4,996 research outputs found

    Investigating the rate of company compulsory liquidation in the UK via Bayesian inference and frequentist statistical methods.

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    In this paper, we investigate the rate of company compulsory liquidation (insolvency) (CCL) via Bayesian inference applied with the use of ‘OpenBUGS’ and ‘R’ software mediums. This study follows on from a previous ‘frequentist’ statistical based study of one of the authors and introduces the usefulness of Bayesian inference as the statistical tool. CCL occurs when a company creditor successfully petitions the courts for a winding up order. There are a finite number of variables that can affect the possibility of company creditors instigating CCL. The model in this study included those variables found to be statistically significant within the data range contained in the previous ‘frequentist’ study. We commence by presenting the model from the previous ‘frequentist’ study along with an analysis of the results of that study. We then introduce the concept of Bayesian inference to the study and apply the inference to the ‘frequentist’ model, and analyse the results of the new model. Finally, we then compare the two sets of findings and report our conclusions, and the implications for the modeling of insolvencies

    Coronary artery bypass grafting in non–dialysis-dependent mild-to-moderate renal dysfunction

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    AbstractObjectives: The effect of mild-to-moderate elevation of preoperative serum creatinine levels on morbidity and mortality from coronary artery bypass grafting has not been investigated in a large multivariable model incorporating preoperative and intraoperative variables. Our first objective was to ascertain the effect of a mild-to-moderate elevation in the preoperative serum creatinine level on the need for mechanical renal support; the duration of special care and total postoperative stay; the occurrence of infective, respiratory, and neurologic complications; and hospital mortality. Our second objective was to ascertain which patient variables contributed to an increase in the serum creatinine level in association with coronary artery bypass grafting. Methods: A total of 1427 patients who had no known pre-existing renal disease and who were undergoing first-time coronary artery bypass grafting with cardiopulmonary bypass were recruited for the study. Patients were divided, on the basis of preoperative serum creatinine level, into 3 groups as follows: creatinine level of less than 130 μmol · L–1; creatinine level of 130 to 149 μmol · L–1; and creatinine level of 150 μmol · L–1 or greater. A multivariable stepwise logistic regression analysis was used, and variables significant at the 5% level were included when developing the final multivariable models. Results: Multivariable analysis showed that elevation of the preoperative serum creatinine level to 130 μmol · L–1 or greater increased the likelihood of needing mechanical renal support postoperatively (P <.001), as well as the need for postoperative special care (P <.001) and total hospital stay (P <.001). In-hospital mortality was also significantly elevated as the preoperative creatinine level rose to 130 to 149 μmol · L–1 (P =.045) and to 150 μmol · L–1 or greater (P <.001). It was further observed that patients with preoperative serum creatinine levels of 130 to 149 μmol · L–1 (P =.02), patients with preoperative serum creatinine levels of 150 μmol · L–1 or greater (P =.001), hypertensive patients (P =.007), patients with angina of New York Heart Association class III or greater (P =.001), patients having a nonelective operation (P =.002), and patients having a prolonged cardiopulmonary bypass time (P =.008) had a significantly greater increase in the serum creatinine level as a result of coronary artery bypass grafting. Of particular note was the finding that the method of myocardial protection (cardioplegia or crossclamp fibrillation) did not significantly influence in-hospital mortality, need for mechanical renal support, or special care or total postoperative hospital stay. Conclusions: A mild elevation (130-149 μmol · L–1) in the preoperative serum creatinine level significantly increases the need for mechanical renal support, the duration of special care and total postoperative stay, and the in-hospital mortality. As the preoperative serum creatinine level increases further (≥150 μmol · L–1), this effect is more pronounced. No significant difference in outcome was observed between the use of cardioplegia or crossclamp fibrillation for myocardial protection. (J Thorac Cardiovasc Surg 2001;121:1083-9

    High-Resolution Infrared Spectroscopy of the Brown Dwarf Epsilon Indi Ba

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    We report on the analysis of high-resolution infrared spectra of the newly discovered brown dwarf Epsilon Indi Ba. This is the closest known brown dwarf to the solar system, with a distance of 3.626 pc. Spectra covering the ranges of 2.308-2.317 microns and 1.553-1.559 microns were observed at a spectral resolution of R=50,000 with the Phoenix spectrometer on the Gemini South telescope. The physical paramters of effective temperature and surface gravity are derived by comparison to model spectra calculated from atmospheres computed using unified cloudy models. An accurate projected rotational velocity is also derived.Comment: 9 pages, 3 figures. Astrophysical Journal Letters, in pres

