Hospital specialists' private practice and its impact on the number of NHS patients treated and on the delay for elective surgery.

This paper analyses UK NHS waiting times and waiting lists for elective surgery looking at the hospital specialists' behaviour and the conflict of interest these may face when allowed to practice privately. We look at the relationship between the government as the health care purchaser and principal of a two-tier hierarchy, and two hospital specialists, the agents, that deal with elective and emergency treatement. Specialists are organised in a separated structure, each responsible for only one type of surgery (either elective or emergency). We formalise specialists' preferences when dealing with the two activities. We see how specialists' interest in the income obtained with private practice (and altruism) affects negatively (positively) the optimal NHS numbers treated and increases the waiting time for elective surgery. Asymmetry of information also has a negative impact on the NHS leading to fewer patients treated or higher transfers paid. If remuneration is based on performance, transfers have to take private practice into account. As a result, there may be benefits from extra investment so as to improve information systems as well as seeking out instruments for nurturing more altruistic behaviour on the part of the specialistswaiting times and lists; elective surgery; hospital specialists

La Cultura Cura/Culture Heals

A research project on how Native American practices and values strengthen coping with life stressors

Improved rapid transit network design model: considering transfer effects

The rail rapid transit network design problem aims at locating train alignments and stations, maximizing demand coverage while competing with the current existing networks. We present a model formulation for computing tight bounds of the linear relaxation of the problem where transfers are also introduced. The number of transfers within a trip is a decisive attribute for attracting passengers: transferring is annoying and undesirable for passengers. We conduct computational experiments on different networks and show how we are able to solve more efficiently problems that have been already solved; sensitivity analysis on several model parameters are also performed so as to demonstrate the robustness of the new formulation

Chloride Penetration in Circular Concrete Columns

Most of the diffusion models of chloride ions in reinforced concrete (RC) elements proposed in literature are related to an isotropic homogeneous semi-infinite medium. This assumption reduces the mathematical complexity, but it is correct only for plane RC elements. This work proposes a comparison between the diffusion model of chloride ions in RC circular columns and in RC slab elements. The durability of RC cylindric elements estimated with the circular model instead of the plane model is shown to be shorter. Finally, a guideline is formulated to properly use the standard and more simple plane model instead of the circular one to estimate the time to corrosion initiation of cylindrical RC elements

Integration of Timetable Planning and Rolling Stock in Rapid Transit Networks

The aim of this paper is to propose an integrated planning model to adequate the offered capacity and system frequencies to attend the increased passenger demand and traffic congestion around urban and suburban areas. The railway capacity is studied in line planning, however, these planned frequencies were obtained without accounting for rolling stock flows through the rapid transit network. In order to provide the problem more freedom to decide rolling stock flows and therefore better adjusting these flows to passenger demand, a new integrated model is proposed, where frequencies are readjusted. Then, the railway timetable and rolling stock assignment are also calculated, where shunting operations are taken into account. These operations may sometimes malfunction, causing localized incidents that could propagate throughout the entire network due to cascading effects. This type of operations will be penalized with the goal of selectively avoiding them and ameliorating their high malfunction probabilities. Swapping operations will also be ensured using homogeneous rolling stock material and ensuring parkings in strategic stations. We illustrate our model using computational experiments drawn from RENFE (the main Spanish operator of suburban passenger trains) in Madrid, Spain. The results show that through this integrated approach a greater robustness degree can be obtaine

Improved rapid transit network design model: considering transfer effects

The rail rapid transit network design problem aims at locating train alignments and stations, maximizing demand coverage while competing with the current existing networks. We present a model formulation for computing tight bounds of the linear relaxation of the problem where transfers are also introduced. The number of transfers within a trip is a decisive attribute for attracting passengers: transferring is annoying and undesirable for passengers. We conduct computational experiments on different networks and show how we are able to solve more efficiently problems that have been already solved; sensitivity analysis on several model parameters are also performed so as to demonstrate the robustness of the new formulation