bluuebunny/crossref_metadata_2025 huggingface dataset:
A biomechanical comparison of kyphoplasty using a balloon bone tamp versus an expandable polymer bone tamp in a deer spine model
Authors: Seel E. H. , Davies E. M.
Published: February 2007

We performed a biomechanical study to compare the augmentation of isolated fractured vertebral bodies using two different bone tamps. Compression fractures were created in 21 vertebral bodies harvested from red deer after determining their initial strength and stiffness, which was then assessed after standardised bipedicular vertebral augmentation using a balloon or an expandable polymer bone tamp.

The median strength and stiffness of the balloon bone tamp group was 6.71 kN (sd 2.71) and 1.885 kN/mm (sd 0.340), respectively, versus 7.36 kN (sd 3.43) and 1.882 kN/mm (sd 0.868) in the polymer bone tamp group. The strength and stiffness tended to be greater in the polymer bone tamp group than in the balloon bone tamp group, but this difference was not statistically significant (strength p > 0.8, and stiffness p = 0.4).
Treatment for developmental dysplasia of the hip using the Pavlik harness
Authors: Nakamura J. , Kamegaya M. , Saisu T. , Someya M. , Koizumi W. , Moriya H.
Published: February 2007

We reviewed the medical records of 115 patients with 130 hips with developmental dysplasia with complete dislocation in the absence of a neuromuscular disorder, spontaneous reduction with a Pavlik harness, and a minimum of 14 years’ follow-up. The mean age at the time of harness application was 4.8 months (1 to 12) and the mean time spent in the harness was 6.1 months (3 to 12). A total of 108 hips (83.1%) were treated with the harness alone and supplementary surgery for residual acetabular dysplasia, as defined by an acetabular index > 30°, was performed in 22 hips (16.9%).

An overall satisfactory outcome (Severin grade I or II) was achieved in 119 hips (91.5%) at a mean follow-up of 16 years (14 to 32) with a follow-up rate of 75%. Avascular necrosis of the femoral head was noted in 16 hips (12.3%), seven of which (44%) underwent supplementary surgery and nine (56%) of which were classified as satisfactory. The acetabular index was the most reliable predictor of residual acetabular dysplasia.
Proximal scaphoid rib graft arthroplasty
Authors: Veitch S. , Blake S. M. , David H.
Published: February 2007

We prospectively reviewed 14 patients with deficiency of the proximal pole of the scaphoid who were treated by rib osteochondral replacement arthroplasty.

Improvement in wrist function occurred in all except one patient with enhanced grip strength, less pain and maintenance of wrist movement. In 13 patients wrist function was rated as good or excellent according to the modified wrist function score of Green and O’Brien. The mean pre-operative score of 54 (35 to 80) rose to 79 (50 to 90) at review at a mean of 64 months (27 to 103). Carpal alignment did not deteriorate in any patient and there were no cases of nonunion or significant complications.

This procedure can restore the mechanical integrity of the proximal pole of the scaphoid satisfactorily and maintain wrist movement while avoiding the potential complications of alternative replacement arthroplasty techniques and problems associated with vascularised grafts and salvage techniques.
Unicameral bone cysts
Authors: Cho H. S. , Oh J. H. , Kim H.-S. , Kang H. G. , Lee S. H.
Published: February 2007

Open surgery is rarely justified for the initial treatment of a unicameral bone cyst, but there is some debate concerning the relative effectiveness of closed methods. This study compared the results of steroid injection with those of autologous bone marrow grafting for the treatment of unicameral bone cysts. Between 1990 and 2001, 30 patients were treated by steroid injection and 28 by grafting with autologous bone marrow. The overall success rates were 86.7% and 92.0%, respectively (p > 0.05). The success rate after the initial procedure was 23.3% in the steroid group and 52.0% in those receiving autologous bone marrow (p < 0.05), and the respective cumulative success rates after second injections were 63.3% and 80.0% (p > 0.05). The mean number of procedures required was 2.19 (1 to 5) and 1.57 (1 to 3) (p < 0.05), the mean interval to healing was 12.5 months (4 to 32) and 14.3 months (7 to 36) (p > 0.05), and the rate of recurrence after the initial procedure was 41.7% and 13.3% in the steroid and in the autologous bone marrow groups, respectively (p < 0.05).

Although the overall rates of success of both methods were similar, the steroid group had higher recurrence after a single procedure and required more injections to achieve healing.
Wear analysis of failed acetabular polyethylene
Authors: Chuter G. S. J. , Cloke D. J. , Mahomed A. , Partington P. F. , Green S. M.
Published: February 2007

There are many methods for analysing wear volume in failed polyethylene acetabular components. We compared a radiological technique with three recognised ex vivo methods of measurement.

We tested 18 ultra-high-molecular-weight polyethylene acetabular components revised for wear and aseptic loosening, of which 13 had pre-revision radiographs, from which the wear volume was calculated based upon the linear wear. We used a shadowgraph technique on silicone casts of all of the retrievals and a coordinate measuring method on the components directly. For these techniques, the wear vector was calculated for each component and the wear volume extrapolated using mathematical equations. The volumetric wear was also measured directly using a fluid-displacement method. The results of each technique were compared.

