664 research outputs found

    Evaluating camera trapping as a method for estimating cheetah abundance in ranching areas

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    In order to accurately assess the status of the cheetah Acinonyx jubatus it is necessary to obtain data on numbers and demographic trends. However, cheetahs are notoriously difficult to survey because they occur at very low population densities and are often shy and elusive. In South Africa the problem is further complicated in areas where land is privately owned, restricting access, with dense bush and cheetahs that are frequently persecuted. Cheetahs are individually identifiable by their unique spot patterns, making them ideal candidates for capture-recapture surveys. Photographs of cheetahs were obtained using four camera traps placed successively at a total of 12 trap locations in areas of known cheetah activity within a 300 km2 area in the Thabazimbi district of the Limpopo Province. During 10 trapping periods, five different cheetahs were photographed. These results were used to generate capture histories for each cheetah and the data were analysed using the capture-recapture software package CAPTURE. Closure tests indicated that the population was closed (P = 0.056). The Mh model was used to deal with possible heterogeneous capture probabilities among individual cheetahs. Closure tests did not reject the model assumption of population closure (P = 0.056). The Mh model produced a capture probability of 0.17 with an estimate of 6-14 cheetahs (P = 0.95) and a mean population size of seven cheetahs (S.E. = 1.93). These results are promising and will be improved with employment of more camera traps and sampling a larger area

    The production of human-wildlife conflict: a political animal geography of encounter

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    This study examines how transformations of a regional rural economy have produced new geographies of en- counter between agricultural communities, their livestock, and carnivores surrounding Bandipur National Park in Karnataka, India. We analyze state discourses of human-wildlife conflict alongside the perspectives of rural agricultural communities about changes in human-wildlife interactions. Our study shows how state narratives about human-wildlife conflict mask more foundational changes in the livelihood strategies of agricultural vil- lages in response both to park management and regional economic transformations, and how these changes are inherently woven into the production of new geographies of human-wildlife encounter. Our results suggest declining tolerance for injury and death of cattle by carnivores represents the cumulative impacts of a trans- formation of the livestock economy and more aggressive protected area management strategies. This research also suggests how political ecology can maintain its commitments to social justice while becoming more attuned to animals as political actors

    Bayesian inference in camera trapping studies for a class of spatial capture-recapture models

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    We develop a class of models for inference about abundance or density using spatial capture-recapture data from studies based on camera trapping and related methods. The model is a hierarchical model composed of two components: a point process model describing the distribution of individuals in space (or their home range centers) and a model describing the observation of individuals in traps. We suppose that trap- and individual-specific capture probabilities are a function of distance between individual home range centers and trap locations. We show that the models can be regarded as generalized linear mixed models, where the individual home range centers are random effects. We adopt a Bayesian framework for inference under these models using a formulation based on data augmentation. We apply the models to camera trapping data on tigers from the Nagarahole Reserve, India, collected over 48 nights in 2006. For this study, 120 camera locations were used, but cameras were only operational at 30 locations during any given sample occasion. Movement of traps is common in many camera-trapping studies and represents an important feature of the observation model that we address explicitly in our application

    Phylogenetics and biogeography of a spectacular Old World radiation of butterflies: the subtribe Mycalesina (Lepidoptera: Nymphalidae: Satyrini)

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    Background: Butterflies of the subtribe Mycalesina (Nymphalidae: Satyrinae) are important model organisms in ecology and evolution. This group has radiated spectacularly in the Old World tropics and presents an exciting opportunity to better understand processes of invertebrate rapid radiations. However, the generic-level taxonomy of the subtribe has been in a constant state of flux, and relationships among genera are unknown. There are six currently recognized genera in the group. Mycalesis, Lohora and Nirvanopsis are found in the Oriental region, the first of which is the most speciose genus among mycalesines, and extends into the Australasian region. Hallelesis and Bicyclus are found in mainland Africa, while Heteropsis is primarily Madagascan, with a few species in Africa. We infer the phylogeny of the group with data from three genes (total of 3139 bp) and use these data to reconstruct events in the biogeographic history of the group. Results: The results indicate that the group Mycalesina radiated rapidly around the Oligocene-Miocene boundary. Basal relationships are unresolved, but we recover six well-supported clades. Some species of Mycalesis are nested within a primarily Madagascan clade of Heteropsis, while Nirvanopsis is nested within Lohora. The phylogeny suggests that the group had its origin either in Asia or Africa, and diversified through dispersals between the two regions, during the late Oligocene and early Miocene. The current dataset tentatively suggests that the Madagascan fauna comprises two independent radiations. The Australasian radiation shares a common ancestor derived from Asia. We discuss factors that are likely to have played a key role in the diversification of the group. Conclusions: We propose a significantly revised classification scheme for Mycalesina. We conclude that the group originated and radiated from an ancestor that was found either in Asia or Africa, with dispersals between the two regions and to Australasia. Our phylogeny paves the way for further comparative studies on this group that will help us understand the processes underlying diversification in rapid radiations of invertebrates.13 page(s

