Potential For Future Production Research Articles

Screening of white-rot fungi manganese peroxidases: a comparison between the specific activities of the enzyme from different native producers

In this study manganese peroxidase (MnP) enzymes from selected white-rot fungi were isolated and compared for potential future recombinant production. White-rot fungi were cultivated in small-scale in liquid media and a simplified process was established for the purification of extracellular enzymes.Five lignin degrading organisms were selected (Bjerkandera sp., Phanerochaete (P.) chrysosporium, Physisporinus (P.) rivulosus, Phlebia (P.) radiata and Phlebia sp. Nf b19) and studied for MnP production in small-scale. Extracellular MnP activity was followed and cultivations were harvested at proximity of the peak activity. The production of MnPs varied in different organisms but was clearly regulated by inducing liquid media components (Mn2+, veratryl alcohol and malonate). In total 8 different MnP isoforms were purified.Results of this study reinforce the conception that MnPs from distinct organisms differ substantially in their properties. Production of the extracellular enzyme in general did not reach a substantial level. This further suggests that these native producers are not suitable for industrial scale production of the enzyme. The highest specific activities were observed with MnPs from P. chrysosporium (200 U mg-1), Phlebia sp. Nf b19 (55 U mg-1) and P. rivulosus (89 U mg-1) and these MnPs are considered as the most potential candidates for further studies. The molecular weight of the purified MnPs was estimated to be between 45–50 kDa.

Integration of Production Analysis and Rate/Time Analysis by Use of Parametric Correlations - Theoretical Considerations and Practical Applications

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 140556, ’Integration of Production Analysis and Rate/ Time Analysis by Use of Parametric Correlations - Theoretical Considerations and Practical Applications,’ by D. Ilk, SPE, Texas A&M University/DeGolyer and MacNaughton; J.A. Rushing, SPE, Apache Corporation; and T.A. Blasingame, SPE, Texas A&M University, prepared for the 2011 SPE Hydraulic Fracturing Technology Conference and Exhibition, The Woodlands, Texas, 24-26 January. The paper has not been peer reviewed. Well-performance analysis in unconventional reservoirs is a challenging task because of the nonuniqueness associated with estimating well and formation properties. Also, estimating of reserves can be uncertain because of the very long transient-flow periods. Recent semiempirical rate/time relations have been shown to model the rate/time behavior properly for wells in unconventional reservoirs. This study focused on finding theoretical and empirical relationships of rate/time-model parameters with well and formation properties. Introduction Unconventional-reservoir systems (e.g., tight-gas-sand, shale-gas, tight/shale-oil, and coalbed-methane reservoirs) have become a significant source of hydrocarbon production, and they offer high potential for reserves growth and future production. Complex geological and petrophysical systems describe unconventional reservoirs in addition to heterogeneities at all scales similar to conventional-reservoir systems. Because of the low-to-ultralow permeability, well-stimulation operations (e.g., single or multistage hydraulic fracturing) are required to establish production at commercial rates. Analytical and semianalytical modeling of horizontal wells connected to multiple transverse fractures is important in terms of diagnosing well-performance behavior. At early time, the dominant flow is linear (perpendicular to the fracture face) until pressure transients of the individual fractures begin to interfere, leading to a compound-linear-flow regime. A semianalytical solution can model the entire range of flow regimes surrounding a horizontal well with multiple fractures. The solution includes a dual-permeability region near fracture faces to represent the complex fractured region surrounding the primary planar hydraulic fractures. Reserves estimation for unconventional-reservoir systems has been performed primarily by use of conventional Arps’ decline-curve relations. Application of Arps’ relations (specifically the hyperbolic relation) for reserves estimates yields significant overestimates of reserves because Arps’ relations are applicable only during a boundary-dominated-flow regime, whereas unconventional-reservoir systems exhibit extremely long transient-flow periods. Recently, two rate/time relations were introduced to estimate reserves in unconventional reservoirs in the form of the “stretched exponential function.” These relations have proved to be successful in modeling the rate/time behavior properly, and these relations provide consistent and more-realistic reserves estimates compared with Arps’ decline relations.

