bluuebunny/crossref_metadata_2025 huggingface dataset:
Malaysia's Response to the China Challenge
Authors: Yusof Zainal Aznam
Published: February 2004

Malaysia is a rapidly growing and resource-rich country that has been industrializing since the late 1960s. Its industrialization has relied on the growth of labor-intensive industries, particularly the electronics and electrical-products industries, which have contributed significantly to the growth of the manufacturing sector. The growth and opening up of China has raised concerns about Malaysia's loss of competitiveness to China and the diversion of foreign direct investment to China. This paper examines the relative competitive position of Malaysia and China and explores Malaysia's responses and policy options, both international and national, to the challenges posed by China. The following policy recommendations for Malaysia are explored: working intensively with its partners in ASEAN to develop a common stand with regard to trade arrangements, forming bilateral free trade agreements with selected countries, restructuring Malaysia's manufacturing industries so they are far less dependent on labor-intensive industries, and improving the education and technological skills of Malaysia's labor force.
Will Taiwan Be Marginalized by China?
Authors: Chen Tain-Jy
Published: February 2004

This paper shows that Taiwan has benefited immensely from China's accession to the World Trade Organization, in terms of the expansion of its exports to China, owing to Taiwan's institutional and structural advantages. Behind the rapid expansion of trade and investment, however, Taiwan runs a high risk of hollowing out its domestic industries, a risk that is manifested in a decline in exports, a loss of control over logistics functions that serve the export industry, and the relocation of research and development activities to China. Taiwan is facing an uphill battle of keeping its capital- and knowledge-intensive industries at home while attempting to take advantage of low-cost Chinese labor to retain its position in the world market.
Regionalism and Free Trade Agreements in East Asia
Authors: Cheong Inkyo
Published: February 2004

This paper gives an overview of the progress of regionalism in East Asia and examines the background of the recent embrace of trade agreements by China, Japan, and South Korea. It discusses the progress toward free trade agreements (FTAs) within East Asia and offers reasons for their slow development. The impacts of eight hypothetical East Asian FTAs are estimated using a computable generalized equilibrium model. The model predicts that countries will benefit from both bilateral FTAs and regional FTAs (such as a Northeast Asian FTA and an East Asian FTA); however, greater economic benefits would be gained under regional FTAs than under bilateral FTAs. Although the simulation used in the study estimates that a Northeast Asian FTA and an East Asian FTA would bring a similar level of economic benefits, results indicate that greater benefits would accrue under an East Asian FTA.

Discussions of a Japan–ASEAN FTA are under way, after talks of an FTA between ASEAN and China blossomed in late 2000. China and Japan are competitively promoting bilateral FTAs with ASEAN. As discussions of an FTA with ASEAN heat up in China and Japan, South Korea has also begun reviewing the economic feasibility of an FTA with ASEAN. If China, Japan, and South Korea competitively pursue bilateral FTAs with ASEAN, this may result in several important problems, including spaghetti bowl effects, a hub-and-spoke dilemma, or struggles for regional leadership.

This paper tries to show that an East Asian FTA covering the whole region is economically desirable and stresses that East Asian countries should introduce a regionwide FTA, rather than multiple bilateral or subregional FTAs. An East Asian FTA can be realized only in the long term because of economic, political, and social obstacles. East Asia, which already lags behind other regions in terms of regionalism, should not passively wait for the establishment of an East Asian FTA, which is likely to take some time to be established.
Efectos positivos de la activación del conflicto de tarea sobre el clima de los equipos de trabajo
Authors: Medina Francisco-J. , Munduate Lourdes , Martínez Inés , Dorado Miguel-A. , Mañas Miguel-A.
Published: January 2004

El objetivo del presente trabajo es analizar las relaciones existentes entre el tipo de conflicto—centrado en las tareas vs. centrado en las relaciones—y el clima en los equipos de trabajo. 169 empleados de diferentes organizaciones de servicios fueron analizados. El tipo de conflicto se midió mediante la escala de Jehn (1995)—conflicto de tarea—y la escala de Cox (1998, cfr., Friedman, Tidd, Currall y Tsai, 2000)—conflicto relacional—; el clima organizacional fue medido mediante la escala FOCUS- 93 (van Muijen et al., 1999). Los resultados confirman que un determinado nivel de controversia entre los empleados en cuanto a aspectos relacionados con la actividad laboral, facilita la aparición de un clima laboral caracterizadopor la creatividad y la adopción de retos laborales; mientras que un elevado conflicto centrado en las relaciones personales afecta negativamente al clima de dichos equipos de trabajo. Del mismo modo se confirma que la satisfacción de los trabajadores se incrementa cuando éstos pueden plantear controversias constructivas sobre del trabajo, en un clima laboral que permita la consecución de objetivos grupales.
Socialización policial: un estudio con una promoción de nuevo ingreso
Authors: Bravo Margarita , Gómez-Jacinto Luis , Montalbán F.-Manuel
Published: January 2004

