The relation between college student involvement and satisfaction

The purpose of this study was to examine the relation between college students\u27 involvement and their overall satisfaction with their college experience. It was predicted that the more a student is involved, the more he/she will be satisfied with the college experience. The 60 male and female respondents were traditional students at Anderson University in Anderson, SC. A survey was administered to assess student involvement based on the diversity (types of activities) and amount (hours per week) of participation. Each student\u27s satisfaction with college also was assessed using a self-devised scale. A moderate positive correlation was detected, p\u3c.01, where 12% of the variance in student satisfaction was accounted for by student involvement. The implications and limitations are discussed

Parametrizations of density matrices

This article gives a brief overview of some recent progress in the characterization and parametrization of density matrices of finite dimensional systems. We discuss in some detail the Bloch-vector and Jarlskog parametrizations and mention briefly the coset parametrization. As applications of the Bloch parametrization we discuss the trace invariants for the case of time dependent Hamiltonians and in some detail the dynamics of three-level systems. Furthermore, the Bloch vector of two-qubit systems as well as the use of the polarization operator basis is indicated. As the main application of the Jarlskog parametrization we construct density matrices for composite systems. In addition, some recent related articles are mentioned without further discussion.Comment: 31 pages. v2: 32 pages, Abstract and Introduction rewritten and Conclusion section added, references adde

Band structure model of magnetic coupling in semiconductors

We present a unified band structure model to explain magnetic ordering in Mn-doped semiconductors. This model is based on the $p$-$d$ and $d$-$d$ level repulsions between the Mn ions and host elements and can successfully explain magnetic ordering observed in all Mn doped II-VI and III-V semiconductors such as CdTe, GaAs, ZnO, and GaN. This model, therefore, provides a simple guideline for future band structure engineering of magnetic semiconductors.Comment: 4+ pages, 5 figure

Contribuição adicional das imagens por tensores de difusão em paralisia do olhar conjugado horizontal associada a escoliose progressiva

In two siblings with clinical diagnosis of horizontal gaze palsy associated with progressive scoliosis (HGPPS) we could demonstrate by diffusion tensor imaging: (1) An anterior displacement of the transverse pontine fibers; (2) Posterior clumping of the corticospinal, medial lemniscus and central tegmental tracts and of the medial and dorsal longitudinal fasciculi complex; (3) Absent decussation of superior cerebellar peduncle. Those findings can contribute as surrogate markers for the diagnosis.Em dois irmãos com diagnóstico clínico de paralisia do olhar conjugado horizontal associada a escoliose progressiva, foi possível determinar através de imagens por tensores de difusão: (1) Deslocamento anterior das fibras pontinas transversas; (2) Agrupamento posterior do trato córtico-espinhal, lemnisco medial e trato tegmentar central e complexos dos fascículos longitudinais medial e dorsal; (3) Ausência da decussação dos pedúnculos cerebelares superiores. Tais achados podem contribuir como marcadores para o diagnóstico

Onsager's Inequality, the Landau-Feynman Ansatz and Superfluidity

We revisit an inequality due to Onsager, which states that the (quantum) liquid structure factor has an upper bound of the form (const.) x |k|, for not too large modulus of the wave vector k. This inequality implies the validity of the Landau criterion in the theory of superfluidity with a definite, nonzero critical velocity. We prove an auxiliary proposition for general Bose systems, together with which we arrive at a rigorous proof of the inequality for one of the very few soluble examples of an interacting Bose fluid, Girardeau's model. The latter proof demonstrates the importance of the thermodynamic limit of the structure factor, which must be taken initially at k different from 0. It also substantiates very well the heuristic density functional arguments, which are also shown to hold exactly in the limit of large wave-lengths. We also briefly discuss which features of the proof may be present in higher dimensions, as well as some open problems related to superfluidity of trapped gases.Comment: 28 pages, 2 figure, uses revtex

Spin separation in digital ferromagnetic heterostructures

In a study of the ferromagnetic phase of a multilayer digital ferromagnetic semiconductor in the mean-field and effective-mass approximations, we find the exchange interaction to have the dominant energy scale of the problem, effectively controlling the spatial distribution of the carrier spins in the digital ferromagnetic heterostructures. In the ferromagnetic phase, the majority and minority carriers tend to be in different regions of the space (spin separation). Hence, the charge distribution of carriers also changes noticeably from the ferromagnetic to the paramagnetic phase. An example of a design to exploit these phenomena is given.Comment: 4 pages, 3 figures. Submitted to Phys. Rev.

Observing System Simulation Experiment for a Multi-Angle Polarimeter

No abstract availabl

Electric Field Effects on Graphene Materials

Understanding the effect of electric fields on the physical and chemical properties of two-dimensional (2D) nanostructures is instrumental in the design of novel electronic and optoelectronic devices. Several of those properties are characterized in terms of the dielectric constant which play an important role on capacitance, conductivity, screening, dielectric losses and refractive index. Here we review our recent theoretical studies using density functional calculations including van der Waals interactions on two types of layered materials of similar two-dimensional molecular geometry but remarkably different electronic structures, that is, graphene and molybdenum disulphide (MoS$_2$). We focus on such two-dimensional crystals because of they complementary physical and chemical properties, and the appealing interest to incorporate them in the next generation of electronic and optoelectronic devices. We predict that the effective dielectric constant ($\varepsilon$) of few-layer graphene and MoS$_2$ is tunable by external electric fields ($E_{\rm ext}$). We show that at low fields ($E_{\rm ext}^{}<0.01$ V/\AA) $\varepsilon$ assumes a nearly constant value $\sim$4 for both materials, but increases at higher fields to values that depend on the layer thickness. The thicker the structure the stronger is the modulation of $\varepsilon$ with the electric field. Increasing of the external field perpendicular to the layer surface above a critical value can drive the systems to an unstable state where the layers are weakly coupled and can be easily separated. The observed dependence of $\varepsilon$ on the external field is due to charge polarization driven by the bias, which show several similar characteristics despite of the layer considered.Comment: Invited book chapter on Exotic Properties of Carbon Nanomatter: Advances in Physics and Chemistry, Springer Series on Carbon Materials. Editors: Mihai V. Putz and Ottorino Ori (11 pages, 4 figures, 30 references