Description of Dichelacera (Dichelacera) walteri n. sp. (Diptera: Tabanidae) with a Key to Related Species in the Subgenus Dichelacera Macquart.

Dichelacera (Dichelacera) walteri Guimarães, Gorayeb & Rodrigues-Guimarães n. sp. is described from female specimens collected in Marambaia Island, located in Mangaratiba County, state of Rio de Janeiro, Brazil. The characterization of the species was based in the following characters: a medium-sized species, more sclerotized than others in the subgenus Dichelacera Macquart, the second segment of palp with dark setae and longer than the third antennal segment, a brown scutum with pruinescence on the anterior half and posterior edges with white tonality, yellow dorsum of abdomen with the last three segments brown, white-yellowish venter with yellow setae, narrow frons with dark brown callus, extending just beyond a ridge in the middle of the frons, vertex with ocelli, hyaline wings with three large black bands, and tricolored legs.

Annihilation dynamics of stringlike topological defects in a nematic lyotropic liquid crystal.

Topological defects can appear whenever there is some type of ordering. Its ubiquity in nature has been the subject of several studies, from early Universe to condensed matter. In this work, we investigated the annihilation dynamics of defects and antidefects in a lyotropic nematic liquid crystal (ternary mixture of potassium laurate, decanol and deionized-destillated water) using the polarized optical light microscopy technique. We analyzed Schlieren textures with topological defects produced due to a symmetry breaking in the transition of the isotropic to nematic calamitic phase after a temperature quench. As result, we obtained for the distance D between two annihilating defects (defect-antidefect pair), as a function of time t remaining for the annihilation, the scaling law D âˆ t(α), with α = 0.390 and standard deviation σ = 0.085. Our findings go in the direction to extend experimental results related to dynamics of defects in liquid crystals since only thermotropic and polymerics ones had been investigated. In addition, our results are in good quantitative agreement with previous investigations on the subject.

Antipersistent behavior of defects in a lyotropic liquid crystal during annihilation.

We report on the dynamical behavior of defects of strength s=±1/2 in a lyotropic liquid crystal during the annihilation process. By following their positions using time-resolved polarizing microscopy technique, we present statistically significant evidence that the relative velocity between defect pairs is Gaussian distributed, antipersistent, and long-range correlated. We further show that simulations of the Lebwohl-Lasher model reproduce quite well our experimental findings.

[Thoracic radiologic aspects in paracoccidioidomycosis]. / Aspectos radiológicos torácicos na paracoccidioidomicose.

In this paper the authors analyse 159 radiographs from paracoccidioidomycosis patients seen at the Evandro Chagas Hospital/Fiocruz in the period between January 1960 to December 1988. Twenty four cases (15.09%) of association with tuberculosis were observed; one with pneumoconiosis; one with aspergillosis, and two with carcinoma. Twenty cases were excluded from the radiologic analysis: in 8 of these the diagnosis of tuberculosis occurred concomitantly, and in 12 patients, lung fibrosis due to previous treatment for tuberculosis or paracoccidioidomycosis was present in the 139 remaining cases, the radiographic abnormalities encountered were grouped according to the predominance of lesions at the various lung sites, if alveolar or interstitial, according to Magalhães' (1982) classification modified by the authors: infiltrate 55 cases (39.6%); mist 28 (20.1%); pneumonic 23 (16.6%); nodular 16 (11.5%); micronodular 10 (7.2%), and fibrotic 7 (5.0%). In 113 cases it was possible to follow the regression of the pulmonary process radiologically. In 85 (75.2%) patients, regression took place within 6 months; in 17 (15.0%) cases between 7 and 12 months; in 4 (3.5%) between 13 and 24 months, and in 7 (6.1%) cases no changes in the radiographic pattern were noted.