FRANKLIN COUNTY, IOWA'S PROGRAM IN PUBLIC AFFAIRS

Public Economics,

Loop Calculus in Statistical Physics and Information Science

Considering a discrete and finite statistical model of a general position we introduce an exact expression for the partition function in terms of a finite series. The leading term in the series is the Bethe-Peierls (Belief Propagation)-BP contribution, the rest are expressed as loop-contributions on the factor graph and calculated directly using the BP solution. The series unveils a small parameter that often makes the BP approximation so successful. Applications of the loop calculus in statistical physics and information science are discussed.Comment: 4 pages, submitted to Phys.Rev.Lett. Changes: More general model, Simpler derivatio

Gaussian Belief with dynamic data and in dynamic network

In this paper we analyse Belief Propagation over a Gaussian model in a dynamic environment. Recently, this has been proposed as a method to average local measurement values by a distributed protocol ("Consensus Propagation", Moallemi & Van Roy, 2006), where the average is available for read-out at every single node. In the case that the underlying network is constant but the values to be averaged fluctuate ("dynamic data"), convergence and accuracy are determined by the spectral properties of an associated Ruelle-Perron-Frobenius operator. For Gaussian models on Erdos-Renyi graphs, numerical computation points to a spectral gap remaining in the large-size limit, implying exceptionally good scalability. In a model where the underlying network also fluctuates ("dynamic network"), averaging is more effective than in the dynamic data case. Altogether, this implies very good performance of these methods in very large systems, and opens a new field of statistical physics of large (and dynamic) information systems.Comment: 5 pages, 7 figure

Data assimilation for the Martian atmosphere using MGS Thermal Emission Spectrometer observations

From the introduction: Given the quantity of data expected from current and forthcoming spacecraft missions to Mars, it is now possible to use data assimilation as a means of atmospheric analysis for the first time for a planet other than the Earth. Several groups have described plans to develop assimilation schemes for Mars [Banfield et al., 1995; Houben, 1999; Lewis and Read, 1995; Lewis et al., 1996, 1997; Zhang et al., 2001]. Data assimilation is a technique for the analysis of atmospheric observations which combines currently valid information with prior knowledge from previous observations and dynamical and physical constraints, via the use of a numerical model. Despite the number of new missions, observations of the atmosphere of Mars in the near future are still likely to be sparse when compared to those of the Earth, perhaps comprising one orbiter and a few surface stations at best at any one time. Data assimilation is useful as a means to extract the maximum information from such observations, both by a form of interpolation in space and time using model constraints and by the combination of information from different observations, e.g. temperature profiles and surface pressure measurements which may be irregularly distributed. The procedure can produce a dynamically consistent set of meteorological fields and can be used directly to test and to refine an atmospheric model against observations

Assimilation of TES data from the Mars Global Surveyor scientifc mapping phase

The Thermal Emission Spectrometer (TES)aboard Mars Global Surveyor has produced data which cover almost two Martian years so far (during its scientific mapping phase). Thermal profiles for the atmosphere below 40 km and total dust opacities can be retrieved from TES nadir spectra and assimilated into a Mars general circulation model (MGCM), by using the assimilation techniques described in detail by Lewis et al. (2002). This paper describes some preliminary results from assimilations of temperature data from the period Ls=141°- 270° corresponding to late northern summer until winter solstice on Mars. Work in progress is devoted to assimilate both temperature and total dust opacity data for the full period for which they are already available

Hierarchical Models for Independence Structures of Networks

We introduce a new family of network models, called hierarchical network models, that allow us to represent in an explicit manner the stochastic dependence among the dyads (random ties) of the network. In particular, each member of this family can be associated with a graphical model defining conditional independence clauses among the dyads of the network, called the dependency graph. Every network model with dyadic independence assumption can be generalized to construct members of this new family. Using this new framework, we generalize the Erd\"os-R\'enyi and beta-models to create hierarchical Erd\"os-R\'enyi and beta-models. We describe various methods for parameter estimation as well as simulation studies for models with sparse dependency graphs.Comment: 19 pages, 7 figure

The men behind economically successful women: A focus on Dutch dual-earner couples

Abstract Using data from the Netherlands Kinship Panel Study, this paper compares the partners of economically successful women with those of women who have fared less well on the labor market. Economic success is measured as belonging to the top ten percent income bracket of the female sample. First, socioeconomic and cultural homogamy/asymmetry are investigated. With respect to education, homogamy is the dominant pattern. Income asymmetry, where husbands contribute most to the household income, characterizes the majority of couples, particularly in the older age groups. Gender asymmetry in cultural resources is predominant, with women having more modern gender role attitudes than men. Second, hypotheses derived from social capital theory and companionate theory are tested to examine how socioeconomic and cultural characteristics of male partners are related to women’s economic success. Economically successful women tend to have high-income men, suggesting an accumulation of favorable resources. A larger share of the male partner in carrying out household tasks is positively related to a woman’s success. Men’s supportive behavior rather than their attitudes contribute to their wives’ economic success

Trusting Telework in the Federal Government

Despite an Executive Office mandate to permit federal workers to telework, federal managers still deny employees this benefit. Several factors have been attributed to their aversion, including lack of trust. Findings from a hermeneutic phenomenological study exploring the lived experiences and perceptions of 12 federal government managers who prohibit their employees from teleworking (Brown, 2013) was analyzed to identify themes related to trust. Of the eight themes Brown identified, five focused on lack of trust. This paper discusses those five trust-related themes and recommends success factors for enabling leaders’ trust of telework are discussed

Detection Prospects for Majorana Fermion WIMPless Dark Matter

We consider both velocity-dependent and velocity-independent contributions to spin-dependent (SD) and spin-independent (SI) nuclear scattering (including one-loop corrections) of WIMPless dark matter, in the case where the dark matter candidate is a Majorana fermion. We find that spin-independent scattering arises only from the mixing of exotic squarks, or from velocity-dependent terms. Nevertheless (and contrary to the case of MSSM neutralino WIMPs), we find a class of models which cannot be detected through SI scattering, but can be detected at IceCube/DeepCore through SD scattering. We study the detection prospects for both SI and SD detection strategies for a large range of Majorana fermion WIMPless model parameters.Comment: 14 pages, 3 figures. v2: updated to match published versio