Characterizing the many-body localization transition through the entanglement spectrum

We numerically explore the many body localization (MBL) transition through the lens of the {\it entanglement spectrum}. While a direct transition from localization to thermalization is believed to obtain in the thermodynamic limit (the exact details of which remain an open problem), in finite system sizes there exists an intermediate `quantum critical' regime. Previous numerical investigations have explored the crossover from thermalization to criticality, and have used this to place a numerical {\it lower} bound on the critical disorder strength for MBL. A careful analysis of the {\it high energy} part of the entanglement spectrum (which contains universal information about the critical point) allows us to make the first ever observation in exact numerics of the crossover from criticality to MBL and hence to place a numerical {\it upper bound} on the critical disorder strength for MBL.Comment: 4 pages+appendi

Hospital quality reports in Germany: patient and physician opinion of the reported quality indicators

<p>Abstract</p> <p>Background</p> <p>Starting in 2005, Germany's health law required hospital quality reports to be published every two years by all acute care hospitals. The reports were intended to help patients and physicians make informed choices of hospitals. However, while establishing the quality indicators that form the content of the reports, the information needs of the target groups were not explicitly taken into account. Therefore, the aim of our study was to determine patient and physician opinion of the relevance of the reported quality indicators for choosing or referring to a hospital.</p> <p>Methods</p> <p>Convenience samples of 50 patients and 50 physicians were asked to rate the understandability (patients), suitability (physicians) and relevance (both groups) of a set of 29 quality indicators. The set was drawn from the reports (24 indicators) and supplemented by five indicators commonly used in hospital quality reports. We analysed the differences in patient and physician ratings of relevance of all indicators by applying descriptive statistics, t-tests and Wilcoxon tests.</p> <p>Results</p> <p>Only three indicators were considered not understandable by the interviewed patients and unsuitable by the interviewed physicians. The patients rated 19 indicators as highly or very relevant, whereas the physicians chose 15 indicators. The most relevant indicator for the patients was "qualification of doctors", and for the physicians "volume of specified surgical procedures". Patient and physician rankings of individual indicators differed for 25 indicators. However, three groups of indicators could be differentiated, in which the relevance ratings of patients and physicians differed only within the groups. Four of the five indicators that were added to the existing set of reported indicators ranked in the first or second group ("kindness of staff", "patient satisfaction", "recommendation", and "distance to place of living").</p> <p>Conclusion</p> <p>Most of the content of Germany's hospital quality reports seems to be useful for patients and physicians and influence their choice of hospitals. However, the target groups revealed that approximately one third of the indicators (mostly hospital structural characteristics), were not useful and hence could have been omitted from the reports. To enhance the usefulness of the reports, indicators on patient experiences should be added.</p

Line of continuous phase transitions in a three dimensional U(1) model with 1/r^2 current-current interactions

We study a lattice model of interacting loops in three dimensions with a $1/r^2$ interaction. Using Monte Carlo, we find that the phase diagram contains a line of second-order phase transitions between a phase where the loops are gapped and a phase where they proliferate. The correlation length exponent and critical conductivity vary continuously along this line. Our model is exactly self-dual at a special point on the critical line, which allows us to calculate the critical conductivity exactly at this point.Comment: 6 pages, 6 figure

A urinary Common Rejection Module (uCRM) score for non-invasive kidney transplant monitoring.

A Common Rejection Module (CRM) consisting of 11 genes expressed in allograft biopsies was previously reported to serve as a biomarker for acute rejection (AR), correlate with the extent of graft injury, and predict future allograft damage. We investigated the use of this gene panel on the urine cell pellet of kidney transplant patients. Urinary cell sediments collected from patients with biopsy-confirmed acute rejection, borderline AR (bAR), BK virus nephropathy (BKVN), and stable kidney grafts with normal protocol biopsies (STA) were analyzed for expression of these 11 genes using quantitative polymerase chain reaction (qPCR). We assessed these 11 CRM genes for their abundance, autocorrelation, and individual expression levels. Expression of 10/11 genes were elevated in AR when compared to STA. Psmb9 and Cxcl10could classify AR versus STA as accurately as the 11-gene model (sensitivity = 93.6%, specificity = 97.6%). A uCRM score, based on the geometric mean of the expression levels, could distinguish AR from STA with high accuracy (AUC = 0.9886) and correlated specifically with histologic measures of tubulitis and interstitial inflammation rather than tubular atrophy, glomerulosclerosis, intimal proliferation, tubular vacuolization or acute glomerulitis. This urine gene expression-based score may enable the non-invasive and quantitative monitoring of AR

