bluuebunny/crossref_metadata_2025_split huggingface dataset:
Objective assessment of a surgical trainee
Authors: Cheung Moon‐Tong , Yau Kelvin‐K. W. 
Published: March 2003

Background: Early assessment of surgical trainees in their training programme is essential. A strong subjective observer’s bias occurs when using the mentor assessment form. In‐service examinations and qualifying examinations are only valid measurements of the trainee’s knowledge of factual material. An objective method to assess a surgical trainee’s clinical performance is introduced in the present study.Methods: We examined the Generalized Linear Mixed Model statistical methodology to obtain standardized performance scores that would identify good and poor performers while taking into account the effects of patients’ risk factors. Data regarding the postappendectomy complication occurrence and operation duration were retrospectively collected for each trainee. These variables were analysed by applying logistic regression and proportional hazards regression models respectively. Standardized trainee scores were obtained as by‐products that measured the residual effect of surgeons’ performances after taking into account the effects of possible risk factors.Results: A total of 37 trainees were involved in 638 appendectomy operations from 1994 to 1997. Age, concurrent medical disease and presence of pus were significant risk factors associated with complication occurrence. Concurrent medical disease, presence of pus, operative findings of gangrenous or ruptured appendix as well as the experience of the surgeon had a significant effect on the operation duration. The present study identifies four trainees that displayed good clinical performance, and one trainee that displayed poor clinical performance of appendectomy.Conclusion: Our proposed method makes use of recently developed statistical methodology for predicting the effect of surgeons’ performance, taking into account variations in their case‐mix and their patients’ fitness. This approach may serve as a very powerful tool for early assessment of a trainee’s clinical proficiency, and may also have implications for the future assessment of a surgeon’s clinical standard.
Management of orbitozygomatic fractures
Authors: Lynham Anthony J. , Monsour Frank N. T. , Chapman Pat J. 
Published: March 2003

Background:  Management of orbitozygomatic fractures forms part of the scope of practice of many oral and maxillofacial surgeons. As aspects of management vary among surgeons who treat such injuries, this confidential study was undertaken to examine some of the protocols of Australian and New Zealand oral and maxillofacial surgeons.Results:  Eighty‐one per cent of the respondents treated orbitozygomatic fractures and on average, each treated approximately 24 cases per year. Also, about one in five cases required orbital floor exploration. Further, the preferred imaging baseline was computed tomography plus plain X‐rays, while the preferred implant materials for orbital floor reconstruction were autologous bone and resorbable membrane. The incidence of postoperative retrobulbar haemorrhage was estimated at approximately 1:1000.Conclusion:  Most oral and maxillofacial surgeons treat orbitozygomatic injuries as part of their surgical scope.
Management of liver trauma with implications for the rural surgeon
Authors: Wemyss‐Holden Simon A. , Bruening Martin , Launois Bernard , Maddern Guy J. 
Published: March 2003

Background:  The majority of patients with liver trauma can be managed conservatively. However, the unstable patient requires emergency laparotomy to control bleeding. Controversy exists regarding the primary surgical management of these injuries. This is of particular relevance for the isolated rural general surgeon.Methods:  The literature was reviewed by searching MEDLINE databases from 1966 to the present time. The majority of the evidence presented is level 3, with interpretations and recommendations based on the experience of the senior authors.Results:  In the majority of patients, conservative management remains the mainstay of treatment. However, haemodynamic ­instability requires urgent laparotomy. Perihepatic packing should be used to arrest bleeding. Primary anatomical resection is rarely indicated, especially in non‐specialist centres.Conclusion:  In the remote rural setting, severe liver trauma remains a daunting condition for the general surgeon to manage. Primary surgical treatment should be perihepatic packing, stabilization and urgent transfer; there is no place for primary anatomical resection outside specialist units.
Novel strategy to stop cigarette smoking by surgical patients: Pilot study in a preadmission clinic
Authors: Haile Melanie J. , Wiggers John H. , D. Spigelman Allan , Knight Jenny , Considine Robyn J. , Moore Karen 
Published: March 2003

