Universality in adsorbate ordering on nanotube surfaces

Numerically efficient transfer matrix technique for studying statistics of coherent adsorbates on small nanotubes has been developed. In the framework of a realistic microscopic model fitted to the data of ab initio calculations taken from literature sources, the ordering of potassium adsorbate on (6,0) single-walled carbon nanotube has been studied. Special attention has been payed to the phase transition-like abrupt changes seen in the adsorption isotherms at low temperature. It has been found that the behavior during the transitions conforms with the universality hypothesis of the theory of critical phenomena and is qualitatively the same as in the one dimensional Ising model. Quantitatively the critical behavior can be fully described by two parameters. Their qualitative connection with the properties of interphase boundaries is suggested but further research is needed to develop a quantitative theory.Comment: 11 pages, 6 figures; some typos correcte

Rigorous results on the local equilibrium kinetics of a protein folding model

A local equilibrium approach for the kinetics of a simplified protein folding model, whose equilibrium thermodynamics is exactly solvable, was developed in [M. Zamparo and A. Pelizzola, Phys. Rev. Lett. 97, 068106 (2006)]. Important properties of this approach are (i) the free energy decreases with time, (ii) the exact equilibrium is recovered in the infinite time limit, (iii) the equilibration rate is an upper bound of the exact one and (iv) computational complexity is polynomial in the number of variables. Moreover, (v) this method is equivalent to another approximate approach to the kinetics: the path probability method. In this paper we give detailed rigorous proofs for the above results.Comment: 25 pages, RevTeX 4, to be published in JSTA

Accelerated kinetic Monte Carlo algorithm for diffusion limited kinetics

If a stochastic system during some periods of its evolution can be divided into non-interacting parts, the kinetics of each part can be simulated independently. We show that this can be used in the development of efficient Monte Carlo algorithms. As an illustrative example the simulation of irreversible growth of extended one dimensional islands is considered. The new approach allowed to simulate the systems characterized by parameters superior to those used in previous simulations.Comment: 4 pages, 4 figures, to be published in Phys. Rev.

Peculiarities of preparation of a vocational teacher for use of application software taking into account the requirements of the federal state education standard

The significance of the issue under study is due to the fact that nowadays there is a necessity of rethinking of conception of training future vocational teachers to use application software taking into account a competency-based approach. The article is aimed at studying the contradictions underscored while analyzing the conditions of the process of preparation of future vocational teachers for using application software within the educational process and also the ways of their solving realized with the help of the competency-based approach. The competency-based approach allows forming a system of requirements for the practical part of the research based on technology of project education. In the given research work the authors' viewing of principles of formation of conditions of preparation of the vocational teachers for using the application software within the education process is presented. The analysis of groups of conditions is made with regard to the discipline "Information Technologies in Education." With the use of traditional vision ("to know, to be able, to have") and vision from the point of view of Dublin descriptors. The contents of the article could be of interest for teachers who are engaged into training the Bachelors of Vocational Education (branch-wise) and also retraining in the sphere of use of the application software in the education process. © Authors

Deficient calcium, zinc, and iron intake on absorption of cadmium from diet

Background/Aim: In vitro and in vivo studies have demonstrated that deficient calcium, zinc, and iron dietary intake upregulates metal ion transporters to increase intestinal absorption. However, these gut transporters are not specific and bind to other metals, including cadmium. Few human studies have investigated whether deficient calcium, zinc, and iron intake increases intestinal absorption of dietary cadmium. Methods: We used enrollment data (2010-2012) from the Study of Environment, Lifestyle & Fibroids, a cohort of 1693 African American women ages 23-35 who reside in the Detroit, Michigan area. Whole blood cadmium concentrations (proxy for cadmium absorption) were measured in 1548 participants. Dietary and supplemental calcium, zinc, and iron intake was estimated using Block 2005 Food Frequency Questionnaire data; deficient intake was defined as <80% of the recommended daily allowance. Daily dietary intake of total grains was used as the proxy for dietary cadmium intake as grains are a major source of cadmium exposure in U.S. diet. We estimated the percent difference in blood cadmium concentrations per median daily intake of total grains (4.55 ounce equivalents) using multivariable linear regression, stratified by deficient and sufficient calcium, zinc, and/or iron intake. We restricted the analyses to never smokers with plausible values for total energy intake (>400 and <5000 kcal/day) (n=1087). We adjusted for age at enrollment, total energy intake, body mass index, height, education, and natural log-transformed blood lead concentrations. Results: The observed percent difference in blood cadmium concentrations in relation to intake of total grains was stronger among those with deficient intake of calcium, zinc, and/or iron (28%, 95% CI; 6, 53%) than among those with sufficient intake of all 3 essential nutrients (5%, 95% CI: -7, 19%). Conclusions: Our preliminary findings suggest that women with deficient calcium, zinc, and/or iron intake have increased absorption of cadmium from the diet

Kinetostatics of Wheel Vehicle in the Category of Spiral-Screw Routes

International audienceDeterministic mathematical model of kinetostatics of wheel vehicle in terms of different modes of spatial motion in the context of curved route is proposed. Earth-based coordinate system is introduced which pole and axial orientation are determined by the convenience of route description as well as vehicle-related coordinates which pole axial orientation are determined within inertial space with the help of natural trihedral. Turn of the natural trihedral within inertial coordinates is described by means of quaternion matrices in the context of Rodrigues-Hamilton parameters. Rodrigues-Hamilton parameters are in matrix form in direct accordance with specified hodograph. Kinetostatics of wheel vehicle is considered in terms of spatial motion with an allowance for three-dimensional aerodynamic forces, gravity, and tangential and centrifugal inertial forces. In the context of spiral-screw lines deterministic mathematical model of wheel vehicle kinetostatics is proposed in the form of hodograph in terms of uniform motion, accelerated motion, and decelerated motion within following route sections: straight and horizontal; in terms of vertical grade; in terms of horizontal plane. Analytical approach to determine animated contact drive-control forces of wheel vehicle for structural diagrams having one and two support points involving of a driving-driven wheel characteristic is proposed based on kinetostatics equations. Mathematical model of wheel vehicle kinetostatics in terms of spatial motion is constructed on the basis of nonlinear differential Euler-Lagrange equations; it is proposed to consider physically implemented motion trajectories of wheel vehicles in the context of spiral-screw lines; hodograph determines spatial displacement; Rodrigues-Hamilton parameters determines spatial turn; Varignon theorem is applied to identify components of drive (control) force. The obtained results make it possible to solve a wide range of problems connected with dynamic design of wheel vehicles involving controllability, and estimation of dynamic load of both system and support surface

Interaction of Saturn's magnetosphere and its moons: 2. Shape of the Enceladus plume

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95207/1/jgra20314.pd