Current Risk Level Research Articles

Safety risk perception in construction companies in the Pacific Northwest of the USA

Unsafe worker actions contribute greatly to the frequency and severity of construction injuries. Recently, contractors have expressed concern with the high rate of injuries that occur when workers violate company safety policies. To enhance knowledge associated with this topic the following four objectives were targeted: (1) quantifying the current level of safety risk as perceived by construction workers; (2) quantifying the risk tolerance of workers and managers; (3) comparing the risk perceptions and tolerance of workers with managers; and (4) identifying factors that may affect one’s risk tolerance. Fifty‐one risk perceptions were gathered through interviews with managers and workers of nine different construction firms in the Pacific Northwest region of the United States. The results indicate that the level of current perceived risk is approximately five times higher than the tolerable risk value, workers are most dissatisfied with the frequency of high severity injuries, and there is a statistically significant difference in the risk tolerance between workers and managers. The findings presented can be used by project managers to increase awareness of risk tolerances, current areas where workers feel improvement is most needed, and for goal setting.

Olfactory recognition of predators by nocturnal lizards: safety outweighs thermal benefits

Many prey species are faced with multiple predators that differ in the degree of danger posed. The threat-sensitive predator avoidance hypothesis predicts that prey should assess the degree of threat posed by different predators and match their behavior according to current levels of risk. To test this prediction, we compared the behavioral responses of nocturnal velvet geckos, Oedura lesueurii, to chemicals from 2 snakes that pose different threats: the dangerous broad-headed snake Hoplocephalus bungaroides that eats geckos and the less dangerous small-eyed snake Cryptophis nigrescens that eats skinks (i.e., does not consume geckos). We also tested whether predator avoidance by prey was modulated by thermal costs associated with retreat-site selection. In both the presence and absence of thermal costs, velvet geckos avoided crevices scented by both dangerous and less dangerous snake species. When given the choice between a crevice scented by a broad-headed snake and a crevice scented by a small-eyed snake, most geckos avoided either retreat site. These results suggest that velvet geckos treat both snake predators as equally dangerous. To further explore these results, we quantified patterns of retreat-site selection by free-living velvet geckos on 2 sandstone plateaux. As in the laboratory, velvet geckos avoided thermally suitable rocks previously used by both snake species. Hence, a gecko's choice of retreat site is influenced by the presence of snake chemicals but is independent of thermal costs or the level of danger posed by the predator. To minimize their risk of predation, geckos may use a simple rule of thumb: “all snakes are dangerous.”

National cardiovascular prevention should be based on absolute disease risks, not levels of risk factors

It has been shown that the prevention of multicausal diseases such as heart attack (at an individual level) should be guided by absolute risks rather than by the level of risk factors. Here, we show that an analogous argument should form the basis of population-level prevention. Estimates of age- and sex-specific means and standard deviations for systolic blood pressures and blood cholesterol concentrations and for deaths assigned to all vascular causes in 2002 were obtained from the World Health Organization for 25 current member states of the European Union, for the ages 30-69 years. Predicted effects of 5 mmHg reductions in mean systolic blood pressures and 0.5 mmol l(-1) reductions in mean total blood cholesterol concentrations on deaths and years of life lost (YLL) per 100,000 person-years from vascular diseases were modelled using proportional risk coefficients from meta-analyses of cohort studies and randomized controlled trials. Potential absolute benefits were strongly positively associated with current levels of absolute mortality risk: in the case of systolic blood pressure, predicted vascular deaths averted in the highest risk populations (Romania, Bulgaria) were over five times higher than in the lowest risk populations (Spain, France). Potential benefits were only weakly related to existing levels of the risk factor of interest. High-risk populations should give the highest priority to achieving favourable shifts in all modifiable risk factors. Irrespective of the level of any particular risk factor, the rewards will be greatest in these populations.

