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On Similarities and Differences between Relative Pronouns in Relative Clauses
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作者 黄立进 《海外英语》 2011年第14期342-343,共2页
This paper,in two installments,attempts to clarify the finer points in the similarities and differences in the usage of relative pronouns,who,that and which,while they are in relative clauses.They are illustrated and ... This paper,in two installments,attempts to clarify the finer points in the similarities and differences in the usage of relative pronouns,who,that and which,while they are in relative clauses.They are illustrated and justified with examples.The paper,through the comparison of the usages of who,that and which,has shown their similarities and differences from one another.It will enable us to master their usages and help us in studying relative clauses. 展开更多
关键词 relative PRONOUN SIMILARITY difference USAGE relative CLAUSE
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A Construction of Relative Difference Set
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作者 ZHANGXi-yong HANWen-bao 《Chinese Quarterly Journal of Mathematics》 CSCD 2004年第3期273-279,共7页
In this paper, we give a construction of RDS in Galois ring by using some bent function, and obtain the equivalent relationship between RDS and a kind of bent function. At the same time, its existence is demonstrated.
关键词 Galois ring BENT relative set difference set
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Second-order divided difference filter for vision-based relative navigation
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作者 王小刚 崔乃刚 郭继峰 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2011年第3期16-20,共5页
A second-order divided difference filter (SDDF) is derived for integrating line of sight measurement from vision sensor with acceleration and angular rate measurements of the follower to estimate the precise relative ... A second-order divided difference filter (SDDF) is derived for integrating line of sight measurement from vision sensor with acceleration and angular rate measurements of the follower to estimate the precise relative position,velocity and attitude of two unmanned aerial vehicles (UAVs).The second-order divided difference filter which makes use of multidimensional interpolation formulations to approximate the nonlinear transformations could achieve more accurate estimation and faster convergence from inaccurate initial conditions than standard extended Kalman filter.The filter formulation is based on relative motion equations.The global attitude parameterization is given by quarternion,while a generalized three-dimensional attitude representation is used to define the local attitude error.Simulation results are shown to compare the performance of the second-order divided difference filter with a standard extended Kalman filter approach. 展开更多
关键词 relative navigation second-order divided difference filter vision sensor unmanned aerial vehicle formation flight
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Clustering Categorical Data Based on Within-Cluster Relative Mean Difference
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作者 Jinxia Su Chunjing Su 《Open Journal of Statistics》 2017年第2期173-181,共9页
The clustering on categorical variables has received intensive attention. In dataset with categorical features, some features show the superior performance on clustering procedure. In this paper, we propose a simple m... The clustering on categorical variables has received intensive attention. In dataset with categorical features, some features show the superior performance on clustering procedure. In this paper, we propose a simple method to find such distinctive features by comparing pooled within-cluster mean relative difference and then partition the data upon such features and give subspace of the subgroups. The applications on zoo data and soybean data illustrate the performance of the proposed method. 展开更多
关键词 CLUSTERING CATEGORICAL Variable Distinctive Attribute Pooled Within-Cluster Mean relative difference Hamming Distance
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Quantitative prediction of oil saturation of unconsolidated sandstone reservoir based on time-lapse seismic “relative difference method”: Taking Zeta oil field in West Africa as an example
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作者 LU Hongmei XU Hai +1 位作者 WO Yujin GU Ning 《Petroleum Exploration and Development》 2019年第2期426-434,共9页
