Information Content in Data Sets for a Nucleated-Polymerization Model

We illustrate the use of tools (asymptotic theories of standard error quantification using appropriate statistical models, bootstrapping, model comparison techniques) in addition to sensitivity that may be employed to determine the information content in data sets. We do this in the context of recent models [23] for nucleated polymerization in proteins, about which very little is known regarding the underlying mechanisms; thus the methodology we develop here may be of great help to experimentalists

Shape mode analysis exposes movement patterns in biology: flagella and flatworms as case studies

We illustrate shape mode analysis as a simple, yet powerful technique to concisely describe complex biological shapes and their dynamics. We characterize undulatory bending waves of beating flagella and reconstruct a limit cycle of flagellar oscillations, paying particular attention to the periodicity of angular data. As a second example, we analyze non-convex boundary outlines of gliding flatworms, which allows us to expose stereotypic body postures that can be related to two different locomotion mechanisms. Further, shape mode analysis based on principal component analysis allows to discriminate different flatworm species, despite large motion-associated shape variability. Thus, complex shape dynamics is characterized by a small number of shape scores that change in time. We present this method using descriptive examples, explaining abstract mathematics in a graphic way.Comment: 20 pages, 6 figures, accepted for publication in PLoS On

Polariton lasing in high-quality Selenide-based micropillars in the strong coupling regime

We have designed and fabricated all-epitaxial ZnSe-based optical micropillars exhibiting the strong coupling regime between the excitonic transition and the confined optical cavity modes. At cryogenic temperatures, under non-resonant pulsed optical excitation, we demonstrate single transverse mode polariton lasing operation in the micropillars. Owing to the high quality factors of these microstructures, the lasing threshold remains low even in micropillars of the smallest diameter. We show that this feature can be traced back to a sidewall roughness grain size below 3 nm, and to suppressed in-plane polariton escape.Comment: 5 pages, 3 figure

Substrate rigidity deforms and polarizes active gels

We present a continuum model of the coupling between cells and substrate that accounts for some of the observed substrate-stiffness dependence of cell properties. The cell is modeled as an elastic active gel, adapting recently developed continuum theories of active viscoelastic fluids. The coupling to the substrate enters as a boundary condition that relates the cell's deformation field to local stress gradients. In the presence of activity, the coupling to the substrate yields spatially inhomogeneous contractile stresses and deformations in the cell and can enhance polarization, breaking the cell's front-rear symmetry.Comment: 6 pages, 4 figures, EPL forma

Self-synchronization and dissipation-induced threshold in collective atomic recoil lasing

Networks of globally coupled oscillators exhibit phase transitions from incoherent to coherent states. Atoms interacting with the counterpropagating modes of a unidirectionally pumped high-finesse ring cavity form such a globally coupled network. The coupling mechanism is provided by collective atomic recoil lasing, i.e., cooperative Bragg scattering of laser light at an atomic density grating, which is self-induced by the laser light. Under the rule of an additional friction force, the atomic ensemble is expected to undergo a phase transition to a state of synchronized atomic motion. We present the experimental investigation of this phase transition by studying the threshold behavior of this lasing process

Significance of HbA1c levels in diabetic retinopathy extremes in South Africa

Background. Diabetic retinopathy (DR) is one of the leading causes of blindness in sub-Saharan Africa and globally, placing a huge disease burden on patients and the public health system. DR varies in severity from non-proliferative to proliferative DR (PDR).Objectives. Using a monitor of medium- to long-term blood glucose control, to determine the association between glycated haemoglobin (HbA1c) levels in patients with PDR and those with no DR.Methods. A prospective, cross-sectional study was conducted at McCord Provincial Eye Hospital in Durban, South Africa. We studied only patients diagnosed with diabetes mellitus (DM) for >1 year who had either PDR or no DR, and compared their HbA1c levels. Patients with non-proliferative DR were not included.Results. Patients with PDR had significantly higher HbA1c levels than those with no DR. Patients with type 1 DM had higher HbA1c levels than patients with type 2 DM in both the PDR and no-DR groups. Older patients (>70 years) had lower HbA1c levels than younger patients. Gender, race and duration of diabetes had no influence on HbA1c levels.Conclusions. PDR was associated with higher HbA1c in type 2 DM in all races and age groups and was independent of duration of disease. The trend was the same for type 1 DM, but significance could not be reached, probably because of small numbers in this subset of patients

