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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‣ Una mirada al modo de vida canoero del mar interior desde piedra azul

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Se presentan los primeros resultados obtenidos en la investigación del sitio arqueológico 10 PM 014 "Conchal Piedra Azul", campamento base de poblaciones canoeras, el cual muestra un depósito formado por una sucesión de ocupaciones superpuestas, que refieren a un modo de vida cazador-pescador-recolector de gran persistencia a través del tiempo.; The first results obtained from archaeological excavation at 10 PM 014 site "Conchal Piedra Azul" are presented. This is a base camp of canoeists prehistoric populations that consist of a shell midden deposit, formed by superimposed occupations. The cultural material shows a hunting-gathering & fishing way of life (ca. 5.000 cal. BP.- to late prehistoric time).

‣ Presencia de anticuerpos sericos contra Neospora caninum en equinos en Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Neospora sp. es un parásito protozoario causante de abortos y/o enfermedad del Sistema Nervioso Central (SNC) en caninos, bovinos, ciervos, caprinos, ovinos, equinos y otros. En equinos, se lo ha involucrado como causa de aborto, mortalidad neonatal y enfermedades del SNC y viscerales. La especie que infecta a los equinos es distinta a Neospora caninum y se denomina Neospora hughesi. En Chile no existe evidencia de infección en equinos, sin embargo, la enfermedad ha sido informada en bovinos y caninos, por lo que el objetivo de este trabajo fue buscar anticuerpos contra la enfermedad en sueros equinos . Para ello se tomaron muestras de sangre a 145 equinos (87 de la IX Región y 58 de la VIII Región de Chile). Los sueros fueron analizados mediante Test de Aglutinación para Neospora (NAT). Cada suero se diluyó en 1:40 en solución salina tamponada (PBS pH 7.2) conteniendo 2- mercaptoetanol y fueron analizados en 1:40 y 1:80. Los sueros positivos a 1:80 fueron examinados a 1:160 y 1:320. Anticuerpos contra N.caninum (≥ 1:40) se encontraron en 32% (47/145) de los equinos estudiados. Debido a que N.caninum y N.hughesi dan reacción cruzada, ambos o uno de ellos podrían ser los responsables de la seropositividad. Estos resultados indican que equinos provenientes de la VIII y IX regiones de Chile son reaccionantes a la infección de Neospora...

‣ Salinity level and occurrence of centropagid copepods (Crustacea, Copepoda, Calanoida) in shallow lakes in Andes Mountains and Patagonian plains, Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
In Andes Mountains (14-27°S) and Patagonian plains (45-53°S) in Chile, there are numerous shallow saline and sub-saline lakes. These water bodies have important temporal and spatial variation of their salinity caused by mineral composition of their watershed or exposition to arid weather. In this study we compared the salinity level and the occurrence of centropagid copepods (Crustacea, Copepoda, Calanoida) in water bodies of both regions. In the Andes Mts the calanoids inhabit water bodies of salinity lower than 90 g l -1, and the representative species was Boeckella poopoensis (Marsh 1906), that occurs between 5.0 to 90.0 g l-1. In Patagonian plains, the copepods occur at salinity level between 0.1 to 16.0 g l-1, and within these values most frequent are B. popei (Mrázek 1901) and Parabroteas sarsi (Mrázek 1901). Both species can coexist with other calanoid species.

‣ Ecological restoration of sacred menokos from thee perspective (Chile) Mapuche

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português

‣ C-banding pattern in the geophytic Leontochir ovallei (Alstroemeriaceae)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The monotypic genus Leontochir Phil. (Alstroemeriaceae Dumortier), represented by Leontochir ovallei, is endemic to Chile, and its geographical distribution is restricted to the coastal zone of the Atacama Desert (28°S). In previous cytogenetic studies on L. ovallei a diploid karyotype 2n = 2x = 18 was described. In this work a first analysis of the C-banding pattern of L. ovallei is presented. L. ovallei showed large regions of constitutive heterochromatin within the karyotype, with C-bands on all chromosome pairs except 9. The relative length of the C-bands was 20.0% of the total haploid set length. The presence of large regions of constitutive heterochromatin on the chromosomes was concurrent with the presence of many conspicuous and large chromocenters in the interphase nuclei. According to these results, L. ovallei shows the largest value of relative C-band length so far described within the Alstroemeriaceae. These cytogenetic results on L. ovallei increase the available data on C-banding patterns in Alstroemeriaceae with an additional genus.

