Chromosome analysis of two species of sugar cane pests of the genus Mahanarva (Homoptera, Cercopidae)

Studies on the cytogenetics of Homoptera are scarce. Some references in the literature have reported a chromosome number for the genus ranging from n=5 to 19 and 2n=10 to 2n=39 chromosomes. The genus Mahanarva includes two species of agricultural importance as pests of sugar cane culture in Brazil. We report here the first data concerning the chromosome number and morphology of the species Mahanarva fimbriolata and M. posticata. The chromosome number observed for the two species was 2n=19 for males and 2n=20 for females. The sex determining mechanism of these species was of the XX/X0 type (for males and females, respectively), with chromosome X being the smallest in the complement.

Molecular characterization and chromosomal localization of two families of satellite DNA in Prochilodus lineatus (Pisces, Prochilodontidae), a species with B chromosomes

Prochilodus lineatus, an abundant species in the Mogi-Guaçu river basin, represents a large part of the region's fishing potential. Karyotypic analyses based on classic cytogenetic techniques have revealed the presence of 54 metasubmetacentric type chromosomes, together with the occurrence of small supernumerary chromosomes with intra and interindividual variations. This paper describes the genomic organization of two families of satellite DNA in the P. lineatus genome. The chromosomal localization these two repetitive DNA families through fluorescence in situ hybridization (FISH) demonstrated that the SATH1 satellite DNA family, composed of approximately 900 bp, was located in the pericentromeric region of a group of chromosomes of the standard complement, as well as on all the B chromosomes. The SATH2 satellite family has a monomeric unit of 441 bp and was located in the pericentromeric regions of some chromosomes of the standard complement, but was absent in the B chromosomes. Double FISH analyses showed that these two families participate jointly in the pericentromeric organization of several chromosomes of this species. The data obtained in this study support the hypothesis that the B chromosomes derive from chromosomes of the standard complement, which are carriers of the SATH1 satellite DNA.

Warm asymmetric matter in the quark-meson coupling model

In this work we study the warm equation of state of asymmetric nuclear matter in the quark-meson coupling model which incorporates explicitly quark degrees of freedom, with quarks coupled to scalar, vector, and isovector mesons. Mechanical and chemical instabilities are discussed as a function of density and isospin asymmetry. The binodal section, essential in the study of the liquid-gas phase transition is also constructed and discussed. The main results for the equation of state are compared with two common parametrizations used in the nonlinear Walecka model and the differences are outlined.

The ant (Hymenoptera: Formicidae) community in two species of the Euphorbiaceae, Alchornea sidifolia and Croton floribundus, in an area of the Atlantic Forest of Brazil

The number of individuals and species richness of ants were investigated in two species of Euphorbiaceae found in three areas of differentiated flora. These areas form part of a fragment of the Atlantic Forest located in the Serra do Itapety, in the state of São Paulo, Brazil. Fifty eight ant species were sampled, belonging to 23 genera and 6 sub-families; 40% of the species are arboreal. The sub-family Myrmicinae was the richest in species, with Pheidole being the most diverse genus and Crematogaster the most commonly-occurring. In the three study areas, no significant differences were found between the number of individuals and the species richness of ants collected on the trunks of Euphorbiaceae. C. floribundus Spreng and A. sidifolia Muell. Arg. are similar with respect to the number of ant species sampled; the number collected being 40 and 47, respectively.

High content of constitutive heterochromatin in two species of Pseudonannolene (Diplopoda)

Due to the fact that a considerable amount of constitutive heterochromatin has been commonly found in millipedes, this paper presents the characterization of the chromosomal complement, through C-banding technique, of two species of millipedes belonging to the genus Pseudonannolene. The species Pseudonannolene tocaiensis shows 2n=20, with five chromosomal pairs almost completely heterochromatic and the remaining pairs with pericentromeric C+ blocks. P. silvestris shows 2n=16, with a large heterochromatic portion in the first two pairs of autosomes, which presented the long arms totally C+.

