Viabilidade da aplicação do teste tuberculínico com o dermo-jet

Foram estudadas as reações de hipersensibilidade tuberculínica induzidas por aplicações simultâneas, em adultos jovens, de tuberculina (PPD. RT-23, 2UT), com agulha e seringa e com o dermo-jet. Foram encontrados 61,3% de reatores nas aplicações com agulha e seringa para 40,0% de reatores nas aplicações com o dermo-jet. Os resultados não são considerados favoráveis ao uso do injetor a jato na prática corrente de aplicação do teste tuberculínico.

Reações locais e níveis de antitoxina circulante decorrentes de administração do toxóide tetânico: estudo comparativo entre Ped-o-Jet e seringa hipodérmica

Com o objetivo de comparar reações locais e conversão sorológica apresentadas por adultos que receberam o toxóide tetânico através de Ped-o-Jet (via subcutânea) ou de seringa hipodérmica (via intramuscular), o toxóide foi administrado a 472 recrutas do Exército. Em observações realizadas 4 e 24 horas após a vacinação verificou-se que as reações locais dos indivíduos vacinados com Ped-o-Jet eram significativamente mais freqüentes e mais intensas do que aquelas dos vacinados com seringa hipodérmica, não tendo ocorrido, entretanto, reações graves. A conversão sorológica dos não imunes vacinados com Ped-o-Jet ocorreu numa freqüência maior do que nos indivíduos vacinados com seringa hipodérmica. Conclui-se portanto, que o Ped-o-Jet pode ser utilizado em campanhas de vacinação em massa contra o tétano, embora a via de administração preferencial, até o momento, seja a intramuscular.

BEYOND THE “LEAST LIMITING WATER RANGE”: RETHINKING SOIL PHYSICS RESEARCH IN BRAZIL

As opposed to objective definitions in soil physics, the subjective term “soil physical quality” is increasingly found in publications in the soil physics area. A supposed indicator of soil physical quality that has been the focus of attention, especially in the Brazilian literature, is the Least Limiting Water Range (RLL), translated in Portuguese as "Intervalo Hídrico Ótimo" or IHO. In this paper the four limiting water contents that define RLLare discussed in the light of objectively determinable soil physical properties, pointing to inconsistencies in the RLLdefinition and calculation. It also discusses the interpretation of RLL as an indicator of crop productivity or soil physical quality, showing its inability to consider common phenological and pedological boundary conditions. It is shown that so-called “critical densities” found by the RLL through a commonly applied calculation method are questionable. Considering the availability of robust models for agronomy, ecology, hydrology, meteorology and other related areas, the attractiveness of RLL as an indicator to Brazilian soil physicists is not related to its (never proven) effectiveness, but rather to the simplicity with which it is dealt. Determining the respective limiting contents in a simplified manner, relegating the study or concern on the actual functioning of the system to a lower priority, goes against scientific construction and systemic understanding. This study suggests a realignment of the research in soil physics in Brazil with scientific precepts, towards mechanistic soil physics, to replace the currently predominant search for empirical correlations below the state of the art of soil physics.

Experimental Method to Determine Some Physical Properties in Physics Classes

ABSTRACT Particle density, gravimetric and volumetric water contents and porosity are important basic concepts to characterize porous systems such as soils. This paper presents a proposal of an experimental method to measure these physical properties, applicable in experimental physics classes, in porous media samples consisting of spheres with the same diameter (monodisperse medium) and with different diameters (polydisperse medium). Soil samples are not used given the difficulty of working with this porous medium in laboratories dedicated to teaching basic experimental physics. The paper describes the method to be followed and results of two case studies, one in monodisperse medium and the other in polydisperse medium. The particle density results were very close to theoretical values for lead spheres, whose relative deviation (RD) was -2.9 % and +0.1 % RD for the iron spheres. The RD of porosity was also low: -3.6 % for lead spheres and -1.2 % for iron spheres, in the comparison of procedures – using particle and porous medium densities and saturated volumetric water content – and monodisperse and polydisperse media.

An experimental investigation of the effects of nozzle ellipticity on the flow structure of co-flow jet diffusion flames

The flow structure of cold and ignited jets issuing into a co-flowing air stream was experimentally studied using a laser Doppler velocimeter. Methane was employed as the jet fluid discharging from circular and elliptic nozzles with aspect ratios varying from 1.29 to 1.60. The diameter of the circular nozzle was 4.6 mm and the elliptic nozzles had approximately the same exit area as that of the circular nozzle. These non-circular nozzles were employed in order to increase the stability of attached jet diffusion flames. The time-averaged velocity and r.m.s. value of the velocity fluctuation in the streamwise and transverse directions were measured over the range of co-flowing stream velocities corresponding to different modes of flame blowout that are identified as either lifted or attached flames. On the basis of these measurements, attempts were made to explain the existence of an apparent optimum aspect ratio for the blowout of attached flames observed at higher values of co-flowing stream velocities. The insensitivity of the blowout limits of lifted flames to nozzle geometry observed in our previous work at low co-flowing stream velocities was also explained. Measurements of the fuel concentration at the jet centerline indicated that the mixing process was enhanced with the 1.38 aspect ratio jet compared with the 1.60 aspect ratio jet. On the basis of the obtained experimental data, it was suggested that the higher blowout limits of attached flames for an elliptic jet of 1.38 aspect ratio was due to higher entrainment rates.