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排序方式: 共有143条查询结果,搜索用时 31 毫秒
31.
Journal of Systems Science and Complexity - The Global Entrepreneurship and Development Institute annually publishes the Global Entrepreneurship Index (GEI) to show entrepreneurship of each... 相似文献
32.
Terry Barker 《Journal of forecasting》1985,4(2):133-151
This paper compares the forecasts of recession and recovery made by five non-government U.K. teams modelling the economy (Cambridge Econometrics, the London Business School, the National Institute of Economic and Social Research, the Cambridge Economic Policy Group and the Liverpool Research Group). The paper concentrates on annual ex ante projections as published over the period 1978-1982, i.e. forecasts made, before the event, of the onset, length, depth and character of the economic recession in the U.K. which began in 1979. The comparison is in terms of year by year changes in production, unemployment, prices and other variables. It concludes that no group was systematically better or worse than other groups (confirming U.S. experience) and that the groups tended to perform better in their chosen areas of specialization, e.g. medium-term groups did better at forecasting the medium-term outcome. 相似文献
33.
34.
Issues of social responsibility, ethics and interdependence, as well as the pragmatic imperative to better understand complexity,
require that diverse viewpoints be invited and given credence by policy makers seeking imaginative ‘solutions’ to climate
change. This paper explores the statutory introduction of biofuels into New Zealand by way of the discourses that preceded
this decision. This inquiry used Critically Systemic Thinking and ‘Mode 2’ Soft Systems Methodology (SSM) to engage with multiple
stakeholders to the Biofuels policy to discover how the discourse was conducted. It concludes that the process of policymaking
was framed in technical rationalist terms thereby favouring certain ‘worldviews’ over others. Accordingly, a model of ‘ideal’
discourse and decision making for governing the conduct of future public discourse is presented. This inquiry assists in re-establishing
SSM as a rigorous and reflexive approach to analysing a complex issue and for enhancing collective learning into its content
and process. 相似文献
35.
Daffonchio D Borin S Brusa T Brusetti L van der Wielen PW Bolhuis H Yakimov MM D'Auria G Giuliano L Marty D Tamburini C McGenity TJ Hallsworth JE Sass AM Timmis KN Tselepides A de Lange GJ Hübner A Thomson J Varnavas SP Gasparoni F Gerber HW Malinverno E Corselli C Garcin J McKew B Golyshin PN Lampadariou N Polymenakou P Calore D Cenedese S Zanon F Hoog S;Biodeep Scientific Party 《Nature》2006,440(7081):203-207
The chemical composition of the Bannock basin has been studied in some detail. We recently showed that unusual microbial populations, including a new division of Archaea (MSBL1), inhabit the NaCl-rich hypersaline brine. High salinities tend to reduce biodiversity, but when brines come into contact with fresher water the natural haloclines formed frequently contain gradients of other chemicals, including permutations of electron donors and acceptors, that may enhance microbial diversity, activity and biogeochemical cycling. Here we report a 2.5-m-thick chemocline with a steep NaCl gradient at 3.3 km within the water column betweeen Bannock anoxic hypersaline brine and overlying sea water. The chemocline supports some of the most biomass-rich and active microbial communities in the deep sea, dominated by Bacteria rather than Archaea, and including four major new divisions of Bacteria. Significantly higher metabolic activities were measured in the chemocline than in the overlying sea water and underlying brine; functional analyses indicate that a range of biological processes is likely to occur in the chemocline. Many prokaryotic taxa, including the phylogenetically new groups, were confined to defined salinities, and collectively formed a diverse, sharply stratified, deep-sea ecosystem with sufficient biomass to potentially contribute to organic geological deposits. 相似文献
36.
An RNA map predicting Nova-dependent splicing regulation 总被引:1,自引:0,他引:1
Ule J Stefani G Mele A Ruggiu M Wang X Taneri B Gaasterland T Blencowe BJ Darnell RB 《Nature》2006,444(7119):580-586
37.
