Swidden agriculture is by far the dominant land use system in the uplands of Southeast Asia （SEA）, as well as other tropical regions, which plays an important role in the implementation of Reducing Emissions from De...Swidden agriculture is by far the dominant land use system in the uplands of Southeast Asia （SEA）, as well as other tropical regions, which plays an important role in the implementation of Reducing Emissions from Deforestation and Forest Degradation （REDD） of United Nations. To our knowledge, the long-term inter-annual area of newly burned plots （NBP） of swidden agriculture in mainland Southeast Asia is still not available, let alone in the whole tropics. With the strengthening regional geo-economic cooperation in SEA, swidden agriculture has experienced and/or is still experiencing extensive and drastic transformations into other diverse market-oriented land use types since the 1990s. In this study, high-level surface reflectance products of Landsat 4151718 family sensors including Thematic Mapper （TM）, Enhanced Thematic Mapper Plus （ETM＋） and Operational Land Imager （OLI） acquired in March, April and May of each year between 1988 and 2016 were firstly utilized to detect and monitor the extent and area of NBP of swidden agriculture with multiple thresholds of four commonly-used vegetation indices, namely the Normalized Difference Vegetation Index （NDVI）, Normalized Difference Moisture Index （NDMI）, Normalized Burn Ratio （NBR） and Soil Adjusted Vegetation Index （SAVI）, in combination with local phenological features of swid- dening and topographical data. The results showed that： （1） an annual average of 6.08×104 km2 of NBP of swidden agriculture, or 3.15% of the total land area of MSEA, were estimated in the past nearly three decades. （2） Annual NBP were primarily distributed in four major geomorphic units including the Central Range of Hills, Northern Mountainous Region, West- ern Myanmar Hills, and Annamite Chain. （3） A decadal average analysis indicated that the NBP of swidden agriculture opened year by year declined as a whole, especially after 2010, merely with an average of 5.23×104 km2. （4） The top ten provincial administrative units in Cambodia, Laos, Myanmar, Thailand and Vietnam, which consistently accounted for over 90% of the newly opened swiddens of each country, showed distinct fluctuations in usingslash-and-burn practices in the last decades. The Landsat-based （30 m） reconstructed 29-year longitudinal updated maps （including extent and area） of the NBP of swidden agri- culture may contribute to REDD and local livelihood related studies in Continental Southeast Asia. Our study further demonstrated that the multiple vegetative indices thresholds approach holds great potential in detecting swidden agriculture in tropical mountainous regions.展开更多
This letter analyzes the reasons why the known Neural Back Promulgation (NBP)network learning algorithm has slower speed and greater sample error. Based on the analysis and experiment, the training group descending En...This letter analyzes the reasons why the known Neural Back Promulgation (NBP)network learning algorithm has slower speed and greater sample error. Based on the analysis and experiment, the training group descending Enhanced Combination Algorithm (ECA) is proposed.The analysis of the generalized property and sample error shows that the ECA can heighten the study speed and reduce individual error.展开更多
We report the surface electronic structure of niobium phosphide NbP single crystal on （001） surface by vacuum ultraviolet angle-resolved photoemission spectroscopy. Combining with our first principle calculations, w...We report the surface electronic structure of niobium phosphide NbP single crystal on （001） surface by vacuum ultraviolet angle-resolved photoemission spectroscopy. Combining with our first principle calculations, we identify the existence of the Fermi arcs originated from topological surface states. Furthermore, the surface states exhibit circular dichroism pattern, which may correlate with its non-trivial spin texture. Our results provide critical evidence for the existence of the Weyl Fermions in NbP, which lays the foundation for further research.展开更多
Objective: To explore the effect of NBP on the serum inflammatory cytokines, oxidative stress, and NF in patients with acute cerebral infarction (ACI). Methods: A total of 118 patients with ACI who were admitted in ou...Objective: To explore the effect of NBP on the serum inflammatory cytokines, oxidative stress, and NF in patients with acute cerebral infarction (ACI). Methods: A total of 118 patients with ACI who were admitted in our hospital from October 2016 to September 2017 were included in the study and randomized into the observation group and the control group, with 59 cases in each group. The patients in the control group were given blood pressure control, blood sugar control, micro-circulation improvement, anti-platelet