251 research outputs found

    The CCD/Transit Instrument (CTI) data-analysis system

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    The automated software system for archiving, analyzing, and interrogating data from the CCD/Transit Instrument (CTI) is described. The CTI collects up to 450 Mbytes of image-data each clear night in the form of a narrow strip of sky observed in two colors. The large data-volumes and the scientific aims of the project make it imperative that the data are analyzed within the 24-hour period following the observations. To this end a fully automatic and self evaluating software system has been developed. The data are collected from the telescope in real-time and then transported to Tucson for analysis. Verification is performed by visual inspection of random subsets of the data and obvious cosmic rays are detected and removed before permanent archival is made to the optical disc. The analysis phase is performed by a pair of linked algorithms, one operating on the absolute pixel-values and the other on the spatial derivative of the data. In this way both isolated and merged images are reliably detected in a single pass. In order to isolate the latter algorithm from the effects of noise spikes a 3x3 Hanning filter is applied to the raw data before the analysis is run. The algorithms reduce the input pixel-data to a database of measured parameters for each image which has been found. A contrast filter is applied in order to assign a detection-probability to each image and then x-y calibration and intensity calibration are performed using known reference stars in the strip. These are added to as necessary by secondary standards boot-strapped from the CTI data itself. The final stages involve merging the new data into the CTI Master-list and History-list and the automatic comparison of each new detection with a set of pre-defined templates in parameter-space to find interesting objects such as supernovae, quasars and variable stars. Each stage of the processing from verification to interesting image selection is performed under a data-logging system which both controls the pipe-lining of data through the system and records key performance monitor parameters which are built into the software. Furthermore, the data from each stage are stored in databases to facilitate evaluation, and all stages offer the facility to enter keyword-indexed free-format text into the data-logging system. In this way a large measure of certification is built into the system to provide the necessary confidence in the end results

    Continuity or change in business representation in Britain? An assessment of the Heseltine initiatives of the 1990s

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    Britain has a fragmented, overlapping, and underresourced system of business representation. Attempts at reform, however, have proved difficult and largely unsuccessful. A coherent and logical system is relevant, in terms of both an effective dialogue between government and business, and the promotion of competitiveness and productivity. Through interviews and archival evidence, I look at how government has attempted to reform business associations. The main focus is the Heseltine initiatives of the 1990s: I outline the various initiatives taken, reveal the extent to which policy represented continuity or change, and consider whether the initiatives were effective. I show that they had a degree of success but that they would have made greater impact if they had been sustained over a longer period of time. A consideration of the historical context, moreover, suggests there may be limits to the role of government intervention in business association reform

    Autophagy in dental tissues: a double-edged sword

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    Biotechnology and Biological Sciences Research Council [BB/L02392X/1]SCI(E)PubMedEDITORIAL [email protected]

    Institutional logics and interorganizational learning in technological arenas: Evidence from standard-setting organizations in the mobile handset industry

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    © 2015, INFORMS. Conceptualizing standard-setting organizations (SSOs) as technological arenas within which firms from different countries interact and learn, we offer insights into the interplay between firms' institutional logics and their interorganizational learning outcomes. We suggest that firms' interorganizational learning is embedded in their macrolevel country contexts, characterized by more corporatist versus less corporatist (pluralist) institutional logics. Whereas corporatism spurs coordinated approaches, pluralism engenders competitive interactions that affect the extent to which firms span organizational and technological boundaries and learn from each other. We test our theory using longitudinal analysis of 181 dyads involving 26 firms participating in 17 SSOs in the global mobile handset industry. We find that interorganizational learning, as measured by patent citations, involving corporatist firm dyads significantly increases when the dominant logic within the arena is also corporatist. By making cooperative schemas more accessible, a dominant corporatist logic also enhances interorganizational learning across technologically distant dyads. When a pluralist logic dominates the arena, corporatist dyads learn less because firms in the dyad activate a contradictory logic that decouples them from their natural processes for interorganizational learning. These findings highlight the implications of institutional logics for interorganizational learning outcomes and provide insights into how firms attend to institutional contradictions in arenas that provide opportunities for interorganizational learning

    MRI compared to conventional diagnostic work-up in the detection and evaluation of invasive lobular carcinoma of the breast: a review of existing literature

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    Item does not contain fulltextPURPOSE: The clinical diagnosis and management of invasive lobular carcinoma (ILC) of the breast presents difficulties. Magnetic resonance imaging (MRI) has been proposed as the imaging modality of choice for the evaluation of ILC. Small studies addressing different aspects of MRI in ILC have been presented but no large series to date. To address the usefulness of MRI in the work-up of ILC, we performed a review of the currently published literature. MATERIALS AND METHODS: We performed a literature search using the query "lobular AND (MRI OR MR OR MRT OR magnetic)" in the Cochrane library, PubMed and scholar.google.com, to retrieve all articles that dealt with the use of MRI in patients with ILC. We addressed sensitivity, morphologic appearance, correlation with pathology, detection of additional lesions, and impact of MRI on surgery as different endpoints. Whenever possible we performed meta-analysis of the pooled data. RESULTS: Sensitivity is 93.3% and equal to overall sensitivity of MRI for malignancy in the breast. Morphologic appearance is highly heterogeneous and probably heavily influenced by interreader variability. Correlation with pathology ranges from 0.81 to 0.97; overestimation of lesion size occurs but is rare. In 32% of patients, additional ipsilateral lesions are detected and in 7% contralateral lesions are only detected by MRI. Consequently, MRI induces change in surgical management in 28.3% of cases. CONCLUSION: This analysis indicates MRI to be valuable in the work-up of ILC. It provides additional knowledge that cannot be obtained by conventional imaging modalities which can be helpful in patient treatment

