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Influence of Fruit Tree Types and Arrangements on Yield, Quality and Economic Returns of Cotton of Intercropping System in Southern Xinjiang 被引量:2
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作者 林涛 田立文 +3 位作者 郭仁松 汤秋香 崔建平 徐海江 《Agricultural Science & Technology》 CAS 2013年第9期1244-1248,1262,共6页
[Objective] The aim was to provide a theoretical basis for stable and highly effective intercropping arrangements and scientific management measures by selecting apple, pear, peach, apricot, walnut, jujube and other f... [Objective] The aim was to provide a theoretical basis for stable and highly effective intercropping arrangements and scientific management measures by selecting apple, pear, peach, apricot, walnut, jujube and other fruit trees to study their influence on yield, fiber quality and economic returns of intercropped cotton in southern Xinjiang. [Method] Based on major cropping pattern in production, randomized block design was adopted to explore growth indicators, canopy micrometeorological indicators, yield and fiber quality in key growth stage. [Result] Shading has a significant effect on cotton canopy micro-environment and canopy diameter is proportional to shading effect. According to comparisons of the same tree type, the change of canopy micro-environment was as follows: under canopyouter canopymiddle points and peachpearapplewalnutjujube for comparisons among different tree types. Canopy diameter is directly proportional to the number of tree branch and boll weight reductions and shading is the main cause of yield reduction. The canopy expansion is the major cause of decline of light intensity, temperature and humidity of cotton canopy. [Conclusion] Fruit trees, which will promote cotton yield,quality and canopy-environment, are as follows: jujube walnut apple pear peach trees. In practice, trees, which are small in canopy or well trimmed, are popular in production, such as jujube trees, to improve cotton yield and fiber quality. 展开更多
关键词 Intercropping of fruit trees and cottons Fruit tree type Intercropping arrangements COTTON INFLUENCE
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Tree species diversity and stand structure along major community types in lowland primary and secondary moist deciduous forests in Tripura,Northeast India 被引量:4
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作者 Koushik Majumdar Uma Shankar Badal Kumar Datta 《Journal of Forestry Research》 CAS CSCD 2012年第4期553-568,共16页
Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura. Overall 10,957 individual trees belonging ... Tree species diversity and population structure at different community types were described and analyzed for primary and secondary lowland moist deciduous forests in Tripura. Overall 10,957 individual trees belonging to 46 family, 103 genera and 144 species were counted at ≥30 cm DBH (diameter at breast height) using 28 permanent belt transects with a size of 1 ha (10 m × 1000 m). Four different tree communities were identified. The primary forests was dominated by Shorea robusta (mean density 464.77 trees.ha^-1, 105 species) and Schima wallichii (336.25 trees.ha^-1, 82 species), while the secondary forests was dominated by Tectona grandis (333.88 trees.ha^-1, 105 species) and Hevea brasiliensis (299.67 trees.ha^-1, 82 species). Overall mean basal area in this study was 18.01m2.ha^-1; the maximum value was recorded in primary Shorea forest (26.21 m2.ha^-1). Mean density and diversity indices were differed significantly within four different communities. No