Chromosome comparison between populations of the collared peccary, Tayassu tajacu, raised in captivity

The collared peccary (Tayassu tajacu) is widely distributed over the American continent, being found from the south of the USA to the north of Argentina. In Brazil, it is spread all over the country, being one of the potential species to be raised in captivity. Therefore, the cytogenetic techniques could be a potential tool for reproductive monitoring of animals raised in captivity, mainly when destined for commercial purposes. This study had the objective of determining the chromosome number of two populations raised in captivity and characterizing them by GTG banding. For this purpose, an analysis was made of mitotic metaphases obtained from lymphocyte cultures made from blood samples of 11 animals, six of which from the Northeast and five from the North of Brazil. The results of this analysis showed the same karyotype pattern for the species (2n=30 chromosomes and NF=48), besides corresponding to the South American pattern of the species, i.e., without a translocation between autosomes 1 and 8, chromosome X acrocentric, and no differences were found between the two populations studied. However, chromosomal polymorphisms were observed compared to data from the literature on populations from North and South America.     

Genotoxic effect of Physalis angulata L. (Solanaceae) extract on human lymphocytes treated in vitro

Physalis angulata L (Solanaceae) is a medicinal plant from North of Brazil, whose different extracts and infusions are commonly used in the popular medicine for the treatment of malaria, asthma, hepatitis, dermatitis and rheumatism. However, the genotoxic effects of P. angulata on human cells is not well known. The main purpose of the present study was to evaluate the in vitro genotoxic effects of aqueous extract of P. angulata using the comet assay and the micronucleus assay in human lymphocytes provided from 6 healthy donors. Treatments with P. angulata extracts were performed in vitro in order to access the extent of DNA damage. The comet assay has shown that treatments with P. angulata at 0.5, 1.0, 2.0, 3.0 and 6.0 microg/mL in culture medium were genotoxic. Lymphocytes treated with P. angulata at the concentrations of 3.0 and 6.0 microg/mL in culture medium showed a statistically significant increase in the frequency of micronucleus (p<0.05), however, the cytokinesis blocked proliferation index (CBPI) was not decreased after P. angulata treatment. In conclusion, the present work demonstrated the genotoxic effects of P. angulata extract on human lymphocytes in vitro.     

Error Estimates for an LDG Method Applied to Signorini Type Problems

In this paper we propose and analyze a Local Discontinuous Galerkin method for an elliptic variational inequality of the first kind that corresponds to a Poisson equation with Signorini type condition on part of the boundary. The method uses piecewise polynomials of degree one for the field variable and of degree zero or one for the approximation of its gradient. We show optimal convergence for the method and illustrate it with some numerical experiments.     

An A Posteriori Error Estimate for the Local Discontinuous Galerkin Method Applied to Linear and Nonlinear Diffusion Problems

In this paper we present a new residual-based reliable a posteriori error estimator for the local discontinuous Galerkin approximations of linear and nonlinear diffusion problems in polygonal regions of R ². Our analysis, which applies to convex and nonconvex domains, is based on Helmholtz decompositions of the error and a suitable auxiliary polynomial function interpolating the Dirichlet datum. Several examples confirming the reliability of the estimator and providing numerical evidences for its efficiency are given. Furthermore, the associated adaptive method, which considers meshes with and without hanging nodes, is shown to be much more efficient than a uniform refinement to compute the discrete solutions. In particular, the experiments illustrate the ability of the adaptive algorithm to localize the singularities of each problem.Mathematics Subject Classifications (1991). 65N30This revised version was published online in July 2005 with corrected volume and issue numbers.     

Quantitative oxide charge determination by photocurrent analysis

A new method is presented for the quantitative determination of insulator charges Q_Is from photo induced diffusion currents. Q_Is is determined by analyzing the interface recombination of charge carriers in illuminated electrolyte/insulator/semiconductor structures. Measured characteristics are explained theoretically and an evaluation procedure is developed for the determination of Q_Is which is based on the comparison of the simulated with the experimental data. Q_Is values obtained from the proposed method are compared with those from capacitance voltage measurements. A very good agreement can be observed between the results of both methods.     

Issues on the chalcopyrite/defect-chalcopyrite junction model for high-efficiency Cu(In,Ga)Se2 solar cells

Considering the chalcopyrite/defect-chalcopyrite junction model for Cu(In_1−xGa_x)Se₂-based devices and our previously reported findings for the Cu(In_1−xGa_x)₃Se₅ defect chalcopyrites, we have postulated that uniform high-Ga-content photovoltaic structures (with x > 0.35) do not yield acceptable device performance due to the electrical and structural differences between both types of materials (chalcopyrite and defect-chalcopyrite).In this contribution, the structural properties of the surface region of Ga containing absorber materials have been studied by grazing incidence X-ray diffraction. We find that there are significant differences between surface and bulk. A structural model is proposed for the growth of the chalcopyrite/defect-chalcopyrite junction relative to its Ga content. And we demonstrate that closely lattice matched high-Ga-content structures (x > 0.35) can produce solar cells withv acceptable performances. The high-voltage and low-current electrical outputs from high Ga structures are very desirable in module fabrication because overall resistive losses can be substantially reduced.     

Familial deletions of chromosome 22q11: the Leuven experience

Renal medullary carcinoma is a recently described tumor that occurs exclusively in patients with sickle cell trait. Although extremely rare, the distinctive demographic, clinical, and radiologic findings should suggest the diagnosis of this aggressive neoplasm.     

Zur Elektrodenkinetik von Reinst – Eisen im Phosphatelektrolyten bei Feststoffeinschlag (Simulation von Erosionskorrosion)

Electrode kinetics of high purity iron in phosphate electrolytes under solid particle impact (Simulation of erosion corrosion) Erosion-corrosion of high purity iron was simulated by means of a vibration cell in a neutral phosphate electrolyte. The investigations were carried out to explain the initiation processes of this type of corrosion. The results confirm the general conception of the central role of reaction layer destruction in erosion-corrosion processes. Under these conditions a qualitative change in reaction layer formation occur. By solid impact the layers are destroyed locally and so conditions of pit nucleation exist. The destruction of the layers depends on the action of shear forces resulting from tensile or compressive strains.     

Studies on biotechnical ovulation synchronization in young cows. 1. Ovulation periods, ovarian findings and fertilization results after use of Metallibur, 750 IE PMS and 250 or 500 IE HCG

The following treatment was applied to 50 mature young sows in two experiments (22 and 28 animals) throughout 20 days: Turisynchron-Pr?mix (Turi.), 5 g/animal, and 750 IU PMS (Prolosan serum) 28 hours after Turi. In the first experiment. 250 IU HCG (Gonabion) were additionally injected to each of twelve animals 100 hours after Turi., while in the second experiment each of ten animals recieved 500 IU HCG 103 hours after Turi. The remaining animals of the two groups were used as controls. Inseminations took place 101 and 104 hours (fourth day) after Turi. in the first experiment and 125, 149, as well as 173 hours (fifth, sixth, and seventh days) after Turi. in the second. Onset of ovulation was brought forward to the sixth day after Turi. in response to 500 IU HCG by laparotomy performed in the mornings and evenings of the fourth through seventh days. Most of the controls and test animals with 250 IU HCG ovulated on the sixth or seventh day after Turi. Ovulation was stimulated by both HCG dosages, in comparison to the controls, which was established by slaughtering the animals between the seventh and twelfth days after Turi. The percentage of ovulations was higher among the test animals and that of ovarian cysts lower. Fertilisation of the second group was clearly better than that in the first where insemination had taken place two days prior to ovulation, that is too early. The latter results were secured by tubal douche and ovocyte tests.