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121.
Long-term monitoring data show that hard coral cover on the Great Barrier Reef (GBR) has reduced by >70 % over the past century. Although authorities and many marine scientists were in denial for many years, it is now widely accepted that this reduction is largely attributable to the chronic state of eutrophication that exists throughout most of the GBR. Some reefs in the far northern GBR where the annual mean chlorophyll a (Chl a) is in the lower range of the proposed Eutrophication Threshold Concentration for Chl a (~0.2–0.3 mg m−3) show little or no evidence of degradation over the past century. However, the available evidence suggests that coral diseases and the crown-of-thorns starfish will proliferate in such waters and hence the mandated eutrophication Trigger values for Chl a (~0.4–0.45 mg m−3) will need to be decreased to ~0.2 mg m−3 for sustaining coral reef communities. 相似文献
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Lindsey Allan 《黑龙江环境通报》2010,30(7):639-643
The ability to examine the structure of the fetal heart in real-time started over 30 years ago now. The field has seen very great advances since then, both in terms of technical improvements in ultrasound equipment and in dissemination of operator skills. A great deal has been learnt about normal cardiac function in the human fetus throughout gestation and how it is affected by pathologies of pregnancy. There is increasing recognition of abnormal heart structure during routine obstetric scanning, allowing referral for specialist diagnosis and counselling. It is now possible to make accurate diagnosis of cardiac malformations as early as 12 weeks of gestation. Early diagnosis of a major cardiac malformation in the fetus can provide the parents with a comprehensive prognosis, enabling them to make the most informed choice about the management of the pregnancy. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Thermal treatments of five different types of non-ferrous metallurgical wastes, under a controlled atmosphere, were carried out at temperatures lower than 800°C for the separation of their toxic compounds and the concentration of valuable metals in the treatments residues. The best results were obtained by the treatments in air or hydrogen, or both successively. Simple treatments, using air or hydrogen, of three samples allowed the elimination of more than 95% of their toxic elements and almost doubled their valuable metals concentration. For the rest of the samples, a combined treatment was necessary for their efficient decontamination. In this case, the valuable metals content in the treatment's residue was increased to a reasonable value. Most of the solids issuing from these treatments can be recycled in current non-ferrous metallurgical processes. 相似文献
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A.H. El‐Sebae M.E. Abdel‐Ghanv D. Shalloway M.M. Abou Zeid J. Blancato M.A. Saleh 《Journal of environmental science and health. Part. B》2013,48(6):763-777
Abstract Phosphorylation is an indispensable process for energy and signal transduction in biological systems. AlCl3 at 10 nM to 10 uM range activated in‐vitro [γ‐32P)ATP phosphorylation of the brain (tau) T protein in both normal human or E.coli expressed T forms; in the presence of the kinases P34, PKP, and PKC. However, higher concentrations of ALCl3 inhibited the T phosphorylation with P34, PKP, and PKC to a maximum at 1 mM level. AlCl3 at 100 uM to 500 uM range induced non‐enzymatic phosphorylation of T with γ‐ATP, γ‐GTP, and α‐GTP. AlCl3 activated histone phosphorylation by P34 in a similar pattern. The hyperphosphorylation of T by Al3+ was accompanied by molecular shift and mobility retardation in SDS‐PAGE. This may demonstrate the mechanism of the longterm neurological effect of Al3+ in human brain leading to the formation of the neurofibrillary tangles related to Alzeheimer's disease. 相似文献
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The resource curse 总被引:7,自引:0,他引:7
Countries that possess rich mineral deposits, it is widely assumed, are fortunate. Such deposits are assets, part of a country's natural capital. Mining is the key that converts dormant mineral wealth into schools, homes, ports, and other forms of capital that directly contribute to economic development. Over the past two decades, however, a more negative view of mining has emerged that questions the positive relationship between mineral extraction and economic development. The impetus for the alternative view came from empirical studies suggesting that countries where mining is important have not grown as rapidly as other countries. More recent studies have explored the possible reasons behind the disappointing performance of many mineral producing countries. While the central point of contention between the conventional and alternative views — namely, whether or not mining usually promotes economic development — remains unresolved, there is widespread agreement that rich mineral deposits provide developing countries with opportunities, which in some instances have been used wisely to promote development, and in other instances have been misused, hurting development. The consensus on this issue is important, for it means that one uniform policy toward all mining in the developing world is not desirable, despite the recent suggestions by some to the contrary. The appropriate public policy question is not should we or should we not promote mining in the developing countries, but rather where should we encourage it and how can we ensure that it contributes as much as possible to economic development and poverty alleviation. 相似文献
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职业病危害及经济损失 总被引:1,自引:1,他引:1
夏维发 《中国安全科学学报》1994,4(2):47-52
我国工业职业病危害严重,造成的经济损失巨大,约占年国民经济总产值的2.5%以上,加强对职业病危害的预防、控制,以减少损失十分必要。为保证我国经济建设的顺利进行,必须完善立法,用经济手段强化对职业病的预防、监控和管理。 相似文献