Mathematical Population Studies最新文献

英文中文

Robust estimation of the population mean using quantile regression under systematic sampling 系统抽样下使用分位数回归对总体均值的稳健估计

IF 1.8 3区社会学 Q3 DEMOGRAPHY

Mathematical Population Studies

Pub Date : 2022-12-05 DOI: 10.1080/08898480.2022.2139072

U. Shahzad, I. Ahmad, N. Al-Noor, M. Hanif, I. Almanjahie

ABSTRACT Regression ratio mean estimators of a study variable are defined as the coefficients provided by the ordinary least-squares regression of on a given auxiliary variable . They can be improved by using the coefficient of variation and the coefficient of kurtosis of . The influence of outliers on the estimates of the population mean of is neutralized by calculating robust regression coefficients, obtained by the method of either least absolute deviations, Huber-M, Huber-MM, Hampel-M, Tukey-M, or adjusted least squares. These robust coefficients are used to estimate the population mean of under simple random sampling. Extension to systematic sampling—which is a probability sampling in which every element of the population has equal probability of inclusion to be drawn—using the coefficients provided by quantile regression—whose coefficients result from the minimization of the sum of absolute deviations rather than from the square deviations from the regression line—requires ratio estimators of the population mean of . The mean square errors of these estimators are expressed analytically. If the quantile regression coefficient is greater than the ratio of the covariance between the study and the auxiliary variables to the variance of the auxiliary variable minus a function of the mean or the coefficient of variation, skewness, or kurtosis of and , then the proposed robust quantile regression mean estimator of is more efficient than the ratio estimators in the presence of outliers under systematic sampling. The reason is that these estimators only use regression coefficients and not the ratio between the population mean and sample means of the auxiliary variable . The aforementioned condition occurs with the values of the case study. For empirical data of 176 forest strips, the proposed estimate of the volume of timber is over 30% more efficient than the ratio estimates based on quantile regression coefficients.

研究变量的回归比均值估计量定义为给定辅助变量的普通最小二乘回归所提供的系数。它们可以通过使用的变异系数和峰度系数来改进。通过计算稳健回归系数来抵消异常值对总体平均值估计的影响，稳健回归系数通过最小绝对偏差、Huber-M、Huber-MM、Hampel-M、Tukey-M或调整后的最小二乘法获得。这些稳健系数用于估计简单随机抽样下的总体平均值。系统抽样是一种概率抽样，其中群体的每个元素都有相等的被包含概率，使用分位数回归提供的系数，其系数来自绝对偏差之和的最小化，而不是回归线的平方偏差人口平均数。这些估计量的均方误差用解析方法表示。如果分位数回归系数大于研究和辅助变量之间的协方差与辅助变量的方差之比减去和的平均值或变异系数、偏度或峰度的函数，则在系统抽样条件下，所提出的稳健分位数回归均值估计比存在异常值的比率估计更有效。原因是这些估计量只使用回归系数，而不是辅助变量的总体平均值和样本平均值之间的比率。上述情况发生在案例研究的值中。对于176个林带的经验数据，所提出的木材体积估计比基于分位数回归系数的比率估计有效30%以上。

{"title":"Robust estimation of the population mean using quantile regression under systematic sampling","authors":"U. Shahzad, I. Ahmad, N. Al-Noor, M. Hanif, I. Almanjahie","doi":"10.1080/08898480.2022.2139072","DOIUrl":"https://doi.org/10.1080/08898480.2022.2139072","url":null,"abstract":"ABSTRACT Regression ratio mean estimators of a study variable are defined as the coefficients provided by the ordinary least-squares regression of on a given auxiliary variable . They can be improved by using the coefficient of variation and the coefficient of kurtosis of . The influence of outliers on the estimates of the population mean of is neutralized by calculating robust regression coefficients, obtained by the method of either least absolute deviations, Huber-M, Huber-MM, Hampel-M, Tukey-M, or adjusted least squares. These robust coefficients are used to estimate the population mean of under simple random sampling. Extension to systematic sampling—which is a probability sampling in which every element of the population has equal probability of inclusion to be drawn—using the coefficients provided by quantile regression—whose coefficients result from the minimization of the sum of absolute deviations rather than from the square deviations from the regression line—requires ratio estimators of the population mean of . The mean square errors of these estimators are expressed analytically. If the quantile regression coefficient is greater than the ratio of the covariance between the study and the auxiliary variables to the variance of the auxiliary variable minus a function of the mean or the coefficient of variation, skewness, or kurtosis of and , then the proposed robust quantile regression mean estimator of is more efficient than the ratio estimators in the presence of outliers under systematic sampling. The reason is that these estimators only use regression coefficients and not the ratio between the population mean and sample means of the auxiliary variable . The aforementioned condition occurs with the values of the case study. For empirical data of 176 forest strips, the proposed estimate of the volume of timber is over 30% more efficient than the ratio estimates based on quantile regression coefficients.","PeriodicalId":49859,"journal":{"name":"Mathematical Population Studies","volume":"30 1","pages":"195 - 207"},"PeriodicalIF":1.8,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48451618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Parameter estimation for the Moore-Bilikam distribution under progressive type-II censoring, with application to failure times Moore-Bilikam分布在渐进II型截尾下的参数估计及其在故障次数中的应用

