An exploratory study with the proton microprobe of the ontogenetic distribution of 16 elements in the shell of living oysters (Crassostrea virginica)

Study of the chemical composition of shell of exoskeletonous organisms in the past has required the sacrifice of the organism. Because the beam of the proton microprobe is relatively nondestructive and analyzes the surface layer of the shell, organisms do not have to be killed. The present paper presents results of a preliminary experiment in which distribution of elements (Na to Sr) in shell of living juvenile oysters, Crassostrea virginica (Gmelin), was studied in situ with a proton microprobe at monthly intervals for four months. The relative concentration of 16 elements was measured in the newly deposited prismatic edge of the right valve of three oysters reared in controlled laboratory conditions. Na, Mg, Al, Si, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Br, and Sr were detected in concentrations as low as a few parts per million relative to the concentration of standards added to pure CaCO₃. Concentration of elements varied nominally among shells of the three individual oysters and in their successive ontogenetic stages. Fluctuations in concentration of Na, Mg, S, Cl, Ca, Mn, Fe, Cu, and Zn were generally similar in the two normally growing oysters, but differed from those in the oyster that stopped growing. Trends in concentration of Al, Si, and Sr were similar in the three oysters: those of Br were variable. Relative concentrations of Na, Cl, S, Mn, Fe, and Zn increased slightly with age of oysters, that of the other elements stayed relatively constant. Concentration of most elements was higher in shell than in seawater. Variable concentrations, especially of Na, Cl, and Si in valve edges, tend to support the hypothesis of earlier workers that separate mineral phases are present as impurities entrapped within the shell during calcification.     

Questionable accountability: MSF and Sphere in 2003

This article examines the relationship between Médecins Sans Frontières (MSF) and the Sphere Project. Prior to revisiting the concerns MSF had with the project, it looks at factors that give rise to differences between NGOs and cites some reasons for why an organisation such as MSF would not embrace such a project and clarifies some key elements of MSF-style humanitarianism. The author revisits the original concerns and arguments presented by MSF when it decided not to participate beyond assisting with the establishment of technical standards and key indicators for the handbook. This is followed by a critical discussion examining these concerns and counter-criticism with reference to experiences a few years after the inception of Sphere. It concludes with MSF's perceptions and stance regarding Sphere and accountability in 2003.     

Metals Associated with Suspended Sediments in Lakes Erie and Ontario, 2000–2002

Sediment traps were deployed in the three major basins of Lake Erie, and the central (Mississauga) basin of Lake Ontario, and refurbished seasonally over the period 2000–2002. In Lake Ontario, sediment down-flux rates and corresponding contaminant down-flux rates were highest in winter during periods of unstratified thermal conditions, and generally increased with depth due to the influence of resuspended bottom sediments during all sampling periods. Lake Ontario suspended sediments exhibited the highest concentrations of metals; concentrations of mercury and lead frequently exceeded guideline values for bottom sediments. Contaminant levels in Lake Ontario suspended sediments were similar to concentrations in bottom sediments in the same area. There was a spatial trend toward higher suspended sediment metals concentrations from the eastern basin to the western basin of Lake Erie, which is similar to the trend in bottom sediment contamination. In the eastern basin of Lake Erie, which is the deepest area of the lake, there was no trend in down-flux rate with depth in 2001; however, down-flux rates increased with depth in 2002. Suspended sediments in the western basin of Lake Erie were determined to be largely resuspended bottom sediments; all western basin samples collected in the study exceeded the guideline value for mercury (0.486 μg/g).     

Public policy, private landholders: perspectives on policy mechanisms for sustainable land management

A variety of tools can be employed in support of environmental policy objectives, but achieving preferred outcomes also requires the cooperation of private landholders and others with vested interests in the land. The Land Stewardship project in the state of Victoria, Australia, is an initiative devoted to exploring the ways in which private landholders could be encouraged towards more sustainable land management. Following the view that the success of policy initiatives is contingent on effective stakeholder engagement, a component of the Land Stewardship project involved a dialogue with landholders about policy tools (e.g., regulation, economic instruments) that might be deployed to encourage improved land management practices. This paper provides an account of the views and attitudes of landholders, as revealed in a series of three workshops, which consisted of discussions about the factors influencing agriculture, participants' interpretations of sustainability, and policy methods. The focus of the paper is on what landholders believe to be the strengths and limitations of standard policy tools, and the essential requirements for these tools to deliver the best land management outcomes. One of the main findings of the project was a 'preference hierarchy' in respect of policy methods, according to which the strongest support was expressed for voluntary and education-based tools, followed by market-based instruments, with command-and-control regulation identified as a measure of 'last resort'. In the paper we reflect also on how the views and outlook of landholders should be positioned relative to other inputs in the design of policy interventions.     

