A Diffusion Approximation for a Markovian Queue with Reneging

Consider a single-server queue with a Poisson arrival process and exponential processing times in which each customer independently reneges after an exponentially distributed amount of time. We establish that this system can be approximated by either a reflected Ornstein–Uhlenbeck process or a reflected affine diffusion when the arrival rate exceeds or is close to the processing rate and the reneging rate is close to 0. We further compare the quality of the steady-state distribution approximations suggested by each diffusion.     

A cryogenic underground observatory for rare events: CUORE, an update

CUORE is a proposed tightly packed array of 1000 TeO₂ bolometers, each being a cube 5 cm on a side with a mass of 750 g. The array consists of 25 vertical towers, arranged in a square of 5 towers by 5 towers, each containing ten layers of four crystals. The design of the detector is optimized for ultralow-background searches for neutrinoless double beta decay of ¹³⁰Te (33.8% abundance), cold dark matter, solar axions, and rare nuclear decays. A preliminary experiment involving 20 crystals of various sizes (MIBETA) has been completed, and a single CUORE tower is being constructed as a smaller scale experiment called CUORICINO. The expected performance and sensitivity, based on Monte Carlo simulations and extrapolations of present results, are reported.     

Average g-factors for high-spin states in 78Kr

Inverse reactions of ^{63, 65}Cu beams on ^{18, 16}O targets have been used to populate states of ⁷⁸Kr by fusion-evaporation reactions. The excited nuclei recoiled at high velocity v/c ≈ 7 % through a polarized iron (⁵⁴Fe) layer and were stopped in a copper layer. During the period in iron, 0.05–0.65 ps, the nuclei were subjected to the intense transient magnetic field (initially ～ 3500 T). The resulting precession of the high-spin nuclear states populated during this time was determined by measuring the time integral rotation angle of the discrete γ-ray transitions at low spin.The average g-factor at low spin 2 ≦ J ≦ 8 compared to that at higher spin 8 ≦ J ≦ 12 in ⁷⁸Kr was found to be identical within the experimental uncertainties of ～ 15 %. This result implies that either there are no rotational alignment effects at the backbend in ⁷⁸Kr or more plausibly, proton (g ≈ 1) and neutron (g ≈ 0) aligned bands are equally competitive and both populated in the reaction. It is then likely that the resulting g-factor represents an average over many populated proton and neutron aligned bands.     

On the temperature dependence of the activation enthalpy for sucrose hydrolysis

Recent interest in the measurement and the interpretation of heat capacities of activation has led to more rigorous methods to detect temperature-varient activation parameters. One such method devised by Blandamer and co-workers was applied to the sucrose hydrolysis data of Moelwyn-Hughes and Leininger and Kilpatrick. Both sets of investigators claimed that the energy of activation for sucrose inversion decreased with increasing temperature, while Heidt and Purvis and more recently, Kuhler's group contend that the energy of activation is constant. It was found that neither the data of Moelwyn-Hughes nor of Leininger and Kilpatrick warrant the inclusion of a temperature-dependent activation enthalpy.     

Current and Charge Distributions along an Antenna in a Cylinder of Cold Plasma

The analysis of the insulated antenna in a relatively dense medium is modified to apply to a thin cylindrical dipole antenna (radius a, length 2h) in a glass tube filled with a homogeneous cold plasma. Account is taken of the finite radius b of the plasma column and of the thickness (c - b) of the containing tube. Complex wave numbers, distributions of current and charge, and driving-point admittances have been calculated for dipoles with electrical lengths up to two wavelengths with 3 ? b/a ? 28, 0.75 ? (?p/?)2 ? 1.05, and 0.01 ? ?/?p ? 0.10. The effect of the thickness and permittivity of the glass tube on the wave number and admittance is determined. Numerous graphs and tables are provided.     

The Abramov-Rokhlin entropy addition formula for amenable group actions

In this note we show that the entropy of a skew product action of a countable amenable group satisfies the classical formula of Abramov and Rokhlin.     

Ansätze for self-dual Yang-Mills fields

A sequenceA ₁,A ₂, ... of ansätze for generating self-dual solutions of the Yang-Mills equations is presented. For eachn,A _n produces a solution depending on two arbitrary functions of three variables. As an application, we see thatA ₂ generates a static Yang-Mills-Higgs 2-monopole solution.     

g-Factor for the K=6, Jπ=6+ isomer in178Hf

Hyperfine Interactions -