Genetic monogamy in the common loon (Gavia immer)

We conducted behavioral observations and genetic analysis on breeding pairs of common loons in the upper Great Lakes region from 1993 through 1995 to look for behavioral evidence of extrapair copulations (EPCs) and to determine parentage of young. Pairs remained close to each other (usually within 20 m) during the pre-laying period, leaving little opportunity for EPCs to occur. Males and females both maintained physical proximity by approaching each other when they became separated. Copulations were obvious but infrequent, occurring about once every other day during the pre-laying period. Multilocus DNA fingerprinting was consistent with behavioral findings: 58 young from 47 different families were all genetic offspring of parents that raised them. Perfect genetic monogamy (genetic parentage of young by parents that rear them) in loons might arise as a consequence of the need for vigorous territorial defense to prevent territorial takeover. Received: 8 August 1996 / Accepted after revision: 22 March 1997     

A Bayesian assessment of the effect of highway bypasses in Iowa on crashes and crash rate

Introduction

A common contention is that the construction of highway bypasses negatively impacts the economy of local communities by reducing pass-by traffic for businesses. However, as access to specific business' account records is limited, this impact is difficult to quantify. Another common contention is that bypasses contribute to a reduction in overall crashes in the community and in the surrounding areas. Even though a large number of bypasses have been constructed in the State of Iowa over the past several years, their actual impact in terms of traffic safety has not been quantified.

Objectives

This study seeks answers to the following questions: (a) Are bypasses in Iowa associated with a reduction in crash frequencies and crash rates on the bypassed highway? (b) Do bypasses in Iowa introduce a reduction of overall crash frequencies and rates or do they merely shift crashes from the highways through the communities to the bypasses with no significant overall reduction?

Method

We obtained crash information from the Iowa DOT at 19 sites on which a bypass was constructed sometime during the past 23 years. We also obtained the same information at six sites used as comparison sites on which no bypasses were constructed at least until 2005. We them employed a Bayesian approach to estimating the association between the construction of the bypass and crash rates, while also accounting for other factors.

Results

The construction of bypasses in Iowa is associated with a significant increase in traffic safety both on the main road through town and on the combined main road and bypass roadway.     

Interactions of sodium azide with triazine herbicides: effect on sorption to soils

Sodium azide (NaN(3)) is one of the biocides commonly used to inhibit microbial growth during sorption experiments. However, a few reports have suggested that NaN(3) can react with the analyte of interest. In this study, the interactions of NaN(3) with triazine herbicides were investigated and the effect of atrazine transformation on its sorption to soil was evaluated. The concentration of atrazine in the presence of NaN(3) decreased significantly over period of time. After 14 days, only 38% of the initial atrazine concentration (10 mg l(-1)) was detected in a solution containing 1,000 mg l(-1) NaN(3) at pH 5.5. The magnitude and the rate of atrazine transformation increased with increase in NaN(3) load and with decrease in pH. In contrast to atrazine behavior, the concentrations of prometon and ametryn did not change during the experiment. GC/MS analysis indicated that the chlorine atom of atrazine is replaced by the azide group yielding 2-azido-4-(ethylamino)-6-(isopropylamino)-s-triazine. Atrazine transformation by NaN(3) significantly affected sorption of herbicide to soil. The presence of NaN(3) affects indirectly the sorption of atrazine due to competitive effect of its derivative. Our results demonstrated that the application of NaN(3) as a biocide in sorption-desorption experiments must be carefully evaluated. This issue is vital for sorption experiments conducted over long periods of time or/and with concentration of NaN(3) higher than 100 mg l(-1).     

The influence of individual differences on organizational safety attitudes

Workplace accidents cost organizations and the economy billions of dollars annually, disabling and injuring millions of employees. Employee attitudes toward safety have been shown to relate to safe workplace behavior. In an effort to determine what contributes to stronger employee attitudes toward safety, we examined the relationships between safety attitudes and a wide array of individual differences reflecting preferences and tendencies toward risk and control. Using a sample of 190 engineering and occupational safety students from two universities, we found that agreeableness, conscientiousness, prevention regulatory focus, and fatalism related significantly to all six safety attitudes examined. Regression analyses demonstrated that agreeableness, prevention focus, and fatalism significantly related to safety attitudes when controlling for the other individual differences. This study illustrates the utility of examining individual differences when predicting safety-related attitudes.     

Can level of safety climate predict level of orientation toward safety in a decision making task?

Establishing the relationship between level of safety climate and safety performance is a current challenge. This work examines the relationship between level of safety climate and orientation toward safety in the decision making process and choice. Alternatively, this work seeks to answer the question of whether level of safety climate can predict safety-oriented decision making. A generalized safety climate questionnaire and a decision making simulation are utilized to examine this relationship. The results indicate that level of safety climate is not a significant predictor of the decision process; however, it was found to be a significant predictor of the selection of safer choices.     

Past experiences and future expectations generate context-dependent costs of foraging

Because environments can vary over space and time in non-predictable ways, foragers must rely on estimates of resource availability and distribution to make decisions. Optimal foraging theory assumes that foraging behavior has evolved to maximize fitness and provides a conceptual framework in which environmental quality is often assumed to be fixed. Another more mechanistic conceptual framework comes from the successive contrast effects (SCE) approach in which the conditions that an individual has experienced in the recent past alter its response to current conditions. By regarding foragers’ estimation of resource patches as subjective future value assessments, SCE may be integrated into an optimal foraging framework to generate novel predictions. We released Allenby’s gerbils (Gerbillus andersoni allenbyi) into an enclosure containing rich patches with equal amounts of food and manipulated the quality of the environment over time by reducing the amount of food in most (but not all) food patches and then increasing it again. We found that, as predicted by optimal foraging models, gerbils increased their foraging activity in the rich patch when the environment became poor. However, when the environment became rich again, the gerbils significantly altered their behavior compared to the first identical rich period. Specifically, in the second rich period, the gerbils spent more time foraging and harvested more food from the patches. Thus, seemingly identical environments can be treated as strikingly different by foragers as a function of their past experiences and future expectations.     

Frequency analysis of hazardous material transportation incidents as a function of distance from origin to incident location

According to the United States Department of Transportation (USDOT), more than 3.1 billion tons of hazardous materials (HazMat) are shipped within the United States annually. This averages to about 800,000 individual shipments of HazMat per day, of which 300,000 are shipments of petroleum/flammable–combustible liquids. This paper presents a temporal trend study (1995–2004) of 2145 HazMat incidents occurring through the transportation of flammable/combustible liquids. The study also correlates between HazMat incidents and distances between shipment origin and incident location. These distances attained through great circle calculations since the data compilation did not allow for the identification of specific routes taken in commodity transport. Findings of this study illustrate a bimodal distribution of frequency as a function of the logarithm of the Distance with first mode (less than 105 miles) mean of 24 [km] and second mode mean of 1061 [km]. Additionally, transport phase introduced no significance to the distribution of frequencies.