    CRYOGENIC UPPER STAGE SYSTEM SAFETY

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    NASA s Exploration Initiative will require development of many new systems or systems of systems. One specific example is that safe, affordable, and reliable upper stage systems to place cargo and crew in stable low earth orbit are urgently required. In this paper, we examine the failure history of previous upper stages with liquid oxygen (LOX)/liquid hydrogen (LH2) propulsion systems. Launch data from 1964 until midyear 2005 are analyzed and presented. This data analysis covers upper stage systems from the Ariane, Centaur, H-IIA, Saturn, and Atlas in addition to other vehicles. Upper stage propulsion system elements have the highest impact on reliability. This paper discusses failure occurrence in all aspects of the operational phases (Le., initial burn, coast, restarts, and trends in failure rates over time). In an effort to understand the likelihood of future failures in flight, we present timelines of engine system failures relevant to initial flight histories. Some evidence suggests that propulsion system failures as a result of design problems occur shortly after initial development of the propulsion system; whereas failures because of manufacturing or assembly processing errors may occur during any phase of the system builds process, This paper also explores the detectability of historical failures. Observations from this review are used to ascertain the potential for increased upper stage reliability given investments in integrated system health management. Based on a clear understanding of the failure and success history of previous efforts by multiple space hardware development groups, the paper will investigate potential improvements that can be realized through application of system safety principles

    Derivation of a clinical decision guide in the diagnosis of cervical facet joint pain

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    Objective To derive a clinical decision guide (CDG) to identify patients best suited for cervical diagnostic facet joint blocks. Design Prospective cohort study. Setting Pain management center. Participants Consecutive patients with neck pain (N=125) referred to an interventional pain management center were approached to participate. Interventions Subjects underwent a standardized testing protocol, performed by a physiotherapist, prior to receiving diagnostic facet joint blocks. All subjects received the reference standard diagnostic facet joint block protocol, namely controlled medial branch blocks (MBBs). The physicians performing the MBBs were blinded to the local anesthetic used and findings of the clinical tests. Main Outcome Measures Multivariate regression analyses were performed in the derivation of the CDGs. Sensitivity, specificity, positive and negative likelihood ratios, and 95% confidence intervals (CIs) were calculated for the index tests and CDGs. Results A CDG involving the findings of the manual spinal examination (MSE), palpation for segmental tenderness (PST), and extension-rotation (ER) test demonstrated a specificity of 84% (95% CI, 77-90) and a positive likelihood ratio of 4.94 (95% CI, 2.8-8.2). Sensitivity of the PST and MSE were 94% (95% CI, 90-98) and 92% (95% CI, 88-97), respectively. Negative findings on the PST were associated with a negative likelihood ratio of.08 (95% CI,.03-.24). Conclusions MSE, PST, and ER may be useful tests in identifying patients suitable for diagnostic facet joint blocks. Further research is needed to validate the CDGs prior to their routine use in clinical practice

    The Northeast Water polynya as an atmospheric CO2 sink: a seasonal rectification hypothesis

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    During the multidisciplinary ‘NEW92’ cruise of the United States Coast Guard Cutter (USCGC) Polar Sea to the recurrent Northeast Water (NEW) Polynya (77–81°N, 6–17°W; July–August 1992), total dissolved inorganic carbon and total alkalinity in the water column were measured with high precision to determine the quantitative impact of biological processes on the regional air-sea flux of carbon. Biological processes depleted the total inorganic carbon of summer surface waters by up to 2 mol C m−2 or about 3%. On a regional basis this depletion correlated with depth-integrated values of chlorophyll a, particulate organic carbon, and the inorganic nitrogen deficit. Replacement of this carbon through exchange with the atmosphere was stalled owing to the low wind speeds during the month of the cruise, although model calculations indicate that the depletion could be replenished by a few weeks of strong winds before ice forms in the autumn. These measurements and observations allowed formulation of a new hypothesis whereby seasonally ice-covered regions like the NEW Polynya promote a unique biologically and physically mediated “rectification” of the typical (ice free, low latitude) seasonal cycle of air-sea CO2 flux. The resulting carbon sink is consistent with other productivity estimates and represents an export of biologically cycled carbon either to local sediments or offshore. If this scenario is representative of seasonally ice-covered Arctic shelves, then the rectification process could provide a small, negative feedback to excess atmospheric CO2

    COVID-19 Pneumothorax in the United Kingdom: a prospective observational study using the ISARIC WHO clinical characterisation protocol.

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    Population level data from 131 679 patients show that COVID-19 pneumothorax occurs in 0.97% of admitted patients, especially males and smokers, and is associated with increased mortality
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