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51.
We investigate the commutation between a continuous linear random operator and a continuous linear deterministic operator on a Banach space. From this we obtain probabilistic versions of theorems by Fuglede and Putnam, both of them dealing with the commutation between continuous linear operators with continuous normal operators on a Hilbert space.  相似文献   
52.
Only few efforts have been made in order to relax one of the key assumptions of the Black-Scholes model: the no-arbitrage assumption. This is despite the fact that arbitrage processes usually exist in the real world, even though they tend to be short-lived. The purpose of this paper is to develop an option pricing model with endogenous stochastic arbitrage, capable of modelling in a general fashion any future and underlying asset that deviate itself from its market equilibrium. Thus, this investigation calibrates empirically the arbitrage on the futures on the S&P 500 index using transaction data from September 1997 to June 2009, from here a specific type of arbitrage called “arbitrage bubble”, based on a t-step function, is identified and hence used in our model. The theoretical results obtained for Binary and European call options, for this kind of arbitrage, show that an investment strategy that takes advantage of the identified arbitrage possibility can be defined, whenever it is possible to anticipate in relative terms the amplitude and timespan of the process. Finally, the new trajectory of the stock price is analytically estimated for a specific case of arbitrage and some numerical illustrations are developed. We find that the consequences of a finite and small endogenous arbitrage not only change the trajectory of the asset price during the period when it started, but also after the arbitrage bubble has already gone. In this context, our model will allow us to calibrate the B-S model to that new trajectory even when the arbitrage already started.  相似文献   
53.

Background  

Inflammation around cell bodies of primary sensory neurons and retinal ganglion cells enhances expression of neuronal growth-associated genes and stimulates axonal regeneration. We have asked if inflammation would have similar effects on corticospinal neurons, which normally show little response to spinal cord injury. Lipopolysaccharide (LPS) was applied onto the pial surface of the motor cortex of adult rats with or without concomitant injury of the corticospinal tract at C4. Inflammation around corticospinal tract cell bodies in the motor cortex was assessed by immunohistochemistry for OX42 (a microglia and macrophage marker). Expression of growth-associated genes c-jun, ATF3, SCG10 and GAP-43 was investigated by immunohistochemistry or in situ hybridisation.  相似文献   
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We investigate the closability of those derivations D definedon a (non necessarily closed) subalgebra B of a complex Banachalgebra A for which the conditions BABB and dim[BkRad(A)]< hold for some kN, where Rad(A) stands for the Jacobson radicalof A. In this situation we show that the separating subspaceY(D) for D satisfies the property B[BY(D)]BRad(A). Furthermore, we demonstrate several specially relevant situationsin which we get a ‘closability property’ which ismore precise than the former one.  相似文献   
57.
Let T be a continuous linear operator on a Banach algebra A. We address the question of whether the constant ${{\rm sup}\{||aT(b)c||: a, b, c \in A, \, ab = bc = 0, ||a|| = ||b|| = ||c||=1\}}Let T be a continuous linear operator on a Banach algebra A. We address the question of whether the constant sup{||aT(b)c||: a, b, c ? A,  ab = bc = 0, ||a|| = ||b|| = ||c||=1}{{\rm sup}\{||aT(b)c||: a, b, c \in A, \, ab = bc = 0, ||a|| = ||b|| = ||c||=1\}} being small implies that the distance from T to the space Der(A) of all continuous derivations on A is small. We show that this is the case for amenable group algebras. As a consequence, we deduce that Der(L 1(G)) is hyperreflexive for each amenable group in [SIN].  相似文献   
58.
We show that an n-homogeneous polynomial P   on the Fourier algebra A(G)A(G) of a locally compact group G   can be represented in the form P(f)=〈T,fnP(f)=T,fn(f∈A(G))(fA(G)) for some T   in the group von Neumann algebra VN(G)VN(G) of G if and only if it is orthogonally additive and completely bounded.  相似文献   
59.
In this work, the antioxidant activity of the hydro-ethanolic extracts of the leaves, flowers, and aerial parts of Steiractinia aspera Cuatrec, both fresh and post-distillation, was evaluated by ABTS, FRAP, H2O2 and DPPH assays. The cytotoxic activity was evaluated in MCF-7, MCF-10A and HT-29 cell lines. The hydro-ethanolic extracts were obtained by matrix solid-phase dispersion (MSPD) and ultrasound-assisted solvent extraction (SE). The fresh-leaf MSPD extract had the highest antioxidant activity, and the post-distillation leaf ultrasound-assisted SE extract had the highest cytotoxicity in the MCF-7 breast cancer cell line, although not selective, which was evaluated by sulforhodamine B assay. On the other hand, ROS was evaluated by flow cytometry which showed that post-distillation leaf extract is pro-oxidant. Chlorogenic acid, kaempferol-3-glucoside and quercetin were found in the fresh leaves’ extracts, according to HPLC-DAD. PLC-DAD permitted the isolation of p-coumaric acid, E-3-(4-(((E)-3-(3,4-dihydroxyphenyl) acryloyl) oxy)-3-hydroxyphenyl) acrylic acid and a diglucosylated derivative of ursolic acid, which were analyzed by 1H and 13C NMR. Our results suggest that the fresh leaf extract of Steiractinia aspera Cuatrec has potential use for antioxidant applications.  相似文献   
60.
The electroanalytical behavior of the reduction of the herbicides aziprotryne (2-azido-4-isopropylamino-6-methylthio-1,3,5-triazine) and desmetryne (4-isopropylamino-6-methylamino-2-methylthio-1,3,5-triazine) in oil-in-water emulsions is reported. This medium allows the differential pulse polarographic determination of these s-triazines directly from their sample extracts in an appropriate organic solvent. Sodium pentanesulfonate was chosen as the most suitable surfactant to be used as emulsifying agent, whereas ethyl acetate was selected as the organic solvent to form the emulsions. The peak current was maximum in a 0.3 mol L–1 HClO4 medium of the continuous aqueous phase for aziprotryne, and at pH 3.0 for desmetryne, and the potential became more negative as the pH increased for both herbicides. The limiting current is diffusion controlled and the electrode process is irreversible. Four electrons are involved in the overall electrochemical reduction process as determined by controlled potential coulometry, whereas the αna values suggested that two electrons are involved in the rate-determining step. Using differential pulse polarography, aziprotryne and desmetryne can be determined in the emulsified medium over the concentration ranges 1.0 · 10–7–1.0 · 10–4 mol L–1, with limits of detection of 4.5 · 10–8 mol L–1 and 6.6 · 10–8 mol L–1, respectively. The method was applied to the determination of aziprotryne and desmetryne in spiked irrigation water. At concentration levels of 6.0 · 10–7 mol L–1 aziprotryne and 4.0 · 10–7 mol L–1 desmetryne, recoveries of 94 ± 3% and 94 ± 4%, respectively, were obtained after preconcentration on Sep-Pack C18 cartridges. Finally, partial least-squares regression (PLSR) has been used for treatment of the polarographic data obtained from mixtures of aziprotryne, desmetryne and simazine in oil-in-water emulsions. The size of the calibration set was of 29 samples by ninety two current measurements at different potentials. Prediction of the herbicides concentration within the range 1.0 · 10–6 –1.0 · 10–5 mol L–1 was possible.  相似文献   
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