El presente trabajo aborda la socialización en ambientes laborales como un proceso continuo de ajuste cuyo éxito repercute en el bienestar personal y en actitudes positivas hacia el trabajo. Se ha llevado a cabo una investigación, con tres momentos de medida, sobre una población que se incorpora a la Policía Local del Ayuntamiento de Málaga. La muestra inicial de jóvenes reclutas es de 158, completando todas las evaluaciones 68 sujetos. Se propone un modelo de socialización en el que se establece la influencia de variables relativas a la persona, al puesto y a los contenidos de socialización sobre los resultados de ajuste indiviuo-organización. La secuencialidad de estas relaciones se estudian a través del empleo de ecuaciones estructurales. El modelo estructural propuesto se ajusta a los datos empíricos y los resultados obtenidos son confirmatorios en la mayoría de las relaciones hipotéticas planteadas. Estos resultados apoyan el valor predicitivo que las expectativas iniciales sobre el puesto tienen sobre la socialización y el alto efecto positivo ejercido de los contenidos de la socialización laboral sobre el ajuste laboral.
Consumo de alcohol y estilos de vida: una tipología de los adolescentes españoles
Authors: Carrasco Ana-María
Published: January 2004

Este trabajo se centra en analizar el consumo de alcohol en los adolescentes en el contexto de sus estilos de vida. En concreto, pretende establecer una tipología de los estilos de vida y conocer si el consumo de alcohol es una característica definitoria del modus vivendi de determinados grupos de adolescentes. La muestra es representativa de los adolescentes escolarizados españoles de once, trece, quince y diecisiete años (n=5.985). El sistema de muestreo ha sido aleatorio, estratificado, proporcional, polietápico y por conglomerados. Se utilizó un cuestionario anónimo que los escolares cumplimentaron en sus aulas. Se han utilizado técnicas de análisis multivariantes, combinando análisis de correspondencias múltiples y técnicas de clasificación automática. La tipología obtenida distingue seis clases. Las clases que reflejan hábitos saludables, satisfacción escolar y percepción de apoyo familiar abarcan a los adolescentes de menor edad. Entre los adolescentes de mayor edad consumidores de alcohol y tabaco se observan dos perfiles, diferenciados por el género. Las chicas, a diferencia de los chicos, se caracterizan por una vida sedentaria, trastornos en los hábitos de alimentación y frecuentes trastornos psicosomáticos. Se ofrecen sugerencias para la elaboración de programas de promoción de salud.
Biomechanical Properties of Patellar and Hamstring Graft Tibial Fixation Techniques in Anterior Cruciate Ligament Reconstruction
Authors: Adam Frank , Pape Dietrich , Schiel Karin , Steimer Oliver , Kohn Dieter , Rupp Stefan
Published: February 2004

Background

Reliable fixation of the soft hamstring grafts in ACL reconstruction has been reported as problematic.

Hypothesis

The biomechanical properties of patellar tendon (PT) grafts fixed with biodegradable screws (PTBS) are superior compared to quadrupled hamstring grafts fixed with BioScrew (HBS) or Suture-Disc fixation (HSD).

Study Design

Controlled laboratory study with roentgen stereometric analysis (RSA).

Methods

Ten porcine specimens were prepared for each group. In the PT group, the bone plugs were fixed with a 7 · 25 mm BioScrew. In the hamstring group, four-stranded tendon grafts were anchored within a tibial tunnel of 8 mm diameter either with a 7 · 25 mm BioScrew or eight polyester sutures knotted over a Suture-Disc. The grafts were loaded stepwise, and micromotion of the graft inside the tibial tunnel was measured with RSA.

Results

Hamstring grafts failed at lower loads (HBS: 536 N, HSD 445 N) than the PTBS grafts (658 N). Stiffness in the PTBS group was much greater compared to the hamstring groups (3500 N/mm versus HBS = 517 N/mm and HSD = 111 N/mm). Irreversible graft motion after graft loading with 200 N was measured at 0.03 mm (PTBS), 0.38mm (HBS), and 1.85mm (HSD). Elasticity for the HSD fixation was measured at 0.67 mm at 100 N and 1.32 mm at 200 N load.

Conclusion

Hamstring graft fixation with BioScrew and Suture-Disc displayed less stiffness and early graft motion compared to PTBS fixation. Screw fixation of tendon grafts is superior to Suture-Disc fixation with linkage material since it offers greater stiffness and less graft motion inside the tibial tunnel.

Clinical Relevance

Our results revealed graft motion for hamstring fixation with screw or linkage material at loads that occur during rehabilitation. This, in turn, may lead to graft laxity.
A Clinical and Roentgenographic Study of Little League Elbow
Authors: Hang David Wei , Chao Chien Ming , Hang Yi-Shiong
Published: February 2004

Background

Comparisons of medial elbow injury rate and the incidence of clinical and radiographic findings among Little League baseball players have not been documented.

Hypothesis

Injury rate and clinical and radiographic findings in Little Leaguers of different positions may be similar.

Study Design

Survey and retrospective review.

Methods

Altogether, 343 Little Leaguers (120 pitchers, 40 catchers, and 183 fielders) participated in the study. The survey (including age, playing position, playing experience, and symptoms), clinical examination, and roentgenogram of both elbows were obtained for analysis using Pearson's chi-square test.

Results

Clinically, 58% of the pitchers presented with soreness compared to 63% in catchers and 47% in fielders. Radiographic examination revealed hypertrophy of the medial humeral epicondyle in all pitchers and catchers and 90% of the fielders. Separation of the medial epicondyle was found in 63% of pitchers, 70% of catchers, and 50% of fielders, while fragmentation was found in 19% of pitchers, 40% of catchers, and 15% of fielders. In subjects with separation or fragmentation, 49% and 56% complained of elbow soreness, respectively.

