Sexual selection and the evolution of bird song: A test of the Hamilton-Zuk hypothesis

Summary Hamilton and Zuk (1982) suggested that secondary sexual characters evolve because they allow females to assess a potential mate's ability to resist parasites. A prediction of this theory is that the degree of elaboration of secondary sexual characters should be positively correlated with parasite load across species. In support of their hypothesis, Hamilton and Zuk reported a correlation across North American passerine species between haematozoa prevalence and both brightness and song complexity and variety, scored on a subjective six point scale. Here we show that this relationship is confounded by phylogenetic associations. We use quantitative data on song duration, inter-song interval, song continuity, song rate, song versatility, and song and syllable repertoire size for 131 species of European and North American passerines to test the Hamilton-Zuk hypothesis. Across species, there are significant negative relationships between haematozoa prevalence and song continuity, contrary to the direction predicted by Hamilton and Zuk. In accordance with their prediction, there is a positive correlation with song versatility. However, these relationships come about through taxonomic associations: within taxa there are no consistent relationships between any of the song variables and haematozoa prevalence. None of the other song variables correlate with haematozoa prevalence. We conclude that there is no evidence of an association between song elaboration and parasites. Offprint requests to: A.F. Read     

Prenatal detection of monosomy 21 mosaicism

We report a case of chromosomal mosaicism for monosomy 21 revealed in amniotic fluid cell culture. Ultrasound examination at 19 weeks' gestation showed in utero growth retardation and a complex cardiac malformation. A repeated amniocentesis confirmed the presence of monosomy 21 mosaicism. In view of the sonographically detected fetal abnormalities, termination of pregnancy was elected.     

The impact of the 1952 London smog event and its relevance for current wood-smoke abatement strategies in Australia

There is a certain complacency about air pollution in rural towns in Australia. An image of crystal clear skies seems to dominate general perceptions, and few locations actually monitor air pollution levels. Nevertheless, where measurements have been made, particulates have been shown to be the major type of air pollution, and they do reach levels expected to impact on human health. In this article, the contemporary attitudes and behaviour of the government and the population in rural and regional Australia are shown to have a strong resemblance to those that were prevalent prior to the smog events in London in December 1952. Wood smoke poses similar significant health issues in many countries. Insights obtained from the London events, together with more recent research results, are applied to the Australian situation to suggest policy options that are likely to be successful in overcoming the health effects of particulate pollution.

Implications: The contemporary attitudes and behaviour of the government and the population in rural and regional Australia are shown to have a strong resemblance to those that were prevalent prior to the smog events in London in December 1952. Insights obtained from the London event of 1952, together with more recent research results, are applied to the Australian situation to suggest policy options that are likely to be successful in overcoming the health effects of particulate pollution.     

An evaluation of four key methods for monitoring household waste prevention campaigns in the UK

Household waste prevention in England has been recognised in national strategy as a key component for future sustainable practice. To support the policy agenda, the Department of Environment, Food and Rural Affairs (Defra) in England has funded an extensive programme of fundamental research in the area. The specific research aim reported on here, in this Defra funded project, was to trial and assess methods for monitoring and evaluating approaches detailed in the National Resource and Waste Forum (NRWF)’s Household Waste Prevention Toolkit. The methods that formed the basis for the four research Objectives for the project were: using pilot and control areas (core Objective), tracking waste arisings, measuring specific activities and declared awareness and behaviour surveys. A primary objective of this research was to quantify the direct waste tonnage impacts of implementing a targeted household waste campaign in Dorset County, UK. A key performance indicator chosen for this assessment was the weight of waste collected at the kerbside from households. In an area where a waste prevention campaign is well planned and implemented then reductions in household waste arisings in pilot areas can be in the region of 2% per annum. This method for monitoring can be used, in the hands of an expert project team, to communicate to the public the direct benefits of waste prevention. It was found that there are a wide range of factors that need to be taken into account in the UK, and that these had hitherto been given little prominence, such as careful matching of pilot and control areas – this proved problematical in this research. However, a range of techniques used to support the methods, e.g. doorstepping surveys and focus groups could not show clear attributable waste prevention impacts but their findings could be used to direct new future messages to the public. The most successful and measurable campaign activities that were revealed by evaluation were: mail preference registrations, Home composting and doorstepping. An expert evaluation of all major methods found that no clear preference was revealed as to which were the most useful. None of the methods were judged very poor neither very good, all had major issues about their use. Tracking waste arisings and focus groups were assessed to be the best techniques in terms of input effort to output value. It is likely that waste prevention teams for household waste will need very careful training in the cost-effective use of the NRWF Toolkit before they are competent to apply it to a given place; the issues are more complex than were first thought.     

The UK landfill tax and the landfill tax credit scheme: operational weaknesses

The UK Landfill Tax and the related Landfill Tax Credit Scheme have now been in operation since October 1996. There have been a number of reviews to assess its operation and effectiveness that have led to some minor amendments. However, there continue to be concerns about operational weaknesses of the tax and the credit scheme. In particular, there is the risk that the tax may be evaded and there are fears that a lack of transparency and independence may undermine the fundamental principles of the Landfill Tax Credit Scheme. Following a recent report, the Secretary of State for the Department of the Environment, Transport and the Regions has set up an inquiry. This paper looks at some of the specific concerns that have been raised and the implications for waste management.     