aggregation, nerve nourishing, and lipid regulation. On the above basis, the patients in the observation group were given intravenous injection of NBP sodium chloride injection. The patients in the two groups were treated for 14 d. The morning fasting venous blood before treatment, 7 d and 14 d after treatment in the two groups was collected, and centrifuged for the serum. And IL-6, TFN-α, hs-CRP, SOD, MDA, NSE, VEGF, BDNF, and bFGF were measured. Results: 7 d and 14 d after treatment, the serum IL-6, TFN-α and hs-CRP in the observation group were significantly lower than those in the control group. Besides, 7 d and 14 d after treatment, the serum SOD in the observation group was significantly higher than that in the control group, while MDA was significantly lower than that in the control group. The serum NSE 7 d and 14 d after treatment in the observation group was significantly lower than that in the control group, while VEGF, BDNF, and bFGF were significantly higher than those in the control group. Conclusions: NBP in the treatment of ACI can down regulate the expression of inflammatory cytokines to play an anti-inflammatory effect, increase the antioxidant ability to remove OFR, improve the neurocyte metabolism, and effectively play the nerve protecting and prognosis improvement role.展开更多
In this study, we used the crystal structure search method and first-principles calculations to systematically explore the highpressure phase diagrams of the TaAs family （NbP, NbAs, TaP, and TaAs）. Our calculation r...In this study, we used the crystal structure search method and first-principles calculations to systematically explore the highpressure phase diagrams of the TaAs family （NbP, NbAs, TaP, and TaAs）. Our calculation results show that NbAs and TaAs have similar phase diagrams, the same structural phase transition sequence I41md→Pδm2→}P21/c→Pm3m, and slightly different transition pressures. The phase transition sequence of NbP and TaP differs somewhat from that of NbAs and TaAs, in which new structures emerge, such as the Cmcm structure in NbP and the Pmmn structure in TaP. Interestingly, we found that in the electronic structure of the high-pressure phase Pδm2-NbAs, there are coexisting Weyl points and triple degenerate points, similar to those found in high-pressure Pδm2-TaAs.展开更多
基金National Natural Science Foundation of China,No.41301090
文摘Swidden agriculture is by far the dominant land use system in the uplands of Southeast Asia （SEA）, as well as other tropical regions, which plays an important role in the implementation of Reducing Emissions from Deforestation and Forest Degradation （REDD） of United Nations. To our knowledge, the long-term inter-annual area of newly burned plots （NBP） of swidden agriculture in mainland Southeast Asia is still not available, let alone in the whole tropics. With the strengthening regional geo-economic cooperation in SEA, swidden agriculture has experienced and/or is still experiencing extensive and drastic transformations into other diverse market-oriented land use types since the 1990s. In this study, high-level surface reflectance products of Landsat 4151718 family sensors including Thematic Mapper （TM）, Enhanced Thematic Mapper Plus （ETM＋） and Operational Land Imager （OLI） acquired in March, April and May of each year between 1988 and 2016 were firstly utilized to detect and monitor the extent and area of NBP of swidden agriculture with multiple thresholds of four commonly-used vegetation indices, namely the Normalized Difference Vegetation Index （NDVI）, Normalized Difference Moisture Index （NDMI）, Normalized Burn Ratio （NBR） and Soil Adjusted Vegetation Index （SAVI）, in combination with local phenological features of swid- dening and topographical data. The results showed that： （1） an annual average of 6.08×104 km2 of NBP of swidden agriculture, or 3.15% of the total land area of MSEA, were estimated in the past nearly three decades. （2） Annual NBP were primarily distributed in four major geomorphic units including the Central Range of Hills, Northern Mountainous Region, West- ern Myanmar Hills, and Annamite Chain. （3） A decadal average analysis indicated that the NBP of swidden agriculture opened year by year declined as a whole, especially after 2010, merely with an average of 5.23×104 km2. （4） The top ten provincial administrative units in Cambodia, Laos, Myanmar, Thailand and Vietnam, which consistently accounted for over 90% of the newly opened swiddens of each country, showed distinct fluctuations in usingslash-and-burn practices in the last decades. The Landsat-based （30 m） reconstructed 29-year longitudinal updated maps （including extent and area） of the NBP of swidden agri- culture may contribute to REDD and local livelihood related studies in Continental Southeast Asia. Our study further demonstrated that the multiple vegetative indices thresholds approach holds great potential in detecting swidden agriculture in tropical mountainous regions.
