bluuebunny/crossref_metadata_2025 huggingface dataset:
CONTROL OF REPRODUCTION RHYTHMICITY BY ENVIRONMENTAL AND ENDOGENOUS SIGNALS INULVA PSEUDOCURVATA(CHLOROPHYTA)1
Authors: Lüning Klaus , Kadel Petra , Pang Shaojun
Published: June 2008

A field population ofUlva pseudocurvataKoeman et C. Hoek (hereafter termedUlva) at Sylt Island (North Sea, Germany) exhibited biweekly peaks of gametophytic reproduction during the colder seasons and approximately weekly peaks during summer. The reproductive events lasted 1–5 d and were separated from each other by purely vegetative phases. Under constant conditions in the laboratory, a free‐running rhythm was observed with reproductive peaks occurring approximately every 7 d. When artificial moonlight was provided every 4 weeks, fewer reproductive events occurred, and the reproductive rhythm became synchronized to the environmental artificial moonlight rhythm. In the laboratory, apical disks were entirely converted into reproductive tissue after 8 d cultivation, while almost all basal disks stayed vegetative, which prevented the entire loss of the vegetative thallus during reproductive events. Seasonal size reduction of the thallus occurred from late autumn onward and was determined to be controlled by a genuine photoperiodic response, since size reduction could be induced from May onward by experimental short‐day (SD) treatment but was prevented in a long‐day (LD) or night‐break regime (NB). A daily fine‐tuning occurred with gamete release early in the morning at the first sign of daylight, following an obligatory dark (“night”) period of at least 1 h duration. No release took place if the overnight dark phase was replaced by continuous light. Blue, green, or red light all triggered gamete release after a dark phase at an irradiance of 0.1 μmol photons · m−2 ·s−1, while 0.001 μmol photons · m−2 · s−1was equivalent to a dark control.
PHYLOGENY OF THE EUGLENALES INFERRED FROM PLASTID LSU rDNA SEQUENCES1
Authors: Kim Jong Im , Shin Woongghi
Published: June 2008

To gain insights into the phylogeny of the Euglenales, we analyzed the plastid LSU rDNA sequences from 101 strains of the photosynthetic euglenoids belonging to nine ingroup genera (Euglena, Trachelomonas, Strombomonas, Monomorphina, Cryptoglena, Colacium, Discoplastis, Phacus, and Lepocinclis) and two outgroup genera (Eutreptia and Eutreptiella). Bayesian and maximum‐likelihood (ML) analyses resulted in trees of similar topologies and four major clades: a Phacus and Lepocinclis clade; a Colacium clade; a Trachelomonas, Strombomonas, Monomorphina, and Cryptoglena clade; and a Euglena clade. The Phacus and Lepocinclis clade was the sister group of all other euglenalian genera, followed by Discoplastis spathirhyncha (Skuja) Triemer and the Colacium clade, respectively, which was inconsistent with their placement based on nuclear rDNA genes. The Trachelomonas, Strombomonas, Monomorphina, and Cryptoglena clade was sister to the Euglena clade. The loricate genera, Trachelomonas and Strombomonas, were closely related to each other, while Monomorphina and Cryptoglena also grouped together. The Euglena clade formed a monophyletic lineage comprising most species from taxa formerly allocated to the subgenera Calliglena and Euglena. However, within this genus, none of the subgenera was monophyletic.
PHOTOSYNTHESIS AND PRODUCTION OF HYDROGEN PEROXIDE BY SYMBIODINIUM (PYRRHOPHYTA) PHYLOTYPES WITH DIFFERENT THERMAL TOLERANCES1
Authors: Suggett David J. , Warner Mark E. , Smith David J. , Davey Phillip , Hennige Sebastian , Baker Neil R.
Published: June 2008

Occurrences whereby cnidaria lose their symbiotic dinoflagellate microalgae (Symbiodinium spp.) are increasing in frequency and intensity. These so‐called bleaching events are most often related to an increase in water temperature, which is thought to limit certain Symbiodinium phylotypes from effectively dissipating absorbed excitation energy that is otherwise used for photochemistry. Here, we examined photosynthetic characteristics and hydrogen peroxide (H2O2) production, a possible signal involved in bleaching, from two Symbiodinium types (a thermally “tolerant” A1 and “sensitive” B1) representative of cnidaria–Symbiodinium symbioses of reef‐building Caribbean corals. Under steady‐state growth at 26°C, a higher efficiency of PSII photochemistry, rate of electron turnover, and rate of O2 production were observed for type A1 than for B1. The two types responded very differently to a period of elevated temperature (32°C): type A1 increased light‐driven O2 consumption but not the amount of H2O2 produced; in contrast, type B1 increased the amount of H2O2 produced without an increase in light‐driven O2 consumption. Therefore, our results are consistent with previous suggestions that the thermal tolerance of Symbiodinium is related to adaptive constraints associated with photosynthesis and that sensitive phylotypes are more prone to H2O2 production. Understanding these adaptive differences in the genus Symbiodinium will be crucial if we are to interpret the response of symbiotic associations, including reef‐building corals, to environmental change.
AN ECOLOGICAL REVIEW OFCLADOPHORA GLOMERATA(CHLOROPHYTA) IN THE LAURENTIAN GREAT LAKES1
Authors: Higgins Scott N. , Malkin Sairah Y. , Todd Howell E. , Guildford Stephanie J. , Campbell Linda , Hiriart‐Baer Veronique , Hecky Robert E.
Published: June 2008

