Fire disturbances are increasing under global climate change and ecological transformations of forests are occurring.Specifically,shifts from productive closed-canopy feather moss forests to low-productivity open-cano...Fire disturbances are increasing under global climate change and ecological transformations of forests are occurring.Specifically,shifts from productive closed-canopy feather moss forests to low-productivity open-canopy lichen(Cladonia spp.)woodlands have been observed in boreal forests of eastern Canada.It has been hypothesized that high severity of fires would be the cause of this change,but this is difficult to validate a posteriori on mature forest stands.Because charcoal properties are affected by fire severity,we have put forward the hypothesis that the amount and physicochemical properties of charcoal(C,N,H,O,ash,surface area)would be different and indicative of a greater fire severity for open-canopy forests compared to closed canopy ones.Our hypothesis was partly validated in that the amount of charcoal found on the ground of closed-canopy forests was greater than that of open-canopy forests.However,the physicochemical properties were not different,albeit a greater variability of charcoal properties for open canopy stands.These results do not allow us to fully validate or reject our hypothesis on the role of fire severity in the shift between open and closed canopy stands.However,they suggest that the variability in fire conditions as well as the amounts of charcoal produced are different between the two ecosystem types.Furthermore,considering the role that biochar may play in improving soil conditions and promoting vegetation restoration,our results suggest that charcoal may play a role in maintaining these two stable alternative ecosystem states.展开更多
A study was conducted to evaluate the cultivable filamentous fungal diversity in organic layers (L, F, and H layers) and A1 layer of two main forest types, Pinus massoniana and Liguidambar formasana mixed forest and Q...A study was conducted to evaluate the cultivable filamentous fungal diversity in organic layers (L, F, and H layers) and A1 layer of two main forest types, Pinus massoniana and Liguidambar formasana mixed forest and Quercus variabilis forest, in Zijin Mountain(325?N, 11848?E), Nanjing, China. A total of 67 taxa comprising 56 Deuteromycetes, 3 Zygomycetes, 5 Asco-mycetes and 3 unidentified fungi were recognized from samples from the forest floor of the two forest types. The most abundant group was Deuteromycetes. The dominant genera in both forests were Alternaria sp., Aspergillus sp., Cladosporium sp., Mucor sp., Penicillium sp., Rhizopus sp., Gliocladium sp. and Trichoderma spp. The fungal diversity was higher in the mixed forest than that in Q. variabilis forest. For both forest types, the maximum fungal diversity was found in layer F and there existed significantly different in fungal diversity between layer F and layer L. In the mixed forest, richness of fungi isolated from needle litter (P. massoniana) was lower than that from leaf litter (L. formasana). The richness of fungi from needle litter increased with the in-crease of forest floor depth, but for leaf litter, the fungal diversity decreased with the depth of forest floor. The co-species of fungi from the two forest types, as well as from two kinds of litters in mixed forest, increased with the depth of the forest floor. The succession of fungi along with the process of decomposition was discussed here. The results also showed that litter quality was a critical factor affecting fungal diversity.展开更多
In this paper, we take Guizhou Province (the heart of southwestern Karst region in China) as the research object. By establishing gray forecasting model and time series forecasting model, we conduct the accuracy test ...In this paper, we take Guizhou Province (the heart of southwestern Karst region in China) as the research object. By establishing gray forecasting model and time series forecasting model, we conduct the accuracy test on the actual production capacity of land and the forecasted production capacity of land in 2007 and 2008, and then conduct comprehensive forecast of the land production potential in Guizhou Province in 2020. On this basis, considering the nutritional standards needed by three kinds of life type (dressing warmly and eating one's fill, well-off life, relatively affluent life), we evaluate the land production potential in Guizhou Province under the project of returning farmland to forest. Based on the evaluation results, we put forth the relevant recommendations for achieving sustainable land use in the context of returning farmland to forest in Guizhou Province.展开更多
We put forward an enlightening view on repulsive force between antimatter:Antimatter repels each other,and the repulsive force is proportional to the product of their masses and inversely proportional to the square of...We put forward an enlightening view on repulsive force between antimatter:Antimatter repels each other,and the repulsive force is proportional to the product of their masses and inversely proportional to the square of the distance between them;There is no gravitational or anti-gravitational interaction between antimatter and positive matter.As their applications,we explain the Big Bang process in a new light.展开更多
