Which Sectors of a Modern Economy are most Central?

We analyze input-output matrices for a wide set of countries as weighted directed networks. These graphs contain only 47 nodes, but they are almost fully connected and many have nodes with strong self-loops. We apply two measures: random walk centrality and one based on count-betweenness. Our findings are intuitive. For example, in Luxembourg the most central sector is “Finance and Insurance” and the analog in Germany is “Wholesale and Retail Trade” or “Motor Vehicles”, according to the measure. Rankings of sectoral centrality vary by country. Some sectors are often highly central, while others never are. Hierarchical clustering reveals geographical proximity and similar development status.

Rectification effects in coherent transport through single molecules

A minimal model for coherent transport through a donor/acceptor molecular junction is presented. The two donor and acceptor sites are described by single levels energetically separated by an intramolecular tunnel barrier. In the limit of strong coupling to the electrodes a current rectification for different bias voltage polarities occurs. Contacts with recent experiments of molecular rectification are also given.Comment: 10 pages, 4 figure

System Level Synthesis Beyond Finite Impulse Response Using Approximation by Simple Poles

Optimal linear feedback control design is valuable but challenging. The system level synthesis approach uses a reparameterization to expand the class of problems that can be solved using convex reformulations, among other benefits. However, to solve system level synthesis problems prior work relies on finite impulse response approximations that lead to deadbeat control, and that can experience infeasibility and increased suboptimality, especially in systems with large separation of time scales. This work develops a new technique by combining system level synthesis with a new approximation based on simple poles. The result is a new design method which does not result in deadbeat control, is convex and tractable, always feasible, can incorporate prior knowledge, and works well for systems with large separation of time scales. A general suboptimality result is provided which bounds the approximation error based on the geometry of the pole selection. The bound is then specialized to a particularly interesting pole selection to obtain a non-asymptotic convergence rate. An example demonstrates superior performance of the method.Comment: 25 page

Critical Casimir forces in colloidal suspensions on chemically patterned surfaces

We investigate the behavior of colloidal particles immersed in a binary liquid mixture of water and 2,6-lutidine in the presence of a chemically patterned substrate. Close to the critical point of the mixture, the particles are subjected to critical Casimir interactions with force components normal and parallel to the surface. Because the strength and sign of these interactions can be tuned by variations in the surface properties and the mixtures temperature, critical Casimir forces allow the formation of highly ordered monolayers but also extend the use of colloids as model systems.Comment: 4 papges, 4 figures, accepted at Phys. Rev. Let

Distributed and Constrained H2 \mathcal{H}_2 Control Design via System Level Synthesis and Dual Consensus ADMM

Design of optimal distributed linear feedback controllers to achieve a desired aggregate behavior, while simultaneously satisfying state and input constraints, is a challenging but important problem in many applications, including future power systems with weather-dependent renewable generation. System level synthesis is a recent technique which has been used to reparametrize the optimal control problem as a convex program. However, prior work is restricted to a centralized control design, which lacks robustness to communication failures and disturbances, has high computational cost and does not preserve data privacy of local controllers. The main contribution of this work is to develop a distributed solution to the previous optimal control problem, while incorporating agent-specific and globally coupled constraints in a non-conservative manner. To achieve this, it is first shown that the dual of this problem is a distributed consensus problem. Then, an algorithm is developed based on the alternating direction method of multipliers to solve the dual while recovering a primal solution, and a convergence certificate is provided. Finally, the method's performance is demonstrated on a test case of control design for distributed energy resources that collectively provide stability services to the power grid

Effective spin-wave action for ordered Heisenberg antiferromagnets in a magnetic field

We derive the effective long-wavelength Euclidean action for the antiferromagnetic spin-waves of ordered quantum antiferromagnets subject to a uniform magnetic field. We point out that the magnetic field dependence of the spin-wave dispersion predicted by the usual O(3)-quantum nonlinear sigma model disagrees with spin-wave theory. We argue that the nonlinear sigma model does not take into account all relevant spin-wave interactions and derive a modified effective action for the long-wavelength spin-waves which contains an additional quartic interaction. At zero temperature the corresponding vertex is relevant in the renormalization group sense below three dimensions.Comment: 4 pages, 1 eps figure; proceedings of the symposium on "Spin- and charge-correlations in molecule-based materials", October 2005, Koenigstein (Taunus), German

The impact of concomitant Sjogren’s disease on rheumatoid arthritis disease activity:a systematic review and meta-analysis

