During July to November of 2008, the artisanal fisheries captured juvenile sharks belonging to the Carcharhinus and Sphyrnidae family in the Veracruz Reef System (south western Gulf of Mexico). The three most abundant...During July to November of 2008, the artisanal fisheries captured juvenile sharks belonging to the Carcharhinus and Sphyrnidae family in the Veracruz Reef System (south western Gulf of Mexico). The three most abundant organisms were of the species Sphyrna lewini, Carcharhinus brevipinna and Rhizoprionodon terraenovae. Local fisherman recognized five captured areas of sharks as a direct way or bycatch. Some of these areas are located near to eddies formations and river discharges (high productivity areas). These top predators fed on benthic and demersal prey of coastal and reef habits had been the Teleost group the most important item in its diet. However it is possible to observe differences in its feeding tendency.展开更多
As apex predators, sharks are of ecological and conservation importance in marine ecosystems. In this study, trophic positions of sharks were estimated using stable isotope ratios of carbon and nitrogen for five repre...As apex predators, sharks are of ecological and conservation importance in marine ecosystems. In this study, trophic positions of sharks were estimated using stable isotope ratios of carbon and nitrogen for five representative species caught by the Chinese longline fleet in the mid-east Pacific, i.e., the blue shark （Prionace glauca）, the bigeye thresher shark （Alopias superciliosus）, the silky shark （Carcharhinus falciformis）, the scalloped hammerhead （Sphyrna lewini）, and the oceanic whitetip shark （Car-charhinus longimanus）. Of these species, oceanic whitetip shark has the lowest trophic level and mean 815N value （3.9 and 14.93%o± 0.84%o）, whereas bigeye thresher shark has the highest level/values （4.5 and 17.02%o±1.21%o, respectively）. The bigeye thresher shark has significantly higher 515N value than other shark species, indicating its higher trophic position. The blue shark and oceanic whitetip shark has significantly higher 813C values than bigeye thresher shark, silky shark and scalloped hammerhead, possibly due to different diets and/or living habitats. The stable isotope data and stomach content data are highly consistent, suggesting that sta-ble isotope analysis supplements traditional feeding ecology study of sharks, and thus contributes to understanding their trophic linkage.展开更多
Sorting objects and events into categories and concepts is an important cognitive prerequisite that spares an individual the learning of every object or situation encountered in its daily life.Accordingly,specific ite...Sorting objects and events into categories and concepts is an important cognitive prerequisite that spares an individual the learning of every object or situation encountered in its daily life.Accordingly,specific items are classified in general groups that allow fast responses to novel situations.The present study assessed whether bamboo sharks Chiloscyllium griseum and Malawi cichlids Pseudotropheus zebra can distinguish sets of stimuli(each stimulus consisting of two abstract,geometric objects)that meet two conceptual preconditions,i.e.,(1)"sameness"versus"difference"and(2)a certain spatial arrangement of both objects.In two alternative forced choice experiments,individuals were first trained to choose two different,vertically arranged objects from two different but horizontally arranged ones.Pair discriminations were followed by extensive transfer test experiments.Transfer tests using stimuli consisting of(a)black and gray circles and(b)squares with novel geometric patterns provided conflicting information with respect to the learnt rule"choose two different,vertically arranged objects",thereby investigating(1)the individuals'ability to transfer previously gained knowledge to novel stimuli and(2)the abstract relational concept(s)or rule(s)applied to categorize these novel objects.Present results suggest that the level of processing and usage of both abstract concepts differed considerably between bamboo sharks and Malawi cichlids.Bamboo sharks seemed to combine both concepts-although not with equal but hierarchical prominence-pointing to advanced cognitive capabilities.Conversely,Malawi cichlids had difficulties in discriminating between symbols and failed to apply the acquired training knowledge on new sets of geometric and,in particular,gray-level transfer stimuli.展开更多