Wurtzite Al xGa 1− xN bulk crystals grown by molecular beam epitaxy

We have studied the growth of wurtzite GaN and Al x Ga 1− x N layers and bulk crystals by molecular beam epitaxy (MBE). MBE is normally regarded as an epitaxial technique for the growth of very thin layers with monolayer control of their thickness. However, we have used the MBE technique for bulk crystal growth and have produced 2 in diameter wurtzite Al x Ga 1− x N layers up to 10 μm in thickness. Undoped wurtzite Al x Ga 1− x N films were grown on GaAs (1 1 1)B substrates by a plasma-assisted molecular beam epitaxy (PA-MBE) method and were removed from the GaAs substrate after the growth. The fact that free-standing ternary Al x Ga 1− x N wafers can be grown is very significant for the potential future production of wurtzite Al x Ga 1− x N substrates optimized for AlGaN-based device structures.

Simulation of the Effect of Intensive Forest Management on Forest Production in Sweden

The effects of intensifying the management of 15% of the Swedish forest land on potential future forest production over a 100-year period were investigated in a simulation study. The intensive management treatments, which were introduced over a period of 50 years, were: intensive fertilization of Norway spruce (IntFert); bulking-up Norway spruce elite populations using somatic embryogenesis (SE-seedlings); planting of lodgepole pine, hybrid larch, and Sitka spruce (Contorta, Larch, and Sitka); fertilization with wood ash on peatlands (Wood ash); and conventional fertilization in mature forests (ConFert). Potential sites for applying intensive forest management (IFM) to sites with low nature conservation values were determined with a nature conservation score (NCS). Four different scenarios were simulated: “Base scenario”, which aimed at reducing the negative impact on nature conservation values, “Fast implementation”, “No IntFert” (IntFert was not used), and “Large Forest Companies”, where the majority of plots were selected on company land. Total yields during the 100-year simulation period were about 85–92% higher for the intensive forest management scenarios than for the reference scenario (business as usual). In the “No IntFert” scenario total production was 1.8% lower and in the “Large Forest Companies” scenario total production was 4.8% lower than in the “Base scenario”. “Fast implementation” of IFM increased yield by 15% compared to the “Base scenario”. Norway spruce SE-seedlings and IntFert gave the highest yields, measured as total production during the 100-year simulation period, but relative to the yields in the reference scenario, the highest increases in yield were for Contorta. The “Base scenario” and “No IntFert” gave the highest yields for plots with the lowest NCS, but plots with higher NCS had to be used in the “Fast implementation” and “Large Forest Companies” scenarios. More than half of the effect on future growth of IFM methods was because of increased intensity in the regenerations. It took a relatively long time (40–60 years) for the simulated IFM treatments to result in a significant increase in stem volume production.

Quick development of an analytical enantioselective high performance liquid chromatography separation and preparative scale-up for the flavonoid Naringenin

The HPLC enantioselective separation of ( R/ S)-Naringenin, a chiral flavonoid found in several fruits juices and well-known for its beneficial health-related properties, including antioxidant, anti-inflammatory, cancer chemopreventive, immunomodulating and antimicrobial activities, has been performed on both analytical and (semi)-preparative scale using an amylose derived Chiralpak AD chiral stationary phase (CSP). A standard screening protocol for cellulose and amylose based CSPs was firstly applied to analytical Chiralcel OD-H and Chiralpak AD-H, as well as to Lux Cellulose-1, Lux Cellulose-2 and Lux Amylose-2 in order to identify the best experimental condition for the subsequent scaling-up. Using Chiralpak AD-H and eluting with pure methanol (without acidic or basic additives) relatively short retention times, high enantioselectivity and good resolution ( α = 1.49, R s = 3.48) were observed. Therefore, these experimental conditions were properly scaled-up to (semi)-preparative scale using both a pre-packed Regispack column and a Chiralpak AD column packed in house with bulk CSP. The developed preparative method proved to be superior to previously published methods in terms of elution times, separation and resolution and is suitable for obtaining a quick access to the desired enantiomers with high enantiomeric excess and amounts sufficient for biological investigations. Future scale-up options (enantioselective supercritical fluid chromatography or HPLC in the Simulated Moving Bed mode) were also evaluated. It could be shown that both methodologies have a high potential for future production of Naringenin enantiomers by enantioselective chromatography.