Conclusion

Similar rates of medial elbow changes in Little Leaguers may imply that the roentgenological changes of the medial epicondyle could be an adaptive yet physiological reaction to the excessive valgus stress of throwing. The higher incidence of medial epicondylar separation and fragmentation in catchers that has not been reported before may be secondary to the increased stress placed on the elbow when throwing from the squatting position.
Prospective Evaluation of Thermal Capsulorrhaphy for Shoulder Instability
Authors: D'Alessandro Donald F. , Bradley James P. , Fleischli James E. , Connor Patrick M.
Published: February 2004

Background

Thermal shrinkage of capsular tissue has recently been proposed as a means to address the capsular redundancyassociated with shoulder instability. Although this procedure has become very popular, minimal peer-reviewed literature isavailable to justify its widespread use.

Purpose

To prospectively evaluate the efficacy of arthroscopic electrothermal capsulorrhaphy for the treatment of shoulderinstability.

Study Design

This nonrandomized prospective study evaluated the indications and results of thermal capsulorrhaphy in 84shoulders with an average follow-up of 38 months.

Methods

Patients were divided into three clinical subgroups: traumatic anterior dislocation (acute or recurrent), recurrent anterioranterior/inferior subluxation without prior dislocation, and multidirectional instability. Patients underwent arthroscopic thermalcapsulorrhaphy after initial assessment, radiographs, and failure of a minimum of 3 months of nonoperative rehabilitation.

Results

Outcome measures included pain, recurrent instability, return to work/sports, and the American Shoulder and ElbowSurgeons (ASES) Shoulder Assessment score. Overall results were excellent in 33 participants (39%), satisfactory in 20 (24%),and unsatisfactory in 31 (37%).

Conclusions

The high rate of unsatisfactory overall results (37%), documented with longer follow-up, is of great concern. Theauthors conclude that enthusiasm for thermal capsulorrhaphy should be tempered until further studies document its efficacy.
Football Injuries at Asian Tournaments
Authors: Yoon Young Sul , Chai Michelle , Shin Dong Won
Published: February 2004

Purpose

To examine the incidences and patterns of injuries that required medical attention among Asian football players.

Methods

A total of 411 Asian football players at both senior and youth (U-20) elite levels were observed during 50 international matches. Independent injury observers and team doctors determined the occurrence of injuries and recorded the location, type, time, and circumstances of the injuries using a protocol sheet.

Results

The overall injury frequency rate was 45.8 out of 1000 hours. As the tournaments progressed into the knockout stages, the incidence and severity of the injuries increased. The most common sites of injuries were the knees (18.5%), lower legs (17.3%), and ankles (14.2%). Although most injuries were diagnosed as contusions, the more serious injuries were those diagnosed as sprains (especially concerning the knee and ankle) or strains (thigh and back).

Conclusions

The incidences of injuries to Asian football players were higher than those to European players, but the patterns of the injuries showed no major differences.

Clinical Relevance

To develop an injury-prevention program, more solid and comprehensive data need to be collected to identify the risk factors and variables associated with higher incidences of injuries to Asian football players.
Cell-Based Therapy for Meniscal Repair
Authors: Peretti Giuseppe M. , Gill Thomas J. , Xu Jian-Wei , Randolph Mark A. , Morse Kenneth R. , Zaleske David J.
Published: February 2004

Background

The avascular portion of the meniscus cartilage in the knee does not have the ability to repair spontaneously.

Hypothesis

Cell-based therapy is able to repair a lesion in the swine meniscus.

Study Design

Controlled laboratory study.

Methods

Sixteen Yorkshire pigs were divided into four groups. A longitudinal tear was produced in the avascular portion of the left medial meniscus of 4 pigs. Autologous chondrocytes were seeded onto devitalized allogenic meniscal slices and were secured inside the lesion with two sutures. Identical incisions were created in 12 other pigs, which were used as three separate control groups: 4 animals treated with an unseeded scaffold, 4 were simply sutured, and 4 were left untreated. Meniscal samples were collected after 9 weeks, and the samples were analyzed grossly, histologically, and histomorphometrically.

Results

Gross results showed bonding of the lesion margins in the specimens of the experimental group, whereas no repair was noted in any of the control group specimens. Histological and histomorphometrical analysis showed multiple areas of healing in the specimens of the experimental group.

Conclusions

This study demonstrated the ability of seeded chondrocytes to heal a meniscal tear.

Clinical Relevance

Cell-based therapy could be a potential tool for avascular meniscus repair.
The Effect of Posterior Cruciate Ligament Reconstruction on Patellofemoral Contact Pressures in the Knee Joint under Simulated Muscle Loads
Authors: Gill Thomas J. , DeFrate Louis E. , Wang Conrad , Carey Christopher T. , Zayontz Shay , Zarins Bertram , Li Guoan
Published: February 2004

Background

The mechanism of cartilage degeneration in the patellofemoral joint (PFJ) and medial compartment of the knee following posterior cruciate ligament (PCL) injury remains unclear. PCL reconstruction has been recommended to restore kinematics and prevent long-term degeneration. The effect of current reconstruction techniques on PFJ contact pressures is unknown.