The early white shark Carcharodon Smith, 1838 with the fossil Carcharodon auriculatus (Blainville, 1818) and the extinct megatooth shark Otodus Agassiz, 1843 with species Otodus sokolovi (Jaeckel, 1895) were both pres...The early white shark Carcharodon Smith, 1838 with the fossil Carcharodon auriculatus (Blainville, 1818) and the extinct megatooth shark Otodus Agassiz, 1843 with species Otodus sokolovi (Jaeckel, 1895) were both present in the European proto North Sea Basin about 47.8 - 41.3 m.y. ago (Lutetian, early Middle Eocene), as well as in the Tethys realm around the Afican-Eurasian shallow marine habitats. Both top predators developed to be polyphyletic, with possible two different lamnid shark ancestors within the Early Paleocene to Early Eocene timespan with Carcharodon (white shark line-age) and Otodus (megatooth shark lineage). Their sawblade teeth developed during the early Paleogene as the result of adaptation to feeding on various marine new rising mammals, coinciding with three main waves of evolutionary emergence of seals, sirenians, and whales in parallel with the evolution of these large predatory sharks. Megatooth sharks specialized in hunting whales and sirenians only on the coastal shelves of warm oceans and disappeared globally in the Pleistocene due to climate change and ocean cooling. The cold-water adapted early white sharks have survived until the present day with body temperate change adaptation in warm to temperate oceans and are proposed to have specialized on coastal seal hunting already50 m.y. ago.展开更多
INTRODUCTION.Chondrichthyans(sharks,rays,and chimaeras)constitute one of the most threatened groups of marine animals,with more than one-third of the species estimated to be threatened,primarily as a consequence of fi...INTRODUCTION.Chondrichthyans(sharks,rays,and chimaeras)constitute one of the most threatened groups of marine animals,with more than one-third of the species estimated to be threatened,primarily as a consequence of fisheries activities(McClenachan et al.2012;Dulvy et al.2014,2021).展开更多
Using clever tactics and the allure of rare finds,the thrill of livestreamed collectable card sales is pulling in bigger crowds,especially minors.However,experts warn that these sales mimic gambling,yet operate with l...Using clever tactics and the allure of rare finds,the thrill of livestreamed collectable card sales is pulling in bigger crowds,especially minors.However,experts warn that these sales mimic gambling,yet operate with little oversight to protect young buyers.It was 3 am,but Wang Ke still had over 1,000 viewers.She is known for her unboxing livestreams of collectible cards.This session,the cards were My Little Pony,a 40-year-old US animation franchise popular in China since the early 2010s.展开更多
Despite over 70 years of research on shark repellents,few practical and reliable solutions to prevent shark attacks on humans or reduce shark bycatch and depredation in commercial fisheries have been developed.In larg...Despite over 70 years of research on shark repellents,few practical and reliable solutions to prevent shark attacks on humans or reduce shark bycatch and depredation in commercial fisheries have been developed.In large part,this deficiency stems from a lack of fundamental knowledge of the sensory cues that drive predatory behavior in sharks.However,the widespread use of shark repellents is also hampered by the physical constraints and technical or logistical difficulties of deploying substances or devices in an open-water marine environment to prevent an unpredictable interaction with a complex animal.Here,we summarize the key attributes of the various sensory systems of sharks and highlight residual knowledge gaps that are relevant to the development of effective shark repellents.We also review the most recent advances in shark repellent technology within the broader historical context of research on shark repellents and shark sensory systems.We conclude with suggestions for future research that may enhance the efficacy of shark repellent devices,in particular,the continued need for basic research on shark sensory biology and the use of a multi-sensory approach when developing or deploying shark repellent technology.展开更多
Scientists have suspected for a while that Greenland sharks live extremely long lives,but they didnt have a way to determine how long.The age of other shark species can be estimated by counting growth bands on fin spi...Scientists have suspected for a while that Greenland sharks live extremely long lives,but they didnt have a way to determine how long.The age of other shark species can be estimated by counting growth bands on fin spines(鳍脊)or on the sharksvertebrae(脊椎),much like rings of a tree.Greenland sharks,however,have no fin spines and no hard tissues in their bodies.Their vertebrae are too soft to form the growth bands seen in other sharks.Scientists could only guess that the sharks lived a long time based on what they knew—the sharks grow at a very slow rate and they can reach 6 meters in size.展开更多
