With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that： the soil total porosi...With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that： the soil total porosity was the highest in the Casuarina equisetifolia forest （46.168%）, but the lowest in the Encalyptus robusta forest （39.46%）. The soil capillary porosity was the highest in the Acacia mangium forest （22.57%）, but the lowest in the secondary forest （18.95%）. The soil water content was the highest in the C. equisetifolia forest, with a mean value of 27.85%, but the lowest in the secondary forest, with a mean value of 4.34%. The soil pH values were in the range of 4.81-6.59, the soils in the A. mangium forest, C. equisetifolia forest and E. robusta forest were strongly acidic （pH 4.5-5.5）, and the soils in the secondary forest and C. nucifera forest were weakly acidic. The soils had organic matter contents in the range of 0.34-28.68 g/kg, and showed an order of A. mangium forest〉C. equisetifolia forest〉E. robusta forest〉secondary forest〉C. nucifera forest, with a decreasing trend with the soil depth increasing. The soil total N contents were in the range of 0.10-1.63 g/kg, the A. mangium forest showed the highest soil total N contents, while the C. nucifera forest exhibited the lowest soil total N contents; the soil total P contents were in the range of 0.21-1.74 g/kg, and the E. robusta forest had the highest soil total P contents; and the soil total K contents were in the range of 0.16-2.15 g/kg, and the A. mangium forest exhibited the highest soil total K contents. The soil available P contents were in the range of 0.98-132.46 mg/kg; and the secondary forests had the highest soil available P contents; and the soil rapidly available K contents were in the range of 3.03-27.35 mg/kg, and the C. nucifera forest exhibited the highest soil rapidly available K contents. The soil ammonium N contents were in the range of 1.38-5.15 mg/kg, and the nitrate N contents were in the range were in the range of 0.56 -3.51 mg/kg. The A. mangium forest showed the highest soil nitrate N contents （with a mean value of 2.29 mg/kg） and ammonium N contents （with a mean value of 3.93 mg/kg）. For the same forest type, with the increase of soil depth, the nitrate nitrogen and ammonium nitrogen content also showed a decreasing trend.展开更多
In this paper, we propose two methods to enhance the synchronizability of a class of complex networks which do not hold the positive correlation between betweenness centrality （BC） and degree of a node, and observe ...In this paper, we propose two methods to enhance the synchronizability of a class of complex networks which do not hold the positive correlation between betweenness centrality （BC） and degree of a node, and observe other topology characteristics of the network affected by the methods. Numerical simulations show that both methods can effectively enhance the synchronizability of this kind of networks. Furthermore, we show that the maximal BC of all edges is an important factor to affect the network synchronizability, although it is not the unique factor.展开更多
We read the research article entitled Is cardiac resyn- chronisation therapy feasible, safe and beneficial in the very elderly？ with great interest. The authors emphasized that despite the average age of heart failur...We read the research article entitled Is cardiac resyn- chronisation therapy feasible, safe and beneficial in the very elderly？ with great interest. The authors emphasized that despite the average age of heart failure was 77 years in the general population of UK,patients receiving cardiac re- synchronisation therapy [with pacemaker alone （CRT-P） or with additional defibrillator capabilities （CRT-D）] were on younger ages at 72 and 67 years respectively. In the lights of this data, we agree with the authors that CRT seems to be undemtilized in the elderly patients with heart failure.展开更多
The concept of word classes （parts of speech） has always generated controversy among linguists. The earlier Prescriptive and Descriptive Schools might have set the pace for this controversy but the present dilemma i...The concept of word classes （parts of speech） has always generated controversy among linguists. The earlier Prescriptive and Descriptive Schools might have set the pace for this controversy but the present dilemma is much deeper. Learners and even teachers are sometimes at quandary as to how to proof that a particular word belongs to a particular class. This is because a word may sometimes belong to several classes, in context as in the word ＂watch＂ which can belong to different classes. This paper therefore tries to provide answers to the problem of word class classification by using a morphological and syntactical evidence to prove that English words follow a particular range of inflections and belong to strictly ordered particular categories and do not change their class arbitrarily. This is in line with the natural perfect order of homogeneity in creation which precludes a specie from merging effectively with another specie without having to undergo some fundamental changes. Other variables were also looked into and it was concluded that teachers and learners as well, can rely on this sub-categorization approach as a reliable paradigm for their assumptions concerning word classes.展开更多
