Últimos itens adicionados do Acervo: Universidade Católica de Temuco

A Universidade Católica de Temuco é uma institução privada confessional do Chile, fundada pelo bispo Alejandro Menchaca Lira em 1959.

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‣ Synthesis of a new polypyridinic highly conjugated ligand with electron-acceptor properties

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
A new acceptor polypyridinic ligand functionalized with a quinone fragment is reported. The ligand, dipyrido[3,2-a:2′,3′-c]-benzo[3,4]-phenazine-11,16-quinone, Nqphen, was synthesized by condensation of 1,10-phenanthroline-5,6-dione and 2,3-diamino-1,4-naphthoquinone. The syntheses of two rhenium complexes with this ligand are also reported.

‣ Incremental unknowns and graph techniques with in-depth refinement

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
With in-depth refinement, the condition number of the incremental unknowns matrix associated to the Laplace operator is p(d)O(1/ H2)O( logdh 3) for the first order incremental unknowns, and q(d)O(1/H2) O((logdh)2) for the second order incremental unknowns, where d is the depth of the refinement, H is the mesh size of the coarsest grid, h is the mesh size of the finest grid, p(d) = d - 1/2 and q(d) = d - 1/2 1/12d(d2 - 1). Furthermore, if block diagonal (scaling) preconditioning is used, the condition number of the preconditioned incremental unknowns matrix associated to the Laplace operator is p(d)O((logdh)2) for the first order incremental unknowns, and q(d)O( logd h ) for the second order incremental unknowns. For comparison, the condition number of the nodal unknowns matrix associated to the Laplace operator is O(1/h2). Therefore, the incremental unknowns preconditioner is efficient with in-depth refinement, but its efficiency deteriorates at some rate as the depth of the refinement grows.

‣ Canine neosporosis: Detection of sera antibodies in rural and urban canine population of Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Neospora caninum es un protozoo parásito cuya infección se ha reportado en vacunos, caninos y otras especies en diversas partes del mundo. Los perros actúan como huéspedes definitivos e intermediario a la vez. En esta especie la enfermedad se caracteriza por paresia y/o parálisis de los miembros posteriores y puede ser fatal tanto en cachorros infectados transplacentariamente como en adultos. En Chile, no existe información sobre Neospora en caninos pero se ha demostrado la presencia de anticuerpos contra el protozoo en bovinos, por tal motivo se propuso la identificación de la infección mediante la detección de anticuerpos séricos contra N. caninum en perros. Se estudiaron 201 sueros caninos de diferentes edades, sexo, raza, ambiente ("rural" vs. "urbano") y tipo de alimentación ("carne cruda" vs. "no cruda") en una dilución 1:50 mediante la técnica de Inmuno Fluorescencia Indirecta (IFA). Del total de perros estudiados, el 18% (36/201) presentó anticuerpos contra N. caninum. Además se demostró asociación entre la cantidad de positivos y el ambiente y con el tipo de alimentación; no obstante, no hubo relación con el sexo, raza y edad. Los resultados indican que el pertenecer al ambiente rural y/o consumir carne cruda pueden ser importantes factores de riesgo dentro de la epidemiología de la infección por N.caninum. Complementariamente se procesaron dos sueros de zorros (Pseudolapex fulvipes) mediante la técnica del Aglutinación de taquizoitos de Neospora (NAT) que resultaron positivos hasta la máxima dilución analizada (1:320)...

‣ Chromosome counts in Philesia magellanica J.F. Gmel. (Liliales: Philesiaceae)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Mitotic chromosome counts documented here for Philesia magellanica J.F.Gmel. (Philesiaceae) showed a diploid number 2n = 30 (x = 15), which is different to the numbers reported previously for the species. The 2n number of P. magellanica is similar to that documented previously for Lapageria rosea, which indicate a constancy of chromosome number within the family.