With the successful hosting of the Beijing Olympic Games in 2008 and the World Exposition Shanghai China 2010,English,next to our mother tongue,has become the most important language in China.Therefore,learning Englis...With the successful hosting of the Beijing Olympic Games in 2008 and the World Exposition Shanghai China 2010,English,next to our mother tongue,has become the most important language in China.Therefore,learning English well is very important for most Chinese people.However,learning a foreign language well is not easy.We have to master several learning strategies and methods to learn it successfully.This paper will help all the foreign language learners to find the effective way in learning the second foreign languge.The paper mainly talks about two aspects:improving the abilities in listening,speaking and reading in order to communicate well;developing the ability of writing in English and perfecting the function of social communication.It gives out the concrete methods in listening,speaking,reading,writing,and translating.The authors hope that the paper would be helpful in assisting the foreign language learners to learn and master the second foreign language.展开更多
The Naga Hills Ophiolite(NHO)belt in the Indo-Myanmar range(IMR)represents a segment of Tethyan oceanic crust and upper mantle that was involved in an eastward convergence and collision of the Indian Plate with the Bu...The Naga Hills Ophiolite(NHO)belt in the Indo-Myanmar range(IMR)represents a segment of Tethyan oceanic crust and upper mantle that was involved in an eastward convergence and collision of the Indian Plate with the Burmese Plate during the Late Cretaceous-Eocene.Here,we present a detailed petrological and geochemical account for the mantle and crustal sections of NHO,northeastern India to address(i)the mantle processes and tectonic regimes involved in their genesis and(ii)their coherence in terms of the thermo-tectonic evolution of Tethyan oceanic crust and upper mantle.The NHO suite comprises well preserved crustal and mantle sections discretely exposed at Moki,Ziphu,Molen,Washelo and Lacham areas.The ultramafic-mafic lithologies of NHO are mineralogically composed of variable proportions of olivine,orthopyroxene,clinopyroxene and plagioclase.The primary igneous textures for the mantle peridotites have been overprinted by extensive serpentinisation whereas the crustal section rocks reflect crystal cumulation in a magma chamber.Chondrite normalised REE profiles for the cumulate peridotite-olivine gabbro-gabbro assemblage constituting the crustal section of NHO show flat to depleted LREE patterns consistent with their generation from depleted MORB-type precursor melt in an extensional tectonic setting,while the mantle peridotites depict U-shaped REE patterns marked by relative enrichment of LREE and HREE over MREE.These features collectively imply a dual role of depleted MORB-type and enriched arc-type mantle components for their genesis with imprints of melt-rock and fluid-rock interactions.Tectonically,studied lithologies from NHO correspond to a boninitic to slab-proximal Island Arc Tholeiite affinity thereby conforming to an intraoceanic supra subduction zone(SSZ)fore-arc regime coherent with the subduction initiation process.The geochemical attributes for the crustal and mantle sections of NHO as mirrored by Zr/Hf,Zr/Sm,Nb/Ta,Zr/Nb,Nb/U,Ba/Nb,Ba/Th,Ba/La and Nd/Hf ratios propound a two-stage petrogenetic process:(i)a depleted fore arc basalt(FAB)type tholeiitic melt parental to the crustal lithologies was extracted from the upwelling asthenospheric mantle at SSZ fore-arc extensional regime thereby rendering a refractory residual upper mantle;(ii)the crust and upper mantle of the SSZ fore arc were progressively refertilised by boninitic melts generated in response to subduction initiation and slab-dehydration.The vestiges of Tethyan oceanic lithosphere preserved in NHO represent an accreted intra-oceanic fore arc crust and upper mantle section which records a transitional geodynamic evolution in a SSZ regime marked by subduction initiation,fore arc extension and arc-continent accretion.展开更多
Objective： To screen and identify key genes differentially displayed in mouse fore stomach carcinoma, in order to elucidate the molecular mechanism underlying carcinogenesis. Methods： The animal models complied wit...Objective： To screen and identify key genes differentially displayed in mouse fore stomach carcinoma, in order to elucidate the molecular mechanism underlying carcinogenesis. Methods： The animal models complied with each period of NIH mouse fore stomach carcinoma induced by N-Nitrososarcosineethylester （NSEE） were used in this study. The mice were euthanized on days 14, 28, 56, 77 and 84, respectively, after NSEE-piped treatment, and classified according to their pathologies. The differentially expressed genes were isolated from both normal and morbid tissues by mRNA differential display technique and screened by using Reverse Northern blot. Bioinformatics were employed to analyze the results observed. After identification, ten fragments were cloned and matched with GENEBANK database through homologous analysis. Results： One gene was found identical to splicing factor 3b subunit 1 （Sf3bl）, while seven fragments hold the homology of known cDNA clones. In contrast, other two fragments had extremely low identity to any genes registered in GENBANK databases. Conclusion： It is the first time to demonstrate in this study that splicing factor3b, subunitl （Sf3bl） is related to mouse fore stomach carcinoma. Furthermore, ESC-3 and ESC-4 are suggested to contribute to the development of mouse fore stomach carcinoma, thus may be candidates of new targets of oncogenes.展开更多
