1,734 research outputs found

    Efficiency of free energy calculations of spin lattices by spectral quantum algorithms

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    Quantum algorithms are well-suited to calculate estimates of the energy spectra for spin lattice systems. These algorithms are based on the efficient calculation of the discrete Fourier components of the density of states. The efficiency of these algorithms in calculating the free energy per spin of general spin lattices to bounded error is examined. We find that the number of Fourier components required to bound the error in the free energy due to the broadening of the density of states scales polynomially with the number of spins in the lattice. However, the precision with which the Fourier components must be calculated is found to be an exponential function of the system size.Comment: 9 pages, 4 figures; corrected typographical and minor mathematical error

    Clinical characteristics and management of cancer-associated acute venous thromboembolism: findings from the MASTER Registry.

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    Background: Clinical characteristics and management of acute deep vein thrombosis and pulmonary embolism (PE) have been reported to be different in patients with and without cancer. The aim of this paper was to provide information on clinical characteristics and management of acute venous thromboembolism in patients with cancer by means of a large prospective registry. Design and Methods: MASTER is a multicenter registry of consecutively recruited patients with symptomatic, objectively confirmed, acute venous thromboembolism. Information about clinical characteristics and management was collected by an electronic data network at the time of the index event. Results: A total of 2119 patients were enrolled, of whom 424 (20%) had cancer. The incidence of bilateral lower limb deep vein thrombosis was significantly higher in patients with cancer than in patients without cancer (8.5% versus 4.6%; p<0.01), as were the rates of iliocaval thombosis (22.6% versus 14%; p<0.001), and upper limb deep vein thrombosis (9.9% versus 4.8%; p<0.001). Major bleeding (3.3% versus 1.1%; p=0.001), in-hospital treatment (73.3% versus 66.6%; p=0.02) and inferior vena cava filter implantation (7.3% versus 4.1%; p=0.005) were significantly more frequent in patients with cancer, in whom oral anticoagulants were less often used (64.2% versus 82%; p<0.0001). Conclusions: The clinical presentation of acute venous thromboembolism is different and often more extensive in cancer patients than in patients free from malignancy. Moreover, the management of the acute phase of venous thromboembolism is more problematic in cancer patients, especially because of a higher rate of major bleeding and the need for implantation of inferior vena cava filters

    Towards the development of an Inter-Cultural Scale to Measure Trust in Automation

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    Trust is conceived as an attitude leading to intentions resulting in user actions involving automation. It is generally believed that trust is dynamic and that a user’s prior experience with automation affects future behavior indirectly through causing changes in trust. Additionally, individual differences and cultural factors have been frequently cited as the contributors to influencing trust beliefs about using and monitoring automation. The presented research focuses on modeling human’s trust when interacting with automated systems across cultures. The initial trust assessment instrument, comprising 110 items along with 2 perceptions (general vs. specific use of automation), has been empirically validated. Detailed results comparing items and dimensionality with our new pooled measure will be presented

    Species recovery in the united states: Increasing the effectiveness of the endangered species act

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    The Endangered Species Act (ESA) has succeeded in shielding hundreds of species from extinction and improving species recovery over time. However, recovery for most species officially protected by the ESA - i.e., listed species-has been harder to achieve than initially envisioned. Threats to species are persistent and pervasive, funding has been insufficient, the distribution of money among listed species is highly uneven, and at least 10 times more species than are actually listed probably qualify for listing. Moreover, many listed species will require ongoing management for the foreseeable future to protect them from persistent threats. Climate change will exacerbate this problem and increase both species risk and management uncertainty, requiring more intensive and controversial management strategies to prevent species from going extinct

