bluuebunny/crossref_metadata_2025 huggingface dataset:
Field Experience with an Active Stick-Slip Prevention System
Authors: Nessjøen Pål Jacob , Kyllingstad Åge , D'Ambrosio Piero , Fonseca Isaac S. , Garcia Alexis , Levy Bruno
Published: March 2011

Stick-slip oscillations are self-sustained and periodic twist and torque oscillations of a rotating drill string, characterized by large and harmful variations of the downhole rotation speed. This paper is a field evaluation of an active stick-slip prevention system.

The evaluated system is active with smart control of the top drive, meaning the top drive speed is varied in a way that dampens stick-slip oscillations. It is software based, in many cases it requires no extra instrumentation and can be implemented on virtually any types and brands of top drives.

The paper includes field test results, both from ordinary tests with surface data on top drive speed and torque, and from special tests including downhole measurements. The field data verified existence of the expected 2nd mode stick-slip in longer strings and proved that the system is able to reduce the downhole speed variations. Therefore a general conclusion is that the active stick-slip prevention system significantly lowers the critical rotation speed below which stick-slip oscillations persist. Simultaneous surface and downhole measurements indicate that the reduction of stick-slip oscillations improved drilling performance and the rate of penetration (ROP).

The positive field test results are good news to the drilling industry that has struggled for a long time with harmful stick- slip oscillations, causing premature tool failures, excessive bit wear and poor drilling rate. Installation and use of an active stick-slip prevention system is therefore a very cost effective solution to a long outstanding problem.
Development of an Innovative Model-Based Stick/Slip Control System
Authors: Rudat Jens , Dashevskiy Dmitriy
Published: March 2011

Stick/slip is a severe type of torsional drillstring oscillation that affects the efficiency of the drilling process and can cause bit damage as well as drillstring failure. Different approaches to mitigate stick/slip oscillations are used in the field, ranging from procedures for optimizing drilling parameters, to passive downhole damping devices, and active surface controllers. To improve performance, some of these systems use mathematical models of the rotary system. Since the drilling process is subject to permanent changes, model-based control systems can only perform adequately when constantly updated with the actual conditions. To date, surface data has been used for this, but some key drilling process characteristics can only be identified with downhole data.

This paper presents an innovative model-based stick/slip control system. It is based on a model of the drilling process that predicts the intensity of downhole vibration with respect to drilling parameters. Using downhole measurements, the model is adapted to the actual drilling process and employed to find optimal drilling parameters. To overcome the limited bandwidth of the typically used mud-pulse telemetry systems, models are identified downhole in the dynamics measurement tool.

The paper presents field tests performed to evaluate the stick/slip control system and the investigation of how model parameters can be identified from measurements as well as how well the identified models represent the drilling process. Results show that this model can be used to predict the intensity of torsional oscillations and determine optimal drilling parameter values.

The presented stick/slip control system can provide quantitative recommendations on changing drilling control parameters to mitigate stick/slip and can be used in an automated mode by directly connecting to the rig control system for monitoring drilling conditions and adjusting drilling parameters. Proper handling of downhole vibrations can significantly increase reliability.
Passive Inflow Control Devices and Swellable Packers Control Water Production in Fractured Carbonate Reservoir: A Comparison with Slotted Liner Completions
Authors: Youl Kim Sam , Harkomoyo _ , Suhana Widayat , Regulacion Rhandy , Jorgensen Thomas
Published: March 2011

Many applications for Inflow Control Devices (ICDs) are designed to delay water breakthrough in new wells and for remediating wells shut-in because of water encroachment. The ICDs for carbonate reservoirs typically are combined with wire-wrapped screen (WWS) strainers on 13-ft basepipe. Many wells also have been compartmentalized with swellable packers. Passive inflow control technology has been used extensively in horizontal wells in the Norwegian section of the North Sea and in the Middle East for approximately a decade. This paper discusses first usage of a new tube-type ICD combined with swellable packers to control water in fractured carbonate reservoirs in Asia. Traditionally, horizontal wells in the Poleng field in East Java, Indonesia were completed with slotted liners and struggled with early water breakthrough and high water-cut production. Since highly productive fractures are thought to be the main conduit for water, and slotted liners do not provide control for fluid inflow to the wellbore, resolving high water cut has challenged offshore production significantly.

To combat these challenges, a new completion strategy using ICDs and swellable packers for both delaying and minimizing water breakthrough has been developed.

Production performance of 5 horizontal wells completed with the ICD/swellable packer concept will be compared to production of 8 wells completed traditionally. This project marks several world firsts in tube-type ICD technology with its first installation in Indonesia.
Achievements and Lessons Learned from a 4-Year Experience of Extended Reach Drilling in offshore Dagang Oilfield, Bohai Basin, China
Authors: Cheng Rongchao , Wang Haige , Zou Lingzhan , Zhou Mingxin , Sha Dong , Liu Chuandu
Published: March 2011

The long-term continuous exploitation makes it increasingly difficult to maintain sustainable hydrocarbon production onshore in Dagang Oilfield. The shelf sea area of Bohai Basin with an average water depth of about 2.5m is identified as the main take-over battlefield, which needs to be developed by extended reach drilling (ERD) due to the lower loading capability of subsea thick silt and the inaccessibility of drilling rigs onshore or offshore. This is one of the major ERD campaigns implemented independently onshore in China.

