bluuebunny/crossref_metadata_2025 huggingface dataset:
The organic carbon pool of permafrost regions on the Qinghai–Xizang (Tibetan) Plateau
Authors: Mu C. , Zhang T. , Peng X. , Cao B. , Zhang X. , Wu Q. , Cheng G.
Published: September 2014

Abstract. Presently, Northern Circumpolar Soil Carbon Database was not involved permafrost organic carbon storage on the Qinghai–Xizang (Tibetan) Plateau (QXP). Here we reported a new estimation of soil organic carbon (SOC) pools of the permafrost regions on the QXP at different layers from the top 1 to 25 m depth using a total of 706 soil profiles. The SOC pools were estimated to be 15.29 Pg for the 0–1 m, 4.84 Pg for the 1–2 m, 3.89 Pg for the 2–3 m and 43.19 Pg for the layer of 3–25 m. The percentage (64.3%) of SOC storage in deep layer (3–25 m) on the QXP was larger than that (38.8%) in the northern circumpolar permafrost region. In total, permafrost region on the QXP contains approximately 67.2 Pg SOC, of which approximately 47.08 Pg (70.1%) stores in perennially frozen soils and deposits. The present study suggested that the permafrost organic carbon pools of Northern Hemisphere should be updated from 1672 to 1739 Pg.
Da "grécia antiga" ao estado integral: propostas políticas e o respaldo "histórico" construído por Miguel Reale
Authors: Cazetta Felipe
Published: September 2014

Projetos autoritários de Estado centralizado e forte foram abundantes no Brasil durante os anos 1930. Entretanto, o fato de defenderem a suspensão do regime democrático não tornava este grupo homogêneo. Deste modo, o artigo apresentado tem como objetivo evidenciar a formação do Estado Integral esboçado por Miguel Reale, Secretário Nacional de Doutrina, para a Ação Integralista Brasileira. Seu projeto, revestido pelo corporativismo, buscou fixar suas raízes na tradição e na religiosidade, no intuito de combater o comunismo e o liberalismo.
Em nome da ordem: a cultura política anticomunista nas forças armadas brasileiras (1935-1985)
Authors: Teixeira Mauro Eustáquio Costa
Published: September 2014

Este artigo analisa as formulações de caráter anticomunista presentes nas “ordens do dia” através das quais os comandantes militares brasileiros comemoravam, a cada ano, as vitórias das Forças Armadas em 1935, contra a chamada “Intentona Comunista”, em 1964, no golpe que derrubou o governo constitucional de João Goulart. Buscamos, nestes discursos, elementos que permitem caracterizar o anticomunismo militar como uma cultura política que orientou o comportamento das instituições castrenses do Brasil ao longo do século XX.
Reviewer Acknowledgements for Journal of Food Research, Vol. 3, No. 5
Authors: Dong Bella
Published: September 2014

Reviewer Acknowledgements for Journal of Food Research, Vol. 3, No. 5
Automatic Identification of Ficus deltoidea Jack (Moraceae) Varieties Based on Leaf
Authors: Nasir A Fakhri A , A Rahman M Nordin , Mat Nashriyah , Mamat Rasid
Published: September 2014

Currently, the traditional method used to identify Ficus deltoidea Jack (Moraceae) varieties require the plant taxonomists to observe and examine the leaf morphology of herbarium or live specimens. An automated variety identification system would ease the herbs collector to carry out valuable plant identification work. In this paper, a model for F. deltoidea varieties identification based on their leaf shape, color and texture was developed. Five different varieties of F. deltoidea were used in the proposed work with sixty nine sample data collected for each of varieties. First, the F. deltoidea leaves were plucked and the picture of leaves is then taken by a digital scanner in the format of JPEG.  For leaf shape, a total of fourteen shape features were extracted based on basic geometric features. The mean of different color channels was calculated in leaf color feature extraction. Furthermore, four texture features based on gray-level co-occurrence matrix was implemented to extract leaf texture properties. By using the leaf structure, a set of three different leaf properties which are leaf shape, color and texture features was extracted. The features weight is then calculated using eigenvalues coefficient in principal component analysis. The best principal components are retained for identification experiments. Lastly, Nearest Neighbor with Euclidean distance was used in variety identification based on three different leaf properties mentioned above. The effectiveness of different leaf features are demonstrated in the identification experiment.
Logic of Interval Uncertainty
Authors: Kuzmin Evgeny A.
Published: September 2014