IF 1.8 3区社会学 Q3 DEMOGRAPHY

Mathematical Population Studies

Pub Date : 2022-12-05 DOI: 10.1080/08898480.2022.2133850

Mehdi Bazyar, E. Deiri, E. Jamkhaneh

ABSTRACT The Moore-Bilikam distribution is convenient for survival analysis. The estimation of its parameters and its reliability function is performed by maximum likelihood, expectation-maximization, stochastic expectation-maximization, and the Bayesian method. The data are progressively censored of type II (samples are removed randomly from the experiment). Simulation shows that the expectation-maximization estimator of the parameter and the Bayesian-shrinkage estimator of the reliability function are the most efficient (with the minimum mean square error) when they are based on the Weibull and the Pareto distributions, which are specific cases of the Moore-Bilikam distribution. Bayesian and maximum likelihood estimations using the Moore-Bilikam distribution under type-II progressive censoring allow for fitting empirical failure times of an insulating fluid between two electrodes and the resistance of single carbon fibers. The associated reliability functions are estimated by each method.

Moore-Bilikam分布便于生存分析。其参数及其可靠性函数的估计采用最大似然、期望最大化、随机期望最大化和贝叶斯方法。对II型数据进行逐步审查（从实验中随机移除样本）。仿真表明，当参数的期望最大化估计器和可靠性函数的贝叶斯收缩估计器基于Weibull和Pareto分布时，它们是最有效的（具有最小均方误差），这是Moore-Bilkam分布的具体情况。在II型渐进截尾下，使用Moore-Bilikam分布的贝叶斯和最大似然估计允许拟合两个电极之间的绝缘流体的经验失效时间和单个碳纤维的电阻。通过每种方法来估计相关的可靠性函数。

引用次数: 1

Bias and mean square error reduction by changing the shape of the distribution of an auxiliary variable: application to air pollution data in Nan, Thailand 通过改变辅助变量的分布形状来减少偏差和均方误差:应用于泰国南的空气污染数据

IF 1.8 3区社会学 Q3 DEMOGRAPHY

Mathematical Population Studies

Pub Date : 2022-12-05 DOI: 10.1080/08898480.2022.2145790

Natthapat Thongsak, Nuanpan Lawson

ABSTRACT The proposed estimator of the population mean is based on a modification of the shape of the distribution of an auxiliary variable. If the theoretical correlation between the study and the auxiliary variables is less than a term that is proportional to the coefficient of variation of the auxiliary variable divided by the coefficient of variation of the study variable, then the modification of the distribution of the auxiliary variable reduces the bias and the mean square error of the estimator. A simulation confirms the analytical results. Application to air pollution data in Nan, Thailand, shows that on average, the biases of the estimators based on the modified auxiliary variable are reduced by 70% to 98% and the mean square errors by 91% to 100% compared to the estimators based on the unmodified auxiliary variable.

