73 research outputs found
WTO accession, the changing competitiveness of foreign-financed firms and regional development in Guangdong of southern China
This paper investigates the changing competitiveness of foreign-financed manufacturing firms and its implications for regional development in Guangdong province of southern China in the run-up to World Trade Organization (WTO) accession. It is argued that transnational corporations (TNCs) and some competitive, large-scale, locally-funded firms in Guangdong will triumph after WTO accession. The crowding-out process of small and medium sized enterprises (SMEs) in Guangdong will be accelerated in the near future, as they are competing directly with TNCs, and as their competitive advantages are diminishing, due to bureaucratic red tape and the rigorous enforcement of new government policies. Due to close business linkages with local privately-funded firms, the competitiveness and vitality of foreign-financed enterprises will have profound long term effects on the economic development of Guangdong, before and after WTO accession
Phototaxisâ in the absence of light? Locomotory patterns in unionid mussels.
Locomotion in benthic invertebrates can strongly affect habitat selection and ecosystem nutrient cycling. In the case of freshwater mussels, the drivers of locomotion are largely unresolved. Our aim was to assess the influence of light presence and intensity on the locomotory behaviour of freshwater mussels in controlled laboratory experiments. The species investigated in our study were Anodonta anatina and Unio pictorum, two widely distributed mussels in European lentic and lotic inland waters. At low algal concentrations, known to be associated with more frequent locomotory activities, we found that both species moved primarily in the absence of light (72.7% of all movements across experiments). However, the movements of both species were directed towards the light source, resembling a net-positive âphototacticâ response but in the absence of light. The distance to the light source, which was negatively correlated to light intensity, had a positive effect on the distance covered in locomotory activities by A. anatina but not by U. pictorum. Intraspecific variation in shell size had no impact on movement distance, indicating that the energetic costs of movement were not a limiting factor. We suggest that the observed movement towards brighter locations helps to enhance food quantity and quality, whilst movement in darkness mitigates predation risks
Mechanisms of conversion of xanthine dehydrogenase to xanthine oxidase in ischemic rat liver and kidney
The HermansâRasson test as a powerful alternative to the Rayleigh test for circular statistics in biology
A putative mechanism for magnetoreception by electromagnetic induction in the pigeon inner ear
A diverse array of vertebrate species employs the Earth's magnetic field to assist navigation. Despite compelling behavioral evidence that a magnetic sense exists, the location of the primary sensory cells and the underlying molecular mechanisms remain unknown [1]. To date, most research has focused on a light-dependent radical-pair-based concept and a system that is proposed to rely on biogenic magnetite (Fe3O4) [2, 3]. Here, we explore an overlooked hypothesis that predicts that animals detect magnetic fields by electromagnetic induction within the semicircular canals of the inner ear [4]. Employing an assay that relies on the neuronal activity marker C-FOS, we confirm that magnetic exposure results in activation of the caudal vestibular nuclei in pigeons that is independent of light [5]. We show experimentally and by physical calculations that magnetic stimulation can induce electric fields in the pigeon semicircular canals that are within the physiological range of known electroreceptive systems. Drawing on this finding, we report the presence of a splice isoform of a voltage-gated calcium channel (CaV1.3) in the pigeon inner ear that has been shown to mediate electroreception in skates and sharks [6]. We propose that pigeons detect magnetic fields by electromagnetic induction within the semicircular canals that is dependent on the presence of apically located voltage-gated cation channels in a population of electrosensory hair cells
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