随着无线电技术在水上搜救上的应用,多种人员落水(Man Over Board,简称MOB)定位搜救终端产品上市销售。本文通过将各类水上搜救通信方式集成融合,设计开发一款多通道无线电人员落水定位搜救终端,在海上作业人员意外落水后,能及时给卫星...随着无线电技术在水上搜救上的应用,多种人员落水(Man Over Board,简称MOB)定位搜救终端产品上市销售。本文通过将各类水上搜救通信方式集成融合,设计开发一款多通道无线电人员落水定位搜救终端,在海上作业人员意外落水后,能及时给卫星、船舶、飞机等多种救援方式提供遇险位置信息,从而提高搜救效率,保障海上人员生命安全。展开更多
Predation is an important source of natural selection on prey species and has resulted in adaptations such as antipredator vocal signals,which can alert others to the presence of predators and solicit cooperative atta...Predation is an important source of natural selection on prey species and has resulted in adaptations such as antipredator vocal signals,which can alert others to the presence of predators and solicit cooperative attack.Although vocal alarm signals of birds have been well studied,they are poorly known in tropical African species.To address this lack of information,the antipredatory signals and responses of two lapwings(Wattled Lapwing Vanellus senegallus and Spur-winged Lapwing Vanellus spinosus)to potential predators were investigated using data collected from focal observation,distance measurements,focal recordings,and playback experiment.The lapwing calls elicited to predators were classified as alarm or mobbing calls based on whether the calls elicited alert behavior or attack from other lapwings.Discriminant linear analysis(DLA)was used to compare the time and frequency parameters of the call types measured in Raven PRO.Also,lapwings’responses to intruders,alert and start distance,time of day,and latency,as well as the effects of flock size and distance to cover were examined.About 48%of all calls was correctly classified by DLA.The best predictors of call type for the lapwings were maximum frequency and high frequency.Both alarm and mobbing calls were elicited by African Wattled Lapwings to dogs and humans.Mobbing calls were elicited to intruders by the Spur-winged Lapwings.Alert distance was positively associated with start distance,and differed between morning and evening in both lapwings.With scarce information from tropical Africa,this study put in perspective vocal and antipredator behavior of lapwing species in Africa.展开更多
The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be...The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be less useful for industrial purposes.It can,however,serve as a hub for ongoing research on coal-based derivative products.The aim of this research work is to investigate the mineralogical and geochemical compositions of the coal,mine overburden(MOB)and shale samples taken from the Makum coal field and also on establishing a mutual relationship between them.To characterize the geochemical controlling factors of the Makum coal field,the study employs coal petrography,FTIR,mineralogical,and geochemical analysis.According to X-ray diffraction analysis,the major minerals like quartz,kaolinite,haematite,illite,pyrite,and calcite are present in coal and MOB.Pyrite is observed by SEM-EDS analysis as cubic-shaped particles that are smaller than a fewμm in size.The presence of sulfide minerals represents a phase of pyrite mineralization.The petrography study was used to better understand the environment that existed during the formation of the plant material,which aids us in determining the quantity of detrital mineral sediment contained in the coal.According to the ICP-MS analysis,the samples indicate significant levels of rare earth elements including yttrium.The present study reveals higher concentrations of poten-tial hazardous elements in the coal samples,with V,Cr,Ni,Cu,and Zn content in coal being considerably enriched compared to world-average concentrations.The correlation analysis reveals that the potential hazardous elements like Co,Ni,As,and Cu are associated with pyrite as they have strong affinity towards pyrite.Thus,numerous minerals and rare earth elements(REEs)exist,opening up a fresh avenue for more research in the area.This study also assists researchers in understanding the significance of Makum coal and provides numerous ideas for coal characterization.展开更多
Background: Resemblance to raptors such as hawks(Accipiter spp.) is considered to be an adaptive strategy of cuckoos(Cuculus spp.), which has evolved to protect cuckoos against host attacks. However, the effectiveness...Background: Resemblance to raptors such as hawks(Accipiter spp.) is considered to be an adaptive strategy of cuckoos(Cuculus spp.), which has evolved to protect cuckoos against host attacks. However, the effectiveness of the mimicry remains controversial, and is not yet fully studied for highly aggressive hosts.Methods: We evaluated the effectiveness of sparrowhawk(Accipiter nisus) mimicry by common cuckoos(Cuculus canorus) in oriental reed warblers(Acrocephaus orientalis), which are highly aggressive hosts. Using a both the single and the paired dummy experiment, defense behaviors and attack intensities of oriental reed warblers against common cuckoos, sparrowhawks and oriental turtle doves(Streptopelia orientalis) were assessed.Results: Oriental reed warblers exhibit strong nest defense behaviors, and such behaviors do not change with breeding stage(i.e., egg stage and nestling stage). Furthermore, assistance from conspecific helpers may increase attack intensities. However, they were deterred from mobbing overall by the presence of the hawk.Conclusions: Oriental reed warblers are able to distinguish cuckoos from harmless doves. However, they may be deterred from mobbing by the presence of the predatory hawk, suggesting hawk mimicry may be ineffective and does not reduce attacks of cuckoos by highly aggressive hosts.展开更多
文摘随着无线电技术在水上搜救上的应用,多种人员落水(Man Over Board,简称MOB)定位搜救终端产品上市销售。本文通过将各类水上搜救通信方式集成融合,设计开发一款多通道无线电人员落水定位搜救终端,在海上作业人员意外落水后,能及时给卫星、船舶、飞机等多种救援方式提供遇险位置信息,从而提高搜救效率,保障海上人员生命安全。
基金funding(No.217)from the A.P.Leventis Foundation Scholarship(to F.R.J).