提出的总体均值估计量是基于对辅助变量分布形状的修改。如果研究与辅助变量之间的理论相关性小于与辅助变量的变异系数除以研究变量的变异系数成正比的一项，则对辅助变量分布的修改可以减小估计器的偏置和均方误差。仿真验证了分析结果。对泰国南空气污染数据的应用表明，平均而言，与基于未修改辅助变量的估计器相比，基于修改辅助变量的估计器的偏差减少了70%至98%，均方误差减少了91%至100%。

引用次数: 2

Branching random walk in a random time-independent environment 随机时间无关环境下的分支随机漫步

IF 1.8 3区社会学 Q3 DEMOGRAPHY

Mathematical Population Studies

Pub Date : 2022-12-02 DOI: 10.1080/08898480.2022.2140561

E. Chernousova, O. Hryniv, S. Molchanov

ABSTRACT In a lattice population model, particles move randomly from one site to another as independent random walks, split into two offspring, or die. If duplication and mortality rates are equal and take the same value over all lattice sites, the resulting model is a critical branching random walk (characterized by a mean total number of offspring equal to ). There exists an asymptotical statistical equilibrium, also called steady state. In contrast, when duplication and mortality rates take independent random values drawn from a common nondegenerate distribution (so that the difference between duplication and mortality rates has nonzero variance), then the steady state no longer exists. Simultaneously, at all lattice sites, if the difference between duplication and mortality rates takes strictly positive values with strictly positive probability, the total number of particles grows exponentially. The lattice includes large connected sets where the duplication rate exceeds the mortality rate by a positive constant amount, and these connected sets provide the growth of the total population. This is the supercritical regime of branching processes. On the other hand, if the difference between duplication and mortality rates is almost surely negative or null except when it is almost surely zero, then the total number of particles vanishes asymptotically. The steady state can be reached only if the difference between duplication and mortality rates is almost surely zero.

在晶格种群模型中，粒子以独立随机游动的方式从一个位置随机移动到另一个位置，分裂成两个子代，或者死亡。如果复制率和死亡率相等，并且在所有格点上取相同的值，则得到的模型是一个临界分支随机漫步(其特征是后代的平均总数等于)。存在一个渐近统计平衡，也称为稳态。相反，当复制率和死亡率从一个共同的非退化分布中取独立的随机值时(因此复制率和死亡率之间的差异具有非零方差)，则稳态不再存在。同时，在所有点阵位置，如果复制率和死亡率之差取严格正值，且概率为严格正，则粒子总数呈指数增长。晶格包括复制率超过死亡率一个正常数的大连接集，这些连接集提供了总体的增长。这就是分支过程的超临界状态。另一方面，如果复制率和死亡率之间的差异几乎肯定为负或为零，除非它几乎肯定为零，那么粒子总数就会逐渐消失。只有当复制率和死亡率之间的差异几乎肯定为零时，才能达到稳定状态。

{"title":"Branching random walk in a random time-independent environment","authors":"E. Chernousova, O. Hryniv, S. Molchanov","doi":"10.1080/08898480.2022.2140561","DOIUrl":"https://doi.org/10.1080/08898480.2022.2140561","url":null,"abstract":"ABSTRACT In a lattice population model, particles move randomly from one site to another as independent random walks, split into two offspring, or die. If duplication and mortality rates are equal and take the same value over all lattice sites, the resulting model is a critical branching random walk (characterized by a mean total number of offspring equal to ). There exists an asymptotical statistical equilibrium, also called steady state. In contrast, when duplication and mortality rates take independent random values drawn from a common nondegenerate distribution (so that the difference between duplication and mortality rates has nonzero variance), then the steady state no longer exists. Simultaneously, at all lattice sites, if the difference between duplication and mortality rates takes strictly positive values with strictly positive probability, the total number of particles grows exponentially. The lattice includes large connected sets where the duplication rate exceeds the mortality rate by a positive constant amount, and these connected sets provide the growth of the total population. This is the supercritical regime of branching processes. On the other hand, if the difference between duplication and mortality rates is almost surely negative or null except when it is almost surely zero, then the total number of particles vanishes asymptotically. The steady state can be reached only if the difference between duplication and mortality rates is almost surely zero.","PeriodicalId":49859,"journal":{"name":"Mathematical Population Studies","volume":"30 1","pages":"73 - 94"},"PeriodicalIF":1.8,"publicationDate":"2022-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44396689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The nuclear transportation of PD-L1 and the function in tumor immunity and progression. PD-L1 的核运输及其在肿瘤免疫和进展中的功能。

IF 5.8 3区社会学 Q3 DEMOGRAPHY

Mathematical Population Studies

Pub Date : 2022-10-01 Epub Date: 2022-03-05 DOI: 10.1007/s00262-022-03176-7

Liyan Qu, Jiakang Jin, Jianan Lou, Chao Qian, Jinti Lin, Ankai Xu, Bing Liu, Man Zhang, Huimin Tao, Wei Yu

