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931.
A dragonfly wing consists of membranes and both longitudinal and cross veins. We observed the microstructure cross-section
at several locations in the dragonfly wing using environmental scanning electron microscopy (ESEM). The organic nature of
the junction between the vein and the membrane was clearly identifiable. The membrane was divided into two layers, the upper
epidermis and the lower epidermis. These layers extend around the sandwich structure vein, and combine with the adjacent membrane
at a symmetrical location along the vein. Thus, we defined this as an organic junction between the vein and the membranes.
The organic junction is able to form a tight corrugation angle, which dramatically increases both the warping rigidity and
the strength of the wing, but not the torsional rigidity. The torsional deformation is primarily controlled by the microstructure
of the longitudinal veins, and is based on the relative rotation angle between the epidermal layer and the inner layer of
the vein that forms the zigzag section. 相似文献
932.
Lucas Matt Stylianos Michalakis Franz Hofmann Verena Hammelmann Andreas Ludwig Martin Biel Thomas Kleppisch 《Cellular and molecular life sciences : CMLS》2011,68(1):125-137
Neuronal hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are known to modulate spontaneous activity, resting
membrane potential, input resistance, afterpotential, rebound activity, and dendritic integration. To evaluate the role of
HCN2 for hippocampal synaptic plasticity, we recorded long-term potentiation (LTP) in the direct perforant path (PP) to CA1
pyramidal cells. LTP was enhanced in mice carrying a global deletion of the channel (HCN2−/−) but not in a pyramidal neuron-restricted knockout. This precludes an influence of HCN2 located in postsynaptic pyramidal
neurons. Additionally, the selective HCN blocker zatebradine reduced the activity of oriens-lacunosum moleculare interneurons
in wild-type but not HCN2−/− mice and decreased the frequency of spontaneous inhibitory currents in postsynaptic CA1 pyramidal cells. Finally, we found
amplified LTP in the PP of mice carrying an interneuron-specific deletion of HCN2. We conclude that HCN2 channels in inhibitory
interneurons modulate synaptic plasticity in the PP by facilitating the GABAergic output onto pyramidal neurons. 相似文献
933.
本文概括了控制精子正常产生的诸多候选基因在染色体上的定位、演化及其编码的 RNA 结合蛋白与人类男性精子发生之间关系研究方面的最新进展,为人类男性不育症的治疗和计划生育的顺利推行奠定了坚实的理论基础并展示出光明的前景。 相似文献
934.
Laurent Nottale 《Foundations of Science》2011,16(4):307-309
We give a “direction for use” of the scale relativity theory and apply it to an example of spontaneous multiscale integration
including four embedded levels of organization (intracellular, cell, tissue and organism-like levels). We conclude by an update
of our analysis of the arctic sea ice melting. 相似文献
935.
John Hamilton 《系统科学与系统工程学报(英文版)》2007,16(4):414-423
Modeling a business to match its customer perceived (and customer desired) outcomes, remains an on-going task. This paper considers shows how a service value networks (SVNs) approach may be engaged to model, and deliver, understanding of the front-end business and its direct engagement with its immediate (or front-end) customers. These front-end customers may be either: (1) its off-line, in-store customers - engaging directly with the business sales staff (or representative), or-(2) its on-line, virtual customers - engaging with the business via internet or remote access. In this situation, both the business, and the customer draw upon their respective viewpoints, and both sides influence the interaction. External to these business and customer influences are additional factors that capture the immediate and broader global effects - termed environmental effects. These three business-customer engagement areas of influence are captured by a SVN SEM approach.
Without a business-customer encounter of some kind the likelihood of a services business, and a prospecting customer, successfully engaging in an exchange process is reduced. This exchange may be a physical, and/or services exchange, and/or an information and/or ideas exchange. To the business, this encounter is, in effect, a trade, and as a result, the business targets acquiring an economic exchange that will ultimately deliver a net positive economic outcome. To the customer, external and internal information feeds, servicing, perceived value, and satisfaction, are key encounter drivers. SVNs offers a new way to understand the business-customer encounter, and to then utilize this acquired knowledge to either: (1) build a strategic management model, or (2) reengineer its business networks, and to then create a re-positioned, more customer-aligned business operation - one that is capable of delivering win - win, competitive business-customer solutions. 相似文献
Without a business-customer encounter of some kind the likelihood of a services business, and a prospecting customer, successfully engaging in an exchange process is reduced. This exchange may be a physical, and/or services exchange, and/or an information and/or ideas exchange. To the business, this encounter is, in effect, a trade, and as a result, the business targets acquiring an economic exchange that will ultimately deliver a net positive economic outcome. To the customer, external and internal information feeds, servicing, perceived value, and satisfaction, are key encounter drivers. SVNs offers a new way to understand the business-customer encounter, and to then utilize this acquired knowledge to either: (1) build a strategic management model, or (2) reengineer its business networks, and to then create a re-positioned, more customer-aligned business operation - one that is capable of delivering win - win, competitive business-customer solutions. 相似文献
936.
“隐秀”是“任笔”的一个突出特点。“隐”在昉文中既表现为命意上的“深衷内朗”,又表现为属辞上的“潜气内转”;“秀”是指防文秀句中所体现出来的意秀、情秀和辞秀。昉文的“隐秀”特征在《为齐明帝让宣城郡公第一表》一文中得到了集中体现。 相似文献
937.
1. Introduction The Capacitated Arc Routing Problem(CARP) is defined on an undirected network inwhich a fleet of identical vehicles with limitedcapacity is based at a depot node. Each edge hasa non-negative traversal cost and can betraversed any number… 相似文献
938.
孙龙 《科技情报开发与经济》2008,18(22):209-210
分析了井下开延巷道施工采用全断面一次光爆成巷技术的条件,阐明了其技术参数的选取原则,并提出了保证施工质量的具体措施。 相似文献
939.
Tilman Sauer 《Archive for History of Exact Sciences》2008,62(1):1-22
Einstein’s early calculations of gravitational lensing, contained in a scratch notebook and dated to the spring of 1912, are
reexamined. A hitherto unknown letter by Einstein suggests that he entertained the idea of explaining the phenomenon of new
stars by gravitational lensing in the fall of 1915 much more seriously than was previously assumed. A reexamination of the
relevant calculations by Einstein shows that, indeed, at least some of them most likely date from early October 1915. But
in support of earlier historical interpretation of Einstein’s notes, it is argued that the appearance of Nova Geminorum 1912
(DN Gem) in March 1912 may, in fact, provide a relevant context and motivation for Einstein’s lensing calculations on the
occasion of his first meeting with Erwin Freundlich during a visit in Berlin in April 1912. We also comment on the significance
of Einstein’s consideration of gravitational lensing in the fall of 1915 for the reconstruction of Einstein’s final steps
in his path towards general relativity. 相似文献
940.