65,059 research outputs found
Oil and international cooperation
The more that states depend on oil exports, the less cooperative they become: they grow less likely to join intergovernmental organizations, to accept the compulsory jurisdiction of international judicial bodies, and to agree to binding arbitration for investment disputes. This pattern is robust to the use of country and year fixed effects, to alternative measures of the key variables, and to the exclusion of all countries in the Middle East. To explain this pattern, we consider the economic incentives that foster participation in international institutions: the desire to attract foreign investment and to gain access to foreign markets. Oil-exporting states, we argue, find it relatively easy to achieve these aims without making costly commitments to international institutions. In other words, natural resource wealth liberates states from the economic pressures that would otherwise drive them toward cooperation
Derivation of the probability distribution function for the local density of states of a disordered quantum wire via the replica trick and supersymmetry
We consider the statistical properties of the local density of states of a
one-dimensional Dirac equation in the presence of various types of disorder
with Gaussian white-noise distribution. It is shown how either the replica
trick or supersymmetry can be used to calculate exactly all the moments of the
local density of states. Careful attention is paid to how the results change if
the local density of states is averaged over atomic length scales. For both the
replica trick and supersymmetry the problem is reduced to finding the ground
state of a zero-dimensional Hamiltonian which is written solely in terms of a
pair of coupled ``spins'' which are elements of u(1,1). This ground state is
explicitly found for the particular case of the Dirac equation corresponding to
an infinite metallic quantum wire with a single conduction channel. The
calculated moments of the local density of states agree with those found
previously by Al'tshuler and Prigodin [Sov. Phys. JETP 68 (1989) 198] using a
technique based on recursion relations for Feynman diagrams.Comment: 39 pages, 1 figur
Electroweak Breaking in Supersymmetric Models
We discuss the mechanism for electroweak symmetry breaking in supersymmetric
versions of the standard model. After briefly reviewing the possible sources of
supersymmetry breaking, we show how the required pattern of symmetry breaking
can automatically result from the structure of quantum corrections in the
theory. We demonstrate that this radiative breaking mechanism works well for a
heavy top quark and can be combined in unified versions of the theory with
excellent predictions for the running couplings of the model. (To be published
in ``Perspectives in Higgs Physics'', G. Kane editor.)Comment: 47 page
Intra- and Intermolecular C−H Activation by Bis(phenolate)pyridineiridium(III) Complexes
A bis(phenolate)pyridine pincer ligand (henceforth abbreviated as ONO) has been employed to support a variety of iridium complexes in oxidation states I, III, and IV. Complexes (ONO)IrL_2Me (L = PPh_3, PEt_3) react with I_2 to cleave the Ir–C bond and liberate MeI, apparently via a mechanism beginning with electron transfer to generate an intermediate Ir(IV) complex, which can be isolated and characterized for the case L = PEt_3. The PPh_3 complex is transformed in benzene at 65 °C to the corresponding phenyl complex, with loss of methane, and subsequently to a species resulting from metalation of a PPh_3 ligand. Labeling and kinetics studies indicate that PPh_3 is the initial site of C–H activation, even though the first observed product is that resulting from intermolecular benzene activation. C–H activation of acetonitrile has also been observed
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