Prenatal diagnosis of mosaic tetrasomy 5p

We report the prenatal diagnosis of a fetus with tetrasomy 5p mosaicism resulting from a supernumerary isochromosome for the short arm of chromosome 5. The pregnancy was terminated and fetal autopsy revealed minor facial abnormalities (long philtrum, up-slanting palpebral fissures and a broad nasal bridge). Cultures were established from fetal skin, kidney, and pancreas for cytogenetic analysis; the i(5p) was observed only in the skin fibroblasts. To our knowledge, this is the fourth report of mosaic tetrasomy 5p and the first report of prenatal diagnosis of this abnormality. Copyright © 2001 John Wiley & Sons, Ltd.     

The cost of tolerance: sensitivity of stream benthic communities to UV-B and metals.

The ability to tolerate disturbance is a defense strategy that minimizes the effects of damage to fitness and is essential for sustainability of populations, communities, and ecosystems. Despite the apparent benefits of tolerance, there may be an associated cost that results in a deficiency of a system to respond to additional disturbances. Aquatic ecosystems are often exposed to a variety of natural and anthropogenic disturbances, and the effects of these compound perturbations are not well known. In this investigation, we examine whether tolerance to one stressor, metals, results in a cost of increased sensitivity to an additional stressor, ultraviolet-B (UV-B) radiation. Heavy metal pollution is recognized as a major environmental problem in Rocky Mountain streams. These high-elevation, typically clear streams may be at particular risk to elevated UV-B levels associated with reduced levels of ozone. Microcosm experiments were conducted using natural stream benthic communities collected from a reference site and a site with a long-term history of heavy-metal pollution. Direct and interactive effects of heavy metals and UV-B radiation on structural and functional characteristics of benthic communities were evaluated among four treatments: control, UV-B, metals, and metal and UV-B. Communities from the metal-polluted site were more tolerant of metals but less tolerant to UV-B compared to reference communities. Increased mayfly drift and reduced metabolism in response to metal exposure were observed in reference communities but not in the metal-polluted communities. In contrast to these results, UV-B radiation significantly reduced community metabolism, total macroinvertebrate abundance, and abundances of mayflies, caddisflies, and dipterans from the metal-polluted site, but had no effects on benthic communities from the reference site. ANOSIM results demonstrated that community responses differed among treatments at both sites. Metals had the largest impact on community differences at both sites, while UV-B had greater impacts at the metal-polluted site. This research demonstrates the need to account for potential costs associated with tolerance and that these costs can result in behavioral, structural, and functional impacts to benthic communities.     

Development and Applications of Microbial Ecogenomic Indicators for Monitoring Water Quality: Report of a Workshop Assessing the State of the Science, Research Needs and Future Directions

This article brings forth recommendations from a workshop sponsored by the U.S. Environmental Protection Agency's Science to Achieve Results (STAR) and Environmental Monitoring and Assessment (EMAP) Programs and by the Council of State Governments, held during May 2002 in Kansas City, Kansas. The workshop assembled microbial ecologists and environmental scientists to determine what research and science is needed to bring existing molecular biological approaches and newer technologies arising from microbial genomic research into environmental monitoring and water quality assessments. Development of genomics and proteomics technologies for environmental science is a very new area having potential to improve environmental water quality assessments. The workshop participants noted that microbial ecologists are already using molecular biological methods well suited for monitoring and water quality assessments and anticipate that genomics-enabled technologies could be made available for monitoring within a decade. Recommendations arising from the workshop include needs for (i) identification of informative microbial gene sequences, (ii) improved understandings of linkages between indicator taxa, gene expression and environmental condition, (iii) technological advancements towards field application, and (iv) development of the appropriate databases. Contribution no. 1217 from the NHEERL Gulf Ecology Division. All authors contributed equally to this publication.     

Biochemical and biological assays of endocrine disrupting compounds in various manure matrices

Wastes generated by animal agriculture have complex matrices and present a significant challenge for achieving accurate measurements of estrogens. The objective of this study was to compare two different extraction methods and two different biochemical and biological estrogen assays on two dairy manure matrices. The two extraction methods studied in this research were a two-step base-toluene extraction and a one-step cyclohexane extraction. The two assays assessed were an enzyme-linked immunosorbent assay (ELISA) and a yeast estrogen screen (YES) bioassay. Estrogenic activity was measured directly as 17beta-estradiol (E2) through the ELISA method or as E2 equivalents (E2-eq) through the YES bioassay. Both extraction methods yielded reasonable recoveries from distilled water in the absence of matrix interferences. In manure samples, ELISA resulted in recoveries slightly higher than 100% in two types of dairy manures, but YES recoveries varied. The YES bioassay detected much higher estrogenic activities in dairy manure compared to the E2 concentrations measured by ELISA. The base-solvent extraction yielded higher E2 concentrations in dairy manure compared to the one-step cyclohexane extraction. These results suggest that manure matrices vary sufficiently that extraction methods must be optimized for specific assays utilized to quantify estrogens in manures.     

Land poverty and emerging ruralities in Cambodia: insights from Kampot province

Rural change in Cambodia manifests itself in rapidly declining land availability for the smallholder sector, posing the question of how farmers may be able to deal with limited access to land. In this paper, we discuss with a case study village and household livelihood strategies of smallholders currently operating under land-constrained conditions. Based on an integrated assessment of a smallholder village in Kampot province, we illustrate in quantitative terms how land shortage is creating problems of surplus generation and liquidity issues in monetary and non-monetary flows. At the household level, livelihood diversification based on the involvement of productive resources other than land may play an increasing role, particularly in the future, when levels of land shortage may increase. At the village level, smallholder may respond through institutional innovation, in particular through the establishment of a community banking system and a paddy rice bank to provide money and rice credits to overcome transitory shortages and to cover investment costs for additional productive resources. Thus, in this case, we observe the emergence of new patterns of livelihood in rural areas, based on the integration of non-land-based economic activities and new institutional settings.     

