Prenatal diagnosis of mosaicism for triploidy and trisomy 13

Mosaicism for trisomy 13 and triploidy was detected by amniocentesis performed at 18 weeks' gestation because of fetal anomalies. Pregnancy continued and a live-born male was delivered vaginally at 37 weeks. The infant had features common to both trisomy 13 and triploidy: intrauterine growth retardation (IUGR), small abnormal ears, cleft palate, and a small jaw. In addition, he had complete cutaneous syndactyly of fingers 3 and 4 and partial syndactyly of the toes, as seen in triploidy. Mixoploidy for trisomy 13 and triploidy was confirmed postnatally in blood, skin, and placenta. Examination of chromosome heteromorphisms and DNA markers suggested the presence of two maternal contributions in the triploid cell line. In addition, the extra chromosome 13 in the trisomic cell line was derived from the mother. Copyright © 2001 John Wiley & Sons, Ltd.     

Sulphate, Nitrogen and Base Cation Budgets at 21 Forested Catchments in Canada, the United States and Europe

To assess the concern over declining base cation levels in forest soils caused by acid deposition, input-output budgets (1990s average) for sulphate (SO₄), inorganic nitrogen (NO₃-N; NH₄-N), calcium (Ca), magnesium (Mg) and potassium (K) were synthesised for 21 forested catchments from 17 regions in Canada, the United States and Europe. Trend analysis was conducted on monthly ion concentrations in deposition and runoff when more than 9 years of data were available (14 regions, 17 sites). Annual average SO₄ deposition during the 1990s ranged between 7.3 and 28.4 kg ha⁻¹ per year, and inorganic nitrogen (N) deposition was between 2.8 and 13.8 kg ha⁻¹ per year, of which 41–67% was nitrate (NO₃-N). Over the period of record, SO₄ concentration in deposition decreased in 13/14 (13 out of 14 total) regions and SO₄ in runoff decreased at 14/17 catchments. In contrast, NO₃-N concentrations in deposition decreased in only 1/14 regions, while NH₄-N concentration patterns varied; increasing at 3/14 regions and decreasing at 2/14 regions. Nitrate concentrations in runoff decreased at 4/17 catchments and increased at only 1 site, whereas runoff levels of NH₄-N increased at 5/17 catchments. Decreasing trends in deposition were also recorded for Ca, Mg, and K at many of the catchments and on an equivalent basis, accounted for up to 131% (median 22%) of the decrease in acid anion deposition. Base cation concentrations in streams generally declined over time, with significant decreases in Ca, Mg and K occurring at 8, 9 and 7 of 17 sites respectively, which accounted for up to 133% (median 48%) of the decrease in acid anion concentration. Sulphate export exceeded input at 18/21 catchments, likely due to dry deposition and/or internal sources. The majority of N in deposition (31–100%; median 94%) was retained in the catchments, although there was a tendency for greater NO₃-N leaching at sites receiving higher (<7 kg ha^-1 per year) bulk inorganic N deposition. Mass balance calculations show that export of Ca and Mg in runoff exceeds input at all 21 catchments, but K export only exceeds input at 16/21 sites. Estimates of base cation weathering were available for 18 sites. When included in the mass balance calculation, Ca, Mg and K exports exceeded inputs at 14, 10 and 2 sites respectively. Annual Ca and Mg losses represent appreciable proportions of the current exchangeable soil Ca and Mg pools, although losses at some of the sites likely occur from weathering reactions beneath the rooting zone and there is considerable uncertainty associated with mineral weathering estimates. Critical loads for sulphur (S) and N, using a critical base cation to aluminium ratio of 10 in soil solution, are currently exceeded at 7 of the 18 sites with base cation weathering estimates. Despite reductions in SO₄ and H⁺ deposition, mass balance estimates indicate that acid deposition continues to acidify soils in many regions with losses of Ca and Mg of primary concern. The U.S. Government's right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. The Canadian Crown reserves the right to retain a non-exclusive, royalty free licence in and to any copyright.     

Declines in organochlorines in eggs of red-breasted mergansers from Lake Michigan, 1977–1978 versus 1990

From 1977–1978 to 1990, concentrations of polychlorinated biphenyls (PCBs) and most organochlorine pesticides declined in eggs of red-breasted mergansers (Mergus serrator) nesting on islands in northwestern Lake Michigan. Total PCBs decreased 60% (from 21 ppm in 1977–1978 to 8.5 ppm in 1990) and p,p-DDE decreased 66% (from 6.5 to 2.2 ppm). Dieldrin decreased only 16% (from 0.82 to 0.69 ppm). In 1990, 79.1% of incubated eggs hatched, which was not significantly different from the 83.5% that hatched in 1977–1978.The U.S. Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.     

