浅谈如何做好运输收入的计划工作

运输收入计划是运输收入管理的基本环节，计划工作的好坏直接影响着铁路运输业的经济效益。文章从计划工作的环节、做好计划工作应注意的几个问题方面。说明了如何做好运输收入的计划工作。     

Genome sequence and comparative analysis of the model rodent malaria parasite Plasmodium yoelii yoelii

Species of malaria parasite that infect rodents have long been used as models for malaria disease research. Here we report the whole-genome shotgun sequence of one species, Plasmodium yoelii yoelii, and comparative studies with the genome of the human malaria parasite Plasmodium falciparum clone 3D7. A synteny map of 2,212 P. y. yoelii contiguous DNA sequences (contigs) aligned to 14 P. falciparum chromosomes reveals marked conservation of gene synteny within the body of each chromosome. Of about 5,300 P. falciparum genes, more than 3,300 P. y. yoelii orthologues of predominantly metabolic function were identified. Over 800 copies of a variant antigen gene located in subtelomeric regions were found. This is the first genome sequence of a model eukaryotic parasite, and it provides insight into the use of such systems in the modelling of Plasmodium biology and disease.     

Evidence for non-selective preservation of organic matter in sinking marine particles

The sinking of particulate organic matter from ocean surface waters transports carbon to the ocean interior, where almost all is then recycled. The unrecycled fraction of this organic matter can become buried in ocean sediments, thus sequestering carbon and so influencing atmospheric carbon dioxide concentrations. The processes controlling the extensive biodegradation of sinking particles remain unclear, partly because of the difficulty in resolving the composition of the residual organic matter at depth with existing chromatographic techniques. Here, using solid-state 13C NMR spectroscopy, we characterize the chemical structure of organic carbon in both surface plankton and sinking particulate matter from the Pacific Ocean and the Arabian Sea. We found that minimal changes occur in bulk organic composition, despite extensive (>98%) biodegradation, and that amino-acid-like material predominates throughout the water column in both regions. The compositional similarity between phytoplankton biomass and the small remnant of organic matter reaching the ocean interior indicates that the formation of unusual biochemicals, either by chemical recombination or microbial biosynthesis, is not the main process controlling the preservation of particulate organic carbon within the water column at these two sites. We suggest instead that organic matter might be protected from degradation by the inorganic matrix of sinking particles.     

A candidate prostate cancer susceptibility gene at chromosome 17p

It is difficult to identify genes that predispose to prostate cancer due to late age at diagnosis, presence of phenocopies within high-risk pedigrees and genetic complexity. A genome-wide scan of large, high-risk pedigrees from Utah has provided evidence for linkage to a locus on chromosome 17p. We carried out positional cloning and mutation screening within the refined interval, identifying a gene, ELAC2, harboring mutations (including a frameshift and a nonconservative missense change) that segregate with prostate cancer in two pedigrees. In addition, two common missense variants in the gene are associated with the occurrence of prostate cancer. ELAC2 is a member of an uncharacterized gene family predicted to encode a metal-dependent hydrolase domain that is conserved among eukaryotes, archaebacteria and eubacteria. The gene product bears amino acid sequence similarity to two better understood protein families, namely the PSO2 (SNM1) DNA interstrand crosslink repair proteins and the 73-kD subunit of mRNA 3' end cleavage and polyadenylation specificity factor (CPSF73).     

Direct detection of a microlens in the Milky Way.

The nature of dark matter remains mysterious, with luminous material accounting for at most approximately 25 per cent of the baryons in the Universe. We accordingly undertook a survey looking for the microlensing of stars in the Large Magellanic Cloud (LMC) to determine the fraction of Galactic dark matter contained in massive compact halo objects (MACHOs). The presence of the dark matter would be revealed by gravitational lensing of the light from an LMC star as the foreground dark matter moves across the line of sight. The duration of the lensing event is the key observable parameter, but gives non-unique solutions when attempting to estimate the mass, distance and transverse velocity of the lens. The survey results to date indicate that between 8 and 50 per cent of the baryonic mass of the Galactic halo is in the form of MACHOs (ref. 3), but removing the degeneracy by identifying a lensing object would tighten the constraints on the mass in MACHOs. Here we report a direct image of a microlens, revealing it to be a nearby low-mass star in the disk of the Milky Way. This is consistent with the expected frequency of nearby stars acting as lenses, and demonstrates a direct determination of a lens mass from a microlensing event. Complete solutions such as this for halo microlensing events will probe directly the nature of the MACHOs.     

混合型粗集料轻混凝土的微观结构（Ⅱ）

在混合型粗集料轻混凝土的微观结构（I）对早期水化产物和结构特点进行全面分析和论证的基础上,进一步对后期的水化产物和结构特点进行了系统的研究和论述。同时,对陶粒－水泥石界面与碎石－水泥石界面的微观结构进行了分析和类比。并提出,在两种不同的界面处,分别 存在着不同的水化条件和水化产物,因而显示出不同的微观结构形态。     

混合型粗集料轻混凝土的微观结构（I）

在轻集料混凝土内,微观结构的改变,对混凝土性能的影响,目前还没有人作过系统的研究,也就是说,对于轻集料混凝土,其微观结构的具体类型、微观结构与各项理化性能之间的关系,基本上还是个空白,针对以上的具体事实,研究中采用X光（XRD）、电镜（SEM）、红外（IR）和差热（DTA）等探测手段,对所配高性能轻集料混凝土微观结构的具体类型及转化,微观结构与各项理化性能之间的关系,进行了全面的研究和测定,并着重提出：①由于陶粒的微泵作用,陶粒颗粒的内部会形成内部水化产物,除其它影响因素之外,陶粒内部水化产物的形成,将有效地提高陶粒本身和陶粒混凝土的强度。②由于界面反应,在陶粒与水泥石界面处会形成与水泥石基体相微观结构不同的9A^。托勃莫来石矿物。最后对其相应的早期水化产物及其结构特点,进行发分析和论证。