Galaxy formation in the Planck cosmology - II. Star-formation histories and post-processing magnitude reconstruction

We adapt the L-Galaxies semi-analytic model to follow the star-formation histories (SFH) of galaxies -- by which we mean a record of the formation time and metallicities of the stars that are present in each galaxy at a given time. We use these to construct stellar spectra in post-processing, which offers large efficiency savings and allows user-defined spectral bands and dust models to be applied to data stored in the Millennium data repository. We contrast model SFHs from the Millennium Simulation with observed ones from the VESPA algorithm as applied to the SDSS-7 catalogue. The overall agreement is good, with both simulated and SDSS galaxies showing a steeper SFH with increased stellar mass. The SFHs of blue and red galaxies, however, show poor agreement between data and simulations, which may indicate that the termination of star formation is too abrupt in the models. The mean star-formation rate (SFR) of model galaxies is well-defined and is accurately modelled by a double power law at all redshifts: SFR proportional to $1/(x^{-1.39}+x^{1.33})$, where $x=(t_a-t)/3.0\,$Gyr, $t$ is the age of the stars and $t_a$ is the loopback time to the onset of galaxy formation; above a redshift of unity, this is well approximated by a gamma function: SFR proportional to $x^{1.5}e^{-x}$, where $x=(t_a-t)/2.0\,$Gyr. Individual galaxies, however, show a wide dispersion about this mean. When split by mass, the SFR peaks earlier for high-mass galaxies than for lower-mass ones, and we interpret this downsizing as a mass-dependence in the evolution of the quenched fraction: the SFHs of star-forming galaxies show only a weak mass dependence.Comment: Accepted version of the paper, to appear in MNRAS. Compared to the original version, contains more detail on the post-processing of magnitudes, including a table of rms magnitude errors. SFHs available on Millennium database http://gavo.mpa-garching.mpg.de/MyMillennium

Superlattice Magnetophonon Resonances in Strongly Coupled InAs/GaSb Superlattices

We report an experimental study of miniband magnetoconduction in semiconducting InAs/GaSb superlattices. For samples with miniband widths below the longitudinal optical phonon energy we identify a new superlattice magnetophonon resonance (SLMPR) caused by resonant scattering of electrons across the mini-Brillouin zone. This new resonant feature arises directly from the drift velocity characteristics of the superlattice dispersion and total magnetic quantisation of the superlattice Landau level minibands.Comment: 9 pages, 8 figures, submitted to Phys. Rev.

Diluted Random Fields in Mixed Cyanide Crystals

A percolation argument and a dilute compressible random field Ising model are used to present a simple model for mixed cyanide crystals. The model reproduces quantitatively several features of the phase diagrams altough some crude approximations are made. In particular critical thresholds x_c at which ferroelastic first order transitions disappear, are calculated. Moreover, transitions are found to remain first order down to x_c for all mixtures except for bromine, for which the transition becomes continuous. All the results are in full agreement with experimental data.Comment: 8 pages, late

Two-stage aeration fermentation strategy to improve bioethanol production by scheffersomyces stipitis

Hardwood spent sulfite liquor (HSSL) is a by-product from pulp industry with a high concentration of pentose sugars, besides some hexoses suitable for bioethanol production by Scheffersomyces stipitis. The establishment of optimal aeration process conditions that results in specific microaerophilic conditions required by S. stipitis is the main challenge for ethanol production. The present study aimed to improve the ethanol production from HSSL by S. stipitis through a two-stage aeration fermentation. Experiments with controlled dissolved oxygen tension (DOT) in the first stage and oxygen restriction in the second stage were carried out. The best results were obtained with DOT control at 50% in the first stage, where the increase of oxygen availability provided faster growth and higher biomass yield, and no oxygen supply with an agitation rate of 250 rpm, in the second stage allowed a successful induction of ethanol production. Fermentation using 60% of HSSL (v/v) as substrate for S. stipitis provided a maximum specific growth rate of 0.07 h−1 , an ethanol productivity of 0.04 g L h−1 and an ethanol yield of 0.39 g g−1 , respectively. This work showed a successful two-stage aeration strategy as a promising aeration alternative for bioethanol production from HSSL by S. stipitis.publishe

Electrochemical vs antibacterial characterization of ZrCN-Ag coatings

Nowadays, antibacterial properties are becoming a viable feature to be introduced in biomaterials due to the possibility of modifying the materials' surface used in medical devices in a micro/nano metric scale. As a result, it is mandatory to understand the mechanisms of the antimicrobial agents currently used and their possible failures. In this work, the antibacterial activity of ZrCNAg films is studied, taking into consideration the ability of silver nanoparticles to be dissolved when embedded into a ceramic matrix. The study focuses on the silver release evaluated by glow discharge optical emission spectroscopy and the effect of the fluid composition on this release. The results revealed a very low silver release of the films, leading to non-antibacterial activity of such materials. The silver release was found to be dependent on the electrolyte composition. NaCl (8.9 g L? 1) showed the lowest spontaneously silver ionization, while introducing the sulfates in Hanks' balanced salt solution (HBSS) such ionization is increased; finally, the proteins incorporated to the (HBSS) showed a reduction of the silver release, which also explains the low ionization in the culture medium (tryptic soy broth) that contains high quantities of proteins.This research is partially sponsored by the FEDER funds through the program COMPETE - Programa Operacional Factores de Competitividade and by the Portuguese national funds through FCT-Fundacao para a Ciencia e a Tecnologia, under the projects ANTIMICROBCOAT - PTDC/CTM/102853/2008 and in the framework of the Strategic Projects PEST-C/FIS/UI607/2011, PEST-C/EME/UI0285/2011 and SFRH/BD/80947/2011.This work has also been supported by the Ministerio de Ciencia e Innovacion of Spain through the Consolider-Ingenio 2010 Programme (CSD2008-00023) and through project RyC2007-0026