Background:  Evidence‐based guidelines suggest that all services, wards and clinics within hospitals consider smoking status a vital sign and routinely provide cessation care. Despite this, such opportunities are currently under‐utilized. The aim of the present pilot study was to determine the potential effectiveness, feasibility and acceptability of computer delivery of smoking cessation advice to surgical preadmission patients.
Methods:  All smokers attending a non‐cardiac surgical preadmission clinic at the John Hunter Hospital, New South Wales, completed a brief computerized smoking cessation intervention programme. Nine months following completion of the programme, patients completed a follow‐up telephone interview that assessed their smoking status and the acceptability of the programme.
Results:  At follow up, 22 of the 37 participants (60.0%) reported that they had stopped smoking prior to their surgery 9 months previously. Of the 37 participants at follow up, five reported that they were no longer smokers at that time, a cessation rate of 13.5%. Among those patients still smoking, a trend toward smoking fewer cigarettes was evident. Of the 56 smokers at baseline, all completed the computerized smoking cessation programme, with an average completion time of 21 min. A large majority of the smokers (80%) and non‐smokers (88%) found that the provision of smoking cessation advice by the computer was appropriate and acceptable. Extrapolation of the results to a full year suggests a cost per quitter of $443.
Conclusions:  An interactive computerized smoking cessation programme is an acceptable and feasible method of routinely encouraging surgical preadmission clinic patients to stop or reduce their smoking. Further development and testing of the efficacy of this approach is required.
Wound blisters post hip surgery: A prospective trial comparingdressings
Authors: Lawrentschuk Nathan , Falkenberg Michael P. , Pirpiris Marinis 
Published: March 2003

Introduction:  Wound blisters are formed in the epidermis adjacent to surgicalincisions and are a significant cause of morbidity following hipsurgery. This study was designed to compare two commonly used primarydressings, namely a nonadherent absorbable (NAA) dressing and paraffintulle gras (PTG). Monitoring for the subsequent development of woundblisters in the epidermis adjacent to the surgical incision wasthen undertaken.Methods:  The present study was performed in the setting of a prospective,randomised trial of 50 consecutive patients undergoing hip surgery.It was assumed there would be no difference in the development ofblisters between the dressing groups. The alternative hypothesiswas that PTG would, because of its properties, provide less frictionin the epidermis and contribute to fewer wound blisters.Results:  A statistically significant difference (P = 0.0028)between the two dressing groups was observed with the NAA group developingblisters in 17 (64%) patients and the PTG group in onlytwo (8%) of the patients.Conclusion:  The present study would suggest that PTG produces fewer woundblisters following hip surgery when compared to the NAA type asa primary dressing.
Measurement of fatigue crack growth in large compact tension specimens using an AC magnetic field method
Authors: Austin J. 
Published: March 2003

ABSTRACTFatigue crack growth rate data are required in order to carry out a numerical analysis of the fatigue performance of complex structural components. These data are obtained by measuring crack growth in standard fracture mechanics specimens. A new method for measuring fatigue crack growth in compact tension specimens has been developed. The technique is based on the measurement of the surface magnetic fields produced when passing a high‐frequency alternating current through the specimen. Fatigue crack growth data recorded using this method indicated an accuracy of ±0.02 mm when compared with optical measurements. The technique is suitable for computer‐controlled operation and could easily be applied to other standard specimen geometries.
An interpretation of theCtparameter for increasing load conditions
Authors: Lee J. H. , Kim Y. J. , Yoon K. B. 
Published: March 2003

The prior assessment equations forCt , which is a well‐known fracture parameter for characterizing creep and creep–fatigue crack growth rates, have applicability to constant loading conditions only. However, crack growth due to creep can also occur under varying load conditions during a fatigue cycle when the loading (or unloading) rate is slow enough such that creep deformation can occur near the crack tip. Hence, the applicability of theCtparameter should be extended to varying load conditions.In this study, a method of extending the use of theCtparameter to increasing load conditions is proposed. Based on the concept of Irwin’s effective crack size, new equations for estimatingCtunder increasing load conditions are derived and denoted as (Ct )r . Finite element analyses were also performed under various increasing load conditions. From the analysis, the variation of (Ct )rvalues during the load rise period is obtained and the difference between the (Ct )rvalue at the end of the load rise period and theCtvalue at the beginning of the succeeding load hold period is discussed. A generalized creep–fatigue crack growth model which employs (Ct )ras a parameter characterizing crack growth rate during the rise time is also discussed.
Mean stress effects on low‐cycle fatigue for a precipitation‐hardening martensitic stainless steel in different tempers
Authors: Lin  , Chu  
Published: March 2003

ABSTRACTThe objective of this study is to investigate the effects of mean stress and ageing treatment on the low‐cycle fatigue (LCF) behaviour of a precipitation‐hardening martensitic stainless steel (PHMSS). Uniaxial LCF tests were conducted under strain control with three strain ratios, R = −1, 0 and 0.5 on specimens heat‐treated to three different tempers, i.e. solution‐annealed (SA), peak‐aged (H900) and overaged (H1150) conditions. Experimental results indicated that under a strain ratio of R = −1, specimens in H900 temper exhibited longer LCF lifetimes than those in SA and H1150 tempers. However, this advantage for H900 over SA and H1150 tempers disappeared at higher strain ratios (R = 0 and 0.5) due to the greater sensitivity to mean stress effects in H900 temper. For a given temper at high strain amplitudes, the LCF lifetimes under the three applied strain ratios did not show significant differences as a result of the mean stress relaxation effect. However, at low strain amplitudes, cyclic loading at R = −1 generated longer LCF lifetimes in comparison to R = 0 and 0.5 due to the absence of detrimental tensile mean stress. LCF lifetime data obtained for the given PHMSSs under various combinations of strain ratio and heat treatment were well correlated with a strength‐normalized Smith–Watson–Topper (SWT) parameter in a log–log linear model.
Fatigue tolerant design of steel components based on the size of large inclusions
Authors: YATES J. R. , SHI G. , ATKINSON H. V. , SELLARS C. M. , ANDERSON C. W. 
Published: March 2003

