bluuebunny/crossref_metadata_2025 huggingface dataset:
Clostridium piliforme Infection in Two Farm-raised White-tailed Deer Fawns (Odocoileus virginianus) and Association with Copper Toxicosis
Authors: Brooks J. W. , Whary M. T. , Hattel A. L. , Shaw D. P. , Ge Z. , Fox J. G. , Poppenga R. H.
Published: September 2006

Necropsy of 2 white-tailed deer fawns who died acutely revealed diarrhea and melena in case No. 1 and no gross changes in case No. 2. Histologically, the livers of both deer displayed multifocal coagulative necrosis, with infiltrations of neutrophils, macrophages, and lymphocytes. By Warthin-Starry staining, bundles of filamentous bacteria were identified within hepatocytes at the periphery of the necrotic foci in case No. 1. There was multifocal myocardiocyte necrosis in case No. 1 and multifocal lymphoid necrosis of the Peyer's patches in case No. 2. Clostridium piliforme 16S ribosomal ribonucleic acid gene was detected in both livers by polymerase chain reaction (PCR) with C. piliforme-specific primers. The liver copper levels in both cases were normal to slightly elevated. The kidney copper level in case No. 2 was elevated. This represents the first published cases of Tyzzer's disease in deer, a novel use of PCR for the diagnosis of C piliforme infection, and a possible association between copper toxicosis and Tyzzer's disease.
Fatal Herpesvirus Encephalitis in a Reticulated Giraffe (Giraffa camelopardalis reticulata)
Authors: Hoenerhoff M. J. , Janovitz E. B. , Richman L. K. , Murphy D. A. , Butler T. C. , Kiupel M.
Published: September 2006

Fatal meningoencephalitis caused by equine herpesvirus-1 (EHV-1) was diagnosed in a reticulated giraffe ( Giraffa camelopardalis reticulate). The giraffe died following a history of stumbling, incoordination, and abdominal pain. Gross examination of the brain revealed asymmetric edema and red-brown discoloration, predominantly within the telencephalon. Microscopically, there was perivascular lymphohistiocytic cuffing, multifocal gliosis, and neuronal necrosis in the cerebrum. Necrotic neurons contained acidophilic intranuclear inclusions. EHV-1 was isolated from the brain of the giraffe, and polymerase chain reaction was positive on sections of the brain. Immunohistochemistry using an EHV-1-specific antibody identified positive staining in neurons, astrocytes, and endothelial cells. The giraffe had been housed with a group of zebras that were serologically positive for EHV-1 and suspected as the source of infection. This raises concerns for cross-species transmission of EHV-1 when housing equids together with other species in zoologic collections.
Immunohistochemical Detection of Yml/Ym2 Chitinase-like Lectins Associated with Hyalinosis and Polypoid Adenomas of the Transitional Epithelium in a Mouse with Acute Myeloid Leukemia
Authors: Marchesi F. , Minucci S. , Pelicci P. G. , Gobbi A. , Scanziani E.
Published: September 2006

An 8-month-old PML/RARα knock-in female mouse developed a promyelocytic-like myeloid leukemia with an expected latency. At necropsy, besides the typical findings associated with myeloid leukemia, a severe unilateral hydronephrosis was observed. By histopathologic examination, 2 polypoid adenomas arising from the transitional epithelium of the renal pelvis and ureter were detected. The epithelial cells of the polypoid adenomas showed accumulation of hyaline eosinophilic material within the cytoplasm. Large amounts of extracellular eosinophilic crystals were also associated with the transitional cell adenomas. Immunohistochemical analysis revealed that the eosinophilic intracytoplasmic material and the extracellular eosinophilic crystals were composed of Ym proteins. A unilateral hyaline droplet tubular nephropathy was associated with the myeloid leukemia. Expression of Ym proteins characterized both the neoplastic myeloid infiltrates and the tubular hyaline droplets. In the present PML/RARα knock-in female mouse, the accumulation of Ym proteins associated with the myeloid leukemia and with the polypoid adenomas of the transitional epithelium underlies 2 distinct pathogenetic mechanisms.
Primary Cerebral Hemangiosarcoma in a 6-Week-Old Dog
Authors: Gabor L. J. , Vanderstichel R. V.
Published: September 2006

A primary cerebral hemangiosarcoma was identified in a 6-week-old, female, cross-breed dog. Grossly, the tumor mass was poorly demarcated from the adjacent neuropil, hemorrhagic, and caused effacement of the right dorsolateral cerebral hemisphere. Microscopically, the tumor was composed of an infiltrative mass of small vascular channels lined by neoplastic endothelial cells that stained variably with factor VIII-related antigen and negatively with glial fibrillary acidic protein. This is the first description of a primary intracranial hemangiosarcoma in an immature dog.
Estimates of Pregnancies Averted Through California's Family Planning Waiver Program in 2002
Authors: Foster Diana Greene , Biggs M. Antonia , Amaral Gorette , Brindis Claire , Navarro Sandy , Bradsberry Mary , Stewart Felicia
Published: September 2006

CONTEXT: During its first year of operation (1997‐1998), California's family planning program, Family PACT, helped more than 750,000 clients to avert an estimated 108,000 pregnancies. Given subsequent increases in the numbers of clients served and contraceptive methods offered by the program, updated estimates of its impact on fertility are needed.

