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

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

Trapping electrons in electrostatic traps over the surface of helium

We have observed trapping of electrons in an electrostatic trap formed over the surface of liquid helium-4. These electrons are detected by a Single Electron Transistor located at the centre of the trap. We can trap any desired number of electrons between 1 and $\sim 30$. By repeatedly ($\sim 10^3-10^4$ times) putting a single electron into the trap and lowering the electrostatic barrier of the trap, we can measure the effective temperature of the electron and the time of its thermalisation after heating up by incoherent radiation.Comment: Presented at QFS06 - Kyoto, to be published in J. Low Temp. Phys., 6 pages, 3 figure

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-]

Fluctuations of a Greenlandic tidewater glacier driven by changes in atmospheric forcing : observations and modelling of Kangiata Nunaata Sermia, 1859–present

Acknowledgements. The authors wish to thank Stephen Price, Mauri Pelto, and the anonymous reviewer for their reviews and comments that helped to improve the manuscript. RACMO2.1 data were provided by Jan van Angelen and Michiel van den Broeke, IMAU, Utrecht University. MAR v3.2 data used for runoff calculations were provided by Xavier Fettweis, Department of Geography, University of Liège. The photogrammetric DEM used in Figs. 1 and 3 was provided by Kurt H. Kjær, Centre for GeoGenetics, University of Copenhagen. This research was financially supported by J. M. Lea’s PhD funding, NERC grant number NE/I528742/1. Support for F. M. Nick was provided through the Conoco-Phillips/Lundin Northern Area Program CRIOS project (Calving Rates and Impact on Sea Level).Peer reviewedPublisher PD

Supervision and Scholarly Writing: Writing to Learn - Learning to Write

This paper describes an action research project on postgraduate students’ scholarly writing in which I employed reflective approaches to examine and enhance my postgraduate supervisory practice. My reflections on three distinct cycles of supervision illustrate a shift in thinking about scholarly writing and an evolving understanding of how to support postgraduate students’ writing. These understandings provide the foundation for a future-oriented fourth cycle of supervisory practice, which is characterised by three principles, namely the empowerment of students as writers, the technological context of contemporary writing, and ethical issues in writing

Magneto-shear modes and a.c. dissipation in a two-dimensional Wigner crystal

The a.c. response of an unpinned and finite 2D Wigner crystal to electric fields at an angular frequency $\omega$ has been calculated in the dissipative limit, $\omega \tau \ll 1$, where $\tau ^{-1}$ is the scattering rate. For electrons screened by parallel electrodes, in zero magnetic field the long-wavelength excitations are a diffusive longitudinal transmission line mode and a diffusive shear mode. A magnetic field couples these modes together to form two new magneto-shear modes. The dimensionless coupling parameter $\beta =2(c_{t}/c_{l})|\sigma_{xy}/\sigma_{xx}|$ where $c_{t}$ and $c_{l}$ are the speeds of transverse and longitudinal sound in the collisionless limit and $\sigma_{xy}$ and $\sigma_{xx}$ are the tensor components of the magnetoconductivity. For $\beta \geqslant 1$, both the coupled modes contribute to the response of 2D electrons in a Corbino disk measurement of magnetoconductivity. For $\beta \gg 1$, the electron crystal rotates rigidly in a magnetic field. In general, both the amplitude and phase of the measured a.c. currents are changed by the shear modulus. In principle, both the magnetoconductivity and the shear modulus can be measured simultaneously.Comment: REVTeX, 7 pp., 4 eps figure