Showing papers by "Federal University of Rio de Janeiro published in 1978"

Observer design for linear systems with unknown inputs

Abstract: Results from the geometric theory of linear systems are utilized to present a constructive solution to the problem of designing a Luenberger observer to evaluate a given set of linear functions of the state of a linear system subject to unknown or disturbance inputs

Resource partitioning in passion vine butterflies.

Abstract: The use of phytophagous insect communities as model systems to elucidate ecoevolutionary processes, although encountering considerable success in some areas (Southwood, 1960, 1961; Opler, 1974; Strong, 1974a,b), has not been actively extended to include competitive phenomena. The partitioning of food resources has been well documented in many animal groups, especially vertebrate predators (Schoener, 1974); however, the few studies made to date have not presented convincing evidence that such patterns are typical for any group of invertebrate herbivores. Several possible cases of competition related resource partitioning between pairs of lepidopteran species have been reported by Gilbert and Singer (1976) from an extensive examination of the lepidopteran literature, and Shapiro and Carde (1970) suggested that host plant and habitat separation among three species of satyrine butterflies may be explicable in terms of competition induced ecological shifts. On a larger scale Owen (1972) noted that the patterns of host plant use in West African acraeine butterflies are consistent with resource partitioning. On the other hand, very few studies have specifically examined the dynamics of resource use as related to competition. Colwell (1973) has presented a convincing picture of the ecological dynamics accounting for host plant separation of two potentially competing nectivorous mites. However, the only study to date specifically designed to identify partitioning within an insect herbivore guild failed to reveal clearcut patterns among temperate stem-borers (Rathcke, 1976). Moreover, theoretical arguments have been put forward to suggest that unambiguous patterns of resource partitioning are not generally to be expected in invertebrate herbivores, and May (1973:166) goes even farther in stating that ". many insect communities, and many plant communities, have complex multidimensional niche structure involving, inter alia, a variety of chemical dimensions. In addition predation and other interactions beyond simple competition are pervasive in these invertebrate and plant communities. Such situations are best avoided for the time being." I present here evidence that at least one group of insect herbivores corresponds in many details to predictions derivable from competition and foraging theory and discuss some of the more important details and extensions of these predictions.

Solar dosimetry with repair deficient bacterial spores: action spectra, photoproduct measurements and a comparison with other biological systems

Abstract: — Populations of radiation sensitive spores (Bacillus subtilis UVSSP), vegetative bacteria (E. coli K12-AB2480) and bacteriophage (E. coli phage T4vx) have been considered as possible biological dosimeters to integrate DNA-absorbed solar energy incident on the Earth's surface. Irradiation of spores of B. subtilis UVSSP with monochromatic far- and near-UV radiation and solar radiation have indicated that these radiations have a similar efficiency in inducing spore photoproducts per lethal event. Action spectra for lethality taken with the three radiation sensitive biological systems show a similar pattern in each case with a broad shoulder in the 334–365 nm wavelength region. This finding indicates a relatively high susceptibility of the DNA to chemical alteration in this wavelength range. Although less sensitive to sunlight than the other biological systems tested, the B. subtilis UVSSP spore mutant has the advantage of temperature independence of inactivation, stability between irradiation and assay and a simple, reproducible irradiation and assay procedure. Field measurements have supported the utility of this mutant as a sunlight dosimeter.

Radiation Synergism and Antagonism

Abstract: The above statement probably approaches the simplest definition of the wide variety of phenomena denoted as synergisms and antagonisms. A more careful description and qualification of these terms will be given in Sections 1.2 and 2.1. An enormous range of such interactions has been reported between chemicals, between chemicals and radiation, and between radiations at all levels of biological organization. Despite rising concern for the possible detrimental effects of industrial by-products (chemicals, heat, and even radiation) cast into the environment, relatively little attention has been given to the enormous potential that these agents may have for interacting with each other and with natural environmental agents (including chemicals and sunlight) to cause profound biological changes. Thus, interaction studies should form a basic part of environmental control programs. Until now experiments have been principally directed either toward medical and industrial applications, or to more fundamental problems of cellular function.

Generation of Superoxide Anions and Hydrogen Peroxide from β-Lapachone in Bacteria

Abstract: beta-Lapachone markedly increased the generation of superoxide anions and hydrogen peroxide by subcellular membranes of Bacillus subtilis and Bacillus stearothermophilus. Peroxide generation by beta-lapachone was parallel to the inhibition of growth in both microorganisms.

