The nervous system function requires a precise but plastic neural architecture.The neuronal shape dictates how neurons interact with each other and with other cells,being the morphology of dendrites and axons the cent...The nervous system function requires a precise but plastic neural architecture.The neuronal shape dictates how neurons interact with each other and with other cells,being the morphology of dendrites and axons the central determinant of the functional properties of neurons and neural circuits.The topological and structural morphology of axons and dendrites defines and determines how synapses are conformed.The morphological diversity of axon and dendrite arborization governs the neuron’s inputs,synaptic integration,neuronal computation,signal transmission,and network circuitry,hence defining the particular connectivity and function of the different brain areas.展开更多
Ni-Fe/Cu/Co/Cu multilayered nanowire arrays were electrodeposited into anodic aluminum oxide template by using dual-bath method at room temperature. Scanning electron microscopy and transmission electron microscopy we...Ni-Fe/Cu/Co/Cu multilayered nanowire arrays were electrodeposited into anodic aluminum oxide template by using dual-bath method at room temperature. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology and structure of the multilayered nanowire arrays. Vibrating sample magnetometer and physical property measurement system were used to measure their magnetic and giant magnetoresistance （GMR） properties. The effect of sub-layer thickness on the magnetic and GMR properties was investigated. The results indicate that magnetic properties of electmdeposited nanowires are not affected obviously by Cu layer thickness, while magnetic layers （Ni-Fe and Co layers） have significant influence. In addition, GMR ratio presents an oscillatory behavior as Cu layer thickness changes. The magnetic and GMR properties of the multilayered nanowire arrays are optimum at room temperature for the material structure of Ni-Fe （25 nm）/Cu （15 nm）/Co （25 nm）/Cu （15 nm） with 30 deposition cycles.展开更多
Background Salmonella enterica serovar Enteritidis(S.Enteritidis)is a global foodborne pathogen that poses a significant threat to human health,with poultry being the primary reservoir host.Therefore,addressing S.Ente...Background Salmonella enterica serovar Enteritidis(S.Enteritidis)is a global foodborne pathogen that poses a significant threat to human health,with poultry being the primary reservoir host.Therefore,addressing S.Enteritidis infections in poultry is crucial to protect human health and the poultry industry.In this study,we investigated the effect of co-housing Arbor Acres(AA)chickens,a commercial breed susceptible to S.Enteritidis,with Tibetan chickens,a local breed resistant to S.Enteritidis infection,on the resistance of the latter to the pathogen.Results Ninety-six 1-day-old Tibetan chickens and 961-day-old AA chickens were divided into a Tibetan chicken housed alone group(n=48),an AA chicken housed alone group(n=48),and a co-housed group(48 birds from each breed for 2 cages).All birds were provided the same diet,and the experimental period lasted 14 d.At d 7,all chickens were infected with S.Enteritidis,and samples were collected at 1-,3-,and 7-day-post-infection.We found that the body weight of AA chickens significantly increased when co-housed with Tibetan chickens at 1-and 3-day-post-infection(P<0.05).In addition,the cecal S.Enteritidis load in AA chickens was significantly reduced at 1-,3-,and 7-day-post-infection(P<0.05).Furthermore,the inflammatory response in AA chickens decreased,as evidenced by the decreased expression of proinflammatory cytokines NOS2,TNF-α,IL-8,IL-1β,and IFN-γin their cecal tonsils(P<0.05).Co-housing with Tibetan chickens significantly increased the height of villi and number of goblet cells(P<0.05),as well as the expression of claudin-1(P<0.05),a tight junction protein,in the jejunum of AA chickens.Further analysis revealed that co-housing altered the gut microbiota composition in AA chickens;specifically,the relative abundances of harmful microbes,such as Intestinimonas,Oscillibacter,Tuzzerella,Anaerotruncus,Paludicola,and Anaerofilum were reduced(P<0.05).Conclusions Our findings indicate that co-housing with Tibetan chickens enhanced the resistance of AA chickens to S.Enteritidis infection without compromising the resistance of Tibetan chickens.This study provides a novel approach for Salmonella control in practical poultry production.展开更多