The series had high wear volumes (mean 1385 mm3; 730 to 1850) and high wear rates (mean 205 mm3/year; 92 to 363). There were wide variations in the measurements of wear volume between the radiological and the other techniques. Radiograph-derived wear volume correlated poorly with that of the fluid-displacement method, co-ordinate measuring method and shadowgraph methods, becoming less accurate as the wear increased. The mean overestimation in radiological wear volume was 47.7% of the fluid-displacement method wear volume.

Fluid-displacement method, coordinate measuring method and shadowgraph determinations of wear volume were all better than that of the radiograph-derived linear measurements since they took into account the direction of wear. However, only radiological techniques can be used in vivo and remain useful for monitoring linear wear in the clinical setting.

Interpretation of radiological measurements of acetabular wear must be done judiciously in the clinical setting. In vitro laboratory techniques, in particular the fluid-displacement method, remain the most accurate and reliable methods of assessing the wear of acetabular polyethylene.
Use of the reverse shoulder prosthesis for the treatment of failed hemiarthroplasty in patients with glenohumeral arthritis and rotator cuff deficiency
Authors: Levy J. C. , Virani N. , Pupello D. , Frankle M.
Published: February 2007

We report the use of the reverse shoulder prosthesis in the revision of a failed shoulder hemiarthroplasty in 19 shoulders in 18 patients (7 men, 11 women) with severe pain and loss of function. The primary procedure had been undertaken for glenohumeral arthritis associated with severe rotator cuff deficiency.

Statistically significant improvements were seen in pain and functional outcome. After a mean follow-up of 44 months (24 to 89), mean forward flexion improved by 26.4° and mean abduction improved by 35°. There were six prosthesis-related complications in six shoulders (32%), five of which had severe bone loss of the glenoid, proximal humerus or both. Three shoulders (16%) had non-prosthesis related complications.

The use of the reverse shoulder prosthesis provides improvement in pain and function for patients with failure of a hemiarthroplasty for glenohumeral arthritis and rotator cuff deficiency. However, high rates of complications were associated with glenoid and proximal humeral bone loss.
MultifocalProteus mirabilisosteomyelitis requiring bilateral amputation in an HIV-positive patient
Authors: Petsatodis G. , Symeonidis P. D. , Karataglis D. , Pournaras J.
Published: February 2007

We present a rare case of multifocal Proteus mirabilis osteomyelitis in an HIV-positive patient. Despite the patient’s good immune status as assessed by her CD4 cell count and the aggressive treatment, she eventually underwent bilateral above-knee amputations to eradicate the infection. Multifocal Proteus mirabilis osteomyelitis can have an unpredictable clinical course with a severe outcome in HIV-positive patients.
Sciatic nerve injury caused by pre-operative intraneural injection of local anaesthetic during total hip replacement
Authors: Uppal H. S. , Gwilym S. E. , Crawfurd E. J. P. , Birch R.
Published: February 2007

We report a case of iatrogenic sciatic nerve injury caused by pre-operative intraneural injection of local anaesthetic at total hip replacement. To our knowledge, this is unreported in the orthopaedic literature. We consider sacral nerve blockade in patients undergoing total hip replacement to be undesirable and present guidelines for the management of peri-operative sciatic nerve injury.
Outcome after corrective osteotomy for malunited fractures of the forearm sustained in childhood
Authors: van Geenen R. C. I. , Besselaar P. P.
Published: February 2007

We analysed the operative technique, morbidity and functional outcome of osteotomy and plate fixation for malunited fractures of the forearm sustained in childhood.

A total of 20 consecutive patients underwent corrective osteotomy of 21 malunited fractures at a mean age of 12 years (4 to 25). The mean time between the injury and the osteotomy was 30 months (2 to 140).

After removal of the plate, one patient suffered transient dysaesthesia of the superficial radial nerve. The mean gain in the range of movement was 85° (20° to 140°). The interval between injury and osteotomy, and the age at osteotomy significantly influenced the functional outcome (p = 0.011 and p = 0.004, respectively).

Malunited fractures of the forearm sustained in childhood can be adequately treated by osteotomy and plate fixation with excellent functional results and minimal complications. In the case of established malunion it is advisable to perform corrective osteotomy without delay.
RhBMP-7 accelerates the healing in distal tibial fractures treated by external fixation
Authors: Ristiniemi J. , Flinkkilä T. , Hyvönen P. , Lakovaara M. , Pakarinen H. , Jalovaara P.
Published: February 2007

External fixation of distal tibial fractures is often associated with delayed union. We have investigated whether union can be enhanced by using recombinant bone morphogenetic protein-7 (rhBMP-7).

Osteoinduction with rhBMP-7 and bovine collagen was used in 20 patients with distal tibial fractures which had been treated by external fixation (BMP group). Healing of the fracture was compared with that of 20 matched patients in whom treatment was similar except that rhBMP-7 was not used.

