7,633 research outputs found

    Murder in the Cathedral

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    Elliot\u27s play about the murder of Thomas a Becket was performed at John Carroll University in February of 1937.https://collected.jcu.edu/plays/1113/thumbnail.jp

    Double Charge Exchange And Configuration Mixing

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    The energy dependence of forward pion double charge exchange reactions on light nuclei is studied for both the Ground State transition and the Double-Isobaric-Analog-State transitions. A common characteristic of these double reactions is a resonance-like peak around 50 MeV pion lab energy. This peak arises naturally in a two-step process in the conventional pion-nucleon system with proper handling of nuclear structure and pion distortion. A comparison among the results of different nuclear structure models demonstrates the effects of configuration mixing. The angular distribution is used to fix the single particle wave function.Comment: Added 1 figure (now 8) corrected references and various other change

    East Coker

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    Status of Neutrino Masses and Mixing and Future Perspectives

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    Status of the problem of neutrino masses, mixing and oscillations is discussed. Future perspectives are briefly considered.Comment: Report at the conference IRGAC 2006, Barcelona July 11-15 200

    Commensurate and modulated magnetic phases in orthorhombic A1C60

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    Competing magnetically ordered structures in polymerized orthorhombic A1C60 are studied. A mean-field theory for the equilibrium phases is developed using an Ising model and a classical Heisenberg model to describe the competition between inter- and intra-chain magnetic order in the solid. In the Ising model, the limiting commensurate one-dimensional and three-dimensional phases are separated by a commensurate three-sublattice state and by two sectors containing higher-order commensurate phases. For the Heisenberg model the quasi-1D phase is never the equilibrium state; instead the 3D commensurate phases exhibits a transition to a continuum of coplanar spiral magnetic phases.Comment: 11 pages REVTeX 3.0 plus 4 figures appende

    Modification of the surface band-bending of a silicon CCD for low-energy electron detection

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    Silicon CCDs have limited sensitivity to particles and photons with short penetration depth, due to the surface depletion caused by the inherent positive charge in the native oxide. Because of surface depletion, internally-generated electrons are trapped near the irradiated surface and therefore cannot be transported to the detection circuitry. This deleterious surface potential can be eliminated by low-temperature molecular beam epitaxial (MBE) growth of a delta-doped layer on the Si surface. This effect has been demonstrated through achievement of 100% internal quantum efficiency for UV photons detected with delta-doped CCDs. In this paper, we will discuss the modification of the band bending near the CCD surface by low-temperature MBE and report the application of delta-doped CCDs to low-energy electron detection. We show that modification of the surface can greatly improve sensitivity to low-energy electrons. Measurements comparing the response of delta-doped CCDs with untreated CCDs were made in the 50 eV-1.5 keV energy range. For electrons with energies below 300 eV, the signal from untreated CCDs was below the detection limit for our apparatus, and data are presented only for the response of delta-doped CCDs at these energies. The effects of multiple electron hole pair (EHP) production and backscattering on the observed signals are discussed

    Density waves theory of the capsid structure of small icosahedral viruses

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    We apply Landau theory of crystallization to explain and to classify the capsid structures of small viruses with spherical topology and icosahedral symmetry. We develop an explicit method which predicts the positions of centers of mass for the proteins constituting viral capsid shell. Corresponding density distribution function which generates the positions has universal form without any fitting parameter. The theory describes in a uniform way both the structures satisfying the well-known Caspar and Klug geometrical model for capsid construction and those violating it. The quasiequivalence of protein environments in viral capsid and peculiarities of the assembly thermodynamics are also discussed.Comment: 8 pages, 3 figur

    Nucleosynthesis in the Early Galaxy

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    Recent observations of r-process-enriched metal-poor star abundances reveal a non-uniform abundance pattern for elements Z≀47Z\leq47. Based on non-correlation trends between elemental abundances as a function of Eu-richness in a large sample of metal-poor stars, it is shown that the mixing of a consistent and robust light element primary process (LEPP) and the r-process pattern found in r-II metal-poor stars explains such apparent non-uniformity. Furthermore, we derive the abundance pattern of the LEPP from observation and show that it is consistent with a missing component in the solar abundances when using a recent s-process model. As the astrophysical site of the LEPP is not known, we explore the possibility of a neutron capture process within a site-independent approach. It is suggested that scenarios with neutron densities nn≀1013n_{n}\leq10^{13} cm−3cm^{-3} or in the range nn≄1024n_{n}\geq10^{24} cm−3cm^{-3} best explain the observations.Comment: 28 pages, 7 Postscript figures. To be published in The Astrophysical Journa