Cladophora glomerata(L.) Kütz. is, potentially, the most widely distributed macroalga throughout the world’s freshwater ecosystems.C. glomeratahas been described throughout North America, Europe, the Atlantic Islands, the Caribbean Islands, Asia, Africa, Australia and New Zealand, and the Pacific Islands.Cladophorablooms were a common feature of the lower North American Great Lakes (Erie, Michigan, Ontario) from the 1950s through the early 1980s and were largely eradicated through the implementation of a multibillion‐dollar phosphorus (P) abatement program. The return of widespread blooms in these lakes since the mid‐1990s, however, was not associated with increases in P loading. Instead, current evidence indicates that the resurgence in blooms was directly related to ecosystem level changes in substratum availability, water clarity, and P recycling associated with the establishment of dense colonies of invasive dreissenid mussels. These results support the hypothesis that dreissenid mussel invasions may induce dramatic shifts in energy and nutrient flow from pelagic zones to the benthic zone.
The Effects of Neuropeptide S on Ethanol Drinking and Other Related Behaviors in Alcohol‐Preferring and ‐Nonpreferring Rats
Authors: Badia‐Elder Nancy E. , Henderson Angela N. , Bertholomey Megan L. , Dodge Neil C. , Stewart Robert B.
Published: June 2008

Background.  Neuropeptide S (NPS) is a 20‐amino‐acid peptide, identified in the brain and periphery, that is reported to regulate arousal, anxiety, and feeding behavior. Studies were conducted to determine whether this peptide would alter ethanol intake, sucrose intake, anxiety, and general motor activity in alcohol‐preferring (P) and ‐nonpreferring (NP) rats.

Methods.  Experiment 1: P and NP rats were given 8 weeks of continuous access to ethanol (15% w/v) and water. All rats were implanted with a cannula aimed at either the left or right lateral ventricle and 1 week later were infused with NPS (0.075, 0.3, 1.2 nmol) or artificial cerebrospinal fluid (aCSF) and tested for ethanol, food, and water intake. Experiment 2: The same doses of NPS were administered to a group of P rats and intake of 2.5% (w/v) sucrose was measured. Experiment 3: Infusions of NPS (1.2 nmol) or aCSF were administered to P rats prior to a 5‐minute test on an elevated plus maze. Experiment 4: Ethanol naive P and NP rats were infused with NPS (0.075, 0.15, 0.3, 0.6, and 1.2 nmol) or aCSF prior to a 20‐minute test in activity monitors.

Results.  NPS reduced ethanol intake in P, but not in NP rats. It did not influence sucrose solution intake in P rats. However, an increase in food intake was seen in both rat lines following lower doses of the peptide. NPS did neither alter anxiety‐like behavior in the elevated plus maze test nor was there an effect on general motor activity; however, there was an increase in the amount of time spent in the center of the activity monitors following infusions of 0.6 nmol of NPS in P, but not in NP rats, indicating anxioltyic actions of the peptide.

Conclusions.  These data suggest a role for NPS in the modulation of ethanol drinking and possibly anxiety‐like behavior in rats selectively bred for high alcohol drinking.
Correspondence Between Secular Changes in Alcohol Dependence and Age of Drinking Onset Among Women in the United States
Authors: Grucza Richard A. , Norberg Karen , Bucholz Kathleen K. , Bierut Laura J.
Published: June 2008

Background:  Several lines of evidence suggest that the lifetime prevalence of alcohol dependence among women has increased in recent decades, but has not risen significantly for men. Early age at onset of drinking (AOD) is strongly correlated with risk for alcohol dependence and there is evidence that mean AOD has also decreased, particularly for women. The present report sought to confirm the trends in AOD and to determine the extent to which they might account for secular trends in alcohol dependence.

Methods:  Repeated cross‐sectional analyses of data from 2 large, national epidemiological surveys were conducted to enable estimates of cross‐cohort differences while controlling for age‐related factors. Regression analyses were used to compute risk for alcohol dependence associated with birth cohort membership, before and after inclusion of AOD as a covariate.

Results:  Both men and women born between 1944 and 1963 had earlier ages of onset for drinking than did the earliest birth cohort analyzed (1934–43). However, the net decrease in AOD was twice as large for women (3.2 years) than that for men (1.6 years). After adjusting for AOD, differences in lifetime prevalence between different birth cohorts of women were rendered nonsignificant, indicating that AOD accounts for a substantial portion of change in the lifetime prevalence of alcohol dependence.