In view of the disadvantage that the absolute difference of time-lapse seismic(the difference between monitoring data and base data) is not only related to the change of oil saturation, but also closely related to the... In view of the disadvantage that the absolute difference of time-lapse seismic(the difference between monitoring data and base data) is not only related to the change of oil saturation, but also closely related to the thickness of reservoir, a time-lapse seismic "relative difference method"(the ratio of monitoring data to base data) not affected by the thickness of reservoir but only related to the change of fluid saturation, is proposed through seismic forward modeling after fluid displacement simulation. Given the same change of fluid saturation, the absolute difference of time-lapse seismic conforms to the law of "tuning effect" and seismic reflection of "thin bed", and the remaining oil prediction method based on absolute difference of time-lapse seismic is only applicable to the reservoirs with uniform thickness smaller than the tuning thickness or with thickness greater than the tuning thickness. The relative difference of time-lapse seismic is not affected by reservoir thickness, but only related to the change of fluid saturation. It is applicable to all the deep-sea unconsolidated sandstone reservoirs which can exclude the effect of pressure, temperature, pore type and porosity on seismic. Therefore, the relation between the relative difference of time-lapse seismic and the change of fluid saturation, which is obtained from seismic forward modeling after Gassmann fluid displacement simulation, can be used to quantitatively predict the change of reservoir water saturation and then the distribution of the remaining oil. The application of this method in deep sea Zeta oil field in west Africa shows that it is reasonable and effective. 展开更多
关键词 time-lapse seismic remaining OIL quantitative prediction unconsolidated sandstone reservoir fluid displacement absolute difference relative difference ZETA OIL field WEST AFRICA
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不同产地‘晋谷21’小米品质特性差异研究
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作者 田翔 郑婷婷 +2 位作者 郭伟 乔治军 刁现民 《山西农业大学学报(自然科学版)》 北大核心 2025年第1期61-72,共12页
[目的]探明不同生态环境小米在营养及加工等品质方面的差异,有利于实现优质谷子品种的合理布局,改良小米品质。[方法]以山西、陕西、宁夏、甘肃、北京的24个产地种植的谷子品种‘晋谷21’去壳后所得小米为材料,对其营养组分、淀粉糊化... [目的]探明不同生态环境小米在营养及加工等品质方面的差异,有利于实现优质谷子品种的合理布局,改良小米品质。[方法]以山西、陕西、宁夏、甘肃、北京的24个产地种植的谷子品种‘晋谷21’去壳后所得小米为材料,对其营养组分、淀粉糊化特性及小米粥、小米饭质构特性进行对比分析,并运用灰色关联分析评价法对其营养组分进行综合评价。[结果]不同产地的‘晋谷21’小米间纤维素和灰分含量变异系数最大,黄色素、脂肪、蛋白质、直链淀粉含量也存在较大差异,24个产地的‘晋谷21’小米淀粉及蛋白质含量整体较高。不同产地间小米粥浓稠度差异较大,小米饭蒸煮品质各有差异,小米凝聚力差异不大,表现出较好的一致性。山西临县和陕西的志丹、定边、米脂的小米崩解值高于其它产地;山西临县、北京延庆、陕西定边的小米回生值明显高于其它产地。灰色关联分析结果显示,各营养成分的权重表现为淀粉含量>蛋白质含量>脂肪含量>黄色素含量>直链淀粉含量>纤维素含量>灰分含量,各产地间的关联度较为接近,其综合品质相差不大。其中,山西兴县的‘晋谷21’与理想品种最为接近,综合品质最好;山西汾阳的‘晋谷21’与理想品种相差最大。[结论]生态环境对‘晋谷21’小米品质影响较大,且对多种营养组分影响较大。除基因筛选方法外,还可通过生态环境条件改善培育优良谷子品种。 展开更多
关键词 小米 产地差异 品质特性 灰色关联分析
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Research on the Relationship between British and American Cultural Differences and American Literature Comment 被引量:1
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作者 Hongling WANG 《International Journal of Technology Management》 2015年第5期66-68,共3页
The influence of cultural differences by race and treat people with an understanding of the work will be carried out from different angles, which leads to the same people for a work of literary criticism. Expand artic... The influence of cultural differences by race and treat people with an understanding of the work will be carried out from different angles, which leads to the same people for a work of literary criticism. Expand article on the impact of cultural differences between British and American English and American literary criticism on this topic research, by the characteristics of English and American Literature and American Literature and commentary of the corresponding description. It is to analyze the impact of cultural differences on the Anglo-American literary criticism, so that people understand the culture differences in the importance of the influence of the Anglo-American literary criticism. 展开更多
关键词 Anglo-American Cultural differences Anglo-American Literary Criticism RELATIONS
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Some new generalized difference sequence spaces defined by a sequence of moduli
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作者 Vakeel A Khan 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2011年第1期104-108,共5页
The idea of difference sequence sets X(△) = {x = (xk) : △x ∈ X} with X = l∞, c and co was introduced by Kizmaz [12]. In this paper, using a sequence of moduli we define some generalized difference sequence sp... The idea of difference sequence sets X(△) = {x = (xk) : △x ∈ X} with X = l∞, c and co was introduced by Kizmaz [12]. In this paper, using a sequence of moduli we define some generalized difference sequence spaces and give some inclusion relations. 展开更多
关键词 difference sequence space sequence of moduli inclusion relation.
