361 research outputs found

    South Africa's regional political economy: A critical analysis of reform strategy in the 1980s.

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    African Studies Seminar series. Paper presented October, 1985Since the late 1970s the apartheid state has faced a sustained and deepening crisis of legitimation.(1) This crisis has been exacerbated by the attempt, and failure, to implement the post- Soweto 'Total Strategy' reforms - reforms which, in the case of the black people of South Africa, left the territorial and political basis of grand apartheid intact. Since the end of the short-lived boom of 1979-82, the crisis of political legitimacy has been amplified by the slide into economic depression, and the scope for concessionary economic reforms has been drastically curtailed. For some time, the state has been caught up with the immediate threat of escalating opposition in the townships, the symptoms of the deepening economic crisis and spreading international hostility to apartheid. But while this has been happening, elements within the ruling groups, both inside and outside the state, have for some time been attempting to map out a longer-term strategic offensive aimed at defusing political conflict and re-structuring the economy. Faced with a shrinking material basis for concessionary economic reform and growing mobilisation behind the demand for the extension of political rights, the country's ruling groups have begun the search for political solutions to the crisis. The schemes now being formulated take as their starting point the ultimate inevitability of political incorporation of black people into a single national state in South Africa. They aim to meet this in ways that ensure that real power remains in the hands of the ruling classes. The move towards political reforms for black people has gone beyond the stage of discussion and planning in certain areas of policy. Already an important pillar of the emerging strategy has gained expression in local government measures passed in 1985. (2) However much of what is planned has so far only appeared in general policy statements. It is also evident that important facets of the strategy are still in the stage of formulation or are deliberately being held back for the moment. The fluidity of political conditions in South Africa is such that state strategy is the subject matter of open debate and contestation, and is unusually susceptible to official reconsideration and reformulation. Nevertheless we believe it is possible to identify the major contours of an emerging strategy which has been pursued with increasing determination by reformers within the commanding heights of the state since late in 1984. This offensive is significant in that it goes well beyond the policy package associated with the Wiehahn and Riekert Commission reports, the Koornhof Bills, the new constitution, and the confederation of ethnic states - it goes beyond the 'Total Strategy' formulated by PW Botha in the late 1970s. (3) In contrast to these policies, it is based on an abandonment of the political and territorial premises of apartheid, though not necessarily of race or ethnicity, and envisages the eventual reincorporation of the bantustans into a single national South African state. The manner in which this will occur is by no means clear or decided. However, this process of political re-integration of the bantustans is intended ultimately to result in the reorganisation of the territorial basis of South Africa's economic and political system. Central to the reform strategy is the conception that the present provinces and bantustans will be superceded by metropolitan and regionally-based administrative structures through a process of merging, absorption and crosscutting of present geographical boundaries. It is this geographic outcome of the intended reform strategy that has led us to describe the complex of evolving measures as the state's regional strategy. The aim of this article is to describe, anticipate and critically analyse the outlines of the emerging regional strategy. Its three major components are new controls on labour movement and settlement, regional development policies (notably industrial decentralisation), and local and second tier government reforms and corresponding constitutional changes. We examine each of these three components and their interconnections. A central issue taken up in the paper is the debate over the possible construction of a federal system in South Africa. We examine major alternative conceptions of the basis of federalism - geographic and ethnic - and show how they correspond to or contradict other plans to divide South Africa into metropolitan and wider planning and administrative regions. The paper ends with an assessment and critical analysis of the regional strategy

    Copper-Sensitive Mutant of Arabidopsis thaliana

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    A synthesis of atmospheric mercury depletion event chemistry in the atmosphere and snow