Laser Treatment of Organic Thin Film Solar Cells

ABSTRACTIn the last years more and more effort has been put into the development of thin-film organic solar cells using conductive and semi-conductive polymers. A great advantage of these polymers is the possibility to deposit them in high throughput print and coating processes. This feature provides huge potential for future production of low cost photovoltaics. While TCO layers form the transparent front contact, polymers are used for the buildup of the active layer and the design of the interface between active layer and front contact. The polymer materials have to be patterned in order to allow for a row connection of the solar cell work (typically by structured deposition, e.g. printing). In addition the bulk hetero junction (BHJ) of the active layer consisting of poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) requires an annealing step to optimize the layers structure and therewith the efficiency of the solar cell (typically by thermal treatment, e.g. oven). 3D-Micromac used ultra-short pulsed lasers to evaluate the applicability of various wavelengths for the selective ablation of the BHJ consisting of P3HT:PCBM on top of a Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and indium tin oxide (ITO) film system on glass substrates. The process of laser annealing was investigated using a short-pulsed laser with a wavelength close to the absorption maxima of the BHJ.

Model Simulations of the Hengill Area, Southwestern Iceland

The Hengill Area is an important energy source for Reykjavik and surrounding area, both for electricity and district space heating. Two production fields are located in the area: Nesjavellir and Hellisheiði. Two other potential production fields are believed to be in the area. We present a new conceptual model supported by numerical calculations for the entire Hengill Area. Calculations were performed using the \({{\tt TOUGH2}}\) software suite. The model contains nine layers consisting of 966 elements each (total of 8,964). Geological survey data, down-hole measurements, and production histories from the fields have been used to calibrate the model. The model has been used to predict how production will affect the geothermal fields. Information gathered throughout the production history, such as drawdown and changes in enthalpy, have been used to re-evaluate the size and the production capacity of the production fields. Different production scenarios, such as different energy throughput, have been simulated. The model simulations have also been used to estimate the capacity of potential future production fields.

Effect of Using an On-Farm Culture-Based Treatment System on Antibiotic Use and Bacteriological Cure for Clinical Mastitis

Mastitis remains the most costly infectious disease, and the most frequent cause of antibacterial use on commercial dairy farms. As such, research should continue on the development and validation of new management tools that will help reduce the health and economic impact of this disease, while at the same time promoting the judicious and strategic use of antimicrobials on dairy farms. The adoption of on-farm culture systems may allow producers to make more strategic mastitis treatment decisions, potentially reducing antimicrobial use while maintaining the future production potential of the cow. The objective of this study was to describe the effect of using an on-farm culture system to guide strategic treatment of clinical mastitis cases on intramammary antibiotic use and bacteriological cure rates in affected quarters.

The UK Biobank sample handling and storage protocol for the collection, processing and archiving of human blood and urine

UK Biobank is a large prospective study in the UK to investigate the role of genetic factors, environmental exposures and lifestyle in the causes of major diseases of late and middle age. Extensive data and biological samples are being collected from 500,000 participants aged between 40 and 69 years. The biological samples that are collected and how they are processed and stored will have a major impact on the future scientific usefulness of the UK Biobank resource. The aim of the UK Biobank sample handling and storage protocol is to specify methods for the collection and storage of participant samples that give maximum scientific return within the available budget. Processing or storage methods that, as far as can be predicted, will preclude current or future assays have been avoided. The protocol was developed through a review of the literature on sample handling and processing, wide consultation within the academic community and peer review. Protocol development addressed which samples should be collected, how and when they should be processed and how the processed samples should be stored to ensure their long-term integrity. The recommended protocol was extensively tested in a series of validation studies. UK Biobank collects about 45 ml blood and 9 ml of urine with minimal local processing from each participant using the vacutainer system. A variety of preservatives, anti-coagulants and clot accelerators is used appropriate to the expected end use of the samples. Collection of other material (hair, nails, saliva and faeces) was also considered but rejected for the full cohort. Blood and urine samples from participants are transported overnight by commercial courier to a central laboratory where they are processed and aliquots of urine, plasma, serum, white cells and red cells stored in ultra-low temperature archives. Aliquots of whole blood are also stored for potential future production of immortalized cell lines. A standard panel of haematology assays is completed on whole blood from all participants, since such assays need to be conducted on fresh samples (whereas other assays can be done on stored samples). By the end of the recruitment phase, 15 million sample aliquots will be stored in two geographically separate archives: 9.5 million in a -80 degrees C automated archive and 5.5 million in a manual liquid nitrogen archive at -180 degrees C. Because of the size of the study and the numbers of samples obtained from participants, the protocol stipulates a highly automated approach for the processing and storage of samples. Implementation of the processes, technology, systems and facilities has followed best practices used in manufacturing industry to reduce project risk and to build in quality and robustness. The data produced from sample collection, processing and storage are highly complex and are managed by a commercially available LIMS system fully integrated with the entire process. The sample handling and storage protocol adopted by UK Biobank provides quality assured and validated methods that are feasible within the available funding and reflect the size and aims of the project. Experience from recruiting and processing the first 40,000 participants to the study demonstrates that the adopted methods and technologies are fit-for-purpose and robust.