As the main immune checkpoint, PD-L1-PD-1 interaction plays a critical role in the dysregulation of effector T cells, which contributes to the failure of Chimeric Antigen Receptor T-cell (CAR-T) and other immunotherapies. Presently, most research focuses on the extracellular function of PD-L1. Membrane PD-L1 can interact with its receptor PD-1 and decrease T cell-induced cancer immunity. However, the function of PD-L1 in cancer cells is still unclear. Recent studies have shown the separated clinical significance of PD-L1 expression in various cancer types, showing the complexity of PD-L1 in cancer cell regulation. As a novel regulatory pathway, the nuclear translocation of PD-L1 in cancer cells receives more attention. Results of these preclinical studies demonstrated that nuclear PD-L1 has an essential role in cancer development and other immune checkpoint molecules transcription. Herein, we summarized the mechanisms involved in PD-L1 nuclear transportation and identify the key regulatory factors in this process. Furthermore, we also summarize the function of nuclear PD-L1 in cancer immunity. These findings suggested the novel PD-L1 regulation in cancer development, which showed that nuclear PD-L1 is a potential therapeutic target in future cancer therapy.

作为主要的免疫检查点，PD-L1-PD-1相互作用在效应T细胞失调中起着关键作用，而效应T细胞失调是嵌合抗原受体T细胞（CAR-T）和其他免疫疗法失败的原因之一。目前，大多数研究都集中在 PD-L1 的细胞外功能上。膜 PD-L1 可与其受体 PD-1 相互作用，降低 T 细胞诱导的癌症免疫力。然而，PD-L1 在癌细胞中的功能仍不清楚。最近的研究表明，PD-L1 在不同癌症类型中的表达具有不同的临床意义，显示了 PD-L1 在癌细胞调控中的复杂性。作为一种新的调控途径，PD-L1 在癌细胞中的核转位受到更多关注。这些临床前研究结果表明，核 PD-L1 在癌症发展和其他免疫检查点分子转录中具有重要作用。在此，我们总结了 PD-L1 核转运的相关机制，并确定了这一过程中的关键调控因子。此外，我们还总结了核 PD-L1 在癌症免疫中的功能。这些发现提出了 PD-L1 在癌症发生发展中的新型调控机制，表明核 PD-L1 是未来癌症治疗的潜在靶点。

{"title":"The nuclear transportation of PD-L1 and the function in tumor immunity and progression.","authors":"Liyan Qu, Jiakang Jin, Jianan Lou, Chao Qian, Jinti Lin, Ankai Xu, Bing Liu, Man Zhang, Huimin Tao, Wei Yu","doi":"10.1007/s00262-022-03176-7","DOIUrl":"10.1007/s00262-022-03176-7","url":null,"abstract":"<p><p>As the main immune checkpoint, PD-L1-PD-1 interaction plays a critical role in the dysregulation of effector T cells, which contributes to the failure of Chimeric Antigen Receptor T-cell (CAR-T) and other immunotherapies. Presently, most research focuses on the extracellular function of PD-L1. Membrane PD-L1 can interact with its receptor PD-1 and decrease T cell-induced cancer immunity. However, the function of PD-L1 in cancer cells is still unclear. Recent studies have shown the separated clinical significance of PD-L1 expression in various cancer types, showing the complexity of PD-L1 in cancer cell regulation. As a novel regulatory pathway, the nuclear translocation of PD-L1 in cancer cells receives more attention. Results of these preclinical studies demonstrated that nuclear PD-L1 has an essential role in cancer development and other immune checkpoint molecules transcription. Herein, we summarized the mechanisms involved in PD-L1 nuclear transportation and identify the key regulatory factors in this process. Furthermore, we also summarize the function of nuclear PD-L1 in cancer immunity. These findings suggested the novel PD-L1 regulation in cancer development, which showed that nuclear PD-L1 is a potential therapeutic target in future cancer therapy.</p>","PeriodicalId":49859,"journal":{"name":"Mathematical Population Studies","volume":"22 1","pages":"2313-2323"},"PeriodicalIF":5.8,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10992355/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82056344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Determining the sample size of a post-enumeration survey: The case of China, 2020 抽样后调查样本量的确定:以2020年中国为例

