Numerical evaluation of three non-coaxial kinematic models using the distinct element method for elliptical granular materials

This is the accepted version of the following article: [Jiang, M. J., Liu, J. D., and Arroyo, M. (2016) Numerical evaluation of three non-coaxial kinematic models using the distinct element method for elliptical granular materials. Int. J. Numer. Anal. Meth. Geomech., 40: 2468–2488. doi: 10.1002/nag.2540.], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/nag.2540/fullThis paper presents a numerical evaluation of three non-coaxial kinematic models by performing Distinct Element Method (DEM) simple shear tests on specimens composed of elliptical particles with different aspect ratios of 1.4 and 1.7. The models evaluated are the double-shearing model, the double-sliding free-rotating model and the double slip and rotation rate model (DSR2 model). Two modes of monotonic and cyclic simple shear tests were simulated to evaluate the role played by the inherent anisotropy of the specimens. The main findings are supported by all the DEM simple shear tests, irrespective of particle shape, specimen density or shear mode. The evaluation demonstrates that the assumption in the double-shearing model is inconsistent with the DEM results and that the energy dissipation requirements in the double-sliding free-rotating model appear to be too restrictive to describe the kinematic flow of elliptical particle systems. In contrast, the predictions made by the DSR2 model agree reasonably well with the DEM data, which demonstrates that the DSR2 model can effectively predict the non-coaxial kinematic behavior of elliptical particle systems.Peer ReviewedPostprint (author's final draft

Association of Fasciola hepatica Infection with Liver Fibrosis, Cirrhosis, and Cancer: A Systematic Review

Background: Fascioliasis has been sporadically associated with chronic liver disease on previous studies. In order to describe the current evidence, we carried out a systematic review to assess the association between fascioliasis with liver fibrosis, cirrhosis and cancer. Methodology and Principal Findings: A systematic search of electronic databases (PubMed, LILACS, Scopus, Embase, Cochrane, and Scielo) was conducted from June to July 2015 and yielded 1, 557 published studies. Among 21 studies that met inclusion and exclusion criteria, 12 studies explored the association of F. hepatica with liver fibrosis, 4 with liver cirrhosis, and 5 with cancer. Globally these studies suggested the ability of F. hepatica to promote liver fibrosis and cirrhosis. The role of F. hepatica in cancer is unknown. Given the heterogeneity of the studies, a meta-analysis could not be performed. Conclusions: Future high-quality studies are needed to determine the role of F. hepatica on the development of liver fibrosis, liver cirrhosis, and cancer in humans

New insight on pseudospin doublets in nuclei

The relevance of the pseudospin symmetry in nuclei is considered. New insight is obtained from looking at the continuous transition from a model satisfying the spin symmetry to another one satisfying the pseudospin symmetry. This study suggests that there are models allowing no missing single-particle states in this transition, contrary to what is usually advocated. It rather points out to an association of pseudospin partners different from the one usually assumed, together with a strong violation of the corresponding symmetry. A comparison with results obtained from some relativistic approaches is made.Comment: 27 pages, 18 figure

Evaluation of the SUNHEART Cardiology Outreach Programme

Introduction: The demand for advanced cardiac care and specialised interventions is on the increase and this results in bottlenecks and increased waiting times for patients who require advanced cardiac care. By decentralising cardiac care, and using a hub-and-spoke model, the SUNHEART Outreach Programme of cardiovascular care aims to improve access to advanced cardiac care in the Western Cape. Tygerberg Hospital is the central hub, with the fi rst spoke being Paarl Hospital. Objective: To determine the value of the SUNHEART Outreach Programme to the public health care system. Methods: An audit of patients accessing the OutreachProgramme was performed for the period May 2013 - May 2014 and consequently compared to a historical cohort of patients accessing the health care system during the preceding 6 months, from October 2012 -April 2013. Access to advanced cardiac care was measured in time to initial evaluation, time to defi nitive diagnosis or intervention and patient compliance with appointments. The value to the health care system was also assessed by performing a cost analysis of transport of patients and health care workers, as well as compliance with appointments. We documented the spectrum of disease requiring advanced cardiac care toguide future interventions. Results: Data of 185 patients were included in the audit. Sixty four patients were referred to tertiary care from October 2012 - April 2013 and 121 patients were referred to the outreach facility from May 2013 - May 2014. There was a signifi cant reduction in waiting times with the median days to appointment of the historical cohort being 85 days compared to 18 days in the Outreach Programme cohort (p<0.01). Patient compliance with appointments was signifi cantly superior in the Outreach Programme cohort (90% vs. 56%: p<0.01). Valvular (36.5%) and ischaemic heart disease (35.5%) were the major pathologies requiring access to cardiac care services. Transport costs per patient treated was signifi cantly reduced in the outreach programme cohort (R118,09 vs. R308,77). Conclusion: Decentralisation of services in the form of an Outreach Programme, with a central hub, improves access to advanced cardiac care by decreasing waiting time, improving compliance with appointments and decreasing travel costs

Successful Yukawa structures in Warped Extra Dimensions

For a RS model, with SM fields in the bulk and the Higgs boson on the TeV-brane, we suggest two specific structures for the Yukawa couplings, one based on a permutation symmetry and the other on the Universal Strength of Yukawa couplings hypothesis (USY). In USY, all Yukawa couplings have equal strength and the difference in the Yukawa structure lies in some complex phase. In both scenarios, all Yukawa couplings are of the same order of magnitude. Thus, the main features of the fermion hierarchies are explained through the RS geometrical mechanism, and not because some Yukawa coupling is extremely small. We find that the RS model is particularly appropriate to incorporate the suggested Yukawa configurations. Indeed, the RS geometrical mechanism of fermion locations along the extra dimension, combined with the two Yukawa scenarios, reproduces all the present experimental data on fermion masses and mixing angles. It is quite remarkable that in the USY case, only two complex phases of definite value +-Pi/2 are sufficient to generate the known neutrino mass differences, while at same time, permitting large leptonic mixing in agreement with experiment.Comment: 11 page

Persistence in higher dimensions : a finite size scaling study

We show that the persistence probability $P(t,L)$, in a coarsening system of linear size $L$ at a time $t$, has the finite size scaling form $P(t,L)\sim L^{-z\theta}f(\frac{t}{L^{z}})$ where $\theta$ is the persistence exponent and $z$ is the coarsening exponent. The scaling function $f(x)\sim x^{-\theta}$ for $x \ll 1$ and is constant for large $x$. The scaling form implies a fractal distribution of persistent sites with power-law spatial correlations. We study the scaling numerically for Glauber-Ising model at dimension $d = 1$ to 4 and extend the study to the diffusion problem. Our finite size scaling ansatz is satisfied in all these cases providing a good estimate of the exponent $\theta$.Comment: 4 pages in RevTeX with 6 figures. To appear in Phys. Rev.