WorldWideScience

Sample records for modeling study combining

  1. Combining estimates of interest in prognostic modelling studies after multiple imputation: current practice and guidelines

    Directory of Open Access Journals (Sweden)

    Holder Roger L

    2009-07-01

    Full Text Available Abstract Background Multiple imputation (MI provides an effective approach to handle missing covariate data within prognostic modelling studies, as it can properly account for the missing data uncertainty. The multiply imputed datasets are each analysed using standard prognostic modelling techniques to obtain the estimates of interest. The estimates from each imputed dataset are then combined into one overall estimate and variance, incorporating both the within and between imputation variability. Rubin's rules for combining these multiply imputed estimates are based on asymptotic theory. The resulting combined estimates may be more accurate if the posterior distribution of the population parameter of interest is better approximated by the normal distribution. However, the normality assumption may not be appropriate for all the parameters of interest when analysing prognostic modelling studies, such as predicted survival probabilities and model performance measures. Methods Guidelines for combining the estimates of interest when analysing prognostic modelling studies are provided. A literature review is performed to identify current practice for combining such estimates in prognostic modelling studies. Results Methods for combining all reported estimates after MI were not well reported in the current literature. Rubin's rules without applying any transformations were the standard approach used, when any method was stated. Conclusion The proposed simple guidelines for combining estimates after MI may lead to a wider and more appropriate use of MI in future prognostic modelling studies.

  2. RooStatsCms: a tool for analyses modelling, combination and statistical studies

    Science.gov (United States)

    Piparo, D.; Schott, G.; Quast, G.

    2009-12-01

    The RooStatsCms (RSC) software framework allows analysis modelling and combination, statistical studies together with the access to sophisticated graphics routines for results visualisation. The goal of the project is to complement the existing analyses by means of their combination and accurate statistical studies.

  3. RooStatsCms: a tool for analyses modelling, combination and statistical studies

    CERN Document Server

    Piparo, D; Quast, Prof G

    2008-01-01

    The RooStatsCms (RSC) software framework allows analysis modelling and combination, statistical studies together with the access to sophisticated graphics routines for results visualisation. The goal of the project is to complement the existing analyses by means of their combination and accurate statistical studies.

  4. Bayesian hierarchical models combining different study types and adjusting for covariate imbalances: a simulation study to assess model performance.

    Directory of Open Access Journals (Sweden)

    C Elizabeth McCarron

    Full Text Available BACKGROUND: Bayesian hierarchical models have been proposed to combine evidence from different types of study designs. However, when combining evidence from randomised and non-randomised controlled studies, imbalances in patient characteristics between study arms may bias the results. The objective of this study was to assess the performance of a proposed Bayesian approach to adjust for imbalances in patient level covariates when combining evidence from both types of study designs. METHODOLOGY/PRINCIPAL FINDINGS: Simulation techniques, in which the truth is known, were used to generate sets of data for randomised and non-randomised studies. Covariate imbalances between study arms were introduced in the non-randomised studies. The performance of the Bayesian hierarchical model adjusted for imbalances was assessed in terms of bias. The data were also modelled using three other Bayesian approaches for synthesising evidence from randomised and non-randomised studies. The simulations considered six scenarios aimed at assessing the sensitivity of the results to changes in the impact of the imbalances and the relative number and size of studies of each type. For all six scenarios considered, the Bayesian hierarchical model adjusted for differences within studies gave results that were unbiased and closest to the true value compared to the other models. CONCLUSIONS/SIGNIFICANCE: Where informed health care decision making requires the synthesis of evidence from randomised and non-randomised study designs, the proposed hierarchical Bayesian method adjusted for differences in patient characteristics between study arms may facilitate the optimal use of all available evidence leading to unbiased results compared to unadjusted analyses.

  5. Combined experimental and computational modelling studies of the solubility of nickel in strontium titanate

    NARCIS (Netherlands)

    Beale, A.M.; Paul, M.; Sankar, G.; Oldman, R.J.; Catlow, R.A.; French, S.; Fowles, M.

    2009-01-01

    A combination of X-ray techniques and atomistic computational modelling has been used to study the solubility of Ni in SrTiO3 in relation to the application of this material for the catalytic partial oxidation of methane. The experiments have demonstrated that low temperature, hydrothermal synthesis

  6. A Case Study on a Combination NDVI Forecasting Model Based on the Entropy Weight Method

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Shengzhi; Ming, Bo; Huang, Qiang; Leng, Guoyong; Hou, Beibei

    2017-05-05

    It is critically meaningful to accurately predict NDVI (Normalized Difference Vegetation Index), which helps guide regional ecological remediation and environmental managements. In this study, a combination forecasting model (CFM) was proposed to improve the performance of NDVI predictions in the Yellow River Basin (YRB) based on three individual forecasting models, i.e., the Multiple Linear Regression (MLR), Artificial Neural Network (ANN), and Support Vector Machine (SVM) models. The entropy weight method was employed to determine the weight coefficient for each individual model depending on its predictive performance. Results showed that: (1) ANN exhibits the highest fitting capability among the four orecasting models in the calibration period, whilst its generalization ability becomes weak in the validation period; MLR has a poor performance in both calibration and validation periods; the predicted results of CFM in the calibration period have the highest stability; (2) CFM generally outperforms all individual models in the validation period, and can improve the reliability and stability of predicted results through combining the strengths while reducing the weaknesses of individual models; (3) the performances of all forecasting models are better in dense vegetation areas than in sparse vegetation areas.

  7. Model heterogeneous acid catalysts and metal-support interactions: A combined surface science and catalysis study

    Energy Technology Data Exchange (ETDEWEB)

    Boszormenyi, I.

    1991-05-01

    This (<100 [Angstrom]) silica-alumina layers were tested as potential model heterogeneous acid catalysts for combined surface science and catalysis studies. Three preparation methods were used: oxidation of r3 [times] r3 R30 Al/Si(111) structure in UHV; deposition on Si(lll) from aqueous solution; and argon ion beam sputter deposition in UHV. The homogeneous thin layers are amorphous, and the chemical environment of surface atoms is similar to that of Si, Al and oxygen atoms on high surface area acid catalysts. Since the ion beam-deposited thin layer of silica-alumina has the same composition as the target zeolite this deposition method is a promising tool to prepare model catalysts using practical catalyst targets. The silica-alumina layers are active in cumene cracking, a typical acid catalyzed reaction. In order to clearly distinguish background reactions and the acid catalyzed reaction at least 20 cm[sup 2] catalyst surface area is needed. Two series of model platinum-alumina catalysts were prepared in a combined UHV -- high pressure reactor cell apparatus by depositing alumina on polycrystalline Pt foil and by vapor depositing Pt on a thin alumina layer on Au. Both model surfaces have been prepared with and without chlorine. AES, CO desorption as well as methyl cyclopentane (MCP) hydrogenolysis studies indicate that the Pt surface area is always higher if a chlorination step is involved. Selectivity patterns in MCP ring opening on Pt-on-alumina'' and on alumina-on-Pt'' are different; only the former is a linear combination of selective and statistical ring opening. Product distribution, however, changes with coverage and reaction time. The properties of the two model catalyst systems and role of chlorine in MCP hydrogenolysis are also discussed.

  8. Model heterogeneous acid catalysts and metal-support interactions: A combined surface science and catalysis study

    Energy Technology Data Exchange (ETDEWEB)

    Boszormenyi, I.

    1991-05-01

    This (<100 {Angstrom}) silica-alumina layers were tested as potential model heterogeneous acid catalysts for combined surface science and catalysis studies. Three preparation methods were used: oxidation of r3 {times} r3 R30 Al/Si(111) structure in UHV; deposition on Si(lll) from aqueous solution; and argon ion beam sputter deposition in UHV. The homogeneous thin layers are amorphous, and the chemical environment of surface atoms is similar to that of Si, Al and oxygen atoms on high surface area acid catalysts. Since the ion beam-deposited thin layer of silica-alumina has the same composition as the target zeolite this deposition method is a promising tool to prepare model catalysts using practical catalyst targets. The silica-alumina layers are active in cumene cracking, a typical acid catalyzed reaction. In order to clearly distinguish background reactions and the acid catalyzed reaction at least 20 cm{sup 2} catalyst surface area is needed. Two series of model platinum-alumina catalysts were prepared in a combined UHV -- high pressure reactor cell apparatus by depositing alumina on polycrystalline Pt foil and by vapor depositing Pt on a thin alumina layer on Au. Both model surfaces have been prepared with and without chlorine. AES, CO desorption as well as methyl cyclopentane (MCP) hydrogenolysis studies indicate that the Pt surface area is always higher if a chlorination step is involved. Selectivity patterns in MCP ring opening on ``Pt-on-alumina`` and on ``alumina-on-Pt`` are different; only the former is a linear combination of selective and statistical ring opening. Product distribution, however, changes with coverage and reaction time. The properties of the two model catalyst systems and role of chlorine in MCP hydrogenolysis are also discussed.

  9. Model study of combined electrical and near-infrared neural stimulation on the bullfrog sciatic nerve.

    Science.gov (United States)

    You, Mengxian; Mou, Zongxia

    2017-07-01

    This paper implemented a model study of combined electrical and near-infrared (808 nm) neural stimulation (NINS) on the bullfrog sciatic nerve. The model includes a COMSOL model to calculate the electric-field distribution of the surrounding area of the nerve, a Monte Carlo model to simulate light transport and absorption in the bullfrog sciatic nerve during NINS, and a NEURON model to simulate the neural electrophysiology changes under electrical stimulus and laser irradiation. The optical thermal effect is considered the main mechanism during NINS. Therefore, thermal change during laser irradiation was calculated by the Monte Carlo method, and the temperature distribution was then transferred to the NEURON model to stimulate the sciatic nerve. The effects on thermal response by adjusting the laser spot size, energy of the beam, and the absorption coefficient of the nerve are analyzed. The effect of the ambient temperature on the electrical stimulation or laser stimulation and the interaction between laser irradiation and electrical stimulation are also studied. The results indicate that the needed stimulus threshold for neural activation or inhibition is reduced by laser irradiation. Additionally, the needed laser energy for blocking the action potential is reduced by electrical stimulus. Both electrical and laser stimulation are affected by the ambient temperature. These results provide references for subsequent animal experiments and could be of great help to future basic and applied studies of infrared neural stimulation (INS).

  10. Tunneling of electrons via rotor-stator molecular interfaces: combined ab initio and model study

    CERN Document Server

    Petreska, Irina; Pejov, Ljupco; Kocarev, Ljupco

    2015-01-01

    Tunneling of electrons through rotor-stator anthracene aldehyde molecular interfaces is studied with a combined ab initio and model approach. Molecular electronic structure calculated from first principles is utilized to model different shapes of tunneling barriers. Together with a rectangular barrier, we also consider a sinusoidal shape that captures the effects of the molecular internal structure more realistically. Quasiclassical approach with the Simmons' formula for current density is implemented. Special attention is paid on conformational dependence of the tunneling current. Our results confirm that the presence of the side aldehyde group enhances the interesting electronic properties of the pure anthracene molecule, making it a bistable system with geometry dependent transport properties. We also investigate the transition voltage and we show that confirmation dependent field emission could be observed in these molecular interfaces at realistically low voltages. The present study accompanies our previ...

  11. Bioremediation in marine ecosystems: a computational study combining ecological modelling and flux balance analysis

    Directory of Open Access Journals (Sweden)

    Marianna eTaffi

    2014-09-01

    Full Text Available The pressure to search effective bioremediation methodologies for contaminated ecosystems has led to the large-scale identification of microbial species and metabolic degradation pathways. However, minor attention has been paid to the study of bioremediation in marine food webs and to the definition of integrated strategies for reducing bioaccumulation in species. We propose a novel computational framework for analysing the multiscale effects of bioremediation at the ecosystem level, based on coupling food web bioaccumulation models and metabolic models of degrading bacteria. The combination of techniques from synthetic biology and ecological network analysis allows the specification of arbitrary scenarios of contaminant removal and the evaluation of strategies based on natural or synthetic microbial strains.In this study, we derive a bioaccumulation model of polychlorinated biphenyls (PCBs in the Adriatic food web, and we extend a metabolic reconstruction of Pseudomonas putida KT2440 (iJN746 with the aerobic pathway of PCBs degradation. We assess the effectiveness of different bioremediation scenarios in reducing PCBs concentration in species and we study indices of species centrality to measure their importance in the contaminant diffusion via feeding links.The analysis of the Adriatic sea case study suggests that our framework could represent a practical tool in the design of effective remediation strategies, providing at the same time insights into the ecological role of microbial communities within food webs.

  12. Bioremediation in marine ecosystems: a computational study combining ecological modeling and flux balance analysis.

    Science.gov (United States)

    Taffi, Marianna; Paoletti, Nicola; Angione, Claudio; Pucciarelli, Sandra; Marini, Mauro; Liò, Pietro

    2014-01-01

    The pressure to search effective bioremediation methodologies for contaminated ecosystems has led to the large-scale identification of microbial species and metabolic degradation pathways. However, minor attention has been paid to the study of bioremediation in marine food webs and to the definition of integrated strategies for reducing bioaccumulation in species. We propose a novel computational framework for analysing the multiscale effects of bioremediation at the ecosystem level, based on coupling food web bioaccumulation models and metabolic models of degrading bacteria. The combination of techniques from synthetic biology and ecological network analysis allows the specification of arbitrary scenarios of contaminant removal and the evaluation of strategies based on natural or synthetic microbial strains. In this study, we derive a bioaccumulation model of polychlorinated biphenyls (PCBs) in the Adriatic food web, and we extend a metabolic reconstruction of Pseudomonas putida KT2440 (iJN746) with the aerobic pathway of PCBs degradation. We assess the effectiveness of different bioremediation scenarios in reducing PCBs concentration in species and we study indices of species centrality to measure their importance in the contaminant diffusion via feeding links. The analysis of the Adriatic sea case study suggests that our framework could represent a practical tool in the design of effective remediation strategies, providing at the same time insights into the ecological role of microbial communities within food webs.

  13. Adsorption of mercury on lignin: combined surface complexation modeling and X-ray absorption spectroscopy studies.

    Science.gov (United States)

    Lv, Jitao; Luo, Lei; Zhang, Jing; Christie, Peter; Zhang, Shuzhen

    2012-03-01

    Adsorption of mercury (Hg) on lignin was studied at a range of pH values using a combination of batch adsorption experiments, a surface complexation model (SCM) and synchrotron X-ray absorption spectroscopy (XAS). Surface complexation modeling indicates that three types of acid sites on lignin surfaces, namely aliphatic carboxylic-, aromatic carboxylic- and phenolic-type surface groups, contributed to Hg(II) adsorption. The bond distance and coordination number of Hg(II) adsorption samples at pH 3.0, 4.0 and 5.5 were obtained from extended X-ray absorption fine structure (EXAFS) spectroscopy analysis. The results of SCM and XAS combined reveal that the predominant adsorption species of Hg(II) on lignin changes from HgCl(2)(0) to monodentate complex -C-O-HgCl and then bidentate complex -C-O-Hg-O-C- with increasing pH value from 2.0 to 6.0. The good agreement between SCM and XAS results provides new insight into understanding the mechanisms of Hg(II) adsorption on lignin.

  14. Improving the analysis of designed studies by combining statistical modelling with study design information

    NARCIS (Netherlands)

    Thissen, U.; Wopereis, S.; van Berg, S.A.A.; Bobeldijk, I.; Kleemann, R.; Kooistra, T.; van Dijk, K.W.; van Ommen, B.; Smilde, A.K.

    2009-01-01

    Background: In the fields of life sciences, so-called designed studies are used for studying complex biological systems. The data derived from these studies comply with a study design aimed at generating relevant information while diminishing unwanted variation (noise). Knowledge about the study

  15. Tunneling of electrons via rotor-stator molecular interfaces: Combined ab initio and model study

    Science.gov (United States)

    Petreska, Irina; Ohanesjan, Vladimir; Pejov, Ljupčo; Kocarev, Ljupčo

    2016-07-01

    Tunneling of electrons through rotor-stator anthracene aldehyde molecular interfaces is studied with a combined ab initio and model approach. Molecular electronic structure calculated from first principles is utilized to model different shapes of tunneling barriers. Together with a rectangular barrier, we also consider a sinusoidal shape that captures the effects of the molecular internal structure more realistically. Quasiclassical approach with the Simmons' formula for current density is implemented. Special attention is paid on conformational dependence of the tunneling current. Our results confirm that the presence of the side aldehyde group enhances the interesting electronic properties of the pure anthracene molecule, making it a bistable system with geometry dependent transport properties. We also investigate the transition voltage and we show that conformation-dependent field emission could be observed in these molecular interfaces at realistically low voltages. The present study accompanies our previous work where we investigated the coherent transport via strongly coupled delocalized orbital by application of Non-equilibrium Green's Function Formalism.

  16. Combined Treatment Effects of Radiation and Immunotherapy: Studies in an Autochthonous Prostate Cancer Model

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Satoshi [Department of Oncology, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Harris, Timothy J.; Tryggestad, Erik [Department of Radiation Oncology and Molecular Radiation Sciences, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Yoshimura, Kiyoshi [Department of Oncology, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Zeng, Jing [Department of Radiation Oncology and Molecular Radiation Sciences, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Yen, Hung-Rong; Getnet, Derese; Grosso, Joseph F.; Bruno, Tullia C. [Department of Oncology, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); De Marzo, Angelo M. [Department of Pathology, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); and others

    2013-11-15

    Purpose: To optimize the combination of ionizing radiation and cellular immunotherapy using a preclinical autochthonous model of prostate cancer. Methods and Materials: Transgenic mice expressing a model antigen under a prostate-specific promoter were treated using a platform that integrates cone-beam CT imaging with 3-dimensional conformal therapy. Using this technology we investigated the immunologic and therapeutic effects of combining ionizing radiation with granulocyte/macrophage colony-stimulating factor-secreting cellular immunotherapy for prostate cancer in mice bearing autochthonous prostate tumors. Results: The combination of ionizing radiation and immunotherapy resulted in a significant decrease in pathologic tumor grade and gross tumor bulk that was not evident with either single-modality therapy. Furthermore, combinatorial therapy resulted in improved overall survival in a preventive metastasis model and in the setting of established micrometastases. Mechanistically, combined therapy resulted in an increase of the ratio of effector-to-regulatory T cells for both CD4 and CD8 tumor-infiltrating lymphocytes. Conclusions: Our preclinical model establishes a potential role for the use of combined radiation-immunotherapy in locally advanced prostate cancer, which warrants further exploration in a clinical setting.

  17. Theoretical Study on Stochastic Modeling of Combined Gravity-Magnetic-Electric-Seismic Inversion and Its Application

    Institute of Scientific and Technical Information of China (English)

    Yan Hanjie; Yan Hong; Li Yunping; Zhang Xiaofeng

    2003-01-01

    As gravity field, magnetic field, electric field and reismic wave field are all physical fields, their object function, reverse function and compound function are certainly infinite continuously differentiable functions which can be expanded into Taylor (Fourier) series within domain of definition and be further reduced into solving stochastic distribution function of series and statistic inference of optimal approximation. This is thebasis of combined gravity-magnetic-electric-seismic inversion of stochastic modeling. It is an uncertainty modeling technology of combining gravity-magnetic-electric-seismic inversion built on the basis of separation of field and source gravity-magnetic difference-value (D-value) trend surface, taking distribution-independent fault system as its unit, depths of seismic and electric interfaces of interests as its corresponding bivariate compound reverse function of gravity-magnetic anomalies and using high order polynomial (high order trigonometric function) approximating to its series distribution. The difference from current dominant inversion techniques is that, first, it does not respectively create gravity-seismic, magnetic-seismic deterministic inversion model from theoretical model, but combines gravity-magnetic-electric-seismic stochastic inversion model from stochastic model; second, after the concept of equivalent geological body being introduced, using feature of independent variable of gravity-magnetic field functions, taking density and susceptibility related to gravity-magnetic function as default parameters of model, the deterministic model is established owing to better solution to the contradiction of difficulty in identifying strata and less test analytical data for density and susceptibility in newly explored area; third, under assumption of independent parent distribution, a real modeling by strata, the problem of difficult plane closure arising in profile modeling is avoided. This technology has richer and more

  18. Gene Therapy Studies in a Canine Model of X-Linked Severe Combined Immunodeficiency

    Science.gov (United States)

    De Ravin, Suk See; Malech, Harry L.; Sorrentino, Brian P.; Burtner, Christopher; Kiem, Hans-Peter

    2015-01-01

    Abstract Since the occurrence of T cell leukemias in the original human γ-retroviral gene therapy trials for X-linked severe combined immunodeficiency (XSCID), considerable effort has been devoted to developing safer vectors. This review summarizes gene therapy studies performed in a canine model of XSCID to evaluate the efficacy of γ-retroviral, lentiviral, and foamy viral vectors for treating XSCID and a novel method of vector delivery. These studies demonstrate that durable T cell reconstitution and thymopoiesis with no evidence of any serious adverse events and, in contrast to the human XSCID patients, sustained marking in myeloid cells and B cells with reconstitution of normal humoral immune function can be achieved for up to 5 years without any pretreatment conditioning. The presence of sustained levels of gene-marked T cells, B cells, and more importantly myeloid cells for almost 5 years is highly suggestive of transduction of either multipotent hematopoietic stem cells or very primitive committed progenitors. PMID:25603151

  19. On Chemical Modeling an Alchemical Process: The Use of Combined Chemical Methods in a Historical Study

    Science.gov (United States)

    Rodygin, Mikhail Yu.; Rodygin, Irene V.

    1997-08-01

    Laboratory work is an important component of a course in the History of Chemistry and Alchemy, though it can only be illustrative and not comprehensive. The course should exercise both the cognitive and research abilities of an university student. Therefore methods of modeling are of prime importance at this stage of instruction. Modeling can be both a priori and experimental. The experiment can use the alchemist's materials, or it can reproduce the procedure with modern reagents. A good example for the use of this method is a recipe for the preparation of the Philosopher's Stone attributed to Lullius and cited by J. Ripley in Liber Duodecium Portarum. Thus, the Ripley's recipe is not only considered to be the first indication of the existence of acetone, but it may also indicate the formation of acetyl acetone and its derivatives. Thus, as far as the history of alchemy is concerned, the use of an experimental model not only allows us to solve a number of specific problems such as recipe interpretation and product identification, but it allows also to probe the essence of alchemical work. The combination of empirical and speculative modelings leads to the interaction of the exact methods of chemistry with the broad historico-chemical generalizations, thus introducing some additional dimensions to the definition of historico-chemical practice.

  20. Combining Model-Based and Feature-Driven Diagnosis Approaches - A Case Study on Electromechanical Actuators

    Science.gov (United States)

    Narasimhan, Sriram; Roychoudhury, Indranil; Balaban, Edward; Saxena, Abhinav

    2010-01-01

    Model-based diagnosis typically uses analytical redundancy to compare predictions from a model against observations from the system being diagnosed. However this approach does not work very well when it is not feasible to create analytic relations describing all the observed data, e.g., for vibration data which is usually sampled at very high rates and requires very detailed finite element models to describe its behavior. In such cases, features (in time and frequency domains) that contain diagnostic information are extracted from the data. Since this is a computationally intensive process, it is not efficient to extract all the features all the time. In this paper we present an approach that combines the analytic model-based and feature-driven diagnosis approaches. The analytic approach is used to reduce the set of possible faults and then features are chosen to best distinguish among the remaining faults. We describe an implementation of this approach on the Flyable Electro-mechanical Actuator (FLEA) test bed.

  1. Exploring survey participation, data combination, and research validity in a substance use study: an application of hierarchical linear modeling.

    Science.gov (United States)

    Orsi, Rebecca; Chapman, Phillip L; Edwards, Ruth W

    2010-01-01

    A sound decision regarding combination of datasets is critical for research validity. Data were collected between 1996 and 2000 via a 99-item survey of substance use behaviors. Two groups of 7th-12th grade students in predominately White communities are compared: 166,578 students from 193 communities with high survey participation and 41,259 students from 65 communities with lower participation. Hierarchical logistic models are used to explore whether the two datasets may be combined for further study of community-level substance use effects. "Scenario analysis" is introduced. Results suggest the datasets may reasonably be combined. Limitations and further research are discussed.

  2. Combining classical metrology models

    Directory of Open Access Journals (Sweden)

    Francisco Roldán

    2013-11-01

    Full Text Available The results obtained in the graphic analysis of the modulation of the Cuarto Real de Santo Domingo building in Granada, Spain, (ROLDÁN, 2011 have provided new insights to further approach the research on possible use the double-scale in historical monumental architecture. We propose the characterization of the singularities of the system, from the implications and graphic representation required by the metrological scheme identified, as well as the variety of typologies that are presented in their modular frames, and the iterative combination of two-scale modules which allow operational approximations to fractions and ratios not explicitly present in the system.

  3. Recrystallization and texture evolution during hot rolling of copper, studied by a multiscale model combining crystal plasticity and vertex models

    Science.gov (United States)

    Mellbin, Y.; Hallberg, H.; Ristinmaa, M.

    2016-10-01

    A multiscale modeling framework, combining a graph-based vertex model of microstructure evolution with a GPU-parallelized crystal plasticity model, was recently proposed by the authors. Considering hot rolling of copper, the full capabilities of the model are demonstrated in the present work. The polycrystal plasticity model captures the plastic response and the texture evolution during materials processing while the vertex model provides central features of grain structure evolution through dynamic recrystallization, such as nucleation and growth of individual crystals. The multiscale model makes it possible to obtain information regarding grain size and texture development throughout the workpiece, capturing the effects of recrystallization and heterogeneous microstructure evolution. Recognizing that recrystallization is a highly temperature dependent phenomenon, simulations are performed at different process temperatures. The results show that the proposed modeling framework is capable of simultaneously capturing central aspects of material behavior at both the meso- and macrolevel. Detailed investigation of the evolution of texture, grain size distribution and plastic deformation during the different processing conditions are performed, using the proposed model. The results show a strong texture development, but almost no recrystallization, for the lower of the investigated temperatures, while at higher temperatures an increased recrystallization is shown to weaken the development of a typical rolling texture. The simulations also show the influence of the shear deformation close to the rolling surface on both texture development and recrystallization.

  4. Influence of Hofmeister Ions on the Structure of Proline-Based Peptide Models: A Combined Experimental and Molecular Modeling Study.

    Science.gov (United States)

    Bröhl, Andreas; Albrecht, Benjamin; Zhang, Yong; Maginn, Edward; Giernoth, Ralf

    2017-02-23

    The influence of three sodium salts, covering a wide range of the Hofmeister series, on the conformation of three proline-based peptide models in aqueous solution is examined using a combination of nuclear magnetic resonance spectroscopy and molecular dynamics simulations. The anions preferentially interact with the cis conformers of the peptide models, which is rationalized by the respective electrostatic potential surfaces. These preferred interactions have a strong impact on the thermodynamics of the cis/trans equilibria, leading to a higher population of the cis conformers. In distinct cases, these equilibria are nearly independent of temperature, showing that the salts are also able to stabilize the conformers over wide temperature ranges.

  5. Experimental and Pathalogical study of Pistacia atlantica, butyrate, Lactobacillus casei and their combination on rat ulcerative colitis model.

    Science.gov (United States)

    Gholami, Mahdi; Ghasemi-Niri, Seyedeh Farnaz; Maqbool, Faheem; Baeeri, Maryam; Memariani, Zahra; Pousti, Iraj; Abdollahi, Mohammad

    2016-06-01

    This study evaluated the effects of Pistacia atlantica (P. atlantica), butyrate, Lactobacillus casei (L. casei) and especially their combination therapy on 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced rat colitis model. Rats were divided into seven groups. Four groups received oral P. atlantica, butyrate, L. casei and the combination of three agents for 10 consecutive days. The remaining groups were negative and positive controls and a sham group. Macroscopic and histopathological examinations were carried out along with determination of the specific biomarker of colonic oxidative stress, the myeloperoxidase (MPO). Compared with controls, the combination therapy exhibited a significant alleviation of colitis in terms of pathological scores and reduction of MPO activity (55%, p=0.0009). Meanwhile, the macroscopic appearance such as stool consistency, tissue and histopathological scores (edema, necrosis and neutrophil infiltration) were improved. Although single therapy by each P. atlantica, butyrate, and L. casei was partially beneficial in reduction of colon oxidative stress markers, the combination therapy was much more effective. In conclusion, the combination therapy was able to reduce the severity of colitis that is clear from biochemical markers. Future studies have to focus on clinical effects of this combination in management of human ulcerative colitis. Further molecular and signaling pathway studies will help to understand the mechanisms involved in the treatment of colitis and inflammatory diseases.

  6. PrEP for key populations in combination HIV prevention in Nairobi: a mathematical modelling study.

    Science.gov (United States)

    Cremin, Ide; McKinnon, Lyle; Kimani, Joshua; Cherutich, Peter; Gakii, Gloria; Muriuki, Festus; Kripke, Katharine; Hecht, Robert; Kiragu, Michael; Smith, Jennifer; Hinsley, Wes; Gelmon, Lawrence; Hallett, Timothy B

    2017-05-01

    The HIV epidemic in the population of Nairobi as a whole is in decline, but a concentrated sub-epidemic persists in key populations. We aimed to identify an optimal portfolio of interventions to reduce HIV incidence for a given budget and to identify the circumstances in which pre-exposure prophylaxis (PrEP) could be used in Nairobi, Kenya. A mathematical model was developed to represent HIV transmission in specific key populations (female sex workers, male sex workers, and men who have sex with men [MSM]) and among the wider population of Nairobi. The scale-up of existing interventions (condom promotion, antiretroviral therapy, and male circumcision) for key populations and the wider population as have occurred in Nairobi is represented. The model includes a detailed representation of a PrEP intervention and is calibrated to prevalence and incidence estimates specific to key populations and the wider population. In the context of a declining epidemic overall but with a large sub-epidemic in MSM and male sex workers, an optimal prevention portfolio for Nairobi should focus on condom promotion for male sex workers and MSM in particular, followed by improved antiretroviral therapy retention, earlier antiretroviral therapy, and male circumcision as the budget allows. PrEP for male sex workers could enter an optimal portfolio at similar levels of spending to when earlier antiretroviral therapy is included; however, PrEP for MSM and female sex workers would be included only at much higher budgets. If PrEP for male sex workers cost as much as US$500, average annual spending on the interventions modelled would need to be less than $3·27 million for PrEP for male sex workers to be excluded from an optimal portfolio. Estimated costs per infection averted when providing PrEP to all female sex workers regardless of their risk of infection, and to high-risk female sex workers only, are $65 160 (95% credible interval [CrI] $43 520-$90 250) and $10 920 (95% CrI $4700

  7. Combining modeling and monitoring to study fecal contamination in a small rural catchment.

    Science.gov (United States)

    Bougeard, Morgane; Le Saux, Jean-Claude; Teillon, Anna; Belloir, Jérôme; Le Mennec, Cécile; Thome, Sterenn; Durand, Gael; Pommepuy, Monique

    2011-09-01

    The present study sought to identify Escherichia coli sources in a small catchment and to use the agro-hydrological model soil and water assessment tool (SWAT) to estimate their impact on river water quality. The innovative aspects of this research are to assess the hourly variations of fecal contamination and to take these variations into account in the model to provide a better evaluation of river quality. Thus, water samples were taken weekly at the river outlet (n = 4) and 24-h monitoring sessions were performed during low and high-flow periods (n = 74). E. coli variations were found to be primarily linked to rainfall and not to resuspension mechanisms. Subdaily fluctuations and deviations were ±0.33 log(10) cfu/100 mL and ±0.70 log(10) cfu/100 mL for dry (3 mm/day) weather, respectively. After river flow calibration, all known pollution sources (septic systems, manure spreading, farm discharges) were introduced into SWAT. The model reproduced the fecal contamination in the river and the use of subdaily deviations allowed us to evaluate the simulation quality and compare grab samplings with simulated daily E. coli concentration, thus confirming that the performance of the model is better when additional information on hourly concentration variations is used.

  8. Study of establishing disease-syndrome combined with animal model for immune thrombocytopenic purpura without additional conditions

    Directory of Open Access Journals (Sweden)

    Haiyan Lang

    2016-07-01

    Conclusion: According to the syndrome differentiation criteria for disease-syndrome combined model of ITP, the APS-injected animal model of ITP replicated through the passive immune modeling method without additional conditions possesses the characteristics of disease-syndrome combined model. It provides an ideal tool for the development of traditional Chinese medicine pharmacology experiment.

  9. A combined modelling and experimental study of the surface energetics of alpha-lactose monohydrate.

    Science.gov (United States)

    Saxena, A; Kendrick, J; Grimsey, I M; Roberts, R; York, P

    2010-02-01

    The surface energy of alpha-lactose monohydrate measured by inverse gas chromatography (IGC) is reported along with a dynamic molecular modelling study of the interaction of the various molecular probes with different surfaces of alpha-lactose monohydrate. The IGC results show that alpha-lactose monohydrate is acidic in nature. Using quantitative calculations of the energy of adsorption, the acidic nature of the surface is confirmed and the calculated values agree closely with the experimentally measured values. Along with the acidic nature, dynamic molecular modelling also reveals that the presence of a channel and water molecules on a surface affects the surface energetics of that face. The presence of water on the surface can decrease or increase the surface energy by either blocking or attracting a probe molecule, respectively. This property of water depends on its position and association with other functional groups present on the surface. The effect of a channel or cavity on the surface energy is shown to depend on its size, which determines whether the functional groups in the channel are assessable by probe molecules or not. Overall molecular modelling explains, at the molecular level, the effect of different factors affecting the surface energy of individual faces of the crystal. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association.

  10. Study on the combined influence of battery models and sizing strategy for hybrid and battery-based electric vehicles

    DEFF Research Database (Denmark)

    Pinto, Cláudio; Barreras, Jorge V.; de Castro, Ricardo

    2017-01-01

    This paper presents a study of the combined influence of battery models and sizing strategy for hybrid and battery-based electric vehicles. In particular, the aim is to find the number of battery (and supercapacitor) cells to propel a light vehicle to run two different standard driving cycles....... Despite the same tendency, when a hybrid vehicle is taken into account, the influence of the battery models is dependent on the sizing strategy. In this work, two sizing strategies are evaluated: dynamic programming and filter-based. For the latter, the complexity of the battery model has a clear....... Three equivalent circuit models are considered to simulate the battery electrical performance: linear static, non-linear static and non-linear with first-order dynamics. When dimensioning a battery-based vehicle, less complex models may lead to a solution with more battery cells and higher costs...

  11. Prevention and Intervention Studies with Telmisartan, Ramipril and Their Combination in Different Rat Stroke Models

    Science.gov (United States)

    Schmerbach, Kristin; Krikov, Maxim; Wengenmayer, Christina; Godes, Michael; Mueller, Susanne; Villringer, Arno; Steckelings, Ulrike

    2011-01-01

    Objectives The effects of AT1 receptor blocker, telmisartan, and the ACE inhibitor, ramipril, were tested head-to head and in combination on stroke prevention in hypertensive rats and on potential neuroprotection in acute cerebral ischemia in normotensive rats. Methods Prevention study: Stroke-prone spontaneously hypertensive rats (SHR-SP) were subjected to high salt and randomly assigned to 4 groups: (1) untreated (NaCl, n = 24), (2) telmisartan (T; n = 27), (3) ramipril (R; n = 27) and (4) telmisartan +ramipril (T+R; n = 26). Drug doses were selected to keep blood pressure (BP) at 150 mmHg in all groups. Neurological signs and stroke incidence at 50% mortality of untreated SHR-SP were investigated. Intervention study: Normotensive Wistar rats were treated s.c. 5 days prior to middle cerebral artery occlusion (MCAO) for 90 min with reperfusion. Groups (n = 10 each): (1) sham, (2) vehicle (V; 0,9% NaCl), (3) T (0,5 mg/kg once daily), (4) R (0,01 mg/kg twice daily), (5) R (0,1 mg/kg twice daily) or (6) T (0,5 mg/kg once daily) plus R (0,01 mg/kg twice daily). Twenty-four and 48 h after MCAO, neurological outcome (NO) was determined. Forty-eight h after MCAO, infarct volume by MRI, neuronal survival, inflammation factors and neurotrophin receptor (TrkB) were analysed. Results Stroke incidence was reduced, survival was prolonged and neurological outcome was improved in all treated SHR-SP with no differences between treated groups. In the acute intervention study, T and T+R, but not R alone, improved NO, reduced infarct volume, inflammation (TNFα), and induced TrkB receptor and neuronal survival in comparison to V. Conclusions T, R or T+R had similar beneficial effects on stroke incidence and NO in hypertensive rats, confirming BP reduction as determinant factor in stroke prevention. In contrast, T and T+R provided superior neuroprotection in comparison to R alone in normotensive rats with induced cerebral ischemia. PMID:21901125

  12. Prevention and intervention studies with telmisartan, ramipril and their combination in different rat stroke models.

    Directory of Open Access Journals (Sweden)

    Christa Thoene-Reineke

    Full Text Available OBJECTIVES: The effects of AT1 receptor blocker, telmisartan, and the ACE inhibitor, ramipril, were tested head-to head and in combination on stroke prevention in hypertensive rats and on potential neuroprotection in acute cerebral ischemia in normotensive rats. METHODS: Prevention study: Stroke-prone spontaneously hypertensive rats (SHR-SP were subjected to high salt and randomly assigned to 4 groups: (1 untreated (NaCl, n = 24, (2 telmisartan (T; n = 27, (3 ramipril (R; n = 27 and (4 telmisartan + ramipril (T+R; n = 26. Drug doses were selected to keep blood pressure (BP at 150 mmHg in all groups. Neurological signs and stroke incidence at 50% mortality of untreated SHR-SP were investigated. Intervention study: Normotensive Wistar rats were treated s.c. 5 days prior to middle cerebral artery occlusion (MCAO for 90 min with reperfusion. Groups (n = 10 each: (1 sham, (2 vehicle (V; 0.9% NaCl, (3 T (0.5 mg/kg once daily, (4 R (0.01 mg/kg twice daily, (5 R (0.1 mg/kg twice daily or (6 T (0.5 mg/kg once daily plus R (0.01 mg/kg twice daily. Twenty-four and 48 h after MCAO, neurological outcome (NO was determined. Forty-eight h after MCAO, infarct volume by MRI, neuronal survival, inflammation factors and neurotrophin receptor (TrkB were analysed. RESULTS: Stroke incidence was reduced, survival was prolonged and neurological outcome was improved in all treated SHR-SP with no differences between treated groups. In the acute intervention study, T and T+R, but not R alone, improved NO, reduced infarct volume, inflammation (TNFα, and induced TrkB receptor and neuronal survival in comparison to V. CONCLUSIONS: T, R or T+R had similar beneficial effects on stroke incidence and NO in hypertensive rats, confirming BP reduction as determinant factor in stroke prevention. In contrast, T and T+R provided superior neuroprotection in comparison to R alone in normotensive rats with induced cerebral ischemia.

  13. Combined 3D-QSAR modeling and molecular docking study on azacycles CCR5 antagonists

    Science.gov (United States)

    Ji, Yongjun; Shu, Mao; Lin, Yong; Wang, Yuanqiang; Wang, Rui; Hu, Yong; Lin, Zhihua

    2013-08-01

    The beta chemokine receptor 5 (CCR5) is an attractive target for pharmaceutical industry in the HIV-1, inflammation and cancer therapeutic areas. In this study, we have developed quantitative structure activity relationship (QSAR) models for a series of 41 azacycles CCR5 antagonists using comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA), and Topomer CoMFA methods. The cross-validated coefficient q2 values of 3D-QASR (CoMFA, CoMSIA, and Topomer CoMFA) methods were 0.630, 0.758, and 0.852, respectively, the non-cross-validated R2 values were 0.979, 0.978, and 0.990, respectively. Docking studies were also employed to determine the most probable binding mode. 3D contour maps and docking results suggested that bulky groups and electron-withdrawing groups on the core part would decrease antiviral activity. Furthermore, docking results indicated that H-bonds and π bonds were favorable for antiviral activities. Finally, a set of novel derivatives with predicted activities were designed.

  14. EFFECT OF A COMBINED CHLORHEXIDINE AND NAF MOUTHRINSE - AN IN-VIVO HUMAN CARIES MODEL STUDY

    NARCIS (Netherlands)

    ULLSFOSS, BN; OGAARD, B; ARENDS, J; RUBEN, J; ROLLA, G; AFSETH, J

    1994-01-01

    Chlorhexidine (CHX) is probably the most widely used and the most potent chemical plaque inhibitory agent, whereas fluoride (F-) is the only truly accepted anticaries agent available at present. As they have discrete mechanisms of action, a combination effect of these agents on human dental caries m

  15. The passive control of air pollution exposure in Dublin, Ireland: a combined measurement and modelling case study.

    Science.gov (United States)

    Gallagher, J; Gill, L W; McNabola, A

    2013-08-01

    This study investigates the potential real world application of passive control systems to reduce personal pollutant exposure in an urban street canyon in Dublin, Ireland. The implementation of parked cars and/or low boundary walls as a passive control system has been shown to minimise personal exposure to pollutants on footpaths in previous investigations. However, previous research has been limited to generic numerical modelling studies. This study combines real-time traffic data, meteorological conditions and pollution concentrations, in a real world urban street canyon before and after the implementation of a passive control system. Using a combination of field measurements and numerical modelling this study assessed the potential impact of passive controls on personal exposure to nitric oxide (NO) concentrations in the street canyon in winter conditions. A calibrated numerical model of the urban street canyon was developed, taking into account the variability in traffic and meteorological conditions. The modelling system combined the computational fluid dynamic (CFD) simulations and a semi-empirical equation, and demonstrated a good agreement with measured field data collected in the street canyon. The results indicated that lane distribution, fleet composition and vehicular turbulence all affected pollutant dispersion, in addition to the canyon geometry and local meteorological conditions. The introduction of passive controls displayed mixed results for improvements in air quality on the footpaths for different wind and traffic conditions. Parked cars demonstrated the most comprehensive passive control system with average improvements in air quality of up to 15% on the footpaths. This study highlights the potential of passive controls in a real street canyon to increase dispersion and improve air quality at street level.

  16. Comparative Study of Fatigue Damage Models Using Different Number of Classes Combined with the Rainflow Method

    Directory of Open Access Journals (Sweden)

    S. Zengah

    2013-06-01

    Full Text Available Fatigue damage increases with applied load cycles in a cumulative manner. Fatigue damage models play a key role in life prediction of components and structures subjected to random loading. The aim of this paper is the examination of the performance of the “Damaged Stress Model”, proposed and validated, against other fatigue models under random loading before and after reconstruction of the load histories. To achieve this objective, some linear and nonlinear models proposed for fatigue life estimation and a batch of specimens made of 6082T6 aluminum alloy is subjected to random loading. The damage was cumulated by Miner’s rule, Damaged Stress Model (DSM, Henry model and Unified Theory (UT and random cycles were counted with a rain-flow algorithm. Experimental data on high-cycle fatigue by complex loading histories with different mean and amplitude stress values are analyzed for life calculation and model predictions are compared.

  17. A Study of Simulation Effectiveness in Modeling Heavy Combined Arms Combat in Urban Environments

    Science.gov (United States)

    2007-05-01

    appearance of reality (the suspension of disbelief ) equals reality for training effect. 8. Treatment of Vehicles and Aircraft 1. Hulks (Creation...small units, the suspension of disbelief presented by the models in OFP/VBS1 works as effectively as the more precise models presented by JCATS

  18. Surface circulation at the Strait of Gibraltar: A combined HF radar and high resolution model study

    Science.gov (United States)

    Soto-Navarro, Javier; Lorente, Pablo; Álvarez Fanjul, Enrique; Carlos Sánchez-Garrido, Jose; García-Lafuente, Jesús

    2016-03-01

    Observations from a high frequency radar system and outputs from a high resolution operational ocean model working at the Strait of Gibraltar have been analyzed and compared during the period February 2013 to September 2014 in order to evaluate their capability to resolve the surface circulation of the region. The description of the mean circulation patterns has been statistically assessed, showing good agreement, particularly in the central region of the strait corresponding with the Atlantic Jet (AJ) stream, although some short scale features are not reproduced by the model. In the frequency domain very high concordance is observed. Tidal maps of diurnal and semidiurnal constituents are in good agreement with previous observations. The analysis of the model and radar response to the wind forcing reveals that the low resolution of the model wind-forcing field and its deeper superficial level smoothes the wind effect on the simulated currents. The first three EOF modes account for the 86% of model and radar variances. The coincidence between the observed and simulated patterns is very significant for the first two modes, which account for the mean velocity field and the latitudinal shifting of the AJ consequence of the flow-topography interaction. The third mode captures the wind-induced circulation, and greater discrepancies are found in this case. Results underline the complementary character of both systems: radar observations improve the model description, resolving short scale processes, while the model completes the radar information when the time or spatial coverage is poorer.

  19. Combining dendrochronology and matrix modelling in demographic studies: An evaluation for Juniperus procera in Ethiopia

    NARCIS (Netherlands)

    Couralet, C.; Sass, U.G.W.; Sterck, F.J.; Zuidema, P.A.

    2005-01-01

    Tree demography was analysed by applying dendrochronological techniques and matrix modelling on a static data set of Juniperus procera populations of Ethiopian dry highland forests. Six permanent sample plots were established for an inventory of diameters and 11 stem discs were collected for

  20. Trivacancy in silicon: A combined DLTS and ab-initio modeling study

    Science.gov (United States)

    Markevich, V. P.; Peaker, A. R.; Lastovskii, S. B.; Murin, L. I.; Coutinho, J.; Markevich, A. V.; Torres, V. J. B.; Briddon, P. R.; Dobaczewski, L.; Monakhov, E. V.; Svensson, B. G.

    2009-12-01

    Deep level transient spectroscopy and ab-initio modeling have been used for identification of energy levels and structure of trivacancy (V3) in Si. It is found that in the neutral charge state the V3 is bistable, with the "fourfold" configuration being lower in energy than the (1 1 0) planar configuration. V3 in the (1 1 0) planar configuration gives rise to two acceptor levels at Ec-0.36 eV and Ec-0.46 eV in the gap, while in the "fourfold" configuration the defect has trigonal symmetry and an acceptor level at Ec-0.075 eV.

  1. Phyloclimatic modeling: combining phylogenetics and bioclimatic modeling.

    Science.gov (United States)

    Yesson, C; Culham, A

    2006-10-01

    We investigate the impact of past climates on plant diversification by tracking the "footprint" of climate change on a phylogenetic tree. Diversity within the cosmopolitan carnivorous plant genus Drosera (Droseraceae) is focused within Mediterranean climate regions. We explore whether this diversity is temporally linked to Mediterranean-type climatic shifts of the mid-Miocene and whether climate preferences are conservative over phylogenetic timescales. Phyloclimatic modeling combines environmental niche (bioclimatic) modeling with phylogenetics in order to study evolutionary patterns in relation to climate change. We present the largest and most complete such example to date using Drosera. The bioclimatic models of extant species demonstrate clear phylogenetic patterns; this is particularly evident for the tuberous sundews from southwestern Australia (subgenus Ergaleium). We employ a method for establishing confidence intervals of node ages on a phylogeny using replicates from a Bayesian phylogenetic analysis. This chronogram shows that many clades, including subgenus Ergaleium and section Bryastrum, diversified during the establishment of the Mediterranean-type climate. Ancestral reconstructions of bioclimatic models demonstrate a pattern of preference for this climate type within these groups. Ancestral bioclimatic models are projected into palaeo-climate reconstructions for the time periods indicated by the chronogram. We present two such examples that each generate plausible estimates of ancestral lineage distribution, which are similar to their current distributions. This is the first study to attempt bioclimatic projections on evolutionary time scales. The sundews appear to have diversified in response to local climate development. Some groups are specialized for Mediterranean climates, others show wide-ranging generalism. This demonstrates that Phyloclimatic modeling could be repeated for other plant groups and is fundamental to the understanding of

  2. Combined Pharmacophore Modeling, 3D-QSAR, Homology Modeling and Docking Studies on CYP11B1 Inhibitors

    Directory of Open Access Journals (Sweden)

    Rui Yu

    2015-01-01

    Full Text Available The mitochondrial cytochrome P450 enzymes inhibitor steroid 11β-hydroxylase (CYP11B1 can decrease the production of cortisol. Therefore, these inhibitors have an effect in the treatment of Cushing’s syndrome. A pharmacophore model generated by Genetic Algorithm with Linear Assignment for Hypermolecular Alignment of Datasets (GALAHAD was used to align the compounds and perform comparative molecular field analysis (CoMFA with Q2 = 0.658, R2 = 0.959. The pharmacophore model contained six hydrophobic regions and one acceptor atom, and electropositive and bulky substituents would be tolerated at the A and B sites, respectively. A three-dimensional quantitative structure-activity relationship (3D-QSAR study based on the alignment with the atom root mean square (RMS was applied using comparative molecular field analysis (CoMFA with Q2 = 0.666, R2 = 0.978, and comparative molecular similarity indices analysis (CoMSIA with Q2 = 0.721, R2 = 0.972. These results proved that all the models have good predictability of the bioactivities of inhibitors. Furthermore, the QSAR models indicated that a hydrogen bond acceptor substituent would be disfavored at the A and B groups, while hydrophobic groups would be favored at the B site. The three-dimensional (3D model of the CYP11B1 was generated based on the crystal structure of the CYP11B2 (PDB code 4DVQ. In order to probe the ligand-binding modes, Surflex-dock was employed to dock CYP11B1 inhibitory compounds into the active site of the receptor. The docking result showed that the imidazolidine ring of CYP11B1 inhibitors form H bonds with the amino group of residue Arg155 and Arg519, which suggested that an electronegative substituent at these positions could enhance the activities of compounds. All the models generated by GALAHAD QSAR and Docking methods provide guidance about how to design novel and potential drugs for Cushing’s syndrome treatment.

  3. Trivacancy in silicon: A combined DLTS and ab-initio modeling study

    Energy Technology Data Exchange (ETDEWEB)

    Markevich, V.P., E-mail: V.Markevich@manchester.ac.u [University of Manchester, Manchester M60 1QD (United Kingdom); Peaker, A.R. [University of Manchester, Manchester M60 1QD (United Kingdom); Lastovskii, S.B.; Murin, L.I. [Scientific-Practical Materials Research Center of NAS of Belarus, Minsk 220072 (Belarus); Coutinho, J.; Markevich, A.V.; Torres, V.J.B. [Department of Physics and I3N, University of Aveiro, 3810-193 Aveiro (Portugal); Briddon, P.R. [University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU (United Kingdom); Dobaczewski, L. [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw (Poland); Monakhov, E.V.; Svensson, B.G. [Department of Physics, Oslo University, 0316 Oslo (Norway)

    2009-12-15

    Deep level transient spectroscopy and ab-initio modeling have been used for identification of energy levels and structure of trivacancy (V{sub 3}) in Si. It is found that in the neutral charge state the V{sub 3} is bistable, with the 'fourfold' configuration being lower in energy than the (1 1 0) planar configuration. V{sub 3} in the (1 1 0) planar configuration gives rise to two acceptor levels at E{sub c}-0.36 eV and E{sub c}-0.46 eV in the gap, while in the 'fourfold' configuration the defect has trigonal symmetry and an acceptor level at E{sub c}-0.075 eV.

  4. Nitrogen Management Evaluated by Models Combined with GIS-A Case Study of Jiangsu Croplands, China, in 2000

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The objective of this study is to provide scientific guidance for optimizing agricultural field nitrogen management that is based on the evaluation of current nitrogen application practice in Jiangsu Province, China, in 2000. The agricultural nitrogen models, consist of the soil mineralization model, the organic manure nitrogen releasing model, and the nitrogenous fertilizer use efficiency model. These models combined with the geographic information system technique were used to describe the spatial variability of nitrogen released from soil and organic manure and to identify its contributing factors. The comparison of the nitrogen fertilizer amount required by croplands, which was simulated by the models with the actual nitrogen fertilizer applied rate, was used to evaluate the current nitrogen application. The results showed that nitrogen was excessively applied in 71.8% croplands, given that the actual crop yield was desired. The excessive nitrogen amounted to 760 kiloton, accounting for 41.5% of the total nitrogen applied. Given that the actual highest yield was desired, nitrogen was reduced in 64.3% croplands. The total shortage of nitrogen was about 800 kiloton. Low use efficiency of nitrogen fertilizer was found in Taihu Lake area, Nanjing-Zhenjiang hilly area, and Xuzhou area, whereas the east beach area of Jiangsu showed an obvious deficiency of nitrogen fertilizer inputs. A balance of nitrogen fertilizer in Jiangsu croplands between excessive and deficient application areas would greatly benefit economic and environmental advantages.

  5. A combined disease management and process modeling approach for assessing and improving care processes: a fall management case-study.

    Science.gov (United States)

    Askari, Marjan; Westerhof, Richard; Eslami, Saied; Medlock, Stephanie; de Rooij, Sophia E; Abu-Hanna, Ameen

    2013-10-01

    To propose a combined disease management and process modeling approach for evaluating and improving care processes, and demonstrate its usability and usefulness in a real-world fall management case study. We identified essential disease management related concepts and mapped them into explicit questions meant to expose areas for improvement in the respective care processes. We applied the disease management oriented questions to a process model of a comprehensive real world fall prevention and treatment program covering primary and secondary care. We relied on interviews and observations to complete the process models, which were captured in UML activity diagrams. A preliminary evaluation of the usability of our approach by gauging the experience of the modeler and an external validator was conducted, and the usefulness of the method was evaluated by gathering feedback from stakeholders at an invitational conference of 75 attendees. The process model of the fall management program was organized around the clinical tasks of case finding, risk profiling, decision making, coordination and interventions. Applying the disease management questions to the process models exposed weaknesses in the process including: absence of program ownership, under-detection of falls in primary care, and lack of efficient communication among stakeholders due to missing awareness about other stakeholders' workflow. The modelers experienced the approach as usable and the attendees of the invitational conference found the analysis results to be valid. The proposed disease management view of process modeling was usable and useful for systematically identifying areas of improvement in a fall management program. Although specifically applied to fall management, we believe our case study is characteristic of various disease management settings, suggesting the wider applicability of the approach. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. Bioremediation in marine ecosystems: a computational study combining ecological modelling and flux balance analysis

    OpenAIRE

    Marianna eTaffi; Nicola ePaoletti; Claudio eAngione; Sandra ePucciarelli; Mauro eMarini; Pietro eLio

    2014-01-01

    The pressure to search effective bioremediation methodologies for contaminated ecosystems has led to the large-scale identification of microbial species and metabolic degradation pathways. However, minor attention has been paid to the study of bioremediation in marine food webs and to the definition of integrated strategies for reducing bioaccumulation in species. We propose a novel computational framework for analysing the multiscale effects of bioremediation at the ecosystem level, based o...

  7. Bioremediation in marine ecosystems: a computational study combining ecological modeling and flux balance analysis

    OpenAIRE

    Taffi, Marianna; Paoletti, Nicola; Angione, Claudio; Pucciarelli, Sandra; Marini, Mauro; Liò, Pietro

    2014-01-01

    The pressure to search effective bioremediation methodologies for contaminated ecosystems has led to the large-scale identification of microbial species and metabolic degradation pathways. However, minor attention has been paid to the study of bioremediation in marine food webs and to the definition of integrated strategies for reducing bioaccumulation in species. We propose a novel computational framework for analysing the multiscale effects of bioremediation at the ecosystem level, based on...

  8. Headbobber: a combined morphogenetic and cochleosaccular mouse model to study 10qter deletions in human deafness.

    Science.gov (United States)

    Buniello, Annalisa; Hardisty-Hughes, Rachel E; Pass, Johanna C; Bober, Eva; Smith, Richard J; Steel, Karen P

    2013-01-01

    The recessive mouse mutant headbobber (hb) displays the characteristic behavioural traits associated with vestibular defects including headbobbing, circling and deafness. This mutation was caused by the insertion of a transgene into distal chromosome 7 affecting expression of native genes. We show that the inner ear of hb/hb mutants lacks semicircular canals and cristae, and the saccule and utricle are fused together in a single utriculosaccular sac. Moreover, we detect severe abnormalities of the cochlear sensory hair cells, the stria vascularis looks severely disorganised, Reissner's membrane is collapsed and no endocochlear potential is detected. Myo7a and Kcnj10 expression analysis show a lack of the melanocyte-like intermediate cells in hb/hb stria vascularis, which can explain the absence of endocochlear potential. We use Trp2 as a marker of melanoblasts migrating from the neural crest at E12.5 and show that they do not interdigitate into the developing strial epithelium, associated with abnormal persistence of the basal lamina in the hb/hb cochlea. We perform array CGH, deep sequencing as well as an extensive expression analysis of candidate genes in the headbobber region of hb/hb and littermate controls, and conclude that the headbobber phenotype is caused by: 1) effect of a 648 kb deletion on distal Chr7, resulting in the loss of three protein coding genes (Gpr26, Cpmx2 and Chst15) with expression in the inner ear but unknown function; and 2) indirect, long range effect of the deletion on the expression of neighboring genes on Chr7, associated with downregulation of Hmx3, Hmx2 and Nkx1.2 homeobox transcription factors. Interestingly, deletions of the orthologous region in humans, affecting the same genes, have been reported in nineteen patients with common features including sensorineural hearing loss and vestibular problems. Therefore, we propose that headbobber is a useful model to gain insight into the mechanisms underlying deafness in human 10qter

  9. Study of the leaching behaviour of ladle slags by means of leaching tests combined with geochemical modelling and mineralogical investigations.

    Science.gov (United States)

    Loncnar, Mojca; van der Sloot, Hans A; Mladenovič, Ana; Zupančič, Marija; Kobal, Lara; Bukovec, Peter

    2016-11-05

    In this study, the leachability of freshly produced ladle slag derived from both austenitic and ferritic stainless steel production, and from electrical and structural steel production, was investigated, in order to determine whether variations in the chemical and mineralogical composition of these slags affect their leaching behaviour. The effect of the method used for slag cooling was also studied. The results obtained by using the single batch test were combined with those obtained by means of more sophisticated characterisation leaching tests, which, in combination with geochemical speciation modelling, helped to better identify the release mechanisms and phases that control the release of individual elements. It was found that, although variations in the chemical composition of the slag can affect the slag's minerology, neither such variations, nor the choice of the slag cooling treatment, have a significant effect on the leachability of individual elements, since the leaching is governed by surface phenomena. In fact, the mineral transformations on the slag surface, rather than the bulk mineral composition, dictate the release of these elements from the ladle slag. The solubility-controlling phases were predicted by multi-element modelling, and verified to the extent made possible by the performed mineralogical investigations.

  10. Study of radon dispersion in typical dwelling using CFD modeling combined with passive-active measurements

    Science.gov (United States)

    Rabi, R.; Oufni, L.

    2017-10-01

    Inhalation of radon (222Rn) and its decay products are a major source of natural radiation exposure. It is known from recent surveys in many countries that radon and its progeny contribute significantly to total inhalation dose and it is fairly established that radon when inhaled in large quantity causes lung disorder. Indoor air conditions and ventilation systems strongly influence the indoor radon concentration. This study focuses on investigating both numerically and experimentally the influence of environmental conditions on the indoor radon concentration and spatial distribution. The numerical results showed that ventilation rate, temperature and humidity have significant impacts on both radon content and distribution. The variations of radon concentration with the ventilation, temperature and relative humidity are discussed. The measurement results show the diurnal variations of the indoor radon concentration are found to exhibit a positive correlation with relative humidity and negatively correlate with the air temperature. The analytic solution is used to validate the numeric results. The comparison amongst analytical, numerical and measurement results shows close agreement.

  11. Transarterial chemoembolization alone and in combination with other therapies: a comparative study in an animal HCC model

    Energy Technology Data Exchange (ETDEWEB)

    Maataoui, A.; Qian, J.; Vossoughi, D.; Khan, M.F.; Vogl, T.J. [Johann Wolfgang Goethe University, Institute for Diagnostic and Interventional Radiology, Frankfurt/Main (Germany); Oppermann, E.; Bechstein, W.O. [Johann Wolfgang Goethe University, Department of Visceral Surgery, Frankfurt/Main (Germany)

    2005-01-01

    The purpose of this study is to compare transarterial chemoembolization (TACE) alone and in combination with other therapies in an animal model. Subcapsular implantation of a solid Morris hepatoma 3924A in the liver was carried out in 50 male ACI rats (day 0). Tumor volume (V1) was measured by MRI (day 13). After laparotomy and retrograde placement of a catheter into the gastroduodenal artery (day 14), the following protocols of the interventional procedure were applied: TACE (mitomycin C + lipiodol) + immunotherapy (group A: TNF{alpha} + IL-2, group B: OK-432 + IL-2); TACE + antiangiogenesis therapy (group C: TNP-470, group D: endostatin); TACE alone in group E (control group). Tumor volume (V2) was assessed by MRI and the mean ratio of x(V2/V1) was calculated. Data were analyzed using Dunnett's ttest (comparing therapeutic groups with the control group) and the Student-Newman-Keuls test (comparing significant therapeutic groups). Multivariate analysis showed a significant reduction in the tumor growth rate (P<0.05) in groups B (x=6.53) and C (x=4.01) compared to the mean ratio of the control group E (x=9.14). Significant results were observed in group C (P<0.05) in comparison with the other therapeutic groups. TACE combined with immunotherapy (OK-432) and antiangiogenesis therapy (TNP-470) retards tumor growth compared with TACE alone in an HCC animal model. (orig.)

  12. Study of the machining process of nano-electrical discharge machining based on combined atomistic-continuum modeling method

    Science.gov (United States)

    Zhang, Guojun; Guo, Jianwen; Ming, Wuyi; Huang, Yu; Shao, Xinyu; Zhang, Zhen

    2014-01-01

    Nano-electrical discharge machining (nano-EDM) is an attractive measure to manufacture parts with nanoscale precision, however, due to the incompleteness of its theories, the development of more advanced nano-EDM technology is impeded. In this paper, a computational simulation model combining the molecular dynamics simulation model and the two-temperature model for single discharge process in nano-EDM is constructed to study the machining mechanism of nano-EDM from the thermal point of view. The melting process is analyzed. Before the heated material gets melted, thermal compressive stress higher than 3 GPa is induced. After the material gets melted, the compressive stress gets relieved. The cooling and solidifying processes are also analyzed. It is found that during the cooling process of the melted material, tensile stress higher than 3 GPa arises, which leads to the disintegration of material. The formation of the white layer is attributed to the homogeneous solidification, and additionally, the resultant residual stress is analyzed.

  13. Antitumor efficacy of combination of interferon-gamma-inducible protein 10 gene with gemcitabine, a study in murine model

    Directory of Open Access Journals (Sweden)

    Zhang Zhixuan

    2008-11-01

    Full Text Available Abstract Background Interferon-γ-inducible protein 10 (IP-10 is a potent inhibitor of tumor angiogenesis. It has been reported that the antiangiogenic therapy combined with chemotherapy has synergistic effects. Methods To elucidate the mechanisms of IP-10 gene combined with a chemotherapy agent, we intramuscularly injected pBLAST-IP-10 expression plasmid combined with gemcitabine into tumor-bearing mice. Results The proliferation of endothelial cells was effectively inhibited by IP-10 combined with gemcitabine in vitro. Treatment with pBLAST-IP-10 twice a week for 4 weeks combined with gemcitabine 10 mg/kg (once a week resulted in sustained high level of IP-10 protein in serum, inhibition of tumor growth and prolongation of the survival of tumor-bearing mice. Compared with administration of IP-10 plasmid or gemcitabine alone, the angiogenesis in tumors were apparently inhibited, and the numbers of apoptotic cells and lymphocytes in tumor increased in the combination therapy group. Conclusion Our data indicate that the gene therapy of antiangiogenesis by intramuscular delivery of plasmid DNA encoding IP-10 combined with gemcitabine has synergistic effects on tomor by inhibiting the proliferation of endothelail cells, inducing the apoptosis of tumor cells, and recruiting lymphocytes to tumor in murine models. The present findings provided evidence of antitumor effects of genetherapy combined with chemotherapy.

  14. Lymph node histopathological studies in a combined adjuvant–collagen induced arthritis model in albino rat Rattus rattus

    Directory of Open Access Journals (Sweden)

    Ahmed S. Ibraheem

    2013-08-01

    Full Text Available There are at least 16 types of collagen. Antibodies, to collagens, in particular to types I and II have been reported in a number of autoimmune diseases. In this study, we used rat and bovine collagens to study the effects of anti-collagen antibodies on the lymphoid organs of rats Histological examination of the lymph node sections showed that immunization with different collagen types combined with the adjuvant used in this study induced arthritis and immune reaction in lymph nodes. The degrees of the disease symptoms and immune reaction depended on the foreignness of the stimulating collagen and on whether it was accompanied with adjuvant. Anti-collagen antibodies led to a decrease in the thickness of the lymph node cortex and atrophy, with medullary hyperplasia, small granulomas appeared in the section. Immunizing with either bovine collagen or BSA has shown a remarkable distortion in architecture appeared, follicular hyperplasia and reactive inflammatory hyperplasia of the LN. Passive transfer of rat anti-rat collagen antibodies either accompanied with Freund’s adjuvant or not with a lesser degree of severity, resulted in epithelioid cells forming granuloma surrounded by collar of lymphocytes, scattered apoptotic bodies, lymphatic sinus ectasia accompanied with lymphoid follicles atrophy. The results of our study present a reliable model for collagen induced arthritis which is suitable for the investigation of the mechanism of disease induction and treatment approaches.

  15. Combining Q2MM Modeling and Kinetic Studies for Refinement of the Osmium-catalyzed Asymmetric Dihydroxylation (AD) Mnemonic

    DEFF Research Database (Denmark)

    Fristrup, Peter; Jensen, Gitte Holm; Andersen, Marie Louise Nygaard

    2006-01-01

    The interactions between the substrate and the ligand in the Sharpless AD reaction have been examined in detail, using a combination of substrate competition experiments and molecular modeling of transition states. There is a good agreement between computational and experimental results, in parti...

  16. Heterogeneous reactions of NO2 and HNO3 on oxides and mineral dust: A combined laboratory and modeling study

    Science.gov (United States)

    Underwood, G. M.; Song, C. H.; Phadnis, M.; Carmichael, G. R.; Grassian, V. H.

    2001-08-01

    This study combines laboratory measurements and modeling analysis to quantify the role of heterogeneous reactions of gaseous nitrogen dioxide and nitric acid on mineral oxide and mineral dust particles in tropospheric ozone formation. At least two types of heterogeneous reactions occur on the surface of these particles. Upon initial exposure of the oxide to NO2 there is a loss of NO2 from the gas phase by adsorption on the particle surface, i.e., NO2(g) → NO2(a). As the reaction proceeds, a reduction of gaseous NO2 to NO, NO2 (g) → NO (g) is found to occur. Initial uptake coefficients γ0 for NO2 on the surface of these particles have been measured at 298 K using a Knudsen cell reactor coupled to a mass spectrometer. For the oxides studied, α,γ-Al2O3, α,γ-Fe2O3, TiO2, SiO2, CaO, and MgO, γ0 ranges from dry surfaces are just below the lower limit to have an impact on the photochemical oxidant cycle, while the heterogeneous reactivity of HNO3 is sufficiently large to have an effect. Under conditions of high mineral dust mass loadings and/or smaller size distributions the importance of these reactions (both NO2 and HNO3) is expected to increase.

  17. Pulmonary functional MRI:an animal model study of oxygen-enhanced ventilation combined with Gd-DTPA-enhanced perfusion

    Institute of Scientific and Technical Information of China (English)

    杨健; 万明习; 郭佑民

    2004-01-01

    Background The assessment of regional pulmonary ventilation and perfusion is essential for the evaluation of a variety of lung disorders. Pulmonary ventilation MRI using inhaled oxygen as a contrast medium can be obtained with a clinical MR scanner, without additional equipment, and has been demonstrated to be a feasible means of assessing ventilation in animal models and some clinical patients. However, few studies have reported on MR ventilation-perfusion imaging. In this study, we evaluated the usefulness of oxygen-enhanced ventilation in combination with first-pass Gd-DTPA-enhanced perfusion MRI in a canine model of pulmonary embolism and airway obstruction.Methods Peripheral pulmonary embolisms were produced in eight dogs by intravenous injection of gelfoam strips at the pulmonary segmental arterial level, and airway obstructions were created in five of the dogs by inserting a self-designed balloon catheter into a secondary bronchus. Oxygen-enhanced MR ventilation images were produced by subtracting images from before and after inhalation of pure oxygen. Pulmonary perfusion MR images were acquired with a dynamic three-dimensional fast gradient-echo sequence. MR ventilation and perfusion images were read and contrasted with results from general examinations of pathological anatomy, ventilation-perfusion scintigraphy, and pulmonary angiography. Results Regions identified as having airway obstructions matched using both MR ventilation and perfusion imaging, but regions of pulmonary embolisms were mismatched. The area of airway obstruction defects was smaller using MR ventilation imagery than that using ventilation scintigraphy. Abnormal perfusion regions due to pulmonary embolisms were divided into defective regions and reduced regions based on the time course of signal intensity changes. In the diagnosis of pulmonary embolisms with the technique of ventilation and perfusion MRI, sensitivity and specificity were 75.0% and 98.1%, respectively, and the diagnostic

  18. A Combined Observational and Modeling Approach to Study Modern Dust Transport from the Patagonia Desert to East Antarctica

    Science.gov (United States)

    Gasso, S.; Stein, A.; Marino, F.; Castellano, E.; Udisti, R.; Ceratto, J.

