This paper proposes a new version of the high-resolution entropy-consistent(EC-Limited)flux for hyperbolic conservation laws based on a new minmod-type slope limiter.Firstly,we identify the numerical entropy productio...This paper proposes a new version of the high-resolution entropy-consistent(EC-Limited)flux for hyperbolic conservation laws based on a new minmod-type slope limiter.Firstly,we identify the numerical entropy production,a third-order differential term deduced from the previous work of Ismail and Roe[11].The corresponding dissipation term is added to the original Roe flux to achieve entropy consistency.The new,resultant entropy-consistent(EC)flux has a general and explicit analytical form without any corrective factor,making it easy to compute and a less-expensive method.The inequality constraints are imposed on the standard piece-wise quadratic reconstruction to enforce the pointwise values of bounded-type numerical solutions.We design the new minmod slope limiter as combining two separate limiters for left and right states.We propose the EC-Limited flux by adding this reconstruction data method to the primitive variables rather than to the conservative variables of the EC flux to preserve the equilibrium of the primitive variables.These resulting fluxes are easily applied to general hyperbolic conservation laws while having attractive features:entropy-stable,robust,and non-oscillatory.To illustrate the potential of these proposed fluxes,we show the applications to the Burgers equation and the Euler equations.展开更多
[Objectives]To explore the effects of spatial density of farmland shelterbelts on NDVI on the northern slope of Tianshan Mountains.[Methods]Taking the economic belt of the northern slope of the Tianshan Mountains as t...[Objectives]To explore the effects of spatial density of farmland shelterbelts on NDVI on the northern slope of Tianshan Mountains.[Methods]Taking the economic belt of the northern slope of the Tianshan Mountains as the research area and using the grid method,the spatial density distribution of farmland shelterbelts can be known.Combining the grid method with NDVI data,the average value of normalized difference vegetation index(NDVI)during the growing period of crops can be obtained.In addition,the protection benefits of the shelterbelts on crops were analyzed through comparing the growth of crops within the protection zone with and without protection.[Results]The grids with shelterbelt distribution were better than the grids without shelterbelt distribution,and the shelterbelt played a great role in promoting crop growth.In the middle stage of crop growth,the protection benefit of shelterbelt was significant.The spatial density of shelterbelts was unevenly distributed in the range of 0.6 to 0.8,and the protection benefits were poor.[Conclusions]It is expected to explore the effects of shelterbelts on crop growth at a larger regional scale,so as to provide a basis for the management and design of shelterbelts in the future,and to provide a theoretical basis for studying the protective effect of farmland shelterbelts on crops.展开更多
Spinosyns,including spinosad and spinetoram,act on the insect central nervous system,gradually paralyzing or destroying the target insect.Spinosad resistance is associated with loss-of-function mutations in the nicoti...Spinosyns,including spinosad and spinetoram,act on the insect central nervous system,gradually paralyzing or destroying the target insect.Spinosad resistance is associated with loss-of-function mutations in the nicotinic acetylcholine receptor(nAChR)α6 subunit in a number of agricultural pests.Using gene editing,nAChRα6 has been verified as a target for spinosyns in five insect species.Recently,a point mutation(G275E)in exon 9 of nAChRα6 was identified in spinosad-resistant strains of Thrips palmi and Tuta absoluta.To date,no in vivo functional evidence has been obtained to support that this mutation is involved in spinosyn resistance in lepidopteran pests.In this study,the G275E mutation was introduced into the nAChR of Spodoptera exigua using clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)gene-editing technology.Reverse transcriptase-polymerase chain reaction and sequencing confirmed that this mutation was present in exon 9 of the nAChR transcripts in the edited 275E strain.The results of bioassays showed that the 275E strain was highly resistant to spinosad(230-fold)and spinetoram(792-fold)compared to the unedited background strain,directly confirming that the G275E mutation of the nAChRα6 subunit confers high levels of spinosyn resistance in S.exigua.Inheritance analysis showed that the resistance trait is autosomal and incompletely recessive.This study employs a reverse genetics approach to validate the functional role played by the G275E mutation in nAChRα6 of S.exigua in spinosyns resistance and provides another example of the use of CRISPR/Cas9 gene-editing technology to confirm the role played by candidate target site mutations in insecticide resistance.展开更多
基金the National Natural Science Found Project of China through project number 11971075.
