Differentially Private Exponential Random Graphs

We propose methods to release and analyze synthetic graphs in order to protect privacy of individual relationships captured by the social network. Proposed techniques aim at fitting and estimating a wide class of exponential random graph models (ERGMs) in a differentially private manner, and thus offer rigorous privacy guarantees. More specifically, we use the randomized response mechanism to release networks under $\epsilon$-edge differential privacy. To maintain utility for statistical inference, treating the original graph as missing, we propose a way to use likelihood based inference and Markov chain Monte Carlo (MCMC) techniques to fit ERGMs to the produced synthetic networks. We demonstrate the usefulness of the proposed techniques on a real data example.Comment: minor edit

Survey of nucleon electromagnetic form factors

A dressed-quark core contribution to nucleon electromagnetic form factors is calculated. It is defined by the solution of a Poincare' covariant Faddeev equation in which dressed-quarks provide the elementary degree of freedom and correlations between them are expressed via diquarks. The nucleon-photon vertex involves a single parameter; i.e., a diquark charge radius. It is argued to be commensurate with the pion's charge radius. A comprehensive analysis and explanation of the form factors is built upon this foundation. A particular feature of the study is a separation of form factor contributions into those from different diagram types and correlation sectors, and subsequently a flavour separation for each of these. Amongst the extensive body of results that one could highlight are: r_1^{n,u}>r_1^{n,d}, owing to the presence of axial-vector quark-quark correlations; and for both the neutron and proton the ratio of Sachs electric and magnetic form factors possesses a zero.Comment: 43 pages, 17 figures, 12 tables, 5 appendice

Case report:peri-device leakage after percutaneous left atrial appendage occlusion: plug, clip, or amputate?

BACKGROUND: Although peri-device leakage is frequently observed after left atrial appendage occlusion (LAAO), there is no consensus on the optimal management strategy. It is unknown whether additional plugging should be preferred over surgical exclusion of the LAA, as experience with additional plugging is limited. CASE SUMMARY: In this case report, we demonstrate the clinical implications of additional plugging and surgical exclusion in a 65-year-old male patient with peri-device leakage and recurrent thromboembolic events. After the recurrence of paroxysmal atrial fibrillation (AF) and a transient ischaemic attack despite adequate anticoagulation, the patient was opted for re-do pulmonary vein isolation and LAAO with a Watchman device. Due to multiple ischaemic strokes and recurrent AF in combination with significant peri-device leakage, additional plugging with a second device was performed. Post-procedurally, the patient had another ischaemic stroke and persisting peri-device leakage was observed during follow-up. Due to progressive symptoms of AF and patient’s preference to discontinue DOAC, he underwent a Cox MAZE IV procedure, including amputation of the LAA with both devices. Within six months after surgery, the patient experienced two more ischaemic events. In the following two years, the patient remained free of any cerebrovascular accidents or recurrence of AF. DISCUSSION: Additional plugging of peri-device leakage is not always successful in stroke prevention. In combination with recurrent AF, progressive symptoms, contraindication for oral anticoagulation, and patient’s preference, surgical LAA exclusion could be preferred over additional plugging

Patterns of Disease Recurrence after SABR for Early Stage Non–Small-Cell Lung Cancer: Optimizing Follow-Up Schedules for Salvage Therapy

Introduction:Stereotactic ablative radiotherapy is a guideline-recommended treatment for early stage non–small-cell lung cancer. We report on incidence and salvage of local recurrences (LR) and second primary lung cancers (SPLC) in a large series of patients with long-term follow-up, to generate data for evidence-based follow-up regimens.Methods:We excluded all patients with double tumors, TNM-stages other than T1-T2N0M0, biologically effective dose less than 100 Gy10 and previous treatment for the index tumor from our institutional database. LR was defined as recurrence in/adjacent to the planning target volume. A diagnosis of SPLC was determined using criteria described by Martini et al.Results:The 855 patients included had a median follow-up of 52 months. Forty-six patients developed LR after a median of 22 months (range 7–87 months). Actuarial local control rates at 3 and 5 years were 92.4% and 90.9%, respectively. Fifty-four percent had isolated LR and 13% had LR in combination with regional recurrences. Ten patients underwent radical salvage treatment; surgery (N = 6), high-dose radiotherapy (N = 3), or chemoradiation (N = 1). Median overall survival following LR was 13 months, but it was 36 months in patients who underwent radical salvage. A SPLC was diagnosed in 79 patients, after a median interval of 34 months. Actuarial cumulative incidences of SPLC at 3 and 5 years were 11.7% and 16.7%, respectively. Radical salvage for SPLC was performed in 63 patients (80%).Conclusions:Both the timing of LR and persistent risk of SPLC serve as rationale for long-term follow-up using computed tomography scans in patients fit enough to undergo any radical treatment

Localization, Coulomb interactions and electrical heating in single-wall carbon nanotubes/polymer composites

Low field and high field transport properties of carbon nanotubes/polymer composites are investigated for different tube fractions. Above the percolation threshold f_c=0.33%, transport is due to hopping of localized charge carriers with a localization length xi=10-30 nm. Coulomb interactions associated with a soft gap Delta_CG=2.5 meV are present at low temperature close to f_c. We argue that it originates from the Coulomb charging energy effect which is partly screened by adjacent bundles. The high field conductivity is described within an electrical heating scheme. All the results suggest that using composites close to the percolation threshold may be a way to access intrinsic properties of the nanotubes by experiments at a macroscopic scale.Comment: 4 pages, 5 figures, Submitted to Phys. Rev.