significant differences were observed in number of species, genera, family and tree basal cover area. Significant relationships were found between the species richness and different tree population groups across the communities. Results revealed that species diversity and density were increased in those forests due to past disturbances which resulted in slow accumu- lation of native oligarchic small tree species. Seventeen species were recorded with 〈2 individuals of which Saraca asoka (Roxb.) de Wilde and Entada phaseoloides (L.) Men'. etc. extensively used in local ethnomedicinal formulations. The present S. robusta Gaertn dominated forest was recorded richer (105 species) than other reported studies. Moraceae was found more speciose family instead of Papilionaceae and Euphorbiaceae than other Indian moist deciduous forests. Seasonal phenological gap in such moist deciduous forests influenced the population of Trachypithecus pileatus and capped langur. The analysis of FIV suggested a slow trend of shifting the population of Lamiaceae group by Moraceae species in secondary T. grandis L. dominated community. 展开更多
关键词 diversity and stand structure moist deciduous forest species conservation tree community types
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Spatial pattern of tree diversity and evenness across forest types in Majella National Park,Italy 被引量:1
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作者 Mohammad Redowan 《Forest Ecosystems》 SCIE CSCD 2015年第4期304-313,共10页
Background: Estimation of tree diversity at broader scale is important for conservation planning. Tree diversity should be measured and understood in terms of diversity and evenness, two integral components to descri... Background: Estimation of tree diversity at broader scale is important for conservation planning. Tree diversity should be measured and understood in terms of diversity and evenness, two integral components to describe the structure of a biological community. Variation of the tree diversity and evenness with elevation, topographic relief, aspect, terrain shape, slope, soil nutrient, solar radiation etc. are well documented. Methods: Present study explores the variation of tree diversity (measured as Shannon diversity and evenness indices) of Majella National Park, italy with five available forest types namely evergreen oak woods, deciduous oak woods, blacWaleppo pine stands, hop-hornbeam forest and beech forest, using satellite, environmental and field data. Results: Hop-hornbeam forest was found to be most diverse and even while evergreen Oak woods was the lowest diverse and even. Diversity and evenness of forest types were concurrent to each other i.e. forest type which was more diverse was also more even. As a broad pattern, majority portion of the study area belonged to medium diversity and high evenness class. Conclusions: Satellite images and other GIS data proved useful tools in monitoring variation of tree diversity and evenness across various forest types. Present study findings may have implications in prioritizing conservation zones of high tree diversity at Majella. 展开更多
关键词 tree diversity tree evenness Forest type Shannon diversity index Shannon evenness index Neural network Kappa statistic
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Studies on Rubber (<i>Hevea brasiliensis</i>) Trees Exist Plant Type after Planting and Available Tapping Tree of Rubber Plantation in China
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作者 Dongling Qi Jiannan Zhou +1 位作者 Guishui Xie Zhixiang Wu 《American Journal of Plant Sciences》 2014年第20期3017-3021,共5页
