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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‣ Lethal effects of ultraviolet radiation under different concentrations of dissolved organic carbon on Neobosmina chilensis (Daday, 1902) (Cladocera, Bosminidae)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The increase in the penetration of ultraviolet radiation that has been reported lately for freshwater ecosystems in southern South America, would allegedly generate alterations in ecological processes. In the present study, the mortality of Neobosmina chilensis (Daday 1902), a small cladoceran distributed in South American lakes and ponds, was studied in this respect. Specimens were reared in five different concentrations of dissolved organic carbon, and subjected to 24 hrs of exposure to artificial ultraviolet radiation. An inverse correlation between the dissolved organic carbon concentration and individual mortality was found. This result supports the description of a screen effect of dissolved organic carbon against ultraviolet radiation. The data obtained describe a linear relation, in which LC50 corresponded to 4.43 mg/l of dissolved organic carbon. The ecological implications of this result are discussed.; El incremento de la penetración de la radiación ultravioleta ha sido reportado para ecosistemas lacustres en el sur de Sudamérica, y genera alteraciones en procesos ecológicos. En el presente trabajo, se estudió la mortalidad de Neobosmina chilensis (Daday, 1902), un cladócero de pequeño tamaño corporal distribuido en lagos y lagunas de América del Sur. Los especímenes fueron mantenidos por 24 horas bajo cinco concentraciones de carbono orgánico disuelto...

‣ The effect of physical and chemical parameters on the structure and composition of the phytoplankton community of Lake Budi (IX Region, Chile)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The chemical characteristics of the waters of Lake Budi (IX Region, Chile), in winter and summer were analysed in order to establish seasonal variations and determine their influence on the various phytoplankton components. On the basis of the results it was possible to indicate that the chemical parameters found in the water body under examination vary in time and space, giving rise to different algal communities. The strong influence of salinity on the phytoplankton communities in both study periods appears to result principally from the influence of the sea, resulting from the intrusion of salt water during certain periods of the year. The predominant chemical characteristic in summer indicates a slight reduction in water quality, due to a rise in temperature and a reduction in the oxygen concentration.

‣ Macrofauna bentónica de los humedales de tres lagos salinos en el borde costero del sur de Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
A coastal-lake wetland is a type of inland water ecosystem that does not occur very frequently in Chile, of which lakes Budi, Huillinco and Cucao are examples. Textural differences were found in the various constituent parts of the coastal lake sediments. Gravel was the smallest fraction and showed significant differences among the three coastal lakes (P < 0.05). Significant differences (P < 0.05) were also recorded for the sand and mud fractions. Lakes Cucao and Huillinco are described as muddy sand, in contrast to Lake Budi, which is described as sandy mud, composed primarily of mud with a smaller percentage of sand. There were statistical differences among the lakes with regard to the contributions of organic matter in each fraction. The macrofauna in these bodies of water belongs to the fauna inhabiting estuary environments in southern Chile. Lake Budi had seven taxa, and lakes Huillinco and Cucao ten species of macrofauna each. There were no significant differences in the number of species captured at the three coastal lakes (P > 0.05), but differences did emerge in comparisons made among the sampling stations. Total abundances showed significant differences (P < 0.05) in comparisons made both among the lakes and the stations. Salinity and grain size could be limiting the density and number of species at the lakes.

‣ Vitrificacion de blastocitos bovinos producidos in vitro con el método Open Pulled Straw (OPS): Primer reporte

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
El objetivo de este trabajo fue presentar los primeros resultados exitosos de vitrificación de blastocistos bovinos producidos in vitro utilizando la técnica del Open Pulled Straw (OPS) en nuestro país. Para la confección de las OPS, pajuelas plásticas de 0.25 ml fueron estiradas utilizando calor. Los 93 blastocistos seleccionados para la vitrificación fueron depositados individual y secuencialmente en las soluciones de vitrificación 1 y 2 consistentes en TCM199 (20% SFB) adicionado con Etilénglicol y Dimetilsulfoxido (DMSO), por períodos de un minuto y 20 segundos respectivamente. Durante este último período el embrión fue cargado con una micropipeta, en un volumen de 2 µl, depositándose sobre una placa petri desde la cual fue cargado por capilaridad en la pajuela estirada, para luego depositarla directamente en el nitrógeno líquido. El 89% de los blastocistos congelados fueron recuperados post descongelación, de los cuales 54% se encontraban re-expandidos o eclosionados a las 24 horas de cultivo. Al evaluar los embriones a las 72 horas post descongelación se observó un 29% de embriones eclosionados. Aunque levemente inferiores a resultados reportados en la literatura, los nuestros indican la factibilidad de vitrificar exitosamente blastocistos bovinos producidos in vitro utilizando el método de Open Pulled Straw.; The purpose of this work is to present preliminary produced in vitro using the Open Pulled Straw (OPS) method. Open Pulled Straws were made by pulling 0.25 ml inner and outer diameter were reduced to half of their original and deposited individually in vitrification solutions 1 and dimethyl - sulfoxide (DMSO)...

