Burkina Faso is a Sahelian country in West Africa that is faced with water re-source mobilization problems.To develop vital sectors of its economy such as agriculture and livestock breeding,the country has elected to ...Burkina Faso is a Sahelian country in West Africa that is faced with water re-source mobilization problems.To develop vital sectors of its economy such as agriculture and livestock breeding,the country has elected to mobilize surface water through the construction of small earthen dams.With a stock of almost a thousand dams,the country is now faced with the problem of ageing struc-tures,with embankments sometimes breaking during periods of high flood-ing.To deal with this situation,Burkina Faso has taken action to rehabilitate its dams.The planned maintenance work will,however,require prior diag-nostics,which,given the number of structures to be examined,will constitute a real challenge.On this subject,geophysics offers detection methods that can be applied to the diagnosis of internal erosion problems that frequently affect earthen dams.In this regard,the study of the small Gonsédam illustrates the contribution of geophysical methods to the detection of areas of water leaks through an earthen embankment.It demonstrates that,with the use of elec-tromagnetic and electrical methods,it is possible to establish an initial diag-nosis of structures through a routine of simple,rapid and non-invasive meas-urements.展开更多
In this paper, we give a new characterization of Mobius transformations. To do this, we extend the notion of Apollonius points of a triangle and of a pentagon, to the notion of Apollonius points of an arbitrary （2n-1...In this paper, we give a new characterization of Mobius transformations. To do this, we extend the notion of Apollonius points of a triangle and of a pentagon, to the notion of Apollonius points of an arbitrary （2n-1）-gon.展开更多
Kinase,putative Endopeptidase,and Other Proteins of Small size(KEOPS)is a multisubunit protein complex conserved in eukaryotes and archaea.It is composed of Pcc1,Kae1,Bud32,Cgi121,and Gon7 in eukaryotes and is primari...Kinase,putative Endopeptidase,and Other Proteins of Small size(KEOPS)is a multisubunit protein complex conserved in eukaryotes and archaea.It is composed of Pcc1,Kae1,Bud32,Cgi121,and Gon7 in eukaryotes and is primarily involved in N^(6)-threonylcarbamoyl adenosine(t^(6)A)modification of transfer RNAs(tRNAs).Recently,it was reported that KEOPS participates in homologous recombination(HR)repair in yeast.To characterize the KEOPS in archaea(aKEOPS),we conducted genetic and biochemical analyses of its encoding genes in the hyperthermophilic archaeon Saccharolobus islandicus.We show that aKEOPS also possesses five subunits,Pcc1,Kae1,Bud32,Cgi121,and Pcc1-like(or Gon7-like),just like eukaryotic KEOPS.Pcc1-like has physical interactions with Kae1 and Pcc1 and can mediate the monomerization of the dimeric subcomplex(Kae1-Pcc1-Pcc1-Kae1),suggesting that Pcc1-like is a functional homolog of the eukaryotic Gon7 subunit.Strikingly,none of the genes encoding aKEOPS subunits,including Pcc1 and Pcc1-like,can be deleted in the wild type and in a t^(6)A modification complementary strain named TsaKI,implying that the aKEOPS complex is essential for an additional cellular process in this archaeon.Knock-down of the Cgi121 subunit leads to severe growth retardance in the wild type that is partially rescued in TsaKI.These results suggest that aKEOPS plays an essential role independent of the cellular t^(6)A modification level.In addition,archaeal Cgi121 possesses dsDNA-binding activity that relies on its tRNA 3ʹCCA tail binding module.Our study clarifies the subunit organization of archaeal KEOPS and suggests an origin of eukaryotic Gon7.The study also reveals a possible link between the function in t^(6)A modification and the additional function,presumably HR.展开更多
In this article we continue the consideration of geometrical constructions of regular n-gons for odd n by rhombic bicompasses and ruler used in [1] for the construction of the regular heptagon (n=7). We discuss the po...In this article we continue the consideration of geometrical constructions of regular n-gons for odd n by rhombic bicompasses and ruler used in [1] for the construction of the regular heptagon (n=7). We discuss the possible factorization of the cyclotomic polynomial in polynomial factors which contain not higher than quadratic radicals in the coefficients whereas usually the factorization of the cyclotomic polynomials is considered in products of irreducible factors with integer coefficients. In considering