bluuebunny/crossref_metadata_2025 huggingface dataset:
The Emergence of Suicidal Ideation During the Post‐Hospital Treatment of Depressed Patients
Authors: Gaudiano Brandon A. , Andover Margaret S. , Miller Ivan W.
Published: November 2008

There is a paucity of research on the emergence of suicidal ideation in recently hospitalized patients undergoing treatment for depression. As part of a larger clinical trial, patients (N = 103) with major depression without suicidal ideation at hospital discharge were followed for up to 6 months while receiving study‐related outpatient treatments. Fifty‐five percent reported the emergence of suicidal ideation during the outpatient period, with the vast majority (79%) exhibiting this problem within the first 2 months post‐discharge. Seventy percent of those reporting severe suicidality prior to hospitalization exhibited a reemergence of suicidal ideation post‐discharge. However, 29% without significant suicidality at the index hospitalization later developed suicidal ideation during the outpatient treatment period. A faster time to the emergence of suicidal ideation was predicted by both higher prehospitalization levels of suicidal ideation as well as greater depression severity at hospital discharge. Overall, rates of emergent suicidal ideation found in the current sample of recently hospitalized patients were higher than those reported in previous outpatient samples.
Adolescent Suicidal Ideation Subgroups and their Association with Suicidal Plans and Attempts in Young Adulthood
Authors: Rueter Martha A. , Holm Kristen E. , McGeorge Christine R. , Conger Rand D.
Published: November 2008

Suicidal ideation during adolescence is quite common. Longitudinal ideation patterns may predict adolescents at greatest risk of progressing to more serious suicidal behaviors. We enumerated suicidal ideation trajectory subgroups and estimated subgroup association with later suicidal plans and attempts using data collected across a 13‐year period from 552 Caucasian adolescents. Three subgroups were found: non‐ideators (no ideation), decreasers (ideation decreased), and increasers (ideation persisted or increased). Probability of planning a suicide was greatest among increasers (females: .54, males: 51, p < .01). Probability of attempting suicide was greatest among male decreasers (.36, p < .01) and female increasers (.25, p < .01).
University Students' Perceived Self‐Efficacy in Identifying Suicidal Warning Signs and Helping Suicidal Friends Find Campus Intervention Resources
Authors: King Keith A. , Vidourek Rebecca A. , Strader Jennifer L.
Published: November 2008

Currently, suicide is the third leading cause of death among youth 18 to 24 years of age and the second leading cause of death on college campuses. A sample of students (N = 1,019) from three midwestern universities were surveyed regarding their perceived self‐efficacy in identifying suicide warning signs and campus suicide intervention resources. The results indicated that 11% strongly believed they could recognize a friend at suicidal risk, while 17% strongly believed they could ask a friend if he or she was suicidal. Students who had received high school suicide prevention education and who had ever had a family member or friend express suicidal thoughts to them were those most confident in recognizing a friend at risk, asking a friend if he/she is suicidal, and helping a friend to see a counselor. Most (71%) were not aware of on‐campus help resources. These findings underscore the importance of suicide prevention education throughout the high school and college years.
The Construction of Female Sexuality in the ‘Sex Special’
Authors: McLoughlin Linda
Published: November 2008

This article examines two sex specials in British teenage girls’ magazines: Bliss and Sugar from a collection gathered during the period 1995 to 1998. The texts’ producers claim that the material relating to sex is transgressive and offers an emancipatory potential to young women. I argue that the texts, far from being emancipatory, act as regulatory mechanisms by constructing an ideal subject position which accords with the dominant heterosexist ideology. Critical discourse analysis reveals that the ideological messages permeating ‘sex specials’ are deeply rooted in cultural constructions of female sexuality which fail to equip young women for the pressures and complex situations they may face in contemporary society. Focus group discussions with the target readers revealed that the texts were not considered to be transgressive and that their usefulness was extremely limited.
Habitat Selection Influences Sex Distribution, Morphology, Tissue Biochemistry, and Parasite Load of Juvenile Coho Salmon in the West Fork Smith River, Oregon
Authors: Rodnick Kenneth J. , St.‐Hilaire Sophie , Battiprolu Pavan K. , Seiler Steven M. , Kent Michael L. , Powell Madison S. , Ebersole Joseph L.
Published: November 2008

Given the strong influence of water temperature on salmonid physiology and behavior, in the summers of 2004 and 2005 we studied juvenile male and female coho salmon Oncorhynchus kisutch in two reaches of Oregon's West Fork Smith River with different thermal profiles. Our goals were to compare the body morphology, tissue biochemistry, genetics, and parasite load and determine whether sex, tissue biochemistry, and infection with multiple parasite species influence swimming performance. Sex differences in habitat selection distribution were apparent; proportionately more females occupied the cooler, upper reach, and males predominated in the warmer, lower reach. Despite having similar genotypes, fish in the upper reach had deeper bodies and higher condition factors, regardless of sex. These fish also had higher blood lipids and elevated citrate synthase activity in epaxial white muscle, suggesting a greater potential for aerobic metabolism. Critical swimming speeds measured streamside at 18°C and endurance time were influenced by sex, females performing much better than males. Plasma lactate levels were inversely correlated with swimming performance, indicating that females relied more on aerobic metabolism for energy production. We also found a high prevalence of tissue‐specific myxozoans (Myxobolus insidiosus and M. kistuchi) and larval trematodes (Nanophyetus salmincola and Apophallus sp.) in the muscle and “black spot” in the skin. The prevalence of these parasites was higher in the warmer, lower reach than in the upper reach and the lower‐reach fish lower condition indices. The degree of parasitism was not correlated with the swimming ability or sex of fish.
Potential Effects of Striped Bass Predation on Juvenile Fish in the Hudson River
Authors: Heimbuch Douglas G.
Published: November 2008

