Doppler velocities observed by the Rankin Inlet （RKN） PolarDARN radar are assessed with a focus on data in the beams oriented roughly along the magnetic meridian. Hourly scatter plots for every month are built. They...Doppler velocities observed by the Rankin Inlet （RKN） PolarDARN radar are assessed with a focus on data in the beams oriented roughly along the magnetic meridian. Hourly scatter plots for every month are built. They are shown to vary widely, with median values showing very clear magnetic local time variation with maximum magnitude during pre-noon and pre-midnight hours. The histograms contain a significant amount of very small velocity data that dominates at farther ranges and during the daytime. Near noon data show generally antisunward flows but at large ranges/magnetic latitudes and very close to noon, sunward flows occur for periods of positive IMF Bz. The reverse flows are stronger during spring equinox. The velocity magnitude was found to depend linearly on the IMF Be and interplanetary electric field. Velocities are often found to be smaller than those expected from the statistical convection model of Ruohoniemi and Greenwald -1996.展开更多
Suppose that X is a right process which is associated with a semi-Dirichlet form （ε, D（ε）） on L2（E; m）. Let J be the jumping measure of （ε, D（ε）） satisfying J（E x E- d） 〈 ∞. Let u E D（ε）b ：= D（...Suppose that X is a right process which is associated with a semi-Dirichlet form （ε, D（ε）） on L2（E; m）. Let J be the jumping measure of （ε, D（ε）） satisfying J（E x E- d） 〈 ∞. Let u E D（ε）b ：= D（ε） N L（E; m）, we have the following Pukushima＇s decomposition u（Xt）-u（X0） --- Mut ＋ Nut. Define Pu f（x） = Ex[eNT f（Xt）]. Let Qu（f,g） = ε（f,g）＋ε（u, fg） for f, g E D（ε）b. In the first part, under some assumptions we show that （Qu, D（ε）b） is lower semi-bounded if and only if there exists a constant a0 〉 0 such that /Put/2 ≤eaot for every t 〉 0. If one of these assertions holds, then （Put〉0is strongly continuous on L2（E;m）. If X is equipped with a differential structure, then under some other assumptions, these conclusions remain valid without assuming J（E x E - d） 〈 ∞. Some examples are also given in this part. Let At be a local continuous additive functional with zero quadratic variation. In the second part, we get the representation of At and give two sufficient conditions for PAf（x） = Ex[eAtf（Xt）] to be strongly continuous.展开更多
In this paper, we propose a product image retrieval method based on the object contour corners, image texture and color. The product image mainly highlights the object and its background is very simple. According to t...In this paper, we propose a product image retrieval method based on the object contour corners, image texture and color. The product image mainly highlights the object and its background is very simple. According to these characteristics, we represent the object using its contour, and detect the corners of contour to reduce the number of pixels. Every corner is described using its approximate curvature based on distance. In addition, the Block Difference of Inverse Probabilities (BDIP) and Block Variation of Local Correlation (BVLC) texture features and color moment are extracted from image's HIS color space. Finally, dynamic time warping method is used to match features with different length. In order to demonstrate the effect of the proposed method, we carry out experiments in Mi-crosoft product image database, and compare it with other feature descriptors. The retrieval precision and recall curves show that our method is feasible.展开更多
In the Argentine Puna,a particular type of wetlands called vegas are considered unique,as they are the main biodiversity hotspots in this arid high-elevation environment.Also,they provide essential ecosystem services....In the Argentine Puna,a particular type of wetlands called vegas are considered unique,as they are the main biodiversity hotspots in this arid high-elevation environment.Also,they provide essential ecosystem services.Despite their ecological significance,these ecosystems remain poorly studied.Particularly soil mesofauna,which play critical roles in nutrient cycling and organic matter dynamics,remain to be explored.We investigated the composition,abundance,and richness of taxa and feeding guilds of soil mesofauna communities across 10 vegas.These wetlands were distributed along an environmental gradient,in an elevation range of 3323-4748 m a.s.l.,where we analysed soil properties and plant communities.We collected a total of 5239 invertebrates,from which Acari was the most abundant group,followed by Collembola.Regarding feeding guilds,detritivores and predators dominated soil mesofauna communities.Variability in taxa abundance and richness was strongly influenced by local soil properties,such as organic matter,carbon-to-nitrogen ratio,and phosphorus content,as well as plant community attributes,particularly cushion plant cover.However,no soil or vegetation variables explained the differences in taxa identity across vegas.These findings highlight the critical role of local heterogeneity in shaping soil mesofauna communities and provide the first insights into these understudied ecosystems.展开更多
In the past twenty years,great achievements have been made by many researchers in the studies of chaotic behavior and local entropy theory of dynamical systems.Most of the results have been generalized to the relative...In the past twenty years,great achievements have been made by many researchers in the studies of chaotic behavior and local entropy theory of dynamical systems.Most of the results have been generalized to the relative case in the sense of a given factor map.In this survey we offer an overview of these developments.展开更多
基金supported by NSERC Discovery grant to AVK and the University of Saskatchewan graduate stipend to MG
文摘Doppler velocities observed by the Rankin Inlet （RKN） PolarDARN radar are assessed with a focus on data in the beams oriented roughly along the magnetic meridian. Hourly scatter plots for every month are built. They are shown to vary widely, with median values showing very clear magnetic local time variation with maximum magnitude during pre-noon and pre-midnight hours. The histograms contain a significant amount of very small velocity data that dominates at farther ranges and during the daytime. Near noon data show generally antisunward flows but at large ranges/magnetic latitudes and very close to noon, sunward flows occur for periods of positive IMF Bz. The reverse flows are stronger during spring equinox. The velocity magnitude was found to depend linearly on the IMF Be and interplanetary electric field. Velocities are often found to be smaller than those expected from the statistical convection model of Ruohoniemi and Greenwald -1996.
