Vertical distribution of zooplankton in the water column of Lago Amapá, Rio Branco, Acre, Brazil

O objetivo desta investigação foi observar a distribuição vertical da comunidade do zooplâncton no Lago Amapá (10º2'36S e 67º50'24W), localizado na planície de inundação do Rio Acre. Amostragens foram conduzidas em três diferentes profundidades da coluna da água, considerando aspectos sazonais do zooplâncton, parâmetros físicos, químicos e biológicos. Coletas foram realizadas semanalmente com Garrafa de Van Dorn. As espécies apresentaram maiores concentrações no meio da coluna da água. Foram encontradas 38 espécies, assim distribuídas: Rotifera (30), Cladocera (5) e Cyclopoida (3). A temperatura da coluna da água em geral apresentou-se alta, em torno de 30ºC, com pequena variação, resultando em baixa viscosidade. O índice de Jaccard, comparando-se as três estações de coletas, demonstrou que durante a fase de águas baixas, as estações 1 e 3 foram as mais similares (Cj = 0.7058), especialmente no meio da coluna da água. Lago Amapá apresentou características em conformidade com o Modelo do Distúrbio Intermediário, favorecendo a colonização de grupos oportunistas, tais como rotíferos.

A política externa do Brasil no século XXI: os eixos combinados de cooperação horizontal e vertical

Avaliando a primeira década do século XXI, a política externa do Brasil tem passado por uma evolução significativa caracterizada por uma posição internacional e projeção de poder assertiva, dinamizando parcerias estratégicas com países desenvolvidos e emergentes. O objetivo deste artigo é analisar as prioridades desta agenda e os potenciais relacionados a estes esforços de cooperação bi e multilateral horizontal e vertical.

Morfologia comparativa e distribuição batimétrica de duas espécies de Ophiuroidea, na região costeira de Ubatuba

Durante o período de outubro de 1985 a julho de 1987, foram coletados 722 ofíuróides pertencentes às espécies Ophioderma januarii e Ophioplocus januarii, na costa do Estado de São Paulo. Realizou-se medidas do diâmetro do disco dos exemplares e estas variaram entre 10,5 e 21,5 mm para Ophioderma januarii e entre 2,6 e 21,5 mm, para Ophioplocus januarii. Foram efetuadas observações das características morfológicas externas dos indivíduos e posteriormente, organizadas séries de crescimento, com o intuito de evidenciar possíveis alterações. Verificou-se para Ophioderma januarii, variações na forma dos escudos, no número de papilas orais e de espinhos braquiais, na coloração da superfície dorsal do disco e das placas braquiais dorsais e para Ophioplocus januarii variações nas escamas primárias, na série de escamas maiores da região interradial dorsal do disco, no número de escamas entre a centro-dorsal e a margem do disco, na forma dos escudos radiais e orais, no número de papilas orais, na coloração da superfície dorsal do disco e das placas braquiais dorsais. O resultado das análises de parâmetros ambientais dos locais de coleta, mostrou que as duas espécies ocorreram em áreas com condições ambientais distintas. Ophioderma januarii foi amostrada na região costeira até 36 m de profundidade e Ophioplocus januarii entre 30 e 100 m.

Distribuição do macrozoobentos na coluna vertical dos sedimentos da região estuarina de Cananéia (SP), Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

MECHANISM OF ACTION OF COBALT IONS ON RAT OSSEOUS PLATE ALKALINE-PHOSPHATASE

Polidocanol-solubilized osseous plate alkaline phosphatase was modulated by cobalt ions in a similar way as by magnesium ions. For concentrations up to 1 mu M, the Chelex-treated enzyme was stimulated by cobalt ions, showing K-d = 6.0 mu M, V = 977.5 U/mg, and site-site interactions (n = 2.5). Cobalt-enzyme was highly unstable at 37 degrees C, following a biphasic inactivation process with inactivation constants of about 0.0625 and 0.0015 min(-1). Cobalt ions stimulated the enzyme synergistically in the presence of magnesium ions (K-d = 5.0 mu M; V = 883.0 U/mg) or in the presence of zinc ions (K-d = 75.0 mu M; V = 1102 U/mg). A steady-state kinetic model for the modulation of enzyme activity by cobalt ions is proposed.

