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1.
前  言  在新世纪开初 ,欣逢《植物生理学通讯》创刊 5 0周年。本刊新组建的编委会决定循 4 0周年时的前例 ,也举行一次活动(包括出版“特辑”和召开座谈会 )。于是我们约请了一些人士撰写了纪念文稿 ,同时也收到了一些自发来稿 ,编辑了这个“特辑”。作者从九十高龄的娄成后先生 ,直到年轻的在读研究生 ,他们在文章中高度评价了本刊的作用和成就 ,同时也对本刊寄予了殷殷厚望 ,可以说代表了当今植物生理学界几代人的心声。这里 ,谨向他们表示由衷的感谢 !文稿中大都冠有“祝贺《植物生理学通讯》创刊 5 0周年”的副标题 ,为避免重复 ,一律舍去了。还有几篇文章题目雷同 ,我们作了改动。并此说明。———编者  相似文献   

2.
2009年5月,繁花烂漫的季节,高等教育出版社迎来了55周年华诞,《生命世界》杂志也走过了5年不平凡的历程。我们出版的高质量的教材和学术著作为我国的生命科学人才培养和学科建设发挥了积极的重要作用,受到了广大师生和科研人员的欢迎。《生命世界》在传播生命科学知识、提高大众科学素养方面起到了很好的作用,全国人大常委会副委员长、中国科学院院长路甬祥院士和全国人大常委会副委员长、中国科协主席、  相似文献   

3.
2009年5月,繁花烂漫的季节,高等教育出版社迎来了55周年华诞,《生命世界》杂志也走过了5年不平凡的历程。我们出版的高质量的教材和学术著作为我国的生命科学人才培养和学科建设发挥了积极的重要作用,受到了广大师生和科研人员的欢迎。《生命世界》在传播生命科学知识、提高大众科学素养方面起到了很好的作用,全国人大常委会副委员长、中国科学院院长路甬祥院士和全国人大常委会副委员长、中国科协主席、  相似文献   

4.
生态条件的多样性变化对蜜蜂生存的影响   总被引:1,自引:0,他引:1  
侯春生  张学锋 《生态学报》2011,31(17):5061-5070
蜜蜂在整个生态系统中起着重要的传花授粉作用,是生态链中不可或缺的物种。随着现代农业的发展,蜜蜂赖以生存的环境遭到破坏,继而引发蜜蜂数量大幅减少,影响了蜂种的生存与可持续发展。总结了近年来生态条件的变化,归纳了影响蜜蜂生存的主要因素,分析了蜜蜂生存艰难的原因,提出了蜜蜂生存的关键问题,并展望了未来维持蜜蜂强群的主要研究方向。  相似文献   

5.
降脂红曲的菌学性质及化学成分的分析   总被引:4,自引:0,他引:4  
本文对No.4降脂红曲的生理特性进行了分析,测定了其一般的化学成分,将No.4红曲米的色调和色价与其它红曲米进行了对比,确定了该红曲的最适培养条件,制定了No.4红曲米的质量标准,并验证了它可作为糖化酶的生产菌。  相似文献   

6.
啤酒酵母的开发应用及其制代可可粉的研究   总被引:1,自引:0,他引:1  
本文介绍了啤酒酵母营养的成分和医用价值,概述了国内外开发应用啤酒酵母的研究功态,研究了用啤酒酵母加工代可可粉的工艺路线和方法,同时回收了啤酒,测定了代可可粉的营养成分,并用之加工巧克力和可可饮料,结果表明,其效果与天然可可粉类同。  相似文献   

7.
试图在分子水平上解释生命现象的分子生物学从其工程学角度派生出了生物工程学,1972年,DNA重组技术取得了引人注目的成功。自那以后,这二方面就开始了惊人的发展,在这里,让我们来回顾一下过去的业迹。  相似文献   

8.
本文就粗品肝素钠生产的原料控制、硬件设施、管理和环保等方面进行了论述,介绍了一些改进的方法和措施,并就该方面的一些问题进行了探讨,提出了解决的方法.  相似文献   

9.
前  言  在新世纪开初 ,欣逢《植物生理学通讯》创刊 5 0周年。本刊新组建的编委会决定循 4 0周年时的前例 ,也举行一次活动(包括出版“特辑”和召开座谈会 )。于是我们约请了一些人士撰写了纪念文稿 ,同时也收到了一些自发来稿 ,编辑了这个“特辑”。作者从九十高龄的娄成后先生 ,直到年轻的在读研究生 ,他们在文章中高度评价了本刊的作用和成就 ,同时也对本刊寄予了殷殷厚望 ,可以说代表了当今植物生理学界几代人的心声。这里 ,谨向他们表示由衷的感谢 !文稿中大都冠有“祝贺《植物生理学通讯》创刊 5 0周年”的副标题 ,为避免重复 ,一律舍去了。还有几篇文章题目雷同 ,我们作了改动。并此说明。———编者  相似文献   