Sustainable agriculture: an explanation of a concept.

Close relationships between agriculture and many areas of human activity determine countless interlinkages with global issues of natural environment protection, human population increase, food supply, industry and world trade. This broad context promotes different perceptions of sustainable agriculture by different interest groups. Profitable diversification away from overproduction of basic commodities and satisfaction of environmental pressure groups are major preoccupations in developed countries. Elsewhere the main concerns is to maintain a trend of increasing production: food security with a future dimension. Achieving this depends essentially on protecting the agricultural resource base. Inputs and input substitution are important co-related issues but the core of sustainability is the avoidance of any attrition of the potential for future production; this demands that we guard soil, water sources, grazing lands and gene pools against loss and degradation. Though superficially biophysical or technical in nature, most problems of resource degradation and eroding potential are rooted in economic, social and political issues; few such problems will be solved unless the primacy of these issues is recognized and addressed. Sustainable agriculture will likely remain elusive until governments and other agencies accept it as arising only as the outcome of a synthesis of strategies on population, employment, economic planning, technical research and national investment.

Seismic Characterisation of Gas-rich Near Surface Sediments in the Arkona Basin, Baltic Sea

Gas in sediments has become an important subject of research for various reasons. It affects large areas of the sea floor where it is mainly produced. Gas and gas migration have a strong impact on the environmental situation as well as on sea floor stability. Furthermore, large research programs on gas hydrates have been initiated during the last 10 years in order to investigate their potential for future energy production and their climatic impact. These activities require the improvement of geophysical methods for reservoir investigations especially with respect to their physical properties and internal structures. Basic relationships between the physical properties and seismic parameters can be investigated in shallow marine areas as they are more easily accessible than hydrocarbon reservoirs. High-resolution seismic profiles from the Arkona Basin (SW Baltic Sea) show distinct ‘acoustic turbidity’ zones which indicate the presence of free gas in the near surface sediments. Total gas concentrations were determined from cores taken in the study area with mean concentrations of 46.5 ml/l wet sediment in non-acoustic turbidity zones and up to 106.1 ml/l in the basin centre with acoustic turbidity. The expression of gas bubbles on reflection seismic profiles has been investigated in two distinct frequency ranges using a boomer (600–2600 Hz) and an echosounder (38 kHz). A comparison of data from both seismic sources showed strong differences in displaying reflectors. Different compressional wave velocities were observed in acoustic turbidity zones between boomer and echosounder profiles. Furthermore, acoustic turbidity zones were differently characterised with respect to scattering and attenuation of seismic waves. This leads to the conclusion that seismic parameters become strongly frequency dependent due to the dynamic properties of gas bubbles.

Effect of Increasing Energy and Protein Intake on Mammary Development in Heifer Calves

