The Effect of the Housing Boom on Farm Land Values via Tax-Deferred Exchanges

This project examines Section 1031 of the Internal Revenue Code and agriculture land exchanges. Stakeholders in rural communities and agriculture are particularly interested in Section 1031 because the recent growth in transaction values of farmland may have, in part, been stimulated by Section 1031 land exchanges. Further, although many have speculated that such exchanges are widely used, little empirical research exists about the provision. We examine the theory of exchanges and develop a theoretical premium value for exchanges. We also present the first evidence of like-kind exchanges involving farmland using Federal tax data.Like-Kind Exchange, Capital Gains Tax, Agricultural Land, Land Economics/Use, Public Economics, Q15, H24,

Colloidal diffusion and hydrodynamic screening near boundaries

The hydrodynamic interactions between colloidal particles in small ensembles are measured at varying distances from a no-slip surface over a range of inter-particle separations. The diffusion tensor for motion parallel to the wall of each ensemble is calculated by analyzing thousands of particle trajectories generated by blinking holographic optical tweezers and by dynamic simulation. The Stokesian Dynamics simulations predict similar particle dynamics. By separating the dynamics into three classes of modes: self, relative and collective diffusion, we observe qualitatively different behavior depending on the relative magnitudes of the distance of the ensemble from the wall and the inter-particle separation. A simple picture of the pair-hydrodynamic interactions is developed, while many-body-hydrodynamic interactions give rise to more complicated behavior. The results demonstrate that the effect of many-body hydrodynamic interactions in the presence of a wall is much richer than the single particle behavior and that the multiple-particle behavior cannot be simply predicted by a superposition of pair interactions

A cautionary note on the appropriateness of using a linkage resource for an association study

BACKGROUND: Utilizing a linkage resource for association analysis requires consideration both of the marker data used and correlations among relatives in pedigrees. We previously developed a method for association testing in pedigrees. We applied our method to 50 replicates of microsatellite data surrounding five genes involved in high-density lipoprotein (HDL) in the Genetic Analysis Workshop 13 (GAW13) simulated data and examined association with HDL as well as linkage disequilibrium (LD) between markers. RESULTS: Although no association was intentionally simulated, we found significant evidence of weak LD between microsatellite markers (flanking/~5 cM from the genes), in some but not all replicates. This level of LD compared well to that observed in the real GAW13 Framingham data. Only one region had sufficient replicates to assess power, and this was low (12.5–20.8%). More power was attained using all individuals and accounting for relationships, compared with one independent individual/pedigree, although this was not significant due to small sample sizes. Not accounting for relatedness inflated statistical significance (p < 0.0001). CONCLUSION: A correction for dependence is necessary in association studies to avoid an inflation of significance probabilities. Our results further illustrate that use of microsatellite marker data is not an effective approach for association testing

GIFTed Demons: deformable image registration with local structure-preserving regularization using supervoxels for liver applications.

Deformable image registration, a key component of motion correction in medical imaging, needs to be efficient and provides plausible spatial transformations that reliably approximate biological aspects of complex human organ motion. Standard approaches, such as Demons registration, mostly use Gaussian regularization for organ motion, which, though computationally efficient, rule out their application to intrinsically more complex organ motions, such as sliding interfaces. We propose regularization of motion based on supervoxels, which provides an integrated discontinuity preserving prior for motions, such as sliding. More precisely, we replace Gaussian smoothing by fast, structure-preserving, guided filtering to provide efficient, locally adaptive regularization of the estimated displacement field. We illustrate the approach by applying it to estimate sliding motions at lung and liver interfaces on challenging four-dimensional computed tomography (CT) and dynamic contrast-enhanced magnetic resonance imaging datasets. The results show that guided filter-based regularization improves the accuracy of lung and liver motion correction as compared to Gaussian smoothing. Furthermore, our framework achieves state-of-the-art results on a publicly available CT liver dataset

Modelling the reduction of quartz in a quartz–carbon pellet

Traditional refining of silicon generates carbon dioxide emissions that are released into the atmosphere. An alternative process under experimental exploration uses quartz particles coated in a layer of porous carbon as the raw material, instead of lumps of quartz and carbon. The quartz–carbon pellets are processed at a lower temperature than in an industrial furnace, and hence, different chemical reactions are dominant, reducing the greenhouse gas emissions. The quartz core shrinks as it is consumed, and the carbon is converted to silicon carbide, which can subsequently be processed into silicon. We develop a model for chemical and transfer processes within a single quartz–carbon pellet. We derive governing equations for the concentration of silicon monoxide, carbon monoxide, and carbon dioxide, and conservation equations on the moving quartz interface. Furthermore, we then focus on a reduced model in an industrially relevant distinguished limit, and solve numerically the resulting leading-order system. We show examples of reaction-limited behaviour as well as diffusion-limited behaviour. Both regimes are physically admissible due to the large potential range of the parameters. Finally, we sweep through the parameter space, and characterize the dynamics based on the utilization of the carbon and the silicon yield. We find that the diffusion-limited regime is best for carbon utilization and silicon yield, as the silicon monoxide reacts with the carbon before it is transported out of the pellet

