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DIURNAL VARIATION OF SST IN RELATION TO SEASON AND WEATHER PHENOMENA IN THE BOHAI REGION
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作者 王炜 王彦 +2 位作者 曲平 刘丽丽 王钦良 《热带气象学报:英文版》 SCIE 2019年第3期399-413,共15页
This study investigated the relationships between sea surface temperature(SST) and weather phenomena in different seasons in the Bohai region(China). Five categories of weather phenomena were screened(i.e., fine, clou... This study investigated the relationships between sea surface temperature(SST) and weather phenomena in different seasons in the Bohai region(China). Five categories of weather phenomena were screened(i.e., fine, cloudy,foggy, rainy and windy conditions) and their relationships with the difference between air temperature and SST observed at Oil Platform A during 2003-2010 were analyzed statistically. The effects of the difference between air temperature and SST in different weather phenomena were examined using the flux method of the atmospheric boundary layer and a formula for the difference between air temperature and SST. The results revealed diurnal variation of the difference between air temperature and SST of-1.0 to +1.0 ℃, i.e., air temperature above the sea surface is subtracted from the SST in corresponding weather phenomena in different seasons in the Bohai region. Moreover,according to the formula for the difference between air temperature and SST, wind and shortwave radiation are the most important factors in terms of the effects of SST on weather processes. In conclusion, the effects of SST on weather phenomena are manifest via the exchange of momentum and energy from sea to air. When the air temperature above the sea surface is lower than the SST, the SST helps develop mesoscale convection systems within the synoptic system through moisture and sensible heat fluxes. When the air temperature above the sea surface is greater than the SST,synoptic systems transfer energy into the sea through heat flux, which affects SST variation. Moreover, a mesoscale convection system will weaken if the synoptic system passes over a colder underlying surface. 展开更多
关键词 sea surface temperature DIURNAL VARIATION weather phenomena SEASONAL VARIATION heat flux
Environmental contribution to needle variation among natural populations of Pinus tabuliformis 预览
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作者 Jingxiang Meng Xinyu Chen +3 位作者 Yujie Huang Liming Wang Fangqian Xing Yue Li 《林业研究:英文版》 CAS CSCD 2019年第4期1311-1322,共12页
Variations in the phenotypic characteristics of conifer needles is a consequence of genetic evolution that has been widely used in geographic variation and ecological studies.Although many studies are based on an in s... Variations in the phenotypic characteristics of conifer needles is a consequence of genetic evolution that has been widely used in geographic variation and ecological studies.Although many studies are based on an in situ sampling strategy and generally realize the contribution of environmental effects to variation in needle traits,it is still uncertain which needle traits are most influenced by genetic effects and which are most influenced by the environment.Using both a common garden experiment to eliminate environmental heterogeneity and an in situ sampling strategy,we compared 18 Pinus tabuliformis needle traits among 10 geographical populations.Using both sampling strategies,we found significant differences in needle traits among populations and among individuals within populations.Differences in the‘‘among-population’’variance component between the two sampling strategies revealed the environmental contribution among natural populations for each trait.The among-population variance in the following traits exceeded 8%:needle length,number of stomata within 2 mm(NS2),number of stomatal lines on the planar side,number of resin