Authentic Discovery Projects in Statistics

We report the activities and findings of a 3-year project, ―Authentic, Career-Specific, Discovery Learning Projects in Introductory Statistics,‖ funded by the National Science Foundation. The project scope includes: 1) development of teaching materials for using discovery learning projects to teach statistics; 2) training secondary teachers to use the materials developed; 3) evaluation of student outcomes, in both content knowledge and attitudes toward statistics; and 4) extending and refining teacher training. With input from an interdisciplinary team of instructors, materials were developed to assist the teacher in facilitating collaborative discovery projects using linear regression techniques and comparison techniques with appropriate t-tests. Web-based student and instructor guides authored to facilitate these projects are now available online. Five pilot instructors used the materials in their classes. Data collected from the instructors included qualitative data about teacher experiences and observations while employing the materials, as well as quantitative data about student performance and attitudes. These findings were used to inform a one-day teacher training workshop on effective use of statistics projects with the materials developed. Preliminary data analysis suggests that students in classes using the discovery projects achieve higher content knowledge and stronger perceived usefulness of statistics than do their traditional class counterparts

Determining the Future for Louisiana Sugar Cane Products, Inc.: A Case Study Analyzing Vertical Coordination Options

Deciding how to coordinate activities can be a challenge posed in any marketing chain. This case involves an agricultural cooperative that has focused entirely on marketing raw sugar cane for additional refinement. Recent dramatic shifts in the sector have caused the members of the cooperative to consider building a facility that will process the raw sugar cane. In so doing, the cooperative can consider using the spot market, using contracts, vertically coordinating, or vertically integrating. This case study of Louisiana Sugar Cane Products, Inc. is a unique, real-life case that can be widely used in marketing and cooperatives courses.Agribusiness, Crop Production/Industries,

Design and development of a deployable self-inflating adaptive membrane

Space structures nowadays are often designed to serve just one objective during their mission life, examples include truss structures that are used as support structures, solar sails for propulsion or antennas for communication. Each and every single one of these structures is optimized to serve just their distinct purpose and are more or less useless for the rest of the mission and therefore dead weight. By developing a smart structure that can change its shape and therefore adapt to different mission requirements in a single structure, the flexibility of the spacecraft can be increased by greatly decreasing the mass of the entire system. This paper will introduce such an adaptive structure called the Self-inflating Adaptive Membrane (SAM) concept which is being developed at the Advanced Space Concepts Laboratory of the University of Strathclyde. An idea presented in this paper is to adapt these basic changeable elements from nature’s heliotropism. Heliotropism describes a movement of a plant towards the sun during a day; the movement is initiated by turgor pressure change between adjacent cells. The shape change of the global structure can be significant by adding up these local changes induced by local elements, for example the cell’s length. To imitate the turgor pressure change between the motor cells in plants to space structures, piezoelectric micro pumps are added between two neighboring cells. A passive inflation technique is used for deploying the membrane at its destination in space. The trapped air in the spheres will inflate the spheres when subjected to vacuum, therefore no pump or secondary active deployment methods are needed. The paper will present the idea behind the adaption of nature’s heliotropism principle to space structures. The feasibility of the residual air inflation method is verified by LS-DYNA simulations and prototype bench tests under vacuum conditions. Additionally, manufacturing techniques and folding patterns are presented to optimize the actual bench test structure and to minimize the required storage volume. It is shown that through a bio-inspired concept, a high ratio of adaptability of the membrane can be obtained. The paper concludes with the design of a technology demonstrator for a sounding rocket experiment to be launched in March 2013 from the Swedish launch side Esrange

High Spin-low Spin Crossover and Antiferromagnetic Interactions in Tris(1-pyrrolidinecarbodithioato)iron(III) and the 4-morpholine (FeM) and Dibutyl Analogs, Effect of Recrystallization Solvent, and Crystal Structure of FeM·nitrobenzene