Purpose

To measure PFJ contact pressures after PCL deficiency and reconstruction.

Method

Eight cadaveric knees were tested with the PCL intact, deficient, and reconstructed. Contact pressures were measured at 30 °, 60 °, 90 °, and 120 ° of flexion under simulated muscle loads. Knee kinematics were measured by a robotic testing system, and the PFJ contact pressures were measured using a thin film transducer. A single bundle achilles tendon allograft was used in the reconstruction.

Results

PCL deficiency significantly increased the peak contact pressures measured in the PFJ relative to the intact knee under both an isolated quadriceps load of 400 N and a combined quadriceps/hamstrings load of 400 N/200 N. Reconstruction did not significantly reduce the increased contact pressures observed in the PCL-deficient knee.

Conclusion

The elevated contact pressures observed in the PCL-deficient knee and reconstructed knee might contribute to the long-term degeneration observed in both the non-operatively treated and PCL-reconstructed knees.
Delayed Anterior Cruciate Ligament Reconstruction in Adolescents with Open Physes
Authors: Woods G. William , O'Connor Daniel P.
Published: February 2004

Background

Treatment of anterior cruciate ligament rupture in adolescents with open physes is controversial.

Hypothesis

Delaying reconstruction until the physes bridge will affect the rate of additional knee injuries.

Study Design

Case control.

Methods

The physes group was 13 adolescents with open physes whose anterior cruciate ligament reconstructions were delayed until their physes bridged. Specific types of activity were absolutely restricted during the delay. The physes groups’ rates of additional injuries, identified arthroscopically at reconstruction, were compared to rates among 116 skeletally mature adolescents. The comparison adolescents were stratified into four groups by interval from injury to reconstruction (< 1 week, 1 to 6 weeks, 6 to 26 weeks, >26 weeks).

Results

The additional injury rates in the physes and four comparison groups were 46%, 50%, 47%, 43%, and 69%, respectively. Severity of additional injury, mechanism of injury, and rate of additional surgical procedures were similar among the groups.

Conclusions

There was no evidence that intentionally delayed anterior cruciate ligament reconstruction increased the rate of additional knee injuries. Delayed reconstruction is a valid treatment option for adolescents with open physes at injury. Absolute activity restriction is key to decreasing the risk of additional knee injuries.
Hip Adductor Injury in Competitive Swimmers
Authors: Grote Kurt , Lincoln Todd L. , Gamble James G.
Published: February 2004

Methods

The authors conducted a survey of 296 competitive swimmers to assess the incidence and importance of interfering groin pain in breaststroke swimmers.

Results

Breaststroke swimmers were more likely to have current groin pain (6.92%) than individual medley swimmers who did not compete in pure breaststroke events (0, P= 0.015). Breaststroke swimmers (42.7%) were also more likely than individual medley swimmers (21.5%, P= 0.000622) or nonbreaststroke, nonindividual medley swimmers (5.8%, P= 0.00000311) to have been unable to train breaststroke in practice during the past year due to groin injury.

Conclusion

Results indicate that breaststroke swimmers are at significant risk of groin injury, groin injury is positively correlated with increased magnitude of breaststroke training, and groin injury may prevent participation in practices and competitions.
Opening Wedge High Tibial Osteotomy for Symptomatic Hyperextension-Varus Thrust
Authors: Naudie Douglas D.R. , Amendola Annunziato , Fowler Peter J.
Published: February 2004

Background

The purpose of this study was to assess the functional outcome of opening wedge high tibial osteotomy (HTO) in a young, active group of patients with instability rather than osteoarthritis.

Methods

The results of 17 opening wedge HTOs in 16 patients with a symptomatic hyperextension-varus thrust were evaluated. Functional results were evaluated according to the activity scoring system of Tegner and Lysholm and using a 5-point visual analogue scale to assess change in knee stability and satisfaction. Radiographs were analyzed to determine changes in femorotibial and mechanical axis alignment, tibial slope, and patellar height.

Results

Patients were followed for a mean of 56 months. All patients had an increase in their activity score postoperatively. Nine patients rated their symptoms as significantly better and seven as somewhat better. All but one were satisfied with the surgery. Femorotibial axis alignment was changed to a mean of 6 ° valgus, mechanical axis alignment was corrected to a mean of 46% toward the lateral compartment, posterior tibial slope was increased a mean of 8 °, and the ratio of patellar height was decreased a mean of 0.17.

Conclusion

Opening wedge HTO can produce good functional and radiographic results in selected patients with a symptomatic thrust.
Characteristic Plantar Pressure Distribution Patterns during Soccer-Specific Movements
Authors: Eils Eric , Streyl Markus , Linnenbecker Stefan , Thorwesten Lothar , Völker Klaus , Rosenbaum Dieter
Published: February 2004

Purpose

To characterize in-shoe pressure measurements during different soccer-specific maneuvers on two playing surfaces to identify the main loading areas of the foot.

Methods

Twenty-one experienced male soccer players participated in the study (25.5 ± 1.8 years, 78.7 ± 5.4 kg, and 182.9 ± 5.7 cm). The Pedar Mobile system was used to collect plantar pressure information inside the soccer shoe. Four soccer-specific movements were performed (normal run, cutting maneuver, sprint, and goal shot) on both a grass and a red cinder surface.