IF 1.8 3区社会学 Q3 DEMOGRAPHY

Mathematical Population Studies

Pub Date : 2022-06-13 DOI: 10.1080/08898480.2022.2075166

Guihua Hu, Ting Wen, Yuhuan Liu

ABSTRACT Post-enumeration surveys are used to assess the quality of censuses. To set up such a survey, the size of the sample to be surveyed must be determined. If the sample design requires several strata, the design effect, which is the ratio of the variance of the two-source estimator to the variance of the single-source estimator for a given sample size, allows an indirect calculation. Another method is to use the sampling variance formula for a given sample size. The sample must have a sufficient total number of geographic subdivisions that are too small. A complete calculation of the sample size is implemented on an example from the 2020 Chinese post-enumeration survey.

摘要点算后调查用于评估人口普查的质量。要进行此类调查，必须确定待调查样本的大小。如果样本设计需要几个层次，则设计效果（即给定样本量下两个源估计器的方差与单个源估计员的方差的比率）允许进行间接计算。另一种方法是对给定的样本量使用抽样方差公式。样本必须有足够的地理分区总数，这些分区太小。以2020年中国人口统计后调查为例，对样本量进行了完整计算。

引用次数: 1

Positive piecewise continuous quasi-periodic solutions to logistic impulsive differential equations logistic脉冲微分方程的正分段连续拟周期解

IF 1.8 3区社会学 Q3 DEMOGRAPHY

Mathematical Population Studies

Pub Date : 2022-05-09 DOI: 10.1080/08898480.2022.2043067

Liangping Qi, Guowei Zong

ABSTRACT To prove the existence of piecewise continuous solutions to a logistic quasi-periodic differential system with impulses (whose coefficients have rationally independent periods), this system is divided into a differential equation and a difference equation. The quasi-periodicity of a function is proved by showing that this function is the uniform limit of a series of trigonometric polynomials with a finite total number of frequencies. The asymptotically stable quasi-periodic positive and piecewise continuous solution is proved to exist and to be unique. Quasi-periodic variation of the environment leads to a quasi-periodic growth of the population size in the sense that the rationally independent frequencies of the system are also frequencies of the quasi-periodic solution. The positive solutions have a repeated behavior similar to that of the quasi-periodic solution for a sufficiently long time due to asymptotical stability. The separation of the continuous-discrete system into a differential equation and a difference equation is a method of proving the existence of a quasi-periodic solution with perturbed coefficients of the impulsive system.

摘要为了证明具有脉冲（其系数具有合理独立周期）的逻辑拟周期微分系统的分段连续解的存在性，将该系统分为微分方程和差分方程。证明了一个函数的拟周期性，证明了该函数是一系列频率总数有限的三角多项式的一致极限。证明了渐近稳定的拟周期正分段连续解的存在性和唯一性。环境的准周期变化导致种群规模的准周期增长，因为系统的合理独立频率也是准周期解的频率。由于渐近稳定性，正解在足够长的时间内具有类似于拟周期解的重复行为。将连续离散系统分离为微分方程和差分方程是证明脉冲系统具有扰动系数的拟周期解存在的一种方法。

{"title":"Positive piecewise continuous quasi-periodic solutions to logistic impulsive differential equations","authors":"Liangping Qi, Guowei Zong","doi":"10.1080/08898480.2022.2043067","DOIUrl":"https://doi.org/10.1080/08898480.2022.2043067","url":null,"abstract":"ABSTRACT To prove the existence of piecewise continuous solutions to a logistic quasi-periodic differential system with impulses (whose coefficients have rationally independent periods), this system is divided into a differential equation and a difference equation. The quasi-periodicity of a function is proved by showing that this function is the uniform limit of a series of trigonometric polynomials with a finite total number of frequencies. The asymptotically stable quasi-periodic positive and piecewise continuous solution is proved to exist and to be unique. Quasi-periodic variation of the environment leads to a quasi-periodic growth of the population size in the sense that the rationally independent frequencies of the system are also frequencies of the quasi-periodic solution. The positive solutions have a repeated behavior similar to that of the quasi-periodic solution for a sufficiently long time due to asymptotical stability. The separation of the continuous-discrete system into a differential equation and a difference equation is a method of proving the existence of a quasi-periodic solution with perturbed coefficients of the impulsive system.","PeriodicalId":49859,"journal":{"name":"Mathematical Population Studies","volume":"30 1","pages":"95 - 121"},"PeriodicalIF":1.8,"publicationDate":"2022-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44933773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multivariate ratio exponential estimators of the population mean under stratified double sampling 分层双抽样下总体均值的多变量比率指数估计