‣ Pharmacokinetics of ampicillin in Alpacas (Lama pacos)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
La ampicilina es un antibiótico betalactámico de uso frecuente en medicina veterinaria. Dada la escasa o nula información existente en alpacas, en el presente estudio se plantea como objetivo describir el comportamiento farmacocinético en esta especie. Para ello se utilizaron 6 alpacas a las cuales se les administraron por las vías endovenosa e intramuscular, 15 mg/kg de ampicilina. Las concentraciones en suero fueron obtenidas por el método microbiológico, usando Bacillus subtilis ATCC 6633 como microorganismo patrón. Las concentraciones decayeron en forma biexponencial. Los parámetros obtenidos en suero para la vía endovenosa e intramuscular fueron respectivamente (media ± desviación estandar): t ½a = 0,14 ± 0,08 y 0,35 ± 0,12 horas; t½b = 0,60 ± 0,20 y 0,79 ± 0,52 horas; Vdss = 0,63 ± 0,05 y 0,80 ± 0,25 l/kg; Cltotal = 15,96 ± 3,00 y 15,79 ± 2,89 ml/min/kg; ABC = 16,43 ± 3,44 y 17,22 ± 2,20 m g/ml*h. Cuando se administró por la vía i.m., el valor de t½a fue de 0,05 ± 0,01 horas; Cmax = 18,38 ± 3,8 ug/ml y tmax = 0,16 ± 0,04 horas. La biodisponibilidad fue de 107 ± 20 %. No se encontraron diferencias estadísticamente significativas entre los parámetros obtenidos por las distintas vías de administración. La ampicilina demostró alcanzar concentraciones efectivas en suero que superan la concentración inhibitoria mínima (CIM) para la mayoría de los patógenos gram positivos de interés veterinario hasta 3...

‣ IAA oxidase activity on species of Nothofagus genus cuttings

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
There is variation in rooting capacity among the different species of Nothofagus. Lenga cuttings (N. pumilio) present an almost null answer to rooting, compared to raulí (N. alpina) and roble (N. obliqua). According to antecedents compiled in literature, the endogenous levels of indole acetic acid (IAA), hormone responsible for the formation of adventitious roots, vary depending on the levels of IAA oxidase activity. Based on these observations, the IAA oxidase activity was comparativily analyzed in cuttings from these three Nothofagus species. To quantify the enzymatic activity, a spectrophotometric test was carried out, measuring at 535 nm. The residual amount of IAA was determined by reference to a calibration curve. The enzymatic activity was expressed in IAA mM mg protein-1 hours-1. The results show that lenga presents a greater IAA oxidase enzymatic activity when compared to the other analyzed species (P< 0.05). These results would support at least partially the differences in the rootting capacity in Nothofagus species studys.; Entre las distintas especies de Nothofagus existe variación en la capacidad de enraizamiento. Las estacas de lenga (N. pumilio) presentan una respuesta casi nula al enraizamiento, comparada con raulí (N. alpina) y roble (N. obliqua). Según antecedentes recopilados en literatura...

‣ Determination of homogeneous environment units using spatial analysis and multivariate statistic

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The aim of the study was to define homogeneous environmental units, inside a land planning model. A multivariate analysis of a number of elements of the biophysical environment of the area and of its accessibility was carried out by preparing and processing digital maps. Sixteen homogeneous environmental units were determined. The criteria used in defining these units on the ground was firstly the geomorphology of the area; secondly the physical characteristics, using slope and aspect; and thirdly the hydrography, in terms of the presence and availability of water. It is concluded that the model used is appropriate for the zone under study, since it helps in delimiting the environmental units. Finally, multivariate techniques are recommended for the treatment of territorial variables.