Results

Results showed characteristic pressure distribution patterns with specific loading areas of the foot that correspond to the evaluated movements. In addition, loading patterns with higher pressure values than those observed during normal run were found. In cutting, the medial part of the foot; in sprinting, the first and second ray; and in kicking, the lateral part of the foot are predominantly loaded. No global effect of the two surfaces on pressure parameters was found.

Conclusion

The results of the present investigation suggest that the high load in soccer in combination with a high repetition may have an important influence in the development of overuse injuries.
Does the Patellar Tendon Normalize after Harvesting Its Central Third?
Authors: Svensson Michael , Kartus Jüri , Ejerhed Lars , Lindahl Sven , Karlsson Jon
Published: February 2004

Background

The central third of the patellar tendon is the most frequently used autograft for ACL reconstruction.

Hypothesis

The patellar tendon at the donor site would look normal as seen on MRI 6 years after harvesting its central third.

Methods

Nineteen consecutive patients were included in the study. MRI examinations of the donor site were performed at 6 (5 to 10) weeks, 6 (6 to 8) months, 27 (24 to 29) months, and 71 (68 to 73) months postoperatively. The contralateral normal side was examined only on the first occasion.

Results

The size of the donor-site gap decreased significantly (P = 0.0001) between 6 weeks and 6 years. In most patients, a thinning of the central part of the patellar tendon was still found at 6 years. The thickness of the peripheral patellar tendon was increased, compared with the contralateral healthy side, until 2 years (P = 0.003). On all occasions, the width was increased compared with the contralateral side (P< 0.015).

Conclusion

Prospective MRI examinations revealed that the patellar tendon at the donor site had not normalized 6 years after harvesting its central third. The reharvesting of the patellar tendon can therefore not be recommended.
Football Injuries during the World Cup 2002
Authors: Junge Astrid , Dvorak Jiri , Graf-Baumann Toni
Published: February 2004

Background

The Fédération Internationale de Football Association (FIFA) World Cup is one of the largest, most popular sporting events but is associated with a certain risk of injury for the players.

Purpose

Analysis of the incidence, circumstances, and characteristics of soccer injury during the World Cup 2002.

Study Design

Prospective survey.

Methods

The physicians of all participating teams reported all injuries after each match on a standardized injury report form. The response rate was 100%.

Results

A total of 171 injuries were reported from the 64 matches, which is equivalent to an incidence of 2.7 injuries per match; approximately 1 to 2 injuries per match resulted in absence from training or match. More than a quarter of all injuries were incurred without contact with another player, and 73% were contact injuries. Half of the contact injuries, or 37% of all injuries, were caused by foul play as rated by the team physician and the injured player.

Conclusion

The incidence of injuries during the World Cup 2002 was similar to those reported for the World Cup in 1994 and in 1998. Increased awareness of the importance of fair play may assist in the prevention of injury.
Rule Violations as a Cause of Injuries in Male Norwegian Professional Football
Authors: Andersen Thor Einar , Engebretsen Lars , Bahr Roald
Published: February 2004

Background

Foul play is an important cause of injury in football. Reduction of foul play and adherence to the laws of the game may be possible interventions to reduce the rate of injuries.

Purpose

To evaluate how violations of the laws of the game contribute to injury and to investigate whether the decisions made by the referees are correct in high-risk situations.

Study Design

Prospective cohort study.

Methods

Videotapes and injury information were collected for 174 of 182 matches from the male Norwegian professional league during the 2000 season. Three Norwegian FIFA referees performed retrospective blinded evaluation of the 406 incidents.

Results

Less than one-third of the injuries identified on video and about 40% of the incidents with a high risk of injury resulted in a free kick being awarded. About 1 in 10 of these situations led to either a yellow or red card. The agreement between decisions made by the match referee and the expert referee panel was good, that is, their decisions agreed in 85% of the situations in which injury occurred.

Conclusions

There may be a need for an improvement of the laws of the game of football to protect players from dangerous play.
Athletic Injuries of the Wrist and Hand
Authors: Rettig Arthur C.
Published: February 2004

Hand and wrist injuries in sports are some of the most common injuries reported. This review discusses common overuse injuries of the wrist including tendon injuries such as de Quervain's syndrome, subluxation of the extensor carpi ulnaris, and the common dorsal carpal impingement syndrome. The main focus of this section is the discussion of traumatic injuries to the hand in the athlete. Included is a discussion and review of fractures of the phalanges and metacarpals, common proximal interphalangeal joint injuries, and thumb carpal metacarpal and metacarpophalangeal joint injuries. Emphasis is placed on more common injuries seen regarding diagnosis, indications for non-operative versus operative treatment, and time to return to athletic competition.
Crosswell seismic imaging in a contaminated basalt aquifer
Authors: Daley Thomas M. , Majer Ernest L. , Peterson John E.
Published: January 2004