Conclusions:  These results suggest that a decrease in AOD accounts for much of the increase in lifetime alcohol dependence among women. AOD is likely to be an indicator of dynamic, and therefore modifiable risk behaviors impacting risk for alcohol dependence.
Prevention of D sensitization after mismatched transfusion of blood components: toward optimal use of RhIG
Authors: Ayache Saleh , Herman Jay H.
Published: June 2008

Transfusion of D+ red blood cells (RBCs) into D− recipients, whether through whole blood, RBC, or platelet (PLT) transfusion, can lead to alloimmunization with associated risks of hemolytic reactions from subsequent mismatched transfusion. The incidence of D alloimmunization in various transfused patient populations may be different from that reported in normal subjects or in pregnancy, but prevention of D alloimmunization after mismatched transfusion can be achieved using RhIG. An optimal approach to the use of RhIG, however, has not been identified for the United States. Case histories and studies of volunteers reported over the past 40 years have established that alloimmunization to mismatched RBC transfusion can be successfully prevented with a dose of 20 µg of RhIG per 1 mL of D+ RBCs (per 2 mL of whole blood) when given within a window of opportunity that extends to at least 72 hours. Evidence from prospective studies of RhIG as a therapy for immune thrombocytopenic purpura suggests that such doses can be tolerably given by intravenous injections over short periods, with adverse event rates minimized when pretransfusion medication is given. For mismatched PLT transfusions, the lowest dose of standard preparations of RhIG (e.g., 125 or 300 µg) should be sufficient to prevent alloimmunization given the small D+ RBC volumes involved. This article reviews how our understanding of prevention of alloimmunization in mismatched transfusion has progressed over the years and outlines some practical considerations based on the currently available evidence.
The role of donor antibodies in the pathogenesis of transfusion‐related acute lung injury: a systematic review
Authors: Middelburg Rutger A. , Van Stein Daniëlle , Briët Ernest , Van Der Bom Johanna G.
Published: June 2008

BACKGROUND: The majority of cases of transfusion‐related acute lung injury (TRALI) are thought to be caused by the presence of leukocyte antibodies in the blood of the donor. We performed a systematic search of the literature to quantify the contribution of donor antibodies to the occurrence of TRALI.

STUDY DESIGN AND METHODS: We conducted a systematic search of the PubMed and EMBASE databases. Retrieved articles were judged by three authors independently. Reference lists of all articles were subsequently screened for relevant references. All articles in English, German, French, and Dutch, published at any time before December 2007, were eligible for inclusion.

RESULTS: Of 77 articles on leukocyte antibodies in donors involved in a case of TRALI, 14 articles contained sufficient data. These 14 articles reported leukocyte antibodies in 24 of 51 donors (47%) associated with 24 of 28 TRALI cases (86%). Of 15 articles that reported the prevalence of leukocyte antibodies in the general donor population, 2 articles reported a prevalence of 17 percent in (452) randomly selected donors. The odds ratio for developing TRALI was 15 (95% confidence interval [CI], 5.1‐45) for patients who received a transfusion from a donor who tested positive for the presence of leukocyte antibodies, compared to donors who tested negative. Leukocyte antibodies contributed to 80 percent (95% CI, 51%‐92%) of all TRALI cases.

CONCLUSION: Leukocyte antibodies were more prevalent in donors involved in TRALI cases than among randomly selected donors. These findings suggest that donor antibodies contribute to four‐fifths of all TRALI cases.
Combining Occurrence and Toxicity Information to Identify Priorities for Drinking‐Water Mixture Research
Authors: Ryker Sarah J. , Small Mitchell J.
Published: June 2008

Characterizing all possible chemical mixtures in drinking water is a potentially overwhelming project, and the task of assessing each mixture's net toxicity even more daunting. We propose that analyzing occurrence information on mixtures in drinking water may help to narrow the priorities and inform the approaches taken by researchers in mixture toxicology. To illustrate the utility of environmental data for refining the mixtures problem, we use a recent compilation of national ground‐water‐quality data to examine proposed U.S. Environmental Protection Agency (EPA) and Agency for Toxic Substances and Disease Registry (ATSDR) models of noncancer mixture toxicity. We use data on the occurrence of binary and ternary mixtures of arsenic, cadmium, and manganese to parameterize an additive model and compute hazard index scores for each drinking‐water source in the data set. We also use partially parameterized interaction models to perform a bounding analysis estimating the interaction potential of several binary and ternary mixtures for which the toxicological literature is limited. From these results, we estimate a relative value of additional toxicological information for each mixture. For example, we find that according to the U.S. EPA's interaction model, the levels of arsenic and cadmium found in U.S. drinking water are unlikely to have synergistic cardiovascular effects, but the same mixture's potential for synergistic neurological effects merits further study. Similar analysis could in future be used to prioritize toxicological studies based on their potential to reduce scientific and regulatory uncertainty. Environmental data may also provide a means to explore the implications of alternative risk models for the toxicity and interaction of complex mixtures.
How Do Disaster Characteristics Influence Risk Perception?
Authors: Ho Ming‐Chou , Shaw Daigee , Lin Shuyeu , Chiu Yao‐Chu
Published: June 2008

