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Appropriate Models (appropriate + models)
Selected AbstractsExperimental modelling and intelligent control of a wood-drying kilnINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 8 2001Givon Chuen Kee Yan Abstract Proper control of the wood-drying kiln is crucial in ensuring satisfactory quality of dried wood and in minimizing drying time. This paper presents the development, implementation, and evaluation of a control system for a lumber drying kiln process incorporating sensory feedback from in-wood moisture content sensors and intelligent control such that the moisture content of lumber will reach and stabilize at the desired set point without operator interference. The drying process is difficult to model and control due to complex dynamic nonlinearities, coupling effects among key variables, and process disturbances caused by the variation of lumber sizes, species, and environmental factors. Through system identification scheme using experimental data and recursive least-squares algorithm for parameter estimation, appropriate models are developed for simulation purpose and controller design. Two different control methodologies are employed and compared: a conventional proportional-integral-derivative (PID) controller and a direct fuzzy logic controller (FLC), and system performance is evaluated through simulations. The developed control system is then implemented in a downscaled industrial kiln located at the Innovation Centre of National Research Council (NRC) of Canada. This experimental set-up is equipped with a variety of sensors, including thermocouples for temperature feedback, an air velocity transmitter for measuring airflow speed in the plenum, relative humidity sensors for measuring the relative humidity inside the kiln, and in-wood moisture content sensors for measuring the moisture content of the wood pieces. For comparison, extensive experimental studies are carried out on-line using the two controllers, and the results are evaluated to tune the controller parameters to achieve good performance in the wood-drying kiln. The combination of conventional control with the intelligent control promises improved performance. The control system developed in this study may be applied in industrial wood-drying kilns, with a clear potential for improved quality and increased speed of drying. Copyright © 2001 John Wiley & Sons, Ltd. [source] Creative marketing and the art organisation: what can the artist offer?INTERNATIONAL JOURNAL OF NONPROFIT & VOLUNTARY SECTOR MARKETING, Issue 2 2002Ian Fillis The poem ,My Paintings', written in a deliberate, uncorrected dyslexic style offers an insight into the mind of a present day avant garde bad boy of British art, Billy Childish. Constantly challenging the art establishment through public demonstrations of distaste against the annual Turner Prize,[Button, V. (1999) ,The Turner Prize', Tate Gallery Publishing, London.] Childish and his cohorts launched an alternative, Stuck-ist, art manifesto,[Alberge, D. (1999) ,Rebels Get Stuck into the Brit Artists', The Times, Thursday 26th August, p. 7.] in the belief that it would assist in a shift in public perception of what good art is, as well as influence the creative practice of those artists concerned with more traditional, authentic forms of art. Childish's ex-girlfriend Tracey Emin, however, has had other ideas. She has revelled in mass media exposure and now dismisses the concept of traditional painting as a valid art from.[Brown, N. (1998) ,Tracey Emin', Art Data, UK.] These are two examples of contrasting creative, artistic behaviour. Their creativity has resulted in varying levels of commercial success. By examining the role that creativity plays in determining how the idea for a creative product is first identified, through to its commercial exploitation, there are valuable lessons contained in such a process for both profit-oriented and nonprofit art organisations alike. Instead of constantly fighting the conflicting philosophies of art for art's sake versus art for business sake, following the market and consumer demand, there is a much more effective method for establishing longer-term success, which mirrors the creative practice of the artist. The existing literature on arts marketing is examined. A critique of the usefulness of current thinking is presented, with the recommendation that the formal models of marketing offered in arts marketing literatures can only ever hope to offer general advice on marketing. What is called for is a much more in-depth analysis of how creative entrepreneurial marketers as artists can offer alternative visualisations of more appropriate models of marketing for the industry. This in turn should result in the stimulation of creative research methodologies that can inform both theory and practice within arts marketing in particular, and the wider remit of marketing in general. The use of the metaphor and the examination of published biographies of creative individuals are used to construct a manifesto of marketing artistry. Copyright © 2002 Henry Stewart Publications [source] Fibrous Dysplasia as a Stem Cell Disease,JOURNAL OF BONE AND MINERAL RESEARCH, Issue S2 2006Mara Riminucci Abstract At a time when significant attention is devoted worldwide to stem cells as a potential tool for curing incurable diseases, fibrous dysplasia of bone (FD) provides a paradigm for stem cell diseases. Consideration of the time and mechanism of