Carbon sources and trophic position of the main species of fishes of Baía River, Paraná River floodplain, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Bibliometrics Contribution to the Metatheoretical and Domain Analysis Studies

Along with the growth of scientific production, the bibliometric studies have become essential, providing relevant information about any domain while identifying, highlighting and viewing the scientific knowledge constructed within a theme, subject or knowledge area. This article approaches the bibliometric studies under the light of metatheory and domain analysis within the knowledge organization in information science. domain analysis and metatheory are considered significant contribution to bibliometric studies when emphasizing the need for epistemological, sociological and historical analyzes, as well as other qualitative approaches, encouraging researchers to reflect on the whole composition of the research object, by means of different methodological, theoretical and epistemological approaches. This study aims at contributing to the discourse of the theoretical aspects of bibliometric studies by presenting considerations concerning Hjorland's domain analysis, as well as Ritzer's metatheoretical approach, featuring discussions on major theories of a study field, since these approaches together provide a more complete qualitative view upon an area, here, represented by the bibliometric studies.

A contribution for thermoeconomic modelling: A methodology proposal

This work presents a thermoeconomic optimization methodology for the analysis and design of energy systems. This methodology involves economic aspects related to the exergy conception, in order to develop a tool to assist the equipment selection, operation mode choice as well as to optimize the thermal plants design. It also presents the concepts related to exergy in a general scope and in thermoeconomics which combines the thermal sciences principles (thermodynamics, heat transfer, and fluid mechanics) and the economic engineering in order to rationalize energy systems investment decisions, development and operation. Even in this paper, it develops a thermoeconomic methodology through the use of a simple mathematical model, involving thermodynamics parameters and costs evaluation, also defining the objective function as the exergetic production cost. The optimization problem evaluation is developed for two energy systems. First is applied to a steam compression refrigeration system and then to a cogeneration system using backpressure steam turbine. (C) 2010 Elsevier Ltd. All rights reserved.

Influence of Implant Design on the Biomechanical Environment of Immediately Placed Implants: Computed Tomography-Based Nonlinear Three-Dimensional Finite Element Analysis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Biomechanical Evaluation of Platform Switching in Different Implant Protocols: Computed Tomography-Based Three-Dimensional Finite Element Analysis

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

Influence of Implant Connection Type on the Biomechanical Environment of Immediately Placed Implants - CT-Based Nonlinear, Three-Dimensional Finite Element Analysis

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

Analysis of plant LTR-retrotransposons at the fine-scale family level reveals individual molecular patterns

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

Karyotypic diversification and its contribution to the taxonomy of Eleocharis (Cyperaceae) from Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Contribution of sugar-cane harvesting season to atmospheric contamination by polycyclic aromatic hydrocarbons (PAHs) in Araraquara city, Southeast Brazil

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

A Contribution to the Estimation of Binary Halide and Pseudo-Halide Equilibrium Constants using a Linear Extrapolation Methodology

The molar single ion activity coefficient (y(F)) of fluoride ions was determined at 25 degrees C and ionic strengths between 0.100 and 3.00 mol L(-1) NaClO(4) using an ion-selective electrode. The activity coefficient dependency on ionic strength was determined to be Phi(F) = log y(F) = 0.2315I-0.041I(2). The function Phi(F)(I), combined with functions obtained in previous work for copper (Phi(Cu)) and hydrogen (Phi(H)), allowed us to make the estimation of the stoichiometric and thermodynamic protonation constants of some halides and pseudo-halides as well as the formation constants of some pseudo-halides and fluoride 1:1 bivalent cation complexes. The calculation procedure proposed in this paper is consistent with critically-selected experimental data. It was demonstrated that it is possible to use Phi(F)(I) for predicting the thermodynamic equilibrium parameters independently of Pearson's hardness of acids and bases.

Dielectric spectroscopy analysis of CaCu3Ti4O12 polycrystalline systems

Dielectric spectroscopy was used in this study to examine CaCu3Ti4O12 polycrystalline samples. The analysis involved systems presenting low non-Ohmic properties, and the grain's internal domain was evaluated separately from the contribution of barrier-layer capacitances associated with Schottky-type barriers in this type of material. The effect of oxygen-rich atmosphere and high cooling rate was evaluated, revealing a strong increase in the dielectric properties of the CaCu3Ti4O12 system under these conditions. This effect was attributed to a chemical change in the grain's internal domain, which may be considered an internal barrier-layer capacitance of the polycrystalline material. (c) 2006 American Institute of Physics.

Determination of the relative contribution of phenolic antioxidants in orange juice by voltammetric methods

The electrochemical oxidation of caffeic, chlorogenic, sinapic, ferulic and p-coumaric acids was investigated by cyclic voltammetry on acetate buffer pH 5.6 on glassy carbon electrode and modified glassy carbon electrode. According to their voltammetric behavior, the antioxidant activity of these phenolic acids was evaluated and the results pointed to the following sequence: caffeic acid (E-a = +0.31 V) > chlorogenic acid (+ 0.38 V) > sinapic acid (+ 0.45 V) > ferulic acid (+ 0.53 V) >p-coumaric acid (+ 0.73 V). The results were confirmed by DPPH test, which evidenced the strongest antiradical activity for compounds possessing the cathecol moiety (caffeic and chlorogenic acids). Linear calibration graphs were obtained for their determination at concentrations from 1 x 10(-4) to 1 x 10(-3) mol L-1. The method was applied to orange juice. Selectivity was illustrated by the analysis of caffeic and chlorogenic acids electrodeposited on a glassy carbon electrode previously modified by electrochemical activation in the presence of ascorbic acid. (C) 2003 Elsevier B.V. All rights reserved.

CONTRIBUTION TO THE STUDY OF ZIRCONIUM AND HAFNIUM ALPHA-HYDROXYCARBOXYLATES

A study of both zirconium and hafnium alpha-hydroxycarboxylates for analytical applications is presented, These compounds are studied by infrared spectroscopy, thermal analysis and X-ray diffractometry. dl-Mandelic, dl-p-bromomandelic and dl-2-naphthylglycolic acids are the more adequate reagents for gravimetric determinations of zirconium and hafnium, the ligands dl-2-hydroxyhexanoic and dl-2-hydroxydodecanoic acids were used for the first time and the results showed that they are also adequate reagents for the same purpose.

REEVALUATION OF CHLORIDES REGULATION OF HEMOGLOBIN OXYGEN-UPTAKE - THE NEGLECTED CONTRIBUTION OF PROTEIN HYDRATION IN ALLOSTERISM

We have measured hemoglobin oxygen uptake vs. The partial pressure of oxygen, with independently controlled activities of chloride and water. This control is effected by combining different concentrations of NaCl and sucrose in the bathing solution to achieve: (i) water activities were varied and CI- activity was fixed, (ii) both water and CI- activities were varied with a traditional NaCI titration, or (iii) CI- activities were varied and water activity was fixed by adding compensating sucrose. Within this analysis, the CI--regulated loading of four oxygens can be described by the reaction Hb.CI- + 4 O-2 + 65 H2O reversible arrow Hb.4O(2).65H(2)O + CI-. The dissociation of a neatly integral chloride, rather than the nonintegral 1.6 chlorides inferred earlier from simple salt titration, demonstrates the need to recognize the potentially large contribution from changes in water activity when titrating weakly binding solutes. The single-chloride result might simplify structural considerations of the action of CI- in hemoglobin regulation.