24,414 research outputs found

    Excavations at the later prehistoric site of Lewan, North-West Frontier Province, Pakistan

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    "So bigge as bigge may be": tracking size and shape change in domestic livestock in London (AD 1220-1900)

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    This study presents the analysis of 7966 individual cattle, sheep, pig and domestic hen bone measurements from 105 sites excavated in London dating to the period AD 1220–1900. Multiple episodes of size change are identified, although the speed and timing varies by species. The earliest evidence for size change in cattle and sheep occurs in the early 14th century and may be connected to the need to restock livestock populations following the outbreaks of murrain in the first half of that century. Subsequent size increases in livestock size may have occurred as a combined consequence of agricultural innovations in the wake of the Black Death, the increasing commercialisation of animal farming, as the meat requirements of an expanding London grew, and the rise of the ethic of improvement

    An experimental design approach to the chemical characterisation of pectin polysaccharides extracted from Cucumis melo Inodorus

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    Extracted pectins have been utilised in a number of applications in both the food and pharmaceutical industries where they are generally used as gelling agents, thickeners and stabilisers, although a number of pectins have been shown to be bioactive. These functional properties will depend upon extraction conditions. A statistical experimental design approach was used to study the effects of extraction conditions pH, time and temperature on pectins extracted from Cucumis melo Inodorus. The results show that the chemical composition is very sensitive to these conditions and that this has a great influence on for example the degree of branching. Higher temperatures, lower pHs and longer extraction times lead to a loss of the more acid labile arabinofuranose residues present on the pectin side chain. The fitting of regression equations relating yield and composition to extraction conditions can therefore lead to tailor-made pectins for specific properties and/ or applications

    Monodromy Substitutions and Rational Blowdowns

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    We introduce several new families of relations in the mapping class groups of planar surfaces, each equating two products of right-handed Dehn twists. The interest of these relations lies in their geometric interpretation in terms of rational blowdowns of 4-manifolds, specifically via monodromy substitution in Lefschetz fibrations. The simplest example is the lantern relation, already shown by the first author and Gurtas to correspond to rational blowdown along a -4 sphere; here we give relations that extend that result to realize the "generalized" rational blowdowns of Fintushel-Stern and Park by monodromy subsitution, as well as several of the families of rational blowdowns discovered by Stipsicz-Szab\'o-Wahl.Comment: 28 pages, many figures. v2: minor edits; this version accepted for publication in Journal of Topolog

    Implicit Bias and the School to Prison Pipeline

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    Deploying Jupyter Notebooks at scale on XSEDE resources for Science Gateways and workshops

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    Jupyter Notebooks have become a mainstream tool for interactive computing in every field of science. Jupyter Notebooks are suitable as companion applications for Science Gateways, providing more flexibility and post-processing capability to the users. Moreover they are often used in training events and workshops to provide immediate access to a pre-configured interactive computing environment. The Jupyter team released the JupyterHub web application to provide a platform where multiple users can login and access a Jupyter Notebook environment. When the number of users and memory requirements are low, it is easy to setup JupyterHub on a single server. However, setup becomes more complicated when we need to serve Jupyter Notebooks at scale to tens or hundreds of users. In this paper we will present three strategies for deploying JupyterHub at scale on XSEDE resources. All options share the deployment of JupyterHub on a Virtual Machine on XSEDE Jetstream. In the first scenario, JupyterHub connects to a supercomputer and launches a single node job on behalf of each user and proxies back the Notebook from the computing node back to the user's browser. In the second scenario, implemented in the context of a XSEDE consultation for the IRIS consortium for Seismology, we deploy Docker in Swarm mode to coordinate many XSEDE Jetstream virtual machines to provide Notebooks with persistent storage and quota. In the last scenario we install the Kubernetes containers orchestration framework on Jetstream to provide a fault-tolerant JupyterHub deployment with a distributed filesystem and capability to scale to thousands of users. In the conclusion section we provide a link to step-by-step tutorials complete with all the necessary commands and configuration files to replicate these deployments.Comment: 7 pages, 3 figures, PEARC '18: Practice and Experience in Advanced Research Computing, July 22--26, 2018, Pittsburgh, PA, US

    Invasive Diseases and Fruit Tree Production: Economic Tradeoffs of Citrus Greening Control on Florida's Citrus Industry

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    An investment model of Florida oranges was used to evaluate various management strategies for controlling Huanglongbing, or citrus greening, a highly destructive disease. This analysis will enable the Florida citrus industry to make more informed decisions about the economic tradeoffs among current citrus greening management alternatives.Crop Production/Industries,
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