Showing papers by "Yuhong Wang published in 2012"

The hierarchical configuration of the container port industry: an application of multiple linkage analysis

Abstract: This paper aims to provide a hierarchical configuration of the container port industry. It attempts to do so by determining a port hierarchy and then, utilising this, deriving the nature of the spatial interactions between sample ports in East Asia. The former is determined by assessing the relative importance of a port within the given network, and the latter is mainly based on the significance of network flow movements. Rather than focusing purely on the economic or topological meaning or significance of the available shipping capacity, this paper aims to determine port hierarchy by addressing the spatial profile of network flow data as a supplementary indicator. An approach based on graph theory—Multiple Linkage Analysis—is described and applied to examining the profile of capacity flow on each linkage within a sample network consisting of 39 major container ports on the main east–west routes. The value on a linkage is defined in terms of the available shipping capacity between pairs of ports within a ...

Costs and Effectiveness of Flexible Pavement Treatments: Experience and Evidence

Abstract: The authors investigated the effectiveness and costs of preventive treatment techniques for flexible pavements. Based on survey results from 29 state departments of transportation (DOTs), it was found that the expected pavement life extension caused by these treatments follows the order of thin hot-mix asphalt (HMA) overlay, microsurfacing tied with chip sealing, slurry sealing, and crack filling/sealing. The reported costs follow the order of thin overlay, microsurfacing, and chip sealing tied with slurry sealing, whereas costs of crack sealing/filling cannot be directly compared. The authors also analyzed data from 81 Long-Term Pavement Performance (LTPP) program specific pavement studies (SPS) experiments, which were specifically designed and constructed to study the effectiveness of pavement treatments. Based on paired t-tests, it was found that all the treatments reduced international roughness index (IRI) with statistical significance. The authors then pooled the data from all the control se...

Prices of Highway Resurfacing Projects in Economic Downturn: Lessons Learned and Strategies Forward

Abstract: It was observed that economic downturns were typically associated with oil price shocks. Based on historical construction data from highway resurfacing projects in Kentucky, this paper investigates the relationship between oil price, Kentucky diesel price index (KDPI), Kentucky asphalt price index (KAPI), and construction cost of highway resurfacing projects. It was found that the bidding price of a commonly used asphalt mixture was significantly affected by four factors: KDPI, KAPI, number of bidders, and a recession factor primarily attributable to the “sticky prices” effect. The KDPI and KAPI can be estimated from the oil price by regression models. The sensitivity of the asphalt mixture and resurfacing project costs to oil price variation was analyzed. On the basis of the analysis result, it is suggested that the highway agencies may avoid the oil price peak typically preceding a recession and take advantage of the oil price plunge after the recession starts. However, in the long run, the agen...

Individual chromosome identification, chromosomal collinearity and genetic-physical integrated map in Gossypium darwinii and four D genome cotton species revealed by BAC-FISH.

Abstract: The study was conducted on the individual chromosome identification in Gossypium darwinii (A(d)D(d)), G. klotzschianum (D(3k)), G. davidsonii (D(3d)), G. armourianum (D(2-1)) and G. aridum (D(4)) using a multi-probe fluorescence of in situ hybridization (FISH) system. Comparative analysis on their genetic maps with that of physical maps was made as well. The FISH probes used contained two sets of bacterial artificial chromosome (BAC) clones [one is specific to 26 individual chromosomes from A and D subgenomes of G. hirsutum (A(h) and D(h)) while the other is a D genome centromere-specific BAC clone 150D24], 45S and 5S rDNA clones. The results showed that all A(d) chromosomes were marked with the 13 A(h) chromosome-specific BAC clones, whilst all D(d), D(3k), D(3d), D(2-1) and D(4) chromosomes and chromosomal arms were identified with the 13 D(h) chromosome-specific BAC clones and the D genome centromere-specific BAC. According to the homology within D subgenomes which are between A (D) genome and A (D) subgenome, the systematic nomenclature for individual chromosome in the five species was established. The chromosomes of A (D) subgenomes in G. darwinii were named as A(d)01-A(d)13 (D(d)01-D(d)13). The chromosomes in D(3k), D(3d), D(2-1) and D(4) were named as D(3k)01-D(3k)13, D(3d)01-D(3d)13, D(2-1)01-D(2-1)13 and D(4)01-D(4)13, respectively. Based on the successful identification for individual chromosomes, 45S and 5S rDNA were located to the special chromosomes and chromosomal arms for all five species. And there appeared chromosomal collinearity from the BAC clones among different species by comparing BACs positions, which suggested that the majority of chromosome segment homology may exist between D genomes and D subgenome. Moreover, as the genetic map and physical map were integrated, the orientations of genetic maps for D(d) and D genomes of diploid cotton were established. The orientations of some of chromosomes in genetic maps (D(d)03, D(d)04, D(d)06, D(d)09, D(d)10 and D(d)12) were found switched. The SSR marker in the middle of linkage group 04 was corrected at nearby the end of chromosome 04 by FISH. The study will be helpful to establish a theoretical basis using the wild gene bank to exploit more genes aiming for cotton breeding and will provide powerful evidences both for the evolution of Gossypium and assembling the sequences of the obtained and as well the on-going whole genome sequencing projects of cotton.

