4,152 research outputs found

    Nonsplit conics in the reduction of an arithmetic curve

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    For an algebraic function field F/KF/K and a discrete valuation vv of KK with perfect residue field kk, we bound the number of discrete valuations on FF extending vv whose residue fields are algebraic function fields of genus zero over kk but not ruled. Assuming that KK is relatively algebraically closed in FF, we find that the number of nonruled residually transcendental extensions of vv to FF is bounded by g+1\mathfrak{g}+1 where g\mathfrak{g} is the genus of F/KF/K. An application to sums of squares in function fields of curves over R( ⁣(t) ⁣)\mathbb{R}(\!(t)\!) is presented

    Faunistic and taxonomic updates on the Tenebrionidae of Malta (Coleoptera)

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    In the present work, original data is provided for two species of Alleculinae (Tenebrionidae) which were previously omitted from recent works related to this family. The old record of Isomira nitidula is found to be incorrect and should refer to I. melanophthalma. The record of Odocnemis exaratus must be attributed to a different species. Original data is also provided for a new record, Lyphia tetraphylla and for some other previously recorded species. Clamoris crenatus, Stenosis elongata and S. sardoa are excluded from the tenebrionid fauna of Malta whereas the record of Sepidium tricuspidatum tomentosum and Gunarus parvulus requires validation. An alien species, Zophobas opacus, is also recorded but its establishment in Malta cannot be confirmed. A check-list of the 61 species of Tenebrionidae known from Malta is also providedpeer-reviewe

    Splitting fields of conics and sums of squares of rational functions

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    Given a geometrically unirational variety over an infinite base field, we show that every finite separable extension of the base field that splits the variety is the residue field of a closed point. As an application, we obtain a characterization of function fields of smooth conics in which every sum of squares is a sum of two square

    Comparison of Hyperspectral Imagery Target Detection Algorithm Chains

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    Detection of a known target in an image has several different approaches. The complexity and number of steps involved in the target detection process makes a comparison of the different possible algorithm chains desirable. Of the different steps involved, some have a more significant impact than others on the final result the ability to find a target in an image. These more important steps often include atmospheric compensation, noise and dimensionality reduction, background characterization, and detection (matched filtering for this research). A brief overview of the algorithms to be compared for each step will be presented. This research seeks to identify the most effective set of algorithms for detecting a known tar get. Several different algorithms for each step will be presented, to include ELM, FLAASH, ACORN, MNF, PPI, N-FINDR, MAXD, and two matched filters that employ a structured background model OSP and ASD. The chains generated by these algorithms will be com pared using the Forest Radiance I HYDICE data set. Finally, ROC curves and AFAR values are calculated for each algorithm chain and a comparison of them is presented. Detection rates at a CFAR are also compared. Since a relatively small number of algorithms were used for each step, there were no definitive results generated. However, a comprehensive comparison of the chains using the above mentioned algorithms is presented

    Pioglitazone, NEET Family Proteins, and Galactose Modulation of Liver Cell Bioenergetics

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    MitoNEET was discovered through interactions with a labeled and photoactive derivative of pioglitazone (pio), a drug used to increase peripheral insulin sensitivity. Its unique coordination of a [2Fe-2S] cluster by three cysteine residues (Cys-72, Cys-74, and Cys-83) and one histidine (His-87) gives this cluster both stability and the ability to be donated to acceptor proteins. These qualities allow mitoNEET to participate in a diversity of biological functions. Functions of mitoNEET and the consequences of pioglitazone (pio) treatment in human hepatocellular carcinoma (HepG2) cells cultured in glucose or galactose-based medium were examined by respiration and proliferation studies. Pio treatment decreased complex I stimulated respiration for cells grown in both glucose and galactose-based medium. Additionally, pio was found to significantly decrease cell proliferation. HepG2 cells cultured in galactose exhibited significantly higher oxygen flux than those cultured in glucose-based medium, but proliferation of these cells was notably reduced. Interestingly, mitoNEET levels were substantially lower in cells cultured in galactose. We hypothesize that some of the effects of pio may depend on the cellular levels of mitoNEET and the metabolic consequences of culturing cancerous cells in a galactose-based medium

    Volunteer Growth in America: A Review of Trends Since 1974

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    The Corporation has produced a national report that for the first time tracks volunteering over a 30-year period. "Volunteer Growth in America: A Review of Trends Since 1974" illustrates how volunteering has rebounded to a 30-year high today -- rising by more than 32 percent over the past 16 years -- after declining between 1974 and 1989. The report found that older teenagers (ages 16-19) have more than doubled their time spent volunteering since 1989; that far from being a "Me Generation," that Baby Boomers are volunteering at sharply higher rates than did the previous generation at mid-life; and that the volunteer rate for Americans ages 65 years and over has increased 64 percent since 1974; and the proportion of Americans volunteering with an educational or youth service organization has seen a 63 percent increase just since just 1989. "Volunteer Growth in America" is based on statistics from the U.S. Census Bureau and the Bureau of Labor Statistics. The findings are encouraging while demonstrating that more engagement is needed to achieve a national goal of raising the number of volunteers from 65 million in 2005 to 75 million by 2010
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