Discounting with fat-tailed economic growth

When the growth of aggregate consumption exhibits no serial correlation, the socially efficient discount rate is independent of the time horizon, because the wealth effect and the precautionary effect are proportional to the time horizon. In this paper, we consider alternative growth processes: an AR(1), a Brownian motion with unknown trend or volatility, a two-state regime-switching model, and a model with an uncertain return of capital. All these models exhibit some persistence of shocks on the growth rate of the economy and fat tails, which implies that one should discount more distant costs and benefits at a smaller rate.     

Finding socially best spanning trees

This article combines Social Choice Theory with Discrete Optimization. We assume that individuals have preferences over edges of a graph that need to be aggregated. The goal is to find a socially “best” spanning tree in the graph. As ranking all spanning trees is becoming infeasible even for small numbers of vertices and/or edges of a graph, our interest lies in finding algorithms that determine a socially “best” spanning tree in a simple manner. This problem is closely related to the minimum (or maximum) spanning tree problem in Discrete Optimization. Our main result shows that for the various underlying ranking rules on the set of spanning trees discussed in this article, the sets of “best” spanning trees coincide. Moreover, a greedy algorithm based on a transitive group ranking on the set of edges will always provide such a “best” spanning tree.     

Lesbian, gay, and bisexual homeless youth: an eight-city public health perspective

This article reports on results of a one-day public health survey conducted in six states by homeless youth providers to measure and compare risk factors between lesbian, gay, and bisexual (LGB) homeless youth and non-LGB homeless youth. This article intends to inform the child welfare field on existing gaps in services and areas where more training and technical support is necessary in providing services to homeless LGB youth. The findings point to substantial differences within the homeless youth sample and demonstrate that in addition to the public health risks young people face merely by being homeless, the risks are exacerbated for those who self-identify as lesbian, gay, or bisexual. The article informs child welfare providers and policymakers about the substantial vulnerability of LGB youth beyond that of non-LGB homeless youth and the need to fund programming, training, technical assistance and further research to specifically respond to the complex needs of this population.     

Race, ethnicity, gender, and generational factors associated with the coming-out process among lesbian, and bisexual individuals

Age at coming out among gay/lesbian/bisexual (GLB) persons and sexual debut with same-gendered partners has typically been investigated in samples that do not reflect the racial and ethnic diversity of these communities. Addressing this limitation, data were collected from a diverse sample of men and women attending large-scale GLB community events in New York and Los Angeles in 2003 (N = 2,733). Compared to older cohorts, younger cohorts (18-24 year olds) of both men and women reported significantly earlier ages for sexual debut with same-gendered partners, and earlier ages for coming out to themselves and to others. Also, women began the process at later ages than men, as they reported coming out to themselves and sexual debut with a same-gender partner approximately two years later than men. There were no racial or ethnic differences in age out to self or others; however, persons of color were less likely to be out to their parents. Service providers, sexuality educators, and researchers should attend to the diversity in experience of coming out among GLB populations as they relate to the individuals gender, age, and racial and ethnic backgrounds.     

On tests of radial symmetry for bivariate copulas

The unique copula of a continuous random pair \((X,Y)\) is said to be radially symmetric if and only if it is also the copula of the pair \((-X,-Y)\) . This paper revisits the recently considered issue of testing for radial symmetry. Three rank-based statistics are proposed to this end which are asymptotically equivalent but simpler to compute than those of Bouzebda and Cherfi (J Stat Plan Inference 142:1262–1271, 2012). Their limiting null distribution and its approximation using the multiplier bootstrap are discussed. The finite-sample properties of the resulting tests are assessed via simulations. The asymptotic distribution of one of the test statistics is also computed under an arbitrary alternative, thereby correcting an error in the recent work of Dehgani et al. (Stat Pap 54:271–286, 2013).     

Failure Time of Non Homogeneous Gamma Process

We consider the non homogeneous gamma process as a degradation model. The hitting time of a deterministic or random level is studied here. We provide its distribution (both cdf and pdf) explicitly in the first case and in the second case when the threshold is exponentially or gamma distributed. The general case for a random threshold can be approximated by considering mixtures of Erlang distributions. Aging properties are also discussed in this article.     

Introduction: Risk and Uncertainty in Environmental and Resource Economics

Journal of Risk and Uncertainty -