Dependence of divalent metal ions on phosphotransferase activity of osseous plate alkaline phosphatase

Kinetic evidence for the role of divalent metal ions in the phosphotransferase activity of polidocanol-solubilized alkaline phosphatase from osseous plate is reported. Ethylenediamine tetreacetate, 1,10-phenanthrolin, and Chelex-100 were used to prepare metal-depleted alkaline phosphatase. Except for Chelex-100, either irreversible inactivation of the enzyme or incomplete removal of metal ions occurred. After Chelex-100 treatment, full hydrolase activity of alkaline phosphatase was recovered upon addition of metal ions. on the other hand, only 20% of transferase activity was restored with 0.1 mu M ZnCl2, in the presence of 1.0 M diethanolamine as phosphate acceptor. In the presence of 0.1 mM MgCl2, the recovery of transferase activity increased to 63%. Independently of the phosphate acceptor used, the transferase activity of the metal-depleted alkaline phosphatase was fully restored by 8 mu M ZnCl2 plus 5 mM MgCl2. In the presence of diethanolamine as phosphate acceptor, manganese, cobalt, and calcium ions did nor stimulate the transferase activity. However, manganese and cobalt-enzyme catalyzed the transfer of phosphate to glycerol and glucose. (C) 1997 Elsevier B.V.

ALLOSTERIC MODULATION BY ATP, CALCIUM AND MAGNESIUM-IONS OF RAT OSSEOUS PLATE ALKALINE-PHOSPHATASE

Alkaline phosphatase from rat osseous plate is allosterically modulated by ATP, calcium and magnesium at pH 7.5. At pH 9.4, the hydrolysis of ATP and PNPP follows Michaelis-Menten kinetics with K0.5 values of 154 muM and 42 muM, respectively. However, at pH 7.5 both substrates exhibit more complex saturation curves, while only ATP exhibited site-site interactions. Ca2+-ATP and Mg2+-ATP were effective substrates for the enzyme, while the specific activity of the enzyme for the hydrolysis of ATP at pH 7.5 was 800-900 U/mg and was independent of the ion species. ATP, but not PNPP, was hydrolyzed slowly in the absence of metal ions with a specific activity of 140 U/mg. These data demonstrate that in vitro and at pH 7.5 rat osseous plate alkaline phosphatase is an active calcium or magnesium-activated ATPase.

Pechini's solution as precursor for Eu(III)-containing ZnO films

The flat-panel-display's (FPD) market and demand for highly efficient and colored luminescent films have been growing quickly. In this work, thin films were obtained from Pechini's solution by dip-coating. The green films were thermally treated at 873 K in order to get ZnO:Eu 1 at% thin film. A Schott(R) glass plate hydrothermally treated was used as substrate. The films have a mosaic shaped feature that was observed by optical microscopy. That feature is a result of substrate thermal treatment. The film deposition decreases the substrate transmittance in the visible range. When the F-7(0) -->L-5(6) (392nm) Eu3+ transition is excited, it is possible to detect emission from D-5(0) --> F-7(J) (J = 1, 2, 3 and 4) transitions. The D-5(0) --> F-7(2) transition is also observed by using ZnO excitation wavelengths indicating energy transfer from ZnO to Eu3+ ion. (C) 2003 Elsevier B.V. (USA). All rights reserved.

Non-newtonian heat transfer on a plate heat exchanger with generalized configurations

For the configuration optimization of plate heat exchangers (PHEs), the mathematical models for heat transfer and pressure drop must be valid for a wide range of operational conditions of all configurations of the exchanger or the design results may be compromised. In this investigation, the thermal model of a PHE is adjusted to fit experimental data obtained from non-Newtonian heat transfer for eight different configurations, using carboxymethylcellulose solutions (CMC) as test fluid. Although it is possible to successfully adjust the model parameters, Newtonian and non-Newtonian heat transfer cannot be represented by a single generalized correlation. In addition, the specific heat, thermal conductivity and power-law rheological parameters of CMC solutions were correlated with temperature, over a range compatible with a continuous pasteurization process.