the causative mutations and of nature of the pluripotent cells that mutate in early embryonic development indicates that, as a disease of the entire organism, FD can be seen as a disease of pluripotent embryonic cells. As a disease of bone as an organ, in turn, FD can be seen as a disease of postnatal skeletal stem cells, which give rise to dysfunctional osteoblasts. Recognizing FD as a stem cell disease provides a novel conceptual angle and a way to generate appropriate models of the disease, which will continue to provide further insight into its natural history and pathogenesis. In addition, skeletal stem cells may represent a tool for innovative treatments. These can be conceived as directed to alter the in vivo behavior of mutated stem cells, to replace mutated cells through local transplantation, or to correct the genetic defect in the stem cells themselves. In vitro and in vivo models are currently being generated that will permit exploration of these avenues in depth. [source] Biomechanical evaluation of healing in a non-critical defect in a large animal model of osteoporosisJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2003C. A. Lill Abstract Current methods for fracture treatment in osteoporosis are not always sufficient. To develop new fixation strategies (both mechanical and biological) requires pre-clinical testing utilizing appropriate models. The aim of this study was to apply a recently developed sheep model of osteoporosis to the study of healing in a non-critical long bone defect. A standardized transverse mid-shaft tibial osteotomy (with a fracture gap of 3 mm) was performed in seven osteoporotic and seven normal sheep and stabilized with a special external fixator for 8 weeks. The fixator was used for weekly in vivo bending stiffness measurements. Ex vivo bending stiffness and torsional stiffness of the callus zone were also determined. Callus area, callus density, and osteoporosis status were determined at 0, 4, and 8 weeks using peripheral quantitative computed tomography. The increase of in vivo bending stiffness of the callus was delayed approximately 2 weeks in osteoporotic animals. A significant difference (33%) in torsional stiffness was found between the osteotomized and contralateral intact tibia in osteoporotic animals, but no significant difference occurred in normal sheep (2%). In osteoporotic animals, ex vivo bending stiffness was reduced 21% (p = 0.05). Bending stiffness was correlated with callus density (r = 0.76, r = 0.53); torsional stiffness was correlated with callus area (r = 0.60) and to a lesser extent with callus density (r = 0.53). This study demonstrated a delay of fracture healing in osteoporotic sheep tibiae with respect to callus formation, mineralization, and mechanical properties. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Effect of cyclic mechanical loading on osteoclast recruitment in periodontal tissueJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2010K. Nozaki Nozaki K, Kaku M, Yamashita Y, Yamauchi M, Miura H. Effect of cyclic mechanical loading on osteoclast recruitment in periodontal tissue. J Periodont Res 2009; doi: 10.1111/j.1600-0765.2008.01193.x. © 2009 The Authors. Journal compilation © 2009 Blackwell Munksgaard Background and Objective:, It is well accepted that cyclic mechanical loading induces osteoclastogenesis in periodontal tissue, but its molecular mechanisms are not well understood, in part because of a lack of appropriate models. In this study, we investigated a novel device that allows cyclic mechanical loading to be performed in a well-controlled manner. Furthermore, by employing this model, the effect of cyclic loading on osteoclast recruitment in the periodontal tissue was described. Material and Methods:, By using a newly developed device, the cyclic loading of 20 n (reference loading corresponding to the fracture hardness of dietary pellets) and two excessive loadings (i.e. 30 and 40 n) were applied to maxillary right molars in rats for up to 7 d, and osteoclast recruitment in the periodontal tissue was evaluated by analyzing relevant marker proteins using immunohistochemistry. Results:, Osteoclastogenesis was induced by day 3 within alveolar bone subjected to a compression force of 30 n. With both 30 and 40 n loadings, cells that were positive to for tartrate-resistant acid phosphate, receptor activator of nuclear factor-,B ligand and osteoprotegerin were significantly increased in the alveolar bone/periodontal ligament in a time-dependent manner. Conclusion:, A new device was developed that allows various levels of cyclic mechanical loading to be exerted. By using this device in rats, early events of osteoclast recruitment in the periodontal tissues were observed with excessive loadings in a time-dependent manner, indicating the usefulness of this model. [source] GROUPWISE MODELING STUDY OF BACTERIALLY IMPAIRED WATERSHEDS IN TEXAS: CLUSTERING ANALYSIS,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 4 2006Sabu Paul ABSTRACT: Under the Clean Water Act (CWA) program, the Texas Commission on Environmental Quality (TCEQ) listed 110 stream segments in the year 2000 with pathogenic bacteria impairment. A study was conducted to evaluate the probable sources of pollution and characterize the watersheds associated with these impaired water bodies. The primary aim of the study was to group the water bodies into clusters having similar watershed characteristics and to examine the possibility of studying them as a group by