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Model Capable (model + capable)
Selected AbstractsOptimizing flow cytometric DNA ploidy and S-phase fraction as independent prognostic markers for node-negative breast cancer specimensCYTOMETRY, Issue 3 2001C.B. Bagwell Abstract Developing a reliable and quantitative assessment of the potential virulence of a malignancy has been a long-standing goal in clinical cytometry. DNA histogram analysis provides valuable information on the cycling activity of a tumor population through S-phase estimates; it also identifies nondiploid populations, a possible indicator of genetic instability and subsequent predisposition to metastasis. Because of conflicting studies in the literature, the clinical relevance of both of these potential prognostic markers has been questioned for the management of breast cancer patients. The purposes of this study are to present a set of 10 adjustments derived from a single large study that optimizes the prognostic strength of both DNA ploidy and S-phase and to test the validity of this approach on two other large multicenter studies. Ten adjustments to both DNA ploidy and S-phase were developed from a single node-negative breast cancer database from Baylor College (n = 961 cases). Seven of the adjustments were used to reclassify histograms into low-risk and high-risk ploidy patterns based on aneuploid fraction and DNA index optimum thresholds resulting in prognostic P values changing from little (P < 0.02) or no significance to P < 0.000005. Other databases from Sweden (n = 210 cases) and France (n = 220 cases) demonstrated similar improvement of DNA ploidy prognostic significance, P < 0.02 to P < 0.0009 and P < 0.12 to P < 0.002, respectively. Three other adjustments were applied to diploid and aneuploid S-phases. These adjustments eliminated a spurious correlation between DNA ploidy and S-phase and enabled them to combine independently into a powerful prognostic model capable of stratifying patients into low, intermediate, and high-risk groups (P < 0.000005). When the Baylor prognostic model was applied to the Sweden and French databases, similar significant patient stratifications were observed (P < 0.0003 and P < 0.00001, respectively). The successful transference of the Baylor prognostic model to other studies suggests that the proposed adjustments may play an important role in standardizing this test and provide valuable prognostic information to those involved in the management of breast cancer patients. Cytometry (Comm. Clin. Cytometry) 46:121,135, 2001. © 2001 Wiley-Liss, Inc. [source] An investigation of tuned liquid dampers equipped with damping screens under 2D excitationEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 7 2005M. J. Tait Abstract This paper reports on the results of a study conducted on tanks partially filled with water, representing tuned liquid dampers (TLD), subjected to both 1D and 2D horizontal excitations. The sloshing response of the water in the tank is characterized by the free surface motion, the resulting base shear force, and evaluation of the energy dissipated by the sloshing water. A 1D non-linear flow model capable of simulating a TLD equipped with damping screens is employed to model a 2D TLD. Application of this particular model requires the assumption that the response is decoupled and can be treated as the summation of two independent 1D TLDs. Results from the non-linear flow model are compared with the 2D experimental shake table test results leading to a validation of the decoupled response assumption. This attractive decoupled response property allows square and rectangular tanks to be used as 2D TLDs, which can simultaneously reduce the dynamic response of a structure in two perpendicular modes of vibration. Copyright © 2005 John Wiley & Sons, Ltd. [source] Deformation analysis of notched components and assessment of approximate methodsFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 11 2001Y. Jiang Finite element modelling was conducted on notched members subjected to proportional and non-proportional loading. A recently developed cyclic plasticity model capable of accurately describing cyclic material behaviour was implemented into a finite element code. A plate with a central hole and a shaft with a circumference groove were studied. Approximate methods for the notched problems were critically evaluated using the finite element results. [source] A Micro-Simulation Approach to Modelling Spatial Unemployment DisparitiesGROWTH AND CHANGE, Issue 3 2010DAVID PHILIP MCARTHUR ABSTRACT This paper aims to construct a comprehensive model capable of simulating spatial unemployment disparities. The key feature of the model is that it simultaneously deals with commuting and migration. Much of the