Water and sediment quality in Qinghai Lake, China: a revisit after half a century.

Qinghai Lake, situated on the Qinghai-Tibet plateau, is the largest lake in China. In this study, the water and sediment quality were investigated in Qinghai Lake, three sublakes, and five major tributaries. Both Na+ and Cl- were found to be the major ions present in Qinghai Lake and the three sublakes, while Ca2+ and HCO3- dominated the tributaries. Compared with historical data from the 1960s, the concentrations of NH4 (+), NO3 (-), and soluble reactive silica have increased considerably, likely caused by increased human activities in the area. Compared to the historical data, chemical oxygen demand has increased and lake water transparency has decreased, likely related to an increase in nutrient levels. Relatively high concentrations of total nitrogen (TN) and total phosphorus (TP) were observed in Qinghai Lake sediments, although P fraction types and low water concentrations of these two indicate low possibility of transfer into the water column. The ratios of C/N suggest that the organic matter in the sediments are primarily from autochthonous sources. TN and total organic carbon in the sediment cores increased slowly up the core while TP and total inorganic carbon have been fairly constant

A Meta-Analysis of the Bacterial and Archaeal Diversity Observed in Wetland Soils

This study examined the bacterial and archaeal diversity from a worldwide range of wetlands soils and sediments using a meta-analysis approach. All available 16S rRNA gene sequences recovered from wetlands in public databases were retrieved. In November 2012, a total of 12677 bacterial and 1747 archaeal sequences were collected in GenBank. All the bacterial sequences were assigned into 6383 operational taxonomic units (OTUs 0.03), representing 31 known bacterial phyla, predominant with Proteobacteria (2791 OTUs), Bacteroidetes (868 OTUs), Acidobacteria (731 OTUs), Firmicutes (540 OTUs), and Actinobacteria (418 OTUs). The genus Flavobacterium (11.6% of bacterial sequences) was the dominate bacteria in wetlands, followed by Gp1, Nitrosospira, and Nitrosomonas. Archaeal sequences were assigned to 521 OTUs from phyla Euryarchaeota and Crenarchaeota. The dominating archaeal genera were Fervidicoccus and Methanosaeta. Rarefaction analysis indicated that approximately 40% of bacterial and 83% of archaeal diversity in wetland soils and sediments have been presented. Our results should be significant for well-understanding the microbial diversity involved in worldwide wetlands.This study examined the bacterial and archaeal diversity from a worldwide range of wetlands soils and sediments using a meta-analysis approach. All available 16S rRNA gene sequences recovered from wetlands in public databases were retrieved. In November 2012, a total of 12677 bacterial and 1747 archaeal sequences were collected in GenBank. All the bacterial sequences were assigned into 6383 operational taxonomic units (OTUs 0.03), representing 31 known bacterial phyla, predominant with Proteobacteria (2791 OTUs), Bacteroidetes (868 OTUs), Acidobacteria (731 OTUs), Firmicutes (540 OTUs), and Actinobacteria (418 OTUs). The genus Flavobacterium (11.6% of bacterial sequences) was the dominate bacteria in wetlands, followed by Gp1, Nitrosospira, and Nitrosomonas. Archaeal sequences were assigned to 521 OTUs from phyla Euryarchaeota and Crenarchaeota. The dominating archaeal genera were Fervidicoccus and Methanosaeta. Rarefaction analysis indicated that approximately 40% of bacterial and 83% of archaeal diversity in wetland soils and sediments have been presented. Our results should be significant for well-understanding the microbial diversity involved in worldwide wetlands

立體電腦動畫技術在教學上的應用研究

工藝教育研究所

A reappraisal of the ink-bottle effect and pore structure of cementitious materials using intrusion-extrusion cyclic mercury porosimetry

Reliable characterization of the pore structure is essentially important for transport-related durability studies of cementitious materials. Mercury intrusion porosimetry has been commonly used for pore structure measurement while the ink-bottle effect significantly affects the trustworthiness of pore size features of cementitious materials. Pressurization-depressurization cycling mercury intrusion porosimetry (PDC-MIP) is an alternative approach previously reported with the purpose to provide better estimates of pore size results. It is found however that the PDC-MIP greatly overestimates the ink-bottle pore volume owing to the incomplete extrusion of mercury in throat pores after the pressurization-depressurization cycle. Intrusion-extrusion cyclic mercury porosimetry (IEC-MIP), as a further improvement, is then described, which can reliably capture the ink-bottle effect and obtain a clear picture of the distribution of the ink-bottle pores in cementitious materials. The ink-bottle effect of cement pastes is observed being pore size-dependent and the role of critical pores is emphasized. Water-cement ratio primarily changes the effective porosity while plays a minor role in the ink-bottle porosity. The addition of reactive blends substantially enhances the ink-bottle effect during mercury penetration into small pores. IEC-MIP tests, together with a unique data analysis, enable to obtain a more truthful pore size distribution.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and Environmen