The role of rhizofiltration and allelopathy on the removal of cyanobacteria in a continuous flow system

Environmental Science and Pollution Research - A continuous flow filtration system was designed to identify and quantify the removal mechanisms of Cyanobacteria (Microcystis aeruginosa) by...     

Persistence of fensulfothion in a sandy‐loam soil and uptake by rutabagas,carrots and radishes using microplots

Abstract

Field microplots were treated with 141 and 282 ppm fensulfothion and 37.1 and 74.2 ppm fensulfothion sulfone. These concentrations are equivalent to field treatment rates of 8.48 and 16.96 kg Al/ha, fensulfothion, and 2.23 and 4.47 kg Al/ha, fensulfothion sulfone, respectively, for banded application (10 cm wide, rows 80 cm apart). The half‐lives in a sandy loam soil were 30–39 and 14–23 days, respectively. Fensulfothion sulfone and sulfide were the main derivatives found in fensulfothion treated soil.

The maximum levels of these derivatives were 21.22 and 22.95 ppm, respectively for the 8.48 kg/ha treatment and 33.90 and 42.45 ppm, respectively, for the higher treatment, which occurred between 30–60 days.

Carrots appeared to take up more fensulfothion from soil than rutabagas or radishes. The residue levels at harvest decreased in the order carrot peel > pulp > rutabagas root > peel > pulp. Residue levels of fensulfothion and sulfone in radishes were similar to those found in rutabagas. The ratio sulfoxide/sulfone in rutabagas ranged from 0.4–1.5 and in carrots from 1.7–7.6. This phenomenon is thought to be due to oxidative enzyme systems present in rutabagas. Dimethyl phosphorothioic acid, but not dimethyl phosphoric acid was detected (max. 1.33 ppm) in some rutabagas samples but not in carrots.     

"It's not that simple": A collaborative comparison of sea ice environments, their uses, observed changes, and adaptations in Barrow, Alaska, USA, and Clyde River, Nunavut, Canada

The Arctic environment, including sea ice, is changing. The impacts of these changes to Inuit and I?upiat ways of life vary from place to place, yet there are common themes as well. The study reported here involved an exchange of hunters, Elders, and others from Barrow, Alaska, USA, and Clyde River, Nunavut, Canada, as members of a larger research team that also included visiting scientists. Although the physical environments of Barrow and Clyde River are strikingly different, the uses of the marine environment by residents, including sea ice, had many common elements. In both locations, too, extensive changes have been observed in recent years, forcing local residents to respond in a variety of ways. Although generally in agreement or complementary to one another, scientific and indigenous knowledge of sea ice often reflect different perspectives and emphases. Making generalizations about impacts and responses is challenging and should therefore be approached with caution. Technology provides some potential assistance in adapting to changing sea ice, but by itself, it is insufficient and can sometimes have undesirable consequences. Reliable knowledge that can be applied under changing conditions is essential. Collaborative research and firsthand experience are critical to generating such new knowledge.     

Biodegradation of an Epoxy-Based Thermoplastic Polyester, Poly(Hydroxy Ester Ether) in a Laboratory-Scale Compost System

An epoxy-based thermoplastic polyester, poly(hydroxy ester ether), was incubated under aerobic conditions in a laboratory-scale compost system for 168 days to evaluate its potential for biodegradation. Radiolabeled test polymer [uniformly ¹⁴C ring-labeled, poly(hydroxy ester ether)] was incorporated into a mature compost and a sludge-amended compost at a loading of 3 mg test polymer/g compost. ¹⁴C-Cellulose was used as the positive control and a biologically inhibited control reactor was used to assess abiotic degradation of the test polymer. Degradation of the test polymer was assessed by measuring the amount of ¹⁴C-CO₂ from each of the test reactors. In addition, at selected time intervals subsamples of the compost were collected and serially extracted with water, methanol, and dimethylformamide to monitor degradation of the ¹⁴C-test polymer and provide a partial characterization of the degradation intermediates. Extensive degradation of ¹⁴C-poly(hydroxy ester ether) was observed in the test reactors with degradation half-life of the parent polymer (t _1/2) of approximately 32 days. By the end of the study, only 2% of the total ¹⁴C activity in the test reactors was attributed to intact polymer, with most of the measurable ¹⁴C activity converted to either ¹⁴C-CO₂ (26% of total ¹⁴C activity) or nonextractable products (accounting for 60% of the total activity). In contrast to the test reactors, only 3% of the ¹⁴C-poly(hydroxy ester ether) added to the biologically inhibited control reactor was mineralized to ¹⁴C-CO₂. The results obtained from the microbially active and biologically inhibited compost systems indicate that the poly(hydroxy ester ether) polymer was degraded, at least in part, by a biologically mediated process.