Virtual States, Halos and Resonances in Three-Body Atomic and Nuclear Systems

By considering nuclear and ultracold trapped atomic systems, we review the trajectory of Efimov excited states in the complex plane by changing the two-body scattering lengths and one three-body scale.

On control and synchronization in chaotic and hyperchaotic systems via linear feedback control

This paper presents the control and synchronization of chaos by designing linear feedback controllers. The linear feedback control problem for nonlinear systems has been formulated under optimal control theory viewpoint. Asymptotic stability of the closed-loop nonlinear system is guaranteed by means of a Lyapunov function which can clearly be seen to be the solution of the Hamilton-Jacobi-Bellman equation thus guaranteeing both stability and optimality. The formulated theorem expresses explicitly the form of minimized functional and gives the sufficient conditions that allow using the linear feedback control for nonlinear system. The numerical simulations were provided in order to show the effectiveness of this method for the control of the chaotic Rossler system and synchronization of the hyperchaotic Rossler system. (C) 2007 Elsevier B.V. All rights reserved.

Surface structure and electronic properties of Pt-Fe/C nanocatalysts and their relation with catalytic activity for oxygen reduction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On the photoluminescence behavior of samarium-doped strontium titanate nanostructures under UV light. A structural and electronic understanding

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pollination and dispersal systems in a Cerrado remnant (Brazilian Savanna) in Southeastern Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Vegetative and productive aspects of organically grown coffee cultivars under shaded and unshaded systems

Although Coffea arabica species has its origin in the African understories, there is great resistance on the part of the Brazilian producers for growing this species under agroforestry systems as they fear that shading reduces production. This study aimed at evaluating some vegetative traits and the productivity of organically grown coffee (Coffea arabica L.) cultivars under shaded and unshaded systems. Twelve treatments consisting of two cultivation systems (shaded and unshaded) and six coffee cultivars were arranged in randomized blocks with four replicates, in a split-plot scheme. Shading was provided by banana (Musa sp.) and coral bean plants (Erythrinaverna). Shading delayed fruit maturation. Late maturation cultivars, such as the Icatu and the Obatã, matured early in both cultivation systems, while medium and early maturation cultivars presented late maturation. Cultivation in the shaded system increased the leaf area and the number of lower branches, decreased the number of productive nodes per branch, and increased the distance between the nodes and the number of leaves present in the branches. Cultivation in the unshaded system presented greater number of plants with branch blight in relation to plants grown in the shade. The productivity of the cultivars was not different, at 30.0 processed bags per hectare in the shaded system, and 25.8 processed bags per hectare in the unshaded system. The most productive cultivars in the shaded system were the Tupi, the Obatã, and the Catuaí, while no differences between cultivars were obtained in the unshaded system.

Characterization and catalytic activity of iron(III) mono(4-N-methyl pyridyl)-tris(halophenyl) porphyrins in homogeneous and heterogeneous systems

The synthesis, characterization and catalytic activity of the cationic iron porphyrins Fe[M(4-N-MePy)TDCPP]Cl-2 and Fe[M(4-N-MePy)TFPP]Cl-2 in the epoxidation of (Z)-cyclooctene by PhIO in homogeneous solution and supported on silica gel (SG), imidazole propyl gel (IPG) or SG modified with 2-(4-sulfonatophenyl)ethyl groups (SiSO3) have been accomplished. When supported on IPG, both cationic FeP bind to the support via Fe-imidazole coordination. Fe[M(4-N-MePy)TDCPP]IPG contains a mixture of low-spin bis-coordinated (FeP)-P-III and high-spin mono-coordinated (FeP)-P-III species, whereas Fe[M(4-N-MePy)TFPP]IPG only contains high-spin mono-coordinated (FeP)-P-III. These FePIPG catalysts also contain (FeP)-P-II species, whose presence was confirmed by EPR spectroscopy using NO as a paramagnetic probe. Both cationic FePs coordinate to SG through Fe-O ligation and they are present as high-spin (FeP)-P-III species. The cationic FePs supported on SiSO3- are also high-spin (FeP)-P-III species and they bind to the support via electrostatic interaction between the 4-N-methylpyridyl groups and the SO3- groups present on the matrix. In homogeneous solution, both Fe[M(4-N-MePy)TDCPP]Cl-2 and Fe[M(4-N-MePy)TFPP]Cl-2 have similar catalytic activity to Fe(TDCPP)Cl and Fe(TFPP)Cl, leading to cis-epoxycyclooctane yields of 92%. When supported on inorganic matrices,both FePs lead to epoxide yields comparable to their homogeneous analogues and their anchoring enables catalyst recovery and re-use. Recycling of Fe[M(4-N-MePy)TDCPP]SiSO3- shows that this FeP maintains its activity in a second reaction. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Relation between antioxidant activity and electronic structure of Phenols

We describe a new physicochemical descriptor of the antioxidant activity of phenols, the energy difference between the two highest occupied molecular orbitals, which we believe will improve quantitative structure-activity relationship studies about these compounds. (C) 2003 Wiley Periodicals, Inc.

Thermoeconomic analysis method for optimization of combined heat and power systems. Part I

This article presents a thermoeconomic analysis of cogeneration plants, applied as a rational technique to produce electric power and saturated steam. The aim of this new methodology is the minimum Exergetic Production Cost (EPC), based on the Second Law of Thermodynamics. The variables selected for the optimization are the pressure and the temperature of the steam leaving the boiler in the case of using steam turbine, and the pressure ratio, turbine exhaust temperature and mass flow in the case of using gas turbines. The equations for calculating the capital costs of the components and products are formulated as a function of these decision variables. An application of the method using real data of a multinational chemical industry located in São Paulo state is presented. The conditions which establish the minimum cost are presented as final output. (C) 2003 Elsevier Ltd. All rights reserved.

