Search results for "CONTROL"
showing 10 items of 13168 documents
Modeling of defects and surfaces in perovskite ferroelectrics
2002
The results of electronic structure calculations for different terminations of SrTiO3 (100) and (110) perovskite thin films are discussed. These calculations are based on the ab initio Hartree-Fock (HF) method and Density Functional Theory (DFT). Results are compared with previous ab initio plane-wave LDA and classical Shell Model (SM) calculations. Calculated considerable increase of the Ti – O chemical bond covalency nearby the surface is confirmed by experimental data. Our quantum chemical calculations performed by means of the intermediate neglect of differential overlap (INDO) method confirm the existence of self-trapped electrons in KNbO3, KTaO3 and BaTiO3 crystals. The relevant latti…
Apprentissage automatique de réseaux d'interaction à partir de données de séquences de nouvelle génération
2022
Climate change and other human-induced processes are modifying ecosystems, globally, at an ever increasing rate. Microbial communities play an important role in the functioning ecosystems, maintaining their diversity and services. These communities are shaped by the different abiotic environmental effects to which they are subjected and the biotic interactions between all community members. The ANR Next-Generation Biomonitoring (NGB) project proposed to reconstruct interaction networks from abundance measures obtained sequencing environmental DNA (eDNA) and to use these networks to monitor ecosystem change. In this thesis, conducted as part of the NGB project, I evaluate the potential of tw…
A generalization of Françoise's algorithm for calculating higher order Melnikov functions
2002
Abstract In [J. Differential Equations 146 (2) (1998) 320–335], Francoise gives an algorithm for calculating the first nonvanishing Melnikov function Ml of a small polynomial perturbation of a Hamiltonian vector field and shows that Ml is given by an Abelian integral. This is done under the condition that vanishing of an Abelian integral of any polynomial form ω on the family of cycles implies that the form is algebraically relatively exact. We study here a simple example where Francoise's condition is not verified. We generalize Francoise's algorithm to this case and we show that Ml belongs to the C [ log t,t,1/t] module above the Abelian integrals. We also establish the linear differentia…
The soil as a reservoir for antagonists to plant diseases
2007
The soil is often considered the milieu providing support for plant roots, water and nutrients for plant growth. But it is also considered a hostile environment harbouring plant pathogenic nematodes, bacteria and fungi. The most common attitude is to try to eliminate the plant pathogenic organisms by biocidal treatments such as methyl bromide fumigation, which are dangerous for man and the environment. Beside this pathogen eradication strategy, another approach to control soil-borne plant diseases consists in studying the plant-pathogen interactions at the cellular and molecular level to create new resistant cultivars or to develop new plant protection products based on elicitation of plant…
Bacterial community response to changes in a tri-trophic cascade during a whole-lake fish manipulation
2015
Microbial communities play a key role in biogeochemical processes by degrading organic material and recycling nutrients, but can also be important food sources for upper trophic levels. Trophic cascades might modify microbial communities either directly via grazing or indirectly by inducing changes in other biotic or in abiotic factors (e.g., nutrients). We studied the effects of a tri-trophic cascade on microbial communities during a whole-lake manipulation in which European perch (Perca fluviatilis) were added to a naturally fishless lake divided experimentally into two basins. We measured environmental parameters (oxygen, temperature, and nutrients) and zooplankton biomass and studied th…
A heuristic algorithm for project scheduling with splitting allowed
1996
In this article, we analyze the precedence diagramming method, the only published algorithm for time-only project scheduling with activity splitting allowed. The criteria used in this method (forward and backward pass computations) for deciding when an activity has to be interrupted are shown to be invalid in some situations. We look into the causes of these failures and propose new formulae that always provide feasible solutions. The new algorithm has been tested on 240 randomly generated problems ranging up to 600 activities and 7,200 precedence relationships, resulting in an average deviation from optima of less than 1 percent.
Civilidad y Buen gobierno: la "Policía" en el siglo XVIII
2008
El concepto y la práctica de la "policía" son una de las áreas más importantes desde finales del siglo XVII. Si estudiamos ese concepto y esa práctica podremos ver cómo las monarquías absolutas europeas desarrollan una nueva racionalidad de lo "político". De hecho, ambos términos fueron durante mucho tiempo sinónimos; ambos términos, la "policía" y la "política" en el siglo XVIII, tienen que ver con un ámbito de actuación global. Éste incluía lo material y lo espiritual, las cosas y los hombres, la producción y la ordenación de la riqueza, y también una nueva sociabilidad y una nueva "civilización". Era el arte del "buen gobierno". En este artículo repasamos los diversos modelos de desarrol…
Experimental investigation of holes interaction effect on the sound absorption coefficient of micro-perforated panels under high and medium sound lev…
2011
Abstract This paper experimentally investigates the holes interaction effect on the sound absorption coefficient of micro-perforated panels under high and medium sound levels. The theoretical formulations are based on a semi-empirical approach and the use of Fok’s function to model the acoustic surface impedance. For the high sound level regime, an empirical power law involving three coefficients is adapted. It is shown theoretically and experimentally that these coefficients can lead to optimized absorption performance and particularly, a formula relating the critical Reynolds number (Reynolds number value after which the absorption coefficient decreases with the increase of sound level) a…
Lung on a Chip Development from Off-Stoichiometry Thiol–Ene Polymer
2021
Institute of Solid-State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2. Finally, we would like to thank Biol. Kaspars Tars from Latvian Biomedical research and study center for giving us the opportunity to participate in this consortium and contribute to Latvian scientists’ effort in response to the COVID-19 pandemic.
Quantitative analysis of the effect of controlled-release formulation on nonlinear gastrointestinal absorption of P-glycoprotein substrate talinolol …
2020
Abstract Oral absorption of talinolol, a substrate of P-glycoprotein (P-gp), from a sustained-release (SR) formulation was reportedly decreased compared to that from an immediate-release (IR) formulation. The aim of this study was to predict and understand the effect of controlled-release formulation on the oral absorption of P-gp substrates by developing a physiologically based pharmacokinetic (PBPK) absorption model incorporating multiple kinetic parameters obtained from in vitro studies, using talinolol as a model substrate. Simulation analysis using the developed PBPK absorption model indicated that the clinically observed marked decrease in the plasma concentration of talinolol adminis…