475 research outputs found

    A CAUSAL ANALYSIS OF THE DEFENCE-GROWTH RELATIONSHIPS: EVIDENCE FROM THE BALKANS

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    The causal relationships between military burden and economic growth have attracted considerable interest of academics, scholars and practitioners during the last three decades. This survey is hoping to contribute to the existing pool of literature by investigating the causal links between defence spending and economic growth for three developing Balkan countries (Bulgaria, Romania and Albania) and their mature counterpart in the Balkan Peninsula (Greece) during the period 1988-2009. Empirical results imply that there are no bilateral links between the tested variables for any of the tested countries. However, findings indicate the presence of one-way causal links running from military expenditures to GDP only for Bulgaria and Albania, implying the significant impact of defence burden on growth for these countries. On the other hand, empirical results for Greece and Romania suggest that defence spending and GDP growth are independent, which favours neutrality hypothesis. Nevertheless, it should be mentioned that we would expect to find significant links especially in the case of Greece, due to the fact that the country presents the highest defence expenditures in the Balkan region for the last fifteen years. These contradictory results could be due to different levels of maturity between the tested countries but it could also be attributed to temporary changes of accounting practises (i.e. recording expenses when military material was ordered rather than received, as evidenced in the case of Greece in the late 1990’s by government officials). These accounting changes could be the obstacle in some cases (e.g. Greece) to provide empirical evidence of the links between defence burden and economic growth

    Extracting causal rules from spatio-temporal data

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    The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-23374-1_2This paper is concerned with the problem of detecting causality in spatiotemporal data. In contrast to most previous work on causality, we adopt a logical rather than a probabilistic approach. By defining the logical form of the desired causal rules, the algorithm developed in this paper searches for instances of rules of that form that explain as fully as possible the observations found in a data set. Experiments with synthetic data, where the underlying causal rules are known, show that in many cases the algorithm is able to retrieve close approximations to the rules that generated the data. However, experiments with real data concerning the movement of fish in a large Australian river system reveal significant practical limitations, primarily as a consequence of the coarse granularity of such movement data. In response, instead of focusing on strict causation (where an environmental event initiates a movement event), further experiments focused on perpetuation (where environmental conditions are the drivers of ongoing processes of movement). After retasking to search for a different logical form of rules compatible with perpetuation, our algorithm was able to identify perpetuation rules that explain a significant proportion of the fish movements. For example, approximately one fifth of the detected long-range movements of fish over a period of six years were accounted for by 26 rules taking account of variations in water-level alone.EPSRCAustralian Research Council (ARC) under the Discovery Projects Schem

    Graft Choice and the Incidence of Osteoarthritis After Anterior Cruciate Ligament Reconstruction: A Causal Analysis From a Cohort of 541 Patients

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    BACKGROUND: Anterior cruciate ligament (ACL) reconstruction is important to prevent knee osteoarthritis. Neither of the 2 most common graft techniques-the patellar tendon (PT) or hamstring tendon (HS) graft-has demonstrated superiority in terms of the long-term osteoarthritis rate. HYPOTHESIS: Based on the International Knee Documentation Committee (IKDC) radiographic grading system, PT grafts decrease the incidence of osteoarthritis by providing better knee stability as compared with HS grafts over 12 years of follow-up. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All adults with a first ACL rupture who underwent surgery with a PT or HS graft technique between January 2002 and December 2003 were included in the 2014 French Society of Orthopedic Surgery and Traumatology Symposium database. Baseline characteristics were collected. The primary endpoint was the occurrence of moderate to severe osteoarthritis in each group. The secondary endpoints included clinical subjective evaluations by the IKDC score and Knee injury and Osteoarthritis Outcome Score. To control the differences in baseline characteristics, the data were analyzed with propensity score matching. RESULTS: In the cohort, 541 patients from 18 centers were included: 311 PT and 230 HS ACL reconstructions. The baseline characteristics were similar after inverse probability weighting treatment (IPWT). The occurrence of osteoarthritis was similar after IPWT (19.3% for PT and 19.6% for HS, P = .94). Age at surgery >29 years and IKDC osteoarthritis stage B at the index surgery were identified as risk factors for moderate to severe osteoarthritis. Most functional outcomes were significantly higher in the HS group; however, the difference between groups remained <10 points. Of the 106 patients who needed a medial meniscectomy, the proportion of patients with moderate to severe osteoarthritis was much higher in the HS group (43.5% vs 18.3%, P = .006). However, after IPWT, the difference was not statistically significant. CONCLUSION: At 12 years of follow-up, neither graft technique was superior to the other in terms of the rate of osteoarthritis

