bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical simulation of nozzle flow field with jet vane thrust vector control
Authors: Murty M S R C , Rao M S , Chakraborty D
Published: December 2009

Numerical simulations are performed to characterize the jet vane thrust vector control mounted in the rear of a rocket motor. The three-dimensional Navier—Stokes equations along with the K—ε turbulence model are solved in a hybrid mesh consisting of an unstructured grid and a structured grid. All essential flow features including the complex compression/expansion wave interactions emanating from the vane surfaces and shrouds are captured by simulation. The computed side force coefficients are seen to vary linearly with chamber pressure and vane deflection angles. A theoretical correlation has been developed by a non-linear regression analysis from the computational fluid dynamics (CFD) database to predict the force and moment coefficients for different chamber pressures, vane deflection angle, and roll offset angle. The theoretical correlation compare very well with full CFD simulation as well as the experimental data.
Inflation-Gap Persistence in the US
Authors: Cogley Timothy , Primiceri Giorgio E. , Sargent Thomas J.
Published: December 2009

We estimate vector autoregressions with drifting coefficients and stochastic volatility to investigate whether US inflation persistence has changed. We focus on the inflation gap, defined as the difference between inflation and trend inflation, and we measure persistence in terms of short- to medium-term predictability. We present evidence that inflation-gap persistence increased during the Great Inflation and that it fell after the Volcker disinflation. We interpret these changes using a dynamic new Keynesian model that highlights the importance of changes in the central bank's inflation target. (JEL E12, E31, E52, E58)
Why Are Saving Rates of Urban Households in China Rising?
Authors: Chamon Marcos D. , Prasad Eswar S.
Published: December 2009

From 1995 to 2005, the average urban household savings rate in China rose by 7 percentage points, to about one-quarter of disposable income. Savings rates increased across all demographic groups, and the age profile of savings has an unusual pattern in recent years, with younger and older households having relatively high savings rates. We argue that these patterns are best explained by the rising private burden of expenditures on housing, education, and health care. These effects and precautionary motives may have been amplified by financial underdevelopment, including constraints on borrowing against future income and low returns on financial assets. (JEL D14, E21, O12, O18, P25, P36)
Are primary care-based sexually transmitted infection services in the UK delivering public health benefit?
Authors: Bailey A C , Johnson S A , Cassell J A
Published: December 2009

Sexual health services in primary care, known in the UK as local enhanced services in sexual health (LESSH), aim to increase access to sexually transmitted infection (STI) screening and treatment. Little is known about the characteristics, quality or public health impact of these services. We identified national standards for service provision, and evaluated LESSH against them using a structure, process and outcome approach. Clinical structure and process standards were generally well met, with the exception of partner notification provision. However, public health and outcome measures were largely unascertainable and often undefined in the standards. If the primary care STI services are to deliver public health benefit, improved outcome measures and data collection are required.
The untold neurological disease of Franklin Delano Roosevelt (1882–1945)
Authors: Lomazow Steven
Published: December 2009

Conventional wisdom suggests that Franklin Delano Roosevelt died on 12 April 1945 aged 63 from a massive cerebral haemorrhage attributable to uncontrolled hypertension and atherosclerosis. Evidence from numerous reliable sources is presented, based largely on a constellation of previously unrecognized neurological symptoms including seizures, encephalopathy and hemianopia, supporting a scenario that, while indeed he suffered from severe cardiovascular disease, Roosevelt died from melanoma with the terminal event attributable to a metastatic lesion in the brain.
Effect of a Pharmacy-Based Health Literacy Intervention and Patient Characteristics on Medication Refill Adherence in an Urban Health System
Authors: Gazmararian Julie , Jacobson Kara L , Pan Yi , Schmotzer Brian , Kripalani Sunil
Published: December 2009

BACKGROUND

Limited health literacy is associated with poor understanding of medication instructions and may be related to medication adherence.

OBJECTIVE

To evaluate a 3-part intervention (automated telephone reminder calls to refill prescriptions, picture prescription card, and clear health communication training for pharmacists) intended to increase refill adherence through attention to health literacy.

METHODS

Three pharmacies that serve a primarily indigent, minority population served as the intervention sites, and one pharmacy served as the control site. To evaluate the impact of the 6-month intervention on medication adherence, pharmacy refill data were used to calculate the cumulative medication gap (CMG), in which values close to zero indicate better adherence. The primary measure of treatment effect was a comparison of the change in refill adherence within each group, from baseline to follow-up.

RESULTS

A total of 173 patients were enrolled in the intervention group and 102 patients in the control group. Medication adherence was significantly different between intervention (CMG = 0.25) and control (CMG = 0.18) groups at baseline (p = 0.004). Refill adherence in the intervention group improved slightly during follow-up (CMG = 0.23), while it worsened slightly in the control group (CMG = 0.21), but the change in adherence between intervention and control groups was not significantly different (p = 0.4). Between 80% and 90% of intervention participants indicated that receiving the picture prescription and phone call interventions helped them remember when and how to take their medications and refill their prescriptions. No patient characteristics, including health literacy, were consistently associated with adherence.

