760 research outputs found

    Constrained dynamics of localized excitations causes a non-equilibrium phase transition in an atomistic model of glass formers

    Full text link
    Dynamic facilitation theory assumes short-ranged dynamic constraints to be the essential feature of supercooled liquids and draws much of its conclusions from the study of kinetically constrained models. While deceptively simple, these models predict the existence of trajectories that maintain a high overlap with their initial state over many structural relaxation times. We use molecular dynamics simulations combined with importance sampling in trajectory space to test this prediction through counting long-lived particle displacements. For observation times longer than the structural relaxation time exponential tails emerge in the probability distribution of this number. Reweighting trajectories towards low mobility corresponds to a phase transition into an inactive phase. While dynamics in these two phases is drastically different structural measures show only slight differences. We discuss the choice of dynamic order parameter and give a possible explanation for the microscopic origin of the effective dynamic constraints.Comment: revised versio

    Advisor Induced demand and Moral Hazard in the Third-Party Payor System

    Get PDF
    Health-care consumption in the United States has risen from 5.2% in 1960 to 17.8% of 2009 Gross Domestic Product (GDP) creating a burden that will soon be too heavy for the economy to bear. This paper proposes that the primary accelerants of health-care expenditures result from the third-party payer system that emerged in the 1950s. These corporate benefits and government subsidies, when overlaid on the traditional health-care model, have led to sustained increases in the production, recommendation, and consumption of health care while magnifying the moral hazard problem inherent in health insurance

    Humanitarianism's Contested Culture in War Zones

    Get PDF
    Humanitarians are no longer simply seen as selfless angels. Their motivations and mastery, their principles and products are questioned from within and from without. Understanding the ongoing transformations in contemporary humanitarianism requires examining the nature and evolution of humanitarian culture away from an agreed culture of cooperation to a contested one of competition. The latter reflects militarization, politicization, and marketization. What is required is a learning culture for practitioners and a consequentialist ethics more oriented to responsible reflection than rapid reaction

    Crisis Decision-Making During Hurricane Sandy: An Analysis of Established and Emergent Disaster Response Behaviors in the New York Metro Area

    Get PDF
    Objective This collective case study examined how and why specific organizational decision-making processes transpired at 2 large suburban county health departments in lower New York State during their response to Hurricane Sandy in 2012. The study also examined the relationships that the agencies developed with other emerging and established organizations within their respective health systems. Methods In investigating these themes, the authors conducted in-depth, one-on-one interviews with 30 senior-level public health staff and first responders; reviewed documentation; and moderated 2 focus group discussions with 17 participants. Results Although a natural hazard such as a hurricane was not an unexpected event for these health departments, they nevertheless confronted a number of unforeseen challenges during the response phase: prolonged loss of power and fuel, limited situational awareness of the depth and breadth of the storm’s impact among disaster-exposed populations, and coordination problems with a number of organizations that emerged in response to the disaster. Conclusions Public health staff had few plans or protocols to guide them and often found themselves improvising and problem-solving with new organizations in the context of an overburdened health care system

    Resolving Orbital and Climate Keys of Earth and Extraterrestrial Environments with Dynamics 1.0: A General Circulation Model for Simulating the Climates of Rocky Planets

    Full text link
    Resolving Orbital and Climate Keys of Earth and Extraterrestrial Environments with Dynamics (ROCKE-3D) is a 3-Dimensional General Circulation Model (GCM) developed at the NASA Goddard Institute for Space Studies for the modeling of atmospheres of Solar System and exoplanetary terrestrial planets. Its parent model, known as ModelE2 (Schmidt et al. 2014), is used to simulate modern and 21st Century Earth and near-term paleo-Earth climates. ROCKE-3D is an ongoing effort to expand the capabilities of ModelE2 to handle a broader range of atmospheric conditions including higher and lower atmospheric pressures, more diverse chemistries and compositions, larger and smaller planet radii and gravity, different rotation rates (slowly rotating to more rapidly rotating than modern Earth, including synchronous rotation), diverse ocean and land distributions and topographies, and potential basic biosphere functions. The first aim of ROCKE-3D is to model planetary atmospheres on terrestrial worlds within the Solar System such as paleo-Earth, modern and paleo-Mars, paleo-Venus, and Saturn's moon Titan. By validating the model for a broad range of temperatures, pressures, and atmospheric constituents we can then expand its capabilities further to those exoplanetary rocky worlds that have been discovered in the past and those to be discovered in the future. We discuss the current and near-future capabilities of ROCKE-3D as a community model for studying planetary and exoplanetary atmospheres.Comment: Revisions since previous draft. Now submitted to Astrophysical Journal Supplement Serie

    The Ursinus Weekly, April 17, 1908

    Get PDF
    Baseball • The Dean\u27s column • The young ladies entertain • Benefit social • Schaff prize debate • Literary societies • Second team game • College world • Personals • Literary Supplement: St. Valentine at Olevia; An adventure; Eugene Field; The present financial crisis; Railway rate regulation; James Russel Lowellhttps://digitalcommons.ursinus.edu/weekly/2904/thumbnail.jp

    The accuracy of a river bed moulding/casting system and the effectiveness of a low-cost digital camera for recording river bed fabric

    Get PDF
    Digital photogrammetry has been used to develop and test an artificial river bed moulding and casting system, which allows the pebbles within a coarse grain river bed to be recreated for hydraulic research in a laboratory flow channel or flume. Imagery of both the original streambed and the cast facsimile was acquired using a non-metric Kodak DCS460 digital camera and digital elevation models and orthophotographs were derived and compared to assess the accuracy of the moulding and casting system. These comparative tests proved to be critical in modifying and developing the system. Additional imagery was obtained in the field using a non-metric Olympus C3030 “compact” digital camera to assess whether far cheaper camera technology could deliver data appropriate for such comparative examinations. Internal calibration parameter sets and data that were generated were compared with data obtained by the non-metric Kodak DCS460. These tests demonstrate that digital sensors built around highquality 35 mm professional camera bodies and lenses are required for comparative examinations and for similar system development
    corecore