Valuing voluntary disclosure using a real options approach

This paper outlines a real options approach to valuing those announcements which are made by firms outside of their legal requirements. From the firm's perspective, information is disclosed only if the manager of the firm is sufficiently certain that the market response to the announcement will have a positive impact on the value of the firm. When debt financing is possible we find that the manager adopts a more transparent disclosure policy, thus violating the Modigliani-Miller theorem on irrelevance of capital structure

The effect of high school rank in English and math on college major choice. ESRI Working Paper No. 650 January 2020

Using unique data on preference rankings for all high school students who apply for college in Ireland, we investigate whether, conditional on absolute achievement, within school-cohort rank in English and math affects choice of college major. We find that higher rank in math increases the likelihood of choosing STEM and decreases the likelihood of choosing Arts and Social Sciences. Similarly, a higher rank in English leads to an increase in the probability of choosing Arts and Social Sciences and decreases the probability of choosing STEM. The rank effects are substantial, being about one third as large as the effects of absolute performance in math and English. We identify subject choice in school as an important mediator – students who rank high in math are more likely to choose STEM subjects in school and this can partly explain their subsequent higher likelihood of choosing STEM for college. We also find that English and math rank have significant explanatory power for the gender gap in the choice of STEM as a college major--they can explain about 36% as much as absolute performance in English and math. Overall, the tendency for girls to be higher ranked in English and lower ranked in math within school-cohorts can explain about 6% of the STEM gender gap in mixedsex schools and about 16% of the difference in the STEM gender gap between mixedsex schools and same-sex schools. Notably, these effects occur even though within-school rank plays no role whatsoever in college admissions decisions

Learning to do, doing to learn: an exploration of teacher knowledge and learning through the narratives of trainees on a CELTA (Cambridge English Certificate in Teaching English to Speakers of Other Languages) course

It is a widely held view that theory and practice are the two core elements of a teacher’s knowledge. What is less defined is how the two interact during the process by which teachers learn to be teachers and whether a case should be made for one being more important than the other. Academics have sometimes queried the notion of practice being a part of knowledge because of the difficulty of quantifying it in a tangible manner. Instead knowledge constructs that are theory based are preferred. The practice of asking participants on a teacher education course to reflect critically on their classroom actions is often used to generate theoretical knowledge from the practical. In my research I examine the nature of teacher knowledge from the perspective of participants on a teacher education course using interviews and email correspondence over the duration of the course and up to one year afterwards. I also explore the views of the researcher as teacher educator through a research artefact or scrapbook. From the data collected it seems that teachers undergo a continuous process of theory making from their practical experience and value this self-generated “practice theory” as the most important constituent of teacher knowledge. Their declarative knowledge is a way of acting in the classroom, but it goes beyond simple replication of actions they observe or are instructed to perform. A “practice theory” is constructed from moments of practice which are congruent with pre-formed views of teaching from their experience as learners and is validated by their personal constructs of success, including the response of their own learners. In looking at how teachers gain this knowledge, this thesis questions the paradigm of co-operative social learning which is often assumed to exist on teacher education programmes. Data suggests that course participants act as individuals seeking to survive a difficult process and exhibit a loyalty to their peers which renders the learning relationship with tutors less benign than is often assumed. This in turn calls into question the acceptance of critical reflection as a key part of teacher learning. The thesis also examines processes which are common to teacher education programmes such as observation and structured practice, and proposes that learning teachers’ experience sometimes contradicts what is often assumed to be good practice. The thesis highlights some considerations for teacher educators. It proposes an increased valuing of the practical and the existence of a practice theory, one that can provide knowledge constructs for teachers. In addition, it suggests a refocus for some activities on teacher education courses to make them more congruent with the real experiences of trainees

