90 research outputs found

    Quantifying Performance Bias in Label Fusion

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    Classification systems are employed to remotely assess whether an element of interest falls into a target class or non-target class. These systems have uses in fields as far ranging as biostatistics to search engine keyword analysis. The performance of the system is often summarized as a trade-off between the proportions of elements correctly labeled as target plotted against the number of elements incorrectly labeled as target. These are empirical estimates of the true positive and false positive rates. These rates are often plotted to create a receiver operating characteristic (ROC) curve that acts as a visual tool to assess classification system performance. The research contained in this thesis focuses on the label fusion technique and the bias that can occur when using incorrect assumptions regarding the partitioning of the event set. This partitioning may be defined in terms of what will be called within and across label fusion. The major goals of this work are the formulaic development and quantification of performance bias between different types of across and within label fusion and analysis of the effects of individual classification system performance, correlation, and target environment on the magnitude of bias between these two types of label fusion

    Receiver Operating Characteristic Analysis for Detecting Explosives-related Threats

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    The Department of Homeland Security (DHS) and the Transportation Security Administration (TSA) are interested in developing a standardized testing procedure for determining the performance of candidate detection systems. This document outlines a potential method for judging detection system performance as well as determining if combining the information from a legacy system with a new system can signiÃÂÃÂÃÂÃÂcantly improve performance. In this document, performance corresponds to the Neyman-Pearson criterion applied to the Receiver Operating Characteristic (ROC) curves of the detection systems in question. A simulation was developed to investigate how the amount of data provided by the vendor in the form of the ROC curve eÃÂÃÂÃÂäects the performance of the combined detection system. Furthermore, the simulation also takes into account the potential eÃÂÃÂÃÂäects of correlation and how this information can also impact the performance of the combined system

    Self-reported sleep disturbances in renal transplant recipients

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    Abstract Background: Poor sleep quality (SQ) and daytime sleepiness (DS) are common in renal transplant (RTx) recipients; however, related data are rare. This study describes the prevalence and frequency of self-reported sleep disturbances in RTx recipients. Methods: This cross-sectional study included 249 RTx recipients transplanted at three Swiss transplant centers. All had reported poor SQ and / or DS in a previous study. With the Survey of Sleep (SOS) self-report questionnaire, we screened for sleep and health habits, sleep history, main sleep problems and sleep-related disturbances. To determine a basis for preliminary sleep diagnoses according to the International Classification of Sleep Disorders (ICSD), 164 subjects were interviewed (48 in person, 116 via telephone and 85 refused). Descriptive statistics were used to analyze the data and to determine the frequencies and prevalences of specific sleep disorders. Results: The sample had a mean age of 59.1 ± 11.6 years (60.2% male); mean time since Tx was 11.1 ± 7.0 years. The most frequent sleep problem was difficulty staying asleep (49.4%), followed by problems falling asleep (32.1%). The most prevalent sleep disturbance was the need to urinate (62.9%), and 27% reported reduced daytime functionality. Interview data showed that most suffered from the first ICSD category: insomnias

    Immunogenicity of High-Dose vs. MF59-adjuvanted vs. Standard Influenza Vaccine in Solid Organ Transplant Recipients: The STOP-FLU trial.

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    BACKGROUND The immunogenicity of the standard influenza vaccine is reduced in solid-organ transplant (SOT) recipients, so that new vaccination strategies are needed in this population. METHODS Adult SOT recipients from nine transplant clinics in Switzerland and Spain were enrolled if they were >3 months after transplantation. High, with stratification by organ and time from transplant. The primary outcome was vaccine response rate, defined as a ≥4-fold increase of hemagglutination-inhibition titers to at least one vaccine strain at 28 days post-vaccination. Secondary outcomes included PCR-confirmed influenza and vaccine reactogenicity. RESULTS 619 patients were randomized, 616 received the assigned vaccines, and 598 had serum available for analysis of the primary endpoint (standard, n=198; MF59-adjuvanted, n=205; high-dose, n=195 patients). Vaccine response rates were 42% (84/198) in the standard vaccine group, 60% (122/205) in the MF59-adjuvanted vaccine group, and 66% (129/195) in the high-dose vaccine group (difference in intervention vaccines vs. standard vaccine, 0.20 [97.5% CI 0.12-1]; p<0.001; difference in high-dose vs. standard vaccine, 0.24 [95% CI 0.16-1]; p<0.001; difference in MF59-adjuvanted vs. standard vaccine, 0.17 [97.5% CI 0.08-1]; p<0.001). Influenza occurred in 6% the standard, 5% in the MF59-adjuvanted, and 7% in the high-dose vaccine groups. Vaccine-related adverse events occurred more frequently in the intervention vaccine groups, but most of the events were mild. CONCLUSIONS In SOT recipients, use of an MF59-adjuvanted or a high-dose influenza vaccine was safe and resulted in a higher vaccine response rate. TRIAL REGISTRATION Clinicaltrials.gov NCT03699839

    Efficacy of standard and low dose hydrochlorothiazide in the recurrence prevention of calcium nephrolithiasis (NOSTONE trial): protocol for a randomized double-blind placebo-controlled trial.

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    Nephrolithiasis is a global healthcare problem with a current lifetime risk of 18.8% in men and 9.4% in women. Given the high cost of medical treatments and surgical interventions as well as the morbidity related to symptomatic stone disease, medical prophylaxis for stone recurrence is an attractive approach. Thiazide diuretics have been the cornerstone of pharmacologic metaphylaxis for more than 40 years. However, evidence for benefits and harms of thiazides in the prevention of calcium containing kidney stones in general remains unclear. In addition, the efficacy of the currently employed low dose thiazide regimens to prevent stone recurrence is not known. The NOSTONE trial is an investigator-initiated 3-year prospective, multicenter, double-blind, placebo-controlled trial to assess the efficacy of standard and low dose hydrochlorothiazide treatment in the recurrence prevention of calcium containing kidney stones. We plan to include 416 adult (≥ 18 years) patients with recurrent (≥ 2 stone episodes in the last 10 years) calcium containing kidney stones (containing ≥50% of calcium oxalate, calcium phosphate or a mixture of both). Patients will be randomly allocated to 50 mg or 25 mg or 12.5 mg hydrochlorothiazide or placebo. The primary outcome will be incidence of stone recurrence (a composite of symptomatic or radiologic recurrence). Secondary outcomes will be individual components of the composite primary outcome, safety and tolerability of hydrochlorothiazide treatment, changes in urinary biochemistry elicited by hydrochlorothiazide treatment and impact of baseline disease severity, biochemical abnormalities and stone composition on treatment response. The NOSTONE study will provide long-sought information on the efficacy of hydrochlorothiazide in the recurrence prevention of calcium containing kidney stones. Strengths of the study include the randomized, double-blind and placebo-controlled design, the large amount of patients studied, the employment of high sensitivity and high specificity imaging and the exclusive public funding support. ClinicalTrials.gov, NCT03057431 . Registered on February 20 2017

    “Finanzkonzerne: Welche Werte schaffen Zentralen?” with , Die Bank, No. 1, January 2006, pp.48 – 53.

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    Konzernzentralen müssen als Steuerungs-, Service- und Controllingeinheiten für die operativen Geschäftseinheiten Mehrwert generieren. Was in der Theorie so simpel klingt, bereitet in der Praxis regelmäßig Probleme

    Knowledge Management

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    This article links knowledge management to competitive advantage

    The Concept of Foresight in Times of Uncertainty and Ambiguity

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    This paper deductively explores alternative foresight processes and illustrates them by the description of the innovation process of the small tourist village St. Moritz
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