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41.
This paper presents empirical evidence of long range dependence in returns and volatility for banking indices for 41 different countries. We employ the Rescaled Hurst analysis and develop a formal statistical procedure to test for long range dependence. This procedure allows to rank these countries by relative inefficiency, which can provide guidance for investors and portfolio managers. 相似文献
42.
Paul A. Milewski Esteban G. Tabak Eric Vanden-Eijnden 《Studies in Applied Mathematics》2002,108(1):123-144
A new model for studying energy transfer is introduced. It consists of a "resonant duo"—a resonant quartet where extra symmetries support a reduced subsystem with only two degrees of freedom—where one mode is forced by white noise and the other is damped. This system has a single free parameter: the quotient of the damping coefficient to the amplitude of the forcing times the square root of the strength of the nonlinearity. As this parameter varies, a transition takes place from a Gaussian, high-temperature, near equilibrium regime, to one highly intermittent and non-Gaussian. Both regimes can be understood in terms of appropriate Fokker–Planck equations. 相似文献
43.
V. S. Troitskaya V. G. Vinokurov I. I. Grandberg S. V. Tabak 《Chemistry of Heterocyclic Compounds》1969,3(4):256-263
The IR spectra of the previously synthesized pyrazolo[3,4-b]- and pyrazolo [4, 5-b] pyridones are investigated. From analysis of the IR spectra of the pyrazolopyridones themselves, and of complexes with heavy metal salts, as well as of some model compounds, conclusions are drawn regarding their lactam structure.For Part LI see [20]. 相似文献
44.
The interaction of the cationic meso-tetrakis 4-N-methylpyridyl porphyrin (TMPyP) with large unilamellar vesicles (LUVs) was investigated in the present study. LUVs were formed by mixtures of the zwitterionic 1,2-dipalmitoyl-sn-glycero-phosphatidylcholine (DPPC) and anionic 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) phospholipids, at different DPPG molar percentages. All investigations were carried out above (50 °C) and below (25 °C) the main phase transition temperature of the LUVs (~41 °C). The binding constant values, K(b), estimated from the time-resolved fluorescence study, showed a significant increase of the porphyrin affinity at higher mol% DPPG. This affinity is markedly increased when the LUVs are in the liquid crystalline state. For both situations, the increase of the K(b) value was also followed by a higher porphyrin fraction bound to the LUVs. The displacement of the vesicle-bound porphyrins toward the aqueous medium, upon titration with the salt potassium chloride (KCl), was also studied. Altogether, our steady-state and frequency-domain fluorescence quenching data results indicate that the TMPyP is preferentially located at the LUVs Stern layer. This is supported by the zeta potential studies, where a partial neutralization of the LUVs surface charge, upon porphyrin titration, was observed. Dynamic light scattering (DLS) results showed that, for some phospholipid systems, this partial neutralization leads to the LUVs flocculation. 相似文献
45.
T. V. Panekina S. D. Gusakova M. Ya. Tabak A. U. Umarov 《Chemistry of Natural Compounds》1978,14(1):33-36
Summary From the sum of the neutral lipids of the seeds ofE. moluccelloides we have isolated the natural di-and monoglycerides, have determined their structure, and have established that these classes of lipids contain a higher amount of saturated acids in the position than the triglycerides of the seeds.It has also been established that in the hydrolysis of natural diglycerides with the nonspecific lipase of the fungusO. lactis synthetic triglycerides are formed that differ from natural triglycerides by an increased amount of saturated acids.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Microbiology Division of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 44–48, January–February, 1978. 相似文献
46.
Hidalgo AA Pimentel AS Tabak M Oliveira ON 《The journal of physical chemistry. B》2006,110(39):19637-19646
An investigation has been made of the interaction between chlorpromazine (CPZ) and monolayers of 1,2-dipalmitoyl-sn-3-glycerophosphatidylcholine (DPPC) and 1,2-dipalmitoyl-sn-3-glycero[phospho-rac-(1-glycerol)] (DPPG), both at the air/water interface and in transferred Langmuir-Blodgett films. The Gibbs free energy, DeltaG, and the compressibility modulus (C(S)(-1)), obtained from the surface pressure isotherms, indicated changes in the in-plane interactions of CPZ/DPPG mixed monolayers, with positive values of DeltaG. The arrangement of CPZ in the zwitterionic DPPC monolayers causes a weaker interaction in CPZ/DPPC mixed monolayers, with the DeltaG fluctuating around zero. IR measurements in transferred monolayers showed that CPZ did not affect the conformational order of the acyl chains, its effects being limited to the bands corresponding to the headgroups. Furthermore, since no shift was observed for the acyl chain bands, the phase transition induced by CPZ is not a liquid expanded (LE) to liquid condensed (LC) transition, as the latter is associated with chain ordering. Taken together, the IR and compressibility results demonstrate that the effect from CPZ cannot be correlated with temperature changes in the subphase for pure monolayers, in contrast to models proposed by other authors. 相似文献
47.
