12,924 research outputs found

    Traumatic hyphaema following successive vacuum and forceps-assisted delivery

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    Hyphaema can cause corneal staining and is a potential risk for glaucoma. We report a case of a neonate with isolated traumatic hyphaema following a prolonged delivery with the consecutive use of vacuum and forceps. A review the literature discusses reports of ophthalmic injuries associated with assisted vaginal deliveries.peer-reviewe

    Tunable Double Negative Band Structure from Non-Magnetic Coated Rods

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    A system of periodic poly-disperse coated nano-rods is considered. Both the coated nano-rods and host material are non-magnetic. The exterior nano-coating has a frequency dependent dielectric constant and the rod has a high dielectric constant. A negative effective magnetic permeability is generated near the Mie resonances of the rods while the coating generates a negative permittivity through a field resonance controlled by the plasma frequency of the coating and the geometry of the crystal. The explicit band structure for the system is calculated in the sub-wavelength limit. Tunable pass bands exhibiting negative group velocity are generated and correspond to simultaneously negative effective dielectric permittivity and magnetic permeability. These can be explicitly controlled by adjusting the distance between rods, the coating thickness, and rod diameters

    High rate locally-correctable and locally-testable codes with sub-polynomial query complexity

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    In this work, we construct the first locally-correctable codes (LCCs), and locally-testable codes (LTCs) with constant rate, constant relative distance, and sub-polynomial query complexity. Specifically, we show that there exist binary LCCs and LTCs with block length nn, constant rate (which can even be taken arbitrarily close to 1), constant relative distance, and query complexity exp(O~(logn))\exp(\tilde{O}(\sqrt{\log n})). Previously such codes were known to exist only with Ω(nβ)\Omega(n^{\beta}) query complexity (for constant β>0\beta > 0), and there were several, quite different, constructions known. Our codes are based on a general distance-amplification method of Alon and Luby~\cite{AL96_codes}. We show that this method interacts well with local correctors and testers, and obtain our main results by applying it to suitably constructed LCCs and LTCs in the non-standard regime of \emph{sub-constant relative distance}. Along the way, we also construct LCCs and LTCs over large alphabets, with the same query complexity exp(O~(logn))\exp(\tilde{O}(\sqrt{\log n})), which additionally have the property of approaching the Singleton bound: they have almost the best-possible relationship between their rate and distance. This has the surprising consequence that asking for a large alphabet error-correcting code to further be an LCC or LTC with exp(O~(logn))\exp(\tilde{O}(\sqrt{\log n})) query complexity does not require any sacrifice in terms of rate and distance! Such a result was previously not known for any o(n)o(n) query complexity. Our results on LCCs also immediately give locally-decodable codes (LDCs) with the same parameters

    Heuristic algorithms for the min-max edge 2-coloring problem

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    In multi-channel Wireless Mesh Networks (WMN), each node is able to use multiple non-overlapping frequency channels. Raniwala et al. (MC2R 2004, INFOCOM 2005) propose and study several such architectures in which a computer can have multiple network interface cards. These architectures are modeled as a graph problem named \emph{maximum edge qq-coloring} and studied in several papers by Feng et. al (TAMC 2007), Adamaszek and Popa (ISAAC 2010, JDA 2016). Later on Larjomaa and Popa (IWOCA 2014, JGAA 2015) define and study an alternative variant, named the \emph{min-max edge qq-coloring}. The above mentioned graph problems, namely the maximum edge qq-coloring and the min-max edge qq-coloring are studied mainly from the theoretical perspective. In this paper, we study the min-max edge 2-coloring problem from a practical perspective. More precisely, we introduce, implement and test four heuristic approximation algorithms for the min-max edge 22-coloring problem. These algorithms are based on a \emph{Breadth First Search} (BFS)-based heuristic and on \emph{local search} methods like basic \emph{hill climbing}, \emph{simulated annealing} and \emph{tabu search} techniques, respectively. Although several algorithms for particular graph classes were proposed by Larjomaa and Popa (e.g., trees, planar graphs, cliques, bi-cliques, hypergraphs), we design the first algorithms for general graphs. We study and compare the running data for all algorithms on Unit Disk Graphs, as well as some graphs from the DIMACS vertex coloring benchmark dataset.Comment: This is a post-peer-review, pre-copyedit version of an article published in International Computing and Combinatorics Conference (COCOON'18). The final authenticated version is available online at: http://www.doi.org/10.1007/978-3-319-94776-1_5

    Growth responses of microalgae, Chlorella salina and Isochrysis galbana exposed to extracts of the macroalga, Hypnea musciformis

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    The influence of methanol extract and its fractions of the marine macroalga, Hypnea musciformis on aquaculturally important microalgae viz., Chlorella salina and Isochrysis galbana were investigated. Lower concentrations of the extract of H. musciformis resulted in marginal growth gain for C. salina and I. galbana. However, the fractionated extract inhibited the growth of both microalgae tested, suggesting toxicity. Results signify the importance of macroalgal extract in regulating the growth of aquaculturally important microalga

    New All-Weather Fishery Harbour For Veraval

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    Veraval forms one of the major fish landing centres of the Saurashtra coast. The all-weather fishery harbour plan was approved and the World Bank sanctioned Rs. 342 milhon for constructing one each at Veraval and Mangrol. In Veraval the execution of the project was initiated in the year 1977-'78 by the Fisheries Terminus Division(FTD) of the Department of Fisheries

    Nuclear-spin relaxation of 207^{207}Pb in ferroelectric powders

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    Motivated by a recent proposal by O. P. Sushkov and co-workers to search for a P,T-violating Schiff moment of the 207^{207}Pb nucleus in a ferroelectric solid, we have carried out a high-field nuclear magnetic resonance study of the longitudinal and transverse spin relaxation of the lead nuclei from room temperature down to 10 K for powder samples of lead titanate (PT), lead zirconium titanate (PZT), and a PT monocrystal. For all powder samples and independently of temperature, transverse relaxation times were found to be T21.5T_2\approx 1.5 ms, while the longitudinal relaxation times exhibited a temperature dependence, with T1T_1 of over an hour at the lowest temperatures, decreasing to T17T_1\approx 7 s at room temperature. At high temperatures, the observed behavior is consistent with a two-phonon Raman process, while in the low temperature limit, the relaxation appears to be dominated by a single-phonon (direct) process involving magnetic impurities. This is the first study of temperature-dependent nuclear-spin relaxation in PT and PZT ferroelectrics at such low temperatures. We discuss the implications of the results for the Schiff-moment search.Comment: 6 pages, 4 figure
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