choosing models for total maximum daily load (TMDL) development based on their characteristics. This approach will help to identify possible sources and determine appropriate models and hence reduce the number of required TMDL studies. This in turn will help in reducing the effort required to restore the health of the impaired water bodies in Texas. The main characteristics considered for the classification of water bodies were land use distribution within the watershed, density of stream network, average distance of land of a particular use to the closest stream, household population, density of on-site sewage facilities (OSSFs), bacterial loading from different types of farm animals and wildlife, and average climatic conditions. The climatic data and observed instream fecal coliform bacteria concentrations were analyzed to evaluate seasonal variability of instream water quality. The grouping of water bodies was carried out using the multivariate statistical techniques of factor analysis/principal component analysis, cluster analysis, and discriminant analysis. The multivariate statistical analysis resulted in six clusters of water bodies. The main factors that differentiated the clusters were found to be bacterial contribution from farm animals and wildlife, density of OSSFs, density of households connected to public sewers, and land use distribution. [source] Use of primates in research: A global overviewAMERICAN JOURNAL OF PRIMATOLOGY, Issue 4 2004Hans-Erik Carlsson Abstract We assessed the use of nonhuman primates and nonhuman primate biological material in research by reviewing studies published in 2001 in peer-reviewed journals. The number and species of primates used, the origin of the animals, the type of study, the area of research of the investigation, and the location at which the research was performed were tabulated. Additionally, factors related to the animals that may have affected the outcome of the experiments were recorded. A total of 2,937 articles involving 4,411 studies that employed nonhuman primates or nonhuman primate biological material were identified and analyzed. More than 41,000 animals were represented in the studies published in 2001. In the 14% of studies for which re-use could be determined, 69% involved animals that had been used in previous experiments. Published studies most commonly used nonhuman primates or nonhuman primate biological material from the species Chlorocebus aethiops (19%), Macaca mulatta (18%), M. fascicularis (9%), and Papio spp. (6%). Of these studies, 54% were classified as in vitro studies, 14% as noninvasive, 30% as chronic, and 1% were considered acute. Nonhuman primates were primarily used in research areas in which they appear to be the most appropriate models for humans. The most common areas of research were microbiology (including HIV/AIDS (26%)), neuroscience (19%), and biochemistry/chemistry (12%). Most (84%) of the primate research published in 2001 was conducted in North America, Europe, and Japan. The animals and conditions under which they were housed and used were rarely described. Although it is estimated that nonhuman primates account for an extremely small fraction of all animals used in research, their special status makes it important to report the many husbandry and environmental factors that influence the research results generated. This analysis has identified that editors rarely require authors to provide comprehensive information concerning the subjects (e.g., their origin), treatment conditions, and experimental procedures utilized in the studies they publish. The present analysis addresses the use of primates for research, including the effects of a shortage of suitable nonhuman primate subjects in many research areas. Am. J. Primatol. 63:225,237, 2004. © 2004 Wiley-Liss, Inc. [source] The response of tree squirrels to fragmentation: a review and synthesisANIMAL CONSERVATION, Issue 4 2005John L. Koprowski Habitat fragmentation is often considered a major threat to biodiversity; however, our understanding of how fragmentation impacts populations is poor. Identifying appropriate models for such studies is difficult. Tree squirrels are dependent on mature forests for food, cover and nests; these are habitats that are being fragmented rapidly and that are easily defined by humans. Squirrels represent excellent models for study of fragmentation. The literature on tree squirrels was reviewed to glean data on density and home-range size in forest fragments. Sufficient data were available on four species (Sciurus carolinensis, S. niger, S. vulgaris, Tamiasciurus hudsonicus). Density was negatively related to fragment size for S. carolinensis and S. niger and marginally so for T. hudsonicus. Sciurus vulgaris did not exhibit this relationship. Home-range size was analysed for three species of Sciurus and was positively related to forest fragment size for S. carolinensis and S. niger. Again, only S. vulgaris did not to show this relationship. Sciurus vulgaris is rarely found in small forest fragments and is believed to be especially sensitive to fragmentation; other tree squirrels appear to be sensitive to fragmentation in more subtle ways. Home range compaction provides a mechanism by which densities may increase in small fragments. The demographic consequences resultant from the high densities of squirrels found in small woodlots are not known but may explain the forest damage, avian nest predation and reduced diversity often cited to occur in