Current concepts of Down syndrome screening tests in assisted reproduction twin pregnancies: another double trouble

Assisted reproductive technologies (ART) have increased both the number of pregnancies in women beyond the age of 35 and the incidence of multiple pregnancies. Various methods of screening for Down syndrome (DS) were introduced in clinical practice during the last two decades, and specific problems were encountered when they were applied for twin pregnancies. The current review aims to explore the problematic issue of prenatal DS screening in ART twins. Overall, more women with twin pregnancies (mainly those who conceived via assisted reproduction) are found to be false positive for DS. This is because mid-trimester maternal serum screening is associated with a higher false-positive rate secondary to changes in the feto-placental endocrinologic metabolism, reflected mainly in high human chorionic gonadotrophin (hCG) levels in the ART pregnancies. First-trimester nuchal translucency (NT) measurement in twin pregnancies is not affected by the problems encountered in serum screening. This sonographic screening approach enables a fetus-specific identification of those fetuses at high risk of DS and is associated with a lower false-positive rate than mid-trimester serum screening. DS screening in ART twins presents several challenges in determining the most appropriate screening test modality. Whether there is any significant benefit of adding first-trimester biochemistry or nasal bone scanning in screening ART-conceived twins awaits further investigation. Copyright © 2005 John Wiley & Sons, Ltd.     

Environmental policy indicators: A systems model

This article describes and tests a systems theory-based policy indicators model. The framework is used to examine propositions about linkages between states' ecological-spatial characteristics and subsequent selected solid waste management (SWM) -related environmental policies. It was hypothesized that state characteristics of: (1) population density (used as a garbage-per-land area index), (2) population convergence within urban areas, and (3) percent population change in the interval 1980–1985, could jointly explain state variation in both the number and the vigor of SWM policy outputs. Greater levels of spatial pressure were proposed to be related directly to more numerous, more convincing policies. Proposals are grounded in the literature of organizational search theory, crisis stimulation, and technological pressure. Results revealed that the sociospatial model in fact could explain a reasonable proportion of policy variation across states. However, not all hypotheses are supported. Population change shows an indirect, rather than the anticipated direct, relationship with policy output levels. In addition, when used in the model as a pollution intensity index, population density failed to contribute significantly to an explanation of differences in state SWM policy levels. The analysis raises questions about changes occurring over time in the nature and direction of linkages between sociospatial measures and policy responses. This study suggests that strengthening policy indicator models may require questioning key assumptions and theoretical bases, conducting longitudinal studies, and factoring in political, economic, and other policy environment forces.     

LEVEL B WATER RESOURCES PLANNING IN AN URBAN SETTING1

The purpose of this paper is to describe how the Level B Water Resources Planning Process was applied to Long Island Sound and the land area around it, to summarize the major findings and recommendations of the study and to comment on the effectiveness of that process and suggest how it might be made more effective in the future.     

Cascading ecological effects of low-level phosphorus enrichment in the Florida everglades

Few studies have examined long-term ecological effects of sustained low-level nutrient enhancement on wetland biota. To determine sustained effects of phosphorus (P) addition on Everglades marshes we added P at low levels (5, 15, and 30 microg L(-1) above ambient) for 5 yr to triplicate 100-m flow-through channels in pristine marsh. A cascade of ecological responses occurred in similar sequence among treatments. Although the rate of change increased with dosing level, treatments converged to similar enriched endpoints, characterized most notably by a doubling of plant biomass and elimination of native, calcareous periphyton mats. The full sequence of biological changes occurred without an increase in water total P concentration, which remained near ambient levels until Year 5. This study indicates that Everglades marshes have a near-zero assimilative capacity for P without a state change, that ecosystem responses to enrichment accumulate over time, and that downstream P transport mainly occurs through biota rather than the water column.     

Laboratory-scale measurement of trace gas fluxes from landfarm soils

Trace gas emissions from refinery and bioremediation landfarms were investigated in a mesocosm-scale simulator facility. Five simulators were constructed and integrated with a data acquisition system and trace gas analyzers, allowing automated real-time sampling and calculation of total hydrocarbon (THC), CO2, and water vapor fluxes. Experiments evaluating the influence of simulated cultivation and rainfall on trace gas fluxes from the soil surfaces were conducted. Results were compared with published field results. Results showed that cultivating dry or moderately wet soil resulted in brief enhancements of THC fluxes, up to a factor of 10, followed by a sharp decline. Cultivating dry soil did not enhance respiration. Cultivating wet soil did result in sustained elevated levels of respiration. Total hydrocarbon emissions were also briefly enhanced in wet soils, but to a lesser magnitude than in dry soil. Hydrocarbon fluxes from refinery landfarm soil were very low for the duration of the experiments. This lead to the conclusion that elevated THC fluxes would only be expected during waste application. An evaluation of the influence of simultaneous water vapor fluxes on other trace gas fluxes highlighted the importance in lab-scale experiments of correcting trace gas fluxes from soils. The results from this research can be used to guide management practices at landfarms and to provide data to aid in assessing the effect of landfarms.     

SITE Program Success: Cost Savings to Government and Increased Revenue for Technology Vendors

The Superfund Innovative Technology Evaluation (SITE) program is a program mandated by Congress through the 1986 Superfund Amendments and Reauthorization Act (SARA). The original Superfund allowed no provisions for research and development of needed remediation technologies. Problems arose when the demand for involved, complex treatment could not be met by the traditional contain, haul, and dispose process that hazardous waste handlers had become familiar with. In response to the increasing complexity of hazardous waste site remediation, SARA called for an “Alternative or Innovative Treatment Technology Research and Demonstration Program.” As a result, EPA's Office of Solid Waste and Emergency Response and the Office of Research and Development established the SITE program. This article is a historical analysis of the unique cost savings of the SITE program.     

Changing corporate environmental philosophy: Project renewal gets companies started

Project RENEWAL is an innovative new environmental business project taking place in New Jersey. Project RENEWAL stands for Resource Efficiency Network to Eliminate Waste and Liability. The purpose of this project is to investigate and promote the linkages between ecology, technology, and business economics for the benefit of the economy and the environment. This is a collaborative effort, initially focused on equipment and inventory assets, between the business and environmental communities in order to explore new ways to increase business efficiency and profitability and also benefit the environment. Participants in the project include representatives from industry, consulting, local and state government, environmental agencies, trade groups and academia. This article will outline the background and initial framework of Project RENEWAL's initiatives. (The authors are open to comments, suggestions, criticism, and most importantly input from others who share their vision and are willing to cooperatively accelerate the change process).