FeSiBCuNb/FeNi composite magnetic powder cores(CMPCs)with outstanding high-frequency permeability and low core loss(P_(cv))have been developed by hybridizing HNO 3-passivated Fe_(73.5)Cu_(1)Nb_(3)Si_(13.5)B_(9) nanocr...FeSiBCuNb/FeNi composite magnetic powder cores(CMPCs)with outstanding high-frequency permeability and low core loss(P_(cv))have been developed by hybridizing HNO 3-passivated Fe_(73.5)Cu_(1)Nb_(3)Si_(13.5)B_(9) nanocrystalline powder with finer Fe 50Ni 50 powder.A 7 wt.%HNO 3 passivation treatment forms a Fe_(3)O_(4)-dominant oxidation layer on the nanocrystalline powder surface,which increases its electrical resistivity and reduces the P_(cv) of the power cores.As FeNi content increases from 0 to 40 wt.%,the porosity of the CMPCs decreases consistently,while saturation magnetization(M_(s)),effective permeability(μ_(e)),and P_(cv) gradually enhance.An appropriate increase in compaction pressure further decreases the porosity and leads to enhanced M s,μe,and lowered P_(cv).The CMPC with 40 wt.%FeNi,compacted at 1000 MPa,exhibits the best comprehensive soft magnetic properties with M s,μe,and P_(cv) at 50 mT/200 kHz of 136.3 emu/g,57.4,and 599 mW/cm^(3),respectively.The improved M_(s) andμe result from the reduced porosity combined with the FeNi’s inherently higher M_(s) and μ_(e).The increased high-frequency P_(cv) after FeNi addition mainly arises from the raised eddy loss due to decreased electrical resistivity.The reduced P_(cv) through the optimal compaction pressure is due to the further elimination of pore defects in the CMPCs.展开更多
The effect of combined levonorgestrel(P)and quinestrol(E)on the fertility of stripedfield mouse(Apodemus agrarius)has not been evaluated.We performed a series of experiments in both the laboratory andfield to assess the...The effect of combined levonorgestrel(P)and quinestrol(E)on the fertility of stripedfield mouse(Apodemus agrarius)has not been evaluated.We performed a series of experiments in both the laboratory andfield to assess the effect of P and/or E on the fertility of A.agrarius.In the laboratory,to test the time-dependent anti-fertility ef-fects of P and E,as well as their mixtures,90 male stripedfield mice were randomly assigned to 6 treatment groups(n=60),and a control group(n=30).Mice in 3 treatment groups were administered 1 of the 3 compounds(1 mg�kg–1[body weight]EP-1,0.34 mg�kg–1 E,0.66 mg�kg–1 P)for 3 successive days(another half for 7 suc-cessive days)via oral gavage;mice were then sacrificed 15 and 45 days after initiating the gavage treatment.Ourfindings indicated that E and EP-1 treatment,but not P or control treatment,significantly decreased the sperm count in the caudal epididymis,as well as the weight of the testes,epididymides,and seminal vesicles.Additionally,fer-tile female mice mated with E-and EP-1-treated males produced smaller pups.These data indicate that E and EP-1 can induce infertility in male A.agrarius.In thefield,the population density of A.agrarius was significantly influ-enced by EP-1,and the rodent density in the treatment group was lower than that in the control group.Overall,our results indicate that EP-1 is an effective contraceptive in A.agrarius,a dominant rodent species in the farmland.展开更多
Animal-mediated seed dispersal is an important ecological process in which a strong mutualism between animals and plants can arise.However,few studies have examined how a community of potential seed dispersers interac...Animal-mediated seed dispersal is an important ecological process in which a strong mutualism between animals and plants can arise.However,few studies have examined how a community of potential seed dispersers interacts with sympatric seed trees.We employed a series of experiments in the Qinling Mountains in both semi-natural enclosure and the field to assess the interactions among 3 sympatric rodent species and 3 Fagaceae tree seeds.Seed traits all showed similar tannin levels but markedly different physical traits and nutritional contents.We found that seeds with heavy weight,thick coat,and high nutritional contents were less likely to be eaten in situ but more often to be eaten after dispersal or hoarded by rodents.These results support both the handling time hypothesis and the high nutrition hypothesis.Surprisingly,we also found that rodents,maybe,preferred to consume seeds with low levels of crude fiber in situ,and to harvest and hoard those with high levels of crude fiber for later consumption.The sympatric rodent species,Cansumys canus,the largest rodent in our study,harvested and hoarded more Quercus variabilis seeds with high physical and nutritional traits,while Apodemus draco,the smallest rodent,harvested more Q.serrata seeds with low physical and nutritional traits,and Niviventer confucianus harvested and hoarded more Q.aliena seeds with medium physical and nutritional traits.Our study demonstrates that different seed traits play different roles in influencing the seed fate and the shaping of mutualism and predation interactions within a community of rodent species.展开更多
