Disposal of Phenolic Waters From a Producer Gas Plant

Phenolic waters are generated in a producer gas plant in India. Since harmful environmental effects can result even with low concentrations of phenol in water, its disposal poses a problem. Four options for disposal were considered. One of these options considered involves disposal in a earthen pond situated close to a river. In order to avoid river pollution by possible seepage of phenolic waste, geotechnical aspects have to be considered. For each option, cost analysis is performed. This paper d1scusses as to how the final disposal technique is decided taking into account all the relevant aspects of the problem

Interval Estimation for the Difference in Paired Areas under the ROC Curves in the Absence of a Gold Standard Test

Receiver operating characteristic (ROC) curves can be used to assess the accuracy of tests measured on ordinal or continuous scales. The most commonly used measure for the overall diagnostic accuracy of diagnostic tests is the area under the ROC curve (AUC). A gold standard test on the true disease status is required to estimate the AUC. However, a gold standard test may sometimes be too expensive or infeasible. Therefore, in many medical research studies, the true disease status of the subjects may remain unknown. Under the normality assumption on test results from each disease group of subjects, using the expectation-maximization (EM) algorithm in conjunction with a bootstrap method, we propose a maximum likelihood based procedure for construction of confidence intervals for the difference in paired areas under ROC curves in the absence of a gold standard test. Simulation results show that the proposed interval estimation procedure yields satisfactory coverage probabilities and interval lengths. The proposed method is illustrated with two examples

Serological Evidence of Subclinical Transmission of the 2009 Pandemic H1N1 Influenza Virus Outside of Mexico

Background: Relying on surveillance of clinical cases limits the ability to understand the full impact and severity of an epidemic, especially when subclinical cases are more likely to be present in the early stages. Little is known of the infection and transmissibility of the 2009 H1N1 pandemic influenza (pH1N1) virus outside of Mexico prior to clinical cases being reported, and of the knowledge pertaining to immunity and incidence of infection during April-June, which is essential for understanding the nature of viral transmissibility as well as for planning surveillance and intervention of future pandemics. Methodology/Principal Findings: Starting in the fall of 2008, 306 persons from households with schoolchildren in central Taiwan were followed sequentially and serum samples were taken in three sampling periods for haemagglutination inhibition (HI) assay. Age-specific incidence rates were calculated based on seroconversion of antibodies to the pH1N1 virus with an HI titre of 1: 40 or more during two periods: April-June and September-October in 2009. The earliest time period with HI titer greater than 40, as well as a four-fold increase of the neutralization titer, was during April 26-May 3. The incidence rates during the pre-epidemic phase (April-June) and the first wave (July-October) of the pandemic were 14.1% and 29.7%, respectively. The transmissibility of the pH1N1 virus during the early phase of the epidemic, as measured by the effective reproductive number R(0), was 1.16 (95% confidence interval (CI): 0.98-1.34). Conclusions: Approximately one in every ten persons was infected with the 2009 pH1N1 virus during the pre-epidemic phase in April-June. The lack of age-pattern in seropositivity is unexpected, perhaps highlighting the importance of children as asymptomatic transmitters of influenza in households. Although without virological confirmation, our data raise the question of whether there was substantial pH1N1 transmission in Taiwan before June, when clinical cases were first detected by the surveillance network

The generalized inference on the ratio of mean differences for fraction retention noninferiority hypothesis.

The fraction retention non-inferiority hypothesis is often measured for the ratio of the effects of a new treatment to those of the control in medical research. However, the fraction retention non-inferiority test that the new treatment maintains the efficacy of control can be affected by the nuisance parameters. Herein, a heuristic procedure for testing the fraction retention non-inferiority hypothesis is proposed based on the generalized p-value (GPV) under normality assumption and heteroskedasticity. Through the simulation study, it is demonstrated that, the performance of the GPV-based method not only adequately controls the type I error rate at the nominal level but also is uniformly more powerful than the ratio test, Rothmann's and Wang's tests, the comparable extant methods. Finally, we illustrate the proposed method by employing a real example