The First Measurement of Cassiopeia A's Forward Shock Expansion Rate

We have obtained a second epoch observation of the Cassiopeia A supernova remnant (SNR) with the Chandra X-ray Observatory to measure detailed X-ray proper motions for the first time. Both epoch observations are 50 ks exposures of the ACIS-S3 chip and they are separated by 2 years. Measurements of the thin X-ray continuum dominated filaments located around the edge of the remnant (that are identified with the forward shock) show expansion rates from 0.02%/yr to 0.33%/yr. Many of these filaments are therefore significantly decelerated. Their median value of 0.21%/yr is equal to the median expansion of the bright ring (0.21%/yr) as measured with Einstein and ROSAT. This presents a conundrum if the motion of the bright ring is indicative of the reverse shock speed. We have also re-evaluated the motion of the radio bright ring with emphasis on angle-averaged emissivity profiles. Our new measurement of the expansion of the angle-averaged radio bright ring is 0.07 plus or minus 0.03%/yr, somewhat slower than the previous radio measurements of 0.11%/yr which were sensitive to the motions of small-scale features. We propose that the expansion of the small-scale bright ring features in the optical, X-ray, and radio do not represent the expansion of the reverse shock, but rather represent a brightness-weighted average of ejecta passing through and being decelerated by the reverse shock. The motion of the reverse shock, itself, is then represented by the motion of the angle-averaged emissivity profile of the radio bright ring.Comment: accepted to Ap

Comment on "Electron transport through correlated molecules computed using the time-independent Wigner function: Two critical tests"

The many electron correlated scattering (MECS) approach to quantum electronic transport was investigated in the linear response regime [I. Baldea and H. Koeppel, Phys. Rev. B. 78, 115315 (2008)]. The authors suggest, based on numerical calculations, that the manner in which the method imposes boundary conditions is unable to reproduce the well-known phenomena of conductance quantization. We introduce an analytical model and demonstrate that conductance quantization is correctly obtained using open system boundary conditions within the MECS approach.Comment: 18 pages, 4 figures. Physical Review B, to appea

Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 4: Advanced fan section aerodynamic analysis

The purpose of this study is the development of a three-dimensional Euler/Navier-Stokes flow analysis for fan section/engine geometries containing multiple blade rows and multiple spanwise flow splitters. An existing procedure developed by Dr. J. J. Adamczyk and associates and the NASA Lewis Research Center was modified to accept multiple spanwise splitter geometries and simulate engine core conditions. The procedure was also modified to allow coarse parallelization of the solution algorithm. This document is a final report outlining the development and techniques used in the procedure. The numerical solution is based upon a finite volume technique with a four stage Runge-Kutta time marching procedure. Numerical dissipation is used to gain solution stability but is reduced in viscous dominated flow regions. Local time stepping and implicit residual smoothing are used to increase the rate of convergence. Multiple blade row solutions are based upon the average-passage system of equations. The numerical solutions are performed on an H-type grid system, with meshes being generated by the system (TIGG3D) developed earlier under this contract. The grid generation scheme meets the average-passage requirement of maintaining a common axisymmetric mesh for each blade row grid. The analysis was run on several geometry configurations ranging from one to five blade rows and from one to four radial flow splitters. Pure internal flow solutions were obtained as well as solutions with flow about the cowl/nacelle and various engine core flow conditions. The efficiency of the solution procedure was shown to be the same as the original analysis

Investigation of Advanced Counterrotation Blade Configuration Concepts for High Speed Turboprop Systems. Task 3: Advanced Fan Section Grid Generator Final Report and Computer Program User's Manual

A procedure is studied for generating three-dimensional grids for advanced turbofan engine fan section geometries. The procedure constructs a discrete mesh about engine sections containing the fan stage, an arbitrary number of axisymmetric radial flow splitters, a booster stage, and a bifurcated core/bypass flow duct with guide vanes. The mesh is an h-type grid system, the points being distributed with a transfinite interpolation scheme with axial and radial spacing being user specified. Elliptic smoothing of the grid in the meridional plane is a post-process option. The grid generation scheme is consistent with aerodynamic analyses utilizing the average-passage equation system developed by Dr. John Adamczyk of NASA Lewis. This flow solution scheme requires a series of blade specific grids each having a common axisymmetric mesh, but varying in the circumferential direction according to the geometry of the specific blade row

Data processing system for the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory-F (OGO-F) satellite

The system is discussed which was developed to process digitized telemetry data from the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory (OGO-F) Satellite. Functional descriptions and operating instructions are included for each program in the system