Supply chain contamination: An exploratory approach on the collateral effects of negative corporate events

The present work investigates the impact of negative events on supply chain partners. Through a contextualised discussion of the literature on supply chains and on the efficient market hypothesis, it is proposed that negative events negatively impact the market value of suppliers and customers. Following an exploratory approach, 307 companies (21 source companies, 158 suppliers and 128 customers) comprehending 20 cases of environmental disaster, corporate social irresponsibility, operational failure, corporate fraud and corruption were analysed. Results show that in 12 out of the 20 cases investigated supply chain partners indeed had their market value penalised, encompassing, to a greater or lesser degree, all five categories of cases considered. Yet, while both suppliers and customers absorbed the outcomes of negative events, suppliers seem to be at greater risk of sustaining such losses. Likewise, cases in which the source companies were also negatively affected seem to be slightly more prone to cause losses among suppliers and customers. In this sense, the concept of supply chain contamination is coined to address the observed outcomes. The study offers new insights into the applicability of the efficient market hypothesis and contributes to the assessment of the dissemination of negative events in supply chains, a theme that, despite its potential detrimental consequences for firms and stakeholders, has not yet been sufficiently treated in the Management literature.     

Risk-Based Assessment of Soil and Groundwater Quality in the Netherlands: Standards and Remediation Urgency

To assess soil and groundwater quality two generic (i.e. multifunctional) risk-based standards, Target and Intervention Value, have been developed, in the framework of the Dutch Soil Protection Act. These standards allow soil and groundwater to be classified as clean, slightly contaminated or seriously contaminated. The Target Value is based on potential risks to ecosystems, while the Intervention Value is based on potential risks to humans and ecosystems. In the case of serious soil contamination the site has, in principle, to be remediated, making it necessary to determine the remediation urgency on the basis of actual (i.e. site-specific) risks to humans and ecosystems and, besides, actual risks due to contaminant migration.     

The estimation of gross flows in the presence of measurement error using auxiliary variables

Classification error can lead to substantial biases in the estimation of gross flows from longitudinal data. We propose a method to adjust flow estimates for bias, based on fitting separate multinomial logistic models to the classification error probabilities and the true state transition probabilities using values of auxiliary variables. Our approach has the advantages that it does not require external information on misclassification rates, it permits the identification of factors that are related to misclassification and true transitions and it does not assume independence between classification errors at successive points in time. Constraining the prediction of the stocks to agree with the observed stocks protects against model misspecification. We apply the approach to data on women from the Panel Study of Income Dynamics with three categories of labour force status. The model fitted is shown to have interpretable coefficient estimates and to provide a good fit. Simulation results indicate good performance of the model in predicting the true flows and robustness against departures from the model postulated.     

Sensitivity of some posterior summaries when the prior is unimodal with specified quantiles

Prior information is modeled either by (1) a class of unimodal distributions with specified quantiles, or by (2) an ∈-contamination class with contaminations subject to unimodal and quantile restrictions. We show how the ranges of certain posterior summaries can be found. Using numerical examples, we compare the robustness behaviour under these classes, and assess the effect, in terms of robustness, of specifying a base prior.     

土壤污染防治立法的效果导向及其实现

从规范的内容、规制形式等方面分析,土壤污染防治专门立法应当坚持效果导向,要与调整土壤污染源的大气、水、固体废物、化学品等上游制度,以及食品、人居安全等下游制度实现效力对接与协同,并超越当前效果乏力的实施模式。未来立法的效果导向实现需要围绕“土壤质量保持”这个核心,坚持在红线思维指导下确立国家、经营者和公众的权利（力）义务,区分底土与表层土壤的权利属性,创新我国土地权利结构。     

