2,607 research outputs found

    Flat-plate drag measurements with vortex generators in turbulent boundary layer

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    Direct drag measurements were obtained on a flat plate with a spanwise row of vortex generators near the leading edge, to produce an array of stream wise vortices within the approaching turbulent boundary layer. The object was to explore the possibility of modifying the large scale structure of the boundary layer through embedded longitudinal vortices with a view to obtaining a reduction in wall shear. Both obstacle and vane type vortex generators were tested at free stream velocities 40 ft/sec to 130 ft/sec corresponding to plate length Reynolds no. 0.3 million to 0.8 million with a nominal boundary layer thickness of approximately 0.6 in. at the leading edge. A few vortex generator configurations were tested both on and off the plate to measure the total drag as well as the plate drag alone. The obstacle type devices reduced the plate drag, indicating that the wake momentum defect predominated even in the presence of streamwise vortices. The vane type vortex generators however always increased the plate drag

    Impact of Japanese Mergers on Shareholder Wealth: An Analysis of Bidder and Target Companies

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    The market for corporate control in the second largest economy in the world behaves very different from that in the U.S. Using a sample of 91 mergers in the period 1982-2003 we document several distinctive features of this market in Japan. First, we show that in stark contrast to the pro-cyclical U.S. merger waves, mergers in Japan tend to be counter-cyclical, both with respect to the general economy as well as with respect to stock market valuations. Second, and again in contrast to the U.S. experience, we find that a significant fraction of Japanese mergers are orchestrated by the main banks; in such cases, mergers are not between two weak companies, but at least one of the merging companies is financially strong. Other distinctive features of Japanese mergers are the positive pre-announcement returns accruing to both bidders and targets, with bidders capturing approximately half the gains that accrue to target firms. We also find differential shareholder wealth effects in the bubble period (1982-1989), the early 1990s, and the post-financial regulation regime (1997-2003). Overall our results point to a market for corporate control that is distinctly less shareholder-centered than that in the U.S. and one where creditors play an important, perhaps dominant, role.mergers;Japanse mergers;corporate control;take-over

    Maintaining regularity and generalization in data using the minimum description length principle and genetic algorithm: case of grammatical inference

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    In this paper, a genetic algorithm with minimum description length (GAWMDL) is proposed for grammatical inference. The primary challenge of identifying a language of infinite cardinality from a finite set of examples should know when to generalize and specialize the training data. The minimum description length principle that has been incorporated addresses this issue is discussed in this paper. Previously, the e-GRIDS learning model was proposed, which enjoyed the merits of the minimum description length principle, but it is limited to positive examples only. The proposed GAWMDL, which incorporates a traditional genetic algorithm and has a powerful global exploration capability that can exploit an optimum offspring. This is an effective approach to handle a problem which has a large search space such the grammatical inference problem. The computational capability, the genetic algorithm poses is not questionable, but it still suffers from premature convergence mainly arising due to lack of population diversity. The proposed GAWMDL incorporates a bit mask oriented data structure that performs the reproduction operations, creating the mask, then Boolean based procedure is applied to create an offspring in a generative manner. The Boolean based procedure is capable of introducing diversity into the population, hence alleviating premature convergence. The proposed GAWMDL is applied in the context free as well as regular languages of varying complexities. The computational experiments show that the GAWMDL finds an optimal or close-to-optimal grammar. Two fold performance analysis have been performed. First, the GAWMDL has been evaluated against the elite mating pool genetic algorithm which was proposed to introduce diversity and to address premature convergence. GAWMDL is also tested against the improved tabular representation algorithm. In addition, the authors evaluate the performance of the GAWMDL against a genetic algorithm not using the minimum description length principle. Statistical tests demonstrate the superiority of the proposed algorithm. Overall, the proposed GAWMDL algorithm greatly improves the performance in three main aspects: maintains regularity of the data, alleviates premature convergence and is capable in grammatical inference from both positive and negative corpora

    Reactions of Organotin Isopropoxides with Acetyl Pseudo halides

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    1099-110

    Exploring the intersections of LGBTQ experience and social work education: a scoping review

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    Lesbian, gay, bisexual, transgender, and queer (LGBTQ) issues, experiences, and theorizing have had limited representation within social work education. In recent years there has been an increase in the scholarly discourse regarding queer and trans issues and social work education, but little is known about the landscape of this body of published work. In this scoping review, we explored peerreviewed literature regarding the intersections of social work education and queer and trans experience, issues, and theorizing. Utilizing major academic databases, we identified 54 articles published in social work literature from 2010 to 2020 that met inclusion criteria. Topical areas of study included: classroom experiences of queer and trans students/faculty, student/faculty attitudes toward LGBTQ people, integration of gender and sexuality content within social work curriculum, and pedagogical strategies. In addition, we analyzed rationales for the research presented, theoretical frameworks employed, representation of identities, engagement with race, authors’ identity disclosure, and recommendations for social work education. We suggest that more scholarship is needed within social work education that centers the lived experiences of queer and trans people; asks a range of questions rooted in varied theories and epistemologies; and decenters whiteness and focuses on intersectionality within queer and trans communities

    Risks of chronic metabolic acidosis in patients with chronic kidney disease

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    Risks of chronic metabolic acidosis in patients with chronic kidney disease Metabolic acidosis is associated with chronic renal failure (CRF). Often, maintenance dialysis therapies are not able to reverse this condition. The major systemic consequences of chronic metabolic acidosis are increased protein catabolism, decreased protein synthesis, and a negative protein balance that improves after bicarbonate supplementation. Metabolic acidosis also induces insulin resistance and a decrease in the elevated serum leptin levels associated with CRF. These three factors may promote protein catabolism in maintenance dialysis patients. Available data suggest that metabolic acidosis is both catabolic and anti-anabolic. Several clinical studies have shown that correction of metabolic acidosis in maintenance dialysis patients is associated with modest improvements in nutritional status. Preliminary evidence indicates that metabolic acidosis may play a role in β2-microglobulin accumulation, as well as the hypertriglyceridemia seen in renal failure. Interventional studies for metabolic acidosis have yielded inconsistent results in CRF and maintenance hemodialysis patients. In chronic peritoneal dialysis patients, the mitigation of acidemia appears more consistently to improve nutritional status and reduce hospitalizations. Large-scale, prospective, randomized interventional studies are needed to ascertain the potential benefits of correcting acidemia in maintenance hemodialysis patients. To avoid adverse events, an aggressive management approach is necessary to correct metabolic acidosis. Clinicians should attempt to adhere to the National Kidney Foundation Kidney Disease Outcome Quality Initiative (K/DOQI) guidelines for maintenance dialysis patients. The guidelines recommend maintenance of serum bicarbonate levels at 22 mEq/L or greater

    SOME RESULTS ON THE BEST MATCH PROBLEM

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    The best-match problem is concerned with the complexity of finding the best match between a randomly chosen query word and the members of a randomly chosen set of data words. Of principal interest is whether it is possible to significantly reduce the search time required, as compared to exhaustive comparison, by use of memory redundancy (file structure). Minskv and Papert conjecture that the speed-up values of large memory redundancies is very small, and for large data sets with long word lengths there are no practical alternatives to large searches that inspect large parts of memory . For this report we present two algorithms that do yield significant speed-up, although at the cost of large memory redundancies. (Whether these algorithms constitute counterexamples to the Minskv-Papert conjecture depends on one\u27s interpretation of their term “large memory redundancies .) The algorithms are subjected to statistical analysis and time-memory trade-off curves are given
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