2,032 research outputs found

    Phylogenetic Analysis of the Zingiberales Based on \u3cem\u3erbc\u3c/em\u3eL Sequences

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    Morphological data have been used previously to construct phylogenies of the eight families of the Zingiberales one of the most widely accepted monophyletic groups of flowering plants. To provide additional support for phylogenetic relationships within the order, and placement of the order among monocots, we present a parsimony analysis of DNA sequences from the chloroplast-encoded gene, rbcL, for 21 species of Zingiberales and proposed relatives. Five analyses with equal, and differential weights were performed. All analyses resulted in the same most parsimonious tree for taxa within the Zingiberales and the immediate outgroup. The closest sister group to the Zingiberales based on these data is a clade containing Commelinaceae/Haemodoraceae/Pontederiacea. The tree topology within the order based on rbcL sequence data is different from previous morphological analyses. The order can be divided into two sister groups, one containing the Costaceae and Marantaceae, and the other, the remaining six families. All recognized families are monophyletic with the exception of the Musaceae, which is paraphyletic with the Cannaceae. Wtih trees one and two steps longer tha the most parsimonious trees, phylogenetic resolution is rapidly lost, suggesting that the phylogenetic utility of rbcL sequence date for the Zingiberales is limited to interordinal and intrafamilial relationships

    Phylogenetic Hypotheses for the Monocotyledons Constructed from rbcL Sequence Data

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    DNA sequences for the plastid locus that encodes the large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase (rbcL) were determined for 18 species of monocotyledons in 15 families. These data were analyzed together with sequences for 60 other monocot species in a total of 52 families by the maximum likelihood method producing one, presumably optimal, topology. An additional 26 species were added (104 total monocot species) and analyzed by the parsimony method with an outgroup of 18 dicot species producing 109 trees of 3,932 steps. The rbcL data show at least moderate support for seven lineages corresponding to the following orders, superorders, or combinations: Arecanae; Asparagales (excluding Hypoxidaceae) plus Iridaceae; Cyclanthanae plus Pandananae; Dioscoreales; Orchidales; Typhales; and Zingiberanae. Six clades corresponding to families or genera are well supported, including: Agavaceae, Asphodelaceae, Bromeliaceae, Hypoxidaceae, Poaceae, and Tradescantia. The two, earliest diverging multispecies clades in our rbcL phylogenies, Alismatanae and Aranae, are only weakly supported, and Bromelianae, Commelinanae, and Lilianae are paraphyletic. In all analyses Acorus calamus is phylogenetically isolated as the sister species to the remaining species of monocotyledons

    Measurement of associated Z plus charm production in proton-proton collisions at root s=8TeV

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    A study of the associated production of a Z boson and a charm quark jet (Z + c), and a comparison to production with a b quark jet (Z + b), in pp collisions at a centre-of-mass energy of 8 TeV are presented. The analysis uses a data sample corresponding to an integrated luminosity of 19.7 fb(-1), collected with the CMS detector at the CERN LHC. The Z boson candidates are identified through their decays into pairs of electrons or muons. Jets originating from heavy flavour quarks are identified using semileptonic decays of c or b flavoured hadrons and hadronic decays of charm hadrons. The measurements are performed in the kinematic region with two leptons with pT(l) > 20 GeV, vertical bar eta(l)vertical bar 25 GeV and vertical bar eta(jet)vertical bar Z + c + X) B(Z -> l(+)l(-)) = 8.8 +/- 0.5 (stat)+/- 0.6 (syst) pb. The ratio of the Z+c and Z+b production cross sections is measured to be sigma(pp -> Z+c+X)/sigma (pp -> Z+b+X) = 2.0 +/- 0.2 (stat)+/- 0.2 (syst). The Z+c production cross section and the cross section ratio are also measured as a function of the transverse momentum of theZ boson and of the heavy flavour jet. The measurements are compared with theoretical predictions.Peer reviewe

    Measurement of the underlying event activity in inclusive Z boson production in proton-proton collisions at root s=13 TeV

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    This paper presents a measurement of the underlying event activity in proton-proton collisions at a center-of-mass energy of 13TeV, performed using inclusive Z boson production events collected with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 2.1 fb(-1). The underlying event activity is quantified in terms of the charged particle multiplicity, as well as of the scalar sum of the charged particles' transverse momenta in different topological regions defined with respect to the Z boson direction. The distributions are unfolded to the stable particle level and compared with predictions from various Monte Carlo event generators, as well as with similar CDF and CMS measurements at center-of-mass energies of 1.96 and 7TeV respectively.Peer reviewe

    The heterogeneity of family: Responses to representational invisibility by LGBTQ parents

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    This article draws on qualitative research data collected in semi-structured interviews conducted during 2013 and 2014 with 30 lesbian, gay, bisexual, trans, and queer (LGBTQ) parents living in England and Scotland. It explores how LGBTQ parents respond to media representations of families like theirs, and build narratives of family identity from limited cultural resources. Media, encompassing a range of cultural representational resources, including advertisements, television, books and films, produces specific knowledges about LGBTQ families. Participants argued that popular entertainment media (including Modern Family) offered a limited range of representations of LGBTQ parents and concretizes knowledge about the shape of families. I argue that available representations fail to acknowledge the diversity of non-heterosexual family forms and that this representational gap results in socio-cultural invisibility. I explore the responses LGBTQ parents had to such gaps and how they negotiated, or rejected representational meanings in order to consolidate new narratives of family

    Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV

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    Many measurements and searches for physics beyond the standard model at the LHC rely on the efficient identification of heavy-flavour jets, i.e. jets originating from bottom or charm quarks. In this paper, the discriminating variables and the algorithms used for heavy-flavour jet identification during the first years of operation of the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, are presented. Heavy-flavour jet identification algorithms have been improved compared to those used previously at centre-of-mass energies of 7 and 8 TeV. For jets with transverse momenta in the range expected in simulated tt\mathrm{t}\overline{\mathrm{t}} events, these new developments result in an efficiency of 68% for the correct identification of a b jet for a probability of 1% of misidentifying a light-flavour jet. The improvement in relative efficiency at this misidentification probability is about 15%, compared to previous CMS algorithms. In addition, for the first time algorithms have been developed to identify jets containing two b hadrons in Lorentz-boosted event topologies, as well as to tag c jets. The large data sample recorded in 2016 at a centre-of-mass energy of 13 TeV has also allowed the development of new methods to measure the efficiency and misidentification probability of heavy-flavour jet identification algorithms. The heavy-flavour jet identification efficiency is measured with a precision of a few per cent at moderate jet transverse momenta (between 30 and 300 GeV) and about 5% at the highest jet transverse momenta (between 500 and 1000 GeV)

    Evidence for the Higgs boson decay to a bottom quark–antiquark pair

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