Let F be a distribution function supported on (-∞,∞) with a finite mean μ. In this note we show that if its tail F = 1 - F is dominatedly varying, then for any r > max{μ, 0}, there exist C(r) > 0 and D(r) &g...Let F be a distribution function supported on (-∞,∞) with a finite mean μ. In this note we show that if its tail F = 1 - F is dominatedly varying, then for any r > max{μ, 0}, there exist C(r) > 0 and D(r) > 0 such thatfor all n ≥ 1 and all x≥rn. This inequality sharpens a classical inequality for the subexponential distribution case.展开更多
For the widely orthant dependent （WOD） structure, this paper mainly investigates the precise large deviations for the partial sums of WOD and non-identically distributed random variables with dominatedly varying tai...For the widely orthant dependent （WOD） structure, this paper mainly investigates the precise large deviations for the partial sums of WOD and non-identically distributed random variables with dominatedly varying tails. The obtained results extend some corresponding results.展开更多
Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 ...Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 and CCR4- associated factor 1 （CAF1）, two components of the well-characterised protein complex named CCR4-NOT. We report here that AtCAF1a and AtCAF1b, putative Arabidopsis homologs of the yeast CAF1 gene, partially complement the growth defect of the yeast call mutant in the presence of caffeine or at high temperatures. The expression of At-CAF1a and AtCAFlb is induced by multiple stress-related hormones and stimuli. Both AtCAF1a and AtCAFlb show deadenylation activity in vitro and point mutations in the predicted active sites disrupt this activity. T-DNA insertion mutants disrupting the expression of AtCAF1a and/or AtCAF1b are defective in deadenylation of stress-related mRNAs, indicating that the two AtCAF1 proteins are involved in regulated mRNA deadenylation in vivo. Interestingly, the single and double mutants of AtCAF1a and AtCAFlb show reduced expression of pathogenesis-related （PR） genes PR1 and PR2 and are more susceptible to Pseudomonas syringae pv tomato DC3000 （Pst DC3000） infection, whereas transgenic plants over-expressing AtCAFla show elevated expression of PR1 and PR2 and increased resis-tance to the same pathogen. Our results suggest roles of the AtCAF1 proteins in regulated mRNA deadenylation and defence responses to pathogen infections.展开更多
For two independent non-negative random variables X and Y, we treat X as the initial variable of major importance and Y as a modifier (such as the interest rate of a portfolio).Stability in the tail behaviors of the p...For two independent non-negative random variables X and Y, we treat X as the initial variable of major importance and Y as a modifier (such as the interest rate of a portfolio).Stability in the tail behaviors of the product compared with that of the original variable X is of practical interests. In this paper, we study the tail behaviors of the product XY when the distribution of X belongs to the classes L and S, respectively. Under appropriate conditions, we show that the distribution of the product XY is in the same class as X when X belongs to class L or S, in other words, classes L and S are stable under some mild conditions on the distribution of Y. We also show that if the distribution of X is in class L(γ) (γ＞ 0) and continuous, then the product XY is in L if and only if Y is unbounded.展开更多
This note complements a recent study in ruin theory with risky investment byestablishing the same asymptotic estimate for the finite time ruin probability under a weakerrestriction on the financial risks. In particula...This note complements a recent study in ruin theory with risky investment byestablishing the same asymptotic estimate for the finite time ruin probability under a weakerrestriction on the financial risks. In particular, our result applies to a critical case that theinsurance and financial risks have Pareto-type tails with the same regular index.展开更多
The paper proposes a statistic to test stationarity of series with κ-stable innovations and structural breaks,obtains the asymptotical distribution of the statistic,and proves the consistency of the test.To obtain cr...The paper proposes a statistic to test stationarity of series with κ-stable innovations and structural breaks,obtains the asymptotical distribution of the statistic,and proves the consistency of the test.To obtain critic values for the test without the estimation of the index κ,the paper proposes the bootstrap procedures to approximate the distribution,and proves the consistency of the procedures.The simulations demonstrate that the bootstrap test is practical and powerful.展开更多
Consumers with a penchant for healthy products brew up new trends.Tea in China is a symbol of hospitality,elegance and craftsmanship that has been honed over centuries.Born into a family of tea enthusiasts,Zhang Chi w...Consumers with a penchant for healthy products brew up new trends.Tea in China is a symbol of hospitality,elegance and craftsmanship that has been honed over centuries.Born into a family of tea enthusiasts,Zhang Chi was introduced to the beverage and all that it entails in China at a very young age.展开更多
The three-dimensional(3D)cell culture system has garnered significant attention in recent years as a means of studying cell behavior and tissue development,as opposed to traditional two-dimensional cultures.These syst...The three-dimensional(3D)cell culture system has garnered significant attention in recent years as a means of studying cell behavior and tissue development,as opposed to traditional two-dimensional cultures.These systems can induce specific cell reactions,promote specific tissue functions,and serve as valuable tools for research in tissue engineering,regenerative medicine,and drug discovery.This paper discusses current developments in the field of three-dimensional cell culture and the potential applications of 3D type 1 collagen gels to enhance the growth and maturation of dendritic cells.展开更多
