The media industry plays a central role in the emergence of a politically, socially, and economically conscious citizenry. This role has elevated the industry as a major stakeholder in the political, socio-cultural, a...The media industry plays a central role in the emergence of a politically, socially, and economically conscious citizenry. This role has elevated the industry as a major stakeholder in the political, socio-cultural, and economic development of the people. This essential role, however, has come under serious threat following the emergence of the Digital Age, changing social trends, and a global economy that is in distress. This is the main reason this paper investigates the survival strategies adopted by the US print media industry to deal with the decline and see how the Nigerian print media industry that is facing similar decline can benefit from the strategies. The method of study is qualitative. We gathered data through in-depth interviews and on-site observation of the operations of the selected media organizations. We also reviewed literature provided by the media firms and the ones that are already in the public domain. Our findings confirm recent projections that the American and Nigerian media industries are truly facing economics of decline and that the Nigerian industry is worst hit. The study identified some of the strategies adopted by the American print media industry to deal with the economic recession to include introduction of online editions, use of pay wall, free online views, Search Engine Optimization, Micro-funding, etc. After thorough interrogation of the literature and results, we conclude that the Nigerian print media industry could apply similar strategies used in the US to address its own negative economic situation. We also recommend an upgrade in the media training curricula to address some of these concerns effectively leading to the emergence of "Media Entrepreneurship" as a course in Communication/Media Departments in Nigerian universities.展开更多
This study was conducted in Aniocha South Local Government Area of Delta State. The major objective is to ascertain the forest dependent survival strategies of rural women in Aniocha South Local Government Area of Del...This study was conducted in Aniocha South Local Government Area of Delta State. The major objective is to ascertain the forest dependent survival strategies of rural women in Aniocha South Local Government Area of Delta State. The specific objectives are to ascertain the socio- economic characteristics of the women, find out the forest based activities of the women, identify what they do with products collected from the forest, establish how much income they make from such products weekly and identify the challenges of these women in exploiting forest for survival. Ten villages were selected and from the selected communities, 15 women were randomly selected in each community to give 150 respondents. From the result of the survey about 96.0% of the respondents had household sizes of between 6-10 persons. Women collect many forest products which include seeds, herbs, honey, mushroom, fuel wood, snails, stimulants, bitter kola, pear, raffia leaves (fronds), edible worms, wrapping leaves, spices, bush mango, locust beans, wild fruits, leaves, fuel wood, snails, mushrooms and fruits. Some of the forest products are used for income generation only, some for household use, while others are used for both income generation and household use. The major constraint is the decline in the availability of forest products as a result of deforestation, over exploitation, bush burning and long distance to available forests. The study shows that forest products play a significant role in improving the livelihood of rural people. Rural development and future forest conservation strategies and interventions should pay attention to the contribution of forest products to people's livelihood and environmental sustainability.展开更多
Background:Great diversity exists in the parenting pattern of altricial birds,which has long been considered as an adaptive response to specific environmental conditions but not to their life-history style.Methods:We ...Background:Great diversity exists in the parenting pattern of altricial birds,which has long been considered as an adaptive response to specific environmental conditions but not to their life-history style.Methods:We examined the egg-laying and nestling-raising pattern of the Grey-backed Shrike(Lanius tephronotus)that breeds only once a year on the Tibetan Plateau.We compared the dietary composition to that of its sympatric competitor,the Brown-cheeked Laughing Thrush(Trochalopteron henrici)that breeds twice a year.Results:Female