‣ Influence of trophic status and conductivity on zooplankton composition in lakes and ponds of Torres del Paine National Park (Chile)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The Torres del Paine National Park is located in the southern Chilean Patagonia. This park has numerous and heterogeneous lakes and ponds with different trophic status and zooplankton composition. The aim of this study was to analyze the influence of trophic status and conductivity on zooplankton assemblages in lakes and ponds within the Torres del Paine National Park. The water bodies described in the present study were previously classified in three groups. The first group consisted of large, deep and oligotrophic lakes with fish populations, low zooplankton species diversity and high predominance of calanoid copepods of small body size. The second group contained small mesotrophic lakes with fish populations and relatively high predominance of small sized daphnids. The third group consisted of fishless ponds of different trophic status, wide conductivity gradient and with zooplankton species of relatively large body size. The results show that Daphnids abundance was directly related to chlorophyll-a concentration and inversely associated with conductivity. Calanoids abundance was also directly associated with conductivity.

‣ Characterization of Toxoplasma gondii isolates in free-range chickens from Chile, South America

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in 85 free-range chickens (Gallus domesticus) from Chile was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT), and found in 47 of 85 (55.3.9%) chickens with titers of 1:5 in six, 1:10 in four, 1:20 in four 1: 40 in three, 1: 80 in nine, 1: 160 in four 1:320 in nine, and 1: 640 or higher in eight. Hearts and brains of 47 chickens with titers of 1:5 or higher were pooled for each chicken and bioassayed in mice. Tissues from 16 seronegative (MAT < 1:5) chickens were pooled and fed to one T. gondii-free cat. Feces of the cat were examined for oocysts but none was found based on bioassay of fecal floats in mice. Hearts and brains from seven seronegative (<1:5) were pooled and bioassayed in mice; T. gondii was not isolated. T. gondii was isolated by bioassay in mice from 22 chickens with MAT titers of 1:20 or higher. Genotyping of these 22 isolates using polymorphisms at the loci SAG1, SAG2, SAG3, BTUB and GRA6 revealed three genotypes. Seventeen isolates had type II alleles and four isolates had type III alleles at all loci. One isolate contained the combination of type I and III alleles. This is the first report of genetic characterization of T. gondii isolates from Chile...

‣ Micropogonias manni as a bioindicator for copper in Lake Budi (IX Region, Chile)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
This study determined the concentration of copper in the species Micropogonias manni, a fish found in Lake Budi, which is much consumed by the population of Puerto Dominguez, IX Region of Chile. The determinations were done by atomic absorption spectrometry with flame, taking into account the sex, weight and size of the species, and, as representative samples, liver and muscle tissue. The validation of the methodology was done by using certified reference material (fish muscle), The copper concentration found in the liver fluctuated between 3,1 - 323,4 μg g-1, while for muscle tissue it was between 0,7 - 27,0 μg g-1, dry weight. The maximum copper values found in muscle tissue, are greater than those found by other authors in various fish species. Statistical analysis showed that in muscle tissue, the sex, length and weight variables have no bearing on copper concentration; however, in the liver, the length and weight variables are significant.

‣ Chromosome numbers of Chilean pteridophytes: First contribution

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Mitotic chromosome counts in Chilean pteridophytes confirm the diploidy described for Equisetum L. (2n = 216) and Blechnum L. (2n = 66), as well as the tetraploidy of Asplenium L. (2n = 144). Megalastrum spectabile (Kaulf.) A.R.Sm. et R.C.Moran is diploid (2n = 82), while in metaphases of Polystichum subintegerrimum (Hook. et Arn.) R.A.Rodr. chromosome numbers from ca. 311 to 328 were counted. Tetraploidy was also described in Adiantum chilense Kaulf. (2n = 116).

