In brood-parasitic Cuculus cuckoos,male vocalizations are species-specific and easily distinguishable,whereas female calls are remarkably similar across species,making species identification challenging.In this study,...In brood-parasitic Cuculus cuckoos,male vocalizations are species-specific and easily distinguishable,whereas female calls are remarkably similar across species,making species identification challenging.In this study,we examined the structural characteristics and variability of female bubbling calls among four Cuculus species(Common Cuckoo C.canorus,Oriental Cuckoo C.optatus,Indian Cuckoo C.micropterus,and Lesser Cuckoo C.poliocephalus)breeding in South Korea.Comprehensive acoustic analyses of seven call parameters,using recordings from 2021 to 2023,were conducted to quantify the characteristics of their calls and compare withinand between-individual variability across species.Significant differences were found across all call parameters,with the Common Cuckoo producing the highest number of notes and the Oriental Cuckoo the lowest-frequency calls.Despite these differences,the overall structure of the calls remained acoustically similar,with overlapping characteristics across species.Furthermore,female Common Cuckoos exhibited greater within-individual variability in their calls,while the other species showed higher between-individual variability,which may further complicate species identification based vocalization alone.These findings highlight the complexities of female vocalizations in Cuculus cuckoos and suggest that ecological,social,and evolutionary factors may contribute to this vocal variability.展开更多
The effects of surface cleaning to eliminate the surface oxides formed on Cu seed layer with dilute H2SO4 solution were investigated. Cu seed layer formed on Ti/Si（100） wafer by sputter deposition was exposed to air...The effects of surface cleaning to eliminate the surface oxides formed on Cu seed layer with dilute H2SO4 solution were investigated. Cu seed layer formed on Ti/Si（100） wafer by sputter deposition was exposed to air to grow native Cu oxide. Dilute H2SO4 solutions and/or TS-40A alkaline soak cleaner were used to remove the native Cu-oxide. After mainly carbon groups （such as C=O） on surface of Cu seed layer were removed by pretreatment of TS-40A alkaline solution, subsequently, dilute H2SO4 acid solution removed Cu-oxides （Cu20 and CuO） as well as a lot of O=C and Cu（OH）2.展开更多
We made precipitated nano-ceria(~5 nm) on the surface of the catalyst by heat treatment of Cesupersaturated amorphous CeTiOxto improve the oxygen storage properties of CeO_2. The catalysts were prepared by sol-gel met...We made precipitated nano-ceria(~5 nm) on the surface of the catalyst by heat treatment of Cesupersaturated amorphous CeTiOxto improve the oxygen storage properties of CeO_2. The catalysts were prepared by sol-gel methods and TiO_2 nanoparticles were preferentially generated as a core material to form selective Ce-supersaturated structure on the catalyst surface. Reaction temperature and amount of doping element are optimized to induce selective crystallization of CeO_2. Cee Ce(2 nd shell)bond around 0.38 nm of Ce L3-edge extended X-ray absorption fine structure is reduced and nanostructure of precipitated ceria on the surface is observed by HREM. The catalyst is present as amorphous with precipitated nano-CeO_2 on the surface. The de-NOxefficiency of the catalyst, which has precipitated CeO_2, improves by ~50% owing to the simultaneous reactions of the nano CeO_2 and the amorphous CeTiO_x.展开更多
Many birds develop brood patches on their ventral apterium under hormonal regulation to effectively transmit body heat to eggs during incubation.The developed patch has several characteristics,including de-feathering,...Many birds develop brood patches on their ventral apterium under hormonal regulation to effectively transmit body heat to eggs during incubation.The developed patch has several characteristics,including de-feathering,vascularization,and edema.However,little is known about whether avian brood parasites that do not incubate their eggs exhibit brood patch development during the breeding season.In this study,we measured the size of the ventral apterium in 114 Common Cuckoos(Cuculus canorus)captured in the field throughout the breeding season and examined the appearance of the ventral apterium to confirm the development of brood patches.We also examined whether morphological traits and various factors correlated with the size of the ventral apterium(sternal apterium and abdominal apterium)and how it changed during the breeding season.We found no clear signs of brood patch development in Common Cuckoos captured throughout the breeding season,indicating that they likely did not develop brood patches on the ventral apterium during this period.We also found that ventral apterium size was positively correlated with wing length and body weight.In addition,Common Cuckoos with newly growing feathers on the boundary of the ventral apterium with pteryla were frequently observed as seasons progressed to the end.In conclusion,Common Cuckoos exhibit neither brood patch development nor the vestigial characteristics of ancestral brood patches,except for the growth of feathers on boundary the ventral apterium.Further studies examining brood patches across different groups of avian brood parasites are valuable for enhancing our understanding of the developmental and physiological adaptations of avian brood parasites.展开更多
