Risk of motor vehicle crash for older adults after receiving a traffic charge: A case–crossover study

Objective: After the age of 65, the number of motor vehicle crashes per mile driven increases. Traffic-related charges issued by law enforcement can help identify drivers who are at a higher risk of having a crash. This study examines the relationship between motor vehicle crashes and traffic-related charges among older adult drivers.

Methods: Iowa Department of Transportation crash data from 2011–2012 were linked with Iowa Court Information System data for moving violations that occurred during 2009–2012 for drivers over the age of 50. A time-stratified case–crossover design was used matching on time periods 1 year apart. Case exposure was defined as having a traffic-related charge 30 days before the crash. Control exposure was the same 30-day time period 1 year before the crash for each individual. Conditional logistic regression was used to analyze the self-matched pairs. Additional time periods of 31–60, 61–90, 91–120, 121–150, 151–180, and 181–210 days before the crash were also assessed.

Results: There were 38,171 adults at least 50 years of age with an Iowa driver's license who were involved in a crash in Iowa between 2011 and 2012. In addition, 13,129 adults over the age of 50 received a charge during 2009–2012. Relative to the control time period, experiencing a traffic-related charge in the 30-day time period before the crash increased the risk of a crash by 21% (odds ration [OR] = 1.21, 95% confidence interval [CI], 1.03–1.42) for all drivers included in the study. This crash risk was similar for adults aged 50–64 (OR = 1.20, 95% CI, 1.00–1.45) and adults 65 and older (OR = 1.24, 95% CI, 0.90–1.72). In the 30 days after receiving a traffic-related charge, the risk of a crash was also increased for crashes occurring in adverse weather (OR = 1.79, 95% CI, 1.12–2.84) or during night, dawn, or twilight (OR = 1.89, 95% CI, 1.31–2.72).

Conclusions: A traffic-related charge for an adult over the age of 50 indicates an increased risk of experiencing a crash in the 30 days following the charge. The risk for crashes occurring in adverse conditions or outside of daylight hours was also increased in the 30 days after receiving a traffic-related charge. The risk of experiencing a crash decreases as time passes after receiving a charge. Measures to restrict or increase driving safety during these conditions could help reduce the crash risk for older adults who receive a traffic-related charge.     

Changes in surface water quality from small-scale gold mining operations in the Surinamean rainforest

Abstract

Small-scale miners often engage in environmentally damaging activities, are subject to poor safety conditions, and utilize inefficient mineral extraction technologies. Here, we explore environmental impacts to surface waters from regional artisanal small-scale gold placer mining operations conducted in iron and aluminum-rich saprolites found within the lateritic, interior Amazon rainforest of Suriname. Heavy equipment was utilized to release gold from its host material followed by amalgamation and gravity separation. In contrast with background tributary recordings, streams adjacent to these gold mining operations consistently contained turbidity measurements that exceeded United States’ EPA guidelines for aquatic species of 50 nephelometric turbidity units and were typically in the hundreds to thousands of units. Turbidity was further heightened in association with precipitation events. Mercury played a prominent role in whole ore amalgam concentration practices. Freshwater fish from the region were found to harbor mercury that encroached upon public health criteria. Dissolved phase metals present further ecotoxicological challenges to the region, but their association with mining activities was less clear. These findings collectively reveal that small-scale placer gold mining practices in the Surinamese rainforest result in an increase of suspended sediments and release of mercury into waterways that could impact communities that depend upon local fisheries.     

Fundamental insights on when social network data are most critical for conservation planning