Significantly more fractures had healed by 16 (p = 0.039) and 20 weeks (p = 0.022) in the BMP group compared with the matched group. The mean time to union (p = 0.002), the duration of absence from work (p = 0.018) and the time for which external fixation was required (p = 0.037) were significantly shorter in the BMP group than in the matched group. Secondary intervention due to delayed healing was required in two patients in the BMP group and seven in the matched group.

RhBMP-7 can enhance the union of distal tibial fractures treated by external fixation.
Near-fatal air embolus during arthrography of the hip in a baby aged four months
Authors: Lamdan R. , Sadun A. , Shamir M. Y.
Published: February 2007

We describe a near-fatal event, probably due to air embolism, following an air arthrogram for developmental hip dysplasia in a baby aged four months. The sequence of events and the subsequent treatment are described. There is little information about this complication in the literature. The presumed mechanism and alternative methods for confirmation of placement of the needle are discussed. We no longer use air arthrography in children.
Restoration of shoulder function and elbow flexion by nerve transfer for poliomyelitis-like paralysis caused by enterovirus 71 infection
Authors: Funahashi S. , Nagano A. , Sano M. , Ogihara H. , Omura T.
Published: February 2007

We report the case of an eight-month-old girl who presented with a poliomyelitis-like paralysis in her left upper limb caused by enterovirus 71 infection. She recovered useful function after nerve transfers performed six months after the onset of paralysis. Early neurotisation can be used successfully in the treatment of poliomyelitis-like paralysis in children.
A modified tibial tubercle osteotomy for patellar maltracking
Authors: Koëter S. , Diks M. J. F. , Anderson P. G. , Wymenga A. B.
Published: February 2007

An abnormal lateral position of the tibial tuberosity causes distal malalignment of the extensor mechanism of the knee and can lead to lateral tracking of the patella causing anterior knee pain or objective patellar instability, characterised by recurrent dislocation. Computer tomography is used for a precise pre-operative assessment of the tibial tubercle-trochlear groove distance. A distance of more than 15 mm is considered to be pathological and an indication for surgery in symptomatic patients.

In a prospective study we performed a subtle transfer of the tibial tuberosity according to the information gained from the pre-operative CT scan. This method was applied to two groups of patients, those with painful lateral tracking of the patella, and those with objective patellar instability. We evaluated the clinical results in 30 patients in each group. The outcome was documented at 3, 12 and 24 months using the Lysholm scale, the Kujala score, and a visual analogue pain score.

Post-operatively, all but one patient in the instability group who had a patellar dislocation requiring further surgery reported good improvement with no further subluxation or dislocation. All patients in both groups had a marked improvement in pain and functional score. Two patients sustained a tibial fracture six and seven weeks after surgery. One patient suffered a per-operative fracture of the tibial tubercle which later required further fixation.

If carefully performed, this type of transfer of the tibial tubercle appears to be a satisfactory technique for the treatment of patients with an increased tibial tubercle-trochlear groove distance and who present with symptoms related to lateral maltracking of the patella.
Total hip replacement after intra-articular injection of local anaesthetic and steroid
Authors: Chitre A. R. , Fehily M. J. , Bamford D. J.
Published: February 2007

Intra-articular injections of steroid into the hip are used for a variety of reasons in current orthopaedic practice. Recently their safety prior to ipsilateral total hip replacement has been called into question owing to concerns about deep joint infection.

We undertook a retrospective analysis of all patients who had undergone local anaesthetic and steroid injections followed by ipsilateral total hip replacement over a five-year period. Members of the surgical team, using a lateral approach to the hip, performed all the injections in the operating theatre using a strict aseptic technique. The mean time between injection and total hip replacement was 18 months (4 to 50). The mean follow-up after hip replacement was 25.8 months (9 to 78), during which time no case of deep joint sepsis was found.

In our series, ipsilateral local anaesthetic and steroid injections have not conferred an increased risk of infection in total hip replacement. We believe that the practice of intra-articular local anaesthetic and steroid injections to the hip followed by total hip replacement is safer than previously reported.
Gradual joint distraction of post-traumatic flexion contracture of the proximal interphalangeal joint by a mini-external fixator
Authors: Houshian S. , Chikkamuniyappa C. , Schroeder H.
Published: February 2007

We present the outcome of the treatment of chronic post-traumatic contractures of the proximal interphalangeal joint by gradual distraction correction using an external fixator. A total of 30 consecutive patients with a mean age of 34 years (17 to 54) had distraction for a mean of 16 days (10 to 22). The fixator was removed after a mean of 29 days (16 to 40). Assessment at a mean of 34 months (18 to 54) after completion of treatment showed that the mean active range of movement had significantly increased by 63° (30° to 90°; p < 0.001). The mean active extension gained was 47° (30° to 75°).

Patients aged less than 40 years fared slightly better with a mean gain in active range of movement of 65° (30° to 90°) compared with those aged more than 40 years, who had a mean gain in active range of movement of 55° (30° to 70°) but the difference was not statistically significant (p = 0.148).