The scientific category of uncertainty refers to that group of terms, an interpretation of which is not unambiguous and exact. In non-eliminability of the category soft content barrier there is an objective transition to the interval uncertainty. This research is an attempt to solve the issue of estimating the interval uncertainty based on methods of a logical analysis and a comparison. The approach presented by the paper is opposed to known methods of a mechanical selection of values following a given function. In the course of the research, there has been introduced a concept of the “tenversion uncertainty” for scientific use. Overall results obtained from the research allow calculating values of the interval uncertainty and assess their quality. The scientific competency of methods is achieved in theoretically tested solutions.
Economic Growth and Internet Usage Impact on Publication Productivity among ASEAN’s and World’s Best Universities
Authors: Gholizadeh Hossein , Salehi Hadi , Embi Mohamed Amin , Danaee Mahmoud , Ordi Ali , Tanha Farid Habibi , Ebrahim Nader Ale , Osman Noor Azuan Abu
Published: September 2014

Measuring the number of papers which are published each year, publication productivity is the factor which shows the reputation of universities and countries. However, the effect of growing economy and using internet on the publication productivity in Asian countries has not been discovered yet. The present research is going to figure out the publication productivity among the elite universities in Asian countries and also ten top universities around the world in the last twenty years (from 1993 to 2012). Furthermore, the current research is aimed to study the relationship among publication, gross domestic product (GDP) and internet usage. It is worth to mention that the publication of the top Ten Malaysian Universities was regarded for the similar period of time. To get the exact numbers of documents like papers, conference articles, review papers and letters which are published by the universities in the last twenty years, the writer of the same paper used the Science Direct database. Moreover, the data for GDP and the number of internet usage was collected through the World Bank database (World Data Bank).To compare all kinds of publications,one-way ANOVAwas used and to investigate the impact of economic growth and internet usageon publication productivity, multiple regression analysis was applied.The results showed that therate of publication growth was 1.9, 20.9, and 65.5 % in top universities in the world, ASEAN countries and Malaysia, respectively.The results also showed thatthere was a positive and significant correlationbetween GDP and the number of internet users with the number of publications in ASEAN and Malaysian universities. Internet usagehad much more influence in comparison withthe GDP in predicting the number of publicationsamong these groups except for top ten Malaysian universities from 2003 to 2012. In summary, publication trends in top ten Malaysian and ASEAN universities are promising. However, policy makers and science managersshouldspend much more percentage of their GDP on Internet facilities and research studies that their outputs lead to more rapid economic growthand internet usage.
Announcement of Retraction
Authors: Oudah Ali , I. Mohd Izzeldin , Hameed A.
Published: September 2014

The editorial board announced that this article has been retracted on September 30, 2014. If you have any further question, please contact us at: mas@ccsenet.org
Ratio Estimators Using Coefficient of Variation and Coefficient of Correlation
Authors: Sangngam Prayad
Published: September 2014

This paper introduces ratio estimators of the population mean using the coefficient of variation of  study variable and auxiliary variables together with the coefficient of correlation between the study and auxiliary variables under simple random sampling and stratified random sampling. These ratio estimators are almost unbiased. The mean square errors of the estimators and their estimators are given. Sample size estimation in both sampling designs are presented. An optimal sample size allocation in stratified random sampling is also suggested. Based on theoretical study, it can be shown that these ratio estimators have smaller MSE than the unbiased estimators. Moreover, the empirical study indicates that these ratio estimators have smallest MSE compared to the existing ones.
Impact of Landuse Change on River Floodplain Using Public Domain Hydraulic Model
Authors: Akbari Abolghasem , Mozafari Golamali , Fanodi Mohsen , Hemmesy Maliheh Sadat
Published: September 2014

Floodplains are land areas adjacent to rivers and streams that are subjected to recurring inundation. Owing to their continually changing nature, floodplains and other flood-prone areas need to be examined in the light of how they might affect or be affected by landuse change. In this research, the effect of land use changes on floodplain is investigated. Major landuse change has occurred in Azaran watershed during the investigation period. Irrigated farmland has decreased by about 52%. However, bare lands, dry farm lands, and rangeland have increased by 12.40%, 17.25% and14.46%, respectively. The extent of floodplain was determined based on the annual maximum instantaneous flood for different return periods using Hydrologic Engineering Centers River Analysis System (HEC-RAS) coupled with HEC-GeoRAS which is a tool for processing geospatial data in ArcGIS. Water surface profile data and velocity data exported from HEC-RAS simulations were processed by HEC-GeoRAS for floodplain mapping. It was found that the floodplain has increased due to land use change from 1956 to 2007. This study showed that floodplain areas in irrigated farmlands have increased by 151.99% and 68.63% for return period of 25 and 50 years, respectively.
Differential TAM receptor–ligand–phospholipid interactions delimit differential TAM bioactivities
Authors: Lew Erin D , Oh Jennifer , Burrola Patrick G , Lax Irit , Zagórska Anna , Través Paqui G , Schlessinger Joseph , Lemke Greg
Published: September 2014