Physiological and metabolic processes of ectotherms are markedly influenced by ambient temperature. Previous studies have shown that the abdominal black-speckled area becomes larger with increased elevation in plateau...Physiological and metabolic processes of ectotherms are markedly influenced by ambient temperature. Previous studies have shown that the abdominal black-speckled area becomes larger with increased elevation in plateau Phrynocephalus, however, no studies have verified the hypothesis that this variation is correlated with the lizard＇s thermoregulation. In this study, infrared thermal imaging technology was first used to study the skin temperature variation of torsos, heads, limbs and tails of a cold-climate agamid lizard, Phrynocephalus guinanensis. The heating rates of the central abdominal black-speckled skin area and peripheral non-black-speckled skin area under solar radiation were compared. Our results showed that the heating rates of limbs and tails were relatively faster than the torsos, as heating time was extended, rates gradually slowed before stabilizing under solar radiation. Under the environment without solar radiation, the cooling rates of limbs and tails were also relatively faster than the torsos of lizards, the rates slowed down and finally became stable as the cooling time was extended. We also found that the heating rate of the abdominal black-speckled skin area was faster than the nearby non-black-speckled skin area. These results increased our insights into the functional significance of these phenotypic traits and help explain their covariation with the thermal environment in these cold-climate agamid lizards.展开更多
Dear Editor,Poly(A)tails are added to the 3’-end of most mRNAs(Colgan and Manley,1997;Yu and Kim,2020).The regulatory roles of poly(A)tails have long been underestimated due to technical difficulties in analyzing hom...Dear Editor,Poly(A)tails are added to the 3’-end of most mRNAs(Colgan and Manley,1997;Yu and Kim,2020).The regulatory roles of poly(A)tails have long been underestimated due to technical difficulties in analyzing homopolymers(Chang et al.,2014;Subtelny et al.,2014).Several methods were recently developed to accurately measure their length(Chang et al.,2014;Legnini et al.,2019;Liu et al.,2019;Liu et al.展开更多
This paper presents an extension of the factor analysis model based on the normal mean-variance mixture of the Birnbaum-Saunders in the presence of nonresponses and missing data.This model can be used as a powerful to...This paper presents an extension of the factor analysis model based on the normal mean-variance mixture of the Birnbaum-Saunders in the presence of nonresponses and missing data.This model can be used as a powerful tool to model non-normal features observed from data such as strongly skewed and heavy-tailed noises.Missing data may occur due to operator error or incomplete data capturing therefore cannot be ignored in factor analysis modeling.We implement an EM-type algorithm for maximum likelihood estimation and propose single imputation of possible missing values under a missing at random mechanism.The potential and applicability of our proposed method are illustrated through analyzing both simulated and real datasets.展开更多
This paper shows the structure of the random variables with dominatedly varying tails and that of the associated random variables, and obtains some results on these r.v.s' precise moderate deviations with random c...This paper shows the structure of the random variables with dominatedly varying tails and that of the associated random variables, and obtains some results on these r.v.s' precise moderate deviations with random centralizing constants, which extend the boundary γλ(t)of large deviations to γ(λ(t)^1/s,whereγ>0,1<s<2,λ(t)is the expectation of the random index N(t),t>0.展开更多
[Methodics]As conceived by Halliday,McIntosh and Strevens(1964:201),this is'a framework of organization for language teaching which relates linguistic theory to pedagogical principles and techniques'.It entail...[Methodics]As conceived by Halliday,McIntosh and Strevens(1964:201),this is'a framework of organization for language teaching which relates linguistic theory to pedagogical principles and techniques'.It entails for each teaching situation decisions regarding limitation(restriction,selection),grading(staging,sequencing),prese ntation(initial and repeated teaching,reinforcement,remedial teaching)and testing.See also GRADING 1 SEQUENCING and STAGING.展开更多
Based on the brief overview presented above,a more direct,systematic approach toteaching communicative language abilities appears to be emerging gradually along the lines of Richards'(1990)direct approach.Such an ...Based on the brief overview presented above,a more direct,systematic approach toteaching communicative language abilities appears to be emerging gradually along the lines of Richards'(1990)direct approach.Such an approach requires,first,a detailed description of what communicative competence entails so that the subcomponents can be used as some kind of content base in syllabus design.Then the classroom activities canbe developed for each of the selected language areas.Thisdoes not necessarily implya return to traditional,structural syllabi.Pedagogic tasks combined with a systematic focus on form,as outlined by Long and Crookes(1992),could well function as the primary organizational units in a direct communicative syllabus.展开更多
基金Yan's work was supported by the Ministry of Science and Technology of China (973 Project on Mathematics) the Knowledge Innovation Program of the Chinese Academy of Sciences.
