Evaluation of amniotic fluid cell filtration: An experimental approach to early amniocentesis

Prior to a prospective application of amniotic fluid (AF) cell filtration to early amniocentesis, we tested the technique on a surplus from mid-trimester samples. By using the same sample size of 5 ml in experiments with a filter and in routine diagnostic procedures (control), we evaluated an optimal filter system. The prolonged culture time of filtered cells and the reduced number of clones are most probably due to mechanical stress (filtration pressure), whereas loss of the cells by adhesion to the filter system, and an AF-free culture medium (growth factors) are suggested to be less important. The AF cells are very sensitive to mechanical stress. Slow filtration (⩽3 ml AF/min) through filters with a high porosity and the largest possible pore size should be preferred. A mixed cellulose ester filter membrane with a pore size of 5·0 μm proved to be the most efficient, allowing harvest of the filtered cells after only a slight prolongation of the culture time (+2·4 days) compared with unfiltered aliquots. A filter set with a bypass connected by three-way taps allows cell filtration during either aspiration or reinjection of the AF. Cell filtration after amniocentesis and consecutive reverse flushing of the membrane with the appropriate amount of culture medium proved to be the best with regard to easy handling and reducing the risk of bacterial contamination.     

Living in a “stethoscope”: burrow-acoustics promote auditory specializations in subterranean rodents

Subterranean mammals rely to a great extent on audition for communication and to be alerted to danger. The only hitherto published report on burrow acoustics revealed that in tunnels of blind mole-rats (Spalax ehrenbergi), airborne sounds of 440 Hz propagated best whereas lower and higher frequencies were effectively attenuated. Morpho-functional analyses classify the ear of subterranean mammals as a low-sensitivity and low-frequency device. Concordantly, hearing is characterized by low sensitivity and a restricted frequency range tuned to low frequencies (0.5–4 kHz). Some authors considered the restricted hearing in subterranean mammals vestigial and degenerate due to under-stimulation. In contrast to this view stand a rich (mostly low-frequency) vocal repertoire and progressive structural specializations of the middle and inner ear. Thus, other authors considered these hearing characteristics adaptive. To test the hypothesis that acoustical environment in burrows of different species of subterranean mammals is similar, we measured sound attenuation in burrows of Fukomys mole-rats (formerly known as Cryptomys, cf. Kock et al. 2006) of two differently sized species at different locations in Zambia. We show that in these burrows, low-frequency sounds (200–800 Hz) are not only least attenuated but also their amplitude may be amplified like in a stethoscope (up to two times over 1 m). We suggest that hearing sensitivity has decreased during evolution of subterranean mammals to avoid over-stimulation of the ear in their natural environment. We dedicate this work to Mathias Kawalika, who died in March 2006.     

Waste disposal technology transfer matching requirement clusters for waste disposal facilities in China

Even though technology transfer has been part of development aid programmes for many decades, it has more often than not failed to come to fruition. One reason is the absence of simple guidelines or decision making tools that help operators or plant owners to decide on the most suitable technology to adopt. Practical suggestions for choosing the most suitable technology to combat a specific problem are hard to get and technology drawbacks are not sufficiently highlighted. Western counterparts in technology transfer or development projects often underestimate or don’t sufficiently account for the high investment costs for the imported incineration plant; the differing nature of Chinese MSW; the need for trained manpower; and the need to treat flue gas, bunker leakage water, and ash, all of which contain highly toxic elements.This article sets out requirements for municipal solid waste disposal plant owner/operators in China as well as giving an attribute assessment for the prevalent waste disposal plant types in order to assist individual decision makers in their evaluation process for what plant type might be most suitable in a given situation. There is no ‘best’ plant for all needs and purposes, and requirement constellations rely on generalisations meaning they cannot be blindly applied, but an alignment of a type of plant to a type of owner or operator can realistically be achieved. To this end, a four-step approach is suggested and a technology matrix is set out to ease the choice of technology to transfer and avoid past errors. The four steps are (1) Identification of plant owner/operator requirement clusters; (2) Determination of different municipal solid waste (MSW) treatment plant attributes; (3) Development of a matrix matching requirement clusters to plant attributes; (4) Application of Quality Function Deployment Method to aid in technology localisation.The technology transfer matrices thus derived show significant performance differences between the various technologies available. It is hoped that the resulting research can build a bridge between technology transfer research and waste disposal research in order to enhance the exchange of more sustainable solutions in future.     

