bluuebunny/crossref_metadata_2025 huggingface dataset:
Winners and Losers in a Major Price War
Authors: Van Heerde Harald J. , Gijsbrechts Els , Pauwels Koen
Published: September 2008

Although retail price wars have received much business press and some research attention, it is unclear how they affect consumer purchase behavior. This article studies an unprecedented price war in Dutch grocery retailing that started in fall 2003, initiated by the market leader to halt its sliding market share. The authors investigate the short- and long-term effects of the price war on store visits, on spending, and on the sensitivity of these decisions to weekly prices and price image. They use a unique data set with consumer hand-scan and perceptual data for a national panel of 1821 households, covering two years before and two years after the price war started. Although the price war initially entailed more shopping around and increased spending, spending per visit ultimately dropped because consumers redistributed their purchases across stores. The price war made consumers more sensitive to weekly prices and price image, which helped both the chain that showed an improvement in price image (the price war initiator) and the chains that already had a favorable price image (hard discounters). The price war initiator managed to halt the slide in its market share, and its stock price improved. The losers were the rival mid-level and high-end chains. Unlike the initiator, their price image did not improve, and they suffered from increased price image sensitivity. The authors provide managerial implications for firms that are (or about to be) involved in a price war.
Interorganizational Relationships and Bidding Behavior in Industrial Online Reverse Auctions
Authors: Jap Sandy D. , Haruvy Ernan
Published: September 2008

The authors model (1) the impact of the supplier's relationship propensity before the auction on the supplier's bidding aggressiveness in the auction (in terms of the number of bids it submits, the rate at which the bids are submitted, and the price concessions offered) and (2) the impact of bidding behaviors in the auction on the buyer–supplier relationship after auction through longitudinal survey data from 12 online reverse auctions across various product categories. The results suggest that incumbency, many bidders, and a willingness to make specific investments lead to less aggressive bidding, whereas the total number of bids from competing suppliers increases aggressiveness. In turn, aggressive bidding behavior reduces suppliers' disposition toward developing a relationship with the buyer and sours incumbent satisfaction with the relationship. Finally, auctions that are longer in duration can improve the relationship but may risk bidding competition. Collectively, the results suggest that pricing and relationships are intertwined and traded off against each other in complex ways and that the auction does not operate in isolation of key organizational variables.
Eliciting Preference for Complex Products: A Web-Based Upgrading Method
Authors: Park Young-Hoon , Ding Min , Rao Vithala R.
Published: September 2008

The authors propose a new incentive-aligned upgrading method for eliciting attribute preferences in complex products, which combines the merits of a self-explicated approach and conjoint analysis. The upgrading method first endows a participant with a product profile and then allows him or her to upgrade it, one attribute at a time, to a more desirable product configuration. During the process, the participant states his or her willingness to pay for each potential upgrade he or she is interested in, and a BDM (Becker–DeGroot–Marschak) procedure ensures that it is in the best interest of the participant to state truthfully his or her willingness to pay. Each participant receives the upgraded product at the end of the study. The authors empirically implement this procedure in a Web-based study with digital cameras. This procedure significantly improves predictive performance over the benchmark (self-explicated) approach.
To Innovate or Imitate? Entry Strategy and the Role of Market Research
Authors: Ofek Elie , Turut Ozge
Published: September 2008

A firm planning market entry can attempt to develop a product that is either similar to the incumbent's existing offering (imitation) or entirely novel (innovation). The authors establish that when the incumbent is more aggressive in research and development (R&D), this negatively affects the entrant's marginal return on R&D. Thus, if greater profits produce a strong (weak) desire for the incumbent to increase its R&D level, the entrant will respond by sharply decreasing (increasing) its R&D level. As a result, the incumbent's likelihood of retaining the lead position will exhibit an inverse U-shaped pattern as a function of monopoly and duopoly profits. The authors then examine the impact of uncertainty about the rewards from new products and allow firms to conduct market research to resolve the uncertainty. They characterize the conditions for the entrant's innovation versus imitation decision to reveal information about future rewards to the incumbent. When duopoly profits are uncertain and can be either high (upside potential) or low (downside potential), the entry strategy will be revealing if the upside potential is attractive enough relative to monopoly profits. In contrast, when innovation has uncertain commercial potential (i.e., either valued or not valued by consumers), the entry strategy will be revealing if duopoly profits are unattractive relative to monopoly profits. In these cases, the entrant's innovation–imitation decision is driven by market research; this allows the incumbent to forgo market research and infer the true state of demand from the type of entry strategy it observes.
An Integrated Model of Discrete Choice and Response Time
Authors: Otter Thomas , Allenby Greg M. , Van Zandt Trish
Published: September 2008

