5,146 research outputs found

    Circular 73

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    An assessment of Growth of Infrastructure Booms have been a common element in the development of frontier areas in the 19th and 20th centuries. Most commonly, the booms have been associated with resource development such as the mineral booms of the western United States. Booms usually involve some type of dramatic short- term change which has wide-ranging implications (Gilmore, 1976). Since the arrival of the Russians in Alaska, six major booms have occurred: furs, whales, salmon, minerals, military, and petroleum. Each of these booms has, to some degree, created changes in the landscape of Alaska, in particular, the infrastructural base, which in turn has facilitated subsequent development, either another major boom, or a smaller development. For example, agricultural development has been enhanced by mineral, military, and petroleum booms in Alaska. The cumulative impact on infrastructure of more than one boom, or multibooms, as it is referred to here, is the focus of this paper. One problem encountered in studying booms is that there is no general agreement on what constitutes a boom. Detailed studies of booms in communities such as Dixon’s (1978) analysis of Fairbanks and Gilmore’s multi-community work in the Great Plains—Rocky •mountain regions, contained no specific definition of the term “boom”. Yet it was clear in each study that something dramatic had occurred. More general historical studies of the Western mineral bonanzas (Greever, 1963) or the Klondike gold rush (Berton, 1958) likewise suggest a number of factors such as population rise, influx of money, resource extraction, and infrastructure expansion. But in each case, there is no specific factor or define rate of something that specifically qualifies a time period as a boom. In this study, we are concerned with dramatic change of events which have had a major impact on the geographic landscape of an area, As a framework for the initial study, we review those events which have been given attention as boom-type activities in the historical literature of Alaska (Rogers, 1962; Naske and Slotnick, 1987)

    Central Limit Theorems for some Set Partition Statistics

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    We prove the conjectured limiting normality for the number of crossings of a uniformly chosen set partition of [n] = {1,2,...,n}. The arguments use a novel stochastic representation and are also used to prove central limit theorems for the dimension index and the number of levels

    Tests of Transfer Reaction Determinations of Astrophysical S-Factors

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    The 16O(3He,d)17F{}^{16}O ({}^{3}He,d) {}^{17}F reaction has been used to determine asymptotic normalization coefficients for transitions to the ground and first excited states of 17F{}^{17}F. The coefficients provide the normalization for the tails of the overlap functions for 17F16O+p{}^{17}F \to{}^{16}O + p and allow us to calculate the S-factors for 16O(p,γ)17F{}^{16}O (p,\gamma){}^{17}F at astrophysical energies. The calculated S-factors are compared to measurements and found to be in very good agreement. This provides the first test of this indirect method to determine astrophysical direct capture rates using transfer reactions. In addition, our results yield S(0) for capture to the ground and first excited states in 17F^{17}F, without the uncertainty associated with extrapolation from higher energies.Comment: 6 pages, 2 figure

    Asymptotic Normalization Coefficients for 13C+p->14N

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    The 13C(14N,13C)14N^{13}C(^{14}N,^{13}C)^{14}N proton exchange reaction has been measured at an incident energy of 162 MeV. Angular distributions were obtained for proton transfer to the ground and low lying excited states in 14N^{14}N. Elastic scattering of 14N^{14}N on 13C^{13}C also was measured out to the rainbow angle region in order to find reliable optical model potentials. Asymptotic normalization coefficients for the system 13C+p14N^{13}C+p\to {}^{14}N have been found for the ground state and the excited states at 2.313, 3.948, 5.106 and 5.834 MeV in 14N^{14}N. These asymptotic normalization coefficients will be used in a determination of the S-factor for 7Be(p,γ)8B^{7}Be(p,\gamma)^{8}B at solar energies from a measurement of the proton transfer reaction 14N(7Be,8B)13C^{14}N(^{7}Be,^{8}B)^{13}C.Comment: 5 pages, 6 figure

    The Development of Jomo Kenyatta International Airport as a Regional Aviation Hub

