bluuebunny/crossref_metadata_2025 huggingface dataset:
CO2 Injection and Storage: A New Approach Using Integrated Asset Modeling
Authors: Primera A. , Sifuentes W. , Rodríguez N.
Published: June 2009

The reduction of greenhouse gas emissions in order to decelerate the global warming process could be achieved through the emerging process of geological CO2 storage. Also in terms of Enhanced Oil Recovery (EOR) the injection of CO2 as a pure component or as part of a mixture has proved to increase the productivity of oil and gas reservoirs.

Optimization techniques have been applied independently to the reservoir and surface models, leading to non-optimal solutions due to the non-dynamic integration between models. A recent trend of the industry is the integration of sub-surface and surface simulators to have a better representation of the fluid production/injection, taking into account the constantly changing interaction between systems.

The integrated approach has been used to integrate multiple reservoirs with common and advanced surface facilities to properly model the fluid flow behavior of the asset. Different injection variables, facilities, well completion, number of wells have been included in the analysis and numerical reservoir simulation models have been integrated with a network. As CO2 is captured, it is transported and re-injected to neighbor reservoirs, as an enhancement process for productivity or for storage purpose.

After proving the feasibility of facilities for CO2 injection as EOR process or storage, the integrated approach has shown a more comprehensive solution that could be used for the design and further optimization of this type of projects. Analysis of reservoir properties as permeability, temperature, etc. is also taken into account in order to asses the viability of the CO2 optimal injection and storage strategy, while minimizing cost. Finally, integrated asset modeling also shows the flexibility to represent different types of settings such as CO2 source (reservoir and/or fossil fuel power plants), types of reservoirs and network scenarios.
Reservoir Management Challenges and Improved Hydrocarbon Recovery Activities on Kvitebjørn HPHT Gas Condensate Reservoir
Authors: Talukdar Saifullah , Rasmussen Janikke , Wennberg Kjell Erik , Lien Linda Storetvedt
Published: June 2009

The Kvitebjørn medium rich gas condensate field in the Norwegian North Sea is characterized as a high pressure high temperature (HPHT) reservoir with 770.5 bar pressure and 150°C temperature at about 4000 m TVD MSL. Despite high temperature and depth, the average reservoir properties are reasonably good. The main reservoir is Brent Group of Middle Jurassic age which is extensively faulted.

One of the main challenges is the drilling in depleted reservoir. The strategy to mitigate the problem has been to put the field on reduced production and/or to actively manage reservoir pressure by producing more from areas far away from the drilling locations. Advanced drilling technologies have also been developed to improve drillability.

Several improved oil/gas recovery methods are currently under consideration, which include infill drilling, process capacity upgrading, low pressure-production and gas recycling. Infill drilling is challenging due to reservoir depletion. Capacity upgrading is to be implemented to expedite hydrocarbon recovery. Gas recycling has some potential for improved condensate recovery, but the project economy is poor. Low pressure production appears to be a very attractive option. A compressor concept has been selected based on thorough evaluation of space and weight limitations on the platform, possibility for future drilling and intervention operations, explosion hazard, tie-in of other prospects and future export facilities etc. Subsurface challenges include uncertainties related to well integrity and productivity, reservoir communication, reservoir volumes, etc.

The purpose of this paper is to present the challenges related to development and management of this HPHT gas condensate reservoir, the strategies to overcome the challenges and the methods to improve gas and condensate recoveries from this field with special focus on the low pressure production and gas recycling.
Improving Reservoir Simulation Models Using 4D Data at the Snorre Field
Authors: Seldal Mailin , Reime Arild , Arnesen Dag
Published: June 2009

New reservoir simulation models have recently been established for the Snorre field based on updated geological models and fully revised input data. The Snorre reservoir is highly heterogeneous, comprising stratified and heavily faulted fluvial deposits. The field is pressure supported by water alternating gas (WAG) injection, resulting in complex drainage patterns.

Time-lapse seismic is amongst the technologies applied to improve reservoir understanding and has provided valuable information on fluid front movement and fault communication.

The paper describes a first systematic effort on honouring 4D data in the Snorre reservoir simulation models. A workflow converting 4D responses into 3D volumes in the reservoir modelling software for easy comparison to simulated reservoir performance proved very useful in the multidisciplinary work process. The models are history matched with respect to pressures, production rates and fluid front movement from tracer and 4D data. Though the seismic time-lapse responses are matched qualitatively, they have improved the overall Snorre reservoir understanding.

