Papers by Roseli Fernandes Gennari
Annals of Marine Science, 2020
The formation of the coastal plain of the Brazilian sea is mainly due to the fl uctuation of rela... more The formation of the coastal plain of the Brazilian sea is mainly due to the fl uctuation of relative sea level in the past. Armação dos Buzios or simply Buzios is a municipality in the microregion of lakes, in the state of Rio de Janeiro. In this region there is a lowland area about two meters above current sea level. This lowland area is also known as coastal plain of Una River. It is expected that during the Holocene period the sea level reached a maximum about 2.5 meters above the current level. During that time billions of mollusks lived and proliferated in the shallow waters around the coastal plain of the Una River. As they died their shells formed a layer in the soil including Malhada Marsh that belongs to the Una River plain. In this study, shells were collected from this region and dated using the techniques of Electronic Paramagnetic Resonance (EPR). Ages from 2480±130 to 4490±270 years were obtained. Radiocarbon dating were performed at the Beta Analytic Lab, USA for comparison with the EPR results. Shells ages obtained are compatible with geological data from the Holocene period relative to past sea level fl uctuations.
Water research, 2004
The high salinization in some reservoirs of the Contas river basin (Bahia-Brazil) has been errone... more The high salinization in some reservoirs of the Contas river basin (Bahia-Brazil) has been erroneously attributed only to concentration by evaporation. However, recent studies of this basin have shown that in period of intense rainfalls, occur an increase of the saline concentration in the flowing rivers of the reservoirs. The application of statistical methods (cluster and principal components analysis) have shown that this fact can be attributed to the discharge of saline waters from the small reservoirs of every drained area, provoked by inundation, is also an important factor in the salinization process. Thus the study of the geochemical variables: Na(+), K(+), Ca(2+), Mg(2+), Cl(-), SO(4)(2-) and CO(3)(2-), showed one group formed by Na(+) and Cl(-), attributed to the discharge of saline water provoked by inundation from a small reservoir, and a second group constituted by Ca(2+), Mg(2+), K(+) and SO(4)(2-), due to an increase provoked by the evaporation in the salinization pro...
Toxicological & Environmental Chemistry, 1996
... in air particulate samples collected in sampling sites in two différents districts (residenti... more ... in air particulate samples collected in sampling sites in two différents districts (residential, and residential commercial - industrial areas) representative of Salvador City. ... normalized value of the element i in the sample k; Q is the mean concentration of the element i; Cik is the ...
Proceedings of the SOUTHERN BRAZILIAN JOURNAL OF CHEMISTRY 2021 INTERNATIONAL VIRTUAL CONFERENCE, 2022
Ivory was commonly used in the manufacture of numerous objects. It refers to the tusk and teeth o... more Ivory was commonly used in the manufacture of numerous objects. It refers to the tusk and teeth of animals. Almost all ivory pieces, in the past, found on the market were authentic; however, nowadays, ivory extraction is an illegal practice. Thus, official government and animal protection entities have been fighting intensely against this criminal practice, but the production and sale continue. There are numerous difficulties in identifying the illegal extraction and use of ivory, and the correct characterization is certainly a significant challenge. A proper ivory characterization is an important tool in the fight against ivory extraction once it is possible to trace the piece to the animal and sometimes even to its origin. It is also useful for museums and art collectors to verify the authenticity of the piece. Ivory, also known as the inorganic gemstone, is composed of calcium phosphate, collagen, elastin, and lipids. Different tests can differentiate ivory from bones or celluloi...
Uranium mining and processing in Brazil occur in a northeastern area near to Caetité-BA. Several ... more Uranium mining and processing in Brazil occur in a northeastern area near to Caetité-BA. Several Non-Governmental Organizations claim that uranium mining in this region is a pollutant causing health risks to the local population,but those in charge of the complex extraction and production of"yellow cake" for generating fuel to the nuclear power plants reject these allegations. This study aimed at identifying potential problems caused by mining to the population of Caetité. In this, work,the concentrations of 238U, 232Th and 40K radioisotopes in the teeth of the Caetité population were determined by ICP-MS. Teeth are used as bioindicators of incorporated radionuclides. Cumulative radiation doses in the skeleton were also determined. The concentration values were below 0.008 ppm, and annual effective dose due to radioisotopes are below to the reference values. Therefore, it is not possible to state that the mining process in Caetité increases pollution or radiation exposure ...
