Challenges in Modeling the Effects of Trade Agreements on the Agricultural Sector

Major issues and challenges encountered in modeling and analyzing agricultural and trade policy reforms are reviewed. We focus on the modeling approach and pay special attention to the type and scope of the models, the calibration of a realistic baseline scenario, the representation of the reform agreement, the use of extra-model information, the choice of metrics to measure reform impacts, and emerging issues in policy modeling. Existing solutions and unresolved issues are examined. We stress the complementarity of various modeling approaches in assessing policy reforms and the importance of helping users understand the limitations of the chosen approach. Keywords: agricultural policy, economic modeling, trade agreements. JEL classification: Q17, Q18, F13

The Enterprise AID Methodology: Concepts

The Enterprise AID − for assessment, improvement, and design − methodology is a systems science-, operational test and evaluation-, and multicriteria decision analysis-based approach to design and deployment of performance measurement systems (PMSs) tailored to specific enterprises pursuing any or all of enterprise assessment, improvement, or design. Its two phases of design and deployment sprang from designers’ inductively generated and now prototyped response to a gap they recognized between performance measurement capabilities required by contemporary enterprises and those offered by contemporary PMSs. This paper illustrates key concepts underlying AID, while a companion document, The Enterprise AID methodology: Application, draws from a prototyping effort to identify value to be gained by stakeholders from PMSs designed and deployed with methodology application

Cross-correlation searches for persistent gravitational waves with Advanced LIGO and noise studies for current and future ground-based gravitational-wave detectors.

University of Minnesota Ph.D. dissertation. 2018. Major: Physics. Advisor: Vuk Mandic. 1 computer file (PDF); 241 pages.Over the last three years, the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) has detected signals from colliding black holes and a signal from colliding neutron stars. These detections ushered in a new era of gravitational-wave (GW) astrophysics and multimessenger astronomy that allows us to probe new regions of the universe. One of the next frontiers for gravitational-wave astronomy is the detection and characterization of the stochastic GW background (SGWB). A measurement of the SGWB from unresolved compact binary systems could come as Advanced LIGO reaches design sensitivity, and future detectors will be important for digging beyond that astrophysical background towards trying to measure signals from relic gravitational waves produced in the early universe. In this dissertation, I present cross-correlation-based searches for a SGWB and other persistent sources of GWs. I introduce and use a new method for setting limits on the strain amplitude of a potential source of GWs in the directions of Scorpius X-1, the galactic center, and Supernova 1987a in the frequency band from 20-1726 Hz. I also set limits on persistent, broadband point sources of GWs across the whole sky. Finally, I show how we can implement data analysis techniques to improve the Advanced LIGO detector sensitivity to persistent sources of GWs. Improving sensitivity of current detectors and planning for future detectors is vital to the effort to measure and understand the SGWB. This will requires a better understanding of the noise sources that limit sensitivity, especially at lower frequencies. To this end, I outline a method for estimating and modeling correlated magnetic noise between spatially separated GW detectors. I also present results from a 3D seismometer array deployed at the Homestake Mine, aimed at characterizing seismic and Newtonian noise for future GW detectors. I estimate the fundamental Rayleigh-wave eigenfunction, and then use it in a seismic radiometer algorithm to separate different components of the seismic field that contribute differently to the Newtonian noise. Finally, I present estimates of the Newtonian noise as a function of depth in the frequency band from 0.5-5 Hz based on results from the seismic radiometer

First search for a stochastic gravitational-wave background from ultralight bosons

Ultralight bosons with masses in the range 10^(−13)  eV ≤ m_b ≤ 10^(−12)  eV can induce a superradiant instability around spinning black holes (BHs) with masses of order 10−100  M⊙. This instability leads to the formation of a rotating “bosonic cloud” around the BH, which can emit gravitational waves (GWs) in the frequency band probed by ground-based detectors. The superposition of GWs from all such systems can generate a stochastic gravitational-wave background (SGWB). In this work, we develop a Bayesian data analysis framework to study the SGWB from bosonic clouds using data from Advanced LIGO and Advanced Virgo, building on previous work by Brito et al. [Phys. Rev. D 96, 064050 (2017)]. We further improve this model by adding a BH population of binary merger remnants. To assess the performance of our pipeline, we quantify the range of boson masses that can be constrained by Advanced LIGO and Advanced Virgo measurements at design sensitivity. Furthermore, we explore our capability to distinguish an ultralight boson SGWB from a stochastic signal due to distant compact binary coalescences (CBC). Finally, we present results of a search for the SGWB from bosonic clouds using data from Advanced LIGO’s first observing run. We find no evidence of such a signal. Due to degeneracies between the boson mass and unknown astrophysical quantities such as the distribution of isolated BH spins, our analysis cannot robustly exclude the presence of a bosonic field at any mass. Nevertheless, we show that under optimistic assumptions about the BH formation rate and spin distribution, boson masses in the range 2.0×10^(−13)  eV ≤ m_b ≤ 3.8×10^(−13)  eV are excluded at 95% credibility, although with less optimistic spin distributions, no masses can be excluded. The framework established here can be used to learn about the nature of fundamental bosonic fields with future gravitational wave observations

Conservation Reserve and Conservation Compliance Programs: Implications for Resource Adjustment

Conservation Titles of the 1985 Food Security Act lead to agricultural market and resource use adjustments. This study explores how the Conservation Reserve Program (CRP) and the Conservation Compliance (CC) Program influence land use, commodity markets, input and technology use, production costs, and the environment. In the case of the Conservation Reserve Program, CARD/FAPRI commodity models are used to generate a baseline and to evaluate the impacts of increasing the amount of land in the reserve. In the case of the Conservation Compliance Program, the CARD ARIMS model is used to generate a baseline without the program and then to evaluate the impacts of imposing erosion restrictions consistent with the conservation compliance provisions. Lower stocks and higher commodity prices would be consequences of expanding the CRP. Resource adjustment associated with conservation compliance can be protracted and may be costly. Insofar as CRP reduces production and strengthens prices, it also can have the effect of increasing the intensity of input use in the remaining planted area. Conservation compliance clearly influences cropping patterns and choices of technology, as well as rates of soil erosion. While production cost increases of 2-4 percent seem relatively small, this could mean as much as 6-15 percent decline in net farm income