To characterize m-weak group inverses,several algebraic methods are used,such as the use of idempotents,one-side principal ideals,and units.Consider an element a within a unitary ring that possesses Drazin invertibili...To characterize m-weak group inverses,several algebraic methods are used,such as the use of idempotents,one-side principal ideals,and units.Consider an element a within a unitary ring that possesses Drazin invertibility and an involution.This paper begins by outlining the conditions necessary for the existence of the m-weak group inverse of a.Moreover,it explores the criteria under which a can be considered pseudo core invertible and weak group invertible.In the context of a weak proper*-ring,it is proved that a is weak group invertible if,and only if,a D can serve as the weak group inverse of au,where u represents a specially invertible element closely associated with a D.The paper also introduces a counterexample to illustrate that a D cannot universally serve as the pseudo core inverse of another element.This distinction underscores the nuanced differences between pseudo core inverses and weak group inverses.Ultimately,the discussion expands to include the commuting properties of weak group inverses,extending these considerations to m-weak group inverses.Several new conditions on commuting properties of generalized inverses are given.These results show that pseudo core inverses,weak group inverses,and m-weak group inverses are not only closely linked but also have significant differences that set them apart.展开更多
To screen the high efficient mixed culture and understand the bioleaching behaviors of mixed culture for low-grade copper sulfide ore bioleaching,ten mixed cultures were collected and screened from different acid mine...To screen the high efficient mixed culture and understand the bioleaching behaviors of mixed culture for low-grade copper sulfide ore bioleaching,ten mixed cultures were collected and screened from different acid mine drainages obtained from sulfide mines of China.The leaching rate was set as criterion to screen the mixed culture and the metagenomic approach.Community genome array(CGA) was used for analyzing the mixed culture microbial community shift during the bioleaching process.The results indicate that the mixed culture obtained from Yinshan(YS) lead-zinc mine in Dexing of Jiangxi province in China reaches the maximum copper extraction(68.89%) during the one bioleaching period of 24 d.CGA results show that YS culture contains nine kinds of bacteria which are belong to six divisions,and the microbial community structure is changing during the bioleaching process.This provides a good way to accelerate the bioleaching process and reveals the microbial community shift during the bioleaching process.展开更多
How to restore the destroyed forest after forest fire is a key question that man must face. This paper reviewed the research situation and history on the forest restoration burned blanks and summed up the research met...How to restore the destroyed forest after forest fire is a key question that man must face. This paper reviewed the research situation and history on the forest restoration burned blanks and summed up the research methods used into four scales: seed-bank scale, community scale, ecosystem scale and landscape scale. The new technologies such as GIS & Remote Sensing used to vegetation restoration were also summarized. The strategies and developing trend of vegetation restoration research on burned blanks were discussed.展开更多
Amplified fragment length polymorphism(AFLP)was used to analyze 2 populations: Schima superba Gardn. et Champ. and Castanopsis chinensis Hance. across three different communities representing three succession ...Amplified fragment length polymorphism(AFLP)was used to analyze 2 populations: Schima superba Gardn. et Champ. and Castanopsis chinensis Hance. across three different communities representing three succession stages, in Dinghu Mountain, China. These two were middle succession species in the lower subtropical broad_leaved forest. Four AFLP primer combinations using total 48 individuals of S. superba provided 24, 40, 27 and 27 reliable bands, of which 15, 23, 23 and 16 were polymorphic, respectively. Similarly, total 48 individuals of C. chinensis provided 27, 20, 33 and 39 reliable bands, of which 12, 5, 15 and 13 were polymorphic respectively. These bands were used as presence/absence data to assess the levels of genetic variation and population structure of those species. From average heterozygosity, S. superba possessed higher molecular variation than C. chinensis . Analysis of molecular variance(AMOVA)indicated that most of the genetic variation of S. superba was due to the differences within population(95.99%, P <0.001), with 4.01% ( P <0.001)genetic variation among population. Similarly, AMOVA indicated the most of the genetic variation of C. chinensis was due to the differences within population(75.36%, P <0.001), with 24.64%( P <0.001)genetic variation among communities(24.64%). DCA(Detrended Correspondence Analysis) analysis showed that the individuals of S. superba from the same community did not cluster together, while the individuals of C. chinensis from the same community roughly cluster together. The above results reflected the biological characteristics of the two different species suggesting the significant effect of microenvironment of different community on population differentiation and its relationship of which to forest succession resulted in genetic divergence.展开更多
To assess the genetic diversity between randomly and selectively bred populations,we sequenced 438 bp of the mitochondrial DNA control region from 102 pigs.These samples represented four native pig breeds,one nucleus ...To assess the genetic diversity between randomly and selectively bred populations,we sequenced 438 bp of the mitochondrial DNA control region from 102 pigs.These samples represented four native pig breeds,one nucleus and one conservation herd from Yunnan,China.Twenty haplotypes with sixteen polymorphic sites were identified.The number of haplotypes in the nucleus herd of Saba pig and the conservation herd of Banna miniature pig were restricted to three and one,respectively,while the randomly bred pig populations exhibited over six haplotypes.Notably,haplotype diversity in randomly bred populations was significantly greater than the selectively bred populations(h=0.732 vs.0.425 and 0,exact test,P≤0.0036).These findings demonstrate that selective breeding generated low genetic diversity compared to randomly bred pig breeds.A timely intervention and well programmed breeding approach would stop further genetic diversity reduction in the nucleus and conservation herds of native pig breeds.Otherwise,selective breeding would dramatically reduce genetic diversity in only several years,indicating that sharp contradictions exist between breeding,conservation and genetic diversity.Genetic relationships are discussed based on net genetic distances among pig populations.展开更多
