31 research outputs found

    Hydrodeoxygenation of Guaiacol over Al-MCM-41 Supported Metal Catalysts: A Comparative Study of Co and Ni

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    AbstractThe hydrodeoxygenation (HDO) of guaiacol, a model compound of pyrolysis oil, was catalyzed by Al-MCM-41 supported Co and Ni catalysts in a fixed-bed continuous reactor at ambient pressure. The effects of contact time (W/F) and reaction temperature on HDO of guaiacol over the Co and Ni catalyst were studied. Cobalt showed higher activity than nickel in HDO via C−O hydrogenolysis pathway. The conversion of guaiacol over Ni catalyst principally occurred via C−C hydrogenolysis pathway, resulting in methane formation. Besides, the acidic Al-MCM-41 support catalyzed the methyl transfer reaction to form the methylated products. Additionally, increasing reaction temperature improved the HDO and suppressed the hydrogenation but promoted the methanization activities

    Encouraging Dialogue around Social Issues with Latinx Students Through Literature Discussion and Culturally Relevant Literature

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    This teacher research study examines literature discussions with fourth and fifth grade Latinx students about books that reflect Latinx experiences. For this study, the following questions are explored (1) What social issues do students discuss in literature groups? (2) How do literary response strategies influence student dialogue? And (3) How does my theoretical frame influence my decision making as a teacher? Theories that informed the construction of the literature discussions and the decision making occurring throughout the study are examined closely. The theories intertwine and bridge education and students’ experiences as a resource in learning more about the educational setting. In this study, the discussions of students and the literature response strategies are explored as the data is analyzed to examine the student discussions around issues of immigration, family separation, borders, and so much more. The findings in this study indicate that the experiences of Latinx students are integral to the educational setting and an education that invites who they are enhances their learning experiences. Latinx students are eager for learning opportunities that invite their voices and stories. It is through the construction and assessment of the educational setting that educators can promote culturally responsive, relevant, and sustaining teaching experiences that go beyond the classroom setting. Latinx students build relationships with each other and their teachers as they engage in discussions that allow them to share and learn with each other. This study is a reminder of the crucial role teachers play in creating such powerful spaces and the value that Latinx students bring into the classroom when invited to discuss, engage, and create powerful learning experiences

    Population structure, genetic connectivity, and signatures of local adaptation of the giant black tiger shrimp (Penaeus monodon) throughout the indo-pacific region

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    The giant black tiger shrimp (Penaeus monodon) is native to the Indo-Pacific and is the second most farmed penaeid shrimp species globally. Understanding genetic structure, connectivity, and local adaptation among Indo-Pacific black tiger shrimp populations is important for informing sustainable fisheries management and aquaculture breeding programs. Population genetic and outlier detection analyses were undertaken using 10,593 genome-wide single nucleotide polymorphisms (SNPs) from 16 geographically disparate Indo-Pacific P. monodon populations. Levels of genetic diversity were highest for Southeast Asian populations and were lowest for Western Indian Ocean (WIO) populations. Both neutral (n = 9,930) and outlier (n = 663) loci datasets revealed a pattern of strong genetic structure of P. monodon corresponding with broad geographical regions and clear genetic breaks among samples within regions. Neutral loci revealed seven genetic clusters and the separation of Fiji and WIO clusters from all other clusters, whereas outlier loci revealed six genetic clusters and high genetic differentiation among populations. The neutral loci dataset estimated five migration events that indicated migration to Southeast Asia from the WIO, with partial connectivity to populations in both oceans. We also identified 26 putatively adaptive SNPs that exhibited significant Pearson correlation (P < 0.05) between minor allele frequency and maximum or minimum sea surface temperature. Matched transcriptome contig annotations suggest putatively adaptive SNPs involvement in cellular and metabolic processes, pigmentation, immune response, and currently unknown functions. This study provides novel genome-level insights that have direct implications for P. monodon aquaculture and fishery management practices

    Fine-scale population structure and evidence for local adaptation in Australian giant black tiger shrimp (Penaeus monodon) using SNP analysis

