共查询到20条相似文献，搜索用时 93 毫秒
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宁波出口盆栽植物星天牛综合防控措施研究 总被引：3，自引：1，他引：2
[目的]应对欧盟对星天牛实施的严格检疫措施,为我国红枫等盆栽植物的出口安全提供技术支持。[方法]在综合分析欧盟有关法规的基础上,结合星天牛生物学特性、药剂熏蒸和浸泡等防治研究,提出了出口盆栽植物星天牛的综合防控措施。[结果]采用40%辛硫磷＋80%敌敌畏乳油500倍液浸泡处理36 h或25 g/L溴氰菊酯500倍液浸泡处理48 h可完全杀死苗木中的星天牛幼虫。[结论]在物理隔离基础上,结合盆栽植物生产过程控制,并配合一定的化学防治措施,可有效防控星天牛,这对有关盆栽植物出口企业有较好的指导作用。 相似文献
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Atmospheric radiocarbon calibration to 45,000 yr B.P.: late glacial fluctuations and cosmogenic isotope production 总被引：1，自引：0，他引：1
More than 250 carbon-14 accelerator mass spectrometry dates of terrestrial macrofossils from annually laminated sediments from Lake Suigetsu (Japan) provide a first atmospheric calibration for almost the total range of the radiocarbon method (45,000 years before the present). The results confirm the (recently revised) floating German pine chronology and are consistent with data from European and marine varved sediments, and combined uranium-thorium and carbon-14 dating of corals up to the Last Glacial Maximum. The data during the Glacial show large fluctuations in the atmospheric carbon-14 content, related to changes in global environment and in cosmogenic isotope production. 相似文献
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[目的]评价欧洲土壤环境地球化学特征,为改善和调控生态环境、制订社会经济可持续发展规划提供决策依据。[方法]采用多重分形方法、综合指数法,结合欧洲地质状况,对欧洲表层和深层土壤中As、Co、Cr、Cu、Ni、Pb、Zn 7种重金属元素地球化学数据进行统计分析,探讨了重金属在表层和深层土壤中的分布规律,并对其进行环境地球化学特征评价。[结果]重金属元素在欧洲表层和深层土壤中的分布具有多重分形分布特征,且各元素含量在多重分形频谱曲线上均显示连续的多重分形分布,并受各国的经济社会发展和矿产开采等情况影响,导致重金属在各国家、地区的污染程度不同。欧洲土壤重金属污染程度为清洁至中污染,尤以巴尔干半岛和意大利北部重金属污染严重,而其他地区重金属含量与世界土壤均值相当,且略低于中国土壤均值,各元素综合污染指数从大到小依次为Ni、As、Co、Cr、Pb、Zn、Cu。[结论]该研究不仅为土壤质量评价,更能为保护人类健康制订有效措施提供重要信息。 相似文献
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秋园位于板浦古镇,为民国时期盐业界名人缪秋杰所造之公园,抗日时期毁于战火。该园基址为平地,后依其时淮北盐区地势由人工理水堆山而成,又间以亭、廊,杂以花木,乃为淮北首屈一指之山水园,亦是淮盐文化的重要体现。其在建筑形式、植物配置等方面有借鉴欧式之手法,并与中国传统园林相结合。本文主要通过文献考证、现场调研和访谈的方法,对该园的基本布局进行了复原,对其历史沿革及造园特色进行了探讨。 相似文献
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关于荒溪分类 总被引：6，自引：1，他引：6
王礼先 《北京林业大学学报》1982,(3)
阐明了荒溪、泥石流及泥石流荒溪的定义。归纳并分析了某些欧洲国家,苏联、日本及中国百余年来荒溪的分类方法及分类因子。提出了根据主导因子,采用定性与定量相结合的荒溪分类新方法。在分析现有的确定山洪及泥石流运动参数的方法的基础上,作者按照荒溪类型提出了有关参数的应用范围。 相似文献
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选取抚顺地区2018年10月9日、28日2次冷涡天气过程,利用常规气象资料对高空环流背景、地面形势以及水汽条件特征进行了对比分析。2次天气过程预报员均出现漏报现象。通过对2次过程的天气形势分析以及数值预报检验,发现欧洲中心细网格(数值预报)对于高空冷涡配合地面倒槽产生的降水预报时间比实际降水时间延迟;对冷涡后部配合地面低压产生的降水预报时间比实际降水提前。预报员主观预报出现漏报的原因主要缘于对冷涡天气系统的发生、发展机理及结构认识不足,对水汽、抬升等关键降水要素缺乏合理的预报订正经验。 相似文献
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Vitousek PM Ladefoged TN Kirch PV Hartshorn AS Graves MW Hotchkiss SC Tuljapurkar S Chadwick OA 《Science (New York, N.Y.)》2004,304(5677):1665-1669