Measurement of miniband parameters of a doped superlattice by photoluminescence in high magnetic fields

We have studied a 50/50\AA superlattice of GaAs/Al$_{0.21}$Ga$_{0.79}$As composition, modulation-doped with Si, to produce $n=1.4\times 10^{12}$ cm$^{-2}$ electrons per superlattice period. The modulation-doping was tailored to avoid the formation of Tamm states, and photoluminescence due to interband transitions from extended superlattice states was detected. By studying the effects of a quantizing magnetic field on the superlattice photoluminescence, the miniband energy width, the reduced effective mass of the electron-hole pair, and the band gap renormalization could be deduced.Comment: minor typing errors (minus sign in eq. (5)

Body image dissatisfaction and experimental pressure pain sensitivity in a cohort of 13-year-old adolescents

Objective: We aimed to quantify the associations between body image (dis)satisfaction and pressure pain thresholds in adolescents, using data from Generation XXI, a population-based cohort study in Portugal. Methods: We assessed 1785 13-year old adolescents cross-sectionally. Body image satisfaction was measured using the Children's Figure Rating Scale. Pain detection and tolerance thresholds were assessed using cuff pressure algometry. We quantified the associations between body image categories (satisfied, prefers slightly thinner, prefers much thinner, and prefers heavier) and pain detection and tolerance thresholds using linear and logistic regression for continuous and binary (odds of achieving the highest distribution quarter) outcomes, respectively. Models were adjusted to pubertal stage and body mass index. Results: Adolescents who desired a heavier silhouette had lower pressure pain tolerance thresholds when compared to those who were satisfied (linear regression coefficient: −3.95; 95% confidence interval: −6.68, −1.21), which was more precise in boys (−3.51; −7.17, −0.08). Those adolescents also had lower odds of achieving the highest quarter of pressure pain tolerance threshold (odds ratio: 0.66; 0.48, 0.90), especially girls (0.58; 0.35, 0.98). Adolescents who desired much thinner silhouettes had lower odds of achieving the highest quarter of pressure pain tolerance (0.68; 0.46, 1.00), and this was clearer in girls (0.66; 0.48, 0.90). Pain detection thresholds did not show robust associations with body image dissatisfaction. Conclusion: Our study suggests an association between satisfaction with one's silhouette and pain tolerance in adolescents from the general population, arguing for an integrated approach to the assessment of body image and pain sensitivity. © 2022 The AuthorsThis study was funded by the European Regional Development Fund (ERDF) , through COMPETE 2020 Operational Programme ‘Competitiveness and Internationalization’ together with national funding from the Foundation for Science and Technology (FCT) - Portuguese Ministry of Science, Technology and Higher Education - through the projects “ STEPACHE - The pediatric roots of amplified pain: from contextual influences to risk stratification ” ( POCI-01-0145-FEDER-029087 , PTDC/SAU-EPI/29087/2017 ), “ Appetite regulation and obesity in childhood: a comprehensive approach towards understanding genetic and behavioural influences ” ( PTDC/SAU-EPI/30334/2017/ POCI-01-0145- FEDER-030334) , and by the Epidemiology Research Unit - Instituto de Saúde Pública, Universidade do Porto (EPIUnit) ( POCI-01-0145-FEDER-006862 ; UID/DTP/04750/2019 ; LA/P/0064/2020 ), Administração Regional de Saúde Norte (Regional Department of the Portuguese Ministry of Health) and Calouste Gulbenkian Foundation . This work was also supported by a research grant from FOREUM Foundation for Research in Rheumatology (Career Research Grant). Funding sources were not involved in the design, conduct, analysis or writing of the present results

A life cycle stakeholder management framework for enhanced collaboration between stakeholders with competing interests

This is a postprint version of the Book Chapter. Information regarding the official publication is available from the link below - Copyright @ 2011 SpringerImplementation of a Life Cycle Sustainability Management (LCSM) strategy can involve significant challenges because of competing or conflicting objectives between stakeholders. These differences may, if not identified and managed, hinder successful adoption of sustainability initiatives. This article proposes a conceptual framework for stakeholder management in a LCSM context. The framework identifies the key sustainability stakeholder groups and suggests strategic ambiguity as a management tool to harness dysfunctional conflict into constructive collaboration. The framework is of practical value as it can be used as a guideline by managers who wish to improve collaboration with stakeholders along the supply chain. The article also fills a gap in the academic literature where there is only limited research on sustainability stakeholder management through strategic ambiguity