Location-based services have become an important part of the daily life.Fingerprint localization has been put forward to overcome the shortcomings of the traditional positioning algorithms in indoor scenario and rich ...Location-based services have become an important part of the daily life.Fingerprint localization has been put forward to overcome the shortcomings of the traditional positioning algorithms in indoor scenario and rich scattering environment.In this paper,a single-site multiple-input multiple-output(MIMO)orthogonal frequency division multiplexing(OFDM)system is modeled,from which an angle delay channel power matrix(ADCPM)is extracted.Considering the changing environment,auto encoders are used to generate new fingerprints based on ADCPM fingerprints to improve the robustness of the fingerprints.When the scattering environment has changed beyond a certain extent,the robustness will not be able to make up for the positioning error.Under this circumstance,an updating of the fingerprint database is imperative.A new fingerprint database updating algorithm which combines a new clustering method and an updating rule based on probability is proposed.Simulation results show the desirable performance of the proposed methods.展开更多
Nitrogen deposition is an important means of exogenous nitrogen input in reservoir water.Agricultural activities around the reservoir lead to a sharp increase in the concentration of ammonia in the atmosphere,which po...Nitrogen deposition is an important means of exogenous nitrogen input in reservoir water.Agricultural activities around the reservoir lead to a sharp increase in the concentration of ammonia in the atmosphere,which poses a threat to the reservoir water body.Clarifying the contribution of agricultural ammonia release to atmospheric NH_(x)(gaseous NH_(3)and particulate NH_(4)^(+)),in the reservoir area can provide a theoretical foundation for local reactive nitrogen control.We collected atmospheric NH_(3)and NH_(4)^(+)samples during the agricultural periods and analyzed the isotopic characteristics of atmospheric NH_(x)and the contribution rates of different ammonia sources in the Xichuan area of the Danjiangkou Reservoir.The results showed that the initialδ~(15)N values of NH_(3)(-30.0‰to–7.2‰)and particulate NH_(4)^(+)(–33‰to+4.9‰for finer and coarser particles,respectively)are different,and their contribution ratios from dissimilar ammonia sources are also different,among which NH_(4)^(+)is more susceptible to meteorological factors.However,since the atmospheric NH_(x)in the Xichuan area is mainly gaseous NH_(3),the final sources of atmospheric ammonia nitrogen source depend on gaseous NH_(3).Agricultural sources(59%-74%)were the main NH_(3)sources in this area.Among them,the fertilizer use emission was dominant;it had the highest contribution rate in summer during the agricultural period and a more prominent impact in areas with less human interference.Reasonable regulation of the application of high-ammonia releasing fertilizer,especially during the agricultural period in summer,is an effective way to reduce the threat of atmospheric ammonia to water health.展开更多
The evolution of heteromorphic sex chromosomes shall lead to gene expression dosage problems,as in at least one of the sexes,the sex-linked gene dose has been reduced by half.It has been proposed that the transcriptio...The evolution of heteromorphic sex chromosomes shall lead to gene expression dosage problems,as in at least one of the sexes,the sex-linked gene dose has been reduced by half.It has been proposed that the transcriptional output of the whole X or Z chromosome should be doubled for complete dosage compensation in heterogametic sex.However,owing to the variability of the existing methods to determine the transcriptional differences between sex chromosomes and autosomes(S:A ratios)in different studies,we collected more than 500 public RNA-Seq data set from multiple tissues and species in major clades and proposed a unified computational framework for unbiased and comparable measurement of the S:A ratios of multiple species.We also tested the evolution of dosage compensation more directly by assessing changes in the expression levels of the current sex-linked genes relative to those of the ancestral sex-linked genes.We found that in mammals and birds,the S:A ratio is approximately 0.5,whereas in insects,fishes,and flatworms,the S:A ratio is approximately 1.0.Further analysis showed that the fraction of dosage-sensitive housekeeping genes on the X/Z chromosome is significantly correlated with the S:A ratio.In addition,the degree of degeneration of the Y chromosome may be responsible for the change in the S:A ratio in mammals without a dosage compensation mechanism.Our observations offer unequivocal support for the sex chromosome insensitivity hypothesis in animals and suggest that dosage sensitivity states of sex chromosomes are a major factor underlying different evolutionary strategies of dosage compensation.展开更多
