Microphagous ciliates in mesohaline Chesapeake Bay waters: Estimates of growth rates and consumption by copepods

Growth rates of microphagous ciliates (forms which feed primarily on picoplankton-sized prey) were estimated, along with rates of their consumption by copepods, in shipboard experiments conducted in the mesohaline portion of Chesapeake Bay, USA, under contrasting water column conditions in April, June, and August 1987. Estimates were based on temporal changes in cell densities in size-fractionated water samples incubated under in situ conditions. In April, at low temperatures (7 to 10°C) and with oxygen present throughout the water column, similar generation times of ca. 1 to 1.5 d were estimated for surface and deep water (24 m) ciliate populations. In June, water was anoxic below 12 m and a distinct anoxic microphage community grew at about twice the rate of the surface community with generation times of ca. 7 and 14 h, respectively. In August, bottom water was again anoxic, but the sameStrobilidium sp. dominated both surface and deep waters with low or no growth apparent in anoxic waters and a generation time of ca. 8 h in surface waters. Copepod (primarilyAcartia tonsa Dana nauplii) clearance rates for microphagous ciliates in surface waters were 0.11, 0.56, and 0.53 ml h^–1 copepod^–1 for April, June and August, respectively. Calculation of removal rates, based on average densities, indicated that from 34 to 200% of surface waters were cleared d^–1 of microphagous ciliates by copepods.     

European union system for the evaluation of substances: the second version

This publication presents major changes in the assessment of the risks of chemicals to human health and the environment as implemented in the second version of the European Union System for the Evaluation of Substances, EUSES 2.0. EUSES is a harmonised quantitative risk assessment tool for chemicals. It is the PC-implementation of the technical guidelines developed within the framework of EU chemical legislation for industrial chemicals and biocides. As such, it is designed to support decision making by risk managers in government and industry and to assist scientific institutions in the risk assessment for these substances. The development of EUSES 2.0 is a co-ordinated project of the European Chemicals Bureau, EU Member States and the European chemical industry. Several model concepts, the technical background and the user interface of EUSES have been improved considerably. Major changes in the environmental assessment such as the implementation of emission scenario documents for industrial chemicals and biocides, the addition of the marine risk assessment, the enhancement of the regional model to include global scales, and improvements in the secondary poisoning and environmental effects modelling will be discussed. The update of the human risk assessment module in EUSES focuses on the risk characterisation for both threshold and non-threshold substances with, among others, the introduction of assessment factors. The performance of EUSES is illustrated in an example showing the human and environmental risk assessment of a sanitation disinfectant for private use.     

A Concentric Analysis of the Impact of Urbanization on the Threatened European Tree Frog in an Agricultural Landscape

Abstract:  Pond-breeding amphibians are affected by site-specific factors and regional and landscape-scale patterns of land use. Recent anthropogenic landscape modifications (drainage, agriculture intensification, larger road networks, and increased traffic) affect species by reducing the suitable habitat area and fragmenting remaining populations. Using a robust concentric approach based on permutation tests, we evaluated the impact of recent landscape changes on the presence of the endangered European tree frog ( Hyla arborea ) in wetlands. We analyzed the frequency of 1 traffic and 14 land-use indices at 20 circular ranges (from 100-m up to 2-km radii) around 76 ponds identified in western Switzerland. Urban areas and road surfaces had a strong adverse effect on tree frog presence even at relatively great distances (from 100 m up to 1 km). When traffic measurements were considered instead of road surfaces, the effect increased, suggesting a negative impact due to a vehicle-induced effect. Altogether, our results indicate that urbanization and traffic must be taken into account when pond creation is an option in conservation management plans, as is the case for the European tree frog in western Switzerland. We conclude that our easy-to-use and robust concentric method of analysis can successfully assist managers in identifying potential sites for pond creation, where probability of the presence of tree frogs is maximized.     