In the workshop of Guangshan White Shark Card Clothing Co.,Ltd.,precision machines are meticulously crafting the tips of card clothing with millimeter-level accuracy.These seemingly tiny textile accessories play a cru...In the workshop of Guangshan White Shark Card Clothing Co.,Ltd.,precision machines are meticulously crafting the tips of card clothing with millimeter-level accuracy.These seemingly tiny textile accessories play a crucial role in the global cotton and chemical fiber industry chains.As China's textile industry encounters trade barriers in the process of globalization,this company specializing in card clothing manufacturing is striving to explore a differentiated path in overseas markets.展开更多
Surgical electrodes are frequently associated with disadvantages such as high surface adhesion and severe thermal damage to adjacent normal tissues,which threaten operation quality and patient safety.In this study,by ...Surgical electrodes are frequently associated with disadvantages such as high surface adhesion and severe thermal damage to adjacent normal tissues,which threaten operation quality and patient safety.In this study,by mimicking the micromorphology and bio-anti-adhesion of shark skin,we proposed a strategy that utilized nanoscale aluminium oxide(Al_(2)O_(3))films deposited on bioinspired shark skin(BSS)microstructures to design a composite surface(Al_(2)O_(3)@BSS)and integrated it into both flat sides of the surgical electrodes.Micro/nano-manufacturing of the Al_(2)O_(3)@BSS surface was sequentially accomplished using nanosecond laser texturing,atomic layer deposition,and low-temperature annealing,endowing it with excellent blood-repellent properties.Visualisation experiments revealed that the tensile stress gradient of the blood coagulum with increasing thickness under a thermal field prompted it to separate from the Al_(2)O_(3)@BSS surface,resulting in anti-adhesion.Furthermore,it was observed for the first time that Al_(2)O_(3) films could transiently excite discharge along a dielectric surface(DADS)to ablate tissues while suppressing Joule heat,thereby minimising thermal damage.A combination of ex vivo tissue and living mouse experiments demonstrated that the Al_(2)O_(3)@BSS electrodes exhibited optimal comprehensive performance in terms of anti-adhesion,damage minimisation,and drag reduction.In addition,the Al_(2)O_(3)@BSS electrodes possessed remarkable antibacterial efficacy against E.coli and S.aureus.The proposed strategy can meet the extreme application requirements of surgical electrodes to improve operation quality and offer valuable insights for future studies.展开更多
随着空间数据的与日俱增,传统依托于单节点的空间数据管理方法,已难以满足海量数据高并发的需求。云计算的兴起带来机遇与挑战,分布式技术与数据库技术的优势互补,为云计算下高效的数据管理提供了可能。本文提出一种在分布式计算引擎(Sh...随着空间数据的与日俱增,传统依托于单节点的空间数据管理方法,已难以满足海量数据高并发的需求。云计算的兴起带来机遇与挑战,分布式技术与数据库技术的优势互补,为云计算下高效的数据管理提供了可能。本文提出一种在分布式计算引擎(Shark/Spark)中集合之关键技术(包括空间数据映射、空间数据加载、数据备份及空间查询等),将空间数据库对空间数据的高效存储、索引及查询优势与分布式计算引擎对复杂计算的优势相结合,实现一种基于Shark/Spark的分布式空间数据分析框架。在具体实现中,通过空间自定义函数和空间函数下推2种方式实现空间查询,结果表明,影响返回结果数据量的空间查询更适合下推给空间数据库完成,而不影响返回结果数据量的空间查询,利用分布式计算引擎直接运算更有优势。同时,通过与现有的一种分布式GIS方案(Arc GIS on Hadoop)对比发现,空间数据库的空间索引可有效提高查询效率,空间数据管理也更加独立。展开更多
Aim To purify hepatocyte regeneration stimulatory factor from shark liver and research its molecular feature and activity. Methods and Results Hepatocyte regeneration stimulatory factor (sHRSF) was isolated from hea...Aim To purify hepatocyte regeneration stimulatory factor from shark liver and research its molecular feature and activity. Methods and Results Hepatocyte regeneration stimulatory factor (sHRSF) was isolated from healthy shark livers and separated by homogenization, freezing melting, heat treating, centrifugation, and ultrafiltration. HRSF activity was found mainly in the subfraction of molecular weight less than 30 000 daltons. This crude ultrafiltrate was further purified successively by DEAE Sepharose fast flow chromatography, FPLC Resource 30Q, Resource Q and Mono Q chromatography. A single band was displayed on sodium dodecyl sulfate polyacrylamide gel electrophoresis, which corresponds to molecular weight of 14 600 daltons. The characteristic absorption was obtained at the wavelength 276 nm. The isoelectric point was about 5 1. It contained 18 amino acids and the 15 N terminal amino acid residues were LVGPIGAVGPAGKDG. It had a significant activity in stimulating liver to regenerate. Conclusion We obtained an unknown new active protein, that is hepatocyte regeneration stimulatory factor from shark liver (sHRSF).展开更多
