Spermatogenesis and plasma testosterone levels in Western Australian burrowing desert frogs, Cyclorana platycephala, Cyclorana maini, and Neobatrachus sutor, during aestivation.

Changes in testis size, histological status, and plasma levels of testosterone were monitored for males of three species of Western Australian desert frogs, Cyclorana maini, Cyclorana platycephala, and Neobatrachus sutor during aestivation. The frogs were induced to burrow and form cocoons soon after their capture and then disinterred at intervals in order to monitor changes in reproductive activity of the testes. All stages of spermatogenesis were evident in active frogs, which were collected a few days following rain from breeding choruses.

Ventilatory physiology of the numbat (Myrmecobius fasciatus).

This study examines the ventilatory physiology of the numbat (Myrmecobius fasciatus), a small to medium-sized (550 g) termitivorous marsupial. Ventilatory parameters at thermoneutrality reflect the slightly low (83% of predicted) basal metabolic rate of the numbat, with ventilation frequency (fR; 30.6+/-3.

Field metabolic rate and water turnover of the numbat (Myrmecobius fasciatus).

The numbat (Myrmecobius fasciatus) is a diurnal and exclusively termitivorous marsupial. This study examines interrelationships between diet, metabolic rate and water turnover for wild, free-living numbats. The numbats (488+/-20.

Biophysical properties of the pelt of a diurnal marsupial, the numbat (Myrmecobius fasciatus), and its role in thermoregulation.

Numbats are unusual marsupials in being exclusively diurnal and termitivorous. They have a sparse (1921 hairs cm(-2)) and shallow (1.19 mm) pelt compared with other marsupials.

Thermoregulatory physiology of the Crested Pigeon Ocyphaps lophotes and the Brush Bronzewing Phaps elegans.

The metabolic physiology of the Crested Pigeon (Ocyphaps lophotes) and the Brush Bronzewing (Phaps elegans) is generally similar to that expected for birds of their size, but the Crested Pigeon has a number of characteristics which would aid survival in hot and dry regions. Body temperature increased similarly for the Crested Pigeon (from 38.8 degrees C to 41.

X-ray tomographic imaging of Ti/SiC composites.

In this paper, high-resolution tomographic synchrotron X-ray imaging is applied to study the occurrence and evolution of damage in Ti-6Al-4V/SCS6 SiC fibre composite materials. Three composite morphologies of increasing complexity have been studied, namely single fibre, single-ply and multi-ply composites. The single fibre composite was strained to full fibre fragmentation and the progressive introduction of damage monitored.

Metabolic and thermal physiology of pigeons and doves.

Pigeons and doves (Columbidae) are an interesting group to examine for physiological adaptations to climate and diet because this cosmopolitan family comprises more than 300 species that are mostly granivores, although some are specialized frugivores. We determined allometric and phylogenetic effects on body temperature (T(b)), basal metabolic rate (BMR; J h(-1)), and wet thermal conductance (C(wet); J h(-1) C(-1)), and we examined mass (M) and phylogenetically corrected residuals for further effects of climate, diet, and landmass size (mainland or island). Independent contrasts, correlograms, autoregression, and phylogenetic eigenvector regression (PVR) were used to examine phylogenetically related effects.

Pathways regulating Na+/Ca2+ exchanger expression in the heart.

The Na(+)/Ca(2+) exchanger (NCX1) is regulated at the transcriptional level in cardiac hypertrophy, ischemia, and failure. Following pressure overload, activation of MAPKs coincides with the kinetics of NCX1 gene upregulation in adult cardiocytes. Using adenoviral gene delivery, we begin to identify the molecular pathways responsible for upregulation of the exchanger gene.

Dracunculiasis eradication: and now, Sudan.

This paper summarizes the status of the global dracunculiasis eradication campaign as of early 2002. Of the 20 countries that were endemic when the campaign began, seven have already interrupted transmission, four countries reported less than 100 cases each, and only five countries reported more than 1,000 cases each in 2001. Only 14,000 cases remained outside Sudan in 2001.

Metabolic physiology of the numbat (Myrmecobius fasciatus).

The numbat (Myrmecobius fasciatus) is unique amongst marsupials as it is exclusively diurnal, feeds only on termites and is semi-fossorial. This study examines the thermal and metabolic physiology of the numbat to determine if its physiology reflects its phylogeny, diet and semi-fossorial habit. Numbats (mean adult body mass 552 g) were able to regulate body temperature at ambient temperatures of 15-30 degrees C, with a body temperature at thermoneutrality (30 degrees C) of 34.