‣ Karyotype and C-bands in the annual inca lily Alstroemeria graminea

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Alstroemeria graminea Phil. (Taltalia graminea according to BAYER 1998) is the only annual species described within the genus Alstroemeria L. and its cytogenetic relationship with the perennial species have not been described. In this work, an analysis of the karyotype and the C-banding pattern of Alstroemeria graminea are reported. A. graminea, with an asymmetric karyotype 2n = 2x = 16, shows similar chromosome morphology with respect to the perennial Alstroemeria species previously analysed. However, some differences in relative length and position of the C-bands were observed in A. graminea. These differences were the presence of a centromeric band and an interstitial band in the short arm of pair 1 and pericentromeric bands in the long arms of pairs 3 and 7, which have not been observed in the other species. The cytogenetic data of the present study on A. graminea are concurrent with other species within the genus Alstroemeria, and do not justify the separation of this species from the genus Alstroemeria and its inclusion in the new monotypic genus Taltalia.

‣ Permeability-porosity relationship from a geometrical model of shrinking and lattice Boltzmann and Monte Carlo simulations of flow in two-dimensional pore networks

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
For a broad range of applications, the most important transport property of porous media is permeability. Here we calculate the permeability of pore network approximations of porous media as simple diagenetic or shrinking processes reduces their pore spaces. We use a simple random bond-shrinkage mechanism by which porosity is decreased; a tube is selected at random and its radius is reduced by a fixed factor, the process is repeated until porosity is reduced either to zero or a preset value. For flow simulations at selected porosity levels, we use precise Monte Carlo calculations and the lattice Boltzmann method with a 9-speed model on two-dimensional square lattices. Calculations show a simple power-law behavior, k ∝ φm, where k is the permeability and φ the porosity. The value of m relates strongly to the shrinking process and extension, and hence to the skewness of the pore size distribution, which varies with shrinking, and weakly to pore sizes and shapes. Smooth shrinking produces pore space microstructures resembling the starting primitive material; one value of m suffices to describe k versus φ for any value of porosity. Severe shrinking however produces pore space microstructures that apparently forget their origin; the k-φ curve is only piecewise continuous...

‣ Survival of two species of crustacean zooplankton under two chlorophyll concentrations and protection from or exposure to natural ultraviolet radiation

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The current, growing increase in penetration of ultraviolet (UV) radiation that has been reported over southern South America, would allegedly alter lacustrine ecosystems by bringing about photoprotective responses in biotic elements. The lacustrine zooplankton in the area is characterized by a predominance of calanoid copepods, mainly Boeckella spp., over cladocerans of the genus Daphnia, because the first group presumably has a higher tolerance towards exposure to ultraviolet radiation. An experiment was conducted involving exposure of two species of crustacean zooplankton to natural ultraviolet radiation, and providing protection from it by using two levels of chlorophyll a concentration. This study involved the non-pigmented species, Boeckella gracilipes (Daday, 1902) and Daphnia pulex (De Geer, 1778). The results showed that D. pulex exhibited a low mortality at high chlorophyll a levels, and concurrent protection against UV radiation. In contrast, B. gracilipes showed a significant, low mortality under exposure to UV radiation. © Koninklijke Brill NV, 2005.

‣ Flow through porous media with applications to heap leaching of copper ores

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The classical equations of two-phase flow in a porous media are solved together with two transport equations representing the leaching process. For the two-phase flow we use the pressure-saturation formulation, where the principal variables are the total pressure, the total flux and the saturation of the liquid phase. For the transport equations the variables of interest are the sulfuric acid and the copper concentration. The numerical method combines a mixed finite element method with a finite volume method. The first one is used to approximate the total pressure and flux, while the second is used to calculate the saturation and both concentrations. The advantage of this approach is its capacity to completely characterize the dynamics of the liquid and gaseous phase, and treat with the same model acid and bio-leaching processes. Several examples show the application of the method.

