133 research outputs found

    Grasslands Are My Home: An Innovative Primary School Program Developed for Remote Chinese Villages

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    Environmental education is a useful tool for changing the mind-set of people and it has been developed over many years and in many countries. This paper reports the environmental education program funded by World Bank/GEF pastoral development project in northwest China. The involved writing training materials for students and teachers, teaching in classroom, practicing in filed, and interactions with parents. The purpose of the environmental education program was training a student to influence the whole family, educate a class and help manage a community. The result showed that the environmental education program had positive impact on student attitudes toward environmental protection

    Network Embedding-Based Anomalous Density Searching for Multi-Group Collaborative Fraudsters Detection in Social Media

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    Detecting collaborative fraudsters who manipulate opinions in social media is becoming extremely important in order to provide reliable information, in which, however, the diversity in different groups of collaborative fraudsters presents a significant challenge to existing collaborative fraudsters detection methods. These methods often detect collaborative fraudsters as the largest group of users who have the strongest relation with each other in the social media, consequently overlooking the other groups of fraudsters that are with strong user relation yet small group size. This paper introduces a novel network embedding-based framework NEST and its instance BEST to address this issue. NEST detects multiple groups of collaborative fraudsters by two steps. In the first step, to disclose user collaboration, it represents users according to their social relations. Then, in the second step, to identify the collaborative fraudsters, it detects the user groups with anomalous large group density in its representation space. BEST instantiates NEST by using a bipartite network embedding method to represent users and adopting a fast density group detection method based on the k-dimensional tree. Our experiments show BEST (i) performs significantly better in detecting fraudsters on four real-word social media data sets, and (ii) effectively detects multiple groups of collaborative fraudsters, compared to three state-of-the-art competitors

    Stereoselective Syntheses of Deuterated Pipecolic Acids as Tools to Investigate the Stereoselectivity of the Hydroxylase GetF

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    Members of the GE81112 family are interesting candidates for the development of antibiotics. The configuration of the OH group on the pipecolic acid moiety plays a pivotal role in antibiotic activity. To investigate the stereoselectivity of the corresponding hydroxylase GetF, involved in the biosynthetic pathway, we synthesized the two deuterium-labeled pipecolic acid diastereomers in a highly stereoselective fashion via chelate-enolate Claisen rearrangement. The stereochemical outcome of the enzymatic hydroxylation step could easily be determined by analysis of mass differences between the products

    Stereoselective Syntheses of Deuterated Pipecolic Acids as Tools to Investigate the Stereoselectivity of the Hydroxylase GetF

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    Members of the GE81112 family are interesting candidates for the development of antibiotics. The configuration of the OH group on the pipecolic acid moiety plays a pivotal role in antibiotic activity. To investigate the stereoselectivity of the corresponding hydroxylase GetF, involved in the biosynthetic pathway, we synthesized the two deuterium-labeled pipecolic acid diastereomers in a highly stereoselective fashion via chelate-enolate Claisen rearrangement. The stereochemical outcome of the enzymatic hydroxylation step could easily be determined by analysis of mass differences between the products

    A BAC-Based Physical Map of Zhikong Scallop (Chlamys farreri Jones et Preston)

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    Zhikong scallop (Chlamys farreri) is one of the most economically important aquaculture species in China. Physical maps are crucial tools for genome sequencing, gene mapping and cloning, genetic improvement and selective breeding. In this study, we have developed a genome-wide, BAC-based physical map for the species. A total of 81,408 clones from two BAC libraries of the scallop were fingerprinted using an ABI 3130xl Genetic Analyzer and a fingerprinting kit developed in our laboratory. After data processing, 63,641 (∼5.8× genome coverage) fingerprints were validated and used in the physical map assembly. A total of 3,696 contigs were assembled for the physical map. Each contig contained an average of 10.0 clones, with an average physical size of 490 kb. The combined total physical size of all contigs was 1.81 Gb, equivalent to approximately 1.5 fold of the scallop haploid genome. A total of 10,587 BAC end sequences (BESs) and 167 markers were integrated into the physical map. We evaluated the physical map by overgo hybridization, BAC-FISH (fluorescence in situ hybridization), contig BAC pool screening and source BAC library screening. The results have provided evidence of the high reliability of the contig physical map. This is the first physical map in mollusc; therefore, it provides an important platform for advanced research of genomics and genetics, and mapping of genes and QTL of economical importance, thus facilitating the genetic improvement and selective breeding of the scallop and other marine molluscs

