368 research outputs found

    Optimization of a Non-traditional Unsupervised Classification Approach for Land Cover Analysis

    Get PDF
    The conditions under which a hybrid of clustering and canonical analysis for image classification produce optimum results were analyzed. The approach involves generation of classes by clustering for input to canonical analysis. The importance of the number of clusters input and the effect of other parameters of the clustering algorithm (ISOCLS) were examined. The approach derives its final result by clustering the canonically transformed data. Therefore the importance of number of clusters requested in this final stage was also examined. The effect of these variables were studied in terms of the average separability (as measured by transformed divergence) of the final clusters, the transformation matrices resulting from different numbers of input classes, and the accuracy of the final classifications. The research was performed with LANDSAT MSS data over the Hazleton/Berwick Pennsylvania area. Final classifications were compared pixel by pixel with an existing geographic information system to provide an indication of their accuracy

    Tarphonomus, a new genus of ovenbird (Aves: Passeriformes: Furnariidae) from South America

    Get PDF
    Tarphonomus, a new genus of ovenbird (Aves: Passeriformes: Furnariidae) from South America, is described. Species included in the new genus, formerly placed in Upucerthia, are T. certhioides and T. harterti

    Genomic insights into adaptation to high-altitude environments

    Get PDF
    Elucidating the molecular genetic basis of adaptive traits is a central goal of evolutionary genetics. The cold, hypoxic conditions of high-altitude habitats impose severe metabolic demands on endothermic vertebrates, and understanding how high-altitude endotherms cope with the combined effects of hypoxia and cold can provide important insights into the process of adaptive evolution. The physiological responses to high-altitude stress have been the subject of over a century of research, and recent advances in genomic technologies have opened up exciting opportunities to explore the molecular genetic basis of adaptive physiological traits. Here, we review recent literature on the use of genomic approaches to study adaptation to high-altitude hypoxia in terrestrial vertebrates, and explore opportunities provided by newly developed technologies to address unanswered questions in high-altitude adaptation at a genomic scale. © 2012 Macmillan Publishers Limited All rights reserved

    Inferring Species Trees Directly from Biallelic Genetic Markers: Bypassing Gene Trees in a Full Coalescent Analysis

    Get PDF
    The multi-species coalescent provides an elegant theoretical framework for estimating species trees and species demographics from genetic markers. Practical applications of the multi-species coalescent model are, however, limited by the need to integrate or sample over all gene trees possible for each genetic marker. Here we describe a polynomial-time algorithm that computes the likelihood of a species tree directly from the markers under a finite-sites model of mutation, effectively integrating over all possible gene trees. The method applies to independent (unlinked) biallelic markers such as well-spaced single nucleotide polymorphisms (SNPs), and we have implemented it in SNAPP, a Markov chain Monte-Carlo sampler for inferring species trees, divergence dates, and population sizes. We report results from simulation experiments and from an analysis of 1997 amplified fragment length polymorphism (AFLP) loci in 69 individuals sampled from six species of {\em Ourisia} (New Zealand native foxglove)

    A GIS/GPS Approach For The Abondoned Mine Inventory Of The Monongahela National Forest Using Space Borne And Aerial Images For Basemap Selection

    Get PDF
    The Monongahela National Forest spans 10 counties in eastern central West Virginia. It has been an area of high mining and timbering activities throughout much of the early to mid twentieth century. As a result, the United States Forest Service (USFS) has focused reclamation and remediation efforts on the abandoned mine land areas. Much of the area has been subjected to mining after effects such as acid mine drainage, structural remains, gob/spoil piles, garbage piles, mine portals, and highwalls. In 1998 the USFS contracted with the U.S. Army Corps of Engineers (USACE) to provide a detailed georeferenced inventory with a Global Positioning System (GPS) for the mining remains previously mentioned. In addition, the inventory included quantitative descriptions and water quality data. A geobiophysical model containing the abandoned mine land features will provide the information necessary for appropriate steps toward reclamation of the area. The primary objective of this research creates a GIS database infrastructure for the Monongahela National Forest inventory integrating Landsat 7 +ETM 30 m and 15 m imagery, and USGS Digital Orthophoto Quarter Quadrangles (DOQQ\u27s), as a more modern image base map. This data base can then be used to simulate the resolution and visual effects that can be seen through high resolution space borne imagery such as IKONOS (Space Imaging, 2002) and Quickbird (Digital Globe, 2002). This, in comparison to the USGS Digital Raster Graphics (DRG) topographic maps, allows for more current geobiophysical modeling in a remote sensing system and provides an easily updated data management tool

    A Reference Genome For The Nectar-Robbing Black-Throated Flowerpiercer (Diglossa Brunneiventris)

    Get PDF
    Black-throated Flowerpiercers (Diglossa brunneiventris) are one species representing a phenotypically specialized group of tanagers (Thraupidae) that have hooked bills which allow them to feed by stealing nectar from the base of flowers. Members of the genus are widely distributed in montane regions from Mexico to northern Argentina, and previous studies of Diglossa have focused on their systematics, phylogenetics, and interesting natural history. Despite numerous studies of species within the genus, no genome assembly exists to represent these nectivorous tanagers. We described the assembly of a genome sequence representing a museum-vouchered, wild, female D. brunneiventris collected in Peru. By combining Pacific Biosciences Sequel long-read technology with 10x linked-read and reference-based scaffolding, we produced a 1.08 Gbp pseudochromosomal assembly including 600 scaffolds with a scaffold N50 of 67.3 Mbp, a scaffold L50 of 6, and a BUSCO completeness score of 95%. This new assembly improves representation of the diverse species that comprise the tanagers, improves on scaffold lengths and contiguity when compared to existing genomic resources for tanagers, and provides another avenue of research into the genetic basis of adaptations common to a nectivorous lifestyle among vertebrates

    Andean Land Use And Biodiversity: Humanized Landscapes In A Time Of Change

    Get PDF
    Some landscapes Cannot be understood without reference., to the kinds. degrees, kinds, degrees, and history of human-caused modifications to the Earth's surface. The tropical latitudes of the Andes represent one such place, with agricultural land-use systems appearing in the Early Holocene. Current land use includes both intensive and extensive grazing and crop- or tree-based agricultural systems found across virtually the, entire range of possible elevations and humidity regimes. Biodiversity found in or adjacent to such humanized landscapes will have been altered in abundance. composition, and distribution in relation to the resiliency of the native Species to harvest, hold cover modifications, and other deliberate or inadvertent human land uses. In addition, the geometries of land cover, resulting flout difference among the shapes, sizes, connectivities, and physical structures of the patches, corridors, and matrices that compose landscape mosaics, will constrain biodiversity, often in predictable ways. This article proposes a conceptual model that alter ins that the Continued persistence of native species may depend as much oil the shifting Of Andean landscape mosaics as on species characteristics, themselves. Furthermore, mountains such as the Andes display long gradients of environmental Conditions that after in relation to latitude, soil moisture, aspect, and elevation. Global environmental change will shift these, especially temperature and humidity regimes along elevational gradients, causing Changes outside the historical range of variation for some species. Both land-use systems and Conservation efforts will need to respond spatially to these shifts in the future, at both landscape and regional scales.Geography and the Environmen

    A Comparison of the Tensile and Bending Properties of Dental Gold Wires

    Full text link
    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68282/2/10.1177_00220345510300022001.pd
    corecore