共查询到20条相似文献，搜索用时 171 毫秒
1.
《中国科学院院刊(英文版)》2008,22(2):75-75
Horseflies are a blood-feeding arthropod notorious as a common pest of animals and sometimes of humans. While a target of the biological control in green farming and animal husbandry, dried bodies of the females, known as mangchong, are used in traditional Chinese medicine （TCM） to treat cardiovascular diseases. 相似文献
2.
Among the galaxy of research development organizations in northwest Beijing's Zhongguancun district known as China's Silicon Valley two are especially well-known to IT researchers: Microsoft Research Asia 《中国科学院院刊(英文版)》2008,22(1):47-49
Among the galaxy of research and development organizations in northwest Beijing＇s Zhongguancun district, known as China＇s Silicon Valley, two are especially well-known to IT researchers： Microsoft Research Asia （MSRA）, and, within a few blocks on the other side of the street, the CAS Institute of Automation （CASIA）. While most people in Chinese scientific organizations strive to move to a large foreign counterpart, Dr. Stan Z. Li （LI Ziqing） moves against the stream. 相似文献
3.
SONG Jianlan 《中国科学院院刊(英文版)》2014,(4):282-284
<正>It is well known that when the genes of a cell are being expressed,the DNA chains unwind and transcribe their genetic information to RNA chains.One might take it for granted that the RNA chains are linear in shape,however,according to the latest results reported as an 相似文献
4.
《中国科学院院刊(英文版)》2005,19(2):74-75
Lichens are believed to play a pioneering role in transforming the earth surface when they appeared on land hundreds of million years ago, paving the way for the evolution of terrestrial plants and animals. But most habitats where lichens dominate,such as tundra, mountains, and deserts, have a very low chance of preserving fossils. Until recently the earliest known lichen fossils were discovered in 1995 by Thomas N.Taylor, a University of Kansas researcher, from 400 million-year old deposits in Scotland. 相似文献
5.
《国家科学评论(英文版)》2015,(4)
<正>Much atention has been given to three forms of scientiic misconducts known as falsiication,fabrication and plagiarism(FFP).Outright cases of FFP are rare,and once exposed,the consequences are severe.More frequent and hard to detect are questionable conducts in the gray zone,such as inappropriate data selection,analysis and presentation,misbehaviors in scientiic review and communication,and undue credit allocation in publications or other forms of research products.Some of these 相似文献
6.
1) The Compositae in Tibet so far known comprise 508 species and 88 genera,
which nearly amounts to one fourth of the total number of genera and one third of the
total number of species of Compositae in all China, if the number of 2290 species and 220
genera have respectively been counted in all China. In Tibet there are all tribes of Com-
positae known in China, and surprisingly, the large tribes in Tibetan Compositae are
also large ones in all China and the small tribes in Tibet are also small ones in all China.
Generally speaking, the large genera in Tibet are also large ones in all China and the
small genera in Tibet are likewise small ones in all China. In this sense it is reasonable to
say that the Compositae flora of Tibet is an epitome of the Compositae flora of all China.
In the Compositae flora of Tibet, there are only 5 large genera each containing 30
species or more. They are Aster, Artemisia, Senecio, Saussurea and Cremanthodium. And
5 genera each containing 10—29 species. They are Erigeron, Anaphalis, Leontopodium,
Ajania, Ligularia and Taraxacum. In addition, there are 77 small genera, namely 87%
of the total of Compositae genera in Tibet, each comprising 1—9 species, such as Aja-niopsis, Cavea and Vernonia, etc.
2) The constituents of Compositae flora in Tibet is very closely related to those of
Sichuan-Yunnan provinces with 59 genera and 250 species in common. Such a situation
is evidently brought about by the geographycal proximity in which the Hengtuang Shan
Range links southeastern and eastern Tibet with northern and northwestern Sichuan-
Ynnnan. With India the Tibetan Compositae have 59 genera and 132 species in common,
also showing close floristic relationships between the two regions. Apparently the floris-
tic exchange of Compositae between Tibet and India is realized by way of the mountain
range of the Himalayas. The mountain range of the Himalayas, including the parallel
ranges, plays a important role as a bridge hereby some members of the Compositae of
western or northern Central Asia and of the northern Africa or of western Asia have
migrated eastwards or southeastwards as far as the southern part of Fibet and northern
part of India, or hereby some Compositae plants of eastern and southeastern Asia or
Asia Media have migrated northwestwards as the northern part of Central Asia.
Some of the species and genera in common to both Tibet and Sinjiang indicate that
this weak floristical relationship between these regions is principally realized through two
migration routes: one migration route is by way of the Himalayas including the parallel
ranges to Pamir Plataeu and Tien Shan, or vice versa. The other migration route is by
way of northern Sinjiang to Mongolia, eastern Inner Mongolia, southwards to Gansu,
Qinghai (or western Sichuan), eastern Tibet up to the Himalayas, or vice versa.
