Validity proof of Lazard's method for CAD construction

In 1994 Lazard proposed an improved method for cylindrical algebraic decomposition (CAD). The method comprised a simplified projection operation together with a generalized cell lifting (that is, stack construction) technique. For the proof of the method's validity Lazard introduced a new notion of valuation of a multivariate polynomial at a point. However a gap in one of the key supporting results for his proof was subsequently noticed. In the present paper we provide a complete validity proof of Lazard's method. Our proof is based on the classical parametrized version of Puiseux's theorem and basic properties of Lazard's valuation. This result is significant because Lazard's method can be applied to any finite family of polynomials, without any assumption on the system of coordinates. It therefore has wider applicability and may be more efficient than other projection and lifting schemes for CAD.Comment: 21 page

Human Capital in the Knowledge Economy : A 3-Country Case Study in Healthcare

During the present knowledge economy there appear to be labor shortages at the same time and in the same regions in which there is an excess of labor supply. Such a pattern would run counter to previous major economic disruptions, as well as questioning traditional free market economic theory of supply and demand principles. Implications for policy where there are global labor shortages along with surplus labor availability in a market economy, are significant. It will likely indicate a drag on economic growth for business sectors, for regions and perhaps globally. It would indicate an accompanying growing disparity of income. Work is important, if not central to human well-being. Changes to economic thinking, and to economic growth pertaining to work and the labor force, would change the way we look at the world. Labor market change would be a warning that political and social response is needed to address the imbalance of supply and demand. A labor supply gap is researched in healthcare occupations for India, Poland, and the U.S for a global perspective and to suggest policy implications

Resisting the truancy trap : indigenous media and school attendance in 'remote' Australia

Aboriginal and Torres Strait Islander people are mobilizing a range of media forms to reveal, resist and shift what we term ‘the truancy trap’ – a simplistic, pervasive and powerful discourse of deficit about school attendance in ‘remote’ Indigenous communities that is perpetuated by mainstream media and Australian government policy. In this article, we draw upon Engoori®, an Indigenous educational intervention and research method, which provides a framework for moving institutions, organizations, communities and individuals out of deficit and into strength-based approaches. The Engoori process is activated here to surface and challenge the deficit assumptions that set the ‘truancy trap’, and as a lens for conceptualizing Indigenous media discussion, innovation and action on school attendance. The qualitative media analysis presented here reveals how a diversity of Indigenous media has been used in different ways to build a culture of inclusivity, belonging and connection; give Indigenous people a voice and reaffirm strengths in communities. The article contributes to international scholarship on Indigenous media as tools of resilience, resistance and education.peer-reviewe

Monotherapy with major antihypertensive drug classes and risk of hospital admissions for mood disorders

Major depressive and bipolar disorders predispose to atherosclerosis, and there is accruing data from animal model, epidemiological, and genomic studies that commonly used antihypertensive drugs may have a role in the pathogenesis or course of mood disorders. In this study, we propose to determine whether antihypertensive drugs have an impact on mood disorders through the analysis of patients on monotherapy with different classes of antihypertensive drugs from a large hospital database of 525 046 patients with follow-up for 5 years. There were 144 066 eligible patients fulfilling the inclusion criteria: age 40 to 80 years old at time of antihypertensive prescription and medication exposure >90 days. The burden of comorbidity assessed by Charlson and Elixhauser scores showed an independent linear association with mood disorder diagnosis. The median time to hospital admission with mood disorder was 847 days for the 299 admissions (641 685 person-years of follow-up). Patients on angiotensin-converting enzyme inhibitors or angiotensin receptor blockers had the lowest risk for mood disorder admissions, and compared with this group, those on β-blockers (hazard ratio=2.11; [95% confidence interval, 1.12–3.98]; P=0.02) and calcium antagonists (2.28 [95% confidence interval, 1.13–4.58]; P=0.02) showed higher risk, whereas those on no antihypertensives (1.63 [95% confidence interval, 0.94–2.82]; P=0.08) and thiazide diuretics (1.56 [95% confidence interval, 0.65–3.73]; P=0.32) showed no significant difference. Overall, our exploratory findings suggest possible differential effects of antihypertensive medications on mood that merits further study: calcium antagonists and β-blockers may be associated with increased risk, whereas angiotensin-converting enzyme inhibitors and angiotensin receptor blockers may be associated with a decreased risk of mood disorders

SteinerNet: a web server for integrating ‘omic’ data to discover hidden components of response pathways

High-throughput technologies including transcriptional profiling, proteomics and reverse genetics screens provide detailed molecular descriptions of cellular responses to perturbations. However, it is difficult to integrate these diverse data to reconstruct biologically meaningful signaling networks. Previously, we have established a framework for integrating transcriptional, proteomic and interactome data by searching for the solution to the prize-collecting Steiner tree problem. Here, we present a web server, SteinerNet, to make this method available in a user-friendly format for a broad range of users with data from any species. At a minimum, a user only needs to provide a set of experimentally detected proteins and/or genes and the server will search for connections among these data from the provided interactomes for yeast, human, mouse, Drosophila melanogaster and Caenorhabditis elegans. More advanced users can upload their own interactome data as well. The server provides interactive visualization of the resulting optimal network and downloadable files detailing the analysis and results. We believe that SteinerNet will be useful for researchers who would like to integrate their high-throughput data for a specific condition or cellular response and to find biologically meaningful pathways. SteinerNet is accessible at http://fraenkel.mit.edu/steinernet.National Institutes of Health (U.S.) (U54-CA112967)National Institutes of Health (U.S.) (R01-GM089903)National Science Foundation (Award Number DB1-0821391)National Institutes of Health (U.S.) (U54-CA112967

Design of Mobile Dialysis Treatment

This project developed a mobile dialysis vehicle that is fully equipped to treat six patients per day before restocking of supplies is required. The modular vehicle, built on a Ford F-750 chassis, provides a secondary dialysis treatment option for patients who are unable to access traditional dialysis facilities due to long travel distances or natural disasters. The importance and functions of dialysis treatments are established. The design, components, and layout of the vehicle operations are described