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Selected AbstractsHost,parasite interactions and competition between tubificid species in a benthic communityFRESHWATER BIOLOGY, Issue 8 2009L. C. STEINBACH ELWELL Summary 1. Parasites can be important determinants of host community structure while host community structure can influence the success of parasites, although both are often overlooked. In two laboratory experiments, we examined interactions among Myxobolus cerebralis syn Myxosoma cerebralis Höfer, the myxozoan parasite that causes salmonid whirling disease, and two coexisting tubificid species: Tubifex tubifex (Müller), which is the alternate host of the parasite, and Limnodrilus hoffmeisteri Claparède, which is not susceptible. In the first experiment, we examined T. tubifex infection prevalence when exposed to nine doses of spores. In the second experiment, we examined tubificid and parasite success under three spore doses when tubificids were combined in a response surface experimental design used to detect interactions among species. 2. The outcomes of interactions between tubificid species were complex. The number and biomass of offspring of both tubificid species were density dependent when in monoculture or in combination with the other species. Adult growth of T. tubifex was also density dependent in monoculture, but when L. hoffmeisteri replaced one-half of the T. tubifex in the high-density treatment, adult growth of T. tubifex was higher than in monoculture. Adult growth of L. hoffmeisteri was always density independent. Whether T. tubifex was exposed to the parasite or not did not change the outcome of these interactions. However, adult growth of T. tubifex, but not L. hoffmeisteri, was highest when M. cerebralis was present. 3. Infection prevalence of T. tubifex increased with increasing spore dose. Infection prevalence was lowest in the high-density T. tubifex monoculture and highest in the low-density T. tubifex monoculture and when T. tubifex was in combination with L. hoffmeisteri. 4. Both intraspecific and interspecific competition influenced tubificid success, but T. tubifex gained some competitive advantage through increased adult growth when in combination with L. hoffmeisteri. Whether T. tubifex was exposed to the parasite or not did not change the outcome of the interactions between the tubificid species. 5. The presence of L. hoffmeisteri did not decrease the prevalence of infection in T. tubifex, suggesting that parasite success was unaltered by the presence of this non-susceptible species. [source] The clinical effectiveness of nurse practitioners' management of minor injuries in an adult emergency department: a systematic reviewINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 1 2009Anne Wilson PhD, FRCNA Abstract Background, The increasing cost of healthcare in Australia demands changes in the way healthcare is delivered. Nurse practitioners have been introduced into specialty areas including emergency departments. Specific interventions are known to include the treatment and management of minor injuries, but little has been reported on their work. Objectives, Examine the best available evidence to determine the clinical effectiveness of emergency department nurse practitioners in the assessment, treatment and management of minor injuries in adults. Inclusion criteria, For inclusion studies had to include adult patients treated for minor injuries by nurse practitioners in emergency departments. All study designs were included. Search strategy, English language articles from 1986 onwards were sought using MEDLINE, CINAHL, Embase and Science Citation Index. Methodological quality, Two independent reviewers critically appraised the quality of the studies and extracted data using standardised tools. Data collection, Two independent reviewers assessed the eligibility of each study for inclusion into the review and the study design used. Where any disagreement occurred, consensus was reached by discussion with an independent researcher. Data synthesis, Studies were assessed for homogeneity by considering populations, interventions and outcomes. Where heterogeneity was present, synthesis was undertaken in a narrative format; otherwise a meta-analysis was conducted. For each outcome measure, results were tabulated by intervention type and discussed in a narrative summary. Results from randomised controlled trials were pooled in meta-analyses where appropriate. Results, Nine studies from a total of 55 participants met the inclusion criteria. Two were randomised controlled trials. Metasynthesis of research findings generated five synthesised findings derived from 16 study findings aggregated into seven categories. Evidence comparing the clinical effectiveness of nurse practitioners to mainstream management of minor injuries was fair to poor methodological quality. When comparable data were pooled, there were no significant differences (P < 0.05) between nurse practitioners