CONCLUSIONS

Implementation of a 3-part intervention—automated telephone reminders, picture prescription card, and pharmacist communication skills training—did not significantly improve refill adherence among inner-city patients. Further study should explore whether other aspects of medication management, such as dosing or adverse events, can be improved through these types of interventions, implemented either alone or in combination.
Candida Meningitis Post Gliadel Wafer Placement Successfully Treated with Intrathecal and Intravenous Amphotericin B
Authors: Glick Jorie A , Graham Robert S , Voils Stacy A
Published: December 2009

OBJECTIVE

To report a case of Candida meningitis post Gliadel wafer (polifeprosan 20 with carmustine implant) placement successfully treated with the combination of intrathecal and intravenous amphotericin B.

CASE SUMMARY

A 33-year-old white female with a history of recurrent oligodendroglioma was admitted to the neuroscience intensive care unit with acute mental status changes. Computed tomography of the head demonstrated a cystic dilation of the right frontoparietal tumor resection cavity with Gliadel wafers in place and the presence of a large fluid collection. The cavity was debrided surgically and a ventriculostomy catheter was left in place. Cerebrospinal fluid (CSF) cultures were positive for Candida albicans and methicillin-resistant coagulase-negative Staphylococcus spp. Antiinfective therapy with intrathecal and intravenous amphotericin B as well as flucytosine and vancomycin was started. The patient had subsequent improvement in clinical manifestations, resolution of CSF leukocytosis, and mycologic cure.

DISCUSSION

Candida meningitis occurs primarily in the setting of immunosuppression, intravenous drug abuse and following neurosurgical procedures. Secondary bacterial and fungal infections have been reported following Gliadel wafer placement in patients with brain tumor resection. Caniiia meningitis has traditionally been treated with intravenous amphotericin B with or without oral flucytosine. There have been reports of treatment with intrathecal amphotericin B with variable clinical outcomes.

CONCLUSIONS

This case demonstrates successful treatment of Candida meningitis post Gliadel wafer placement with the combination of intrathecal and intravenous amphotericin B. This treatment modality may provide an effective therapeutic option for other patients with Candida meningitis, especially those unresponsive to intravenous therapy.
Maternal Plasma DNA Analysis with Massively Parallel Sequencing by Ligation for Noninvasive Prenatal Diagnosis of Trisomy 21
Authors: Chiu Rossa WK , Sun Hao , Akolekar Ranjit , Clouser Christopher , Lee Clarence , McKernan Kevin , Zhou Daixing , Nicolaides Kypros H , Lo YM Dennis
Published: December 2009

Background: Noninvasive prenatal diagnosis of trisomy 21 (T21) has recently been shown to be achievable by massively parallel sequencing of maternal plasma on a sequencing-by-synthesis platform. The quantification of several other human chromosomes, including chromosomes 18 and 13, has been shown to be less precise, however, with quantitative biases related to the chromosomal GC content.

Methods: Maternal plasma DNA from 10 euploid and 5 T21 pregnancies was sequenced with a sequencing-by-ligation approach. We calculated the genomic representations (GRs) of sequenced reads from each chromosome and their associated measurement CVs and compared the GRs of chromosome 21 (chr21) for the euploid and T21 pregnancies.

Results: We obtained a median of 12 × 106 unique reads (21% of the total reads) per sample. The GRs deviated from those expected for some chromosomes but in a manner different from that previously reported for the sequencing-by-synthesis approach. Measurements of the GRs for chromosomes 18 and 13 were less precise than for chr21. z Scores of the GR of chr21 were increased in the T21 pregnancies, compared with the euploid pregnancies.

Conclusions: Massively parallel sequencing-by-ligation of maternal plasma DNA was effective in identifying T21 fetuses noninvasively. The quantitative biases observed among the GRs of certain chromosomes were more likely based on analytical factors than biological factors. Further research is needed to enhance the precision for measuring for the representations of chromosomes 18 and 13.
β-Catenin as a multilayer modulator of zonal cytochrome P450 expression in mouse liver
Authors: Braeuning Albert , Schwarz Michael
Published: December 2009

The liver is the major organ for metabolism of drugs and other xenobiotics. Expression of many drug-metabolizing enzymes is not equally distributed throughout the liver: under normal conditions, many of them, including the most relevant members of the cytochrome P450 superfamily, are exclusively expressed in a hepatocyte subpopulation located near branches of the efferent central vein. Activation of different ligand-dependent transcription factors by exogenous compounds stimulates high expression of certain cytochrome P450 isoforms. This process also occurs preferentially in perivenous hepatocytes. The mechanisms, however, which determine the zone-specificity of basal and xenobiotic-induced expression of cytochrome P450 enzymes, have remained largely unknown for decades. Very recently, signaling through the Wnt/β-catenin pathway has been implicated in the regulation of zonal gene expression in mouse liver. In this review, current knowledge of cytochrome P450 regulation by β-catenin-dependent transcription is summarized and underlying molecular mechanisms are discussed.
The epimerase activity of anthocyanidin reductase from Vitis vinifera and its regiospecific hydride transfers
Authors: Gargouri Mahmoud , Chaudière Jean , Manigand Claude , Maugé Chloé , Bathany Katell , Schmitter Jean-Marie , Gallois Bernard
Published: December 2009