The use of joint distraction to correct chronic flexion contracture of the proximal interphalangeal joint is a minimally-invasive and effective method of treatment.
Blood and urine metal ion levels in young and active patients after Birmingham hip resurfacing arthroplasty
Authors: Daniel J. , Ziaee H. , Pradhan C. , Pynsent P. B. , McMinn D. J. W.
Published: February 2007

This is a longitudinal study of the daily urinary output and the concentrations in whole blood of cobalt and chromium in patients with metal-on-metal resurfacings over a period of four years.

Twelve-hour urine collections and whole blood specimens were collected before and periodically after a Birmingham hip resurfacing in 26 patients. All ion analyses were carried out using a high-resolution inductively-coupled plasma mass spectrometer. Clinical and radiological assessment, hip function scoring and activity level assessment revealed excellent hip function.

There was a significant early increase in urinary metal output, reaching a peak at six months for cobalt and one year for chromium post-operatively. There was thereafter a steady decrease in the median urinary output of cobalt over the following three years, although the differences are not statistically significant. The mean whole blood levels of cobalt and chromium also showed a significant increase between the pre-operative and one-year post-operative periods. The blood levels then decreased to a lower level at four years, compared with the one-year levels. This late reduction was statistically significant for chromium but not for cobalt.

The effects of systemic metal ion exposure in patients with metal-on-metal resurfacing arthroplasties continue to be a matter of concern. The levels in this study provide a baseline against which the in vivo wear performance of newer bearings can be compared.
Visualisation of the pisotriquetral joint through standard portals for arthroscopy of the wrist
Authors: Arya A. P. , Kulshreshtha R. , Kakarala G. K. , Singh R. , Compson J. P.
Published: February 2007

Disorders of the pisotriquetral joint are well recognised as the cause of pain on the ulnar side of the wrist. The joint is not usually examined during routine arthroscopy because it is assumed to have a separate joint cavity to the radiocarpal joint, although there is often a connection between the two.

We explored this connection during arthroscopy and in fresh-frozen cadaver wrists and found that in about half of the cases the pisotriquetral joint could be visualised through standard wrist portals. Four different types of connection were observed between the radiocarpal joint and the pisotriquetral joint. They ranged from a complete membrane separating the two, to no membrane at all, with various other types of connection in between.

We recommend that inspection of the pisotriquetral joint should be a part of the protocol for routine arthroscopy of the wrist.
Percutaneous fixation of the pelvic ring
Authors: Giannoudis P. V. , Tzioupis C. C. , Pape H.-C. , Roberts C. S.
Published: February 2007

With the development of systems of trauma care the management of pelvic disruption has evolved and has become increasingly refined. The goal is to achieve an anatomical reduction and stable fixation of the fracture. This requires adequate visualisation for reduction of the fracture and the placement of fixation. Despite the advances in surgical approach and technique, the functional outcomes do not always produce the desired result. New methods of percutaneous treatment in conjunction with innovative computer-based imaging have evolved in an attempt to overcome the existing difficulties. This paper presents an overview of the technical aspects of percutaneous surgery of the pelvis and acetabulum.
Metacarpophalangeal joint dislocation of the thumb in children
Authors: Maheshwari R. , Sharma H. , Duncan R. D. D.
Published: February 2007

There are few reports describing dislocation of the metacarpophalangeal joint of the thumb in children. This study describes the clinical features and outcome of 37 such dislocations and correlates the radiological pattern with the type of dislocation.

The mean age at injury was 7.3 years (3 to 13). A total of 33 children underwent closed reduction (11 under general anaesthesia). Four needed open reduction in two of which there was soft-tissue interposition. All cases obtained a good result. There was no infection, recurrent dislocation or significant stiffness.

So-called ‘simple complete’ dislocations that present with the classic radiological finding of the joint at 90° dorsal angulation may be ‘complex complete’ injuries and require open reduction.
A randomised controlled trial comparing bipolar hemiarthroplasty with total hip replacement for displaced intracapsular fractures of the femoral neck in elderly patients
Authors: Blomfeldt R. , Törnkvist H. , Eriksson K. , Söderqvist A. , Ponzer S. , Tidermark J.
Published: February 2007

The best treatment for the active and lucid elderly patient with a displaced intracapsular fracture of the femoral neck is still controversial. Randomised controlled trials have shown that a primary total hip replacement is superior to internal fixation as regards the need for secondary surgery, hip function and health-related quality of life. Despite good results achieved with total hip replacement in this group, most orthopaedic surgeons still advocate hemiarthroplasty for this injury. We studied 120 patients with a mean age of 81 years (70 to 90) with an acute displaced intracapsular fracture of the femoral neck. They were randomly allocated to be treated with either a bipolar hemiarthroplasty or total hip replacement. Outcome measurements included peri-operative data, general and hip-specific complications, hip function and health-related quality of life. The patients were reviewed at four and 12 months.

