1,503 research outputs found
Single molecule photon counting statistics for quantum mechanical chromophore dynamics
We extend the generating function technique for calculation of single
molecule photon emission statistics [Y. Zheng and F. L. H. Brown, Phys. Rev.
Lett., 90,238305 (2003)] to systems governed by multi-level quantum dynamics.
This opens up the possibility to study phenomena that are outside the realm of
purely stochastic and mixed quantum-stochastic models. In particular, the
present methodology allows for calculation of photon statistics that are
spectrally resolved and subject to quantum coherence. Several model
calculations illustrate the generality of the technique and highlight
quantitative and qualitative differences between quantum mechanical models and
related stochastic approximations. Calculations suggest that studying photon
statistics as a function of photon frequency has the potential to reveal more
about system dynamics than the usual broadband detection schemes.Comment: Submitted to the Journal of Physical Chemistr
A DISTRIBUTIONAL ANALYSIS OF THE COSTS OF FOODBORNE ILLNESS: WHO ULTIMATELY PAYS?
This paper traces the economic impact of the costs of foodborne illness on the U.S. economy using a Social Accounting Matrix (SAM) framework. Previous estimates of the costs of seven foodborne pathogens are disaggregated by type, and distributed across the population using data from the National Health Interview Survey. Initial income losses resulting from premature death cause a decrease in economic activity. Medical costs, in contrast, result in economic growth, though this growth does not outweigh the total costs of premature death. A SAM accounting of how the costs of illness are diffused through the economy provides useful information for policy makers.Cost of illness, Foodborne illness, Social Accounting Matrix, Food Consumption/Nutrition/Food Safety,
FOOD SAFETY INNOVATION IN THE UNITED STATES: EVIDENCE FROM THE MEAT INDUSTRY
Recent industry innovations improving the safety of the Nation's meat supply range from new pathogen tests, high-tech equipment, and supply chain management systems, to new surveillance networks. Despite these and other improvements, the market incentives that motivate private firms to invest in innovation seem to be fairly weak. Results from an ERS survey of U.S. meat and poultry slaughter and processing plants and two case studies of innovation in the U.S. beef industry reveal that the industry has developed a number of mechanisms to overcome that weakness and to stimulate investment in food safety innovation. Industry experience suggests that government policy can increase food safety innovation by reducing informational asymmetries and strengthening the ability of innovating firms to appropriate the benefits of their investments.Food safety, innovation, meat, asymmetric information, Beef Steam Pasteurization System, Bacterial Pathogen Sampling and Testing Program, Food Consumption/Nutrition/Food Safety, Livestock Production/Industries,
TRACEABILITY IN THE U.S. FOOD SUPPLY: ECONOMIC THEORY AND INDUSTRY STUDIES
This investigation into the traceability baseline in the United States finds that private sector food firms have developed a substantial capacity to trace. Traceability systems are a tool to help firms manage the flow of inputs and products to improve efficiency, product differentiation, food safety, and product quality. Firms balance the private costs and benefits of traceability to determine the efficient level of traceability. In cases of market failure, where the private sector supply of traceability is not socially optimal, the private sector has developed a number of mechanisms to correct the problem, including contracting, third-party safety/quality audits, and industry-maintained standards. The best-targeted government policies for strengthening firms' incentives to invest in traceability are aimed at ensuring that unsafe of falsely advertised foods are quickly removed from the system, while allowing firms the flexibility to determine the manner. Possible policy tools include timed recall standards, increased penalties for distribution of unsafe foods, and increased foodborne-illness surveillance.traceability, tracking, traceback, tracing, recall, supply-side management, food safety, product differentiation, Food Consumption/Nutrition/Food Safety, Industrial Organization,
GABA Withdrawal Modifies Network Activity in Cultured Hippocampal Neurons
Dissociated hippocampal neurons, grown
in culture for 2 to 3 weeks, tended to fire
bursts of synaptic currents at fairly regular
intervals, representing network activity. A
brief exposure of cultured neurons to GABA
caused a total suppression of the spontaneous
network activity. Following a washout of
GABA, the activity was no longer clustered in
bursts and instead, the cells fired at a high
rate tonic manner. The effect of removing
GABA could be seen as long as 1 to 2 days
after GABA withdrawal and is expressed as
an increase in the number of active cells in a
network, as well as in their firing rates. Such
striking effects of GABA removal may
underlie part of the GABA withdrawal
syndrome seen elsewhere
Distinguishing representational geometries with controversial stimuli: Bayesian experimental design and its application to face dissimilarity judgments
Comparing representations of complex stimuli in neural network layers to
human brain representations or behavioral judgments can guide model
development. However, even qualitatively distinct neural network models often
predict similar representational geometries of typical stimulus sets. We
propose a Bayesian experimental design approach to synthesizing stimulus sets
for adjudicating among representational models efficiently. We apply our method
to discriminate among candidate neural network models of behavioral face
dissimilarity judgments. Our results indicate that a neural network trained to
invert a 3D-face-model graphics renderer is more human-aligned than the same
architecture trained on identification, classification, or autoencoding. Our
proposed stimulus synthesis objective is generally applicable to designing
experiments to be analyzed by representational similarity analysis for model
comparison
Non-Life Insurance Pricing: Multi Agents Model
We use the maximum entropy principle for pricing the non-life insurance and
recover the B\"{u}hlmann results for the economic premium principle. The
concept of economic equilibrium is revised in this respect.Comment: 6 pages, revtex
Final State Interactions Effects in Neutrino-Nucleus Interactions
Final State Interactions effects are discussed in the context of Monte Carlo
simulations of neutrino-nucleus interactions. A role of Formation Time is
explained and several models describing this effect are compared. Various
observables which are sensitive to FSI effects are reviewed including
pion-nucleus interaction and hadron yields in backward hemisphere. NuWro Monte
Carlo neutrino event generator is described and its ability to understand
neutral current production data in GeV neutrino flux
experiments is demonstrated.Comment: 13 pages, 16 figure
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