Generalized Inferences on Problems in Biostatistics

本研究主要探討廣義推論(generalized inference)在生物統計之應用。研究主要分成三個部份。體外溶離率試驗已被建議用來替代藥物生體相等性試驗來進行變化前後藥品的相似性之評估。研究的第一部份主要是利用廣義p值(generalized p-value)的概念，在體外溶離率試驗下進行變化前後藥品的相似性之評估。美國食品藥物管理局(FDA)已公告數個有關核准後藥品變化評估的準則。這些公告中所提出評估溶離率剖析曲線(dissolution profile)相似性的標準為根據溶解度平均差均方如相似因子f2，或溶解度平均差絕對值的平均如相似因子g1而訂定。由於相似因子f2與g1的分配複雜不易推導求得，故進行溶離率剖析曲線相似性的檢定就相對困難。因此我們嘗試透過廣義p值(generalized p-value)的概念來進行溶離率剖析曲線的相似性之評估，透過大型的模擬試驗在不同溶解度平均數差、變異數及藥品樣本數下，探討該統計方法之偏差、型I誤差與檢定力並與拔靴法(bootstrap method)的結果做比較。模擬結果發現，以相似因子f2與g1作為評估溶離率剖析曲線相似性的準則時，隨著藥品樣本數愈大，廣義p值與拔靴法的評估表現一樣好。最後透過一個實例以相似因子f2與g1作為評估溶離率剖析曲線相似性的準則時，針對廣義p值法與拔靴法作比較。受者操作特徵曲線(receiver operating characteristic curve)簡稱ROC曲線，是常用來評估診斷工具準確性的統計方法。在診斷試驗中，比較新診斷工具與現行標準診斷工具的準確性是一項重要的課題。當黃金標準試驗(gold standard test)存在時，一般常以ROC曲線下面積作為評估診斷工具準確性的指標。然而有些情形下，黃金標準試驗執行費用太昂貴或是黃金標準試驗無法取得。故研究的第二部份主要是討論在常態性假設下，當黃金標準試驗不存在時，利用EM演算法及拔靴法，提出以最大概似法(maximum likelihood method)為基礎的統計程序，針對成對(paired)ROC曲線下面積建立其信賴區間之研究。透過大規模的統計模擬研究可驗證，當黃金標準試驗不存在時，我們提出的區間估計能提供足夠的覆蓋機率(coverage probability)。此外我們亦利用廣義樞紐量(generalized pivotal quantity)來建立當黃金標準試驗不存在時成對ROC曲線下面積的廣義信賴區間(generalized confidence interval)。由統計模擬研究可驗證，當黃金標準試驗不存在時，成對ROC曲線下面積的廣義信賴區間亦能提供足夠的覆蓋機率。最後，利用提出之方法針對胰臟癌(pancreatic cancer)、動脈硬化症(atherosclerosis)等實際診斷資料進行分析。三部份利用廣義p值的概念，當變異數異質(heteroscedasticity)時，評估新處理(new treatment)在three-arm試驗中，的非劣性(non-inferiority)。透過模擬試驗，在不同變異數及樣本數組合下，探討提出統計方法之型I誤差與檢定力。一般而論，我們提出的方法之型I誤差均能接近宣稱的水準(nominal level)，其檢定力優於Fieller''s法與拔靴法。最後，利用提出之統計方法針對兩個實例進行資料分析。The main objective of this dissertation is to use generalized inference on biostatistics. There are three parts in this dissertation. In vitro dissolution testing has been suggested as a surrogate for assessment of bioequivalence between the test and reference formulations for postapproval changes. First is that we use the concept of generalized p-values (GPVs) to assessment of similarity between dissolution profiles. The often used criteria for assessment of dissolution similarity between general profiles are functions of average squared mean differences and absolute mean difference. Because of the complexity of the distributions of estimators of two functions, it is difficult to obtain a test to test the hypothesis of dissolution similarity. Therefore, in first study, the GPVs is applied to construct a test procedure to assess the similarity of dissolution profiles. Simulation results show that when the numbers of dosage units are large, the GPVs testing procedure yields satisfactory results for size and power with f2 and g1 criteria recommended by the U.S. Food and Drug Administration (FDA). Through this simulation study, with the same f2 and g1 criteria, the performance of empirical sizes and empirical power by using GPVs are as good as by using bootstrap method. The proposed method is illustrated with a real example.he receiver operating characteristic (ROC) curve is a popular statistical tool for the accuracy of diagnostic device. One of primary objectives in a diagnostic test evaluation study is to compare the diagnostic accuracy of the new diagnostic procedure with that of current standard procedure. The second part is that we construct confidence intervals for the difference in paired areas under ROC curves in the absence of a gold standard test. The ROC curves can be used to assess the accuracy of tests measured on ordinal or continuous scales. The most commonly used measure for the overall diagnostic accuracy of continuously valued diagnostic tests is the area under the ROC curve. To estimate such a measure, we require the existence of a gold standard test on the presence of disease status. However a gold standard test may sometimes be too expensive or infeasible to obtain. Therefore, in many medical research studies, the true disease status of the subjects may not be known or available. Under the normality assumption on the diagnostic test results from each group of subjects, based on the expectation-maximization (EM) algorithm in conjunction with a bootstrap method, we propose a maximum likelihood based procedure for construction of confidence intervals for the difference