Integrated Stellar Populations: Confronting Photometry with Spectroscopy

We investigate the ability of spectroscopic techniques to yield realistic star formation histories (SFHs) for the bulges of spiral galaxies based on a comparison with their observed broadband colors. Full spectrum fitting to optical spectra indicates that recent (within ~1 Gyr) star formation activity can contribute significantly to the V-band flux, whilst accounting for only a minor fraction of the stellar mass budget which is made up primarily of old stars. Furthermore, recent implementations of stellar population (SP) models reveal that the inclusion of a more complete treatment of the thermally pulsating asymptotic giant branch (TP-AGB) phase to SP models greatly increases the NIR flux for SPs of ages 0.2-2 Gyr. Comparing the optical--NIR colors predicted from population synthesis fitting, using models which do not include all stages of the TP-AGB phase, to the observed colors reveals that observed optical--NIR colors are too red compared to the model predictions. However, when a 1 Gyr SP from models including a full treatment the TP-AGB phase is used, the observed and predicted colors are in good agreement. This has strong implications for the interpretation of stellar populations, dust content, and SFHs derived from colors alone.Comment: 6 pages, 6 figures, accepted for publication in the Astrophysical Journa

Ecological enhancement of coastal engineering structures: passive enhancement techniques

The rock type used in coastal engineering structures impacts biodiversity, but its effect has been understudied to date. We report here on whether different combinations of rock material and rock mass properties can improve habitat suitability and early phase ecological outcomes on coastal engineering structures. We examine two coastal engineering schemes that used different granites during construction. At site one, Shap granite boulders with a high number of cm-dm2 surface features (e.g. ledges) were deliberately positioned during construction (called passive enhancement), to a) maximise the provision of cm-dm scale intertidal habitat and b) determine which scale of habitat is best for ecological enhancement. At site two, Norwegian granite boulders were installed without passive enhancement, allowing for a direct comparison. Passive positioning of Shap granite boulders led to an increase in limpet (Patella vulgata, Linnaeus, 1758) abundance within two years but few limpets were recorded on the non-enhanced Norwegian granite. Positioning of boulder thus exerts a strong control on the mm and mm-dm scale geomorphic features present, with clear ecological benefits when suitable features are selected for and optimally positioned (i.e. passive enhancement) to maximise habitat features. An EcoRock scoring matrix was developed to aid in the selection of the most ecologically suitable rock materials for coastal engineering worldwide; this can help improve habitat provision on engineered structures in a rapidly warming world

Analyses of Special Hazards and Flooding Problems in Tropical Island Environments

Data and results summarized in this paper show that development of urban projects and design of flood control works in tropical island catchments must consider clear water flooding as well as special hazards such as landslides, flow bulking, high sediment concentrations, mud and debris flows and flow avulsions. The needs for and methods to estimate peak flows, event volumes and the potential extent and depths of flooding during severe storm events in urbanizing tropical environments are described

CHInclusion: Working toward a more inclusive HCI community

HCI has a growing body of work regarding important social and community issues, as well as various grassroots communities working to make CHI more international and inclusive. In this workshop, we will build on this work: first reflecting on the contemporary CHI climate, and then developing an actionable plan towards making CHI2019 and subsequent SIGCHI events and sister conferences more inclusive for all

The Formation and Evolution of Virgo Cluster Galaxies - I. Broadband Optical & Infrared Colours

We use a combination of deep optical (gri) and near-infrared (H) photometry to study the radially-resolved colours of a broad sample of 300 Virgo cluster galaxies. For most galaxy types, we find that the median g-H colour gradient is either flat (gas-poor giants and gas-rich dwarfs) or negative (i.e., colours become bluer with increasing radius; gas-poor dwarfs, spirals, and gas-poor peculiars). Later-type galaxies typically exhibit more negative gradients than early-types. Given the lack of a correlation between the central colours and axis ratios of Virgo spiral galaxies, we argue that dust likely plays a small role, if at all, in setting those colour gradients. We search for possible correlations between galaxy colour and photometric structure or environment and find that the Virgo galaxy colours become redder with increasing concentration, luminosity and surface brightness, while no dependence with cluster-centric radius or local galaxy density is detected (over a range of ~2 Mpc and ~3-16 Mpc^-2, respectively). However, the colours of gas-rich Virgo galaxies do correlate with neutral gas deficiency, such that these galaxies become redder with higher deficiencies. Comparisons with stellar population models suggest that these colour gradients arise principally from variations in stellar metallicity within these galaxies, while age variations only make a significant contribution to the colour gradients of Virgo irregulars. A detailed stellar population analysis based on this material is presented in Roediger et al (2011b; arXiv:1011.3511).Comment: 34 pages, 12 figures, 1 table, submitted to MNRAS; Paper II (arXiv:1011.3511) has also been update

