Photoassociative ionization of Na inside a storage ring

Motivated by recent interest in low dimensional arrays of atoms, we experimentally investigated the way cold collisional processes are affected by the geometry of the considered atomic sample. More specifically, we studied the case of photoassociative ionization (PAI) both in a storage ring where collision is more unidirectional in character and in a trap with clear undefinition of collision axis. First, creating a ring shaped trap (atomotron) we investigated two-color PAI dependence with intensity and polarization of a probing laser. The intensity dependence of the PAI rate was also measured in a magneto-optical trap presenting equivalent temperature and density conditions. Indeed, the results show that in the ring trap, the value of the PAI rate constant is much lower and does not show evidences of saturation, unlike in the case of the 3D-MOT. Cold atomic collisions in storage ring may represent new possibilities for study.Comment: 5 pages, 5 figures; Accepted by Optics Communicatio

Accessibility analysis of higher education institution websites of Portugal

The higher education institutions across the globe are steadily increasing their usage of the web platforms to disseminate information to its stakeholders. In this background, it becomes important to make these resources inclusive. An inclusive website of a higher education institution will facilitate seamless access to its resources for Persons with Disabilities (PwDs). This paper presents an accessibility analysis of 59 higher education websites of Portugal. Both Polytechnic (19) and University (40) websites were incorporated into the study.The accessibility analysis is carried out with three major tools: AChecker, WAVE, and aXe. With respect to the AChecker tool, the average of known problems was observed almost doubled in Universities than Polytechnic Institution websites of Portugal under all levels of conformance. With respect to WAVE tool, we found that the average of alerts, structural elements, and HTML5 & ARIA in terms of web accessibility status of websites of Polytechnic Institutes are less than the Universities, but contrast errors are found with more frequency in Polytechnic Institutes than in universities, and the average of errors and features are almost the same in both of the cases. Also, we found that the average number of violations and needs of review guidelines as per aXe tool are 50.84 and 21.47 in Polytechnic Institutes? websites and 30.75 and 27.83 in Universities websites belonging to Portugal, respectively. Based on scores obtained by these accessibility analysis tools, the outliers of accessibility violations are calculated with respect to websites of Polytechnic Institutes and Universities of Portugal. Moreover, we also suggested and discussed the important clues to solve the accessibility violations of websites along with their issue descriptions among the selected websites in this study. Hence, this analysis report provides the feedback to website administrator and web developers to improve the accessibility evaluation status of these websites.5311-8814-F0ED | Sara Maria da Cruz Maia de Oliveira PaivaN/

s-wave Superconductivity Phase Diagram in the Inhomogeneous Two-Dimensional Attractive Hubbard Model

We study s-wave superconductivity in the two-dimensional square lattice attractive Hubbard Hamiltonian for various inhomogeneous patterns of interacting sites. Using the Bogoliubov-de Gennes (BdG) mean field approximation, we obtain the phase diagram for inhomogeneous patterns in which the on-site attractive interaction U_i between the electrons takes on two values, U_i=0 and -U/(1-f) (with f the concentration of non-interacting sites) as a function of average electron occupation per site n, and study the evolution of the phase diagram as f varies. In certain regions of the phase diagram, inhomogeneity results in a larger zero temperature average pairing amplitude (order parameter) and also a higher superconducting (SC) critical temperature T_c, relative to a uniform system with the same mean interaction strength (U_i=-U on all sites). These effects are observed for stripes, checkerboard, and even random patterns of the attractive centers, suggesting that the pattern of inhomogeneity is unimportant. The phase diagrams also include regions where superconductivity is obliterated due to the formation of various charge ordered phases. The enhancement of T_{c} due to inhomogeneity is robust as long as the electron doping per site n is less than twice the fraction of interacting sites [2(1-f)] regardless of the pattern. We also show that for certain inhomogeneous patterns, when n = 2(1-f), increasing temperature can work against the stability of existing charge ordered phases for large f and as a result, enhance T_{c}.Comment: 16 pages, 11 figure

