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Search Results: 1 - 10 of 542598 matches for " I. F. M. Albuquerque "
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New Upper Limit for the Branching Ratio of the Omega- to Xi- gamma Radiative Decay
I. F. Albuquerque
Physics , 1994, DOI: 10.1103/PhysRevD.50.R18
Abstract: We have searched for the rare hyperon radiative decay Omega- to Xi- gamma, using the Fermilab Proton Center 375 GeV/c charged hyperon beam. Our measurement of the Omega- beam fraction at 13.6 m from production is (4.8 +_ 0.4)10**(-5). No signal was found and we determine a new upper limit of (4.6 x 10**-4) at 90% CL for the Omega- to Xi- gamma branching ratio.
A Search for Light Super Symmetric Baryons
I. F. Albuquerque
Physics , 1996, DOI: 10.1103/PhysRevLett.78.3252
Abstract: We have searched for the production and decay of light super-symmetric baryons produced in 800 GeV/c proton copper interactions in a charged hyperon beam experiment. We observe no evidence for the decays R+(uud \g^~) -> S(uds \g^~) pi+ and X-(ssd \g^~) -> S(uds \g^~) pi- in the predicted parent mass and lifetime ranges of 1700-2500 Mev/c2 and 50-500 ps. Production upper limits for R+ at xF=0.47, Pt=1.4 GeV/c2 and X- at xF=0.48, Pt=0.65 GeV/c2 of less than 10^-3 of all charged secondary particles produced are obtained for all but the highest masses and shortest lifetimes predicted.
Processamento de ceramicas reticuladas a partir de matérias-primas naturais
Albuquerque, F. R.;Lima, S. J. G.;Paskocimas, C. A.;Longo, E.;Souza, A. G.;Santos, I. M. G.;
Ceramica , 2006, DOI: 10.1590/S0366-69132006000200011
Abstract: porous reticulated ceramics were obtained using a natural raw material (af) usually employed in the production of tiles and bricks, with kaolinite (ac) addition. the af raw material is constituted of quartz and feldspar. ceramic pieces were processed using the polymeric sponge impregnation. viscosities of the slurries with 70% of solids (wt./wt.) were optimized using sodium polyacrilate (paa-na) as deffloculant. suspensions without ac addition presented a viscosity of 600 mpa.s, decreasing to 300 mpa.s after addition of 20% (wt./wt.) ac. the optimized amount of paa-na was 2.0% (wt./wt.). tixotropy and pseudoplasty of the slurries made the impregnation process easier. polymeric sponges of 5, 10 and 40 pores/cm were used. ceramic pieces were sintered at 1100 and 1200 oc. x-ray diffractograms indicated the quartz dissolution at 1200 oc, leading to a material composed of mullite and vitreous phase. reticulated ceramics with a porosity of 10 pores/cm presented a rigid structure with mechanical strength higher than 1.70 mpa, with darcian permeability constant of about 3.58 x 10-9 (±10.0 %) m2.
Mass spectrometry of some arylidene thioxobenzyl or thioxobiphenyloxoethyl thiazolidinone compounds
V. L. M. Guarda,C. Bosso,S. L. Galdino,J. F. C. Albuquerque,M. C. A. Lima,J. B. P. Silva,L. F. C. Leite,I. R. Pitta
Spectroscopy: An International Journal , 2004, DOI: 10.1155/2004/175870
Abstract: This paper reports the results of a comparative study of the electron impact mass spectrometry data for a series of previously synthetized 5-arylidene-3-(4-chloro-benzyl)-4-thioxo-thiazolidin-2-one, and 5-arylidene-3-(2-biphenyl-4-yl-2-oxo-ethyl)-4-thioxo-thiazolidin-2-one derivatives. Theoretical calculations of molecular mechanics, MOPAC?AM1, were used to explain the fragmentations observed.