‣ In vitro and in vivo maturation of llama oocytes

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Cumulus-oocyte complexes (COC) were collected from abbatoir-derived llama ovaries and cultured in vitro for 28, 30, or 36 h at 39°C in 5% CO 2 to determine the time required for maturation. The majority of COC (n = 298, 87%) were classified as categories 1 and 2 (COC with ≥5 layers or 2-4 compact layers of cumulus cells, respectively) and homogeneous ooplasm, and the proportion that underwent nuclear maturation (MII) was 78, 81 and 80%, after 28, 30 and 36 h, respectively (P = 0.65). To compare the effectiveness of FSH versus eCG for inducing in vivo maturation, in experiment 2, llamas (n = 20 per group) were treated with: (1) 25 mg FSH, twice-daily for 4 day, plus 5 mg armour of LH at the end of FSH treatment; or (2) 1000 IU of eCG, plus 5 mg armour of LH 4 day after eCG treatment. The FSH- and eCG-treated groups did not differ (P = 0.85) with respect to the number of follicles ≥6 mm at the time of COC collection (17.9 ± 2.2 versus 17.7 ± 2.2), the number of COC collected (10.7 ± 2.1 versus 11.2 ± 2.3 per llama), or the collection rate per follicle aspirated (71 versus 74%). As well, no difference (P = 0.49) was detected between the FSH and eCG groups in the number of expanded COC collected (8.3 ± 2.1 versus 10.6 ± 2.2) or the number of COC at the MII stage (6.9 ± 1.8 versus 8.9 ± 1.9). In conclusion...

‣ Hexenuronic acid removal from unbleached kraft eucalyptus pulp by peroxymonosulfuric acid

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The use of peroxymonosulphuric (Ps) acid to remove hexenuronic acid (HexA) present in unbleached eucalyptus kraft pulps was evaluated here. HexA is formed during pulping and is held responsible for reagent consumption during bleaching. Laboratory experiments, using oxygen predelignified eucalyptus kraft pulps (kappa number around 9), treated at 20-110°C and 0.2-1.0%Ps, were conducted here, Experimental results show that Ps effectively removed both HexA and lignin, even under mild conditions. Selectivity towards HexA increased at higher temperature and lower Ps loads. However, at lower temperatures and higher Ps concentrations, cellulose was also attacked. As a result of Ps pre-treatment, ClO2 savings in pulp bleaching in the range 40-79% were determined here. Moreover, all Ps pretreated pulps yielded higher brightness than untreated pulps. Furthermore, lower AOX emissions occurred as a result of lower ClO 2 loads. However, moderate Ps pre-treatment conditions were necessary to obtain a bleached pulp with acceptable mechanical properties. Results reported here show that HexA removal by Ps offers an interesting option for industrial implementation, both from an economic and environmental point of view.

‣ Survival of pigmented freshwater zooplankton, exposed to artificial ultraviolet radiation and two levels of dissolved organic carbon

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The increase in penetration of ultraviolet radiation has been reported currently over southern South America. It would affect the photoprotective responses in biotic elements of freshwater ecosystems. An experiment was designed using pigmented adult individuals of the species Daphnia dadayana (Paggi 1999), Boeckella antiqua (Menu-Marque & Balseiro 2000), and Parabroteas sarsi (Mrázek 1901), characteristic for shallow fishless ponds from South American plains (located between 41 and 53°S latitude). The artificial ultraviolet radiation was involved in the experiment, with two levels of dissolved organic carbon (DOC), which would exert a protective effect against ultraviolet radiation. The results of this experiment showed that under conditions of low DOC concentrations, D. dadayana recorded a higher mortality, while under low DOC concentrations, B. antiqua and P. sarsi were not affected by ultraviolet radiation. Daphnids would be less tolerant to the exposure to ultraviolet radiation than pigmented calanoid copepods.