Evoking trust in the nutrition counselor: why should we be trusted?

The virtue of trust is often spoken of as central to the work of dietitians working in nutrition counseling, especially in the context of disordered eating/eating disorders nutrition therapy. Indeed, dietitians are purported to be the most trusted source of information on nutrition and food by professional associations such as Dietitians of Canada. Here trust is explored through educational, relational, and virtue theory in order to elucidate trusts meaning and relevance to dietitians work and interactions with each other, including the general public. If dietitians are to continue to be trusted during times of skepticism in expert knowledge, reflexivity, active contestation, and moral testing in the context of our socio-political milieu need be employed so that we as a profession may respond to clients in respectful, authentic, meaningful ways; practices worthy of our trust.     

Genetic relatedness and eusociality: parasite-mediated selection on the genetic composition of groups

Summary Contrary to the expectations of kin selection theory, intracolony relatedness in eusocial insects is often low. We examined the idea that associations of low relatedness (high genetic variability) may be advantageous because of negative frequency-dependent selection on common host phenotypes by rapidly evolving parasites and pathogens. Using the natural host-parasite system of the bumble bee Bombus terrestris and its intestinal trypanosome Crithidia bombi, we investigated the transmission properties of parasites in host groups. Within naturally infested nests and in artificially constructed groups of workers, prevalence of infestation increased with time of exposure (Table 1). The susceptibility of isolated groups of workers to the parasites to which they were exposed differed with identity and natural infestation of their nest of origin (Table 2). In addition, those workers that were related to the individual introducing an infection to their group were more likely to become infested than were unrelated workers (Table 3). Although the bumble bee workers in experimental boxes appeared to differ in behavior toward kin and non-kin, making more physical contacts with kin, we found no discernible relationship between number of physical contacts and prevalence of infestation in a group. Therefore, we conclude that differences in parasite transmission reflected interactions among different host and parasite phenotypes. This system thus demonstrates the factors necessary for negative frequency-dependent selection by parasites on common host phenotypes - variability for susceptibility and infectiousness in host and parasite populations and similarity for these traits among related individuals. If, as we show here, high genetic relatedness within groups enhances parasite transmission, kin directed altruism may increase the risk of contracting parasites and infectious diseases. Therefore, parasites and pathogens may be an important force moderating the genetic structure of social groups. Offprint requests to: J.A. Shykoff at the present address     

Ducking for cover in the ‘blame game’: news framing of the findings of two reports into the 2010–11 Queensland floods

After a disaster, the media typically focus on who is to blame. However, relatively little is known about how the narrative of blame plays out in media coverage of the release of official disaster reports. This paper examines coverage by two Australian newspapers (The Courier‐Mail and The Australian) of the release of the Queensland Floods Commission of Inquiry's Interim Report and its Final Report to identify whether and how the news frame of blame was used. Given the absence of blame in the Final Report, the newspapers resorted to the frame of ‘failure’ in news and feature articles, while continuing to raise questions in editorials and opinion pieces about who was to blame. This study argues that situating coverage of the report within the news frame of failure and questioning who was to blame for the disaster limited the media's ability to facilitate a discussion about the prevention of similar disasters in the future.     

Optimising the timing for nuchal translucency measurement

It appears from current evidence that the most effective screening strategy for Down syndrome will involve a combination of first trimester nuchal translucency and serum biochemistry, whether performed in the first or second trimester. The aim of this study was to determine the optimum gestation based upon menstrual dates at which to schedule nuchal translucency (NT) measurement for the evaluation of fetal Down syndrome risk. Five thousand eight hundred and thirty-five pregnancies had an ultrasound scan scheduled between 11 and 14 completed weeks of gestation based upon either the last menstrual period (n = 3199) or a prior ultrasound scan (n = 2636). For last menstrual period-based ultrasound scans, with advancing gestation the frequency of missed miscarriage significantly decreased (p = 0.009, chi squared test), as did the need to reschedule a further scan because the gestation of the scheduled scan was too early to measure NT (p < 0.0001, Chi-squared test). In contrast, with advancing gestation the rate of unsuccessful NT measurement because the crown–rump length (CRL) was greater than 84 mm significantly increased (p < 0.0001, Chi-squared test). Of the women who had had an earlier ultrasound, 42 (1.6%) had a missed miscarriage and 9 (0.3%) were over gestation at the time of the NT scan. These data suggest that when only the last menstrual period is known the optimum time to schedule a nuchal translucency measurement is at 12 to 13 weeks' gestation. Copyright © 2002 John Wiley & Sons, Ltd.