Quantum Tunneling Detection of Two-photon and Two-electron Processes

We analyze the operation of a quantum tunneling detector coupled to a coherent conductor. We demonstrate that in a certain energy range the output of the detector is determined by two-photon processes, two-electron processes and the interference of the two. We show how the individual contributions of these processes can be resolved in experiments.Comment: 4 pages, 4 figure

Hierarchical Models for Independence Structures of Networks

We introduce a new family of network models, called hierarchical network models, that allow us to represent in an explicit manner the stochastic dependence among the dyads (random ties) of the network. In particular, each member of this family can be associated with a graphical model defining conditional independence clauses among the dyads of the network, called the dependency graph. Every network model with dyadic independence assumption can be generalized to construct members of this new family. Using this new framework, we generalize the Erd\"os-R\'enyi and beta-models to create hierarchical Erd\"os-R\'enyi and beta-models. We describe various methods for parameter estimation as well as simulation studies for models with sparse dependency graphs.Comment: 19 pages, 7 figure

A randomised trial comparing laparoscopy with laparotomy in the management of women with ruptured ectopic pregnancy

Background. Ruptured ectopic pregnancy (REP) is a common gynaecological emergency in resource-poor settings, where laparotomy is the standard treatment despite laparoscopic surgery being regarded as the optimal treatment. There is a lack of prospective randomised data comparing laparoscopic surgery with laparotomy in the surgical management of women with REP.Objective. To compare operative laparoscopy with laparotomy in women with REP.Methods. This was a randomised parallel study. One hundred and forty women with suspected REP were randomised to undergo operative laparoscopy or laparotomy. The outcome measures were operating time, hospital stay, pain scores and analgesic requirements, blood transfusion, time to return to work, and time to full recovery.Results. Operating time was significantly longer in the laparoscopy group (67.3 v. 30.5 minutes, p<0.001). Duration of hospital stay, pain scores and need for analgesia were significantly less in the laparoscopy group. Women in this group returned to work 8 days earlier and their time to full recovery was significantly shorter compared with those in the laparotomy group. Significantly more women undergoing laparotomy required blood transfusion than women in the laparoscopy group. In the latter group, 14.5% of women required blood transfusion compared with 26.5% in the laparotomy group (p=0.01).Conclusion. Operative laparoscopy in women treated for REP is feasible in a resource-poor setting and is associated with significantly less morbidity and a quicker return to economic activity

Phase I of the DiaVACCS screening trial: Study design, methods, population demographics and baseline results

Background. Human papillomavirus (HPV)-based primary screening guidelines are based on screening test performance and prevalence data generated in high-resource areas with low HIV infection rates. There is an urgent need for local data on infection and disease prevalence, as well as screening test performance, among both HIV-positive and HIV-negative South African (SA) women, in order to inform updated screening guidelines. Objectives. This study describes the baseline characteristics of participants in the cross-sectional phase of the multicentric DIAgnosis in Vaccine And Cervical Cancer Screen (DiaVACCS) screening trial. The objective was to determine the prevalence of positive screening and pre-invasive disease using different tests and strategies in the SA HIV-positive and HIV-negative population.Methods. A total of 1  104 women aged 25 - 65 years and eligible for screening were included, 465 HIV positive and 639 HIV negative. Visual inspection and molecular and cytological screening tests were done on self-sampled and healthcare worker-collected specimens. All participants who screened positive and 49.1% of those who screened negative were invited for colposcopy and biopsy, and those qualifying for treatment were recalled for large loop excision of the transformation zone as part of the trial. The worst histology result for each participant was used, and for untested women, multiple imputation was used to estimate verification biasadjusted histology values.Results. Visual inspection was positive in 50.4% of HIV-positive v. 20.9% of HIV-negative women, cytology (atypical squamous cells of undetermined significance) in 39.9% v. 17.0%, and high-risk HPV DNA in 41.2% v. 19.6%. Overall, high-grade squamous intraepithelial lesion-positive cytology peaked in the age group 30 - 39 years at 16.7%. After adjustment for verification bias, histological diagnosis of cervical intraepithelial neoplasia (CIN)2+ was suspected in 44.7% v. 23.5% and CIN3+ in 23.3% v. 10.2% of HIV-positive and negative women, respectively. Invasive cancer was diagnosed in 15 women (1.95% of histological studies performed), and verification bias adjustment suggested 20 cases (1.8% of the study population).Conclusion. The baseline findings from the DiaVACCS trial confirm a high prevalence of HPV-related cervical pathology in the SA HIV-negative screening population, showing a clear need to reach these women with a screening programme. Among HIV-positive women, prevalence values were almost doubled. The prevalence of existing invasive cervical cancer was 1 - 2% of all women. Further analysis of the performance of single and multiple screening tests between the two subgroups will contribute to the choice of the most effective strategies to identify women at risk of developing invasive cancer

Evidence for strong f -d hybridization in intermetallic ferromagnet CePdIn2

Abstract: Please refer to full text to view abstract

Moving from atheoretical to theoretical approaches to interprofessional client-centred collaborative practice

In this chapter we revisit the importance of theory in the development of interprofessional client centred education and practice (IPCEP). We focus specifically on the theoretical underpinnings and development of a workshop model aimed at moving practitioners from atheoretical to theoretical collaborative practice

A randomised controlled trial comparing laparoscopy with laparotomy in the management of women with ruptured ectopic pregnancy

Letter by Odejinmi and Oliver on article by Snyman et al. (Snyman LC, Makulana T, Makin JD. A randomised trial comparing laparoscopy with laparotomy in the management of women with ruptured ectopic pregnancy. S Afr Med J 2017;107(3):258-263. https://doi.org/10.7196/SAMJ.2017.v107i3.11447); and response by Snyman et al

The Keldysh action of a multi-terminal time-dependent scatterer

We present a derivation of the Keldysh action of a general multi-channel time-dependent scatterer in the context of the Landauer-B\"uttiker approach. The action is a convenient building block in the theory of quantum transport. This action is shown to take a compact form that only involves the scattering matrix and reservoir Green functions. We derive two special cases of the general result, one valid when reservoirs are characterized by well-defined filling factors, the other when the scatterer connects two reservoirs. We illustrate its use by considering Full Counting Statistics and the Fermi Edge Singularity.Comment: 13 pages, 2 figures, submitted to PR

Coherent Stranski-Krastanov growth in 1+1 dimensions with anharmonic interactions: An equilibrium study

The formation of coherently strained three-dimensional islands on top of the wetting layer in Stranski-Krastanov mode of growth is considered in a model in 1+1 dimensions accounting for the anharmonicity and non-convexity of the real interatomic forces. It is shown that coherent 3D islands can be expected to form in compressed rather than in expanded overlayers beyond a critical lattice misfit. In the latter case the classical Stranski-Krastanov growth is expected to occur because the misfit dislocations can become energetically favored at smaller island sizes. The thermodynamic reason for coherent 3D islanding is the incomplete wetting owing to the weaker adhesion of the edge atoms. Monolayer height islands with a critical size appear as necessary precursors of the 3D islands. The latter explains the experimentally observed narrow size distribution of the 3D islands. The 2D-3D transformation takes place by consecutive rearrangements of mono- to bilayer, bi- to trilayer islands, etc., after exceeding the corresponding critical sizes. The rearrangements are initiated by nucleation events each next one requiring to overcome a lower energetic barrier. The model is in good qualitative agreement with available experimental observations.Comment: 12 pages text, 15 figures, Accepted in Phys.Rev.B, Vol.61, No2