    2010-01-01

    The understanding of present atmospheric transport processes from Southern Hemisphere (SH) landmasses to Antarctica can improve the interpretation of stratigraphic data in Antarctic ice cores. In addition, long range transport can deliver key nutrients normally not available to marine ecosystems in the Southern Ocean and may trigger or enhance primary productivity. However, there is a dearth of observational based studies of dust transport in the SH. This work aims to improve current understanding of dust transport in the SH by showing a characterization of two dust events originating in the Patagonia desert (south end of South America). The approach is based on a combined and complementary use of satellite retrievals (detectors MISR, MODIS, GLAS ,POLDER, OMI,), transport model simulation (HYSPLIT) and surface observations near the sources and aerosol measurements in Antarctica (Neumayer and Concordia sites). Satellite imagery and visibility observations confirm dust emission in a stretch of dry lakes along the coast of the Tierra del Fuego (TdF) island (approx.54deg S) and from the shores of the Colihue Huapi lake in Central Patagonia (approx.46deg S) in February 2005. Model simulations initialized by these observations reproduce the timing of an observed increase in dust concentration at the Concordia Station and some of the observed increases in atmospheric aerosol absorption (here used as a dust proxy) in the Neumayer station. The TdF sources were the largest contributors of dust at both sites. The transit times from TdF to the Neumayer and Concordia sites are 6-7 and 9-10 days respectively. Lidar observations and model outputs coincide in placing most of the dust cloud in the boundary layer and suggest significant de- position over the ocean immediately downwind. Boundary layer dust was detected as far as 1800 km from the source and approx.800 km north of the South Georgia Island over the central sub-Antarctic Atlantic Ocean. Although the analysis suggests the

  19. Study of Combination Forecasting in Airline Traffic Turnover

    Institute of Scientific and Technical Information of China (English)

    LIU Jun; QIU Wan-hua; WEI Cun-ping

    2001-01-01

    The basic theory and method of the combination forecasting are introduced. Based on the actual data in an airline, the case study was presented. In the case study, two basic forecasting models are set up,which are the time-regression plus seasonal factor model and the logarithm additive Winters model. And two combination models are established with the basic models, which are the optimal combination model and the regressive combination model. The results of the study are guidable to the practice.

  20. [A study of combination treatment with nacom (levodopa + carbodope) and citicoline in the model of Parkinson disease in rats].

    Science.gov (United States)

    Kashkin, V A; Shekunova, E V; Makarova, M N; Makarov, V G

    2017-01-01

    To evaluate the efficacy of the combined use of citicoline (neipilept) and levodopa/carbidopa (nakom) in the rotenone model of Parkinson's disease in rats. Rotenone was administrated during 14 days in dose 2 mg/kg/day subcutaneously. The duration of treatment was 7 days, intragastrically. Alteration of locomotor behavior components, muscular rigidity in resistance to passive flexion in the ankle joint and signs of extrapyramidal disorders were assessed. Combined therapy led to the decrease in muscle rigidity (the decrease of gibbosity in resistance to passive flexion in the ankle joint). There was a decrease in oligokinesia that emerged in higher vertical and horizontal locomotor activity of experimental animals, decrease in the time of head turning during climbing down the pole and total time of climbing down the pole. The combination of drugs had a more pronounced therapeutic effect on extrapyramidal disorders compared to monotherapy.

  1. A Test of the Combined Effects Model.

    Science.gov (United States)

    Kimsey, William D.; And Others

    Two waves of telephone interviews with a sample of 141 voters were used in a study of political communication effects during the 1974 congressional election in the Illinois 24th Congressional District. Seven variables specified by the combined-effects model were derived from the interviews and factor analyzed. Two factors were found and…

  2. Passive urban ventilation by combined buoyancy-driven slope flow and wall flow: Parametric CFD studies on idealized city models

    Science.gov (United States)

    Luo, Zhiwen; Li, Yuguo

    2011-10-01

    This paper reports the results of a parametric CFD study on idealized city models to investigate the potential of slope flow in ventilating a city located in a mountainous region when the background synoptic wind is absent. Examples of such a city include Tokyo in Japan, Los Angeles and Phoenix in the US, and Hong Kong. Two types of buoyancy-driven flow are considered, i.e., slope flow from the mountain slope (katabatic wind at night and anabatic wind in the daytime), and wall flow due to heated/cooled urban surfaces. The combined buoyancy-driven flow system can serve the purpose of dispersing the accumulated urban air pollutants when the background wind is weak or absent. The microscopic picture of ventilation performance within the urban structures was evaluated in terms of air change rate (ACH) and age of air. The simulation results reveal that the slope flow plays an important role in ventilating the urban area, especially in calm conditions. Katabatic flow at night is conducive to mitigating the nocturnal urban heat island. In the present parametric study, the mountain slope angle and mountain height are assumed to be constant, and the changing variables are heating/cooling intensity and building height. For a typical mountain of 500 m inclined at an angle of 20° to the horizontal level, the interactive structure is very much dependent on the ratio of heating/cooling intensity as well as building height. When the building is lower than 60 m, the slope wind dominates. When the building is as high as 100 m, the contribution from the urban wall flow cannot be ignored. It is found that katabatic wind can be very beneficial to the thermal environment as well as air quality at the pedestrian level. The air change rate for the pedestrian volume can be as high as 300 ACH.

  3. A Novel Combined Model Based on an Artificial Intelligence Algorithm—A Case Study on Wind Speed Forecasting in Penglai, China

    Directory of Open Access Journals (Sweden)

    Feiyu Zhang

    2016-06-01

    Full Text Available Wind speed forecasting plays a key role in wind-related engineering studies and is important in the management of wind farms. Current forecasting models based on different optimization algorithms can be adapted to various wind speed time series data. However, these methodologies cannot aggregate different hybrid forecasting methods and take advantage of the component models. To avoid these limitations, we propose a novel combined forecasting model called SSA-PSO-DWCM, i.e., particle swarm optimization (PSO determined weight coefficients model. This model consisted of three main steps: one is the decomposition of the original wind speed signals to discard the noise, the second is the parameter optimization of the forecasting method, and the last is the combination of different models in a nonlinear way. The proposed combined model is examined by forecasting the wind speed (10-min intervals of wind turbine 5 located in the Penglai region of China. The simulations reveal that the proposed combined model demonstrates a more reliable forecast than the component forecasting engines and the traditional combined method, which is based on a linear method.

  4. Psychosocial Work Environment and Myocardial Infarction: Improving Risk Estimation by Combining Two Complementary Job Stress Models in the SHEEP Study

    National Research Council Canada - National Science Library

    R. Peter; J. Siegrist; J. Hallqvist; C. Reuterwall; T. Theorell; The SHEEP Study Group

    2002-01-01

    Objectives: Associations between two alternative formulations of job stress derived from the effort-reward imbalance and the job strain model and first non-fatal acute myocardial infarction were studied...

  5. The study of biological effects of electromagnetic mobile phone radiation on experimental animals by combining numerical modeling and experimental research

    Directory of Open Access Journals (Sweden)

    Dejan Krstić

    2012-12-01

    Full Text Available In order to study biological effects of electromagneticradiation, it is essential to know the real values of field componentsthat penetrated the tissue. The study of biological effects is usuallyperformed on experimental animals. The biological effects observedon experimental animals should be linked with penetrating field inthe tissue. The penetrating electromagnetic field is almost impossibleto measure; therefore, modeling process must be carried out and thefield components in models of experimental animals could becalculated. This paper presents an approach to modeling of fieldpenetration and gives contribution to understanding the real effects of the fields and the sensitivity of tissues to electromagnetic radiation generated by mobile phone.

  6. Studying non-linearity of Mercury magnetosphere and solar wind interaction features using the combined hybrid model

    Science.gov (United States)

    Parunakian, David; Dyadechkin, Sergey; Alexeev, Igor; Belenkaya, Elena; Khodachenko, Maxim; Kallio, Esa; Alho, Markku

    2017-04-01

    The main focus of this work is to investigate non-linearity of Mercury's magnetospheric features. We use the paraboloid magnetospheric model (PMM) to calculate the initial magnetospheric field which we then use in hybrid simulations. We show that the initial total magnetospheric field can be considered a linear combination of the planetary dipole field, magnetospheric current system fields, and a penetrating portion of the interplanetary magnetic field (IMF). We use two sets of modelling runs with IMF values of identical magnitudes and anti-parallel directions. We then compute semi-sums and semi-differences of final magnetic field maps generated by hybrid plasma simulations, and use semi-sums to cancel out IMF contributions and semi-differences to cancel out PMM contributions. The remnant fields outside and inside the magnetosphere (for semi-sum and semi-difference fields, accordingly) are used to improve our ability to determine the position of the bow shock and magnetopause, as well as calculate the IMF penetration coefficient that results into best matches of this model to observational MESSENGER data. We compare Mercury's magnetosheath magnetic field predicted by our model with MESSENGER data in the appropriate orbit sections.

  7. Study of the validity of a combined potential model using the Hybrid Reverse Monte Carlo method in Fluoride glass system

    Directory of Open Access Journals (Sweden)

    M. Kotbi

    2013-03-01

    Full Text Available The choice of appropriate interaction models is among the major disadvantages of conventional methods such as Molecular Dynamics (MD and Monte Carlo (MC simulations. On the other hand, the so-called Reverse Monte Carlo (RMC method, based on experimental data, can be applied without any interatomic and/or intermolecular interactions. The RMC results are accompanied by artificial satellite peaks. To remedy this problem, we use an extension of the RMC algorithm, which introduces an energy penalty term into the acceptance criteria. This method is referred to as the Hybrid Reverse Monte Carlo (HRMC method. The idea of this paper is to test the validity of a combined potential model of coulomb and Lennard-Jones in a Fluoride glass system BaMnMF7 (M = Fe,V using HRMC method. The results show a good agreement between experimental and calculated characteristics, as well as a meaningful improvement in partial pair distribution functions (PDFs. We suggest that this model should be used in calculating the structural properties and in describing the average correlations between components of fluoride glass or a similar system. We also suggest that HRMC could be useful as a tool for testing the interaction potential models, as well as for conventional applications.

  8. Combined fertility and embryotoxicity study.

    Science.gov (United States)

    Reynaud, Lucie; Marsden, Edward

    2013-01-01

    Under normal circumstances, fertility and embryotoxicity studies are run separately according to the ICH S5(R2) guideline for the detection of toxicity to reproduction of medicinal products (1). However, the flexible approach of the S5(R2) guideline also allows the reproduction stages covered in the fertility and embryo-fetal development studies (stages A to D) to be combined into a single study design. The administration period covers the pre-mating and gestation phases through to closure of the hard palate. The principal advantages of the combined study include reductions in the number of animals required and cost. Although the rat is the routine species of choice, the mouse may also be used.

  9. Understanding landscape dynamics over thousand years : combining field and model work : with case study in the Drakensberg foothill, KwaZulu-Natal, South Africa

    NARCIS (Netherlands)

    Temme, A.J.A.M.

    2008-01-01

    The title of this thesis is “Understanding landscape dynamics over thousands of years : combining field and model work, with a case study in the Drakensberg Foothills, KwaZulu-Natal, South Africa”. As the title clearly states, the overall objective is an increased knowledge of landscape dynamics thr

  10. Probing of the combined effect of bisquaternary ammonium antimicrobial agents and acetylsalicylic acid on model phospholipid membranes: differential scanning calorimetry and mass spectrometry studies.

    Science.gov (United States)

    Kasian, N A; Pashynska, V A; Vashchenko, O V; Krasnikova, A O; Gömöry, A; Kosevich, M V; Lisetski, L N

    2014-12-01

    A model molecular biosystem of hydrated dipalmitoylphosphatidylcholine (DPPC) bilayers that mimics cell biomembranes is used to probe combined membranotropic effects of drugs by instrumental techniques of molecular biophysics. Differential scanning calorimetry reveals that doping of the DPPC model membrane with individual bisquaternary ammonium compounds (BQAC) decamethoxinum, ethonium, thionium and acetylsalicylic acid (ASA) leads to lowering of the membrane melting temperature (Tm) pointing to membrane fluidization. Combined application of the basic BQAC and acidic ASA causes an opposite effect on Tm (increase), corresponding to the membrane densification. Thus, modulation of the membranotropic effects upon combined use of the drugs studied can be revealed at the level of model membranes. Formation of noncovalent supramolecular complexes of the individual BQACs and ASA with DPPC molecules, which may be involved in the mechanism of the drug-membrane interaction at the molecular level, is demonstrated by electrospray ionization (ESI) mass spectrometry. In the ternary (DPPC + ASA + BQAC) model systems, the stable complexes of the BQAC dication with the ASA anion, which may be responsible for modulation of the membranotropic effects of the drugs, were recorded by ESI mass spectrometry. The proposed approach can be further developed for preliminary evaluation of the combined effects of the drugs at the level of model lipid membranes prior to tests on living organisms.

  11. Combined density functional/polarizable continuum model study of magnetochiral birefringence: Can theory and experiment be brought to agreement?

    Science.gov (United States)

    Jansík, Branislav; Rizzo, Antonio; Frediani, Luca; Ruud, Kenneth; Coriani, Sonia

    2006-12-01

    The magnetic-field-induced axial birefringence (magnetochirality) of five closed-shell chiral molecules (three substituted oxiranes, carvone, and limonene) is studied at the density functional theory level using Becke's 3-parameter Lee-Yang-Parr functional and frequency-dependent quadratic response theory. The influence of the environment and the conformational distribution on the property is also studied. The environment effects are described by the polarizable continuum model in its integral-equation formulation. The effect of the conformational distribution is investigated by performing calculations on several conformers—for carvone and limonene—followed by Boltzmann averaging. The calculated values for the magnetochiral birefringence are compared to previous ab initio results and experimental data where available. The refined model presented here brings the ab initio values closer to experiment. Still, disagreements remain in some cases and it appears difficult to resolve these discrepancies.

  12. A study of an effective sunitinib–chemotherapeutic combination regimen for bladder cancer treatment using a mouse model

    Directory of Open Access Journals (Sweden)

    Dah-Shyong Yu

    2014-06-01

    Conclusion: Combination of the tyrosine kinase receptor inhibitor sunitinib with gemcitabine chemotherapy synergistically enhances tumor cytotoxicity and may provide a new treatment modality for advanced bladder cancer.

  13. Study protocol: combining experimental methods, econometrics and simulation modelling to determine price elasticities for studying food taxes and subsidies (The Price ExaM Study).

    Science.gov (United States)

    Waterlander, Wilma E; Blakely, Tony; Nghiem, Nhung; Cleghorn, Christine L; Eyles, Helen; Genc, Murat; Wilson, Nick; Jiang, Yannan; Swinburn, Boyd; Jacobi, Liana; Michie, Jo; Ni Mhurchu, Cliona

    2016-07-19

    There is a need for accurate and precise food price elasticities (PE, change in consumer demand in response to change in price) to better inform policy on health-related food taxes and subsidies. The Price Experiment and Modelling (Price ExaM) study aims to: I) derive accurate and precise food PE values; II) quantify the impact of price changes on quantity and quality of discrete food group purchases and; III) model the potential health and disease impacts of a range of food taxes and subsidies. To achieve this, we will use a novel method that includes a randomised Virtual Supermarket experiment and econometric methods. Findings will be applied in simulation models to estimate population health impact (quality-adjusted life-years [QALYs]) using a multi-state life-table model. The study will consist of four sequential steps: 1. We generate 5000 price sets with random price variation for all 1412 Virtual Supermarket food and beverage products. Then we add systematic price variation for foods to simulate five taxes and subsidies: a fruit and vegetable subsidy and taxes on sugar, saturated fat, salt, and sugar-sweetened beverages. 2. Using an experimental design, 1000 adult New Zealand shoppers complete five household grocery shops in the Virtual Supermarket where they are randomly assigned to one of the 5000 price sets each time. 3. Output data (i.e., multiple observations of price configurations and purchased amounts) are used as inputs to econometric models (using Bayesian methods) to estimate accurate PE values. 4. A disease simulation model will be run with the new PE values as inputs to estimate QALYs gained and health costs saved for the five policy interventions. The Price ExaM study has the potential to enhance public health and economic disciplines by introducing internationally novel scientific methods to estimate accurate and precise food PE values. These values will be used to model the potential health and disease impacts of various food pricing policy

  14. Thermoeconomic Modeling and Parametric Study of a Photovoltaic-Assisted 1 MWe Combined Cooling, Heating, and Power System

    Directory of Open Access Journals (Sweden)

    Alexandros Arsalis

    2016-08-01

    Full Text Available In this study a small-scale, completely autonomous combined cooling, heating, and power (CCHP system is coupled to a photovoltaic (PV subsystem, to investigate the possibility of reducing fuel consumption. The CCHP system generates electrical energy with the use of a simple gas turbine cycle, with a rated nominal power output of 1 MWe. The nominal power output of the PV subsystem is examined in a parametric study, ranging from 0 to 600 kWe, to investigate which configuration results in a minimum lifecycle cost (LCC for a system lifetime of 20 years of service. The load profile considered is applied for a complex of households in Nicosia, Cyprus. The solar data for the PV subsystem are taken on an hourly basis for a whole year. The results suggest that apart from economic benefits, the proposed system also results in high efficiency and reduced CO2 emissions. The parametric study shows that the optimum PV capacity is 300 kWe. The minimum lifecycle cost for the PV-assisted CCHP system is found to be 3.509 million €, as compared to 3.577 million € for a system without a PV subsystem. The total cost for the PV subsystem is 547,445 €, while the total cost for operating the system (fuel is 731,814 € (compared to 952,201 € for a CCHP system without PVs. Overall the proposed system generates a total energy output of 210,520 kWh (during its whole lifetime, which translates to a unit cost of 17 €/kWh.

  15. The discovery of potential acetylcholinesterase inhibitors: A combination of pharmacophore modeling, virtual screening, and molecular docking studies

    Directory of Open Access Journals (Sweden)

    Chuang Chih-Kuang

    2011-01-01

    Full Text Available Abstract Background Alzheimer's disease (AD is the most common cause of dementia characterized by progressive cognitive impairment in the elderly people. The most dramatic abnormalities are those of the cholinergic system. Acetylcholinesterase (AChE plays a key role in the regulation of the cholinergic system, and hence, inhibition of AChE has emerged as one of the most promising strategies for the treatment of AD. Methods In this study, we suggest a workflow for the identification and prioritization of potential compounds targeted against AChE. In order to elucidate the essential structural features for AChE, three-dimensional pharmacophore models were constructed using Discovery Studio 2.5.5 (DS 2.5.5 program based on a set of known AChE inhibitors. Results The best five-features pharmacophore model, which includes one hydrogen bond donor and four hydrophobic features, was generated from a training set of 62 compounds that yielded a correlation coefficient of R = 0.851 and a high prediction of fit values for a set of 26 test molecules with a correlation of R2 = 0.830. Our pharmacophore model also has a high Güner-Henry score and enrichment factor. Virtual screening performed on the NCI database obtained new inhibitors which have the potential to inhibit AChE and to protect neurons from Aβ toxicity. The hit compounds were subsequently subjected to molecular docking and evaluated by consensus scoring function, which resulted in 9 compounds with high pharmacophore fit values and predicted biological activity scores. These compounds showed interactions with important residues at the active site. Conclusions The information gained from this study may assist in the discovery of potential AChE inhibitors that are highly selective for its dual binding sites.

  16. STUDY OF ANTIMICROBIAL ACTIVITY OF NEW COMBINED OINTMENT ON THE MODEL OF PURULENT WOUND OF STAPHYLOCOCCAL ETIOLOGY

    Directory of Open Access Journals (Sweden)

    Tkachova O.V.

    2015-05-01

    Full Text Available Introduction. Prevalence of purulent pathologies and insufficient number of combined ointments with multi-effect on inflammation, infection and tissue damage are a prerequisite for scientists of NUPh to develop a new combined ointment composed of: antiseptics ethacridine lactate and thick chlorophyllipt extract, drug with reparative and anti-inflammatory activity – dexpanthenol, PEG-base of the IInd generation with the moderate dehydrating activity (180%. The range of pharmacological actions of Filetol ointment meets local therapy requirements in the IInd phase of the wound healing process. New ointment can also be applied in the Ist phase of wound healing process, if the wound contains a small amount of purulent exudate or does not contain it at all. Material & Methods. The purulent wound of staphylococcal etiology was reproduced in 24 white mature female mice weighing 14-17 g and subcutaneously injected with 0.2 ml of 10% solution of calcium chloride in the skin area, depilated beforehand, and after the development of necrosis on the 4th day injected with 0.2 ml of daily agar cultures S. aureus ATCC 25923 in the necrotizing area. In 48 hours of the infection, in the area of administration of staphylococcus cultures purulent necrotic wounds developed, which, depending on the size and intensity of the lesions, were subjected to reverse development in 9-15 days in a row. Animals were divided into three groups of 8 animals, including a positive control group, animals in which were not treated. In this study, the comparator was Levomecol ointment which is widely used in clinical practice for the local treatment of purulent wounds. Efficacy of treatment was evaluated on the basis of lesion value and intensity in study groups compared with the positive control, animal deaths in the case of generalization of the purulent process, quantitative dynamics of microorganisms in the wound and planimetric indicators (area of wounds and the percentage of

  17. Hemodynamic effects of combined focal cerebral ischemia and amyloid protein toxicity in a rat model: a functional CT study.

    Directory of Open Access Journals (Sweden)

    Jun Yang

    Full Text Available BACKGROUND/OBJECTIVE: Clinical evidence indicates that cerebral ischemia (CI and a pathological factor of Alzheimer's disease, the β-amyloid (Aβ protein, can increase the rate of cognitive impairment in the ageing population. Using the CT Perfusion (CTP functional imaging, we sought to investigate the interaction between CI and the Aβ protein on cerebral hemodynamics. METHODS: A previously established rat model of CI and Aβ was used for the CTP study. Iodinated contrast was given intravenously, while serial CT images of sixteen axial slices were acquired. Cerebral blood flow (CBF and blood volume (CBV parametric maps were co-registered to a rat brain atlas and regions of interest were drawn on the maps. Microvascular alteration was investigated with histopathology. RESULTS: CTP results revealed that ipsilateral striatum of Aβ+CI and CI groups showed significantly lower CBF and CBV than control at the acute phase. Striatal CBF and CBV increased significantly at week 1 in the CI and Aβ+CI groups, but not in the Aβ alone or control group. Histopathology showed that average density of dilated microvessels in the ipsilateral striatum in CI and Aβ+CI groups was significantly higher than control at week 1, indicating this could be associated with hyperperfusion and hypervolemia observed from CTP results. CONCLUSION: These results demonstrate that CTP can quantitatively measure the hemodynamic disturbance on CBF and CBV functional maps in a rat model of CI interacting with Aβ.

  18. Combining Model-Based and Feature-Driven Diagnosis Approaches – A Case Study on Electromechanical Actuators

    Data.gov (United States)

    National Aeronautics and Space Administration — Model-based diagnosis typically uses analytical redundancy to compare predictions from a model against observations from the system being diagnosed. However this...

  19. A hybrid Bayesian hierarchical model combining cohort and case-control studies for meta-analysis of diagnostic tests: Accounting for partial verification bias.

    Science.gov (United States)

    Ma, Xiaoye; Chen, Yong; Cole, Stephen R; Chu, Haitao

    2014-05-26

    To account for between-study heterogeneity in meta-analysis of diagnostic accuracy studies, bivariate random effects models have been recommended to jointly model the sensitivities and specificities. As study design and population vary, the definition of disease status or severity could differ across studies. Consequently, sensitivity and specificity may be correlated with disease prevalence. To account for this dependence, a trivariate random effects model had been proposed. However, the proposed approach can only include cohort studies with information estimating study-specific disease prevalence. In addition, some diagnostic accuracy studies only select a subset of samples to be verified by the reference test. It is known that ignoring unverified subjects may lead to partial verification bias in the estimation of prevalence, sensitivities, and specificities in a single study. However, the impact of this bias on a meta-analysis has not been investigated. In this paper, we propose a novel hybrid Bayesian hierarchical model combining cohort and case-control studies and correcting partial verification bias at the same time. We investigate the performance of the proposed methods through a set of simulation studies. Two case studies on assessing the diagnostic accuracy of gadolinium-enhanced magnetic resonance imaging in detecting lymph node metastases and of adrenal fluorine-18 fluorodeoxyglucose positron emission tomography in characterizing adrenal masses are presented.

  20. Design of Safer Flame Retardant Textiles through Inclusion Complex Formation with Cyclodextrins: A Combined Experimental and Modeling Study

    Science.gov (United States)

    Zhang, Nanshan

    size mismatch between them. A novel analytical chemistry technique - tandem mass spectrometry (ESI-Q-TOF) was used to study the inclusion complexes of TPP and CDs. Successful formation of TPP-beta-/gamma-CD-IC was further proved by ESI mass spec in the positive mode. Experimental results demonstrated that 1:1 inclusion complex ions of the guest FR and the host CDs were detected. Experimentally alpha-CD cannot form an IC with TPP and this was further confirmed by tandem mass spec. Mass spectrometry provides a fast and accurate method to investigate cyclodextrin inclusion complexes and verify the formation of ICs. Computational methods were applied to help understand the energetically favorable geometry of TPP and beta-/gamma-CD in their IC form. Semi-empirical theoretical methods (PM3 and PM6) were used to find the global minima of TPP-CD geometry and density functional theory calculations at a B3LYP/6-31G(d) level were employed for elaborate geometry optimization. Solvent effect was also considered using the polarized continuum model (IEF-PCM). Analysis of the results indicated that after optimization, IC geometries provided by PM6 had stronger interactions and were more energetically favorable than the ones calculated by PM3. DFT calculations are more accurate than PM3/PM6 and enabled more interactions between the host and the guest than two semi-empirical approaches. DFT calculations also proved that initial structures prepared by PM6 were more favorable in H-bonding profiles and key energy parameters. For TPP-beta-CD system in vacuum and water, Model A owned a lower total and complexation energy while a stronger interaction between them was present in Model B. In TPP-gamma-CD system, Model B was preferred than Model A in both vacuum and water. This was potentially attributed to more H-bonds formed between TPP and gamma-CD in Model B and its ability to retain most of the internal linkages among primary hydroxyl groups.

  1. Combination of capillary electrophoresis, molecular modeling and NMR to study the enantioselective complexation of sulpiride with double cyclodextrin systems.

    Science.gov (United States)

    Melani, Fabrizio; Pasquini, Benedetta; Caprini, Claudia; Gotti, Roberto; Orlandini, Serena; Furlanetto, Sandra

    2015-10-10

    The enantioselective complexation of sulpiride by a number of cyclodextrins (CDs) was deeply investigated by different techniques with the aim of evaluating the role of the used chiral selectors involved in the enantioseparation of the eutomer levosulpiride (S-SUL) and its dextro-isomer by capillary electrophoresis (CE). A CE method was previously developed with the aim of determining the optical purity of S-SUL and was based on the use of a dual cyclodextrin system, made by sulfated-β-cyclodextrin (SβCD) and methyl-β-cyclodextrin (MβCD). In this paper, a molecular modeling study made it possible to explain the different affinity of sulpiride enantiomers for several CDs, which had been tested during the early phase of CE method development. The potential and the gain energy of the inclusion complexes between the enantiomers and neutral and charged CDs were calculated on the minimized conformations. The calculated docking energies indicated that the most stable complexes were effectively obtained with SβCD and MβCD. A correlation between CE migration time of the last migrating enantiomer S-SUL and the stability of analyte-neutral CDs complexes was postulated. Furthermore, two-dimensional rotating-frame Overhauser effect spectroscopy NMR (2-D ROESY) experiments were carried out, which clearly indicated the formation of complexes and suggested the inclusion of the benzene sulfonamide moiety of S-SUL inside the hydrophobic cavity of the CDs.

  2. Insights into mechanisms of intestinal segmentation in guinea pigs: a combined computational modeling and in vitro study.

    Science.gov (United States)

    Chambers, Jordan D; Bornstein, Joel C; Thomas, Evan A

    2008-09-01

    Segmentation in the guinea pig small intestine consists of a number of discrete motor patterns including rhythmic stationary contractions that occur episodically at specific locations along the intestine. The enteric nervous system regulates segmentation, but the exact circuit is unknown. Using simple computer models, we investigated possible circuits. Our computational model simulated the mean neuron firing rate in the feedforward ascending and descending reflex pathways. A stimulus-evoked pacemaker was located in the afferent pathway or in a feedforward pathway. Output of the feedforward pathways was fed into a simple model to determine the response of the muscle. Predictions were verified in vitro by using guinea pig jejunum, in which segmentation was induced with luminal fatty acid. In the computational model, local stimuli produced an oral contraction and anal dilation, similar to in vitro responses to local distension, but did not produce segmentation. When the stimulus was distributed, representing a nutrient load, the result was either a tonic response or globally synchronized oscillations. However, when we introduced local variations in synaptic coupling, stationary contractions occurred around these locations. This predicts that severing the ascending and descending pathways will induce stationary contractions. An acute lesion in our in vitro model significantly increased the number of stationary contractions immediately oral and anal to the lesion. Our results suggest that spatially localized rhythmic contractions arise from a local imbalance between ascending excitatory and descending inhibitory muscle inputs and require a distributed stimulus and a rhythm generator in the afferent pathway.

  3. Analysis on Adhesively-Bonded Joints of FRP-steel Composite Bridge under Combined Loading: Arcan Test Study and Numerical Modeling

    Directory of Open Access Journals (Sweden)

    Xu Jiang

    2016-01-01

    Full Text Available The research presented in this paper is an experimental study and numerical analysis on mechanical behavior of the adhesively-bonded joint between FRP sandwich bridge deck and steel girder. Generally, there are three typical stress states in the adhesively-bonded joint: shear stress, tensile stress, and combination of both. To realize these stress states in the adhesively-bonded joint during tests, a specific loading device is developed with the capacity of providing six different loading angles, which are 0°(pure tension, 18°, 36°, 54°, 72° and 90°(pure shear. Failure modes of adhesively-bonded joints are investigated. It indicates that, for the pure shear loading, the failure mode is the cohesive failure (near the interface between the adhesive layer and the steel support in the adhesive layer. For the pure tensile and combined loading conditions, the failure mode is the combination of fiber breaking, FRP delamination and interfacial adhesion failure between the FRP sandwich deck and the adhesive layer. The load-bearing capacities of adhesive joints under combined loading are much lower than those of the pure tensile and pure shear loading conditions. According to the test results of six angle loading conditions, a tensile/shear failure criterion of the adhesively-bonded joint is obtained. By using Finite Element (FE modeling method, linear elastic simulations are performed to characterize the stress distribution throughout the adhesively-bonded joint.

  4. Competing intermolecular interactions of artemisinin-type agents and aspirin with membrane phospholipids: Combined model mass spectrometry and quantum-chemical study

    Energy Technology Data Exchange (ETDEWEB)

    Pashynska, Vlada, E-mail: vlada@vl.kharkov.ua [B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Lenin Ave., 47, 61103 Kharkov (Ukraine); Stepanian, Stepan [B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Lenin Ave., 47, 61103 Kharkov (Ukraine); Gömöry, Agnes; Vekey, Karoly [Institute of Organic Chemistry of Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudosok korutja, 2, Budapest H-1117 (Hungary); Adamowicz, Ludwik [University of Arizona, Department of Chemistry and Biochemistry, Tucson, AZ 85721 (United States)

    2015-07-09

    Highlights: • Competitive binding of artemisinin agents and aspirin with phospholipids is shown. • Complexation between the antimalarial drugs and aspirin molecules is also found. • Energetically favorable structures of the model complexes are identified by DFT. • Membranotropic activity of the studied drugs can be modified under joint usage. - Abstract: Study of intermolecular interactions of antimalarial artemisinin-type drugs and aspirin with membrane phospholipids is important in term of elucidation of the drugs activity modification under their joint usage. Combined experimental and computational study of the interaction of dihydroartemisinin, α-artemether, and artesunate with aspirin (ASP) and dipalmitoylphosphatidylcholine (DPPC) is performed by electrospray ionization (ESI) mass spectrometry and by DFT B3LYP/aug-cc-pVDZ methods. The results of the ESI investigation of systems containing artemisinin-type agent, ASP and DPPC, reveal a competition between the antimalarial agents and ASP for binding with DPPC molecules. The complexation between the antimalarial drugs and ASP is also found. Observed phenomena suggest that membranotropic activity of artemisin-type agents and aspirin is modified under their combined usage. To elucidate structure-energy characteristics of the non-covalent complexes studied the model DFT calculations are performed for dihydroartemisinin · ASP complex and complexes of the each drug with phosphatidylcholine head of DPPC in neutral and cationized forms.

  5. Volume-based solvation models out-perform area-based models in combined studies of wild-type and mutated protein-protein interfaces

    Directory of Open Access Journals (Sweden)

    Warwicker Jim

    2008-10-01

    Full Text Available Abstract Background Empirical binding models have previously been investigated for the energetics of protein complexation (ΔG models and for the influence of mutations on complexation (i.e. differences between wild-type and mutant complexes, ΔΔG models. We construct binding models to directly compare these processes, which have generally been studied separately. Results Although reasonable fit models were found for both ΔG and ΔΔG cases, they differ substantially. In a dataset curated for the absence of mainchain rearrangement upon binding, non-polar area burial is a major determinant of ΔG models. However this ΔG model does not fit well to the data for binding differences upon mutation. Burial of non-polar area is weighted down in fitting of ΔΔG models. These calculations were made with no repacking of sidechains upon complexation, and only minimal packing upon mutation. We investigated the consequences of more extensive packing changes with a modified mean-field packing scheme. Rather than emphasising solvent exposure with relatively extended sidechains, rotamers are selected that exhibit maximal packing with protein. This provides solvent accessible areas for proteins that are much closer to those of experimental structures than the more extended sidechain regime. The new packing scheme increases changes in non-polar burial for mutants compared to wild-type proteins, but does not substantially improve agreement between ΔG and ΔΔG binding models. Conclusion We conclude that solvent accessible area, based on modelled mutant structures, is a poor correlate for ΔΔG upon mutation. A simple volume-based, rather than solvent accessibility-based, model is constructed for ΔG and ΔΔG systems. This shows a more consistent behaviour. We discuss the efficacy of volume, as opposed to area, approaches to describe the energetic consequences of mutations at interfaces. This knowledge can be used to develop simple computational screens for

  6. Structural Studies of Phycobiliproteins from Spirulina: Combining Spectroscopy, Thermodynamics, and Molecular Modeling in an Undergraduate Biochemistry Experiment

    Science.gov (United States)

    Taylor, Ann T. S.; Feller, Scott E.

    2002-12-01

    Molecular modeling provides a powerful mechanism for students to connect molecular-level structural changes with macroscopically observable properties. We describe an experiment that integrates spectroscopy, thermodynamics, and molecular modeling into a single activity examining structural changes in phycobiliproteins upon denaturation with urea. Phycobiliproteins contain a covalently attached chromophore, phycocyanobilin, which is constrained in a planar conformation by the folded protein. Upon denaturation of the protein, the chromophore undergoes a conformational change, leading to a significant alteration of the absorption spectrum. By measuring the absorbance at 625 nm as a function of urea concentration, the free energy of unfolding can be determined. Students determine the dihedral angles in the chromophore and map the contacts between protein and chromophore using Protein Explorer, a structure visualization program freely available on the Internet. The change in absorption wavelength can be related to the difference between the LUMO and HOMO energies, obtained using PC Spartan Pro, for the chromophore in the folded and unfolded phycobiliprotein. This experiment could be used in a physical chemistry class in a curriculum that integrates biochemistry throughout the course work as well as in a traditional biochemistry course. Featured on the Cover

  7. Comparison and combination of a hemodynamics/biomarkers-based model with simplified PESI score for prognostic stratification of acute pulmonary embolism: findings from a real world study

    Directory of Open Access Journals (Sweden)

    Luca Masotti

    2015-11-01

    Full Text Available Background: Prognostic stratification is of utmost importance for management of acute Pulmonary Embolism (PE in clinical practice. Many prognostic models have been proposed, but which is the best prognosticator in real life remains unclear. The aim of our study was to compare and combine the predictive values of the hemodynamics/biomarkers based prognostic model proposed by European Society of Cardiology (ESC in 2008 and simplified PESI score (sPESI. Methods: Data records of 452 patients discharged for acute PE from Internal Medicine wards of Tuscany (Italy were analysed. The ESC model and sPESI were retrospectively calculated and compared by using Areas under Receiver Operating Characteristics (ROC Curves (AUCs and finally the combination of the two models was tested in hemodinamically stable patients. All cause and PE-related in-hospital mortality and fatal or major bleedings were the analyzed endpoints Results: All cause in-hospital mortality was 25% (16.6% PE related in high risk, 8.7% (4.7% in intermediate risk and 3.8% (1.2% in low risk patients according to ESC model. All cause in-hospital mortality was 10.95% (5.75% PE related in patients with sPESI score and #8805;1 and 0% (0% in sPESI score 0. Predictive performance of sPESI was not significantly different compared with 2008 ESC model both for all cause (AUC sPESI 0.711, 95% CI: 0.661-0.758 versus ESC 0.619, 95% CI: 0.567-0.670, difference between AUCs 0.0916, p=0.084 and for PE-related mortality (AUC sPESI 0.764, 95% CI: 0.717-0.808 versus ESC 0.650, 95% CI: 0.598-0.700, difference between AUCs 0.114, p=0.11. Fatal or major bleedings occurred in 4.30% of high risk, 1.60% of intermediate risk and 2.50% of low risk patients according to 2008 ESC model, whereas these occurred in 1.80% of high risk and 1.45% of low risk patients according to sPESI, respectively. Predictive performance for fatal or major bleeding between two models was not significantly different (AUC sPESI 0.658, 95% CI

  8. Temperature-pressure phase diagram of a heterogeneous anionic model biomembrane system: results from a combined calorimetry, spectroscopy and microscopy study.

    Science.gov (United States)

    Kapoor, Shobhna; Werkmüller, Alexander; Denter, Christian; Zhai, Yong; Markgraf, Jonas; Weise, Katrin; Opitz, Norbert; Winter, Roland

    2011-04-01

    By using Fourier transform infrared (FT-IR) spectroscopy in combination with differential scanning calorimetry (DSC) coupled with pressure perturbation calorimetry (PPC), ultrasound velocimetry, Laurdan fluorescence spectroscopy, fluorescence microscopy and atomic force microscopy (AFM), the temperature and pressure dependent phase behavior of the five-component anionic model raft lipid mixture DOPC/DOPG/DPPC/DPPG/cholesterol (20:5:45:5:25 mol%) was investigated. A temperature range from 5 to 65 °C and a pressure range up to 16 kbar were covered to establish the temperature-pressure phase diagram of this heterogeneous model biomembrane system. Incorporation of 10-20 mol% PG still leads to liquid-ordered (l(o))-liquid-disordered (l(d)) phase coexistence regions over a wide range of temperatures and pressures. Compared to the corresponding neutral model raft mixture (DOPC/DPPC/Chol 25:50:25 mol%), the p,T-phase diagram is - as expected and in accordance with the Gibbs phase rule - more complex, the phase sequence as a function of temperature and pressure is largely similar, however. This anionic heterogeneous model membrane system will serve as a more realistic model biomembrane system to study protein interactions with anionic lipid bilayers displaying liquid-disordered/liquid-ordered domain coexistence over a wide range of the temperature-pressure plane, thus allowing also studies of biologically relevant systems encountered under extreme environmental conditions.

  9. Dietary Supplementation with a Combination of Lactoferrin, Fish Oil, and Enterococcus faecium WB2000 for Treating Dry Eye: A Rat Model and Human Clinical Study.

    Science.gov (United States)

    Kawashima, Motoko; Nakamura, Shigeru; Izuta, Yusuke; Inoue, Sachiko; Tsubota, Kazuo

    2016-04-01

    To examine the effect of a combined dietary supplement containing fish oil, lactoferrin, zinc, vitamin C, lutein, vitamin E, γ-aminobutanoic acid, and Enterococcus faecium WB2000 on dry eye. A preliminary study in a rat model and a prospective, randomized, double-blind, placebo-controlled study in humans were conducted. Forty Japanese volunteers aged 22 to 59 years were randomized into combined dietary supplement (2 capsules/day; 20 participants) and placebo (vehicle; 19 participants) groups and treated once daily for 8 weeks. Rats received the combined dietary supplement components (10 or 50 mg/kg orally) or vehicle (2% DMSO), and dry eye was mechanically induced for 2 days. Tear production was measured in rats after dry eye was induced. Humans were assessed at baseline and weeks 4 and 8 post-supplementation based on keratoconjunctival epithelial damage; fluorescein tear film breakup time; tear production; biochemical data; information regarding subjective dry eye symptoms by answering a questionnaire; and information regarding adverse events via medical interviews. Supplementation dose-dependently mitigated the decrease in tear production in rats. Among subjects with confirmed dry eye, clinical symptoms improved at weeks 4 and 8 more significantly in the supplementation group than in the placebo group (P<.05). The rate of increase in the Schirmer value was greater in the supplementation group. No adverse events occurred. Supplementation improved objective and subjective dry eye symptoms. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Molecular modeling study of CP-690550 derivatives as JAK3 kinase inhibitors through combined 3D-QSAR, molecular docking, and dynamics simulation techniques.

    Science.gov (United States)

    Wang, Jing Li; Cheng, Li Ping; Wang, Tian Chi; Deng, Wei; Wu, Fan Hong

    2017-03-01

    To develop more potent JAK3 kinase inhibitors, a series of CP-690550 derivatives were investigated using combined molecular modeling techniques, such as 3D-QSAR, molecular docking and molecular dynamics (MD). The leave-one-out correlation (q(2)) and non-cross-validated correlation coefficient (r(2)) of the best CoMFA model are 0.715 and 0.992, respectively. The q(2) and r(2) values of the best CoMSIA model are 0.739 and 0.995, respectively. The steric, electrostatic, and hydrophobic fields played important roles in determining the inhibitory activity of CP-690550 derivatives. Some new JAK3 kinase inhibitors were designed. Some of them have better inhibitory activity than the most potent Tofacitinib (CP-690550). Molecular docking was used to identify some key amino acid residues at the active site of JAK3 protein. 10ns MD simulations were successfully performed to confirm the detailed binding mode and validate the rationality of docking results. The calculation of the binding free energies by MMPBSA method gives a good correlation with the predicted biological activity. To our knowledge, this is the first report on MD simulations and free energy calculations for this series of compounds. The combination results of this study will be valuable for the development of potent and novel JAK3 kinase inhibitors. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Masitinib combined with standard gemcitabine chemotherapy: in vitro and in vivo studies in human pancreatic tumour cell lines and ectopic mouse model.

    Directory of Open Access Journals (Sweden)

    Martine Humbert

    Full Text Available BACKGROUND: Tyrosine kinases are attractive targets for pancreatic cancer therapy because several are over-expressed, including PDGFRalpha/beta, FAK, Src and Lyn. A critical role of mast cells in the development of pancreatic cancer has also been reported. Masitinib is a tyrosine kinase inhibitor that selectively targets c-Kit, PDGFRalpha/beta, Lyn, and to a lesser extent the FAK pathway, without inhibiting kinases of known toxicities. Masitinib is particularly efficient in controlling the proliferation, differentiation and degranulation of mast cells. This study evaluates the therapeutic potential of masitinib in pancreatic cancer, as a single agent and in combination with gemcitabine. METHODOLOGY/FINDINGS: Proof-of-concept studies were performed in vitro on human pancreatic tumour cell lines and then in vivo using a mouse model of human pancreatic cancer. Molecular mechanisms were investigated via gene expression profiling. Masitinib as a single agent had no significant antiproliferative activity while the masitinib/gemcitabine combination showed synergy in vitro on proliferation of gemcitabine-refractory cell lines Mia Paca2 and Panc1, and to a lesser extent in vivo on Mia Paca2 cell tumour growth. Specifically, masitinib at 10 microM strongly sensitised Mia Paca2 cells to gemcitabine (>400-fold reduction in IC(50; and moderately sensitised Panc1 cells (10-fold reduction. Transcriptional analysis identified the Wnt/beta-catenin signalling pathway as down-regulated in the cell lines resensitised by the masitinib/gemcitabine combination. CONCLUSIONS: These data establish proof-of-concept that masitinib can sensitise gemcitabine-refractory pancreatic cancer cell lines and warrant further in vivo investigation. Indeed, such an effect has been recently observed in a phase 2 clinical study of patients with pancreatic cancer who received a masitinib/gemcitabine combination.

  12. Prediction of in vivo embryotoxic effect levels with a combination of in vitro studies and PBPK modelling

    NARCIS (Netherlands)

    Verwei, M.; Burgsteden, J.A. van; Krul, C.A.M.; Sandt, J.J.M. van de; Freidig, A.P.

    2006-01-01

    The new EU legislations for chemicals (Registration, Evaluation and Authorization of Chemicals, REACH) and cosmetics (Seventh Amendment) stimulate the acceptance of in vitro and in silico approaches to test chemicals for their potential to cause reproductive effects. In the current study seven compo

  13. Self-assembly Controls Self-cleavage of HHR from ASBVd (−): a Combined SANS and Modeling Study

    Science.gov (United States)

    Leclerc, Fabrice; Zaccai, Giuseppe; Vergne, Jacques; Řìhovà, Martina; Martel, Anne; Maurel, Marie-Christine

    2016-01-01

    In the Avocado Sunblotch Viroid (ASBVd: 249-nt) from the Avsunviroidae family, a symmetric rolling-circle replication operates through an autocatalytic mechanism mediated by hammerhead ribozymes (HHR) embedded in both polarity strands. The concatenated multimeric ASBVd (+) and ASBVd (−) RNAs thus generated are processed by cleavage to unit-length where ASBVd (−) self-cleaves with more efficiency. Absolute scale small angle neutron scattering (SANS) revealed a temperature-dependent dimer association in both ASBVd (−) and its derived 79-nt HHR (−). A joint thermodynamic analysis of SANS and catalytic data indicates the rate-determining step corresponds to the dimer/monomer transition. 2D and 3D models of monomeric and dimeric HHR (−) suggest that the inter-molecular contacts stabilizing the dimer (between HI and HII domains) compete with the intra-molecular ones stabilizing the active conformation of the full-length HHR required for an efficient self-cleavage. Similar competing intra- and inter-molecular contacts are proposed in ASBVd (−) though with a remoter region from an extension of the HI domain. PMID:27456224

  14. Self-assembly Controls Self-cleavage of HHR from ASBVd (-): a Combined SANS and Modeling Study

    Science.gov (United States)

    Leclerc, Fabrice; Zaccai, Giuseppe; Vergne, Jacques; Řìhovà, Martina; Martel, Anne; Maurel, Marie-Christine

    2016-07-01

    In the Avocado Sunblotch Viroid (ASBVd: 249-nt) from the Avsunviroidae family, a symmetric rolling-circle replication operates through an autocatalytic mechanism mediated by hammerhead ribozymes (HHR) embedded in both polarity strands. The concatenated multimeric ASBVd (+) and ASBVd (-) RNAs thus generated are processed by cleavage to unit-length where ASBVd (-) self-cleaves with more efficiency. Absolute scale small angle neutron scattering (SANS) revealed a temperature-dependent dimer association in both ASBVd (-) and its derived 79-nt HHR (-). A joint thermodynamic analysis of SANS and catalytic data indicates the rate-determining step corresponds to the dimer/monomer transition. 2D and 3D models of monomeric and dimeric HHR (-) suggest that the inter-molecular contacts stabilizing the dimer (between HI and HII domains) compete with the intra-molecular ones stabilizing the active conformation of the full-length HHR required for an efficient self-cleavage. Similar competing intra- and inter-molecular contacts are proposed in ASBVd (-) though with a remoter region from an extension of the HI domain.

  15. Evaluation criteria for AIS 1 neck injuries in frontal impacts--a parameter study combining field data and Madymo modeling.

    Science.gov (United States)

    Jakobsson, Lotta; Lundgren, Kristina; Norin, Hans; Svensson, Mats

    2004-12-01

    Two situations with an expected higher AIS 1 neck injury rate in frontal impact were compared to a reference situation using a Madymo human body model in three different sitting postures and four different crash pulses. The two situations were reduced occupant weight and occupant with initial forward arm resistance, respectively. Occupant neck motion phases were identified and corresponding possible evaluation criteria were evaluated within the phases. Typical neck kinematics was seen for the two different situations. Occupants of lower weight had a more extended neck in the initial protraction phase and also a generally more pronounced upper neck link angle. Occupants with initial arm resistance had generally greater lower neck link angle at the time when the upper neck link angle was straight. No evaluation criteria reflected the anticipated AIS 1 neck injury rate consistently. In the initial protraction phase, NICmin correlated to expected injury outcome in almost half of the cases. In the protraction-flexion shift phase, Nkm, Nij, upper neck shear force and neck tension force reflected anticipated severity outcome to some extent. In the flexion phase, upper and lower neck extension correlated to anticipated AIS 1 neck injury rate only to a minor extent. The different sitting postures were more influential than the different crash pulses, emphasizing the importance of not only considering the spectra of impact severity but also differences in sitting postures in safety system development and evaluation.

  16. New insights into the tropospheric oxidation of isoprene: combining field measurements, laboratory studies, chemical modelling and quantum theory.

    Science.gov (United States)

    Whalley, Lisa; Stone, Daniel; Heard, Dwayne

    2014-01-01

    In this chapter we discuss some of the recent work directed at further understanding the chemistry of our atmosphere in regions of low NO x , such as forests, where there are considerable emissions of biogenic volatile organic compounds, for example reactive hydrocarbons such as isoprene. Recent field measurements have revealed some surprising results, for example that OH concentrations are measured to be considerably higher than can be understood using current chemical mechanisms. It has also not proven possible to reconcile field measurements of other species, such as oxygenated VOCs, or emission fluxes of isoprene, using current mechanisms. Several complementary approaches have been brought to bear on formulating a solution to this problem, namely field studies using state-of-the-art instrumentation, chamber studies to isolate sub-sections of the chemistry, laboratory studies to measure rate coefficients, product branching ratios and photochemical yields, the development of ever more detailed chemical mechanisms, and high quality ab initio quantum theory to calculate the energy landscape for relevant reactions and to enable the rates of formation of products and intermediates for previously unknown and unstudied reactions to be predicted. The last few years have seen significant activity in this area, with several contrasting postulates put forward to explain the experimental findings, and here we attempt to synthesise the evidence and ideas.

  17. Combining gene expression, demographic and clinical data in modeling disease: a case study of bipolar disorder and schizophrenia

    Directory of Open Access Journals (Sweden)

    Dobrin Seth

    2008-11-01

    Full Text Available Abstract Background This paper presents a retrospective statistical study on the newly-released data set by the Stanley Neuropathology Consortium on gene expression in bipolar disorder and schizophrenia. This data set contains gene expression data as well as limited demographic and clinical data for each subject. Previous studies using statistical classification or machine learning algorithms have focused on gene expression data only. The present paper investigates if such techniques can benefit from including demographic and clinical data. Results We compare six classification algorithms: support vector machines (SVMs, nearest shrunken centroids, decision trees, ensemble of voters, naïve Bayes, and nearest neighbor. SVMs outperform the other algorithms. Using expression data only, they yield an area under the ROC curve of 0.92 for bipolar disorder versus control, and 0.91 for schizophrenia versus control. By including demographic and clinical data, classification performance improves to 0.97 and 0.94 respectively. Conclusion This paper demonstrates that SVMs can distinguish bipolar disorder and schizophrenia from normal control at a very high rate. Moreover, it shows that classification performance improves by including demographic and clinical data. We also found that some variables in this data set, such as alcohol and drug use, are strongly associated to the diseases. These variables may affect gene expression and make it more difficult to identify genes that are directly associated to the diseases. Stratification can correct for such variables, but we show that this reduces the power of the statistical methods.

  18. Model studies for determining whether combined-cycle plants can participate in control of frequency and power flows in unified energy systems of Russia

    Science.gov (United States)

    Davydov, N. I.; Zorchenko, N. V.; Davydov, A. V.; Radin, Yu. A.

    2009-10-01

    Approximating transfer functions of a PGU-39 combined-cycle plant as a technological system with a controlled power output are presented, a structure of a system for automatic closed-loop control of the combined-cycle plant power output is proposed, and results from model investigations of this system are presented.

  19. Rapid breakthrough of pesticides via biopres into tile drains and shallow groundwater: a combined experimental and model study

    Science.gov (United States)

    Klaus, J.; Zehe, E.; Palm, J.; Schroeder, B.

    2009-04-01

    vertical soil profiles were excavated on the first day after the irrigation and two vertical profiles were excavated one week after the experiment. In those profiles soil samples were taken in a 10cm*10cm grid to analyse for the tracer concentrations. Based on that information the probability distribution function of the travel depths for each tracer could be calculated for two points in time. As burrows of deep digging earth worms often act as preferential pathways we counted the individuals of worm burrows using a nested sampling procedure. Though endogeic earthworms were apparent we didn't find any individuals of Lumbricus Terrestris nor macropores with diameter larger than 2 mm at a depth larger than 30-35 cm. So far we didn't identify those pathways that caused this rapid pesticide breakthrough into the tile drain, though a very small number macropores would suffice. Based on the collected data we will setup up a numerical model to simulate observed and flow and transport and test the hypothesis that earthworm burrows are the reason for this rapid breakthrough of pesticides into the tile drain.

  20. Upwelling dynamics in the Baltic Sea studied by a combined SAR/infrared satellite data and circulation model analysis

    Directory of Open Access Journals (Sweden)

    Evgenia Gurova

    2013-08-01

    Full Text Available The Damietta coast is part of the Egyptian Mediterranean coast off the Nile Delta and has recently been polluted as a result of intensive human activities.The environmental parameters and protozoan community in the area were studied biweekly from January to December 2007. The results of the environmentalparameters indicated low salinity, oxic and anoxic conditions, high nutrient levels and intensive phytoplankton growth. A total of 69 protozoan specieswere identified, belonging to Amoebozoa (8 species, Foraminifera (12 species, non-tintinnid ciliates (22 species and tintinnids (27 species. The numerical density of protozoans was high over the whole area, with annual averages between 8.2 × 103 cells m-3 and 51.4 × 103 cells m-3.Spring was the most productive season for protozoans, but several distinct peaks were observed during the year at the sampling sites. The protozoangroups showed clearly different spatial patterns in both composition and abundance: whereas amoebozoans and non-tintinnid ciliates were dominant in themore polluted areas (sites IV and V, tintinnids dominated in the less polluted areas (sites, I, II and III. Several pollution indicators wererecorded: amoebozoans - Centropyxis aculeata, Centropyxis sp., Cochliopodium sp.,Difflugia sp.; non-tintinnids - Bursaridium sp., Frontonia atra,Holophrya sp., Paramecium sp., Paramecium bursaria,Vasicola ciliata, Vorticella sp., Strombidium sp.; tintinnids- Favella ehrenbergii, Helicostomella subulata, Leprotintinnus nordgvisti,Tintinnopsis beroidea, Stenosemella ventricosa, Tintinnopsis campanula,T. cylindrica, T. lobiancoi, Eutintinnus lusus-undae.

  1. A 3-D velocity model for earthquake location from combined geological and geophysical data: a case study from the TABOO near fault observatory (Northern Apennines, Italy)

    Science.gov (United States)

    Latorre, Diana; Lupattelli, Andrea; Mirabella, Francesco; Trippetta, Fabio; Valoroso, Luisa; Lomax, Anthony; Di Stefano, Raffaele; Collettini, Cristiano; Chiaraluce, Lauro

    2014-05-01

    Accurate hypocenter location at the crustal scale strongly depends on our knowledge of the 3D velocity structure. The integration of geological and geophysical data, when available, should contribute to a reliable seismic velocity model in order to guarantee high quality earthquake locations as well as their consistency with the geological structure. Here we present a 3D, P- and S-wave velocity model of the Upper Tiber valley region (Northern Apennines) retrieved by combining an extremely robust dataset of surface and sub-surface geological data (seismic reflection profiles and boreholes), in situ and laboratory velocity measurements, and earthquake data. The study area is a portion of the Apennine belt undergoing active extension where a set of high-angle normal faults is detached on the Altotiberina low-angle normal fault (ATF). From 2010, this area hosts a scientific infrastructure (the Alto Tiberina Near Fault Observatory, TABOO; http://taboo.rm.ingv.it/), consisting of a dense array of multi-sensor stations, devoted to studying the earthquakes preparatory phase and the deformation processes along the ATF fault system. The proposed 3D velocity model is a layered model in which irregular shaped surfaces limit the boundaries between main lithological units. The model has been constructed by interpolating depth converted seismic horizons interpreted along 40 seismic reflection profiles (down to 4s two way travel times) that have been calibrated with 6 deep boreholes (down to 5 km depth) and constrained by detailed geological maps and structural surveys data. The layers of the model are characterized by similar rock types and seismic velocity properties. The P- and S-waves velocities for each layer have been derived from velocity measurements coming from both boreholes (sonic logs) and laboratory, where measurements have been performed on analogue natural samples increasing confining pressure in order to simulate crustal conditions. In order to test the 3D velocity

  2. In vitro solubility, dissolution and permeability studies combined with semi-mechanistic modeling to investigate the intestinal absorption of desvenlafaxine from an immediate- and extended release formulation

    DEFF Research Database (Denmark)

    Franek, F; Jarlfors, A; Larsen, F.

    2015-01-01

    Desvenlafaxine is a biopharmaceutics classification system (BCS) class 1 (high solubility, high permeability) and biopharmaceutical drug disposition classification system (BDDCS) class 3, (high solubility, poor metabolism; implying low permeability) compound. Thus the rate-limiting step for desve......Desvenlafaxine is a biopharmaceutics classification system (BCS) class 1 (high solubility, high permeability) and biopharmaceutical drug disposition classification system (BDDCS) class 3, (high solubility, poor metabolism; implying low permeability) compound. Thus the rate-limiting step...... for desvenlafaxine absorption (i.e. intestinal dissolution or permeation) is not fully clarified. The aim of this study was to investigate whether dissolution and/or intestinal permeability rate-limit desvenlafaxine absorption from an immediate-release formulation (IRF) and Pristiq®, an extended release formulation...... (ERF). Semi-mechanistic models of desvenlafaxine were built (using SimCyp®) by combining in vitro data on dissolution and permeation (mechanistic part of model) with clinical data (obtained from literature) on distribution and clearance (non-mechanistic part of model). The model predictions...

  3. Empirical study of travel mode forecasting improvement for the combined revealed preference/stated preference data–based discrete choice model

    Directory of Open Access Journals (Sweden)

    Yanfu Qiao

    2016-01-01

    Full Text Available The combined revealed preference/stated preference data–based discrete choice model has provided the actual choice-making restraints as well as reduced the prediction errors. But the random error variance of alternatives belonging to different data would impact its universality. In this article, we studied the traffic corridor between Chengdu and Longquan with the revealed preference/stated preference joint model, and the single stated preference data model separately predicted the choice probability of each mode. We found the revealed preference/stated preference joint model is universal only when there is a significant difference between the random error terms in different data. The single stated preference data would amplify the travelers’ preference and cause prediction error. We proposed a universal way that uses revealed preference data to modify the single stated preference data parameter estimation results to achieve the composite utility and reduce the prediction error. And the result suggests that prediction results are more reasonable based on the composite utility than the results based on the single stated preference data, especially forecasting the mode share of bus. The future metro line will be the main travel mode in this corridor, and 45% of passenger flow will transfer to the metro.

  4. Combining ocean numerical model and SAR imagery to investigate the occurrence of oil pollution, a case study for the Java Sea

    Science.gov (United States)

    Setiawan, A.; Putri, M. R.; Gade, M.; Pohlmann, T.; Mayer, B.

    2017-01-01

    IndoNACE is an abbreviation of Indo nesian Seas N umerical A ssessment of the C oastal E nvironment, a pilot study between Indonesia and Germany that combining analysis of oil spills from SAR images and numerical tracer studies from 3-D numerical model. Aim of this study is to understand the observed seasonal variations in marine oil pollution. Within this study, a visual inspection of all available SAR images is performed in order to generate maps of oil pollution occurrence in the Java Sea. Afterward, a set of numerical models is applied to trace back the origin of oil pollution. Our results showed that by analysing 706 ENVISAT ASAR images, the highest number of oil spills occurrence in the Java Sea was found during the transition monsoons, i.e. March to May and September to November. Assuming Marine Protected Area (MPA) of Seribu Islands as the end position of oil trajectory, we found that the origins of oil pollutions in that area were mostly from north and east.

  5. A time study of cancer genetic counselors using a genetic counselor-only patient care model versus a traditional combined genetic counselor plus medical geneticist care model.

    Science.gov (United States)

    Heald, Brandie; Gustafson, Shanna; Mester, Jessica; Arscott, Patricia; Lynch, Katherine; Moline, Jessica; Eng, Charis

    2013-09-01

    Analyses of time-based effort have determined that clinical genetic services are labor-intensive, although these data derive primarily from studying geneticists' efforts in the pediatric model. No studies have investigated the time and patient care activities of cancer genetic counselors (GCs) in traditional clinics with a medical geneticist (GC/MD) compared with genetic counselor-only (GCO) appointments. In this study, 6 GCs prospectively tracked time spent in patient care activities in both clinical settings. The authors found that overall, GCs' time spent per patient was lower for GCO versus GC/MD visits. No differences were seen in time spent on results disclosure, but differences were noted in case preparation, face-to-face, and follow-up times. Furthermore, no differences were seen in number of case preparation activities or topics covered during a session. These data suggest that GCO visits result in better use of GCs' time, without a trade-off in number of patient-related activities.

  6. Study of the Combined Effect of Ibuprofen and Cholesterol on the Microviscosity and Ordering of Model Lipid Membranes by Timeresolved Measurement of Fluorescence Anisotropy Decay

    Science.gov (United States)

    Yefimova, S. L.; Tkacheva, T. N.; Kasian, N. A.

    2017-05-01

    The timeresolved fluorescence anisotropy decay of perylene incorporated into the lipid Ladipalmitoylphosphatidylch oline (DPPC) membrane has been studied to evaluate the membranotropic action of the nonsteroidal antiinflammatory drug, ibuprofen, and the combined effect of ibuprofen and cholesterol. The rotation correlation times (φ) and limiting anisotropy (r∞ ) permit an independent estimation of the effects of these additives on the microviscosity and ordering of model lipid membranes in different phase states. Ibuprofen was shown to cause a significant decrease in the DPPC membrane microviscosity in the gel phase with hardly any effect on the liquidcrystal phase. However, in both phases, ibuprofen diminishes the ordering of the lipid hydrophobic chains. A marked additive effect is noted when ibuprofen is embedded in the liquid membrane enriched with cholesterol, which manifests itself in substantial fluidization and disordering or the liquid membrane by the action of the components on the lipid membrane. Ibuprofen in the liquidcrystal phase causes leveling of the fluidizing and ordering effects of cholesterol.

  7. The distribution of InCl sub x compounds in model polymeric LEDs A combined low and high-energy ion beam analysis study

    CERN Document Server

    Reijme, M A; Simons, D P L; Schok, M; Ijzendoorn, L J V; Brongersma, H H; De Voigt, M J A

    2002-01-01

    A combination of low- and high-energy ion beam analysis techniques was used to determine the distribution of indium chloride compounds in model polymeric light-emitting diodes (p-LEDs). Parts of polymeric LEDs (polydialkoxyphenylenevinylene (OC sub 1 C sub 1 sub 0 -PPV) on indium-tin-oxide (ITO) substrates) were exposed to a HCl/Ar flow to simulate the processes occurring during conversion of precursor PPVs and acid treatment of polymers. Samples with variable exposure times as well as pristine samples were studied with Rutherford backscattering spectrometry (RBS), low energy ion scattering (LEIS), X-ray photoelectron spectroscopy (XPS) and particle induced X-ray emission (PIXE). The RBS measurements show that after HCl exposure indium is distributed throughout the OC sub 1 C sub 1 sub 0 -PPV layer. LEIS and XPS measurements indicate that the indium and chlorine are present at the outermost surface of the OC sub 1 C sub 1 sub 0 -PPV layer. PIXE measurements in combination with the RBS data demonstrate that th...

  8. Modeling the efficacy of triplet antimicrobial combinations: yeast suppression by lauric arginate, cinnamic acid, and sodium benzoate or potassium sorbate as a case study.

    Science.gov (United States)

    Dai, Yumei; Normand, Mark D; Weiss, Jochen; Peleg, Micha

    2010-03-01

    The growth of four spoilage yeasts, Saccharomyces cerevisiae, Zygosaccharomyces bailii, Brettanomyces bruxellensis, and Brettanomyces naardenensis, was inhibited with three-agent (triplet) combinations of lauric arginate, cinnamic acid, and sodium benzoate or potassium sorbate. The inhibition efficacy was determined by monitoring the optical density of yeast cultures grown in microtiter plates for 7 days. The relationship between the optical density and the sodium benzoate and potassium sorbate concentrations followed a single-term exponential decay model. The critical effective concentration was defined as the concentration at which the optical density was 0.05, which became an efficacy criterion for the mixtures. Critical concentrations of sodium benzoate or potassium sorbate as a function of the lauric arginate and cinnamic acid concentrations were then fitted with an empirical model that mapped three-agent combinations of equal efficacy. The contours of this function are presented in tabulated form and as two- and three-dimensional plots. Triplet combinations were highly effective against all four spoilage yeasts at three practical pH levels, especially at pH 3.0. The triplet combinations were particularly effective for inhibiting growth of Z. bailii, and combinations containing potassium sorbate had synergistic activities. The equal efficacy concentration model also allowed tabulation of the cost of the various combinations of agents and identification of those most economically feasible.

  9. Combining SKU-level sales forecasts from models and experts

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); R. Legerstee (Rianne)

    2009-01-01

    textabstractWe study the performance of SKU-level sales forecasts which linearly combine statistical model forecasts and expert forecasts. Using a large and unique database containing model forecasts for monthly sales of various pharmaceutical products and forecasts given by about fifty experts, we

  10. Combined effects of porous hydroxyapatite and demineralized bone matrix on bone induction: in vitro and in vivo study using a nude rat model

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Hyup; Lee, Kyung-Mee; Baek, Hae-Ri; Jang, Soo-Jeong; Lee, Ji-Ho [Department of Orthopedic Surgery, Seoul National University School of Medicine, SMG-SNU Boramae Medical Center, Seoul 156-707 (Korea, Republic of); Ryu, Hyun-Seung, E-mail: spinelee@snu.ac.kr [Research and Development Center, CGBio Inc., Seong-Nam 462-120 (Korea, Republic of)

    2011-02-15

    Hydroxyapatite (HA) is an osteoconductive material used as a bone graft extender and demineralized bone matrix (DBM) has been used as a source of osteoinductive factors. A combination of DBM and HA is expected to create a composite with both osteoconductive and osteoinductive properties. This study examined the effect of a combination of DBM and HA on osteogenesis both in vitro and in vivo using an athymic nude rat abdominal muscle pouch model, and evaluated the possibility of HA as a carrier of DBM. Alkaline phosphatase (ALP) staining, ALP assay and measurements of the mRNA expression of ALP and Runx2 by RT-PCR were performed by transplanting human mesenchymal stem cells onto a plate. Five athymic nude rats each were assigned to one of two experimental groups (DBM/HA putty and only HA, i.e. 15 pouches per group). The muscle pouches were filled with DBM/HA putty or only HA. Radiographs were obtained at weeks 4 and 8, postoperatively. The animals were sacrificed at week 8 postoperatively and high resolution microCT was used to confirm the newly formed mineralized tissue. Each pouch was fixed, embedded, sectioned and processed for hematoxylin and eosin staining. The ALP value of the DBM/HA putty was higher than those of HA and control (p < 0.05, each). The expression of ALP mRNA appeared higher on the DBM/HA putty than on HA and control. MicroCT and histology examinations of the DBM/HA putty demonstrated the presence of newly generated mineralized tissues but there was no mineralized tissue in the HA cases. In conclusion, the DBM/HA putty indicated osteoblastic differentiation in vitro and showed ectopic mineralized tissue formation in the rat abdominal pouch model. These findings indicate that the DBM/HA putty can retain its oteoinductivity and HA can be used as a carrier of DBM.