In vivo downregulation of protein synthesis in the snail Helix apersa during estivation.

Protein synthesis is downregulated during metabolic depression in a number of systems where the metabolic depression is effected by obvious extrinsic cues. The metabolic depression of the estivating land snail Helix apersa occurs in the absence of any obvious physiological stress and has an intrinsic component independent of temperature, pH, O(2) status, or osmolality. We show that this metabolic depression is accompanied by a downregulation of protein synthesis in vivo.

Winning employee-retention strategies for today's healthcare organizations.

Employees today want more out of a job than a big salary. Workers' expectations have shifted over the past few decades. Employers need to recognize five key changes in workers' expectations, namely that they want to lead balanced lives, enjoy partnership with their employers, receive opportunities for personal and professional growth, be able to make a meaningful contribution to the world through their work, and experience opportunities to socialize at work.

Indicator to predict the movement of phosphorus from soil to subsurface flow.

The movement of phosphorus (P) in subsurface flow can contribute to losses from agricultural land. This study aims to identify a soil P threshold above which P loss is likely to accelerate as a function of soil and management type. Lysimeters (25 cm i.

Water content, body weight and acid mucopolysaccharides, hyaluronidase and beta-glucuronidase in response to aestivation in Australian desert frogs.

This study investigates the effects of aestivation on body water content, body mass, acid mucopolysaccharide (AMPS) and some of its degrading enzymes in different tissues for some Australian desert frogs. The AMPS component of the liver, kidney, skin and cocoon alter during aestivation to help retain water, which is unchanged in most tissues of all frog species, and to protect the frogs from desiccation during extended periods of aestivation. Hepatic AMPS was unaltered in Cyclorana maini, C.

Aerial and aquatic respiration of the Australian desert goby, Chlamydogobius eremius.

Physiological, anatomical and behavioural adaptations enable the Australian desert goby, Chlamydogobius eremius, to live in mound springs and temporary aquatic habitats surrounding the south-eastern rim of the Lake Eyre drainage basin in the harsh inland of Australia. This study describes the desert goby's respiratory and metabolic responses to hypoxic conditions and its use of buccal air bubbles for gas exchange at the water surface. Oxygen consumption for C.

Agricultural nutrient inputs to rivers and groundwaters in the UK: policy, environmental management and research needs.

Losses of nitrogen (N) and phosphorus (P) in land run-off and drainage from agricultural land can impair river water quality and may pose a potential health hazard. Losses of P are up to an order of magnitude smaller than those of N, but may be more significant with respect to freshwater eutrophication. At the field scale, research suggests that rates of nutrient loss are sensitive to both nutrient and land management, in particular, where nutrient inputs continuously exceed production requirements and where farming methods increase land vulnerability to run-off and erosion.

Re-evaluation of the allometry of wet thermal conductance for birds.

Wet thermal conductance is an important thermoregulatory parameter for birds and mammals. It is generally calculated as C(wet) (ml O2 g(-1) h(-1) degrees C(-1)) = VO2/(T(b)-T(a)), where VO2 is metabolic rate measured in ml O2 g(-1) h(-1), T(b) is body and T(a) is ambient temperature measured in degrees C. Minimum C(wet) is measured at T(a) at or below the lower critical temperature (T(lc)) of the thermoneutral zone, and is strongly influenced by time of day (rest or activity phase) and body mass [J.

Oxygen consumption, carbon dioxide excretion and respiratory quotient of larval lampreys (Mordacia mordax) in air.

The standard rates of O2 consumption of larval Mordacia mordax (weight range 1.3-2.3 g), after these ammocetes had been in humidified air for 18 hr, were 26.

The role of protein synthesis during metabolic depression in the Australian desert frog Neobatrachus centralis.

Little is known about the role of energy consuming processes during metabolic depression. We have shown that aestivation in the Australian desert frog Neobatrachus centralis is accompanied by an in vivo metabolic depression of 77%. Using an in vitro liver slice preparation, we have measured an in vitro metabolic depression in liver of 55%, with a concomitant 67% decrease in the rate of protein synthesis.

Protein synthesis in the liver of Bufo marinus: cost and contribution to oxygen consumption.

While many estimates of the contribution of protein synthesis to metabolic rate exist for a variety of animals, most rely on theoretical costs of protein synthesis. The limitations of this approach are that theoretical costs depend upon variable estimates of ATP cost per peptide bond. In addition, they do not take into account the fact that there are protein-specific pre- and post-translational costs.