16 research outputs found

    Genomic Insights Into The Ixodes scapularis Tick Vector Of Lyme Disease

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    Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retrotransposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing B57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick–host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host ‘questing’, prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent

    Genomic Insights Into The Ixodes scapularis Tick Vector Of Lyme Disease

    Get PDF
    Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retrotransposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing B57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick–host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host ‘questing’, prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent

    Assessing Factors Driving the Change of Irrigation Water-Use Efficiency in China Based on Geographical Features

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    Changes in irrigation water-use efficiency are related closely to agricultural development. Clarifying the driving factors of irrigation water-use efficiency change at different agricultural development stages is beneficial for buffering the contradiction between the protection of water resources and massive agricultural water consumption. It also has theoretical and application value when it comes to elucidating the driving characteristics of spatial changes in irrigation water-use efficiency observed among the different provinces of China. This paper analyzes driving factors of irrigation water-use change based on a study of literature and a field survey. It selects 21 indices from five aspects of climatic change, resource endowment, economic situation, technological level, and management mode as the system of driving factors for irrigation water-use change. This article then uses statistical data on economic and social development in the 31 provinces of China in 2009, and applies the principal component analysis (PCA) method to extract the main driving factors affecting irrigation water-use efficiency change. After calculation of factor scores, clustering analysis is conducted on the 31 provinces to explore regional differences among the driving factors of irrigation water-use efficiency change. The results show that these can be attributed to the factors of agricultural economic development, water-saving irrigation technology, water resource endowment, and dissipation. The 31 provinces can be divided into five types: agricultural economy strong driving type; agricultural economy dominant type; industrial economy dominant type; agriculture strong development type; and coordinated driving type. In highly agricultural provinces, mature irrigation district management and water-saving measures influence the efficiency of irrigation water-use, making these strong positive driving factors. In highly industrial provinces, changes in irrigation water-use efficiency are mainly driven by economic development and structural adjustment, making these weak driving factors

    Research on the Influencing Factors of Comprehensive Water Consumption by Impulse Response Function Analysis

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    Jiangsu is a major province located in the east of China, consuming a large amount of water resources. It is considered that improving the comprehensive water use efficiency has an important significance to achieve sustainable development of the economy in Jiangsu. Through extensive literature research and investigation of Jiangsu Province, this paper establishes comprehensive water use efficiency index system using water consumption per ten thousand dollar gross domestic product (WC/104GDP)astheresearchtarget.Intheindexsystem,resourcefactorssuchassurfacewaterresources(SW),groundwaterresources(GW),precipitation(PT),waterresourcespercapita(PW),waterconsumptionpercapita(PC)andirrigationareapercapita(PI)cannotbeartificiallyaltered.Furthermore,thevariationamplitudeofresourcefactorsisverysmall.Itshowsthatthelinearregressionmodelisnotsuitabletoanalyzetheresourcefactorsbychangingtheindependentvariables.Inviewofthissituation,thispaperintroducesimpulseresponsefunctiononthebasisofvectorautoregressivemodel(VAR)toinvestigatetheintrinsiclinkbetweenresourcefactorsandWC/104 GDP) as the research target. In the index system, resource factors such as surface water resources (SW), groundwater resources (GW), precipitation (PT), water resources per capita (PW), water consumption per capita (PC) and irrigation area per capita (PI) cannot be artificially altered. Furthermore, the variation amplitude of resource factors is very small. It shows that the linear regression model is not suitable to analyze the resource factors by changing the independent variables. In view of this situation, this paper introduces impulse response function on the basis of vector autoregressive model (VAR) to investigate the intrinsic link between resource factors and WC/104 GDP in Jiangsu Province. The results show that resource factors have a great impact on WC/$104 GDP in Jiangsu, and the per capita water resources (PW) has the most significant impact

    Driven Factors Analysis of China’s Irrigation Water Use Efficiency by Stepwise Regression and Principal Component Analysis

