2,124 research outputs found

    On The Integral Coding Advantage In Unit Combination Networks

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    Network coding is a networking paradigm which allows network nodes to combine different pieces of data at various steps in the transmission rather than simply copying and forwarding the data. Network coding has various applications, and can be used to increase throughput, routing efficiency, robustness, and security. The original benefit that was demonstrated was improving the allowable transmission rate for a multicast session, and this application has been the focus of much research. One important parameter, the coding advantage, is the ratio of throughput with network coding to that without. The multicast networks that have a non-trivial coding advantage (i.e., coding advantage greater than 1) all seem to contain a substructure called the combination network which has a source, n relay nodes, and n k receivers in which each receiver is adjacent to a unique subset of k relay nodes. The coding advantage in combination networks has previously been determined for networks with fractional routing. In this paper, we address integral routing, which is more appropriate for networks (like optical wavelength-division-multiplexing networks) which allow only coarse-grained subdivision of the available bandwidth on any given channel. We give exact formulas for the integral coding advantage in both directed and undirected networks. For directed networks, we show that the coding advantage is k=n nk+1. For undirected networks, we show that the coding advantage is k=(k1). The latter result ts with conjectures that the integral coding advantage in any undirected network is bounded above by 2

    Effect of Metformin on miR-146a Expression

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    Sjögren’s Syndrome (SjS) is an autoimmune disorder that affects secretory glands in the human body, restricting their function and causing extreme dryness in areas like the mouth and eyes. miR-146a is an anti-inflammatory microRNA that targets the NFÎșB activation pathway. Previous studies have shown that SjS patients have increased miR-146a expression, despite having high levels of inflammation. The objective of this study was to investigate whether metformin, a diabetes drug with a wide variety of effects and potential functions, reduces levels of miR-146a expression. Metformin is known to reduce inflammation by inhibiting the activation of NFÎșB. THP-1 human monocytes were treated with various concentrations of metformin ranging from 12.5uM to 200uM. The cells were treated for 24 hours before total RNA was isolated, and qRT-PCR was utilized to compare miR-146a expression in metformin-treated versus untreated cells. Our results showed a dose-dependent decrease of miR-146a expression in the presence of metformin. These results are reasonable since miR-146a expression is dependent on NFÎșB activation, and metformin is known to inhibit the activation of NFÎșB. Further studies will investigate metformin’s ability to suppress inflammation in varying conditions

    Effects of Fluorescein Staining on Laser In Vivo Confocal Microscopy Images of the Cornea

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    This study was designed to identify whether topical fluorescein, a common ophthalmic tool, affects laser in vivo confocal microscopy of the cornea, a tool with growing applications. Twenty-five eye care specialists were asked to identify presence or absence of fluorescein in 99 confocal micrographs of healthy corneas. Responses were statistically similar to guessing for the epithelium (48% ± 14% of respondents correct per image) and the subbasal nerve plexus (49% ± 11% correct), but results were less clear for the stroma. Dendritic immune cells were quantified in bilateral images from subjects who had been unilaterally stained with fluorescein. Density of dendritic immune cells was statistically similar between the unstained and contralateral stained eyes of 24 contact lens wearers (P = .72) and of 10 nonwearers (P = .53). Overall, the results indicated that fluorescein staining did not interfere with laser confocal microscopy of corneal epithelium, subbasal nerves, or dendritic immune cells

    Differential Effects of Sodium and Magnesium Sulfate on Water Consumption by Beef Cattle

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    The existing guidelines for maximum sulfate (SO4) in cattle drinking water are based on Na2SO4, although many water sources contain greater concentrations of MgSO4. Two experiments compared the effect of different SO4 salts on water consumption and fecal DM of cattle. In Exp. 1, 8 yearling heifers (initial BW = 345 ± 8 kg; mean ± SD) were watered twice daily with tapwater or water containing Na2SO4 or MgSO4 at target levels of 1,500, 3,000, or 4,500 mg of SO4/L for 2-d treatment periods separated by 2 d of access to tapwater. In Exp. 2, 16 yearling cattle (initial BW = 421 ± 24 kg) were watered twice daily with tapwater (16 mg of SO4/L) or water containing Na2SO4 at target levels of 2,000 mg of SO4/L (low Na2SO4), MgSO4 at 2,000 mg of SO4/L (low MgSO4), or MgSO4 at 4,000 mg of SO4/L (high MgSO4) in 21-d treatment periods separated by 7-d periods on tapwater. The first 10 d of each period were allowed for adjustment to the treatment, and the final 11 d was considered the treatment period for analysis purposes. Treatments were applied in an incomplete Latin square, where each animal was exposed to 3 of the 4 treatments. In Exp. 1, the average daily water consumption decreased linearly as the SO4 concentration increased for MgSO4 (P = 0.0001) but not for Na2SO4 (P = 0.39). In Exp. 2, the average daily water consumption was less for cattle on the high-MgSO4 treatment than for cattle on the low-MgSO4 treatment (P = 0.0001), and cattle on the low-MgSO4 treatment tended (P = 0.09) to drink less than those on the tapwater treatment. Fecal DM was greater for cattle on the high-MgSO4 treatment than for those on the low-MgSO4 treatment (P \u3c 0.01). These findings indicate that cattle reduce their consumption of water containing high (≄ 4,000 mg of SO4/L) concentrations of MgSO4, even after a given time to adjust to the treatment; such reductions may be accompanied by an increase in fecal DM

