Inverse convection problem of simultaneous estimation of two boundary heat fluxes in parallel plate channels

This paper deals with the use of the conjugate gradient method of function estimation for the simultaneous identification of two unknown boundary heat fluxes in parallel plate channels. The fluid flow is assumed to be laminar and hydrodynamically developed. Temperature measurements taken inside the channel are used in the inverse analysis. The accuracy of the present solution approach is examined by using simulated measurements containing random errors, for strict cases involving functional forms with discontinuities and sharp-corners for the unknown functions. Three different types of inverse problems are addressed in the paper, involving the estimation of: (i) Spatially dependent heat fluxes; (ii) Time-dependent heat fluxes; and (iii) Time and spatially dependent heat fluxes.

Screening the mutagenic activities of coomonly used antiparasite drugs by the Simultest, a simplified Salmonella/microsome plate incorporation assay

The mutagenic activities of 16 anti-parasite drugs were screened by the Simultest in both qualitative (spot test) and quantitative (plate incorporation) assays with a Salmonella typhimurium pool composed by the indicator strains TA97, TA 98, TA100 and TA102. Four anti Chagas' disease drugs (nifurtimox, benznidazole, CL 64,855, and MK 436) and two anti-amebae drugs (metronidazole and tinidazole) gave positive results in qualitative tests and incorporation of rat liver microsomes did not alter the results. Comparative dose response curves of the mutagenic activities of CL 64,855, metronidazole and benznidazole obtained by the simultest and by individual Salmonella indicator strains demonstrated that both approachs have similar sensitivities. The results corroborate the validity of the Simultest, as a simplified, fast and economic version of the Ames test in preliminary screening of potential mutagenic drugs.

Studies on prevalence of Strongyloides infection in Holambra and Maceió, Brazil, by the agar plate faecal culture method

Prevalence of Strongyloides stercoralis infection in three areas of Brazil was surveyed by a recently developed faecal culture method (an agar plate culture). The Strongyloides infection was confirmed in 11.3% of 432 subjects examined. The diagnostic efficacy of the agar plate culture was as high as 93.9% compared to only 28.5% and 26.5% by the Harada-Mori filter paper culture and faecal concentration methods, when faecal samples were examined simultaneously by these three methods. Among the 49 positive samples, about 60% were confirmed to be positive only by the agar plate culture. These results indicate that the agar plate culture is a sensitive new tool for the correct diagnosis of chronic Strongyloides infection.

Plate tectonics, seaways and climate in the historical biogeography of mammals

The marsupial and placental mammals originated at a time when the pattern of geographical barriers (oceans, shallow seas and mountains) was very different from that of today, and climates were warmer. The sequence of changes in these barriers, and their effects on the dispersal of the mammal families and on the faunas of mammals in the different continents, are reviewed. The mammal fauna of South America changed greatly in the Pliocene/Pleistocene, when the newly-complete Panama Isthmus allowed the North American fauna to enter the continent and replace most of the former South American mammal families. Marsupial, but not placental, mammals reached Australia via Antarctica before Australia became isolated, while rats and bats are the only placentals that dispersed naturally from Asia to Australia in the late Cenozoic. Little is known of the early history of the mammal fauna of India. A few mammal families reached Madagascar from Africa in the early Cenozoic over a chain of islands. Africa was isolated for much of the early Cenozoic, though some groups did succeed in entering from Europe. Before the climate cooled in the mid-Cenozoic, the mammal faunas of the Northern Hemisphere were much richer than those of today.