Existing plant types of rubber tree after planting and available tapping tree were investigated, and there were about 28 rubber plantations with different tapping years of 8 varieties “CATAS7-33-97”, “CATAS8-79”, ... Existing plant types of rubber tree after planting and available tapping tree were investigated, and there were about 28 rubber plantations with different tapping years of 8 varieties “CATAS7-33-97”, “CATAS8-79”, “CATAS7-20-59”, “PR107”, “RRIM600”, “GT1”, “INA873”, “93-114”in South China. The results showed that there were six kinds of existing plant types of rubber tree after planting of rubber plantations, which were available tapping trees, wind damaged trees, cold damaged trees, tapping panel dryness trees, absent trees and weak trees, respectively. These data investigated also showed rubber trees under available tapping, stoppage due to tapping panel dryness, absence, wind damage, cold damage and weakness were counted and calculated and made up for 72.21%, 14.75%, 5.61%, 3.86%, 2.68% and 1.89%. Tapping panel dryness trees, wind damage and absent trees are major factors for the loss of tapping rubber trees in the rubber plantations. Of these investigated varieties, available tapping trees per 100 trees of rubber plantation of “PR107”at the 1st, 12th, 14th, 16th, 20th, 24th tapping year were 96, 67, 70, 75, 66, 46 trees in Hainan planting zone, respectively. Available tapping trees per 100 trees of rubber plantation of “RRIM600”at the 9th, 15th, 20th, 22nd tapping year were 88, 62, 55, 36 trees in Yunnan planting zone, respectively. Available tapping trees per 100 trees of rubber plantation of “93-114” at the 10th, 19th, tapping year were 94, 62 trees in Guangdong planting zone. These results showed that available tapping trees of rubber plantation decreased with increasing tapping age under different planting zones in China. 展开更多
关键词 RUBBER tree (Hevea brasiliensis) Exist Plant type Available TAPPING tree RUBBER Plantations Different TAPPING Years China
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Biliary tree gastrinomas in multiple endocrine neoplasia type 1 syndrome 被引量:3
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作者 Francesco Tonelli Francesco Giudici +2 位作者 Gabriella Nesi Giacomo Batignani Maria Luisa Brandi 《World Journal of Gastroenterology》 SCIE CAS 2013年第45期8312-8320,共9页
AIM:To describe our patients affected with ectopic biliary tree gastrinoma and review the literature on this topic.METHODS:Between January 1992 and June 2012,28 patients affected by duodenopancreatic endocrine tumors ... AIM:To describe our patients affected with ectopic biliary tree gastrinoma and review the literature on this topic.METHODS:Between January 1992 and June 2012,28 patients affected by duodenopancreatic endocrine tumors in multiple endocrine neoplasia type 1(MEN1)syndrome underwent surgery at our institution.This retrospective review article analyzes our experience regarding seventeen of these patients subjected to duodenopancreatic surgery for Zollinger-Ellison syndrome(ZES).Surgical treatment consisted of duodenopancreatectomy(DP)or total pancreatectomy(TP).Regional lymphadenectomy was always performed.Any hepatic tumoral lesions found were removed during surgery.In MEN1 patients,removal of duodenal lesions can sometimes lead to persistence or recurrence of hypergastrinemia.One possible explanation for this unfavorable outcome could be unrecognized ectopic localization of gastrin-secreting tumors.This study described three cases among the seventeen patients who were found to have an ectopic