On the Struggle To Attain Universal Competence in a Complex Skill: The Case of a Senior Capstone Experience

Seventeen years ago, a blue-ribbon committee of economists asserted that the “ideal” program for an economics major should include “a capstone experience, whereby students apply their knowledge and skills in creative and systematic ways through research and writing.” (Seigfried, Bartlett, Hansen, Kelley, McCloskey, and Tietenberg (1991)) Yet we are not aware of a data-driven assessment of an implemented senior capstone experience in the economics education literature. We have been experimenting with a senior capstone experience – based on research and writing – for more than a decade. In this paper we describe the history of our senior capstone experience, and provide a data-driven assessment of student performance in this experience. Our primary objective for this senior capstone has been to create a system that will result in all of our majors writing a competent senior thesis. In other words, we want to attain universal competence in a complex skill. This simple objective has, however, been very difficult to achieve. We will argue that undesired variation in student motivation has been our primary obstacle in attaining universal competence.

On the relation between sSFR and metallicity

In this paper we present an exact general analytic expression $Z(sSFR)=y/\Lambda(sSFR)+I(sSFR)$ linking the gas metallicity Z to the specific star formation rate (sSFR), that validates and extends the approximate relation put forward by Lilly et al. (2013, L13), where $y$ is the yield per stellar generation, $\Lambda(sSFR)$ is the instantaneous ratio between inflow and star formation rate expressed as a function of the sSFR, and $I$ is the integral of the past enrichment history, respectively. We then demonstrate that the instantaneous metallicity of a self-regulating system, such that its sSFR decreases with decreasing redshift, can be well approximated by the first term on the right-hand side in the above formula, which provides an upper bound to the metallicity. The metallicity is well approximated also by the L13 ideal regulator case, which provides a lower bound to the actual metallicity. We compare these approximate analytic formulae to numerical results and infer a discrepancy <0.1 dex in a range of metallicities and almost three orders of magnitude in the sSFR. We explore the consequences of the L13 model on the mass-weighted metallicity in the stellar component of the galaxies. We find that the stellar average metallicity lags 0.1-0.2 dex behind the gas-phase metallicity relation, in agreement with the data. (abridged)Comment: 14 pages, 6 figures, MNRAS accepte

Outsourcing the Human Resource Function: Environmental and Organizational Characteristics that Affect HR Performance

A theoretical model is presented that identifies environmental and organizational characteristics that affect human resource (HR) performance in an organization. Specifically, we address the issue of when and under what circumstances does HR outsourcing contribute value to the firm by attempting to identify environmental and organizational characteristics that affect HR department performance and how HR outsourcing mediates that relationship. We propose that supplier competition in the HR provider market has a direct effect on the amount of HR outsourcing which in turn has a direct effect on HR performance. Environmental uncertainty (primary, competitive, and supplier) is proposed to moderate the relationship between amount of HR outsourcing and HR performance while asset specificity is proposed to moderate the relationship between supplier competition and amount of HR outsourcing. An earlier version of this paper was presented at the Southwest Academy of Management meeting in Houston, Texas, March, 2003, and received the 2003 Irwin/McGraw-Hill Distinguished Paper Awar

Photo-z Performance for Precision Cosmology II : Empirical Verification

The success of future large scale weak lensing surveys will critically depend on the accurate estimation of photometric redshifts of very large samples of galaxies. This in turn depends on both the quality of the photometric data and the photo-z estimators. In a previous study, (Bordoloi et al. 2010) we focussed primarily on the impact of photometric quality on photo-z estimates and on the development of novel techniques to construct the N(z) of tomographic bins at the high level of precision required for precision cosmology, as well as the correction of issues such as imprecise corrections for Galactic reddening. We used the same set of templates to generate the simulated photometry as were then used in the photo-z code, thereby removing any effects of "template error". In this work we now include the effects of "template error" by generating simulated photometric data set from actual COSMOS photometry. We use the trick of simulating redder photometry of galaxies at higher redshifts by using a bluer set of passbands on low z galaxies with known redshifts. We find that "template error" is a rather small factor in photo-z performance, at the photometric precision and filter complement expected for all-sky surveys. With only a small sub-set of training galaxies with spectroscopic redshifts, it is in principle possible to construct tomographic redshift bins whose mean redshift is known, from photo-z alone, to the required accuracy of 0.002(1+z).Comment: 7 pages, 5 figures, accepted for publication in MNRA