Anthocyanidin reductase (ANR) from Vitis vinifera catalyzes an NADPH-dependent double reduction of anthocyanidins producing a mixture of (2S,3R)- and (2S,3S)-flavan-3-ols. At pH 7.5 and 30°C, the first hydride transfer to anthocyanidin is irreversible, and no intermediate is released during catalysis. ANR reverse activity was assessed in the presence of excess NADP+. Analysis of products by reverse phase and chiral phase HPLC demonstrates that ANR acts as a flavan-3-ol C3-epimerase under such conditions, but this is only observed with 2R-flavan-3-ols, not with 2S-flavan-3-ols produced by the enzyme in the forward reaction. In the presence of deuterated coenzyme 4S-NADPD, ANR transforms anthocyanidins into dideuterated flavan-3-ols. The regiospecificity of deuterium incorporation into catechin and afzelechin – derived from cyanidin and pelargonidin, respectively – was analyzed by liquid chromatography coupled with electro- spray ionization-tandem mass spectrometry (LC/ESI-MS/MS), and it was found that deuterium was always incorporated at C2 and C4. We conclude that C3-epimerization should be achieved by tautomerization between the two hydride transfers and that this produces a quinone methide intermediate which serves as C4 target of the second hydride transfer, thereby avoiding any stereospecific modification of carbon 3. The inversion of C2 stereochemistry required for ‘reverse epimerization’ suggests that the 2S configuration induces an irreversible product dissociation.
Peptides from the Mycobacterium tuberculosis Rv1980c protein involved in human cell infection: insights into new synthetic subunit vaccine candidates
Authors: Rodríguez Diana , Vizcaíno Carolina , Ocampo Marisol , Curtidor Hernando , Pinto Marta , Elkin Patarroyo Manuel , Alfonso Patarroyo Manuel
Published: December 2009

Mycobacterium tuberculosis infection continues to be a major cause of morbidity and mortality throughout the world. The vast complexity of the intracellular pathogen M. tuberculosis and the diverse mechanisms by which it can invade host cells highlight the importance of developing a fully protective vaccine. Our vaccine development strategy consists of including fragments from multiple mycobacterial proteins involved in cell invasion. The aim of this study was to identify high activity binding peptides (HABPs) in the immunogenic protein Rv1980c from M. tuberculosis H37Rv with the ability to inhibit mycobacterial invasion into U937 monocyte-derived macrophages and A549 cells. The presence and transcription of the Rv1980c gene was assessed in members belonging to the M. tuberculosis complex and other nontuberculous mycobacteria by PCR and RT-PCR, respectively. Cell surface localization was confirmed by immuno-electron microscopy. Three peptides binding with high activity to U937 cells and one to A549 cells were identified. HABPs 31100, 31101, and 31107 inhibited invasion of M. tuberculosis into A549 and U937 cells and therefore could be promising candidates for the design of a subunit-based antituberculous vaccine.
Signal transduction in CHO cells stably transfected with domain-selective forms of murine ACE
Authors: Sun Xiaoou , Rentzsch Brit , Gong Maolian , Eichhorst Jenny , Pankow Kristin , Papsdorf Gisela , Maul Björn , Bader Michael , Siems Wolf-Eberhard
Published: December 2009

Membrane-bound human angiotensin-converting enzyme (ACE) has been reported to initiate intracellular signaling after interaction with substrates or inhibitors. Somatic ACE is known to contain two distinct, extracellular catalytic centers. We analyzed the signal transduction mechanisms in cells transfected with different forms of murine ACE (mACE) and investigated whether the two domains are similarly involved in these processes. For this purpose, CHO cells were stably transfected with mACE or with its domain-selective mutants. In addition to these modified cellular models, human umbilical vein endothelial cells were used in this study. Signal transduction molecules such as JNK and c-Jun were analyzed after activation of cells with several ACE substrates and inhibitors. ACE-targeting compounds such as substrates, inhibitors, or even the ACE product angiotensin-II induce in mACE-expressing cells a signal transduction response. These processes are also evoked by partially inactivated forms of mACE and finally result in an enhanced cyclooxygenase-2 transcription. Surprisingly, the membrane-bound ACE activity is also influenced by ACE-targeted interventions. Our data suggest that the two catalytic domains of mACE do not function independently but that the signal transduction is influenced by negative cooperativity of the two catalytic domains. This study underlines that ACE indeed has receptor-like properties which occur in a species-specific manner.
Ubiquitin ligase complexes: from substrate selectivity to conjugational specificity
Authors: Nagy Vanja , Dikic Ivan
Published: December 2009

Localization, activity and lifespan of a protein are signaled by a small, 8 kDa protein, ubiquitin (Ub). Ub conjugation is a post-translational modification orchestrated by the sequential action of activating (E1), conjugating (E2), and ligating (E3) enzymes. Although a simple combination of an E2 and an E3 enzyme can be sufficient for an active complex, in other cases ubiquitination can occur in the context of large multimeric complexes with enhanced molecular abilities. Here, we review several Ub ligase complexes to highlight strategies governing conjugational specificity, the gained adaptability in substrate specificity, and modulatory flexibility encoded in regulatory components of these diverse multimers.
The first successful adult right-lobe living donor liver transplantation in Hungary
Authors: Máthé Zoltán , Kóbori László , Görög Dénes , Fehérvári Imre , Nemes Balázs , Gerlei Zsuzsa , Doros Attila , Németh Andrea , Mándli Tamás , Fazakas János , Járay Jenő
Published: December 2009