10.
为提高医学免疫学实验教学质量,培养学生创新能力,对本校2015级、2016级及2017级5年制临床医学专业医学免疫学实验教学课程进行了改革和探索。在基础验证性实验的基础上,开展了综合设计性实验,并试行了探索性创新性实验及开放性科研性实验。通过改革使学生成为教学过程的主体,充分激发学生的学习热情,不仅培养了学生的动手能力,更提高了他们交流合作及分析和解决问题的能力,从而推进了学生创新能力的培养。  相似文献   

11.
The concept of “global health” that led to the establishment of the World Health Organization in the 1940s is still promoting a global health movement 70 years later. Today’s global health acts first as a guiding principle for our effort to improve people’s health across the globe. Furthermore, global health has become a branch of science, “global health science,” supporting institutionalized education. Lastly, as a discipline, global health should focus on medical and health issues that: 1) are determined primarily by factors with a cross-cultural, cross-national, cross-regional, or global scope; 2) are local but have global significance if not appropriately managed; and 3) can only be efficiently managed through international or global efforts. Therefore, effective global health education must train students 1) to understand global health status; 2) to investigate both global and local health issues with a global perspective; and 3) to devise interventions to deal with these issues.  相似文献   

12.
Most neurons in cortical area MT (V5) are strongly direction selective, and their activity is closely associated with the perception of visual motion. These neurons have large receptive fields built by combining inputs with smaller receptive fields that respond to local motion. Humans integrate motion over large areas and can perceive what has been referred to as global motion. The large size and direction selectivity of MT receptive fields suggests that MT neurons may represent global motion. We have explored this possibility by measuring responses to a stimulus in which the directions of simultaneously presented local and global motion are independently controlled. Surprisingly, MT responses depended only on the local motion and were unaffected by the global motion. Yet, under similar conditions, human observers perceive global motion and are impaired in discriminating local motion. Although local motion perception might depend on MT signals, global motion perception depends on mechanisms qualitatively different from those in MT. Motion perception therefore does not depend on a single cortical area but reflects the action and interaction of multiple brain systems.  相似文献   

13.
Sleep spindles occur thousands of times during normal sleep and can be easily detected by visual inspection of EEG signals. These characteristics make spindles one of the most studied EEG structures in mammalian sleep. In this work we considered global spindles, which are spindles that are observed simultaneously in all EEG channels. We propose a methodology that investigates both the signal envelope and phase/frequency of each global spindle. By analysing the global spindle phase we showed that 90% of spindles synchronize with an average latency time of 0.1 s. We also measured the frequency modulation (chirp) of global spindles and found that global spindle chirp and synchronization are not correlated. By investigating the signal envelopes and implementing a homogeneous and isotropic propagation model, we could estimate both the signal origin and velocity in global spindles. Our results indicate that this simple and non-invasive approach could determine with reasonable precision the spindle origin, and allowed us to estimate a signal speed of 0.12 m/s. Finally, we consider whether synchronization might be useful as a non-invasive diagnostic tool.  相似文献   

14.
An autonomous periodic behaviour may correspond to a local or global limit cycle. If the cycle is local, the mathematical analysis is fairly easy upon linearizing about a singular point, but there are few mathematical methods for the determination of global limiting cycles. A periodic motion has a priori a 50% chance of being global. This paper describes a method of predicting certain types of global limit cycles. The application of this procedure indicates that there are plenty of biochemical systems with stable singular points but nevertheless oscillatory.  相似文献   

15.
This paper addresses the global existence and global asymptotic behaviour of positive solutions to a non-autonomous Nicholson's blowflies model with delays. By using a novel approach, sufficient conditions are derived for the existence and global exponential convergence of positive solutions of the model without any restriction on uniform positiveness of the per capita dead rate. Numerical examples are provided to illustrate the effectiveness of the obtained results.  相似文献   

16.
In this paper, we consider the concepts of evolutionarily stable strategy (ESS), neighborhood invader strategy (NIS) and global invader strategy (GIS) in single species with frequency-dependent interactions. We find some general relationships among the three concepts in matrix games. The main conclusion is that ESS and NIS are equivalent to each other and are both equivalent to local superiority; a strategy with global superiority must be a GIS; a GIS may not be equivalent to its global superiority in games with more than two players; and in any two-player matrix game a GIS is just equivalent to its global superiority. In two-player games, globally asymptotic stability in the replicator dynamics has also been shown. Equivalent conditions for the three concepts stated by payoff comparisons are given and are applied to examples involved.  相似文献   