However, Tibet is not entirely situated at a migration crossroad of the floral ele-
ments. An ample amount of the data shows that Compositae flora have a particular
capability of development in Tibet. of the total number of species of Tibetan Com-
positae, 102 species and 1 genus (Ajaniopsis Shih) are endemic. Besides, 8 genera are re-
gional endemics with their range extending to its neighbourhood. The higher percentage
of endemics at specific level than at generic in Tibetan Compositae may be a result of
active speciation in response to the new enviromental conditions created by the uplifting
of the Himalayas. The flora in Tibetan Plateau as a whole appears to be of a younger
age.
3) The uprising of the Himalayas and of the Tibetan Plateau accompanied by the
ultraviolet ray radiation, the microthermal climate and the high wind pressure has, no
doubt, played a profound influence upon the speciation of the native elements of Tibetan
Compositae. The recent speciation is the main trend in the development of the Com-positae flora native in Tibet in the wake of upheaval of the plateau. 相似文献
7.
《中国科学院院刊(英文版)》2017,(4)
正Previous studies in Ailao Mountains have recorded 30 species of epiphytic cyanolichens(lichens that contain cyanobacterial symbionts,known as the"blue-green algae")dominated by Lobar ia retigera.Although a great deal of work has been carried out to evaluate the biomass of this group and its contribution to ecosystem nitrogen(N)budgets,empirical studies are needed to confirm the N input responses by cyanolichens under climate change conditions(dry-hot stress)as well as to determine the 相似文献
8.
《中国科学院院刊(英文版)》2007,(2)
The National Basic Research Program (dubbed as the " 9 73 Program" is China's on-going national keystone basic research program, which was approved by the Chinese government in June 1997 and is organized and implemented by the Ministry of Science and Technology. The strategic objectives of the Program are to strengthen the original innovations and to address the important scientific issues concerning the national economic and social development at a deeper level and in a wider scope, so as to improve China's capabilities of independent innovations and to provide scientific support for the future development of the country. The followings are some of the" 9 73 projects" initiated in 2006 under the coordination of CAS scientists. 相似文献
9.
《中国科学院院刊(英文版)》2005,(2)
Lichens are believed to playa pioneering role in trans-forming the earth surfacewhen they appeared on land hun-dreds of million years ago, pavingthe way for the evolution of terres-trial plants and animals. But mosthabitats where lichens dominate,such as tundra, mountains, anddeserts, have a very low chance ofpreserving fossils. Until recently theearliest known lichen fossils werediscovered in 1995 by Thomas N.Taylor, a University of Kansasresearcher, from 400 million-year olddeposits in Sco… 相似文献
10.
1. Cohesion and Coherence According to Halliday and Hasan (1976: 4), cohesion is relations of meaning that exist within the text and that define it as a text. Cohe- sion occurs where the interpretation of some element in the discourse is dependent on that of another. Grammar and lexis are two means to realize the goal of cohesion. In other words, there are grammatical co- hesion and lexical cohesion. Coherence refers to the relationships, which link the meanings of utterances in a discourse … 相似文献
11.
《Journal of The Franklin Institute》2023,360(11):7501-7534
In this paper, we focus on an output secure consensus control issue for nonlinear multi-agent systems (MASs) under sensor and actuator attacks. Followers in an MAS are in strict-feedback form with unknown control directions and unknown dead-zone input, where both sensors and nonlinear characteristics of dead-zone in actuators are paralyzed by malicious attacks. To deal with sensor attacks, uncertain dynamics in individual follower are separated by a separation theorem, and estimation parameters are introduced for compensating and mitigating the influence from adversaries. The influence from actuator attacks are treated as a total displacement in a dead-zone nonlinearity, and an upper bound, as well as its estimation, is introduced for this displacement. The dead-zone nonlinearity, sensor attacks and unknown control gains are gathered together regarded as composite unknown control directions, and Nussbaum functions are utilized to address the issue of unknown control directions. A distributed secure consensus control strategy is thus developed recursively for each follower in the framework of surface control method. Theoretically, the stability of the closed-loop MAS is analyzed, and it is proved that the MAS achieves output consensus in spite of nonlinear dynamics and malicious attacks. Finally, theoretical results are verified via a numerical example and a group of electromechanical systems. 相似文献
12.
Ali Heydari 《Journal of The Franklin Institute》2017,354(11):4498-4518
The problem of optimal switching between different subsystems/configurations with minimum dwell time constraints is investigated in this study and a feedback solution, using the framework of approximate dynamic programming, is proposed. The method calls for a tuning stage in which parameters of a function approximator are tuned. Online control will then be conducted with a computational load as low as evaluating a few scalar-valued functions. Finite-horizon and infinite-horizon cost functions are investigated and convergence and stability are analyzed considering the presence of approximation errors. Moreover, the case of applying a full or partial constraint on the mode sequence, as well as having a mode-dependent minimum dwell time are investigated. Finally, performance of the scheme in handling different challenges is numerically evaluated through different examples. 相似文献
13.
