Background Cotton crop is infested by numerous arthropod pests from sowing to harvesting,causing substantial direct and indirect yield losses.Knowledge of seasonal population trends and the relative occurrence of pest...Background Cotton crop is infested by numerous arthropod pests from sowing to harvesting,causing substantial direct and indirect yield losses.Knowledge of seasonal population trends and the relative occurrence of pests and their natural enemies is required to minimize the pest population and yield losses.In the current study,analysis of the seasonal population trend of pests and natural enemies and their relative occurrence on cultivars of three cotton species in Central India has been carried out.Results A higher number and diversity of sucking pests were observed during the vegetative cotton growth stage(60 days after sowing),declining as the crop matured.With the exception of cotton jassid(Amrasca biguttula biguttula Ishida),which caused significant crop damage mainly from August to September;populations of other sucking insects seldom reached economic threshold levels(ETL)throughout the studied period.The bollworm complex populations were minimal,except for the pink bollworm(Pectinophora gossypiella Saunders),which re-emerged as a menace to cotton crops during the cotton cropping season 2017–2018 due to resistance development against Bt-cotton.A reasonably good number of predatory arthropods,including coccinellids,lacewings,and spiders,were found actively preying on the arthropod pest complex of the cotton crop during the early vegetative growth stage.Linear regression indicates a significant relationship between green boll infestations and pink bollworm moths in pheromone traps.Multiple linear regression analyse showed mean weekly weather at one-or two-week lag periods had a significant impact on sucking pest population(cotton aphid,cotton jassid,cotton whitefly,and onion thrips)fluctuation.Gossypium hirsutum cultivars RCH 2 and DCH 32,and G.barbadense cultivar Suvin were found susceptible to cotton jassid and onion thrips.Phule Dhanvantary,an G.arboreum cotton cultivar,demonstrated the highest tolerance among all evaluated cultivars against all sucking pests.Conclusion These findings have important implications for pest management in cotton crops.Susceptible cultivars warrant more attention for plant protection measures,making them more input-intensive.The choice of appropriate cultivars can help minimize input costs,thereby increasing net returns for cotton farmers.展开更多
China’s manganese resources are usually associated with the valuable elements such as silver, lead, zinc, cobalt, nickel, scandium, etc which should be comprehensively recovered during the manganese beneficiation. A ...China’s manganese resources are usually associated with the valuable elements such as silver, lead, zinc, cobalt, nickel, scandium, etc which should be comprehensively recovered during the manganese beneficiation. A manganese ore from western China contains Mn 23.18%, Co 0.073%, Ni 0.21% and Sc 0.013%. The mineralogy composition of ore and the occurrence of associated elements of Sc, Co as well as Ni are studied in this paper. According to the results, the manganese minerals in this ore are mainly lithiophorite and a little secondary pyrolusite. The lithiophorite in this ore is rich in aluminum and actually it is the generic name for the multi-mineral aggregates mixed by silicon, aluminum and iron, which is quite different with the ordinary psilomelane. There is not any Sc, Ni or Co mineral in this ore and more than 98% of Sc, Ni and Ni exists in lithiophorite and pyrolusite. The distribution of Sc, Co and Ni in lithiophorite is further studied by EPMA and the results indicate that Sc and Co in lithiophorite is sparse and dispersed distribution while Ni usually distributes in the argillaceous lithiophorite and is local enrichment. Reduction-sulfuric acid leaching tests show that the dissolution of Sc and Co happens before lithiophorite dissolves; the dissolution rate of Sc and Co is almost the same, which is significantly higher than the dissolution rate of manganese. However, the dissolution rate of Ni is extremely low with the dissolution of manganse, which indicates that Ni is hard to dissolve and its dissolution rate obviously lags behind that of Mn, Sc and Co. The conclusion can be drawn that Sc and Co exist in the lithiophorite crystals as interface adsorption while Ni exists in the clay (kaolinite) mixed up with lithiophorite as interface adsorption. The conclusion indicates that Sc and Co can dissolve before the dissolution of manganese at a high dissolution rate in the hydrometallurgical process while Ni is also into the solution through desorption from the interface of clay but its dissolution rate is rather slow because of the insoluble nature of clay.展开更多