  11. Modeling the acid-base properties of bacterial surfaces: A combined spectroscopic and potentiometric study of the gram-positive bacterium Bacillus subtilis.

    Science.gov (United States)

    Leone, Laura; Ferri, Diego; Manfredi, Carla; Persson, Per; Shchukarev, Andrei; Sjöberg, Staffan; Loring, John

    2007-09-15

    In this study, macroscopic and spectroscopic data were combined to develop a surface complexation model that describes the acid-base properties of Bacillus subtilis. The bacteria were freeze-dried and then resuspended in 0.1 M NaCl ionic medium. Macroscopic measurements included potentiometric acid-base titrations and electrophoretic mobility measurements. In addition, ATR-FTIR spectra of wet pastes from suspensions of Bacillus subtilis at different pH values were collected. The least-squares program MAGPIE was used to generate a surface complexation model that takes into account the presence of three acid-base sites on the surface: tripple bond COOH, tripple bond NH+, and tripple bond PO-, which were identified previously by XPS measurements. Both potentiometric titration data and ATR-FTIR spectra were used quantitatively, and electrostatic effects at the charged bacterial surface were accounted for using the constant capacitance model. The model was calculated using two different approaches: in the first one XPS data were used to constrain the ratio of the total concentrations of all three surface sites. The capacitance of the double layer, the total buffer capacity, and the deprotonation constants of the tripple bond NH+, tripple bond POH, and tripple bond COOH species were determined in the fit. A second approach is presented in which the ratio determined by XPS of the total concentrations of tripple bond NH+ to tripple bond PO- sites is relaxed. The total concentration of tripple bond PO- sites was determined in the fit, while the deprotonation constant for tripple bond POH was manually varied until the minimization led to a model which predicted an isoelectric point that resulted in consistency with electrophoretic mobility data. The model explains well the buffering capacity of Bacillus subtilis suspensions in a wide pH range (between pH=3 and pH=9) which is of considerable environmental interest. In particular, a similar quantitative use of the IR data

  12. Rigorous Kinetic Modeling, Optimization, and Operability Studies of a Modified Claus Unit for an Integrated Gasification Combined Cycle (IGCC) Power Plant with CO{sub 2} Capture

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Dustin; Bhattacharyya, Debangsu; Turton, Richard; Zitney, Stephen E

    2011-12-15

    The modified Claus process is one of the most common technologies for sulfur recovery from acid gas streams. Important design criteria for the Claus unit, when part of an Integrated Gasification Combined Cycle (IGCC) power plant, are the ability to destroy ammonia completely and the ability to recover sulfur thoroughly from a relatively low purity acid gas stream without sacrificing flame stability. Because of these criteria, modifications to the conventional process are often required, resulting in a modified Claus process. For the studies discussed here, these modifications include the use of a 95% pure oxygen stream as the oxidant, a split flow configuration, and the preheating of the feeds with the intermediate pressure steam generated in the waste heat boiler (WHB). In the future, for IGCC plants with CO{sub 2} capture, the Claus unit must satisfy emission standards without sacrificing the plant efficiency in the face of typical disturbances of an IGCC plant, such as rapid change in the feed flow rates due to load-following and wide changes in the feed composition because of changes in the coal feed to the gasifier. The Claus unit should be adequately designed and efficiently operated to satisfy these objectives. Even though the Claus process has been commercialized for decades, most papers concerned with the modeling of the Claus process treat the key reactions as equilibrium reactions. Such models are validated by manipulating the temperature approach to equilibrium for a set of steady-state operating data, but they are of limited use for dynamic studies. One of the objectives of this study is to develop a model that can be used for dynamic studies. In a Claus process, especially in the furnace and the WHB, many reactions may take place. In this work, a set of linearly independent reactions has been identified, and kinetic models of the furnace flame and anoxic zones, WHB, and catalytic reactors have been developed. To facilitate the modeling of the Claus

  13. Rigorous Kinetic Modeling and Optimization Study of a Modified Claus Unit for an Integrated Gasification Combined Cycle (IGCC) Power Plant with CO{sub 2} Capture

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Dustin; Bhattacharyya, Debangsu; Turton, Richard; Zitney, Stephen E.

    2012-02-08

    The modified Claus process is one of the most common technologies for sulfur recovery from acid gas streams. Important design criteria for the Claus unit, when part of an Integrated Gasification Combined Cycle (IGCC) power plant, are the ability to destroy ammonia completely and the ability to recover sulfur thoroughly from a relatively low purity acid gas stream without sacrificing flame stability. Because of these criteria, modifications to the conventional process are often required, resulting in a modified Claus process. For the studies discussed here, these modifications include the use of a 95% pure oxygen stream as the oxidant, a split flow configuration, and the preheating of the feeds with the intermediate pressure steam generated in the waste heat boiler (WHB). In the future, for IGCC plants with CO{sub 2} capture, the Claus unit must satisfy emission standards without sacrificing the plant efficiency in the face of typical disturbances of an IGCC plant, such as rapid change in the feed flow rates due to load-following and wide changes in the feed composition because of changes in the coal feed to the gasifier. The Claus unit should be adequately designed and efficiently operated to satisfy these objectives. Even though the Claus process has been commercialized for decades, most papers concerned with the modeling of the Claus process treat the key reactions as equilibrium reactions. Such models are validated by manipulating the temperature approach to equilibrium for a set of steady-state operating data, but they are of limited use for dynamic studies. One of the objectives of this study is to develop a model that can be used for dynamic studies. In a Claus process, especially in the furnace and the WHB, many reactions may take place. In this work, a set of linearly independent reactions has been identified, and kinetic models of the furnace flame and anoxic zones, WHB, and catalytic reactors have been developed. To facilitate the modeling of the Claus

  14. Forecasting China's natural gas consumption based on a combination model

    Institute of Scientific and Technical Information of China (English)

    Gang Xu; Weiguo Wang

    2010-01-01

    Ensuring a sufficient energy supply is essential to a country.Natural gas constitutes a vital part in energy supply and therefore forecasting natural gas consumption reliably and accurately is an essential part of a country's energy policy.Over the years,studies have shown that a combinative model gives better projected results compared to a single model.In this study,we used Polynomial Curve and Moving Average Combination Projection (PCMACP) model to estimate the future natural gas consumption in China from 2009 to 2015.The new proposed PCMACP model shows more reliable and accurate results:its Mean Absolute Percentage Error (MAPE) is less than those of any previous models within the investigated range.According to the PCMACP model,the average annual growth rate will increase for the next 7 years and the amount of natural gas consumption will reach 171600 million cubic meters in 2015 in China.

  15. A hydrogeological study of the confined aquifers below the Boom Clay in NE-Belgium: combining a piezometric analysis with groundwater modelling

    Science.gov (United States)

    Vandersteen, Katrijn; Gedeon, Matej

    2013-04-01

    For more than 35 years, SCKCEN has been investigating the possibility of high-level and/or long-lived radioactive waste disposal in the Boom Clay in north-eastern Belgium. This research, defined in the long term management programme for high-level and/or long-lived waste of ONDRAF/NIRAS, includes studying the regional hydrogeology of the aquifer systems surrounding the Boom Clay. In this context, a hydrogeological study of the confined aquifers below the Boom Clay was performed. To properly address the conceptual uncertainties related to the poorly characterized domain featuring large uncertainty in the forcing data, a combination of a piezometric data analysis and hydrogeological modelling was used. The study area represents the confined part of the groundwater system located stratigraphically below the Boom Clay in NE-Belgium. This so-called deep aquifer system includes, with increasing depth, parts of the Oligocene aquifer, the Bartoon aquitard system and the Ledo-Paniselian-Brusselian aquifer. Due to the considerable pumping from these aquifers in combination with a limited recharge to the deep aquifer system, a gradual decrease in groundwater levels has been observed in more than 30-year piezometric records. The analysis of the piezometry of the confined deep aquifer system allowed gaining more insight on the system response to the intensive pumping. Since the Oligocene aquifer has a significantly lower permeability compared to the Ledo-Paniselian-Brusselian aquifer, the Oligocene pumping triggers only local effects on groundwater levels. Hence, the regional effects (constant decrease of groundwater levels) in the Oligocene aquifer are presumably caused by pumping in the Ledo-Paniselian-Brusselian aquifer, whereby the hydraulically isolating Maldegem Formation (Bartoon aquitard) dampens these effects. The amount of this dampening is given by the spatial distribution of the hydraulic properties of the Maldegem Formation and/or its variable thickness. For the

  16. Preliminary study of CT in combination with MRI perfusion imaging to assess hemodynamic changes during angiogenesis in a rabbit model of lung cancer

    Directory of Open Access Journals (Sweden)

    Zhang Q

    2013-06-01

    Full Text Available Qiang Zhang,1 Baoqi Shi,1 Zhaoxin Liu,1 Mingmin Zhang,1 Weijing Zhang21Radiology Department, Baotou Cancer Hospital, Inner Mongolia Autonomous Region, 2Department of Mathematics, College of Science, Beijing Institute of Technology, Beijing, People's Republic of ChinaBackground: This study used CT (computed tomography and magnetic resonance imaging (MRI to identify correlations between perfusion parameters for squamous cell lung carcinoma and tumor angiogenesis in a rabbit model of VX2 lung cancer.Methods: VX2 tumors were implanted in the lungs of 35 New Zealand White rabbits. CT and MRI perfusion scanning were performed on days 14, 17, 21, 25, and 28 after tumor implantation. CT perfusion parameters were perfusion, peak enhanced increment, transit time peak, and blood volume, and MRI perfusion parameters were wash in rate, wash out rate, maximum enhancement rate, and transit time peak. CT and MRI perfusion parameters were obtained at the tumor rim, in the tumor tissue, and in the muscle tissue surrounding the tumor.Results: On CT perfusion imaging, t values for perfusion, peak enhanced increment, and blood volume (tumor rim versus muscle were 16.31, 11.79, and 5.21, respectively (P 0.05. On MRI perfusion imaging, t values for wash in rate, wash out rate, and maximum enhancement rate (tumor rim versus muscle were 18.14, 8.79, and 6.02, respectively (P 0.05.Conclusion: A combination of CT and MRI perfusion imaging demonstrated hemodynamic changes in a rabbit model of VX2 lung cancer, and provides a theoretical foundation for treatment of human squamous cell lung carcinoma.Keywords: perfusion imaging, rabbits, animal model, lung, squamous carcinoma cell

  17. In vitro solubility, dissolution and permeability studies combined with semi-mechanistic modeling to investigate the intestinal absorption of desvenlafaxine from an immediate- and extended release formulation.

    Science.gov (United States)

    Franek, F; Jarlfors, A; Larsen, F; Holm, P; Steffansen, B

    2015-09-18

    Desvenlafaxine is a biopharmaceutics classification system (BCS) class 1 (high solubility, high permeability) and biopharmaceutical drug disposition classification system (BDDCS) class 3, (high solubility, poor metabolism; implying low permeability) compound. Thus the rate-limiting step for desvenlafaxine absorption (i.e. intestinal dissolution or permeation) is not fully clarified. The aim of this study was to investigate whether dissolution and/or intestinal permeability rate-limit desvenlafaxine absorption from an immediate-release formulation (IRF) and Pristiq(®), an extended release formulation (ERF). Semi-mechanistic models of desvenlafaxine were built (using SimCyp(®)) by combining in vitro data on dissolution and permeation (mechanistic part of model) with clinical data (obtained from literature) on distribution and clearance (non-mechanistic part of model). The model predictions of desvenlafaxine pharmacokinetics after IRF and ERF administration were compared with published clinical data from 14 trials. Desvenlafaxine in vivo dissolution from the IRF and ERF was predicted from in vitro solubility studies and biorelevant dissolution studies (using the USP3 dissolution apparatus), respectively. Desvenlafaxine apparent permeability (Papp) at varying apical pH was investigated using the Caco-2 cell line and extrapolated to effective intestinal permeability (Peff) in human duodenum, jejunum, ileum and colon. Desvenlafaxine pKa-values and octanol-water partition coefficients (Do:w) were determined experimentally. Due to predicted rapid dissolution after IRF administration, desvenlafaxine was predicted to be available for permeation in the duodenum. Desvenlafaxine Do:w and Papp increased approximately 13-fold when increasing apical pH from 5.5 to 7.4. Desvenlafaxine Peff thus increased with pH down the small intestine. Consequently, desvenlafaxine absorption from an IRF appears rate-limited by low Peff in the upper small intestine, which "delays" the predicted

  18. Modelling the Factors that Affect Individuals' Utilisation of Online Learning Systems: An Empirical Study Combining the Task Technology Fit Model with the Theory of Planned Behaviour

    Science.gov (United States)

    Yu, Tai-Kuei; Yu, Tai-Yi

    2010-01-01

    Understanding learners' behaviour, perceptions and influence in terms of learner performance is crucial to predict the use of electronic learning systems. By integrating the task-technology fit (TTF) model and the theory of planned behaviour (TPB), this paper investigates the online learning utilisation of Taiwanese students. This paper provides a…

  19. Modelling the Factors that Affect Individuals' Utilisation of Online Learning Systems: An Empirical Study Combining the Task Technology Fit Model with the Theory of Planned Behaviour

    Science.gov (United States)

    Yu, Tai-Kuei; Yu, Tai-Yi

    2010-01-01

    Understanding learners' behaviour, perceptions and influence in terms of learner performance is crucial to predict the use of electronic learning systems. By integrating the task-technology fit (TTF) model and the theory of planned behaviour (TPB), this paper investigates the online learning utilisation of Taiwanese students. This paper provides a…

  20. Long-Term Effectiveness and Cost-Effectiveness of Metformin Combined with Liraglutide or Exenatide for Type 2 Diabetes Mellitus Based on the CORE Diabetes Model Study.

    Directory of Open Access Journals (Sweden)

    Xuesong Zhang

    Full Text Available Type 2 diabetes mellitus (T2DM is associated with β cell impairment. Agonists of the glucagon-like peptide 1 (GLP-1 receptor (such as liraglutide and exenatide can increase the number of pancreatic β cells and improve cell function. These drugs contribute to the long-term control of T2DM.To evaluate the cost-effectiveness of metformin combined with liraglutide or exenatide in Chinese patient with T2DM.Patients with T2DM from the Third Hospital of Hebei Medical University were treated with oral metformin combined with liraglutide (0.6 mg/day, could be increased by 0.6 mg weekly until 1.2 or 1.8 mg or exenatide (5 μg bid for four weeks, increased to 10 μg bid. The computer simulation model CORE was used to calculate the 30-year expected life expectancy, quality-adjusted life years (QALY, direct costs, HbA1c levels, body mass index (BMI, and the incidence of cardiovascular, renal, and ocular complications of T2DM. Patients were followed up for 52 weeks. Medication costs were calculated according to retail prices in China. A 3% annual discount was adopted in this study.The 30-year simulation showed that the total direct medical costs were lower using liraglutide compared to exenatide by 2130 RMB/QALY yearly, while the expected life expectancy and QALY were increased by 0.471 years and 0.388, respectively, using liraglutide with an incremental cost-effectiveness of -11,550 RMB/QALYs.Liraglutide 1.2 mg/day was superior to exenatide 10 μg bid with respect to cost-effectiveness in Chinese patients with T2DM.

  1. Multi-Model Combination techniques for Hydrological Forecasting: Application to Distributed Model Intercomparison Project Results

    Energy Technology Data Exchange (ETDEWEB)

    Ajami, N K; Duan, Q; Gao, X; Sorooshian, S

    2005-04-11

    This paper examines several multi-model combination techniques: the Simple Multi-model Average (SMA), the Multi-Model Super Ensemble (MMSE), Modified Multi-Model Super Ensemble (M3SE) and the Weighted Average Method (WAM). These model combination techniques were evaluated using the results from the Distributed Model Intercomparison Project (DMIP), an international project sponsored by the National Weather Service (NWS) Office of Hydrologic Development (OHD). All of the multi-model combination results were obtained using uncalibrated DMIP model outputs and were compared against the best uncalibrated as well as the best calibrated individual model results. The purpose of this study is to understand how different combination techniques affect the skill levels of the multi-model predictions. This study revealed that the multi-model predictions obtained from uncalibrated single model predictions are generally better than any single member model predictions, even the best calibrated single model predictions. Furthermore, more sophisticated multi-model combination techniques that incorporated bias correction steps work better than simple multi-model average predictions or multi-model predictions without bias correction.

  2. Multi-Model Combination Techniques for Hydrological Forecasting: Application to Distributed Model Intercomparison Project Results

    Energy Technology Data Exchange (ETDEWEB)

    Ajami, N; Duan, Q; Gao, X; Sorooshian, S

    2006-05-08

    This paper examines several multi-model combination techniques: the Simple Multimodel Average (SMA), the Multi-Model Super Ensemble (MMSE), Modified Multi-Model Super Ensemble (M3SE) and the Weighted Average Method (WAM). These model combination techniques were evaluated using the results from the Distributed Model Intercomparison Project (DMIP), an international project sponsored by the National Weather Service (NWS) Office of Hydrologic Development (OHD). All of the multi-model combination results were obtained using uncalibrated DMIP model outputs and were compared against the best uncalibrated as well as the best calibrated individual model results. The purpose of this study is to understand how different combination techniques affect the skill levels of the multi-model predictions. This study revealed that the multi-model predictions obtained from uncalibrated single model predictions are generally better than any single member model predictions, even the best calibrated single model predictions. Furthermore, more sophisticated multi-model combination techniques that incorporated bias correction steps work better than simple multi-model average predictions or multi-model predictions without bias correction.

  3. Development of a combined radiation and full thickness burn injury minipig model to study the effects of uncultured adipose-derived regenerative cell therapy in wound healing.

    Science.gov (United States)

    Foubert, Philippe; Doyle-Eisele, Melanie; Gonzalez, Andreina; Berard, Felipe; Weber, Waylon; Zafra, Diana; Alfonso, Zeni; Zhao, Sherry; Tenenhaus, Mayer; Fraser, John K

    2017-03-01

    To develop an approach that models the cutaneous healing that occurs in a patient with full thickness thermal burn injury complicated by total body radiation exposure sufficient to induce sub-lethal prodromal symptoms. An assessment of the effects of an autologous cell therapy on wound healing on thermal burn injury with concomitant radiation exposure was used to validate the utility of the model. Göttingen minipigs were subjected to a 1.2 Gy total body irradiation by exposure to a 6 MV X-ray linear accelerator followed by ∼10 cm(2) full thickness burns (pre-heated brass block with calibrated spring). Three days after injury, wounds were excised to the underlying fascia and each animal was randomized to receive treatment with autologous adipose-derived regenerative cells (ADRC) delivered by local or intravenous injection, or vehicle control. Blood counts were used to assess radiation-induced marrow suppression. All animals were followed using digital imaging to assess wound healing. Full-thickness biopsies were obtained at 7, 14, 21 and 30 days' post-treatment. Compared to animals receiving burn injury alone, significant transient neutropenia and thrombocytopenia were observed in irradiated subjects with average neutrophil nadir of 0.79 × 10(3)/μl (day 15) and platelet nadir of 60 × 10(3)/μl (day 12). Wound closure through a combination of contraction and epithelialization from the wound edges occurred over a period of approximately 28 days' post excision and treatment. Re-epithelialization was accelerated in wounds treated with ADRC (mean 3.5-fold increase at 2 weeks post-treatment relative to control). This acceleration was accompanied by an average 67% increase in blood vessel density and 30% increase in matrix (collagen) deposition. Similar results were observed when ADRC were injected either directly into the wound or by intravenous administration. Although preliminary, this study provides a reproducible minipig model of thermal burn

  4. TIME SERIES FORECASTING WITH MULTIPLE CANDIDATE MODELS: SELECTING OR COMBINING?

    Institute of Scientific and Technical Information of China (English)

    YU Lean; WANG Shouyang; K. K. Lai; Y.Nakamori

    2005-01-01

    Various mathematical models have been commonly used in time series analysis and forecasting. In these processes, academic researchers and business practitioners often come up against two important problems. One is whether to select an appropriate modeling approach for prediction purposes or to combine these different individual approaches into a single forecast for the different/dissimilar modeling approaches. Another is whether to select the best candidate model for forecasting or to mix the various candidate models with different parameters into a new forecast for the same/similar modeling approaches. In this study, we propose a set of computational procedures to solve the above two issues via two judgmental criteria. Meanwhile, in view of the problems presented in the literature, a novel modeling technique is also proposed to overcome the drawbacks of existing combined forecasting methods. To verify the efficiency and reliability of the proposed procedure and modeling technique, the simulations and real data examples are conducted in this study.The results obtained reveal that the proposed procedure and modeling technique can be used as a feasible solution for time series forecasting with multiple candidate models.

  5. Vitamin D for combination photodynamic therapy of skin cancer in individuals with vitamin D deficiency: Insights from a preclinical study in a mouse model of squamous cell carcinoma

    Science.gov (United States)

    Anand, Sanjay; Thomas, Erik; Hasan, Tayyaba; Maytin, Edward V.

    2016-03-01

    Combination photodynamic therapy (cPDT) in which vitamin D (VD) is given prior to aminolevulinate, a precursor (pro-drug) for protoporphyrin IX (PpIX), is an approach developed in our laboratory. We previously showed that 1α,25- dihydroxyvitamin D3 (calcitriol), given prior to PDT, enhances accumulation of PpIX and improves cell death post-PDT in a mouse skin cancer model. However, since calcitriol poses a risk for hypercalcemia, we replaced systemic calcitriol with oral cholecalciferol (D3), administered as a high (tenfold, "10K") diet over a ten-day period. Here, we ask whether VD deficiency might alter the response to cPDT. Nude mice were fed a VD-deficient diet for at least 4 weeks ("deficient"); controls were fed a normal 1,000 IU/kg diet ("1K"). Human A431 cells were implanted subcutaneously and mice were switched to the 10K diet or continued on their baseline diets (controls). In other experiments, mice received a human equivalent dose of 50,000 IU D3 by oral gavage, to simulate administration of a single, high-dose VD pill. At various times, tumors were harvested and serum was collected to measure levels of VD metabolic intermediates. A significant increase in PpIX levels and in the expression of differentiation and proliferation markers in tumor tissue was observed after VD supplementation of both the deficient and 1K mice. Further results describing mechanistic details of PpIX enhancement through alteration of heme- and VD-metabolic enzyme levels will be presented. Based on these results, a clinical study using oral vitamin D prior to PDT for human skin cancer should be performed.

  6. Combining ground-based microwave radiometer and the AROME convective scale model through 1DVAR retrievals in complex terrain: an Alpine valley case study

    Directory of Open Access Journals (Sweden)

    P. Martinet

    2017-09-01

    Full Text Available A RPG-HATPRO ground-based microwave radiometer (MWR was operated in a deep Alpine valley during the Passy-2015 field campaign. This experiment aims to investigate how stable boundary layers during wintertime conditions drive the accumulation of pollutants. In order to understand the atmospheric processes in the valley, MWRs continuously provide vertical profiles of temperature and humidity at a high time frequency, providing valuable information to follow the evolution of the boundary layer. A one-dimensional variational (1DVAR retrieval technique has been implemented during the field campaign to optimally combine an MWR and 1 h forecasts from the French convective scale model AROME. Retrievals were compared to radiosonde data launched at least every 3 h during two intensive observation periods (IOPs. An analysis of the AROME forecast errors during the IOPs has shown a large underestimation of the surface cooling during the strongest stable episode. MWR brightness temperatures were monitored against simulations from the radiative transfer model ARTS2 (Atmospheric Radiative Transfer Simulator and radiosonde launched during the field campaign. Large errors were observed for most transparent channels (i.e., 51–52 GHz affected by absorption model and calibration uncertainties while a good agreement was found for opaque channels (i.e., 54–58 GHz. Based on this monitoring, a bias correction of raw brightness temperature measurements was applied before the 1DVAR retrievals. 1DVAR retrievals were found to significantly improve the AROME forecasts up to 3 km but mainly below 1 km and to outperform usual statistical regressions above 1 km. With the present implementation, a root-mean-square error (RMSE of 1 K through all the atmospheric profile was obtained with values within 0.5 K below 500 m in clear-sky conditions. The use of lower elevation angles (up to 5° in the MWR scanning and the bias correction were found to improve the

  7. Combining ground-based microwave radiometer and the AROME convective scale model through 1DVAR retrievals in complex terrain: an Alpine valley case study

    Science.gov (United States)

    Martinet, Pauline; Cimini, Domenico; De Angelis, Francesco; Canut, Guylaine; Unger, Vinciane; Guillot, Remi; Tzanos, Diane; Paci, Alexandre

    2017-09-01

    A RPG-HATPRO ground-based microwave radiometer (MWR) was operated in a deep Alpine valley during the Passy-2015 field campaign. This experiment aims to investigate how stable boundary layers during wintertime conditions drive the accumulation of pollutants. In order to understand the atmospheric processes in the valley, MWRs continuously provide vertical profiles of temperature and humidity at a high time frequency, providing valuable information to follow the evolution of the boundary layer. A one-dimensional variational (1DVAR) retrieval technique has been implemented during the field campaign to optimally combine an MWR and 1 h forecasts from the French convective scale model AROME. Retrievals were compared to radiosonde data launched at least every 3 h during two intensive observation periods (IOPs). An analysis of the AROME forecast errors during the IOPs has shown a large underestimation of the surface cooling during the strongest stable episode. MWR brightness temperatures were monitored against simulations from the radiative transfer model ARTS2 (Atmospheric Radiative Transfer Simulator) and radiosonde launched during the field campaign. Large errors were observed for most transparent channels (i.e., 51-52 GHz) affected by absorption model and calibration uncertainties while a good agreement was found for opaque channels (i.e., 54-58 GHz). Based on this monitoring, a bias correction of raw brightness temperature measurements was applied before the 1DVAR retrievals. 1DVAR retrievals were found to significantly improve the AROME forecasts up to 3 km but mainly below 1 km and to outperform usual statistical regressions above 1 km. With the present implementation, a root-mean-square error (RMSE) of 1 K through all the atmospheric profile was obtained with values within 0.5 K below 500 m in clear-sky conditions. The use of lower elevation angles (up to 5°) in the MWR scanning and the bias correction were found to improve the retrievals below 1000 m. MWR

  8. Efficacy and tolerability studies evaluating a sleep aid and analgesic combination of naproxen sodium and diphenhydramine in the dental impaction pain model in subjects with induced transient insomnia.

    Science.gov (United States)

    Cooper, S; Laurora, I; Wang, Y; Venkataraman, P; An, R; Roth, T

    2015-10-01

    The aim of this study was to evaluate the efficacy and tolerability of novel combination naproxen sodium (NS) and diphenhydramine (DPH) in subjects with postoperative dental pain along with transient insomnia induced by 5 h sleep phase advance. The present studies aimed to demonstrate the added benefit and optimal dosages of the combination product over individual ingredients alone in improving sleep and pain. Each of the two studies was a two-centre, randomised, double-blind and double-dummy trial. In the first study, subjects were randomised into one of the following treatment arms: NS 440 mg/DPH 50 mg, NS 220 mg/DPH 50 mg, NS 440 mg or DPH 50 mg. In the second study, subjects received either NS 440 mg/DPH 25 mg, NS 440 mg or DPH 50 mg. The co-primary end-points in both studies were wake time after sleep onset (WASO) and sleep latency (SL) measured by actigraphy. Other secondary sleep and pain end-points were also assessed. The intent-to-treat population included 712 and 267 subjects from studies one and two, respectively. In the first study, only the NS 440 mg/DPH 50 mg combination showed significant improvements in both WASO vs. NS alone (-70.3 min p = 0.0002) and SL vs. DPH alone (25.50 and 41.50 min respectively, p sleep latency vs. DPH 50 mg and sleep maintenance (WASO) vs. NS 440 mg. There were no serious or unexpected adverse events reported in either study. NCT01280591 (study 1); NCT01495858 (study 2). © 2015 The Authors. International Journal of Clinical Practice Published by John Wiley & Sons Ltd.

  9. Transarterial embolization combined with RNA interference targeting hypoxia-inducible factor-1α for hepatocellular carcinoma: a preliminary study of rat model.

    Science.gov (United States)

    Ni, Jia-Yan; Xu, Lin-Feng; Wang, Wei-Dong; Huang, Qiao-Sheng; Sun, Hong-Liang; Chen, Yao-Ting

    2017-02-01

    To study whether transarterial embolization (TAE) with RNA interference (RNAi) targeting hypoxia-inducible factor-1α (HIF-1α) can improve efficacy of TAE in treating hepatocellular carcinoma (HCC). CBRH-7919 rat hepatoma cell line was used and HCC models of rats were constructed. The siRNA transfection compound was made by mixing specific siRNA and Lipofectamine 2000™. Delivery and transfection of siRNA were administered by injecting iodized oil emulsion (diluted lipiodol and siRNA) via hepatic artery. The expression levels of mRNA and protein were detected using the real-time reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry and western blotting assays, respectively. In vitro experiment, the specific HIF-1α-siRNA was proved to inhibit expression levels of HIF-1α and vascular endothelial growth factor (VEGF) effectively. In animal study, real-time RT-PCR assay showed the average relative mRNA expressions of HIF-1α were 0.31 ± 0.01, 0.65 ± 0.03, 0.46 ± 0.005, and 1.00 ± 0.00 in TAE + siRNA, siRNA, TAE, and control groups, respectively. Western blotting assay showed the average relative protein expressions of HIF-1α were 0.13 ± 0.02, 0.87 ± 0.02, 0.39 ± 0.02, and 1.02 ± 0.01 in TAE + siRNA, siRNA, TAE, and control groups, respectively. Compared with control, TAE, and siRNA groups, TAE + siRNA can significantly inhibit protein expressions of HIF-1α and VEGF (P HIF-1α < 0.001; P VEGF < 0.001). Overall survival of rats underwent TAE + siRNA was significantly longer than that of rats treated with TAE monotherapy (P = 0.001). This animal study showed TAE combined with HIF-1α-RNAi could significantly improve efficacy of TAE in treating HCC by inhibiting expressions of HIF-1α and VEGF after TAE treatment.

  10. Effects of Combined Hands-on Laboratory and Computer Modeling on Student Learning of Gas Laws: A Quasi-Experimental Study

    Science.gov (United States)

    Liu, Xiufeng

    2006-01-01

    Based on current theories of chemistry learning, this study intends to test a hypothesis that computer modeling enhanced hands-on chemistry laboratories are more effective than hands-on laboratories or computer modeling laboratories alone in facilitating high school students' understanding of chemistry concepts. Thirty-three high school chemistry…

  11. Model-based efficiency evaluation of combine harvester traction drives

    Directory of Open Access Journals (Sweden)

    Steffen Häberle

    2015-08-01

    Full Text Available As part of the research the drive train of the combine harvesters is investigated in detail. The focus on load and power distribution, energy consumption and usage distribution are explicitly explored on two test machines. Based on the lessons learned during field operations, model-based studies of energy saving potential in the traction train of combine harvesters can now be quantified. Beyond that the virtual machine trial provides an opportunity to compare innovative drivetrain architectures and control solutions under reproducible conditions. As a result, an evaluation method is presented and generically used to draw comparisons under local representative operating conditions.

  12. A combination of pharmacophore modeling, atom-based 3D-QSAR, molecular docking and molecular dynamics simulation studies on PDE4 enzyme inhibitors.

    Science.gov (United States)

    Tripuraneni, Naga Srinivas; Azam, Mohammed Afzal

    2016-11-01

    Phosphodiesterases 4 enzyme is an attractive target for the design of anti-inflammatory and bronchodilator agents. In the present study, pharmacophore and atom-based 3D-QSAR studies were carried out for pyrazolopyridine and quinoline derivatives using Schrödinger suite 2014-3. A four-point pharmacophore model was developed using 74 molecules having pIC50 ranging from 10.1 to 4.5. The best four feature model consists of one hydrogen bond acceptor, two aromatic rings, and one hydrophobic group. The pharmacophore hypothesis yielded a statistically significant 3D-QSAR model, with a high correlation coefficient (R(2 )= .9949), cross validation coefficient (Q(2 )= .7291), and Pearson-r (.9107) at six component partial least square factor. The external validation indicated that our QSAR model possessed high predictive power with R(2) value of .88. The generated model was further validated by enrichment studies using the decoy test. Molecular docking, free energy calculation, and molecular dynamics (MD) simulation studies have been performed to explore the putative binding modes of these ligands. A 10-ns MD simulation confirmed the docking results of both stability of the 1XMU-ligand complex and the presumed active conformation. Outcomes of the present study provide insight in designing novel molecules with better PDE4 inhibitory activity.

  13. Combined Injury Modeling: Radiation and Burn Workshop Report

    Science.gov (United States)

    2010-10-01

    when radiation exposure is combined with burn. For instance, in the Chernobyl accident, hepatic encephalopathy was a major cause of death in patients...for radiation injury that block apoptosis and have demonstrated increased survival in animal models (Whitnall and Pellmar 2007). Cell loss also... Animal studies are needed to resolve this information gap. However, Institutional Animal Care and Use Committee (IACUC) approval for these types

  14. Deterministic combination of numerical and physical coastal wave models

    DEFF Research Database (Denmark)

    Zhang, H.W.; Schäffer, Hemming Andreas; Jakobsen, K.P.

    2007-01-01

    A deterministic combination of numerical and physical models for coastal waves is developed. In the combined model, a Boussinesq model MIKE 21 BW is applied for the numerical wave computations. A piston-type 2D or 3D wavemaker and the associated control system with active wave absorption provides...

  15. Combined 3D-QSAR modeling and molecular docking study on multi-acting quinazoline derivatives as HER2 kinase inhibitors.

    Science.gov (United States)

    Mirzaie, Sako; Monajjemi, Majid; Hakhamaneshi, Mohammad Saeed; Fathi, Fardin; Jamalan, Mostafa

    2013-01-01

    A series of new quinazoline derivatives has been recently reported as potent multi-acting histone deacetylase (HDAC), epidermal growth factor receptor (EGFR), and human epidermal growth factor receptor 2 (HER2) inhibitors. HER2 is one of the major targets for the treatment of breast cancer and other carcinomas. Three-dimensional structure-activity relationship (3D-QSAR) is a well-known technique, which is used to drug design and development. This technique is used for quantitatively predicting the interaction between a molecule and the active site of a specific target. For each 3D-QSAR study, a three-dimensional model is created from a large curve fit to find a fitting between computational descriptors and biological activity. This model could be used as a predictive tool in drug design. The best model has the highest correlation between theoretical and experimental data. Self-Organizing Molecular Field Analysis (SOMFA), a grid-based and alignment-dependent 3D-QSAR method, is employed to study the correlation between the molecular properties and HER2 inhibitory potency of the quinazoline derivatives. Before presentation of inhibitor structures to SOMFA study, conformation of inhibitors was determined by AutoDock4, HyperChem and AutoDock Vina, separately. Overall, six independent models were produced and evaluated by the statistical partial least square (PLS) analysis. Among the several generated 3D-QSARs, the best model was selected on the basis of its statistical significance and predictive potential. The model derived from the superposition of docked conformation with AutoDock Vina with reasonable cross-validated q(2) (0.767), non cross-validated r(2) (0.815) and F-test (97.22) values showed a desirable predictive capability. Analysis of SOMFA model could provide some useful information in the design of novel HER2 kinase inhibitors with better spectrum of activity.

  16. An Analytical Tire Model with Flexible Carcass for Combined Slips

    Directory of Open Access Journals (Sweden)

    Nan Xu

    2014-01-01

    Full Text Available The tire mechanical characteristics under combined cornering and braking/driving situations have significant effects on vehicle directional controls. The objective of this paper is to present an analytical tire model with flexible carcass for combined slip situations, which can describe tire behavior well and can also be used for studying vehicle dynamics. The tire forces and moments come mainly from the shear stress and sliding friction at the tread-road interface. In order to describe complicated tire characteristics and tire-road friction, some key factors are considered in this model: arbitrary pressure distribution; translational, bending, and twisting compliance of the carcass; dynamic friction coefficient; anisotropic stiffness properties. The analytical tire model can describe tire forces and moments accurately under combined slip conditions. Some important properties induced by flexible carcass can also be reflected. The structural parameters of a tire can be identified from tire measurements and the computational results using the analytical model show good agreement with test data.

  17. A combined frequency modulation dynamic force microscopy (FM-DFM) and scanning tunneling microscopy (STM) study of a SiO{sub 2}/Ru(0001) model system

    Energy Technology Data Exchange (ETDEWEB)

    Buechner, Christin; Lichtenstein, Leonid; Heinke, Lars; Heyde, Markus; Freund, Hans-Joachim [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany)

    2011-07-01

    Silica based support materials play an important role in catalysis. A stable and well characterized crystalline silica film can act as a model system for bulk silica and help us to understand silica's properties in detail. In order to examine catalytically relevant processes on such model surfaces, a thorough investigation of defect sites of any form is eminent. Recently, a double-layer silica film could be prepared on Ru(0001). Here we used a combined frequency modulation dynamic force microscope (FM-DFM) and scanning tunneling microscope (STM) under low temperature and ultra-high vacuum conditions to unveil the thin film's structural and electronic surface properties. Atomically resolved images of the crystalline silica film grown on Ru(0001) are presented. Structural elements of the pristine film, as well as its defects, are highlighted. Based on atomic resolution FM-DFM and STM images a direct comparison with density functional theory calculation can be made. Theory as well as experiment favor a hexagonal honeycomb structure of the film. Spectroscopy measurements, i.e. scanning tunneling spectroscopy (STS) and Kelvin probe force microscopy (KPFM), provide first insights into electronic properties of the system.

  18. Combating Combination of Hypertension and Diabetes in Different Rat Models

    Directory of Open Access Journals (Sweden)

    Talma Rosenthal

    2010-03-01

    Full Text Available Rat experimental models are used extensively for studying physiological mechanisms and treatments of hypertension and diabetes co-existence. Each one of these conditions is a major risk factor for cardiovascular disease (CVD, and the combination of the two conditions is a potent enhancer of CVD. Five major animal models that advanced our understanding of the mechanisms and therapeutic approaches in humans are discussed in this review: Zucker, Goto-Kakizaki, SHROB, SHR/NDmcr-cp and Cohen Rosenthal diabetic hypertensive (CRDH rats. The use of various drugs, such as angiotensin-converting enzyme (ACE inhibitors (ACEIs, various angiotensin receptor blockers (ARBs, and calcium channel blockers (CCBs, to combat the effects of concomitant pathologies on the combination of diabetes and hypertension, as well as the non-pharmacological approach are reviewed in detail for each rat model. Results from experiments on these models indicate that classical factors contributing to the pathology of hypertension and diabetes combination—Including hypertension, hyperglycemia, hyperinsulinemia and hyperlipidemia—can now be treated, although these treatments do not completely prevent renal complications. Animal studies have focused on several mechanisms involved in hypertension/diabetes that remain to be translated into clinical medicine, including hypoxia, oxidative stress, and advanced glycation. Several target molecules have been identified that need to be incorporated into a treatment modality. The challenge continues to be the identification and interpretation of the clinical evidence from the animal models and their application to human treatment.

  19. Anatomical evaluation of CT-MRI combined femoral model

    Directory of Open Access Journals (Sweden)

    Kim Gyu-Ha

    2008-01-01

    Full Text Available Abstract Background Both CT and MRI are complementary to each other in that CT can produce a distinct contour of bones, and MRI can show the shape of both ligaments and bones. It will be ideal to build a CT-MRI combined model to take advantage of complementary information of each modality. This study evaluated the accuracy of the combined femoral model in terms of anatomical inspection. Methods Six normal porcine femora (180 ± 10 days, 3 lefts and 3 rights with ball markers were scanned by CT and MRI. The 3D/3D registration was performed by two methods, i.e. the landmark-based 3 points-to-3 points and the surface matching using the iterative closest point (ICP algorithm. The matching accuracy of the combined model was evaluated with statistical global deviation and locally measure anatomical contour-based deviation. Statistical analysis to assess any significant difference between accuracies of those two methods was performed using univariate repeated measures ANOVA with the Turkey post hoc test. Results This study revealed that the local 2D contour-based measurement of matching deviation was 0.5 ± 0.3 mm in the femoral condyle, and in the middle femoral shaft. The global 3D contour matching deviation of the landmark-based matching was 1.1 ± 0.3 mm, but local 2D contour deviation through anatomical inspection was much larger as much as 3.0 ± 1.8 mm. Conclusion Even with human-factor derived errors accumulated from segmentation of MRI images, and limited image quality, the matching accuracy of CT-&-MRI combined 3D models was 0.5 ± 0.3 mm in terms of local anatomical inspection.

  20. A designed screening study with prespecified combinations of factor settings

    Energy Technology Data Exchange (ETDEWEB)

    Anderson-cook, Christine M [Los Alamos National Laboratory; Robinson, Timothy J [U. WYOMING

    2009-01-01

    In many applications, the experimenter has limited options about what factor combinations can be chosen for a designed study. Consider a screening study for a production process involving five input factors whose levels have been previously established. The goal of the study is to understand the effect of each factor on the response, a variable that is expensive to measure and results in destruction of the part. From an inventory of available parts with known factor values, we wish to identify a best collection of factor combinations with which to estimate the factor effects. Though the observational nature of the study cannot establish a causal relationship involving the response and the factors, the study can increase understanding of the underlying process. The study can also help determine where investment should be made to control input factors during production that will maximally influence the response. Because the factor combinations are observational, the chosen model matrix will be nonorthogonal and will not allow independent estimation of factor effects. In this manuscript we borrow principles from design of experiments to suggest an 'optimal' selection of factor combinations. Specifically, we consider precision of model parameter estimates, the issue of replication, and abilities to detect lack of fit and to estimate two-factor interactions. Through an example, we present strategies for selecting a subset of factor combinations that simultaneously balance multiple objectives, conduct a limited sensitivity analysis, and provide practical guidance for implementing our techniques across a variety of quality engineering disciplines.

  1. A Combined In Vitro Imaging and Multi-Scale Modeling System for Studying the Role of Cell Matrix Interactions in Cutaneous Wound Healing.

    Science.gov (United States)

    De Jesus, Aribet M; Aghvami, Maziar; Sander, Edward A

    2016-01-01

    Many cell types remodel the extracellular matrix of the tissues they inhabit in response to a wide range of environmental stimuli, including mechanical cues. Such is the case in dermal wound healing, where fibroblast migrate into and remodel the provisional fibrin matrix in a complex manner that depends in part on the local mechanical environment and the evolving multi-scale mechanical interactions of the system. In this study, we report on the development of an image-based multi-scale mechanical model that predicts the short-term (24 hours), structural reorganization of a fibrin gel by fibroblasts. These predictive models are based on an in vitro experimental system where clusters of fibroblasts (i.e., explants) were spatially arranged into a triangular geometry onto the surface of fibrin gels that were subjected to either Fixed or Free in-plane mechanical constraints. Experimentally, regional differences in short-term structural remodeling and cell migration were observed for the two gel boundary conditions. A pilot experiment indicated that these small differences in the short-term remodeling of the fibrin gel translate into substantial differences in long-term (4 weeks) remodeling, particularly in terms of collagen production. The multi-scale models were able to predict some regional differences in remodeling and qualitatively similar reorganization patterns for the two boundary conditions. However, other aspects of the model, such as the magnitudes and rates of deformation of gel, did not match the experiments. These discrepancies between model and experiment provide fertile ground for challenging model assumptions and devising new experiments to enhance our understanding of how this multi-scale system functions. These efforts will ultimately improve the predictions of the remodeling process, particularly as it relates to dermal wound healing and the reduction of patient scarring. Such models could be used to recommend patient-specific mechanical

  2. A Combined In Vitro Imaging and Multi-Scale Modeling System for Studying the Role of Cell Matrix Interactions in Cutaneous Wound Healing.

    Directory of Open Access Journals (Sweden)

    Aribet M De Jesus

    Full Text Available Many cell types remodel the extracellular matrix of the tissues they inhabit in response to a wide range of environmental stimuli, including mechanical cues. Such is the case in dermal wound healing, where fibroblast migrate into and remodel the provisional fibrin matrix in a complex manner that depends in part on the local mechanical environment and the evolving multi-scale mechanical interactions of the system. In this study, we report on the development of an image-based multi-scale mechanical model that predicts the short-term (24 hours, structural reorganization of a fibrin gel by fibroblasts. These predictive models are based on an in vitro experimental system where clusters of fibroblasts (i.e., explants were spatially arranged into a triangular geometry onto the surface of fibrin gels that were subjected to either Fixed or Free in-plane mechanical constraints. Experimentally, regional differences in short-term structural remodeling and cell migration were observed for the two gel boundary conditions. A pilot experiment indicated that these small differences in the short-term remodeling of the fibrin gel translate into substantial differences in long-term (4 weeks remodeling, particularly in terms of collagen production. The multi-scale models were able to predict some regional differences in remodeling and qualitatively similar reorganization patterns for the two boundary conditions. However, other aspects of the model, such as the magnitudes and rates of deformation of gel, did not match the experiments. These discrepancies between model and experiment provide fertile ground for challenging model assumptions and devising new experiments to enhance our understanding of how this multi-scale system functions. These efforts will ultimately improve the predictions of the remodeling process, particularly as it relates to dermal wound healing and the reduction of patient scarring. Such models could be used to recommend patient

  3. The new RETScreen model for combined heat and power

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, U. [Natural Resources Canada, Varennes, PQ (Canada). CANMET Energy Diversification Laboratory

    2004-07-01

    RETScreen{sup R} is unique renewable energy awareness, decision-support and capacity building computer program designed to evaluate the energy performance, cost and viability of potential renewable energy technologies (RETs). The program has recently included a combined heat and power (CHP) model which includes the energy analysis for reciprocating engines, gas turbines, gas turbine combined cycle, fuel cells, steam turbines, microturbines, and geothermal energy. It was developed at the RETScreen International Renewable Energy Decision Support Centre at CANMET (Canada Centre for Mineral and Energy Technology). The tool consists of a standardised and integrated renewable energy analysis software that can be used worldwide to evaluate the energy production, life-cycle costs and greenhouse gas emission reductions for various types of RETs, and then compare them with those of conventional energy sources. Global climate change mitigation depends on widespread use of RETs around the world to meet the commitments of the Kyoto Protocol for cleaner air. The use of this computer program can help reduce the cost of pre-feasibility studies by providing information to help make better decisions about the technical and economic viability of potential projects. The CHP model considers landfill gas, biomass, bagasse, biodiesel, hydrogen, natural gas, petroleum, coal and municipal wastes. The model can be used for heating only, power only, cooling only, combined heat and power, single or multiple buildings, district energy or industrial processes. 22 figs.

  4. XPS of oxygen atoms on Ag(111) and Ag(110) surfaces: accurate study with SAC/SAC-CI combined with dipped adcluster model.

    Science.gov (United States)

    Ishikawa, Atsushi; Nakatsuji, Hiroshi

    2013-08-01

    O1s core-electron binding energies (CEBE) of the atomic oxygens on different Ag surfaces were investigated by the symmetry adapted cluster-configuration interaction (SAC-CI) method combined with the dipped adcluster model, in which the electron exchange between bulk metal and adsorbate is taken into account properly. Electrophilic and nucleophilic oxygens (O(elec) and O(nuc)) that might be important for olefin epoxidation in a low-oxygen coverage condition were focused here. We consider the O1s CEBE as a key property to distinguish the surface oxygen states, and series of calculation was carried out by the Hartree-Fock, Density functional theory, and SAC/SAC-CI methods. The experimental information and our SAC/SAC-CI results indicate that O(elec) is the atomic oxygen adsorbed on the fcc site of Ag(111) and that O(nuc) is the one on the reconstructed added-row site of Ag(110) and that one- and two-electron transfers occur, respectively, to the O(elec) and O(nuc) adclusters from the silver surface.

  5. Combined analysis of effective Higgs portal dark matter models

    CERN Document Server

    Beniwal, Ankit; Savage, Christopher; Scott, Pat; Weniger, Christoph; White, Martin; Williams, Anthony

    2015-01-01

    We combine and extend the analyses of effective scalar, vector, Majorana and Dirac fermion Higgs portal models of Dark Matter (DM), in which DM couples to the Standard Model (SM) Higgs boson via an operator of the form $\\mathcal{O}_{\\textrm{DM}}\\, H^\\dagger H$. For the fermion models, we take an admixture of scalar $\\overline{\\psi} \\psi$ and pseudoscalar $\\overline{\\psi} i\\gamma_5 \\psi$ interaction terms. For each model, we apply constraints on the parameter space based on the Planck measured DM relic density and the LHC limits on the Higgs invisible branching ratio. For the first time, we perform a consistent study of the indirect detection prospects for these models based on the WMAP7/Planck observations of the CMB, a combined analysis of 15 dwarf spheroidal galaxies by Fermi-LAT and the upcoming Cherenkov Telescope Array (CTA). We also perform a correct treatment of the momentum-dependent direct search cross-section that arises from the pseudoscalar interaction term in the fermionic DM theories. We find, i...

  6. Combined optimization model for sustainable energization strategy

    Science.gov (United States)

    Abtew, Mohammed Seid

    Access to energy is a foundation to establish a positive impact on multiple aspects of human development. Both developed and developing countries have a common concern of achieving a sustainable energy supply to fuel economic growth and improve the quality of life with minimal environmental impacts. The Least Developing Countries (LDCs), however, have different economic, social, and energy systems. Prevalence of power outage, lack of access to electricity, structural dissimilarity between rural and urban regions, and traditional fuel dominance for cooking and the resultant health and environmental hazards are some of the distinguishing characteristics of these nations. Most energy planning models have been designed for developed countries' socio-economic demographics and have missed the opportunity to address special features of the poor countries. An improved mixed-integer programming energy-source optimization model is developed to address limitations associated with using current energy optimization models for LDCs, tackle development of the sustainable energization strategies, and ensure diversification and risk management provisions in the selected energy mix. The Model predicted a shift from traditional fuels reliant and weather vulnerable energy source mix to a least cost and reliable modern clean energy sources portfolio, a climb on the energy ladder, and scored multifaceted economic, social, and environmental benefits. At the same time, it represented a transition strategy that evolves to increasingly cleaner energy technologies with growth as opposed to an expensive solution that leapfrogs immediately to the cleanest possible, overreaching technologies.

  7. Application of quality by design concept to develop a dual gradient elution stability-indicating method for cloxacillin forced degradation studies using combined mixture-process variable models.

    Science.gov (United States)

    Zhang, Xia; Hu, Changqin

    2017-09-08

    Penicillins are typical of complex ionic samples which likely contain large number of degradation-related impurities (DRIs) with different polarities and charge properties. It is often a challenge to develop selective and robust high performance liquid chromatography (HPLC) methods for the efficient separation of all DRIs. In this study, an analytical quality by design (AQbD) approach was proposed for stability-indicating method development of cloxacillin. The structures, retention and UV characteristics rules of penicillins and their impurities were summarized and served as useful prior knowledge. Through quality risk assessment and screen design, 3 critical process parameters (CPPs) were defined, including 2 mixture variables (MVs) and 1 process variable (PV). A combined mixture-process variable (MPV) design was conducted to evaluate the 3 CPPs simultaneously and a response surface methodology (RSM) was used to achieve the optimal experiment parameters. A dual gradient elution was performed to change buffer pH, mobile-phase type and strength simultaneously. The design spaces (DSs) was evaluated using Monte Carlo simulation to give their possibility of meeting the specifications of CQAs. A Plackett-Burman design was performed to test the robustness around the working points and to decide the normal operating ranges (NORs). Finally, validation was performed following International Conference on Harmonisation (ICH) guidelines. To our knowledge, this is the first study of using MPV design and dual gradient elution to develop HPLC methods and improve separations for complex ionic samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Transformations in oscillatory activity and evoked responses in primary somatosensory cortex in middle age: a combined computational neural modeling and MEG study.

    Science.gov (United States)

    Ziegler, David A; Pritchett, Dominique L; Hosseini-Varnamkhasti, Paymon; Corkin, Suzanne; Hämäläinen, Matti; Moore, Christopher I; Jones, Stephanie R

    2010-09-01

    Oscillatory brain rhythms and evoked responses are widely believed to impact cognition, but relatively little is known about how these measures are affected by healthy aging. The present study used MEG to examine age-related changes in spontaneous oscillations and tactile evoked responses in primary somatosensory cortex (SI) in healthy young (YA) and middle-aged (MA) adults. To make specific predictions about neurophysiological changes that mediate age-related MEG changes, we applied a biophysically realistic model of SI that accurately reproduces SI MEG mu rhythms, containing alpha (7-14 Hz) and beta (15-30 Hz) components, and evoked responses. Analyses of MEG data revealed a significant increase in prestimulus mu power in SI, driven predominately by greater mu-beta dominance, and a larger and delayed M70 peak in the SI evoked response in MA. Previous analysis with our computational model showed that the SI mu rhythm could be reproduced with a stochastic sequence of rhythmic approximately 10 Hz feedforward (FF) input to the granular layers of SI (representative of lemniscal thalamic input) followed nearly simultaneously by approximately 10 Hz feedback (FB) input to the supragranular layers (representative of input from high order cortical or non-specific thalamic sources) (Jones et al., 2009). In the present study, the model further predicted that the rhythmic FF and FB inputs become stronger with age. Further, the FB input is predicted to arrive more synchronously to SI on each cycle of the 10 Hz input in MA. The simulated neurophysiological changes are sufficient to account for the age-related differences in both prestimulus mu rhythms and evoked responses. Thus, the model predicts that a single set of neurophysiological changes intimately links these age-related changes in neural dynamics. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  9. An information theoretic approach for combining neural network process models.

    Science.gov (United States)

    Sridhar, D V.; Bartlett, E B.; Seagrave, R C.

    1999-07-01

    Typically neural network modelers in chemical engineering focus on identifying and using a single, hopefully optimal, neural network model. Using a single optimal model implicitly assumes that one neural network model can extract all the information available in a given data set and that the other candidate models are redundant. In general, there is no assurance that any individual model has extracted all relevant information from the data set. Recently, Wolpert (Neural Networks, 5(2), 241 (1992)) proposed the idea of stacked generalization to combine multiple models. Sridhar, Seagrave and Barlett (AIChE J., 42, 2529 (1996)) implemented the stacked generalization for neural network models by integrating multiple neural networks into an architecture known as stacked neural networks (SNNs). SNNs consist of a combination of the candidate neural networks and were shown to provide improved modeling of chemical processes. However, in Sridhar's work SNNs were limited to using a linear combination of artificial neural networks. While a linear combination is simple and easy to use, it can utilize only those model outputs that have a high linear correlation to the output. Models that are useful in a nonlinear sense are wasted if a linear combination is used. In this work we propose an information theoretic stacking (ITS) algorithm for combining neural network models. The ITS algorithm identifies and combines useful models regardless of the nature of their relationship to the actual output. The power of the ITS algorithm is demonstrated through three examples including application to a dynamic process modeling problem. The results obtained demonstrate that the SNNs developed using the ITS algorithm can achieve highly improved performance as compared to selecting and using a single hopefully optimal network or using SNNs based on a linear combination of neural networks.

  10. Three-dimensional model to capture the fate and transport of combined sewer overflow discharges: A case study in the Chicago Area Waterway System.

    Science.gov (United States)

    Quijano, Juan C; Zhu, Zhenduo; Morales, Viviana; Landry, Blake J; Garcia, Marcelo H

    2017-01-15

    We used a numerical model to analyze the impact of combined sewer overflows (CSOs) in the hydrodynamics and water quality of the Chicago Area Waterway System (CAWS). We coupled the Environmental Fluid Dynamics Code (EFDC) with the Water Quality Analysis Simulation Program (WASP) to perform three-dimensional simulations of the hydrodynamics and water quality in CAWS. The analysis was performed for two different storms: (i) May 6, 2009 representing a 6-hour duration 4-month return period, and (ii) September 12, 2008 representing a 48-hour duration 100-year return period. Results from the simulations show distinct differences between the two storms. During the May 2009 storm there was only one major CSO pumping event with negligible impact on the water quality of CAWS. During the September 2008 storm there were several CSOs that impacted the hydrodynamics and water quality of CAWS. In particular, CSOs during the September 2008 event induced a reversal flow in CAWS, with a plume of constituents that traveled in the opposite direction as water does under normal conditions. However, the simulation results show that CSOs events in CAWS take place during periods of high rainfall, thus the discharge of CSOs is significantly diluted along the CAWS. As a result, the concentrations of organic matter and inorganic nutrients observed at the downstream boundary in CAWS were significantly lower than those recorded at the CSOs outfalls and are within the limits established in the regulation for regular effluents. These results suggest that even during storms events with significant CSOs into the CAWS there is a significant dilution that reduce the impact in the water quality at the system boundaries.

  11. Combined microscopies study of the C-contamination induced by extreme-ultraviolet radiation: A surface-dependent secondary-electron-based model

    Science.gov (United States)

    Prezioso, S.; Donarelli, M.; Bisti, F.; Palladino, L.; Santucci, S.; Spadoni, S.; Avaro, L.; Liscio, A.; Palermo, V.; Ottaviano, L.

    2012-05-01

    SiO2 and Al2O3 surfaces exposed to periodically modulated extreme ultraviolet (EUV) light (λ = 46.9 nm) have been investigated at the μm scale by optical microscopy, scanning electron microscopy, scanning Auger microscopy, atomic force microscopy, and Kelvin probe force microscopy. The formation of a carbon contamination layer preserving the same periodical modulation of the EUV dose has been observed. The mechanisms of hydrocarbon molecules deposition have been studied with the help of correlation plots between the modulated Auger signal and the corresponding EUV dose. A surface-dependent secondary-electron-based model has been proposed.

  12. Combined microscopies study of the C-contamination induced by extreme-ultraviolet radiation: A surface-dependent secondary-electron-based model

    Energy Technology Data Exchange (ETDEWEB)

    Prezioso, S.; Donarelli, M.; Bisti, F.; Palladino, L.; Santucci, S.; Ottaviano, L. [Dip. di Fisica, Universita dell' Aquila, Via Vetoio, 67100 L' Aquila (Italy); Spadoni, S.; Avaro, L. [Micron, Process R and D, Via C. Olivetti 2, 20864 Agrate Brianza (Italy); Liscio, A.; Palermo, V. [CNR-ISOF, Via Gobetti 101, 40129 Bologna (Italy)

    2012-05-14

    SiO{sub 2} and Al{sub 2}O{sub 3} surfaces exposed to periodically modulated extreme ultraviolet (EUV) light ({lambda} = 46.9 nm) have been investigated at the {mu}m scale by optical microscopy, scanning electron microscopy, scanning Auger microscopy, atomic force microscopy, and Kelvin probe force microscopy. The formation of a carbon contamination layer preserving the same periodical modulation of the EUV dose has been observed. The mechanisms of hydrocarbon molecules deposition have been studied with the help of correlation plots between the modulated Auger signal and the corresponding EUV dose. A surface-dependent secondary-electron-based model has been proposed.

  13. RCCtrust: A Combined Trust Model for Electronic Community

    Institute of Scientific and Technical Information of China (English)

    Yu Zhang; Hua-Jun Chen; Xiao-Hong Jiang; Hao Sheng; Zhao-Hui Wu

    2009-01-01

    Previous trust models are mainly focused on reputational mechanism based on explicit trust ratings.However,the large amount of user-generated content and community context published on Web is often ignored.Without enough information,there are several problems with previous trust models:first,they cannot determine in which field one user trusts in another,so many models assume that trust exists in all fields.Second some models are not able to delineate the variation of trust SCales,therefore they regard each user trusts all his friends to the same extent.Third,since these models only focus on explicit trust ratings,so the trust matrix is very sparse.To Solve these problems,we present RCCtrust-a trust model which combines Reputation-,Content-and Context-based mechanisms to provide more accurate,fine-grained and efficient trust management for the electronic community.We extract trust-related information from user-generated content and community context from Web to extend reputation-based trust models. We introduce role-based and behavior-based reasoning functionalities to infer users'i nterests and category-specific trust relationships.Following the study in sociology, RCCtrust exploits similarities between pairs of users to depict difierentiated trust scales.The experimental results show that RCCtrust outperforin8 pure user similarity method and linear decay trust-aware technique in both accuracy and coverage for a Recommender System.

  14. ARMA-GM combined forewarning model for the quality control

    Institute of Scientific and Technical Information of China (English)

    Wang Xingyuan; Yang Xu

    2005-01-01

    Three forecasting models are set up: the auto-regressive moving average model, the grey forecasting model for the rate of qualified products Pt, and the grey forecasting model for time intervals of the quality catastrophes. Then a combined forewarning system for the quality of products is established, which contains three models, judgment rules and forewarning state illustration. Finally with an example of the practical production, this modeling system is proved fairly effective.

  15. Combined Waste Form Cost Trade Study

    Energy Technology Data Exchange (ETDEWEB)

    Dirk Gombert; Steve Piet; Timothy Trickel; Joe Carter; John Vienna; Bill Ebert; Gretchen Matthern

    2008-11-01

    A new generation of aqueous nuclear fuel reprocessing, now in development under the auspices of the DOE Office of Nuclear Energy (NE), separates fuel into several fractions, thereby partitioning the wastes into groups of common chemistry. This technology advance enables development of waste management strategies that were not conceivable with simple PUREX reprocessing. Conventional wisdom suggests minimizing high level waste (HLW) volume is desirable, but logical extrapolation of this concept suggests that at some point the cost of reducing volume further will reach a point of diminishing return and may cease to be cost-effective. This report summarizes an evaluation considering three groupings of wastes in terms of cost-benefit for the reprocessing system. Internationally, the typical waste form for HLW from the PUREX process is borosilicate glass containing waste elements as oxides. Unfortunately several fission products (primarily Mo and the noble metals Ru, Rh, Pd) have limited solubility in glass, yielding relatively low waste loading, producing more glass, and greater disposal costs. Advanced separations allow matching the waste form to waste stream chemistry, allowing the disposal system to achieve more optimum waste loading with improved performance. Metals can be segregated from oxides and each can be stabilized in forms to minimize the HLW volume for repository disposal. Thus, a more efficient waste management system making the most effective use of advanced waste forms and disposal design for each waste is enabled by advanced separations and how the waste streams are combined. This trade-study was designed to juxtapose a combined waste form baseline waste treatment scheme with two options and to evaluate the cost-benefit using available data from the conceptual design studies supported by DOE-NE.

  16. NR sulphur vulcanization: Interaction study between TBBS and DPG by means of a combined experimental rheometer and meta-model best fitting strategy

    Science.gov (United States)

    Milani, G.; Hanel, T.; Donetti, R.; Milani, F.

    2016-06-01

    The paper is aimed at studying the possible interaction between two different accelerators (DPG and TBBS) in the chemical kinetic of Natural Rubber (NR) vulcanized with sulphur. The same blend with several DPG and TBBS concentrations is deeply analyzed from an experimental point of view, varying the curing temperature in the range 150-180°C and obtaining rheometer curves with a step of 10°C. In order to study any possible interaction between the two accelerators -and eventually evaluating its engineering relevance-rheometer data are normalized by means of the well known Sun and Isayev normalization approach and two output parameters are assumed as meaningful to have an insight into the possible interaction, namely time at maximum torque and reversion percentage. Two different numerical meta-models, which belong to the family of the so-called response surfaces RS are compared. The first is linear against TBBS and DPG and therefore well reproduces no interaction between the accelerators, whereas the latter is a non-linear RS with bilinear term. Both RS are deduced from standard best fitting of experimental data available. It is found that, generally, there is a sort of interaction between TBBS and DPG, but that the error introduced making use of a linear model (no interaction) is generally lower than 10%, i.e. fully acceptable from an engineering standpoint.

  17. In-silico screening for DNA-dependent protein kinase (DNA-PK) inhibitors: Combined homology modeling, docking, molecular dynamic study followed by biological investigation.

    Science.gov (United States)

    Tarazi, Hamadeh; Saleh, Ekram; El-Awady, Raafat

    2016-10-01

    DNA-dependent protein kinase (DNA-PK) is a key enzyme in non-homologous DNA end joining (NHEJ) repair pathway. The targeted inhibition of such enzyme would furnish a valuable option for cancer treatment. In this study we report the development of validation of enzyme homology model, and the subsequent use of this model to perform docking-based virtual screening against a database of FDA-approved drugs. The nominated highest ranking hits (Praziquantel and Dutasteride) were subjected to biological investigation. Additionally, molecular dynamic study was carried-out for binding mode exploration. Results of the biological evaluation revealed that both compounds inhibit the DNA-PK enzymatic activity at relatively high concentration levels with an IC50 of 17.3μM for praziquantel and >20μM for dutasteride. Furthermore, both agents enhanced the anti-proliferative effects of doxorubicin and cisplatin on breast cancer (MCF7) and lung cancer (A549) cell lines. This result indicates that these two hits are good candidate as DNA-PK inhibitors and worth further structural modifications to enhance their enzyme inhibitory effects. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Mathematical Model of Asynchronous Motor with Embedded Combined Braking Device

    Directory of Open Access Journals (Sweden)

    V. Solencov

    2013-01-01

    Full Text Available The paper presents a conclusion of a mathematical model pertaining to asynchronous motor with embedded combined braking device on the basis of electromechanical brake and electromagnetic slip coupling. The mathematical model has been obtained in an orthogonal coordinate system a, b, which is fixed with respect to the asymmetric part of the asynchronous motor with embedded combined braking device. The model makes it possible to investigate transient processes in various asynchronous motors with embedded braking devices.

  19. Influence of ocean acidification on the organic complexation of iron and copper in Northwest European shelf seas; a combined observational and model study

    Directory of Open Access Journals (Sweden)

    Lizeth eAvendaño

    2016-04-01

    Full Text Available The pH of aqueous solutions is known to impact the chemical speciation of trace metals. In this study we conducted titrations of coastal seawaters with iron and copper at pH 7.91, 7.37 and 6.99 (expressed on the total pH scale. Changes in the concentration of iron and copper that complexed with the added ligands 1-nitroso-2-napthol and salicylaldoxime respectively were determined by adsorptive cathodic stripping voltammetry - competitive ligand equilibrium (AdCSV-CLE. Interpretation of the results, assuming complexation by a low concentration of discrete ligands, showed that conditional stability constants for iron complexes increased relative to inorganic iron complexation as pH decreased by approximately 1 log unit per pH unit, whilst those for copper did not change. No trend was observed for concentrations of iron and copper complexing ligands over the pH range examined. We also interpreted our titration data by describing chemical binding and polyelectrolytic effects using non-ideal competitive adsorption in Donnan-like gels (NICA-Donnan model in a proof of concept study. The NICA-Donnan approach allows for the development of a set of model parameters that are independent of ionic strength and pH, and thus calculation of metal speciation can be undertaken at ambient sample pH or the pH of a future, more acidic ocean. There is currently a lack of basic NICA-Donnan parameters applicable to marine dissolved organic matter (DOM so we assumed that the measured marine dissolved organic carbon could be characterized as terrestrial fulvic acids. Generic NICA-Donnan parameters were applied within the framework of the software program visual MINTEQ and the metal –added ligand concentrations [MeAL] calculated for the AdCSV-CLE conditions. For copper, calculated [MeAL] using the NICA-Donnan model for DOM were consistent with measured [MeAL], but for iron an inert fraction with kinetically inhibited dissolution was required in addition to the NICA

  20. A pilot study combining a GC-sensor device with a statistical model for the identification of bladder cancer from urine headspace.

    Directory of Open Access Journals (Sweden)

    Tanzeela Khalid

    Full Text Available There is a need to reduce the number of cystoscopies on patients with haematuria. Presently there are no reliable biomarkers to screen for bladder cancer. In this paper, we evaluate a new simple in-house fabricated, GC-sensor device in the diagnosis of bladder cancer based on volatiles. Sensor outputs from 98 urine samples were used to build and test diagnostic models. Samples were taken from 24 patients with transitional (urothelial cell carcinoma (age 27-91 years, median 71 years and 74 controls presenting with urological symptoms, but without a urological malignancy (age 29-86 years, median 64 years; results were analysed using two statistical approaches to assess the robustness of the methodology. A two-group linear discriminant analysis method using a total of 9 time points (which equates to 9 biomarkers correctly assigned 24/24 (100% of cancer cases and 70/74 (94.6% controls. Under leave-one-out cross-validation 23/24 (95.8% of cancer cases were correctly predicted with 69/74 (93.2% of controls. For partial least squares discriminant analysis, the correct leave-one-out cross-validation prediction values were 95.8% (cancer cases and 94.6% (controls. These data are an improvement on those reported by other groups studying headspace gases and also superior to current clinical techniques. This new device shows potential for the diagnosis of bladder cancer, but the data must be reproduced in a larger study.

  1. In-vivo luminescence model for the study of tumor regression and regrowth following combination regimens with differentiation-promoting agents and photodynamic therapy

    Science.gov (United States)

    Rollakanti, K.; Anand, S.; Maytin, E. V.