Using a tunable clustering coeffcient model withoutchanging the degree distribution, we investigate the effect of clustering coefficient on synchronization of networks with both unweighted and weighted couplings. For ...Using a tunable clustering coeffcient model withoutchanging the degree distribution, we investigate the effect of clustering coefficient on synchronization of networks with both unweighted and weighted couplings. For several typical categories of complex networks, the more triangles are in the networks, the worse the synchronizability of the networks is.展开更多
This research presents complete phenolic compounds and biological activity of Tamarix pauciovulata J. Gay, an endemic Saharan species. The antioxidant assays revealed that crude extract showed strong DPPH scavenging a...This research presents complete phenolic compounds and biological activity of Tamarix pauciovulata J. Gay, an endemic Saharan species. The antioxidant assays revealed that crude extract showed strong DPPH scavenging activity （IC50 = 49.357 μg/mL） but in reducing power and hydrogen peroxide scavenging activity, butanolic and ethyl acetate fractions have a potent ferrous ion-chelating ability in particularly the butanolic fraction （63.18% reduced power at 50 μg/mL） and a powerful scavenging activity on hydrogen peroxide in particularly ethyl acetate fraction （IC50 = 0.205 μg/mL）. The phenolic compounds of Tamarix pauciovulata leaves were analyzed by HPLC-UV. The major phenolic of leaf extracts are syringic acid （1.07 g/100g）, quercetin （34.1 mg/100g）, kaempferol （5.77 mg/100g）, isorhamnetin （5 mg/100g）. Others phenols were identified such as isoquercetin, catechin, epicatechin and its derivatives. Results indicated that the leaves extracts from Tamarix pauciovulata have great capacities to prevent diseases caused by the overproduction of radicals and can become important source of dietary compounds with health protective potential.展开更多
Ecdysis is a comm on phe nomenon that happe ns throughout the life phase of the giant freshwater prawn Macrobrachium rosenbergii.It is vital to better understand the correlation between cannibalism and biochemical com...Ecdysis is a comm on phe nomenon that happe ns throughout the life phase of the giant freshwater prawn Macrobrachium rosenbergii.It is vital to better understand the correlation between cannibalism and biochemical compound that exists during the moulting process.The objective of the present study was to determine the amino acid profile released by M.rosenbergii during the ecdysis process that promotes cannibalism.To accomplish this,changes in amino acid levels(total amino acid(TAA)and free amino acid(FAA))of tissue muscle,exoskeleton,and sample water of culture medium from the moulting(E-stage)and non-moulting(C-stage)prawns were analysed using highperformanee liquid chromatography(HPLC).Comparison study revealed that among the TAA compounds,proline and sarcosine of tissues from moulting prawn were found at the highest levels.The level of FAA from water that contains moulting prawns(E-stage)was dominated by tryptophan and proline.Significant values obtained in the present study suggested that these amino acid compounds act as a chemical cue to promote cannibalism in M.rosenbergii during ecdysis.The knowledge of compositions and compounds that were released during the moulting process should be helpful for better understanding of the mechanism and chemical cues that play roles on triggering cannibalism,and also for future dietary man ipulati on to improve feeding efficie ncies and feeding man agement,which in directly impacts productivity and profitability.展开更多