A simple economic model of endangered species preservation in the United States

Concern for the acceleration in threats to species diversity in the United States led to the passage of the Endangered Species Act of 1973. In this paper, this legislation is examined in an economic context. A simple model is developed where management and constraints on economic activity are substitutes in the production of species stocks. Whether economic growth constraints (the primary policy tool of the 1973 Act) are justified for preservation purposes depends on technical substitution possibilities, relative cost ratios, and the existence of budget constraints for species management. Since the same combination of these factors will not occur for all species, it is argued that more flexibility in endangered species policy may preserve the same levels of species stocks at lower costs to society.     

Reducing car-based journeys to work: What potential is there and whose responsibility is it?

To date the transport solutions seeking to reduce traffic impacts have tended to focus on city/town centres. There has, however, been a substantial increase in traffic levels both in and to suburban areas and the location of large employment sites in such areas has had a significant impact. The typical policy response to traffic in these areas has been the introduction of traffic calming measures and residents' parking but such policies do not address the fundamental issue of travel generation and its consequences (including parking). Major employers should have an important role to play in the consideration of more sensible and sustainable uses of the car including the promotion of alternatives to car use. Using a case study at a large institution in Oxford this paper examines findings from a survey into staff travel behaviour in order to identify how staff currently behave. It explores the potential for transport and non-transport solutions to reduce car-based journeys to work and concludes that there is real potential to encourage a reduction in car-based travel. The paper seeks to widen the debate about who should take responsibility for achieving such a reduction. It argues that whilst travel awareness campaigns primarily push responsibility onto individuals an 'integrated package' is required with employers also assuming responsibility and thereby enabling individuals to adapt.     

Pesticide Impact Rating Index – A Pesticide Risk Indicator for Water Quality

Pesticide users, natural resource managers, regulators, government agencies and many others are concerned about the off-site impact of pesticides on the environment. Systematic methods of the assessment of potential risk of pesticides to environmental components can serve as valuable tools in decision making and policy formulation. Simple risk indicators have been developed which cover a range of scenarios such as toxicity to organisms, health of farm workers, consumer health, and residues in harvested produce. The authors have developed a software package named Pesticide Impact Rating Index (PIRI) that outputs an improved pesticide risk indicator for water quality. PIRI is a standalone, user-friendly, platform-independent program. It can be used to (i) rank pesticides in terms of their relative pollution potential to groundwater or surface water, and (ii) to compare different land uses in a catchment or at a regional scale in terms of their relative impact on water quality. It is based on pesticides use; the pathway through which the pesticides are released to the water resources (drift, runoff, erosion, leaching) and the value of the water resources threatened. Each component is quantified using pesticide characteristics (including toxicity to organisms at different trophic levels, i.e. fish, daphnia, algae, etc.), environmental and site conditions (e.g. organic carbon content of soil, water input, slope of land, soil loss, recharge rate, depth of water table, etc.). This paper describes two case studies of the application of PIRI in Australia. The comparison of the risk assessment by PIRI on these revealed that PIRI correctly estimated the pollution potential of pesticides in greater than 80% of cases. A GIS version of PIRI is described in a companion paper in this volume. An erratum to this article is available at .     

Cattle feedlot soil moisture and manure content: I. Impacts on greenhouse gases, odor compounds, nitrogen losses, and dust

Beef cattle feedlots face serious environmental challenges associated with manure management, including greenhouse gas, odor, NH3, and dust emissions. Conditions affecting emissions are poorly characterized, but likely relate to the variability of feedlot surface moisture and manure contents, which affect microbial processes. Odor compounds, greenhouse gases, nitrogen losses, and dust potential were monitored at six moisture contents (0.11, 0.25, 0.43, 0.67, 1.00, and 1.50 g H2O g(-1) dry matter [DM]) in three artificial feedlot soil mixtures containing 50, 250, and 750 g manure kg(-1) total (manure + soil) DM over a two-week period. Moisture addition produced three microbial metabolisms: inactive, aerobic, and fermentative at low, moderate, and high moisture, respectively. Manure content acted to modulate the effect of moisture and enhanced some microbial processes. Greenhouse gas (CO2, N2O, and CH4) emissions were dynamic at moderate to high moisture. Malodorous volatile fatty acid (VFA) compounds did not accumulate in any treatments, but their persistence and volatility varied depending on pH and aerobic metabolism. Starch was the dominant substrate fueling both aerobic and fermentative metabolism. Nitrogen losses were observed in all metabolically active treatments; however, there was evidence for limited microbial nitrogen uptake. Finally, potential dust production was observed below defined moisture thresholds, which were related to manure content of the soil. Managing feedlot surface moisture within a narrow moisture range (0.2-0.4 g H2O g(-1) DM) and minimizing the accumulation of manure produced the optimum conditions that minimized the environmental impact from cattle feedlot production.