5,059 research outputs found

    Surveying on the Side: A Study in the Implementation of a Tilted Multibeam Transducer in an Ultra-Shallow Riverine Environment

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    In 2008, students of the University of Southern Mississippi surveyed a portion of the Pearl River. Due to the ultra-shallow nature of the survey area, a multibeam mount was constructed that tilted the transducer 35o to the side with respect to nadir. Such an orientation had predicted gains of 60% in the center of the channel and facilitated the collection of data further inshore than otherwise possible. To compensate for excessive outer beam noise, a CUBE surface filtering regime was adopted. Crosscheck analysis showed the acquired data easily met IHO S-44 1a standards. This paper details the evaluation and results of such a non-traditional mount.En el 2008, unos alumnos de la Universidad del Sur de Misisipí levantaron un sector del Río Pearl. Debido a la naturaleza de las aguas ultra-someras de la zona del levantamiento, una estructura multihaz fue construida de forma tal que el transductor se inclinaba a 35° con respecto al nadir. Una orientación similar había pronosticado aumentos del 60 % en el centro del canal y facilitó la recogida de datos más cerca de la costa, que era posible de otra forma. Para compensar el exceso de ruido del haz externo, se adoptó un régimen “CUBE” de filtrado de superficie. El análisis de verificaciones cruzadas mostró que los datos obtenidos cumplían fácilmente la norma S-44 de la OHI. Este documento detalla la evaluación y los resultados de un montaje similar no tradicional.En 2008, des étudiants de l’University of Southern Mississippi ont exécuté des levés hydrographiques dans une partie du fleuve Pearl. En raison de la nature extrêmement peu profonde de la zone hydrographiée, une structure multifaisceaux a été construite de manière à ce que le transduceur soit incliné de 35° par rapport au nadir. Cette orientation avait permis de prévoir une augmentation de 60% au centre du canal et permis la collecte de données plus proches de la côte que ce qui aurait été possible, autrement. Afin de compenser le bruit excessif du faisceau externe, un régime de filtrage de surface CUBE a été adopté. L’analyse par recoupement a montré que les données acquises étaient sans nul doute conformes à la S-44 de l’OHI. Cet article donne le détail de l’évaluation et des résultats de ce type de structure non traditionnelle

    Is Quantitative Research Ethical? Tools for Ethically Practicing, Evaluating, and Using Quantitative Research

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    This editorial offers new ways to ethically practice, evaluate, and use quantitative research (QR). Our central claim is that ready-made formulas for QR, including 'best practices' and common notions of 'validity' or 'objectivity,' are often divorced from the ethical and practical implications of doing, evaluating, and using QR for specific purposes. To focus on these implications, we critique common theoretical foundations for QR and then recommend approaches to QR that are 'built for purpose,' by which we mean designed to ethically address specific problems or situations on terms that are contextually relevant. For this, we propose a new tool for evaluating the quality of QR, which we call 'relational validity.' Studies, including their methods and results, are relationally valid when they ethically connect researchers' purposes with the way that QR is oriented and the ways that it is done—including the concepts and units of analysis invoked, as well as what its 'methods' imply more generally. This new way of doing QR can provide the liberty required to address serious worldly problems on terms that are both practical and ethically informed in relation to the problems themselves rather than the confines of existing QR logics and practices.cited By

    Genetic Detection and a Method to Study the Ecology of Deadly Cubozoan Jellyfish

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    Cubozoan jellyfish pose a risk of envenomation to humans and a threat to many businesses, yet crucial gaps exist in determining threats to stakeholders and understanding their ecology. Environmental DNA (eDNA) provides a cost-effective method for detection that is less labour intensive and provides a higher probability of detection. The objective of this study was to develop, optimise and trial the use of eDNA to detect the Australian box jellyfish, Chironex fleckeri. This species was the focus of this study as it is known to have the strongest venom of any cubozoan; it is responsible for more than 200 recorded deaths in the Indo-Pacific region. Further, its ecology is poorly known. Herein, a specific and sensitive probe-based assay, multiplexed with an endogenous control assay, was developed, and successfully utilised to detect the deadly jellyfish species and differentiate them from closely related taxa. A rapid eDNA decay rate of greater than 99% within 27 h was found with no detectable influence from temperature. The robustness of the technique indicates that it will be of high utility for detection and to address knowledge gaps in the ecology of C. fleckeri; further, it has broad applicability to other types of zooplankton

