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The design of good notation is a cause that was dear to Charles Babbage’s heart throughout his career. He was convinced of the “immense power of signs” (1864, 364), both to rigorously express complex ideas and to facilitate the discovery of new ones. As a young man, he promoted the Leibnizian notation for the calculus in England, and later he developed a Mechanical Notation for designing his computational engines. In addition, he reflected on the principles that underlie the design of good mathematical notations. In this paper, we discuss these reflections, which can be found somewhat scattered in Babbage’s writings, for the first time in a systematic way. Babbage’s desiderata for mathematical notations are presented as ten guidelines pertinent to notational design and its application to both individual symbols and complex expressions. To illustrate the applicability of these guidelines in non-mathematical domains, some aspects of his Mechanical Notation are also discussed. 相似文献
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Dirk Ahrens Wangang Liu Silvia Fabrizi Ming Bai Xing-Ke Yang 《Journal of Natural History》2015,49(17-18):1073-1130
This paper revises the species belonging to the Neoserica (sensu lato) vulpes group and results in one new combination, Neoserica (sensu lato) vulpes (Arrow, 1946) comb. nov., and 24 new species originating mainly from south-western China: N. baishuiensis sp. nov., N. baoshana sp. nov., N. biuncinata sp. nov., N. dundai sp. nov., N. ganhaiziana sp. nov., N. heishuiana sp. nov., N. kereni sp. nov., N. laocaiana sp. nov., N. lateriuncinata sp. nov., N. leiboensis sp. nov., N. luzhouana sp. nov., N. ningyuanensis sp. nov., N. nykli sp. nov., N. parausta sp. nov., N. pseudovulpes sp. nov., N. rubellula sp. nov., N. ruzickai sp. nov., N. shinkaisiensis sp. nov., N. sichuanica sp. nov., N. usta sp. nov., N. weishanensis sp. nov., N. xiaguanensis sp. nov., N. kunmingensis sp. nov. and N. yangjiapingensis sp. nov. A key to species and illustrations of genitalia and habitus of adults are given, including distribution maps of all species.http://zoobank.org/urn:lsid:zoobank.org:pub:3FE6CC54-DB3A-4201-A6F9-332E4A397268 相似文献
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Tissue microfibrils contain fibrillin-1 as a major constituent. Microfibrils regulate bioavailability of TGFβ superfamily
growth factors and are structurally crucial in the ocular zonule. FBN1 mutations typically cause the Marfan syndrome, an autosomal dominant disorder manifesting with skeletal overgrowth, aortic
aneurysm, and lens dislocation (ectopia lentis). Infrequently, FBN1 mutations cause dominantly inherited Weill–Marchesani syndrome (WMS), isolated ectopia lentis (IEL), or the fibrotic condition, geleophysic dysplasia (GD). Intriguingly, mutations in ADAMTS [a disintegrin-like and metalloprotease
(reprolysin-type) with thrombospondin type 1 motif] family members phenocopy these disorders, leading to recessive WMS (ADAMTS10), WMS-like syndrome (ADAMTS17), IEL (ADAMTSL4 and ADAMTS17) and GD (ADAMTSL2). An ADAMTSL2 founder mutation causes Musladin–Lueke syndrome, a fibrotic disorder in beagle dogs. The overlapping disease spectra resulting
from fibrillin-1 and ADAMTS mutations, interaction of ADAMTS10 and ADAMTSL2 with fibrillin-1, and evidence that these ADAMTS
proteins accelerate microfibril biogenesis, constitutes a consilience suggesting that some ADAMTS proteins evolved to provide
a novel mechanism regulating microfibril formation and consequently cell behavior. 相似文献
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Borgel J Guibert S Li Y Chiba H Schübeler D Sasaki H Forné T Weber M 《Nature genetics》2010,42(12):1093-1100
DNA methylation is extensively reprogrammed during the early phases of mammalian development, yet genomic targets of this process are largely unknown. We optimized methylated DNA immunoprecipitation for low numbers of cells and profiled DNA methylation during early development of the mouse embryonic lineage in vivo. We observed a major epigenetic switch during implantation at the transition from the blastocyst to the postimplantation epiblast. During this period, DNA methylation is primarily targeted to repress the germline expression program. DNA methylation in the epiblast is also targeted to promoters of lineage-specific genes such as hematopoietic genes, which are subsequently demethylated during terminal differentiation. De novo methylation during early embryogenesis is catalyzed by Dnmt3b, and absence of DNA methylation leads to ectopic gene activation in the embryo. Finally, we identify nonimprinted genes that inherit promoter DNA methylation from parental gametes, suggesting that escape of post-fertilization DNA methylation reprogramming is prevalent in the mouse genome. 相似文献
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Aulchenko YS Hoppenbrouwers IA Ramagopalan SV Broer L Jafari N Hillert J Link J Lundström W Greiner E Dessa Sadovnick A Goossens D Van Broeckhoven C Del-Favero J Ebers GC Oostra BA van Duijn CM Hintzen RQ 《Nature genetics》2008,40(12):1402-1403
The few loci associated with multiple sclerosis (MS) are all related to immune function. We report a GWA study identifying a new locus replicated in 2,679 cases and 3,125 controls. An rs10492972[C] variant located in the KIF1B gene was associated with MS with an odds ratio of 1.35 (P = 2.5 x 10(-10)). KIF1B is a neuronally expressed gene plausibly implicated in the irreversible axonal loss characterizing MS in the long term. 相似文献
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David P. Livingston III Dirk K. Hincha Arnd G. Heyer 《Cellular and molecular life sciences : CMLS》2009,66(13):2007-2023
Numerous studies have been published that attempted to correlate fructan concentrations with freezing and drought tolerance.
Studies investigating the effect of fructan on liposomes indicated that a direct interaction between membranes and fructan
was possible. This new area of research began to move fructan and its association with stress beyond mere correlation by confirming
that fructan has the capacity to stabilize membranes during drying by inserting at least part of the polysaccharide into the
lipid headgroup region of the membrane. This helps prevent leakage when water is removed from the system either during freezing
or drought. When plants were transformed with the ability to synthesize fructan, a concomitant increase in drought and/or
freezing tolerance was confirmed. These experiments indicate that besides an indirect effect of supplying tissues with hexose
sugars, fructan has a direct protective effect that can be demonstrated by both model systems and genetic transformation. 相似文献
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Herring CD Raghunathan A Honisch C Patel T Applebee MK Joyce AR Albert TJ Blattner FR van den Boom D Cantor CR Palsson BØ 《Nature genetics》2006,38(12):1406-1412
We applied whole-genome resequencing of Escherichia coli to monitor the acquisition and fixation of mutations that conveyed a selective growth advantage during adaptation to a glycerol-based growth medium. We identified 13 different de novo mutations in five different E. coli strains and monitored their fixation over a 44-d period of adaptation. We obtained proof that the observed spontaneous mutations were responsible for improved fitness by creating single, double and triple site-directed mutants that had growth rates matching those of the evolved strains. The success of this new genome-scale approach indicates that real-time evolution studies will now be practical in a wide variety of contexts. 相似文献
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