Equine grass sickness : the geochemical connection

A new study uses the British Geological Survey’s geochemical map to investigate whether minerals in the environment are a factor in this predominantly fatal neurodegenerative disease of horse

Tunneling and nonlinear transport in a vertically coupled GaAs/AlGaAs double quantum wire system

We report low-dimensional tunneling in an independently contacted vertically coupled quantum wire system. This nanostructure is fabricated in a high quality GaAs/AlGaAs parallel double quantum well heterostructure. Using a novel flip chip technique to align top and bottom split gates to form low-dimensional constrictions in each of the independently contacted quantum wells we explicitly control the subband occupation of the individual wires. In addition to the expected 2D-2D tunneling results, we have found additional tunneling features that are related to the 1D quantum wires.Comment: 4 pages, 3 figures, submitted to APL Minor revision

Implementing Appropriate Use of Technology: A Case Study on How Rural Secondary Students Approach Digital Citizenship

The purpose of this intrinsic case study is to discover the approach of rural secondary students regarding their attainment and practice of digital citizenship in a learning environment that utilizes technology. The theory guiding this research study is Kohlberg’s theory of moral development as it emphasizes how individuals establish their ethics and values because digital citizenship teaches students to use the Internet in an ethical and appropriate manner. The qualitative inquiry was conducted using an intrinsic case study in a small rural secondary public school. Convenience sampling was utilized, giving way to 18 adolescent participants and 10 teachers at the school. All participants were well-versed in using technology. The data were obtained via semi-structured interviews with students and teachers, observations in classrooms, and an analysis of the Acceptable Use Policy. The collected data were analyzed, coded, and categorized into common themes pertaining to the research questions. The results indicated that digital citizenship is approached in multiple ways. The results also indicated that the participants expressed a correlation between one’s ethics and morals and their actions while using technology. The implications of the findings suggest that frequent instruction of digital citizenship occur and that students receive guidance on the use of proper ethics and morals when using technology. The implications also suggest that consequences and repercussions be explained to prevent inappropriate use of technology by adolescents

Undoped Electron-Hole Bilayers in a GaAs/AlGaAs Double Quantum Well

We present the fabrication details of completely undoped electron-hole bilayer devices in a GaAs/AlGaAs double quantum well heterostructure with a 30 nm barrier. These devices have independently tunable densities of the two-dimensional electron gas and two-dimensional hole gas. We report four-terminal transport measurements of the independently contacted electron and hole layers with balanced densities from $1.2 \times 10^{11}$cm$^{-2}$ down to $4 \times 10^{10}$ cm$^{-2}$ at $T = 300 mK$. The mobilities can exceed $1 \times 10^{6}$ cm$^{2}$ V$^{-1}$ s$^{-1}$ for electrons and $4 \times 10^{5}$ cm$^{2}$ V$^{-1}$ s$^{-1}$ for holes.Comment: 3 pages, 3 figure

Transplantation in children

Kidney transplantation in very young children, less than 2 years of age, has usually failed, mainly because of difficulties maintaining these patients on hemodialysis long enough to permit retransplantation after loss of the original graft. Liver replacement in the very young child has been associated with a higher frequency of vascular and biliary obstruction than in the older child, due to the small size of these structures. Such accidents have contributed to unsatisfactory results with biliary atresia. Transplantation of kidney or liver into older children has been more successful than transplantation of these organs into adults. Related or cadaveric kidney transplantation in the child has been followed by at least a 60 per cent patient survival for 6 to 13 years and a very acceptable quality of life. Liver replacement for diseases other than biliary atresia has been followed by a 56 per cent 1 year survival rate, and two children have survived for more than 5 years

Dynamical Domain Wall Defects in 2+1 Dimensions

We study some dynamical properties of a Dirac field in 2+1 dimensions with spacetime dependent domain wall defects. We show that the Callan and Harvey mechanism applies even to the case of defects of arbitrary shape, and in a general state of motion. The resulting chiral zero modes are localized on the worldsheet of the defect, an embedded curved two dimensional manifold. The dynamics of these zero modes is governed by the corresponding induced metric and spin connection. Using known results about determinants and anomalies for fermions on surfaces embedded in higher dimensional spacetimes, we show that the chiral anomaly for this two dimensional theory is responsible for the generation of a current along the defect. We derive the general expression for such a current in terms of the geometry of the defect, and show that it may be interpreted as due to an "inertial" electric field, which can be expressed entirely in terms of the spacetime curvature of the defects. We discuss the application of this framework to fermionic systems with defects in condensed matter.Comment: 12 pages, Late