Effect of water deficit on growth and photosynthetic characteristics of 13 winter wheat

Wheat is one of the major crops in the world and is rather sensitive to water deficit and differences between genotypes for water tolerance have been previously testified. Experiment was conducted in a greenhouse with 13 cultivars grown in control and water deficit conditions. Gas exchange, chlorophyll fluorescence parameters, above ground biomass and total leaf area were measured to determine water tolerance. Drought susceptibility indexes were used to estimate the relative tolerance of wheat cultivars to water deficit. Water deficit decreased total leaf area, above-ground biomass, net photosynthesis, stomatal conductance, internal CO(2) concentration and the actual quantum yield of PS II electron transport relative to cultivars that were grown under control condition. Measurement of stomatal conductance provided useful information to assess genetic differences in wheat for absolute performance when subjected to water deficit. Besides, CY20 and XN979 showed more drought tolerance than other wheat cultivars in terms of drought susceptibility indexes

Statistical Analysis of Leaf Water Use Efficiency and Physiology Traits of Winter Wheat Under Drought Condition

Five statistical methods including simple correlation, multiple linear regression, stepwise regression, principal components, and path analysis were used to explore the relationship between leaf water use efficiency (WUE) and physiological traits (photosynthesis rate, stomatal conductance, transpiration rate, intercellular CO2 concentration, etc.) of 29 wheat cultivars. The results showed that photosynthesis rate, stomatal conductance, and transpiration rate were the most important leaf WUE parameters under drought condition. Based on the results of statistical analyses, principal component analysis could be the most suitable method to ascertain the relationship between leaf WUE and relative physiological traits. It is reasonable to assume that high leaf WUE wheat could be obtained by selecting breeding materials with high photosynthesis rate, low transpiration rate, and stomatal conductance under dry area

Morphological, anatomical and physiological responses of Campylotropis polyantha (Franch.) Schindl. seedlings to progressive water stress

In this study we implemented a potted water supply experiment for 100 days by a completely random sole-factored design with five treatments: 100% (W(100)). 80% (W(80)), 60% (W(60)). 40% (W(40)) and 20% (W(20)) of water holding capacity (WHC), corresponding to the soil volumetric water content (SVWC) maintained at 38.8 +/- 0.3%, 31.6 +/- 1.7%, 25.6 +/- 1.3%, 16.5 +/- 0.7%, and 8.1 +/- 1.1%, respectively. The objective was to evaluate the ability of the 2-month-old Campylotropis polyantha (Franch.) Schindl. seedlings to tolerate drought and to explore the mechanism resisting drought. We monitored the growth process of seedling height and leaf number monthly and further investigated those changes in plant growth, dry mass accumulation and allocation, water-use efficiency (WUE), leaf functional traits, chlorophyll a fluorescence and pigment contents across the water deficit gradient. We found that the seedlings presented optimal growth, dry mass production, and physiological activity only at the W(100) and W(80) treatments and afterwards significantly decreased with progressive water deficit: the WUE was improved under moderate water stress (W(60) and W(40)) but reduced under severe stress (W(20)). The serious leaf shedding, growth stopping and seedling death under the W(20) condition revealed that the current-year shrub seedlings could not withstand severe drought. Water stress-induced decrease in total plant leaf area due to a combination of limited expansion of younger leaves and shedding of old leaves caused the leaf area ratio reduction under drought. The reduced mesophyll cell was a major anatomical response of leaves along the water stress gradient. The progressive water stress significantly damaged light harvesting complex and reduced photochemical processes and PSII activity. Our results clearly showed that the current-year shrub seedlings took the avoidance and tolerance mechanisms to withstand progressive drought stress and around 25.6% SVWC and around 12.3% SVWC separately are thresholds to limit the optimal growth and dry mass production and to last growing and surviving for the current-year shrub seedlings. (C) 2010 Elsevier B.V. All rights reserved

Efficiency of Repeated Phytoextraction of Cadmium and Zinc from an Agricultural Soil Contaminated with Sewage Sludge

Long-term application of sewage sludge resulted in soil cadmium (Cd) and zinc (Zn) contamination in a pot experiment conducted to phytoextract Cd/Zn repeatedly using Sedum plumbizincicola and Apium graceolens in monoculture or intercropping mode eight times. Shoot yields and soil physicochemical properties changed markedly with increasing number of remediation crops when the two plant species were intercropped compared with the unplanted control soil and the two monoculture treatments. Changes in soil microbial indices such as average well colour development, soil enzyme activity and soil microbial counts were also significantly affected by the growth of the remediation plants, especially intercropping with S. plumbizincicola and A. graveolens. The higher yields and amounts of Cd taken up indicated that intercropping of the hyperaccumulator and the vegetable species may be suitable for simultaneous agricultural production and soil remediation, with larger crop yields and higher phytoremediation efficiencies than under monoculture conditions.Long-term application of sewage sludge resulted in soil cadmium (Cd) and zinc (Zn) contamination in a pot experiment conducted to phytoextract Cd/Zn repeatedly using Sedum plumbizincicola and Apium graceolens in monoculture or intercropping mode eight times. Shoot yields and soil physicochemical properties changed markedly with increasing number of remediation crops when the two plant species were intercropped compared with the unplanted control soil and the two monoculture treatments. Changes in soil microbial indices such as average well colour development, soil enzyme activity and soil microbial counts were also significantly affected by the growth of the remediation plants, especially intercropping with S. plumbizincicola and A. graveolens. The higher yields and amounts of Cd taken up indicated that intercropping of the hyperaccumulator and the vegetable species may be suitable for simultaneous agricultural production and soil remediation, with larger crop yields and higher phytoremediation efficiencies than under monoculture conditions

