Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis tha...Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis thaliana (L.) Heynh. by using cDNA an-ay and found that stress responsive genes, such as,Arabidopsis homolog of MEK kinase 1 (ATMEKK1), ReL/SpoT homolog 3 ( At-RSH3), Catalase 1 ( Cat1) and Ferritin 1 (Fer1), were down-regulated by auxin, indicating that auxin regulates ale expression of stress responsive genes. We also demonstrated that nitrilase genes, nitrilase I ( NIT]) and nitrilase 2 (NIT2) involving in indole-3-acetic acid (IAA) biosynthesis, were induced by salinity stress, suggesting that the level of IAA might increase in response to salinity stress. To dissect the signal pathway involved in the interaction, two auxin insensitive mutants, auxin resistant 2 (axr2) and auxin resistant 1-3 (axrl-3) were used. Stress responsive genes were induced by salt stress in wild type and axr2, but not in axr1-3. The result suggests that die interaction between auxin and stress responses may be linked in the ubiquitin pathway.展开更多
This paper presents a detailed study on the textural and geochemical characteristics of the proglacial sediments near the edge of modern Nelson Ice Cap, Antarctica. The grain size distributions of the proglacial sedim...This paper presents a detailed study on the textural and geochemical characteristics of the proglacial sediments near the edge of modern Nelson Ice Cap, Antarctica. The grain size distributions of the proglacial sediments are characteristic of glacigenic deposits, but very different from those of aeolian and lacustrine sediments. Moreover, the grain size distributions of the proglacial sediments are fractal with a dimension of about 2.9, and the fractal dimensions can be used as another summary statistical parameter for quantifying the relative amounts of coarse and fine materials. Correlations between the absolute element abundances of the proglacial sediments are very weak due to mineral partitioning and other effects of glacial processes, but correlations between the element/Rb ratios are statistically significant. This finding indicates that element/Rb ratios can be used to reduce or eliminate the effects of glacial processes, evaluate geochemical data and determine the sediment provenance in the foreland of Antarctic glacier. Comparisons on the element concentrations among different environments suggest that the proglacial sediments are derived predominantly from local bedrocks and appear to be natural in origin. Thus these natural sediments can be used to study chemical weathering in the proglacial foreland of modern glacier.展开更多
The decomposition of plant litter is a key process of litter decomposition to global climate warming in plateau in the flows of energy and nutrients in ecosystems. However, the response wetlands remains largely unknow...The decomposition of plant litter is a key process of litter decomposition to global climate warming in plateau in the flows of energy and nutrients in ecosystems. However, the response wetlands remains largely unknown. In this study, we conducted a one-year litter decomposition experiment along an elevation gradient from 1891 m to 3260 m on the Yurman Plateau of Southwest China, using different litter types to determine the influences of climate change, litter quality and microenvironment on the decomposition rate. The results showed that the average decomposition rate (K) increased from 0.608 to 1.152, and the temperature sensitivity of litter mass losses was approximately 4.98%/℃ along the declining elevation gradient. Based on a correlation analysis, N concentrations and C : N ratios in the litter were the best predictors of the decomposition rate, with significantly positive and negative correlations, respectively. Additionally, the cumulative effects of decomposition were clearly observed in the mixtures of Scirpus tabernaemontani and Zizania caduciflora. Moreover, the litter decomposition rate in the water was higher than that in the sediment, especially in high-elevation areas where the microenvironment was significantly affected by temperature. These results suggest that future climate warming will have significant impacts on plateau wetlands, which have important fimctions in biogeochemical cycling in cold highland ecosystems.展开更多
A whole year analysis of riverine dissolved organic carbon (DOC) concentrations in the Xijiang River (XJR), South China, showed that the mean riverine DOC concentration (1.24 mg L-1) in the XJR was notably lower than ...A whole year analysis of riverine dissolved organic carbon (DOC) concentrations in the Xijiang River (XJR), South China, showed that the mean riverine DOC concentration (1.24 mg L-1) in the XJR was notably lower than the averaged value (5.75 mg L-1) of the global riverine DOC concentration in several major rivers. There is an inconspicuous monthly fluctuation of the DOC signal in the XJR, but on a semi-yearly time scale, however, the riverine DOC concentration had significant difference between hydrological seasons. The DOC level during the flood season (1.18 mg L-1) was less than that during the non-flood season (1.40 mg L-1). Owing to the concomitance of the flushing and dilution effects of the runoff during the high-water period, the variation of riverine DOC concentration with discharge in the XJR differed from that reported in many other major rivers. The DOC export flux above the city of Wuzhou was about 0.62× 106 g C km-2 yr-1. The DOC transported during the "056" Massive Flood period comprised 30.35% of the annual total, while the discharge accounted for 36.32% of the total annual flow. The characteristics in riverine DOC concentration in the XJR were attributed to the combined effect of the geomorphologic, monsoon climatic and hydrological processes as well as land-use within the drainage basin.展开更多