Favorable achievements have been obtained during the 4-year ERD play. Four extended-reach horizontal wells with the horizontal displacements larger than 4000m have been successfully completed by integrated application of pseudo-catenary trajectory design, casing floating running technology, compound drilling method, real-time ECD monitoring, highly inhibitive drilling fluid, optimized hole cleaning operation and enhanced drag/torque reduction technology. The maximum horizontal displacement to vertical depth ratio reaches 3.92. Many other ERD records have also been made in China onshore, building basic foundations for much larger-scale of application of ERD in Bohai Basin. Meanwhile, many new challenges have also emerged, such as the wellbore instability in highly deviated intervals, inappropriate design and optimization of PDC bit, instable bottom hole assembly (BHA), difficult control on well trajectory for the long angle-holding section, etc. This calls for technical innovations to address problems associated with previous ERD activities.

This paper focuses on the technical achievements as well as the lessons learned from the ERD play in recent years, with its purpose to explain where we are and what to do next for further research and development of ERD technology in China. Helpful case histories and recommendations will also be presented.
Dynamic Aspects Governing Cement Plug Placement in Deepwater Wells
Authors: Aranha P. E. , Miranda C. R. , Magalhães J. V. , Campos G. , Martins A. L. , Braghini A. , Naccache M. F.
Published: March 2011

Plug cementing is still considered to be a critical operation and cases of failure eventually happen. Large annular gap and eccentricity, typical of these operations, are factors which may promote unstable flows resulting in cement slurry contamination. Deepwater conditions enhance chances of free fall, and consequently, low displacement velocities can occur in the annulus.

This article presents a parametric study in the role of rheological properties of fluids (drilling fluid, spacers and cements slurries), string rotation, flow rates (including freefall effects) in the displacement quality of cement plugs. Analyses are based on 2 different simulation tools. Conventional cement pumping softwares define flow rate profiles at annulus entrance, accounting for free fall effects and CFD to simulate the interface propagation and contamination levels.

The main issues addressed by the simulations are:

What are the maximum yield stresses which guarantee that non stagnation regions while circulating the drilling fluid? How to optimize density and rheology hierarchy which minimizes contamination and avoids channeling? What is the role of string rotation on the displacement efficiency?

The compilation of simulation results in useful guidelines and procedures for displacing cement plugs in vertical, inclined and horizontal offshore wells.
Anatomy of the "Best In Class Well": How Operators Have Organised the Benchmarking of their Well Construction and Abandonment Performance
Authors: Rushmore Peter
Published: March 2011

The use of comparative performance data by operators to drive well construction performance improvement is a powerful and proven technique. Offset well data is also used by operators for a range of other applications.

Twelve operators came together in 1989 to organise the sharing of drilling offset data between themselves, in order to remedy the deficiencies experienced in obtaining this data from other sources. This has grown into a global programme with data shared on over 38,000 wells provided by over 200 operating companies in 80 countries (Appendix 1 and 2). As well as the initial drilling study, data are also shared in studies looking at the completions and well abandonment phases.

Every super-major, most of the large and mid-sized international operators, many independents and a number of national oil companies participate in one or more of these studies. It is the aim of the participating operators to grow the programme to ultimately collect data on all hydrocarbon wells constructed globally.

This paper describes why operators have chosen to share comparative performance data amongst themselves, the way in which this is organised and the data itself. It examines the analysis and normalisation tools employed as well as the quality controls in place to ensure data integrity. Operators use the data for benchmarking and other applications, all focused on improving planning and operational performance.
Merging Multilateral and Casing Exit Technologies to Increase Wellbore Junction Reliability by Reducing Rig and Openhole Exposure Times
Authors: Guidry Christopher , Pleasants Charles , Sheehan Joseph
Published: March 2011

This paper will reveal the challenges and benefits of merging casing exit, sealbore diverter, and multilateral casing junction technologies into one system that reduces both rig and openhole exposure times, thereby improving reliability, reducing risk, and providing a more cost-effective solution to meet the client's needs.

Typically, a multilateral junction well is accomplished by completing a casing exit with a conventional whipstock and milling bottomhole assembly (BHA), drilling the openhole, removing the whipstock, installing the sealbore diverter, and then integrating the multilateral casing junction to the sealbore diverter at the casing exit window. Accurate lateral and rotational positioning of the sealbore diverter relative to the casing exit window is required in order to properly land the multilateral junction. In addition, the time lapse between the milling-drilling operation and installation of the multilateral casing junction increases the probability of openhole collapse.

A new system combines the attributes of the whipstock and sealbore diverter into one downhole assembly, which allows the whipstock to be retrieved while leaving the sealbore diverter anchored and properly oriented in the wellbore. This removes lateral and rotational orientation concerns, while also eliminating one trip downhole, thus reducing both rig and openhole exposure times. A new geometry milling BHA was also employed to maximize window length to improve ingress and egress of steerable drilling BHAs.