METHODS: Claims data on contraceptives dispensed were used to estimate the number of pregnancies experienced by women in the program in 2002. Medical record data on methods used prior to enrollment were used to predict client fertility in the absence of the program. Further analyses examined the sensitivity of these estimates to alternative assumptions about contraceptive failure rates, contraceptive continuation and contraceptive use in the absence of program services.

RESULTS: Almost 6.4 million woman‐months of contraception, provided primarily by oral contraceptives (57%), barrier methods (19%) and the injectable (18%), were dispensed through Family PACT during 2002. As a result, an estimated 205,000 pregnancies—which would have resulted in 79,000 abortions and 94,000 births, including 21,400 births to adolescents—were averted. Changing the base assumptions regarding contraceptive failure rates or method use had relatively small effects on the estimates, whereas assuming that clients would use no contraceptives in the absence of Family PACT nearly tripled the estimate of pregnancies averted.

CONCLUSIONS: Because all contraceptive methods substantially reduce the risk of pregnancy, Family PACT'S impact on preventing pregnancy lies primarily in providing contraceptives to women who would otherwise not use any method.
Understanding Sex Partner Selection From the Perspective of Inner‐City Black Adolescents
Authors: Andrinopoulos Katherine , Kerrigan Deanna , Ellen Jonathan M.
Published: September 2006

CONTEXT: Black adolescents in inner‐city settings are at increased risk for HIV and other STDs. Sex partner characteristics, as well as individual behavior, influence individuals' STD risk, yet little is known about the process of sex partner selection for adolescents in this setting.

METHODS: Semistructured in‐depth interviews were conducted during the summer and fall of 2002 with 50 inner‐city black adolescents (26 females and 24 males) who had been purposively recruited from an STD clinic. Content analysis was used to study interview texts.

RESULTS: Young women desire a monogamous romantic partner, rather than a casual sex partner; however, to fulfill their desire for emotional intimacy, they often accept a relationship with a nonmonogamous partner. Young men seek both physical and emotional benefits from being in a relationship; having a partner helps them to feel wanted, and they gain social status among their peers when they have multiple partners. For men, these benefits may help compensate for an inability to obtain jobs that would improve their financial and, as a result, social status. Both women and men assess partners’STD risk on the basis of appearance.

CONCLUSIONS: HIV and other STD prevention initiatives must go beyond the scope of traditional messages aimed at behavior change and address the need for social support and socioeconomic opportunities among at‐risk, inner‐city adolescents.
Promoting Female Condom Use to Heterosexual Couples: Findings from a Randomized Clinical Trial
Authors: Witte Susan S. , El‐Bassel Nabila , Gilbert Louisa , Wu Elwin , Chang Mingway , Hill Jennifer
Published: September 2006

CONTEXT: The female condom remains the only female‐initiated method for preventing pregnancy and STDs, including HIV. Innovative methods for promoting its use, and for involving male partners in its use, are needed.

METHODS: A sample of 217 women and their main male sexual partners were randomly assigned to one of three study conditions: a six‐session relationship‐based STD prevention intervention provided to the couple together, the same intervention provided to the woman only or a single‐session education control provided to the woman only. Assessments were conducted at baseline and three months postintervention. Contrast coding was used to examine whether the effects of the two active interventions differed from those of the control intervention, and whether the effects of the two active interventions differed from each other. Regression analyses were used to estimate treatment effects.

RESULTS: During follow‐up, participants in either active intervention were more likely to use a female condom with their study partner and with all partners, and used female condoms at a higher rate with all partners, than individuals assigned to the control intervention; at the end of three months, they were more likely to intend to use the condom in the next 90 days. No significant differences in outcomes were found between the active intervention groups.

CONCLUSIONS: Focusing on both a woman and her main male sexual partner is efficacious in increasing female condom use and intention to use among heterosexual couples at risk for HIV and other STDs.
Do U.S. Family Planning Clinics Encourage Parent‐Child Communication? Findings from an Exploratory Survey
Authors: Jones Rachel K.
Published: September 2006

CONTEXT: Clinics that receive Title X funding have a mandate to encourage parent‐child communication for minors seeking family planning services. Little is known about the programs and practices that clinics have adopted to achieve this goal, or whether clinics not receiving Title X funds encourage family participation.

METHODS: As part of a larger project examining parental engagement among adolescents using family planning clinics, 81 clinics that served 200 or more adolescent contraceptive clients in 2001 completed a questionnaire containing closed‐ and open‐ended items. Topic areas included clinic counseling and policies regarding clients younger than 18, activities to improve parent‐child communication and community relations. Frequency distributions were calculated for the prevalence of activities, and cross‐tabulations were used to compare prevalence by clinic characteristics.