Arsenic (As) in the soils of South-Eastern Bangladesh is not rely a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a...Arsenic (As) in the soils of South-Eastern Bangladesh is not rely a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a promising fast growing tree species in Bangladesh which has dso a potential to be planted in arsenic contaminated areas. This study tssessed the role of arbuscular mycorrhizal (AM) fungi on the growth of 7. arborea in arsenic amended soils at nursery stage. Before sowing ;eeds, soils were treated with four different concentrations (10 mg.kg^-1, 25 mg.kg^-1, 50 mg.kg^-1, and 100 mg.kg^-1) of Arsenic. Growth parameters length of shoot and root, collar diameter, fresh and dry weight of shoot and root) of the plant, and mycorrhizal root colonization and spore population in the rhizosphere soil of G. arborea were recorded. Mycorrhizal seedlings showed better growth than non-mycorrhizal eedlings. Myeorrhizal seedlings planted in soil with 10-mg.kg^-1 arsenic howed best performance in terms of growth, biomass and mycorrhizal :olonization, compared to other treatments with higher concentration of Lrsenie. With increasing arsenic concentration, growth of seedlings, nycorrhizal infection rate and spore population, all decreased ignificantly (p〈0.05). The mycorrhizal seedlings had as much as 40% higher increment in total growth and 2.4 times higher increment in biomass compared to non-mycorrhizal seedlings. The study clearly indicated that mycorrhizal inoculation could reduce the harmful effects of arsenic on the initial growth of G. arborea Linn. in degraded soil at nursery stage.展开更多
Mangrove-derived dissolved organic matter (DOM) has an important effect on estuarine and coastal area on a large scale. In order to improve the understanding of origin, composition, and fate of DOM in mangrove-fring...Mangrove-derived dissolved organic matter (DOM) has an important effect on estuarine and coastal area on a large scale. In order to improve the understanding of origin, composition, and fate of DOM in mangrove-fringed estuarine and coastal areas, dissolved humic substances (DHS) were isolated from one mangrove pore-water sample and one near-shore seawater sample downstream the mangrove pore-water site in the eastern coast of Hainan Island, South China. Fulvic acids, humic acids and XAD-4 fractions were obtained from the two water samples by using a two-column array of XAD-g and XAD-4 resins. Chemica~ and spectroscopic methods were used to analyze the features of these DHS. Compared to the mangrove pore-water DHS, the near-shore seawater DHS were found rich in 13C with lower C/N ratios and more aliphatic compounds and carbohydrates, but less aromatic structures and carboxyl groups. As for the three fractions of the two DHS, XAD-4 fractions contain more aliphatics, carbohydrates, carboxyl groups, and enrich in 13C with respect to both fulvic and humic acids. Photo-oxidation transformation and contribution from marine-derived DOM were considered as the main reasons resulted in the difference in compositional features for these DHS in this study.展开更多
Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic s...Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic soils located at the Mangshan Mountains, Hunan Province, China. Many evidences showed that separate pyrophosphate extracted mainly KCI-extractable Al, organo-Al complexes and some inorganic Al compounds, whereas separate CuCl2 extracted KCl-extractable Al and some organo-Al complexes. CuCl2 extracted much less amounts of Al than pyrophosphate did from the soils. Separate oxalate did not extract all KCl-Pyrophosphate- CuCl2 -oxalate sequentially extractable Al and Fe. Also, separate DCB did not extract all KCl- pyrophosphate- CuCl2 -oxalate- DCB sequentially extractable Al. The forms of Al extracted by oxalate and DCB from the soils were majorly noncrystalline. The interlayered materials of 1.4-nm intergrade minerals of the soils were attributed mainly to hydroxy Al polymers.展开更多
Based on field observations carried out in August, 2008, we obtained a set of data on velocity, hydrography, and hydroehemistry in the Luzon Strait, with which the velocity structure of the area, especially in deep ch...Based on field observations carried out in August, 2008, we obtained a set of data on velocity, hydrography, and hydroehemistry in the Luzon Strait, with which the velocity structure of the area, especially in deep channels, was analyzed, and the material fluxes, including water, dissolved oxygen, and nutrients were calculated. The results indicate that a net eastward water flux of 7.0 Sv occurred through the Luzon Strait. The deep layer flux in the southern part, through the deep channel, was westward with a value of 1.9 Sv, which confirms that deep Pacific water flows into the South China Sea via the deep passage in the Luzon Strait. Accordingly, the net flux of dissolved oxygen was 13.2× 10 5 mol/s, and the values for dissolved inorganic nitrogen, phosphate and silicate were 4.6× 10 4 mol/s, 2.4× 10 3 mol/s, and 8.9×10 4 mol/s, respectively. Detailed descriptions of these material fluxes in the upper layer, the upper-intermediate layer, the lower-intermediate layer, and the deep layer through the Luzon Strait are discussed. These results and interpretations highlight the importance of material exchanges between the South China Sea and the Pacific Ocean.展开更多
Observation data from a cruise in the Nansha Islands, in May to June 1990, December, 1993, September to October 1994, and July, 1999, respectively, were used to develop the method presented here to indicate the existi...Observation data from a cruise in the Nansha Islands, in May to June 1990, December, 1993, September to October 1994, and July, 1999, respectively, were used to develop the method presented here to indicate the existing strength of the dissolved oxygen maximum in the vertical distribution of Nansha Islands waters. Its seasonal variation and regional distribution are discussed in this paper. Analysis results showed that the distribution of the strength of dissolved oxygen maximum (DO max -DO sur ) was closely related to the upper layer circulation and the bioactivity of Nansha Islands seawater.展开更多
