Catalytic Oxidation of Styrene in the Presence of Square Planar Cobalt(iii) Complexes of Polyanionic Chelating Ligands

Styrene has been catalytically oxidised in the presence of iodosoarenes and square planar cobalt(iii) complexes of polyanionic chelating (PAC) ligands; possible intermediates in these oxygen atom transfer reactions include cobalt(v)-oxo complexes

Learning Dynamic Boltzmann Distributions as Reduced Models of Spatial Chemical Kinetics

Finding reduced models of spatially-distributed chemical reaction networks requires an estimation of which effective dynamics are relevant. We propose a machine learning approach to this coarse graining problem, where a maximum entropy approximation is constructed that evolves slowly in time. The dynamical model governing the approximation is expressed as a functional, allowing a general treatment of spatial interactions. In contrast to typical machine learning approaches which estimate the interaction parameters of a graphical model, we derive Boltzmann-machine like learning algorithms to estimate directly the functionals dictating the time evolution of these parameters. By incorporating analytic solutions from simple reaction motifs, an efficient simulation method is demonstrated for systems ranging from toy problems to basic biologically relevant networks. The broadly applicable nature of our approach to learning spatial dynamics suggests promising applications to multiscale methods for spatial networks, as well as to further problems in machine learning

Examining Students’ Perceptions of Globalization and Study Abroad Programs at HBCUs

The objective in this paper is to explore students’ perceptions of globalization and study abroad programs at Historically Black Colleges and Universities (HBCUs). Recent statistics reveal that in spite of the current growth in the number of US students receiving academic credit for their overseas academic experience, less than one percent of undergraduate minority students participate in a study abroad program during their degree program. The analysis is based on survey questionnaires administered to 263 undergraduate minority students at Alabama A&M University. The questionnaire contained questions related to respondents’ demographic characteristics and likert-scale questions pertaining to students’ perceptions of globalization and studying abroad programs. The data are analyzed using factor analysis and binary logistic regression. The results of the regression model suggest that while a number of variables such as major and classification are found to have statistically significant relationships towards globalization, demographic variables and information source variables are not good indicators of student perceptions of globalization. One interesting findings is that with a global mindset, business students seem to be more favorably inclined toward globalization than non-business students.Globalization, Study Abroad Programs, Logistic Regression, Factor Analysis, Survey Data, Agribusiness, Agricultural and Food Policy, International Development, Research Methods/ Statistical Methods,

Effect of Foreclosure Status on Residential Selling Price: Comment

In this comment we examine the conclusion by Forgey, Rutherford, and VanBuskirk (1994) "that the foreclosed properties sold at a 23% discount," using a sample of nearly 2,000 residential property sales from the Las Vegas, Nevada area. We found that when not controlling for location with a set of dummy variables for ZIP codes, HUD foreclosed properties sold for between 12.18% and 13.96% below a random sample of properties not within one block of foreclosed properties. When controlling for location, using a set of thirty-one dummy variables for ZIP codes, the foreclosure discount fell to between 8.45% and 9.72%. When controlling for the common characteristics between foreclosed properties and their neighbors, we found foreclosure discounts are very small (between 0.17% and 2.48%) and no longer statistically significant. We conclude that foreclosure does not provide an opportunity for arbitrage profits, and this study does reinforce the findings of other studies that conclude real estate markets operate efficiently.

Structure-Aware Shape Synthesis

We propose a new procedure to guide training of a data-driven shape generative model using a structure-aware loss function. Complex 3D shapes often can be summarized using a coarsely defined structure which is consistent and robust across variety of observations. However, existing synthesis techniques do not account for structure during training, and thus often generate implausible and structurally unrealistic shapes. During training, we enforce structural constraints in order to enforce consistency and structure across the entire manifold. We propose a novel methodology for training 3D generative models that incorporates structural information into an end-to-end training pipeline.Comment: Accepted to 3DV 201

Geometric principles of second messenger dynamics in dendritic spines.

Dendritic spines are small, bulbous protrusions along dendrites in neurons and play a critical role in synaptic transmission. Dendritic spines come in a variety of shapes that depend on their developmental state. Additionally, roughly 14-19% of mature spines have a specialized endoplasmic reticulum called the spine apparatus. How does the shape of a postsynaptic spine and its internal organization affect the spatio-temporal dynamics of short timescale signaling? Answers to this question are central to our understanding the initiation of synaptic transmission, learning, and memory formation. In this work, we investigated the effect of spine and spine apparatus size and shape on the spatio-temporal dynamics of second messengers using mathematical modeling using reaction-diffusion equations in idealized geometries (ellipsoids, spheres, and mushroom-shaped). Our analyses and simulations showed that in the short timescale, spine size and shape coupled with the spine apparatus geometries govern the spatiotemporal dynamics of second messengers. We show that the curvature of the geometries gives rise to pseudo-harmonic functions, which predict the locations of maximum and minimum concentrations along the spine head. Furthermore, we showed that the lifetime of the concentration gradient can be fine-tuned by localization of fluxes on the spine head and varying the relative curvatures and distances between the spine apparatus and the spine head. Thus, we have identified several key geometric determinants of how the spine head and spine apparatus may regulate the short timescale chemical dynamics of small molecules that control synaptic plasticity