The story behind the plot: About the propositionality of visually presented argumentation

When we define argumentation as a communicative activity aimed at convincing a reasona-ble critic of the acceptability of a standpoint by putting forward information justifying or refuting this standpoint, it is clear that elements of this information can be brought forward in other than verbal modes. An important question is then whether visually presented information needs to be translatable into a set of propositions as traditional definitions require. The answer is: not always

Oligon-coated contact lens case study: The efficacy of oligodynamic iontophoresis as a contact lens disinfection system as determined by FDA stand-alone protocol

Prototype contact lens cases have been prepared which are coated with an Oligon antimicrobial silicone formulation. The Oligon silicone coating incorporates a conductive additive, silver and platinum powder to set up an electrochemical system, that when contacted by chloride ions found in physiological saline, releases silver ions into the surrounding aqueous medium. Silver ions have been reported in the literature to be a potent antimicrobial agent, showing effectiveness against both gram-positive and gram-negative bacteria as well as yeasts and molds. This study was designed to study the effectiveness of Oligon coated contact lens cases against FDA (Food and Drug Administration) approved Stand Alone protocol for disinfecting contact lenses for the following organisms: Psuedomonas aeruginosa, Serratia marcenscens, Staphylococcus aureus, Candida albicans, and Fusarium solani. The results of the study conclude that the Oligon cases do not meet the 8 hour FDA stand alone criteria for any of the organisms tested, but with modification, may be an exciting new frontier for the future of contact lens disinfection

Early Adversity and Late Life Employment History—A Sequence Analysis Based on SHARE

Numerous studies have linked poor socioeconomic circumstances during working life with early retirement. Few studies, however, have summarized entire patterns of employment histories and tested their links to social position at earlier stages of the life course. Therefore, this article summarizes types of late life employment histories and tests their associations with adversity both during childhood and early adulthood. We use data from the Survey of Health, Ageing and Retirement in Europe (SHARE) with retrospective life history data on 5,857 older men and women across 14 countries. Employment histories are studied with annual information on the employment situation between ages 50 and 70. To summarize employment histories we apply sequence analysis and group histories into 8 clusters with similar histories. Most of these clusters are dominated by full-time employees, with retirement before, at or after age 60. Additionally, we find clusters that are dominated by self-employment and comparatively late retirement. The remaining clusters are marked by part-time work, continuous domestic work, or discontinuous histories that include unemployment before retirement. Results of multinomial regressions (accounting for country affiliation and adjusted for potential confounders) show that early adversity is linked to full-time employment ending in retirement at age 60 or earlier and to discontinuous histories (in the case of women), but not to histories of self-employment. In sum, we find that histories of employees with early retirement and discontinuous histories are part of larger trajectories of disadvantage throughout the life course, supporting the idea of cumulative disadvantage in life course research

Late Life Employment Histories and Their Association With Work and Family Formation During Adulthood: A Sequence Analysis Based on ELSA

Objectives: To extend research on workforce participation beyond age 50 by describing entire employment histories in later life and testing their links to prior life course conditions. Methods: We use data from the English Longitudinal Study of Ageing, with retrospective information on employment histories between age 50 and 70 for 1,103 men and 1,195 women (n = 2,298). We apply sequence analysis and group respondents into eight clusters with similar histories. Using multinomial regressions, we then test their links to labor market participation, partnership, and parenthood histories during early (age 20–34) and mid-adulthood (age 35–49). Results: Three clusters include histories dominated by full-time employees but with varying age of retirement (before, at, and after age 60). One cluster is dominated by self-employment with comparatively later retirement. Remaining clusters include part-time work (retirement around age 60 or no retirement), continuous domestic work (mostly women), or other forms of nonemployment. Those who had strong attachments to the labor market during adulthood are more likely to have histories of full-time work up until and beyond age 60, especially men. Parenthood in early adulthood is related to later retirement (for men only). Continued domestic work was not linked to parenthood. Partnered women tend to work part-time or do domestic work. The findings remain consistent after adjusting for birth cohort, childhood adversity, life course health, and occupational position. Discussion: Policies aimed at increasing the proportion of older workers not only need to address later stages of the life course but also early and mid-adulthood

Performance analysis of linear optical amplifiers in dynamic WDM systems

We demonstrate the performance of linear optical amplifiers (LOAs) in a dynamic and reconfigurable wavelength-division-multiplexing (WDM) system. Eight WDM channels, each channel running at 10 Gb/s, are transmitted through two cascaded LOAs. Power transient immune add-drop capability is demonstrated by switching four of the eight channels at rates of 10-100 kHz without affecting the bit-error-rate (BER) or eye pattern. The same WDM system trial using erbium-doped fiber amplifiers instead of LOAs shows identical BER performance for the eight-channel case, but deteriorated eye patterns and bit error penalties for the channel ADD-DROP configuration

The optical flare

Optical observationd now present considerable information on the flare process. It is always associated with filaments and with simplification of existing magnetic connections, and it arises from the emergence and expansion of new flux. The optical flare divides into impulsive phase, with multiple flashes along the neutral line, and thermal phase, with two-ribbon expansion. The former bears some resemblance to tearing mode phenomena. The appearance of loops in emission requires very high densities in those phenomena. The ratios of the hydrogen lines, the excitation of HeII 4686, and the relation of vertical to horizontal structure all remain to be explained