The duration of surgery was longer in the total hip replacement group (102 minutes (70 to 151)) versus 78 minutes (43 to 131) (p < 0.001), and the intra-operative blood loss was increased 460 ml (100 to 1100) versus 320 ml (50 to 850) (p < 0.001), but there were no differences between the groups regarding any complications or mortality. There were no dislocations in either group. Hip function measured by the Harris hip score was significantly better in the total hip replacement group at both follow-up periods (p = 0.011 and p < 0.001, respectively). The health-related quality of life measure was in favour of the total hip replacement group but did not reach statistical significance (p = 0.818 at four months and p = 0.636 at 12 months).

These results indicate that a total hip replacement provides better function than a bipolar hemiarthroplasty as soon as one year post-operatively, without increasing the complication rate. We recommend total hip replacement as the primary treatment for this group of patients.
Changes in the bone mineral density in the acetabulum and proximal femur after cementless total hip replacement
Authors: Kim Y.-H. , Yoon S.-H. , Kim J.-S.
Published: February 2007

Our aim in this prospective study was to compare the bone mineral density (BMD) around cementless acetabular and femoral components which were identical in geometry and had the same alumina modular femoral head, but differed in regard to the material of the acetabular liners (alumina ceramic or polyethylene) in 50 patients (100 hips) who had undergone bilateral simultaneous primary total hip replacement. Dual energy X-ray absorptiometry scans of the pelvis and proximal femur were obtained at one week, at one year, and annually thereafter during the five-year period of the study.

At the final follow-up, the mean BMD had increased significantly in each group in acetabular zone I of DeLee and Charnley (20% (15% to 26%), p = 0.003), but had decreased in acetabular zone II (24% (18% to 36%) in the alumina group and 25% (17% to 31%) in the polyethylene group, p = 0.001). There was an increase in the mean BMD in zone III of 2% (0.8% to 3.2%) in the alumina group and 1% (0.6% to 2.2%) in the polyethylene group (p = 0.315). There was a decrease in the mean BMD in the calcar region (femoral zone 7) of 15% (8% to 24%) in the alumina group and 14% (6% to 23%) in the polyethylene group (p < 0.001). The mean bone loss in femoral zone 1 of Gruen et al was 2% (1.1% to 3.1%) in the alumina group and 3% (1.3% to 4.3%) in the polyethylene group (p = 0.03), and in femoral zone 6, the mean bone loss was 15% (9% to 27%) in the alumina group and 14% (11% to 29%) in the polyethylene group compared with baseline values. There was an increase in the mean BMD on the final scans in femoral zones 2 (p = 0.04), 3 (p = 0.04), 4 (p = 0.12) and 5 (p = 0.049) in both groups.

There was thus no significant difference in the bone remodelling of the acetabulum and femur five years after total hip replacement in those two groups where the only difference was in the acetabular liner.
Total knee replacement in haemophilic arthropathy
Authors: Rodriguez-Merchan E. C.
Published: February 2007

The results of primary total knee replacement performed on a group of haemophiliac patients in a single institution by the same surgeon using the same surgical technique and prosthesis are reported.

A total of 35 primary replacements in 30 patients were carried out between 1996 and 2005 and were reviewed retrospectively. The mean age of the patients was 31 years (24 to 42) and the mean follow-up was for 7.5 years (1 to 10). There were 25 patients with haemophilia A and five with haemophilia B. The HIV status and CD4 count were recorded, and Knee Society scores determined. Two patients had inhibitors to the deficient coagulation factor.

There were no early wound infections and only one late deep infection which required a two-stage revision arthroplasty, with a good final result. The incidence of infection in HIV-positive and negative patients was thus similar. One knee in a patient with inhibitor had excessive bleeding due to a pseudoaneurysm which required embolisation. The results were excellent in 27 knees (77%), good in six (17%) and fair in two (6%). The survival rate at 7.5 years taking removal of the prosthesis for loosening or infection as the end-point was 97%.

The mechanical survival of total knee replacements in haemophiliacs is very good. Our results confirm that this is a reproducible procedure in haemophilia, even in HIV-positive patients with a CD4 count > 200 mm3 and those with inhibitors. Our rate of infection was lower than previously reported. This could be due to better control of the HIV status with highly active anti-retroviral therapy and the use of antibiotic-loaded cement.
Nesiritide Compared with Milrinone for Cardiac Surgery
Authors: Blais Danielle M
Published: February 2007

Management of patients with low cardiac output syndromes is difficult. Current therapies (ie, inotropes) have associated adverse effects and have not been shown to impact clinical outcomes such as decreased mortality or length of stay. Patients unable to recover from low cardiac output states have end organ damage, increased lengths of stay, increased hospital costs, and readmissions. Nesiritide has been suggested as an alternative or adjunct medication to treat cardiac surgery patients. Recent trials have provided information on the effects of some of these agents on clinical outcomes including respiratory failure, length of stay, and mortality.
Effects of competition on students' self‐efficacy in vicarious learning
Authors: Chan Joanne C. Y. , Lam Shui‐fong
Published: February 2007

Background

Vicarious learning is one of the fundamental sources of self‐efficacy that is frequently employed in educational settings. However, little research has investigated the effects of competition on students' writing self‐efficacy when they engage in vicarious learning.