RESULTS: Every clinic engaged in at least one activity to promote parent‐child communication, and nine in 10 offered multiple activities. Most of the clinics used counseling sessions to talk to adolescent clients about the importance of discussing sexual health issues with parents (73–94%, depending on the reason for the visit). More than eight in 10 clinics (84%) distributed pamphlets on how to talk about these issues. A substantial minority (43%) offered or referred interested individuals to educational programs designed to improve communication. Some of these exploratory findings reflect the prevalence of activities among all U.S. family planning clinics that serve adolescent clients.

CONCLUSIONS: Evaluation and expansion of clinic efforts to promote voluntary communication about sexual health issues between parents and children could help encourage family participation.
Characteristics of Vanadium Alloyed Carbonitrided Steel for Rolling Bearing Applications
Authors: Lee JS , Song BH , Yoo SJ , Park CN , Han HS
Published: September 2006

Today, most bearings for automotive transmission operate in an environment of severe debris contaminated lubrication. Thus, to develop the bearings that have a long life under the lubrication environment, micro-alloyed forging steel with a vanadium element based on medium-carbon steel and a carbonitriding heat-treatment process have been developed. Initially, the variation of grain size caused by an amount of aluminum and nitrogen was investigated. The hot deformation behavior was evaluated by means of a Gleeble tester. In general, it is extremely difficult to obtain sufficient nitrogen in the case-hardened layer by a conventional carbonitriding process. However, the application of the newly developed steel has not only the increment of nitrogen content in the case-hardened layer, but also the additional benefit that heat treatment costs could be cut effectively. In addition, we have investigated the retained austenite and precipitation behavior of V(CN), and the evaluated rolling contact fatigue life of a heat-treated specimen. As a result, we identified that the fatigue life of developed steel samples, under contaminated lubrication environment, is about five times better than comparative steel. The micro-structural degradation mechanism during fatigue testing was elucidated.
Evaluation of the Simulated Material Microstructures Using the Image Processing and Image Analyzing Methods
Authors: Hafez Haghighat SM , Karimi Taheri A.
Published: September 2006

With the development of computing systems for data processing, the image processing and image analyzing methods have been developed on the basis of pixel assessment. These methods can analyze and detect the images by assigning a value for each pixel and using the matrices calculations. In the present research, two methods have been used to assess the simulated material microstructures. In the first method, the vertices of the microstructure are counted to determine accurately the mean grain size by the Euler's relationship, while in the second method, the image processing and image analyzing methods are utilized to assess the microstructure image. To verify the accuracies of the methods their results were compared with the experimental results achieved using the standard Heyn intercept method. It was found that in comparison with the common grain size measurement, the image processing method presents a higher accuracy compared with the Eulers's relationship. More information about the microstructure properties such as the mean grain size and the size of the largest grain in the presence of second phase particles are evaluated.
Accounting
Authors: Blanchard Ralph
Published: September 2006

This article's purpose is to give an overview of accounting concepts and issues relevant to the actuary. To do this, it is divided into the following sections:

Purpose of accounting

Types of accounting

Principal financial statements

Sources of accounting rules

Selected accounting concepts

Common accounts for insurance companies.
Affine Models of the Term Structure of Interest Rates
Authors: Webber Nick
Published: September 2006

Several families of interest rate models are commonly used to model the term structure of interest rates. These include market models, used extensively in the money markets; affine term structure models, widely used in the bond markets; and Heath, Jarrow, and Morton (HJM) models, less widely used but applied to both the bond and money markets.
AFIR
Authors: Prime Catherine
Published: September 2006

This article has no abstract.

Catherine Prime sadly passed away in February 2004. The Editors‐in‐Chief and Publisher would like to acknowledge the fact that the author was not able to correct her proofs.
Aggregate Loss Modeling
Authors: Panjer Harry H.
Published: September 2006

This article provides a brief overview of aggregate loss modeling.
Ammeter,Hans (1912–1986)
Authors: Kupper Josef
Published: September 2006

The article describes the life and the important scientific research of the Swiss actuary Hans Ammeter.
Annual Statements
Authors: Babcock Nathan J.
Published: September 2006

Insurance companies and other business organizations that engage in the business of insuring or reinsuring property–casualty exposures are usually required to file
Annual Statements
with the governmental agencies that regulate insurance operations in the pertinent geographic region. These Annual Statements are detailed financial documents that provide information that are not typically available in a company's annual report (such as is provided to stockholders, for example). However, Annual Statements are generally available to interested members of the public, as they are documents in the public record.
Insolvency
Authors: Cummins J. David
Published: September 2006