    2013-03-01

    Photodynamic therapy with aminolevulinic acid can be modified by pretreatment regimens with drugs such as 5- Fluorouracil (5-FU) or Vitamin D (calcitriol) that enhance accumulation of protoporphyrin IX (PpIX) within tumor tissue which presumably will enhance the therapeutic response to light. However, histological approaches for monitoring therapeutic responses are poorly suited for studying long term survival because large numbers of mice need to be sacrificed. To address this limitation, a non-invasive model to monitor tumor regression and regrowth has been established. Breast cancer cells, stably transfected with firefly luciferase (MDA-Luc cell line), are implanted orthotopically in nude mice (0.25 - 1 x 106 cells/site), and monitored 0-60 min after s.c. injection of luciferin, with Xenogen in-vivo imaging system. Luminescence is detectable at day 1 post-implantation. Tumors are suitable for experimentation on day 6, when daily injections of pretreatment agents (5-FU, 300 mg/kg; calcitriol, 1 μg/kg) begin. On day 9, ALA (75 mg/kg i.p.) is given for 4 hr, followed by illumination (633 nm, 100 J/cm2). Tumor luminescence post- PDT is monitored daily and compared with caliper measurements. Pretreatments (5-FU, calcitriol) by themselves do not inhibit luciferase expression, and all tumors grow at a similar rate during the pretreatment period. Results from in vivo survival experiments can be correlated to survival responses of MDA-Luc cells grown in monolayer cultures +/- PDT and +/- pretreatments, and additional mechanistic information (e.g. Ki67 and E-cadherin expression) obtained. In summary, this noninvasive model will permit testing of the therapeutic survival advantages of various pretreatments during cPDT.

  2. Combined forecasts from linear and nonlinear time series models

    NARCIS (Netherlands)

    N. Terui (Nobuhiko); H.K. van Dijk (Herman)

    1999-01-01

    textabstractCombined forecasts from a linear and a nonlinear model are investigated for time series with possibly nonlinear characteristics. The forecasts are combined by a constant coefficient regression method as well as a time varying method. The time varying method allows for a locally (non)line

  3. Direct model fitting to combine dithered ACS images

    CERN Document Server

    Mahmoudian, Haniyeh

    2013-01-01

    The information lost in images of undersampled CCD cameras can be recovered with the technique of `dithering'. A number of subexposures is taken with sub-pixel shifts in order to record structures on scales smaller than a pixel. The standard method to combine such exposures, `Drizzle', averages after reversing the displacements, including rotations and distortions. More sophisticated methods are available to produce, e.g., Nyquist sampled representations of band-limited inputs. While the combined images produced by these methods can be of high quality, their use as input for forward-modelling techniques in gravitational lensing is still not optimal, because the residual artefacts still affect the modelling results in unpredictable ways. In this paper we argue for an overall modelling approach that takes into account the dithering and the lensing without the intermediate product of a combined image. As one building block we introduce an alternative approach to combine dithered images by direct model fitting wi...

  4. Combined calibration and sensitivity analysis for a water quality model of the Biebrza River, Poland

    NARCIS (Netherlands)

    Perk, van der M.; Bierkens, M.F.P.

    1995-01-01

    A study was performed to quantify the error in results of a water quality model of the Biebrza River, Poland, due to uncertainties in calibrated model parameters. The procedure used in this study combines calibration and sensitivity analysis. Finally,the model was validated to test the model capabil

  5. Activity in the fronto-parietal network indicates numerical inductive reasoning beyond calculation: An fMRI study combined with a cognitive model.

    Science.gov (United States)

    Liang, Peipeng; Jia, Xiuqin; Taatgen, Niels A; Borst, Jelmer P; Li, Kuncheng

    2016-05-19

    Numerical inductive reasoning refers to the process of identifying and extrapolating the rule involved in numeric materials. It is associated with calculation, and shares the common activation of the fronto-parietal regions with calculation, which suggests that numerical inductive reasoning may correspond to a general calculation process. However, compared with calculation, rule identification is critical and unique to reasoning. Previous studies have established the central role of the fronto-parietal network for relational integration during rule identification in numerical inductive reasoning. The current question of interest is whether numerical inductive reasoning exclusively corresponds to calculation or operates beyond calculation, and whether it is possible to distinguish between them based on the activity pattern in the fronto-parietal network. To directly address this issue, three types of problems were created: numerical inductive reasoning, calculation, and perceptual judgment. Our results showed that the fronto-parietal network was more active in numerical inductive reasoning which requires more exchanges between intermediate representations and long-term declarative knowledge during rule identification. These results survived even after controlling for the covariates of response time and error rate. A computational cognitive model was developed using the cognitive architecture ACT-R to account for the behavioral results and brain activity in the fronto-parietal network.

  6. Tracing man's impact on groundwater dependent ecosystem using geochemical an isotope tools combined with 3D flow and transport modeling: case study from southern Poland

    Science.gov (United States)

    Zurek, Anna; Witczak, Stanislaw; Kania, Jaroslaw; Wachniew, Przemyslaw; Rozanski, Kazimierz; Dulinski, Marek; Jench, Olga

    2013-04-01

    Niepolomice Forest. There is a growing concern that continued exploitation of those wells may lead to lowering water table in the Niepolomice Forest area and, as a consequence, may trigger drastic changes in this unique ecosystem. A dedicated study was launched with the main aim to quantify the interaction between Niepolomice Forest, with the focus the Wielkie Bloto fen, and the underlying Bogucice Sands aquifer. The work was pursued along three major lines: (i) vertical profiling of the Wielkie Bloto fen aimed at characterizing chemical and isotope contrast in the shallow groundwater occupying the Quaternary cover in order to identify upward leakage of deeper groundwater in the investigated area, (ii) regular monitoring of flow rate, chemistry and environmental isotopes of the Dluga Woda stream draining the Wielkie Bloto fen, and (iii) 3D modeling of groundwater flow in the vicinity of the Wielkie Bloto fen focusing on quantifying the impact of the Wola Batorska well field on the regional groundwater flow patterns. The results of isotope and chemical analyses confirmed existence of upward seepage of groundwater from the Bogucice Sands aquifer in the area of Wielkie Bloto fen. Preliminary assessment of the water balance of Dluga Woda catchment indicates that the baseflow originating from groundwater seepage is equal approximately 16% of the annual precipitation. Results of 3D flow model applied to the study area indicate that prolonged operation of the well-field Wola Batorska at maximum capacity may lead to substantial lowering of water table in the Niepolomice Forest area and, as a consequence, endanger further existence of this unique GDTE. Acknowledgements. Partial financial support of this work through GENESIS project (http:/www.thegenesisproject.eu) funded by the European Commission 7FP contract 226536, and through statutory funds of the AGH University of Science and Technology (projects No.11.11.140.026 and 11.11.220.01) is kindly acknowledged.

  7. Combined first-principles and model Hamiltonian study of the perovskite series R MnO 3 (R =La ,Pr ,Nd ,Sm ,Eu , and Gd )

    Science.gov (United States)

    Kováčik, Roman; Murthy, Sowmya Sathyanarayana; Quiroga, Carmen E.; Ederer, Claude; Franchini, Cesare

    2016-02-01

    We merge advanced ab initio schemes (standard density functional theory, hybrid functionals, and the G W approximation) with model Hamiltonian approaches (tight-binding and Heisenberg Hamiltonian) to study the evolution of the electronic, magnetic, and dielectric properties of the manganite family R MnO3 (R =La,Pr,Nd,Sm,Eu, and Gd) . The link between first principles and tight binding is established by downfolding the physically relevant subset of 3 d bands with eg character by means of maximally localized Wannier functions (MLWFs) using the VASP2WANNIER90 interface. The MLWFs are then used to construct a general tight-binding Hamiltonian written as a sum of the kinetic term, the Hund's rule coupling, the JT coupling, and the electron-electron interaction. The dispersion of the tight-binding (TB) eg bands at all levels are found to match closely the MLWFs. We provide a complete set of TB parameters which can serve as guidance for the interpretation of future studies based on many-body Hamiltonian approaches. In particular, we find that the Hund's rule coupling strength, the Jahn-Teller coupling strength, and the Hubbard interaction parameter U remain nearly constant for all the members of the R MnO3 series, whereas the nearest-neighbor hopping amplitudes show a monotonic attenuation as expected from the trend of the tolerance factor. Magnetic exchange interactions, computed by mapping a large set of hybrid functional total energies onto an Heisenberg Hamiltonian, clarify the origin of the A-type magnetic ordering observed in the early rare-earth manganite series as arising from a net negative out-of-plane interaction energy. The obtained exchange parameters are used to estimate the Néel temperature by means of Monte Carlo simulations. The resulting data capture well the monotonic decrease of the ordering temperature down the series from R =La to Gd, in agreement with experiments. This trend correlates well with the modulation of structural properties, in

  8. Methodologies in the modeling of combined chemo-radiation treatments

    Science.gov (United States)

    Grassberger, C.; Paganetti, H.

    2016-11-01

    The variety of treatment options for cancer patients has increased significantly in recent years. Not only do we combine radiation with surgery and chemotherapy, new therapeutic approaches such as immunotherapy and targeted therapies are starting to play a bigger role. Physics has made significant contributions to radiation therapy treatment planning and delivery. In particular, treatment plan optimization using inverse planning techniques has improved dose conformity considerably. Furthermore, medical physics is often the driving force behind tumor control and normal tissue complication modeling. While treatment optimization and outcome modeling does focus mainly on the effects of radiation, treatment modalities such as chemotherapy are treated independently or are even neglected entirely. This review summarizes the published efforts to model combined modality treatments combining radiation and chemotherapy. These models will play an increasing role in optimizing cancer therapy not only from a radiation and drug dosage standpoint, but also in terms of spatial and temporal optimization of treatment schedules.

  9. On the combined gravity gradient modeling for applied geophysics

    CERN Document Server

    Veryaskin, Alexey

    2007-01-01

    Gravity gradiometry research and development has intensified in recent years to the extent that technologies providing a resolution of about 1 Eotvos per 1 sec average shall likely soon be available for multiple critical applications such as natural resources exploration, oil reservoir monitoring and defence establishment. Much of the content of this paper was composed a decade ago, and only minor modifications were required for the conclusions to be just as applicable today. In this paper we demonstrate how gravity gradient data can be modeled, and show some examples of how gravity gradient data can be combined in order to extract valuable information. In particular, this study demonstrates the importance of two gravity gradient components, Txz and Tyz which, when processed together, can provide more information on subsurface density contrasts than that derived solely from the vertical gravity gradient (Tzz).

  10. Applying theoretical premises of binary toxicity mathematical modeling to combined impacts of chemical plus physical agents (A case study of moderate subchronic exposures to fluoride and static magnetic field).

    Science.gov (United States)

    Katsnelson, B A; Tsepilov, N A; Panov, V G; Sutunkova, M P; Varaksin, A N; Gurvich, V B; Minigalieva, I A; Valamina, I E; Makeyev, O H; Meshtcheryakova, E Y

    2016-09-01

    Sodium fluoride solution was injected i.p. to rats at a dose equivalent to 0.1 LD50 three times a week up to 18 injections. Two thirds of these rats and of the sham-injected ones were exposed to the whole body impact of a 25 mT static magnetic field for 2 or 4 h a day, 5 times a week. For mathematical analysis of the effects they produced in combination, we used a response surface model. This analysis demonstrated that (like in combined toxicity) the combined adverse action of a chemical plus a physical agent was characterized by a diversity of types depending not only on particular effects these types were assessed for but on their level as well. From this point of view, the indices for which at least one statistically significant effect was observed could be classified as identifying (1) single-factor action; (2) additivity; (3) synergism; (4) antagonism (both subadditive unidirectional action and all variants of contradirectional action). Although the classes (2) and (3) taken together encompass a smaller part of the indices, the biological importance of some of them renders the combination of agents studied as posing a higher health risk than that associated with each them acting alone.

  11. The Combination Forecasting Model of Grain Production Based on Stepwise Regression Method and RBF Neural Network

    Directory of Open Access Journals (Sweden)

    Lihua Yang

    2015-04-01

    Full Text Available In order to improve the accuracy of grain production forecasting, this study proposed a new combination forecasting model, the model combined stepwise regression method with RBF neural network by assigning proper weights using inverse variance method. By comparing different criteria, the result indicates that the combination forecasting model is superior to other models. The performance of the models is measured using three types of error measurement, which are Mean Absolute Percentage Error (MAPE, Theil Inequality Coefficient (Theil IC and Root Mean Squared Error (RMSE. The model with smallest value of MAPE, Theil IC and RMSE stands out to be the best model in predicting the grain production. Based on the MAPE, Theil IC and RMSE evaluation criteria, the combination model can reduce the forecasting error and has high prediction accuracy in grain production forecasting, making the decision more scientific and rational.

  12. 3D discrete dislocation dynamics study of creep behavior in Ni-base single crystal superalloys by a combined dislocation climb and vacancy diffusion model

    Science.gov (United States)

    Gao, Siwen; Fivel, Marc; Ma, Anxin; Hartmaier, Alexander

    2017-05-01

    A three-dimensional (3D) discrete dislocation dynamics (DDD) creep model is developed to investigate creep behavior under uniaxial tensile stress along the crystallographic [001] direction in Ni-base single crystal superalloys, which takes explicitly account of dislocation glide, climb and vacancy diffusion, but neglects phase transformation like rafting of γ‧ precipitates. The vacancy diffusion model takes internal stresses by dislocations and mismatch strains into account and it is coupled to the dislocation dynamics model in a numerically efficient way. This model is helpful for understanding the fundamental creep mechanisms in superalloys and clarifying the effects of dislocation glide and climb on creep deformation. In cases where the precipitate cutting rarely occurs, e.g. due to the high anti-phase boundary energy and the lack of superdislocations, the dislocation glide in the γ matrix and the dislocation climb along the γ/γ‧ interface dominate plastic deformation. The simulation results show that a high temperature or a high stress both promote dislocation motion and multiplication, so as to cause a large creep strain. Dislocation climb accelerated by high temperature only produces a small plastic strain, but relaxes the hardening caused by the filling γ channels and lets dislocations further glide and multiply. The strongest variation of vacancy concentration occurs in the horizontal channels, where more mixed dislocations exit and tend to climb. The increasing internal stresses due to the increasing dislocation density are easily overcome by dislocations under a high external stress that leads to a long-term dislocation glide accompanied by multiplication.

  13. Identification of potential Gly/NMDA receptor antagonists by cheminformatics approach: a combination of pharmacophore modelling, virtual screening and molecular docking studies.

    Science.gov (United States)

    Ugale, V G; Bari, S B

    2016-01-01

    The Gly/NMDA receptor has become known as potential target for the management of neurodegenerative diseases. Discovery of Gly/NMDA antagonists has thus attracted much attention in recent years. In the present research, a cheminformatics approach has been used to determine structural requirements for Gly/NMDA antagonism and to identify potential antagonists. Here, 37 quinoxaline derivatives were selected to develop a significant pharmacophore model with good certainty. The selected model was validated by leave-one-out cross-validation, an external test set, decoy set and Y-randomization test. Applicability domain was verified by the standardization approach. The validated 3D-QSAR model was used to screen virtual hits from the ZINC database by pharmacophore mapping. Molecular docking was used for assessment of receptor-ligand binding modes and binding affinities. The GlideScore and molecular interactions with critical amino acids were considered as crucial features to identify final hits. Furthermore, hits were analysed for in silico pharmacokinetic parameters and Lipinski's rule of five, demonstrating their potential as drug-like candidates. The PubChem and SciFinder search tools were used to authenticate the novelty of leads retrieved. Finally, five different leads have been suggested as putative novel candidates for the exploration of potent Gly/NMDA receptor antagonists.

  14. 土壤重金属复合污染整体模型研究%Study on the Heavy Metal Combined Pollution Model in Soil

    Institute of Scientific and Technical Information of China (English)

    李莹; 王志忠; 肖国光

    2014-01-01

    在重金属迁移建模研究成果的基础上,考虑土壤对重金属的吸附特性,推导出土壤重金属复合污染物迁移转化整体模型。为求解该模型,分别引进 Langmuir 等温竞争吸附模型与土壤水分迁移模型。最后,以重金属 Zn 和 Cd 为例,数值模拟其在土壤中的垂向迁移过程,并利用 MATLAB 画出相关图形。%Based on the previous achievements and considering the soil’s adsorption characteristics of heavy metal,this paper proposed an overall migration model of heavy metal compound contaminants in soil.In order to solve the problem,the Langmuir isotherm competitive adsorption model and water migration model in soil were applied.Finally,an numerical simula-tion example of Zn and Cd was shown as heavy metal’s vertical migration in soil and displayed by MATLAB.

  15. On the relevance of the H2 + O reaction pathway for the surface formation of interstellar water - A combined experimental and modeling study

    CERN Document Server

    Lamberts, Thanja; Fedoseev, Gleb; Ioppolo, Sergio; Chuang, Ko-Ju; Linnartz, Harold

    2014-01-01

    The formation of interstellar water has been commonly accepted to occur on the surfaces of icy dust grains in dark molecular clouds at low temperatures (10-20 K), involving hydrogenation reactions of oxygen allotropes. As a result of the large abundances of molecular hydrogen and atomic oxygen in these regions, the reaction H2 + O has been proposed to contribute significantly to the formation of water as well. However, gas phase experiments and calculations, as well as solid-phase experimental work contradict this hypothesis. Here, we use precisely executed temperature programmed desorption (TPD) experiments in an ultra-high vacuum setup combined with kinetic Monte Carlo simulations to establish an upper limit of the water production starting from H2 and O. These reactants are brought together in a matrix of CO2 in a series of (control) experiments at different temperatures and with different isotopological compositions. The amount of water detected with the quadrupole mass spectrometer upon TPD is found to o...

  16. Mixed Models: Combining Incompatible Scalar Models in Any Spacetime Dimension

    CERN Document Server

    Klauder, John R

    2016-01-01

    Traditionally, covariant scalar field theory models are either super renormalizable, strictly renormalizable, or nonrenormalizable. The goal of `Mixed Models' is to make sense of sums of these distinct examples, e.g., $g\\varphi^4_3+g'\\varphi^6_3+g''\\varphi^8_3$, which includes an example of each kind for spacetime dimension $n=3$. We show how the several interactions such mixed models have may be turned on and off in any order without any difficulties. Analogous results are shown for $g\\varphi^4_n+g'\\varphi^{138}_n$, etc., for all $n\\ge3$. Different categories hold for $n=2$ such as, e.g., ${g P(\\varphi)_2+g' N\\!P}(\\varphi)_2$, that involve polynomial ($P$) and suitable nonpolynomial ($N\\!P$) interactions, etc. Analogous situations for $n=1$ (time alone) offer simple `toy' examples of how such mixed models may be constructed.

  17. High resolution gravity models combining terrestrial and satellite data

    Science.gov (United States)

    Rapp, Richard H.; Pavlis, Nikolaos K.; Wang, Yan M.

    1992-01-01

    Spherical harmonic expansions to degree 360 have been developed that combine satellite potential coefficient information, terrestrial gravity data, satellite altimeter information as a direct tracking data type and topographic information. These models define improved representations of the Earth's gravitational potential beyond that available from just satellite or terrestrial data. The development of the degree 360 models, however, does not imply a uniform accuracy in the determination of the gravity field as numerous geographic areas are devoid of terrestrial data or the resolution of such data is limited to, for example, 100 km. This paper will consider theoretical and numerical questions related to the combination of the various data types. Various models of the combination process are discussed with a discussion of various correction terms for the different models. Various sources of gravity data will be described. The new OSU91 360 model will be discussed with comparisons made to previous 360 models and to other potential coefficient models that are complete to degree 50. Future directions in high degree potential coefficient models will be discussed.

  18. Risk assessment based on a combination of historical analysis, a detailed field study and numerical modeling on the alluvial fan Gadeinerbach as a basis for a risk management concept

    Science.gov (United States)

    Moser, M.

    2009-04-01

    The catchment Gadeinerbach in the District of Lungau/Salzburg/Austria is prone to debris flows. Large debris flow events dates back from the years 1934 and 1953. In the upper catchment large mass movements represent debris sources. A field study shows the debris potential and the catchment looks like a "sleeping torrential giant". To carry out mitigation measures a detailed risk management concept, based on a risk assessment in combination of historical analysis, field study and numerical modeling on the alluvial fan was conducted. Human activities have partly altered the surface of the alluvial fan Gadeinerbach but nevertheless some important hazard indicators could be found. With the hazard indicators and photo analysis from the large debris flow event 1934 the catchment character could be pointed out. With the help of these historical data sets (hazard indicators, sediment and debris amount...) it is possible to calibrate the provided numerical models and to win useful knowledge over the pro and cons and their application. The results were used to simulate the design event and furthermore to derive mitigation measures. Therefore the most effective protection against debris with a reduction of the high energy level to a lower level under particular energy change in combination with a debris/bedload deposition place has been carried out. Expert opinion, the study of historical data and a field work is in addition to numerical simulation techniques very necessary for the work in the field of natural hazard management.

  19. Further development of mathematical description for combined toxicity: A case study of lead–fluoride combination

    Directory of Open Access Journals (Sweden)

    Vladimir G. Panov

    2015-01-01

    Full Text Available In this article, we check and develop further some postulates of the theory and mathematical modeling of combined toxic effect that we proposed earlier [1]. To this end, we have analyzed the results of an experiment on rats exposed during 6 weeks to repeated intraperitoneal injections of lead acetate, sodium fluoride or both. The development of intoxication was estimated quantitatively with 54 functional, biochemical and morphometric indices. For mathematical description of the effect that lead and fluorine doses produced alone or in combination, we used a response surface regression model containing linear and cross terms (hyperbolic paraboloid. It is shown that the combination of lead and fluoride features the same 10 types of combined effect that we found previously for the lead and cadmium combination. Special attention is given to indices on which lead and fluorine produce an opposite effect.

  20. Further development of mathematical description for combined toxicity: A case study of lead-fluoride combination.

    Science.gov (United States)

    Panov, Vladimir G; Katsnelson, Boris A; Varaksin, Anatoly N; Privalova, Larisa I; Kireyeva, Ekaterina P; Sutunkova, Marina P; Valamina, Irene E; Beresneva, Olga Yu

    2015-01-01

    In this article, we check and develop further some postulates of the theory and mathematical modeling of combined toxic effect that we proposed earlier [1]. To this end, we have analyzed the results of an experiment on rats exposed during 6 weeks to repeated intraperitoneal injections of lead acetate, sodium fluoride or both. The development of intoxication was estimated quantitatively with 54 functional, biochemical and morphometric indices. For mathematical description of the effect that lead and fluorine doses produced alone or in combination, we used a response surface regression model containing linear and cross terms (hyperbolic paraboloid). It is shown that the combination of lead and fluoride features the same 10 types of combined effect that we found previously for the lead and cadmium combination. Special attention is given to indices on which lead and fluorine produce an opposite effect.

  1. A Bayesian Combination Forecasting Model for Retail Supply Chain Coordination

    Directory of Open Access Journals (Sweden)

    W.J. Wang

    2014-04-01

    Full Text Available Retailing plays an important part in modern economic development, and supply chain coordination is the research focus in retail operations management. This paper reviews the collaborative forecasting process within the framework of the collaborative planning, forecasting and replenishment of retail supply chain. A Bayesian combination forecasting model is proposed to integrate multiple forecasting resources and coordinate forecasting processes among partners in the retail supply chain. Based on simulation results for retail sales, the effectiveness of this combination forecasting model is demonstrated for coordinating the collaborative forecasting processes, resulting in an improvement of demand forecasting accuracy in the retail supply chain.

  2. Linking benthic biodiversity and environmental conditions at the sea floor combining statistical and mechanistic modeling. Case study on the Black Sea's northwestern shelf.

    Science.gov (United States)

    Drion, Roxanne; Capet, Arthur; Gregoire, Marilaure

    2014-05-01

    The preservation of the health and biodiversity of benthic ecosystems is a crucial priority in order to achieve the Good Environmental Status (GES) of marine waters. The multiple pressures acting on the ocean, and in particular, on the coastal zone may prevent the maintenance of biodiversity either directly (e.g. trawling, dredging) or indirectly by modifying environmental conditions at the sea floor (e.g. eutrophication, pollution, acidification, warming). The management of the GES of the benthos in a changing environment and the definition of management strategies (e.g. nutrient reduction) that would preserve GES require tools able to predict the modifications of environmental conditions and to link these modifications to the status of the benthic system. Coupled biogeochemical-circulation models provide a large amount of information on physical (e.g. currents, salinity, temperature, shear stress) and biochemical conditions (e.g. oxygen, inorganic nutrients, sinking detritus) but cannot provide an information on species richness. We propose to link these aspects by applying canonical ordination techniques (e.g. Redundancy Analysis, CoInertia Analysis) on a large data set on macrobenthos collected on the Black Sea's north-western shelf with in-situ sediment data (e.g. granulometry, carbon and nitrogen content, C/N ratio, CaCO3 content) and bottom conditions (e.g. shear stress, level of oxygen stress, flux of organic matter to the sediments) provided by a three dimensional model. Beyond taxonomic description, the analysis is performed on the functional composition of the macrobenthos: A trait-based approach is used to assess the functional composition of the macrobenthos by associating the considered species to a list of biological, ecological and behavioral traits. This approach allows to appraise how local conditions determine the functional and taxonomical diversity and provides a mean to evaluate the impact of habitat alteration on the ecological role of

  3. A Model to Determine the Level of Serum Aldosterone in the Workers Attributed to the Combined Effects of Sound Pressure Level, Exposure Time and Serum Potassium Level: A Field-Based Study

    Directory of Open Access Journals (Sweden)

    Parvin Nassiri

    2016-09-01

    Full Text Available Background Occupational exposure to excessive noise is one of the biggest work-related challenges in the world. This phenomenon causes the release of stress-related hormones, which in turn, negatively affects cardiovascular risk factors. Objectives The current study study aimed to determine the level of workers’ serum aldosterone in light of the combined effect of sound pressure level, exposure time and serum potassium level. Methods This cross-sectional, descriptive, analytical study was conducted on 45 workers of Gol-Gohar Mining and Industrial Company in the fall of 2014. The subjects were divided into three groups (one control and two case groups, each including 15 workers. Participants in the control group were selected from workers with administrative jobs (exposure to the background noise. On the other hand, participants in the case groups were selected from the concentrator and pelletizing factories exposed to excessive noise. Serum aldosterone and potassium levels of participants were assessed at three different time intervals: at the beginning of the shift and before exposure to noise (7:30 - 8:00 AM, during exposure to noise (10:00 - 10:30 AM, and during continuous exposure (1:30 - 2:00 PM. The obtained data were transferred into SPSS ver. 18. Repeated measures analysis of variance (ANOVA was used to develop the statistical model of workers’ aldosterone level in light of the combined effect of sound pressure level, exposure time, and serum potassium level. Results The results of the final statistical model to determine the level of serum aldosterone based on the combined effect of sound pressure level, exposure time and serum potassium level indicated that the sound pressure level had a significant influence on the human’s serum aldosterone level (P = 0.04. In addition, the effects of exposure time and serum potassium on aldosterone level were statistically significant with P-values of 0.008 and 0.001, respectively. Conclusions

  4. Effects of Isomalt on enamel de- and remineralization, a combined in vitro pH-cycling model and in situ study.

    Science.gov (United States)

    Takatsuka, Tsutomu; Exterkate, Rob A M; ten Cate, Jacob M

    2008-06-01

    Isomalt is a non-cariogenic sweetener, which is widely used in sugar-free candy and chewing gum. Little is known about the effects of Isomalt on de- and remineralization. Binding between calcium and Isomalt has been reported, which could affect the mineral balance. The objective of this study was to examine the effects of Isomalt on de- and remineralization of bovine enamel lesions, both in vitro and in situ. In in vitro study, subsurface enamel lesions were subjected to 3-weeks pH-cycling. Treatments were 5-min rinses with 10% Isomalt solutions daily and 10% Isomalt additions to re- or demineralizing solutions. Standard pH-cycling conditions were used with a 0.2 ppm fluoride background during the remineralization phase. In in situ study, subsurface lesions were exposed 2 months in vivo and brushed three times daily with 10% Isomalt containing toothpaste. Treatment effects were assessed by chemical analysis of the solutions (in vitro) and transversal microradiography (in vitro and in situ). In in vitro study, while 5-min rinses with 10% Isomalt gave slightly increased remineralization, continuous presence of 10% Isomalt (in re- or demineralizing solutions) inhibited both de- and/or remineralization. This lead to significantly smaller overall mineral loss when Isomalt was added during demineralization. In in situ study, remineralization enhancement during short Isomalt treatments was confirmed. Isomalt had a positive effect on the de/remineralization balance when given under conditions relevant to practical use.

  5. Effects of Isomalt on enamel de- and remineralization, a combined in vitro pH-cycling model and in situ study

    NARCIS (Netherlands)

    Takatsuka, T.; Exterkate, R.A.M.; ten Cate, J.M.

    2008-01-01

    Isomalt is a non-cariogenic sweetener, which is widely used in sugar-free candy and chewing gum. Little is known about the effects of Isomalt on de- and remineralization. Binding between calcium and Isomalt has been reported, which could affect the mineral balance. The objective of this study was to

  6. Activity in the fronto-parietal network indicates numerical inductive reasoning beyond calculation: An fMRI study combined with a cognitive model

    OpenAIRE

    Peipeng Liang; Xiuqin Jia; Niels A Taatgen; Borst, Jelmer P.; Kuncheng Li

    2016-01-01

    Numerical inductive reasoning refers to the process of identifying and extrapolating the rule involved in numeric materials. It is associated with calculation, and shares the common activation of the fronto-parietal regions with calculation, which suggests that numerical inductive reasoning may correspond to a general calculation process. However, compared with calculation, rule identification is critical and unique to reasoning. Previous studies have established the central role of the front...

  7. Numerical Modelling of Sediment Transport in Combined Sewer Systems

    DEFF Research Database (Denmark)

    Schlütter, Flemming

    A conceptual sediment transport model has been developed. Through a case study a comparison with other numerical models is performed.......A conceptual sediment transport model has been developed. Through a case study a comparison with other numerical models is performed....

  8. Making sense of perceptions of risk of diseases and vaccinations: a qualitative study combining models of health beliefs, decision-making and risk perception

    Directory of Open Access Journals (Sweden)

    Bond Lyndal

    2011-12-01

    Full Text Available Abstract Background Maintaining high levels of childhood vaccinations is important for public health. Success requires better understanding of parents' perceptions of diseases and consequent decisions about vaccinations, however few studies have considered this from the theoretical perspectives of risk perception and decision-making under uncertainty. The aim of this study was to examine the utility of subjective risk perception and decision-making theories to provide a better understanding of the differences between immunisers' and non-immunisers' health beliefs and behaviours. Methods In a qualitative study we conducted semi-structured in-depth interviews with 45 Australian parents exploring their experiences and perceptions of disease severity and susceptibility. Using scenarios about 'a new strain of flu' we explored how risk information was interpreted. Results We found that concepts of dread, unfamiliarity, and uncontrollability from the subjective perception of risk and ambiguity, optimistic control and omission bias from explanatory theories of decision-making under uncertainty were useful in understanding why immunisers, incomplete immunisers and non-immunisers interpreted severity and susceptibility to diseases and vaccine risk differently. Immunisers dreaded unfamiliar diseases whilst non-immunisers dreaded unknown, long term side effects of vaccines. Participants believed that the risks of diseases and complications from diseases are not equally spread throughout the community, therefore, when listening to reports of epidemics, it is not the number of people who are affected but the familiarity or unfamiliarity of the disease and the characteristics of those who have had the disease that prompts them to take preventive action. Almost all believed they themselves would not be at serious risk of the 'new strain of flu' but were less willing to take risks with their children's health. Conclusion This study has found that health messages

  9. Computer modelling in combination with in vitro studies reveals similar binding affinities of Drosophila Crumbs for the PDZ domains of Stardust and DmPar-6.

    Science.gov (United States)

    Kempkens, Ozlem; Médina, Emmanuelle; Fernandez-Ballester, Gregorio; Ozüyaman, Susann; Le Bivic, André; Serrano, Luis; Knust, Elisabeth

    2006-08-01

    Formation of multiprotein complexes is a common theme to pattern a cell, thereby generating spatially and functionally distinct entities at specialised regions. Central components of these complexes are scaffold proteins, which contain several protein-protein interaction domains and provide a platform to recruit a variety of additional components. There is increasing evidence that protein complexes are dynamic structures and that their components can undergo various interactions depending on the cellular context. However, little is known so far about the factors regulating this behaviour. One evolutionarily conserved protein complex, which can be found both in Drosophila and mammalian epithelial cells, is composed of the transmembrane protein Crumbs/Crb3 and the scaffolding proteins Stardust/Pals1 and DPATJ/PATJ, respectively, and localises apically to the zonula adherens. Here we show by in vitro analysis that, similar as in vertebrates, the single PDZ domain of Drosophila DmPar-6 can bind to the four C-terminal amino acids (ERLI) of the transmembrane protein Crumbs. To further evaluate the binding capability of Crumbs to DmPar-6 and the MAGUK protein Stardust, analysis of the PDZ structural database and modelling of the interactions between the C-terminus of Crumbs and the PDZ domains of these two proteins were performed. The results suggest that both PDZ domains bind Crumbs with similar affinities. These data are supported by quantitative yeast two-hybrid interactions. In vivo analysis performed in cell cultures and in the Drosophila embryo show that the cytoplasmic domain of Crumbs can recruit DmPar-6 and DaPKC to the plasma membrane. The data presented here are discussed with respect to possible dynamic interactions between these proteins.

  10. MCNP modelling of a combined neutron/gamma counter

    CERN Document Server

    Bourva, L C A; Ottmar, H; Weaver, D R

    1999-01-01

    A series of Monte Carlo neutron calculations for a combined gamma/passive neutron coincidence counter has been performed. This type of device, part of a suite of non-destructive assay instruments utilised for the enforcement of the Euratom nuclear safeguards within the European Union, is to be used for high accuracy measurements of the plutonium content of small samples of nuclear materials. The multi-purpose Monte Carlo N-particle (MCNP) code version 4B has been used to model in detail the neutron coincidence detector and to investigate the leakage self-multiplication of PuO sub 2 and mixed U-Pu oxide (MOX) reference samples used to calibrate the instrument. The MCNP calculations have been used together with a neutron coincidence counting interpretative model to determine characteristic parameters of the detector. A comparative study to both experimental and previous numerical results has been performed. Sensitivity curves of the variation of the detector's efficiency, epsilon, to, alpha, the ratio of (alpha...

  11. Combined photovoltaic/thermal solar array dc electrical model

    Energy Technology Data Exchange (ETDEWEB)

    Krikorian, J.S. Jr.

    1981-12-01

    An electrical model of a combined photovoltaic/thermal solar array has been developed to predict the steady state behavior of the line currents, power output and array voltage. The effects of temperature on the solar cell characteristics is included in the analysis. The model includes line isolation diodes and ''open cell'' bypass diodes. A numerical procedure based on the Contraction Mapping Fixed Point Theorem is used to solve the associated nonlinear equations. 6 refs.

  12. Combining Diffusion and Grey Models Based on Evolutionary Optimization Algorithms to Forecast Motherboard Shipments

    Directory of Open Access Journals (Sweden)

    Fu-Kwun Wang

    2012-01-01

    Full Text Available It is important for executives to predict the future trends. Otherwise, their companies cannot make profitable decisions and investments. The Bass diffusion model can describe the empirical adoption curve for new products and technological innovations. The Grey model provides short-term forecasts using four data points. This study develops a combined model based on the rolling Grey model (RGM and the Bass diffusion model to forecast motherboard shipments. In addition, we investigate evolutionary optimization algorithms to determine the optimal parameters. Our results indicate that the combined model using a hybrid algorithm outperforms other methods for the fitting and forecasting processes in terms of mean absolute percentage error.

  13. Combined Estimation of Hydrogeologic Conceptual Model and Parameter Uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Philip D.; Ye, Ming; Neuman, Shlomo P.; Cantrell, Kirk J.

    2004-03-01

    The objective of the research described in this report is the development and application of a methodology for comprehensively assessing the hydrogeologic uncertainties involved in dose assessment, including uncertainties associated with conceptual models, parameters, and scenarios. This report describes and applies a statistical method to quantitatively estimate the combined uncertainty in model predictions arising from conceptual model and parameter uncertainties. The method relies on model averaging to combine the predictions of a set of alternative models. Implementation is driven by the available data. When there is minimal site-specific data the method can be carried out with prior parameter estimates based on generic data and subjective prior model probabilities. For sites with observations of system behavior (and optionally data characterizing model parameters), the method uses model calibration to update the prior parameter estimates and model probabilities based on the correspondence between model predictions and site observations. The set of model alternatives can contain both simplified and complex models, with the requirement that all models be based on the same set of data. The method was applied to the geostatistical modeling of air permeability at a fractured rock site. Seven alternative variogram models of log air permeability were considered to represent data from single-hole pneumatic injection tests in six boreholes at the site. Unbiased maximum likelihood estimates of variogram and drift parameters were obtained for each model. Standard information criteria provided an ambiguous ranking of the models, which would not justify selecting one of them and discarding all others as is commonly done in practice. Instead, some of the models were eliminated based on their negligibly small updated probabilities and the rest were used to project the measured log permeabilities by kriging onto a rock volume containing the six boreholes. These four

  14. Direct model fitting to combine dithered ACS images

    Science.gov (United States)

    Mahmoudian, H.; Wucknitz, O.

    2013-08-01

    The information lost in images of undersampled CCD cameras can be recovered with the technique of "dithering". A number of subexposures is taken with sub-pixel shifts in order to record structures on scales smaller than a pixel. The standard method to combine such exposures, "Drizzle", averages after reversing the displacements, including rotations and distortions. More sophisticated methods are available to produce, e.g., Nyquist sampled representations of band-limited inputs. While the combined images produced by these methods can be of high quality, their use as input for forward-modelling techniques in gravitational lensing is still not optimal, because the residual artefacts still affect the modelling results in unpredictable ways. In this paper we argue for an overall modelling approach that takes into account the dithering and the lensing without the intermediate product of a combined image. As one building block we introduce an alternative approach to combine dithered images by direct model fitting with a least-squares approach including a regularization constraint. We present tests with simulated and real data that show the quality of the results. The additional effects of gravitational lensing and the convolution with an instrumental point spread function can be included in a natural way, avoiding the possible systematic errors of previous procedures.

  15. Combining molecular dynamics simulation and ligand-receptor contacts analysis as a new approach for pharmacophore modeling: beta-secretase 1 and check point kinase 1 as case studies.

    Science.gov (United States)

    Hatmal, Ma'mon M; Jaber, Shadi; Taha, Mutasem O

    2016-12-01

    Ligand-based pharmacophore modeling require relatively long lists of active compounds, while a pharmacophore based on a single ligand-receptor crystallographic structure is often promiscuous. These problems prompted us to combine molecular dynamics (MD) simulation with ligand-receptor contacts analysis as means to develop valid pharmacophore model(s). The particular ligand-receptor complex is allowed to perturb over a few nano-seconds using MD simulation. Subsequently, ligand-receptor contact points (≤2.5 Å) are identified. Ligand-receptor contacts maintained above certain threshold during molecular dynamics simulation are considered critical and used to guide pharmacophore development. We termed this method as Molecular-Dynamics Based Ligand-Receptor Contact Analysis. We implemented this new methodology to develop valid pharmacophore models for check point kinase 1 (Chk1) and beta-secretase 1 (BACE1) inhibitors as case studies. The resulting pharmacophore models were validated by receiver operating characteristic curved analysis against inhibitors obtained from CHEMBL database.

  16. Combining molecular dynamics simulation and ligand-receptor contacts analysis as a new approach for pharmacophore modeling: beta-secretase 1 and check point kinase 1 as case studies

    Science.gov (United States)

    Hatmal, Ma'mon M.; Jaber, Shadi; Taha, Mutasem O.

    2016-12-01

    Ligand-based pharmacophore modeling require relatively long lists of active compounds, while a pharmacophore based on a single ligand-receptor crystallographic structure is often promiscuous. These problems prompted us to combine molecular dynamics (MD) simulation with ligand-receptor contacts analysis as means to develop valid pharmacophore model(s). The particular ligand-receptor complex is allowed to perturb over a few nano-seconds using MD simulation. Subsequently, ligand-receptor contact points (≤2.5 Å) are identified. Ligand-receptor contacts maintained above certain threshold during molecular dynamics simulation are considered critical and used to guide pharmacophore development. We termed this method as Molecular-Dynamics Based Ligand-Receptor Contact Analysis. We implemented this new methodology to develop valid pharmacophore models for check point kinase 1 (Chk1) and beta-secretase 1 (BACE1) inhibitors as case studies. The resulting pharmacophore models were validated by receiver operating characteristic curved analysis against inhibitors obtained from CHEMBL database.

  17. The study of cell homeostasis state of the gastric mucosa of rats on model of rheumatoid arthritis , treatment with ibuprofen and its combination with vinboron

    Directory of Open Access Journals (Sweden)

    F. V. Hladkykh

    2016-01-01

    Full Text Available Introduction. The use of NSAIDs in clinical practice is known for a significant reduction of side effects risks, among which the largest share of toxic effects on the digestive system. At the same time, the attention of researchers is increasingly payed to a specific syndrome associated with application of this group of drugs – NSAIDs gastropathy, with necrosis of epithelial cells as a possible morphological substrate. However, as the recent studies have shown, necrosis is not the only, but also is not the main cause of cell death. Apoptosis, the programmed cell death, is observed more often than necrosis. Besides, ulcerogenesis problem is closely linked to the ability of the gastric mucosa epithelium to adequate regeneration. This necessitates a search for the ways to correct the effect of non-steroidal antiphlogistics on the processes of apoptosis and proliferous activity of epithelial cells of the gastric mucosa. Materials and methods. Immunohistochemical studies were performed on paraffin sections using streptavidin-biotin method (“DAKO”, Denmark; LSAB2 Systems, HRP. Antigen unmasking was performed in citrate buffer pH 6.0. Mice`s and rabbit`s monoclonal antibodies were used as the primary antibodies. The cell nuclei were colored with Mayer’s hematoxylin for 15-60 seconds. Condition gastric epithelial proliferative activity was studied using a mouse monoclonal antibody to nuclear antigen Ki-67 (“DAKO”, MIB-1 clone, Denmark as a sensitive marker of proliferation by T. Scholzen. To characterize the activity of apoptosis the expression of CPP32 (caspase-3 in the gastric mucosa was examined, using semiquantitative rating scale color intensity of 0 (none – no positive reactions in cells, 1 (weak – up to 30% of the cells reacted positively 2 (moderate – 31-60%, and 3 (strong – 60% more stained cells.Results and Discussion. Analysis of the results of immunohistochemical expression

  18. Discrimination of edible oils and fats by combination of multivariate pattern recognition and FT-IR spectroscopy: A comparative study between different modeling methods

    Science.gov (United States)

    Javidnia, Katayoun; Parish, Maryam; Karimi, Sadegh; Hemmateenejad, Bahram

    2013-03-01

    By using FT-IR spectroscopy, many researchers from different disciplines enrich the experimental complexity of their research for obtaining more precise information. Moreover chemometrics techniques have boosted the use of IR instruments. In the present study we aimed to emphasize on the power of FT-IR spectroscopy for discrimination between different oil samples (especially fat from vegetable oils). Also our data were used to compare the performance of different classification methods. FT-IR transmittance spectra of oil samples (Corn, Colona, Sunflower, Soya, Olive, and Butter) were measured in the wave-number interval of 450-4000 cm-1. Classification analysis was performed utilizing PLS-DA, interval PLS-DA, extended canonical variate analysis (ECVA) and interval ECVA methods. The effect of data preprocessing by extended multiplicative signal correction was investigated. Whilst all employed method could distinguish butter from vegetable oils, iECVA resulted in the best performances for calibration and external test set with 100% sensitivity and specificity.

  19. A combined mean dynamic topography model - DTU16MDT

    Science.gov (United States)

    Knudsen, Per; Andersen, Ole; Nielsen, Karina; Maximenko, Nikolai

    2017-04-01

    The new DTU16MDT is obtained by combining the geodetic mean dynamic topography DTU15MDT with drifter mean velocities. DTU15MDT had been derived using the gravity model EIGEN-6C4 combined with the DTU15MSS mean sea surface model. The EIGEN-6C4 is derived using the full series of GOCE data and provides a better resolution. The better resolution fixes a few problems related to geoid signals in the former model DTU13MDT. Slicing in the GOCO05S gravity model up to harmonic degree 150 has solved some issues related to striations. Compared to the DTU13MSS, the DTU15MSS has been derived by including re-tracked CRYOSAT-2 altimetry also, hence, increasing its resolution. Also, some issues in the Polar regions have been solved. Finally, the filtering was re-evaluated by adjusting the quasi-gaussian filter width to optimize the fit to drifter velocities. Subsequently, the drifter velocities were integrated to enhance the resolution of the MDT. The results show that the new MDT resolves the details of the ocean circulation much better. Finally, mean drifter velocities have been integrated in the computations for the combined MDT model.

  20. Convex Combination of Multiple Statistical Models with Application to VAD

    DEFF Research Database (Denmark)

    Petsatodis, Theodoros; Boukis, Christos; Talantzis, Fotios

    2011-01-01

    This paper proposes a robust Voice Activity Detector (VAD) based on the observation that the distribution of speech captured with far-field microphones is highly varying, depending on the noise and reverberation conditions. The proposed VAD employs a convex combination scheme comprising three...... statistical distributions - a Gaussian, a Laplacian, and a two-sided Gamma - to effectively model captured speech. This scheme shows increased ability to adapt to dynamic acoustic environments. The contribution of each distribution to this convex combination is automatically adjusted based on the statistical...

  1. Combining Diffusion and Grey Models Based on Evolutionary Optimization Algorithms to Forecast Motherboard Shipments

    OpenAIRE

    Fu-Kwun Wang; Yu-Yao Hsiao; Ku-Kuang Chang

    2012-01-01

    It is important for executives to predict the future trends. Otherwise, their companies cannot make profitable decisions and investments. The Bass diffusion model can describe the empirical adoption curve for new products and technological innovations. The Grey model provides short-term forecasts using four data points. This study develops a combined model based on the rolling Grey model (RGM) and the Bass diffusion model to forecast motherboard shipments. In addition, we investigate evolutio...

  2. Combining Diffusion and Grey Models Based on Evolutionary Optimization Algorithms to Forecast Motherboard Shipments

    OpenAIRE

    Fu-Kwun Wang; Yu-Yao Hsiao; Ku-Kuang Chang

    2012-01-01

    It is important for executives to predict the future trends. Otherwise, their companies cannot make profitable decisions and investments. The Bass diffusion model can describe the empirical adoption curve for new products and technological innovations. The Grey model provides short-term forecasts using four data points. This study develops a combined model based on the rolling Grey model (RGM) and the Bass diffusion model to forecast motherboard shipments. In addition, we investigate evolutio...

  3. A combined model reduction algorithm for controlled biochemical systems.

    Science.gov (United States)

    Snowden, Thomas J; van der Graaf, Piet H; Tindall, Marcus J

    2017-02-13

    Systems Biology continues to produce increasingly large models of complex biochemical reaction networks. In applications requiring, for example, parameter estimation, the use of agent-based modelling approaches, or real-time simulation, this growing model complexity can present a significant hurdle. Often, however, not all portions of a model are of equal interest in a given setting. In such situations methods of model reduction offer one possible approach for addressing the issue of complexity by seeking to eliminate those portions of a pathway that can be shown to have the least effect upon the properties of interest. In this paper a model reduction algorithm bringing together the complementary aspects of proper lumping and empirical balanced truncation is presented. Additional contributions include the development of a criterion for the selection of state-variable elimination via conservation analysis and use of an 'averaged' lumping inverse. This combined algorithm is highly automatable and of particular applicability in the context of 'controlled' biochemical networks. The algorithm is demonstrated here via application to two examples; an 11 dimensional model of bacterial chemotaxis in Escherichia coli and a 99 dimensional model of extracellular regulatory kinase activation (ERK) mediated via the epidermal growth factor (EGF) and nerve growth factor (NGF) receptor pathways. In the case of the chemotaxis model the algorithm was able to reduce the model to 2 state-variables producing a maximal relative error between the dynamics of the original and reduced models of only 2.8% whilst yielding a 26 fold speed up in simulation time. For the ERK activation model the algorithm was able to reduce the system to 7 state-variables, incurring a maximal relative error of 4.8%, and producing an approximately 10 fold speed up in the rate of simulation. Indices of controllability and observability are additionally developed and demonstrated throughout the paper. These provide

  4. Combinations of genetic data in a study of oral cancer

    DEFF Research Database (Denmark)

    Mellerup, Erling Thyge; Møller, Gert Lykke; Mondal, Pinaki

    2015-01-01

    for a polygenic disorder will not occur in in control persons genetically unrelated to patients, so the strategy is to analyze combinations of genetic variants present exclusively in patients. In a previous study of oral cancer and leukoplakia 325 SNPs were analyzed. This study has been supplemented...... with an analysis of combinations of two SNP genotypes from among the 325 SNPs. Two clusters of combinations containing 95 patient specific combinations were significantly associated with oral cancer or leukoplakia. Of 373 patients with oral cancer 205 patients had a number of these 95 combinations in their genome...

  5. Combining Spatial and Telemetric Features for Learning Animal Movement Models

    CERN Document Server

    Kapicioglu, Berk; Wikelski, Martin; Broderick, Tamara

    2012-01-01

    We introduce a new graphical model for tracking radio-tagged animals and learning their movement patterns. The model provides a principled way to combine radio telemetry data with an arbitrary set of userdefined, spatial features. We describe an efficient stochastic gradient algorithm for fitting model parameters to data and demonstrate its effectiveness via asymptotic analysis and synthetic experiments. We also apply our model to real datasets, and show that it outperforms the most popular radio telemetry software package used in ecology. We conclude that integration of different data sources under a single statistical framework, coupled with appropriate parameter and state estimation procedures, produces both accurate location estimates and an interpretable statistical model of animal movement.

  6. Combined effect of tobacco smoking and alcohol drinking in the risk of head and neck cancers: a re-analysis of case-control studies using bi-dimensional spline models.

    Science.gov (United States)

    Dal Maso, Luigino; Torelli, Nicola; Biancotto, Elisa; Di Maso, Matteo; Gini, Andrea; Franchin, Gianni; Levi, Fabio; La Vecchia, Carlo; Serraino, Diego; Polesel, Jerry

    2016-04-01

    The synergistic effect of tobacco smoking and alcohol consumption on the risk of head and neck cancers has been mainly investigated as a cross-product of categorical exposure, thus leading to loss of information. We propose a bi-dimensional logistic spline model to investigate the interacting dose-response relationship of two continuous exposures (i.e., ethanol intake and tobacco smoking) on the risk of head and neck cancers, representing results through three-dimensional graphs. This model was applied to a pool of hospital-based case-control studies on head and neck cancers conducted in Italy and in the Vaud Swiss Canton between 1982 and 2000, including 1569 cases and 3147 controls. Among never drinkers and for all levels of ethanol intake, the risk of head and neck cancers steeply increased with increasing smoking intensity, starting from 1 cigarette/day. The risk associated to ethanol intake increased with incrementing exposure among smokers, and a threshold effect at approximately 50 g/day emerged among never smokers. Compared to abstainers from both tobacco and alcohol consumption, the combined exposure to ethanol and/or cigarettes led to a steep increase of cancer risk up to a 35-fold higher risk (95 % confidence interval 27.30-43.61) among people consuming 84 g/day of ethanol and 10 cigarettes/day. The highest risk was observed at the highest levels of alcohol and tobacco consumption. Our findings confirmed a combined effect of tobacco smoking and alcohol drinking on head and neck cancers risk, providing evidence that bi-dimensional spline models could be a feasible and flexible method to explore the pattern of risks associated to two interacting continuous-exposure variables.

  7. Demand Model Combining Stated And Revealed Preference Data

    Directory of Open Access Journals (Sweden)

    Luciana Londero Brandli

    2007-10-01

    Full Text Available The revealed and stated preference methods have been contributing a lot for the development of the econometric literature in the attempt of determining the variables that influence the individual decision in a choice process. This article combines preference data, with the objective of obtaining the advantages of the complementarity of the forces and frankness of both types of data. The approach involves the estimate of a model only with RP data, only with SP data and combining RP and SP data. The application is in the housing market, where it is observed, through the literature, that most of the papers of the consumer's choice has restricted the only one approaches. The utility functions obtained show the relative importance of the attributes, the tendency of behavior through the signs and its significance statistical. The results analysis of the models indicates differences and similarities about the attribute’s behavior.

  8. User Modeling Combining Access Logs, Page Content and Semantics

    CERN Document Server

    Fortuna, Blaz; Grobelnik, Marko

    2011-01-01

    The paper proposes an approach to modeling users of large Web sites based on combining different data sources: access logs and content of the accessed pages are combined with semantic information about the Web pages, the users and the accesses of the users to the Web site. The assumption is that we are dealing with a large Web site providing content to a large number of users accessing the site. The proposed approach represents each user by a set of features derived from the different data sources, where some feature values may be missing for some users. It further enables user modeling based on the provided characteristics of the targeted user subset. The approach is evaluated on real-world data where we compare performance of the automatic assignment of a user to a predefined user segment when different data sources are used to represent the users.

  9. INVESTIGATION OF DIFFERENT MODELS OF COMBINED PARALLEL FLASH BINARY CYCLES

    OpenAIRE

    A. Jafar Yazdi*

    2017-01-01

    The aim of this paper is a comparative study of the different geothermal power plant concepts, based on the energy and exergy analysis. The cycles studied in this paper are the combination of single and double flash power plants with two different ORC cycles as basic Organic Rankine Cycle (ORC), ORC with IHE, regenerative ORC and regenerative ORC with an IHE. The main gain due to using combined flash-binary power plants with various types of ORCs is to achieve optimum and efficient energy uti...

  10. Language Model Combination and Adaptation Using Weighted Finite State Transducers

    Science.gov (United States)

    Liu, X.; Gales, M. J. F.; Hieronymus, J. L.; Woodland, P. C.

    2010-01-01

    In speech recognition systems language model (LMs) are often constructed by training and combining multiple n-gram models. They can be either used to represent different genres or tasks found in diverse text sources, or capture stochastic properties of different linguistic symbol sequences, for example, syllables and words. Unsupervised LM adaption may also be used to further improve robustness to varying styles or tasks. When using these techniques, extensive software changes are often required. In this paper an alternative and more general approach based on weighted finite state transducers (WFSTs) is investigated for LM combination and adaptation. As it is entirely based on well-defined WFST operations, minimum change to decoding tools is needed. A wide range of LM combination configurations can be flexibly supported. An efficient on-the-fly WFST decoding algorithm is also proposed. Significant error rate gains of 7.3% relative were obtained on a state-of-the-art broadcast audio recognition task using a history dependently adapted multi-level LM modelling both syllable and word sequences

  11. Solvation of chromone using combined Discrete/SCRF models

    Science.gov (United States)

    Alemán, Carlos; Galembeck, Sergio E.

    1998-06-01

    The solvation of chromone has been investigated using three different combined Discrete/SCRF models. Four chromone-H 2O complexes and one chromone-4H 2O complex were obtained from geometry optimizations at the HF/6-31G(d) level. Three SCRF methods (PCM/6-31G(d), PCM/AM1 and SM2/AM1) were applied to such complexes in order to: (1) evaluate the reliability of the combined Discrete/SCRF models; (2) investigate the effects of the explicit water molecules on the free energy of solvation; and (3) analyze the characteristics of the different solvation sites of chromone. The results show that explicit solvent molecules exert a large influence on the free energy of solvation of a given molecular system providing some information about the solvation sites. Thus, the interaction of the carbonyl oxygen of chromone with the explicit water molecules is stronger than interaction provided by the ether oxygen, providing the complexes with the former interaction a more hydrophobic free energy of solvation than those with the latter. On the other hand, the comparison of the free energies of solvation for solutes with explicit water molecules in the first hydration shell and the free energies of solvation of the molecular system computed in an all-continuum approach reveals that the combined Discrete/SCRF models constitute a very reasonable strategy.

  12. Combined Grammar for the Modeling of Building Interiors

    Science.gov (United States)

    Becker, S.; Peter, M.; Fritsch, D.; Philipp, D.; Baier, P.; Dibak, C.

    2013-11-01

    As spatial grammars have proven successful and efficient to deliver LOD3 models, the next challenge is their extension to indoor applications, leading to LOD4 models. Therefore, a combined indoor grammar for the automatic generation of indoor models from erroneous and incomplete observation data is presented. In building interiors where inaccurate observation data is available, the grammar can be used to make the reconstruction process robust, and verify the reconstructed geometries. In unobserved building interiors, the grammar can generate hypotheses about possible indoor geometries matching the style of the rest of the building. The grammar combines concepts from L-systems and split grammars. It is designed in such way that it can be derived from observation data fully automatically. Thus, manual predefinitions of the grammar rules usually required to tune the grammar to a specific building style, become obsolete. The potential benefit of using our grammar as support for indoor modeling is evaluated based on an example where the grammar has been applied to automatically generate an indoor model from erroneous and incomplete traces gathered by foot-mounted MEMS/IMU positioning systems.

  13. Advanced Performance Modeling with Combined Passive and Active Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Dovrolis, Constantine [Georgia Inst. of Technology, Atlanta, GA (United States); Sim, Alex [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-04-15

    To improve the efficiency of resource utilization and scheduling of scientific data transfers on high-speed networks, the "Advanced Performance Modeling with combined passive and active monitoring" (APM) project investigates and models a general-purpose, reusable and expandable network performance estimation framework. The predictive estimation model and the framework will be helpful in optimizing the performance and utilization of networks as well as sharing resources with predictable performance for scientific collaborations, especially in data intensive applications. Our prediction model utilizes historical network performance information from various network activity logs as well as live streaming measurements from network peering devices. Historical network performance information is used without putting extra load on the resources by active measurement collection. Performance measurements collected by active probing is used judiciously for improving the accuracy of predictions.

  14. Combined physical and chemical nonequilibrium transport model for solution conduits.

    Science.gov (United States)

    Field, Malcolm S; Leij, Feike J

    2014-02-01

    Solute transport in karst aquifers is primarily constrained to relatively complex and inaccessible solution conduits where transport is often rapid, turbulent, and at times constrictive. Breakthrough curves generated from tracer tests in solution conduits are typically positively-skewed with long tails evident. Physical nonequilibrium models to fit breakthrough curves for tracer tests in solution conduits are now routinely employed. Chemical nonequilibrium processes are likely important interactions, however. In addition to partitioning between different flow domains, there may also be equilibrium and nonequilibrium partitioning between the aqueous and solid phases. A combined physical and chemical nonequilibrium (PCNE) model was developed for an instantaneous release similar to that developed by Leij and Bradford (2009) for a pulse release. The PCNE model allows for partitioning open space in solution conduits into mobile and immobile flow regions with first-order mass transfer between the two regions to represent physical nonequilibrium in the conduit. Partitioning between the aqueous and solid phases proceeds either as an equilibrium process or as a first-order process and represents chemical nonequilibrium for both the mobile and immobile regions. Application of the model to three example breakthrough curves demonstrates the applicability of the combined physical and chemical nonequilibrium model to tracer tests conducted in karst aquifers, with exceptionally good model fits to the data. The three models, each from a different state in the United States, exhibit very different velocities, dispersions, and other transport properties with most of the transport occurring via the fraction of mobile water. Fitting the model suggests the potentially important interaction of physical and chemical nonequilibrium processes.

  15. Modelling of the Secondary Clarifier Combined with the Activated Sludge Model no. 1

    DEFF Research Database (Denmark)

    Dupont, René; Henze, Mogens

    1992-01-01

    settling, which can be used in combination with the Activated Sludge Model to form a dynamic computer model/program for a wastewater treatment plant. In addition to the flux model, the developed model includes a simple model for predicting the contents of particulate components in the effluent. This latter......Modelling of activated sludge wastewater treatment plants is today generally based on the Activated Sludge Model No. 1 combined with a very simple model for the secondary settler. This paper describes the development of a model for the secondary clarifier based on the general flux theory for zone...... model is a purely empirical model, which connects the effluent quality with the hydraulic load, suspended solids load and the nitrate load. The paper describes the model and gives some basic examples on computer simulations and verification of the model....

  16. Impacts of combining reanalyses and weather station data on the accuracy of discharge modelling

    Science.gov (United States)

    Essou, Gilles R. C.; Brissette, François; Lucas-Picher, Philippe

    2017-02-01

    Reanalyses are important sources of meteorological data. Recent studies have shown that precipitation and temperature data from reanalysis present a strong potential for hydrological modelling, especially in regions with a sparse observational network. The objective of this study is to evaluate the impacts of the combination of three global atmospheric reanalyses - ERA-Interim, CFSR and MERRA - and one gridded observation dataset on the accuracy of hydrological model discharge simulations. Two combination approaches were used. The first one combined reanalyses and the observational database using a weighted average of the precipitation and temperature inputs. The second one consisted in using all meteorological inputs separately and combining the simulated hydrographs. The combinations were performed over 460 Canadian watersheds (representing regions with a low density of weather stations) and 370 US watersheds (representing regions with a higher density of weather stations). Results showed significant improvements in the simulated discharges for 68% and 92% of the Canadian watersheds for the input combinations and output combinations, respectively. Moreover, both approaches led to significant improvements in the simulated discharges for 72% of the US watersheds studied. For all watersheds where simulated discharges using observational data had a Nash Sutcliffe efficiency (NSE) lower than 0.5, the combination with reanalyses resulted in a median NSE increase of 0.3. This indicates that reanalysis can successfully compensate for deficiencies in the surface observation record and provide significantly better hydrological modelling performance.

  17. Modelling of the Secondary Clarifier Combined with the Activated Sludge Model no. 1

    DEFF Research Database (Denmark)

    Dupont, René; Henze, Mogens

    1992-01-01

    Modelling of activated sludge wastewater treatment plants is today generally based on the Activated Sludge Model No. 1 combined with a very simple model for the secondary settler. This paper describes the development of a model for the secondary clarifier based on the general flux theory for zone...

  18. Symbolic Processing Combined with Model-Based Reasoning

    Science.gov (United States)

    James, Mark

    2009-01-01

    A computer program for the detection of present and prediction of future discrete states of a complex, real-time engineering system utilizes a combination of symbolic processing and numerical model-based reasoning. One of the biggest weaknesses of a purely symbolic approach is that it enables prediction of only future discrete states while missing all unmodeled states or leading to incorrect identification of an unmodeled state as a modeled one. A purely numerical approach is based on a combination of statistical methods and mathematical models of the applicable physics and necessitates development of a complete model to the level of fidelity required for prediction. In addition, a purely numerical approach does not afford the ability to qualify its results without some form of symbolic processing. The present software implements numerical algorithms to detect unmodeled events and symbolic algorithms to predict expected behavior, correlate the expected behavior with the unmodeled events, and interpret the results in order to predict future discrete states. The approach embodied in this software differs from that of the BEAM methodology (aspects of which have been discussed in several prior NASA Tech Briefs articles), which provides for prediction of future measurements in the continuous-data domain.

  19. Ionospheric parameter modelling and anomaly discovery by combining the wavelet transform with autoregressive models

    Directory of Open Access Journals (Sweden)

    Oksana V. Mandrikova

    2015-11-01

    Full Text Available The paper is devoted to new mathematical tools for ionospheric parameter analysis and anomaly discovery during ionospheric perturbations. The complex structure of processes under study, their a-priori uncertainty and therefore the complex structure of registered data require a set of techniques and technologies to perform mathematical modelling, data analysis, and to make final interpretations. We suggest a technique of ionospheric parameter modelling and analysis based on combining the wavelet transform with autoregressive integrated moving average models (ARIMA models. This technique makes it possible to study ionospheric parameter changes in the time domain, make predictions about variations, and discover anomalies caused by high solar activity and lithospheric processes prior to and during strong earthquakes. The technique was tested on critical frequency foF2 and total electron content (TEC datasets from Kamchatka (a region in the Russian Far East and Magadan (a town in the Russian Far East. The mathematical models introduced in the paper facilitated ionospheric dynamic mode analysis and proved to be efficient for making predictions with time advance equal to 5 hours. Ionospheric anomalies were found using model error estimates, those anomalies arising during increased solar activity and strong earthquakes in Kamchatka.

  20. Research of combined liver-kidney transplantation model in rats

    Institute of Scientific and Technical Information of China (English)

    Jiageng Zhu; Jun Li; Ruipeng Jia; Jianghao Su; Mingshun Shen; Zhigang Cao

    2007-01-01

    Objective: To set up a simple and reliable rat model of combined liver-kidney transplantation. Methods: SD rats served as both donors and recipients. 4℃ sodium lactate Ringer's was infused from portal veins to donated livers,and from abdominal aorta to donated kidneys, respectively. Anastomosis of the portal vein and the inferior vena cava (IVC) inferior to the right kidney between the graft and the recipient was performed by a double cuff method, then the superior hepatic vena cava with suture. A patch of donated renal artery was anastomosed to the recipient abdominal aorta. The urethra and bile duct were reconstructed with a simple inside bracket. Results: Among 65 cases of combined liver-kidney transplantation, the success rate in the late 40 cases was 77.5%. The function of the grafted liver and kidney remained normal. Conclusion: This rat model of combined liver-kidney transplantation can be established in common laboratory conditions with high success rate and meet the needs of renal transplantation experiment.

  1. A joint calibration model for combining predictive distributions

    Directory of Open Access Journals (Sweden)

    Patrizia Agati

    2013-05-01

    Full Text Available In many research fields, as for example in probabilistic weather forecasting, valuable predictive information about a future random phenomenon may come from several, possibly heterogeneous, sources. Forecast combining methods have been developed over the years in order to deal with ensembles of sources: the aim is to combine several predictions in such a way to improve forecast accuracy and reduce risk of bad forecasts.In this context, we propose the use of a Bayesian approach to information combining, which consists in treating the predictive probability density functions (pdfs from the individual ensemble members as data in a Bayesian updating problem. The likelihood function is shown to be proportional to the product of the pdfs, adjusted by a joint “calibration function” describing the predicting skill of the sources (Morris, 1977. In this paper, after rephrasing Morris’ algorithm in a predictive context, we propose to model the calibration function in terms of bias, scale and correlation and to estimate its parameters according to the least squares criterion. The performance of our method is investigated and compared with that of Bayesian Model Averaging (Raftery, 2005 on simulated data.

  2. Combining microsimulation and spatial interaction models for retail location analysis

    Science.gov (United States)

    Nakaya, Tomoki; Fotheringham, A. Stewart; Hanaoka, Kazumasa; Clarke, Graham; Ballas, Dimitris; Yano, Keiji

    2007-12-01

    Although the disaggregation of consumers is crucial in understanding the fragmented markets that are dominant in many developed countries, it is not always straightforward to carry out such disaggregation within conventional retail modelling frameworks due to the limitations of data. In particular, consumer grouping based on sampled data is not assured to link with the other statistics that are vital in estimating sampling biases and missing variables in the sampling survey. To overcome this difficulty, we propose a useful combination of spatial interaction modelling and microsimulation approaches for the reliable estimation of retail interactions based on a sample survey of consumer behaviour being linked with other areal statistics. We demonstrate this approach by building an operational retail interaction model to estimate expenditure flows from households to retail stores in a local city in Japan, Kusatsu City.

  3. Modeling plasmonic scattering combined with thin-film optics.

    Science.gov (United States)

    Schmid, M; Klenk, R; Lux-Steiner, M Ch; Topic, M; Krc, J

    2011-01-14

    Plasmonic scattering from metal nanostructures presents a promising concept for improving the conversion efficiency of solar cells. The determination of optimal nanostructures and their position within the solar cell is crucial to boost the efficiency. Therefore we established a one-dimensional optical model combining plasmonic scattering and thin-film optics to simulate optical properties of thin-film solar cells including metal nanoparticles. Scattering models based on dipole oscillations and Mie theory are presented and their integration in thin-film semi-coherent optical descriptions is explained. A plasmonic layer is introduced in the thin-film structure to simulate scattering properties as well as parasitic absorption in the metal nanoparticles. A proof of modeling concept is given for the case of metal-island grown silver nanoparticles on glass and ZnO:Al/glass substrates. Using simulations a promising application of the nanoparticle integration is shown for the case of CuGaSe(2) solar cells.

  4. A finite-element model for healing of cutaneous wounds combining contraction, angiogenesis and closure

    NARCIS (Netherlands)

    Vermolen, F.J.; Javierre, E.

    2011-01-01

    A simplified finite-element model for wound healing is proposed. The model takes into account the sequential steps of dermal regeneration, wound contraction, angiogenesis and wound closure. An innovation in the present study is the combination of the aforementioned partially overlapping processes,

  5. A finite-element model for healing of cutaneous wounds combining contraction, angiogenesis and closure

    NARCIS (Netherlands)

    Vermolen, F.J.; Javierre, E.

