First-trimester free beta (hCG) screening for Down syndrome

Maternal serum free beta (hCG) levels are elevated (median 2·20 MOM) in the first trimester of pregnancy in 38 Down syndrome cases as compared with appropriate controls. This observation may form the basis for its use as a marker in screening for Down syndrome in the first trimester. Altered levels of the free beta analyte are observed in pregnancy conditions or complications other than Down syndrome.     

Simulating the fate and transport of TCE from groundwater to indoor air

This work provides an exploratory analysis on the relative importance of various factors controlling the fate and transport of volatile organic contaminants (in this case, TCE) from a DNAPL source zone located below the water table and into the indoor air. The analysis is conducted using the multi-phase compositional model CompFlow Bio, with the base scenario problem geometry reminiscent of a field experiment conducted by Rivett [Rivett, M.O., (1995), Soil–gas signatures from volatile chlorinated solvents: Borden field experiments. Groundwater, 33(1), 84–98.] at the Borden aquifer where groundwater was observed to transport a contaminant plume a substantial distance without vertical mass transport of the contaminant across the capillary fringe and into the vadose zone. Results for the base scenario model indicate that the structure of the permeability field was largely responsible for deflecting the groundwater plume upward towards the capillary fringe, permitting aqueous phase diffusion to transport the TCE into the vadose zone. Alternative permeability realizations, generated as part of a Monte Carlo simulation process, at times deflected the groundwater plume downwards causing the extended thickness of the saturated zone to insulate the vadose zone from exposure to the TCE by upward diffusive transport. Comparison of attenuation coefficients calculated using the CompFlow Bio and Johnson and Ettinger [Johnson, P.C. and Ettinger, R.A., (1991), Heuristic model for predicting the intrusion rate of contaminant vapors into buildings. Environmental Science and Technology, 25, 1445–1452.] heuristic model exhibited fortuitous agreement for the base scenario problem geometry, with this agreement diverging for the alternative permeability realizations as well as when parameters such as the foundation slab fracture aperture, the indoor air pressure drop, the capillary fringe thickness, and the infiltration rate were varied over typical ranges.     

The health sector gap in the southern Africa crisis in 2002/2003

The southern Africa crisis represents the first widespread emergency in a region with a mature HIV/AIDS epidemic. It provides a steep learning curve for the international humanitarian system in understanding and responding to the complex interactions between the epidemic and the causes and the effects of this crisis. It also provoked much debate about the severity and causes of this emergency, and the appropriateness of the response by the humanitarian community. The authors argue that the over-emphasis on food aid delivery occurred at the expense of other public health interventions, particularly preventative and curative health services. Health service needs were not sufficiently addressed despite the early recognition that ill-health related to HIV/AIDS was a major vulnerability factor. This neglect occurred because analytical frameworks were too narrowly focused on food security, and large-scale support to health service delivery was seen as a long-term developmental issue that could not easily be dealt with by short-term humanitarian action. Furthermore, there were insufficient countrywide data on acute malnutrition, mortality rates and performance of the public health system to make better-balanced evidence-based decisions. In this crisis, humanitarian organisations providing health services could not assume their traditional roles of short-term assistance in a limited geographical area until the governing authorities resume their responsibilities. However, relegating health service delivery as a long-term developmental issue is not acceptable. Improved multisectoral analytical frameworks that include a multidisciplinary team are needed to ensure all aspects of public health are dealt with in similar future emergencies. Humanitarian organisations must advocate for improved delivery and access to health services in this region. They can target limited geographical areas with high mortality and acute malnutrition rates to deliver their services. Finally, to address the underlying problem of the health sector gap, a long-term strategy to ensure improved and sustainable health sector performance can only be accomplished with truly adequate resources. This will require renewed efforts on part of governments, donors and the international community. Public health interventions, complementing those addressing food insecurity, were and are still needed to reduce the impact of the crisis, and to allow people to re-establish their livelihoods. These will increase the population's resilience to prevent or mitigate future disasters.     

Assessment of organochlorine pesticide residues in Atlantic Rain Forest fragments, Rio de Janeiro, Brazil

A superficial water quality survey in a watershed of the Paraíba do Sul River, the main water supply for the most populated cities of southeastern Brazil, was held in order to assess the impact of the expansion of agricultural activity in the near border of the Atlantic Rain Forest. The aim of this study was to investigate the presence of priority organochlorine pollutants in soils and superficial waters of Atlantic rainforest fragments in Teresópolis, Rio de Janeiro State. Soil sample preparations were compared by using ultrasound, microwave assisted extraction and Soxhlet extraction. Recoveries of matrix spiked samples ranged from 70 to 130%. Analysis of a certified soil material showed recoveries ranging from 71 to 234%. Although low concentrations of organochlorine residues were found in water and soil samples, this area is of environmental importance and concern, thus demanding a monitoring program of its compartments.     