Cross-sectional study defines difference in malaria morbidity in two Yanomami communities on Amazonian boundary between Brazil and Venezuela

It is well established that immunity to malaria is short-lived and is maintained by the continuous contact with the parasite. We now show that the stable transmission of malaria in Yanomami Amerindian communities maintains a degree of immunity in the exposed population capable to reduce prevalence and morbidity of malaria. We examined 508 Yanomami Amerindians living along Orinoco (407) and Mucajaí (101) rivers, on the Venezuelan and Brazilian Amazon region, respectively. At Orinoco villages, malaria was hyperendemic and presented stable transmission, while at Mucajaí villages it was mesoendemic and showed unstable transmission. The frequency of Plasmodium vivax and P. falciparum was roughly comparable in Venezuelan and Brazilian communities. Malaria presented different profiles at Orinoco and Mucajaí villages. In the former communities, malaria showed a lower prevalence (16% x 40.6%), particularly among those over 10 years old (5.2% x 34.8%), a higher frequency of asymptomatic cases (38.5% x 4.9%), and a lower frequency of cases of severe malaria (9.2% x 36.5%). Orinoco villagers also showed a higher reactivity of the immune system, measured by the frequency of splenomegaly (72.4% x 29.7%) and by the splenic index (71.4% over level 1 x 28.6), and higher prevalence (91.1% x 72.1%) and mean titer (1243 x 62) of antiplasmodial IgG antibodies, as well as a higher prevalence (77.4% x 24.7%) and mean titer (120 x 35) of antiplasmodial IgM antibodies. Our findings show that in isolated Yanomami communities the stability of malaria transmission, and the consequent continuous activation of the immune system of the exposed population, leads to the reduction of malaria prevalence and morbidity.

Colorimetric microwell plate reverse-hybridization assay for Mycobacterium tuberculosis detection

Direct smear examination using Ziehl-Neelsen staining for pulmonary tuberculosis (PTB) diagnosis is inexpensive and easy to use, but has the major limitation of low sensitivity. Rapid molecular methods are becoming more widely available in centralized laboratories, but they depend on timely reporting of results and strict quality assurance obtainable only from costly commercial kits available in high burden nations. This study describes a pre-commercial colorimetric method, Detect-TB, for detecting Mycobacterium tuberculosis DNA in which an oligonucleotide probe is fixed onto wells of microwell plates and hybridized with biotinylated polymerase chain reaction amplification products derived from clinical samples. The probe is capable of hybridising with the IS6110 insertion element and was used to specifically recognise the M. tuberculosis complex. When combined with an improved silica-based DNA extraction method, the sensitivity of the test was 50 colony-forming units of the M. tuberculosis reference strain H37Rv. The results that were in agreement with reference detection methods were observed in 95.2% (453/476) of samples included in the analysis. Sensitivity and specificity for 301 induced sputum samples and 175 spontaneous sputum samples were 85% and 98%, and 94% and 100%, respectively. This colorimetric method showed similar specificity to that described for commercially available kits and may provide an important contribution for PTB diagnosis.

Numerical modeling of the effect of variation of boundary conditions on vadose zone hydraulic properties

An accurate estimation of hydraulic fluxes in the vadose zone is essential for the prediction of water, nutrient and contaminant transport in natural systems. The objective of this study was to simulate the effect of variation of boundary conditions on the estimation of hydraulic properties (i.e. water content, effective unsaturated hydraulic conductivity and hydraulic flux) in a one-dimensional unsaturated flow model domain. Unsaturated one-dimensional vertical water flow was simulated in a pure phase clay loam profile and in clay loam interlayered with silt loam distributed according to the third iteration of the Cantor Bar fractal object Simulations were performed using the numerical model Hydrus 1D. The upper and lower pressure heads were varied around average values of -55 cm for the near-saturation range. This resulted in combinations for the upper and lower constant head boundary conditions, respectively, of -50 and -60 cm, -40 and -70 cm, -30 and -80 cm, -20 and -90 cm, and -10 and -100 cm. For the drier range the average head between the upper and lower boundary conditions was set to -550 cm, resulting in the combinations -500 and -600 cm, -400 and -700 cm, -300 and -800 cm, -200 and -900 cm, and -100 and -1,000 cm, for upper and lower boundary conditions, respectively. There was an increase in water contents, fluxes and hydraulic conductivities with the increase in head difference between boundary conditions. Variation in boundary conditions in the pure phase and interlayered one-dimensional profiles caused significant deviations in fluxes, water contents and hydraulic conductivities compared to the simplest case (a head difference between the upper and lower constant head boundaries of 10 cm in the wetter range and 100 cm in the drier range).