A világszerte fennálló szervdonorhiány csökkentésének egyik lehetősége az élő donoros májtranszplantáció. A szerzők beszámolnak a Magyarországon először végzett felnőttkori élő donoros májtranszplantációval szerzett tapasztalataikról. Az átültetés testvérek között történt, 2007. november 19-én. A 33 éves egészséges férfi donor májának jobb lebenye (V–VIII. szegmentum) került eltávolításra és beültetésre az autoimmun hepatitis talaján kialakult cirrhosisban szenvedő, egy éve májtranszplantációs várólistán levő, 23 éves nőbetegbe. A jobb májlebeny beültetése saját hepatectomia után orthotopicus helyzetben történt. A májfunkció gyorsan javult a transzplantációt követően. A donort szövődménymentes posztoperatív szak után, stabil májfunkciós paraméterekkel, a 10. napon otthonába bocsátottuk. Dolgozik, aktív életet él, a kontrollvizsgálatok a máj jelentős regenerációját mutatták. A recipiens két évvel a májátültetés után, kompenzált májfunkcióval szintén aktív életet él és rendszeres ellenőrzés alatt áll. A felnőttkori élő donoros májtranszplantáció előnye a lerövidíthető várakozási idő és a tervezhető műtét. Az eljárás a donor biztonságának maximális előtérbe helyezésével, jól szelektált esetekben, alkalmas lehet a szervhiány csökkentésére.
Lack of Effect of Moderate Hepatic Impairment on the Pharmacokinetics of Telavancin
Authors: Goldberg Michael R. , Wong Shekman L. , Shaw Jeng‐Pyng , Kitt Michael M. , Barriere Steven L.
Published: December 2009

Study Objective. To evaluate the pharmacokinetics of the lipoglycopeptide antibiotic, telavancin, in patients with moderate hepatic impairment compared with healthy controls.

Design. Phase I, open‐label, single‐dose, matched‐control, pilot study.

Setting. Clinical research unit.

Participants. Eight adults with moderate hepatic impairment (Child‐Pugh class B) and eight age‐, sex‐, and weight‐matched healthy control subjects.

Intervention. All participants received a single 1‐hour intravenous infusion of telavancin 10 mg/kg.

Measurements and Main Results. Plasma samples were collected for pharmacokinetic analysis before the infusion and 1, 2, 4, 6, 8, 12, 24, 36, 48, and 72 hours after the start of the infusion. Concentrations of telavancin and the most prevalent of several minor hydroxylated metabolites, THRX‐651540, were assayed with a validated liquid chromatography‐tandem mass spectrometry technique. Telavancin binding to plasma proteins was determined in a preinfusion sample by using equilibrium dialysis. Pharmacokinetic parameters for telavancin and THRX‐651540 were generally similar between the hepatic impairment and control groups. The mean maximum plasma concentration was 21% lower in patients with hepatic impairment than in controls, which was a statistically (analysis of variance, p<0.05), but not clinically, significant difference. There were no other statistically significant between‐group differences. Adverse events were few and mild.

Conclusion. No apparent differences were observed in the pharmacokinetic disposition of telavancin in patients with hepatic impairment compared with healthy controls in this pilot study. Thus, adjustment of the standard telavancin dosage regimen does not appear to be required in patients with mild‐to‐moderate hepatic impairment.
Implementation of Real-time Gas-lift Optimization in Dubai Offshore Fields
Authors: Shnaib Fathi , Nadar Manickam S. , McAlonan Nick
Published: December 2009

Dubai Petroleum (DP) has recently deployed software interface systems to perform real-time optimization of gas lifted wells offshore. Prior to this, gas lift optimization was initiated manually and was done four times a year. This paper presents the various aspects of the real-time optimization project and the benefits that are coming out of the project.

The real-time optimization (RTO) is a giant step forward as it helps optimize the asset more frequently. This also makes it possible to identify under-performing wells as and when problems develop. In the past this often took several days, in an offshore environment with manpower and logistics constraints.

The benefits of the RTO system would include the following: As the RTO interface feeds the latest well data into the well models held in a live server, the optimization system estimates the expected production from the wells and automatically identifies wells that are sub-optimal in their performance. The system flags those wells for immediate attention.The well models get automatically calibrated whenever a new production test becomes available. The result of the well model calibration (success or failure) is communicated with details as required.The wells will be optimized more frequently, and with the less use of engineering manpower.Using the real-time optimization systems the daily production from the asset can be accurately predicted. Integrating with bulk metering systems, the production can be back allocated to specific wells and the source of downtime / loss identified.By linking the RTO system to corporate KPI's e.g. targets (or capacities) engineers and managers can at a glance check the performance of the asset againt key production targets and spot possible optimization opportunities. They can then drill down into individual wells for detailed analysis.Some level of reservoir monitoring can be achieved by using the allocated production and injection to calculate Voidage Reservoir Ratio over time and also look at cumulative injection and production and the net offtake in the reservoir.