文摘During July to November of 2008, the artisanal fisheries captured juvenile sharks belonging to the Carcharhinus and Sphyrnidae family in the Veracruz Reef System (south western Gulf of Mexico). The three most abundant organisms were of the species Sphyrna lewini, Carcharhinus brevipinna and Rhizoprionodon terraenovae. Local fisherman recognized five captured areas of sharks as a direct way or bycatch. Some of these areas are located near to eddies formations and river discharges (high productivity areas). These top predators fed on benthic and demersal prey of coastal and reef habits had been the Teleost group the most important item in its diet. However it is possible to observe differences in its feeding tendency.
基金Li Yunkai was supported by the National Natural Science Foundation of China (No.41206124)Ph.D.Programs Foundation of Ministry of Education of China (No.201 23104120001)+3 种基金the ‘Chen Guang’ Project of Shanghai Municipal Education Commission (No.D8004-10-0206)the Shanghai Education Development Foundation (No.B-8102-10-0084)Zhu Jiangfeng and Dai Xiaojie were supported by the National Natural Science Foundation of China (No.41106118)the Scientific Observing and Experimental Station of Oceanic Fishery Resources, Ministry of Agriculture, China
文摘As apex predators, sharks are of ecological and conservation importance in marine ecosystems. In this study, trophic positions of sharks were estimated using stable isotope ratios of carbon and nitrogen for five representative species caught by the Chinese longline fleet in the mid-east Pacific, i.e., the blue shark （Prionace glauca）, the bigeye thresher shark （Alopias superciliosus）, the silky shark （Carcharhinus falciformis）, the scalloped hammerhead （Sphyrna lewini）, and the oceanic whitetip shark （Car-charhinus longimanus）. Of these species, oceanic whitetip shark has the lowest trophic level and mean 815N value （3.9 and 14.93%o± 0.84%o）, whereas bigeye thresher shark has the highest level/values （4.5 and 17.02%o±1.21%o, respectively）. The bigeye thresher shark has significantly higher 515N value than other shark species, indicating its higher trophic position. The blue shark and oceanic whitetip shark has significantly higher 813C values than bigeye thresher shark, silky shark and scalloped hammerhead, possibly due to different diets and/or living habitats. The stable isotope data and stomach content data are highly consistent, suggesting that sta-ble isotope analysis supplements traditional feeding ecology study of sharks, and thus contributes to understanding their trophic linkage.
基金This study was funded by a DFG Grant(SCHL,1919/4-1)to V.S.
文摘Sorting objects and events into categories and concepts is an important cognitive prerequisite that spares an individual the learning of every object or situation encountered in its daily life.Accordingly,specific items are classified in general groups that allow fast responses to novel situations.The present study assessed whether bamboo sharks Chiloscyllium griseum and Malawi cichlids Pseudotropheus zebra can distinguish sets of stimuli(each stimulus consisting of two abstract,geometric objects)that meet two conceptual preconditions,i.e.,(1)"sameness"versus"difference"and(2)a certain spatial arrangement of both objects.In two alternative forced choice experiments,individuals were first trained to choose two different,vertically arranged objects from two different but horizontally arranged ones.Pair discriminations were followed by extensive transfer test experiments.Transfer tests using stimuli consisting of(a)black and gray circles and(b)squares with novel geometric patterns provided conflicting information with respect to the learnt rule"choose two different,vertically arranged objects",thereby investigating(1)the individuals'ability to transfer previously gained knowledge to novel stimuli and(2)the abstract relational concept(s)or rule(s)applied to categorize these novel objects.Present results suggest that the level of processing and usage of both abstract concepts differed considerably between bamboo sharks and Malawi cichlids.Bamboo sharks seemed to combine both concepts-although not with equal but hierarchical prominence-pointing to advanced cognitive capabilities.Conversely,Malawi cichlids had difficulties in discriminating between symbols and failed to apply the acquired training knowledge on new sets of geometric and,in particular,gray-level transfer stimuli.