This study was designed to introduce a new method of estimating group size and composition of black-andwhite snub-nosed monkeys (Rhinopithecus bieti ) on the basis of faecal amount at sleeping sites at Mt. Baima Nat...This study was designed to introduce a new method of estimating group size and composition of black-andwhite snub-nosed monkeys (Rhinopithecus bieti ) on the basis of faecal amount at sleeping sites at Mt. Baima Nature Reserve. The monkeys spend nights in the form of one-male, multi-female units (OMUs) and all-male units (AMU), and their faecal pellets can be classified into three categories: adult males (the largest), adult females (moderate) and immatures (the smallest) based on their size. Total pellets were counted under sleeping trees used for two nights at Nanren village (99°04′E, 28°34′N, northwest of Yunnan Province, China) in each of four seasons in 2000- 2001. Moreover, data on group composition were collected when the monkeys were passing through an open gully in November 2001. Since the number of adults in OMUs shows a positive significant correlation with the amount of pellets amount in each season, the mean number of feces produced per night per individual is the slope of the regression lines. Thus, group size and composition can be relatively reliably and accurately estimated by the faeces under trees compared with the previous methods of estimation, including the use of monkeys' activities and tracks such as broken branches on steep slopes, in deep gorges and under lower visibility. The use of pellets for population estimates displayed 9.4% deviation in regards to population size of adult females. Some causes of the bias were also discussed. The method might be applicable to other monkey groups of this species if their habitats and main foods are similar to those of the study group.展开更多
Microsatellite DNA technique was used to detect the genetic variation between five hatchery populations of the Pacific oyster from China and two wild populations from Japan. Seven microsatellite loci screened in this ...Microsatellite DNA technique was used to detect the genetic variation between five hatchery populations of the Pacific oyster from China and two wild populations from Japan. Seven microsatellite loci screened in this study showed high polymorphism in both hatchery and wild populations, as observed in an average number of allele per locus (19.1-29.9) and average expected heterozygosity (0.916-0.958). No significant difference in average allelic richness or expected heterozygosity was observed between Chinese hatchery populations and Japanese wild populations. Pairwise Fsr values and heterogeneity tests of allele frequencies showed significant genetic differentiation between all populations. According to the neighbor-joining tree constructed on the basis of the Dc distance, the seven populations fell into three groups showing a clear division between hatchery and wild populations, and between the northern and southern hatchery populations. Assignment tests correctry assigned high percentages (97%-100%) of individuals to their original populations and demonstrated the feasibility of microsatellite analysis for discrimination between populations. The information obtained in this study is useful for designing suitable management guidelines and selective breeding programs for the Pacific oyster in China.展开更多
The main purpose of this study was to examine the effects of plant species diversity and functional composition (the identity of the plant functional groups) on ecosystem stability of Stipa, communities in the Inner M...The main purpose of this study was to examine the effects of plant species diversity and functional composition (the identity of the plant functional groups) on ecosystem stability of Stipa, communities in the Inner Mongolia Plateau. The research work was based on a 12-year study (from 1984 to 1995) of species abundance, diversity, and primary productivity of four Stipa communities, i.e. S. baicalensis Roshev., S. grandis P. Smirn., S, krylovii Roshev., and S. klemenzii Roshev. respectively. The Shnnon-Wiener index was used as a measurement of plant diversity, while functional composition was used to differentiate the functional groups that were included in the communities. The plant species of four Stipa communities were classified into functional groups based on the differences in life forms and ecological groups, which influence their performance in resource requirements, seasonality of growth, tolerance to water stress, and life history. Plant species were classified into five functional groups based on their differences in life form, shrubs and half shrubs, perennial bunch grasses, perennial rhizome grasses, forbs, annuals and biennials. Based on their differences in water requirement these species were classified into four functional groups: xerads, intermediate xerads, intermediate mesophytes, and mesophytes. The results showed: 1) Plant species diversity stabilized ecosystem processes. Shannon-Wiener index were 2.401 4, 2.172 0, 1.624 8, 0.354 3 from S. baicalensis community to S. grandis, S. krylovii and S. klemenzii community, respectively. The dynamics of the aboveground net primary productivity (ANPP) for a 12-year's period showed a reverse pattern, the coefficients of variation of the four communities were 21.94%, 20.63%, 29.21% and 39.72% respectively. 2) The Life form functional group component of diversity was a greater determinant of the ecosystem processes than the species component of diversity. The effects of perennial bunch grasses, perennial rhizome grasses and forbs on community stability were highly significant. 3) The ecological group component of diversity was also a great determinant of the ecosystem processes. The effects of xerads, intermediate xerads, and mesophytes on community stability were also very strong.展开更多