Real-time optimization systems add significant value in large complex gas-lift operating systems. The available gas compression capacity often changes due to equipment related problems, maintenance activities and ambient conditions. It has been proven that for minor system upsets it is more efficient to redistribute the available lift gas rather than shutting-in wells. The real-time optimization system provides the best way to manage the field with the available lift gas at any point in time. As the system calculates the production from the asset using the live data and recently calibrated asset models, the production back allocation is more accurate and reliable.
First Worldwide Application of Fiber Optic Enabled Coiled Tubing with Multilateral Tool for Accessing and Stimulating a Trilateral Oil Producer, Saudi Arabia
Authors: Al-Zain Ahmed , Said Rifat , Gamber Salman , Al-Driweesh Saad , Al-Shahrani Khzam , Jacobsen Jan
Published: December 2009

Since the advent of horizontal technology, new wells have been drilled with thousands of feet of horizontal section to expose large reservoir areas. The advancement of drilling technology also allows drilling more complex wells, such as multilaterals for maximum reservoir contact (MRC). These complex wells impose great challenges with respect to well accessibility for rigless well interventions. One of the initial well interventions, which follow drilling completion, is acid stimulation to remove formation damage.

On the other hand, the recent advancement of coiled tubing (CT) enables rigless interventions of complex wells while acquiring real time downhole measurements. The fiber optic enabled coiled tubing (FOCT) provides combined services of data acquiring and running other CT tools required for well treatments. The fiber optic telemetry system consists of a pump-through bottom-hole assembly (BHA) with a casing collar locator (CCL), pressure and temperature sensors, optical fibers inside CT, and a surface readout unit. By the virtue of the optical fiber, distributed measurements are also viable options to obtain temperature profiles. The temperature surveys allow evaluating flow distribution through temperature responses, thereby optimizing acid stimulation.

A multilateral tool (MLT) using an indexing flow activated bent sub allows locating and accessing the laterals and stimulating them. The CCL readings via the FOCT provide a real time confirmation of accessing laterals.

This paper highlights the first worldwide CT application of combining the fiber optic telemetry system for acquiring downhole data on real time, and a multilateral tool for accessing and stimulating a trilateral oil producer in a major carbonate reservoir in Saudi Arabia. This combination has resulted in a successful optimized acid stimulation of all three laterals. This paper also discusses in detail the job execution challenges, lessons learned, and experience gained to optimize similar future jobs.
Effect of Surfactant Addition, Temperature, and Solvent conditions on Functional Microgels for Enhanced Oil recovery Applications
Authors: Al-manasir Nodar , Kjøniksen Anna-Lena , Zhu Kaizheng , Nyström Bo
Published: December 2009

Interactions between a chemically cross-linked poly(N-isopropylacrylamide) (PNIPAAM) microgel and the anionic surfactant sodium dodecyl sulfate (SDS) have been investigated by dynamic light scattering (DLS) and turbidimetry in both a buffer system (pH = 7) with an ionic strength of 0.05 M and water. Both the turbidity and DLS measurements revealed significant polymer-surfactant interactions between PNIPAAM and SDS in the buffer system, whereas in the absence of buffer only the highest SDS concentration clearly deviates from what is observed in the absence of surfactant. The DLS results show that the particles shrink with increasing temperature at all conditions; a macroscopic phase separation is approached at higher temperatures for the microgels without or with low SDS concentration in the buffer system. Mixtures of microgels and surfactants may be promising for enhanced oil recovery applications.
Mobile Production Testing: A Highly Accurate and Flexible Solution
Authors: Cadalen Sebastien , Chazal Damien , David Pierre-Yves , Elie Nicolas , Jolivet Guillaume
Published: December 2009

The use of multiphase flow meters (MPFM) for surface well production metering without separation of the phases is now an established practice in the oil industry and is a key element for production allocation, well performance optimization and reservoir monitoring.

In parallel, the demand for mobile testing with multiphase flow meters service is increasing and the challenges to face are numerous due to the wide range of wells flowrates, fluid characteristics (from heavy oil to gas-rich applications) and flow conditions (emulsions, foam, slug…).

Based on years of experience in field surveillance and multiphase flow metering, a new multiphase flow meter, designed to cover accurately both multiphase and wet gas flow conditions has been developped. The technology choices rely on robust and proven measurement principles used in multiphase flows while further developments have secured the performances under challenging conditions.

This paper describes the development of the solutions that allow this MPFM to achieve high performance in all flow conditions and presents the results obtained in various flow loops in the past two years.

Results confirm the accuracy of the technology under multiphase and wet gas conditions that will address a request of oil and gas producers for high performance metering systems.

This technology has been implemented in a compact and rugged mobile testing unit designed for mobile production testing. It includes two independent measuring sections (2" and 4") to cover low to high flow rate conditions. This feature, associated with the high performance of the measurement in multiphase and wet gas, provides a versatile service solution well-adapted to the various fluid and flow conditions encountered in oil & gas fields.
Selection of Proper Criteria in Flow Behavior Characterization of Low Tension Polymer Flooding in Heavy Oil Reservoirs
Authors: Jamaloei Benyamin Yadali , Kharrat Riyaz , Ahmadloo Farid
Published: December 2009

Applying a suitable enhanced oil recovery method to heavy oil reservoirs is still controversial. Low Tension Polymer Flooding (LTPF) can be considered when thermal and solvent-based methods are not feasible due to technical difficulties and/or economical/environmental constrains. Performance of LTPF, which uses cost-effective surfactant with dilute concentrations within the injected polymer solution, is noticeably far superior to that of alkali-surfactant flooding which suffers from sever viscous instability and/or weak in-situ surfactant generation due to inappropriate acid number of some heavy oils.

