bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of injection conditions and exhaust gas recirculation in a high-speed direct-injection diesel engine operating with a late split injection
Authors: Benajes J , Molina S , Novella R , DeRudder K 
Published: April 2008

This paper describes an investigation on low-temperature combustion in a small single-cylinder high-speed direct-injection diesel engine. This engine is representative of turbocharged passenger car diesel engines equipped with a particulate trap and an oxidation catalyst. A medium-load engine operation condition was evaluated using two fuel injection events near top dead centre and high levels of exhaust gas recirculation. The combustion was characterized by extremely low emission of nitrogen oxides (of the order of 10—15ppm) and low combustion noise. The study was carried out by means of a design of experiments, consisting of four factors varied on three levels according to a Box—Behnken design. This Box—Behnken design was extended with validation points, allowing all factors to be studied independently in a parametric approach. Additionally, some relevant two-factor interactions have been studied. The investigated factors were the exhaust gas recirculation rate, the combustion phasing, the injection pressure, and the dwell between the split injections. The results show how it is possible to achieve very low levels of nitrogen oxides and low combustion noise with reasonable fuel consumption, smoke emissions, hydrocarbons, and carbon monoxide emissions, with injection and combustion just after top dead centre.
Improvement in the assessment of wear of total knee replacements using coordinate-measuring machine techniques
Authors: Blunt L A , Bills P J , Jiang X-Q , Chakrabarty G 
Published: April 2008

Total joint replacement is one of the most common elective surgical procedures performed worldwide, with an estimate of 1.5×106 operations performed annually. Currently joint replacements are expected to function for 10–15 years; however, with an increase in life expectancy, and a greater call for knee replacement due to increased activity levels, there is a requirement to improve their function to offer longer-term improved quality of life for patients. Wear analysis of total joint replacements has long been an important means in determining failure mechanisms and improving longevity of these devices. The effectiveness of the coordinate-measuring machine (CMM) technique for assessing volumetric material loss during simulated life testing of a replacement knee joint has been proved previously by the present authors. The purpose of the current work is to present an improvement to this method for situations where no pre-wear data are available. To validate the method, simulator tests were run and gravimetric measurements taken throughout the test, such that the components measured had a known wear value. The implications of the results are then discussed in terms of assessment of joint functionality and development of standardized CMM-based product standards. The method was then expanded to allow assessment of clinically retrieved bearings so as to ascertain a measure of true clinical wear.
Sensitivity of proximal femoral stiffness and areal bone mineral density to changes in bone geometry and density
Authors: Pisharody S , Phillips R , Langton C M 
Published: April 2008

Areal bone mineral density (aBMD) is the most common surrogate measurement for assessing the bone strength of the proximal femur associated with osteoporosis. Additional factors, however, contribute to the overall strength of the proximal femur, primarily the anatomical geometry. Finite element analysis (FEA) is an effective and widely used computer-based simulation technique for modelling mechanical loading of various engineering structures, providing predictions of displacement and induced stress distribution due to the applied load. FEA is therefore inherently dependent upon both density and anatomical geometry. FEA may be performed on both three-dimensional and two-dimensional models of the proximal femur derived from radiographic images, from which the mechanical stiffness may be predicted. It is examined whether the outcome measures of two-dimensional FEA, two-dimensional, finite element analysis of X-ray images (FEXI), and three-dimensional FEA computed stiffness values of the proximal femur are more sensitive than aBMD to changes in trabecular bone density and femur geometry. It is assumed that if an outcome measure follows known trends with changes in density and geometric parameters, then an increased sensitivity will be indicative of an improved prediction of bone strength. All three outcome measures increased non-linearly with trabecular bone density, increased linearly with cortical shell thickness and neck width, decreased linearly with neck length, and were relatively insensitive to neck-shaft angle. For femoral head radius, aBMD was relatively insensitive, with two-dimensional FEXI and three-dimensional FEA demonstrating a non-linear increase and decrease in sensitivity respectively. For neck anteversion, aBMD decreased non-linearly, whereas both two-dimensional FEXI and three-dimensional FEA demonstrated a parabolic-type relationship, with the maximum stiffness being achieved at an angle of approximately 15°. Multi-parameter analysis showed that all three outcome measures demonstrated their highest sensitivity to a change in cortical thickness. When changes in all input parameters were considered simultaneously, three and two-dimensional FEA had statistically equal sensitivities (0.41 ± 0.20 and 0.42 ± 0.16 respectively, p= ns) that were significantly higher than the sensitivity of aBMD (0.24 ± 0.07; p=0.014 and 0.002 for three-dimensional and two-dimensional FEA respectively). This simulation study suggests that since mechanical integrity and FEA are inherently dependent on anatomical geometry, FEXI stiffness, being derived from conventional two-dimensional radiographic images, may provide an improvement in the prediction of bone strength of the proximal femur than currently provided by aBMD.
Understanding the differences between the wear of metal-on-metal and ceramic-on-metal total hip replacements
Authors: Figueiredo-Pina C G , Yan Y , Neville A , Fisher J 
Published: April 2008

