Safety In Numbers Research Articles

Host density increases parasite recruitment but decreases host risk in a snail-trematode system.

Most species aggregate in local patches. High host density in patches increases contact rate between hosts and parasites, increasing parasite transmission success. At the same time, for environmentally transmitted parasites, high host density can decrease infection risk to individual hosts, because infective stages are divided among all hosts in a patch, leading to safety in numbers. We tested these predictions using the California horn snail, Cerithideopsis californica (=Cerithidea californica), which is the first intermediate host for at least 19 digenean trematode species in California estuaries. Snails become infected by ingesting trematode eggs or through penetration by free-swimming miracidia that hatch from trematode eggs deposited with final-host (bird or mammal) feces. This complex life cycle decouples infective-stage production from transmission, raising the possibility of an inverse relationship between host density and infection risk at local scales. In a field survey, higher snail density was associated with increased trematode (infected snail) density, but decreased trematode prevalence, consistent with either safety in numbers, parasitic castration, or both. To determine the extent to which safety in numbers drove the negative snail-density-trematode-prevalence association, we manipulated uninfected snail density in 83 cages at eight sites within Carpinteria Salt Marsh (California, USA). At each site, we quantified snail density and used data on final-host (bird and raccoon) distributions to control for between-site variation in infective-stage supply. After three months, overall trematode infections per cage increased with snail biomass density. For egg-transmitted trematodes, per-snail infection risk decreased with snail biomass density in the cage and surrounding area, whereas per-snail infection risk did not decrease for miracidium-transmitted trematodes. Furthermore, both trematode recruitment and infection risk increased with infective-stage input, but this was significant only for miracidium-transmitted species. A model parameterized with our experimental results and snail densities from 524 field transects estimated that safety in numbers, when combined with patchy host density, halved per capita infection risk in this snail population. We conclude that, depending on transmission mode, host density can enhance parasite recruitment and reduce per capita infection risk.

Safety in Numbers: Data From the Duke Pediatric Residency Safety Council (Platform Presentation)

The ACGME Clinical Learning Environment Review focuses on six areas of trainee working and learning environments, including safety and quality improvement (QI). Recent graduates report dissatisfaction with exposure in these areas, with most training didactic rather than practical. We describe a resident-run safety council as a means to engage residents as active drivers of safety and QI.

Estimating the safety benefit of separated cycling infrastructure adjusted for behavioral adaptation among drivers; an application of agent-based modelling

Separated cycling infrastructure is a key strategy employed by urban and transport planners to reduce car vs cyclist crashes.We constructed an agent-based model (ABM) to explore the potential effects of introducing progressively greater levels of saturation (e.g., more kms) of separated cycling infrastructure into a transport network in which drivers also demonstrated behavioral adaptation in response to increased exposure to cyclists as suggested by the safety in numbers (SiN) theory.The findings highlight that if behavioral adaptation among drivers is assumed to be a strong mechanism underpinning cyclist safety, the introduction of low levels of separated cycling infrastructure across a network (e.g., few kms) may provide little or no reduction in car vs cyclist crashes. This is due to the countervailing effects that separated infrastructure may have on drivers’ exposure to cyclists; a fundamental contributor to the concept of behavioral adaptation.This study demonstrates the utility of ABMs to explicitly define and model candidate behavioral mechanisms associated with cyclist and vehicle interaction when estimating the interaction of infrastructure and behavioral mechanisms proposed to underlie cyclist safety. Practically, it suggests that greater saturation of separated cycling infrastructure across transport networks may be required to reduce overall car vs cyclist crashes in circumstances where behavioral adaptation is also a strong mechanism contributing to cyclist safety.

Safety in numbers? Gastric cancer survival varies with total retrieved lymph nodes.