The secondary structure is a fundamental feature of both non-coding RNAs(ncRNAs)and messenger RNAs(mRNAs).However,our understanding of the secondary structures of mRNAs,especially those of the coding regions,remains e...The secondary structure is a fundamental feature of both non-coding RNAs(ncRNAs)and messenger RNAs(mRNAs).However,our understanding of the secondary structures of mRNAs,especially those of the coding regions,remains elusive,likely due to translation and the lack of RNA-binding proteins that sustain the consensus structure like those binding to ncRNAs.Indeed,mRNAs have recently been found to adopt diverse alternative structures,but the overall functional significance remains untested.We hereby approach this problem by estimating the folding specificity,i.e.,the probability that a fragment of an mRNA folds back to the same partner once refolded.We show that the folding specificity of mRNAs is lower than that of ncRNAs and exhibits moderate evolutionary conservation.Notably,we find that specific rather than alternative folding is likely evolutionarily adaptive since specific folding is frequently associated with functionally important genes or sites within a gene.Additional analysis in combination with ribosome density suggests the ability to modulate ribosome movement as one potential functional advantage provided by specific folding.Our findings reveal a novel facet of the RNA structurome with important functional and evolutionary implications and indicate a potential method for distinguishing the mRNA secondary structures maintained by natural selection from molecular noise.展开更多
基金supported by Jiangsu Province Key Research and Development Program(BE2018704)Technical Innovation Project of The Ministry of Public Security(20170001)+1 种基金Fundamental Research Funds for the Central Universities(2242022k30001)National Science Foundation of China(CN)(Grant No.61871111).
文摘Location-based services have become an important part of the daily life.Fingerprint localization has been put forward to overcome the shortcomings of the traditional positioning algorithms in indoor scenario and rich scattering environment.In this paper,a single-site multiple-input multiple-output(MIMO)orthogonal frequency division multiplexing(OFDM)system is modeled,from which an angle delay channel power matrix(ADCPM)is extracted.Considering the changing environment,auto encoders are used to generate new fingerprints based on ADCPM fingerprints to improve the robustness of the fingerprints.When the scattering environment has changed beyond a certain extent,the robustness will not be able to make up for the positioning error.Under this circumstance,an updating of the fingerprint database is imperative.A new fingerprint database updating algorithm which combines a new clustering method and an updating rule based on probability is proposed.Simulation results show the desirable performance of the proposed methods.
基金supported by the National Natural Science Foundation of China (Nos.U1704241 and 42007175)the Plan for Scientific Innovation Talent of Henan Province (No.194200510010)the Science Research Funds for the Universities of Henan Province (No.NSFRF200326)。
文摘Nitrogen deposition is an important means of exogenous nitrogen input in reservoir water.Agricultural activities around the reservoir lead to a sharp increase in the concentration of ammonia in the atmosphere,which poses a threat to the reservoir water body.Clarifying the contribution of agricultural ammonia release to atmospheric NH_(x)(gaseous NH_(3)and particulate NH_(4)^(+)),in the reservoir area can provide a theoretical foundation for local reactive nitrogen control.We collected atmospheric NH_(3)and NH_(4)^(+)samples during the agricultural periods and analyzed the isotopic characteristics of atmospheric NH_(x)and the contribution rates of different ammonia sources in the Xichuan area of the Danjiangkou Reservoir.The results showed that the initialδ~(15)N values of NH_(3)(-30.0‰to–7.2‰)and particulate NH_(4)^(+)(–33‰to+4.9‰for finer and coarser particles,respectively)are different,and their contribution ratios from dissimilar ammonia sources are also different,among which NH_(4)^(+)is more susceptible to meteorological factors.However,since the atmospheric NH_(x)in the Xichuan area is mainly gaseous NH_(3),the final sources of atmospheric ammonia nitrogen source depend on gaseous NH_(3).Agricultural sources(59%-74%)were the main NH_(3)sources in this area.Among them,the fertilizer use emission was dominant;it had the highest contribution rate in summer during the agricultural period and a more prominent impact in areas with less human interference.Reasonable regulation of the application of high-ammonia releasing fertilizer,especially during the agricultural period in summer,is an effective way to reduce the threat of atmospheric ammonia to water health.