Grey-backed Shrikes produced a fixed clutch size of five,with increasing egg size by their laying sequence.The last offspring in the brood is disadvantageous in the size hierarchy because it hatches later.However,they had the largest fledgling body mass.These findings indicate that Grey-backed Shrikes adopt the brood survival strategy in both the egg and nestling phases.Moreover,males and females exhibit no sexual division in providing parental care as they made an equal contribution to the total amount of food delivered to their brood.This parenting pattern of Grey-backed Shrikes,as well as their dietary items,differ significantly from those of the Brown-cheeked Laughing Thrush.Conclusions:We suggest that the differentiation in life-history style between sympatric competitors,rather than a behavioral response to specific environmental conditions,plays a decisive role in driving avian parenting strategy diversification.展开更多
Objective To investigate influence of immunosuppression strategy optimization on outcomes of renal transplant recipients in the last decades. Methods Data from 404 renal transplant recipients from Jan. 1st,2001 to Dec...Objective To investigate influence of immunosuppression strategy optimization on outcomes of renal transplant recipients in the last decades. Methods Data from 404 renal transplant recipients from Jan. 1st,2001 to Dec. 31st,2010 were analyzed retrospectively. The pa-展开更多
Drought is one of the most significant natural disasters in the arid and semi-arid areas of China.Populations or plant organs often differ in their responses to drought and other adversities at different growth stages...Drought is one of the most significant natural disasters in the arid and semi-arid areas of China.Populations or plant organs often differ in their responses to drought and other adversities at different growth stages.At present,little is known about the size-and leaf age-dependent differences in the mechanisms of shrub-related drought resistance in the deserts of China.Here,we evaluated the photosynthetic and physiological responses of Artemisia ordosica Krasch.to drought stress using a field experiment in Mu Us Sandy Land,Ningxia Hui Autonomous Region,China in 2018.Rainfall was manipulated by installing outdoor shelters,with four rainfall treatments applied to 12 plots(5 m×5 m).There were four rainfall levels,including a control and rainfall reductions of 30%,50%and 70%,each with three replications.Taking individual crown size as the dividing basis,we measured the responses of A.ordosica photosynthetic and physiological responses to drought at different growth stages,i.e.,large-sized(>0.5 m^(2))and small-sized(≤0.5 m^(2))plants.The leaves of A.ordosica were divided into old leaves and young leaves for separate measurement.Results showed that:(1)under drought stress,the transfer efficiency of light energy captured by antenna pigments to the photosystem II(PSII)reaction center decreased,and the heat dissipation capacity increased simultaneously.To resist the photosynthetic system damage caused by drought,A.ordosica enhanced its free radical scavenging capacity by activating its antioxidant enzyme system;and(2)growth stage and leaf age had effects on the reaction of the photosynthetic system to drought.Small A.ordosica plants could not withstand severe drought stress(70%rainfall reduction),whereas large A.ordosica individuals could absorb deep soil water to ensure their survival in severe drought stressed condition.Under 30%and 50%rainfall reduction conditions,young leaves had a greater ability to resist drought than old leaves,whereas the latter were more resistant to severe drought stress.The response of A.ordosica photosynthetic system reflected the trade-off at different growth stages and leaf ages of photosynthetic production under different degrees of drought.This study provides a more comprehensive and systematic perspective for understanding the drought resistance mechanisms of desert plants.展开更多
In the arid and semi-arid areas of China, rainfall and drought affect the growth and photosynthetic activities of plants.Gross primary productivity(GPP) is one of the most important indices that measure the photosynth...In the arid and semi-arid areas of China, rainfall and drought affect the growth and photosynthetic activities of plants.Gross primary productivity(GPP) is one of the most important indices that measure the photosynthetic ability of plants.This paper focused on the GPP of two representative grassland species(Stipa krylovii Roshev.and Allium polyrhizum Turcz.ex Regel) to demonstrate the effect of a temporal rainfall on the two species.Our research was conducted in a temperate grassland in New Barag Right Banner, Hulun