As declines in biodiversity accelerate, there is an urgent imperative to ensure that every dollar spent on conservation counts toward species protection. Systematic conservation planning is a widely used approach to achieve this, but there is growing concern that it must better integrate the human social dimensions of conservation to be effective. Yet, fundamental insights about when social data are most critical to inform conservation planning decisions are lacking. To address this problem, we derived novel principles to guide strategic investment in social network information for systematic conservation planning. We considered the common conservation problem of identifying which social actors, in a social network, to engage with to incentivize conservation behavior that maximizes the number of species protected. We used simulations of social networks and species distributed across network nodes to identify the optimal state-dependent strategies and the value of social network information. We did this for a range of motif network structures and species distributions and applied the approach to a small-scale fishery in Kenya. The value of social network information depended strongly on both the distribution of species and social network structure. When species distributions were highly nested (i.e., when species-poor sites are subsets of species-rich sites), the value of social network information was almost always low. This suggests that information on how species are distributed across a network is critical for determining whether to invest in collecting social network data. In contrast, the value of social network information was greatest when social networks were highly centralized. Results for the small-scale fishery were consistent with the simulations. Our results suggest that strategic collection of social network data should be prioritized when species distributions are un-nested and when social networks are likely to be centralized.     

Variations in Base‐Flow Nitrate Flux in a First‐Order Stream and Riparian Zone1

Abstract: Nonpoint source pollution, which contributes to contamination of surface waters, is difficult to control. Some pollutants, particularly nitrate (), are predominantly transmitted through ground water. Riparian buffer zones have the potential to remove contaminants from ground water and reduce the amount of that enters surface water. This is a justification for setting aside vegetated buffer strips along waterways. Many riparian zone hydrologic models assume uniform ground‐water flow through organic‐rich soil under reducing conditions, leading to effective removal of ground‐water prior to discharge into a stream. However, in a small first‐order stream in the mid‐Atlantic coastal plain, base‐flow generation was highly variable (spatially and temporally). Average base‐flow loads were greater in winter than summer, and higher during a wetter year than in dryer years. Specific sections of the stream consistently received greater amounts of high ground water than others. Areas within the riparian zone responsible for most of the exported from the watershed are termed “critical areas.” Over this 5‐year study, most of the exported during base flow originated from a critical area comprising less than 10% of the total riparian zone land area. Allocation of resources to address and improve mitigation function in critical areas should be a priority for continued riparian zone research.     

Turning the tide: Enabling sustainable development for Africa's mobile pastoralists

Sustainable development for Africa's mobile pastoralists is slowly becoming a reality. Success depends to a large extent on understanding the dynamics of drylands environments, accepting the logic of customary mobile livestock keeping, and enabling effective governance. Appropriate investment in pastoralism requires a clear understanding of the values that are attached to it and innovative approaches to marketing of the goods and services that emanate from the system. To make development truly sustainable it is imperative that the environmental services of pastoralism are recognised, rewarded and promoted. Constraints to sustainable pastoral development include low and misdirected public and private investment, weak security of resource rights, low human capital, weak pastoral voice and poor governance. Successful and sustainable development is observed in pastoral regions where customary governance has been legitimized, resource rights secured and economic development of the pastoral sector, as opposed to transformation of livestock keeping, has prevailed. This article presents state‐of‐the‐art knowledge on sustainable pastoralism, gathered through the GEF/UNDP/IUCN World Initiative for Sustainable Pastoralism (WISP), with data and case studies taken from three recently published WISP reports: “Global Economic Review of Pastoralism”, “Pastoralism as Conservation in the Horn of Africa”, and “Policy Impacts on Pastoral Environments”.     

The influence of institutions and organizations on urban waste collection systems: an analysis of waste collection system in Accra, Ghana (1985-2000)

Urban waste collection system is a pivotal component of all waste management schemes around the world. Therefore, the efficient performance and the success of these schemes in urban pollution control rest on the ability of the collection systems to fully adapt to the prevailing cultural and social contexts within which they operate. Conceptually, institutions being the rules guiding the conduct of public service provision and routine social interactions, waste collection systems embedded in institutions can only realize their potentials if they fully evolve continuously to reflect evolving social and technical matrices underlying the cultures, organizations, institutions and social conditions they are designed to address. This paper is a product of an analysis of waste collection performance in Ghana under two different institutional and/or organizational regimes; from an initial entirely public sector dependence to a current mix of public-private sector participation drawing on actual planning data from 1985 to 2000. The analysis found that the overall performance of waste collection services in Ghana increased under the coupled system, with efficiency (in terms of total waste clearance and coverage of service provision) increasing rapidly with increased private-sector controls and levels of involvement, e.g. for solid waste, collection rate and disposal improved from 51% in 1998 to about 91% in the year 2000. However, such an increase in performance could not be sustained beyond 10 years of public-private partnerships. This analysis argues that the sustainability of improved waste collection efficiency is a function of the franchise and lease arrangements between private sector group on the one hand and public sector group (local authorities) on the other hand. The analysis therefore concludes that if such franchise and lease arrangements are not conceived out of an initial transparent process, such a provision could undermine the overall sustainability of private sector initiatives in collection services delivery in the long term, as in the case of the Accra example.     