    The phosphoinositide 3-kinase-dependent activation of Btk is required for optimal eicosanoid production and generation of reactive oxygen species in antigen-stimulated mast cells

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    Activated mast cells are a major source of the eicosanoids PGD(2) and leukotriene C(4) (LTC(4)), which contribute to allergic responses. These eicosanoids are produced following the ERK1/2-dependent activation of cytosolic phospholipase A(2), thus liberating arachidonic acid, which is subsequently metabolized by the actions of 5-lipoxygenase and cyclooxygenase to form LTC(4) and PGD(2), respectively. These pathways also generate reactive oxygen species (ROS), which have been proposed to contribute to FcepsilonRI-mediated signaling in mast cells. In this study, we demonstrate that, in addition to ERK1/2-dependent pathways, ERK1/2-independent pathways also regulate FcepsilonRI-mediated eicosanoid and ROS production in mast cells. A role for the Tec kinase Btk in the ERK1/2-independent regulatory pathway was revealed by the significantly attenuated FcepsilonRI-dependent PGD(2), LTC(4), and ROS production in bone marrow-derived mast cells of Btk(-/-) mice. The FcepsilonRI-dependent activation of Btk and eicosanoid and ROS generation in bone marrow-derived mast cells and human mast cells were similarly blocked by the PI3K inhibitors, Wortmannin and LY294002, indicating that Btk-regulated eicosanoid and ROS production occurs downstream of PI3K. In contrast to ERK1/2, the PI3K/Btk pathway does not regulate cytosolic phospholipase A(2) phosphorylation but rather appears to regulate the generation of ROS, LTC(4), and PGD(2) by contributing to the necessary Ca(2+) signal for the production of these molecules. These data demonstrate that strategies to decrease mast cell production of ROS and eicosanoids would have to target both ERK1/2- and PI3K/Btk-dependent pathways

    Readily accessible sp3-rich cyclic hydrazine frameworks exploiting nitrogen fluxionality

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    Increased molecular complexity correlates with improved chances of success in the drug development process. Here, a strategy for the creation of sp3-rich, non-planar heterocyclic scaffolds suitable for drug discovery is described that obviates the need to generate multiple stereogenic centers with independent control. Asymmetric transfer hydrogenation using a tethered Ru-catalyst is used to efficiently produce a range of enantiopure cyclic hydrazine building blocks (up to 99% ee). Iterative C–N functionalization at the two nitrogen atoms of these compounds produces novel hydrazine and hydrazide based chemical libraries. Wide chemical diversification is possible through variation in the hydrazine structure, use of different functionalization chemistries and coupling partners, and controlled engagement of each nitrogen of the hydrazine in turn. Principal Moment of Inertia (PMI) analysis of this small hydrazine library reveals excellent shape diversity and three-dimensionality. NMR and crystallographic studies confirm these frameworks prefer to orient their substituents in three-dimensional space under the control of a single stereogenic center through exploitation of the fluxional behavior of the two nitrogen atoms

    The Relationship Between Multicast Applications and Scatter/Gather I/O

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    Perfect algorithms and e-business have garnered great interest from both security experts and cyberneticists in the last several years. Given the trends in authenticated technology, programmers dubiously note the intuitive unification of I/O automata and linked lists. We introduce new robust configurations (Amass), arguing that thin clients and expert systems can interact to achieve this purpose
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