Before European contact, Hawai'i supported large human populations in complex societies that were based on multiple pathways of intensive agriculture. We show that soils within a long-abandoned 60-square-kilometer dryland agricultural complex are substantially richer in bases and phosphorus than are those just outside it, and that this enrichment predated the establishment of intensive agriculture. Climate and soil fertility combined to constrain large dryland agricultural systems and the societies they supported to well-defined portions of just the younger islands within the Hawaiian archipelago; societies on the older islands were based on irrigated wetland agriculture. Similar processes may have influenced the dynamics of agricultural intensification across the tropics. 相似文献
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商品化转基因植物的外源基因及其检测技术 总被引：1，自引：0，他引：1
随着多种生物基因组的测序、分子生物学及转基因技术的发展,被批准大田释放的转基因植物越来越多。本文总结了转基因植物涉及的外源基因 相似文献
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我国是世界上人工林面积最大的国家,人工林对我国的生态环境建设和经济发展
发挥着重
大作用。但由于长期沿用传统粗放的管理方式,使得我国人工林质量低下,生态功能较
差。通过深
入分析了我国人工林经营中存在的诸如病虫害严重、地力衰退、生物多样性下降等问题
,借鉴欧洲
近自然森林经营理论和技术,并结合我国实际,提出了重视生境评价和演替规律研究,
对现有人工
林,按照不同类型,采取科学有效的方法如团状采伐、带状采伐、单株采伐等创造林窗
,进而通过人
工造林或天然更新的方式促其形成复层异龄混交林而实现近自然化改造;以合理的收获作
业恢复
地力、通过法律和政策体系规范人类经营活动等我国人工林近自然经营的有效途径。 相似文献
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Jan Pieter VAN DER BERG Gijs A. KLETER Evy BATTAGLIA Martien A. M. GROENEN Esther J. KOK 《农业科学与工程前沿(英文版)》2020,7(2):136-147
Genetic modification techniques, in particular novel gene editing technologies, hold the yet unfulfilled promise of altering genetic traits in farm animals more efficiently than by crossbreeding, allowing for a more rapid development of new cattle breeds with distinct traits. Gene editing technologies allow for the directed alteration of specific traits and thereby have the potential to enhance, for instance, disease resilience, production yield and the production of desired substances in milk. The potential implications of these technological advancements, which are often combined with animal cloning methods, are discussed both for animal health and for consumer safety, also with consideration of available methods for the detection and identification of the related products in the food supply chain. Finally, an overview is provided of current regulatory approaches in the European Union (EU) and major countries exporting beef to the EU, for products from animals bred through established practices as well as modern biotechnologies. 相似文献
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Tennessen JA Bigham AW O'Connor TD Fu W Kenny EE Gravel S McGee S Do R Liu X Jun G Kang HM Jordan D Leal SM Gabriel S Rieder MJ Abecasis G Altshuler D Nickerson DA Boerwinkle E Sunyaev S Bustamante CD Bamshad MJ Akey JM;Broad GO;Seattle GO;NHLBI Exome Sequencing Project 《Science (New York, N.Y.)》2012,337(6090):64-69