Objectives: Rheumatoid arthritis (RA) and Sjögren’s Syndrome (SjS) frequently co-exist but the consequence for RA disease activity of having concomitant SjS (RA/SjS) is not well established. We conducted a systematic review and meta-analysis to investigate the impact of SjS on disease outcomes in individuals with RA. Methods: We searched Web of Science (Core Collection, FSTA, Medline), PubMed and Cochrane databases, without language restriction. Studies reporting RA disease activity scores, joint counts, visual analogue scales (VAS), disability and joint damage, and comparing RA and RA/SjS were selected. Outcomes reported in at least 3 studies in which the diagnosis of SjS fulfilled classification criteria underwent meta-analysis, using a random effects model where heterogeneity was detected.Results: The literature search identified 2991 articles and abstracts; 23 underwent full-text review and 16 were included. The studies included a total of 29722 patients (8614 with RA/SjS and 21108 with RA). Using studies eligible for meta-analysis (744 patients with RA/SjS and 4450 with RA), we found higher DAS-28 ESR scores (mean difference 0.50, 95% CI -0.008-1.006; p = 0.05), higher swollen joint count scores (mean difference 1.05, 95% CI 0.42-1.67; p = 0.001), and greater functional disability as measured by HAQ (mean difference 0.19, 95% CI 0.05-0.34; p=0.009) in RA/SjS compared to RA alone. Other outcome measures (tender joint count, fatigue VAS) showed a numerical trend towards higher scores in RA/SjS but were not statistically significant. Conclusion: RA/SjS patients appear to have higher disease activity and more functional disability than patients with RA alone. The aetiology and clinical implications of this are unclear and warrant further investigation.<br/

Concomitant Sjögren’s disease as a biomarker for treatment effectiveness in rheumatoid arthritis:results from the Swiss clinical quality management cohort

Objective: To investigate the clinical phenotype and treatment response in patients with rheumatoid arthritis (RA) with and without concomitant Sjögren’s disease (SjD). Methods: In this observational cohort study, patients with RA from the Swiss Clinical Quality Management in Rheumatic Diseases registry were categorised according to the presence or absence of SjD. To assess treatment effectiveness, drug retention of tumor necrosis factor-α-inhibitors (TNFi) was compared to other mode of action (OMA) biologics and Janus kinase-inhibitors (JAKi) in RA patients with and without SjD. Adjusted hazard ratios (HR) for time to drug discontinuation were compared in crude and adjusted Cox proportional regression models for potential confounders.Results: We identified 5974 patients without and 337 patients with concomitant SjD. Patients with SjD were more likely to be female, to have a positive rheumatoid factor, higher disease activity scores, and erosive bone damage. For treatment response, a total of 6781 treatment courses were analysed. After one year, patients with concomitant SjD were less likely to reach DAS28 remission with all three treatment modalities. Patients with concomitant SjD had a higher hazard for stopping TNFi treatment (adjusted HR 1.3 [95% CI 1.07-1.6]; OMA HR 1.12 [0.91-1.37]; JAKi HR 0.97 [0.62-1.53]). When compared to TNFi, patients with concomitant SjD had a significantly lower hazard for stopping treatment with OMA (adjusted HR 0.62 [95% CI 0.46-0.84]) and JAKi (HR 0.52 [0.28-0.96]).Conclusion: RA patients with concomitant SjD reveal a severe RA phenotype, are less responsive to treatment, and more likely to fail TNFi. <br/

Results from the Randomized Controlled Multicenter German Algorithm Project 3 Trial

Background Treatment algorithms are considered as key to improve outcomes by enhancing the quality of care. This is the first randomized controlled study to evaluate the clinical effect of algorithm-guided treatment in inpatients with major depressive disorder. Methods Inpatients, aged 18 to 70 years with major depressive disorder from 10 German psychiatric departments were randomized to 5 different treatment arms (from 2000 to 2005), 3 of which were standardized stepwise drug treatment algorithms (ALGO). The fourth arm proposed medications and provided less specific recommendations based on a computerized documentation and expert system (CDES), the fifth arm received treatment as usual (TAU). ALGO included 3 different second-step strategies: lithium augmentation (ALGO LA), antidepressant dose-escalation (ALGO DE), and switch to a different antidepressant (ALGO SW). Time to remission (21-item Hamilton Depression Rating Scale ≤9) was the primary outcome. Results Time to remission was significantly shorter for ALGO DE (n=91) compared with both TAU (n=84) (HR=1.67; P=.014) and CDES (n=79) (HR=1.59; P=.031) and ALGO SW (n=89) compared with both TAU (HR=1.64; P=.018) and CDES (HR=1.56; P=.038). For both ALGO LA (n=86) and ALGO DE, fewer antidepressant medications were needed to achieve remission than for CDES or TAU (P<.001). Remission rates at discharge differed across groups; ALGO DE had the highest (89.2%) and TAU the lowest rates (66.2%). Conclusions A highly structured algorithm-guided treatment is associated with shorter times and fewer medication changes to achieve remission with depressed inpatients than treatment as usual or computerized medication choice guidance

Entanglement-enhanced probing of a delicate material system

Quantum metrology uses entanglement and other quantum effects to improve the sensitivity of demanding measurements. Probing of delicate systems demands high sensitivity from limited probe energy and has motivated the field's key benchmark-the standard quantum limit. Here we report the first entanglement-enhanced measurement of a delicate material system. We non-destructively probe an atomic spin ensemble by means of near-resonant Faraday rotation, a measurement that is limited by probe-induced scattering in quantum-memory and spin-squeezing applications. We use narrowband, atom-resonant NOON states to beat the standard quantum limit of sensitivity by more than five standard deviations, both on a per-photon and per-damage basis. This demonstrates quantum enhancement with fully realistic loss and noise, including variable-loss effects. The experiment opens the way to ultra-gentle probing of single atoms, single molecules, quantum gases and living cells.Comment: 7 pages, 8 figures; Nature Photonics, advance online publication, 16 December 201