Hip simulator studies have been carried out extensively to understand and test artificial hip implants in vitro as an efficient alternative to obtaining long-term results in vivo. Recent studies have shown that a ceramic-on-metal material combination lowers the wear by up to 100 times in comparison with a typical metal-on-metal design. The reason for this reduction remains unclear and for this reason this study has undertaken simple tribometer tests to understand the fundamental material loss mechanisms in two material combinations: metal-on-metal and ceramic-on-ceramic. A simple-configuration reciprocating pin-on-plate wear study was performed under open-circuit potential (OCP) and with applied cathodic protection (CP) in a serum solution using two tribological couples: firstly, cobalt—chromium (Co—Cr) pins against Co—Cr plates; secondly, Co—Cr pins against alumina (Al2O3) plates. The pin and plate surfaces prior to and after testing were examined by profilometry and scanning electron microscopy. The results showed a marked reduction in wear when CP was applied, indicating that total material degradation under the OCP condition was attributed to corrosion processes. The substitution of the Co—Cr pin with an Al2O3 plate also resulted in a dramatic reduction in wear, probably due to the reduction in the corrosion—wear interactions between the tribological pair.
Do Clinicians Always Maximize Patient Outcomes? A Conjoint Analysis of Preferences for Carotid Artery Testing
Authors: Sassi Franco , Mckee Martin 
Published: April 2008

Objectives The value clinicians place on diagnostic information is subject to psychological influences and systematic biases, but there is limited evidence of how these factors may affect patients’ health outcomes. We assessed the relative value attached by experienced clinicians to different diagnostic test characteristics and how their preferences relate to patient outcomes, focusing on strategies for testing symptomatic patients for carotid artery stenosis. Methods Using conjoint analysis, experienced neurologists and vascular surgeons ranked 10 diagnostic strategies defined in terms of four characteristics. Clinicians’ preferences were analysed using an ordered probit model and compared with those obtained using a risk neutral expected value (EV) model developed to predict the consequences of each strategy as if the clinicians’ sole goal were to optimize patient outcome. Results were tested for internal consistency and robustness to key model assumptions. Results Preferences for positive predictive value (PPV), relative to negative predictive value (NPV), elicited from the clinicians diverged substantially from those estimated by the EV model based on 5-year stroke-free survival (ratios of 20.8 and 232.8, respectively). Conversely, preferences for NPV, relative to test morbidity, from the two models matched closely. Conclusions Clinicians attached substantially more importance to the PPV of carotid artery tests than would be justified by ther impact on patient outcomes. Cognitive errors and attitudes to risk are likely to play an important role in explaining this finding. This study casts doubts on the validity of common assumptions made in the evaluation of health interventions, and in clinical and policy decisions.
Modelling the Expected Net Benefits of Interventions to Reduce the Burden of Medication Errors
Authors: Karnon Jonathan , Mcintosh Aileen , Dean Joanne , Bath Peter , Hutchinson Allen , Oakley Jeremy , Thomas Nicky , Pratt Peter , Freeman-Parry Louise , Karsh Ben-Tzion , Gandhi Tejal , Tappenden Paul 
Published: April 2008

Objectives The aim of this study is to estimate the potential costs and benefits of three key interventions (computerized physician order entry [CPOE], additional ward pharmacists and bar coding) to help prioritize research to reduce medication errors. Methods A generic model structure was developed to describe the incidence and impacts of medication errors in hospitals. The model follows pathways from medication error points at alternative stages of the medication pathway through to the outcomes of undetected errors. The model was populated from a systematic review of the medication errors literature combined with novel probabilistic calibration methods. Cost ranges were applied to the interventions, the treatment of preventable adverse drug events (pADEs), and the value of the health lost as a result of an ADE. Results The model predicts annual health service costs of between £0.3 million and £1 million for the treatment of pADEs in a 400-bed acute hospital in the UK. Including only health service costs, it is uncertain whether any of the three interventions will produce positive net benefits, particularly if high intervention costs are assumed. When the monetary value of lost health is included, all three interventions have a high probability of producing positive net benefits with a mean estimate of around £31.5 million for CPOE over a five-year time horizon. Conclusions The results identify the potential cost-effectiveness of interventions aimed at medication errors, as well as identifying key drivers of cost-effectiveness that should be specifically addressed in the design of primary evaluations of medication error interventions.
Patient Choice in General Practice: The Implications of Patient Satisfaction Surveys
Authors: Robertson Ruth , Dixon Anna , Le Grand Julian 
Published: April 2008