Base cation depletion, eutrophication and acidification of species-rich grasslands in response to long-term simulated nitrogen deposition

Pollutant nitrogen deposition effects on soil and foliar element concentrations were investigated in acidic and limestone grasslands, located in one of the most nitrogen and acid rain polluted regions of the UK, using plots treated for 8-10years with 35-140kg Nha(-2)y(-1) as NH(4)NO(3). Historic data suggests both grasslands have acidified over the past 50years. Nitrogen deposition treatments caused the grassland soils to lose 23-35% of their total available bases (Ca, Mg, K, and Na) and they became acidified by 0.2-0.4 pH units. Aluminium, iron and manganese were mobilised and taken up by limestone grassland forbs and were translocated down the acid grassland soil. Mineral nitrogen availability increased in both grasslands and many species showed foliar N enrichment. This study provides the first definitive evidence that nitrogen deposition depletes base cations from grassland soils. The resulting acidification, metal mobilisation and eutrophication are implicated in driving floristic changes.     

Pesticides in urban multiunit dwellings: hazard identification using classification and regression tree (CART) analysis

Many units in public housing or other low-income urban dwellings may have elevated pesticide residues, given recurring infestation, but it would be logistically and economically infeasible to sample a large number of units to identify highly exposed households to design interventions. Within this study, our aim was to devise a low-cost approach to identify homes in public housing with high levels of pesticide residues, using information that would allow the housing authority and residents to determine optimal strategies to reduce household exposures. As part of the Healthy Public Housing Initiative, we collected environmental samples from 42 public housing apartments in Boston, MA, in 2002 and 2003 and gathered housing characteristics; for example, household demographics and self-reported pesticide use information, considering information available with and without a home visit. Focusing on five organophosphate and pyrethroid pesticides, we used classification and regression tree analysis (CART) to disaggregate the pesticide concentration data into homogenous subsamples according to housing characteristics, which allowed us to identify households and associated networks impacted by the mismanagement of pesticides. The CART analysis demonstrated reasonable sensitivity and specificity given more extensive household information but generally poor performance using only information available without a home visit. Apartments with high concentrations of cyfluthrin, a pyrethroid of interest given that it is a restricted use pesticide, were more likely to be associated with Hispanic residents who resided in their current apartment for more than 5 yr, consistent with documented pesticide usage patterns. We conclude that using CART as an exploratory technique to better understand the home characteristics associated with elevated pesticide levels may be a viable approach for risk management in large multiunit housing developments.     

Relative importance of male and territory quality in pairing success of male rock ptarmigan (Lagopus mutus)

We studied pairing success in male rock ptarmigan (Lagopus mutus) in northern Alaska to learn whether males obtaining more females possessed phenotypic traits that influenced female choice directly, whether these traits permitted males to obtain territories favored by females, or whether both processes occurred. The number of females per male varied from zero to three. Several male and territory traits were significantly correlated with number of females per male. We used multiple regression to obtain a single measure of male quality and a single measure of territory quality. These measures of male and territory quality correlated with each other and with male pairing success. We used path analysis to separate direct effects of male quality on pairing success from indirect effects due to high-quality males obtaining high-quality territories. Both direct and indirect pathways had significant effects on pairing success, and direct and indirect effects of male traits on pairing success were about equal. This study illustrates an analytical approach for estimating the relative importance of direct and indirect causal relationships in natural systems. Received: 13 January 1998 / Accepted after revision: 7 November 1998