Dynamic Dominating Set and Turbo-Charging Greedy Heuristics

The main purpose of this paper is to exposit two very different, but very general, motivational schemes in the art of parameterization and a concrete example connecting them. We introduce a dynamic version of the DOMINATING SET problem and prove that it is fixed-parameter tractable（FPT）. The problem is motivated by settings where problem instances evolve. It also arises in the quest to improve a natural greedy heuristic for the DOMINATING SET problem.     

Flora of the Lee Creek valley, Alberta

The floristic composition of the Lee Creek valley in southwestern Alberta, Canada, is presented. The valley flora consists of 299 species of vascular plants representing 173 genera and 46 families. The flora is dominated by forbs (73 percent), followed by grasses (24 percent), shrubs (12 percent), and trees (11 percent). The valley of Lee Creek is divided into upper and lower sections on the basis of elevational, climatic, and biotic differences. Floristic richness of the Lee Creek valley is quite evenly divided between the upper and lower valleys: 105 species limited to the upper valley, 95 to the lower valley, and 99 species shared by both upper and lower valleys.     

2004-based national population projections for the UK and constituent countries

The 2004-based national population projections, carried out by the Government Actuary in consultation with the Registrars General, show the population of the United Kingdom (UK) rising from 59.8 million in 2004, passing 60 million in 2005 and 65 million in 2023, to reach 67.0 million by 2031. In the longer-term, the projections suggest that the population will continue rising beyond 2031 but at a much lower rate of growth. The population will become older with the median age expected to rise from 38.6 years in 2004 to 42.9 years by 2031. With the current plans for a common state pension age of 65 for both sexes from 2020, the number of people of working age for every person of state pensionable age is projected to fall from 3.33 in 2004 to 2.62 by 2031.     

太极拳干预社区中老年人亚健康状态的临床随机对照试验

目的:评价太极拳干预中老年亚健康的疗效。方法:采用随机单盲方法,将符合亚健康诊断标准的受试者100例,随机分为太极拳干预组和一般运动干预组。两组受试者分别进行每周三次,每次30min的太极拳锻炼和一般体育运动锻炼,疗程均为16周。临床疗效观察采用SF-36生命质量评分。结果:太极拳干预组生命质量干预前后评分差值与一般体育运动组比较显示:在总体健康和生命活力两个维度的差异有统计学意义。结论:太极拳较一般运动能更好地改善中老年亚健康人群生命质量。     

Human infection by genetically diverse SIVSM-related HIV-2 in west Africa.

Our understanding of the biology and origins of human immunodeficiency virus type 2 (HIV-2) derives from studies of cultured isolates from urban populations experiencing epidemic infection and disease. To test the hypothesis that such isolates might represent only a subset of a larger, genetically more diverse group of viruses, we used nested polymerase chain reactions to characterize HIV-2 sequences in uncultured mononuclear blood cells of two healthy Liberian agricultural workers, from whom virus isolation was repeatedly unsuccessful, and from a culture-positive symptomatic urban dweller. Analysis of pol, env and long terminal repeat regions revealed the presence of three highly divergent HIV-2 strains, one of which (from one of the healthy subjects) was significantly more closely related to simian immunodeficiency viruses infecting sooty mangabeys and rhesus macaques (SIVSM/SIVMAC) than to any virus of human derivation. This subject also harboured multiply defective viral genotypes that resulted from hypermutation of G to A bases. Our results indicate that HIV-2, SIVSM and SIVMAC comprise a single, highly diverse group of lentiviruses which cannot be separated into distinct phylogenetic lineages according to species of origin.     

SB-restricted presentation of influenza and herpes simplex virus antigens to human T-lymphocyte clones

The HLA-D region of the human major histocompatibility complex (MHC) has been shown to be homologous to the murine I region in terms of both structure and function. Both regions encode class II MHC molecules which restrict T-lymphocyte interactions with antigen-presenting cells. We have recently described the MHC restriction and antigen specificities of human T-lymphocyte clones directed at strain A influenza virus. The majority of T-lymphocyte clones recognized antigen in the context of cell surface interaction products encoded by HLA-D/DR genes. However, a few clones recognized antigen presented by cells histoincompatible for D/DR antigens. We report here that some of these clones recognized viral antigens in association with antigens encoded by genes identical with or closely linked to the recently described secondary B-cell (SB) locus of the MHC. This is the first report that SB-restricted antigen recognition may form an integral part of normal, human immune responses.