canals(RCN)and the resin canal area(RCA).For the stability of needle traits,NS2,RCN,RCA,ratio of the vascular bundle area to the RCA(VBA/RCA),and MA/RCA differed significantly in more than five provenance changes between the common garden populations and natural populations,which may be susceptible to environmental effects.Conversely,the crosssectional area,mesophyll area(MA),MA/(VBA+RCA),and MA/VBA were phenotypically stable.Geographic variation patterns and systematic relation of needle traits differed between the two sampling strategies,suggesting that in situ sampling results may reflect environmental effects and deviate statistical parameters for genetic study.Future studies of genetic evolution in the context of geographic variation should be based on appropriate sampling strategies and stable phenotypic traits. 展开更多
关键词 ENVIRONMENTAL effect Genetic VARIATION GEOGRAPHICAL VARIATION In SITU sampling NEEDLE traits PINUS tabuliformis
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The role of genomic structural variation in the genetic improvement of polyploid crops 预览
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作者 Sarah-Veronica Schiessl Elvis Katche +2 位作者 Elizabeth Ihien Harmeet Singh Chawla Annaliese S. Mason 《作物学报:英文版》 CAS CSCD 2019年第2期127-140,共14页
Many of our major crop species are polyploids,containing more than one genome or set of chromosomes.Polyploid crops present unique challenges,including difficulties in genome assembly,in discriminating between multipl... Many of our major crop species are polyploids,containing more than one genome or set of chromosomes.Polyploid crops present unique challenges,including difficulties in genome assembly,in discriminating between multiple gene and sequence copies,and in genetic mapping,hindering use of genomic data for genetics and breeding.Polyploid genomes may also bemore prone to containing structural variation,such as loss of gene copies or sequences (presence–absence variation) and the presence of genes or sequences inmultiple copies (copynumber variation).Although the two main types of genomic structural variation commonly identified are presence–absence variation and copy-number variation,we propose that homeologous exchanges constitute a third major form of genomic structural variation in polyploids.Homeologous exchanges involve the replacement of one genomic segment by a similar copy from another genome or ancestrally duplicated region,and are known to be extremely common in polyploids.Detecting all kinds of genomic structural variation is challenging,but recent advances such as optical mapping and long-read sequencing offer potential strategies to help identify structural variants even in complex polyploid genomes.All three major types of genomic structural variation (presence–absence,copy-number,and homeologous exchange) are now known to influence phenotypes in crop plants,with examples of flowering time,frost tolerance,and adaptive and agronomic traits.In this review,we summarize the challenges of genome analysis in polyploid crops,describe the various types of genomic structural variation and the genomics technologies and data that can be used to detect them,and collate information produced to date related to the impact of genomic structural variation on crop phenotypes.We highlight the importance of genomic structural variation for the future genetic improvement of polyploid crops. 展开更多
关键词 Presence–absence VARIATION COPY-NUMBER VARIATION Homeologous exchanges Genome structure PAN-GENOME
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Spatial and seasonal distribution of intertidal macrobenthos with their biomass and functional feeding guilds in the Naf River estuary,Bangladesh 预览
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作者 Md. Abu NOMAN MAMUNUR Rashid +1 位作者 M SHAHANUL Islam M. Belal HOSSAIN 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第3期1010-1023,共14页