4058 Background: Recently published AJCC 8thTNM-staging guidelines recommend a minimum of 16 lymph nodes be assessed in gastric cancer surgery with more lymph nodes ( 30) being desirable. However, the independent effects of greater numbers of lymph nodes excised on the overall survival of patients with gastric adenocarcinoma are understudied. Methods: National Cancer Database (NCDB) was reviewed from 2010 to 2014 for patients who underwent potentially curative surgery for gastric adenocarcinoma. Patients with zero or unknown number of harvested lymph nodes were excluded, as were those with metastatic or in-situ disease, or who received neoadjuvant chemo- or radiotherapy. Cox proportional hazards modeling was used for multivariate survival analysis. Results: Of the 12,507 patients who met selection criteria, 4,880 (39.0%) were female. The median age was 69 years [IQR: 59-77]. Median number of lymph nodes examined for each clinical T and N-stage is provided in the table. Overall, 51.0% of patients had < 16 lymph nodes examined. After adjusting for clinical T and N-stages, sex, age, tumor size, grade, facility type, receipt of adjuvant chemotherapy, resection type and race, and compared to patients with < 16 nodes examined, the hazard ratios for death in patients with 16-29, 30-44 and ≥45 examined lymph nodes were 0.87 (95% CI = 0.82-0.93), 0.79 (95% CI = 0.71-0.88) and 0.68 (95% CI = 0.56-0.83), respectively. Conclusions: Total lymph node count is an important independent predictor of overall survival in resectable gastric cancer, with an increased number of excised lymph nodes being associated with progressively decreased risk of death. These findings support the latest AJCC guidelines that higher number of lymph node retrieval is desirable. The recommended oncologic standard for at least 16 nodes to be assessed pathologically is not attained in more than half of upfront gastric resections performed for cancer. [Table: see text]

Self-protection promotes altruism

Self-protection tendencies allowed our human ancestors to survive and thrive. In three experiments, we find that individuals who have a salient self-protection motive are more altruistic to others, such as by helping them out or offering them more money in the dictator game paradigm. Self-protecting individuals desire to “bind together” as there is “safety in numbers”, and being altruistic to others should be one (but not the only) way to achieve this goal. Consistent with this reasoning, we find across three behavioral experiments using both non-monetary (Experiment 1) and monetary altruistic contexts (Experiments 2–3) that self-protecting individuals are more altruistic when the altruism is not anonymous (Experiment 1) and when they have the reasonable expectation of future interaction with the recipient (Experiment 2), both of which are situations that should increase affiliation. The effect attenuates when altruism does not help self-protecting individuals, such as when money is donated to impersonal organizations rather than individuals (Experiment 3). We finally discuss the theoretical contributions as well as limitations of our work.

SAFETY IN NUMBERS

Gah‐Yi Ban explains how inventory theory combined with Big Data could help address the problem of global waste

Experience buffers extrinsic mortality in a group‐living bird species

Extrinsic mortality has a strong impact on the evolution of life‐histories, prey morphology and behavioural adaptations, but for many animals the causes of mortality are poorly understood. Predation is an important driver of extrinsic mortality and mobile animals form groups in response to increased predation risk. Furthermore, in many species juveniles suffer higher mortality than older individuals, which may reflect a lower phenotypic quality, lower competitiveness, or a lack of antipredator or foraging skills. Here we assessed the causes of mortality for 371 radio tagged Siberian jays. This sedentary bird species lives in family groups that contain a breeding pair as well as related and unrelated non‐breeders. Ninety‐five percent of death were due to predation (n = 59 out of 62 individuals) and most individuals were killed by Accipiter hawks. Multivariate Cox proportional hazards models showed that non‐breeders had a lower survival than breeders, but only in territories in managed forest with little visual cover. Examining breeders, only sex influenced survival with males having a lower survival than females. For non‐breeders, juveniles had lower survival than older non‐breeders, and those on managed territories had lower survival than those on unmanaged territories. Additionally, a low feather quality reduced the survival probability of non‐breeders only. Thus, living on managed territories and having a low feature quality affected only non‐breeders, particularly juveniles. These findings add to previous research demonstrating that juvenile Siberian jays acquire critical antipredator skills from experienced group members. Thus, experience can buffer extrinsic mortality, highlighting that group living not only provides safety in numbers, but also provide social opportunities to learn critical life‐skills.