the regular heptagon we find a modified variant of its construction by rhombic bicompasses and ruler. In detail, supported by figures, we investigate the case of the regular tridecagon (n=13) which in addition to n=7 is the only candidate with low n (the next to this is n=769 ) for which such a construction by rhombic bicompasses and ruler seems to be possible. Besides the coordinate origin we find here two points to fix for the possible application of two bicompasses (or even four with the addition of the complex conjugate points to be fixed). With only one bicompass one has in addition the problem of the trisection of an angle which can be solved by a neusis construction that, however, is not in the spirit of constructions by compass and ruler and is difficult to realize during the action of bicompasses. As discussed it seems that to finish the construction by bicompasses the correlated action of two rhombic bicompasses must be applied in this case which avoids the disadvantages of the neusis construction. Single rhombic bicompasses allow to draw at once two circles around two fixed points in such correlated way that the position of one of the rotating points on one circle determines the positions of all the other points on the second circle in unique way. The known case n=17 embedded in our method is discussed in detail.展开更多
Trang Bang is the largest agricultural production district of TayNinh province, Vietnam that has a great influence on the socio-economic development of the whole province. This study assessed land use - land cover cha...Trang Bang is the largest agricultural production district of TayNinh province, Vietnam that has a great influence on the socio-economic development of the whole province. This study assessed land use - land cover change in Trang Bang district from 1995 to 2017, the results provide scientific evidence for the safe and effective identification of causes and safeguards for mulch. The study was conducted by an expert classification system and the land use/land cover (LULC) was classified into 6 classes: food-crops, fruit-tree, water, built-up, industry and shrub. The result showed that the LULC there decreased between 1995 and 2017. All the two land cover types (food-crops, fruit-tree) decreased 141.2 km2 (41.4%) in 2017 compared with 1995, while the area of industrial and urban land (industry, built-up) increased 70.0 km2 (20.6%). The overall classification accuracies in 1995, 2007, and 2017 were 94.2%, 98.0%, and 96.3% respectively. The overall kappa coefficients for the image classification were 0.90, 0.97, and 0.94 in 1995, 2007, and 2017 respectively. In general, the average classification was above 90%, and this proved that the classification was reliable and acceptable. The result show that the LULC in the study area decreased during 1997-2017 and tended to decrease in recent years.展开更多
文摘Burkina Faso is a Sahelian country in West Africa that is faced with water re-source mobilization problems.To develop vital sectors of its economy such as agriculture and livestock breeding,the country has elected to mobilize surface water through the construction of small earthen dams.With a stock of almost a thousand dams,the country is now faced with the problem of ageing struc-tures,with embankments sometimes breaking during periods of high flood-ing.To deal with this situation,Burkina Faso has taken action to rehabilitate its dams.The planned maintenance work will,however,require prior diag-nostics,which,given the number of structures to be examined,will constitute a real challenge.On this subject,geophysics offers detection methods that can be applied to the diagnosis of internal erosion problems that frequently affect earthen dams.In this regard,the study of the small Gonsédam illustrates the contribution of geophysical methods to the detection of areas of water leaks through an earthen embankment.It demonstrates that,with the use of elec-tromagnetic and electrical methods,it is possible to establish an initial diag-nosis of structures through a routine of simple,rapid and non-invasive meas-urements.
文摘In this paper, we give a new characterization of Mobius transformations. To do this, we extend the notion of Apollonius points of a triangle and of a pentagon, to the notion of Apollonius points of an arbitrary （2n-1）-gon.
基金supported by the National Key Research and Development Program of China(No.2020YFA0906800)the National Natural Science Foundation of China(Nos.31970546 and 31670061 to Y.S.,31900055 to Q.H.,31970119 to J.N.,and 31771380 to Q.S.)the State Key Laboratory of Microbial Technology.
