Interações do ácido indolil-3-acético e calcio sobre o fluxo de água de células de Nitella

The effect of indol-3-acetic acid (lAA) and calcium (Ca + + ) on the flow of water through Nitella celIs was studied. Nitella cernua Braun was selected because it is possible tb study the permeability of a single isolated cell. IAA was used at a concentration of 0,28 10-3 M and CaCI2 at 10-3 M. The effect of IAA on the isolated celIs was confirmed by the increase of plasticity and permeability of the plasmalema of th.e treated cells with absorption and a consequent elimination of water. The effect was reversed by Ca ions.

Relação entre o fluxo luminoso interceptado em diferentes épocas no índice de área foliar de diferentes forrageiras

The objective was to evaluate the leaf area index of six different grasses. The experiment was installed at the Instituto Federal de Tecnologia e Educacao of Uberaba, using a randomized block design with split plots in time. The plots were sown: Brachiaria decumbens cv. Basilisk, Brachiaria brizantha cv. Marandu, Panicum maximum cv. Mombasa, Panicum maximum cv. Tanzania, Brachiaria brizantha cv. Xaraes, Cynodon dactylon hb. Tifton and the plots, ten seasons of evaluation in 10 x 6 factorial arrangement with four replications. Rates of leaf area of each forage at different times of year were evaluated. Compared to other forage species, Panicum maximum had a higher leaf area index when subjected to periodic fertilization and irrigation. Only in the late fall Brachiaria Xaraes IAF had increased, but did not differ significantly from the others.

Efeitos do pentobarbital sódico sobre o fluxo sanguíneo renal. Estudo experimental no cão

In six dogs, previously anesthetized with sodium pentobarbital (30 mg/kg) for surgical preparation, catheterism and monitoring, the action of sodium pentobarbital (7,5 mg/kg) on renal flow was studied. Determinations of mean arterial pressure, venous pressure, cardiac rate, arterio-cava pressure gradient and renal arterial resistance were made. Pentobarbital doesn't change significantly the renal blood flow or any of the other parameters studied, with the exception of venous pressure in the inferior caval vein where the drug produces a significant fall.

Simulação numérica de trocadores de calor multitubulares equipados com fitas helicoidais externamente aos tubos

Classical shell-and-tube heat exchangers are usually equipped with segmental baffles. These baffles serve two basic functions: (a) they provide tube supports, thereby preventing or reducing mechanical problems, such as sagging or vibration; (b) they direct the fluid flow over the tubes so as to introduce a cross-flow component, thereby increasing the heat transfer. Segmented baffles have several sources of performance loss, some due to various leakage flows and others caused by stagnation zones. A new concept of longitudinal flow heat exchanger - based on placing twisted tapes along the tube bundle subchannels - was developed to mitigate drawbacks of other types of tubular heat exchangers. In this paper, a numerical model has been implemented in order to simulate the thermal-hydraulic feature of tubular heat exchangers equipped either with segmental baffles or with subchannel twisted tapes. The tube bundle has been described by means of an equivalent porous medium type model, allowing a macroscopic description of the shell-side flow. The basic equations - continuity, momentum and energy - have been solved by using the finite volume method. Typical numerical results have been compared with experimental data, reaching a very good agreement. A comparative analysis of different types of heat exchangers has been carried out, revealing the satisfactory thermal-hydraulic efficiency level of the twisted tapes heat exchangers.

Efeito do Nível de Energia da Dieta e da Exposição Prévia ao Calor sobre a Respiração Mitocondrial do Músculo Cardíaco de Frangos de Corte

This work was conducted aiming to evaluate the effect of dietary energy level and the previous heat exposure on the respiratory activity of the mitochondria from the cardiac muscle of broiler chickens. It was used broiler chickens (Hubbard) from both sexes and fed with diet containing 2900 kcal ME/kg or 3200 kcal ME/kg. The birds were heat stressed (35°C/4h) in the 1 st, 21 st and 42 nd days of age. The respiratory activity of mitochondria from cardiac muscle was evaluated in a Gilson oxygraph, model 5/6, by using alpha-ceto-glutaric as substrate and the ADP (adenosine-di-phosphate) to stimulate the respiratory activity. There was not effect of dietary energy level and previous heat exposure on the respiratory activity of the mitochondria from cardiac muscle. However, the females presented higher respiratory activity than males. By reason of the low oxidative capability of the heart muscle fiber of the male broiler chickens, these could be more sensitive to cardiac disease than females.

Efeito do extrato aquoso de sete-sangrias [Cuphea mesostemon (Koehne) Lourt] sobre o fluxo de água, medido em bexiga urinária de sapo in vitro

The Cuphea mesostemon specie, known as sete-sangrias, is widely used as a diuretic substance in popular medicine. As the toad urinary bladder is an epithelium analogous to the distal nephron of mammals, it is used in order to study the transport water and electrolytes in many laboratories. This preparation permits excellent observation in water flow, from the urinary bladder lumen to the external side or the serosal one (water re-absorption), by means of gravimetrical measures. In the present work the hydrosmotic effect of aqueous extract (AE) of sete-sangrias leaf was studied. A 20% solution was added to the serosal side (S) of the bladder preparation, and the water flow was measured every 15 minutes after that. The results showed that 4mL of AE in the S side, increased the JH20 in a significant manner (p<0,05). This effect had a dose - response shape, with the volumes of 0,2mL, 0,4mL and 0,8mL of AE in the S bath. The hydro-osmotic effect of the anti-diuretic hormone (ADH) was studied as well and a significant stimulation (p<0,05) in the JH2O was observed with the magnitude of 150%. The AE effect was similar to the ADH one, and was not antagonized by this hormone. We concluded that Cuphea possesses an anti-diuretic activity similar to that presented by ADH, in toad urinary bladder, in vitro.

