The frozen bodies of a young woolly mammoth(Mammuthus primigenius),a wild horse(Equus sp.)and a steppe bison(Bison priscus)were recently found in the northern Yakutia(northeastern Siberia).All specimens have preserved...The frozen bodies of a young woolly mammoth(Mammuthus primigenius),a wild horse(Equus sp.)and a steppe bison(Bison priscus)were recently found in the northern Yakutia(northeastern Siberia).All specimens have preserved bones,skin and soft tissues.Whereas the woolly mammoth and the Pleistocene horse were represented by partial frozen bodies,the steppe bison body was recovered in an absolutely complete state.All specimens were found frozen in the permafrost,with some of the tissues mummified.The wild horse and steppe bison are of Holocene age,and the mammoth is of Late Pleistocene age.展开更多
To analyze the causes affecting production situation of one pig farm in southwest region,group leader,assistant and related staffs in the pig farm were queried,mating and delivery situation of sow and dead-culling sit...To analyze the causes affecting production situation of one pig farm in southwest region,group leader,assistant and related staffs in the pig farm were queried,mating and delivery situation of sow and dead-culling situation ofpigletwere investigated.The results showed that(1) mating situation: mating 691 pigs,returning to love 42 pigs,abortion 4 pigs,mismatching rate was 7.59%.(2) Delivery situation: delivering 175 nests,total birth 2538,total piglet per fetus 14.5,average healthy piglet per fetus 10.12,invalid piglet rate was30.21%.Among them,mummy fetus,dead fetus,weak piglet and deformity accounted for 47.78%,35.64%,10.71% and 5.87% of invalid piglet.(3) Dead-culling situation: dead-culling rate in breeding process was 12.37%.Among them,diarrhea death wasthemain cause,accounting for 44.47%,followed by pressing,falling to the ground,disease,joint swelling,weakness and other causes,and they respectively accounted for 18.58%,13.36%,13.36%,8.56%,5.85% and 0.62%.展开更多
Diapause is an adaptation that insects have evolved to synchronize their life cycle with that of seasonal climatic changes and resources availability.However,cues for its induction are not always clear and,in some cas...Diapause is an adaptation that insects have evolved to synchronize their life cycle with that of seasonal climatic changes and resources availability.However,cues for its induction are not always clear and,in some cases,a maternal effect may be involved.At the population level,just a part of the individuals may exhibit diapause with important consequences in terms of winter survival.Moreover,clear indicators of diapause state are difficult to identify.Diapause induction was thus investigated in the aphid parasitoid species Aphidius ervi Haliday(Hymenoptera:Braconidae)developing in the aphid Sitobion avenae(Hemiptera:Aphididae)at four crossed photothermal regimes(16℃and 8℃,16:8 h L:D and 8:16 h L:D),and during 2 successive generations.We analyzed the reliability of changes in mummy color to assess for the diapausing state compared to dissections,and we measured parasitoid morphological and physiological traits.We observed that the proportion of dark brown mummies increased after one generation under low photothermal regime compared to other regimes.No diapause was recorded at 16℃,16:8 h L:D,while we observed 16.2%and 67.5%diapause incidence at 8℃,8:16 h L:D,at 1st and 2nd generation,respectively.Diapause induction is thus increased by short day-length conditions and low temperatures as well as by maternal effects.All parasitoid life-history traits(weight,size,fat content,water content,egg-load,and longevity)were affected by the photothermal regime and/or the generation.These results raise new questions on the environmental thresholds needed to induce diapause and on survival and adaptation potential of commercially available parasitoid strains in different environments.展开更多
China is always full of surprises.My foreign friends who come here discover things that shock and startle them,but they all agree that their wonder and respect for China never cease.
The ghosts of Columbus and his fellow European explorers can breathe a bit easier. They have long been accused of slaying New World natives not just with swords but also with germs. Supposedly, the sailors—and eventu...The ghosts of Columbus and his fellow European explorers can breathe a bit easier. They have long been accused of slaying New World natives not just with swords but also with germs. Supposedly, the sailors—and eventual settlers — brought with them the bugs for illnesses unknown in the Americas , including smallpox , measles , influenza , malaria and tuberculosis. Never having been exposed to these ailments,展开更多
Silkworm raising and silk reeling is a great contribution of ancient Chinese women to the world civilization and progress. When the Silk Road opened in the Hah Dynasty more than 2,000 years ago, westerners used to cal...Silkworm raising and silk reeling is a great contribution of ancient Chinese women to the world civilization and progress. When the Silk Road opened in the Hah Dynasty more than 2,000 years ago, westerners used to call China the Kingdom of Silk. The gauze dress unearthed from the Mawangdui No. 1 Tomb of the Han Dynasty in Hunan’s Changsha, is as thin as cicada’s wings and only weighs 49 grams. Made of high quality silk, this dress is as soft and light as the dress made of georgette, revealing the ancient Chinese weaving workers’ high skill and talent. It is a silk dress, the earliest and best preserved in the world currently. Also excavated from the same tomb is a mummified woman’s body. The woman was the wife of a prime minister of a展开更多
基金The authors are grateful to the late Vasiliy Gorokhov,the head of the tribal community‘Yukagir’(who passed away in Nov 2012),and to the Yukagir community for allowing us to borrow the specimens for this study in Yakutsk,Russia.The Scientific Research Institute of Applied Ecology of the North of Northeastern Federal University,Yakutsk and Bernard Buigues(Saint-Jean de Lus,France)helped with the logistics and provided funds for the specimens to be transported to Yakutsk in 2012.