woodland fragments. [source] Delivering culturally appropriate residential rehabilitation for urban Indigenous Australians: a review of the challenges and opportunitiesAUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 2010Kate Taylor Abstract Objective: To review the challenges facing Indigenous and mainstream services in delivering residential rehabilitation services to Indigenous Australians, and explore opportunities to enhance outcomes. Methods: A literature review was conducted using keyword searches of databases, on-line journals, articles, national papers, conference proceedings and reports from different organisations, with snowball follow-up of relevant citations. Each article was assessed for quality using recognised criteria. Results: Despite debate about the effectiveness of mainstream residential alcohol rehabilitation treatment, most Indigenous Australians with harmful alcohol consumption who seek help have a strong preference for residential treatment. While there is a significant gap in the cultural appropriateness of mainstream services for Indigenous clients, Indigenous-controlled residential organisations also face issues in service delivery. Limitations and inherent difficulties in rigorous evaluation processes further plague both areas of service provision. Conclusion: With inadequate evidence surrounding what constitutes ,best practice' for Indigenous clients in residential settings, more research is needed to investigate, evaluate and contribute to the further development of culturally appropriate models of best practice. In urban settings, a key area for innovation involves improving the capacity and quality of service delivery through effective inter-agency partnerships between Indigenous and mainstream service providers. [source] Training doctors in general practices: A review of the literatureAUSTRALIAN JOURNAL OF RURAL HEALTH, Issue 5 2006Karen Larsen Abstract Objective:,This study was undertaken to assess the evidence of whether new forms of medical training, where substantial training takes place in general practice, will be acceptable to GPs. In particular, we asked the questions: Are GPs willing to act as trainers and supervisors in their practices? Do GPs have the appropriate skills to be trainers? Do practices have the infrastructure and resources to support placements? And, are patients happy to be seen by medical students and General Practice Registrars? Design:,Key Australian and international databases, key Australian journals and key Australian websites were searched for literature on general practice-based training of medical students and General Practice Registrars. Results:,In the international and Australian literature, we found that many GPs consider training medical students and General Practice Registrars to be intrinsically satisfying. They vary in their skills, and most medical schools have made significant investments in training and support activities. Many practices do not have the necessary infrastructure, and investments need to be made if extended placements are to be successful. Many patients are happy to be seen by students and Registrars, but careful thought needs to be given to implementing appropriate models so that students have good learning opportunities, patients are not disadvantaged and general practices can operate efficiently. Conclusion:,The success of this new model of clinical placements is dependent on medical schools having a detailed understanding of the needs and expectations of GPs. [source] Human radiolabeled mass balance studies: objectives, utilities and limitationsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 4 2009Natalia Penner Abstract The determination of metabolic pathways of a drug candidate through the identification of circulating and excreted metabolites is vitally important to understanding its physical and biological effects. Knowledge of metabolite profiles of a drug candidate in animals and humans is essential to ensure that animal species used in toxicological evaluations of new drug candidates are appropriate models of humans. The recent FDA final guidance recommends that human oxidative metabolites whose exposure exceeds 10% of the parent AUC at steady-state should be assessed in at least one of the preclinical animal species used in toxicological assessment. Additional toxicological testing on metabolites that have higher exposure in humans than in preclinical species may be required. The metabolite profiles in laboratory animals and humans are generally accomplished by mass balance and excretion studies in which radiolabeled drugs are administered to these species. The biological fluids are collected, analysed for total radioactivity and evaluated for a quantitative profile of metabolites. Thus, these studies not only determine the rates and routes of excretion but also provide very critical information on the metabolic pathways of drugs in preclinical species and humans. In addition, these studies are required by regulatory agencies for the new drug approval process. Despite the usefulness of these radiolabeled mass balance studies, there is little concrete guidance on how to perform or assess these complex studies. This article examines the objectives, utilities and limitations of these studies and how these studies could be used for the determination of the metabolite exposure in animals and humans. Copyright © 2009 John Wiley & Sons, Ltd. [source] The utility of mixed-effects covariate analysis in rapid