Planejamento experimental aplicado à otimiza??o de massas ceramicas contendo matérias-primas naturais
Albuquerque, F. R.;Santos, I. M. G.;Lima, S. J. G.;Cássia-Santos, M. R.;Soledade, L. E. B.;Souza, A. G.;Martinelli, A. E.;
Ceramica , 2007, DOI: 10.1590/S0366-69132007000300014
Abstract: the optimization of the composition is an important step in the development of ceramic products. in this work, experimental design was used in order to evaluate the relationship between properties and the composition of a system obtained from mixtures of natural raw materials extracted from "pegmatito do seridó", located near the border of the rn and pb states in brazil. the processing variables (temperature: 1100 and 1200o c and calcinations time: 0 and 2 h) and simplex centroid design were combined for the study of the ternary system. the smallest percentage of each component in the mixture was of 10% v/v. the rheological properties of aqueous suspensions obtained with 50% w/w were optimized with paa-na. the apparent porosity and apparent specific gravity were determined, besides retraction, after thermal treatment. the mineralogical composition of the ceramic pieces obtained at 1200 oc was basically mullite and quartz. the study allowed specifying the composition region which leads to the highest density after sintering, with a low number of samples.
Avalia??o antropométrica, fatores de risco para desnutri??o e medidas de apoio nutricional em crian?as internadas em hospitais de ensino no Brasil
Sarni, Roseli O. S.;Carvalho, Maria de Fátima C. C.;Monte, Cristina M. G. do;Albuquerque, Zuleica P.;Souza, Fabíola I. S.;
Jornal de Pediatria , 2009, DOI: 10.1590/S0021-75572009000300007
Abstract: objective: to evaluate risk factors for malnutrition, nutritional status and nutritional support provided in hospitalized children. methods: this longitudinal study prospectively followed, for 3 consecutive months, all children under 5 years of age (n = 907) hospitalized in general pediatric medical wards of 10 brazilian university-based hospitals. for data collection, a standard questionnaire was used and nutritional condition was evaluated at hospital admission and discharge: weight-for-height, weight-for-age and height-for-age z score. results: only 56.7% of the children had their nutritional classification documented in the medical record. at hospital admission, 16.3 and 30.0% of the children had moderate/severe malnutrition and low stature, respectively. risk of malnutrition was associated with low birth weight and younger age. a high percentage of nutritional deficiencies was observed in the children analyzed, although child's nutritional condition and the adoption of appropriate nutritional therapy were not documented in the medical records of the malnourished children. conclusion: these data underscore the importance of developing qualified hospital medical wards regarding diagnosis and therapeutic approach to malnutrition, based on the conduct guidelines already available in brazil.
Desempenho e propor??o sexual de tilápia vermelha sob à inclus?o de probiótico em água mesohalina
Marengoni,N.G.; Albuquerque,D.M.; Mota,F.L.S.; Passos Neto,O.P.; Silva Neto,A.A.; Silva,A.I.M.; Ogawa,M.;
Archivos de Zootecnia , 2010, DOI: 10.4321/S0004-05922010000300008
Abstract: the red tilapia adapts well to the high salinity and it is a great candidate for cultivation in mesohaline water. the probiotics are food supplements that can improve the productive performance in fish farming. this work was carried out to evaluate the productive performance and the sexual proportion of the red tilapia fingerlings (oreochromis sp., saint peter strain) under inclusion of increasing probiotic levels (0, 5, 10 and 15 g of probiotic/kg of commercial ration). as experimental units were used: water recycling systems - ras (experiment i) and cage - ter (experiment ii) using 0.5% and 1.0% mesohaline water respectively. a completely randomized design with four treatments and three repetitions was used. the productive performance and adjustment in the ration supply were verified at fortnighty biometries with duration of 42 and 70 days for ras and ter, respectively. the weight, weight gain, biomass, biomass gain, alimentary conversion, the mean daily weight gain, specific growth, condition factor and survival were not influenced by the inclusion of probiotic (p>0.05) in the two experimental units. the sexual proportion of the fingerlings in the 0.5% and 1.0% salinity were not influenced (p>0.05) for the inclusion levels of probiotic. at the end of the experiments, both body weight, and animal total length increased following a geometric model. it can be concluded that levels of commercial probiotic doesn't contribute satisfactorily to improve the performance of red tilapia reared in a recycling system (aquarium or cage) in mesohaline water.