Multiple seismic crosswell surveys have been acquired and analyzed in a fractured basalt aquifer at Idaho National Engineering and Environmental Laboratory. Most of these surveys used a high‐frequency (1000–10,000 Hz) piezoelectric seismic source to obtain P‐wave velocity tomograms. The P‐wave velocities range from less than 3200 m/s to more than 5000 m/s. Additionally, a new type of borehole seismic source was deployed as part of the subsurface characterization program at this contaminated groundwater site. This source, known as an orbital vibrator, allows simultaneous acquisition of P‐ and S‐waves at frequencies of 100 to 400 Hz, and acquisition over larger distances. The velocity tomograms show a relationship to contaminant transport in the groundwater; zones of high contaminant concentration are coincident with zones of low velocity and high attenuation and are interpreted to be fracture zones at the boundaries between basalt flows. The orbital vibrator data show high Vp/Vs values, from 1.8 to 2.8. In spite of the lower resolution of orbital vibrator data, these data were sufficient for constraining hydrologic models at this site while achieving imaging over large interwell distances. The combination of piezoelectric data for closer well spacing and orbital vibrator data for larger well spacings has provided optimal imaging capability and has been instrumental in our understanding of the site aquifer's hydrologic properties and its scale of heterogeneity.
Revisiting the Wyllie time average equation in the case of near‐spherical pores
Authors: Saleh Azzeldeen A. , Castagna John P.
Published: January 2004

We suggest a generalized form of the Wyllie equation to better describe acoustic velocity variation with porosity in rocks with a mixture of intercrystalline and near‐spherical pores. Introducing a pore shape factor in the Wyllie equation allows different weights to be applied to the solid‐phase P‐wave velocity to account for rock frame stiffness. This is demonstrated in carbonate and igneous rocks having variable amounts of spherical porosity, ranging from 0% to 80% of the bulk porosity.

The generalized equation describes a velocity–porosity envelope instead of the simple line given by the Wyllie equation. The lower limit of the velocity envelope is for rocks that have only interparticle or intercrystalline porosity (Wyllie equation behavior), and the upper limit is when all pores are spherical or near spherical. This upper limit corresponds to the Hashin‐Shtrikman upper bound for porosities up to 30%. The realization portrays Wyllie's velocity–porosity relationship as one particular case in which all pores are intercrystalline or interparticle with a pore shape factor equal to unity. An increase in the amount of high‐aspect‐ratio pores leads to higher pore shape factor. We suspect that this factor may be generalized to include fracture porosity with values less than unity. We suggest that this factor represents the acoustic equivalent of the cementation factor in Archie's law for resistivity measurements.

The velocity calculated by the modified model correlates well with both the measured velocity and the calculated velocity using the Kuster‐Toksöz theoretical model. Various factors controlling acoustic velocity in carbonates can be quantified, based on this modification.
In‐situ apparent conductivity measurements and microbial population distribution at a hydrocarbon‐contaminated site
Authors: Atekwana Estella A. , Werkema D. Dale , Duris Joseph W. , Rossbach Silvia , Atekwana Eliot A. , Sauck William A. , Cassidy Daniel P. , Means Jay , Legall Franklyn D.
Published: January 2004

We investigated the bulk electrical conductivity and microbial population distribution in sediments at a site contaminated with light nonaqueous‐phase liquid (LNAPL). The bulk conductivity was measured using in‐situ vertical resistivity probes; the most probable number method was used to characterize the spatial distribution of aerobic heterotrophic and oil‐degrading microbial populations. The purpose of this study was to assess if high conductivity observed at aged LNAPL‐impacted sites may be related to microbial degradation of LNAPL. The results show higher bulk conductivity coincident with LNAPL‐impacted zones, in contrast to geoelectrical models that predict lower conductivity in such zones. The highest bulk conductivity was observed to be associated with zones impacted by residual and free LNAPL. Data from bacteria enumeration from sediments close to the resistivity probes show that oil‐degrading microbes make up a larger percentage (5–55%) of the heterotrophic microbial community at depths coincident with the higher conductivity compared to ∼5% at the uncontaminated location. The coincidence of a higher percentage of oil‐degrading microbial populations in zones of higher bulk conductivity suggests that the higher conductivity in these zones may result from increased fluid conductivity related to microbial degradation of LNAPL, consistent with geochemical studies that suggest that intrinsic biodegradation is occurring at the site. The findings from this study point to the fact that biogeochemical processes accompanying biodegradation of contaminants can potentially alter geoelectrical properties of the subsurface impacted media.
Numerical study of electromagnetic waves generated by a prototype dielectric logging tool
Authors: Ellefsen Karl J. , Abraham Jared D. , Wright David L. , Mazzella Aldo T.
Published: January 2004

To understand the electromagnetic waves generated by a prototype dielectric logging tool, a numerical study was conducted using both the finite‐difference, time‐domain method and a frequency‐wavenumber method. When the propagation velocity in the borehole was greater than that in the formation (e.g., an air‐filled borehole in the unsaturated zone), only a guided wave propagated along the borehole. As the frequency decreased, both the phase and the group velocities of the guided wave asymptotically approached the phase velocity of a plane wave in the formation. The guided wave radiated electromagnetic energy into the formation, causing its amplitude to decrease. When the propagation velocity in the borehole was less than that in the formation (e.g., a water‐filled borehole in the saturated zone), both a refracted wave and a guided wave propagated along the borehole. The velocity of the refracted wave equaled the phase velocity of a plane wave in the formation, and the refracted wave preceded the guided wave. As the frequency decreased, both the phase and the group velocities of the guided wave asymptotically approached the phase velocity of a plane wave in the formation. The guided wave did not radiate electromagnetic energy into the formation. To analyze traces recorded by the prototype tool during laboratory tests, they were compared to traces calculated with the finite‐difference method. The first parts of both the recorded and the calculated traces were similar, indicating that guided and refracted waves indeed propagated along the prototype tool.
Experimental design: Electrical resistivity data sets that provide optimum subsurface information
Authors: Stummer Peter , Maurer Hansruedi , Green Alan G.
Published: January 2004