文摘Let F be a distribution function supported on (-∞,∞) with a finite mean μ. In this note we show that if its tail F = 1 - F is dominatedly varying, then for any r > max{μ, 0}, there exist C(r) > 0 and D(r) > 0 such thatfor all n ≥ 1 and all x≥rn. This inequality sharpens a classical inequality for the subexponential distribution case.
文摘For the widely orthant dependent （WOD） structure, this paper mainly investigates the precise large deviations for the partial sums of WOD and non-identically distributed random variables with dominatedly varying tails. The obtained results extend some corresponding results.
文摘Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 and CCR4- associated factor 1 （CAF1）, two components of the well-characterised protein complex named CCR4-NOT. We report here that AtCAF1a and AtCAF1b, putative Arabidopsis homologs of the yeast CAF1 gene, partially complement the growth defect of the yeast call mutant in the presence of caffeine or at high temperatures. The expression of At-CAF1a and AtCAFlb is induced by multiple stress-related hormones and stimuli. Both AtCAF1a and AtCAFlb show deadenylation activity in vitro and point mutations in the predicted active sites disrupt this activity. T-DNA insertion mutants disrupting the expression of AtCAF1a and/or AtCAF1b are defective in deadenylation of stress-related mRNAs, indicating that the two AtCAF1 proteins are involved in regulated mRNA deadenylation in vivo. Interestingly, the single and double mutants of AtCAF1a and AtCAFlb show reduced expression of pathogenesis-related （PR） genes PR1 and PR2 and are more susceptible to Pseudomonas syringae pv tomato DC3000 （Pst DC3000） infection, whereas transgenic plants over-expressing AtCAFla show elevated expression of PR1 and PR2 and increased resis-tance to the same pathogen. Our results suggest roles of the AtCAF1 proteins in regulated mRNA deadenylation and defence responses to pathogen infections.
基金supported by National Natural Science Foundation of China(Grant No.10371117)the Doctoral Program Foundation of Ministry of Education and the Special Foundation of USTC.
文摘For two independent non-negative random variables X and Y, we treat X as the initial variable of major importance and Y as a modifier (such as the interest rate of a portfolio).Stability in the tail behaviors of the product compared with that of the original variable X is of practical interests. In this paper, we study the tail behaviors of the product XY when the distribution of X belongs to the classes L and S, respectively. Under appropriate conditions, we show that the distribution of the product XY is in the same class as X when X belongs to class L or S, in other words, classes L and S are stable under some mild conditions on the distribution of Y. We also show that if the distribution of X is in class L(γ) (γ＞ 0) and continuous, then the product XY is in L if and only if Y is unbounded.
文摘This note complements a recent study in ruin theory with risky investment byestablishing the same asymptotic estimate for the finite time ruin probability under a weakerrestriction on the financial risks. In particular, our result applies to a critical case that theinsurance and financial risks have Pareto-type tails with the same regular index.
基金Supported by the National Natural Science Foundation of China (Grant Nos.1092619760972150)
文摘The paper proposes a statistic to test stationarity of series with κ-stable innovations and structural breaks,obtains the asymptotical distribution of the statistic,and proves the consistency of the test.To obtain critic values for the test without the estimation of the index κ,the paper proposes the bootstrap procedures to approximate the distribution,and proves the consistency of the procedures.The simulations demonstrate that the bootstrap test is practical and powerful.
文摘Consumers with a penchant for healthy products brew up new trends.Tea in China is a symbol of hospitality,elegance and craftsmanship that has been honed over centuries.Born into a family of tea enthusiasts,Zhang Chi was introduced to the beverage and all that it entails in China at a very young age.
文摘The three-dimensional(3D)cell culture system has garnered significant attention in recent years as a means of studying cell behavior and tissue development,as opposed to traditional two-dimensional cultures.These systems can induce specific cell reactions,promote specific tissue functions,and serve as valuable tools for research in tissue engineering,regenerative medicine,and drug discovery.This paper discusses current developments in the field of three-dimensional cell culture and the potential applications of 3D type 1 collagen gels to enhance the growth and maturation of dendritic cells.
