Simulating space-time random fields with nonseparable Gneiting-type covariance functions

Statistics and Computing - Two algorithms are proposed to simulate space-time Gaussian random fields with a covariance function belonging to an extended Gneiting class, the definition of which...     

Evaluating risk: global fees and episodic care

In 1999, two articles in The Physician Executive -- "Part I: Global Theory and the Nature of Risk (July-August)." and "Part II: Towards a Choice-Based Model of Managed Care (October-November)" -- outlined the flaws of orthodox managed care theory and highlighted the unique advantages of moving to a genuinely market-based model, which included the concept of direct contracting for integrated episodes of care. This follow-up focuses on comparing an episode contracting system to a traditional capitated program and outlines the features that make this approach much more attractive to physicians, payers, and most importantly patients.     

The politic,philosophy and practice of OR—A personal view of the issues

It is almost 50 years since Sir Henry Tizzard created the group of scientists in RAF Fighter Command who were to coin the term ‘Operational Research’. The group still exists, though its work, and the work of other defence OR groups, has changed from solving acute operational problems by the extrapolation of observed data, to an attempt at predicting the outcome of policy choices that are beyond experience. Inevitably this has forced OR further into a political arena. Yet most OR practitioners are scientists used to investigating apolitical and benign nature. In this paper the author gives a personal view of what he believes OR is trying to achieve, what practical problems and pressures have to be faced and attempts to give guidance on how to proceed.     

Uncontrolled growth of human populations,geological background,and future prospects

The geological history of the Earth is replete with examples of animals proliferating to numbers that exceeded the ability of their environments to provide support. Enormous numbers and widespread distributions of many animals sometimes have been followed by drastic reductions in numbers of individuals and even by complete extinction of species. Humans of many nations are following the same trend of population growth beyond the ability of resources to insure adequate food, clothing, shelter, safety, and transport and beyond the ability of Earth to accommodate the wastes. Human population is now 5.4 billion, with a present doubling time estimated at about 35 years. Is this uncontrolled proliferation also to be followed by severe reduction or even extinction? If not, how may human population be stabilized or reduced to a level commensurate with resources and waste disposal—more effective contraceptives, increased abortion, high taxes on procreation? An approach more effective than religion or political control may be through better education (increased percentage literacy) that is known to correlate with lower birth rates and increased national income per capita in the about 167 nations of the world. If leadership cannot soon rise to face this situation, human inhabitation of the Earth may become much more complicated in the not distant future.     

Global theory and the nature of risk, Part I. How orthodox managed care stifles innovation.

The growing awareness that managed care is rapidly unraveling has not only produced a good deal of alarm, but also a call for prognostications regarding the future. Unfortunately, old habits die hard, and wedded ideologies die even harder. Instead of paving the way for innovation, most managed care pundits refuse to read the tea leaves properly and acknowledge that the orthodox regime is irretrievably comatose. Not understanding the fundamental flaws inherent in the old model, many persevere with rehashed predictions that only echo the very non-starters that got us in the present jam in the first place. Managed care has so far focused its energies on integrating the wrong objects, insurance and care, with all the predictably bad effects. Part 2 of this article will explore what this means and introduce the global theory of managed care as an alternative vision. Global theory lays a new foundation based on a more sound microeconomic model of risk, bifurcated markets, global fees for integrated episodes of care, and most important of all, patient/physician sovereignty.     

Overnight Custody Arrangements,Attachment, and Adjustment Among Very Young Children

Large numbers of infants and toddlers have parents who live apart due to separation, divorce, or nonmarital/noncohabiting childbearing, yet this important topic, especially the controversial issue of frequent overnights with nonresidential parents, is understudied. The authors analyzed data from the Fragile Families and Child Wellbeing Study, a longitudinal investigation of children born to primarily low‐income, racial/ethnic minority parents that is representative of 20 U.S. cities with populations over 200,000. Among young children whose parents lived apart, 6.9% of infants (birth to age 1) and 5.3% of toddlers (ages 1 to 3) spent an average of at least 1 overnight per week with their nonresident parent. An additional 6.8% of toddlers spent 35%–70% of overnights with nonresident parents. Frequent overnights were significantly associated with attachment insecurity among infants, but the relationship was less clear for toddlers. Attachment insecurity predicted adjustment problems at ages 3 and 5, but frequent overnights were not directly linked with adjustment problems at older ages.