On the effect of networks of cycle-tracks on the risk of cycling. The case of Seville

We analyze the evolution of the risk of cycling in Seville before and after the implementation of a network of segregated cycle tracks in the city. Specifically, we study the evolution of the risk for cyclists of being involved in a collision with a motor vehicle, using data reported by the traffic police along the period 2000–2013, i.e. seven years before and after the network was built. A sudden drop of such risk was observed after the implementation of the network of bikeways. We study, through a multilinear regression analysis, the evolution of the risk by means of explanatory variables representing changes in the built environment, specifically the length of the bikeways and a stepwise jump variable taking the values 0/1 before/after the network was implemented. We found that this last variable has a high value as explanatory variable, even higher than the length of the network, thus suggesting that networking the bikeways has a substantial effect on cycling safety by itself and beyond the mere increase in the length of the bikeways. We also analyze safety in numbers through a non-linear regression analysis. Our results fully agree qualitatively and quantitatively with the results previously reported by Jacobsen (2003), thus providing an independent confirmation of Jacobsen's results. Finally, the mutual causal relationships between the increase in safety, the increase in the number of cyclists and the presence of the network of bikeways are discussed.

796: Group prenatal care for diabetes: safety in numbers?

796: Group prenatal care for diabetes: safety in numbers?

The Majority‐Minority Divide in Attitudes toward Internal Migration: Evidence from Mumbai

AbstractRapid urbanization is among the major processes affecting the developing world. The influx of migrants to cities frequently provokes antagonism on the part of long‐term residents, manifested in labor market discrimination, political nativism, and violence. We implemented a novel, face‐to‐face survey experiment on a representative sample of Mumbai's population to elucidate the causes of anti‐migrant hostility. Our findings point to the centrality of material self‐interest in the formation of native attitudes. Dominant group members fail to heed migrants' ethnic attributes, yet for minority group respondents, considerations of ethnicity and economic threat crosscut. We introduce a new political mechanism to explain this divergence. Minority communities facing persistent discrimination view in‐migration by coethnics as a means of enlarging their demographic and electoral base, thereby achieving “safety in numbers.” Our article sheds light on the drivers of preferences over internal migration. It also contributes insights to the international immigration literature and to policy debates over urban expansion.

Whatever happened to safety in numbers?

Whatever happened to safety in numbers?

Evaluating the impact of bike network indicators on cyclist safety using macro-level collision prediction models

Many cities worldwide are recognizing the important role that cycling plays in creating green and livable communities. However, vulnerable road users such as cyclists are usually subjected to an elevated level of injury risk which discourages many road users to cycle. This paper studies cyclist-vehicle collisions at 134 traffic analysis zones in the city of Vancouver to assess the impact of bike network structure on cyclist safety. Several network indicators were developed using Graph theory and their effect on cyclist safety was investigated. The indicators included measures of connectivity, directness, and topography of the bike network. The study developed several macro-level (zonal) collision prediction models that explicitly incorporated bike network indicators as explanatory variables. As well, the models incorporated the actual cyclist exposure (bike kilometers travelled) as opposed to relying on proxies such as population or bike network length. The macro-level collision prediction models were developed using generalized linear regression and full Bayesian techniques, with and without spatial effects. The models showed that cyclist collisions were positively associated with bike and vehicle exposure. The exponents of the exposure variables were less than one which supports the “safety in numbers” hypothesis. Moreover, the models showed positive associations between cyclist collisions and the bike network connectivity and linearity indicators. In contrast, negative associations were found between cyclist collisions and the bike network continuity and topography indicators. The spatial effects were statistically significant in all of the developed models.

Safety in Numbers: Progressive Implementation of a Robotics Program in an Academic Surgical Oncology Practice.