The effect of prior experience on a prey’s current perceived risk

The prior experience of prey may influence how they assess the level of predation risk associated with an information source. Here, I present the results from a set of experiments that demonstrate how the prior experience of green frog (Rana clamitans) tadpoles can influence their risk assessment during exposure to the chemical cue of predatory larval dragonflies (Anax spp.) consuming conspecific tadpoles. At the short-term scale, green frog tadpoles perceived a higher level of risk when consecutive cue exposures overlapped, but only when the total chemical cue concentration was weak. Weaker chemical cue concentrations may be less reliable than stronger cue concentrations, and overlapping cue exposures may increase the degree of certainty that tadpoles have in their perceived risk. When consecutive cue exposures did not overlap, tadpoles assessed the risk associated with each cue exposure independently. Predator-conditioned tadpoles responded longer during exposure to the Anax chemical cue than nonconditioned tadpoles, which suggests that a tadpole's long-term experience eventually does influence its risk assessment. In general, the results suggest that a prey's prior experience may influence its current perceived risk by influencing either the degree of certainty in or the level of its perceived risk. Understanding how the prior experience of prey influences their current risk assessment requires that the rate of decay of the value of prior experience should be identified at two timescales as an indicator of the current level of predation risk.

Antipredator behaviour of naïve Arctic charr young in the presence of predator odours and conspecific alarm cues

Abstract – We investigated how Arctic charr young respond behaviourally to olfactory cues from skin‐damaged conspecifics, charr‐fed pikeperch, and the combination of food‐deprived pikeperch and skin‐damaged conspecific cues in a two‐channel Y‐maze fluviarium test arena. Significant antipredator responses were found to skin‐damaged conspecifics in three behavioural traits, to charr‐fed pikeperch in two traits and to the combination of pikeperch and skin‐damaged conspecific cues in all six behaviours investigated. The combination of predator and conspecific cues significantly increased spatial avoidance and cautiousness to approach the source of scent compared with odours from charr‐fed predators. The results suggest that damage‐released alarm cues exist in charr, and they strengthen the antipredator responses in conspecifics. As the charr used different behaviours and levels of response in the presence of different cues, they seem to have sophisticated skills to distinguish between different odour combinations and be able to adjust their behaviour according to the current predation risk level.

Prion reduction filters

In today's Lancet, Luisa Gregori and colleagues1 show that an affinity-resin column is capable of removing infectivity associated with endogenous prions from leucofiltered whole blood in a scrapie-infected hamster model. This builds on previous work by this group2,3 and others4,5 showing that prion reduction via filtration could reduce the risk of transmitting variant Creutzfeldt-Jakob disease (vCJD) by blood transfusion. What is the current level of risk and how effective are these devices likely to be?

A/H5N1 in the European Union: current levels of risk to humans, and responding to human cases and outbreaks

This issue of Eurosurveillance includes a report by Georgia Spala et al of the investigation of a suspected outbreak in Greece of avian influenza (A/H5N1 virus infection) in humans [1]. This took place in the early spring of 2006 when infected wild birds appeared in many European Union (EU) countries. There were confirmed infections in birds in Greece, but after careful investigation, no human infections were found. However, the massive investigation and control that had to take place around the infections and deaths in the outbreak in Turkey in December 2005 and January 2006 [2] is a reminder of what could have been in Greece or other EU countries.

Range-wide Yangtze freshwater dolphin expedition: The last chance to see Baiji?

Background, Aim and Scope There are two species of fresh water cetaceans surviving in the Yangtze River system in China: Baiji (Lipotes vexillifer) and Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis). As a result of the expansion of human activities on the river, their distribution ranges appear to be decreasing and in the case of the Baiji, are even being restricted to several sections. The Baiji is the world’s most critically endangered cetacean species with a population estimated at only a few tens of individuals. The Yangtze finless porpoise is the world’s only freshwater-adapted population of the species, and it has been estimated that only around 1,000 individuals remain in the river system. In order to prevent the extinction of Baiji and a sharp decline in the abundance of the porpoise, in situ conservation (i.e. in the river) and two ex situ conservation (i.e. in semi-natural reserves and in captivity) strategies were proposed and have been implemented since the early 1990s. In view of both the severely endangered status of the animals and the severely degraded conditions of their habitats, the feasibility and actual status of these two strategies are raised for discussion.