基金the National Defense Research item "Data fusion" of Tenth Five-Year Plan 102010203
文摘This letter analyzes the reasons why the known Neural Back Promulgation (NBP)network learning algorithm has slower speed and greater sample error. Based on the analysis and experiment, the training group descending Enhanced Combination Algorithm (ECA) is proposed.The analysis of the generalized property and sample error shows that the ECA can heighten the study speed and reduce individual error.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174124,11274068,11374137,11421404 and 13ZR1451700the National Basic Research Program of China(973 Program)under Grant No 2012CB921402
文摘We report the surface electronic structure of niobium phosphide NbP single crystal on （001） surface by vacuum ultraviolet angle-resolved photoemission spectroscopy. Combining with our first principle calculations, we identify the existence of the Fermi arcs originated from topological surface states. Furthermore, the surface states exhibit circular dichroism pattern, which may correlate with its non-trivial spin texture. Our results provide critical evidence for the existence of the Weyl Fermions in NbP, which lays the foundation for further research.
文摘Objective: To explore the effect of NBP on the serum inflammatory cytokines, oxidative stress, and NF in patients with acute cerebral infarction (ACI). Methods: A total of 118 patients with ACI who were admitted in our hospital from October 2016 to September 2017 were included in the study and randomized into the observation group and the control group, with 59 cases in each group. The patients in the control group were given blood pressure control, blood sugar control, micro-circulation improvement, anti-platelet aggregation, nerve nourishing, and lipid regulation. On the above basis, the patients in the observation group were given intravenous injection of NBP sodium chloride injection. The patients in the two groups were treated for 14 d. The morning fasting venous blood before treatment, 7 d and 14 d after treatment in the two groups was collected, and centrifuged for the serum. And IL-6, TFN-α, hs-CRP, SOD, MDA, NSE, VEGF, BDNF, and bFGF were measured. Results: 7 d and 14 d after treatment, the serum IL-6, TFN-α and hs-CRP in the observation group were significantly lower than those in the control group. Besides, 7 d and 14 d after treatment, the serum SOD in the observation group was significantly higher than that in the control group, while MDA was significantly lower than that in the control group. The serum NSE 7 d and 14 d after treatment in the observation group was significantly lower than that in the control group, while VEGF, BDNF, and bFGF were significantly higher than those in the control group. Conclusions: NBP in the treatment of ACI can down regulate the expression of inflammatory cytokines to play an anti-inflammatory effect, increase the antioxidant ability to remove OFR, improve the neurocyte metabolism, and effectively play the nerve protecting and prognosis improvement role.
基金supported by the National Key R&D Program of China(Grant No.2016YFA0300404)the National Key Projects for Basic Research in China(Grant No.2015CB921202)+4 种基金the National Natural Science Foundation of China(Grant Nos.11574133,and 51372112)the Natural Science Foundation Jiangsu Province(Grant No.BK20150012)the Science Challenge Project(Grant No.TZ2016001)the Fundamental Research Funds for the Central UniversitiesSpecial Program for Applied Research on Super Computation of the National Natural Science FoundationGuangdong Joint Fund
文摘In this study, we used the crystal structure search method and first-principles calculations to systematically explore the highpressure phase diagrams of the TaAs family （NbP, NbAs, TaP, and TaAs）. Our calculation results show that NbAs and TaAs have similar phase diagrams, the same structural phase transition sequence I41md→Pδm2→}P21/c→Pm3m, and slightly different transition pressures. The phase transition sequence of NbP and TaP differs somewhat from that of NbAs and TaAs, in which new structures emerge, such as the Cmcm structure in NbP and the Pmmn structure in TaP. Interestingly, we found that in the electronic structure of the high-pressure phase Pδm2-NbAs, there are coexisting Weyl points and triple degenerate points, similar to those found in high-pressure Pδm2-TaAs.
