Biofuels: Thermodynamic sense and nonsense

Much of the current enthusiasm for biofuels appears to ignore basic thermodynamic and other constraints.The fundamental problem with growing fuel is that combustible plant matter is almost invariably solid, while the major demand for energy at present is in the form of gas or liquid fuels. All current conversion processes are of low efficiency even for the convertible parts of the plant. For example the energy which could be obtained from burning a kilogram of wheat grain is about twice that available from the ethanol into which it can be converted by fermentation. Furthermore, all current liquid fuel processes can use only part of the plant.This paper highlights biofuel technologies which make sense, such as co-firing straw with coal in power stations, and those which because of thermodynamic considerations are nonsense, such as making ethanol from grain in Europe or from maize in the USA.Since arable land is a scarce resource in most of Europe, locally grown biofuels are unlikely to become a major replacement for fossil fuels. Strategies which can help to maximise this contribution are suggested, and promising, emerging technologies are highlighted.     

Evaluation and classification of severity for 176 genes on an expanded carrier screening panel

Background

Disease severity is important when considering genes for inclusion on reproductive expanded carrier screening (ECS) panels. We applied a validated and previously published algorithm that classifies diseases into four severity categories (mild, moderate, severe, and profound) to 176 genes screened by ECS. Disease traits defining severity categories in the algorithm were then mapped to four severity-related ECS panel design criteria cited by the American College of Obstetricians and Gynecologists (ACOG).

Methods

Eight genetic counselors (GCs) and four medical geneticists (MDs) applied the severity algorithm to subsets of 176 genes. MDs and GCs then determined by group consensus how each of these disease traits mapped to ACOG severity criteria, enabling determination of the number of ACOG severity criteria met by each gene.

Results

Upon consensus GC and MD application of the severity algorithm, 68 (39%) genes were classified as profound, 71 (40%) as severe, 36 (20%) as moderate, and one (1%) as mild. After mapping of disease traits to ACOG severity criteria, 170 out of 176 genes (96.6%) were found to meet at least one of the four criteria, 129 genes (73.3%) met at least two, 73 genes (41.5%) met at least three, and 17 genes (9.7%) met all four.

Conclusion

This study classified the severity of a large set of Mendelian genes by collaborative clinical expert application of a trait-based algorithm. Further, it operationalized difficult to interpret ACOG severity criteria via mapping of disease traits, thereby promoting consistency of ACOG criteria interpretation.

     

Potential climate change impacts on Atlantic cod (Gadus morhua) off the northeastern USA

We examined the potential impacts of future climate change on the distribution and production of Atlantic cod (Gadus morhua) on the northeastern USA’s continental shelf. We began by examining the response of cod to bottom water temperature changes observed over the past four decades using fishery-independent resource survey data. After accounting for the overall decline in cod during this period, we show that the probability of catching cod at specified locations decreased markedly with increasing bottom temperature. Our analysis of future changes in water temperature was based on output from three coupled atmosphere–ocean general circulation models under high and low CO₂ emissions. An increase of <1.5°C is predicted for all sectors under the low emission scenario in spring and autumn by the end of this century. Under the high emission scenario, temperature increases range from ～2°C in the north to >3.5°C in the Mid-Atlantic Bight. Under these conditions, cod appear vulnerable to a loss of thermal habitat on Georges Bank, with a substantial loss of thermal habitat farther south. We also examined temperature effects on cod recruitment and growth in one stock area, the Gulf of Maine, to explore potential implications for yield and resilience to fishing. Cod survival during the early life stages declined with increasing water temperatures, offsetting potential increases in growth with warmer temperatures and resulting in a predicted loss in yield and increased vulnerability to high fishing mortality rates. Substantial differential impacts under the low versus high emission scenarios are evident for cod off the northeastern USA.     

A reaction-based paradigm to model reactive chemical transport in groundwater with general kinetic and equilibrium reactions

This paper presents a reaction-based water quality transport model in subsurface flow systems. Transport of chemical species with a variety of chemical and physical processes is mathematically described by M partial differential equations (PDEs). Decomposition via Gauss-Jordan column reduction of the reaction network transforms M species reactive transport equations into two sets of equations: a set of thermodynamic equilibrium equations representing N(E) equilibrium reactions and a set of reactive transport equations of M-N(E) kinetic-variables involving no equilibrium reactions (a kinetic-variable is a linear combination of species). The elimination of equilibrium reactions from reactive transport equations allows robust and efficient numerical integration. The model solves the PDEs of kinetic-variables rather than individual chemical species, which reduces the number of reactive transport equations and simplifies the reaction terms in the equations. A variety of numerical methods are investigated for solving the coupled transport and reaction equations. Simulation comparisons with exact solutions were performed to verify numerical accuracy and assess the effectiveness of various numerical strategies to deal with different application circumstances. Two validation examples involving simulations of uranium transport in soil columns are presented to evaluate the ability of the model to simulate reactive transport with complex reaction networks involving both kinetic and equilibrium reactions.     

Spatial and temporal variability of greenhouse gas emissions from rural development land use operations

Climate change objectives of mitigation and adaptation are being mainstreamed into many policies and strategies around the world. In Europe, this has included the Rural Development Programme, which aims to tackle multiple social, economic and environmental objectives in rural areas, and the integration of climate change objectives adds another strand of complexity to the decision making process. When formulating policies determining the likely effectiveness of any particular measure can be challenging, especially with respect to the spatial and temporal variability of greenhouse gas emissions. This is a challenge faced by all countries and regions around the world. This study uses Europe as an example to explore this issue. It highlights the variability in emissions from land use operations that may be encountered under different conditions and time horizons and considers this in the context of policy formulation. The Optimal Strategies for Climate change Action in Rural Areas software has been adapted to derive net greenhouse gas emissions for rural development operations for all regions in Europe. Operations have been classified into five categories based on their benefit/burden over different time horizons. The analysis shows that it is important to understand the time period over which benefits or burdens are realised and determine how this fits with policy instruments, such as land management agreements and the permanency of actions. It also shows that in some regions an operation can have benefits, but in other regions it has burdens; thus, location can be critical. Finally, in the context of developing operations to meet multiple social, economic and environmental objectives, it is important to acknowledge that seeking options that only reduce emissions may not always be practical or possible. In some instances, we may have to accept an increase in emissions in order to meet other objectives. It is important that we evaluate the net greenhouse gas emissions of all operations, not just those aimed at climate change mitigation. We can then select those with the least burden in the process of developing optimal solutions to meet multiple objectives.     

Case study: Business tailored management system verification (BTMSV©) for responsible care®

This article describes the development, use, and learning from a Business Tailored Management System Verification (BTMSV) process. This process is designed to focus on selected Responsible Care activities or programs, and provides broad options to include specific elements to meet more targeted business unit objectives. © 1998 John Wiley & Sons, Inc.