Comparative physiology of Australian quolls (Dasyurus; Marsupialia)

Quolls (Dasyurus) are medium-sized carnivorous dasyurid marsupials. Tiger (3,840 g) and eastern quolls (780 g) are mesic zone species, northern quolls (516 g) are tropical zone, and chuditch (1,385 g) were once widespread through the Australian arid zone. We found that standard physiological variables of these quolls are consistent with allometric expectations for marsupials. Nevertheless, inter-specific patterns amongst the quolls are consistent with their different environments. The lower T ^sub b^ of northern quolls (34°C) may provide scope for adaptive hyperthermia in the tropics, and they use torpor for energy/water conservation, whereas the larger mesic species (eastern and tiger quolls) do not appear to. Thermolability varied from little in eastern (0.035°C °C^sup -1^) and tiger quolls (0.051°C ºC^sup -1^) to substantial in northern quolls (0.100°C ºC^sup -1^) and chuditch (0.146°C ºC^sup -1^), reflecting body mass and environment. Basal metabolic rate was higher for eastern quolls (0.662 ± 0.033 ml O^sub 2^ g^sup -1^ h^sup -1^), presumably reflecting their naturally cool environment. Respiratory ventilation closely matched metabolic demand, except at high ambient temperatures where quolls hyperventilated to facilitate evaporative heat loss; tiger and eastern quolls also salivated. A higher evaporative water loss for eastern quolls (1.43 ± 0.212 mg H^sub 2^O g^sup -1^ h^sup -1^) presumably reflects their more mesic distribution. The point of relative water economy was low for tiger (-1.3°C), eastern (-12.5°C) and northern (+3.3) quolls, and highest for the chuditch (+22.6°C). We suggest that these differences in water economy reflect lower expired air temperatures and hence lower respiratory evaporative water loss for the arid-zone chuditch relative to tropical and mesic quolls

Behavioral Synthesis Methodology for HDL-Based Specification and Validation

This paper describes a HDL synthesis based design methodology that supports user adoption of behavioral-level synthesis into normal design practices. The use of these techniques increases understanding of the HDL descriptions before synthesis, and makes the comparison of pre- and post-synthesis design behavior through simulation much more direct. This increases user confidence that the specification does what the user wants, i.e. that the synthesized design matches the specification in the ways that are important to the user. At the same time, the methodology gives the user a powerful set of tools to specify complex interface timing, while preserving a user's ability to delegate decision-making authority to software in those cases where the user does not wish to restrict the options available to the synthesis algorithms. 1.0 Overview This paper describes a synthesis methodology that uses high-level synthesis (HLS) of behavioral hardware-description language (HDL) descriptions. HLS h..

Mass‐independent maximal metabolic rate predicts geographic range size of placental mammals

Understanding the mechanisms driving geographic range sizes of species is a central issue in ecology, but remarkably few rules link physiology with the distributions of species. Maximal metabolic rate (MMR) during exercise is an important measure of physiological performance. It sets an upper limit to sustained activity and locomotor capacity, so MMR may influence ability to migrate, disperse and maintain population connectivity. Using both conventional ordinary least squares (OLS) analyses and phylogenetically generalized least squares (PGLS), we tested whether MMR helps explain geographic range size in 51 species of placental mammals. Log body mass alone (OLS r =.074, p =.053; PGLS r =.016, p =.373) and log MMR alone (OLS r =.140, p =.007; PGLS r =.061, p =.081) were weak predictors of log range size. However, multiple regression of log body mass and log MMR accounted for over half of the variation in log range size (OLS R =.527, p <.001). The relationship was also strong after correcting for the phylogenetic non-independence (PGLS R =.417, p <.001). In analyses restricted to rodents (34 species), neither log body mass alone (OLS r =.004, p =.720; PGLS r =.003, p =.77) nor log MMR alone was useful in predicting log geographic range size (OLS r =.008, p =.626; PGLS r =.046, p =.225), but multiple regressions of log body mass and log MMR accounted for roughly a third to a half of the variation in log range size (OLS R =.443, p <.001, PGLS R =.381, p <.001). Mass-independent MMR is a strong predictor of mass-independent geographic range size in placental mammals. The ability of body mass and MMR to explain nearly 50% of the variation in the geographic ranges of mammals is surprising and powerful, particularly when neither variable alone is strongly predictive. A better understanding of MMR during exercise may be important to understanding the limits of geographic ranges of mammals, and perhaps other animal groups.M.B.A. is funded through the NICHE project (CGL2011‐26852) of the Spanish Ministry of Economy and Competitiveness and the Spanish Research Council (CSIC), the Rui Nabeiro Biodiversity Chair and the Danish NSF. M.B.A. acknowledges support from FCT project PTDC/AAG‐MAA/3764/2014.Peer Reviewe

Differential osmoregulatory capabilities of common spiny mice (Acomys cahirinus) from adjacent microhabitats

The osmoregulatory function of common spiny mice Acomys cahirinus living on opposite slopes of the lower Nahal Oren (‘Evolution Canyon’) on mount Carmel, Israel, was investigated by increasing the salinity of the water source whilst maintaining a high-protein diet. The southern-facing slope (SFS) of this canyon differs from the northern-facing slope (NFS) as it receives considerably more solar radiation and consequently forms a more xeric, sparsely vegetated habitat. During the summer, mice living on the two opposite slopes significantly differed in their urine osmolality, which also increased significantly as dietary salinity increased. Offspring of wild-captured mice, born in captivity, and examined during the winter, continued to show a difference in osmoregulatory function depending on the slope of origin. However, they differed from wild-captured mice, as they did not respond to the increase in dietary salinity by increasing the concentration of their urine, but rather by increasing the volume of urine produced. This study shows that A. cahirinus occupying different microhabitats may exhibit differences in their ability to concentrate urine and thus in their ability to withstand xeric conditions. We suggest that they may also differ genetically, as offspring from the NFS and SFS retain physiological differences, but further studies will be needed to confirm this hypothesis