    Analysis of Qualitative Variables

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    A variety of qualitative dependent variable models are surveyed with attention focused on the computational aspects of their analysis. The models covered include single equation dichotomous models; single equation polychotomous models with unordered, ordered, and sequential variables; and simultaneous equation models. Care is taken to illucidate the nature of the suggested "full information" and "limited information" approaches to the simultaneous equation models and the formulation of recursive and causal chain models.

    Intestinal barrier tightening by a cell-penetrating antibody to Bin1, a candidate target for immunotherapy of ulcerative colitis.

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    Patients afflicted with ulcerative colitis (UC) are at increased risk of colorectal cancer. While its causes are not fully understood, UC is associated with defects in colonic epithelial barriers that sustain inflammation of the colon mucosa caused by recruitment of lymphocytes and neutrophils into the lamina propria. Based on genetic evidence that attenuation of the bridging integrator 1 (Bin1) gene can limit UC pathogenicity in animals, we have explored Bin1 targeting as a therapeutic option. Early feasibility studies in the dextran sodium sulfate mouse model of experimental colitis showed that administration of a cell-penetrating Bin1 monoclonal antibody (Bin1 mAb 99D) could prevent lesion formation in the colon mucosa in part by preventing rupture of lymphoid follicles. In vivo administration of Bin1 mAb altered tight junction protein expression and cecal barrier function. Strikingly, electrophysiology studies in organ cultures showed that Bin1 mAb could elevate resistance and lowe

    The Apt Word

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    Information Seeking and Knowledge Acquisition Behaviors of Young Information Systems Workers: Preliminary Analysis

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    The rapid growth of IT capital investments requires the corresponding development of IS human resources to effectively implement and apply the new technologies. This study addresses a critical, emerging research area for the development of young IS knowledge workers, which is key to providing the human infrastructure for successful implementation of IT in the future. Drawing upon the theory and methodology from several different lines of prior research, this current research project is designed to study the relationship between information seeking/knowledge acquisition behaviors and job performance of young IS workers. This paper describes a current research project in progress which investigates the information seeking and knowledge acquisition behavior of young IS workers. It is proposed that an understanding of how young IS workers approach their work and the factors facilitating or limiting their task learning process and job performance could lead to important findings affecting research, education and industry practice

    A framework for the design, conduct and interpretation of randomised controlled trials in the presence of treatment changes.

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    BACKGROUND: When a randomised trial is subject to deviations from randomised treatment, analysis according to intention-to-treat does not estimate two important quantities: relative treatment efficacy and effectiveness in a setting different from that in the trial. Even in trials of a predominantly pragmatic nature, there may be numerous reasons to consider the extent, and impact on analysis, of such deviations from protocol. Simple methods such as per-protocol or as-treated analyses, which exclude or censor patients on the basis of their adherence, usually introduce selection and confounding biases. However, there exist appropriate causal estimation methods which seek to overcome these inherent biases, but these methods remain relatively unfamiliar and are rarely implemented in trials. METHODS: This paper demonstrates when it may be of interest to look beyond intention-to-treat analysis for answers to alternative causal research questions through illustrative case studies. We seek to guide trialists on how to handle treatment changes in the design, conduct and planning the analysis of a trial; these changes may be planned or unplanned, and may or may not be permitted in the protocol. We highlight issues that must be considered at the trial planning stage relating to: the definition of nonadherence and the causal research question of interest, trial design, data collection, monitoring, statistical analysis and sample size. RESULTS AND CONCLUSIONS: During trial planning, trialists should define their causal research questions of interest, anticipate the likely extent of treatment changes and use these to inform trial design, including the extent of data collection and data monitoring. A series of concise recommendations is presented to guide trialists when considering undertaking causal analyses

    Paper or Plastic?

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    Letter to the Editor
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