odds ratio在医学动物实验中的应用

目的分析odds ratio在医学动物实验中的应用现状。方法以医学动物实验中常用动物模型及优势比或odds ra-tio为检索式进行搜索,分别对比分析中外数据库中7种动物模型实验中应用odds ratio的状况。同时,给出范例,说明OR值的计算方法及不同结果的实际意义。结果动物模型实验中使用OR值作为统计指标的寥寥无几。结论OR值的重要性在国内没有得到足够的关注。

Collapsibility of odds ratios for a continuous outcome variable

The sign of an association measure between two varibles may be strongly affected and even be reversed after marginalization over a backgruoud variable, which is the well-known Yule-Simpson paradox.Odds ratios are strongly collapsible over a background variable if they remain unchanged no matter how the background variable is partially pooled.In this paper, we firstly give some definitions and notations about odds ratios between a dichotomous explanatory variable and a continuous response variable.Then, we present conditions for simple collapsibility of odds ratios.Further, necessary and sufficient conditions are given for strong collapsibility of odds ratios for continuous outcome variable.

Odds Ratio &Relative Risk Ratio of Buoy Conditions for Storms in the Atlantic Basin

The purpose of this paper is to bring awareness to the general public that certain conditions that occur at a buoy in the Atlantic Basin, such as wind located at the buoy, pressure located at a buoy, water temperature located at a buoy, atmospheric pressure located at a buoy, may be useful in helping predict when a hurricane could possibly hit the state of Florida in the future. One of the goals of this paper is to bring new statistical methods to investigate and analyze data, which will create better predicable measures in determining when a hurricane will possibly hit the state of Florida. In this paper, the topics of binary logistic regression and multinomial regression modeling are discussed in reference to their outcomes of both the odds ratio and relative risk ratio respectively. The coefficients from these models will show which prospective buoy conditions are possibly more responsible for indication of a storm being present in the Atlantic Basin. In this paper, the data that was used and compiled into a larger data set came from two different sources. First, the hurricane data for the years 1992-2013 came from Unisys Weather site (Atlantic Basin Hurricanes data) and the buoy data has been available from the National Buoy Center. In this paper, the variables of interest are: storm present, buoy wind speed, buoy pressure, buoy atmospheric temperature, buoy water temperature and buoy wind direction. The buoy conditions are the buoy wind, the buoy wind direction, the buoy pressure, buoy atmospheric temperature and the buoy water temperature.

Test for Homogeneity of Odds Ratios Using <i>U</i>-Statistics

There are a few statistics testing the homogeneity of odds ratios across strata. Asymptotic statistics lose their power in the “sparse-data” setting. Both asymptotic statistics and exact tests have low power when the sample sizes are small. We created a set of U statistics and compared them with some existing statistics in testing homogeneity of OR at different data settings. We evaluated their performance in terms of the empirical size and power via Monto Carlo simulations. Our results showed that two of the U-statistics under our study had higher power for testing homogeneity of odds ratios for 2 by 2 contingency tables. The application of the tests was illustrated in two real examples.

基于Odds-Matrix算法的中长期电量组合预测方法及其应用

中长期电量的组合预测存在权重选择困难,适应性、抗干扰性较差的问题.文中结合目前广泛应用的组合预测技术,设计了以Odds-Matrix算法为核心的Odds-Matrix组合预测方法.该组合预测方法利用Odds-Matrix算法对单一预测模型的有效性进行定量分析,用权重概率分布函数来描述各个方法的优劣,然后根据权重进行单一预测模型的筛选和组合.利用实际数据对所设计的Odds-Matrix组合预测方法进行测试,结果表明,文中预测方法的精确度较其他常用组合预测法较高,说明该方法具有较强的适应性与抗干扰性.

基于指数分布的比例odds模型次序统计量的随机性质

给出几种常见序关系的定义,在比例odds模型的框架下,当分布函数替换为指数分布时,对其次序统计量作了随机比较.

基于比例odds模型最小次序统计量的随机比较

在比例odds模型的框架下,对它的最小次序统计量作了随机比较,包括似然比序,失效率序和随机序.