[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of ...[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of major and auxiliary nec-tariferous plants, six Apis mel ifera colonies were selected for measure the number of eggs, larvae, pupae and adult bees from Jan. to Dec. in 2012; based on that, their annual change curves were also plotted. [Result] The results showed that there were three peaks of the total number of A. mel ifera workers throughout the year:the first occurred on May 15th, with bees developed into an ideal population for col-lecting pomegranate nectar, and the second and third peaks occurred on July 15th and Oct. 15th, respectively, with bees developed into an ideal population for col ect-ing E. ciliate (Thuab) Hyland. [Conclusion] Prevention of Varroa jacobsoni should be carried out with two or more types of acaricides at the late nectar flow stages of the two nectariferous plants(pomegranate and E. ciliate (Thuab) Hyland) when there was a nectar deficiency. Prevention of Tropilaelaps clareae should be timely per-formed with sublimed sulfur in conjunction with acaricides. This study provides a theoretical basis for the high-quality and high-yielding production of honey, as wel as for the product safety.展开更多
A presentation of hyperbolic unitary group is an important part in the unitary group. The group KG 2,n (R) plays an elementary role in presentation of unitary group. It is proved that KG 2,n(R)=1 for n≥2 over a...A presentation of hyperbolic unitary group is an important part in the unitary group. The group KG 2,n (R) plays an elementary role in presentation of unitary group. It is proved that KG 2,n(R)=1 for n≥2 over a ring R with division ring of quotients, using a new method, and a presentation of GE n(R) is given.展开更多
The characteristics of macrofauna communities in three mangrove assemblages [Avicennia marina+Acgiceras corniculatum (MC)community, A.corniculatum (C) community and Bruguiera gymnorrhiza+A.corniculatum (GC) co...The characteristics of macrofauna communities in three mangrove assemblages [Avicennia marina+Acgiceras corniculatum (MC)community, A.corniculatum (C) community and Bruguiera gymnorrhiza+A.corniculatum (GC) community] were studied in Zhanjiang Mangrove Nature Reserves during 2005 and 2006. Of the three mangrove assemblages, the macrofauna species number, density, biomass, Richness index and Shannon-Wiener index were the highest, and the Simpson dominance index was medial at MC community. However the Pielou Evenness index of MC community was slightly lower than that at C community. At C community, the number of macrofauna species obviously reduced, especially infaunal, caving and adhering life forms, and the biomass and density were the lowest. Because of the even distribution of individuals of different species, the Simpson dominance index was the lowest and the evenness index was the highest. Although the Richness index at C community was slightly lower than that at MC community, the Shannon-Wiener index was near to that at MC community. At GC community, the number of macrofauna species, especially infaunal and caving life forms, continued to decrease comparing C community, but the biomass and density increased slightly. As the distribution of individuals of different species was uneven, the Simpson dominance index was the highest and the Pielou Evenness index was the lowest. Furthermore, the Richness index dropped to the lowest. The Shannon-Wiener index also dropped accordingly to the lowest. The dominant life forms of MC were infaunal and caving, while those of C and GC community were both caving. The ratio of the GS/GSB of macrofauna communities in the three mangrove assemblages were 0.48, 0.63 and 0.80, respectively. The community structures at the same mangrove assemblages were all quite similar, with those at GC community being most similar. However, there were obvious differences among the community structures at the three different mangrove assemblages. These results implied that the different mangrove assemblages had different affects on the macrofauna communities and shed light on the macrofauna adaptation capability to specific habitats.展开更多
The competition-density effect of plant populations is of significance in theory and practice of forest management and has been studied for long time. The differences between the two reciprocal equations of the compet...The competition-density effect of plant populations is of significance in theory and practice of forest management and has been studied for long time. The differences between the two reciprocal equations of the competition-density effect in nonself-thinning populations and self-thinning populations were analyzed theoretically. This supplies a theoretical basis for analyzing the dynamics of forest populations and evaluating the effect of forest management.展开更多
Dovetree (Davidia involucrate), one of the first-class protective plants in China, is a relic species of paleotropical kingdom in Tertiary period, belonging toDavidiaceae with a single genus. In recent years, the incr...Dovetree (Davidia involucrate), one of the first-class protective plants in China, is a relic species of paleotropical kingdom in Tertiary period, belonging toDavidiaceae with a single genus. In recent years, the increase of regional developing projects has led to a sharp decrease of this ancient and rare plant in naturally distributed habitats and natural population. In this paper, the biological and ecological characteristics of Dovetree were described, and the geographically distributed condition of this species in different geologic periods as well as the major reasons for dynamic changes of its population were systematically analyzed in accordance with field researches and references. The investigations conducted in different years by setting up standard sample plots showed that the population number of Dovetree increased yearly in the areas without human interference but decreased yearly in the areas with human interference. With the increase of population density and human activities decreased as the logarithmic curve:Y=?100.7ln(x)+178.09, and it has turned from a dominant population into an endangered population. Based on the former and present studies on Dovetree, some protection strategies were put foreword for protecting this ancient and rare species. Keywords Davidia involucrate - Dovetree - Geographical Distribution - Biological Characteristics - Protection Policy CLC number S718.4 Document code A Article ID 1007-662X(2004)01-0039-06 Foundation Item: This research was coordinated by the National Natural Science Foundation of China (No. 39970591)Biography: Wu Gang (1965-), Male, Professor in Key Laboratory of Systems Ecology, Research Center for Eco Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.Responsible editor: Chai Ruihai展开更多
