Using the Big Ideas in Cosmology to Teach College Students

Recent advances in our understanding of the Universe have revolutionized our view of its structure, composition and evolution. However, these new ideas have not necessarily been used to improve the teaching of introductory astronomy students. In this project, we have conducted research into student understanding of cosmological ideas so as to develop effective web-based tools to teach basic concepts important to modern cosmology. The tools are intended for use at the introductory college level. Our research uses several instruments, including open-ended and multiple choice surveys conducted at multiple institutions, as well as interviews and course artifacts at one institution, to ascertain what students know regarding modern cosmological ideas, what common misunderstandings and misconceptions they entertain, and what sorts of materials can most effectively overcome student difficulties in learning this material. These data are being used to create a suite of interactive, web-based tutorials that address the major ideas in cosmology using real data. Having students engage with real data is a powerful means to help students overcome certain misconceptions. Students master the scientific concepts and reasoning processes that lead to our current understanding of the universe through interactive tasks, prediction and reflection, experimentation, and model building.Comment: 2012 Fermi Symposium proceedings - eConf C12102

A New Site Index Model for Intensively Managed Loblolly Pine (Pinus taeda) Plantations in the West Gulf Coastal Plain

Site index (SI) estimation for loblolly pine (Pinus taeda L.) plantations is important for the successful management of this important commercial tree species in the West Gulf Coastal Plain of the United States. This study evaluated various SI models for intensively managed loblolly plantations in the West Gulf Coastal Plain using data collected from permanent plots installed in intensively managed loblolly pine plantations across east Texas and western Louisiana. Six commonly used SI models (Cieszewski GADA model, both Chapman-Richards ADA and GADA models, both Schumacher ADA and GADA models, and McDill-Amateis GADA model) were fit to the data and compared. The Chapman-Richards GADA model and the McDill-Amateis GADA model were similar and best in their fit statistics. These two models were further compared to the existing models (Diéguez-Aranda et al. 2006 (DA2006), Coble and Lee 2010 (CL2010)) commonly used in the region. Both the Chapman-Richards GADA and the McDill-Amateis GADA models consistently predicted greater heights up to age 25 than the models of DA2006 and CL2010, with larger height differences for the higher quality sites, but predicted shorter heights thereafter. Ultimately, the McDill-Amateis GADA model was chosen as the best model for its consistency in predicting reasonable heights extrapolated beyond the range of the data. Foresters can use this model to make more informed silvicultural prescriptions for intensively managed loblolly pine plantations in the West Gulf Coastal Plain

What We Know about School-Based Health Centers: Literature on Outcomes, Cost Impact, Implementation, and Sustainability

Many children lack access to adequate healthcare in the United States. School Based Health Centers (SBHC) are a useful resource for accessing those needed services. The purpose of this study is to evaluate the available research for the strengths of SBHCs with improving health outcomes and health equity, cost impact of SBHCs, and best practices for implementing and sustaining an SBHC. The focus of this study was on reviewing the current literature on the impact of SBHCs on improving health equity, health outcomes, cost impact, and to establish best practices for implementing and sustaining an SBHC. Although the current literature is limited, there is a strong consensus that SBHCs improve health outcomes and health equity, are cost-effective, and there are strategies that can make implementing and sustaining an SBHC a success

Expansion, Geometry, and Gravity

In general-relativistic cosmological models, the expansion history, matter content, and geometry are closely intertwined. In this brief paper, we clarify the distinction between the effects of geometry and expansion history on the luminosity distance. We show that the cubic correction to the Hubble law, measured recently with high-redshift supernovae, is the first cosmological measurement, apart from the cosmic microwave background, that probes directly the effects of spatial curvature. We illustrate the distinction between geometry and expansion with a toy model for which the supernova results already indicate a curvature radius larger than the Hubble distance.Comment: 4 pages, 1 color figur

A qualitative analysis of the phases of involuntary childlessness

The purpose of this research was to explore and identify the psychosocial phases of involuntary childlessness in an effort to develop a hierarchical model. A stage development theoretical framework guided this research. Because of the lack of literature concerning the psychosocial aspects of involuntarily childless couples, it was necessary to utilize a qualitative research methodology which incorporated the analytic induction method. Subjects for this research were couples who consented to participate in a project explained as an exploratory study on involuntary childlessness. These 20 couples were between the ages of 25 and 40 years and of middle socioeconomic status. An involuntarily childless couple was operationally defined as a couple who had been attempting pregnancy for 12 months or more without either conception or carrying a fetus to full term. Subjects for this study were considered only if neither partner had been a biological parent

The sintering behavior of close-packed spheres

The sintering behavior and microstructural evolution of a powder compact is influenced strongly by initial properties, such as the relative density, the particle and pore size distribution, and the powder packing. While the influence of the former parameters on the microstructural evolution has been investigated in some detail, the impact of the initial packing of the powder has been mostly overlooked. However, research has shown that the sintering behavior of a powder can be significantly improved if the powder is regularly packed. This has been shown for monodisperse spherical TiO2 particles [1], which sintered 10 times faster and exhibited almost no grain growth compared to ordinary TiO2. Similar observations has been made for homogeneously packed Al2O3 [2], SiO2 [3], as well as a number of other materials [4]. Monodispersed spherical TiO2 particles have been shown to order in face-centered cubic (fcc) arrays, while the SiO2 powder forms stacked planes of hexagonal close-packed (hcp) particles. Close packing of monodispersed silica has also been observed [5]. Sintering of two-dimensional close packing cylinders has also been demonstrated experimentally [6–8] and numerically modeled [9,10], and the sintering of particle clusters in three dimensions has also been studied [11]

Controls on the composition and lability of dissolved organic matter in Siberia's Kolyma River basin

High-latitude northern rivers export globally significant quantities of dissolved organic carbon (DOC) to the Arctic Ocean. Climate change, and its associated impacts on hydrology and potential mobilization of ancient organic matter from permafrost, is likely to modify the flux, composition, and thus biogeochemical cycling and fate of exported DOC in the Arctic. This study examined DOC concentration and the composition of dissolved organic matter (DOM) across the hydrograph in Siberia's Kolyma River, with a particular focus on the spring freshet period when the majority of the annual DOC load is exported. The composition of DOM within the Kolyma basin was characterized using absorbance-derived measurements (absorbance coefficienta330, specific UV absorbance (SUVA254), and spectral slope ratio SR) and fluorescence spectroscopy (fluorescence index and excitation-emission matrices (EEMs)), including parallel factor analyses of EEMs. Increased surface runoff during the spring freshet led to DOM optical properties indicative of terrestrial soil inputs with high humic-like fluorescence, SUVA254, and low SRand fluorescence index (FI). Under-ice waters, in contrast, displayed opposing trends in optical properties representing less aromatic, lower molecular weight DOM. We demonstrate that substantial losses of DOC can occur via biological (∼30% over 28 days) and photochemical pathways (>29% over 14 days), particularly in samples collected during the spring freshet. The emerging view is therefore that of a more dynamic and labile carbon pool than previously thought, where DOM composition plays a fundamental role in controlling the fate and removal of DOC at a pan-Arctic scale