胡鞍钢：五大资本推动中国发展

一个国家或者一个企业发展的基础我们称之为一个国家或一个企业的资本，以往认为资本主要是物质资本。世界银行在2000年首次提出，一个国家或者一个企业，它的发展是依靠三大资本，即所谓人力资本、物质资本和自然资本。我们对这个分析框架做了一个改进，增加了两大资本：一个叫“国际资本”，反映一个国家、地区，或一个企业如何有效率地利用全球资本；另一个是“知识资本”。因为我们认为它是一个国家、一个地区或一个企业在21世纪竞争中最重要的资本。     

有向图中不相交的准核

有向图D的一个顶点集X被称为D的一个核,如果X是一个独立集并且X之外的每一个点都能经一步到达置有向图D的一个顶点集X被称为D的一个准核,如果X是一个独立集并且X之外的每一个点都能经一步或两步到达X．在这篇文章中,我们给出了一个有向图有一对不相交的准核的一个必要条件和若干充分条件．     

金融危机进入第四阶段

目前的这场全球金融危机,仍在按其内在逻辑的必然性向前推进、扩展和深化,在一个接一个的国家捅出了一个接一个的破洞,从一个阶段到更加深入     

信息系统诱导的信息代数

通过对信息系统诱导一个信息代数进行新的刻画, 得到一个信息系统可以诱导一个信息代数, 而不再需要附加条件, 并且得到一个连续的信息系统可得一个连续的信息代数, 一个紧信息系统可得一个紧信息代数.     

招商九大误区

什么是招商曾经有一个企业的老总开玩笑地用拆字法解释说,招商的“招”字很有意思,左边是一个提手,右边上面是一个刀,下面是一个口。所以招商就是一个人提着一把刀站在门口,凡是进去的企业来一个宰一个,来两个宰一双。     

创新无畏——杭州城市性格解读

我们常常用“思路决定出路”来激励一个人甚至一个单位、一个区域、一个国家的不断奋进,但一直以来很少用“性格决定命运”来考量一个单位、一个区域、一座城市的发展路径和未来蓝图。     

图的上可嵌入性的一些表征

提供了这样一个事实：在一个简单图Ｇ和它的补Ｇ￣Ｃ中，总有一个是上可嵌入的。同时，也给出了一个图不是可嵌入的一个结构特征。     

从《不了情》到《色·戒》六十春秋铸传奇——将名字投影在银幕上的张爱玲

她是一个梦，一个属于旧上海纸醉金迷的梦。 她是一个谜，一个一生漂泊、结局未知的谜。     

九宫填数

在一个漆黑的夜里，一个矮个、一个高个、一个胖子、一个老人、一个瘸子5个人要经过一座狭窄而且没有护拦的桥。由于天黑．过桥时需要借助手电筒。不巧的是，5个人只带了一只手电筒。     

秦汉兴衰：文化选择的决定作用

一个国家、一个民族的发展与振兴,需要综合实力来支撑。从秦汉兴衰的历史嬗变中可看出,文化的取舍,决定着一个民族、一个王朝、一个国家的根本命运。     

不同轮伐期对巨尾桉人工林碳固存的影响

【目的】深入探讨不同轮伐期对巨尾桉人工林碳固存的影响,为从应对全球气候变化的视角确定合理轮伐期提供理论依据。【方法】以轮伐期为短(7a)、中(13a)和长周期(21a)的巨尾桉人工林为研究对象,通过对不同轮伐期桉树林分生物量、碳固存、年平均固碳量的分析,揭示不同轮伐期对桉树林分碳固存的影响。【结果】巨尾桉人工林的生物量碳随着轮伐期的延长而逐渐增加,由7a轮伐期的(75.81±5.12)t·C/hm~2增至13a轮伐期的(180.11±19.97)t·C/hm~2以及21a轮伐期的(192.08±16.50)t·C/hm~2,方差分析表明,13a和21a轮伐期的总生物量碳显著高于7a轮伐期,而13a和21a轮伐期之间的差异不显著。巨尾桉人工林土壤有机碳随轮伐期延长而显著降低,由7a轮伐期的(89.99±0.35)t·C/hm~2、13a轮伐期的(85.42±0.76)t·C/hm~2下降到21a轮伐期的(74.64±0.24)t·C/hm~2。7~13a仍是巨尾桉人工林固碳能力迅速增长期,年平均总生物量碳由7a时的10.78t·C/(hm~2·a)迅速提高到13a的19.54t·C/(hm~2·a),增长81%;21a时巨尾桉人工林进入固碳能力下降期,年平均总生物量碳降至3.78t·C/(hm~2·a),固碳能力只是13a的19.34%。【结论】在南亚热带,巨尾桉人工林的最佳轮伐期确定在13a左右较为适宜,这与经济效益的最大化一致。     