The objective of this study was to determine if increased energy and protein intake from 2 to 14wk of age would affect mammary development in heifer calves. At 2wk of age, Holstein heifer calves were assigned to 1 of 4 treatments in a 2×2 factorial arrangement with 2 levels of protein and energy intake (moderate, M; high, H) in period 1 (2 to 8wk of age) and 2 levels of protein and energy intake (low, L; high, H) in period 2 (8 to 14wk of age), so that mean initial body weights were approximately equal for all 4 treatments (ML, MH, HL, and HH). The M diet in period 1 consisted of a standard milk replacer (21.3% CP, 21.3% fat) fed at 1.1% of BW on a DM basis and a 16.5% CP grain mix fed at restricted intake to promote 400g of daily gain, whereas the L diet in period 2 consisted only of the grain mix. The H diet in period 1 consisted of a high-protein milk replacer (30.3% CP, 15.9% fat) fed at 2.0% of body weight on a DM basis and a 21.3% CP grain mix available ad libitum. In period 2, the H diet consisted of just the 21.3% grain mix. Calves were gradually weaned from milk replacer by 7wk and slaughtered at 8 (n=11) or 14wk of age (n=41). Parenchyma from the distal region, midgland, and proximal region relative to the teat from one half of the udder was collected, fixed, and embedded in paraffin. The other half of the gland was used to determine parenchymal mass, protein, fat, DNA, RNA, and extraparenchymal mass. Total parenchymal tissue, parenchymal DNA, parenchymal RNA, and concentrations of DNA and RNA were higher for calves on the H diet during period 1, but were not affected by diet during period 2. Parenchymal fat percentage was increased by the H diet during period 2. The H diet increased extraparenchymal fat during both periods. The area of parenchyma occupied by epithelium was not affected by treatment, but at the end of period 2, the percentage of proliferating epithelial cells as indicated by Ki67, an marker of cell proliferation, expression was greater for calves on the M diet in period 1 compared with calves on the H diet in period 1. Diets did not influence parenchymal protein percentage or the ratio of RNA to DNA. Higher energy and protein intake from 2 to 8wk of age increased parenchymal mass and parenchymal DNA and RNA in mammary glands of heifer calves without increasing deposition of parenchymal fat. Diet also influenced histological development of mammary parenchyma and subsequent proliferation of ductal epithelial cells. Implications of these effects for future milk production potential are unknown.

Speeding Chemistry Along

C atalytic processes abound in nature. From enzymes to mineral surfaces, catalysts increase the rate of a given reaction, often by reducing the activation energy that the reactants must overcome before they go on to form products. Catalysts have been developed for a wide spectrum of reactions, with perhaps the most familiar example being the converter in cars used to reduce toxic emissions. This special issue of Science on catalysis focuses on efforts to understand and improve industrial catalysis. Most catalysts can be described as either homogeneous or heterogeneous. Homogeneous catalysts are molecularly dispersed with the reactants in the same phase, which provides easy access to the catalytic site but can make the separation of catalyst and products difficult. Heterogeneous catalysts—usually solids—are in a different phase from the reactants, which reduces separation problems but provides more limited access to the catalytic site. Cole-Hamilton (p. 1702) reviews recent efforts to facilitate the separation of homogeneous catalysts. Approaches include anchoring the catalyst to a soluble or insoluble support, which effectively “heterogenizes” the catalyst, and designing the catalyst so that it is soluble in a solvent that, under some conditions, does not mix with the reaction product. The classic heterogeneous catalyst contains nanoscale metal particles dispersed on a solid support such as aluminum oxide. Bell (p. [1688][1]) discusses how catalyst nanoparticles are synthesized and how particle size and shape affect reactivity. Cho's News story (p. 1684) describes how ordinarily inert gold becomes a useful catalyst when shrunk to nanoparticle size. Many solid-phase catalysts, such as highly crystalline zeolites, owe their high reactivity in part to their high surface area created by angstrom-scale microporosity. Rolison (p. [1698][2]) examines newer examples of microporous catalysts and argues that porosity itself is far more important than crystallinity. Enzymes have very high selectivities, which should allow the production of pure products, but several issues have limited their use in industrial synthesis. Schoemaker et al. (p. 1694) show how recent advances in directed evolution, high-throughput screening, metabolic engineering, and genomics are producing enzymes that can operate under the desired conditions and catalyze reactions that pose a challenge to synthetic homogeneous catalysts. Yoon and Jacobsen (p. [1691][3]) highlight a particular class of synthetic homogeneous catalyst. “Privileged” chiral catalysts can catalyze asymmetric reactions that proceed via different mechanisms and produce very different types of products. With two examples (salen complexes and cinchona alkaloids), they illustrate the diversity of products that are accessible with these catalysts. Alper's News story (p. 1686) describes efforts to develop inorganic catalysts from hydrogenases, which are enzymes with which living organisms make and unmake molecular hydrogen—reactions with huge potential for future energy production. Industrial catalysis will continue to require chemical engineers to take the work of chemists, and increasingly biologists, and run it efficiently on a grand scale. How well this interplay works in the United Kingdom as compared with how it works in the United States is discussed in an Editorial by Higgins (p. 1625). [1]: /lookup/doi/10.1126/science.1083671 [2]: /lookup/doi/10.1126/science.1082332 [3]: /lookup/doi/10.1126/science.1083622