基金supported by the National Natural Science Foundation of China (31372183, 41541002)
文摘Physiological and metabolic processes of ectotherms are markedly influenced by ambient temperature. Previous studies have shown that the abdominal black-speckled area becomes larger with increased elevation in plateau Phrynocephalus, however, no studies have verified the hypothesis that this variation is correlated with the lizard＇s thermoregulation. In this study, infrared thermal imaging technology was first used to study the skin temperature variation of torsos, heads, limbs and tails of a cold-climate agamid lizard, Phrynocephalus guinanensis. The heating rates of the central abdominal black-speckled skin area and peripheral non-black-speckled skin area under solar radiation were compared. Our results showed that the heating rates of limbs and tails were relatively faster than the torsos, as heating time was extended, rates gradually slowed before stabilizing under solar radiation. Under the environment without solar radiation, the cooling rates of limbs and tails were also relatively faster than the torsos of lizards, the rates slowed down and finally became stable as the cooling time was extended. We also found that the heating rate of the abdominal black-speckled skin area was faster than the nearby non-black-speckled skin area. These results increased our insights into the functional significance of these phenotypic traits and help explain their covariation with the thermal environment in these cold-climate agamid lizards.
基金supported by the National Key Research and Development Program of China(2018YFA0107001,2020YFA0804000)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA24020203)+4 种基金the CAS Project for Young Scientists in Basic Research(YSBR-012)the National Natural Science Foundation of China(31970588,32170606)the Natural Science Foundation of Heilongjiang province(YQ2020C003)the China Postdoctoral Science Foundation(2020M670516,2020T130687)the State Key Laboratory of Molecular Developmental Biology。
文摘Dear Editor,Poly(A)tails are added to the 3’-end of most mRNAs(Colgan and Manley,1997;Yu and Kim,2020).The regulatory roles of poly(A)tails have long been underestimated due to technical difficulties in analyzing homopolymers(Chang et al.,2014;Subtelny et al.,2014).Several methods were recently developed to accurately measure their length(Chang et al.,2014;Legnini et al.,2019;Liu et al.,2019;Liu et al.
基金This work was based on research supported by the National Research Foundation,South Africa(SRUG190308422768 Grant No.120839 and IFR170227223754 Grant No.109214)the South African NRF SARChI Research Chair in Computational and Methodological Statistics(UID:71199)The research of the corresponding author is supported by a grant from Ferdowsi University of Mashhad(N.2/54034).
文摘This paper presents an extension of the factor analysis model based on the normal mean-variance mixture of the Birnbaum-Saunders in the presence of nonresponses and missing data.This model can be used as a powerful tool to model non-normal features observed from data such as strongly skewed and heavy-tailed noises.Missing data may occur due to operator error or incomplete data capturing therefore cannot be ignored in factor analysis modeling.We implement an EM-type algorithm for maximum likelihood estimation and propose single imputation of possible missing values under a missing at random mechanism.The potential and applicability of our proposed method are illustrated through analyzing both simulated and real datasets.
基金This research is supported by National Science Foundation of China (No. 10271087).
文摘This paper shows the structure of the random variables with dominatedly varying tails and that of the associated random variables, and obtains some results on these r.v.s' precise moderate deviations with random centralizing constants, which extend the boundary γλ(t)of large deviations to γ(λ(t)^1/s,whereγ>0,1<s<2,λ(t)is the expectation of the random index N(t),t>0.
文摘[Methodics]As conceived by Halliday,McIntosh and Strevens(1964:201),this is'a framework of organization for language teaching which relates linguistic theory to pedagogical principles and techniques'.It entails for each teaching situation decisions regarding limitation(restriction,selection),grading(staging,sequencing),prese ntation(initial and repeated teaching,reinforcement,remedial teaching)and testing.See also GRADING 1 SEQUENCING and STAGING.
文摘Based on the brief overview presented above,a more direct,systematic approach toteaching communicative language abilities appears to be emerging gradually along the lines of Richards'(1990)direct approach.Such an approach requires,first,a detailed description of what communicative competence entails so that the subcomponents can be used as some kind of content base in syllabus design.Then the classroom activities canbe developed for each of the selected language areas.Thisdoes not necessarily implya return to traditional,structural syllabi.Pedagogic tasks combined with a systematic focus on form,as outlined by Long and Crookes(1992),could well function as the primary organizational units in a direct communicative syllabus.