‣ Relocation of the freshwater mussel Diplodon chilensis (Hyriidae) as a strategy for its conservation and management

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português

‣ Effect of grazing pasture with a low selenium content on the concentrations of triiodothyronine and thyroxine in serum, and GSH-Px activity in erythrocytes in cows in Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
AIM: To determine the effect of grazing pasture that had a low selenium (Se) concentration on serum concentrations of triiodothyronine (T3) and thyroxine (T4), and erythrocyte glutathione peroxidase (GSH-Px) activity in dairy cows. METHODS: Forty pregnant Friesian cows were grazed on pasture that contained 0.03-0.04 ppm Se on a dry matter (DM) basis. Two months before parturition, 20 cows were randomly selected and treated with 1 mg Se/kg bodyweight subcutaneously, as barium selenate (Group Se-S). The other group (Se-D) was not supplemented. Blood samples were taken before supplementation (-60 days) and 30, 60, 90, 180 and 270 days after parturition, for determination of concentrations of T3 and T4 in serum, and GSH-Px activity in erythrocytes. RESULTS: Erythrocyte GSH-Px activity in the Se-D group was <60 U/g haemoglobin (Hb) throughout the experiment. Supplementation increased (p<0.05) activities to >130 U/g Hb throughout lactation. Mean serum concentrations of T4 in Se-D and Se-S cows increased from 23.7 (SEM 0.7) and 23.4 (SEM 0.8) nmol/L, respectively, in the prepartum period to 69.6 (SEM 0.1) and 67.6 (SEM 0.2) nmol/L, respectively, at 180 days of lactation (p<0.01), and no effect of Se supplementation was evident. Serum concentrations of T3 in Se-D cows decreased (p<0.05) from 1.6 (SEM 0.1) nmol/L prepartum to 1.0 (SEM 0.2) nmol/L at the beginning of lactation...

‣ Synthesis and characterization of polypiridine-based rhenium(I) complexes with pyrazino[2,3-f][1,10]phenanthroline

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
A series of tricarbonyl rhenium(I) complexes of the type fac-[Re 1(CO)3(Ppl)(L)]0/+, where ppl is pyrazino[2,3-f][1,10]phenanthroline, and where L is Cl-, TIO -, 4-(tert-butyl)pyridine (tBu-py), 4-methoxypyridine (MeO-py), 4,4′-bipyridyl (bpy), or 10-(picolin-4-yl)phenothiazine (pptz), were synthesized and fully characterized. In all complexes, an increment in the electron-acceptor properties of ppl compared to the free ligand was observed. This effect was more significant for pyridine-type ligands, especially for pptz, compared to Cl- or TfO-. The properties of fac-[Re(CO)3(ppl)(pptz)]PF6 were compared with those of the analogous compound fac-[Re(CO)3(dppz)(pptz)]PF6, where dppz is dipyrido(3,2-a: 2′,3′-c)phenazine, the goal being to generate long-lived excited charge-transfer (CT) states. In this respect, fac-[Re(CO)3(ppl)(pptz)]PF6 seems to be a promising candidate.

‣ Influence of ligand structure and molecular geometry on the properties of d6 polypyridinic transition metal complexes

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Different strategies to improve the excited state properties of polypyridinic complexes by varying ligand structure and molecular geometry are described. Bidentate and tetradentate ligands based on fragments as dipyrido[3,2-a:2′,3′-c]phenazine, dppz, and pyrazino[2,3-f][1,10]-phenanthroline, ppl, have been used. Quinonic residues were fused to these basic units to improve acceptor properties. Photophysical studies were performed in order to test theoretical predictions.

