A forecasting comparison of classical and Bayesian methods for modelling logistic diffusion

A Bayesian procedure for forecasting S‐shaped growth is introduced and compared to classical methods of estimation and prediction using three variants of the logistic functional form and annual times series of the diffusion of music compact discs in twelve countries. The Bayesian procedure was found not only to improve forecast accuracy, using the medians of the predictive densities as point forecasts, but also to produce intervals with a width and asymmetry more in accord with the outcomes than intervals from the classical alternative. While the analysis in this paper focuses on logistic growth, the problem is set up so that the methods are transportable to other characterizations of the growth process. Copyright © 2001 John Wiley & Sons, Ltd.     

Hotspots of aberrant epigenomic reprogramming in human induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) offer immense potential for regenerative medicine and studies of disease and development. Somatic cell reprogramming involves epigenomic reconfiguration, conferring iPSCs with characteristics similar to embryonic stem (ES) cells. However, it remains unknown how complete the reestablishment of ES-cell-like DNA methylation patterns is throughout the genome. Here we report the first whole-genome profiles of DNA methylation at single-base resolution in five human iPSC lines, along with methylomes of ES cells, somatic cells, and differentiated iPSCs and ES cells. iPSCs show significant reprogramming variability, including somatic memory and aberrant reprogramming of DNA methylation. iPSCs share megabase-scale differentially methylated regions proximal to centromeres and telomeres that display incomplete reprogramming of non-CG methylation, and differences in CG methylation and histone modifications. Lastly, differentiation of iPSCs into trophoblast cells revealed that errors in reprogramming CG methylation are transmitted at a high frequency, providing an iPSC reprogramming signature that is maintained after differentiation.     

不同文化对企业创新决策的影响研究

运用社会认知、信息处理和专家知识理论,建立了一个可操作的多文化企业创新模型,探讨了不同文化对企业创新决策的影响.详述了组织、意愿和能力认知特质对企业创新决策的影响以及文化价值观对认知特质和企业创新决策的影响.通过对太平洋地区7个国家677个被访者的调研以及分析调研数据,验证了研究结果.     

Quality vs. quantity of publications in nanotechnology field from the People’s Republic of China

This study evaluates trends in quality of nanotechnology and nanoscience papers produced by authors from the People＇s Republic of China （PRC）. The metric used to gauge quality is ratio of highly cited nanotechnology papers to total nanotechnology papers produced in sequential time frames. The USA is both the most prolific nanotechnology publishing country and most represented country on highly cited nanotechnology papers （both in absolute numbers of highly cited papers and highly cited papers relative to total publications） over the 1998-2003 time frame, based on the SCl/SSCl databases. Some of the smaller hi-tech countries have relatively high ratios （-2） of highly cited papers to total publications （e.g. Denmark, Netherlands, Switzerland）. Countries that have exhibited rapid growth in SCl/SSCl nanotechnology paper production in recent years （e.g. PRC, South Korea） had ratios an order of magnitude less than that of the USA for 1998, but by 2003 had increased to about 20% that of the USA （-2.5）. PRC and South Korea have climbed in the publications rankings from 6th and 9th in 1998, respectively, to 2nd and 6th in 2005, respectively. PRC＇s ratio monotonically increased from 0.16 to 0.45 over the 1998-2003 period, and South Korea＇s ratio increased from 0.11 to about 0.6 over that same period, indicating their papers are getting more and more citations proportionately. Thus, under rapid growth conditions, PRC and South Korea have been able to increase their share of participation in highly cited papers. As of 2003, PRC and South Korea have ratios comparable to nations like Japan, France, Italy, and Australia but not yet approaching those of the highly cited countries. None of the top ten publications producing institutions are from the USA, while all of the top ten highly cited publications producers are from the USA. Over the 1998-2003 time period, the top six total publications producing institutions （globally） remained the same, with Chinese Academy of Sciences （which consists     

Feyerabend's perspectivism

Although, Feyerabend himself seems never to have used the term ‘perspectivism’ to designate a philosophical position, I think his views about science are very well characterized as perspectival. In fact, his later writings contain much that contributes to current thinking about perspectivism. I would like, therefore, to distinguish my own perspectivism from Feyerabend's. In the end, I will argue, his perspectivism is lacking enough of the critical bite that the younger Feyerabend found so attractive in Popper's philosophy.     

Scientific perspectivism: behind the stage door

Adopting the stage metaphor suggested in Brown’s review, and treating Scientific perspectivism as a play in five acts, I respond to his review as a playwright might respond to a generally favorable review. Taking the reader behind the stage door, I discuss the playwright’s intentions for each act, paying special attention to the expected audience for the play as a whole. The result, therefore, supplements the review from the standpoint of the playwright. It also provides answers to some of the reviewer’s questions.     

A checklist of the vascular plants of the House Range, Utah

A checklist of the vascular plants of the House Range, Juab and Millard counties, Utah, is presented. A flora of 373 species and infraspecific taxa in 231 genera and 60 families are reported. The geology, physiography, climate, and plant communities are briefly discussed. Several endemics occur in the study area and a new taxon has been described.     

Microhabitat affinities of Gambel oak seedlings

Previous work suggested that Gambel oak seedlings are rare in the northern parts of its range in Utah where summer rainfall is relatively low but should be abundant in southern parts of the range where summer rainfall is usually high. Gambel oak grades from a relatively minor component of a ponderosa pine/mixed conifer assemblage in the south to a virtually monotypic formation in the north, where it exists as long-lived clones.   Quadrat analysis in Arizona and New Mexico, within the oak zone, revealed a seedling density ranging from 120 to 1320 per hectare. We found a significant tendency of seedlings to be located on the NE (cool, shady) side of sheltering objects in the environment. Mature ponderosa pine ranged in density from ca 40 to 500 stems per hectare, whereas mature Gambel oak ranged from ca 10 to 20 genets per hectare with ca 1 to 7 ramets per clone. These results support our previous conclusion that Gambel oak in northern Utah probably became established as a minor component of a mixed pine/oak woodland at a time in mid-Holocene when summer rainfall was much higher than today.     

Effectiveness of the seed wing of Pinus flexilis in wind dispersal

Limber pine ( Pinus flexilis James) seeds are usually wingless but occasionally have short, stubby wings. To determine the effectiveness of these wings in slowing seed descent, rates of fall were determined before and after wing removal. A similar experiment was conducted with seeds of Himalayan blue pine ( P. griffithii McClelland), a white pine with typically long seed wings. The short wings of limber pine seeds were found to influence rate of seed fall far less than the wings of Himalayan blue pine. This is consistent with evidence suggesting that limber pine seeds are not effectively dispersed by wind but are dependent for dispersal on Clark's Nutcracker ( Nucifraga columbiana ).