254 research outputs found

    The persistence landscape and some of its properties

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    Persistence landscapes map persistence diagrams into a function space, which may often be taken to be a Banach space or even a Hilbert space. In the latter case, it is a feature map and there is an associated kernel. The main advantage of this summary is that it allows one to apply tools from statistics and machine learning. Furthermore, the mapping from persistence diagrams to persistence landscapes is stable and invertible. We introduce a weighted version of the persistence landscape and define a one-parameter family of Poisson-weighted persistence landscape kernels that may be useful for learning. We also demonstrate some additional properties of the persistence landscape. First, the persistence landscape may be viewed as a tropical rational function. Second, in many cases it is possible to exactly reconstruct all of the component persistence diagrams from an average persistence landscape. It follows that the persistence landscape kernel is characteristic for certain generic empirical measures. Finally, the persistence landscape distance may be arbitrarily small compared to the interleaving distance.Comment: 18 pages, to appear in the Proceedings of the 2018 Abel Symposiu

    The Azimuthal Decorrelation of Jets Widely Separated in Rapidity

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    This study reports the first measurement of the azimuthal decorrelation between jets with pseudorapidity separation up to five units. The data were accumulated using the D{\O}detector during the 1992--1993 collider run of the Fermilab Tevatron at s=\sqrt{s}= 1.8 TeV. These results are compared to next--to--leading order (NLO) QCD predictions and to two leading--log approximations (LLA) where the leading--log terms are resummed to all orders in αS\alpha_{\scriptscriptstyle S}. The final state jets as predicted by NLO QCD show less azimuthal decorrelation than the data. The parton showering LLA Monte Carlo {\small HERWIG} describes the data well; an analytical LLA prediction based on BFKL resummation shows more decorrelation than the data.Comment: 6 pages with 4 figures, all uuencoded and gzippe

    Measurement of the WW Boson Mass

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    A measurement of the mass of the WW boson is presented based on a sample of 5982 WeνW \rightarrow e \nu decays observed in ppp\overline{p} collisions at s\sqrt{s} = 1.8~TeV with the D\O\ detector during the 1992--1993 run. From a fit to the transverse mass spectrum, combined with measurements of the ZZ boson mass, the WW boson mass is measured to be MW=80.350±0.140(stat.)±0.165(syst.)±0.160(scale)GeV/c2M_W = 80.350 \pm 0.140 (stat.) \pm 0.165 (syst.) \pm 0.160 (scale) GeV/c^2.Comment: 12 pages, LaTex, style Revtex, including 3 postscript figures (submitted to PRL

    Search for Top Squark Pair Production in the Dielectron Channel

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    This report describes the first search for top squark pair production in the channel stop_1 stopbar_1 -> b bbar chargino_1 chargino_1 -> ee+jets+MEt using 74.9 +- 8.9 pb^-1 of data collected using the D0 detector. A 95% confidence level upper limit on sigma*B is presented. The limit is above the theoretical expectation for sigma*B for this process, but does show the sensitivity of the current D0 data set to a particular topology for new physics.Comment: Five pages, including three figures, submitted to PRD Brief Report

    Second Generation Leptoquark Search in p\bar{p} Collisions at s\sqrt{s} = 1.8 TeV

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    We report on a search for second generation leptoquarks with the D\O\ detector at the Fermilab Tevatron ppˉp\bar{p} collider at s\sqrt{s} = 1.8 TeV. This search is based on 12.7 pb1^{-1} of data. Second generation leptoquarks are assumed to be produced in pairs and to decay into a muon and quark with branching ratio β\beta or to neutrino and quark with branching ratio (1β)(1-\beta). We obtain cross section times branching ratio limits as a function of leptoquark mass and set a lower limit on the leptoquark mass of 111 GeV/c2^{2} for β=1\beta = 1 and 89 GeV/c2^{2} for β=0.5\beta = 0.5 at the 95%\ confidence level.Comment: 18 pages, FERMILAB-PUB-95/185-

    Search for W~1Z~2\widetilde{W}_1\widetilde{Z}_2 Production via Trilepton Final States in ppˉp\bar{p} collisions at s=1.8\sqrt{s}=1.8 TeV

