Dynamical Mean Field Theory for the Bose-Hubbard Model

The dynamical mean field theory (DMFT), which is successful in the study of strongly correlated fermions, was recently extended to boson systems [Phys. Rev. B {\textbf 77}, 235106 (2008)]. In this paper, we employ the bosonic DMFT to study the Bose-Hubbard model which describes on-site interacting bosons in a lattice. Using exact diagonalization as the impurity solver, we get the DMFT solutions for the Green's function, the occupation density, as well as the condensate fraction on a Bethe lattice. Various phases are identified: the Mott insulator, the Bose-Einstein condensed (BEC) phase, and the normal phase. At finite temperatures, we obtain the crossover between the Mott-like regime and the normal phase, as well as the BEC-to-normal phase transition. Phase diagrams on the $\mu/U-\tilde{t}/U$ plane and on the $T/U-\tilde{t}/U$ plane are produced ($\tilde{t}$ is the scaled hopping amplitude). We compare our results with the previous ones, and discuss the implication of these results to experiments.Comment: 11 pages, 8 figure

Self-Healing Effects in OAM Beams Observed on a 28 GHz Experimental Link

In this paper we document for the first time some of the effects of self-healing, a property of orbital-angular-momentum (OAM) or vortex beams, as observed on a millimeter-wave experimental communications link in an outdoors line-of-sight (LOS) scenario. The OAM beams have a helical phase and polarization structure and have conical amplitude shape in the far field. The Poynting vectors of the OAM beams also possess helical structures, orthogonal to the corresponding helical phase-fronts. Due to such non-planar structure in the direction orthogonal to the beam axis, OAM beams are a subset of structured light beams. Such structured beams are known to possess self-healing properties when partially obstructed along their propagation axis, especially in their near fields, resulting in partial reconstruction of their structures at larger distances along their beam axis. Various theoretical rationales have been proposed to explain, model and experimentally verify the self-healing physical effects in structured optical beams, using various types of obstructions and experimental techniques. Based on these models, we hypothesize that any self-healing observed will be greater as the OAM order increases. Here we observe the self-healing effects for the first time in structured OAM radio beams, in terms of communication signals and channel parameters rather than beam structures. We capture the effects of partial near-field obstructions of OAM beams of different orders on the communications signals and provide a physical rationale to substantiate that the self-healing effect was observed to increase with the order of OAM, agreeing with our hypothesis.Comment: 9 pages, 10 figures, pending submission to IEEE Access journa

What are the current and projected future cost and health-related quality of life implications of scaling up cognitive stimulation therapy?

Objectives: Cognitive stimulation therapy (CST) is one of the few non-pharmacological interventions for people living with dementia shown to be effective and cost-effective. What are the current and future cost and health-related quality of life implications of scaling-up CST to eligible new cases of dementia in England? // Methods/design: Data from trials were combined with microsimulation and macrosimulation modelling to project future prevalence, needs and costs. Health and social costs, unpaid care costs and quality-adjusted life years (QALYs) were compared with and without scaling-up of CST and follow-on maintenance CST (MCST). // Results: Scaling-up group CST requires year-on-year increases in expenditure (mainly on staff), but these would be partially offset by reductions in health and care costs. Unpaid care costs would increase. Scaling-up MCST would also require additional expenditure, but without generating savings elsewhere. There would be improvements in general cognitive functioning and health-related quality of life, summarised in terms of QALY gains. Cost per QALY for CST alone would increase from £12,596 in 2015 to £19,573 by 2040, which is below the threshold for cost-effectiveness used by the National Institute for Health and Care Excellence (NICE). Cost per QALY for CST and MCST combined would grow from £19,883 in 2015 to £30,906 by 2040, making it less likely to be recommended by NICE on cost-effectiveness grounds. // Conclusions: Scaling-up CST England for people with incident dementia can improve lives in an affordable, cost-effective manner. Adding MCST also improves health-related quality of life, but the economic evidence is less compelling

What are the current and projected future cost and health-related quality of life implications of scaling up cognitive stimulation therapy?

Objectives: Cognitive stimulation therapy (CST) is one of the few non-pharmacological interventions for people living with dementia shown to be effective and cost-effective. What are the current and future cost and health-related quality of life implications of scaling-up CST to eligible new cases of dementia in England? Methods/design: Data from trials were combined with microsimulation and macrosimulation modelling to project future prevalence, needs and costs. Health and social costs, unpaid care costs and quality-adjusted life years (QALYs) were compared with and without scaling-up of CST and follow-on maintenance CST (MCST). Results: Scaling-up group CST requires year-on-year increases in expenditure (mainly on staff), but these would be partially offset by reductions in health and care costs. Unpaid care costs would increase. Scaling-up MCST would also require additional expenditure, but without generating savings elsewhere. There would be improvements in general cognitive functioning and health-related quality of life, summarised in terms of QALY gains. Cost per QALY for CST alone would increase from £12,596 in 2015 to £19,573 by 2040, which is below the threshold for cost-effectiveness used by the National Institute for Health and Care Excellence (NICE). Cost per QALY for CST and MCST combined would grow from £19,883 in 2015 to £30,906 by 2040, making it less likely to be recommended by NICE on cost-effectiveness grounds. Conclusions: Scaling-up CST England for people with incident dementia can improve lives in an affordable, cost-effective manner. Adding MCST also improves health-related quality of life, but the economic evidence is less compelling