Does Temporal Variation in Predation Risk Influence the Intensity of Antipredator Responses? A Test of the Risk Allocation Hypothesis

AbstractTemporal variation in predation risk may fundamentally influence antipredator responses of prey animals. To maximize lifetime fitness, prey must be able to optimize energy gain and minimize predation risk, and responses to current levels of risk may be influenced by background levels of risk. A ‘risk allocation’ model has recently been proposed to predict the intensity of antipredator responses that should occur as predation risk varies over time. Prey animals from high‐risk environments should respond to predators with relatively low intensities of antipredator behaviour because long periods of antipredator behaviour may result in unacceptable decreases in levels of foraging activity. Moreover, animals that are under frequent risk should devote more energy to foraging during brief pulses of safety compared with animals under infrequent attack. In this study, we experimentally tested the risk allocation hypothesis. We exposed juvenile rainbow trout, Oncorhynchus mykiss, to three levels of risk (high, moderate and low) crossed with two levels of temporal variation (exposed to risk three times a day and once a day). In accordance with the model, we found that trout exposed to risky situations more frequently responded with significantly less intense antipredator behaviour than trout exposed to risk infrequently. The intensity of response of trout exposed to moderate risk three times a day decreased to levels similar to situations of no risk. However, in contrast to the second prediction of the model, animals under frequent risk were not more active during periods of safety compared with animals under infrequent risk. Although behaviour in the face of predation risk was dependent on the broader temporal context in which risk varied, the specific predictions of the risk allocation model were only partly supported.

High-grade prostatic intraepithelial neoplasia in needle biopsy as risk factor for detection of adenocarcinoma: Current level of risk in screening population

Objectives To assess the current incidence of prostate carcinoma detection in serial biopsies in a prostate-specific antigen-based screening population after a diagnosis of isolated high-grade prostatic intraepithelial neoplasia (HG-PIN) in needle biopsy tissue. Methods We retrospectively identified 190 men with a diagnosis of isolated HG-PIN in needle biopsy tissue. Most men (86%) were diagnosed from 1996 to 2000. Logistic regression analysis was used to predict the presence of carcinoma in these 190 men and in a control group of 1677 men with only benign prostatic tissue in needle biopsy tissue. Results The cumulative risk of detection of carcinoma on serial sextant follow-up biopsies was 30.5% for those with isolated HG-PIN compared with 26.2% for the control group ( P = 0.2). Patient age ( P = 0.03) and serum prostate-specific antigen level ( P = 0.02) were significantly linked to the risk of cancer detection, but suspicious digital rectal examination findings ( P = 0.1), the presence of HG-PIN ( P = 0.2), and the histologic attributes of PIN were not (all with nonsignificant P values). HG-PIN found on the first repeat biopsy was associated with a 41% risk of subsequent detection of carcinoma compared with an 18% risk if benign prostatic tissue was found on the first repeat biopsy ( P = 0.01). Conclusions The results of our study have shown that the current level of risk for the detection of prostate carcinoma in a screened population is 30.5% after a diagnosis of isolated HG-PIN in a needle biopsy. This risk level is lower than the previously reported risk of 33% to 50%. HG-PIN is a risk factor for carcinoma detection only when found on consecutive sextant biopsies. The data presented here should prompt reconsideration of repeat biopsy strategies for HG-PIN, and re-evaluation of the absolute necessity of repeat biopsy for all patients with HG-PIN.

