A new record of the homalopsid snake, Gerarda prevostiana is presented from a mangrove-dominated patch in the vicinity of Kampung Bako, Sarawak, East Malaysia, and this comprises the first published record from the Su...A new record of the homalopsid snake, Gerarda prevostiana is presented from a mangrove-dominated patch in the vicinity of Kampung Bako, Sarawak, East Malaysia, and this comprises the first published record from the Sundaic Island of Borneo. A possible second locality for the species is a ca. 6.68 km site to its northeast, Kampung Buntal, based on an unlocated museum specimen. The species is widespread in mainland Southeast Asia, with additional records to the west （the Indian Subcontinent） and east （the Philippines Archipelago）, but was previously unrecorded from the islands of the Sundas. The secretive habits of the species, including the occupancy of mud lobster （Thalassinia spp.） mounds in mostly inaccessible, swampy habitats may be a reason for its perceived rarity and few published records.展开更多
While considerable progress has been made in the taxonomic studies of the genus Lycodon in Asia,questions remain to be clarified regarding the taxonomy of certain groups,particularly those containing species in China....While considerable progress has been made in the taxonomic studies of the genus Lycodon in Asia,questions remain to be clarified regarding the taxonomy of certain groups,particularly those containing species in China.Not only do many regions in China remain overlooked by herpetologists,resulting in the possibility of undiscovered new species,but the surveyed areas also have suspicious records of recognized congeners that require taxonomic confirmations.Combining both morphological and genetic data,we tackle these outstanding issues in the taxonomy of Lycodon in China.In particular,we discover two new species of Lycodon:one from the previously neglected hot-dry valley in the northern Hengduan Mountain Region close to Tibet,and another recluse and cryptic species from the L.fasciatus complex in the downtown park of a major city in southern Sichuan Province.Additionally,we clarify the distribution of L.septentrionalis in China and resurrect and elevate its junior synonym subspecies,Dinodon septentrionale chapaense,as a full,valid species,and we synonymize the recently described L.namdongensis to the resurrected L.chapaensis comb.nov..Lycodon chapaensis comb.nov.thus represents a new national record of reptilian fauna of China.Lastly,based on literature review,we also correct some of the erroneous records of L.fasciatus and L.ruhstrati in China,point out remaining taxonomic issues of the genus for future research,and update the dichotomous key and distribution of the 20 species of Lycodon currently recorded from China.展开更多
The taxaColuber nuthalli Theobald, 1868 andElaphis yunnanensis Anderson, 1879 are compared and re-described, based on the examination of their type material. The morphological similarities of these two taxa revealed t...The taxaColuber nuthalli Theobald, 1868 andElaphis yunnanensis Anderson, 1879 are compared and re-described, based on the examination of their type material. The morphological similarities of these two taxa revealed them as conspeciifc.Elaphis yunnanensis Anderson is thus declared as a protected name （nomen conservandum） with priority overC. nuthalli Theobald （nomen oblitum）. A lectotype forElaphis yunnanensis is designated and described. The validity ofyunnanensis as subspecies name in combination withOrthriophis taeniurus （Cope） will be discussed. A key to the subspecies ofO. taeniurus is provided.展开更多
Cross-sectional homogenization for full-core calculations of small and complex reactor configurations,such as research reactors,has been recently recognized as an interesting and challenging topic.This paper presents ...Cross-sectional homogenization for full-core calculations of small and complex reactor configurations,such as research reactors,has been recently recognized as an interesting and challenging topic.This paper presents the development of a PARCS/Serpent model for the neutronics analysis of a research reactor type TRIGA Mark-II loaded with Russian VVR-M2 fuel(known as the Dalat Nuclear Research Reactor or DNRR).The full-scale DNRR model and a supercell model for a shim/safety rod and its surrounding fuel bundles with the Monte Carlo code Serpent 2 were proposed to generate homogenized fewgroup cross sections for full-core diffusion calculations with PARCS.The full-scale DNRR model with Serpent 2 was also utilized as a reference to verify the PARCS/Serpent calculations.Comparison of the effective neutron multiplication factors,radial and axial core power distributions,and control rod worths showed a generally good agreement between PARCS and Serpent 2.In addition,the discrepancies between the PARCS and Serpent 2 results are also discussed.Consequently,the results indicate the applicability of the PARCS/Serpent model for further steady state and transient analyses of the DNRR.展开更多