Tibial segmental bone defect treated with bone plate and cage filled with either xenogeneic composite or autologous cortical bone graft

Tibia segmental defect healing in sheep were clinically, radiographically and histologically evaluated. Twelve young sheep aged four to five months were divided into two groups, G1 and G2. A 3.5 cm long segmental defect was created in the right tibial diaphysis with maintenance of the periosteum. The bone defects in both groups were stabilized with a bone plate combined with a titanium cage. In G1 the cage was filled with pieces of autologous cortical bone graft. In G2 it was filled with a composite biomaterial which consisted of inorganic bovine bone, demineralized bovine bone, a pool of bovine bone morphogenetic proteins bound to absorbable ultra-thin powdered hydroxyapatiteand bone-derived denaturized collagen. Except for one G1 animal, all of them showed normal limb function 60 days after surgery. Radiographic examination showed initial formation of periosteal callus in both groups at osteo-tomy sites, over the plate or cage 15 days postoperatively. At 60 and 90 days callus remodeling occurred. Histological and morphometric analysis at 90 days after surgery showed that the quantity of implanted materials in G1 and G2 were similar, and the quantity of new bone formation was less (p = 0.0048) and more immature in G1 than G2, occupying 51 +/- 3.46% and 62 +/- 6.26% of the cage space, respectively. These results suggest that the composite biomaterial tested was a good alternative to autologous cartical bone graft in this experimental ovine tibial defect. However, additional evaluation is warranted prior to its clinical usage.

Distribuição vertical, danos e controle cultural de Stenoma catenifer Walsingham (Lepidoptera: Elachistidae) em pomar de abacate

Stenoma catenifer Walsingham is the major pest in avocado groves (Persea americana Mill.) in the Neotropical region. Management has been difficult for many reasons related to the reduced knowledge on its bioecology and the avocado growing systems. The goal of this work was to study the vertical distribution of S. catenifer in avocado plants, the gagging effect of infested fruit on its survival, and the losses caused. The experiments were conducted in a commercial grove located at the Sao Tomas de Aquino, State of Minas Gerais, Brazil, during the 2001/2002 and 2002/2003 growing season. S. catenifer was observed especially at the lower and central part of the plant, and the inner canopy was the least attacked in comparison with the north, south, east and west quadrants. These results may be important indicators for the use of am adequate sampling procedure. The highest percentage of attacked fruit had one to four larvae; in some cases up to eight individuals per fruit were found. The losses caused by the borer varied during the agricultural season, with figures close to 5% in a single evaluation, and the harvest loss may reach 27%. The bagging of infested fruit caused mortality of S. catenifer, as observed through the evaluation carried out four days later.

Vertical marginal discrepancy of ceramic copings with different ceramic materials finish lines and luting agents: An in vitro evaluation

Statement of problem. Prosthetic restorations that fit poorly may affect periodontal health and occlusion. Studies that have evaluated the accuracy of fit of ceramic restorations before and after cementation assessed primarily intracoronal restorations.Purpose. This in vitro study evaluated the effect of different finish lines, ceramic manufacturing techniques, and luting agents on the vertical discrepancy of ceramic copings.Material and methods. Two stainless steel molars were prepared for complete crowns with 2 different finish lines (heavy chamfer and rounded shoulder); each molar was duplicated to fabricate 90 copings. A total of 180 copings generated 18 groups (n=10 for each finish line-coping material-luting agent combination). Luting agents tested included zinc phosphate, resin-modified glass ionomer (Fuji Plus), and resin composite cements (Panavia F). A metal frame was developed on which to screw the stainless steel model and a ceramic coping; the distance (mum) between 2 predetermined points was measured before and after cementation by a profile projector under a torquing force. A 4-way ANOVA with repeated measurements was performed to assess the influence of each factor in the vertical marginal discrepancy: 3 between-coping factors (finish line-coping material-luting agent) and 1 within-coping factor (before and after cementation) (alpha=.05).Results. Procera copings presented the lowest mean values (P<.05) of vertical marginal discrepancy before and after cementation (25/44 mum) when compared to Empress 2 (68/110 mum) and InCeram Alumina copings (57/117 mum), regardless of any combinations among all finish lines and luting agents tested.Conclusion. Considering each factor separately, the ceramic manufacturing technique appeared to be the most important factor tested for the definitive vertical discrepancy of all-ceramic copings, with lower mean values for Procera copings.