existing literature simply models one adjustment mechanism at a time. This paper adopts a micro-simulation approach to build a model which can deal with equilibrium and disequilibrium unemployment disparities in a context where commuting and migration are possible. The model is then used to demonstrate the importance of considering both types of flows and to guide future empirical and theoretical work in the area. [source] Disentangling the effects of morbidity and life expectancy on labor market outcomesHEALTH ECONOMICS, Issue 6 2002M. Christopher Auld Abstract Using a unique longitudinal dataset tracking the experiences of patients diagnosed with HIV+ disease, this paper develops and estimates a model capable of recovering the effect of revisions in life expectancy on labor market outcomes. The data allow us to estimate the effect of changes in health status (as objectively measured by CD4 counts) and the impact of learning that one is HIV+, which we interpret as a negative shock to life expectancy. Both parametric and distribution-free models robustly indicate that decreases in health have little effect on labor demand but decrease probability of employment. We conclude that, in this sample, negative association between income and health is attributable mostly to the effect of altered incentives induced by changes in life expectancy. Copyright © 2002 John Wiley & Sons, Ltd. [source] Prediction of unsteady, separated boundary layer over a blunt body for laminar, turbulent, and transitional flowINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2004D. Scott Holloway Abstract The focus of this paper is to study the ability of unsteady RANS-based CFD to predict separation over a blunt body for a wide range of Reynolds numbers particularly the ability to capture laminar-to-turbulent transition. A perfect test case to demonstrate this point is the cylinder-in-crossflow for which a comparison between experimental results from the open literature and a series of unsteady simulations is made. Reynolds number based on cylinder diameter is varied from 104 to 107 (subcritical through supercritical flow). Two methods are used to account for the turbulence in the simulations: currently available eddy,viscosity models, including standard and realizable forms of the k,, model; and a newly developed eddy,viscosity model capable of resolving boundary layer transition, which is absolutely necessary for the type and range of flow under consideration. The new model does not require user input or ,empirical' fixes to force transition. For the first time in the open literature, three distinct flow regimes and the drag crisis due to the downstream shift of the separation point are predicted using an eddy,viscosity based model with transition effects. Discrepancies between experimental and computational results are discussed, and difficulties for CFD prediction are highlighted. Copyright © 2004 John Wiley & Sons, Ltd. [source] The Interface of Globalization and Peripheral Land in the Cities of the South: Implications for Urban Governance and Local Economic DevelopmentINTERNATIONAL JOURNAL OF URBAN AND REGIONAL RESEARCH, Issue 2 2007RAMIN KEIVANI Abstract This essay examines the impact of globalization on land peripheral to large cities of the south. It identifies such land as providing major arenas for contested claims between the requirements of international firms and those of local inhabitants and businesses, entailing both threats and opportunities in terms of local economic development. Much depends on the urban governance and institutional processes surrounding the use and allocation of land that are themselves directly influenced by the globalization process. In many cities national, state or provincial governments have set up special parastatal organizations with substantial funding and significant decision-making powers over infrastructure development and land use to facilitate the rebirth of their cities as havens for international investment. In the process local municipalities and the local population are often excluded from the decision-making process, while being left to cope with the aftermath and maintenance of the grand projects. The essay identifies weaknesses in elite governance models usually centred at the state or national levels, and asks if a better alternative may be a local government-led ,inclusive leadership' model capable of clear leadership, greater coordination of different governance layers and inclusion of local actors. Résumé Cet essai étudie l'impact de la mondialisation sur les terrains situés à la périphérie des grandes villes du Sud. Il identifie ces terrains comme des scènes majeures de contradiction entre les besoins des multinationales et les revendications des entreprises et habitants locaux, ce qui