[Objective] The behavior of eating, drinking, defecating and peeing of 1 500 pigs in a large-scale microbial fermentation bed-equipped piggery was observed. We hoped to find some simple indicators that could reflect t...[Objective] The behavior of eating, drinking, defecating and peeing of 1 500 pigs in a large-scale microbial fermentation bed-equipped piggery was observed. We hoped to find some simple indicators that could reflect the health status of swinery and to provide experience for the swinery performance management in large-scale microbial fermentation bed-equipped piggery. [Method] The body weight (BW), daily BW gain, feed intake and other indicators of different-day-old pigs were recorded in details. Based on the recorded data, the models between BW, BW gain, average daily feed intake and feed/gain ratio and growth days (d) were established. In addition, the incidences of pox-like macula (dermatitis), diarrhea (gastrointestinal disease), cough (respiratory disease), stiff pig (malnutrition), conjunctivitis (eye disease) and foot inflection (trauma) among fattening pigs were also investigated. [Result] The BW range, average BW, daily BW gain, breeding days, daily feed intake range, average daily feed intake, staged feed intake, accumulated feed intake, feed/gain ratio and accumulated feed/gain ratio of different-day-old pigs were studied, respectively. Four dynamic models were established for the growth of pigs: (1) the BW (y)-age (x) mod- el: y=0.758 9x-19.883 (3=0.993 7); (2) the BW gain (y)-age (x) model: y=1.039 5x05051 (F=0.885 4); (3) the average daily feed intake (y)-age (x) model: y=0.023 5x-0.334 3 (F=0.991 7); (4) the feed/gain ratio (y)-age (x) model: y=0.022x+0.427 8 (P=0.988 5). Based on these models, the corresponding theoretical growth value of pigs at different growth stage could be predicted. The main diseases occurred among the swinery in the large-scale microbial fermentation bed piggery included pox-like macula (dermatitis), diarrhea (gastrointestinal disease), cough (respiratory disease), stiff pig (mal- nutrition), conjunctivitis (eye disease) and foot inflection (trauma). The deadly infec- tious diseases had been not found among the pigs. [Conclusion] When the actual BW, BW gain, average daily feed intake and feed/gain ratio were all lower than the theoretical values predicted by the models, the management should be enhanced. The average daily feed intake of 60 to 65-day-old pigs was lower than the theoretic value, indicating that the pigs could not adapt nicely to the fermentation bed at the very early stage. When the pigs grew up to 70 to 75 d old, the average daily feed intake was higher than the theoretical value, indicating that the pigs had adapted to the fermentation bed. In particularly, average daily feed intake of 75-day-old pigs was higher than the theoretical value by 21%. It was suggested the fermentation bed was conducive to the growth of pigs. Considering the occurrence of diseases among pigs, the overall incidence was relatively low. The incidence of each disease was all lower than 10% with little difficulty in treating. If the management of mattress was strength- ened, such as paying attention to feeding and keeping water clean, many diseases could heal by themselves.展开更多
The concept of plant community and community classification were expatiated, the study history and actuality were summarized, and the developmental trends of phytocoenology were prospected.
A centrifuge modeling test and a three-dimensional finite element analysis(FEA)of super-long rock-socketed bored pile groups of the Tianxingzhou Bridge are proposed.Based on the similarity theory,different prototypi...A centrifuge modeling test and a three-dimensional finite element analysis(FEA)of super-long rock-socketed bored pile groups of the Tianxingzhou Bridge are proposed.Based on the similarity theory,different prototypical materials are simulated using different indicators in the centrifuge model.The silver sand,the shaft and the pile cap are simulated according to the natural density,the compressive stiffness and the bending stiffness,respectively.The finite element method(FEM)is implemented and analyzed in ANSYS,in which the stress field during the undisturbed soil stage,the boring stage,the concrete-casting stage and the curing stage are discussed in detail.Comparisons in terms of load-settlement,shaft axial force distribution and lateral friction between the numerical results and the test data are carried out to investigate the bearing behaviors of super-long rock-socketed bored pile groups under loading and unloading conditions.Results show that there is a good agreement between the centrifuge modeling tests and the FEM.In addition,the load distribution at the pile top is complicated,which is related to the stiffness of the cap,the corresponding assumptions and the analysis method.The shaft axial force first increases slightly with depth then decreases sharply,and the rate of decrease in rock is greater than that in sand and soil.展开更多
Let π be a group with a unit 1; H is a Hopf π- coalgebra and A is a right π-H-comodule algebra. First, the notion of a two-sided relative (A, H)-Hopf π-comodule is introduced; then it is obtained that Hom A H (...Let π be a group with a unit 1; H is a Hopf π- coalgebra and A is a right π-H-comodule algebra. First, the notion of a two-sided relative (A, H)-Hopf π-comodule is introduced; then it is obtained that Hom A H (M, N) H and HOMA(M, N) are isomorphic as right Hopf π-H-comodules, where Hom A H(M, N) denotes the space of right A-module fight H-comodule morphisms and HOMa (M, N) denotes the rational space of a space Hom A(M, N) of right A-module morphisms. Secondly, the structure theorem of endomorphism algebras of two-sided relative (A, H)-Hopf π--comodules is established; that is, End A H (M)#H and END A(M, N) are isomorphic as fight Hopf π-H-comodules and algebras.展开更多
A mechanics system consisting of three mass points on sphere S 2 is considered. The configuration space of the system is a fibre bundle over S 2 . It is proved that first Chern class of the bundle is -2 c 1...A mechanics system consisting of three mass points on sphere S 2 is considered. The configuration space of the system is a fibre bundle over S 2 . It is proved that first Chern class of the bundle is -2 c 1(γ) where γ is the canonical line bundle over the complex projective space CP 1=S 2 , which shows the bundle is non trivial. The information about the first Chern class makes the cohomology groups and homotopy groups of the configuration space worked out. In addition the effects of these topolo gical properties of the configuration space on the behavior in large scale of the system, as the number of equilibrium positions, periodic orbits and reduced phase space, are discussed.展开更多
基金The National Natural Science Foundation of China(No.12171083,12071070)Qing Lan Project of Jiangsu Province and the Postgraduate Research and Practice Innovation Program of Jiangsu Province(No.KYCX22_0231).