Estimating the Ultimate Recoverable Reserves of the Paris Basin, France

The Paris Basin is a mature basin from an exploration point of view. More than 800 exploration wells have been drilled over the last 40 years and 52 fields have been discovered from which 33. 4 Mt of petroleum have been produced by the end 2000. Based on past production data, the future exploration and production potential of the Paris Basin is estimated using classical statistical methods. The mean size of a field in theParis Basin is about 100 000 t with a 5% chance of a field whose size is greater than 2. 5 Mt. The ultimate recoverable reserves based on the creaming curve analysis were about 15 Mt in 1986, 29 Mt in 1991 and 46 Mt in 1996. At present, there is a 5% chance of finding a field in the Dogger and Keuper formations that is bigger than 4 Mt. The drilling success ratio increases from 1/66 for the shallowest, the Cretaceous Neocomian formation to 1/8 in the deepest and latest to be drilled Triassic Keuper formation. The data analysis presented in the paper is based on known production data which do not take into account additional production gained by enhanced recovery methods or additional reserves added by discoveries based on new plays, that however may significantly increase reserves beyond the numbers presented here as the creaming curve analysis has shown.

Mixing Patterns and Plankton Biomass of the St. Lawrence Great Lakes under Climate Change Scenarios

This study is part of an assessment of potential effects of climate change on the St. Lawrence Great Lakes. Its purpose is to investigate potential future lake mixing patterns and primary production. Nested physical and biological models were applied to seasonal mixed layer depth, heat content, primary productivity, and to algal biomass measured as particulate chlorophyll. Two independent second generation General Circulation Models provided scenarios for future conditions of cloud cover, air temperature, humidity, and winds. The climate variables were used to force heat balance and surface mixed layer models for Lakes Superior, Michigan, Huron, Erie, and Ontario. Physical models of heat balance and mixed layer dynamics were coupled with a model of primary biological production and growth of phytoplankton. Simulated climate conditions were for time periods centered at 1975, 2030, 2050, and 2090. Climate projections from both GCMs lead to elevated mixed layer and bottom temperatures in all five lakes by as much as 5°C during this century. Both GCMs point to longer duration of thermal stratification in the five lakes, stronger stability of stratification, and deeper daily mixing depths during peak thermal stratification. For Lake Erie, no striking differences in algal biomass are likely according to climate projections of either model, but for the other lakes, either the duration of nutrient limitation of algal growth is projected to increase, or light limitation caused by deeper mixing is projected to limit the development of algal biomass.

Manufacture of colloidal polymer ellipsoids for anisotropic conducting nano-composites

This project aimed to make anisotropic conducting nano-composites based on a segregated system of 20 nm gold particles and deformed polyethylene spheres of colloidal size. Two methods for achieving the deformation of the colloidal polyethylene spheres were attempted, namely to exploit the elongational flow field at the entrance to a capillary and alternatively to make cast films of a water soluble polymer containing the colloidal particles and draw them in the solid state. In the latter method, sections of film were elongated at an elevated temperature using a tensile testing machine. The drawn films were dissolved in water and the deformed particles were extracted and concentrated by ultracentrifugation. This method was successful in producing ellipsoids of a prescribed aspect ratio. Further successful deformation was carried out using PMMA particles and monodisperse polystyrene particles. Polystyrene spheres containing 20 nm diameter magnetite particles could not be deformed using this process. A range of experimental techniques were exploited to characterise the ellipsoidal particles, including transmission electron microscopy and photocorrelation spectroscopy. Subsequent addition of metal oxide particles to the polymer ellipsoids resulted in some success in that a small number of 20 nm diameter magnetite particles was observed to be attached to the surfaces of the much larger (1 μm) polystyrene ellipsoids. The mechanism of attachment has not yet been elucidated but this has significant potential for future composite device production.

Policy instruments for sustainable land management: the case of highland smallholders in Ethiopia

AbstractDegradation of land continues to pose a threat to future food production potential in many developing economies. Various approaches, mainly based on command‐and‐control policies, have been tried (with limited success) in the past to encourage adoption of erosion‐control practices by farm households. High transactions costs and negative distributional impacts on the welfare of the poor limit the usefulness of standards and taxes for soil and water conservation. One innovative approach is the use of interlinked contracts which create positive incentives for land conservation. This study analyses the social efficiency of such policies for erosion‐control in the Ethiopian highlands using a non‐separable farm household model. Incentive contracts linked with conservation seem to be promising approaches for sustainable resource use in poor rural economies. This may suggest that conservation programs should give greater consideration to better fine‐tuning and mix of policies that help achieve both economic and environmental objectives.

