Rothberger's property in all finite powers

A space X has the Rothberger property in all finite powers if, and only if, its collection of ω-covers has Ramseyan properties.     

Temperature dependent band gap shrinkage in GaN: Role of electron–phonon interaction

We present an experimental investigation of temperature dependent band-gap shrinkage in GaN using photoluminescence spectroscopy. The near-band-edge transition energy shifts to lower energy with increasing temperature. The parameters that describe the temperature-dependent red-shift of the band-edge transition energy are evaluated using different models. It has been found that the semi-empirical relation based on phonon-dispersion related spectral function leads to an excellent fit to the experimental data.     

Reduction of false alarms in forest fire surveillance using water vapour concentration measurements

In this work a theoretical model to evaluate the capabilities of our lidar system in forest fire detection is reported. In particular, a new idea of minimization of false alarm is shown. In a forest fire, in fact, a lot of ashes and in the first stage a large amount of water vapour are emitted. Measurements of water vapour increase with respect to standard humidity in the atmosphere due to a forest fire event, by means of Raman analysis, permit to minimize the false alarm. A simulation of one case of study permits to estimate the maximum range of detection and minimum sensibility of our lidar system. In this paper the theoretical results are shown.     

Assessing gender and top-management-team pay in the S&P Mid-Cap and Small-Cap companies using data envelopment analysis

In this study, we use data envelopment analysis (DEA) to study gender equity in top-management-team compensation in the S&P Mid-Cap and Small-Cap companies. We find that female and male executives in these companies receive comparable compensation when controlling for differences in company performance, company size, and company pay philosophy.     

Kernel based quadrature on spheres and other homogeneous spaces

Quadrature formulas for spheres, the rotation group, and other compact, homogeneous manifolds are important in a number of applications and have been the subject of recent research. The main purpose of this paper is to study coordinate independent quadrature (or cubature) formulas associated with certain classes of positive definite and conditionally positive definite kernels that are invariant under the group action of the homogeneous manifold. In particular, we show that these formulas are accurate—optimally so in many cases—and stable under an increasing number of nodes and in the presence of noise, provided the set $X$ of quadrature nodes is quasi-uniform. The stability results are new in all cases. In addition, we may use these quadrature formulas to obtain similar formulas for manifolds diffeomorphic to $\mathbb S ^n$ , oblate spheroids for instance. The weights are obtained by solving a single linear system. For $\mathbb S ^2$ , and the restricted thin plate spline kernel $r^2\log r$ , these weights can be computed for two-thirds of a million nodes, using a preconditioned iterative technique introduced by us.     

I Just Don't Trust Them: The Development and Validation of an Assessment Instrument to Measure Trust in Science and Scientists

Trust in science and scientists can greatly influence consideration of scientific developments and activities. Yet, trust is a nebulous construct based on emotions, knowledge, beliefs, and relationships. As we explored the literature regarding trust in science and scientists we discovered that no instruments were available to assess the construct, and therefore, we developed one. Using a process of data collection from science faculty members and undergraduate students, field testing, expert feedback, and an iterative process of design, we developed, validated, and established the reliability of the Trust in Science and Scientist Inventory. Our 21‐item instrument has a reliability of Cronbach's alpha of .86, and we have successfully field‐tested it with a range of undergraduate college students. We discuss implications and possible applications of the instrument, and include it in the appendix.     

Homogenization of random anisotropy properties in polycrystalline magnetic materials

This paper is devoted to the determination of the equivalent anisotropy properties of polycrystalline magnetic materials, modelled by an assembly of monocrystalline grains with a stochastic spatial distribution of easy axes. The mathematical theory of $\Gamma \text{-}\mathrm{convergence}$ is applied to homogenize the anisotropic term in the Gibbs free energy. The procedure is validated focusing on the micromagnetic computation of reversal processes in polycrystalline magnetic thin films.     

Combinatorics of open covers (XI): Menger- and Rothberger-bounded groups

We examine Menger-bounded (=o-bounded) and Rothberger-bounded groups. We give internal characterizations of groups having these properties in all finite powers (Theorems 6 and 7, and Theorem 15). In the metrizable case we also give characterizations in terms of measure-theoretic properties relative to left-invariant metrics (Theorems 12 and 19). Among metrizable σ-totally bounded groups we characterize the Rothberger-bounded groups by the corresponding game (Theorem 22).     

Oxygen ion conductors for fuel cells and membranes: selected developments

Recent developments on single-phase and composite materials with oxygen ionic conductivity are briefly reviewed. Attention is focused on electrolytes with apatite-like structure, yttria-stabilized zirconia (YSZ) ceramics containing silica and apatite admixtures, and composite mixed conductors where chemical interaction of the components is large or severely constrained. The results show, in particular, a key role of phase interaction and microstructural design on materials performance. The ideas behind the adopted procedures can be extended to other systems and combinations of properties based on thermodynamic equilibria information.     

Spectroscopic, Chromatographic and Visual Investigation of Organic Dyes

An introductory level laboratory experiment is presented in which students learn about color using spectroscopy and chromatography. The pedagogical approach is discovery-based; students are given only enough background information to enable them to take good data. Commercially available dyes are dissolved in water to make concentrated stock solutions, which students then dilute to prepare solutions of primary, secondary and tertiary colors. The class works as a team to study colored solutions representing a range of concentrations and combinations of the three primary colors: cyan, yellow, and magenta. Students record transmission and absorption spectra and compare the results with human perception. They show the number of components in each solution by paper chromatography. They explore the filter nature of dyes, the effects of concentration, and the cumulative effects of mixing dyes. From this information they deduce the principles of color printing.The experiment is best performed with a photodiode array spectrophotometer; alternative approaches include spectrometers and simple spectroscopes which the students make from cereal boxes. The experiment can be performed in either a single three-hour laboratory period, or alternatively, three one-hour sessions.