Corti M. Faffa F. Rigamonti A. Tabak F. Carretta P. Licci F. Raffo L. 《Il Nuovo Cimento D》1994,16(10):1793-1797
Il Nuovo Cimento D - 139La NQR spectra, μSR precessional frequencies and NQR relaxation rates W driven by the Cu2+ spin fluctuations are used to study the static magnetic properties and the... 相似文献
48.
Santiago PS Neto Dde S Gandini SC Tabak M 《Colloids and surfaces. B, Biointerfaces》2008,65(2):247-256
Fluorescence quenching of meso-tetrakis-4-sulfonatophenyl (TPPS(4)) and meso-tetrakis-4-N-methylpyridil (TMPyP) porphyrins is studied in aqueous solution and upon addition of micelles of sodium dodecylsulfate (SDS), cetyltrimethylammonium chloride (CTAC), N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS) and t-octylphenoxypolyethoxyethanol (Triton X-100). Potassium iodide (KI) was used as quencher. Steady-state Stern-Volmer plots were best fitted by a quadratic equation, including dynamic (K(D)) and static (K(S)) quenching. K(S) was significantly smaller than K(D). Frequency-domain fluorescence lifetimes allowed estimating bimolecular quenching constants, k(q). At 25 degrees C, in aqueous solution, TMPyP shows k(q) values a factor of 2-3 higher than the diffusional limit. TPPS(4) shows collisional quenching with pH dependent k(q) values. For TMPyP quenching results are consistent with reported binding constants: a significant reduction of quenching takes place for SDS, a moderate reduction is observed for HPS and almost no change is seen for Triton X-100. Similar data were obtained at 50 degrees C. For CTAC-TPPS(4) system an enhancement of quenching was observed as compared to pure buffer. This is probably associated to accumulation of iodide at the cationic micellar interface. The attraction between CTAC headgroups and I(-), and repulsion between SDS and I(-), enhances and reduces the fluorescence quenching, respectively, of porphyrins located at the micellar interface. The small quenching of TPPS(4) in Triton X-100 is consistent with strong binding as reported in the literature. 相似文献
49.
Li CK Séguin FH Frenje JA Rygg JR Petrasso RD Town RP Amendt PA Hatchett SP Landen OL Mackinnon AJ Patel PK Tabak M Knauer JP Sangster TC Smalyuk VA 《Physical review letters》2007,99(1):015001
Monoenergetic proton radiography was used to make the first measurements of the long-time-scale dynamics and evolution of megagauss laser-plasma-generated magnetic field structures. While a 1-ns 10(14) W/cm2 laser beam is on, the field structure expands in tandem with a hemispherical plasma bubble, maintaining a rigorous 2D cylindrical symmetry. With the laser off, the bubble continues to expand as the field decays; however, the outer field structure becomes distinctly asymmetric, indicating instability. Similarly, localized asymmetry growth in the bubble interior indicates another kind of instability. 2D LASNEX hydrosimulations qualitatively match the cylindrically averaged post-laser plasma evolution but even then it underpredicts the field dissipation rate and of course completely misses the 3D asymmetry growth. 相似文献
50.
Luciano Zunino Alejandra Figliola Benjamin M. Tabak Darío G. Prez Mario Garavaglia Osvaldo A. Rosso 《Chaos, solitons, and fractals》2009,41(5):2331-2340
We study the multifractal nature of daily price and volatility returns of Latin-American stock markets employing the multifractal detrended fluctuation analysis. Comparing with the results obtained for a developed country (US) we conclude that the multifractality degree is higher for emerging markets. Moreover, we propose a stock market inefficiency ranking by considering the multifractality degree as a measure of inefficiency. Finally, we analyze the sources of multifractality quantifying the contributions of two factors, the long-range correlations of the time series and the broad fat-tail distributions. We find that the multifractal structure of Latin-American market indices can be mainly attributed to the latter. 相似文献