Rare b and c Decays and the CKM Matrix

I report on developments in the experimental and phenomenological understanding of the rare decays of mesons containing b and c quarks, especially as they pertain to the understanding of the CKM matrix and the testing of the standard model. Some related measurements are also discussed.Comment: Talk given at "Physics in Collision," Cracow, June 10, 1995. 16 pages of self extracting, compressed, encoded postscrip

Hydrodynamic Coupling of Particle Inclusions Embedded in Curved Lipid Bilayer Membranes

We develop theory and computational methods to investigate particle inclusions embedded within curved lipid bilayer membranes. We consider the case of spherical lipid vesicles where inclusion particles are coupled through (i) intramembrane hydrodynamics, (ii) traction stresses with the external and trapped solvent fluid, and (iii) intermonolayer slip between the two leaflets of the bilayer. We investigate relative to flat membranes how the membrane curvature and topology augment hydrodynamic responses. We show how both the translational and rotational mobility of protein inclusions are effected by the membrane curvature, ratio of intramembrane viscosity to solvent viscosity, and inter-monolayer slip. For general investigations of many-particle dynamics, we also discuss how our approaches can be used to treat the collective diffusion and hydrodynamic coupling within spherical bilayers.Comment: 32 pages, double-column format, 15 figure

An Analysis of Cooperating Teacher Feedback: A Qualitative Inquiry

Cooperating teachers are a key component to the success of student teaching internships, serving an integral part in “raising” a teacher. To effectively facilitate the student teaching internship, teacher preparation programs must identify cooperating teachers who align philosophically with the pedagogical training delivered by university programs (Korthagen & Kessels, 1999; Tom, 1997), specifically, cooperating teachers who can reinforce the theoretical framework underpinning the professional coursework pre-service teachers experience in university teacher preparation programs. This qualitative study sought to better understand the feedback provided to future school-based agricultural education (SBAE) teachers during their student teaching experience. Through initial and secondary coding, the research team identified themes among the feedback provided to student teachers by their cooperating teachers. The study revealed cooperating teacher feedback reflects the pedagogical training provided via the teacher preparation program, specifically, around effective teaching behaviors. Understanding the cooperating teacher feedback provides insight for teacher preparation programs

Resolving transition metal chemical space: feature selection for machine learning and structure-property relationships

Machine learning (ML) of quantum mechanical properties shows promise for accelerating chemical discovery. For transition metal chemistry where accurate calculations are computationally costly and available training data sets are small, the molecular representation becomes a critical ingredient in ML model predictive accuracy. We introduce a series of revised autocorrelation functions (RACs) that encode relationships between the heuristic atomic properties (e.g., size, connectivity, and electronegativity) on a molecular graph. We alter the starting point, scope, and nature of the quantities evaluated in standard ACs to make these RACs amenable to inorganic chemistry. On an organic molecule set, we first demonstrate superior standard AC performance to other presently-available topological descriptors for ML model training, with mean unsigned errors (MUEs) for atomization energies on set-aside test molecules as low as 6 kcal/mol. For inorganic chemistry, our RACs yield 1 kcal/mol ML MUEs on set-aside test molecules in spin-state splitting in comparison to 15-20x higher errors from feature sets that encode whole-molecule structural information. Systematic feature selection methods including univariate filtering, recursive feature elimination, and direct optimization (e.g., random forest and LASSO) are compared. Random-forest- or LASSO-selected subsets 4-5x smaller than RAC-155 produce sub- to 1-kcal/mol spin-splitting MUEs, with good transferability to metal-ligand bond length prediction (0.004-5 {\AA} MUE) and redox potential on a smaller data set (0.2-0.3 eV MUE). Evaluation of feature selection results across property sets reveals the relative importance of local, electronic descriptors (e.g., electronegativity, atomic number) in spin-splitting and distal, steric effects in redox potential and bond lengths.Comment: 43 double spaced pages, 11 figures, 4 table

One Last Chance: The Economic Case for a New Approach to Fisheries Management in New England

Documents the decline of the New England fishing industry as a result of mismanagement, presents examples of successful and sustainable fisheries, and examines the viability of proposed community-based, fishermen-run cooperatives as a solution

Luminosity and surface brightness distribution of K-band galaxies from the UKIDSS Large Area Survey

We present luminosity and surface brightness distributions of 40,111 galaxies with K-band photometry from the United Kingdom Infrared Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS), Data Release 3 and optical photometry from Data Release 5 of the Sloan Digital Sky Survey (SDSS). Various features and limitations of the new UKIDSS data are examined, such as a problem affecting Petrosian magnitudes of extended sources. Selection limits in K- and r-band magnitude, K-band surface brightness and K-band radius are included explicitly in the 1/Vmax estimate of the space density and luminosity function. The bivariate brightness distribution in K-band absolute magnitude and surface brightness is presented and found to display a clear luminosity--surface brightness correlation that flattens at high luminosity and broadens at low luminosity, consistent with similar analyses at optical wavelengths. Best fitting Schechter function parameters for the K-band luminosity function are found to be M*-5 log h=-23.19 +/- 0.04, alpha=-0.81 +/- 0.04 and phi*=(0.0166 +/- 0.0008)h^3 Mpc^{-3}, although the Schechter function provides a poor fit to the data at high and low luminosity, while the luminosity density in the K band is found to be j = (6.305 +/- 0.067) x 10^8 L_sun h Mpc^{-3}. However, we caution that there are various known sources of incompleteness and uncertainty in our results. Using mass-to-light ratios determined from the optical colours we estimate the stellar mass function, finding good agreement with previous results. Possible improvements are discussed that could be implemented when extending this analysis to the full LAS.Comment: 17 pages, 24 figures, matches MNRAS accepted versio

Suspended Education in California

Analyzes data on risk of school suspension by race/ethnicity, gender, and disability status in nearly five hundred districts; highlights research showing suspensions to be ineffective and harmful; and calls for implementing evidence-based alternatives

Momentum and Contrarian Stock-Market Indices

We propose a new class of investable momentum and contrarian stock-market indices that partition a benchmark index, such as the Russell 1000. Our momentum indices overweight stocks that have recently outperformed, while our contrarian indices underweight these same stocks. Our index construction methodology is extremely flexible, and allows the index provider to trade-off the distinctiveness of the momentum/contrarian strategies with portfolio turnover. Momentum investment styles in particular typically entail a high level of turnover, and hence high associated transaction costs. The creation of momentum and contrarian indices and exchange traded funds (ETFs) based on our methodology would allow investors to access these styles at lower cost than is currently possible. Our indices also provide performance benchmarks for momentum/contrarian investment managers, and good proxies for a momentum factor. Over the period 1995- 2007 we find that short term momentum and long term contrarian indices outperform the reference Russell 1000 index. We also document the changing interaction between the momentum/contrarian and value/growth styles.Momentum index; Contrarian index; Performance measurement; Turnover; Momentum factor; Behavioral finance