The main purpose of this study is to examine how risk perception is influenced by the type of disaster (flood or landslide) and victim characteristics. The data reported here are based on the National Risk Perception Survey (NRPS) that was administered for the victims and the general public in Taiwan in 2004. In that year, many towns in Taiwan were seriously affected by floods and landslides, resulting in huge economic losses and fatalities. The primary findings are: (1) the victims and the general public are concerned about the different potential hazards that might affect their residential area, (2) the negative associations between the sense of controllability and the perceived impact is high for landslide victims, but not for flood victims, and (3) disaster type, gender, and previously experienced disasters are good predictors of victims' attitudes toward natural disasters.
Regulating Under Uncertainty: Newsboy for Exposure Limits
Authors: Cooke Roger M. , MacDonell Margaret
Published: June 2008

Setting action levels or limits for health protection is complicated by uncertainty in the dose‐response relation across a range of hazards and exposures. To address this issue, we consider the classic newsboy problem. The principles used to manage uncertainty for that case are applied to two stylized exposure examples, one for high dose and high dose rate radiation and the other for ammonia. Both incorporate expert judgment on uncertainty quantification in the dose‐response relationship. The mathematical technique of probabilistic inversion also plays a key role. We propose a coupled approach, whereby scientists quantify the dose‐response uncertainty using techniques such as structured expert judgment with performance weights and probabilistic inversion, and stakeholders quantify associated loss rates.
Is the Way Young People Drive a Reflection of the Way Their Parents Drive? An Econometric Study of the Relation Between Parental Risk and Their Children's Risk
Authors: Lahatte Agénor , Le Pape Marie‐Clémence
Published: June 2008

This article aims to investigate parental influence on high‐risk behavior by young people. Although research on the topic of perception of risk demonstrates that it is socially constructed, the role of the family in this construction has rarely been studied. Using a French national survey of more than 1,200 young drivers between the ages of 18 and 25, and their parents, we attempt to understand the transmission of risk within families. Our econometric study shows that parents influence both the practices and representations of their children. When parental norms and values are transmitted, they are by no means accepted in a wholly passive way. Indeed, the parental model is in competition with other models that originate from both inside the family (brothers and sisters) and outside it (instructors). Furthermore, parental influence decreases over time as young people become more experienced drivers and construct their own identity with regard to risk.
Reducing Risk on Machinery: A Field Evaluation Pilot Study of Risk Assessment
Authors: Etherton John , Main Bruce , Cloutier Dennis , Christensen Wayne
Published: June 2008

A pilot evaluation of the ANSI B11‐TR3 Machinery Risk Assessment/Risk Reduction (RA/RR) Guideline was conducted. The TR3 guideline was introduced into five companies on one machinery system in each company with a second machine system serving as a control. A pre‐post investigation was performed with safety conditions measured pre and post in both treatment and control and with risk reduction score measured only in the treatment machine system. NIOSH provided a commercially available risk assessment software to facilitate the process. Evaluation measures included avoided injuries, reduced exposure to machinery hazards, pretest and posttest knowledge demonstration, assessment of group processes following training, correct implementation of the guidelines, and degree to which risk reduction recommendations were implemented. The qualitative results of this pilot effort appear to be the best indicators for the way ahead in industrial machine risk assessment. All companies indicated that they derived value in participating in this study and in conducting risk assessments. Quantitative study results suggest that: (1) as measured by the knowledge of the participants before and after the TR3 training, the guidelines can be effective at enhancing employee knowledge of safe machine operations and (2) although the injury reduction trends appear successful, the small sample size in the study size should be considered in interpreting these early results.
An Adaptive Regional Input‐Output Model and its Application to the Assessment of the Economic Cost of Katrina
Authors: Hallegatte Stéphane
Published: June 2008

This article proposes a new modeling framework to investigate the consequences of natural disasters and the following reconstruction phase. Based on input‐output tables, its originalities are (1) the taking into account of sector production capacities and of both forward and backward propagations within the economic system; and (2) the introduction of adaptive behaviors. The model is used to simulate the response of the economy of Louisiana to the landfall of Katrina. The model is found consistent with available data, and provides two important insights. First, economic processes exacerbate direct losses, and total costs are estimated at $149 billion, for direct losses equal to $107 billion. When exploring the impacts of other possible disasters, it is found that total losses due to a disaster affecting Louisiana increase nonlinearly with respect to direct losses when the latter exceed $50 billion. When direct losses exceed $200 billion, for instance, total losses are twice as large as direct losses. For risk management, therefore, direct losses are insufficient measures of disaster consequences. Second, positive and negative backward propagation mechanisms are essential for the assessment of disaster consequences, and the taking into account of production capacities is necessary to avoid overestimating the positive effects of reconstruction. A systematic sensitivity analysis shows that, among all parameters, the overproduction capacity in the construction sector and the adaptation characteristic time are the most important.
Preventive Health Behavior and Adaptive Accuracy of Risk Perceptions
Authors: Renner Britta , Schüz Benjamin , Sniehotta Falko F.
Published: June 2008