Patterns of shell repair in articulate brachiopods indicate size constitutes a refuge from predation

The cost of overcoming prey defenses relative to the value of internal tissues is a key criterion in predator/prey interactions. Optimal foraging theory predicts: (1) specific sizes of prey will result in the best returns to predators, and (2) there will often be a size at which the cost/benefit balance is low enough to effectively exclude predation. Data presented here on styles of repaired shell damage and size at which injury had been sustained was collected from samples of terebratulide brachiopods from the Antarctic Peninisula (Liothyrella uva), Falkland Islands (Magellania venosa and Terebratella dorsata) and Chile (M. venosa). The predominant form of damage on shells was indicative of predators attacking the valve margins. The modal size for repaired damage was more than 10 mm smaller than the modal size for the overall size distribution in each species and there were no repaired attacks in the largest size classes of any species. These data suggest that size forms a refuge from predation, as would be predicted by optimal foraging theory. The optimal sizes that predators appeared to attack vary between species, as do the sizes that provided a refuge from predation. High levels of multiple repairs (19% of the M. venosa population from the Falkland Islands sampled had 2 or more repairs) suggest that the mortality following attack is low, suggesting that many predators abandon their attacks.     

Effect of chimneys on indoor air concentrations of PM10 and benzo[a]pyrene in Xuan Wei,China

This paper reports the effect of chimneys in reducing indoor air pollution in a lung cancer epidemic area of rural China. Household indoor air pollution concentrations were measured during unvented burning (chimneys blocked) and vented burning (chimneys open) of bituminous coal in Xuan Wei, China. Concentrations of particulate matter with an aerodynamic diameter of 10 μm or less (PM₁₀) and of benzo[a]pyrene (BaP) were measured in 43 homes during normal activities. The use of chimneys led to significant decreases in indoor air concentrations of particulate matter with an aerodynamic diameter of 10 μm or less (PM₁₀) by 66% and of benzo[a]pyrene (BaP) by 84%. The average BaP content of PM₁₀ also decreased by 55% with the installation of a chimney. The reduction of indoor pollution levels by the installation of a chimney supports the epidemiology findings on the health benefits of stove improvement. However, even in the presence of a chimney, the indoor air concentrations for both PM₁₀ and BaP still exceeded the indoor air quality standards of China. Movement up the energy ladder to cleaner liquid or gaseous fuels is probably the only sustainable indoor air pollution control measure.     

Fuel Reduction Management Practices in Riparian Areas of the Western USA

Two decades of uncharacteristically severe wildfires have caused government and private land managers to actively reduce hazardous fuels to lessen wildfire severity in western forests, including riparian areas. Because riparian fuel treatments are a fairly new management strategy, we set out to document their frequency and extent on federal lands in the western U.S. Seventy-four USDA Forest Service Fire Management Officers (FMOs) in 11 states were interviewed to collect information on the number and characteristics of riparian fuel reduction treatments in their management district. Just under half of the FMOs surveyed (43%) indicated that they were conducting fuel reduction treatments in riparian areas. The primary management objective listed for these projects was either fuel reduction (81%) or ecological restoration and habitat improvement (41%), though multiple management goals were common (56%). Most projects were of small extent (93% < 300 acres), occurred in the wildland-urban interface (75%), and were conducted in ways to minimize negative impacts on species and habitats. The results of this survey suggest that managers are proceeding cautiously with treatments. To facilitate project planning and implementation, managers recommended early coordination with resource specialists, such as hydrologists and fish and wildlife biologists. Well-designed monitoring of the consequences of riparian fuel treatments on fuel loads, fire risk, and ecological effects is needed to provide a scientifically-defensible basis for the continued and growing implementation of these treatments.     

Specific and long-term effects of Nova Scotia's graduated licensing program

A graduated licensing (GL) program was introduced in Nova Scotia, Canada, in October 1994. Previous research has shown that it reduced collisions in the short term. The present study examined the relative contribution of each stage of the program (i.e., learner and intermediate levels) and the program's impact after beginning drivers graduated to full licensure. The research focused on teenage beginning drivers (age 16-17), but the effects on older beginners also was examined. Per-driver crash rates of two groups of novices selected from driver records in Nova Scotia were compared. One group (pre-GL) received their learner's permits during the 2 years before the program was implemented, and the second group (GL) received their learner's permits during the 2 years after implementation. The findings clearly establish that most of the collision reduction in Nova Scotia's program occurred during the first year of the program, particularly during the first 6 months when the majority of novices were driving under supervision. The collision rate for 16 to 17-year-old GL novices was 50% lower than the rate for pre-GL novices during the 6 months after they received their learner's permits, and about 10% lower during their first 2 years of licensure when unsupervised driving from midnight to 5 A.M. was prohibited. Much of this improvement for 16 to 17-year-olds occurred during restricted night hours. Collision rates also were lower during nonrestricted hours in the initial 6 months of licensure. The 3-month "time discount" for driver education provided no safety benefit, and GL novices with driver education had collision rates that were not lower than pre-GL novices. There was no long-term effect found for the program after 16 to 17-year-olds graduated to full licensure. For older beginning drivers, crash rates during the first year after obtaining a learner's permit showed a 31% reduction. This effect diminished rapidly. There was only a 2% reduction during the first year of licensure, and crash rates increased during the following 2 years. Overall the data indicate substantial benefits of graduated licensing for 16 to 17-year-old beginners, but no benefits beyond the learner stage for older beginners.