Ab initio study on the magneto-structural properties of MnAs

The magnetic and structural properties of MnAs are studied with ab initio methods, and by mapping total energies onto a Heisenberg model. The stability of the different phases is found to depend mainly on the volume and on the amount of magnetic order, confirming previous experimental findings and phenomenological models. It is generally found that for large lattice constants the ferromagnetic state is favored, whereas for small lattice constants different antiferromagnetic states can be stabilized. In the ferromagnetic state the structure with minimal energy is always hexagonal, whereas it becomes orthorhombically distorted if there is an antiferromagnetic component in the hexagonal plane. For the paramagnetic state the stable cell is found to be orthorhombic up to a critical lattice constant of about 3.7 Angstrom, above which it remains hexagonal. This leads to the second order structural phase transition between paramagnetic states at about 400 K, where the lattice parameter increases above this critical value with rising temperature due to the thermal expansion. For the paramagnetic state an analytic approximation for the magnitude of the orthorhombic distortion as a function of the lattice constant is given. Within the mean field approximation the dependence of the Curie temperature on the volume and on the orthorhombic distortion is calculated. For orthorhombically distorted cells the Curie temperature is much smaller than for hexagonal cells. This is mainly due to the fact that some of the exchange coupling constants in the hexagonal plane become negative for distorted cells. With these results a description of the susceptibility as function of temperature is given

Investigação de parâmetros de inflamação e estresse oxidativo em pacientes com diabetes mellitus tipo 2 usuários e não usuários de insulinoterapia

Considerando que a DM representa, atualmente, um dos problemas mais significativos de saúde pública, e ainda que a DM2, corresponde a mais de 90% dos casos de diabetes no mundo, e está associada ao aumento do risco de complicações micro e macrovasculares, torna-se importante a avaliação laboratorial de marcadores de inflamação, estresse oxidativo e hemostasia em pacientes com Diabetes Mellitus tipo 2. Trata-se de um estudo clínico onde serão selecionados 120 pacientes diagnosticados com DM2 (40 em utilização de insulina e 40 sem utilização de insulina) e 40 pacientes controle (sem diagnóstico de DM2), vinculados às equipes de Unidade de Saúde da Família (USF) do território de Consolação. O controle metabólico será avaliado através dos exames de glicemia de jejum, hemoglobina glicada (A1C), perfil lipídico e proteína C reativa ultrassensível. O estresse oxidativo será monitorado através dos níveis de óxido nítrico usando a reação de Griess, da avaliação da peroxidação lipídica com a técnica do ácido tiobarbitúrico e da atividade da superóxido dismutase. A avaliação da hemostasia será realizada através de marcadores específicos: fibrinogênio, dímero D (D-Di) e inibidor do ativador do plasminogênio (PAI-1), e da investigação dos polimorfismos -675 4G/5G na região promotora do gene do PAI-1. E a avaliação da inflamação será realizada através da dosagem dos níveis de IL-1β e TNF- α. Considerando a progressão e gravidade da doença no Brasil e no mundo, espera-se conhecer as características da doença e do tratamento dos pacientes com DM2, cadastrados da Unidade de Saúde da Família (USF) do território Consolação; e contribuir para elucidação de mecanismos metabólicos, inflamatórios, hemostáticos e de estresse oxidativo nestes pacientes, uma vez que os mecanismos patogênicos da doença ainda não estão totalmente esclarecidos. Palavras chave: diabetes mellitus tipo 2, controle metabólico, inflamação, estresse oxidativo, hemostasi

Effect of inhomogeneity on s-wave superconductivity in the attractive Hubbard model

Inhomogeneous s-wave superconductivity is studied in the two-dimensional, square lattice attractive Hubbard Hamiltonian using the Bogoliubov-de Gennes (BdG) mean field approximation. We find that at weak coupling, and for densities mainly below half-filling, an inhomogeneous interaction in which the on-site interaction $U_i$ takes on two values, $U_i=0, 2U$ results in a larger zero temperature pairing amplitude, and that the superconducting $T_c$ can also be significantly increased, relative to a uniform system with $U_i=U$ on all sites. These effects are observed for stripe, checkerboard, and even random patterns of the attractive centers, suggesting that the pattern of inhomogeneity is unimportant. Monte Carlo calculations which reintroduce some of the fluctuations neglected within the BdG approach see the same effect, both for the attractive Hubbard model and a Hamiltonian with d-wave pairing symmetry.Comment: 5 pages, 4 figure