The Naf River estuary is one of the most productive ecological ecosystems in Bangladesh providing an important feeding area for fishes and other aquatic animals.However,detailed information on macrobenthic communities... The Naf River estuary is one of the most productive ecological ecosystems in Bangladesh providing an important feeding area for fishes and other aquatic animals.However,detailed information on macrobenthic communities is rarely available in this area.Our study focused on the seasonal and spatial variability of macrobenthic community structure with their biomass and functional guilds.In total,fortyseven taxa were identified under nine major groups and seven functional feeding guilds.Among macrobenthic taxa,Polychaeta was dominant in both seasons and all over the estuary contributing 60%of total benthos.The mean abundance of macrobenthos was higher during the pre-monsoon(2 972±1 994 inds./m^2)than the monsoon(1 572±361 inds./m^2)being maximum at mid-estuary region and minimum at upper and lower estuary regions.Of the diversity indices,density(P=0.01,P=0.003),the number of taxa(P=0.000 3,P=0.000 9)and Margalef′s Index(P=0.000 4,P=0.001)of macrobenthos were significantly different among stations and seasons.Shannon-Weiner index(P=0.009,P=0.12)and Pielou’s evenness index(P=0.03,P=0.14)had significant differences among stations but not among seasons.Cluster analysis suggested that distribution of macrofauna is strongly influenced by seasonality.Among the feeding types,carnivorous were found to be dominant at the upper and mid-estuarine regions,and herbivorous were at lower estuarine regions.Carnivorous species were dominant in both seasons.Omnivores have shown to be the most abundant feeding type in terms of biomass though herbivores were highest during monsoon. 展开更多
关键词 MACROBENTHOS seasonal VARIATION SPATIAL VARIATION feeding GUILDS BIOMASS NAF River estuary
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Anatomy of the Brachial Plexus: A Rare Variation in the Laboratory of Anatomy of Bamako (Mali) 预览
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作者 Babou Ba Abdoulaye Kanté +12 位作者 Drissa Traoré Bréhima Bengaly Mariam Daou Bréhima Coulibaly Drissa Ouattara Siaka Diallo Siaka Diakité Moumouna Koné Tata Touré Cheickh Tidiane Diallo Ousmane Ibrahim Touré Birama Togola Nouhoum Ongo?ba 《法医学与解剖学研究(英文)》 2019年第1期8-12,共5页
The brachial plexus (BP), established by the lap twigs of the last four cervical nerves and the first thoracic nerve, assures the driving and sensory innervation of the thoracic member. We bring back a case of rare an... The brachial plexus (BP), established by the lap twigs of the last four cervical nerves and the first thoracic nerve, assures the driving and sensory innervation of the thoracic member. We bring back a case of rare anatomical variation of the brachial plexus. It is a 34-year-old corpse dissected in the laboratory of anatomy of the Faculty of Medicine and Odontostomatology of Bamako in September 2017. The lap twig of the fourth cervical root (C4) participated in the constitution of the brachial plexus. The superior trunk was normally constituted. The average trunk was formed by the cervical roots C7 and C8 instead of only C7. And consequently the inferior trunk was constituted by the thoracic root T1. The posterior beam was only formed by the posterior branches of the superior and more average trunk. The medial beam was formed by all of the inferior trunk which did not give posterior branch for the formation of the posterior beam. The variations of the brachial plexus could entrain failures in the loco regional anesthesia of the brachial plexus. 展开更多
关键词 ANATOMY BRACHIAL PLEXUS VARIATION Anesthesia Surgery
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Martingale Musielak-Orlicz Hardy spaces
