Simón Bolívar University

About: Simón Bolívar University is a education organization based out in Caracas, Venezuela. It is known for research contribution in the topics: Population & Crystallization. The organization has 5912 authors who have published 8294 publications receiving 126152 citations.

Sharpening "Primes is in P" for a large family of numbers

Abstract: We give Deterministic Primality tests for large families of numbers. These tests were inspired in the recent and celebrated Agrawal-Kayal-Saxena (AKS) test. The AKS test has proved polynomial complexity O ((log n)^12) and they expect it to be O ((log n)^6) . Our tests have proved complexity O ((log n)^6). The complexity decreases to O ((log n)^4) as the power of 2 dividing n + 1 or n - 1 increases. On large enough primes, our tests, in their worst case, run at least 2^9 times faster than the AKS test.

Using the empirical moment generating function in testing for the Weibull and the type I extreme value distributions

Abstract: We introduce two families of statistics, functionals of the empirical moment generating function process of the logarithmically transformed data, for testing goodness of fit to the two-parameter Weibull distribution or, equivalently, to the type I extreme value model. We show that when affine invariant estimators are used for the parameters of the extreme value distribution, the distributions of these statistics do not depend on the underlying parameters and one of them has a limiting chi-squared distribution. We estimate, via simulations, some finite sample quantiles for the statistics introduced and evaluate their power against a varied set of alternatives.

Electroreduction of chloroacetic acids (mono-, di- and tri-) at polyNi(II)-tetrasulfonated phthalocyanine gold modified electrode

Abstract: The electroformation of polyNi(II)-tetrasulfonated phthalocyanine (poly-NiTSPC) film, on gold electrodes from an alkaline solution was investigated in order to improve the electrochemical detection of haloacetic acids (mono-, di- and tri-chloroacetic). The data obtained were compared to those obtained at bare Au electrode. The electrocatalytic activity of the poly-NiTSPC towards the chloroacetic acids reduction, promotes a negative shift of the peak potential (by ca. 250 mV) and an increase of the current intensity (by ca. 25%) compared to bare Au electrode. The concentration of chloride-ion in solution was obtained during electrolysis for each chloroacetic acid; and the number of electrons involved in haloacetic acids reduction and heterogeneous rate constant (k) were evaluated by rotating disk electrode (RDE). These studies showed that the mechanism of catalytic reduction of chloroacetic acids can be expressed on the basis that the current-determining step in the electroreduction of chloroacetate ions must involve the removal of a halogen atom from the anion. The modified electrode showed an excellent sensitivity and detection limit towards haloacetic acid reduction.