Background Robotic-assisted surgery has potential benefits over laparoscopy yet little has been published on the integration of this platform into complex surgical oncology. We describe the outcomes associated with integration of robotics into a large surgical oncology program, focusing on metrics of safety and efficiency. Methods A retrospective review of a prospectively maintained database of robotic procedures from July 2009 to October 2014 identifying trends in volume, operative time, complications, conversion to open, and 90-day mortality. Results Fourteen surgeons performed 1236 cases during the study period: thyroid (246), pancreas/duodenum (458), liver (157), stomach (56), colorectal (129), adrenal (38), cholecystectomy (102), and other (48). There were 38 conversions to open (3.1%), 230 complications (18.6%), and 13 mortalities (1.1%). From 2009 to 2014, operative volume increased (7 cases/month vs 24 cases/month; P < .001) and procedure time decreased (471 ± 166 vs 211 ± 140 minutes; P < .001) with statistically significant decreases for all years except 2014 when volume and time plateaued. Conversion to open decreased (12.1% vs 1.7%; P = .009) and complications decreased (48.5% vs 12.3%; P < .001) despite increasing complexity of cases performed. There were 13 deaths within 90 days (5/13 30-day mortality) and 2 (15.4%) were from palliative surgeries. Conclusions Implementation of a diverse robotic surgical oncology program utilizing multiple surgeons is safe and feasible. As operative volume increased, operative time, complications, and conversions to open decreased and plateaued at approximately 3 years. No unanticipated adverse events attributable to the introduction of this platform were observed.

Safety in numbers for cyclists beyond national-level and city-level data: a study on the non-linearity of risk within the city of Hong Kong

ObjectiveThis paper examines the relationship between bicycle collisions and the amount of cycling at the local level. Most previous research has focused on national and city comparisons, little is known...

Safety in numbers for cyclists—conclusions from a multidisciplinary study of seasonal change in interplay and conflicts

In many European countries, it is a political goal that future growth in local travel should be absorbed by sustainable transport modes. Concerns that increased walking and cycling produce more accidents have been countered by the “safety in numbers” (SiN) argument. According to SiN, the more walkers/cyclists there are in a population, the lower their risk. SiN has been demonstrated in cross sectional and longitudinal studies, but the mechanisms behind the effect have yet to be proven.Previous studies have mostly relied on register data. The current study, carried out in 2013 and 2014 tests the existence of this effect in a more controlled manner. This is achieved through the use of three data sets: (1) roadside survey data with cyclists, pedestrians and car drivers from Oslo carried out at three time points in the cycling season (2) a panel study covering the same time period, and (3) video observations at four different locations in Oslo. By exploiting the natural seasonal variation in cycling frequency, and by using a repeated measures design we can further control for other factors suggested to lie behind the SiN mechanism, such as differences in infrastructure and traffic culture.The results suggest that bicyclists experience a short term Safety in Numbers effect through the season. Each individual cyclist experiences fewer occasions of being overlooked by cars and fewer safety critical situations (near-misses). Video observation data confirm this pattern. However, the SiN effect seems to be countered by another mechanism taking place at the same time: the influx of inexperienced and risk-taking cyclists through the season. Thus car drivers and pedestrians also report to find themselves being surprised by cyclists in traffic late in the season.

Loss of safety in numbers and a novel driver of mass migration: radiotelemetry reveals heavy wasp predation on a band of Mormon crickets.

Coordinated movement of animals is a spectacular phenomenon that has received much attention. Experimental studies of Mormon crickets and locust nymphs have demonstrated that collective motion can arise from cannibalism that compensates for nutritional deficiencies arising from group living. Grouping into migratory bands confers protection from predators. By radiotracking migrating, Mormon crickets released over 3 days, we found that specialized, parasitoid digger wasps (Sphecidae) respond numerically and prey heavily on aggregated Mormon crickets leading to loss of safety in numbers. Palmodes laeviventris paralysed and buried 42% of tagged females and 8% of the males on the final day of tracking. Risk of wasps and Mormon crickets hatching on the same site is high and may drive nymphal emigration. A preference to provision offspring with adult female Mormon crickets can be explained by their greater fat content and larger size compared with males, improving survival of wasps during diapause.

