5,557 research outputs found

    Strategic Alliances in U.S. Branded Beef Programs

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    In this paper, we combine concepts from organizational economics to examine supply chain alliances formed to market branded beef products. To illustrate application of the framework, we examine three different types of alliances. We conclude that measuring costs associated with quality attributes have an important role in alliance structure.Agribusiness,

    Effects of Leaf Diversity on Tannin Concentration and Water Quality

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    The abstract for this presentation can be downloaded by clicking on the blue download button

    Specific targeting of cytosine methylation to DNA sequences in vivo

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    Development of methods that will allow exogenous imposition of inheritable gene-specific methylation patterns has potential application in both therapeutics and in basic research. An ongoing approach is the use of targeted DNA methyltransferases, which consist of a fusion between gene-targeted zinc-finger proteins and prokaryotic DNA cytosine methyltransferases. These enzymes however have so far demonstrated significant and unacceptable levels of non-targeted methylation. We now report the development of second-generation targeted methyltransferase enzymes comprising enhanced zinc-finger arrays coupled to methyltransferase mutants that are functionally dominated by their zinc-finger component. Both in vitro plasmid methylation studies and a novel bacterial assay reveal a high degree of target-specific methylation by these enzymes. Furthermore, we demonstrate for the first time transient expression of targeted cytosine methyltransferase in mammalian cells resulting in the specific methylation of a chromosomal locus. Importantly, the resultant methylation pattern is inherited through successive cell divisions

    Use of altered-specificity binding Oct-4 suggests an absence of pluripotent cell-specific cofactor usage

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    Oct-4 is a POU domain transcription factor that is critical for maintaining pluripotency and for stem cell renewal. Previous studies suggest that transcription regulation by Oct-4 at particular enhancers requires the input of a postulated E1A-like cofactor that is specific to pluripotent cells. However, such studies have been limited to the use of enhancer elements that bind other POU-protein family members in addition to Oct-4, thus preventing a ‘clean’ assessment of any Oct-4:cofactor relationships. Other attempts to study Oct-4 functionality in a more ‘stand-alone’ situation target Oct-4 transactivation domains to DNA using heterologous binding domains, a methodology which is known to generate artificial data. To circumvent these issues, an altered-specificity binding Oct-4 (Oct-4RR) and accompanying binding site, which binds Oct-4RR only, were generated. This strategy has previously been shown to maintain Oct-1:cofactor interactions that are highly binding-site and protein/binding conformation specific. This system therefore allows a stand-alone study of Oct-4 function in pluripotent versus differentiated cells, without interference from endogenous POU factors and with minimal deviation from bound wild-type protein characteristics. Subsequently, it was demonstrated that Oct-4RR and the highly transactive regions of its N-terminus determined here, and its C-terminus, have the same transactivation profile in pluripotent and differentiated cells, thus providing strong evidence against the existence of such a pluripotent cell-specific Oct-4 cofactor

    No. 3, The Hooper Site (40DV234), A Mississippian Village in Davidson County, Tennessee

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    https://digitalcommons.memphis.edu/govpubs-tn-dept-environment-conservation-archaeology-miscellaneous/1002/thumbnail.jp

    Simulated annealing and greedy search for multi-objective optimisation

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    Copyright © 2009 University of ExeterSimulated annealing generalises greedy or elitist search methods by permitting states which are not an improvement over previous solutions, and for single-objective problems these exploratory moves permit escape from local minima. We examine two classes of multi-objective simulated annealing algorithm: those in which a single solution comprises the state and those in which a set of mutually non-dominating solutions form the state. We compare ways of determining the `energy' of the state in simulated annealing, including the dominated volume and we relate the greedy versions of these annealers (zero computational temperature) to well-established multi-objective optimisation algorithms. Empirical tests on the DTLZ test problems show that (a) a single solution state is often more efficient than a set-based state; and (b) that exploratory algorithms are out-performed by their greedy counterparts. These results lead to an examination of the role of local fronts. Problems for which the Pareto front cannot be located via a sequence of infinitesimal perturbations are defined to be noninfinitesimally greedy searchable. We present examples of non-infinitesimally greedy searchable test problems, which are nonetheless searchable using finite perturbations, but which may be adjusted to be arbitrarily hard even with large finite perturbations.Department of Computer Science, University of Exete