IF 1.8 3区社会学 Q3 DEMOGRAPHY

Mathematical Population Studies

Pub Date : 2022-05-06 DOI: 10.1080/08898480.2022.2055870

Siraj Muneer, A. Khalil, J. Shabbir

ABSTRACT To estimate the population mean when sampling a heterogeneous population and in the absence of a priori information on auxiliary variables, exponential-ratio multivariate estimators are associated under double stratified sampling with two auxiliary variables. Their biases and mean square errors are expressed and simulated. These mean square errors are smaller (the efficiencies are higher) than those of the sample mean estimator and those of other ratio estimators when the correlation between the study and the auxiliary variables exceeds 0.1 in absolute value. In particular, the proposed estimators are more efficient for low correlations between the study and the auxiliary variables. The gain in efficiency reaches a factor of 230.4% on an empirical dataset where the study variable is weakly correlated with each of the two auxiliary variables, and 182.1% on another empirical dataset where it is strongly correlated.

摘要为了估计在没有辅助变量先验信息的情况下对异质总体进行抽样时的总体均值，在具有两个辅助变量的双层抽样下，将指数比多变量估计量相关联。表达并模拟了它们的偏差和均方误差。当研究和辅助变量之间的相关性绝对值超过0.1时，这些均方误差比样本均值估计器和其他比率估计器的均方误差更小（效率更高）。特别是，对于研究和辅助变量之间的低相关性，所提出的估计量更有效。在研究变量与两个辅助变量中的每一个都弱相关的经验数据集上，效率的提高达到了230.4%，在另一个强相关的实验数据集上达到了182.1%。

引用次数: 0

Reduced oviposition period promotes blowfly population extinction in Nicholson’s model Nicholson模型中产卵期的缩短促进了蝇类种群的灭绝

IF 1.8 3区社会学 Q3 DEMOGRAPHY

Mathematical Population Studies

Pub Date : 2022-05-04 DOI: 10.1080/08898480.2022.2051367

I. Elbaz

ABSTRACT Blowflies use open wounds or the accumulation of feces or urine in wool to lay their eggs. The larvae that emerge cause lesions in the host sheep, which can lead to death. They are found in Australia, New Zealand, and the United Kingdom. Nicholson’s model describes the population dynamics of the Australian blowfly (Lucilia Cuprina). It incorporates environmental variation. The extinction of these flies depends on the time to oviposition and the time between generations. The Lyapunov function, which is positive with a negative derivative, provides the condition for the stability of the equilibrium point: the oviposition period must be sufficiently short, because the shorter it is, the more it favors the extinction of the species. The zero solution is the only equilibrium point, synonymous with the extinction of the population. Another species of blowfly, Lucilia Sericata, also attacks sheep in Australia. Both blowflies are ectoparasites of warm-blooded vertebrates, particularly domestic sheep. These two blowflies are related to share same mitochondrial DNA sequences, although the two species are distinct. Presumably to avoid competition between them. the egg-laying time of each species does not occur at the same time of year: L. Sericata prefers warmer months, thus in summer, while L. Cuprina is mainly active in autumn. Laying of eggs in different months allows avoiding competition between these species. This also binds them together. A sufficiently small egg-laying delay then leads to the rapid extinction of both blowfly populations, provided they do not adapt.

摘要：果蝇利用开放性伤口或粪便或尿液在羊毛中积聚来产卵。出现的幼虫会对宿主绵羊造成损伤，从而导致死亡。它们分布在澳大利亚、新西兰和英国。尼科尔森的模型描述了澳大利亚飞蝇（Lucilia Cuplina）的种群动态。它包含了环境变化。这些苍蝇的灭绝取决于产卵的时间和世代之间的时间。李亚普诺夫函数是正的，具有负导数，它为平衡点的稳定性提供了条件：产卵期必须足够短，因为它越短，就越有利于物种的灭绝。零解是唯一的平衡点，与种群灭绝同义。另一种飞蝇Lucilia Sericata也攻击澳大利亚的绵羊。这两种蝇都是温血脊椎动物的体外寄生虫，尤其是家养绵羊。尽管这两个物种不同，但这两种果蝇的线粒体DNA序列相同。大概是为了避免他们之间的竞争。每个物种的产卵时间都不在一年中的同一时间：丝蚕喜欢温暖的月份，因此在夏天，而Cuprina主要活跃在秋天。在不同的月份产卵可以避免这些物种之间的竞争。这也将它们结合在一起。如果产卵延迟得足够小，就会导致这两种飞蝇种群迅速灭绝，前提是它们不能适应。