Wall Lizards Modulate Refuge Use through Continuous Assessment of Predation Risk Level

AbstractPrey species might use several possible ways to assess predation risk when encountering a predator. Animals may consider the risk level estimated in a first encounter to remain unchanged across subsequent encounters (fixed risk response), or they may update and change their responses across encounters in accordance with short‐term changes in risk levels (flexible risk response). We examined in the field how wall lizards assess risk level by analyzing time spent in refuges after simulated predator attacks. We first examined how risk was assessed when multiple consecutive sources of risk were present simultaneously. The results suggest that wall lizards assess risk based on multiple cues, such as approach speed, directness, and persistence (measured as the distance of the predator to their refuge after an attack). When risk was high lizards remained longer in their refuges. The first decision to appear partly from the refuge depended on both approach speed and persistence, whereas the decision to emerge completely depended only on persistence and not on approach speed. This suggests that wall lizards update information on predator threat and adjusted their emergence accordingly. In a second experiment, we analyzed how short‐term changes in risk level of successive attacks affected refuge use. Successive emergence times varied as a function of current risk level of each repeated attack, independently of the risk level of previous attacks. This indicated that lizards could track short‐term changes in risk level through time and modify their initial responses when required. Fine adjustments of refuge use may help lizards to minimize costs of refuge use in unfavorable and variable environments where antipredatory responses are costly.

Wall lizards combine chemical and visual cues of ambush snake predators to avoid overestimating risk inside refuges

The threat sensitivity hypothesis assumes that multiple cues from a predator should contribute in an additive way to determine the degree of risk-sensitive behaviour. The ability to use multiple cues in assessing the current level of predation risk should be especially important to prey exposed to multiple predators. Wall lizards, Podarcis muralis, respond to predatory attacks from birds or mammals by hiding inside rock crevices, where they may encounter another predator, the smooth snake, Coronella austriaca. We investigated in the laboratory whether chemical cues may be important to wall lizards for detection of snakes. The greater tongue-flick rate and shorter latency to first tongue-flick in response to predator scents indicated that lizards were able to detect the snakes' chemical cues. We also investigated the use of different predatory cues by lizards when detecting the presence of snakes within refuges. We simulated successive predator attacks and compared the propensity of lizards to enter the refuge and time spent within it for predator-free refuges, refuges containing either only visual or chemical cues of a snake, or a combination of these. The antipredatory response of lizards was greater when they were exposed to both visual and chemical cues than when only one cue was presented, supporting the threat sensitivity hypothesis. This ability may improve the accuracy of assessments of the current level of predation risk inside the refuge. It could be especially important in allowing lizards to cope with threats posed by two types of predators requiring conflicting prey defences.

Stakeholder perceptions of risk in motor sport

Problem: Stakeholders have different reasons for their interest in the regulation of motor racing. These reasons include the provision of, for example, safety for drivers, excitement for spectators, financial success for racing teams, and a positive environment for sponsors' products and services. The acceptability/unacceptability of current risk levels in motor racing depends on these stakeholders' perceptions of risk, within the sport. Method: This study assessed the risk perceptions and preferences of stakeholders through the use of structured interviews. Comparative data on fatal accident rates (FARs) in sport were obtained from published data. The number and type of vehicle incidents during competition were obtained from the circuit marshals' incident reports and post-race vehicle damage was assessed by visual inspection. Discussion: Two hundred and three stakeholders, defined as spectators (49), race officials (69), race teams (63), and safety managers (22) were interviewed during open-wheel and closed-wheel motor racing competitions. Significant differences ( P<.05) were observed between stakeholders for the relative risk perception scores across five sports; however, their rank ordering of the relative risk perception scores were similar and consistent with FARs for these sports. Spectators demonstrated a reverse affiliation bias effect by overstating the relative risks of motor racing, compared to other stakeholders. All stakeholders perceived the relative risks associated with open-wheel racing to be significantly greater than closed-wheel racing and the relative risks associated with standing race starts to be significantly greater than rolling race starts. However, all stakeholders demonstrated a domain effect, and spectators and race officials also demonstrated cognitive dissonance, in their expressed preferences for the type of motor race starts. Nineteen of the 21 race team managers nominated just three motor racing circuits and 17 team managers nominated “run-off” or “drop-off” track features as presenting the greatest risk to drivers. Impact on industry: The results obtained confirm the complexities faced by governing bodies when setting acceptable levels of risk within professional sports regulations.

Evaluating the effectiveness of risk-reduction strategies for consumer chemical products.