This paper investigates characteristics of ironless permanent magnet linear synchronous motor(PMLSM)based on Halbach array used for medium-speed(200km/h)maglev train.Long primary ironless coil is laid in the middle of...This paper investigates characteristics of ironless permanent magnet linear synchronous motor(PMLSM)based on Halbach array used for medium-speed(200km/h)maglev train.Long primary ironless coil is laid in the middle of track and the Halbach permanent magnet array is attached to the bottom of each bogie as a source of traction,U-shape electromagnets at the both sides of the train for levitation.Two dimensional analytical model of single-sided ironless PMLSM based on Halbach array is established,using linear overlay method,the no-load air gap magnetic field is calculated firstly,winding current density distribution is obtained for calculating the characteristics of thrust and normal force against power angle,including force characteristics with equal and unequal pole pitch,the influence of steel sleeper,etc.Besides,the mathematical model for this type motor is built by 3D finite element method,the traction characteristics of medium-speed maglev under maximum speed 200km/h are calculated.The characteristics of this type motor are satisfactory owing to there is no detent force in the motor and thrust force reach maximum meanwhile normal force can be eliminated.Calculation method is verified by comparing finite element results,experimental result on a 200kW type motor further validates the accuracy of calculation and some important conclusions are obtained.展开更多
The significance and status of the teachers'professional development make the education system and the society pay more and more attentions.The article elaborates the internal contact of curriculum discourse and t...The significance and status of the teachers'professional development make the education system and the society pay more and more attentions.The article elaborates the internal contact of curriculum discourse and teachers'professional development from a few respects such as the rationality of curriculum discourse,the long-term nature of the teachers'professional development and many factors affecting the teachers'professional development.The article also analyzes the external and internal factors influencing Tibet foreign language teachers'professional development,and puts forward the corresponding countermeasures in the light of these problems.展开更多
Objective： To find out the relationship of the expressions of proliferating cell nuclear antigen （proliferating cell nuclear antigen, PCNA）, alkaline phosphotase （alkaline phosphotase, AKP） and acid phosphotase ...Objective： To find out the relationship of the expressions of proliferating cell nuclear antigen （proliferating cell nuclear antigen, PCNA）, alkaline phosphotase （alkaline phosphotase, AKP） and acid phosphotase （acid phosphotase, ACP） with the development of mouse fore stomach cancerization. Methods： The animal models, including the various stages during the development of NIH mouse fore stomach carcinoma, were made by N-Nitrososarcosineethylester （N-Nitrososarcosineethylester, NSEE）. The mice were sacrificed on the 14th, 28th, 42nd, 56th, 70th and 84th days respectively after mice were irrigated with NSEE. The fore stomach was taken out and dissected. The methods of histopathology, immunohistochemistry and isoenzyme electrophoresis were adopted to study the dynamic changes of cell shape and expression of PCNA, AKP and ACP. Results： On the 42nd and 56th days after NSEE treatment, the expression of PCNA increased gradually along with the cancerization. Comparing with the control, there were significant differences （P〈0.05）. On the 70th and 84th days, the expression of PCNA increased further （compared with the control P〈0.01）. The activity of AKP increased gradually along with the cancerization. On the 14th, 28th, 42nd and 56th days, there were significant differences （P〈0.05）; on the 70th and 84th days, the activity of AKP increased further （P〈0.01）. The activity of ACP also increased on the 14th, 28th, 42nd and 56th days, and there were significant differences on the 70th days （P〈0.05） and on the 84th days （P〈0.01） compared with the control. Conclusion： During the carcinogenesis of NIH mouse fore stomach, the expressions of PCNA, AKP and ACP increased gradually and were consisted with the changes of cell shapes.展开更多
基金supported by the MITACS Accelerate grant with Greenfirst,industry partner in La Sarre,QC,Canada.