    Cross-Disciplinarity in the Advance of Antarctic Ecosystem Research

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    The biodiversity, ecosystem services and climate variability of the Antarctic continent, and the Southern Ocean are major components of the whole Earth system. Antarctic ecosystems are driven more strongly by the physical environment than many other marine and terrestrial ecosystems. As a consequence, to understand ecological functioning, cross-disciplinary studies are especially important in Antarctic research. The conceptual study presented here is based on a workshop initiated by the Research Programme Antarctic Thresholds - Ecosystem Resilience and Adaption of the Scientific Committee on Antarctic Research, which focused on challenges in identifying and applying cross-disciplinary approaches in the Antarctic. Novel ideas, and first steps in their implementation, were clustered into eight themes, ranging from scale problems, risk maps, organism and ecosystem responses to multiple environmental changes, to evolutionary processes. Scaling models and data across different spatial and temporal scales were identified as an overarching challenge. Approaches to bridge gaps in the research programmes included multi-disciplinary monitoring, linking biomolecular findings and simulated physical environments, as well as integrative ecological modelling. New strategies in academic education are proposed. The results of advanced cross-disciplinary approaches can contribute significantly to our knowledge of ecosystem functioning, the consequences of climate change, and to global assessments that ultimately benefit humankind

    Computational expression deconvolution in a complex mammalian organ

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    BACKGROUND: Microarray expression profiling has been widely used to identify differentially expressed genes in complex cellular systems. However, while such methods can be used to directly infer intracellular regulation within homogeneous cell populations, interpretation of in vivo gene expression data derived from complex organs composed of multiple cell types is more problematic. Specifically, observed changes in gene expression may be due either to changes in gene regulation within a given cell type or to changes in the relative abundance of expressing cell types. Consequently, bona fide changes in intrinsic gene regulation may be either mimicked or masked by changes in the relative proportion of different cell types. To date, few analytical approaches have addressed this problem. RESULTS: We have chosen to apply a computational method for deconvoluting gene expression profiles derived from intact tissues by using reference expression data for purified populations of the constituent cell types of the mammary gland. These data were used to estimate changes in the relative proportions of different cell types during murine mammary gland development and Ras-induced mammary tumorigenesis. These computational estimates of changing compartment sizes were then used to enrich lists of differentially expressed genes for transcripts that change as a function of intrinsic intracellular regulation rather than shifts in the relative abundance of expressing cell types. Using this approach, we have demonstrated that adjusting mammary gene expression profiles for changes in three principal compartments – epithelium, white adipose tissue, and brown adipose tissue – is sufficient both to reduce false-positive changes in gene expression due solely to changes in compartment sizes and to reduce false-negative changes by unmasking genuine alterations in gene expression that were otherwise obscured by changes in compartment sizes. CONCLUSION: By adjusting gene expression values for changes in the sizes of cell type-specific compartments, this computational deconvolution method has the potential to increase both the sensitivity and specificity of differential gene expression experiments performed on complex tissues. Given the necessity for understanding complex biological processes such as development and carcinogenesis within the context of intact tissues, this approach offers substantial utility and should be broadly applicable to identifying gene expression changes in tissues composed of multiple cell types

    Comparative Assessment of Microbial Air Contamination in Labor and Postnatal Ward at Mzuzu Central Hospital

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    Nosocomial infections are rapidly becoming a burden especially in developing countries. Neonates are part of the individuals who are at a high risk and mostly affected. Environmental contamination is one of the key agents of these infections. This study aimed to comparatively assess the microbial air contamination before and after cleaning in the labor and postnatal ward at Mzuzu Central Hospital. A comparative study design was employed, with a sample size of 60 paired culture plates (60 MacConkey agar plates and 60 Blood agar plates). Passive technique of air sampling was used to sample air there after 24 hours of culturing and isolation on blood agar and MacConkey agar for identification and quantification of bacterial colonies. Room observations were also done. There was a significant difference between contaminations before and after cleaning, only when MacConkey agar was used. The microorganisms that were identified include; Staphylococci aureus, Klebsiella, coagulase negative staphylococci and non-hemolytic streptococcus. Factors found to contribute to air contamination were, the size of the rooms, traffic of people in a room and number of people present in a room. This study has identified the hazard that these two wards are containing and suggests interventions to avoid nosocomial infections in the neonates
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