Preparations of Meiotic Pachytene Chromosomes and Extended DNA Fibers from Cotton Suitable for Fluorescence In Situ Hybridization

Abstract: Fluorescence in situ hybridization (FISH) has become one of the most important techniques applied in plant molecular cytogenetics. However, the application of this technique in cotton has lagged behind because of difficulties in chromosome preparation. The focus of this article was FISH performed not only on cotton pachytene chromosomes, but also on cotton extended DNA fibers. The cotton pollen mother cells (PMCs) instead of buds or anthers were directly digested in enzyme to completely breakdown the cell wall. Before the routine acetic acid treatment, PMCs were incubated in acetic acid and enzyme mixture to remove the cytoplasm and clear the background. The method of ice-cold Carnoy's solution spreading chromosome was adopted instead of nitrogen removed method to avoid chromosomes losing and fully stretch chromosome. With the above-improved steps, the high-quality well-differentiated pachytene chromosomes with clear background were obtained. FISH results demonstrated that a mature protocol of cotton pachytene chromosomes preparation was presented. Intact and no debris cotton nuclei were obtained by chopping from etiolation cotyledons instead of the conventional liquid nitrogen grinding method. After incubating the nuclei with nucleus lysis buffer on slide, the parallel and clear background DNA fibers were acquired along the slide. This method overcomes the twist, accumulation and fracture of DNA fibers compared with other methods. The entire process of DNA fibers preparation requires only 30 min, in contrast, it takes 3 h with routine nitrogen grinding method. The poisonous mercaptoethanol in nucleus lysis buffer is replaced by nonpoisonous dithiothreitol. PVP40 in nucleus isolation buffer is used to prevent oxidation. The probability of success in isolating nuclei for DNA fiber preparation is almost 100% tested with this method in cotton. So a rapid, safe, and efficient method for the preparation of cotton extended DNA fibers suitable for FISH was established.

Grey prediction model‐based food security early warning prediction

Abstract: Purpose – The purpose of this paper is to make an evaluation and early warning prediction using grey prediction models and the index of process ability.Design/methodology/approach – An early warning prediction for food security risk is proposed in this paper. A quality index is constructed and an improved grey prediction model is also presented. The quality index model is applied to measure the level of food quality; then the grey prediction model is applied to predict the trend of quality index for food in the future. A comparison between the predicted trends and standard limit proposed by experts is made to judge the food security risk.Findings – The results in this paper indicate that more attention should be paid to the food security situation and steps should also should be taken to prevent harm to people's health from food.Practical implications – The method presented in the paper could be used to make predictions for those systems which have the characteristic of small sample and poor information. ...

Impact of Climate Conditions on Effectiveness of Asphalt Pavement Preservation Techniques

Abstract: Pavement preservation is practiced by many highway administration agencies throughout the world. Pavement preservation also attracts much attention from agencies that have few or no such programs. How to choose the most effective treatment at a given location, however, remains a question. On the basis of data from the Specific Pavement Study 3 of the Long-Term Pavement Performance program, the study reported in this paper examined the impact of climate conditions on the effectiveness of asphalt pavement preservation techniques. Six climate zones were defined on the bases of number of wet days, freeze-thaw cycles, and number of days below 0°C. Within each climate zone, performance differences on graphical representations and paired t-tests were assessed for four types of treatment sections and control sections in terms of the international roughness index (IRI). The magnitudes of the IRI changes caused by these treatments were in general quite noticeable, but the effectiveness varied greatly with climate c...

