Supporting the American Dream of Homeownership: An Assessment of Neighborhood Reinvestment's Home Ownership Pilot Program

Based on recommendations from a group of NeighborWorks organization (NWO) directors, Neighborhood Reinvestment initiated the Campaign for Home Ownership in 1993. That campaign provided NWOs with both funding and technical assistance to expand homeownership opportunities in the communities they serve. Based on the experiences of organizations involved with that campaign, Neighborhood Reinvestment staff distilled a model homeownership assistance strategy they call Full-Cycle Lending. This model includes six components: partnership building, pre-purchase home-buyer education, flexible loan products, property services, post-purchase counseling and neighborhood impact. Based on the success of this first five-year Campaign, Neighborhood Reinvestment supported a second five-year campaign called the Campaign for Home Ownership 2002.In 1998 Congress authorized $25 million for a NeighborWorks Home Ownership Pilot program designed to leverage additional local support and test new strategies for assisting first-time home buyers. In less than four months, the Neighborhood Reinvestment Home Ownership Campaign staff developed and implemented specific program guidelines for the distribution of funds to local NWOs. These guidelines allowed NWOs great flexibility in the use of Pilot funds including using the funds for upgrading computers, hiring staff, developing marketing plans and programs, capitalizing loan funds, providing down payment assistance as well as other uses.Campaign staff developed guidelines for three funding categories, A, B, and C, designed to respond to the different needs of NWOs. Category A grants (up to$500,000) were to assist NWOs that were already assisting 30 or more home buyers a year increase the number of home buyers assisted. Category B grants (up to $500,000) were to assist NWOs that were already assisting a large number of new home buyers enhance the positive impacts of home ownership on their target areas by undertaking other neighborhood improvement activities as well as increasing the number of home buyers assisted. Category C grants (up to$50,000) were to assist NWOs that were assisting a relatively low number of new home buyers build their capacities to do so. A total of 35 Category A grants were made, nine Category B grants and 40 Category C grants.To assist Campaign and Pilot sites in achieving their goals, Neighborhood Reinvestment provides several types of technical assistance. The semi-annual Neighborhood Reinvestment Training Institute offers a variety of courses on developing homeownership promotion programs and home-owner education methods. Neighborhood Reinvestment has also developed an extensive array of marketing materials that can be used by Campaign and Pilot organizations. Finally, Neighborhood Reinvestment Campaign and field staff assist participating organizations with special challenges as they arise.This report is the second of three reports evaluating the outcomes, implementation process and impacts of the Pilot. The outcome evaluation was designed to document the results of the Pilot including the number of persons trained and/or counseled, the number of new home owners assisted, and the value of housing units purchased, built or rehabilitated with the assistance of the Pilot organizations. This evaluation is based on information provided to Neighborhood Reinvestment by participating NWOs. The process evaluation was designed to document and evaluate the efforts of Neighborhood Reinvestment and participating NWOs in planning and implementing the Pilot programs. This part of the evaluation is based on interviews conducted in two rounds of site visits to eight Category A and B Pilot programs -- once in the fall of 1999 and once in the spring and summer of 2001. Finally, the impact evaluation was designed to assess the influence of the Pilot on the participating NWOs and their clients. The evaluation is based on interviews with NWO staff and focus groups of new home owners assisted in the eight sites visited

Symmetry and optical selection rules in graphene quantum dots

Graphene quantum dots (GQD's) have optical properties which are very different from those of an extended graphene sheet. In this Article we explore how the size, shape and edge--structure of a GQD affect its optical conductivity. Using representation theory, we derive optical selection rules for regular-shaped dots, starting from the symmetry properties of the current operator. We find that, where the x- and y-components of the current operator transform with the same irreducible representation (irrep) of the point group - for example in triangular or hexagonal GQD's - the optical conductivity is independent of the polarisation of the light. On the other hand, where these components transform with different irreps - for example in rectangular GQD's - the optical conductivity depends on the polarisation of light. We find that GQD's with non-commuting point-group operations - for example dots of rectangular shape - can be distinguished from GQD's with commuting point-group operations - for example dots of triangular or hexagonal shape - by using polarized light. We carry out explicit calculations of the optical conductivity of GQD's described by a simple tight--binding model and, for dots of intermediate size, \textcolor{blue}{($10 \lesssim L \lesssim 50\ \text{nm}$)} find an absorption peak in the low--frequency range of the spectrum which allows us to distinguish between dots with zigzag and armchair edges. We also clarify the one-dimensional nature of states at the van Hove singularity in graphene, providing a possible explanation for very high exciton-binding energies. Finally we discuss the role of atomic vacancies and shape asymmetry.Comment: 24 pages, 15 figure