Pollen-recorded climate changes between 13.0 and 7.0 ^14C ka BP in southern Ningxia, China

A pollen record from Haiyuan section in the southern part of Ningxia revealed a detailed history of vegetation variation and associated climate changes during the period from~13.0 to~7.0 14 C ka BP.A steppe landscape under a moderately dry(and probably cool)condition(~12.7-~12.1 14 C ka BP)was replaced by a coniferous forest dominating the landscape under a generally wet climate from~12.1 to ~11.01 4C ka BP.This generally wet period,corresponding to the European B?lling/All?rod period,can be divided into three stages:a cool and wet stage between~12.1 and~11.4 14 C ka BP,a mild and rela- tively dry stage between~11.4 and~11.2 14 C ka BP,and a mild and wet stage between~11.2 and~11.0 14 C ka BP.The coniferous forest-dominated landscape was then deteriorated into steppe landscape (~11.0-~10.6 14 C ka BP)and further into a desert steppe landscape from~10.6 to~9.8 14 C ka BP,being correspondent to the European Younger Dryas period.After a brief episode of a cool and wet climate (~9.8-~9.6 14 C ka BP),a relatively mild and dry condition prevailed during the early Holocene(~9.6- ~7.6 14 C ka BP)and then a warm and humid climate started the mid-Holocene(~7.6-~7.2 14 C ka BP).     

Hilbert空间连续K－框架的冗余与扰动性

基于连续K-框架的定义,给出了Hilbert空间连续K-框架的两个等价刻画.在连续K-框架中挖去部分元素还构成连续K-框架的两个充分条件和不构成连续K-框架的一个充分条件,利用合成算子和两个连续Bessel映射的有界线性算子SF,G去刻画连续K-框架.最后讨论Hilbert空间连续K-框架的扰动.     

一类多元Hermite型插值的离散化问题

利用离散逼近算法理论,研究一类特殊的多元Hermite型插值的离散化问题,即将给定的Hermite型插值问题离散为一列Lagrange插值问题的极限.当Hermite型插值问题的插值条件对应一个二阶微分不变子空间时,利用其空间的结构属性,给出该问题在离散逼近算法思想下可被离散的充要条件,该条件对应的非线性方程组规模较小...     

亏秩线性方程组的PSD迭代解法

将亏秩线性方程组Ax=b增广为以方阵Â为系数矩阵的4×4块线性方程组Âη=b´,再对A进行次正则PSD分裂,得到PSD迭代法半收敛的一个充要条件。最后给出求方程组Ax=b范数最小的最小二乘解的方法并以实例说明, 其中A∈C^m×n,b∈C^m,b´∈C ^m+n     

A bizarre <Emphasis Type="Italic">Palissya</Emphasis> ovulate organ from Upper Triassic strata of the Zixing coal field,Hunan Province,China

Palissya,a little-known reproductive organ with a long history,is recorded from China and Asia for the first time.A new species,Palissya hunanensis(sp.nov.) ,is described from the Upper Triassic Rhaetican strata of the Zixing coal field of Hunan Province.The ovulate cone has a compound shoot system that consists of a main axis and many helically-arranged axillary structures re-ferred to as female dwarf shoots,each of which is subtended by a bract.Despite a superficial similarity,P.hunanensis differs from the typical species P.sphenolepis(Braun) Nathorst in a number of subtle but consistent features:the cone is much smaller and narrower,the bracts are much thinner,there are fewer pairs of cup-like seed scales,and the seed scales are adaxially attached to a thick axis rather than to bracts.These traits are all distinctly different from other species of the genus.Moreover,SEM obser-vation of the new species reveals morphological features of the seed scales and seeds and details of the female dwarf shoot;sig-nificantly increases our knowledge of Palissya;and provides new evidence that it is a conifer.Palissya is related to the Lower Permian Lebowskia,a voltzian conifer bearing ovuliferous structures similar to the bract plus dwarf-shoot organization of Palis-sya.Palissya-type conifers probably grew in specialized marine-continent habitats,unlike most other extant and extinct conifers that grow in drier upland environments.     

