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| 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 ≈ 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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