A Proportional Integral Derivative (PID) controller is commonly used to carry out tasks like position tracking in the industrial robot manipulator controller; however, over time, the PID integral gain generates degradation within the controller, which then produces reduced stability and bandwidth. A proportional derivative (PD) controller has been proposed to deal with the increase in integral gain but is limited if gravity is not compensated for. In practice, the dynamic system non-linearities frequently are unknown or hard to obtain. Adaptive controllers are online schemes that are used to deal with systems that present non-linear and uncertainties dynamics. Adaptive controller use measured data of system trajectory in order to learn and compensate the uncertainties and external disturbances. However, these techniques can adopt more efficient learning methods in order to improve their performance. In this work, a nominal control law is used to achieve a sub-optimal performance, and a scheme based on a cascade neural network is implemented to act as a non-linear compensation whose task is to improve upon the performance of the nominal controller. The main contributions of this work are neural compensation based on a cascade neural networks and the function to update the weights of neural network used. The algorithm is implemented using radial basis function neural networks and a recompense function that leads longer traces for an identification problem. A two-degree-of-freedom robot manipulator is proposed to validate the proposed scheme and compare it with conventional PD control compensation.

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The tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is one of the most important pests of cotton, Gossypium hirsutum L, that has become resistant to a wide range of synthetic insecticides. CrylAc-expressing cotton has proven its effectiveness against this insect since its introduction in North America in 1996. However, the constant exposure of tobacco budworm to this protein toxin may result in the development of resistance to it. To estimate the frequency of alleles that confer resistance to a 1.0 microg of Bacillus thuringiensis Cry1Ac diagnostic concentration in field-collected insects, the second generation (F2) of 1,001 single-pair families from seven geographical regions representing 2,202 alleles from natural populations was screened in 2006 and 2007 without finding major resistant alleles. Neonates of 56 single-pair families were able to develop to second instar on the diagnostic concentration in the initial screen, but only seven of these lines did so again in a second confirmatory screen. Minor resistance alleles to Cry1Ac may be quite common in natural populations of H. virescens. Our estimated resistance allele frequencies (0.0036-0.0263) were not significantly different from a previously published estimate from 1993. There is no evidence that H. virescens populations have become more resistant to Cry1Ac.

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Abstract. Tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), females can copulate multiple times creating the possibility for sperm competition. We used a colony lacking wild pigmentation on the wings (albino-type) for an experiment in which females double mated. Females copulated 2 days apart with two, 2-day-old males, one albino-type and one wild-type, or in the opposite sequence. A third of the females produced offspring from the first mate, and this group was significantly biased toward producing albino-type compared to wild-type progeny. A fourth of the females produced offspring from the second male exclusively and within this group was a significant bias toward wild-type compared to albino-type progeny. Almost half of the females produced offspring sired in equal proportions by both males simultaneously or in alternated paternities throughout all the reproductive life. These results suggest that regardless of the order in which moths mated, wild-type sperm had potential superior competitiveness. Therefore, sperm precedence is not the main driving force behind the paternity allocation mechanism in this strain of tobacco budworm. Resumen.Las hembras del gusano tabacalero, Heliothis virescens (F.) (Lepidoptera: Noctuidae), tienen la capacidad de copular varias veces creando la posibilidad de que haya competencia entre el esperma dentro de ellas. Utilizamos una colonia de este insecto la cual no expresa la pigmentación normal en las alas de las palomillas normales (tipo albino) en un experimento en el cual las hembras tuvieron dos cópulas con dos días de separación, con dos machos de dos días de edad, uno de ellos del tipo albino y el otro del tipo normal así como otros tratamientos en los que la secuencia de machos fue contraria. Una tercera parte de las hembras produjeron progenie del primer macho y dentro de este grupo, hubo una tendencia significativa en producir más progenie del tipo albino que del tipo normal. Una cuarta parte de las hembras produjeron exclusivamente progenie del segundo macho, y dentro de este grupo hubo una tendencia significativa al producir más progenie del tipo normal que del tipo albino. Cerca de la mitad de las hembras produjeron progenie en proporciones similares de los machos normales y albinos simultáneamente, así como en patrones en los que alternaban la paternidad de la 253progenie a lo largo de sus vidas reproductivas. Estos resultados sugieren que sin importar la secuencia en que las palomillas fueron apareadas, el esperma de los machos normales mostró un potencial competitivo mayor y que la precedencia de esperma no es el mecanismo más importante en el momento de distribuir la paternidad en esta colonia de H. virescens.