文摘Fire disturbances are increasing under global climate change and ecological transformations of forests are occurring.Specifically,shifts from productive closed-canopy feather moss forests to low-productivity open-canopy lichen(Cladonia spp.)woodlands have been observed in boreal forests of eastern Canada.It has been hypothesized that high severity of fires would be the cause of this change,but this is difficult to validate a posteriori on mature forest stands.Because charcoal properties are affected by fire severity,we have put forward the hypothesis that the amount and physicochemical properties of charcoal(C,N,H,O,ash,surface area)would be different and indicative of a greater fire severity for open-canopy forests compared to closed canopy ones.Our hypothesis was partly validated in that the amount of charcoal found on the ground of closed-canopy forests was greater than that of open-canopy forests.However,the physicochemical properties were not different,albeit a greater variability of charcoal properties for open canopy stands.These results do not allow us to fully validate or reject our hypothesis on the role of fire severity in the shift between open and closed canopy stands.However,they suggest that the variability in fire conditions as well as the amounts of charcoal produced are different between the two ecosystem types.Furthermore,considering the role that biochar may play in improving soil conditions and promoting vegetation restoration,our results suggest that charcoal may play a role in maintaining these two stable alternative ecosystem states.
基金This paper was supported by Chinese Program for High Technology Research and Development (2003AA209030) Scien-tific Research Foundation for doctoral supervising laboratory State Education Ministry (20030284044) and National Natural Sc
文摘A study was conducted to evaluate the cultivable filamentous fungal diversity in organic layers (L, F, and H layers) and A1 layer of two main forest types, Pinus massoniana and Liguidambar formasana mixed forest and Quercus variabilis forest, in Zijin Mountain(325?N, 11848?E), Nanjing, China. A total of 67 taxa comprising 56 Deuteromycetes, 3 Zygomycetes, 5 Asco-mycetes and 3 unidentified fungi were recognized from samples from the forest floor of the two forest types. The most abundant group was Deuteromycetes. The dominant genera in both forests were Alternaria sp., Aspergillus sp., Cladosporium sp., Mucor sp., Penicillium sp., Rhizopus sp., Gliocladium sp. and Trichoderma spp. The fungal diversity was higher in the mixed forest than that in Q. variabilis forest. For both forest types, the maximum fungal diversity was found in layer F and there existed significantly different in fungal diversity between layer F and layer L. In the mixed forest, richness of fungi isolated from needle litter (P. massoniana) was lower than that from leaf litter (L. formasana). The richness of fungi from needle litter increased with the in-crease of forest floor depth, but for leaf litter, the fungal diversity decreased with the depth of forest floor. The co-species of fungi from the two forest types, as well as from two kinds of litters in mixed forest, increased with the depth of the forest floor. The succession of fungi along with the process of decomposition was discussed here. The results also showed that litter quality was a critical factor affecting fungal diversity.
基金Supported by 2009 Youth Project of Social Science Planning in Guizhou Province (09GHQNHQ04)Agricultural Scientific and Technological Project in Guizhou Province (20103014)
文摘In this paper, we take Guizhou Province (the heart of southwestern Karst region in China) as the research object. By establishing gray forecasting model and time series forecasting model, we conduct the accuracy test on the actual production capacity of land and the forecasted production capacity of land in 2007 and 2008, and then conduct comprehensive forecast of the land production potential in Guizhou Province in 2020. On this basis, considering the nutritional standards needed by three kinds of life type (dressing warmly and eating one's fill, well-off life, relatively affluent life), we evaluate the land production potential in Guizhou Province under the project of returning farmland to forest. Based on the evaluation results, we put forth the relevant recommendations for achieving sustainable land use in the context of returning farmland to forest in Guizhou Province.