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    Background: Restrictions to gene flow, genetic drift, and divergent selection associated with different environments are significant drivers of genetic differentiation. The black tiger shrimp (Penaeus monodon), is widely distributed throughout the Indian and Pacific Oceans including along the western, northern and eastern coastline of Australia, where it is an important aquaculture and fishery species. Understanding the genetic structure and the influence of environmental factors leading to adaptive differences among populations of this species is important for farm genetic improvement programs and sustainable fisheries management. Results: Based on 278 individuals obtained from seven geographically disparate Australian locations, 10,624 high-quality SNP loci were used to characterize genetic diversity, population structure, genetic connectivity, and adaptive divergence. Significant population structure and differentiation were revealed among wild populations (average FST = 0.001–0.107; p <  0.05). Eighty-nine putatively outlier SNPs were identified to be potentially associated with environmental variables by using both population differentiation (BayeScan and PCAdapt) and environmental association (redundancy analysis and latent factor mixed model) analysis methods. Clear population structure with similar spatial patterns were observed in both neutral and outlier markers with three genetically distinct groups identified (north Queensland, Northern Territory, and Western Australia). Redundancy, partial redundancy, and multiple regression on distance matrices analyses revealed that both geographical distance and environmental factors interact to generate the structure observed across Australian P. monodon populations. Conclusion: This study provides new insights on genetic population structure of Australian P. monodon in the face of environmental changes, which can be used to advance sustainable fisheries management and aquaculture breeding programs

    Prevalence of Arboviruses in Vietnam

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    For many years, arbovirus infections have been a global health problem and one of the urgent threats to the sanitary and epidemiological well-being of the population. Climatic conditions, species diversity and abundance of vectors, epidemiological and demographic factors are of fundamental importance for the emergence and persistence of natural foci of arbovirus infections. In the Socialist Republic of Vietnam (SRV) and other countries of the Asia-Pacific region, the most complex epidemiological situation is observed in regard to a number of arboviral infectious diseases transmitted by mosquitoes, inter alia to dengue fever. In this review we analyzed the literature data to identify the features of the circulation of some arboviruses in Vietnam, such as dengue virus, Zika, Chikungunya, Japanese encephalitis virus, Dabie virus, and the routes of their transmission and spread. It is shown that the climatic, ecological, epidemiological and demographic conditions existing on the territory of Vietnam contribute to the spread of pathogens of many arboviruses. Areas of more active circulation and ways of spreading pathogens of arbovirus infections have been identified. Based on the data obtained, it is necessary to conduct annual epidemiological and epizootiological survey of the territory of the SRV in order to identify markers of pathogens and determine the boundaries of natural foci of arbovirus infectious diseases which will enhance and increase the effectiveness of preventive and anti-epidemic measures

    Development and impact of site specific nutrient management in the Red River Delta of Vietnam

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    Site-specific nutrient management (SSNM) for a more effective use of fertilizers in rice production was developed and validated in the Red River Delta (RRD) of northern Vietnam through a partnership of the Soils and Fertilizers Research Institute (SFRI) and the International Rice Research Institute (IRRI) beginning in 1997. The subsequent dissemination of validated SSNM practices involved collaboration of SFRI and IRRI with the extension system and Plant Protection Division (PPD). We review the development of SSNM in the RRD and estimate the impact of SSNM adoption at the farm level through a survey in 2007 of adopters and nonadopters of SSNM in Ha Nam and Ha Tay provinces. SSNM improved farmers' rice yield by 0.2 t ha-1 in Ha Nam and by 0.34 t ha-1 in Ha Tay in the spring season. SSNM adopters appeared to have improved fertilizer management. SSNM increased net annual income by US57ha−1inHaTayandby57 ha-1 in Ha Tay and by 78 ha-1 in Ha Nam. Simple projections for the wide application of SSNM throughout the RRD indicate potential annual gains of 228,000 tons of additional unmilled rice. Based on frontier production functions, adopters achieved a slightly higher index of technical efficiency in rice production. SSNM improved farmers' knowledge, attitudes, and skills in rice farming
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