1,217 research outputs found
On five-dimensional non-extremal charged black holes and FRW cosmology
We consider static non-extremal charged black hole solutions in the context
of N=2 gauged supergravity theories in five dimensions, and we show that they
satisfy first-order flow equations. Then we analyze the motion of the dual
brane in these black hole backgrounds. We express the entropy in terms of a
Cardy-Verlinde-type formula, and we show that the equations describing the FRW
cosmology on the brane have a form that is similar to the equations for the
entropy and for the Casimir energy on the brane. We also briefly comment on the
inclusion of a Gauss-Bonnet term in the analysis.Comment: 27 pages,5 figures, references adde
On Subextensive Corrections to Fluid Dynamics from Gravity
We use the fluid-gravity correspondence to compute subextensive corrections,
proportional to the shear tensor, to the energy-momentum tensor of fluids on
three-spheres. The dual configurations we consider are charged black hole
solutions of N = 2 gauged supergravity theories in five dimensions.Comment: 26 pages, LaTeX, added comment
What Does an Exemplary Middle School Mathematics Teacher Look Like? The Use of a Professional Development Rubric
A School University Research Network (SURN) committee composed of current mathematics teachers, central office math supervisors, building administrators, mathematicians, and mathematics educators researched numerous sources regarding best practices in mathematics instruction. The resulting professional development rubric synthesizes their findings and can serve a professional development role by providing teachers and administrators with a tool to develop clarity and consensus on best mathematics instructional practices, and how these practices are implemented in the classroom. It is also being used as a tool for cooperating teachers in their supervision of student teachers and as a reflective method for self-evaluation
Threading, Stitching, and Storytelling: Using CBPR and Blackfoot Knowledge and Cultural Practices to Improve Domestic Violence Services for Indigenous Women
This article discusses a community-based participatory research (CBPR) project at two women’s emergency shelters in rural southwestern Alberta. The CBPR project aimed to improve shelter services on and off reserve in our area by engaging the voices of Indigenous women who had experienced domestic violence. The project’s methods were participatory appraisal and arts-based work re-imagined through Blackfoot cultural practices of storytelling and shawl making. The project created a rare safe space where thirteen Blackfoot women emphasised DV services should provide opportunities to connect with family and community and role model Blackfoot knowledge. Role modelling traditional knowledges aids developing life and parenting skills, opening up pathways for Indigenous women to more positive, secure futures. These women’s recommendations impelled this article to challenge the individualized case management model and discourses of cultural competence dominating Canadian DV services, which isolate and marginalize Indigenous women when they seek help. We highlight resources existing in Blackfoot communities to manage and prevent violence by protecting and facilitating Indigenous women’s connections to their communities and cultures, and offer ways to utilize these more effectively in service settings
Measuring individual overpotentials in an operating solid-oxide electrochemical cell
We use photo-electrons as a non-contact probe to measure local electrical
potentials in a solid-oxide electrochemical cell. We characterize the cell in
operando at near-ambient pressure using spatially-resolved X-ray photoemission
spectroscopy. The overpotentials at the interfaces between the Ni and Pt
electrodes and the yttria-stabilized zirconia (YSZ) electrolyte are directly
measured. The method is validated using electrochemical impedance spectroscopy.
Using the overpotentials, which characterize the cell's inefficiencies, we
compare without ambiguity the electro-catalytic efficiencies of Ni and Pt,
finding that on Ni H_2O splitting proceeds more rapidly than H2 oxidation,
while on Pt, H2 oxidation proceeds more rapidly than H2O splitting.Comment: corrected; Phys. Chem. Chem. Phys., 201
Comparison of multispectral remote-sensing techniques for monitoring subsurface drain conditions
The following multispectral remote-sensing techniques were compared to determine the most suitable method for routinely monitoring agricultural subsurface drain conditions: airborne scanning, covering the visible through thermal-infrared (IR) portions of the spectrum; color-IR photography; and natural-color photography. Color-IR photography was determined to be the best approach, from the standpoint of both cost and information content. Aerial monitoring of drain conditions for early warning of tile malfunction appears practical. With careful selection of season and rain-induced soil-moisture conditions, extensive regional surveys are possible. Certain locations, such as the Imperial Valley, Calif., are precluded from regional monitoring because of year-round crop rotations and soil stratification conditions. Here, farms with similar crops could time local coverage for bare-field and saturated-soil conditions
Design, implementation, evaluation and application of a 32-channel radio frequency signal generator for thermal magnetic resonance based anti-cancer treatment
Thermal Magnetic Resonance (ThermalMR) leverages radio frequency (RF)-induced heating to examine the role of temperature in biological systems and disease. To advance RF heating with multi-channel RF antenna arrays and overcome the shortcomings of current RF signal sources, this work reports on a 32-channel modular signal generator (SG(PLL)). The SG(PLL) was designed around phase-locked loop (PLL) chips and a field-programmable gate array chip. To examine the system properties, switching/settling times, accuracy of RF power level and phase shifting were characterized. Electric field manipulation was successfully demonstrated in deionized water. RF heating was conducted in a phantom setup using self-grounded bow-tie RF antennae driven by the SG(PLL). Commercial signal generators limited to a lower number of RF channels were used for comparison. RF heating was evaluated with numerical temperature simulations and experimentally validated with MR thermometry. Numerical temperature simulations and heating experiments controlled by the SG(PLL) revealed the same RF interference patterns. Upon RF heating similar temperature changes across the phantom were observed for the SG(PLL) and for the commercial devices. To conclude, this work presents the first 32-channel modular signal source for RF heating. The large number of coherent RF channels, wide frequency range and accurate phase shift provided by the SG(PLL) form a technological basis for ThermalMR controlled hyperthermia anti-cancer treatment
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