RESUMEN

To investigate whether the classic bystander effect is unique to humans, the effect of bystanders on rat helping was studied. In the presence of rats rendered incompetent to help through pharmacological treatment, rats were less likely to help due to a reduction in reinforcement rather than to a lack of initial interest. Only incompetent helpers of a strain familiar to the helper rat exerted a detrimental effect on helping; rats helped at near control levels in the presence of incompetent helpers from an unfamiliar strain. Duos and trios of potential helper rats helped at superadditive rates, demonstrating that rats act nonindependently with helping facilitated by the presence of competent-to-help bystanders. Furthermore, helping was facilitated in rats that had previously observed other rats' helping and were then tested individually. In sum, the influence of bystanders on helping behavior in rats features characteristics that closely resemble those observed in humans.

RESUMEN

Water scarcity is intensified by drought, a phenomenon that impacts many sectors of society and affects virtually all climate zones. The Palmer drought indices are widely used by scientists and policy makers to understand drought and model its components. Despite the spatial heterogeneity and variability in variables required by the Palmer model, regional index values are most commonly used for real-time drought assessment. Local stakeholders charged with developing flexible and tailored water management policies have articulated the need for drought indices calculated at finer spatial resolutions than a regional scale. We use the Pacific Northwest United States (U.S.) as a study area to demonstrate the differences between drought indices calculated for U.S. climate divisions with those calculated at a 0.5° by 0.5° latitude/longitude resolution. Our results indicate that regional values of the two cumulative Palmer drought indices do not represent finer-resolution values well. For half of the study area, the pictures of drought (as determined by regional and finer-resolution values) are drastically different more than 30% of the time. Thus, quite often water managers do not have a clear understanding of the relative severity of drought in their area, which can have serious implications for drought mitigation and adaptation.

Asunto(s)

Planificación en Desastres , Sequías , Modelos Teóricos , Adaptación Fisiológica/fisiología , Clima , Humanos , Noroeste de Estados Unidos

RESUMEN

The historical approach to assessing health risks of environmental chemicals has been to evaluate them one at a time. In fact, we are exposed every day to a wide variety of chemicals and are increasingly aware of potential health implications. Although considerable progress has been made in the science underlying risk assessments for real-world exposures, implementation has lagged because many practitioners are unaware of methods and tools available to support these analyses. To address this issue, the US Environmental Protection Agency developed a toolbox of cumulative risk resources for contaminated sites, as part of a resource document that was published in 2007. This paper highlights information for nearly 80 resources from the toolbox and provides selected updates, with practical notes for cumulative risk applications. Resources are organized according to the main elements of the assessment process: (1) planning, scoping, and problem formulation; (2) environmental fate and transport; (3) exposure analysis extending to human factors; (4) toxicity analysis; and (5) risk and uncertainty characterization, including presentation of results. In addition to providing online access, plans for the toolbox include addressing nonchemical stressors and applications beyond contaminated sites and further strengthening resource accessibility to support evolving analyses for cumulative risk and sustainable communities.