The community characteristics of natural secondary forests on the north slope of Changbai Mountain after selective cutting were investigated, and the dynamics of arborous species diversity during the restoration perio...The community characteristics of natural secondary forests on the north slope of Changbai Mountain after selective cutting were investigated, and the dynamics of arborous species diversity during the restoration period of 28 years were studied. The results showed that the arborous species richness (S) had little change and kept the range of 18-22 all along, the Simpson index (D) of the secondary layer and regeneration layer and whole stand had similar trends of change, but that of the canopy layer descended slowly in initial 15 years and had little change later, and the change of diversity index was not obvious and the Shannon-Wiener index (H? fluctuated in a very small scopes (H±10%).展开更多
Since the first electron micrograph of“lace-like structures”over 75 years ago,the endoplasmic reticulum(ER)is now viewed as a highly dynamic,constantly remodeling,continuous network of tubules and cisternae that pla...Since the first electron micrograph of“lace-like structures”over 75 years ago,the endoplasmic reticulum(ER)is now viewed as a highly dynamic,constantly remodeling,continuous network of tubules and cisternae that plays an important role in a broad range of cellular activities from calcium regulation to protein synthesis and trafficking.In neurons,the ER extends from the soma through the axon to presynaptic terminals,and throughout the dendritic arbor into as many as half of all postsynaptic dendritic spines at any given time(Falahati et al.,2022).展开更多
AIM:To investigate the clinical characteristics and treatment outcomes,including visual function and overall survival(OS)of patients with ocular adnexal diffuse large B-cell lymphoma(OA-DLBCL).METHODS:This retrospecti...AIM:To investigate the clinical characteristics and treatment outcomes,including visual function and overall survival(OS)of patients with ocular adnexal diffuse large B-cell lymphoma(OA-DLBCL).METHODS:This retrospective cohort study enrolled 29 patients diagnosed with OA-DLBCL based on histopathological biopsy between 2006 and 2023.Patients were stratified into two subgroups:primary OA-DLBCL(no prior history of lymphoma)and secondary OA-DLBCL(history of DLBCL at non-ocular adnexal sites).OS was defined as the time interval from OA-DLBCL diagnosis to death from any cause.Survival analysis was performed using the Kaplan–Meier method,and prognostic factors affecting OS were identified using multivariate Cox proportional hazards regression with a stepwise selection approach.RESULTS:The cohort included 24 patients with primary OA-DLBCL(13 males,11 females;mean age:61.36±18.29y)and 5 patients with secondary OA-DLBCL(2 males,3 females;mean age:50.94±18.17y).Among the primary OA-DLBCL subgroup,12 patients(50%)presented with advanced disease(Ann Arbor stage IIIE–IV),and 16 patients(66%)were classified as T4 disease according to the tumor-node-metastasis(TNM)staging system.The mean final visual acuity was 1.72±1.10 in the primary group and 0.90±1.18 in the secondary group.The 5-year OS rate for the entire cohort was 27.7%.Multivariate analysis identified five factors significantly associated with poor survival outcomes:epiphora[adjusted hazard ratio(aHR),36.95],atherosclerotic cardiovascular disease(aHR,10.08),human immunodeficiency virus(HIV)infection(aHR,12.47),M1 stage(aHR,6.99),and secondary OA-DLBCL(aHR,6.03;all P<0.05).The median OS was 1.68y for primary OA-DLBCL and 1.12y for secondary OA-DLBCL.CONCLUSION:A substantial proportion of patients with primary OA-DLBCL present with advanced-stage disease at diagnosis.Epiphora,atherosclerotic cardiovascular disease,HIV infection,M1 stage,and secondary OA-DLBCL are independent prognostic factors for poor survival outcomes.These findings emphasize the urgent need for optimized therapeutic strategies and early screening protocols to improve the management of OA-DLBCL,particularly in developing countries.展开更多