Buir City, Inner Mongolia Autonomous Region of China, in a dry year 2015.We measured net ecosystem productivity(NEP) and ecosystem respiration flux(ER) using a transparent chamber system and monitored the photosynthetically active radiation(PAR), air and soil temperature and humidity simultaneously.Based on the measured values of NEP and ER, we calculated the GPP of the two species before and after the rainfall.The saturated GPP per aboveground biomass(GPPAGB) of A.polyrhizum remarkably increased from 0.033(±0.018) to 0.185(±0.055) μmol CO2/(gdw·s) by 5.6-fold and that of S.krylovii decreased from 0.068(±0.021) to 0.034(±0.011) μmol CO2/(gdw·s) by 0.5-fold on the 1st and 2nd d after a 9.1 mm rainfall event compared to the values before the rainfall at low temperatures below 35℃.However, on the 1st and 2nd d after the rainfall, both of the saturated GPPAGB values of S.krylovii and A.polyrhizum were significantly lower at high temperatures above 35℃(0.018(±0.007) and 0.110(±0.061) μmol CO2/(gdw·s), respectively) than at low temperatures below 35℃(0.034(±0.011) and 0.185(±0.055) μmol CO2/(gdw·s), respectively).The results showed that the GPP responses to the temporal rainfall differed between S.krylovii and A.polyrhizum and strongly negative influenced by temperature.The temporal rainfall seems to be more effective on the GPP of A.polyrhizum than S.krylovii.These differences might be related to the different physiological and structural features, the coexistence of the species and their species-specific survival strategies.展开更多
Laoya Cave is a long-term occupation site of Late Paleolithic humans in the Yunnan-Guizhou Plateau, southwest China, where abundant lithic, bone materials were recovered. Dating by the AMS technique showed a significa...Laoya Cave is a long-term occupation site of Late Paleolithic humans in the Yunnan-Guizhou Plateau, southwest China, where abundant lithic, bone materials were recovered. Dating by the AMS technique showed a significant depositional process during marine isotope stage(MIS) 3/2. In this study, the species spectrum was presented from the perspective of zooarchaeology and the mortality profile of large Cervidae was examined to help increase our understanding of the subsistence strategy of local people dealing with climate and environmental changes. The main part of the diet was focused on large Cervidae, and the dominance of Ungulates indicates effective management of the cave and local fauna. On the other hand, the mortality profiles of large Cervidae varied correspondingly with climate change. The evidence indicates a specialized hunting strategy that was also flexible, depending on the prevailing climate and environment.展开更多
Ticks are external parasitic arthropods that can transmit a variety of pathogens by sucking blood.Low-temperature tolerance is essential for ticks to survive during the cold winter.Exploring the protein regulation mec...Ticks are external parasitic arthropods that can transmit a variety of pathogens by sucking blood.Low-temperature tolerance is essential for ticks to survive during the cold winter.Exploring the protein regulation mechanism of low-temperature tolerance of Haemaphysalis longicornis could help to explain how ticks survive in winter.In this study,the quantitative proteomics of several tissues of H.longicornis exposed to low temperature were studied by data independent acquisition technology.Totals of 3699,3422,and 1958 proteins were identified in the salivary gland,midgut,and ovary,respectively.The proteins involved in energy metabolism,cell signal transduction,protein synthesis and repair,and cytoskeleton synthesis changed under low-temperature stress.The comprehensive analysis of the protein regulation of multiple tissues of female ticks exposed to low temperature showed that maintaining cell homeostasis,maintaining cell viability,and enhancing cell tolerance were the most important means for ticks to maintain vital signs under low temperature.The expression of proteins involved in and regulating the above cell activities was the key to the survival of ticks under low temperatures.Through the analysis of a large amount of data,we found that the expression levels of arylamine N-acetyltransferase,inositol polyphosphate multikinase,and dual-specificity phosphatase were up-regulated under low temperature.We speculated that they might have important significance in low-temperature tolerance.Then,we performed RNA interference on the mRNA of these 3 proteins,and the results showed that the ability of female ticks to tolerate low temperatures decreased significantly.展开更多