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    Air transportation plays an important role in the social and economic development of the global system and the countries that seek to participate in it. As Africa seeks to take its place in the global economy, it is increasingly looking to aviation as the primary means of connecting its people and goods with the world. It has been suggested that Africa as a continent needs to move toward a system of hubs to optimize its scarce resources. Jomo Kenyatta International Airport in Nairobi, Kenya, is one of the airports in the eastern region of Africa that is seeking to fill this role. This paper discusses the prospects for success and the challenges that it will need to overcome, including projections through 2020 for the growth in passenger and cargo traffic

    Expanding the parameters of academia

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    This paper draws on qualitative data gathered from two studies funded by the UK Leadership Foundation for Higher Education to examine the expansion of academic identities in higher education. It builds on Whitchurch’s earlier work, which focused primarily on professional staff, to suggest that the emergence of broadly based projects such as widening participation, learning support and community partnership is also impacting on academic identities. Thus, academic as well as professional staff are increasingly likely to work in multi-professional teams across a variety of constituencies, as well as with external partners, and the binary distinction between ‘academic’ and ‘non-academic’ roles and activities is no longer clear-cut. Moreover, there is evidence from the studies of an intentionality about deviations from mainstream academic career routes among respondents who could have gone either way. Consideration is therefore given to factors that influence individuals to work in more project-oriented areas, as well as to variables that affect ways in which these roles and identities develop. Finally, three models of academically oriented project activity are identified, and the implications of an expansion of academic identities are reviewed

    Asymptotic normalization coefficients for 8B->7Be+p from a study of 8Li->7Li+n

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    Asymptotic normalization coefficients (ANCs) for 8Li->7Li+n have been extracted from the neutron transfer reaction 13C(7Li,8Li)12C at 63 MeV. These are related to the ANCs in 8B->7Be+p using charge symmetry. We extract ANCs for 8B that are in very good agreement with those inferred from proton transfer and breakup experiments. We have also separated the contributions from the p_1/2 and p_3/2 components in the transfer. We find the astrophysical factor for the 7Be(p,gamma)8B reaction to be S_17(0)=17.6+/-1.7 eVb. This is the first time that the rate of a direct capture reaction of astrophysical interest has been determined through a measurement of the ANCs in the mirror system.Comment: 5 pages, 3 figures, 2 table

    Collective Modes of Tri-Nuclear Molecules

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    A geometrical model for tri-nuclear molecules is presented. An analytical solution is obtained provided the nuclei, which are taken to be prolately deformed, are connected in line to each other. Furthermore, the tri-nuclear molecule is composed of two heavy and one light cluster, the later sandwiched between the two heavy clusters. A basis is constructed in which Hamiltonians of more general configurations can be diagonalized. In the calculation of the interaction between the clusters higher multipole deformations are taken into account, including the hexadecupole one. A repulsive nuclear core is introduced in the potential in order to insure a quasi-stable configuration of the system. The model is applied to three nuclear molecules, namely 96^{96}Sr + 10^{10}Be + 146^{146}Ba, 108^{108}Mo + 10^{10}Be + 134^{134}Te and 112^{112}Ru + 10^{10}Be + 130^{130}Sn.Comment: 24 pages, 9 figure

    How does breakup influence the total fusion of 6,7^{6,7}Li at the Coulomb barrier?

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    Total (complete + incomplete) fusion excitation functions of 6,7^{6,7}Li on 59^{59}Co and 209^{209}Bi targets around the Coulomb barrier are obtained using a new continuum discretized coupled channel (CDCC) method of calculating fusion. The relative importance of breakup and bound-state structure effects on total fusion is particularly investigated. The effect of breakup on fusion can be observed in the total fusion excitation function. The breakup enhances the total fusion at energies just around the barrier, whereas it hardly affects the total fusion at energies well above the barrier. The difference between the experimental total fusion cross sections for 6,7^{6,7}Li on 59^{59}Co is notably caused by breakup, but this is not the case for the 209^{209}Bi target.Comment: 9 pages, 9 figures, Submitted to Phys. Rev.
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