Sperm competition has been studied in numerous species as a representative example of postcopulatory sexual selection,where sampling sperm from male is the most basic and important step.Sperm collection can be tricky ...Sperm competition has been studied in numerous species as a representative example of postcopulatory sexual selection,where sampling sperm from male is the most basic and important step.Sperm collection can be tricky in birds,however,because unlike mammals,the genitals of birds are generally latent in the cloacal region and their characteristics vary among species.Various methods to collect sperm from different birds have been tested,such as cloacal massage,feces collection,and electro-stimulation,but their applicability varies depending on species.In this study,we introduced the urodeum stimulation method(UroS method)to collect sperm from Cuculus cuckoos,such as the Common Cuckoo(C.canorus).These species are expected to have interesting patterns of pair bonding and sperm competition because of their unique breeding strategy called brood parasitism;however,it remains unexplored.In this study,we described the application of our new method to expel semen from male common cuckoos,measured the volume of semen collected,checked the presence of sperm in the semen sample,and finally estimated its success rate among 82 males.Samples were successfully collected from 76 cuckoos(approximately 93%)and the colors and volumes of the samples were very diverse.Sperm was present in 43 of these samples(57%),showing a sperm observation rate approximately twice as high as that of the conventional cloacal massage method.We believe that this novel method will contribute to a better understanding of postcopulatory sexual selection in avian brood parasites and facilitate the process of sperm collection and artificial insemination in other medium-sized birds.展开更多
As the 6th-Generation(6G)wireless communication networks evolve,privacy concerns are expected due to the transmission of vast amounts of security-sensitive private information.In this context,a Reconfigurable Intellig...As the 6th-Generation(6G)wireless communication networks evolve,privacy concerns are expected due to the transmission of vast amounts of security-sensitive private information.In this context,a Reconfigurable Intelligent Surface(RIS)emerges as a promising technology capable of enhancing transmission efficiency and strengthening information security.This study demonstrates how RISs can play a crucial role in making 6G networks more secure against eavesdropping attacks.We discuss the fundamentals and standardization aspects of RISs,along with an in-depth analysis of Physical-Layer Security(PLS).Our discussion centers on PLS design using RIS,highlighting aspects including beamforming,resource allocation,artificial noise,and cooperative communications.We also identify the research issues,propose potential solutions,and explore future perspectives.Finally,numerical results are provided to support our discussions and demonstrate the enhanced security enabled by RIS.展开更多
Osteochondral tissue is a highly specialized and complex tissue composed of articular cartilage and subchondral bone that are separated by a calcified cartilage interface.Multilayered or gradient scaffolds,often in co...Osteochondral tissue is a highly specialized and complex tissue composed of articular cartilage and subchondral bone that are separated by a calcified cartilage interface.Multilayered or gradient scaffolds,often in conjunction with stem cells and growth factors,have been developed to mimic the respective layers for osteochondral defect repair.In this study,we designed a hyaline cartilage-hypertrophic cartilage bilayer graft(RGD/RGDW)with chondrocytes.Previously,we demonstrated that RGD peptide-modified chondroitin sulfate cryogel(RGD group)is chondro-conductive and capable of hyaline cartilage formation.Here,we incorporated whitlockite(WH),a Mg^(2+)-containing calcium phosphate,into RGD cryogel(RGDW group)to induce chondrocyte hypertrophy and form collagen X-rich hypertrophic cartilage.This is the first study to use WH to produce hypertrophic cartilage.Chondrocytes-laden RGDW cryogel exhibited significantly upregulated expression of hypertrophy markers in vitro and formed ectopic hypertrophic cartilage in vivo,which mineralized into calcified cartilage in bone microenvironment.Subsequently,RGD cryogel and RGDW cryogel were combined into bilayer(RGD/RGDW group)and implanted into rabbit osteochondral defect,where RGD layer supports hyaline cartilage regeneration and bioceramic-containing RGDW layer promotes calcified cartilage formation.While the RGD group(monolayer)formed hyaline-like neotissue that extends into the subchondral bone,the RGD/RGDW group(bilayer)regenerated hyaline cartilage tissue confined to its respective layer and promoted osseointegration for integrative defect repair.展开更多
