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农作物产量预报模型研究与实践   总被引:5,自引:0,他引:5  
选取玉米、大豆、小麦三种作物,建立产量的定性和定量预报模型,即年景趋势预报模型、逐步回归周期分量预报模型和多层递阶预报模型。经过检验和预报实践检验,表明所得到的预测模型具有一定的实用价值。  相似文献   

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The study on the relationship between trace elements and diseases often need to build a classification/regression model. Furthermore, the accuracy of such a model is of particular importance and directly decides its applicability. The goal of this study is to explore the feasibility of applying boosting, i.e., a new strategy from machine learning, to model the relationship between trace elements and diseases. Two examples are employed to illustrate the technique in the applications of classification and regression, respectively. The first example involves the diagnosis of anorexia according to the concentrations of six elements (i.e. classification task). Decision stump and support vector machine are used as the weak/base algorithm and reference algorithm, respectively. The second example involves the prediction of breast cancer mortality based on the intake of trace elements (i.e. a regression task). In this regard, partial least squares is not only used as the weak/base algorithm, but also the reference algorithm. The results from both examples confirm the potential of boosting in modeling the relationship between trace elements and diseases.  相似文献   

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目的 结合手术分级管理要求,初步建立医师手术能力考评体系,通过考评结果了解各临床外系科室的情况。方法 通过文献检索、现场问卷调查及专家咨询等方法,建立以临床操作技能评估(DOPS)为核心的医师手术能力考评体系。该体系包括了DOPS技能评估、非计划再次手术和年内手术量三个方面的考核。运用此体系对医院8个科室129名外科医生进行评估,并对评估结果进行比较。结果 采用t检验提示,外系科室中耳鼻咽喉科、骨科和妇产科高于整体水平(t=2.42、2.18、2.35,P=0.03、0.04、0.02,P<0.05),胸外科、神经外科低于整体水平t=-2.64、-2.63,P=0.02、0.03,P<0.05),眼科、泌尿外科、普外科与整体水平无明显差异(t=0.83、-1.84、-1.17,P=0.43、0.86、0.25,P>0.05)。结论 外科各科室之间的考核结果存在差异,医院需积极关注薄弱科室,根据考核结果强化培训和监督,保证患者医疗安全。

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葡糖杆菌属分类及其主要应用的研究进展   总被引:2,自引:0,他引:2  
葡糖杆菌是醋酸菌科的一个重要属,与人类关系密切,该属中部分菌株在维生素C、米格列醇的工业生产及合成中起着重要作用;此外,该属菌株还能氧化葡萄糖生成葡糖酸盐和酮基葡糖酸等工业重要中间体。综述了葡糖杆菌的研究进展,主要介绍了葡糖杆菌的生理生化特征、分类进展及其主要应用,可以为广大醋酸菌研究者提供参考。  相似文献   

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通过对黑龙江省某三级甲等医院应用病例分型现状的分析,同时按照医院管理年要求,根据地域特点,选取患有高血压、冠心病等疾病的住院患者为研究对象,从病历分型应用的现状出发,对医院整体的业绩进行评价,明确病例分型对医院发展的重要作用,旨在为各医疗机构实施病例分型管理提供借鉴和参考。  相似文献   

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陈敏  郭晓东  聂影  刘阳  王瑞芳  张大鹍 《生物磁学》2012,(28):5473-5475
目的:利用超声造影研究高分化和低分化肝癌患者的肿瘤血流灌注情况,探讨超声造影在肝癌分级的诊断价值。方法:选择我院原发性肝癌(HCC)患者65例并根据活检肝细胞癌病变和肿瘤分级不同分为A组37例(高分化组)和B组28例(低分化组),对两组患者行超声造影检查,分析超声造影的血流灌注状态。结果:A组与B组病灶的到达时间(AT)、峰值时间(TTP)和峰值强度(PI)均存在显著的差异性(tAT=7.266,PAT=0.000;tTTP=5.966,PTTP=0.000;tPI=8.219,PPI=0.000)。A组与B组间的病灶增强时间(1)、增强斜率(2)、清除时间(3)、清除斜率(4)具有差异,并且差异具有统计学意义(t1=7.266,PI=0.000;t2=317,P2=0.000;t3=8.880,P3=0.000;t4=6.178,P4=0.000)。结论:超声造影可作为一种新型的肝癌分级方法,对于早期诊断肝癌和获得肿瘤分级具有很大的临床价值。  相似文献   