Different applications of 4D data in the history matching process are discussed, e.g. determining fault transmissibilities and water front movement, identifying water producing intervals and re-allocation of zonal contributions in wells. A successful water shut-off based on 4D interpretations and simulated future performance is also discussed.
Fluid Pressure Gradients in Tight Formations
Authors: Larsen J. A. , Urkedal H. , Lønøy A.
Published: June 2009

Low-permeable reservoirs have long been recognized as a challenge for economical production. Characterization of complex carbonate reservoirs exhibits some special challenges. Pay zones may be poorly defined due to marginal reservoir properties, i.e., uncertainties regarding the distribution of oil on the pore scale and the ability of oil to flow at high initial water saturation. Hence, the oil water contact may not be a precise level in the reservoir and the vertical span of the oil-water transition zone may be greater than 100 meters in such reservoirs. The traditional reservoir engineering approach defines free water level and hence the water- and oil-zones from the oil- and water pressure gradients. Pressure gradients are, however, difficult to obtain in low-permeable media and it has been reported that supercharging effects may be the result of mobile oil and water at the same place in the reservoir.

A case study is made for an offshore exploration well in a complex and heterogeneous carbonate oil reservoir. The well is not production tested and gives a clear water gradient. However, there is indication of relatively high oil saturation with possible live oil properties. This is not typical for a reservoir that has been completely water washed during historical time.

Different initial fluid distributions are studied in simulation of filtrate invasion in order to explain the observations in the exploration well. The results are of general interest, with application to many low-permeable reservoirs. This work gives new insight into the important interplay between type of drilling mud, reservoir wettability and interpretation of fluid gradients. The novel implication of the results is that a water-gradient is measured in the transition zone if an oil-wet reservoir is drilled with water-based mud. A water gradient can therefore exist even though the oil saturation is high. The shift between the water gradient and oil gradient occurs when mobile oil is present in water-wet pores giving a positive oil-water capillary pressure.
Opportunities for Geothermal Energy in Franekeradeel, Netherlands
Authors: Heijnen L. J. , Buik N. A. , Willemsen A. , Bakker T. , Diephuis G.
Published: June 2009

The potential for the exploration and exploitation of geothermal energy for greenhouses in Franekeradeel in the north of the Netherlands has been investigated. Available borehole and seismic data have been used for the evaluation of the subsurface. These data show that the Slochteren Formation sandstone reservoirs are very likely present at a depth of ca 3,000 m. These reservoirs are deemed to be suitable for the production of hot water. From interpreted 2D seismic lines could be inferred that the Slochteren Formation is around 200 m thick at the proposed location. Based on the local geothermal gradient, the temperature at the top is estimated to be around 100 °C. At the surface location a fault zone is present in the subsurface complicating the siting of the injection and production wells. Towards the northeast the proposed reservoir is seemingly less faulted. A minimum transmissivity of 11 Dm is expected, based on the measured porosity in nearby boreholes and porosity-permeability relationships in the surrounding area. A potential flow rate of 160 m3/h is hence inferred, leading to a thermal capacity of 11 MWt which can be delivered with one doublet. Different well configurations were studied. The conclusion is that deviated wells from the edge of the surface location towards the northeast carry the lowest risk at still acceptable costs. From financial analyses taking different options into account, it was concluded that geothermal energy can deliver significant amounts of renewable energy for heating of greenhouses. In the optimum situation, the cost price of heat amounts to 6,20 Euro/GJ delivering annual 202 TJ of energy. This price is below the current price (January 2008) of natural gas at 0,20 Euro/m3.
Uncertainty Evaluation in Field Development and Export Planning
Authors: Akeze Azuka Christian , Sikandar Ali Shahbaz , LaForce Tara
Published: June 2009

Decision making in the face of uncertainty is a problem encountered at every strategic level within the exploration and production value chain. This problem is evident in new field development projects when there is limited and uncertain geologic and engineering data. Key uncertainties encountered in reservoir engineering models include drive mechanism, permeability, aquifer support, fluid properties, reservoir extent and connectivity, end point saturations and reservoir structure. Evaluating uncertainty using conventional methods, where model parameters are varied individually, makes it impossible to make an objective business decision without underestimating the effects of uncertainty.

This work proposes a systematic approach to evaluate uncertainty in a field development decision process. Initially parameters are varied individually to rank the key uncertainties. Subsequently the experimental design approach is used and a response surface is developed to estimate the impact of uncertainty in the parameters with the largest influence on project economics. In order to integrate the uncertainty in availability of surface facilities, project economics and sub-surface properties, a decision tree is designed to incorporate risk into a logical and consistent decision strategy. Information analysis is also performed to estimate the value of acquiring additional information.

The proposed decision-tree is applied to development planning of a field comprising of marginal stacked reservoirs. Numerical simulations are performed to optimize the field development and generate a range of oil recovery predictions. The surface facilities options, project economics and predicted recoveries were then integrated into the decision tree. The value of the project was positive for most outcomes, with negative value occurring only for the lowest oil recovery combined with delayed access to surface facilities. The economic value of obtaining additional information was much lower than its cost.
Rapid Evaluation of Geological and Reservoir Uncertainty in a Multi-Field Development
Authors: Edwards Glyn , Sadikoglu Kasim
Published: June 2009

An automated modelling process for rapidly evaluating differing multi-field development production strategies under geological uncertainty has been developed. We demonstrate the use of the technique on the Charlie, Alpha, and Bravo (CAB) fields lying in deepwater, offshore Angola. The names of the fields have been changed to preserve confidential data.