and junior doctors. Conclusions, The results emphasise the need for more high-quality research using appropriate outcome measures in the area of clinical effectiveness of nurse practitioners, particularly interventions that improve outcomes for presentations to emergency departments and address issues of waiting and congestion. [source] Effectiveness of arthroscopic versus open surgical stabilisation for the management of traumatic anterior glenohumeral instabilityINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 2 2007Choong Ng BMedSci(Melb) Abstract Background, Anterior instability is a frequent complication following a traumatic glenohumeral dislocation. Frequently the underlying pathology associated with recurrent instability is a Bankart lesion. Surgical correction of Bankart lesions and other associated pathology is the key to successful treatment. Open surgical glenohumeral stabilisation has been advocated as the gold standard because of consistently low postoperative recurrent instability rates. However, arthroscopic glenohumeral stabilisation could challenge open surgical repair as the gold standard treatment for traumatic anterior glenohumeral instability. Objectives, Primary evidence that compared the effectiveness of arthroscopic versus open surgical glenohumeral stabilisation was systematically collated regarding best-practice management for adults with traumatic anterior glenohumeral instability. Search strategy, A systematic search was performed using 14 databases: MEDLINE, Cumulative Index of Nursing and Allied Health (CINAHL), Allied and Complementary Medicine Database (AMED), ISI Web of Science, Expanded Academic ASAP, Proquest Medical Library, Evidence Based Medicine Reviews, Physiotherapy Evidence Database, TRIP Database, PubMed, ISI Current Contents Connect, Proquest Digital Dissertations, Open Archives Initiative Search Engine, Australian Digital Thesis Program. Studies published between January 1984 and December 2004 were included in this review. No language restrictions were applied. Selection criteria, Eligible studies were those that compared the effectiveness of arthroscopic versus open surgical stabilisation for the management of traumatic anterior glenohumeral instability, which had more than 2 years of follow up and used recurrent instability and a functional shoulder questionnaire as primary outcomes. Studies that used non-anatomical open repair techniques, patient groups that were specifically 40 years or older, or had multidirectional instability or other concomitant shoulder pathology were excluded. Data collection and analysis, Two independent reviewers assessed the eligibility of each study for inclusion into the review, the study design used and its methodological quality. Where any disagreement occurred, consensus was reached by discussion with an independent researcher. Studies were assessed for homogeneity by considering populations, interventions and outcomes. Where heterogeneity was present, synthesis was undertaken in a narrative format; otherwise a meta-analysis was conducted. Results, Eleven studies were included in the review. Two were randomised controlled trials. Evidence comparing arthroscopic and open surgical glenohumeral stabilisation was of poor to fair methodological quality. Hence, the results of primary studies should be interpreted with caution. Observed clinical heterogeneity in populations and outcomes was highlighted and should be considered when interpreting the meta-analysis. Authors also used variable definitions of recurrent instability and a variety of outcome measures, which made it difficult to synthesise results. When comparable data were pooled, there were no significant differences (P > 0.05) between the arthroscopic and open groups with respect to recurrent instability rates, Rowe score, glenohumeral external rotation range and complication rates. Conclusions, Statistically, it appears that both surgical techniques are equally effective in managing traumatic anterior glenohumeral instability. In light of the methodological quality of the included studies, it is not possible to validate arthoscopic stabilisation to match open surgical stabilisation as the gold standard treatment. Further research using multicentred randomised controlled trials with sufficient power and instability-specific questionnaires with sound psychometric properties is recommended to build on current evidence. The choice of treatment should be based on multiple factors between the clinician and the patient. [source] Lack of evidence of the effectiveness of primary brachial plexus surgery for infants (under the age of two years) diagnosed with obstetric brachial plexus palsyINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 4 2006Andrea Bialocerkowski PhD M App Sc (Physio) M App Sc (Physio) Grad Dip Public Health Abstract Background, Obstetric brachial plexus palsy, which occurs in 1,3 per 1000 live births, results from traction and/or compression of the