Three-dimensional instability in flow over a backward-facing step

Results are reported from a three-dimensional computational stability analysis of flow over a backward-facing step with an expansion ratio (outlet to inlet height) of 2 at Reynolds numbers between 450 and 1050. The analysis shows that the first absolute linear instability of the steady two-dimensional flow is a steady three-dimensional bifurcation at a critical Reynolds number of 748. The critical eigenmode is localized to the primary separation bubble and has a flat roll structure with a spanwise wavelength of 6.9 step heights. The system is further shown to be absolutely stable to two-dimensional perturbations up to a Reynolds number of 1500. Stability spectra and visualizations of the global modes of the system are presented for representative Reynolds numbers

Teacher Understanding and Perception of a Response to Intervention Program in a Rural, Western North Carolina School District

Response to Intervention, aka Response to Instruction (RtI), is a multi-tiered instructional process designed to provide research-based interventions to struggling learners. It has recently gained increased popularity with the perceived failure of the discrepancy formula model of placing children in special education services and with the recent reauthorization of the Individuals with Disabilities Education Act. Because RtI is just gaining ground in the field of education, limited research regarding teachers\u27 perceptions of the process is available. This research project utilized a mixed-methods approach, combining survey and interview data, to assess teacher understanding and perception of RtI in a rural North Carolina community. Both schools included in the study are currently piloting the RtI process. The results of the study found that even though most teachers seem to have a grasp on the roles and responsibilities associated with RtI, many teachers have substantial concerns regarding the implementation process. Most notably, teachers were concerned with the amount of time that was being dedicated to the RtI process and to the lack of available manpower. Teachers also noted improvements that could be made to improve the implementation process. Teachers specifically identified the importance of strong educational leadership within the school building as a factor in the success or failure of RtI within the schools. Detail

Hydrologic investigations of the Burge Branch Watershed : for 1960, 1961, 1962 water years

Digitized 2007 AES.Includes bibliographical references (pages 43-44)

Unknowable bodies, unthinkable sexualities: lesbian and transgender legal invisibility in the Toronto women's bathhouse raid

Although litigation involving sexual orientation and gender identity discrimination claims has generated considerable public attention in recent years, lesbian and transgender bodies and sexualities still remain largely invisible in Anglo-American courts. While such invisibility is generally attributed to social norms that fail to recognize lesbian and transgender experiences, the capacity to 'not see' or 'not know' queer bodies and sexualities also involves wilful acts of ignorance. Drawing from R. v Hornick (2002) a Canadian case involving the police raid of a women's bathhouse, this article explores how lesbian and transgender bodies and sexualities are actively rendered invisible via legal knowledge practices, norms and rationalities. It argues that limited knowledge and limited thinking not only regulate the borders of visibility and belonging, but play an active part in shaping identities, governing conduct and producing subjectivity

Striking the Right Balance of Intermolecular Coupling for High-Efficiency Singlet Fission

Singlet fission is a process that splits collective excitations, or excitons, into two with unity efficiency. This exciton splitting process, unique to molecular photophysics, has the potential to considerably improve the efficiency of optoelectronic devices through more efficient light harvesting. While the first step of singlet fission has been characterized in great detail, subsequent steps critical to achieving overall highly-efficient singlet-to-triplet conversion are only just beginning to become well understood. One of the most elementary suggestions, which has yet to be tested, is that an appropriately balanced coupling is necessary to ensure overall highly efficient singlet fission; that is, the coupling needs to be strong enough so that the first step is fast and efficient, yet weak enough to ensure the independent behavior of the resultant triplets. In this work, we show how high overall singlet-to-triplet conversion efficiencies can be achieved in singlet fission by ensuring that the triplets comprising the triplet pair behave as independently as possible. We show that side chain sterics govern local packing in amorphous pentacene derivative nanoparticles, and that this in turn controls both the rate at which triplet pairs form and the rate at which they decay. We show how compact side chains and stronger couplings promote a triplet pair that effectively couples to the ground state, whereas bulkier side chains promote a triplet pair that appears more like two independent and long-lived triplet excitations. Our results show that the triplet pair is not emissive, that its decay is best viewed as internal conversion rather than triplet–triplet annihilation, and perhaps most critically that, in contrast to a number of recent suggestions, the triplets comprising the initially formed triplet pair cannot be considered independently. This work represents a significant step toward better understanding intermediates in singlet fission, and how molecular packing and couplings govern overall triplet yields

Status of the TESS Science Processing Operations Center

The Transiting Exoplanet Survey Satellite (TESS) science pipeline is being developed by the Science Processing Operations Center (SPOC) at NASA Ames Research Center based on the highly successful Kepler Mission science pipeline. Like the Kepler pipeline, the TESS science pipeline will provide calibrated pixels, simple and systematic error-corrected aperture photometry, and centroid locations for all 200,000+ target stars, observed over the 2-year mission, along with associated uncertainties. The pixel and light curve products are modeled on the Kepler archive products and will be archived to the Mikulski Archive for Space Telescopes (MAST). In addition to the nominal science data, the 30-minute Full Frame Images (FFIs) simultaneously collected by TESS will also be calibrated by the SPOC and archived at MAST. The TESS pipeline will search through all light curves for evidence of transits that occur when a planet crosses the disk of its host star. The Data Validation pipeline will generate a suite of diagnostic metrics for each transit-like signature discovered, and extract planetary parameters by fitting a limb-darkened transit model to each potential planetary signature. The results of the transit search will be modeled on the Kepler transit search products (tabulated numerical results, time series products, and pdf reports) all of which will be archived to MAST

Cost of operating power equipment on Oregon farms

Published June 1942. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

A general co-expression network-based approach to gene expression analysis: comparison and applications

<p>Abstract</p> <p>Background</p> <p>Co-expression network-based approaches have become popular in analyzing microarray data, such as for detecting functional gene modules. However, co-expression networks are often constructed by ad hoc methods, and network-based analyses have not been shown to outperform the conventional cluster analyses, partially due to the lack of an unbiased evaluation metric.</p> <p>Results</p> <p>Here, we develop a general co-expression network-based approach for analyzing both genes and samples in microarray data. Our approach consists of a simple but robust rank-based network construction method, a parameter-free module discovery algorithm and a novel reference network-based metric for module evaluation. We report some interesting topological properties of rank-based co-expression networks that are very different from that of value-based networks in the literature. Using a large set of synthetic and real microarray data, we demonstrate the superior performance of our approach over several popular existing algorithms. Applications of our approach to yeast, Arabidopsis and human cancer microarray data reveal many interesting modules, including a fatal subtype of lymphoma and a gene module regulating yeast telomere integrity, which were missed by the existing methods.</p> <p>Conclusions</p> <p>We demonstrated that our novel approach is very effective in discovering the modular structures in microarray data, both for genes and for samples. As the method is essentially parameter-free, it may be applied to large data sets where the number of clusters is difficult to estimate. The method is also very general and can be applied to other types of data. A MATLAB implementation of our algorithm can be downloaded from <url>http://cs.utsa.edu/~jruan/Software.html</url>.</p

Comparing Notes: Recording and Criticism

This chapter charts the ways in which recording has changed the nature of music criticism. It both provides an overview of the history of recording and music criticism, from the advent of Edison’s Phonograph to the present day, and examines the issues arising from this new technology and the consequent transformation of critical thought and practice