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作者 Guangheng Xie Yong Jiao Dachun Yang 《中国科学:数学英文版》 SCIE CSCD 2019年第8期1567-1584,共18页
In this article,we introduce the martingale Musielak-Orlicz Hardy spaces H_φ^*(■),Pφ(?),H_φ^S(■),Qφ(?)and H_φ^s(■),respectively,via the maximal function,the quadratic variation and the conditional quadratic va... In this article,we introduce the martingale Musielak-Orlicz Hardy spaces H_φ^*(■),Pφ(?),H_φ^S(■),Qφ(?)and H_φ^s(■),respectively,via the maximal function,the quadratic variation and the conditional quadratic variation of martingales.We then establish the atomic characterizations of H_φ^s(■),Pφ(■)and Qφ(■).As applications,we obtain the dual space of H_φ^s(■)and several martingale inequalities which further clarify the relations among H_φ^*(■),Pφ(■),H_φ^S(■),Qφ(■)and H_φ^s(■).Especially,as special cases,the results on atomic characterizations of H_φ^s(■),Pφ(?)and Qφ(■)as well as on the dual space of H_φ^s(■)in the weighted case are also new. 展开更多
关键词 MARTINGALE Musielak-Orlicz Hardy space maximal function QUADRATIC VARIATION CONDITIONAL QUADRATIC VARIATION atom DUALITY
COL12A1?rs970547位点基因多态性与前交叉韧带损伤相关性的Meta分析
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作者 杨磊波 段广斌 +3 位作者 卫小春 张志伟 郭鹏 张发元 《中华生物医学工程杂志》 CAS 2019年第2期148-154,共7页
目的 利用Meta分析方法对COL12A1?rs970547位点基因多态性与前交叉韧带(anterior cruciate ligament,ACL)损伤相关性进行系统评价.方法 对2018年3月之前发表的关于COL12A1?rs970547位点基因与ACL损伤的文献进行检索、收集和整理,用Meta... 目的 利用Meta分析方法对COL12A1?rs970547位点基因多态性与前交叉韧带(anterior cruciate ligament,ACL)损伤相关性进行系统评价.方法 对2018年3月之前发表的关于COL12A1?rs970547位点基因与ACL损伤的文献进行检索、收集和整理,用Meta分析的方法分析等位基因G vs A、显性模型(AG+GG)vs AA、隐性模型GG vs(AA+AG)、共显性模型AA vs GG和AA vs GA在ACL损伤组与对照组中是否有差异,以期深入揭示COL12A1?rs970547位点基因多态性与ACL损伤的联系.结果 本研究在5个团队的5份独立样本(包括患者686例和健康对照890例)的Meta分析发现,总体人群中,COL12A1?rs970547位点基因多态性与ACL损伤在等位基因G vs A[OR=1.29,95% CI (1.05,1.60),P=0. 02]、显性模型(AG+GG)vs AA[OR=1.49,95% CI(1.17,1.89),P=0. 001]、共显性模型AA vs GA[OR=1.57,95% CI(1.23,2.01),P=0. 0003]方面差异有统计学意义,可认为COL12A1?rs970547位点基因多态性与ACL损伤存在一定的关联性.单独对欧洲?高加索人种、亚洲人种进行亚组Meta分析,结果显示欧洲?高加索人种中,等位基因G vs A、各基因模型在ACL损伤组与对照组中的差别无统计学意义(P>0. 05),尚不能认为欧洲?高加索人种中COL12A1?rs970547位点基因多态性与ACL损伤存在关联性.在亚洲人种中等位基因G vs A[OR=1.76,95% CI(1.20,2.57),P=0.004]、显性模型(AG+GG)vs AA[OR=2.93,95% CI(1.58,5.44),P=0. 0007]、共显性模型AA vs GG[OR=3.92, 95% CI(1.46,10.47),P=0.000 7]和AA vs GA[OR=2.83,95% CI(1.50,5.34),P=0. 001]在ACL损伤组与对照组中的差异有统计学意义,可认为亚洲人种中COL12A1?rs970547位点基因多态性与ACL损伤存在关联性.结论 本次Meta分析显示至少在亚洲人种中,COL12A1?rs970547位点基因多态性与ACL损伤存在关联性,利用这种基因有助于发现ACL损伤新的预防及治疗策略. 展开更多
关键词 COL12A1 rs970547 多态性 单核苷酸 前交叉韧带损伤 META分析
流域尺度下地形属性对土壤质地类型变异的影响——以重庆市彭水县一小流域为例 预览
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作者 马冉 刘洪斌 武伟 《农业资源与环境学报》 CAS 北大核心 2019年第3期279-286,共8页
为探究流域尺度下地形属性对土壤质地类型变异的影响,以西南地区重庆市彭水县的一个流域为研究区,基于成土母质和地形因子,运用分类回归树(Classification and regression tree,CART)模型,对研究区1165个样点数据进行分析。结果表明:成... 为探究流域尺度下地形属性对土壤质地类型变异的影响,以西南地区重庆市彭水县的一个流域为研究区,基于成土母质和地形因子,运用分类回归树(Classification and regression tree,CART)模型,对研究区1165个样点数据进行分析。结果表明:成土母质和地形因子均对土壤质地类型有重要影响,相对重要性较高的因子排序:成土母质(PAR)>风效应(WindEff)>地形湿度指数(SAGATWI);不同母质、不同质地之间地形因子存在显著差异,风效应(WindEff)和漫射辐射(DiffuseIns)分别是奥陶系和志留系母质条件下影响土壤质地分类的相对重要性最高的地形因子;流域尺度CART模型解释率为86.3%,说明CART模型对土壤质地分类精度高。研究表明,基于成土母质和地形因子构建的模型解释效果好,影响显著,可为该地区土壤利用区划和管理提供科学依据。 展开更多
关键词 流域尺度 CART模型 母质 地形因子 土壤质地类型 变异
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Long-term variation of storm surge-associated waves in the Bohai Sea 预览
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作者 WANG Yanping LIU Yongling +2 位作者 MAO Xinyan CHI Yutao JIANG Wensheng 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第6期1868-1878,共11页