文摘The early white shark Carcharodon Smith, 1838 with the fossil Carcharodon auriculatus (Blainville, 1818) and the extinct megatooth shark Otodus Agassiz, 1843 with species Otodus sokolovi (Jaeckel, 1895) were both present in the European proto North Sea Basin about 47.8 - 41.3 m.y. ago (Lutetian, early Middle Eocene), as well as in the Tethys realm around the Afican-Eurasian shallow marine habitats. Both top predators developed to be polyphyletic, with possible two different lamnid shark ancestors within the Early Paleocene to Early Eocene timespan with Carcharodon (white shark line-age) and Otodus (megatooth shark lineage). Their sawblade teeth developed during the early Paleogene as the result of adaptation to feeding on various marine new rising mammals, coinciding with three main waves of evolutionary emergence of seals, sirenians, and whales in parallel with the evolution of these large predatory sharks. Megatooth sharks specialized in hunting whales and sirenians only on the coastal shelves of warm oceans and disappeared globally in the Pleistocene due to climate change and ocean cooling. The cold-water adapted early white sharks have survived until the present day with body temperate change adaptation in warm to temperate oceans and are proposed to have specialized on coastal seal hunting already50 m.y. ago.
文摘INTRODUCTION.Chondrichthyans(sharks,rays,and chimaeras)constitute one of the most threatened groups of marine animals,with more than one-third of the species estimated to be threatened,primarily as a consequence of fisheries activities(McClenachan et al.2012;Dulvy et al.2014,2021).
文摘Using clever tactics and the allure of rare finds,the thrill of livestreamed collectable card sales is pulling in bigger crowds,especially minors.However,experts warn that these sales mimic gambling,yet operate with little oversight to protect young buyers.It was 3 am,but Wang Ke still had over 1,000 viewers.She is known for her unboxing livestreams of collectible cards.This session,the cards were My Little Pony,a 40-year-old US animation franchise popular in China since the early 2010s.
基金NSH and SPC are supported by The University of Western Australia,The Western Australian State Government,The Sea World Research and Rescue Foundation,and the Australian Research Council.
文摘Despite over 70 years of research on shark repellents,few practical and reliable solutions to prevent shark attacks on humans or reduce shark bycatch and depredation in commercial fisheries have been developed.In large part,this deficiency stems from a lack of fundamental knowledge of the sensory cues that drive predatory behavior in sharks.However,the widespread use of shark repellents is also hampered by the physical constraints and technical or logistical difficulties of deploying substances or devices in an open-water marine environment to prevent an unpredictable interaction with a complex animal.Here,we summarize the key attributes of the various sensory systems of sharks and highlight residual knowledge gaps that are relevant to the development of effective shark repellents.We also review the most recent advances in shark repellent technology within the broader historical context of research on shark repellents and shark sensory systems.We conclude with suggestions for future research that may enhance the efficacy of shark repellent devices,in particular,the continued need for basic research on shark sensory biology and the use of a multi-sensory approach when developing or deploying shark repellent technology.
文摘Scientists have suspected for a while that Greenland sharks live extremely long lives,but they didnt have a way to determine how long.The age of other shark species can be estimated by counting growth bands on fin spines(鳍脊)or on the sharksvertebrae(脊椎),much like rings of a tree.Greenland sharks,however,have no fin spines and no hard tissues in their bodies.Their vertebrae are too soft to form the growth bands seen in other sharks.Scientists could only guess that the sharks lived a long time based on what they knew—the sharks grow at a very slow rate and they can reach 6 meters in size.
