Toxicity and attraction effects produced byMorinda citrifolia fruits on theDrosophila melanogaster complex of species

Summary The ripe fruit of the Indian mulberry,Morinda citrifolia, is the host plant forDrosophila sechellia but is highly toxic for three closely related species (D. melanogaster, D. simulans, D. mauritiana). A simple bioassay is described with which a clear dose response to the fruit was found for these species. Significant differences in reactivity to the ripe fruit were found among species. Tested strains ofD. simulans andD. mauritiana adults were more sensitive to the toxic properties of the fruit thanD. melanogaster. A marked intraspecific variability was shown inD. melanogaster. Reciprocal interspecific hybridizations betweenD. sechellia andD. mauritiana suggested an autosomal dominant control of resistance. MoreoverD. melanogaster intraspecific crossings suggested the influence of an additional X-linked factor. Responses of flies toMorinda fruit in different states were tested in a T olfactometer. The less resistant strains ofDrosophila generally showed less preference for the ripe fruit.     

Assessment of the Water Quality and Ecosystem Health of the Great Barrier Reef (Australia): Conceptual Models

Run-off containing increased concentrations of sediment, nutrients, and pesticides from land-based anthropogenic activities is a significant influence on water quality and the ecologic conditions of nearshore areas of the Great Barrier Reef World Heritage Area, Australia. The potential and actual impacts of increased pollutant concentrations range from bioaccumulation of contaminants and decreased photosynthetic capacity to major shifts in community structure and health of mangrove, coral reef, and seagrass ecosystems. A detailed conceptual model underpins and illustrates the links between the main anthropogenic pressures or threats (dry-land cattle grazing and intensive sugar cane cropping) and the production of key contaminants or stressors of Great Barrier Reef water quality. The conceptual model also includes longer-term threats to Great Barrier Reef water quality and ecosystem health, such as global climate change, that will potentially confound direct model interrelationships. The model recognises that system-specific attributes, such as monsoonal wind direction, rainfall intensity, and flood plume residence times, will act as system filters to modify the effects of any water-quality system stressor. The model also summarises key ecosystem responses in ecosystem health that can be monitored through indicators at catchment, riverine, and marine scales. Selected indicators include riverine and marine water quality, inshore coral reef and seagrass status, and biota pollutant burdens. These indicators have been adopted as components of a long-term monitoring program to enable assessment of the effectiveness of change in catchment-management practices in improving Great Barrier Reef (and adjacent catchment) water quality under the Queensland and Australian Governments’ Reef Water Quality Protection Plan.     

Nitrogen- vs. phosphorus-based dairy manure applications to field crops: nitrate and phosphorus leaching and soil phosphorus accumulation

Management of animal manures to provide nutrients for crop growth has generally been based on crop N needs. However, because manures have a lower N/P ratio than most harvested crops, N-based manure management often oversupplies the crop-soil system with P, which can be lost into the environment and contribute to eutrophication of water bodies. We examined the effects of N- vs. P-based manure applications on N and P uptake by alfalfa (Medicago sativa L.), corn (Zea mays L.) for silage, and orchardgrass (Dactylis glomerata L.), leaching below the root zone, and accumulation of P in soil. Treatments included N- and P-based manure rates, with no nutrient input controls and inorganically fertilized plots for comparison. Nitrate concentrations in leachate from inorganic fertilizer or manure treatments averaged 14 mg NO(3)-N L(-1), and did not differ by nutrient treatment. Average annual total P losses in leachate did not exceed 1 kg ha(-1). In the top 5 cm of soil in plots receiving the N-based manure treatment, soil test P increased by 47%, from 85 to 125 mg kg(-1). Nitrogen- and P-based manure applications did not differ in ability to supply nutrients for crop growth, or in losses of nitrate and total P in leachate. However, the N-based manure led to significantly greater accumulation of soil test P in the surface 5 cm of soil. Surface soil P accumulation has implications for increased risk of off-field P movement.     

