[Object]To providing new data for phylogenesis of Bangia atropurpurea by the sequencing of internal transcribed spacer（ITS region）of rDNA.[Method]B.atropurpurea was collected from Niangziguan Spring in Shanxi,the DN...[Object]To providing new data for phylogenesis of Bangia atropurpurea by the sequencing of internal transcribed spacer（ITS region）of rDNA.[Method]B.atropurpurea was collected from Niangziguan Spring in Shanxi,the DNA was extracted and the primers were designed for PCR amplification so as to obtain ITS gene sequence.[Result]The homology of ITS region between B.atropurpurea and Porphyra oligospermatangia was 75%,which was 79% between B.atropurpurea and P.yezoensis.[Conclusion]Compared with other genes,the ITS sequence had a greater evolution rate.The differences in classification and distribution resulted in the sequence diversity.展开更多
Sex determination and sex differentiation are important phenomena in fish, but the mechanisms of sex determination in Takifugu rubripes are poorly understood. In our study, the expression patterns of genes for DMRTs ...Sex determination and sex differentiation are important phenomena in fish, but the mechanisms of sex determination in Takifugu rubripes are poorly understood. In our study, the expression patterns of genes for DMRTs （DMRT1, DMRT2 and DMRT3）,sox9a and sox9b in T. rubripes tissues were verified with the Reverse Transcription （RT）-PCR detection. It is showed that DMRT1 expressions in testis and ovaries were much lower, and no expressions were fotmd in muscle, blood and tailfin. However, expressions for DMRT2 and DMRT3 were not found in the tissues stated above. Transcripts of sox9a were detected in muscle, fin, ovary and testis, but not in blood, whereas sox9b expression was only detected in ovary. The expression patterns of DMRTs, sox9a and sox9b in T. rubripes gonads suggest that these genes may not be sex-specific.展开更多
The constraint on the total energy in a given spatial region is given from holography by the mass of a black hole that just fits in that region, which leads to an UV/IR relation： the maximal energy density in that re...The constraint on the total energy in a given spatial region is given from holography by the mass of a black hole that just fits in that region, which leads to an UV/IR relation： the maximal energy density in that region is proportional to Mp^2/L^2, where Mp is the Planck mass and L is the spatial scale of that region under consideration. Assuming the maximal black hole in the universe is formed through gravitational collapse of perturbations in the universe, then the ＂Jeans＂ scale of the perturbations gives a causal connection scale RCC. For gravitational perturbations, RCC^-2= Max （H＋ 2H^2, -H） for a fiat universe. We study the cosmological dynamics of the corresponding vacuum energy density by choosing the causal connection scale as the IR cutoff in the UV/IR relation, in the cases of the vacuum energy density as an independently conserved energy component and an effective dynamical cosmological constant, respectively. It turns out that only the case with the choice RCC^-2 = H＋ 2H^2, could be consistent with the current cosmological observations when the vacuum density appears as an independently conserved energy component. In this case, the model is called holographic Ricci scalar dark energy model in the literature.展开更多
Heterostructures based on diverse two-dimensional(2D)materials are effective for tailoring and further promoting device performance and exhibit considerable potential in photodetection.However,the problem of high-dens...Heterostructures based on diverse two-dimensional(2D)materials are effective for tailoring and further promoting device performance and exhibit considerable potential in photodetection.However,the problem of high-density thermionic carriers can be hardly overcome in most reported heterostructure devices based on type I and type II band alignment,which leads to an unacceptably small Iphoto/Idark and strong temperature dependence that limit the performance of photodetectors.Here,using the MoTe_(2)/h-BN/MoTe_(2)/h-BN heterostructure,we report the hole-dominated Fowler–Nordheim quantum tunneling transport in both on and off states.The state-of-the-art device operating at room temperature shows high detectivity of>10^(8) Jones at a laser power density of<0.3 nW μm^(-2) from the visible to near infrared range.In addition,the fast on–off switching and highly sensitive photodetection properties promise superior imaging capabilities.The tunneling mechanism,in combination with other unique properties of 2D materials,is significant for novel photodetection.展开更多
The Sandage-Loeb （SL） test is a promising method for probing dark energy because it measures the redshift drift in the spectra of Lyman-o： forest of distant quasars, covering the ＂redshift desert＂ of 2 ≤ z ≤ 5,...The Sandage-Loeb （SL） test is a promising method for probing dark energy because it measures the redshift drift in the spectra of Lyman-o： forest of distant quasars, covering the ＂redshift desert＂ of 2 ≤ z ≤ 5, which is not covered by existing cosmological observations. Therefore, it could provide an important supplement to current cosmological observations. In this paper, we explore the impact of SL test on the precision of cosmological constraints for two typical holographic dark energy models, i.e., the original holographic dark energy （HDE） model and the Ricci holographic dark energy （RDE） model. To avoid data inconsistency, we use the best-fit models based on current combined observational data as the fiducial models to simulate 30 mock SL test data. The results show that SL test can effectively break the existing strong degeneracy between the present-day matter density Ωm0 and the Hubble constant 1-1o in other cosmological observations. For the considered two typical dark energy models, not only can a 30-year observation of SL test improve the constraint precision of Ωm0 and h dramatically, but can also enhance the constraint precision of the model parameters c and α significantly.展开更多