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by The Ministry of Education(NRF-2020R1I1A2063567)。
文摘In brood-parasitic Cuculus cuckoos,male vocalizations are species-specific and easily distinguishable,whereas female calls are remarkably similar across species,making species identification challenging.In this study,we examined the structural characteristics and variability of female bubbling calls among four Cuculus species(Common Cuckoo C.canorus,Oriental Cuckoo C.optatus,Indian Cuckoo C.micropterus,and Lesser Cuckoo C.poliocephalus)breeding in South Korea.Comprehensive acoustic analyses of seven call parameters,using recordings from 2021 to 2023,were conducted to quantify the characteristics of their calls and compare withinand between-individual variability across species.Significant differences were found across all call parameters,with the Common Cuckoo producing the highest number of notes and the Oriental Cuckoo the lowest-frequency calls.Despite these differences,the overall structure of the calls remained acoustically similar,with overlapping characteristics across species.Furthermore,female Common Cuckoos exhibited greater within-individual variability in their calls,while the other species showed higher between-individual variability,which may further complicate species identification based vocalization alone.These findings highlight the complexities of female vocalizations in Cuculus cuckoos and suggest that ecological,social,and evolutionary factors may contribute to this vocal variability.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 2012026094)
文摘The effects of surface cleaning to eliminate the surface oxides formed on Cu seed layer with dilute H2SO4 solution were investigated. Cu seed layer formed on Ti/Si（100） wafer by sputter deposition was exposed to air to grow native Cu oxide. Dilute H2SO4 solutions and/or TS-40A alkaline soak cleaner were used to remove the native Cu-oxide. After mainly carbon groups （such as C=O） on surface of Cu seed layer were removed by pretreatment of TS-40A alkaline solution, subsequently, dilute H2SO4 acid solution removed Cu-oxides （Cu20 and CuO） as well as a lot of O=C and Cu（OH）2.
基金Project supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)through GCRC-SOP(2011-0030013)
文摘We made precipitated nano-ceria(~5 nm) on the surface of the catalyst by heat treatment of Cesupersaturated amorphous CeTiOxto improve the oxygen storage properties of CeO_2. The catalysts were prepared by sol-gel methods and TiO_2 nanoparticles were preferentially generated as a core material to form selective Ce-supersaturated structure on the catalyst surface. Reaction temperature and amount of doping element are optimized to induce selective crystallization of CeO_2. Cee Ce(2 nd shell)bond around 0.38 nm of Ce L3-edge extended X-ray absorption fine structure is reduced and nanostructure of precipitated ceria on the surface is observed by HREM. The catalyst is present as amorphous with precipitated nano-CeO_2 on the surface. The de-NOxefficiency of the catalyst, which has precipitated CeO_2, improves by ~50% owing to the simultaneous reactions of the nano CeO_2 and the amorphous CeTiO_x.
基金financially supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by The Ministry of Education(NRF-2020R1I1A2063567)。
文摘Many birds develop brood patches on their ventral apterium under hormonal regulation to effectively transmit body heat to eggs during incubation.The developed patch has several characteristics,including de-feathering,vascularization,and edema.However,little is known about whether avian brood parasites that do not incubate their eggs exhibit brood patch development during the breeding season.In this study,we measured the size of the ventral apterium in 114 Common Cuckoos(Cuculus canorus)captured in the field throughout the breeding season and examined the appearance of the ventral apterium to confirm the development of brood patches.We also examined whether morphological traits and various factors correlated with the size of the ventral apterium(sternal apterium and abdominal apterium)and how it changed during the breeding season.We found no clear signs of brood patch development in Common Cuckoos captured throughout the breeding season,indicating that they likely did not develop brood patches on the ventral apterium during this period.We also found that ventral apterium size was positively correlated with wing length and body weight.In addition,Common Cuckoos with newly growing feathers on the boundary of the ventral apterium with pteryla were frequently observed as seasons progressed to the end.In conclusion,Common Cuckoos exhibit neither brood patch development nor the vestigial characteristics of ancestral brood patches,except for the growth of feathers on boundary the ventral apterium.Further studies examining brood patches across different groups of avian brood parasites are valuable for enhancing our understanding of the developmental and physiological adaptations of avian brood parasites.
