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61.
62.
在著作[1],[2]中指出,根据半球第二区的大气活动中心的研究:西伯利亚高压、极地高压和阿留申低压在寒冷季节中存在着密切的同步相关性关系。并且证明,大气中潮汐或大气外壳的引力变形,显示了年和日的变化,这就形成了预报的基础,该效应表现了行星的特征。引潮力的长周期部分可以扰乱地球高纬度的引力,在大气和海洋所形成的这种现象可以详细分析由这种力的长周期变化的垂直分量所产生的转换部分的重力特征,即具有重力的周期。自然现象起因的相似论述,构成了一种大气过程以及为预报 相似文献
63.
Decades of commercial planting and other anthropogenic processes are posing a threat to the riparian landscapes of the Cauvery river basin, which supports a high floral diversity. Despite this, the habitats in the upstream sections of the River Cauvery are still intact, as they are located in sacred groves. To understand the dynamism of riparian forests exposed to anthropogenic pressures, the upstream stretch of Cauvery extending from Kushalanagara to Talacauvery (~102 km) was categorized into two landscapes: agro ecosystem and sacred (i.e. preserved). The tree species were sampled using belt transects at 5 km intervals and the regeneration status of endemic species assessed using quadrats. A total of 128 species belonging to 47 families, and representing 1,590 individuals, was observed. Amongst them, 65% of unique species were exclusive to sacred landscapes. A rarefaction plot confirmed higher species richness for the sacred compared to the agro ecosystem landscapes, and diversity indices with more evenness in distribution were evident in sacred landscapes. A significant loss of endemic tree species in the agro ecosystem landscapes was found. Overall, this study demonstrates that an intense biotic pressure in terms of plantations and other anthropogenic activities have altered the species composition of the riparian zone in non-sacred areas. A permanent policy implication is required for the conservation of riparian buffers to avoid further ecosystem degradation and loss of biodiversity. 相似文献
64.
Hong Kong has undergone substantial economic transformations and developed into a sophisticated business and financial center in the Asia-Pacific region,since the return of sovereignty to China as a Special Administrative Region under the One Country Two Systems (OCTS) in 1997.This paper discusses and analyzes the industrial structural changes of Hong Kong in recent decades as well as its future challenges and opportunities.The data and finding reveal that even though Hong Kong will face fierce competition from the Mainland’s cities as the rise of China,the important role as a bridge between China and the rest of the world will brace Hong Kong itself under the OCTS for developing into a service hub for business and trade in the Asia-Pacific region. 相似文献
65.
土地是民生之本,发展之基。土地问题是现代工业进程中一个带有全局性、战略性的重大问题。目前,广西工业化、城镇化水平比全国平均水平低很多,"八山一水一分田"的广西要加快推进工业化、城 相似文献
66.
Lagerstatte是指保存丰富或精美化石、因而具有特殊研究价值的化石层.这类地层所含的化石常具有经矿化的生物软体甚至未变实体,从而为古生物的分类学、组织学、形态学、解剖学、生态学、埋藏学等研究提供了极其难得的材料.近年来发现于美国艾奥瓦州的文尼希克化石层,以其特异保存的多门类不常见化石分子为特征,成为目前仅知的中奥陶世Lagerstatte.这一生物群的发现不仅填补了化石记录中的一些空白,也为中奥陶世的生物辐射事件研究领域打开了一个在赤道附近非正常海洋环境中生存的生物群面貌窗口.而且,其中所含的不同类别矿化生物残留,在有机物的分解、置换以及生物成岩作用等研究中具有重要意义.初步研究表明,文尼希克生物群的生活环境与化石保存,可能与陨石撞击事件有关,从而为奥陶纪生物辐射事件的起因町能与太空星体爆裂有关的理论研究,提供了新的验证材料. 相似文献
67.
当2009年元旦来临之际,国务院总理温家宝来到了青岛,看望并慰问广大的干部群众,鼓励大家面对当前的经济困境要坚定信心,迎难而上,创造新业绩。温总理抓住了解决当前中国应对经济衰退问题的核心,抓住了根本。对一个“后发的工业化大国”而言,战胜当下的经济困难,中国缺少的不是“金钱”,而是“人心”。问题的关键在于树立坚定的信心。——题记 相似文献
68.
We propose a unified picture of high magnetic field radio pulsars and magnetars by arguing that they are all rotating high-field neutron stars but that their magnetic axes have different orientations with respect to their rotation axes. In strong magnetic fields where photon splitting suppresses pair creation near the surface, the high-field pulsars can have active inner accelerators while the anomalous X-ray pulsars cannot. This can account for the very different observed emission characteristics of the anomalous X-ray pulsar 1E 2259+586 and the high-field radio pulsar PSR J1814-1744. A predicted consequence of this picture is that radio pulsars having surface magnetic fields greater than about 2x1014 G should not exist. 相似文献
69.
Planetary nebulae (PNe) in the Large Magellanic Cloud (LMC) offer the unique opportunity to study both the population and evolution of low- and intermediate-mass stars, by means of the morphological type of the nebula. Using observations from our LMC PN morphological survey, and including images available in the Hubble Space Telescope Data Archive and published chemical abundances, we find that asymmetry in PNe is strongly correlated with a younger stellar population, as indicated by the abundance of elements that are unaltered by stellar evolution (Ne, Ar, and S). While similar results have been obtained for Galactic PNe, this is the first demonstration of the relationship for extragalactic PNe. We also examine the relation between morphology and abundance of the products of stellar evolution. We found that asymmetric PNe have higher nitrogen and lower carbon abundances than symmetric PNe. Our two main results are broadly consistent with the predictions of stellar evolution if the progenitors of asymmetric PNe have on average larger masses than the progenitors of symmetric PNe. The results bear on the question of formation mechanisms for asymmetric PNe-specifically, that the genesis of PNe structure should relate strongly to the population type, and by inference the mass, of the progenitor star and less strongly on whether the central star is a member of a close binary system. 相似文献
70.
引子:在农地上,个体农户更大的权利,就意味着他更大的反对的能力,阻止的能力,少数决定多数的能力。农民更大的土地权利并非只是某一个农户的更大土地权利,而是所有农户都扩大了土地权利,从而扩大了反对和阻止公共决策的能力,从而也就意味着即使对大多数农户有益,大多数农户有了强烈要求的决策,却可能因为少数甚至个别农户反对而无法实施。——摘自贺雪峰《小农立场》。 相似文献