This study addressed the question whether the increase in the abundance of striped bass Morone saxatilis in the Hudson River that began after 1990 and the associated increase in predatory demand could have been responsible for the observed declines in the abundance of juvenile river herring (i.e., blueback herring Alosa aestivalis and alewife A. pseudoharengus), Atlantic tomcod Microgadus tomcod, and white perch Morone americana as well as the apparent decline in the survival of juvenile striped bass in the Hudson River. The seasonal (August through October) predatory demand of Hudson River striped bass (ages 1‐13) was estimated to have increased from an average of 3.4 million kg/year for the period 1982‐1990 to an average of 15.0 million kg/year for the period 1991‐2004. Since 1990, the average abundance of juvenile fish in the Hudson River has declined—60% for river herring, 69% for Atlantic tomcod, and 59% for white perch—and juvenile striped bass survival has declined 87%. These declines could be explained by the increase in striped bass predatory demand if (1) 3.3% of the seasonal predatory demand of age‐1 to age‐13 striped bass was satisfied by consumption of juveniles of the four taxa or (2) 11.1% of the seasonal predatory demand of age‐1 and age‐2 Hudson River striped bass was satisfied by consumption of juveniles of the four taxa. Historical information on the fraction of the Hudson River striped bass stock that inhabits the Hudson River from August through October, combined with the dietary preferences of Hudson River striped bass, appear to be consistent with these levels of consumption.
Successful Control of High-Pressure Gas Well by Use of a Crosslinked Gel During Coiled-Tubing Fishing
Authors: Nwoke Linus , Arukhe James , Uchendu Chike
Published: November 2008

Good well- and reservoir-management practices demand that new gas wells be tested to expected potentials at the onset of production and buildup surveys be conducted at specified intervals during the life of the well. This will help to determine the deliverability of the wells, obtain base reservoir parameters, and improve reservoir surveillance in monitoring abandonment conditions. It was the pursuit of these data gatherings that lead to the multirate buildup survey that resulted in stuck temperature and pressure memory gauges at RN® No-Go nipple.

The gas-production capability of this well was estimated at 150 MMscf/D. After the installation of the memory gauges, multirate and 10-hour buildup tests were conducted. During the retrieval of the bottomhole-pressure (BHP) gauges, several incidents led to three fish getting stuck successively in the wellbore. The operator was faced with many options, each with a limitation: Continue the well in an unsafe manner at 50% potential, attempt a workover, or attempt a coiled-tubing (CT) rigless intervention.

During the planning stage of the remedial operation, success in retrieving the multiple fish was identified to be dependent upon the ability to kill the high-pressure gas well with a time-dependent and acid-degradable crosslinked-gel system with a high-rate bullhead pumping technique and appropriate wireline/CT fishing tools. These tools would locate and grab the wire rope simultaneously, minimizing run time in a cost-effective manner. The kill fluid needed to have low damage potential to the formation and be capable of preventing the migration and fingering of formation gas to the surface throughout the fishing operation, which lasted approximately 1 month. Key success was identified in the ability of the CT to compress the wire rope in bunches and withstand the extra overpull required to free the stuck fish.

At the end of the operation, in which some challenges were encountered, five stuck fish (two additional fish became stuck during the attempt to free the first three) were retrieved successfully and prefishing conduit potential was retained, thus indicating that the crosslinked gel degraded completely at the end of the fishing operation, leaving the near-wellbore region undamaged.

The gain from the operation includes leaving the formation in an undamaged state, cost savings, high net present value, and meeting the gas-supply obligation. More than USD 2.0 million was saved operationally with the choice of rigless activity when compared to the rig re-entry alternative. The well is still producing satisfactorily 5 years after this activity.

This paper presents the engineering design and field application of, as well as lessons learned from, fishing operations.
Results of the World&s First 4D Microgravity Surveillance of a Waterflood-Prudhoe Bay, Alaska
Authors: Brady J. L. , Hare J. L. , Ferguson J. F. , Seibert J. E. , Klopping F. J. , Chen T. , Niebauer T.
Published: November 2008

The world's first 4D surface-gravity surveillance of a1 waterflood has been implemented at Prudhoe Bay, Alaska. This monitoring technique is an essential component of the surveillance program for the Gas Cap Water Injection (GCWI) project. A major factor in the approval process for the waterflood was to show that we could monitor water movement economically where a very limited number of wells penetrated the waterflood area. The drilling of numerous surveillence wells to monitor water movement adequately would have been cost-prohibitive. Field surveys now show conclusively that density changes associated with water replacing gas are being detected readily with high-resolution surface-gravity measurements. The gravity methods used to monitor the water-flood include time-lapse (4D) measurement of surface gravity over the reservoir followed by inversion of the 4D signal for mass-balance calculation and flood-front detection.