Significance of HbA1c levels in diabetic retinopathy extremes in South Africa

Background. Diabetic retinopathy (DR) is one of the leading causes of blindness in sub-Saharan Africa and globally, placing a huge disease burden on patients and the public health system. DR varies in severity from non-proliferative to proliferative DR (PDR). Objectives. Using a monitor of medium-to long-term blood glucose control, to determine the association between glycated haemoglobin (HbA1c) levels in patients with PDR and those with no DR. Methods. A prospective, cross-sectional study was conducted at McCord Provincial Eye Hospital in Durban, South Africa. We studied only patients diagnosed with diabetes mellitus (DM) for >1 year who had either PDR or no DR, and compared their HbA1c levels. Patients with non-proliferative DR were not included. Results. Patients with PDR had significantly higher HbA1c levels than those with no DR. Patients with type 1 DM had higher HbA1c levels than patients with type 2 DM in both the PDR and no-DR groups. Older patients (>70 years) had lower HbA1c levels than younger patients. Gender, race and duration of diabetes had no influence on HbA1c levels. Conclusions. PDR was associated with higher HbA1c in type 2 DM in all races and age groups and was independent of duration of disease. The trend was the same for type 1 DM, but significance could not be reached, probably because of small numbers in this subset of patients

Systemic criticality

With high certainty, extreme weather events will intensify in their impact within the next 10 years due to climate change-induced increases in hazard probability of occurrence and simultaneous increases in socio-economic vulnerability. Data from previous mega-disasters show that losses from disruptions of critical services surpass the value of direct damages in the exposed areas because critical infrastructures [CI] are increasingly (inter-) dependent. Local events may have global impacts. Systemic criticality, which describes the relevance of a critical infrastructure due to its positioning within the system, needs to be addressed to reduce the likelihood of cascading effects. This paper presents novel approaches to operationalise and assess systemic criticality. Firstly, the paper introduces systemic cascade potential as a measurement of systemic criticality. It takes the relevance of a sector and the relevance of its interdependencies into account to generate a relative value of systemic importance for a CI sector. Secondly, an exemplary sectoral assessment of the road network allows reflecting the spatial manifestation of the first level of cascading effects. It analyses the impact of traffic interruptions on the accessibility of critical facilities to point out the systemically most critical segments of the municipal road network. To further operationalise the spatial dimension of criticality, a normative assertion determining the worthiness of protection of system components is required. A nationwide spatial flood protection plan incorporates this aspect in Germany for the first time. Its formal approval process was initiated in February 2020

High-order space-time finite element schemes for acoustic and viscodynamic wave equations with temporal decoupling

Copyright @ 2014 The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.We revisit a method originally introduced by Werder et al. (in Comput. Methods Appl. Mech. Engrg., 190:6685–6708, 2001) for temporally discontinuous Galerkin FEMs applied to a parabolic partial differential equation. In that approach, block systems arise because of the coupling of the spatial systems through inner products of the temporal basis functions. If the spatial finite element space is of dimension D and polynomials of degree r are used in time, the block system has dimension (r + 1)D and is usually regarded as being too large when r > 1. Werder et al. found that the space-time coupling matrices are diagonalizable over inline image for r ⩽100, and this means that the time-coupled computations within a time step can actually be decoupled. By using either continuous Galerkin or spectral element methods in space, we apply this DG-in-time methodology, for the first time, to second-order wave equations including elastodynamics with and without Kelvin–Voigt and Maxwell–Zener viscoelasticity. An example set of numerical results is given to demonstrate the favourable effect on error and computational work of the moderately high-order (up to degree 7) temporal and spatio-temporal approximations, and we also touch on an application of this method to an ambitious problem related to the diagnosis of coronary artery disease