Search results for "PROB"
showing 10 items of 8859 documents
Characterization of Streptomyces venezuelae ATCC 10595 rRNA gene clusters and cloning of rrnA
1996
Streptomyces venezuelae ATCC 10595 harbors seven rRNA gene clusters which can be distinguished by BglII digestion. The three rRNA genes present in each set are closely linked with the general structure 16S-23S-5S. We cloned rrnA and sequenced the 16S-23S spacer region and the region downstream of the 5S rRNA gene. No tRNA gene was found in these regions.
Sresa pārvarēšanas stratēģija un uzvedības problēmas pusaudžu vecuma zēniem un meitenēm
2018
Bakalaura darba mērķis ir izpētīt stresa pārvarēšanas stratēģiju saistību ar pusaudžu uzvedības problēmām un to atšķirības zēnu un meiteņu grupās. Pētījumā tika izvirzīti divi jautājumi. 1. Vai atšķiras stresa pārvarēšanas stratēģijas un uzvedības problēmu rādītāji pusaudžu zēniem un meitenēm? 2. Vai pastāv saistības starp stresa pārvarēšanas stratēģijām un pusaudžu zēnu un meiteņu uzvedības problēmām? Pētījumā piedalījās 65 respondenti – 31 meitene un 34 zēni, kas mācās kādas Rīgas mikrorajona vispārizglītojošās skolas 8. un 9. klasē. Respondentu vecums: 14-16 gadi. Lai gūtu atbildes uz izvirzītajiem pētījuma jautājumiem, tika izmantota Ahenbaha jauniešu pašnovērtējuma aptauja (vecums 11-1…
Surface effects, boundary conditions and evolution laws within second strain gradient plasticity
2014
Abstract The principle of the virtual power (PVP) is used in conjunction with the concepts of “energy residual” and “insulation condition” to address second strain gradient plasticity. The energy residual with its typical divergence format is an extra stress power playing the role of basic state variable to describe the gradient effects, whereas the insulation condition constitutes a global energy characterization of the body as part of the body/environment system. The microstructure of a second strain gradient material (but not of a first strain gradient one) is shown to exhibit surface effects with the formation of a thin boundary layer. This boundary layer is in local (and global) equili…
Stress fields in general composite laminates
1996
A direct approach is employed to obtain a general boundary integral formulation for the analysis of composite laminates subjected to uniform axial strain. The integral equations governing the problem are directly deduced from the reciprocity theorem, employing the generalized orthotropic elasticity fundamental solutions expressly inferred. The solution is achieved by the boundary element method, which gives, once the traction-free boundary conditions and the interfacial continuity conditions are enforced, a linear system of algebraic equations. The formulation does not present restrictions with regard to the laminate stacking sequence and it does not require any aprioristic assumption. The …
A unifying variational framework for stress gradient and strain gradient elasticity theories
2015
Abstract Stress gradient elasticity and strain gradient elasticity do constitute distinct continuum theories exhibiting mutual complementary features. This is probed by a few variational principles herein presented and discussed, which include: i) For stress gradient elasticity, a (novel) principle of minimum complementary energy and an (improved-form) principle of stationarity of the Hellinger–Reissner type; ii) For strain gradient elasticity, a (known) principle of minimum total potential energy and a (novel) principle of stationarity of the Hu–Washizu type. Additionally, the higher order boundary conditions for stress gradient elasticity, previously derived by the author (Polizzotto, Int…
Numerical simulation of resonant activation in a fluctuating metastable model system
1998
We study the escape time from a metastable overdamped model system in the presence of two noise sources: a white noise and a random telegraph noise. The random telegraph noise controls the height of the potential barrier of the metastable system while the white noise mimics the presence of a given temperature. We report on numerical simulations about: (i) the average residence time of the system in the metastable state; (ii) the probability density function (PDF) of the residence time at various values of the correlation time T c of the random telegraph noise. Resonant activation is observed in the dynamics of the investigated system. The PDF shows different shapes for different values of τ…
Constrained and unconstrained problems in location theory and inner products
1997
In a real normed space X the optimization problem associated to a finite subset and to a family of positive weights with the objective function [UM0001] has some well known properties when X is an ...
Calculation of modification of alkali metal atomic transition probability in strong external magnetic field and its application
2010
International audience; Interaction of alkali atoms with external magnetic field induced a splitting and a shift of their energy levels. We have study this interaction for external field from 0 to 5000 Gauss when the alkali vapor is confined in submicron thin vapor cell with thickness L = λ/2. Rubidium and Sodium vapors have been studied. The Hamiltonian can be expressed as the sum of the unperturbated atomic Hamiltonian and the so-called Zeeman Hamiltonian. The probability of a transition, induced by the laser electric field is proportional to the square of the transfer coefficients modified by the presence of the magnetic field. We will show that the strong nonlinearity of the transition …
Nonlinear Nonhomogeneous Elliptic Problems
2019
We consider nonlinear elliptic equations driven by a nonhomogeneous differential operator plus an indefinite potential. The boundary condition is either Dirichlet or Robin (including as a special case the Neumann problem). First we present the corresponding regularity theory (up to the boundary). Then we develop the nonlinear maximum principle and present some important nonlinear strong comparison principles. Subsequently we see how these results together with variational methods, truncation and perturbation techniques, and Morse theory (critical groups) can be used to analyze different classes of elliptic equations. Special attention is given to (p, 2)-equations (these are equations driven…
THE MINIMIZING TOTAL VARIATION FLOW WITH MEASURE INITIAL CONDITIONS
2004
In this paper we obtain existence and uniqueness of solutions for the Cauchy problem for the minimizing total variation flow when the initial condition is a Radon measure in ℝN. We study limit solutions obtained by weakly approximating the initial measure μ by functions in L1(ℝN). We are able to characterize limit solutions when the initial condition μ=h+μs, where h∈L1(ℝN)∩L∞(ℝN), and μs=αℋk⌊ S,α≥0,k is an integer and S is a k-dimensional manifold with bounded curvatures. In case k<N-1 we prove that the singular part of the solution does not move, it remains equal to μs for all t≥0. In particular, u(t)=δ0 when u(0)=δ0. In case k=N-1 we prove that the singular part of the limit solution …