Abstract: Future Petroleum Production from Indonesia and Papua New Guinea

Deep water systems and natural gas are two sectors that will likely show significant production growth within the next decade in Indonesia and Papua New Guinea. At least six deep water areas are poised for further petroleum exploration, and a number of large gas projects are awaiting development. Frontier exploration, innovative enhanced recovery techniques, production from gas hydrates, and use of gas-to-liquids technology could unlock additional large petroleum volumes for exploitation in the region over the longer term. More than 55 billion BOE of ultimate reserves have been discovered to date in the two countries, reservoired in about 1,000 fields within >50 separate proven petroleum systems. Of this total, at least 12.5 billion BOE (75 TCF) of discovered gas reserves await development offshore Natuna Island, onshore and offshore Irian Jaya, and in the Fold and Thrust Belt of Papua New Guinea. Planned infrastructure to exploit these resources, such as the proposed international gas-export pipeline from Papua New Guinea to Queensland, will spur future activity in these relatively high cost and remote areas. Significant increases in activity and production potential can also be expected in offshore deepwater areas, such as the Makassar Straits in Indonesia, where recent oil and gas discoveries have been made in water depths approaching 1,000 meters. In addition to proven petroleum systems, at least 50 lightly explored to unexplored speculative petroleum systems exist, both onshore and offshore, with the highest potential for future production likely from frontier areas in Eastern Indonesia and Papua New Guinea.

A South African national economic and environmental policyframework1

Most contemporary economic theories upon which conventional national accounting is based regard man‐made assets as productive capital to be depreciated against the value of production. Such production, without replenishment or renewal of the asset or capital stock, is not sustainable. Natural resource assets, however, are not valued in the same way. There is no accounting mechanism to reflect the decrease in potential future pro duction as the resource diminishes or deteriorates. In 1993, the United Nations adopted its guidelines for a ‘System of Integrated Environmental and Economic Accounting’ (SEEA), which allows for the adjustment of the System of National Accounts (SNA) for natural asset stripping and degradation, providing a format for national accounting which assesses the viability and sustainability of economic growth. The concept of an SEEA for South Africa was pursued in 1994 as a pilot study. The framework to be devel oped was termed the South African National Economic Environmental Planning (SANEEP) model. The framework can be used to predict the environmental impact, in terms of natural resource use and degradation, of economic growth, both nationally and at the sectoral level. In addition, it can be used to test the sectoral economic impact, and thus the desirability of certain types of environmental economic instruments such as pol lution taxes, or the imposition of royalties on mineral extraction. Hence, the SANEEP framework has the potential to become a broad‐based, integrated environmental and economic planning tool. This article describes the SANEEP model, its information requirements and applications.

World agricultural futures: regional sustainability and ecological limits

There is a wide spectrum of views on possible futures for world agriculture, with a clear division between neoclassical and ecological economics approaches to the issue. An incremental approach, characteristic of neoclassical economics, focuses on steady yield increases as a result of technological progress and increased input use. In this view, there are no inherent limits to growth and therefore an optimistic view tends to be taken of future production potential. By contrast, an analysis based on the concept of carrying capacity emphasizes environmental limits to system growth. This paper reviews estimates of carrying capacity as well as trends in land use, yields, and environmental impacts of agriculture. Demand projections are made for the year 2025 based on population momentum and a slow rate of increase in per-capita consumption. The global system is seen to be approaching carrying capacity limits over the next 30 years, with more severe stresses at a regional level, and widening food deficits in developing nations. Strong yield growth in China, South Asia, Africa, North America, and Europe will be necessary to avert global shortfalls, but resource and environmental factors pose serious constraints in all these areas. The pressure to increase yields is therefore in conflict with the requirements of long-term sustainability. This indicates the need for regional models of sustainable agro-ecosystems which balance yield requirements with ecological constraints. In addition, demand-side issues of population policy, efficiency in consumption, and distributional equity become increasingly important in a world of constrained agricultural growth.