Workflow in Clinical Trial Sites & Its Association with Near Miss Events for Data Quality: Ethnographic, Workflow & Systems Simulation

10.1371/journal.pone.0039671PLoS ONE76

System Dynamics to Model the Unintended Consequences of Denying Payment for Venous Thromboembolism after Total Knee Arthroplasty

Background: The Hospital Acquired Condition Strategy (HACS) denies payment for venous thromboembolism (VTE) after total knee arthroplasty (TKA). The intention is to reduce complications and associated costs, while improving the quality of care by mandating VTE prophylaxis. We applied a system dynamics model to estimate the impact of HACS on VTE rates, and potential unintended consequences such as increased rates of bleeding and infection and decreased access for patients who might benefit from TKA. Methods and Findings: The system dynamics model uses a series of patient stocks including the number needing TKA, deemed ineligible, receiving TKA, and harmed due to surgical complication. The flow of patients between stocks is determined by a series of causal elements such as rates of exclusion, surgery and complications. The number of patients harmed due to VTE, bleeding or exclusion were modeled by year by comparing patient stocks that results in scenarios with and without HACS. The percentage of TKA patients experiencing VTE decreased approximately 3-fold with HACS. This decrease in VTE was offset by an increased rate of bleeding and infection. Moreover, results from the model suggest HACS could exclude 1.5% or half a million patients who might benefit from knee replacement through 2020. Conclusion: System dynamics modeling indicates HACS will have the intended consequence of reducing VTE rates. However, an unintended consequence of the policy might be increased potential harm resulting from over administration of prophylaxis, as well as exclusion of a large population of patients who might benefit from TKA

Relativistic Binaries in Globular Clusters

Galactic globular clusters are old, dense star systems typically containing 10\super{4}--10\super{7} stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of hard binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct {\it N}-body integrations and Fokker--Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.Comment: 88 pages, 13 figures. Submitted update of Living Reviews articl

Free histidine as a metal chelator in plants that accumulate nickel

A number of terrestrial plants accumulate large quantities of metals such as zinc, manganese, nickel, cobalt and copper in their shoots. The largest group of these so called 'metal hyperaccumulators' is found in the genus Alyssum, in which nickel concentrations can reach 3% of leaf dry biomass. Apart from their intrinsic interest, plants exhibiting this trait could be of value in the decontamination of metal polluted soils. However, the biochemical basis of the capacity for metal accumulation has not been elucidated. Here we report that exposing hyperaccumulator species of Alyssum to nickel elicits a large and proportional increase in the levels of free histidine, which is shown to be coordinated with nickel in vivo. Moreover, supplying histidine to a non-accumulating species greatly increases both its nickel tolerance and capacity for nickel transport to the shoot, indicating that enhanced production of histidine is responsible for the nickel hyperaccumulation phenotype in Alyssum

Element Case Studies: Cobalt

International audienceCobalt is economically considered as a critical metal. The main known Co ore deposits are found in the Katanga Copperbelt (Democratic Republic of Congo) where a high richness of Cu-Co tolerant and accumulator plants have developed. Cobalt mining has disseminated and disseminates large quantities of wastes in the environment and becomes a major environmental issue. Reduction of environmental risks and Co dispersion can be performed by phytoremediation and/or agromining, using trace element tolerant and putative hyperaccumulator plants originated from the biodiversity of natural Co/Cu-enriched habitats. Accumulation of foliar Co to >300 μg g-1 is exceptionally rare globally, and known principally from the Copperbelt of Central Africa. This chapter highlights advances on Co accumulation in plants, examines the potential of a Co accumulator in agromining, and defines perspectives for Co agromining by designing multi-functions and services of agroecosystems by a functional plant traits approach

Element Case Studies: Cobalt and Copper

International audienceCobalt is economically considered as a critical metal. The main known Co ore deposits are found in the Katanga Copperbelt (Democratic Republic of Congo) where a high richness of Cu-Co tolerant and accumulator plants have developed. Cobalt mining has disseminated and disseminates large quantities of wastes in the environment and becomes a major environmental issue. Reduction of environmental risks and Co dispersion can be performed by phytoremediation and/or agromining, using trace element tolerant and putative hyperaccumulator plants originated from the biodiversity of natural Co/Cu-enriched habitats. Accumulation of foliar Co to >300 μg g-1 is exceptionally rare globally, and known principally from the Copperbelt of Central Africa. This chapter highlights advances on Co accumulation in plants, examines the potential of a Co accumulator in agromining, and defines perspectives for Co agromining by designing multi-functions and services of agroecosystems by a functional plant traits approach