基金financially supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by The Ministry of Education(NRF2020R1I1A2063567)。
文摘Sperm competition has been studied in numerous species as a representative example of postcopulatory sexual selection,where sampling sperm from male is the most basic and important step.Sperm collection can be tricky in birds,however,because unlike mammals,the genitals of birds are generally latent in the cloacal region and their characteristics vary among species.Various methods to collect sperm from different birds have been tested,such as cloacal massage,feces collection,and electro-stimulation,but their applicability varies depending on species.In this study,we introduced the urodeum stimulation method(UroS method)to collect sperm from Cuculus cuckoos,such as the Common Cuckoo(C.canorus).These species are expected to have interesting patterns of pair bonding and sperm competition because of their unique breeding strategy called brood parasitism;however,it remains unexplored.In this study,we described the application of our new method to expel semen from male common cuckoos,measured the volume of semen collected,checked the presence of sperm in the semen sample,and finally estimated its success rate among 82 males.Samples were successfully collected from 76 cuckoos(approximately 93%)and the colors and volumes of the samples were very diverse.Sperm was present in 43 of these samples(57%),showing a sperm observation rate approximately twice as high as that of the conventional cloacal massage method.We believe that this novel method will contribute to a better understanding of postcopulatory sexual selection in avian brood parasites and facilitate the process of sperm collection and artificial insemination in other medium-sized birds.
基金supported by Institute of Information&communications Technology Planning&Evaluation(IITP)grant funded by the Korea government(MSIT)(No.2020-0-00045,Development of movable high-capacity mobile communication infrastructure for telecommunication disaster and rescue)IITP grant funded by the Korea government(MSIT)(No.2021-0-00972,Development of intelligent wireless access technology)。
文摘As the 6th-Generation(6G)wireless communication networks evolve,privacy concerns are expected due to the transmission of vast amounts of security-sensitive private information.In this context,a Reconfigurable Intelligent Surface(RIS)emerges as a promising technology capable of enhancing transmission efficiency and strengthening information security.This study demonstrates how RISs can play a crucial role in making 6G networks more secure against eavesdropping attacks.We discuss the fundamentals and standardization aspects of RISs,along with an in-depth analysis of Physical-Layer Security(PLS).Our discussion centers on PLS design using RIS,highlighting aspects including beamforming,resource allocation,artificial noise,and cooperative communications.We also identify the research issues,propose potential solutions,and explore future perspectives.Finally,numerical results are provided to support our discussions and demonstrate the enhanced security enabled by RIS.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(NRF-2021K1A3A1A57086407,NRF-2021R1A2C2008821,NRF-2022R1I1A1A01071991)Arun Kumar Rajendran was supported by the National Research Foundation of Korea(NRF)grant Brain Pool program funded by the Ministry of Science and ICT through the National Research Foundation of Korea(2020H1D3A1A04081286)The Institute of Engineering Research at Seoul National University provided research facilities,and additional support came from the SNU Engineering-Medicine Collaboration grant.
文摘Osteochondral tissue is a highly specialized and complex tissue composed of articular cartilage and subchondral bone that are separated by a calcified cartilage interface.Multilayered or gradient scaffolds,often in conjunction with stem cells and growth factors,have been developed to mimic the respective layers for osteochondral defect repair.In this study,we designed a hyaline cartilage-hypertrophic cartilage bilayer graft(RGD/RGDW)with chondrocytes.Previously,we demonstrated that RGD peptide-modified chondroitin sulfate cryogel(RGD group)is chondro-conductive and capable of hyaline cartilage formation.Here,we incorporated whitlockite(WH),a Mg^(2+)-containing calcium phosphate,into RGD cryogel(RGDW group)to induce chondrocyte hypertrophy and form collagen X-rich hypertrophic cartilage.This is the first study to use WH to produce hypertrophic cartilage.Chondrocytes-laden RGDW cryogel exhibited significantly upregulated expression of hypertrophy markers in vitro and formed ectopic hypertrophic cartilage in vivo,which mineralized into calcified cartilage in bone microenvironment.Subsequently,RGD cryogel and RGDW cryogel were combined into bilayer(RGD/RGDW group)and implanted into rabbit osteochondral defect,where RGD layer supports hyaline cartilage regeneration and bioceramic-containing RGDW layer promotes calcified cartilage formation.While the RGD group(monolayer)formed hyaline-like neotissue that extends into the subchondral bone,the RGD/RGDW group(bilayer)regenerated hyaline cartilage tissue confined to its respective layer and promoted osseointegration for integrative defect repair.
