Characterization of discrete populations through conditional expectations of order statistics

In this paper we give some properties of the expected values of any order statistic when one of its adjacent order statistics is known (order mean function) from a sequence of sizen of independent and identically distributed random variables with discrete distribution. Furthermore, we obtain the explicit expressions of the distribution from these order mean functions, and finally, we show the necessary and sufficient conditions for any real function to be an order mean function. We also add some examples of characterization of discrete distributions from the order mean functions. Partially supported by Consejería de Cultura y Educación (C.A.R.M.), under Grant PIB 95/90.     

Properties of the elasticity of a continuous random variable. A special look at its behavior and speed of change

Belzunce et al. (1995 Belzunce, F., Candel, J., Ruiz, J.M. (1995). Ordering of truncated distributions through concentration curves. Sankhya 57:375–383. [Google Scholar]) define the elasticity for non negative random variables as the reversed proportional failure rate (RPFR). Veres-Ferrer and Pavía (2012 Veres-Ferrer, E.J., Pavía, J.M. (2012). La elasticidad: una nueva herramienta para caracterizar distribuciones de probabilidad. Rect@ 13:145–158. [Google Scholar], 2014b Veres-Ferrer, E.J., Pavía, J.M. (2014b). On the relationship between the reversed hazard rate and elasticity. Stat. Pap. 55:275–284.[Crossref], [Web of Science ®] , [Google Scholar]) interpret it in economic terms, extending its definition to variables that can also take negative values, and briefly present the role of elasticity in characterizing probability distributions. This paper highlights a set of properties demonstrated by elasticity, which shows many similar properties to the reverse hazard function. This paper pays particular attention to studying the increase/decrease and the speed of change of the elasticity function. These are important properties because of the characterizing role of elasticity, which makes it possible to introduce our hypotheses and knowledge about the random process in a more meaningful and intuitive way. As a general rule, it is observed the need for distinguishing between positive and negative areas of the support.     

爱尔杰小说中的人物塑造与“美国梦”主题阐释

霍瑞修·爱尔杰毕生创作了百余部“从乞儿到王子”式青少年励志作品，塑造了一大批对美国社会和传统文化影响颇深的人物形象。他们有的是性格单一、纯粹的扁平静态人物，有的是性格复杂、多变的圆形动态人物；还有的两类性格兼而有之。爱尔杰通过塑造一系列圆润丰满的人物形象，凸显和传递了“从乞儿到王子”式“美国梦”主题，使其蕴含的正能量成为影响和激励世代美国青少年乐观向上、不懈努力的精神食粮。     

二苯基乙炔及双二茂铁基乙炔与Fe_3(CO)_(12)的反应性研究

本文以十二羰基三铁Fe3(CO)12作为催化剂前体,研究了Fe3(CO)12分别与两种炔烃的反应性能。结果表明,当炔烃为二苯基乙炔时,可以同时得到四苯基环戊二烯酮化合物(1)和具有铁碳五元环状结构的双核铁羰基配合物(2);而与双二茂铁基乙炔反应时,仅获得了一个产物四二茂铁取代环戊二烯酮羰基铁配合物(3)。这类反应产物种类繁多,通过设计该类反应,可为合成不同取代基的环戊二烯酮类化合物提供一条新的途径。     

Counting casualties: A framework for respectful,useful records

Counting casualties in conflict zones faces both practical and ethical concerns. Drawing on procedures from risk analysis, we propose a general approach. It represents each death by standard features, having either essential value, for capturing the social and cultural meaning of individual casualties, or instrumental value, for relating patterns of casualties to possible causes and effects. We illustrate the approach with the choices involved in attempts to record casualties in Iraq and the Israel-Palestine conflict, and with natural disasters, as exemplified by Hurricane Katrina. We advocate institutionalizing the approach, so that recording casualties increases understanding, rather than suspicion.

氟化钕的制备条件及组成研究

探讨了以碳酸氢铵转型制备氟化钕工艺中的有关影响因素。用Ｘ射线衍射分析、Ｘ射线荧光光谱分析、电镜及热分析等方法对产物进行了表征。研究结果表明在选定的条件下，氟化钕沉淀速度快，容易过滤洗涤，稀土收率高，产品纯净     

A Note on the Characterization of Positive Linnik Laws

Recently, Jayakumar & Pillai (1996) gave an interesting characterization of the positive Linnik laws in terms of the spectrum function of an infinitely divisible law. This paper improves their result and simplifies their proof. It proves another characterization result in terms of the Pareto law. Further, it represents the positive Linnik random variable as a function of independent gamma random variables.     

A method for approximate fully bayesian analysis of parameters

Stochastic modeling of the geology in petroleum reservoirs has become an important tool in order to investigate flow properties in the reservoir. The stochastic models used contain parameters which must be estimated based on observations and geological knowledge. The amount of data available is however quite limited due to high drilling costs etc., and the lack of data prevents the use of many of the standard data driven approaches to the parameter estimation problem. Modern simulation based methods using Markov chain Monte Carlo simulation, can however be used to do fully Bayesian analysis with respect to parameters in the reservoir model, with the drawback of relatively high computational costs. In this paper, we propose a simple, relatively fast approximate method for fully Bayesian analysis of the parameters. We illustrate the method on both simulated and real data using a two-dimensional marked point model for reservoir characterization.     

Waiting time paradox and size biased sampling

Feller's (1971) 'Waiting time for the bus paradox1 is explained by the fact that the long Interarrival times have a better chance of covering an arbitrary point in time than do short interarrival times, This gives rise to size biased sampling and the length of the Interarrival time that contains the arbitrary point has a moment distribution, This paper deals with the characterization of the exponential distribution based on this 'Waiting time paradox'. Similar characterizations of the binomial, the negative binomial, the Poisson and the geometric distributions are obtained.     

Characterization of probability distributions through higher order gap

Weibull, Burr, Pareto and power function distributions have been characterized through the conditional moments of order statistics with higher gap and some of its important deductions are discussed.