A cross-sectional survey was conducted on a sample of 1,061 students to determine the epidemiological profile of drug abuse among elementary and high school students in the State public school system in Greater Metropolitan Cuiaba, Mato Grosso, Brazil, in 1995. Results showed drug abuse among both male and female students (27. 2% and 24.1%, respectively). Drug abuse was more common in students over 18 years of age (27.1%), with grade/age discrepancies (70.7%), with higher classroom absenteeism (44.6%), and with higher social economic levels (A+B=34.5%). The most frequently abused drugs among male students were alcohol (81.8%), solvents (18.6%), and marijuana (6.0%). Early alcohol abuse was also common (12.1 +/-3.6 years). In addition to alcohol (78.6%) and tobacco (29.0%), the substances most commonly consumed by students were solvents (14.9%), anxiolytics (6. 0%), and amphetamines (4.8%). The 1995 epidemiological profile of drug abuse among elementary and high school students in the State public school system in Cuiaba was similar data from nationwide surveys conducted in 1987, 1989, and 1993.

In this work we present a theory of the multilayer perceptron from the perspective of functional analysis and variational calculus. Within this formulation, the learning problem for the multilayer perceptron lies in terms of finding a function which is an extremal for some functional. As we will see, a variational formulation for the multilayer perceptron provides a direct method for the solution of general variational problems, in any dimension and up to any degree of accuracy. In order to validate this technique we use a multilayer perceptron to solve some classical problems in the calculus of variations.The Kingdom you see is Carthage, the Tyrians, the town of Agenor; But the country around is Libya, no folk to meet in war. Dido, who left the city of Tyre to escape her brother, Rules here-a long a labyrinthine tale of wrong Is hers, but I will touch on its salient points in order... Dido, in great disquiet, organised her friends for escape. They met together, all those who harshly hated the tyrant Or keenly feared him: they seized some ships which chanced to be ready... They came to this spot, where to-day you can behold the mighty Battlements and the rising citadel of New Carthage, And purchased a site, which was named 'Bull's Hide' after the bargain By which they should get as much land as they could enclose with a bull's hide.Despite the circle appears to be an obvious solution to Dido's problem, proving this fact is rather difficult. Zenodorus proved that the area of the circle is larger

SUMMARYIn this work a conceptual theory of neural networks (NNs) from the perspective of functional analysis and variational calculus is presented. Within this formulation, the learning problem for the multilayer perceptron lies in terms of finding a function, which is an extremal for some functional. Therefore, a variational formulation for NNs provides a direct method for the solution of variational problems.This proposed method is then applied to distinct types of engineering problems. In particular a shape design, an optimal control and an inverse problem are considered. The selected examples can be solved analytically, which enables a fair comparison with the NN results.

According to the different phases at which titanium dioxide (TiO2) crystallizes, previous studies have shown that anatase is more efficient for photocatalysis than rutile. Nowadays, the synergetic effect is well-accepted between anatase and rutile as having an effect in increasing performance in photocatalysis. In the present work, control over the anatase/rutile ratio was performed in three experimental steps. Initially, amorphous-anatase TiO2 powders were synthesized by the sol-gel method. For the crystallization of anatase, the powders were annealed at 250 °C for 2 h in ambient atmosphere. The final step was performed by using different annealing times, ranging from 35 up to 200 min at a temperature of 475 °C. The powders were characterized by Raman spectroscopy, UV–VIS, SEM and TEM techniques to determine the crystalline phase, band gap, morphology, and elemental composition, respectively. It was possible to control the anatase/rutile ratio on the nanostructured TiO2 powders from 100% of anatase until a complete transformation to rutile through the variation of the annealing time. The band gap calculated using the Tauc’s model was found in the range of 2.56 to 2.93 eV. However, no direct relationship between the anatase/rutile ratio, and the band gap was found.

This work presents a neural networks approach for finding the effective activation energy and modeling the dissolution rate of hardening precipitates in aluminium alloys using inverse analysis. As way of illustration, a class of multilayer perceptron extended with independent parameters is applied for that purpose to aluminium alloys AA-7449-T79, AA-2198-T8 and AA-6005A-T6.