The effect of natural disaster on fertility,birth spacing,and child sex ratio: evidence from a major earthquake in India

Natural disasters can lead to significant changes in health, economic, and demographic outcomes. However, the demographic effects of earthquakes have been studied only to a limited degree. This paper examines the effect of the 2001 Gujarat earthquake on reproductive outcomes. This earthquake killed more than 20,000 people; injured 167,000; and caused massive losses to property and civic assets. Using data from two large-scale District-Level Household Surveys (2002–2004 and 2007–2008), we employ difference-in-difference and fixed-effect regression models to compare the outcomes across earthquake-affected districts and their neighboring districts during 5 years before and after the earthquake. We find that the earthquake led to significant rises in childbirth rates. It also reduced birth spacing among uneducated, tribal, and Muslim women, and the incidence of male births among rural women. We find considerable variation in the demographic effects of the earthquake across location, household socioeconomic status, and parental age and education.     

The Exact Null Distribution of Bartlett's Criterion

In this paper the exact null distribution of Bartlett's criterion for testing the homogeneity of variances in normal samples with unequal sizes is derived. The most general form of the density function is obtained by using contour integration. The expression for the cumulative distribution, being a series in simple algebraic functions, seems quite tractable for computation of the exact critical values. In the special case of equal sample sizes, some indication of the relation of the work of others to our series expansions has also been given.     

跨文化情景下组织试错学习机理研究

试错学习是企业全球化经营时应对文化冲突不可缺少的革新过程,已有研究对企业试错学习过程和机理尚缺乏深入探讨和明确阐释,尤其是针对跨文化情景下的研究较少。以美国医药行业著名跨国企业H公司作为研究对象,运用扎根理论方法,借助定性分析软件NVivo 8.0对访谈和二手所得资料进行分析,探究跨文化情景下组织试错学习的影响因素及机理模型。借助开放性编码、主轴编码和选择性编码分析得出试错学习的7个主要影响因素,包括跨文化学习能力、跨文化制度设计、稳定的跨文化经营、团队领导者素质、跨文化试错学习氛围、母公司的支持和跨文化适应性;选用著名跨国制药企业M公司案例进行理论饱和度检验,得到另一个影响因素即企业研发能力;据此构建试错学习过程模型。 研究结果表明,试错学习是一个循环往复的过程,可分为失败分析、试验开展和措施生效3个阶段;通过进一步分析各阶段的主要影响因素,构建跨文化情景下组织试错学习的机理模型。研究结论旨在为跨文化经营的企业有针对性地提升试错学习效率提供理论支持。     

Super efficient frequency estimation

In this paper we propose a modified Newton-Raphson method to obtain super efficient estimators of the frequencies of a sinusoidal signal in presence of stationary noise. It is observed that if we start from an initial estimator with convergence rate O_p(n⁻¹) and use Newton-Raphson algorithm with proper step factor modification, then it produces super efficient frequency estimator in the sense that its asymptotic variance is lower than the asymptotic variance of the corresponding least squares estimator. The proposed frequency estimator is consistent and it has the same rate of convergence, namely O_p(n^−3/2), as the least squares estimator. Monte Carlo simulations are performed to observe the performance of the proposed estimator for different sample sizes and for different models. The results are quite satisfactory. One real data set has been analyzed for illustrative purpose.     

An efficient and fast algorithm for estimating the parameters of two-dimensional sinusoidal signals

In this paper we propose a computationally efficient algorithm to estimate the parameters of a 2-D sinusoidal model in the presence of stationary noise. The estimators obtained by the proposed algorithm are consistent and asymptotically equivalent to the least squares estimators. Monte Carlo simulations are performed for different sample sizes and it is observed that the performances of the proposed method are quite satisfactory and they are equivalent to the least squares estimators. The main advantage of the proposed method is that the estimators can be obtained using only finite number of iterations. In fact it is shown that starting from the average of periodogram estimators, the proposed algorithm converges in three steps only. One synthesized texture data and one original texture data have been analyzed using the proposed algorithm for illustrative purpose.     

Judicious order acceptance and order release in make-to-order manufacturing systems

This paper explores a two-stage input control system for fixed capacity make-to-order manufacturing systems (with heavy job tardiness penalties), that selectively accepts incoming orders and holds the accepted ones in a pre-shop queue prior to releasing them to the shop floor. Single-stage input control systems that only allow orders to be delayed in a pre-shop queue (i.e. they do not allow some orders to be rejected) have been previously investigated and found to negatively impact overall due-date performance. The hypothesis motivating this research is that judiciously rejecting a subset of incoming orders can prevent the order release queue from being overloaded when a surge of demand occurs. The input control system is evaluated via experiments using a discrete-event simulation model of a fixed capacity manufacturing system. The experiments reported here suggest that holding orders in the pre-shop queue does not improve due date performance, and that judiciously rejecting orders on its own is a viable alternative mechanism of input control that can deliver improved performance.     

Identifying race and ethnicity in the 1979 National Longitudinal Survey of Youth

The 1979 National Longitudinal Survey of Youth is among the few surveys to provide multiple reports on respondents’ race and ethnicity. Respondents were initially classified as Hispanic, black, or “other” on the basis of data collected during 1978 screener interviews. Respondents subsequently self-reported their “origin or descent” in 1979, and their race and Hispanic origin in 2002; the latter questions conform to the federal standards adopted in 1997 and used in the 2000 census. We use these data to (a) assess the size and nature of the multiracial population, (b) measure the degree of consistency among these alternative race-related variables, and (c) devise a number of alternative race/ethnicity taxonomies and determine which does the best job of explaining variation in log-wages. A key finding is that the explanatory power of race and ethnicity variables improves considerably when we cross-classify respondents by race and Hispanic origin. Little information is lost when multiracial respondents are assigned to one of their reported race categories because they make up only 1.3% of the sample.

Amplitude modulated model for analyzing non-stationary speech signals

Recently amplitude modulated (AM) model in presence of additive white noise was used to analyze certain non-stationary speech data. It is observed that the assumption of white noise may not be proper in many cases. In this article, we consider the AM signal model in presence of stationary noise. We consider the least squares estimators and the estimators obtained by maximizing the Periodogram function. The two estimators are asymptotically equivalent. We study the theoretical properties of both estimators and observe their performances through numerical simulations. One speech data is analyzed and it is observed that the performance of the proposed estimators is quite satisfactory.     

Perceived threats of female infidelity, male proprietariness, and violence in college dating couples

According to evolutionary theory, men faced the adaptive problem of keeping their partners sexually faithful. In the current study, men's perception that their partners are interested in other men was hypothesized to be associated with more controlling behaviors in romantic relationships. Of the two dimensions of mating tactics, controlling and attentive behaviors, physically aggressive men were expected to be especially controlling, but not attentive. Using structural equation modeling with 116 college dating couples, women who reported greater interest in other men were perceived by their partners to do so and these men also exhibited more controlling behaviors, which were associated with physical aggression. Men's perception of women's interest in others was a more important predictor of male violence than women's actual interest in other men. The link between women's control tactics and their use of physical violence differed from men.