‣ Effect of di-(2-ethylhexyl) phthalate on N-cadherin and catenin protein expression in rat testis

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
This study investigated the effect of DEHP exposure on N-cadherin and α-, β- and p120-catenin immunoreactivities in the rat testis. DEHP was administered by daily gavage to 25-day-old male Sprague-Dawley rats at a dose of 2 g DEHP/5 ml corn oil/kg body weight for 2 days or 7 days. Control rats were treated with corn oil vehicle under the same conditions. Animals were killed at 24 h after the last treatment. Another group of rats treated with DEHP or corn oil vehicle (control group) for 2 days were held for 30 days without treatment to observe recovery. Testes were analyzed for histopathology, TUNEL staining, immunofluorescence (IF) and Western blot analyses. Animals exposed to DEHP for 2 days or 7 days showed severe alterations of seminiferous tubules characterized by germ cell sloughing. Animals from the longer term recovery group treated with DEHP showed foci of delayed spermatogenesis. A linear and continuous pattern of N-cadherin was observed in the basal compartment of the seminiferous tubules. A similar pattern but with higher IF intensity was observed for N-cadherin in rats treated with DEHP for 2 days or 7 days, compared to control animals. The α-, β- and p120-catenins were detected in the basal compartment of seminiferous tubules in similar localization and IF pattern for DEHP and control groups. A significant increase in testicular N-cadherin and α-catenin levels was detected by Western blot analysis in DEHP-exposed versus control rats. No variations in N-cadherin or catenin expression were detected in the recovery groups. These findings demonstrate that DEHP induces an up-regulation of N-cadherin and α-catenin expression and may perturb cell-cell adhesion phenomena in the seminiferous tubule.

‣ Trace metals in microcrustaceans and Brazilian waterweed from a contaminated Chilean wetland using total reflection X-ray fluorescence spectrometry

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The trace element content of individual copepod specimens and of the Brazilian water weed (Egeria densa) from a metal-contaminated wetland in Southern Chile were determined using total reflection X-ray fluorescence spectrometry. Sampling of the water and the organisms was carried out at three sampling sites during 2004. Enhanced concentrations of dissolved Fe and Mn were found in the column water and in the pore water. The Fe content in the benthic copepods was significantly elevated compared to other aquatic organisms from different Chilean lakes. Regarding E. densa, healthy (green coloured) plants showed mass fractions of Fe, Mn, Ni, Cu and Zn which were typical for uncontaminated systems. In contrast, damaged (brownish coloured) plants exhibited very high Fe and Mn concentrations indicative of contamination or processes which changed the element load from the environment to the plant.

‣ La Responsabilidad Social en la Universidad Católica de Temuco: Resultados de la encuesta 2005 y catastro de experiencias

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Libro
Português
Este documento contiene dos aportes concretos a la validación y posicionamiento del valor de La Responsabilidad Social Universitaria en La Universidad Católica de Temuco: 1. Los resultados de una Encuesta de Percepción de la Responsabilidad Social en La Universidad realizada a fines del segundo semestre del pasado año 2005. 2. Un primer catastro de Experiencias no Institucionales de solidaridad y compromiso social que creemos reflejan de forma "natural" la responsabilidad social de muchos de los integrantes de la Comunidad Universitaria, en especial de los estudiantes.

‣ Análisis cualitativo y cuantitativo del semen de puye Galaxias Maculatus (Jenyns, 1842) (Salmoniformes:Galaxiidae)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
En la presente investigación se estudió cuali y cuantitativamente el semen del puye (Galaxias maculatus). Para ello se capturaron especímenes adultos (6,24 IT 0,84 cm de longitud estándar) de aguas límnicas del Sur de Chile y luego fueron mantenidos en cautiverio. Una vez maduros, diez especímenes fueron anestesiados y mediante masaje abdominal se les extrajo una muestra de semen que se sometió a examen visual, recuento espermático, espermatocrito y motilidad. Los resultados obtenidos muestran que el semen del puye es poco abundante (máximo 0,2 m1 por individuo), de color blanquecino y gran viscosidad. Cuantitativamente se encontró un promedio de 55,3 x lo6 espermatozoides/ml, un espermatocrito de 89,63 % y una correlación entre ambas variables de r=0,97. La motilidad frente a distintos activadores es muy baja y sólo se observó una motilidad igual a 2 (en una escala de O a 5) por aproximadamente 30 min al utilizar un activador en base a carbamida.