By phenomenologically describing the high-redshift star formation history, i.e., ,ρ.（z） oc [（1 ＋z）/4.5]-% and semi-analytically calculating the fractions of high-redshift Pop I/II and Pop II! stars, we investiga...By phenomenologically describing the high-redshift star formation history, i.e., ,ρ.（z） oc [（1 ＋z）/4.5]-% and semi-analytically calculating the fractions of high-redshift Pop I/II and Pop II! stars, we investigate the contributions from both high-redshfit Pop I/II and Pop II/stars to the observed near-infrared （3 μm 〈// 〈 5 μm） excess in the cosmic infrared background emission. In order to account for the observational level of the near-infrared excess, the power-law index or of the assumed star formation history is constrained to within the range of 0 ≤a≤1. Such a constraint is obtained under the condition that the viral temperature of dark matter halos belongs to the range of 500 K ≤ Tvir≤ 104 K.展开更多
Because gamma-ray bursts （GRBs） trace the high-z universe, there is an appreciable probability for a GRB to be gravitational lensed by galaxies in the universe. Herein we consider the gravitational lensing effect of...Because gamma-ray bursts （GRBs） trace the high-z universe, there is an appreciable probability for a GRB to be gravitational lensed by galaxies in the universe. Herein we consider the gravitational lensing effect of GRBs contributed by the dark matter halos in galaxies. Assuming that all halos have the singular isothermal sphere （SIS） mass profile in the mass range 101~h 1Mo 〈 M 〈 2×10^13h^-1M and all GRB samples follow the intrinsic redshift distribution and luminosity function derived from the Swift LGRBs sample, we calculated the gravitational lensing probability in BATSE, Swift/BAT and Fermi/GBM GRBs, re- spectively. With an derived probability result in BATSE GRBs, we searched for lensed GRB pairs in the BATSE5B GRB Spectral catalog. The search did not find any convincing gravitationally lensed events. We discuss our result and future obser- vations for GRB lensing observation.展开更多
基金Supported by National Science Foundation of China(30970187)~~
文摘[Object]To providing new data for phylogenesis of Bangia atropurpurea by the sequencing of internal transcribed spacer（ITS region）of rDNA.[Method]B.atropurpurea was collected from Niangziguan Spring in Shanxi,the DNA was extracted and the primers were designed for PCR amplification so as to obtain ITS gene sequence.[Result]The homology of ITS region between B.atropurpurea and Porphyra oligospermatangia was 75%,which was 79% between B.atropurpurea and P.yezoensis.[Conclusion]Compared with other genes,the ITS sequence had a greater evolution rate.The differences in classification and distribution resulted in the sequence diversity.
文摘Sex determination and sex differentiation are important phenomena in fish, but the mechanisms of sex determination in Takifugu rubripes are poorly understood. In our study, the expression patterns of genes for DMRTs （DMRT1, DMRT2 and DMRT3）,sox9a and sox9b in T. rubripes tissues were verified with the Reverse Transcription （RT）-PCR detection. It is showed that DMRT1 expressions in testis and ovaries were much lower, and no expressions were fotmd in muscle, blood and tailfin. However, expressions for DMRT2 and DMRT3 were not found in the tissues stated above. Transcripts of sox9a were detected in muscle, fin, ovary and testis, but not in blood, whereas sox9b expression was only detected in ovary. The expression patterns of DMRTs, sox9a and sox9b in T. rubripes gonads suggest that these genes may not be sex-specific.
基金supported in part by the Chinese Academy of Sciences under Grant No.KJCX3-SYW-N2National Natural Science Foundation of China under Grant Nos.10821504 and 10525060
文摘The constraint on the total energy in a given spatial region is given from holography by the mass of a black hole that just fits in that region, which leads to an UV/IR relation： the maximal energy density in that region is proportional to Mp^2/L^2, where Mp is the Planck mass and L is the spatial scale of that region under consideration. Assuming the maximal black hole in the universe is formed through gravitational collapse of perturbations in the universe, then the ＂Jeans＂ scale of the perturbations gives a causal connection scale RCC. For gravitational perturbations, RCC^-2= Max （H＋ 2H^2, -H） for a fiat universe. We study the cosmological dynamics of the corresponding vacuum energy density by choosing the causal connection scale as the IR cutoff in the UV/IR relation, in the cases of the vacuum energy density as an independently conserved energy component and an effective dynamical cosmological constant, respectively. It turns out that only the case with the choice RCC^-2 = H＋ 2H^2, could be consistent with the current cosmological observations when the vacuum density appears as an independently conserved energy component. In this case, the model is called holographic Ricci scalar dark energy model in the literature.