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The Exploration to the Historical Origin of Differences between Urban and Rural Areas in China
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作者 ZHU Hong-liang ZHANG Rui-qing 《Asian Agricultural Research》 2011年第1期118-121,126,共5页
In order to understand the historical origins of encircling the cities from the rural areas implemented by the Communist Party of China and the current dual structures of urban and rural development, urban-rural diffe... In order to understand the historical origins of encircling the cities from the rural areas implemented by the Communist Party of China and the current dual structures of urban and rural development, urban-rural differences are analyzed from the four aspects of production mode, management mode, culture and social division of labor. Industrial development in modern times has promoted the modernization of urban production in China. But the rural areas still maintain their traditional self-sufficient natural economy. After the Opium War, the process of modernization of city politics is promoted by more economic elements of capitalism and the formation of Chinese bourgeoisie. During the management of urban modernization, rural areas still adopt the traditional self-management mode. In the aspect of culture, city is the center of development, having large population, developed traffic, and prosperous culture. But the village is lack of information and its culture is relatively backward. In modern times, affected by the foreign capitalist, urban area has become the center of modern productivity. After separating from agriculture, handicraft industry has transferred into urban areas and the social division of labor in both urban and rural areas has shown great changes. Thus, a new pattern of "Urban Industry, Rural Agriculture" has formed. 展开更多
关键词 Urban and rural areas RELATION difference HISTORY China
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Rolling velocity and relative motion of particle detector in local granular flow
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作者 Ran Li Bao-Lin Liu +1 位作者 Gang Zheng Hui Yang 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第11期388-394,共7页
The velocity of a particle detector in granular flow can be regarded as the combination of rolling and sliding velocities.The study of the contribution of rolling velocity and sliding velocity provides a new explanati... The velocity of a particle detector in granular flow can be regarded as the combination of rolling and sliding velocities.The study of the contribution of rolling velocity and sliding velocity provides a new explanation to the relative motion between the detector and the local granular flow.In this study,a spherical detector using embedded inertial navigation technology is placed in the chute granular flow to study the movement of the detector relative to the granular flow.It is shown by particle image velocimetry(PIV)that the velocity of chute granular flow conforms to Silbert’s formula.And the velocity of the detector is greater than that of the granular flow around it.By decomposing the velocity into sliding and rolling velocity,it is indicated that the movement of the detector relative to the granular flow is mainly caused by rolling.The rolling detail shown by DEM simulation leads to two potential mechanisms based on the position and drive of the detector. 展开更多