For long-term prediction of occurrence degree of tobacco aphid Myzus persicae （Sulzer）, Markov chain method was used to establish prediction model for occurrence degree of tobacco aphid. With 4 levels of occurrence ...For long-term prediction of occurrence degree of tobacco aphid Myzus persicae （Sulzer）, Markov chain method was used to establish prediction model for occurrence degree of tobacco aphid. With 4 levels of occurrence degree, Markov chain model was established based on the data in 1987-2004. The results indicated that the accuracy for total prediction in 2005-2007 and the back prediction in 1987-2004 reached 88.89% and 85.12%, respectively. The method is simple and feasible for long-term prediction of occurrence degree of tobacco aphid.展开更多
Shaxi porphyry Cu-Au deposit was one of the important discoveries of the exploration in the middle-lower reaches of Yangtze River in China in 1970s. Gold occurrence in the Shaxi porphyry copper-gold deposit (central (...Shaxi porphyry Cu-Au deposit was one of the important discoveries of the exploration in the middle-lower reaches of Yangtze River in China in 1970s. Gold occurrence in the Shaxi porphyry copper-gold deposit (central (Anhui) province, eastern China) was investigated by means of microscope analyses, EPMA and PIXE. Combined with geological and mineralogical methods, the characteristics of occurrence of gold in the large scale sulfide mineralization in this region were fully investigated. The results show that gold distributes in both chalcopyrite and pyrite as submicroscopic inclusions (less than 1 μm) . Au is positively correlated with As, Fe, S, Cu, Zn and Ti. The condition of gold transformation in thermal fluid system controlling deposition of Au in the region is probably the oxidation potential of the red sedimentary rocks of shale and fine grain sandstone which may be crucial as a geochemical barrier to the reducing fluid. This study lays foundation for the further research and exploration of the porphyry copper-gold deposit both theoretically and practically in the lower reaches of Yangtze region.展开更多
Whistler mode chorus waves are important electromagnetic emissions due to their dual roles in acceleration and loss processes of Earth's radiation belt electrons.A detailed global survey of lower-band chorus is pe...Whistler mode chorus waves are important electromagnetic emissions due to their dual roles in acceleration and loss processes of Earth's radiation belt electrons.A detailed global survey of lower-band chorus is performed using EMFISIS data from Van Allen Probes in near-equatorial orbits.In addition to the confirmation of the positive correlation of chorus wave intensities to geomagnetic activity and dayside-nightside distribution asymmetry of wave amplitude and occurrence probability,the analysis results find that in statistics lower-band chorus emissions exhibit higher wave occurrence rates and larger normalized peak wave frequencies in the magnetically northern hemisphere but somehow stronger peak wave intensities in the magnetically southern hemisphere.While overall the differences between the two magnetically hemispheric distributions tend to be not significant,it is important to establish the magnetically hemispheric distribution profiles of lowerband chorus with respect to L-shell,magnetic local time,and geomagnetic latitude for improved understanding of chorus-induced dynamics of radiation belt electrons.展开更多
Using variety of modern testing methods, the processing mineralogical characteristics for a lead and zinc oxide ore in Sichuan were studied systematically. The chemical analysis result shows that the lead and zinc oxi...Using variety of modern testing methods, the processing mineralogical characteristics for a lead and zinc oxide ore in Sichuan were studied systematically. The chemical analysis result shows that the lead and zinc oxide content exceeding the minimum industrial grade and iron ore, total iron content reaches a minimum industrial grade and associated with gold and silver; The mineralogical analysis result shows that lead and zinc mineral composition and configuration are very complexity. The zinc minerals and zinciferous minerals are sphalerite, hemimorphite, Smithsonite, Hydrozincite, zinc chlorite, limonite, zinc dolomite and zincocalcite; lead minerals and plumbiferous minerals are mainly galena, cerussite, anglesite, limonite and Coronadite; The minerals disseminated grain size are very fine and mineral dissemination characteristics are very complex ; expected theoretical recoveries for lead and zinc were 72% and 67% respectively. The results of this study provide basic data and theoretical basis for ore dressing.展开更多
Nigeria lies very close to the equator(hot country) at the west coast of Africa between latitude 4°-14°N and longitude 2°-15°E.The country is located at the northern end of eastern branch of west c...Nigeria lies very close to the equator(hot country) at the west coast of Africa between latitude 4°-14°N and longitude 2°-15°E.The country is located at the northern end of eastern branch of west coast of Africa rift system.Nigeria geological setting comprises broadly sedimentary formation and crystalline basement complex,which occur more or less in equal proportion all over the country.The sediment展开更多