‣ Site index curves for Nothofagus dombeyi in the pre-Andean mountains of the province of Cautin, IX Region, Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The purpose of this study was to develop polymorphic site index curves for the regeneration of coigüe (Nothofagus dombeyi) in the pre-Andean mountains of the IX Region of Chile. Three forest sites were defined a priori for this purpose, based on a spatial analysis of physiographical variables related with ecological requirements of the species: elevation, aspect and gradient. Subsequently, for the purpose of adjusting the age-height models, an analysis was carried out in 50 sample units, together with a dendrometric sampling of 150 felled dominant and co-dominant trees. The results allowed the determination of three forest sites, with indexes of 20, 18 and 16 meters for a key age of 40 years. Aspect and elevation were both significant variables affecting site index.; El objetivo de este estudio consistió en la construcción de curvas de índice de sitio para renovales de coigüe (Nothofagus dombeyi) en la precordillera andina de la IX Región, Chile. Para esto se definieron a priori tres sitios forestales, a partir del análisis espacial de las variables fisiográficas altitud, exposición y pendiente. Posteriormente, con el objeto de ajustar los modelos de altura-edad se realizó un muestreo en 50 unidades muestrales y un análisis de tallo con volteo de 150 árboles dominantes y codominantes. Los resultados permitieron determinar la existencia de tres sitios forestales con índices de 20...

‣ Modeling and simulation of a biofilter for treatment of gas contaminated with sulfur compounds

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
A mathematical model and the simulation of a biofilter for the treatment of gaseous effluents are presented. The mixture included sulfur compounds such as hydrogen sulfide, methyl mercaptan, dimethyl sulfide and dimethyl disulfide, all dissolved in air. The conditions under which restrictions on diffusion are of less importance than biodegradation, which is the ultimate limiting factor, were determined. The model was applied to the biofilm and the results were used to simulate the behavior of the bioreactor. The flows and maximum concentrations of contaminants in the mixture to be treated for a given size of bioreactor, were determined. Also, the concentration-related variations in the efficiency of the removal of contaminants under varying conditions of flow and concentration in the mixture, were established. It was found that biodegradation in the biofilm was the limiting factor for mixtures with concentrations of contaminants greater than 90 ppm.

‣ The lid-driven square cavity flow : From stationary to time periodic and chaotic

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Ranging from Re=100 to Re=20,000, several computational experiments are conducted, Re being the Reynolds number. The primary vortex stays put, and the longterm dynamic behavior of the small vortices determines the nature of the solutions. For low Reynolds numbers, the solution is stationary; for moderate Reynolds numbers, it is time periodic. For high Reynolds numbers, the solution is neither stationary nor time periodic: the solution becomes chaotic. Of the small vortices, the merging and the splitting, the appearance and the disappearance, and, sometime, the dragging away from one corner to another and the impeding of the merging - these mark the route to chaos. For high Reynolds numbers, over weak fundamental frequencies appears a very low frequency dominating the spectra - this very low frequency being weaker than clear-cut fundamental frequencies seems an indication that the global attractor has been attained. The global attractor seems reached for Reynolds numbers up to Re=15,000. This is the lid-driven square cavity flow; the motivations for studying this flow are recalled in the Introduction.

‣ Human exploitation of seabirds in coastal southern Chile during the mid-Holocene

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Se analizaron 738 restos óseos de aves, correspondientes a un mínimo de 71 individuos, encontrados en un asentamiento de cazadores-recolectores del Holoceno medio, 5.000 años AP, en la localidad costera de Chan Chan, sur de Chile. El campamento fue habitado durante al menos 500 años, tiempo durante el cual se ejerció una presión de caza persistente sobre los recursos marinos locales, particularmente las aves marinas. El taxón más numeroso (restos/ número de individuos) fue el lile Phalacrocorax gaimardi (551/44) que además fue la presa comestible más aprovechable. Albatros Thalassarche cf. melanophris. (103/12) y fardelas Puffinus cf. griseus (20/5) fueron presas secundarias. Los cormoranes fueron presumiblemente cazados en sus colonias reproductivas (las que aún existen en la zona) por lo que es probable que también se hayan consumido los huevos. Por sus hábitos pelágicos, los albatros pudieron haber sido cazados en el mar, aunque la tecnología necesaria para ello (botes, anzuelos) aún no ha sido demostrada en el registro arqueológico. El ensamble avifaunístico de la muestra no difiere cualitativamente del actual, lo que indica una estabilidad en la riqueza de especies desde el período considerado hasta el presente. La gran diversidad de recursos costeros de Chan Chan habría sido importante en la ocupación de estos sectores por grupos de cazadores-recolectores...

