From N-parameter fractional Brownian motions to N-parameter multifractional Brownian motions

Multifractional Brownian motion is an extension of the well-known fractional Brownian motion where the Holder regularity is allowed to vary along the paths. In this paper, two kind of multi-parameter extensions of mBm are studied: one is isotropic while the other is not. For each of these processes, a moving average representation, a harmonizable representation, and the covariance structure are given. The Holder regularity is then studied. In particular, the case of an irregular exponent function H is investigated. In this situation, the almost sure pointwise and local Holder exponents of the multi-parameter mBm are proved to be equal to the correspondent exponents of H. Eventually, a local asymptotic self-similarity property is proved. The limit process can be another process than fBm.Comment: 36 page

Analysis of operating data related to power and flow distribution in a PWR

Statement of responsibility on title-page reads: Henry C. Herbin, David D. Lanning, Neil E. Todreas, Brian W. Kirschner, [and] Alan E. Ladieu"Issued: May 1974."Substantially the same as a Nuclear Engineering thesis in the M.I.T. Dept. of Nuclear Engineering, 1974Includes bibliographical references (leaves 141-143)The analysis of the effects of the uncertainties associated with temperature and power measurements in the Connecticut Yankee Reactor leads to the evaluation of the uncertainty associated with the effective flow factor. The effective flow factor is defined as the normalized ratio of the average assembly power to the coolant temperature use in each instrumented fuel assembly. Analysis of operating data indicates that the effective flow factor is a measure of the quality of agreement between the reactor physics and the thermal hydraulic analysis of the core. The methods given are also used for the evaluation of the uncertainties associated with the peaking factors, including the results of a sensitivity analysis developed with the code INCORE. Flow calculations have been performed with the code COBRA III C. The original version of the code COBRA III C has been expanded and a method is given to easily handle any further change in the code. A sensitivity a! nalysis, using the code COBRA III C shows the weak sensitivity of the exit conditions of the coolant on most input parameters and on the inlet flow distribution of the coolant selected for the calculation. This low sensitivity indicates that the information obtained from the assembly exit thermocouple cannot be used for the determination of the cross flow pattern between the fuel assemblies

In vitro inhibition of porcine cytochrome P450 by 17β -estradiol and 17α-estradiol

Sexually mature pigs are known to possess high concentrations of testicular steroids, which have been shown to change the activities of cytochrome P450 in vitro. The aim of the present study was to evaluate the regulation of CYP1A and CYP2E1 activity by the steroids dihydrotestosterone (DHT), 3β-androstenol, 17β-estradiol and 17α-estradiol. Catalytic activities of 7-ethoxyresorufin O-deethylase (EROD) and 7-methoxyresorufin O-demethylase (MROD) were used as markers of CYP1A activities, while p-nitrophenol hydroxylase (PNPH) was used as a marker of CYP2E1 activities. Of the steroids tested, only 17β-estradiol and 17α-estradiol inhibited EROD and MROD activities. This inhibition was observed when a steroid concentration of 100 µM was used, while lower concentrations showed no inhibitory effect. PNPH activities were inhibited only by 100 µM of 17β-estradiol. The significance of these results in vivo is unknown because inhibition was only found when concentrations of estrogens higher than physiological levels were used. Nevertheless, the results provided further evidence on the important role of estrogens in regulation of porcine cytochrome P450 activities

South Atlantic paleobathymetry since early Cretaceous

We present early Cretaceous to present paleobathymetric reconstructions and quantitative uncertainty estimates for the South Atlantic, offering a strong basis for studies of paleocirculation, paleoclimate and paleobiogeography. Circulation in an initially salty and anoxic ocean, restricted by the topography of the Falkland Plateau, Rio Grande Ridge and Walvis Rise, favoured deposition of thick evaporites in shallow water of the Brazilian-Angolan margins. This ceased as sea oor spreading propagated northwards, opening an equatorial gateway to shallow and intermediate circulation. This gateway, together with subsiding volcano-tectonic barriers would have played a key role in Late Cretaceous climate changes. Later deepening and widening of the South Atlantic, together with gateway opening at Drake Passage would lead, by mid-Miocene (∼15 Ma) to the establishment of modern-style thermohaline circulation