基金the funding by the National Natural Science Foundation of China(61704061 and 61974050)the financial support from the National Natural Science Foundation of China(11674119,11690030,and 11690032)+1 种基金the financial support from the National Natural Science Foundation of China(61905266)Shanghai Sailing Program(19YF1454600)。
文摘Heterostructures based on diverse two-dimensional(2D)materials are effective for tailoring and further promoting device performance and exhibit considerable potential in photodetection.However,the problem of high-density thermionic carriers can be hardly overcome in most reported heterostructure devices based on type I and type II band alignment,which leads to an unacceptably small Iphoto/Idark and strong temperature dependence that limit the performance of photodetectors.Here,using the MoTe_(2)/h-BN/MoTe_(2)/h-BN heterostructure,we report the hole-dominated Fowler–Nordheim quantum tunneling transport in both on and off states.The state-of-the-art device operating at room temperature shows high detectivity of>10^(8) Jones at a laser power density of<0.3 nW μm^(-2) from the visible to near infrared range.In addition,the fast on–off switching and highly sensitive photodetection properties promise superior imaging capabilities.The tunneling mechanism,in combination with other unique properties of 2D materials,is significant for novel photodetection.
基金supported by the Top-Notch Young Talents Program of Chinathe National Natural Science Foundation of China(Grant Nos.11175042,and 11522540)+1 种基金the Provincial Department of Education of Liaoning(Grant No.L2012087)the Fundamental Research Funds for the Central Universities(Grant Nos.N140505002,N140506002,and N140504007)
文摘The Sandage-Loeb （SL） test is a promising method for probing dark energy because it measures the redshift drift in the spectra of Lyman-o： forest of distant quasars, covering the ＂redshift desert＂ of 2 ≤ z ≤ 5, which is not covered by existing cosmological observations. Therefore, it could provide an important supplement to current cosmological observations. In this paper, we explore the impact of SL test on the precision of cosmological constraints for two typical holographic dark energy models, i.e., the original holographic dark energy （HDE） model and the Ricci holographic dark energy （RDE） model. To avoid data inconsistency, we use the best-fit models based on current combined observational data as the fiducial models to simulate 30 mock SL test data. The results show that SL test can effectively break the existing strong degeneracy between the present-day matter density Ωm0 and the Hubble constant 1-1o in other cosmological observations. For the considered two typical dark energy models, not only can a 30-year observation of SL test improve the constraint precision of Ωm0 and h dramatically, but can also enhance the constraint precision of the model parameters c and α significantly.
基金supported by the National Natural Science Foundation of China (Grant No.11103004)the Foundation for the Authors of National Excellent Doctoral Dissertations of China (Grant No.201225)
文摘By phenomenologically describing the high-redshift star formation history, i.e., ,ρ.（z） oc [（1 ＋z）/4.5]-% and semi-analytically calculating the fractions of high-redshift Pop I/II and Pop II! stars, we investigate the contributions from both high-redshfit Pop I/II and Pop II/stars to the observed near-infrared （3 μm 〈// 〈 5 μm） excess in the cosmic infrared background emission. In order to account for the observational level of the near-infrared excess, the power-law index or of the assumed star formation history is constrained to within the range of 0 ≤a≤1. Such a constraint is obtained under the condition that the viral temperature of dark matter halos belongs to the range of 500 K ≤ Tvir≤ 104 K.
基金supported by the National Basic Research Program of China(Grant No. 2014CB845800)the National Natural Science Foundation of China (Grant No. 11373012)
文摘Because gamma-ray bursts （GRBs） trace the high-z universe, there is an appreciable probability for a GRB to be gravitational lensed by galaxies in the universe. Herein we consider the gravitational lensing effect of GRBs contributed by the dark matter halos in galaxies. Assuming that all halos have the singular isothermal sphere （SIS） mass profile in the mass range 101~h 1Mo 〈 M 〈 2×10^13h^-1M and all GRB samples follow the intrinsic redshift distribution and luminosity function derived from the Swift LGRBs sample, we calculated the gravitational lensing probability in BATSE, Swift/BAT and Fermi/GBM GRBs, re- spectively. With an derived probability result in BATSE GRBs, we searched for lensed GRB pairs in the BATSE5B GRB Spectral catalog. The search did not find any convincing gravitationally lensed events. We discuss our result and future obser- vations for GRB lensing observation.