Some Challenges Offered to Analysis by Rational Thermomechanics: Three Lectures for the International Symposium on Continuum Mechanics and Partial Differential equations

Abstract: Publisher Summary This chapter discusses some challenges that are offered to analysis by rational thermomechanics. The chapter discusses about Coleman's thermodynamics of materials with fading memory, which has replaced a century of vague claims by a concrete mathematical structure that serves as a model of what thermodynamics can and should do. It also refers to Joseph's development of a method of domain perturbation for determining the free surfaces of simple fluids. His results enable to predict a wide class of motions of nonlinear fluids with a degree of explicitness and accuracy that was earlier not possible. The chapter discusses unsolved problems of rational thermomechanics, solution of which calls in equal measure upon rational thermomechanics and analysis. A detailed discussion on elasticity, thermodynamics, and kinetic theory of gases is presented in the chapter.

The projection of the opossum's visual field on the cerebral cortex†

Abstract: The visual cortex of the opossum was studied by means of evoked potential and multi-unit recordings, and a map of the visual field in VI was constructed: Evoked responses were observed in regions extending beyond the boundaries of striate cortex. Different patterns of response were obtained depending on the cortical region undergoing exploration: in a posteromedial region, coincident with striate area, complex waveforms were obtained, contrasting with the simpler forms observed in a region localized anterolaterally. VI, which corresponds to cytoarchitectonic area 17, has a topography of projections similar to that found in other mammals: the upper visual field represented posteriorly, the temporal field represented medially, the lower field represented anteriorly and the nasal part laterally. A large proportion of VI is devoted to the region of binocular representation, which covers approximately100° at the level of the horizontal meridian. The cortical representation of the vertical meridian extends to approximately 60°above and below the center of gaze, suggesting that the cortical representation of the visual field is more restricted than the visual field available to the contralateral hemiretina. Our results suggest that the extreme periphery of the field is not represented in VI. In its lateral border the projection does not end at the vertical meridian, it extends 5° into the ipsilateral hemififield of vision, so that approximately 10° of visual field is represented in both hemispheres. There is a reversal of representation along the lateral border of VI, in a region which coincides with the cytoarchitectonic boundaries of striate and peristriate areas, suggesting the existence of at least a second representation of the visual field in the neocortex of the opossum, corresponding to VII of other animals. The magnification factor in VI varied from 7°/mm observed at the cortical representation of the center of gaze, to 30°/mm at the extreme periphery of the field, along the horizontal meridian. A comparable decrease was also observed along the vertical meridian, towards the upper and lower limits of the visual field.

An approach to the implementation of digital filters using microprocessors

Abstract: The design of digital filters using microprocessors is discussed along with simple solutions to improve the speed and memory requirements of such systems.

Empirical comparisons of some tests of separate families of hypotheses

Abstract: This paper is devoted to a comparison of the asymptotic tests of separate families of hypotheses proposed byCox [1961, 1962] and byAtkinson [1970]. The adequacy of the asymptotic results for finite samples is investigated and some conclusions reached. An examination of the terms which differentiate the two procedures is made. Empirical simulated results are discussed for cases involving the exponential, the lognormal and the Weibull distributions.

Ultrastructural alterations and peroxide formation induced by naphthoquinones in different stages of Trypanosoma cruzi.

Abstract: Addition of β-lapachone, ano-naphthoquinone with bactericidal, cytotoxic, and trypanocidal activities, toTrypanosoma cruzi epimastigote and amastigote stages induced the release of O2− and H2O2 from the whole cells into the suspending medium. In the presence of reduced nicotinamide adenine dinucleotide as reductant β-lapachone was also able to stimulate O2− and H2O2 production by homogenates of these stages. Electron micrographs showed that in β-lapachone-treated amastigotes and trypomastigotes, the chromatin is arranged in patches, clearly differing from the normal pattern of chromatin distribution.

Ultrastructural localization of basic proteins on the conoid, rhoptries and micronemes of Toxoplasma gondii.