Quantum gauge boson propagators in the light front

Gauge fields in the light front are traditionally addressed via, the employment of an algebraic condition n·A = 0 in the Lagrangian density, where Aμ is the gauge field (Abelian or non-Abelian) and nμ is the external, light-like, constant vector which defines the gauge proper. However, this condition though necessary is not sufficient to fix the gauge completely; there still remains a residual gauge freedom that must be addressed appropriately. To do this, we need to define the condition (n·A) (∂·A) = 0 with n·A = 0 = ∂·A. The implementation of this condition in the theory gives rise to a gauge boson propagator (in momentum space) leading to conspicuous nonlocal singularities of the type (k·n)-α where α = 1, 2. These singularities must be conveniently treated, and by convenient we mean not only mathemathically well-defined but physically sound and meaningful as well. In calculating such a propagator for one and two noncovariant gauge bosons those singularities demand from the outset the use of a prescription such as the Mandelstam-Leibbrandt (ML) one. We show that the implementation of the ML prescription does not remove certain pathologies associated with zero modes. However we present a causal, singularity-softening prescription and show how to keep causality from being broken without the zero mode nuisance and letting only the propagation of physical degrees of freedom.

Physiological and cellular responses in two populations of the mussel Perna perna collected at different sites from the Coast of São Paulo, Brazil

The physiological conditions of mussels from Ubatuba and Santos and also of organisms transplanted from Ubatuba to Santos were studied by using different techniques. Assays for lysosomal stability were conducted on the haemolymph. Heart rate activity was monitored for 6h. The embryonic development of larvae obtained from the collected mussels was analysed. For all the compared groups of mussels, no significant differences were observed for the cardiac activity monitoring and the embryonic bioassays. The mean Neutral Red (NR) retention time was similar for the animals from Santos and Ubatuba, whereas the organisms transplanted to Santos showed a reduction in the retention time of the dye, indicating damage in the lysosomal membranes. These differences were possibly due to environmental factors, but further investigations are required to confirm this hypothesis.

High content of constitutive heterochromatin in two species of Pseudonannolene (Diplopoda)

Due to the fact that a considerable amount of constitutive heterochromatin has been commonly found in millipedes, this paper presents the characterization of the chromosomal complement, through C-banding technique, of two species of millipedes belonging to the genus Pseudonannolene. The species Pseudonannolene tocaiensis shows 2n=20, with five chromosomal pairs almost completely heterochromatic and the remaining pairs with pericentromeric C+ blocks. P. silvestris shows 2n=16, with a large heterochromatic portion in the first two pairs of autosomes, which presented the long arms totally C+.

Use of carambola (Averrhoa carambola L. 'Fwang Tung') fruit at two stages of maturity for fresh-cut products

Carambola fruit ('Fwang Tung') were picked at two stages of maturity: mature-green (50% yellow) and mature (100% yellow). Fruit were washed with water, dipped in NaOCl solution (200 mg.L-1 for 5 minutes), and stored over night at 10°C. Fruit were sliced manually in to pieces of approximately 1 cm thickness. Slices were rinsed with NaOCl solution at 20 mg.L-1, drained for 3 minutes, and packaged in polyethylene tereftalate (PET) trays provided with a fit cover (Neoform® N94). Packages were stored at 6.5°C and 85% RH for 9 days, and samples taken every 3 days for physical, chemical and biochemical analysis, respiration, and internal atmosphere composition. Immediately after cutting, slices at both stages of maturity showed a wounding response with a 5-fold increase in respiration rate. Polygalacturonase (PG) and polyphenol oxidase (PPO) activity did not differ between stages of maturity. Despite the less mature stage being less preferred at the sensory evaluation owing to its greenish peel, the best stage of maturity for carambola fresh-cut production was mature-green, due to a higher resistance to cutting, and presenting a better colour and appearance maintenance for up to 9 days.

