The pickup and delivery problem: Faces and branch-and-cut algorithm

This paper formulates the pickup and delivery problem, also known as the dial-a-ride problem, as an integer program. Its polyhedral structure is explored and four classes of valid inequalities developed. The results of a branch-and-cut algorithm based on these constraints are presented.     

The dieting maelstrom: Is it possible and advisable to lose weight?

An impassioned debate over the virtues and dangers of dieting is polarizing the field and diverts attention from key issues. Dieting clearly has costs and, for some, has the potential for benefit. The primary challenges are (1) to identify individuals who will be helped or harmed by dieting, (2) to reduce the frequency and severity of dieting in those for whom the costs exceed the benefits, (3) to better understand the physiological and psychological reasons why some people can lose and others cannot, and (4) to develop safe and effective means for weight loss and its maintenance and to target these methods to individuals who stand to benefit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Study of the Radiolysis Products of the Tri-n-Butyl-Phosphate–Isopar-M–HNO3 System before and after Regeneration with Carbonates of Organic Bases

Protection of Metals and Physical Chemistry of Surfaces - By measuring the hydrodynamic characteristics (viscosity, density of extraction mixture, and interfacial tension) and determining the...     

Thermal Stability of KU-2*8 Sulfocation Exchanger in Contact with Nitric Acid under Isochoric Conditions

Protection of Metals and Physical Chemistry of Surfaces - The thermal stability of KU-2*8 cation exchanger mixed with 4 and 12 mol/L nitric acids is studied via differential scanning calorimetry...     

An Isolated Mode I Three-Dimensional Planar Crack: The Stress Intensity Factor is Independent of The Elastic Constants

It is demonstrated that for an isolated Mode I planar crack embedded in an infinite body, the stress intensity factor along the crack front is a function independent of the elastic constants.     

Sensitization of luminescence of wurtzite GaN crystals doped with Eu and the additionally introduced Zn impurity

A possibility to increase the intensity of intracenter transitions of the Eu ion in GaN crystals is investigated via introduction of the additional impurity to vary the local environment of the rare-earth ion. Wurtzite p-GaN crystals were initially doped with Mg and then with Eu. The introduction of the additional Zn impurity leads to a significant increase in the photoluminescence intensity in the range 3580–4250 Å and the long-wavelength spectral range 5400–6237 Å. This phenomenon can be attributed to the manifestation of sensitization of luminescence of optically active intracenter f-f transitions of the Eu³⁺ ion due to the introduction of the additional impurity, which promotes the formation of complexes of the rare-earth ion with a large capture cross-section of charge carriers.     

Women's changing work roles: Impact on health, family, and public policy.

Women's work roles have changed enormously. This article describes the long-term and short-term changes in women's paid employment. It also introduces a set of Public Forum articles that discuss the consequences of these changes for women's health and for their families and delineate the government's responses to women's changing work roles. The impetus for this Public Forum section came from a workshop conducted under the auspices of the John D. and Catherine T. MacArthur Foundation Network on the Determinants and Consequences of Health-Promoting and Health-Damaging Behaviors. Therefore, the article also discusses the mission of the Network and why multidisciplinary, collaborative research on the effects of women's employment is vital. (PsycINFO Database Record (c) 2010 APA, all rights reserved)