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Search Results: 1 - 10 of 626838 matches for " Acu?a C. John Fabio "
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Influencia de la arborización en estructuras de Santa Fe de Bogotá
Acua C. John Fabio
Ingeniería e Investigación , 1999,
Abstract: Los árboles son vitales para cualquier ciudad, pues constituyen un referente fundamental para el adecuado uso de los sentidos debido a que comportan formas, olores, colores y sabores naturales en un medio donde el resto del paisaje es artificial. Contribuyen con la salud al purificar el aire; con la ecología y medio ambiente porque son anfitriones de muchas otras formas de vida, son fuente de belleza, recreación y armonía, dando además un sello de identidad a la urbe. Sin embargo, su implantación y manejo exige conocimientos y cuidados, para asegurar una armoniosa y perdurable integración con la ciudad.
DYNAMIC SIMULATION OF A FURNACE OF STEAM REFORMING OF NATURAL GAS
ACUA,A; FUENTES,C; SMITH,C. A;
CT&F - Ciencia, Tecnología y Futuro , 1999,
Abstract: steam reforming of natural gas is a very important industrial process in refineries and ammonia and methanol plants. hydrogen is produced by reforming methane with steam. this hydrogen is essential in the hydrotreating process in the refineries thus, it is important to supervise and control the performance of the hydrogen plant. mathematical models of refineries and chemical plants are used to simulate the behavior of the process units. however, the models especially of reactors like reformers, are not very reliable. this paper presents a dynamic model of a furnace reactor. the simulation results are validated with industrial data.
DYNAMIC SIMULATION OF A FURNACE OF STEAM REFORMING OF NATURAL GAS
A ACUA,C FUENTES,C. A SMITH
CT&F - Ciencia, Tecnología y Futuro , 1999,
Abstract: Steam reforming of natural gas is a very important industrial process in refineries and ammonia and methanol plants. Hydrogen is produced by reforming methane with steam. This hydrogen is essential in the hydrotreating process in the refineries thus, it is important to supervise and control the performance of the hydrogen plant. Mathematical models of refineries and chemical plants are used to simulate the behavior of the process units. However, the models especially of reactors like reformers, are not very reliable. This paper presents a dynamic model of a furnace reactor. The simulation results are validated with industrial data. El reformado de gas natural con vapor de agua es un proceso muy importante a nivel industrial en refinerías y plantas de amoníaco y metanol. El hidrógeno es producido principalmente por reformado de metano y es esencial en refinerías, en los procesos de hidrotratamiento, por esta razón es importante supervisar y controlar el desempe o de las unidades de hidrógeno. Actualmente en las refinerías y plantas químicas se utilizan modelos para simular el comportamiento de las unidades de proceso. Sin embargo, los modelos especialmente de reactores como reformadores, no son muy confiables. Este artículo presenta un modelo dinámico de un horno reactor de reformado, que considera las reacciones y los procesos de transferencia de masa y energía, que se llevan a cabo en este reactor. Los resultados obtenidos en la simulación son validados con datos a nivel industrial.
Antigenicity and Immunogenicity of Plasmodium vivax Merozoite Surface Protein-3
Amanda R. Bitencourt, Elaine C. Vicentin, Maria C. Jimenez, Ricardo Ricci, Juliana A. Leite, Fabio T. Costa, Luis C. Ferreira, Bruce Russell, Fran?ois Nosten, Laurent Rénia, Mary R. Galinski, John W. Barnwell, Mauricio M. Rodrigues, Irene S. Soares
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056061
Abstract: A recent clinical trial in African children demonstrated the potential utility of merozoite surface protein (MSP)-3 as a vaccine against Plasmodium falciparum malaria. The present study evaluated the use of Plasmodium vivax MSP-3 (PvMSP-3) as a target antigen in vaccine formulations against malaria caused by P. vivax. Recombinant proteins representing MSP-3α and MSP-3β of P. vivax were expressed as soluble histidine-tagged bacterial fusions. Antigenicity during natural infection was evaluated by detecting specific antibodies using sera from individuals living in endemic areas of Brazil. A large proportion of infected individuals presented IgG antibodies to PvMSP-3α (68.2%) and at least 1 recombinant protein representing PvMSP-3β (79.1%). In spite of the large responder frequency, reactivity to both antigens was significantly lower than was observed for the immunodominant epitope present on the 19-kDa C-terminal region of PvMSP-1. Immunogenicity of the recombinant proteins was studied in mice in the absence or presence of different adjuvant formulations. PvMSP-3β, but not PvMSP-3α, induced a TLR4-independent humoral immune response in the absence of any adjuvant formulation. The immunogenicity of the recombinant antigens were also tested in formulations containing different adjuvants (Alum, Salmonella enterica flagellin, CpG, Quil A,TiterMax? and incomplete Freunds adjuvant) and combinations of two adjuvants (Alum plus flagellin, and CpG plus flagellin). Recombinant PvMSP-3α and PvMSP-3β elicited higher antibody titers capable of recognizing P. vivax-infected erythrocytes harvested from malaria patients. Our results confirm that P. vivax MSP-3 antigens are immunogenic during natural infection, and the corresponding recombinant proteins may be useful in elucidating their vaccine potential.