Ionic partition equilibrium in charged membrane immersed in solution of single electrolyte with monovalence or multi-valence is systematically investigated and several expressions are established for determination of ...Ionic partition equilibrium in charged membrane immersed in solution of single electrolyte with monovalence or multi-valence is systematically investigated and several expressions are established for determination of partition coefficients. On this basis, the effects of the ratio of membrane charge density to bulk electrolyte solution concentration, the charge sign and valence of electrolyte ions and the type of membrane on the partition equilibrium were analyzed and simulated within chosen parameters. It is revealed that ion partition is not related solely with the respective concentrations but also definitely with the concentration ratio of fixed group to bulk solution in addition to the charge sign and the valence. For a counterion, the partition coefficient increases with this ratio and the valence; while for a coion, the partition coefficient decreases with this ratio and the valence. The theoretical calculations were compared with the experimental data and a good agreement was observed.展开更多
An 8-week growth trial was conducted to determine dietary arginine requirement for juvenile Pacific white shrimp Litopenaeus vannamei (Boone) with an initial average body weight of 0.47 g reared in low-salinity wat...An 8-week growth trial was conducted to determine dietary arginine requirement for juvenile Pacific white shrimp Litopenaeus vannamei (Boone) with an initial average body weight of 0.47 g reared in low-salinity water (0.50-1.50 g L-1). Six isonitrogenous and isoenergetic semipurified diets (crude protein 360 g/kg and gross energy 19.70 kJ/g) were formulated with fish meal and wheat gluten as the intact protein source.展开更多
In recent years, an impressive research literature of relevance to business education has accumulated from several diverse areas of study to show that without the acquisition of what have come to be called "soft ski...In recent years, an impressive research literature of relevance to business education has accumulated from several diverse areas of study to show that without the acquisition of what have come to be called "soft skills", the level of potential success in the context of business transactions, production, and international trade cannot be maximised. To be clear, soft skills refer to an array of personal skills such as the capacity to communicate, and problem-solve, possess leadership qualities, and the ability to work well in a team, be amicable, and a good listener. Indeed, there are some studies to which the authors will allude that reveal that "soft skills" are in fact more important to success in business than competencies of"hard skills" or the technological production skills upon which business itself must also depend. The central objective of this paper is to exhibit the relevance of this new understanding of the integral role played by soft skills in business success, and thus to the economic growth enjoyed by a country. What the authors say about the particular pertinence which the research on soft skills has for Vietnam is likely to be equally important to improving success in business for other developing countries.展开更多
In this paper, using focal mechanism solutions of moderate-strong earthquakes in Yunnan and its adjacent areas, and based on the statistical analysis of the parameters of focal mechanism solutions, we discussed in det...In this paper, using focal mechanism solutions of moderate-strong earthquakes in Yunnan and its adjacent areas, and based on the statistical analysis of the parameters of focal mechanism solutions, we discussed in detail the earthquake fault types and the characteristics of the modern tectonic stress field in the Yunnan region. The results show that most moderate-strong earthquakes occurring in the Yunnan region are of the strike-slip type, amounting to 80% of the total. Normal faulting and normal with strike-slip and reverse and reverse with strike-slip earthquakes is almost equivalent in proportion, about 8% each. The tectonic stress field of the Yunnan region is near-horizontal, and the dips of earthquake fault planes are large. There are three main dynamic sources acting on the Yunnan region: one is the NE, NNE and NNW-directed acting force from Myanmar, Laos and Vietnam; the second is the SE-SSE directed force from the Sichuan and Sichuan-Yunnan rhombus block and the third is the NW-NNW directed force from the South China block. These three acting forces have controlled the faulting behavior of the main faults and the characteristics of strong earthquake activity of Yunnan and its adjacent regions.展开更多
Bamboos are one of the fast-growing and multiple use species in the world, and thus bamboo forests/plantations play an important role in C sequestration at regional and global levels. We studied aboveground litterfall...Bamboos are one of the fast-growing and multiple use species in the world, and thus bamboo forests/plantations play an important role in C sequestration at regional and global levels. We studied aboveground litterfall, litter decomposition and nutrient dynamics for two years in two subtropical bamboo ecosystems in Southwest China so as to test the hypothesis that litter quality determine the rate and nutrient dynamics during decomposition of different litter fractions. Mean annual total aboveground litter production ranged from 494 to 434 g m-2 in two bamboo stands (P stand, dominated by Pleioblastus amarus and H stand, hybrid bamboo dominated by Bambusa pervariabilis x Dendrocalamopsis daii). Bulk (-80%) of litter production was contributed by leaf litter in two stands followed by twigs and sheathes. Different litter fractions represented considerable variations in the rates of mass loss and nutrient release. Variation of the mass remaining after 2 years of decomposition was significantly explained by initial C/N ratio and initial P concentration. Initial concentrations of N, P, Ca, and Mg explained 57.9%, 95.0%, 99.8% and 98.1%, respectively, of the variations of these elements mass remaining after 2 years of decomposition. The patterns of nutrient dynamics and the final amount remaining were mainly determined by their initial litter substrate quality in tl^ese two subtropical bamboo plantations.展开更多