The objective of insurance is to provide risk pooling and diversification for individuals and business firms facing the risk of loss of life or property due to contingent events. Each individual unit insured through an insurance enterprise pays a premium to the insurer in return for the promise that those individuals suffering a defined loss event during the coverage period will be compensated for the loss by the insurance company. Some period of time elapses between the date of issuance of the insurance contract and the payment of losses to claimants against the pool. This can be anywhere from a few weeks, as in the case of short‐term property insurance policies, to a period of years or decades, as in the case of long‐tail liability insurance policies, life insurance, and annuities. The insurance company holds the funds generated by collecting and investing premiums to finance the claim payments that are eventually made against the pool. Because losses can be larger than expected, insurance companies hold equity capital over and above the expected value of future claim costs in order to ensure policyholders that claims will be paid in the event of adverse deviations. Nevertheless, there is a significant risk that the funds held by the insurer will be inadequate to pay claims. This is the risk of insolvency or bankruptcy, which provides the primary rationale for the intense regulation of insurance companies worldwide.
Beard,RobertEric (1911–1983)
Authors: Teugels Jozef L.
Published: September 2006

Apart from being one of the authors of the first book on Risk Theory, Beard contributed to other aspects of actuarial science as well.
B
rownian Motion
Authors: Salminen Paavo
Published: September 2006

Brownian motion, also called Wiener process, is probably the most important stochastic process. Its key position is due to various reasons. The aim of this introduction is to present some of these reasons without striving to a complete presentation. The reader will find Brownian motion appearing also in many other articles in this book, and can in this way form his/her own understanding of the importance of the matter.

Our starting point is that Brownian motion has a deep physical meaning being a mathematical model for movement of a small particle suspended in water (or some other liquid). The movement is caused by ever moving water molecules that constantly hit the particle. This phenomenon was observed already in the eighteenth century but it was Robert Brown (1773–1858), a Scottish botanist, who studied the phenomenon systematically and understood its complex nature. Brown was not, however, able to explain the reason for Brownian motion. This was done by Albert Einstein (1879–1955) in one of his famous papers in 1905. Einstein was not aware of the works of Brown but predicted on theoretical grounds that Brownian motion should exist.
Capital in Life Assurance
Authors: Forfar David O.
Published: September 2006

The article looks at the requirements for capital in a life company. The requirements for capital, over and above that are required to cover a valuation of the company's financial liabilities, depend on the strength of the valuation basis and the risks run by the company.
Claim Number Processes
Authors: Garrido José
Published: September 2006

Risk theory models describe the uncertainty associated with the claims recorded by an insurance company for losses incurred by its policy holders. The claims frequency and the claims severity are two important components of these models. This article centers on models for the frequency of losses.

Even if an insurance company were able to maintain the exact same portfolio of policies over time, the number of claims recorded would still vary from year to year. Such natural fluctuations are modeled through the claim number random variable.

Over time, claim counts evolve according to a stochastic process: the claim number process. While other sections discuss specific claim number processes in greater detail, the general features are given here.
Claim Size Processes
Authors: Cheung Ka Chun , Yang Hailiang
Published: September 2006

This article is a survey of claim size processes. We present an overview of the renewal process model, and both the light‐tailed and the heavy‐tailed claim distributions are discussed. Recent developments in the insurance risk models in which the claim size processes are nonstationary or have dependence structure are also covered.
Reserving in Non‐Life Insurance
Authors: Hesselager Ole , Verrall Richard
Published: September 2006

This article summarizes the issues in reserving for non‐life insurance. The basic terms are defined, and some of the most frequently used approaches are introduced. Introductions are given to further articles in this Encyclopedia on specific methods for reserving, and some of the practical issues are discussed.
Collective Risk Theory
Authors: Tsai Cary Chi‐Liang
Published: September 2006

In this article, classical continuous‐time surplus process and its variations are introduced; several assumptions for the number of claims and for the times between claims are proposed. The time of ruin, the probability of ruin, and the surplus immediately before and at ruin caused by a claim are defined. Then an upper bound on and an asymptotic formula for the probability of ruin are given. Also, the mean discounted penalty is proposed, which is usually used to study a variety of interesting and important quantities, for example, moments and distribution functions. Finally, the maximal aggregate loss and the associated compound geometric distribution are discussed.
C
ramér–
L
undberg Condition and Estimate
Authors: Yang Hailiang
Published: September 2006

This article surveys the main results and developments of Cramér–Lundberg approximation. We present an overview of the classical results under the Lundberg–Cramér model, and the corresponding results in the cases of heavy‐tailed claim distribution are discussed. Recent developments in the diffusion perturbed insurance risk models and in the model in which an α‐stable Levy process is added to the compound Poisson process are covered.
Credit Risk
Authors: Gielens Geert
Published: September 2006

In this article, we present a brief overview of the most important aspects of credit risk and the way it is treated in financial markets. More specifically, we briefly cover subjects such as default probabilities, loss given default, credit default swaps, and collateralized debt obligations.
Underwriting Cycle
Authors: Klein Robert
Published: September 2006

