Recoil Distributions in Particle Transfer

Classical Thomas peaks in various fast second-order particle transfer processes are quantum mechanically broadened by energy nonconservation in the intermediate states of collision. This quantum broadening is considered in observable velocity distributions of recoil particles

Men's Experiences of the UK Criminal Justice System Following Female-Perpetrated Intimate Partner Violence

© 2015 Springer Science+Business Media New York The current study aimed to explore men’s experience of the UK Criminal Justice System (CJS) following female-perpetrated intimate partner violence (IPV). Unstructured face-to-face and Skype interviews were conducted with six men aged between 40–65 years. Interviews were transcribed and analysed using interpretative phenomenological analysis (IPA). Due to the method of analysis and the sensitive nature of the research, the researcher engaged in a process of reflexivity. Four main themes were identified, including ‘Guilty until Proven Innocent: Victim Cast as Perpetrator;’ ‘Masculine Identity;’ ‘Psychological Impact’ and ‘Light at the End of the Tunnel.’ Themes were discussed and illustrated with direct quotes drawn from the transcripts. Directions for future research, criminal justice interventions, and therapeutic interventions were discussed

Study protocol for the evaluation of an Infant Simulator based program delivered in schools: a pragmatic cluster randomised controlled trial

Background: This paper presents the study protocol for a pragmatic randomised controlled trial to evaluate the impact of a school based program developed to prevent teenage pregnancy. The program includes students taking care of an Infant Simulator; despite growing popularity and an increasing global presence of such programs, there is no published evidence of their long-term impact. The aim of this trial is to evaluate the Virtual Infant Parenting (VIP) program by investigating pre-conceptual health and risk behaviours, teen pregnancy and the resultant birth outcomes, early child health and maternal health. Methods and Design: Fifty-seven schools (86% of 66 eligible secondary schools) in Perth, Australia were recruited to the clustered (by school) randomised trial, with even randomisation to the intervention and control arms. Between 2003 and 2006, the VIP program was administered to 1,267 participants in the intervention schools, while 1,567 participants in the non-intervention schools received standard curriculum. Participants were all female and aged between 13-15 years upon recruitment. Pre and post-intervention questionnaires measured short-term impact and participants are now being followed through their teenage years via data linkage to hospital medical records, abortion clinics and education records. Participants who have a live birth are interviewed by face-to-face interview. Kaplan-Meier survival analysis and proportional hazards regression will test for differences in pregnancy, birth and abortion rates during the teenage years between the study arms.Discussion: This protocol paper provides a detailed overview of the trial design as well as initial results in the form of participant flow. The authors describe the intervention and its delivery within the natural school setting and discuss the practical issues in the conduct of the trial, including recruitment. The trial is pragmatic and will directly inform those who provide Infant Simulator based programs in school settings

Formation of Positronium in e+ + H- Collisions

Cross sections for positronium formation by capture from the negative hydrogen ion are given. Orthogonalization corrections to the Coulomb (first-order) Born approximation (CBA) differential and total cross sections are calculated using approximate H- wave functions of both Löwdin [Phys. Rev. 90, 123 (1953)] and Chandrasekhar [Astrophys. J. 100, 176 (1944)]. The present calculation of the CBA cross sections using the post interaction for Löwdin’s wave function (LCBAPS) disagrees with the calculation of Choudhury, Mukherjee, and Sural (CMS) [Phys. Rev. A 33, 2358 (1986)], whereas our results using the prior interaction agree. Thus, where CMS found an order of magnitude post-prior discrepancy in the differential cross sections except at forward angles, and a markedly different shape to the minima, the present post and prior results differ by 1–10 % at 100 eV, and the minima have the same shape and occur within one degree of each other. Chandrasekhar’s ‘‘open-shell’’ wave function, which is superior to Löwdin’s in bound-state problems since it gives a negative binding energy, gives post and prior cross sections that are almost indistinguishable at this energy and are 1/2 to 2/3 as large as the LCBA. Various methods of orthogonalizing the unbound projectile to the possible bound states are considered. It is found that treating the atomic nuclei as if they were isotopic spin projections [Straton and Girardeau, Phys. Rev. A 40, 2991 (1989)] of a single type of ‘‘nucleon’’ gives cross sections that are an improvement over the CBA

Ionization-excitation of helium by fast charged particles

Probabilities and cross sections for ionization plus excitation in helium produced by fast heavy-particle impact have been evaluated. In these calculations, contributions from shake-off, time ordering, and independent interactions of the frozen-target electrons with the projectile are included. A comparison is made to recent experimental observations for the ratio of excitation-ionization to single-ionization total cross sections. A comparison is also made to calculations of excitation-ionization by fast electron impact

Fock-Tani Transformation and a First-Order Theory of Charge Transfer

A unitary (Fock-Tani) transformation of the second-quantized Hamiltonian breaks the interaction into its component parts, e.g., elastic scattering, inelastic scattering, rearrangement interaction, etc. The interaction for a particular process is ‘‘weaker’’ than the overall interaction; this is reflected in certain orthogonality corrections which appear in a perturbation expansion of the T-matrix element. As a result, the internuclear potential makes a negligible contribution of order me/mp to the first-order amplitude for charge transfer. We find very good agreement with experimental and the best available theoretical results for the total cross section for the reaction p+H(1s)→H(1s)+p for energies greater than 10 keV and for the differential cross section at 25, 60, and 125 keV in an angular range of ∼1 mrad about the forward direction

Space and time correlation in high velocity multiple electron transitions

In collisions of high velocity projectiles of charge Z and velocity v, perturbations expansions in Z/v usually converge when Z/v<l. Under these conditions Z[sup 3] contributions to cross sections for two electron transitions (e.g. double excitation) may arise if there is interference between first order and second order contributions to the probability amplitude. Non-zero Z[sup 3] terms in two electron excitation or ionization cross sections occur if spatial electron correlation is present. For double excitation non-zero Z[sup 3] contributions require a correlation in time as well. This time correlation corresponds to quantum time ordering arising from virtual off-energy-shell intermediate states. As with second order amplitudes for Thomas singularities in single electron capture, the energy non-conserving amplitude is connected to the energy-conserving amplitude in second order in Z by a dispersion relation. Generalization to higher order transitions (e.g. triple excitation) is discussed

Space and time correlation in high velocity multiple electron transitions

In collisions of high velocity projectiles of charge Z and velocity v, perturbations expansions in Z/v usually converge when Z/v<l. Under these conditions Z{sup 3} contributions to cross sections for two electron transitions (e.g. double excitation) may arise if there is interference between first order and second order contributions to the probability amplitude. Non-zero Z{sup 3} terms in two electron excitation or ionization cross sections occur if spatial electron correlation is present. For double excitation non-zero Z{sup 3} contributions require a correlation in time as well. This time correlation corresponds to quantum time ordering arising from virtual off-energy-shell intermediate states. As with second order amplitudes for Thomas singularities in single electron capture, the energy non-conserving amplitude is connected to the energy-conserving amplitude in second order in Z by a dispersion relation. Generalization to higher order transitions (e.g. triple excitation) is discussed

Third-Order Pseudostate Calculation Of Excitation-Ionization Of Helium By Protons And Antiprotons

Techniques the authors developed to include correlation in the double-excitation of atoms are applied to a second two-electron process, excitation–ionization by proton versus antiproton impact. The second-order cross section, in the closure approximation and using pseudostates for the unbound electron, reproduces only a small percentage of the experimental factor of 2 difference for positively versus negatively charged projectiles. Inclusion of a portion of the third-order term yields a significant contribution near 0.5 MeV