This year marks the 100 th anniversary of Nelson Mandela's birth.The reason the global media reacted strongly to the news of Mandela's death five years ago can be found in his lasting contributions and his immortal ...This year marks the 100 th anniversary of Nelson Mandela's birth.The reason the global media reacted strongly to the news of Mandela's death five years ago can be found in his lasting contributions and his immortal spirit.Mandela's spirit is characterized by the noble ideals of opposing apartheid and achieving democracy,freedom and equality;by his philosophy of reconciliation,marked by magnanimity and forgiveness;by his principled stand for peace and justice in Africa and the world;by his political wisdom in summing up the situation and meeting the challenges of the times,evinced in his quitting office at the peak of his political life;by his thankfulness for help and concern for vulnerable groups;and by his personal charm,as reflected in his magnanimity,sense of humor,sincerity and sense of equality.These six qualities are closely connected and constitute a dialectical unity.South Africa is the birthplace of Mandela and the soil in which the Mandela spirit grew.The fact that South Africa produced a Mandela is closely connected with his historical era and the social environment,as well as the influence of countries around the world and the international support he received.Above all,however,Mandela's rise was closely tied to his noble ideals and outstanding character.In a word,the internal and external origins ofthe Mandela spirit complement and illuminate each other.The Mandela spirit is rooted in South Africa,yet it belongs to the whole world and the whole human race.Its radiant reason,dynamism and strong personal influence will continue to illuminate our world with an eternal charisma.The world of today needs the Mandela spirit more than ever.展开更多
Owing to global warming,frequent ice shelf disintegration and rapid acceleration of inland ice flow have occurred in recent decades,which impacts the Antarctic mass balance and the global sea level[1].These events are...Owing to global warming,frequent ice shelf disintegration and rapid acceleration of inland ice flow have occurred in recent decades,which impacts the Antarctic mass balance and the global sea level[1].These events are closely linked to atmospheric and oceanic processes.The prolonged melt season and larger extent of melt ponds on the ice shelf surface[2],as well as enhanced basal melting caused by warmer sea water[3],will induce crevasses that展开更多
The newly developed CRISPR(Clustered Regularly Interspaced Short Palindromic Repeats)/Cas(CRISPR-associated) system has emerged as an efficient tool for genome-editing, providing an alternative to classical mutagenesi...The newly developed CRISPR(Clustered Regularly Interspaced Short Palindromic Repeats)/Cas(CRISPR-associated) system has emerged as an efficient tool for genome-editing, providing an alternative to classical mutagenesis and transgenic methods to study gene function and improve crop traits. CRISPR/Cas facilitates targeted gene editing through RNA-guided DNA cleavage followed by cellular DNA repair mechanisms that introduce sequence changes at the site of cleavage. Here we describe a detailed procedure for our previously developed and highly efficient CRISPR/Cas9 method that allows the generation of heritable-targeted gene mutations andcorrections in Arabidopsis. This protocol describes the strategies and steps for the selection of targets, design of single-guide RNA(sg RNA), vector construction and analysis of transgenic lines. We also offer a method to target two loci simultaneously using vectors containing two different sg RNAs. The principles described in this protocol can be applied to other plant species to generate stably inherited DNA modifications.展开更多
This essay examines the Daoist metaphysical masters' hermeneutic misreading of the Confucian classics during the Wei and Jin Dynasties. Applying the concept of misreading as the theoretical guideline, we will first a...This essay examines the Daoist metaphysical masters' hermeneutic misreading of the Confucian classics during the Wei and Jin Dynasties. Applying the concept of misreading as the theoretical guideline, we will first analyze the three important supporting columns of Confucian literary theory: the importance of virtue/morality, the authority of literary sages and the ontology of the classics, and then we will examine the metaphysical masters' subversion of the Confucian classics by misreading with their Daoist literary theory and concepts. In their hermeneutic misreading of the Confucian classics, the metaphysical masters in fact fused the original concepts of the Confucian classics with their contemporary Daoist hermeneutics, and the result of such a fusion is that the original meanings as the signified parted from the signifiers--the texts of the classics themselves--and were turned into repositories of contemporary Daoist meanings. In such a hermeneutic misreading, the Daoist theorists forced the Confucian theory and its ontology to gloomily withdraw from the cultural center, and gradually took the spotlight on the historical stage of the Wei and Jin Dynasties. In their open attitudes and flexible system, the metaphysical theorists constructed an age of enlightenment for the development of literary theory. With their hermeneutic misreading, the metaphys- ical literary theorists indeed broke through the world of Confucianism, won the right of expression, and voluntarily moved toward the self-fulfillment of their own system in the Wei and Jin Dynasties.展开更多
文摘Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis thaliana (L.) Heynh. by using cDNA an-ay and found that stress responsive genes, such as,Arabidopsis homolog of MEK kinase 1 (ATMEKK1), ReL/SpoT homolog 3 ( At-RSH3), Catalase 1 ( Cat1) and Ferritin 1 (Fer1), were down-regulated by auxin, indicating that auxin regulates ale expression of stress responsive genes. We also demonstrated that nitrilase genes, nitrilase I ( NIT]) and nitrilase 2 (NIT2) involving in indole-3-acetic acid (IAA) biosynthesis, were induced by salinity stress, suggesting that the level of IAA might increase in response to salinity stress. To dissect the signal pathway involved in the interaction, two auxin insensitive mutants, auxin resistant 2 (axr2) and auxin resistant 1-3 (axrl-3) were used. Stress responsive genes were induced by salt stress in wild type and axr2, but not in axr1-3. The result suggests that die interaction between auxin and stress responses may be linked in the ubiquitin pathway.
