Probabilistic biokinetic modelling of radiocaesium uptake in Arctic seal species: verification of modelled data with empirical observations

The necessity to provide information about radionuclide concentrations in Arctic marine species has been heightened in recent years due to a number of accidents in Arctic regions involving nuclear vessels and the presence of a large number of potential radioactive contamination sources. The provision for such information is largely dependent on the use of radionuclide uptake and transfer models. The uptake of radionuclides in Arctic seal species in this study has been modelled using a probabilistic biokinetic approach. In this paper, model results are compared with empirical data from relevant samples taken within the Arctic region. Results indicate that the model performs well when estimating concentrations of (137)Cs in two seal species for both median values and reproduction of the distribution of data values, but not as well for a third seal species. Likely factors affecting the results are the probability density functions used for the input parameters.     

Matching and mismatching stable isotope (δ13C and δ15N) ratios in fin and muscle tissue among fish species: a critical review

Using non-lethal tissue sampling for stable isotope analysis has become standard in many fields, but not for fishes, despite being desirable when species are rare or protected, when repeated sampling of individuals is required or where removal may bias other analyses. Here, we examine the utility of fish dorsal fin membrane as an alternative to muscle for analyzing δ¹³C and δ¹⁵N ratios in two reef fish species (blue cod Parapercis colias and spotty Notolabrus celidotus) that have differing feeding modes. Both species exhibited evidence of size-based feeding from fin δ¹⁵N values, but not from muscle. Blue cod fin δ¹⁵N increased steadily throughout the sampled size range (213–412 mm fork length), whereas spotty exhibited a distinct ontogenetic diet shift at approximately 120–140 mm fork length after which size-based feeding did not occur. Fin membrane was higher than muscle in δ¹³C in both species and in δ¹⁵N for blue cod, but fin δ¹⁵N was lower than muscle in spotty. The δ¹³C and δ¹⁵N fin–muscle offsets were constant in spotty regardless of size, while in blue cod, δ¹³C was constant with fish size, but δ¹⁵N offsets increased with increasing fish size. Non-lethal sampling utilizing fin tissue can be employed to estimate stable isotope values of muscle in fishes, but it is necessary to assess relationships among tissues and the effects of fish size on isotope values a priori for each species studied. Our data indicated that fin membrane may be a more sensitive tissue than muscle for detecting size-based feeding in some fish species using stable isotopes. A critical literature review revealed inconsistencies in tissue types tested, little understanding of tissue-specific trophic shift or turnover rates, and pseudo-replicated analyses leading to erroneous postulating of 1:1 relationships between tissues.     

Measuring mucus thickness in reef corals using a technique devised for vertebrate applications

A method previously used to measure thickness of the surface mucus layer (SML) of the mammalian gastrointestinal tract has been applied to the SML of reef corals. It involves manual measurement of mucus thickness using a micromanipulator and fine glass needle (micropipette) and is non-destructive to the coral, meaning that repeated measurements can be taken. A measurable mucus layer was recorded in all cases in the study, which comprised 450 individual thickness measurements from four coral species. Mucus thickness ranged from 145 to 700 μm. Thus, whatever dynamic processes control mucus synthesis, secretion to the tissue surface and subsequent release into the water column, a continuous mucosal barrier is maintained. A change in SML thickness was recorded as a response to aerial exposure during the natural tidal cycle and to solar exposure-induced bleaching, although the response due to bleaching varied between two studied species. The technique is rapid, cost-effective and a simple means of assessing coral SML thickness, a variable that shows significant variation in relation to environmental conditions and is likely to be an important health indicator in these organisms.     

Adsorption and degradation of the weak acid mesotrione in soil and environmental fate implications

The ability of soils to adsorb and degrade pesticides strongly influences their environmental fate. This paper examines the adsorption and degradation of a weak acid, a new herbicide mesotrione 12-[4-(methylsulfonyl)-2-nitrobenzoyl]-1,3-cyclohexanedione], in 15 different soils from Europe and the USA. Experiments were conducted to understand the influence of soil properties, covering a wide range of soil textures, soil pH values (4.4 to 7.5), and organic carbon contents (0.6 to 3.35%). Mesotrione adsorption (Kd values ranged from 0.13 to 5.0 L/kg) was primarily related to soil pH, and to a lesser extent by percent organic carbon (%OC). As soil pH rose. mesotrione Kd values got smaller as mesotrione dissociated from the molecular to anionic form. Mesotrione degradation (half-lives ranged from 4.5 to 32 d) was also related to soil pH, getting shorter as soil pH rose. Simple regression of mesotrione adsorption against soil pH and %OC and against degradation provided a close fit to the data. The correlation between mesotrione adsorption and degradation means that Kd and half-life values are only relevant for use in environmental fate assessment if these values are "paired" for the same soil pH and %OC. The implications were as illustrated for leaching, raising important issues about combining pesticide adsorption and degradation behavior in environmental fate assessments.     