Computer and Web-based interviewing tools have made response times ubiquitous in marketing research. Practitioners use these data as an indicator of data quality, and academics use them as an indicator of latent processes related to memory, attributes, and decision making. The authors investigate a Poisson race model with choice and response times as dependent variables. The model facilitates inference about respondents' preferences for choice alternatives, their diligence in providing responses, and the accessibility of attitudes and the speed of thinking. Thus, the model distinguishes between respondents who are quick to think and those who are quick to react but do so without much thought. Empirically, the authors find support for the endogenous nature of response times and demonstrate that models that treat response times as exogenous variables may result in misleading inferences.
Split Questionnaire Design for Massive Surveys
Authors: Adigüzel Feray , Wedel Michel
Published: September 2008

Companies are conducting more and longer surveys than ever before. Massive questionnaires are pervasive in marketing practice. As an alternative to the heuristic methods that are currently used to split questionnaires, this study develops a methodology to design the split questionnaire in a way that minimizes information loss. Using estimates from a first wave or pilot study, the authors apply the modified Fedorov algorithm using the Kullback–Leibler distance as a design criterion to find the optimal splits. Their design criterion is based on a general mixed data model that accommodates continuous, rank-ordered, and discrete measurement scales. The optimal construction of the split questionnaire design is easy and fast. The authors use Markov chain Monte Carlo procedures to impute missing values that result from the design. They generate split questionnaire designs by selecting either entire blocks of questions (between-block design) or sets of questions in each block (within-block design). They compare the efficiency of split questionnaires generated with the proposed method with multiple matrix sampling designs, incomplete block designs, and a heuristic procedure, using synthetic and empirical Web survey data. The authors illustrate in a field study that as a result of reduced respondent burden, the quality of data using split questionnaire designs improves.
Constitutional Design and the Political Salience of “Community” Identity in Afghanistan: Prospects for the Emergence of Ethnic Conflicts in the Post-Taliban Era
Authors: Adeney Katharine
Published: September 2008

After the defeat of the Taliban, Afghanistan entered a period of constitutional flux. The 2004 Constitution rejected formal ethnic representation in state institutions. This Constitution, therefore, provides no defense against perceived or actual domination of the state by any one particular ethnic community. This could lead to increased ethnic resentment and conflicts.
Path Toward Democracy in South Korea: Social Capital and Democracy Embedded in the Citizens
Authors: Lee Jaechul
Published: September 2008

This study examines whether social capital promotes democratic citizenship. It reveals that the structural component of social capital motivates the Korean masses to participate in the political process and to embrace the norms of democratic behavior, while its cultural component encourages them to appreciate the virtues of democracy.
Security Community and Southeast Asia: Australia, the U.S., and ASEAN's Counter-Terror Strategy
Authors: Chau Andrew
Published: September 2008

This article evaluates the notion of an ASEAN Security Community. ASEAN's community building initiative is examined in the context of regional, sub-regional, and national policy strategies to address a shared regional threat of transnational terrorism. The article examines under which circumstances constructivist norms and institutions generate denser networks of cooperation.
Leadership Changes at the 10th Congress of the Vietnamese Communist Party
Authors: Koh David
Published: September 2008

This paper argues that while there was a large leadership turnover at the 10th Vietnamese Communist Party Congress in April 2006, the wait continues for younger leaders to emerge. The congress showed increased intraparty democracy. The willingness to go beyond regional distribution of power in the selection of top leaders was remarkable.
Production of donor-derived sperm after spermatogonial stem cell transplantation in the dog
Authors: Kim Yeunhee , Turner Danielle , Nelson Jacquelyn , Dobrinski Ina , McEntee Margaret , Travis Alexander J
Published: September 2008

Spermatogonial stem cell transplantation (SSCT) offers unique approaches to investigate SSC and to manipulate the male germline. We report here the first successful performance of this technique in the dog, which is an important model of human diseases. First, we investigated an irradiation protocol to deplete endogenous male germ cells in recipient testes. Histologic examination confirmed >95% depletion of endogenous spermatogenesis, but retention of normal testis architecture. Then, 5-month-old recipient dogs (n=5) were focally irradiated on their testes prior to transplantation with mixed seminiferous tubule cells (fresh (n=2) or after 2 weeks of culture (n=3)). The dogs receiving cultured cells showed an immediate allergic response, which subsided quickly with palliative treatment. No such response was seen in the dogs receiving fresh cells, for which a different injection medium was used. Twelve months post-injection recipients were castrated and sperm was collected from epididymides. We performed microsatellite analysis comparing DNA from the epididymal sperm with genomic DNA from both the recipients and the donors. We used six markers to demonstrate the presence of donor alleles in the sperm from one recipient of fresh mixed tubule cells. No evidence of donor alleles was detected in sperm from the other recipients. Using quantitative PCR based on single nucleotide polymorphisms (SNPs), about 19.5% of sperm were shown to be donor derived in the recipient. Our results demonstrate the first successful completion of SSCT in the dog, an important step toward transgenesis through the male germline in this valuable biomedical model.
Evidence that the effect of angiotensin II on bovine oocyte nuclear maturation is mediated by prostaglandins E2 and F2α
Authors: Barreta Marcos H , Oliveira João Francisco C , Ferreira Rogério , Antoniazzi Alfredo Q , Gasperin Bernardo G , Sandri Luciano R , Gonçalves Paulo Bayard D
Published: September 2008