To carry out accurate burnup calculations for a pebble-bed fluoride-salt-cooled high-temperature reactor,the energy-dependent cross-sectional model based on the Doppler broadening rejection correction method has been ...To carry out accurate burnup calculations for a pebble-bed fluoride-salt-cooled high-temperature reactor,the energy-dependent cross-sectional model based on the Doppler broadening rejection correction method has been proposed to develop the energy-dependent elastic scattering cross-sectional model. In this study, the Monte Carlo continuous energy code PSG2/Serpent was used to examine the difference between the constant cross-sectional model and the energy-dependent cross-sectional model during burnup. For the cases analyzed in this study,numerical simulations show that the multiplication coefficient was improved by hundreds pcm and ^(239)Pu concentration was improved by approximately 1–2% during burnup when the energy-dependent elastic scattering crosssectional model is considered.展开更多
Radiopharmaceuticals are used in nuclear medicine for diagnostic or therapeutic acts. The short decay half-lives of medical radioisotopes, especially those used for diagnostics, imply that they should be produced cont...Radiopharmaceuticals are used in nuclear medicine for diagnostic or therapeutic acts. The short decay half-lives of medical radioisotopes, especially those used for diagnostics, imply that they should be produced continuously and transported as quickly as possible to the medical units where they are used. Neutron-rich medical radioisotopes are generally produced in research reactors, like technetium-99m, lutetium-177, holmium-166 and iodine-131. On the other hand, proton-rich radioisotopes are produced via reactions with charged particles from accelerators like fluorine-18, gallium-67, iodine-123 and thallium-201. Beside this, innovative nuclear reactors are advocated as solutions to the issues of nuclear waste production and proliferation threats. Fast neutron, thorium-cycle and accelerator-driven subcritical (ADS) reactors are some of the most promising of them, proposed as safer fuel breeders and “waste burners”. This article examines the use of a fast thorium-cycle ADS with liquid lead-bismuth eutectic coolant for the production of molybdenum-99/technetium-99m and lutetium-177. Burnup simulation has been made with the Monte-Carlo (MC) code SERPENT. It is demonstrated that MC codes can advantageously be used to determine the optimal irradiation time for a given radioisotope in a realistic reactor core. It is also shown that fast thorium-cycle ADS is an economical option for the production of medical radioisotopes.展开更多
From the existing literature and data from museum specimens an overview is presented of all currently known terrestrial and semi-aquatic snakes of the Lesser Sunda Islands, in the Wallacean area of Indonesia. In total...From the existing literature and data from museum specimens an overview is presented of all currently known terrestrial and semi-aquatic snakes of the Lesser Sunda Islands, in the Wallacean area of Indonesia. In total, twenty-nine species are known to inhabit the area. Of these eight are endemic to the area： Boiga hoeseli, Coelognathus subradiatus, Dendrelaphis inornatus, Stegonotus florensis, Cylindrophis opisthorhodus, Broghammerus timoriensis, Liasis mackloti and Typhlops schmutzi. Insular endemism is only found at the subspecific level, including Liasis mackloti dunni （Wetar）, Liasis mackloti savuensis （Sawu）, Ramphotyphlops polygrammicus brongersmai （Sumba）, Ramphotyphlops polygrammicus elberti （Lombok） and Ramphotyphlops polygrammicus florensis （Flores）. Such endemism may be due to the relatively young geological age of the Lesser Sunda Islands and that the snake fauna is still underestimated. Taxonomy of the genus Cylindrophis, the species Coelognathus subradiatus, Dendrelaphis inornatus, Cryptelytrops insularis, and the five subspecies of Ramphotyphlops polygrammicus need to be reviewed. Ecological studies are urgently required to establish if the species Broghammerus timoriensis and Liasis mackloti savuensis are endangered and which conservation measures should be taken. Telah dilakukan pengamatan ulang dari kepustakaan yang ada, data dari databank Western Australian Museum, maupun koleksi museum. Hasil tersebut dirangkum dalam suam