Critical connectivity in banking networks

The financial crisis of 2007-2009 demonstrated the need to understand the macrodynamics of interconnected financial systems. A fruitful approach to this problem regards financial infrastructures as weighted directed networks, with banks as nodes and loans as links. Using a simple banking model in which banks are linked through interbank lending, with an exogenous shock applied to a single bank, we find a closedform analytical solution for the degree at which failures begin to propagate in the network. This critical degree is expressed as a function of four financial parameters: banking leverage; interbank exposure; return on the investment opportunity; and interbank lending rate. While the transition to failure propagation is sharpest with regular networks, we observe it numerically for random and scale-free networks as well. We find that, if the expected number of failures is not strongly dependent on the network topology and is well captured by the notion of critical degree, the frequency of catastrophic cascades (with a single shock inducing all or most banks in the network to fail) tends to be much larger on scale-free networks than on classical random networks. We interpret this finding as a manifestation of the “robust-yet-fragile” property of scale-free networks

Price Discovery and the Accuracy of Consolidated Data Feeds in the U.S. Equity Markets

Both the scientific community and the popular press have paid much attention to the speed of the Securities Information Processor, the data feed consolidating all trades and quotes across the US stock market. Rather than the speed of the Securities Information Processor, or SIP, we focus here on its accuracy. Relying on Trade and Quote data, we provide various measures of SIP latency relative to high-speed data feeds between exchanges, known as direct feeds. We use first differences to highlight not only the divergence between the direct feeds and the SIP, but also the fundamental inaccuracy of the SIP. We find that as many as 60 percent or more of trades are reported out of sequence for stocks with high trade volume, therefore skewing simple measures such as returns. While not yet definitive, this analysis supports our preliminary conclusion that the underlying infrastructure of the SIP is currently unable to keep pace with the trading activity in today's stock market.Comment: 18 pages, 20 figures, 2 table

Comparisons of Medical Student Knowledge Regarding Life-Threatening CT Images Before and After Clinical Experience

Introduction. Currently, no national standard exists for educatingmedical students regarding radiography or formal research indicatingthe level of improvement regarding computed tomography(CT) interpretation of medical students during clinical rotations. Methods. Students were evaluated based on their response totwenty-two open-ended questions regarding diagnosis and treatmentof eleven de-identified CT images of life-threatening injuries.The number of incorrect answers was compared withcorrect or partially correct answers between students startingthird-year clinical rotations and those starting their fourth year. Results. Survey results were collected from 65 of 65 (100%) beginningthird-year students and 9 of 60 (15%) beginning fourthyearstudents. Students in their fourth-year had less incorrectanswers compared to third-year students, with five questionsreflecting a statistically significant reduction in incorrect responses.The image with the least incorrect for both groups wasepidural hemorrhage, 33.9% and 18.5% incorrect for third-yearstudents for diagnosis and treatment, respectively, and 11.1%and 0% incorrect for fourth-year students. Outside of this image,the range of incorrect answers for third-year students was75.4% to 100% and 44.4% to 100% for fourth-year students. Conclusion. Baseline CT knowledge of medical students,regardless of clinical experience, indicated a strong deficit,as more students were incorrect than correct for themajority of CT images. KS J Med 2017;10(3):55-58

Variation in practice patterns among specialties in the acute management of atrial fibrillation

Abstract Background Atrial fibrillation (AF) is commonly managed by a variety of specialists. Current guidelines differ in their recommendations leading to uncertainty regarding important clinical decisions. We sought to document practice pattern variation among cardiologists, emergency physicians (EP) and hospitalists at a single academic, tertiary-care center. Methods A survey was created containing seven clinical scenarios of patients presenting with AF. We analyzed respondent choices regarding rate vs rhythm control, thromboembolic treatment and hospitalization strategies. Finally, we contrasted our findings with a comparable Australasian survey to provide an international reference. Results There was a 78% response rate (124 of 158), 37% hospitalists, 31.5% cardiologists, and 31.5% EP. Most respondents chose rate over rhythm control (92.2%; 95% CI, 89.1% - 94.5%) and thromboembolic treatment (67.8%; 95% CI, 63.8% - 71.7%). Compared to both hospitalists and EPs, cardiologists were more likely to choose thromboembolic treatment for new and paroxysmal AF (adjusted OR 2.38; 95% CI, 1.05 - 5.41). They were less likely to favor hospital admission across all types of AF (adjusted OR 0.36; 95% CI, 0.17 - 0.79) but thought cardiology consultation was more important (adjusted OR 1.88, 95% CI, 0.97 - 3.64). Australasian physicians were more aggressive with rhythm control for paroxysmal AF with low CHADS2 score compared to US physicians. Conclusions Significant variation exists among specialties in the management of acute AF, likely reflecting a lack of high quality research to direct the provider. Future studies may help to standardize practice leading to decreased rates of hospitalization and overall cost.http://deepblue.lib.umich.edu/bitstream/2027.42/110777/1/12872_2015_Article_9.pd