Boundary between Soil and Saprolite in Alisols in the South of Brazil

Despite numerous studies conducted on the lower limit of soil and its contact with saprolite layers, a great deal of work is left to standardize identification and annotation of these variables in the field. In shallow soils, the appropriately noting these limits or contacts is essential for determining their behavior and potential use. The aims of this study were to identify and define the field contact and/or transition zone between soil and saprolite in profiles of an Alisol derived from fine sandstone and siltstone/claystone in subtropical southern Brazil and to subsequently validate the field observations through a multivariate analysis of laboratory analytical data. In the six Alisol profiles evaluated, the sequence of horizons found was A, Bt, C, and Cr, where C was considered part of the soil due to its pedogenetic structure, and Cr was considered saprolite due to its rock structure. The morphological properties that were determined in the field and that were different between the B and C horizons and the Cr layer were color, structure, texture, and fragments of saprolite. According to the test of means, the properties that support the inclusion of the C horizon as part of the soil are sand, clay, water-dispersible clay, silt/clay ratio, macroporosity, total porosity, resistance to penetration, cation exchange capacity, Fe extracted by DCB, Al, H+Al, and cation exchange capacity of clay. The properties that support the C horizon as a transition zone are silt, Ca, total organic C, and Fe extracted by ammonium oxalate. Discriminant analysis indicated differences among the three horizons evaluated.

Longitudinal distribution of bean seeds in horizontal plate meter operating with one or two seed outlets

This study aimed to evaluate the effect of horizontal plate meter with oblong holes operating with one or two seed outlets at different speeds over the accuracy of longitudinal distribution of common bean seeds (Phaseolus vulgaris L.). The experiment was performed in laboratory using the meter with one and two seed outlet points in relation to ten tangential disk plate speeds (0.03 to 0.30 m s-1). It was used a complete randomized design with four replications, summing up 80 experimental treatments. Tangential speed quantitative factor was estimated through a 2nd order polynomial regression. There was no significant difference in the behavior of the seed meter operating with one or two outlets in the metering of bean seeds in all tested speeds, with percentage of single seeds spacing over 60% in tangential speeds below of 0.24 m s-1.

Effects of hyperprolactinemia and ovariectomy on the tibial epiphyseal growth plate and bone formation in mice

PURPOSE: To evaluate the effects of ovariectomy and the hyperprolactinemia procedure in the tibial epiphyseal growth plate of female mice.METHODS: In this study, the epiphyseal growth plate of ovariectomized (OVX) and/or rendered hyperprolactinemic female mice by 50 days of treatment with 200 μg metoclopramide (M) was evaluated morphologically, morphometrically and immuno-histochemically. Forty female and adult mice were divided into four groups according to treatment: V group - animals treated with saline solution; H group - hyperprolactinemic animals; Ovx/V group - ovariectomized animals and treated with saline solution; Ovx/H group - hyperprolactinemic and ovariectomized animals. After the treatment period, the animals were sacrificed, tibia was removed and fixed in 10% buffered formalin and decalcified in 10% formic acid. The material was immersed in paraffin and subjected to histological processing in paraffin. The sections were stained with Masson's trichrome and immunohistochemistry was carried out for the pro-apoptotic protein BCL-2. The images for the morphological and morphometric study were analyzed with the imaging program AxioVision 4.8 (Carl-Zeiss(r), Germany).RESULTS: The combination of hyperprolactinemia and the ovariectomy procedure decreased the number of resting chondrocytes 1.5-fold, the number of proliferative chondrocytes 1.8-fold; the percentage of resting cartilage 2.4-fold and the percentage of trabecular bone 2.1-fold, compared with respective control animals.CONCLUSION: The procedure of ovariectomy combined with the metoclopramide-induced hyperprolactinemia in female mice has showed marked bone degeneration due to significant decrease of cell proliferation in the epiphyseal growth plate and bone formation.