selection of doses in pediatric subjects: A case study with fexofenadine hydrochlorideBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 9 2004Rajesh Krishna Abstract Fexofenadine hydrochloride is a non-sedating antihistamine that is used in the treatment of symptoms associated with seasonal allergic rhinitis and chronic idiopathic urticaria. A pooled analysis of pharmacokinetic data from children 6 months to 12 years of age and adults was conducted to identify the dose(s) in children that produce exposures comparable to those in adults for the treatment of seasonal allergic rhinitis. The pharmacokinetic parameter database included peak and overall exposure data from 269 treatment exposures from 136 adult subjects, and 90 treatment exposures from 77 pediatric allergic rhinitis patients. The data were pooled and analysed using NONMEM software, version 5.0. A covariate model based on body weight and age and a power function model based on body weight were identified as appropriate models to describe the variability in fexofenadine oral clearance and peak concentration, respectively. Individual oral clearance estimates were on average 44%, 36% and 61% lower in children 6 to 12 years (n = 14), 2 to 5 years (n = 21), and 6 months to 2 years (n = 42), respectively, compared with adults. Trial simulations (n = 100) were carried out based on the final pharmacostatistical models and parameter estimates to identify the appropriate dose(s) in children relative to the marketed dose of 60 mg fexofenadine hydrochloride in adults. The trials were designed as crossover studies in 18 subjects comprising various potential dosing regimens with and without weight stratification. Pharmacokinetic parameter variability was assumed to have a log-normal distribution. Individual weights and ages were simulated using mean (SD) estimates derived from the studies used in this analysis and proportional measurement/model mis-specification errors derived from the analysis were incorporated into the simulation. The results indicated that a 30 mg dose of fexofenadine hydrochloride administered to children 1 to 12 years of age and weighing >10.5 kg and a 15 mg dose administered to children 6 months and older and weighing ,10.5 kg produces exposures similar to those seen with the 60 mg dose in adults. Copyright © 2004 John Wiley & Sons, Ltd. [source] Development and calibration of a nitrification PDE model based on experimental data issued from biofilter treating drinking waterBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2006I. Queinnec Abstract To remove ammonia for production of drinking water, nitrification can be performed in a bio-filter. At least 1 month is necessary to capture from the groundwater and then grow a sufficient amount of nitrifying bacteria to reach the desired removal efficiency. Improving start-up of bio-filters at low substrate concentration is therefore a major challenge. In this connection, it is important to develop appropriate models for designing, monitoring or analysing biofilm systems during start-up or following disinfection events. This study discusses the development and calibration of a nitrification PDE model which reflects the compromise between the complexity associated with the description of the full physical and biochemical mechanisms and the search for a simplified model with identifiable parameters. This model takes only the relevant phenomena (considering the full operating range) into account. The validity of the calibrated model has been evaluated through experiments under very different operational conditions, at the laboratory and under real industrial conditions, involving the full upstream chain of water treatment (iron oxidation and sand filter). © 2006 Wiley Periodicals, Inc. [source] Where should people with dementia live?BRITISH JOURNAL OF LEARNING DISABILITIES, Issue 1 2008Using the views of service users to inform models of care Accessible summary We wanted to know what people with learning disabilities know about dementia. We asked service users what the word meant to them, if they knew anyone with dementia, and what it was like to share a house with someone who has dementia. We learnt that: ,Service users can know a lot about dementia. ,Living with someone with dementia can be really hard , and staff do not always, have enough time for everyone else. ,Services should think more about how dementia affects everyone , not just the person who has the dementia. Summary This paper reports on research that illuminates how people with a learning disability understand dementia and indicates the implications of these understandings for developing appropriate models of care. As this new policy and practice area struggles to provide appropriate and effective models of care for people with a learning disability and dementia, an awareness of service users' understandings of dementia leads to a number of important insights. The wider research programme from which this paper is drawn aims to identify best practice in supporting people with learning disabilities to stay in their own homes as they grow older and develop dementia. A combination of focus groups, ethnography and individual interviews were conducted at eight sites across England. Participants were people with a learning disability who had dementia, and those who have lived with someone with dementia. The findings have the potential to improve support to this population as they grow older. 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