The hydrogen isotopic composition(δD) of n-alkanes in lacustrine sediments is widely used in palaeoenvironmental studies, but the heterogeneous origins and relative contributions of these lipids provide challenges fo...The hydrogen isotopic composition(δD) of n-alkanes in lacustrine sediments is widely used in palaeoenvironmental studies, but the heterogeneous origins and relative contributions of these lipids provide challenges for the interpretation of the increasing dataset as an environment and climatic proxy. We systematically investigated n-alkane δD values from 51 submerged plants(39 Potamogeton, 1 Myriophyllum, and 11 Ruppia), 13 algae(5 Chara, 3 Cladophora, and 5 Spirogyra) and 20 terrestrial plants(10 grasses and 10 shrubs) in and around 15 lakes on the Tibetan Plateau. Our results demonstrate that δD values of C_(29) nalkane are correlated significantly with the lake water δD values both for algae(R^2=0.85, p<0.01, n=9) and submerged plants(R^2=0.90, p<0.01, n=25), indicating that δD values of these algae and submerged plants reflect the δD variation of lake water. We find that apparent hydrogen isotope fractionation factors between individual n-alkanes and water(εa/w) are not constant among different algae and submerged plants, as well as in a single genus under different liminological conditions, indicating that the biosynthesis or environmental conditions(e.g. salinity) may affect their δD values. The δD values of submerged plant Ruppia in the Xiligou Lake(a closed lake) are significant enriched in D than those of terrestrial grasses around the lake(one-way ANOVA,p<0.01), but the algae Chara in the Keluke Lake(an open lake) display similar δD values with grasses around the lake(one-way ANOVA, p=0.826>0.05), suggesting that the n-alkane δD values of the algae and submerged plants record the signal of D enrichment in lake water relative to precipitation only in closed lakes in arid and semi-arid area. For each algae and submerged plant sample, we find uniformed δD values of different chain length n-alkanes, implying that, in combination with other proxies such as Paq and Average Chain Length, the offset between the δD values of different chain length n-alkanes can help determine the source of sedimentary n-alkanes as well as inferring the hydrological characteristics of an ancient lake basin(open vs closed lake).展开更多
The present article provides mathematical modeling for melting heat and thermal radiation in stagnationpoint flow of carbon nanotubes towards a nonlinear stretchable surface of variable thickness. The process of homog...The present article provides mathematical modeling for melting heat and thermal radiation in stagnationpoint flow of carbon nanotubes towards a nonlinear stretchable surface of variable thickness. The process of homogeneousheterogeneous reactions is considered. Diffusion coefficients are considered equal for both reactant and autocatalyst.Water and gasoline oil are taken as base fluids. The conversion of partial differential system to ordinary differential system is done by suitable transformations. Optimal homotopy technique is employed for the solutions development of velocity, temperature, concentration, skin friction and local Nusselt number. Graphical results for various values of pertinent parameters are displayed and discussed. Our results indicate that the skin friction coefficient and local Nusselt number are enhanced for larger values of nanoparticles volume fraction.展开更多
The oxygen isotope ratios （δ18O） preserved in marine sediments have been widely used to reconstruct past ocean temperatures. However, there remain significant uncertainties associated with this method, owing to ass...The oxygen isotope ratios （δ18O） preserved in marine sediments have been widely used to reconstruct past ocean temperatures. However, there remain significant uncertainties associated with this method, owing to assumptions about the δ18O of ancient seawater which affects the temperature inferred from sediment δ18O records. In this study, oxygen isotope compositions of phosphate in teeth and bones from five different modem cetacean species, including sperm whale, pygmy sperm whale, short-finned pilot whale, killer whale, and Cuvier＇s beaked whale, and three fossil whales were determined. The data were used to assess whether the oxygen isotope ratios of biogenic phosphate （δ18Op） from cetaceans are a reliable proxy for the oxygen isotopic composition of ocean water （δ18Ow）. The δ18Op values of modem cetaceans range from 15.5 ‰ to 21.3 ‰, averaging （19.6 ‰ ±0.8 ‰） （n = 136）.Using a greatly expanded global cetacean δ18Op dataset, the following regression equation is derived for cetaceans： δ18Ow = 0.95317 （4-0.03293） δ18Op- 17.971 （＋0.605）, r = 0.97253. The new equation, when applied to fossil teeth and bones, yielded reasonable estimates of ancient seawater δ18Ow values. Intra-tooth isotopic variations were observed within individual teeth. Among the selected species, the killer whale （O. orca） has largest intra-tooth δ18Op preference and migratory the lowest δ18Op values and the variation, reflecting its habitat behavior. The results show that oxygen isotope analysis of phosphate in cetacean teeth and dense ear bones provides a useful tool for reconstructing the oxygen isotopic composition of seawater and for examining environmental preferences （including migratory behavior） of both modem and ancient whales.展开更多