文摘We put forward an enlightening view on repulsive force between antimatter:Antimatter repels each other,and the repulsive force is proportional to the product of their masses and inversely proportional to the square of the distance between them;There is no gravitational or anti-gravitational interaction between antimatter and positive matter.As their applications,we explain the Big Bang process in a new light.
文摘With the successful hosting of the Beijing Olympic Games in 2008 and the World Exposition Shanghai China 2010,English,next to our mother tongue,has become the most important language in China.Therefore,learning English well is very important for most Chinese people.However,learning a foreign language well is not easy.We have to master several learning strategies and methods to learn it successfully.This paper will help all the foreign language learners to find the effective way in learning the second foreign languge.The paper mainly talks about two aspects:improving the abilities in listening,speaking and reading in order to communicate well;developing the ability of writing in English and perfecting the function of social communication.It gives out the concrete methods in listening,speaking,reading,writing,and translating.The authors hope that the paper would be helpful in assisting the foreign language learners to learn and master the second foreign language.
基金the funds from Department of Science and Technology,Govt.of India under ECR/2018/000309 project。
文摘The Naga Hills Ophiolite(NHO)belt in the Indo-Myanmar range(IMR)represents a segment of Tethyan oceanic crust and upper mantle that was involved in an eastward convergence and collision of the Indian Plate with the Burmese Plate during the Late Cretaceous-Eocene.Here,we present a detailed petrological and geochemical account for the mantle and crustal sections of NHO,northeastern India to address(i)the mantle processes and tectonic regimes involved in their genesis and(ii)their coherence in terms of the thermo-tectonic evolution of Tethyan oceanic crust and upper mantle.The NHO suite comprises well preserved crustal and mantle sections discretely exposed at Moki,Ziphu,Molen,Washelo and Lacham areas.The ultramafic-mafic lithologies of NHO are mineralogically composed of variable proportions of olivine,orthopyroxene,clinopyroxene and plagioclase.The primary igneous textures for the mantle peridotites have been overprinted by extensive serpentinisation whereas the crustal section rocks reflect crystal cumulation in a magma chamber.Chondrite normalised REE profiles for the cumulate peridotite-olivine gabbro-gabbro assemblage constituting the crustal section of NHO show flat to depleted LREE patterns consistent with their generation from depleted MORB-type precursor melt in an extensional tectonic setting,while the mantle peridotites depict U-shaped REE patterns marked by relative enrichment of LREE and HREE over MREE.These features collectively imply a dual role of depleted MORB-type and enriched arc-type mantle components for their genesis with imprints of melt-rock and fluid-rock interactions.Tectonically,studied lithologies from NHO correspond to a boninitic to slab-proximal Island Arc Tholeiite affinity thereby conforming to an intraoceanic supra subduction zone(SSZ)fore-arc regime coherent with the subduction initiation process.The geochemical attributes for the crustal and mantle sections of NHO as mirrored by Zr/Hf,Zr/Sm,Nb/Ta,Zr/Nb,Nb/U,Ba/Nb,Ba/Th,Ba/La and Nd/Hf ratios propound a two-stage petrogenetic process:(i)a depleted fore arc basalt(FAB)type tholeiitic melt parental to the crustal lithologies was extracted from the upwelling asthenospheric mantle at SSZ fore-arc extensional regime thereby rendering a refractory residual upper mantle;(ii)the crust and upper mantle of the SSZ fore arc were progressively refertilised by boninitic melts generated in response to subduction initiation and slab-dehydration.The vestiges of Tethyan oceanic lithosphere preserved in NHO represent an accreted intra-oceanic fore arc crust and upper mantle section which records a transitional geodynamic evolution in a SSZ regime marked by subduction initiation,fore arc extension and arc-continent accretion.
基金supported by the Zoology Key Subject of Henan Province.