For a long time,forestry primarily had industrial goals.Volume of wood production was the main criterion of forestry efficacy,and thus rapid-growing arboreal species were cultivated in natural forests.More recently,na...For a long time,forestry primarily had industrial goals.Volume of wood production was the main criterion of forestry efficacy,and thus rapid-growing arboreal species were cultivated in natural forests.More recently,nature protection has become one of forestry＇s goals.Unfortunately,some introduced,rapid-growing species became aggressive components of natural ecological systems during the interim.In this paper,we first describe a method that we developed to categorize aggressiveness of invasive arboreal plants in natural forest ecosystems of Kazakhstan.We then apply this new scheme to monitoring data of invasive arboreal plants to provide an insight into the invasion potential of different species in the fruit forests of Southeast Kazakhstan.展开更多
A linear forest is a forest whose components are paths. The linear arboricity la （G） of a graph G is the minimum number of linear forests which partition the edge set E（G） of G. The Cartesian product G□H of two g...A linear forest is a forest whose components are paths. The linear arboricity la （G） of a graph G is the minimum number of linear forests which partition the edge set E（G） of G. The Cartesian product G□H of two graphs G and H is defined as the graph with vertex set V（G□H） = {（u, v）｜ u ∈V（G）, v∈V（H） } and edge set E（G□H） = { （ u, x） （ v, Y）｜u=v and xy∈E（H）, or uv∈E（G） and x=y}. Let Pm and Cm,, respectively, denote the path and cycle on m vertices and K, denote the complete graph on n vertices. It is proved that （Km□Pm）=[n＋1/2]for m≥2,la（Km□Cm）=[n＋2/2],and la（Km□Km）=[n＋m-1/2]. The methods to decompose these graphs into linear forests are given in the proofs. Furthermore, the linear arboricity conjecture is true for these classes of graphs.展开更多
In this paper, secondary forest of Pinus massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest were taken as research objects, to explore carbon reserve of arbor layer and its spatial dis...In this paper, secondary forest of Pinus massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest were taken as research objects, to explore carbon reserve of arbor layer and its spatial distribution characteristics. At different succession stages, the sequence of organic carbon content in each organ was secondary forest of P. massoniana > coniferous-broad-leaved mixed forest> broad-leaved evergreen forest. Carbon reserve of arbor layer was the highest in broad-leaved evergreen forest, which was 129.34 t/hm 2, followed by coniferous-broad-leaved mixed forest (95.83 t/hm 2), and the minimum was 85.27 t/hm 2 in secondary forest of P. massoniana . In each stand type, the sequence of carbon reserve of each organ in arbor layer was trunk>root>branch>leaf>bark. Carbon reserve of arbor layer mainly concentrated in trunk, and the proportion to carbon reserve of arbor layer declined from secondary forest of P. massoniana to broad-leaved evergreen forest, while it had increasing relationship in root. In secondary forest of P. massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest, individual with the diameter more than 20 cm accounted for the majority of carbon reserve in the arbor layer.展开更多
Pine wilt disease caused by pine wood nema-todes is a deadly disease of the genus Pinus requiring strong quarantine measures.Since its discovery,it has been widely distributed throughout the world.China is one of the ...Pine wilt disease caused by pine wood nema-todes is a deadly disease of the genus Pinus requiring strong quarantine measures.Since its discovery,it has been widely distributed throughout the world.China is one of the coun-tries with a severe rate of infections due to its abundant pine resources.In this study,nematode-trapping fungi were collected from pine trees in Ninghai City,Zhejiang Prov-ince,which is the key area of pine wilt control in Febru-ary,May,September,October and November.The results showed that nematode-trapping fungi of pine are abundant,especially the number and species detected in each month and are quite different;species of fungi in July,Septem-ber and November were more numerous and had higher separation rates.The dominant species in November was Arthrobotrys oligospora followed by Arthrobotrys cladodes;July and September it was A.cladodes.In each part of the tree,A.cladodes was the most widely distributed with a high separation rate.Therefore,it is the dominant fungal species in the area.Arboreal Bursaphelenchus xylophilus-trapping fungi are dependent on pine wood nematodes,and none were isolated from healthy pine trees.More arboreal B.xylophilus-trapping fungi were found under the bark than in the xylem.There is a close relationship between arboreal B.xylophilus-trapping fungi and pine wood nematodes.How to make use of these resources to reduce the damage of pine wood nematode fusarium is the focus of future research.展开更多