基金The work was supported by the Nationa1 Natural ScienceFoundation of China(Grant No.40231002 and 40076032)the project of Chinese Academy of Sciences(Grant No.KZCX2-303)
文摘This paper presents a detailed study on the textural and geochemical characteristics of the proglacial sediments near the edge of modern Nelson Ice Cap, Antarctica. The grain size distributions of the proglacial sediments are characteristic of glacigenic deposits, but very different from those of aeolian and lacustrine sediments. Moreover, the grain size distributions of the proglacial sediments are fractal with a dimension of about 2.9, and the fractal dimensions can be used as another summary statistical parameter for quantifying the relative amounts of coarse and fine materials. Correlations between the absolute element abundances of the proglacial sediments are very weak due to mineral partitioning and other effects of glacial processes, but correlations between the element/Rb ratios are statistically significant. This finding indicates that element/Rb ratios can be used to reduce or eliminate the effects of glacial processes, evaluate geochemical data and determine the sediment provenance in the foreland of Antarctic glacier. Comparisons on the element concentrations among different environments suggest that the proglacial sediments are derived predominantly from local bedrocks and appear to be natural in origin. Thus these natural sediments can be used to study chemical weathering in the proglacial foreland of modern glacier.
基金Under the auspices of Special Projects of National Key Basic Research Program of China(No.2012CB426509)National Natural Science Foundation of China(No.40971285,31370497,31500409)Yunnan Innovation Talents of Science and Technology Plan of China(No.2012HC007)
文摘The decomposition of plant litter is a key process of litter decomposition to global climate warming in plateau in the flows of energy and nutrients in ecosystems. However, the response wetlands remains largely unknown. In this study, we conducted a one-year litter decomposition experiment along an elevation gradient from 1891 m to 3260 m on the Yurman Plateau of Southwest China, using different litter types to determine the influences of climate change, litter quality and microenvironment on the decomposition rate. The results showed that the average decomposition rate (K) increased from 0.608 to 1.152, and the temperature sensitivity of litter mass losses was approximately 4.98%/℃ along the declining elevation gradient. Based on a correlation analysis, N concentrations and C : N ratios in the litter were the best predictors of the decomposition rate, with significantly positive and negative correlations, respectively. Additionally, the cumulative effects of decomposition were clearly observed in the mixtures of Scirpus tabernaemontani and Zizania caduciflora. Moreover, the litter decomposition rate in the water was higher than that in the sediment, especially in high-elevation areas where the microenvironment was significantly affected by temperature. These results suggest that future climate warming will have significant impacts on plateau wetlands, which have important fimctions in biogeochemical cycling in cold highland ecosystems.
基金supported by the Natural Science Foundation of China (Grant Nos. 40871143 and 41071054)funds of China Geological Survey (karst[2011] Geo-surveying 01-01-23)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Guangdong Provincial Natural Science Foundation of China (Grant No. 7003669)
文摘A whole year analysis of riverine dissolved organic carbon (DOC) concentrations in the Xijiang River (XJR), South China, showed that the mean riverine DOC concentration (1.24 mg L-1) in the XJR was notably lower than the averaged value (5.75 mg L-1) of the global riverine DOC concentration in several major rivers. There is an inconspicuous monthly fluctuation of the DOC signal in the XJR, but on a semi-yearly time scale, however, the riverine DOC concentration had significant difference between hydrological seasons. The DOC level during the flood season (1.18 mg L-1) was less than that during the non-flood season (1.40 mg L-1). Owing to the concomitance of the flushing and dilution effects of the runoff during the high-water period, the variation of riverine DOC concentration with discharge in the XJR differed from that reported in many other major rivers. The DOC export flux above the city of Wuzhou was about 0.62× 106 g C km-2 yr-1. The DOC transported during the "056" Massive Flood period comprised 30.35% of the annual total, while the discharge accounted for 36.32% of the total annual flow. The characteristics in riverine DOC concentration in the XJR were attributed to the combined effect of the geomorphologic, monsoon climatic and hydrological processes as well as land-use within the drainage basin.
