632 research outputs found

    Parks & Equity: A Framework for Equitable Access in Richmond, VA Parks

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    Increasingly, cities are investing in their green spaces, such as open spaces and parks, as a strategy to improve the livability of the city, but also to improve the health of its residents. Research finds that access and proximity to green spaces provides a host of benefits to humans, including mental and physical health improvements. However, not all residents have equal access to these green public amenities. Research focuses on best practices for identifying minimum basic standards for DPR parks and the importance and limitations of green spaces in urban design. Basic standards include: setting the minimum limit for amenities in parks, best policies, implementation practices, and funding. The plan includes an analysis of the study area, Richmond, Virginia, and park access based on age, income, and race

    Conceptual design of a fleet of autonomous regolith throwing devices for radiation shielding of lunar habitats

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    The National Aeronautics and Space Administration (NASA) in conjunction with Universities Space Research Association (USRA) has requested that the feasibility of a fleet of regolith tossing devices designed to cover a lunar habitat for radiation protection be demonstrated. The regolith, or lunar soil, protects the lunar habitat and its inhabitants from radiation. Ideally, the device will operate autonomously in the lunar environment. To prove the feasibility of throwing regolith on the Moon, throwing solutions were compared to traditional, Earth-based methods for moving soil. Various throwing configurations were investigated. A linear throwing motion combined with a spring and motor energizing system proved a superior solution. Three different overall configurations for the lunar device are presented. A single configuration is chosen and critical parameters such as operating procedure, system volume, mass, and power are developed. The report is divided into seven main sections. First, the Introduction section gives background information, defines the project requirements and the design criteria, and presents the methodology used for the completion of this design. Next, the Preliminary Analysis section presents background information on characteristics of lunar habitats and the lunar environment. Then, the Alternate Designs section presents alternate solutions to each of the critical functions of the device. Fourth, a detailed analysis of throwing the regolith is done to demonstrate its feasibility. Then, the three overall design configurations are presented. Next, a configuration is selected and the conceptual design is expanded to include system performance characteristics, size, and mass. Finally, the Conclusions and Recommendations for Future Work section evaluates the design, outlines the next step to be taken in the design process, and suggests possible goals for future design work

    A new dromaeosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Wulansuhai Formation of Inner Mongolia, China

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    We describe a new dromaeosaurid theropod from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Inner Mongolia. The new taxon, Linheraptor exquisitus gen. et sp. nov., is based on an exceptionally well-preserved, nearly complete skeleton. This specimen represents the fifth dromaeosaurid taxon recovered from the Upper Cretaceous Djadokhta Formation and its laterally equivalent strata, which include the Wulansuhai Formation, and adds to the known diversity of Late Cretaceous dromaeosaurids. Linheraptor exquisitus closely resembles the recently reported Tsaagan mangas. Uniquely among dromaeosaurids, the two taxa share a large, anteriorly located maxillary fenestra and a contact between the jugal and the squamosal that excludes the postorbital from the infratemporal fenestra. These features suggest a sister-taxon relationship between L. exquisitus and T. mangas, which indicates the presence of a unique dromaeosaurid lineage in the Late Cretaceous of Asia. A number of cranial and dental features seen in L. exquisitus and T. mangas, and particularly some postcranial features of L. exquisitus, suggest that these two taxa are probably intermediate in systematic position between known basal and derived dromaeosaurids. The discovery of Linheraptor exquisitus is thus important for understanding the evolution of some salient features seen in the derived dromaeosaurids

    DIFFERENTIATING THE NECHES RIVER ROSE MALLOW (HIBISCUS DASYCALYX) FROM ITS CONGENERS BY MEANS OF PHYLOGENETICS AND POPULATION GENETICS

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    This study used molecular phylogenetic methods to attempt to resolve the taxonomic status of the federally threatened East Texas-endemic wildflower, the Neches River Rose Mallow (Hibiscus dasycalyx). Hibiscus dasycalyx co-occurs with two other closely related congeners that are currently not of conservation concern: the halberdleaf rose mallow (H. laevis); and the crimson-eyed rose mallow (H. moscheutos). This study assessed the phylogeny of these three Hibiscus species, and attempted to determine if there is possible hybridization occurring between them. To this end, Restriction Site Associated DNA Sequencing (RAD-Seq), a Next Generation Sequencing method, was used to generate genome-wide polymorphic genetic data. Two phylogenies were constructed utilizing Maximum Likelihood and Bayesian coalescence approaches. The Maximum likelihood phylogeny identified H. dasyclayx, H. laevis, and H. moscheutos as distinct monophyletic taxa. The Bayesian coalescence approach suggested H. moscheutos is a monophyletic sister clade to Hibiscus laevis, but suggested that H. dasycalyx and H. laevis are one monophyletic group and that H. dasycalyx is paraphyletic. AMOVAs did not show significant levels of admixture occurring between H. laevis, H. moscheutos, and H. dasycalyx. Bayesian clustering implemented in STRUCTURE was used determine the species relationships and gene flow between species, and revealed that H. dasycalyx clusters separately from H. laevis, and that the two species were differentiated from each other in this analysis with no evidence of admixture. The results overall do not have enough support to suggest the need, nor at the same time discredit a reclassification of H. dasycalyx. Further analysis of H. dasycalyx and H. laevis are needed to help better understand the taxonomic relationship between them

    Norrell H. Noble to Dr. Silver, 5 August 1962

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    Professional correspondenc

    Norrell H. Noble to Dr. Silver, 12 July 1962

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    Professional correspondenc

    Norrell to Dr. Silver, 15 June 1963

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    Personal correspondenc

    Development of Genomic Resources for the Evaluation of Red Snapper, an Emerging Species Candidate for Marine Aquaculture and Stock Enhancement

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    The northern red snapper (Lutjanus campechanus) is a highly targeted reef fish candidate for marine aquaculture and stock enhancement in the southern United States. This work aimed to develop genomic resources for the genetic management of aquaculture programs and to investigate population structure using high-throughput sequencing technologies. Eighty-four new microsatellite markers were developed through screening of Illumina paired-end sequencing reads. Microsatellite loci and Single Nucleotide Polymorphisms (SNPs) generated through Restriction Site Associated DNA (RAD) sequencing were assayed in 5 outbred full-sib families to construct a high-density linkage map of the red snapper genome. The map consists of 7,964 markers distributed across 24 linkage groups and was used to anchor genome contigs obtained during assembly of P-454 and Illumina sequencing reads. Genetic variation among four geographic populations of northern red snapper and one population of southern red snapper (Lutjanus purpureus) was studied using 6,890 SNPs generated by RAD sequencing. Northern and southern red snapper diverged significantly (average FST estimate 0.188) and Bayesian clustering suggested a complete lack of current gene flow between the two taxa. These results, coupled with the finding of divergent selection impacting several genomic regions during sliding window analysis, suggests that northern and southern red snapper should, at minimum, be managed as distinct population segments. Little evidence of population subdivision was found among northern red snapper populations, consistent with previous genetic studies. Further work is needed to improve the draft reference genome and estimate dispersal parameters in order to design management units for U.S. populations
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