Communication about risks offers a voluntary approach to reducing exposure to pollutants. Its adequacy depends on its impact on behavior. Estimating those impacts first requires characterizing current activities and their associated risk levels, and then predicting the effectiveness of risk-reduction strategies. Characterizing the risks from chemical consumer products requires knowledge of both the physical and the behavioral processes that influence exposures. This article presents an integrated approach that combines consumer interviews, users' beliefs and behaviors, and quantitative exposure modeling. This model was demonstrated in the context of consumer exposure to a methylene chloride-based paint stripper, showing how it could be used to evaluate current levels of risk and predict the effectiveness of proposed voluntary risk-reduction strategies.

Developing a Substance Abuse Relapse Screening Questionnaire for Adults on Intensive Probation

The Relapse Screening Questionnaire (RSQ) is being developed to identify high risk situations that may lead to relapse among clients on probation, identify current risk levels of clients and orient clients toward cognitive-based therapy techniques utilized by supervising probation officers to prevent relapse. The instrument was piloted on 27 adult men with a history of drug abuse sentenced to intensive probation in a small southwestern U.S. city. Inter-item reliability on the instrument was .90. Subjects identified as at severe risk by the instrument were more likely to relapse than those not so identified. None of the subjects identified in the three lower risk categories by the screening instrument relapsed during the two-month period following the pilot study, while 33% of the subjects identified by the instrument as at severe risk relapsed in the two months following the pilot. Chi-square analysis indicated this was significant (.10). The theory upon which the RSQ is based, the pilot data collected and the potential utility of such an instrument for local probation and parole agencies is described.

Making Gas Turbines Safer

This article presents recommendations resulting from a study of the safety of enclosures at the Teeside combined-cycle gas turbine (CCGT) power plant that may help other plant operators assess and reduce the risk of explosions. Many of the gas turbines in CCGT plants like Teeside are housed in acoustic chambers to reduce noise and permit turbine cooling by ventilation. The Eutech study at Teeside showed that the substantial number of pipes and flanges in a gas turbine enclosure, combined with high pressures, presents the hazard of explosion in case of gas leaks. The hazard analysis of Teeside was carried out to develop several fault trees to quantify the current level of risk to an operator from an explosion inside the enclosure. Eutech made several recommendations to Enron to improve safety at Teeside. They were: increasing the number of gas detectors, locating them more closely to points where leaked gas would collect, and improving the detectors' reliability by examining their potential failure modes.

Climate change impacts on the reliability of hydroelectric energy production

This paper presents the assessment of climate change impacts on some critical water management issues such as reservoir storage and hydroelectric production. Two equilibrium scenarios (UK Meteorological Office High Resolution model, UKHI and Canadian Climate Centre model, CCC) referring to years 2020, 2050 and 2100 and one transient scenario (UK High Resolution Transient output, UKTR) referring to years 2032 and 2080 were applied to represent both “greenhouse” warming and induced changes in precipitation and potential evapotranspiration. By using these scenarios, the sensitivity of the risk associated with the annual hydroelectric energy production of a large multipurpose reservoir in northern Greece has been evaluated under conditions of altered runoff. It is shown that the operational characteristics of the reservoir designed and operated under current climatic conditions are, in general, affected by the climate change scenarios examined. Increases of the risks associated with the annual quantities of energy production have been observed, particularly under the UKHI and die UKTR scenarios. For the UKHI scenario, increases of reservoir storage volumes of up to about 12% and 38% are required in order to maintain at current risk levels the minimum and mean annual energy yields respectively, while for the UKTR scenario the corresponding increases are estimated to be about 25% and 50%.