Detection of endo-epicardial atrial low-voltage areas using unipolar and omnipolar voltage mapping

Background: Low-voltage areas (LVA) can be located exclusively at either the endocardium or epicardium. This has only been demonstrated for bipolar voltages, but the value of unipolar and omnipolar voltages recorded from either the endocardium and epicardium in predicting LVAs at the opposite layer remains unknown. The goal of this study was therefore to compare simultaneously recorded endo-epicardial unipolar and omnipolar potentials and to determine whether their voltage characteristics are predictive for opposite LVAs. Methods: Intra-operative simultaneous endo-epicardial mapping (256 electrodes, interelectrode distances 2 mm) was performed during sinus rhythm at the right atrium in 93 patients (67 ± 9 years, 73 male). Cliques of four electrodes (2 × 2 mm) were used to define maximal omnipolar (V(omni,max)) and unipolar (V(uni,max)) voltages. LVAs were defined as V(omni,max) ≤0.5 mV or V(uni,max) ≤1.0 mV. Results: The majority of both unipolar and omnipolar LVAs were located at only the endocardium (74.2% and 82.0% respectively) or epicardium (52.7% and 47.6% respectively). Of the endocardial unipolar LVAs, 25.8% were also located at the opposite layer and 47.3% vice-versa. In omnipolar LVAs, 18.0% of the endocardial LVAs were also located at the epicardium and 52.4% vice-versa. The combination of epicardial V(uni,max) and V(omni,max) was most accurate in identifying dual-layer LVAs (50.4%). Conclusion: Unipolar and omnipolar LVAs are frequently located exclusively at either the endocardium or epicardium. Endo-epicardial LVAs are most accurately identified using combined epicardial unipolar and omnipolar voltages. Therefore, a combined endo-epicardial unipolar and omnipolar mapping approach is favoured as it may be more indicative of possible arrhythmogenic substrates

Electronic Structure of Carbon Nanotube Ropes

We present a tight binding theory to analyze the motion of electrons between carbon nanotubes bundled into a carbon nanotube rope. The theory is developed starting from a description of the propagating Bloch waves on ideal tubes, and the effects of intertube motion are treated perturbatively in this basis. Expressions for the interwall tunneling amplitudes between states on neighboring tubes are derived which show the dependence on chiral angles and intratube crystal momenta. We find that conservation of crystal momentum along the tube direction suppresses interwall coherence in a carbon nanorope containing tubes with random chiralities. Numerical calculations are presented which indicate that electronic states in a rope are localized in the transverse direction with a coherence length corresponding to a tube diameter.Comment: 15 pages, 10 eps figure

Refining the predictions of supersymmetric CP-violating models: A top-down approach

We explore in detail the consequences of the CP-violating phases residing in the supersymmetric and soft SUSY breaking parameters in the approximation that family flavour mixings are ignored. We allow for non-universal boundary conditions and in such a consideration the model is described by twelve independent CP-violating phases and one angle which misaligns the vacuum expectation values (VEVs) of the Higgs scalars. We run two-loop renormalization group equations (RGEs), for all parameters involved, including phases, and we properly treat the minimization conditions using the one-loop effective potential with CP-violating phases included. We show that the two-loop running of phases may induce sizable effects for the electric dipole moments (EDMs) that are absent in the one-loop RGE analysis. Also important corrections to the EDMs are induced by the Higgs VEVs misalignment angle which are sizable in the large tanb region. Scanning the available parameter space we seek regions compatible with accelerator and cosmological data with emphasis on rapid neutralino annihilations through a Higgs resonance. It is shown that large CP-violating phases, as required in Baryogenesis scenarios, can be tuned to obtain agreement with WMAP3 cold dark matter constraints, EDMs and all available accelerator data, in extended regions of the parameter space which may be accessible to LHC.Comment: 41 pages, 22 eps figures. A reference added and a typo corrected; version to appear in JHE

The Minimally Tuned Minimal Supersymmetric Standard Model

The regions in the Minimal Supersymmetric Standard Model with the minimal amount of fine-tuning of electroweak symmetry breaking are presented for general messenger scale. No a priori relations among the soft supersymmetry breaking parameters are assumed and fine-tuning is minimized with respect to all the important parameters which affect electroweak symmetry breaking. The superpartner spectra in the minimally tuned region of parameter space are quite distinctive with large stop mixing at the low scale and negative squark soft masses at the high scale. The minimal amount of tuning increases enormously for a Higgs mass beyond roughly 120 GeV.Comment: 38 pages, including 2 appendices, 8 figure