777 research outputs found

    Standard Model Physics Results from LEP2

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    At LEP2 many Standard Model predictions are tested up to centre-of-mass energies of 209 GeV. Fermion pair production cross sections and asymmetries agree well with the theoretical expectation over the entire energy range. The measurements are used to determine the gamma/Z interference and to search for contact interactions up to 20 TeV. The cross sections for single-W, ZZ and W+W- production agree well with the expectations. The branching fractions of the W boson into hadrons and leptons are determined as well as the CKM matrix element |V_{cs}|. Precise measurements of the W mass and width are presented yielding MW=80.427+-0.046 GeV and GammaW=2.12=_0.11 GeV. All electroweak data are very consistent with the Standard Model predictions. In a combined fit using the recent value of Delta alpha_{had}^(5)(s) the mass of the Higgs boson is constrained to MH=88^{+60}_{-37} GeV.Comment: 16 pages, 6 figures, Presented at the Fifth International Symposium on Radiative Corrections (RADCOR 2000), Carmel, CA, September 11-15, 200

    Listening to Images: Creating Disruptions & Building Community

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    As humans we empathize through stories, and images foster human connectivity and represent understandings of and experiences in place. Teachers can empower students by listening with our eyes and our ears. This talk examines images and foregrounds the use of creative and revision processes that add nuance and build community

    Not only the butterflies: managing ants on road verges to benefit Phengaris (Maculinea) butterflies

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    Obligate myrmecophilic butterfly species, such as Phengaris (Maculinea) teleius and P. nausithous, have narrow habitat requirements. Living as a caterpillar in the nests of the ant species Myrmica scabrinodis and M. rubra, respectively, they can only survive on sites with both host ants and the host plant Great Burnet Sanguisorba officinalis. After having been reintroduced into a nature reserve in the Netherlands in 1990, both butterfly species expanded their distribution to linear landscape elements such as road verges and ditch edges outside this reserve. As additional habitat of both butterfly species, vegetation management of these landscape elements became important. Our results show that a management beneficial for Phengaris butterflies should aim to increase the nest density of Myrmica species, at the same time reducing the density of nests of the competitor Lasius niger or at least keeping them at a low density. Unfavourable grassland management under which L. niger thrives, includes not mowing or flail-cutting the grass, or depositing dredgings along the side of the ditch. Management favourable for the two Myrmica species differs, demanding some flexibility if both species are to benefit. M. scabrinodis is best supported with early mowing of the road verge vegetation or late mowing in the nature reserve, both of which result in an open vegetation and warm microclimate. In contrast, the nest sites of M. rubra should be left undisturbed during the summer, and mown in late autumn. Mowing of butterfly habitat should be avoided between mid-June and mid-September as this would remove the flowerheads of the Sanguisorba plants, on which the butterflies lay their eggs

    Phengaris (Maculinea) teleius butterflies select host plants close to Myrmica ants for oviposition, but P. nausithous do not

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    Many lycaenid butterfly species have interactions with ants, with 12% obligatorily depending on two sequential sources of larval food, namely host plants and host ants. When host plants are abundant but the density of host ant nests is relatively low, most host plants have no host ant nest in their vicinity and are thus unsuitable for larval survival. Obligatorily myrmecophilous female butterflies, whose caterpillars feed on ant larvae, would have a comparative advantage if they deposit eggs on host plants in the proximity of a host ant nest. However, this ant-mediated oviposition has been hotly debated. In an open-air insectory experiment, we tested whether oviposition is ant-mediated or not for two obligatory myrmecophilous butterfly species, Phengaris (Maculinea) nausithous Bergsträsser and Phengaris teleius Bergsträsser (Lepidoptera: Lycaenidae). Female butterflies could select host plants close to either no ant nest or a nest of one of the two Myrmica species (Hymenoptera: Formicidae) that are thought to be their host ant. Our results support ant-mediated oviposition in P. teleius, but also indicate that there is no preference for either of the Myrmica species. More eggs were deposited and more caterpillars were found on long flowerheads close to Myrmica ant nests than on those without nests. Our findings suggest that ant presence is more important than flowerhead phenology for females of P. teleius. In contrast, P. nausithous females were not attracted by ants but preferred long flowerheads with a low percentage of green coloration. With these findings, this study contributes to better understanding of the habitat requirements of two highly specialized butterfly species

    At home on foreign meadows: the reintroduction of two Maculineae butterfly species

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    Maculinea butterflies live as obligate parasites of specific Myrmica host ants in meadow and heathland habitat maintained by low intensity landuse. Changes in agriculture caused the decline and extinction of many populations. In The Netherlands, Maculinea nausithous and M. teleius disappeared in the 1970s. In 1990, they were reintroduced following the recommendations of the IUCN. This study focuses on the evaluation of this reintroduction into the nature reserve Moerputten in the province of Northern Brabant. Population establishment and dispersal were monitored and accompanied by research on the impact of the reintroduction on species-specific genetic composition and behaviour. Maculinea teleius immediately established itself on one meadow, where the population still occurs today. Maculinea nausithous , being the more mobile species, colonized habitat patches with the specific host ant at higher distances. Three subpopulations were founded.At the small spatial scale the females of both species were able to select habitat patches with host plants and host ants to deposit their eggs, rather then loosing many offspring by random oviposition. At the ladscape scale the occurence of the populations was also strongly related to the presence of the specific host ant species. However, through the limited dispersal capacity of the adults high quality patches at greater distance remain uncolonized. Genetic analysis showed that the new populations have not experienced a bottleneck in numbers following the translocation. However, the populations experienced selection due to changed ecological conditions at the founder site, but ecologically relevant traits were apparently not affected.The conservation of the reintroduced population should concentrate on keeping a high habitat quality on the colonized sites and enabling the development of metapopulations by improving the management of potential sites within colonization distance. Ultimately, the persistence of the populations depends on the availability of an extensive network of suitable habitat patches. This requires conservation management at a landscape scale. This study emphasizes that a carefully planned and implemented reintroduction can be a successful tool for species conservation if both small and large spatial scales are taken into account.</p

    Status and perspective of detector databases in the CMS experiment at the LHC

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    This note gives an overview at a high conceptual level of the various databases that capture the information concerning the CMS detector. The detector domain has been split up into four, partly overlapping parts that cover phases in the detector life cycle: construction, integration, configuration and condition, and a geometry part that is common to all phases. The discussion addresses the specific content and usage of each part, and further requirements, dependencies and interfaces

    “Practicing What We Teach in Writing Methods: Crossover Strategies for Preparing Elementary and Secondary English Language Arts Teachers”

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    Panelists shared writing methods assignments (digital documentaries, field journals, collaborative presentations, annotated bibliographies) that featured Graham and Perin’s (2007) 11 elements of effective writing instruction. Participants critiqued the assignments and discuss how pre-service teachers’ understandings of effective elementary and secondary writing instruction are transformed
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