    2011-01-01

    A simplified finite-element model for wound healing is proposed. The model takes into account the sequential steps of dermal regeneration, wound contraction, angiogenesis and wound closure. An innovation in the present study is the combination of the aforementioned partially overlapping processes, w

  6. Combining Wavelet Transform and Hidden Markov Models for ECG Segmentation

    Directory of Open Access Journals (Sweden)

    Jérôme Boudy

    2007-01-01

    Full Text Available This work aims at providing new insights on the electrocardiogram (ECG segmentation problem using wavelets. The wavelet transform has been originally combined with a hidden Markov models (HMMs framework in order to carry out beat segmentation and classification. A group of five continuous wavelet functions commonly used in ECG analysis has been implemented and compared using the same framework. All experiments were realized on the QT database, which is composed of a representative number of ambulatory recordings of several individuals and is supplied with manual labels made by a physician. Our main contribution relies on the consistent set of experiments performed. Moreover, the results obtained in terms of beat segmentation and premature ventricular beat (PVC detection are comparable to others works reported in the literature, independently of the type of the wavelet. Finally, through an original concept of combining two wavelet functions in the segmentation stage, we achieve our best performances.

  7. A New Segmentation Model--Combined Mumford-Shah Model with Narrow Band

    Institute of Scientific and Technical Information of China (English)

    Wang Zheng(王峥); Yang Xin; Shi Pengfei

    2004-01-01

    A segmentation model that combines the Mumford-Shah (M-S) model and narrow band scheme of level set is presented. The M-S model is a desirable model for image segmentation, but computationally time-consuming. This paper introduces a fast segmentation model, which combines the M-S model and narrow band scheme using new initialization method. The new initialization method is based on fast marching method, and the computing time is O(n). In each iteration step, the new segmentation model only deals with the data in narrow band instead of the whole image. Comparing M-S model and new narrow band M-S, experiments show that the two models can obtain almost the same segmentation result, but the computing time of new narrow band M-S model is much less than M-S model.

  8. Induction and Processing of the Radiation-Induced Gamma-H2AX Signal and Its Link to the Underlying Pattern of DSB: A Combined Experimental and Modelling Study.

    Science.gov (United States)

    Tommasino, Francesco; Friedrich, Thomas; Jakob, Burkhard; Meyer, Barbara; Durante, Marco; Scholz, Michael

    2015-01-01

    We present here an analysis of DSB induction and processing after irradiation with X-rays in an extended dose range based on the use of the γH2AX assay. The study was performed by quantitative flow cytometry measurements, since the use of foci counting would result in reasonable accuracy only in a limited dose range of a few Gy. The experimental data are complemented by a theoretical analysis based on the GLOBLE model. In fact, original aim of the study was to test GLOBLE predictions against new experimental data, in order to contribute to the validation of the model. Specifically, the γH2AX signal kinetics has been investigated up to 24 h after exposure to increasing photon doses between 2 and 500 Gy. The prolonged persistence of the signal at high doses strongly suggests dose dependence in DSB processing after low LET irradiation. Importantly, in the framework of our modelling analysis, this is related to a gradually increased fraction of DSB clustering at the micrometre scale. The parallel study of γH2AX dose response curves shows the onset of a pronounced saturation in two cell lines at a dose of about 20 Gy. This dose is much lower than expected according to model predictions based on the values usually adopted for the DSB induction yield (≈ 30 DSB/Gy) and for the γH2AX foci extension of approximately 2 Mbp around the DSB. We show and discuss how theoretical predictions and experimental findings can be in principle reconciled by combining an increased DSB induction yield with the assumption of a larger genomic extension for the single phosphorylated regions. As an alternative approach, we also considered in our model the possibility of a 3D spreading-mechanism of the H2AX phosphorylation around the induced DSB, and applied it to the analysis of both the aspects considered. Our results are found to be supportive for the basic assumptions on which GLOBLE is built. Apart from giving new insights into the H2AX phosphorylation process, experiments performed

  9. Study of the combined effect of temperature, pH and water activity on the radial growth rate of the white-rot basidiomycete Physisporinus vitreus by using a hyphal growth model

    CERN Document Server

    Fuhr, M J; Schubert, M; Schwarze, F W M R; Herrmann, H J

    2011-01-01

    The present work investigates environmental effects on the growth of fungal colonies of P. vitreus by using a lattice-free discrete modelling approach called FGM (Fuhr et al. (2010), arXiv:1101.1747), in which hyphae and nutrients are considered as discrete structures. A discrete modelling approach allows studying the underlying mechanistic rule concerning the basic architecture and dynamic of fungal networks on the scale of a single colony. By comparing simulations of the FGM with laboratory experiments of growing fungal colonies on malt extract agar we show that combined effect of temperature, pH and water activity on the radial growth rate of a fungal colony on a macroscopic scale may be explained by a power law for the growth costs of hyphal expansion on a microscopic scale. The information about the response of the fungal mycelium on a microscopic scale to environmental conditions is essential to simulate its behavior in complex structure substrates such as wood, where the impact of the fungus to the woo...

  10. BAYESIAN FORECASTS COMBINATION TO IMPROVE THE ROMANIAN INFLATION PREDICTIONS BASED ON ECONOMETRIC MODELS

    Directory of Open Access Journals (Sweden)

    Mihaela Simionescu

    2014-12-01

    Full Text Available There are many types of econometric models used in predicting the inflation rate, but in this study we used a Bayesian shrinkage combination approach. This methodology is used in order to improve the predictions accuracy by including information that is not captured by the econometric models. Therefore, experts’ forecasts are utilized as prior information, for Romania these predictions being provided by Institute for Economic Forecasting (Dobrescu macromodel, National Commission for Prognosis and European Commission. The empirical results for Romanian inflation show the superiority of a fixed effects model compared to other types of econometric models like VAR, Bayesian VAR, simultaneous equations model, dynamic model, log-linear model. The Bayesian combinations that used experts’ predictions as priors, when the shrinkage parameter tends to infinite, improved the accuracy of all forecasts based on individual models, outperforming also zero and equal weights predictions and naïve forecasts.

  11. Simulation of the Grazing Effects on Grassland Aboveground Net Primary Production Using DNDC Model Combined with Time-Series Remote Sensing Data—A Case Study in Zoige Plateau, China

    Directory of Open Access Journals (Sweden)

    Jiyan Wang

    2016-02-01

    Full Text Available Measuring the impact of livestock grazing on grassland above-ground net primary production (ANPP is essential for grass yield estimation and pasture management. However, since there is a lack of accurate and repeatable techniques to obtain the details of grazing locations and stocking rates at the regional scale, it is an extremely challenging task to study the influence of regional grazing on the grassland ANPP. Taking Zoige County as a case, this paper proposes an approach to quantify the spatial and temporal variation of grazing intensity and grazing period through time-series remote sensing data, simulated grassland ANPP through the denitrification and decomposition (DNDC model, and then explores the impact of grazing on grassland ANPP. The result showed that the model-estimated ANPP while considering grazing had a significant relationship with the field-observed ANPP, with the coefficient of determination (R2 of 0.75, root mean square error (RMSE of 122.86 kgC/ha, and average relative error (RE of 8.77%. On the contrary, if grazing activity was not considered in simulation, a large uncertainty was found when the model-estimated ANPP was compared with the field observation, showing R2 of 0.4, RMSE of 211.51 kgC/ha, and average RE of 32.5%. For the whole area of Zoige County in 2012, the statistics of the estimation showed that the total regional ANPP was up to 3.815 × 105 tC, while the total regional ANPP, without considering grazing, would be overestimated by 44.4%, up to 5.51 × 105 tC. This indicates that the grazing parameters derived in this study could effectively improve the accuracy of ANPP simulation results. Therefore, it is feasible to combine time-series remote sensing data with the process model to simulate the grazing effects on grassland ANPP. However, some issues, such as selecting proper remote sensing data, improving the quality of model input parameters, collecting more field data, and exploring the data assimilation

  12. Measurement and modeling of depth cue combination: in defense of weak fusion.

    Science.gov (United States)

    Landy, M S; Maloney, L T; Johnston, E B; Young, M

    1995-02-01

    Various visual cues provide information about depth and shape in a scene. When several of these cues are simultaneously available in a single location in the scene, the visual system attempts to combine them. In this paper, we discuss three key issues relevant to the experimental analysis of depth cue combination in human vision: cue promotion, dynamic weighting of cues, and robustness of cue combination. We review recent psychophysical studies of human depth cue combination in light of these issues. We organize the discussion and review as the development of a model of the depth cue combination process termed modified weak fusion (MWF). We relate the MWF framework to Bayesian theories of cue combination. We argue that the MWF model is consistent with previous experimental results and is a parsimonious summary of these results. While the MWF model is motivated by normative considerations, it is primarily intended to guide experimental analysis of depth cue combination in human vision. We describe experimental methods, analogous to perturbation analysis, that permit us to analyze depth cue combination in novel ways. In particular these methods allow us to investigate the key issues we have raised. We summarize recent experimental tests of the MWF framework that use these methods.

  13. A NEW COMBINED LOCAL AND NON-LOCAL PBL MODEL FOR METEOROLOGY AND AIR QUALITY MODELING

    Science.gov (United States)

    A new version of the Asymmetric Convective Model (ACM) has been developed to describe sub-grid vertical turbulent transport in both meteorology models and air quality models. The new version (ACM2) combines the non-local convective mixing of the original ACM with local eddy diff...

  14. A NEW COMBINED LOCAL AND NON-LOCAL PBL MODEL FOR METEOROLOGY AND AIR QUALITY MODELING

    Science.gov (United States)

    A new version of the Asymmetric Convective Model (ACM) has been developed to describe sub-grid vertical turbulent transport in both meteorology models and air quality models. The new version (ACM2) combines the non-local convective mixing of the original ACM with local eddy diff...

  15. Contribution of satellite laser ranging to combined gravity field models

    Science.gov (United States)

    Maier, A.; Krauss, S.; Hausleitner, W.; Baur, O.

    2012-02-01

    In the framework of satellite-only gravity field modeling, satellite laser ranging (SLR) data is typically exploited to recover long-wavelength features. This contribution provides a detailed discussion of the SLR component of GOCO02S, the latest release of combined models within the GOCO series. Over a period of five years (January 2006 to December 2010), observations to LAGEOS-1, LAGEOS-2, Ajisai, Stella, and Starlette were analyzed. We conducted a series of closed-loop simulations and found that estimating monthly sets of spherical harmonic coefficients beyond degree five leads to exceedingly ill-posed normal equation systems. Therefore, we adopted degree five as the spectral resolution for real data analysis. We compared our monthly coefficient estimates of degree two with SLR and Gravity Recovery and Climate Experiment (GRACE) time series provided by the Center for Space Research (CSR) at Austin, Texas. Significant deviations in C20 were noted between SLR and GRACE; the agreement is better for the non-zonal coefficients. Fitting sinusoids together with a linear trend to our C20 time series yielded a rate of (-1.75 ± 0.6) × 10-11/yr; this drift is equivalent to a geoid change from pole to equator of 0.35 ± 0.12 mm/yr or an apparent Greenland mass loss of 178.5 ± 61.2 km3/yr. The mean of all monthly solutions, averaged over the five-year period, served as input for the satellite-only model GOCO02S. The contribution of SLR to the combined gravity field model is highest for C20, and hence is essential for the determination of the Earth's oblateness.

  16. Dispersion modeling of selected PAHs in urban air: A new approach combining dispersion model with GIS and passive air sampling

    Science.gov (United States)

    Sáňka, Ondřej; Melymuk, Lisa; Čupr, Pavel; Dvorská, Alice; Klánová, Jana

    2014-10-01

    This study introduces a new combined air concentration measurement and modeling approach that we propose can be useful in medium and long term air quality assessment. A dispersion study was carried out for four high molecular weight polycyclic aromatic hydrocarbons (PAHs) in an urban area with industrial, traffic and domestic heating sources. A geographic information system (GIS) was used both for processing of input data as well as visualization of the modeling results. The outcomes of the dispersion model were compared to the results of passive air sampling (PAS). Despite discrepancies between measured and modeled concentrations, an approach combining the two techniques is promising for future air quality assessment. Differences between measured and modeled concentrations, in particular when measured values exceed the modeled concentrations, are indicative of undocumented, sporadic pollutant sources. Thus, these differences can also be useful for assessing and refining emission inventories.

  17. Efficacy of PTX3 and Posaconazole Combination in a Rat Model of Invasive Pulmonary Aspergillosis

    OpenAIRE

    Marra, Emanuele; Sousa, Vitor L.; Gaziano,Roberta; Pacello, M. Lucrezia; Arseni, Brunilde; Aurisicchio, Luigi; De Santis, Rita; Salvatori, Giovanni

    2014-01-01

    Posaconazole is currently used for the prophylaxis of invasive pulmonary aspergillosis (IPA). Limitations to posaconazole usage are drug-drug interactions and side effects. PTX3 is an innate immunity glycoprotein with opsonic activity, proven to be protective in IPA animal models. This study investigated the combination of posaconazole with PTX3. The results indicate synergy between PTX3 and posaconazole against aspergillosis, suggesting that a combination of reduced doses of posaconazole wit...

  18. Combining segmentation and attention: a new foveal attention model

    Directory of Open Access Journals (Sweden)

    Rebeca eMarfil

    2014-08-01

    Full Text Available Artificial vision systems cannot process all the information that they receive from the world in real time because it is highly expensive and inefficient in terms of computational cost. Inspired by biological perception systems, articial attention models pursuit to select only the relevant part of the scene. Besides, it is well established that the units of attention on human vision are not merely spatial but closely related to perceptual objects (proto-objects. This implies a strong bidirectional relationship between segmentation and attention processes. Therefore, while the segmentation process is the responsible to extract the proto-objects from the scene, attention can guide segmentation, arising the concept of foveal attention. When the focus of attention is deployed from one visual unit to another, the rest of the scene is perceived but at a lower resolution that the focused object. The result is a multi-resolution visual perception in which the fovea, a dimple on the central retina, provides the highest resolution vision. In this paper, a bottom-up foveal attention model is presented. In this model the input image is a foveal image represented using a Cartesian Foveal Geometry (CFG, which encodes the field of view of the sensor as a fovea (placed in the focus of attention surrounded by a set of concentric rings with decreasing resolution. Then multirresolution perceptual segmentation is performed by building a foveal polygon using the Bounded Irregular Pyramid (BIP. Bottom-up attention is enclosed in the same structure, allowing to set the fovea over the most salient image proto-object. Saliency is computed as a linear combination of multiple low level features such us colour and intensity contrast, symmetry, orientation and roundness. Obtained results from natural images show that the performance of the combination of hierarchical foveal segmentation and saliency estimation is good in terms of accuracy and speed.

  19. Electricity Price Forecast Using Combined Models with Adaptive Weights Selected and Errors Calibrated by Hidden Markov Model

    Directory of Open Access Journals (Sweden)

    Da Liu

    2013-01-01

    Full Text Available A combined forecast with weights adaptively selected and errors calibrated by Hidden Markov model (HMM is proposed to model the day-ahead electricity price. Firstly several single models were built to forecast the electricity price separately. Then the validation errors from every individual model were transformed into two discrete sequences: an emission sequence and a state sequence to build the HMM, obtaining a transmission matrix and an emission matrix, representing the forecasting ability state of the individual models. The combining weights of the individual models were decided by the state transmission matrixes in HMM and the best predict sample ratio of each individual among all the models in the validation set. The individual forecasts were averaged to get the combining forecast with the weights obtained above. The residuals of combining forecast were calibrated by the possible error calculated by the emission matrix of HMM. A case study of day-ahead electricity market of Pennsylvania-New Jersey-Maryland (PJM, USA, suggests that the proposed method outperforms individual techniques of price forecasting, such as support vector machine (SVM, generalized regression neural networks (GRNN, day-ahead modeling, and self-organized map (SOM similar days modeling.

  20. Study on effective parameter of the triple-pressure reheat combined cycle performance

    OpenAIRE

    Ibrahim Thamir K.; Rahman M.M.

    2013-01-01

    The thermodynamic analyses of the triple-pressure reheat combined cycle gas turbines with duct burner are presented and discussed in this paper. The overall performance of a combined cycle gas turbine power plant is influenced by the ambient temperature, compression ratio and turbine inlet temperature. These parameters affect the overall thermal efficiency, power output and the heat-rate. In this study a thermodynamic model was development on an existing actual combined cycle gas turbin...

  1. A combined Preisach–Hyperbolic Tangent model for magnetic hysteresis of Terfenol-D

    Energy Technology Data Exchange (ETDEWEB)

    Talebian, Soheil [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Hojjat, Yousef, E-mail: yhojjat@modares.ac.ir [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Ghodsi, Mojtaba [Department of Mechanical and Industrial Engineering, Sultan Qaboos University, Muscat (Oman); Karafi, Mohammad Reza [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Mirzamohammadi, Shahed [Department of Mechanical Engineering, Shahid Rajaee University, Tehran (Iran, Islamic Republic of)

    2015-12-15

    This study presents a new model using the combination of Preisach and Hyperbolic Tangent models, to predict the magnetic hysteresis of Terfenol-D at different frequencies. Initially, a proper experimental setup was fabricated and used to obtain different magnetic hysteresis curves of Terfenol-D; such as major, minor and reversal loops. Then, it was shown that the Hyperbolic Tangent model is precisely capable of modeling the magnetic hysteresis of the Terfenol-D for both rate-independent and rate-dependent cases. Empirical equations were proposed with respect to magnetic field frequency which can calculate the non-dimensional coefficients needed by the model. These empirical equations were validated at new frequencies of 100 Hz and 300 Hz. Finally, the new model was developed through the combination of Preisach and Hyperbolic Tangent models. In the combined model, analytical relations of the Hyperbolic Tangent model for the first order reversal loops determined the weighting function of the Preisach model. This model reduces the required experiments and errors due to numerical differentiations generally needed for characterization of the Preisach function. In addition, it can predict the rate-dependent hysteresis as well as rate-independent hysteresis. - Highlights: • Different hysteresis curves of Terfenol-D are experimentally obtained at 0–200 Hz. • A new model is presented using combination of Preisach and Hyperbolic Tangent models. • The model predicts both rate-independent and rate-dependent hystereses of Terfenol-D. • The analytical model reduces the numerical errors and number of required experiments.

  2. Combining bifurcation and sensitivity analysis for ecological models. Model analysis, and the allegory of the caveEcological Dynamics

    Science.gov (United States)

    van Voorn, George A. K.; Kooi, Bob W.

    2017-06-01

    Plato's well-known allegory of the cave describes an observer chained in a cave facing a blank wall on which shadows are projected of objects that are outside the cave. Only by breaking free from the chains can the observer submerge from the cave to see what the objects really look like. Ecological model features compare to the objects outside the cave in this allegory. By performing model analysis light is shed on these features, creating projections that researchers can see. Model analysis methodologies like bifurcation analysis and sensitivity analysis each focus on particular model features and thus allow researchers to uncover only part of the model behaviour. By combining methodologies for model analysis possibilities arise for unravelling more of the model's behaviour, allowing researchers to `break free'. In this paper benefits and issues of combining model analysis methodologies are discussed using a case study. The case study involves three representations of the well-known Rosenzweig-MacArthur predator-prey model, namely the usual one where state variables and parameters have dimensions, a dimensionless representation, and a generalized representation. Based on the results we argue that researchers should combine bifurcation and sensitivity analysis methodologies when analyzing ecological models.

  3. Prediction of Combine Economic Life Based on Repair and Maintenance Costs Model

    Directory of Open Access Journals (Sweden)

    A Rohani

    2014-09-01

    Full Text Available Farm machinery managers often need to make complex economic decisions on machinery replacement. Repair and maintenance costs can have significant impacts on this economic decision. The farm manager must be able to predict farm machinery repair and maintenance costs. This study aimed to identify a regression model that can adequately represent the repair and maintenance costs in terms of machine age in cumulative hours of use. The regression model has the ability to predict the repair and maintenance costs for longer time periods. Therefore, it can be used for the estimation of the economic life. The study was conducted using field data collected from 11 John-Deer 955 combine harvesters used in several western provinces of Iran. It was found that power model has a better performance for the prediction of combine repair and maintenance costs. The results showed that the optimum replacement age of John-Deer 955 combine was 54300 cumulative hours.

  4. Model Predictive Control of Integrated Gasification Combined Cycle Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    B. Wayne Bequette; Priyadarshi Mahapatra

    2010-08-31

    The primary project objectives were to understand how the process design of an integrated gasification combined cycle (IGCC) power plant affects the dynamic operability and controllability of the process. Steady-state and dynamic simulation models were developed to predict the process behavior during typical transients that occur in plant operation. Advanced control strategies were developed to improve the ability of the process to follow changes in the power load demand, and to improve performance during transitions between power levels. Another objective of the proposed work was to educate graduate and undergraduate students in the application of process systems and control to coal technology. Educational materials were developed for use in engineering courses to further broaden this exposure to many students. ASPENTECH software was used to perform steady-state and dynamic simulations of an IGCC power plant. Linear systems analysis techniques were used to assess the steady-state and dynamic operability of the power plant under various plant operating conditions. Model predictive control (MPC) strategies were developed to improve the dynamic operation of the power plants. MATLAB and SIMULINK software were used for systems analysis and control system design, and the SIMULINK functionality in ASPEN DYNAMICS was used to test the control strategies on the simulated process. Project funds were used to support a Ph.D. student to receive education and training in coal technology and the application of modeling and simulation techniques.

  5. Combining multiblock and detailed fluid flow models (LOVI) - MASIT17

    Energy Technology Data Exchange (ETDEWEB)

    Alopaeus, V.; Moilanen, P.; Visuri, O.; Laakkonen, M.; Aittamaa, J. (Helsinki University of Technology, Faculty of Chemistry and Materials Sciences, Department of Biotechnology and Chemical Technology, Espoo (Finland)); Heiskanen, K.; Wierink, G. (Helsinki University of Technology, Faculty of Chemistry and Materials Sciences, Department of Materials Science and Engineering, Espoo (Finland)); Manninen, M.; Seppaelae, M. (VTT Technical Research Centre of Finland, Espoo (Finland))

    2008-07-01

    The goal of this research project is to develop models for scale-up, design and operation of heterogeneous reactors. By computing a detailed fluid flow field and using it in a multiblock-model the computing times can be kept reasonable. Our modelling is based on phenomenological models verified on experimental results. Several experimental apparatuses have been used to study gas-liquid flow (tapered channel, 14/200dm3 stirred vessels and the 'giraffe') and bubble-particle interactions. A particle imaging velocimetry (PIV) apparatus is being purchased during 2008 to study fluid flow fields. There has been extensive experimental activity. During this project phenomenological models have been verified, numerical methods for the calculation of population balances have been improved, a novel local mixing time analysis method has been developed and automated multiblock generation algorithms have been developed. A method of evaluating CFD results with a single glance with a two-block model has been introduced. Fermentation process of Galilaeus and the flotation cell of Outotec have been modelled. (orig.)

  6. Combined Hand Gesture — Speech Model for Human Action Recognition

    Directory of Open Access Journals (Sweden)

    Sheng-Tzong Cheng

    2013-12-01

    Full Text Available This study proposes a dynamic hand gesture detection technology to effectively detect dynamic hand gesture areas, and a hand gesture recognition technology to improve the dynamic hand gesture recognition rate. Meanwhile, the corresponding relationship between state sequences in hand gesture and speech models is considered by integrating speech recognition technology with a multimodal model, thus improving the accuracy of human behavior recognition. The experimental results proved that the proposed method can effectively improve human behavior recognition accuracy and the feasibility of system applications. Experimental results verified that the multimodal gesture-speech model provided superior accuracy when compared to the single modal versions.

  7. Combined hand gesture--speech model for human action recognition.

    Science.gov (United States)

    Cheng, Sheng-Tzong; Hsu, Chih-Wei; Li, Jian-Pan

    2013-12-12

    This study proposes a dynamic hand gesture detection technology to effectively detect dynamic hand gesture areas, and a hand gesture recognition technology to improve the dynamic hand gesture recognition rate. Meanwhile, the corresponding relationship between state sequences in hand gesture and speech models is considered by integrating speech recognition technology with a multimodal model, thus improving the accuracy of human behavior recognition. The experimental results proved that the proposed method can effectively improve human behavior recognition accuracy and the feasibility of system applications. Experimental results verified that the multimodal gesture-speech model provided superior accuracy when compared to the single modal versions.

  8. Education Knowledge System Combination Model Based on the Components

    Institute of Scientific and Technical Information of China (English)

    CHEN Lei; LI Dehua; LI Xiaojian; WU Chunxiang

    2007-01-01

    Resources are the base and core of education information, but current web education resources have no structure and it is still difficult to reuse them and make them can be self assembled and developed continually. According to the knowledge structure of course and text, the relation among knowledge points, knowledge units from three levels of media material, we can build education resource components, and build TKCM (Teaching Knowledge Combination Model) based on resource components. Builders can build and assemble knowledge system structure and make knowledge units can be self assembled, thus we can develop and consummate them continually. Users can make knowledge units can be self assembled and renewed, and build education knowledge system to satisfy users' demand under the form of education knowledge system.

  9. Multistrain models predict sequential multidrug treatment strategies to result in less antimicrobial resistance than combination treatment

    DEFF Research Database (Denmark)

    Ahmad, Amais; Zachariasen, Camilla; Christiansen, Lasse Engbo;

    2016-01-01

    considered combination treatments. The current study modeled bacterial growth in the intestine of pigs after intramuscular combination treatment (i.e. using two antibiotics simultaneously) and sequential treatments (i.e. alternating between two antibiotics) in order to identify the factors that favor...... the sensitive fraction of the commensal flora.Growth parameters for competing bacterial strains were estimated from the combined in vitro pharmacodynamic effect of two antimicrobials using the relationship between concentration and net bacterial growth rate. Predictions of in vivo bacterial growth were...

  10. The Optimal Linear Combination of Multiple Predictors Under the Generalized Linear Models.

    Science.gov (United States)

    Jin, Hua; Lu, Ying

    2009-11-15

    Multiple alternative diagnostic tests for one disease are commonly available to clinicians. It's important to use all the good diagnostic predictors simultaneously to establish a new predictor with higher statistical utility. Under the generalized linear model for binary outcomes, the linear combination of multiple predictors in the link function is proved optimal in the sense that the area under the receiver operating characteristic (ROC) curve of this combination is the largest among all possible linear combination. The result was applied to analysis of the data from the Study of Osteoporotic Fractures (SOF) with comparison to Su and Liu's approach.

  11. ENSO and annual cycle interaction: the combination mode representation in CMIP5 models

    Science.gov (United States)

    Ren, Hong-Li; Zuo, Jinqing; Jin, Fei-Fei; Stuecker, Malte F.

    2016-06-01

    Recent research demonstrated the existence of a combination mode (C-mode) originating from the atmospheric nonlinear interaction between the El Niño-Southern Oscillation (ENSO) and the Pacific warm pool annual cycle. In this paper, we show that the majority of coupled climate models in the Coupled Model Intercomparison Project Phase 5 (CMIP5) are able to reproduce the observed spatial pattern of the C-mode in terms of surface wind anomalies reasonably well, and about half of the coupled models are able to reproduce spectral power at the combination tone periodicities of about 10 and/or 15 months. Compared to the CMIP5 historical simulations, the CMIP5 Atmospheric Model Intercomparison Project (AMIP) simulations can generally exhibit a more realistic simulation of the C-mode due to prescribed lower boundary forcing. Overall, the multi-model ensemble average of the CMIP5 models tends to capture the C-mode better than the individual models. Furthermore, the models with better performance in simulating the ENSO mode tend to also exhibit a more realistic C-mode with respect to its spatial pattern and amplitude, in both the CMIP5 historical and AMIP simulations. This study shows that the CMIP5 models are able to simulate the proposed combination mode mechanism to some degree, resulting from their reasonable performance in representing the ENSO mode. It is suggested that the main ENSO periods in the current climate models needs to be further improved for making the C-mode better.

  12. Combining models and measurements for European scale exceedance mapping

    Science.gov (United States)

    Denby, B.; Horálek, J.; Kurfürst, P.; de Smet, P.; de Leeuw, F.

    2009-04-01

    There is a need at the European policy and management level to have access to comprehensive assessments of air quality on the European scale. In support of this need the European Topic Centre for Air Quality and Climate Change carries out, on behalf of the European Environmental Agency, a range of European scale air quality mapping activities. In this paper statistical interpolation techniques have been applied to map and assess the rural background concentrations of PM10 and ozone on a daily basis over all of Europe. These daily maps are further used to determine exceedances of the air quality directive limit values for annual and daily mean PM10 as well as the percentile (26'th highest) 8 hour running mean for ozone. The maps are created using multiple linear regression of both the LOTOS-EUROS and EMEP chemical transport models along with daily air quality data taken from Airbase. Residual kriging of the regression fields is then applied for the final maps. Comparisons are made when using different models, different interpolation methods and when using annual instead of daily statistics. In addition to the assessment maps attention is also given to estimating the uncertainty of the maps. The methodology for determining the uncertainty in exceedances is described and maps of the uncertainty, along with probability of exceedance maps, are provided. By the use of cross-validation methods the quality of the maps is assessed. The results show that models alone do not provide useful assessment maps of exceedances for either PM10 or ozone. When used in combination with measurements both of the models give similar levels of uncertainty. The uncertainty is, in almost all cases, reduced when daily maps are used to determine exceedances rather than the use of annual statistics.

  13. A Hierarchical Generalized Linear Model in Combination with Dispersion Modeling to Improve Sib-Pair Linkage Analysis.

    Science.gov (United States)

    Lee, Woojoo; Kim, Jeonghwan; Lee, Youngjo; Park, Taesung; Suh, Young Ju

    2015-01-01

    We explored a hierarchical generalized linear model (HGLM) in combination with dispersion modeling to improve the sib-pair linkage analysis based on the revised Haseman-Elston regression model for a quantitative trait. A dispersion modeling technique was investigated for sib-pair linkage analysis using simulation studies and real data applications. We considered 4 heterogeneous dispersion settings according to a signal-to-noise ratio (SNR) in the various statistical models based on the Haseman-Elston regression model. Our numerical studies demonstrated that susceptibility loci could be detected well by modeling the dispersion parameter appropriately. In particular, the HGLM had better performance than the linear regression model and the ordinary linear mixed model when the SNR is low, i.e., when substantial noise was present in the data. The study shows that the HGLM in combination with dispersion modeling can be utilized to identify multiple markers showing linkage to familial complex traits accurately. Appropriate dispersion modeling might be more powerful to identify markers closest to the major genes which determine a quantitative trait. © 2015 S. Karger AG, Basel.

  14. Efficient pan-European river flood hazard modelling through a combination of statistical and physical models

    Science.gov (United States)

    Paprotny, Dominik; Morales-Nápoles, Oswaldo; Jonkman, Sebastiaan N.

    2017-07-01

    Flood hazard is currently being researched on continental and global scales, using models of increasing complexity. In this paper we investigate a different, simplified approach, which combines statistical and physical models in place of conventional rainfall-run-off models to carry out flood mapping for Europe. A Bayesian-network-based model built in a previous study is employed to generate return-period flow rates in European rivers with a catchment area larger than 100 km2. The simulations are performed using a one-dimensional steady-state hydraulic model and the results are post-processed using Geographical Information System (GIS) software in order to derive flood zones. This approach is validated by comparison with Joint Research Centre's (JRC) pan-European map and five local flood studies from different countries. Overall, the two approaches show a similar performance in recreating flood zones of local maps. The simplified approach achieved a similar level of accuracy, while substantially reducing the computational time. The paper also presents the aggregated results on the flood hazard in Europe, including future projections. We find relatively small changes in flood hazard, i.e. an increase of flood zones area by 2-4 % by the end of the century compared to the historical scenario. However, when current flood protection standards are taken into account, the flood-prone area increases substantially in the future (28-38 % for a 100-year return period). This is because in many parts of Europe river discharge with the same return period is projected to increase in the future, thus making the protection standards insufficient.

  15. Combining Wireless Sensor Networks and Groundwater Transport Models: Protocol and Model Development in a Simulative Environment

    Science.gov (United States)

    Barnhart, K.; Urteaga, I.; Han, Q.; Porta, L.; Jayasumana, A.; Illangasekare, T.

    2007-12-01

    Groundwater transport modeling is intended to aid in remediation processes by providing prediction of plume location and by helping to bridge data gaps in the typically undersampled subsurface environment. Increased availability of computer resources has made computer-based transport models almost ubiquitous in calculating health risks, determining cleanup strategies, guiding environmental regulatory policy, and in determining culpable parties in lawsuits. Despite their broad use, very few studies exist which verify model correctness or even usefulness, and those that have shown significant discrepancies between predicted and actual results. Better predictions can only be gained from additional and higher quality data, but this is an expensive proposition using current sampling techniques. A promising technology is the use of wireless sensor networks (WSNs) which are comprised of wireless nodes (motes) coupled to in-situ sensors that are capable of measuring hydrological parameters. As the motes are typically battery powered, power consumption is a major concern in routing algorithms. By supplying predictions about the direction and arrival time of the contaminant, the application-driven routing protocol would then become more efficient. A symbiotic relationship then exists between the WSN, which is supplying the data to calibrate the transport model, and the model, which may be supplying predictive information to the WSN for optimum monitoring performance. Many challenges exist before the above can be realized: WSN protocols must mature, as must sensor technology, and inverse models and tools must be developed for integration into the system. As current model calibration, even automatic calibration, still often requires manual tweaking of calibration parameters, implementing this in a real-time closed-loop process may require significant work. Based on insights from a previous proof-of-concept intermediate-scale tank experiment, we are developing the models, tools

  16. Combining fire and erosion modeling to target forest management activities

    Science.gov (United States)

    William J. Elliot; Mary Ellen Miller; Nic Enstice

    2015-01-01

    Forests deliver a number of important ecosystem services including clean water. When forests are disturbed by wildfire, the timing, quantity and quality of runoff are altered. A modeling study was carried out in a forested watershed in California to determine the risk of wildfire, and the potential post-fire sediment delivery from approximately 6-ha hillslope polygons...

  17. COMBINING SOURCES IN STABLE ISOTOPE MIXING MODELS: ALTERNATIVE METHODS

    Science.gov (United States)

    Stable isotope mixing models are often used to quantify source contributions to a mixture. Examples include pollution source identification; trophic web studies; analysis of water sources for soils, plants, or water bodies; and many others. A common problem is having too many s...

  18. Combining Work and Study by Russian Higher Education Institution Students

    OpenAIRE

    Sergey Roshchin; Victor Rudakov

    2014-01-01

    Sergey Roshchin - Candidate of Science, Associate Professor, Prorector, Head of the Subdepartment of Labour and Population Economics, Director of the Laboratory for Labor Market Studies, National Research University - Higher School of Economics. E-mail: Rudakov - Analyst, Laboratory for Labor Market Studies, National Research University - Higher School of Economics. E-mail: Address: 26 Shabolovka str., Moscow, 119049, Russian Federation.Combin...

  19. Population pharmacokinetic modelling of morphine, gabapentin and their combination in the rat

    DEFF Research Database (Denmark)

    Papathanasiou, Theodoros; Juul, Rasmus Vestergaard; Gabel-Jensen, Charlotte

    2016-01-01

    Purpose The combination of morphine and gabapentin seems promising for the treatment of postoperative and neuropathic pain. Despite the well characterised pharmacodynamic interaction, little is known about possible pharmacokinetic interactions. The aim of this study was to evaluate whether co......-administration of the two drugs leads to modifications of their pharmacokinetic profiles. Methods The pharmacokinetics of morphine, morphine-3-glucuronide and gabapentin were characterised in rats following subcutaneous injections of morphine, gabapentin or their combination. Non-linear mixed effects modelling was applied...... and gabapentin bioavailability. Enterohepatic circulation of morphine-3-glucuronide was modelled using an oscillatory model. The combination did not lead to pharmacokinetic interactions for morphine or gabapentin but resulted in an estimated ~33% diminished morphine-3-glucuronide formation. Conclusions...

  20. Long-term runoff forecasting by combining hydrological models and meteorological records

    Science.gov (United States)

    Yang, Tao-Chang; Yu, Pao-Shan; Chen, Chiang-Chi

    2005-06-01

    Reservoir operation is generally based on the inflows of the upstream catchment of the reservoir. If the arriving inflows can be forecasted, that can benefit reservoir operation and management. This study attempts to construct a long-term inflow-forecasting model by combining a continuous rainfall-runoff model with the long-term weather outlook from the Central Weather Bureau of Taiwan. The analytical results demonstrate that the continuous rainfall-runoff model has good inflow simulation performance by using 10-day meteorological and inflow records over a 33-year period for model calibration and verification. The long-term inflow forecasting during the dry season was further conducted by combining the continuous rainfall-runoff model and the long-term weather outlook, which was found to have good performance.

  1. Modelling a Combined Heat and Power Plant based on Gasification, Micro Gas Turbine and Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Bang-Møller, Christian; Rokni, Masoud

    2009-01-01

    A system level modelling study on two combined heat and power (CHP) systems both based on biomass gasification. One system converts the product gas in a micro gas turbine (MGT) and the other in a combined solid oxide fuel cell (SOFC) and MGT arrangement. An electrochemical model of the SOFC has...

  2. Modelling a Combined Heat and Power Plant based on Gasification, Micro Gas Turbine and Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Bang-Møller, Christian; Rokni, Masoud

    2009-01-01

    A system level modelling study on two combined heat and power (CHP) systems both based on biomass gasification. One system converts the product gas in a micro gas turbine (MGT) and the other in a combined solid oxide fuel cell (SOFC) and MGT arrangement. An electrochemical model of the SOFC has...

  3. Estimating Net Primary Production of Swedish Forest Landscapes by Combining Mechanistic Modeling and Remote Sensing

    DEFF Research Database (Denmark)

    Tagesson, Håkan Torbern; Smith, Benjamin; Løfgren, Anders;

    2009-01-01

    The aim of this study was to investigate a combination of satellite images of leaf area index (LAI) with processbased vegetation modeling for the accurate assessment of the carbon balances of Swedish forest ecosystems at the scale of a landscape. Monthly climatologic data were used as inputs in a...

  4. Combined rock-physical modelling and seismic inversion techniques for characterisation of stacked sandstone reservoir

    NARCIS (Netherlands)

    Justiniano, A.; Jaya, Y.; Diephuis, G.; Veenhof, R.; Pringle, T.

    2015-01-01

    The objective of the study is to characterise the Triassic massive stacked sandstone deposits of the Main Buntsandstein Subgroup at Block Q16 located in the West Netherlands Basin. The characterisation was carried out through combining rock-physics modelling and seismic inversion techniques. The app

  5. Combining crop modelling with economic risk analysis for the evaluation of crop management strategies

    NARCIS (Netherlands)

    Lansigan, F.P.; Pandey, S.; Bouman, B.A.M.

    1997-01-01

    An agro-ecological approach is presented for the evaluation of alternative management options for rice production in the light of farmers attitudes towards risk. The approach combined eco-physiological crop growth modelling with stochastic dominance theory and is illustrated for a case study of rain

  6. Combined rock-physical modelling and seismic inversion techniques for characterisation of stacked sandstone reservoir

    NARCIS (Netherlands)

    Justiniano, A.; Jaya, Y.; Diephuis, G.; Veenhof, R.; Pringle, T.

    2015-01-01

    The objective of the study is to characterise the Triassic massive stacked sandstone deposits of the Main Buntsandstein Subgroup at Block Q16 located in the West Netherlands Basin. The characterisation was carried out through combining rock-physics modelling and seismic inversion techniques. The app

  7. Combined Rock-physical Modelling and Seismic Inversion Techniques for Characterisation of the Posidonia Shale Formation

    NARCIS (Netherlands)

    Justiniano, A.; Jaya, M.; Diephuis, G.

    2015-01-01

    The objective of this study is to characterise the Jurassic Posidonia Shale Formation at Block Q16 located in the West Netherlands Basin. The characterisation was carried out through combining rock-physics modelling and seismic inversion techniques. The results show that the Posidonia Shale Formatio

  8. A Hybrid Approach to Combine Physically Based and Data-Driven Models in Simulating Sediment Transportation

    NARCIS (Netherlands)

    Sewagudde, S.

    2008-01-01

    The objective of this study is to develop a methodology for hybrid modelling of sedimentation in a coastal basin or large shallow lake where physically based and data driven approaches are combined. This research was broken down into three blocks. The first block explores the possibility of approxim

  9. Combining FMEA with DEMATEL models to solve production process problems.

    Science.gov (United States)

    Tsai, Sang-Bing; Zhou, Jie; Gao, Yang; Wang, Jiangtao; Li, Guodong; Zheng, Yuxiang; Ren, Peng; Xu, Wei

    2017-01-01

    Failure mode and effects analysis (FMEA) is an analysis tool for identifying and preventing flaws or defects in products during the design and process planning stage, preventing the repeated occurrence of problems, reducing the effects of these problems, enhancing product quality and reliability, saving costs, and improving competitiveness. However, FMEA can only analyze one influence factor according to its priority, rendering this method ineffective for systems containing multiple FMs whose effects are simultaneous or interact with one another. Accordingly, when FMEA fails to identify the influence factors and the factors being influenced, the most crucial problems may be placed in lower priority or remain unresolved. Decision-Making Trial and Evaluation Laboratory (DEMATEL) facilitates the determination of cause and effect factors; by identifying the causal factors that should be prioritized, prompt and effective solutions to core problems can be derived, thereby enhancing performance. Using the photovoltaic cell manufacturing industry in China as the research target, the present study combined FMEA with DEMATEL to amend the flaws of FMEA and enhance its effectiveness. First, FMEA was used to identify items requiring improvement. Then, DEMATEL was employed to examine the interactive effects and causal relationships of these items. Finally, the solutions to the problems were prioritized. The proposed method effectively combined the advantages of FMEA and DEMATEL to facilitate the identification of core problems and prioritization of solutions in the Chinese photovoltaic cell industry.

  10. Performance Study of OBS Combined Node via Mixed Loss Delay Queueing Systems

    Directory of Open Access Journals (Sweden)

    Muhammad Faisal Hayat

    2014-01-01

    Full Text Available In this paper, we present a performance study of OBS (Optical Burst Switched combined node via mixed loss delay queueing models. In an OBS network, a node combining both edge and core switching functions multiplex the local traffic with the transit traffic on the output wavelengths channels. To control the channel sharing, strategies are proposed and analyzed in this study by extending the basic mixed loss delay queueing models. The presented models are solved by Markov chain techniques and the results are compared, and where necessary also supported, by the simulations of an OBS node implemented in detail

  11. Combining multimedia models with integrated urban water system models for micropollutants

    DEFF Research Database (Denmark)

    De Keyser, W.; Gevaert, V.; Verdonck, F.;

    2009-01-01

    and a stormwater infiltration pond scenario, as an example of a sustainable urban drainage system (SUDS). A case for Bis(2-ethylhexyl) phthalate (DEHP) was simulated and resulted in a reduced surface water concentration for the latter scenario. However, the model also showed that this was at the expense......Integrated urban water system (IUWS) modelling aims at assessing the quality of the surface water receiving the urban emissions through sewage treatment plants, combined sewer overflows (CSOs) and stormwater drainage systems. However, some micropollutants have the tendency to occur in more than one...... environmental medium. In this work, a multimedia fate and transport model (MFTM) is “wrapped around” a dynamic IUWS model for organic micropollutants to enable integrated environmental assessment. The combined model was tested on a hypothetical catchment using two scenarios: a reference scenario...

  12. Key Characteristics of Combined Accident including TLOFW accident for PSA Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bo Gyung; Kang, Hyun Gook [KAIST, Daejeon (Korea, Republic of); Yoon, Ho Joon [Khalifa University of Science, Technology and Research, Abu Dhabi (United Arab Emirates)

    2015-05-15

    The conventional PSA techniques cannot adequately evaluate all events. The conventional PSA models usually focus on single internal events such as DBAs, the external hazards such as fire, seismic. However, the Fukushima accident of Japan in 2011 reveals that very rare event is necessary to be considered in the PSA model to prevent the radioactive release to environment caused by poor treatment based on lack of the information, and to improve the emergency operation procedure. Especially, the results from PSA can be used to decision making for regulators. Moreover, designers can consider the weakness of plant safety based on the quantified results and understand accident sequence based on human actions and system availability. This study is for PSA modeling of combined accidents including total loss of feedwater (TLOFW) accident. The TLOFW accident is a representative accident involving the failure of cooling through secondary side. If the amount of heat transfer is not enough due to the failure of secondary side, the heat will be accumulated to the primary side by continuous core decay heat. Transients with loss of feedwater include total loss of feedwater accident, loss of condenser vacuum accident, and closure of all MSIVs. When residual heat removal by the secondary side is terminated, the safety injection into the RCS with direct primary depressurization would provide alternative heat removal. This operation is called feed and bleed (F and B) operation. Combined accidents including TLOFW accident are very rare event and partially considered in conventional PSA model. Since the necessity of F and B operation is related to plant conditions, the PSA modeling for combined accidents including TLOFW accident is necessary to identify the design and operational vulnerabilities.The PSA is significant to assess the risk of NPPs, and to identify the design and operational vulnerabilities. Even though the combined accident is very rare event, the consequence of combined

  13. Europlanet/IDIS: Combining Diverse Planetary Observations and Models

    Science.gov (United States)

    Schmidt, Walter; Capria, Maria Teresa; Chanteur, Gerard

    2013-04-01

    Planetary research involves a diversity of research fields from astrophysics and plasma physics to atmospheric physics, climatology, spectroscopy and surface imaging. Data from all these disciplines are collected from various space-borne platforms or telescopes, supported by modelling teams and laboratory work. In order to interpret one set of data often supporting data from different disciplines and other missions are needed while the scientist does not always have the detailed expertise to access and utilize these observations. The Integrated and Distributed Information System (IDIS) [1], developed in the framework of the Europlanet-RI project, implements a Virtual Observatory approach ([2] and [3]), where different data sets, stored in archives around the world and in different formats, are accessed, re-formatted and combined to meet the user's requirements without the need of familiarizing oneself with the different technical details. While observational astrophysical data from different observatories could already earlier be accessed via Virtual Observatories, this concept is now extended to diverse planetary data and related model data sets, spectral data bases etc. A dedicated XML-based Europlanet Data Model (EPN-DM) [4] was developed based on data models from the planetary science community and the Virtual Observatory approach. A dedicated editor simplifies the registration of new resources. As the EPN-DM is a super-set of existing data models existing archives as well as new spectroscopic or chemical data bases for the interpretation of atmospheric or surface observations, or even modeling facilities at research institutes in Europe or Russia can be easily integrated and accessed via a Table Access Protocol (EPN-TAP) [5] adapted from the corresponding protocol of the International Virtual Observatory Alliance [6] (IVOA-TAP). EPN-TAP allows to search catalogues, retrieve data and make them available through standard IVOA tools if the access to the archive

  14. A Decision Support Systems Using A Combined Dynamic Model For Integrated Watershed Management

    Science.gov (United States)

    Kudo, E.; Ostrowski, M.

    In this context A Decision Support System (DSS) is presented using a combined dy- namic model for Integrated Watershed Management (IWM) in a small urbanized basin in Japan. In order to improve today's often unsustainable watershed management, the causes of water problems, which interact with each other, must be identified and adequate actions must be chosen to solve the problems. To achieve the ultimate goal of sustain- able development (SD) for water it is essential to develop and apply generic DSSs. A DSS is frequently defined as a combination of a management information system, a model base and an evaluation / assessment module. The EU Water Framework Di- rectives recently established have a narrow time schedule requiring fast action into this direction, which does hardly allow to develop completely new tolls. Thus we are trying to combine different existing dynamic models that incorporate an urban man- agement model, a water quality analysis model, a groundwater analysis model and a water supply model including geographical information system data. With this com- bined model, the most appropriate and sustainable water management plan in an urban area will be developed while considering land use, ground water level, allocation of drainage system, sewerage, water supply works, water quality, and quantity. Because of sharing input data, using this combined model requires less data than using sev- eral separate models. The DSS can also be used to determine the optimum location of gages and monitoring sites. As a case study, the research will deal with the Taguri-river basin in Japan. This basin is located near Tokyo. Although the area in this basin has about 8 km2 only, there are densely build-up areas, paddy fields, and non-developed areas. The river is polluted due to wastewater from point resources: households, and non-point resources: roads and fields, etc. Overpumping of aquifers results in sinking groundwater tables and land subsidence. Moreover, a decrease

  15. 构建基于工学结合的多技能教育模式的分析%Analysis of the Construction of Multi-skilled Education Model Based on the Combination of Work and Study

    Institute of Scientific and Technical Information of China (English)

    丁为斌

    2011-01-01

    工学结合在提高高职业院校毕业生职业技能的同时也暴露了在就业岗位等方面“窄化”了,为了提高高职毕业生的多方面的就业技能,就需要构建以工学结合为基础的多技能培养体系,实现毕业生的顺利就业.%Although the combination of work and study can increase the students' practical skills, aspect of jobs is limited. In order to improve employment skills of vocational graduates, the multi -skill training system based on the combination of work and study needs building to achieve successful employment of graduates.

  16. A Robust Weighted Combination Forecasting Method Based on Forecast Model Filtering and Adaptive Variable Weight Determination

    Directory of Open Access Journals (Sweden)

    Lianhui Li

    2015-12-01

    Full Text Available Medium-and-long-term load forecasting plays an important role in energy policy implementation and electric department investment decision. Aiming to improve the robustness and accuracy of annual electric load forecasting, a robust weighted combination load forecasting method based on forecast model filtering and adaptive variable weight determination is proposed. Similar years of selection is carried out based on the similarity between the history year and the forecast year. The forecast models are filtered to select the better ones according to their comprehensive validity degrees. To determine the adaptive variable weight of the selected forecast models, the disturbance variable is introduced into Immune Algorithm-Particle Swarm Optimization (IA-PSO and the adaptive adjustable strategy of particle search speed is established. Based on the forecast model weight determined by improved IA-PSO, the weighted combination forecast of annual electric load is obtained. The given case study illustrates the correctness and feasibility of the proposed method.

  17. Apply 3D model on the customized product color combination for the interior decoration

    Science.gov (United States)

    Chen, Cheih-Ying

    2013-03-01

    The customized product color interface for the interior decoration is designed to simulate the display of various color combination sofas in the interior of the room. There are 144 color combinations of the spatial image resulted from four the interior rooms and 36 popular color sofas. The image compositing technique is adopted to appear the 144 color combinations of the spatial image on computer screen. This study tests the experience of using the interface by the questionnaire for User Interface Satisfaction (QUIS). The results show that the high grade of evaluation items including wonderful, easy, satisfying, stimulating and flexible for the experience of users. Therefore, the entrepreneur who wants to display the color primarily commodity could using the customized color combination interface with 3D models for consumers to take opportunity to find the appropriate products to meet with the interior room, so as to shorten communication time between entrepreneurs and consumers.

  18. THE COMBINED PROCESSES STUDY FOR MANUFACTURING AIRCRAFT PARTS

    Directory of Open Access Journals (Sweden)

    Mr. Boris N. Maryin

    2016-06-01

    Full Text Available The article is devoted to research of the combined processes of forming tubular billets with various media in the process of bending-expanding, breaking-down -expanding while using thermal effects. The paper discusses the processes of forming tubular billets of hard punches, using elastic-granular materials, the peculiarities of forming tubular billets, while the breaking-down -expanding of crimp in a hard punch using elastic-granular bodies. The article presents experimental studies of the bending-expanding of tubular billets in horn-shaped blanks. The authors established the main features of billet distorting in the combined process. The article shows a diagram of the true distorting distribution in the process of stretching and compression in the horn-shaped blanks. The recommendations allow increasing the bending moment and realizing better shaping. The authors make conclusions about the prospects of the application of combined processes in air and rocket.

  19. Fructose and glucose combined with free fatty acids induce metabolic disorders in HepG2 cell: A new model to study the impacts of high-fructose/sucrose and high-fat diets in vitro.

    Science.gov (United States)

    Zhao, Liang; Guo, Xiaoxuan; Wang, Ou; Zhang, Hongjuan; Wang, Yong; Zhou, Feng; Liu, Jia; Ji, Baoping

    2016-04-01

    This work investigated the underlying mechanism of high-fructose/sucrose and high-fat diets, which rapidly induce metabolic syndrome in vivo, via a new cell model. Glucose and/or fructose were used to induce the human hepatoma cell (HepG2) in the presence of palmitic acid, oleic acid, or combined fatty acids (CFA) for 24 h. The alterations in lipid and uric acid production, glucose metabolism, oxidative status, and related genes and proteins were monitored. The cell model that featured metabolic disorders was established by treatment of 10 mM glucose and 15 mM fructose plus 1 mM CFA. Results showed that palmitic acid mainly induced insulin resistance, oxidative stress, and triglyceride (TG) secretion, whereas oleic acid mainly contributed to intracellular TG. Fructose was mainly responsible for uric acid and cholesterol production. In addition, fructose synergistically elevated the intra- and extracellular TG and extracellular malonaldehyde with glucose and CFA. Regulations of genes and proteins associated with carbohydrate metabolism and lipogenesis partially explained the action of fructose in inducing the metabolic disorders in cell. The combination of glucose, fructose, and CFA could successfully induce metabolic disorders in HepG2 cells, including dyslipidemia, insulin resistance, hyperuricemia, and oxidative stress. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Combining University Studies With Work: Influence On Academic Achievement

    OpenAIRE

    Diana M. Yanbarisova

    2014-01-01

    This paper analyses the influence of different combinations of work and study on academic achievement among university students of Yaroslavl region in Russia. The data was collected during the first wave of longitudinal research on the educational and occupational trajectories of graduates of schools and universities conducted by the Institute of Education, Higher School of Economics, Moscow in 2009. The sample consists of 1474 4th and 5th year university students. Five work-study types are d...

  1. Spectral Combination of Global and Regional Ionospheric Models Using Slepian Theory

    Science.gov (United States)

    Etemadfard, Hossein; Mashhadi Hossainali, Masoud

    2016-04-01

    This study suggests a new method for combining function-based regional and global ionospheric models, based on spherical Slepian theory. As the first step of this method, the Global Ionosphere Models (GIMs) of the International GNSS Service (IGS) are transformed to the Spherical Slepian Functions (SSFs), which are named modified GIMs. Then, the observations of the regional GPS networks are expanded in the same SSFs. The maximum degree of the regional model is 15, which is equal to the maximum degree of the GIMs. In the end, the modified GIM and the developed regional model are combined in the spectral domain. The new method is applied to the Arctic region. In the regional modeling, six GPS stations from the Canadian High Arctic Ionosphere Network (CHAIN) and four GPS station from the European Reference Frame (EUREF) network are used. The observation files belong to the day 334 in 2015. The models have been validated with three stations from the CHAIN and the EUREF as check stations. The check stations were used in neither the regional model nor the GIM. According to the obtained result, i the RMSE of GIM, modified GIM and the regional model are 3.7, 2.2 and 1.9 TECU (Total Electron Content Unit =1016electron/m2), respectively. However, the RMSE of the combined model is 1.4 TECU, which shows a significant improvement compare to the other models. The proposed method remarkably improves the quality of the ionospheric modeling in the Arctic region. This may lead to a better understanding of the ionospheric phenomena. Keywords: Regional Modeling, GIM, Spherical Slepian Functions

  2. Combined effects of climate models, hydrological model structures and land use scenarios on hydrological impacts of climate change

    DEFF Research Database (Denmark)

    Karlsson, Ida B.; Sonnenborg, Torben O.; Refsgaard, Jens Christian;

    2016-01-01

    Impact studies of the hydrological response of future climate change are important for the water authorities when risk assessment, management and adaptation to a changing climate are carried out. The objective of this study was to model the combined effect of land use and climate changes...... use scenarios. The results revealed that even though the hydrological models all showed similar performance during calibration, the mean discharge response to climate change varied up to 30%, and the variations were even higher for extreme events (1th and 99th percentile). Land use changes appeared...... to cause little change in mean hydrological responses and little variation between hydrological models. Differences in hydrological model responses to land use were, however, significant for extremes due to dissimilarities in hydrological model structure and process equations. The climate model choice...

  3. Multiplicity fluctuation and correlation of identified baryons in quark combination model

    CERN Document Server

    Song, Jun; Wang, Rui-qin; Shao, Feng-lan

    2016-01-01

    The dynamical fluctuation and correlation of multiplicity distributions of identified baryons and antibaryons produced by the hadronization of the bulk quark system are systematically studied in quark combination model. Starting from the most basic dynamics of quark combination which are necessary for multiplicity study, we analyze moments (variance, skewness and kurtosis) of inclusive multiplicity distribution of identified baryons, two-baryon multiplicity correlations, and baryon-antibaryon multiplicity correlations after the hadronization of quark system with given quark number and antiquark number. We obtain a series of interesting findings, e.g., binomial behavior of multiplicity moments, coincide flavor dependent two-baryon correlation and universal baryon-antibaryon correlation, which can be regarded as general features of quark combination. We further take into account correlations and fluctuations of quark numbers before hadronization to study their influence on multiple production of baryons and ant...

  4. Combining multimedia models with integrated urban water system models for micropollutants

    DEFF Research Database (Denmark)

    De Keyser, W.; Gevaert, V.; Verdonck, F.;

    2010-01-01

    Integrated urban water system (IUWS) modeling aims at assessing the quality of the surface water receiving the urban emissions through sewage treatment plants, combined sewer overflows (CSOS) and stormwater drainage systems However, some micropollutants tend to appear in more than one environment...

  5. Modelling Cr(VI) removal by a combined carbon-activated sludge system

    Energy Technology Data Exchange (ETDEWEB)

    Orozco, A. Micaela Ferro [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA), CONICET, Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ), La Plata (Argentina); Contreras, Edgardo M. [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA), CONICET, Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ), La Plata (Argentina)], E-mail: econtrer@quimica.unlp.edu.ar; Zaritzky, Noemi E. [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA), CONICET, Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ), La Plata (Argentina); Fac. de Ingenieria, UNLP. 47 y 1 (B1900AJJ), La Plata (Argentina)

    2008-01-15

    The combined carbon-activated sludge process has been proposed as an alternative to protect the biomass against toxic substances in wastewaters; however, the information about the effect of powdered-activated carbon (PAC) addition in activated sludge reactors for the treatment of wastewaters containing Cr(VI) is limited. The objectives of the present study were: (a) to evaluate the removal of hexavalent chromium by (i) activated sludge microorganisms in aerobic batch reactors, (ii) powdered-activated carbon, and (iii) the combined action of powdered-activated carbon and biomass; (b) to propose mathematical models that interpret the experimental results. Different Cr(VI) removal systems were tested: (S1) biomass (activated sludge), (S2) PAC, and (S3) the combined activated carbon-biomass system. A Monod-based mathematical model was used to describe the kinetics of Cr(VI) removal in the system S1. A first-order kinetics with respect to Cr(VI) and PAC respectively, was proposed to model the removal of Cr(VI) in the system S2. Cr(VI) removal in the combined carbon-biomass system (S3) was faster than both Cr(VI) removal using PAC or activated sludge individually. Results showed that the removal of Cr(VI) using the activated carbon-biomass system (S3) was adequately described by combining the kinetic equations proposed for the systems S1 and S2.

  6. Comparison and validation of combined GRACE/GOCE models of the Earth's gravity field

    Science.gov (United States)

    Hashemi Farahani, H.; Ditmar, P.

    2012-04-01

    Accurate global models of the Earth's gravity field are needed in various applications: in geodesy - to facilitate the production of a unified global height system; in oceanography - as a source of information about the reference equipotential surface (geoid); in geophysics - to draw conclusions about the structure and composition of the Earth's interiors, etc. A global and (nearly) homogeneous set of gravimetric measurements is being provided by the dedicated satellite mission Gravity Field and Steady-State Ocean Circulation Explorer (GOCE). In particular, Satellite Gravity Gradiometry (SGG) data acquired by this mission are characterized by an unprecedented accuracy/resolution: according to the mission objectives, they must ensure global geoid modeling with an accuracy of 1 - 2 cm at the spatial scale of 100 km (spherical harmonic degree 200). A number of new models of the Earth's gravity field have been compiled on the basis of GOCE data in the course of the last 1 - 2 years. The best of them take into account also the data from the satellite gravimetry mission Gravity Recovery And Climate Experiment (GRACE), which offers an unbeatable accuracy in the range of relatively low degrees. Such combined models contain state-of-the-art information about the Earth's gravity field up to degree 200 - 250. In the present study, we compare and validate such models, including GOCO02, EIGEN-6S, and a model compiled in-house. In addition, the EGM2008 model produced in the pre-GOCE era is considered as a reference. The validation is based on the ability of the models to: (i) predict GRACE K-Band Ranging (KBR) and GOCE SGG data (not used in the production of the models under consideration), and (ii) synthesize a mean dynamic topography model, which is compared with the CNES-CLS09 model derived from in situ oceanographic data. The results of the analysis demonstrate that the GOCE SGG data lead not only to significant improvements over continental areas with a poor coverage with

  7. Global transcription regulation of RK2 plasmids: a case study in the combined use of dynamical mathematical models and statistical inference for integration of experimental data and hypothesis exploration

    Directory of Open Access Journals (Sweden)

    Thomas Christopher M

    2011-07-01

    have demonstrated that the combination of dynamical mathematical models with Bayesian inference is valuable in integrating diverse experimental data and identifying key determinants and parameters for the IncP-1 central control operon. Moreover, we have shown that Bayesian inference and MCA are complementary methods for identification of sensitive parameters. We propose that this demonstrates generic value in applying this combination of approaches to systems biology dynamical modelling.

  8. Prediction Uncertainty Analyses for the Combined Physically-Based and Data-Driven Models

    Science.gov (United States)

    Demissie, Y. K.; Valocchi, A. J.; Minsker, B. S.; Bailey, B. A.

    2007-12-01

    The unavoidable simplification associated with physically-based mathematical models can result in biased parameter estimates and correlated model calibration errors, which in return affect the accuracy of model predictions and the corresponding uncertainty analyses. In this work, a physically-based groundwater model (MODFLOW) together with error-correcting artificial neural networks (ANN) are used in a complementary fashion to obtain an improved prediction (i.e. prediction with reduced bias and error correlation). The associated prediction uncertainty of the coupled MODFLOW-ANN model is then assessed using three alternative methods. The first method estimates the combined model confidence and prediction intervals using first-order least- squares regression approximation theory. The second method uses Monte Carlo and bootstrap techniques for MODFLOW and ANN, respectively, to construct the combined model confidence and prediction intervals. The third method relies on a Bayesian approach that uses analytical or Monte Carlo methods to derive the intervals. The performance of these approaches is compared with Generalized Likelihood Uncertainty Estimation (GLUE) and Calibration-Constrained Monte Carlo (CCMC) intervals of the MODFLOW predictions alone. The results are demonstrated for a hypothetical case study developed based on a phytoremediation site at the Argonne National Laboratory. This case study comprises structural, parameter, and measurement uncertainties. The preliminary results indicate that the proposed three approaches yield comparable confidence and prediction intervals, thus making the computationally efficient first-order least-squares regression approach attractive for estimating the coupled model uncertainty. These results will be compared with GLUE and CCMC results.

  9. Combining partially ranked data in plant breeding and biology: II. Analysis with Rasch model

    Directory of Open Access Journals (Sweden)

    Ivan Simko

    2010-07-01

    Full Text Available Many years of breeding experiments, germplasm screening, and molecular biologic experimentation have generated volumes of sequence, genotype, and phenotype information that have been stored in public data repositories. These resources afford genetic and genomic researchers the opportunity to handle and analyze raw data from multiple laboratories and study groups whose research interests revolve around a common or closely related trait. However, although such data sets are widely available for secondary analysis, their heterogeneous nature often precludes their direct combination and joint exploration. Integration of phenotype information across multiple studies and databases is challenging due to variations in the measurement instruments, endpoint classifications, and biological material employed by each investigator. In the present work, we demonstrate how Rasch measurement model can surmount these problems. The model allows incorporating data sets with partially overlapping variables, large numbers of missing data points and dissimilar ratings of phenotypic endpoints. The model also enables quantifying the extent of heterogeneity between data sets. Biologists can use the model in a data-mining process to obtain combined ratings from various databases and other sources. Subsequently, these ratings can be used for selecting desirable material or (in combination with genotypic information for mapping genes involved in the particular trait. The model is not limited to genetics and breeding and can be applied in many other areas of biology and agriculture.

  10. Combined heat transfer and kinetic models to predict cooking loss during heat treatment of beef meat.

    Science.gov (United States)

    Kondjoyan, Alain; Oillic, Samuel; Portanguen, Stéphane; Gros, Jean-Bernard

    2013-10-01

    A heat transfer model was used to simulate the temperature in 3 dimensions inside the meat. This model was combined with a first-order kinetic models to predict cooking losses. Identification of the parameters of the kinetic models and first validations were performed in a water bath. Afterwards, the performance of the combined model was determined in a fan-assisted oven under different air/steam conditions. Accurate knowledge of the heat transfer coefficient values and consideration of the retraction of the meat pieces are needed for the prediction of meat temperature. This is important since the temperature at the center of the product is often used to determine the cooking time. The combined model was also able to predict cooking losses from meat pieces of different sizes and subjected to different air/steam conditions. It was found that under the studied conditions, most of the water loss comes from the juice expelled by protein denaturation and contraction and not from evaporation.

  11. Combined soft and skeletal tissue modelling of normal and dysmorphic midface postnatal development.

    Science.gov (United States)

    Ibrahim, Amel; Suttie, Michael; Bulstrode, Neil W; Britto, Jonathan A; Dunaway, David; Hammond, Peter; Ferretti, Patrizia

    2016-11-01

    Midface hypoplasia as exemplified by Treacher Collins Syndrome (TCS) can impair appearance and function. Reconstruction involves multiple invasive surgeries with variable long-term outcomes. This study aims to describe normal and dysmorphic midface postnatal development through combined modelling of skeletal and soft tissues and to develop a surgical evaluation tool. Midface skeletal and soft tissue surfaces were extracted from computed tomography scans of 52 control and 14 TCS children, then analysed using dense surface modelling. The model was used to describe midface growth, morphology, and asymmetry, then evaluate postoperative outcomes. Parameters responsible for the greatest variation in midface size and shape showed differences between TCS and controls with close alignment between skeletal and soft tissue models. TCS children exhibited midface dysmorphology and hypoplasia when compared with controls. Asymmetry was also significantly higher in TCS midfaces. Combined modelling was used to evaluate the impact of surgery in one TCS individual who showed normalisation immediately after surgery but reversion towards TCS dysmorphology after 1 year. This is the first quantitative analysis of postnatal midface development using combined modelling of skeletal and soft tissues. We also provide an approach for evaluation of surgical outcomes, laying the foundations for future development of a preoperative planning tool. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  12. Revisiting Dosing Regimen Using Pharmacokinetic/Pharmacodynamic Mathematical Modeling: Densification and Intensification of Combination Cancer Therapy.

    Science.gov (United States)

    Meille, Christophe; Barbolosi, Dominique; Ciccolini, Joseph; Freyer, Gilles; Iliadis, Athanassios

    2016-08-01

    Controlling effects of drugs administered in combination is particularly challenging with a densified regimen because of life-threatening hematological toxicities. We have developed a mathematical model to optimize drug dosing regimens and to redesign the dose intensification-dose escalation process, using densified cycles of combined anticancer drugs. A generic mathematical model was developed to describe the main components of the real process, including pharmacokinetics, safety and efficacy pharmacodynamics, and non-hematological toxicity risk. This model allowed for computing the distribution of the total drug amount of each drug in combination, for each escalation dose level, in order to minimize the average tumor mass for each cycle. This was achieved while complying with absolute neutrophil count clinical constraints and without exceeding a fixed risk of non-hematological dose-limiting toxicity. The innovative part of this work was the development of densifying and intensifying designs in a unified procedure. This model enabled us to determine the appropriate regimen in a pilot phase I/II study in metastatic breast patients for a 2-week-cycle treatment of docetaxel plus epirubicin doublet, and to propose a new dose-ranging process. In addition to the present application, this method can be further used to achieve optimization of any combination therapy, thus improving the efficacy versus toxicity balance of such a regimen.