ABSTRACTFatigue failures in high strength steel components often originate from large, brittle inclusions. The durability of the components is strongly dependent on the size of the inclusions and the magnitude of the local stresses caused by the applied loads. A successful design must consider both the size and the number of large inclusions as well as the stress distribution arising from the geometry and loading of the component. This paper presents a new approach to the safe fatigue design of steel components based on the size distribution of large inclusions in a component with a given stress distribution. The procedure is illustrated using the example of the stress distribution around a hole in a plate, with the size of large inclusions in a large volume of steel estimated by the Generalized Pareto Distribution (GPD) method. It is found that the single largest inclusion is unlikely to lie in a highly stressed volume, but that the more frequently occurring slightly smaller inclusions contribute more to the probability of a fatigue failure. Knowledge of the shape of the size distribution over a range of large sizes, not solely that of the largest size, is therefore essential. The new approach offers a quantitative measure of the improvement in durability to be expected from reduction of the design stress range of a component and from improvements in steel cleanness.
An engineering model for prediction of rolling contact fatigue of railway wheels
Authors: EKBERG A. , KABO E. , ANDERSSON H. 
Published: March 2003

ABSTRACTAn engineering model for rolling contact fatigue (RCF) of railway wheels is developed. Three well‐known types of fatigue in wheels – surface‐initiated fatigue, subsurface‐initiated fatigue and fatigue initiated at deep material defects – are accounted for. Fatigue impact is quantified by three fatigue indices expressed in analytical form. The model can easily be integrated in a multibody dynamics code without significantly increasing computational demands. A powerful tool for optimizing train–track configurations with respect to fatigue performance should result. In this paper, theoretical foundations, benefits and limitations of the model are presented. An example of a postprocessing analysis of data from a dynamic simulation of train–track interaction is given.
Fatigue strength of die‐cast magnesium components
Authors: RENNER F. , ZENNER H. 
Published: March 2003

ABSTRACTThere is a commercial interest to extend the use of die‐cast magnesium from low stress applications, such as interior components of motor vehicles, to components carrying significant loads. In high stress applications it is the strength and fatigue properties of die‐cast magnesium alloys that limit their use. Manufacturing defects, such as microscopic shrink holes, pores and oxide inclusions, impair the strength of components under fatigue loads, but are unavoidable with present‐day magnesium casting technology. In the present study, the effects of different rib thicknesses and notch radii on the fatigue strength were investigated on realistic cast specimens with unmachined surfaces. The tests were performed on ribbed specimens of magnesium alloys AZ91 and AM60 under pulsating bending stress with a constant amplitude at a stress ratio R = 0. As indicated by the results of the investigation, the real material must be considered together with its defects in designing die‐cast magnesium components. For this purpose, the influence of defects must therefore be given a higher priority than the local stresses at the surface.
The effect of a corner radius on an asymptotic solution to the fretting of complete contacts including the plastic process zone
Authors: NAVARRO C. , HILLS D. A. , DOMINGUEZ J. 
Published: March 2003

ABSTRACTAn asymptotic elastic solution provides a good way of encapsulating the behaviour of the process zone at the edge of a complete contact. In this paper we examine the effect of a finite edge radius on the validity of such an approach, and provide clear recommendations on the tolerable edge radius if the asymptotic approach is to remain viable.
Stress concentration formula useful for any dimensions of shoulder fillet in a round bar under tension and bending
Authors: NODA N. A. , TAKASE Y. 
Published: March 2003

ABSTRACTIn this work stress concentration factors (SCFs), Kt for a round bar with a fillet are considered on the basis of exact solutions, now available for special cases, and accurate numerical results. Then, a convenient Kt formula useful for any dimensions of the fillet is proposed. The conclusions can be summarised as follows: (i) For the limiting cases of deep (d) and shallow (s) fillet, the body force method is used to calculate the Kt values. Then, the formula are obtained as Ktd and Kts. (ii) On the one hand, upon comparison of Kt and Ktd, it is found that Kt is nearly equal to Ktd if the fillet is deep or blunt. (iii) On the other hand, if the fillet is sharp or shallow, Kt is mainly controlled by Kts and the fillet depth. (iv) The fillet shape is classified into several groups according to the fillet radius and fillet depth. Then the least squares method is applied for calculation of Kt/Ktd and Kt/Kts. (v) Finally, a convenient formula is proposed that is useful for any dimensions of fillet in a round bar. The formula give SCFs with less than 1% error in most cases for any dimensions of fillet under tension and bending.
Allee effect makes possible patchy invasion in a predator–prey system
Authors: Petrovskii Sergei V. , Morozov Andrew Y. , Venturino Ezio 
Published: March 2003

