Prescribed fire is used in the Sudanian savanna-woodland of West Africa as a forest management tool. An experiment was carried out to assess the effects of season of burning, and different vertical probe positions on ...Prescribed fire is used in the Sudanian savanna-woodland of West Africa as a forest management tool. An experiment was carried out to assess the effects of season of burning, and different vertical probe positions on maximum fire temperature and temperature residence time above 60℃ which is considered lethal for plant tissues. Seasons of burning considered were： an early season fire set at the beginning of the dry season （beginning of December）, mid-season fire set at the peak of the dry season （mid-January）, and a late season fire at the end of the dry season （end of March）. The effects of these fires on the germination of buried seeds of three socio-economically valuable tree species were also examined. Results indicated significant differences in maximum fire temperature and residence time with respect to season of burning and vertical probe position （p 〈 0.001）. The highest and longest lasting temperatures were observed at 20 cm above ground during early fire and at the soil surface during mid-season and late fires. This, in turn, affected germination responses of seeds buried at different soil depths. Implications of these findings in the current management practices are discussed.展开更多
Green buildings should be sustainable, efficient, economical, and to improve the quality of life of users and nearby residents. Unfortunately, some architecture features fostered by energy and environmental certificat...Green buildings should be sustainable, efficient, economical, and to improve the quality of life of users and nearby residents. Unfortunately, some architecture features fostered by energy and environmental certifications do not comply with fire prevention codes. Several factors can influence a building＇s energy efficiency and fire safety, such as bigger or smaller glass areas, building material thermal inertia, and the use of sustainable solutions such as green roofs. In this work, a methodology for integrating energy efficiency and fire prevention in green buildings is presented. A case study comparing a full glass skin and a building with 40% window size is considered. Also, the methodology permits modifications for obtaining a safe and energy efficient building.展开更多
Solenopsis sp. is an important invader on upland arthropod of Eastern India. This study was conducted to evaluate the role of this insect as potential biocontrol agent against some major pests of rice. The ant populat...Solenopsis sp. is an important invader on upland arthropod of Eastern India. This study was conducted to evaluate the role of this insect as potential biocontrol agent against some major pests of rice. The ant populations were sampled before and during appearance of hibernating larva and pupa of rice yellow stem borer （YSB） Scirpophaga incertulas （Walk.） inside the rice plant. Species richness and diversity of other ant species were also assessed from YSB protected field with insecticides and the crop grown under natural biological control. The maximum value of Barger-Parker index （d = 0.245） indicated that fire ant constituted 24.55% of the total population. Besides, in natural as in agricultural ecosystems, interference between fire ants and mealy bug as well as aphids was also recorded in different altitudes of the Eastern Himalayas and found that the incidence of fire ants Solenopsis sp. decreased the abundance of borer pests, but in contrast it increased the hopper pests in the same ecological niche.展开更多
The Stratospheric Aerosol and Gas Experiment （SAGE） II aerosol extinction profiles at 1020 nm were used to study the distribution characteristics of stratospheric aerosols during the volcanically quiescent period of...The Stratospheric Aerosol and Gas Experiment （SAGE） II aerosol extinction profiles at 1020 nm were used to study the distribution characteristics of stratospheric aerosols during the volcanically quiescent period of 1998-2004. The stratospheric aerosol distributions exhibited hemispheric asymmetry between the Northern Hemisphere （NH） and the Southern Hemisphere （SH）. In the lower stratosphere below 20 km, the zonal averaged aerosol optical depths in the NH were higher than those of the corresponding SH; whereas at higher altitudes above 20 km, the optical depths in the SH-- except the equatorial region--were higher than those of the NH. At 0-10°N and 10-20°N, the stratospheric aerosol optical depth （SAOD） exhibited larger values in boreal winter and lower values in the spring and summer; at 0-10°S and 10-20°S, the SAOD presented small seasonal variations. At 30-40°N, the SAOD presented larger values in the boreal fall and winter and lower values in the spring and summer; while at 30-40°S, the SAOD exhibited larger values in the austral winter and early spring and lower values in the summer and fall. These characteristics can mainly be attributed to the seasonal cycle of the dynamic transport, and the effects of the buildup and breakdown of the polar vortex. At 50-60°S, the SAOD exhibited extremely high values during austral winter associated with the Antarctic polar vortex boundary; at 50-60°N, the SAOD also exhibited larger values during the boreal winter, but it was much less obvious than that of its southern counterpart.展开更多
基金supported by the Swedish International Development Cooperation Agency (Sida)
文摘Prescribed fire is used in the Sudanian savanna-woodland of West Africa as a forest management tool. An experiment was carried out to assess the effects of season of burning, and different vertical probe positions on maximum fire temperature and temperature residence time above 60℃ which is considered lethal for plant tissues. Seasons of burning considered were： an early season fire set at the beginning of the dry season （beginning of December）, mid-season fire set at the peak of the dry season （mid-January）, and a late season fire at the end of the dry season （end of March）. The effects of these fires on the germination of buried seeds of three socio-economically valuable tree species were also examined. Results indicated significant differences in maximum fire temperature and residence time with respect to season of burning and vertical probe position （p 〈 0.001）. The highest and longest lasting temperatures were observed at 20 cm above ground during early fire and at the soil surface during mid-season and late fires. This, in turn, affected germination responses of seeds buried at different soil depths. Implications of these findings in the current management practices are discussed.