Although multielectrode electrical‐resistivity systems have been commercially available for more than a decade, resistivity imaging of the subsurface continues to be based on data sets recorded using one or more of the standard electrode arrays (e.g., the Wenner or conventional dipole‐dipole array). To exploit better the full capabilities of multielectrode acquisition systems, we have developed an experimental design procedure to identify suites of electrode configurations that provide subsurface information according to predefined optimization criteria. The experimental design algorithm includes a goodness function that ranks the sensitivity of every possible electrode configuration to changes in the subsurface parameters. To examine the potential and limitations of the new algorithm, comprehensive data sets that included data from all standard and nonstandard electrode configurations were (a) generated for a complex 2D resistivity model and (b) recorded across a well‐studied test site in Switzerland. Images determined from the resultant comprehensive data sets were used as benchmarks against which the images derived from the optimized data sets were assessed. Images from relatively small optimized data sets, containing 265–282 data points, provided more information than did those from standard data sets of equal size. By far the best images, comparable to those determined from the much larger comprehensive data sets, were obtained from optimized data sets with 1000–6000 data points. These images supplied reliable information over depth ranges that were three times greater than the depth ranges resolved by the standard images. The first ∼600 electrode configurations selected by the experimental design procedure were nonstandard dipole‐dipole‐type arrays, whereas the following ∼4800 electrode configurations were an approximately equal mix of nonstandard dipole‐dipole‐type arrays and nested configurations (i.e., mostly gradient and other nonstandard arrays).
Numerical analysis of near‐borehole and anisotropeic layer effects on the response of multicomponent induction logging tools
Authors: Tompkins Michael J. , Alumbaugh David L. , Stanley Darrell T. , Lu Xinyou
Published: January 2004

We present finite‐difference simulation results that lend new insight into the behavior of multicomponent induction logging tools when in the presence of anisotropic layers, boreholes, and invasion zones. We use four independent models to investigate multicomponent tool properties as well as typical magnetic field responses. In addition, model variations with respect to formation dip angle, layer geometry, and conductivity provide data about the effects of geological variation on the multicomponent responses. Simulations suggest a coaxial tool configuration senses a depth of twice the source–receiver offset, although this depth is reduced to the source–receiver offset with coplanar configurations. Numerical responses in the presence of transversely isotropic layers provide evidence that anisotropy can have a measurable effect on both coaxial and coplanar magnetic fields; these effects increase as layer dip increases. Sensitivity analyses substantiate these numerical results. An investigation of tool responses to varying borehole and invasion zone conductivities and diameters demonstrates that the coplanar tool orientation is much more sensitive to near‐borehole variations than the coaxial configuration. A frequency‐differencing technique is presented to mitigate unwanted borehole‐induced bias in multicomponent data; however, drawbacks include decreased signal strength and possible geological signal destruction.
Use of the analytic signal to identify magnetic anomalies due to kimberlite pipes
Authors: Keating Pierre , Sailhac Pascal
Published: January 2004

The magnetic signature of most kimberlite pipes is, at high magnetic latitudes, a circular anomaly. At lower magnetic latitudes, it becomes asymmetric; and at the magnetic equator, the anomaly is mostly negative. The shape of the anomaly is also influenced by the presence of remanent magnetization. For a vertical cylinder, the shape of the analytic signal of the magnetic field is nearly independent of field orientation and remanence and always results in a compact, almost circular anomaly. A simple pattern recognition technique, based on a first‐order regression over a moving window, between the analytic signal of the observed magnetic field and the theoretical analytic signal of a magnetic vertical cylinder is an effective tool to identify potential targets. Results where the correlation coefficient between the analytic signal and the theoretical analytic signal within a moving window are above a certain threshold are retained, and additional criteria can later be used to refine the target selection. The method's practical utility is demonstrated by applying it to three different sites. The first is a well‐documented area located at high magnetic latitude (Ontario, Canada), the second is at low magnetic latitude (West Africa), and the last one is an area where many pipes have a negative magnetization (Lac de Gras, Canada).
Coupled geomechanics and flow simulation for time‐lapse seismic modeling
Authors: Minkoff Susan E. , Stone C. Mike , Bryant Steve , Peszynska Malgorzata
Published: January 2004

