First-order logic (FOL) is undecidable — that is, no algorithm exists that can decide whether a formula of FOL is valid or not. However, there are various fragments of FOL that are known to be decidable. FO, the two-variable fragment of FOL, is one of such languages [1,2]. FO is a first-order language where formulas have maximally two variables, no function symbols, but possibly do have equalit...

Several models have been proposed for scheduling the preventive maintenance (PM) of complex repairable systems in industry. These are often application-speci"c and some make unrealistic assumptions about stationarity of the process and quality of repairs. We investigate two principal types of general model, which have wider applicability. The "rst considers "xed PM intervals and is based on the...

The future of hospital Nuclear Medicine is triggered by the hospital organisation itself. In general, the hospital organisation of the present requires substantial changes in order to be competitive, economical, and abreast of the rapid progresses in medical developments and patient management. It also must be flexible to changes in health politics. In this special report an organisational hosp...

Cognitive abilities rise steeply from infancy to young adulthood and then are either maintained or decline to old age, depending on the specific ability. This pattern suggests corresponding continuities of mechanism and process, but it is striking that the fields of cognitive development and cognitive aging make little contact with each other's methods and theories. In this review we examine re...

We studied the developmental trends of temperament and character in a longitudinal population-based sample of Finnish men and women aged 20-45 years using the Temperament and Character Inventory model of personality. Personality was assessed in 1997, 2001, and 2007 (n = 2,104, 2,095, and 2,056, respectively). Mean-level changes demonstrated qualitatively distinct developmental patterns for char...

We describe gene-environment processes that may help account for individual differences in successful aging. Our emphasis is on successful aging in the cognitive domain, wherein individuals come to use a variety of strategies to cope with changes in cognitive capacities. We focus on the role of executive control in particular and define gene-environment correlation and nonshared environmental m...

Personality has been implicated in romantic and sexual relationships, but its association with childbearing is poorly understood. The authors assessed whether 3 personality traits--sociability, emotionality, and activity--predicted the probability of having children and whether having children predicted personality change. The participants were women and men from the Cardiovascular Risk in Youn...

Parenting a child with chronic disease provides a unique set of challenges for both mothers and fathers throughout all phases of the illness. However, fathers of these children are under-represented in existing research. This review focuses on the fathers of children with chronic disease included in 44 original articles. We address the challenges to the father's role as breadwinner, leader and ...