With the overuse of antibiotics in health care and animal husbandry,antibiotic resistance becomes a serious threat to public health.Antibiotic residues from veterinarymedicine have increased the dissemination of antib...With the overuse of antibiotics in health care and animal husbandry,antibiotic resistance becomes a serious threat to public health.Antibiotic residues from veterinarymedicine have increased the dissemination of antibiotic resistance genes(ARGs)by horizontal gene transfer globally,leading to the enrichment of ARGs in wildlife.Plateau pika(Ochotona curzoniae)is a small herbivore endemic to the Qinghai–Tibetan Plateau.Previous studies reveal that pika evolves a coprophagy behavior toward cohabitated yak,which makes the pika population a potential reservoir of ARGs.Yet,little is known about the resistome of pika under different grazing intensities.Here,we sampled the cecum content of pika from three different grazing intensity areas in the Qinghai–Tibetan Plateau to evaluate the effect of grazing on its gut microbiota and resistome.By using the 16S full-length amplicon and metagenomic sequencing,our study revealed that livestock grazing significantly altered the gut microbial community of plateau pika as compared to prohibited grazing areas.We found bacterial lineage Prevotellaceae,Lachnospirales,and RF39 increased in grazing areas.Analysis of the resistome revealed that pika from continuous grazing areas enriched a higher abundance of colistin(MCR)and streptogramin(vat)resistance genes.Moreover,we observed significant correlations between the gut microbial community,ARGs,and mobile genetic element profiles,hinting that pika gut microbiota was an important shaping force of the resistome.In future studies,the continuous monitoring of wildlife gut resistome and environmental antibiotic residues is imperative for a better understanding and for tackling the horizontal gene transfer of ARGs across the wildlife–livestock interface.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB3804100)the National Natural Science Foundation of China(Grant Nos.52171153,and 52371149).
文摘FeSiBCuNb/FeNi composite magnetic powder cores(CMPCs)with outstanding high-frequency permeability and low core loss(P_(cv))have been developed by hybridizing HNO 3-passivated Fe_(73.5)Cu_(1)Nb_(3)Si_(13.5)B_(9) nanocrystalline powder with finer Fe 50Ni 50 powder.A 7 wt.%HNO 3 passivation treatment forms a Fe_(3)O_(4)-dominant oxidation layer on the nanocrystalline powder surface,which increases its electrical resistivity and reduces the P_(cv) of the power cores.As FeNi content increases from 0 to 40 wt.%,the porosity of the CMPCs decreases consistently,while saturation magnetization(M_(s)),effective permeability(μ_(e)),and P_(cv) gradually enhance.An appropriate increase in compaction pressure further decreases the porosity and leads to enhanced M s,μe,and lowered P_(cv).The CMPC with 40 wt.%FeNi,compacted at 1000 MPa,exhibits the best comprehensive soft magnetic properties with M s,μe,and P_(cv) at 50 mT/200 kHz of 136.3 emu/g,57.4,and 599 mW/cm^(3),respectively.The improved M_(s) andμe result from the reduced porosity combined with the FeNi’s inherently higher M_(s) and μ_(e).The increased high-frequency P_(cv) after FeNi addition mainly arises from the raised eddy loss due to decreased electrical resistivity.The reduced P_(cv) through the optimal compaction pressure is due to the further elimination of pore defects in the CMPCs.
基金supported by the Science and Technology Program of Shaanxi Academy of Sciences(2017K-11,2018k-04,2020k-21)the international Partnership of Chinese Academy of Sciences(Grant No.152111KYSB20160089)+2 种基金the Key Research and Development Program of Shaanxi(2018NY-135,2021NY-042)the Science and Technology Innovation Program of Shaanxi Academy of Forestry(SXLK2020-0209)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,2019QZKK0501).