In vitro evaluation of root canal preparation using oscillatory and rotary systems in flattened root canals

Objective: the aim of this study was to evaluate the biomechanical preparation of flattened root canals using the following systems: Endo-Eze AET stainless steel oscillatory instruments (Ultradent) and RaCe rotary NiTi instruments (FKG Dentaire). Materials and Methods: Twenty extracted human mandibular incisors were randomly assigned to two groups: Group I Instrumentation with oscillatory Endo-Eze AET files (oscillatory technique); Group 2 - Instrumentation with rotary NiTi RaCe files (rotary technique). The teeth were decoronated, had their apices and coronal openings sealed with sticky wax and were embedded in crystal-clear orthophtalic polyester resin. The roots were sectioned transversally with diamond discs at 10 mm (middle third) and 5 mm (apical third) from the apex and the segments were reassembled for instrumentation. The sections were photographed before and after root canal instrumentation and evaluated with respect to whether the original root canal shape was modified by instrumentation. To evaluate the differences in the root canal shape before and after biomechanical preparation, scores were given regarding the instruments touch on the intracanal walls. Results: In middle third of the root canals instrumented with the rotary system, there was a change in the original canal anatomy (p < 0.05), with formation of a protuberance in the mesiodistal direction. This protuberance did not occur when the oscillatory instrumentation was used. The oscillatory system had better results in the middle and apical thirds as evaluated by Dunn's multiple-comparison test (p > 0.05). Conclusion: Under the tested conditions, Endo-Eze oscillatory system yielded the instrumentation of all flattened oot canal walls, maintaining the canal original shape throughout the biomechanical preparation, and was more effective than RaCe rotary system.

Oxytocinergic and serotonergic systems involvement in sodium intake regulation: satiety or hypertonicity markers?

Previous studies demonstrated the inhibitory participation of serotonergic ( 5-HT) and oxytocinergic (OT) neurons on sodium appetite induced by peritoneal dialysis (PD) in rats. The activity of 5-HT neurons increases after PD- induced 2% NaCl intake and decreases after sodium depletion; however, the activity of the OT neurons appears only after PD-induced 2% NaCl intake. To discriminate whether the differential activations of the 5-HT and OT neurons in this model are a consequence of the sodium satiation process or are the result of stimulation caused by the entry to the body of a hypertonic sodium solution during sodium access, we analyzed the number of Fos-5-HT- and Fos-OT-immunoreactive neurons in the dorsal raphe nucleus and the paraventricular nucleus of the hypothalamus-supraoptic nucleus, respectively, after isotonic vs. hypertonic NaCl intake induced by PD. We also studied the OT plasma levels after PD- induced isotonic or hypertonic NaCl intake. Sodium intake induced by PD significantly increased the number of Fos-5- HT cells, independently of the concentration of NaCl consumed. In contrast, the number of Fos-OT neurons increased after hypertonic NaCl intake, in both depleted and nondepleted animals. The OT plasma levels significantly increased only in the PD- induced 2% NaCl intake group in relation to others, showing a synergic effect of both factors. In summary, 5-HT neurons were activated after body sodium status was reestablished, suggesting that this system is activated under conditions of satiety. In terms of the OT system, both OT neural activity and OT plasma levels were increased by the entry of hypertonic NaCl solution during sodium consumption, suggesting that this system is involved in the processing of hyperosmotic signals.

Phenotypic methods and commercial systems for the discrimination between C-albicans and C-dubliniensis

Candida dubliniensis is a recently described Candida species associated with oral candidosis that exhibits a high degree of phenotypic similarity to Candida albicans. However, these species show differences in levels of resistance to antimycotic agents and ability to cause infections. Therefore, accurate clinical identification of C. dubliniensis and C. albicans species is important in order to treat oral candidal infections. Phenotypic identification methods are easy-to-use procedures for routine discrimination of oral isolates in the clinical microbiology laboratory. However, C. dubliniensis may be so far underreported in clinical samples because most currently used identification methods fail to recognize this yeast. Phenotypic methods depend on growth temperature, carbon source assimilation, chlamydospore and hyphal growth production, positive or negative growth on special media and intracellular enzyme production, among others. In this review, some phenotypic methods are presented with a special emphasis on the discrimination of C. dubliniensis and C. albicans.

A CASE tool for the modeling of methods and information systems

MODSI is a multi-models tool for information systems modeling. A modeling process in MODSI can be driven according to three different approaches: informal, semi-formal and formal. The MODSI tool is therefore based on the linked usage of these three modeling approaches. It can be employed at two different levels: the meta-modeling of a method and the modeling of an information system.In this paper we start presenting different types of modeling by making an analysis of their particular features. Then, we introduce the meta-model defined in our tool, as well as the tool functional architecture. Finally, we describe and illustrate the various usage levels of this tool.

Composition and electronic structure of Zn7-xMxSb2O12 (M = Ni and Co) spinel compounds

The relation between the composition and electronic structure of the perfectly inverse spinel compound Zn7-xMxSb2O12 (M = Ni and Co) has been studied by powder X-ray diffraction and X-ray photoelectron spectroscopy. Changes in the site occupancy are associated with shifts in the core levels as observed in the core level spectral analyses. The configuration of the density of states in the valence band due to the Co and Ni states can be observed in the valence band spectra. (C) 2004 Elsevier B.V. All rights reserved.