This paper will focus on field results of time-lapse surface-gravity surveys. Differences in the gravity field over time reflect changes in the reservoir-fluid density. The inversion procedure was formulated and coded to allow for various constraints on model parameters such as density, total mass, and moment of inertia. The gravity survey was designed to permit the inversion for reservoir mass distribution, with resolution on the order of hundreds of meters in the presence of uncorrelated noise of reasonable magnitude (12-μGal standard deviation).

Time-differenced gravity-survey results clearly show an increase in surface gravity that is a result of the injected-water mass. Density-change maps deduced from measured gravity change show that water movement is reasonably similar to the reservoir simulations and to the water detected in observation wells. The overall ultimate gravity signal is predicted to increase to approximately 250 μGal, ultimately resulting in accurate maps of the water movement.
Quantifying the Reliability and Value of 3D Land Seismic
Authors: Bickel J. Eric , Gibson Richard L. , McVay Duane A. , Pickering Stephen , Waggoner John
Published: November 2008

Seismic data provide essential information for guiding reservoir development. Improvements in data quality hold the promise of improving performance even further, provided that the value of these data exceeds their cost. Previous work has demonstrated value-of-information (VOI) methods to quantify the value of seismic data. In these examples, seismic accuracy was obtained by means of expert assessment instead of being based on geophysical quantities. In addition, the modeled seismic information was not representative of any quantity that would be observed in a seismic image.

Here we apply a more general VOI model that includes multiple targets, budgetary constraints, and quantitative models relating poststack seismic amplitudes and amplitude-variation-withoffset (AVO) parameters to the quantities of interest for reservoir characterization, such as porosity and reservoir thickness. Also, by including estimated changes in data accuracy based on signal-tonoise ratio, the decision model can provide objective estimates of the reliability of measurements derived from the seismic data. We demonstrate this methodology within the context of a west Texas 3D land survey. This example demonstrates that seismic information can improve reservoir economics and that improvements in seismic technology can create additional value.
A Model for Gas Coning and Rate-Dependent Gas/Oil Ratio in an Oil-Rim Reservoir
Authors: Mjaavatten Are , Aasheim Robert , Saelid Steinar , Grønning Oddvar
Published: November 2008

In oil-rim fields, a thin oil layer lies between an aquifer and a gas cap. Oil may be produced from such fields by use of horizontal wells. Production will lower the local gas/oil contact (GOC) near the well in a process called gas coning. After gas breakthrough, the gas/oil ratio (GOR) from the well may vary strongly with the production rate. The ability to predict this dependency is essential for production optimization for such fields.

We have developed a mathematical model that can predict gas-coning behavior and the resulting rate-dependent GOR for periods of several months or more. Despite a simple model structure and short computation times, the accuracy of the predictions is good. We combine a dynamic model that describes the essential reservoir behavior with a highly simplified description of the interaction between the well and the surrounding reservoir. The full model has three adjustable parameters that allow us to fit the behavior to individual wells, using historical oil-and gas-production rates. The model forms the basis of the GORM (gas/oil ratio model) computer program that, since early 2003, is in regular use for production planning and optimization at the Troll field. We also have tested the model on wells in other fields, with encouraging results.

Note that the model describes the behavior of individual wells only. The focus is short-and medium-time production optimization, not reservoir management.
Analyzing Underperformance of Tortuous Horizontal Wells: Validation With Field Data
Authors: Kerem M. , Proot M. , Oudeman P.
Published: November 2008

This paper presents the results of a project that was initiated to analyze the inflow performance and inflow distribution of one smart and two problematic conventional, long, and tortuous horizontal wells in Brunei.

Following a detailed hydraulic analysis of these wells, a good match with field measurements was obtained. Simulation results show that the problems in the conventional wells were not as severe as those interpreted from the measurements of distributed temperature sensing systems (DTSs). It is also demonstrated that the compartmentalized completion with inflow control valves (ICVs) in the smart well has added value, because the well would not be producing from over half of the reservoir section without the smart completion.
Maximum-Reservoir-Contact-Wells Performance Update: Shaybah Field, Saudi Arabia
Authors: Salamy S. P. , Al-Mubarak H. K. , Al-Ghamdi M. S. , Hembling D.
Published: November 2008

This paper is an update on previous SPE technical papers (Saleri et al. 2003; Saleri et al. 2004) highlighting the results of 25 maximum-reservoir-contact (MRC) wells drilled in the Shaybah field either as new wells or as part of a workover strategy to convert existing weak 1-km single-lateral wells to MRC wells with reservoir contacts ranging from 5 to 9 km.

