Prenatal diagnosis and management of twin pregnancies complicated by a co-existing molar pregnancy

Recent advances in ultrasound and molecular genetics have increased our understanding and hence enhanced the perinatal management of complete and partial hydatidiform mole. By contrast, the management of a twin pregnancy combining a normal pregnancy with a normal fetus and a complete hydatidiform mole (CHM) remains complex and controversial due to conflicting data from different parts of the world. The aim of this review is to analyse the international literature on twin pregnancies that include a mole, present the complications and outcome of pregnancy and to discuss the perinatal management. Management is complicated and women should be counselled about the maternal and fetal complications, and the pregnancy monitored carefully by a perinatal team with experience in high-risk obstetrics and access to neonatal care. The data reviewed here suggest that a woman who decides to continue with the pregnancy including a CHM must be aware that, overall, she only has a one in four chance of live birth and in around 35% of cases she will develop persistent trophoblastic disease (PTD) after delivery. In ongoing pregnancies, there will be, in at least 20% of the cases, an early onset of pre-eclampsia (PET) and a 29% risk of fetal loss due to late miscarriage, intrauterine death and neonatal death. Maternal serum human chorionic gonadotrophin (MShCG) could be useful in predicting outcome in twin pregnancy combining normal pregnancy and CHM, but this needs to be investigated prospectively. Copyright © 2005 John Wiley & Sons, Ltd.     

Characteristics of drivers not using seat belts in a high belt use state

A study was undertaken in North Carolina to determine the characteristics of the minority of drivers who were not using seat belts following an extensive publicity/enforcement campaign, which had increased statewide use to 80%. Vehicles and drivers whose seat belt use was observed at sites across North Carolina were matched against Division of Motor Vehicles registration and driver history files for vehicle owners. The study file consisted of those observed drivers who matched the owners with respect to sex, race, and approximate age. The results of this investigation indicate that nonuse of seat belts was associated with males; younger age (<35); older vehicles (pre-1985); vehicles other than cars, especially pickups; and poor driving records. Telephone survey information indicated that nonusers were less likely to have health care coverage, more likely to acknowledge having consumed large amounts of alcohol in the past year, and more likely to have an arrest record. When asked about enforcement of the belt use law, many nonusers said that they would not respond to higher fines but they would respond to driver license points. To change the belt use behavior of this hard-core nonuser population, it well may be necessary as was done in Canada to combine publicity/enforcement campaigns with driver license points as a penalty for nonuse.     

Clean fuels from municipal solid waste for fuel cell buses in metropolitan areas

Increasing volumes of municipal solid waste (MSW) pose disposal problems for many cities. Costs are rising as landfilling becomes more difficult. The production of clean transportation fuels (methanol or hydrogen) from MSW is one economically and environmentally promising option for dealing with these problems. An attractive feature is that elimination of essentially all air pollutant emissions is inherent in the process. Current and future air emissions standards should be easily met. Methanol or hydrogen used in fuel cell vehicles (FCV) can help address problems of deteriorating urban air quality due to vehicle pollution and heavy dependence of the transport sector on imported petroleum. Buses are initial targets for commercial application of fuel cells. Coupled with FCVs, MSW could become a major transportation energy resource. For example, less than 25% of New York City's MSW supply would be sufficient to produce the methanol or hydrogen needed to fuel the entire city's bus fleet, if the buses were fuel cell powered. Estimated breakeven tipping fees required for hydrogen or methanol from MSW to compete with the cost of these fuels made from natural gas today are $52 to $89/raw tonne MSW for hydrogen and $64 to $104/raw tonne MSW for methanol (in 1991$), depending on the gasification technology considered. For comparison, the average tipping fee today in New York City is $74/tonne (1991$). Because of the high fuel economies expected for fuel cell buses, total lifecycle costs per bus-km could be lower than for conventional diesel-engine buses.     

HYDROLOGIC LANDSCAPES ON THE DELMARVA PENINSULA PART 1: DRAINAGE BASIN TYPE AND BASE-FLOW CHEMISTRY1

ABSTRACT: The relation between landscape characteristics and water chemistry on the Delmarva Peninsula can be determined through a principal-component analysis of basin characteristics. Two basin types were defined by factor scores: (1) well-drained basins, characterized by combinations of a low percentage of forest cover, a low percentage of poorly drained soil, and elevated channel slope; and (2) poorly drained basins, characterized by a combinations of an elevated percentage of forest cover, an elevated percentage of poorly drained soil, and low channel slopes. Results from base-flow sampling of 29 basins during spring 1991 indicate that water chemistry of the two basin types differ significantly. Concentrations of calcium, magnesium, potassium, alkalinity, chloride, and nitrate are elevated in well-drained basins, and specific conductance is elevated. Concentrations of aluminum, dissolved organic carbon, sodium, and silica are elevated in poorly drained basins whereas specific conductance is low. The chemical patterns found in well-drained basins can be attributed to the application of agricultural chemicals, and those in poorly drained basins can be attributed to ground-water flowpaths. These results indicate that basin types determined by a quantitative analysis of basin characteristics can be related statistically to differences in base-flow chemistry, and that the observed statistical differences can be related to major processes that affect water chemistry.     