When investigating the long-term variation of wave characteristics as associated with storm surges in the Bohai Sea,the Simulating Waves Nearshore(SWAN)model and Advanced CIRCulation(ADCIRC)model were coupled to simul... When investigating the long-term variation of wave characteristics as associated with storm surges in the Bohai Sea,the Simulating Waves Nearshore(SWAN)model and Advanced CIRCulation(ADCIRC)model were coupled to simulate 32 storm surges between 1985 and 2014.This simulation was validated by reproducing three actual wave processes,showing that the simulated significant wave height(SWH)and mean wave period agreed well with the actual measurements.In addition,the long-term variations in SWH,pattems in SWH extremes along the Bohai Sea coast,the 100-year retum period SWH extreme distribution,and waves conditional probability distribution were calculated and analyzed.We find that the trend of SWH extremes in most of the coastal stations was negative,among which the largest trend was-0.03 m/a in the western part of Liaodong Bay.From the 100-year return period of the SWH distribution calculated in the Gumbel method,we find that the SWH extremes associated with storm surges decreased gradually from the center of the Bohai Sea to the coast.In addition,the joint probability of wave and surge for the entire Bohai Sea in 100-year return period was determined by the Gumbel logistic method.We therefore,assuming a minimum surge of one meter across the entire Bohai Sea,obtained the spatial SWH distribution.The conclusions of this study are significant for offshore and coastal engineering design. 展开更多
关键词 SIGNIFICANT wave height(SWH) STORM SURGE long-term variation coupled models Bohai Sea
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Domestication of marine microalga Nannochloropsis oceanica to freshwater medium and the physiological responses 预览
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作者 GUO Li LIANG Sijie +3 位作者 ZHANG Zhongyi LIU Hang WANG Songwen YANG Guanpin 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第4期1353-1362,共10页
Marine microalga Nannochloropsis oceanica LAMB0001 were domesticated (~730 generations,~two days each) to adapt freshwater BG11 medium. A number of freshwater medium adapted colony-derived strains were obtained. The s... Marine microalga Nannochloropsis oceanica LAMB0001 were domesticated (~730 generations,~two days each) to adapt freshwater BG11 medium. A number of freshwater medium adapted colony-derived strains were obtained. The strains were verified phylogenetically to be N. oceanica LAMB0001 based on the 18S ribosomal RNA gene. Freshwater-medium adapted strain (FA1) grew faster in the BG11 medium prepared with freshwater than wild-type N. oceanica grew in f/2 medium prepared with seawater. We assumed that (1) the expression patterns of the genes that expressed differentially between FA1 and the wild-type N. oceanica exposing to the BG11 medium (WT-F) have been reprogrammed;(2) the physiological processes in which these genes involved have been modified;and (3) a Gene Ontology (GO) term or a KEGG pathway enriched by DEGs between FA1 and WT-F has been up- or down-regulated if it was enriched simultaneously by up- or down-regulated DEGs between FA1 and WT-F, respectively. Under these assumptions, we found that FA1 reprogrammed the expression patterns of a set of genes that involved in cell adhesion, membrane and membrane integrity, material transportation, cell movement, and cellular signaling network. These changes in cellular functions and metabolic pathways indicate that the microalga modified its gene expression pattern in a wide function range and at a high regulation rank in order to adapt to the freshwater medium. It is feasible to domesticate marine microalgae to a freshwater habitat, which may aid to modify their cultivation performances. 展开更多
关键词 NANNOCHLOROPSIS oceanica DOMESTICATION ACCLIMATION ADAPTATION genetic variation
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红锥优树二代家系抗逆性苗期选择研究 预览
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作者 申文辉 谭长强 +4 位作者 劳庆祥 郝海坤 曹艳云 郑威 黄志玲 《西南林业大学学报》 CAS 北大核心 2019年第2期11-17,共7页