Safety in Numbers: Why the Mere Physical Presence of Others Affects Risk‐taking Behaviors

AbstractAs social mammals, being in a group signals a state of relative security. Risk‐taking behavior in other social mammals formed the basis for our prediction that the mere physical presence of others, absent any social interaction, would create a psychological state of security that, in turn, would promote greater risk‐taking behavior. We investigated whether, why, and when the mere physical presence of others affects risk‐taking behaviors in three contexts: acceptance of greater financial volatility, attitudes toward risky gambles, and actual gambling behaviors. Results indicate that people in the mere physical presence of others make riskier decisions than people making identical decisions alone, and that feelings of security were the psychological mechanism behind this effect. Our results also suggest that the effect is contingent on whether people are surrounded by others who belong to the same social group. A meta‐analysis across all studies presented in this research reveals a highly reliable mere‐presence effect. Together, these results demonstrate that the mere physical presence of others can have a potent impact on risk‐taking behaviors. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Predation can select for later and more synchronous arrival times in migrating species

For migratory species, the timing of arrival at breeding grounds is an important determinant of fitness. Too early arrival at the breeding ground is associated with various costs, and we focus on one understudied cost: that migrants can experience a higher risk of predation if arriving earlier than the bulk of the breeding population. We show, using both a semi‐analytic and simulation model, that predation can select for later arrival. This is because of safety in numbers: predation risk becomes diluted if many other individuals, either con‐ or heterospecific, are already residing in the area. Predation risk dilution can also select for more synchronous arrival because deviating from the current population‐wide norm to earlier or later dates leads to higher predation risk or to failures in territory acquisition, respectively. The fact that selection for high arrival synchrony can in some cases be more important than selection for a specific date (early or late) within the season is an example of an ‘evolutionary priority effect’: whichever strategy – in this case a particular arrival time – becomes established in a population can remain stable over long periods of time; there are many possible equilibria (multiple stable states) which the population can remain at. Mixed arrival strategies are also possible under some circumstances.

Do Adolescent Employees Perceive the Risks of Workplace Violence? A Mixed Methods Study.

Objective: Adolescents are at risk for workplace violence (WPV) exposure but may not perceive it as a risk. The purpose of this study was to explore adolescent employees’ perceptions of safety from WPV. Methods: Using a qualitative dominant mixed methods design, 30 adolescent employees were recruited to complete a 36-item survey and individual interviews. Analyses included descriptive statistical techniques for survey responses, conventional content analysis for qualitative interview data, and mixed data analyses to explore differences in qualitative themes based on WPV exposure and gender. Results: Participants expressed mostly positive perceptions of safety despite 50% (n = 15) reporting WPV exposure. WPV exposure and gender did not appear to be associated with overall perceptions of safety but may be associated with safety in numbers. Most males had positive perceptions of safety. Conclusions: Adolescent employees want and deserve WPV training. Recommendations for nurses and other health professionals to assist adolescents with addressing health and safety issues in the workplace are provided.

Safety in numbers: the dilution effect and other drivers of group life in the face of danger

Animals can congregate in groups for many reasons, from reproductive assurance to improved foraging or predation efficiency, to avoiding themselves becoming the target of predation by other animals. It is the last category that is the focus of this review: group living as protection from predation. The drivers of group life in the face of danger are at the same time diverse and interlinked, with much potential for confusion between concepts. Here we review these concepts, using the dilution effect as a starting point. We construct a mathematical model that allows us to examine various features of the dilution effect and their connection to ecology. We also show the importance of including a time scale when modelling the dilution effect and how this translates into more realistic estimation of the fitness consequences of a diluted predation risk. The central role of the dilution effect in creating safety in numbers is underlined by showing how it may affect life-history evolution and result in the emergence of gregarious life-history strategies, even among sessile organisms limited in their abilities to exhibit behavioural responses to predation. Finally, we review the other central processes underpinning group protection from predation: the satiation effect, selfish herding, the confusion effect and group vigilance.