Deep reinforcement learning methods for automated workflow construction in large scale open distributed systems

Large-scale distributed and decentralized systems often require access to multiple services, leading to the construction of complex workflows that can be difficult to design manually. This thesis proposes to use Deep Reinforcement Learning (DRL) techniques to create the optimal workflow without human intervention. The proposed hypothesis is based on using DRL algorithms combined with various styles of encoding such as Symbolic Vector Architecture and Knowledge Graph Embeddings, to handle larger and more complex systems. The approach utilizes both hierarchical and multi-task reinforcement learning. The benefit of using DRL in workflow construction is its ability to adapt to dynamic systems, where services are continuously added or removed, and systems change in quality. Our proposed approach can learn to adapt to changes in the system and find suitable alternatives

The effect of geriatric care on health care use

Health care for older adults with chronic conditions is costly and often of suboptimal quality. The quality of health care for geriatric conditions such as dementia and incontinence may be considerably poorer than for chronic disease such as diabetes and hypertension. Geriatricians have extensive training in and experience with physical, mental, cognitive, and social issues related to aging. Many elders might benefit from geriatric care; however, the current and projected future supply of geriatricians is limited. An understanding of the use and effects of geriatric care will help to ensure that the existing supply of geriatricians is used efficiently and provide information about possible benefits of expending supply. The purpose of this dissertation is to describe the use of geriatric care, to evaluate whether geriatric care reduces emergency department use, and to determine whether geriatric care is typically used in lieu of or in combination with care from other types of physicians. Using Medicare claims data for a national sample of elders who had a recent hospitalization for acute coronary syndromes and subsequent diagnosis of a geriatric condition, we found that very few patients received geriatric care. Use of geriatric care was closely tied to metropolitan status and nursing home residency. Geriatric care was associated with reduced emergency department use for both community and nursing home residents. Geriatric consultative care was associated with a reduction in emergency department use that was not statistically different from the reduction associated with geriatric primary care. Geriatric care was associated with fewer visits to family and internal medicine physicians and in some cases with fewer visits to specialists. Although our results suggest that geriatric care reduces emergency department use, the total clinical impact of geriatric care is likely to be very small because of the low supply of geriatricians. Because of the lack of existing literature on the topic, additional studies are needed to elucidate the use and effects of geriatric care in real-world clinical settings. However, for geriatric medicine to have a population-level impact on the health and health care of older adults, its focus may need to be on teaching, research, and advocacy/policymaking

Is Geriatric Care Associated with Less Emergency Department Use?

Emergency department (ED) use among seniors increased substantially in recent years. This study examined whether community and nursing home (NH) residents treated by a geriatrician were less likely to use the ED than patients treated by other physicians

Arnol'd Tongues and Quantum Accelerator Modes

The stable periodic orbits of an area-preserving map on the 2-torus, which is formally a variant of the Standard Map, have been shown to explain the quantum accelerator modes that were discovered in experiments with laser-cooled atoms. We show that their parametric dependence exhibits Arnol'd-like tongues and perform a perturbative analysis of such structures. We thus explain the arithmetical organisation of the accelerator modes and discuss experimental implications thereof.Comment: 20 pages, 6 encapsulated postscript figure

Three-Year Outcomes of Multivessel Revascularization in Very Elderly Acute Coronary Syndrome Patients

Comparative effectiveness of interventional treatment strategies for the very elderly with acute coronary syndrome remains poorly defined due to study exclusions. Interventions include percutaneous coronary intervention (PCI), usually with stents, or coronary artery bypass grafting (CABG). The elderly are frequently directed to PCI because of provider perceptions that PCI is at therapeutic equipoise with CABG and that CABG incurs increased risk. We evaluated long-term outcomes of CABG versus PCI in a cohort of very elderly Medicare beneficiaries presenting with acute coronary syndrome

Biodiversity Conservation in the REDD

Deforestation and forest degradation in the tropics is a major source of global greenhouse gas (GHG) emissions. The tropics also harbour more than half the world's threatened species, raising the possibility that reducing GHG emissions by curtailing tropical deforestation could provide substantial co-benefits for biodiversity conservation. Here we explore the potential for such co-benefits in Indonesia, a leading source of GHG emissions from land cover and land use change, and among the most species-rich countries in the world. We show that focal ecosystems for interventions to reduce emissions from deforestation and forest degradation in Indonesia do not coincide with areas supporting the most species-rich communities or highest concentration of threatened species. We argue that inherent trade-offs among ecosystems in emission reduction potential, opportunity cost of foregone development and biodiversity values will require a regulatory framework to balance emission reduction interventions with biodiversity co-benefit targets. We discuss how such a regulatory framework might function, and caution that pursuing emission reduction strategies without such a framework may undermine, not enhance, long-term prospects for biodiversity conservation in the tropics

Society-based solutions to coral reef threats in french pacific territories

This article reviews the state of coral reefs in French Pacific territories in the context of global change (especially threats linked to climate change). We first outline the specific local characteristics, vulnerabilities, and threats faced by the coral reefs of New Caledonia, French Polynesia and Wallis and Futuna. We also emphasize local and other human communities' economic and cultural reliance on coral reefs. Secondly, we discuss the natural and anthropogenic threats facing coral reefs in French Pacific territories, and current ecological responses such as mitigation and adaptation strategies. We conclude by proposing socio-economic solutions for the Pacific region across varying scales, with a special focus on enforcement measures and socio-political issues

Evaluating the effectiveness of a rapidly adopted cardiovascular technology with administrative data: The case of drug-eluting stents for acute coronary syndromes

Instrumental variable (IV) methods can correct for unmeasured confounding when using administrative (claims) data for cardiovascular outcomes research, but difficulties identifying valid IVs have limited their use. We evaluated the safety and efficacy of drug-eluting coronary stents (DES) compared to bare metal stents (BMS) for Medicare beneficiaries with acute coronary syndromes (ACS) using the rapid uptake of DES in clinical practice as an instrument. We compared results from IV to those from propensity score matching (PSM) and multivariable regression models

Disappearing and Reappearing Differences in Drug-Eluting Stent Use by Race

Drug-eluting coronary stents (DES) rapidly dominated the marketplace in the United States after approval by the Food and Drug Administration in April 2003, but utilization rates were initially lower among African-American patients. We assess whether racial differences persisted as DES diffused into practice