CAB is a planned clustered development with all CAB reservoirs producing back into a single Floating Production Storage and Offloading (FPSO) vessel. Due to a challenging seismic environment causing considerable geological uncertainty, stochastic modelling was used to populate reservoir models bounded by seismically interpreted deterministic channel system surfaces. The CAB team developed a systematic modelling workflow combining static and dynamic data for simulation using a multi-field reservoir simulator. Evaluating each new geological model was a manual process taking up to 10 days.

To accelerate the modelling process, the entire workflow was automated and BP's Top-Down Reservoir Modelling (TDRM™) philosophy and toolkit (Williams et al., 2004) was used to investigate the affect on hydrocarbon recovery of different possible geological models. Automation involved generating stochastic geological realisations for each CAB field and simulating simultaneous production from all three fields with reinjection of the produced gas. Up to 30 different multi-field simulations could be generated and simulated every 24 hours, with the workflow using 10 CPUs

Approximately 700 multi-reservoir simulation runs (2100 individual reservoir simulations) were conducted within a two month period. By automating the workflow, more time was available for evaluating simulation results and less time was spent preparing data and running the simulations. The automated workflow has been used to decide FPSO capacities and to gain confidence that the Charlie field could take all produced gas without flaring or significant loss of production. The workflow continues to be used to quantify the effects of geological uncertainty on different gas management strategies.
SAGD Subcool Control with Smart Injection Wells
Authors: Gotawala Dharmesh R. , Gates D.
Published: June 2009

Steam-Assisted Gravity Drainage (SAGD) is a widely used in situ recovery process for heavy oil and bitumen reservoirs. The performance of the SAGD process is tied with growth of the steam chamber which in turn depends on uniform steam delivery along well length and the underlying geology and fluid properties in the near wellbore region. If the reservoir has poor injectivity due to poor underlying geology oil production suffers. This can be avoided in by examining the interwell subcool. The subcool is the temperature difference between the injected steam and produced fluids. In this study, Proportional-Integral-Derivative (PID) feedback control has been employed to control inflow control valves settings to promote subcool to a target value. This control strategy is examined by using a PID algorithm to control SAGD in a detailed three-dimensional heterogeneous reservoir model with properties typical of an Athabasca bitumen reservoir. Specifically, the SAGD injector is divided into six intervals each with its own steam injection pressure. The interwell subcool is calculated and the PID feedback control algorithm is used to direct the subcool to a target value by changing the steam injection pressure in each well interval. The results show that this control method can be used to enhance uniform steam chamber growth and ultimately more oil production with less steam injection. The key benefit of dynamic well control is that the injection strategy is adjusted dynamically to fit the underlying geological and fluid compositional heterogeneity to obtain improved steam conformance along the wellpair. This implies that potentially a priori detailed knowledge of the geological and fluid compositional heterogeneity may not be as critical for well placement for uniform steam conformance.
Potential for Hydrogen Generation during In Situ Combustion of Bitumen
Authors: Kapadia Punitkumar R. , Kallos Michael S. , Leskiw Chris , Gates Ian D.
Published: June 2009

The volume of heavy oil and bitumen in Alberta, Canada is estimated to be about 1.7 trillion barrels. The majority of the produced heavy oil and bitumen in Alberta is converted in surface upgraders to synthetic crude oil, a crude oil with API gravity typically between 31 and 33°API, which in turn can be converted to fuel, lubricant, and petrochemical products in standard refineries. To upgrade bitumen requires hydrogen. In current practice, much of this hydrogen is generated from steam reforming of methane together with the water-gas shift reaction. This means that heavy oil and bitumen upgrading, as is currently done, requires huge amounts of natural gas to generate hydrogen. The potential for in situ generation of hydrogen by gasification of bitumen reservoirs offers an attractive alternative which can also have both economic and environmental benefits. For example, hydrogen generated from bitumen gasification can also be used for in situ upgrading as well as feedstock for ammonia and other chemicals. The water-gas shift reaction also generates carbon dioxide which could be potentially sequestered in an in situ gasification process so that emissions to the atmosphere are reduced. This study evaluates the effect of operating parameters such as temperature and pressure on the amount of hydrogen generated during in-situ combustion. Combustion of Athabasca bitumen incorporating thermal cracking, oxidation, and hydrogen generation and consumption reactions has been simulated. The results indicate ranges of temperature and pressure where bitumen combustion yields optimal hydrogen production. This research emphasizes the conditions at which hydrogen production can be maximized from the in-situ combustion of Athabasca bitumen. This technology provides a potentially clean method to produce fuel and feedstock material from bitumen, a relatively "dirty" fuel and feedstock oil, in addition to more energy efficient ways of extracting in-situ heavy oils.
Assisted Procedures for Definition of Production Strategy and Economic Evaluation Using Proxy Models
Authors: Avansi G. D. , Schiozer D. J. , Suslick S. B. , Risso F. V. A.
Published: June 2009

New techniques for reservoir development are essential for dealing with the complexities of geological models. In this sense, numerical simulation is the tool used to define the quality of a production strategy. However, the process to define variables such as well numbers, completion layer, open timeline and operational conditions demand several simulations due to the high time consumption and computational effort. Sub-optimal results can be obtained from manual processes. Automatic processes can mitigate this problem but the computational effort is increased as a result of the number of simulations generated in the process.

