Ising Spin Glasses on Wheatstone-Bridge Hierarchical Lattices

Nearest-neighbor-interaction Ising spin glasses are studied on three different hierarchical lattices, all of them belonging to the Wheatstone-Bridge family. It is shown that the spin-glass lower critical dimension in these lattices should be greater than 2.32. Finite-temperature spin-glass phases are found for a lattice of fractal dimension $D \approx 3.58$ (whose unit cell is obtained from a simple construction of a part of the cubic lattice), as well as for a lattice of fractal dimension close to five.Comment: Accepted for publication in Physics Letters

Direct thermal conductance measurements on suspended monocrystalline nanostructures

We describe and demonstrate a new class of devices that enable direct thermal conductance measurements on monocrystalline nanostructures. These are possible through our newly developed techniques for three-dimensional, successive surface nanomachining of GaAs-based heterostructures. Our methods allow the patterning of complex devices comprising electrically insulating, mesoscopic thermal conductors with separate, thermal transducers in situ. Intimate thermal contact between these elements is provided by their epitaxial registry. Low-temperature thermal conductance measurements indicate that phonon boundary scattering in these initial nanometer is scale structures is partially specular. These devices offer promise for ultrasensitive bolometry and calorimetry

User's Guide for ERB 7 SEFDT. Volume 1: User's Guide. Volume 2: Quality Control Report, Year 1

The Nimbus-7 ERB SEFDT Data User's Guide is presented. The guide consists of four subsections which describe: (1) the scope of the data User's Guide; (2) the background on Nimbus-7 Spacecraft and the ERB experiment; (3) the SEFDT data product and processing scenario; and (4) other related products and documents

Contact Changes of Sheared Systems: Scaling, Correlations, and Mechanisms

We probe the onset and effect of contact changes in 2D soft harmonic particle packings which are sheared quasistatically under controlled strain. First, we show that in the majority of cases, the first contact changes correspond to the creation or breaking of contacts on a single particle, with contact breaking overwhelmingly likely for low pressures and/or small systems, and contact making and breaking equally likely for large pressures and in the thermodynamic limit. The statistics of the corresponding strains are near-Poissonian. The mean characteristic strains exhibit scaling with the number of particles N and pressure P, and reveal the existence of finite size effects akin to those seen for linear response quantities. Second, we show that linear response accurately predicts the strains of the first contact changes, which allows us to study the scaling of the characteristic strains of making and breaking contacts separately. Both of these show finite size scaling, and we formulate scaling arguments that are consistent with the observed behavior. Third, we probe the effect of the first contact change on the shear modulus G, and show in detail how the variation of G remains smooth and bounded in the large system size limit: even though contact changes occur then at vanishingly small strains, their cumulative effect, even at a fixed value of the strain, are limited, so that effectively, linear response remains well-defined. Fourth, we explore multiple contact changes under shear, and find strong and surprising correlations between alternating making and breaking events. Fifth, we show that by making a link with extremal statistics, our data is consistent with a very slow crossover to self averaging with system size, so that the thermodynamic limit is reached much more slowly than expected based on finite size scaling of elastic quantities or contact breaking strains

Force balance in canonical ensembles of static granular packings

We investigate the role of local force balance in the transition from a microcanonical ensemble of static granular packings, characterized by an invariant stress, to a canonical ensemble. Packings in two dimensions admit a reciprocal tiling, and a collective effect of force balance is that the area of this tiling is also invariant in a microcanonical ensemble. We present analytical relations between stress, tiling area and tiling area fluctuations, and show that a canonical ensemble can be characterized by an intensive thermodynamic parameter conjugate to one or the other. We test the equivalence of different ensembles through the first canonical simulations of the force network ensemble, a model system.Comment: 9 pages, 9 figures, submitted to JSTA

Microorganisms and Common Ophthalmic Diseases

The human eye is in constant contact to environmental conditions that increase its likelihood in being exposed to a multitude of pathogens. Studies have revealed that the normal microbial flora found around the ocular area contribute to the well-being of ocular health as they play a critical role in inhibiting the proliferation of other pathogenic species and maintaining the homeostatic balance. However an imbalance in this status quo may lead to diseases including dry eye syndrome, meibomian gland dysfunction (MGD), blepharitis, rosacea, allergies, keratitis, conjunctivitis and immunological conditions such as mucous membrane pemphigoid and Sjogren’s syndrome. Thus, it is important to investigate and understand the role of various microorganisms that lead to these ocular diseases, and this knowledge may lead to better future treatments. This review focuses on recent advances and insights of pathogens and related ocular diseases which can help the audience further understand the etiology and the control of these disease

Geometry and Topology of Escape I: Epistrophes

We consider a dynamical system given by an area-preserving map on a two-dimensional phase plane and consider a one-dimensional line of initial conditions within this plane. We record the number of iterates it takes a trajectory to escape from a bounded region of the plane as a function along the line of initial conditions, forming an ``escape-time plot''. For a chaotic system, this plot is in general not a smooth function, but rather has many singularities at which the escape time is infinite; these singularities form a complicated fractal set. In this article we prove the existence of regular repeated sequences, called ``epistrophes'', which occur at all levels of resolution within the escape-time plot. (The word ``epistrophe'' comes from rhetoric and means ``a repeated ending following a variable beginning''.) The epistrophes give the escape-time plot a certain self-similarity, called ``epistrophic'' self-similarity, which need not imply either strict or asymptotic self-similarity.Comment: 15 pages, 9 figures, to appear in Chaos, first of two paper

Group versus one‐to‐one multi‐component lifestyle interventions for weight management: a systematic review and meta-analysis of randomised controlled trials

Background Multi-component lifestyle interventions that incorporate diet, physical activity and behaviour change are effective for weight management. However, it is not clear whether delivery in a group or one-to-one format influences weight loss efficacy. The present study aimed to systematically review the evidence of the effectiveness of group compared to one-to-one multi-component lifestyle interventions for weight management. Methods MEDLINE, EMBASE, CINAHL, CENTRAL and ISRCTN databases were searched from inception up to February 2020 for randomised controlled trials comparing group versus one-to-one multi-component lifestyle interventions for weight loss in adults with a body mass index ≥ 25 kg m–2. The primary outcome was weight loss (kg) at 12 months and the secondary outcome was attainment of ≥5% weight loss at 12 months. Risk of bias was assessed using the Cochrane Risk of Bias Tool. Meta-analysis used random effects and estimated risk ratios and continuous inverse variance methods. Heterogeneity was investigated using I2 statistics and sensitivity analyses. Results Seven randomised controlled trials with 2576 participants were included. Group interventions were favoured over one-to-one interventions for weight loss at 12 months (−1.9 kg, 95% confidence interval = −1.3 to −2.6; I2 = 99%). Participants of group interventions were more likely to attain ≥5% weight loss at 12 months relative to one-to-one interventions (relative risk = 1.58, 95% confidence interval = 1.25–2.00; I2 = 60%). Conclusions Group multi-component lifestyle interventions are superior for weight loss compared to one-to-one interventions with respect to adult weight management. Further research is required to determine whether specific components of group interventions can explain the superiority of weight loss outcomes in group interventions