The seasonality and relative abundance of arboreal ant species were studied in the oil palm plantations of CSIR-OPRI at Kusi in order to identify the different arboreal ant species in the oil palm canopy and their pos...The seasonality and relative abundance of arboreal ant species were studied in the oil palm plantations of CSIR-OPRI at Kusi in order to identify the different arboreal ant species in the oil palm canopy and their possible interaction with other fauna and flora. Chemical knockdown and field observation and were used in the data collection. Chemical knockdown study was used to collect data on the relative abundance of the ants with application of a synthetic pyrethroid. Field observation was used to study the nesting behaviour, types of nests and where they were built as well as the interaction between the ant species. The fields which were of ages of 8, 11 and 14 years were one hectare containing 143 palms. Chemical knockdown and ant colony studies revealed higher abundance of arboreal ant species on the I 1 years followed by the 8 years and 14 years fields in that order. Oecophylla longinoda was abundant on the I 1-and 14-year-old fields while Crematogaster sp. was the most abundant species on the 8-year old fields. Relatively high numbers of the ant species were encountered in the dry months of study. Positive interaction indicated coexistence between O. longinoda and Crematogaster sp. Interaction between Crematogaster sp. and Tetramorium sp. was antagonistic. Similarly, O. longinoda and Tetramorium sp. were antagonistic to each other. The high abundance and diversity hold promise for the potential use of these ant species as biocontrol agents in an integrated pest management system for the management of the oil palm leaf miner.展开更多
In this paper,the Pinus massoniana forest in the early stage of succession,the coniferous broad-leaved mixed forest in the middle stage of succession,and the evergreen broad-leaved forest in the late stage of successi...In this paper,the Pinus massoniana forest in the early stage of succession,the coniferous broad-leaved mixed forest in the middle stage of succession,and the evergreen broad-leaved forest in the late stage of succession were studied,and the biomass and its spatial distribution characteristics of the tree layer in different succession stages of the ecosystem were discussed.The results showed that the biomass of the arbor layer was the highest in the evergreen broad-leaved forest,which was 292.51 t/hm2,followed by the coniferous and broad-leaved mixed forest,which was 206.87 t/hm2,and the Pinus massoniana forest,which was 171.76 t/hm^(2).The biomass of trunks accounted for the largest proportion in the total biomass of the arbor layer,which reduced from the Pinus massoniana forest to the evergreen broad-leaved forest.The proportion of the biomass of roots in the total biomass of the arbor layer increased from the Pinus massoniana forest to the evergreen broad-leaved forest.The biomass of the diameter class above 20 cm in the Pinus massoniana forest,the coniferous and broad-leaved mixed forest and the evergreen broad-leaved forest accounted for a large proportion of total biomass.展开更多
A star forest is a forest whose components are stars. The star arboricity of a graph G,denoted by sa（ G）,is the minimum number of star forests needed to decompose G. Let k be a positive integer. A k-star forest is a...A star forest is a forest whose components are stars. The star arboricity of a graph G,denoted by sa（ G）,is the minimum number of star forests needed to decompose G. Let k be a positive integer. A k-star forest is a forest whose components are stars of order at most k ＋ 1. The k-star arboricity of a graph G,denoted by sak（ G）,is the minimum number of k-star forests needed to decompose G. In this paper,it is proved that if any two vertices of degree 3 are nonadjacent in a subcubic graph G then sa2（ G） ≤2.For general subcubic graphs G, a polynomial-time algorithm is described to decompose G into three 2-star forests. For a tree T and[Δ k, T）/k]t≤ sak（ T） ≤[Δ（ T）- 1/K]＋1,where Δ（ T） is the maximum degree of T.kMoreover,a linear-time algorithm is designed to determine whether sak（ T） ≤m for any tree T and any positive integers m and k.展开更多
基金supported by the Wellcome Trust(grant No.103852).