    Isopoll Maps and an Analysis of the Distribution of the Modern Pollen Rain, Eastern and Central Northern Canada

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    At 39 sites in eastern and central northern Canada, multiple samples of surface moss and lichens have been analyzed for their pollen content. Although pollen from 20 to 30 taxa were identified in the samples from each site, 8 pollen types (Alnus, Betula, Picea. Pinus, Salix, Gramineae, Cyperaceae and Ericaceae) usually comprise 90 to 100% of the pollen rain. We present isopoll maps of these taxa based on mean percentages of multiple samples from the 39 sites. The data are further analyzed by a number of statistical methods to determine whether there are specific pollen assemblages within this region and to what extent present day climatic parameters and floristic/vegetation zones correlate with pollen counts. Cluster analysis on raw data and on principal component scores yields six distinct pollen assemblages which are further examined by discriminant analysis. Pollen concentration maps for eastern Canada are also presented here and used as an aid in interpreting the percentage data.L'analyse pollinique d'un grand nombre d'Ă©chantillons de mousses et de lichens prĂ©levĂ©s Ă  la surface de 39 sites du centre et de l'est du Nord canadien a Ă©tĂ© faite. MĂȘme si on a pu identifier de 20 Ă  30 taxons dans les Ă©chantillons provenant de chacun des sites, 8 types polliniques (Alnus, Betula, Picea, Pinus, Salix, Gramineae, Cyperaceae, Ericaceae) se partagent habituellement entre 90 et 100% de la pluie pollinique. On prĂ©sente ici les cartes isopolles de ces taxons, basĂ©es sur les pourcentages moyens des nombreux Ă©chantillons prĂ©levĂ©s sur les 39 sites. L'analyse statistique des donnĂ©es qui a Ă©tĂ© faite avait pour but de dĂ©gager des assemblages polliniques distincts et de dĂ©terminer si les paramĂštres climatiques actuels ainsi que les rĂ©gions floristiques pouvaient ĂȘtre mis en corrĂ©lation avec les sommes polliniques. Une analyse de grappes et de scores des composantes principales et des donnĂ©es brutes a permis de dĂ©gager 6 assemblages polliniques distincts qui ont fait l'objet d'une analyse discriminante. Les cartes de concentration pollinique de l'est du Canada, qui ont Ă©tĂ© dressĂ©es, ont servi Ă  l'interprĂ©tation des donnĂ©es en pourcentage

    Population genetics of Glossina morsitans submorsitans (Diptera: Glossinidae)

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    Breeding structure of Glossina morsitans submorsitans Newstead was evaluated by using genetic markers in mitochondrial DNA where diversity was scored at two loci in five natural populations from The Gambia and two populations in Ethiopia (form ugandensis Vanderplank), countries separated by c. 5450 km. Twenty six haplotype combinations were found, of which 17 were shared among two or more populations. Nine haplotypes were found in The Gambia and 23 haplotypes in Ethiopia. There were 12 unique haplotypes. Only six haplotypes were shared between the two countries. Populations in The Gambia (he = 0.26 ± 0.04) showed less than a third of the diversity of populations in Ethiopia (he= 0.84 ± 0.03). This suggests recovery from an earlier reduction in population. In a nested analysis of molecular variance of haplotype frequencies, 65%of the variance was due to differences within populations, 34% to differences between populations grouped by country, and only 1% was due to differences among populations within countries. In terms of gene flow, the fixation index FST= 0.35, which leads to an estimate by Wright’s island model of less than one reproducing migrant per generation exchanged between the eastern and western submorsitanspopulations. Nei’s genetic similarity measure showed a deep division between Gambian and Ethiopian populations
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