文摘To characterize m-weak group inverses,several algebraic methods are used,such as the use of idempotents,one-side principal ideals,and units.Consider an element a within a unitary ring that possesses Drazin invertibility and an involution.This paper begins by outlining the conditions necessary for the existence of the m-weak group inverse of a.Moreover,it explores the criteria under which a can be considered pseudo core invertible and weak group invertible.In the context of a weak proper*-ring,it is proved that a is weak group invertible if,and only if,a D can serve as the weak group inverse of au,where u represents a specially invertible element closely associated with a D.The paper also introduces a counterexample to illustrate that a D cannot universally serve as the pseudo core inverse of another element.This distinction underscores the nuanced differences between pseudo core inverses and weak group inverses.Ultimately,the discussion expands to include the commuting properties of weak group inverses,extending these considerations to m-weak group inverses.Several new conditions on commuting properties of generalized inverses are given.These results show that pseudo core inverses,weak group inverses,and m-weak group inverses are not only closely linked but also have significant differences that set them apart.
基金Project(50774102)supported by the National Natural Science Foundation of ChinaProject(2004CB619204)supported by the National Basic Research Program of China
文摘To screen the high efficient mixed culture and understand the bioleaching behaviors of mixed culture for low-grade copper sulfide ore bioleaching,ten mixed cultures were collected and screened from different acid mine drainages obtained from sulfide mines of China.The leaching rate was set as criterion to screen the mixed culture and the metagenomic approach.Community genome array(CGA) was used for analyzing the mixed culture microbial community shift during the bioleaching process.The results indicate that the mixed culture obtained from Yinshan(YS) lead-zinc mine in Dexing of Jiangxi province in China reaches the maximum copper extraction(68.89%) during the one bioleaching period of 24 d.CGA results show that YS culture contains nine kinds of bacteria which are belong to six divisions,and the microbial community structure is changing during the bioleaching process.This provides a good way to accelerate the bioleaching process and reveals the microbial community shift during the bioleaching process.
文摘How to restore the destroyed forest after forest fire is a key question that man must face. This paper reviewed the research situation and history on the forest restoration burned blanks and summed up the research methods used into four scales: seed-bank scale, community scale, ecosystem scale and landscape scale. The new technologies such as GIS & Remote Sensing used to vegetation restoration were also summarized. The strategies and developing trend of vegetation restoration research on burned blanks were discussed.
基金TheNationalNaturalScienceFoundationofChina (No .39670 1 36) PhDFund (No .980 5580 8)ofMinistryofEducationP .R .China Center
文摘Amplified fragment length polymorphism(AFLP)was used to analyze 2 populations: Schima superba Gardn. et Champ. and Castanopsis chinensis Hance. across three different communities representing three succession stages, in Dinghu Mountain, China. These two were middle succession species in the lower subtropical broad_leaved forest. Four AFLP primer combinations using total 48 individuals of S. superba provided 24, 40, 27 and 27 reliable bands, of which 15, 23, 23 and 16 were polymorphic, respectively. Similarly, total 48 individuals of C. chinensis provided 27, 20, 33 and 39 reliable bands, of which 12, 5, 15 and 13 were polymorphic respectively. These bands were used as presence/absence data to assess the levels of genetic variation and population structure of those species. From average heterozygosity, S. superba possessed higher molecular variation than C. chinensis . Analysis of molecular variance(AMOVA)indicated that most of the genetic variation of S. superba was due to the differences within population(95.99%, P <0.001), with 4.01% ( P <0.001)genetic variation among population. Similarly, AMOVA indicated the most of the genetic variation of C. chinensis was due to the differences within population(75.36%, P <0.001), with 24.64%( P <0.001)genetic variation among communities(24.64%). DCA(Detrended Correspondence Analysis) analysis showed that the individuals of S. superba from the same community did not cluster together, while the individuals of C. chinensis from the same community roughly cluster together. The above results reflected the biological characteristics of the two different species suggesting the significant effect of microenvironment of different community on population differentiation and its relationship of which to forest succession resulted in genetic divergence.