    Dominance Measures for Multi-Objective Simulated Annealing

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    Copyright © 2004 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Simulated annealing (SA) is a provably convergent optimiser for single-objective (SO) problems. Previously proposed MO extensions have mostly taken the form of an SO SA optimising a composite function of the objectives. We propose an MO SA utilising the relative dominance of a solution as the system energy for optimisation, eliminating problems associated with composite objective functions. We also propose a method for choosing perturbation scalings promoting search both towards and across the Pareto front.We illustrate the SA's performance on standard test problems. The new SA is shown to promote rapid convergence to the true Pareto front with a good coverage of points across it

    RHESSI Spectral Fits of Swift GRBs

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    One of the challenges of the Swift era has been accurately determining Epeak for the prompt GRB emission. RHESSI, which is sensitive from 30 keV to 17 MeV, can extend spectral coverage above the Swift-BAT bandpass. Using the public Swift data, we present results of joint spectral fits for 26 bursts co-observed by RHESSI and Swift-BAT through May 2007. We compare these fits to estimates of Epeak which rely on BAT data alone. A Bayesian Epeak estimator gives better correspondence with our measured results than an estimator relying on correlations with the Swift power law indices.Comment: 4 pages, 1 figure. To appear in the proceedings of Gamma Ray Bursts 2007, Santa Fe, New Mexico, November 5-9 200

    The Locus Algorithm: A novel technique for identifying optimised pointings for differential photometry

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    Studies of the photometric variability of astronomical sources from ground-based telescopes must overcome atmospheric extinction effects. Differential photometry by reference to an ensemble of reference stars which closely match the target in terms of magnitude and colour can mitigate these effects. This Paper describes the design, implementation, and operation of a novel algorithm – The Locus Algorithm – which enables optimised differential photometry. The Algorithm is intended to identify, for a given target and observational parameters, the Field of View (FoV) which includes the target and the maximum number of reference stars similar to the target. A collection of objects from a catalogue (e.g. SDSS) is filtered to identify candidate reference stars and determine a rating for each which quantifies its similarity to the target. The algorithm works by defining a locus of points around each candidate reference star, upon which the FoV can be centred and include the reference at the edge of the FoV. The Points of Intersection (PoI) between these loci are identified and a score for each PoI is calculated. The PoI with the highest score is output as the optimum pointing. The steps of the algorithm are precisely defined in this paper. The application of The Locus Algorithm to a sample target, SDSS1237680117417115655, from the Sloan Digital Sky Survey is described in detail. The algorithm has been defined here and implemented in software which is available online. The algorithm has also been used to generate catalogues of pointings to optimise Quasar variability studies and to generate catalogues of optimised pointings in the search for Exoplanets via the transit method

    AWIPS II Application Development, a SPoRT Perspective

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    The National Weather Service (NWS) is deploying its nextgeneration decision support system, called AWIPS II (Advanced Weather Interactive Processing System II). NASA's Shortterm Prediction Research and Transition (SPoRT) Center has developed several software 'plugins' to extend the capabilities of AWIPS II. SPoRT aims to continue its mission of improving shortterm forecasts by providing NASA and NOAA products on the decision support system used at NWS weather forecast offices (WFOs). These products are not included in the standard Satellite Broadcast Network feed provided to WFOs. SPoRT has had success in providing support to WFOs as they have transitioned to AWIPS II. Specific examples of transitioning SPoRT plugins to WFOs with newly deployed AWIPS II systems will be presented. Proving Ground activities (GOESR and JPSS) will dominate SPoRT's future AWIPS II activities, including tool development as well as enhancements to existing products. In early 2012 SPoRT initiated the Experimental Product Development Team, a group of AWIPS II developers from several institutions supporting NWS forecasters with innovative products. The results of the team's spring and fall 2013 meeting will be presented. Since AWIPS II developers now include employees at WFOs, as well as many other institutions related to weather forecasting, the NWS has dealt with a multitude of software governance issues related to the difficulties of multiple remotely collaborating software developers. This presentation will provide additional examples of ResearchtoOperations plugins, as well as an update on how governance issues are being handled in the AWIPS II developer community
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