774 research outputs found
Constrained dynamics of localized excitations causes a non-equilibrium phase transition in an atomistic model of glass formers
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
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
Dial 911 for Murder: The Impact of Emergency Response Time on Homicides
Several theories have been offered to explain the recent declines in violent crime rates in the United States. We hypothesize that technological innovations, which improved information transmission and shortened the response time between an aggravated assault incident and treatment, reduced the cost of saving lives and caused much of the decline in homicide rates in recent decades. Using difference-in-differences and event studies, we show that improvements in emergency services (9-1-1) caused significant decreases in homicide rates. Various falsification tests support these findings
Humanitarianism's Contested Culture in War Zones
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
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
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Measles vaccination and antibody response in autism spectrum disorder
OBJECTIVE: To test the hypothesis that measles vaccination was involved in the pathogenesis of autism spectrum disorders (ASD) as evidenced by signs of a persistent measles infection or abnormally persistent immune response shown by circulating measles virus or raised antibody titres in children with ASD who had been vaccinated against measles, mumps and rubella (MMR) compared with controls. DESIGN: Case-control study, community based. METHODS: A community sample of vaccinated children aged 10-12 years in the UK with ASD (n = 98) and two control groups of similar age, one with special educational needs but no ASD (n = 52) and one typically developing group (n = 90), were tested for measles virus and antibody response to measles in the serum. RESULTS: No difference was found between cases and controls for measles antibody response. There was no dose-response relationship between autism symptoms and antibody concentrations. Measles virus nucleic acid was amplified by reverse transcriptase-PCR in peripheral blood mononuclear cells from one patient with autism and two typically developing children. There was no evidence of a differential response to measles virus or the measles component of the MMR in children with ASD, with or without regression, and controls who had either one or two doses of MMR. Only one child from the control group had clinical symptoms of possible enterocolitis. CONCLUSION: No association between measles vaccination and ASD was shown
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
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
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
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
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