Search results for "Efficient"
showing 10 items of 1603 documents
Nonlinear parametric quantile models
2020
Quantile regression is widely used to estimate conditional quantiles of an outcome variable of interest given covariates. This method can estimate one quantile at a time without imposing any constraints on the quantile process other than the linear combination of covariates and parameters specified by the regression model. While this is a flexible modeling tool, it generally yields erratic estimates of conditional quantiles and regression coefficients. Recently, parametric models for the regression coefficients have been proposed that can help balance bias and sampling variability. So far, however, only models that are linear in the parameters and covariates have been explored. This paper …
Main individual and product characteristics influencing in-mouth flavour release during eating masticated food products with different textures: mech…
2013
Research Areas: Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology; A mechanistic model predicting flavour release during oral processing of masticated foods was developed. The description of main physiological steps (product mastication and swallowing) and physical mechanisms (mass transfer, product breakdown and dissolution) occurring while eating allowed satisfactory simulation of in vivo release profiles of ethyl propanoate and 2-nonanone, measured by Atmospheric Pressure Chemical Ionization Mass Spectrometry on ten representative subjects during the consumption of four cheeses with different textures. Model sensitivity analysis showed that the main paramet…
Multivariate Nonparametric Tests
2004
Multivariate nonparametric statistical tests of hypotheses are described for the one-sample location problem, the several-sample location problem and the problem of testing independence between pairs of vectors. These methods are based on affine-invariant spatial sign and spatial rank vectors. They provide affine-invariant multivariate generalizations of the univariate sign test, signed-rank test, Wilcoxon rank sum test, Kruskal–Wallis test, and the Kendall and Spearman correlation tests. While the emphasis is on tests of hypotheses, certain references to associated affine-equivariant estimators are included. Pitman asymptotic efficiencies demonstrate the excellent performance of these meth…
New complex polycyclic compounds: Synthesis, antiproliferative activity and mechanism of action
2020
Abstract Polycyclic or O-glycoconiugate polycyclic compounds 1a-g were previously tested for their in vitro antiproliferative activity. In this series of compounds, activity increases as log P decreases. Specifically, compounds 1d and 1g showed lower log P values together with the best antiproliferative profiles. With the aim of extending our understanding of the structure–activity relationship (SAR) of this class of compounds, we prepared new polycyclic derivatives 2a-c, which bear on each of the two phenyl rings hydrophilic substituents (OH, SO2NH2 or NHCOCH3). These substituents are able to form hydrogen bonds and to decrease the partition coefficient value as compared with compound 1d. …
Macromolecules in ordered media: 4. Poly(2-vinyl pyridine)-liposome association induced by electrostatic interactions
1997
Abstract We have investigated the interaction between vesicles based on dimyristoyl phosphatidic acid (DMPA) and a polymer, such as poly(2-vinyl pyridine) (P2VPy), on the basis of both partition and binding models. The resulting association curves are non monotonous being three regions clearly evidenced. The electrostatic and steric origin of the attractive or repulsive interactions are analyzed as a function of pH, ionic strength and temperature using the fluorescence spectroscopy technique. We emphasize the importance of differentiating the ideal definition of the binding constant from the theoretically evaluated including the activity coefficient, γ, to take into account shifts from the …
A spatially resolved investigation of oxygen adsorption on polycrystalline copper and titanium by means of photoemission electron microscopy
2004
Abstract The interaction of oxygen with polycrystalline copper and titanium surfaces was studied by means of photoemission electron microscopy. Variations in the image brightness were used to determine the work function of different Cu crystallites. The change of the work function was monitored during oxygen adsorption on both, Cu and Ti. Those changes are smooth for Cu whereas different Ti crystallites exhibit a rather complicated behavior during oxygen adsorption. The transformation of brightness versus exposure curves into work function versus coverage curves allows to determine the initial dipole moment of the adsorbed oxygen atoms. A value of about 20 mD was found for O on Cu(1 1 0). V…
Sticking Probability on Zeolites
2006
The sticking coefficient, i.e., the probability that, on hitting the surface of a nanoporous particle (zeolite), a molecule shall be able to enter the intracrystalline space, is a key quantity for the application of such materials in heterogeneous catalysis and molecular sieving. On the basis of pulsed field gradient NMR diffusion measurements and molecular dynamics simulations, typical values of this probability are found to be close to one. They exceed previous estimates on the basis of IR uptake measurements by many orders of magnitude.
The influence of the “hot”-dimer adsorption mechanism on the kinetics of a monomer-dimer surface reaction
1993
“Hot” dimers are molecules which after adsorption dissociate and each of the remaining “hot” monomers fly apart up to a maximum distance R from the original adsorption site. The influence of the “hot”-dimer adsorption mechanism on relevant aspects of the bimolecular catalyzed reaction of the type A − (1/2)B2(“hot”) → AB is studied by means of the Monte-Carlo simulation technique. The temporal evolution of both the reactant's coverages as well as the rate of AB-production is evaluated and discussed. Due to the enhanced probability of “hot” species for encounters with other adsorbed particles, the rate of AB-production becomes faster when increasing R. This behavior may be relevant in the dyn…
A dish-stirling solar concentrator coupled to a seasonal thermal energy storage system in the southern mediterranean basin: A cogenerative layout hyp…
2020
Abstract In the future, renewable energy sources will increasingly represent an efficient energy source capable of meeting the demands of residential and industrial buildings avoiding the emissions of greenhouse gases into the atmosphere. In this paper, a heat and electric power cogeneration plant implementing a field of dish-Stirling collectors, a seasonal geothermal storage and a system of water-to-water heat pumps is proposed for the first time. The cogeneration plant has been designed both to supply thermal energy to the heating system of Building 9 of the Department of Engineering in Palermo and to produce electricity. The operation of the plant has been tested by means of hourly-based…
Higher order matrix differential equations with singular coefficient matrices
2015
In this article, the class of higher order linear matrix differential equations with constant coefficient matrices and stochastic process terms is studied. The coefficient of the highest order is considered to be singular; thus, rendering the response determination of such systems in a straightforward manner a difficult task. In this regard, the notion of the generalized inverse of a singular matrix is used for determining response statistics. Further, an application relevant to engineering dynamics problems is included.