文摘Arsenic (As) in the soils of South-Eastern Bangladesh is not rely a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a promising fast growing tree species in Bangladesh which has dso a potential to be planted in arsenic contaminated areas. This study tssessed the role of arbuscular mycorrhizal (AM) fungi on the growth of 7. arborea in arsenic amended soils at nursery stage. Before sowing ;eeds, soils were treated with four different concentrations (10 mg.kg^-1, 25 mg.kg^-1, 50 mg.kg^-1, and 100 mg.kg^-1) of Arsenic. Growth parameters length of shoot and root, collar diameter, fresh and dry weight of shoot and root) of the plant, and mycorrhizal root colonization and spore population in the rhizosphere soil of G. arborea were recorded. Mycorrhizal seedlings showed better growth than non-mycorrhizal eedlings. Myeorrhizal seedlings planted in soil with 10-mg.kg^-1 arsenic howed best performance in terms of growth, biomass and mycorrhizal :olonization, compared to other treatments with higher concentration of Lrsenie. With increasing arsenic concentration, growth of seedlings, nycorrhizal infection rate and spore population, all decreased ignificantly (p〈0.05). The mycorrhizal seedlings had as much as 40% higher increment in total growth and 2.4 times higher increment in biomass compared to non-mycorrhizal seedlings. The study clearly indicated that mycorrhizal inoculation could reduce the harmful effects of arsenic on the initial growth of G. arborea Linn. in degraded soil at nursery stage.
基金Supported by the National Natural Science Foundation of China(Nos.40906041,41021064)the State Key Laboratory of Estuarine and Coastal Research (SKLEC) of East China Normal University(Nos.2012KYYW05,201202)
文摘Mangrove-derived dissolved organic matter (DOM) has an important effect on estuarine and coastal area on a large scale. In order to improve the understanding of origin, composition, and fate of DOM in mangrove-fringed estuarine and coastal areas, dissolved humic substances (DHS) were isolated from one mangrove pore-water sample and one near-shore seawater sample downstream the mangrove pore-water site in the eastern coast of Hainan Island, South China. Fulvic acids, humic acids and XAD-4 fractions were obtained from the two water samples by using a two-column array of XAD-g and XAD-4 resins. Chemica~ and spectroscopic methods were used to analyze the features of these DHS. Compared to the mangrove pore-water DHS, the near-shore seawater DHS were found rich in 13C with lower C/N ratios and more aliphatic compounds and carbohydrates, but less aromatic structures and carboxyl groups. As for the three fractions of the two DHS, XAD-4 fractions contain more aliphatics, carbohydrates, carboxyl groups, and enrich in 13C with respect to both fulvic and humic acids. Photo-oxidation transformation and contribution from marine-derived DOM were considered as the main reasons resulted in the difference in compositional features for these DHS in this study.
文摘Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic soils located at the Mangshan Mountains, Hunan Province, China. Many evidences showed that separate pyrophosphate extracted mainly KCI-extractable Al, organo-Al complexes and some inorganic Al compounds, whereas separate CuCl2 extracted KCl-extractable Al and some organo-Al complexes. CuCl2 extracted much less amounts of Al than pyrophosphate did from the soils. Separate oxalate did not extract all KCl-Pyrophosphate- CuCl2 -oxalate sequentially extractable Al and Fe. Also, separate DCB did not extract all KCl- pyrophosphate- CuCl2 -oxalate- DCB sequentially extractable Al. The forms of Al extracted by oxalate and DCB from the soils were majorly noncrystalline. The interlayered materials of 1.4-nm intergrade minerals of the soils were attributed mainly to hydroxy Al polymers.
基金Supported by National Natural Science Foundation of China (Nos.40906004,40776005 and 40890153)National High Technology Research and Development Program of China (863 Program) (2008AA09A402)Polar Science Foundation of China (20080206)
文摘Based on field observations carried out in August, 2008, we obtained a set of data on velocity, hydrography, and hydroehemistry in the Luzon Strait, with which the velocity structure of the area, especially in deep channels, was analyzed, and the material fluxes, including water, dissolved oxygen, and nutrients were calculated. The results indicate that a net eastward water flux of 7.0 Sv occurred through the Luzon Strait. The deep layer flux in the southern part, through the deep channel, was westward with a value of 1.9 Sv, which confirms that deep Pacific water flows into the South China Sea via the deep passage in the Luzon Strait. Accordingly, the net flux of dissolved oxygen was 13.2× 10 5 mol/s, and the values for dissolved inorganic nitrogen, phosphate and silicate were 4.6× 10 4 mol/s, 2.4× 10 3 mol/s, and 8.9×10 4 mol/s, respectively. Detailed descriptions of these material fluxes in the upper layer, the upper-intermediate layer, the lower-intermediate layer, and the deep layer through the Luzon Strait are discussed. These results and interpretations highlight the importance of material exchanges between the South China Sea and the Pacific Ocean.