Aim

This study compared the effects of competitive and non‐competitive classrooms on students' writing self‐efficacy when they engaged in vicarious learning.

Sample

The participants were 71 grade 7 students in Hong Kong.

Method

Using prior writing performance for stratified random sampling, students were assigned either to a competitive or a non‐competitive classroom. Students learned how to compose similes and metaphors in Chinese.

Results

In the competitive classroom, students' self‐efficacy decreased when they engaged in vicarious learning. In the non‐competitive classroom, students' self‐efficacy did not show a significant change when they engaged in vicarious learning.

Conclusion

The findings suggested that when students engaged in vicarious learning in a competitive classroom, their self‐efficacy might be threatened. Implications for efforts to design constructive context for vicarious learning are discussed.
Stability analysis in K‐means clustering
Authors: Steinley Douglas
Published: February 2007

This paper develops a new procedure, called stability analysis, for K‐means clustering. Instead of ignoring local optima and only considering the best solution found, this procedure takes advantage of additional information from a K‐means cluster analysis. The information from the locally optimal solutions is collected in an object by object co‐occurrence matrix. The co‐occurrence matrix is clustered and subsequently reordered by a steepest ascent quadratic assignment procedure to aid visual interpretation of the multidimensional cluster structure. Subsequently, measures are developed to determine the overall structure of a data set, the number of clusters and the multidimensional relationships between the clusters.
Avoidant coping as a mediator between appearance‐related victimization and self‐esteem in young Australian adolescents
Authors: Lodge J. , Feldman S. S.
Published: February 2007

Peer victimization, especially appearance‐related bullying, is a highly stressful experience for a young person and is associated with significant negative outcomes. Perhaps, the most common consequence of peer victimization in adolescence is lowered self‐esteem. Evidence supports the role of low self‐esteem as a non‐specific risk factor and high self‐esteem as a protective factor in the development of mental disorders and social problems in adolescence. Moreover, the literature indicates a robust negative relationship between avoidant coping (i.e. distracting oneself, wishing the situation would go away) and psychological well‐being. In this paper, we test a mediational model of the associations between appearance‐related victimization, avoidance coping and self‐esteem in young Australian adolescents. Boys (N = 194) and girls (N = 185) with a mean age of 11 years completed measures assessing self‐esteem, appearance‐related victimization and styles of coping. The results showed that avoidant coping partially mediates the association between appearance‐related bullying problems and self‐esteem among young adolescents. This finding provides a specific target for psychosocial interventions in schools.
Fine motor skills and mathematics achievement in East Asian American and European American kindergartners and first graders
Authors: Luo Zupei , Jose Paul E. , Huntsinger Carol S. , Pigott Therese D.
Published: February 2007

This study examined whether fine motor skills were related to the initial scores and growth rate of mathematics achievement in American kindergartners and first graders. Participants were 244 East Asian American and 9,816 European American children from the US‐based Early Childhood Longitudinal Study (ECLS‐K). To control sampling bias, two subsamples of European Americans were matched to the East Asian American sample by socio‐economic status or fine motor skills, using propensity score matching. Results showed that East Asian American children possessed more advanced mathematics achievement and fine motor skills. The construct of fine motor skills significantly predicted mathematics achievement over time, and further, it significantly mediated the relationship between ethnic group status and mathematics achievement.
It has certainly been good just to talk: An interpretative phenomenological analysis of coping with myocardial infarction
Authors: Hogg Natalie M. , Garratt Vanessa , Shaw Samantha K. , Tagney Jenny
Published: February 2007

Objectives.The experience of a myocardial infarction (MI), its potential meaning and consequences arouse a high level of emotional responsiveness in the individual. Researchers to date have argued that implementing adaptive coping strategies is necessary for emotional adjustment. This study aimed to advance coping research by providing more detailed insight into middle‐aged men's personal experiences of coping with MI and the meaning they ascribe to these experiences.

Design.Interpretative Phenomenological Analysis (IPA) was used to conduct an in‐depth study of a small sample of patients who had suffered their first MI.

Method.Semi‐structured interviews were conducted with six men within 6 months of their first MI. Verbatim transcripts of these interviews were analysed using IPA.

Results.Three superordinate themes emerged, which are described under the headings of ‘Difficulty in Reflecting’, ‘Needing to Talk’ and ‘Back to Normal’.

Conclusions.Participants seemed to share difficulties in reflecting on their coping strategies and the concept of coping generally, but were keen to talk about specific events in relation to the MI. The findings suggest that cardiac rehabilitation needs to focus on individual priorities for recovery. Providing opportunities for patients to talk through their experiences individually may be an important aspect of such care. Further research is needed to investigate the challenges that patients confront and the support they require post‐MI.
Income Tax Accounting Policy Choice: Exposure Draft Responses and the Early Adoption Decision by Canadian Companies*
Authors: Bujaki Merridee L. , McConomy Bruce J.
Published: February 2007