gastrinoma located in the biliary tree.RESULTS:Seventeen MEN1 patients affected with ZES were analyzed.The mean age was 40 years.Fifteen patients underwent DP and two TP.On histopathological examination,duodeno pancreatic endocrine tumors were found in all 17 patients.Eighty-one gastrinomas were detected in the first three portions of the duodenum.Only one gastrinoma was found in the pancreas.The mean number of gastrinomas per patient was 5(range 1-16).Malignancy was established in 12 patients(70.5%)after lymph node,liver and omental metastases were found.Three patients exhibited biliary tree gastrinomas as well as duodenal gastrinoma(s).In two cases,the ectopic gastrinoma was removed at the same time as pancreatic surgery,while in the third case,the biliary tree gastrinoma was resected one year after DP because of recurrence of ZES.CONCLUSION:These findings suggest the importance of checking for the presence of ectopic gastrinomas in the biliary tree in MEN1 patients undergoing ZES surgery. 展开更多
关键词 GASTRINOMA Multiple endocrine NEOPLASIA type 1 Zollinger-Ellison SYNDROME Ectopic GASTRINOMA Biliary tree DUODENOPANCREATECTOMY
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Artin Transfer Patterns on Descendant Trees of Finite p-Groups 被引量:3
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作者 Daniel C. Mayer 《Advances in Pure Mathematics》 2016年第2期66-104,共39页
Based on a thorough theory of the Artin transfer homomorphism from a group G to the abelianization of a subgroup of finite index , and its connection with the permutation representation and the monomial representation... Based on a thorough theory of the Artin transfer homomorphism from a group G to the abelianization of a subgroup of finite index , and its connection with the permutation representation and the monomial representation of G, the Artin pattern , which consists of families , resp. , of transfer targets, resp. transfer kernels, is defined for the vertices of any descendant tree T of finite p-groups. It is endowed with partial order relations and , which are compatible with the parent-descendant relation of the edges of the tree  T. The partial order enables termination criteria for the p-group generation algorithm which can be used for searching and identifying a finite p-group G, whose Artin pattern is known completely or at least partially, by constructing the descendant tree with the abelianization of G as its root. An appendix summarizes details concerning induced homomorphisms between quotient groups, which play a crucial role in establishing the natural partial order on Artin patterns and explaining the stabilization, resp. polarization, of their components in descendant trees T of finite p-groups. 展开更多
关键词 Artin Transfer Kernel type Target type Descendant tree Coclass tree Coclass Graph
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Tree Automaton Based Algorithms for Sub-Typing and inDOM Relations in XQuery
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作者 XIERong-chuan XIEXuan-yang 《Wuhan University Journal of Natural Sciences》 EI CAS 2004年第5期652-658,共7页
Proposed by W3C (World Wide Web Consortium), XQuery is a descriptive query language for XML structured data or documents. The specification of XQuery gives functional description of XQuery’s typing system, but doestn... Proposed by W3C (World Wide Web Consortium), XQuery is a descriptive query language for XML structured data or documents. The specification of XQuery gives functional description of XQuery’s typing system, but doestn’t provide methods to judge the Sub-typing and inDOM relations in language compiling. In this paper, both of the two important relations: Sub-typing and inDOM, are described and analyzed. After some definitions of Tree Automaton, the judgment algorithms of these two relations are proposed. Key words XQuery - typing system - tree automata CLC number TP 301. 6 Biography: XIE Rong-chuan (1946-), male, Associate professor, research direction: database, internet information system. 展开更多
