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Search Results: 1 - 10 of 76715 matches for " Luiz Carlos Ruiz; "
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Data??o da fra??o humina da matéria organica do solo e sua compara??o com idades 14C de carv?es fósseis
Gouveia, Susy Eli Marques;Pessenda, Luiz Carlos Ruiz;Aravena, Ramon;
Química Nova , 1999, DOI: 10.1590/S0100-40421999000600007
Abstract: the radiocarbon dating of the soil organic matter (som) is a polemic subject, due mainly to the complexity of the formation of the soils and to the variable contamination from several sources. soil samples from 4 different brazilian localities were submitted to physical and chemical pre-treatment for the extraction of humin fraction, which is the most stable organic compound and theoretically the oldest and representative of the age of the som. the radiocarbon dating obtained from the total som and their humin fractions are compared to the 14c ages from buried charcoals at similar depths. the radiocarbon ages obtained from such charcoals are, in most of the cases, concordant within the experimental errors of those obtained on humin fractions, or are in average 10% higher, with one exception. thus, the ages on humin fractions could be assumed as the minimum ages for the associated soils, while the results obtained on total som, even at depths until 200 cm, exhibit pronounced contamination effect by modern carbon, rejuvenating their ages.
Data o da fra o humina da matéria organica do solo e sua compara o com idades 14C de carv es fósseis
Gouveia Susy Eli Marques,Pessenda Luiz Carlos Ruiz,Aravena Ramon
Química Nova , 1999,
Abstract: The radiocarbon dating of the soil organic matter (SOM) is a polemic subject, due mainly to the complexity of the formation of the soils and to the variable contamination from several sources. Soil samples from 4 different Brazilian localities were submitted to physical and chemical pre-treatment for the extraction of humin fraction, which is the most stable organic compound and theoretically the oldest and representative of the age of the SOM. The radiocarbon dating obtained from the total SOM and their humin fractions are compared to the 14C ages from buried charcoals at similar depths. The radiocarbon ages obtained from such charcoals are, in most of the cases, concordant within the experimental errors of those obtained on humin fractions, or are in average 10% higher, with one exception. Thus, the ages on humin fractions could be assumed as the minimum ages for the associated soils, while the results obtained on total SOM, even at depths until 200 cm, exhibit pronounced contamination effect by modern carbon, rejuvenating their ages.
Uma experiência em comunica??o e saúde
Matos, Marina Ruiz de;Meneguetti, Luiz Carlos;Gomes, Ana Luisa Zaniboni;
Interface - Comunica??o, Saúde, Educa??o , 2009, DOI: 10.1590/S1414-32832009000400016
Abstract: this paper reports on an experience developed in the municipality of guarulhos, under the sponsorship of the ministry of health, in which the aim was to involve radio broadcasters in the health education process. workshops on health subjects were organized with the participation of municipal healthcare service employees and community radio broadcasters with the same area of coverage, for reflection, discussion and elaboration of joint actions. the methodology developed brought together not only academic texts but also other types of language such as painting, music, radio serials, poetry, etc, to deal with these subjects. the final evaluation consisted of a questionnaire filled out by the participants. analysis on the responses indicated that this methodology was compatible with the aims of achieving involvement and developing partnerships between communicators, healthcare services and the community.
Pedological and isotopic relations of a highland tropical peatland, Mountain Range of the Espinha?o Meridional (Brazil)
Horák, Ingrid;Vidal-Torrado, Pablo;Silva, Alexandre Christófaro;Pessenda, Luiz Carlos Ruiz;
Revista Brasileira de Ciência do Solo , 2011, DOI: 10.1590/S0100-06832011000100004
Abstract: the evolution of organic matter sources in soil is related to climate and vegetation dynamics in the past recorded in paleoenvironmental quaternary deposits such as peatlands. for this reason, a histosol of the mineralotrophic peatland from the pau-de-fruta special protection area - spa, espinha?o meridional, state of minas gerais, was described and characterized to evidence the soil constituent materials and properties as related to changes in environmental conditions, supported by the isotopic and elementary characterization of soil c and n and 14c ages. samples were collected in a depression at 1,350 m asl, where histosols are possibly more developed due to the great thickness (505 cm). nowadays, the area is colonized by vegetation physiognomies of the cerrado biome, mainly rocky and wet fields (campo rupestre and campo úmido), aside from fragments of semidecidual seasonal forest, called cap?es forests. the results this study showed that early the genesis of the analyzed soil profile showed a high initial contribution of mostly herbaceous organic matter before 8,090 ± 30 years bp (14c age). in the lower-mid holocene, between 8,090 ± 30 years ap (14c age) to ± 4,100 years bp (interpolated age), the vegetation gradually became more woody, with forest expansion, possibly due to increased humidity, suggesting the existence of a more woody cerrado in the past than at present. drier climate conditions than the current were concluded ± 2,500 years bp (interpolated age) and that after 430 years bp (14c age) the forest gave way to grassland, predominantly. after the dry season, humidity increased to the current conditions. due to these climate fluctuations during the holocene, three decomposition stages of organic matter were observed in the histosols of this study, with prevalence of the most advanced (sapric), typical of a deposit in a highly advanced stage of pedogenetic evolution.