The property‐casualty insurance industry is notorious for its pattern of rising and falling prices and supply of coverage, commonly known as the “underwriting cycle.” This article explains this phenomenon, reviews various theories about its causes, and discusses proposed government remedies. The “real cycle” in the price and supply of insurance is distinguished from the “accounting cycle” in reported performance ratios. Several hypothesized causes of the real cycle are examined, including adverse loss shocks, movements in interest rates, under‐pricing due to naivety or excessive risk taking, and greater uncertainty about the distribution of expected losses. Government policies that help to control claims costs will be the most effective in promoting greater market stability.
Decision Theory
Authors: Schmidt Klaus D.
Published: September 2006

Decision theory aims at unifying various areas of mathematical statistics, including the prediction of a nonobservable random variable, the
estimation
of a parameter of the probability distribution of a random variable, and the test of a hypothesis on such a parameter. Each of these problems can be formulated as a
statistical decision
problem.
Disability Insurance
Authors: Pitacco Ermanno
Published: September 2006

We first describe types of disability insurance products and common policy conditions. Then a probabilistic model for insurance covers providing disability annuities is defined, adopting a time‐discrete approach. The construction of actuarial values, premiums, and reserves follows. A more general actuarial framework is finally sketched, using the multistate approach.
Early Mortality Tables
Authors: Forfar David O.
Published: September 2006

The article begins by looking at what Ulpian's factors tell us about mortality in ancient Rome. The article then looks at the main mortality tables of the seventeenth, eighteenth, and nineteenth centuries.
Esscher Transform
Authors: Yang Hailiang
Published: September 2006

This article surveys the main results and developments of Esscher transform. We first present the original idea of Esscher and its applications to the problem of approximating the tail probabilities. The Esscher transform applied to the premium calculation, the Esscher premium principle, is then discussed. Recently, the Esscher transform has been applied to finance to tackle the problem of option pricing. Following Gerber–Shiu's framework, we provide an overview on this interesting development.
Genetics and Insurance
Authors: Macdonald Angus S.
Published: September 2006

Most actuarial modeling has concentrated on single‐gene disorders, because it necessarily relies on genetic epidemiology to parameterize any models, and that is where the epidemiology is most advanced. We can identify two broad approaches.

A top‐down approach treats whole classes of genetic disorder as if they were homogeneous. This avoids the need to model individual disorders in detail, which in the case of multifactorial disorders may be impossible just now anyway. If, under extremely adverse assumptions, either extra premiums or the costs of adverse selection are small, this is a useful general conclusion; see for examples. In the long run, this approach is limited.

A bottom‐up approach involves detailed modeling of individual disorders, and estimating the overall premium increases or costs of adverse selection by aggregation. Examples include models of breast cancer and ovarian cancer, Huntington's Disease, early‐onset Alzheimer's Disease, adult polycystic kidney disease and Alzheimer's Disease.
Generalized Linear Models
Authors: Kaas Rob
Published: September 2006

A wide class of claims reserving methods can be described as special cases of Generalized Linear Models. This class includes the Chain‐Ladder method, as well as the arithmetic and geometric separation method.
Hedging and Risk Management
Authors: Cairns Andrew J.G.
Published: September 2006

This article summarizes some of the techniques that are used to hedge derivative contracts and manage the risks that arise within a portfolio of derivatives. For simplicity of exposition, the article concentrates here on equity derivatives.

The most straightforward form of hedging is a buy‐and‐hold strategy. This involves finding the optimal mix of cash and equity that will, for example, minimize the variance of the hedging error at the maturity date of the derivative. However, this method can only reduce risk by a small amount. To improve on it, one needs to consider dynamic portfolio strategies, particularly ones where the optimal mix of cash and equity depends on the state of the market at given times in the future.
History of Actuarial Education
Authors: Forfar David O.
Published: September 2006

This article looks at the history of actuarial education where, from the start, there was a difference in approach between the Anglo‐Saxon world and Continental Europe. In the Anglo‐Saxon world, entry to the actuarial profession depended on passing the examinations set by the profession and it was not necessary to have gone to a university (although exemptions could be granted in certain countries from some of the earlier examinations if sufficient relevant academic training had been undertaken). In Continental Europe, entry to the profession depended, in the main, on having successfully completed the relevant courses at university (or technische hochschule) or having gained sufficient practical ‘on‐the‐job’ experience.
History of Actuarial Profession
Authors: Hickman James
Published: September 2006

A profession is an occupation or vocation requiring advanced study in a specialized field. The actuarial profession started out from life insurance and pension plans. Later, its development ran parallel to the accounting profession. To safeguard the goals and objectives of the profession, actuarial organizations were established on an international level but also on a national level where often rules for proper accreditation have been established. Economic and financial developments have broadened the required skills of an actuary. The future actuary will face new challenges that emerge from regulation, globalization and expanding knowledge.
Inflation: A Case Study
Authors: Di Lorenzo Emilia
Published: September 2006