基于改进Ratio统计量的重尾AR(p)时间序列均值变点检验

文章提出两个改进的Ratio统计量来研究重尾AR(p)时间序列均值变点检验问题,在原假设下推导了统计量的渐近分布,且在备择假设下证明了其一致性。由于重尾指数未知且难以估计,因此结合Wild Bootstrap重抽样方法来确定渐近分布的临界值;在均值变点存在的情形下,给出了变点位置的一致估计量。数值模拟结果表明:统计量的临界值均不受重尾指数和自回归系数的影响,其经验水平和经验势均取得满意的效果;尤其在原假设下,积分型Ratio统计量的经验水平表现出更好的稳健性,而在备择假设下,最值型Ratio统计量则具备更好的显著性。最后,基于一组股票数据,从实际应用角度进一步阐明所提方法的有效性和可行性。

Filtration Structure of Finite-Dimensional Special Odd Hamiltonian Superalgebras in Prime Characteristic

The filtration structure of finite-dimensional special odd Hamilton superalgebras over a field of prime characteristic was studied. By determining ad-nilpotent dements in the even part, the natural filtration of special odd Hamiltonian superalgebras is proved to be invariant. Using this result, the special odd Hamilton superalgebras is classified. Finally, the automorphism group of the restricted special odd Hamilton superalgebras is determined.

Optimum design of equivalent accelerated life testing plans based on proportional hazards-proportional odds model

The optimum design of equivalent accelerated life testing plan based on proportional hazards-proportional odds model using D-optimality is presented. The defined equivalent test plan is the test plan that has the same value of the determinant of Fisher information matrix. The equivalent test plan of step stress accelerated life testing （SSALT） to a baseline optimum constant stress accelerated life testing （CSALT） plan is obtained by adjusting the censoring time of SSALT and solving the optimization problem for each case to achieve the same value of the determinant of Fisher information matrix as in the baseline optimum CSALT plan. Numer- ical examples are given finally which demonstrate the equivalent SSALT plan to the baseline optimum CSALT plan reduces almost half of the test time while achieving approximately the same estimation errors of model parameters.

Development and validation of prognostic nomogram based on log odds of positive lymph nodes for patients with gastric signet ring cell carcinoma

Objective: Our aims were to establish novel nomogram models, which directly targeted patients with signet ring cell carcinoma(SRC), for individualized prediction of overall survival(OS) rate and cancer-specific survival(CSS).Methods: We selected 1,365 SRC patients diagnosed from 2010 to 2015 from Surveillance, Epidemiology and End Results(SEER) database, and then randomly partitioned them into a training cohort and a validation cohort.Independent predicted indicators, which were identified by using univariate testing and multivariate analyses, were used to construct our prognostic nomogram models. Three methods, Harrell concordance index(C-index), receiver operating characteristics(ROC) curve and calibration curve, were used to assess the ability of discrimination and predictive accuracy. Integrated discrimination improvement(IDI), net reclassification improvement(NRI) and decision curve analysis(DCA) were used to assess clinical utility of our nomogram models.Results: Six independent predicted indicators, age, race, log odds of positive lymph nodes(LODDS), T stage, M stage and tumor size, were associated with OS rate. Nevertheless, only five independent predicted indicators were associated with CSS except race. The developed nomograms based on those independent predicted factors showed reliable discrimination. C-index of our nomogram for OS and CSS was 0.760 and 0.763, which were higher than American Joint Committee on Cancer(AJCC) 8 th edition tumor-node-metastasis(TNM) staging system(0.734 and 0.741, respectively). C-index of validation cohort for OS was 0.757 and for CSS was 0.773. The calibration curves also performed good consistency. IDI, NRI and DCA showed the nomograms for both OS and CSS had a comparable clinical utility than the TNM staging system.Conclusions: The novel nomogram models based on LODDS provided satisfying predictive ability of SRC both in OS and CSS than AJCC 8 th edition TNM staging system alone.

Accelerated proportional degradation hazards-odds model in accelerated degradation test

An accelerated proportional degradation hazards-odds model is proposed. It is a non-parametric model and thus has path- free and distribution-free properties, avoiding the errors caused by faulty assumptions of degradation paths or distribution of degra- dation measurements. It is established based on a link function which combines the degradation cumulative hazard rate function and the degradation odds function through a transformation pa- rameter, and this makes the accelerated proportional degradation hazards model and the accelerated proportional degradation odds model special cases of it. Hypothesis tests are discussed, and the proposed model is applicable when some model assumptions are satisfied. This model is utilized to estimate the reliability of minia- ture bulbs under low stress levels based on the degradation data obtained under high stress levels to validate the effectiveness of this model.

odds比模型的简单介绍

ｏｄｄｓ比模型因其简单明了而在实践中很有用，本文利用医学上的例子着重说明了其应用。

Log odds of positive lymph nodes is a better prognostic factor for oesophageal signet ring cell carcinoma than N stage