The TAM receptor tyrosine kinases Tyro3, Axl, and Mer regulate key features of cellular physiology, yet the differential activities of the TAM ligands Gas6 and Protein S are poorly understood. We have used biochemical and genetic analyses to delineate the rules for TAM receptor–ligand engagement and find that the TAMs segregate into two groups based on ligand specificity, regulation by phosphatidylserine, and function. Tyro3 and Mer are activated by both ligands but only Gas6 activates Axl. Optimal TAM signaling requires coincident TAM ligand engagement of both its receptor and the phospholipid phosphatidylserine (PtdSer): Gas6 lacking its PtdSer-binding ‘Gla domain’ is significantly weakened as a Tyro3/Mer agonist and is inert as an Axl agonist, even though it binds to Axl with wild-type affinity. In two settings of TAM-dependent homeostatic phagocytosis, Mer plays a predominant role while Axl is dispensable, and activation of Mer by Protein S is sufficient to drive phagocytosis.
Understanding nitrile-degrading enzymes: classification, biocatalytic nature and current applications
Authors: Rodríguez Jorge Ricaño
Published: September 2014

Nitrile-degrading enzymes commonly known as nitrilase enzymes are able to metabolize nitrile-substituent compounds and they have several industrial applications, for example: in drugs synthesis. It is also common to observe their exploitation for obtaining chemical compounds with commercial interests related to cosmetics production, paints and additives. In addition, these are frequently used in the active metabolites synthesis of pesticides. Due to the catalytic nature of such proteins, it is possible to take advantage of their biotechnological potential to be applied in various scientific fields including synthetic biocatalysis and environmental remediation, since they have been successfully used for soils nitrile-wastes decontamination such as cyanide, bromoxynil and benzonitrile. On the other hand, these enzymes are considered very important intermediaries of metabolic pathways related to indolic compounds that are produced by bacteria, plants and superior fungi, acting in most cases as vegetal growth hormones. Given the fact that indole-derivative molecules play an important role in physiological responses in superior organisms, nitrilase enzymes may be considered as important part of unknown multi-enzymatic secondary metabolites pathways. In light of the above considerations, this review attempts to summarize the current status of nitrilase research and describing in detail the main characteristics of nitrile-converting enzymes with emphasis on fungal proteins, including their function and catalytic selectivity. Likewise, their relationship with plant metabolism and biotechnological importance in bioremediation processes is discussed.
Plaguicidas en México: usos, riesgos y marco regulatorio
Authors: Ortíz Irmene , Avila-Chávez Marco A. , Torres Luis G.
Published: September 2014

El presente documento describe la situación actual referente a la reglamentación de la producción, distribución, almacenamiento y uso de los plaguicidas en México. Se muestran datos de morbilidad como consecuencia del uso de estos productos como un referente de sus efectos sobre la salud humana, así como, los sitios en la República Mexicana en donde la incidencia es mayor. Adicionalmente, se presenta una revisión de la regulación nacional e internacional sobre plaguicidas, así como, las distintas dependencias gubernamentales, organizaciones civiles y centros de investigación involucrados en el tema en México. La información presentada sugiere que a pesar de las regulaciones y restricciones de uso de los plaguicidas, éstos pueden representar un grave problema de salud para los trabajadores y poblaciones expuestas, así como, de contaminación de suelos y aguas en México.
The brightness ratio of H Lyman‐α/H2 bands in FUV auroral emissions: A diagnosis for the energy of precipitating electrons and associated magnetospheric acceleration processes applied to Saturn
Authors: Tao Chihiro , Lamy Laurent , Prangé Renée
Published: September 2014

We propose that the ratio of the auroral brightness of H Lyman‐α to that of far ultraviolet H2 and the absolute value of the H2 brightness provide good indicators of the acceleration versus nonacceleration processes for field‐aligned auroral electron precipitation in the Saturn magnetosphere‐ionosphere coupled system. This finding is based on model results indicating that this ratio is a decreasing function of the auroral electron energy over the whole auroral energy range, as previously suggested by Cassini observations. For electron energies above 5 keV, the results agree with the Knight relation, as in the environments of the Earth and Jupiter. On the other hand, decreasing electron flux with increasing electron energies below a few keV is also found and alternately explained as a nonacceleration reflecting the magnetospheric plasma distribution and/or wave‐particle interactions.
Posttranslational Oxidative Modifications of Proteins
Authors: Schöneich Christian
Published: September 2014

This manuscript represents an update to our previous article in this encyclopedia, focusing on posttranslational oxidative protein modifications. This update focuses specifically on the development of enrichment strategies for oxidatively modified peptides and/or proteins for proteomic applications and on the improvement of mass spectrometric characterization of peptides containing oxidative modifications.
Glaciology – Ultratrace Analysis of Samples from Remote Areas
Authors: Barbante Carlo , Cozzi Giulio
Published: September 2014