关键词 XQUERY typing system tree automata
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Tree species as hosts for arbuscular mycorrhizal and dark septate endophyte fungi 被引量:3
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作者 E.Uma K.Sathiyadash +1 位作者 J.Loganathan T.Muthukumar 《Journal of Forestry Research》 CAS CSCD 2012年第4期641-649,共9页
A survey of 35 tree species (belonging to 28 genera in 19 families) in Aliyar, South India was carried out to ascertain their arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal status. All the t... A survey of 35 tree species (belonging to 28 genera in 19 families) in Aliyar, South India was carried out to ascertain their arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal status. All the tree species examined had AM association. AM and DSE coloni- zation is reported for the first time in 20 and 14 species respectively. Co- occurrence of AM and DSE was observed in 14 (40%) tree species. The extent of DSE colonization was inversely related to the extent of AM fungal colonization. Six tree species had Arum-type, 18 had intermediate- type and 11 had typical Paris-type AM morphology. AM fungal spore morphotypes belonging to 11 species in two genera were isolated from the rhizosphere soil. AM fungal spore numbers were not related to the ex- tent of AM colonization and Glomus dominated spore diversity. AM association individually and along with DSE were found respectively in the 63% and 44% of the economically important tree species. The occur- rence of AM and DSE fungal association in economically important indigenous tree species indicates the possibility of exploiting this asso- ciation in future conservation programmes of these species. 展开更多
关键词 tree species AM fungi Arum- Paris- intermediate- type dark septate endophyte (DSE)
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Response of species and stand types to snow/wind damage in a temperate secondary forest,Northeast China 被引量:1
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作者 Xiufen Li Lei Jin +4 位作者 Jiaojun Zhu Limin Liu Jinxin Zhang Yi Wang Chengyao Zhu 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第2期390-399,共10页
Snow/wind damage is one of the important natural disturbances in forest ecosystems,especially in a montane secondary forest.However,the effects of snow/wind damage remain unclear which affects the management of these ... Snow/wind damage is one of the important natural disturbances in forest ecosystems,especially in a montane secondary forest.However,the effects of snow/wind damage remain unclear which affects the management of these forests.Therefore,we investigated the responses of species,individual tree traits and stand structure to snow/wind damage in a montane secondary forest.Results show that,amongst the canopy trees,Betula costata exhibited the most uprooting,bending and overall damage ratio(the number of damaged stems to the total number of stems in a plot); Quercus mongolica showed the highest breakage ratio and Fraxinus mandshurica and Juglans mandshurica the least overall damage ratios.Among the subcanopy trees,Carpinus cordata,Acer mono,Acer tegmentosum and Acer