Occurrence of Actinobacillus actinomycetemcomitans in patients with chronic periodontitis, aggressive periodontitis, healthy subjects and children with gingivitis in two cities of the state of São Paulo, Brazil

The aim of this study was to determine the frequency of isolation of Actinobacillus actinomycetemcomitans (Aa) in 100 patients with chronic periodontitis, 14 patients with aggressive periodontitis, 142 pre-school children with gingivitis and 134 periodontally healthy subjects. Samples of subgingival plaque were taken using sterilized paper points introduced into periodontal pockets or gingival crevice for 60 seconds and inoculated on TSBV agar, which was incubated under anaerobiosis at 37°C, for 4 days. Microbial identification was performed through biochemical methods and morphocellular and morphocolonial analysis. Aa was detected in 40.3% of healthy subjects, 68% of patients with chronic periodontitis, 92.86% of patients with aggressive periodontitis and 40.14% of children with gingivitis. The rate of recovery of Aa in the tested human groups proved to be higher than previously reported and in agreement with participation of this facultative anaerobe as a member of native microbiota of the periodontium and its relation with aggressive and chronic periodontitis in Brazil.

Microhardness assessment of different commercial brands of resin composites with different degrees of translucence

Owing to improvements in its mechanical properties and to the availability of shade and translucence resources, resin composite has become one of the most widely used restorative materials in present day Dentistry. The aim of this study was to assess the relation between the surface hardness of seven different commercial brands of resin composites (Charisma, Fill Magic, Master Fill, Natural Look, Opallis, Tetric Ceram, and Z250) and the different degrees of translucence (translucid, enamel and dentin). Vickers microhardness testing revealed significant differences among the groups. Z250 was the commercial brand that showed the best performance in the hardness test. When comparing the three groups assessed within the same brand, only Master Fill and Fill Magic presented statistically significant differences among all of the different translucencies. Natural Look was the only one that showed no significant difference among any of the three groups. Charisma, Opallis, Tetric Ceram and Z250 showed significant differences among some of the tested groups. Based on the results found in this study, it was not possible to establish a relation between translucence and the microhardness of the resin composites assessed. Depending on the material assessed, however, translucence variation did affect the microhardness values of the resin composites.

Two decades of adjustment and agricultural development in Latin America and the Caribbean

Includes bibliography

Effectiveness of three solvents and two associations of solvents on gutta-percha and Resilon

This study evaluated the effectiveness of 3 solvents (Citrol orange oil, Eucalyptol and Tetrachloroethylene) and 2 associations of solvents (Citrol orange oil+Tetrachloroethylene and Eucalyptol+Tetrachloroethylene) on 3 types of gutta-percha (conventional, thermoplastic and EndoREZ) and Resilon. Ten discs (10 mm diameter x 1 mm thick) from each material were prepared using standard metallic molds. Each specimen was weighed to determinate its initial mass. The specimens were immersed in the solvents for 10 min, followed by immersion in distilled water for 20 min, and were then reweighed to obtain the final mass. The mean weight loss determined the solvent capacity. Data were analyzed by ANOVA and Tukey's test at 5% significance level. Tetrachloroethylene was the most effective on conventional gutta-percha (p<0.05). Tetrachloroethylene was also the most effective on thermoplastic gutta-percha, but it was not significantly different (p>0.05) from Eucalyptol+Tetrachloroethylene, Citrol+Tetrachloroethylene, and Citrol. All solvents and associations presented little effectiveness on Resilon. The association Eucalyptol+Tetrachloroethylene was the most effective on EndoREZ, but it did not differ significantly (p>0.05) from Citrol+Tetrachloroethylene and Tetrachloroethylene. All evaluated substances presented solvent action. Tetrachloroethylene improved the effectiveness of both Citrol and Eucalyptol.

Simulation of dynamic pinion course using Runge-Kutta's method and impact modeling

Once defined the relationship between the Starter Motor components and their functions, it is possible to develop a mathematical model capable to predict the Starter behavior during operation. One important aspect is the engagement system behavior. The development of a mathematical tool capable of predicting it is a valuable step in order to reduce the design time, cost and engineering efforts. A mathematical model, represented by differential equations, can be developed using physics laws, evaluating force balance and energy flow through the systems degrees of freedom. Another important physical aspect to be considered in this modeling is the impact conditions (particularly on the pinion and ring-gear contact). This work is a report of those equations application on available mathematical software and the resolution of those equations by Runge-Kutta's numerical integration method, in order to build an accessible engineering tool. Copyright © 2011 SAE International.

Two decades of adjustment and agricultural development in Latin America and the Caribbean

Includes bibliography