The article deals with the impact of inflation on insurance business and, with regard to life insurance business, with the response of the insurance market. The introduction of innovative products, as indexed insurances, is framed in this order of ideas, and the main characteristics of these contracts are described.
I
nstitute of
A
ctuaries of
J
apan
Authors: Kuriyama Akira
Published: September 2006

The IAJ will have to respond in a proactive manner to the domestic deregulation and to the changing international circumstances, such as financial and economic internationalization and the spread of international accounting standards. The IAJ, thus, continuously needs to undertake further research activities to reinforce its function as an opinion maker, to uphold the integrity of the actuarial profession, and to promote internationalization. The IAJ is in the process of implementing plans to realize these goals.
Insurability
Authors: Gollier Christian
Published: September 2006

We first describe the competitive equilibrium of frictionless insurance markets with symmetric information. Risks are insurable in this economy in the sense that all mutually advantageous risk exchanges are realized at equilibrium. We then provide various reasons why many risks cannot be efficiently shared in our decentralized economy. Transaction costs, adverse selection, moral hazard, insurance fraud, and the inexistence of an objective distribution function do generate an insurability problem that requires public intervention. The heterogeneity of beliefs and the difficulties in diversifying individual risks are other reasons why some risks are not insurable, but this does not mean that insurance markets are inefficient.
Lapses
Authors: Fry Martin
Published: September 2006

A lapse is a failure by a policyholder to accept an insurer's offer to renew an expiring policy. Lapses differ from cancellations, which require specific action by a policyholder during the policy term. Insurers monitor lapse rates, as high lapse rates may indicate that an insurer's policies are uncompetitive. In practice, renewal rates are often monitored; they are calculated as (1‐lapse rates).
L
évy Processes
Authors: Pistorius Martijn R.
Published: September 2006

Lévy processes form a continuous time analogue of a random walk. Thanks to their generality, these processes have found a wealth of applications in insurance and even more in financial mathematics. Special attention is given to Wiener‐Hopf factorizations, subordinators, stable processes and to the connections with infinitely divisible processes.
Matching
Authors: Shiu Elias S. W.
Published: September 2006

This is a brief survey on various methods for matching assets with liabilities.
Mean Residual Lifetime
Authors: Cai Jun
Published: September 2006

This article reviews the properties of the mean residual lifetime of a distribution and considers the applications of mean residual lifetimes in insurance, finance, and reliability.
Mixture of Distributions
Authors: Panjer Harry H.
Published: September 2006

This article gives an overview of some probability distributions that are obtained as mixtures of known distributions.
Mutuals
Authors: Szuch William
Published: September 2006

This article outlines the concept of mutuality that comes from friendly societies, life companies, and general insurance. Reference is also made to mutuality in other facets of society and community structure.
Noncooperative Game Theory
Authors: Thijssen Jacco
Published: September 2006

Noncooperative game theory is, roughly, the mathematical theory of conflict. In this article its main ideas, concepts, and results are presented. Special focus is on the distinction between games of complete and incomplete information. Furthermore, attention is paid to some applications in actuarial sciences, namely adverse selection and moral hazard.
Non‐Life Insurance
Authors: Taylor Greg
Published: September 2006

The following items of terminology are equivalent: non‐life insurance, property–liability insurance, property and casualty insurance, and general insurance.

Non‐Life insurance is defined and distinguished from other forms of insurance. Classes of non‐life insurance are defined and discussed. Reinsurance is also defined.
Nonparametric Statistics
Authors: Brazauskas Vytaras
Published: September 2006

The intent of this article is to give a brief overview of nonparametric statistical methods. We first describe the most commonly used nonparametric procedures in standard statistical settings involving one, two, or more samples. Then we turn to more specialized topics, such asempirical estimation,resampling methods, andsmoothing techniques, which find frequent application in actuarial research and practice. In each case, the emphasis is on the description of the problem and a particular standard approach to its solution, rather than attempting to review all existing procedures that are available for the problem. Also, for each topic, a list of references that treat applications of these methods to actuarial problems is provided.
Nonproportional Reinsurance
Authors: Splitt Andrea
Published: September 2006

Whereas in proportional reinsurance the claims and the premium are divided between the primary insurer and the reinsurer in the ratio of their shares in the coverage granted for the individual risks, nonproportional reinsurance focuses on claims. The reinsurer pays a claim if the loss incurred by the primary insurer exceeds a certain agreed amount or level, known as the deductible. The cover granted for a portfolio may be broken into several segments known as layers. The various types of nonproportional treaties differ according to whether the cover applies to individual or to aggregate claims and, in the latter case, depending on the rules used to arrive at the aggregate: excess‐of‐loss cover, aggregate excess‐of‐loss cover, and largest‐claims cover. The premium for a nonproportional treaty is calculated on the basis of risk theory.

Nonproportional reinsurance is an effective way of improving the ratio between the primary insurer's loss burden and premium income, as it passes specifically the peak losses on to the reinsurer.
Parameter and Model Uncertainty
Authors: Cairns Andrew J.G.
Published: September 2006

Almost every actuarial problem involves one or more sources of risk. The task of an actuary is to assess the following risks:

To derive a distribution for the outcome at some fixed future time or at a series of future dates.