基金supported by research grants of the National Basic Research Program of China (2007CB815700 2006CB102100)Bureau of Science and Technology of Yunnan Province, and Natural Science Foundation of China (30621092)
文摘To assess the genetic diversity between randomly and selectively bred populations,we sequenced 438 bp of the mitochondrial DNA control region from 102 pigs.These samples represented four native pig breeds,one nucleus and one conservation herd from Yunnan,China.Twenty haplotypes with sixteen polymorphic sites were identified.The number of haplotypes in the nucleus herd of Saba pig and the conservation herd of Banna miniature pig were restricted to three and one,respectively,while the randomly bred pig populations exhibited over six haplotypes.Notably,haplotype diversity in randomly bred populations was significantly greater than the selectively bred populations(h=0.732 vs.0.425 and 0,exact test,P≤0.0036).These findings demonstrate that selective breeding generated low genetic diversity compared to randomly bred pig breeds.A timely intervention and well programmed breeding approach would stop further genetic diversity reduction in the nucleus and conservation herds of native pig breeds.Otherwise,selective breeding would dramatically reduce genetic diversity in only several years,indicating that sharp contradictions exist between breeding,conservation and genetic diversity.Genetic relationships are discussed based on net genetic distances among pig populations.
文摘This study was designed to introduce a new method of estimating group size and composition of black-andwhite snub-nosed monkeys (Rhinopithecus bieti ) on the basis of faecal amount at sleeping sites at Mt. Baima Nature Reserve. The monkeys spend nights in the form of one-male, multi-female units (OMUs) and all-male units (AMU), and their faecal pellets can be classified into three categories: adult males (the largest), adult females (moderate) and immatures (the smallest) based on their size. Total pellets were counted under sleeping trees used for two nights at Nanren village (99°04′E, 28°34′N, northwest of Yunnan Province, China) in each of four seasons in 2000- 2001. Moreover, data on group composition were collected when the monkeys were passing through an open gully in November 2001. Since the number of adults in OMUs shows a positive significant correlation with the amount of pellets amount in each season, the mean number of feces produced per night per individual is the slope of the regression lines. Thus, group size and composition can be relatively reliably and accurately estimated by the faeces under trees compared with the previous methods of estimation, including the use of monkeys' activities and tracks such as broken branches on steep slopes, in deep gorges and under lower visibility. The use of pellets for population estimates displayed 9.4% deviation in regards to population size of adult females. Some causes of the bias were also discussed. The method might be applicable to other monkey groups of this species if their habitats and main foods are similar to those of the study group.
基金the Ministry of Education (No. NCET-04-0640)the National Natural Science Foundation of China (No. 30571442).
文摘Microsatellite DNA technique was used to detect the genetic variation between five hatchery populations of the Pacific oyster from China and two wild populations from Japan. Seven microsatellite loci screened in this study showed high polymorphism in both hatchery and wild populations, as observed in an average number of allele per locus (19.1-29.9) and average expected heterozygosity (0.916-0.958). No significant difference in average allelic richness or expected heterozygosity was observed between Chinese hatchery populations and Japanese wild populations. Pairwise Fsr values and heterogeneity tests of allele frequencies showed significant genetic differentiation between all populations. According to the neighbor-joining tree constructed on the basis of the Dc distance, the seven populations fell into three groups showing a clear division between hatchery and wild populations, and between the northern and southern hatchery populations. Assignment tests correctry assigned high percentages (97%-100%) of individuals to their original populations and demonstrated the feasibility of microsatellite analysis for discrimination between populations. The information obtained in this study is useful for designing suitable management guidelines and selective breeding programs for the Pacific oyster in China.
文摘The main purpose of this study was to examine the effects of plant species diversity and functional composition (the identity of the plant functional groups) on ecosystem stability of Stipa, communities in the Inner Mongolia Plateau. The research work was based on a 12-year study (from 1984 to 1995) of species abundance, diversity, and primary productivity of four Stipa communities, i.e. S. baicalensis Roshev., S. grandis P. Smirn., S, krylovii Roshev., and S. klemenzii Roshev. respectively. The Shnnon-Wiener index was used as a measurement of plant diversity, while functional composition was used to differentiate the functional groups that were included in the communities. The plant species of four Stipa communities were classified into functional groups based on the differences in life forms and ecological groups, which influence their performance in resource requirements, seasonality of growth, tolerance to water stress, and life history. Plant species were classified into five functional groups based on their differences in life form, shrubs and half shrubs, perennial bunch grasses, perennial rhizome grasses, forbs, annuals and biennials. Based on their differences in water requirement these species were classified into four functional groups: xerads, intermediate xerads, intermediate mesophytes, and mesophytes. The results showed: 1) Plant species diversity stabilized ecosystem processes. Shannon-Wiener index were 2.401 4, 2.172 0, 1.624 8, 0.354 3 from S. baicalensis community to S. grandis, S. krylovii and S. klemenzii community, respectively. The dynamics of the aboveground net primary productivity (ANPP) for a 12-year's period showed a reverse pattern, the coefficients of variation of the four communities were 21.94%, 20.63%, 29.21% and 39.72% respectively. 2) The Life form functional group component of diversity was a greater determinant of the ecosystem processes than the species component of diversity. The effects of perennial bunch grasses, perennial rhizome grasses and forbs on community stability were highly significant. 3) The ecological group component of diversity was also a great determinant of the ecosystem processes. The effects of xerads, intermediate xerads, and mesophytes on community stability were also very strong.