Extensive qualification testing was performed on a horizontal skid to replicate highly deviated well conditions, and those results will be reviewed. Field trials were completed in the second quarter of 2010. Operational results will be included for discussion.
Case History of Innovative Plug and Abandonment Equipment and Processes for Enhanced Safety and Significant Cost Savings
Authors: Olstad Delaney , McCormick John
Published: March 2011

Traditional rigless plug-and-abandonment (P&A) operations are time consuming and rely upon methods that are potentially detrimental to personnel, the environment and the assets involved. With rising standards for personnel safety, increased costs and the delicate nature of working in fragile ecosystems, the development of innovative technologies and the application of resources for well abandonment operations is vital to the oil and gas industry. This paper examines the successful deployment of first-to-market intervention and well abandonment equipment to solve P&A problems in a safe and efficient manner on multiple offshore projects.

The focal point of specialized equipment examined in this paper is the pulling and jacking units (Units) which are being used in offshore operations that include intervention and well abandonment to address hurricane damaged platforms as well as aging wells in the Gulf of Mexico (GoM). These Units are designed to rapidly provide a strong foundation for intervention and well abandonment resources to conduct multiple project tasks. Currently there are two hydraulically actuated pulling and jacking units operating in the GoM market. Despite significant challenges, both of these units have demonstrated an excellent safety record and significant cost savings to the operator.

Unit 1 was commissioned in June 2007 and has operated successfully on multiple platforms with no recordable incidents in its three-and-a-half-year history. Unit 2 is currently on its initial project. Since commencing operations in October 2009, it is 108 days ahead of schedule, which equates to a cost savings of $10.8 million to the operator.

These Units provide a complete, innovative project package and their success, along with the use of decommissioning equipment, has created opportunities for all involved to make enhanced safety and significant cost savings a reality.
New Sampling and Testing-While-Drilling Technology, A Safe, Cost-Effective Alternative
Authors: Proett Mark , Eyuboglu Sami , Wilson Jim , Solbakk Tommy
Published: March 2011

In today's drilling environments and economics oil companies demand focus on all aspects of services delivered by the oil field service companies. Safety and efficiency are paramount with cost considerations following closely behind. Reductions of non-productive time are continuously monitored to evaluate service delivery excellence. All economics are impacted by dead or non productive time associated with failed or damaged equipment, logistical complexities, unplanned events (i.e., weather storms), complex reservoirs and drilling trajectories.

A costly yet extremely critical service for the oil companies is the capture of representative fluid samples from the reservoirs they are drilling. This is done today with formation sampling wireline tools (FSWL) lowered into the wellbore days after the drilling of the formation. The timeliness of this information as well as the additional rig costs associated with the capture of this information can be several days or more in additional time for the sampling operation. In many cases, such as in high angled or horizontal wells, the drill pipe is required to convey the wireline to the formations. In these instances the tools cannot be gravity conveyed, which adds cost and additional risk. Because formation sampling while drilling (FSWD) technology has recently been introduced, significant cost savings are possible because the testing and sampling can be performed during the drilling process. It is the objective of this paper to demonstrate an economic model using field examples to evaluate the cost benefit between using FSWL and FSWD fluid sampling operations acquired in deep water fields. Factors considered are the operating costs for FSWL and FSWD, the probability for fishing, reduction in pumping times associated with lower invasion for FSWD and reducing the operational time in high angel wells and the ability to make changes in well construction.
Low Force Shear Rams: The Future is More
Authors: Springett Frank , Ensley Eric , Yenzer Darrin
Published: March 2011

With the increased usage of stronger and tougher tubulars in today's well construction, the ability to shear in the blowout preventor (BOP) without turning to larger operators is an economic necessity. Existing rigs need ways to drill with the high performance steelavailable today without having to grow the size of the BOP.

This paper will discuss the mechanics of shear and how it applies to V Shear technology of yesterday as well as the current Low Force Shear of today and tomorrow. The Low Force Shear technology provides the technology to extend the capabilities of present day BOPs through major improvements in shear ram design. These shears substantially reduce the forces needed to cut tubulars. Lower forces mean that both stronger and larger diameter tubulars can be managed with the same shear operators, adding value to the existing stack and saving the contractor a major outlay for increased BOP capabilities and corresponding handling equipment upgrades.

Low Force Shear technology is based in the philosophy of final shear area reduction. Getting more of the cross sectional area cut prior to the final shear reduces the forces required in that final shear by leaving a smaller remainder cross sectional area to be cut. By puncturing the tubular first and managing the design of the sheared material (chip management), the Low Force Shear begins effectively cutting material earlier and farther before reaching the final shear section.