Abstract: The ethanolic phosphotungstic acid (E-PTA) technique was used to locate basic proteins in trophozoites ofToxoplasma gondii, obtained from the peritoneal exudate of infected mice. The reaction was observed mainly on the conoid, rhoptries, and micronemes of both extracellular and intracellular parasites. The strongest reaction was observed on rhoptries. Nuclei and ribosomes from parasites and host cells also reacted. The role of basic proteins on rhoptries and micronemes is discussed with a view on host-cell penetration by the parasite.

Mutagenic interaction between near-(365 nm) and far-(254 nm) ultraviolet radition in repair-proficient and excision-deficient strains of Escherichia coli

Abstract: The mutational interaction between radiation at 365 and 254 nm was studied in various strains of E. coli by a mutant assay based on reversion to amino-acid independence in full nutrient conditions. In the two repair-proficients strains (K12 AB 1157 and B/r), pre-treatment with radiation at 365 nm strongly suppressed the induction of mutations by far-UV, a phenomenon accompanied by a strong positive lethal interaction. The frequency of mutations induced by far-UV progressively declined with increasing dose of near-UV. Far-UV-induced mutagenesis to T5 resistance was almost unaltered by pre-treatment with near-UV. In AB 1886 uvrA there was no lethal interaction between the two wavelengths but the mutagenic interaction was synergistic. This synergism was maximal at a 365-nm dose of 8 × 105 J m−2. It is proposed that in the wild-type strain, cells containing potentially mutagenic lesions are selectively eliminated from the population because of abortive excision of an error-prone repair-inducing signal. In excisionless strains, 365-nm radition may be less damaging to the erro-prone than to the erro-free post-replication repair system. Alternatively, mutation may be enhanced because of the occurrence of error-prone repair of 365-nm lesions by a system that is not induced in the absence of 254-nm radiation.

A Nonlinear Load-Frequency Control Design

Abstract: A load frequency control for a two-area interconnected system is designed taking into account the nonlinearity and stochasticy of the load and using an optimal linear strategy aided by stability analysis. An observer is proposed for its implementation. A coordinating control for the two area system based on acceleration feedback is suggested.

Tests and efficiencies of separate regression models

Abstract: SUMMARY The results of Cox (1961, 1962) on tests of separate families of hypotheses are used to develop tests for some log linear regression models. The consequences of using one model when another is true are studied. The probability limits and asymptotic efficiencies of the estimators of the regression coefficients when using a false model in relation to the true model are investigated.

Screening and Structure-Activity Relationships of Synthetic Juvenile Hormone Analogues for Panstrongylus megistus, a Primary Vector of Chagas’ Disease in Brazil

Abstract: As part of the search for new agents and methods for the control of triatomine bugs: 40 compounds were bioassayed for juvenile hormone activity on Panstrongylus megistus (Burmeister), one of the most important transmitters of Chagas’ disease in Brazil. Compounds of several different structural classes were tested, and high levels of activity were observed for some aromatic terpenoid ethers and amines. The most active compound was N -(5-chloro-2-methylphenyl)-3,7-dimethyl-2,6-octadienylamine; a single topical application of 0.1 μg/insect resulted in a high degree of Juvenilization. From a comparison of the structures of the active compounds, the presence of an electro-negative group, such as alkoxy or chlorine, meta to the terpenoid side chain, is a prerequisite for high juvenile hormone activity on this insect.

Auditoria em enfermagem

Abstract: INTRODUCAO A auditoria em enfermagem e o as­sunto empolgante do momento nas ati­vidades administrativas de enfermagem, motivo pelo qual nos conduziu a reali­zar seu estudo identificando seus obje­tivos, metodologia e validade. Atualmente, na transicao acelerada da enfermagem para um assentamento cientifico, urge adquirir solidez que a ciencia exige em seus conceitos e acao. A revisao bibliografica mostra a pra­ticidade de alguns tipos de auditoria, senao em nosso pais, pelo menos nos Estados Unidos. Em nosso meio profissional o desper­tar a auditoria ainda e il!�ipiente, ne­cessitando consolidar seus fundamentos, estudos adaptativos que se moldem a realidade brasileira. Tivemos a oportunidade de realizar contatos pessoais com profissionais da area, objetivando apreciar a sua aplica­cao em Hospitais Municipais e Previ­denciarios do Rio de Janeiro. Constatamos a ausencia na acao au­ditoria!. Pareceu-nos que ha motivacao bas­tante