To properly characterize the microscopic and macroscopic flow behavior of LTPF in heavy oil displacement, the interplay between viscous, capillary, and gravitational forces should be identified by utilizing bond and capillary numbers. Unlike bond number, the capillary number has been defined in several forms by researchers many of which are not equivalent. An appropriate definition of the capillary number should be correctly selected and employed–according to the interest in scale and fluid-flow behavior–so as to quantify the impacts of selected capillary number on the hydrodynamic instability, relative permeability shifts, and phase trapping and bypassing in LTPF in heavy oil displacement.

In this study, the capillary number definitions (i.e., pore-scale, Newtonian-fluid, and apparent capillary numbers) were evaluated to determine an appropriate capillary number definition to quantify the LTPF in heavy oil displacement by employing physical modeling and numerical simulation. Moreover, the effects of pore size distribution and injection flowrate on above-mentioned three different capillary number definitions and their sensitivity to the change in those parameters were examined. It was inferred that the sensitivity of change in the pore-scale capillary number is appropriate to evaluate the phase trapping and bypassing whereas the apparent capillary number should be used to characterize the macroscopic behavior (e.g., relative permeability shifts, hydrodynamic instability, and recovery versus capillary number curves) of LTPF. The effects of the pore size distribution and injection flowrate on phase trapping and bypassing, which were rendered, can be considered as a practical guide to build a robust trapping model which is the key to properly simulate and optimize the entire LTPF in lab and field scales.
Deep Marrat Carbonate Reservoir Development & Production Challenges in Dharif Field of West Kuwait
Authors: Dakshinamurthy Natarajan , Salaam Tareq Abdul , Verma Naveen K , Al-Khamees Waleed
Published: December 2009

The Marrat reservoir in Dharif field is a deep, sour, high pressure oil accumulation of Jurassic age containing light under-saturated oil of 36-38° API. The carbonate reservoir has a porosity range of 10-20% with permeability of 1-10 md. The field was put on production in 1989 through one well. Subsequently, 10 wells were added gradually developing the field. As of date, the field has produced about 12.5% of oil in place, lowering the reservoir pressure from 10,525 to 7,000 psi.

At present, oil production from the field is about 13,500 bbls/day. Due to low permeability, some wells produce with high drawdown approaching asphaltene onset pressure (AOP), estimated at 3,400 psi. This causes Asphaltene deposition in the tubing that requires cleaning to maintain the production level. The major challenges now are to produce the wells above AOP to avoid asphaltene precipitation in the wells or reservoir while sustaining the production level and maximizing recovery.

Hence, Full Field Model (FFM) for simulation studies was constructed and history-matched. Under depletion case, where the wells produce above AOP, field produced about 24% STOIIP. The water injection case shows significant increase in recovery to 40% STOIIP. Since no prior experience of water injection is available for such tight deep carbonate reservoirs in West Kuwait Fields, several key studies such as a) RCAL & SCAL b) Core flood Study c) Water Compatibility & Scale Prediction modeling d) Injectivity test, were carried out to address water injection feasibility.

The present paper shares the results of above studies which indicate that water injection is a viable option to maintain the reservoir pressure to produce the wells above AOP as well as to maximize recovery. Pilot water injection is planned through one well for which the area has been optimized using FFM. At present Pilot Water injector and source wells have been drilled and injection will be initiated with commissioning of surface facilities
New Approaches for Analyzing Transient Pressure from Oil And Water Two-Phase Flowing Reservoir
Authors: Zheng Shiyi , Xu Wenbin
Published: December 2009

Theory and practice in the past on well testing reservoir with multi-phase flow such as oil and water system achieved limited success. Methods include multi-phase pseudo-pressure, pressure squared and total compressibility, total mobility, i.e. Perrine- Martin (P-M) method. As recognized by the industry, multi-phase pseudo-pressure approach was flawed, while only P-M method is applicable in strictly oil-water system.

Multi-phase flow well testing research subject attracted the oil industry's interest again is purely due to the onset of permanent down hole gauge (PDG), which made long term multi-phase flow transient pressure data at every stage available.

This paper explored in depth the problem of well testing in oil-water two-phase flowing system further. Four types of flow mechanisms were modeled and studies were conducted through numerical well testing. These are: (1) dispersed flow with uniform saturation; (2) dispersed flow with non-uniform saturation; (3) oil-water segregated flow and (4) oil reservoir with aquifer-support. Case (1) is an ideal case, where oil and water assumed to be fully dispersed across the entire reservoir thickness. But in practice, water saturation is non-uniform in reservoir, so it is in fact the case (2). Case (3), segregated flow occurs when gravity forces are dominating, leading to complete segregation of oil overlying water. Such situation can also be due to early water breakthrough in layered reservoir with high permeability formation. Case (4) characterizes the situation where the well is completed in part of the formation away from the water formation in order to prevent water coning. This will create a different flow problem due to spherical flow.

