Locally Complete Path Independent Choice Functions and Their Lattices

The concept of path independence (PI) was first introduced by Arrow (1963) as a defense of his requirement that collective choices be rationalized by a weak ordering. Plott (1973) highlighted the dynamic aspects of PI implicit in Arrow's initial discussion. Throughout these investigations two questions, both initially raised by Plott, remained unanswered. What are the precise mathematical foundations for path independence? How can PI choice functions be constructed? We give complete answers to both these questions for finite domains and provide necessary conditions for infinite domains. We introduce a lattice associated with each PI function. For finite domains these lattices coincide with locally lower distributive or meet-distributive lattices and uniquely characterize PI functions. We also present an algorithm, effective and exhaustive for finite domains, for the construction of PI choice functions and hence for all finite locally lower distributive lattices. For finite domains, a PI function is rationalizable if and only if the lattice is distributive. The lattices associated with PI functions that satisfy the stronger condition of the weak axiom of revealed preference are chains of Boolean algebras and conversely. Those that satisfy the strong axiom of revealed preference are chains and conversely.

FOOD STAMPS: PROGRAM PARAMETERS AND STANDARDS OF LIVING FOR LOW-INCOME HOUSEHOLDS

Food Security and Poverty,

Design and Development of an Affordable Haptic Robot with Force-Feedback and Compliant Actuation to Improve Therapy for Patients with Severe Hemiparesis

The study describes the design and development of a single degree-of-freedom haptic robot, Haptic Theradrive, for post-stroke arm rehabilitation for in-home and clinical use. The robot overcomes many of the weaknesses of its predecessor, the TheraDrive system, that used a Logitech steering wheel as the haptic interface for rehabilitation. Although the original TheraDrive system showed success in a pilot study, its wheel was not able to withstand the rigors of use. A new haptic robot was developed that functions as a drop-in replacement for the Logitech wheel. The new robot can apply larger forces in interacting with the patient, thereby extending the functionality of the system to accommodate low-functioning patients. A new software suite offers appreciably more options for tailored and tuned rehabilitation therapies. In addition to describing the design of the hardware and software, the paper presents the results of simulation and experimental case studies examining the system\u27s performance and usability

An alternate method for achieving temperature control in the -130 C to 75 C range

Thermal vacuum testing often requires temperature control of chamber shrouds and heat exchangers within the -130 C to 75 C range. There are two conventional methods which are normally employed to achieve control through this intermediate temperature range: (1) single-pass flow where control is achieved by alternately pulsing hot gaseous nitrogen (GN2) and cold LN2 into the feed line to yield the setpoint temperature; and (2) closed-loop circulation where control is achieved by either electrically heating or LN2 cooling the circulating GN2 to yield the setpoint temperature. A third method, using a mass flow ratio controller along with modulating control valves on GN2 and LN2 lines, provides excellent control but equipment for this method is expensive and cost-prohibitive for all but long-term continuous processes. The single-pass method provides marginal control and can result in unexpected overcooling of the test article from even a short pulse of LN2. The closed-loop circulation method provides excellent control but requires an expensive blower capable of operating at elevated pressures and cryogenic temperatures. Where precise control is needed (plus or minus 2 C), single-pass flow systems typically have not provided the precision required, primarily because of overcooling temperature excursions. Where several individual circuits are to be controlled at different temperatures, the use of expensive cryogenic blowers for each circuit is also cost-prohibitive, especially for short duration of one-of-a-kind tests. At JPL, a variant of the single-pass method was developed that was shown to provide precise temperature control in the -130 C to 75 C range while exhibiting minimal setpoint overshoot during temperature transitions. This alternate method uses a commercially available temperature controller along with a GN2/LN2 mixer to dampen the amplitude of cold temperature spikes caused by LN2 pulsing. The design of the GN2/LN2 mixer, the overall control system configuration, the operational procedure, and the prototype system test results are described

Missing in Action? Electronic Gaming Machines in Gambling Studies Research

In the past thirty years casinos across the world have become dominated by the rise of “electronic gaming machines” (EGMs). Expanding with tremendous speed, this technology has arguably become the dominant form of non-online gambling around the world at time of writing (DeMichele, 2017; Schwartz, 2018). EGMs are also noted as being one of the most harmful forms of gambling, with significant numbers of players betting beyond their financial limits (MacLaren et al, 2012; Stewart & Wohl, 2013), spending a disproportionate amount of time playing (Cummings, 1999; Ballon, 2005; Schüll, 2012; cf. Dickerson, 1996), becoming disconnected from the world outside of the “zone” (Schüll, 2012) of gambling play, and even becoming bankrupt or otherwise financially crippled as a result of their use (Petry, 2003; Scarf et al, 2011). Using metadata from Web of Science and Scopus databases, we analysed peer-reviewed gambling research produced in Australia, New Zealand, North America and the UK published between 1996 and 2016. Surprisingly, we found that the overwhelming of majority of articles do not specifically address EGMs as the most popular and pervasive gambling technology available. Our paper teases out some concerning implications of this finding for the interdisciplinary field of gambling studies