in paired areas under ROC curves in the absence of a gold standard test. In addition, we also propose to use the concept of generalized pivotal quantities (GPQs) to construct generalized confidence intervals (GCIs) for the difference in paired areas under ROC curves in the absence of a gold standard test. Simulation results show that the proposed interval estimation procedures yield satisfactory coverage probabilities and expected lengths. The proposed methods are illustrated with two data examples.he last part is that we propose a generalized inference on assessment non-inferiority of a new treatment in a three-arm trial in the presence of heteroscedasticity. In non-inferiority trials, the goal is to show how an experimental treatment is statistically and clinically not inferior to the active control. The three-arm clinical trial usually recommended for non-inferiority trials by the FDA. The three-arm trial consists of a placebo, reference, and an experimental treatment. In this study, under the normality assumption on the placebo, reference, and an experimental treatment, the GPVs is applied to facilitate non-inferiority tests in a three-arm design. In the situation of heterogeneous group variances, through a simulation study, the GPVs will adequately maintain the alpha level than Fieller''s method and bootstrap method. Simulation results also show that the performance of empirical power of GPVs method is as good as that of the Fieller''s method and the bootstrap method. Finally, the proposed method is illustrated with two data examples.Contents Introduction 1.1 Assessment of similarity between dissolution profiles 2.2 The paired areas under the ROC curves in the absence of a gold standard . 4.3 Assessment non-inferiority of a new treatment in a three-arm trial in theresence of heteroscedasticity . 6.4 Organization of the dissertation . 7 Preliminaries of Generalized Statistical Inference 8.1 Generalized p-values. 8.2 Generalized confidence intervals . 9 A Generalized Inference on Assessment of Similarity between Dissolutionrofiles 11.1 Criteria and Formulation of Hypothesis for Dissolution Profile Similarity . 12.1.1 Similarity criterion based on squared mean difference . 12.1.2 Similarity criterion based on absolute mean difference. 13.2 Generalized inference on similarity factor f2 and g1 14.3 Simulation Study and Results 18.3.1 Simulation study on empirical bias. 18.3.2 Simulation study on type I error rate 19.3.3 Simulation study on power . 23.4 Numerical Examples. 26.5 Conclusion and Final Remarks. 28 Interval Estimation by Using ML-Based Method for the Difference inaired Areas under the ROC Curves in the Absence of a Gold Standard 32.1 The Proposed ML-BasedMethod 33.1.1 EM algorithm . 34.1.2 Bootstrap method 36.2 Simulation Studies 37.2.1 Simulation study I 37.2.2 Simulation study II42.2.3 Simulation study III 42.3 Numerical Examples 45.3.1 The study of pancreatic cancer serum biomarkers 45.3.2 The study of accuracy of magnetic resonance angiography (MRA)eadings by two readers 46.4 Discussion and Final Remarks 47 Generalized Confidence Interval Estimation for the Difference in Pairedreas under the ROC Curves in the Absence of a Gold Standard 50.1 Generalized Confidence Interval Estimation 51.2 Simulation Studies 55.3 Numerical Examples 60.3.1 The study of pancreatic cancer serum biomarkers 60.3.2 The study of accuracy of magnetic resonance angiography (MRA)eadings by two readers61.4 Discussion and Final Remarks 62 A generalized inference on assessment non-inferiority of a new treatmentn a three-arm trial in the presence of heteroscedasticity 63.1 Introduction 63.2 Statistical Background and Non-inferiority Hypothesis 64.3 Generalized inference on the ratio of the differences inmeans 67.4 Simulation Study 70.4.1 Simulation study on type I error rate 71.4.2 Simulation study on power 84.5 Numerical Examples 88.5.1 A comparative study inmildly asthmatic patients88.5.2 Evaluation of themutagenicity example 89.6 Conclusion and Final Remarks 91 Future Research 92ibliography 95 Appendix A 102 Appendix B: The estimators in M-step 10