tinjauan mengenai semua jenis ular yang hidup di darat maupun di air-tawar dari daerah Nusa Tenggara sebagai bagian dari daerah Wallacea. Jumlah jenis yang dapat dipastikan berjumlah dua puluh sembilan jenis, dan delapan di antaranya merupakan jenis yang endemik, yaitu Boiga hoeseli, Coelognathus subradiatus, Dendrelaphis inornatus, Stegonotus florensis, Cylindrophis opisthorhodus, Broghammerus timoriensis, Liasis mackloti dan Typhlops schmutzi. Jenis endemic dalam daerah pulau hanya meliputi anak jenis： Liasis mackloti dunni （Wetar）, Liasis mackloti savuensis （Sawu）, RamphotyphIops polygrammicus brongersmai （Sumba）, Ramphotyphlops polygrammicus elberti （Lombok） dan Ramphotyphlops polygrammicus florensis （Flores）. Hal ini diperkirakan merupakan konsekuensi langsung dari sejarah geologi yang relatif singkat namun dapat juga disebabkan karena kekayaan jenis ular kurang dipelajari dengan lebih seksama. Kedudukan sistematik dari Coelognathus subradiatus, Dendrelaphis inornatus, Cylindrophis boulengeri, C. opisthorhodus, dan ke-lima subspecies Ramphotyphlops polygrammicus serta Cryptelytrops insularis perlu ditinjau kembali. Jenis-jenis yang diperkirakan terancam dan perlu perlindungan adalah jenis-jenis piton Broghammerus timoriensis dan Liasis maekloti savuensis. Penelitian ekologi perlu segara dilakukan untuk menentukan apakah jenis-jenis tersebut perlu perlindungan, dan juga tindakan konservasi yang mana bisa diambil.展开更多
This study presents a benchmark evaluation of the new ENDF/B-VIII.0 nuclear data library for the Organization for Economic Co-operation and Development/Nuclear Energy Agency Medium 1000 MWth sodium-cooled fast reactor...This study presents a benchmark evaluation of the new ENDF/B-VIII.0 nuclear data library for the Organization for Economic Co-operation and Development/Nuclear Energy Agency Medium 1000 MWth sodium-cooled fast reactor(SFR).The study presented herein covers both SFR core types,i.e.,metallic fueled(MET-1000)and oxide fueled(MOX-1000),simulated using the continuous-energy Monte Carlo Serpent2 code.The neutronics performances of the ENDF/B-VIII.0-based simulations were compared mainly to two libraries:ENDF/B-VII.1 and JENDL-4.0.The comparison includes several neutronics parameters evaluated for the beginning and end of the cycle conditions.These parameters include the effective multiplication factor keff,total effective delayed neutron fraction beff,sodium void reactivity(DqNa),Doppler constant(DqDoppler),and control rod worth(DqCR).In addition,a sensitivity study was used to reveal the major isotope/reaction pairs contributing to the discrepancy observed in the performance of the three libraries using 33 and 44-energy-group structures.展开更多
The conflict and congruity of dualistic approaches to the world inundate the illustration of agricultural production in the Pre-Columbian Art of the Maya.Crop production is co-dependent on human factors,environmental ...The conflict and congruity of dualistic approaches to the world inundate the illustration of agricultural production in the Pre-Columbian Art of the Maya.Crop production is co-dependent on human factors,environmental factors and animal factors.The symbiosis of these elements generated success or failure in harmony with the natural world.This paper explores the relationship of three animals to successful crop production with particular attention placed on the cane toad,as this creature has often been confused with frogs or underplayed in earlier academic research.The cane toad is a powerful force in organic farming,functioning as a deterrent to destructive pests.In addition,the cane toad produces powerful hallucinogenic substances for humans,while at the same time,repelling predators with its bitter taste,acrid smell and poison.This bufo-toxin is a powerful substance that links the toad with the Underworld origins of the maize.展开更多
The International Conference on Arginine and Pyrimidines （ICAP） had its origin as an arginine workshop organised by a group of microbiologists led by Werner Maas in 1972 （Rubio, 2003）. The shared requirement of ca...The International Conference on Arginine and Pyrimidines （ICAP） had its origin as an arginine workshop organised by a group of microbiologists led by Werner Maas in 1972 （Rubio, 2003）. The shared requirement of carbamoyl phosphate in both arginine and pyrimidine metabolism led to a natural association of researchers working in both fields.展开更多
基金the Sarawak Forest Department for issuance of a research permit(No.NCCD.907.4.4 Jld.7–39)a Fundamental Research Grant[Grant No:FRGS/07(04)787/2010(68)]from the Ministry of Higher Education of Malaysia for supporting our study on the herpetofauna of Sarawak.Y.M.
