An Evening of Grounded Theory: Teaching Process through Demonstration and Simulation

Grounded theory can be effectively introduced in a survey course through a combination of lecture/demonstration and simulation. The class session presented here illustrates a way to introduce graduate students to the process of grounded theory and gain hands-on experience through simulation. The lesson utilizes concepts that the students are familiar with, allowing them to focus on the research process, and encourages internalization of concepts through immediate application

Low-energy collisions of negative ions with atomic hydrogen

Total cross sections for charge transfer and electron detachment for collisions of a variety of negative ions with atomic hydrogen have been separately determined for laboratory collision energies ranging from about 5 eV to 500 eV. The experiments are performed with an apparatus that utilizes a crossed-beam configuration with a radio-frequency discharge as the source of atomic hydrogen.;For collisions of H{dollar}\sp-{dollar}(D{dollar}\sp-{dollar}) with H the charge transfer cross sections increase monotonically with decreasing energy and display an isotope effect. at the lowest collision energies, the electron detachment cross sections are about one order of magnitude smaller than those for charge transfer; for the two projectiles the detachment cross sections are identical when compared at the same relative collision energy.;Total electron detachment cross sections have also been measured for collisions of Halogen anions with atomic hydrogen. For F{dollar}\sp-{dollar}, Cl{dollar}\sp-{dollar}, and Br{dollar}\sp-{dollar} projectiles the measured detachment cross sections increase with decreasing collision energy, and no energetic threshold is indicated; no charge transfer is observed. For I{dollar}\sp-{dollar} + H, however, the detachment cross sections are small at low collision energies, and increase rapidly with increasing energy. HI{dollar}\sp-{dollar} is known to form a stable molecular anion, and a small charge transfer cross section is measured to be less than 1 A{dollar}\sp2{dollar} at the highest collision energy.;For collisions of O{dollar}\sp-{dollar} and S{dollar}\sp-{dollar} with atomic hydrogen, electron detachment is also found to be the dominant electron loss mechanism, and the measured total detachment cross sections are found to increase with decreasing collision energy. For both projectiles, charge transfer cross sections are measured to be small and energetic thresholds are indicated.;The experimental results are compared with several calculations and previous measurements that overlap the present results at the highest energies, and are discussed, where possible, in terms of various intermolecular potentials which have been calculated previously

Are Gift Cards Really Liabilities? A Class Exercise Exploring Starbucks Corporation

Stored value cards represent an important and increasingly large portion of many retailers’ revenue streams. While the outstanding balances on such cards represent accounting liabilities, these cards provide a myriad of benefits to the issuing firms (e.g., an upfront collection of cash, increased customer loyalty, and the potential for breakage or non-redemption of the card value). To illustrate the accounting treatment and revenue recognition concepts of gift cards, this exercise uses actual data from an annual report of Starbucks Corporation. The exercise introduces students to the nature of gift cards, how cards may impact customer spending, and other managerial implications. Finally, this exercise allows students to rethink their views about the nature of accounting liabilities and how they are often beneficial to a firm’s operations. Pretest and posttest measurements provide evidence of the exercise’s efficacy in achieving desired student learning outcomes

With Coronavirus Ravaging the Economy, Congress Shows Highest Tax Priorities: An Exploration of the Provisions in the CARES Act and Beyond

The virus known as SARS–CoV–21 (Coronavirus) swept over the United States in ways that no other crisis has affected modern society. While the Spanish Flu of 1918 has often been cited for its pandemic similarities to the Coronavirus, from an economic standpoint the attacks of September 11, 2001, and the Great Recession of 2008 are perhaps the Coronavirus’s best analogy for the modern economic carnage that has occurred. In those previous events, Congress responded with sweeping legislation like Dodd–Frank and the Patriot Act. With the Coronavirus, Congress responded with the CARES Act. Within the CARES Act are historical changes to the tax code. By exploring the provisions of the CARES Act, taxpayers receive a glimpse into Congress’s highest priorities in times of crisis. This article explores those changes in the tax law with the hope of providing taxpayers some insight into which priorities Congress views as most vital to a country in crisis