brachial plexus in utero, during descent through the birth canal or during delivery. This results in a spectrum of injuries that range in extent of damage and severity and can lead to a lifelong impairment and functional difficulties associated with the use of the affected upper limb. Most infants diagnosed with obstetric brachial plexus palsy receive treatment, such as surgery to the brachial plexus, physiotherapy or occupational therapy, within the first months of life. However, there is controversy regarding the most effective form of management. This review follows on from our previous systematic review which investigated the effectiveness of primary conservative management in infants with obstetric brachial plexus palsy. This systematic review focuses on the effects of primary surgery. Objectives, The objective of this review was to systematically assess and collate all available evidence on effectiveness of primary brachial plexus surgery for infants with obstetric brachial plexus palsy. Search strategy, A systematic literature search was performed using 13 databases: TRIP, MEDLINE, CINAHL, Web of Science, Proquest 5000, Evidence Based Medicine Reviews, Expanded Academic ASAP, Meditext, Science Direct, the Physiotherapy Evidence Database, Proquest Digital Dissertations, Open Archives Initiative Search Engine, the Australian Digital Thesis program. Those studies that were reported in English and published between July 1992 to June 2004 were included in this review. Selection criteria, Quantitative studies that investigated the effectiveness of primary brachial plexus surgery for infants with obstetric brachial plexus palsy were eligible for inclusion into this review. This excluded studies where infants were solely managed conservatively or with pharmacological agents, or underwent surgery for the management of secondary deformities. Data collection and analysis, Two independent reviewers assessed the eligibility of each study for inclusion into the review, the study design used and its methodological quality. Where any disagreement occurred, consensus was reached by discussion. Studies were also assessed for clinical homogeneity by considering populations, interventions and outcomes. Where heterogeneity was present, synthesis was undertaken in a narrative format. Results, Twenty-one studies were included in the review. Most were ranked low on the hierarchy of evidence (no randomised controlled trials were found), and most had only fair methodological quality. Surgical intervention was variable, as were the eligibility criteria for surgery, the timing of surgery and the outcome instruments used to evaluate the effect of surgery. Therefore, it is difficult to draw conclusions regarding the effectiveness of primary brachial plexus surgery for infants with obstetric brachial plexus palsy. Conclusions, Although there is a wealth of information regarding the outcome following primary brachial plexus surgery it was not possible to determine whether this treatment is effective in increasing functional recovery in infants with obstetric brachial plexus palsy. Further research is required to develop standardised surgical criteria, and standardised outcome measures should be used at specific points in time during the recovery process to facilitate comparison between studies. Moreover, comparison groups are required to determine the relative effectiveness of surgery compared with other forms of management. [source] Effectiveness of primary conservative management for infants with obstetric brachial plexus palsyINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 2 2005Andrea Bialocerkowski PhD MAppSc(Phty) GradDipPublicHealth Executive summary Background, Obstetric brachial plexus palsy, a complication of childbirth, occurs in 1,3 per 1000 live births internationally. Traction and/or compression of the brachial plexus is thought to be the primary mechanism of injury and this may occur in utero, during the descent through the birth canal or during delivery. This results in a spectrum of injuries that vary in severity, extent of damage and functional use of the affected upper limb. Most infants receive treatment, such as conservative management (physiotherapy, occupational therapy) or surgery; however, there is controversy regarding the most appropriate form of management. To date, no synthesised evidence is available regarding the effectiveness of primary conservative management for obstetric brachial plexus palsy. Objectives, The objective of this review was to systematically assess the literature and present the best available evidence that investigated the effectiveness of primary conservative management for infants with obstetric brachial plexus palsy. Search strategy, A systematic literature search was performed using 14 databases: TRIP, MEDLINE, CINAHL, AMED, Web of Science, Proquest 5000, Evidence Based Medicine Reviews, Expanded Academic ASAP, Meditext, Science Direct, Physiotherapy Evidence Database, Proquest