In order to minimize this problem, this paper proposes an assisted procedure for its automatic part using proxy models to accelerate the process. Furthermore, due to the reduced time to evaluate options, it allows a better evaluation of the solution space using better optimization techniques. Proxies have been used in important applications such as risk analysis and history matching but the use for definition of production strategy is not common.

The proposed methodology involves the following components: statistical methods, experimental planning to generate the response surface methodology for the generation of proxies and consistency checking.

The results show that it is possible to apply proxy models for this type of problem and they can identify the best production strategies, reducing the computational effort during the process. The suggested procedure is to use proxies in the automatic part of the assisted procedure used in the optimization process.

The main contribution of this work was the demonstration that proxy models can be used for the definition of production strategies, bringing an additional option to the decision analysis process linked with petroleum field development.
A Cost Effective and User Friendly Approach for Mini-DSTs Design
Authors: Bertolini C. , Tripaldi G. , Manassero E. , Beretta E. , Viberti D. , Verga F.
Published: June 2009

mini-DSTs are gaining more and more popularity as a possible alternative to conventional well testing especially where there are major environmental and economical constraints. The increased offshore exploration activity, which often implies highly risky and huge operational costs, makes the conventional well testing less attractive in favor of other technologies that can provide some of the key dynamic information about the well-reservoir system through relatively quick and less expensive operations. The design phase is recognized to be one of the most critical aspects in order to guarantee an acceptable value of information in exploration scenarios where very limited data is available. The success of any mini-DST operation can be significantly compromised if two major issues are not addressed in the design phase: possibility to clearly identify the radial flow behaviour, and avoidance of noise in the pressure response due to the gauge resolution.

The paper describes a new user-friendly approach for mini-DST design, which allows one to easily identify whether this technology can be successfully applied. The approach is based on the use of dimensionless and dimensional charts, which are of general validity because they can be applied to any lithological environment and for any type of hydrocarbon. Field applications proved the charts to be very powerful because they could predict the range of effectiveness of mini-DST's.
Negotiating trade-offs in water resources development in the Mekong Basin: implications for fisheries and fishery-based livelihoods
Authors: Friend Richard M. , Blake David J. H.
Published: June 2009

A revitalised hydropower development narrative is emerging in the Mekong in which the concept of ‘trade-offs’ plays a central role. The importance of and risks to capture fisheries in the Mekong is such that any degradation has huge social, economic and environmental implications. While potential impacts of hydropower development on capture fisheries are acknowledged in this emerging narrative, it is argued that these are less than anticipated previously, that impacts can be assessed, mitigation measures introduced and trade-offs negotiated. The concept of trade-offs has an immediate appeal but it is also problematic. It draws attention away from considering development objectives and options towards focusing on impacts, and infers a technical approach as opposed to a political process of decision making. This paper draws on anthropological approaches to development policy to consider the implications of a hydropower narrative based on trade-offs in light of experience in the Mekong Basin, and to consider alternative ways of framing debate on hydropower and capture fisheries.
Economics and livelihoods of small-scale inland fisheries in the Lower Mekong Basin: a survey of three communities in Cambodia
Authors: Navy Hap , Bhattarai Madhusudan
Published: June 2009

This paper presents economic analysis, viability and trade-off issues for small-scale (family) inland capture fisheries in three fishing communities, each representing a distinct floodplain characteristic in Cambodia. The average net profits of family fishing was US$12 and US$4.6 per trip during the open (October to May) and close (June to September) seasons, respectively; but real profit—deducting the cost for family labour from net profit—was only US$4.5 and US$1.6 during the open and close seasons, respectively. The return from family fishing varied greatly across sites surveyed, depending on the quality of the fishing grounds, hydro-ecology settings, local institutions, and socio-economic factors. The high degree of seasonality, the spatial variation of returns and costs of capture fisheries suggest interdependence of fishing activities with basin-level water allocation policies, and also related trade-off in the fisheries sector with water allocation and water resources management policies. There is also now an urgent need for synergy of the various rural development efforts with that of fisheries policies in the Mekong River Basin.
A comparative study of two seasonal floodplain aquaculture systems in Bangladesh
Authors: Mustafa M. G. , Brooks Alan C.
Published: June 2009

