共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
3.
4.
中国蜘蛛物种多样性分析 总被引:1,自引:0,他引:1
基于2011年1月更新的世界蜘蛛名录第11.5版,本文对中国蜘蛛的物种多样性进行了统计和分析:(1)目前中国共记述蜘蛛67科670属3667种,种数占世界蜘蛛的8.72%,仍有许多物种尚待发现;(2)目前中国特有蜘蛛物种共计2376种,占中国蜘蛛种数的64.79%、世界蜘蛛种数(42055种)的5.65%,表明中国蜘蛛特有物种极为丰富,为中国生物多样性的保护、环境及气候的历史演变和蜘蛛的系统演化研究起到重要作用;(3)已知蜘蛛物种数最多的省份为云南(728种,占19.85%)、湖南(612种,占16.69%)、四川(454种,占12.38%)等,一定程度上表明上述各省生物多样性丰富,但这一结果也与各地蜘蛛多样性研究不均衡有关。蜘蛛各科名录及统计数据可参见“中国蜘蛛特有物种网”。 相似文献
5.
6.
拟壁钱属Oecobius和壁钱属Uroctea蜘蛛之间系统发生关系存在一定的争议.为从分子水平探讨两属间系统发生关系,本研究测定了5科6种蜘蛛的16S rRNA基因部分序列,并联合来自GenBank的8科8种蜘蛛16S rRNA基因序列数据重建分子系统树.结果表明,拟壁钱属和壁钱属间遗传距离(28.1%)明显大于复杂生殖器类(Entelegynae)蜘蛛属间遗传距离的平均值(22.9%);与目前大多数文献把拟壁钱属和壁钱属并在一个科的观点相反,本研究重建的系统发生树显示两属不是姊妹群.作者建议把拟壁钱属和壁钱属分别重新划回拟壁钱科Oecobiidae和壁钱科Urocteidae.系统发生树还验证了简单生殖器类(Haplogynae)蜘蛛、复杂生殖器类蜘蛛各自的单系性以及筛器类(Cribellate)蜘蛛的多系发生,同时本文的结果还对圆网蛛类(Orbiclariae)单系发生及RTA类群单系发生的有效性提出了质疑. 相似文献
7.
8.
9.
10.
2种不同采样方法对麦田蜘蛛群落结构的比较研究 总被引:1,自引:0,他引:1
分别于1998年11月到1999年5月和1999年11月到2000年5月间,在位于武汉市武昌区的沙湖边,使用样方和陷阱法系统采样,研究了裸粒大麦田的蜘蛛群落结构。研究结果显示,1998-1999年麦田蜘蛛群落由11科44种蜘蛛组成,1999-2000年麦田蜘蛛群落由14科59种蜘蛛组成;相同年份不同采样方法获得的蜘蛛群落优势种组成不同,陷阱法采样获得的优势种集中在皿蛛科、狼蛛科和平腹蛛科,而样方采样虽然也以皿蛛科和狼蛛科蜘蛛为主,但球蛛科、肖蛸科和园蛛科蜘蛛的比例明显上升;不同的年份使用相同的采样方法获得的蜘蛛优势种组成不同,显示了群落结构的年际变动。对2种采样方法获得的群落相似性分析显示,不同采样方法获得的群落结构相似性较小。 相似文献
11.
12.
Jonathan I. Charney 《Ocean Development & International Law》2013,44(3-4):233-288
Abstract This paper will set the international background for the evolution of the Exclusive Economic Zone (EEZ) concept in international law and in state practice. It will review the relevant provisions of the UNCLOS III and will discuss the extent to which they have or are likely to guide national practice in the future. The paper will also examine the Reagan Proclamation from an international legal perspective, as well as the possible impact of action taken by the United States in fashioning its EEZ on the stability of the EEZ concept internationally. 相似文献
13.
Ontology-based knowledge representation for bioinformatics 总被引:8,自引:0,他引:8
14.
Abstract This paper will analyze and evaluate the issues that might emerge between the United States and both Canada and Mexico in the establishment of adjacent exclusive economic zones (EEZs). Given the ambiguity of the U.N. Convention language and historic differences in approach to law of the sea issues, it is likely that there will be differences in how each of these countries will manage and regulate activities within their respective zones. Since many of the resources and activities are transboundary in nature, the potential for conflict between states exists. The paper will serve to highlight existing areas of conflict and will evaluate the potential for future disagreements. 相似文献
15.