High sensitivity magnetic susceptibility determinations, especially in the range 1.2-4.2 K on pure and dilute tris(pyrrolidinecarbodithioato)iron(III) (FeP) in its high spin form, show that a maximum at about 2 K is caused by antiferromagnetic interactions. The analogous chromium(III) complex does not exhibit significant antiferromagnetism compared to that of the iron complex, and it is likely that the upper e electrons possessed by the iron and not by the chromium are responsible for the bulk of the antiferromagnetism. As the iron atoms are about 9 Å apart in discrete molecules, the antiferromagnetic interactions presumably occur between unpaired spins delocalized on to the ligands of adjacent molecules. This is in keeping with NMR evidence that spin delocalization is greater in the iron(III) than in the chromium(III) complex. When diluted with large amounts of the cobalt(III) analog (CoP), FeP exhibits a spin state equilibrium. Thus, the structure of the FeP molecule is modified slightly (presumably with shortening of the Fe-S bond) to approach that of the CoP host lattice, which has a shorter metal-sulfur bond. The previous history of the samples of ferric dithiocarbamate complexes is shown to be far more important than had previously been suspected: When crystallized from benzene, FeP exhibits a high spin-low spin equilibrium, in constrast with the pure high spin behavior of the complex when not crystallized from benzene. The effect of adding 7% of benzene to the lattice is much greater than that of adding 50% of CoP. The dibutyl analog shows similar effects. The tris(4- morpholinecarbodithioato-S,S\u27)iron(III) complex FeM is shown, by single crystal x-ray data, to contain short Fe-S bond lengths (average 2.353 Å) when recrystallized from nitrobenzene. This indicates that the complex is principally low spin, in keeping with the observed magnetism and with the general strong solvent effect on the spin state. It is now proposed that the difference in Fe-S bond lengths between FeP crystallized from chloroform and FeP from benzene (the reverse of the expected differences) is due to experimental error. Crystal data for FeM-nitrobenzene: space group P21/c, Z = 4, a = 9.713(3) Å, b = 31.419(8) Å, c = 9.718(2) Å, β = 105.04(2)°, V = 2864 Å3, R = 3.3%, 2712 reflections

Enhanced structural correlations accelerate diffusion in charge-stabilized colloidal suspensions

Theoretical calculations for colloidal charge-stabilized and hard sphere suspensions show that hydrodynamic interactions yield a qualitatively different particle concentration dependence of the short-time self-diffusion coefficient. The effect, however, is numerically small and hardly accessible by conventional light scattering experiments. Applying multiple-scattering decorrelation equipment and a careful data analysis we show that the theoretical prediction for charged particles is in agreement with our experimental results from aqueous polystyrene latex suspensions.Comment: 1 ps-file (MS-Word), 14 page

The Biological Standard of Living in the two Germanies.

Physical stature is used as a proxy for the biological standard of living in the two Germanies before and after unification in an analysis of a cross-sectional sample (1998) of adult heights, as well as among military recruits of the 1990s. West Germans tended to be taller than East Germans throughout the period under consideration. Contrary to official proclamations of a classless society, there were substantial social differences in physical stature in East-Germany. Social differences in height were greater in the East among females, and less among males than in the West. The difficulties experienced by the East-German population after 1961 is evident in the increase in social inequality of physical stature thereafter, as well as in the increasing gap relative to the height of the West-German population. After unification, however, there is a tendency for East-German males, but not of females, to catch up with their West-German counterparts

Crystallization in suspensions of hard spheres: A Monte Carlo and Molecular Dynamics simulation study

The crystallization of a metastable melt is one of the most important non equilibrium phenomena in condensed matter physics, and hard sphere colloidal model systems have been used for several decades to investigate this process by experimental observation and computer simulation. Nevertheless, there is still an unexplained discrepancy between simulation data and experimental nucleation rate densities. In this paper we examine the nucleation process in hard spheres using molecular dynamics and Monte Carlo simulation. We show that the crystallization process is mediated by precursors of low orientational bond-order and that our simulation data fairly match the experimental data sets

Homogeneous nucleation of colloidal melts under the influence of shearing fields

We study the effect of shear flow on homogeneous crystal nucleation, using Brownian Dynamics simulations in combination with an umbrella sampling like technique. The symmetry breaking due to shear results in anisotropic radial distribution functions. The homogeneous shear rate suppresses crystal nucleation and leads to an increase of the size of the critical nucleus. These observations can be described by a simple, phenomenological extension of classical nucleation theory. In addition, we find that nuclei have a preferential orientation with respect to the direction of shear. On average the longest dimension of a nucleus is along the vorticity direction, while the shortest dimension is preferably perpendicular to that and slightly tilted with respect to the gradient direction.Comment: 10 pages, 8 figures, Submitted to J. Phys.: Condens. Matte