文摘In the workshop of Guangshan White Shark Card Clothing Co.,Ltd.,precision machines are meticulously crafting the tips of card clothing with millimeter-level accuracy.These seemingly tiny textile accessories play a crucial role in the global cotton and chemical fiber industry chains.As China's textile industry encounters trade barriers in the process of globalization,this company specializing in card clothing manufacturing is striving to explore a differentiated path in overseas markets.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52275425,52405473,and 52405472)the Natural Science Foundation of Guangdong Province(Grant No.2024A1515010993)。
文摘Surgical electrodes are frequently associated with disadvantages such as high surface adhesion and severe thermal damage to adjacent normal tissues,which threaten operation quality and patient safety.In this study,by mimicking the micromorphology and bio-anti-adhesion of shark skin,we proposed a strategy that utilized nanoscale aluminium oxide(Al_(2)O_(3))films deposited on bioinspired shark skin(BSS)microstructures to design a composite surface(Al_(2)O_(3)@BSS)and integrated it into both flat sides of the surgical electrodes.Micro/nano-manufacturing of the Al_(2)O_(3)@BSS surface was sequentially accomplished using nanosecond laser texturing,atomic layer deposition,and low-temperature annealing,endowing it with excellent blood-repellent properties.Visualisation experiments revealed that the tensile stress gradient of the blood coagulum with increasing thickness under a thermal field prompted it to separate from the Al_(2)O_(3)@BSS surface,resulting in anti-adhesion.Furthermore,it was observed for the first time that Al_(2)O_(3) films could transiently excite discharge along a dielectric surface(DADS)to ablate tissues while suppressing Joule heat,thereby minimising thermal damage.A combination of ex vivo tissue and living mouse experiments demonstrated that the Al_(2)O_(3)@BSS electrodes exhibited optimal comprehensive performance in terms of anti-adhesion,damage minimisation,and drag reduction.In addition,the Al_(2)O_(3)@BSS electrodes possessed remarkable antibacterial efficacy against E.coli and S.aureus.The proposed strategy can meet the extreme application requirements of surgical electrodes to improve operation quality and offer valuable insights for future studies.
文摘随着空间数据的与日俱增,传统依托于单节点的空间数据管理方法,已难以满足海量数据高并发的需求。云计算的兴起带来机遇与挑战,分布式技术与数据库技术的优势互补,为云计算下高效的数据管理提供了可能。本文提出一种在分布式计算引擎(Shark/Spark)中集合之关键技术(包括空间数据映射、空间数据加载、数据备份及空间查询等),将空间数据库对空间数据的高效存储、索引及查询优势与分布式计算引擎对复杂计算的优势相结合,实现一种基于Shark/Spark的分布式空间数据分析框架。在具体实现中,通过空间自定义函数和空间函数下推2种方式实现空间查询,结果表明,影响返回结果数据量的空间查询更适合下推给空间数据库完成,而不影响返回结果数据量的空间查询,利用分布式计算引擎直接运算更有优势。同时,通过与现有的一种分布式GIS方案(Arc GIS on Hadoop)对比发现,空间数据库的空间索引可有效提高查询效率,空间数据管理也更加独立。
基金NationalMarine863Project (No .2 0 0 1AA62 40 90),NationalNaturalScienceFoundationofChina (No .3 0 17110 3 )
文摘Aim To purify hepatocyte regeneration stimulatory factor from shark liver and research its molecular feature and activity. Methods and Results Hepatocyte regeneration stimulatory factor (sHRSF) was isolated from healthy shark livers and separated by homogenization, freezing melting, heat treating, centrifugation, and ultrafiltration. HRSF activity was found mainly in the subfraction of molecular weight less than 30 000 daltons. This crude ultrafiltrate was further purified successively by DEAE Sepharose fast flow chromatography, FPLC Resource 30Q, Resource Q and Mono Q chromatography. A single band was displayed on sodium dodecyl sulfate polyacrylamide gel electrophoresis, which corresponds to molecular weight of 14 600 daltons. The characteristic absorption was obtained at the wavelength 276 nm. The isoelectric point was about 5 1. It contained 18 amino acids and the 15 N terminal amino acid residues were LVGPIGAVGPAGKDG. It had a significant activity in stimulating liver to regenerate. Conclusion We obtained an unknown new active protein, that is hepatocyte regeneration stimulatory factor from shark liver (sHRSF).