Rapid prenatal diagnosis of sickle cell diseases using oligonucleotide ligation assay coupled with laser-induced capillary fluorescence detection

Prenatal diagnosis of sickle cell diseases has been available for several years, and our laboratory has performed over 1000 prenatal diagnoses. However, currently available techniques are labor-intensive and time-consuming, and thus the diagnosis is delayed, making the mother's decision difficult. We describe a rapid, high-throughput technique based on the ligation assay coupled with automated capillary fluorescence detection. This new approach allows the diagnosis of both Hgb S and Hgb C to be available in a few hours. We have utilized this technique in 30 prenatal diagnoses and found it to be in complete agreement with the standard diagnoses. Copyright © 2002 John Wiley & Sons, Ltd.     

Improved protection for children in forward-facing restraints during side impacts

OBJECTIVE: This study aims to determine the potential for improved child occupant protection in side impacts that can be obtained using rigid and semi-rigid anchorage systems and the addition of energy-absorbing padding in the side structures of child restraints. METHODS: This study uses a comprehensive set of simulated side impacts to evaluate the potential for improved side impact protection in forward-facing child restraints. Factors investigated included methods of anchoring the restraint to the vehicle, energy-absorbing materials in the side structure of restraints, and design features of the restraints such as side wing geometry and seat belt routing. RESULTS: The results show clearly that completely rigid lower attachment of restraints offers the potential for great reductions in head injury risk, which anchorage systems employing a combination of a rigid anchorage bar and webbing attached to a child restraint cannot match. The addition of energy absorbing material in the side structure of restraint systems is effective when the head is fully contained within an adequately designed side wing structure. For restraints anchored by seat belts and loop style semi rigid anchorage straps, belt routing has the potential to significantly affect occupant head excursion. CONCLUSIONS: The results suggest that current child restraint standards and consumer testing protocols do not adequately encourage best practice design of child restraints for side impact protection.     

Rapid vegetation regeneration in a seriously degraded Rhanterium epapposum community in northern Kuwait after 4 years of protection

A study was carried out in northern Kuwait to investigate vegetation recovery in sandy depressions in the Sabriya oilfield ('Sabriya-IN'), 4 years after it was completely protected from livestock grazing and other anthropogenic activities which have largely depleted the dwarf shrub vegetation. This vegetation was compared with that in seriously overgrazed depressions outside the oilfield ('Sabriya-OUT'), where negative influences persist, and with a sandy site in central Kuwait which has been protected for over 20 years ('Sulaibiya'). There has been a striking recovery of the dwarf shrub vegetation in Sabriya-IN during the 4 years, with cover values of shrubs as high as at Sulaibiya. Rhanterium epapposum has been the main species to benefit from protection. However, the shrubs have not regenerated from seed, but rather from underground stumps that have probably remained in the soil for decades. Cover values of the annual flora at Sabriya-IN were very similar to those at Sulaibiya, and they were significantly higher than at Sabriya-OUT. However, it appears that some species may have disappeared or become extremely rare at Sabriya-IN when compared with Sulaibiya, as Sabriya-IN and Sabriya-OUT are remarkably similar floristically. Despite the impressive regeneration of the dwarf shrub vegetation at Sabriya-IN, which contradicts the view that vegetation recovery is a slow process in desert ecosystems, it is important to consider what the natural vegetation was in this part of the world. It is suggested that the region was once dominated by an open Acacia woodland, in which perennial grasses comprised most of the ground layer, and that the current dwarf shrub vegetation is a response to decades, if not centuries, of moderate to heavy grazing.     

Risk-sensitive foraging in common shrews (Sorex araneus L.)

Summary Risk-sensitive foraging theory predicts that predators which face starvation if there is a temporary shortfall in their food supply should choose feeding sites on the basis of variation in as well as mean expected reward rate. For a given mean reward rate they should choose high variance feeding sites (be risk-prone) if they are running below energy requirement, but low variance sites (be risk-averse) if they are running above.Common shrews presented with a choice between constant and variable feeding stations were more likely to visit the variable station when they were running below energy requirement and more likely to visit the constant station when they were running above. However, the tendency towards risk-aversion above requirement was greater than that towards risk-proneness below.When all shrews were considered together, the probability of visiting the variable station correlated negatively and continuously with intake relative to requirement.     

Designing metrics that fit: Rethinking corporate environmental performance measurement systems

If you don't measure it, you can't manage it. Over the past decade, many companies have recognized this need to track environmental performance. Failure to plan metrics systems to fit organizational needs, work flows, and culture has left many companies with costly and ineffective environmental performance measurement systems. This article presents numerous practical steps for designing effective metrics systems which avoid common pitfalls.