This study examined the relation between health behavior and risk perceptions in the context of an acute livestock epidemic. Participants in a longitudinal web‐based survey (N= 195) were asked to report their meat consumption and their perceived risk in relation to bovine spongiform encephalopathy (BSE) and other related livestock diseases. Cross‐sectional analyses at both measurement points (T1 and T2) showed that participants with low levels of preventive nutrition (high meat consumption) felt more at risk for BSE‐related diseases than those reporting comparable higher levels of preventive behavior (low meat consumption), indicating relative accuracy. These results suggest that people recognize when their behavior is risky. More importantly, perceived risk also showed adaptive accuracy from a change perspective: increases in preventive nutrition from T1 to T2 were significantly associated with decreases in perceived risk between T1 and T2. Possible foundations and implications of an adaptive accuracy of risk perceptions are discussed.
Quantitative Assessment of Building Fire Risk to Life Safety
Authors: Guanquan Chu , Jinhua Sun
Published: June 2008

This article presents a quantitative risk assessment framework for evaluating fire risk to life safety. Fire risk is divided into two parts: probability and corresponding consequence of every fire scenario. The time‐dependent event tree technique is used to analyze probable fire scenarios based on the effect of fire protection systems on fire spread and smoke movement. To obtain the variation of occurrence probability with time, Markov chain is combined with a time‐dependent event tree for stochastic analysis on the occurrence probability of fire scenarios. To obtain consequences of every fire scenario, some uncertainties are considered in the risk analysis process. When calculating the onset time to untenable conditions, a range of fires are designed based on different fire growth rates, after which uncertainty of onset time to untenable conditions can be characterized by probability distribution. When calculating occupant evacuation time, occupant premovement time is considered as a probability distribution. Consequences of a fire scenario can be evaluated according to probability distribution of evacuation time and onset time of untenable conditions. Then, fire risk to life safety can be evaluated based on occurrence probability and consequences of every fire scenario. To express the risk assessment method in detail, a commercial building is presented as a case study. A discussion compares the assessment result of the case study with fire statistics.
Natural Hazards and Motivation for Mitigation Behavior: People Cannot Predict the Affect Evoked by a Severe Flood
Authors: Siegrist Michael , Gutscher Heinz
Published: June 2008

Past research indicates that personal flood experience is an important factor in motivating mitigation behavior. It is not fully clear, however, why such experience is so important. This study tested the hypothesis that people without flooding experience underestimate the negative affect evoked by such an event. People who were affected by a severe recent flood disaster were compared with people who were not affected, but who also lived in flood‐prone areas. Face‐to‐face interviews with open and closed questions were conducted (n= 201). Results suggest that people without flood experience envisaged the consequences of a flood differently from people who had actually experienced severe losses due to a flood. People who were not affected strongly underestimated the negative affect associated with a flood. Based on the results, it can be concluded that risk communication must not focus solely on technical aspects; in order to trigger motivation for mitigation behavior, successful communication must also help people to envisage the negative emotional consequences of natural disasters.
Concern About Petrochemical Health Risk Before and After a Refinery Explosion
Authors: Cutchin Malcolm P. , Martin Kathryn Remmes , Owen Steven V. , Goodwin James S.
Published: June 2008

On March 23, 2005, a large explosion at an oil refinery in Texas City, Texas caused 15 deaths and approximately 170 injuries. Little is known about how such an industrial accident influences concern about environmental health risks. We used measures of environmental health concern about nearby petrochemical production with a sample of Texas City residents to understand patterns of concern and change in concern after an industrial accident, as well as individual and contextual factors associated with those patterns. Survey interviews with residents of Texas City, Texas (N= 315) both pre‐ and postexplosion using a brief Concern About Petrochemical Health Risk Scale (CAPHRS) and other questions were used to collect pertinent predictor information. CAPHRS baseline, postexplosion, and change scores were compared and modeled using ordinary least squares (OLS) regression and a mixed model. Higher preexplosion CAPHRS scores were predicted by younger adults, foreign‐born Hispanics, non‐Hispanic blacks, lower‐ and middle‐income groups, and those who live with someone who has worked at the petrochemical plants. Higher CAPHRS change scores are predicted by the same variables (except income), as well as proximity to, or perception of, the explosion, and reports of neighborhood damage. Findings suggest these groups' concern scores could indicate a greater vulnerability to psychological and physical harm generated by concern and stress arising from local petrochemical activities. A clearer understanding of concern about actual environmental health risks in exposed populations may enhance the evolving theory of stress and coping and eventually enable public health professionals to develop appropriate mitigation strategies.
Practice‐Specific Risk Perceptions and Self‐Reported Food Safety Practices
Authors: Levy Alan S. , Choinière Conrad J. , Fein Sara B.
Published: June 2008