Remote regions such as Antarctica and Greenland have been studied for many years because of the treasure of important chemical information preserved in their pristine ice caps. Considering their geographical position, the influence of anthropogenic pollution of many chemical compounds can be detected by sophisticated analytical approaches to detect their ultralow concentrations (down to femtograms per gram). To be reliable, these chemical data must be obtained after observing severe pre‐analytical cleanliness protocols to preserve the original elemental concentration from contamination due to sampling and general handling operations. Furthermore, very sensitive analytical techniques such as inductively coupled plasma mass spectrometry (ICP‐MS) have to be used to detect ultralow levels of contaminants in snow and ice samples. Here, we present a description of all the steps necessary to carry out analytical measurements at ultratrace levels in snow and ice samples collected in remote regions such as the Polar ice caps.
HandheldX‐ray Fluorescence Spectrometry
Authors: Tohyama Shigeo , Piorek Stanislaw
Published: September 2014

Handheld X‐ray fluorescence (HHXRF) spectrometry is a relatively new phenomenon in the landscape of analytical techniques. It morphed out of the traditional energy‐dispersive X‐ray fluorescence (EDXRF) spectrometry, a mature analytical technique that successfully established itself in laboratory and some industrial environments either in the form of a large, stationary, or more recently as a portable, battery‐operated system.EDXRFhas been ready for a long time for expansion and migration out of laboratory into the field. This seasoned, well‐researched analytical method offers unique features that when combined together make it especially attractive and useful for field applications. It is truly nondestructive to the object tested; it can analyze simultaneously many elements in solid, powder, or liquid samples; and it provides results in real time and it is relatively inexpensive. However, it was only technological developments of the last decade that made finally possible the expansion ofEDXRFinto field and industrial environments. Recent availability of miniature, low‐power X‐ray tubes, thermoelectrically cooled high‐resolution semiconductor detectors, and ever smaller yet more powerful electronics and microprocessors made the design of a handheld X‐ray fluorescence (XRF) analyzer a reality. Once available, these small handheld and weighing less than 1.5 kg analyzers gained widespread acceptance as a tool of choice in many areas of industry. Perhaps the best indicator of their success and usefulness is the fact that over the last decade about 48 000HHXRFanalyzers were placed in the market, the number which is most likely several times bigger than the overall number of all laboratoryEDXRFsystems installed worldwide. The focus of this article is the present state of development of handheldXRFspectrometers. An overview of their features and performance is given, and typical applications served by these instruments are discussed. Finally, an attempt is made to outline the possible directions of future development of this versatile method.
Musicology, Statistics in
Authors: Beran Jan
Published: September 2014

Quantitative musicology is a relatively new field of statistical applications that is increasingly important due to the availability of digitized data. In principle, all fields of statistical theory are potentially useful. In contrast to genuinely quantitative sciences, many questions in musicology have no unique ‘correct’ answer, and often no strictly objective optimality criterion exists to find an optimal solution to a problem. In this paper, some typical examples illustrate the role of statistics in musicology
Change Point Methods in Genetics
Authors: Chen Jie
Published: September 2014

In this review article, recent applications of change point methods in genetics will be discussed. The latest advances in bio‐technology have provided new tools for scientists to carry out health and life science research. The array, or microarray, technology has made it possible to simultaneously quantify expression patterns of thousands or hundreds of thousands of genes in various cell lines, tissues, and conditions. The resulting datasets from various experiments using microarray technology are of high‐throughput and cast challenges to data analysts.

Specifically, to study the genetic reasons of tumor growth, cancer formation, and genetic diseases, geneticists can now use microarray technology to conduct DNA copy number experiments to obtain gene positions, log base 2 ratio intensities, and DNA copy numbers along the genome. It turns out that identifying loci of DNA copy number variations along the chromosome or genome can be viewed as a change point problem of detecting the changes presented in the sequence of log ratio intensities. The author will discuss the background of DNA copy number experiments, especially the experiments using the array comparative genomic hybridization (aCGH) technique, the resulting aCGH data, and the appropriate change point methods that can be used to analyze the aCGH data. Several applications of the change point methods to the analysis of fibroblast cell line data, the breast tumor data, and the breast cancer data will be given.
Panel Count Data
Authors: Sun Jianguo
Published: September 2014

Panel count data usually refer to data arising from studies on recurrent events in which study subjects are followed or observed only periodically rather than continuously. In these situations, the objective of interest is about the occurrence of some events that can occur multiple times or repeatedly and the studies resulting in this type of information are often referred to as event history studies. There are many fields that produce panel count data and they include medical studies, reliability experiments and social science. This article will review some basic concepts about panel count data, some common issues and questions of interest in their analysis as well as the corresponding statistical procedures that are available. In particular, we will discuss estimation of the mean function of the underlying counting process characterizing the occurrence of the events, comparison of several processes and regression analysis of panel count data. Some discussion will also be provided for situations that involve dependent or informative observation processes.
Statistical Software
Authors: Wegman Edward J. , Solka Jeffrey L.
Published: September 2014