pseudo-sieboldianum showed the least uprooting and breakage,and the most bending damage.A.pseudo-sieboldianum demonstrated the lowest breakage and highest bending damage ratios.Thesefindings indicate that different species have various sensitivities to snow/wind damage.Larger trees(taller,wider crowns) tend to break and become uprooted,while smaller trees are bent or remain undamaged,suggesting that tree characteristics significantly influence the types of damage from snow and wind.Stands of Q.mongolica and B.costata had the highest damage ratios,whereas A.pseudosieboldianum had the lowest snapping ratio.In summary,the severity and type of snow/wind damage are related to individual tree attributes and stand-level characteristics.Therefore,selection of suitable species(e.g.,shorter,smaller with deep root systems,hard wood,bending resistance and compression resistance) and appropriate thinning are recommended for planting in the montane secondary forests. 展开更多
关键词 Cover type Montane secondary forests Storm damage tree species
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河西走廊酿酒葡萄老园改优技术规程 被引量:1
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作者 郝燕 朱燕芳 +1 位作者 张露荷 陈海龙 《寒旱农业科学》 2025年第5期478-481,共4页
河西走廊气候干燥少雨,热量充足,是我国酿酒葡萄适宜生产区域,拥有莫高、紫轩、祁连、国风等多家知名葡萄酒品牌。河西酿酒葡萄经过二十多年的发展历程,葡萄老园出现产量低、品质退化、经济效益低下等问题。为提高酿酒葡萄原料品质,提... 河西走廊气候干燥少雨,热量充足,是我国酿酒葡萄适宜生产区域,拥有莫高、紫轩、祁连、国风等多家知名葡萄酒品牌。河西酿酒葡萄经过二十多年的发展历程,葡萄老园出现产量低、品质退化、经济效益低下等问题。为提高酿酒葡萄原料品质,提升葡萄园经济效益,经过多年的试验研究和生产示范,从适用范围、规范性引用文件、术语及定义、改优对象、改优技术、冬季埋土防寒等方面规范了河西走廊酿酒葡萄老园改优技术体系,主要包括品种更换、嫁接改良、株距调整、架式改优、树形改良、整形修剪、土壤改良、病虫害绿色防控技术等,对指导河西走廊酿酒葡萄老园改优和提质增效、提高甘肃河西走廊葡萄酒产业高质量发展具有重要意义。 展开更多
关键词 河西走廊 酿酒葡萄 改优技术 架式改优 树形改良
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星型k-树的(度)基尔霍夫指标和生成树的数目
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作者 曹月芬 杨维玲 《厦门大学学报(自然科学版)》 北大核心 2025年第4期703-708,共6页
[目的]近年来,图的电阻距离得到了国内外研究学者的广泛关注和深入研究,但是对k-树的电阻距离研究较少,本文主要研究星型k-树的电阻距离、(度)基尔霍夫指标和生成树的数目.[方法]本文用串并联法则和星-三角变换以及推广的星-网格变换等... [目的]近年来,图的电阻距离得到了国内外研究学者的广泛关注和深入研究,但是对k-树的电阻距离研究较少,本文主要研究星型k-树的电阻距离、(度)基尔霍夫指标和生成树的数目.[方法]本文用串并联法则和星-三角变换以及推广的星-网格变换等方法来计算星型k-树的电阻距离和生成树的数目.[结果]设G是连通图,G中任意两点之间的电阻距离定义为将G中的每条边用电阻(通常用单位电阻)代替后所得到的电网络中这两个节点之间的等效电阻.连通图G的基尔霍夫指标Kf(G)定义为图G中所有点对之间的电阻距离之和.本文得出了星型k-树的(度)基尔霍夫指标和生成树的数目.[结论]生成树的数目经常用谱的方法来计算,本文用推广的星-网格变换的方法得出生成树的数目,这给出了一个新的思路. 展开更多
关键词 电阻距离 基尔霍夫指标 度基尔霍夫指标 星型k-树
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基于两级决策树模型的轧制时间预测方法 被引量:2
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作者 张卓伦 袁帅鹏 +1 位作者 李铁克 张文新 《计算机集成制造系统》 北大核心 2025年第1期197-210,共14页
轧制时间是宽厚板热轧生产的关键参数,但由于生产的复杂性和不确定性,在生产准备阶段很难对其进行精准预设,这会影响生产作业计划的编制以及实施效果。为解决这一问题,着眼于生产中积累的大量宽厚板轧制历史数据,在对影响轧制时间的关... 轧制时间是宽厚板热轧生产的关键参数,但由于生产的复杂性和不确定性,在生产准备阶段很难对其进行精准预设,这会影响生产作业计划的编制以及实施效果。为解决这一问题,着眼于生产中积累的大量宽厚板轧制历史数据,在对影响轧制时间的关键因素及相互关系进行分析梳理的基础上,针对其数据类型和数据结构的特点,提出了两级决策树预测模型,以提高轧制时间的预设精度。首先,基于属性间依赖关系改进C4.5的信息增益率,利用信息熵水平约简分枝节点,将改进的C4.5分类树用于数据中标称属性的建模;进而,基于Fayyad边界点判定定理和支持向量机改进CART算法,对分类子集中数值型属性建立回归模型。从轧制历史数据中随机抽取样本进行实验,将两级决策树模型与多种预测模型对比,验证了所提模型的准确性和鲁棒性。 展开更多
关键词 轧制时间 C4.5方法 两级决策树 混合类型数据 属性依赖
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鄂尔多斯高原水土保持林碳密度分配格局及其影响因素
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作者 周艾荣 王树森 +3 位作者 张平 杨振奇 铁露 刘世凡 《水土保持研究》 北大核心 2025年第6期169-176,共8页