文摘This paper proposes a new version of the high-resolution entropy-consistent(EC-Limited)flux for hyperbolic conservation laws based on a new minmod-type slope limiter.Firstly,we identify the numerical entropy production,a third-order differential term deduced from the previous work of Ismail and Roe[11].The corresponding dissipation term is added to the original Roe flux to achieve entropy consistency.The new,resultant entropy-consistent(EC)flux has a general and explicit analytical form without any corrective factor,making it easy to compute and a less-expensive method.The inequality constraints are imposed on the standard piece-wise quadratic reconstruction to enforce the pointwise values of bounded-type numerical solutions.We design the new minmod slope limiter as combining two separate limiters for left and right states.We propose the EC-Limited flux by adding this reconstruction data method to the primitive variables rather than to the conservative variables of the EC flux to preserve the equilibrium of the primitive variables.These resulting fluxes are easily applied to general hyperbolic conservation laws while having attractive features:entropy-stable,robust,and non-oscillatory.To illustrate the potential of these proposed fluxes,we show the applications to the Burgers equation and the Euler equations.
基金Basic Scientific Research Project of Non-profit Scientific Research Institutes in Xinjiang Uygur Autonomous Region(KY2022137).
文摘[Objectives]To explore the effects of spatial density of farmland shelterbelts on NDVI on the northern slope of Tianshan Mountains.[Methods]Taking the economic belt of the northern slope of the Tianshan Mountains as the research area and using the grid method,the spatial density distribution of farmland shelterbelts can be known.Combining the grid method with NDVI data,the average value of normalized difference vegetation index(NDVI)during the growing period of crops can be obtained.In addition,the protection benefits of the shelterbelts on crops were analyzed through comparing the growth of crops within the protection zone with and without protection.[Results]The grids with shelterbelt distribution were better than the grids without shelterbelt distribution,and the shelterbelt played a great role in promoting crop growth.In the middle stage of crop growth,the protection benefit of shelterbelt was significant.The spatial density of shelterbelts was unevenly distributed in the range of 0.6 to 0.8,and the protection benefits were poor.[Conclusions]It is expected to explore the effects of shelterbelts on crop growth at a larger regional scale,so as to provide a basis for the management and design of shelterbelts in the future,and to provide a theoretical basis for studying the protective effect of farmland shelterbelts on crops.
基金funded by the National Natural Science Foundation of China(32001941 and 31972303)the China Postdoctoral Science Foundation(2020M683586)the Research Fund for the Doctoral Program of Northwest A&F University(Z1090219195).
文摘Spinosyns,including spinosad and spinetoram,act on the insect central nervous system,gradually paralyzing or destroying the target insect.Spinosad resistance is associated with loss-of-function mutations in the nicotinic acetylcholine receptor(nAChR)α6 subunit in a number of agricultural pests.Using gene editing,nAChRα6 has been verified as a target for spinosyns in five insect species.Recently,a point mutation(G275E)in exon 9 of nAChRα6 was identified in spinosad-resistant strains of Thrips palmi and Tuta absoluta.To date,no in vivo functional evidence has been obtained to support that this mutation is involved in spinosyn resistance in lepidopteran pests.In this study,the G275E mutation was introduced into the nAChR of Spodoptera exigua using clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)gene-editing technology.Reverse transcriptase-polymerase chain reaction and sequencing confirmed that this mutation was present in exon 9 of the nAChR transcripts in the edited 275E strain.The results of bioassays showed that the 275E strain was highly resistant to spinosad(230-fold)and spinetoram(792-fold)compared to the unedited background strain,directly confirming that the G275E mutation of the nAChRα6 subunit confers high levels of spinosyn resistance in S.exigua.Inheritance analysis showed that the resistance trait is autosomal and incompletely recessive.This study employs a reverse genetics approach to validate the functional role played by the G275E mutation in nAChRα6 of S.exigua in spinosyns resistance and provides another example of the use of CRISPR/Cas9 gene-editing technology to confirm the role played by candidate target site mutations in insecticide resistance.