The relationship between risk perception and risk avoidance is typically analyzed using self‐reported measures. However, in domains such as driving or food handling, the validity of responses about usual behavior is threatened because people think about the situations in which they are self‐aware, such as when they encounter a hazard. Indeed, researchers have often noted a divergence between what people say about their behavior and how they actually behave. Thus, in order to draw conclusions about risk perceptions and risk avoidance from survey data, it is important to identify particular cognitive elements, such as those measured by questions about risk and safety knowledge, risk perceptions, or information search behavior, which may be effective antecedents of self‐reported safety behavior. It is also important to identify and correct for potential sources of bias that may exist in the data. The authors analyze the Food and Drug Administration's 1998 Food Safety Survey to determine whether there are consistent cognitive antecedents for three types of safe food practices: preparation, eating, and cooling of foods. An assessment of measurement biases shows that endogeneity of food choices affects reports of food preparation. In addition, response bias affects reports of cooling practices as evidenced by its relation to knowledge and information search, a pattern of cognitive effects unique to cooling practices. After correcting for these biases, results show that practice‐specific risk perceptions are the primary cognitive antecedents of safe food behavior, which has implications for the design of effective education messages about food safety.
Sensitivity Analysis of Model Output with Input Constraints: A Generalized Rationale for Local Methods
Authors: Borgonovo Emanuele
Published: June 2008

In this work, we introduce a generalized rationale for local sensitivity analysis (SA) methods that allows to solve the problems connected with input constraints. Several models in use in the risk analysis field are characterized by the presence of deterministic relationships among the input parameters. However, SA issues related to the presence of constraints have been mainly dealt with in a heuristic fashion. We start with a systematic analysis of the effects of constraints. The findings can be summarized in the following three effects. (i) Constraints make it impossible to vary one parameter while keeping all others fixed. (ii) The model output becomes insensitive to a parameter if a constraint is solved for that parameter. (iii) Sensitivity analysis results depend on which parameter is selected as dependent. The explanation of these effects is found by proposing a result that leads to a natural extension of the local SA rationale introduced in Helton (1993). We then extend the definitions of the Birnbaum, criticality, and the differential importance measures to the constrained case. In addition, a procedure is introduced that allows to obtain constrained sensitivity results at the same cost as in the absence of constraints. The application to a nonbinary event tree concludes the article, providing a numerical illustration of the above findings.
Optimal Resource Allocation for Defense of Targets Based on Differing Measures of Attractiveness
Authors: Bier Vicki M. , Haphuriwat Naraphorn , Menoyo Jaime , Zimmerman Rae , Culpen Alison M.
Published: June 2008

This article describes the results of applying a rigorous computational model to the problem of the optimal defensive resource allocation among potential terrorist targets. In particular, our study explores how the optimal budget allocation depends on the cost effectiveness of security investments, the defender's valuations of the various targets, and the extent of the defender's uncertainty about the attacker's target valuations. We use expected property damage, expected fatalities, and two metrics of critical infrastructure (airports and bridges) as our measures of target attractiveness. Our results show that the cost effectiveness of security investment has a large impact on the optimal budget allocation. Also, different measures of target attractiveness yield different optimal budget allocations, emphasizing the importance of developing more realistic terrorist objective functions for use in budget allocation decisions for homeland security.
A Stochastic Assessment of the Public Health Risks of the Use of Macrolide Antibiotics in Food Animals
Authors: Hurd H. Scott , Malladi Sasidhar
Published: June 2008

Campylobacteriosis is an important food‐borne illness with more than a million U.S. cases annually. Antibiotic treatment is usually not required. However, erythromycin, a macrolide antibiotic, is recommended for the treatment of severe cases. Therefore, it is considered a critically important antibiotic and given special attention as to the risk that food animal use will lead to resistant infections and compromised human treatment. To assess this risk, we used a retrospective approach; estimating the number of campylobacteriosis cases caused by specific meat consumption utilizing the preventable fraction. We then determined the number of cases with macrolide resistance Campylobacter spp. based on a linear model relating the resistance fraction to on‐farm macrolide use. In this article, we considered the uncertainties in the parameter estimates, utilized a more elaborate model of resistance development and separated C. coli and C. jejuni. There are no published data for the probability of compromised treatment outcome due to macrolide resistance. Therefore, our estimates of compromised treatment outcome were based on data for fluoroquinolone‐resistant infections. The conservative results show the human health risks are extremely low. For example, the predicted risk of suboptimal human treatment of infection with C. coli from swine is only 1 in 82 million; with a 95% chance it could be as high as 1 in 49 million. Risks from C. jejuni in poultry or beef are even less. Reduced antibiotic use can adversely impact animal health. These low human risks should be weighed against the alternative risks.
Mechanistic Modeling of Emergency Events: Assessing the Impact of Hypothetical Releases of Anthrax
Authors: Isukapalli S. S. , Lioy P. J. , Georgopoulos P. G.
Published: June 2008