Application of ALARP to the design of the BP Andrew platform against smoke and gas ingress and gas explosion

In the UK, it is a legal requirement for a safety case to be produced for each offshore installation. A safety case involves a process called ‘formal safety assessment’ in which all hazards and risk to personnel on the platform are identified and quantified. The operator or designer of the installation is required to demonstrate that the risk to personnel is below a level which is deemed to be unacceptable, and in any case, reduced to a level which is as low as reasonably practicable (ALARP). In an existing facility, any risk reduction measures can be judged to be ‘reasonably practicable’ by balancing the cost of implementing the measure and the benefit in terms of risk reduction set against a baseline risk level (i.e. the current risk level of the facility). In the design of new facilities, there is no pre-existing baseline risk level. The demonstration of the application of ALARP is through the process of design. This paper describes the work undertaken during the design of the BP Andrew platform to assess and reduce the risk of temporary refuge (TR) impairment due to gas explosion and smoke and gas ingress. The process of platform design and risk analysis was integrated in the Andrew Project; safety technologists at BP using state-of-the-art quantification methods were part of the engineering design team at Brown & Root. This allowed the Project to identify practical changes in their design which could reduce risk significantly without incurring cost or schedule penalties. In fact, the project was able to identify design changes which reduce both the risk of TR impairment and cost of the facility, i.e. a negative cost measure! Two examples are included to demonstrate how the principle of ALARP was achieved by two different routes: (a) the platform was designed against a worst-case event, thus achieving the lowest possible risk, and (b) the risk of TR impairment of available practicable design options was accurately quantified and understood and the design option with the lowest risk was chosen. The project was able to demonstrate a final TR impairment of less than 4 × 10 −5 per year at the end of the design.

Acquired Immunodeficiency Syndrome/Human Immunodeficiency Virus Risk Behavior Among Gay Men in Small Cities

Most research on acquired immunodeficiency syndrome has been conducted in several of the country's largest cities, and little is known about the current level of human immunodeficiency virus risk taking among gay men in other geographical areas. The purpose of this study was to determine the frequency of risk behavior practices among gay men in smaller communities. A large sample of men who patronized gay bars in 16 small and moderate-size cities drawn from six states in four different regions of the country was surveyed to determine the frequency of high-risk behavior and factors influencing risk taking. Eighty-five percent of men in all cities' bars completed all survey measures. The community samples were 1991 men; mean age, 31.3 years; mean education, 10.6 years; 90% were white and 10% were of other ethnicities. All participants provided detailed information on their sexual behavior practices over the preceding 2 months and completed measures assessing their perceived peer norms concerning safer sex practices and risk avoidance, intentions to avoid risk, personal risk estimation, acquired immunodeficiency syndrome risk knowledge, perceived threat of acquired immunodeficiency syndrome/human immunodeficiency virus, and serostatus testing history. High-risk patterns were still common among gay men in these smaller cities; nearly one third of all men had engaged in unprotected anal intercourse an average of eight times in the past 2 months, usually outside monogamous relationships. High-risk behavior was most strongly associated with beliefs that safer sex practices would not be well accepted by peers, weak intentions to use condoms, underestimation of personal vulnerability to the acquired immunodeficiency syndrome, younger age, and higher levels of overall sexual activity. Nine percent of men tested said they were seropositive. Growing human immunodeficiency virus prevalence and continued high rates of risk behavior indicate that a new "front line" for human immunodeficiency virus prevention among homosexually active men has shifted to the country's smaller cities. Community prevention efforts in these areas are urgently needed to avert sharp increases in future human immunodeficiency virus infections in this population.

Risk reduction by drug users with regard to HIV infection

Prevalence levels of HIV infection among injecting drug users rapidly reached 50% or more in several cities worldwide (e.g. New York, Edinburgh, Bangkok); other cities have seen sustained lower levels of infection, and in some cases declining incidence. Research evidence indicates that many long term drug injectors now have high levels of HIV transmission awareness, and that they are able to change their behaviour to reduce risk of infection. Public health interventions (bleach, syringe distribution) and drug treatment (methadone) enable behavioural change. Risk reduction for needle and syringe sharing is more common than for sexual behaviour. Condom use remains low and selective. Despite changes in behaviour, current residual levels of risk probably remain high enough to ensure continued spread of infection. Improved prevention efforts must focus on initiating and sustaining change, sexual behaviour, and methods for reaching harder-to-reach populations (women, younger injectors, non-urban populations, pr...