Alkane biodegradation and dynamics of phylogenetic subgroups of sulfate-reducing bacteria in an anoxic coastal marine sediment artificially contaminated with oil

For 503 days, unoiled control and artificially oiled sediments were incubated in situ at 20m water depth in a Mediterranean coastal area. Degradation of the aliphatic fraction of the oil added was followed by GC-MS. At the same time, terminal restriction fragment length polymorphism (T-RFLP) of 16S rRNA encoding genes was used to detect dynamics in the sulfate-reducing bacteria (SRB) community in response to the oil contamination. Specific polymerase chain reaction (PCR) primer sets for five generic or suprageneric groups of SRB were used for PCR amplification of DNA extracted from sediments. During the experiment, hydrocarbons from C(17) to C(30) were significantly degraded even in strictly anoxic sediment layers. Of the five SRB groups, only two groups were detected in the sediments (control and oiled), namely the Desulfococcus-Desulfonema-Desulfosarcina-like group and the Desulfovibrio-Desulfomicrobium-like group. Statistical analysis of community patterns revealed dynamic changes over time within these two groups following the contamination. Significant differences in community patterns were recorded in artificially oiled compared with control sediments. Cloning and sequencing of 16S rRNA encoding genes performed after 503 days showed that many of the most abundant sequences were closely related to hydrocarbonoclastic SRB which could have played an active role in the observed biodegradation of aliphatic hydrocarbons. Results from the present study provide useful information on the dynamics of dominant SRB in heavily oil-contaminated sediments and their potential for anaerobic biodegradation for the treatment of spilled oil in anoxic marine environments.     

Incorporation of inositol hexaphosphate into intact red blood cells

Fluid charged lipid vesicles loaded with an inositol hexaphosphate solution were used to transport this allosteric effector into human intact red blood cells. Rate and extent of uptake of the vesicles and of the effector by the red blood cells were measured as changes in the O2 half-saturation pressure and the 31P-NMR spectra of the intracellular inositol hexaphosphate-haemoglobin complex.     

Decomposition and decoupling analysis of carbon dioxide emissions in African countries during 1984‒2014

The potential for mitigating climate change is growing worldwide, with an increasing emphasis on reducing CO₂ emissions and minimising the impact on the environment. African continent is faced with the unique challenge of climate change whilst coping with extreme poverty, explosive population growth and economic difficulties. CO₂ emission patterns in Africa are analysed in this study to understand primary CO₂ sources and underlying driving forces further. Data are examined using gravity model, logarithmic mean divisia index and Tapio's decoupling indicator of CO₂ emissions from economic development in 20 selected African countries during 1984?2014. Results reveal that CO₂ emissions increased by 2.11% (453.73 million ton) over the research period. Gravity centre for African CO₂ emissions had shifted towards the northeast direction. Population and economic growth were primary driving forces of CO₂ emissions. Industrial structure and emission efficiency effects partially offset the growth of CO₂ emissions. The economic growth effect was an offset factor in central African countries and Zimbabwe due to political instability and economic mismanagement. Industrial structure and emission efficiency were insufficient to decouple economic development from CO₂ emissions and relieve the pressure of population explosion on CO₂ emissions in Africa. Thus, future efforts in reducing CO₂ emissions should focus on scale-up energy-efficient technologies, renewable energy update, emission pricing and long-term green development towards sustainable development goals by 2030.     

A Framework to Predict the Impacts of Shale Gas Infrastructures on the Forest Fragmentation of an Agroforest Region

We propose a framework to facilitate the evaluation of the impacts of shale gas infrastructures (well pads, roads, and pipelines) on land cover features, especially with regards to forest fragmentation. We used a geographic information system and realistic development scenarios largely inspired by the PA (United States) experience, but adapted to a region of QC (Canada) with an already fragmented forest cover and a high gas potential. The scenario with the greatest impact results from development limited by regulatory constraints only, with no access to private roads for connecting well pads to the public road network. The scenario with the lowest impact additionally integrates ecological constraints (deer yards, maple woodlots, and wetlands). Overall the differences between these two scenarios are relatively minor, with <1 % of the forest cover lost in each case. However, large areas of core forests would be lost in both scenarios and the number of forest patches would increase by 13–21 % due to fragmentation. The pipeline network would have a much greater footprint on the land cover than access roads. Using data acquired since the beginning of the shale gas industry, we show that it is possible, within a reasonable time frame, to produce a robust assessment of the impacts of shale gas extraction. The framework we propose could easily be applied to other contexts or jurisdictions.     

Specification of the logit model: The case of valuation of nonmarket goods

We address the proper specification of the logit model for estimation of nonmarket commodity demand. Economic theory is used to show the conditions which must be met by the logit functional form if it is to yield valid estimates of welfare change measures and demand relationships. An empirical example is used to illustrate the argument. Recreational boating data were collected using the contingent valuation method (CVM) in Texas. In one instance the demand curve is positively sloped due to the specific functional form chosen. The estimated demand curve for the theoretically preferred functional form has the expected negative slope.     

II. Enhancement of gas transport in inositol hexaphosphate-loaded red blood cells

The gas-transport function of red blood cells which have incorporated inositol hexaphosphate is significantly improved by fusion with effector-loaded lipid vesicles. “Right-shifts” of the O₂-binding curves of inositol hexaphosphate-loaded red blood cells with half-saturation pressures at 37 °C up to 98 mmHg are observed. The transformation of 56% of the intracellular haemoglobin into the low affinity state corresponds to an optimum increase of the O₂-release capacity of 270%. The CO₂ transport is also correspondingly enhanced. The treated red blood cells show no inositol hexaphosphate depletion during a reasonable time.     

Process design of Synthetic Natural Gas (SNG) production using wood gasification

The process design of a 10–20 MW_th Synthetic Natural Gas (SNG) production process from wood has been performed. Combining process modelling and process integration techniques, this study proceeds via the following stages:

• thermodynamic modelling: mass, energy balances and simulation of the wood gasification, the methanation and the purification units;

• process integration that identifies the energy saving opportunities and prepares a thermo-economic optimization.

This work demonstrates that the process can transform wood into pipeline quality methane with a thermal efficiency of 57.9% based on the Lower Heating Value (LHV). The process integration study shows that the heat surplus of the process can be used to almost satisfy the mechanical work required by the process; only 7% of the mechanical needs should come from an external source.