关键词 local velocity distribution rolling velocity inertial navigation technology relative velocity dependent(rvd)rolling friction
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Gender Differences in the Pharmacokinetics of Oral Drugs
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作者 Miriam del Carmen Carrasco-Portugal Francisco Javier Flores-Murrieta 《Pharmacology & Pharmacy》 2011年第1期31-41,共11页
Establishment of rational dosage regimens requires the knowledge of pharmacokinetics and pharmacodynamics in the target population. It has been established that side effects produced by drugs are more frequent in wome... Establishment of rational dosage regimens requires the knowledge of pharmacokinetics and pharmacodynamics in the target population. It has been established that side effects produced by drugs are more frequent in women than in men. This may be due to two possibilities, one is that normalized dose received by women is higher than men and the other is that anatomical and physiological characteristics are a quite different. In this review, some aspects that may play a role in the generation of such differences are analyzed, including the impact on absorption, distribution, metabolism and excretion of drugs. Most of the changes can be explained by differences in volume of distribution and systemic clear- ance, however, presystemic clearance also seems to play a role in such dissimilarities. The final result, in general, is that women have higher plasma levels of drugs and usually these differences are reduced or abolished when data are normalized by the body weight, since both, volume of distribution and systemic clearance are influenced by it;however, there are some cases in which differences remain. Further research oriented to establish the role of each of the ana- tomical and physiological differences in the oral pharmacokinetics of drugs is warranted. 展开更多
关键词 Gender-Related differenceS ORAL PHARMACOKINETICS SEX differenceS
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Tidal harmonic analysis of TOPEX/POSEIDON data in the Northwest Pacific by introducing difference-ratio relations
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作者 刘克修 马继瑞 +2 位作者 韩桂军 范振华 许崇金 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2002年第1期33-44,共12页
The difference-ratio relations are introduced to separate tidal constituents that are aliaseddue to the sampling interval and sampling span of the TOPEX/POSEIDON altimeter. It is found that some tidal constituents suc... The difference-ratio relations are introduced to separate tidal constituents that are aliaseddue to the sampling interval and sampling span of the TOPEX/POSEIDON altimeter. It is found that some tidal constituents such as K_1 and SSA, though aliased at along track points, are not aliased at crossover points beeause the data at crossover points are double those at along track points. So the harmonic analysis method can be employed directly for the analysis of time series at crossover points. Then the difference-ratio relations from crossover points are introduced to analyze the time series at along track points. The TOPEX/POSEIDON data in the Northwest Pacific are analyzed with this method. The results from this method agree well with tidal constants from tidal gauges. 展开更多
关键词 Tidal harmonic analysis TOPEX/POSEIDON the Northwest Pacific difference-ratio relations
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特发性肺纤维化肺内相关共病异病同证基因组生物信息学分析