Objectives To identify factors that explain patient satisfaction with general practice physicians and hence that may drive patients’ choice of practice. Methods Logistic regression analysis of English National Health Service national patient survey data is used to identify the aspects of general practice care that are associated with high levels of overall satisfaction among patients. Results Confidence and trust in the doctor is the most important factor in explaining the variation in overall patient satisfaction (predicting 82% of satisfaction levels accurately). The seven variables relating to the relationship between patient and doctor have stronger explanatory power than other aspects of the general practitioner (GP) experience. The variables with the lowest overall predictive power are whether the patient was told how long they would have to wait in the surgery (72%), the length of time they had to wait after their appointment time (74%) and ability to get through to the surgery on the phone (74%). Conclusions Patients value the quality of their relationship with their doctor more than the appearance of the surgery, accessibility of appointments and their experience in the waiting room. This suggests that, if current restrictions on choice of GP were removed, we would in theory expect a patient's choice to be driven by the quality of the doctor-patient relationship. Once a patient establishes a good relationship with a GP, however, we might expect them to be loyal and therefore unlikely to change practice unless the relationship with the doctor breaks down. Although relationship factors are important to the satisfaction of patients, it is not clear that they will lead large numbers of people to change their GP.
The Quality of Mixed Methods Studies in Health Services Research
Authors: O'cathain Alicia , Murphy Elizabeth , Nicholl Jon 
Published: April 2008

Objectives To assess the quality of mixed methods studies in health services research (HSR). Methods We identified 118 mixed methods studies funded by the Department of Health in England between 1994 and 2004, and obtained proposals and/or final reports for 75. We applied a set of quality questions to both the proposal and report of each study, addressing the success of the study, the mixed methods design, the individual qualitative and quantitative components, the integration between methods and the inferences drawn from completed studies. Results Most studies were completed successfully. Researchers mainly ignored the mixed methods design and described only the separate components of a study. There was a lack of justification for, and transparency of, the mixed methods design in both proposals and reports, and this had implications for making judgements about the quality of individual components in the context of the design used. There was also a lack of transparency of the individual methods in terms of clear exposition of data collection and analysis, and this was more a problem for the qualitative than the quantitative component: 42% (19/45) versus 18% (8/45) of proposals (p 5 0.011). Judgements about integration could rarely be made due to the absence of an attempt at integration of data and findings from different components within a study. Conclusions The HSR community could improve mixed methods studies by giving more consideration to describing and justifying the design, being transparent about the qualitative component, and attempting to integrate data and findings from the individual components.
Evidence-Based Medicine and Patient Choice: The Case of Heart Failure Care
Authors: Sanders Tom , Harrison1 Stephen , Checkland1 Kath 
Published: April 2008

Objectives The implementation of evidence-based medicine and policies aimed at increasing user involvement in health care decisions are central planks of contemporary English health policy. Yet they are potentially in conflict. Our aim was to explore how clinicians working in the field of heart failure resolve this conflict. Methods Qualitative semi-structured interviews were carried out with health professionals who were currently caring for patients with heart failure, and observations were conducted at one dedicated heart failure clinic in northern England. Results While clinicians acknowledged that patients’ ideas and preferences should be an important part of treatment decisions, the widespread acceptance of an evidence-based clinical protocol for heart failure among the clinic doctors significantly influenced the content and style of the consultation. Conclusion Evidence-based medicine was used to buttress professional authority and seemed to provide an additional barrier to the adoption of patient-centred clinical practice.
How to Write a Good Research Paper
Authors: Light Kate , Glanville Julie , Stirk Lisa 
Published: April 2008

There are numerous websites that aim to help students write research papers but it is necessary to look a little further to find websites that are relevant to researchers wishing to publish in peer-reviewed journals. Here we review sites that address scientific writing style, present guidelines for reporting trials and other studies, and provide access to submission requirements for individual journals. Additionally, we list some other relevant sites. If you would like to alert readers to useful web pages or suggest topics for this column, please send details to:
Assessing the Consequences of a Channel Switch
Authors: Chen Xinlei (Jack) , John George , Narasimhan Om 
Published: April 2008