Pressure drop coefficients for elliptic and circular sections in one, two and three-row arrangements of plate fin and tube heat exchangers

The objective of the present work is the experimental determination of pressure drop coefficients (loss coefficients) for elliptic and circular sections in one, two and three-row arrangements of plate fin and tube heat exchangers. The experiments permitted to correlate the dimensionless loss coefficient with the flow Reynolds number in the rectangular channel formed by the plate fins. The experimental technique consisted of the measurement of the longitudinal pressure distribution along the flow channel, for several values of air mass flow rate. The total number of data runs, each one characterized by the flow Reynolds number, was 216. The present geometry is used in compact heat exchangers for air conditioning systems, heaters, radiators, and others. Also, it is verified the influence of the utilization of elliptic tubes, instead of circular ones, in the pressure drop. The measurements were performed for Reynolds numbers ranging from 200 to 1900.

Effect of different surface roughnesses on a turbulent boundary layer

The classical treatment of rough wall turbulent boundary layers consists in determining the effect the roughness has on the mean velocity profile. This effect is usually described in terms of the roughness function delta U+. The general implication is that different roughness geometries with the same delta U+ will have similar turbulence characteristics, at least at a sufficient distance from the roughness elements. Measurements over two different surface geometries (a mesh roughness and spanwise circular rods regularly spaced in the streamwise direction) with nominally the same delta U+ indicate significant differences in the Reynolds stresses, especially those involving the wall-normal velocity fluctuation, over the outer region. The differences are such that the Reynolds stress anisotropy is smaller over the mesh roughness than the rod roughness. The Reynolds stress anisotropy is largest for a smooth wall. The small-scale anisotropy and interniittency exhibit much smaller differences when the Taylor microscale Reynolds number and the Kolmogorov-normalized mean shear are nominally the same. There is nonetheless evidence that the small-scale structure over the three-dimensional mesh roughness conforms more closely with isotropy than that over the rod-roughened and smooth walls.

An experimental/numerical study of the turbulent boundary layer development along a surface with a sudden change in roughness

A theory for the description of turbulent boundary layer flows over surfaces with a sudden change in roughness is considered. The theory resorts to the concept of displacement in origin to specify a wall function boundary condition for a kappa-epsilon model. An approximate algebraic expression for the displacement in origin is obtained from the experimental data by using the chart method of Perry and Joubert(J.F.M., vol. 17, pp. 193-122, 1963). This expression is subsequently included in the near wall logarithmic velocity profile, which is then adopted as a boundary condition for a kappa-epsilon modelling of the external flow. The results are compared with the lower atmospheric observations made by Bradley(Q. J. Roy. Meteo. Soc., vol. 94, pp. 361-379, 1968) as well as with velocity profiles extracted from a set of wind tunnel experiments carried out by Avelino et al.( 7th ENCIT, 1998). The measurements are found to be in good agreement with the theoretical computations. The skin-friction coefficient was calculated according to the chart method of Perry and Joubert(J.F.M., vol. 17, pp. 193-122, 1963) and to a balance of the integral momentum equation. In particular, the growth of the internal boundary layer thickness obtained from the numerical simulation is compared with predictions of the experimental data calculated by two methods, the "knee" point method and the "merge" point method.

The Shadow Moiré method using the phase shifting technique and digital image processing: computational implementation and application to the 3D-reconstruction of a buckled plate

The Shadow Moiré fringe patterns are level lines of equal depth generated by interference between a master grid and its shadow projected on the surface. In simplistic approach, the minimum error is about the order of the master grid pitch, that is, always larger than 0,1 mm, resulting in an experimental technique of low precision. The use of a phase shift increases the accuracy of the Shadow Moiré technique. The current work uses the phase shifting method to determine the surfaces three-dimensional shape using isothamic fringe patterns and digital image processing. The current study presents the method and applies it to images obtained by simulation for error evaluation, as well as to a buckled plate, obtaining excellent results. The method hands itself particularly useful to decrease the errors in the interpretation of the Moiré fringes that can adversely affect the calculations of displacements in pieces containing many concave and convex regions in relatively small areas.