Deserts exhibit extreme climatic conditions.Small desert-dwelling vertebrates have physiological and behavioral adaptations to cope with these conditions,including the ability to seek shelter.We investigated the tempe...Deserts exhibit extreme climatic conditions.Small desert-dwelling vertebrates have physiological and behavioral adaptations to cope with these conditions,including the ability to seek shelter.We investigated the temperature(T)and relative humidity(RH)regulating properties of the soil cracks that characterize the extensive cracking-clay landscapes of arid Australia,and the extent of their use by 2 small marsupial species:fat-tailed and stripe-faced dunnarts(Sminthopsis crassicaudata and Sminthopsis macroura).We measured hourly(over 24-h periods)the T and RH of randomly-selected soil cracks compared to outside conditions,during 2 summers and 2 winters.We tracked 17 dunnarts(8 Sminthopsis crassicaudata and 9 Sminthopsis macroura)to quantify their use of cracks.Cracks consistently moderated microclimate,providing more stable conditions than available from non-crack points,which often displayed comparatively dramatic fluctuations in T and RH.Both dunnart species used crack shelters extensively.Cracks constitute important shelter for small animals during extreme conditions by providing a stable microclimate,which is typically cooler than outside conditions in summer and warmer in winter.Cracks likely play a fundamental sheltering role by sustaining the physiological needs of small mammal populations.Globally,cracking-clay areas are dominated by agricultural land uses,including livestock grazing.Management of these systems should focus not only on vegetation condition,but also on soil integrity,to maintain shelter resources for ground-dwelling fauna.展开更多
This paper investigates a cooperative strategy for protecting an aerial target.The problem is solved as a game among four players(a target,two defenders,and a missile).In this scenario,the target launches two defend...This paper investigates a cooperative strategy for protecting an aerial target.The problem is solved as a game among four players(a target,two defenders,and a missile).In this scenario,the target launches two defenders(defender-1 and defender-2)simultaneously,to establish a oneway cooperation system(OCS)against an attacking missile.A new optimal evasion strategy for the target is also derived.During the engagement,the target takes into account the reaction of the attacking missile,and guides defender-1 to the interception point by receiving information from defender-1.Depending on the control effort of the target,defender-2 can choose appropriate launch conditions and use very limited maneuvering capability to intercept the missile.For adversaries with first-order dynamics,simulation results show that the OCS allows two defenders to intercept the missile.During the engagement,even if one defender or communication channel is broken,the OCS still allows an interception to be made,thus increasing the target’s survivability.展开更多
文摘The media industry plays a central role in the emergence of a politically, socially, and economically conscious citizenry. This role has elevated the industry as a major stakeholder in the political, socio-cultural, and economic development of the people. This essential role, however, has come under serious threat following the emergence of the Digital Age, changing social trends, and a global economy that is in distress. This is the main reason this paper investigates the survival strategies adopted by the US print media industry to deal with the decline and see how the Nigerian print media industry that is facing similar decline can benefit from the strategies. The method of study is qualitative. We gathered data through in-depth interviews and on-site observation of the operations of the selected media organizations. We also reviewed literature provided by the media firms and the ones that are already in the public domain. Our findings confirm recent projections that the American and Nigerian media industries are truly facing economics of decline and that the Nigerian industry is worst hit. The study identified some of the strategies adopted by the American print media industry to deal with the economic recession to include introduction of online editions, use of pay wall, free online views, Search Engine Optimization, Micro-funding, etc. After thorough interrogation of the literature and results, we conclude that the Nigerian print media industry could apply similar strategies used in the US to address its own negative economic situation. We also recommend an upgrade in the media training curricula to address some of these concerns effectively leading to the emergence of "Media Entrepreneurship" as a course in Communication/Media Departments in Nigerian universities.
