Functional and structural optimization of the respiratory system of the bat Tadarida brasiliensis (Chiroptera, Molossidae): does airway geometry matter?

We studied structure and function of the respiratory system in the bat Tadarida brasiliensis and compared it with those of two species of rodents, Abrothrix andinus and A. olivaceus. Tadarida brasiliensis had lower resting oxygen consumption, but higher maximum oxygen consumption and aerobic scope, than the rodents.

A radiographic method to estimate lung volume and its use in small mammals.

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.

Thermal acclimation and seasonal variations of erythrocyte size in the Andean mouse Phyllotis xanthopygus rupestris.

Seasonal hematological adjustments in small mammals may include changes in the number and size of the red cells or changes in other linked blood parameters. The direction and magnitude of these changes vary in different species. We hypothesized that the observed variations of the red cell adjustments could be directly related to the magnitude of the seasonal temperature differential, and predicted that the annual red cell size variation in rodents from environments with marked seasonal changes would tend to disappear, if the animals were raised under milder and constant environments.

A simple geometrical pattern for the branching distribution of the bronchial tree, useful to estimate optimality departures.

The design of the bronchial tree has largely been proposed as a model of optimal design from a physical-functional perspective. However, the distributive function of the airway may be more related to a geometrical than a physical problem. The bronchial tree must distribute a three dimensional volume of inspired air on a two dimensional alveolar surface, included in a limited volume.

Energetics and torpor of a South American "living fossil", the microbiotheriid Dromiciops gliroides.

We examined the energetics of the living fossil microbiotheriid Dromiciops gliroides, a nocturnal and rare small marsupial, endemic to the northern portion of the temperate forest of southern South America. We investigated the effects of changes at ambient temperature and food restriction on the energetics and patterns of torpor. We determined whether they exhibit shallow daily torpor or deep prolonged torpor like some Australian marsupials.

Departures from the physical optimality in the bronchial tree of rats (Rattus norvegicus).

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 criteria.

Energetics and food requirements of the female snake Phillodryas chamissonis during the breeding season.

1.The energetic performance and food requirements of female Phillodryas chamissonis was determined during its breeding season at different ambient temperatures. 2.

Bioenergetics and food preferences in sympatric southern Chilean rodents.

Ecological divergences in two congeneric sympatric woodland rodents, Akodon olivaceus brachiotis and Akodon longipilis apta (Family Cricetidae) was demonstrated from determination of energetic bud gets and food preferences. It was found that each species posseses a different bioenergetic strategy. The heavier (A.