Effect of Ce addition on hot tearing behavior of AZ91 alloy

A small amount of cerium (below 1.0 wt%) addition to AZ91 alloy have been investigated on the hot tearing susceptibility (HTS) at a cooling rate of 1.5Ks^?1. The HTS increased to a maximum value with a cerium addition of 0.6 wt% and then decreased to a stable status as cerium was gradually added. Due to high chemical activity, cerium into the melts can react with aluminum to form an Al₁₁Ce₃ intermetallic compound. X–ray diffraction results also confirmed the existence of Al₁₁Ce₃. The Al₁₁Ce₃ increased with the presence of the needle-like and block morphology. As cerium levels increased, the amount of Mg₁₇Al₁₂ decreased. The variations between Mg₁₇Al₁₂ and Al₁₁Ce₃ resulted in a similar normal distribution of the HTS in AZ91 alloy. The findings were further verified through the microstructure evolution and the surface morphology of fracture.     

Subcellular localization and inductive expression of the dsRNA-dependent protein kinase PKR from Japanese flounder, Paralichthys olivaceus

The double-stranded RNA (dsRNA)-dependent protein kinase (PKR) belongs to the eIF2α kinase family and plays a critical role in interferon (IFN)-mediated antiviral response. Recently, in Japanese flounder (Paralichthys olivaceus), a PKR gene has been identified. In this study, we showed that PoPKR localized to the cytoplasm, and the dsRNA-binding motifs (dsRBMs) played a determinative role in protein localization. In cultured FEC cells, PoPKR was detected at a low level of constitutive expression but was highly induced after treatment with UV-inactivated grass carp hemorrhagic virus, active SMRV and Poly I:C although with different expression kinetics. In flounder, PoPKR was ubiquitously distributed in all tested tissues, and SMRV infection resulted in significant upregulation at mRNA and protein levels. In order to reveal the role of PoPKR in host antiviral response, its expression upon exposure to various inducers was characterized and further compared with that of PoHRI, which is another eIF2α kinase of flounder. Interestingly, expression comparison revealed that all inducers stimulated upregulation of PoHRI in cultured flounder embryonic cells and fish, with a similar kinetics to PoPKR but to a less extent. These results suggest that, during antiviral immune response, both flounder eIF2α kinases might play similar roles and that PoPKR is the predominant kinase.     

Analysis of electromagnetic pressure on thin plate melt

An equation used to calculate electromagnetic pressure for confining and shaping a plate-form melt with small or medium thickness is brought forward. The equation gives a precise relationship between electromagnetic pressure factor p and current frequency f, melt thickness a and electromagnetic parameter μγ . The main results can be summarized as follows: ( i ) As the f, a and μγ are large enough, causing the ratio of melt thickness to current skin depth a/ S to be larger than 2.2, p will be a constant ( p = 1) and the electromagnetic pressure can be calculated with Pm = B2/2λ. ( ii ) As the f, a, and μγare not large enough, and the ratio a/ 8 is less than 2.2, p is no longer a constant but changes from 1 to 0 with the decrease of a/δ. In this case, the value of electromagnetic pressure is determined not only by magnetic flux density 8 but also by the current frequency f, melt thickness a and electromagnetic parameter μγ.     

Modulation of synchronous calcium oscillations in hippocampal neurons by photostimulation of astrocytes with femtosecond laser

A large body of evidence indicates that astrocytes play an important role in a range of brain functions through calcium (Ca²⁺) signaling. Experimentally evoking Ca²⁺ signaling is a useful technique for investigating the functions of astrocytes. However, conventional stimulation methods typically have poor spatio-temporal precision, and some are invasive. Our group has developed a technique to overcome these problems, in which astrocytes are photostimulated with a femtosecond laser. In the current study, we applied this method to a hippocampal neural network to explore astrocytic functions in detail. The results revealed that applying photostimulation to astrocytes in a cultured hippocampal astrocyte-neuron network caused the following changes: (i) Synchronous Ca²⁺ oscillations in neurons were induced; (ii) spontaneous Ca²⁺ synchrony instantaneously emerged; and (iii) high-frequency spontaneous Ca²⁺ synchrony was regulated. Thus, astrocytic Ca²⁺ signaling evoked by photostimulation was found to modulate synchronous Ca²⁺ oscillations in hippocampal neurons. We propose that photostimulation with a femtosecond laser will serve as a powerful tool in investigating astrocytic functions at the network level.