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    This paper introduces an integrated approach to find out the major factors influencing efficiency of irrigation water use in China. It combines multiple stepwise regression (MSR) and principal component analysis (PCA) to obtain more realistic results. In real world case studies, classical linear regression model often involves too many explanatory variables and the linear correlation issue among variables cannot be eliminated. Linearly correlated variables will cause the invalidity of the factor analysis results. To overcome this issue and reduce the number of the variables, PCA technique has been used combining with MSR. As such, the irrigation water use status in China was analyzed to find out the five major factors that have significant impacts on irrigation water use efficiency. To illustrate the performance of the proposed approach, the calculation based on real data was conducted and the results were shown in this paper

    Optimization of refined oil logistics considering pipeline-rail combined transportation

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    The optimization of oil depot inventory is focused in most of the previous researches on the optimization of refined oil logistics, but the reasonable choice of transportation mode and the influence of batch transportation on pipeline transport plan are not considered during decision-making. On this basis, an optimization model of refined oil logistics was constructed under the premise of satisfying the demand of oil products at the oil depot, establishing the objective function of minimizing overall transportation cost and considering the constraints of oil depot demand, storage capacity and transportation capacity. Meanwhile, a pipeline scheduling optimization model was also constructed by setting up the objective function of minimizing the sum of deviations between the actual delivery volume of oils and the demand of the delivery stations along the pipeline, with consideration to the constraints of batch tracking, batch delivery and node flow. Finally, a refined oil logistics plan satisfying the transportation capacity of pipeline was obtained by coupling the above two models into an optimization model of refined oil logistics, considering the pipeline-rail combined transportation, and iteratively solving the logistics plan and pipeline scheduling plan. Specifically, the constructed model was applied to the formulation of a regional logistics plan for refined oil. The optimization results show that the pipeline transportation volume is improved, the mileage of railway transportation is shortened, and the overall logistics cost is reduced by 4.18% compared with the site plan. The research results have some guiding significance for the refined oil marketing enterprises to develop a reasonable logistics plan

    Adaptability analysis and planning of green ammonia and product oil integrated transmission system

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    [Objective] Ammonia is acknowledged as an efficient hydrogen storage medium, having the potential of being a substitute for fossil fuels in achieving the vision of a “carbon-free future”. Due to its stable liquid-state attributes in storage and transport, establishing a transmission system integrating green ammonia and product oil using in-service product oil pipelines is of important significance for fostering a green ammonia industry chain. [Methods] This paper began with a comprehensive introduction to background information,including the production capacity distribution of green ammonia in China, the pros and cons of different transportation modes, and the potentiality of integrating liquid ammonia transmission into in-service product oil pipelines. Then the adaptability of the system in integrating liquid ammonia transmission was analyzed from six dimensions: properties of transmission mediums, long-distance pipeline structure, pipes and equipment, pipeline transmission technology, hydraulic calculation method, and safety considerations related to operational pressure and fow rates. Considering the coupling characteristics of green ammonia and product oil during transportation, a conceptual plan was outlined for establishing green ammonia and product oil integrated transmission systems based on the supply and demand patterns of “westeast ammonia transmission” and “north-south ammonia transmission”. [Results] As the production capacity of green ammonia continuously expands, pipelines have emerged as the preferred mode for long-distance transportation. Moreover, given the underutilized transmission capacity of existing product oil pipelines, notable potential exists in integrating liquid ammonia transmission into these pipelines to enhance economic benefits. Theoretically, current product oil pipelines bear striking resemblance to existing long-distance liquid ammonia pipeline systems, so they are capable of meeting specific requirements for liquid ammonia transport when offered with technological or equipment upgrades. Therefore, under the premise of implementing rational pressure and flow rate control strategies, the system integrating liquid ammonia transmission into operational product oil pipelines exhibits robust adaptability, necessitating further experimental validation of their feasibility. This paper envisioned the potential of these integrated systems across four key aspects: planning for green ammonia and product oil integrated transmission systems, optimization through collaboration of multiple transportation modes, defining operational boundaries for liquid ammonia pipeline transmission, and optimization of pipeline transmission batches. [Conclusion] The study outcomes can serve as a valuable reference for promoting the healthy development of the green ammonia industry and enhancing the safety and economic efficiency of green ammonia and product oil integrated transmission systems
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