Autoradiographic study of the penetration of non-histone chromatin proteins into differentiating cells.

Attention has previously been drawn to a specific effect of NHCP on embryonic Pleurodeles cell differentiation. With a modified NHCP labelling technique, autoradiography has revealed a cytoplasmic concentration of labelled NHCP and has not revealed any difference between homospecific and heterospecific NHCP penetration.     

Spontaneous robertsonian fusion leading to karyotype variation in the house mouse — First report from Asia

Summary The occurrence of spontaneous Robertsonian fusion leading to 2n=39 chromosomes (NF=40) in the house mouse (Mus musculus domesticus) has been reported for the first time from Asia. 3 phenotypically normal female mice collected from 2 distantly located populations of India (Tripura and Calcutta) show centric fusion in somatic chromosomes between pairs 2 and 16, and 8 and 14 respectively. C-banding analysis revealed that the (sub) metacentric has been originated by fusion between the broken/eroded centromeres of 2 telocentric chromosomes.     

益阳地区遥感土地利用分类的波段组合效应分析

波段组合对监督分类的运算效率和分类结果有着显著影响。本文以湖南益阳TM影像为实验数据,通过波段光谱特征统计分析、叠合光谱图分析,对该地区土地利用分类波段进行了初步选取;按照3波段组合方式进行分类,并对分类效应进行了比较分析。结果表明,耕地和草地难区分、未利用土地易错分为建设用地是共同问题;TM2、3、4组合能够较好地区分耕地和草地,同时对林地和草地的区分效果也最好,分类总精度最高;TM2、3、5组合对未利用土地的识别能力相对最高;TM2、3、7组合,TM2、4、7组合以及TM2、5、7组合对水体的分类效果最好。本研究对数据降维、资料不足时最大限度发挥资料可用性、针对特别应用目的进行传感器波段设计具有一定的参考价值。     

The hematopoietic stem-cell niche in health and leukemia

Research in the last decade has shown that hematopoietic stem cells (HSCs) interact with and are modulated by a complex multicellular microenvironment in the bone marrow, which includes both the HSC progeny and multiple non-hematopoietic cell types. Intense work is gradually throwing light on the composition of the HSC niche and the molecular cues exchanged between its components, which has implications for HSC production, maintenance and expansion. In addition, it has become apparent that bidirectional interactions between leukemic cells and their niche play a previously unrecognized role in the initiation and development of hematological malignancies. Consequently, targeting of the malignant niche holds considerable promise for more specific antileukemic therapies. Here we summarize the latest insights into HSC niche biology and recent work showing multiple connections between hematological malignancy and alterations in the bone marrow microenvironment.     

Whewell’s tidal researches: scientific practice and philosophical methodology

Primarily between 1833 and 1840, William Whewell attempted to accomplish what natural philosophers and scientists since at least Galileo had failed to do: to provide a systematic and broad-ranged study of the tides and to attempt to establish a general scientific theory of tidal phenomena. I document the close interaction between Whewell’s philosophy of science (especially his methodological views) and his scientific practice as a tidologist. I claim that the intertwinement between Whewell’s methodology and his tidology is more fundamental than has hitherto been documented.     

Sperm competition, immunity, selfish genes and cancer

Sperm competition is widespread and has played an important role in shaping male reproductive characters such as testis size and numbers of sperm produced, and this is reflected in the rapid evolution of many reproductive genes. Additionally, sperm competition has been implicated in the rapid evolution of seminal fluids. However, our understanding of the molecular basis of many traits thought to be important in sperm competition is rudimentary. Furthermore, links between sperm competition and a range of issues not directly related to reproduction are only just beginning to be explored. These include associations between sperm competition and selfish genes, immunity and diseases such as cancer.We briefly review these topics and suggest areas we consider worthy of additional research.     