Transient data were generated through numerical experiments for every defined flow mechanisms above. Considering relative permeability curves, traditional P-M method was fully examined and modified to obtain the true reservoir properties such as absolute permeability in these situations. Following the numerical well testing procedures, interpretation issues due to the difference between the theory and practice were addressed much more properly and clear.
Assessment of Awareness of Disability Measures among Persons with Acquired Brain Injury
Authors: Anderson Rhona L. , Doble Susan E. , Merritt Brenda K. , Kottorp Anders
Published: December 2009

Background. Limited self-awareness of disabilities can compromise individuals' occupational performance. Purpose. The Assessment of Awareness of Disability (AAD) provides occupational therapists with a standardized methodology for measuring clients' self-awareness when performing activities of daily living (ADL). This is the first study that formally examines the stability of the AAD measures. Methods. The AAD was administered twice to 15 participants with acquired brain injury (ABI) within one or two days. One participant's data were excluded because significant changes in his ADL process abilities were detected. Two criteria were used to examine the stability of the remaining 14 participants' AAD measures: standardized diference Z-scores and a difference of 0.65 logits. Findings. All 14 participants' AAD measures were stable on the basis of their Z-scores; 13 participants' measures were stable based on the 0.65 logit difference. Implications. Occupational therapists can have confidence that the AAD generates stable measures when administered to adults with ABI.
Does Aversive Conditioning Reduce Human—Black Bear Conflict?
Authors: MAZUR RACHEL L.
Published: December 2009

ABSTRACT Aversive conditioning (AC) has the potential to temporarily reduce conflicts between humans and black bears (Ursus americanus). From 2002 to 2005, I evaluated the effectiveness of projectiles with varying impact intensities, pepper spray, and chasing on approximately 150 bears in Sequoia National Park. Aversive conditioning was successful in keeping bears that were not food‐conditioned from becoming food‐conditioned. For the bears that were already food‐conditioned, 17 of 29 bears subjected to AC abandoned unwanted behaviors, 6 required continual treatments, and 6 were killed or relocated. Success with food‐conditioned bears was highest when AC was applied soon after bears obtained human food. Aversive conditioning was less successful on yearlings than adults. Rubber slugs were slightly more effective than lower impact projectiles.
Short‐Term Responses of Red Squirrels to Prescribed Burning in the Interior Pacific Northwest, USA
Authors: RUSSELL ROBIN E. , LEHMKUHL JOHN F. , BUCKLAND STEPHEN T. , SAAB VICTORIA A.
Published: December 2009

ABSTRACT We quantified changes in density of red squirrels (Tamiasciurus hudsonicus) in response to prescribed fire in mixed coniferous forests of Idaho and Washington, USA, using a Before‐After‐Control‐Impact design. We found no evidence that low‐severity prescribed fires affected density of red squirrels; we estimated the change in red squirrel densities due to prescribed fire as −0.15 squirrels/ha (95% CI = −0.405–0.105). Squirrel density did, however, increase with increasing live tree density, shrub cover, and density of large downed logs, and varied across years and states. These results indicate that land managers implementing prescribed fire treatments to reduce fuel loads on public lands can reduce the impacts of fire on squirrel populations by formulating prescriptions to retain large live trees and large downed logs.
Long‐Term Persistence of Spent Lead Shot in Tundra Wetlands
Authors: FLINT PAUL L. , SCHAMBER JASON L.
Published: December 2009

ABSTRACT  We seeded experimental plots with number 4 lead pellets and sampled these plots for 10 years to assess the settlement rate of pellets in tundra wetland types commonly used by foraging waterfowl. After 10 years, about 10% of pellets remained within 6 cm of the surface, but >50% remained within 10 cm. We predict that spent lead pellets will eventually become unavailable to waterfowl; however, it will likely require >25 years for all pellets to exceed depths at which waterfowl species may forage.
Evidence of a Minimum Patch Size Threshold of Reproductive Success in an Endangered Songbird
Authors: BUTCHER JERROD A. , MORRISON MICHAEL L. , RANSOM DEAN , SLACK R. DOUGLAS , WILKINS R. NEAL
Published: December 2009

ABSTRACT  That area‐sensitive songbirds breed only in relatively large patches suggests that there may be a minimum patch size threshold in which they will breed, even when controlling for the total amount of habitat in the landscape. We searched for minimum patch size thresholds of presence, territory establishment by males, pairing success, and reproductive success for 2 migratory songbirds that differed in sensitivity to patch size: golden‐cheeked warblers (Dendroica chrysoparia) and white‐eyed vireos (Vireo griseus). We assessed 2 potential limiting factors: brown‐headed cowbird (Molothrus ater) parasitism and arthropod biomass (food resource). We determined whether either factor was related to patch size and compared measurements of each above and below the observed thresholds. We monitored 24 golden‐cheeked warbler and 47 white‐eyed vireo territories in 12 patches. We found evidence of a minimum patch size threshold (between 15.0 ha and 20.1 ha) of reproductive success for golden‐cheeked warblers, but not for white‐eyed vireos. We found no minimum patch size thresholds for presence, territory establishment by males, or pair formation for either species. Conservation practices based on thresholds of presence, territory establishment, or pair formation might not address issues of reproduction for golden‐cheeked warblers. We failed to find evidence that cowbird parasitism or arthropod biomass were limiting factors. The ability to identify patch size thresholds of reproductive success for target species could be useful in conservation and management for setting goals for retention and restoration of target species’ habitat patch size.
Effects of Local and Landscape Variables on Wetland Bird Habitat Use During Migration Through the Rainwater Basin
Authors: WEBB ELISABETH B. , SMITH LOREN M. , VRTISKA MARK P. , LAGRANGE THEODORE G.
Published: December 2009