为船舶、乐器等特殊行业需要的弦切板数控加工提供数学描述理论,提出的这些理论将为数控加工的数学模型建立提供基础理论,为板材纹理的视频再现提供数学方法.本文提出的理论还将为三角形下锯法提供理论依据,与制材工艺结合起来,将使传统加工工艺数学化,为科学管理和数字化控制提供了理论.本文是木材工业中用数学描述加工过程的开始,可以推进木材工业加工过程数学描述研究的开展. 相似文献
16.
This paper will review the basics of neurostimulation in the perioperative period. Following a brief overview of neuromuscular physiology, the mechanism of action of depolarizing and non-depolarizing relaxants will be discussed. The principles of neurostimulation will then be applied clinically when different patterns of stimulation (single twitch, train-of-four, post-tetanic twitch count, double burst) are described. Clinical assessment of neuromuscular function will then be compared with both subjective and objective means of assessment of adequacy of intraoperative relaxation and postoperative reversal. The principles reviewed in this paper will then be applied in the clinical setting, and risks and benefits associated with perioperative use of muscle relaxants will be discussed. 相似文献
17.
原木形状分段描述方法的数学描述理论研究 总被引:4,自引:0,他引:4
为制材、木材检尺等特殊行业需要的原木数控检测提供数学描述理论,提出的这些理论将为数控检测的数学模型建立提供具体的数学方法,为原木形状的视频再现提供编程的数学工具.本文提出的理论还将为数控下锯法提供理论依据,与制材工艺结合起来,将使传统原木检测数字化,为科学管理原木和数字化统计与检尺控制提供了理论,本文是木材工业中用数学描述检测过程的开始.通过本文的研究,可以推进木材工业检测过程数学描述研究的开展. 相似文献
18.
Johann J. Go 《Journal of bioethical inquiry》2018,15(4):527-534
Transgender people have among the highest rates of suicide attempts of any group in society, driven strongly by the perception that they do not belong in the sex of their physical body. Gender reassignment surgery (GRS) is a procedure that can change the transgender person’s physical body to accord with their gender identity. The procedure raises important ethical and distributive justice concerns, given the controversy of whether it is a cosmetic or medical procedure and the economic costs associated with performing the procedure. This paper argues that there is a strong case for funding GRS as a matter of clinical necessity and justice. This paper will be divided in four key sections: First, the state of transgender health will be outlined, including the role of GRS and common objections to it. Second, a number of common objections to GRS will be analysed at the outset and shown to be unconvincing. Third, a constructive argument will be advanced, arguing that publicly funded GRS is clinically necessary, cost-effective, and demanded by principles of justice. Fourth, the paper will briefly discuss moralistic biases and why we demand a higher burden of justification for funding GRS compared with other analogous procedures. 相似文献
19.
This paper presents one possible implementation of a transformation that performs linear mapping to a lower-dimensional subspace. Principal component subspace will be the one that will be analyzed. Idea implemented in this paper represents generalization of the recently proposed infinity OH neural method for principal component extraction. The calculations in the newly proposed method are performed locally--a feature which is usually considered as desirable from the biological point of view. Comparing to some other wellknown methods, proposed synaptic efficacy learning rule requires less information about the value of the other efficacies to make single efficacy modification. Synaptic efficacies are modified by implementation of Modulated Hebb-type (MH) learning rule. Slightly modified MH algorithm named Modulated Hebb Oja (MHO) algorithm, will be also introduced. Structural similarity of the proposed network with part of the retinal circuit will be presented, too. 相似文献
20.
A bioinformatics approach to investigating developmental pathways in the kidney and other tissues. 总被引:3,自引:0,他引:3
J B Bard 《The International journal of developmental biology》1999,43(5):397-403
Over the past few years, large amounts of data linking gene-expression (GE) patterns and other genetic data with the development of the mouse kidney have been published, and the next task will be to integrate these data with the molecular networks responsible for the emergence of the kidney phenotype. This paper discusses how a start to this task can be made by using the kidney database and its associated search tools, and shows how the data generated by such an approach can be used as a guide to future experimentation. Many of the events taking place as the kidney develops do, of course, also take place in other tissues and organisms and it will soon be possible to incorporate relevant information from these systems into analyses of kidney data as well as the new information from microarray technology. The key to success here will be the ability to access over the internet data from the textual and graphical databases for the mouse and other organisms now being established. In order to do this, informatic tools will be needed that will allow a user working with one database to query another. This paper also considers both the types of tools that will be necessary and the databases on which they will operate. 相似文献