‣ Estado de conocimiento de los bivalvos dulceacuicolas de Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The current knowledge about the Chilean freshwater bivalves is presented. The bivalves described at present are adscribed to two families: Hyriidae represented only by the genus Diplodon with two species (D. chilensis and D. solidulus) and Sphaeriidae represented by three genera: Pisidium with seven species (P. chilense, P. magellanicum, P. lebruni, P. observationis, P. meierbrooki, P. huillichum and P. llanquihuense), Sphaerium with two species (S. lauricochae and S. forbesi), and Musculium with two species (M. argentinum and M. patagonicum). Subgeneric and subspecific taxa are recognized for Hyriidae only. Pisidium chilense, P. huillichum, P. llanquihuense P. lebruni and D. solidulus are proposed as endemic species for Chile. It is allocated the geographic distribution of the species, the taxonomic implications of the phenotypic variations exhibited by hyrids, the causes of the declination of the populations and the lack of knowledge in both families are analyzed. Specialists on the field and the available collections are listed.; Se presenta el estado actual del conocimiento de los bivalvos dulceacuícolas chilenos. Las especies descritas a la fecha, pertenecen a las familias Hyriidae, representada sólo por el género Diplodon con dos especies (D. chilensis y D. solidulus) y Sphaeriidae con tres géneros: Pisidium con siete especies (P. chilense...

‣ Visión sinóptica de los macrofitos dulceacuicolas de Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
By means of a bibliographic review, a panorama of the state of art of the vascular macrophytes of chilean continental aquatic systems was carried through. 455 species of aquatic macrophytes were registered, 3 of them belonging to Gymnospermae, 15 to Pteridophytes, 184 to Monocotyledoneae and 253 to Dicotyledoneae. Only 62 of the total are typical hidrophytes. The total of the macrophytes represents 8,7% of the continental chilean flora, and the hidrophytes, only 1,2%. In terms of phytogeographic origins, the high percentage of native species is outstanding (79,3%) in relation to the introduced species (20,7%). In terms of their conservation state, only Gymnospermae and Pteridophytes have this condition clearly defined; of the 18 registered species in these two groups, 4 are considered "endangered", 3 "vulnerable", and 2 "rare". The lack of the corresponding studies referring to the rest of the species is a clear sign that this topic has to be urgently considered, together with the taxonomic study of important family genera, such as Cyperaceae, Juncaceae and Potamogetonaceae, in addition to antecedents about their ecophysiology.; En base a revisión bibliográfica, se realizó una sinopsis del estado del arte de las macrófitas vasculares de ecosistemas acuáticos continentales de Chile. Se registró un total de 455 especies de macrófitas acuáticas...

‣ Ensayos de tolerancia al aluminio de Bromus stamineus y Bromus lithobius Recolectados en el sur de Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
A study was made on the effects of several soil treatments on different ecotypes of plants of the genus Bromus to determine the tolerance to aluminum under different soil condition. For the first step, out of 20 ecotypes of Bromus lithobius and Bromus stamineus, the ecotypes PRO 95-18, PRO 94-25, PRO 94-24, PRO 94-49 and PRO 94-4 were selected, as they represented a declining order of tolerance to aluminum. Root growth of all the ecotypes was evaluated over four day exposures in aluminum solutions at 0, 20, 40, 80 and 160 mM. A second stage of testing was carried out in soil containing 42.6% saturation of aluminum, modified by three doses of calcium carbonate. Evaluation was made of dry root material produced, as well as concentrations of aluminum in the roots and leaves. It was concluded that behavior of the plants was different between the solution tests and the soil tests due to different mechanisms of tolerance, of which ecotype PRO 94-49 was outstanding in its tolerance to aluminum under soil test conditions.; Se han estudiado los efectos de los diferentes tratamientos sobre el desarrollo de distintos ecotipos de plantas del género Bromus para determinar la tolerancia al aluminio en diferentes condiciones de suelo. En una primera etapa se seleccionaron los ecotipos PRO 95-18...

