Search results for " Validation"
showing 10 items of 313 documents
Validation of models for sprays
2016
We consider complex fluids consisting of a dispersed phase (solid particles or liquid droplets) immersed in a gas. A class of models describing the dynamics of such a kind of systems is given by a system of partial differential equations where a kinetic equation, describing the dispersed phase, is coupled to a fluid equation for the background gas. The coupling is given by the drag force exerted by the gas on the dispersed phase. Within this class, we shall analyse the case where the kinetic equation is a Vlasov-type equation and the fluid equation are of Stokes or Navier-Stokes type. We shall discuss the validation problem for this class of models, i.e. the derivation of the equations of t…
Profiled support vector machines for antisense oligonucleotide efficacy prediction.
2004
Abstract Background This paper presents the use of Support Vector Machines (SVMs) for prediction and analysis of antisense oligonucleotide (AO) efficacy. The collected database comprises 315 AO molecules including 68 features each, inducing a problem well-suited to SVMs. The task of feature selection is crucial given the presence of noisy or redundant features, and the well-known problem of the curse of dimensionality. We propose a two-stage strategy to develop an optimal model: (1) feature selection using correlation analysis, mutual information, and SVM-based recursive feature elimination (SVM-RFE), and (2) AO prediction using standard and profiled SVM formulations. A profiled SVM gives d…
Assessing model accuracy using the homology modeling automatically software
2007
Homology modeling is a powerful technique that greatly increases the value of experimental structure determination by using the structural information of one protein to predict the structures of homologous proteins. We have previously described a method of homology modeling by satisfaction of spatial restraints (Li et al., Protein Sci 1997;6:956-970). The Homology Modeling Automatically (HOMA) web site,http://www-nmr.cabm.rutgers.edu/HOMA, is a new tool, using this method to predict 3D structure of a target protein based on the sequence alignment of the target protein to a template protein and the structure coordinates of the template. The user is presented with the resulting models, togeth…
Statistical Techniques for Validation of Simulation and Analytic Stochastic Models
2014
In this paper, we consider the problem of statistical validation of multivariate stationary response simulation and analytic stochastic models of observed systems (say, transportation or service systems), which have p response variables. The problem is reduced to testing the equality of the mean vectors for two multivariate normal populations. Without assuming equality of the covariance matrices, it is referred to as the Behrens–Fisher problem. The main purpose of this paper is to bring to the attention of applied researchers the satisfactory tests that can be used for testing the equality of two normal mean vectors when the population covariance matrices are unknown and arbitrary. To illus…
Structure Validation of Natural Products by Quantum-Mechanical GIAO Calculations of 13C NMR Chemical Shifts GIAO=gauge including atomic orbitals.
2002
Geometry optimization and GIAO (gauge including atomic orbitals) 1 3 C NMR chemical shift calculations at Hartree-Fock level, using the 6-31G(d) basis set, are proposed as a tool to be applied in the structural characterization of new organic compounds, thus providing useful support in the interpretation of experimental NMR data. Parameters related to linear correlation plots of computed versus experimental 1 3 C NMR chemical shifts for fourteen low-polar natural products, containing 10-20 carbon atoms, were employed to assess the reliability of the proposed structures. A comparison with the hybrid B3LYP method was carried out to evaluate electron correlation contributions to the calculatio…
Positive/negative symptomatology and experimental measures of attention in schizophrenic patients.
1993
In a search for an external validation of the negative syndrome construct and the attentional impairment item on Andreasen's scale, 49 unmedicated schizophrenic patients were administered the Span of Apprehension Test and a Continuous Performance Test with two levels of difficulty. This schizophrenic sample performed significantly more poorly on the attentional tests than a comparable group of 27 healthy control subjects. Depending on the difficulty of the test we found a number of significant correlations between the SANS composite score and the pertaining attentional impairment item on the one hand and experimental indices of attentional functioning on the other hand, which might corrobor…
Simultaneous analysis of twenty-six mycotoxins in durum wheat grain from Italy
2016
Abstract A multi-mycotoxin analysis method based on liquid chromatography coupled to triple quadrupole mass spectrometry was validated and applied for the determination of twenty-six mycotoxins, including eight trichothecenes, three fumonisins, sterigmatocystin, ochratoxin A, four aflatoxins, zearalenone, five “emerging” mycotoxins and three Alternaria mycotoxins in 74 durum wheat samples from central Italy. Eighty-eight percent of the analysed samples contained one or more mycotoxins, with enniatin B showing the highest contamination levels (78% of samples with levels ranging from 23 to 1826 ng/g), followed by enniatin B1 (10–1384 ng/g) and deoxynivalenol (48–2267 ng/g). This work gives an…
Staging systems of hepatocellular carcinoma: A review of literature
2013
Hepatocellular carcinoma (HCC) is a major health problem with a high incidence and mortality all over the world. Natural history of HCC is severe and extremely variable, and prognostic factors influencing outcomes are incompletely defined. Over time, many staging and scoring systems have been proposed for the classification and prognosis of patients with HCC. Currently, the non-ideal predictive performance of existing prognostic systems is secondary to their inherent limitations, as well as to a non-universal reproducibility and transportability of the results in different populations. New serological and histological markers are still under evaluation with promising results, but they requi…
Expression of clec9a in the oral cancer microenvironment. A preliminary immunohistochemical pilot study
2021
Background The search for treatments to improve cancer survival has led to the emergence of immunotherapy and the study of the tumour microenvironment existing in neoplasms. This preliminary study aims to understand the clinical and pathological relationship of clec9a expression in oral cancer and to explore survival models for future studies. Material and methods: Immunohistochemical study that included 26 patients with a diagnosis of oral squamous cell carcinoma (OSCC) in mobile tongue and floor of the mouth. Clinical and histopathological variables were recorded, and the biomarkers clec9a for dendritic cells and CD8 and CD4 for lymphocytes were used. Results Clec9a was expressed in 58% o…
Correlation, hierarchies, and networks in financial markets
2010
We discuss some methods to quantitatively investigate the properties of correlation matrices. Correlation matrices play an important role in portfolio optimization and in several other quantitative descriptions of asset price dynamics in financial markets. Specifically, we discuss how to define and obtain hierarchical trees, correlation based trees and networks from a correlation matrix. The hierarchical clustering and other procedures performed on the correlation matrix to detect statistically reliable aspects of the correlation matrix are seen as filtering procedures of the correlation matrix. We also discuss a method to associate a hierarchically nested factor model to a hierarchical tre…