{"title":"Reduced oviposition period promotes blowfly population extinction in Nicholson’s model","authors":"I. Elbaz","doi":"10.1080/08898480.2022.2051367","DOIUrl":"https://doi.org/10.1080/08898480.2022.2051367","url":null,"abstract":"ABSTRACT Blowflies use open wounds or the accumulation of feces or urine in wool to lay their eggs. The larvae that emerge cause lesions in the host sheep, which can lead to death. They are found in Australia, New Zealand, and the United Kingdom. Nicholson’s model describes the population dynamics of the Australian blowfly (Lucilia Cuprina). It incorporates environmental variation. The extinction of these flies depends on the time to oviposition and the time between generations. The Lyapunov function, which is positive with a negative derivative, provides the condition for the stability of the equilibrium point: the oviposition period must be sufficiently short, because the shorter it is, the more it favors the extinction of the species. The zero solution is the only equilibrium point, synonymous with the extinction of the population. Another species of blowfly, Lucilia Sericata, also attacks sheep in Australia. Both blowflies are ectoparasites of warm-blooded vertebrates, particularly domestic sheep. These two blowflies are related to share same mitochondrial DNA sequences, although the two species are distinct. Presumably to avoid competition between them. the egg-laying time of each species does not occur at the same time of year: L. Sericata prefers warmer months, thus in summer, while L. Cuprina is mainly active in autumn. Laying of eggs in different months allows avoiding competition between these species. This also binds them together. A sufficiently small egg-laying delay then leads to the rapid extinction of both blowfly populations, provided they do not adapt.","PeriodicalId":49859,"journal":{"name":"Mathematical Population Studies","volume":"29 1","pages":"158 - 171"},"PeriodicalIF":1.8,"publicationDate":"2022-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45320539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"社会学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Poisson regression-ratio estimators of the population mean under double sampling, with application to Covid-19 双重抽样下总体均值的泊松回归比估计，并应用于Covid-19

IF 1.8 3区社会学 Q3 DEMOGRAPHY

Mathematical Population Studies

Pub Date : 2022-05-03 DOI: 10.1080/08898480.2022.2051988

H. Koç, Caner Tanış, T. Zaman

ABSTRACT Poisson regression is used to deal with count data. The Poisson regression ratio estimator of the population mean is extended from single to double sampling. This is made possible by the provision of the population mean of an auxiliary variable. The mean square errors of the proposed estimators are expressed up to the first order. Theoretical and numerical results demonstrate that the proposed double-sampling Poisson-regression ratio estimator has a lower mean square error than the double-ratio and the single-sampling estimator. For Covid-19, the minimum mean square errors yielded by the proposed estimator of the total number of cases are 0.095 cases per day and 67.8 cases, compared with 0.112 cases per day and 84.8 cases with the double-ratio estimator.

用泊松回归处理计数数据。将总体均值的泊松回归比估计从单采样推广到双采样。这可以通过提供辅助变量的总体平均值来实现。所提出的估计量的均方误差表示到一阶。理论和数值结果表明，所提出的双采样泊松回归比估计比双采样和单采样估计具有更小的均方误差。对于新冠肺炎，该方法的最小均方误差分别为每天0.095例和67.8例，而双比方法的最小均方误差分别为每天0.112例和84.8例。

引用次数: 5

首页上一页

下一页尾页

类型

全部化学•材料生命科学医学物理工程技术环境•农林材料科学地球科学法学管理学化学环境科学与生态学计算机科学教育学经济学农林科学人文科学生物学数学物理与天体物理心理学综合性期刊其他工业工程理学历史学农学文学信息工程

数据库

全部 ACS Publications Elsevier ieeexplore Springer The Royal Society of Chemistry Wiley

期刊

Mathematical Population Studies

全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.

﹀