Asymptotic expression for the fixation probability of a mutant in star graphs
Fabio A. C. C. Chalub
Quantitative Biology , 2014,
Abstract: We consider the Moran process in a graph called "star" and obtain the asymptotic expression for the fixation probability of a single mutant when the size of the graph is large. The expression obtained corrects previously known expression announced in reference [E Lieberman, C Hauert, and MA Nowak. Evolutionary dynamics on graphs. Nature, 433(7023):312-316, 2005] and further studied in [M. Broom and J. Rychtar. An analysis of the fixation probability of a mutant on special classes of non-directed graphs. Proc. R. Soc. A-Math. Phys. Eng. Sci., 464(2098):2609-2627, 2008]. We also show that the star graph is an accelerator of evolution, if the graph is large enough.
EVALUACIóN DEL CONTENIDO DE ALMIDON EN PAPAS (SOLANUM TUBEROSUM CV. DESIRéE), PRODUCIDAS EN FORMA ORGáNICA Y CONVENCIONAL, EN LA PROVINCIA DE CURICó, REGIóN DEL MAULE
Loyola L,Nelson; Oyarce C,Eduardo; Acua C,Carlos;
Idesia (Arica) , 2010, DOI: 10.4067/S0718-34292010000200005
Abstract: chemical composition of potato tubers (solanum tuberosum, sp. tuberosum) cv. desirée was evaluated after two production alternatives; conventional and organic, and the components were: dry matter content, starch, proteins, total and reducing sugars. a total randomized design was used and the values were measured by the anova with a 95% of probability. there were no significant differences among the parameters evaluated under the two cultivation alternatives. sensory evaluation with fried potato were also realized by using tubers from the two cultivation alternatives, conventional and organic, at 30 days and 75 days after harvest. thirteen trained panelist participated, who evaluated the following attributes; color, texture and flavor. according to the panelist there were no differences in relation to any kind of potato tubers, after fried, whatever the cultivation alternatives, in relation to the sensory attributes.
EVALUACIóN DEL CONTENIDO DE ALMIDON EN PAPAS (SOLANUM TUBEROSUM CV. DESIRéE), PRODUCIDAS EN FORMA ORGáNICA Y CONVENCIONAL, EN LA PROVINCIA DE CURICó, REGIóN DEL MAULE EVALUATION OF THE STARCH AMOUNT IN POTATOES (SOLANUM TUBEROSUM, SP. TUBEROSUM CV. DESIRéE), PRODUCED IN ORGANIC AND CONVENTIONAL WAYS IN THE PROVINCE OF CURICó, MAULE REGIóN
Nelson Loyola L,Eduardo Oyarce C,Carlos Acua C
IDESIA , 2010,
Abstract: Se evaluó la composición química de tubérculos de papas (Solanum tuberosum, sp Tuberosum) cv. Desirée, producidos bajo dos formas de cultivo convencional y orgánico; los componentes evaluados fueron: contenido de materia seca, almidón, proteínas, azúcares totales y azúcares reductores. Se usó un dise o completamente al azar y análisis de varianza con un 95% de exigencia para ver si existían diferencias estadísticas. El estudio concluyó en que no existieron diferencias significativas en los parámetros evaluados, bajo las dos formas de cultivo. También se realizaron evaluaciones sensoriales de papas fritas con tubérculos producidos en forma convencional y orgánica, a los 30 y 75 días de postcosecha, participando 13 panelistas entrenados, quienes evaluaron los atributos de: color, textura y sabor. Para expresar los resultados se utilizaron gráficos del tipo radial, no encontrándose diferencias marcadas a favor de un tipo de papas, luego de freírlas, independiente del tipo de cultivo realizado, de acuerdo a los atributos evaluados. Chemical composition of potato tubers (Solanum tuberosum, sp. tuberosum) cv. Desirée was evaluated after two production alternatives; conventional and organic, and the components were: dry matter content, starch, proteins, total and reducing sugars. A total randomized design was used and the values were measured by the anova with a 95% of probability. There were no significant differences among the parameters evaluated under the two cultivation alternatives. Sensory evaluation with fried potato were also realized by using tubers from the two cultivation alternatives, conventional and organic, at 30 days and 75 days after harvest. Thirteen trained panelist participated, who evaluated the following attributes; color, texture and flavor. According to the panelist there were no differences in relation to any kind of potato tubers, after fried, whatever the cultivation alternatives, in relation to the sensory attributes.