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    It was discovered in 1995 that, during the spring time, unexpectedly low concentrations of gaseous elemental mercury (GEM) occurred in the Arctic air. This was surprising for a pollutant known to have a long residence time in the atmosphere; however conditions appeared to exist in the Arctic that promoted this depletion of mercury (Hg). This phenomenon is termed atmospheric mercury depletion events (AMDEs) and its discovery has revolutionized our understanding of the cycling of Hg in Polar Regions while stimulating a significant amount of research to understand its impact to this fragile ecosystem. Shortly after the discovery was made in Canada, AMDEs were confirmed to occur throughout the Arctic, sub-Artic and Antarctic coasts. It is now known that, through a series of photochemically initiated reactions involving halogens, GEM is converted to a more reactive species and is subsequently associated to particles in the air and/or deposited to the polar environment. AMDEs are a means by which Hg is transferred from the atmosphere to the environment that was previously unknown. In this article we review Hg research taken place in Polar Regions pertaining to AMDEs, the methods used to collect Hg in different environmental media, research results of the current understanding of AMDEs from field, laboratory and modeling work, how Hg cycles around the environment after AMDEs, gaps in our current knowledge and the future impacts that AMDEs may have on polar environments. The research presented has shown that while considerable improvements in methodology to measure Hg have been made but the main limitation remains knowing the speciation of Hg in the various media. The processes that drive AMDEs and how they occur are discussed. As well, the role that the snow pack and the sea ice play in the cycling of Hg is presented. It has been found that deposition of Hg from AMDEs occurs at marine coasts and not far inland and that a fraction of the deposited Hg does not remain in the same form in the snow. Kinetic studies undertaken have demonstrated that bromine is the major oxidant depleting Hg in the atmosphere. Modeling results demonstrate that there is a significant deposition of Hg to Polar Regions as a result of AMDEs. Models have also shown that Hg is readily transported to the Arctic from source regions, at times during springtime when this environment is actively transforming Hg from the atmosphere to the snow and ice surfaces. The presence of significant amounts of methyl Hg in snow in the Arctic surrounding AMDEs is important because this species is the link between the environment and impacts to wildlife and humans. Further, much work on methylation and demethylation processes has occurred but these processes are not yet fully understood. Recent changes in the climate and sea ice cover in Polar Regions are likely to have strong effects on the cycling of Hg in this environment; however more research is needed to understand Hg processes in order to formulate meaningful predictions of these changes

    Suppression of Chlorella vulgaris Growth by Cadmium, Lead, and Copper Stress and Its Restoration by Endogenous Brassinolide

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    Brassinosteroids play a significant role in the amelioration of various abiotic and biotic stresses. In order to elaborate their roles in plants subjected to heavy metals stress, Chlorella vulgaris cultures treated with 10−8 M brassinolide (BL) were exposed to 10−6–10−4 M heavy metals (cadmium, lead and copper) application. Under heavy metals stress, the growth and chemical composition (chlorophyll, monosaccharides, and protein content) have been decreased during the first 48 h of cultivation. The inhibitory effect of heavy metals on C. vulgaris cultures was arranged in the following order: copper > lead > cadmium. C. vulgaris cultures treated with BL in the absence or presence of heavy metals showed no differences in the endogenous level of BL. On the other hand, treatment with heavy metals results in BL level very similar to that of control cell cultures. These results suggest that the activation of brassinosteroids biosynthesis, via an increase of endogenous BL, is not essential for the growth and development of C. vulgaris cells in response to heavy metals stress. Simultaneously, BL enhanced the content of indole-3-acetic acid, zeatin, and abscisic acid in cultures treated with heavy metals. Levels per cell of chlorophylls, protein, and monosaccharides are all increased by BL treatment when compared to nontreated control cells. Application of BL to C. vulgaris cultures reduced the accumulation of heavy metals stress on growth, prevented chlorophyll, monosaccharides, and protein loss, and increased phytochelatins content. The arrested growth of C. vulgaris cells treated with heavy metals was restored by the coapplication of BL. It suggested that BL overcame the inhibitory effect of heavy metals. From these results, it can be concluded that BL plays the positive role in the alleviation of heavy metals stress

    Radar observations of winds, waves and tides in the mesosphere and lower thermosphere over South Georgia island (54◦S, 36◦W) and comparison to WACCM simulations [in review]