Angiotensin II (AngII) prevents the inhibitory effect of follicular cells on oocyte maturation, but its involvement in LH-induced meiotic resumption remains unknown. The aim of this study was to assess the involvement of AngII in LH-induced meiotic resumption and of prostaglandins (PGs) in the action of AngII. In the experiment I, seven cows were superovulated, intrafollicularly injected with 10 μM saralasin (a competitive AngII antagonist) or saline when the follicles reached a diameter larger than 12 mm, and challenged with a GnRH agonist to induce an LH surge. Fifteen hours after GnRH, the animals were ovariectomized and the oocytes were recovered to determine the stage of meiosis. The oocytes from follicles that received saline were in germinal vesicle (GV) breakdown (30.8%) or metaphase I (MI; 69.2%) stage while those that received saralasin were in the GV stage (100%; P<0.001) 15 h after GnRH agonist. In another experiment, oocytes were co-cultured with follicular hemisections for 15 h to determine whether PGs mediate the effect of AngII on meiotic resumption. Indomethacin (10 μM) inhibited AngII-induced meiotic resumption (13.4 vs 77.5% MI without indomethacin; P<0.001). Furthermore, the GV oocytes progressed to MI at a similar rate when PGE2, PGF2α or AngII was present in the co-culture system with follicular cells (PGE2 77.4%, PGF2α 70.0%, and AngII 75.0% MI). In conclusion, our results provide strong evidence that AngII mediates the resumption of meiosis induced by an LH surge in bovine oocytes and that this event is dependent on PGE2 or PGF2α produced by follicular cells.
Improvement of sensitivity to tamoxifen in estrogen receptor-positive and Herceptin-resistant breast cancer cells
Authors: Chen Bin , Wang Yuanzhong , Kane Susan E , Chen Shiuan
Published: September 2008

ERBB2 overexpression in estrogen receptor (ER)-positive breast cancer cells such as BT474 (BT) cells has been found to confer resistance to tamoxifen, and suppression of ERBB2 improves the antiproliferative effects of tamoxifen. In this study, the responsiveness to tamoxifen in the BT/HerR, Herceptin-resistant BT cell lines established through constant Herceptin exposure, was evaluated. Compared with BT cells, improvement of sensitivity to tamoxifen in BT/HerR was demonstrated by ER functional analysis and cell proliferation assay. Tamoxifen in the resistant cell line was found to inhibit 17β-estradiol-stimulating estrogen-responsive gene pS2 expression more effectively than in BT cells in real-time PCR assay. Western blot analysis showed that cross-phosphorylation between ER and downstream components of ERBB2 was attenuated in BT/HerR cells. ER redistribution from cytoplasm to nucleus could be found in these cells through immunofluorescence and confocal studies, and importantly, chromatin immunoprecipitation studies demonstrated that tamoxifen induced occupancy of the pS2 promoter by ER and nuclear receptor corepressor (NCOR1) instead of coactivator NCOA3 in these cells. Finally, combination of tamoxifen and Herceptin was found to improve the sensitivity of BT/HerR cells to Herceptin. Our results suggest that the ER genomic pathway in the ER-positive and Herceptin-resistant breast cancer cells may be reactivated, allowing tamoxifen therapy to be effective again, and a combination of tamoxifen and Herceptin can be a potential therapeutic strategy for ER-positive and Herceptin-resistant human breast cancer.
Irregular flat slabs designed according to the structural membrane approach
Authors: Baskaran K.
Published: September 2008

In the construction industry, the need for flat slabs supported on columns in an irregular layout is rising. Design methods validated by experimental evidence for flat slabs supported on non-rectangular grid are, however, scarce. To fill this vacuum, two irregular flat slabs were tested at Nanyang Technological University. Those slabs, however, failed at almost twice the design ultimate load, showing the need for more work. In this paper, existing design methods based on lower bound approach are reviewed. Gurley's bimoment concepts are used to check the validity of zero twisting assumption in some of these methods. Also, experimental details of the nine flat slab panels, supported on non-rectangular grid, designed using the structural membrane approach and tested at Cambridge University Engineering Department are provided. Based on the observations, some suggestions are made for practical application of the structural membrane approach to design flat slabs on non-rectangular column grid.
Accounting for biaxial bending in yield-line analysis of reinforced concrete slabs
Authors: Denton S. , Morley C.
Published: September 2008

