Formation, development and degeneration of Tamarix taklamakanensis M.T. Liu community may be affected by wind-sand disturbance. On the basis of field survey and experiments that took eight years from 1994, it was foun...Formation, development and degeneration of Tamarix taklamakanensis M.T. Liu community may be affected by wind-sand disturbance. On the basis of field survey and experiments that took eight years from 1994, it was found that the plant community was formed in wet and low-lying land, developed in sand burying land, and died out in the land with strong wind erosion and severe sand burying. In the initial stage of the community formation, the low-lying land that was formed by wind erosion provided a suitable habitat for seed germination and plant rooting, but salt stress from ground water reduced seedling survival rate. In the developing stage of the community, sand burying stimulated vigorous growth of the shrubs. In the degenerative stage of the community, the wind erosion and sand burying resulted in dying out of the shrubs. It is therefore concluded that wind-sand disturbance has a positive role in the formation and development of the community, and is in a close association with the process of the community degeneration. Taking the habitat of T taklamakanensis into account, it may be appropriate to note that, under the conditions of frequent disturbance and severe stress, desert pioneer species are adaptable and able to survive. This might be a supplement to the CSR strategy.展开更多
Biofilm formation, one of the primary causes of biofouling, results in reduced membrane flux or increased transmembrane pressure and thus represents a major impediment to the wider implementation of membrane bioreact...Biofilm formation, one of the primary causes of biofouling, results in reduced membrane flux or increased transmembrane pressure and thus represents a major impediment to the wider implementation of membrane bioreactor （MBR） technologies for water purification. Most studies have focused on the role of bacteria in membrane fouling as they are the most dominant and best studied organisms present in the MBR. In contrast, there is limited information on the role of the archaeal community in biofilm formation in MBRs. This study investigated the composition of the archaeal community during the process of biofouling in an MBR. The archaeal community was observed to have lower richness and diversity in the biofilm than the sludge during the establishment ofbiofilms at low transmembrane pressure （TMP）. Clustering of the communities based on the Bray-Curtis similarity matrix indicated that a subset of the sludge archaeal community formed the initial biofilms. The archaeal community in the biofilm was mainly composed of Thermoprotei, Thermoplasmata, Thermococci, Methanopyri, Methanomicrobia and Halobacteria. Among them, the Thermoprotei and Thermoplasmata were present at higher relative proportions in the biofilms than they were in the sludge. Additionally, the Thermoprotei, Thermoplasmata and Thermococci were the dominant organisms detected in the initial biofilms at low TMP, while as the TMP increased, the Methanopyri, Methanomicrobia, Aciduliprofundum and Halobacteria were present at higher abundances in the biofilms at high TMP.展开更多
In 2011, the Occupy Wall Street movement made history as one of the largest grassroots protest events in the United States. Members made frequent use of social media tools, like Twitter, to share information and mobil...In 2011, the Occupy Wall Street movement made history as one of the largest grassroots protest events in the United States. Members made frequent use of social media tools, like Twitter, to share information and mobilize participants. This study uses content analysis to examine the way that Twitter is used to incite, organize, and perpetuate protest movements. 1500 tweets in total were coded for content and linguistic features to provide insight into how Twitter is used to achieve different goals surrounding protest movements, the tonality of the tweets, and the purpose of distributed messages. Our findings indicate that Twitter is a tool primarily used for sharing objective, logistical information, along with opinions, to create a unified community and mobilize individuals to participate in a physical space of protest.展开更多
文摘Formation, development and degeneration of Tamarix taklamakanensis M.T. Liu community may be affected by wind-sand disturbance. On the basis of field survey and experiments that took eight years from 1994, it was found that the plant community was formed in wet and low-lying land, developed in sand burying land, and died out in the land with strong wind erosion and severe sand burying. In the initial stage of the community formation, the low-lying land that was formed by wind erosion provided a suitable habitat for seed germination and plant rooting, but salt stress from ground water reduced seedling survival rate. In the developing stage of the community, sand burying stimulated vigorous growth of the shrubs. In the degenerative stage of the community, the wind erosion and sand burying resulted in dying out of the shrubs. It is therefore concluded that wind-sand disturbance has a positive role in the formation and development of the community, and is in a close association with the process of the community degeneration. Taking the habitat of T taklamakanensis into account, it may be appropriate to note that, under the conditions of frequent disturbance and severe stress, desert pioneer species are adaptable and able to survive. This might be a supplement to the CSR strategy.
基金supported by a research grant (MEWRC651/ 06/177) from the Environment and Water Industry Programme Office of Singapore
文摘Biofilm formation, one of the primary causes of biofouling, results in reduced membrane flux or increased transmembrane pressure and thus represents a major impediment to the wider implementation of membrane bioreactor （MBR） technologies for water purification. Most studies have focused on the role of bacteria in membrane fouling as they are the most dominant and best studied organisms present in the MBR. In contrast, there is limited information on the role of the archaeal community in biofilm formation in MBRs. This study investigated the composition of the archaeal community during the process of biofouling in an MBR. The archaeal community was observed to have lower richness and diversity in the biofilm than the sludge during the establishment ofbiofilms at low transmembrane pressure （TMP）. Clustering of the communities based on the Bray-Curtis similarity matrix indicated that a subset of the sludge archaeal community formed the initial biofilms. The archaeal community in the biofilm was mainly composed of Thermoprotei, Thermoplasmata, Thermococci, Methanopyri, Methanomicrobia and Halobacteria. Among them, the Thermoprotei and Thermoplasmata were present at higher relative proportions in the biofilms than they were in the sludge. Additionally, the Thermoprotei, Thermoplasmata and Thermococci were the dominant organisms detected in the initial biofilms at low TMP, while as the TMP increased, the Methanopyri, Methanomicrobia, Aciduliprofundum and Halobacteria were present at higher abundances in the biofilms at high TMP.
文摘In 2011, the Occupy Wall Street movement made history as one of the largest grassroots protest events in the United States. Members made frequent use of social media tools, like Twitter, to share information and mobilize participants. This study uses content analysis to examine the way that Twitter is used to incite, organize, and perpetuate protest movements. 1500 tweets in total were coded for content and linguistic features to provide insight into how Twitter is used to achieve different goals surrounding protest movements, the tonality of the tweets, and the purpose of distributed messages. Our findings indicate that Twitter is a tool primarily used for sharing objective, logistical information, along with opinions, to create a unified community and mobilize individuals to participate in a physical space of protest.
