Consulta: creatorFacets:"OLIVARES,RICARDO"
Registros recuperados: 6
Data/hora: 07/06/2024 05:45:01

Comparación de la morfología alar de Tadarida brasiliensis (Chiroptera: Molossidae) y Myotis chiloensis (Chiroptera: Vespertilionidae), representantes de dos diferentes patrones de vuelo
Provedor de dados: 97
Autores: CANALS,MAURICIO; IRIARTE-DÍAZ,JOSÉ; OLIVARES,RICARDO; NOVOA,F. FERNANDO.
La morfología alar de los quirópteros se encuentra relacionada por una parte con la biomecánica y energética del vuelo y por otra parte con aspectos ecológicos y conductuales (i.e., patrón de vuelo, conducta de forrajeo y selección de hábitat y de presas). En este trabajo se compara la morfometría alar de Tadarida brasiliensis (Molossidae) y Myotis chiloensis (Vespertilionidae), representantes de diferentes patrones de vuelo, buscando compromisos entre la morfometría alar y aspectos ecológicos y conductuales. Nuestros resultados muestran que T. brasiliensis es un murciélago más robusto, de mayor envergadura, pero con un área alar similar a la de M. chiloensis. Esta última especie tiene una menor variabilidad en su masa y área cortical del húmero, que...
Tipo: Journal article
Palavras-chave: Tadarida brasiliensis; Myotis chiloensis; Morfología alar; Vuelo; Biomecánica.
Ano: 2001
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000300015

La asimetría y el grado de optimización del árbol bronquial en Rattus norvegicus y Oryctolagus cuniculus
Provedor de dados: 97
Autores: CANALS,MAURICIO; ATALA,CRISTIAN; OLIVARES,RICARDO; NOVOA,F. FERNANDO; ROSENMANN,MARIO.
La vía aérea ha sido propuesta como modelo de diseño óptimo desde una perspectiva física. Su diseño se ha asociado con un adecuado flujo de gases a los alvéolos, una mínima producción de entropía y un mínimo costo en materia y energía. Se ha propuesto un decrecimiento exponencial del diámetro de los bronquios (dG) en función de la generación: dG = do·2-G/3, asociado a una mínima producción de entropía. También se ha propuesto un modelo de renormalización: dG = An·G-u donde u es un exponente y An una función que introduce desviaciones periódicas en la escala, es decir más de una escala, evitando la propagación distal de errores aleatorios en el calibre de un bronquio. Sin embargo, este último resultado podría ser consecuencia en árboles asimétricos de la...
Tipo: Journal article
Palavras-chave: Optimización; Bronquios; Asimetría; Modelos.
Ano: 2002
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2002000200001

A radiographic method to estimate lung volume and its use in small mammals
Provedor de dados: 48
Autores: CANALS,MAURICIO; OLIVARES,RICARDO; ROSENMANN,Mario.
In this paper we develop a method to estimate lung volume using chest x-rays of small mammals. We applied this method to assess the lung volume of several rodents. We showed that a good estimator of the lung volume is: V*L = 0.496 · V RX &amp;#8776; 1/2·V RX , where V RX is a measurement obtained from the x-ray that represents the volume of a rectangular box containing the lungs and mediastinum organs. The proposed formula may be interpreted as the volume of an ellipsoid formed by both lungs joined at their bases. When that relationship was used to estimate lung volume, values similar to those expected from allometric relationship were found in four rodents. In two others, M. musculus and R. norvegicus, lung volume was similar to reported data, although...
Tipo: Journal article
Palavras-chave: Lung volume; X-ray; Method; Rodents.
Ano: 2005
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602005000100006

Ontogenetic changes in the fractal geometry of the bronchial tree in Rattus norvegicus
Provedor de dados: 48
Autores: CANALS,MAURICIO; OLIVARES,RICARDO; LABRA,FABIAN; NOVOA,FRANCISCO F.
Respiration and metabolism change dramatically over the course of the development of vertebrates. In mammals these changes may be ascribed to organogenesis and differentiation of structures involved in gas exchange and transport and the increase in size. Since young as well as mature individuals must be well-designed if the species is to survive, the physiological changes during the development should be matched with geometrical or structural adjustments of the respiratory system. The aim of this study was to evaluate changes in the fractal geometry of the bronchial tree during the postnatal development of the rat.  The average fractal dimension of the bronchial tree of the rats was 1.587, but that of juveniles was larger than that of the adults. We found...
Tipo: Journal article
Palavras-chave: Bronchial tree; Fractals; Ontogeny.
Ano: 2000
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000100010

Departures from the physical optimality in the bronchial tree of rats (Rattus norvegicus)
Provedor de dados: 48
Autores: CANALS M,MAURICIO; ATALA,CRISTIAN; OLIVARES,RICARDO; NOVOA,FRANCISCO F; ROSENMANN,MARIO.
We studied the departure from the physical optimality of the bronchial tree of rats using both i) the minimum volume and power and ii) the minimum surface and drag criteria, considering the bronchial junction as the unit study based on Zamir's model for vascular trees. Our results show deviations of the junctions of the bronchial tree from the expected optimums in the proximal airway that can be explained by both, the turbulent or transitional flow regime, and the airway's necessity to distribute its terminal branches in the alveolar surface filling the thoracic volume. The departures of the observed values at the optimum for the minimum volume and power were significantly different than the obtained departure values for the minimum surface and drag...
Tipo: Journal article
Palavras-chave: Lung; Junction optimality; Optimization; Broncography.
Ano: 2002
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000300015

Interplay between the morphometry of the lungs and the mode of locomotion in birds and mammals
Provedor de dados: 48
Autores: FIGUEROA,DANIELA; OLIVARES,RICARDO; SALABERRY,MICHEL; SABAT,PABLO; CANALS,MAURICIO.
We studied the lung diffusion parameters of two species of birds and two species of mammals to explore how structural and functional features may be paralleled by differences in life style or phylogenetic origin. We used two fast-flying species (one mammal and one bird), one running mammal and one bird species that flies only occasionally as models. The harmonic mean thickness of the air-blood barrier was very thin in the species we studied. An exception was the Chilean tinamou Notoprocta perdicaria, which only flies occasionally. It showed an air-blood barrier as thick as that of flightless Galliformes. We found that the respiratory surface density was significantly greater in flying species compared to running species. The estimated values for the oxygen...
Tipo: Journal article
Palavras-chave: Diffusing capacity; Lungs; Flight.
Ano: 2007
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602007000200010