2,818 research outputs found

    Three New Species of Saccocirrus (Polychaeta: Saccocirridae) from Hawai'i

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    Three new species of saccocirrids from interstitial sand habitats off O'ahu, Hawai'i, are described. Two are from subtidal depths, 9-33 m, and the third is from the intertidal to 3.5 m deep on a fringing reef and at Hanauma Bay, the Marine Life Conservation District and public park. The two deeper-water species, Saccocirrus oahuensis, n. sp. and S. waianaensis, n. sp., have 76-119 and 157-210 segments, respectively; they also have bilateral gonads but lack a pharyngeal pad. The third, S. alanhongi, n. sp., has 35-47 segments, unilateral gonads, and a muscular pharyngeal pad. These species are distinguished from 18 known Saccocirrus spp. by their unique chaetation, number of segments, presence or absence of ventral cilia, and pygidial adhesive structures. Saccocirms oahuensis consumes foraminiferans, and S. alanhongi contained diatoms, unicellular algae, and ostracods. These species add to the interstitial fauna of O'ahu and cooccur with polychaetes Nerilla antennata (Nerillidae) and protodrilids (Protodrilidae), and Kinorhyncha. Saccocirrus alanhongi withstands almost daily disturbance by 600-1200 bathers per day entering the sandy swimming holes in the reef at Hanauma Bay

    The genus Boccardia (Polychaeta: Spionidae) associated with mollusc shells on the south coast of South Africa

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    Three species of Boccardia (B. polybranchia, B. pseudonatrix and B. proboscidea) were associated with mollusc shells on the south and south-east coasts of South Africa. Boccardia polybranchia was widely distributed along the coast and falls within the known distribution range of this species. Comparisons with material from other, international, locations showed that some specimens have been misidentified. No characters could be found to characterize distinct species for different regions within the range of B. polybranchia, as currently recognized. Boccardia pseudonatrix was found only at the most eastern site, increasing its known distribution range. Boccardia proboscidea, a non-indigenous species, was found only on abalone farms and was most abundant in the west

    Multijet production in neutral current deep inelastic scattering at HERA and determination of α_{s}

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    Multijet production rates in neutral current deep inelastic scattering have been measured in the range of exchanged boson virtualities 10 5 GeV and –1 < η_{LAB}^{jet} < 2.5. Next-to-leading-order QCD calculations describe the data well. The value of the strong coupling constant α_{s} (M_{z}), determined from the ratio of the trijet to dijet cross sections, is α_{s} (M_{z}) = 0.1179 ± 0.0013 (stat.)_{-0.0046}^{+0.0028}(exp.)_{-0.0046}^{+0.0028}(th.)

    Negative phenotypic and genetic associations between copulation duration and longevity in male seed beetles

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    Reproduction can be costly and is predicted to trade-off against other characters. However, while these trade-offs are well documented for females, there has been less focus on aspects of male reproduction. Furthermore, those studies that have looked at males typically only investigate phenotypic associations, with the underlying genetics often ignored. Here, we report on phenotypic and genetic trade-offs in male reproductive effort in the seed beetle, Callosobruchus maculatus. We find that the duration of a male's first copulation is negatively associated with subsequent male survival, phenotypically and genetically. Our results are consistent with life-history theory and suggest that like females, males trade-off reproductive effort against longevity

    Jet production in charged current deep inelastic eâșp scatteringat HERA

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    The production rates and substructure of jets have been studied in charged current deep inelastic eâșp scattering for QÂČ > 200 GeVÂČ with the ZEUS detector at HERA using an integrated luminosity of 110.5 pb⁻Âč. Inclusive jet cross sections are presented for jets with transverse energies E_{T}^{jet} > 5 GeV. Measurements of the mean subjet multiplicity, 〈n_{sbj}âŒȘ, of the inclusive jet sample are presented. Predictions based on parton-shower Monte Carlo models and next-to-leading-order QCD calculations are compared to the measurements. The value of α_{s} (M_{z}), determined from 〈n_{sbj}âŒȘ at y_{cut} = 10⁻ÂČ for jets with 25 < E_{T}^{jet} < 119 GeV, is α_{s} (M_{z}) = 0.1202 ± 0.0052 (stat.)_{-0.0019}^{+0.0060} (syst.)_{-0.0053}^{+0.0065} (th.). The mean subjet multiplicity as a function of QÂČ is found to be consistent with that measured in NC DIS