Small steps on the slippery road to life: Molecular synthesis in astrophysical ices initiated by low energy electron impact

Abstract: We report the synthesis and desorption of new chemical species from simple molecular surface ices irradiated by low energy (<60 eV) electrons. For CD4 ices we observe the formation and desorption of energetic ions such as D3+, CD5+, and C2Dn+ (n = 2–5), as well as three carbon containing chains, that are also observed to desorb from C2D2 films; for oxygen rich methane ices we observe the synthesis and desorption of H2O+, H3O+, as well as formaldehyde type cations, viz., HnCO+ (n = 1–3), among others. The formation of all these pre-biotic molecular species, produced here by low-energy electron-impact-initiated cation-reactions in simple molecular films, suggests that similar mechanisms may lead to the synthesis of life's most basic molecular components in planetary, or astrophysical surface ices that are continuously subjected to the types of space radiations (UV, X- or γ-ray, or heavy ions) that can generate such low energy secondary electrons

Screening Model of Magnetotransport Hysteresis Observed in Bilayer Quantum Hall Systems

We report on theoretical and experimental investigations of a novel hysteresis effect that has been observed on the magnetoresistance of quantum-Hall bilayer systems. Extending to these system a recent approach, based on the Thomas-Fermi-Poisson nonlinear screening theory and a local conductivity model, we are able to explain the hysteresis as being due to screening effects such as the formation of ``incompressible strips'', which hinder the electron density in a layer within the quantum Hall regime to reach its equilibrium distribution.Comment: 9 pages, 4 figures, to appear in Physica

Soft x-ray ionization induced fragmentation of glycine

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Laboratory intercomparison of Pleistocene bone radiocarbon dating protocols

Since its invention in the late 1940’s, radiocarbon dating has become an important tool for absolute dating. A prerequisite for the acceptance of this method is consistency between, and compatibility of, radiocarbon dates from different laboratories. To meet these requirements, international laboratory intercomparison studies with different sample materials are frequently performed (e.g. TIRI, FIRI, VIRI and, most recently, SIRI). Intercomparison is especially relevant and difficult for samples close to the dating limit of ~50 kBP, not least for bone samples. A radiocarbon intercomparison study between the Leibniz-Laboratory in Kiel (Germany), the Centre for Isotope Research (CIO) in Groningen (The Netherlands), and the Oxford Radiocarbon Accelerator Unit (ORAU; United Kingdom) was performed on three Pleistocene (MIS3) mammal bone samples from the Brick Quarry site Coenen (BQC) in Germany. The comparison of individually prepared and measured bone collagen radiocarbon activities, results from shared collagen measurements, and respective background signatures and correction points to the latter as the main factor responsible for observed differences in final given radiocarbon estimates

RADIOCARBON DATING CREMATED BONE:A CASE STUDY COMPARING LABORATORY METHODS

Radiocarbon (C-14) results on cremated bone are frequently published in high-ranking journals, but C-14 laboratories employ different pretreatment methods as they have divergent perceptions of what sources of contaminants might be present. We found pretreatment protocols to vary significantly between three laboratories (Brussels [RICH], Kid [KIA], and Groningen [CIO]), which all have a long history of dating cremated bone. We present a case study of 6 sets of replicate dates, to compare laboratory pretreatment protocols, and a further 16 sets of inter-laboratory replicate measurements, which compare specific steps of the conversion and measuring process. The C-14 results showed dates to be reproducible between the laboratories and consistent with the expected archaeological chronology. We found that differences in pretreatment, conversion to CO2 and accelerator mass spectrometry (AMS) measurement to have no measurable influence on the majority of obtained results, suggesting that any possible diagenesis was probably restricted to the most soluble</p