Phosphor-free nanopyramid white light-emitting diodes grown on {10(1)over-bar1} planes using nanospherical-lens photolithography

We reported a high-efficiency and low-cost nano-pattern method, the nanospherical-lens photolithography technique, to fabricate a SiO2 mask for selective area growth. By controlling the selective growth, we got a highly ordered hexagonal nanopyramid light emitting diodes with InGaN/GaN quantum wells grown on nanofacets, demonstrating an electrically driven phosphor-free white light emission. We found that both the quantum well width and indium incorporation increased linearly along the {10 (1) over bar1} planes towards the substrate and the perpendicular direction to the {10 (1) over bar1} planes as well. Such spatial distribution was responsible for the broadband emission. Moreover, using cathodoluminescence techniques, it was found that the blue emission originated from nanopyramid top, resembling the quantum dots, green emission from the InGaN quantum wells layer at the middle of sidewalls, and yellow emission mainly from the bottom of nanopyramid ridges, similar to the quantum wires.We reported a high-efficiency and low-cost nano-pattern method, the nanospherical-lens photolithography technique, to fabricate a SiO2 mask for selective area growth. By controlling the selective growth, we got a highly ordered hexagonal nanopyramid light emitting diodes with InGaN/GaN quantum wells grown on nanofacets, demonstrating an electrically driven phosphor-free white light emission. We found that both the quantum well width and indium incorporation increased linearly along the {10 (1) over bar1} planes towards the substrate and the perpendicular direction to the {10 (1) over bar1} planes as well. Such spatial distribution was responsible for the broadband emission. Moreover, using cathodoluminescence techniques, it was found that the blue emission originated from nanopyramid top, resembling the quantum dots, green emission from the InGaN quantum wells layer at the middle of sidewalls, and yellow emission mainly from the bottom of nanopyramid ridges, similar to the quantum wires. (C) 2013 AIP Publishing LLC

Application of large-scale integrated vertical-flow constructed wetland in Beijing Olympic forest park: design, operation and performance

This paper deals with the design, purification performance and public questionnaire of the integrated vertical-flow constructed wetland (IVCW) system built in Beijing Olympic Forest Park (BOFP). This IVCW system of 45 000 m2 has been operated to treat reclaimed wastewater and circulated lake water from Aohai lake. The first 6-month monitoring results in 2008 indicated that IVCW showed a statistically significant removal of TP and OP from reclaimed water and the removal of BOD5 from circulated lake water from Aohai lake. The questionnaire of Willingness To Pay (WTP) by visitors to the BOFP showed that 98.1% of the respondents were in favour of the construction of the wetland and approved the performance of IVCW. More importantly, during the periods of Beijing 2008 Olympic Games and Paralympic Games, the IVCW system helped to provide amenable surroundings for sight-seeing athletes and audiences, as well as tourists. The IVCW also helped to embody the concept of Harmony Between Human and Nature, a theme of the Olympics Games. Using IVCW for treating the reclaimed wastewater as recharge provides an innovative, affordable and practical way for northern China to treat municipal wastewaters.This paper deals with the design, purification performance and public questionnaire of the integrated vertical-flow constructed wetland (IVCW) system built in Beijing Olympic Forest Park (BOFP). This IVCW system of 45 000 m2 has been operated to treat reclaimed wastewater and circulated lake water from Aohai lake. The first 6-month monitoring results in 2008 indicated that IVCW showed a statistically significant removal of TP and OP from reclaimed water and the removal of BOD5 from circulated lake water from Aohai lake. The questionnaire of Willingness To Pay (WTP) by visitors to the BOFP showed that 98.1% of the respondents were in favour of the construction of the wetland and approved the performance of IVCW. More importantly, during the periods of Beijing 2008 Olympic Games and Paralympic Games, the IVCW system helped to provide amenable surroundings for sight-seeing athletes and audiences, as well as tourists. The IVCW also helped to embody the concept of Harmony Between Human and Nature, a theme of the Olympics Games. Using IVCW for treating the reclaimed wastewater as recharge provides an innovative, affordable and practical way for northern China to treat municipal wastewaters