174 research outputs found

    Measuring the world city network: new results and developments

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    Balancing London? A preliminary investigation of the “Core Cities” and “Northern Way” spatial policy initiatives using multi-city corporate and commercial law firms

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    This paper reports a preliminary investigation into the economic efficacy of two spatial frameworks – English Core Cities and the Northern Way – recently promoted by national policy makers. We ask whether they are consistent with contemporary economic process in the UK space economy through analyses of commercial multi-city law firms. The latter are treated as an ‘indicator sector’ to define the contemporary UK space economy as practised by law firms. Within this new space of flows, the location strategies of the law firms do confirm the salience of the Northern Way (as trans-Pennine corridor) and Core Cities as part of a larger UK metropolitan space of flows. Conflating the two spatial frameworks leads us to identify hints of a rebalancing of London within a metropolitan UK space. A Manchester polycentric mega-city region is found to be the likely candidate for this role. This finding in no way impinges on London’s dominant global role and we conclude that perhaps mutuality between London and provincial cities is beginning to replace past negative dependency relations

    alpha-nucleus potentials for the neutron-deficient p nuclei

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    alpha-nucleus potentials are one important ingredient for the understanding of the nucleosynthesis of heavy neutron-deficient p nuclei in the astrophysical gamma-process where these p nuclei are produced by a series of (gamma,n), (gamma,p), and (gamma,alpha) reactions. I present an improved alpha-nucleus potential at the astrophysically relevant sub-Coulomb energies which is derived from the analysis of alpha decay data and from a previously established systematic behavior of double-folding potentials.Comment: 6 pages, 3 figures, accepted for publication in Phys. Rev.

    Astrophysical Reaction Rates for 10^{10}B(p,α\alpha)7^{7}Be and 11^{11}B(p,α\alpha)8^{8}Be From a Direct Model

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    The reactions 10^{10}B(p,α\alpha)7^{7}Be and 11^{11}B(p,α\alpha)8^{8}Be are studied at thermonuclear energies using DWBA calculations. For both reactions, transitions to the ground states and first excited states are investigated. In the case of 10^{10}B(p,α\alpha)7^{7}Be, a resonance at ERes=10E_{Res}=10 keV can be consistently described in the potential model, thereby allowing the extension of the astrophysical SS-factor data to very low energies. Strong interference with a resonance at about ERes=550E_{Res}=550 keV require a Breit-Wigner description of that resonance and the introduction of an interference term for the reaction 10^{10}B(p,α1\alpha_1)7^{7}Be^*. Two isospin T=1T=1 resonances (at ERes1=149E_{Res1}=149 keV and ERes2=619E_{Res2}=619 keV) observed in the 11^{11}B+p reactions necessitate Breit-Wigner resonance and interference terms to fit the data of the 11^{11}B(p,α\alpha)8^{8}Be reaction. SS-factors and thermonuclear reaction rates are given for each reaction. The present calculation is the first consistent parametrization for the transition to the ground states and first excited states at low energies.Comment: 27 pages, 5 Postscript figures, uses RevTex and aps.sty; preprint also available at http://quasar.physik.unibas.ch/ Phys. Rev. C, in pres

    Coexistence of 'alpha+ 208Pb' cluster structures and single-particle excitations in 212Po

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    Excited states in 212Po have been populated by alpha transfer using the 208Pb(18O,14C) reaction at 85MeV beam energy and studied with the EUROBALL IV gamma multidetector array. The level scheme has been extended up to ~ 3.2 MeV excitation energy from the triple gamma coincidence data. Spin and parity values of most of the observed states have been assigned from the gamma angular distributions and gamma -gamma angular correlations. Several gamma lines with E(gamma) < 1 MeV have been found to be shifted by the Doppler effect, allowing for the measurements of the associated lifetimes by the DSAM method. The values, found in the range [0.1-0.6] ps, lead to very enhanced E1 transitions. All the emitting states, which have non-natural parity values, are discussed in terms of alpha-208Pb structure. They are in the same excitation-energy range as the states issued from shell-model configurations.Comment: 21 pages, 19 figures, corrected typos, revised arguments in Sect. III

    MHCII-mediated dialog between group 2 innate lymphoid cells and CD4+ T cells potentiates type 2 immunity and promotes parasitic helminth expulsion

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    Group 2 innate lymphoid cells (ILC2s) release interleukin-13 (IL-13) during protective immunity to helminth infection and detrimentally during allergy and asthma. Using two mouse models to deplete ILC2s in vivo, we demonstrate that T helper 2 (Th2) cell responses are impaired in the absence of ILC2s. We show that MHCII-expressing ILC2s interact with antigen-specific T cells to instigate a dialog in which IL-2 production from T cells promotes ILC2 proliferation and IL-13 production. Deletion of MHCII renders IL-13-expressing ILC2s incapable of efficiently inducing Nippostrongylus brasiliensis expulsion. Thus, during transition to adaptive T cell-mediated immunity, the ILC2 and T cell crosstalk contributes to their mutual maintenance, expansion and cytokine production. This interaction appears to augment dendritic-cell-induced T cell activation and identifies a previously unappreciated pathway in the regulation of type-2 immunity

