234 research outputs found

    The electrical resistance of vanadium-gold alloys

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    On scrimshaw precursors: a 13th-century carved and engraved sperm whale tooth

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    In der einschlägigen Forschung zur Walfängervolkskunst des "Scrimshaw" - den seit den 1820er Jahren populär gewordenen Seemannsarbeiten speziell auf und aus Pottwal- und Walroßzahn, Barten und Walknochen - werden künstlerisch bearbeitete Gegenstände anderer Kulturen aus denselben Materialien als "Scrimshaw"-Vorläufer bezeichnet. Aus dem europäischen Mittelalter sind zwar zahlreiche Beispiele von Schnitzereien aus Walroßzahn und Walknochen bekannt, nicht jedoch aus Pottwalzahn, dem beinah stereotypen Werkstoff der "Scrimshander" des 19. und 20. Jahrhunderts. Der "Königsspiegel", ein um 1250/60 in Norwegen geschriebener pädagogischer Text, erwähnt gleichwohl Schnitzereien aus Pottwalzahn. Auch aus dem 16. und 17. Jahrhundert sind textliche Hinweise auf skandinavisches Kunstgewerbe aus den Zähnen dieses Meeressäugers bekannt. Im Anschluß an die Präsentation dieser Quellen wird ein konkretes Beispiel vorgestellt: Es handelt sich um ein beschnitztes und graviertes Salbenhorn aus Pottwalzahn, das sich in der Sammlung christlicher Kunst und Kultur des Museums der Universität Bergen, Norwegen, lnv. MA 437, befindet. Aus dem massiven Dentin wurde ein Greif herausgeschnitzt, der Ausguß wurde wie der Kopf eines gotischen Wasserspeiers gestaltet. Auf einer glatten Seitenfläche wurde später ein kleines Tondo mit Pflanzen- und Vogelmotiv eingraviert. Es trägt eine Inschrift, die vom Bergenser Museum als griechisch, hier aber als russisch identifiziert wurde, deren Sinn aber unklar bleibt. Anlass, die vom Museum vorgenommene Datierung des Zahns in das 13. Jahrhundert zu revidieren, besteht allerdings nicht

    On Bernoulli Decompositions for Random Variables, Concentration Bounds, and Spectral Localization

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    As was noted already by A. N. Kolmogorov, any random variable has a Bernoulli component. This observation provides a tool for the extension of results which are known for Bernoulli random variables to arbitrary distributions. Two applications are provided here: i. an anti-concentration bound for a class of functions of independent random variables, where probabilistic bounds are extracted from combinatorial results, and ii. a proof, based on the Bernoulli case, of spectral localization for random Schroedinger operators with arbitrary probability distributions for the single site coupling constants. For a general random variable, the Bernoulli component may be defined so that its conditional variance is uniformly positive. The natural maximization problem is an optimal transport question which is also addressed here

    On the volume functional of compact manifolds with boundary with constant scalar curvature

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    We study the volume functional on the space of constant scalar curvature metrics with a prescribed boundary metric. We derive a sufficient and necessary condition for a metric to be a critical point, and show that the only domains in space forms, on which the standard metrics are critical points, are geodesic balls. In the zero scalar curvature case, assuming the boundary can be isometrically embedded in the Euclidean space as a compact strictly convex hypersurface, we show that the volume of a critical point is always no less than the Euclidean volume bounded by the isometric embedding of the boundary, and the two volumes are equal if and only if the critical point is isometric to a standard Euclidean ball. We also derive a second variation formula and apply it to show that, on Euclidean balls and ''small'' hyperbolic and spherical balls in dimensions 3 to 5, the standard space form metrics are indeed saddle points for the volume functional

    The use of a commercial test system (SALMOTYPE ELISA) for tracing antibodies against Salmonella in the serum of pigs

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    The German Federal Ministry of Health and the Federal Ministry of Food, Agriculture and Forestry have resented guidelines for a program to reduce the introduction of Salmonella into meat production via slaughter pigs . These guidelines intend to determine the prevalence of Salmonella in farms raising slaughter pigs. For this, random samples are to be examined with a meat juice ELISA for the detection of Salmonella antibodies. In this study the use of two such ELISA systems was tested. In order to compare the commercially available SALMOTYPE ®meat juice ELISA with a meat juice ELISA developed by the German Federal Institute for Health Protection of Consumers and Veterinary Medicine (BgVV) test sera were examined in parallel via both systems. In these examinations the SALMOTYPE ® meat juice ELISA showed a higher sensitivity. Further experiments were carried out to analyze the practical applicability of the SALMOTYPE ®meat juice ELISA. Fo r this, 119 serum samples of slaughter pigs were examined with the SALMOTYPE ®meat juice ELISA. The advantages of this test system, which were already noticed in the comparison of the two test systems, like quick performance, ease of application and reliability of results, were confmned in these examinations

    On spectral minimal partitions: the case of the sphere

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    We consider spectral minimal partitions. Continuing work of the the present authors about problems for planar domains, [23], we focus on the sphere and obtain a sharp result for 3-partitions which is related to questions from harmonic analysis, in particular to a conjecture of Bishop

    High prevalence of BRCA1 stop mutation c.4183C>T in the Tyrolean population: implications for genetic testing

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    Screening for founder mutations in BRCA1 and BRCA2 has been discussed as a cost-effective testing strategy in certain populations. In this study, comprehensive BRCA1 and BRCA2 testing was performed in a routine diagnostic setting. The prevalence of the BRCA1 stop mutation c.4183C>T, p.(Gln1395Ter), was determined in unselected breast and ovarian cancer patients from different regions in the Tyrol. Cancer registry data were used to evaluate the impact of this mutation on regional cancer incidence. The mutation c.4183C>T was detected in 30.4% of hereditary BRCA1-associated breast and ovarian cancer patients in our cohort. It was also identified in 4.1% of unselected (26% of unselected triple negative) Tyrolean breast cancer patients and 6.8% of unselected ovarian cancer patients from the Lower Inn Valley (LIV) region. Cancer incidences showed a region-specific increase in age-stratified breast and ovarian cancer risk with standardized incidence ratios of 1.23 and 2.13, respectively. We, thus, report a Tyrolean BRCA1 founder mutation that correlates to a local increase in the breast and ovarian cancer risks. On the basis of its high prevalence, we suggest that targeted genetic analysis should be offered to all women with breast or ovarian cancer and ancestry from the LIV region
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