Digital Dissertations, Open Archives Initiative Search Engine, Australian Digital Thesis Program. Those studies that were reported in English and published over the last decade (July 1992 to June 2003) were included in this review. Selection criteria, Quantitative studies that investigated the effectiveness of primary conservative management for infants with obstetric brachial plexus palsy were eligible for inclusion in this review. This excluded studies that solely investigated the effect of primary surgery for these infants, management of secondary deformities and the investigation of the effects of pharmacological agents, such as botulinum toxin. Data collection and analysis, Two independent reviewers assessed the eligibility of each study for inclusion into the review, the study design used and its methodological quality. Where any disagreement occurred, consensus was reached by discussion. Studies were assessed for clinical homogeneity by considering populations, interventions and outcomes. Where heterogeneity was present, synthesis was undertaken in a narrative format. Results, Eight studies were included in the review. Most were ranked low on the Hierarchy of Evidence (no randomised controlled trials were found), and had only fair methodological quality. Conservative management was variable and could consist of active or passive exercise, splints or traction. All studies lacked a clear description of what constituted conservative management, which would not allow the treatment to be replicated in the clinical setting. A variety of outcome instruments were used, none of which had evidence of validity, reliability or sensitivity to detect change. Furthermore, less severely affected infants were selected to receive conservative management. Therefore, it is difficult to draw conclusions regarding the effectiveness of conservative management for infants with obstetric brachial plexus palsy. Conclusions, There is scant, inconclusive evidence regarding the effectiveness of primary conservative intervention for infants with obstetric brachial plexus palsy. Further research should be directed to develop outcome instruments with sound psychometric properties for infants with obstetric brachial plexus palsy and their families. These outcome instruments should then be used in well-designed comparative studies. [source] Small-Sample Equating Using a Synthetic Linking FunctionJOURNAL OF EDUCATIONAL MEASUREMENT, Issue 4 2008Sooyeon Kim This study addressed the sampling error and linking bias that occur with small samples in a nonequivalent groups anchor test design. We proposed a linking method called the synthetic function, which is a weighted average of the identity function and a traditional equating function (in this case, the chained linear equating function). Specifically, we compared the synthetic, identity, and chained linear functions for various-sized samples from two types of national assessments. One design used a highly reliable test and an external anchor, and the other used a relatively low-reliability test and an internal anchor. The results from each of these methods were compared to the criterion equating function derived from the total samples with respect to linking bias and error. The study indicated that the synthetic functions might be a better choice than the chained linear equating method when samples are not large and, as a result, unrepresentative. [source] Analysis and optimization of low-pressure drop static mixersAICHE JOURNAL, Issue 9 2009Mrityunjay K. Singh Abstract Various designs of the so called Low-Pressure Drop (LPD) static mixer are analyzed for their mixing performance using the mapping method. The two types of LPD designs, the RR and RL type, show essentially different mixing patterns. The RL design provides globally chaotic mixing, whereas the RR design always yields unmixed regions separated by KAM boundaries from mixed regions. The crossing angle between the elliptical plates of the LPD is the key design parameter to decide the performance of various designs. Four different crossing angles from 90° to 160° are used for both the RR and RL designs. Mixing performance is computed as a function of the energy to mix, reflected in overall pressure drop for all designs. Optimization using the flux-weighted intensity of segregation versus pressure drop proves the existence of the best mixer with an optimized crossing angle. The optimized angle proves to be indeed the LLPD design used in practice: the RL-120 with , = 120°, although RL-140 , = 140° performs as good. Shear thinning shows minor effects on the mixing profiles, and the main optimization conclusions remain unaltered. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Information-seeking and mediated searching.JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 9 2002Part 1. Our project has investigated the processes of mediated information retrieval (IR) searching during human information-seeking processes to characterize aspects of this process, including information seekers' changing situational contexts; information problems; uncertainty reduction; successive searching, cognitive styles; and cognitive and affective states. The research has involved observational, longitudinal data collection in the United States and United Kingdom. Three questionnaires were used for pre- and postsearch interviews: reference interview, information seeker postsearch, and search intermediary postsearch questionnaires. In addition, the Sheffield team employed a fourth set of instruments in a follow-up interview some 2 months after the search. A total of 198 information seekers participated in a mediated on-line search with a professional intermediary using the Dialog Information Service. Each mediated search process was audio taped and search transaction log recorded. The findings are presented in four parts. Part I presents the background, theoretical framework, models, and research design used during the research. Part II is devoted to exploring changes in information seekers' uncertainty during the mediated process. Part III provides results related to successive searching. Part IV reports findings related to cognitive styles, individual differences, age and gender. Additional articles that discuss further findings from this complex research project, including: (1) an integrated model of information seeking and searching, (2) assessment of mediated searching, and (3) intermediary-information seeker communication, are in preparation and will be published separately. [source] Simulated experimental design used to define the characteristic curves of car shock-absorbersQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 2 2001G. Arcidiacono Abstract This paper introduces a special ,quality' parameter on automotive perspective, i.e. the quality index in order to measure the customer satisfaction with car manoeuvrability. In particular, it describes how the characteristic setting curves of a car shock-absorber can be optimized using subjective customer assessment of three categories of perception: handling, steering quality and ride-comfort. These, called manoeuvrability indices, were used to represent the assessment of customer satisfaction with car manoeuvrability. The characteristic curves for each shock-absorber setting were defined using parameters which uniquely determined their shape. Subsequent analysis was carried out using simulated experimental design which adopts a numeric model of vehicle simulation thereby enabling experimental costs to be reduced. This analysis made it possible to ascertain which setting parameter values provided the best compromise among the three categories of required performance. A codified method of optimization was then developed. This method, which includes the three categories of perception, will be extended to all new projects. Copyright © 2001 John Wiley & Sons, Ltd. [source] Morton's design of the early ether vaporisersANAESTHESIA, Issue 5 2002P. Desbarax Summary The exact design of the ether vaporiser used by William Morton on 16 October 1846 has remained uncertain with many contradictory reports. This article explores the known facts and speculates on the design used on that and subsequent occasions. [source] Evaluation of the Impeller Shroud Performance of an Axial Flow Ventricular Assist Device Using Computational Fluid DynamicsARTIFICIAL ORGANS, Issue 9 2010Boyang Su Abstract Generally, there are two types of impeller design used in the axial flow blood pumps. For the first type, which can be found in most of the axial flow blood pumps, the magnet is embedded inside the impeller hub or blades. For the second type, the magnet is embedded inside the cylindrical impeller shroud, and this design has not only increased the rotating stability of the impeller but has also avoided the flow interaction between the impeller blade tip and the pump casing. Although the axial flow blood pumps with either impeller design have been studied individually, the comparisons between these two designs have not been conducted in the literature. Therefore, in this study, two axial flow blood pumps with and without impeller shrouds were numerically simulated with computational fluid dynamics and compared with each other in terms of hydraulic and hematologic performances. For the ease of comparison, these two models have the same inner components, which include a three-blade straightener, a two-blade impeller, and a three-blade diffuser. The simulation results showed that the model with impeller shroud had a lower static pressure head with a lower hydraulic efficiency than its counterpart. It was also found that the blood had a high possibility to deposit on the impeller shroud inner surface, which greatly enhanced the possibility of thrombus formation. The blood damage indices in both models were around 1%, which was much lower than the 13.1% of the axial flow blood pump of Yano et al. with the corresponding experimental