This article is a short exposition on the state of the art with regard to statistical software, along with some prognostications as to the future trends in the area. The article is somewhat biased in its discussions, with a focus on those packages that seem most promising in their current and future role in the academic research communities.
Multivariate Symmetry and Asymmetry
Authors: Serfling Robert J.
Published: September 2014

Univariate symmetry has interesting and diverse forms of generalization to the multivariate case. Here several leading concepts of multivariate symmetry—spherical, elliptical, central, and angular—are examined and various closely related notions discussed. Methods for testing the hypothesis of symmetry and approaches for measuring the direction and magnitude of skewness are reviewed.
Generalized Order Statistics
Authors: Kamps Udo
Published: September 2014

Order statistics and record values appear in many statistical applications and are widely used in statistical modeling and inference. Both models describe random variables arranged in ascending order of magnitude. Generalized order statistics provide a unified approach to a variety of models of ordered random variables with different interpretations, such as ordinary order statistics, sequential order statistics, progressively type II censored order statistics, record values,kth record values, and Pfeifer's records. These models can be effectively applied, for example, in reliability theory. Here, an order statistic represents the life length of somek‐out‐of‐nsystem, which is an important technical structure. For this application, sequential order statistics serve to describe influences of failures on the life‐length distributions of the remaining components. Record values are used in shock models, and they are closely connected with the occurrence times of some corresponding nonhomogeneous Poisson process, with some minimal repair scheme, and with the relevation transform. The distribution theory of generalized order statistics is established along the lines of ordinary order statistics. By this, we find that many well‐known properties of order statistics and record values are also valid for generalized order statistics. The results on generalized order statistics concern their distribution theory, relations and bounds for moments, characterizations of distributions, preservation of aging properties and stochastic ordering, extreme‐value theory, and statistical inference with respect to model and distribution parameters.
Continuous Multivariate Distributions
Authors: Balakrishnan N.
Published: September 2014

In this article, we present a concise review of developments on various continuous multivariate distributions. We first present some basic definitions and notations. Then, we present several important continuous multivariate distributions and list their significant properties and characteristics.
Occupancy Distributions
Authors: Charalambides Ch. A.
Published: September 2014

Occupancy distributions are defined on the stochastic model of random allocation of balls of different kinds intondistinguishable urns. The reduction of the joint distribution of the occupancy numbers, when a specific number ofmballs are allocated, to the joint conditional distribution of independent random variables given their sum, when the number of balls allocated is unspecified, is a powerful technique in the study of occupancy distributions. Using this technique, the distribution of the numberKiof urns occupied byiballs each is derived in terms of the distribution of the independent random variables. In particular, the distribution of the numberK = n − K0of occupied urns is deduced and the distribution of the numberWkof balls required until the occupancy of a predetermined numberkof urns is obtained. Several applications and a generalization of the occupancy model are presented.
Digamma and Trigamma Distributions
Authors: Sibuya Masaaki
Published: September 2014

Digamma distributions are mixture distributions of logarithmic series distributions, and hence heavy‐tailed distributions, which have two parameters. The distributions vary widely with the parameter values; if one parameter is larger, the distribution is close to the logarithmic series distributions. If this parameter is near zero, the distribution is reduced to trigamma distributions, which are close to zeta distributions or Zipf's law.
Chi‐Squared Tests ‐ Recent Advances
Authors: Nikulin Mikhail , Voinov Vassilly
Published: September 2014

Chi‐squared goodness‐of‐fit tests for parametric families of distributions are discussed. Different methods of unknown parameters estimating are compared and some modifications of the Pearson statistic depending on methods of estimation are discussed.
False Discovery Rate
Authors: Abramovich Felix , Benjamini Yoav
Published: September 2014

For the multiple hypotheses testing problem consider the proportion of falsely rejected hypotheses (false discoveries) among the total number of rejections. The expected value of this proportion, called the False Discovery Rate (FDR), is a useful criterion to control as an alternative to the traditional familywise error rate (FWE) that suffers from low power properties when the number of tested hypotheses is large. In a way, controlling FDR is adaptively inbetween ignoring multiplicity altogether and a conservative control of FWE. Several FDR controlling procedures are presented and others are reviewed. Various extensions and applications of the FDR are discussed.
Multivariate Uniformity, Liang‐Fang‐Hickernell‐Li Test of
Authors: Kotz Samuel , Nadarajah Saraless
Published: September 2014

A test of multivariate uniformity attributable to Liang, Fang, Hickernell, and Li is discussed.
Kurtosis
Authors: Zenga Michele
Published: September 2014

