A semilinear elliptic system involving nonlinear boundary condition and sign-changing weight function

AbstractIn this paper, we study the combined effect of concave and convex nonlinearities on the number of solutions for a semilinear elliptic system (Eλ,μ) involving nonlinear boundary condition and sign-changing weight function. With the help of the Nehari manifold, we prove that the system has at least two nontrivial nonnegative solutions when the pair of the parameters (λ,μ) belongs to a certain subset of R2

Inhibitory effect of rhubarb on intestinal α-glucosidase activity in type 1 diabetic rats

Purpose: To investigate the inhibitory effect of rhubarb on α-glucosidase activity in the small intestine of rats with type 1 diabetes.Methods: Type 1 diabetic rat model was established by intraperitoneally injecting 30 male SD rats with 1 % streptozocin (STZ). Rats with fasting blood glucose > 11 mmol/L (24) were used for the study. The rats were randomly divided into three equal groups including control, acarbose and rhubarb groups. Arcabose® (20 mg/kg /day) and rhubarb (100 mg/kg /day) were given by intra-gastric route via insertion of the cannula through the esophagus. Daily fasting blood glucose and daily postprandial glucose levels were assayed for all groups. On day 6, postprandial blood glucose, blood levels of C-peptide and insulin, and intestinal α-glucosidase were also determined.Results: There were no significant differences in levels of C-peptide, insulin and fasting blood glucose between control, Acarbose® and rhubarb groups (p > 0.05). However, α-glucosidase activity at 0, 30, 60 and 120 min in the rhubarb group was 1759.2, 1812.8, 1379.8 and 772.1 U, respectively,) while in the Acarbose® group it was 178.6, 1260.1, 1126.5, 599.2 U, respectively. α-Glucosidase activity in both groups initially showed an increase (p < 0.05), followed by a decline from 60 to 120 min (p ˂ 0.05). After 120 min, α-glucosidase activity in each of the two groups was significantly decreased compared with untreated control (1200 U) (p ˂ 0.05).Conclusion: The inhibitory effect of rhubarb on intestinal α-glucosidase activity of Type 1 diabetic rats is comparable to that of Arcabose®.This suggests that this plant may have clinically potent anti-diabetic properties.Keywords: Type 1 diabetes, α-Glucosidase activity, Acarbose®, Rhubarb, Postprandial glucose leve

From Yang-Mills Lagrangian to MHV Diagrams

We prove the equivalence of a recently suggested MHV-formalism to the standard Yang-Mills theory. This is achieved by a formally non-local change of variables. In this note we present the explicit formulas while the detailed proofs are postponed to a future publication.Comment: Latex,11 pages, minor changes, reference added, version to appear in JHE

BES3 time of flight monitoring system

A Time of Flight monitoring system has been developed for BES3. The light source is a 442-443 nm laser diode, which is stable and provides a pulse width as narrow as 50 ps and a peak power as large as 2.6 W. Two optical-fiber bundles with a total of 512 optical fibers, including spares, are used to distribute the light pulses to the Time of Flight counters. The design, operation, and performance of the system are described.Comment: 8 pages 16 figures, submitted to NI

Anti-Collusion Fingerprinting for Multimedia

Digital fingerprinting is a technique for identifyingusers who might try to use multimedia content for unintendedpurposes, such as redistribution. These fingerprints are typicallyembedded into the content using watermarking techniques that aredesigned to be robust to a variety of attacks. A cost-effectiveattack against such digital fingerprints is collusion, whereseveral differently marked copies of the same content are combinedto disrupt the underlying fingerprints. In this paper, weinvestigate the problem of designing fingerprints that canwithstand collusion and allow for the identification of colluders.We begin by introducing the collusion problem for additiveembedding. We then study the effect that averaging collusion hasupon orthogonal modulation. We introduce an efficient detectionalgorithm for identifying the fingerprints associated with Kcolluders that requires O(K log(n/K)) correlations for agroup of n users. We next develop a fingerprinting scheme basedupon code modulation that does not require as many basis signalsas orthogonal modulation. We propose a new class of codes, calledanti-collusion codes (ACC), which have the property that thecomposition of any subset of K or fewer codevectors is unique.Using this property, we can therefore identify groups of K orfewer colluders. We present a construction of binary-valued ACCunder the logical AND operation that uses the theory ofcombinatorial designs and is suitable for both the on-off keyingand antipodal form of binary code modulation. In order toaccommodate n users, our code construction requires onlyO(sqrt{n}) orthogonal signals for a given number of colluders.We introduce four different detection strategies that can be usedwith our ACC for identifying a suspect set of colluders. Wedemonstrate the performance of our ACC for fingerprintingmultimedia and identifying colluders through experiments usingGaussian signals and real images.This paper has been submitted to IEEE Transactions on Signal Processing</I

Roughness Signature of Tribological Contact Calculated by a New Method of Peaks Curvature Radius Estimation on Fractal Surfaces

This paper proposes a new method of roughness peaks curvature radii calculation and its application to tribological contact analysis as characteristic signature of tribological contact. This method is introduced via the classical approach of the calculation of radius of asperity. In fact, the proposed approach provides a generalization to fractal profiles of the Nowicki's method [Nowicki B. Wear Vol.102, p.161-176, 1985] by introducing a fractal concept of curvature radii of surfaces, depending on the observation scale and also numerically depending on horizontal lines intercepted by the studied profile. It is then established the increasing of the dispersion of the measures of that lines with that of the corresponding radii and the dependence of calculated radii on the fractal dimension of the studied curve. Consequently, the notion of peak is mathematically reformulated. The efficiency of the proposed method was tested via simulations of fractal curves such as those described by Brownian motions. A new fractal function allowing the modelling of a large number of physical phenomena was also introduced, and one of the great applications developed in this paper consists in detecting the scale on which the measurement system introduces a smoothing artifact on the data measurement. New methodology is applied to analysis of tribological contact in metal forming process

Measurement of Ultra-Low Potassium Contaminations with Accelerator Mass Spectrometry

Levels of trace radiopurity in active detector materials is a subject of major concern in low-background experiments. Among the radio-isotopes, \k40 is one of the most abundant and yet whose signatures are difficult to reject. Procedures were devised to measure trace potassium concentrations in the inorganic salt CsI as well as in organic liquid scintillator (LS) with Accelerator Mass Spectrometry (AMS), giving, respectively, the \k40-contamination levels of $\sim 10^{-10}$ and $\sim 10^{-13}$ g/g. Measurement flexibilities and sensitivities are improved over conventional methods. The projected limiting sensitivities if no excess of potassium signals had been observed over background are $8 \times 10^{-13}$ g/g and $3 \times 10^{-17}$ g/g for the CsI and LS, respectively. Studies of the LS samples indicate that the radioactive contaminations come mainly in the dye solutes, while the base solvents are orders of magnitude cleaner. The work demonstrate the possibilities of measuring naturally-occurring isotopes with the AMS techniques.Comment: 18 pages, 4 figures, 3 table

Real-time visualization of a sparse parametric mixture model for BTF rendering

Bidirectional Texture Functions (BTF) allow high quality visualization of real world materials exhibiting complex appearance and details that can not be faithfully represented using simpler analytical or parametric representations. Accurate representations of such materials require huge amounts of data, hindering real time rendering. BTFs compress the raw original data, constituting a compromise between visual quality and rendering time. This paper presents an implementation of a state of the art BTF representation on the GPU, allowing interactive high fidelity visualization of complex geometric models textured with multiple BTFs. Scalability with respect to the geometric complexity, amount of lights and number of BTFs is also studied.Fundação para a Ciência e Tecnologi