Shaybah field in Saudi Arabia, a low-permeability reservoir overlain by a large gas cap, was developed initially in 1996 with 1-km single-lateral horizontal wells to drain hydrocarbon while reducing gas coning effectively. A step-development approach of increasing reservoir contact to improve well productivity and performance was the basis for the MRC concept. To date, results from 25 MRC wells have indicated a four-fold increase in well productivities and a three-fold decrease in unit-development cost when compared to the 1-km single-lateral wells. A useful byproduct of MRC drilling is the enhancement achieved in reservoir characterization.

In addition to MRC wells, smart technologies such as down-hole-flow-control systems (smart completions), expandable liners, and production equalizers were deployed in Shaybah field. These technologies have improved well performance and recovery greatly. Smart controls assisted in optimizing production from each lateral in a multilateral (ML) well in the event of premature gas or water coning. In addition, downhole smart completions improved well productivity in ML wells with a better well-cleanup process. Production equalizers that were deployed in high-gas/oil-ratio (GOR) wells reduced gas coning and improved well productivity. To date, more than 21 expandable liners have been deployed as enablers to a workover strategy to convert single-lateral wells to ML/MRC wells, thereby providing a platform for installation of downhole-flow-control systems.
Haradh-III: Industry's Largest Field Development With Maximum-Reservoir-Contact Wells, Smart-Well Completions, and the iField Concept
Authors: Al-Kaabi Abdulaziz O. , Afaleg Nabeel I. , Pham Tony , Al-Muallem Ali S. , Al-Bani Fahad A. , Hart Richard G. , Hembling Drew E.
Published: November 2008

The development of Haradh-III in the southernmost region of Ghawar represents a major shift in paradigm in terms of the combination of the technologies. The field development combines four main technology features, which include maximum-reservoir-contact (MRC) wells, smart completions, extensive use of real-time geosteering, and iField initiatives.

This paper describes the motivation, implementation, and post-production evaluation of this unique field development. In the case of Haradh-III, field development with smart MRC wells delays water encroachment, improves flood-front conformance and recovery, and lowers water production and long-term development and operating costs. Bottomwater encroachment into the wellbore is mitigated as downhole internal control valves (ICVs), as part of the smart completion, are adjusted. This, in turn, lengthens the life of the well, allowing sweep and recovery to take place in the reservoir below the horizontal wellbores with the most effective sweep process: the replacement mechanism by gravity. The objectives of the development are accomplished by use of a reduced number of wells that minimize the accompanying infrastructure, which lowers the capital expenditure while reducing the operating cost by maintaining, on a long-term basis, a low-water-producing system, all in real time and within the iField environment.
The Event Solution—A New Approach for Fully Integrated Studies Covering Uncertainty Analysis and Risk Assessment
Authors: Elrafie Emad , White Jerry , Awami Fatema
Published: November 2008

Saudi Aramco strives to implement new and innovative techniques and approaches to assist in meeting the industry's increasing challenges. One of these is the new study approach, "the Event Solution," which leads to better synergy among different stakeholders and enables faster decisions that fully encompass the complex uncertainties associated with today's gasfield and oilfield developments.

The Event Solution is a short, intensively collaborative event, which compresses major decision cycles, embraces uncertainty, and provides a wider range of alternative solutions. The Event Solution approach has been implemented successfully on 24 major studies worldwide, with the last eight projects conducted on Saudi Aramco megareservoirs.

The concept is simple: Identify the most important study objective, and focus the collective skills and creativity of a team of experts to meet the study objective in a special event that lasts just for 2 months. The team is enabled with the latest hardware and software technologies in a large team room, specially designed for collaboration, where they can work together. A facilitator leads the team to implement the Event Solution process that helps the team to see "the big picture" and understand what matters to the bottom line. The team composition is enriched with representatives from all of the stakeholders (including technical experts, management, facilitators, and sometimes government and joint-venture partner's representatives) so the results can be concluded and implemented immediately, with maximum buy-in.

The Event Solution process includes detailed uncertainty analysis and risk-assessment workflows that have been implemented successfully in many events. The most important deliverable of the Event Solution, however, is that all the stakeholders develop a clear and common understanding of the critical uncertainties, project risk, and the agreed plans to move forward—the decisions. This volume of work, which traditionally requires years, is completed in 2 months on average using the Event Solution process.

