Spins and mixing ratios in 138Ba

The spin assignments to the 1899 (4⁺), 2308 (3⁺ or 4⁺) and 2446 (3⁺) keV levels in ¹³⁸Ba have been confirmed by γ-γ directional correlation measurements. In addition, the multipolarity and $\text{E2}\text{M1}$ mixing parameters for a number of transitions have been established as follows: 409 keV (M1+E2, ?0.75 < δ < ?0.45 or ?0.85 < δ < ?0.05 depending on the choice of J^π = 3⁺ or 4⁺ for the initial state), 463 keV (E2, 0 < δ < 0.15 for $\text{M3}\text{E2}$ admixture), 547 keV (M1+E2, ?0.06 < δ < ?0.015), 872 keV (M1+E2, δ undefined) and 1010 keV (M1+E2, ?0.015 < δ < +0.020).     

An integrated approach to shift-starting time selection and tour-schedule construction

A common practice in personnel tour scheduling is to limit the number of permissible daily shift starting times. Accordingly, an important subproblem that arises in tour-scheduling problems is the selection of those starting times that are conducive to efficient satisfaction of labour requirements. A previously published heuristic for this problem is sequential in nature, whereby a subset of starting times is selected in the first stage and tours are constructed using the chosen starting times in the second stage. We propose an integrative procedure that overcomes many of the limitations inherent in the sequential approach. Our procedure, which uses tabu search for starting time selection and a cutting plane method for tour construction, was compared to integer programming and the previously published heuristic in two experiments using test conditions from the airport staffing literature. Although all methods performed well when the labour requirement patterns were consistent across days of the week, the new procedure yielded the best performance when such patterns were inconsistent.     

A rapid,chromatography-free route to substituted acridine–isoalloxazine conjugates under microwave irradiation

Microwave irradiation was applied to a sequence of condensation reactions from readily available 9-chloroacridines to provide a range of novel acridine–isoalloxazine conjugates. The combination of these two moieties, both of biological interest, was achieved by a chromatography-free route.     

On the determination of the tidal amplitude in a river estuary having an irregular topography

A method based upon the balance of mechanical energy is used to calculate the local tidal amplitude in a river estuary. The technique permits the specification of an irregular topography and variable coefficient of eddy viscosity in the landward direction. Numerical calculations are performed for a river having the approximate dimensions of the Thames between Southend and Teddington. The fitting of the topography involves the specification of the mean width and depth by a suitable functional law along the river. The parametric representation of the turbulence may be quantified by prescribing that the local eddy viscosity be proportional to the local mean depth. The resulting evaluations are then used to assess the effect upon the tidal dynamics of nonuniformities in the topography and structure of the turbulence.     

The Synthesis of 4-Amino-2-methyl-3-(1-oxo) Pent-4-ynyl-5,6,7,8-tetrahydrobenzo[b]thieno[2,3-b]pyridine

The synthesis of ketone 1 from the ethyl ester of 4-amino-2-methyl-5,6,7,8-tetrahydrobenzo[b]thieno[2,3-b]pyridine-3-carboxylic acid using β-ketosulfone methodology is described.     

The ν2 and ν4 bands of AsH3

The infrared absorption of arsine, AsH₃, between 750 and 1200 cm^?1 has been recorded at a resolution of 0.006 cm^?1. Altogether 2419 transitions, including nearly 700 “perturbation allowed” transitions with Δ∥k ? l∥ = ±3, ±6, and ±9, have been assigned to the ν₂(A₁) and ν₄(E) bands. Splitting of the transitions for K″ = 3, 6, and 9 was also observed. To fit the rotational pattern of the v₂ = 1 and v₄ = 1 vibrational states up to J = 21, all the experimental data were analyzed simultaneously on the basis of a rovibrational Hamiltonian which took into account the Coriolis interaction between ν₂ and ν₄ and also included several essential resonances within them. The derived set of 38 significant spectroscopic parameters reproduced the 2328 transition wavenumbers retained in the final fit within the accuracy of the experimental measurements.     

A consistent RPA formalism

This paper examines the quasi-boson and generator-coordinate derivations of the RPA and concludes that they make uncritical and inconsistent use of the assumption that ground state correlations be small. It is proposed that consistent derivations of the RPA to various orders can be carried out by explicit retention of a certain power of a parameter γ which is proportional to the norm of the ground state correlations. To illustrate such a method, it is proved that a consistent, non-trivial, linear RPA theory exists only if the residual potential is small enough for first order perturbation theory to be valid.