SUMMARY1. Activation of left atrial receptors by distension of balloons at the pulmonary vein-atrial junctions caused an increase in the cardiac sympathetic nerve activity, a decrease in the renal sympathetic nerve activity, and no change in the lumbar and splenic sympathetic nerve activity.2. The cardiac and renal nerve responses to balloon distension were abolished by vagal blockade in the neck.3. The results provide additional evidence that the reflex increase in the heart rate following stimulation of the left atrial receptors is mediated by selective activation of cardiac sympathetic nerve fibres.4. The inhibitory effect of atrial receptor activation on the renal sympathetic nerve activity suggests that a neural factor, possibly involving renal haemodynamics, may be a component of the diuretic response to the activation of the left atrial receptors.5. The results provide further evidence for the selective nature of the pattern of reflex responses to left atrial receptor activation and show for the first time a directionally fractionated response from sympathetic efferent neurones.

Abstract:Hydrological connectivity between floodplain wetlands and rivers is one of the principal driving mechanisms for the diversity, productivity and interactions of the major biota in river-floodplain systems. This article describes a method of quantifying floodinduced overbank connectivity using a hydrodynamic model (MIKE 21) to calculate the timing, the duration and the spatial extent of the connections between several floodplain wetlands and rivers in the Tully-Murray catchment, north Queensland, Australia. Areal photogrammetry and field surveyed stream cross data were used to reproduce floodplain topography and rivers in the model. Laser altimetry (LiDAR)-derived fine resolution elevation data, for the central floodplain, were added to the topography model to improve the resolution of key features including wetlands, flow pathways and natural and artificial flow barriers. The hydrodynamic model was calibrated using a combination of in-stream and floodplain gauge records. A range of offstream wetlands including natural and artificial, small and large were investigated for their connectivity with two main rivers (Tully and Murray) flowing over the floodplain for flood events of 1-, 20-and 50-year recurrence intervals. The duration of the connection of individual wetlands varied from 1 to 12 days, depending on flood magnitude and location in the floodplain, with some wetlands only connected during large floods. All of the wetlands studied were connected to the Tully River for shorter periods than they were to the Murray River because of the higher bank heights and levees on the Tully River and wetland proximity to the Murray River. Other than hydrology, land relief, riverbank elevation and levee banks along the river were found key factors controlling the degree of connectivity. These variations in wetland connectivity could have important implications for aquatic biota that move between rivers and off-stream habitats during floods.

Compared with men, women experienced longer delays at various stages of the clinical process of help seeking for TB. This warrants appropriate measures to improve the situation.

We investigated the biophysical environment, invertebrate fauna and ecosystem health of lagoons on the Tully-Murray floodplain in the Queensland Wet Tropics bioregion. These wetlands are biologically rich but have declined in area and condition with agricultural development and are poorly protected, despite being located between two World Heritage areas. Lagoons varied in size, habitats and water quality, with increasing signatures of agriculture (e.g. elevated nutrient concentrations) from the upper to lower floodplain. Zooplankton were abundant, but not diverse, and correlated variously with environmental variables, so were not useful in assessing lagoon condition. Benthic macroinvertebrates were abundant and diverse and correlated strongly with riparian condition, habitats, water quality and degree of agriculture in the catchment, but gradients in assemblage structure were not strong because the flow regime, with multiple annual floods, maintains higher water quality than in some tropical systems. The absence of pristine reference lagoons and the limited availability of replicate sites hamper the development of monitoring systems. Nevertheless, we show that appropriate sampling, analysis and knowledge of comparable systems allow inferences to be drawn regarding ecological condition. This is important because environmental managers need best available and timely advice whatever the opportunities for rigorous study design.