文摘The nervous system function requires a precise but plastic neural architecture.The neuronal shape dictates how neurons interact with each other and with other cells,being the morphology of dendrites and axons the central determinant of the functional properties of neurons and neural circuits.The topological and structural morphology of axons and dendrites defines and determines how synapses are conformed.The morphological diversity of axon and dendrite arborization governs the neuron’s inputs,synaptic integration,neuronal computation,signal transmission,and network circuitry,hence defining the particular connectivity and function of the different brain areas.
基金Supported by the Natural Science Foundation of Tianjin,China(08JCZDJC17400)
文摘Ni-Fe/Cu/Co/Cu multilayered nanowire arrays were electrodeposited into anodic aluminum oxide template by using dual-bath method at room temperature. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology and structure of the multilayered nanowire arrays. Vibrating sample magnetometer and physical property measurement system were used to measure their magnetic and giant magnetoresistance （GMR） properties. The effect of sub-layer thickness on the magnetic and GMR properties was investigated. The results indicate that magnetic properties of electmdeposited nanowires are not affected obviously by Cu layer thickness, while magnetic layers （Ni-Fe and Co layers） have significant influence. In addition, GMR ratio presents an oscillatory behavior as Cu layer thickness changes. The magnetic and GMR properties of the multilayered nanowire arrays are optimum at room temperature for the material structure of Ni-Fe （25 nm）/Cu （15 nm）/Co （25 nm）/Cu （15 nm） with 30 deposition cycles.
基金supported by the Earmarked fund for China Agriculture Research System of MOF and MARA(Grant No.CARS-41-G01).
文摘Background Salmonella enterica serovar Enteritidis(S.Enteritidis)is a global foodborne pathogen that poses a significant threat to human health,with poultry being the primary reservoir host.Therefore,addressing S.Enteritidis infections in poultry is crucial to protect human health and the poultry industry.In this study,we investigated the effect of co-housing Arbor Acres(AA)chickens,a commercial breed susceptible to S.Enteritidis,with Tibetan chickens,a local breed resistant to S.Enteritidis infection,on the resistance of the latter to the pathogen.Results Ninety-six 1-day-old Tibetan chickens and 961-day-old AA chickens were divided into a Tibetan chicken housed alone group(n=48),an AA chicken housed alone group(n=48),and a co-housed group(48 birds from each breed for 2 cages).All birds were provided the same diet,and the experimental period lasted 14 d.At d 7,all chickens were infected with S.Enteritidis,and samples were collected at 1-,3-,and 7-day-post-infection.We found that the body weight of AA chickens significantly increased when co-housed with Tibetan chickens at 1-and 3-day-post-infection(P<0.05).In addition,the cecal S.Enteritidis load in AA chickens was significantly reduced at 1-,3-,and 7-day-post-infection(P<0.05).Furthermore,the inflammatory response in AA chickens decreased,as evidenced by the decreased expression of proinflammatory cytokines NOS2,TNF-α,IL-8,IL-1β,and IFN-γin their cecal tonsils(P<0.05).Co-housing with Tibetan chickens significantly increased the height of villi and number of goblet cells(P<0.05),as well as the expression of claudin-1(P<0.05),a tight junction protein,in the jejunum of AA chickens.Further analysis revealed that co-housing altered the gut microbiota composition in AA chickens;specifically,the relative abundances of harmful microbes,such as Intestinimonas,Oscillibacter,Tuzzerella,Anaerotruncus,Paludicola,and Anaerofilum were reduced(P<0.05).Conclusions Our findings indicate that co-housing with Tibetan chickens enhanced the resistance of AA chickens to S.Enteritidis infection without compromising the resistance of Tibetan chickens.This study provides a novel approach for Salmonella control in practical poultry production.