The HST Key Project on the Extragalactic Distance Scale XII. The Discovery of Cepheids and a New Distance to NGC 2541
Laura Ferrarese,Fabio Bresolin,Robert C. Kennicutt, Jr.,Abhijit Saha,Peter B. Stetson,Wendy L. Freedman,Jeremy R. Mould,Barry F. Madore,Shoko Sakai,Holland C. Ford,Brad K. Gibson,John A. Graham,Mingsheng Han,John G. Hoessel,John Huchra,Shaun M. Hughes,Garth D. Illingworth,Randy Phelps,Charles F. Prosser,N. A. Silbermann
Physics , 1998, DOI: 10.1086/306364
Abstract: We report the detection of Cepheids and a new distance to the spiral galaxy NGC 2541, based on data obtained with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope (HST). A total of 25 exposures (divided into 13 epochs) are obtained using the F555W filter (transformed to Johnson V), and nine exposures (divided into five epochs) using the F814W filter (transformed to Cousins I). Photometric reduction of the data is performed using two independent packages, DoPHOT and DAOPHOT II/ALLFRAME, which give very good agreement in the measured magnitudes. A total of 34 bona fide Cepheids, with periods ranging from 12 to over 60 days, are identified based on both sets of photometry. By fitting V and I period-luminosity relations, apparent distance moduli are derived assuming a Large Magellanic Cloud distance modulus and mean color excess of 18.50 +/- 0.10 mag and E(B-V) = 0.10 mag respectively. Adopting A(V)/E(V-I)=2.45, we obtain a true distance modulus to NGC 2541 of 30.47 +/- 0.11 (random) +/- 0.12 (systematic) mag (D = 12.4 +/- 0.6 (random) +/- 0.7 (systematic) Mpc), and a total (Galactic plus internal) mean color excess E(B-V) = 0.08 +/- 0.05 (internal error) mag.
The Hubble Space Telescope Extragalactic Distance Scale Key Project XXIII. The Discovery of Cepheids In NGC 3319
Shoko Sakai,Laura Ferrarese,Robert C. Kennicutt,John A. Graham,N. A. Silbermann,Jeremy R. Mould,Wendy L. Freedman,Fabio Bresolin,Holland C. Ford,Brad K. Gibson,Mingsheng Han,Paul Harding,John G. Hoessel,John P. Huchra,Shaun M. Hughes,Garth D. Illingworth,Daniel Kelson,Lucas Macri,Barry F. Madore,Randy L. Phelps,Abhijit Saha,Kim M. Sebo,Peter B. Stetson,Anne Turner
Physics , 1999, DOI: 10.1086/307776
Abstract: The distance to NGC 3319 has been determined from Cepheid variable stars as part of the Hubble Space Telescope Key Project on the Extragalactic Distance Scale. Thirteen and four epochs of observations, using filters F555W (V) and F814W (I) respectively, were made with the Wide Field Planetary Camera 2. Thirty-three Cepheid variables between periods of 8 and 47 days were discovered. Adopting a Large Magellanic Cloud distance modulus of 18.50 +- 0.10 mag and extinction of E(V-I)=0.13 mag, a true reddening-corrected distance modulus (based on an analysis employing the ALLFRAME software package) of 30.78 +- 0.14 (random) +- 0.10 (systematic) mag and the extinction of E(V-I) = 0.06 mag were determined for NGC 3319. This galaxy is the last galaxy observed for the HST H0 Key Project.
The HST Key Project on the Extragalactic Distance Scale. XXII. The Discovery of Cepheids in NGC 1326-A
Charles F. Prosser,Robert C. Kennicutt, Jr.,Fabio Bresolin,Abhijit Saha,Shoko Sakai,Wendy L. Freedman,Jeremy R. Mould,Laura Ferrarese,Holland C. Ford,Brad K. Gibson,John A. Graham,John G. Hoessel,John P. Huchra,Shaun M. Hughes,Garth D. Illingworth,Daniel D. Kelson,Lucas Macri,Barry F. Madore,Nancy A. Silbermann,Peter B. Stetson
Physics , 1999, DOI: 10.1086/307899
Abstract: We report on the detection of Cepheids and the first distance measurement to the spiral galaxy NGC 1326-A, a member of the Fornax cluster of galaxies. We have employed data obtained with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. Over a 49 day interval, a total of twelve V-band (F555W) and eight I-band (F814W) epochs of observation were obtained. Two photometric reduction packages, ALLFRAME and DoPHOT, have been employed to obtain photometry measures from the three Wide Field CCDs. Variability analysis yields a total of 17 Cepheids in common with both photometry datasets, with periods ranging between 10 and 50 days. Of these 14 Cepheids with high-quality lightcurves are used to fit the V and I period-luminosity relations and derive apparent distance moduli, assuming a Large Magellanic Cloud distance modulus (m-M) (LMC) = 18.50 +- 0.10 mag and color excess E(B-V) = 0.10 mag. Assuming A(V)/E(V-I) = 2.45, the DoPHOT data yield a true distance modulus to NGC 1326-A of (m-M)_0 = 31.36 +- 0.17 (random) +- 0.13 (systematic) mag, corresponding to a distance of 18.7 \pm 1.5 (random) \pm 1.2 (systematic) Mpc. The derived distance to NGC 1326-A is in good agreement with the distance derived previously to NGC 1365, another spiral galaxy member of the Fornax cluster. However the distances to both galaxies are significantly lower than to NGC 1425, a third Cepheid calibrator in the outer parts of the cluster.
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