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Search Results: 1 - 10 of 301414 matches for " regulation<br>啄洞 "
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Influence of potential cavity resources on secondary cavity-nesters and breeding bird community composition
潜在洞巢资源差异对次级洞巢鸟及繁殖鸟类群落的影响

Daqing Zhou,Chunfa Zhou,Wenhong Deng,
周大庆
,周春发,邓文洪

生物多样性 , 2009,
Abstract: To explore how density of potential cavity resources (including cavities and artificial nest boxes) affects the composition and distribution of secondary cavity-nesting guilds, as well as the community structure of breeding birds, we studied plots with different densities of nest cavities in Dagang Forestry Farm, Jilin Province, China from November 2007 to July 2008. Based on the density of cavity resources, the nine sample sites were divided into three treatments, i.e., NBP (nest-box plots with less cavities and high-density nest boxes), LDP (low-density cavities plots without nest boxes) and HDP (high-density cavities plots without nest boxes). We then surveyed avian communities and noted the use of cavities and artificial nest boxes. All the treatments contained four primary cavity excavators, and three species were the same. Four secondary cavity nesters were widespread in the three treatments, including the great tit {Parus major), marsh tit (P. palustris), yellow-rumped flycatcher (Ficedula zanthopygia) and eurasian nuthatch (Sitta europaea). Total densities of secondary cavity nesters in NBP and HDP were higher than that of LDP. Densities of great tits and yellow-rumped flycatchers were higher in NBP and HDP than in LDP, because they were major users of nest boxes. There were no significant differences in the densities of marsh tits and eurasian nuthatches among treatments. A significant positive correlation was detected between the density of primary cavity excavators and cavity density, and also between the density of secondary cavity nesters and potential cavity resources. Bird species diversity indices were lower in LDP than in NBP and HDP. Nest-box addition could potentially regulate the composition of avian communities by increasing bird species diversity indices. We observed no differences in evenness, species richness indices or probability of interspecific encounter (PIE) among treatments, and Serensen similarity indices differed little among treatments. There were no obvious differences in structure of breeding bird guilds between HDP and LDP. Nine species were found in all the three treatments, and their densities were not affected by the temporary increase in secondary cavity nesters. We hypothesize that density of primary cavity excavators determines the density of cavities in forests, which may change distributional patterns of secondary cavity-nester guilds, and therefore affect the structure of breeding avian communities.