[目的]探究鄂尔多斯高原水土保持林碳密度及其分布规律,为该地区水土保持林碳汇经营管理与科学规划提供依据。[方法]以鄂尔多斯市水土保持林山杏(Prunus sibirica)林、油松(Pinus tabulaeformis)林和山杏-油松混交林为研究对象,通过野... [目的]探究鄂尔多斯高原水土保持林碳密度及其分布规律,为该地区水土保持林碳汇经营管理与科学规划提供依据。[方法]以鄂尔多斯市水土保持林山杏(Prunus sibirica)林、油松(Pinus tabulaeformis)林和山杏-油松混交林为研究对象,通过野外调查与试验相结合的方法,综合探究不同水土保持林生态系统碳密度分布特征及其影响因素。[结果](1) 3种水土保持林生态系统碳密度依次为山杏林(60.99 t/hm^(2))>油松林(47.09 t/hm^(2))>山杏-油松混交林(44.30 t/hm^(2))>撂荒地(27.43 t/hm^(2)),较撂荒地分别增加122.33%,71.64%和61.47%(p<0.05)。(2) 3种水土保持林生态系统各组分碳密度依次为土壤层>乔木层>凋落物层>草本层,土壤层碳密度所占比例最高,占生态系统碳密度的92.64%~94.59%。(3) 3种水土保持林乔木层各组分碳密度依次为树干>根系>枝条>叶。其中,树干和根系分别占整个乔木层的40.41%~60.61%和26.04%~37.74%。(4)相关关系分析发现,生态系统、乔木层、草本层和土壤层碳密度均与土壤含水量(SWC)、氨态氮(AN)极显著正相关(p<0.01),与pH和硝态氮(NN)显著负相关(p<0.05)。(5)冗余分析发现,氨态氮(AN)、硝态氮(NN)、全氮(TN)、速效磷(AP)和速效钾(AK)是影响水土保持林碳密度的关键因子。[结论]在营造水土保持林的过程中,选择山杏更有利于生态系统有机碳固存和积累,并在造林过程中需要对水土保持林施加氮肥。 展开更多
关键词 碳密度 空间分配格局 树种类型 水土保持林 鄂尔多斯高原
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不同花型牡丹成花过程中表型及理化指标动态变化
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作者 王朵朵 魏冬峰 +5 位作者 郭琪 李昱莹 杨雪婷 牛童非 张楠楠 侯小改 《林业科学》 北大核心 2025年第10期26-37,共12页
【目的】探究不同花型牡丹成花过程中表型及理化指标动态变化,为牡丹成花品质的提升及花型改良提供理论依据。【方法】以单瓣型品种‘凤丹’和菊花型品种‘连鹤’成花过程中13个不同发育阶段的花芽(朵)为试验材料,采用形态结构观测和植... 【目的】探究不同花型牡丹成花过程中表型及理化指标动态变化,为牡丹成花品质的提升及花型改良提供理论依据。【方法】以单瓣型品种‘凤丹’和菊花型品种‘连鹤’成花过程中13个不同发育阶段的花芽(朵)为试验材料,采用形态结构观测和植物生理学测定方法,分析不同花型牡丹成花过程中的外部形态和相关重要生理生化指标[吲哚乙酸(IAA)、脱落酸(ABA)、玉米素核苷(ZR)、赤霉素(GA_(3))、可溶性糖、可溶性蛋白、超氧化物歧化酶(SOD)、过氧化物酶(POD)]的动态变化情况。【结果】‘凤丹’和‘连鹤’的花芽(朵)自越冬鳞芽期至盛开期在宽度和高度上均呈不同程度增长,二者分别在大风铃期和小风铃期开始快速增长,且均在盛开期达到峰值。从初开期到盛开期,‘凤丹’的ZR含量升高,‘连鹤’的ZR含量持续下降。‘凤丹’和‘连鹤’的可溶性糖和可溶性蛋白含量变化趋势一致,但‘凤丹’的可溶性糖和可溶性蛋白含量从平桃期起始终高于‘连鹤’。‘凤丹’和‘连鹤’在破绽期的SOD活性相较于前一阶段均表现出增长趋势,随着发育继续进行,‘凤丹’的SOD活性呈先升高后降低的趋势,‘连鹤’的SOD活性则呈先降低后升高的趋势。‘凤丹’和‘连鹤’不同发育阶段花芽(朵)中的POD活性变化趋势基本一致,但在变动幅度上略有差异。【结论】大风铃期至盛开期为‘凤丹’的快速生长期,小风铃期至盛开期为‘连鹤’的快速生长期。高含量的IAA和低含量的ABA、GA_(3)可促进‘凤丹’和‘连鹤’花朵绽放,高水平的ABA/IAA、ABA/GA_(3)和低水平的ZR/IAA、ZR/GA_(3)可能更有利于牡丹花芽打破休眠,萌动膨大期和圆桃期各种激素波动程度较大。‘凤丹’和‘连鹤’花芽中营养物质含量、抗氧化酶活性最高的阶段为萌动膨大期。小风铃期是不同品种牡丹向不同花型进行差异分化的关键阶段。 展开更多
关键词 牡丹 花型 内源激素 营养物质 抗氧化酶
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GADA检测在成人隐匿性自身免疫性糖尿病诊断中的临床应用研究
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作者 王瑶 滕凤猛 +1 位作者 安晓飞 詹晓燕 《中国医药科学》 2025年第9期154-159,共6页
目的研究初诊2型糖尿病(T2DM)患者群体中,成人隐匿性自身免疫糖尿病(LADA)的检出率及谷氨酸脱羧酶抗体(GADA)在鉴别LADA和T2DM临床应用中的价值。方法选取2022年1月至2024年1月江苏省中医院检验科收集的113例初诊T2DM患者为研究对象,检... 目的研究初诊2型糖尿病(T2DM)患者群体中,成人隐匿性自身免疫糖尿病(LADA)的检出率及谷氨酸脱羧酶抗体(GADA)在鉴别LADA和T2DM临床应用中的价值。方法选取2022年1月至2024年1月江苏省中医院检验科收集的113例初诊T2DM患者为研究对象,检测其血清中的GADA,根据诊疗标准将患者划分为LADA组和T2DM组,并对这两组进行临床资料和生化检测结果的对比研究。为了评价相关指标在区分LADA和T2DM的诊断价值,绘制受试者工作特征(ROC)曲线;运用决策树机器学习模型,进一步评价指标并区分LADA和T2DM的效果,在训练后初步预测诊断。结果初诊为T2DM患者中GADA>10 IU/ml的患者中,GADA在区分LADA和T2DM患者方面具有非常好的区分度,AUC值高达0.801;空腹C肽(CP)在区分LADA和T2DM患者方面具有较好的区分度,AUC值为0.651;糖化血红蛋白(HbA1c)在区分LADA和T2DM患者方面的区分度有限,AUC值为0.374,但仍具有一定的统计学意义。决策树模型不仅验证了描述性、相关性和ROC曲线分析的结论,且在少样本的条件下,利用GADA、CP和HbA1c指标实现诊断预测精度达0.760。结论对初诊为T2DM的患者进行GADA检测是筛查LADA的重要指标,而CP和HbA1c作为次要指标,有助于提高LADA的诊断准确性。本研究的结果支持在临床实践中应用GADA检测,并结合决策树模型辅助诊断LADA,为LADA早期诊断和治疗提供了新的工具。 展开更多
关键词 谷氨酸脱羧酶抗体 成人隐匿性自身免疫糖尿病 2型糖尿病 决策树模型 鉴别诊断
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基于人工合成样本和随机森林回归模型的长时序中国寒温带森林类型和树种覆盖度反演 被引量:1
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作者 王梦雨 赵峰 +3 位作者 庞勇 孟冉 荚文 岳超 《遥感学报》 北大核心 2025年第1期118-133,共16页
寒温带森林是陆地上分布面积最广的森林生态系统,具有重要的生态和社会经济价值。定量描述长时序寒温带森林类型和树种覆盖信息对于量化其生态系统服务功能以及制定森林管理政策具有重要意义。然而受实测覆盖度数据缺乏和多光谱影像光... 寒温带森林是陆地上分布面积最广的森林生态系统,具有重要的生态和社会经济价值。定量描述长时序寒温带森林类型和树种覆盖信息对于量化其生态系统服务功能以及制定森林管理政策具有重要意义。然而受实测覆盖度数据缺乏和多光谱影像光谱信息有限的限制,现有研究较少探究中分辨率多光谱星载数据(如Landsat卫星)对中国寒温带森林类型覆盖度和树种覆盖度进行长时序反演的可行性,并且对于遥感影像获取时间频率(单时相、多时相)对反演精度的影响仍缺乏定量评估。为此,本研究利用人工合成样本和随机森林回归模型对黑龙江省孟家岗林场的森林类型和树种覆盖度分别进行了反演,并将模型应用于1986年—2020年的Landsat影像,估算孟家岗林场阔叶林和针叶林35年的覆盖度。结果表明:(1)对于森林类型覆盖度反演,基于生长季Landsat波段和植被指数(归一化耕作指数以及缨帽变换系数)的中值特征估算的精度最高,阔叶林覆盖度估算R^(2)=0.76,针叶林覆盖度估算R^(2)=0.71;(2)对于树种覆盖度反演,基于多时相Landsat波段和植被指数的精度最高,落叶松覆盖度估算R^(2)=0.40,红松覆盖度估算R^(2)=0.23,樟子松覆盖度估算R^(2)=0.61;(3)增加影像获取时间密度对于森林类型覆盖度反演精度的提高没有显著贡献(阔叶林ΔR^(2)=0.01,针叶林ΔR^(2)=-0.03),但对提高树种覆盖度的反演精度帮助较大(落叶松ΔR^(2)=0.04,红松ΔR^(2)=0.07,樟子松ΔR^(2)=0.27)。本研究可为中国北方森林以及全球寒温带森林类型和树种覆盖度的大尺度长时序估算提供了思路。 展开更多