The interpretation of the kurtosis index β2proposed by Karl Pearson is first examined. The Moors' indexTbased on quantiles and some partial orderings of kurtosis (by Van Zwet, Laurence, and Loh) are presented. Zenga's new approach to kurtosis, working for symmetrical as well as for asymmetrical distribution, is introduced. This latter approach is based on the definition of a particular transformation increasing kurtosis; a kurtosis curve, for the left and the right side of a distribution, can thus be obtained.
Generalized Variance
Authors: Gupta Ashis Sen
Published: September 2014

Generalized variance (GV), proposed by Wilks, is an one‐dimensional measure of multidimensional scatter. It plays an important role in both theoretical and applied research. GV has been extended to Standardized GV (SGV) to enable comparison of scatters in differing dimensions. Interesting results on the distribution, estimation, and testing of GVs and SGVs have been emerging. Also, these measures have been finding novel applications in a variety of applied problems, ranging from such age‐old areas as agriculture and sample surveys to the modern developments in signal processing and Bioinformatics.
Generalized Canonical Variables
Authors: Sengupta Ashis
Published: September 2014

Often the random vector variable, X, being encountered, for example, in atmospheric, biological, economic and environmental and other research, is of a large dimension but admits of meaningful grouping(s) into two or more mutually exclusive and exhaustive subvectors. Dimension reduction techniques are then sought to obtain “representative” new variables for each group to be formed by taking suitable compounds of the components within that group. This results in the substantially reduced dimensional vector variable Y to represent X. This greatly facilitates the associated computational and inferential statistical analyses. Hotelling's construction of canonical variables for the case of two groups of quantitative variables has been generalized in various directions to yield Generalized Canonical Variables that encompass more than two groups, both quantitative and qualitative components in X, order constraints imposed by the user on the compounding coefficients, and so on. The availability of packages makes the implementation of such techniques for real‐life problems quite feasible and attractive. On the inferential side, a variety of new types of hypotheses is posed: determination of optimal number of groups, best grouping for the same number of groups, and so on. While the corresponding distribution theory is quite involved, some interesting results are, nevertheless, emerging also. This topic is a fertile area and is in need of further theoretical and applied research, which should be very useful to a wide variety of practitioners.
Predicting Preclinical Disease by Using The Mixed‐Effects Regression Model
Authors: Sheng Shan L. , Brant Larry J.
Published: September 2014

Most methods of disease prediction are generally restricted to logistic or Cox proportional hazards model regression using only baseline values of the risk factor, and where the individuals age and sex account for most of the predictive capacity of the method. This chapter presents a method of risk prediction appropriate for repeated measures or time‐dependent risk factors from longitudinal studies. The method is based on posterior probabilities calculated from mixed‐effects regression models to model intra‐ and inter‐individual differences in the serial risk factor measurements, to predict a disease‐related outcome or other future event according to age changes within gender groups. While aging is inevitable and the occurrence of disease increases with age, disease and aging are not synonymous. Disease is a selective event that occurs in only some members of the population; others maintain a greater degree of physiological function as they age and remain relatively disease free. Thus, longitudinal data that considers each individual as their own control and the use of an appropriate method of prediction can play an important role in promoting a healthy human life throughout the aging process.
Nonparametric (Distribution‐Free) Quality Control Charts
Authors: Chakraborti Subha
Published: September 2014

Control charts that are typically based on the assumption of a specific form of a parametric distribution, such as the normal, are called parametric control charts. In many applications, however, there is not enough information to justify this assumption and control charts that do not depend on a particular distributional assumption are desirable. Nonparametric or distribution‐free control charts can serve this broader purpose. A key advantage of nonparametric charts is that its in‐control run length distribution is the same for all continuous process distributions. This means, for example, that the false alarm rate and the in‐control average run length of a nonparametric chart is the same for all continuous distributions. This is not true for parametric control charts in general and consequently their in‐control robustness can be a legitimate concern. Nonparametric charts are often more robust and efficient than their normal theory counterparts under heavy‐tailed and/or asymmetric distributions. In this paper we discuss developments, mostly in the area of univariate nonparametric control charts; this includes cases when the underlying parameters are specified as well as when they are unknown and are therefore estimated from the data. The majority of the charts are for monitoring the location; few charts are available for scale.
Chance—II
Authors: Mellor D. H.
Published: September 2014

This article is a critical survey of theories of chance, that is, of the objective empirical probabilities postulated by scientific theories of microphysics, evolution, genetics, and epidemiology. It distinguishes the chances from inductive and subjective probabilities; traces the development of theories of chance, from Laplace's eighteenth century classical theory to later frequency, limiting‐frequency and propensity theories; and sketches the epistemology of chance and explanations of why subjective probabilities should match known chances.
Continuum Regression
Authors: Sundberg Rolf
Published: September 2014