‣ Maduración in vitro de ovocitos de gatas tratadas con hormona folículo estimulante (FSH)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The aim of this research was to evaluate the effect of Follicle Stimulating Hormone (FSH) treatment on quality and in vitro maturation potential of cumulus-oocyte complexes (COCs) recovered from domestic cats. Twenty-one mature cats were randomly assigned to two groups, FSH (n=9) and Control (n=12). Cats in FSH group were treated with 5 mg of Folltropin-V subcutaneously every 24 hours, for 4 consecutive days. Cats in Control group received 1 mL of sterile saline solution every 24 hours for 4 days. Ovaries were obtained surgically 24 hours after the end of the gonadotrophic treatment. Ovaries were then transported to the laboratory at 37°C within 4 hours after surgery. COCs were recovered by slicing, and classified according to morphological features. Maturation medium was based on TCM-199, and supplemented with 0.4% BSA, 1μL/mL FSH, 1μL/mL LH y 1μg/mL of 17β oestradiol, 50 μg/mL gentamicin, 0.20 mM sodium pyruvate. The maturation period was of 24 hours under 38.5°C, 5% CO 2 and saturated humidity. After this period oocytes were denuded, fixed and stained to asses their maturational status. Oocytes were considered mature when it was observed the presence of metaphase II plate and the expulsion of the first polar body. An average of 10.6 ± 3.6 and 7.1 ± 2.8 excellent and good quality COCs were recovered from cats in FSH and Control group respectively (P ≤ 0.05). Twenty five point six percent (25.6%) and 17% of recovered COCs from FSH and Control group respectively were classified as excellent or good (P ≤ 0.05). In vitro maturation rate was of 73.6% and 49.4% for the FSH group and the control group respectively (P ≤ 0.05). It can be concluded that FSH treatment increases the number of excellent and good quality oocytes obtained from cats and that these oocytes present a higher in vitro maturation potential.

‣ Detección de anticuerpos contra Brucella spp. y caracterización del tipo de explotación en cabras de la veranada Marimenuco, comuna de Lonquimay, Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Chile is free of B. melitensis since 1975, but B. abortus is still present and also can infect goats. In Argentina there are both organisms. This situation is a potential risk for Chilean herds that use common summer grazing areas near the border with Argentina. The aim of this study was to determine brucellosis antibody status in goats at common summer grazing areas and the productivity of local goat farms. A commercial Bengal Rose test was performed to 630 adult goat sera. Blood samples were taken from 30 herds at risk from the summer grazing area of Marimenuco, Lonquimay county. A questionnaire about herds productivity and farm characteristics was performed at sampling time at the same farms. All sera were antibody negative against Brucella spp. (smooth strains). The median farm size was 6 hectares. The median herd size was 35.5. The average fertility rate was 75%, culling rate was 15%, birth-weaning mortality rate was 12% and lambing ratio was 0.89. Except for the birth-weaning mortality rate all the performance indices differed statistically from references values. It was concluded that the studied herds had no antibodies against Brucella spp. (smooth strains) at the time that the survey was performed. Sanitary conditions, management and trade practices suggest that goats are farmed in a traditional subsistence system. The productivity indices could be improved to became closer to the references values.

‣ Effects of the availability of energetic and protective resources on the abundance of daphniids (Cladocera, Daphniidae) in Chilean Patagonian lakes (39°-51°S)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The lacustrine zooplankton of Chile is characterized by a low abundance of daphniid cladocerans and a predominance of calanoid copepods, thus making up a zooplankton community quite different from that described for North American lakes. To explain this pattern, this study investigates the role of the oligotrophy, and the resulting high transparency of a considerable number of locations. Due to low levels of dissolved organic carbon, viz., Daphniidae are exposed to ultraviolet radiation. Chilean lakes located between 39° and 51°S were studied, and maximum depth, mixing depth, trophic status, and dissolved organic carbon concentrations were measured and considered. The results obtained revealed that daphniids were abundant in oligo-mesotrophic lakes with shallow mixing depth. Thus, daphniid abundance is directly associated with chlorophyll-a concentration as an energetic resource, but also with sufficient depth, because this last condition provides protection against the penetration of ultraviolet radiation.

‣ Pesticide levels in surface waters in an agricultural-forestry basin in Southern Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Residues of five pesticides in surface water were surveyed during 2001 and 2003 in the Traiguén river basin in Southern Chile. Simazine, hexazinone, 2,4-D, picloram herbicides and carbendazim fungicide were selected through a pesticide risk classification index. Six sampling stations along the river were set up based on agricultural and forestry land use. The water sampling was carried out before and after the pesticide application periods and in correspondence to some rain events. Pesticides were analyzed by HPLC with DAD detection in a multiresidue analysis. During 2001, in the first sampling campaign (March), the highest concentrations of pesticides were 3.0 μg l -1 for simazine and hexazinone and 1.8 μg l-1 for carbendazim. In the second sampling (September), the highest concentration were 9.7 μg l-1 for 2,4-D, 0.3 μg l-1 for picloram and 0.4 μg l-1 for carbendazim. In the last sampling period (December), samples indicated contamination with carbendazim fungicide at levels of up to 1.2 μg l-1. In sampling carried out on May 2003, no pesticides were detected. In October 2003, the highest concentrations of pesticides were 4.5 μg l-1 for carbendazim and 2.9 μg l -1 for 2,4-D. Data are discussed in function of land use and application periods of the products...