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    We have searched for associated production of the lightest chargino, W~1\widetilde{W}_1, and next-to-lightest neutralino, Z~2\widetilde{Z}_2, of the Minimal Supersymmetric Standard Model in ppˉp\bar{p} collisions at \mbox{s\sqrt{s} = 1.8 TeV} using the \D0 detector at the Fermilab Tevatron collider. Data corresponding to an integrated luminosity of 12.5±0.7\pm 0.7 \ipb were examined for events containing three isolated leptons. No evidence for W~1Z~2\widetilde{W}_1\widetilde{Z}_2 pair production was found. Limits on σ(W~1Z~2)\sigma(\widetilde{W}_1\widetilde{Z}_2)Br(W~1lνZ~1)(\widetilde{W}_1\to l\nu\widetilde{Z}_1)Br(Z~2llˉZ~1)(\widetilde{Z}_2\to l\bar{l}\widetilde{Z}_1) are presented.Comment: 17 pages (13 + 1 page table + 3 pages figures). 3 PostScript figures will follow in a UUEncoded, gzip'd, tar file. Text in LaTex format. Submitted to Physical Review Letters. Replace comments - Had to resumbmit version with EPSF directive

    Jet Production via Strongly-Interacting Color-Singlet Exchange in ppˉp\bar{p} Collisions

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    A study of the particle multiplicity between jets with large rapidity separation has been performed using the D{\O}detector at the Fermilab Tevatron ppˉp\bar{p} Collider operating at s=1.8\sqrt{s}=1.8 TeV. A significant excess of low-multiplicity events is observed above the expectation for color-exchange processes. The measured fractional excess is 1.07±0.10(stat)0.13+0.25(syst)1.07 \pm 0.10({\rm stat})^{+ 0.25}_{- 0.13}({\rm syst})%, which is consistent with a strongly-interacting color-singlet (colorless) exchange process and cannot be explained by electroweak exchange alone. A lower limit of 0.80% (95% C.L.) is obtained on the fraction of dijet events with color-singlet exchange, independent of the rapidity gap survival probability.Comment: 15 pages (REVTeX), 3 PS figs (uuencoded/tar compressed, epsf.sty) Complete postscript available at http://d0sgi0.fnal.gov/d0pubs/journals.html Submitted to Physical Review Letter

    The Plastid Genome of Eutreptiella Provides a Window into the Process of Secondary Endosymbiosis of Plastid in Euglenids

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    Euglenids are a group of protists that comprises species with diverse feeding modes. One distinct and diversified clade of euglenids is photoautotrophic, and its members bear green secondary plastids. In this paper we present the plastid genome of the euglenid Eutreptiella, which we assembled from 454 sequencing of Eutreptiella gDNA. Comparison of this genome and the only other available plastid genomes of photosynthetic euglenid, Euglena gracilis, revealed that they contain a virtually identical set of 57 protein coding genes, 24 genes fewer than the genome of Pyramimonas parkeae, the closest extant algal relative of the euglenid plastid. Searching within the transcriptomes of Euglena and Eutreptiella showed that 6 of the missing genes were transferred to the nucleus of the euglenid host while 18 have been probably lost completely. Euglena and Eutreptiella represent the deepest bifurcation in the photosynthetic clade, and therefore all these gene transfers and losses must have happened before the last common ancestor of all known photosynthetic euglenids. After the split of Euglena and Eutreptiella only one additional gene loss took place. The conservation of gene content in the two lineages of euglenids is in contrast to the variability of gene order and intron counts, which diversified dramatically. Our results show that the early secondary plastid of euglenids was much more susceptible to gene losses and endosymbiotic gene transfers than the established plastid, which is surprisingly resistant to changes in gene content

    Biparental inheritance of plastidial and mitochondrial DNA and hybrid variegation in Pelargonium

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    Plastidial (pt) and mitochondrial (mt) genes usually show maternal inheritance. Non-Mendelian, biparental inheritance of plastids was first described by Baur (Z Indukt Abstamm Vererbungslehre 1:330–351, 1909) for crosses between Pelargonium cultivars. We have analyzed the inheritance of pt and mtDNA by examining the progeny from reciprocal crosses of Pelargoniumzonale and P. inquinans using nucleotide sequence polymorphisms of selected pt and mt genes. Sequence analysis of the progeny revealed biparental inheritance of both pt and mtDNA. Hybrid plants exhibited variegation: our data demonstrate that the inquinans chloroplasts, but not the zonale chloroplasts bleach out, presumably due to incompatibility of the former with the hybrid nuclear genome. Different distribution of maternal and paternal sequences could be observed in different sectors of the same leaf, in different leaves of the same plant, and in different plants indicating random segregation and sorting-out of maternal and paternal plastids and mitochondria in the hybrids. The substantial transmission of both maternal and paternal mitochondria to the progeny turns Pelargonium into a particular interesting subject for studies on the inheritance, segregation and recombination of mt genes

    Rapid Evolution of Enormous, Multichromosomal Genomes in Flowering Plant Mitochondria with Exceptionally High Mutation Rates

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    A pair of species within the genus Silene have evolved the largest known mitochondrial genomes, coinciding with extreme changes in mutation rate, recombination activity, and genome structure
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