Surto de malária induzida entre usuários de drogas injetáveis
Barata,Luiz Carlos Barradas; Andriguetti,Maria Tereza M.; Matos,Marina Ruiz de;
Revista de Saúde Pública , 1993, DOI: 10.1590/S0034-89101993000100002
Abstract: five cases of malaria were detected among cocaine users by the local health service in bauru, a city with a population of 260,000, located 324 km from s. paulo, brazil, during the first three weeks of july 1990. autochthonous malaria had not occurred in bauru since 1978, and all the five cases denied having recently traveled to endemic areas. an extensive epidemiologic survey conducted from july 19 to september 13 revealed that the 5 cases were in fact part of a malaria outbreak among endovenous drug users. moreover, at least 114 other people, who had in the last three months shared syringes and needles with one or more proved cases, were also involved in the outbreak. one hundred and two people were identified and interviewed orally. the examination of thick smears made from samples collected from 99 of them confirmed 21 cases of vivax malaria. three people with negative blood smears had an indirect imunofluorescent assay positive to p. vivax antigen. although the index case could not be discovered, the investigation suggested that one or more people who had recently traveled to the amazon region might have introduced the disease. the control of the outbreak was achieved after offering treatment with chloroquine (10 tablets) to confirmed cases and contacts, followed by weekly suppresive chloroquine (2 tablets) until the last contact was detected. malaria examination of 91 blood samples also revealed a high prevalence of hepatitis b virus infection (40%) and hiv infection (58%) among those involved in the outbreak. the strategy used to identify the cases and the contacts and the difficulties overcome in carrying it through are described. it is also suggested that malaria might become an endemic disease among endovenous drug users in the state of s. paulo.
Soils Developed from Different Volcanic Rocks from the Fernando de Noronha Island: Rare-Earth Element Patterns and Isotopic Lead Composition
Sonia Maria Barros de Oliveira,Luiz Carlos Ruiz Pessenda,Marly Babinski,Simone Maria Costa Lima Gioia
Geologia USP : Série Científica , 2011,
Abstract: This study examines the infl uence of pedogenesis on the distribution of rare earth elements in soils derived fromdifferent rock types and formed under tropical humid climate, as well as the possible contribution of airborne Pb to thesesoils. We studied 5 soil profi les developed from different volcanic rocks cropping out in the Fernando de Noronha island.Results show that in the course of weathering, the soils were enriched in REE. The REE patterns of the soils are similarto those of the parent material, except for a slight HREE enrichment. Lead-isotope data indicate the presence of a nonradiogenicanthropogenic component in the upper horizons of the soil profi les.
Surto de malária induzida entre usuários de drogas injetáveis
Barata Luiz Carlos Barradas,Andriguetti Maria Tereza M.,Matos Marina Ruiz de
Revista de Saúde Pública , 1993,
Abstract: Em julho de 1990, foi registrado na cidade de Bauru, Estado de S o Paulo, Brasil, um surto de malária envolvendo usuários de cocaína injetável. Uma ampla investiga o epidemiológica, conduzida de 19 de julho a 13 de setembro, revelou que pelo menos 119 pessoas estavam envolvidas no surto, uma vez que haviam compartilhado seringas e agulhas com um ou mais casos confirmados nos 3 meses anteriores à ocorrência. Cento e duas dessas pessoas foram localizadas e entrevistadas, e destas, 99 foram submetidas a exame de gota espessa e 91 a exames sorológicos para malária. Foram confirmados por exame hemoscópico 21 casos de malária por P. vivax, e 3 outros tiveram exame sorológico positivo para P. vivax. O controle da transmiss o foi obtido fornecendo-se cloroquina aos envolvidos no surto, numa dose inicial de 10 comprimidos, seguida de doses supressivas semanais de 2 comprimidos até que fosse identificado o último comunicante. Amostras de soro coletadas na ocasi o revelaram, ao lado da malária, uma alta prevalência de infec es pelo HIV (58%) e pelo vírus da hepatite B (40%). Foram discutidas as dificuldades para o controle do surto e a possibilidade da malária vir a se tornar uma doen a endêmica entre usuários de drogas injetáveis, no Estado de S o Paulo.