    Tigers on trails: occupancy modeling for cluster sampling

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    Occupancy modeling focuses on inference about the distribution of organisms over space, using temporal or spatial replication to allow inference about the detection process. Inference based on spatial replication strictly requires that replicates be selected randomly and with replacement, but the importance of these design requirements is not well understood. This paper focuses on an increasingly popular sampling design based on spatial replicates that are not selected randomly and that are expected to exhibit Markovian dependence. We develop two new occupancy models for data collected under this sort of design, one based on an underlying Markov model for spatial dependence and the other based on a trap response model with Markovian detections. We then simulated data under the model for Markovian spatial dependence and fit the data to standard occupancy models and to the two new models. Bias of occupancy estimates was substantial for the standard models, smaller for the new trap response model, and negligible for the new spatial process model. We also fit these models to data from a large-scale tiger occupancy survey recently conducted in Karnataka State, southwestern India. In addition to providing evidence of a positive relationship between tiger occupancy and habitat, model selection statistics and estimates strongly supported the use of the model with Markovian spatial dependence. This new model provides another tool for the decomposition of the detection process, which is sometimes needed for proper estimation and which may also permit interesting biological inferences. In addition to designs employing spatial replication, we note the likely existence of temporal Markovian dependence in many designs using temporal replication. The models developed here will be useful either directly, or with minor extensions, for these designs as well. We believe that these new models represent important additions to the suite of modeling tools now available for occupancy estimation in conservation monitoring. More generally, this work represents a contribution to the topic of cluster sampling for situations in which there is a need for specific modeling (e.g., reflecting dependence) for the distribution of the variable(s) of interest among subunits

    The Hanging/hanged Patient and Relevance to Pre-hospital Care

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    Death and injury from hanging is a complex situation, which requires careful and appropriate assessment and management in the pre-hospital environment. It is arguably an area of limited understanding and therefore may not be assessed and managed in the most effective manner. Most hanged/hanging patients will be found in their homes, rather than in institutions. It could be argued that due to prevalence as a suicide method, the majority of pre-hospital ambulance service staff will be responded to at least one hanged or hanging patient within their careers, thus a greater understanding will benefit both clinician and patient. Patients who attempt or achieve suicide will rarely achieve fracturing the spine and severing the spinal cord, bringing into question the requirement for the traditional cervical collar and spinal immobilisation techniques. Death from asphyxiation and carotid/vagal reflex require consideration and management as does raised ICP, which is likely to occur

    Zdvue: Prioritization of JavaScript attacks to discover new vulnerabilities

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    ABSTRACT Malware writers are constantly looking for new vulnerabilities to exploit in popular software applications. A successful exploit of a previously unknown vulnerability, that evades state-of-the art anti-virus and intrusion-detection systems is called a zero-day vulnerability. JavaScript is a popular vehicle for testing and delivering attacks through drive-by downloads on web clients. Failed attack attempts leave traces of suspicious activity on victim machines. We present ZDVUE, a tool for automatic prioritization of suspicious JavaScript traces, which can lead to early detection of potential zeroday vulnerabilities. Our algorithm uses a combination of correlation analysis and mixture modeling for fast and robust prioritization of suspicious JavaScript samples.On data collected between June and November 2009, ZDVUE identified a new zero-day vulnerability and its variant in its top results, as well as revealed many new anti-virus signatures. ZDVUE is used in our organization on a routine basis to automatically filter, analyze, and prioritize thousands of downloaded JavaScript files, for information to update anti-virus signatures and to find new zero-day vulnerabilities

    WiseEye: next generation expandable and programmable camera trap platform for wildlife research

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    Funding: The work was supported by the RCUK Digital Economy programme to the dot.rural Digital Economy Hub; award reference: EP/G066051/1. The work of S. Newey and RJI was part funded by the Scottish Government's Rural and Environment Science and Analytical Services (RESAS). Details published as an Open Source Toolkit, PLOS Journals at: http://dx.doi.org/10.1371/journal.pone.0169758Peer reviewedPublisher PD
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