  13. Combining multi-objective optimization and bayesian model averaging to calibrate forecast ensembles of soil hydraulic models

    Energy Technology Data Exchange (ETDEWEB)

    Vrugt, Jasper A [Los Alamos National Laboratory; Wohling, Thomas [NON LANL

    2008-01-01

    Most studies in vadose zone hydrology use a single conceptual model for predictive inference and analysis. Focusing on the outcome of a single model is prone to statistical bias and underestimation of uncertainty. In this study, we combine multi-objective optimization and Bayesian Model Averaging (BMA) to generate forecast ensembles of soil hydraulic models. To illustrate our method, we use observed tensiometric pressure head data at three different depths in a layered vadose zone of volcanic origin in New Zealand. A set of seven different soil hydraulic models is calibrated using a multi-objective formulation with three different objective functions that each measure the mismatch between observed and predicted soil water pressure head at one specific depth. The Pareto solution space corresponding to these three objectives is estimated with AMALGAM, and used to generate four different model ensembles. These ensembles are post-processed with BMA and used for predictive analysis and uncertainty estimation. Our most important conclusions for the vadose zone under consideration are: (1) the mean BMA forecast exhibits similar predictive capabilities as the best individual performing soil hydraulic model, (2) the size of the BMA uncertainty ranges increase with increasing depth and dryness in the soil profile, (3) the best performing ensemble corresponds to the compromise (or balanced) solution of the three-objective Pareto surface, and (4) the combined multi-objective optimization and BMA framework proposed in this paper is very useful to generate forecast ensembles of soil hydraulic models.

  14. Efficacy of PTX3 and posaconazole combination in a rat model of invasive pulmonary aspergillosis.

    Science.gov (United States)

    Marra, Emanuele; Sousa, Vitor L; Gaziano, Roberta; Pacello, M Lucrezia; Arseni, Brunilde; Aurisicchio, Luigi; De Santis, Rita; Salvatori, Giovanni

    2014-10-01

    Posaconazole is currently used for the prophylaxis of invasive pulmonary aspergillosis (IPA). Limitations to posaconazole usage are drug-drug interactions and side effects. PTX3 is an innate immunity glycoprotein with opsonic activity, proven to be protective in IPA animal models. This study investigated the combination of posaconazole with PTX3. The results indicate synergy between PTX3 and posaconazole against aspergillosis, suggesting that a combination of reduced doses of posaconazole with the immune response enhancer PTX3 might represent a treatment option with a higher therapeutic index than posaconazole.

  15. Combined Mechanistic and Transport Modelling of Metal Humate Complexes

    DEFF Research Database (Denmark)

    Bryan, N. D.; Jones, D.; Griffin, D.

    1999-01-01

    RMC-Environmental Contribution to Task 4, (Model Development and Testing). Reporting period 1998.......RMC-Environmental Contribution to Task 4, (Model Development and Testing). Reporting period 1998....

  16. Combining engineering and data-driven approaches: Development of a generic fire risk model facilitating calibration

    DEFF Research Database (Denmark)

    De Sanctis, G.; Fischer, K.; Kohler, J.

    2014-01-01

    Fire risk models support decision making for engineering problems under the consistent consideration of the associated uncertainties. Empirical approaches can be used for cost-benefit studies when enough data about the decision problem are available. But often the empirical approaches...... a generic risk model that is calibrated to observed fire loss data. Generic risk models assess the risk of buildings based on specific risk indicators and support risk assessment at a portfolio level. After an introduction to the principles of generic risk assessment, the focus of the present paper...... are not detailed enough. Engineering risk models, on the other hand, may be detailed but typically involve assumptions that may result in a biased risk assessment and make a cost-benefit study problematic. In two related papers it is shown how engineering and data-driven modeling can be combined by developing...

  17. A study of combined evaluation of suppliers based on correlation

    Directory of Open Access Journals (Sweden)

    Heting Qiu

    2013-03-01

    Full Text Available Purpose: The Selection of logistics service providers is an important issue in supply chain management. But different evaluation methods may lead to different results, which could cause inconsistent conclusions. This paper makes use of a new perspective to combine with a variety of methods to eliminate the deviation of different single evaluation methods. Design/methodology/approach: This paper expounds the application of the combined evaluation method based on correlation. Entropy method, factor analysis, grey colligation evaluation and AHP have been used for research. Findings: According to the evaluate result, the ranking of suppliers obtained by each method have obvious differences. The result shows that combined evaluation method can eliminate the deviation of different single evaluation methods. Originality/value: The combined evaluation method makes up for the defects of single evaluation methods and obtains a result that is more stable and creditable with smaller deviation. This study can provide the enterprise leaders with more scientific method to select their cooperative companies. 

  18. When one model is not enough: Combining epistemic tools in systems biology

    DEFF Research Database (Denmark)

    Green, Sara

    2013-01-01

    for developing intelligible scientific theories (Leonelli, 2007; Levins, 2006). However, more knowledge is needed on how a combination of different epistemic means can generate and stabilize new entities in science. This paper will draw on Rheinberger’s practice-oriented account of knowledge production....... The conceptual repertoire of Rheinberger’s historical epistemology offers important insights for an analysis of the modelling practice. I illustrate this with a case study on network modeling in systems biology where engineering approaches are applied to the study of biological systems. I shall argue...

  19. SOFOMORE: Combined EEG source and forward model reconstruction

    DEFF Research Database (Denmark)

    Stahlhut, Carsten; Mørup, Morten; Winther, Ole;

    2009-01-01

    We propose a new EEG source localization method that simultaneously performs source and forward model reconstruction (SOFOMORE) in a hierarchical Bayesian framework. Reconstruction of the forward model is motivated by the many uncertainties involved in the forward model, including the representat......We propose a new EEG source localization method that simultaneously performs source and forward model reconstruction (SOFOMORE) in a hierarchical Bayesian framework. Reconstruction of the forward model is motivated by the many uncertainties involved in the forward model, including...... the representation of the cortical surface, conductivity distribution, and electrode positions. We demonstrate in both simulated and real EEG data that reconstruction of the forward model improves localization of the underlying sources....

  20. Development of a Pressure-Dependent Constitutive Model with Combined Multilinear Kinematic and Isotropic Hardening

    Science.gov (United States)

    Allen Phillip A.; Wilson, Christopher D.

    2003-01-01

    The development of a pressure-dependent constitutive model with combined multilinear kinematic and isotropic hardening is presented. The constitutive model is developed using the ABAQUS user material subroutine (UMAT). First the pressure-dependent plasticity model is derived. Following this, the combined bilinear and combined multilinear hardening equations are developed for von Mises plasticity theory. The hardening rule equations are then modified to include pressure dependency. The method for implementing the new constitutive model into ABAQUS is given.

  1. Combining magnetic and seismic studies to constrain processes in massive stars

    CERN Document Server

    Neiner, C; Coste, B; Briquet, M; Mathis, S

    2013-01-01

    The presence of pulsations influences the local parameters at the surface of massive stars and thus it modifies the Zeeman magnetic signatures. Therefore it makes the characterisation of a magnetic field in pulsating stars more difficult and the characterisation of pulsations is thus required for the study of magnetic massive stars. Conversely, the presence of a magnetic field can inhibit differential rotation and mixing in massive stars and thus provides important constraints for seismic modelling based on pulsation studies. As a consequence, it is necessary to combine spectropolarimetric and seismic studies for all massive classical pulsators. Below we show examples of such combined studies and the interplay between physical processes.

  2. Study of the combined effect of electro-activated solutions and heat treatment on the destruction of spores of Clostridium sporogenes and Geobacillus stearothermophilus in model solution and vegetable puree.

    Science.gov (United States)

    Liato, Viacheslav; Labrie, Steve; Viel, Catherine; Benali, Marzouk; Aïder, Mohammed

    2015-10-01

    The combined effect of heat treatment and electro-activated solution (EAS) on the heat resistance of spores of Clostridium sporogenes and Geobacillus stearothermophilus was assessed under various heating and exposure time combinations. The acid and neutral EAS showed the highest inhibitory activity, indicating that these solutions may be considered as strong sporicidal disinfectants. These EAS were able to cause a reduction of ≥6 log of spores of C. sporogenes at 60 °C in only 1 min of exposition. For G. stearothermophilus spores, a reduction of 4.5 log was observed at 60 °C in 1 min, while in 5 min, ≥7 log CFU/ml reduction was observed. Inoculated puree of pea and corn were used as a food matrix for the determination of the heat resistance of these spores during the treatments in glass capillaries. The inactivation kinetics of the spores was studied in an oil bath. Combined treatment by EAS and temperature demonstrated a significant decrease in the heat resistance of C. sporogenes. The D100°C in pea puree with NaCl solution was 66.86 min while with acid and neutral EAS it was reduced down to 3.97 and 2.19 min, respectively. The spore of G. stearothermophilus displayed higher heat resistance as confirmed by other similar studies. Its D130°C in pea puree showed a decrease from 1.45 min in NaCl solution down to 1.30 and 0.93 min for acid and neutral EAS, respectively. The differences between the spores of these species are attributable to their different sensitivities with respect to pH, Redox potential and oxygen.

  3. Combination radiotherapy in an orthotopic mouse brain tumor model.

    Science.gov (United States)

    Kramp, Tamalee R; Camphausen, Kevin

    2012-03-06

    Glioblastoma multiforme (GBM) are the most common and aggressive adult primary brain tumors. In recent years there has been substantial progress in the understanding of the mechanics of tumor invasion, and direct intracerebral inoculation of tumor provides the opportunity of observing the invasive process in a physiologically appropriate environment. As far as human brain tumors are concerned, the orthotopic models currently available are established either by stereotaxic injection of cell suspensions or implantation of a solid piece of tumor through a complicated craniotomy procedure. In our technique we harvest cells from tissue culture to create a cell suspension used to implant directly into the brain. The duration of the surgery is approximately 30 minutes, and as the mouse needs to be in a constant surgical plane, an injectable anesthetic is used. The mouse is placed in a stereotaxic jig made by Stoetling (figure 1). After the surgical area is cleaned and prepared, an incision is made; and the bregma is located to determine the location of the craniotomy. The location of the craniotomy is 2 mm to the right and 1 mm rostral to the bregma. The depth is 3 mm from the surface of the skull, and cells are injected at a rate of 2 μl every 2 minutes. The skin is sutured with 5-0 PDS, and the mouse is allowed to wake up on a heating pad. From our experience, depending on the cell line, treatment can take place from 7-10 days after surgery. Drug delivery is dependent on the drug composition. For radiation treatment the mice are anesthetized, and put into a custom made jig. Lead covers the mouse's body and exposes only the brain of the mouse. The study of tumorigenesis and the evaluation of new therapies for GBM require accurate and reproducible brain tumor animal models. Thus we use this orthotopic brain model to study the interaction of the microenvironment of the brain and the tumor, to test the effectiveness of different therapeutic agents with and without

  4. Learning and working: types of combining university studies with employment

    OpenAIRE

    Yanbarisova, Diana

    2013-01-01

    The purpose of this paper is to mark out and describe different types of combining university studies with work among 4th year university students of Yaroslavl and Tatarstan and to analyze their influence on academic achievement. Seven ‘study-work’ types are defined on the basis of two variables: work schedule and work relatedness to specialty. 1) Full-time work from the 1st-2nd university year not in a specialty field (223 students), 2) Full-time work during senior university years not in a ...

  5. Experimental study of blast mitigating devices based on combined construction

    Science.gov (United States)

    Takayama, K.; Silnikov, M. V.; Chernyshov, M. V.

    2016-09-01

    A robust blast inhibiting bin is the most often used device for damage blast effects suppression. In particular, a top open cylindrical bin significantly reduces a fragmentation effect resulted from a detonation of an explosive device placed inside the bin. However, reduction of blast wave overpressure and impulse by such cylindrical bins is not sufficient [1]. A reasonable alternative to endless increase of height and thickness of robust blast inhibiting bins is a development of destructible inhibitors having no solid elements in their structure and, therefore, excluding secondary fragmentation. So, the family of "Fountain" inhibitors [2,3] localizes and suppresses damaging blast effects due to multiphase working system. The present study is analyzing data obtained in testing of prototypes of new combined inhibitors. Their structure combines robust elements (bottoms, side surfaces) with elements responsible for blast loads reduction due to multi-phase working system (top and low transverse embeddings) and fairings impeding wave propagation in undesirable directions.

  6. Config: A Case Study in Combining Software Engineering Techniques

    Directory of Open Access Journals (Sweden)

    David Maley

    2000-01-01

    Full Text Available Config is a software component of the Graphical R-Matrix Atomic Collision Environment. Its development is documented as a case study combining several software engineering techniques: formal specification, generic programming, object-oriented programming, and design by contract. It is specified in VDM++; and implemented in C++, a language which is becoming more than a curiosity amongst the scientific programming community. C++supports object orientation, a powerful architectural paradigm in designing the structure of software systems, and genericity, an orthogonal dimension to the inheritance hierarchies facilitated by object oriented languages. Support in C++ for design by contract can be added in library form. The combination of techniques make a substantial contribution to the overall software quality.

  7. Combination of Alternative Models by Mutual Data Assimilation: Supermodeling With A Suite of Primitive Equation Models

    Science.gov (United States)

    Duane, G. S.; Selten, F.

    2016-12-01

    Different models of climate and weather commonly give projections/predictions that differ widely in their details. While averaging of model outputs almost always improves results, nonlinearity implies that further improvement can be obtained from model interaction in run time, as has already been demonstrated with toy systems of ODEs and idealized quasigeostrophic models. In the supermodeling scheme, models effectively assimilate data from one another and partially synchronize with one another. Spread among models is manifest as a spread in possible inter-model connection coefficients, so that the models effectively "agree to disagree". Here, we construct a supermodel formed from variants of the SPEEDO model, a primitive-equation atmospheric model (SPEEDY) coupled to ocean and land. A suite of atmospheric models, coupled to the same ocean and land, is chosen to represent typical differences among climate models by varying model parameters. Connections are introduced between all pairs of corresponding independent variables at synoptic-scale intervals. Strengths of the inter-atmospheric connections can be considered to represent inverse inter-model observation error. Connection strengths are adapted based on an established procedure that extends the dynamical equations of a pair of synchronizing systems to synchronize parameters as well. The procedure is applied to synchronize the suite of SPEEDO models with another SPEEDO model regarded as "truth", adapting the inter-model connections along the way. The supermodel with trained connections gives marginally lower error in all fields than any weighted combination of the separate model outputs when used in "weather-prediction mode", i.e. with constant nudging to truth. Stronger results are obtained if a supermodel is used to predict the formation of coherent structures or the frequency of such. Partially synchronized SPEEDO models give a better representation of the blocked-zonal index cycle than does a weighted average

  8. Development of A Novel Murine Model of Combined Radiation and Peripheral Tissue Trauma Injuries.

    Science.gov (United States)

    Antonic, Vlado; Jackson, Isabel L; Ganga, Gurung; Shea-Donohue, Terez; Vujaskovic, Zeljko

    2017-02-01

    Detonation of a 10-kiloton nuclear bomb in an urban setting would result in >1 million casualties, the majority of which would present with combined injuries. Combined injuries, such as peripheral tissue trauma and radiation exposure, trigger inflammatory events that lead to multiple organ dysfunction (MOD) and death, with gastrointestinal (GI) and pulmonary involvement playing crucial roles. The objective of this study was to develop an animal model of combined injuries, peripheral tissue trauma (TBX animal model) combined with total body irradiation with 5% bone marrow shielding (TBI/BM5) to investigate if peripheral tissue trauma contributes to reduced survival. Male C57BL/6J mice were exposed to TBX10%, irradiation (TBI/BM5), or combined injuries (TBX10% + TBI/BM5). Experiments were conducted to evaluate mortality at day 7 after TBI/BM5. Serial euthanasia was performed at day 1, 3 and 6 or 7 after TBI/BM5 to evaluate the time course of pathophysiologic processes in combined injuries. Functional tests were performed to assess pulmonary function and GI motility. Postmortem samples of lungs and jejunum were collected to assess tissue damage. Results indicated higher lethality and shorter survival in the TBX10% +T BI/BM5 group than in the TBX10% or TBI/BM5 groups (day 1 vs. day 7 and 6, respectively). TBI/BM5 alone had no effects on the lungs but significantly impaired GI function at day 6. As expected, in the animals that received severe trauma (TBX10%), we observed impairment in lung function and delay in GI transit in the first 3 days, effects that decreased at later time points. Trauma combined with radiation (TBX10% + TBI/BM5) significantly augmented impairment of the lung and GI function in comparison to TBX10% and TBI/BM5 groups at 24 h. Histologic evaluation indicated that combined injuries caused greater tissue damage in the intestines in TBX10% + TBI/BM5 group when compared to other groups. We describe here the first combined tissue trauma

  9. An empirical movement model for sixgill sharks in Puget Sound: Combining observed and unobserved behavior

    OpenAIRE

    Phillip S. LEVIN, Peter HORNE, Kelly S. ANDREWS, Greg WILLIAMS

    2012-01-01

    Understanding the movement of animals is fundamental to population and community ecology. Historically, it has been difficult to quantify movement patterns of most fishes, but technological advances in acoustic telemetry have increased our abilities to monitor their movement. In this study, we combined small-scale active acoustic tracking with large-scale passive acoustic monitoring to develop an empirical movement model for sixgill sharks in Puget Sound, WA, USA. We began by testing whether ...

  10. Severe combined immunodeficiency mouse and human psoriatic skin chimeras. Validation of a new animal model.

    OpenAIRE

    1995-01-01

    Research into the cause and pathophysiological mechanisms underlying expression of psoriatric skin lesions has been hampered by lack of an appropriate animal model for this common and enigmatic cutaneous disease. These studies characterize normal skin, pre-psoriatic skin, and psoriatic plaque skin samples transplanted onto severe combined immunodeficiency mice. In this report we document that 1), normal, prepsoriatic, and psoriatic plaque keratome skin samples can be transplanted onto severe ...

  11. Design developing conceptual models blade with geometric combined surface

    OpenAIRE

    Juraev, T. H.; Bukhara Technological Institute of Engineering, Bukhara

    2013-01-01

    A conceptual model of the blade using the methods of geometricmodeling principles of industrial design and CAD technologies. Variants are functional use of the proposed model for various working bodies.

  12. GROUT HOPPER MODELING STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.

    2011-08-30

    The Saltstone facility has a grout hopper tank to provide agitator stirring of the Saltstone feed materials. The tank has about 300 gallon capacity to provide a larger working volume for the grout slurry to be held in case of a process upset, and it is equipped with a mechanical agitator, which is intended to keep the grout in motion and agitated so that it won't start to set up. The dry feeds and the salt solution are already mixed in the mixer prior to being transferred to the hopper tank. The hopper modeling study through this work will focus on fluid stirring and agitation, instead of traditional mixing in the literature, in order to keep the tank contents in motion during their residence time so that they will not be upset or solidified prior to transferring the grout to the Saltstone disposal facility. The primary objective of the work is to evaluate the flow performance for mechanical agitators to prevent vortex pull-through for an adequate stirring of the feed materials and to estimate an agitator speed which provides acceptable flow performance with a 45{sup o} pitched four-blade agitator. In addition, the power consumption required for the agitator operation was estimated. The modeling calculations were performed by taking two steps of the Computational Fluid Dynamics (CFD) modeling approach. As a first step, a simple single-stage agitator model with 45{sup o} pitched propeller blades was developed for the initial scoping analysis of the flow pattern behaviors for a range of different operating conditions. Based on the initial phase-1 results, the phase-2 model with a two-stage agitator was developed for the final performance evaluations. A series of sensitivity calculations for different designs of agitators and operating conditions have been performed to investigate the impact of key parameters on the grout hydraulic performance in a 300-gallon hopper tank. For the analysis, viscous shear was modeled by using the Bingham plastic approximation

  13. GROUT HOPPER MODELING STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.

    2011-08-30

    The Saltstone facility has a grout hopper tank to provide agitator stirring of the Saltstone feed materials. The tank has about 300 gallon capacity to provide a larger working volume for the grout slurry to be held in case of a process upset, and it is equipped with a mechanical agitator, which is intended to keep the grout in motion and agitated so that it won't start to set up. The dry feeds and the salt solution are already mixed in the mixer prior to being transferred to the hopper tank. The hopper modeling study through this work will focus on fluid stirring and agitation, instead of traditional mixing in the literature, in order to keep the tank contents in motion during their residence time so that they will not be upset or solidified prior to transferring the grout to the Saltstone disposal facility. The primary objective of the work is to evaluate the flow performance for mechanical agitators to prevent vortex pull-through for an adequate stirring of the feed materials and to estimate an agitator speed which provides acceptable flow performance with a 45{sup o} pitched four-blade agitator. In addition, the power consumption required for the agitator operation was estimated. The modeling calculations were performed by taking two steps of the Computational Fluid Dynamics (CFD) modeling approach. As a first step, a simple single-stage agitator model with 45{sup o} pitched propeller blades was developed for the initial scoping analysis of the flow pattern behaviors for a range of different operating conditions. Based on the initial phase-1 results, the phase-2 model with a two-stage agitator was developed for the final performance evaluations. A series of sensitivity calculations for different designs of agitators and operating conditions have been performed to investigate the impact of key parameters on the grout hydraulic performance in a 300-gallon hopper tank. For the analysis, viscous shear was modeled by using the Bingham plastic approximation

  14. Assigning and combining probabilities in single-case studies.

    Science.gov (United States)

    Manolov, Rumen; Solanas, Antonio

    2012-12-01

    There is currently a considerable diversity of quantitative measures available for summarizing the results in single-case studies. Given that the interpretation of some of them is difficult due to the lack of established benchmarks, the current article proposes an approach for obtaining further numerical evidence on the importance of the results, complementing the substantive criteria, visual analysis, and primary summary measures. This additional evidence consists of obtaining the statistical significance of the outcome when referred to the corresponding sampling distribution. This sampling distribution is formed by the values of the outcomes (expressed as data nonoverlap, R2, etc.) in case the intervention is ineffective. The approach proposed here is intended to offer the outcome's probability of being as extreme when there is no treatment effect without the need for some assumptions that cannot be checked with guarantees. Following this approach, researchers would compare their outcomes to reference values rather than constructing the sampling distributions themselves. The integration of single-case studies is problematic when different metrics are used across primary studies and not all raw data are available. Via the approach for assigning p values it is possible to combine the results of similar studies regardless of the primary effect size indicator. The alternatives for combining probabilities are discussed in the context of single-case studies, pointing out 2 potentially useful methods-one based on a weighted average and the other on the binomial test.

  15. Computer-aided biokinetic modelling combined with in vitro data

    NARCIS (Netherlands)

    Ommen, B. van; Jongh, J. de; Sandt, J. van de; Blaauboer, B.; Hissink, E.; Bogaards, J.; Bladeren, P. van

    1995-01-01

    Within the framework of in vitro alternatives for in vivo safety assessment, the kinetic behaviour of a compound can be described by biokinetic models. These models, with emphasis on the physiologically based pharmacokinetic models, need a variety of biological, physicochemical and biochemical param

  16. A Novel Controller for Model with Combined LFC and AVR Loops of Single Area Power System

    Science.gov (United States)

    Gupta, Monika; Srivastava, Smriti; Gupta, J. R. P.

    2016-03-01

    In this study, a novel controller is designed to study low frequency oscillations for load frequency control (LFC) and voltage control of a single area power system. For more accuracy in dynamic and steady state responses, mutual effects between LFC and automatic voltage regulation (AVR) loops are investigated in a combined simulink model of LFC and AVR loops. The effectiveness of the proposed controller is first simulated on model with LFC loop alone. The proposed controller is a hybrid of neural network and fast traversal filters. The proposed hybrid controller requires less number of samples for training of weights, thus making the system fast. To study the coupling effects of AVR and LFC loops, dynamic performance of a complete system model for low frequency oscillation studies comprising of mechanical and electrical loops is done with the proposed controller.

  17. Toxicity of copper and cadmium in combinations to Duckweed analyzed by the biotic ligand model.

    Science.gov (United States)

    Hatano, Ayumi; Shoji, Ryo

    2008-06-01

    The biotic ligand model (BLM) of acute toxicity to aquatic organisms is based on the concept that metals binding onto biotic ligand may cause toxic effect on the organism. The BLM can take into incorporation between metal speciation and the protective effects of competing cations account. The demonstrated BLM can provide a good estimation of the amount of single metal effect under various conditions such as pH, coexistence of other non toxic cations. However, toxic metals are often found as mixture in nature. This study estimated combined toxicity of Cu and Cd examined by growth inhibition of Duckweed (Lemna paucicostata) by using single toxicity data as toxic unit (TU) derived by three types of model, BLM and two conventional models, free ion activity model (FIAM), and total metal concentration model. According to our results, single toxicity data derived by the BLM can estimate combined toxicity described as a function of TU. Particularly under the high level of heavy metals stress, BLM clearly predicted toxicity of heavy metals compared with other two models. According to numeric correlation (R(2), root mean square error), the order is BLM (R=0.83, RMSE=13.5)> total metal concentration model (R=0.41, RMSE=24.9)> FIAM (R=0.36, RMSE=26.1).

  18. A Microscale Model for Combined CO2 Diffusion and Photosynthesis in Leaves

    Science.gov (United States)

    Ho, Quang Tri; Verboven, Pieter; Yin, Xinyou; Struik, Paul C.; Nicolaï, Bart M.

    2012-01-01

    Transport of CO2 in leaves was investigated by combining a 2-D, microscale CO2 transport model with photosynthesis kinetics in wheat (Triticum aestivum L.) leaves. The biophysical microscale model for gas exchange featured an accurate geometric representation of the actual 2-D leaf tissue microstructure and accounted for diffusive mass exchange of CO2. The resulting gas transport equations were coupled to the biochemical Farquhar-von Caemmerer-Berry model for photosynthesis. The combined model was evaluated using gas exchange and chlorophyll fluorescence measurements on wheat leaves. In general a good agreement between model predictions and measurements was obtained, but a discrepancy was observed for the mesophyll conductance at high CO2 levels and low irradiance levels. This may indicate that some physiological processes related to photosynthesis are not incorporated in the model. The model provided detailed insight into the mechanisms of gas exchange and the effects of changes in ambient CO2 concentration or photon flux density on stomatal and mesophyll conductance. It represents an important step forward to study CO2 diffusion coupled to photosynthesis at the leaf tissue level, taking into account the leaf's actual microstructure. PMID:23144870

  19. A Network Inversion Filter combining GNSS and InSAR for tectonic slip modeling

    Science.gov (United States)

    Bekaert, D. P.; Segall, P.; Wright, T. J.; Hooper, A. J.

    2016-12-01

    Time-dependent slip modeling can be a powerful tool to improve our understanding of the interaction of earthquake cycle processes such as interseismic, coseismic, postseismic, and aseismic slip. Interferometric Synthetic Aperture Radar (InSAR) observations allow us to model slip at depth with a higher spatial resolution than when using GNSS alone. Typically the temporal resolution of InSAR has been limited. However, the recent generation of SAR satellites including Sentinel-1, COSMO-SkyMED, and RADARSAT-2 permits the use of InSAR for time-dependent slip modeling, at intervals of a few days when combined. The increasing amount of SAR data makes a simultaneous data inversion of all epochs challenging. Here, we expanded the original Network Inversion Filter (Segall and Matthews, 1997) to include InSAR observations of surface displacements in addition to GNSS. In the NIF framework, geodetic observations are limited to those of a given epoch, where a physical model describes the slip evolution over time. The combination of the Kalman forward filtering and backward smoothing allows all geodetic observations to constrain the complete observation period. Combining GNSS and InSAR allows us to model time-dependent slip at an unprecedented spatial resolution. We validate the approach with a simulation of the 2006 Guerrero slow slip event. In our study, we emphasize the importance of including the InSAR covariance information, and demonstrate that InSAR provides an additional constraint on the spatial extent of the slow slip. References: Segall, P., and M. Matthews (1997), Time dependent inversion of geodetic data, J. Geophys. Res., 102 (B10), 22,391 - 22,409, doi:10.1029/97JB01795. Bekaert, D., P. Segall, T.J. Wright, and A. Hooper (2016), A Network Inversion Filter combining GNSS and InSAR for tectonic slip modeling, JGR, doi:10.1002/2015JB012638 (open access).

  20. Multistrain models predict sequential multidrug treatment strategies to result in less antimicrobial resistance than combination treatment

    DEFF Research Database (Denmark)

    Ahmad, Amais; Zachariasen, Camilla; Christiansen, Lasse Engbo;

    2016-01-01

    Background: Combination treatment is increasingly used to fight infections caused by bacteria resistant to two or more antimicrobials. While multiple studies have evaluated treatment strategies to minimize the emergence of resistant strains for single antimicrobial treatment, fewer studies have...... generated by a mathematical model of the competitive growth of multiple strains of Escherichia coli.Results: Simulation studies showed that sequential use of tetracycline and ampicillin reduced the level of double resistance, when compared to the combination treatment. The effect of the cycling frequency...... frequency did not play a role in suppressing the growth of resistant strains, but the specific order of the two antimicrobials did. Predictions made from the study could be used to redesign multidrug treatment strategies not only for intramuscular treatment in pigs, but also for other dosing routes....

  1. Tri-level programming model for combined urban traffic signal control and traffic flow guidance

    Institute of Scientific and Technical Information of China (English)

    孙智源; 陆化普; 屈闻聪

    2016-01-01

    In order to balance the temporal-spatial distribution of urban traffic flow, a model is established for combined urban traffic signal control and traffic flow guidance. With consideration of the wide use of fixed signal control at intersections, traffic assignment under traffic flow guidance, and dynamic characteristics of urban traffic management, a tri-level programming model is presented. To reflect the impact of intersection delay on traffic assignment, the lower level model is set as a modified user equilibrium model. The middle level model, which contains several definitional constraints for different phase modes, is built for the traffic signal control optimization. To solve the problem of tide lane management, the upper level model is built up based on nonlinear 0-1 integer programming. A heuristic iterative optimization algorithm (HIOA) is set up to solve the tri-level programming model. The lower level model is solved by method of successive averages (MSA), the middle level model is solved by non-dominated sorting genetic algorithm II (NSGA II), and the upper level model is solved by genetic algorithm (GA). A case study is raised to show the efficiency and applicability of the proposed modelling and computing method.

  2. Combining Bayesian Networks and Agent Based Modeling to develop a decision-support model in Vietnam

    Science.gov (United States)

    Nong, Bao Anh; Ertsen, Maurits; Schoups, Gerrit

    2016-04-01

    Complexity and uncertainty in natural resources management have been focus themes in recent years. Within these debates, with the aim to define an approach feasible for water management practice, we are developing an integrated conceptual modeling framework for simulating decision-making processes of citizens, in our case in the Day river area, Vietnam. The model combines Bayesian Networks (BNs) and Agent-Based Modeling (ABM). BNs are able to combine both qualitative data from consultants / experts / stakeholders, and quantitative data from observations on different phenomena or outcomes from other models. Further strengths of BNs are that the relationship between variables in the system is presented in a graphical interface, and that components of uncertainty are explicitly related to their probabilistic dependencies. A disadvantage is that BNs cannot easily identify the feedback of agents in the system once changes appear. Hence, ABM was adopted to represent the reaction among stakeholders under changes. The modeling framework is developed as an attempt to gain better understanding about citizen's behavior and factors influencing their decisions in order to reduce uncertainty in the implementation of water management policy.

  3. Operative and diagnostic hysteroscopy: A novel learning model combining new animal models and virtual reality simulation.

    Science.gov (United States)

    Bassil, Alfred; Rubod, Chrystèle; Borghesi, Yves; Kerbage, Yohan; Schreiber, Elie Servan; Azaïs, Henri; Garabedian, Charles

    2017-04-01

    Hysteroscopy is one of the most common gynaecological procedure. Training for diagnostic and operative hysteroscopy can be achieved through numerous previously described models like animal models or virtual reality simulation. We present our novel combined model associating virtual reality and bovine uteruses and bladders. End year residents in obstetrics and gynaecology attended a full day workshop. The workshop was divided in theoretical courses from senior surgeons and hands-on training in operative hysteroscopy and virtual reality Essure(®) procedures using the EssureSim™ and Pelvicsim™ simulators with multiple scenarios. Theoretical and operative knowledge was evaluated before and after the workshop and General Points Averages (GPAs) were calculated and compared using a Student's T test. GPAs were significantly higher after the workshop was completed. The biggest difference was observed in operative knowledge (0,28 GPA before workshop versus 0,55 after workshop, pTeaching operative and diagnostic hysteroscopy is essential. Managing this training through a full day workshop using a combined animal model and virtual reality simulation is an efficient model not described before. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Combined effects of climate models, hydrological model structures and land use scenarios on hydrological impacts of climate change

    Science.gov (United States)

    Karlsson, Ida B.; Sonnenborg, Torben O.; Refsgaard, Jens Christian; Trolle, Dennis; Børgesen, Christen Duus; Olesen, Jørgen E.; Jeppesen, Erik; Jensen, Karsten H.

    2016-04-01

    Impact studies of the hydrological response of future climate change are important for the water authorities when risk assessment, management and adaptation to a changing climate are carried out. The objective of this study was to model the combined effect of land use and climate changes on hydrology for a 486 km2 catchment in Denmark and to evaluate the sensitivity of the results to the choice of hydrological model. Three hydrological models, NAM, SWAT and MIKE SHE, were constructed and calibrated using similar methods. Each model was forced with results from four climate models and four land use scenarios. The results revealed that even though the hydrological models all showed similar performance during calibration, the mean discharge response to climate change varied up to 30%, and the variations were even higher for extreme events (1th and 99th percentile). Land use changes appeared to cause little change in mean hydrological responses and little variation between hydrological models. Differences in hydrological model responses to land use were, however, significant for extremes due to dissimilarities in hydrological model structure and process equations. The climate model choice remained the dominant factor for mean discharge, low and high flows as well as hydraulic head at the end of the century.

  5. Models of intracellular mechanisms of plant bioelectrical potentials caused by combined stimulation

    Directory of Open Access Journals (Sweden)

    D. V. Chernetchenko

    2014-10-01

    Full Text Available This paper deals with bioelectrical potentials of the plants recorded during different types of stimuli and combined stimulus as well. All registrations were observed on the leaves of the corn. We used different stimuli, such as cold, heat, photo- and electrical stimulation, and certain combination of this stimuli. Hardware and software system for automated recording of bioelectrical potentials has been successfully used in this work. We proposed the universal pattern of bioelectrical potentials’ recording which allowed to detect the response of the biological object to different stimuli and various combinations of these stimuli. This pattern can be used for the deeper understanding of biological mechanisms of electrical potentials’ generation in cells and discovering of processes of accommodation of whole organisms to these stimuli. Integrated system of recording and biometrical processing was used for analysis of corn leaves electrical responses to the thermal stimuli. The dynamics of these potentials was studied, with the quantitative analysis of the potential level stabilization.We calculated the ratio of amplitude of response potentials to the first response amplitude. Mathematical models of the plant cell were used for studying of intracellular mechanisms of biopotentials gereration. As a result of modeling, we revealed that electrical response of the cells was based on selectiveconductivity of cell membrane for Н+ and Ca2+ ions. Therefore, we showed the biophysical relation of plant potentials to underlying intracellular biophysical mechanisms during thermal and combined stimulation.

  6. [Clinical study on viral hepatitis combined with aplastic anemia].

    Science.gov (United States)

    Lu, Yao; Zhang, Yan-li; Shen, Ge; Zhang, Lu; Wang, Lin; Qiu, Guo-hua; Wu, Yun-zhong; Yang, Min; Li, Ming-hui

    2011-08-01

    To study the clinical features, outcomes and treatments of viral hepatitis combined with aplastic anemia. 25 cases diagnosed as viral hepatits combined with aplastic anemia in Beijing Ditan Hsopital between April 2004 and September 2009 were retrospectively analyzed. In this group of patients aplastic anemia was finally diagnosed by bone marrow aspiration. We collected clinical data of these patients, including a history of liver disease, drug allergies, hospital medication history, laboratory data, and then performed descriptive analysis. 25 patients with viral hepatitis were diagnosed as complicated with aplastic anemia by histopathological data. Among these patients, 17 were male and 8 were women. Viral hepatitis included: chronic hepatitis B (12 cases), chronic hepatitis C (4 cases), acute hepatits E (1 case), hepatitis caused by CMV infection (1 case), and unclassified hepatitis (7 cases). Among these patients, 7 were diagnosed as severe hepatits. Considering previous history, only 3 patients had history of short term interferon therapy before hospitalization, and the remaining patients did not use drug that affects blood system. Treatments were as followings: using colony stimulating factor in 6 patients, gamma globulin in 9 patients, glucocorticoids in 3 patients, erythropoietin in 1 patient, only oral drug to raise erythrocytes in 2 patients, red blood cells transfusion in 6 patients, platelets transfusion in 2 patients. As for clinical outcomes, 20 patients acquired improved condition and were dicharged, 3 patients were discharged voluntarily and 2 patients died of severe hepatits combined with other complications. Main treatments of viral hepatitis combined with aplastic anemia were to treat primary hepatopathy and nucleoside analogue-based antiviral therapy, to provide symptomatic and supportive treatment for blood diseases. Blood diseases would recover simultaneously while liver disease was improved, and the prognosis was good.

  7. Planck focal plane instruments: advanced modelization and combined analysis

    Science.gov (United States)

    Zonca, Andrea; Mennella, Aniello

    2012-08-01

    This thesis is the result of my work as research fellow at IASF-MI, Milan section of the Istituto di Astrofisica Spaziale e Fisica Cosmica, part of INAF, Istituto Nazionale di Astrofisica. This work started in January 2006 in the context of the PhD school program in Astrophysics held at the Physics Department of Universita' degli Studi di Milano under the supervision of Aniello Mennella. The main topic of my work is the software modelling of the Low Frequency Instrument (LFI) radiometers. The LFI is one of the two instruments on-board the European Space Agency Planck Mission for high precision measurements of the anisotropies of the Cosmic Microwave Background (CMB). I was also selected to participate at the International Doctorate in Antiparticles Physics, IDAPP. IDAPP is funded by the Italian Ministry of University and Research (MIUR) and coordinated by Giovanni Fiorentini (Universita' di Ferrara) with the objective of supporting the growing collaboration between the Astrophysics and Particles Physics communities. It is an international program in collaboration with the Paris PhD school, involving Paris VI, VII and XI Universities, leading to a double French-Italian doctoral degree title. My work was performed with the co-tutoring of Jean-Michel Lamarre, Instrument Scientist of the High Frequency Instrument (HFI), the bolometric instrument on-board Planck. Thanks to this collaboration I had the opportunity to work with the HFI team for four months at the Paris Observatory, so that the focus of my activity was broadened and included the study of cross-correlation between HFI and LFI data. Planck is the first CMB mission to have on-board the same satellite very different detection technologies, which is a key element for controlling systematic effects and improve measurements quality.

  8. Combining logistic regression and neural networks to create predictive models.

    OpenAIRE

    Spackman, K. A.

    1992-01-01

    Neural networks are being used widely in medicine and other areas to create predictive models from data. The statistical method that most closely parallels neural networks is logistic regression. This paper outlines some ways in which neural networks and logistic regression are similar, shows how a small modification of logistic regression can be used in the training of neural network models, and illustrates the use of this modification for variable selection and predictive model building wit...

  9. Hybrid Modeling and Optimization of Manufacturing Combining Artificial Intelligence and Finite Element Method

    CERN Document Server

    Quiza, Ramón; Davim, J Paulo

    2012-01-01

    Artificial intelligence (AI) techniques and the finite element method (FEM) are both powerful computing tools, which are extensively used for modeling and optimizing manufacturing processes. The combination of these tools has resulted in a new flexible and robust approach as several recent studies have shown. This book aims to review the work already done in this field as well as to expose the new possibilities and foreseen trends. The book is expected to be useful for postgraduate students and researchers, working in the area of modeling and optimization of manufacturing processes.

  10. Combining spanwise morphing, inline motion and model based optimization for force magnitude and direction control

    Science.gov (United States)

    Scheller, Johannes; Braza, Marianna; Triantafyllou, Michael

    2016-11-01

    Bats and other animals rapidly change their wingspan in order to control the aerodynamic forces. A NACA0013 type airfoil with dynamically changing span is proposed as a simple model to experimentally study these biomimetic morphing wings. Combining this large-scale morphing with inline motion allows to control both force magnitude and direction. Force measurements are conducted in order to analyze the impact of the 4 degree of freedom flapping motion on the flow. A blade-element theory augmented unsteady aerodynamic model is then used to derive optimal flapping trajectories.

  11. Combining Coarse-Grained Protein Models with Replica-Exchange All-Atom Molecular Dynamics

    CERN Document Server

    Wabik, Jacek; Gront, Dominik; Kouza, Maksim; Kolinski, Andrzej

    2013-01-01

    We describe a combination of all-atom simulations with CABS, a well-established coarse-grained protein modeling tool, into a single multiscale protocol. The simulation method has been tested on the C-terminal beta hairpin of protein G, a model system of protein folding. After reconstructing atomistic details, conformations derived from the CABS simulation were subjected to replica-exchange molecular dynamics simulations with OPLS-AA and AMBER99sb force fields in explicit solvent. Such a combination accelerates system convergence several times in comparison with all-atom simulations starting from the extended chain conformation, demonstrated by the analysis of melting curves, the number of native-like conformations as a function of time and secondary structure propagation. The results strongly suggest that the proposed multiscale method could be an efficient and accurate tool for high-resolution studies of protein folding dynamics in larger systems.

  12. Combining Coarse-Grained Protein Models with Replica-Exchange All-Atom Molecular Dynamics

    Directory of Open Access Journals (Sweden)

    Andrzej Koliński

    2013-05-01

    Full Text Available We describe a combination of all-atom simulations with CABS, a well-established coarse-grained protein modeling tool, into a single multiscale protocol. The simulation method has been tested on the C-terminal beta hairpin of protein G, a model system of protein folding. After reconstructing atomistic details, conformations derived from the CABS simulation were subjected to replica-exchange molecular dynamics simulations with OPLS-AA and AMBER99sb force fields in explicit solvent. Such a combination accelerates system convergence several times in comparison with all-atom simulations starting from the extended chain conformation, demonstrated by the analysis of melting curves, the number of native-like conformations as a function of time and secondary structure propagation. The results strongly suggest that the proposed multiscale method could be an efficient and accurate tool for high-resolution studies of protein folding dynamics in larger systems.

  13. Combining coarse-grained protein models with replica-exchange all-atom molecular dynamics.

    Science.gov (United States)

    Wabik, Jacek; Kmiecik, Sebastian; Gront, Dominik; Kouza, Maksim; Koliński, Andrzej

    2013-05-10

    We describe a combination of all-atom simulations with CABS, a well-established coarse-grained protein modeling tool, into a single multiscale protocol. The simulation method has been tested on the C-terminal beta hairpin of protein G, a model system of protein folding. After reconstructing atomistic details, conformations derived from the CABS simulation were subjected to replica-exchange molecular dynamics simulations with OPLS-AA and AMBER99sb force fields in explicit solvent. Such a combination accelerates system convergence several times in comparison with all-atom simulations starting from the extended chain conformation, demonstrated by the analysis of melting curves, the number of native-like conformations as a function of time and secondary structure propagation. The results strongly suggest that the proposed multiscale method could be an efficient and accurate tool for high-resolution studies of protein folding dynamics in larger systems.

  14. Combining the Performance Strengths of the Logistic Regression and Neural Network Models: A Medical Outcomes Approach

    Directory of Open Access Journals (Sweden)

    Wun Wong

    2003-01-01

    Full Text Available The assessment of medical outcomes is important in the effort to contain costs, streamline patient management, and codify medical practices. As such, it is necessary to develop predictive models that will make accurate predictions of these outcomes. The neural network methodology has often been shown to perform as well, if not better, than the logistic regression methodology in terms of sample predictive performance. However, the logistic regression method is capable of providing an explanation regarding the relationship(s between variables. This explanation is often crucial to understanding the clinical underpinnings of the disease process. Given the respective strengths of the methodologies in question, the combined use of a statistical (i.e., logistic regression and machine learning (i.e., neural network technology in the classification of medical outcomes is warranted under appropriate conditions. The study discusses these conditions and describes an approach for combining the strengths of the models.

  15. Urban traffic noise assessment by combining measurement and model results

    NARCIS (Netherlands)

    Eerden, F.J.M. van der; Graafland, F.; Wessels, P.W.; Basten, T.G.H.

    2013-01-01

    A model based monitoring system is applied on a local scale in an urban area to obtain a better understanding of the traffic noise situation. The system consists of a scalable sensor network and an engineering model. A better understanding is needed to take appropriate and cost efficient measures,

  16. Reservoir Modeling Combining Geostatistics with Markov Chain Monte Carlo Inversion

    DEFF Research Database (Denmark)

    Zunino, Andrea; Lange, Katrine; Melnikova, Yulia;

    2014-01-01

    , multi-step forward model (rock physics and seismology) and to provide realistic estimates of uncertainties. To generate realistic models which represent samples of the prior distribution, and to overcome the high computational demand, we reduce the search space utilizing an algorithm drawn from...

  17. Multilayer piezoelectric transducer models combined with Field II

    DEFF Research Database (Denmark)

    Bæk, David; Willatzen, Morten; Jensen, Jørgen Arendt

    2012-01-01

    with a polymer ring, and submerged into water. The transducer models are developed to account for any external electrical loading impedance in the driving circuit. The models are adapted to calculate the surface acceleration needed by the Field II software in predicting pressure pulses at any location in front...

  18. A combined BEM/FEM method for IC substrate modeling

    NARCIS (Netherlands)

    Schrik, E.

    2006-01-01

    The research presented in this thesis was done in the context of the modeling of parasitic physical effects, like field couplings and crosstalk, that may adversely affect the functional performance of Integrated Circuits (ICs). The modeling of parasitic effects, through simulations with the resultin

  19. Study of efficacy of the combination of carbamazepine with nootropics on cognitive processes in epilepsy

    Directory of Open Access Journals (Sweden)

    Ivanov A.V.

    2013-03-01

    Full Text Available The authors studied the efficacy of combination of carbamazepine with nootropic drugs on cognitive processes in patients with epilepsy in experiment in order to reduce the side effects of anticonvulsant therapy. Analysis of anticonvulsant effect of the combination of drugs was carried out on 36 white nonlinear rats of both sexes weighing 160-180 g by the method of maximum electroshock, and the analysis of antiamnestic effect - using a model of retrograde amnesia on 80 white adult male rats weighing 160 - 200 g. For studying the mnemotropic activity of drug, the method of the conditioned reflex of active avoidance was used. The authors discovered that the isolated use of carbamazepine has the most negative influence on cognitive processes in animals, namely the formation of skill, memory engrams and consolidating memory trace as compared with the combined use of carbamazepine with neuroprotective drugs. It was found that the use of combinations of carbamazepine and nootropics in the experiment does not prevent the development of seizures completely, however, these combination can significantly reduce the duration of seizures (p <0.0001. Study of the effectiveness of the combined use of carbamazepine with nootropic drugs, revealed, that the tested drug combinations have a positive effect on cognitive processes and show neuroprotective effect on the brain structures of animals. The revealed effects of combined use of carbamazepine with nootropic drugs by the strength and intensity of the impact is much higher than isolated, while using carbamazepine. It was found, that the most effective combination is a combination of carbamazepine with Gliatilin.

  20. Multivariate Modelling of Extreme Load Combinations for Wind Turbines

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov

    2015-01-01

    We demonstrate a model for estimating the joint probability distribution of two load components acting on a wind turbine blade cross section. The model addresses the problem of modelling the probability distribution of load time histories with large periodic components by dividing the signal...... into a periodic part and a perturbation term, where each part has a known probability distribution. The proposed model shows good agreement with simulated data under stationary conditions, and a design load envelope based on this model is comparable to the load envelope estimated using the standard procedure...... for determining contemporaneous loads. By defining a joint probability distribution and full return-period contours for multiple load components, the suggested procedure gives the possibility for determining the most critical loading direction in a blade cross section, or for carrying out reliability analysis...

  1. Coherent beam combination of fiber lasers with a strongly confined waveguide: numerical model.

    Science.gov (United States)

    Tao, Rumao; Si, Lei; Ma, Yanxing; Zhou, Pu; Liu, Zejin

    2012-08-20

    Self-imaging properties of fiber lasers in a strongly confined waveguide (SCW) and their application in coherent beam combination (CBC) are studied theoretically. Analytical formulas are derived for the positions, amplitudes, and phases of the N images at the end of an SCW, which is important for quantitative analysis of waveguide CBC. The formulas are verified with experimental results and numerical simulation of a finite difference beam propagation method (BPM). The error of our analytical formulas is less than 6%, which can be reduced to less than 1.5% with Goos-Hahnchen penetration depth considered. Based on the theoretical model and BPM, we studied the combination of two laser beams based on an SCW. The effects of the waveguide refractive index and Gaussian beam waist are studied. We also simulated the CBC of nine and 16 fiber lasers, and a single beam without side lobes was achieved.

  2. RECONSTRUCTION OF 3D VECTOR MODELS OF BUILDINGS BY COMBINATION OF ALS, TLS AND VLS DATA

    Directory of Open Access Journals (Sweden)

    H. Boulaassal

    2012-09-01

    Full Text Available Airborne Laser Scanning (ALS, Terrestrial Laser Scanning (TLS and Vehicle based Laser Scanning (VLS are widely used as data acquisition methods for 3D building modelling. ALS data is often used to generate, among others, roof models. TLS data has proven its effectiveness in the geometric reconstruction of building façades. Although the operating algorithms used in the processing chain of these two kinds of data are quite similar, their combination should be more investigated. This study explores the possibility of combining ALS and TLS data for simultaneously producing 3D building models from bird point of view and pedestrian point of view. The geometric accuracy of roofs and façades models is different due to the acquisition techniques. In order to take these differences into account, the surfaces composing roofs and façades are extracted with the same algorithm of segmentation. Nevertheless the segmentation algorithm must be adapted to the properties of the different point clouds. It is based on the RANSAC algorithm, but has been applied in a sequential way in order to extract all potential planar clusters from airborne and terrestrial datasets. Surfaces are fitted to planar clusters, allowing edge detection and reconstruction of vector polygons. Models resulting from TLS data are obviously more accurate than those generated from ALS data. Therefore, the geometry of the roofs is corrected and adapted according to the geometry of the corresponding façades. Finally, the effects of the differences between raw ALS and TLS data on the results of the modeling process are analyzed. It is shown that such combination could be used to produce reliable 3D building models.

  3. Study on induction of radioprotection using antioxidant combinations

    Energy Technology Data Exchange (ETDEWEB)

    Lim, J. S.; Choe, Y. K.; Lee, H. G.; Kim, K. D. [Korea Research Institute of Bioscience and Biotechnology, Taejeon (Korea)

    2000-04-01

    Antioxidants are applied in tumor patients during chemo- or radiotherapy due to its cytoprotective effects. Therefore, aim of our study was to evaluate the effect of exposure with a variety of antioxidants on primary bone marrow cells after {gamma}-irradiation. We studied the radiation-induced cell death in comparison to mouse bone marrow cells after single-dose irradiation with 1, 2, 3 or 6 Gy and controls without irradiation. Cells cultured in vitro had been exposed to different concentrations of antioxidants prior to {gamma}-irradiation. The effect was evaluated 6, 8, 17 or 24 h after radiation exposure by propium iodide staining. While sodium selenite and N-acetylcyseine could achieve significant inhibition of radiation-induced cell death, aminoguanidine and alpha-lipoic acid were not shown to inhibit it. Furthermore, the combination of N-acetylcysteine with some mild antioxidants such as BHA, propyl gallate, quercetin or trolox induced the significant inhibition of radiation-induced cell death. However, these effect was different depending on the duration of radiation exposure and the concentration of antioxidants added in culture. Although the radioprotective effect of antioxidants should be compared with the effect on tumor itself, our results indicate that the use of antioxidants in combination can efficiently modulate the radiation-induced cell damage like apoptosis and can be applied in tumor patients during radiotherapy. 26 refs., 7 figs., 7 tabs. (Author)

  4. Combined spectroscopic and quantum chemical studies of ezetimibe

    Science.gov (United States)

    Prajapati, Preeti; Pandey, Jaya; Shimpi, Manishkumar R.; Srivastava, Anubha; Tandon, Poonam; Velaga, Sitaram P.; Sinha, Kirti

    2016-12-01

    Ezetimibe (EZT) is a hypocholesterolemic agent used for the treatment of elevated blood cholesterol levels as it lowers the blood cholesterol by blocking the absorption of cholesterol in intestine. Study aims to combine experimental and computational methods to provide insights into the structural and vibrational spectroscopic properties of EZT which is important for explaining drug substance physical and biological properties. Computational study on molecular properties of ezetimibe is presented using density functional theory (DFT) with B3LYP functional and 6-311++G(d,p) basis set. A detailed vibrational assignment has been done for the observed IR and Raman spectra of EZT. In addition to the conformational study, hydrogen bonding and molecular docking studies have been also performed. For conformational studies, the double well potential energy curves have been plotted for the rotation around the six flexible bonds of the molecule. UV absorption spectrum was examined in methanol solvent and compared with calculated one in solvent environment (IEF-PCM) using TD-DFT/6-31G basis set. HOMO-LUMO energy gap of both the conformers have also been calculated in order to predict its chemical reactivity and stability. The stability of the molecule was also examined by means of natural bond analysis (NBO) analysis. To account for the chemical reactivity and site selectivity of the molecules, molecular electrostatic potential (MEPS) map has been plotted. The combination of experimental and calculated results provide an insight into the structural and vibrational spectroscopic properties of EZT. In order to give an insight for the biological activity of EZT, molecular docking of EZT with protein NPC1L1 has been done.

  5. Combining Spatial Models for Shallow Landslides and Debris-Flows Prediction

    Directory of Open Access Journals (Sweden)

    Eurípedes Vargas do Amaral

    2013-05-01

    Full Text Available Mass movements in Brazil are common phenomena, especially during strong rainfall events that occur frequently in the summer season. These phenomena cause losses of lives and serious damage to roads, bridges, and properties. Moreover, the illegal occupation by slums on the slopes around the cities intensifies the effect of the mass movement. This study aimed to develop a methodology that combines models of shallow landslides and debris-flows in order to create a map with landslides initiation and debris-flows volume and runout distance. The study area comprised of two catchments in Rio de Janeiro city: Quitite and Papagaio that drained side by side the west flank of the Maciço da Tijuca, with an area of 5 km2. The method included the following steps: (a location of the susceptible areas to landslides using SHALSTAB model; (b determination of rheological parameters of debris-flow from the back-analysis technique; and (c combination of SHALSTAB and FLO-2D models to delineate the areas more susceptible to mass movements. These scenarios were compared with the landslide and debris-flow event of February 1996. Many FLO-2D simulations were exhaustively made to estimate the rheological parameters from the back-analysis technique. Those rheological coefficients of single simulation were back-calculated by adjusting with area and depth of the debris-flow obtained from field data. The initial material volume in the FLO-2D simulations was estimated from SHALSTAB model. The combination of these two mathematical models, SHALSTAB and FLO-2D, was able to predict both landslides and debris-flow events. Such procedures can reduce the casualties and property damage, delineating hazard areas, to estimate hazard intensities for input into risk studies providing information for public policy and planning.

  6. Evaluation of drug combination for glioblastoma based on an intestine-liver metabolic model on microchip.

    Science.gov (United States)

    Jie, Mingsha; Mao, Sifeng; Liu, Hanyang; He, Ziyi; Li, Hai-Fang; Lin, Jin-Ming

    2017-08-30

    An intestine-liver-glioblastoma biomimetic system was developed to evaluate the drug combination therapy for glioblastoma. A hollow fiber (HF) was embedded into the upper layer of the microfluidic chip for culturing Caco-2 cells to mimic drug delivery as an artificial intestine. HepG2 cells cultured in the bottom chamber of the chip acted as an artificial liver for metabolizing the drugs. The dual-drug combination to glioblastoma U251 cells was evaluated based on the intestine-liver metabolic model. The drugs, irinotecan (CPT-11), temozolomide (TMZ) and cyclophosphamide (CP), were used to dynamically stimulate the cells by continuous infusion into the intestine unit. After intestine absorption and liver metabolism, the prodrugs were transformed to active metabolites, which induced glioblastoma cells apoptosis. The anticancer activity of the CPT-11 and TMZ combination is significantly enhanced compared to that of the single drug treatments. Combination index (CI) values of the combination groups, CPT-11 and TMZ, CPT-11 and CP, and TMZ and CP, at half maximal inhibitory concentration were 0.137, 0.288, and 0.482, respectively. The results indicated that the CPT-11 and TMZ combination was superior to the CPT-11 and CP group as well as the TMZ and CP group towards the U251 cells. The metabolism mechanism of CPT-11 and TMZ was further studied by coupling with mass spectrometric analysis. The biomimetic model enables the performance of long-term cell co-culture, drug delivery, metabolism and real-time analysis of drug effects, promising systematic in vitro mimicking of physiological and pharmacological processes.

  7. Modeling of Combined Phenomena Affecting an AUV Stealth Vehicle

    Directory of Open Access Journals (Sweden)

    Miroslaw Gerigk

    2016-12-01

    Full Text Available In the paper some results of research connected with modeling the basic stealth characteristics of an AUV vehicle are presented. First of all a general approach to design of the stealth AUV autonomous underwater vehicles under consideration is introduced. Then the AUV stealth vehicle concept is briefly described. Next a method of modeling of the stealth characteristics is briefly described. As an example of the stealth characteristics investigations some results of modeling the boundary layer and wake are presented. Some remarks regarding the behavior of the AUV stealth vehicle in the submerged conditions are given. The final conclusions are presented.

  8. A Retrospective Study of Combined Cardiac and Carotid Surgery

    Directory of Open Access Journals (Sweden)

    Fabrizio Sansone

    2012-08-01

    Full Text Available Introduction: A combined carotid endarterectomy (CEA and cardiac procedure has higher early risk of stroke than isolated CEA because of the widespread atherosclerosis in patients selected for simultaneous procedures. In this retrospective study, we review the results of combined coronary artery bypass grafting (CABG and carotid endarterectomy (CEA procedures. Materials and methods: Between January 2000 and December 2007, 91 patients with a mean age of 69.2+6.6 (24/67 female/male underwent combined operations (CEA-CABG on cardiopulmonary bypass (CPB as elective surgery. The study population was divided, as follows: Group A: 83 patients (91.2% had both venous and arterial revascularization; Group B: 8 patients (8.8% had total arterial revascularization. CEA was performed in case of stenosis more than 80% and always before cardiac operation. These techniques were used: standard procedure (54.8%, eversion (39.2%, patch enlargement (6%. Immediately after the vascular procedure, CABGs were performed through median sternotomy. The mean EUROscore was 6.9+2.5%. Results: All neurological complications were in the group who underwent both venous and arterial revascularization (Group A, where a proximal anastomosis was made. All complications and deaths were in group A. Six patients had stroke (6.6% and 2 had acute myocardial infarction (AMI (2.2%. There were 8 in-hospital deaths (8.8% and 1 late death (for stroke after five months. Conclusions: In our center, the incidence of stroke in simultaneous cardiovascular procedures was 5.5 times greater than in isolated cardiac or vascular procedures, which was probably related to the widespread vessels disease. An aortic cross clamp and surgical procedure on the ascending aorta are relevant risk factors for developing neurological events; much attention should be paid to aortic manipulation. In the sub-group who underwent total arterial revascularization with associated CEA procedures, we had no neurological

  9. A void coalescence model for combined tension and shear

    Science.gov (United States)

    Butcher, C.; Chen, Z. T.

    2009-03-01

    The influence of shear loading on damage development in Gurson-based models has long been neglected resulting in inadequate fracture strain predictions at low triaxiality where shear effects become significant. The plastic limit-load fracture criterion used in advanced Gurson models neglects the influence of shear loading and overestimates the fracture strain and porosity at low triaxiality. In this paper, we extend the recently proposed shear damage model of Xue [1] to provide a stronger physical foundation by removing the simplifying assumptions. Then we directly modify the plastic limit-load fracture criterion by coupling with the extended shear damage model to account for shear weakening and failure of the intervoid ligament in void coalescence. We apply the modified plastic limit-load criterion to predict the necking of sheet tensile specimens and find very good agreement with the available experimental results.

  10. A Combined Statistical-Microstructural Model for Simulation of Sintering

    Energy Technology Data Exchange (ETDEWEB)

    BRAGINSKY,MICHAEL V.; DEHOFF,ROBERT T.; OLEVSKY,EUGENE A.; TIKARE,VEENA

    1999-10-22

    Sintering theory has been developed either as the application of complex diffusion mechanisms to a simple geometry or as the deformation and shrinkage of a continuum body. They present a model that can treat in detail both the evolution of microstructure and the sintering mechanisms, on the mesoscale, so that constitutive equations with detail microstructural information can be generated. The model is capable of simulating vacancy diffusion by grain boundary diffusion, annihilation of vacancies at grain boundaries resulting in densification, and coarsening of the microstructural features. In this paper, they review the stereological theory of sintering and its application to microstructural evolution and the diffusion mechanism, which lead to sintering. They then demonstrate how these stereological concepts and diffusion mechanisms were incorporated into a kinetic Monte Carlo model to simulate sintering. Finally, they discuss the limitations of this model.

  11. On combining Thole's induced point dipole model with fixed charge distributions in molecular mechanics force fields.

    Science.gov (United States)

    Antila, Hanne S; Salonen, Emppu

    2015-04-15

    The Thole induced point dipole model is combined with three different point charge fitting methods, Merz-Kollman (MK), charges from electrostatic potentials using a grid (CHELPG), and restrained electrostatic potential (RESP), and two multipole algorithms, distributed multipole analysis (DMA) and Gaussian multipole model (GMM), which can be used to describe the electrostatic potential (ESP) around molecules in molecular mechanics force fields. This is done to study how the different methods perform when intramolecular polarizability contributions are self-consistently removed from the fitting done in the force field parametrization. It is demonstrated that the polarizable versions of the partial charge models provide a good compromise between accuracy and computational efficiency in describing the ESP of small organic molecules undergoing conformational changes. For the point charge models, the inclusion of polarizability reduced the the average root mean square error of ESP over the test set by 4-10%.

  12. A Combined Theoretical and Experimental Study for Silver Electroplating

    Science.gov (United States)

    Liu, Anmin; Ren, Xuefeng; An, Maozhong; Zhang, Jinqiu; Yang, Peixia; Wang, Bo; Zhu, Yongming; Wang, Chong

    2014-01-01

    A novel method combined theoretical and experimental study for environmental friendly silver electroplating was introduced. Quantum chemical calculations and molecular dynamic (MD) simulations were employed for predicting the behaviour and function of the complexing agents. Electronic properties, orbital information, and single point energies of the 5,5-dimethylhydantoin (DMH), nicotinic acid (NA), as well as their silver(I)-complexes were provided by quantum chemical calculations based on density functional theory (DFT). Adsorption behaviors of the agents on copper and silver surfaces were investigated using MD simulations. Basing on the data of quantum chemical calculations and MD simulations, we believed that DMH and NA could be the promising complexing agents for silver electroplating. The experimental results, including of electrochemical measurement and silver electroplating, further confirmed the above prediction. This efficient and versatile method thus opens a new window to study or design complexing agents for generalized metal electroplating and will vigorously promote the level of this research region.

  13. A linearization approach for the model-based analysis of combined aggregate and individual patient data.

    Science.gov (United States)

    Ravva, Patanjali; Karlsson, Mats O; French, Jonathan L

    2014-04-30

    The application of model-based meta-analysis in drug development has gained prominence recently, particularly for characterizing dose-response relationships and quantifying treatment effect sizes of competitor drugs. The models are typically nonlinear in nature and involve covariates to explain the heterogeneity in summary-level literature (or aggregate data (AD)). Inferring individual patient-level relationships from these nonlinear meta-analysis models leads to aggregation bias. Individual patient-level data (IPD) are indeed required to characterize patient-level relationships but too often this information is limited. Since combined analyses of AD and IPD allow advantage of the information they share to be taken, the models developed for AD must be derived from IPD models; in the case of linear models, the solution is a closed form, while for nonlinear models, closed form solutions do not exist. Here, we propose a linearization method based on a second order Taylor series approximation for fitting models to AD alone or combined AD and IPD. The application of this method is illustrated by an analysis of a continuous landmark endpoint, i.e., change from baseline in HbA1c at week 12, from 18 clinical trials evaluating the effects of DPP-4 inhibitors on hyperglycemia in diabetic patients. The performance of this method is demonstrated by a simulation study where the effects of varying the degree of nonlinearity and of heterogeneity in covariates (as assessed by the ratio of between-trial to within-trial variability) were studied. A dose-response relationship using an Emax model with linear and nonlinear effects of covariates on the emax parameter was used to simulate data. The simulation results showed that when an IPD model is simply used for modeling AD, the bias in the emax parameter estimate increased noticeably with an increasing degree of nonlinearity in the model, with respect to covariates. When using an appropriately derived AD model, the linearization

  14. Merging Alternate Remotely-Sensed Soil Moisture Retrievals Using a Non-Static Model Combination Approach

    Directory of Open Access Journals (Sweden)

    Seokhyeon Kim

    2016-06-01

    Full Text Available Soil moisture is an important variable in the coupled hydrologic and climate system. In recent years, microwave-based soil moisture products have been shown to be a viable alternative to in situ measurements. A popular way to measure the performance of soil moisture products is to calculate the temporal correlation coefficient (R against in situ measurements or other appropriate reference datasets. In this study, an existing linear combination method improving R was modified to allow for a non-static or nonstationary model combination as the basis for improving remotely-sensed surface soil moisture. Previous research had noted that two soil moisture products retrieved using the Japan Aerospace Exploration Agency (JAXA and Land Parameter Retrieval Model (LPRM algorithms from the same Advanced Microwave Scanning Radiometer 2 (AMSR2 sensor are spatially complementary in terms of R against a suitable reference over a fixed period. Accordingly, a linear combination was proposed to maximize R using a set of spatially-varying, but temporally-fixed weights. Even though this approach showed promising results, there was room for further improvements, in particular using non-static or dynamic weights that take account of the time-varying nature of the combination algorithm being approximated. The dynamic weighting was achieved by using a moving window. A number of different window sizes was investigated. The optimal weighting factors were determined for the data lying within the moving window and then used to dynamically combine the two parent products. We show improved performance for the dynamically-combined product over the static linear combination. Generally, shorter time windows outperform the static approach, and a 60-day time window is suggested to be the optimum. Results were validated against in situ measurements collected from 124 stations over different continents. The mean R of the dynamically-combined products was found to be 0.57 and 0

  15. A combined gray neural network model of seasonal heating load forecast

    Institute of Scientific and Technical Information of China (English)

    QIAOXiaozhuang; YANGChangzhi

    2003-01-01

    Seasonal heating load time sequence has the double trends of increasing and fluctuating, so it''s difficult to select a model to forecast it. In this paper, a combined model of gray model and artificial neural network model was presented to forecast seasonal heating load. A concrete model was established and was verified through actual examples.

  16. Combining 3d Volume and Mesh Models for Representing Complicated Heritage Buildings

    Science.gov (United States)

    Tsai, F.; Chang, H.; Lin, Y.-W.

    2017-08-01

    This study developed a simple but effective strategy to combine 3D volume and mesh models for representing complicated heritage buildings and structures. The idea is to seamlessly integrate 3D parametric or polyhedral models and mesh-based digital surfaces to generate a hybrid 3D model that can take advantages of both modeling methods. The proposed hybrid model generation framework is separated into three phases. Firstly, after acquiring or generating 3D point clouds of the target, these 3D points are partitioned into different groups. Secondly, a parametric or polyhedral model of each group is generated based on plane and surface fitting algorithms to represent the basic structure of that region. A "bare-bones" model of the target can subsequently be constructed by connecting all 3D volume element models. In the third phase, the constructed bare-bones model is used as a mask to remove points enclosed by the bare-bones model from the original point clouds. The remaining points are then connected to form 3D surface mesh patches. The boundary points of each surface patch are identified and these boundary points are projected onto the surfaces of the bare-bones model. Finally, new meshes are created to connect the projected points and original mesh boundaries to integrate the mesh surfaces with the 3D volume model. The proposed method was applied to an open-source point cloud data set and point clouds of a local historical structure. Preliminary results indicated that the reconstructed hybrid models using the proposed method can retain both fundamental 3D volume characteristics and accurate geometric appearance with fine details. The reconstructed hybrid models can also be used to represent targets in different levels of detail according to user and system requirements in different applications.

  17. General Quantum Modeling of Combining Concepts: A Quantum Field Model in Fock Space

    CERN Document Server

    Aerts, Diederik

    2007-01-01

    We extend a quantum model in Hilbert space developed in Aerts (2007a) into a quantum field theoric model in Fock space for the modeling of the combination of concepts. Items and concepts are represented by vectors in Fock space and membership weights of items are modeled by quantum probabilities. We apply this theory to model the disjunction of concepts and show that the predictions of our theory for the membership weights of items regarding the disjunction of concepts match with great accuracy the complete set of results of an experiment conducted by Hampton (1988b). It are the quantum effects of interference and superposition of that are at the origin of the effects of overextension and underextension observed by Hampton as deviations from a classical use of the disjunction. It is essential for the perfect matches we obtain between the predictions of the quantum field model and Hampton's experimental data that items can be in superpositions of `different numbers states' which proves that the genuine structu...

  18. Nonlinear model predictive control using parameter varying BP-ARX combination model

    Science.gov (United States)

    Yang, J.-F.; Xiao, L.-F.; Qian, J.-X.; Li, H.

