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针对玉米的作物特性的干旱指数 总被引：3，自引：0，他引：3
目前广泛使用的农业干旱指标如帕尔默干旱严重程度指数和作物水分指数都没有考虑定作物对干旱事件的响应，因此，由ＰＤＳＩ及ＣＭＩ等指数得到的值都不能直接把干旱对作物生产及产量的影响联系起来，该文提出了一个新的干旱指数，它针对某一种作物且考虑了作物特定生长过程中的水分利用，研制作物特性干旱指数（简称ＣＳＤＩ）使用了内由拉斯加州中东部作物报千区８年的资料，并用该ＣＲＤ另外１０年资料，密苏里州东北部ＣＲＤ９年 相似文献
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We examined post-spill trends (1989-1998) of marine bird populations in Prince William Sound (PWS) following the Exxon Valdez oil spill (EVOS) to evaluate recovery of injured taxa. Two criteria were employed. First, we examined population trends of injured taxa only in the oiled area of PWS using regression models. Second, we examined population trends of injured taxa in the oiled area relative to the unoiled area using homogeneity of the slopes tests. We considered a population recovering if there was a positive trend using either criteria. We considered a population not recovering if there was no trend using either criteria or a negative trend in the oiled area. A significant negative trend in the oiled area relative to the unoiled area was considered a continuing and increasing effect. Most taxa for which injury was previously demonstrated were not recovering and some taxa showed evidence of increasing effects nine years after the oil spill. Four taxa (loons Gavia spp, Harlequin Duck Histrionicus histrionicus, Bufflehead Bucephala spp, and North-western Crow Corvus caurinus) showed weak to very weak evidence of recovery. None of these taxa showed positive trends in both winter and summer. Nine taxa (grebes Podiceps spp, cormorants Phalacrocorax spp, Black Oystercatcher Haematopus bachmani, Mew Gull Larus canus, Glaucous-winged Gull Larus glaucescens, terns Sterna spp, murres Uria spp, Pigeon Guillemot Cepphus columba, and murrelets Brachyramphus spp) showed no evidence of recovery during summer or winter. Four taxa (scoters Melanitta spp, mergansers Mergus spp, goldeneyes Bucephala spp, and Black-legged Kittiwaka Rissa tridactyla) showed evidence of continuing, increasing effects. We showed evidence of slow recovery, lack of recovery, and divergent population trends in many taxa which utilize shoreline and nearshore habitats where oil is likely to persist. Potential lingering spill effects and natural variability appear to be acting in concert in delaying recovery of many PWS bird populations. 相似文献
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《海洋地质与第四纪地质》是原地质矿产部海洋地质研究所和地质矿产部第四纪地质研究中心主办的综合性学术期刊，创刊于１９８１年，在国内外地学界具有较高的知名度。对该刊论文作者进行统计分析，有助于了解我国海洋地质科研队伍的现状及发展历史。１《海洋地质与第四纪... 相似文献
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Holt SJ 《Marine pollution bulletin》2007,54(8):1081-1086
It is argued that Japan’s authorities and entrepreneurs involved in whaling and the whale-meat trade have a long-term goal of rebuilding a large and profitable industry of pelagic whaling, particularly in the Southern Hemisphere, in the next 20 years or so. They have made large investments in this enterprise since the so-called moratorium on commercial whaling was adopted by the International Whaling Commission in 1982. These include, but are not confined to, state subsidizing of an expanding and diversifying 20-year programme of commercial whaling under provisions in all relevant international agreements since 1937 that permit unlimited and unilaterally decreed whaling, supposedly for scientific purposes, provided that the commodities from the whales killed are fully utilized. The context of this is the monopoly of technical knowledge, special skills and the market for valuable whale-meat that Japanese enterprises acquired in the post-world war II period, having broken - in 1937 - the strongly defended de facto Anglo-Norwegian monopoly of technology, skills, access to Antarctic whaling grounds and the market for whale-oil that had existed until then. The attraction of ‘scientific whaling’ is not only that it by-passes any internationally agreed catch-limits but that it also circumvents all other rules - many dating fr/om the League of Nations whaling convention of 1931 - regarding protected species, closed areas, killing of juveniles, less inhumane killing methods, etc. The groundwork is being laid to justify that resumed whaling on partially recovered whale stocks will be at the unsustainable levels that will be profitable again. This justification is based on spurious assertions that numerous and hungry whales threaten the world’s fisheries, and that the abundance and possible increase in some whale species is impeding the recovery of other, severely depleted, and potentially more valuable species such as the blue whale. If the scenario presented here is correct it has important implications for attempts by the international community either to bring a negotiated end to commercial whaling or to bring all whaling back under international control, as the international law of the sea requires, and to ensure that any permitted exploitation of recovered whale populations will be sustainable, under a precautionary regime. 相似文献
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We conducted studies to determine if the xenoestrogens Surflan and its active ingredient oryzalin, affect indices of reproductive fitness in medaka (Oryzias latipes). Oryzalin (0.5, 0.25mg/l) or Surflan (2.0 microl/l) and oryzalin (0.5mg/l) significantly increased the mean number of non-fertilized eggs produced by treated females paired with untreated males, or by untreated females paired with treated males. Oryzalin (1.0, 0.5, 0.25mg/l) and Surflan (3.8, 2.0, 1.0 microl/l) significantly affected the time to hatch of eggs from treated females paired with untreated males, and from untreated females paired with treated males. Surflan (3.8, 2.0, 1.0 microl/l) induced intersex lesions in 80-100% of males. Oryzalin-exposed males exhibited a significant increase in the incidence of necrotic spermatids and necrotic spermatogonia, while oryzalin-exposed females had significantly fewer immature oocytes and an increase in the occurrence of hyperplastic ovaries. Our results indicate that Surflan and oryzalin affect both reproduction and gonadal histology in male and female medaka. 相似文献