    Measurement of inclusive D*+- and associated dijet cross sections in photoproduction at HERA

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    Inclusive photoproduction of D*+- mesons has been measured for photon-proton centre-of-mass energies in the range 130 < W < 280 GeV and a photon virtuality Q^2 < 1 GeV^2. The data sample used corresponds to an integrated luminosity of 37 pb^-1. Total and differential cross sections as functions of the D* transverse momentum and pseudorapidity are presented in restricted kinematical regions and the data are compared with next-to-leading order (NLO) perturbative QCD calculations using the "massive charm" and "massless charm" schemes. The measured cross sections are generally above the NLO calculations, in particular in the forward (proton) direction. The large data sample also allows the study of dijet production associated with charm. A significant resolved as well as a direct photon component contribute to the cross section. Leading order QCD Monte Carlo calculations indicate that the resolved contribution arises from a significant charm component in the photon. A massive charm NLO parton level calculation yields lower cross sections compared to the measured results in a kinematic region where the resolved photon contribution is significant.Comment: 32 pages including 6 figure

    Measurement of Jet Shapes in Photoproduction at HERA

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    The shape of jets produced in quasi-real photon-proton collisions at centre-of-mass energies in the range 134−277134-277 GeV has been measured using the hadronic energy flow. The measurement was done with the ZEUS detector at HERA. Jets are identified using a cone algorithm in the η−ϕ\eta - \phi plane with a cone radius of one unit. Measured jet shapes both in inclusive jet and dijet production with transverse energies ETjet>14E^{jet}_T>14 GeV are presented. The jet shape broadens as the jet pseudorapidity (ηjet\eta^{jet}) increases and narrows as ETjetE^{jet}_T increases. In dijet photoproduction, the jet shapes have been measured separately for samples dominated by resolved and by direct processes. Leading-logarithm parton-shower Monte Carlo calculations of resolved and direct processes describe well the measured jet shapes except for the inclusive production of jets with high ηjet\eta^{jet} and low ETjetE^{jet}_T. The observed broadening of the jet shape as ηjet\eta^{jet} increases is consistent with the predicted increase in the fraction of final state gluon jets.Comment: 29 pages including 9 figure

    Framing Social Justice: The Ties That Bind a Multinational Occupational Community

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    The notion of a frame is central to the conceptualisation of social justice and the grounding of social justice claims. Influential theories of social justice are typically grounded in national or cosmopolitan framings. Those entitled to raise claims of injustice are identified as citizens of states or the globe, respectively. The re-visioning of understandings of space and belonging, incumbent in the processes of globalisation, problematises static geographical framings. We offer an alternative lens and argue for the inclusion of sociological data in accounts of social justice to identify the relevant framing of the community of entitlement. Drawing on secondary analysis of a qualitative dataset, we explore the case of multinational seafarers caught at the intersection of competing appeals to nationality and commonality as an exemplar of transnational workers. And, argue that there are compelling grounds to treat this group of multinational seafarers as a community of entitlement

    Measurement of event shapes in deep inelastic scattering at HERA

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    Inclusive event-shape variables have been measured in the current region of the Breit frame for neutral current deep inelastic ep scattering using an integrated luminosity of 45.0 pb^-1 collected with the ZEUS detector at HERA. The variables studied included thrust, jet broadening and invariant jet mass. The kinematic range covered was 10 < Q^2 < 20,480 GeV^2 and 6.10^-4 < x < 0.6, where Q^2 is the virtuality of the exchanged boson and x is the Bjorken variable. The Q dependence of the shape variables has been used in conjunction with NLO perturbative calculations and the Dokshitzer-Webber non-perturbative corrections (`power corrections') to investigate the validity of this approach.Comment: 7+25 pages, 6 figure
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