Economic incentives drive the conversion of agriculture to aquaculture in the Indian Sundarbans: Livelihood and environmental implications of different aquaculture types

Expansion of aquaculture in the Sundarbans Biosphere Reserve (SBR) is irreversibly replacing agricultural land and the drivers of this change are disputed. Based on in-depth interviews with 67 aquaculture farmers, this paper characterizes major aquaculture types in the SBR, their impacts, and identifies drivers of conversion from agricultural land. Aquaculture types included traditional, improved-traditional, modified-extensive, and semi-intensive systems. Extensive capture of wild shrimp larvae is environmentally harmful but constitutes an important livelihood. Semi-intensive aquaculture of exotic shrimp (Litopenaeus vannamei) has much higher unit-area profitability than other types but involves greater financial risk. Profitability is the main driver for the transition from agriculture, but environmental factors such as lowered crop yields and cyclone impacts also contributed. Many conversions from agriculture to aquaculture are illegal according to the stakeholders. Existing legislation, if enforced, could halt the loss of agriculture, while the promotion of improved-traditional aquaculture could reduce the demand for wild seed.     

Transfer of selenium from prey to predators in a simulated terrestrial food chain

Little is known about the accumulation and effects of selenium in reptiles. We developed a simplified laboratory food chain where we fed commercial feed laden with seleno-D,L-methionine (30 microg/g dry mass) to crickets (Acheta domestica) for 5-7 d. Se-enriched crickets (approximately 15 microg/g Se [dry mass]) were fed to juvenile male and female lizards (Sceloporus occidentalis) for 98 d while conspecifics were fed uncontaminated crickets. Lizards fed contaminated prey accumulated Se concentrations ranging from 9.3 (in female carcass) to 14.1 (in female gonad) microg/g compared to <1.5 microg/g in tissues of controls. Female gonad concentrations approached the highest of thresholds for reproductive toxicity in oviparous vertebrates. However, we observed no consistent effect of dietary treatment on sublethal parameters or survival. Our simplified food chain proved to be an ecologically relevant method of exposing lizards to Se, and forms the foundation for future studies on maternal transfer and teratogenicity of Se.     

Living the green city: Freiburg's Solarsiedlung between narratives and practices of sustainable urban development

The solar settlement (Solarsiedlung) in Freiburg, Germany, has been widely hailed as an eco-city or green city neighbourhood and a blueprint for sustainable urban development. However, as there is a noticeable lack of critical analysis of what constitutes Solarsiedlung as an “eco-city”, this paper studies narratives and practices of sustainable urban development. First, we look at Solarsiedlung as a best-practice model – a narrative that was produced and perpetuated by architects, urban planners, investors and academics celebrating this neighbourhood as a technologically leapfrogging, economically sound and socially integrated project. Second, we explore the everyday practices and lived experience of the residents in Solarsiedlung. Bringing together these two perspectives, we contribute to a more comprehensive understanding and critical reading of the interplay between the ecological, economic and social dimensions of sustainable development as seen from different viewpoints. Findings indicate that Solarsiedlung as a best-practice model is embedded in growth-oriented neoliberal strategies that are in conflict with the everyday practices and lived experience of the residents. Our findings put into question the widely assumed transferability of best-practice models in sustainable urban development.     

Digital PCR: a powerful new tool for noninvasive prenatal diagnosis?

Recent reports have indicated that digital PCR may be useful for the noninvasive detection of fetal aneuploidies by the analysis of cell-free DNA and RNA in maternal plasma or serum. In this review we provide an insight into the underlying technology and its previous application in the determination of the allelic frequencies of oncogenic alterations in cancer specimens. We also provide an indication of how this new technology may prove useful for the detection of fetal aneuploidies and single gene Mendelian disorders. Copyright © 2008 John Wiley & Sons, Ltd.     

Emissions of isoprene,monoterpene and short-chained carbonyl compounds from Eucalyptus spp. in southern Australia

Eucalypts are among the highest emitters of biogenic volatile organic compounds, yet there is relatively little data available from field studies of this genus. Emissions of isoprene, monoterpenes and the short-chained carbonyls formaldehyde, acetaldehyde and acetone were determined from four species (Eucalyptus camaldulensis, Eucalyptus globulus, Eucalyptus grandis, and Eucalytpus viminalis) in Australia. A smaller comparative study was conducted on E. camaldulensis in south-eastern Australia. Carbonyl emissions, reported here for the first time from eucalypts, were generally comparable with rates reported for other species, with diurnal emissions peaking at about 4, 75 and 34 nmol m^?2 min^?1 for acetone, formaldehyde and acetaldehyde respectively. There was wide variation in diurnal isoprene and monoterpene emissions between species, but under standard conditions, isoprene emissions were much lower than previous reports. Conversely, standard emission rates of monoterpenes were as much as six times greater than previous reports for some species. Emission of each carbonyl was correlated with its ambient concentration across different species, but more weakly related to temperature. Acetaldehyde emission in particular was significantly correlated with transpiration, but not with sap flow or with ethanol concentrations in xylem sap, suggesting fermentation within the leaf and stomatal conductance are primary controlling processes. Differences in acetaldehyde exchange velocities between sites, in addition to transpiration differences, suggest stomata may indeed exert long term emission regulation, in contrast to compounds for which no biological sink exists.     

Sensitivity of SCS Models to Curve Number Variation1

ABSTRACT: The Soil Conservation Service (SCS) models, including the TR-20 computer program and the simplified methods in TR-55, are widely used in hydrologic design. The runoff curve number (CN), which is an important input parameter to SCS models, is defined in terms of land use tretments, hydrologic, condition, antecedent soil moisture, and soil type. The objective of this study was to evaluate the sensitivity of the SCS models to errors in CN estimates. The results show that the effects of CN variation decrease as the design rainfall depth increases, such as for the larger storm events. The value and use of the sensitivity curves are demonstrated using a comparison of Landsat and conventionally derived curve numbers for three watersheds in Pennsylvania.     

PARAMETER ESTIMATION IN HYDROLOGY: THE STATE OF THE ART1

ABSTRACT A detailed review of current methods and criteria used in parameter estimation in hydrology is presented. The effect of errors in the data set and the effect of interactions between methods of analysis, criteria, data set errors, and modeling assumptions are reviewed and discussed briefly. It is concluded that study of techniques, criteria, data set errors and particularly interactions between these, is essential to further progress in hydrologic modeling.     

New national parks for Scotland: coalitions in conflict over the allocation of planning powers in the Cairngorms

The introduction of national parks in areas where existing authorities have traditionally been responsible for developing policies, preparing plans and making decisions on development proposals, can be a threat to longstanding interests. This paper explores this problem by examining the struggle for control of planning in one of Scotland's first national parks, the Cairngorms. Recent research (McCarthy et al., 2002 McCarthy J Lloyd G Illsley B (2002) National parks in Scotland: balancing environment and economy Research briefing European Planning Studies 10 (5) pp. 665–670 [Web of Science ®] [Google Scholar]) has established the policy context for this investigation. Informed by research focusing on the consultation process which led to the establishment of the national park, this paper analyzes how alternative approaches to the allocation of planning powers were captured in competing storylines, around which polarized coalitions of interest formed. Opening such insights into the considerations that shape institutional design—a combination of contested problem framing and straightforward political struggles over the locus of regulatory power—starkly reveals the challenges to the new park authority as it seeks to establish consensus between conflicting interests.