Switching marketing channels is an expensive and sticky decision. While a number of theories suggest efficiency and strategic differences between channels, there is virtually no work on combining these ideas into an empirically workable methodology to assess the impact of a channel switch. In this study, we undertake to close this gap with an empirical study of the sports drink market, featuring competing producers and heterogeneous channels. We estimate demand and cost parameters for a number of alternative models of competitive interaction and use these estimates to study the switching of Gatorade from its extant (independent wholesaler) channel to the direct store delivery (DSD) channel belonging to Pepsi. Our initial results indicate the following: Pepsi should switch Gatorade to the DSD channel only if (i) the switch decreases Gatorade's manufacturing cost by at least 14%, or (ii) the switch increases the share of profit it can obtain by at least 13%, or (iii) the switch enhances demand by the equivalent of a price cut of 4.96¢ for a 32-ounces package. Absent these increases, Pepsi should not switch. Our methodology and results speak to both managers contemplating a channel switch and antitrust authorities faced with the task of evaluating the consequences of a change in vertical structure.
Interpretation of Complex Modulus Test Results for Asphalt-Aggregate Mixes
Authors: Levenberg Eyal , Shah Ayesha 
Published: April 2008

Abstract
In this paper, a slightly different approach than usual is suggested to interpret complex modulus results for asphalt-aggregate mixes. Similar to current/common methods, the proposed analysis “forces” the test data to comply with thermo-rheological simplicity and linear viscoelastic (solid) behavior. However, unlike current methods, use is made of both dynamic modulus and phase angle data to obtain a master curve along with the corresponding time-temperature shifting. This is done by assuming a mathematical expression for the relaxation spectrum instead of an equation for the dynamic modulus master curve. Consequently, better compliance with linear viscoelastic theory is a-priori ensured for all subsequent analyses. Moreover, using the proposed method, conversion of the test results from the frequency domain to the time domain arises as a natural and simple outcome of the procedure which does not require sophisticated inversion techniques that are known to be computationally problematic. Complex modulus test results obtained for three different asphalt mixes are presented and analyzed in order to demonstrate the applicability of the proposed method.
Services and Service Composition – An Introduction (Services und Service Komposition – Eine Einführung)
Authors: Dustdar Shahram , Papazoglou Mike P. 
Published: April 2008

Summary
In this overview paper, we discuss the basic principles underlying service-oriented computing in general, and (Web) services in particular. We discuss the important differences between (Web) services and Web applications and other models in Internet computing. Finally, we discuss where we see the future research challenges in the area of service composition.
Business Process Standards – Current Landscape (Landkarte aktueller Standards zur Beschreibung von Geschäftsprozessen: WS-BPEL, BPEL4People, BPEL-SPE, BPELJ, SCA)
Authors: Kloppmann Matthias , König Dieter , Pfau Gerhard 
Published: April 2008

Summary
The landscape of current specifications for the description of business processes consists of the Web Services Business Process Execution Language (WS-BPEL) as an adopted standard, and a number of functional extensions allowing for human interactions (BPEL4People), sub-processes with life-cycle coupling (BPEL-SPE), and Java integration (BPELJ). Also relevant for the assembly of portable, executable applications is the Service Component Architecture (SCA) which provides a model for service-based components complementing WS-BPEL. This paper provides an overview of the current business process standards landscape and its further evolution.
Quality of Service in SOA Environments. An Overview and Research Agenda (Quality of Service in SOA-Umgebungen)
Authors: Curbera Francisco , Khalaf Rania , Mukhi Nirmal 
Published: April 2008

Summary
Interoperability and componentization are the two defining characteristics of Service Oriented Architectures (SOA). From a middleware perspective this means standardized quality of service (QoS) protocols and QoS-rich service descriptions. This paper provides an architectural overview of quality of service issues in SOA environments and a review of open problems and current research directions.
Semantic Execution Environments for Semantics-Enabled SOA (Ausführungsumgebungen für eine um Semantik erweiterte SOA)
Authors: Norton Barry , Pedrinaci Carlos , Domingue John , Zaremba Michal 
Published: April 2008

Summary
Much recent work in SOA has concentrated on documenting reference architectures. In this paper we present on-going work on the establishment of such an architecture within the OASIS SEE TC, detailing how the benefits of semantic Web services can be applied to SOA and the role of semantic execution environments, such as the IRS and WSMX.