créent à la fois menaces et opportunités en termes d'expansion économique locale. Le résultat dépend largement des processus institutionnels et de gouvernance urbaine qui entourent l'utilisation et l'affectation des terrains, processus eux-mêmes directement influencés par la mondialisation. Dans de nombreuses villes, les organes de gouvernement nationaux, étatiques ou provinciaux ont créé des entités para-étatiques spécialisées, dotées de fonds et de pouvoirs décisionnels considérables en matière d'aménagement des infrastructures et d'occupation des sols, afin de réinstaurer leur ville en terre d'accueil de l'investissement international. Or, les municipalités et populations locales sont souvent exclues du processus de décision alors qu'on les laisse assumer les conséquences et la maintenance des grands projets. L'article repère les faiblesses des modèles de gouvernance par les élites, généralement centrés aux niveaux de l'Etat ou de la nation, et se demande si un modèle de ,leadership inclusif' sous la houlette du gouvernement ne serait pas une meilleure alternative, permettant un leadership clair, une meilleure coordination des différentes strates de gouvernance et l'intégration des acteurs locaux. [source] A critical evaluation of current views regarding eye movement desensitization and reprocessing (EMDR): Clarifying points of confusionJOURNAL OF CLINICAL PSYCHOLOGY, Issue 1 2002Byron R. Perkins EMDR is an active psychological treatment for PTSD that has received widely divergent reactions from the scientific and professional community. This article examines points of confusion in the published literature on EMDR, including the theoretical, empirical, and historical issues around EMDR and placebo effects, exposure procedures, the eye movement component, treatment fidelity issues, and outcome studies. It also examines historical information relevant to the scientific process and charges of "pseudoscience" regarding EMDR. We conclude that the confusion in the literature is due to (a) the lack of an empirically validated model capable of convincingly explaining the effects of the EMDR method, (b) inaccurate and selective reporting of research, (c) some poorly designed empirical studies, (d) inadequate treatment fidelity in some outcome research, and (e) multiple biased or inaccurate reviews by a relatively small group of authors. Reading the original research articles frequently helps to reduce the confusion arising from the research review literature. © 2002 John Wiley & Sons, Inc. J Clin Psychol 58: 77,97, 2002. [source] The effect of cell size distribution during the cooling stage of cryopreservation without CPAAICHE JOURNAL, Issue 8 2010S. Fadda Abstract A novel model capable of quantitatively describing and predicting intracellular ice formation (IIF) as a function of temperature in a cell population characterized by a size distribution is proposed. The model overcomes the classical approach which takes into account a population of identically sized cells. The size distribution dynamics of a cell population in response to water osmosis and IIF occurrence during the cooling stage of a standard cryopreservation protocol without using cryoprotective agent (CPA) is simulated by means of a suitable population balance approach. Specifically, the model couples the classical water transport equation developed by Mazur1 to the quantitative description of nucleation and diffusion-limited growth of ice crystals in the framework of a 1-D population balance equation (PBE). It is found that IIF temperature depends on the cell size, i.e., it is higher for larger cells. Correspondingly, the probability of IIF (PIIF) results to be dependent on the initial size distribution of the cell population. Model's parameters related to the osmotic behavior of the cell population and to IIF kinetics are obtained by comparison between theoretical results and suitable experimental data of isolated rat hepatocytes available in the literature. Model reliability is successfully verified by predicting the experimental data of PIIF at different, constant cooling rates with better accuracy as compared to the theoretical approaches available in the literature. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Prostate cancer detection with multi-parametric MRI: Logistic regression analysis of quantitative T2, diffusion-weighted imaging, and dynamic contrast-enhanced MRIJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2009Deanna L. Langer MSc Abstract Purpose To develop a multi-parametric model suitable for prospectively identifying prostate cancer in peripheral zone (PZ) using magnetic resonance imaging (MRI). Materials and Methods Twenty-five radical prostatectomy patients (median age, 63 years; range, 44,72 years) had T2-weighted, diffusion-weighted imaging (DWI), T2-mapping, and dynamic contrast-enhanced (DCE) MRI at 1.5 Tesla (T) with endorectal coil to yield parameters apparent diffusion coefficient (ADC), T2, volume transfer constant (Ktrans) and extravascular extracellular volume fraction (ve). Whole-mount histology was generated from surgical specimens and PZ tumors delineated. Thirty-eight tumor outlines, one per tumor, and pathologically normal PZ regions were transferred to MR images. Receiver operating characteristic (ROC) curves were generated using all identified normal and tumor voxels. Step-wise logistic-regression modeling was performed, testing changes in deviance for significance. Areas under the ROC curves (Az) were used to evaluate and compare performance. Results The best-performing single-parameter was ADC (mean Az [95% confidence interval]: Az,ADC: 0.689 [0.675, 0.702]; Az,T2: 0.673 [0.659, 0.687]; Az,Ktrans: 0.592 [0.578, 0.606]; Az,ve: 0.543 [0.528, 0.557]). The optimal multi-parametric model, LR-3p, consisted of combining ADC, T2 and Ktrans. Mean Az,LR-3p was 0.706 [0.692, 0.719], which was significantly higher than Az,T2, Az,Ktrans, and Az,ve (P < 0.002). Az,LR-3p tended to be greater than Az,ADC, however, this result was not statistically significant (P = 0.090). Conclusion Using logistic regression, an objective model capable of mapping PZ tumor with reasonable performance can be constructed. J. Magn. Reson. Imaging 2009;30:327,334. © 2009 Wiley-Liss, Inc. [source] A C1 microkinetic model for methane conversion to syngas on Rh/Al2O3AICHE JOURNAL, Issue 4 2009Matteo Maestri Abstract A microkinetic model capable of describing multiple processes related to the conversion of natural gas to syngas and hydrogen on Rh is derived. The parameters of microkinetic models are subject to (intrinsic) uncertainty arising from estimation. It is shown that intrinsic uncertainty could markedly affect even qualitative model predictions (e.g., the rate-determining step). In order to render kinetic models predictive, we propose a hierarchical, data-driven methodology, where microkinetic model analysis is combined with a comprehensive, kinetically relevant set of nearly isothermal experimental data. The new, thermodynamically consistent model is capable of predicting several processes, including methane steam and dry reforming, catalytic partial oxidation, H2 and CO rich combustion, water-gas shift and its reverse at different temperatures, space velocities, compositions and reactant dilutions, using the measured Rh dispersion as an input. Comparison with other microkinetic models is undertaken. Finally, an uncertainty analysis assesses the effect of intrinsic uncertainty and catalyst heterogeneity on the overall model predictions. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Detailed modeling of stationary and transient mass transfer across pervaporation membranesAICHE JOURNAL, Issue 6 2001Jürgen Bausa The slow dynamic behavior of mass transfer in pervaporation has been reported by different authors. Until now, however, only a little experimental data and no model capable to describe this phenomenon have been available. A new detailed model for mass transfer in pervaporation, based on the dual-sorption theory, Maxwell-Stefan diffusion, and the UNIQUAC model, is proposed. This model is capable of properly describing mass transfer at steady state and during transients. Model parameters for two different PVA/PAN membranes for ethanol/water separation are given. The model shows good agreement with both steady state and dynamic experimental data. [source] Particulate Matter in the Ross Sea: a Spreading ModelMARINE ECOLOGY, Issue 2002Sergio Tucci Abstract. Within the framework of the C.L.I.M.A. Project, a part of the Italian Research Program in Antarctica, the Total Particulate Matter (TPM) was used as a natural marker to characterise the water masses. The dynamics of TPM was estimated by using a numerical model capable of following the evolution of the basin during the ice absence in summer. The first numerical simulation, with horizontally constant initial conditions and the absence of TPM source areas, merely reveals how TPM passive dispersion is strongly influenced by the Ross Ice Shelf and bathymetry. The second simulation, with TPM concentration horizontally variable and vertically decreasing layers, shows a dynamic evolution of TPM that is in agreement with experimental data. On the surface, in correspondence with the shelf-break, an out-flowing flux with particulate matter contribution coming from Ross Ice Shelf is recognised. The TPM concentration may be linked to the ice melting due to the Antarctic Surface Water, with production of Shallow Ice Shelf Water. The numerical model produces, near the Drygalski area, two cells with high