Yield-line analysis is conventionally undertaken using collapse mechanisms that comprise rigid regions that intersect at yield lines, which behave in uniaxial bending only. It is well established that the flexural capacity of reinforced concrete (RC) slabs subjected to biaxial bending can be less than that when they are subjected to uniaxial bending. Concerns must therefore result regarding whether the inability of conventional yield-line mechanisms to model regions of biaxial bending could lead to significantly unsafe (upper bound) results. A simple method is presented to enable zones of biaxial bending to be taken into account in yield-line analysis. In this method ‘wide’ yield-line mechanisms are used which comprise rigid regions that are connected by ‘yield lines’ of finite and constant width and with uniform finite curvature over their area. Two examples of the method are presented. From the results, it appears unlikely that the reduced flexural capacity of RC slabs in biaxial bending will have a highly significant effect on their overall capacity in many cases. Perhaps of greater significance is the variation in ductility observed for different bending cases.
The effect of acute fenitrothion exposure on a variety of physiological indices, including avian aerobic metabolism during exercise and cold exposure
Authors: Fildes Karen , Astheimer Lee B. , Buttemer William A.
Published: September 2008

The effect of fenitrothion exposure on birds was examined by measuring aerobic metabolism, blood hemoglobin content, plasma cholinesterases, and body weight for up to 21 d postdose. Peak metabolic rate was measured in a flight chamber in three-dose groups of house sparrows (Passer domesticus; 100 mg/kg = high, 60 mg/kg = medium, 30 mg/kg = low) and one-dose groups of zebra finches (Taeniopygia guttata; 3 mg/kg) and king quails (Coturnix chinensis; 26 mg/kg). Aerobic metabolism was measured during 1 h of exposure to subfreezing thermal conditions in low-dose house sparrows and king quails (26 mg/kg). Fenitrothion had no effect on metabolic rate during cold exposure or on blood hemoglobin at any time. By contrast, aerobic performance during exercise in sparrows was reduced by 58% (high), 18% (medium), and 20% (low), respectively, 2 d postdose. House sparrows (high) had the longest recovery period for peak metabolic rate (21 d) and plasma cholinesterase activity (14 d). House sparrows (high) and treated king quails had significantly lower myoglobin at 48 h postdose, whereas myoglobin was invariant in zebra finches and house sparrows (medium and low). Cholinesterase was maximally inhibited at 6 h postdose, and had recovered within 24 h, in house sparrows (low), king quails, and zebra finches. Exercise peak metabolic rate in zebra finches and king quails was reduced by 23% at 2 d and 3 d, respectively, despite these birds being asymptomatic in both behavior and plasma cholinesterase activities.
Research Joint Ventures, Optimal Licensing, and the R&D Subsidy Policy
Authors: Fan Cuihong , Wolfstetter Elmar G
Published: September 2008

We reconsider the justifications of the R&D subsidies of Spencer and Brander (1983), by allowing firms to form a research joint venture (RJV) and license innovations. If governments offer unconditional subsidies, an RJV is formed and the strategic benefits of R&D subsidies vanish. Nevertheless, governments subsidize their domestic firms to enhance their bargaining position in the joint venture subgame. If governments offer subsidies conditional on forming resp. not forming an RJV, the game has multiple equilibria: one that restores the Spencer and Brander result, and another in which governments induce the formation of an RJV by a combination of conditional taxes and subsidies.
First Evidence of Genetic Association Between AKT2 and Polycystic Ovary Syndrome
Authors: Goodarzi Mark O. , Jones Michelle R. , Chen Yii-Der I. , Azziz Ricardo
Published: September 2008

OBJECTIVE—Insulin resistance has been reported in up to 70% of women with polycystic ovary syndrome (PCOS). Physiologic and genetic data currently implicate post–insulin receptor signaling defects in substrates such as glycogen synthase kinase 3β (GSK3β). The AKT2 gene was chosen as a candidate for PCOS because its product affects glucose metabolism and mitogenic signaling, interacts with GSK3β, and mediates cell survival in the ovary.

RESEARCH DESIGN AND METHODS—Subjects were recruited from the reproductive endocrinology clinic at the University of Alabama at Birmingham, and control subjects were recruited from the surrounding community; 287 white women with PCOS and 187 white control subjects were genotyped for four single nucleotide polymorphisms (SNPs) in AKT2. Genotyping took place at Cedars-Sinai Medical Center in Los Angeles. SNPs and haplotypes were tested for association with PCOS risk and phenotypic markers of PCOS.

RESULTS—Minor allele carriers of SNPs rs3730051 and rs8100018 had increased odds of PCOS (odds ratio [OR] 2.2, P = 0.004, and 2.4, P = 0.001, respectively). The haplotype T-G-C-T was significantly associated with PCOS (OR 2.0, P = 0.01). Carriers of the risk haplotypes for both AKT2 and GSK3B had a further increased odds of PCOS (OR 3.1, P = 0.005).

CONCLUSIONS—These data suggest that polymorphisms in two components of the insulin signaling pathway, AKT2 and GSK3B, are associated with PCOS. The presence of multiple lesions in a single pathway may confer increased risk.
Impact of White-Coat Hypertension on Microvascular Complications in Type 2 Diabetes
Authors: Kramer Caroline K. , Leitão Cristiane B. , Canani Luís H. , Gross Jorge L.
Published: September 2008

OBJECTIVE—The purpose of this study was to determine the impact of white-coat hypertension (WCH) on microvascular complications in type 2 diabetes.

