生态安全及其研究进展

生态安全是国家安全的重要组成部分,其研究目前主要集中在对生态安全的认识、评估上,而保障生态安全的技术与方法、生态安全维护等方面则有待进一步深入研究。论述了生态安全的定义、生态安全研究的内容,总结概括了国内外生态安全的研究现状及其研究特点。     

区域农业可持续发展的生态安全评价——以宁夏红寺堡移民区为例

以宁夏红寺堡移民区为例,构建了其农业可持续发展的生态安全评价指标体系,采用均方差确定了评价指标的权重,对研究区1999、2000、2001、2002、2003、2004、2005、2006年8年的农业生态安全进行了评价,从评价结果可以看出,红寺堡移民区农业生态安全总体呈下降态势,安全等级处于Ⅲ一Ⅳ级,安全状态从敏感态下降到风险态．2004年是研究区农业生态安全变化的转折点,从2004年起,农业生态安全有所回升．在分析变化原因的基础上,提出农业可持续发展的生态安全建设对策．     

农业生态安全的概念和研究方法初探

文章阐述了农业生态安全理论的形成和发展,分析了农业生态安全评价的基本原则和评价内容,并在此基础上探讨了统计学模型、生态承载力方法和生态模型法等生态安全的评价方法。     

“第十四届中国农业生态学学术研讨会”征文

“第十四届中国农业生态学学术研讨会”初定于2009年8月中旬在福州市召开。会议由中国生态学会主办,福建农林大学承办。大会主题为“农业生态健康与农业生态安全”,下设9个专题：高效生态农业模式与技术及健康食品生产;农业生物多样性保护与生物入侵;农业生态系统服务功能与过程;农业生态系统健康与区域农业生态安全;农业循环经济与节能减排;农业土地合理流转与粮食安全;     

广西农业生态经济系统安全评价与预警研究

开展长时间序列的广西农业生态经济系统安全评价、安全影响因素和安全预警研究,可为系统安全调控、农业可持续发展和乡村振兴提供决策参考。本研究采用生态足迹模型核算2000-2021年广西农业生态经济系统人均生态足迹和人均生态承载力,通过资源利用效率指数、生态盈亏、生态压力指数评价系统安全状况,利用偏最小二乘(PLS)模型分析系统安全的影响因素,基于灰色GM(1,1)模型开展系统安全预警,并将预警结果与云南、贵州进行比较。结果表明,2000-2021年广西农业生态经济系统人均生态足迹增长90.30%,其中林地增长最快,耕地占比最大;人均生态承载力下降0.67%;系统资源利用效率提高72.97%,但2011年以来增幅较小;系统生态赤字从-0.395 hm²/人不断加剧到-1.292 hm²/人,生态压力指数从1.66升高到3.18,系统从中度不安全状态逐渐转变为重度不安全状态,并开始进入极度不安全状态;人均耕地面积和耕垦指数对系统安全具有正向影响;2022-2033年系统安全由重警转为巨警,警情等级高于贵州和云南。因此,要提高耕地保护力度,促进农业转型...     

种植业生态安全评价——以重庆市沙坪坝区为例

基于农业生态安全,从资源、环境、社会经济等3个方面构建种植业生态安全评价体系;用极差标准化法处理原始数据,用层次分析法(AHP)确定指标权重,选用加权函数法和"障碍度"模型对重庆市沙坪坝区1995—2010年种植业生态安全进行研究。结果显示:1)种植业生态安全综合指数由1995年的0.272 2上升到2010年的0.647 7;2)资源对种植业生态安全障碍度由1995年的28.83%上升到2010年的34.39%,环境和社会经济对种植业生态安全障碍度分别由1995年的46.37%、24.80%下降到2010年的21.78%、9.68%;3)农村人均耕地面积、化肥施用强度、农药施用强度、地膜施用强度和酸雨频率是沙坪坝区种植业生态安全的主要障碍因子。自1995年来沙坪坝区种植业生态安全水平逐年提高,今后通过加强资源保护、提高环境治理力度、加大农业基础建设投资可以提高种植业生态安全水平。     

种植业生态安全评价——以重庆市沙坪坝区为例

基于农业生态安全,从资源、环境、社会经济等3个方面构建种植业生态安全评价体系;用极差标准化法处理原始数据,用层次分析法(AHP)确定指标权重,选用加权函数法和“障碍度”模型对重庆市沙坪坝区1995-2010年种植业生态安全进行研究.结果显示:1)种植业生态安全综合指数由1995年的0.272 2上升到2010年的0.647 7;2)资源对种植业生态安全障碍度由1995年的28.83％上升到2010年的34.39％,环境和社会经济对种植业生态安全障碍度分别由1995年的46.37％、24.80％下降到2010年的21.78％、9.68％;3)农村人均耕地面积、化肥施用强度、农药施用强度、地膜施用强度和酸雨频率是沙坪坝区种植业生态安全的主要障碍因子.自1995年来沙坪坝区种植业生态安全水平逐年提高,今后通过加强资源保护、提高环境治理力度、加大农业基础建设投资可以提高种植业生态安全水平.     

生态安全与生态安全研究

生态安全研究是近年发展起来的研究领域 ,本文分析总结了生态安全的概念 ,提出了生态安全研究内容基本框架 ,并对国内外生态安全研究趋势进行了初步介绍。认为生态安全是指一个国家或地区生态环境的状况能持续满足社会经济发展需要 ,社会经济发展不受或少受来自于生态环境的制约与威胁的状态。生态安全包括资源安全和环境安全两方面含义。生态安全研究内容应该包括生态 (资源环境 ,下同 )安全评估、生态安全监测、生态安全趋势预测、生态安全政策、生态安全恢复方法对策等主要方面。生态安全研究开展的时间较短 ,目前 ,主要集中在生态安全认识、生态环境治理与恢复方面 ,生态安全评估研究已经起步 ,生态安全监测、预测等研究则有待进一步深入。     

城市湿地与城市生态安全关系初探

在分析城市生态安全范畴的基础上,阐明了城市湿地在城市生态安全中的作用和地位,提出了城市湿地目前存在的主要问题和对策.分析成果将增强人们对城市湿地与城市生态安全之间关系的认识,为开展城市湿地的科学保护、建设、开发活动,维护城市生态安全和促进城市可持续发展提供依据.     

茶叶安全用药的实践与对策探讨

茶叶安全用药是以保护茶树安全生产的前提下,以减少使用化学农药为目标,保护自然天敌资源,利用微生物制剂、抗生素制剂、生物物理诱控、植物源农药、生态调控等,环境友好型防控技术措施来控制有害生物的行为。近年来,在全国农业技术推广中心指导下,开展"茶叶安全用药的实践与对策"研究,在工作中积累了比较丰富的经验,对绿色防控的发展趋势形成了比较清晰的认识。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…