Influence of eNOS gene polymorphism on cardiometabolic parameters in response to physical training in postmenopausal women
Esposti, R.D.;Sponton, C.H.G.;Malagrino, P.A.;Carvalho, F.C.;Peres, E.;Puga, G.M.;Novais, I.P.;Albuquerque, D.M.;Rodovalho, C.;Bacci, M.;Zanesco, A.;
Brazilian Journal of Medical and Biological Research , 2011, DOI: 10.1590/S0100-879X2011007500106
Abstract: the health-promoting effects of exercise training (et) are related to nitric oxide (no) production and/or its bioavailability. the objective of this study was to determine whether single nucleotide polymorphism of the endothelial no synthase (enos) gene at positions -786t>c, g894t (glu298asp) and at the variable number of tandem repeat (vntr) intron 4b/a would interfere with the cardiometabolic responses of postmenopausal women submitted to physical training. forty-nine postmenopausal women were trained in sessions of 30-40 min, 3 days a week for 8 weeks. genotypes, oxidative stress status and cardiometabolic parameters were then evaluated in a double-blind design. both systolic and diastolic blood pressure values were significantly reduced after et, which was genotype-independent. however, women without enos gene polymorphism at position -786t>c (tt genotype) and intron 4b/a (bb genotype) presented a better reduction of total cholesterol levels (-786t>c: before = 213 ± 12.1, after = 159.8 ± 14.4, δ = -24.9% and intron 4b/a: before = 211.8 ± 7.4, after = 180.12 ± 6.4 mg/dl, δ = -15%), and ldl cholesterol (-786t>c: before = 146.1 ± 13.3, after = 82.8 ± 9.2, δ = -43.3% and intron 4b/a: before = 143.2 ± 8, after = 102.7 ± 5.8 mg/dl, δ = -28.3%) in response to et compared to those who carried the mutant allele. superoxide dismutase activity was significantly increased in trained women whereas no changes were observed in malondialdehyde levels. women without enos gene polymorphism at position -786t>c and intron 4b/a showed a greater reduction of plasma cholesterol levels in response to et. furthermore, no genotype influence was observed on arterial blood pressure or oxidative stress status in this population.
GZK cutoff distortion due to the energy error distribution shape
Ivone F. M. Albuquerque,George F. Smoot
Physics , 2005, DOI: 10.1016/j.astropartphys.2006.03.010
Abstract: The observed energy spectrum of ultra high energy cosmic rays (UHECR) is distorted by errors in the energy reconstruction. Here we show that if the shape of the error distribution is lognormal, the high end of the cosmic ray spectrum will be distorted. This is distinct and potentially more significant than the effect of the magnitude of the error in the energy. We estimate the UHECR spectrum at the Earth assuming it is originated from a cosmological flux. We then convolute this flux assuming a lognormal error in the energy. We show that if the standard deviation of the lognormal error distribution is equal or larger than 0.25, both the shape and the normalization of the measured energy spectra will be modified significantly. As a consequence the GZK cutoff might be sufficiently smeared and as not to be seen. This result is independent of the power law of the cosmological flux. As a conclusion we show that in order to establish the presence or not of the GZK feature, not only more data is needed but also that the shape of the energy error distribution has to be known well.
Measuring Atmospheric Neutrino Oscillations with Neutrino Telescopes
Ivone F. M. Albuquerque,George F. Smoot
Physics , 2001, DOI: 10.1103/PhysRevD.64.053008
Abstract: Neutrino telescopes with large detection volumes can demonstrate that the current indications of neutrino oscillation are correct or if a better description can be achieved with non-standard alternatives. Observations of contained muons produced by atmospheric neutrinos can better constrain the allowed region for oscillations or determine the relevant parameters of non-standard models. We analyze the possibility of neutrino telescopes measuring atmospheric neutrino oscillations. We suggest adjustments to improve this potential. An addition of four densely-instrumented strings to the AMANDA II detector makes observations feasible. Such a configuration is competitive with current and proposed experiments.
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