Analysis of Swarm Behavior in Two Dimensions

We investigate the steady state solutions that can exist for a two dimensional swarm of biological organisms, which have pairwise social interaction forces. The three steady states we investigate using a continuum model are a ribbon migrating swarm, a circular migrating swarm, and a milling swarm. We solve these numerically by reformulating the integral equation that arises from the continuum model as an energy minimization problem. For the ribbon migrating solution, we are able to determine an analytic solution from Carleman\u27s equation which arises after an asymptotic expansion of the social interaction potential. Using this technique we are able to show the existence of a square root singularity that emerges at the boundary of the compactly supported swarm. The analytic solution agrees with the numerical solution for certain parameter values in the social interaction potential. We then demonstrate the existence of solutions for a migrating and milling circular swarm which contain a square root singularity. The milling swarm looks similar to the infinite ribbon, so we are able to use an asymptotic expansion of the potential to obtain an analytic solution in this case as well. The singularities in the density of the swarm suggest that the Morse potential should not be used for modeling biological swarming

Are Mortgage Rates Bubbling Up Trouble for Canadas Metropolitan Housing Sector?

This paper determines how mortgage rate and income shocks affect new and resale housing prices, housing starts, and housing sales in Canadas metropolitan areas. We assess the variance decompositions and impulse response results to mortgage rate and income shocks. An additional set of VARs is estimated to document whether the stock price, as an alternative source of investment, reduces the importance of the mortgage rate. Our results show that the importance of the mortgage rate and income varies significantly by metropolitan area and to a lesser degree, by the component of the housing market examined. More precisely, we find that: 1) two of BCs major metropolitan areas housing markets, Vancouver and Victoria, are vulnerable to interest rate bubble;. 2) Mortgage rates, and by extension the Bank of Canada monetary policy, seems to have little direct impact on Albertas major metropolitan housing markets, Calgary and Edmonton, while income can be expected to have a drastic effect; and 3) The housing markets of Ontarios major metropolitan area and Canadas Capital Region are prone to mortgage rate bubbles, but the impact is dampened due to their connectedness to national financial markets. What these results mean in terms of policy-making decision is that close attention needs to be paid to housing markets in Canada that are vulnerable to spikes in mortgage rates as we are coming out of the recession provoked by the housing market meltdown in the United States. Although it is true that Banking regulations in Canada have helped weather the storm, with the massive fiscal stimulus implemented in both Canada and the United States, eventually strong aggregate demand may build up pressure on prices to rise and interest rate will have to increase in order to maintain price stability, thereby causing troubles for mortgagees.Housing Markets, Metropolitan Areas in Canada, Monetary Policy, Stock Prices, Provincial Income, Variance Decomposition

Elastic Cheerios effect: self-assembly of cylinders on a soft solid

A rigid cylinder placed on a soft gel deforms its surface. When multiple cylinders are placed on the surface, they interact with each other via the topography of the deformed gel which serves as an energy landscape; as they move, the landscape changes which in turn changes their interaction. We use a combination of experiments, simple scaling estimates and numerical simulations to study the self-assembly of cylinders in this elastic analog of the Cheerios effect for capillary interactions on a fluid interface. Our results show that the effective two body interaction can be well described by an exponential attraction potential as a result of which the dynamics also show an exponential behavior with respect to the separation distance. When many cylinders are placed on the gel, the cylinders cluster together if they are not too far apart; otherwise their motion gets elastically arrested