不可压缩地下水水质污染模型广义解的唯一性

不可压缩地下水水质污染问题的数学模型由一类非线性抛物－椭圆耦合方程组的初边值问题描述,本文用积分估计法证明这一模型广义解的唯一性。     

Optimal Tests for No Contamination in Reliability Models

Inferences on mixtures of probability distributions, in general,and of life distributions, in particular, are receiving considerableimportance in recent years. The likelihood ratio procedure oftesting for the null hypothesis of no contamination is oftenvery cumbersome and lacks its usual asymptotic properties. Recently,SenGupta (1991) has introduced the notion of an `L-optimal' testfor such testing problems. The idea is to recast the originalseveral parametric hypotheses representation of the null hypothesisin terms of only a single hypothesis involving an appropriatelychosen parametric function. This approach is shown to be bothmathematically elegant and operationally simple for a quite generalclass of mixture distributions which contains, in particular,all mixtures of the one-parameter exponential family and alsoa very rich subclass of mixtures useful in life-testing and reliabilityanalysis. It is also illustrated through two examples—onebased on real-life data and the other on a simulated sample.     

Structured expert elicitation about Listeria monocytogenes cross-contamination in the environment of retail deli operations in the United States

Listeria monocytogenes is among the foodborne pathogens with the highest death toll in the United States. Ready‐to‐eat foods contaminated at retail are an important source of infection. Environmental sites in retail deli operations can be contaminated. However, commonly contaminated sites are unlikely to come into direct contact with food and the public health relevance of environmental contamination has remained unclear. To identify environmental sites that may pose a considerable cross‐contamination risk, to elucidate potential transmission pathways, and to identify knowledge gaps, we performed a structured expert elicitation of 41 experts from state regulatory agencies and the food retail industry with practical experience in retail deli operations. Following the “Delphi” method, the elicitation was performed in three consecutive steps: questionnaire, review and discussion of results, second questionnaire. Hands and gloves were identified as important potential contamination sources. However, bacterial transfers to and from hands or gloves represented a major data gap. Experts agreed about transfer probabilities from cutting boards, scales, deli cases, and deli preparation sinks to product, and about transfer probabilities from floor drains, walk‐in cooler floors, and knife racks to food contact surfaces. Comparison of experts' opinions to observational data revealed a tendency among experts with certain demographic characteristics and professional opinions to overestimate prevalence. Experts’ votes clearly clustered into separate groups not defined by place of employment, even though industry experts may have been somewhat overrepresented in one cluster. Overall, our study demonstrates the value and caveats of expert elicitation to identify data gaps and prioritize research efforts.     

Reducing Drinking Water Supply Chemical Contamination: Risks from Underground Storage Tanks

Drinking water supplies are at risk of contamination from a variety of physical, chemical, and biological sources. Ranked among these threats are hazardous material releases from leaking or improperly managed underground storage tanks located at municipal, commercial, and industrial facilities. To reduce human health and environmental risks associated with the subsurface storage of hazardous materials, government agencies have taken a variety of legislative and regulatory actions—which date back more than 25 years and include the establishment of rigorous equipment/technology/operational requirements and facility‐by‐facility inspection and enforcement programs. Given a history of more than 470,000 underground storage tank releases nationwide, the U.S. Environmental Protection Agency continues to report that 7,300 new leaks were found in federal fiscal year 2008, while nearly 103,000 old leaks remain to be cleaned up. In this article, we report on an alternate evidence‐based intervention approach for reducing potential releases from the storage of petroleum products (gasoline, diesel, kerosene, heating/fuel oil, and waste oil) in underground tanks at commercial facilities located in Rhode Island. The objective of this study was to evaluate whether a new regulatory model can be used as a cost‐effective alternative to traditional facility‐by‐facility inspection and enforcement programs for underground storage tanks. We conclude that the alternative model, using an emphasis on technical assistance tools, can produce measurable improvements in compliance performance, is a cost‐effective adjunct to traditional facility‐by‐facility inspection and enforcement programs, and has the potential to allow regulatory agencies to decrease their frequency of inspections among low risk facilities without sacrificing compliance performance or increasing public health risks.