文摘The effect of combined levonorgestrel(P)and quinestrol(E)on the fertility of stripedfield mouse(Apodemus agrarius)has not been evaluated.We performed a series of experiments in both the laboratory andfield to assess the effect of P and/or E on the fertility of A.agrarius.In the laboratory,to test the time-dependent anti-fertility ef-fects of P and E,as well as their mixtures,90 male stripedfield mice were randomly assigned to 6 treatment groups(n=60),and a control group(n=30).Mice in 3 treatment groups were administered 1 of the 3 compounds(1 mg�kg–1[body weight]EP-1,0.34 mg�kg–1 E,0.66 mg�kg–1 P)for 3 successive days(another half for 7 suc-cessive days)via oral gavage;mice were then sacrificed 15 and 45 days after initiating the gavage treatment.Ourfindings indicated that E and EP-1 treatment,but not P or control treatment,significantly decreased the sperm count in the caudal epididymis,as well as the weight of the testes,epididymides,and seminal vesicles.Additionally,fer-tile female mice mated with E-and EP-1-treated males produced smaller pups.These data indicate that E and EP-1 can induce infertility in male A.agrarius.In thefield,the population density of A.agrarius was significantly influ-enced by EP-1,and the rodent density in the treatment group was lower than that in the control group.Overall,our results indicate that EP-1 is an effective contraceptive in A.agrarius,a dominant rodent species in the farmland.
基金Funds were provided by the National Natural Science Foundation of China(32172436,31901085,31100283)the Shaanxi Natural Science Foundation(2021JQ-841)+3 种基金the Shaanxi Key Research and Development Program(2021NY-042)the Science and Technology Program of Shaanxi Academy of Sciences(2018K-04,2020K-21)the Science and Technology Innovation Program of Shaanxi Academy of Forestry(SXLK2020-0209)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,2019QZKK0501).
文摘Animal-mediated seed dispersal is an important ecological process in which a strong mutualism between animals and plants can arise.However,few studies have examined how a community of potential seed dispersers interacts with sympatric seed trees.We employed a series of experiments in the Qinling Mountains in both semi-natural enclosure and the field to assess the interactions among 3 sympatric rodent species and 3 Fagaceae tree seeds.Seed traits all showed similar tannin levels but markedly different physical traits and nutritional contents.We found that seeds with heavy weight,thick coat,and high nutritional contents were less likely to be eaten in situ but more often to be eaten after dispersal or hoarded by rodents.These results support both the handling time hypothesis and the high nutrition hypothesis.Surprisingly,we also found that rodents,maybe,preferred to consume seeds with low levels of crude fiber in situ,and to harvest and hoard those with high levels of crude fiber for later consumption.The sympatric rodent species,Cansumys canus,the largest rodent in our study,harvested and hoarded more Quercus variabilis seeds with high physical and nutritional traits,while Apodemus draco,the smallest rodent,harvested more Q.serrata seeds with low physical and nutritional traits,and Niviventer confucianus harvested and hoarded more Q.aliena seeds with medium physical and nutritional traits.Our study demonstrates that different seed traits play different roles in influencing the seed fate and the shaping of mutualism and predation interactions within a community of rodent species.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,2019QZKK0501)the National Natural Science Foundation of China(32172436)the Science and Technology Program of Shaanxi Academy of Science(2022K-16).
文摘With the overuse of antibiotics in health care and animal husbandry,antibiotic resistance becomes a serious threat to public health.Antibiotic residues from veterinarymedicine have increased the dissemination of antibiotic resistance genes(ARGs)by horizontal gene transfer globally,leading to the enrichment of ARGs in wildlife.Plateau pika(Ochotona curzoniae)is a small herbivore endemic to the Qinghai–Tibetan Plateau.Previous studies reveal that pika evolves a coprophagy behavior toward cohabitated yak,which makes the pika population a potential reservoir of ARGs.Yet,little is known about the resistome of pika under different grazing intensities.Here,we sampled the cecum content of pika from three different grazing intensity areas in the Qinghai–Tibetan Plateau to evaluate the effect of grazing on its gut microbiota and resistome.By using the 16S full-length amplicon and metagenomic sequencing,our study revealed that livestock grazing significantly altered the gut microbial community of plateau pika as compared to prohibited grazing areas.We found bacterial lineage Prevotellaceae,Lachnospirales,and RF39 increased in grazing areas.Analysis of the resistome revealed that pika from continuous grazing areas enriched a higher abundance of colistin(MCR)and streptogramin(vat)resistance genes.Moreover,we observed significant correlations between the gut microbial community,ARGs,and mobile genetic element profiles,hinting that pika gut microbiota was an important shaping force of the resistome.In future studies,the continuous monitoring of wildlife gut resistome and environmental antibiotic residues is imperative for a better understanding and for tackling the horizontal gene transfer of ARGs across the wildlife–livestock interface.