To make decisions or observations based on this risk assessment (e.g. to provide a risk measure, to set a premium rate, to calculate the reserve, to decide on an investment strategy).
Pooling in Insurance
Authors: Aase Knut K.
Published: September 2006

Risk sharing resulting in pooling of risk is considered. We take the perspective of Pareto optimal risk sharing, originating from a model introduced by Karl Borch in the late 1950s, and discuss when pooling may result, and also what is needed for pooling not to be optimal. Finally, we illustrate by some examples, including mutual insurance schemes, and also a limited liability partnership.
Quota‐Share Reinsurance
Authors: Dickson David C.M.
Published: September 2006

Quota share reinsurance is described in this article.
Ratemaking
Authors: McClenahan Charles L.
Published: September 2006

The goal of the ratemaking process is the establishment of actuarially sound rates for property and casualty insurance, or other risk transfer mechanisms. Because ratemaking generally requires that rates be established prior to the inception of the insurance, a rate is ‘an estimate of the expected value of future costs’. Such rates are actuarially sound if they provide for all of the expected costs of the risk transfer and appropriately reflect identified individual risk characteristics.

Many state rating laws in the United States require that insurance rates be ‘not inadequate, excessive or unfairly discriminatory’. If a rate is actuarially sound, it is deemed to meet these regulatory requirements without regard to the extent to which the actuarial expectations are consistent with the actual developed experience.

This article will introduce and discuss the basic elements of property and casualty actuarial ratemaking. The examples and illustrations have been substantially simplified, and it should be noted that the methods presented herein are but a few of the methods available and may not be appropriate for specific actuarial applications.
Reinsurance This is based in part on an article written by the same author and published in
Foundations of Casualty Actuarial Science, Fourth Edition
by the Casualty Actuarial Society (2001).
Authors: Patrik Gary
Published: September 2006

Reinsurance is a form of insurance. A reinsurance contract is legally an insurance contract; the reinsurer agrees to indemnify the ceding insurance company for a specified share of specified types of insurance claims paid by the ceding company for a single insurance policy or for a specified set of policies. The nature and purpose of reinsurance is to reduce the variability of the financial costs to insurance companies arising from the occurrence of specified insurance claims. It thus enhances innovation, competition, and efficiency in the insurance marketplace. This article briefly discusses the types of reinsurance companies, and the functions, forms, and costs of reinsurance. It also outlines a ‘typical’ reinsurance program for a medium‐sized insurance company. All these topics are more fully covered in other referenced articles and books.
Reinsurance Pricing
Authors: Schmitter Hans
Published: September 2006

The technical premium is the sum of the risk premium, the fluctuation loading, and the loading for management expenses. In practice, excess‐loss risk premiums are estimated using experience‐rating or exposure rating. Stop‐loss risk premiums are usually estimated by means of rather simple mathematical models. More accurate methods for stop‐loss calculations are applied for determining sliding‐scale premium rates.
Reliability Analysis
Authors: Natvig Bent
Published: September 2006

In reliability analysis, one is interested in studying the reliability of a technological system being small or large. As examples of small systems, we have washing machines and cars, whereas tankers, oil rigs, and nuclear power plants are examples of large systems. By the reliability of a system, we will mean the probability that it functions as intended. It might be tacitly assumed that we consider the system only for a specified period of time (for instance, one year) and under specified conditions (for instance, disregarding war actions and sabotage). Furthermore, one has to make clear what is meant by functioning. For oil rigs and nuclear power plants, it might be to avoid serious accidents such as a blowout or a core‐melt.

Reliability analysis is a very helpful tool in risk assessment when determining the insurance premiums for risks, especially of rare events, associated with large systems consisting of both technological and human components. Furthermore, reliability analysis is relevant in risk management of any technological system, the aim now being to say something helpful on how to avoid accidents. This is an area of growing importance representing an enormous challenge for an insurance company.
Risk‐Based Capital Allocation
Authors: Albrecht Peter
Published: September 2006

This contribution is intended to serve as a survey of techniques of risk‐based capital allocation. Before going into technical detail, however, some words have to be spent on the conceptions of risk‐based capital and capital allocation.
Risk Classification, Practical Aspects This is based in part on an article written by the same author and published in
Foundations of Casualty Actuarial Science, Fourth Edition
by the Casualty Actuarial Society (2001).
Authors: Finger Robert J.
Published: September 2006

Risk classification involves the formulation of different premiums for the same coverage based on group characteristics. That is, the task is to price an individual insured, but the available claim data for that individual is insufficient for the purpose. The recourse is to measure group costs and assume that the individual belongs to a certain group. The grouping process may proceed in several dimensions (e.g. class, territory, use).