RESEARCH DESIGN AND METHODS—A cross-sectional study was conducted in normotensive patients and patients with WCH selected from a cohort of 319 type 2 diabetic patients. Normotension was defined by office blood pressure <140/90 mmHg and daytime blood pressure <135/85 mmHg on ambulatory blood pressure monitoring (ABPM). WCH was defined as office blood pressure ≥140/90 mmHg and daytime blood pressure <135/85 mmHg on ABPM. Subjects were evaluated for diabetic nephropathy (24-h urinary albumin excretion rate) and diabetic retinopathy (classified according to the Global Diabetic Retinopathy Group).

RESULTS—Forty-six type 2 diabetic patients had WCH (14.4%; mean age 56.6 years; 45.3% men) and 117 had normotension (36.6%; mean age 55.8 years; 37.5% men). These groups did not differ in clinical and main laboratory characteristics. Systolic ABPM (24-h: 124.7 ± 6.7 vs. 121.0 ± 8.5 mmHg, P = 0.01 and daytime: 126.6 ± 7.2 vs. 123.2 ± 8.2 mmHg, P = 0.01) and blood pressure loads were higher in subjects with WCH than in the normotensive subjects. WCH was associated with an increased risk for macroalbuminuria (odds ratio 4.9 [95% CI 1.3–18.7], P = 0.01). On multivariate analysis models, WCH was associated with macroalbuminuria (2.0 [1.3–3.2], P = 0.02) and increased the risk for both nonproliferative and proliferative diabetic retinopathy (2.7 [1.2–6.6], P = 0.02 for any degree of diabetic retinopathy) after adjustments for confounding factors.

CONCLUSIONS—Type 2 diabetic patients with WCH have an increased risk for diabetic retinopathy and diabetic nephropathy. Therefore, WCH should not be considered a harmless condition, and treatment should be considered.
Microsphere Surface Protein Determination Using Flow Cytometry
Authors: Woods Travis A. , Graves Steven W. , Nolan John P.
Published: September 2008

This unit describes an extrinsic staining protocol using the amine‐reactive CBQCA dye to measure the amount of protein on the surface of a microsphere. This approach is novel in that it allows microspheres bearing proteins without known binding partners to be accurately quantified on a flow cytometer.
Evaluation of Risk Communication Efforts
Authors: Jardine Cynthia G.
Published: September 2008

Evaluation is a critical component of risk communication. However, it is frequently overlooked when planning and implementing risk communication efforts. The many compelling reasons for conducting evaluation and the various types of evaluation are explored. Some key factors required for successful evaluation are also discussed. Finally, some recognized barriers to conducting evaluation are presented. Evaluation needs to be considered as a required component of any risk communication program, or we doom ourselves to forever repeating the same mistakes instead of building on our successes.
Comparative Risk Assessment
Authors: Ray Rose M.
Published: September 2008

Comparative risk assessment is an analytic process of evaluating and ranking the different factors that contribute to a particular outcome, such as human disease. The term
comparative risk assessment
is most frequently used in the context of environmental risk, but the principles and methodology are applicable in other contexts.

Comparative risk assessment is both a scientific and political process. Scientific methods are used to gather data, classify the type and severity of risks, and identify and verify relationships between outcomes and risk factors. As it is a guide to decision making, comparative risk assessment also involves the political functions of defining the scope of the assessment, involving stakeholders in the process, and putting the results into a context that can be used to develop consensus concerning appropriate action.

This article reviews the history of comparative risk assessment for environmental risk, discusses methods of risk ranking used in environmental risk, reviews methods of communicating risk, considers a few examples of comparative risk assessment in nonenvironmental areas, and touches on United States Environmental Protection Agency (USEPA) and other regulations as they relate to comparative risk assessment.
History and Examples of Environmental Justice
Authors: Restrepo Carlos E. , Zimmerman Rae
Published: September 2008

Environmental justice has become an influential policy discourse and analysis tool over the last few decades with particular importance for risk management. This article examines the evolution of the environmental justice movement in the United States, the main research tools used in the field, and their potential use and adaptation for incorporating justice into risk problems. The environmental justice discourse in international policy issues such as climate change and transboundary movements of hazardous and toxic substances, and its use within the sustainable development field are also discussed. Although literature reviews of environmental justice analysis suggest that there is strong evidence of environmental inequities, many research challenges exist related to the measurement of individual and multiple exposures to environmental risks and their link to human health outcomes. Understanding these links among different population groups is an area of active research and represents critical future research directions in the field.
Economic Criteria for Setting Environmental Standards
Authors: Ricci Paolo F.
Published: September 2008

This paper includes aspects of economic regulations and discussions of some of the legal aspects affecting those regulations.The discussions are based on US and EU examples and introduce several aspects and consequences of the combined role of economics and law in attempts to regulate pollution emissions and exposures to reduce risk to health and the environment.
Scenario‐Based Risk Management and Simulation Optimization
Authors: Better Marco , Glover Fred
Published: September 2008