基金This research was supported by Institute of Shenyang Applied Ecology CAS (SCXMS0101),National Key Technologies R&D Program (NKTRDP. 2002BA516A20) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education
文摘The community characteristics of natural secondary forests on the north slope of Changbai Mountain after selective cutting were investigated, and the dynamics of arborous species diversity during the restoration period of 28 years were studied. The results showed that the arborous species richness (S) had little change and kept the range of 18-22 all along, the Simpson index (D) of the secondary layer and regeneration layer and whole stand had similar trends of change, but that of the canopy layer descended slowly in initial 15 years and had little change later, and the change of diversity index was not obvious and the Shannon-Wiener index (H? fluctuated in a very small scopes (H±10%).
基金supported by AHA Career Development Award 938683 (to PJD)NIH grant R01MH123700 (to MLD)
文摘Since the first electron micrograph of“lace-like structures”over 75 years ago,the endoplasmic reticulum(ER)is now viewed as a highly dynamic,constantly remodeling,continuous network of tubules and cisternae that plays an important role in a broad range of cellular activities from calcium regulation to protein synthesis and trafficking.In neurons,the ER extends from the soma through the axon to presynaptic terminals,and throughout the dendritic arbor into as many as half of all postsynaptic dendritic spines at any given time(Falahati et al.,2022).
基金Supported by the Faculty of Medicine,Prince of Songkla University.Wainipitapong S has received grants from the Faculty of Medicine,Prince of Songkla University。
文摘AIM:To investigate the clinical characteristics and treatment outcomes,including visual function and overall survival(OS)of patients with ocular adnexal diffuse large B-cell lymphoma(OA-DLBCL).METHODS:This retrospective cohort study enrolled 29 patients diagnosed with OA-DLBCL based on histopathological biopsy between 2006 and 2023.Patients were stratified into two subgroups:primary OA-DLBCL(no prior history of lymphoma)and secondary OA-DLBCL(history of DLBCL at non-ocular adnexal sites).OS was defined as the time interval from OA-DLBCL diagnosis to death from any cause.Survival analysis was performed using the Kaplan–Meier method,and prognostic factors affecting OS were identified using multivariate Cox proportional hazards regression with a stepwise selection approach.RESULTS:The cohort included 24 patients with primary OA-DLBCL(13 males,11 females;mean age:61.36±18.29y)and 5 patients with secondary OA-DLBCL(2 males,3 females;mean age:50.94±18.17y).Among the primary OA-DLBCL subgroup,12 patients(50%)presented with advanced disease(Ann Arbor stage IIIE–IV),and 16 patients(66%)were classified as T4 disease according to the tumor-node-metastasis(TNM)staging system.The mean final visual acuity was 1.72±1.10 in the primary group and 0.90±1.18 in the secondary group.The 5-year OS rate for the entire cohort was 27.7%.Multivariate analysis identified five factors significantly associated with poor survival outcomes:epiphora[adjusted hazard ratio(aHR),36.95],atherosclerotic cardiovascular disease(aHR,10.08),human immunodeficiency virus(HIV)infection(aHR,12.47),M1 stage(aHR,6.99),and secondary OA-DLBCL(aHR,6.03;all P<0.05).The median OS was 1.68y for primary OA-DLBCL and 1.12y for secondary OA-DLBCL.CONCLUSION:A substantial proportion of patients with primary OA-DLBCL present with advanced-stage disease at diagnosis.Epiphora,atherosclerotic cardiovascular disease,HIV infection,M1 stage,and secondary OA-DLBCL are independent prognostic factors for poor survival outcomes.These findings emphasize the urgent need for optimized therapeutic strategies and early screening protocols to improve the management of OA-DLBCL,particularly in developing countries.