This paper presents a comparative analysis of the technical and economic parameters of two community led approaches: the semi-closed water bodies and the floodplain water bodies based systems in Bangladesh. The two approaches differ in management, fish production, impact on biodiversity, capital investment and annual variable costs, share of profits and proportional benefits for the poor, and impact on allied businesses—the so-called backward and forward linkages. For the semi-closed water bodies (beels) the fish harvest increased from an annual average of 380 kg ha−1 in 2002 to 921 kg ha−1 by 2005. During the same period, the biodiversity measured for self-recruiting indigenous species, using the Shannon-Weiner Index (H′), increased significantly (P<0.05) from 2.24 in 2002 to 2.56 in 2005. For the floodplain aquaculture system (Pankowri or Daudkandi model) annual fish production ranged from 1.5 to 1.8 t ha−1. Annual net economic benefit per hectare was found to be Taka 37,710±24,600 and 26,819±10,780 for semi-closed and floodplain systems respectively. The net income per kg of product was found to be Taka 44.0±9.0 and 13.0±3.0 for semi-closed and floodplain systems, respectively. The floodplain system tends to use comparatively more feed and fertilizers per unit area that pond-based aquaculture.
Cross-scale trade-offs and synergies in aquaculture, water quality and environment: research issues and policy implications
Authors: Gichuki Francis N. , Kodituwakku Dekshika C. , Nguyen-Khoa Sophie , Hoanh Chu Thai
Published: June 2009

This paper sets the stage for this Special Issue covering a set of papers, which try to provide a cross-scale evaluation of the trade-offs and synergies evident among aquaculture, water quality and environment in the empirical context of 8 different countries from Asia and Africa. Having discussed the livelihood and policy significance of the issue of cross-scale trade-offs and synergies, this paper provides an eclectic review of literature to show how this issue has been insufficiently treated in past studies. With a brief overview and synthesis of the papers included in this Issue, this paper also indicates how they overcome the analytical, methodological, and data challenges so as to provide a cross-scale evaluation of the trade-offs and synergies in different empirical settings. After illustrating how the new research insights can be integrated into the public debates and policy processes, this paper concludes with the identification of future research and policy needs.
Facilitating dialogue between aquaculture and agriculture: lessons from role-playing games with farmers in the Mekong Delta, Vietnam
Authors: Dung L. C. , Hoanh C. T. , Le Page C. , Bousquet F. , Gajaseni N.
Published: June 2009

During the last few years, conflicts between agriculture and aquaculture have been an important issue in the Bac Lieu province, Mekong Delta, Vietnam. A large area of rice production has been converted to shrimp or shrimp–rice based production systems that require the intake of saline water into fresh water zones that have been used for agriculture. To manage this conflict, the provincial authorities have reviewed land use plans and identified a buffer zone with a mixed land use system of shrimp–rice (rice in the rainy season and shrimp in the dry season when sluices are opened). Under the CPWF (Challenge Program on Water and Food) Project No. 25, role playing games (RPGs) were applied for analyzing the land and water management strategy of farmers in the buffer zone. The RPGs organized in three villages (Phong Thanh, Ninh Thanh Loi and Vinh Loc) indicate that due to much higher revenue earned from shrimp compared with rice, farmers are attempting numerous techniques to prolong the duration of saline water in their fields for shrimp cultivation. This strategy makes the growing of a subsequent rice crop impossible even in the rainy season, thus requiring harmonization of water management at different levels (farm and canal systems). The results from these RPGs also indicate the need for further research on cultivation techniques for the shrimp–rice systems and on participatory methods to achieve better understanding of farmers' decisions.
Hydraulic and water quality modeling: a tool for managing land use conflicts in inland coastal zones
Authors: Hoanh C. T. , Phong N. D. , Gowing J. W. , Tuong T. P. , Ngoc N. V. , Hien N. X.
Published: June 2009

Tidal effect and salinity intrusion are two defining characteristics of inland coastal zones, causing, respectively, complex variations in water levels and flows in river and canal networks, and serious problems for agriculture and freshwater fishery, but bringing significant benefits for brackish water aquaculture. To evaluate these conflicts and synergies in the development of agriculture, fishery and aquaculture, this paper adopts a hydraulic and salinity modeling approach that simulates the tidal propagation and salinity intrusion, and evaluates the effects of water and land use management on these hydrology- and salinity-related phenomena in coastal zones. The paper presents the empirical results from the application of a hydraulic and salinity model specifically developed for the context of the Ca Mau peninsula, Mekong Delta, Vietnam, and also demonstrates how such a modeling approach can provide valuable policy-relevant information at different phases for water resource planning, development, operation, and management in hydrologically and environmentally sensitive coastal regions.
Modeling water supply and demand scenarios: the Godavari–Krishna inter-basin transfer, India
Authors: Bharati L. , Smakhtin V. U. , Anand B. K.
Published: June 2009