A general approach to single-nucleotide polymorphism discovery 总被引:29,自引:0,他引:29
Marth GT Korf I Yandell MD Yeh RT Gu Z Zakeri H Stitziel NO Hillier L Kwok PY Gish WR 《Nature genetics》1999,23(4):452-456
Single-nucleotide polymorphisms (SNPs) are the most abundant form of human genetic variation and a resource for mapping complex genetic traits. The large volume of data produced by high-throughput sequencing projects is a rich and largely untapped source of SNPs (refs 2, 3, 4, 5). We present here a unified approach to the discovery of variations in genetic sequence data of arbitrary DNA sources. We propose to use the rapidly emerging genomic sequence as a template on which to layer often unmapped, fragmentary sequence data and to use base quality values to discern true allelic variations from sequencing errors. By taking advantage of the genomic sequence we are able to use simpler yet more accurate methods for sequence organization: fragment clustering, paralogue identification and multiple alignment. We analyse these sequences with a novel, Bayesian inference engine, POLYBAYES, to calculate the probability that a given site is polymorphic. Rigorous treatment of base quality permits completely automated evaluation of the full length of all sequences, without limitations on alignment depth. We demonstrate this approach by accurate SNP predictions in human ESTs aligned to finished and working-draft quality genomic sequences, a data set representative of the typical challenges of sequence-based SNP discovery. 相似文献
38.
Infantile-onset symptomatic epilepsy syndrome caused by a homozygous loss-of-function mutation of GM3 synthase 总被引:8,自引:0,他引:8
Simpson MA Cross H Proukakis C Priestman DA Neville DC Reinkensmeier G Wang H Wiznitzer M Gurtz K Verganelaki A Pryde A Patton MA Dwek RA Butters TD Platt FM Crosby AH 《Nature genetics》2004,36(11):1225-1229
We identified an autosomal recessive infantile-onset symptomatic epilepsy syndrome associated with developmental stagnation and blindness. Assuming a founder effect in a large Old Order Amish pedigree, we carried out a genome-wide screen for linkage and identified a single region of homozygosity on chromosome 2p12-p11.2 spanning 5.1 cM (maximum lod score of 6.84). We sequenced genes in the region and identified a nonsense mutation in SIAT9, which is predicted to result in the premature termination of the GM3 synthase enzyme (also called lactosylceramide alpha-2,3 sialyltransferase). GM3 synthase is a member of the sialyltransferase family and catalyzes the initial step in the biosynthesis of most complex gangliosides from lactosylceramide. Biochemical analysis of plasma glycosphingolipids confirmed that affected individuals lack GM3 synthase activity, as marked by a complete lack of GM3 ganglioside and its biosynthetic derivatives and an increase in lactosylceramide and its alternative derivatives. Although the relationship between defects in ganglioside catabolism and a range of lysosomal storage diseases is well documented, this is the first report, to our knowledge, of a disruption of ganglioside biosynthesis associated with human disease. 相似文献
39.
The owl can discriminate changes in the location of sound sources as small as 3 degrees and can aim its head to within 2 degrees of a source. A typical neuron in its midbrain space map has a spatial receptive field that spans 40 degrees--a width that is many times the behavioural threshold. Here we have quantitatively examined the relationship between neuronal activity and perceptual acuity in the auditory space map in the barn owl midbrain. By analysing changes in firing rate resulting from small changes of stimulus azimuth, we show that most neurons can reliably signal changes in source location that are smaller than the behavioural threshold. Each source is represented in the space map by a focus of activity in a population of neurons. Displacement of the source causes the pattern of activity in this population to change. We show that this change predicts the owl's ability to detect a change in source location. 相似文献
40.
提出了一种能够提高ITU-TG.729算法性能的静音检测技术,该技术的引入不仅可以降低G.729的语音通讯平均传输出特率,而且可以大量节省G.729压缩和解压过程的实际运算量,通过在不同的噪声背景下的性能分析,该静音检测技术的引入不会对G.729算法的合成语音质量产生明显的影响。 相似文献