As the development of the Low Force Shear is optimized for various diameters, material properties, and cross sectional areas, the opportunities expand to increase the range and variety of items in the well bore that can be cut that were not previously thought possible. This capability would greatly increase the security of the well. The future frontier is "Shearing More".
Managing New Technology Introduction to Provide Maximum Benefit
Authors: Hatch Andy , Shepherd Nicol , Diepeveen Peter , Affleck Grant
Published: March 2011

This paper will address the improvements in well placement and drilling efficiency seen during a start-up project where wired drillpipe was introduced as an enabling technology during the project.

By using multiple strands of new technology, in a controlled, managed fashion, Eon Ruhrgas delivered rate of penetration (ROP) increases of 200% and, at the same time, increased net-to-gross by nearly 100%. The delivery of these new technologies will be reviewed along with the culture of learning and constant improvement fostered by the Eon Ruhrgas. The collaborative atmosphere led to an open environment where all the potential issues, risks, and hazards had been discussed and contingencies made to ensure that delivery would not be compromised.

A case study on the drilling of the first three wells on the Babbage field, where significant new technology advances were introduced on the second and third development wells, will outline, in detail, the improvements in performance observed. In summary, the introduction of wired telemetry drillpipe and the use of a downhole-powered rotary steerable system (RSS) ensured optimum trajectory control, ensuring "sweet" spots were identified and delivered, while maintaining an optimum ROP. By using the increased data-carrying capability of the wired drillpipe, it was possible to provide high quality image data, allowing a better understanding of the downhole environment and ensuring that the stratigraphic control was optimized. The optimization was enhanced by 24-hour operations geological support, continuous dip-picking, and geosteering modelling support onshore but live-linked to the wellsite. By using this knowledge in conjunction with a mud motor power section attached to an RSS, it was possible to deliver a step change in drilling performance through the reservoir.
MPD Application with CBHP Technique in Horizontal Well Drilling for the Development of an HPHT and Sour-Environment Gas Field: A Case History
Authors: Gustioro P. , Idi Yusup A. , Syahriza Ghany R. , Purwanto Arga , Radley David
Published: March 2011

From the effect of global energy demands, many oil industries are forced to search for hydrocarbons in more challenging environments. For example, drilling under high pressure-high temperature (HPHT) conditions has become common practice over the past 15 years, and new technologies are being developed to keep up with the need to drill safely and efficiently, minimize formation damage, and improve the production rate.

The decision to drill two highly deviated and horizontal gas wells in the "S" field located in South Sumatera, Indonesia led to a detailed drilling strategy for managing the HPHT - sour gas environment and the narrow pressure window. Subsurface simulation confirmed that these well designs will provide additional gas recovery compared to existing vertical wells and also extend the plateau time production accordingly. The main challenge was to connect two vertical wells into one horizontal that would contribute to 60% of gas recovery from this structure.

Managed pressure drilling (MPD) was the main option for drilling this well in terms of drilling risk, compared to conventional techniques. The MPD method provides better control over formation damage along the horizontal section. Stimulating deep, hot, sour gas wells can be risky, and the chance of gas recovery is less when conventional drilling practices are used. Therefore, MPD coupled with the constant bottomhole pressure (CBHP) technique was chosen to fulfill the technical requirements.

The initial well production test result shows that the MPD technique succeeded in minimizing drilling-related problems along with minimizing formation skin damage. This allowed the well to meet the proposed production rate targeted by the subsurface team.

This paper describes the planning process for designing MPD HPHT drilling in a sour environment well and includes the implementation results and lessons learned from the drilling process.
Treatment of Oily Wastewater of a Gas Refinery by Electrocoagulation Using Aluminum Electrodes
Authors: Saeedi Mohesn , Khalvati‐Fahlyani Amin
Published: March 2011

Oily wastewaters are the most important discharges of gas refineries from an environmental point‐of‐view. In the present study, treatment of gas refinery oily wastewater by electrocoagulation using aluminum electrodes was investigated. The effects of electrode distance, initial pH, sodium sulfate (Na2SO4) as a supporting electrolyte, polyaluminum chloride dosage as a coagulant aid, and current density on the efficiency of chemical oxygen demand (COD) removal were examined. The results revealed that the COD removal rate increases by applying more current density and polyaluminum chloride and, to a lesser extent, Na2SO4 dosage. The results also showed that 97% COD can be removed at optimum operational conditions. Specific electrical energy consumption could be reduced from 19.48 kWh (kg COD removal)−1 to 11.057 kWh (kg COD removal)−1 using Na2SO4 as a supporting electrolyte. Gas chromatographic analysis of raw and treated wastewater also revealed that most normal hydrocarbons (nearly 99%) were removed during the electrocoagulation process.
Advanced Methods for the Elimination of Microorganisms in Industrial Treatments: Potential Applicability to Wastewater Reuse
Authors: Poyatos J. M. , Almecija M. C. , García‐Mesa J. J. , Muñio M. M. , Hontoria E. , Torres J. C. , Osorio F.
Published: March 2011