文摘Observation data from a cruise in the Nansha Islands, in May to June 1990, December, 1993, September to October 1994, and July, 1999, respectively, were used to develop the method presented here to indicate the existing strength of the dissolved oxygen maximum in the vertical distribution of Nansha Islands waters. Its seasonal variation and regional distribution are discussed in this paper. Analysis results showed that the distribution of the strength of dissolved oxygen maximum (DO max -DO sur ) was closely related to the upper layer circulation and the bioactivity of Nansha Islands seawater.
基金Supported by the National Natural Science Foundation of China (No. 29976040), the Natural Science Foundation of Anhui Province(No. 99045431) and the Foundation of Environments and Resources of USTC (2000).
文摘Ionic partition equilibrium in charged membrane immersed in solution of single electrolyte with monovalence or multi-valence is systematically investigated and several expressions are established for determination of partition coefficients. On this basis, the effects of the ratio of membrane charge density to bulk electrolyte solution concentration, the charge sign and valence of electrolyte ions and the type of membrane on the partition equilibrium were analyzed and simulated within chosen parameters. It is revealed that ion partition is not related solely with the respective concentrations but also definitely with the concentration ratio of fixed group to bulk solution in addition to the charge sign and the valence. For a counterion, the partition coefficient increases with this ratio and the valence; while for a coion, the partition coefficient decreases with this ratio and the valence. The theoretical calculations were compared with the experimental data and a good agreement was observed.
文摘An 8-week growth trial was conducted to determine dietary arginine requirement for juvenile Pacific white shrimp Litopenaeus vannamei (Boone) with an initial average body weight of 0.47 g reared in low-salinity water (0.50-1.50 g L-1). Six isonitrogenous and isoenergetic semipurified diets (crude protein 360 g/kg and gross energy 19.70 kJ/g) were formulated with fish meal and wheat gluten as the intact protein source.
文摘In recent years, an impressive research literature of relevance to business education has accumulated from several diverse areas of study to show that without the acquisition of what have come to be called "soft skills", the level of potential success in the context of business transactions, production, and international trade cannot be maximised. To be clear, soft skills refer to an array of personal skills such as the capacity to communicate, and problem-solve, possess leadership qualities, and the ability to work well in a team, be amicable, and a good listener. Indeed, there are some studies to which the authors will allude that reveal that "soft skills" are in fact more important to success in business than competencies of"hard skills" or the technological production skills upon which business itself must also depend. The central objective of this paper is to exhibit the relevance of this new understanding of the integral role played by soft skills in business success, and thus to the economic growth enjoyed by a country. What the authors say about the particular pertinence which the research on soft skills has for Vietnam is likely to be equally important to improving success in business for other developing countries.
基金sponsored by the important projects of Yunnan Province,entitled"The regularity of strong earthquake activities and the plate margindynamic mechanism on the eastern margin of the Qinghai-Tibet plateau"(2010CC006)"Study on relationship between evolutionary dynamics of geophysical and geochemistry field and strong seismic activity in Yunnan"(JCYB200806015)
文摘In this paper, using focal mechanism solutions of moderate-strong earthquakes in Yunnan and its adjacent areas, and based on the statistical analysis of the parameters of focal mechanism solutions, we discussed in detail the earthquake fault types and the characteristics of the modern tectonic stress field in the Yunnan region. The results show that most moderate-strong earthquakes occurring in the Yunnan region are of the strike-slip type, amounting to 80% of the total. Normal faulting and normal with strike-slip and reverse and reverse with strike-slip earthquakes is almost equivalent in proportion, about 8% each. The tectonic stress field of the Yunnan region is near-horizontal, and the dips of earthquake fault planes are large. There are three main dynamic sources acting on the Yunnan region: one is the NE, NNE and NNW-directed acting force from Myanmar, Laos and Vietnam; the second is the SE-SSE directed force from the Sichuan and Sichuan-Yunnan rhombus block and the third is the NW-NNW directed force from the South China block. These three acting forces have controlled the faulting behavior of the main faults and the characteristics of strong earthquake activity of Yunnan and its adjacent regions.
基金Supported by the National Natural Science Foundation,China(No.31300522)the Specialized Research Fund for the Doctoral Program of Higher Education,China(No.20125103120018)+1 种基金the Scientific Research Fund of Sichuan Provincial Education Department,China(No.12ZA118)the National Key Technology R&D Program,China(No.2011BAC09B05)
文摘Bamboos are one of the fast-growing and multiple use species in the world, and thus bamboo forests/plantations play an important role in C sequestration at regional and global levels. We studied aboveground litterfall, litter decomposition and nutrient dynamics for two years in two subtropical bamboo ecosystems in Southwest China so as to test the hypothesis that litter quality determine the rate and nutrient dynamics during decomposition of different litter fractions. Mean annual total aboveground litter production ranged from 494 to 434 g m-2 in two bamboo stands (P stand, dominated by Pleioblastus amarus and H stand, hybrid bamboo dominated by Bambusa pervariabilis x Dendrocalamopsis daii). Bulk (-80%) of litter production was contributed by leaf litter in two stands followed by twigs and sheathes. Different litter fractions represented considerable variations in the rates of mass loss and nutrient release. Variation of the mass remaining after 2 years of decomposition was significantly explained by initial C/N ratio and initial P concentration. Initial concentrations of N, P, Ca, and Mg explained 57.9%, 95.0%, 99.8% and 98.1%, respectively, of the variations of these elements mass remaining after 2 years of decomposition. The patterns of nutrient dynamics and the final amount remaining were mainly determined by their initial litter substrate quality in tl^ese two subtropical bamboo plantations.
