59 research outputs found
Are Labour Markets Necessarily Local? Spatiality, Segmentation and Scale
This paper draws on recent debates about scale to approach the geography of labour markets from a dynamic perspective sensitive to the spatiality and scale of labour market
restructuring. Its exploration of labour market reconfigurations after the collapse of a major firm (Ansett Airlines) raises questions about geography’s faith in the inherently ‘local’ constitution of labour markets. Through an examination of the job reallocation process after redundancy, the paper suggests that multiple labour markets use and articulate scale in different ways. It argues that labour market rescaling processes are enacted at the critical moment of recruitment, where social networks, personal aspirations and employer preferences combine to shape workers’ destinations
Thermal plasticity of mitochondria:a latitudinal comparison between Southern Ocean molluscs
Mitochondrial volume density (Vv((mt,f))), cristae surface density (Sv((im,mt))), cristae surface area (Sv((im,f))) and citrate synthase (CS) activity were analysed as indicators of thermal acclimation in foot muscle of the limpet, Nacella concinna, and the clam, Laternula elliptica, collected from 4 locations within the Southern Ocean, South Georgia (54 degrees S, N. concinna only), Signy (60 degrees S), Jubany (L. elliptica only -62 degrees S) and Rothera (67 degrees S). Animals were acclimated to 0.0 degrees C whilst a sub-set of N. concinna (South Georgia, Signy and Rothera) and L. elliptica (Rothera) were acclimated to 3.0 degrees C. At 0.0 degrees C N. concinna had higher Vv((mt,f)), Sv((im,mt)), Sv((im,f)) and muscle fibre specific CS activity than L. elliptica which correlated with the more active life style of N. concinna. However, mitochondrial density was very low, 1-2% in both species, suggesting that low temperature compensation of mitochondrial density is not a universal evolutionary response of Antarctic marine ectotherms. Both Sv((im,mt)) and Sv((im,f)) were reduced by warm acclimation of N. concinna. South Georgia N. concinna maintained muscle fibre specific CS activity after acclimation, in contrast to N. concinna from Rothera and Signy and L. elliptica from Rothera, indicating that they have the physiological plasticity to respond to their warmer, more variable thermal environment
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Small-scale interactions between prions Pachyptila spp. and their zooplankton prey at an inshore site near Bird Island, South Georgia
We investigated the relationship between surface-foraging prions Pachyptila spp. and their zooplankton prey by comparing counts of foraging birds with near-surface concentrations of zooplankton from net samples. Zooplankton abundance was assessed by employing a new design of sampler that combined a frame net with a pump at the cod-end and which was deployed at the sea surface. Six transects using the sampler with concurrent bird observations were made over a short stretch of Stewart Strait near Bird Island, South Georgia. Concentrations of a variety of zooplankton species occurred patchily along each transect. Peak numbers of prions were recorded consistently towards the southern end of each transect. These peaks coincided with peaks in zooplankton numbers, but with different prey species predominant on different occasions. Comparison of the distribution of foraging and sitting birds with the presence or absence of zooplankton peaks, after pooling zooplankton species into 2 broad classes, showed that birds were consistently observed over copepod maxima, but were not found to be associated with aggregations of larger zooplankton more often than expected by chanc
Retinoic acid causes the development of feathers in the scale-forming integument of the chick embryo
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