文摘Green buildings should be sustainable, efficient, economical, and to improve the quality of life of users and nearby residents. Unfortunately, some architecture features fostered by energy and environmental certifications do not comply with fire prevention codes. Several factors can influence a building＇s energy efficiency and fire safety, such as bigger or smaller glass areas, building material thermal inertia, and the use of sustainable solutions such as green roofs. In this work, a methodology for integrating energy efficiency and fire prevention in green buildings is presented. A case study comparing a full glass skin and a building with 40% window size is considered. Also, the methodology permits modifications for obtaining a safe and energy efficient building.
文摘Solenopsis sp. is an important invader on upland arthropod of Eastern India. This study was conducted to evaluate the role of this insect as potential biocontrol agent against some major pests of rice. The ant populations were sampled before and during appearance of hibernating larva and pupa of rice yellow stem borer （YSB） Scirpophaga incertulas （Walk.） inside the rice plant. Species richness and diversity of other ant species were also assessed from YSB protected field with insecticides and the crop grown under natural biological control. The maximum value of Barger-Parker index （d = 0.245） indicated that fire ant constituted 24.55% of the total population. Besides, in natural as in agricultural ecosystems, interference between fire ants and mealy bug as well as aphids was also recorded in different altitudes of the Eastern Himalayas and found that the incidence of fire ants Solenopsis sp. decreased the abundance of borer pests, but in contrast it increased the hopper pests in the same ecological niche.
基金supported by the National Basic Research Program of China (Grant No. 2013CB955801)the National Natural Science Foundation of China (Grant No. 41275047)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA05100300)
文摘The Stratospheric Aerosol and Gas Experiment （SAGE） II aerosol extinction profiles at 1020 nm were used to study the distribution characteristics of stratospheric aerosols during the volcanically quiescent period of 1998-2004. The stratospheric aerosol distributions exhibited hemispheric asymmetry between the Northern Hemisphere （NH） and the Southern Hemisphere （SH）. In the lower stratosphere below 20 km, the zonal averaged aerosol optical depths in the NH were higher than those of the corresponding SH; whereas at higher altitudes above 20 km, the optical depths in the SH-- except the equatorial region--were higher than those of the NH. At 0-10°N and 10-20°N, the stratospheric aerosol optical depth （SAOD） exhibited larger values in boreal winter and lower values in the spring and summer; at 0-10°S and 10-20°S, the SAOD presented small seasonal variations. At 30-40°N, the SAOD presented larger values in the boreal fall and winter and lower values in the spring and summer; while at 30-40°S, the SAOD exhibited larger values in the austral winter and early spring and lower values in the summer and fall. These characteristics can mainly be attributed to the seasonal cycle of the dynamic transport, and the effects of the buildup and breakdown of the polar vortex. At 50-60°S, the SAOD exhibited extremely high values during austral winter associated with the Antarctic polar vortex boundary; at 50-60°N, the SAOD also exhibited larger values during the boreal winter, but it was much less obvious than that of its southern counterpart.