Role of the ribosomal protein L27 revealed by single‐molecule FRET study

Abstract: The ribosome is a ribozyme. However, in bacterial ribosomes, the N-terminus of L27 is located within the peptidyl transfer center. The roles of this protein in real time remain unclear. We present single-molecule fluorescence resonance energy transfer (FRET) studies of tRNA dynamics at the peptidyl transfer center in ribosomes containing either wild type (WT) L27, or L27 mutants with A2H3, A2H3K4 or nine N-terminal residues removed. Removing L27's first three N-terminal residues or mutating a single residue, K4, reduces the formation of a stable peptidyl tRNA after translocation. These results imply that L27 stabilizes the peptidyl tRNA and residue K4 contributes significantly to the stabilization.

Wintertime peroxyacetyl nitrate (PAN) in the megacity Beijing: the role of photochemical and meteorological processes

Abstract: . Peroxyacetyl nitrate (PAN) is one of the key photochemical pollutants and acts as an important reservoir for the peroxyacetyl (PA) radical and nitrogen oxides (NOx) over cold and less polluted regions. Previous measurements of PAN in Asian megacities were scarce and mainly conducted for relatively short periods in summer. In this study, we present and analyze the measurements of PAN, O3, NOx, CO, and some meteorological variables, made at an urban site (CMA) in Beijing from 25 January to 22 March 2010. During the observations, the hourly concentration of PAN varied from 0.23 to 3.51 ppb, with an average of 0.70 ppb. Both PAN and O3 showed small but significant diurnal cycle, with PAN peaking around 17:00 LT, three hours later than O3. The observed concentration of PAN is well correlated with that of NOx but not O3. These phenomena indicate that the variations of the winter concentrations of PAN and O3 in urban Beijing are decoupled with each other. Wind conditions and transport of air masses exert very significant impacts on O3, PAN, and other species. The strong WNW-N winds caused elevated concentrations of surface O3 and lower concentrations of PAN, NOx, and CO. Weak winds from the other directions led to enhanced levels of PAN, NOx, and CO and decreased level of O3. Air masses arriving at our site originated either from the boundary layer over the highly polluted N-S-W sector or from the free troposphere over the W-N sector. The descending free-tropospheric air was rich in O3, with an average PAN/O3 ratio smaller than 0.031, while the boundary layer air over the polluted sector contained higher levels of PAN and primary pollutants, with an average PAN/O3 ratio of 0.11. These facts related with meteorological conditions, specifically the air transport conditions, can well explain the observed PAN-O3 decoupling. The impact of meso-scale transport is demonstrated using a case during 21–22 February 2010. In addition to transport, photochemical production is important to PAN in the winter boundary layer over Beijing. The PA concentration is estimated from the measurements of PAN and related variables. The estimated PA concentration for three days with stable atmospheric condition, 7 February, 23 February, and 11 March, are in the range of 0–0.012, 0–0.036, and 0–0.040 ppt, respectively. We found that both the formation reaction and thermal decomposition contributed significantly to PAN's variation. The results here suggest that even in the colder period, both photochemical production and thermal decomposition of PAN in the polluted boundary layer over Beijing are not negligible, with the production exceeding the decomposition.

Long-Life Pavement Design and Construction: A Case Study

Abstract: Over the past 20 years, China's transportation infrastructure has developed rapidly. To date, more than 40,000 kilometers expressway have been built and opened to traffic, ranking second in the world. In the meantime, short service life and early failure of the highway pavement have become one of major concerns. This may be contributed by the poorly designed semi-rigid pavement structure and heavily overloaded vehicles. In more recent years, some long-life pavement structures have been designed and constructed. This paper discusses the design and construction of an expressway long-life flexible pavement structure in China. The project involved is a new 26.78 kilometer, Da'an to Jiliao Section in Henan Province, of the Erlianhaote to Guangzhou Expressway. The pavement had been designed as a semi-rigid structure which was later replaced by the new long-life flexible pavement structure in order to introduce this pavement technology as a cost-effective alternative to current semi-rigid or rigid pavement technology in China. Technical services provided through integrated technology transfer activities have presented a model for future expressway projects an option, and made the long-life flexible pavement structure the leading edge of national practice.