The Government of India's National River-Linking Plan (NRLP) aims to alleviate emerging water scarcity problems by transferring water from well endowed to more deficient areas. This study evaluated the plausible future scenarios of water availability and use under conditions of various cropping patterns, and with the explicit inclusion (for the first time) of environmental water requirements for one of the links of the NRLP: from the Godavari River at Polavaram to the Krishna River at Vijayawada—the ‘Polavaram Project’. The scenarios were evaluated using the WEAP (Water Evaluation and Planning) model. The study generates information for use in managing emerging trade-offs. The importance of explicit accounting for monthly variability in description of water supply and demand, in the monsoon-driven climate conditions of the region, is advocated. Such detailed scenario simulations and inclusion of previously unaccounted for factors/uses can help to create awareness of potential future problems, inform water management practices and suggest management alternatives. Results show that the proposed water storage and transfer will reduce water deficit within the project command area and significantly reduce dry slow river flow into the Lower Godavari Delta.
Comparison of Aerosol Optical Depth (AOD) Derived from Ground-Based LIDAR and MODIS
Authors: Chan P.W.
Published: June 2009

The performance and application of AOD products from the Moderate Resolution Imaging Spectroradiometer (MODIS) are studied by comparing with the AOD derived from the ground-based Doppler LIDAR inside the Hong Kong International Airport (HKIA). The backscattered power data of the LIDAR are used to determine the extinction coefficient profile, from which the AOD is calculated. The AOD determined from the LIDAR is found to have good quality by comparing with the AOD measurements from a hand-held sun photometer at HKIA over a period of three months, and as
such it is used to study the quality of AOD estimated from MODIS. The 1-km resolution AOD product from MODIS is found to have better correlation with the LIDAR AOD in comparison to the 10-km resolution product. Moreover, since AOD is a column-integrated quantity, its application to the monitoring of the surface visibility changes should be made with caution during the presence of elevated layers of higher aerosol concentrations. Examples of the effects of such elevated aerosol layers are studied.
TGF Presence During IgE-dependent Sensitization Primes Mast Cells for Higher VEGF Production After Fc RI Activation
Authors: Pablo Benitez-Garrido Juan , Ibarra-Sanchez Alfredo , Macías Silva Marina , Villalobos Molina Rafael , Alejandro Padilla-Trejo Jose , Gonzalez-Espinosa Claudia
Published: June 2009

Binding of monomeric Immunoglobulin E (IgE) to the high affinity IgE receptor (FcεRI) on mast cells induces a sensitization process which increases cell survival, augments membrane receptor expression and diminishes activation threshold. Although IgE-dependent sensitization is fundamental for allergic reactions, little is known about the influence of locally produced mediators on the outcome of a posterior allergen challenge. Since Transforming Growth Factorβ (TGFβ) is an important immunomodulator present in most of the tissues where mast cells reside, we decided to analyze the consequences of TGFβ exposure during the sensitization step of mast cells on a posterior IgE-antigen stimulation. Bone Marrow-derived Mast Cells (BMMCs) were sensitized with IgE in the presence or absence of TGFβ. Then, antigen was added and the secretion of the angiogenic cytokine Vascular Endothelial Growth Factor (VEGF) was determined. BMMCs sensitized with IgE+TGFβ showed an increased antigen-induced VEGF secretion compared to those sensitized with IgE alone. Sensitization with IgE+TGFβ did not modify membrane FcεRI receptor expression neither altered antigen-induced degranulation of the cells. Although both IgE and IgE+TGFβ sensitized cells showed an increase in VEGF mRNA stabilization after antigen addition, VEGF mRNA half-life was longer in IgE+TGFβ sensitized cells. p38 MAPK inhibitor SB202196 blocked VEGF mRNA stabilization after antigen addition specially on IgE+TGFβ sensitized cells. These findings suggest that TGFβ presence during the sensitization phase of mast cells can induce modifications to the FcεRI signal transduction system, provoking increased VEGF mRNA stabilization and protein secretion after IgE-antigen stimulation through a p38 MAPK-dependent mechanism.
Mathematics Education in the Early Years: Building Bridges
Authors: Anthony Glenda , Walshaw Margaret
Published: June 2009

Aligned with the enhanced international commitment to early childhood education, recognition of the importance of providing young children with opportunities to develop mathematical understandings and skills is increasing. While there is much research about effective mathematics pedagogy in the school sector, less research activity is evident within the early childhood sector. Focused on people, relationships and the learning environment, this article draws on a synthesis of research on effective pedagogical practices to describe effective learning communities that can enhance the development of young children's mathematical identities and competencies. Concerned that the wider synthesis noted limited cross-sector collaboration within the mathematics education community, this article aims to act as a bridge for researchers currently working within the preschool and school sectors. The authors argue that understandings of effective pedagogies that enhance young children's mathematics learning will benefit from more cross-sector research studies.
The Parent—Teacher Conference in the Swedish Preschool: A Study of an Ongoing Process as a ‘Pocket of Local Order’
Authors: Markström Ann-Marie
Published: June 2009