文摘For a long time,forestry primarily had industrial goals.Volume of wood production was the main criterion of forestry efficacy,and thus rapid-growing arboreal species were cultivated in natural forests.More recently,nature protection has become one of forestry＇s goals.Unfortunately,some introduced,rapid-growing species became aggressive components of natural ecological systems during the interim.In this paper,we first describe a method that we developed to categorize aggressiveness of invasive arboreal plants in natural forest ecosystems of Kazakhstan.We then apply this new scheme to monitoring data of invasive arboreal plants to provide an insight into the invasion potential of different species in the fruit forests of Southeast Kazakhstan.
基金The National Natural Science Foundation of China(No.10971025)
文摘A linear forest is a forest whose components are paths. The linear arboricity la （G） of a graph G is the minimum number of linear forests which partition the edge set E（G） of G. The Cartesian product G□H of two graphs G and H is defined as the graph with vertex set V（G□H） = {（u, v）｜ u ∈V（G）, v∈V（H） } and edge set E（G□H） = { （ u, x） （ v, Y）｜u=v and xy∈E（H）, or uv∈E（G） and x=y}. Let Pm and Cm,, respectively, denote the path and cycle on m vertices and K, denote the complete graph on n vertices. It is proved that （Km□Pm）=[n＋1/2]for m≥2,la（Km□Cm）=[n＋2/2],and la（Km□Km）=[n＋m-1/2]. The methods to decompose these graphs into linear forests are given in the proofs. Furthermore, the linear arboricity conjecture is true for these classes of graphs.
基金Sponsored by Forestry Science and Technology Plan of Hunan Province(XLK201806,XLK201925)National Forestry Science and Technology Development Project(KJZXSA2018011,KJZXSA2019009)Operational Subsidy Project of National Forestry Science and Technology Innovation Platform(2019132068)
文摘In this paper, secondary forest of Pinus massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest were taken as research objects, to explore carbon reserve of arbor layer and its spatial distribution characteristics. At different succession stages, the sequence of organic carbon content in each organ was secondary forest of P. massoniana > coniferous-broad-leaved mixed forest> broad-leaved evergreen forest. Carbon reserve of arbor layer was the highest in broad-leaved evergreen forest, which was 129.34 t/hm 2, followed by coniferous-broad-leaved mixed forest (95.83 t/hm 2), and the minimum was 85.27 t/hm 2 in secondary forest of P. massoniana . In each stand type, the sequence of carbon reserve of each organ in arbor layer was trunk>root>branch>leaf>bark. Carbon reserve of arbor layer mainly concentrated in trunk, and the proportion to carbon reserve of arbor layer declined from secondary forest of P. massoniana to broad-leaved evergreen forest, while it had increasing relationship in root. In secondary forest of P. massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest, individual with the diameter more than 20 cm accounted for the majority of carbon reserve in the arbor layer.
基金The work was supported by the Fundamental Research Funds for the Central University(No.2572020DY11).
文摘Pine wilt disease caused by pine wood nema-todes is a deadly disease of the genus Pinus requiring strong quarantine measures.Since its discovery,it has been widely distributed throughout the world.China is one of the coun-tries with a severe rate of infections due to its abundant pine resources.In this study,nematode-trapping fungi were collected from pine trees in Ninghai City,Zhejiang Prov-ince,which is the key area of pine wilt control in Febru-ary,May,September,October and November.The results showed that nematode-trapping fungi of pine are abundant,especially the number and species detected in each month and are quite different;species of fungi in July,Septem-ber and November were more numerous and had higher separation rates.The dominant species in November was Arthrobotrys oligospora followed by Arthrobotrys cladodes;July and September it was A.cladodes.In each part of the tree,A.cladodes was the most widely distributed with a high separation rate.Therefore,it is the dominant fungal species in the area.Arboreal Bursaphelenchus xylophilus-trapping fungi are dependent on pine wood nematodes,and none were isolated from healthy pine trees.More arboreal B.xylophilus-trapping fungi were found under the bark than in the xylem.There is a close relationship between arboreal B.xylophilus-trapping fungi and pine wood nematodes.How to make use of these resources to reduce the damage of pine wood nematode fusarium is the focus of future research.