Because of the growing need to eliminate undesirable microorganisms in different industrial treatments, mainly in the food and agricultural sector and the pharmaceutical industry, a number of increasingly effective systems for disinfection to eliminate microorganisms have been devised. This article analyzes different methods to eliminate and/or significantly reduce the number of microorganisms in industrial contexts and in environmental engineering. Although, in the past, thermal treatments had been used most frequently for microbial elimination, the method is costly and has the disadvantage of modifying the organoleptic and/or physicochemical properties of the food products. For this reason, new technologies rapidly are being developed, such as high‐intensity pulsed electric fields, high‐pressure systems, ultrasounds, and irradiation, which effectively eliminate microorganisms without deteriorating the properties of the product. These emerging technologies are potentially applicable in the field of environmental engineering.
Learning from Past Treatments and Their Outcome Improves Prediction of In Vivo Response to Anti-HIV Therapy
Authors: Saigo Hiroto , Altmann Andre , Bogojeska Jasmina , Müller Fabian , Nowozin Sebastian , Lengauer Thomas
Published: March 2011

Infections with the human immunodeficiency virus type 1 (HIV-1) are treated with combinations of drugs. Unfortunately, HIV responds to the treatment by developing resistance mutations. Consequently, the genome of the viral target proteins is sequenced and inspected for resistance mutations as part of routine diagnostic procedures for ensuring an effective treatment. For predicting response to a combination therapy, currently available computer-based methods rely on the genotype of the virus and the composition of the regimen as input. However, no available tool takes full advantage of the knowledge about the order of and the response to previously prescribed regimens. The resulting high-dimensional feature space makes existing methods difficult to apply in a straightforward fashion. The machine learning system proposed in this work, sequence boosting, is tailored to exploiting such high-dimensional information, i.e. the extraction of longitudinal features, by utilizing the recent advancements in data mining and boosting.

When applied to predicting the latest treatment outcome for 3,759 treatment-experienced patients from the EuResist integrated database, sequence boosting achieved superior performance compared to SVMs with RBF kernels. Moreover, sequence boosting allows an easy access to the discriminative treatment information.

Analysis of feature importance values provided by our model confirmed known facts regarding HIV treatment. For instance, application of potent and recently licensed drugs was beneficial for patients, and, conversely, the patient group that was subject to NRTI mono-therapies in the past had poor treatment perspectives today. Furthermore, our model revealed novel biological insights. More precisely, the combination of previously used drugs with their in vivo response is more informative than the information of previously used drugs alone. Using this information improves the performance of systems for predicting therapy outcome.
In Vitro Antiplasmodial and Cytotoxic Activities of Ethanol Extracts of Apical Stem of Phyllanthus amarus Schum. et Thonn. (Euphorbiaceae)
Authors: Musuamba C.T. , Cimanga Richard K , Dooghe L. , Mesia G.K. , Luyindula N. , Totté J. , Pieters L. , Tona G.L. , Vlietinck A.J.
Published: March 2011

The in vitro antiplasmodial and cytotoxic activities of ethanol extracts from whole plant, fresh apical stems and calli from fresh apical stem of Phyllanthus amarus cultured on Murashige and Skoog (MS) medium supplemented with indole-butyric acid (IBA)/benzylaminopurine (BAP) 1:1, 1:2, 1:4 and 1:4, IBA/BAP/mannitol 1:1:0.5%, IBA/BAP/mannitol: 2% for three months were evaluated. Results indicated that all ethanol extracts showed an in vitro antiplasmodial activity at different extends. The most active ethanol extract was that from callus cultivated with IBA/BAP/mannitol 1:1:05% (IC50 < 0.19 µg/ml). The ethanol whole plant and intact apical stem extracts exhibited an activity with IC50 values of 2.5 ± 0.4 and 8.2 ± 1.9 µg/ml, respectively. Quercetin, lupeol and ellagic acid displayed an antiplasmodial activity with IC50 values of 3.2 ± 0.6, 8.3 ± 1.4 and 0.07 ± 0.02 µg/ml, respectively. All ethanol extracts and isolated compounds were considered to be non cytotoxic against MT-4 cell lines growth (CC50 > 32 µg/ml).
Chemical Characterization and Evaluation of the Hypoglycemic Effect of Fructooligosaccharides from Psacalium decompositum
Authors: Jimenez-Estrada Manuel , Merino-Aguilar Hector , Lopez-Fernandez Adriana , Rojano-Vilchis Nadia A. , Roman-Ramos Ruben , Alarcon-Aguilar Francisco Javier
Published: March 2011

Psacalium decompositum (Gray) H.E. Rob. & Brett (Asteraceae), popularly known as matarique, is a medicinal plant used in Mexico for the empirical treatment of diabetes mellitus. Previous studies with P. decompositum roots demonstrated that an aqueous fraction containing carbohydrates (WMP-fraction) exhibited a notable hypoglycemic effect in experimental animals. However, studies to identify these carbohydrates have not yet been performed. The goal of this investigation was to isolate and characterize the principal compounds in the WMP-fraction by spectroscopic and spectrometric analysis. Additionally, we sought to evaluate the hypoglycemic effect of these compounds in healthy and alloxan-induced diabetic mice. The results show that the chemical structures of the major compounds in the WMP-fraction correspond with fructan-type oligosaccharides and have a hypoglycemic effect in healthy and diabetic mice.
Antihypertensive and Vasorelaxant Effects of Cinnamomum zeylanicum Stem Bark Aqueous Extract in Rats
Authors: Nyadjeu Paulin , Dongmo Alain , Nguelefack Télesphore Benoît , Kamanyi Albert
Published: March 2011