文摘Kinase,putative Endopeptidase,and Other Proteins of Small size(KEOPS)is a multisubunit protein complex conserved in eukaryotes and archaea.It is composed of Pcc1,Kae1,Bud32,Cgi121,and Gon7 in eukaryotes and is primarily involved in N^(6)-threonylcarbamoyl adenosine(t^(6)A)modification of transfer RNAs(tRNAs).Recently,it was reported that KEOPS participates in homologous recombination(HR)repair in yeast.To characterize the KEOPS in archaea(aKEOPS),we conducted genetic and biochemical analyses of its encoding genes in the hyperthermophilic archaeon Saccharolobus islandicus.We show that aKEOPS also possesses five subunits,Pcc1,Kae1,Bud32,Cgi121,and Pcc1-like(or Gon7-like),just like eukaryotic KEOPS.Pcc1-like has physical interactions with Kae1 and Pcc1 and can mediate the monomerization of the dimeric subcomplex(Kae1-Pcc1-Pcc1-Kae1),suggesting that Pcc1-like is a functional homolog of the eukaryotic Gon7 subunit.Strikingly,none of the genes encoding aKEOPS subunits,including Pcc1 and Pcc1-like,can be deleted in the wild type and in a t^(6)A modification complementary strain named TsaKI,implying that the aKEOPS complex is essential for an additional cellular process in this archaeon.Knock-down of the Cgi121 subunit leads to severe growth retardance in the wild type that is partially rescued in TsaKI.These results suggest that aKEOPS plays an essential role independent of the cellular t^(6)A modification level.In addition,archaeal Cgi121 possesses dsDNA-binding activity that relies on its tRNA 3ʹCCA tail binding module.Our study clarifies the subunit organization of archaeal KEOPS and suggests an origin of eukaryotic Gon7.The study also reveals a possible link between the function in t^(6)A modification and the additional function,presumably HR.
文摘In this article we continue the consideration of geometrical constructions of regular n-gons for odd n by rhombic bicompasses and ruler used in [1] for the construction of the regular heptagon (n=7). We discuss the possible factorization of the cyclotomic polynomial in polynomial factors which contain not higher than quadratic radicals in the coefficients whereas usually the factorization of the cyclotomic polynomials is considered in products of irreducible factors with integer coefficients. In considering the regular heptagon we find a modified variant of its construction by rhombic bicompasses and ruler. In detail, supported by figures, we investigate the case of the regular tridecagon (n=13) which in addition to n=7 is the only candidate with low n (the next to this is n=769 ) for which such a construction by rhombic bicompasses and ruler seems to be possible. Besides the coordinate origin we find here two points to fix for the possible application of two bicompasses (or even four with the addition of the complex conjugate points to be fixed). With only one bicompass one has in addition the problem of the trisection of an angle which can be solved by a neusis construction that, however, is not in the spirit of constructions by compass and ruler and is difficult to realize during the action of bicompasses. As discussed it seems that to finish the construction by bicompasses the correlated action of two rhombic bicompasses must be applied in this case which avoids the disadvantages of the neusis construction. Single rhombic bicompasses allow to draw at once two circles around two fixed points in such correlated way that the position of one of the rotating points on one circle determines the positions of all the other points on the second circle in unique way. The known case n=17 embedded in our method is discussed in detail.
文摘Trang Bang is the largest agricultural production district of TayNinh province, Vietnam that has a great influence on the socio-economic development of the whole province. This study assessed land use - land cover change in Trang Bang district from 1995 to 2017, the results provide scientific evidence for the safe and effective identification of causes and safeguards for mulch. The study was conducted by an expert classification system and the land use/land cover (LULC) was classified into 6 classes: food-crops, fruit-tree, water, built-up, industry and shrub. The result showed that the LULC there decreased between 1995 and 2017. All the two land cover types (food-crops, fruit-tree) decreased 141.2 km2 (41.4%) in 2017 compared with 1995, while the area of industrial and urban land (industry, built-up) increased 70.0 km2 (20.6%). The overall classification accuracies in 1995, 2007, and 2017 were 94.2%, 98.0%, and 96.3% respectively. The overall kappa coefficients for the image classification were 0.90, 0.97, and 0.94 in 1995, 2007, and 2017 respectively. In general, the average classification was above 90%, and this proved that the classification was reliable and acceptable. The result show that the LULC in the study area decreased during 1997-2017 and tended to decrease in recent years.