营口软土地区桩网复合地基沉降规律研究

为研究滨海软土地区高铁地基的沉降问题,以哈大高铁营口东站附近软土地基处理工程为研究对象,对路基填筑过程和工后长期地基沉降进行观测。利用有限元数值分析软件ADINA建立相应的数值计算模型,研究了地基表面沉降规律。研究表明：地基沉降主要发生在路基填筑施工期内,填筑期的沉降量占总沉降量的70％以上;路基填筑施工过程中,地基沉降曲线呈倒钟形,刺入现象明显,在CFG桩周沉降曲线呈“∩”形。基于现场实测数据,建立了工后长期地基沉降预测模型。对比分析结果表明,路基填筑完工三个月后（大约100d）预测公式精度较高,最终预测沉降量与观测值误差在0．21％～0．56％之间,可以满足工后长期沉降预测要求。上述研究成果将为处理滨海地区高速软土路基工程,预测和控制工后沉降提供了合理的依据。     

我国东南沿海热带气旋登陆地点的空间模式分析

应用网络空间点模式分析方法中的最邻近分析方法以及集聚分析方法,对1949年至2006年我国东南沿海地区热带气旋登陆点进行了分析研究。结果表明：我国东南沿海地区热带气旋登陆点在空间上倾向于集聚分布。根据集聚分析的结果将我国东南沿海地区划分为五个区段,其中登陆频率最高的为广东省雷州半岛到阳江段。本研究中的分段方法与传统方法比较表明,传统的经验分类方法注重的是行政区界限,空间统计方法的分段统计意义明显,分段更加科学合理。     

Fahraeus effect and Fahraeus-Lindqvist effect]

A series of experiments has been carried out on the flowing of suspended human erythrocytes into glass-tubes whose diameters varied between 30 mum and 1 mm. Thus, the Fahraeus and Fahraeus-Lindqvist effects emergence fields have been drawn, and it has been shown that, contrary to a widely admitted hypothesis, the Fahraeus effect does not account for the Fahraeus-Lindqvist effect.     

Shape change of human blood platelets: Reliable and fast detection by quasi-elastic light scattering

Quasi-elastic light scattering has been used for the first time to obtain reliable information about the morphology of platelets under physiological conditions within a short time. By measuring two independent parameters (electrophoretic mobility and diffusion coefficient) it is possible to distinguish between different stages of shape change on the one hand, and between shape change and binding of particles to the platelet surface without shape change on the other hand.     

Time-Symmetrised Quantum Theory,Counterfactuals and ‘Advanced Action’

Recent authors have raised objections to the counterfactual interpretation of the Aharonov–Bergmann–Lebowitz (ABL) rule of time-symmetrised quantum theory (TSQT). I distinguish between two different readings of the ABL rule, counterfactual and non-counterfactual, and confirm that TSQT advocate L. Vaidman is employing the counterfactual reading to which these authors object. Vaidman has responded to the objections by proposing a new kind of time-symmetrised counterfactual, which he has defined in two different ways. It is argued that neither definition succeeds in overcoming the objections, except in a limited special case previously noted by Cohen and Hiley. In addition, a connection is made between TSQT and Price’s concept of ‘advanced action’, which further supports the special case discussed.     

Shape change of human blood platelets: reliable and fast detection by quasi-elastic light scattering.

Quasi-elastic light scattering has been used for the first time to obtain reliable information about the morphology of platelets under physiological conditions within a short time. By measuring two independent parameters (electrophoretic mobility and diffusion coefficient) it is possible to distinguish between different stages of shape change on the one hand, and between shape change and binding of particles to the platelet surface without shape change on the other hand.     

Morphology of colloidal gold, ferritin and anti-ferritin antibody complexes.

The morphology of model complexes between colloidal gold, ferritin and anti-ferritin antibodies has been studied in order to evaluate the potential of colloidal gold as a cytochemical marker.     

Correlation between the intensity of spontaneous bacteriolysis and bacterial pollution in superficial waters]

A study on the determination of the intensity of spontaneous bacteriolysis in different samples of water from the hydrographic basin of Lorraine, has led us to propose a new way of expressing the spontaneous bacteriolytic power: PBSG. Its utilization has permitted us to establish correlations between the intensity of spontaneous bacteriolytic power and the degree of bacteriological pollution found in different places in the two rivers, the Moselle and the Meurthe. A very strong correlation has been shown between the rate of global spontaneous bacteriolysis after 6 days and the number of coliforms in the water.     

