What we can learn from magnetic Compton scattering : application to the determination of spin polarization

Studies of spin-resolved electron momentum densities involve the measurement of the so-called magnetic Compton profile. This is a one-dimensional projection of the electron momentum distribution of only those electrons that contribute to the spin moment of a sample. The technique is applicable to ferri- and ferromagnetic materials. The profile is obtained via the inelastic 'Compton' scattering of high energy X-rays. Since electrons originating from different atomic orbitals have specific momentum densities, it is often possible to determine the origin of the magnetism present. Typically, interpretation requires the use of electronic structure calculations using molecular orbital and band structure approaches. Here, we highlight the application of the technique to the determination of the Fermi level spin polarization, the knowledge of which is important to the development of novel spintronic materials

A Critical Exploratory Analysis of Black Girls\u27 Achievement in 8th grade U.S. History

The purpose of this study was to utilize an ethnically homogeneous design to examine Black female student U.S. History content-specific knowledge. The study aims to elucidate the importance of single-group analyses as an alternative to between-group comparative designs. The present study utilized a critical, quantitative, descriptive research design to examine the achievement of Black girls in U.S. History from a strength-based and growth-focused perspective. The study contributes to the literature on Black girls’ achievement by applying a quantitative approach to intersectional research. This study utilized two subsamples of Black 8th grade girls from the 2006 and 2010 National Assessment of Educational Progress (N = 4,490). Mean differences in Black girls’ specialized U.S. History content knowledge were assessed using both descriptive statistics and an analysis of variance (ANOVA). The results indicate statistically significant growth overall, and on the democracy and world role domains. Data also indicate that scores on the democracy and culture domains were statistically significantly higher than scores on the technology and world role domains. This study provides implications for middle grades U.S. History achievement and the specific needs of Black girls

Temperature influence on the carbon isotopic composition of Orbulina universa and Globigerina bulloides (planktonic foraminifera)

Laboratory experiments with the planktonic foraminifera Orbulina universa (symbiotic) and Globigerina bulloides (nonsymbiotic) were used to examine the effects of temperature, irradiance (symbiont photosynthesis), [CO32-], [HPO42-], and ontogeny on shell d13C values. In ambient seawater ([CO32-] = 171 mmol kg-1), the d13C of O. universa shells grown under low light (LL) levels is insensitive to temperature and records the d13C value of seawater TCO2. In contrast, the d13C of high light (HL) shells increases ~0.4‰ across 15-25°C (+0.050‰/°C). This suggests that the d13C enrichment due to symbiont photosynthetic activity is temperature-dependent. A comparison of HL O. universa grown in elevated [CO32-] seawater with ambient specimens shows that temperature does not affect the slope of the d13C/[CO32-] relationship previously described [Spero et al., 1997]. The d13C of G. bulloides shells decreases across the 15-24°C temperature range and d13C:temperature slopes decrease with increasing shell size (-0.13, -0.10, and -0.09‰/°C in 11- 12-, and 13-chambered shells, respectively). The pattern of lower d13C values at higher temperatures likely results from the incorporation of more respired CO2 into the shell at higher metabolic rates. The d13C of HL O. universa increases with increased seawater [HPO42-]

A Proposal Concerning the Analysis of Shadows in Images by an Active Observer (Dissertation Proposal)

Shadows occur frequently in indoor scenes and outdoors on sunny days. Despite the information inherent in shadows about a scene\u27s geometry and lighting conditions, relatively little work in image understanding has addressed the important problem of recognizing shadows. This is an even more serious failing when one considers the problems shadows pose for many visual techniques such as object recognition and shape from shading. Shadows are difficult to identify because they cannot be infallibly recognized until a scene\u27s geometry and lighting are known. However, there are a number of cues which together strongly suggest the identification of a shadow. We present a list of these cues and methods which can be used by an active observer to detect shadows. By an active observer, we mean an observer that is not only mobile, but can extend a probe into its environment. The proposed approach should allow the extraction of shadows in real time. Furthermore, the identification of a shadow should improve with observing time. In order to be able to identify shadows without or prior to obtaining information about the arrangement of objects or information about the spectral properties of materials in the scene, we provide the observer with a probe with which to cast its own shadows. Any visible shadows cast by the probe can be easily identified because they will be new to the scene. These actively obtained shadows allow the observer to experimentally determine the number and location of light sources in the scene, to locate the cast shadows, and to gain information about the likely spectral changes due to shadows. We present a novel method for locating a light source and the surface on which a shadow is cast. It takes into account errors in imaging and image processing and, furthermore, it takes special advantage of the benefits of an active observer. The information gained from the probe is of particular importance in effectively using the various shadow cues. In the course of identifying shadows, we also present a new modification on an image segmentation algorithm. Our modification provides a general description of color images in terms of regions that is particularly amenable to the analysis of shadows

Darkness as a Positive Reinforcer in Weakly Electric Fish

Darkness was used as a positive reinforcer in 14 Gnathonemus petersii fish in an object discrimination task. One subject showed a significant learning response. This study provides preliminary support for the use of darkness as positive reinforcement in weakly electric fish and presents potential areas of interest for future study

Small Hydropower Potential in Missouri

Track I: Power GenerationIncludes audio file (20 min.)The overall objective of this research is to advance our understanding of how, and to what degree, small hydropower development can aid in the fight against global warming. The leading cause of climate change today is the burning of fossil fuels related to energy production. One approach to reducing greenhouse gas emissions, therefore, is to more actively switch to proven renewable technologies, including small hydropower, in the production of electricity and reduce the use of fossil fuels in electricity production. We make the important distinction in this research project between “small” and “traditional” hydropower plants, because “small” hydropower, at generation capacities of less than 30 MW per site, has few to no negative effects on local river ecosystems. This makes their benefits to reducing greenhouse gas emissions even more appealing. Additionally, small hydropower is a proven technology with a number of benefits besides just emissions-free electric power, including domestic reliability, decentralization externalities, and significant energy efficiency properties. Finally, development of small hydropower sites throughout Missouri would create jobs, help to satisfy growing energy demands, and qualify under Missouri's new Renewable Portfolio Standard, passed by the voters in November, 2008. This research documents the small hydropower sites available for development within the state of Missouri, the amount of carbon emissions that could be reduced by building these sites, and finally, it provides site-specific benefit-cost analyses of actual construction of these small hydropower plants. Preliminary results of this research find that while the costs of small hydropower development are not always small, the relative benefits are often much larger than expected. Small hydropower development would also create jobs, spur the economy, and strengthen valuable energy infrastructure in the U.S