基金supported by NSFC(11201102,11326169,11361021)Natural Science Foundation of Hainan Province(112002,113007)
文摘Suppose that X is a right process which is associated with a semi-Dirichlet form （ε, D（ε）） on L2（E; m）. Let J be the jumping measure of （ε, D（ε）） satisfying J（E x E- d） 〈 ∞. Let u E D（ε）b ：= D（ε） N L（E; m）, we have the following Pukushima＇s decomposition u（Xt）-u（X0） --- Mut ＋ Nut. Define Pu f（x） = Ex[eNT f（Xt）]. Let Qu（f,g） = ε（f,g）＋ε（u, fg） for f, g E D（ε）b. In the first part, under some assumptions we show that （Qu, D（ε）b） is lower semi-bounded if and only if there exists a constant a0 〉 0 such that /Put/2 ≤eaot for every t 〉 0. If one of these assertions holds, then （Put〉0is strongly continuous on L2（E;m）. If X is equipped with a differential structure, then under some other assumptions, these conclusions remain valid without assuming J（E x E - d） 〈 ∞. Some examples are also given in this part. Let At be a local continuous additive functional with zero quadratic variation. In the second part, we get the representation of At and give two sufficient conditions for PAf（x） = Ex[eAtf（Xt）] to be strongly continuous.
基金Supported by the Major Program of National Natural Science Foundation of China (No. 70890080 and No. 70890083)
文摘In this paper, we propose a product image retrieval method based on the object contour corners, image texture and color. The product image mainly highlights the object and its background is very simple. According to these characteristics, we represent the object using its contour, and detect the corners of contour to reduce the number of pixels. Every corner is described using its approximate curvature based on distance. In addition, the Block Difference of Inverse Probabilities (BDIP) and Block Variation of Local Correlation (BVLC) texture features and color moment are extracted from image's HIS color space. Finally, dynamic time warping method is used to match features with different length. In order to demonstrate the effect of the proposed method, we carry out experiments in Mi-crosoft product image database, and compare it with other feature descriptors. The retrieval precision and recall curves show that our method is feasible.
基金supported by FONCYT grants(PICT 2016-2173,PICT 2018-04228).
文摘In the Argentine Puna,a particular type of wetlands called vegas are considered unique,as they are the main biodiversity hotspots in this arid high-elevation environment.Also,they provide essential ecosystem services.Despite their ecological significance,these ecosystems remain poorly studied.Particularly soil mesofauna,which play critical roles in nutrient cycling and organic matter dynamics,remain to be explored.We investigated the composition,abundance,and richness of taxa and feeding guilds of soil mesofauna communities across 10 vegas.These wetlands were distributed along an environmental gradient,in an elevation range of 3323-4748 m a.s.l.,where we analysed soil properties and plant communities.We collected a total of 5239 invertebrates,from which Acari was the most abundant group,followed by Collembola.Regarding feeding guilds,detritivores and predators dominated soil mesofauna communities.Variability in taxa abundance and richness was strongly influenced by local soil properties,such as organic matter,carbon-to-nitrogen ratio,and phosphorus content,as well as plant community attributes,particularly cushion plant cover.However,no soil or vegetation variables explained the differences in taxa identity across vegas.These findings highlight the critical role of local heterogeneity in shaping soil mesofauna communities and provide the first insights into these understudied ecosystems.
基金supported by Foundation for the Authors of National Excellent Doctoral Dissertation of China (Grant No.201018)National Natural Science Foundation of China (Grant No. 10801035)Ministry of Education of China (Grant No. 200802461004)
文摘In the past twenty years,great achievements have been made by many researchers in the studies of chaotic behavior and local entropy theory of dynamical systems.Most of the results have been generalized to the relative case in the sense of a given factor map.In this survey we offer an overview of these developments.
