The Use of Social Capital in Borrower Decision-Making

By looking beyond the financial characteristics of borrowers, this research brings to light the social factors that influence a borrower's choice of a lender and mortgage product. Previous research has indicated that distinct channels exist that funnel borrowers into lower or higher cost loan products (Apgar, Bendimerad, and Essene 2007). But little is known as to how borrowers seek out or are directed to such channels. A particular concern that this paper hopes to address is why black borrowers disproportionately have higher priced products.Some research indicates that even when credit worthiness is controlled for, blacks are overrepresented in the subprime sector and in higher-cost products (Bocian, Ernst, and Li 2006). Through in-depth interviews with 32 borrowers, this research (1) highlights how borrowers seek mortgage credit and evaluate their mortgage options, and (2) demonstrates how borrowers make use of their social networks (friends and family) when making their decisions.The preliminary findings indicate that borrowers' preferences and subsequent demands for mortgage products were shaped by the informal and formal advice they received. Those borrowers who consulted the most diverse sources of information had loans with lower interest rates. Those borrowers who received advice only from family and friends did not fare as well as those who received help from credit counselors. Thus, arguably, their loan outcomes varied not just based on if they consulted others, but especially whom they consulted. When given the right advice, potential homebuyers make better decisions in choosing both a lender and a loan

Fearless: Cassi Franz

Cassi Franz ’13 has been fearlessly leading this year’s Day of Service. The Day of Service occurs annually and honors Emily Silverstein, a student who passed away in 2009. Emily contributed to Gettysburg’s campus community and beyond through her compassion as well as her passion for social justice. Noor Oweis ’11 started the day of service in 2010 to honor her friend, and now Cassi carries on that tradition. [excerpt

Aging dynamics and the topology of inhomogenous networks

We study phase ordering on networks and we establish a relation between the exponent $a_\chi$ of the aging part of the integrated autoresponse function $\chi_{ag}$ and the topology of the underlying structures. We show that $a_\chi >0$ in full generality on networks which are above the lower critical dimension $d_L$, i.e. where the corresponding statistical model has a phase transition at finite temperature. For discrete symmetry models on finite ramified structures with $T_c = 0$, which are at the lower critical dimension $d_L$, we show that $a_\chi$ is expected to vanish. We provide numerical results for the physically interesting case of the $2-d$ percolation cluster at or above the percolation threshold, i.e. at or above $d_L$, and for other networks, showing that the value of $a_\chi$ changes according to our hypothesis. For $O({\cal N})$ models we find that the same picture holds in the large-${\cal N}$ limit and that $a_\chi$ only depends on the spectral dimension of the network.Comment: LateX file, 4 eps figure

Conductivity fluctuations in polymer's networks

Polymer's network is treated as an anisotropic fractal with fractional dimensionality D = 1 + \epsilon close to one. Percolation model on such a fractal is studied. Using the real space renormalization group approach of Migdal and Kadanoff we find threshold value and all the critical exponents to be strongly nonanalytic functions of \epsilon, e.g. the critical exponent of the conductivity was obtained to be \epsilon^{-2}\exp(-1-1/\epsilon). The main part of the finite size conductivities distribution function at the threshold was found to be universal if expressed in terms of the fluctuating variable, which is proportional to the large power of the conductivity, but with dimensionally-dependent low-conductivity cut-off. Its reduced central momenta are of the order of \exp(-1/\epsilon) up to the very high order.Comment: 7 pages, one eps figure, uses epsf style, to be published in Proc. of LEES-97 (Physica B

Bose-Einstein Condensation on inhomogeneous complex networks

The thermodynamic properties of non interacting bosons on a complex network can be strongly affected by topological inhomogeneities. The latter give rise to anomalies in the density of states that can induce Bose-Einstein condensation in low dimensional systems also in absence of external confining potentials. The anomalies consist in energy regions composed of an infinite number of states with vanishing weight in the thermodynamic limit. We present a rigorous result providing the general conditions for the occurrence of Bose-Einstein condensation on complex networks in presence of anomalous spectral regions in the density of states. We present results on spectral properties for a wide class of graphs where the theorem applies. We study in detail an explicit geometrical realization, the comb lattice, which embodies all the relevant features of this effect and which can be experimentally implemented as an array of Josephson Junctions.Comment: 11 pages, 9 figure

Random walks on graphs: ideas, techniques and results

Random walks on graphs are widely used in all sciences to describe a great variety of phenomena where dynamical random processes are affected by topology. In recent years, relevant mathematical results have been obtained in this field, and new ideas have been introduced, which can be fruitfully extended to different areas and disciplines. Here we aim at giving a brief but comprehensive perspective of these progresses, with a particular emphasis on physical aspects.Comment: LateX file, 34 pages, 13 jpeg figures, Topical Revie

Light Transmission Properties and Shannon Index in One-Dimensional Photonic Media With Disorder Introduced by Permuting the Refractive Index Layers

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Diffusive Thermal Dynamics for the Ising Ferromagnet

We introduce a thermal dynamics for the Ising ferromagnet where the energy variations occurring within the system exhibit a diffusive character typical of thermalizing agents such as e.g. localized excitations. Time evolution is provided by a walker hopping across the sites of the underlying lattice according to local probabilities depending on the usual Boltzmann weight at a given temperature. Despite the canonical hopping probabilities the walker drives the system to a stationary state which is not reducible to the canonical equilibrium state in a trivial way. The system still exhibits a magnetic phase transition occurring at a finite value of the temperature larger than the canonical one. The dependence of the model on the density of walkers realizing the dynamics is also discussed. Interestingly the differences between the stationary state and the Boltzmann equilibrium state decrease with increasing number of walkers.Comment: 9 pages, 14 figures. Accepted for publication on PR

Viral Transfer and Inactivation through Zooplankton Trophic Interactions

Waterborne viruses are responsible for numerous diseases and are abundant in aquatic systems. Understanding the fate of viruses in natural systems has important implications for human health. This research quantifies the uptake of the bacteriophage T4 and the enteric virus echovirus 11 when exposed to the filter feeders Tetrahymena pyriformis and Daphnia magna, and also examines the potential of viral transfer due to trophic interactions. Experiments co-incubating each species with the viruses over 72-96 h showed up to a 4 log virus removal for T. pyriformis, while direct viral uptake by D. magna was not observed. However, viral uptake by D. magna occurred indirectly by viral transfer from prey to predator, through D. magna feeding on virus-loaded T. pyriformis. This prey-predator interaction resulted in a 1 log additional virus removal compared to removal by T. pyriformis alone. Incomplete viral inactivation by D. magna was observed through recovery of infective viruses from the daphnid tissue. This research furthers our understanding of the impacts of zooplankton filter feeding on viral inactivation and shows the potential for viral transfer through the food chain. The viral-zooplankton interactions observed in these studies indicate that zooplankton may improve water quality through viral uptake or may serve as vectors for infection by accumulating viruses

Classical XY Model in 1.99 Dimensions

We consider the classical XY model (O(2) nonlinear sigma-model) on a class of lattices with the (fractal) dimensions 1<D<2. The Berezinskii's harmonic approximation suggests that the model undergoes a phase transition in which the low temperature phase is characterized by stretched exponential decay of correlations. We prove an exponentially decaying upper bound for the two-point correlation functions at non-zero temperatures, thus excluding the possibility of such a phase transition.Comment: LaTeX 8 pages, no figure