1,291 research outputs found
Phase space reduction of star products on cotangent bundles
No full textIn 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
No full textKrawczyk, R.: Intervalloperatoren einer ...; Eine Bemerkung zur Konvergenz ...; Neumaier, A.: A distributive ...SIGLEDEGerman
A note on the SSOR convergence domain due to Neumaier and Varga
No full textAbstractIn 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.
No full textThe Authors report a series of 7 patients operated for subcutaneous lesions of the quadriceps tendon using clinical, echotographic and isokinetic management
Stability and degradation of indocyanine green in plasma, aqueous solution and whole blood
No full textFluorescence-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
Color Doppler appearance of penile cavernosal-spongiosal communications in patientswith normal and impaired erection
No full textOur objective was to investigate prevalence and Doppler characteristics of penile cavernosal-spongiosal communications (CSC). These vessels are either anastomoses connecting the cavernosal arteries with the urethral arterial network or afferent vessels to the corpus spongiosum. Sixty-one consecutive patients underwent penile color Doppler US. Waveform changes in CSC were evaluated in comparison with changes in the cavernosal artery. Eighteen of 61 patients had normal erection, 17 of 61 had arterial insufficiency, and 26 of 61 had veno-occlusive dysfunction. Resistance index (RI) in CSC was significantly lower than in cavernosal arteries in all patients and increased during phases 1-2 (positive diastolic flow). Peak systolic velocity (PSV) in CSC was significantly higher in the patients with veno-occlusive dysfunction. During cavernosal phase 4 (diastolic flow reversal) CSC of patients with normal erection or with arterial insufficiency disappeared, underwent markedly reduced diastolic flow, or had systolic flow inversion. Conversely, low resistance flow was appreciable in CSC of patients with veno-occlusive dysfunction who reached phase 4. During phase 5 (systolic peak reduction) all CSC disappeared. Color Doppler US allows evaluation of CSC both in patients with normal and impaired erection
Calcific tendinitis of the rotator cuff as a cause of drooping shoulder
No full textWe describe a case of inferior glenohumeral subluxation or drooping shoulder secondary to acute calcific tendinitis of the rotator cuff. The various etiologies of drooping shoulder and the specific causes determining glenohumeral widening in our report are discussed. The importance in recognizing this uncommon complication of a common abnormal finding and correction by aspiration is stressed
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