应用人工湿地技术处理屠宰废水:设计与运行探讨

污水分散式处理有独特的优点,人工湿地是其中主要的方法,特别适合在农村地区因地制宜地处理生活污水,具有运行费用低、处理效果好的特点,在新农村环境建设中发挥了很大作用。但人工湿地用于污染程度高的行业废水处理国内比较少见。该文依据一项中德环保合作项目——人工湿地技术处理蕲春某屠宰厂废水的示范工程,对人工湿地建造有关的设计及运行管理问题进行总结与探讨。     

TUGAI: An Integrated Simulation Tool for Ecological Assessment of Alternative Water Management Strategies in a Degraded River Delta

The development of ecologically sound water allocation strategies that account for the needs of riverine ecosystems is a pressing issue, especially in semiarid river basins. In the Aral Sea Basin, a search for strategies to mitigate ecological and socioeconomic deterioration has been in process since the early 1990s. The Geographic Information System–based simulation tool TUGAI has been developed to support the policy determination process by providing a simple, problem-oriented method to assess ecological effects of alternative water management strategies for the Amudarya River. It combines a multiobjective water allocation model with simple, spatially explicit statistical and rule-based models of landscape dynamics. Changes in environmental conditions are evaluated by a fuzzy habitat suitability index for Populus euphratica, which is the dominant species of the characteristic riverine Tugai forests. Water management scenarios can be developed by altering spatiotemporal water distribution in the delta area or the amount of water inflow into the delta. Outcomes of scenario analysis are qualitative comparisons of the ecological effects of different options for a time period of up to 28 years. The given approach utilizes different types of knowledge, from quantitative hydrological data to qualitative local expert knowledge. The main purpose of the tool is to integrate the knowledge in a comprehensive way to make it available for discussions on alternative policies in moderated workshops with stakeholders. In this article, the modules of the tool, their integration, and three hypothetical scenarios are presented. Based on the experience gained when developing the TUGAI tool, we propose that the general framework can be transferred to other areas where tradeoffs in water allocation between the environment and other water users are of major concern. The potential for a simulation tool to structure and inform a complex resource management situation by involving local experts and stakeholders in the development of possible future scenarios will become increasingly valuable for transparent and participatory resource management.     

A WATER POLICY-LAND USE COMPUTER SIMULATION MODEL1

ABSTRACT: This paper describes the philosophy, algorithms, and implementation of a computer-oriented land use forecasting-water policy simulation model. The model is applicable to SMSA's organized on a census tract basis by counties. The forecasts are macro to the census tract level for industrial, residential, commercial and public land uses, and are dynamically altered by hypothesized water management policies. Modeling is based on an economic data base of the region, and is extremely flexible for the user. An example set of simulations is included for illustrative purposes.     

Choosing rewarding flowers; perceptual limitations and innate preferences influence decision making in bumblebees and honeybees

Flowers exhibit great intra-specific variation in the rewards they offer. At any one time, a significant proportion of flowers often contain little or no reward. Hence, foraging profitably for floral rewards is problematic and any ability to discriminate between flowers and avoid those that are less rewarding will confer great advantages. In this study, we examine discrimination by foraging bees among flowers of nasturtium, Tropaeolum majus. Bee visitors included carpenter bees, Xylocopa violacea, which were primary nectar robbers; honeybees, Apis mellifera, which either acted as secondary nectar robbers or gathered pollen legitimately and bumblebees, Bombus hortorum, which were the only bees able to gather nectar legitimately. Many flowers were damaged by phytophagous insects. Nectar volume was markedly lower in flowers with damaged petals (which were also likely to be older) and in flowers that had nectar-robbing holes. We test whether bees exhibit selectivity with regards to the individual flowers, which they approach and enter, and whether this selectivity enhances foraging efficiency. The flowers approached (within 2 cm) by A. mellifera and B. hortorum were non-random when compared to the floral population; both species selectively approached un-blemished flowers. They both approached more yellow flowers than would be expected by chance, presumably a reflection of innate colour preferences, for nectar standing crop did not vary according to flower colour. Bees were also more likely to accept (land on) un-blemished flowers. A. mellifera gathering nectar exhibited selectivity with regards to the presence of robbing holes, being more likely to land on robbed flowers (they are not able to feed on un-robbed flowers). That they frequently approached un-robbed flowers suggests that they are not able to detect robbing holes at long-range, so that foraging efficiency may be limited by visual acuity. Nevertheless, by using a combination of long-range and short-range selectivity, nectar-gathering A. mellifera and B. hortorum greatly increased the average reward from the flowers on which they landed (by 68% and 48%, respectively) compared to the average standing crop in the flower population. Overall, our results demonstrate that bees use obvious floral cues (colour and petal blemishes) at long-range, but can switch to using more subtle cues (robbing holes) at close range. They also make many mistakes and some cues used do not correlate with floral rewards.     

Degradation of 2,4,6-trinitrotoluene by selected helophytes

Four emergent plants (helophytes, synonyms emersion macrophytes, marsh plants, etc.) Phragmites australis, Juncus glaucus, Carex gracillis and Typha latifolia were successfully used for degradation of TNT (2,4,6-trinitrotoluene) under in vitro conditions. The plants took up and transformed more than 90% of TNT from the medium within ten days of cultivation. The most efficient species was Ph. australis which took up 98% of TNT within ten days. The first stable degradation products 4-amino-2,6-dinitrotoluene (4-ADNT) and 2-amino-4,6-dinitrotoluene (2-ADNT) were identified and analysed during the cultivation period. [14C] TNT was used for the detection of TNT degradation products and their compartmentalization in plant tissues after two weeks of cultivation. Forty one percent of 14C was detected as insoluble or bound in cell structures: 34% in roots and 8% in the aerial parts. These results open the perspective of using the above-mentioned plants for the remediation of TNT contaminated waters.