Investigating Forest Photosynthetic Response to Elevated CO2 Using UAV-Based Measurements of Solar Induced Fluorescence

The response of ecosystems to increasing atmospheric CO2 will have significant, but still uncertain, impacts on the global carbon and water cycles. A lot of infounation has been gained from Free Air CO2 Enrichment (FACE) experiments, but the response of mature forest ecosystems remains a significant knowledge gap. One of the challenges in FACE studies is obtaining an integrated measure of canopy photosynthesis at the scale of the treatment ring. A new remote sensing approach for measuring photosynthetic activity is based on Solar Induced Fluorescence (SIF), which is emitted by plants during photosynthesis, and is closely linked to the rates and regulation of photosynthesis. We proposed that UAV-based SIF measurements, that enable the spectrometer field of view to be targeted to the treatment ring, provide a unique opportunity for investigating the dynamics of photosynthetic responses to elevated CO2. We have successfully tested this approach in a new FACE site, located in a mature oak forest in the UK. We flew a series of flights across the experiment arrays, collecting a number of spectra. We combined these with ground-based physiological and optical measurements, and see great promise in the use of UAV-based SIF measurements in FACE and other global change experiments.Peer reviewe

The Formation and Evolution of Virgo Cluster Galaxies - II. Stellar Populations

We use a combination of deep optical and near-infrared light profiles for a morphologically diverse sample of Virgo cluster galaxies to study the radially-resolved stellar populations of cluster galaxies over a wide range of galaxy structure. We find that, in the median, the age gradients of Virgo galaxies are either flat (lenticulars and Sa-Sb spirals) or positive (ellipticals, Sbc+Sc spirals, gas-rich dwarfs, and irregulars), while all galaxy types have a negative median metallicity gradient. Comparison of the galaxy stellar population diagnostics (age, metallicity, and gradients thereof) against structural and environmental parameters also reveals that the ages of gas-rich systems depend mainly on their atomic gas deficiencies. Conversely, the metallicities of Virgo gas-poor galaxies depend on their concentrations, luminosities, and surface brightnesses. The stellar population gradients of all Virgo galaxies exhibit no dependence on either their structure or environment. We interpret these stellar population data for Virgo galaxies in the context of popular formation and evolution scenarios, and suggest that gas-poor giants grew hierarchically (through dissipative starbursts), gas-poor dwarfs have descended from at least two different production channels (e.g., environmental transformation and merging), while spirals formed inside-out, but with star formation in the outskirts of a significant fraction of the population having been quenched due to ram pressure stripping. (Abridged)Comment: 54 pages, 16 figures, 3 tables, re-submitted to MNRAS (edited to reflect the referee's suggestions

Sex differences in pharmacological interventions and their effects on lifespan and healthspan outcomes: a systematic review

With an increasing aging population, the burden of age-related diseases magnifies. To alleviate this burden, geroprotection has been an area of intense research focus with the development of pharmacological interventions that target lifespan and/or healthspan. However, there are often sex differences, with compounds mostly tested in male animals. Given the importance of considering both sexes in preclinical research, this neglects potential benefits for the female population, as interventions tested in both sexes often show clear sexual dimorphisms in their biological responses. To further understand the prevalence of sex differences in pharmacological geroprotective intervention studies, we performed a systematic review of the literature according to the PRISMA guidelines. Seventy-two studies met our inclusion criteria and were classified into one of five subclasses: FDA-repurposed drugs, novel small molecules, probiotics, traditional Chinese medicine, and antioxidants, vitamins, or other dietary supplements. Interventions were analyzed for their effects on median and maximal lifespan and healthspan markers, including frailty, muscle function and coordination, cognitive function and learning, metabolism, and cancer. With our systematic review, we found that twenty-two out of sixty-four compounds tested were able to prolong both lifespan and healthspan measures. Focusing on the use of female and male mice, and on comparing their outcomes, we found that 40% of studies only used male mice or did not clarify the sex. Notably, of the 36% of pharmacologic interventions that did use both male and female mice, 73% of these studies showed sex-specific outcomes on healthspan and/or lifespan. These data highlight the importance of studying both sexes in the search for geroprotectors, as the biology of aging is not the same in male and female mice.Systematic Review Registration: [website], identifier [registration number]