Sewage sludge composting: Influence of initial mixtures on organic matter evolution and N availability in the final composts

The influence of bulking agents on organic matter (OM) stability and nitrogen (N) availability in sewage sludge composts was investigated. The same sludge was composted on an industrial plant with different mixtures of bulking agents. The composting process included an active phase and a curing phase, both lasting 6 weeks, separated by the screening of composts. The OM evolution was characterised by carbon (C) and N mass balances in biochemical fractions. The OM stability and N potential availability of final composts were measured during soil incubations. During composting, the C and N losses reached more than 62% of the initial C and more than 45% of the initial N, respectively, due to C mineralisation or N volatilisation and screening. The bulking materials mostly influenced OM evolution during the active phase. They contributed to the mitigation of N losses during the active phase where N immobilisation through active microbial activity was favoured by bulking agents increasing the C:N ratio of the initial mixtures. However, the influence of bulking agents on OM evolution was removed by the screening; this induced the homogenisation of compost characteristics and led to the production of sludge composts with similar organic matter characteristics, C degradability and N availability.     

Blue space: The importance of water for preference,affect, and restorativeness ratings of natural and built scenes

Although theorists have suggested that aquatic environments or “blue space” might have particular restorative potential, to date there is little systematic empirical research on this issue. Indeed the presence of water has, unintentionally, been a confounding factor in research comparing people’s reactions to built and natural environments. Whereas aquatic features (rivers, lakes, coasts) are frequently present in visual stimuli representing natural environments they are rarely incorporated in stimuli portraying built environments. As many towns are, for good reason, located near water this is a potentially significant oversight. The current research collated a set of 120 photographs of natural and built scenes, half of which contained “aquatic” elements. Proportions of “aquatic”/“green”/“built” environments in each scene (e.g. 1/3rd, 2/3rds) were also standardised. Two studies investigated preferences (attractiveness, willingness to visit and willingness to pay for a hotel room with the view), affect and perceived restorativeness ratings for these photographs. As predicted, both natural and built scenes containing water were associated with higher preferences, greater positive affect and higher perceived restorativeness than those without water. Effect sizes were consistently large. Intriguingly, images of “built” environments containing water were generally rated just as positively as natural “green” space. We propose a number of avenues for further research including exploration of the mechanisms underlying these effects.     

Reproductive functions of wild fish as bioindicators of reproductive toxicants in the aquatic environment

Background, aim, and scope  

Impacts on the reproductive health of wild fish are thought to be suitable early-warning tools indicating contamination of surface waters with endocrine-disrupting compounds. Ecotoxicological assessment of these field observations depends on the availability of reliable biomarkers to enable a discrimination of natural variations of reproductive functions from anthropogenic impacts.     

Spatial relationships between nitrogen status and pitch canker disease in slash pine planted adjacent to a poultry operation

Pitch canker disease (Fusarium circinatum Nirenberg & O'Donnell) causes serious shoot dieback, reduced growth and mortality in pines found in the southern and western USA, and has been linked to nutrient imbalances. Poultry houses with forced-air ventilation systems produce nitrogen (N) emissions. This study analyzed spatial correlations between pitch canker disease and foliar, forest floor, soil, and throughfall N in a slash pine (Pinus elliottii var. elliottii Engelm.) plantation adjacent to a poultry operation in north Florida, USA. Tissue and throughfall N concentrations were highest near the poultry houses and remained elevated for 400 m. Disease incidence ranged from 57-71% near the poultry houses and was spatially correlated with N levels. Similarly, stem mortality ranged from 41-53% in the most heavily impacted area, and declined to 0-9% at distances greater than 400 m. These results suggest that nutritional processes exacerbate changes in disease susceptibility and expression in slash pine.     

Robust Energy Portfolios Under Climate Policy and Socioeconomic Uncertainty

Concerning the stabilization of greenhouse gases, the UNFCCC prescribes measures to anticipate, prevent, or minimize the causes of climate change and mitigate their adverse effects. Such measures should be cost-effective and scientific uncertainty should not be used as a reason for postponing them. However, in the light of uncertainty about climate sensitivity and other underlying parameters, it is difficult to assess the importance of different technologies in achieving robust long-term climate risk mitigation. One example currently debated in this context is biomass energy, which can be used to produce both carbon-neutral energy carriers, e.g., electricity, and at the same time offer a permanent CO₂ sink by capturing carbon from the biomass at the conversion facility and permanently storing it. We use the GGI Scenario Database IIASA [3] as a point of departure for deriving optimal technology portfolios across different socioeconomic scenarios for a range of stabilization targets, focusing, in particular, on new, low-emission scenarios. More precisely, the dynamics underlying technology adoption and operational decisions are analyzed in a real options model, the output of which then informs the portfolio optimization. In this way, we determine the importance of different energy technologies in meeting specific stabilization targets under different circumstances (i.e., under different socioeconomic scenarios), providing valuable insight to policymakers about the incentive mechanisms needed to achieve robust long-term climate risk mitigation.