21,397 research outputs found
MathSBML: a package for manipulating SBML-based biological models
Summary: MathSBML is a Mathematica package designed
for manipulating Systems Biology Markup Language (SBML)
models. It converts SBML models into Mathematica data structures and provides a platform for manipulating and evaluating these models. Once a model is read by MathSBML, it is fully compatible with standard Mathematica functions such as NDSolve (a differential-algebraic equations solver). Math-SBML also provides an application programming interface for viewing, manipulating, running numerical simulations; exporting SBML models; and converting SBML models in to other formats, such as XPP, HTML and FORTRAN. By accessing the full breadth of Mathematica functionality, MathSBML is fully extensible to SBML models of any size or complexity.
Availability: Open Source (LGPL) at http://www.sbml.org and http://www.sf.net/projects/sbml.
Supplementary information: Extensive online documentation is available at http://www.sbml.org/mathsbml.html. Additional examples are provided at http://www.sbml.org/software/mathsbml/bioinformatics-application-not
Oceanographic Profiling Observations from the MOCE-3 Cruise: 27 October to 15 November 1994
This report contains results from the third cruise of the Marine Optical Characterization Experiment (Fig. 1). A variety of spectroradiometric observations of the upper water column and atmosphere were made by investigators from the University of Miami, NOAA, CHORS and MLML. Data presented here were obtained by oceanographic CTD profiler: salinity, temperatllre, dissolved oxygen, beam attenuation and chlorophyll-a fluorescence; and by water samplers: total suspended matter and suspended organic carbon and nitrogen, salinity, and dissolved oxygen
Calibration of Distributionally Robust Empirical Optimization Models
We study the out-of-sample properties of robust empirical optimization
problems with smooth -divergence penalties and smooth concave objective
functions, and develop a theory for data-driven calibration of the non-negative
"robustness parameter" that controls the size of the deviations from
the nominal model. Building on the intuition that robust optimization reduces
the sensitivity of the expected reward to errors in the model by controlling
the spread of the reward distribution, we show that the first-order benefit of
``little bit of robustness" (i.e., small, positive) is a significant
reduction in the variance of the out-of-sample reward while the corresponding
impact on the mean is almost an order of magnitude smaller. One implication is
that substantial variance (sensitivity) reduction is possible at little cost if
the robustness parameter is properly calibrated. To this end, we introduce the
notion of a robust mean-variance frontier to select the robustness parameter
and show that it can be approximated using resampling methods like the
bootstrap. Our examples show that robust solutions resulting from "open loop"
calibration methods (e.g., selecting a confidence level regardless of
the data and objective function) can be very conservative out-of-sample, while
those corresponding to the robustness parameter that optimizes an estimate of
the out-of-sample expected reward (e.g., via the bootstrap) with no regard for
the variance are often insufficiently robust.Comment: 51 page
Income and happiness: Evidence, explanations and economic implications
There is now a great deal of micro-econometric evidence, both cross-section and panel, showing that income is positively correlated with well-being. Yet the famous Easterlin paradox shows essentially no change in average happiness at the country level, despite spectacular rises in per capita GDP. We argue that survey well-being questions are indeed good proxy measures of utility, and resolve the Easterlin paradox by appealing to income comparisons: these can be to others (social comparisons) or to oneself in the past (habituation). We review a substantial amount of econometric, experimental and neurological literature consistent with comparisons, and then spell out the implications for a wide range of economic issues.income ; happiness ; social comparisons ; habituation ; economic policy
The Emergence of Captive Finance Companies and Risk Segmentation of the Consumer Loan Market:Theory and Evidence
A parental seller with market power to some degree in its product market can earn rents. In this context, there is a gain to granting credit for the purchase of the product and thus the establishment of captive finance company for expanding the sales by offering loans to consumers who need financing for purchase of durable good. This paper examines the optimal behavior of such a durable good seller and its captive finance company when the consumer loan market is segmented into captive and independent lending institutions under symmetric and imperfect information on borrower’s creditworthiness. The model presents that one critical difference for captive finance company will be its credit standard. Specifically, the model indicates that captive finance company will follow a more lenient credit standard, leading to the prediction that the likelihood of repayment of a captive loan is lower than that of a bank loan, other things equal. This prediction is tested using unique data sets drawn from a major credit bureau in the U.S. The analysis of credit bureau data shows that a captive automobile loan is less likely to be repaid than a bank automobile loan, which supports the theoretical prediction.Monopolistic Competition, Consumer Loan Market, Captive Finance Company, Differential Loan Performances
Shipboard Techniques for Oceanographic Observations
This report gives the details of water sampling methods and chemical analyses used during MLML participation in the EOS MODIS investigations. It is intended to be used as a reference manual for those engaged in shipboard work. (PDF contains 50 pages
Curves of every genus with many points, II: Asymptotically good families
We resolve a 1983 question of Serre by constructing curves with many points
of every genus over every finite field. More precisely, we show that for every
prime power q there is a positive constant c_q with the following property: for
every non-negative integer g, there is a genus-g curve over F_q with at least
c_q * g rational points over F_q. Moreover, we show that there exists a
positive constant d such that for every q we can choose c_q = d * (log q). We
show also that there is a constant c > 0 such that for every q and every n > 0,
and for every sufficiently large g, there is a genus-g curve over F_q that has
at least c*g/n rational points and whose Jacobian contains a subgroup of
rational points isomorphic to (Z/nZ)^r for some r > c*g/n.Comment: LaTeX, 18 page
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