    2012-03-01

    A novel back-propagation AutoRegressive with eXternal input (BP-ARX) combination model is constructed for model predictive control (MPC) of MIMO nonlinear systems, whose steady-state relation between inputs and outputs can be obtained. The BP neural network represents the steady-state relation, and the ARX model represents the linear dynamic relation between inputs and outputs of the nonlinear systems. The BP-ARX model is a global model and is identified offline, while the parameters of the ARX model are rescaled online according to BP neural network and operating data. Sequential quadratic programming is employed to solve the quadratic objective function online, and a shift coefficient is defined to constrain the effect time of the recursive least-squares algorithm. Thus, a parameter varying nonlinear MPC (PVNMPC) algorithm that responds quickly to large changes in system set-points and shows good dynamic performance when system outputs approach set-points is proposed. Simulation results in a multivariable stirred tank and a multivariable pH neutralisation process illustrate the applicability of the proposed method and comparisons of the control effect between PVNMPC and multivariable recursive generalised predictive controller are also performed.

  19. Cognitive Virtualization: Combining Cognitive Models and Virtual Environments

    Energy Technology Data Exchange (ETDEWEB)

    Tuan Q. Tran; David I. Gertman; Donald D. Dudenhoeffer; Ronald L. Boring; Alan R. Mecham

    2007-08-01

    3D manikins are often used in visualizations to model human activity in complex settings. Manikins assist in developing understanding of human actions, movements and routines in a variety of different environments representing new conceptual designs. One such environment is a nuclear power plant control room, here they have the potential to be used to simulate more precise ergonomic assessments of human work stations. Next generation control rooms will pose numerous challenges for system designers. The manikin modeling approach by itself, however, may be insufficient for dealing with the desired technical advancements and challenges of next generation automated systems. Uncertainty regarding effective staffing levels; and the potential for negative human performance consequences in the presence of advanced automated systems (e.g., reduced vigilance, poor situation awareness, mistrust or blind faith in automation, higher information load and increased complexity) call for further research. Baseline assessment of novel control room equipment(s) and configurations needs to be conducted. These design uncertainties can be reduced through complementary analysis that merges ergonomic manikin models with models of higher cognitive functions, such as attention, memory, decision-making, and problem-solving. This paper will discuss recent advancements in merging a theoretical-driven cognitive modeling framework within a 3D visualization modeling tool to evaluate of next generation control room human factors and ergonomic assessment. Though this discussion primary focuses on control room design, the application for such a merger between 3D visualization and cognitive modeling can be extended to various areas of focus such as training and scenario planning.

  20. Forecasting RMB Exchange Rate Based on a Nonlinear Combination Model of ARFIMA, SVM, and BPNN

    Directory of Open Access Journals (Sweden)

    Chi Xie

    2015-01-01

    Full Text Available There are various models to predict financial time series like the RMB exchange rate. In this paper, considering the complex characteristics of RMB exchange rate, we build a nonlinear combination model of the autoregressive fractionally integrated moving average (ARFIMA model, the support vector machine (SVM model, and the back-propagation neural network (BPNN model to forecast the RMB exchange rate. The basic idea of the nonlinear combination model (NCM is to make the prediction more effective by combining different models’ advantages, and the weight of the combination model is determined by a nonlinear weighted mechanism. The RMB exchange rate against US dollar (RMB/USD and the RMB exchange rate against Euro (RMB/EUR are used as the empirical examples to evaluate the performance of NCM. The results show that the prediction performance of the nonlinear combination model is better than the single models and the linear combination models, and the nonlinear combination model is suitable for the prediction of the special time series, such as the RMB exchange rate.

  1. Local Inflammation in Fracture Hematoma: Results from a Combined Trauma Model in Pigs

    Directory of Open Access Journals (Sweden)

    K. Horst

    2015-01-01

    Full Text Available Background. Previous studies showed significant interaction between the local and systemic inflammatory response after severe trauma in small animal models. The purpose of this study was to establish a new combined trauma model in pigs to investigate fracture-associated local inflammation and gain information about the early inflammatory stages after polytrauma. Material and Methods. Combined trauma consisted of tibial fracture, lung contusion, liver laceration, and controlled hemorrhage. Animals were mechanically ventilated and under ICU-monitoring for 48 h. Blood and fracture hematoma samples were collected during the time course of the study. Local and systemic levels of serum cytokines and diverse alarmins were measured by ELISA kit. Results. A statistical significant difference in the systemic serum values of IL-6 and HMGB1 was observed when compared to the sham. Moreover, there was a statistical significant difference in the serum values of the fracture hematoma of IL-6, IL-8, IL-10, and HMGB1 when compared to the systemic inflammatory response. However a decrease of local proinflammatory concentrations was observed while anti-inflammatory mediators increased. Conclusion. Our data showed a time-dependent activation of the local and systemic inflammatory response. Indeed it is the first study focusing on the local and systemic inflammatory response to multiple-trauma in a large animal model.

  2. Modeling Social Influence via Combined Centralized and Distributed Planning Control

    Science.gov (United States)

    Vaccaro, James; Guest, Clark

    2010-01-01

    Real world events are driven by a mixture of both centralized and distributed control of individual agents based on their situational context and internal make up. For example, some people have partial allegiances to multiple, contradictory authorities, as well as to their own goals and principles. This can create a cognitive dissonance that can be exploited by an appropriately directed psychological influence operation (PSYOP). An Autonomous Dynamic Planning and Execution (ADP&E) approach is proposed for modeling both the unperturbed context as well as its reaction to various PSYOP interventions. As an illustrative example, the unrest surrounding the Iranian elections in the summer of 2009 is described in terms applicable to an ADP&E modeling approach. Aspects of the ADP&E modeling process are discussed to illustrate its application and advantages for this example.

  3. COMBINING SCENE MODEL AND FUSION FOR NIGHT VIDEO ENHANCEMENT

    Institute of Scientific and Technical Information of China (English)

    Li Jing; Yang Tao; Pan Quan; Cheng Yongmei

    2009-01-01

    This paper presents a video context enhancement method for night surveillance. The basic idea is to extract and fuse the meaningful information of video sequence captured from a fixed camera under different illuminations. A unique characteristic of the algorithm is to separate the image context into two classes and estimate them in different ways. One class contains basic surrounding scene information and scene model, which is obtained via background modeling and object tracking in daytime video sequence. The other class is extracted from nighttime video, including frequently moving region, high illumination region and high gradient region. The scene model and pixel-wise difference method are used to segment the three regions. A shift-invariant discrete wavelet based image fusion technique is used to integral all those context information in the final result. Experiment results demonstrate that the proposed approach can provide much more details and meaningful information for nighttime video.

  4. A novel combined model of discrete and mixture phases for nanoparticles in convective turbulent flow

    Science.gov (United States)

    Mahdavi, Mostafa; Sharifpur, Mohsen; Meyer, Josua P.

    2017-08-01

    In this study, a new combined model is presented to study the flow and discrete phase features of nano-size particles for turbulent convection in a horizontal tube. Due to the complexity and many phenomena involved in particle-liquid turbulent flows, the conventional models are not able to properly predict some hidden aspects of the flow. Therefore, a new form of Brownian force is implemented in the discrete phase model to predict the migration of the particles as well as energy equation has modified for particles. Then, the final results are exported to the mixture equations of the flow. The effects of the mass diffusion due to thermophoresis, Brownian motion, and turbulent dispersion are implemented as source terms in equations. The results are compared with the experimental measurements from the literature and are adequately validated. The accuracy of predicted heat transfer and friction coefficients is also discussed versus measurements. The migration of the particles toward the centre of the tube is properly captured. The results show the non-uniform distribution of particles in the turbulent flow due to strong turbulent dispersion. The proposed combined model can open new viewpoints of particle-fluid interaction flows.

  5. Infectious diseases among animals : combining models with data

    NARCIS (Netherlands)

    Koeijer, A.A. de

    2003-01-01

    To eradicate or control the spread of infectious diseases, knowledge on the spread of the infection between (groups of) animals is necessary. Models can include such information and can subsequently be used to observe the efficacy of various control measures in fighting the infection. However, the a

  6. When one model is not enough: combining epistemic tools in systems biology.

    Science.gov (United States)

    Green, Sara

    2013-06-01

    In recent years, the philosophical focus of the modeling literature has shifted from descriptions of general properties of models to an interest in different model functions. It has been argued that the diversity of models and their correspondingly different epistemic goals are important for developing intelligible scientific theories (Leonelli, 2007; Levins, 2006). However, more knowledge is needed on how a combination of different epistemic means can generate and stabilize new entities in science. This paper will draw on Rheinberger's practice-oriented account of knowledge production. The conceptual repertoire of Rheinberger's historical epistemology offers important insights for an analysis of the modelling practice. I illustrate this with a case study on network modeling in systems biology where engineering approaches are applied to the study of biological systems. I shall argue that the use of multiple representational means is an essential part of the dynamic of knowledge generation. It is because of-rather than in spite of-the diversity of constraints of different models that the interlocking use of different epistemic means creates a potential for knowledge production.

  7. Experimental Study on Strategy of Combining SAT Algorithms

    Institute of Scientific and Technical Information of China (English)

    吕卫锋; 张玉平

    1998-01-01

    The effectiveness of many SAT algorithms is mainly reflected by their significant performances on one or several classes of specific SAT problems.Different kinds of SAT algorithms all have their own hard instances respectively.Therefore,to get the better performance on all kinds of problems,SAT solver should know how to select different algorithms according to the feature of instances.In this paper the differences of several effective SAT algorithms are analyzed and two new parameters φand δ are proposed to characterize the feature of SAT instances.Experiments are performed to study the relationship between SAT algorithms and some statistical parameters including φ,δ.Based on this analysis,a strategy is presented for designing a faster SAT tester by carefully combining some existing SAT algorithms.With this strategy,a faster SAT tester to solve many kinds of SAT problem is obtained.

  8. Learning to Combine Collection-centric and Document-centric Models for Resource Selection

    Science.gov (United States)

    2014-11-01

    Learning to Combine Collection-centric and Document-centric Models for Resource Selection Krisztian Balog University of Stavanger krisztian.balog...where we employ a learning-to-rank approach to combine various (instantiations of) resource rank- ing models. Further, we show that vertical selec...on all metrics (Demeester et al., 2014). We also experimented with the combination of the CC and DC strategies in our par- ticipation last year, using

  9. Analysis of heterogeneity and epistasis in physiological mixed populations by combined structural equation modelling and latent class analysis

    DEFF Research Database (Denmark)

    Fenger, Mogens; Linneberg, A.; Werge, Thomas Mears

    2008-01-01

    and genetic variations of such networks. METHODS: In this study on type 2 diabetes mellitus, heterogeneity was resolved in a latent class framework combined with structural equation modelling using phenotypic indicators of distinct physiological processes. We modelled the clinical condition "the metabolic...

  10. Microbial dynamics in a High Arctic glacier forefield: a combined field, laboratory, and modelling approach

    Science.gov (United States)

    Bradley, James A.; Arndt, Sandra; Šabacká, Marie; Benning, Liane G.; Barker, Gary L.; Blacker, Joshua J.; Yallop, Marian L.; Wright, Katherine E.; Bellas, Christopher M.; Telling, Jonathan; Tranter, Martyn; Anesio, Alexandre M.

    2016-10-01

    Modelling the development of soils in glacier forefields is necessary in order to assess how microbial and geochemical processes interact and shape soil development in response to glacier retreat. Furthermore, such models can help us predict microbial growth and the fate of Arctic soils in an increasingly ice-free future. Here, for the first time, we combined field sampling with laboratory analyses and numerical modelling to investigate microbial community dynamics in oligotrophic proglacial soils in Svalbard. We measured low bacterial growth rates and growth efficiencies (relative to estimates from Alpine glacier forefields) and high sensitivity of bacterial growth rates to soil temperature (relative to temperate soils). We used these laboratory measurements to inform parameter values in a new numerical model and significantly refined predictions of microbial and biogeochemical dynamics of soil development over a period of roughly 120 years. The model predicted the observed accumulation of autotrophic and heterotrophic biomass. Genomic data indicated that initial microbial communities were dominated by bacteria derived from the glacial environment, whereas older soils hosted a mixed community of autotrophic and heterotrophic bacteria. This finding was simulated by the numerical model, which showed that active microbial communities play key roles in fixing and recycling carbon and nutrients. We also demonstrated the role of allochthonous carbon and microbial necromass in sustaining a pool of organic material, despite high heterotrophic activity in older soils. This combined field, laboratory, and modelling approach demonstrates the value of integrated model-data studies to understand and quantify the functioning of the microbial community in an emerging High Arctic soil ecosystem.

  11. Patients’ views about treatment with combination therapy for Rheumatoid Arthritis: a comparative qualitative study

    Directory of Open Access Journals (Sweden)

    Lempp Heidi

    2012-10-01

    Full Text Available Abstract Background Combinations of disease-modifying anti-rheumatic drugs (DMARDs are increasingly used to control active rheumatoid arthritis (RA; however there is little information about patients’ perspectives, their expectations, concerns and experiences of this intensive treatment. Method We interviewed a quota sample of 18 patients from a single tertiary outpatient clinic, stratified by gender, ethnicity and age, based on the outpatient clinic population. Patients with early RA (2 years received combined conventional DMARDs or DMARDs with biologics. Results Four main themes emerged from the analytical framework: (i patients’ expectations about the combined treatment focuses mainly on physical symptoms; (ii the impact of the treatment on quality of life varied with the new medication in both groups (iii concerns about new interventions concentrated mainly on potential side effects; and (iv combination therapy can be self-managed in close collaboration with clinic staff, but this requires individualised management approaches. These themes resonate with von Korff’s collaborative management of chronic illness model. Conclusion To our knowledge this is the first qualitative study that examined systematically in patients with early and established RA their expectations, impact on quality of life, concerns about side effects and the management of the treatment when taking combined medication with DMARDs or DMARDs and biologics. Patients have generally positive views of combination DMARDs. Within routine practice settings, achieving medication concordance with complex combined DMARD regimens is challenging, and the concerns vary between patients; careful individual assessments are essential to successfully deliver such intensive treatment.

  12. Modelling of combined cycle power plants using biomass

    Energy Technology Data Exchange (ETDEWEB)

    Jurado, F.; Cano, A. [University of Jaen (Spain). Dept. of Electrical Engineering; Carpio, J. [Universidad Nacional de Educacion a Distancia, Madrid (Spain). Dept. of Electrical and Computer Engineering

    2003-04-01

    The olive tree in Spain can generate large quantities of by-product biomass suitable for gasification. Gasification technologies under development would enable these fuels to be used in gas turbines. Biomass conversion to a clean essentially ash-free form, usually by gasification and purification, is necessary to obtain high efficiency. This paper reports results of detailed full-load performance modelling of cogeneration systems based on gasifier/gas turbine technologies. (Author)

  13. Implementation of a combined algorithm designed to increase the reliability of information systems: simulation modeling

    Science.gov (United States)

    Popov, A.; Zolotarev, V.; Bychkov, S.

    2016-11-01

    This paper examines the results of experimental studies of a previously submitted combined algorithm designed to increase the reliability of information systems. The data that illustrates the organization and conduct of the studies is provided. Within the framework of a comparison of As a part of the study conducted, the comparison of the experimental data of simulation modeling and the data of the functioning of the real information system was made. The hypothesis of the homogeneity of the logical structure of the information systems was formulated, thus enabling to reconfigure the algorithm presented, - more specifically, to transform it into the model for the analysis and prediction of arbitrary information systems. The results presented can be used for further research in this direction. The data of the opportunity to predict the functioning of the information systems can be used for strategic and economic planning. The algorithm can be used as a means for providing information security.

  14. A polytomous conditional likelihood approach for combining matched and unmatched case-control studies.

    Science.gov (United States)

    Gebregziabher, Mulugeta; Guimaraes, Paulo; Cozen, Wendy; Conti, David V

    2010-04-30

    In genetic association studies it is becoming increasingly imperative to have large sample sizes to identify and replicate genetic effects. To achieve these sample sizes, many research initiatives are encouraging the collaboration and combination of several existing matched and unmatched case-control studies. Thus, it is becoming more common to compare multiple sets of controls with the same case group or multiple case groups to validate or confirm a positive or negative finding. Usually, a naive approach of fitting separate models for each case-control comparison is used to make inference about disease-exposure association. But, this approach does not make use of all the observed data and hence could lead to inconsistent results. The problem is compounded when a common case group is used in each case-control comparison. An alternative to fitting separate models is to use a polytomous logistic model but, this model does not combine matched and unmatched case-control data. Thus, we propose a polytomous logistic regression approach based on a latent group indicator and a conditional likelihood to do a combined analysis of matched and unmatched case-control data. We use simulation studies to evaluate the performance of the proposed method and a case-control study of multiple myeloma and Inter-Leukin-6 as an example. Our results indicate that the proposed method leads to a more efficient homogeneity test and a pooled estimate with smaller standard error.

  15. Simulation of neuro-fuzzy model for optimization of combine header setting

    Directory of Open Access Journals (Sweden)

    S Zareei

    2016-09-01

    Full Text Available Introduction The noticeable proportion of producing wheat losses occur during production and consumption steps and the loss due to harvesting with combine harvester is regarded as one of the main factors. A grain combines harvester consists of different sets of equipment and one of the most important parts is the header which comprises more than 50% of the entire harvesting losses. Some researchers have presented regression equation to estimate grain loss of combine harvester. The results of their study indicated that grain moisture content, reel index, cutter bar speed, service life of cutter bar, tine spacing, tine clearance over cutter bar, stem length were the major parameters affecting the losses. On the other hand, there are several researchswhich have used the variety of artificial intelligence methods in the different aspects of combine harvester. In neuro-fuzzy control systems, membership functions and if-then rules were defined through neural networks. Sugeno- type fuzzy inference model was applied to generate fuzzy rules from a given input-output data set due to its less time-consuming and mathematically tractable defuzzification operation for sample data-based fuzzy modeling. In this study, neuro-fuzzy model was applied to develop forecasting models which can predict the combine header loss for each set of the header parameter adjustments related to site-specific information and therefore can minimize the header loss. Materials and Methods The field experiment was conducted during the harvesting season of 2011 at the research station of the Faulty of Agriculture, Shiraz University, Shiraz, Iran. The wheat field (CV. Shiraz was harvested with a Claas Lexion-510 combine harvester. The factors which were selected as main factors influenced the header performance were three levels of reel index (RI (forward speed of combine harvester divided by peripheral speed of reel (1, 1.2, 1.5, three levels of cutting height (CH(25, 30, 35 cm, three

  16. Modelling of sediment transport and morphological evolution under the combined action of waves and currents

    Directory of Open Access Journals (Sweden)

    G. Franz

    2017-09-01

    Full Text Available Coastal defence structures are often constructed to prevent beach erosion. However, poorly designed structures may cause serious erosion problems in the downdrift direction. Morphological models are useful tools to predict such impacts and assess the efficiency of defence structures for different scenarios. Nevertheless, morphological modelling is still a topic under intense research effort. The processes simulated by a morphological model depend on model complexity. For instance, undertow currents are neglected in coastal area models (2DH, which is a limitation for simulating the evolution of beach profiles for long periods. Model limitations are generally overcome by predefining invariant equilibrium profiles that are allowed to shift offshore or onshore. A more flexible approach is described in this paper, which can be generalised to 3-D models. The present work is based on the coupling of the MOHID modelling system and the SWAN wave model. The impacts of different designs of detached breakwaters and groynes were simulated in a schematic beach configuration following a 2DH approach. The results of bathymetry evolution are in agreement with the patterns found in the literature for several existing structures. The model was also tested in a 3-D test case to simulate the formation of sandbars by undertow currents. The findings of this work confirmed the applicability of the MOHID modelling system to study sediment transport and morphological changes in coastal zones under the combined action of waves and currents. The same modelling methodology was applied to a coastal zone (Costa da Caparica located at the mouth of a mesotidal estuary (Tagus Estuary, Portugal to evaluate the hydrodynamics and sediment transport both in calm water conditions and during events of highly energetic waves. The MOHID code is available in the GitHub repository.

  17. Modelling of sediment transport and morphological evolution under the combined action of waves and currents

    Science.gov (United States)

    Franz, Guilherme; Delpey, Matthias T.; Brito, David; Pinto, Lígia; Leitão, Paulo; Neves, Ramiro

    2017-09-01

    Coastal defence structures are often constructed to prevent beach erosion. However, poorly designed structures may cause serious erosion problems in the downdrift direction. Morphological models are useful tools to predict such impacts and assess the efficiency of defence structures for different scenarios. Nevertheless, morphological modelling is still a topic under intense research effort. The processes simulated by a morphological model depend on model complexity. For instance, undertow currents are neglected in coastal area models (2DH), which is a limitation for simulating the evolution of beach profiles for long periods. Model limitations are generally overcome by predefining invariant equilibrium profiles that are allowed to shift offshore or onshore. A more flexible approach is described in this paper, which can be generalised to 3-D models. The present work is based on the coupling of the MOHID modelling system and the SWAN wave model. The impacts of different designs of detached breakwaters and groynes were simulated in a schematic beach configuration following a 2DH approach. The results of bathymetry evolution are in agreement with the patterns found in the literature for several existing structures. The model was also tested in a 3-D test case to simulate the formation of sandbars by undertow currents. The findings of this work confirmed the applicability of the MOHID modelling system to study sediment transport and morphological changes in coastal zones under the combined action of waves and currents. The same modelling methodology was applied to a coastal zone (Costa da Caparica) located at the mouth of a mesotidal estuary (Tagus Estuary, Portugal) to evaluate the hydrodynamics and sediment transport both in calm water conditions and during events of highly energetic waves. The MOHID code is available in the GitHub repository.

  18. Dosage and Dose Schedule Screening of Drug Combinations in Agent-Based Models Reveals Hidden Synergies.

    Science.gov (United States)

    Barros de Andrade E Sousa, Lisa C; Kühn, Clemens; Tyc, Katarzyna M; Klipp, Edda

    2015-01-01

    The fungus Candida albicans is the most common causative agent of human fungal infections and better drugs or drug combination strategies are urgently needed. Here, we present an agent-based model of the interplay of C. albicans with the host immune system and with the microflora of the host. We took into account the morphological change of C. albicans from the yeast to hyphae form and its dynamics during infection. The model allowed us to follow the dynamics of fungal growth and morphology, of the immune cells and of microflora in different perturbing situations. We specifically focused on the consequences of microflora reduction following antibiotic treatment. Using the agent-based model, different drug types have been tested for their effectiveness, namely drugs that inhibit cell division and drugs that constrain the yeast-to-hyphae transition. Applied individually, the division drug turned out to successfully decrease hyphae while the transition drug leads to a burst in hyphae after the end of the treatment. To evaluate the effect of different drug combinations, doses, and schedules, we introduced a measure for the return to a healthy state, the infection score. Using this measure, we found that the addition of a transition drug to a division drug treatment can improve the treatment reliability while minimizing treatment duration and drug dosage. In this work we present a theoretical study. Although our model has not been calibrated to quantitative experimental data, the technique of computationally identifying synergistic treatment combinations in an agent based model exemplifies the importance of computational techniques in translational research.

  19. Dosage and dose schedule screening of drug combinations in agent-based models reveals hidden synergies

    Directory of Open Access Journals (Sweden)

    Lisa Corina Barros de Andrade e Sousa1

    2016-01-01

    Full Text Available The fungus Candida albicans is the most common causative agent of human fungal infections and better drugs or drug combination strategies are urgently needed. Here, we present an agent-based model of the interplay of C. albicans with the host immune system and with the microflora of the host. We took into account the morphological change of C. albicans from the yeast to hyphae form and its dynamics during infection. The model allowed us to follow the dynamics of fungal growth and morphology, of the immune cells and of microflora in different perturbing situations. We specifically focused on the consequences of microflora reduction following antibiotic treatment. Using the agent-based model, different drug types have been tested for their effectiveness, namely drugs that inhibit cell division and drugs that constrain the yeast-to-hyphae transition. Applied individually, the division drug turned out to successfully decrease hyphae while the transition drug leads to a burst in hyphae after the end of the treatment. To evaluate the effect of different drug combinations, doses, and schedules, we introduced a measure for the return to a healthy state, the infection score. Using this measure, we found that the addition of a transition drug to a division drug treatment can improve the treatment reliability while minimizing treatment duration and drug dosage. In this work we present a theoretical study. Although our model has not been calibrated to quantitative experimental data, the technique of computationally identifying synergistic treatment combinations in an agent based model exemplifies the importance of computational techniques in translational research.

  20. A Network Inversion Filter combining GNSS and InSAR for tectonic slip modeling

    Science.gov (United States)

    Bekaert, D. P. S.; Segall, P.; Wright, T. J.; Hooper, A. J.

    2016-03-01

    Studies of the earthquake cycle benefit from long-term time-dependent slip modeling, as it can be a powerful means to improve our understanding on the interaction of earthquake cycle processes such as interseismic, coseismic, post seismic, and aseismic slip. Observations from Interferometric Synthetic Aperture Radar (InSAR) allow us to model slip at depth with a higher spatial resolution than when using Global Navigation Satellite Systems (GNSS) alone. While the temporal resolution of InSAR has typically been limited, the recent fleet of SAR satellites including Sentinel-1, COSMO-SkyMED, and RADARSAT-2 permits the use of InSAR for time-dependent slip modeling at intervals of a few days when combined. With the vast amount of SAR data available, simultaneous data inversion of all epochs becomes challenging. Here we expanded the original network inversion filter to include InSAR observations of surface displacements in addition to GNSS. In the Network Inversion Filter (NIF) framework, geodetic observations are limited to those of a given epoch, with a stochastic model describing slip evolution over time. The combination of the Kalman forward filtering and backward smoothing allows all geodetic observations to constrain the complete observation period. Combining GNSS and InSAR allows modeling of time-dependent slip at unprecedented spatial resolution. We validate the approach with a simulation of the 2006 Guerrero slow slip event. We highlight the importance of including InSAR covariance information and demonstrate that InSAR provides an additional constraint on the spatial extent of the slow slip.

  1. Multiplicity fluctuation and correlation of identified baryons in a quark combination model

    Science.gov (United States)

    Song, Jun; Li, Hai-hong; Wang, Rui-qin; Shao, Feng-lan

    2017-01-01

    The dynamical multiplicity fluctuations and correlations of identified baryons and antibaryons produced by the hadronization of a bulk quark system are systematically studied in a quark combination model. Starting from the most basic dynamics of the quark combination which is necessary for multiplicity study, we analyze moments (variance, skewness, and kurtosis) of inclusive multiplicity distributions of identified baryons, two-baryon multiplicity correlations, and baryon-antibaryon multiplicity correlations after the hadronization of a quark system with given quark number and antiquark number. We obtain a series of interesting results, e.g., binomial behavior of multiplicity moments, coinciding flavor-dependent two-baryon correlation, and universal baryon-antibaryon correlation, which can be regarded as general features of the quark combination. We further take into account correlations and fluctuations of quark numbers before hadronization and study their influence on multiple production of baryons and antibaryons. We find that quark number fluctuations and flavor conservation lead to a series of important results such as the negative p Ω¯ + multiplicity correlation and universal two-baryon correlations. We also study the influence of resonance decays in order to compare our results with future experimental data in ultrarelativistic heavy ion collisions at the Large Hadron Collider.

  2. Steady state speed distribution analysis for a combined cellular automaton traffic model

    Institute of Scientific and Technical Information of China (English)

    Wang Jun-Feng; Chen Gui-Sheng; Liu Jin

    2008-01-01

    Cellular Automaton (CA) baaed traffic flow models have been extensively studied due to their effectiveness and simplicity in recent years. This paper develops a discrete time Markov chain (DTMC) analytical framework for a Nagel-Schreckenberg and Fukui-Ishibashi combined CA model (W2H traffic flow model) from microscopic point of view to capture the macroscopic steady state speed distributions. The inter-vehicle spacing Markov chain and the steady state speed Markov chain are proved to be irreducible and ergodie. The theoretical speed probability distributions depending on the traffic density and stochastic delay probability are in good accordance with numerical simulations. The derived fundamental diagram of the average speed from theoretical speed distributions is equivalent to the results in the previous work.

  3. On the cluster composition of supercritical water combining molecular modeling and vibrational spectroscopic data.

    Science.gov (United States)

    Tassaing, T; Garrain, P A; Bégué, D; Baraille, I

    2010-07-21

    The present study is aimed at a detailed analysis of supercritical water structure based on the combination of experimental vibrational spectra as well as molecular modeling calculations of isolated water clusters. We propose an equilibrium cluster composition model where supercritical water is considered as an ideal mixture of small water clusters (n=1-3) at the chemical equilibrium and the vibrational spectra are expected to result from the superposition of the spectra of the individual clusters, Thus, it was possible to extract from the decomposition of the midinfrared spectra the evolution of the partition of clusters in supercritical water as a function of density. The cluster composition predicted by this model was found to be quantitatively consistent with the near infrared and Raman spectra of supercritical water analyzed using the same procedure. We emphasize that such methodology could be applied to determine the portion of cluster in water in a wider thermodynamic range as well as in more complex aqueous supercritical solutions.

  4. The Combination Forecasting of Electricity Price Based on Price Spikes Processing: A Case Study in South Australia

    Directory of Open Access Journals (Sweden)

    Jianzhou Wang

    2014-01-01

    Full Text Available Electricity price forecasting holds very important position in the electricity market. Inaccurate price forecasting may cause energy waste and management chaos in the electricity market. However, electricity price forecasting has always been regarded as one of the largest challenges in the electricity market because it shows high volatility, which makes electricity price forecasting difficult. This paper proposes the use of artificial intelligence optimization combination forecasting models based on preprocessing data, called “chaos particles optimization (CPSO weight-determined combination models.” These models allow for the weight of the combined model to take values of [-1,1]. In the proposed models, the density-based spatial clustering of applications with noise (DBSCAN algorithm is used to identify outliers, and the outliers are replaced by a new data-produced linear interpolation function. The proposed CPSO weight-determined combination models are then used to forecast the projected future electricity price. In this case study, the electricity price data of South Australia are simulated. The results indicate that, while the weight of the combined model takes values of [-1,1], the proposed combination model can always provide adaptive, reliable, and comparatively accurate forecast results in comparison to traditional combination models.

  5. Melanoma: A model for testing new agents in combination therapies

    Directory of Open Access Journals (Sweden)

    Streicher Howard Z

    2010-04-01

    Full Text Available Abstract Treatment for both early and advanced melanoma has changed little since the introduction of interferon and IL-2 in the early 1990s. Recent data from trials testing targeted agents or immune modulators suggest the promise of new strategies to treat patients with advanced melanoma. These include a new generation of B-RAF inhibitors with greater selectivity for the mutant protein, c-Kit inhibitors, anti-angiogenesis agents, the immune modulators anti-CTLA4, anti-PD-1, and anti-CD40, and adoptive cellular therapies. The high success rate of mutant B-RAF and c-Kit inhibitors relies on the selection of patients with corresponding mutations. However, although response rates with small molecule inhibitors are high, most are not durable. Moreover, for a large subset of patients, reliable predictive biomarkers especially for immunologic modulators have not yet been identified. Progress may also depend on identifying additional molecular targets, which in turn depends upon a better understanding of the mechanisms leading to response or resistance. More challenging but equally important will be understanding how to optimize the treatment of individual patients using these active agents sequentially or in combination with each other, with other experimental treatment, or with traditional anticancer modalities such as chemotherapy, radiation, or surgery. Compared to the standard approach of developing new single agents for licensing in advanced disease, the identification and validation of patient specific and multi-modality treatments will require increased involvement by several stakeholders in designing trials aimed at identifying, even in early stages of drug development, the most effective way to use molecularly guided approaches to treat tumors as they evolve over time.

  6. Comparative numerical and experimental study of two combined wind and wave energy concepts

    Directory of Open Access Journals (Sweden)

    Zhen Gao

    2016-01-01

    Full Text Available With a successful and rapid development of offshore wind industry and increased research activities on wave energy conversion in recent years, there is an interest in investigating the technological and economic feasibility of combining offshore wind turbines (WTs with wave energy converters (WECs. In the EU FP7 MARINA Platform project, three floating combined concepts, namely the spar torus combination (STC, the semi-submersible flap combination (SFC and the oscillating water column (OWC array with a wind turbine, were selected and studied in detail by numerical and experimental methods. This paper summarizes the numerical modeling and analysis of the two concepts: STC and SFC, the model tests at a 1:50 scale under simultaneous wave and wind excitation, as well as the comparison between the numerical and experimental results. Both operational and survival wind and wave conditions were considered. The numerical analysis was based on a time-domain global model using potential flow theory for hydrodynamics and blade element momentum theory (for SFC or simplified thrust force model (for STC for aerodynamics. Different techniques for model testing of combined wind and wave concepts were discussed with focus on modeling of wind turbines by disk or redesigned small-scale rotor and modeling of power take-off (PTO system for wave energy conversion by pneumatic damper or hydraulic rotary damper. In order to reduce the uncertainty due to scaling, the numerical analysis was performed at model scale and both the numerical and experimental results were then up-scaled to full scale for comparison. The comparison shows that the current numerical model can well predict the responses (motions, PTO forces, power production of the combined concepts for most of the cases. However, the linear hydrodynamic model is not adequate for the STC concept in extreme wave conditions with the torus fixed to the spar at the mean water level for which the wave slamming on the

  7. Analytical study of the conjecture rule for the combination of multipole effects in LHC

    CERN Document Server

    Guignard, Gilbert

    1997-01-01

    This paper summarizes the analytical investigation done on the conjecture law found by tracking for the effect on the dynamic aperture of the combination of two multipoles of various order. A one-dimensional model leading to an integrable system has been used to find closed formulae for the dynamic aperture associated with a fully distributed multipole. The combination has then been studied and the resulting expression compared with the assumed conjecture law. For integrated multipoles small with respect to the focusing strength, the conjecture appears to hold, though with an exponent different from the one expected by crude reasoning.

  8. Indatuximab ravtansine (BT062 combination treatment in multiple myeloma: pre-clinical studies

    Directory of Open Access Journals (Sweden)

    Kurt Schönfeld

    2017-01-01

    Full Text Available Abstract Indatuximab ravtansine is a monoclonal antibody-linked cytotoxic agent that specifically targets CD138-expressing cells. Monotherapy has been shown to significantly inhibit multiple myeloma tumour growth in vivo and improve host survival. Here, we show that in most cell lines tested, indatuximab ravtansine acts additively or even synergistically with clinically approved therapies for treatment of multiple myeloma. In addition, in vivo mouse xenograft models confirmed the activity of indatuximab ravtansine in combination with lenalidamide and lenalidomide/dexamethasone. Indatuximab ravtansine may therefore be a suitable combination partner for multiple myeloma, and a clinical study is ongoing.

  9. Quantitative evaluation of the combination between cytotoxic drug and efflux transporter inhibitors based on a tumour growth inhibition model.

    Science.gov (United States)

    Sostelly, Alexandre; Payen, Léa; Guitton, Jérôme; Di Pietro, Attilio; Falson, Pierre; Honorat, Mylène; Boumendjel, Ahcène; Gèze, Annabelle; Freyer, Gilles; Tod, Michel

    2014-04-01

    ATP-Binding Cassette transporters such as ABCG2 confer resistance to various anticancer drugs including irinotecan and its active metabolite, SN38. Early quantitative evaluation of efflux transporter inhibitors-cytotoxic combination requires quantitative drug-disease models. A proof-of-concept study has been carried out for studying the effect of a new ABCG2 transporter inhibitor, MBLI87 combined to irinotecan in mice xenografted with cells overexpressing ABCG2. Mice were treated with irinotecan alone or combined to MBLI87, and tumour size was periodically measured. To model those data, a tumour growth inhibition model was developed. Unperturbed tumour growth was modelled using Simeoni's model. Drug effect kinetics was accounted for by a Kinetic-Pharmacodynamic approach. Effect of inhibitor was described with a pharmacodynamic interaction model where inhibitor enhances activity of cytotoxic. This model correctly predicted tumour growth dynamics from our study. MBLI87 increased irinotecan potency by 20% per μmol of MBLI87. This model retains enough complexity to simultaneously describe tumour growth and effect of this type of drug combination. It can thus be used as a template to early evaluate efflux transporter inhibitors in-vivo.

  10. Combining climate and energy policies: synergies or antagonism? Modeling interactions with energy efficiency instruments

    Energy Technology Data Exchange (ETDEWEB)

    Lecuyer, Oskar [EDF R and D - Efese, 1 av du General de Gaulle, 92141 Clamart (France)] [CIRED, 45 bis av de la Belle-Gabrielle, 94736 Nogent-sur-Marne (France); Bibas, Ruben [CIRED, 45 bis av de la Belle-Gabrielle, 94736 Nogent-sur-Marne (France)

    2012-01-15

    In addition to the already present Climate and Energy package, the European Union (EU) plans to include a binding target to reduce energy consumption. We analyze the rationales the EU invokes to justify such an overlapping and develop a minimal common framework to study interactions arising from the combination of instruments reducing emissions, promoting renewable energy (RE) production and reducing energy demand through energy efficiency (EE) investments. We find that although all instruments tend to reduce GHG emissions and although a price on carbon tends also to give the right incentives for RE and EE, the combination of more than one instrument leads to significant antagonisms regarding major objectives of the policy package. The model allows to show in a single framework and to quantify the antagonistic effects of the joint promotion of RE and EE. We also show and quantify the effects of this joint promotion on ETS permit price, on wholesale market price and on energy production levels. (authors)

  11. Modeling and optimization of the combined carbon dioxide reforming and partial oxidation of natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Larentis, A.L.; De Resende, N.S.; Salim, V.M.M.; Pinto, J.C. [Programa de Engenharia Quimica/COPPE/Universidade Federal do Rio de Janeiro, Cidade Universitaria, CP 68502, RJ, 21945-970 Rio de Janeiro (Brazil)

    2001-07-13

    The optimization of the combined carbon dioxide reforming and partial methane oxidation over a 1% Pt/{gamma}-Al{sub 2}O{sub 3} catalyst was studied in order to produce synthesis gas with hydrogen/carbon monoxide ratio close to 1, for applications in metallurgical and polycarbonates processes and for production of oxygenated compounds and hydrocarbons. The study was performed with the help of experimental design and two mathematical modeling approaches: empirical and phenomenological. Empirical polynomial models were employed to analyze the effects of the process variables on the response factors and the final correlation coefficients obtained were above 95%. The phenomenological model was obtained from individual mass balances and the obtained correlation coefficients were above 95% for CH{sub 4} and N{sub 2}, 90% for CO{sub 2} and H{sub 2}O and near 70% for H{sub 2} and CO. The empirical modeling approach was found to be more efficient, simpler and led to better results than those obtained with the phenomenological model approach. Therefore, the empirical modeling was used for optimization of the process operation conditions. At an oxygen/methane ratio of 0.55gmol/gmol and temperature of 950C, optimized process conditions were obtained with complete methane conversion, maximum carbon monoxide selectivity of 43% and minimum hydrogen/carbon monoxide ratio of 1.3, in absence of water.

  12. FAO-56 Dual Model Combined with Multi-Sensor Remote Sensing for Regional Evapotranspiration Estimations

    Directory of Open Access Journals (Sweden)

    Rim Amri

    2014-06-01

    Full Text Available The main goal of this study is to evaluate the potential of the FAO-56 dual technique for the estimation of regional evapotranspiration (ET and its constituent components (crop transpiration and soil evaporation, for two classes of vegetation (olives trees and cereals in the semi-arid region of the Kairouan plain in central Tunisia. The proposed approach combines the FAO-56 technique with remote sensing (optical and microwave, not only for vegetation characterization, as proposed in other studies but also for the estimation of soil evaporation, through the use of satellite moisture products. Since it is difficult to use ground flux measurements to validate remotely sensed data at regional scales, comparisons were made with the land surface model ISBA-A-gs which is a physical SVAT (Soil–Vegetation–Atmosphere Transfer model, an operational tool developed by Météo-France. It is thus shown that good results can be obtained with this relatively simple approach, based on the FAO-56 technique combined with remote sensing, to retrieve temporal variations of ET. The approach proposed for the daily mapping of evapotranspiration at 1 km resolution is approved in two steps, for the period between 1991 and 2007. In an initial step, the ISBA-A-gs soil moisture outputs are compared with ERS/WSC products. Then, the output of the FAO-56 technique is compared with the output generated by the SVAT ISBA-A-gs model.

  13. Research of combination model for prediction of the trend of outbreak of hepatitis B

    Directory of Open Access Journals (Sweden)

    Yin-ping CHEN

    2014-03-01

    Full Text Available Objective To establish a combination model of autoregressive integrated moving average model and the grey dynamics (ARIMA-GM of hepatitis B incidence rate (1/100 000 to predict the trend of outbreak of hepatitis B, as to provide a scientific basis for the early discovery of the infectious diseases for the performance of countermeasures of controlling its spread. Methods The monthly incidence of hepatitis B in Qian'an city, Hebei province, was collected from Jan 2004 to Dec 2012, and a model (ARIMA was reproduced with SPSS software. The GM (1,1 model was used to correct the residual sequence with a threshold value, and a combined forecasting model was reproduced. This combination model was used to predict the monthly incidence rate in this city in 2013. Results The model ARIMA(0,1,1(0,1,112 was established successfully and the residual sequence was a white noise sequence. Then the GM (1,1 model with a threshold of 3 was used to correct its residuals and obtain its nonlinear feature extraction of information. The forecasting model met required precision standards (C=0.673, P=0.877, the fitting accuracy of which was basically qualified. The results showed that the MAE, MAPE of the ARIMA-GM combined model were smaller than that of a single model, and the combined model could improve the prediction accuracy. Using the combined model to forecast the incidence of hepatitis B during Jan 2013 to Dec 2013, the overall trend was relatively consistent with the condition of previous years. Conclusion The ARIMA-GM combined model can better fit the incidence rate of hepatitis B with a greater accuracy than the seasonal ARIMA model. The prediction results can provide the reference for the early warning system of HBV. DOI: 10.11855/j.issn.0577-7402.2014.01.12

  14. Combination of multispectral remote sensing, variable rate technology and environmental modeling for citrus pest management.

    Science.gov (United States)

    Du, Qian; Chang, Ni-Bin; Yang, Chenghai; Srilakshmi, Kanth R

    2008-01-01

    The Lower Rio Grande Valley (LRGV) of south Texas is an agriculturally rich area supporting intensive production of vegetables, fruits, grain sorghum, and cotton. Modern agricultural practices involve the combined use of irrigation with the application of large amounts of agrochemicals to maximize crop yields. Intensive agricultural activities in past decades might have caused potential contamination of soil, surface water, and groundwater due to leaching of pesticides in the vadose zone. In an effort to promote precision farming in citrus production, this paper aims at developing an airborne multispectral technique for identifying tree health problems in a citrus grove that can be combined with variable rate technology (VRT) for required pesticide application and environmental modeling for assessment of pollution prevention. An unsupervised linear unmixing method was applied to classify the image for the grove and quantify the symptom severity for appropriate infection control. The PRZM-3 model was used to estimate environmental impacts that contribute to nonpoint source pollution with and without the use of multispectral remote sensing and VRT. Research findings using site-specific environmental assessment clearly indicate that combination of remote sensing and VRT may result in benefit to the environment by reducing the nonpoint source pollution by 92.15%. Overall, this study demonstrates the potential of precision farming for citrus production in the nexus of industrial ecology and agricultural sustainability.

  15. Combined Microencapsulated Islet Transplantation and Revascularization of Aortorenal Bypass in a Diabetic Nephropathy Rat Model

    Directory of Open Access Journals (Sweden)

    Yunqiang He

    2016-01-01

    Full Text Available Objective. Revascularization of aortorenal bypass is a preferred technique for renal artery stenosis (RAS in diabetic nephropathy (DN patients. Restenosis of graft vessels also should be considered in patients lacking good control of blood glucose. In this study, we explored a combined strategy to prevent the recurrence of RAS in the DN rat model. Methods. A model of DN was established by intraperitoneal injection of streptozotocin. Rats were divided into 4 groups: SR group, MIT group, Com group, and the untreated group. The levels of blood glucose and urine protein were measured, and changes in renal pathology were observed. The expression of monocyte chemoattractant protein-1 (MCP-1 in graft vessels was assessed by immunohistochemical staining. Histopathological staining was performed to assess the pathological changes of glomeruli and tubules. Results. The levels of urine protein and the expression of MCP-1 in graft vessels were decreased after islet transplantation. The injury of glomerular basement membrane and podocytes was significantly ameliorated. Conclusions. The combined strategy of revascularization and microencapsulated islet transplantation had multiple protective effects on diabetic nephropathy, including preventing atherosclerosis in the graft vessels and alleviating injury to the glomerular filtration barrier. This combined strategy may be helpful for DN patients with RAS.

  16. Acetylsalicylic acid combined with diclofenac inhibits cartilage degradation in rabbit models of osteoarthritis.

    Science.gov (United States)

    Liu, Jianqiang; Wu, Changshun; Wang, Dong; Wang, Laicheng; Sun, Shui

    2016-10-01

    The present study aimed to investigate the effect of different concentrations of acetylsalicylic acid combined with diclofenac on the articular cartilage of a rabbit model of osteoarthritis (OA). A total of 40 New Zealand white rabbits were divided into 5 groups. Group A was a sham-operated control group, which was treated with normal saline. Groups B-E were OA models and were treated with normal saline and acetylsalicylic acid combined with diclofenac at concentrations of 5, 10 and 20 mg/kg, respectively. A cartilage macroscopic examination and a pathological observation were performed to analyze the structure of the articular cartilage in all of the treated groups. The nitric oxide (NO) content and interleukin 1β (IL-1β) levels were detected by an enzyme-linked immunosorbent assay. In addition, the protein expression of matrix metalloproteinase 3 (MMP)-3 and MMP-13 were detected by western blot analysis. The mRNA expression of tissue inhibitor of metalloproteinases 1 (TIMP1) was detected by polymerase chain reaction (PCR). The results revealed that different concentrations of the drugs significantly reduced the scores of cartilago articularis, the NO and IL-1β levels and the protein expression of MMP-3 and MMP-13. Furthermore, PCR revealed that the mRNA expression of TIMP1 was significantly upregulated, and the effects increased with increasing drug concentration. Thus, the administration of different concentrations of acetylsalicylic acid combined with diclofenac demonstrates preventive or therapeutic effects against OA progression.

  17. High-temperature thermocline TES combining sensible and latent heat - CFD modeling and experimental validation

    Science.gov (United States)

    Zavattoni, Simone A.; Geissbühler, Lukas; Barbato, Maurizio C.; Zanganeh, Giw; Haselbacher, Andreas; Steinfeld, Aldo

    2017-06-01

    The concept of combined sensible/latent heat thermal energy storage (TES) has been exploited to mitigate an intrinsic thermocline TES systems drawback of heat transfer fluid outflow temperature reduction during discharging. In this study, the combined sensible/latent TES prototype under investigation is constituted by a packed bed of rocks and a small amount of encapsulated phase change material (AlSi12) as sensible heat and latent heat sections respectively. The thermo-fluid dynamics behavior of the combined TES prototype was analyzed by means of a computational fluid dynamics approach. Due to the small value of the characteristic vessel-to-particles diameter ratio, the effect of radial void-fraction variation, also known as channeling, was accounted for. Both the sensible and the latent heat sections of the storage were modeled as porous media under the assumption of local thermal non-equilibrium (LTNE). The commercial code ANSYS Fluent 15.0 was used to solve the model's constitutive conservation and transport equations obtaining a fairly good agreement with reference experimental measurements.

  18. Combining catchment and instream modelling to assess physical habitat quality

    DEFF Research Database (Denmark)

    Olsen, Martin

    observations showed that juvenile trout in stream Ledreborg prefered lower water depths and water velocities than juvenile trout in larger Danish streams, e.g. River Gudenå. Repeated electrofishing in the stream revealed big differences in temporal and spatial distribution of the trouts on the four reaches...... and abundance of trout on the reaches. • Comparison of reference condition minimum run-off and WUA curves suggested that summer low flow were not a limiting factor on the physical habitat quality for juvenile trout under reference conditions. • Habitat hydraulic modelling suggested that stream Ledreborg had...... the best potential physical habitat quality for trout fry and juvenile trout and the lowest potential physical habitat quality for adult trout. This finding supports previous evaluations of the stream as a trout habitat, concluding that stream Ledreborg has very few suitable habitats for adult trout...

  19. Neural Network for Combining Linear and Non-Linear Modelling of Dynamic Systems

    DEFF Research Database (Denmark)

    Madsen, Per Printz

    1994-01-01

    The purpose of this paper is to develop a method to combine linear models with MLP networks. In other words to find a method to make a non-linear and multivariable model that performs at least as good as a linear model, when the training data lacks information.......The purpose of this paper is to develop a method to combine linear models with MLP networks. In other words to find a method to make a non-linear and multivariable model that performs at least as good as a linear model, when the training data lacks information....

  20. Combined trabeculectomy and cataract extraction-A retrospective study

    Directory of Open Access Journals (Sweden)

    Prasad V

    1988-01-01

    Full Text Available Ninety six eyes haying senile cataract and as-sociated open-angle glaucoma had been operated upon over a period of seven years by a combined procedure. The advantages of combined opera-tion have been discussed. The results were en-couraging.

  1. COMBINATION OF MORPHINE AND GABAPENTIN LEADS TO SYNERGISTIC EFFECTS IN A RAT MODEL OF POSTOPERATIVE PAIN

    DEFF Research Database (Denmark)

    Papathanasiou, Theodoros; Juul, Rasmus Vestergaard; Heegaard, Anne-Marie

    Postoperative pain is a complex clinical condition that is still inadequately managed. Opioids remain the first line agents for the management of postoperative pain despite their side effects. Combination treatment with non-opioid agents that act at different sites within the central and peripheral...... nervous system might lead to synergistic effects, thus minimizing the necessary morphine dose and correspondingly its side effects. In a blinded, randomized, 16 arms study, the pharmacodynamic interactions of morphine and gabapentin were evaluated. In the plantar incision model in the rat, a series...... and minimize side effects of morphine....

  2. Forecasting and Analysis of Agricultural Product Logistics Demand in Tibet Based on Combination Forecasting Model

    Institute of Scientific and Technical Information of China (English)

    Wenfeng; YANG

    2015-01-01

    Over the years,the logistics development in Tibet has fallen behind the transport. Since the opening of Qinghai-Tibet Railway in2006,the opportunity for development of modern logistics has been brought to Tibet. The logistics demand analysis and forecasting is a prerequisite for regional logistics planning. By establishing indicator system for logistics demand of agricultural products,agricultural product logistics principal component regression model,gray forecasting model,BP neural network forecasting model are built. Because of the single model’s limitations,quadratic-linear programming model is used to build combination forecasting model to predict the logistics demand scale of agricultural products in Tibet over the next five years. The empirical analysis results show that combination forecasting model is superior to single forecasting model,and it has higher precision,so combination forecasting model will have much wider application foreground and development potential in the field of logistics.

  3. A combined model of human erythropoiesis and granulopoiesis under growth factor and chemotherapy treatment.

    Science.gov (United States)

    Schirm, Sibylle; Engel, Christoph; Loeffler, Markus; Scholz, Markus

    2014-05-26

    Haematotoxicity of conventional chemotherapies often results in delays of treatment or reduction of chemotherapy dose. To ameliorate these side-effects, patients are routinely treated with blood transfusions or haematopoietic growth factors such as erythropoietin (EPO) or granulocyte colony-stimulating factor (G-CSF). For the latter ones, pharmaceutical derivatives are available, which differ in absorption kinetics, pharmacokinetic and -dynamic properties. Due to the complex interaction of cytotoxic effects of chemotherapy and the stimulating effects of different growth factor derivatives, optimal treatment is a non-trivial task. In the past, we developed mathematical models of thrombopoiesis, granulopoiesis and erythropoiesis under chemotherapy and growth-factor applications which can be used to perform clinically relevant predictions regarding the feasibility of chemotherapy schedules and cytopenia prophylaxis with haematopoietic growth factors. However, interactions of lineages and growth-factors were ignored so far. To close this gap, we constructed a hybrid model of human granulopoiesis and erythropoiesis under conventional chemotherapy, G-CSF and EPO applications. This was achieved by combining our single lineage models of human erythropoiesis and granulopoiesis with a common stem cell model. G-CSF effects on erythropoiesis were also implemented. Pharmacodynamic models are based on ordinary differential equations describing proliferation and maturation of haematopoietic cells. The system is regulated by feedback loops partly mediated by endogenous and exogenous EPO and G-CSF. Chemotherapy is modelled by depletion of cells. Unknown model parameters were determined by fitting the model predictions to time series data of blood counts and cytokine profiles. Data were extracted from literature or received from cooperating clinical study groups. Our model explains dynamics of mature blood cells and cytokines after growth-factor applications in healthy volunteers

  4. PAH exposure through soil ingestion: Combining digestion models and bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Wiele, T.R. van de; Verstraete, W. [Ghent University (BE).Laboratory Microbial Ecology and Technology (LabMET); Siciliano, S.D. [University of Saskatchewan (Canada). Department of Soil Science

    2003-07-01

    Exposure to environmental contaminants through soil ingestion is an important issue in current health risk assessment. Polycyclic aromatic hydrocarbons (PAH) or their metabolites pose risks to humans due to their toxic, mutagenic, carcinogenic or even (anti)estrogenic properties. PAH mobilization from a soil matrix (49.1{+-}1.5 mg PAH/kg DW) was assessed using a Simulator of the Human Intestinal Microbial Ecosystem (SHIME). PAH GC-MS analysis was performed on the pellet and supernatant of SHIME digests and gave 101, 92, 89 and 97% recovery for water, stomach, duodenal and colon digests, respectively. PAH release was highest for the water extract (0.51%) and the stomach digestion (0.44%). Lower mobilized fractions in the duodenum (0.13%) and colon (0.30%) digests could be attributed to PAH complexation with bile salts, dissolved organic matter or colon microbiota. The digestion model provides us with relevant information to what extent soil bound PAHs are mobilized in the gastrointestinal tract and thus reach the gut wall, prior to absorption. (orig.)

  5. A particulate model of solid waste incineration in a fluidized bed combining combustion and heavy metal vaporization

    Energy Technology Data Exchange (ETDEWEB)

    Mazza, G. [Facultad de Ingenieria, Departamento de Quimica, Universidad Nacional del Comahue, UE Neuquen (CONICET - UNCo), Buenos Aires 1400, 8300 Neuquen (Argentina); Falcoz, Q.; Gauthier, D.; Flamant, G. [Laboratoire Procedes Materiaux et Energie Solaire (CNRS-PROMES), 7 Rue du Four Solaire, Odeillo, 66120 Font-Romeu (France)

    2009-11-15

    This study aims to develop a particulate model combining solid waste particle combustion and heavy metal vaporization from burning particles during MSW incineration in a fluidized bed. The original approach for this model combines an asymptotic combustion model for the carbonaceous solid combustion and a shrinking core model to describe the heavy metal vaporization. A parametric study is presented. The global metal vaporization process is strongly influenced by temperature. Internal mass transfer controls the metal vaporization rate at low temperatures. At high temperatures, the chemical reactions associated with particle combustion control the metal vaporization rate. A comparison between the simulation results and experimental data obtained with a laboratory-scale fluid bed incinerator and Cd-spiked particles shows that the heavy metal vaporization is correctly predicted by the model. The predictions are better at higher temperatures because of the temperature gradient inside the particle. Future development of the model will take this into account. (author)

  6. Anaerobic Digestion and Combined Heat and Power Study

    Energy Technology Data Exchange (ETDEWEB)

    Frank J. Hartz

    2011-12-30

    One of the underlying objectives of this study is to recover the untapped energy in wastewater biomass. Some national statistics worth considering include: (1) 5% of the electrical energy demand in the US is used to treat municipal wastewater; (2) This carbon rich wastewater is an untapped energy resource; (3) Only 10% of wastewater treatment plants (>5mgd) recover energy; (4) Wastewater treatment plants have the potential to produce > 575 MW of energy nationwide; and (5) Wastewater treatment plants have the potential to capture an additional 175 MW of energy from waste Fats, Oils and Grease. The WSSC conducted this study to determine the feasibility of utilizing anaerobic digestion and combined heat and power (AD/CHP) and/or biosolids gasification and drying facilities to produce and utilize renewable digester biogas. Digester gas is considered a renewable energy source and can be used in place of fossil fuels to reduce greenhouse gas emissions. The project focus includes: (1) Converting wastewater Biomass to Electricity; (2) Using innovative technologies to Maximize Energy Recovery; and (3) Enhancing the Environment by reducing nutrient load to waterways (Chesapeake Bay), Sanitary Sewer Overflows (by reducing FOG in sewers) and Greenhouse Gas Emissions. The study consisted of these four tasks: (1) Technology screening and alternative shortlisting, answering the question 'what are the most viable and cost effective technical approaches by which to recover and reuse energy from biosolids while reducing disposal volume?'; (2) Energy recovery and disposal reduction potential verification, answering the question 'how much energy can be recovered from biosolids?'; (3) Economic environmental and community benefit analysis, answering the question 'what are the potential economic, environmental and community benefits/impacts of each approach?'; and (4) Recommend the best plan and develop a concept design.

  7. A large scale hydrological model combining Budyko hypothesis and stochastic soil moisture model

    Science.gov (United States)

    Cong, Z.; Zhang, X.

    2012-04-01

    Based on the Budyko hypothesis, the actual evapotranspiration, E,is controlled by the water conditions and the energy conditions, which are represented by the amount of annual precipitation, P and potential evaporation, E0, respectively. Some theoretical or empirical equations have been proposed to represent the Budyko curve. We here select Choudhury's equation to describe the Budyko curve (Mezentsev, 1954; Choudhury, 1999; Yang et al., 2008; Roderick and Farquhar, 2011). ɛ = (1+ φ -α)-1/α ,ɛ = E-,φ = E0 P P Rodriguez-Iturbe et al. (1999) proposed a stochastic soil moisture model based on a Poisson distributed rainfall assumption. Porporato et al. (2004) described the average water balance based on stochastic soil moisture model as following, γ- 1 ɛ = 1 -φ(·γ)φ--(·e-γ),γ = Zr- Γ γ- - Γ γ-,γ h φ φ where, h means the average rainfall depth, Zr means basin water storage ability. Combining these two equation, we can get the relation between α and γ. Then we develop a large scale hydrological model to estimate annual runoff from P, E0, h and Zr. ( -α)- 1/α 0.5946 Zr- R = (1- ɛ)P,ɛ = 1+ φ ,a = 0.7078γ ,γ = h This method has good performance when it is applied to estimate annual runoff in the Yellow River Basin and the Yangtze River Basin. The impacts of climate changes (P, E0 and h) and human activities (Zr) are also discussed with this method.

  8. Clinicopathological studies on three preoperative combined treatments for rectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yoshioka, Yuji; Ichikawa, Daisuke; Iizuka, Ryouji; Hagiwara, Akeo; Sawai, Kiyoshi; Yamaguchi, Toshiharu; Takahashi, Toshio [Kyoto Prefectural Univ. of Medicine (Japan)

    1995-09-01

    To prevent postoperative local recurrence of rectal cancer, we treated patients using preoperative hyperthermia (5-6 times), irradiation (total 30 Gy) and 5-fluorouracil suppository (2,000-2,500 mg). The subjects were 31 patients given combined treatments and 28 patients given surgery alone. The results were as follows: Histologically, therapeutic effects were recognized in 80.6% of patients receiving combined treatments. The mean distance from the adventitia to the site of cancer infiltration was 6.54 mm in the combined treatments group and 3.35 mm in the surgery alone group. The difference between the two was significant (p<0.05). The rate of local recurrence in the combined treatments group was less than that in the surgery alone group. No systemic side effects nor severe complications were observed during hospitalization in the combined treatments group. The survival rate of the combined treatments group was higher than that of the surgery alone group. It was considered that combined preoperative treatments for rectal cancer were beneficial to survival and local control. (author).

  9. Efficient pan-European flood hazard modelling through a combination of statistical and physical models

    Science.gov (United States)

    Paprotny, Dominik; Morales Nápoles, Oswaldo

    2016-04-01

    Low-resolution hydrological models are often applied to calculate extreme river discharges and delimitate flood zones on continental and global scale. Still, the computational expense is very large and often limits the extent and depth of such studies. Here, we present a quick yet similarly accurate procedure for flood hazard assessment in Europe. Firstly, a statistical model based on Bayesian Networks is used. It describes the joint distribution of annual maxima of daily discharges of European rivers with variables describing the geographical characteristics of their catchments. It was quantified with 75,000 station-years of river discharge, as well as climate, terrain and land use data. The model's predictions of average annual maxima or discharges with certain return periods are of similar performance to physical rainfall-runoff models applied at continental scale. A database of discharge scenarios - return periods under present and future climate - was prepared for the majority of European rivers. Secondly, those scenarios were used as boundary conditions for one-dimensional (1D) hydrodynamic model SOBEK. Utilizing 1D instead of 2D modelling conserved computational time, yet gave satisfactory results. The resulting pan-European flood map was contrasted with some local high-resolution studies. Indeed, the comparison shows that, in overall, the methods presented here gave similar or better alignment with local studies than previously released pan-European flood map.

  10. Optical, size and mass properties of mixed type aerosols in Greece and Romania as observed by synergy of lidar and sunphotometers in combination with model simulations: a case study.

    Science.gov (United States)

    Papayannis, A; Nicolae, D; Kokkalis, P; Binietoglou, I; Talianu, C; Belegante, L; Tsaknakis, G; Cazacu, M M; Vetres, I; Ilic, L

    2014-12-01

    A coordinated experimental campaign aiming to study the aerosol optical, size and mass properties was organized in September 2012, in selected sites in Greece and Romania. It was based on the synergy of lidar and sunphotometers. In this paper we focus on a specific campaign period (23-24 September), where mixed type aerosols (Saharan dust, biomass burning and continental) were confined from the Planetary Boundary Layer (PBL) up to 4-4.5 km height. Hourly mean linear depolarization and lidar ratio values were measured inside the dust layers, ranging from 13 to 29 and from 44 to 65sr, respectively, depending on their mixing status and the corresponding air mass pathways over Greece and Romania. During this event the columnar Aerosol Optical Depth (AOD) values ranged from 0.13 to 0.26 at 532 nm. The Lidar/Radiometer Inversion Code (LIRIC) and the Polarization Lidar Photometer Networking (POLIPHON) codes were used and inter-compared with regards to the retrieved aerosol (fine and coarse spherical/spheroid) mass concentrations, showing that LIRIC generally overestimates the aerosol mass concentrations, in the case of spherical particles. For non-spherical particles the difference in the retrieved mass concentration profiles from these two codes remained smaller than ±20%. POLIPHON retrievals showed that the non-spherical particles reached concentrations of the order of 100-140 μg/m(3) over Romania compared to 50-75 μg/m(3) over Greece. Finally, the Dust Regional Atmospheric Model (DREAM) model was used to simulate the dust concentrations over the South-Eastern Europe.

  11. Computing the modal mass from the state space model in combined experimental-operational modal analysis

    Science.gov (United States)

    Cara, Javier

    2016-05-01

    Modal parameters comprise natural frequencies, damping ratios, modal vectors and modal masses. In a theoretic framework, these parameters are the basis for the solution of vibration problems using the theory of modal superposition. In practice, they can be computed from input-output vibration data: the usual procedure is to estimate a mathematical model from the data and then to compute the modal parameters from the estimated model. The most popular models for input-output data are based on the frequency response function, but in recent years the state space model in the time domain has become popular among researchers and practitioners of modal analysis with experimental data. In this work, the equations to compute the modal parameters from the state space model when input and output data are available (like in combined experimental-operational modal analysis) are derived in detail using invariants of the state space model: the equations needed to compute natural frequencies, damping ratios and modal vectors are well known in the operational modal analysis framework, but the equation needed to compute the modal masses has not generated much interest in technical literature. These equations are applied to both a numerical simulation and an experimental study in the last part of the work.

  12. Evaluation of the transdermal permeation of different paraben combinations through a pig ear skin model.

    Science.gov (United States)

    Caon, Thiago; Costa, Ana Carolina Oliveira; de Oliveira, Marcone Augusto Leal; Micke, Gustavo Amadeu; Simões, Cláudia Maria Oliveira

    2010-05-31

    Although parabens have several features of ideal preservatives, different studies have shown that they may affect human health due to their estrogenic activity. Therefore, various strategies have been applied to reduce their skin penetration. However, the effect of paraben combinations on transdermal permeation has not yet been investigated. Thus, the objective of this study was to evaluate paraben permeation in pig ear skin using a Franz diffusion cell system with capillary electrophoresis detection, in order to identify which paraben combinations (defined by a factorial design) have the lowest skin permeation. The permeation of isolated parabens was also evaluated and the permeation characteristics, obtained by the Moser model, confirmed that lipophilicity and molecular weight may influence the systemic absorption of these compounds. In previous tests using isolated parabens, methyl and ethyl parabens presented greater retention in the epidermis compared to the dermis, while propyl and butyl parabens had similar retention profiles in these layers. An increase in ethanol concentration and experimental time promoted greater parabens retention in the dermis compared to the epidermis. The binary combinations of methyl and ethyl parabens as well as of methyl and propyl parabens (added to several cosmetic products in order to increase the antimicrobial spectrum) reduced significantly their permeation rates through pig ear skin (with the exception of EP), probably due to the high retention of these parabens in the epidermis and dermis.

  13. Combining fisetin and ionizing radiation suppresses the growth of mammalian colorectal cancers in xenograft tumor models.

    Science.gov (United States)

    Leu, Jyh-Der; Wang, Bo-Shen; Chiu, Shu-Jun; Chang, Chun-Yuan; Chen, Chien-Chih; Chen, Fu-Du; Avirmed, Shiirevnyamba; Lee, Yi-Jang

    2016-12-01

    Fisetin (3,7,3',4'-tetrahydroxyflavone), which belongs to the flavonoid group of polyphenols and is found in a wide range of plants, has been reported to exhibit a number of biological activities in human cancer cells, including antioxidant, anti-inflammatory, antiangiogenic, anti-invasive and antiproliferative effects. Although previous in vitro studies have shown that fisetin treatment increases the apoptotic rate and enhances the radiosensitivity of human colorectal cancer cells, the in vivo effects of fisetin on tumor growth remain unclear. In the present study a murine xenograft tumor model was employed to investigate the therapeutic effects of fisetin in combination with radiation on CT-26 colon cancer cells and human HCT116 colorectal cancer cells. This revealed that intratumoral injection of fisetin significantly suppressed the growth of CT-26 tumors compared with the untreated control group, but had little effect on the growth of HCT116 tumors. However, fisetin in combination with 2-Gy radiation enhanced tumor suppressor activity in murine colon and human colorectal xenograft tumors, as compared with 2-Gy fractionated radiation administered alone for 5 days and fisetin alone. Interestingly, fisetin downregulated the expression of the oncoprotein securin in a p53-independent manner. However, securin-null HCT116 tumors showed only moderate sensitivity to fisetin treatment, and the combination of fisetin and radiation did not significantly suppress securin-null HCT116 tumor growth compared with normal HCT116 tumors. Therefore, the role of securin in mediating the effect of fisetin on colorectal cancer growth warrants further investigation. In conclusion, the results of the current study provide important preclinical data for evaluating the efficacy of fisetin and radiation combination treatment as an adjuvant chemoradiotherapy for human colorectal cancers.

  14. Nonlinear combined forecasting model based on fuzzy adaptive variable weight and its application

    Institute of Scientific and Technical Information of China (English)

    JIANG Ai-hua; MEI Chi; E Jia-qiang; SHI Zhang-ming

    2010-01-01

    In order to enhance forecasting precision of problems about nonlinear time series in a complex industry system,a new nonlinear fuzzy adaptive variable weight combined forecasting model was established by using conceptions of the relative error,the change tendency of the forecasted object,gray basic weight and adaptive control coefficient on the basis of the method of fuzzy variable weight.Based on Visual Basic 6.0 platform,a fuzzy adaptive variable weight combined forecasting and management system was developed.The application results reveal that the forecasting precisions from the new nonlinear combined forecasting model are higher than those of other single combined forecasting models and the combined forecasting and management system is very powerful tool for the required decision in complex industry system.