基金Supported by Special Fund for Technological Development and Research of Provincial Scientific Research Institutions(KYYS-2015-16)~~
文摘With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that： the soil total porosity was the highest in the Casuarina equisetifolia forest （46.168%）, but the lowest in the Encalyptus robusta forest （39.46%）. The soil capillary porosity was the highest in the Acacia mangium forest （22.57%）, but the lowest in the secondary forest （18.95%）. The soil water content was the highest in the C. equisetifolia forest, with a mean value of 27.85%, but the lowest in the secondary forest, with a mean value of 4.34%. The soil pH values were in the range of 4.81-6.59, the soils in the A. mangium forest, C. equisetifolia forest and E. robusta forest were strongly acidic （pH 4.5-5.5）, and the soils in the secondary forest and C. nucifera forest were weakly acidic. The soils had organic matter contents in the range of 0.34-28.68 g/kg, and showed an order of A. mangium forest〉C. equisetifolia forest〉E. robusta forest〉secondary forest〉C. nucifera forest, with a decreasing trend with the soil depth increasing. The soil total N contents were in the range of 0.10-1.63 g/kg, the A. mangium forest showed the highest soil total N contents, while the C. nucifera forest exhibited the lowest soil total N contents; the soil total P contents were in the range of 0.21-1.74 g/kg, and the E. robusta forest had the highest soil total P contents; and the soil total K contents were in the range of 0.16-2.15 g/kg, and the A. mangium forest exhibited the highest soil total K contents. The soil available P contents were in the range of 0.98-132.46 mg/kg; and the secondary forests had the highest soil available P contents; and the soil rapidly available K contents were in the range of 3.03-27.35 mg/kg, and the C. nucifera forest exhibited the highest soil rapidly available K contents. The soil ammonium N contents were in the range of 1.38-5.15 mg/kg, and the nitrate N contents were in the range were in the range of 0.56 -3.51 mg/kg. The A. mangium forest showed the highest soil nitrate N contents （with a mean value of 2.29 mg/kg） and ammonium N contents （with a mean value of 3.93 mg/kg）. For the same forest type, with the increase of soil depth, the nitrate nitrogen and ammonium nitrogen content also showed a decreasing trend.
基金The project supported by National Natural Science Foundation of China under Grant Nos.70431002 and 60674045
文摘In this paper, we propose two methods to enhance the synchronizability of a class of complex networks which do not hold the positive correlation between betweenness centrality （BC） and degree of a node, and observe other topology characteristics of the network affected by the methods. Numerical simulations show that both methods can effectively enhance the synchronizability of this kind of networks. Furthermore, we show that the maximal BC of all edges is an important factor to affect the network synchronizability, although it is not the unique factor.
文摘We read the research article entitled Is cardiac resyn- chronisation therapy feasible, safe and beneficial in the very elderly？ with great interest. The authors emphasized that despite the average age of heart failure was 77 years in the general population of UK,patients receiving cardiac re- synchronisation therapy [with pacemaker alone （CRT-P） or with additional defibrillator capabilities （CRT-D）] were on younger ages at 72 and 67 years respectively. In the lights of this data, we agree with the authors that CRT seems to be undemtilized in the elderly patients with heart failure.
文摘The concept of word classes （parts of speech） has always generated controversy among linguists. The earlier Prescriptive and Descriptive Schools might have set the pace for this controversy but the present dilemma is much deeper. Learners and even teachers are sometimes at quandary as to how to proof that a particular word belongs to a particular class. This is because a word may sometimes belong to several classes, in context as in the word ＂watch＂ which can belong to different classes. This paper therefore tries to provide answers to the problem of word class classification by using a morphological and syntactical evidence to prove that English words follow a particular range of inflections and belong to strictly ordered particular categories and do not change their class arbitrarily. This is in line with the natural perfect order of homogeneity in creation which precludes a specie from merging effectively with another specie without having to undergo some fundamental changes. Other variables were also looked into and it was concluded that teachers and learners as well, can rely on this sub-categorization approach as a reliable paradigm for their assumptions concerning word classes.
