On Properties of the Isoscalar Giant Dipole Resonance

Main properties (strength function, energy-dependent transition density, branching ratios for direct nucleon decay) of the isoscalar giant dipole resonance in several medium-heavy mass spherical nuclei are described within a continuum-RPA approach, taking into account the smearing effect. All model parameters used in the calculations are taken from independent data. Calculation results are compared with available experimental data.Comment: 12 pages, 2 figure

Inviting end-of-life talk in initial CALM therapy sessions: A conversation analytic study

OBJECTIVE: To examine how end-of-life talk is initiated in CALM therapy sessions with advanced cancer patients. METHODS: Conversation analysis was used to systematically examine the sequences where talk about death was raised in the first sessions of ten patients. RESULTS: Open questions about the patients' experiences, feelings or understanding in the context of talk about their troubles, were found to regularly elicit talk concerning end-of-life. These questions were designed in ways that invite patients to discuss troubling aspects of their cancer journey, without making discussion of this topic an interactional requirement. That is, the interactional work required to not engage in such talk is minimised. This choice is provided through the open question design, the degree to which negative feeling descriptors are specified, and the sequential context of the question. CONCLUSION: The analysis shows that therapists provide patients with the opportunity to talk about end-of-life in a way that is supportive of the therapeutic relationship. The readiness of patients to engage in end-of-life talk displays the salience of this topic, as well as the reflective space provided by CALM therapy. PRACTICE IMPLICATIONS: The results provide important insight into the process of CALM therapy, which can be used to guide training

Evaluation of the mean intensity of the P-odd mixing of nuclear compound states

A temperature version of the shell-optical-model approach for describing the low-energy compound-to-compound transitions induced by external single-particle fields is given. The approach is applied to evaluate the mean intensity of the P-odd mixing of nuclear compound states. Unified description for the mixing and electromagnetic transitions allows one to evaluate the mean intensity without the use of free parameters. The valence-mechanism contribution to the mentioned intensity is also evaluated. Calculation results are compared with the data deduced from cross sections of relevant neutron-induced reactions.Comment: LaTeX, 10 page

Numerical studies of variable-range hopping in one-dimensional systems

Hopping transport in a one-dimensional system is studied numerically. A fast algorithm is devised to find the lowest-resistance path at arbitrary electric field. Probability distribution functions of individual resistances on the path and the net resistance are calculated and fitted to compact analytic formulas. Qualitative differences between statistics of resistance fluctuations in Ohmic and non-Ohmic regimes are elucidated. The results are compared with prior theoretical and experimental work on the subject.Comment: 12 pages, 12 figures. Published versio

Pulsar timing analysis in the presence of correlated noise

Pulsar timing observations are usually analysed with least-square-fitting procedures under the assumption that the timing residuals are uncorrelated (statistically "white"). Pulsar observers are well aware that this assumption often breaks down and causes severe errors in estimating the parameters of the timing model and their uncertainties. Ad hoc methods for minimizing these errors have been developed, but we show that they are far from optimal. Compensation for temporal correlation can be done optimally if the covariance matrix of the residuals is known using a linear transformation that whitens both the residuals and the timing model. We adopt a transformation based on the Cholesky decomposition of the covariance matrix, but the transformation is not unique. We show how to estimate the covariance matrix with sufficient accuracy to optimize the pulsar timing analysis. We also show how to apply this procedure to estimate the spectrum of any time series with a steep red power-law spectrum, including those with irregular sampling and variable error bars, which are otherwise very difficult to analyse.Comment: Accepted by MNRA

An analysis of the timing irregularities for 366 pulsars

We provide an analysis of timing irregularities observed for 366 pulsars. Observations were obtained using the 76-m Lovell radio telescope at the Jodrell Bank Observatory over the past 36 years. These data sets have allowed us to carry out the first large-scale analysis of pulsar timing noise over time scales of > 10yr, with multiple observing frequencies and for a large sample of pulsars. Our sample includes both normal and recycled pulsars. The timing residuals for the pulsars with the smallest characteristic ages are shown to be dominated by the recovery from glitch events, whereas the timing irregularities seen for older pulsars are quasi-periodic. We emphasise that previous models that explained timing residuals as a low-frequency noise process are not consistent with observation.Comment: Accepted by MNRAS. High resolution images available from the article on AD

The gamma-ray telescope Gamma-1

French and Soviet specialists have designed and built the gamma-ray telescope GAMMA-1 to detect cosmic gamma rays above 50 MeV. The sensitive area of the detector is 1400 sq cm, energy resolution is 30% at 300 MeV, and angular resolution 1.2 deg at 300 MeV (and less than 20' arc when a coded aperture mask is used). Results on calibration of the qualification model and Monte-Carlo calculations are presented

Tunneling-assisted impact ionization fronts in semiconductors

We propose a novel type of ionization front in layered semiconductor structures. The propagation is due to the interplay of band-to-band tunneling and impact ionization. Our numerical simulations show that the front can be triggered when an extremely sharp voltage ramp ($\sim 10 {\rm kV/ns}$) is applied in reverse direction to a Si $p^+-n-n^+-$structure that is connected in series with an external load. The triggering occurs after a delay of 0.7 to 0.8 ns. The maximal electrical field at the front edge exceeds $10^6 {\rm V/cm}$. The front velocity $v_f$ is 40 times faster than the saturated drift velocity $v_s$. The front passes through the $n-$base with a thickness of $100 {\mu m}$ within approximately 30 ps, filling it with dense electron-hole plasma. This passage is accompanied by a voltage drop from 8 kV to dozens of volts. In this way a voltage pulse with a ramp up to $500 {\rm kV/ns}$ can be applied to the load. The possibility to form a kilovolt pulse with such a voltage rise rate sets new frontiers in pulse power electronics.Comment: 12 pages, 6 figure

The Effect of the Pairing Interaction on the Energies of Isobar Analog Resonances in 112−124^{112-124}Sb and Isospin Admixture in 100−124^{100-124}Sn Isotopes

In the present study, the effect of the pairing interaction and the isovector correlation between nucleons on the properties of the isobar analog resonances (IAR) in $^{112-124}$Sb isotopes and the isospin admixture in $^{100-124}$Sn isotopes is investigated within the framework of the quasiparticle random phase approximation (QRPA). The form of the interaction strength parameter is related to the shell model potential by restoring the isotopic invariance of the nuclear part of the total Hamiltonian. In this respect, the isospin admixtures in the $^{100-124}$Sn isotopes are calculated, and the dependence of the differential cross section and the volume integral $J_{F}$ for the Sn($^{3}$He,t)Sb reactions at E($^{3}$He)$=200$ MeV occurring by the excitation of IAR on mass number A is examined. Our results show that the calculated value for the isospin mixing in the $^{100}$Sn isotope is in good agreement with Colo et al.'s estimates $(4-5$, and the obtained values for the volume integral change within the error range of the value reported by Fujiwara et al. (53$\pm$5 MeV fm$^{3}$). Moreover, it is concluded that although the differential cross section of the isobar analog resonance for the ($^{3}$He,t) reactions is not sensitive to pairing correlations between nucleons, a considerable effect on the isospin admixtures in $N\approx Z$ isotopes can be seen with the presence of these correlations.Comment: 16 pages, 5 EPS figures and 2 tables, Late