Iterative seismic data interpolation using plane-wave shaping

textGeophysical applications often require finding an appropriate solution to an ill-posed inverse problem. An example application is interpolating irregular or sparse data to a regular grid. This data regularization problem must be addressed appropriately before many data processing techniques can begin. In this thesis, I investigate plane-wave shaping in two and three dimensions as a data regularization algorithm, which can be used for the interpolation of seismic data and images. I use plane-wave shaping to interpolate several synthetic and field datasets and test its accuracy in image reconstruction. Because plane-wave shaping adheres to the direction of the local slopes of an image, the image-guided interpolation scheme attempts to preserve information of geologic structures. I apply several alternative interpolation schemes - formulated as an inverse problem with a convolutional operator to constrain the model space - namely: plane-wave destruction, plane-wave construction, and prediction-error filters. Investigating their iterative convergence rates, I find that plane-wave shaping converges to a solution in fewer iterations than the alternative techniques. I find that the only required parameter for this method, the smoothing radius, is best chosen to be approximately the same size as the holes for missing-data problems. The optional parameter for edge padding is best selected as approximately half of the smoothing radius. Applications of this research project include potential applications in well-log interpolation, seismic tomography, and 5-D seismic data interpolation.Geological Science

Differential Response to Foliar Pathogens in Wheat as a Consequence of Cytoplasmic Substitution

Wheat alloplasmic lines are plants where the cytoplasmic genome of one wheat species was substituted by those of a wild relative, while maintaining the original nucleus. Our project studied differential responses of various alien cytoplasm in a specific nuclear background to various pathogens to identify NC interaction effects on biotic stress tolerance. This study analyzed fifty selected alloplasmic lines that were tested for disease response to Pyrenophora tritici-repentis isolates Br15 and Pti2. Results indicate that Ae. bicornis cytoplasm with nuclei donor of Chris and Selkirk provides increased resistance to tan spot isolate Br15. Puccinia triticina was used in determining differential responses between alloplasmic and euplasmic lines. A bulk set of four leaf rust isolates indicated Aegilops heldreichii cytoplasm with Chris nucleus provides resistance to the susceptible euplasmic line Chris and showed increased resistance to both tan spot isolates. These data indicates that cytoplasmic variability can improve resistance to plant diseases

Analysis of the Radius of Convergence of the Perturbation Expansion for the Ground State Energy of Two-Electron Atoms

This thesis solves a controversial physics problem that has existed in the literature for nearly a century { nding the radius of convergence of the perturbation expansion for the ground state energy of the two-electron atom. This problem is important to study because it makes progress towards nding the possible structures that can exist in the quantum mechanical three-body problem. This perturbation expansion is a convergent series and in physics these are rare to work with. We usually refer to this perturbation expansion as the \1=Z expansion . There is still much to learn about nding e ective methods of determining the radii of convergence for convergent series. The rst 1000 coe cients of the 1=Z expansion are calculated with very high precision and are compared to previous values in the literature. These coe cients are determined by using a new type of basis set that is introduced in this work, the pyramidal basis set, which is very useful in describing high-order wave functions generated by perturbation theory. Using the series of ratios of the resulting coe cients along with a series acceleration technique, the radius of convergence of the 1=Z expansion is found to be = 1:0975(2)

Virus Testing Across Multiple Platforms

Systems Engineering, as a value added re-seller, has noticed a number of organizations questioning the value of anti-virus / anti-malware applications in addition to native operating system protections. So the Maine Cyber Security Cluster (MCSC) at USM teamed up with Systems Engineering in Portland to find out exactly what would happen if a great deal of viruses and malware made it onto your computer that is protected with anti-virus programs they recommend to clients. We used a variety of different operating systems with an assortment of anti-virus programs. These are all either currently in use by Systems Engineering or are being considered for future distribution. During each test we injected a fixed amount of viruses and malware on each system upon which we found varying effectiveness. The focus of this testing was to provide the end user the most effective anti-virus program pared with their operating system

College Students’ Knowledge of and Openness to Students with Autism Spectrum Disorder

College students with autism spectrum disorder (ASD) face challenges due to limited understanding of this condition. This study investigates college students\u27 awareness of and openness to peers with ASD using an educational intervention. Data were analyzed via a pre–post survey design with two groups. Factorial analysis of variance showed no significant differences between groups. However, a Wilcoxon signed-rank test revealed significant differences in the treatment group’s ranks on the openness scale and knowledge scale between pre- and post-intervention surveys. Findings yielded small (openness) and large effect sizes (knowledge) as expected. Brief educational interventions in required courses can thus potentially enhance students’ knowledge and engender positive future interactions with students with ASD