The present study was undertaken to evaluate the antihypertensive and vasorelaxant effects of Cinnamomum zeylanicum Blume stem bark aqueous extract in rats. The in vivo activities of the extract were evaluated on normotensive and three rat models of hypertension while the in vitro tests were assayed on rat isolated aorta rings. Acute intravenous injection of the extract (5, 10 and 20mg/kg) induced a significant reduction in mean arterial blood pressure in anaesthetised normotensive Wistar rats, salt-loaded hypertensive, L-NAME hypertensive and spontaneously hypertensive rats. Pre-treatment of rats with either propranolol or atropine significantly inhibited the hypotensive effects of the plant extract suggesting its possible action through the interferences with both cholinergic and sympathetic transmissions. Moreover, pre-treatment of rats with L-NAME inhibited the sustained plant antihypertensive effects, suggesting a possible active vasodilatation, which might be partly mediated by an endothelial l-arginine/nitric oxide pathway. In isolated rat aortic rings pre-contracted with KCl (60mM), the extract exhibited cumulative vasodilating effects, which were attenuated with either L-NAME, vascular endothelium removal or both tetraethylammonium and glibenclamide pre-treatments. The vasorelaxant effects may be involved in the extract antihypertensive mechanism, partially by increasing the endothelial nitric oxide and by activating the KATP channels in vascular smooth muscle.
Structural Reforms and Budget Deficits in a Monetary Union: A Strategic Approach
Authors: Campoy Juan Cristóbal , Negrete Juan C.
Published: March 2011

This paper explores the interrelations between budget deficits and structural reforms in a monetary union. The analysis considers the international spillovers generated by both policies. We show that efforts to achieve fiscal policy coordination within the Eurozone reduce member countries' incentives to carry out much-needed structural reforms. As a consequence, this cooperation can turn out to be welfare-reducing if it is not extended to the implementation of structural reforms.
North American Integration and Canadian Foreign Direct Investment
Authors: Waldkirch Andreas , Tekin-Koru Ayça
Published: March 2011

We investigate how economic integration in North America has altered the pattern of foreign direct investment (FDI) to and from Canada. The theoretical analysis suggests that while the Canadian-U.S. free trade agreement should generate less FDI, the addition of Mexico in the North American Free Trade Agreement (NAFTA) produces the opposite effect. The fall in trade costs results in investment diversion from the U.S. and Canada, yet lower fixed costs may increase FDI even in those countries via an increased incentive to locate production facilities abroad rather than only domestically. Using a difference-in-differences estimator, we find that U.S. FDI in Canada as well as Canadian FDI in the U.S. have expanded disproportionately since NAFTA, suggesting that the latter effect dominates.
On two new families of iterative methods for solving nonlinear equations with optimal order
Authors: Heydari M. , Hosseini S.M. , Loghmani G.B.
Published: March 2011

In this paper, two new families of eighth-order iterative methods for solving
nonlinear equations is presented. These methods are developed by combining a
class of optimal two-point methods and a modified Newton?s method in the
third step. Per iteration the presented methods require three evaluations of
the function and one evaluation of its first derivative and therefore have
the efficiency index equal to 1:682. Kung and Traub conjectured that a
multipoint iteration without memory based on n evaluations could achieve
optimal convergence order 2n?1. Thus the new families of eighth-order methods
agrees with the conjecture of Kung-Traub for the case n = 4. Numerical
comparisons are made with several other existing methods to show the
performance of the presented methods.
Irrational evaluations and antisocial behavior of adolescents
Authors: Vukosavljevic-Gvozden Tatjana , Opacic Goran , Maric Zorica
Published: March 2011

The principles of the Rational Emotive Behavior Therapy point out to the role
of irrational beliefs in the occurrence of aggressive and antisocial
behavior. The goal of this research is to determine whether there are links
between irrational beliefs and self-assessment of antisocial behavior and
whether there are differences with respect to irrational beliefs between the
young who were sentenced by juvenile court judges compared to the control
group. The research was conducted on two subsamples - the first consisted of
male adolescents (N=116), aged 16 to 19, and the second comprised male
adolescents 50 out of whom were sentenced by juvenile court judges, aged
averagely 17 and a half, and 50 members of the control group. The modified
version of the General Attitude and Belief Scale (GABS) (Maric, 2002, 2003)
and Antisocial Behavior Scale (ABS) (Opacic, 2010, in print) were used.
Multiple regression analysis showed that the best predictor of the score on
antisocial behavior scale was ?the demand for absolute correctness of others
and their devaluation?, followed by the aspiration towards perfectionism and
success which acts as the factor that reduces the probability of antisocial
behavior. Almost identical results were obtained by group comparison. The
obtained results provide guidelines for designing preventive programs
(sketched in the discussion) that would be able to reduce the frequency of
aggressive and antisocial behavior at adolescent age.
Incorporating Active Learning Techniques in an Introduction to Psychology Course
Authors: Karafantis Dina M. , Lapadula Maria
Published: March 2011