A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the per...A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the performance of a pile foundation. Its prior distribution and updating distribution were deduced to follow Beta distributions. To calibrate the OPDP, a dynamic estimation model was established according to the relationships between prior mean and variance and updating mean and variance. Finally, a reliability-control method dealing with uncertainties arising from quality assurance inspection was formalized to judge whether all the bored piles from a site can be accepted. It is exemplified that the OPDP can be substantially improved when more definite prior information and sampling formation become available. For the example studied herein, the Bayesian estimator of updating variance for OPDP is reduced from 0.0037 to 0.0014 for the first inspection, from 0.0014 to 0.0009 for the second inspection, and with less uncertainty by incorporating experience information.展开更多
基金Funding support for the Crop Pest Surveillance and Advisory Project(CROPSAP)。
文摘Background Cotton crop is infested by numerous arthropod pests from sowing to harvesting,causing substantial direct and indirect yield losses.Knowledge of seasonal population trends and the relative occurrence of pests and their natural enemies is required to minimize the pest population and yield losses.In the current study,analysis of the seasonal population trend of pests and natural enemies and their relative occurrence on cultivars of three cotton species in Central India has been carried out.Results A higher number and diversity of sucking pests were observed during the vegetative cotton growth stage(60 days after sowing),declining as the crop matured.With the exception of cotton jassid(Amrasca biguttula biguttula Ishida),which caused significant crop damage mainly from August to September;populations of other sucking insects seldom reached economic threshold levels(ETL)throughout the studied period.The bollworm complex populations were minimal,except for the pink bollworm(Pectinophora gossypiella Saunders),which re-emerged as a menace to cotton crops during the cotton cropping season 2017–2018 due to resistance development against Bt-cotton.A reasonably good number of predatory arthropods,including coccinellids,lacewings,and spiders,were found actively preying on the arthropod pest complex of the cotton crop during the early vegetative growth stage.Linear regression indicates a significant relationship between green boll infestations and pink bollworm moths in pheromone traps.Multiple linear regression analyse showed mean weekly weather at one-or two-week lag periods had a significant impact on sucking pest population(cotton aphid,cotton jassid,cotton whitefly,and onion thrips)fluctuation.Gossypium hirsutum cultivars RCH 2 and DCH 32,and G.barbadense cultivar Suvin were found susceptible to cotton jassid and onion thrips.Phule Dhanvantary,an G.arboreum cotton cultivar,demonstrated the highest tolerance among all evaluated cultivars against all sucking pests.Conclusion These findings have important implications for pest management in cotton crops.Susceptible cultivars warrant more attention for plant protection measures,making them more input-intensive.The choice of appropriate cultivars can help minimize input costs,thereby increasing net returns for cotton farmers.
文摘China’s manganese resources are usually associated with the valuable elements such as silver, lead, zinc, cobalt, nickel, scandium, etc which should be comprehensively recovered during the manganese beneficiation. A manganese ore from western China contains Mn 23.18%, Co 0.073%, Ni 0.21% and Sc 0.013%. The mineralogy composition of ore and the occurrence of associated elements of Sc, Co as well as Ni are studied in this paper. According to the results, the manganese minerals in this ore are mainly lithiophorite and a little secondary pyrolusite. The lithiophorite in this ore is rich in aluminum and actually it is the generic name for the multi-mineral aggregates mixed by silicon, aluminum and iron, which is quite different with the ordinary psilomelane. There is not any Sc, Ni or Co mineral in this ore and more than 98% of Sc, Ni and Ni exists in lithiophorite and pyrolusite. The distribution of Sc, Co and Ni in lithiophorite is further studied by EPMA and the results indicate that Sc and Co in lithiophorite is sparse and dispersed distribution while Ni usually distributes in the argillaceous lithiophorite and is local enrichment. Reduction-sulfuric acid leaching tests show that the dissolution of Sc and Co happens before lithiophorite dissolves; the dissolution rate of Sc and Co is almost the same, which is significantly higher than the dissolution rate of manganese. However, the dissolution rate of Ni is extremely low with the dissolution of manganse, which indicates that Ni is hard to dissolve and its dissolution rate obviously lags behind that of Mn, Sc and Co. The conclusion can be drawn that Sc and Co exist in the lithiophorite crystals as interface adsorption while Ni exists in the clay (kaolinite) mixed up with lithiophorite as interface adsorption. The conclusion indicates that Sc and Co can dissolve before the dissolution of manganese at a high dissolution rate in the hydrometallurgical process while Ni is also into the solution through desorption from the interface of clay but its dissolution rate is rather slow because of the insoluble nature of clay.