通过对29个红锥优树二代家系苗高、地径及抗性生理指标进行测定,运用隶属函数法对抗逆性优良家系进行筛选和评价。结果表明:各指标29个家系间均存在较大差异。苗高为36.5~74.8 cm,地径为5.03~8.58 mm,可溶性糖含量为3.37%~5.84%,淀粉含... 通过对29个红锥优树二代家系苗高、地径及抗性生理指标进行测定,运用隶属函数法对抗逆性优良家系进行筛选和评价。结果表明:各指标29个家系间均存在较大差异。苗高为36.5~74.8 cm,地径为5.03~8.58 mm,可溶性糖含量为3.37%~5.84%,淀粉含量为2.01%~4.09%,可溶性蛋白含量为20.4~38.1 mg/g,脯氨酸含量为2.66~5.04μg/g,丙二醛含量为15.6~87.5 nmol/g,过氧化物酶含量为12.3~88.0μ/(g·min),超氧化物歧化酶含量为53.2~82.9 U/g。各抗逆性指标各红锥家系间均存在显著差异。采用多指标的综合评价方法筛选出10个家系为抗逆性优良家系,同时结合苗高及地径生长指标,进一步筛选出P3、B2、A7、B5家系的速生抗逆性最强。 展开更多
关键词 红锥 家系 苗期 变异 选择 抗性生理
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不同种源黑果枸杞苗期生长差异分析 预览
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作者 林治国 《林业勘查设计》 2019年第3期57-59,共3页
本文研究了不同种源黑果枸杞苗期的生长差异,为优良种源的选择提供依据。结果表明,3个种源中甘肃的出苗快,出苗率高达95.12%,新疆的较小。苗高和地径生长呈“S”型生长曲线,甘肃的幼苗苗高和地径生长量大,整个生长期生长速率较快,其次... 本文研究了不同种源黑果枸杞苗期的生长差异,为优良种源的选择提供依据。结果表明,3个种源中甘肃的出苗快,出苗率高达95.12%,新疆的较小。苗高和地径生长呈“S”型生长曲线,甘肃的幼苗苗高和地径生长量大,整个生长期生长速率较快,其次为青海,而新疆的最小;不同种源间苗高和地径差异显著或极显著。3个种源内苗高和地径存在着一定的变异,以甘肃种源的变异较大,新疆的变异较小。 展开更多
关键词 黑果枸杞 种源 生长性状 变异
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Effects of seasonal air temperature variation on airflow and surrounding rock temperature of mines 预览
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作者 Xin Yi Lifeng Ren +4 位作者 Li Ma Gaoming Wei Wencong Yu Jun Deng Chimin Shu 《国际煤炭科学技术学报:英文版》 2019年第3期388-398,共11页
In underground mines, high air temperatures in the summer months lead to an increase in inlet airflow temperatures. This leads to seasonal thermal pollution in the mines. This paper examines the dynamics and effects o... In underground mines, high air temperatures in the summer months lead to an increase in inlet airflow temperatures. This leads to seasonal thermal pollution in the mines. This paper examines the dynamics and effects of seasonal variation in surface air temperatures and surrounding rock temperatures in deep coal mines. It also examines temperature variations in the main ventilation circuit, working face, and surrounding rock. The study results revealed that airflow temperatures were significantly affected by seasonal air temperature variations. The greater the distance was between the inlet and the wellhead of the ventilation shaft, the less the effect was on temperature. Moreover, slight temperature variations (1.0-3.0 ℃) were observed between various points on the return route during the summer months. Airflow temperatures along the airflow inlet to the return route of the working face first decreased, but then increased. The temperature field of the surrounding rock increased gradually with increased distance between the mine roadway and inlet, with recorded rock temperatures as high as 40.53 ℃. The radius of the heat-adjusting layer was between 28 and 33 m. 展开更多
关键词 SEASONAL VARIATION Fiber optic TEMPERATURE measurement Real-time monitoring Deep coal mine Thermal pollution Heat-adjusting layer
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Identifying Intraspecific Variation in Venom Yield of Chinese Cobra(Naja atra) from Ten Populations in Mainland China
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作者 Jianfang GAO Yin YIN +4 位作者 Yanfu QU Jin WANG Longhui LIN Hongliang LU Xiang JI 《亚洲两栖爬行动物研究:英文版》 SCIE CSCD 2019年第1期32-40,共9页
Detailed information on venom yield is helpful in preparing antivenoms and treating snakebites, but such information is lacking for many species of venomous snakes. The Chinese cobra(Naja atra) is a large sized, venom... Detailed information on venom yield is helpful in preparing antivenoms and treating snakebites, but such information is lacking for many species of venomous snakes. The Chinese cobra(Naja atra) is a large sized, venomous snake commonly found in southeastern China, where it causes a heavy burden of snakebites. To examine the effects of various factors(morphology, sex, age, season, and geographical origin) on the venom yield in this snake, we collected venom samples of 446 individuals(426 adults and 20 neonates) from 10 populations of N. atra over an eightyear period. We used two variables, lyophilized