This paper presents the elements and processes of this new approach. Critical elements to a successful Event Solution include software, workroom, team members, and a facilitator. Once the elements are in place, the facilitator leads the team through processes that include project preparation, parallel workflows, uncertainty analysis, critical information plans, project risk assessment, and mitigation plans. Note that uncertainty analysis is not a simple byproduct of the study, but an integral component of success.
Total-Property Modeling: Dispelling the Net-to-Gross Myth
Authors: Ringrose Philip S.
Published: November 2008

Reservoir-modeling practice has developed into a complex set of numerical algorithms and recipes for modeling subsurface geology and fluid flow. Within these workflows, a number of myths have sometimes been propagated, especially in relation to (a) methods for handling net-to-gross (N/G), (b) implementation of upscaling methods, and (c) conditioning of reservoir models to well data. This paper discusses different practices in the use and upscaling of reservoir data and models, by comparing two end-member approaches: (1) the N/G method and (2) total-property modeling. Total property modeling, in which all rock elements are represented explicitly, is the generally preferred method. The N/G method involves a simplified representation of reality, which may be an acceptable approximation. Implications for upscaling and conditioning reservoir models to well data are discussed, and recommended practices are suggested.
An Improved Model for the Liquid-Loading Process in Gas Wells
Authors: Van Gool Frank , Currie Peter K.
Published: November 2008

This paper introduces an improved model for describing the liquid-loading process in gas wells. The model is an extension of the model proposed by Dousi et al. (2006).

The Dousi model handles the downhole inflow and outflow between the well and the reservoir in a simple manner. The new model improves this aspect and makes more-realistic and -detailed assumptions with respect to the production and injection interval. Analysis of the results this new model produces improves the understanding of the processes occurring down-ole. This analysis can also be used to predict future behavior of the well in a more realistic fashion. As in the Dousi model, two typical flow rates could be found, with one at full production with all the fluids produced to the surface and the other one a metastable rate in which produced fluids are being reinjected into the reservoir. Field observations confirm the existence of two possible flow rates in many wells. The difference between the new model and the Dousi model is that changes in flow rates occur more slowly when liquid loading starts, reflecting the more-realistic inflow-performance assumptions.

With this model, liquid-loading processes in the well can be understood better and predicted. This is important for optimization of well performance and for the economic assessment of the well and field.
Simultaneous Acid Diversion and Water Control in Carbonate Reservoirs: A Case History From Saudi Arabia
Authors: Al-Taq Ali A. , Nasr-El-Din Hisham A. , Beresky Jimmy K. , Naimi Khalid M. , Sierra Leopoldo , Eoff Larry
Published: November 2008

Matrix acidizing and water control are usually addressed as two separate issues. Associative polymers can be used to simultaneously achieve effective acidizing and water control during a single treatment. A polymer-based treatment was applied in an offshore, perforated vertical well with two sets of perforations in a carbonate reservoir in Saudi Arabia. The acid treatment was needed to restore the productivity of the upper set of perforations and reduce water production from the lower set of perforations.

Experimental studies were carried out to investigate the potential use of associative polymers to control water mobility and act as an acid diverter. Coreflood experiments were conducted on reservoir cores at downhole conditions (temperature of 200°F and pressure of 3,500 psi). Extensive laboratory testing showed that associative polymers had no significant effect on the relative permeability to oil. However, the relative permeability to water was significantly reduced.

This paper presents a case history where an associative polymer was applied during matrix acid treatment of a damaged well. The treatment included two stages of associative polymer solutions and 20 wt% HCl with additives. Post-stimulation treatment production data showed that oil rate increased 11.18-fold, whereas water rate decreased 1.7-fold, resulting in a reduction in the water cut from 75 to 14 vol%.

The production logging tool (PLT) results indicated that the associative polymer was effective in diverting the acid into the oil producing zone. The upper set of perforations was producing most of the fluid, which further confirmed that the associative polymer significantly reduced water production from the lower zone.
Injectivity Decline From Produced-Water Reinjection: New Insights on In-Depth Particle-Deposition Mechanisms
Authors: Rousseau D. , Hadi L. , Nabzar L.
Published: November 2008

Injectivity decline during produced-water reinjection (PWRI) originates not only from filter-cake buildup but also from in-depth deposition of oil droplets or solid particles. Physical modeling of particle-deposition mechanisms in porous media is thus of key interest for optimizing PWRI operations. The present work brings new insights on oil-droplet and solid-particle-deposition mechanisms in porous media.

The experimental conditions were selected such that the ratio between pores and particle sizes is sufficiently large to ensure in-depth propagation. The parameters are the nature of the particles injected and a Peclet number calculated on the size of the collector grains (Peg) that encompasses in a nondimensional form the impact of both the flow rate and the particle size.

The results are analyzed within the framework of the "colloidal approach." For oil droplets and solid particles, the collection efficiency (η) shows a transition from a behavior in which η varies as a power law of Peg, with exponent values −⅔ [(diffusion-limited deposition (DLD)] to −1 [reaction-limited deposition (RLD)] that are typical of the convection/diffusion regime, to a behavior characterized by an increase of η vs. Peg, typical of the hydrodynamic deposition regime. In the case of oil droplets (slightly charged), the transition occurs at a critical Peg value, PegC≈PegCgeom/10, corresponding to a diffusion-layer thickness around the collector grain of the same order of magnitude as the droplet diameter. In the case of electrosterically stabilized solid particles, the transition takes place at PegC≪PegCgeom for small particles and at PegC>PegCgeom for larger particles.
Nanotechnology Applications in Viscoelastic Surfactant Stimulation Fluids
Authors: Huang Tianping , Crews James B.
Published: November 2008

Viscoelastic surfactant (VES) fluids have been used widely in the oil industry as completion and stimulation fluids. The surfactants arrange structurally to form rod-like micelles that increase VES-fluid viscosity for regular fracturing and fracture-packing fluids. However, high fluid leakoff and low viscosities at elevated temperatures have limited VES fluids to hydraulic fracturing and fracture-packing applications.

