Fitness distributions in exponentially growing asexual populations

We explore a mean-field model for the evolution of exponentially growing populations of mutating replicators. Motivated by recent in vitro experiments devised to analyze phenotypic properties of bacterial and viral populations subjected to serial population transfers, we allow our in silico individuals to undergo unrestricted growth before applying bottleneck events. Different dynamical regimes of our model can be mapped to different experimental situations. Numerical and analytical results for fitness distributions calculated at the statistically stationary states of the dynamics compare favorably with available experimental data. Our model and results provide a common framework to better understand populations evolving under different selection pressures.     

C*-Modular Vector States

Let be a C*-algebra and X a Hilbert C* -module. If is a projection, let be the p-sphere of X. For φ a state of with support p in and consider the modular vector state φ_x of given by The spheres provide fibrations

An improved Hardy-Sobolev inequality in W 1,p and its application to Schrödinger operators

In this paper we prove new Hardy-like inequalities with optimal potential singularities for functions in W^1,p(Ω), where Ω is either bounded or the whole space and also some extensions to arbitrary Riemannian manifolds. We also study the spectrum of perturbed Schr?dinger operators for perturbations which are just below the optimality threshold for the corresponding Hardy inequality.     

Resonant transmission of cold atoms through subwavelength apertures

Recently, it has been observed that transmission of light through subwavelength apertures, which is usually negligible, can be significantly enhanced when surface plasmons are resonantly excited. Here we introduce the idea that similar effects can be expected for cold atoms in structures supporting surface matter waves. We show that surface matter waves are possible in properly designed structures, and then we theoretically demonstrate 100% transmission of rubidium atoms through an array of slits much narrower than the de Broglie wavelength of the atoms. Our results open up the possibility of using surface matter waves to control the flow of neutral atoms.     

Transmission of light through a single rectangular hole

We show that a single rectangular hole in a metallic film exhibits transmission resonances that appear near the cutoff wavelength of the hole waveguide. For light polarized with the electric field pointing along the hole's short axis, it is shown that the normalized-to-area transmittance at resonance is proportional to the ratio between the long and short sides, and to the dielectric constant inside the hole. Importantly, this resonant transmission process is accompanied by a huge enhancement of the electric field at both entrance and exit interfaces of the hole.     

Gravitational Potentials of Triaxial Ellipsoids in Weyl Gravity

We present analytic expressions for the gravitational potentials associated with triaxial ellipsoids, spheroids, spheres and disks in Weyl gravity. The gravitational potentials of these configurations in Newtonian gravity, i.e. the potentials derived by integration of the Poisson equation Green's function 1/|r – r| over the volume of the configuration, are well known in the literature. Herein we present the results of the integration of |r – r|, the Green's function associated with the fourth order Laplacian ⁴ of Weyl gravity, over the volume of the configuration to obtain the resulting gravitational potentials within this specific theory. As an application of our calculations, we solve analytically Euler's equations pertaining to incompressible rotating fluids to show that, as in the case of Newtonian gravity, homogeneous prolate configurations are not allowed within Weyl gravity either.     

Simple model of compound waveguide structures used as fiber-optic sensors

In this work we present an application of a simple quasi-geometrical model to analyze the behavior of compound waveguide structures used as fiber-optic sensors. This theoretical model is based on the adjustment of the parameters of the structure from the experimental measures to predict the observed behavior of the device. It also takes into account the non-monocromaticity of the used source. In this way, it can be used as a design criterion for this kind of structures. It is applied to a refractive index fiber-optic sensor based on the excitation of surface plasmon in a metal layer by the light guided by a monomode fiber.     

Insight into the Thermal Ring‐Opening Polymerization of Phospha[1]ferrocenophanes

A mixture of cis/trans isomers of phospha[1]ferrocenophanes equipped with one iPr group at the α position to the bridging PhP moiety was prepared. Both isomers (cis‐ 4 and trans‐ 4 ) were obtained as racemates and could be separated so that their thermal properties were investigated individually. The molecular structure of cis‐ 4 was determined by single‐crystal X‐ray analysis showing a tilt angle α=26.35(8)°. Interconversion between both isomers occurred in the melt at elevated temperatures and revealed that the trans isomer is thermodynamically more stable. Structural and thermodynamic data was complemented by DFT calculations (B3PW91/6‐311+G(d,p) and B3PW91‐D3(BJ)/6‐311+G(d,p)). Performance of thermal ring‐opening polymerization (ROP) of trans‐ 4 at 230 °C gave polymers and cyclic oligomers. Gel permeation chromatography (GPC) of the sulfurized polymer resulted in a molecular weight of 62.5 kDa (M_w) and a polydispersity index of 1.39 (PDI). Mass spectrometric analysis of the oligomers showed the presence of cyclic species from dimers to heptamers. After sulfurization, preparative thin layer chromatography led to the separation of three isomeric dimers. Structural characterization of these dimers by single‐crystal X‐ray analysis led to the conclusion that the Fe?Cp bond breaks during the thermal ROP process. A mechanism similar to the known mechanism of the photolytic ROP of ferrocenophanes is proposed.     

Erratum: Explanation of Variability and Removal of Confounding Factors from Data through Optimal Transport

Due to a production error, the version of this article published in the print edition of the January 2018 issue had the wrong graphics for Figures 4.1 (p. 176), 4.3 (p. 179), 4.4 (p. 180), and 5.2 (p. 192). The correct figures are provided below. These corrected figures have been incorporated into the online version of the article.     

Parametric signal fitting by gaussian peak adjustment: A new multivariate curve resolution method for non-bilinear voltammetric measurements

A new methodology based on the fitting of signals to parametric functions is proposed for the multivariate curve resolution (MCR) analysis of overlapping and peak-shaped voltammetric signals which progressively get broader or narrower and move along the potential axis, thus causing a dramatic loss of linearity. The method is based on the least squares fitting of gaussian functions at both sides of the peaks by using adjustable parameters for the peak height, position and symmetry. It consists of several home-made programs written in Matlab environment, which are freely available as supplementary material of the present work. The application to the systems Zn(II)–oxalate, and to the phytochelatin PC₅ in a wide pH range provides excellent results as compared to these of more conventional linear methods, which raises good expectations about future application to electrochemical and even non-electrochemical data.