关键词 遥感 森林类型覆盖度 树种覆盖度 人工合成样本 长时间序列 机器学习
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南亚热带人工林树种配置对土壤有机碳含量和稳定性的影响
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作者 叶晓丹 王晖 +2 位作者 栾军伟 王一 刘世荣 《生态学报》 北大核心 2025年第22期11331-11343,共13页
通过人工造林促进碳封存已成为应对气候变化的一种有效策略。然而,不同树种配置模式如何影响土壤有机碳(SOC)积累和稳定性尚不清楚。以中国南亚热带地区不同树种组成及多样性(1,2,4,6个树种梯度)组配的人工林生态系统为研究对象,系统探... 通过人工造林促进碳封存已成为应对气候变化的一种有效策略。然而,不同树种配置模式如何影响土壤有机碳(SOC)积累和稳定性尚不清楚。以中国南亚热带地区不同树种组成及多样性(1,2,4,6个树种梯度)组配的人工林生态系统为研究对象,系统探究了树种丰富度和功能类型对SOC含量和稳定性的影响。结果表明,土壤易氧化有机碳(EOC)含量、SOC含量和EOC/SOC比值在不同树种丰富度梯度下均未呈现显著差异,但其主要受到树种及其功能类型的显著影响。具体而言,针叶纯林SOC含量显著低于阔叶纯林,针阔混交林SOC含量显著高于针叶纯林和阔叶纯林。针叶纯林、阔叶纯林、针阔混交林和阔阔混交林间土壤EOC含量无显著差异,但林分中存在固氮树种时会显著降低土壤EOC含量。此外,马尾松纯林的EOC/SOC比值显著高于其他林分,而混交林中存在固氮树种时EOC/SOC比值显著降低。结构方程模型结果进一步表明SOC含量主要受树种混交和土壤总氮的直接影响,树种丰富度则通过促进细根生物量和细根氮输入量对SOC含量产生积极影响。EOC/SOC比值主要受固氮树种、真菌/细菌丰度比值和土壤氮有效性的直接影响,树种丰富度主要通过增加细根生物量和真菌/细菌丰度比值进而对EOC/SOC比值产生间接效应。结果表明在纯林尤其是马尾松等针叶纯林中引入固氮树种混交能显著提高SOC含量及其稳定性。研究结果为南亚热带地区科学选择造林树种优化林分配置以提高人工林长期土壤碳封存能力提供了理论依据。 展开更多
关键词 南亚热带 树种丰富度 功能类型 土壤有机碳 稳定性
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不同森林类型树高空间分布特征及影响因素
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作者 潘子阳 崔哲霖 +1 位作者 徐雁南 孙心雨 《东北林业大学学报》 北大核心 2025年第5期31-40,152,共11页
树高是森林资源调查中反应森林生长状况的重要因子,也是林木资产评估、生物量计算和生态服务功能评价的关键指标。以安徽省黄山区的Sentinel-2时序影像为数据源,使用SG滤波后提取的统计特征,结合随机森林与交叉验证特征递归消除方法(RFE... 树高是森林资源调查中反应森林生长状况的重要因子,也是林木资产评估、生物量计算和生态服务功能评价的关键指标。以安徽省黄山区的Sentinel-2时序影像为数据源,使用SG滤波后提取的统计特征,结合随机森林与交叉验证特征递归消除方法(RFECV),获取黄山区森林类型分类栅格;结合机载激光雷达数据提取的树高栅格,分析各森林类型的空间分布特征;利用提取的地形参数和森林结构参数,通过广义加性模型(GAM)分析常见地形参数和冠层参数对树高的影响。结果表明:(1)根据时序统计特征,随机森林模型对森林类型分类总体精度为0.91,Kappa系数为0.89。(2)各森林类型树高的空间自相关性均随距离增加而显著减弱,研究区竹林树高低值主要聚集在西北方,针叶林分布稀疏未呈现聚集现象,阔叶林为研究区的主要森林类型,其树高高值沿东北-西南方向集中分布。(3)在广义加性模型(GAM)中,点云偏态和冠层孔隙率在各森林类型占据较高的相对重要性,坡度、坡向和高程的相对重要性之和不超过40%,冠层孔隙率和平均曲率在多数森林类型中与树高呈显著线性相关关系。 展开更多
关键词 森林类型 树高分布 机载激光雷达 机器学习模型
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猪圆环病毒4型在犬肾脏的检出及Rep基因序列分析 被引量:1
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作者 胡颖 雷祖建 +4 位作者 聂江江 曾庆华 王珂 邬向东 吴欢生 《动物医学进展》 北大核心 2025年第2期42-46,共5页
猪圆环病毒4型(PCV4)于2019年首次在我国湖南省发现,之后在我国河南、山西、广西等地发现猪源PCV4。为了确定PCV4能否感染犬,试验采集江西省南昌市85份死亡犬肾脏,提取总DNA后经PCV4荧光定量PCR(qPCR)检测。结果显示,13份肾脏组织样品呈... 猪圆环病毒4型(PCV4)于2019年首次在我国湖南省发现,之后在我国河南、山西、广西等地发现猪源PCV4。为了确定PCV4能否感染犬,试验采集江西省南昌市85份死亡犬肾脏,提取总DNA后经PCV4荧光定量PCR(qPCR)检测。结果显示,13份肾脏组织样品呈PCV4阳性(Ct值<39),阳性率为15.29%;对阳性样品采用普通PCR扩增,其中有3份扩增出890 bp的特异性Rep条带并测序,将获得的基因序列与GenBank其他圆环病毒的相应基因进行相似性分析及遗传演化分析,结果3条犬源PCV4 Rep基因氨基酸序列相似性为99.4%~99.5%,与湖南分离株(HNU-AHG1-2019)、河南分离株(Henan-LY1-2019)相似性分别为99.6%~99.7%和98.2%~98.7%,与PCV1、PCV2、PCV3相似性均低于50%,与蝙蝠圆环病毒(BatAcV)相似性为60.7%~63.9%,与犬圆环病毒(CaCV)相似性为60.6%~61.3%,进化树显示这3条PCV4 Rep基因序列与猪源PCV4相应基因处于同一进化分支。首次确认我国存在犬感染PCV4的情况,为PCV4流行病学调查及犬圆环类病毒感染研究提供了基础数据。 展开更多
关键词 猪圆环病毒4型 qPCR检测 相似性 进化树
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基于故障树的LZB型全自动立式压滤机液压系统故障诊断专家系统 被引量:1
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作者 崔璐 杨栩卿 +5 位作者 罗涛 郭西贤 李皓源 姚尧 王沛 段佩侠 《机床与液压》 北大核心 2025年第8期203-211,共9页
针对西安某公司生产的LZB型全自动立式压滤机液压系统故障诊断中存在的过度依赖人工经验、诊断效率低及准确性低等问题,提出一种基于故障树和专家系统理论的智能诊断方法。通过引入故障树和专家系统等技术,实现对液压系统故障的分析和... 针对西安某公司生产的LZB型全自动立式压滤机液压系统故障诊断中存在的过度依赖人工经验、诊断效率低及准确性低等问题,提出一种基于故障树和专家系统理论的智能诊断方法。通过引入故障树和专家系统等技术,实现对液压系统故障的分析和智能诊断。基于作业时液压系统出现的各类故障事件建立全自动立式压滤机液压系统的故障树模型,采用层次分析法和聚合模糊数对故障树模型进行分析。根据分析结果以及液压系统的故障信息,选取产生式规则作为知识表示并在SQL Server软件中建立故障诊断知识库,选用基于规则的正向推理和冲突抵消策略作为推理机,构建LZB型全自动立式压滤机液压系统智能故障诊断专家系统。经过适用性验证,该系统可实现故障智能定位、排故建议推送,显著提升了故障处理效率并降低了维修成本。其知识维护等功能确保了系统的持续学习能力,进一步提高了专家系统的故障诊断效率和适用范围,验证了故障树和专家系统融合诊断技术的准确性和可行性。 展开更多
关键词 LZB型全自动立式压滤机 液压系统 故障树 聚合模糊数 专家系统
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