Method for identifying herbicide resistance of cotton leaves by cotton ball positioning

Abstract: The invention relates to plant physiology and pesticide science, in particular to a method for identifying herbicide resistance of cotton leaves by cotton ball positioning, which includes the steps: selecting material leaves for treatment, namely selecting intact functional leaves or leaves adjacent to those; secondly, cotton ball positioning, namely setting action spots on the front face of every functional leaf of each cotton plant clockwise or anticlockwise from a stipe, dipping cotton balls approximately in the same size with herbicide solutions having set concentrations, and sequentially placing the cotton balls dipped with the solutions having different concentrations at the corresponding action spots on the surface of each leaf; thirdly, observing action conditions of the treated spots to determine resistance levels of the spots. By the method, materials can be saved greatly, experimental scale can be reduced, artificial errors can be reduced greatly, results are precise and reliable, precision identification of the material resistance levels is technically guaranteed, and deep resistance research on current-generation material single plants is guaranteed. The method is quite simple in operation and easy to master.

Effects of asphalt on the enzymatic activity and bacterial community in soil

Abstract: Asphalt is an important material widely used in the coating of surfaces such as roads, roofs, linings of water basins and pipes, but it can be potentially hazardous to human and environment because certain substances exist in asphalt, including polycyclic aromatic hydrocarbons. However, it is unknown about the effect of asphalt on soil. The aim of this study is to examine the effects of asphalt on the physiochemical parameters, the enzymatic activity, and the copy number of 16s rRNA bacteria and archaea in soil. Freshly collected garden oils were amended with asphalt of various amounts after 1, 15 and 26 days, respectively. Asphalt application increased the total organic carbon, decreased the total phosphorus and pH values in soil while total nitrogen was not altered, suggesting asphalt can alter the nutrient composition. The copy number of 16s rRNA of bacteria increased in soil with addition of asphalt but that of archaea decreased. The activity of catalase, dehydrogenase, urease, sucrose, cellulase and polyphenol oxidase increased in soil modified with asphalt. Principal components analysis of these parameters resulted in three major components. Urease, sucrose, cellulose, bacteria, dehydrogenase, dehydrogenase, total organic carbon and total nitrogen weighed heavily in component 1, suggesting that the increase of organic carbon affect the enzymatic activity significantly. Although the asphalt may contain much toxic toxicity, asphalt can potentially improve the fertilization of the soil. Key words: Soil, asphalt, 16s rRNA, principal components analysis, bacteria.

Method for separating cotton PMC monosome and establishing specific molecular marker of cotton PMC monosome

Abstract: The invention relates to the field of molecular markers, in particular to a method for separating a cotton PMC monosome and establishing a specific molecular marker of the cotton PMC monosome. The method comprises the steps of selecting materials, identifying, performing micro-dissection on the target chromosome and the like and also comprises the steps of establishing a DNA bank by using the separated monosome as the material, cloning, randomly sequencing, developing the molecular marker by using marker software and positioning the marker on the specific chromosome of the cotton. The PMC cutting method can be implemented with the corresponding monomer material, wherein most of 26 chromosomes of the cotton have the corresponding monomer material at present. The PMC cutting is precise; false positive is low; the technology is difficult; the number of the metaphase cells as well as that of the target chromosomes is small; and one cell only has one chromosome.

Method for detecting and evaluating simple sequence repeat (SSR) molecular marker of crops

Abstract: The invention relates to the field of bioinformatics and particularly to a method for detecting and evaluating simple sequence repeat (SSR) molecular marker of crops, which can simultaneously analyze forward-direction sequence redundancy and backward-direction sequence redundancy of a pair of primers and can perform verification while performing electrophoresis level and sequencing sequence level. The existing method can only analyze the forward direction or the backward direction of a pair of primers, cannot analyze whether the pair of primers is redundant, and seqmatchall cannot analyze a reverse complementation sequence of the sequence, so that no proper software can analyze the redundancy of the pair of primers. The method develops a script program for large-scale analysis of SSR molecular marker redundancy, is favorable for researchers to fully utilize network resources, simultaneously improves working efficiency of the researchers and further lays a foundation for biology research.