When, in a multiple regression, regressors are near‐collinear, so‐called regularized or shrinkage regression methods can be highly preferable to ordinary least squares, by trading bias for variance. Continuum regression, introduced by Stone and Brooks in 1990, ties together several more classical regularized regression methods, such as principal components regression, partial least squares regression, and ridge regression.
Agricultural Surveys
Authors: Vogel (Retired) Frederic A.
Published: September 2014

In this entry, an overview of the history of the development of various statistical procedures used to forecast and measure agricultural production is provided. Though the examples mostly apply to the United States (with the agricultural statistics as developed by the United States Department of Agriculture), some methods used in other countries are also mentioned at appropriate places.
Self‐Selected Samples
Authors: Rutherford Andrew
Published: September 2014

The term “Self‐Selected Samples” is explained. The nature of selection with respect to such samples is described, its relation to other sampling techniques is considered briefly and a distinction between strong and weak selection is made. Strong self‐selected samples are not representative of the population of interest and may very likely differ on pertinent factors. Hence, there are serious problems in generalizing inferences from self‐selected samples to their populations. A very brief outline is provided for three statistical approaches to problems with self‐selected samples: the use of covariates, mixture modeling, and selection modeling.
Human Capital
Authors: Dagum Camilo
Published: September 2014

This entry deals with the concept of human capital and its monetary value estimation. The basic assumptions and limitations of the traditional prospective (actuarial) and retrospective (cost of production) methods are discussed. A more efficient estimation procedure, the latent variable‐actuarial method, is presented and illustrated using information from the 1983 US Federal Reserve Board sample survey of income and wealth distribution. The main results obtained are the standardized value of each household HC latent variable, the average HC by age of the household heads, the average national HC, the monetary value of each household HC, and its size distribution.
Risk Measures and Economic Capital for (Re)Insurers
Authors: Tsanakas Andreas
Published: September 2014

This contribution relates to the use of risk measures for determining (re)insurers' economic capital requirements. Alternative sets of properties of risk measures are discussed. Furthermore, methods for constructing risk measuresviaindifference arguments, representation results, and reweighting of probability distributions are presented. How these different approaches relate to popular risk measures, such as value‐at‐risk, expected shortfall, distortion risk measures, and the exponential premium principle, is also dealt with. The problem of allocating aggregate economic capital to subportfolios (e.g., insurers' lines of business) is then considered, with particular emphasis on marginal‐cost‐type methods. The relationship between insurance pricing and capital allocation is briefly discussed, based on concepts such as the opunity and frictional costs of capital and the impact of the potential of default on insurance rates.
Decision Trees
Authors: Smith Jim Q. , Thwaites Peter
Published: September 2014

A decision tree finds many uses in the representation and analysis of finite discrete models of risk. In this article, we review the different uses of this theory and compare it with some other frameworks of decision inference. We then illustrate how the decision tree can be used as a framework for an extensive form analysis, in the context of risks associated with decisions leading to the prosecution of a criminal court case.
Multiattribute Modeling
Authors: Stewart Theodor J.
Published: September 2014

We discuss the role of multiattribute modeling, or problem structuring, in the context of multicriteria decision making. Within this context, criteria for evaluating or comparing alternative decision options are represented in terms of operationally defined attributes describing the alternatives, on the basis of which specific objectives or goals may be defined. Attention is given to the process of eliciting the criteria relevant to a particular decision context by interaction with decision makers and/or other stakeholders, after which we turn to the practicalities of constructing an operationally meaningful set of attributes. A number of guidelines are presented for purposes of selecting a final set of attributes to be used in decision analysis, often structured into a hierarchical value tree. Finally, we discuss the manner in which conflicting views of different stakeholder groups need to be taken into consideration.
Players in a Decision
Authors: French Simon
Published: September 2014

Different people with different roles may be involved in a decision—decision makers, experts, stakeholders, and decision analysts. Each has different interests and responsibilities in the decision‐making process and they interact in different ways. Understanding and respecting these differences is an important aspect in designing an appropriate decision or risk analysis.
Societal Decision Making
Authors: French Simon
Published: September 2014

The context of decision making in the public sector is somewhat different from that in business and industry. Decision making may not be confined to a small management team or board of directors; but rather involves many politicians, officials, and different political institutions. There is a need to address many stakeholder concerns and be seen to do so, particularly when the decision involves major technological, health, environmental, or other risks. The issues addressed tend to be more complex and involve many factors and uncertainties. Here, we discuss how decision and risk analyses fit into such contexts and the differences between their approach and that of cost–benefit analysis.
History of Epidemiologic Studies
Authors: Samet Jonathan M. , Apelberg Benjamin J.
Published: September 2014