venom mass(venom yield) and solid content of venom(% solids), to quantify the venom yield. We used linear regression analysis to check if venom yield was related to morphological factors, one-way ANOVA and one-way ANCOVA to detect the sexual, ontogenetic, and geographic variation in venom yield, and repeated-measures ANOVA to examine seasonal shifts in venom yield. Our results indicate that venom yield of N. atra is positively related to the morphological traits examined, with male snakes expelling more venom than females. Venom yield in N. atra was age-related, with elder snakes always expelling more venom than younger ones. Geographic variation in venom yield was also observed, while seasonal variation was not. The solid content of venom was lower in males than in females, but this was not related to morphology, season, age, or geography. Our findings suggest that venom yield in N. atra is influenced by multiple factors, as well as by the interactions among these factors. 展开更多
关键词 Naja atra VENOM YIELD INTRASPECIFIC variation SNAKEBITE
青藏高原东北部春季冷空气次数变化及其诊断分析 预览
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作者 杨昭明 时盛博 +1 位作者 段丽君 张调风 《中国农学通报》 2019年第27期128-136,共9页
利用青藏高原东北部68个台站1961—2015年春季(3—5月)地面气温观测资料,统计整理了春季各月冷空气过程的强度指数I(含次数)序列,应用气候诊断方法分析了区域冷气次数的变化特征及其成因。结果表明:在变化的趋势上,1961—2015年青藏高... 利用青藏高原东北部68个台站1961—2015年春季(3—5月)地面气温观测资料,统计整理了春季各月冷空气过程的强度指数I(含次数)序列,应用气候诊断方法分析了区域冷气次数的变化特征及其成因。结果表明:在变化的趋势上,1961—2015年青藏高原东北部春季冷空气过程次数的气候变化倾向率为-0.290次/10 a,减少的趋势不显著;柴达木盆地区、南部区的减少趋势与青藏高原东北部一致,东部区的增多趋势与青藏高原东北部相反。在周期变化上,青藏高原东北部和3个分区,3、5、7、8年准周期出现的频次相对较高,25年等其他准周期出现的频次相对较低。1991—2015年(1961—1980年),500 hPa层贝加尔湖地区春季高度值持续偏高(偏低)是导致青藏高原东北部春季冷空气过程次数持续偏少(偏多)的主要成因之一。春季乌拉尔山高压脊、巴尔喀什湖至贝加尔湖低压槽、里海至咸海高压脊持续偏强,容易引导北方南下的冷空气从偏西北路径和偏北路径影响中国,青藏高原东北部位于冷空气南下的通道上,冷空气过程次数容易偏多;相反,冷空气过程容易次数偏少。 展开更多
关键词 冷空气次数 变化 诊断分析 环流因子 冷空气活动 青藏高原
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Using proximal sensor data for soil salinity management and mapping 预览
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作者 GUO Yan ZHOU Yin +5 位作者 ZHOU Lian-qing LIU Ting WANG Lai-gang CHENG Yong-zheng HE Jia ZHENG Guo-qing 《农业科学学报:英文版》 SCIE CAS CSCD 2019年第2期340-349,共10页
Over the past five decades, increased pressure caused by the rapidly growing population has resulted in a reclamation of agricultural and urban buffer zones along China’s coastline. However, information about the spa... Over the past five decades, increased pressure caused by the rapidly growing population has resulted in a reclamation of agricultural and urban buffer zones along China’s coastline. However, information about the spatio–temporal variation of soil salinity in these reclaimed regions is limited. As such, obtaining this information is crucial for mapping the variation in saline areas and to identify suitable salinity management strategies. In this study, we employed EM38 data to conduct digital soil mapping of spatio–temporal variation and map these variations of different site-specific zones. The results indicated that the distribution of soil salinity was heterogeneous in the middle of, and that the leaching of salts was significant at the edges of, the study field. Afterwards, fuzzy-k means algorithm was used to divide the site-specific management zones within the time series apparent soil electrical conductivity(ECa) data and the spatial correlations of variation. We concluded that two management zones are optimal to guide precision management. Zone A had an average salinity level of about 165 mS m–1, in which salt-tolerant crops, such as cotton and barley can grow normally, while crops such as soybean and cowpeas may be planted using leaching and increasing the mulching film methods to reduce the accumulation of salt in surface soil. In Zone B, there was a low salinity level with a mean of 89 mS m–1 for ECa, which allows for rice, wheat, and a wide range of vegetables to be grown normally. In such situations, measures such as an optimized combination of irrigation and drainage, as well as soil amendment can be taken to adjust and control the salt content. Particularly, flattening the land with a large-scale machine was used to improve the ability of micro-topography to influence salt migration;rice and other dry, land crops were planted in rotation in combination with utilizing salt-leaching multiple times to speed up desalinization. 展开更多
