Factors associated with multiple-pass procedures during chorionic villus sampling: A video analysis

Multiple placental passes during chorionic villus sampling (CVS) increase the risk of fetal loss; however, specific factors that predispose to repeat aspiration have not been delineated. To identify anatomic and technical variables associated with multiple-pass procedures, a detailed review of 205 videotaped CVS procedures (single pass = 163; multiple pass = 42) was performed, blinded to pregnancy outcome. The route of sampling did not influence the need for multiple aspiration attempts (transabdominal—30/ 135; transcervical—12/70), nor was placental location alone discriminatory. However, the combination of a posterior placenta and uterine retroversion was observed more frequently in the multiple-pass cohort (8/42 vs. 9/163; p<0.05). In transabdominal cases, suboptimal needle placement (e.g., perpendicular to the placental long axis) was more common in the initial aspiration of a multiple-pass procedure (21/30 vs. 38/105;p<0.01), while limited penetration of the catheter tip (e.g., just inside the placental edge) characterized a majority of multiple-pass cases in the transcervical subset (7/12 vs. 3/58; p<0.0001). A case-control cohort was constructed to evaluate the impact of these technical variables on sampling efficacy, independent of the influence of uterine position and placental site. In that analysis, suboptimal location and/or orientation of the sampling device remained characteristic of multiple-pass cases. We conclude that further reduction in the frequency of multiple-pass procedures might be achieved by consistent placement of the device tip in the central placental mass. Unlike amniocentesis, where any point of amnion entry will suffice, this technical nuance should be emphasized with CVS to maximize the single-pass success rate.     

Vegetation changes in Conservation Reserve Program lands in interior Alaska

Over 14 million hectares of erosion prone cropland in the United States has been converted into grasslands through the Conservation Reserve Program (CRP) administered by the United States Department of Agriculture, however, studies of the effects of CRP enrollment on plant communities and subsequent plant succession are largely lacking. In Delta Junction, Alaska plant communities in CRP fields are transitioning from grasslands to shrub dominated plant communities, which are resulting in compliance problems with program regulations that state “fields must be maintained in a condition that permits easy conversion to cropland”. To determine plant succession and how previous land management and soils might influence the transition, we measured plant populations in 20 CRP fields throughout Delta Junction using modified-Whittaker plots. These data were combined with data on current management practices, previous farming history, soils, soil properties, diversity indices, and time since land was cleared and analyzed with nonmetric multidimensional scaling ordination to determine factors that influence plant succession. Time in the CRP was the only factor consistently influencing plant succession. As time in the CRP increased, the planted introduced grasses brome grass (Bromus inermis) and red fescue (Festuca rubra) and the native pteridophyte (Equisetum arvense) decreased, whereas a native grass (Calamigrostis canadensis), five native forb, two native shrub, and three native tree species increased. Plant diversity increased at a rate of more than 2 species per 1000 m² per year. Regression analyses of plant species and plant groups using time in the CRP as the dependent variable resulted in the identification of outlier CRP fields with significantly more or less than expected covers of vegetation. All fields with these outliers had reasonable explanations for the differences in cover that were unrelated to the overall rate of plant succession. Current management practices will result in incompliant fields and different management practices that result in woody vegetation control is key to maintaining CRP fields in compliance.     

Challenges to achieving a successful transition to a low carbon economy in South Africa: examples from poor urban communities

South Africa faces several development challenges including those linked to climate change. Energy usage in South Africa, for example, is already constrained because of a range of development challenges (the dependence on cheap coal as a heating source; energy availability; access; affordability of alternative energy sources; and a range of health impacts, including air pollution). Notwithstanding calls for a transition to a low carbon economy, there have been few, recent assessments in South Africa of the costs associated with such a transition, particularly the social and economic costs for the poor who use energy in a variety of ways. In this paper we focus on trying to unravel some of the complex energy-use behaviour including understanding what drives consumers in resource-poor areas to choose and use persistently risky energy options. Analysis of qualitative data in two township areas, Doornkop and Kwaguqa, shows that township households, whether electrified or not, continue to burn coal. In both study areas, an estimated 80% of electrified households burn coal for space heating and cooking and also make use of multiple fuel sources for a range of activities. Although the major obstacles preventing people from discontinuing domestic coal combustion are poverty, the ready availability and social acceptability of coal together with other social customs cannot be underrated. This paper therefore highlights some of the persistent challenges associated with sustainable energy transitions in South Africa including implications for improved mitigation and adaptation for the energy sector in wider climate change efforts.     

Protozoan colonization on artificial substrates in relation to water quality in a tropical Indian harbour.

A field study was conducted to evaluate the protozoan colonization patterns on artificial substrates in relation to organic pollution within a tropical harbour. The composition of protozoans and their succession rates on artificial substrates(polyurethane foam units) were compared between two field stations(A and B), and their presence were considered with regards to the prevailing water quality conditions at the study sites. Altogether 44 genera of flagellates and ciliates were documented. The common genera of flagellates encountered included Monas, Polytoma, and Chromalina. Among the ciliates, the predominant genera were Tetrahymena, Vorticella, Lagymophyra, and Heloiphyra. These groups exhibited characteristic successional patterns in relation to ambient water quality. At Station A, located close to the sewage outfall, the water quality parameters included poor Secchi-disc transparency(0.48 m), dissolved oxygen of 1.93 mg/ml, salinity of 18 psu, and temperature 31.3 degrees C. Here, the nanoflagellates (spumella) colonized first, followed by microcilliate(Tetrahymena) and sessile form(Vorticella). Station B, located on the seaward side, was characterized by relatively less-stressed environmental conditions with transparency 1.85 m and dissolved oxygen value of 6.04 mg/ml. Salinity of 27.27 psu, and mean temperature of 30 degrees C were recorded at "B". At this station, the nanoflagellate Polytoma was first documented to colonize on the substrates, followed by microcilliate(Lagynophrya) and suctorid(Heliophyra). These findings support the use of protozoans as indicator species for evaluating the hazards posed by organic pollution to natural estuarine communities.     

Characteristics of urban ozone level in Hong Kong

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Carbon mitigation potential and costs of forestry options in Brazil,China, India,Indonesia, Mexico,the Philippines and Tanzania

This paper summarizes studies of carbon (C) mitigation potential and costs of about 40 forestry options in seven developing countries. Each study uses the same methodological approach – Comprehensive Mitigation Assessment Process (COMAP) – to estimate the above parameters between 2000 and 2030. The approach requires the projection of baseline and mitigation land-use scenarios. Coupled with data on a per ha basis on C sequestration or avoidance, and costs and benefits, it allows the estimation of monetary benefit per Mg C, and the total costs and carbon potential. The results show that about half (3.0 Pg C) the cumulative mitigation potential of 6.2 Petagram (Pg) C between 2000 and 2030 in the seven countries (about 200× 10⁶ Mg C yr^-1) could be achieved at a negative cost and the remainder at costs ranging up to $100 Mg C^-1. About 5 Pg C could be achieved, at a cost less than $20 per Mg C. Negative cost potential indicates that non-carbon revenue is sufficient to offset direct costs of these options. The achievable potential is likely to be smaller, however, due to market, institutional, and sociocultural barriers that can delay or prevent the implementation of the analyzed options.