文摘This study was conducted in Aniocha South Local Government Area of Delta State. The major objective is to ascertain the forest dependent survival strategies of rural women in Aniocha South Local Government Area of Delta State. The specific objectives are to ascertain the socio- economic characteristics of the women, find out the forest based activities of the women, identify what they do with products collected from the forest, establish how much income they make from such products weekly and identify the challenges of these women in exploiting forest for survival. Ten villages were selected and from the selected communities, 15 women were randomly selected in each community to give 150 respondents. From the result of the survey about 96.0% of the respondents had household sizes of between 6-10 persons. Women collect many forest products which include seeds, herbs, honey, mushroom, fuel wood, snails, stimulants, bitter kola, pear, raffia leaves (fronds), edible worms, wrapping leaves, spices, bush mango, locust beans, wild fruits, leaves, fuel wood, snails, mushrooms and fruits. Some of the forest products are used for income generation only, some for household use, while others are used for both income generation and household use. The major constraint is the decline in the availability of forest products as a result of deforestation, over exploitation, bush burning and long distance to available forests. The study shows that forest products play a significant role in improving the livelihood of rural people. Rural development and future forest conservation strategies and interventions should pay attention to the contribution of forest products to people's livelihood and environmental sustainability.
基金Financial support was provided by the National Natural Sciences Foundation of China(Grant No.31672299,31572271 and 31772465)the Natural Science Foundation of Xizang Province of China(2016ZR-NY-05)。
文摘Background:Great diversity exists in the parenting pattern of altricial birds,which has long been considered as an adaptive response to specific environmental conditions but not to their life-history style.Methods:We examined the egg-laying and nestling-raising pattern of the Grey-backed Shrike(Lanius tephronotus)that breeds only once a year on the Tibetan Plateau.We compared the dietary composition to that of its sympatric competitor,the Brown-cheeked Laughing Thrush(Trochalopteron henrici)that breeds twice a year.Results:Female Grey-backed Shrikes produced a fixed clutch size of five,with increasing egg size by their laying sequence.The last offspring in the brood is disadvantageous in the size hierarchy because it hatches later.However,they had the largest fledgling body mass.These findings indicate that Grey-backed Shrikes adopt the brood survival strategy in both the egg and nestling phases.Moreover,males and females exhibit no sexual division in providing parental care as they made an equal contribution to the total amount of food delivered to their brood.This parenting pattern of Grey-backed Shrikes,as well as their dietary items,differ significantly from those of the Brown-cheeked Laughing Thrush.Conclusions:We suggest that the differentiation in life-history style between sympatric competitors,rather than a behavioral response to specific environmental conditions,plays a decisive role in driving avian parenting strategy diversification.
文摘Objective To investigate influence of immunosuppression strategy optimization on outcomes of renal transplant recipients in the last decades. Methods Data from 404 renal transplant recipients from Jan. 1st,2001 to Dec. 31st,2010 were analyzed retrospectively. The pa-
基金This research was supported by the National Natural Science Foundation of China(31700639)the National Key Research and Development Program of China(2018YFC0507102,2016YFC0500905).
文摘Drought is one of the most significant natural disasters in the arid and semi-arid areas of China.Populations or plant organs often differ in their responses to drought and other adversities at different growth stages.At present,little is known about the size-and leaf age-dependent differences in the mechanisms of shrub-related drought resistance in the deserts of China.Here,we evaluated the photosynthetic and physiological responses of Artemisia ordosica Krasch.to drought stress using a field experiment in Mu Us Sandy Land,Ningxia Hui Autonomous Region,China in 2018.Rainfall was manipulated by installing outdoor shelters,with four rainfall treatments applied to 12 plots(5 m×5 m).There were four rainfall levels,including a control and rainfall reductions of 30%,50%and 70%,each with three replications.Taking individual crown size as the dividing basis,we measured the responses of A.ordosica photosynthetic and physiological responses to drought at different growth stages,i.e.,large-sized(>0.5 m^(2))and small-sized(≤0.5 m^(2))plants.The leaves of A.ordosica were divided into old leaves and young leaves for separate measurement.Results showed that:(1)under drought stress,the transfer efficiency of light energy captured by antenna pigments to the photosystem II(PSII)reaction center decreased,and the heat dissipation capacity increased simultaneously.To resist the photosynthetic system damage caused by drought,A.ordosica enhanced its free radical scavenging capacity by activating its antioxidant enzyme system;and(2)growth stage and leaf age had effects on the reaction of the photosynthetic system to drought.Small A.ordosica plants could not withstand severe drought stress(70%rainfall reduction),whereas large A.ordosica individuals could absorb deep soil water to ensure their survival in severe drought stressed condition.Under 30%and 50%rainfall reduction conditions,young leaves had a greater ability to resist drought than old leaves,whereas the latter were more resistant to severe drought stress.The response of A.ordosica photosynthetic system reflected the trade-off at different growth stages and leaf ages of photosynthetic production under different degrees of drought.This study provides a more comprehensive and systematic perspective for understanding the drought resistance mechanisms of desert plants.
