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Search Results: 1 - 10 of 718202 matches for " G. L. J. P. da;Rodrigues "
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Adsor??o de íons fosfato nos compósitos celulose/ZrO2.nH2O preparados pelos métodos da precipita??o convencional e em solu??o homogênea
Mulinari, D. R.;Silva, G. L. J. P. da;Rodrigues, L. A.;Silva, M. L. C. P. da;
Ceramica , 2007, DOI: 10.1590/S0366-69132007000400003
Abstract: this work describes the preparation and characterization of cellulose/hydrous zirconium oxide composites prepared by conventional precipitation (pc) and homogeneous solution (psh) from cellulose of the sugarcane bagasse and subsequent adsorption of phosphate ions. the composite obtained by the pc method was prepared using an ammonium solution as precipitating agent, whereas the composite obtained by the psh method was prepared using urea as precipitating agent. the adsorption of phosphate ions was carried out reacting a kh2po4 solution with ammonium molibdate under acid conditions to form an ammonium phosphomolybdic complex. the analyses to determine the concentration after adsorption were performed using uv-vis at 880 nm. the results were satisfactory showing that the cell/ zro2.nh2o composites obtained for both the methods presented good adsorption capacity.
Correlation between sodium and potassium excretion in 24- and 12-h urine samples
Mill, J.G.;Silva, A.B.T. da;Baldo, M.P.;Molina, M.C.B.;Rodrigues, S.L.;
Brazilian Journal of Medical and Biological Research , 2012, DOI: 10.1590/S0100-879X2012007500114
Abstract: low-sodium and high-potassium diets have been recommended as an adjunct to prevention and treatment of hypertension. analysis of these nutrients in 24-h urine has been considered the reference method to estimate daily intake of these minerals. however, 24-h urine collection is difficult in epidemiological studies, since urine must be collected and stored in job environments. therefore, strategies for shorter durations of urine collection at home have been proposed. we have previously reported that collecting urine during a 12-h period (overnight) is more feasible and that creatinine clearance correlated strongly with that detected in 24-h samples. in the present study, we collected urine for 24 h divided into two 12-h periods (from 7:00 am to 7:00 pm and from 7:00 pm to 7:00 am next day). a sample of 109 apparently healthy volunteers aged 30 to 74 years of both genders working in a university institution was investigated. subjects with previous myocardial infarction, stroke, renal insufficiency, and pregnant women were not included. significant (p < 0.001) spearman correlation coefficients (rs) were found between the total amount of sodium and potassium excreted in the urine collected at night and in the 24-h period (rs = 0.76 and 0.74, respectively). additionally, the 12-h sodium and potassium excretions (means ± sd, 95% confidence interval) corresponded to 47.3 ± 11.2%, 95%ci = 45.3-49.3, and 39.3 ± 4.6%, 95%ci = 37.3-41.3, respectively, of the 24-h excretion of these ions. therefore, these findings support the assumption that 12-h urine collected at night can be used as a reliable tool to estimate 24-h intake/excretion of sodium and potassium.
Charge and spin distributions in GaMnAs/GaAs Ferromagnetic Multilayers
S. C. P. Rodrigues,L. M. R. Scolfaro,J. R. Leite,I. C. da Cunha Lima,G. M. Sipahi,M. A. Boselli
Physics , 2004, DOI: 10.1103/PhysRevB.70.165308
Abstract: A self-consistent electronic structure calculation based on the Luttinger-Kohn model is performed on GaMnAs/GaAs multilayers. The Diluted Magnetic Semiconductor layers are assumed to be metallic and ferromagnetic. The high Mn concentration (considered as 5% in our calculation) makes it possible to assume the density of magnetic moments as a continuous distribution, when treating the magnetic interaction between holes and the localized moment on the Mn(++) sites. Our calculation shows the distribution of heavy holes and light holes in the structure. A strong spin-polarization is observed, and the charge is concentrated mostly on the GaMnAs layers, due to heavy and light holes with their total angular momentum aligned anti-parallel to the average magnetization. The charge and spin distributions are analyzed in terms of their dependence on the number of multilayers, the widths of the GaMnAs and GaAs layers, and the width of lateral GaAs layers at the borders of the structure.