A modular system for source‐to‐dose‐to‐effect modeling analysis has been developed based on the modeling environment for total risk studies (MENTOR),(1) and applied to study the impacts of hypothetical atmospheric releases of anthrax spores. The system, MENTOR‐2E (MENTOR for Emergency Events), provides mechanistically consistent analysis of inhalation exposures for various release scenarios, while allowing consideration of specific susceptible subpopulations (such as the elderly) at the resolution of individual census tracts. The MENTOR‐2E application presented here includes atmospheric dispersion modeling, statistically representative samples of individuals along with corresponding activity patterns, and population‐based dosimetry modeling that accounts for activity and physiological variability. Two hypothetical release scenarios were simulated: a 100 g release of weaponized B. anthracis over a period of (a) one hour and (b) 10 hours, and the impact of these releases on population in the State of New Jersey was studied. Results were compared with those from simplified modeling of population dynamics (location, activities, etc.), and atmospheric dispersion of anthrax spores. The comparisons showed that in the two release scenarios simulated, each major approximation resulted in an overestimation of the number of probable infections by a factor of 5 to 10; these overestimations can have significant public health implications when preparing for and responding effectively to an actual release. This is in addition to uncertainties in dose‐response modeling, which result in an additional factor of 5 to 10 variation in estimated casualties. The MENTOR‐2E system has been developed in a modular fashion so that improvements in individual modules can be readily made without impacting the other modules, and provides a first step toward the development of models that can be used in supporting real‐time decision making.
Fuzzy Risks and an Updating Algorithm with New Observations
Authors: Huang Chongfu , Ruan Da
Published: June 2008

Concerning the essence of risk, we suggest a new definition of risk: a scene in the future associated with some adverse incident. In many cases, risks are rather fuzzy for our perception because of the shortage of knowledge or information about the systems that determine the adverse incidents. We introduce a concept of fuzzy risk based on the new risk definition and fuzzy sets. And, in this article, we suggest a fuzzy average algorithm to update a fuzzy risk that stores all information from the original data. To illustrate the algorithm, we update a soft risk map of flood where the fuzzy risks are calculated using the interior‐outer‐set model.
Is Probability the Only Coherent Approach to Uncertainty?
Authors: Colyvan Mark
Published: June 2008

In this article, I discuss an argument that purports to prove that probability theory is the only sensible means of dealing with uncertainty. I show that this argument can succeed only if some rather controversial assumptions about the nature of uncertainty are accepted. I discuss these assumptions and provide reasons for rejecting them. I also present examples of what I take to be non‐probabilistic uncertainty.
Risk Communication Planning for the Aftermath of a Plague Bioattack
Authors: Casman Elizabeth A. , Fischhoff Baruch
Published: June 2008

We create an influence diagram of how a plague bioattack could unfold and then use it to identify factors shaping infection risks in many possible scenarios. The influence diagram and associated explanations provide a compact reference that allows risk communicators to identify key messages for pre‐event preparation and testing. It can also be used to answer specific questions in whatever unique situations arise, considering both the conditions of the attack and the properties of the attacked populations. The influence diagram allows a quick, visual check of the factors that must be covered when evaluating audience information needs. The documentation provides content for explaining the resultant advice. We show how these tools can help in preparing for crises and responding to them.
Uncertainties in Biologically‐Based Modeling of Formaldehyde‐Induced Respiratory Cancer Risk: Identification of Key Issues
Authors: Subramaniam Ravi P. , Chen Chao , Crump Kenny S. , DeVoney Danielle , Fox John F. , Portier Christopher J. , Schlosser Paul M. , Thompson Chad M. , White Paul
Published: June 2008

In a series of articles and a health‐risk assessment report, scientists at the CIIT Hamner Institutes developed a model (CIIT model) for estimating respiratory cancer risk due to inhaled formaldehyde within a conceptual framework incorporating extensive mechanistic information and advanced computational methods at the toxicokinetic and toxicodynamic levels. Several regulatory bodies have utilized predictions from this model; on the other hand, upon detailed evaluation the California EPA has decided against doing so. In this article, we study the CIIT model to identify key biological and statistical uncertainties that need careful evaluation if such two‐stage clonal expansion models are to be used for extrapolation of cancer risk from animal bioassays to human exposure. Broadly, these issues pertain to the use and interpretation of experimental labeling index and tumor data, the evaluation and biological interpretation of estimated parameters, and uncertainties in model specification, in particular that of initiated cells. We also identify key uncertainties in the scale‐up of the CIIT model to humans, focusing on assumptions underlying model parameters for cell replication rates and formaldehyde‐induced mutation. We discuss uncertainties in identifying parameter values in the model used to estimate and extrapolate DNA protein cross‐link levels. The authors of the CIIT modeling endeavor characterized their human risk estimates as “conservative in the face of modeling uncertainties.” The uncertainties discussed in this article indicate that such a claim is premature.
A Contingent Model of Network Utilization in Early Financing of Technology Ventures
Authors: Zhang Jing , Souitaris Vangelis , Soh Pek–hooi , Wong Poh–kam
Published: June 2008