We extend prior literature through a detailed examination of the relationship between lobbying behavior and subsequent accounting standard adoption timing, using changes to a Canadian accounting standard with a prolonged transition period. We develop a model linking lobbying and adoption timing. We test hypotheses based on recontracting costs, information production costs, efforts to manage investor perceptions, and corporate governance practices to assess the ability of these factors to explain corporations' choice of adoption timing. We examine responses to the Income Taxes exposure draft using content analysis to identify trends in lobbying behavior. We evaluate the accounting standard adoption decision for Toronto Stock Exchange (TSE) 300 firms using a LOGIT model. Our findings indicate that early adoption appears to be most prevalent for firms that benefit from improved financial statement performance. In contrast, late adopters tend to be firms that have lobbied standard‐setters regarding the out‐of‐pocket costs of the standard and that rate highly on certain corporate governance measures.
The Primacy of “Present Fairly” in the Auditor's Report*
Authors: Zeff Stephen A.
Published: February 2007

In this paper, the author examines the historical evolution in the United States of the use of the term “present fairly” in the auditor's report, as well as the experience and arguments in the United States and Canada regarding the use of a “two‐part” opinion in the report. He then develops an argument for the adoption of a “two‐part” opinion, decoupling “present fairly” from conformity with generally accepted accounting principles, which would place primary emphasis on “present fairly".
Financial Times Business School Rankings: A Nontraditional Assurance Case in Three Parts*
Authors: Davies Andrea B. , Salterio Steven E.
Published: February 2007

The Financial Times of London (FT) is a business newspaper, with daily editions published in the United Kingdom, continental Europe, the United States, and Asia, and an estimated daily readership of 10 million people. In 1999 the FT began to publish a ranking of what it considered to be the top business schools in the world. Since their inception, these rankings have become increasingly relied upon by potential students and business school administrators worldwide. The FT's ranking is unique compared with other rankings because of its special international focus. Given the prominence of these rankings and the FT's position as a well‐respected business newspaper, the question of providing assurance over the business school rankings that the FT provides is particularly challenging.
Recent Changes in the Regulation of Financial Markets and Reporting in Canada*
Authors: Carnaghan Carla , Gunz Sally P.
Published: February 2007

The regulation of financial reporting and financial markets has undergone significant change in both the United States and Canada since 2000. In Canada, the regulatory regime is particularly complex and politically controversial, with much speculation about possible future directions. This paper's purpose is to explain the current regulatory environment as it stands in mid‐2006 to assist those who teach or conduct research in this domain. On the basis of a review of existing regulations and related studies, this paper first provides an explanation of the major jurisdictional issues that affect financial reporting and regulation in Canada, including identifying the roles of the key players. Second, it identifies specific reporting changes that might be of particular relevance to prospective capital market researchers. Where relevant, comparisons are made with regulatory provisions in the United States, because the majority of capital markets research concerns U.S. securities exchanges regulation, and the Canadian regulations themselves often refer to U.S. regulations as a point of comparison.

We find that the lack of a single national securities regulator in Canada and overlaps in federal and provincial jurisdiction and among regulatory bodies mean there is a large range of players involved in financial markets regulation. Ongoing efforts to improve integration include the new passport system, improved harmonization of securities regulation, and consideration of mergers between some of the involved organizations. Other changes have led to a greater emphasis in Canada on the regulation of continuous disclosure and corporate governance than was previously the case. Changes in specific reporting regulations and guidelines since 2002 have generally increased the amount of disclosure.
The Role of Correlations in Direction and Contrast Coding in the Primary Visual Cortex
Authors: Montani Fernando , Kohn Adam , Smith Matthew A. , Schultz Simon R.
Published: February 2007

The spiking activity of nearby cortical neurons is not independent. Numerous studies have explored the importance of this correlated responsivity for visual coding and perception, often by comparing the information conveyed by pairs of simultaneously recorded neurons with the sum of information provided by the respective individual cells. Pairwise responses typically provide slightly more information so that encoding is weakly synergistic. The simple comparison between pairwise and summed individual responses conflates several forms of correlation, however, making it impossible to judge the relative importance of synchronous spiking, basic tuning properties, and stimulus-independent and stimulus-dependent correlation. We have applied an information theoretic approach to this question, using the responses of pairs of neurons to drifting sinusoidal gratings of different directions and contrasts that have been recorded in the primary visual cortex of anesthetized macaque monkeys. Our approach allows us to break down the information provided by pairs of neurons into a number of components. This analysis reveals that, although synchrony is prevalent and informative, the additional information it provides frequently is offset by the redundancy arising from the similar tuning properties of the two cells. Thus coding is approximately independent with weak synergy or redundancy arising, depending on the similarity in tuning and the temporal precision of the analysis. We suggest that this would allow cortical circuits to enjoy the stability provided by having similarly tuned neurons without suffering the penalty of redundancy, because the associated information transmission deficit is compensated for by stimulus-dependent synchrony.
Dissociation between CA3–CA1 Synaptic Plasticity and Associative Learning in TgNTRK3 Transgenic Mice
Authors: Sahún Ignasi , Delgado-García José María , Amador-Arjona Alejandro , Giralt Albert , Alberch Jordi , Dierssen Mara , Gruart Agnès
Published: February 2007