文摘A new record of the homalopsid snake, Gerarda prevostiana is presented from a mangrove-dominated patch in the vicinity of Kampung Bako, Sarawak, East Malaysia, and this comprises the first published record from the Sundaic Island of Borneo. A possible second locality for the species is a ca. 6.68 km site to its northeast, Kampung Buntal, based on an unlocated museum specimen. The species is widespread in mainland Southeast Asia, with additional records to the west （the Indian Subcontinent） and east （the Philippines Archipelago）, but was previously unrecorded from the islands of the Sundas. The secretive habits of the species, including the occupancy of mud lobster （Thalassinia spp.） mounds in mostly inaccessible, swampy habitats may be a reason for its perceived rarity and few published records.
基金This research is supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0501)Biodiversity Survey and Assessment Project of the Ministry of Ecology and Environment(2019HJ2096001006)+4 种基金China's Biodiversity Observation Network(Sino-BON),Southeast Asia Biodiversity Research Institute,CAS(Y4ZK111B01:2017CASSEABRIQG002)the Animal Branch of the Germplasm Bank of Wild Species,CAS(Large Research Infrastructure Funding)to J.C.and NSF GRFP 2017216966 to K.WWe thank Mr.Di-Hao Wu for providing locality information of the new speciesMr.Ben-Fu Miao,Mr.Hui-Ming Xu(Yunlong National Nature Reserve),and Mr.Wen-Jie Dong(KIZ)for their assistances in the fieldand Mr.Chao Wu,Mr.Wei-Liang Xie,Mr.Shao-Bing Hou(KIZ),Mr.Jin-Long Ren(CIB)and Mr.Franco Leung Ka Wah(CIB)for providing photos of Lycodon species.
文摘While considerable progress has been made in the taxonomic studies of the genus Lycodon in Asia,questions remain to be clarified regarding the taxonomy of certain groups,particularly those containing species in China.Not only do many regions in China remain overlooked by herpetologists,resulting in the possibility of undiscovered new species,but the surveyed areas also have suspicious records of recognized congeners that require taxonomic confirmations.Combining both morphological and genetic data,we tackle these outstanding issues in the taxonomy of Lycodon in China.In particular,we discover two new species of Lycodon:one from the previously neglected hot-dry valley in the northern Hengduan Mountain Region close to Tibet,and another recluse and cryptic species from the L.fasciatus complex in the downtown park of a major city in southern Sichuan Province.Additionally,we clarify the distribution of L.septentrionalis in China and resurrect and elevate its junior synonym subspecies,Dinodon septentrionale chapaense,as a full,valid species,and we synonymize the recently described L.namdongensis to the resurrected L.chapaensis comb.nov..Lycodon chapaensis comb.nov.thus represents a new national record of reptilian fauna of China.Lastly,based on literature review,we also correct some of the erroneous records of L.fasciatus and L.ruhstrati in China,point out remaining taxonomic issues of the genus for future research,and update the dichotomous key and distribution of the 20 species of Lycodon currently recorded from China.
基金Rufford foundation (UK) for financial support to his research
文摘The taxaColuber nuthalli Theobald, 1868 andElaphis yunnanensis Anderson, 1879 are compared and re-described, based on the examination of their type material. The morphological similarities of these two taxa revealed them as conspeciifc.Elaphis yunnanensis Anderson is thus declared as a protected name （nomen conservandum） with priority overC. nuthalli Theobald （nomen oblitum）. A lectotype forElaphis yunnanensis is designated and described. The validity ofyunnanensis as subspecies name in combination withOrthriophis taeniurus （Cope） will be discussed. A key to the subspecies ofO. taeniurus is provided.
基金the Ministry of Science and Technology of Vietnam(No.DTCB.06/18/VKHKTHN).