On the Quasi-Periodic Oscillations of Magnetars

We study torsional Alfv\'en oscillations of magnetars, i.e., neutron stars with a strong magnetic field. We consider the poloidal and toroidal components of the magnetic field and a wide range of equilibrium stellar models. We use a new coordinate system (X,Y), where $X=\sqrt{a_1} \sin \theta$, $Y=\sqrt{a_1}\cos \theta$ and $a_1$ is the radial component of the magnetic field. In this coordinate system, the 1+2-dimensional evolution equation describing the quasi-periodic oscillations, QPOs, see Sotani et al. (2007), is reduced to a 1+1-dimensional equation, where the perturbations propagate only along the Y-axis. We solve the 1+1-dimensional equation for different boundary conditions and open magnetic field lines, i.e., magnetic field lines that reach the surface and there match up with the exterior dipole magnetic field, as well as closed magnetic lines, i.e., magnetic lines that never reach the stellar surface. For the open field lines, we find two families of QPOs frequencies; a family of "lower" QPOs frequencies which is located near the X-axis and a family of "upper" frequencies located near the Y-axis. According to Levin (2007), the fundamental frequencies of these two families can be interpreted as the turning points of a continuous spectrum. We find that the upper frequencies are constant multiples of the lower frequencies with a constant equaling 2n+1. For the closed lines, the corresponding factor is n+1 . By these relations, we can explain both the lower and the higher observed frequencies in SGR 1806-20 and SGR 1900+14.Comment: 8 pages, 7 figure

Erbium in crystal silicon: Optical activation, excitation, and concentration limits

7 pags.; 7 figs.The optical activation, excitation, and concentration limits of erbium in crystal Si are studied. Preamorphized surface layers of Czochralski-grown (Cz) Si(100), containing 1.7×1018 O/cm3, were implanted with 250 keV Er at fluences in the range 8×1011-8×10 14 cm-2. After thermal solid-phase epitaxy of the Er-doped amorphous layers at 600°C, Er is trapped in the crystal at concentrations ranging from 3×1016 to 7×1019 Er/cm 3, as measured by secondary-ion-mass spectrometry. Photoluminescence spectra taken at 77 K show the characteristic Er3+ intra-4f luminescence at 1.54 ¿m. Photoluminescence excitation spectroscopy shows that Er is excited through a photocarrier-mediated process. Rapid thermal annealing at 1000°C for 15 s increases the luminescence intensity, mainly due to an increase in minority-carrier lifetime, which enhances the excitation efficiency. Luminescent Er forms clusters with oxygen: the maximum Er concentration that can be optically activated is determined by the O content, and is (3±1)×1017 Er/cm3 in Cz-Si. The internal quantum efficiency for electrical excitation of Er in Cz-Si is larger than 3×10-6. © 1995 American Institute of Physics.This work is part of the research program of the Foundation for Fundamental Research on Matter (FOM) and was made possible by financial support from the Dutch Organization for the Advancement of Pure Research @IWO), the Netherlands Technology Foundation (STW), and the IC Technology Program (IOP Electra-Optics) of the Ministry of Economic Affairs. R.S. acknowIedges financial support from CSIC, Spain.Peer Reviewe

Direct simulation of ion beam induced stressing and amorphization of silicon

Using molecular dynamics (MD) simulation, we investigate the mechanical response of silicon to high dose ion-irradiation. We employ a realistic and efficient model to directly simulate ion beam induced amorphization. Structural properties of the amorphized sample are compared with experimental data and results of other simulation studies. We find the behavior of the irradiated material is related to the rate at which it can relax. Depending upon the ability to deform, we observe either the generation of a high compressive stress and subsequent expansion of the material, or generation of tensile stress and densification. We note that statistical material properties, such as radial distribution functions are not sufficient to differentiate between different densities of amorphous samples. For any reasonable deformation rate, we observe an expansion of the target upon amorphization in agreement with experimental observations. This is in contrast to simulations of quenching which usually result in denser structures relative to crystalline Si. We conclude that although there is substantial agreement between experimental measurements and most simulation results, the amorphous structures being investigated may have fundamental differences; the difference in density can be attributed to local defects within the amorphous network. Finally we show that annealing simulations of our amorphized samples can lead to a reduction of high energy local defects without a large scale rearrangement of the amorphous network. This supports the proposal that defects in amorphous silicon are analogous to those in crystalline silicon.Comment: 13 pages, 12 figure

Nonlinear force-free magnetic field extrapolations: comparison of the Grad-Rubin and Wheatland-Sturrock-Roumeliotis algorithm

We compare the performance of two alternative algorithms which aim to construct a force-free magnetic field given suitable boundary conditions. For this comparison, we have implemented both algorithms on the same finite element grid which uses Whitney forms to describe the fields within the grid cells. The additional use of conjugate gradient and multigrid iterations result in quite effective codes. The Grad-Rubin and Wheatland-Sturrock-Roumeliotis algorithms both perform well for the reconstruction of a known analytic force-free field. For more arbitrary boundary conditions the Wheatland-Sturrock-Roumeliotis approach has some difficulties because it requires overdetermined boundary information which may include inconsistencies. The Grad-Rubin code on the other hand loses convergence for strong current densities. For the example we have investigated, however, the maximum possible current density seems to be not far from the limit beyond which a force free field cannot exist anymore for a given normal magnetic field intensity on the boundary.Comment: 21 pages, 13 figure