Neurotrophins and their cognate receptors might serve as feedback regulators for the efficacy of synaptic transmission. We analyzed mice overexpressing TrkC (TgNTRK3) for synaptic plasticity and the expression of glutamate receptor subunits. Animals were conditioned using a trace [conditioned stimulus (CS), tone; unconditioned stimulus (US), shock] paradigm. A single electrical pulse presented to the Schaffer collateral–commissural pathway during the CS–US interval evoked a monosynaptic field EPSP (fEPSP) at ipsilateral CA1 pyramidal cells. In wild types, fEPSP slopes increased across conditioning sessions and decreased during extinction, being linearly related to learning evolution. In contrast, fEPSPs in TgNTRK3 animals reached extremely high values, not accompanied with a proportionate increase in their learning curves. Long-term potentiation evoked in conscious TgNTRK3 was also significantly longer lasting than in wild-type mice. These functional alterations were accompanied by significant changes in NR1 and NR2B NMDA receptor subunits, with no modification of NR1Ser 896or NR1Ser 897phosphorylation. No changes of AMPA and kainate subunits were detected. Results indicate that the NT-3/TrkC cascade could regulate synaptic transmission and plasticity through modulation of glutamatergic transmission at the CA3–CA1 synapse.
Orientation-Selective Adaptation to Illusory Contours in Human Visual Cortex
Authors: Montaser-Kouhsari Leila , Landy Michael S. , Heeger David J. , Larsson Jonas
Published: February 2007

Humans can perceive illusory or subjective contours in the absence of any real physical boundaries. We used an adaptation protocol to look for orientation-selective neural responses to illusory contours defined by phase-shifted abutting line gratings in the human visual cortex. We measured functional magnetic resonance imaging (fMRI) responses to illusory-contour test stimuli after adapting to an illusory-contour adapter stimulus that was oriented parallel or orthogonal to the test stimulus. We found orientation-selective adaptation to illusory contours in early (V1 and V2) and higher-tier visual areas (V3, hV4, VO1, V3A/B, V7, LO1, and LO2). That is, fMRI responses were smaller for test stimuli parallel to the adapter than for test stimuli orthogonal to the adapter. In two control experiments using spatially jittered and phase-randomized stimuli, we demonstrated that this adaptation was not just in response to differences in the distribution of spectral power in the stimuli. Orientation-selective adaptation to illusory contours increased from early to higher-tier visual areas. Thus, both early and higher-tier visual areas contain neurons selective for the orientation of this type of illusory contour.
Prefrontal Neural Correlates of Memory for Sequences
Authors: Averbeck Bruno B. , Lee Daeyeol
Published: February 2007

The sequence of actions appropriate to solve a problem often needs to be discovered by trial and error and recalled in the future when faced with the same problem. Here, we show that when monkeys had to discover and then remember a sequence of decisions across trials, ensembles of prefrontal cortex neurons reflected the sequence of decisions the animal would make throughout the interval between trials. This signal could reflect either an explicit memory process or a sequence-planning process that begins far in advance of the actual sequence execution. This finding extended to error trials such that, when the neural activity during the intertrial interval specified the wrong sequence, the animal also attempted to execute an incorrect sequence. More specifically, we used a decoding analysis to predict the sequence the monkey was planning to execute at the end of the fore-period, just before sequence execution. When this analysis was applied to error trials, we were able to predict where in the sequence the error would occur, up to three movements into the future. This suggests that prefrontal neural activity can retain information about sequences between trials, and that regardless of whether information is remembered correctly or incorrectly, the prefrontal activity veridically reflects the animal's action plan.
Sleep Deprivation Increases A1Adenosine Receptor Binding in the Human Brain: A Positron Emission Tomography Study
Authors: Elmenhorst David , Meyer Philipp T. , Winz Oliver H. , Matusch Andreas , Ermert Johannes , Coenen Heinz H. , Basheer Radhika , Haas Helmut L. , Zilles Karl , Bauer Andreas
Published: February 2007

It is currently hypothesized that adenosine is involved in the induction of sleep after prolonged wakefulness. This effect is partially reversed by the application of caffeine, which is a nonselective blocker of adenosine receptors. Here, we report that the most abundant and highly concentrated A1subtype of cerebral adenosine receptors is upregulated after 24 h of sleep deprivation. We used the highly selective A1adenosine receptor (A1AR) radioligand [18F]CPFPX ([18F]8-cyclopentyl-3-(3-fluoropropyl)-1-propylxanthine) and quantitative positron emission tomography to assess cerebral A1ARs before and after sleep deprivation in 12 healthy volunteers and a control group (n= 10) with regular sleep. In sleep deprived subjects, we found an increase of the apparent equilibrium total distribution volume in a region-specific pattern in all examined brain regions with a maximum increase in the orbitofrontal cortex (15.3%;p= 0.014). There were no changes in the control group with regular sleep. This is the first molecular imaging study that providesin vivoevidence for an A1AR upregulation in cortical and subcortical brain regions after prolonged wakefulness, indicating that A1AR expression is contributing to the homeostatic sleep regulation.