文摘Cross-sectional homogenization for full-core calculations of small and complex reactor configurations,such as research reactors,has been recently recognized as an interesting and challenging topic.This paper presents the development of a PARCS/Serpent model for the neutronics analysis of a research reactor type TRIGA Mark-II loaded with Russian VVR-M2 fuel(known as the Dalat Nuclear Research Reactor or DNRR).The full-scale DNRR model and a supercell model for a shim/safety rod and its surrounding fuel bundles with the Monte Carlo code Serpent 2 were proposed to generate homogenized fewgroup cross sections for full-core diffusion calculations with PARCS.The full-scale DNRR model with Serpent 2 was also utilized as a reference to verify the PARCS/Serpent calculations.Comparison of the effective neutron multiplication factors,radial and axial core power distributions,and control rod worths showed a generally good agreement between PARCS and Serpent 2.In addition,the discrepancies between the PARCS and Serpent 2 results are also discussed.Consequently,the results indicate the applicability of the PARCS/Serpent model for further steady state and transient analyses of the DNRR.
基金supported by the National Natural Science Foundation of China(Nos.11675057 and 11705195)the Hunan Provincial Education Department Project of China(No.15C1176)the General Financial Grant from the China Postdoctoral Science Foundation(No.2017M622697)
文摘To carry out accurate burnup calculations for a pebble-bed fluoride-salt-cooled high-temperature reactor,the energy-dependent cross-sectional model based on the Doppler broadening rejection correction method has been proposed to develop the energy-dependent elastic scattering cross-sectional model. In this study, the Monte Carlo continuous energy code PSG2/Serpent was used to examine the difference between the constant cross-sectional model and the energy-dependent cross-sectional model during burnup. For the cases analyzed in this study,numerical simulations show that the multiplication coefficient was improved by hundreds pcm and ^(239)Pu concentration was improved by approximately 1–2% during burnup when the energy-dependent elastic scattering crosssectional model is considered.
文摘Radiopharmaceuticals are used in nuclear medicine for diagnostic or therapeutic acts. The short decay half-lives of medical radioisotopes, especially those used for diagnostics, imply that they should be produced continuously and transported as quickly as possible to the medical units where they are used. Neutron-rich medical radioisotopes are generally produced in research reactors, like technetium-99m, lutetium-177, holmium-166 and iodine-131. On the other hand, proton-rich radioisotopes are produced via reactions with charged particles from accelerators like fluorine-18, gallium-67, iodine-123 and thallium-201. Beside this, innovative nuclear reactors are advocated as solutions to the issues of nuclear waste production and proliferation threats. Fast neutron, thorium-cycle and accelerator-driven subcritical (ADS) reactors are some of the most promising of them, proposed as safer fuel breeders and “waste burners”. This article examines the use of a fast thorium-cycle ADS with liquid lead-bismuth eutectic coolant for the production of molybdenum-99/technetium-99m and lutetium-177. Burnup simulation has been made with the Monte-Carlo (MC) code SERPENT. It is demonstrated that MC codes can advantageously be used to determine the optimal irradiation time for a given radioisotope in a realistic reactor core. It is also shown that fast thorium-cycle ADS is an economical option for the production of medical radioisotopes.