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作者 刘勇明 吕晓东 +6 位作者 庞立健 臧凝子 梁元钰 王靖宇 王佳然 邹吉宇 盛野 《中国中医药信息杂志》 CAS CSCD 2024年第12期20-26,共7页
目的通过基因组生物信息学分析探讨特发性肺纤维化(IPF)肺内相关共病(肺动脉高压、阻塞性睡眠呼吸暂停综合征、慢性阻塞性肺疾病、肺癌)异病同证生物学基础。方法下载GSE110147、GSE113439、GSE135917、GSE106986和GSE118370数据集,筛... 目的通过基因组生物信息学分析探讨特发性肺纤维化(IPF)肺内相关共病(肺动脉高压、阻塞性睡眠呼吸暂停综合征、慢性阻塞性肺疾病、肺癌)异病同证生物学基础。方法下载GSE110147、GSE113439、GSE135917、GSE106986和GSE118370数据集,筛选各病例组与对照组的差异基因,运用Cytoscape3.10.0软件进行拓扑分析以筛选核心基因,运用OmicShare平台对核心基因进行GO和KEGG通路富集分析。结果共筛选出IPF肺内相关共病核心基因23个。GO富集分析显示,核心基因生物过程主要富集于细胞进程、代谢进程、生物调控/生物进程调控、发育进程、底物定位进程、刺激反应、免疫系统进程、信号转导,细胞组分主要富集于细胞解剖实体、含蛋白复合物,分子功能主要富集于结合途径、酶催化活性、结构分子活性、分子适配器活性、分子功能调节因子、转录调控因子活性;KEGG通路富集分析显示,核心基因主要富集于真核生物核糖体的生物合成、糖尿病并发症AGE-RAGE信号通路、Th17细胞分化、JAK-STAT信号通路、RNA聚合酶、中性粒细胞胞外诱捕网形成等信号通路。结论运用基因组生物信息学分析探讨IPF肺内相关共病核心基因及信号通路,可在一定程度上揭示IPF肺内相关共病异病同证作用机制。 展开更多
关键词 特发性肺纤维化 肺内相关共病 异病同证 基因组学 生物信息学
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省内异地就医按疾病诊断相关分组入组病例的住院费用分析
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作者 苏会璇 叶沛仪 饶苑平 《中国当代医药》 CAS 2024年第34期91-95,共5页
目的探讨按疾病诊断相关分组(DRG)付费下省内异地医保与本地医保住院费用的异同。方法收集2022年4月至2023年10月北海市人民医院结算的省内异地医保4610例病例数据和本地医保住院69619例病例数据资料进行回顾性分析,排除不符合DRG支付... 目的探讨按疾病诊断相关分组(DRG)付费下省内异地医保与本地医保住院费用的异同。方法收集2022年4月至2023年10月北海市人民医院结算的省内异地医保4610例病例数据和本地医保住院69619例病例数据资料进行回顾性分析,排除不符合DRG支付规则的住院病例(职工生育及生育并发症、急诊留观、家庭病床、离休人员、诊断新型冠状病毒感染和住院天数>61 d)和不能正常入组DRG的歧义组、空白组。结果省内异地医保的DRG病种覆盖面和病例组合指数低于本地医保,个人负担和自费项目费用及其占比均高于本地医保,例均药品费用低于本地医保,差异均有统计学意义(P<0.05)。省内异地医保恶性增生性疾患的靶向及免疫治疗、化学治疗和其他治疗的例均总住院费用高于本地医保,差异有统计学意义(P<0.05)。结论DRG医保支付在控制省内异地医保总住院费用和本地医保有相同的效果,政策培训及解读仍需继续深入临床。 展开更多
关键词 医保住院 省内异地 按疾病诊断相关分组 住院费用
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DRG付费下甲状腺癌大手术患者支付差影响因素分析 被引量:1
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作者 林振威 吴风琴 +2 位作者 程斌 王锦毓 陈洁 《中国医疗保险》 2024年第5期80-84,共5页
目的:分析疾病诊断相关分组(DRG)付费下甲状腺癌大手术患者支付差的影响因素,为医院合理控制医疗成本提供参考。方法:选取某三甲医院2020—2022年所有甲状腺癌大手术组(KD1)患者作为研究对象,利用描述性统计、单因素方法和二分类Logisti... 目的:分析疾病诊断相关分组(DRG)付费下甲状腺癌大手术患者支付差的影响因素,为医院合理控制医疗成本提供参考。方法:选取某三甲医院2020—2022年所有甲状腺癌大手术组(KD1)患者作为研究对象,利用描述性统计、单因素方法和二分类Logistic回归分析患者支付差的影响因素。结果:住院天数、并发症与合并症、手术部位、是否颈清、是否腔镜、药品占比、耗材占比和手术占比是影响甲状腺癌大手术患者支付差的主要因素。结论:DRG改革下,医院应推广价值医疗的理念,促进临床规范诊疗,并加强病案质量审核,保证DRG正确入组,在此基础上合理调整费用结构,科学管控药耗成本,助力医院高质量发展。 展开更多
关键词 疾病诊断相关分组 支付差 甲状腺癌 住院费用
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有机肥料标准的思考与建议
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作者 后德家 李庆 +1 位作者 李祥 陈龙 《中国标准化》 2024年第14期108-112,共5页
本文根据几个有机肥料标准文本,分析了有机肥料标准之间的区别与联系,讨论了有机肥料的定义、指标及其测定方法。针对有机肥料标准的频繁修订,标准之间指标、测定方法的不统一,提出思考和建议。建议国家在制(修)订标准时应采用慎之又慎... 本文根据几个有机肥料标准文本,分析了有机肥料标准之间的区别与联系,讨论了有机肥料的定义、指标及其测定方法。针对有机肥料标准的频繁修订,标准之间指标、测定方法的不统一,提出思考和建议。建议国家在制(修)订标准时应采用慎之又慎的科学态度,以指导生产实践为前提,以免混乱市场,挫伤生产者和消费者的热情。 展开更多
关键词 有机肥料标准 区别与联系 思考 建议
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志愿服务参与能培育大学生非认知能力吗——基于追踪调研和双重差分技术的因果分析
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作者 胡平平 牛新春 汪卫平 《复旦教育论坛》 CSSCI 北大核心 2024年第2期54-63,共10页
已有众多研究基于人格特质理论和经验学习理论,揭示了志愿服务参与和大学生非认知能力存在双向因果关系。本文基于湖南省高校大学生发展追踪调查数据,采用双重差分法检验志愿服务参与和非认知能力的因果关系,以揭示志愿服务参与究竟是... 已有众多研究基于人格特质理论和经验学习理论,揭示了志愿服务参与和大学生非认知能力存在双向因果关系。本文基于湖南省高校大学生发展追踪调查数据,采用双重差分法检验志愿服务参与和非认知能力的因果关系,以揭示志愿服务参与究竟是筛选还是培育了大学生的非认知能力。研究结果证实了志愿服务参与对外向性和尽责性有筛选作用,对宜人性有培育作用,对情绪稳定性和开放性既没有筛选作用,也没有培育作用。这些结果表明高校志愿服务主要通过人格特质机制筛选了学生的非认知能力,对非认知能力的培育作用有限,促使我们重新审视高校志愿服务如何发挥实践育人的功能。 展开更多
关键词 志愿服务参与 非认知能力 因果关系 双重差分法 追踪调研
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基于病因病机探讨年龄相关性黄斑变性与骨性关节炎的相关性
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作者 李晓宇 高云 +5 位作者 梁丽娜 陈强 郭育卿 张帅 杨胜平 崔玉石 《中国中医眼科杂志》 2024年第3期247-252,共6页