This article explores the construction of parent—teacher conferences in the Swedish preschool and focuses on processes that construct and maintain these meetings. The analysis draws upon an ethnographic study in two preschools and the empirical material consists of 11 audiotaped parent—teacher conferences and observations of everyday activities related to them. By using empirical data from a wider context than the specific speech event, it is possible to gain knowledge about the complexity of the construction of parent—teacher conferences. Using the concept of a ‘pocket of local order’, it is argued that parent—teacher conferences are practices which consist of a large number of activities linked to resources and restrictions that can be interpreted as an imperative to the participants to conduct talks in preschool and at home, to fill in forms and then use these activities in the conference. In addition, parents and teachers, as well as children, contribute to the construction and maintenance of the pocket of local order, i.e. activities that can be interpreted as an imperative to the actors to reach institutional goals.
Relationship Theory in the Nursery: Attachment and beyond
Authors: Degotardi Sheila , Pearson Emma
Published: June 2009

Contemporary approaches to early childhood education widely acknowledge that young children's relationships with others play a fundamental role in their learning and development. This article explores the construct of relationships within the context of early childhood infant programmes through an examination of the contribution and applicability of attachment theory to current understandings of the nature and consequences of young children's relationships in these settings. A review of the sociocultural context of relationships, the infants' role in relationship formation, and the nature of peer relationships leads to the proposal that practitioners, policy makers, and researchers need to adopt a wider, more dynamic approach to relationships that includes, but extends beyond, that afforded by attachment theory alone.
Shaping Conduct and Bridling Passions: Governing Practicum Supervisors' Practice of Assessment
Authors: Ortlipp Michelle
Published: June 2009

Courses preparing early childhood professionals through institutes of technical and further education utilise competency standards to guide the assessment of students during professional experience. Some universities offering early childhood teacher education courses use the term ‘competencies' in practicum assessment forms and draw on teacher competency standards. This article explores how discourses of competence produced within positivist and liberal humanist discourses shape, guide and direct (govern) tertiary supervisors' beliefs about and understandings of the legitimacy of their professional judgement. Tertiary supervisors take up these discourses and use them as the basis upon which they govern themselves. The author argues that one of the effects of governmentality in this instance is that tertiary supervisors regulate and silence their professional judgement and defer to discourses of scientific rationality when assessing students on practicum placements. They produce assessment strategies that enable them to hide their subjective judgement within what appears to be a logical, rational and objective assessment process and position themselves as the rational, objective assessor, and, at the same time, the fair, responsible tertiary supervisor.
‘Crossing the Rubicon’: Strategic Planning or Neo-Biopower? A Critique of the Language of New Zealand's Early Childhood Strategic Plan
Authors: Stuart Margaret
Published: June 2009

‘Strategy’ is a word that has had an increasing use in recent years. The discipline of organisational studies has adopted this concept to set out the primacy of good business practices, such as foretelling risk and opportunity. Government policy documents use the term where medium- and long-term goals are set out, for example, the New Zealand Ministry of Education's Pathways to the Future. A Ten-Year Strategic Plan for Early Childhood Education. This article uses Michel Foucault's methodology of genealogy to trace the emergence of the term ‘strategy’, its use in organisational studies, and its displacement to education, specifically early childhood education in Aotearoa/New Zealand. The study by Richard Whipp into the effectiveness of strategic planning supports the problematising of the term. The study deconstructs some naturalised truths about the image of people, of time, and of analysts' reflexivity. It asks about the use of terms that originated in the military lexicon, such as ‘manoeuvres’, ‘strategy’, ‘target’, ‘plan’ and ‘risk’, but have slipped to that of business practices, retaining traces, however, of the original military intent. Foucault inverted the phrase that ‘politics is war by any other means' as institutions centralised control, set up supervision of populations, and collected statistics to plot changed patterns. This article examines some of the tracery that remains in such use of governmental language, and asks if this is the most appropriate lexicon for education.
The Lives of Sesame Street: The Impact of Foreclosures on Young Children and Families
Authors: Davis Danné E. , Shin Minsun
Published: June 2009

While significant attention has been paid to Wall Street investors and families impacted by the current subprime mortgage crisis in the USA, the lives of Sesame Street are minimally discussed. Children and their families are enduring a variety of consequences of foreclosures. The consequences can be hugely disruptive to the approximately 2 million voiceless victims. For the youngest citizens of the USA — its children — the subprime mortgage crisis, particularly home foreclosures, is impacting school attendance, academic performance and achievement, social development and emotional well-being. The authors argue that media and political attention should also include the unintended and often unnoticed repercussions of foreclosures on young children and their education. It is also argued that educators and policy makers should create policies and develop concerted efforts to alleviate the negative impacts on young children.
Children's Expressions of Exhilaration and Fear in Risky Play
Authors: Sandseter Ellen Beate Hansen
Published: June 2009

