3,851 research outputs found

    Occupancy of wild southern pig-tailed macaques in intact and degraded forests in Peninsular Malaysia

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    Deforestation is a major threat to terrestrial tropical ecosystems, particularly in Southeast Asia where human activities have dramatic consequences for the survival of many species. However, responses of species to anthropogenic impact are highly variable. In order to establish effective conservation strategies, it is critical to determine a species’ ability to persist in degraded habitats. Here, we used camera trapping data to provide the first insights into the temporal and spatial distribution of southern pig-tailed macaques (Macaca nemestrina, listed as ‘Vulnerable’ by the IUCN) across intact and degraded forest habitats in Peninsular Malaysia, with a particular focus on the effects of clear-cutting and selective logging on macaque occupancy. Specifically, we found a 10% decline in macaque site occupancy in the highly degraded Pasoh Forest Reserve from 2013 to 2017. This may be strongly linked to the macaques’ sensitivity to intensive disturbance through clear-cutting, which significantly increased the probability that M. nemestrina became locally extinct at a previously occupied site. However, no clear relationship between moderate disturbance, i.e. selective logging, and the macaques’ local extinction probability as well as site occupancy was found in the Pasoh Forest Reserve and Belum-Temengor Forest Complex. Further, an identical age and sex structure of macaques in selectively logged and completely undisturbed habitat types within the Belum-Temengor Forest Complex indicated that the macaques did not show increased mortality or declining birth rates when exposed to selective logging. Overall, this suggests that low to moderately disturbed forests may still constitute valuable habitats that support viable populations of M. nemestrina, and thus need to be protected against further degradation. Our results emphasize the significance of population monitoring through camera trapping for understanding the ability of threatened species to cope with anthropogenic disturbance. This can inform species management plans and facilitate the development of effective conservation measures to protect biodiversity

    Correlation density matrices for 1- dimensional quantum chains based on the density matrix renormalization group

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    A useful concept for finding numerically the dominant correlations of a given ground state in an interacting quantum lattice system in an unbiased way is the correlation density matrix. For two disjoint, separated clusters, it is defined to be the density matrix of their union minus the direct product of their individual density matrices and contains all correlations between the two clusters. We show how to extract from the correlation density matrix a general overview of the correlations as well as detailed information on the operators carrying long-range correlations and the spatial dependence of their correlation functions. To determine the correlation density matrix, we calculate the ground state for a class of spinless extended Hubbard models using the density matrix renormalization group. This numerical method is based on matrix product states for which the correlation density matrix can be obtained straightforwardly. In an appendix, we give a detailed tutorial introduction to our variational matrix product state approach for ground state calculations for 1- dimensional quantum chain models. We show in detail how matrix product states overcome the problem of large Hilbert space dimensions in these models and describe all techniques which are needed for handling them in practice.Comment: 50 pages, 34 figures, to be published in New Journal of Physic

    HER2 testing in breast cancer: Opportunities and challenges

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    Human epidermal growth factor receptor 2 (HER2) is overexpressed in 15-25% of breast cancers, usually as a result of HER2 gene amplification. Positive HER2 status is considered to be an adverse prognostic factor. Recognition of the role of HER2 in breast cancer growth has led to the development of anti-HER2 directed therapy, with the humanized monoclonal antibody trastuzumab (Herceptin (R)) having been approved for the therapy of HER2-positive metastatic breast cancer. Clinical studies have further suggested that HER2 status can provide important information regarding success or failure of certain hormonal therapies or chemotherapies. As a result of these developments, there has been increasing demand to perform HER2 testing on current and archived breast cancer specimens. This article reviews the molecular background of HER2 function, activation and inhibition as well as current opinions concerning its role in chemosensitivity and interaction with estrogen receptor biology. The different tissue-based assays used to detect HER2 amplification and overexpression are discussed with respect to their advantages and disadvantages, when to test (at initial diagnosis or pre-treatment), where to test (locally or centralized) and the need for quality assurance to ensure accurate and valid testing results

    Geographically touring the eastern bloc: British geography, travel cultures and the Cold War

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    This paper considers the role of travel in the generation of geographical knowledge of the eastern bloc by British geographers. Based on oral history and surveys of published work, the paper examines the roles of three kinds of travel experience: individual private travels, tours via state tourist agencies, and tours by academic delegations. Examples are drawn from across the eastern bloc, including the USSR, Poland, Romania, East Germany and Albania. The relationship between travel and publication is addressed, notably within textbooks, and in the Geographical Magazine. The study argues for the extension of accounts of cultures of geographical travel, and seeks to supplement the existing historiography of Cold War geography

    Thresholds for clinical importance were defined for the European Organisation for Research and Treatment of Cancer Computer Adaptive Testing Core-an adaptive measure of core quality of life domains in oncology clinical practice and research

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    Objectives The aim of this article was to establish thresholds for clinical importance (TCIs) for the European Organisation for Research and Treatment of Cancer (EORTC) Computer Adaptive Testing (CAT) Core measure, the new adaptive version of the EORTC QLQ-C30. Study Design and Setting For our diagnostic study, we recruited cancer patients with mixed diagnoses and treatments from six European countries. Patients completed the EORTC CAT Core and a questionnaire with anchor items assessing criteria for clinical importance (limitations in everyday life, need for help/care, and worries by the patient/family/partner) for each EORTC CAT Core domain. We used a binary variable summarizing the anchor items for determining TCIs and for calculating the area under the curve (AUC) in receiving operator characteristic analysis as a measure of diagnostic accuracy. Results Using data from 498 cancer patients (mean age 60.4 years, 55.2% women), we established TCIs for the 14 domains of the EORTC CAT Core. Median AUC across domains was 0.93 (range 0.84–0.94). Median sensitivity and specificity of the TCIs were 0.91 (range 0.80–0.96) and 0.77 (range 0.66–0.84), respectively. TCIs and AUCs were largely consistent across patient groups. Conclusion We have generated TCIs for the 14 functional health and symptom domains of the EORTC CAT Core. The EORTC CAT Core showed high diagnostic accuracy in identifying clinically important symptoms and functional impairments
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