VARIABLES INDICATING NITRATE CONTAMINATION IN BEDROCK AQUIFERS,NEWARK BASIN,NEW JERSEY1

ABSTRACT: Variables that describe well construction, hydrogeology, and land use were evaluated for use as possible indicators of the susceptibility of ground water in bedrock aquifers in the Newark Basin, New Jersey, to contamination by nitrate from the land surface. Statistical analyses were performed on data for 132 wells located throughout the Newark Basin. Concentrations of nitrate (as nitrogen) did not exceed the U.S. Environmental Protection Agency maximum contaminant level of 10 milligrams per liter (mg/L) in any of the water samples (U.S. Environmental Protection Agency, 1991). Variables that describe hydrogeology and well construction were found not to be statistically significant in relation to concentrations of nitrate. This finding can be attributed to the complex nature of flow in bedrock aquifers and mixing of water from shallow and deep water-bearing zones that occurs within these wells, which are constructed with long open intervals. Distributions of nitrate concentrations were significantly different among land-use groups on the basis of land use within both a 400 and an 800-m radius zone of the well. The median concentrations of nitrate (as N) in water from wells in predominantly urban-residential (2.5 mg/L) and agricultural areas (1.8 mg/L) were greater than the median concentration of nitrate in water from wells in predominantly undeveloped areas (0.5 mg/L).     

Influence of groundwater conditions and co‐contaminants on sorption of perfluoroalkyl compounds on granular activated carbon

Per and polyfluoroalkyl substances (PFAS) are emerging and persistent organic pollutants that have been detected in many environmental media, humans, and wildlife. A common method to effectively remove PFAS from water is adsorption by activated carbon. Preliminary sorption experiments were conducted using five characterized Calgon Corporation coal‐based granular activated carbon (GAC; F100, F200, F816, F300, and F400), one coconut‐based GAC (CBC‐OLC 12 × 30), and one Jacobi Corporation coal‐based GAC (Omni‐G 12 × 40). Sorption of four representative PFAS onto each GAC was measured to select the most favorable carbon sources. F400 and CBC were chosen based on their performance in preliminary PFAS sorption experiments and contrasting properties. Freundlich and Langmuir isotherm models were developed for perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonate (PFOS) at an initial concentration of 1 mg/L. Sorption capacities were determined for PFOA and PFOS individually and in the mixture. Individual compounds showed higher sorption than when present in the mixture for both PFOA and PFOS. PFOS showed higher sorption than PFOA both individually and in the mixture and F400 showed higher sorption capacity than CBC. The presence of co‐contaminants (kerosene, trichloroethylene, and ethanol), and variations in groundwater conditions (pH, presence of anions, naturally occurring organic matter, and iron oxides) demonstrated limited impact on the sorption of PFAS onto GAC under the experimental conditions tested.     

Sediment Availability and Erosion Rates on Off‐Highway Vehicle Trails in the Ouachita Mountains,USA

Factors influencing sediment availability are assessed and erosion rates are quantified for an off‐highway vehicle (OHV) trail system in the Ouachita Mountains of Arkansas. As of May 2012, the Wolf Pen Gap trail system included 77.0 km of "trails" which consist of county roads; open and closed Forest Service roads; and open and closed OHV trails. For a given trail length, the sediment volume available to be eroded is determined by bare trail width and sediment depth. Four condition types are defined that group trail sections based on statistically different trail widths or depths. Trail construction method appears to influence sediment availability differences more than erosion potential (as indexed by trail slope gradient and length). The range for annual trail erosion rates is estimated as 75 and 210 tonne/ha/yr. The high and low rates are obtained using two independent methods. The 210 tonne/ha/yr rate is computed from mean sediment capture at 30 sediment traps installed for 0.5–1.0 year. The 75 tonne/ha/yr rate is computed assuming all available trail sediment measured in a one‐time sampling is eroded over the next year. We argue in support of this assumption and suggest both rate values may be conservative. Trail erosion rates and sediment trap observations indicate frequent trap cleanout will be needed to continue sediment capture from All Terrain Vehicle trails.     

Economic appraisal and evaluation of UK waste minimisation clubs: proposals to inform the design of sustainable clubs

Waste minimisation clubs have been established for some 12 years in the UK. During that time, they have been significant driving forces in disseminating sustainable waste management practices in industry and commerce. Clubs have also demonstrated that they can achieve significant reductions in levels of waste. However, data on the economic benefits of these clubs remain scanty and disparate. In addition, no standard methodology has developed to assess whether the investment costs of clubs can be justified on grounds of either economic welfare or sustainable development, despite the theoretical advantages from doing so. Against this background, the paper considers the need for economic appraisal and evaluation of waste minimisation clubs and discusses how these methods could be applied to the creation of clubs that will be sustainable over time.     

Impact of sample preparation on mineralogical analysis of zero-valent iron reactive barrier materials

Permeable reactive barriers (PRBs) of zero-valent iron (Fe(0)) are increasingly being used to remediate contaminated ground water. Corrosion of Fe(0) filings and the formation of precipitates can occur when the PRB material comes in contact with ground water and may reduce the lifespan and effectiveness of the barrier. At present, there are no routine procedures for preparing and analyzing the mineral precipitates from Fe(0) PRB material. These procedures are needed because mineralogical composition of corrosion products used to interpret the barrier processes can change with iron oxidation and sample preparation. The objectives of this study were (i) to investigate a method of preparing Fe(0) reactive barrier material for mineralogical analysis by X-ray diffraction (XRD), and (ii) to identify Fe mineral phases and rates of transformations induced by different mineralogical preparation techniques. Materials from an in situ Fe(0) PRB were collected by undisturbed coring and processed for XRD analysis after different times since sampling for three size fractions and by various drying treatments. We found that whole-sample preparation for analysis was necessary because mineral precipitates occurred within the PRB material in different size fractions of the samples. Green rusts quickly disappeared from acetone-dried samples and were not present in air-dried and oven-dried samples. Maghemite/magnetite content increased over time and in oven-dried samples, especially after heating to 105 degrees C. We conclude that care must be taken during sample preparation of Fe(0) PRB material, especially for detection of green rusts, to ensure accurate identification of minerals present within the barrier system.