1999年委内瑞拉阿维拉山北坡入海型泥石流

委内瑞拉阿维拉山呈东一西走向，北坡濒临加勒比海．１９９９年１２月１６日，阿维拉山北坡２０多条沟谷暴发泥石流，使沿海的城镇、村庄、港口、公路及各种设施遭到毁灭性破坏，造成数万人死亡，直接经济损失超过刀亿美元．泥石流发生在森林植被良好的山区，具低频率和群发性特征，规模大，直接入海．分析这次泥石流灾害，对我国的防灾减灾工作具有启示意义．     

Continuous-flow column study of reductive dehalogenation of PCE upon bioaugmentation with the Evanite enrichment culture

A continuous-flow anaerobic column experiment was conducted to evaluate the reductive dechlorination of tetrachloroethene (PCE) in Hanford aquifer material after bioaugmentation with the Evanite (EV) culture. An influent PCE concentration of 0.09 mM was transformed to vinyl chloride (VC) and ethene (ETH) within a hydraulic residence time of 1.3 days. The experimental breakthrough curves were described by the one-dimensional two-site-nonequilibrium transport model. PCE dechlorination was observed after bioaugmentation and after the lactate concentration was increased from 0.35 to 0.67 mM. At the onset of reductive dehalogenation, cis-dichloroethene (c-DCE) concentrations in the column effluent exceeded the influent PCE concentration indicating enhanced PCE desorption and transformation. When the lactate concentration was increased to 1.34 mM, c-DCE reduction to vinyl chloride (VC) and ethene (ETH) occurred. Spatial rates of PCE and VC transformation were determined in batch-incubated microcosms constructed with aquifer samples obtained from the column. PCE transformation rates were highest in the first 5 cm from the column inlet and decreased towards the column effluent. Dehalococcoides cell numbers dropped from approximately 73.5% of the total Bacterial population in the original inocula, to about 0.5% to 4% throughout the column. The results were consistent with estimates of electron donor utilization, with 4% going towards dehalogenation reactions.     

First-trimester diagnosis of Bartsocas–Papas syndrome (BPS) by transvaginal ultrasound: case report and review of the literature

Initially described in 1972, Bartsocas–Papas syndrome (BPS) is an autosomal recessively inherited disorder combining multiple pterygia, ankyloblepharon, cleft lip and palate, filiform bands between the jaws, syndactyly, and other anomalies. Although described as lethal, review of the literature reveals three individuals who survived into childhood with this condition. We describe a fourth surviving patient and what we believe to be the first prenatal diagnosis of BPS in the first trimester. Copyright © 2003 John Wiley & Sons, Ltd.     

Implementing computer-based automation in the office: A study of experienced stress

This study focuses on the impact of previous experience with automation implementations on experienced stress associated with different work aspects, following the introduction of computer-based office automation. One hundred and ninety-one full-time secretaries at a large university in Canada completed questionnaires related to stress perception and prior experience with office automation. Results indicated that those without previous experience reported higher levels of experienced stress associated with work content aspects such as task difficulty and interest in the task, whereas those with prior experience reported greater problems with contextual aspects such as training and instruction. These findings are discussed in the context of research on ‘technological change as a source of organizational and occupational stress’.     

TILE RATIONALE FOR OHIO'S DETERGENT PHOSPHORUS BAN1

ABSTRACT: Ohio signed into law a detergent phosphorus ban on March 26, 1988. This law limits the elemental phosphorus content of household laundry detergents to 0.5 percent in all 35 Lake Erie counties in Ohio by 1990. Ohio's detergent phosphorus ban will help non-compliant municipal wastewater treatment plants achieve compliance with the 1 mg/L effluent phosphorus standard. By limiting the phosphorus content of household laundry detergents, Ohio will also benefit from less phosphorus entering surface waters from combined sewer overflows, communities with treatment plant bypasses, and riparian homes with septic tanks. This is important because most of the phosphorus in laundry detergents is in the bioavailable form and Ohio's Lake Erie shoreline is particularly sensitive to Cladophora problems. When viewed in conjunction with reduced chemical costs for phosphorus removal and savings in sludge disposal costs, Ohio's detergent phosphorus ban is a pragmatic component of an international phosphorus management strategy to protect the Great Lakes.