Search results for " function"

A study of Wigner functions for discrete-time quantum walks

2013

We perform a systematic study of the discrete time Quantum Walk on one dimension using Wigner functions, which are generalized to include the chirality (or coin) degree of freedom. In particular, we analyze the evolution of the negative volume in phase space, as a function of time, for different initial states. This negativity can be used to quantify the degree of departure of the system from a classical state. We also relate this quantity to the entanglement between the coin and walker subspaces.

Estimating the temperature evolution of foodstuffs during freezing with a 3D meshless numerical method

2015

Abstract Freezing processes are characterised by sharp changes in specific heat capacity and thermal conductivity for temperatures close to the freezing point. This leads to strong nonlinearities in the governing PDE that may be difficult to resolve using traditional numerical methods. In this work we present a meshless numerical method, based on a local Hermite radial basis function collocation approach in finite differencing mode, to allow the solution of freezing problems. By introducing a Kirchhoff transformation and solving the governing equations in Kirchhoff space, the strength of nonlinearity is reduced while preserving the structure of the heat equation. In combination with the hig…

Dynamic reliability indices for k-out-of-n multi-state system

2005

A multi-state system k-out-of-n is one of basic models in reliability analysis. In this system, k is the minimum number of n components that must work for the system to work and both the system and its components can have more than two states. A structure function declares relation between system and component states uniquely. New algorithm for reliability analysis of the k-out-of-n multi-state system is proposed in this paper. We use two tools for examine this system: (a) structure function for the system description; (b) direct partial logic derivatives for analysis this system. New algorithm for reliability analysis of the multi-state system k-out-of-n is allowed to calculate the probabi…

Structural, energetic and kinetic database of catalytic reactions: Benzyl alcohol to benzaldehyde oxidation on MnOx clusters

2021

Abstract Data here reported are connected with the research article “Benzyl Alcohol to Benzaldehyde Oxidation on MnO x Clusters: Unraveling Atomistic Features” Gueci et al. [1] . This work described and discussed structural and energetic results, calculated by Density Functional Theory (DFT). In order to get kinetic information, DFT results were refined by an original approach, which will be shortly described in the following article. The crossed analysis of experimental and computational energetic and kinetic data allowed to (i) reconstruct the complicated lattice that connects the primary and secondary mechanisms of the reaction and (ii) identify alternative process pathways capable of by…

Ferromagnetic kinetic exchange interaction in magnetic insulators

2020

The superexchange theory predicts dominant antiferromagnetic kinetic interaction when the orbitals accommodating magnetic electrons are covalently bonded through diamagnetic bridging atoms/groups. Here we show that explicit consideration of magnetic and (leading) bridging orbitals, together with the electron transfer between the former, reveals a strong ferromagnetic kinetic exchange contribution. First principle calculations show that it is comparable in strength with antiferromagnetic superexchange in a number of magnetic materials with diamagnetic metal bridges. In particular, it is responsible for a very large ferromagnetic coupling ($-10$ meV) between the iron ions in a Fe$^{3+}$-Co$^{…

Layer-Wise Discontinuous Galerkin Methods for Piezoelectric Laminates

2020

In this work, a novel high-order formulation for multilayered piezoelectric plates based on the combination of variable-order interior penalty discontinuous Galerkin methods and general layer-wise plate theories is presented, implemented and tested. The key feature of the formulation is the possibility to tune the order of the basis functions in both the in-plane approximation and the through-the-thickness expansion of the primary variables, namely displacements and electric potential. The results obtained from the application to the considered test cases show accuracy and robustness, thus confirming the developed technique as a supplementary computational tool for the analysis and design o…

Intra-individual variability in task performance after cognitive training is associated with long-term outcomes in children

2020

AbstractThe benefits and mechanistic effects of working memory training in children are the subject of much research and debate. The cumulative evidence indicates that training can alter brain structure and function in the short term and have lasting effects on behaviour. We show that five weeks of working memory training led to greater activity in prefrontal and striatal brain regions, better accuracy, and reduced intra-individual variability in response times. The reduction in intra-individual variability can be explained by changes to the evidence accumulation rates and thresholds in a sequential sampling decision model. Critically, intra-individual variability was more closely associate…

La inhibición, el autocontrol emocional, la memoria de trabajo y la supervisión ¿predicen las manifestaciones típicas de adultos con TDAH?

2019

Introducción. Los déficits en inhibición, control emocional, memoria de trabajo y supervisión se han evidenciado en numerosas investigaciones focalizadas en el trastorno por déficit de atención con hiperactividad (TDAH), pero la información sobre su posible influencia diferencial en las manifestaciones características del trastorno es escasa. Objetivos. El presente estudio se propuso analizar las relaciones de las funciones ejecutivas de regulación (inhibición y control emocional) y metacognitivas (memoria de trabajo y supervisión) con manifestaciones del TDAH y determinar el poder de predicción de esas cuatro funciones ejecutivas en dichas manifestaciones. Método. Sesenta y un jóvenes adul…

RELIABILITY AND VALIDITY OF THE LATVIAN VERSION OF THE COMPUTERIZED EXECUTIVE FUNCTIONS TEST “EXAMINER” IN A STUDENTS SAMPLE: RESULTS OF THE PILOT ST…

2016

The aim of this pilot-study was to assess reliability and validity of the Latvian version of the computerized executive functions test EXAMINER (Executive Abilities: Measures and Instruments for Neurobehavioral Evaluation and Research) in a sample of high school students and university students. The adaptation procedure included translation of the instructions and technical configuration of the test’s computerized version. The Latvian version of the EXAMINER includes tasks that measure executive functions of inhibition, set shifting and working memory updating. Participants included two sub-groups: 22 (14 males, 8 female) students from high school and 39 students (11 males, 28 female) from …

2020

Physical activity and exercise beneficially link to brain properties and cognitive functions in older adults, but the findings concerning adolescents remain tentative. During adolescence, the brain ...