基金supported by grants from the National Key R&D Program of China(2017YFA0103504 to X.C.and project number:2018ZX10301402 awarded to J.-R.Y.)the National Natural Science Foundation of China(project numbers:31771406 awarded to X.C.and 31671320,31871320,and 81830103 awarded to J.-R.Y.)
文摘The evolution of heteromorphic sex chromosomes shall lead to gene expression dosage problems,as in at least one of the sexes,the sex-linked gene dose has been reduced by half.It has been proposed that the transcriptional output of the whole X or Z chromosome should be doubled for complete dosage compensation in heterogametic sex.However,owing to the variability of the existing methods to determine the transcriptional differences between sex chromosomes and autosomes(S:A ratios)in different studies,we collected more than 500 public RNA-Seq data set from multiple tissues and species in major clades and proposed a unified computational framework for unbiased and comparable measurement of the S:A ratios of multiple species.We also tested the evolution of dosage compensation more directly by assessing changes in the expression levels of the current sex-linked genes relative to those of the ancestral sex-linked genes.We found that in mammals and birds,the S:A ratio is approximately 0.5,whereas in insects,fishes,and flatworms,the S:A ratio is approximately 1.0.Further analysis showed that the fraction of dosage-sensitive housekeeping genes on the X/Z chromosome is significantly correlated with the S:A ratio.In addition,the degree of degeneration of the Y chromosome may be responsible for the change in the S:A ratio in mammals without a dosage compensation mechanism.Our observations offer unequivocal support for the sex chromosome insensitivity hypothesis in animals and suggest that dosage sensitivity states of sex chromosomes are a major factor underlying different evolutionary strategies of dosage compensation.
基金supported by the National Key Technology R&D Program of China(Grant Nos.2017YFA0103504 to XC,2018ZX10301402 to JRY)the National Natural Science Foundation of China(Grant Nos.31671320,31871320,and 81830103 to JRY)the start-up grants from the“100 Top Talents Program”of Sun Yat-sen University,China(Grant Nos.50000-18821112 to XC,50000-18821117 to JRY).
文摘The secondary structure is a fundamental feature of both non-coding RNAs(ncRNAs)and messenger RNAs(mRNAs).However,our understanding of the secondary structures of mRNAs,especially those of the coding regions,remains elusive,likely due to translation and the lack of RNA-binding proteins that sustain the consensus structure like those binding to ncRNAs.Indeed,mRNAs have recently been found to adopt diverse alternative structures,but the overall functional significance remains untested.We hereby approach this problem by estimating the folding specificity,i.e.,the probability that a fragment of an mRNA folds back to the same partner once refolded.We show that the folding specificity of mRNAs is lower than that of ncRNAs and exhibits moderate evolutionary conservation.Notably,we find that specific rather than alternative folding is likely evolutionarily adaptive since specific folding is frequently associated with functionally important genes or sites within a gene.Additional analysis in combination with ribosome density suggests the ability to modulate ribosome movement as one potential functional advantage provided by specific folding.Our findings reveal a novel facet of the RNA structurome with important functional and evolutionary implications and indicate a potential method for distinguishing the mRNA secondary structures maintained by natural selection from molecular noise.