Sustainable Community Sanitation for a Rural Hospital in Haiti

sustainabilit

Community Based Pollution Prevention for Two Urban Cities—A Case Study

Pollution prevention is an approach for generating less waste using fewer toxic chemicals while conserving water and energy. Even though pollution prevention practices have been encouraged for over thirty years, many smaller businesses have not considered or adopted such techniques. This study examines the effect of a community-based approach designed to emphasize the benefits to the health and economic well-being of urban communities when source reduction practices are implemented by businesses in the community. Partnering with existing community groups in Newark and Jersey City, NJ, technical assistance was provided to small and medium-sized businesses under grant funding from Region 2 of the US Environmental Protection Agency. In this research, 32 small and medium-sized businesses were evaluated for source reduction opportunities and implementation plans were drawn up. After these businesses implemented operational changes, emission and cost savings were determined and reported back to respective small business owners as well as to the communities during community meetings designed to encourage additional participation. Based on 32 case studies, several measurable benefits were achieved, including the yearly saving of 932 pounds of hazardous waste, 3917 pounds of non-hazardous waste, 13.62 metric tons of carbon equivalent (MTCE) of greenhouse gases and $5335 USD. The initial findings suggest that community-based programs such as this can be beneficial but must be sustained over a period of time. One issue that was repeatedly observed, and is likely widely believed, is the concern of small business operators that cooperation with any group funded by a government program may lead to the assessment of fines or penalties for environmental violations. This concern limits the willingness of many smaller businesses to participate. The findings of this study suggest that a sustained community-based program may overcome that concern through demonstration of the benefit to the business and the community, and through credibility building achieved by regular community reporting and the absence of official intervention

Two-stage revision arthroplasty for Mycobacterium Tuberculosis periprosthetic joint infection: An outcome analysis.

BACKGROUND:Mycobacterium tuberculosis periprosthetic joint infection (TBPJI) is a rare complication of hip/knee joint arthroplasty. The outcomes of hip/knee TBPJI treatment are still unreported. The objective of this study was to investigate the outcomes of hip/knee TBPJI following treatment with two-stage exchange arthroplasty. MATERIALS AND METHODS:From 2003 to 2013, 11 patients with TBPJI (six hips and five knees) were treated with two-stage exchange arthroplasty at our institution. We collected and analyzed variables including demographic data, comorbidities, microbiological data, duration of symptoms, and types of antibiotic used in bone cement. RESULTS:At the most recent follow-up, the success rate of two-stage exchange arthroplasty was 63.3% (7 of 11). All five knee treatments resulted in infection eradication and successful prosthesis reimplantation. However, only two hip TBPJI treatments resulted in successful outcomes; two patients died and two experienced chronic infection. Overall, secondary bacterial infections were common in patients with TBPJI (5 of 11 cases, 45.5%). Streptomycin in bone cement increased the success rate (83.33% vs. 40%). CONCLUSION:More than one third of the patients treated with two-stage exchange arthroplasty for TBPJI showed infection relapse or uncontrolled infection. Streptomycin-loaded interim cement spacers appeared to help ensure successful treatment. Routine M. tuberculosis culture is recommended when treating TBPJI in areas of high tuberculosis prevalence