Multiple-interval mapping for ordinal traits

Many statistical methods have been developed to map multiple quantitative trait loci (QTL) in experimental cross populations. Among these methods, multiple-interval mapping (MIM) can map QTL with epistasis simultaneously. However, the previous implementation of MIM is for continuously distributed traits. In this study we extend MIM to ordinal traits on the basis of a threshold model. The method inherits the properties and advantages of MIM and can fit a model of multiple QTL effects and epistasis on the underlying liability score. We study a number of statistical issues associated with the method, such as the efficiency and stability of maximization and model selection. We also use computer simulation to study the performance of the method and compare it to other alternative approaches. The method has been implemented in QTL Cartographer to facilitate its general usage for QTL mapping data analysis on binary and ordinal traits.     

Mode of action of intercalators: a theoretical study

Mode of action of some intercalators has been theoretically investigated on the basis of quantum mechanical perturbation method. Energies of H-bond interaction between drug chromophore and base pairs have been calculated in all possible orientations. The stacking energy has also been calculated with the base pairs. The effect of these interactions on specific recognition has also been discussed. On the basis of these studies, a model for the interaction of these drugs has been proposed. This explains the relative activities of acridine intercalators and satisfies the experimental observations.     

Study on biogeographical divisions of China

On the basis of comprehensive natural factors (including altitude, landform, climate, vegetation, water system, farm belt, and so on), we first divide China's territory into 124 basic units by applying GIS techniques. Then 171 species of mammals and 509 of plants are selected for analysis on the basis of taxa with many representative species, wide distributions across China or thought to reveal biogeographic divisions in less well known parts of the country. We collected distribution data of these species through the China Species Information System, and utilized the GIS technique to identify in which of the 124 units each species has been recorded. The resulting data matrix was then arranged into dendrograms, aggregating the units at various levels on the basis of the mammal and plant distributions by application of similarity cluster analysis using both the Sørensen comparability index formula, and the Ward method to calculate correlation matrices. Finally, we summarize the different distribution characteristics of the aggregated units and their reasons of the two categories from these cluster dendrograms, and reach some important conclusions on the biogeographical regionalization of China. This research adopts a study method of starting from minimal basic units and then aggregating up to higher-level divisions, which is a new methodological attempt in the biogeographic division research field within China. By this method, the division boundaries can be determined by the cluster results of species distribution comparability rather than the limited species and ecology knowledge of an individual researcher as has been done in the past. This makes the resulting classification more objective and broader based. This method is also applicable to other biological taxa.     

Mechanisms of amino acid polycondensation on silica and alumina surfaces

Chemisorption products of bifunctional amino acid vapours on the surface of silica and alumina have been studied by the method of infrared spectroscopy. On the basis of the analysis of spectral data it is supposed that heterogeneous polycondensation of amino acids with formation of peptides proceeds under these conditions. The supposition was confirmed by the study of products of interaction of amino acid vapours with silica and alumina by the method of fast atom bombardment mass-spectrometry. It is established that in contrast to alumina the condensation of amino acids into linear peptides on silica surface proceeds only at presence of at least small amounts of water. The most probable mechanisms of extending of peptide chains are proposed on the basis of obtained experimental data.     

Identification of Land-Cover Characteristics Using MODIS Time Series Data: An Application in the Yangtze River Estuary

Land-cover characteristics have been considered in many ecological studies. Methods to identify these characteristics by using remotely sensed time series data have previously been proposed. However, these methods often have a mathematical basis, and more effort is required to better illustrate the ecological meanings of land-cover characteristics. In this study, a method for identifying these characteristics was proposed from the ecological perspective of sustained vegetation growth trend. Improvement was also made in parameter extraction, inspired by a method used for determining the hyperspectral red edge position. Five land-cover types were chosen to represent various ecosystem growth patterns and MODIS time series data were adopted for analysis. The results show that the extracted parameters can reflect ecosystem growth patterns and portray ecosystem traits such as vegetation growth strategy and ecosystem growth situations.     

Bayesian lasso for semiparametric structural equation models

There has been great interest in developing nonlinear structural equation models and associated statistical inference procedures, including estimation and model selection methods. In this paper a general semiparametric structural equation model (SSEM) is developed in which the structural equation is composed of nonparametric functions of exogenous latent variables and fixed covariates on a set of latent endogenous variables. A basis representation is used to approximate these nonparametric functions in the structural equation and the Bayesian Lasso method coupled with a Markov Chain Monte Carlo (MCMC) algorithm is used for simultaneous estimation and model selection. The proposed method is illustrated using a simulation study and data from the Affective Dynamics and Individual Differences (ADID) study. Results demonstrate that our method can accurately estimate the unknown parameters and correctly identify the true underlying model.     