Escherichia coli TatA and TatB Proteins Have N-out, C-in Topology in Intact Cells

The twin arginine protein transport (Tat) system translocates folded proteins across the cytoplasmic membrane of prokaryotes and the thylakoid membrane of chloroplasts. In Escherichia coli, TatA, TatB, and TatC are essential components of the machinery. A complex of TatB and TatC acts as the substrate receptor, whereas TatA is proposed to form the Tat transport channel. TatA and TatB are related proteins that comprise an N-terminal transmembrane helix and an adjacent amphipathic helix. Previous studies addressing the topological organization of TatA have given conflicting results. In this study, we have addressed the topological arrangement of TatA and TatB in intact cells by labeling of engineered cysteine residues with the membrane-impermeable thiol reagent methoxypolyethylene glycol maleimide. Our results show that TatA and TatB share an N-out, C-in topology, with no evidence that the amphipathic helices of either protein are exposed at the periplasmic side of the membrane. We further show that the N-out, C-in topology of TatA is fixed and is not affected by the absence of other Tat components or by the overproduction of a Tat substrate. These data indicate that topological reorganization of TatA is unlikely to accompany Tat-dependent protein transport

The effect of salient stimuli on neural oscillations, isometric force, and their coupling.

Survival in a suddenly-changing environment requires animals not only to detect salient stimuli, but also to promptly respond to them by initiating or revising ongoing motor processes. We recently discovered that the large vertex brain potentials elicited by sudden supramodal stimuli are strongly coupled with a multiphasic modulation of isometric force, a phenomenon that we named cortico-muscular resonance (CMR). Here, we extend our investigation of the CMR to the time-frequency domain. We show that (i) both somatosensory and auditory stimuli evoke a number of phase-locked and non-phase-locked modulations of EEG spectral power. Remarkably, (ii) some of these phase-locked and non-phase-locked modulations are also present in the Force spectral power. Finally, (iii) EEG and Force time-frequency responses are correlated in two distinct regions of the power spectrum. An early, low-frequency region (∼4 Hz) reflects the previously-described coupling between the phase-locked EEG vertex potential and force modulations. A late, higher-frequency region (beta-band, ∼20 Hz) reflects a second coupling between the non-phase-locked increase of power observed in both EEG and Force. In both time-frequency regions, coupling was maximal over the sensorimotor cortex contralateral to the hand exerting the force, suggesting an effect of the stimuli on the tonic corticospinal drive. Thus, stimulus-induced CMR occurs across at least two different types of cortical activities, whose functional significance in relation to the motor system should be investigated further. We propose that these different types of corticomuscular coupling are important to alter motor behaviour in response to salient environmental events

Refining the accuracy of validated target identification through coding variant fine-mapping in type 2 diabetes.

We aggregated coding variant data for 81,412 type 2 diabetes cases and 370,832 controls of diverse ancestry, identifying 40 coding variant association signals (P < 2.2 × 10-7); of these, 16 map outside known risk-associated loci. We make two important observations. First, only five of these signals are driven by low-frequency variants: even for these, effect sizes are modest (odds ratio ≤1.29). Second, when we used large-scale genome-wide association data to fine-map the associated variants in their regional context, accounting for the global enrichment of complex trait associations in coding sequence, compelling evidence for coding variant causality was obtained for only 16 signals. At 13 others, the associated coding variants clearly represent 'false leads' with potential to generate erroneous mechanistic inference. Coding variant associations offer a direct route to biological insight for complex diseases and identification of validated therapeutic targets; however, appropriate mechanistic inference requires careful specification of their causal contribution to disease predisposition

The north-south tilt in the Australian Height Datum is explained by the ocean’s mean dynamic topography

Using geodetic and oceanographic data, we show that the apparent north-south slope between the Australian Height Datum (AHD) and the geoid is caused almost completely by the ocean’s time-mean dynamic topography (MDT). This is because the AHD was constrained to zero height at local mean sea level at multiple tide gauges around the Australian continent. Using MDT models and corrected leveling data, almost all of the apparent north-south slope can be removed from the AHD. An auxiliary observation is that a satellite-only MDT model based on only around one year of GOCE data generates results commensurate with geodetic, oceanographic and combined MDT models