6,015 research outputs found
Fixing Food Safety: Protecting America's Food Supply From Farm-to-Fork
Provides an overview of the major concerns regarding U.S. food safety, including an ineffective regulatory system, and of food-borne disease threats. Includes lists of recent outbreaks, major causes of food-borne illnesses, and recommended solutions
Shortchanging America's Health 2008: A State-by-State Look at How Federal Public Health Dollars Are Spent
Examines public health indicators in each state, in combination with federal and state funding for programs to promote health. Includes state rankings by funding per capita, percentage of population who are uninsured, disease rates, and other indicators
Fate of global superconductivity in arrays of long SNS junctions
Normal-metal films overlaid with arrays of superconducting islands undergo
Berezinskii-Kosterlitz-Thouless (BKT) superconducting transitions at a
temperature . We present measurements of T for arrays of
mesoscopic Nb islands patterned on Au films for a range of island spacings .
We show that , and explain this dependence in terms of the
quasiclassical prediction that the Thouless energy, rather than the
superconducting gap, governs the inter-island coupling. We also find two
deviations from the quasiclassical theory: (i) is sensitive to island
height, because the islands are mesoscopic; and (ii) for widely spaced islands
the transition appears to lead, not to a superconducting state, but to a
finite-resistance "metallic" one.Comment: 12 pages, 4 figure
Complete information pivotal-voter model with asymmetric group size
We study the equilibria of the standard pivotal-voter participation game between two groups of voters of asymmetric sizes (majority and minority), as originally proposed by Palfrey and Rosenthal (Public Choice 41(1):7–53, 1983). We find a unique equilibrium wherein the minority votes with certainty and the majority votes with probability in (0,1); we prove that this is the only equilibrium in which voters of only one group play a pure strategy, and we provide sufficient conditions for its existence. Equilibria where voters of both groups vote with probability in (0, 1) are analyzed numerically
Complete information pivotal-voter model with asymmetric group size and asymmetric benefits
We analyse a standard pivotal-voter model under majority rule, with two rival groups of players, each preferring one of two public policies and simultaneously deciding whether to cast a costly vote, as in Palfrey and Rosenthal (1983). We allow the benefit of the favorite public policy to differ across groups and impose an intuitive refinement, namely that voting probabilities are continuous in the cost of voting to pin down a unique equilibrium. The unique continuous equilibrium depends on a key threshold that compares the sizes of the two groups
Statistical analysis of Ni nanowires breaking processes: a numerical simulation study
A statistical analysis of the breaking behavior of Ni nanowires is presented.
Using molecular dynamic simulations, we have determined the time evolution of
both the nanowire atomic structure and its minimum cross section (Sm(t)).
Accumulating thousands of independent breaking events, Sm histograms are built
and used to study the influence of the temperature, the crystalline stretching
direction and the initial nanowire size. The proportion of monomers, dimers and
more complex structures at the latest stages of the breaking process are
calculated, finding important differences among results obtained for different
nanowire orientations and sizes. Three main cases have been observed. (A) [111]
stretching direction and large nanowire sizes: the wire evolves from more
complex structures to monomers and dimers prior its rupture; well ordered
structures is presented during the breaking process. (B) Large nanowires
stretched along the [100] and [110] directions: the system mainly breaks from
complex structures (low probability of finding monomers and dimers), having
disordered regions during their breakage; at room temperature, a huge histogram
peak around Sm=5 appears, showing the presence of long staggered pentagonal Ni
wires with ...-5-1-5-... structure. (C) Initial wire size is small: strong size
effects independently on the temperature and stretching direction. Finally, the
local structure around monomers and dimmers do not depend on the stretching
direction. These configurations differ from those usually chosen in static
studies of conductance.Comment: 18 pages, 13 figure
Ready or Not? Protecting the Public's Health From Diseases, Disasters, and Bioterrorism, 2008
Examines ten indicators to assess progress in state readiness to respond to bioterrorism and other public health emergencies. Evaluates the federal government's and hospitals' preparedness. Makes suggestions for funding, restructuring, and other reforms
Medical Implications of Space Radiation Exposure Due to Low Altitude Polar Orbits
Space radiation research has progressed rapidly in recent years, but there
remain large uncertainties in predicting and extrapolating biological responses
to humans. Exposure to cosmic radiation and Solar Particle Events may pose a
critical health risk to future spaceflight crews and can have a serious impact
to all biomedical aspects of space exploration. The relatively minimal
shielding of the cancelled 1960's Manned Orbiting Laboratory program's space
vehicle and the high inclination polar orbits would have left the crew
susceptible to high exposures of cosmic radiation and high dose-rate SPEs that
are mostly unpredictable in frequency and intensity. In this study, we have
modeled the nominal and off-nominal radiation environment that a MOL-like
spacecraft vehicle would be exposed to during a 30-day mission using high
performance, multi-core computers. Projected doses from a historically large
SPE (e.g. the August 1972 solar event) have been analyzed in the context of the
MOL orbit profile, providing an opportunity to study its impact to crew health
and subsequent contingencies.It is reasonable to presume that future
commercial, government, and military spaceflight missions in low-Earth orbit
will have vehicles with similar shielding and orbital profiles. Studying the
impact of cosmic radiation to the mission's operational integrity and the
health of MOL crewmembers provides an excellent surrogate and case-study for
future commercial and military spaceflight missions.Comment: 6 pages, 4 figures, 2 table
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