  15. An empirical movement model for sixgill sharks in Puget Sound: Combining observed and unobserved behavior

    Institute of Scientific and Technical Information of China (English)

    Phillip S. LEVIN; Peter HORNE; Kelly S. ANDREWS; Greg WILLIAMS

    2012-01-01

    Understanding the movement of animals is fundamental to population and community ecology.Historically,it has been difficult to quantify movement patterns of most fishes,but technological advances in acoustic telemetry have increased our abilities to monitor their movement.In this study,we combined small-scale active acoustic tracking with large-scale passive acoustic monitoring to develop an empirical movement model for sixgill sharks in Puget Sound,WA,USA.We began by testing whether a correlated random walk model described the daily movement of sixgills; however,the model failed to capture home-ranging behavior.We added this behavior and used the resultant model (a biased random walk model) to determine whether daily movement patterns are able to explain large-scale seasonal movement.The daily model did not explain the larger-scale patterns of movement observed in the passive monitoring data.In order to create the large-scale patterns,sixgills must have performed behaviors (large,fast directed movements) that were unobserved during small-scale active tracking.In addition,seasonal shifts in location were not captured by the daily model.We added these ‘unobserved' behaviors to the model and were able to capture large-scale seasonal movement of sixgill sharks over 150 days.The development of empirical models of movement allows researchers to develop hypotheses and test mechanisms responsible for a species movement behavior and spatial distribution.This knowledge will increase our ability to successfully manage species of concern [Current Zoology 58 (1):103-115,2012].

  16. Models of Hemodynamics and Hematopoiesis Following Hemorrhage for Use in Combined Injury Simulations

    Science.gov (United States)

    2016-06-01

    resulting from a nuclear detonation and will assist in medical planning . Hemorrhage, Combined Injury, Ordinary Differential Equation Model, Fluid...Computer models can help predict the resource requirements for attending to casualties and assist in medical planning . Model extensions described in this...first phase, involves the restitution of plasma proteins to support plasma oncotic pressure and continued blood volume expansion. While this increase

  17. ECONOMIC EVALUATION OF COMBINED THERAPY OF ARTERIAL HYPERTENSION BY MARKOV’S MODELING

    Directory of Open Access Journals (Sweden)

    N. S. Maksimchuk-Kolobova

    2015-09-01

    Full Text Available Aim. To evaluate the economic effectiveness of the combined two-drug antihypertensive therapy in patients with arterial hypertension (HT and high cardiovascular risk by Markov’s modeling.Material and methods. Patients (n= 65; 19 males and 46 females with essential HT accompanied by metabolic disorders, history of previous ineffective antihypertensive therapy were included into the study. Patients were randomized into 2 groups. Group V/A was treated with valsartan and amlodipine in fixed-dose combinations of 160/5 and 160/10 mg depending on blood pressure (BP level. Patients of group L/A were treated with losartan 100 mg and amlodipine 5 or 10 mg daily. Treatment duration was 24 weeks. Changes in BP level, and left ventricular hypertrophy (LVH regression were assessed. Economic evaluation was performed on the basis of modeling with specialized software Decision Tree 4.xla.Results. Effect of the two variants of combination therapy on LVH was used to estimate treatment effectiveness and to build the model. Patients were distributed according to the left ventricular mass (LVM at baseline and after 24 weeks of therapy. Significant decrease in LVM was observed in V/A group: from 225.1±71.7 to 186.3±44.5 g (p<0.05. There was no LVM dynamics in L/A group. The model took into account economic and frequency factors for 10 years forecast. V/A therapy is able to prevent 94 deaths, 22 strokes, and 64 myocardial infarction per 1000 patients. Absence of need in treatment of these prevented events can save about 5.5 million RUR for every 1000 patients. It would reduce the total costs per patient during 10 years. V/A therapy is able to save maximal number of quality adjusted life years (QALY due to LVM regression (5.016 years. L/A combination is the most economical variant of pharmacotherapy due to low cost of treatment (16.491.25 RUR per 1 QALY. It would take 286.698.7 RUR additionally for one additional QALY in the treatment with V/A, and it is

  18. Reporting guidelines for modelling studies

    Directory of Open Access Journals (Sweden)

    Bennett Carol

    2012-11-01

    Full Text Available Abstract Background Modelling studies are used widely to help inform decisions about health care and policy and their use is increasing. However, in order for modelling to gain strength as a tool for health policy, it is critical that key model factors are transparent so that users of models can have a clear understanding of the model and its limitations.Reporting guidelines are evidence-based tools that specify minimum criteria for authors to report their research such that readers can both critically appraise and interpret study findings. This study was conducted to determine whether there is an unmet need for population modelling reporting guidelines. Methods We conducted a review of the literature to identify: 1 guidance for reporting population modelling studies; and, 2 evidence on the quality of reporting of population modelling studies. Guidance for reporting was analysed using a thematic approach and the data was summarised as frequencies. Evidence on the quality of reporting was reviewed and summarized descriptively. Results There were no guidelines that specifically addressed the reporting of population modelling studies. We identified a number of reporting guidelines for economic evaluation studies, some of which had sections that were relevant population modelling studies. Amongst seven relevant records, we identified 69 quality criteria that have distinct reporting characteristics. We identified two papers that addressed reporting practices of modelling studies. Overall, with the exception of describing the data used for calibration, there was little consistency in reporting. Conclusions While numerous guidelines exist for developing and evaluating health technology assessment and economic evaluation models, which by extension could be applicable to population modelling studies, there is variation in their comprehensiveness and in the consistency of reporting these methods. Population modelling studies may be an area which would

  19. Statistical Combination of Several Important Standard Model Higgs Boson Search Channels.

    CERN Document Server

    The ATLAS collaboration

    2009-01-01

    In this note we describe statistical procedures for combination of results from independent searches for the Higgs boson. Here only the Standard Model Higgs is considered, although the methods can easily be extended to non-standard Higgs models as well as to other searches. The methods are applied to Monte Carlo studies of four important search channels: H to tau+ tau-, H to W+ W- to e-nu mu-nu, H to gamma gamma, and H to ZZ)(*) to 4 leptons. The statistical treatment relies on a large sample approximation that is expected to be valid for an integrated luminosity of at least 2 fb-1 . Results are presented for the expected statistical significance of discovery and expected exclusion limits.

  20. Combining search space partition and search Space partition and abstraction for LTL model checking

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The state space explosion problem is still the key obstacle for applying model checking to systems of industrial size.Abstraction-based methods have been particularly successful in this regard.This paper presents an approach based on refinement of search space partition and abstraction which combines these two techniques for reducing the complexity of model checking.The refinement depends on the representation of each portion of search space. Especially, search space can be refined stepwise to get a better reduction. As reported in the case study, the Integration of search space partition and abstraction improves the efficiencyof verification with respect to the requirement of memory and obtains significant advantage over the use of each of them in isolation.

  1. Towards a theory of regional diversification : Combining insights from Evolutionary Economic Geography and Transition Studies

    NARCIS (Netherlands)

    Boschma, R.A.; Coenen, Lars; Frenken, K.; Truffer, B.

    2017-01-01

    Towards a theory of regional diversification: combining insights from Evolutionary Economic Geography and Transition Studies. Regional Studies. This paper develops a theoretical framework of regional diversification by combining insights from Evolutionary Economic Geography and Transition Studies.

  2. Combined Prediction Model of Death Toll for Road Traffic Accidents Based on Independent and Dependent Variables

    Science.gov (United States)

    Zhong-xiang, Feng; Shi-sheng, Lu; Wei-hua, Zhang; Nan-nan, Zhang

    2014-01-01

    In order to build a combined model which can meet the variation rule of death toll data for road traffic accidents and can reflect the influence of multiple factors on traffic accidents and improve prediction accuracy for accidents, the Verhulst model was built based on the number of death tolls for road traffic accidents in China from 2002 to 2011; and car ownership, population, GDP, highway freight volume, highway passenger transportation volume, and highway mileage were chosen as the factors to build the death toll multivariate linear regression model. Then the two models were combined to be a combined prediction model which has weight coefficient. Shapley value method was applied to calculate the weight coefficient by assessing contributions. Finally, the combined model was used to recalculate the number of death tolls from 2002 to 2011, and the combined model was compared with the Verhulst and multivariate linear regression models. The results showed that the new model could not only characterize the death toll data characteristics but also quantify the degree of influence to the death toll by each influencing factor and had high accuracy as well as strong practicability. PMID:25610454

  3. Combined Prediction Model of Death Toll for Road Traffic Accidents Based on Independent and Dependent Variables

    Directory of Open Access Journals (Sweden)

    Feng Zhong-xiang

    2014-01-01

    Full Text Available In order to build a combined model which can meet the variation rule of death toll data for road traffic accidents and can reflect the influence of multiple factors on traffic accidents and improve prediction accuracy for accidents, the Verhulst model was built based on the number of death tolls for road traffic accidents in China from 2002 to 2011; and car ownership, population, GDP, highway freight volume, highway passenger transportation volume, and highway mileage were chosen as the factors to build the death toll multivariate linear regression model. Then the two models were combined to be a combined prediction model which has weight coefficient. Shapley value method was applied to calculate the weight coefficient by assessing contributions. Finally, the combined model was used to recalculate the number of death tolls from 2002 to 2011, and the combined model was compared with the Verhulst and multivariate linear regression models. The results showed that the new model could not only characterize the death toll data characteristics but also quantify the degree of influence to the death toll by each influencing factor and had high accuracy as well as strong practicability.

  4. Combined Thickness of the Modeled Saddle Mountains Basalt and Mabton Interbed Geomodel Units (smthk_f)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The smthk_f grid represents the modeled combined thickness of the Saddle Mountains Basalt and Mabton interbed geomodel units at a 500 foot resolution. It is one grid...

  5. Potential Benefits of Combining Anomaly Detection with View Planning for UAV Infrastructure Modeling

    National Research Council Canada - National Science Library

    R Abraham Martin; Landen Blackburn; Joshua Pulsipher; Kevin Franke; John D Hedengren

    2017-01-01

    This paper presents a novel method for UAV-based 3D modeling of large infrastructure objects, such as pipelines, canals and levees, that combines anomaly detection with automatic on-board 3D view planning...

  6. Clinical Study on Treatment of Depression with Combined Acupuncture & Medicine

    Institute of Scientific and Technical Information of China (English)

    XU Hong; WANG Qiao-chu; HAN Chou-ping

    2003-01-01

    Purpose To observe and compare the curative effects of combined acupuncture and medicine with simple herbal medicine on treatment of depression. Method Altogether 63 cases were enrolled according to the determination of internationally accepted self-evaluation depression scales (SDS), among them 33 cases were treated with combination of acupuncture and herbal medicine (acupuncture-medicine group) and the other 30 cases were in treated with herbal medicine alone (herbal medicine group) Results The total effective rate of acupuncture-medicine group was 90.9% and that of herbal group was 80.0%. And there was significant statistics difference between the curative effects of two groups (P <0.05) without obvious adverse reaction. Conclusion Combination of acupuncture and medicine has better effect in treating depression than herbal medicine group.

  7. Assessment of groundwater vulnerability using supervised committee to combine fuzzy logic models.

    Science.gov (United States)

    Nadiri, Ata Allah; Gharekhani, Maryam; Khatibi, Rahman; Moghaddam, Asghar Asghari

    2017-02-13

    Vulnerability indices of an aquifer assessed by different fuzzy logic (FL) models often give rise to differing values with no theoretical or empirical basis to establish a validated baseline or to develop a comparison basis between the modeling results and baselines, if any. Therefore, this research presents a supervised committee fuzzy logic (SCFL) method, which uses artificial neural networks to overarch and combine a selection of FL models. The indices are expressed by the widely used DRASTIC framework, which include geological, hydrological, and hydrogeological parameters often subject to uncertainty. DRASTIC indices represent collectively intrinsic (or natural) vulnerability and give a sense of contaminants, such as nitrate-N, percolating to aquifers from the surface. The study area is an aquifer in Ardabil plain, the province of Ardabil, northwest Iran. Improvements on vulnerability indices are achieved by FL techniques, which comprise Sugeno fuzzy logic (SFL), Mamdani fuzzy logic (MFL), and Larsen fuzzy logic (LFL). As the correlation between estimated DRASTIC vulnerability index values and nitrate-N values is as low as 0.4, it is improved significantly by FL models (SFL, MFL, and LFL), which perform in similar ways but have differences. Their synergy is exploited by SCFL and uses the FL modeling results "conditioned" by nitrate-N values to raise their correlation to higher than 0.9.

  8. Combining Interactive Infrastructure Modeling and Evolutionary Algorithm Optimization for Sustainable Water Resources Design

    Science.gov (United States)

    Smith, R.; Kasprzyk, J. R.; Zagona, E. A.

    2013-12-01

    Population growth and climate change, combined with difficulties in building new infrastructure, motivate portfolio-based solutions to ensuring sufficient water supply. Powerful simulation models with graphical user interfaces (GUI) are often used to evaluate infrastructure portfolios; these GUI based models require manual modification of the system parameters, such as reservoir operation rules, water transfer schemes, or system capacities. Multiobjective evolutionary algorithm (MOEA) based optimization can be employed to balance multiple objectives and automatically suggest designs for infrastructure systems, but MOEA based decision support typically uses a fixed problem formulation (i.e., a single set of objectives, decisions, and constraints). This presentation suggests a dynamic framework for linking GUI-based infrastructure models with MOEA search. The framework begins with an initial formulation which is solved using a MOEA. Then, stakeholders can interact with candidate solutions, viewing their properties in the GUI model. This is followed by changes in the formulation which represent users' evolving understanding of exigent system properties. Our case study is built using RiverWare, an object-oriented, data-centered model that facilitates the representation of a diverse array of water resources systems. Results suggest that assumptions within the initial MOEA search are violated after investigating tradeoffs and reveal how formulations should be modified to better capture stakeholders' preferences.

  9. Future daily PM10 concentrations prediction by combining regression models and feedforward backpropagation models with principle component analysis (PCA)

    Science.gov (United States)

    Ul-Saufie, Ahmad Zia; Yahaya, Ahmad Shukri; Ramli, Nor Azam; Rosaida, Norrimi; Hamid, Hazrul Abdul

    2013-10-01

    Future PM10 concentration prediction is very important because it can help local authorities to enact preventative measures to reduce the impact of air pollution. The aims of this study are to improve prediction of Multiple Linear Regression (MLR) and Feedforward backpropagation (FFBP) by combining them with principle component analysis for predicting future (next day, next two-day and next three-day) PM10 concentration in Negeri Sembilan, Malaysia. Annual hourly observations for PM10 in Negeri Sembilan, Malaysia from January 2003 to December 2010 were selected for predicting PM10 concentration level. Eighty percent of the monitoring records were used for training and twenty percent were used for validation of the models. Three accuracy measures - Prediction Accuracy (PA), Coefficient of Determination (R2) and Index of Agreement (IA), as well as two error measures - Normalized Absolute Error (NAE) and Root Mean Square Error (RMSE) were used to evaluate the performance of the models. Results show that PCA models combined with MLR and PCA with FFBP improved MLR and FFBP models for all three days in advance of predicting PM10 concentration, with reduced errors by as much as 18.1% (PCA-MLR) and 17.68% (PCA-FFBP) for next day, 19.2% (PCA-MLR) and 22.1% (PCA-FFBP) for next two-day and 18.7% (PCA-MLR) and 22.79% (PCA-FFBP) for next three-day predictions. Including PCA improved the accuracy of the models by as much as by 12.9% (PCA-MLR) and 13.3% (PCA-FFBP) for next day, 32.3% (PCA-MLR) and 14.7% (PCA-FFBP) for next two-day and 46.1% (PCA-MLR) and 19.3% (PCA-FFBP) for next three-day predictions.

  10. Study on Effects of Combined Organic Fertilizer Application in Rice-duck Integrated Farming Model%稻鸭共作模式有机肥组合施用效果研究

    Institute of Scientific and Technical Information of China (English)

    裴正峰; 丁朝芳; 向敏; 林胜

    2014-01-01

    Objective to explore the effects of combined organic fertilizer application in Rice-Duck Integrated Farming System (RDIFS),in order to solve the problems of reasonable combination and application rate of organic fertilizers. Methods adopt a randomized block design and test the effects of different organic fertiliz-er combination samples. Results By using 1000kg rice straw compost plus 50kg rapeseed cake plus 50kg chicken manure or 1200kg rice straw compost plus 200kg chicken manure in every 667m2 test plot,the or-ganic rice production can reach 380kg.Conclusion RDIFS,the application of organic fertilizer with reason-able combination ratio can reach ance the soil nutrient supply and maintain the soil fertility,but also im-prove the rice yield and optimize the rice economy. However,it has no significant effect on organic rice quality improvement.%目的:探索稻鸭共作模式下有机肥组合施用效果,解决有机肥合理搭配和施用量问题。方法:采用随机区组设计,对不同有机肥组合施用效果进行抽样检测。结果:供试田块每667m2施用水稻秸秆堆肥1000kg+菜籽饼50kg+鸡粪50kg或水稻秸秆堆肥1200kg+鸡粪200kg,可获得有机稻380kg以上的产量。结论:稻鸭共作模式下,施用合理组配的有机肥不仅能够平衡土壤养分供应,维持地力,而且能够优化水稻经济性状,提高水稻产量,但对有机稻米品质的提高没有明显作用。

  11. Modelling the interaction of aeolian and fluvial processes with a combined cellular model of sand dunes and river systems

    Science.gov (United States)

    Liu, Baoli; Coulthard, Tom J.

    2017-09-01

    Aeolian and fluvial processes are important agents for shaping the surface of the Earth, but are largely studied in isolation despite there being many locations where both processes are acting together and influencing each other. Using field data to investigate fluvial-aeolian interactions is, however, hampered by our short length of record and low temporal resolution of observations. Here we use numerical modelling to investigate, for the first time, the interplay between aeolian (sand dunes) and fluvial (river channel) processes. This modelling is carried out by combining two existing cellular models of aeolian and fluvial processes that requires considerable consideration of the different process representation and time stepping used. The result is a fully coupled (in time and space) sand dune - river model. Over a thousand-year simulation the model shows how the migration of sand dunes is readily blocked by rivers, yet aeolian processes can push the channel downwind. Over time cyclic channel avulsions develop indicating that aeolian action on fluvial systems may play an important part in governing avulsion frequency, and thus alluvial architecture.

  12. Study on Combined Method Based on 3-D ESPI

    Institute of Scientific and Technical Information of China (English)

    Sun Ping; Zhang Xi; Wang Haifeng

    2002-01-01

    The finite element method (FEM),whether the calculation is accurate or not,depends closely on object boundary condition.If the three dimensional displacement of the object obtained in experiment is regarded as its boundary condition,a new method combining the results of experiment and calculation,called combined method (CM),is formed.The combined method possess advantages of experiment and calculation.It can correct calculation and improve the accuracy of FEM.Accordingly it has more practicability.In this paper,the three dimensional displacement fields of a typical beam loaded at three points are tested by using 3-D electric speckle pattern interferometry (ESPI).Using the experimental results as boundary condition the whole three-dimensional displacement fields can be calculated by FEM.The beam′s three-dimensional displacement fields obtained by FEM agree very well with those obtained by experiment.This proves that the combined method is effective and practicable.

  13. Study on Dielectric Function Models for Surface Plasmon Resonance Structure

    Directory of Open Access Journals (Sweden)

    Peyman Jahanshahi

    2014-01-01

    Full Text Available The most common permittivity function models are compared and identifying the best model for further studies is desired. For this study, simulations using several different models and an analytical analysis on a practical surface Plasmon structure were done with an accuracy of ∼94.4% with respect to experimental data. Finite element method, combined with dielectric properties extracted from the Brendel-Bormann function model, was utilized, the latter being chosen from a comparative study on four available models.

  14. Research on Short-Term Wind Power Prediction Based on Combined Forecasting Models

    Directory of Open Access Journals (Sweden)

    Zhang Chi

    2016-01-01

    Full Text Available Short-Term wind power forecasting is crucial for power grid since the generated energy of wind farm fluctuates frequently. In this paper, a physical forecasting model based on NWP and a statistical forecasting model with optimized initial value in the method of BP neural network are presented. In order to make full use of the advantages of the models presented and overcome the limitation of the disadvantage, the equal weight model and the minimum variance model are established for wind power prediction. Simulation results show that the combination forecasting model is more precise than single forecasting model and the minimum variance combination model can dynamically adjust weight of each single method, restraining the forecasting error further.

  15. CFD study of dominant effect in combined DTHT by using hypothetical boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Nietiadi, Yohanes Setiawan; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of); Addad, Yacine [KUSTAR, Abu Dhabi (United Arab Emirates)

    2015-05-15

    KAIST MMR is a gas cooled fast reactor (GFR) using supercritical CO{sub 2} as a working fluid of reactor core and power cycle without intermediate heat exchanger which operates in higher pressure and higher temperature conditions compared to PWR. During a Loss of Coolant Accident (LOCA), MMR needs to relay on passive Decay Heat Removal (DHR) system by using natural circulation of gas since passive decay heat removal using conduction and radiation is not providing sufficient decay heat removal. Very limited researches were conducted in the regime where both occur at the same time and in the same order of magnitude. Numerical analysis is done with v''2-f turbulence model to predict the physical phenomena for the future experimental work. The effects of buoyancy and acceleration were studied with CFD for designed cases to distinguish the dominant effect in the combined DTHT regime. Numerical results of the v''2-f turbulence model show that the model can predict the buoyancy induced DTHT phenomenon even when the acceleration parameter is greater than buoyancy parameter but there is no data that shows that acceleration induced DTHT dominates the DTHT phenomena at this moment. More numerical results in the combined DTHT regime will be obtained and studied to provide clearer view on strongly heated turbulent flow and its heat transfer deteriorating mechanism. Adjustment for v''2-f turbulence model to correct the prediction of buoyancy effect will be studied in the near future.

  16. 高压氧联合药物治疗脑胶质瘤模型鼠效果研究%Study on the therapeutic effects of hyperbaric oxygen combined with drugs on glioma in model mice

    Institute of Scientific and Technical Information of China (English)

    陆朝晖; 刘兵; 马笑宇; 戴纯刚; 贾敬云; 谢涛; 芮琴; 王爱东; 兰青

    2015-01-01

    Objective To investigate the therapeutic effects of the chemotherapeutic drug ACNU combined with hyperbaric oxygen (HBO) in the treatment of transplantation tumor of glioma stem/progenitor cells SU3.Methods The SU3 cells were inoculated subcutaneously into general NC nude mice which were kept in an independent ventilated cages (IVC).Following the development of the tumor,the tumor-bearing mice were sacrificed,and tumor tissues were harvested,then,inoculated subcutaneously into transgenic green fluorescence protein (GFP) nude mice.On the third day,the animals were randomly divided into 4 groups:the HBO group (n =7),the ACNU + HBO group (n =7),the ACNU group (n =7) and the control group (n =12).The first 2 groups were placed in the HBO-IVC without specific pathogens and treated with HBO,1 session a day for a duration of 100 minutes.The animals in the second and third groups were administered with ACNU abdominally at a dosage of 30 mg/kg,once a week for a duration of 3 weeks.The tumor volume was measured with the vernier caliper and the body mass of tumor-bearing mice was weighed with the balance weight,once every 3 days.At the end of the experiment,some tissues were collected to perform RT-PCR detection,the remaining tissues were used for pathological sections.Results As compared with those of the control group,changes in the transplantation tumor mass of various groups were as follows:The tumor mass for the ACNU + HBO group was (2 252.86 ± 1 062.54) mg (P =0.006);the tumor mass for the ACNU group was (1 914.28 ±744.55) mg (P=0.002);that for the HBO group was (4 680.00 ±2 538.40) mg(P =0.925);and that for the control group was (4 760.83 ± 1 989.18) mg.Histopathological examination indicated that necrotic hemorrhage foci in tumor tissues could be frequently observed in the control group,and numerous neoformative vessels around the hemorrhagic site could also be found.Proliferation of vascular endothelial cells was quite active under microscopy

  17. Decomposing fear perception: A combination of psychophysics and neurometric modeling of fear perception.

    Science.gov (United States)

    Forscher, Emily C; Zheng, Yan; Ke, Zijun; Folstein, Jonathan; Li, Wen

    2016-10-01

    Emotion perception is known to involve multiple operations and waves of analysis, but specific nature of these processes remains poorly understood. Combining psychophysical testing and neurometric analysis of event-related potentials (ERPs) in a fear detection task with parametrically varied fear intensities (N=45), we sought to elucidate key processes in fear perception. Building on psychophysics marking fear perception thresholds, our neurometric model fitting identified several putative operations and stages: four key processes arose in sequence following face presentation - fear-neutral categorization (P1 at 100ms), fear detection (P300 at 320ms), valuation (early subcomponent of the late positive potential/LPP at 400-500ms) and conscious awareness (late subcomponent LPP at 500-600ms). Furthermore, within-subject brain-behavior association suggests that initial emotion categorization was mandatory and detached from behavior whereas valuation and conscious awareness directly impacted behavioral outcome (explaining 17% and 31% of the total variance, respectively). The current study thus reveals the chronometry of fear perception, ascribing psychological meaning to distinct underlying processes. The combination of early categorization and late valuation of fear reconciles conflicting (categorical versus dimensional) emotion accounts, lending support to a hybrid model. Importantly, future research could specifically interrogate these psychological processes in various behaviors and psychopathologies (e.g., anxiety and depression). Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Phenotype and genotype of deaf patients with combined genomic and mitochondrial inheritance models.

    Science.gov (United States)

    Huang, Shasha; Wang, Guojian; Jiang, Yi; Yuan, Yongyi; Han, Dongyi; Song, Yueshuai; Dai, Pu

    2013-11-01

    In most studies, sensorineural hearing loss is reported as a single-gene disease with autosomal dominant or autosomal recessive or with X-linked or maternal inheritance. It is uncommon that the hearing impairment is caused by a combined inheritance model including genomic and mitochondrial models. Here, we report six patients with sensorineural hearing loss caused by co-existing mutations in GJB2 or SLC26A4 and the mitochondrial gene. And there was no significant difference in hearing phenotypes between the six patients and the controls. The results indicate the complicated genetic etiology of, and may impact the diagnostic strategy for, hereditary hearing impairment. All patient siblings will carry mitochondrial DNA A1555G or C1494T mutations, and 25% of siblings may carry the same homozygous or compound heterozygote mutations in GJB2 or SLC26A4. Although this combined inheritance is not common in the Chinese deaf population (0.10%), our findings will have great impact in genetic counseling and risk prediction for deafness.

  19. Treatment Efficacy of NGF Nanoparticles Combining Neural Stem Cell Transplantation on Alzheimer's Disease Model Rats.

    Science.gov (United States)

    Chen, Yan; Pan, Cuihuan; Xuan, Aiguo; Xu, Liping; Bao, Guoqing; Liu, Feiei; Fang, Jie; Long, Dahong

    2015-11-21

    Alzheimer's disease (AD) is the most common type of dementia. It causes progressive brain disorder involving loss of normal memory and thinking skills. The transplantation of neural stem cells (NSCs) has been reported to improve learning and memory function of AD rats, and protects basal forebrain cholinergic neurons. Nerve growth factor - poly (ethylene glycol) - poly (lactic-co-glycolic acid)-nanoparticles (NGF-PEG-PLGA-NPs) can facilitate the differentiation of NSCs in vitro. This study thus investigated the treatment efficacy of NGF-PEG-PLGA-NPs combining NSC transplantation in AD model rats. AD rats were prepared by injection of 192IgG-saporin into their lateral ventricles. Embryonic rat NSCs were separated, induced by NGF-PEG-PLGA-NPs in vitro, and were transplanted. The Morris water-maze test was used to evaluate learning and memory function, followed by immunohistochemical staining for basal forebrain cholinergic neurons, hippocampal synaptophysin, and acetylcholine esterase (AchE) fibers. Rats in the combined treatment group had significantly improved spatial learning ability compared to AD model animals (pAlzheimer's disease.

  20. Corticomuscular Activity Modeling by Combining Partial Least Squares and Canonical Correlation Analysis

    Directory of Open Access Journals (Sweden)

    Xun Chen

    2013-01-01

    Full Text Available Corticomuscular activity modeling based on multiple data sets such as electroencephalography (EEG and electromyography (EMG signals provides a useful tool for understanding human motor control systems. In this paper, we propose modeling corticomuscular activity by combining partial least squares (PLS and canonical correlation analysis (CCA. The proposed method takes advantage of both PLS and CCA to ensure that the extracted components are maximally correlated across two data sets and meanwhile can well explain the information within each data set. This complementary combination generalizes the statistical assumptions beyond both PLS and CCA methods. Simulations were performed to illustrate the performance of the proposed method. We also applied the proposed method to concurrent EEG and EMG data collected in a Parkinson’s disease (PD study. The results reveal several highly correlated temporal patterns between EEG and EMG signals and indicate meaningful corresponding spatial activation patterns. In PD subjects, enhanced connections between occipital region and other regions are noted, which is consistent with previous medical knowledge. The proposed framework is a promising technique for performing multisubject and bimodal data analysis.

  1. Combining neuroprotectants in a model of retinal degeneration: no additive benefit.

    Directory of Open Access Journals (Sweden)

    Fabiana Di Marco

    Full Text Available The central nervous system undergoing degeneration can be stabilized, and in some models can be restored to function, by neuroprotective treatments. Photobiomodulation (PBM and dietary saffron are distinctive as neuroprotectants in that they upregulate protective mechanisms, without causing measurable tissue damage. This study reports a first attempt to combine the actions of PBM and saffron. Our working hypothesis was that the actions of PBM and saffron in protecting retinal photoreceptors, in a rat light damage model, would be additive. Results confirmed the neuroprotective potential of each used separately, but gave no evidence that their effects are additive. Detailed analysis suggests that there is actually a negative interaction between PBM and saffron when given simultaneously, with a consequent reduction of the neuroprotection. Specific testing will be required to understand the mechanisms involved and to establish whether there is clinical potential in combining neuroprotectants, to improve the quality of life of people affected by retinal pathology, such as age-related macular degeneration, the major cause of blindness and visual impairment in older adults.

  2. Combining operational models and data into a dynamic vessel risk assessment tool for coastal regions

    Science.gov (United States)

    Fernandes, R.; Braunschweig, F.; Lourenço, F.; Neves, R.

    2016-02-01

    The technological evolution in terms of computational capacity, data acquisition systems, numerical modelling and operational oceanography is supplying opportunities for designing and building holistic approaches and complex tools for newer and more efficient management (planning, prevention and response) of coastal water pollution risk events. A combined methodology to dynamically estimate time and space variable individual vessel accident risk levels and shoreline contamination risk from ships has been developed, integrating numerical metocean forecasts and oil spill simulations with vessel tracking automatic identification systems (AIS). The risk rating combines the likelihood of an oil spill occurring from a vessel navigating in a study area - the Portuguese continental shelf - with the assessed consequences to the shoreline. The spill likelihood is based on dynamic marine weather conditions and statistical information from previous accidents. The shoreline consequences reflect the virtual spilled oil amount reaching shoreline and its environmental and socio-economic vulnerabilities. The oil reaching shoreline is quantified with an oil spill fate and behaviour model running multiple virtual spills from vessels along time, or as an alternative, a correction factor based on vessel distance from coast. Shoreline risks can be computed in real time or from previously obtained data. Results show the ability of the proposed methodology to estimate the risk properly sensitive to dynamic metocean conditions and to oil transport behaviour. The integration of meteo-oceanic + oil spill models with coastal vulnerability and AIS data in the quantification of risk enhances the maritime situational awareness and the decision support model, providing a more realistic approach in the assessment of shoreline impacts. The risk assessment from historical data can help finding typical risk patterns ("hot spots") or developing sensitivity analysis to specific conditions, whereas real

  3. Combining operational models and data into a dynamic vessel risk assessment tool for coastal regions

    Directory of Open Access Journals (Sweden)

    R. Fernandes

    2015-07-01

    Full Text Available The technological evolution in terms of computational capacity, data acquisition systems, numerical modelling and operational oceanography is supplying opportunities for designing and building holistic approaches and complex tools for newer and more efficient management (planning, prevention and response of coastal water pollution risk events. A combined methodology to dynamically estimate time and space variable shoreline risk levels from ships has been developed, integrating numerical metocean forecasts and oil spill simulations with vessel tracking automatic identification systems (AIS. The risk rating combines the likelihood of an oil spill occurring from a vessel navigating in a study area – Portuguese Continental shelf – with the assessed consequences to the shoreline. The spill likelihood is based on dynamic marine weather conditions and statistical information from previous accidents. The shoreline consequences reflect the virtual spilled oil amount reaching shoreline and its environmental and socio-economic vulnerabilities. The oil reaching shoreline is quantified with an oil spill fate and behaviour model running multiple virtual spills from vessels along time. Shoreline risks can be computed in real-time or from previously obtained data. Results show the ability of the proposed methodology to estimate the risk properly sensitive to dynamic metocean conditions and to oil transport behaviour. The integration of meteo-oceanic + oil spill models with coastal vulnerability and AIS data in the quantification of risk enhances the maritime situational awareness and the decision support model, providing a more realistic approach in the assessment of shoreline impacts. The risk assessment from historical data can help finding typical risk patterns, "hot spots" or developing sensitivity analysis to specific conditions, whereas real time risk levels can be used in the prioritization of individual ships, geographical areas, strategic tug

  4. A Combined Cooperative Braking Model with a Predictive Control Strategy in an Electric Vehicle

    Directory of Open Access Journals (Sweden)

    Hongqiang Guo

    2013-12-01

    Full Text Available Cooperative braking with regenerative braking and mechanical braking plays an important role in electric vehicles for energy-saving control. Based on the parallel and the series cooperative braking models, a combined model with a predictive control strategy to get a better cooperative braking performance is presented. The balance problem between the maximum regenerative energy recovery efficiency and the optimum braking stability is solved through an off-line process optimization stream with the collaborative optimization algorithm (CO. To carry out the process optimization stream, the optimal Latin hypercube design (Opt LHD is presented to discrete the continuous design space. To solve the poor real-time problem of the optimization, a high-precision predictive model based on the off-line optimization data of the combined model is built, and a predictive control strategy is proposed and verified through simulation. The simulation results demonstrate that the predictive control strategy and the combined model are reasonable and effective.

  5. Combined Effects of Lipophilic Phycotoxins (Okadaic Acid, Azapsiracid-1 and Yessotoxin on Human Intestinal Cells Models

    Directory of Open Access Journals (Sweden)

    Pierre-Jean Ferron

    2016-02-01

    Full Text Available Phycotoxins are monitored in seafood because they can cause food poisonings in humans. Phycotoxins do not only occur singly but also as mixtures in shellfish. The aim of this study was to evaluate the in vitro toxic interactions of binary combinations of three lipophilic phycotoxins commonly found in Europe (okadaic acid (OA, yessotoxin (YTX and azaspiracid-1 (AZA-1 using the neutral red uptake assay on two human intestinal cell models, Caco-2 and the human intestinal epithelial crypt-like cells (HIEC. Based on the cytotoxicity of individual toxins, we studied the interactions between toxins in binary mixtures using the combination index-isobologram equation, a method widely used in pharmacology to study drug interactions. This method quantitatively classifies interactions between toxins in mixtures as synergistic, additive or antagonistic. AZA-1/OA, and YTX/OA mixtures showed increasing antagonism with increasing toxin concentrations. In contrast, the AZA-1/YTX mixture showed increasing synergism with increasing concentrations, especially for mixtures with high YTX concentrations. These results highlight the hazard potency of AZA-1/YTX mixtures with regard to seafood intoxication.

  6. Epidural ropivacaine combined with fentanyl or in combination with clonidine in infraumblical surgeries: a comparative study

    Directory of Open Access Journals (Sweden)

    Rakesh Bahadur Singh

    2015-10-01

    Conclusions: So this study re-established the fact, that the fentanyl and clonidine when added as adjuvant to epidural ropivacaine, significantly prolongs the analgesic duration without causing significant hemodynamic and respiratory changes. [Int J Res Med Sci 2015; 3(10.000: 2740-2744

  7. Combining a Detailed Building Energy Model with a Physically-Based Urban Canopy Model

    Science.gov (United States)

    Bueno, Bruno; Norford, Leslie; Pigeon, Grégoire; Britter, Rex

    2011-09-01

    A scheme that couples a detailed building energy model, EnergyPlus, and an urban canopy model, the Town Energy Balance (TEB), is presented. Both models are well accepted and evaluated within their individual scientific communities. The coupled scheme proposes a more realistic representation of buildings and heating, ventilation and air-conditioning (HVAC) systems, which allows a broader analysis of the two-way interactions between the energy performance of buildings and the urban climate around the buildings. The scheme can be used to evaluate the building energy models that are being developed within the urban climate community. In this study, the coupled scheme is evaluated using measurements conducted over the dense urban centre of Toulouse, France. The comparison includes electricity and natural gas energy consumption of buildings, building façade temperatures, and urban canyon air temperatures. The coupled scheme is then used to analyze the effect of different building and HVAC system configurations on building energy consumption, waste heat released from HVAC systems, and outdoor air temperatures for the case study of Toulouse. Three different energy efficiency strategies are analyzed: shading devices, economizers, and heat recovery.

  8. Non-linear absorption of 1.3-μm wavelength femtosecond laser pulses focused inside semiconductors: Finite difference time domain-two temperature model combined computational study

    Science.gov (United States)

    Bogatyrev, I. B.; Grojo, D.; Delaporte, P.; Leyder, S.; Sentis, M.; Marine, W.; Itina, T. E.

    2011-11-01

    We present a theoretical model, which describes local energy deposition inside IR-transparent silicon and gallium arsenide with focused 1.3-μm wavelength femtosecond laser pulses. Our work relies on the ionization rate equation and two temperature model (TTM), as we simulate the non-linear propagation of focused femtosecond light pulses by using a 3D finite difference time domain method. We find a strong absorption dependence on the initial free electron density (doping concentration) that evidences the role of avalanche ionization. Despite an influence of Kerr-type self-focusing at intensity required for non-linear absorption, we show the laser energy deposition remains confined when the focus position is moved down to 1-mm below the surface. Our simulation results are in agreement with the degree of control observed in a simple model experiment.

  9. Combining modelled and remote sensing soil moisture anomalies for an operational global drought monitoring

    Science.gov (United States)

    Cammalleri, Carmelo; Vogt, Jürgen

    2017-04-01

    Soil moisture anomalies (i.e., deviations from the climatology) are often seen as a reliable tool to monitor and quantify the occurrence of drought events and their potential impacts, especially in agricultural and naturally vegetated lands. Soil moisture datasets (or their proxy) can be derived from a variety of sources, including land-surface models and thermal and microwave satellite remote sensing images. However, each data source has different advantages and drawbacks that prevent to unequivocally prefer one dataset over the others, especially in global applications that encompass a wide range of soil moisture regimes. The analysis of the spatial reliability of the different datasets at global scale is further complicated by the lack of reliable long-term soil moisture records for a ground validation over most regions. To overcome this limitation, in recent years the Triple Collocation (TC) technique has been deployed in order to quantify the likely errors associated to three mutually-independent datasets without assuming that one of them represents the "truth". In this study, three global datasets of soil moisture anomalies are investigated: the first one derived from the runs of the Lisflood hydrological model, the second one obtained from the combined active/passive microwave dataset produced in the framework of the European Space Agency (ESA) Climate Change Initiative (CCI), and the last one derived from the Moderate-Resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST) observations. A preliminary analysis of the three datasets aimed at detecting the areas where the TC technique can be successfully applied, hence the spatial distribution of the random error variance for each model is evaluated. This study allows providing useful advises for a robust combination of the three datasets into a single product for a more reliable global drought monitoring.

  10. Synthesis and combinational antibacterial study of 5''-modified neomycin.

    Science.gov (United States)

    Zhang, Jianjun; Keller, Katherine; Takemoto, Jon Y; Bensaci, Mekki; Litke, Anthony; Czyryca, Przemyslaw Greg; Chang, Cheng-Wei Tom

    2009-10-01

    A library of 5''-modified neomycin derivatives were synthesized for an antibacterial structure-activity optimization strategy. Two leads exhibited prominent activity against both methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Antibacterial activities were measured when combined with other clinically used antibiotics. Significant synergistic activities were observed, which may lead to the development of novel therapeutic practices in the battle against infectious bacteria.

  11. Esophageal combined carcinomas: Immunohoistochemical and molecular genetic studies

    Institute of Scientific and Technical Information of China (English)

    Tadashi Terada; Hirotoshi Maruo

    2012-01-01

    Primary esophageal combined carcinoma is very rare.The authors herein report 2 cases.Case 1 was a combined squamous cell carcinoma and small cell carcinoma,and case 2 was a combined squamous cell carcinoma,adenocarcinoma,and small cell carcinoma.Case 1 was a 67-year-old man with complaints of dysphagia.Endoscopic examination revealed an ulcerated tumor in the middle esophagus,and 6 biopsies were obtained.All 6 biopsies revealed a mixture of squamous cell carcinoma and small cell carcinoma.Both elements were positive for cytokeratin,epithelial membrane antigen,and p53 protein,and had high Ki-67 labeling.The small cell carcinoma element was positive for synaptophysin,CD56,KIT,and platelet-derived growth factor-α (PDG-FRA),while the squamous cell carcinoma element was not.Genetically,no mutations of KIT and PDGFRA were recognized.The patient died of systemic carcinomatosis 15 mo after presentation.Case 2 was a 74-year-old man presenting with dysplasia.Endoscopy revealed a polypoid tumor in the distal esophagus.Seven biopsies were taken,and 6 showed a mixture of squamous cell carcinoma,small cell carcinoma,and adenocarcinoma.The 3 elements were positive for cytokeratins,epithelial membrane antigen,and p53 protein,and had high Ki-67 labeling.The adenocarcinoma element was positive for mucins.The small cell carcinoma element was positive for CD56,synaptophysin,KIT,and PDGFRA,but the other elements were not.Mutations of KIT and PDGFRA were not recognized.The patient died of systemic carcinomatosis 7 mo after presentation.These combined carcinomas may arise from enterochromaffin cells or totipotential stem cell in the esophagus or transdifferentiation of one element to another.A review of the literature was performed.

  12. Combined Ultrasound Imaging and Biomechanical Modeling to Estimate Triceps Brachii Musculotendon Changes in Stroke Survivors

    Directory of Open Access Journals (Sweden)

    Le Li

    2016-01-01

    Full Text Available The aim of this study was to investigate the changes of musculotendon parameters of triceps brachii in persons after stroke based on subject-specific biomechanical modeling technique combined with in vivo ultrasound measurement. Five chronic stroke survivors and five normal control subjects were recruited. B-mode ultrasound was applied to measure muscle pennation angle and the optimal length of three heads of triceps’ brachii at different joint angle positions in resting and isometric contraction. Measured ultrasound data were used to reduce the unknown parameters during the modeling optimization process. The results showed that pennation angles varied with joint angles, and the longhead TRI pennation from stroke group was smaller than the literature value. The maximum isometric muscle stress from persons after stroke was significantly smaller than that found in the unimpaired subjects. The prediction of joint torque fits well with the measured data from the control group, whereas the prediction error is larger in results from persons after stroke. In vivo parameters from ultrasound data could help to build a subject-specific biomechanical model of elbow extensor for both unimpaired and hemiplegic subjects, and then the results driven from the model could enhance the understanding of motor function changes for persons after stroke.

  13. Combining data sources to characterise climatic variability for hydrological modelling in high mountain catchments

    Science.gov (United States)

    Pritchard, David; Fowler, Hayley; Bardossy, Andras; O'Donnell, Greg; Forsythe, Nathan

    2016-04-01

    Robust hydrological modelling of high mountain catchments to support water resources management depends critically on the accuracy of climatic input data. However, the hydroclimatological complexity and sparse measurement networks typically characteristic of these environments present significant challenges for determining the structure of spatial and temporal variability in key climatic variables. Focusing on the Upper Indus Basin (UIB), this research explores how different data sources can be combined in order to characterise climatic patterns and related uncertainties at the scales required in hydrological modelling. Analysis of local observations with respect to underlying climatic processes and variability is extended relative to previous studies in this region, which forms a basis for evaluating the domains of applicability and potential insights associated with selected remote sensing and reanalysis products. As part of this, the information content of recent high resolution simulations for understanding climatic patterns is assessed, with particular reference to the High Asia Refined Analysis (HAR). A strategy for integrating these different data sources to obtain plausible realisations of the distributed climatic fields needed for hydrological modelling is developed on the basis of this analysis, which provides a platform for exploring uncertainties arising from potential biases and other sources of error. The interaction between uncertainties in climatic input data and alternative approaches to process parameterisation in hydrological and cryospheric modelling is explored.

  14. Combining generative and discriminative models for semantic segmentation of CT scans via active learning.

    Science.gov (United States)

    Iglesias, Juan Eugenio; Konukoglu, Ender; Montillo, Albert; Tu, Zhuowen; Criminisi, Antonio

    2011-01-01

    This paper presents a new supervised learning framework for the efficient recognition and segmentation of anatomical structures in 3D computed tomography (CT), with as little training data as possible. Training supervised classifiers to recognize organs within CT scans requires a large number of manually delineated exemplar 3D images, which are very expensive to obtain. In this study, we borrow ideas from the field of active learning to optimally select a minimum subset of such images that yields accurate anatomy segmentation. The main contribution of this work is in designing a combined generative-discriminative model which: i) drives optimal selection of training data; and ii) increases segmentation accuracy. The optimal training set is constructed by finding unlabeled scans which maximize the disagreement between our two complementary probabilistic models, as measured by a modified version of the Jensen-Shannon divergence. Our algorithm is assessed on a database of 196 labeled clinical CT scans with high variability in resolution, anatomy, pathologies, etc. Quantitative evaluation shows that, compared with randomly selecting the scans to annotate, our method decreases the number of training images by up to 45%. Moreover, our generative model of body shape substantially increases segmentation accuracy when compared to either using the discriminative model alone or a generic smoothness prior (e.g. via a Markov Random Field).

  15. A Model for Optimizing the Combination of Solar Electricity Generation, Supply Curtailment, Transmission and Storage

    Science.gov (United States)

    Perez, Marc J. R.

    /south bearing. Using technical and economic data reflecting today's real costs for solar generation technology, storage and electric transmission in combination with this model, we determined the minimum cost combination of these solutions to transform the variable output from solar plants into 3 distinct output profiles: A constant output equivalent to a baseload power plant, a well-defined seasonally-variable output with no weather-induced variability and a variable output but one that is 100% predictable on a multi-day ahead basis. In order to do this, over 14,000 model runs were performed by varying the desired output profile, the amount of energy curtailment, the penetration of solar energy and the geographic region across the continental United States. Despite the cost of supplementary electric transmission, geographic interconnection has the potential to reduce the levelized cost of electricity when meeting any of the studied output profiles by over 65% compared to when only storage is used. Energy curtailment, despite the cost of underutilizing solar energy capacity, has the potential to reduce the total cost of electricity when meeting any of the studied output profiles by over 75% compared to when only storage is used. The three variability mitigation strategies are thankfully not mutually exclusive. When combined at their ideal levels, each of the regions studied saw a reduction in cost of electricity of over 80% compared to when only energy storage is used to meet a specified output profile. When including current costs for solar generation, transmission and energy storage, an optimum configuration can conservatively provide guaranteed baseload power generation with solar across the entire continental United States (equivalent to a nuclear power plant with no down time) for less than 0.19 per kilowatt-hour. If solar is preferentially clustered in the southwest instead of evenly spread throughout the United States, and we adopt future expected costs for solar

  16. Combination of chemotherapy and cancer stem cell targeting agents: Preclinical and clinical studies.

    Science.gov (United States)

    Li, Yanyan; Atkinson, Katharine; Zhang, Tao

    2017-06-28

    The cancer stem cell model claims that the initiation, maintenance, and growth of a tumor are driven by a small population of cancer cells termed cancer stem cells. Cancer stem cells possess a variety of phenotypes associated with therapeutic resistance and often cause recurrence of the diseases. Several strategies have been investigated to target cancer stem cells in a variety of cancers, such as blocking one or more self-renewal signaling pathways, reducing the expression of drug efflux and ATP-binding cassette efflux transporters, modulating epigenetic aberrations, and promoting cancer stem cell differentiation. A number of cell and animal studies strongly support the potential benefits of combining chemotherapeutic drugs with cancer stem cell targeting agents. Clinical trials are still underway to address the pharmacokinetics, safety, and efficacy of combination treatment. This mini-review provides an updated discussion of these preclinical and clinical studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. [Study on artificial neural network combined with multispectral remote sensing imagery for forest site evaluation].

    Science.gov (United States)

    Gong, Yin-Xi; He, Cheng; Yan, Fei; Feng, Zhong-Ke; Cao, Meng-Lei; Gao, Yuan; Miao, Jie; Zhao, Jin-Long

    2013-10-01

    Multispectral remote sensing data containing rich site information are not fully used by the classic site quality evaluation system, as it merely adopts artificial ground survey data. In order to establish a more effective site quality evaluation system, a neural network model which combined remote sensing spectra factors with site factors and site index relations was established and used to study the sublot site quality evaluation in the Wangyedian Forest Farm in Inner Mongolia Province, Chifeng City. Based on the improved back propagation artificial neural network (BPANN), this model combined multispectral remote sensing data with sublot survey data, and took larch as example, Through training data set sensitivity analysis weak or irrelevant factor was excluded, the size of neural network was simplified, and the efficiency of network training was improved. This optimal site index prediction model had an accuracy up to 95.36%, which was 9.83% higher than that of the neural network model based on classic sublot survey data, and this shows that using multi-spectral remote sensing and small class survey data to determine the status of larch index prediction model has the highest predictive accuracy. The results fully indicate the effectiveness and superiority of this method.

  18. Modelling metal speciation in the Scheldt Estuary: Combining a flexible-resolution transport model with empirical functions

    Energy Technology Data Exchange (ETDEWEB)

    Elskens, Marc [Vrije Universiteit Brussel, Analytical, Pleinlaan 2, BE-1050 Brussels (Belgium); Gourgue, Olivier [Université catholique de Louvain, Institute of Mechanics, Materials and Civil Engineering (IMMC), 4 Avenue G. Lemaître, bte L4.05.02, BE-1348 Louvain-la-Neuve (Belgium); Université catholique de Louvain, Georges Lemaître Centre for Earth and Climate Research (TECLIM), Place Louis Pasteur 2, bte L4.03.08, BE-1348 Louvain-la-Neuve (Belgium); Baeyens, Willy [Vrije Universiteit Brussel, Analytical, Pleinlaan 2, BE-1050 Brussels (Belgium); Chou, Lei [Université Libre de Bruxelles, Biogéochimie et Modélisation du Système Terre (BGéoSys) —Océanographie Chimique et Géochimie des Eaux, Campus de la Plaine —CP 208, Boulevard du Triomphe, BE-1050 Brussels (Belgium); Deleersnijder, Eric [Université catholique de Louvain, Institute of Mechanics, Materials and Civil Engineering (IMMC), 4 Avenue G. Lemaître, bte L4.05.02, BE-1348 Louvain-la-Neuve (Belgium); Université catholique de Louvain, Earth and Life Institute (ELI), Georges Lemaître Centre for Earth and Climate Research (TECLIM), Place Louis Pasteur 2, bte L4.03.08, BE-1348 Louvain-la-Neuve (Belgium); Leermakers, Martine [Vrije Universiteit Brussel, Analytical, Pleinlaan 2, BE-1050 Brussels (Belgium); and others

    2014-04-01

    Predicting metal concentrations in surface waters is an important step in the understanding and ultimately the assessment of the ecological risk associated with metal contamination. In terms of risk an essential piece of information is the accurate knowledge of the partitioning of the metals between the dissolved and particulate phases, as the former species are generally regarded as the most bioavailable and thus harmful form. As a first step towards the understanding and prediction of metal speciation in the Scheldt Estuary (Belgium, the Netherlands), we carried out a detailed analysis of a historical dataset covering the period 1982–2011. This study reports on the results for two selected metals: Cu and Cd. Data analysis revealed that both the total metal concentration and the metal partitioning coefficient (K{sub d}) could be predicted using relatively simple empirical functions of environmental variables such as salinity and suspended particulate matter concentration (SPM). The validity of these functions has been assessed by their application to salinity and SPM fields simulated by the hydro-environmental model SLIM. The high-resolution total and dissolved metal concentrations reconstructed using this approach, compared surprisingly well with an independent set of validation measurements. These first results from the combined mechanistic-empirical model approach suggest that it may be an interesting tool for risk assessment studies, e.g. to help identify conditions associated with elevated (dissolved) metal concentrations. - Highlights: • Empirical functions were designed for assessing metal speciation in estuarine water. • The empirical functions were implemented in the hydro-environmental model SLIM. • Validation was carried out in the Scheldt Estuary using historical data 1982–2011. • This combined mechanistic-empirical approach is useful for risk assessment.

  19. Simulation model structure numerically robust to changes in magnitude and combination of input and output variables

    DEFF Research Database (Denmark)

    Rasmussen, Bjarne D.; Jakobsen, Arne

    1999-01-01

    instabilities prevent the practical use of such a system model for more than one input/output combination and for other magnitudes of refrigerating capacities.A higher numerical robustness of system models can be achieved by making a model for the refrigeration cycle the core of the system model and by using...... variables with narrow definition intervals for the exchange of information between the cycle model and the component models.The advantages of the cycle-oriented method are illustrated by an example showing the refrigeration cycle similarities between two very different refrigeration systems.......Mathematical models of refrigeration systems are often based on a coupling of component models forming a “closed loop” type of system model. In these models the coupling structure of the component models represents the actual flow path of refrigerant in the system. Very often numerical...

  20. Improved Lumped Models for Transient Combined Convective and Radiative Cooling of Multilayer Spherical Media

    Directory of Open Access Journals (Sweden)

    Chen An

    2017-01-01

    Full Text Available In this work, we studied the transient combined convection and radiation of multilayer spherical media with volumetric heat generation, extending the previous work on the particular case of a spherical body subjected to radiative cooling. The proposed lumped models were obtained through two-point Hermite approximations for the average temperature and heat flux in each layer. For the average temperature, the plain trapezoidal rule (H0,0 approximation was employed in all layers, except for the innermost layer, where the second-order two-side corrected trapezoidal rule (H2,1 approximation was utilized. For the heat flux, the plain trapezoidal rule (H0,0 approximation was employed for all the layers. The transient heat conduction in a TRISO-coated fuel particle being composed of five layers (namely, fuel kernel, buffer of porous carbon, inner pyrocarbon, silicon carbide, and outer pyrocarbon was analyzed using the proposed lumped models, the results of which were verified by comparison with the finite difference solution of the original distributed parameter model. Parametric studies were conducted to examine the effects of the dimensionless heat generation rate, the radiation-conduction parameter, and the Biot number on the temporal variations of the average temperatures.

  1. Modeling Soil Organic Carbon at Regional Scale by Combining Multi-Spectral Images with Laboratory Spectra.

    Science.gov (United States)

    Peng, Yi; Xiong, Xiong; Adhikari, Kabindra; Knadel, Maria; Grunwald, Sabine; Greve, Mogens Humlekrog

    2015-01-01

    There is a great challenge in combining soil proximal spectra and remote sensing spectra to improve the accuracy of soil organic carbon (SOC) models. This is primarily because mixing of spectral data from different sources and technologies to improve soil models is still in its infancy. The first objective of this study was to integrate information of SOC derived from visible near-infrared reflectance (Vis-NIR) spectra in the laboratory with remote sensing (RS) images to improve predictions of topsoil SOC in the Skjern river catchment, Denmark. The second objective was to improve SOC prediction results by separately modeling uplands and wetlands. A total of 328 topsoil samples were collected and analyzed for SOC. Satellite Pour l'Observation de la Terre (SPOT5), Landsat Data Continuity Mission (Landsat 8) images, laboratory Vis-NIR and other ancillary environmental data including terrain parameters and soil maps were compiled to predict topsoil SOC using Cubist regression and Bayesian kriging. The results showed that the model developed from RS data, ancillary environmental data and laboratory spectral data yielded a lower root mean square error (RMSE) (2.8%) and higher R2 (0.59) than the model developed from only RS data and ancillary environmental data (RMSE: 3.6%, R2: 0.46). Plant-available water (PAW) was the most important predictor for all the models because of its close relationship with soil organic matter content. Moreover, vegetation indices, such as the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), were very important predictors in SOC spatial models. Furthermore, the 'upland model' was able to more accurately predict SOC compared with the 'upland & wetland model'. However, the separately calibrated 'upland and wetland model' did not improve the prediction accuracy for wetland sites, since it was not possible to adequately discriminate the vegetation in the RS summer images. We conclude that laboratory Vis

  2. Combined physical and chemical nonequilibrium transport model: Analytical solution, moments, and application to colloids

    Science.gov (United States)

    The transport of solutes and colloids in porous media is influenced by a variety of physical and chemical nonequilibrium processes. A combined physical–chemical nonequilibrium (PCNE) model was therefore used to describe general mass transport. The model partitions the pore space into “mobile” and “i...

  3. Capstone Teaching Models: Combining Simulation, Analytical Intuitive Learning Processes, History and Effectiveness

    Science.gov (United States)

    Reid, Maurice; Brown, Steve; Tabibzadeh, Kambiz

    2012-01-01

    For the past decade teaching models have been changing, reflecting the dynamics, complexities, and uncertainties of today's organizations. The traditional and the more current active models of learning have disadvantages. Simulation provides a platform to combine the best aspects of both types of teaching practices. This research explores the…

  4. Modelling Combined Heat Exchange in the Leading Edge of Perspective Aircraft Wing

    Directory of Open Access Journals (Sweden)

    Kandinsky Roman O.

    2015-01-01

    Full Text Available In this paper gas dynamic numerical modelling of leading edge flow is presented and thermal loading parameters are determined. Numerical modelling of combined radiative and conductive heat transfer of the wing edge is carried out, thermal state of structure is given and the results are analyzed.

  5. Capstone Teaching Models: Combining Simulation, Analytical Intuitive Learning Processes, History and Effectiveness

    Science.gov (United States)

    Reid, Maurice; Brown, Steve; Tabibzadeh, Kambiz

    2012-01-01

    For the past decade teaching models have been changing, reflecting the dynamics, complexities, and uncertainties of today's organizations. The traditional and the more current active models of learning have disadvantages. Simulation provides a platform to combine the best aspects of both types of teaching practices. This research explores the…

  6. [Combined hopping-superexchange mechanism of charge transfer in DNA; a model with nearest interactions].

    Science.gov (United States)

    Lakhno, V D; Sultanov, V B

    2007-01-01

    In the framework of the earlier developed combined hopping-superexchange mechanism of charge transfer in DNA, a model with all nearest interactions between nucleobases is proposed. It is shown that the transfer rates for various types of nucleotide sequences calculated within this model are in a good agreement with experimental data.

  7. Description and application of the combined surface and groundwater flow model MOGROW

    NARCIS (Netherlands)

    Querner, E.P.

    1997-01-01

    In the Netherlands shallow groundwater tables prevail in many parts, such that groundwater and surface water are closely interlinked. Thus the use of a combined groundwater and surface water model is necessary to predict the effect of certain measures on a regional scale. Therefore the model MOGROW

  8. Modelling plant interspecific interactions from experiments of perennial crop mixtures to predict optimal combinations.

    Science.gov (United States)

    Halty, Virginia; Valdés, Matías; Tejera, Mauricio; Picasso, Valentín; Fort, Hugo

    2017-07-28

    The contribution of plant species richness to productivity and ecosystem functioning is a long standing issue in Ecology, with relevant implications for both conservation and agriculture. Both experiments and quantitative modelling are fundamental to the design of sustainable agroecosystems and the optimization of crop production. We modelled communities of perennial crop mixtures by using a generalized Lotka-Volterra model, i.e. a model such that the interspecific interactions are more general than purely competitive. We estimated model parameters -carrying capacities and interaction coefficientsfrom, respectively, the observed biomass of monocultures and bicultures measured in a large diversity experiment of seven perennial forage species in Iowa, United States. The sign and absolute value of the interaction coefficients showed that the biological interactions between species pairs included amensalism, competition, and parasitism (asymmetric positive-negative interaction), with various degrees of intensity. We tested the model fit by simulating the combinations of more than two species and comparing them with the polycultures experimental data. Overall, theoretical predictions are in good agreement with the experiments. Using this model, we also simulated species combinations that were not sown. From all possible mixtures (sown and not sown) we identified which are the most productive species combinations. Our results demonstrate that a combination of experiments and modelling can contribute to the design of sustainable agricultural systems in general and to the optimization of crop production in particular. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  9. The study of reconstitution of human ovarian carcinoma-severe combined immunodeficiency mice model%免疫重建荷人卵巢癌-严重联合免疫缺陷小鼠模型的建立

    Institute of Scientific and Technical Information of China (English)

    崔恒; 李艺; 童春容; 成夜霞; 冯捷; 刘蓓; 葛华; 钱和年

    2000-01-01

    目的:为研究卵巢癌的免疫治疗方法构建合适的动物模型.方法:严重联合免疫缺陷(severe combined immunodeficiency,SCID)小鼠皮下接种人卵巢癌细胞系SKOV3,同时腹腔注射人脾或外周血淋巴细胞进行免疫功能重建.观察成瘤情况;并用ELISA法检测鼠血清中人IgG含量以及流式细胞学和ABC免疫组织化学法测定鼠脾内人T细胞表型鉴定免疫重建.结果:免疫重建的小鼠成瘤率为89.6%,免疫组化证实皮下瘤保持原细胞系特征.3种方法检测发现用人外周血淋巴细胞免疫重建的效果优于用脾淋巴细胞.结论:免疫重建的荷人卵巢癌-SCID小鼠模型已初步建立成功.

  10. Vibrational spectrum and structure of CoO6: a model compound for molecular oxygen reversible binding on cobalt oxides and salts; a combined IR matrix isolation and theoretical study.

    Science.gov (United States)

    Marzouk, Asma; Danset, Delphine; Zhou, Ming Fei; Gong, Yu; Alikhani, Mohammad E; Manceron, Laurent

    2011-08-18

    The formation and structure of a novel species, a disuperoxo-cobalt dioxide complex (CoO(6)), has been investigated using matrix isolation in solid neon and argon, coupled to infrared spectroscopy and by quantum chemical methods. It is found that CoO(6) can be formed by successive complexation of cobalt dioxide by molecular oxygen without activation energy by diffusion of ground state O(2) molecules at 9K in the dark. The IR data on one combination and seven fundamentals, isotopic effects, and quantum chemical calculations are both consistent with an asymmetrical structure with two slightly nonequivalent oxygen ligands complexing a cobalt dioxide subunit. Evidence for other, metastable states is also presented, but the data are not complete. The electronic structure and formation pathway of this unique, formally +VI oxidation state, complex has been investigated using several functionals of current DFT within the broken-symmetry unrestricted formalism. It has been shown that the M06L pure local functional well reproduce the experimental observations. The ground electronic state is predicted to be an open shell (2)A'' doublet with the quartet states above by more than 9 kcal/mol and the sextet lying even higher in energy. The ground state has a strong and complex multireference character that hinders the use of more precise multireference approaches and requires caution in the methodology to be used. The geometrical, energetic, and vibrational properties have been computed.

  11. Saltstone SDU6 Modeling Study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Si Y. [Savannah River Site (SRS), Aiken, SC (United States); Hyun, Sinjae [Mercer University, Macon, GA (United States)

    2013-01-10

    A new disposal unit, designated as Saltstone Disposal Unit 6 (SDU6), is being designed for support of site accelerated closure goals and salt waste projections identified in the new Liquid Waste System Plan. The unit is a cylindrical disposal cell of 375 ft in diameter and 43 ft in height, and it has a minimum 30 million gallons of capacity. SRNL was requested to evaluate the impact of an increased grout placement height on the flow patterns radially spread on the floor and to determine whether grout quality is impacted by the height. The primary goals of the work are to develop the baseline Computational Fluid Dynamics (CFD) model and to perform the evaluations for the flow patterns of grout material in SDU6 as a function of elevation of grout discharge port and grout rheology. Two transient grout models have been developed by taking a three-dimensional multiphase CFD approach to estimate the domain size of the grout materials radially spread on the facility floor and to perform the sensitivity analysis with respect to the baseline design and operating conditions such as elevation height of the discharge port and fresh grout properties. For the CFD modeling calculations, air-grout Volume of Fluid (VOF) method combined with Bingham plastic and time-dependent grout models were used for examining the impact of fluid spread performance for the initial baseline configurations and to evaluate the impact of grout pouring height on grout quality. The grout quality was estimated in terms of the air volume fraction for the grout layer formed on the SDU6 floor, resulting in the change of grout density. The study results should be considered as preliminary scoping analyses since benchmarking analysis is not included in this task scope. Transient analyses with the Bingham plastic model were performed with the FLUENTTM code on the high performance parallel computing platform in SRNL. The analysis coupled with a transient grout aging model was performed by using ANSYS-CFX code

  12. Saltstone SDU6 Modeling Study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Si Y. [Savannah River Site (SRS), Aiken, SC (United States); Hyun, Sinjae [Mercer University, Macon, GA (United States)

    2013-01-10

    A new disposal unit, designated as Saltstone Disposal Unit 6 (SDU6), is being designed for support of site accelerated closure goals and salt waste projections identified in the new Liquid Waste System Plan. The unit is a cylindrical disposal cell of 375 ft in diameter and 43 ft in height, and it has a minimum 30 million gallons of capacity. SRNL was requested to evaluate the impact of an increased grout placement height on the flow patterns radially spread on the floor and to determine whether grout quality is impacted by the height. The primary goals of the work are to develop the baseline Computational Fluid Dynamics (CFD) model and to perform the evaluations for the flow patterns of grout material in SDU6 as a function of elevation of grout discharge port and grout rheology. Two transient grout models have been developed by taking a three-dimensional multiphase CFD approach to estimate the domain size of the grout materials radially spread on the facility floor and to perform the sensitivity analysis with respect to the baseline design and operating conditions such as elevation height of the discharge port and fresh grout properties. For the CFD modeling calculations, air-grout Volume of Fluid (VOF) method combined with Bingham plastic and time-dependent grout models were used for examining the impact of fluid spread performance for the initial baseline configurations and to evaluate the impact of grout pouring height on grout quality. The grout quality was estimated in terms of the air volume fraction for the grout layer formed on the SDU6 floor, resulting in the change of grout density. The study results should be considered as preliminary scoping analyses since benchmarking analysis is not included in this task scope. Transient analyses with the Bingham plastic model were performed with the FLUENTTM code on the high performance parallel computing platform in SRNL. The analysis coupled with a transient grout aging model was performed by using ANSYS-CFX code

  13. Development of a model for marburgvirus based on severe-combined immunodeficiency mice

    Directory of Open Access Journals (Sweden)

    Kalina Warren V

    2007-10-01

    Full Text Available Abstract The filoviruses, Ebola (EBOV and Marburg (MARV, cause a lethal hemorrhagic fever. Human isolates of MARV are not lethal to immmunocompetent adult mice and, to date, there are no reports of a mouse-adapted MARV model. Previously, a uniformly lethal EBOV-Zaire mouse-adapted virus was developed by performing 9 sequential passages in progressively older mice (suckling to adult. Evaluation of this model identified many similarities between infection in mice and nonhuman primates, including viral tropism for antigen-presenting cells, high viral titers in the spleen and liver, and an equivalent mean time to death. Existence of the EBOV mouse model has increased our understanding of host responses to filovirus infections and likely has accelerated the development of countermeasures, as it is one of the only hemorrhagic fever viruses that has multiple candidate vaccines and therapeutics. Here, we demonstrate that serially passaging liver homogenates from MARV-infected severe combined immunodeficient (scid mice was highly successful in reducing the time to death in scid mice from 50–70 days to 7–10 days after MARV-Ci67, -Musoke, or -Ravn challenge. We performed serial sampling studies to characterize the pathology of these scid mouse-adapted MARV strains. These scid mouse-adapted MARV models appear to have many similar properties as the MARV models previously developed in guinea pigs and nonhuman primates. Also, as shown here, the scid-adapted MARV mouse models can be used to evaluate the efficacy of candidate antiviral therapeutic molecules, such as phosphorodiamidate morpholino oligomers or antibodies.

  14. Establishment of rat model of combined kidney-adrenal gland allotransplantation

    Institute of Scientific and Technical Information of China (English)

    Yanjun Shi; Ruipeng Jia; Jiageng Zhu; Guangcheng Zhou

    2006-01-01

    Objective: To establish a rat model of combined kidney-adrenal gland and allotransplantation, and to explore the immunoprotecive effect of the transplanted adrenal gland on the transplanted kidney in the combined transplantation.Methods: SD rats 160 served as donors and recipients. The combined kidney-adrenal gland allotransplantation was performed.Infusion was conducted and prepared at prime position ,and the kidney and adrenal gland were at the left side. Direct vascular anastomosis and operation of connecting ureter attached part of bladder with the bladder were conducted. The kidney pedicle of the right side was ligated. Results: A stable and mature rat model of combined transplantation was established. The warm ischemia time was 30 seconds, and the cold ischemia time was 90-120min. The average time was 100 min. The operation time was 150 min.The survival time of the recipients was 21 days. The successful rate of the operation was 75%. Conclusion: The model of the combined kidney-adrenal gland allotransplantation can be established with higher successful rate. The model can be used to explore that transplanted adrenal gland may have immunoprotecive effect on the transplanted kidney in the combined transplantation.