This paper will introduce a nanotechnology application for maintaining viscosity at high temperatures and controlling the loss of VES fluid without generating formation damage. The nanoparticles studied are 35-nm inorganic crystals that display unique surface morphology and surface reactivity. These nanometer-scale particles associate with VES micelles through chemisorption and surface-charge attraction to stabilize fluid viscosity at high temperatures and to produce a pseudofilter cake of viscous VES fluid that reduces significantly the rate of fluid loss and improves fluid efficiency. When internal breakers are used to break the VES micelles, the fluid will lose its viscosity dramatically and the pseudofilter cake will then break into brine and nanoparticles. Because the particles are small enough to pass through the pore throat of producing formations, they will be flowed back with the producing fluids, and no damage will be generated. The results of rheology, leakoff, and core-flow tests will be presented for the VES-fluid systems at temperatures 150 and 250°F.
IPO Gas Lift Design With Valve Performance
Authors: Decker Kenneth L.
Published: November 2008

Although gas lift design has been practiced for many years with the use of the Thornhill Craver (TC) equation (Cook and Dotterweich 1946) to predict the rate of gas passage through a gas-lift-valve port, the equation and charts were never intended for use with live gas lift valves.

It is now possible to obtain tested valve-gas-passage-performance data for any pressure and temperature conditions. To date, a method has not been provided for the use of this information during the design stage.

This paper will show how tested valve-performance data can be used in the design of 1-in. (25.4-mm) injection-pressure-operated (IPO) gas-lift valves.
Effects of Reservoir Heterogeneities on the Steam-Assisted Gravity-Drainage Process
Authors: Chen Q. , Gerritsen M. G. , Kovscek A. R.
Published: November 2008

The success of steam-assisted gravity drainage (SAGD) has been demonstrated by both field and laboratory studies mostly on the basis of homogeneous reservoirs and reservoir models. A comprehensive understanding of the effects of reservoir heterogeneities on SAGD performance is required, however, for wider and more-successful implementation. This work presents a numerical investigation of the effects of reservoir heterogeneities on SAGD using a stochastic model of shale distribution. Two flow regions, the near-well region (NWR) and the above-well region (AWR), are identified to decouple the complex effects of reservoir heterogeneities on the SAGD process. Numerical simulations are conducted with various realizations of shale distribution to compare SAGD performance in terms of the effects of NWR and AWR. Hydraulic fracturing is proposed to enhance steam-chamber development for reservoirs with poor vertical communication, and the feasibility of hydraulic fracturing is discussed in terms of in-situ stress and well orientation. Fracturing both injectors and producers is found to improve steam distribution, oil production rate, and the oil-steam ratio.
Thermal stress analysis on laser scribing of glass
Authors: Yamamoto Koji , Hasaka Noboru , Morita Hideki , Ohmura Etsuji
Published: November 2008

In the laser scribing of glass a thermal stress is introduced into a glass substrate by means of a CO2 laser irradiation. The glass substrate is then rapidly cooled down by water jet immediately after the irradiation. For the purpose of theoretical clarification of the factors ruling the scribable condition and the crack depth, scribable conditions were acquired in laser irradiation experiments using a soda-lime glass substrate having a thickness of 0.7 mm. Furthermore, the crack depth and the crack edge profile were observed for various values of the distance between the heating area and the cooling area. On the basis of the scribable conditions obtained from the experiments results, a thermal elasticity analysis was conducted by a finite element method. The following results were obtained. The scribable condition can be estimated from the maximum tensile stress in the cooling area and the maximum temperature in the heating area. The crack depth in laser scribing depends on the tensile stress in the cooling area and the compressive stress field immediately under the area.
Effect of Nd:Yttrium-aluminum-garnet laser radiation on Ti6Al4V alloy properties for biomedical applications
Authors: Khosroshahi M. E. , Mahmoodi M. , Tavakoli J. , Tahriri M.
Published: November 2008

The effect of Nd:yttrium-aluminum-garnet laser on the microtopography and physicochemical properties of Ti6Al4V alloy are investigated in the view of biomedical applications. The surface roughness and hardness for laser treated samples (LTS) at 140 J cm−2 were measured 7±0.02 and 825 vickers hardness number, respectively. This superior microhardness value is attributed to grain refinement associated with laser melting and rapid solidification. The electrochemical property, mainly pitting corrosion resistance, has been carried out in Hanks salt balanced physiological solution using standard potentiodynamic polarization testing. A higher corrosion potential of −0.21 V was achieved for LTS. At the optimium treating value of laser fluence (140 J cm−2), the energy dispersive x-ray analysis showed about a 30% decrease of vanadium. The contact angle measurements also indicated an improved surface wettability (i.e., hydrophilicity) characteristic at 35°. Finally, the cell culture studies provided a useful tool to investigate the morphology and cell cytotoxicity.
Considerations for reflective laser eye protection against ultrafast lasers
Authors: Tribble J.
Published: November 2008

