A Dimensional study of Disk Galaxies

We present a highly simplified model of the dynamical structure of a disk galaxy where only two parameters fully determine the solution, mass and angular momentum. We show through simple physical scalings that once the mass has been fixed, the angular momentum parameter $\lambda$ is expected to regulate such critical galactic disk properties as colour, thickness of the disk and disk to bulge ratio. It is hence expected to be the determinant physical ingredient resulting in a given Hubble type. A simple analytic estimate of $\lambda$ for an observed system is provided. An explicit comparison of the distribution of several galactic parameters against both Hubble type and $\lambda$ is performed using observed galaxies. Both such distributions exhibit highly similar characteristics for all galactic properties studied, suggesting $\lambda$ as a physically motivated classification parameter for disk galaxies.Comment: 10 pages including 11 figures, Final version, MNRAS in pres

The Challenge of Integrating Faith-Learning-Living in Teacher Education

Teacher educators from member institutions of the Coalition for Christian Colleges and Universities are currently challenged in an unprecedented way. The challenge is to satisfy increasingly rigorous state and national teacher education standards and to fulfill the commonly held mission of Coalition institutions to integrate faith-learning-living. The research presented in this article traces the long history of integration and presents various theoretical integration models commonly supported by educators at Christian colleges and universities. This article suggests meeting the challenge in part through an original six component integration model with potential value for Christian educators representing various academic disciplines

Circumstellar effects on the Rb abundances in O-rich AGB stars

For the first time we explore the circumstellar effects on the Rb (and Zr) abundance determination in O-rich asymptotic giant branch (AGB) stars by considering the presence of a gaseous circumstellar envelope with a radial wind. A modified version of the spectral synthesis code Turbospectrum was used to deal with extended atmosphere models and velocity fields. The Rb and Zr abundances were determined from the resonant 7800A Rb I line and the 6474A ZrO bandhead, respectively, in five representative O-rich AGB stars with different expansion velocity and metallicity. By using our new dynamical models, the Rb I line profile (photospheric and circumstellar components) is very well reproduced. Interestingly, the derived Rb abundances are much lower (by 1-2 dex) in those O-rich AGB stars showing the higher circumstellar expansion velocities. The Zr abundances, however, remain close to the solar values. The Rb abundances and Rb/Zr ratios derived here significantly alleviate the problem of the present mismatch between the observations of intermediate-mass (4-8 solar masses) Rb-rich AGB stars and the AGB nucleosynthesis theoretical predictions.Comment: Accepted for publication in Astronomy & Astrophysics Letters (7 pages, 5 figures, and 2 tables); final version (language corrected

Private Electronic Money, Fiat Money and the Payments System

This paper provides insight on how a modern system of private electronic money would work and how the necessary network shall function. We present a model with two types of private electronic currencies with one being local, and the other being global. Both of them display transactional advantages and dominate fiat money in rate of return. However, in spite of these different returns, the two electronic currencies and fiat money circulate in equilibrium. We further observe that the local electronic currency can be sold with a premium or with a discount, depending on several factors including the probability of relocation faced by the agents in this economy. The higher the probability of relocation, the higher is this discount, and the lower the share of the local electronic currency in the young creditors’ portfolio.Private Money, Commodity Money, Network, Payments System, Competition

A linear filter to reconstruct the ISW effect from CMB and LSS observations

The extraction of a signal from some observational data sets that contain different contaminant emissions, often at a greater level than the signal itself, is a common problem in Astrophysics and Cosmology. The signal can be recovered, for instance, using a simple Wiener filter. However, in certain cases, additional information may also be available, such as a second observation which correlates to a certain level with the sought signal. In order to improve the quality of the reconstruction, it would be useful to include as well this additional information. Under these circumstances, we have constructed a linear filter, the linear covariance-based filter, that extracts the signal from the data but takes also into account the correlation with the second observation. To illustrate the performance of the method, we present a simple application to reconstruct the so-called Integrated Sachs-Wolfe effect from simulated observations of the Cosmic Microwave Background and of catalogues of galaxies.Comment: 8 pages, 6 figures, accepted for publication in the IEEE Journal of Selected Topics in Signal Processin

Design-thinking, making, and innovating: Fresh tools for the physician\u27s toolbox

Medical school education should foster creativity by enabling students to become \u27makers\u27 who prototype and design. Healthcare professionals and students experience pain points on a daily basis, but are not given the tools, training, or opportunity to help solve them in new, potentially better ways. The student physician of the future will learn these skills through collaborative workshops and having dedicated \u27innovation time.\u27 This pre-clinical curriculum would incorporate skills centered on (1) Digital Technology and Small Electronics (DTSE), (2) Textiles and Medical Materials (TMM), and (3) Rapid Prototyping Technologies (RPT). Complemented by an on-campus makerspace, students will be able to prototype and iterate on their ideas in a fun and accessible space. Designing and making among and between patients and healthcare professionals would change the current dynamic of medical education, empowering students to solve problems in healthcare even at an early stage in their career. By doing so, they will gain empathy, problem-solving abilities, and communication skills that will extend into clinical practice. Our proposed curriculum will equip medical students with the skills, passion, and curiosity to impact the future of healthcare

Effect of tail-fin span on stability and control characteristics of a Canard-controlled missile at supersonic Mach numbers

An experimental wind-tunnel investigation was conducted at Mach numbers from 1.60 to 3.50 to obtain the longitudinal and lateral-directional aerodynamic characteristics of a circular, cruciform, canard-controlled missile with variations in tail-fin span. In addition, comparisons were made with the experimental aerodynamic characteristics using three missile aeroprediction programs: MISSILE1, MISSILE2, and NSWCDM. The results of the investigation indicate that for the test Mach number range, canard roll control at low angles of attack is feasible on tail-fin configurations with tail-to-canard span ratios of less than or equal to 0.75. The conards are effective pitch and yaw control devices on each tail-fin span configuration tested. Programs MISSILE1 and MISSILE2 provide very good predictions of longitudinal aerodynamic characteristics and fair predictions of lateral-directional aerodynamic characteristics at low angles of attack, with MISSILE2 predictions generally in better agreement with test data. Program NSWCDM provides good longitudinal and lateral-directional aerodynamic predictions that improve with increases in tail-tin span