Dinamica do ecótono floresta-campo no sul do estado do Amazonas no Holoceno, através de estudos isotópicos e fitossociológicos
Vidotto, Elaine;Pessenda, Luiz Carlos Ruiz;Ribeiro, Adauto de Souza;Freitas, Hermes Augusto de;Bendassolli, José Albertino;
Acta Amazonica , 2007, DOI: 10.1590/S0044-59672007000300010
Abstract: this paper presents a comparative study between organic soil horizons formed in depressions located at the forest/savanna boundary in the southern amazon basin. the influence of the paleovegetation dynamics, based on carbon isotope (12c, 13c and 14c) data of soil organic matter (som) and plants was evaluated, as well as the present vegetation dynamics, inferred from the modern vegetation structure, composition and phytosociology. the uppermost soil horizon in savanna showed higher total carbon content than in forest. 13c and 14c data from soil samples indicated a predominance of c3 plants in the early holocene. about 7000 to 3000 14c yr bp the influence of c4 plants increased, indicating savanna expansion probably related to a drier climate in the region. since approximately 3000 14c yr bp, the carbon isotope data suggest the expansion of forest probably due to a wetter climate. the presence of typical boundary plant species (sclerolobium paniculatum and himatanthus sucuuba) in the savanna also suggested present forest expansion.
Dispersantes químicos na análise granulométrica de latossolos
Mauri, Jocimar;Ruiz, Hugo Alberto;Fernandes, Raphael Bragan?a Alves;Ker, Jo?o Carlos;Rezende, Luiz Rogério Martins;
Revista Brasileira de Ciência do Solo , 2011, DOI: 10.1590/S0100-06832011000400021
Abstract: the complete sample dispersion and maintenance of stability in the dispersed phase are fundamental for a greater accuracy in soil texture analysis. for this purpose, na+ and li+ compounds were tested as alternative chemical dispersants, compared to a 10 mmol l-1 naoh solution, for the possibility of a more effective dispersion and to minimize the presence of pseudo components, basically pseudo-silt, in the particle size analysis of oxisols. eight samples of oxisols from the state of minas gerais, selected for their different parent materials and iron oxide contents were used. the treatments were arranged in a randomized block design, corresponding to a 2 x 8 x 7 factorial arrangement, with three replications. the factors consisted of eight oxisol samples, collected in the horizons a and b, and of seven dispersants. naoh was used as reference dispersant and the alternative dispersants tested were lioh, naclo, [naclo + naoh], [hcl + naoh], (napo3)n and [(napo3)n + naoh]. none of these identified the effectiveness of dispersants as well as naoh when using the highest clay proportion. the sequence of effectiveness was ranked as follows: naoh > [(napo3)n + naoh] > [hcl + naoh] > [naclo + naoh] > lioh > (napo3)n > naclo. among the alternative dispersants, the solution [(napo3)n + naoh] performed similarly to the reference dispersant, highlighting the importance of raising the ph values to near 12. the effectiveness of the other sodic solutions with high ph, [naclo + naoh] and [hcl + naoh], was reduced when raising the osmotic pressure of the solution, hampering soil dispersion. the performance of lioh was worse than of the reference. this response can be explained by the tendency of this alkali cation to form covalent bonds that block negative electric charges from the clay exchange complex, decreasing surface charge density. the dispersants (napo3)n and naclo were the least effective, due to the lower solution ph. it was concluded that naoh is most effective in dispersin
Biomembrana de látex: novo método para o revestimento da cavidade aberta nas timpanomastoidectomia
Sousa, Luiz Carlos Alves de;Piza, Marcelo Ribeiro de Toledo;Coutinho-Netto, Joaquim;Ruiz, Danielle Barbosa;Schmidt, Viviane Bom;
Revista Brasileira de Otorrinolaringologia , 2007, DOI: 10.1590/S0034-72992007000300007
Abstract: the new cavity created after an open cavity tympanomastoidectomy (octm) is filled with an antibiotic impregnated cotton pack (cotton tape, umbilical tape, gauze). the removal of this pack usually causes some bleeding and discomfort for the patient. we propose the use of a latex biomembrane to cover the cavity, which will act as an interface between the raw bone surface and the packing. study design: clinical prospective. aim: to study the performance of the latex biomembrane as an interface between the raw bone surface and the pack, and to analyze its role in cavity epithelization. material and methods: 64 ears of patients submitted to octm were studied. the biomembrane was used in the packing of 54 ears and in the 10 remaining ears the regular cotton tape packing was used. results: in the majority of the cases where the biomembrane was used the packing was removed much easier with no bleeding or pain for the patient and also showed an earlier cavity epithelization. conclusion: the use of the latex biomembrane has proven to be an effective method to cover the mastoid cavity facilitating epithelization and removal of mastoid cavity packing.
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