concentration. This numerical evolution is confirmed by the 1990 data (Spezie et al, 1993) that clearly show these two areas and their correlations with the Drygalski contributions (the inner area) and with the thermo-haline front (the external one). This condition is evident in the 1994-1995 data too (Bu-dillon et al, 1999). In this case the authors observed that the Circumpolar Deep Water penetrates onto the shelf at about 174°E; then, modifying its properties, it follows a southward path for about 200 km. The Antarctic Shelf Front (ASF) separates CDW from the colder shelf water with a high concentration of suspended matter. At the 300-meter level, the diffusion of the particulate matter directed under the RIS, towards the continental shelf, seems to be an important feature. Very high TPM values are also present in the deep water in the area off the Drygalski Glacier; this evolution agrees with the ,400 m data collected during the 1990,1991 cruise (Spezie et al., 1993). [source] Optical bandgap and quantum well model in hydrogenated amorphous silicon carbon alloy filmsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003D.K. BasaArticle first published online: 14 JAN 200 Abstract Hydrogenated amorphous silicon carbon alloy (a-SiC : H) films of various composition were prepared by the rf glow discharge decomposition of acetylene and silane as well as ethylene and silane and were also annealed for various annealing temperatures. Careful and detailed IR absorption and the optical bandgap (Eopt) measurements were undertaken for a-SiC : H films of different composition (x) and annealing temperatures (Ta). Interesting variation of Eopt with x and Ta have been observed. Our study demonstrates, for the first time, that the models involving alloying or/and ordering break down and the proposed quantum well model based on heterogeneity is found to be the only model capable of explaining the observed variation of Eopt. This, consequently, may have considerable implications. [source] Computational Simulation of the Blood Separation ProcessARTIFICIAL ORGANS, Issue 8 2005Sandro De Gruttola Abstract:, The aim of this work is to construct a computational fluid dynamics model capable of simulating the quasitransient process of apheresis. To this end a Lagrangian,Eulerian model has been developed which tracks the blood particles within a delineated two-dimensional flow domain. Within the Eulerian method, the fluid flow conservation equations within the separator are solved. Taking the calculated values of the flow field and using a Lagrangian method, the displacement of the blood particles is calculated. Thus, the local blood density within the separator at a given time step is known. Subsequently, the flow field in the separator is recalculated. This process continues until a quasisteady behavior is reached. The simulations show good agreement with experimental results. They shows a complete separation of plasma and red blood cells, as well as nearly complete separation of red blood cells and platelets. The white blood cells build clusters in the low concentrate cell bed. [source] Theoretical analysis of excipient concentrations during the final ultrafiltration/diafiltration step of therapeutic antibodyBIOTECHNOLOGY PROGRESS, Issue 4 2009Fudu Miao Abstract Diafiltration of a protein solution into a new buffer is a common final step in biopharmaceutical manufacturing. However, the excipient concentrations in the retentate are not always equal to their corresponding concentrations in the new buffer (diafiltration buffer). This phenomenon was observed repeatedly during diafiltration of different therapeutic monoclonal antibodies in which the concentrations of histidine and either sorbitol or sucrose (depending on which was chosen for the diafiltration buffer) in the retentate were lower than in the diafiltration buffer. Experimental studies and theoretical analyses of the ultrafiltration/diafiltration (UF/DF) step were carried out to determine the primary causes of the phenomenon and to develop a mathematical model capable of predicting retentate excipient concentrations. The analyses showed that retentate histidine concentration was low primarily because of repulsive charge interactions between positively-charged histidine molecules and positively-charged protein molecules, and that volume exclusion effects were secondary for like-charged molecules. The positively-charged protein molecules generate an electrical potential that cause an uneven distribution of charged histidine molecules. This interaction was used to construct a mathematical model based on the Poisson-Boltzmann equation. The model successfully predicted the final histidine concentration in the diafiltered product (retentate) from the UF/DF development and production runs, with good agreement across a wide range of protein and histidine concentrations for four therapeutic monoclonal antibodies. The concentrations of uncharged excipients (sorbitol or sucrose) were also successfully predicted using previously established models, with volume exclusion identified as the primary cause of differences in uncharged excipient concentrations in the retentate and diafiltration buffer. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Regioselective Enzymatic Diol Esterification in Batch and Fixed-Bed Adsorptive Reactors: Experiments and ModelingBIOTECHNOLOGY PROGRESS, Issue 4 2000Cristiano Migliorini The dynamic behavior of batch and fixed-bed adsorptive reactors is studied for the enzyme-catalyzed regioselective esterification of propionic acid and 2-ethyl-1,3-hexanediol in hexane. The reaction is equilibrium-limited with an apparent equilibrium constant of 0.6 ± 0.1 at 22 °C. Moreover, accumulation of water produced in the reaction onto the biocatalyst causes a decrease in the catalytic activity. As a result, improvements in both reaction rate and final conversion can be achieved by operating in an adsorptive-reactor mode. Control of water in the reactor is achieved with a catalytically inert ion-exchange resin in Na-form. The resin prevents an excessive accumulation of water on the biocatalyst and reduces equilibrium limitations. The thermodynamic activity of water is identified as a key parameter for the design of such reactors. A mathematical model capable of predicting the water activity as a function of the varying concentrations of reactants and products is thus developed and found to successfully predict the experimental behavior observed in laboratory reactors. Substantial improvements in performance predicted by the model are seen experimentally in batch reactions and during the transient operation of continuous-flow fixed-bed reactors combining adsorptive and catalytic functions. [source] The need and total cost of Finnish eyecare services: a simulation model for 2005,2040ACTA OPHTHALMOLOGICA, Issue 8 2009Anja Tuulonen Abstract. Purpose:, The aims of this study were: (i) to create a structural simulation model capable of predicting the future need and cost of eyecare services in Finland; and (ii) to test and rank different policy alternatives for access to care and the required physician workforce. Methods:, Using the system dynamics approach, the number and cost of patients with cataract, glaucoma, diabetic retinopathy and age-related macular degeneration (AMD) were described with causal-loop diagrams and were then translated into a set of mathematical equations to build a computer simulation model. Mathematically, the problem was formulated as a set of differential equations that were solved numerically with specialized software. The validity of the model was tested against prevalence and administrative historical data. The costs covered by the public sector in Finland were obtained from 2003 from the Finnish Hospital Discharge Register (including outpatient care), the Finnish Social Insurance Institution and a survey of hospital price lists. Different levels of access to public care were then simulated in four eye diseases, for which the model estimated the need for services and resources and their costs in the years 2005,2040. Results:, The model forecasted that the adoption of the 2005 national ,access to care' criteria for cataract surgery would shorten waiting lists. If the workload of Finnish ophthalmologists were kept at the 2003 level, the graduation rate of new ophthalmologists would have to increase by 75% from the current level. If all glaucoma patients were followed in the public sector in future, even this increase in training would not meet the demand for physician workforce. The current model indicated that the screening frequency of diabetes can be increased without large sacrifices in terms of costs. AMD therapy has a significant role in the allocation of future resources in eyecare. The modelling study predicted that ageing alone will increase the costs of eyecare during the next four decades in Finland by about 1% per year in real terms (undiscounted and without inflation of unit costs). The increases in total yearly costs were on average 8.6% between 2001 and 2003. Conclusions:, The results of this modelling study indicate that policy initiatives, such as defining criteria for access to care, can have substantial implications on the demand for care and waiting times whereas the effect of ageing alone was relatively small. Measures to control several other factors , such as the adoption and price level of new technologies, treatments and practice patterns , will be at least equally important in order to restrain healthcare costs effectively. [source] | |||||||||||||||||||