‣ Hantavirus risk maps for Conguillío National Park, southern Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The risk of infection with Hantavirus depends on factors that determine a probability of contagion with the reservoirs: (a) the vegetation structure and the land use as a primary scene, where specific factors such as composition, structure and density of the vegetation describe elements related to the habitat of the reservoirs, (b) The existence of populations of reservoir rodents, (c) Human establishments, such as availability and density of roads, inhabited areas or human presence (e.g., houses, warehouses). These three factors, brought together, provide the necessary facts to establish the risk. It is important to consider that these factors have a dynamics of seasonal change during the year and natural and man-made environmental modifications. In this way, we seek to understand the risk to which humans beings are submitted in the rural space. The spatial models correspond to representations of the reality observed in a certain area and determined to diverse geographical, topographic, biological, climatic factors, etc. The aim of this study was to establish potential sectors of risk to Hantavirus in a national park of the Region IX of Chile using thematic maps of environmental variables in a Geographical Information System to analyze aereal photograhs by means of photo interpretation...

‣ Effects of gas flow rate, inlet concentration and temperature on the biofiltration of toluene vapors

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
In this work the variation in the elimination capacity of a biofilter as a function of the gas flow and toluene concentration was studied. A bioreactor 0.75 m high×14.5 cm diameter was used, divided into three equal stages, using compost to support the microorganisms, and sea shells to control the pH. The biofiltration of toluene was evaluated for flows between 0.12 and 0.73 m3 h-1 in a concentration range of 1-3.2 g m-3. It was observed that on increasing the toluene inlet load by 90% (from 37 to 70 g m3 h-1), the conversion by the biofilter varied by only 5% (from 98% to 93%). The biofiltration system used achieved elimination capacities of up to 82 g m-3 h-1 for a toluene load of 100 g m-3 h-1.

‣ Glutathion peroxidase activity (GSH-Px) in grazing dairy cattle in the south of Chile (IXth Region) and their relation with selenium contents in the forage

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Con el objeto de determinar la actividad sanguínea de glutatión peroxidasa (GSH-Px; E.C. 1.11.1.9) en bovinos lecheros de la IX Región de la Araucanía (38º LS y 71º LO), Chile, y establecer su eventual asociación con el contenido de Se en el forraje, durante el otoño y la primavera de 1999 se tomaron muestras de forraje de las praderas y de sangre en grupos de vacas en inicio de lactancia y vaquillas en 12 predios lecheros. Se midió la concentración de Se en el forraje empleando la técnica de espectroscopía de plasma acoplado inductivamente con detector de masas (ICP-MS) y la actividad sanguínea de GSH-Px mediante una técnica cinética compuesta NADPH-dependiente. La concentración de Se del forraje fue 0.03±0.02 ppm, donde un 83% presentó valores deficitarios (<0,05 ppm). La actividad de GSH-Px fue 129±112 U/g Hb, encontrando en las vacas una mayor actividad que en las vaquillas (p<0.05), con valores similares en otoño y primavera (p>0.05). Se encontró un 20% de los grupos analizados con valores deficitarios (< 60 U/g Hb) para la actividad enzimática. Se observó una asociación entre la actividad sanguínea de GSH-Px en vaquillas con el contenido del mineral en el forraje (r=0.74; p<0.05). Los resultados permiten concluir que en la mayoría de los forrajes producidos por las praderas del área lechera de la IX Región de la Araucanía presentan bajas concentraciones de Se para ser empleados en la alimentación de bovinos de lechería y su consumo se asocia a una baja actividad sanguínea de GSH-Px que señala deficiencias metabólicas de Se en los animales...

‣ Skew-symmetric distributions generated by the distribution function of the normal distribution

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
In this paper we study a general family of skew-symmetric distributions which are generated by the cumulative distribution of the normal distribution. For some distributions, moments are computed which allows computing asymmetry and kurtosis coefficients. It is shown that the range for asymmetry and kurtosis parameters is wider than for the family of models introduced by Nadarajah and Kotz (2003). For the skew-t-normal model, we discuss approaches for obtaining maximum likelihood estimators and derive the Fisher information matrix, discussing some of its properties and special cases. We report results of an application to a real data set related to nickel concentration in soil samples.