Tourism firms operate in a competitive sector where innovating is often a condition for survival. This article presents a theoretical framework for understanding tourist firms’ innovative behaviour and innovation systems in tourism. The innovativeness of tourism firms and its determinants are investigated by analysing quantitative as well as qualitative data comparing Spain and Denmark. A taxonomy of tourism firms is suggested and the firms’ characteristics which influence their innovativeness are presented. Additionally, the role of innovation networks is discussed, as is the role of innovation systems. The article suggests that large size, professionalism, but also entrepreneurship among small tourism firms are important determinants of innovation. Varied innovation networks are another determinant as are supportive innovation systems. These determinants favour Spanish firms, which are more innovative than Danish ones. In the final section, policy recommendations are presented. 相似文献
14.
思想实验及其在科学发展中的作用 总被引：5，自引：0，他引：5
思想实验是有别于真实实验的一种理性思维活动。文章对思想实验进行了纵向的历史考察和横向的比较研究 ,分析了思想实验的基本特点和形态 ,进而阐述了思想实验在近代科学发展中的积极作用 ;强烈的质疑批判作用 ;深刻的探索创新作用 ;积极的认识发展作用。 相似文献
15.
贺州出土的青铜器量多而型美,在广西考古史上实属罕见。这些青铜器是凝固的历史,更是沉默的文化字符,蕴藏着贺州百越时期的民俗信仰、冶炼技术等诸多文化元素。贺州青铜器是新石器时代模制技术与金属采冶、浇铸技术相结合的集大成者,体现了百越精神的继承与创新。 相似文献
16.
专利产业化基地是促进我国自主知识产权转化的新型服务平台，其构建和运作模式尚处于探索阶段。现作为试点的实体基地在运作过程中出现组织构架上的诸多问题，据此引入虚拟化的概念，并对此新模式在我国推行的可行性进行了分析研究，并以重庆为例设计具体运作方案。 相似文献
17.
The structure of a retrospective information retrieval system that uses equifrequent word or text fragments is described, and its advantages over word oriented systems are mentioned briefly. Word fragments are proposed as retrieval elements, and a discussion is given of the changes required in order to process a query. Some necessary modifications in the treatment of logical operators are described, and two conditions are postulated as necessary for the successful operation of the system. Aspects of query processing are illustrated by experimental results obtained from single and two-term queries applied to a portion of the MARC tapes. 相似文献
18.
《Information processing & management》2016,52(6):1074-1085
Literature shows interdisciplinary research as an essential driver for innovation. Ideas that are used as a starting point for this research are of an interdisciplinary nature because they combine aspects from different disciplines. The identification of interdisciplinary ideas at an early stage enables the start of interdisciplinary research and thus, it enables advances to be made in the innovation process. We propose a new methodology that combines semantic clustering and classification to estimate the interdisciplinary nature of ideas from a set of given ideas. The set is created automatically by use of an existing idea mining approach. Ideas from this set are semantically clustered to obtain concepts that are latent in the data. The relationship between each concept and each discipline pair from a set of given disciplines is calculated. Based on the degree of relationship, concepts are used to represent the interdisciplinary field spanned by the two disciplines. The ideas standing behind these concepts are identified as interdisciplinary ideas. As a result, the proposed methodology enables an estimation of the interdisciplinary nature of given ideas. The results might be helpful for researchers as well as for decision makers in the field of innovation management. 相似文献
19.
D. P. Neupane S. Majhi L. Chandra S. Rijal Nirmal Baral 《Indian journal of clinical biochemistry : IJCB》2008,23(1):95-97
A glutathione redox cycle is a major antioxidant defense system for the detoxification of reactive oxygen species within erythrocytes.
Reactive oxygen species such as superoxide anions, hydrogen peroxide and hydroxyl radicals are generated as a host defense
mechanism for killing of engulfed Leishmania donovani, a causative agent of visceral leishmaniasis, are capable of damaging
lipids and other biomolecules when produced in excess. Erythrocytes are most vulnerable to Reactive oxygen species. In present
study we aimed to evaluate erythrocyte reduced glutathione (GSH) levels as an antioxidant and erythrocyte malondialdehyde
(MDA) as a marker of lipid peroxidation. The study included twenty-five Visceral leishmaniasis patients and they were followed
up after their complete chemotherapy with antileishmanial drugs (sodium stibogluconate) for 30 days. Forty six age and sex
matched healthy individuals were taken as controls. GSH levels in erythrocytes of visceral leishmaniasis patients were increased
in spite of significant increased erythrocyte MDA as compared to controls. Whereas erythrocyte GSH and MDA levels of follow
up patients were decreased as compared to patients before treatment groups. We concluded that visceral leishmaniasis patients
are in oxidative stress which most likely induces the endogenous antioxidant such as GSH or its poor utilization by cells. 相似文献
20.
Hugo T.M. Kussaba João Y. Ishihara Leonardo R.A.X. Menezes 《Journal of The Franklin Institute》2019,356(6):3797-3810
This paper proposes a robust version of the unscented transform (UT) for one-dimensional random variables. It is assumed that the moments are not exactly known, but are known to lie in intervals. In this scenario, the moment matching equations are reformulated as a system of polynomial equations and inequalities, and it is proposed to use the Chebychev center of the solution set as a robust UT. This method yields a parametrized polynomial optimization problem, which in spite of being NP-Hard, can be relaxed by some algorithms that are proposed in this paper. 相似文献