ALTERATIONS IN THE OMMATIDIA OF THE COMPOUND EYES OF APIS-MELLIFERA EYE-COLOR MUTANT WORKERS .3.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

ULTRASTRUCTURE OF THE MANDIBULAR GLANDS OF PACHYCONDYLA-STRIATA ANTS (HYMENOPTERA, PONERINAE) .1. WORKERS

The mandibular glands of Pachycondyla striata workers consists of a proximal reservoir and secretory portion. The secretion is transported from the cytoplasm of the secretory cells to reservoir through individual canaliculi which is subdivided into two portions : an intracytoplasmatic and extracellular one. The reservoir consists of an epithelium made up of thin cells has a thick cuticle. The secretory cells showed a large amount of structures forming the citoskeleton always associated with myelin figures.

Water sorption enthalpy-entropy compensation based on isotherms of plum skin and pulp

The net isosteric heat and entropy of water sorption were calculated for plum, based on sorption isotherms obtained by the static gravimetric method at different temperatures (20 to 70 degrees C). The Guggenheim-Anderson-deBoer model was applied to the experimental data giving a good agreement between experimental and calculated values. The net isosteric heat of water sorption, estimated by applying Claussius-Clapeyron equation to sorption isotherms, was found to be different for plum skin and pulp, mainly at low moisture contents, and could be well adjusted by an empirical exponential relationship. Plots of enthalpy in contrast to entropy provided the isokinetic temperatures for skin and pulp, indicating an enthalpy-controlled sorption process. Thermodynamic data on water sorption for plums are not found in literature, as opposed to prunes for which the data are abundant.

Methodology for load compensation in four-wire electrical power systems based on instantaneous sampling

This work describes a methodology for power factor control and correction of the unbalanced currents in four-wire electric circuits. The methodology is based on the insertion of two compensation networks, one wye-grounded neutral and other in delta, in parallel to the load. The mathematical development has been proposed in previous work [3]. In this paper, however, the determination of the compensation susceptances is based on the instantaneous values of load currents. The results are obtained using the MatLab-Simulink enviroment

Sleep-wake patterns of student workers and non-workers

Adolescents usually exhibit late sleep phase and irregular sleep patterns. As a result, they do not get enough sleep and report daytime sleepiness. This condition could be aggravated in working students who have a more limited time for sleep. In this survey, we investigated the impact of evening classes and employment on the sleep patterns of adolescents. We compared female (n = 17) and male (n = 14) non-worker students to female (n = 28) and male (n = 20) worker students who attended the same high school. The volunteers (aged 17.4 years +/- 11 months) answered a sleep log during a 16-day period. Worker students slept and woke up earlier, had a shorter nocturnal sleep length and a shorter daily (nocturnal plus diurnal) sleep length compared to non-working pupils. The four groups of students delayed sleep onset time on weekends, but only worker students delayed wake-up time on Sundays. The wake-up time was similar among groups on Sundays. While student workers tended to increase the sleep length in the weekends, non-working students increased it on Mondays and/or Tuesdays. The results showed that sleep schedules and sleep length were different according to the work status. Going to bed later on Saturday by the four groups of students suggests the influence of social activities, while a later wake-up time on Sundays could result from a shorter sleep length on workdays.

HERITABILITY OF THE NUMBER OF OVARIOLES IN HONEY-BEE WORKERS (APIS-MELLIFERA L) (HYM, APIDAE)

Narrow and broad sense heritabilities (h(2)) of the number of ovarioles in Apis mellifera L. workers were estimated using two distinct data sets, based on groups of half (queens inseminated by several drones) and super-sisters (single drone insemination). The values found are in the usual range for economically important characters (0.25-0.38).

Morphological caste differences and non-sterility of workers in Brachygastra augusti (Hymenoptera, Vespidae, Epiponini), a neotropical swarm-founding wasp

Morphological caste differences and ovary conditions were analyzed in four colonies of Brachygastra augusti collected in different stages of the colony cycle. Differences between castes are distinct suggesting pre-imaginal determination. Many intermediates (non-inseminated ovary-developed females) were found. Because these intermediate females were morphologically similar to workers, it is suggested that they are young ovary-developed workers. Because there is a more evident overlap between queens and workers in the colony in pre-emergence of workers stage, and in three colonies in latter stages, especially in worker-production colonies, it is suggested that smaller queens are probably less viable than larger queens as observed in previously studied epiponines.

Ant Group Effects on the Insecticide and Dye Flow Among Atta sexdens rubropilosa (Hymenoptera: Formicidae) Workers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Possible shunt compensation strategies based on Conservative Power Theory

Considering the Conservative Power Theory (CPT), this paper proposes some novel compensation strategies for shunt passive or active devices. The CPT current decompositions result in several current terms (associated with specific physical phenomena), which were used for the definition of different selective current compensators, in terms of minimizing particular disturbing effects. Simulation results have been demonstrated in order to validate the possibilities and performance of the proposed strategies for single and three-phase four wired circuits.