The impact of active learning techniques on student learning outcomes was assessed across two studies. Performance data from two parallel sections of Introduction to Psychology (one traditional and one redesigned in which active learning techniques as well as online activities were incorporated into each lecture) were compared. Data from the traditional and redesigned sections on three identical semester tests, final exam grades and overall course grades were compared. Study 1 results indicate that students in the redesigned section performed as well as students in the traditional section on the semester tests and the final exam. The final grade distribution did not differ significantly between the traditional and redesigned sections. However, in Study 2, when controlling for instructor and teaching style, the results indicate that the redesigned section performed significantly better on all measures compared to the traditional section.
Got Neurons? Teaching Neuroscience Mnemonically Promotes Retention and Higher-Order Thinking
Authors: Richmond Aaron S. , Carney Russell N. , Levin Joel R.
Published: March 2011

The purpose of this study was to determine whether introductory psychology students could make effective use of the mnemonic keyword method in: (a) initially acquiring 26 neuroscience terms; (b) retaining this information over time; and (c) applying what they learned to a task requiring some degree of higher-order thinking. In two separate classes, 70 participants were trained either to use the keyword method or their own best method to study the neuroscience terms. After a 5-day delay, students returned to complete an unannounced assessment of the neuroscience terms. Based on a reduced sample of 58 ‘eligible’ participants, results indicated that students using the keyword method outperformed their own-best-method counterparts on immediate, delayed, and higher-order thinking assessments. The findings support the literature on the utility and power of the keyword method in actual psychology classroom learning contexts.
The Class Interview: Student Engagement in Courses Covering Sensitive Topics
Authors: Case Kim A.
Published: March 2011

Given the range of sensitive topics covered in many psychology courses, building community among students may encourage participation and impact student learning. This study investigated student responses to an interview activity used within several diversity courses in psychology. During the class interview, the instructor gathered information about students' backgrounds, concerns, and fears associated with the course, and their needs for successful learning. The second phase of the interview gave students the opportunity to interview the instructor. In a post-activity survey, students ( N = 131) reported their approval of the exercise with recommendations that faculty use it in more courses. Participants also indicated that the interview process encouraged student participation in class discussions, created a more comfortable classroom environment, and clarified course expectations. Several students specifically credited the interview exercise with promoting ‘collaboration with peers’ and creating a ‘sense of community’. They also indicated they appreciated the chance to ‘get to know other students’ as well as the ‘professor's concern for student opinions’.
A Case Study on Cost Estimation and Profitability Analysis at Continental Airlines
Authors: Roma´n Francisco J.
Published: March 2011

ABSTRACT: This case exposes students to the application of regression analyses to be used as a tool pursuant to understanding cost behavior and forecasting future costs using publicly available data from Continental Airlines. Specifically, the case focuses on the harsh financial situation faced by Continental as a result of the recent financial crisis and the challenges it faces to remain profitable. It then highlights the importance of reducing and controlling costs as a viable strategy to restore profitability and how regression analysis can assist in this pursuit. Students are next presented with quarterly data for various categories of costs and several potential cost drivers, which they must use to perform regressions on operating costs using a variety of cost drivers. They must then use their regression results to forecast operating costs and conduct a profitability analysis to project quarterly profits for the upcoming fiscal year. Finally, students must summarize the main results of their analysis in a memorandum addressed to Continental’s management, providing recommendations to restore profits. In particular, the concept of mixed cost functions is reinforced, as is the understanding of the steps required to perform regression analysis in Excel, interpreting the regression output, and the underlying standard assumptions in regression analysis. The case has been tested and well received in an intermediate cost accounting course and it is suitable for both undergraduate and graduate students.
Binge Eating, Mood, and Quality of Life in Youth With Type 2 Diabetes
Authors:   The TODAY Study Group
Published: March 2011

OBJECTIVE

The current study examines the prevalence of binge eating and its association with adiposity and psychosocial functioning in a large, diverse sample of youth with type 2 diabetes.

RESEARCH DESIGN AND METHODS

In the TODAY study, 678 (mean age 14.0 years; 64.9% girls) of the 704 youth randomized to the study completed a self-report measure of eating disorder symptoms and were categorized as nonovereaters, overeaters, subclinical binge eaters, or clinical binge eaters.

RESULTS

Youth with clinical (6%) and subclinical (20%) levels of binge eating had significantly higher levels and rates of extreme obesity, global eating disorder and depressive symptoms, and impaired quality of life.