The inherently broad spectral bandwidth of ultrafast (mode locked) lasers can potentially exceed the protection bandwidth of laser eye protection. This is a particular concern for reflective laser eye protection technologies which by design possess sharp often narrow spectral protection notches. The purpose of this paper is to report spectral transmittance of an ultrafast laser through an interference filter typifying those currently used in laser eye protection and to examine the impact of spectral and angular leakage on the level of protection provided.
Keyhole welding studies with a moderate-power, high-brightness fiber laser
Authors: Brown R. T.
Published: November 2008

Bead-on-plate welding tests were performed using a 600 W fiber-delivered fiber laser. Uniform, high-aspect-ratio keyhole welds were observed in 1018 low-carbon steel, 1100 aluminum, and 304 stainless steel. The Rosenthal two-dimensional thermal model for a moving-line heat source was effective in predicting weld width for both partial-penetration and full-penetration welds. By setting the temperature at the perimeter of the keyhole equal to the vaporization temperature, this same model provided a first-order estimate of the weld depth for partial-penetration welds, as well. The two-dimensional model was used to calculate the steady-state temperature field associated with the welding process as well as the temporal thermal history of points in the weld pool and in the heat-affected zone next to the weld pool. A comparison of calculated weld-bead geometries with dimensions scaled from micrographs of bead cross sections showed reasonable agreement.
Veterinarian-client-patient communication during wellness appointments versus appointments related to a health problem in companion animal practice
Authors: Shaw Jane R. , Adams Cindy L. , Bonnett Brenda N. , Larson Susan , Roter Debra L.
Published: November 2008

Objective—To compare the clinical interview process, content of the medical dialog, and emotional tone of the veterinarian-client-patient interaction during wellness appointments and appointments related to a health problem in companion animal practice.

Design—Cross-sectional descriptive study.

Sample Population—A random sample of 50 companion animal practitioners in southern Ontario and a convenience sample of 300 clients and their pets.

Procedure—For each practitioner, 6 clinical appointments (3 wellness appointments and 3 problem appointments) were videotaped. The Roter interaction analysis system was used to analyze the resulting 300 videotapes.

Results—Wellness appointments were characterized by a broad discussion of topics, with 50% of data-gathering statements and 27% of client education statements related to the pet's lifestyle activities and social interactions. Wellness appointments included twice as much verbal interaction with the pet as did problem appointments, and the emotional atmosphere of wellness appointments was generally relaxed. There were more social talk, laughter, statements of reassurance, and compliments directed toward the client and pet. In contrast, during problem appointments, 90% of the data gathering and client education focused on biomedical topics. Coders rated veterinarians as hurried during 30 of the 150 (20%) problem appointments; they rated clients as anxious during 39 (26%) problem appointments and as emotionally distressed during 21 (14%).

Conclusions and Clinical Relevance—Results suggested that veterinarian-client-patient communication differed between wellness and problem appointments. Owing to the emphasis on biomedical content during problem appointments, veterinarians may neglect lifestyle and social concerns that could impact patient management and outcomes, such as client satisfaction and adherence to veterinarian recommendations.
Agreement between direct and indirect blood pressure measurements obtained from anesthetized Hispaniolan Amazon parrots
Authors: Acierno Mark J. , da Cunha Anderson , Smith Julie , Tully Thomas N. , Guzman David Sanchez-Migallon , Serra Verna , Mitchell Mark A.
Published: November 2008

Objective—To determine the level of agreement between direct and indirect blood pressure measurements obtained from healthy Hispaniolan Amazon parrots (Amazona ventralis) anesthetized with isoflurane.

Design—Validation study.

Animals—16 healthy adult Hispaniolan Amazon parrots.

Procedures—Parrots were anesthetized, and a 26-gauge, 19-mm catheter was placed percutaneously in the superficial ulnar artery for direct measurement of systolic, mean, and diastolic arterial pressures. Indirect blood pressure measurements were obtained with a Doppler ultrasonic flow detector and an oscillometric unit. The Bland-Altman method was used to compare direct and indirect blood pressure values.

Results—There was substantial disagreement between direct systolic arterial blood pressure and indirect blood pressure measurements obtained with the Doppler detector from the wing (bias, 24 mm Hg; limits of agreement, −37 to 85 mm Hg) and from the leg (bias, 14 mm Hg; limits of agreement, −14 to 42 mm Hg). Attempts to obtain indirect blood pressure measurements with the oscillometric unit were unsuccessful.

Conclusions and Clinical Relevance—Results suggested that there was substantial disagreement between indirect blood pressure measurements obtained with a Doppler ultrasonic flow detector in anesthetized Hispaniolan Amazon parrots and directly measured systolic arterial blood pressure.
Etiologic classification of seizures, signalment, clinical signs, and outcome in cats with seizure disorders: 91 cases (2000–2004)
Authors: Schriefl Simone , Steinberg Tanja A. , Matiasek Kaspar , Ossig Andrea , Fenske Nora , Fischer Andrea
Published: November 2008

Objective—To evaluate associations among etiologic classifications of seizures and signalment, clinical signs, and outcome in cats with various seizure disorders.

