Portfolio Optimization With a Guaranteed Minimum Maturity Benefit and Risk-Adjusted Fees

Methodology and Computing in Applied Probability - We study a portfolio optimization problem involving the loss averse policyholder of a variable annuity with a guaranteed minimum maturity benefit....     

Observation of slowed rotation about the (η6-arene)-chromium bond in the chromium tricarbonyl complex of thesyn-anti-syn trimer of bicyclo[2.2.1]hept-2-yne

Summary The crystal and molecular structures are reported for the chromium tricarbonyl complexes of the sterically-demanding and rigidsyn-anti-syn andall-syn trimers of bicyclo[2.2.1]hept-2-yne, (3-Cr) and (4-Cr). At very low temperatures, a decoalescence phenomenon occurs in the 75.49 MHz¹³C-{¹H}-NMR spectrum of (3-Cr) and is unambiguously assigned to slowed rotation about the (⁶-arene)-chromium bond.Dedicated to Professor Dr. Karl Schlögl on the occasion of his 65th birthday     

Confirmation of selective site occupation of dilute Co impurities in Fe3Si using the Mössbauer effect technique

The distribution of a dilute solution of Co impurities in Fe₃Si is investigated by means of a Mössbauer source experiment. The results suggest that all Co impurities selectively replace Fe_II site atoms in the lattice, in agreement with NMR data of Burch et al.,⁷ whereas neutron diffraction experiments in more heavily doped material do not preclude the possibility of a lesser degree of preferential substitution.     

Enantioselective acylation using a second-generation P-aryl-2-phosphabicyclo[3.3.0]octane catalyst

The synthesis of P-aryl-2-phosphabicylco[3.3.0]octane x HBF4 salts 3a and 3c is described. Incorporation of the P-3,5-di-tert-butyl-4-methoxyphenyl group in 3c allows use of a less expensive aryl bromide starting material. Deprotonation of the air-stable salts in situ with triethylamine releases the corresponding phosphines 1a and 1c for use in the kinetic resolution of representative secondary alcohols. The method is convenient for small-scale experiments and affords enantioselectivities s close to the values obtained using the free phosphines 1a and 1b in cases where s is ca. 40 or lower.     

Symplectic twist maps without conjugate points

For sequences of symplectic twist maps without conjugate points, an invariant Lagrangian subbundle is constructed. This allows one to deduce that absence of conjugate points is a rare property in some classes of maps. This work was partially supported by EPSRC grant GR/M11349.     

Category restructuring during second-language speech acquisition

This study examined the production of English /b/ and the perception of short-lag English /b d g/ tokens by four groups of bilinguals who differed according to their age of arrival (AOA) in Canada from Italy and amount of self-reported native language (L1) use. A clear difference emerged between early bilinguals (mean AOA= 8 years) and late bilinguals (mean AOA= 20 years). The late bilinguals showed a stronger L1 influence than the early bilinguals did on both the production and perception of English stops. In experiment 2, the late bilinguals produced a larger percentage of prevoiced English /b/ tokens than early bilinguals and native English (NE) speakers did. In experiment 3, the late bilinguals misidentified short-lag English /b d g/ tokens as /p t k/ more often than the early bilinguals and NE speakers did. Experiment 4 revealed that the frequencies with which the bilinguals prevoiced /b d g/ in Italian and English were correlated. The observed differences between the early and late bilinguals were attributed to differences in the quantity and quality of English phonetic input they had received, not to a greater likelihood by the early than late bilinguals to establish new phonetic categories for English /b d g/.     

Supporting complex group decisions: A probabilistic multi-dimensional scaling approach

Groups often face complex decisions; decisions in which the decision alternatives are not clearly defined and the criteria for choosing an alternative are subject to dispute within the group. We present a Group Decision Support System that will use judgments from the group to visualize the decision problem in a probabilistic geometric space. In this geometric representation, actual decision alternatives and an ideal alternative—an artificial alternative that identifies the ideal solution to the group's decision dilemma—are portrayed as distributions in a multi-dimensional space. Dispersions of the distributions measure the uncertainties of the decision process. The psychometric theory used to develop the probabilistic geometric representation is described. Preliminary research is presented which demonstrates that geometric representations of this type help groups both to understand better the decision they face and to find better solutions.     

Coexistence of superconductivity and long-range magnetic order in TmRh4B4

Electrical resistance, heat capacity, thermal conductivity and linear thermal expansion coefficient measurements on TmRh₄B₄ indicate that superconductivity and long-range magnetic order coexist in this compound for temperatures less than 0.4 K.