基金jointly supported by the National Natural Science Foundation of China (31470504, 31670455)the Grant-in-Aid for Scientific Research by the Japan Society for the Promotion of Science (grant 23405001)the National Key Research and Development Program of China (2016YFC0500908)
文摘In the arid and semi-arid areas of China, rainfall and drought affect the growth and photosynthetic activities of plants.Gross primary productivity(GPP) is one of the most important indices that measure the photosynthetic ability of plants.This paper focused on the GPP of two representative grassland species(Stipa krylovii Roshev.and Allium polyrhizum Turcz.ex Regel) to demonstrate the effect of a temporal rainfall on the two species.Our research was conducted in a temperate grassland in New Barag Right Banner, Hulun Buir City, Inner Mongolia Autonomous Region of China, in a dry year 2015.We measured net ecosystem productivity(NEP) and ecosystem respiration flux(ER) using a transparent chamber system and monitored the photosynthetically active radiation(PAR), air and soil temperature and humidity simultaneously.Based on the measured values of NEP and ER, we calculated the GPP of the two species before and after the rainfall.The saturated GPP per aboveground biomass(GPPAGB) of A.polyrhizum remarkably increased from 0.033(±0.018) to 0.185(±0.055) μmol CO2/(gdw·s) by 5.6-fold and that of S.krylovii decreased from 0.068(±0.021) to 0.034(±0.011) μmol CO2/(gdw·s) by 0.5-fold on the 1st and 2nd d after a 9.1 mm rainfall event compared to the values before the rainfall at low temperatures below 35℃.However, on the 1st and 2nd d after the rainfall, both of the saturated GPPAGB values of S.krylovii and A.polyrhizum were significantly lower at high temperatures above 35℃(0.018(±0.007) and 0.110(±0.061) μmol CO2/(gdw·s), respectively) than at low temperatures below 35℃(0.034(±0.011) and 0.185(±0.055) μmol CO2/(gdw·s), respectively).The results showed that the GPP responses to the temporal rainfall differed between S.krylovii and A.polyrhizum and strongly negative influenced by temperature.The temporal rainfall seems to be more effective on the GPP of A.polyrhizum than S.krylovii.These differences might be related to the different physiological and structural features, the coexistence of the species and their species-specific survival strategies.
基金supported by the National Natural Science Foundation of China (Grant No. 41302015)the National Basic Research Program of China (Grant No. 2015CB953803)
文摘Laoya Cave is a long-term occupation site of Late Paleolithic humans in the Yunnan-Guizhou Plateau, southwest China, where abundant lithic, bone materials were recovered. Dating by the AMS technique showed a significant depositional process during marine isotope stage(MIS) 3/2. In this study, the species spectrum was presented from the perspective of zooarchaeology and the mortality profile of large Cervidae was examined to help increase our understanding of the subsistence strategy of local people dealing with climate and environmental changes. The main part of the diet was focused on large Cervidae, and the dominance of Ungulates indicates effective management of the cave and local fauna. On the other hand, the mortality profiles of large Cervidae varied correspondingly with climate change. The evidence indicates a specialized hunting strategy that was also flexible, depending on the prevailing climate and environment.