As a first step toward understanding how rare variants contribute to risk for complex diseases, we sequenced 15,585 human protein-coding genes to an average median depth of 111× in 2440 individuals of European (n = 1351) and African (n = 1088) ancestry. We identified over 500,000 single-nucleotide variants (SNVs), the majority of which were rare (86% with a minor allele frequency less than 0.5%), previously unknown (82%), and population-specific (82%). On average, 2.3% of the 13,595 SNVs each person carried were predicted to affect protein function of ~313 genes per genome, and ~95.7% of SNVs predicted to be functionally important were rare. This excess of rare functional variants is due to the combined effects of explosive, recent accelerated population growth and weak purifying selection. Furthermore, we show that large sample sizes will be required to associate rare variants with complex traits. 相似文献
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Spahni R Chappellaz J Stocker TF Loulergue L Hausammann G Kawamura K Flückiger J Schwander J Raynaud D Masson-Delmotte V Jouzel J 《Science (New York, N.Y.)》2005,310(5752):1317-1321
The European Project for Ice Coring in Antarctica Dome C ice core enables us to extend existing records of atmospheric methane (CH4) and nitrous oxide (N2O) back to 650,000 years before the present. A combined record of CH4 measured along the Dome C and the Vostok ice cores demonstrates, within the resolution of our measurements, that preindustrial concentrations over Antarctica have not exceeded 773 +/- 15 ppbv (parts per billion by volume) during the past 650,000 years. Before 420,000 years ago, when interglacials were cooler, maximum CH4 concentrations were only about 600 ppbv, similar to lower Holocene values. In contrast, the N2O record shows maximum concentrations of 278 +/- 7 ppbv, slightly higher than early Holocene values. 相似文献
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引进马铃薯品种在云南的适应性评价 总被引：8，自引：1，他引：7
以云南广泛种植的马铃薯品种会-2、合作88为对照,2007年冬季在云南省昆明市晋宁县富有乡对来自欧洲法国的19份栽培马铃薯品种的适应性进行了评价,以期明确欧洲马铃薯品种在云南马铃薯遗传改良和生产应用中的可能性.以3次重复完全随机区组设计试验,在田间和室内进行了产量性状、农艺性状、蒸煮品质、外观品质(薯形、薯皮类型、皮色、肉色、芽眼)、淀粉含量、炸片品质等6类性状的评价.结果表明,大部分性状在品种间差异显著或极显著,评价性状的多样性信息(PIC)丰富,其和云南生产品种的相似度差异明显.大部分欧洲马铃薯在云南昆明的小春作条件下难于直接利用,可以利用欧洲马铃薯品种的优良性状来拓宽云南马铃薯的遗传基础,特别是在产量性状、农艺性状、外观品质、蒸煮品质及淀粉含量方面,其中H-43表现出产量和对照持平,且外观品质优于对照,可以进行生产试验以便在生产上推广应用. 相似文献
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为探讨长时间低剂量福尔马林对鱼类及循环水养殖系统的影响,以欧鲈(Dicentrarchus labrax)为受试鱼在循环水养殖系统中进行实验。设置4个福尔马林浓度处理组(0 mg/L、30 mg/L、60 mg/L和90mg/L)进行分析,结果表明,30 mg/L福尔马林处理后,欧鲈存活率(98%)和增重率（350.26%）与对照组之间无显著性差异（P>0.05）;90 mg/L福尔马林处理使生物滤器去除亚硝酸盐氮效能产生明显削弱作用;30 mg/L福尔马林处理的欧鲈肠道内AMS和胃中的胰蛋白酶活性显著增加（P<0.05）。60 mg/L福尔马林处理使欧鲈肝脏遭到一定程度的损伤,且60 mg/L和90 mg/L福尔马林处理的欧鲈出现了轻度逆境胁迫。90 mg/L福尔马林处理的水体中亚硝酸盐氮的浓度升高,亚硝酸盐氮的去除率显著降低（P<0.05）,对去除氨氮的影响滞后于对去除亚硝酸盐氮的影响。 相似文献