Susceptibility of some weed species to Pepino mosaic virus (PepMV)

The aim of our investigations was to study the susceptibility of 22 weed species to Pepino mosaic virus (PepMV). Seven plants of each species were mechanically inoculated at 4-6 leaf stage with PepMV in a vector free virological glasshouse. Inoculated plants were tested on the basis of symptoms, by DAS ELISA serological method and back inoculation. Among the 22 weed species, only some Solanum ones (S. aethiopicum, S. dulcamara, S. luteum, S. nigrum) were susceptible to PepMV infection. All of them--except S. aethiopicum--belong to Hungarian weed flora, therefore these weeds--occurring mainly in tomato ecosystems--may play important role in the epidemiology of PepMV. Other 18 weed species seemed to be resistant to PepMV, and on the basis of back inoculation not even latent infection has been observed.     

用HLA基因频率计算人群间的遗传距离

本文用白细胞抗原(HLA)的基因频率按Nei氏法计算了中国11个民族和其他人种与国家的六个人群间的遗传距离,并按Sneath和Sokal氏聚类原则绘制了这些群体的系统树。得出的结果与用红细胞血型资料所计算的结果基本吻合,群体间遗传距离和群体分布的地理距离呈一定平行关系。     

Diagnostics of thyroid cancer: Limitations of the existing methods and perspectives for future developments

A novel approach to the development of a precise method of intraoperative diagnostics of thyroid cancer has been proposed on the basis of fundamental study of proteasomes in malignant tumors of mammals and human. The method is based on estimation of proteasome activity in small fragments of the tumor and adjacent tissues.     

The maltase activity of bovine serum as an aid to the study of the amylase i locus.

A method has been described for the detection of maltase activity in starch gels. This method has been used to resolve the difficulties encountered when analysing animals with weak AmIB activity for Ami genotype. It was found that, with the herd of the Hannah Research Institute, the heterozygote excess observed could be explained largely on the basis of these weak AmIB bands.     

Serological diagnosis of suppurative-septic diseases of staphylococcal etiology

The parallel examination of osteomyelitis patients by means of the passive hemagglutination (PHA) test with the use of antigenic erythrocyte diagnostic agents, prepared on the basis of hydrochloric acid extract from Staphylococcus aureus strain 209P and teichoic acid extract from S. aureus strain Wood 46 has revealed that these diagnostic agents are practically equal in their diagnostic effectiveness. In the examination of endocarditis patients measurement of the total antibody activity in the PHA test with diagnosticum on the basis of strain 209P has proved to be a more sensitive method, whereas in osteomyelitis patients the total IgG activity has been more accurately measured by ELISA. The treatment of sera with 2-mercaptoethanol essentially decreased the diagnostic effectiveness of the PHA test. The study has shown the diagnostic value of not only IgG but also of IgM antibody measurements.     

The maltase activity of bovine serum as an aid to the study of the Amylase I locus1

A method has been described for the detection of maltase activity in starch gels. This method has been used to resolve the difficulties encountered when analysing animals with weak AmIB activity for Ami genotype. It was found that, with the herd of the Hannah Research Institute, the heterozygote excess observed could be explained largely on the basis of these weak AmIB bands.     

Development of method to quantify extracellular carbohydrate complexes produced by Escherichia coli O157:H7

AIMS: The aim of this study was to optimize conditions to separate extracellular carbohydrate complexes (ECC) produced by Escherichia coli O157:H7 and to standardize the amount of ECC produced on a per cell basis. METHODS AND RESULTS: ECC fraction I was removed from E. coli O157:H7 cells produced on tryptic soya agar and lettuce juice agar by centrifugation. To remove ECC fraction II, cells were heated at 100 degrees C for 10 min, then centrifuged. The sum of ECC fractions I and II was considered as the total ECC produced by E. coli O157:H7. A correlation between cell mass and turbidity (O.D. 750 nm) of cell suspensions was determined. Cell mass has a linear relationship (R2 = 0.93) with turbidity of cell suspensions from which ECC is removed. The amount of ECC produced on a per cell basis was calculated by dividing total amount of ECC (microgram ml-1) produced by the turbidity (O.D. 750 nm) of heated cell suspension after removal ECC fractions I and II. CONCLUSIONS: A method for separating ECC from cells of E. coli O157:H7 has been developed and conditions have been optimized. A standard method to estimate the amount of ECC produced on a per cell basis was also developed. SIGNIFICANCE AND IMPACT OF THE STUDY: Using these procedures to prepare extract of ECC from E. coli O157:H7 and to standardize values, production of ECC on a per cell basis can be estimated and a comparison of the amount of ECC produced by the pathogen grown under different environmental conditions can be accurately measured.     

Isolation of monospecific Salmonella anti-O-4 antibodies by affinity chromatography and their use in immunoenzyme reactions

An immunosorbent with Salmonella typhimurium 1021 O-antigen has been obtained on the basis of polymer-modified porous glass. Binding has been effected due to the presence of NH2-groups on the carrier and aldehyde groupings on O-antigen previously oxidized with sodium periodate. Specific anti-O-4 antibodies have been isolated with the use of this immunosorbent, and on the basis of these antibodies peroxidase conjugates have been obtained. This preparation has made it possible to establish the parameters of EIA for the detection of Salmonella O-4 antigens in the assay involving the use of the sandwich technique. The method has proved to be sufficiently simple, sensitive and specific. It is recommended for the detection of Salmonella O-4 antigen in biological fluids.     