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    The mesosphere and lower thermosphere (MLT) is a dynamic layer of the earth’s atmosphere. This region marks the interface at which neutral atmosphere dynamics begin to influence the ionosphere and space weather. However, our understanding of this region and our ability to accurately simulate it in global circulation models (GCMs) is limited by a lack of observations, especially in remote locations. To this end, a meteor radar was deployed on the remote mountainous island of South Georgia (54° S, 36° W) in the Southern Ocean from 2016 to 2020. The goal of this study is to use these new measurements to characterise the fundamental dynamics of the MLT above South Georgia including large-scale winds, solar tides, planetary waves (PWs) and mesoscale gravity waves (GWs). We first present an improved method for time-height localisation of radar wind measurements and characterise the large-scale MLT winds. We then explore the amplitudes and phases of the diurnal (24 h), semidiurnal (12 h) and terdiurnal (8 h) solar tides at this latitude. We also explore PW activity and find very large amplitudes up to 30 ms−1 for the quasi-2 day wave in summer and show that the dominant modes of the quasi-5, 10 and 16 day waves are westward W1 and W2. We investigate wind variance due to GWs in the MLT and use a new method to show an east-west tendency of GW variance of up to 20 % during summer and a weaker north-south tendency of 0–5 % during winter. This is contrary to the expected tendency of GW directions in the winter stratosphere below, which is a strong suggestion of secondary GW (2GW) observations in the MLT. Lastly, comparison of radar winds to a climatological Whole Atmosphere Community Climate Model (WACCM) simulation reveals a simulated summertime mesopause and zonal wind shear that occur at altitudes around 10 km lower than observed, and southward winds during winter above 90 km altitude in the model that are not seen in observations. Further, wintertime zonal winds above 85 km altitude are eastward in radar observations but in WACCM they are found to weaken and reverse to westward. Recent studies have linked this discrepancy to the impact of 2GWs on the residual circulation which are not included in WACCM. These measurements therefore provide vital constraints that can guide the development of GCMs as they extend upwards into this important region of the atmosphere

    Colocalization of connexin 36 and corticotropin-releasing hormone in the mouse brain

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    <p>Abstract</p> <p>Background</p> <p>Gap junction proteins, connexins, are expressed in most endocrine and exocrine glands in the body and are at least in some glands crucial for the hormonal secretion. To what extent connexins are expressed in neurons releasing hormones or neuropeptides from or within the central nervous system is, however, unknown. Previous studies provide indirect evidence for gap junction coupling between subsets of neuropeptide-containing neurons in the paraventricular nucleus (PVN) of the hypothalamus. Here we employ double labeling and retrograde tracing methods to investigate to what extent neuroendocrine and neuropeptide-containing neurons of the hypothalamus and brainstem express the neuronal gap junction protein connexin 36.</p> <p>Results</p> <p>Western blot analysis showed that connexin 36 is expressed in the PVN. In bacterial artificial chromosome transgenic mice, which specifically express the reporter gene Enhanced Green Fluorescent Protein (EGFP) under the control of the connexin 36 gene promoter, EGFP expression was detected in magnocellular (neuroendocrine) and in parvocellular neurons of the PVN. Although no EGFP/connexin36 expression was seen in neurons containing oxytocin or vasopressin, EGFP/connexin36 was found in subsets of PVN neurons containing corticotropin-releasing hormone (CRH), and in somatostatin neurons located along the third ventricle. Moreover, CRH neurons in brainstem areas, including the lateral parabrachial nucleus, also expressed EGFP/connexin 36.</p> <p>Conclusion</p> <p>Our data indicate that connexin 36 is expressed in subsets of neuroendocrine and CRH neurons in specific nuclei of the hypothalamus and brainstem.</p

    Redox states of glutathione and ascorbate in root tips of poplar (Populus tremula×P. alba) depend on phloem transport from the shoot to the roots

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    Glutathione (GSH) and ascorbate (ASC) are important antioxidants that are involved in stress defence and cell proliferation of meristematic root cells. In principle, synthesis of ASC and GSH in the roots as well as ASC and GSH transport from the shoot to the roots by phloem mass flow is possible. However, it is not yet known whether the ASC and/or the GSH level in roots depends on the supply from the shoot. This was analysed by feeding mature leaves with [14C]ASC or [35S]GSH and subsequent detection of the radiolabel in different root fractions. Quantitative dependency of root ASC and GSH on shoot-derived ASC and GSH was investigated with poplar (Populus tremula×P. alba) trees interrupted in phloem transport. [35S]GSH is transported from mature leaves to the root tips, but is withdrawn from the phloem along the entire transport path. When phloem transport was interrupted, the GSH content in root tips halved within 3 d. [14C]ASC is also transported from mature leaves to the root tips but, in contrast to GSH, ASC is not removed from the phloem along the transport path. Accordingly, ASC accumulates in root tips. Interruption of phloem transport disturbed the level and the ASC redox state within the entire root system. Diminished total ASC levels were attributed mainly to a decline of dehydroascorbate (DHA). As the redox state of ASC is of particular significance for root growth and development, it is concluded that phloem transport of ASC may constitute a shoot to root signal to coordinate growth and development at the whole plant level
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