BACKGROUND Signet ring cell carcinoma is a rare type of oesophageal cancer,and we hypothesized that log odds of positive lymph nodes(LODDS)is a better prognostic factor for oesophageal signet ring cell carcinoma.AIM To explore a novel prognostic factor for oesophageal signet ring cell carcinoma by comparing two lymph node-related prognostic factors,log odds of positive LODDS and N stage.METHODS A total of 259 cases of oesophageal signet ring cell carcinoma after oesophagectomy were obtained from the Surveillance,Epidemiology,and End Results database between 2006 and 2016.The prognostic value of LODDS and N stage for oesophageal signet ring cell carcinoma was evaluated by univariate and multivariate analyses.The Akaike information criterion and Harrell’s C-index were used to assess the value of two prediction models based on lymph nodes.External validation was performed to further confirm the conclusion.RESULTS The 5-year cancer-specific survival(CSS)and 5-year overall survival(OS)rates of all the cases were 41.3%and 27.0%,respectively.The Kaplan-Meier method showed that LODDS had a higher score of log rank chi-squared(OS:46.162,CSS:41.178)than N stage(OS:36.215,CSS:31.583).Univariate analyses showed that insurance,race,T stage,M stage,TNM stage,radiation therapy,N stage,and LODDS were potential prognostic factors for OS(P<0.1).The multivariate Cox regression model showed that LODDS was an significant independent prognostic factor for oesophageal signet ring carcinoma patients after surgical resection(P<0.05),while N stage was not considered to be a significant prognostic factor(P=0.122).Model 2(LODDS)had a higher degree of discrimination and fit than Model 1(N stage)(LODDS vs N stage,Harell’s C-index 0.673 vs 0.656,P<0.001;Akaike information criterion 1688.824 vs 1697.519,P<0.001).The results of external validation were consistent with those in the study cohort.CONCLUSION LODDS is a superior prognostic factor to N stage for patients with oesophageal signet ring cell carcinoma after oesophagectomy.

Advantage of log odds of positive lymph nodes in prognostic evaluation of patients with early-onset colon cancer

BACKGROUND Colon cancer(CC)is one of the most common cancers of the digestive tract,the third most common cancer worldwide,and the second most common cause of cancer-related deaths.Previous studies have demonstrated a higher risk of lymph node metastasis(LNM)in young patients with CC.It might be reasonable to treat patients with early-onset locally advanced CC with extended lymph node dissection.However,few studies have focused on early-onset CC(ECC)patients with LNM.At present,the methods of predicting and evaluating the prognosis of ECC patients with LNM are controversial.From the data of patients with CC obtained from the Surveillance,Epidemiology,and End Results(SEER)database,data of young patients with ECC(≤50 years old)was screened.Patients with unknown data were excluded from the study,while the remaining patients were included.The patients were randomly divided into a training group(train)and a testing group(test)in the ratio of 7:3,while building the model.The model was constructed by the training group and verified by the testing group.Using multiple Cox regression models to compare the prediction efficiency of LNM indicators,nomograms were built based on the best model selected for overall survival(OS)and cause-specific survival(CSS).In the two groups,the performance of the nomogram was evaluated by constructing a calibration plot,time-dependent area under the curve(AUC),and decision curve analysis.Finally,the patients were grouped based on the risk score predicted by the prognosis model,and the survival curve was constructed after comparing the survival status of the high and low-risk groups.RESULTS Records of 26922 ECC patients were screened from the SEER database.N classification,positive lymph nodes(PLN),lymph node ratio(LNR)and log odds of PLN(LODDS)were considered to be independent predictors of OS and CSS.In addition,independent risk factors for OS included gender,race,marital status,primary site,histology,grade,T,and M classification,while the independent prognostic factors for CSS included race,marital status,primary site,grade,T,and M classification.The prediction model including LODDS is composed of minimal Akaike information criterion,maximal concordance indexes,and AUCs.Factors including gender,race,marital status,primary site,histology,grade,T,M classification,and LODDS were integrated into the OS nomogram,while race,marital status,primary site,grade,T,M classification,and LODDS were included into the CSS nomogram.The nomogram representing both cohorts had been successfully verified in terms of prediction accuracy and clinical practicability.CONCLUSION LODDS is superior to N-stage,PLN,and LNR of ECC.The nomogram containing LODDS might be helpful in tumor evaluation and clinical decision-making,since it provides an appropriate prediction of ECC.

Theoretical study of the odd-even-order harmonic generation for asymmetric ions in non-Born-Oppenheimer approximation

We calculated the harmonic spectra generated from the asymmetric molecules of HD^＋ and HeH^2＋. It is found that HD＋produces only odd harmonics, while HeH^2＋produces both odd and even harmonics. Further analysis reveals that for both HD^＋ and HeH^2＋, the nuclear dipole acceleration can generate even harmonics, but it is three orders of magnitude lower than that of the electron. Hence, the electronic dipole acceleration dominates the harmonic generation. For HD^＋,the electronic dipole acceleration only contributes to the generation of odd harmonics, but for HeH^2＋it contributes to the generation of both odd and even harmonics. Besides, one concept of the broken degree of system-symmetry is proposed to explain the different odd-even property between the harmonic spectra of HD^＋ and HeH^2＋.