文摘The frozen bodies of a young woolly mammoth(Mammuthus primigenius),a wild horse(Equus sp.)and a steppe bison(Bison priscus)were recently found in the northern Yakutia(northeastern Siberia).All specimens have preserved bones,skin and soft tissues.Whereas the woolly mammoth and the Pleistocene horse were represented by partial frozen bodies,the steppe bison body was recovered in an absolutely complete state.All specimens were found frozen in the permafrost,with some of the tissues mummified.The wild horse and steppe bison are of Holocene age,and the mammoth is of Late Pleistocene age.
基金Supported by the Fundamental Research Funds for the Central Universities:the Young Teachers Fund of Southwest Minzu University(2017NZYQN38)Innovative Scientific Research Project for Postgraduates of Southwest Minzu University(CX2018SZ43)
文摘To analyze the causes affecting production situation of one pig farm in southwest region,group leader,assistant and related staffs in the pig farm were queried,mating and delivery situation of sow and dead-culling situation ofpigletwere investigated.The results showed that(1) mating situation: mating 691 pigs,returning to love 42 pigs,abortion 4 pigs,mismatching rate was 7.59%.(2) Delivery situation: delivering 175 nests,total birth 2538,total piglet per fetus 14.5,average healthy piglet per fetus 10.12,invalid piglet rate was30.21%.Among them,mummy fetus,dead fetus,weak piglet and deformity accounted for 47.78%,35.64%,10.71% and 5.87% of invalid piglet.(3) Dead-culling situation: dead-culling rate in breeding process was 12.37%.Among them,diarrhea death wasthemain cause,accounting for 44.47%,followed by pressing,falling to the ground,disease,joint swelling,weakness and other causes,and they respectively accounted for 18.58%,13.36%,13.36%,8.56%,5.85% and 0.62%.
文摘Diapause is an adaptation that insects have evolved to synchronize their life cycle with that of seasonal climatic changes and resources availability.However,cues for its induction are not always clear and,in some cases,a maternal effect may be involved.At the population level,just a part of the individuals may exhibit diapause with important consequences in terms of winter survival.Moreover,clear indicators of diapause state are difficult to identify.Diapause induction was thus investigated in the aphid parasitoid species Aphidius ervi Haliday(Hymenoptera:Braconidae)developing in the aphid Sitobion avenae(Hemiptera:Aphididae)at four crossed photothermal regimes(16℃and 8℃,16:8 h L:D and 8:16 h L:D),and during 2 successive generations.We analyzed the reliability of changes in mummy color to assess for the diapausing state compared to dissections,and we measured parasitoid morphological and physiological traits.We observed that the proportion of dark brown mummies increased after one generation under low photothermal regime compared to other regimes.No diapause was recorded at 16℃,16:8 h L:D,while we observed 16.2%and 67.5%diapause incidence at 8℃,8:16 h L:D,at 1st and 2nd generation,respectively.Diapause induction is thus increased by short day-length conditions and low temperatures as well as by maternal effects.All parasitoid life-history traits(weight,size,fat content,water content,egg-load,and longevity)were affected by the photothermal regime and/or the generation.These results raise new questions on the environmental thresholds needed to induce diapause and on survival and adaptation potential of commercially available parasitoid strains in different environments.
文摘China is always full of surprises.My foreign friends who come here discover things that shock and startle them,but they all agree that their wonder and respect for China never cease.
文摘The ghosts of Columbus and his fellow European explorers can breathe a bit easier. They have long been accused of slaying New World natives not just with swords but also with germs. Supposedly, the sailors—and eventual settlers — brought with them the bugs for illnesses unknown in the Americas , including smallpox , measles , influenza , malaria and tuberculosis. Never having been exposed to these ailments,
文摘Silkworm raising and silk reeling is a great contribution of ancient Chinese women to the world civilization and progress. When the Silk Road opened in the Hah Dynasty more than 2,000 years ago, westerners used to call China the Kingdom of Silk. The gauze dress unearthed from the Mawangdui No. 1 Tomb of the Han Dynasty in Hunan’s Changsha, is as thin as cicada’s wings and only weighs 49 grams. Made of high quality silk, this dress is as soft and light as the dress made of georgette, revealing the ancient Chinese weaving workers’ high skill and talent. It is a silk dress, the earliest and best preserved in the world currently. Also excavated from the same tomb is a mummified woman’s body. The woman was the wife of a prime minister of a
