Estimating percentiles of uncertain computer code outputs

Summary.  A deterministic computer model is to be used in a situation where there is uncertainty about the values of some or all of the input parameters. This uncertainty induces uncertainty in the output of the model. We consider the problem of estimating a specific percentile of the distribution of this uncertain output. We also suppose that the computer code is computationally expensive, so we can run the model only at a small number of distinct inputs. This means that we must consider our uncertainty about the computer code itself at all untested inputs. We model the output, as a function of its inputs, as a Gaussian process, and after a few initial runs of the code use a simulation approach to choose further suitable design points and to make inferences about the percentile of interest itself. An example is given involving a model that is used in sewer design.     

Raptor nesting locations along an urban density gradient in the Great Basin,USA

Raptors are the most prevalent group of urban apex predators, and the majority of raptor genera in North America have been recorded using urban areas. Prior research assessments along urban-wildland gradients show that urban habitat preference varies by raptor species and that raptor nesting preferences within urban settings may vary. Attempts to understand the intra- and inter-specific nesting patterns along an urban gradient would advance extant knowledge. Here we present the locations of individual nest sites of nine raptor species along an urban gradient in Reno-Sparks, NV. We developed an urban density model based on the number of residents, number of employees, and building footprints and number of floors for built structures within each land parcel at four spatial scales, representing nest site, macrohabitat, average nearest-nest, and landscape scales. Cooper’s Hawks (Accipiter cooperii), Sharp-shinned Hawks (Accipiter striatus), and Red-tailed Hawks (Buteo jamaicensis) nested across the widest range of the urban spectrum and closest to the urban core, whereas Golden Eagles (Aquila chrysaetos) and Swainson’s Hawks (Buteo swainsonii) nested on the urban fringe. Urban density for all nest locations was lowest at the nest-site scale, and the highest at the average nearest-nest and landscape scales. Raptors tended to occupy a wide range of the building-area density spectrum but not the building-height or employee density spectrums indicative of the attractiveness of suburban habitat.

     

Traumatic Experiences and Drug Use by LGB Adolescents: A Critical Review of Minority Stress

High rates of illicit drug use found among lesbian, gay, and bisexual (LGB) adolescents are often attributed to unique and chronic traumatic events tied to sexual minority identity. Although initiation of drug use is relatively common within adolescence, little research contributes to our understanding of the disparities found among LGB adolescents. This review synthesized existing literature to determine if the minority stress model is applicable to LGB drug use disparities and fits within a trauma framework. Findings indicate that minority stress experiences have been inconsistently related to drug use among LGB adolescents. Implications for future research and practice are described.     

Metropolitan Influence and Land Use Competition in Potential Biomass Crop Production: A Spatial Demographic Analysis

Biomass is one alternative energy source that is currently being investigated to combat the growing U.S. dependence on foreign oil. In this study, we explore where traditional farming practices and metropolitan influence will compete for land use against farmland located in optimal biomass crop production zones. To date, no consideration of the impact of urbanization and human development has been taken into account. Here we make a take a seminal approach to examining this relationship given previous analyses. We use overlapping LISA statistics to identify significant clusters of counties facing competition for land use. To measure competition for land use in counties located within biomass zones circa 2000, we use population growth and housing data from Census Bureau estimates, farmland data from the Census of Agriculture, and remotely sensed land use/cover data from the United States Geological Survey. The implications of these factors and how they will potentially affect biomass crop production are discussed.     

Editorial

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations -     

The Ties That Divide: Bonding Social Capital,Religious Friendship Networks,and Political Tolerance among Evangelicals*

Previous research has overwhelmingly found that Evangelical Protestants are generally less tolerant of outsiders than those of other religious traditions such as Catholics or Mainline Protestants. Using data from the 2005 Baylor Religion Survey, I examine the extent to which political tolerance is related to a bonding type of social capital that is typical of Evangelical Protestantism. Findings support most of the previous research into the relationship between religion and political tolerance, and support the hypothesis that social embeddedness within one’s congregation predicts intolerance among Evangelical Protestants, but not among those of other religious traditions. Implications for research into religious friendship networks and their potential dysfunctions are discussed.