Kepler rapidly rotating giant stars
A. D. Costa,B. L. Canto Martins,J. P. Bravo,F. Paz-Chinchón,M. L. das Chagas,I. C. Le?o,G. Pereira de Oliveira,R. Rodrigues da Silva,S. Roque,L. L. A. de Oliveira,D. Freire da Silva,J. R. De Medeiros
Physics , 2015, DOI: 10.1088/2041-8205/807/2/L21
Abstract: Rapidly rotating giant stars are relatively rare and may represent important stages of stellar evolution, resulting from stellar coalescence of close binary systems or accretion of sub-stellar companions by their hosting stars. In the present letter we report 17 giant stars observed in the scope of the Kepler space mission exhibiting rapid rotation behavior. For the first time the abnormal rotational behavior for this puzzling family of stars is revealed by direct measurements of rotation, namely from photometric rotation period, exhibiting very short rotation period with values ranging from 13 to 55 days. This finding points for remarkable surface rotation rates, up to 18 times the Sun rotation. These giants are combined with 6 other recently listed in the literature for mid-IR diagnostic based on WISE information, from which a trend for an infrared excess is revealed for at least a half of the stars, but at a level far lower than the dust excess emission shown by planet-bearing main-sequence stars.
In vitro schistosomicidal effects of the essential oil of Tagetes erecta
Tonuci, Ligia R. S.;Melo, Nathalya I. de;Dias, Herbert J.;Wakabayashi, Kamila A. L.;Aguiar, Gabriela P.;Aguiar, Daniela P.;Mantovani, André L. L.;Ramos, Rafael C.;Groppo, Milton;Rodrigues, Vanderlei;Veneziani, Rodrigo C. S.;Cunha, Wilson R.;Silva Filho, Ademar A. da;Magalh?es, Lizandra G.;Crotti, Ant?nio E. M.;
Revista Brasileira de Farmacognosia , 2012, DOI: 10.1590/S0102-695X2011005000202
Abstract: the in vitro schistosomicidal effects of the essential oil obtained from tagetes erecta l. asteraceae, leaves (te-eo) collected in brazil against schistosoma mansoni worms are reported in this paper. the oil caused a significant decrease in the motor activity at 50 μg/ml as minimal concentration after 24 h. this oil also caused death of all the parasites and the separation of coupled pairs into individual male and female at 100 μg/ml after 24 h. the viability of adult worm groups treated with the te-eo at 100 μg/ml was similar to that of groups treated with praziquantel (positive control). in addition, the oil promoted the inhibition of eggs development at all the tested concentrations. these data indicate that the te-eo could be considered as a promising source for the development of new schistosomicidal agents.
ZE3RA: The ZEPLIN-III Reduction and Analysis Package
F. Neves,D. Yu. Akimov,H. M. Araújo,E. J. Barnes,V. A. Belov,A. A. Burenkov,V. Chepel,A. Currie,L. DeViveiros,B. Edwards,C. Ghag,A. Hollingsworth,M. Horn,G. E. Kalmus,A. S. Kobyakin,A. G. Kovalenko,V. N. Lebedenko,A. Lindote,M. I. Lopes,R. Lüscher,P. Majewski,A. St J. Murphy,S. M. Paling,J. Pinto da Cunha,R. Preece,J. J. Quenby,L. Reichhart,S. Rodrigues,P. R. Scovell,C. Silva,V. N. Solovov,N. J. T. Smith,P. F. Smith,V. N. Stekhanov,T. J. Sumner,C. Thorne,R. J. Walker
Physics , 2011, DOI: 10.1088/1748-0221/6/11/P11004
Abstract: ZE3RA is the software package responsible for processing the raw data from the ZEPLIN-III dark matter experiment and its reduction into a set of parameters used in all subsequent analyses. The detector is a liquid xenon time projection chamber with scintillation and electroluminescence signals read out by an array of 31 photomultipliers. The dual range 62-channel data stream is optimised for the detection of scintillation pulses down to a single photoelectron and of ionisation signals as small as those produced by single electrons. We discuss in particular several strategies related to data filtering, pulse finding and pulse clustering which are tuned to recover the best electron/nuclear recoil discrimination near the detection threshold, where most dark matter elastic scattering signatures are expected. The software was designed assuming only minimal knowledge of the physics underlying the detection principle, allowing an unbiased analysis of the experimental results and easy extension to other detectors with similar requirements.
