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

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

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

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

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)

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

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

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

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

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

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

ACUTE: Attentional Communication Framework for Multi-Agent Reinforcement Learning in Partially Communicable Scenarios

Multi-agent reinforcement learning (MARL) aims to study the behavior of multiple agents in a shared environment. Existing communication-based MARL methods seldom consider the case of communication interference. However, such situations are not rare in real-world inter-agent communication. The majority of previous MARL methods struggle to design effective communication techniques for better cooperation between agents without considering communication reliability or channel capacity constraints. In addition, these models are typically not ready to be extended to large-scale multi-agent systems. To address these issues, in this paper, we propose a method named the Attentional CommUnicaTion FramEwork (ACUTE), which enables efficient communication between agents in a dynamic environment and improves the effectiveness of decision-making by using the most useful information from other agents. Specifically, we introduce an attention mechanism for the feature extraction of information during communication which determines the importance of messages received by agents. We evaluate the performance of our approach under different channel capacity constraints. Experimental results show that our model can efficiently exploit messages transmitted in unreliable channels for higher returns when compared to existing methods and can be applied to large-scale multi-agent systems

ACUTE: Attentional Communication Framework for Multi-Agent Reinforcement Learning in Partially Communicable Scenarios

Multi-agent reinforcement learning (MARL) aims to study the behavior of multiple agents in a shared environment. Existing communication-based MARL methods seldom consider the case of communication interference. However, such situations are not rare in real-world inter-agent communication. The majority of previous MARL methods struggle to design effective communication techniques for better cooperation between agents without considering communication reliability or channel capacity constraints. In addition, these models are typically not ready to be extended to large-scale multi-agent systems. To address these issues, in this paper, we propose a method named the Attentional CommUnicaTion FramEwork (ACUTE), which enables efficient communication between agents in a dynamic environment and improves the effectiveness of decision-making by using the most useful information from other agents. Specifically, we introduce an attention mechanism for the feature extraction of information during communication which determines the importance of messages received by agents. We evaluate the performance of our approach under different channel capacity constraints. Experimental results show that our model can efficiently exploit messages transmitted in unreliable channels for higher returns when compared to existing methods and can be applied to large-scale multi-agent systems

Effects of grazing on the allocation of mass of soil aggregates and aggregate-associated organic carbon in an alpine meadow.

Soil aggregation is closely related to the soil organic carbon sequestration, both of which plays an important role in the stability of the soil carbon pool. However, the results of the impact of yak grazing intensity on the soil carbon process in alpine meadows have been unclear. With the marsh meadow as the research object in the Gahai wetland of the east Qinghai-Tibet Plateau, we analyzed the influence of different grazing intensities on the allocation of mass, stability and aggregate-associated organic carbon content of aggregates in the surface soil (0-20cm) of pasture by the Le Bissonnais method. The results showed that the mass of aggregates in the particle size class of > 0.2-mm was the highest among the pastures with different grazing intensities. Compared with the no grazing grassland, light grazing promoted the formation of macro aggregates in the particle size class of > 1-mm and improved the stability of soil aggregates. The degree of soil agglomerations and stability of aggregates decreased, and the macro aggregates gradually transformed into micro aggregates ( 2-mm and 0.05). This result shows that light grazing, which is a reasonable yak grazing intensity in the study area, is conducive to the formation of a good soil structure in the area and improves the soil carbon sequestration capacity