    Comprehensive evaluation of the nutritional value and contaminants of alfalfa (Medicago sativa L.) in China

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    IntroductionAlfalfa is used as a feed source for animals and plays an important role in animal nutrition. Nutritional value analysis and contamination evaluation are essential for sustainable utilisation to ensure the quality and safety of alfalfa.AimWe aimed to evaluate the nutritional value and safety of alfalfa in five major regions in China—the Northeast Plain (NP), Inner Mongolia Plateau (IMP), Northwest Desert Oasis (NO), Loess Plateau (LP), and Huanghuaihai Plain (HP).MethodsNinety-five samples representing 44 large-scale pratacultural companies were collected and analysed.ResultsThe average nutritional values of alfalfa hay were 16.43% crude protein (CP), 44.01% neutral detergent fibre (NDF), 33.22% acid detergent fibre (ADF), 10.78% crude ash (Ash), and 91.90% dry matter (DM), which were better in the NO and IMP areas; in particular, the α-linolenic acid value of alfalfa was the highest in the IMP area (p < 0.05). The detection rates of mycotoxins, microorganisms, and heavy metals were 100%. The over-standard rates of total bacteria count and total mould count were 66.7% and 75.8%, respectively, while the over-standard rate of chromium in heavy metals was as high as 87.9%.DiscussionThis study establishes the nutrient composition and harmful component profiles of alfalfa hay in five major planting areas for the first time, which provides a valuable reference for the safe and sustainable utilisation of alfalfa in livestock feed

    Single-atom tailoring of platinum nanocatalysts for high-performance multifunctional electrocatalysis

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    Platinum-based nanocatalysts play a crucial role in various electrocatalytic systems that are important for renewable, clean energy conversion, storage and utilization. However, the scarcity and high cost of Pt seriously limit the practical application of these catalysts. Decorating Pt catalysts with other transition metals offers an effective pathway to tailor their catalytic properties, but often at the sacrifice of the electrochemical active surface area (ECSA). Here we report a single-atom tailoring strategy to boost the activity of Pt nanocatalysts with minimal loss in surface active sites. By starting with PtNi alloy nanowires and using a partial electrochemical dealloying approach, we create single-nickel-atom-modified Pt nanowires with an optimum combination of specific activity and ECSA for the hydrogen evolution, methanol oxidation and ethanol oxidation reactions. The single-atom tailoring approach offers an effective strategy to optimize the activity of surface Pt atoms and enhance the mass activity for diverse reactions, opening a general pathway to the design of highly efficient and durable precious metal-based catalysts

    Spatial Dynamics and Determinants of Population Urbanization in the Upper Reaches of the Yellow River

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    The spatiotemporal evolution of population urbanization and its relationship with economic variables are important aspects of socioeconomic research and essential for revealing the mechanism of urban construction and evolution. To study the spatial heterogeneity and influencing mechanisms of population urbanization in the upper reaches of the Yellow River, this study investigated the spatial distribution and dynamic evolution of population urbanization using nuclear density analysis, exploratory spatial data analysis and the geographical detector model. The results showed that the rate of population urbanization in the upper reaches of the Yellow River increased annually since 2000 and that the nuclear density curve changed from a single–peaked mode in 2000 to a double–peaked mode in 2018. The spatial distribution of the population urbanization level was uneven, that is, high in the north and low in the south, with substantial spatial agglomeration and spatial autocorrelation. The main distribution of hot spots was in the Yinchuan area in the north, while cold spots were distributed mainly in the south. Analysis revealed that changes in population urbanization level were mainly attributable to the influence of economic and employment opportunities, such as regional GDP, GDP per capita, proportion of tertiary industry in GDP, and total retail sales of consumer goods
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