reactive protein over a course of chemotherapy in 82 patients with advanced cancer. There was a large dropout from the study. Prospective measurements were obtained in 19 patients with non-small-cell lung cancer (NSCLC), 12 with metastatic melanoma and 10 with metastatic breast cancer. There were significant increases in energy intake among patients with metastatic breast cancer, 873 (266–1480) kJ (mean 95% CI; P<0.01), and metastatic melanoma, 2513 (523–4503) kJ (P<0.01). Breast cancer patients gained percentage body fat over the course of treatment, 2.1 (0.8–3.5%). Gain or loss of body fat correlated to mean energy intake throughout chemotherapy in patients with NSCLC (Rs=0.751; P<0.01) and metastatic breast cancer (Rs=0.617; P<0.05). The ability to meet or exceed energy requirements led to gains in body fat among patients with metastatic breast cancer and NSCLC, but did not prevent loss of FFM in these groups
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