Children naturally seek and conduct exciting forms of play that involve a risk of physical injury (risky play). Even though several prior studies give descriptions of risky play, none of them deeply explore children's expressions of how they experience different kinds of risky play. This study aims to do that. The results from video observations of children's risky play in two Norwegian preschools reveal that children experience several emotions, expressed bodily, facially, and verbally, while engaging in risky play. Their experiences include both pure exhilaration and pure fear, and quite often both emotions are present at the same time. The findings also indicate that one of the main aspects of risky play is to keep the exhilaration bordering on the feeling of pure fear; but if pure fear occurs, the play ends with withdrawal. Suggested implications of the study are that risk taking should be acknowledged as an important part of children's play, and that children should be able to engage in challenging play adjusted to their individual sense of risk and urge for exhilaration.
Presurgical identification of the primary sensorimotor cortex by functional magnetic resonance imaging
Authors: Pujol Jesús , Conesa Gerardo , Deus Joan , Vendrell Pere , Isamat Fabián , Zannoli Guillermo , Martí-Vilalta Josep L. , Capdevila Antoni
Published: June 2009

✓ The ability of functional magnetic resonance (MR) imaging to detect a selective sensorimotor cortex activation in healthy subjects and the feasibility of motor activation in patients with lesions around the central sulcus were investigated. Twenty-five healthy volunteers performed 100 motor activation trials, using a variety of motor tasks, which were monitored by several image analysis methods. The functional images were obtained using a 1.5-tesla standard MR imaging system magnet with blood oxygenation level—dependent contrast. Four patients were assessed using functional MR imaging and invasive cortical mapping. Rolandic cortex activation was observed in 98% of the trials performed on healthy subjects in which no head motion occurred. Nevertheless, the cortical response was not selective in a task-rest analysis due to concurrent activation of neighboring regions. Across-task comparison analyses were useful in canceling nonrelevant activity in most cases (86%). In the patient group, the region identified as the sensorimotor cortex by invasive means corresponded accurately to the area that was activated in functional MR imaging. Present data support the feasibility of detecting selective activation of the rolandic cortex, even in the clinical setting, leading the authors to suggest the usefulness of this widely available technique in surgical planning.
Psychosocial functioning and quality of life in patients with primary brain tumors
Authors: Weitzner Michael A. , Meyers Christina A. , Byrne Kevin
Published: June 2009

✓ Perceived quality of life (QOL) was evaluated in a group of 50 patients with primary brain tumors. Participants completed two QOL measures and a demographic profile. Age was found not to be an important factor in differentiating QOL in these patients. All areas of QOL were found to be affected adversely by one or more of five factors: being female, being divorced, having bilateral tumor involvement, having received chemotherapy, and having a poor performance status. Pearson product-moment correlations conducted on the subscale and total scores of the two QOL instruments revealed that the two scales measure different QOL aspects and overlap in only a few areas. This may be related to the different measurement paradigms that these two instruments represent. This study is one of the first to evaluate the multidimensional aspects of QOL in patients with primary brain tumors, an understudied group. A prospective study of QOL in this group, already underway at the authors' institution, is needed to evaluate comprehensively the effect of different treatments and interventions on the QOL functioning of primary brain tumor patients. Additionally, this study shows that the choice of QOL instruments is very important and needs to be driven by the research question.
Ultra-early rebleeding in spontaneous subarachnoid hemorrhage
Authors: Fujii Yukihiko , Takeuchi Shigekazu , Sasaki Osamu , Minakawa Takashi , Koike Tetsuo , Tanaka Ryuichi
Published: June 2009

✓ To determine the incidence of, and risk factors for, the occurrence of rebleeding between admission and early operation (ultra-early rebleeding) in patients with spontaneous subarachnoid hemorrhage (SAH), the authors reviewed the cases of 179 patients admitted within 24 hours after their last attack of SAH. Thirty-one (17.3%) of these patients had ultra-early rebleeding despite scheduling of early operation (within 24 hours after admission). The incidence of rebleeding significantly decreased as the time interval between the last attack and admission increased. Patients with rebleeding before admission, high systolic blood pressure, intracerebral or intraventricular hematoma, those in poor neurological condition on admission, and those who underwent angiography within 6 hours of the last SAH were significantly more likely to have ultra-early rebleeding than those without these factors. The incidence of rebleeding also significantly increased as levels of enhancement of platelet sensitivity and thrombin—antithrombin complex increased. Multivariate analysis revealed that the following three factors were independently associated with ultra-early rebleeding: the level of enhancement of platelet sensitivity; the time interval between the last attack and admission; and the level of thrombin—antithrombin complex. On the basis of these findings, the authors suggest that many of the risk factors for ultra-early rebleeding are interrelated. A particularly high risk of ultra-early rebleeding was observed in those patients 1) who had platelet hypoaggregability; 2) who were admitted shortly after their last SAH; and 3) whose thrombin—antithrombin complex levels were extremely high and were thus in severe clinical condition.