Traditional optimization approaches for handling uncertainty and risk typically require severe assumptions that are often not satisfied in complex practical settings. In an effort to overcome such limitations, several methods have been developed to handle uncertainty when the data and associated real‐world parameters do not behave according to classical assumptions. Two of the leading and most widely used examples are scenario optimization and robust optimization, both of which seek high‐quality decisions that are feasible for all scenarios. However, both of these approaches likewise succumb to deficiencies encountered by classical methods, by exhibiting serious limitations in terms of the complexity and size of the models they can handle. Simulation optimization overcomes these limitations, and its flexibility and ease of use has contributed to its popularity as a preferred optimization approach to risk‐management applications.
Risk Management of Construction Defects
Authors: Steffey Duane L.
Published: September 2008

Risk management of construction defects involves the collection and analysis of data to ascertain the empirical basis for alleged defects and to assess the producer's or consumer's risk regarding possible actions. In the context of a dispute between two or more parties, risk managers also make decisions concerning alternative options for resolution. Defects are usually identified through quality inspections and tests during construction or sometimes through the manifestation of problems after the completion of construction. Statistical sampling and estimation are used to characterize the prevalence of defects. Important considerations include the selection of a suitable sampling design, determination of an adequate sample size, and control of potential sources of bias. Defects attributable to design, materials, and method of construction may require qualitatively different approaches compared to the sampling plans implemented for defects attributable to workmanship. Repair options often vary in scope and unit cost, with implications for the associated financial risks.
Managing Infrastructure Reliability, Safety, and Security
Authors: Zimmerman Rae
Published: September 2008

Infrastructure reliability, in its most general sense, refers to whether a system performs as expected. Reliability is relative, depending on the perspective of the infrastructure user. Safety and security are key components for the concept of reliability, since they pertain to basic survival, and are prerequisites for others. Safety and security are defined, and their emergence as core concepts in infrastructure reliability is described. Infrastructure security now relates to a set of critical infrastructures. Factors that potentially compromise infrastructure security include how infrastructure is spatially distributed and interrelated or interdependent with other infrastructures. Risk‐based analytical approaches, and alternatives to these approaches, have arisen to address the likelihood and form of attacks as well as the consequences of attacks on infrastructure. Selected examples of these methodologies are presented. Resource allocation at the federal level emphasizes a risk‐based approach, though the nature of risks faced by critical infrastructures, how these risks should be quantified, what analytical tools should be used to produce such estimates, at what geographic scale, and how they are to be incorporated into prioritization schemes are still a subject of considerable debate.
Benchmark Analysis
Authors: Crump Kenny S.
Published: September 2008

Benchmark analysis is a statistical tool used to set guidelines for exposures to toxic substances. The benchmark dose (BMD) is a dose or exposure level to a toxin that corresponds to a predetermined increase in risk (benchmark risk or BMR) of an adverse health response. An exposure guideline is set by dividing a statistical lower bound on the BMD (BMDL) by factors that account for various limitations in the underlying database for the toxin. Previously, a no‐observed‐adverse‐effect‐level (NOAEL) was used in place of the BMDL. The BMDL offers several advantages over the NOAEL, including better accounting for the shape of the dose–response and the size of the study. Issues that need to be resolved in a BMD analysis include the choice of the BMR, the mathematical form assumed for the dose–response, and how to reconcile BMD calculated from binary and continuous endpoints.
Canonical Modeling
Authors: Voit Eberhard O.
Published: September 2008

In contrast to probabilistic risk assessments in industry, environmental and health risk assessments require dynamic models that capture the essence of complex biological systems. Canonical models withinbiochemical systems theoryare particularly well suited, as they can represent any degree of complexity, yet allow for streamlined mathematical and computational analyses.
Combining Information
Authors: Piegorsch Walter W. , Bailer A. John
Published: September 2008

An area of growing importance in quantitative risk analysis concerns the combination of information from diverse sources. A common rubric for combining the results of independent studies is
meta‐analysis
. The goal of the methodology is to bring together results of different studies, reanalyze the disparate results within the context of their common endpoints, increase the sensitivity of the analysis to detect the presence of adverse effects, and provide a quantitative analysis of the phenomenon of interest based on the combined data. This entry discusses some basic methods in meta‐analytic calculations, and includes commentary on how to combine or average results from multiple models applied to the same set of data.
Ecological Risk Assessment
Authors: Fox David R. , Burgman Mark
Published: September 2008

Increasingly, difficult decisions concerning human activities which have the potential to negatively impact environmental assets are being underpinned by ecological risk assessments. While this approach has much to offer, it is nevertheless a relatively new approach that still faces considerable technical and social challenges.
Environmental Monitoring
Authors: McBean Edward A. , Sharma Mukesh
Published: September 2008