Premiums should vary because underlying costs vary. Costs may vary because of different claim frequency or average claim size, different administrative expense requirements, different investment income potential, or differing assessments of risk. Risk classification proceeds by identifying variables that distinguish these costs among different insureds. In addition to classification variables, premiums can also vary because of the choice of different exposure bases, individual risk rating methods, and marketing or underwriting strategies.

Various criteria, actuarial, operational, social, and legal, have been suggested for formulating classification variables. Actuarial criteria attempt most accurately to group individual insureds into groups that (1) are relatively homogeneous, (2) are sufficiently large to estimate relative cost differences (credibility), and (3) maintain stable mean costs over time (reliability).

Operational criteria include objective definitions, reasonable administrative expense, and verifiability. Social criteria include privacy, causality, controllability, and affordability.
Risk Minimization
Authors: Møller Thomas
Published: September 2006

Risk minimizationis a theory from mathematical finance that can be used for determining trading strategies. The theory of risk minimization was instituted by Föllmer and Sondermann who essentially suggested the determination of trading strategies for a given liability by minimizing the variance of future costs defined as the difference between the liability (or claim) and gains made from trading on the financial market.
Scale Distribution
Authors: Klugman Stuart A.
Published: September 2006

When modeling losses, it is often necessary to increase the losses through multiplication by a constant (usually reflecting inflation). It is convenient when selecting a parametric model, to choose one that when the random variable is multiplied by a constant, the new distribution is of the same type. Such distributions are called scale distributions.
Seasonality
Authors: Stramer Osnat
Published: September 2006

This article considers development in estimating and removing seasonal components from an observable discrete‐time series.
Life Reinsurance
Authors: Orbanz Ulrich
Published: September 2006

The article highlights some differences of life reinsurance compared to general reinsurance, covering demand, types of reinsurance, actuarial aspects, retention, pricing, and financing. Additional remarks are made regarding group business and living benefits.
Stochastic Optimization
Authors: Glynn Peter W.
Published: September 2006

Uncertainty is present in virtually all decision‐making environments. In some applications settings, one may safely choose to ignore the presence of uncertainty because its influence on the optimal decision is likely to be small. In other settings, one would ideally like to explicitly incorporate the presence of uncertainty into a mathematical formulation of the problem, because it is a priori clear that an optimal solution will be significantly influenced by the presence of uncertainty. Loosely speaking, stochastic optimization is the set of mathematical and computational tools that have been developed in order to characterize or compute optimal solutions to mathematical models involving such stochastic elements.

From a mathematical viewpoint, stochastic optimization has two main subdisciplines. The first is that of stochastic control. Stochastic control is concerned with optimization problems in which the optimizing solution is ‘infinite dimensional’ (or of very high dimensionality) in character. The second subdiscipline involves finite‐dimensional stochastic optimization. Much of the corresponding literature focuses on intelligent ‘search’ methods for numerically computing the optimal setting of a (finite‐dimensional) vector of decision variables.
Vibrational Optical Activity of Pharmaceuticals and Biomolecules
Authors: Dukor Rina K. , Nafie Laurence A.
Published: September 2006

This article describes recent progress in the field of vibrational optical activity (VOA) as a probe of the structural properties of pharmaceutical and biological molecules. A strong emphasis is placed on vibrational circular dichroism (VCD) owing to its more advanced state of development. Raman optical activity (ROA) is included in the first two sections for completeness; other reviews give additional information about ROA.
1–3,8
The article focuses on the practical aspects of VCD spectral measurement and interpretation. This is supplemented by examples that serve to illustrate the principal areas of VOA application. VCD is defined as the difference in the absorbance of the left circularly polarized (LCP) versus right circularly polarized (RCP) infrared (IR) radiation for a chiral molecule undergoing a vibrational transition. A pair of enantiomers will produce VCD spectra that are equal and opposite in sign and a racemic mixture will have a null VCD signal. VCD can be measured for all kinds of chiral molecules, irrespective of their size. In practice, measurements are often carried out in solution but, with the new advances in instrumentation, it is now possible to measure spectra of solids and mulls. Compared to other optical techniques such as electronic circular dichroism (CD) and IR absorption, VCD is unique because it combines the optical activity property of CD with the rich structural fingerprint region of IR. The discovery and first measurements of VCD occurred in the early 1970s. Although over a dozen practitioners have published close to a 1000 papers since then, it is only recently that VCD instrumentation has become available commercially for nonspecialists. Applications span a variety of fields from chemical and pharmaceutical to biological. The VCD technique can be used for the determination of absolute configuration of small chiral molecules or larger natural products. It can also be used to follow a chiral synthesis both for stereochemistry and for optical purity, and to study the secondary structure of large proteins and small peptides, and the conformation of nucleic acids and sugars. Some recent reports have also shown the unique sensitivity of ROA in the study of viruses and in protein‐folding experiments. VOA is now fulfilling its promise of becoming a technique that is broadly used for stereochemical and conformational studies of all varieties of chiral molecules, both natural and synthetic.