    Revisiting the association between candidal infection and carcinoma, particularly oral squamous cell carcinoma

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    Background: Tobacco and alcohol are risk factors associated with cancer of the upper aerodigestive tract, but increasingly the role of infection and chronic inflammation is recognized as being significant in cancer development. Bacteria, particularly Helicobacter pylori, and viruses such as members of the human papilloma virus family and hepatitis B and C are strongly implicated as etiological factors in certain cancers. There is less evidence for an association between fungi and cancer, although it has been recognized for many years that white patches on the oral mucosa, which are infected with Candida, have a greater likelihood of undergoing malignant transformation than those that are not infected. Objective: This article reviews the association between the development of oral squamous cell carcinoma in potentially malignant oral lesions with chronic candidal infection and describes mechanisms that may be involved in Candida-associated malignant transformation

    Government Influence on Patient Organizations

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    Patient organizations increasingly play an important role in health care decision-making in Western countries. The Netherlands is one of the countries where this trend has gone furthest. In the literature some problems are identified, such as instrumental use of patient organizations by care providers, health insurers and the pharmaceutical industry. To strengthen the position of patient organizations government funding is often recommended as a solution. In this paper we analyze the ties between Dutch government and Dutch patient organizations to learn more about the effects of such a relationship between government and this part of civil society. Our study is based on official government documents and existing empirical research on patient organizations. We found that government influence on patient organizations has become quite substantial with government influencing the organizational structure of patient organizations, the activities these organizations perform and even their ideology. Financing patient organizations offers the government an important means to hold them accountable. Although the ties between patient organizations and the government enable the former to play a role that can be valued as positive by both parties, we argue that they raise problems as well which warrant a discussion on how much government influence on civil society is acceptable

    Clientelistic networks and local corruption: Evidence from Western Crete DIMITRIOS CHRISTOPOULOS

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    In this article, the attitudes and interaction of local political and business elites in western Crete are examined by means of an attitudinal survey, triangulated with data from in-depth interviews, conducted between July and October 1991. The data examined indicate that the endemic prevalence of clientelistic networks creates the background for corruption, although evidence of corrupt practice is not strong. In this analysis it is presumed that the attitudes and perceptions of key actors are affected by a definition of corruption that is relevant to their particular civil society alone. Data analyzed here suggest that local élite attitudes towards corruption are not perceived to affect the standards of conduct at the local level. It can also be deduced that if corruption is linked to the problems of administrative efficiency and economic development of the region, these can be related to vertical clientelistic networks with the national centre

    Pathogenesis of Candida albicans Infections in the Alternative Chorio-Allantoic Membrane Chicken Embryo Model Resembles Systemic Murine Infections

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    Alternative models of microbial infections are increasingly used to screen virulence determinants of pathogens. In this study, we investigated the pathogenesis of Candida albicans and C. glabrata infections in chicken embryos infected via the chorio-allantoic membrane (CAM) and analyzed the virulence of deletion mutants. The developing immune system of the host significantly influenced susceptibility: With increasing age, embryos became more resistant and mounted a more balanced immune response, characterized by lower induction of proinflammatory cytokines and increased transcription of regulatory cytokines, suggesting that immunopathology contributes to pathogenesis. While many aspects of the chicken embryo response resembled murine infections, we also observed significant differences: In contrast to systemic infections in mice, IL-10 had a beneficial effect in chicken embryos. IL-22 and IL-17A were only upregulated after the peak mortality in the chicken embryo model occurred; thus, the role of the Th17 response in this model remains unclear. Abscess formation occurs frequently in murine models, whereas the avian response was dominated by granuloma formation. Pathogenicity of the majority of 15 tested C. albicans deletion strains was comparable to the virulence in mouse models and reduced virulence was associated with significantly lower transcription of proinflammatory cytokines. However, fungal burden did not correlate with virulence and for few mutants like bcr1Δ and tec1Δ different outcomes in survival compared to murine infections were observed. C. albicans strains locked in the yeast stage disseminated significantly more often from the CAM into the embryo, supporting the hypothesis that the yeast morphology is responsible for dissemination in systemic infections. These data suggest that the pathogenesis of C. albicans infections in the chicken embryo model resembles systemic murine infections but also differs in some aspects. Despite its limitations, it presents a useful alternative tool to pre-screen C. albicans strains to select strains for subsequent testing in murine models

    Genetic aspects of dental disorders

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    The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.This paper reviews past and present applications of quantitative and molecular genetics to dental disorders. Examples are given relating to craniofacial development (including malocclusion), oral supporting tissues (including periodontal diseases) and dental hard tissues (including defects of enamel and dentine as well as dental caries). Future developments and applications to clinical dentistry are discussed. Early investigations confirmed genetic bases to dental caries, periodontal diseases and malocclusion, but research findings have had little impact on clinical practice. The complex multifactorial aetiologies of these conditions, together with methodological problems, have limited progress until recently. Present studies are clarifying previously unrecognized genetic and phenotypic heterogeneities and attempting to unravel the complex interactions between genes and environment by applying new statistical modelling approaches to twin and family data. linkage studies using highly polymorphic DNA markers are providing a means of locating candidate genes, including quantitative trait loci (QTL). In future, as knowledge increases: it should be possible to implement preventive strategies for those genetically-predisposed individuals who are identified-predisposed individuals who are identified to be at risk.Grant C. Townsend, Michael J. Aldred and P. Mark Bartol
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