‣ Physico-chemical quality of the waters in the Malleco National Park located in the IX region of Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
A study was done on the quality of the waters of the rivers Amargos and Niblinto and their effluents in the Malleco National Park-Chile. The water flows studied are of ritral type, have high slope, low water flow, high speed, low temperature and highly oxygenated waters. Six sampling points were established to perform the physico-chemical characterization. The sampling program, the analytical techniques for preservation and conservation of the samples were set according to the current legal standards. The results show that all the parameters considered are within reference values, concluding that the waters are of good quality.

‣ Karyological studies in Chilean species of Bomarea and Leontochir (Alstroemeriaceae)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Species from two genera belonging to the Alstroemeriaceae, Bomarea and Leontochir, were cytogenetically studied and compared to determine their detailed karyotypic composition. Bomarea is a polytypic genus represented by 100 species, with a distribution range from Mexico and Antilles (24°N) to Argentina (29°S) and Chile (17-40°S). In contrast Leontochir is a monotypic genus, endemic to the coastal area of the Atacama Desert in Chile (28°S). Bomarea salsilla, B. involucrosa, and Leontochir ovallei have a karyotype 2n = 18 with similar chromosome morphology. These data confirm the close relationship between both genera, suggested by earlier studies.

‣ Teaching and Learning Iterative Methods for Solving Linear Systems Using Symbolic and Numeric Software

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
An integral approach is presented to strengthen the teaching and learning processes in the environment of the undergraduate course Numerical Analysis (NA) for engineering, examining tha advantages of combining the symbolic and numeric paradigms. In particular, the methodology is illustrated with the iterative methods: Gauss-Seidel (GS) and Conjugated Gradient (CG), for the numeric solution of Linear Systems (LS). The computer tools MATLAB and MAPLE are used in a pedagogic model that requires the explicit definition of Prospective Learnings and Activities of Learning.

‣ Kinetics of cross-inhibited denitrification of a high load wastewater

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Batch denitrification of a synthetic saline medium at 37 °C, pH 7.5 was studied. A kinetic expression and an inhibition function which adequately expresses inhibition and cross-inhibition by nitrate and nitrite in denitratation and denitritation steps occurring in high organic and nitrate load wastewater treatment was determined. Denitratation and denitritation rates were measured independently. Monod- and Haldane-type kinetics were used for denitratation and denitritation, respectively. The maximum specific rate, kN O3 = 12.7 mg N O3 -N / g VSS h, and the saturation constant, KSN O3 = 0.47 mg N O3 -N / L were calculated for denitratation. The maximum specific rate, kN O2 = 13.8 mg N O2 -N / g VSS h, the saturation constant KSN O2 = 0.36 mg N O2 -N / L and the inhibition constant KI-N O2 = 906 mg N O2 -N / L were calculated for denitritation. Among other functional forms the Levenspiel inhibition model for denitratation and denitritation kinetics was proposed. The Levenspiel constants were SN O2 -M = 1149.4 mg N O2 -N / L, SN O3 -M = 34.7 mg N O3 -N / L, β1 = 1.578 and β2 = 1.005, respectively. The fitted experimental values show a good representation of the denitrification of effluents with high nitrogen load containing both nitrate and nitrite. Parametric sensitivity analysis show that inhibition functions (fi) and dimensionless constants (βi) greatly affect predicted nitrite and nitrate consumption rates.

‣ Convergence of a MFE-FV method for two phase flow with applications to heap leaching of copper ores

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
In this paper we describe error estimates for a finite element approximation to partial differential systems describing two-phase immiscible flows in porous media, with applications to heap leaching of copper ores. These approximations are based on mixed finite element (MFE) methods for the pressure and velocity and finite volume (FV) for the saturation. The fluids are considered incompressible. Numerical results for heap leaching simulation are presented.