潜在洞巢资源差异对次级洞巢鸟及繁殖鸟类群落的影响
周大庆,周春发,邓文洪*
生物多样性 , 2009,
Abstract: ?为了解次生林中潜在洞巢资源(包括各种啄木鸟的啄洞和人工巢箱)的多寡对次级洞巢鸟集团及繁殖鸟类群落结构的影响,2007年11月至2008年7月,我们在吉林省吉林市大岗林场选择洞巢密度不同的样地,对其次级洞巢鸟及鸟类群落结构进行了比较研究。根据洞巢资源密度我们将9块样地分为3组,即巢箱区(啄洞密度最低,悬挂人工巢箱使其潜在洞巢资源总密度大幅提高)、低密度区(啄洞密度较低,无巢箱)和高密度区(啄洞密度较高,无巢箱),调查了3组样地内鸟类的组成和密度、潜在洞巢资源的利用情况等。3组样地中均调查到4种初级洞巢鸟,其种类组成略有不同;4种次级洞巢鸟在3组样地广泛分布,分别为白眉姬鹟(ficedulazanthopygia)、大山雀(parusmajor)、沼泽山雀(p.palustris)和普通鳾(sittaeuropaea)。巢箱区和高密度区的次级洞巢鸟总密度显著高于低密度区。巢箱区同高密度区一样,大山雀和白眉姬鹟的密度显著高于低密度区,这是由于大山雀和白眉姬鹟是人工巢箱的主要利用鸟种,而沼泽山雀和普通鳾的密度在三组样地间差异不显著。初级洞巢鸟总密度与啄洞密度、次级洞巢鸟总密度与潜在洞巢资源总密度都呈显著正相关关系。潜在洞巢资源丰富的样地中鸟类群落多样性指数显著高于潜在洞巢资源贫乏样地中的鸟类群落多样性指数,人为增加洞巢资源可以改变鸟类群落组成并显著提高群落的多样性指数。三组样地中鸟类群落的均匀性、丰富度指数和种间相遇率没有显著差异,群落相似性指数也相近。高密度区和低密度区鸟类群落集团结构相似。次级洞巢鸟密度的增加短时期内未对群落内其他主要鸟种的密度产生显著影响。研究结果显示,初级洞巢鸟的密度决定了啄洞的丰富程度,而洞巢资源的差异会对次级洞巢鸟集团的分布模式产生影响,进而影响整个繁殖鸟类群落的结构。
贵州水银洞金矿矿层矿化分析与深部预测
刘帅,彭进,刘建中,王泽鹏,杨成富
- , 2016,
Abstract: 水银洞金矿为滇黔桂“金三角”最重要的金矿床,是典型的卡林型层控金矿床。运用绘制等高线图和含矿层矿化分 布图的方法,对水银洞矿床0~427勘探线的钻孔数据分析,并用surfer 软件绘制矿层的顶底板和地层矿化趋势的模拟图,重 点分析了含矿地层的构造形态和矿化规律,结果显示:界面等高线反应背斜的形态,水银洞矿区背斜的高点和背斜倾伏端 是金矿的主要赋存位置;Sbt(构造蚀变体) 与上部龙潭组矿化值有负相关效应;水银洞矿化整体具有不均匀性,Sbt向东 南延伸且在东西向具有弱—强—弱的富集规律。Sbt矿化强度在东西向具有弱—强—弱的规律,而龙潭组地层中的矿化与 Sbt呈现一定负相关效应,在背斜倾伏端龙潭组矿化度开始增强,预示深部地层可能还会有大规模的工业矿体存在。
The Shuiyindong gold deposit is one of the most important gold deposits in Yunnan-Guizhou-Guangxi“golden triangle”area, southwestern China and it is a typical Carlin-type strata-bound gold deposits. In this study, we analyzed the borehole data of No.0~427 prospecting line by drawing a contour map and a distribution map of mineralization trending degree in ore-bearing strata. The study uses the Surfer software to draw the simulation diagram of deposits boundary and the mineralization trend. The study is focused on analyzing the structure geometry and mineralization pattern of ore-bearing strata in the Shuiyindong mining area. Our analysis reveals that interface contour line reflects the shape of the anticline. Also, the main locations of gold deposits are at the hinge area of the anticline and the plunging end of the anticline in the Shuiyindong gold deposit. There existed a negative correlation between Sbt (structurally altered rock body) and the upper part of the Longtan Formation in the mineralization degree; and the mineralization of the Shuiyindong gold deposit shows obvious inhomogeneity; In addition, the mineralization degree of Sbt has a regular distribution of a weak-strong-weak pattern along the east-west directionn and the mineralization degree in the Longtan Formation shows a negative correlation with the SARB. The mineralization degree is enhanced at the plunging end of the anticline in the Longtan Formation, suggesting that a large-scale industrial ore body may exist in the deep part of the strata.
