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It is widely recognized that China is facing the dual challenge of food scarcity and water shortage. A large amount of water is to be demanded for the country’s huge population and rapid economic growth. The agricultural water footprint (AWF) proposes a new approach to indicate the interaction between food consumption and water utilization. This paper aims to quantify a long-time series of China’s AWF, map its variation trend, and assess its potential influence. The findings show that the total agricultural water footprint (TAWF) has increased from 7,593 km³ in 1990 to 10,929 km³ in 2011 due to increases in population and in per capita agricultural water footprint (CAWF). Over the past few years, China has also held an increasing external AWF volume, which climbed up to nearly 10% of the TAWF respectively in 2009, 2010, and 2011. The animal WF proportion of a single urban resident was much higher than that of a rural one because of their different consumption patterns, but neither of their proportions varied significantly over the same period of time. China’s CAWF increased over time and held a multi-year average value of 741 m³ ·cap⁻¹·y⁻¹. The results suggest that CAWF stayed linear positively related to the urban population proportion (UPP) during the study period and that urbanization proves to be the dominant driving force to the water requirement for food consumption augmentation. Considering the irresistible economic growth and urbanization, China should take active measures to cope with troubles potentially brought by the increase in AWF and water dependency degree (WDD). Suggestions with regard to how to guarantee China’s food and water resource security are raised in this paper.
High-throughput tag-sequencing (Tag-seq) from Illumina analysis, which is based on the Solexa Genome Analyzer platform, was applied to analyze the gene expression profiling of propamocarb (PM) treatment and control in cucumber fruit. Approximately 3.6 million complete clean sequence tags at PM treatment or control library were obtained with approximately 0.1 million distinct clean tag sequences. Approximately 41.79–43.15 % of the distinct clean tags were mapped unambiguously to the unigene database, and 32.54–33.46 % of the distinct clean tags were mapped to the cucumber genome database. The profiling analysis of the differentially expressed genes revealed the up-regulation of 546 genes and the downregulation of 185 genes with PM response. Furthermore, the differentially expressed genes mainly linked to pesticide detoxication, response to stress/stimulus, transporter/ signaling, and some important transcription factors. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) and reverse transcription polymerase chain reaction (RT-PCR) using 16 genes independently verified the tag-mapped results. The present study reveals the comprehensive mechanisms of PM response in cucumber fruit.
Identifying microbial yield and the pathway relating to nitrous oxide (N₂O) production in nitrification were essential prerequisites for modeling N₂O production and emissions. A thermodynamic method based on standard Gibbs free energy change of bio-chemical reaction was used to evaluate the NH₃-NO, NH₃-NO₂⁻ , NH₄⁺-NO, NH₄⁺-NO₂⁻ , NH₂OH-NO, and NH₂OH-NO₂⁻ reactions. Meanwhile, the stoichiometric equations of the relevant reactions were built up to ascertain the microbial yield of the microorganisms responsible for N₂O production. The results indicated that: 1) all the above reactions had the possibility of producing N₂O in nitrification as the standard Gibbs free energy changes of all the reactions were negative, 2) all the possible reactions can be used as the pathways to describe N₂O production in nitrification in mathematical models, and 3) theoretically, the yield coefficient of autotrophs relating to N₂O production was in the range of 0.097~0.194 g cell/ g N. Ammonia-oxidizing bacteria were responsible for the production of N₂O in nitrification. In order to develop a unified model for better simulation of N₂O production and emissions in the biological wastewater treatment process, intensive studies should be carried out to reveal undiscovered pathways relating to N₂O production.
Fly ash and ground iron ore tailings with fineness similar to cement were used as active and inert mineral admixtures in this study. This paper examines the compressive strength development of plain mortar and blend mortar containing fly ash and ground iron ore tailing. The mortar was cured at the same curing regime and a different water to cementitious material ratio was used. The autogenous shrinkage is also detected in the first seven days. At the early stage of hydration, fly ash and ground iron ore tailings played a role as physical filler during the hydration of the cementitious composites. As age increases, the pozzolanic reaction of fly ash became dramatic. Concrete with fly ash and ground iron ore tailings has a similar trend of autogenous shrinkage. As the amount of fly ash and ground iron ore tailings increases, autogenous shrinkage linearly decreases and their autogenous shrinkage is similar to each other. The autogenous shrinkage of concrete in one day is more than the total shrinkage of 80% in seven days.
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