A layering model for superconductivity in the borocarbides

We propose a superlattice model to describe superconductivity in layered materials, such as the borocarbide families with the chemical formul\ae\ $RT_2$B$_2$C and $RT$BC, with $R$ being (essentially) a rare earth, and $T$ a transition metal. We assume a single band in which electrons feel a local attractive interaction (negative Hubbard-$U$) on sites representing the $T$B layers, while U=0 on sites representing the $R$C layers; the multi-band structure is taken into account minimally through a band offset $\epsilon$. The one-dimensional model is studied numerically through the calculation of the charge gap, the Drude weight, and of the pairing correlation function. A comparison with the available information on the nature of the electronic ground state (metallic or superconducting) indicates that the model provides a systematic parametrization of the whole borocarbide family.Comment: 4 figure

Upper Extremity Motor Learning among Individuals with Parkinson's Disease: A Meta-Analysis Evaluating Movement Time in Simple Tasks

Motor learning has been found to occur in the rehabilitation of individuals with Parkinson's disease (PD). Through repetitive structured practice of motor tasks, individuals show improved performance, confirming that motor learning has probably taken place. Although a number of studies have been completed evaluating motor learning in people with PD, the sample sizes were small and the improvements were variable. The purpose of this meta-analysis was to determine the ability of people with PD to learn motor tasks. Studies which measured movement time in upper extremity reaching tasks and met the inclusion criteria were included in the analysis. Results of the meta-analysis indicated that people with PD and neurologically healthy controls both demonstrated motor learning, characterized by a decrease in movement time during upper extremity movements. Movement time improvements were greater in the control group than in individuals with PD. These results support the findings that the practice of upper extremity reaching tasks is beneficial in reducing movement time in persons with PD and has important implications for rehabilitation

Competition between local potentials and attractive particle-particle interactions in superlattices

Naturally occuring or man-made systems displaying periodic spatial modulations of their properties on a nanoscale constitute superlattices. Such modulated structures are important both as prototypes of simple nanotechnological devices and as particular examples of emerging spatial inhomogeneity in interacting many-electron systems. Here we investigate the effect different types of modulation of the system parameters have on the ground-state energy and the charge-density distribution of the system. The superlattices are described by the inhomogeneous attractive Hubbard model, and the calculations are performed by density-functional and density-matrix renormalization group techniques. We find that modulations in local electric potentials are much more effective in shaping the system's properties than modulations in the attractive on-site interaction. This is the same conclusions we previously (Phys. Rev. B 71, 125130) obtained for repulsive interactions, suggesting that it is not an artifact of a specific state, but a general property of modulated structures.Comment: 8 pages, 2 figure

The 2020 IDS release of the Antwerp COR*-database. Evaluation, development and transformation of a pre-existing database

The Antwerp COR*-IDS database 2020 is a transformed and harmonized historical demographic database in a cross-nationally comparable format designed to be open and easy to use for international researchers. The database is constructed from the 2010 release of the Antwerp COR*-historical demographic database, which was created using a letter sample of the whole district of Antwerp (Flanders, Belgium). It has a total sample size of +/- 33,000 residents of Antwerp. The sample spans nearly seven decades. The data is collected from historical records: including population registers and vital registration records covering births, marriages, in/external migrations and deaths. The database covers up to three linked generations (in some cases more), and contains micro-data on individual level life courses, and relationships deriving from addressbased household composition methods. An important characteristic is the sample's large migrant population, including the timings of their demographic events and living arrangements, whilst resident in the district of Antwerp. In addition, the sample also contains a large array of occupational level information. This paper presents the processes, methodologies and documentation regarding the evaluation and development of a pre-existing historical database. This includes the systematic evaluation of the original samples, methodologies for address based reconstructing of households, and the geocoding of a historical database which took place during the current development of this new version of the database.info:eu-repo/semantics/publishedVersio