基金This project was supported by the Natural Science Foundation of Hebei Province of China(No.C2021205006)the Science and Technology Project of the Hebei Education Department(No.ZD2021064).
文摘Ticks are external parasitic arthropods that can transmit a variety of pathogens by sucking blood.Low-temperature tolerance is essential for ticks to survive during the cold winter.Exploring the protein regulation mechanism of low-temperature tolerance of Haemaphysalis longicornis could help to explain how ticks survive in winter.In this study,the quantitative proteomics of several tissues of H.longicornis exposed to low temperature were studied by data independent acquisition technology.Totals of 3699,3422,and 1958 proteins were identified in the salivary gland,midgut,and ovary,respectively.The proteins involved in energy metabolism,cell signal transduction,protein synthesis and repair,and cytoskeleton synthesis changed under low-temperature stress.The comprehensive analysis of the protein regulation of multiple tissues of female ticks exposed to low temperature showed that maintaining cell homeostasis,maintaining cell viability,and enhancing cell tolerance were the most important means for ticks to maintain vital signs under low temperature.The expression of proteins involved in and regulating the above cell activities was the key to the survival of ticks under low temperatures.Through the analysis of a large amount of data,we found that the expression levels of arylamine N-acetyltransferase,inositol polyphosphate multikinase,and dual-specificity phosphatase were up-regulated under low temperature.We speculated that they might have important significance in low-temperature tolerance.Then,we performed RNA interference on the mRNA of these 3 proteins,and the results showed that the ability of female ticks to tolerate low temperatures decreased significantly.
文摘Deserts exhibit extreme climatic conditions.Small desert-dwelling vertebrates have physiological and behavioral adaptations to cope with these conditions,including the ability to seek shelter.We investigated the temperature(T)and relative humidity(RH)regulating properties of the soil cracks that characterize the extensive cracking-clay landscapes of arid Australia,and the extent of their use by 2 small marsupial species:fat-tailed and stripe-faced dunnarts(Sminthopsis crassicaudata and Sminthopsis macroura).We measured hourly(over 24-h periods)the T and RH of randomly-selected soil cracks compared to outside conditions,during 2 summers and 2 winters.We tracked 17 dunnarts(8 Sminthopsis crassicaudata and 9 Sminthopsis macroura)to quantify their use of cracks.Cracks consistently moderated microclimate,providing more stable conditions than available from non-crack points,which often displayed comparatively dramatic fluctuations in T and RH.Both dunnart species used crack shelters extensively.Cracks constitute important shelter for small animals during extreme conditions by providing a stable microclimate,which is typically cooler than outside conditions in summer and warmer in winter.Cracks likely play a fundamental sheltering role by sustaining the physiological needs of small mammal populations.Globally,cracking-clay areas are dominated by agricultural land uses,including livestock grazing.Management of these systems should focus not only on vegetation condition,but also on soil integrity,to maintain shelter resources for ground-dwelling fauna.
基金co-supported by the National Natural Science Foundation of China (No. 11672093)the Shanghai Aerospace Science and Technology Innovation Foundation (No. SAST2016039)
文摘This paper investigates a cooperative strategy for protecting an aerial target.The problem is solved as a game among four players(a target,two defenders,and a missile).In this scenario,the target launches two defenders(defender-1 and defender-2)simultaneously,to establish a oneway cooperation system(OCS)against an attacking missile.A new optimal evasion strategy for the target is also derived.During the engagement,the target takes into account the reaction of the attacking missile,and guides defender-1 to the interception point by receiving information from defender-1.Depending on the control effort of the target,defender-2 can choose appropriate launch conditions and use very limited maneuvering capability to intercept the missile.For adversaries with first-order dynamics,simulation results show that the OCS allows two defenders to intercept the missile.During the engagement,even if one defender or communication channel is broken,the OCS still allows an interception to be made,thus increasing the target’s survivability.