Study Design—Retrospective case series.

Animals—91 cats evaluated for seizure disorders at a veterinary teaching hospital from 2000 through 2004.

Procedures—Data regarding characteristics of the cats and their seizures were obtained from medical records. Seizures were classified as reactive, symptomatic, or idiopathic. Survival times were displayed as Kaplan-Meier curves, and differences between etiologic classifications were assessed by log-rank test.

Results—Over the 5-year period, the incidence of seizures among all cats evaluated at the hospital was 2.1%. Etiology was classified as reactive in 20 (22%) cats, symptomatic in 45 (50%), idiopathic or presumptive idiopathic in 23 (25%), and cardiac syncope in 3 (3%). Focal seizures with or without secondary generalization were recorded for 47 (52%) cats, and primary generalized seizures with or without status epilepticus were recorded for 44 (48%). Etiology was not associated with seizure type. However, mean age of cats with idiopathic seizures (3.5 years) was significantly lower than that of cats with reactive seizures (8.2 years) or symptomatic seizures (8.1 years). The 1-year survival rate for cats with idiopathic seizures (0.82) was longer than that for cats with reactive (0.50) or symptomatic (0.16) seizures.

Conclusions and Clinical Relevance—Seizure etiology was symptomatic or reactive in most cats. Underlying disease was not associated with seizure type. Cats with idiopathic seizures lived longer than did cats with reactive or symptomatic seizures but were also younger.
Mandibular reconstruction after gunshot trauma in a dog by use of recombinant human bone morphogenetic protein-2
Authors: Lewis John R. , Boudrieau Randy J. , Reiter Alexander M. , Seeherman Howard J. , Gilley Robert S.
Published: November 2008

Case Description—A 6-year-old German Shorthaired Pointer was evaluated for possible reconstruction of a mandibular defect resulting from gunshot trauma.

Clinical Findings—A 5-cm defect of the right mandibular body was evident. A segment of the mandibular body was removed 9 weeks earlier because of severe contamination and comminution associated with gunshot trauma. Subsequent right-sided mandibular drift resulted in malocclusion in which the left mandibular canine tooth caused trauma to mucosa of the hard palate medial to the left maxillary canine tooth. The right maxillary canine tooth caused trauma to gingiva lingual to the right mandibular canine tooth.

Treatment and Outcome—The right mandible was stabilized with a 2.0-mm maxillofacial miniplate positioned along the lateral alveolar margin and a 2.4-mm locking mandibular reconstruction plate placed along the ventrolateral mandible. An absorbable compressionresistant matrix containing collagen, hydroxyapatite, and tricalcium phosphate was soaked in recombinant human bone morphogenetic protein-2 (rhBMP-2; 7.2 mL of a 0.5 mg/mL solution for a dose of 3.6 mg) and placed in the defect. By 4 weeks after surgery, an exuberant callus was evident at the site of the defect. By 7 months after surgery, the callus had remodeled, resulting in normal appearance, normal occlusion, and excellent function of the jaw.

Clinical Relevance—Mandibular defects resulting from gunshot trauma can be treated by removal of contaminated tissue and comminuted bone fragments, followed by staged reconstruction. The combination of rhBMP-2 and compression-resistant matrix was effective in a staged mandibular reconstruction in a dog with a severe traumatic mandibular defect.
Evaluation of risk factors, management, and outcome associated with rectal tears in horses: 99 cases (1985–2006)
Authors: Claes Anthony , Ball Barry A. , Brown James A. , Kass Philip H.
Published: November 2008

Objective—To identify risk factors for rectal tears in horses; assess the effect of initiating cause on tear location, size, and distance from anus; and determine short-term survival rate among horses with various grades of rectal tears.

Design—Retrospective case series.

Animals—99 horses.

Procedures—Medical records for horses with a rectal tear were reviewed, and data including age; sex; breed; cause, location, and size of the tear and its distance from the anus; tear grade; treatment; and outcome (short-term survival [ie, survival to discharge from the hospital] vs nonsurvival) were recorded. Data for age, sex, and breed of horses with rectal tears were compared with data for all horses evaluated at the hospital during the same interval to determine risk factors for rectal tears.

Results—Arabians, American Miniature Horses, mares, and horses > 9 years of age were more likely to develop a rectal tear than other breeds, males, or younger horses. Dystocia had a significant influence on rectal tear size. Location of a rectal tear and its distance from the anus were not associated with cause. Applied treatments for grade 1, 2, and 3 rectal tears were effective, unlike treatments for grade 4 rectal tears. Irrespective of treatment, the overall short-term survival rate among horses with grade 1, 2, 3, and 4 rectal tears was 100%, 100%, 38%, and 2%, respectively.

Conclusions and Clinical Relevance—Accurate identification of risk factors could help practitioners and owners implement adequate measures to prevent the development of rectal tears in horses.