AbstractThe dynamics of interacting ecological populations results from the interplay between various deterministic and stochastic factors and this is particularly the case for the phenomenon of biological invasion. Whereas the spread of invasive species via propagation of a population front was shown to appear as a result of deterministic processes, the spread via formation, interaction and movement of separate patches has been recently attributed to the influence of environmental stochasticity. An appropriate understanding of the comparative importance of deterministic and stochastic mechanisms is still lacking, however. In this paper, we show that the patchy invasion appears to be possible also in a fully deterministic predator–prey model as a result of the Allee effect.
Natural enemy diversity and pest control: patterns of pest emergence with agricultural intensification
Authors: Wilby Andrew , Thomas Matthew B. 
Published: March 2003

AbstractConcern over declining biodiversity and the implications for continued provision of ecosystem services has led, recently, to intense research effort to describe relationships between biodiversity and ecosystem functioning. Here we extend this effort to the relationship between natural enemy species diversity and natural pest control. From simple modelled food‐webs and simulations of natural enemy species loss we derive specific predictions concerning the effect of herbivore life‐history traits, such as life‐cycle type and concealment, on the shape (reflecting diversity effects) and variance (reflecting species composition effects) of the relationship between natural enemy diversity and pest‐control. We show that these predictions are consistent with the emergence of different pest types following intensification of rice production in Asia. We suggest that basic biological insights can help define the structure of ecological processes and allow more accurate predictions of the effect of species loss on the delivery of ecosystem services.
Penguins as oceanographers unravel hidden mechanisms of marine productivity
Authors: Charrassin Jean‐Benoît , Park Young‐Hyang , Maho Yvon Le , Bost Charles‐André 
Published: March 2003

ABSTRACTA recent concept for investigating marine ecosystems is to employ diving predators as cost‐effective, autonomous samplers of environmental parameters (such as sea‐temperature). Using king penguins during their foraging trips at sea, we obtained an unprecedented high resolution temperature map at depth off the Kerguelen Islands, Southern Ocean, a poorly sampled but productive area. We found clear evidence of a previously unknown subsurface tongue of cold water, flowing along the eastern shelf break. These new results provide a better understanding of regional water circulation and help explain the high primary productivity above the Kerguelen Plateau.
Resistance to a fungal pathogen and host plant specialization in the pea aphid
Authors: Ferrari Julia , Godfray H. Charles J. 
Published: March 2003

AbstractHerbivores that show host race formation on different plant species have proven to be valuable model systems for studying the evolution of specialization and speciation. Here, we use the pea aphid, Acyrthosiphon pisum, to investigate a possible link between specialization on two host plant species, Lotus uliginosus and Trifolium pratense, and resistance to a natural enemy, the fungal pathogen Erynia neoaphidis. Pea aphids collected on either plant species in the field showed in most cases poor survival on the alternate host plant. Furthermore, pea aphids specialized on T. pratense were very resistant to E. neoaphidis, whereas aphids specialized on L. uliginosus were susceptible. This susceptibility was not influenced by the actual food plant on which the assays were conducted. We discuss how selection from natural enemies may influence the process of specialization and race formation, and how specialization can affect the evolution of resistance.
Trophic control of grassland production and biomass by pathogens
Authors: Mitchell Charles E. 
Published: March 2003

AbstractCurrent theories of trophic regulation of ecosystem net primary production and plant biomass incorporate herbivores, but not plant pathogens. Obstacles to the incorporation of pathogens include a lack of data on pathogen effects on primary production, especially outside agricultural and forest ecosystems, and an apparent inability to quantify pathogen biomass. Here, I report the results of an experiment factorially excluding foliar fungal pathogens and insect herbivores from an intact grassland ecosystem. At peak in control plots, 8.9% of community leaf area was infected by pathogens. Disease reduction treatment dramatically increased root production and biomass by increasing leaf longevity and photosynthetic capacity. In contrast, herbivory reduction had no detectable effects at the ecosystem or leaf scale. Additionally, biomass of foliar fungal pathogens in the ecosystem was comparable with that of insect herbivores. These results identify pathogens as potential regulators of ecosystem processes and promote the incorporation of pathogens into trophic theory.