Ovarian activity of Drosophila melanogaster meigen (diptera), during a chronic intoxication with four fungicides: Anatomical and cytological study

Abstract

Two types of reactions were observed on the alteration of Drosophila vitellogenesis by the four fungicides used in this study. Dithane®M45 resulted in stimulation associated with egg retention. However, the other three fungicides (Benlate®, Bouillie bordelaise® and Euparène®) resulted in inhibition to a varying degree. Although the inhibition was comparatively limited due to Benlate® it induced an egg retention. The inhibition was very high due to Bouillie bordelaise® and Euparène®. With Bouillie bordelaise® an egg retention occured together with the reduction of vitellogenesis and caused an increase in the rate of the follicle resorption. The latter depended on the duration of treatment. With Euparène®, no egg retention was observed and the toxicity was only noticed on vitellogenesis.     

Using a Mass Balance Model to Evaluate Groundwater Budget of Seawater‐Intruded Island Aquifers1

Jang, Cheng‐Shin, Chen‐Wuing Liu, Shih‐Kai Chen, and Wen‐Sheng Lin, 2011. Using a Mass Balance Model to Evaluate Groundwater Budget of Seawater‐Intruded Island Aquifers. Journal of the American Water Resources Association (JAWRA) 48(1): 61‐73. DOI: 10.1111/j.1752‐1688.2011.00593.x Abstract: The study developed a mass balance model to evaluate the groundwater budget of seawater‐intruded island aquifers using limited available data. The Penghu islands were selected as a study area. As sparse observed data were available in the islands, methods of combining water and chloride balances were used to determine the amounts of groundwater pumping, seawater intrusion, aquifer storages, and safe yields in the shallow and deep aquifers. The groundwater budget shows that seawater intrusion to freshwater aquifers was 1.38 × 10⁶ and 0.29 × 10⁶ m³/year in the shallow and deep aquifers, respectively, indicating that the seawater intrusion is severe in the both aquifers. The safe yield of the shallow aquifer was 14.56 × 10⁶ m³/year in 2005 which was four times higher than that of the deep aquifer (3.70 × 10⁶ m³/year). However, the annual pumping amounts in the shallow and deep aquifers were 4.77 × 10⁶ and 3.63 × 10⁶ m³/year, respectively. Although the safe yield of the shallow aquifer is enough for all water resources demands, only 55% of exploitation amount was extracted from the shallow aquifer due to its poor water quality. Groundwater exploitation in the deep aquifer should be significantly reduced and regulated by a dynamic management of pumping scheme because the annual pumping amounts are close to the safe yield and seawater intrusion occurs continually. Additionally, to alleviate further aquifer salination, at least half of the current annual groundwater abstraction should be reduced.     

Applying Zonation Methods and Tabu Search to Improve the Ground‐Water Modeling1

Abstract: An optimization procedure combining zonation methods with the Tabu Search method is proposed to identify the spatial distribution of hydraulic conductivity field. Three zonation methods, Voronoi diagram (VD), multiplicatively weighted Voronoi diagram (MWVD), and pattern zonation are adopted for the parameterization purposes. With the consideration of the homogeneity and the heterogeneity, there are four spatial distributions of hydraulic conductivity designed to test whether the parameter structure can be successfully identified. The fitting residual error is first considered to determine an adequate number of zones without over parameterization. Then, the parameter uncertainty is evaluated the decision of the number of zones. The results indicate that the MWVD performs better than other two methods because the MWVD has better flexibility in describing the zonal boundaries with small number of decision variables.     

Analysis of Extreme Summer Rainfall Using Climate Teleconnections and Typhoon Characteristics in South Korea1

Abstract: It is now widely acknowledged that climate variability modulates the frequency of extreme hydrological events. Traditional methodologies for hydrologic frequency analysis are not devised to account for variation in the exogenous teleconnections. Flood frequency analysis is further plagued by the assumptions of stationary in the causal structure as well as ergodicity. Here, we propose a dynamical hierarchical Bayesian analysis to account for exogenous forcing that govern the summer season rainfall. The precursors for Korean summer rainfall at different frequencies are identified utilizing wavelet and independent component analyses. The sea surface temperatures, the ensemble of rainfall predictions by General Circulation Model, in addition to the typhoon attributes were found to have direct correlation with extreme rainfall events and were used as inputs to the logistic regression model. The model parameters are estimated using Markov Chain Monte Carlo and the resulting posterior distributions associated with individual inputs are analyzed to advance our understanding of the spatiotemporal impact of the teleconnections. Eight rainfall stations throughout Korea are considered in this analysis. We demonstrate that the probability of occurrence of extreme events could be successfully projected at a 90% rate of correct classification of extreme events.     

Fecal Coliform Export From Four Coastal North Carolina Areas1

Abstract: Fecal coliform (FC) bacteria in coastal waters impair the use of these waters for shellfish harvesting and recreation. This study was designed to quantify and compare FC levels and export in two coastal watersheds with different land uses. Continuous monitoring of rainfall and discharge at three sites in the Jumping Run Creek watershed and one site in the Pettiford Creek watershed were conducted during a 4.5‐year period. Primary land use in the drainage area of one of the three Jumping Run Creek sites is low density industrial, while the other two are residential. Land use in the Pettiford Creek watershed is managed national forest. Nonstorm or base‐flow grab and flow‐proportional storm‐event samples were collected and analyzed for turbidity, conductivity, suspended sediment, nitrogen, phosphorus, and FC. Geometric mean FC levels for the Jumping Run Creek monitoring sites ranged from 593 to 2,096 mpn/100 ml, while the mean level at the Pettiford Creek site was 191 mpn/100 ml. Levels of most other parameters were greater in storm discharge from the Jumping Run Creek sites as compared to Pettiford Creek indicating that pollutant export from a watershed increases with development. Statistical analysis of the monitoring data suggested that FC levels in stormwater samples consistently increased with storm rainfall, but were not consistently correlated with any other parameter, including total suspended solids. Multivariate analysis indicated that the weekly FC export for each of the four sites was lowest during the December‐February quarter. Export was highest during the spring and summer at the Jumping Run Creek sites, while for the Pettiford Creek site, FC export was highest during September‐November. The cause of the seasonal variability was unknown but was thought to be associated with human activity in the watersheds.     

Life after the layoff: getting a job worth keeping

The competitive environment of business today makes corporate layoffs an organizational reality, and losing one's job can be a highly stressful experience. We propose and test a model that places objective underemployment and subjective underemployment in a causal sequence between organizational actions and employees' restoration of equilibrium by obtaining jobs worth keeping. We longitudinally examine relationships between layoff fairness, workers' stress symptoms and appraisal, and subsequent employment outcomes among 149 laid‐off technical employees over the course of one year. Structural equation model results support seven of nine hypothesized paths, and demonstrate discriminant validity between and mediational properties of objective and subjective underemployment. Findings also reveal the important role that employees' perceptions and subjective assessments play in successfully returning to pre‐job loss equilibrium following displacement. Copyright © 2008 John Wiley & Sons, Ltd.