The role of risk perceptions in the risk mitigation process: The case of wildfire in high risk communities

An important policy question receiving considerable attention concerns the risk perception–risk mitigation process that guides how individuals choose to address natural hazard risks. This question is considered in the context of wildfire. We analyze the factors that influence risk reduction behaviors by homeowners living in the wildland–urban interface. The factors considered are direct experience, knowledge of wildfire risk, locus of responsibility, fulltime/seasonal status, and self-efficacy. Survey data from three homeowner associations in the western U.S. are used to estimate the direct and indirect effects of this relationship. Our results indicate that the effects of knowledge and locus of responsibility are mediated by homeowners' risk perceptions. We also find that beliefs of self-efficacy and fulltime/seasonal status have a direct influence on risk reduction behaviors. Finally, we find, surprisingly, that direct experience with wildfire does not directly influence the risk perception–risk mitigation process.     

Addressing among-group variation in covariate effects using multilevel models

Multilevel models are used to model processes associated with hierarchical data structures. Despite infrequent use in the biological and environmental sciences, the use of these models with hierarchically-structured data conveys multiple advantages. These include the assessment of whether covariate effects differ among groups or clusters, and separate estimation of covariate effects by hierarchical level (thereby addressing atomistic and aggregation fallacy concerns). We illustrate these advantages using larval mayfly count data derived from annual surveys on the Mississippi River and a continuous covariate (water depth).     

The Importance of Selecting Appropriate Criteria for Calculating Acidity Critical Loads for Terrestrial Ecosystems Using the Simple Mass Balance Equation

The Simple Mass Balance (SMB) equationis commonly used throughout Europe for thecalculation of acidity critical loads for forestsoils. Different criteria can be set in themodel depending on whether the receptor (e.g. treeroots) is more sensitive to the toxic effects ofaluminium or to unfavourable pH conditions. Thispaper examines the effects on critical loadscalculations of using different criteria andcritical limits, and demonstrates the importanceof selecting the most appropriate and justifiablecriteria for the chosen receptor, since they caneffect the critical loads values obtained. Abrief review of the range of different criteriaand limits used throughout Europe is included. In addition, the gibbsite equilibrium constant,used in the SMB equation to represent therelationship between dissolved aluminium andhydrogen ions in soil solution, is discussed. This relationship is not generally described inthe literature as a criterion in the equation,but this work highlights the effects differentgibbsite values have on critical loadcalculations and the importance of applying themost appropriate value for the soil in therooting zone of the receptor.     

Individual-level patterns of division of labor in honeybees highlight flexibility in colony-level developmental mechanisms

Honeybee division of labor (DOL) has become a model system for exploring the genetic basis of complex traits and phenotypic plasticity. Although many highly informative behavioral studies have been conducted on this topic (both at the cohort and individual levels), most studies have focused on a few behavioral acts, such as the age of first foraging. Few studies have recorded large numbers of relatively complete individual-level patterns of DOL. Such fine-scale patterns would lay the foundation for rigorous molecular analyses of this phenomenon and allow us to differentiate between competing mechanistic models of DOL. Here, we record over 100 individual-level DOL patterns of bees living under natural conditions. We found that the transitions between castes (polyphenism states) are often gradual, with bees being in multiple castes at once. This is contrary to the traditional view that changes are abrupt. We also found that bees often skip castes, a key prediction of a recent model of DOL. We further confirm variation in the rate at which bees pass through castes and the age of first foraging. Taken together, these results greatly improve our understanding of this model system and allow for a strong revision of current models of honeybee DOL.     

Treatment of two insecticides in an electrochemical Fenton system

Abstract

The ability of an electrochemical Fenton system to degrade the organophosphorous insecticides malathion and methyl parathion was studied. A combination of hydrogen peroxide and electrochemically‐generated iron was found to be successful in degrading the two insecticides, and optimization of the system was pursued. Augmentation with near UV light at an intensity of 1.67xl0¹⁷ quanta/sec and centered at a wavelength of 370 nm improved the degradation of malathion at low iron concentrations but did not affect other treatments. Adding the hydrogen peroxide slowly over the course of treatment rather than all at once at the beginning of each treatment did, however, greatly improve the system. Removal efficiencies of 98.0% or greater were achieved for both pesticides.     

Spatiotemporal modeling of irregularly spaced aerosol optical depth data

Many advancements have been introduced to tackle spatial and temporal structures in data. When the spatial and/or temporal domains are relatively large, assumptions must be made to account for the sheer size of the data. The large data size, coupled with realities that come with observational data, make it difficult for all of these assumptions to be met. In particular, air quality data are very sparse across geographic space and time, due to a limited air pollution monitoring network. These “missing” values make it difficult to incorporate most dimension reduction techniques developed for high-dimensional spatiotemporal data. This article examines aerosol optical depth (AOD), an indirect measure of radiative forcing, and air quality. The spatiotemporal distribution of AOD can be influenced by both natural (e.g., meteorological conditions) and anthropogenic factors (e.g., emission from industries and transport). After accounting for natural factors influencing AOD, we examine the spatiotemporal relationship in the remaining human influenced portion of AOD. The presented data cover a portion of India surrounding New Delhi from 2000–2006. The proposed method is demonstrated showing how it can handle the large spatiotemporal structure containing so much missing data for both meteorologic conditions and AOD over time and space.     

The Yellow River in transition

Like many parts of the world, the Yellow River basin has problems associated with water scarcity, pollution, and flood risk. Analyses that focus only on the physical characteristics of these problems miss some of their most important social drivers. In this paper we identify some interlocking changes that have occurred as a consequence of economic reforms begun in China in 1978, and the implications of these changes for the Yellow River. The reforms have caused changes in the organisation of household production, increasing urbanisation and urban affluence, rapid industrialisation, and large scale spatial shifts in agricultural production. Rather than specific decisions it is these gradual changes that have affected the current status of the Yellow River and its basin. Our analysis suggests that at least some solutions to water problems in the Yellow River lie outside the basin, and beyond the realm of science or technology.     

Thermal instability and runaway criteria: The dangers of disregarding dynamics

Two exemplary exothermic processes, synthesis of nitroglycerine in a continuous stirred tank reactor (CSTR) and synthesis of the explosive RDX in a CSTR, are used to demonstrate the dangers of ignoring the system dynamics when defining criteria for thermal criticality or runaway. Stability analyses are necessary to prescribe such criteria, and for these systems prove the presence of dangerous oscillatory thermal instability which cannot be detected using the steady state thermal balances.