Authors:M. Fassbender, H. Bach, E. Bond, F. Nortier, and D. Vieira
A simple method for the electrodeposition of elemental arsenic (As) on a metal backing from aqueous solutions has been developed.
The method was successfully applied to stable As (75As). Thin (2.5 mg cm−2) coherent, smooth layers of the metalloid on Ti foils (2.5 μm thickness) were obtained. Electrodeposits served as targets
for 75As(n,γ) 76As neutron capture experiments at Los Alamos Neutron Science Center (LANSCE). Respective 73As(n,γ) 74As experiments are planned for the near future, and 73As targets will be prepared in a similar fashion utilizing the new electrodeposition method. The preparation of an 73As (half-life 80.3 days) plating bath solution from proton irradiated germanium has been demonstrated. Germanium target irradiation
was performed at the Los Alamos Isotope Production Facility (IPF).
Authors:Karine O. Moura, Eunice F. S. Vieira, and Antonio R. Cestari
Here, we report for the first time the direct and simultaneous determination of kinetic and energetic parameters of Cr(VI) sorption on chemically modified fish scales (GA-scale) using solution microcalorimetry. Characterization has suggested that electrostatic interactions between scales collagen positive charges and chromate negative charges constitute the majority of the interactions. The microcalorimetric kinetic data of Cr(VI) sorption on GA-scale were successful adjusted to a three-parameter exponential function. The enthalpies of Cr(VI) sorption on GA-scale are highly exothermic (from −226.43 to −183.79 kJ mol−1), and Cr(VI) interaction energies decrease as initial Cr(VI) in solution increases. The kinetic and thermodynamic from solution microcalorimetry results suggest that the interactions GA-scale/Cr(VI) occur mainly by surface reactions. The maximum adsorption capacity of GA-scale for Cr(VI) was found to be comparable with some commercial adsorbent samples.
Authors:G. Wosiacki, A. Nogueira, N. Silva, F. Denardi, and R. Vieira
Brazilian pomiculture has definitively been established in the beginning of the 1970s as a result of a joined work of political, industrial and research sectors. After almost 35 years, one can see that this agricultural activity has modified many places in the Southern States of Brazil from both the social and the economical point of view. Such a modification can be observed especially in Fraiburgo, the epicentre of the apple cultivation in Santa Catarina, where even the landscape is completely different nowadays. During the last 23 years, the quality of samples of both commercial and experimental apples harvested at the median stage of the crop has been analysed according to the physicochemical parameters and the results were used to construct a database, which is described and partially shown in this paper. Brazil has recently been considered as member of the top apple producing countries in the world.
Authors:Elizabeth S. Vieira and José A. N. F. Gomes
The assessment of individual researchers using bibliometric indicators is more complex than that of a region, country or university. For large scientific bodies, averages over a large number of researchers and their outputs is generally believed to give indication of the quality of the research work. For an individual, the detailed peer evaluation of his research outputs is required and, even this, may fail in the short term to make a final, long term assessment of the relevance and originality of the work. Scientometrics assessment at individual level is not an easy task not only due to the smaller number of publications that are being evaluated, but other factors can influence significantly the bibliometric indicators applied. Citation practices vary widely among disciplines and sub disciplines and this may justify the lack of good bibliometric indicators at individual level. The main goal of this study was to develop an indicator that considers in its calculation some of the aspects that we must take into account on the assessment of scientific performance at individual level. The indicator developed, the hnf index, considers the different cultures of citation of each field and the number of authors per publication. The results showed that the hnf index can be used on the assessment of scientific performance of individual researchers and for following the performance of a researcher.
Authors:Elizabeth S. Vieira and José A. N. F. Gomes
This paper presents the journal relative impact (JRI), an indicator for scientific evaluation of journals. The JRI considers in its calculation the different culture of citations presented by the Web of Science subject categories. The JRI is calculated considering a variable citation window. This citation window is defined taking into account the time required by each subject category for the maturation of citations. The type of document considered in each subject category depends on its outputs in relation to the citations. The scientific performance of each journal in relation to each subject category that it belongs to is considered allowing the comparison of the scientific performance of journals from different fields. The results obtained show that the JRI can be used for the assessment of the scientific performance of a given journal and that the SJR and SNIP should be used to complement the information provided by the JRI. The JRI presents good features as stability over time and predictability.
Authors:M. C. Freitas, A. M. G. Pacheco, B. J. Vieira, and A. F. Rodrigues
Within an extensive survey of lower and higher plants in the Azores' Terceira and Santa Maria islands, this study is focused
on the evaluation of ectohydric bryophytes and bark from Cryptomeria japonica as an alternative to epiphytic lichens for air-monitoring purposes. Neutron activation analysis (k0-NAA) has been applied to all field samples for elemental determinations. Judging from the present results, and since the
islands embody most features of the whole archipelago, bryophytes do not appear as an option for further campaigns in the
Azores, due to scanty supply and relatively poor performance as biomonitors. On the other hand, comparisons of bark with lichens
collected at the same sites seem fairly good, and elements are enriched in bark to an even greater extent than in lichens.