17.
研究了一类具多比例时滞细胞神经网络的全局指数周期性与稳定性.通过变换y(t)=x(e~t)将具多比例时滞的细胞神经网络变换成具常时滞变系数的细胞神经网络,利用一些分析技巧与构造合适的Lyapunov泛函,得到系统的周期解存在唯一且全局指数周期的时滞依赖的充分条件,判断方法简单易验证.并给出了两个例子及其数值仿真结果以支持所得结论.  相似文献   

18.
Proteins are not rigid molecules, but exhibit internal motions on timescales ranging from femto- to milliseconds and beyond. In solution, proteins also experience global translational and rotational motions, sometimes on timescales comparable to those of the internal fluctuations. The possibility that internal and global motions may be directly coupled has intriguing implications, given that enzymes and cell signaling proteins typically associate with binding partners and cellular scaffolds. Such processes alter their global motion and may affect protein function. Here, we present molecular dynamics simulations of extreme case scenarios to examine whether a possible relationship exists. In our model protein, a ubiquitin-like RhoGTPase binding domain of plexin-B1, we removed either internal or global motions. Comparisons with unrestrained simulations show that internal and global motions are not appreciably coupled in this single-domain protein. This lack of coupling is consistent with the observation that the dynamics of water around the protein, which is thought to permit, if not stimulate, internal dynamics, is also largely independent of global motion. We discuss implications of these results for the structure and function of proteins.  相似文献   

19.
Aim Some nations, and the International Maritime Organization, are moving towards requirements for managing ballast water to reduce the number of alien species transported and released. These and other measures will be most efficient when targeted at ships posing the greatest risks. Here, we analyse world‐wide ship movements and port environmental conditions to explore how these risk components differ across arriving ships. Location Global, with a case study of the Laurentian Great Lakes. Methods We gathered salinity and temperature data for all global shipping ports, and data for all global ship movements during a 12 ‐month period. We applied these data to the Laurentian Great Lakes to determine which global ports may donate new species to the Great Lakes via ship traffic, and which are most environmentally similar to the Great Lakes. Results We show that ships regularly travel to the Great Lakes from all major coastal, and many inland, regions of the world. Most global ports, and thus the species in them, are separated from the Great Lakes by no more than two ship voyages. Combined with a measure of environmental similarity among global ports, we identify ship routes likely to transport species adapted for survival in the Great Lakes and global regions that may be the source of increasing future invasions. Main conclusions The Great Lakes account for a small fraction of global shipping yet are closely connected to all other ports, and the species in them, by the shipping network. Our methods and data allow risks from individual ships to be ranked so that management activities can be targeted at ships most likely to introduce new invaders. Because our data sets are global, they could be applied to ship arrivals at any global port.  相似文献   

20.
Soil respiration (Rs) is a major pathway by which fixed carbon in the biosphere is returned to the atmosphere, yet there are limits to our ability to predict respiration rates using environmental drivers at the global scale. While temperature, moisture, carbon supply, and other site characteristics are known to regulate soil respiration rates at plot scales within certain biomes, quantitative frameworks for evaluating the relative importance of these factors across different biomes and at the global scale require tests of the relationships between field estimates and global climatic data. This study evaluates the factors driving Rs at the global scale by linking global datasets of soil moisture, soil temperature, primary productivity, and soil carbon estimates with observations of annual Rs from the Global Soil Respiration Database (SRDB). We find that calibrating models with parabolic soil moisture functions can improve predictive power over similar models with asymptotic functions of mean annual precipitation. Soil temperature is comparable with previously reported air temperature observations used in predicting Rs and is the dominant driver of Rs in global models; however, within certain biomes soil moisture and soil carbon emerge as dominant predictors of Rs. We identify regions where typical temperature‐driven responses are further mediated by soil moisture, precipitation, and carbon supply and regions in which environmental controls on high Rs values are difficult to ascertain due to limited field data. Because soil moisture integrates temperature and precipitation dynamics, it can more directly constrain the heterotrophic component of Rs, but global‐scale models tend to smooth its spatial heterogeneity by aggregating factors that increase moisture variability within and across biomes. We compare statistical and mechanistic models that provide independent estimates of global Rs ranging from 83 to 108 Pg yr?1, but also highlight regions of uncertainty where more observations are required or environmental controls are hard to constrain.  相似文献   

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