Do the elongated eye stalks of Diopsid flies facilitate rival assessment?

The elongated eye span of male Diopsid flies is a sexually selected character that scales positively with body size. Previously, the duration of agonistic contests was found to increase as rival body size and eye span disparities decreased. Hence, along with its role in mate choice, eye span seems to facilitate mutual assessment of rival size. However, such results are also expected in the absence of rival assessment, when each individual persists according to its own size-dependent internal threshold. Here, we reanalyze these contests to distinguish between these two hypotheses using two measures of size: body length and eye span. Mutual assessment predicts that contest duration should increase with loser size and decrease with winner size. In contrast, our results were more consistent with self-assessment: We found a positive relationship between loser size and contest duration, whereas winner size did not affect contest duration. Thus, flies did not appear to assess the size of their rivals, indicating that the mutual assessment function of eye span elongation may be less important than previously suspected. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Government Sponsored Air Pollution Research Relating to Agriculture

The absorption of hydrogen sulfide and methyl mercaptan by aqueous solutions of chlorine, sodium hydroxide, and chlorine plus sodium hydroxide was studied using a two-inch diameter absorption column packed with ¼ inch Intalox saddles. Absorption rates were noticeably affected by chemical reactions occurring in the aqueous chlorine and hydroxide media. These solutions were studied as a means of controlling sulfur-containing gas emissions from kraft paper mills. The absorption studies indicated that aqueous chlorine solutions at a pH above 12 were effective absorbents for hydrogen sulfide removal in absorption equipment designed to tolerate sulfur in suspension. The absorption of methyl mercaptan in aqueous chlorine solutions appeared to be impractical since dimethyl disulfide was apparently the only product formed and was stripped from the tower by the gas stream. Sodium hydroxide solution was an effective absorbent for both methyl mercaptan and hydrogen sulfide when hydroxide to sulfide or mercaptan feed ratios were greater than 1 or 1.8, respectively. The mercaptan absorption coefficient was approximately twice that for sulfide absorption.     

Sequential analysis of aggressive interactions in the stalk-eyed fly Teleopsis dalmanni

Understanding the mechanisms and determinants of conflict resolution is of great theoretical and practical importance because the outcome of contests between males over limited resources such as mates, territories, and food has profound fitness consequences. Despite the large literature on the theory of conflict resolution, relatively few empirical studies explicitly test predictions related to contest structure for these models. In sexually dimorphic species of stalk-eyed flies (Diopsidae), males engage in characteristic aggressive interactions over both females and food resources. We used sequential analysis of aggressive interactions between dyads of male stalk-eyed flies to investigate patterns of escalation, behavioral matching, and physical contact in order to distinguish between three common models of conflict resolution: the sequential assessment model, the cumulative assessment model, and the energetic war of attrition. Stalk-eyed flies were shown to engage in both low- and high-intensity behaviors during interactions with patterns of escalation and no de-escalation. Aggressive interactions did not demonstrate behavioral matching between winners and losers. Stalk-eyed flies also escalated to behaviors that included physical contact without injuries. Our results provide support for the sequential assessment model based on patterns of escalation with no de-escalation, behavioral mismatching, and behaviors which include physical contact but no injuries.     

MEAD: an interdisciplinary study of the marine effects of atmospheric deposition in the Kattegat

This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions.     

Advanced paternal age,infertility, and reproductive risks: A review of the literature

Advanced paternal age (APA) is associated with infertility and other reproductive risks. Studies looking at APA and outcomes have used different paternal age cut-offs, which has complicated systematic evaluations of reproductive risk associated with paternal aging. This review of the literature suggests that the impact of paternal aging on adverse reproductive outcomes is small, but significant. Studies suggest the incidence of paternal age effect disorders attributed to de novo autosomal dominant mutations is less than 0.5%. Other risks associated with APA include infertility, miscarriage, birth defects, poor neurodevelopmental outcomes, and childhood cancer. Although the increasing prevalence of APA has mirrored the rise in maternal age, this topic has not received similar attention. In this review, we summarize the available literature on the reproductive risks associated with APA to provide a framework for comprehensive genetic counseling and evidence-based management of APA pregnancies.     

Assessing who gains and who loses from natural resource policy: Distributional information and the public participation process

Recent legislation mandates an increased role for public participation in natural resource policy making. This paper presents an operational way to provide those impacted with relevant information and to enable public officials to assess public reaction to proposed policies. The methodology transforms results obtained from a multisector model of income formation and distribution into positive economic measures of distributional impacts. The usefulness of the methodology is illustrated in the context of a policy to increase coal surface mining on public lands.     

Genetic Variability in Swayne's Hartebeest, an Endangered Antelope of Ethiopia

Abstract: Swayne's hartebeest ( Alcelaphus buselaphus swaynei ) is an endangered antelope that survives in four or five relict populations in Ethiopia. We examined the two main populations (Senkele and Nechisar) for mitochondrial (D-loop) and nuclear (microsatellite) variability in order to measure levels of genetic variation within the subspecies and degree of differentiation between populations. For comparison, we examined samples from a large population of red hartebeest ( Alcelaphus buselaphus caama ). Both swaynei and caama exhibited high levels of variation. There was significant differentiation between the populations of swaynei at Senkele and Nechisar, and gene diversity in Nechisar, the smaller of the two populations, was significantly lower than that in Senkele. Many mitochondrial haplotypes and microsatellite alleles present at high frequencies among the Senkele individuals were missing in Nechisar, suggesting that the translocation of animals from Senkele undertaken in 1974 did not contribute notably to the gene pool in Nechisar. Subsamples taken from Senkele in 1988 and 1995 showed a significant change in allele frequencies, a change that probably can be attributed to a massive population decline during this period. We recommend that both populations be protected in situ to maintain as much as possible of the diversity that exists within the taxon and that a breeding program be established. In spite of the earlier unsuccessful attempt, we argue that translocation of animals for enhancement of population size as well as genetic variation in Nechisar should be considered.