To accurately predict production in compactible reservoirs, we must use coupled models of fluid flow and mechanical deformation. Staggered‐in‐time loose coupling of flow and deformation via a high‐level numerical interface that repeatedly calls first flow and then mechanics allows us to leverage the decades of work put into individual flow and mechanics simulators while still capturing realistic coupled physics. These two processes are often naturally modeled using different time stepping schemes and different spatial grids—flow should only model the reservoir, whereas mechanics requires a grid that extends to the earth's surface for overburden loading and may extend further than the reservoir in the lateral directions. Although spatial and temporal variability between flow and mechanics can be difficult to accommodate with full coupling, it is easily handled via loose coupling. We calculate the total stress by adding pore pressures to the effective rock stress. In turn, changes in volume strain induce updates to porosity and permeability and, hence, dynamically alter the flow solution during simulation. Incorporating the resulting time‐dependent pressures, saturations, and porosities (from coupled flow and mechanics) into Gassmann's equations results in seismic wave velocities and densities that can differ markedly from those calculated from flow alone. In a synthetic numerical experiment based on Belridge field, California, incorporation of coupled flow and mechanical deformation into time‐lapse calculations produces compressional wave velocities that differ markedly from those produced by flow alone. In fact, it is the closing of the pores themselves (reduction in permeability) in this example which has the greatest impact on fluid pressures and saturations and, hence, elastic wave parameters such as velocity.
Separating P‐ and S‐waves in prestack 3D elastic seismograms using divergence and curl
Authors: Sun Robert , McMechan George A. , Hsiao Hsu‐Hong , Chow Jinder
Published: January 2004

The reflected P‐ and S‐waves in a prestack 3D, three‐component elastic seismic section can be separated by taking the divergence and curl during finite‐difference extrapolation. The elastic seismic data are downward extrapolated from the receiver locations into a homogeneous elastic computational model using the 3D elastic wave equation. During downward extrapolation, divergence (a scalar) and curl (a three‐component vector) of the wavefield are computed and recorded independently, at a fixed depth, as a one‐component seismogram and a three‐component seismogram, respectively. The P‐ and S‐velocities in the elastic computational model are then split into two independent models. The divergence seismogram (containing P‐waves only) is then upward extrapolated (using the scalar wave equation) through the P‐velocity model to the original receiver locations at the surface to obtain the separated P‐waves. The x‐component, y‐component, and z‐component seismograms of the curl (containing S‐waves only) are upward extrapolated independently (using the scalar wave equation) through the S‐velocity model to the original receiver locations at the surface to obtain the separated S‐waves. Tests are successful on synthetic seismograms computed for simple laterally heterogeneous 2D models with a 3D recording geometry even if the velocities used in the extrapolations are not accurate.
Multiple sclerosis: expression of C D1a and production of IL-12 p70 and IFN-γ by blood mononuclear cells in patients on combination therapy with IFN-β and glatiramer acetate compared to monotherapy with IFN-β
Authors: Hussien Yassir , Sanna Alessandra , Söderström Mats , Link Hans , Huang Yu-Min
Published: February 2004

Current therapy of multiple sclerosis (MS) with interferon-beta (IFN-b) or glatiramer acetate (GA) has modest effects on the course of MS. Both compounds affect several immune variables, like expression of cell surface molecules and cytokine levels. Here we compared untreated MS, therapy with IFN-b alone and combined with GA, and healthy controls (HC), regarding expression on HLA -DR+ blood mononuclear cells (MNC) of C D1a that is a cell surface molecule with capacity to present glycolipids to T cells, and of C D80 and C D86 which are costimulatory molecules that activate Th1 and Th2 responses. C ytokine production by MNC was also measured. Flow cytometry and ELISA were used. C ross-sectional comparisons revealed that untreated MS patients had higher C D1a+ HLA -DR+ MNC and lower IL-10 production compared to patients treated with IFN-b or IFN-b+G A or HC. Untreated MS patients also had higher spontaneous IFN-g and IL-12p70 production compared to MS patients treated with IFN-b+G A or HC, but not when compared to MS patients on monotherapy with IFN-b. Low C D1a+ HLA -DR+ MNC and low spontaneous production of IL-12p70 and IFN-g were more pronounced in patients treated with IFN-b+G A than with IFN-b alone. In order to clarify whether these changes reflect disease activity or treatment effects, we performed a follow up study. Nineteen MS patients with disease progression, despite monotherapy with IFN-b for more than one year, were re-examined after one to three and four to six months of treatment with IFN-b+G A. This combination therapy was associated with normalization of C D1a+ HLA -DR+ MNC, IL-12p70 and IFN-g. It remains to be shown whether these immunological changes imply a clinical benefit. Follow up studies of immune variables versus clinical effects during combined therapy of MS with IFN-b+G A are ongoing.
Distinct roles for IP-10/C XC L10 in three animal models, Theiler’s virus infection, EA E, and MHV infection, for multiple sclerosis: implication of differing roles for IP-10
Authors: Tsunoda Ikuo , Lane Thomas E , Blackett Jana , Fujinami Robert S
Published: February 2004

Theiler’s murine encephalomyelitis virus (TMEV) causes demyelination with inflammation of the central nervous system (C NS) in mice and is used as an animal model for multiple sclerosis (MS). Interferon-g inducible protein-10 kDa (IP-10) is a C XC chemokine and a chemoattractant for C XC R3+ T cells. IP-10 mRNA is expressed in the C NS during TMEV infection. However, administration of anti-IP- 10 serum caused no difference in clinical signs, inflammation, demyelination, virus persistence or anti-virus antibody response in TMEV infection, while levels of virus specific and autoreactive lymphoproliferation increased. This likely reflects a difference in the pathogenesis of TMEV infection from that of two other animal models for MS, mouse hepatitis virus infection and experimental allergic encephalomyelitis (EAE), where blocking of IP-10 resulted in clinical and histological improvement with suppression of antigen specific lymphoproliferation. In this review, we compare and contrast the roles of IP-10 between the three animal models for MS, and discuss the relevance to MS patients with different clinical courses.