关键词 APPARENT SOIL electrical conductivity(ECa) SOIL salinity EM38 spatial variation MANAGEMENT zone
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Dimensional Variation Modeling of Aircraft Compliant Part Assembly Considering Clamping Force Change 预览
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作者 TAN Changbai ZHANG Wei WANG Zhiguo 《南京航空航天大学学报:英文版》 EI CSCD 2019年第2期298-305,共8页
Compliant parts are widely applied to aircraft structures.Due to the ease of deformation of compliant parts in assembly,the prediction of assembly variation is especially important for assembly quality control.A dimen... Compliant parts are widely applied to aircraft structures.Due to the ease of deformation of compliant parts in assembly,the prediction of assembly variation is especially important for assembly quality control.A dimensional variation model considering the clamping force change in assembly is proposed based on the method of influence coefficient(MIC).First,the assembly process is decomposed into several steps including positioning,clamping,joining,and spring-back.Then,the force-displacement relationship is formulated according to the varied force conditions on the parts in each assembly step.Finally,two examples are illustrated to validate the proposed assembly variation model.The results show the impact of clamping force change is significant on the assembly variation,and the proposed model can predict the assembly variation more accurately than the referred method without clamping force correction at the over-constrained locating points of fixture. 展开更多
关键词 AIRCRAFT dimensional variation compliant parts CLAMPING force CHANGE method of influence coefficient(MIC)
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基于DI指数的佛山市气象干旱变化趋势分析 预览
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作者 麦雪湖 梁华玲 +1 位作者 麦文强 程银琳 《中低纬山地气象》 2019年第3期75-77,共3页
该文根据逐日气象干旱指数DI指数统计佛山1959—2017年气象干旱日数,采用“二项式系数加权平均法”进行趋势分析,结合M-K检验和小波分析等方法分析气候突变和周期变化,对佛山市59a的气象干旱日数变化趋势进行分析研究。结果表明:近59a... 该文根据逐日气象干旱指数DI指数统计佛山1959—2017年气象干旱日数,采用“二项式系数加权平均法”进行趋势分析,结合M-K检验和小波分析等方法分析气候突变和周期变化,对佛山市59a的气象干旱日数变化趋势进行分析研究。结果表明:近59a佛山年气象干旱日数总体呈减少的趋势,2015年以后年气象干旱日数呈显著减少的趋势,2010—2011年是气象干旱日数突变减少的开始时段;年气象干旱日数存在着3a、7a及20a的周期时间尺度,准3a的短周期存在于1980年前,准7a的周期出现在1980年后,20a的周期有着最强的振荡,是年气象干旱日数变化的首要主周期。 展开更多
关键词 气象干旱 变化趋势 佛山
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2014-2017年中国部分地区PEDV流行株S基因遗传进化分析
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作者 郑慧华 张鸿鑫 +3 位作者 韩昊莹 乔涵 赵宇 陈红英 《安徽农业大学学报》 CAS CSCD 2019年第2期249-255,共7页
参考GenBank中PEDV经典CV777毒株基因组序列设计特异性引物,采用RT-PCR方法对临床采集的疑似PEDV样品进行S基因扩增、克隆和测序,拼接获得30条完整S基因序列,并进行遗传进化及同源性分析。结果显示,获得的30条PEDV S基因与25个参考株S... 参考GenBank中PEDV经典CV777毒株基因组序列设计特异性引物,采用RT-PCR方法对临床采集的疑似PEDV样品进行S基因扩增、克隆和测序,拼接获得30条完整S基因序列,并进行遗传进化及同源性分析。结果显示,获得的30条PEDV S基因与25个参考株S基因的核苷酸相似性介于93.6%~99.8%;且各流行毒株与经典毒株比较,具有多处的点突变、插入和缺失。与其他参考株相比,S1区存在157个氨基酸突变位点,占总数的65.7%(157/239),暗示PEDV的S1区域比S2区域易发生变异;表明目前中国PEDV流行株已经发生了变异,在一定程度揭示了免疫猪群仍然发病的原因。 展开更多
关键词 PEDV S基因 遗传进化分析 变异
大花序桉种源幼龄材木材物理性质变异 预览
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作者 余玉珠 苏远玉 +4 位作者 陆艳柳 任世奇 杨中宁 卢翠香 周维 《桉树科技》 2019年第2期9-15,共7页
用伐倒木取样,按国家标准制作测定试件,研究6a生大花序桉9个种源木材物理性质在种源间、树干高度及径向上的变异规律。结果表明:大花序桉木材树皮率、横向全干缩率、差异干缩和体积全干缩率在种源间均存在显著差异;各种源木材密度在树... 用伐倒木取样,按国家标准制作测定试件,研究6a生大花序桉9个种源木材物理性质在种源间、树干高度及径向上的变异规律。结果表明:大花序桉木材树皮率、横向全干缩率、差异干缩和体积全干缩率在种源间均存在显著差异;各种源木材密度在树干高度上无明显规律,大部分种源木材密度沿髓心向外逐渐增大。6a生的大花序桉木材差异干缩属中级。 展开更多
关键词 大花序桉 幼龄材 物理性质 变异
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