USDA Farm Programs: North Dakota Farmer Participation and Opinions

Agricultural and Food Policy,

Network Inference via the Time-Varying Graphical Lasso

Many important problems can be modeled as a system of interconnected entities, where each entity is recording time-dependent observations or measurements. In order to spot trends, detect anomalies, and interpret the temporal dynamics of such data, it is essential to understand the relationships between the different entities and how these relationships evolve over time. In this paper, we introduce the time-varying graphical lasso (TVGL), a method of inferring time-varying networks from raw time series data. We cast the problem in terms of estimating a sparse time-varying inverse covariance matrix, which reveals a dynamic network of interdependencies between the entities. Since dynamic network inference is a computationally expensive task, we derive a scalable message-passing algorithm based on the Alternating Direction Method of Multipliers (ADMM) to solve this problem in an efficient way. We also discuss several extensions, including a streaming algorithm to update the model and incorporate new observations in real time. Finally, we evaluate our TVGL algorithm on both real and synthetic datasets, obtaining interpretable results and outperforming state-of-the-art baselines in terms of both accuracy and scalability

Statistical properties of Klauder-Perelomov coherent states for the Morse potential

We present in this paper a realistic construction of the coherent states for the Morse potential using the Klauder-Perelomov approach . We discuss the statistical properties of these states, by deducing the Q- and P-distribution functions. The thermal expectations for the quantum canonical ideal gas of the Morse oscillators are also calculated

Sustainable Agriculture and the Structure of North Dakota Agriculture

Environmental Economics and Policy, Industrial Organization, Production Economics,

Selected Characteristics of North Dakota Farm Families Engaged in Sustainable Agricultural Practices

Environmental Economics and Policy, Farm Management, Resource /Energy Economics and Policy,

Predispositions and the Political Behavior of American Economic Elites: Evidence from Technology Entrepreneurs

Economic elites regularly seek to exert political influence. But what policies do they support? Many accounts implicitly assume economic elites are homogeneous and that increases in their political power will increase inequality. We shed new light on heterogeneity in economic elites' political preferences, arguing that economic elites from an industry can share distinctive preferences due in part to sharing distinctive predispositions. Consequently, how increases in economic elites' influence affect inequality depends on which industry's elites are gaining influence and which policy issues are at stake. We demonstrate our argument with four original surveys, including the two largest political surveys of American economic elites to date: one of technology entrepreneurs—whose influence is burgeoning—and another of campaign donors. We show that technology entrepreneurs support liberal redistributive, social, and globalistic policies but conservative regulatory policies—a bundle of preferences rare among other economic elites. These differences appear to arise partly from their distinctive predispositions

Segregation, precipitation, and \alpha-\alpha' phase separation in Fe-Cr alloys: a multi-scale modelling approach

Segregation, precipitation, and phase separation in Fe-Cr systems is investigated. Monte Carlo simulations using semiempirical interatomic potential, first-principles total energy calculations, and experimental spectroscopy are used. In order to obtain a general picture of the relation of the atomic interactions and properties of Fe-Cr alloys in bulk, surface, and interface regions several complementary methods has to be used. Using Exact Muffin-Tin Orbitals method the effective chemical potential as a function of Cr content (0-15 at.% Cr) is calculated for a surface, second atomic layer and bulk. At ~10 at.% Cr in the alloy the reversal of the driving force of a Cr atom to occupy either bulk or surface sites is obtained. The Cr containing surfaces are expected when the Cr content exceeds ~10 at.%. The second atomic layer forms about 0.3 eV barrier for the migration of Cr atoms between bulk and surface atomic layer. To get information on Fe-Cr in larger scales we use semiempirical methods. Using combined Monte Carlo molecular dynamics simulations, based on semiempirical potential, the precipitation of Cr into isolated pockets in bulk Fe-Cr and the upper limit of the solubility of Cr into Fe layers in Fe/Cr layer system is studied. The theoretical predictions are tested using spectroscopic measurements. Hard X-ray photoelectron spectroscopy and Auger electron spectroscopy investigations were carried out to explore Cr segregation and precipitation in Fe/Cr double layer and Fe_0.95Cr_0.05 and Fe_0.85Cr_0.15 alloys. Initial oxidation of Fe-Cr was investigated experimentally at 10^-8 Torr pressure of the spectrometers showing intense Cr_2O_3 signal. Cr segregation and the formation of Cr rich precipitates were traced by analysing the experimental spectral intensities with respect to annealing time, Cr content, and kinetic energy of the exited electron.Comment: 16 pages, 14 figures, 52 reference

Assessment of Abundance, Biomass and Production of the Lower Trophic Levels in the Eastern Basin of Lake Erie, 1994

The Lake Erie Biomonitoring (LEB) program conducted in 1994, focused on the eastern basin of the lake, resampling the same sites as in 1993. Nutrient conditions were similar in the two years. Responses differed between the stratified offshore and unstratified nearshore. At the offshore station, seasonal phytoplankton biomass was 56% higher in 1994 than in 1993 and apparently resulted from a reduction in grazing pressure by Dreissena. Dreissena biomass and their potential clearance rates at the offshore station were much lower in the spring of 1994 than in the spring of 1993 (2.5 vs. 14.9 m3·m·2·d·\u27), respectively. Despite this increase in phytoplankton biomass, chlorophyll (Chi) and phytoplankton photosynthesis (PP) were not significantly higher in 1994. Dinoflagellates, which have lower Chl:C and lower photosynthesis:Chl ratios than other groups of phytoplankton, accounted for much of the increase in biomass. Rotifer biomass decreased by 50% and zooplankton biomass by 40% between the two years. Calanoids were responsible for much of the decrease in zooplankton biomass. Composition also shifted towards larger bodied cladocerans, such as Daphnia and Bythotrephes, and away from Bosmina. This shift coincided with changes in predation pressure. Age-one smelt abundance was extremely high in 1993 and low in 1994, while the reverse was true of the YOY smelt. Age-one smelt consume mainly cladocerans and the YOY, copepods (REF). At the nearshore stations, seasonal PP and Chi were well below that expected given the total phosphorus (TP) concentration, indicating that Dreissena had an important impact on phytoplankton photosynthesis in this region. Low transparency due to suspended sediments also contributed to the low PP at station El. Zooplankton biomass was lower in 1994 than in 1993, and species composition and size shifted. Daphnia increased and calanoids and Bosmina decreased in the nearshore as in the offshore, presumably in response to changes in the smelt population. However, Bythotrephes decreased and rotifer biomass increased unlike in the offshore