While risk assessment and management procedures are now widely employed, the need for routine and specific environmental monitoring is demonstrated as important inputs to the procedures. Approaches for defining the conceptual framework for risk assessment are provided, including the need to assemble data to assist in quantifying the chemicals in each of the environmental media (e.g., air, soil, and water) and the transformation between media. The elements of food‐chain modeling are described, to demonstrate how the migration pathways may develop between media and elements of the food chain. Specific examples of migration and transformations of chemicals in the environment are explored, with reference to statistical procedures to assist in the data characterization.
Extreme Event Risk
Authors: Brillinger David R.
Published: September 2008

“Extreme event” is a vague concept with a variety of formal definitions based on specific cases and contexts. Particular extreme events include, great earthquakes, floods, droughts, nuclear meltdowns, space shuttle losses, deaths, giant sea waves, stock crashes, landslides, storms, hurricanes, tornadoes, wildfires, and consequences of any of the preceding. The event of interest might be caused by man or by nature. They may occur in time or space. The size might be measured in deaths or costs. The study of extreme event situations has led to important research results and management methods. The specific concern of the entry is quantitative formulation of the problem.
Fate and Transport Models
Authors: Pistocchi Alberto
Published: September 2008

In the following section we provide general background information about mathematical descriptions of phase partitioning of chemicals, mechanisms of their transfer between and within environmental media, and degradation, also introducing the most common mathematical representations of the processes described. Eventually, such representations are combined in a general equation used for fate and transport modeling: the advection–dispersion–reaction equation (ADRE). The processes described by the ADRE are very general; depending on the specific medium (soil, water, air) where they take place, the different terms of the equation are represented differently.

In a subsequent section, we describe specific cases of the ADRE in relation to surface water, soil/groundwater, and air, which are the domains where it is normally solved. For each case, we introduce some examples of publicly available computing codes that solve the equation.

In the last section, we introduce multimedia/multispecies fate and transport of chemicals using linear box models.
Gene–Environment Interaction
Authors: Umbach David M.
Published: September 2008

Current biomedical research is guided by the idea that genetic makeup and environmental exposures, broadly construed, work together through time to cause human disease. This idea is the broad essence of gene–environment interaction. The detailed assessment of gene–environment interaction using epidemiologic data involves issues such as how one defines such interactions in a statistical sense and how one might infer that interactions seen in observational studies reflect causal relationships. That gene–environment interaction is hard to detect and estimate, requiring much larger sample sizes than main effects, has prompted research into novel approaches to increase power and precision through both methods of data analysis methods and study designs. Efforts to make studies robust against hidden genetic population structure have prompted other innovations in study design. The needs of biomedical science continue to stimulate research toward improved methods for studying gene–environment interaction.
Global Warming
Authors: Tebaldi Claudia , Mastrandrea Michael D. , Smith Richard L.
Published: September 2008

Global warming is a worldwide environmental, social, and economic challenge, with far‐reaching implications for human welfare and the health of natural systems. While this qualitative assessment is generally agreed upon by a large share of scientific, policy‐making, and stakeholder communities, a quantification of the risks associated with global warming is far from straightforward. There exist considerable uncertainties, including limits to predicting future changes in the drivers of greenhouse gas emissions (population, economic growth, etc.), incomplete scientific understanding of the response of the climate system to those emissions, and components of intrinsic randomness or unpredictability in the processes involved. From the size of the changes to be expected to their timing and from the significance of impacts to the costs of adaptation and mitigation strategies, every link of the chain from emissions, to impacts, to the effects of policy is affected by uncertainties. This article characterizes the main sources of uncertainty in modeling of the climate system and in the development of scenarios for future emissions, as well as the most rigorous efforts currently documented in the peer reviewed literature to quantify uncertainty and incorporate it into risk analysis.
Hazardous Waste Site(s)
Authors: Carlon Claudio
Published: September 2008

Hazardous waste sites are portions of land contaminated by voluntary or involuntary introduction of hazardous substances. In their several millions worldwide, they pose a relevant risk to human health and the environment. Hazardous substances can spread in the environment through volatilization, particle suspension, and water leaching. Relevant exposure to these substances can occur to residents, workers, and trespassers as well as to plants, soil organisms, birds, mammals, and fishes. Risk assessment methodologies are employed to rank sites at regional scale, to develop generic soil quality standards and to assess the risk, and tailor remediation interventions at specific site locations. It is usually a retrospective risk assessment, since the exposure has been occurring at the time of the study. The fundamentals and front‐edge developments of these methodologies are introduced and related to risk‐management practices.
Latin Hypercube Sampling
Authors: Iman Ronald L.
Published: September 2008

This chapter discusses the use of computer models for such diverse applications as safety assessments for geologic isolation of radioactive waste and for nuclear power plants; loss cost projections for hurricanes; reliability analyses for manufacturing equipment; transmission of HIV; and subsurface storm flow modelling. Such models are usually characterized by a large number of input variables (perhaps as many as a few hundred), and usually, only a handful of these inputs are important for a given response. In addition, the model response is frequently multivariate and time dependent. Latin hypercube sampling (LHS) uses a stratified sampling scheme to improve on the coverage of thek‐dimensional input space for such computer models. This means that a single sample will provide useful information when some input variable(s) dominate certain responses (or certain time intervals), while other input variables dominate other responses (or time intervals). By sampling over the entire range, each variable has the opportunity to show up as important, if it indeed is important. If an input variable is not important, then the method of sampling is of little or no concern. The values of the stratified sampling scheme can be paired to ensure a desired correlation structure among thekinput variables. LHS is more efficient than simple random sampling in a large range of conditions.
Low‐Dose Extrapolation
Authors: Piegorsch Walter W.
Published: September 2008

