197,240 research outputs found

    Phase space reduction of star products on cotangent bundles

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    In this paper we construct star products on Marsden-Weinstein reduced spaces in case both the original phase space and the reduced phase space are (symplectomorphic to) cotangent bundles. Under the assumption that the original cotangent bundle T∗Q carries a symplectic structure of form ωB0 = ω0 +π∗B0 with B0 a closed two-form on Q, is equipped by the cotangent lift of a proper and free Lie group action on Q and by an invariant star product that admits a G-equivariant quantum momentum map, we show that the reduced phase space inherits from T∗Q a star product. Moreover, we provide a concrete description of the resulting star product in terms of the initial star product on T∗Q and prove that our reduction scheme is independent of the characteristic class of the initial star product. Unlike other existing reduction schemes we are thus able to reduce not only strongly invariant star products. Furthermore in this article, we establish a relation between the characteristic class of the original star product and the characteristic class of the reduced star product and provide a classification up to G-equivalence of those star products on (T∗Q, ωB0 ), which are invariant with respect to a lifted Lie group action. Finally, we investigate the question under which circumstances ‘quantization commutes with reduction’ and show that in our examples non-trivial restrictions arise

    Intervalloperatoren einer Funktion, deren Lipschitzmatrix eine M-Intervallmatrix ist. Eine Bemerkung zur Konvergenz von Intervallfolgen

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    Krawczyk, R.: Intervalloperatoren einer ...; Eine Bemerkung zur Konvergenz ...; Neumaier, A.: A distributive ...SIGLEDEGerman

    A note on the SSOR convergence domain due to Neumaier and Varga

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    AbstractIn a recent paper A. Neumaier and R. S. Varga show that if A is an n ×ncomplex H-matrix with 12 < ϱ(∣JA∣) < 1, then ϱ(SAω) < 1 for all 0 < ω < g̃w:=2/ (1 + √2ϱ(∣JA∣) − 1), where SAω and JA are, respectively, the symmetric successive overrelaxation (SSOR) iteration matrix and the Jacobi iteration matrix associated with A. We show that ϱ(SAg̃w) < 1. This allows us to also sharpen further results on the SSOR method for H-matrices due to Varga, Niethammer, and Cai

    Considerazioni sulle lacerazioni sottocutanee del tendine del quadricipite.

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    The Authors report a series of 7 patients operated for subcutaneous lesions of the quadriceps tendon using clinical, echotographic and isokinetic management

    Dr. Duane M. Jackson, Morehouse College, July 2011

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    This video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer

    "Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.

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    "Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states. By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement. To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports

    Stability and degradation of indocyanine green in plasma, aqueous solution and whole blood

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    Fluorescence-based imaging has evolved into an important technology during recent years. Specifically indocyanine green (ICG) has invaded most fields of diagnostic and interventional medicine. Considering the numerous advantages of the substance like the rapid degradation and rare adverse reactions, ICG is currently the most commonly used fluorescing agent. High-performance liquid chromatography (HPLC) was used for measuring absorbance and fluorescence of ICG and its potential degradation compounds. Stability and degradation were evaluated under light exposure or in darkness at various temperatures. Under these conditions, degradation of ICG was evaluated over a period of 11 days. Additional, stability measurements of ICG were performed in EDTA whole blood samples at 37 °C incubation temperature while monitoring. Furthermore, we used mass spectrometric (MS) and nuclear magnetic resonance (NMR) analyses for the identification of supposed ICG degradation compound. Potential quenching effect of ICG was examined in aqueous and plasma solutions at concentrations ranging from 0.01-100 μg ml-1. When diluted in water and stored at 4 °C in the dark, ICG is stable for three days with only 20% of fluorescence intensity lost in this time-span. ICG incubated at 37 °C in whole blood under light exposure is stable for 5 h. In our study we observed the degradation of ICG into two degradation compounds with a mass of m/z 785.32 and m/z 1501.57, respectively. Based on our observations we suggest that ICG should be used within one or two days after preparation, if the ICG solution is stored at 4 °C
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