阳性淋巴结对数比(LODDS)对食管鳞癌左胸入路根治术后pN_(0)期患者预后的预测价值

目的:探讨阳性淋巴结对数比(LODDS)对食管鳞癌左胸入路根治术后pN_(0)期患者预后的预测价值。方法:回顾性分析2005年01月至2014年12月期间在我院胸外科行左胸入路的食管癌根治术,且术后病理类型为鳞癌,病理分期为N_(0)期的336例患者的临床、病理及随访资料,分析LODDS对该组患者预后的影响及其判断预后的最佳截点值,应用SPSS 19.0软件进行统计学分析。结果:ROC曲线分析显示,当LODDS以-1.278为最佳截点值时,其约登指数最大,预测患者预后效果最好。将全组患者的LODDS值以-1.278分为≤-1.278组和>-1.278组,两组患者1、3、5年生存率分别为92.3%、82.1%、75.0%和86.1%、62.6%、52.6%,差异有显著性(χ^(2)=19.241,P=0.000)。全组患者1、3、5年生存率分别为89.5%、71.7%和63.0%。COX多因素分析结果显示,患者年龄、pT分期和LODDS为影响其生存的独立性因素。结论:本研究结果显示,LODDS为胸段食管鳞癌左胸入路根治术后pN_(0)期患者预后的独立性影响因素,且LODDS≤-1.278的患者具有较好的预后。本研究结果尚需多中心、大样本的临床研究进一步证实。

Yields,growth and water use under chemical topping in relations to row configuration and plant density in drip-irrigated cotton

Background Water deficit is an important problem in agricultural production in arid regions.With the advent of wholly mechanized technology for cotton planting in Xinjiang,it is important to determine which planting mode could achieve high yield,fiber quality and water use efficiency(WUE).This study aimed to explore if chemical topping affected cotton yield,quality and water use in relation to row configuration and plant densities.Results Experiments were carried out in Xinjiang China,in 2020 and 2021 with two topping method,manual topping and chemical topping,two plant densities,low and high,and two row configurations,i.e.,76 cm equal rows and 10+66 cm narrow-wide rows,which were commonly applied in matching harvest machine.Chemical topping increased seed cotton yield,but did not affect cotton fiber quality comparing to traditional manual topping.Under equal row spacing,the WUE in higher density was 62.4%higher than in the lower one.However,under narrow-wide row spacing,the WUE in lower density was 53.3%higher than in higher one(farmers’practice).For machine-harvest cotton in Xinjiang,the optimal row configuration and plant density for chemical topping was narrow-wide rows with 15 plants m-2 or equal rows with 18 plants m-2.Conclusion The plant density recommended in narrow-wide rows was less than farmers’practice and the density in equal rows was moderate with local practice.Our results provide new knowledge on optimizing agronomic managements of machine-harvested cotton for both high yield and water efficient.

Combining lymph node ratio to develop prognostic models for postoperative gastric neuroendocrine neoplasm patients

BACKGROUND Lymph node ratio(LNR)was demonstrated to play a crucial role in the prognosis of many tumors.However,research concerning the prognostic value of LNR in postoperative gastric neuroendocrine neoplasm(NEN)patients was limited.AIM To explore the prognostic value of LNR in postoperative gastric NEN patients and to combine LNR to develop prognostic models.METHODS A total of 286 patients from the Surveillance,Epidemiology,and End Results database were divided into the training set and validation set at a ratio of 8:2.92 patients from the First Affiliated Hospital of Soochow University in China were designated as a test set.Cox regression analysis was used to explore the relationship between LNR and disease-specific survival(DSS)of gastric NEN patients.Random survival forest(RSF)algorithm and Cox proportional hazards(CoxPH)analysis were applied to develop models to predict DSS respectively,and compared with the 8th edition American Joint Committee on Cancer(AJCC)tumornode-metastasis(TNM)staging.RESULTS Multivariate analyses indicated that LNR was an independent prognostic factor for postoperative gastric NEN patients and a higher LNR was accompanied by a higher risk of death.The RSF model exhibited the best performance in predicting DSS,with the C-index in the test set being 0.769[95%confidence interval(CI):0.691-0.846]outperforming the CoxPH model(0.744,95%CI:0.665-0.822)and the 8th edition AJCC TNM staging(0.723,95%CI:0.613-0.833).The calibration curves and decision curve analysis(DCA)demonstrated the RSF model had good calibration and clinical benefits.Furthermore,the RSF model could perform risk stratification and individual prognosis prediction effectively.CONCLUSION A higher LNR indicated a lower DSS in postoperative gastric NEN patients.The RSF model outperformed the CoxPH model and the 8th edition AJCC TNM staging in the test set,showing potential in clinical practice.