文摘From the existing literature and data from museum specimens an overview is presented of all currently known terrestrial and semi-aquatic snakes of the Lesser Sunda Islands, in the Wallacean area of Indonesia. In total, twenty-nine species are known to inhabit the area. Of these eight are endemic to the area： Boiga hoeseli, Coelognathus subradiatus, Dendrelaphis inornatus, Stegonotus florensis, Cylindrophis opisthorhodus, Broghammerus timoriensis, Liasis mackloti and Typhlops schmutzi. Insular endemism is only found at the subspecific level, including Liasis mackloti dunni （Wetar）, Liasis mackloti savuensis （Sawu）, Ramphotyphlops polygrammicus brongersmai （Sumba）, Ramphotyphlops polygrammicus elberti （Lombok） and Ramphotyphlops polygrammicus florensis （Flores）. Such endemism may be due to the relatively young geological age of the Lesser Sunda Islands and that the snake fauna is still underestimated. Taxonomy of the genus Cylindrophis, the species Coelognathus subradiatus, Dendrelaphis inornatus, Cryptelytrops insularis, and the five subspecies of Ramphotyphlops polygrammicus need to be reviewed. Ecological studies are urgently required to establish if the species Broghammerus timoriensis and Liasis mackloti savuensis are endangered and which conservation measures should be taken. Telah dilakukan pengamatan ulang dari kepustakaan yang ada, data dari databank Western Australian Museum, maupun koleksi museum. Hasil tersebut dirangkum dalam suam tinjauan mengenai semua jenis ular yang hidup di darat maupun di air-tawar dari daerah Nusa Tenggara sebagai bagian dari daerah Wallacea. Jumlah jenis yang dapat dipastikan berjumlah dua puluh sembilan jenis, dan delapan di antaranya merupakan jenis yang endemik, yaitu Boiga hoeseli, Coelognathus subradiatus, Dendrelaphis inornatus, Stegonotus florensis, Cylindrophis opisthorhodus, Broghammerus timoriensis, Liasis mackloti dan Typhlops schmutzi. Jenis endemic dalam daerah pulau hanya meliputi anak jenis： Liasis mackloti dunni （Wetar）, Liasis mackloti savuensis （Sawu）, RamphotyphIops polygrammicus brongersmai （Sumba）, Ramphotyphlops polygrammicus elberti （Lombok） dan Ramphotyphlops polygrammicus florensis （Flores）. Hal ini diperkirakan merupakan konsekuensi langsung dari sejarah geologi yang relatif singkat namun dapat juga disebabkan karena kekayaan jenis ular kurang dipelajari dengan lebih seksama. Kedudukan sistematik dari Coelognathus subradiatus, Dendrelaphis inornatus, Cylindrophis boulengeri, C. opisthorhodus, dan ke-lima subspecies Ramphotyphlops polygrammicus serta Cryptelytrops insularis perlu ditinjau kembali. Jenis-jenis yang diperkirakan terancam dan perlu perlindungan adalah jenis-jenis piton Broghammerus timoriensis dan Liasis maekloti savuensis. Penelitian ekologi perlu segara dilakukan untuk menentukan apakah jenis-jenis tersebut perlu perlindungan, dan juga tindakan konservasi yang mana bisa diambil.
基金the Research Institute of Science and Engineering at the University of Sharjah(No.1802040790-P).
文摘This study presents a benchmark evaluation of the new ENDF/B-VIII.0 nuclear data library for the Organization for Economic Co-operation and Development/Nuclear Energy Agency Medium 1000 MWth sodium-cooled fast reactor(SFR).The study presented herein covers both SFR core types,i.e.,metallic fueled(MET-1000)and oxide fueled(MOX-1000),simulated using the continuous-energy Monte Carlo Serpent2 code.The neutronics performances of the ENDF/B-VIII.0-based simulations were compared mainly to two libraries:ENDF/B-VII.1 and JENDL-4.0.The comparison includes several neutronics parameters evaluated for the beginning and end of the cycle conditions.These parameters include the effective multiplication factor keff,total effective delayed neutron fraction beff,sodium void reactivity(DqNa),Doppler constant(DqDoppler),and control rod worth(DqCR).In addition,a sensitivity study was used to reveal the major isotope/reaction pairs contributing to the discrepancy observed in the performance of the three libraries using 33 and 44-energy-group structures.
文摘The conflict and congruity of dualistic approaches to the world inundate the illustration of agricultural production in the Pre-Columbian Art of the Maya.Crop production is co-dependent on human factors,environmental factors and animal factors.The symbiosis of these elements generated success or failure in harmony with the natural world.This paper explores the relationship of three animals to successful crop production with particular attention placed on the cane toad,as this creature has often been confused with frogs or underplayed in earlier academic research.The cane toad is a powerful force in organic farming,functioning as a deterrent to destructive pests.In addition,the cane toad produces powerful hallucinogenic substances for humans,while at the same time,repelling predators with its bitter taste,acrid smell and poison.This bufo-toxin is a powerful substance that links the toad with the Underworld origins of the maize.
基金sponsored by MRC Functional Genomics Unit at the University of Oxford, the Journal of Genetics and Genomics, and Dutscher Scientific
文摘The International Conference on Arginine and Pyrimidines （ICAP） had its origin as an arginine workshop organised by a group of microbiologists led by Werner Maas in 1972 （Rubio, 2003）. The shared requirement of carbamoyl phosphate in both arginine and pyrimidine metabolism led to a natural association of researchers working in both fields.