    Study of ^194 Ir via thermal neutron capture and (d,p) reactions

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    Levels of ^194 Ir were studied using thermal neutron capture reaction. A pair spectrometer was used to measure the high-energy gamma-ray spectrum from thermal-neutron capture in enriched ^193 Ir target over the energy range 4640 - 6100 keV. The low-energy gamma-radiation from the reaction was studied with crystal diffraction spectrometers, and conversion electrons were observed with magnetic spectrometers. The high-sensitivity measurements at the Grenoble reactor, evaluated for transition energies up to 500 keV, are compared with lower-sensitivity measurements at the Wuerenlingen and Salaspils reactors. The comparison helped to obtain reliable isotopic identification for a number of ^194 Ir lines. The multipolarity admixtures for 29 gamma-transitions were determined on the basis of conversion lines from different electron subshells. Prompt and delayed gamma-gamma coincidences were measured using semiconductor and scintillation detectors. The ^193 Ir(d,p) high-resolution spectra, observed with a magnetic spectrometer, are given. All these data contributed to establishing a detailed level scheme of ^194 Ir. Additional data and the interpretation of the results in terms of current models will be presented in a forthcoming paper

    G9a regulates group 2 innate lymphoid cell development by repressing the group 3 innate lymphoid cell program.

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    Innate lymphoid cells (ILCs) are emerging as important regulators of homeostatic and disease-associated immune processes. Despite recent advances in defining the molecular pathways that control development and function of ILCs, the epigenetic mechanisms that regulate ILC biology are unknown. Here, we identify a role for the lysine methyltransferase G9a in regulating ILC2 development and function. Mice with a hematopoietic cell-specific deletion of G9a (Vav.G9a(-/-) mice) have a severe reduction in ILC2s in peripheral sites, associated with impaired development of immature ILC2s in the bone marrow. Accordingly, Vav.G9a(-/-) mice are resistant to the development of allergic lung inflammation. G9a-dependent dimethylation of histone 3 lysine 9 (H3K9me2) is a repressive histone mark that is associated with gene silencing. Genome-wide expression analysis demonstrated that the absence of G9a led to increased expression of ILC3-associated genes in developing ILC2 populations. Further, we found high levels of G9a-dependent H3K9me2 at ILC3-specific genetic loci, demonstrating that G9a-mediated repression of ILC3-associated genes is critical for the optimal development of ILC2s. Together, these results provide the first identification of an epigenetic regulatory mechanism in ILC development and function

    Proučavanje 194Ir uhvatom termičkih neutrona I (d, p) reakcijom

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    Levels of 194Ir were studied using thermal neutron capture reaction. A pair spectrometer was used to measure the high-energy γ-ray spectrum from thermal-neutron capture in enriched 193Ir target over the energy range 4640 - 6100 keV. The low-energy γ-radiation from the reaction was studied with crystal diffraction spectrometers, and conversion electrons were observed with magnetic spectrometers. The high-sensitivity measurements at the Grenoble reactor, evaluated for transition energies up to 500 keV, are compared with lower-sensitivity measurements at the Wuerenlingen and Salaspils reactors. The comparison helped to obtain reliable isotopic identification for a number of 194Ir lines. The multipolarity admixtures for 29 γ-transitions were determined on the basis of conversion lines from different electron subshells. Prompt and delayed γ-γ coincidences were measured using semiconductor and scintillation detectors. The 193Ir(d,p) high-resolution spectra, observed with a magnetic spectrometer, are given. All these data contributed to establishing a detailed level scheme of 194Ir. Additional data and the interpretation of the results in terms of current models will be presented in a forthcoming paper.Proučavala su se stanja u 194Ir reakcijama 193Ir(n, γ) i 193Ir(d, p). Mjerenja uhvata termičkih neutrona načinjena su uz reaktore u Grenoblu, Wuerenlingenu i Salapsisu. Za mjerenja γ-zračenja visoke energije upotrebljavao se spektrometar parova, a za niske energije difraktometar. Konverzijske elektrone se mjerilo magnetskim spektrometrom. Mjerenja reakcije (d, p) visokog razlučivanja izvedena su magnetskim spektrometrom. Usporedbe tih mjerenja omogućile su pouzdano izotopno prepoznavanje prijelaza u 194 Ir, a spektri konverzijskih elektrona i određivanje multipolnosti prijelaza. Dobiveni su podaci osnova sheme raspada 194Ir
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