文摘This year marks the 100 th anniversary of Nelson Mandela's birth.The reason the global media reacted strongly to the news of Mandela's death five years ago can be found in his lasting contributions and his immortal spirit.Mandela's spirit is characterized by the noble ideals of opposing apartheid and achieving democracy,freedom and equality;by his philosophy of reconciliation,marked by magnanimity and forgiveness;by his principled stand for peace and justice in Africa and the world;by his political wisdom in summing up the situation and meeting the challenges of the times,evinced in his quitting office at the peak of his political life;by his thankfulness for help and concern for vulnerable groups;and by his personal charm,as reflected in his magnanimity,sense of humor,sincerity and sense of equality.These six qualities are closely connected and constitute a dialectical unity.South Africa is the birthplace of Mandela and the soil in which the Mandela spirit grew.The fact that South Africa produced a Mandela is closely connected with his historical era and the social environment,as well as the influence of countries around the world and the international support he received.Above all,however,Mandela's rise was closely tied to his noble ideals and outstanding character.In a word,the internal and external origins ofthe Mandela spirit complement and illuminate each other.The Mandela spirit is rooted in South Africa,yet it belongs to the whole world and the whole human race.Its radiant reason,dynamism and strong personal influence will continue to illuminate our world with an eternal charisma.The world of today needs the Mandela spirit more than ever.
基金funded by the National Basic Research Program of China(2012CB957704)the National Natural Science Foundation of China(41176163)+2 种基金the Specialized Research Fund for the Doctoral Program of Higher Education(201200031 10030)the Strategic Research Fund Program of Polar Science(20140301)the Project of International Cooperation and Exchanges CHINARE(IC201203)
文摘Owing to global warming,frequent ice shelf disintegration and rapid acceleration of inland ice flow have occurred in recent decades,which impacts the Antarctic mass balance and the global sea level[1].These events are closely linked to atmospheric and oceanic processes.The prolonged melt season and larger extent of melt ponds on the ice shelf surface[2],as well as enhanced basal melting caused by warmer sea water[3],will induce crevasses that
基金supported by the Chinese Academy of Sciences and China Scholarship Council(201206050103)
文摘The newly developed CRISPR(Clustered Regularly Interspaced Short Palindromic Repeats)/Cas(CRISPR-associated) system has emerged as an efficient tool for genome-editing, providing an alternative to classical mutagenesis and transgenic methods to study gene function and improve crop traits. CRISPR/Cas facilitates targeted gene editing through RNA-guided DNA cleavage followed by cellular DNA repair mechanisms that introduce sequence changes at the site of cleavage. Here we describe a detailed procedure for our previously developed and highly efficient CRISPR/Cas9 method that allows the generation of heritable-targeted gene mutations andcorrections in Arabidopsis. This protocol describes the strategies and steps for the selection of targets, design of single-guide RNA(sg RNA), vector construction and analysis of transgenic lines. We also offer a method to target two loci simultaneously using vectors containing two different sg RNAs. The principles described in this protocol can be applied to other plant species to generate stably inherited DNA modifications.
文摘This essay examines the Daoist metaphysical masters' hermeneutic misreading of the Confucian classics during the Wei and Jin Dynasties. Applying the concept of misreading as the theoretical guideline, we will first analyze the three important supporting columns of Confucian literary theory: the importance of virtue/morality, the authority of literary sages and the ontology of the classics, and then we will examine the metaphysical masters' subversion of the Confucian classics by misreading with their Daoist literary theory and concepts. In their hermeneutic misreading of the Confucian classics, the metaphysical masters in fact fused the original concepts of the Confucian classics with their contemporary Daoist hermeneutics, and the result of such a fusion is that the original meanings as the signified parted from the signifiers--the texts of the classics themselves--and were turned into repositories of contemporary Daoist meanings. In such a hermeneutic misreading, the Daoist theorists forced the Confucian theory and its ontology to gloomily withdraw from the cultural center, and gradually took the spotlight on the historical stage of the Wei and Jin Dynasties. In their open attitudes and flexible system, the metaphysical theorists constructed an age of enlightenment for the development of literary theory. With their hermeneutic misreading, the metaphys- ical literary theorists indeed broke through the world of Confucianism, won the right of expression, and voluntarily moved toward the self-fulfillment of their own system in the Wei and Jin Dynasties.