hemolysis of 0.033 g/100 L. [source] Vegetation impacts on near bank flowECOHYDROLOGY, Issue 4 2009Leslie Hopkinson Abstract Vegetation is an important component of stream restoration designs used to control streambank retreat, but vegetation effects on near bank flows need to be quantified. The goal of this research was to evaluate how three-dimensional velocity structure and turbulence characteristics vary with three vegetation treatments: tree, shrub and grass. A second order prototype stream (Tom's Creek in Blacksburg, Virginia, USA) with individual reaches dominated by each vegetation treatment was modelled in a research flume using a fixed-bed Froude-scale modelling technique. One model streambank of the prototype stream was constructed for each vegetation type and compared to a bare control (only grain roughness). Velocity profiles perpendicular to the flume model boundary were measured using a three-dimensional acoustic Doppler velocimeter. Three-dimensional velocity records, turbulent kinetic energy characteristics, and Reynolds stresses were analysed. The addition of vegetation on a sloping streambank increased the free stream streamwise velocity as compared to a bare streambank. Velocity in the downstream direction decreased in the area close to the streambank boundary for all vegetation treatments. Tree turbulence intensity and Reynolds stress distributions were similar to the bare condition due to the sparse tree placement characteristic of mature forests. The turbulence caused by the upright shrub treatment increased turbulent kinetic energy and Reynolds stresses near the streambank, particularly at the toe. The flexible grass vegetation folded and protected the streambank, reducing shear stress near the boundary. Copyright © 2009 John Wiley & Sons, Ltd. [source] A Modular Injection System, Multilevel Sampler, and Manifold for Tracer TestsGROUND WATER, Issue 6 2003Brian J. Mailloux Ground water injection and sampling systems were developed for bacterial transport experiments in both homogenous and heterogeneous unconsolidated, surficial aquifers. Two types of injection systems, a large single tank and a dynamic mixing tank, were designed to deliver more than 800 L of amended ground water to the aquifer over 12 hours, without altering the ground water temperature, pH, Eh, or dissolved gas composition. Two types of multilevel samplers (MLSs) were designed and installed. Permanent MLSs performed well for the homogenous surficial aquifer, but their installation procedure promoted vertical mixing, which could obfuscate experimental data obtained from vertically stratified, heterogeneous aquifers. A novel, removable MLS was designed to fit in 2- and 4-inch wells. Expandable O-rings between each sampling port hydraulically isolated each port for sample collection when a nut was tightened at the land surface. A low-cost vacuum manifold system designed to work with both MLS designs used 50 mL centrifuge tubes to efficiently sample 12 MLS ports with one peristaltic pump head. The integrated system was developed and used during four field campaigns over a period of three years. During each campaign, more than 3000 ground water samples were collected in less than one week. This system should prove particularly useful for ground water tracer, injection, and push-pull experiments that require high-frequency and/or high-density sampling. [source] Response Surface Designs for Experiments in BioprocessingBIOMETRICS, Issue 2 2006Steven G. Gilmour Summary Many processes in the biological industries are studied using response surface methodology. The use of biological materials, however, means that run-to-run variation is typically much greater than that in many experiments in mechanical or chemical engineering and so the designs used require greater replication. The data analysis which is performed may involve some variable selection, as well as fitting polynomial response surface models. This implies that designs should allow the parameters of the model to be estimated nearly orthogonally. A class of three-level response surface designs is introduced which allows all except the quadratic parameters to be estimated orthogonally, as well as having a number of other useful properties. These subset designs are obtained by using two-level factorial designs in subsets of the factors, with the other factors being held at their middle level. This allows their properties to be easily explored. Replacing some of the two-level designs with fractional replicates broadens the class of useful designs, especially with five or more factors, and sometimes incomplete subsets can be used. It is very simple to include a few two- and four-level factors in these designs by excluding subsets with these factors at the middle level. Subset designs can be easily modified to include factors with five or more levels by allowing a different pair of levels to be used in different subsets. 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