Revista Memorare, 2018
As análises físico-químicas elucidam aspectos importantes no entendimento da complexidade de ocup... more As análises físico-químicas elucidam aspectos importantes no entendimento da complexidade de ocupações pré-coloniais. Objetivase analisar a pasta cerâmica de fragmentos de vasilhas provenientes de dois sítios arqueológicos localizados na Bacia Hidrográfica do Rio Forqueta/RS. Por meio da Espectrometria de Massas com Fonte de Plasma Indutivo (ICP-MS) foram obtidos os resultados da composição química das pastas. As análises multivariadas se deram através do programa Bioestat®. Percebe-se que entre a tipologia física das vasilhas, a diferença da composição química é sutil. É possível considerar que a matéria-prima para a confecção das peças de ambos os sítios provêm de locais com as mesmas características sedimentares.
Advances in Materials Science and Engineering, 2017
Two commercially available TlBr salts were used as the raw material for crystal growths to be use... more Two commercially available TlBr salts were used as the raw material for crystal growths to be used as radiation detectors. Previously, TlBr salts were purified once, twice, and three times by the repeated Bridgman method. The purification efficiency was evaluated by inductively coupled plasma mass spectroscopy (ICP-MS), after each purification process. A compartmental model was proposed to fit the impurity concentration as a function of the repetition number of the Bridgman growths, as well as determine the segregation coefficients of impurities in the crystals. The crystalline structure, the stoichiometry, and the surface morphology of the crystals were evaluated, systematically, for the crystals grown with different purification numbers. To evaluate the crystal as a radiation semiconductor detector, measurements of its resistivity and gamma-ray spectroscopy were carried out, using 241Am and 133Ba sources. A significant improvement of the radiation response was observed in function...
The Science of the total environment, 2017
Pollution in aquatic ecosystems due to negative human activities remains a problem in both freshw... more Pollution in aquatic ecosystems due to negative human activities remains a problem in both freshwater and marine environments and is an ongoing subject of research. Several studies have shown that some fish parasites can be used as a tool for biomonitoring because they demonstrate higher metal accumulation capacity compared to their host tissues. However, compared to acanthocephalans, information regarding the absorption mechanisms and accumulation rates in nematodes is relatively limited. Here, we evaluated the potential of larvae Contracaecum sp. (L3) as indicators of contamination by metals by analyzing thirteen element concentrations: magnesium (Mg), aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), barium (Ba), and lead (Pb) in the parasites and host Acestrorhynchus lacustris, using inductively coupled plasma mass spectrometry. Twelve of the thirteen analyzed elements were detected in at leas...
Anais da Academia Brasileira de Ciencias
A cylindrical fragment of stalagmite from Caverna do Diabo, State of São Paulo, Brazil, has been ... more A cylindrical fragment of stalagmite from Caverna do Diabo, State of São Paulo, Brazil, has been studied and dated by thermoluminescence and electron paramagnetic resonance techniques. The thermoluminescence glow curves of stalagmite samples and subsequently gamma irradiated, have shown rise of three peaks at 135, 180 and 265 °C. From electron paramagnetic resonance spectra of stalagmite was possible to clearly identify three paramagnetic centers in the g = 2.0 region: Centers I, II and III are due to , and , respectively. The additive method was applied to calculate the accumulated dose using thermoluminescence peak at 265 °C and the electron paramagnetic resonance signal at g = 1.9973 of CO- 2 radical. The ages of the different slices of stalagmite were determined from the Dac- values and Dan- value, obtaining an average of 86410 for central slice, 53421 for second slice, 31490 for third slice and 46390 years B.P. for the central region of upper end.
Revista do Museu de Arqueologia e Etnologia, 2006
Para os pesquisadores de arqueologia e geologia, dentre outras ciências, a informação sobre a ida... more Para os pesquisadores de arqueologia e geologia, dentre outras ciências, a informação sobre a idade dos materiais em estudo é importante. Há várias técnicas de datação, a começar do muito conhecido método de radiocarbono, apropriado para amostras que absorveram carbono no passado, outros se baseiam no decaimento radioativo de diferentes radioisótopos com meia vida apropriada, e aqueles que se baseiam na deposição parcial de energia de uma radiação ionizante, incidente sobre o material cuja idade se quer determinar. Fazem parte da última classe de métodos o de ressonância paramagnética eletrônica (EPR), de termoluminescência (TL) e o de luminescência oticamente estimulada (LOE ou OSL-optically stimulated luminescence), que são muitos usados pela sua facilidade de aplicação e alcance (Ka a Ma). Contudo, às vezes surgem resultados que têm causado dúvidas quanto à confiabilidade da técnica TL e OSL. O objetivo deste trabalho consiste em demonstrar que as medidas feitas em dois dos labor...
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Papers by Roseli Fernandes Gennari