Estudo do calo sensível e latente obtidos por intermédio da razão de Bowen em uma cultura de soja irrigada

The goal of this experiment was to study the latent and sensible heat variation determined by Bowen ratio from an irrigated soybean crop. A micrometeorological station with vertical displacement was constructed to maintain the same level of all measures over the canopy. The station was installed in the center of the crop, and it was over 130 m away from the main edge of the predominant wind direction. Fluxes were calculated by vertical temperature gradient determined at 0.15 and 1.15 m over the canopy. The latent heat flux was the mean energy consumer when the canopy covered the soil totally, and there were good soil water conditions. The sensible heat flux was greater when the soil was not totally covered by the canopy. The canopy was essential on the amount of latent heat dissipated by the crop.

Diferentes procedimentos na determinação de indicadores internos para estimativa de produção fecal e fluxo duodenal de matéria seca em bovinos

Times of in situ incubation (144 and 288h) for determination of internal markers IADF and INDF and the effects of differents procedures (wash or not the nylon bag every 72h incubation) was evaluated in samples of diet, duodenal digesta and cattle feces. The duodenal flow dry matter and fecal production utilizing the internal markers to compare with the external marker chromium oxide there was estimated. The animals were fed with sorgum silage, concentrate or urea. In this experiment, a latin square design was used, in a factorial scheme (two times of incubation × two processing nylon bag). No was observed effect of the incubation time or processing in the internal markers INDF and IADF concentration and the in situ incubation after 144h is adequate to reproduce the indigestible markers fraction in samples. For fecal production estimation, the external marker chromium oxide presented similar result (1.26 kg day-1) as the total fecal collection (1.49 kg day-1). Both the internal markers overestimate the duodenal flow dry matter when compared with the external marker chromium oxide.

Indicadores na estimativa do fluxo de digesta em bovinos de corte

single and double marker methods were compared in seven Nellore steers with average body weight 250 kg, and previously canullated in the rumen and duodenum. The animals were fitted with continuous-infusion pump that administered CoEDTA solutions intraruminally. In addition, a capsule containing Cr 2O 3, and other, containing external n-alkanes C 32, C 36 were inserted into the rumen of each steer. Internal markers indigestible neutral-detergent fiber and acid-detergent fiber (iNDF and iADF after 144 h in situ incubation) and internal n-alkanes C 31, C 33, C 35 were components of the diet. Steers were fed with palisade grass (Brachiaria brizantha cv. marandu) in two age of regrowth, 30 and 60 days. The duodenal flow experimental design was a factorial 2×2×12 while omasal experimental design was a factorial 2×2×4. Markers iNDF, CoEDTA and the combination Co+iNDF were efficacious to estimate duodenal dry matter flow whereas iNDF, iADF and the Co+iADF combination were all efficacious to predict omasal dry matter flow. In conclusion, the double marker method for estimation of omasal and duodenal dry matter flow was the most appropriate considering the ruminal fiber digestibility.

Fluxo de potência trifásico probabilístico para redes de distribuição usando o método de estimação por pontos

In this paper the point estimation method is applied to solve the probabilistic power flow problem for unbalanced three-phase distribution systems. Through the implementation of this method the probability distribution functions of voltages (magnitude and angle) as well as the active and reactive power flows in the branches of the distribution system are determined. Two different approaches of the point estimation method are presented (2m and 2m+1 point schemes). In order to test the proposed methodology, the IEEE 34 and 123 bus test systems are used. The results obtained with both schemes are compared with the ones obtained by a Monte Carlo Simulation (MCS).

Avaliação leucocitária de cães com linfoma submetidos ao protocolo de Madison-Wisconsin pela técnica convencional e citometria de fluxo

Lymphoma is the most common hematopoietic tumor in dogs and one of the malignant tumors with higher occurrence in this species. It is a great experimental model due to its resemblance with the non-Hodgkin lymphoma in humans. Considering the importance of the overall changes that result from to this kind of neoplastic tumor and those due to polichemotherapy this study aimed to evaluate the absolute leukon count and the total count of CD45+ cells in the blood of 25 dogs with lymphoma. Findings were crosschecked since diagnose and then once weekly during the first eight sessions of the Madison-Wisconsin chemotherapic protocol. Total granulocyte, lymphocyte and monocyte counts obtained from a conventional automatic counter and by flow cytometry were compared. Results did not reveal statistically significant changes between the two techniques.

Eficácia de fluridone para o controle de Egeria spp. em caixas d'água e em represa de pequeno porte sem fluxo de água

Pós-graduação em Agronomia (Agricultura) - FCA

Retenção do cátion do sulfato de cobre nos compartimentos biótico e abiótico de mesocosmos com sistema de fluxo contínuo de água

Pós-graduação em Aquicultura - FCAV

Aplicação do método de Newton desacoplado para o fluxo de carga continuado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fluxo de carga continuado considerando o controle de intercâmbio entre áreas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)