基金Supported by the Key New Products Development Program of Science and Technology Agency of Yunnan Province(2011BB012)~~
文摘[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of major and auxiliary nec-tariferous plants, six Apis mel ifera colonies were selected for measure the number of eggs, larvae, pupae and adult bees from Jan. to Dec. in 2012; based on that, their annual change curves were also plotted. [Result] The results showed that there were three peaks of the total number of A. mel ifera workers throughout the year:the first occurred on May 15th, with bees developed into an ideal population for col-lecting pomegranate nectar, and the second and third peaks occurred on July 15th and Oct. 15th, respectively, with bees developed into an ideal population for col ect-ing E. ciliate (Thuab) Hyland. [Conclusion] Prevention of Varroa jacobsoni should be carried out with two or more types of acaricides at the late nectar flow stages of the two nectariferous plants(pomegranate and E. ciliate (Thuab) Hyland) when there was a nectar deficiency. Prevention of Tropilaelaps clareae should be timely per-formed with sublimed sulfur in conjunction with acaricides. This study provides a theoretical basis for the high-quality and high-yielding production of honey, as wel as for the product safety.
文摘A presentation of hyperbolic unitary group is an important part in the unitary group. The group KG 2,n (R) plays an elementary role in presentation of unitary group. It is proved that KG 2,n(R)=1 for n≥2 over a ring R with division ring of quotients, using a new method, and a presentation of GE n(R) is given.
文摘The characteristics of macrofauna communities in three mangrove assemblages [Avicennia marina+Acgiceras corniculatum (MC)community, A.corniculatum (C) community and Bruguiera gymnorrhiza+A.corniculatum (GC) community] were studied in Zhanjiang Mangrove Nature Reserves during 2005 and 2006. Of the three mangrove assemblages, the macrofauna species number, density, biomass, Richness index and Shannon-Wiener index were the highest, and the Simpson dominance index was medial at MC community. However the Pielou Evenness index of MC community was slightly lower than that at C community. At C community, the number of macrofauna species obviously reduced, especially infaunal, caving and adhering life forms, and the biomass and density were the lowest. Because of the even distribution of individuals of different species, the Simpson dominance index was the lowest and the evenness index was the highest. Although the Richness index at C community was slightly lower than that at MC community, the Shannon-Wiener index was near to that at MC community. At GC community, the number of macrofauna species, especially infaunal and caving life forms, continued to decrease comparing C community, but the biomass and density increased slightly. As the distribution of individuals of different species was uneven, the Simpson dominance index was the highest and the Pielou Evenness index was the lowest. Furthermore, the Richness index dropped to the lowest. The Shannon-Wiener index also dropped accordingly to the lowest. The dominant life forms of MC were infaunal and caving, while those of C and GC community were both caving. The ratio of the GS/GSB of macrofauna communities in the three mangrove assemblages were 0.48, 0.63 and 0.80, respectively. The community structures at the same mangrove assemblages were all quite similar, with those at GC community being most similar. However, there were obvious differences among the community structures at the three different mangrove assemblages. These results implied that the different mangrove assemblages had different affects on the macrofauna communities and shed light on the macrofauna adaptation capability to specific habitats.
文摘The competition-density effect of plant populations is of significance in theory and practice of forest management and has been studied for long time. The differences between the two reciprocal equations of the competition-density effect in nonself-thinning populations and self-thinning populations were analyzed theoretically. This supplies a theoretical basis for analyzing the dynamics of forest populations and evaluating the effect of forest management.
基金The National Natural Science Foundation of China (No. 39970591)
文摘Dovetree (Davidia involucrate), one of the first-class protective plants in China, is a relic species of paleotropical kingdom in Tertiary period, belonging toDavidiaceae with a single genus. In recent years, the increase of regional developing projects has led to a sharp decrease of this ancient and rare plant in naturally distributed habitats and natural population. In this paper, the biological and ecological characteristics of Dovetree were described, and the geographically distributed condition of this species in different geologic periods as well as the major reasons for dynamic changes of its population were systematically analyzed in accordance with field researches and references. The investigations conducted in different years by setting up standard sample plots showed that the population number of Dovetree increased yearly in the areas without human interference but decreased yearly in the areas with human interference. With the increase of population density and human activities decreased as the logarithmic curve:Y=?100.7ln(x)+178.09, and it has turned from a dominant population into an endangered population. Based on the former and present studies on Dovetree, some protection strategies were put foreword for protecting this ancient and rare species. Keywords Davidia involucrate - Dovetree - Geographical Distribution - Biological Characteristics - Protection Policy CLC number S718.4 Document code A Article ID 1007-662X(2004)01-0039-06 Foundation Item: This research was coordinated by the National Natural Science Foundation of China (No. 39970591)Biography: Wu Gang (1965-), Male, Professor in Key Laboratory of Systems Ecology, Research Center for Eco Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.Responsible editor: Chai Ruihai
基金Supported by International Science and Technology Cooperation Project of China(2012DFA31120)Special Fund for Agro-scientific Research in the Public Interest(201303094)National Key Technology Research and Development Program(2012BAD14B15)~~
