A stochastic model for localized disturbances and its applications

A stochastic model for local disturbances, particularly for a temporal harmonic with random modulations in amplitude and/or phase, is proposed in this paper. Results for the second moment responses of a linear single-degree-of-freedom system to this type of stochastic loading demonstrate a significant change in response characteristics due to a small uncertainty. A local phenomenon may last much longer and resonance may be smeared to a broad range. Integrated with wavelet transform, the proposed approach may be used to model a random process with non-stationary frequency content. Especially, it can be effectively used for Monte Carlo simulation to generate large size of samples that have similar characteristics in time and frequency domains as a pre-selected mother sample has. The technique has a great potential for the case where uncertainty study is warranted but the available samples are limited.     

Profiling Voids Embedded in a Slab by a Non-Linear Model

In this paper, by applying a non linear model for the electromagnetic inverse scattering, a technique for the dielectric profiling of a planarly layered medium is investigated and applied to void localization and diagnostics inside a homogeneous lossless slab (one-dimensional geometry). Data are collected under plane wave multifrequency normal incidence. Suitable finite dimensional representations for the unknown functions are introduced and their influence on the model is discussed. The resulting functional equation is solved by the method of weighted residuals and the solution algorithm amounts to minimizing a non quadratic function, where particular attention is devoted to reduce the occurrence of local minima. Finally, the inversion algorithm is validated by applications to both simulated and experimental data.     

Hydrogen adsorption studies in micro-size cobalt dots

Hydrogen desorption curves were obtained from a sample composed of a square arrangement of Co dots with average diameter of 4.4 μm, separated by a distance of 11.6 μm. A macroscopic sample of Co dots grown on a 2.5 × 2.5 cm Si substrate was made by standard lithographic techniques and used in these experiments. Thermal programmed desorption (TPD) was performed under ultra-high vacuum conditions. Hydrogen TPD curves were obtained from a 1 × 1 cm Co dots samples displaying a maximum of intensity at 425 K. Hydrogen TPD curve was also obtained from 1 cm× 1 cm samples of Co films and Co foils for comparison. The hydrogen TPD curves have decreasing intensity from the Co foils to the Co dots and finally to the Co films. This indicates that there are more sites for hydrogen adsorption on the Co dots than in the Co films. This is a surprising result because there is approximately 8.7 times less Co atoms exposed in the Co dots that in the Co film sample. A desorption energy of 27 kcal/mol was obtained for the Co dots suggesting that hydrogen is adsorbed on an hcp hollow site of the Co dot crystalline structure.     

Lithiasis of the prostatic loge

Lithiasis may develop in the prostate loge following prostate surgery. Calculus formation in the prostate can be ascribed basically to foreign bodies, residual adenomatous spheroids and clots or fragments of sphacelous mucosa in the presence of a stenotic area after surgery and/or infection. The diagnosis is based on the physical examination and particularly on the radiological findings. Treatment is by open surgery or endoscopic or extracorporeal lithotripsy.     

In-laboratory removal of femoral sheath following protamine administration in patients having intracoronary stent implantation

Two hundred twenty-eight patients with successful coronary stent implantation were randomized either to protamine administration and femoral sheath removal (group I, n = 117) or no heparin neutralization and delayed sheath removal (group II, n = 111). The hospital stay after treatment was shorter in patients receiving protamine; therefore, protamine use for neutralizing circulating heparin may be safely administered immediately after stent implantation.     

Membrane-bound calmodulin in Xenopus laevis oocytes as a novel binding site for melatonin

Melatonin has been suggested as a physiological antagonist of calmodulin. In this work, we have characterized melatonin binding sites in Xenopus laevis oocyte membranes. Binding of [125I]melatonin by X. laevis oocyte membranes fulfills all criteria for binding to a receptor site. Binding was dependent on time, temperature, and membrane concentration and was stable, reversible, saturable, and specific. The binding site was also pharmacologically characterized. Stoichiometric studies showed a high-affinity binding site with a Kd of 1.18 nM. These data are in close agreement with data obtained from kinetic studies (Kd=0.12 nM). In competition studies, we observed a low-affinity binding site (Kd=63.41 microM). Moreover, the binding site was characterized as calmodulin. Thus, binding was dependent on calcium and blocked by anti-CaM antibodies in a concentration-dependent manner. Calmodulin inhibitor chlorpromazine also inhibited binding of the tracer. From these results, it is suggested that membrane-bound calmodulin acts as a melatonin binding site in Xenopus laevis oocytes, where it might couple cellular activities to rhythmic circulating levels of melatonin. This hypothesis correlates with the previous findings describing melatonin as a physiological antagonist of calmodulin.     

A short-term longitudinal study of impulsivity and antisocial behavior.

Analyzes the relationships between impulsivity and antisocial behavior in a noninstitutionalized sample, taking into account the multidimensional nature of impulsivity and the diversity of types of antisocial behavior. Data were obtained in 1989 and 1990 from 1,226 adolescents aged 12–18 yrs as part of a longitudinal study of risk factors for drug abuse and delinquency. The patterns of stability or change of the various dimensions of antisocial behavior (rule breaking, vandalism, theft, aggression, and drug taking) in relation to impulsivity were investigated. The results support that self-report measures of impulsivity are closely correlated with antisocial behavior among adolescents. The longitudinally-oriented analysis of this work also shows that impulsivity is associated with a future increase in antisocial behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Protecting against key-exposure: strongly key-insulated encryption with optimal threshold

Key-insulated encryption schemes use a combination of key splitting and key evolution to protect against key exposure. Existing schemes, however scale poorly, having cost proportional to the number t of time periods that may be compromised by the adversary, and thus are practical only for small values of t. Yet in practice t might be large. This paper presents a strongly key-insulated encryption scheme with optimal threshold. In our scheme, t need not be known in advance and can be as large as one less than the total number of periods, yet the cost of the scheme is not impacted. This brings key-insulated encryption closer to practice. Our scheme is based on the Boneh-Franklin identity-based encryption (IBE) scheme [9], and exploits algebraic properties of the latter. Another contribution of this paper is to show that (not strongly) key-insulated encryption with optimal threshold and allowing random-access key updates (which our scheme and all others known allow) is equivalent to a restricted form of IBE. This means that the connection between key-insulated encryption and IBE is not accidental. Supported in part by NSF grants CCR-0098123, ANR-0129617 and CCR-0208842, and by an IBM Faculty Partnership Development Award. Supported in part by an NSF graduate fellowship.