‣ La Calidad de las Aguas en los Ríos Cautín e Imperial, IX Región-Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
El objetivo de este trabajo fue establecer la calidad descriptiva de agua de los ríos Cautín e Imperial que conforman la cuenca hidrográfica del río Imperial ubicada en la IX Región de la Araucanía-Chile. La caracterización fisicoquímica y microbiológica se efectuó fijando diez estaciones de muestreo. Los resultados muestran que las aguas de estos ríos no presentan problemas fisicoquímicos, de acuerdo a las normas chilenas oficiales. En la parte microbiológica se encontró un recuento alto de bacterias coliformes totales en algunas estaciones de muestreo, lo cual les da el carácter de no aptas para actividades con contacto directo y para el riego de verduras y frutas que se desarrollan a ras de suelo. Se puede predecir que una disminución del caudal de los ríos en el estiaje, provocará la mayor modificación del ecosistema, situación que se hace más crítica por la falta de un plan de manejo integral adecuado.; The objective of this work was to establish the descriptive water quality of the Cautín and Imperial rivers which form the Imperial River hydrographic basin in the IX Region of Araucanía, Chile. Physicochemical and microbiological evaluations were made at ten sampling stations. Physicochemical parameters measured in these rivers did not exceed the legally established Chilean water criteria. Microbiological testing showed high counts of coliform bacteria at some stations...

‣ Números cromosómicos en especies chilenas de Luzuriaga ruiz et PAV. (Luzuriagaceae)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Mitotic chromosome counts for Luzuriaga radicans Ruiz et Pav. and L. polyphylla (Hook) J.F. Macbr. from Chile, reported here for the first time, are the same as those reported for L. parviflora (Hook) Kunth in New Zealand and L. marginata (Gaertner) Benth. on Falkland Islands (2n = 2x = 20). These results indicate a constancy of chromosome number in the genus Luzuríaga.

‣ Shared knowledge: The result of negotiation in non-hierarchical environments

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The knowledge building can be seen as a collaborative process of which negotiation is a fundamental aspect. The use of technology to support this process has been attempted in various groupware systems. However, there is no adequate support system for the process of negotiation, which generally relies on voting as the element for reaching agreement in decision-making. On the other hand, the best approaches to this problem have been formalised in learning environments where there is a clear hierarchical structure. When the environment is not hierarchical, new problems arise which require special attention. This article presents a model of knowledge building that has negotiation as its basis in a group that is non-hierarchical in its structure. The model is implemented on a prototype tool named ShaKnoMa, which is tested on common tasks in an environment such as that proposed here. For the knowledge representation, concept maps are used which act a scaffolding to classify, index and search the information.

‣ Simplificación en el uso de macroinvertebrados en la evaluación de la calidad de las aguas en sistemas fluviales

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Macroinvertebrates have been used for decades to evaluate water quality, using measures of diversity, biotic indexes and comparative analysis. The taxonomic level of family allows a general interpretation of the ecological quality of a fluvial system, and is possible to infer the quality of these systems compared to selected references sites. This paper analyzed three localities of Central-South Chile by means of grouping analysis, evaluating if there is any loss of information when using two hierarchic levels. It is shown that the family level of benthic macroinvertebrates is sufficient for environmental monitoring. The practical advantages, the integrating capacity that can be reached and its relation with environmental variables are discussed.; Los macroinvertebrados han sido utilizados por décadas para evaluar la calidad de las aguas, utilizando medidas de diversidad, índices bióticos y comparativos, sugiriendo que el nivel taxonómico de familia permite una buena interpretación general de la calidad ecológica de un sistema fluvial y es posible hacer inferencias sobre la calidad de éstos sistemas respecto a condiciones de referencias seleccionadas. Este trabajo analiza independientemente tres localidades de Chile centro-sur...

‣ El cariotipo de Lapageria rosea Ruiz et Pav. (Liliales: Philesiaceae)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Lapageria rosea Ruiz et Pav. showed an asymmetric and bimodal karyotype 2n = 2x = 30, with three metacentric, six submetacentric and six subtelocentric chromosome pairs. One B chromosome pair was also observed. The total chromosome length (2n) was 131.3 + 0.22 μm.