Epidemiology can be defined as the scientific method used to assess health and its determinants in populations. Central to the method are measures of disease occurrence, and study designs for identifying causes of disease and quantifying their strength as causal agents. Because epidemiological studies directly address threats to human health, their findings, when available, have received emphasis in qualitative and quantitative risk assessments. Epidemiological data have the notable strength of being based on the “right” species, “real‐world” exposures, and often the full range of susceptibility. Observational data often have inherent limitations, but strategies are available to handle them. The development of radiation risk models from epidemiological studies and the use of the models in quantitative risk assessment have set a risk assessment paradigm grounded in epidemiological research.
Extreme Values in Reliability
Authors: Ferreira Ana
Published: September 2014

Extreme value (EV) theory provides probabilistic and statistical tools to deal with the largest or the smallest values of a sample, hence with tails of distribution functions. Applications of EV theory in reliability analysis can be found in many fields. For instance, in corrosion analysis, where pits of larger depth are of primary interest, as pitting corrosion can lead to the failure of metal structures, or, in strength of material problems where the principle of a chain being as strong as its weakest link dominates.

In the following text, main concepts of EV theory such as the maximum domain of attraction condition and EV distributions, peaks over threshold and the generalized Pareto distributions are discussed. Estimation within these frameworks, along with applications, are exemplified.
Hazard and Hazard Ratio
Authors: Ray Rose M.
Published: September 2014

The hazard function is a tool for describing the process of time to failure. Hazard functions arise in the context of survival analysis, also known as
failure analysis
, and provide a convenient way to visualize how the risk of failure changes with age or time. The exponential, Weibull, and lognormal distribution are three of the commonly used statistical models of time to failure. Hazard functions are used in epidemiology, medicine, ecology, engineering, and manufacturing settings, as well as in economics and finance. In this article, the mathematical concept of hazard and typical survival or failure time models are discussed.

The hazard ratio is a general way of examining relative risk. Cox proportional hazard models are examined, and nonparametric statistical methods for describing the relative risk of failure for two or more populations are discussed.
Fault Detection and Diagnosis
Authors: Gertler Janos J.
Published: September 2014

The article describes the detection and isolation (diagnosis) of faults (major equipment and sensor/actuator malfunctions) in engineering systems. The simpler, and less powerful methods do not rely on any mathematical model of the system; these include limit checking, special and multiple sensors, frequency analysis, and fault‐tree analysis. More advanced methods use mathematical models obtained from first principles or from experimental data. Such methods include on‐line parameter estimation, consistency checking, and principal component analysis. Two examples, one related to a simple electrical circuit and the other to a car‐engine subsystem, demonstrate the use of some of the methods.
Experience Feedback
Authors: Kjellén Urban
Published: September 2014

Experience feedback is the process by which information on the results of an activity is fed back to decision makers as new input to modify and improve subsequent activities. The main source of experience used in risk assessments is historic industrial systems. The experience emanates from incidents, failures, and normal operation, as well as from earlier risk assessments. Laboratory and field experiments provide complementary experience. Experience‐based knowledge from these activities is directed to the risk assessment team through different channels. The article distinguishes between channels for transfer of explicit and tacit knowledge. Experience databases and experience carriers play an important role in the first case, where experience carriers represent a higher degree of synthesis. If properly designed, the risk assessment team will constitute an arena for tacit knowledge exchange between risk analysts, personnel with operational experience, and systems designers. The article describes the processes for update of experience databases and experience carriers with new information. The need for documenting the experience basis in the risk assessment report is highlighted. An example from environmental risk assessments illustrates how experience feedback is achieved in practice.
Reliability Growth Testing
Authors: Pulcini Gianpaolo
Published: September 2014

Reliability growth is the process by which the reliability problems of a product are identified and corrected by introducing modifications in the product design and/or manufacturing process. Accordingly, the reliability of the product grows as the product goes through successive stages of the development program. Although reliability growth generally refers to improvements in a product's reliability, a very important field where reliability growth programs can find large application is the control of industrial accidents.

We discuss a number of stochastic models that are able to describe the reliability growth, either when improvement actions are introduced at failure occurrence (test‐analyze‐and‐fix program), or when the corrective actions are delayed and implemented in block at the end of each stage. Such models are classified intocontinuousanddiscontinuousmodels according to the assumed behavior of the product reliability with test time. Special attention is devoted to the nonhomogeneous Poisson process with power‐law intensity function, namely, the power‐law process, which is the stochastic representation of the well known deterministic growth model of Duane.
Multistate Systems
Authors: Levitin Gregory
Published: September 2014

This article presents a general model of multistate system that can function at different levels of performances. The measures of risk associated with undesirable system behavior are defined on the basis of an acceptability function that represents the required relation between the system performance and a demand. A reliability block diagram method based on a universal generating function technique is presented as an efficient tool for evaluating the risk measures for complex multistate series–parallel systems. The risk associated with combination of internal failures and external attack is considered and a defense strategy methodology is discussed.