文摘Objective： To screen and identify key genes differentially displayed in mouse fore stomach carcinoma, in order to elucidate the molecular mechanism underlying carcinogenesis. Methods： The animal models complied with each period of NIH mouse fore stomach carcinoma induced by N-Nitrososarcosineethylester （NSEE） were used in this study. The mice were euthanized on days 14, 28, 56, 77 and 84, respectively, after NSEE-piped treatment, and classified according to their pathologies. The differentially expressed genes were isolated from both normal and morbid tissues by mRNA differential display technique and screened by using Reverse Northern blot. Bioinformatics were employed to analyze the results observed. After identification, ten fragments were cloned and matched with GENEBANK database through homologous analysis. Results： One gene was found identical to splicing factor 3b subunit 1 （Sf3bl）, while seven fragments hold the homology of known cDNA clones. In contrast, other two fragments had extremely low identity to any genes registered in GENBANK databases. Conclusion： It is the first time to demonstrate in this study that splicing factor3b, subunitl （Sf3bl） is related to mouse fore stomach carcinoma. Furthermore, ESC-3 and ESC-4 are suggested to contribute to the development of mouse fore stomach carcinoma, thus may be candidates of new targets of oncogenes.
基金This work was supported in part by the National Key R&D Program of China under Grant 2017YFB1201003.
文摘This paper investigates characteristics of ironless permanent magnet linear synchronous motor(PMLSM)based on Halbach array used for medium-speed(200km/h)maglev train.Long primary ironless coil is laid in the middle of track and the Halbach permanent magnet array is attached to the bottom of each bogie as a source of traction,U-shape electromagnets at the both sides of the train for levitation.Two dimensional analytical model of single-sided ironless PMLSM based on Halbach array is established,using linear overlay method,the no-load air gap magnetic field is calculated firstly,winding current density distribution is obtained for calculating the characteristics of thrust and normal force against power angle,including force characteristics with equal and unequal pole pitch,the influence of steel sleeper,etc.Besides,the mathematical model for this type motor is built by 3D finite element method,the traction characteristics of medium-speed maglev under maximum speed 200km/h are calculated.The characteristics of this type motor are satisfactory owing to there is no detent force in the motor and thrust force reach maximum meanwhile normal force can be eliminated.Calculation method is verified by comparing finite element results,experimental result on a 200kW type motor further validates the accuracy of calculation and some important conclusions are obtained.
文摘The significance and status of the teachers'professional development make the education system and the society pay more and more attentions.The article elaborates the internal contact of curriculum discourse and teachers'professional development from a few respects such as the rationality of curriculum discourse,the long-term nature of the teachers'professional development and many factors affecting the teachers'professional development.The article also analyzes the external and internal factors influencing Tibet foreign language teachers'professional development,and puts forward the corresponding countermeasures in the light of these problems.
基金This work was supported by Henan Technologies R & D Project (No. 0424420043) and Henan Zoology Key Subject.
文摘Objective： To find out the relationship of the expressions of proliferating cell nuclear antigen （proliferating cell nuclear antigen, PCNA）, alkaline phosphotase （alkaline phosphotase, AKP） and acid phosphotase （acid phosphotase, ACP） with the development of mouse fore stomach cancerization. Methods： The animal models, including the various stages during the development of NIH mouse fore stomach carcinoma, were made by N-Nitrososarcosineethylester （N-Nitrososarcosineethylester, NSEE）. The mice were sacrificed on the 14th, 28th, 42nd, 56th, 70th and 84th days respectively after mice were irrigated with NSEE. The fore stomach was taken out and dissected. The methods of histopathology, immunohistochemistry and isoenzyme electrophoresis were adopted to study the dynamic changes of cell shape and expression of PCNA, AKP and ACP. Results： On the 42nd and 56th days after NSEE treatment, the expression of PCNA increased gradually along with the cancerization. Comparing with the control, there were significant differences （P〈0.05）. On the 70th and 84th days, the expression of PCNA increased further （compared with the control P〈0.01）. The activity of AKP increased gradually along with the cancerization. On the 14th, 28th, 42nd and 56th days, there were significant differences （P〈0.05）; on the 70th and 84th days, the activity of AKP increased further （P〈0.01）. The activity of ACP also increased on the 14th, 28th, 42nd and 56th days, and there were significant differences on the 70th days （P〈0.05） and on the 84th days （P〈0.01） compared with the control. Conclusion： During the carcinogenesis of NIH mouse fore stomach, the expressions of PCNA, AKP and ACP increased gradually and were consisted with the changes of cell shapes.
