昨天讲的那个故事，是 Gelfand 在为纪念他老人家 90 大寿的一个国际会议上的开场白，那个会议的主题是“ The Unity of Mathematics ”，时间是 2003 年 9 月 4 日 ，地点在麻省的剑桥。 G 老还说，美丽简单和精确，外加疯狂的思想，是数学与音乐共有的奇妙组合，而当人们想起音乐时，并不像数学那样将它分成不同的领域。作曲家会说，“我是作曲家”，但不会说“我是四重奏作曲家。”因为这一点，当有人问 G 老是什么专业的数学家时，他总是回答，“ I am a mathematician ”。 其实，音乐似乎也分了科的， G 老要那么说，是因为他几乎是 20 世纪最后一个在数学中通吃的大家。 2009 年 10 月 6 日 ， G 老驾鹤西去时，人们忽然发现 Gelfand 在意地绪语（ G 是犹太人）里是大象的意思，而他真的就是一头数学的大象。多数数学家都抱着大象的一条腿或者尾巴， G 老总是能看见整个大象。 Singer 说 G 老是巨人，像舞蹈里的 Balanchine ，文学里的 Thomas Mann ，音乐里的 Stravinsky 甚至 Mozart ，更像画家的 Cezanne 和 Matisse 。大诗人 Paul Rilke 评 Cezanne 说， C 是他的超级偶像（ my supreme example ），因为四十年来他令他看到了画外的东西（ he has remained in the innermost center of his workfor forty years…which explains something beyond the freshness and purity of hispaintings ）—— S 说，他对 G 老的崇拜也是一样，而且时间更长。 更能说明那头大象的是， S 问过一些人，你对 G 老的什么东西感兴趣。结果很有意思，各人提出的题目都不一样，几乎没有重复交叉的。 S 列举了一个小清单： 1. Normed rings 2. C*-Algebras(with Raikov)—the GNS Construction 3. Representationsof complex and real semisimple groups (with Naimark and Graev) 4. IntegralGeometry—Generalizations of the Radon Transform 5. Inverse scatteringof Sturm-Liouville systems (with Levitan) 6. Gelfand-Dickeyon Lax operators and KdV 7. The treatiseson generalized functions 8. Ellipticequations 9. The cohomologyof infinite dimensional Lie algebras (with Fuchs) 10. Combinatorialcharacteristic classes (beginning with MacPherson) 11. Dilogarithms,discriminants, hypergeometric functions 12. The Gelfandseminar
Dai X, Duffy K. 2008. Monthly activity centers of African elephants in a small game reserve. Multifunctional grasslands in a changing world I (XXI International grassland congress and VII International rangland congress).Guangdong People’s Publishing House. 2008, Vol.1: 492. 2008世界草地与草原大会论文：一个小型野生动物保护区中非洲象的每月活动中心点 ----------------------------------------------------------------------------------------------------------------------------------------------------- Monthly activity centres of african elephants in a small game reserve Xiaohua Dai 1,2 And Kevin Duffy 1 1 Centre for Systems Research, Durban University of Technology, Durban 4000, South Africa. E-mail: kevind@dut.ac.za 2 School of Chemistry and Life Science, GanNan Normal University, Ganzhou 341000, Jiangxi Province, China. E-mail: ecoinformatics(at)gmail.com Keywords : African elephants, centre of activity, home range, harmonic mean, marula Introduction Due to habitat heterogeneity and environmental variation, the home range and habitat utilization of African elephants varies in different years and different seasons, not only in large protected areas but also in small reserves (Shannon et al., 2006). Although there are many studies on seasonal changes of elephant home ranges, no articles on finer temporal shifts within elephant home ranges are published. Monthly movement rhythms should provide more detail on elephant foraging and its impacts and help the conservation and management of both elephants and their habitats, especially in small reserves. Materials and Methods Radio and satellite collars on the elephants were fitted by a veterinary surgeon in a humane manner, and in accordance with laws governing animal anticruelty in South Africa. All elephant locations were projected into UTM 1983 (Zone 36) datum. Since the datasets are sampled differently, the analyses include only the first daily location and separated by sex. Using these data monthly harmonic mean centres of elephants were determined using ArcView Animal Movement Analyst Extension (the number of divisions of the X axis: 100). Results For both bulls and cows the elephants are more active in the northern PGR, with oscillations to other regions in other months. These monthly regional preferences are generally consistent across years and a generalised cadence pattern is given in Fig. 1. For bulls the monthly cadence in activity is primarily between the northern PGR and the high marula densities area. The cow herd activity oscillates between the northern region and the southern PGR. These patterns of activity are partly disrupted in the dry months i.e. activity centres are more widely distributed. In February both bulls and cows are found in the central part of the PGR which appear to relate to the marula distribution area (Fig. 1). For the months adjoining months January and March they are in the north. From late April or May, elephant activity centres shifted from the north. From September or October when the first spring rains fell elephant activity centres shifted back to the north (Fig. 1). Bull and cow activity centres were only close together in the wet season from November to February (Fig. 1). Conclusions Our results show that elephant activity over that period had similar month-by-month rhythms in different years, which appeared to be related to rainfall, vegetation, distribution of cow herd, marula ( Sclerocarya birrea ) fruiting and hunting. Food appears to play an influencing role in the elephant movements. Monthly activity centres of both bulls and cows were more widely distributed in the dry months than in the wet months. Bulls keep relatively close to the herd only in very wet months. There is a close association between fruiting of marula and the distribution of elephants in February. Rainfall appears to have an indirect but influencing impact on elephant ranging behaviour. Knowledge of elephant monthly movements is not only helpful for the design of suitable management strategies but could be used for the estimation of minimum size for a small reserve. References Shannon, G., Page, B.R., Duffy, K., Slotow,R. 2006. African elephant home range and habitat selection in Pongola Game Reserve, South Africa. Afr. Zool. 41: 37–44. Full Text 全文
Dai, X. H., G. Shannon, et al. (2007). Short-duration daytime movements of a cow herd of African elephants. Journal of Mammalogy 88(1): 151-157. We examined daytime movements of a herd of African elephants (Loxodonta africana) at 10-min, 15-min, and 20- min intervals in Pongola Game Reserve, South Africa. This group tended to proceed in a consistent direction during consecutive movements, especially during long moves. Serial movement lengths and serial movement angles were autocorrelated at 10-min and 15-min intervals but not at 20-min intervals, indicating that 20-min intervals may be a suitable temporal scale to avoid oversampling. Herd movements followed a Leacute;vy-modulated correlated random walk. In addition, looping movements were detected. Spatial scale of the loops averaged about 1 km. Movement strategies that include both Leacute;vy walks and correlated random walks are thought to optimize foraging. Key words: animal movement, elephant, Leacute;vy walk, looping, Loxodonta africana 我的论文摘要： http://www.getcited.org/?MBR=11061629 文章下载(fulltext pdf)
标签: 大象