Investigation of performance enhancement of solar still incorporated with Gallus gallus domesticus cascara as sensible heat storage material

In this research work, the conventional single slope still (CSS) with egg shells of breed Gallus gallus domesticus cascara as sensible heat storage (SHS) material are studied experimentally to enhance the yield. In this experimental investigation, the proposed single slope still (PSS) with SHS material was made in comparison with the CSS to evaluate the productivity of fresh water under the same ambient conditions. Comparatively, this PSS has higher thermal conductivity than the CSS. The yield obtained from the PSS is 2.46 L/m², while the yield from the CSS is 2.07 L/m². The average rate at which the rise of output fresh water obtained from the PSS is 18% more than the fresh water output obtained from the CSS. The daily energy efficiency of the PSS is 26.07%, and for the CSS, it is only 22.25%. The daily exergy efficiency of the PSS is 2.36%, and for the CSS, it is only 1.67%. Since using the egg shell will employ as organic waste management and modification in this still is economical, less initial, and maintenance cost.

     

Conditions for successful environmental justice mobilizations: an analysis of 50 cases

ABSTRACT

The environmental justice (EJ) literature can benefit from comparative analysis that helps to identify conditions for more and less successful outcomes. A data set of 50 EJ cases in the U.S. was developed with high and low remediation as the outcome. Causal conditions were selected on theoretical grounds, and included five mobilizing strategies (local and state government coalitions, federal government attention, civil disobedience, litigation, and national NGO support) and three general conditions (absence of industry counter-mobilization, presence of water pollution, and proposed or new siting). Qualitative comparative analysis and other analyses indicated that all causal conditions were found in the high-remediation cases but that some conditions (water pollution and local–state coalitions) were more consistently associated with the high-remediation outcome. The analysis points to the value of systematic studies of the factors that affect local EJ outcomes and to the need for better case study collections.     

Drought effects on the Iranian economy: a computable general equilibrium approach

Environment, Development and Sustainability - In the last two decades, recurring drought becomes a challenge for Iran’s economy, which is located in a drought-prone area, and it has been...     

Job embeddedness and voluntary turnover in the face of job insecurity

Two important contributions to the understanding of voluntary turnover are the ideas that employees become embedded in a net or web of restraining forces on- and off-the-job and that they experience varying degrees of control and desire that yield proximal withdrawal states explaining turnover motivations. We build on these ideas in two multi-wave studies to study job insecurity, one of the most common work stressors and top concerns among employees around the world. Study 1 demonstrates that job search mediates the positive relationship between job insecurity and voluntary turnover, and that employees higher in on-the-job embeddedness are less likely to search for jobs despite job insecurity. Study 2 demonstrates that turnover intention mediates the positive relationship between job insecurity and voluntary turnover, and that employees higher in on-the-job embeddedness are less likely to contemplate quitting despite job insecurity. However, off-the-job embeddedness had opposite interactive effects, exacerbating the relationship of job insecurity with turnover.     

SIMULATING FLOW IN REGIONAL WETLANDS WITH THE MODFLOW WETLANDS PACKAGE1

ABSTRACT: As part of the Comprehensive Everglades Restoration Plan (CERP), various water supply projects have been proposed in a region located between the Miami metropolitan area and the extensive regional wetland systems that are part of the Everglades or remnant Everglades. A ground water flow model of the surficial aquifer within northern Miami‐Dade County was constructed using MODFLOW to evaluate the effects of these projects on water levels in the wetlands and the underlying surficial aquifer. The new Wetlands package was used to conjunctively simulate overland flow through these wetlands and the shallow ground water system. Comparisons of simulated to measured ground water levels and wetland stages were very satisfactory, where computed and measured water levels agreed within 0.5 ft over most of the period of record at nearly all of the monitoring sites. Temporal trends in water levels were also replicated. It was concluded that the assumptions and methodologies inherent to the Wetlands package were suitable for simulating regional wetland hydrology within the Everglades area.