Separation of selected PAHs by using high performance capillary electrophoresis with modifiers

The effect of varying SDS concentration in a micellar electrokinetic capillary chromatographic system (MECC) is investigated. In addition, the introduction of -cyclodextrin as modifier to the electrophoretic medium, containing SDS and a phosphate-borate buffer, is shown to give satisfactory separation of the seven selected PAHs. The separation efficiency is increased with the addition of -cyclodextrin.     

Sulfate and conductivity as field indicators for detecting coal-mining pollution

A water quality assessment was conducted on three Appalachian streams polluted by coal mining at the Big South Fork National River and Recreation Area, Tennessee and Kentucky. Results showed that sulfate was an excellent parameter for detecting the effects of coal mining and that sulfate analyses used in conjunction with conductivity readings provided the best detection index. Acidity and pH readings were relatively insensitive indicators, reflecting the mining pollution only after sulfate concentrations already indicated severe pollution levels.Hydrologist, Big South Fork NRRA, during the study; presently at Cape Lookout National SeashoreHydrologist, NPS, during the study; presently with USDA-Forest Service, Washington, DC.     

Prenatal diagnosis of the fragile X using thymidine induction

Eleven pregnancies in ten patients at risk for the fragile X were monitored by amniocentesis or chorion villus biopsy and induction of the fragile site using thymidine, methotrexate and FUdR. Three female fetuses and one male fetus were found to have the fragile X. The results obtained using thymidine induction were superior to those using methotrexate induction and probably better than those obtained using FUdR induction.     

Hamburgers and the Rainforest – a Review of Issues and Evidence

This paper examines the relationship between North American beef consumption and deforestation in South and Central America. Some writers have argued that consumption of hamburgers in North America, particularly hamburgers consumed in fast food restaurants, contributes to the depletion of the rainforest in South and Central America. We survey the published policy literature on the causes of rainforest depletion in the region. We also review the published estimates of the rate and extent of clearing of rainforest that has occurred in South and Central America since 1970. Finally, we review the data on beef imports and consumption in Canada and the United States in a effort to assess the importance of South and Central America as suppliers of beef to the North American market. We conclude that the relationship between beef consumption in North America should not be considered an important cause of forest depletion in South and Central America. Domestic policies and market forces in the countries where rainforests are located are the leading causes of rainforest depletion in this region. This lesson seems to have been lost on some popular and even some textbook writers on this subject. This revised version was published online in August 2006 with corrections to the Cover Date.     

Exploring the risks and benefits of flexibility in biodiversity offset location in a case study of migratory shorebirds

Biodiversity offsets aim to counterbalance the residual impacts of development on species and ecosystems. Guidance documents explicitly recommend that biodiversity offset actions be located close to the location of impact because of higher potential for similar ecological conditions, but allowing greater spatial flexibility has been proposed. We examined the circumstances under which offsets distant from the impact location could be more likely to achieve no net loss or provide better ecological outcomes than offsets close to the impact area. We applied a graphical model for migratory shorebirds in the East Asian–Australasian Flyway as a case study to explore the problems that arise when incorporating spatial flexibility into offset planning. Spatially flexible offsets may alleviate impacts more effectively than local offsets; however, the risks involved can be substantial. For our case study, there were inadequate data to make robust conclusions about the effectiveness and equivalence of distant habitat-based offsets for migratory shorebirds. Decisions around offset placement should be driven by the potential to achieve equivalent ecological outcomes; however, when considering more distant offsets, there is a need to evaluate the likely increased risks alongside the potential benefits. Although spatially flexible offsets have the potential to provide more cost-effective biodiversity outcomes and more cobenefits, our case study showed the difficulty of demonstrating these benefits in practice and the potential risks that need to be considered to ensure effective offset placement.     

Malondialdehyde concentrations in the intestine and gills of Vardar chub (Squalius vardarensis Karaman) as indicator of lipid peroxidation

Environmental Science and Pollution Research - A lipid peroxidation product, malondialdehyde (MDA), was studied in Vardar chub (Squalius vardarensis Karaman) as an indicator of oxidative stress,...     

Quantifying population declines based on presence‐only records for red‐list assessments

Accurate trend estimates are necessary for understanding which species are declining and which are most in need of conservation action. Imperfect species detection may result in unreliable trend estimates because this may lead to the overestimation of declines. Because many management decisions are based on population trend estimates, such biases could have severe consequences for conservation policy. We used an occupancy‐modeling framework to estimate detectability and calculate nationwide population trends for 14 Swiss amphibian species both accounting for and ignoring imperfect detection. Through the application of International Union for Conservation of Nature Red List criteria to the different trend estimates, we assessed whether ignoring imperfect detection could affect conservation policy. Imperfect detection occurred for all species and detection varied substantially among species, which led to the overestimation of population declines when detectability was ignored. Consequently, accounting for imperfect detection lowered the red‐list risk category for 5 of the 14 species assessed. We demonstrate that failing to consider species detectability can have serious consequences for species management and that occupancy modeling provides a flexible framework to account for observation bias and improve assessments of conservation status. A problem inherent to most historical records is that they contain presence‐only data from which only relative declines can be estimated. A move toward the routine recording of nonobservation and absence data is essential if conservation practitioners are to move beyond this toward accurate population trend estimation.     

The response of a mid- and high latitude peat bog to predicted climate change: methane production in a 12-month peat incubation

There are fears that global warming will lead to degradation of peatlands, higher emissions of greenhouse gases from peat, and accelerated warming. Anaerobic decomposition of organic soils produces methane (CH₄), a potent greenhouse gas. Two peat bogs differing in mean annual temperature, Velke Darko (VD, Czech Republic, 7.2 °C), and Stor Åmyran (SA, Sweden, 4.0 °C), were selected for a comparative study of how organic soils in different climatic zones will respond to warmer and drier conditions. Twenty peat cores from each bog were incubated in growth chambers. Under present-day summer conditions, VD produced 14 times more CH₄ than SA. Two different warming scenarios were used. Peat-core replicates were kept at temperatures of 11 versus 16 °C, and 11 versus 22 °C. From 11 to 16 °C, the CH₄ production slightly decreased at SA, and slightly increased at VD. From 11 to 22 °C, the CH₄ production increased 9 times at SA, but slightly decreased at VD. After an 8-month incubation, peat cores under drying conditions (water table at ?14 cm) were compared to samples with original water table (?2 cm). Drying conditions led to a steeper reduction in CH₄ production at VD, compared to SA. The CH₄ production decreased more than 100 times at VD. Then, the combined effect of simultaneous warming and drying at 11 and 22 °C was studied. We did not find any significant effect of interactions between increasing temperature and decreasing water table level. Overall, the warmer site VD responded more strongly to the simulated climate change than the colder site SA.