文摘Predation is an important source of natural selection on prey species and has resulted in adaptations such as antipredator vocal signals,which can alert others to the presence of predators and solicit cooperative attack.Although vocal alarm signals of birds have been well studied,they are poorly known in tropical African species.To address this lack of information,the antipredatory signals and responses of two lapwings(Wattled Lapwing Vanellus senegallus and Spur-winged Lapwing Vanellus spinosus)to potential predators were investigated using data collected from focal observation,distance measurements,focal recordings,and playback experiment.The lapwing calls elicited to predators were classified as alarm or mobbing calls based on whether the calls elicited alert behavior or attack from other lapwings.Discriminant linear analysis(DLA)was used to compare the time and frequency parameters of the call types measured in Raven PRO.Also,lapwings’responses to intruders,alert and start distance,time of day,and latency,as well as the effects of flock size and distance to cover were examined.About 48%of all calls was correctly classified by DLA.The best predictors of call type for the lapwings were maximum frequency and high frequency.Both alarm and mobbing calls were elicited by African Wattled Lapwings to dogs and humans.Mobbing calls were elicited to intruders by the Spur-winged Lapwings.Alert distance was positively associated with start distance,and differed between morning and evening in both lapwings.With scarce information from tropical Africa,this study put in perspective vocal and antipredator behavior of lapwing species in Africa.
基金MoES (Govt of India)for his financial assistance to our project (GPP364).
文摘The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be less useful for industrial purposes.It can,however,serve as a hub for ongoing research on coal-based derivative products.The aim of this research work is to investigate the mineralogical and geochemical compositions of the coal,mine overburden(MOB)and shale samples taken from the Makum coal field and also on establishing a mutual relationship between them.To characterize the geochemical controlling factors of the Makum coal field,the study employs coal petrography,FTIR,mineralogical,and geochemical analysis.According to X-ray diffraction analysis,the major minerals like quartz,kaolinite,haematite,illite,pyrite,and calcite are present in coal and MOB.Pyrite is observed by SEM-EDS analysis as cubic-shaped particles that are smaller than a fewμm in size.The presence of sulfide minerals represents a phase of pyrite mineralization.The petrography study was used to better understand the environment that existed during the formation of the plant material,which aids us in determining the quantity of detrital mineral sediment contained in the coal.According to the ICP-MS analysis,the samples indicate significant levels of rare earth elements including yttrium.The present study reveals higher concentrations of poten-tial hazardous elements in the coal samples,with V,Cr,Ni,Cu,and Zn content in coal being considerably enriched compared to world-average concentrations.The correlation analysis reveals that the potential hazardous elements like Co,Ni,As,and Cu are associated with pyrite as they have strong affinity towards pyrite.Thus,numerous minerals and rare earth elements(REEs)exist,opening up a fresh avenue for more research in the area.This study also assists researchers in understanding the significance of Makum coal and provides numerous ideas for coal characterization.
基金supported by the National Natural Science Foundation of China(Nos.31672303 to CY,31472013 and 31772453 to WL)
文摘Background: Resemblance to raptors such as hawks(Accipiter spp.) is considered to be an adaptive strategy of cuckoos(Cuculus spp.), which has evolved to protect cuckoos against host attacks. However, the effectiveness of the mimicry remains controversial, and is not yet fully studied for highly aggressive hosts.Methods: We evaluated the effectiveness of sparrowhawk(Accipiter nisus) mimicry by common cuckoos(Cuculus canorus) in oriental reed warblers(Acrocephaus orientalis), which are highly aggressive hosts. Using a both the single and the paired dummy experiment, defense behaviors and attack intensities of oriental reed warblers against common cuckoos, sparrowhawks and oriental turtle doves(Streptopelia orientalis) were assessed.Results: Oriental reed warblers exhibit strong nest defense behaviors, and such behaviors do not change with breeding stage(i.e., egg stage and nestling stage). Furthermore, assistance from conspecific helpers may increase attack intensities. However, they were deterred from mobbing overall by the presence of the hawk.Conclusions: Oriental reed warblers are able to distinguish cuckoos from harmless doves. However, they may be deterred from mobbing by the presence of the predatory hawk, suggesting hawk mimicry may be ineffective and does not reduce attacks of cuckoos by highly aggressive hosts.