Evolutionary diversification of the mammalian defensins

Defensins are cysteine-rich cationic peptides that function in antimicrobial defense in both invertebrates and vertebrates. Three main groups of animal defensins are known: insect defensins; mammalian alpha-defensins and vertebrate beta-defensins. It has been difficult to determine whether these molecules are homologous or have independently evolved similar features, but overall the evidence favors a distant relationship. The best evidence of this relationship is structural, particularly from their overall three-dimensional structure and from the spacing of half-cystine residues involved in intra-chain disulfide bonds. Some evidence favors a closer relationship between vertebrate beta-defensins and insect defensins than between the two groups of vertebrate defensins. Examination of nucleotide substitutions between recently duplicated mammalian defensin genes shows that the rate of nonsynonymous (amino-acid-altering) substitution exceeds that of synonymous substitution in the region of the gene encoding the mature defensin. This highly unusual pattern of nucleotide substitution is evidence that natural selection has acted to diversify defensins at the amino acid level. The resulting rapid evolution explains why it is difficult to reconstruct the evolutionary history of these molecules.     

Was Feyerabend a Popperian? Methodological issues in the History of the Philosophy of Science

For more than three decades, there has been significant debate about the relation between Feyerabend and Popper. The discussion has been nurtured and complicated by the rift that opened up between the two and by the later Feyerabend's controversial portrayal of his earlier self. The first part of the paper provides an overview of the accounts of the relation that have been proposed over the years, disentangles the problems they deal with, and analyses the evidence supporting their conclusions as well as the methodological approaches used to process that evidence. Rather than advancing a further speculative account of the relation based on Feyerabend's philosophical work or autobiographical recollections, the second part of the paper strives to clarify the problems at issue by making use of a wider range of evidence. It outlines a historical reconstruction of the social context within which Feyerabend's intellectual trajectory developed, putting a special emphasis on the interplay between the perceived intellectual identity of Feyerabend, Feyerabend's own intellectual self-concept, and the peculiar features of the evolving Popperian research group.     

The role of conjugative transposons in spreading antibiotic resistance between bacteria that inhabit the gastrointestinal tract

There is huge potential for genetic exchange to occur within the dense, diverse anaerobic microbial population inhabiting the gastrointestinal tract (GIT) of humans and animals. However, the incidence of conjugative transposons (CTns) and the antibiotic resistance genes they carry has not been well studied among this population. Since any incoming bacteria, including pathogens, can access this reservoir of genes, this oversight would appear to be an important one. Recent evidence has shown that anaerobic bacteria native to the rumen or hindgut harbour both novel antibiotic resistance genes and novel conjugative transposons. These CTns, and previously characterized CTns, can be transferred to a wide range of commensal bacteria under laboratory and in vivo conditions. The main evidence that gene transfer occurs widely in vivo between GIT bacteria, and between GIT bacteria and pathogenic bacteria, is that identical resistance genes are present in diverse bacterial species from different hosts.     

On the role of divalent cations in the reaction mechanism of malic enzyme.

The kinetic order of addition of Mg2+ and L-malate to malic enzyme has been determined. Mg2+ is the first to bind, and probably acts as a link between the substrate and the active site.     

Differences in chromosome A arrangement between Drosophila madeirensis and Drosophila subobscura

The proximal half of the A (= X) chromosome of D. madeirensis has a gene arrangement very similar to the A1 or A6 inversions found in D. subobscura. Polytene chromosome analysis of hybrids between D. madeirensis and strains of D. subobscura homozygous for such inversions shows, however, that D. madeirensis has a gene arrangement different from any known for D. subobscura. These results provide evidence for a greater differentiation of the X chromosome in these species than has previously been described; it seems that the X chromosome is the only one that has undergone structural variation during the speciation process.