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The dynamics of the "Etang de Berre", a brackish lagoon situated close to the French Mediterranean sea coast, is strongly disturbed by freshwater inputs coming from an hydroelectric power station. The system dynamics has been described as a sequence of daily typical states from a set of physicochemical variables such as temperature, salinity and dissolved oxygen rates collected over three years by an automatic sampling station. Each daily pattern summarizes the evolution, hour by hour of the physicochemical variables. This article presents results of forecasts of the states of the system subjected to the simultaneous effects of meteorological conditions and freshwater releases. We recall the main step of the classification tree method used to build up the predictive model (Classification and Regression Trees, Breiman et al., 1984) and we propose a transfer procedure in order to test the stability of the model. Results obtained on the Etang de Berre data set allow us to describe and predict the effects of the environmental variables on the system dynamics with a margin of error. The transfer procedure applied after the tree building process gives a maximum gain in prediction accuracy of about 15%.  相似文献   

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A Newly Revised Classification of the Protozoa*   总被引:1,自引:0,他引:1  
SYNOPSIS The subkingdom Protozoa now includes over 65,000 named species, of which over half are fossil and ~ 10,000 are parasitic. Among living species, this includes ~ 250 parasitic and 11,300 free-living sarcodines (of which ~ 4,600 are foraminiferids); 1.800 parasitic and 5,100 free-living flagellates: ~ 5,600 parasitic “Sporozoa” (including Apicomplexa, Microspora, Myxospora, and Aseetospora); and ~ 2,500 parasitic and 4,700 free-living ciliates. There are undoubtedly thousands more still unmamed. Seven phyla of PROTOZOA are accepted in this classification—SARCOMASTIGOPHORA. LABYRINTHOMORPHA, APICOMPLEXA, MICROSPORA, ASCETOSPORA, MYXOSPORA, and CILIOPHORA. Diagnoses are given for these and for all higher taxa through suborders, and representative genera of each are named. the present scheme is a considerable revision of the Society's 1964 classification, which was prepared at a time when perhaps 48,000 species had been named. It has been necessitated by the acquisition of a great deal of new taxonomic information, much of it through electron microscopy. It is hoped that the present classification incorporates most of the major changes that will be made for some time. and that it will be used for many years by both protozoologists and non-protozoologists.  相似文献   

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病毒感染相关疾病严重威胁人类的健康,目前的抗病毒疗法难以治愈慢性病毒性感染引起的一些疾病,如获得性免疫缺陷综合征和乙型肝炎等,因此迫切需要新的治疗方法。可直接靶向遗传物质的基因编辑技术或将成为对抗病毒的有力工具。作为一种可编程的核酸酶介导的新型基因编辑技术,CRISPR/Cas9系统因其具有编辑效率高、操作简单、成本低、适用范围广等优点,而成功应用于多种人类相关疾病的研究中,也为病毒感染相关疾病的研究以及开发新的治疗方法提供了新的技术手段。主要对CRISPR/Cas9系统的作用机制以及在人类常见的病毒感染相关疾病治疗研究中的最新进展进行综述。  相似文献   