Exact Results for the Bipartite Entanglement Entropy of the AKLT spin-1 chain

We study the entanglement between two domains of a spin-1 AKLT chain subject to open boundary conditions. In this case the ground-state manifold is four-fold degenerate. We summarize known results and present additional exact analytical results for the von Neumann entanglement entropy, as a function of both the size of the domains and the total system size for {\it all} four degenerate ground-states. In the large $l,L$ limit the entanglement entropy approaches $\ln(2)$ and $2\ln(2)$ for the $S^z_T=\pm 1$ and $S^z_T=0$ states, respectively. In all cases, it is found that this constant is approached exponentially fast defining a length scale $\xi=1/\ln(3)$ equal to the known bulk correlation length.Comment: 11 pages, 3 figure

Type 2 Endoleak With or Without Intervention and Survival After Endovascular Aneurysm Repair

Objective: The aims of the present study were to examine the impact of type 2 endoleaks (T2EL) on overall survival and to determine the need for secondary intervention after endovascular aneurysm repair (EVAR). Methods: A multicentre retrospective cohort study in the Netherlands was conducted among patients with an infrarenal abdominal aortic aneurysm (AAA) who underwent EVAR between 2007 and 2012. The primary endpoint was overall survival for patients with (T2EL+) or without (T2EL-) a T2EL. Secondary endpoints were sac growth, AAA rupture, and secondary intervention. Kaplan–Meier survival and multivariable Cox regression analysis were used. Results: A total of 2 018 patients were included. The median follow up was 62.1 (range 0.1 – 146.2) months. No difference in overall survival was found between T2EL+ (n = 388) and T2EL- patients (n = 1630) (p =.54). The overall survival estimates at five and 10 years were 73.3%/69.4% and 45.9%/44.1% for T2EL+/T2EL- patients, respectively. Eighty-five of 388 (21.9%) T2EL+ patients underwent a secondary intervention. There was no difference in overall survival between T2EL+ patients who underwent a secondary intervention and those who were treated conservatively (p =.081). Sac growth was observed in 89 T2EL+ patients and 44/89 patients (49.4%) underwent a secondary intervention. In 41/44 cases (93.1%), sac growth was still observed after the intervention, but was left untreated. Aneurysm rupture occurred in 4/388 T2EL patients. In Cox regression analysis, higher age, ASA classification, and maximum iliac diameter were significantly associated with worse overall survival. Conclusion: No difference in overall survival was found between T2EL+ and T2EL- patients. Also, patients who underwent a secondary intervention did not have better survival compared with those who did not undergo a secondary intervention. This study reinforces the need for conservative treatment of an isolated T2EL and the importance of a prospective study to determine possible advantages of the intervention

Comprehensive embryo testing. Experts opinions regarding future directions: an expert panel study on comprehensive embryo testing

What do scientists in the field of preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS) consider to be the future direction of comprehensive embryo testing? Although there are many biological and technical limitations, as well as uncertainties regarding the meaning of genetic variation, comprehensive embryo testing will impact the IVF/PGD practice and a timely ethical reflection is needed. Comprehensive testing using microarrays is currently being introduced in the context of PGD and PGS, and it is to be expected that whole-genome sequencing will also follow. Current ethical and empirical sociological research on embryo testing focuses on PGD as it is practiced now. However, empirical research and systematic reflection regarding the impact of comprehensive techniques for embryo testing is missing. In order to understand the potential of this technology and to be able to adequately foresee its implications, we held an expert panel with seven pioneers in PGD. We conducted an expert panel in October 2011 with seven PGD pioneers from Belgium, The Netherlands, Germany and the UK. Participants expected the use of comprehensive techniques in the context of PGD. However, the introduction of these techniques in embryo testing requires timely ethical reflection as it involves a shift from choosing an embryo without a particular genetic disease (i.e. PGD) or most likely to result in a successful pregnancy (i.e. PGS) to choosing the best embryo based on a much wider set of criteria. Such ethical reflection should take account of current technical and biological limitations and also of current uncertainties with regard to the meaning of genetic variance. However, ethicists should also not be afraid to look into the future. There was a general agreement that embryo testing will be increasingly preceded by comprehensive preconception screening, thus enabling smart combinations of genetic testing. The group was composed of seven participants from four Western Europe countries. As willingness to participate in this study may be connected with expectations regarding the pace and direction of future developments, selection bias cannot be excluded. The introduction of comprehensive screening techniques in embryo testing calls for further ethical reflection that is grounded in empirical work. Specifically, there is a need for studies querying the opinions of infertile couples undergoing IVF/PGS regarding the desirability of embryo screening beyond aneuploidy. This research was supported by the CSG, Centre for Society and Life Sciences (project number: 70.1.074). The authors declare no conflict of interest. N/A

Evidence for a topological "exciton Fermi sea" in bilayer graphene

The quantum Hall physics of bilayer graphene is extremely rich due to the interplay between a layer degree of freedom and delicate fractional states. Recent experiments show that when an electric field perpendicular to the bilayer causes Landau levels of opposing layers to cross in energy, a even-denominator Hall plateau can coexist with a finite density of inter-layer excitons. We present theoretical and numerical evidence that this observation is due to a new phase of matter - a Fermi sea of topological excitons