Measurement of electron neutrino quasielastic and quasielastic-like scattering on hydrocarbon at $\langle E_ν \rangle $ = 3.6 GeV
MINERvA Collaboration,J. Wolcott,O. Altinok,L. Bellantoni,A. Bercellie,M. Betancourt,A. Bodek,A. Bravar,H. Budd,M. F. Carneiro,J. Chvojka,H. da Motta,J. Devan,S. A. Dytman,G. A. Diaz,B. Eberly,J. Felix,L. Fields,R. Fine,R. Galindo,H. Gallagher,A. Ghosh,T. Golan,R. Gran,D. A. Harris,A. Higuera,M. Kiveni,J. Kleykamp,M. Kordosky,T. Le,E. Maher,S. Manly,W. A. Mann,C. M. Marshall,D. A. Martinez Caicedo,K. S. McFarland,C. L. McGivern,A. M. McGowan,B. Messerly,J. Miller,A. Mislivec,J. G. Morfin,J. Mousseau,T. Muhlbeier,D. Naples,J. K. Nelson,A. Norrick,J. Osta,V. Paolone,J. Park,C. E. Patrick,G. N. Perdue,L. Rakotondravohitra,R. D. Ransome,H. Ray,L. Ren,D. Rimal,P. A. Rodrigues,D. Ruterbories,H. Schellman,D. W. Schmitz,C. J. Solano Salinas,N. Tagg,B. G. Tice,E. Valencia,T. Walton,M. Wospakrik,G. Zavala,D. Zhang,B. P. Ziemer
Physics , 2015,
Abstract: The first direct measurement of electron-neutrino quasielastic and quasielastic-like scattering on hydrocarbon in the few-GeV region of incident neutrino energy has been carried out using the MINERvA detector in the NuMI beam at Fermilab. The flux-integrated differential cross sections in electron production angle, electron energy and $Q^{2}$ are presented. The ratio of the quasielastic, flux-integrated differential cross section in $Q^{2}$ for $\nu_{e}$ with that of similarly-selected $\nu_{\mu}$-induced events from the same exposure is used to probe assumptions that underpin conventional treatments of charged-current $\nu_{e}$ interactions used by long-baseline neutrino oscillation experiments. The data are found to be consistent with lepton universality and are well-described by the predictions of the neutrino event generator GENIE.
Residual nucleus excitation energy in (e, e'p): reaction
Likhachev, V. P.;Arruda-Neto, J. D. T.;Cruz, M.T.F. da;Dias, H.;Duarte, S.B.;Carvalho Jr, W.R.;Hussein, M.S.;Lima, A.C.S.;Macedo, L.F.R.;Mesa, J.;Pashchuk, S.A.;Rodrigues, T.E.;Silva, G.;Schelin, H.R.;Tavares, O.A.P.;
Brazilian Journal of Physics , 2004, DOI: 10.1590/S0103-97332004000500012
Abstract: the propagation of the struck proton through the nuclear medium is studied in the semi-classical multicolli-sional internuclear cascade approach. the probability of formation of various residual nucleus configurations and the corresponding excitation energies were obtained as a function of the energy w transferred to the proton by the knockout.
Caracteriza??o da argila bentonítica para utiliza??o na remo??o de chumbo de efluentes sintéticos
Rodrigues, M. G. F.;Silva, M. L. P.;Silva, M. G. C. da;
Ceramica , 2004, DOI: 10.1590/S0366-69132004000300004
Abstract: the main objective of this paper is to characterize the chocolate smectite clays of boa-vista, state of paraíba (brazil), in their natural form, and after chemical treatment for their application in the removal of pb2+ from synthetic effluents. the following methods were used: x-ray fluorescence, x-ray diffraction, scanning electron microscopy and energy dispersive x-ray spectroscopy. in is work the procedures for pb2+ removal from a synthetic inorganic effluent using a natural clay were established. to evaluate the influence of the main parameters, such as ph, clay treatment and granulometry, on pb2+ removal, factorial planning was used and the best results obtained were ph 4.5, granulometry in the range of 35 to 48 mesh and natural clay.
Numerical Calculation With Arbitrary Precision
B. O. Rodrigues,L. A. C. P. da Mota,L. G. S. Duarte
Computer Science , 2007, DOI: 10.1142/S0218301307009014
Abstract: The vast use of computers on scientific numerical computation makes the awareness of the limited precision that these machines are able to provide us an essential matter. A limited and insufficient precision allied to the truncation and rounding errors may induce the user to incorrect interpretation of his/hers answer. In this work, we have developed a computational package to minimize this kind of error by offering arbitrary precision numbers and calculation. This is very important in Physics where we can work with numbers too small and too big simultaneously.
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