CONCLUSIONS

These findings highlight the importance of evaluating youth with type 2 diabetes for the presence of binge eating. Future research is needed to determine the cumulative effects of disordered eating, obesity, and psychosocial distress on adherence to lifestyle change recommendations and longitudinal response to treatment.
Effects of Aging on the Morphology of Rubber-Brass Interfacial Layer
Authors: Ashirgade A. , Harakuni P. B. , Vanooij W. J.
Published: March 2011

Adhesion between rubber compound and brass-plated steel tire cord is crucial in governing the overall performance of tires. The rubber-brass interfacial adhesion is influenced by the chemical composition and thickness of the interfacial layer. It has been shown that the interfacial layer consists mainly of sulfides and oxides of copper and zinc. This paper discusses the effect of changes in the chemical composition and the structure of the interfacial layers due to addition of adhesion promoter resins. Grazing incidence x-ray diffraction (GIXRD) experiments were run on sulfidized polished brass coupons previously bonded to five experimental rubber compounds. It was confirmed that heat and humidity conditions lead to physical and chemical changes of the rubber-steel tire cord interfacial layer, closely related to the degree of rubber-brass adhesion. Morphological transformation of the interfacial layer led to loss of adhesion after aging. The adhesion promoter resins inhibit unfavorable morphological changes in the interfacial layer, thus stabilizing it during aging and prolonging failure. Tire cord adhesion tests illustrated that the one-component resins improved adhesion after aging using a rubber compound with lower cobalt loading. Based on the acquired diffraction profiles, these resins were also found to impede crystallization of the sulfide layer after aging, leading to improved adhesion. Secondary ion mass spectrometry depth profiles and scanning electron microscopy micrographs strongly corroborated the findings from GIXRD. This interfacial analysis adds valuable information to our understanding of the complex nature of the rubber-brass bonding mechanism.
Evaluation of the ability of aqueous black walnut extracts to induce the production of reactive oxygen species
Authors: Hurley David J. , Hurley Katherine A. E. , Galland Kimberly L. , Baker Bradley , Berghaus Londa J. , Moore James N. , Majerle Rita S. K.
Published: March 2011

Objective—To assess the in vitro capability of aqueous black walnut extracts (BWEs) to generate reactive oxygen species in water-based media ranging in makeup from a simple buffer solution to a complex solution containing serum.

Sample—3 BWEs.

Procedures—Production of reactive oxygen species by BWEs prepared in water or N-hexane was tested in PBS solution, PBS solution containing 0.5% bovine serum albumin and 5mM glucose (PBG), and RPMI-1640 medium (RPMI) containing 10% fetal bovine serum or 10% donor horse serum. Reactive oxygen species production was measured as conversion of nonfluorescent dihydrorhodamine 123 by reactive oxygen species to its fluorescent product, rhodamine-123. Hydrogen peroxide was used as a standard for reactive oxygen species activity.

Results—BWEs prepared in water generated reactive oxygen species in a dose-dependent manner over a 4-hour period, with peak activity detected when the BWEs were added as 10% (vol/vol) of the RPMI. The BWE prepared in N-hexane generated maximal reactive oxygen species activity after incubation for 3 to 4 hours when added at concentrations ranging from 0.3% to 0.5% (vol/vol) of the RPMI. The BWE prepared in water generated the highest fluorescent signal in PBS solution, whereas the BWE prepared in N-hexane generated the highest fluorescent signal in PBG.

Conclusions and Clinical Relevance—The BWEs prepared in water generated a dose-dependent induction of fluorescence in all the water-based solutions tested. These findings indicated that the BWEs, which are used to induce laminitis in horses, generate reactive oxygen species.
Symmetry of hind limb mechanics in orthopedically normal trotting Labrador Retrievers
Authors: Colborne G. Robert , Good Louise , Cozens Lucy E. , Kirk Lisa S.
Published: March 2011

Objective—To evaluate symmetry of the hind limbs in orthopedically normal trotting dogs.

Animals—19 orthopedically normal Labrador Retrievers with no history of lameness.

Procedures—Retroreflective markers were applied to the hind limb joints, and a 4-camera kinematic system captured positional data at 200 Hz in tandem with force platform data collection while the dogs trotted. Morphometric data were combined with kinematic and force data in an inverse dynamics method to calculate net joint moments and powers at the joints as well as total support moment for each limb. Dogs were identified as right or left dominant when their total support moment was > 10% asymmetric between sides.

Results—10 of the 19 dogs were mechanically dominant in the right hind limb as determined by their total support moments. One dog was left dominant, and the remaining 8 were symmetric. Right-dominant dogs had larger net joint moments at the right hip, tarsal, and metatarsophalangeal joints and a smaller moment at the right stifle joint, compared with values for the left hind limb. The 1 left-dominant dog had the exact opposite findings. Hip and stifle joint moments and powers varied between limbs of the right-dominant and left-dominant groups in the timing of their transition from negative to positive, and power amplitudes varied at the hip, tarsal, and metatarsophalangeal joints but not the stifle joint.

Conclusions and Clinical Relevance—Sound trotting dogs can have asymmetries in limb and joint mechanics. These natural mechanical asymmetries should be taken into account when considering models to evaluate stresses at joints and when considering surgery for cruciate ligament rupture.