留存收益的资本成本分析——对“啄序理论”的再解释
王志亮,李宗祥,齐晓国
财会月刊 , 2006,
Abstract: 中外财务教科书都把留存收益视为与普通股相同的资本,将其资本成本确定为等同或略低(考虑到其没有筹资费用)于普通股的资本成本,并参加公司综合资本成本的计算。然而,当以市价作为计量基础计算普通股的价值时,股价本身已经包含了留存收益因素,再让它单独作为一种股权资本参加资本成本的加权平均计算,属股权资本成本的重复计算,会高估公司综合资本成本。此结论从资本成本的角度对西方筹资的“啄序理论”与资本成本理论相悖的现象做出了合理的阐释。  【关键词】留存收益资本成本啄序理论一、西方筹资的“啄序理论”存在的缺陷  根据西方成熟的财务理论,公司所有资本大体可分为两类,即股权资本和债权资本,他们给企业带来的资本成本存在重大差异。在市场平均报酬率既定的情况下,企业的资本成本取决于投资者对投资风险的补偿(风险报酬)要求,由于股权投资的风险大于债权投资的风险,投资者对股权投资要求的报酬必然要高于债权投资;又因为债务利息可在税前列支从而能使企业获得减税利益,再加上股权筹资的筹资费用相对较高,这就使得企业股权资本的成本大大高于债权资本的成本。因此,基于对资本成本的考虑,在其他因素一定的情况下,企业筹资应优先考虑债权筹资。
我国股票市场监管效率研究
Study on Regulation Efficiency of China’s Stock Market
 [PDF]

潘雨晨, 邵向阳
Advances in Social Sciences (ASS) , 2016, DOI: 10.12677/ASS.2016.51027
Abstract:
我国股票市场的监管效率还较为低下,主要表现为:监管法律法规不完善、监管体系不健全、违规处罚力度过轻、行政干预过度等。本文从股票市场监管的中间目标和根本目标入手,选取股票发行的监管效率、监管者的执法效率、股票市场监管的社会效率作为指标,运用描述性统计分析法和事件研究法对我国股票市场监管效率进行研究,同时还分析了导致监管效率低下的原因,并提出了相应的改进建议。
The regulatory efficiency of Chinese stock market is still relatively low. The law is not perfect, the regulatory system is not complete, the degree of punishes cases is too weak, and the administrative interference is too heavy. Starting with the intermediate target and the basic target of the stock market supervision, this paper selects the regulation efficiency of issuing shares, the law enforcement efficiency of regulators, the economic efficiency of stock market as studying indexes. Descriptive statistical analysis and event study method are used in this research to study on the regulatory efficiency of Chinese stock market. At the meantime, this paper also analyzes the reasons for low efficiency of supervision and puts forward relevant suggestions for improvement.
混合传感网络覆盖洞修复改进算法研究
Improved Recovery Algorithms of Coverage Holes in Hybrid WSN

于秦,王伟东,李龙江,钱艇
- , 2017, DOI: 10.3969/j.issn.1001-0548.2017.04.010
Abstract: 针对传统的无线传感网络覆盖洞修复算法VOR(VORonoi algorithm)存在的不足,该文在混合传感网络环境下提出基于优先机制的VORP(Priority-based VOR)和基于复杂优先机制的VORCP两种改进的覆盖洞修复算法。通过对两种改进算法进行仿真和分析,以及对运用修复算法前和分别运用VOR、VORP、VORCP算法后,监测区域无线传感网络覆盖情况的纵向与横向的比较分析,结果表明该文所提出的改进算法在性能和效率上均优于传统的覆盖洞修复算法。
交叠隧道相互影响性研究
Research on the Interaction of Upper and Lower Tunnels

李明,王元韩,刘凡,王勇
- , 2017,
Abstract: 摘要 随着隧道邻近建筑物施工的增多,如何确保邻近建筑物与隧道结构物交叉段的安全成为施工中的难题。采用三维有限元方法,对具有横洞隧道下穿既有隧道进行模拟和分析。研究表明,当新建隧道下穿既有隧道时,二者相互“吸引”,既有隧道沉降沿自身轴线呈“拱形”曲线分布,且受力增大,远离交叉段影响逐渐减小;横洞开挖对主洞的影响表现为交接处拱顶、拱腰受力增加,下沉量增加,周边收敛减少,出现应力集中现象。研究成果对具有横洞的交叉隧道的安全施工有一定的指导意义。
Norma y principio en el "Jus commune"
Carpintero,Francisco;
Revista de estudios histórico-jurídicos , 2005, DOI: 10.4067/S0716-54552005000100013
Abstract: this article presents a synthesis of some aspects in the method used by the jus commune jurists and by some theologians influenced by it. the author makes a clear distinction between two instances of the reflection over the juridical science. one, that previous to the xvii century; the other, that at the onset of the xvi century which, on the general philosophical level, was the one represented by gabriel vásquez de belmonte, luis de molina, and francisco suárez. gabriel vásquez fiercely rebelled against thomas of aquinas -and, with him, against the spirit of practical medieval philosophy- and molina and suárez followed suit. the work of these theologians is characterized by their adoption of the ex objecto in ethics, according to which good and evil intrinsically and radically depend on behavior itself, so that practical knowledge is determined by knowledge of the nature of things in the divine mind; therefore, manente natura rationali, good shall always be good, and the same shall be true of morally evil acts. the most immediate consequence is that the natural law doctrine was filled with eternal and immutable essences. the middle ages had not seen the relationships between the general (rather, theoretical) instance and the practical, always concrete, instance in this way. the article is supported by the works of pedro de bellapertica, albertus bolognettus, fran?ois conan, johannes althusius and, among the theologians, thomas of aquinas in particular, to show what johann eisenhart would explain in mid-enlightenment: that logic is always rigid and goes from the general to the particular, whereas metaphysics teaches us to learn that the causes come from the effects, the principles from the principiata, the first elements from the last ones, the antecedent from the consequence, and the whole from its parts.