文摘[Objective] The behavior of eating, drinking, defecating and peeing of 1 500 pigs in a large-scale microbial fermentation bed-equipped piggery was observed. We hoped to find some simple indicators that could reflect the health status of swinery and to provide experience for the swinery performance management in large-scale microbial fermentation bed-equipped piggery. [Method] The body weight (BW), daily BW gain, feed intake and other indicators of different-day-old pigs were recorded in details. Based on the recorded data, the models between BW, BW gain, average daily feed intake and feed/gain ratio and growth days (d) were established. In addition, the incidences of pox-like macula (dermatitis), diarrhea (gastrointestinal disease), cough (respiratory disease), stiff pig (malnutrition), conjunctivitis (eye disease) and foot inflection (trauma) among fattening pigs were also investigated. [Result] The BW range, average BW, daily BW gain, breeding days, daily feed intake range, average daily feed intake, staged feed intake, accumulated feed intake, feed/gain ratio and accumulated feed/gain ratio of different-day-old pigs were studied, respectively. Four dynamic models were established for the growth of pigs: (1) the BW (y)-age (x) mod- el: y=0.758 9x-19.883 (3=0.993 7); (2) the BW gain (y)-age (x) model: y=1.039 5x05051 (F=0.885 4); (3) the average daily feed intake (y)-age (x) model: y=0.023 5x-0.334 3 (F=0.991 7); (4) the feed/gain ratio (y)-age (x) model: y=0.022x+0.427 8 (P=0.988 5). Based on these models, the corresponding theoretical growth value of pigs at different growth stage could be predicted. The main diseases occurred among the swinery in the large-scale microbial fermentation bed piggery included pox-like macula (dermatitis), diarrhea (gastrointestinal disease), cough (respiratory disease), stiff pig (mal- nutrition), conjunctivitis (eye disease) and foot inflection (trauma). The deadly infec- tious diseases had been not found among the pigs. [Conclusion] When the actual BW, BW gain, average daily feed intake and feed/gain ratio were all lower than the theoretical values predicted by the models, the management should be enhanced. The average daily feed intake of 60 to 65-day-old pigs was lower than the theoretic value, indicating that the pigs could not adapt nicely to the fermentation bed at the very early stage. When the pigs grew up to 70 to 75 d old, the average daily feed intake was higher than the theoretical value, indicating that the pigs had adapted to the fermentation bed. In particularly, average daily feed intake of 75-day-old pigs was higher than the theoretical value by 21%. It was suggested the fermentation bed was conducive to the growth of pigs. Considering the occurrence of diseases among pigs, the overall incidence was relatively low. The incidence of each disease was all lower than 10% with little difficulty in treating. If the management of mattress was strength- ened, such as paying attention to feeding and keeping water clean, many diseases could heal by themselves.
文摘The concept of plant community and community classification were expatiated, the study history and actuality were summarized, and the developmental trends of phytocoenology were prospected.
基金The Natural Science Foundation of Hubei Province(No.2007ABA094)
文摘A centrifuge modeling test and a three-dimensional finite element analysis(FEA)of super-long rock-socketed bored pile groups of the Tianxingzhou Bridge are proposed.Based on the similarity theory,different prototypical materials are simulated using different indicators in the centrifuge model.The silver sand,the shaft and the pile cap are simulated according to the natural density,the compressive stiffness and the bending stiffness,respectively.The finite element method(FEM)is implemented and analyzed in ANSYS,in which the stress field during the undisturbed soil stage,the boring stage,the concrete-casting stage and the curing stage are discussed in detail.Comparisons in terms of load-settlement,shaft axial force distribution and lateral friction between the numerical results and the test data are carried out to investigate the bearing behaviors of super-long rock-socketed bored pile groups under loading and unloading conditions.Results show that there is a good agreement between the centrifuge modeling tests and the FEM.In addition,the load distribution at the pile top is complicated,which is related to the stiffness of the cap,the corresponding assumptions and the analysis method.The shaft axial force first increases slightly with depth then decreases sharply,and the rate of decrease in rock is greater than that in sand and soil.
基金The Research and Innovation Project for College Graduates of Jiangsu Province(No.CXLX_0094)the Natural Science Foundation of Chuzhou University(No.2010kj006Z)
文摘Let π be a group with a unit 1; H is a Hopf π- coalgebra and A is a right π-H-comodule algebra. First, the notion of a two-sided relative (A, H)-Hopf π-comodule is introduced; then it is obtained that Hom A H (M, N) H and HOMA(M, N) are isomorphic as right Hopf π-H-comodules, where Hom A H(M, N) denotes the space of right A-module fight H-comodule morphisms and HOMa (M, N) denotes the rational space of a space Hom A(M, N) of right A-module morphisms. Secondly, the structure theorem of endomorphism algebras of two-sided relative (A, H)-Hopf π--comodules is established; that is, End A H (M)#H and END A(M, N) are isomorphic as fight Hopf π-H-comodules and algebras.
文摘A mechanics system consisting of three mass points on sphere S 2 is considered. The configuration space of the system is a fibre bundle over S 2 . It is proved that first Chern class of the bundle is -2 c 1(γ) where γ is the canonical line bundle over the complex projective space CP 1=S 2 , which shows the bundle is non trivial. The information about the first Chern class makes the cohomology groups and homotopy groups of the configuration space worked out. In addition the effects of these topolo gical properties of the configuration space on the behavior in large scale of the system, as the number of equilibrium positions, periodic orbits and reduced phase space, are discussed.