2,914 research outputs found
ECONOMIC BURDEN OF SALMONELLA INFECTIONS IN THE UNITED STATES
The aim of this study is to evaluate medical expenditures and lost productivity associated with burden of Salmonella infections. We used laboratory confirmed number of Salmonella cases and corresponding multipliers to estimate the burden of illness using the method adopted by Foodborne Diseases Active Surveillance Network (FoodNet) at Centers for Disease Control and Prevention (CDC). The medical costs estimates are retrospective analysis of reimbursement records from MarketScan data. We identified patients with a diagnosis of salmonellosis using ICD-9 CM codes from the MarketScan 1993-2001 databases. Productivity loss from the nonfatal cases of Salmonella was calculated using the distributions of lost workdays and household services due to the illness. Statistical value of life approach was used to estimate the costs due to premature deaths. We also compared the costs for the gastrointestinal salmonellosis to the cost for the invasive salmonellosis. Confidence intervals around the cost estimates were calculated using a Monte Carlo simulation technique. Estimated average economic burden due to Salmonella was 5,797 per inpatient with gastrointestinal infection, 4.63 million per premature death. Total economic buren due to Salmonella in the United States was estimated at 1.6 to 2,472 per case of Salmonella infection. The cost estimate is largely driven by the number of premature deaths followed by average cost of hospitalization. Defining the risk factors for fatal outcomes may help target treatment and preventive strategies.Food Consumption/Nutrition/Food Safety,
Synchronous vs Asynchronous Chain Motion in α-Synuclein Contact Dynamics
α-Synuclein (α-syn) is an intrinsically unstructured 140-residue neuronal protein of uncertain function that is implicated in the etiology of Parkinson’s disease. Tertiary contact formation rate constants in α-syn, determined from diffusion-limited electron-transfer kinetics measurements, are poorly approximated by simple random polymer theory. One source of the discrepancy between theory and experiment may be that interior-loop formation rates are not well approximated by end-to-end contact dynamics models. We have addressed this issue with Monte Carlo simulations to model asynchronous and synchronous motion of contacting sites in a random polymer. These simulations suggest that a dynamical drag effect may slow interior-loop formation rates by about a factor of 2 in comparison to end-to-end loops of comparable size. The additional deviations from random coil behavior in α-syn likely arise from clustering of hydrophobic residues in the disordered polypeptide
Bio-Lubricants production from fish oil residue by transesterification with trimethylolpropane
The fatty acid ethyl esters mixture, a fish oil residue obtained after the extraction of omega-3 polyunsaturated fatty esters, has been converted into mixtures of mono-, di-, and triesters of trimethylolpropane by transesterification at 100-140¿°C under vacuum with sodium ethoxide as catalyst. This method has shown to be more efficient than the enzymatic transesterification using commercially available lipases. The crude reaction mixture (84% conversion of ethyl esters), enriched in trimethylolpropane triesters (96% selectivity) was characterized and its properties compared with those of the starting ethyl esters mixture and the trimethylolpropane esters obtained from vegetal sources
Direct measurement of the 14N(p,g)15O S-factor
We have measured the 14N(p,g)15O excitation function for energies in the
range E_p = 155--524 keV. Fits of these data using R-matrix theory yield a
value for the S-factor at zero energy of 1.64(17) keV b, which is significantly
smaller than the result of a previous direct measurement. The corresponding
reduction in the stellar reaction rate for 14N(p,g)15O has a number of
interesting consequences, including an impact on estimates for the age of the
Galaxy derived from globular clusters.Comment: 5 pages, 3 figures, submitted to Phys. Rev. Let
Improving randomness characterization through Bayesian model selection
Nowadays random number generation plays an essential role in technology with
important applications in areas ranging from cryptography, which lies at the
core of current communication protocols, to Monte Carlo methods, and other
probabilistic algorithms. In this context, a crucial scientific endeavour is to
develop effective methods that allow the characterization of random number
generators. However, commonly employed methods either lack formality (e.g. the
NIST test suite), or are inapplicable in principle (e.g. the characterization
derived from the Algorithmic Theory of Information (ATI)). In this letter we
present a novel method based on Bayesian model selection, which is both
rigorous and effective, for characterizing randomness in a bit sequence. We
derive analytic expressions for a model's likelihood which is then used to
compute its posterior probability distribution. Our method proves to be more
rigorous than NIST's suite and the Borel-Normality criterion and its
implementation is straightforward. We have applied our method to an
experimental device based on the process of spontaneous parametric
downconversion, implemented in our laboratory, to confirm that it behaves as a
genuine quantum random number generator (QRNG). As our approach relies on
Bayesian inference, which entails model generalizability, our scheme transcends
individual sequence analysis, leading to a characterization of the source of
the random sequences itself.Comment: 25 page
Simultaneous Border-Collision and Period-Doubling Bifurcations
We unfold the codimension-two simultaneous occurrence of a border-collision
bifurcation and a period-doubling bifurcation for a general piecewise-smooth,
continuous map. We find that, with sufficient non-degeneracy conditions, a
locus of period-doubling bifurcations emanates non-tangentially from a locus of
border-collision bifurcations. The corresponding period-doubled solution
undergoes a border-collision bifurcation along a curve emanating from the
codimension-two point and tangent to the period-doubling locus here. In the
case that the map is one-dimensional local dynamics are completely classified;
in particular, we give conditions that ensure chaos.Comment: 22 pages; 5 figure
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