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病毒感染相关疾病严重威胁人类的健康,目前的抗病毒疗法难以治愈慢性病毒性感染引起的一些疾病,如获得性免疫缺陷综合征和乙型肝炎等,因此迫切需要新的治疗方法。可直接靶向遗传物质的基因编辑技术或将成为对抗病毒的有力工具。作为一种可编程的核酸酶介导的新型基因编辑技术,CRISPR/Cas9系统因其具有编辑效率高、操作简单、成本低、适用范围广等优点,而成功应用于多种人类相关疾病的研究中,也为病毒感染相关疾病的研究以及开发新的治疗方法提供了新的技术手段。主要对CRISPR/Cas9系统的作用机制以及在人类常见的病毒感染相关疾病治疗研究中的最新进展进行综述。  相似文献   

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本文从色彩的角度把闽南地区123种常见彩叶植物分为红色、黄色和银色三个系列。红色系列有36种,占29%;黄色系列有45种,占37%;银色系列有42种,占34%。本分类法简单易操作,便于选择与应用。文中还探讨彩叶植物的主要特征及其在园林设计和园林绿化中的应用,并提出合理化建议。  相似文献   

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Using the nearest-neighbour method in the course of numerical classification the four stages of the grazing retrogressive succession .of the Kobresia vegetation in Maqu Xian are divided: Ligularia virgaurea +Stipa aliena -Saussurea sp community and Leontopodium sp-Saussurea superba f. Pygmaea community belongs to the RSS (Retrogressive Succession Stages) of the grazing extremely; Anemone rivularis var fioreminore-Ligularia virgaurea-Kobresia spp community belongs to the RSS of the grazing seriously; Brachy-podium sylvaticum var gracile-Kobresia spp, Kobresia spp-Polygonum viviparum-Festuca rubra and Kobresia spp-Blysmus sinocompressus -Potentilla anserina communities belong to the RSS of the grazing moderately; Kobresia spp-Trollius farrei community belongs to the RSS of the grazing properly. Such classification method gives the same result as the traditional classificational methods of the RSS do. But it gives the numerical bases.  相似文献   

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诱导型一氧化氮合酶与疾病   总被引:4,自引:0,他引:4  
炎症是众多疾病如自体免疫紊乱、神经退行性病变、心血管疾病和癌症发展的病理机制,诱导型一氧化氮合酶在炎症过程中被诱导表达,产生过量的一氧化氮,引发炎症级联反应,进而导致以上多种疾病发生。抑制诱导型一氧化氮合酶表达在体内体外实验及临床使用中均体现抗炎效果和症状改善。本文综述了诱导型一氧化氮合酶在炎症过程中诱导表达及与各类重大疾病联系的最新进展,并展望了诱导型一氧化氮合酶抑制剂作为抗炎治疗策略的前景。  相似文献   

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The application of the grand canonical ensemble in statisticalthermodynamics to the stimulus adsorption on the olfactory receptorsites, assuming some simplifying hypotheses, leads us to anexpression of the olfactory response R, which is a functionof various physico-chemical parameters involved in the olfactionmechanism, e.g. the stimulus concentration, the saturated vaporpressure, the power law exponent and the partition coefficient.This expression of R is in agreement with the olfactory responseof the Hill model, but is more explicit. Stevens' law and theolfactory threshold expression are easily deduced from R. Theexpression of the threshold we established from R enabled usto explain some empirical relations in the literature betweenthe parameters quoted above. The use of the grand canonicalensemble with the chemical potential notion gave us an interpretationof Stevens' law and a better understanding of the role of someparameters involved in the olfaction mechanism, such as saturatedvapor pressure and power law exponent. Chem. Senses 22: 67–75,1997.  相似文献   

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新型数值分类软件X-Cluster的开发及应用   总被引:3,自引:0,他引:3  
针对目前常用数值分类软件的不足,采用多种设计模式开发了新型数值分类软件X-C luster。该软件具有界面友好、操作方便、体积小、速度快、功能强大、应用范围广等特点,能够满足大多数情况下数值分类研究工作的需求,并在芽孢杆菌分类研究中得到了验证。  相似文献   

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