The unavoidable costs of ethnicity : a review of evidence on health costs

This report was commissioned by the Advisory Committee on Resource Allocation (ACRA), and prepared by the Centre for Health Services Studies (CHESS) and the Centre for Research in Ethnic Relations (CRER) at the University of Warwick. The NHS Executive does not necessarily assent to the factual accuracy of the report, nor necessarily share the opinions and recommendations of the authors. The study reviews the evidence concerning the degree to which the presence of populations of minority ethnic origin was associated with ‘unavoidable additional costs’ in health service delivery. While local health authorities retail full autonomy in their use of funds allocated to them under the Hospital and Community Health Services formula, the size of that budget is governed by a set of weightings applied to their population, to allow for factors known to influence levels of need, and the costs of providing services. The study began by considering the definitions used in describing ‘ethnicity’ and ethnic groups in relevant medical and social policy literature. It is clear that no fixed set of terms can be adopted, and that flexibility is required to respond to social changes. The terms used in the 1991 Census, with additions to allow for local and contemporary developments, provide a suitable baseline but require additional information on religion language and migration history for clinical and health service delivery planning. There have been notable developments in health service strategy to meet the needs of black and minority ethnic groups which have been encouraged by good practice guidelines and local initiatives. Together with research into epidemiology and ethnic monitoring of services, these have enlarged understanding of the impact of diversity. A conceptual model is developed which explores the potential for such diversity to lead to variations in the cost of providing health services to a multi-ethnic population. The research team reviewed the existing published evidence relating to ethnic health and disease treatment in medical, social science, academic and practitioner literature, using conventional techniques. Additional evidence was located through trawls of ‘grey’ literature in specialist collections, and through contacting all English health districts with a request for information. A number of authorities and trusts provided written and oral evidence, and a bibliography of key materials is provided. Key issues considered include the need for and use of, interpreter and translation services, the incidence of ‘ethnically-specific’ disease, and variations in the prevalence and cost of treating ‘common’ conditions in minority ethnic populations. Sources of variation are discussed, and a ‘scoping’ approach adopted to explore the extent to which these variations could be adequately modelled. It is clear that while some additional costs can be identified, and seen to be unavoidable, there are other areas where the presence of minority populations may lead to lessened pressures on budgets, or where provision of ‘ethnic-specific’ facilities may be alternative to existing needs. The literature provides a range of estimates which can be used in a modelling exercise, but is deficient in many respects, particularly in terms of precise costs associated with procedure and conditions, or in associating precise and consistent categories of ethnic group with epidemiological and operational service provision data. Certain other activities require funding to set them up, and may not be directly related to population size. There is considerable variation in the approaches adopted by different health authorities, and many services are provided by agencies not funded by NHS budgets. The study was completed before the announcement of proposed changes in health service commissioning which may have other implications for ethnic diversity. The presence of minorities is associated with the need to provide additional services in respect of interpreting and translation, and the media of communication. In order to achieve clinical effectiveness, a range of advocacy support facilities or alternative models of provision seem to be desirable. Ethnic diversity requires adaptation and additional evidence in order to inform processes of consultation and commissioning. Minority populations do create demands for certain additional specific clinical services not required by the bulk of the majority population: it is not yet clear to what extent the reverse can be stated since research on ‘under-use’ is less well developed. Some variations in levels of need, particularly those relating to established clinical difference in susceptibility or deprivation, are already incorporated in funding formulae although it is not clear how far the indicators adequately reflect these factors. Costs are not necessarily simply related to the size of minority populations. The provision of services to meet minority needs is not always a reflection of their presence, but has frequently depended upon the provision of additional specific funds. There is a consensus that the NHS research and development strategy should accept the need for more work to establish the actual levels of need and usage of service by ethnic minority groups, and that effort should be made to use and improve the growing collection of relevant information through ethnic monitoring activities. A variety of modelling techniques are suggested, and can be shown to have the potential to provide practical guidance to future policy in the field. Current data availability at a national or regional scale is inadequate to provide estimates of the ‘additional costs of ethnicity’ but locally collected data and the existence of relevant policy initiatives suggest that a focused study in selected districts would provide sufficiently robust information to provide reliable estimates. The review has demonstrated that there are costs associated with the presence of minority ethnic groups in the population which can be shown to be unavoidable and additional, but that others are either ‘desirable’ or ‘alternative’. It would be wrong to assume that all cost pressures of this nature are in the same direction. Our study has drawn attention to deficiencies in data collection and budgeting which may hinder investigation of the effectiveness of the service in general. The process of drawing attention to ethnic minority needs itself leads to developments in services which are functional and desirable for the majority population

I\u27ve always been outspoken on what I think can be improved : An Interview with Dr. Garry J. Smith

Dr. Garry J. Smith has spent many years at the forefront of critical gambling research in Canada. In this interview he talks about the genesis of the Alberta Gambling Research Institute, how sociology brings a different lens to gambling studies than psychology, why he speaks out against certain aspects of commercial gambling, the relationship between fun and fairness, and the critical gaps in research that need to be added to address the inherent conflicts of interest that occur with self-regulated gambling. The interview was conducted by academics Fiona Nicoll and Mark R Johnson on 29 November, 2017. A transcript of the conversation was edited for publication. As part of this process, both interviewers and the interviewee were invited to edit their remarks