    Software Solutions for Antenna Design Exploration: A Comparison of Packages, Tools, Techniques, and Algorithms for Various Design Challenges

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    Numerous software packages exist for solving antenna design optimization problems, with many of these employing a variety of approaches, leading, in turn, to variations in optimization performance. Antenna designers, often not fully schooled in optimization, can be confused as to which algorithm in which software package should be used. A wrong choice can cause the failure of the optimization or the expending of considerable time on the computationally expensive 3D electromagnetic (EM) simulations involved. While it is true that the various algorithms, combined with the variety of complex challenges found in different real-world scenarios make a direct comparison among tools difficult, a robust attempt at such an evaluation is overdue

    Hidrogenionic potential (pH) of the attractant, trap density and control threshold for Ceratitis capitata (Diptera: tephritidae) on Hamlin oranges in SĂŁo Paulo central region, Brazil

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    This study evaluated the effect of initial pH values of 4.5, 6.5 and 8.5 of the attractant (protein bait) MilhocinaÂź and borax (sodium borate) in the feld, on the capture of fruit ïŹ‚ies in McPhail traps, using 1, 2, 4 and 8 traps per hectare, in order to estimate control thresholds in a Hamlin orange grove in the central region of the state of SĂŁo Paulo. The most abundant fruit ïŹ‚y species was Ceratitis capitata, comprising almost 99% of the fruit ïŹ‚ies captured, of which 80% were females. The largest captures of C. capitata were found in traps baited with MilhocinaÂź and borax at pH 8.5. Captures per trap for the four densities were similar, indicating that the population can be estimated with one trap per hectare in areas with high populations. It was found positive relationships between captures of C. capitata and the number of Hamlin oranges damaged, 2 and 3 weeks after capture. It was obtained equations that correlate captures and damage levels which can be used to estimate control thresholds. The average loss caused in Hamlin orange fruits by C. capitata was 2.5 tons per hectare or 7.5% of production.Esta pesquisa teve como objetivos: avaliar o efeito do pH inicial, 4.5; 6.5 e 8.5, do atrativo proteico MilhocinaÂź e bĂłrax (tetraborato de sĂłdio) na captura de moscas-das-frutas em armadilhas McPhail; estudar densidades de armadilhas, 1; 2; 4 e 8 por hectare, para estimar nĂ­veis de controle em laranja cv. Hamlin, na regiĂŁo central de SĂŁo Paulo. A espĂ©cie predominante, com 99% das moscas-das-frutas capturadas, foi Ceratitis capitata, sendo 80% de fĂȘmeas. As maiores capturas de C. capitata ocorreram nas armadilhas com MilhocinaÂź e bĂłrax em pH 8.5. As capturas, nas 4 densidades, foram semelhantes, indicando que a população pode ser estimada com uma armadilha por hectare em ĂĄreas de altas populaçÔes. Houve relaçÔes positivas entre capturas de C. capitata e o nĂșmero de frutos danificados, 2 e 3 semanas apĂłs a captura. Assim, foram obtidas equaçÔes que relacionam a captura e o dano, possibilitando estimar nĂ­veis de controle desse inseto. As perdas mĂ©dias causadas por C. capitata em laranja cv. Hamlin chegaram a 2,5 toneladas de frutos por hectare ou 7,5% da produção.info:eu-repo/semantics/publishedVersio

    The UK market for energy service contracts in 2014–2015

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    This paper provides an overview of the UK market for energy service contracts in 2014 and highlights the growing role of intermediaries. Using information from secondary literature and interviews, it identifies the businesses offering energy service contracts, the sectors and organisations that are purchasing those contracts, the types of contract that are available, the areas of market growth and the reasons for that growth. The paper finds that the UK market is relatively large, highly diverse, concentrated in particular sectors and types of site and overwhelmingly focused upon established technologies with high rates of return. A major driver is the emergence of procurement frameworks for energy service contracts in the public sector. These act as intermediaries between clients and contractors, thereby lowering transaction costs and facilitating learning. The market is struggling to become established in commercial offices, largely as a result of split incentives, and is unlikely to develop further in this sector without different business models, tenancy arrangements and policy initiatives. Overall, the paper concludes that energy service contracts can play an important role in the transition to a low-carbon economy, especially when supported by intermediaries, but their potential is still limited by high transaction costs

    The most creative organization in the world? The BBC, 'creativity' and managerial style

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    The managerial styles of two BBC directors-general, John Birt and Greg Dyke, have often been contrasted but not so far analysed from the perspective of their different views of 'creative management'. This article first addresses the orthodox reading of 'Birtism'; second, it locates Dyke's 'creative' turn in the wider context of fashionable neo-management theory and UK government creative industries policy; third, it details Dyke's drive to change the BBC's culture; and finally, it concludes with some reflections on the uncertainties inherent in managing a creative organisation

    Affordances, constraints and information flows as ‘leverage points’ in design for sustainable behaviour

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    Copyright @ 2012 Social Science Electronic PublishingTwo of Donella Meadows' 'leverage points' for intervening in systems (1999) seem particularly pertinent to design for sustainable behaviour, in the sense that designers may have the scope to implement them in (re-)designing everyday products and services. The 'rules of the system' -- interpreted here to refer to affordances and constraints -- and the structure of information flows both offer a range of opportunities for design interventions to in fluence behaviour change, and in this paper, some of the implications and possibilities are discussed with reference to parallel concepts from within design, HCI and relevant areas of psychology
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