ABSTRACT  Staging areas and migratory stopovers of wetland birds can function as geographic bottlenecks; common dependence among migratory wetland bird species on these sites has major implications for wetland conservation. Although 90% of playa wetlands in the Rainwater Basin (RWB) region of Nebraska, USA, have been destroyed, the area still provides essential stopover habitat for up to 10 million waterfowl each spring. Our objectives were to determine local (within wetland and immediate watershed) and landscape‐scale factors influencing wetland bird abundance and species richness during spring migration at RWB playas. We surveyed 36–40 playas twice weekly in the RWB and observed approximately 1.6 million individual migratory wetland birds representing 72 species during spring migrations 2002–2004. We tested a priori hypotheses about whether local and landscape variables influenced overall species richness and abundance of geese, dabbling ducks, diving ducks, and shorebirds. Wetland area had a positive influence on goose abundance in all years, whereas percent emergent vegetation and hunting pressure had negative influences. Models predicting dabbling duck abundance differed among years; however, individual wetland area and area of semipermanent wetlands within 10 km of the study wetland consistently had a positive influence on dabbling duck abundance. Percent emergent vegetation also was a positive predictor of dabbling duck abundance in all years, indicating that wetlands with intermediate (50%) vegetation coverage have the greatest dabbling duck abundance. Shorebird abundance was positively influenced by wetland area and number of wetlands within 10 km and negatively influenced by water depth. Wetland area, water depth, and area of wetlands within 10 km were all equally important in models predicting overall species richness. Total species richness was positively influenced by wetland area and negatively influenced by water depth and area of semipermanent wetlands within 10 km. Avian species richness also was greatest in wetlands with intermediate vegetation coverage. Restoring playa hydrology should promote intermediate percent cover of emergent vegetation, which will increase use by dabbling ducks and shorebirds, and decrease snow goose (Chen caerulescens) use of these wetlands. We observed a reduction in dabbling duck abundance on wetlands open to spring snow goose hunting and recommend further investigation of the effects of this conservation order on nontarget species. Our results indicate that wildlife managers at migration stopover areas should conserve wetlands in complexes to meet the continuing and future habitat requirements of migratory birds, especially dabbling ducks, during spring migration.
Space and Habitat Use by a Red Wolf Pack and Their Pups During Pup‐Rearing
Authors: HINTON JOSEPH W. , CHAMBERLAIN MICHAEL J.
Published: December 2009

ABSTRACT  During summer 2005, we evaluated space and habitat use by red wolves (Canis rufus) during pup‐rearing. Home‐range sizes for red wolves (3 ad, 3 juv, and 4 pups) varied from 3.48 km2 to 12.24 km2. Red wolves selected agricultural fields over adjacent forested areas and used less space during pup‐rearing than we expected based on prior knowledge of the species. Attending pack members rarely left pups alone, pack members shared pup‐rearing duties, and male red wolves appeared to play a significant role in pup‐rearing.
Nest Site Selection by Western Gray Squirrels at Their Northern Range Terminus
Authors: GREGORY SARA C. , HAEGEN W. MATTHEW VANDER , CHANG WAN YING , WEST STEPHEN D.
Published: December 2009

ABSTRACT  The western gray squirrel (Sciurus griseus) in Washington, USA, is limited to 3 disjunct areas and is a state threatened species. Information is lacking for the North Cascades population, which is the northernmost population for the species. Squirrels in this population exist without oaks (Quercus spp.) that provide forage and cavities for maternal nests elsewhere in their range. During May 2003 to August 2005, we studied selection of nest sites and nest trees by 18 radiocollared squirrels in Okanogan County, Washington. Without oak cavities, females reared their young in dreys. General nest‐tree characteristics were similar to characteristics of western gray squirrel nest trees in Southeastern Cascades: relatively tall ponderosa pines (Pinus ponderosa) ≥ 40 cm diameter at breast height. Results from conditional logistic models determined that the odds of a squirrel selecting a tree for nesting increased with greater diameter at breast height and with infection by dwarf mistletoe (Arceuthobium spp.). Nest sites with high selection probability by squirrels had greater basal area and number of tree species than available unselected sites. Retention of forest patches that include a mix of conifer species or conifer and deciduous trees and moderate to high basal area could promote nesting opportunities, connectivity for arboreal travel, as well as abundance and diversity of hypogeous fungi. Experiments to test the efficacy of retaining untreated patches of varying size (including trees infected with mistletoe) on nesting by western gray squirrels within stands managed for fire suppression and forest health would provide important information about the effects of forest fuel management on arboreal wildlife.
Should the Regulator or the Market Decide When to Reduce Greenhouse Gas Emissions?
Authors: Friedman Lee S. , Deason Jeff
Published: December 2009

Lee Friedman and Jeff Deason of UC Berkeley propose a plan to handle a variety of timing issues too often ignored in regulatory programs to reduce greenhouse gas emissions.