基金The project partly supported by National Natural Science Foundation for Distinguished Young Scholars of China under Grant No. 60225013, National Natural Science Foundation of China under Grants Nos. 70271072, 70431002, and 90412004, and Shanghai RisingStar Program under Grant No.05QMX1436Author （X. Li） also acknowledges the support from the Alexander von Humboldt Foundation.
文摘Using a tunable clustering coeffcient model withoutchanging the degree distribution, we investigate the effect of clustering coefficient on synchronization of networks with both unweighted and weighted couplings. For several typical categories of complex networks, the more triangles are in the networks, the worse the synchronizability of the networks is.
文摘This research presents complete phenolic compounds and biological activity of Tamarix pauciovulata J. Gay, an endemic Saharan species. The antioxidant assays revealed that crude extract showed strong DPPH scavenging activity （IC50 = 49.357 μg/mL） but in reducing power and hydrogen peroxide scavenging activity, butanolic and ethyl acetate fractions have a potent ferrous ion-chelating ability in particularly the butanolic fraction （63.18% reduced power at 50 μg/mL） and a powerful scavenging activity on hydrogen peroxide in particularly ethyl acetate fraction （IC50 = 0.205 μg/mL）. The phenolic compounds of Tamarix pauciovulata leaves were analyzed by HPLC-UV. The major phenolic of leaf extracts are syringic acid （1.07 g/100g）, quercetin （34.1 mg/100g）, kaempferol （5.77 mg/100g）, isorhamnetin （5 mg/100g）. Others phenols were identified such as isoquercetin, catechin, epicatechin and its derivatives. Results indicated that the leaves extracts from Tamarix pauciovulata have great capacities to prevent diseases caused by the overproduction of radicals and can become important source of dietary compounds with health protective potential.
基金Fundamental Research Grant Scheme from the Ministry of Higher Education,Malaysia(No.59324)。
文摘Ecdysis is a comm on phe nomenon that happe ns throughout the life phase of the giant freshwater prawn Macrobrachium rosenbergii.It is vital to better understand the correlation between cannibalism and biochemical compound that exists during the moulting process.The objective of the present study was to determine the amino acid profile released by M.rosenbergii during the ecdysis process that promotes cannibalism.To accomplish this,changes in amino acid levels(total amino acid(TAA)and free amino acid(FAA))of tissue muscle,exoskeleton,and sample water of culture medium from the moulting(E-stage)and non-moulting(C-stage)prawns were analysed using highperformanee liquid chromatography(HPLC).Comparison study revealed that among the TAA compounds,proline and sarcosine of tissues from moulting prawn were found at the highest levels.The level of FAA from water that contains moulting prawns(E-stage)was dominated by tryptophan and proline.Significant values obtained in the present study suggested that these amino acid compounds act as a chemical cue to promote cannibalism in M.rosenbergii during ecdysis.The knowledge of compositions and compounds that were released during the moulting process should be helpful for better understanding of the mechanism and chemical cues that play roles on triggering cannibalism,and also for future dietary man ipulati on to improve feeding efficie ncies and feeding man agement,which in directly impacts productivity and profitability.