南海大鹏湾夜光藻种群在其生态群落中的地位和功能
黄长江,杞桑,齐雨藻,林小涛,欧强
海洋与湖沼 , 1997,
Abstract: 分析了1991年上半年南海大鹏湾盐田水域夜光藻(Noctiluca scintillans)和浮游动、植物之间的种群动态关系。结果表明,在春季高峰期3月至5月初,调查海域共出现12个夜光藻和浮游动、植物高峰。其中,以发生4次赤潮的夜光藻种群占主导地位,其次是棱角类的鸟啄尖头蚤(Penilia avirostris),其最高数量高达96238 ind./m3。相比之下,在夜光藻和枝角类鸟啄尖头蚤捕食压力的影响下,浮游植物(尤其是硅藻)的春季高峰并不显著。调查结果表明夜光藻的过度繁殖(>1103 cell/L),不但对产浮游性卵的桡足类、甲壳类及鱼卵仔鱼具明显的捕食压力,而且使浮游动物种类多样性降低。调查水域在3-5月,以不到6d的周期出现1个生产高峰。这种高生产力即体现了富营养化程度较高的近岸水域的特性,又是生态系整体构造的衰退、生物多样性降低和食物链的缩短的表现。
重庆丰都三峡地区宋代油桐材料的发现与意义
王运辅,武仙竹,邹后曦,黄秒斌
重庆师范大学学报(自然科学版) , 2014, DOI: 10.11721/cqnuj20140510
Abstract: 油桐(Verniciafordii)是起源于中国的油料树种;利用油桐种子提炼的桐油是非常重要的工业原料,在中国古代工业及世界近现代工业生产中产生过巨大影响。油桐开发、利用从唐代以来已有较多文献资料介绍,中国现代经济史研究中也一直把油桐种植史作为热点之一,但在考古发现中却一直未获得过古代油桐树实物标本。2013年,重庆市文化遗产研究院、重庆师范大学研究人员在重庆市丰都县瓦啄嘴遗址考古发掘工作中,从一座宋代瓷窑火膛里发现了宋代油桐树实物材料,这是在中国国内首次发现古代油桐树实物标本。所发现的材料包括10枚油桐树种子和一些树干(木炭)标本。从种子形态观察,所发现油桐应属于三年桐的栽培品种。木炭标本的切片观察结果,也证明该标本属于油桐树木材。该发现表明文献中记录三峡地区广泛种植的油桐应属于三年桐系列,三峡地区很可能是我国三年桐品种经济林发源地。木材消耗量巨大的瓷窑烧造生产中,把油桐树作为燃料利用,反映宋代三峡地区古居民对油桐树的开发利用,已形成了油料资源(种子)、柴薪资源(树干)的经济林综合利用模式。该经济林经营模式对今天的三峡库区生态文明建设具有重要参考价值。
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