Issues of extrapolation in risk analytic studies are reviewed for cases where the design of a study requires the data to be taken at fairly high‐dose levels, but where decisions on occupational or environmental exposure standards to a toxic agent must be extrapol ated from the high‐dose exposure data to low‐dose levels of the agent.
Modifiable Areal Unit Problem (
MAUP
)
Authors: Sexton Ken
Published: September 2008

Deciding on an appropriate research design, interpreting study results, or choosing a suitable public policy to mitigate environmental risk implies a decision, either implicit or explicit, about spatial scale and resolution. The modifiable areal unit problem (MAUP) is a formal statement of the dilemma facing researchers, risk assessors, and policy makers when they use geographical data—results of statistical analyses usually depend on subjective decisions about geographical units of analysis and the level of data aggregation within those units. Consideration of the MAUP is essential for the development of effective and efficient strategies for managing environmental health risks.
Potency Estimation
Authors: Bailer A. John , Piegorsch Walter W.
Published: September 2008

A common goal in environmental risk assessment is description of the hazardous agent's toxic or otherwise‐harmful effects, often for comparison with others agents of related structure or exposure. Summary measures are most useful in this regard, as these describe the potency of an agent or some product of an agent on the organism or system under study. A number of quantitative summaries can be used to measure or define potency, each based on a slightly different feature of the observed dose–response. We consider a few of these in this article.
Precautionary Principle
Authors: Grandjean Philippe , Keiding Niels
Published: September 2008

The
precautionary principle
is a term used about a set of statements all expressing the general intention that, in environmental risk policy, it is prudent to not always wait for definitive proof of harm before taking regulatory action. We present the concept and outline its relation to scientific discovery and statistical uncertainty.
Remote Sensing
Authors: Myers Wayne , Patil Ganapathi P.
Published: September 2008

Risk assessment requires information on exposure, sensitivity, condition, and resiliency of entities under investigation. In environmental contexts, this typically requires geographically specific information that can often be obtained most quickly and at least cost through remote sensing in conjunction with geographic information systems (GISs). We introduce and illustrate major aspects of remote sensing using forest fires as an example context. Signal selection is considered for the electromagnetic spectrum, along with formulation of pseudosignals as environmental indicators. Conventional classification sets the stage for modeling of spatial interaction among signals as polypatterns. Detection of landscape changes is considered in both conventional and image modeling modes. Need for partnership between remote sensing analyst and risk analyst is underscored.
Soil Contamination Risk
Authors: Carlon Claudio
Published: September 2008

Soil is a “vital” medium hosting most of the biosphere and is essentially a non‐renewable natural resource owing to the very slow processes under its generation. It has fundamental functions in the water and biogeochemical cycles. It is also the platform for human activities and landscape. The old idea that soil could degrade any sort and amount of contamination without being affected in its functioning has been found incorrect, and it is now recognized that soil protection is highly relevant for conservation of the terrestrial ecosystem, for the safeguard of human health, and for agriculture. Risk assessment methodologies have been developed for assessing the risk posed by soil contaminants to the terrestrial ecosystem and to human health. They have to deal with a large number of uncertainties owing to poor knowledge and limited modeling capability. An overview of sources of uncertainty is provided for both human health and ecological risk assessment. This is followed by a description of how soil quality standards are the product of sound science and conventional assumptions depending on risk societal valuing.
Spatiotemporal Risk Analysis
Authors: Lawson Andrew B.
Published: September 2008

This article focuses on the issues related to risk assessment when the domain consists of space and time. Spatiotemporal risk assessment could involve separate analyses of risk in a geographical domain, risk in a temporal window, or the interaction of space and time. Often the focus will be on magnitude and frequency of an outcome but this will have a spatial and temporal expression. The link with surveillance for adverse outcomes is made, and health risk is a focus of the review, although the concepts illustrated can be applied in other areas such as financial or industrial risk analysis.
Vulnerability Analysis for Environmental Hazards
Authors: Cutter Susan L.
Published: September 2008

This entry details a spatial social science perspective for environmental hazards vulnerability analysis. Vulnerability science is an interdisciplinary approach that integrates the characteristics of potential hazards such as magnitude, frequency, and duration (physical vulnerability) with characteristics of people and the built environment that either increase or decrease their impacts (social vulnerability). It is the combination of the physical and social processes and associated outcomes that contribute to the overall vulnerability of places. Spatial social science methods and tools (such as geographic information systems) provide the integrative mechanism for comparing vulnerability at various geographic scales such as census tracts, counties, or cities.