All things considered - including material availability and ecological concern - bark stands for a sensible choice for biomonitoring
in the Azores.
Authors:A.F.S. Garcia, A.M. Garcia, S.R. Vollrath, F. Schneck, C.F.M. Silva, Í.J. Marchetti, and J.P. Vieira
Food partitioning among coexisting species in different habitats remains an important research topic in trophic ecology. In this work, we combined carbon and nitrogen stable isotope ratios and stomach content analyses to investigate differences in diet and niche overlap of two congeneric juvenile mullet species (Mugil curema and Mugil liza) coexisting in a marine surf-zone and an estuarine zone in southern Brazil (29oS). These habitats have contrasting levels of food availability, especially in terms of prey diversity, with higher microalgae diversity in the estuary than in the marine surf-zone. In these contrasting conditions, we predicted that both mullet species will have (a) higher niche overlap and smaller niche breadth at the marine surf-zone due to the common exploration of highly abundant surf-zone diatoms and (b) lower niche overlap and higher niche breadth inside the estuary due to selective feeding on more diverse food resources. Isotope niche areas (measured as standard ellipse areas) were higher in the estuary (6.10 and 6.18) than in the marine surf-zone (3.68 and 3.37) for both M. curema and M. liza, respectively. We observed an overlap of 52% in isotopic niches of both species in the marine surf-zone and none in the estuary. We also found contrasting patterns in the diet composition between species according to the habitat. At the marine surfzone, diatoms of the classes Bacillariophyceae and Coscinodiscophyceae dominated (> 99%) the food content of both mullet species. In contrast, green algae, cyanobacteria, dinoflagellates and flagellates comprised the diet of both species in the estuary. These results could be explained by spatial differences in food availability (especially regarding diversity of microalgae) between both habitats. At the marine site, both species explored the most abundant microalgae available (mostly the surf-zone diatom Asterionellopsis cf. guyunusae and fragments of Coscinodiscus), whereas in the estuary both species shifted their diets to explore the greater diversity of microalgae resources. Overall, our findings revealed that niche partitioning theory could not fully predict changes in breadth and overlap of food niches of estuarine dependent fish species with complex life cycles encompassing marine to estuarine systems with contrasting food availabilities.
Authors:Eunice F. S. Vieira, Antonio R. Cestari, Wagner A. Carvalho, Cíntia dos S. Oliveira, and Renata A. Chagas
Fish scale of the species Leporinus elongatus was tested as an adsorbent for anionic Remazol dyes. Characterization has suggested that hydroxyl, phosphate, amides I, II, and III, and carbonate groups are the potential sites of adsorption. From solution calorimetry, values of thermal effects, Qint, and amount of dye that interacts, nint, were determined. The adsorption order observed was Yellow-dye/scale > Red-dye/scale > Blue-dye/scale. The Qint and nint data were successfully adjusted to the Langmuir isotherm model. The dyes removals by fish scale are exothermic processes (from −83 to −199 kJ mol−1) with negative entropies and are thermodynamically spontaneous. The thermodynamic results suggest that the interactions at scale/anionic dye interfaces occur mainly by surface reactions. It was finding that fish scale is a new and suitable sorbent material for recovery and biosorption/adsorption of anionic dyes from aqueous solutions.
Authors:F. Vieira, Soraia Souza, A. Oliveira, S. Lima, E. Longo, C. Paskocimas, L. Soledade, A. Souza, and Iêda Santos
In this study undoped and Cr, Sb or Mo doped TiO2 were synthesized by polymeric precursor method and characterized by X-ray diffraction, UV–VIS spectroscopy, infrared spectroscopy
and thermogravimetry (TG). The TG curves showed a continuous mass loss assigned to the hydroxyl elimination and Cr6+ reduction. Doped TiO2 samples showed a higher mass loss assigned to water and gas elimination at lower temperatures. In these doped materials a
decrease in the anatase–rutile phase transition temperature was observed. After calcination at 1,000 °C, rutile was obtained
as a single phase material without the presence of Cr6+.
Authors:C. Santos, B. Capistrano, F. Vieira, M. Santos, S. Lima, E. Longo, C. Paskocimas, A. Souza, L. Soledade, and I. Santos
In this work, spinels with the general formula Zn2−xCoxTiO4 were synthesized by the polymeric precursor method and thermally treated at 1,000 °C. The powder precursors were characterized
by TG/DTA. A decrease in the DTA peak temperature with the amount of zinc was observed. After the thermal treatment, the characterizations
were performed by XRD, IR, colorimetry and UV/VIS spectroscopy. The XRD patterns of all the samples showed the presence of
the spinel phase. Infrared spectroscopy showed the presence of ester complexes for Zn2TiO4 after thermal treatment at 500 °C, which disappeared after cobalt addition, indicating that organic material elimination