Most of the entrepreneurship literature has addressed the benefits and necessity of using social network ties as opposed to market methods in early venture finance, but it has largely understated the potential limitations and costs of doing so. Specifically, very sparse research has examined the factors that influence entrepreneurs’ choice between using networks versus market methods. In this study, we propose a contingent model of network utilization when approaching initial investors, based on the dimensions of human capital of the entrepreneurs. We test this model with primary field survey data from 226 new high–tech ventures in Singapore and Beijing. The results show that high occupational status and relevant industrial work experience are positively associated with the entrepreneurs’ propensity to utilize existing networks by enhancing the resourcefulness of their network ties (social capital); however, such influences are alleviated by entrepreneurs’ marketing or managerial experience, which increases the entrepreneurs’ ability to interact with strangers (an aspect of social competence).
The Collaborative Network Orientation: Achieving Business Success through Collaborative Relationships
Authors: Sorenson Ritch L. , Folker Cathleen A. , Brigham Keith H.
Published: June 2008

This study presents a theoretical concept called the collaborative network orientation (CNO) and tests it using a sample of male and female small business owners. The CNO is based on (1) research that indicates female managers prefer to organize in cooperative network relationships and (2) conflict theory that indicates collaboration is preferred for both building relationships and achieving goals. Empirical tests revealed that female owners had a stronger preference for a CNO. A CNO was associated with business success for all owners, but it was significantly more positively associated with success for male business owners.
Entrepreneurial Orientation, Learning Orientation, and Firm Performance
Authors: Wang Catherine L.
Published: June 2008

Entrepreneurial orientation (EO) is a key ingredient for firm success. Nonetheless, an important message from past findings is that simply examining the direct effect of EO on firm performance provides an incomplete picture. Prior studies examined various internal and external factors that influence the EO–performance relationship. However, learning orientation (LO) has been a missing link in the examination of the relationship. Using data from 213 medium–to–large UK firms, this study finds that LO mediates the EO–performance relationship, and the EO–LO–performance link is stronger for prospectors than analyzers. The findings indicate that LO must be in place to maximize the effect of EO on performance, and that LO is an important dimension, along with EO, to distinguish prospectors from analyzers.
The Role of Perceived Relational Support in Entrepreneur–Customer Dyads
Authors: De Clercq Dirk , Rangarajan Deva
Published: June 2008

Drawing from social exchange theory and the marketing literature, we posit that entrepreneurs’ commitment to and satisfaction with a customer depends on the extent to which they believe the customer is willing to provide strong support to entrepreneurs in their role as suppliers. We tested the hypotheses among 217 entrepreneurs in a Western European country and found that entrepreneurs’ perceptions of relational support relate positively to their commitment to and satisfaction with the customer. In turn, the reliability and quality of the exchanges that took place between entrepreneurs and the customer affected their perceptions of relational support, as well as their attitudes through perceived relational support. We thus identify a key mechanism that explains relationship outcomes in entrepreneur–customer dyads. We discuss the implications and limitations of our findings and provide directions for further research.
Perceived Institutional Ambiguity and the Choice of Organizational Form in Social Entrepreneurial Ventures
Authors: Townsend David M. , Hart Timothy A.
Published: June 2008

Social entrepreneurship (SE) is emerging as a common approach to meeting social needs. However, SE founders appear to be organizing under both for–profit and nonprofit organizational forms to engage in essentially the same activities. We investigate this lack of consistency regarding the choice of organizational form by examining two possible explanations: a difference in motivational goals among social entrepreneurs or perceived ambiguity regarding trends in core dimensions of the institutional environment. Overall, we argue that founder perceptions of an ambiguous institutional environment are leading to the variance in choice of organizational form for SE ventures. Both theoretical and practical directions for future research are discussed as well.
Portfolio Entrepreneurship: Habitual and Novice Founders, New Entry, and Mode of Organizing
Authors: Wiklund Johan , Shepherd Dean A.
Published: June 2008

With the purpose of advancing our understanding of portfolio entrepreneurship, we separate the act of entrepreneurship (new entry) from its mode or organizing (internal vs. independent organization). Analyzing a cohort of 2,253 novice and habitual business founders, we find that portfolio entrepreneurship is a common phenomenon and that the majority of portfolio entrepreneurs use the internal mode of organizing. Whether or not business founders subsequently pursue portfolio entrepreneurship is explained by their human capital (education and start–up experience) and social capital (business networks and links with government support agencies). Further, novice entrepreneurs are more likely to organize portfolio entrepreneurship within their existing firms while habitual entrepreneurs more often organize subsequent acts of portfolio entrepreneurship by creating another new independent organization. Implications for entrepreneurship research are discussed.
Effectuation and Over–Trust: Debating Goel and Karri
Authors: Sarasvathy Saras , Dew Nicholas
Published: June 2008

In their article on entrepreneurship, effectuation, and over–trust, Goel and Karri suggest relationships between effectuation, over–trust, and certain psychological characteristics of entrepreneurs. In this response we debate their article. Goel and Karri are correct in claiming that effectuation supposes over–trust. However, we argue that effectual logic works in a different way than they presented because it neither predicts nor assumes trust. Goel and Karri's article also draws attention to the behavioral assumptions underlying constructs such as over–(under) trust. Our suggestion is that effectuation is based on alternative behavioral assumptions that open up interesting avenues for future research in entrepreneurship.