Concepts of nerve fiber development, 1839–1930

Conclusion It was thus the combination of observational and experimental approaches that ultimately led to confirmation of the outgrowth theory. The observational method was essential for defining various possible methods of nerve fiber development. The multicellular, protoplasmic bridge and outgrowth theories were each postulated to explain purely observational evidence. However, the lack of truly suitable equipment and techniques to study the developing nervous system made it impossible to agree on a single theory on this basis alone. The experimental method provided a means of choosing between these theories. Without the preceding observations that had led to the formulation of various hypotheses, however, the experimental approach might not have been so successful, for the power of this method is more of selection than of generation.Therefore it is impossible to weigh separately the contributions of the observational and experimental approaches to the question of nerve fiber development. Both were necessary for the ultimate acceptance of the outgrowth theory. *** DIRECT SUPPORT *** A8402051 00004     

Fenotypical characteristic of coagulase negative staphylococci isolated from patients hospitalized on burn ward and surgical ward

The aim of the study was to analysis of the adhesion factors of coagulase-negative staphylococci (CNS) to intravenous catheter: ability to adhesion, slime production, hydrophobicity of surface of cells and susceptibility to antibiotics. The researches heve been done on CNS strains isolated from cardiosurgical patients. Slime production ability was evaluated using plate method according to Christensen and Congo Red Agar method. Adherence of bacterial strains to intravenous catheter (polytetrafluoroethylene) in vitro was determined using the method of Richards. Hydrophobicity of surface of cells was determined on the basis of agregattion in (NH4)2SO4 Susceptibility to antibiotics was determined using the disc-diffusion method. Out of the analyzed strains 19% were labeled as slime producing in the plate method and 14% in the Congo red Agar method. 43% of analyzed strains were found to have TTC reduction of 3+, 19% of 2+ and 28% of 1+. Among these 10% of the assesed strains did not reduce TTC.     

Aspects of neural plasticity in the central nervous system—I. Computer-assisted image analysis methods

Microdensitometric and morphometric techniques have been developed to quantitatively characterize cell groups and terminal populations of transmitter-identified neuronal systems. Various microdensitometric methods implemented on the image analyzer or on the scanning microdensitometer were introduced and compared. On this basis a technique to assess the half-life of dopamine stores determined by quantitative immunocytochemistry has been developed. The problem of relative and absolute quantification of microdensitometric analysis of immunocytochemical preparations is discussed here. A method has been developed for the study, both in 2- and 3-dimensions, of the overall features of the profile distribution in a defined neuroanatomical area. An approach to determine the degree of uniformity of a certain profile distribution is also proposed. Furthermore, methods for the evaluation of the codistribution of two or more different types of profiles and to characterize the morphometric features of patches of profiles in a certain region are presented. All these quantitative morphological approaches were tested in relevant preparations of the central nervous system.     

Nutritional variation in Escherichia coli

Nutritional tests were carried out on 62 strains of Escherichia coli as part of a study on the genetic basis of natural nutritional variation. The ability of these strains to utilize 84 compounds as carbon, nitrogen and carbon plus nitrogen sources was tested using an auxanographic method. The tests revealed polymorphic characters which are suitable for genetic analysis. Very few of these strains grew on the amino acids classified as 'essential' for humans.     

Fine-Scale Genetic Mapping Based on Linkage Disequilibrium: Theory and Applications

Linkage-disequilibrium mapping (LDM) recently has been hailed as a powerful statistical method for fine-scale mapping of disease genes. After reviewing its historical background and methodological development, we present a general, mathematical, and conceptually coherent framework for LDM that incorporates multilocus and multiallelic markers and mutational processes at the marker and disease loci. With this framework, we address several issues relevant to fine-scale mapping and propose some efficient computational methods for LDM. We implement various LDM methods that incorporate population growth, recurrent mutation, and marker mutations, on the basis of a general framework. We demonstrate these methods by applying them to published data on cystic fibrosis, Huntington disease, Friedreich ataxia, and progressive myoclonus epilepsy. Since the genes responsible for these diseases all have been cloned, we can evaluate the performance of our methods and can compare ours with that of other methods. Using the proposed methods, we successfully and accurately predicted the locations of genes responsible for these diseases, on the basis of published data only.     

卫星景象目视解释方法在湖区植被制图中的应用——以湖南洞庭湖区水域、洲滩植被图为例

植被(包括天然植被、人工植被)作为一种可更新资源始终是遥感应用专家们热心研究的课题。植被分类是植被研究的重要方面之一。利用卫星影象进行植被分类,国内外学者都进行了许多有意义的探索。本文以洞庭湖水域、洲滩植被为对象,试用卫星影象进行植被分类。本文从植被与环境相互依赖关系及在影象上的综合反映出发,提出了影象的景观生态学分析方法;即把影象上色调、形态特征与群落生态学规律结合起来分析,并以此作为植被目视解译的方法论。在此基础上,将洞庭湖水域,洲滩划分成五个景观生态模型,17个基本植被类型。