894 research outputs found

    Vibration characteristics of ring-stiffened orthotropic shells of revolution

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    Computer program solves vibration modes and frequencies of thin shells of revolution having general meridional curvature and orthotropic elastic properties in order to evaluate the dynamic behavior of structures with thin shelled components

    Towards a publicly available, map-based regional software tool to estimate unregulated daily streamflow at ungauged rivers

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    Streamflow information is critical for addressing any number of hydrologic problems. Often, streamflow information is needed at locations that are ungauged and, therefore, have no observations on which to base water management decisions. Furthermore, there has been increasing need for daily streamflow time series to manage rivers for both human and ecological functions. To facilitate negotiation between human and ecological demands for water, this paper presents the first publicly available, map-based, regional software tool to estimate historical, unregulated, daily streamflow time series (streamflow not affected by human alteration such as dams or water withdrawals) at any user-selected ungauged river location. The map interface allows users to locate and click on a river location, which then links to a spreadsheet-based program that computes estimates of daily streamflow for the river location selected. For a demonstration region in the northeast United States, daily streamflow was, in general, shown to be reliably estimated by the software tool. Estimating the highest and lowest streamflows that occurred in the demonstration region over the period from 1960 through 2004 also was accomplished but with more difficulty and limitations. The software tool provides a general framework that can be applied to other regions for which daily streamflow estimates are needed

    Learning to Look With One Eye: The Use of Head Turn by Normals and Strabismics

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    AbstractWhen asked to look through a tube, young children (normal, strabismic, monocularly enucleated) place it between the eyes, while older children turn the head or shut one eye. We videotaped 174 children (normals and strabismics, 2–17 yr of age) and 16 normal adults to find out when and why head turn occurs. In learning to look with one eye, children progressed through a sequence of four responses, categorized by age or amount of head turn. Binocular children use head turn apparently to avoid diplopia, then, most learn to shut one eye. Adults, forced to use the “non-preferred” eye, revert to turning the head. Copyright © 1996 Elsevier Science Ltd

    Effect of Mytilus coruscus selective filtration on phytoplankton assemblages

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    The feeding selectivity of bivalves can play an important role in shaping the structure of phytoplankton communities of natural waters. This could be particularly true in waters with intensive bivalves farming, like Sungo Bay, Northern China. Understanding the role of bivalve feeding behavior is important for assessing how the dense cultivation of bivalves may affect phytoplankton community composition and food web structure in farm areas. In this study, we investigated the feeding selectivity of blue mussel Mytilus coruscus on natural phytoplankton assemblages in Sungo Bay using both optical microscopy and HPLC-pigment analysis. Results showed that cryptophytes dominated the phytoplankton community and made up 66.1% of the total phytoplankton abundance. A comparison of phytoplankton composition between natural and filtered seawater showed that M. coruscus preferred cryptophytes and dinoflagellates than Chaetoceros spp. and Skeletonema spp. Cryptophytes were not detected in gut contents by microscopic observation, while their marker pigment alloxanthin was present, suggesting they were also consumed by M. coruscus and can be readily digested. This highlights the shortcomings of microscopic methods and the significance of HPLC-pigment analysis in obtaining a comprehensive understanding of feeding selectivity of bivalves. The proportions of Chaetoceros spp. and Skeletonema spp. in gut contents were significantly lower than their proportions in the seawater, and contrastingly, the proportions of Cocconeis spp. and Pinnularia spp. showed opposite patterns. The marker pigments prasinoxanthin and zeaxanthin were detected in the gut of M. coruscus indicating that picophytoplankton (e.g., prasinophytes and Synechococcus) are also food sources for this bivalve. This information furthers our understanding of bivalve aquaculture and environment interactions.publishedVersio

    Reference Genomes from Distantly Related Species Can Be Used for Discovery of Single Nucleotide Polymorphisms to Inform Conservation Management

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    Threatened species recovery programmes benefit from incorporating genomic data into conservation management strategies to enhance species recovery. However, a lack of readily available genomic resources, including conspecific reference genomes, often limits the inclusion of genomic data. Here, we investigate the utility of closely related high-quality reference genomes for single nucleotide polymorphism (SNP) discovery using the critically endangered kakī/black stilt (Himantopus novaezelandiae) and four Charadriiform reference genomes as proof of concept. We compare diversity estimates (i.e., nucleotide diversity, individual heterozygosity, and relatedness) based on kakī SNPs discovered from genotyping-by-sequencing and whole genome resequencing reads mapped to conordinal (killdeer, Charadrius vociferus), confamilial (pied avocet, Recurvirostra avosetta), congeneric (pied stilt, Himantopus himantopus) and conspecific reference genomes. Results indicate that diversity estimates calculated from SNPs discovered using closely related reference genomes correlate significantly with estimates calculated from SNPs discovered using a conspecific genome. Congeneric and confamilial references provide higher correlations and more similar measures of nucleotide diversity, individual heterozygosity, and relatedness. While conspecific genomes may be necessary to address other questions in conservation, SNP discovery using high-quality reference genomes of closely related species is a cost-effective approach for estimating diversity measures in threatened species

    A Youth-Leader Program in Baltimore City Recreation Centers: Lessons Learned and Applications

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    Peer-led interventions may be an effective means of addressing the childhood obesity epidemichowever, few studies have looked at the long-term sustainability of such programs. As part of a multilevel obesity prevention intervention, B'More Healthy Communities for Kids, 16 Baltimore college students were trained as youth-leaders (YLs) to deliver a skill-based nutrition curriculum to low-income African American children (10-14 years old). In April 2015, formative research was used to inform sustainability of the YL program in recreation centers. In-depth interviews were conducted with recreation center directors (n = 4) and the YLs (n = 16). Two focus groups were conducted with YLs (n = 7) and community youth-advocates (n = 10). Barriers to this program included difficulties with transportation, time constraints, and recruiting youth. Lessons learned indicated that improving trainings and incentives to youth were identified as essential strategies to foster continuity of the youth-led program and capacity building. High school students living close to the centers were identified as potential candidates to lead the program. Based on our findings, the initial intervention will be expanded into a sustainable model for implementation, using a train-the-trainer approach to empower community youth to be change agents of the food environment and role models.Johns Hopkins Urban Health InstituteGlobal Obesity Prevention Center at Johns HopkinsEunice Kennedy Shriver National Institute of Child Health and Human DevelopmentOffice of the Director, National Institutes of Health [U54HD070725]646 CNPq [GDE: 249316/2013-7]Johns Hopkins Bloomberg Sch Publ Hlth, Baltimore, MD USAUniv Tennessee, Knoxville, TN USAUniv Fed Sao Paulo, Santos, SP, BrazilDept Recreat & Pk City Baltimore, Baltimore, MD USAUniv Maryland Extens, Ellicott City, MD USAUniv Fed Sao Paulo, Santos, SP, BrazilWeb of Scienc
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