年龄相关性黄斑变性(AMD)与骨性关节炎(OA)均为老年常见慢病,是老年退行性改变在人体不同组织器官的病理表现。最新研究发现AMD与OA发病具有相关性,OA患者发生AMD的风险较高,其机制尚未明确,推测可能与补体系统、细胞因子、炎性细胞、... 年龄相关性黄斑变性(AMD)与骨性关节炎(OA)均为老年常见慢病,是老年退行性改变在人体不同组织器官的病理表现。最新研究发现AMD与OA发病具有相关性,OA患者发生AMD的风险较高,其机制尚未明确,推测可能与补体系统、细胞因子、炎性细胞、自噬及Wnt、Notch、丝裂原活化蛋白激酶(MAPK)等多条信号通路有关。从中医病因病机上讲,AMD与OA虽病位与临床表现不同,但二者均为本虚标实之病,与年老肝、脾、肾亏损有关。本文拟从发病危险因素、中医病因病机、病理及分子生物学方面进行探讨AMD与OA异病中的共病规律,从而为AMD及OA的预防和治疗提供新思路。 展开更多
关键词 病因病机 年龄相关性黄斑变性 骨性关节炎 异病同治
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不同综合评价法对大豆综合农艺性状的分析及比较研究
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作者 昝凯 柴语潼 +3 位作者 陈亚光 牛静 王铭 牛永锋 《天津农业科学》 CAS 2024年第10期8-15,共8页
为科学合理地评价大豆综合农艺性状,采用DTOPSIS法、灰色关联度分析法、模糊评价法、同异分析法和主成分分析法5种常用综合评价法对2020年河南省夏大豆区域试验的14个品种进行综合分析,比较不同方法在大豆农艺性状综合评价方面的优劣。... 为科学合理地评价大豆综合农艺性状,采用DTOPSIS法、灰色关联度分析法、模糊评价法、同异分析法和主成分分析法5种常用综合评价法对2020年河南省夏大豆区域试验的14个品种进行综合分析,比较不同方法在大豆农艺性状综合评价方面的优劣。结果表明:5种分析方法计算出的参试品种综合得分之间存在极显著正相关关系,其中DTOPSIS法对品种综合性状优劣的区分度最好,其次为灰色关联度法、同异分析法、主成分分析法和模糊函数法;同异分析法对综合性状的评价准确度最高,其次为模糊函数法、灰色关联度法、主成分分析和DTOPSIS法;5种分析方法的综合得分与产量的灰色关联度最大的为灰色关联度法,其次为DTOPSIS法、同异分析法、模糊函数法和主成分分析。综上,灰色关联度分析法对大量大豆材料农艺性状的综合评价具有较高的准确度和区分度,并且分析结果与产量联系密切,能够为大豆品系鉴定和筛选提供有效的决策参考。 展开更多
关键词 大豆 灰色关联度分析法 DTOPSIS法 模糊函数法 同异分析法 主成分分析法
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Hard life for sons in the nest?Sex-dependent offspring mortality in Great Tits in urban and forest areas
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作者 Nora Agh Henriett Anna Dalvári +2 位作者 Krisztián Szabó Ivett Pipoly András Liker 《Avian Research》 SCIE CSCD 2024年第1期91-97,共7页
Sex-biased mortality can occur in birds during development,for example due to sexual differences in energy requirement and/or environmental sensitivity,or the effects of sex hormones or sex differences in the expressi... Sex-biased mortality can occur in birds during development,for example due to sexual differences in energy requirement and/or environmental sensitivity,or the effects of sex hormones or sex differences in the expression of mutations linked to sex chromosomes.The extent of sex-bias in mortality may also be related to environmental conditions that influence offspring development and survival.Urban areas often provide poorer conditions for nestling development resulting in higher offspring mortality compared to natural areas,which may accelerate sex differences in offspring mortality in cities.To test this hypothesis,we examined the sex ratio of dead offspring in Great Tits(Parus major),using 427 samples of unhatched eggs and dead nestlings collected in two urban and two forest sites between 2013 and 2019.The ratio of males in the whole sample of dead offspring(56.9%)was significantly higher than expected by an 1:1 ratio,and the strongest sex biases were detected in urban areas(57.6%males)and in young nestlings(<14 days old,59.0%males).However,the sex ratios of dead offspring did not differ significantly among study sites and between offspring developmental stages.29.3%of unhatched eggs contained a visible embryo,and the proportion of embryo-containing unhatched eggs did not differ significantly between urban and forest study sites.These results suggest male-biased offspring mortality in Great Tits,and highlight the need of large datasets to detect subtle differences between habitats and developmental stages. 展开更多
关键词 Great Tit URBANIZATION Nestling mortality Sex related differences
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