基金supported by the National Natural Science Foundation of China(Grant No.41573005)National Basic Research Programme of China(Grant No.2013CB955901)Key Program of the Chinese Academy of Sciences(Grant No.QYZDY-SSWDQC001)
文摘The hydrogen isotopic composition(δD) of n-alkanes in lacustrine sediments is widely used in palaeoenvironmental studies, but the heterogeneous origins and relative contributions of these lipids provide challenges for the interpretation of the increasing dataset as an environment and climatic proxy. We systematically investigated n-alkane δD values from 51 submerged plants(39 Potamogeton, 1 Myriophyllum, and 11 Ruppia), 13 algae(5 Chara, 3 Cladophora, and 5 Spirogyra) and 20 terrestrial plants(10 grasses and 10 shrubs) in and around 15 lakes on the Tibetan Plateau. Our results demonstrate that δD values of C_(29) nalkane are correlated significantly with the lake water δD values both for algae(R^2=0.85, p<0.01, n=9) and submerged plants(R^2=0.90, p<0.01, n=25), indicating that δD values of these algae and submerged plants reflect the δD variation of lake water. We find that apparent hydrogen isotope fractionation factors between individual n-alkanes and water(εa/w) are not constant among different algae and submerged plants, as well as in a single genus under different liminological conditions, indicating that the biosynthesis or environmental conditions(e.g. salinity) may affect their δD values. The δD values of submerged plant Ruppia in the Xiligou Lake(a closed lake) are significant enriched in D than those of terrestrial grasses around the lake(one-way ANOVA,p<0.01), but the algae Chara in the Keluke Lake(an open lake) display similar δD values with grasses around the lake(one-way ANOVA, p=0.826>0.05), suggesting that the n-alkane δD values of the algae and submerged plants record the signal of D enrichment in lake water relative to precipitation only in closed lakes in arid and semi-arid area. For each algae and submerged plant sample, we find uniformed δD values of different chain length n-alkanes, implying that, in combination with other proxies such as Paq and Average Chain Length, the offset between the δD values of different chain length n-alkanes can help determine the source of sedimentary n-alkanes as well as inferring the hydrological characteristics of an ancient lake basin(open vs closed lake).
文摘The present article provides mathematical modeling for melting heat and thermal radiation in stagnationpoint flow of carbon nanotubes towards a nonlinear stretchable surface of variable thickness. The process of homogeneousheterogeneous reactions is considered. Diffusion coefficients are considered equal for both reactant and autocatalyst.Water and gasoline oil are taken as base fluids. The conversion of partial differential system to ordinary differential system is done by suitable transformations. Optimal homotopy technique is employed for the solutions development of velocity, temperature, concentration, skin friction and local Nusselt number. Graphical results for various values of pertinent parameters are displayed and discussed. Our results indicate that the skin friction coefficient and local Nusselt number are enhanced for larger values of nanoparticles volume fraction.
基金supported by US National Science Foundation Cooperative Agreement No.DMR-1157490 and the State of Floridathe State of Florida.The Stable Isotope Lab was established with grants from the US National Science Foundation(EAR-0824628EAR-0517806 and EAR-0236357)
文摘The oxygen isotope ratios （δ18O） preserved in marine sediments have been widely used to reconstruct past ocean temperatures. However, there remain significant uncertainties associated with this method, owing to assumptions about the δ18O of ancient seawater which affects the temperature inferred from sediment δ18O records. In this study, oxygen isotope compositions of phosphate in teeth and bones from five different modem cetacean species, including sperm whale, pygmy sperm whale, short-finned pilot whale, killer whale, and Cuvier＇s beaked whale, and three fossil whales were determined. The data were used to assess whether the oxygen isotope ratios of biogenic phosphate （δ18Op） from cetaceans are a reliable proxy for the oxygen isotopic composition of ocean water （δ18Ow）. The δ18Op values of modem cetaceans range from 15.5 ‰ to 21.3 ‰, averaging （19.6 ‰ ±0.8 ‰） （n = 136）.Using a greatly expanded global cetacean δ18Op dataset, the following regression equation is derived for cetaceans： δ18Ow = 0.95317 （4-0.03293） δ18Op- 17.971 （＋0.605）, r = 0.97253. The new equation, when applied to fossil teeth and bones, yielded reasonable estimates of ancient seawater δ18Ow values. Intra-tooth isotopic variations were observed within individual teeth. Among the selected species, the killer whale （O. orca） has largest intra-tooth δ18Op preference and migratory the lowest δ18Op values and the variation, reflecting its habitat behavior. The results show that oxygen isotope analysis of phosphate in cetacean teeth and dense ear bones provides a useful tool for reconstructing the oxygen isotopic composition of seawater and for examining environmental preferences （including migratory behavior） of both modem and ancient whales.