基金Supported by Tobacco Monopoly Bureau of Shandong Province (KN90)
文摘For long-term prediction of occurrence degree of tobacco aphid Myzus persicae （Sulzer）, Markov chain method was used to establish prediction model for occurrence degree of tobacco aphid. With 4 levels of occurrence degree, Markov chain model was established based on the data in 1987-2004. The results indicated that the accuracy for total prediction in 2005-2007 and the back prediction in 1987-2004 reached 88.89% and 85.12%, respectively. The method is simple and feasible for long-term prediction of occurrence degree of tobacco aphid.
文摘Shaxi porphyry Cu-Au deposit was one of the important discoveries of the exploration in the middle-lower reaches of Yangtze River in China in 1970s. Gold occurrence in the Shaxi porphyry copper-gold deposit (central (Anhui) province, eastern China) was investigated by means of microscope analyses, EPMA and PIXE. Combined with geological and mineralogical methods, the characteristics of occurrence of gold in the large scale sulfide mineralization in this region were fully investigated. The results show that gold distributes in both chalcopyrite and pyrite as submicroscopic inclusions (less than 1 μm) . Au is positively correlated with As, Fe, S, Cu, Zn and Ti. The condition of gold transformation in thermal fluid system controlling deposition of Au in the region is probably the oxidation potential of the red sedimentary rocks of shale and fine grain sandstone which may be crucial as a geochemical barrier to the reducing fluid. This study lays foundation for the further research and exploration of the porphyry copper-gold deposit both theoretically and practically in the lower reaches of Yangtze region.
基金Supported by the National Natural Science Foundation of China(41674163,41574160)the Hubei Province Natural Science Excellent Youth Foundation(2016CFA044)。
文摘Whistler mode chorus waves are important electromagnetic emissions due to their dual roles in acceleration and loss processes of Earth's radiation belt electrons.A detailed global survey of lower-band chorus is performed using EMFISIS data from Van Allen Probes in near-equatorial orbits.In addition to the confirmation of the positive correlation of chorus wave intensities to geomagnetic activity and dayside-nightside distribution asymmetry of wave amplitude and occurrence probability,the analysis results find that in statistics lower-band chorus emissions exhibit higher wave occurrence rates and larger normalized peak wave frequencies in the magnetically northern hemisphere but somehow stronger peak wave intensities in the magnetically southern hemisphere.While overall the differences between the two magnetically hemispheric distributions tend to be not significant,it is important to establish the magnetically hemispheric distribution profiles of lowerband chorus with respect to L-shell,magnetic local time,and geomagnetic latitude for improved understanding of chorus-induced dynamics of radiation belt electrons.
文摘Using variety of modern testing methods, the processing mineralogical characteristics for a lead and zinc oxide ore in Sichuan were studied systematically. The chemical analysis result shows that the lead and zinc oxide content exceeding the minimum industrial grade and iron ore, total iron content reaches a minimum industrial grade and associated with gold and silver; The mineralogical analysis result shows that lead and zinc mineral composition and configuration are very complexity. The zinc minerals and zinciferous minerals are sphalerite, hemimorphite, Smithsonite, Hydrozincite, zinc chlorite, limonite, zinc dolomite and zincocalcite; lead minerals and plumbiferous minerals are mainly galena, cerussite, anglesite, limonite and Coronadite; The minerals disseminated grain size are very fine and mineral dissemination characteristics are very complex ; expected theoretical recoveries for lead and zinc were 72% and 67% respectively. The results of this study provide basic data and theoretical basis for ore dressing.
文摘Nigeria lies very close to the equator(hot country) at the west coast of Africa between latitude 4°-14°N and longitude 2°-15°E.The country is located at the northern end of eastern branch of west coast of Africa rift system.Nigeria geological setting comprises broadly sedimentary formation and crystalline basement complex,which occur more or less in equal proportion all over the country.The sediment
基金Project(51278216) supported by the National Natural Science Foundation of ChinaProject(2013BS010) supported by Henan University of Technology Fund for High-level Talent,China
文摘A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the performance of a pile foundation. Its prior distribution and updating distribution were deduced to follow Beta distributions. To calibrate the OPDP, a dynamic estimation model was established according to the relationships between prior mean and variance and updating mean and variance. Finally, a reliability-control method dealing with uncertainties arising from quality assurance inspection was formalized to judge whether all the bored piles from a site can be accepted. It is exemplified that the OPDP can be substantially improved when more definite prior information and sampling formation become available. For the example studied herein, the Bayesian estimator of updating variance for OPDP is reduced from 0.0037 to 0.0014 for the first inspection, from 0.0014 to 0.0009 for the second inspection, and with less uncertainty by incorporating experience information.