Simple observations concerning black holes and probability

It is argued that black holes and the limit distributions of probability theory share several properties when their entropy and information content are compared. In particular the no-hair theorem, the entropy maximization and holographic bound, and the quantization of entropy of black holes have their respective analogues for stable limit distributions. This observation suggests that the central limit theorem can play a fundamental role in black hole statistical mechanics and in a possibly emergent nature of gravity.Comment: 6 pages Latex, final version. Essay awarded "Honorable Mention" in the Gravity Research Foundation 2009 Essay Competitio

Information capacity of genetic regulatory elements

Changes in a cell's external or internal conditions are usually reflected in the concentrations of the relevant transcription factors. These proteins in turn modulate the expression levels of the genes under their control and sometimes need to perform non-trivial computations that integrate several inputs and affect multiple genes. At the same time, the activities of the regulated genes would fluctuate even if the inputs were held fixed, as a consequence of the intrinsic noise in the system, and such noise must fundamentally limit the reliability of any genetic computation. Here we use information theory to formalize the notion of information transmission in simple genetic regulatory elements in the presence of physically realistic noise sources. The dependence of this "channel capacity" on noise parameters, cooperativity and cost of making signaling molecules is explored systematically. We find that, at least in principle, capacities higher than one bit should be achievable and that consequently genetic regulation is not limited the use of binary, or "on-off", components.Comment: 17 pages, 9 figure

The classical capacity of quantum thermal noise channels to within 1.45 bits

We find a tight upper bound for the classical capacity of quantum thermal noise channels that is within $1/\ln 2$ bits of Holevo's lower bound. This lower bound is achievable using unentangled, classical signal states, namely displaced coherent states. Thus, we find that while quantum tricks might offer benefits, when it comes to classical communication they can only help a bit.Comment: Two pages plus a bi

Bias Analysis in Entropy Estimation

We consider the problem of finite sample corrections for entropy estimation. New estimates of the Shannon entropy are proposed and their systematic error (the bias) is computed analytically. We find that our results cover correction formulas of current entropy estimates recently discussed in literature. The trade-off between bias reduction and the increase of the corresponding statistical error is analyzed.Comment: 5 pages, 3 figure

Highly optimized tolerance and power laws in dense and sparse resource regimes

Power law cumulative frequency $(P)$ vs. event size $(l)$ distributions $P(\geq l)\sim l^{-\alpha}$ are frequently cited as evidence for complexity and serve as a starting point for linking theoretical models and mechanisms with observed data. Systems exhibiting this behavior present fundamental mathematical challenges in probability and statistics. The broad span of length and time scales associated with heavy tailed processes often require special sensitivity to distinctions between discrete and continuous phenomena. A discrete Highly Optimized Tolerance (HOT) model, referred to as the Probability, Loss, Resource (PLR) model, gives the exponent $\alpha=1/d$ as a function of the dimension $d$ of the underlying substrate in the sparse resource regime. This agrees well with data for wildfires, web file sizes, and electric power outages. However, another HOT model, based on a continuous (dense) distribution of resources, predicts $\alpha= 1+ 1/d$. In this paper we describe and analyze a third model, the cuts model, which exhibits both behaviors but in different regimes. We use the cuts model to show all three models agree in the dense resource limit. In the sparse resource regime, the continuum model breaks down, but in this case, the cuts and PLR models are described by the same exponent.Comment: 19 pages, 13 figure

Security of coherent state quantum cryptography in the presence of Gaussian noise

We investigate the security against collective attacks of a continuous variable quantum key distribution scheme in the asymptotic key limit for a realistic setting. The quantum channel connecting the two honest parties is assumed to be lossy and imposes Gaussian noise on the observed quadrature distributions. Secret key rates are given for direct and reverse reconciliation schemes including postselection in the collective attack scenario. The effect of a non-ideal error correction and two-way communication in the classical post-processing step is also taken into account.Comment: 12 pages, 5 figures updated version including two-way communication; changed the definition of the excess noise to match the definition given earlier (Phys. Rev. Lett. 92, 117901); submitted to PRA; presented at the 8th International Conference on Quantum Communication, Measurement and Computing, Tsukub