文摘The seasonality and relative abundance of arboreal ant species were studied in the oil palm plantations of CSIR-OPRI at Kusi in order to identify the different arboreal ant species in the oil palm canopy and their possible interaction with other fauna and flora. Chemical knockdown and field observation and were used in the data collection. Chemical knockdown study was used to collect data on the relative abundance of the ants with application of a synthetic pyrethroid. Field observation was used to study the nesting behaviour, types of nests and where they were built as well as the interaction between the ant species. The fields which were of ages of 8, 11 and 14 years were one hectare containing 143 palms. Chemical knockdown and ant colony studies revealed higher abundance of arboreal ant species on the I 1 years followed by the 8 years and 14 years fields in that order. Oecophylla longinoda was abundant on the I 1-and 14-year-old fields while Crematogaster sp. was the most abundant species on the 8-year old fields. Relatively high numbers of the ant species were encountered in the dry months of study. Positive interaction indicated coexistence between O. longinoda and Crematogaster sp. Interaction between Crematogaster sp. and Tetramorium sp. was antagonistic. Similarly, O. longinoda and Tetramorium sp. were antagonistic to each other. The high abundance and diversity hold promise for the potential use of these ant species as biocontrol agents in an integrated pest management system for the management of the oil palm leaf miner.
基金Sponsored by Forestry Science and Technology Plan of Hunan Province(XLK201925,XLK201806)National Forestry Science and Technology Development Project(KJZXSA2018011)Operational Subsidy Project of National Forestry Science and Technology Innovation Platform(2018-LYPT-DW-064)
文摘In this paper,the Pinus massoniana forest in the early stage of succession,the coniferous broad-leaved mixed forest in the middle stage of succession,and the evergreen broad-leaved forest in the late stage of succession were studied,and the biomass and its spatial distribution characteristics of the tree layer in different succession stages of the ecosystem were discussed.The results showed that the biomass of the arbor layer was the highest in the evergreen broad-leaved forest,which was 292.51 t/hm2,followed by the coniferous and broad-leaved mixed forest,which was 206.87 t/hm2,and the Pinus massoniana forest,which was 171.76 t/hm^(2).The biomass of trunks accounted for the largest proportion in the total biomass of the arbor layer,which reduced from the Pinus massoniana forest to the evergreen broad-leaved forest.The proportion of the biomass of roots in the total biomass of the arbor layer increased from the Pinus massoniana forest to the evergreen broad-leaved forest.The biomass of the diameter class above 20 cm in the Pinus massoniana forest,the coniferous and broad-leaved mixed forest and the evergreen broad-leaved forest accounted for a large proportion of total biomass.
基金National Natural Science Foundation of China(No.10971025)
文摘A star forest is a forest whose components are stars. The star arboricity of a graph G,denoted by sa（ G）,is the minimum number of star forests needed to decompose G. Let k be a positive integer. A k-star forest is a forest whose components are stars of order at most k ＋ 1. The k-star arboricity of a graph G,denoted by sak（ G）,is the minimum number of k-star forests needed to decompose G. In this paper,it is proved that if any two vertices of degree 3 are nonadjacent in a subcubic graph G then sa2（ G） ≤2.For general subcubic graphs G, a polynomial-time algorithm is described to decompose G into three 2-star forests. For a tree T and[Δ k, T）/k]t≤ sak（ T） ≤[Δ（ T）- 1/K]＋1,where Δ（ T） is the maximum degree of T.kMoreover,a linear-time algorithm is designed to determine whether sak（ T） ≤m for any tree T and any positive integers m and k.
