61 research outputs found

    Active Galactic Nuclei at the Crossroads of Astrophysics

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    Over the last five decades, AGN studies have produced a number of spectacular examples of synergies and multifaceted approaches in astrophysics. The field of AGN research now spans the entire spectral range and covers more than twelve orders of magnitude in the spatial and temporal domains. The next generation of astrophysical facilities will open up new possibilities for AGN studies, especially in the areas of high-resolution and high-fidelity imaging and spectroscopy of nuclear regions in the X-ray, optical, and radio bands. These studies will address in detail a number of critical issues in AGN research such as processes in the immediate vicinity of supermassive black holes, physical conditions of broad-line and narrow-line regions, formation and evolution of accretion disks and relativistic outflows, and the connection between nuclear activity and galaxy evolution.Comment: 16 pages, 5 figures; review contribution; "Exploring the Cosmic Frontier: Astrophysical Instruments for the 21st Century", ESO Astrophysical Symposia Serie

    'Concrete freedom' : C.L.R. James on culture and black politics

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    This article aims to provide a synoptic account of the cultural writings of the West Indian intellectual and activist C.L.R. James. I aim to make a case for greater recognition of his work among cultural sociologists. I go on to show how James’ original, historicising account of cultural forms relates closely to his wider political interventions including, specifically, his ground-breaking discussion of mid-twentieth century black politics in America

    Fitting the integrated Spectral Energy Distributions of Galaxies

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    Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details ofdust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (sedfitting.org), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics & Space Scienc

    Analysis of fish assemblages in sectors along a salinity gradient based on species, families and functional groups

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    Rising rural body-mass index is the main driver of the global obesity epidemic in adults

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    Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3�6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55 of the global rise in mean BMI from 1985 to 2017�and more than 80 in some low- and middle-income regions�was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing�and in some countries reversal�of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories. © 2019, The Author(s)

    Rich microbial communities inhabit water treatment biofilters and are differentially affected by filter type and sampling depth

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    Factors affecting microbial diversity (richness) and community structure in biofilter columns were investigated. At a pilot filtration plant, granular activated carbon (GAC), anthracite and sand-based filters were used to treat stormwater from an urban catchment. After 12 weeks operation, sand media filters clogged (hydraulic conductivity declining by 90%) and all filters were destructively sampled. All biofilters had similar levels of polysaccharide in the surface layer, however only the sand columns clogged. This clogging may have been due to a combination of polysaccharide and small particle size, the development of a sand-specific microbial community, or other biogeochemical interactions. DNA fingerprinting was used to show that bacterial, archaeal and eukaryotic communities were present in all filter types and at all sampling depths (to 45 cm). The bacterial community was far richer (Margalefs index, d, 1.5-2) than the other groups. This was consistent across filter types and sampling depths. The structure of the bacteria and archaea communities in sand filters differed to those in GAC and anthracite filters (P<0.05). In contrast, eukaryotic communities were similar in surface biofilm layers, irrespective of filter type. As such, physicochemical properties of filters differentially influence the microbial community. Furthermore, we have established that archaea are distributed throughout biofilters; the role of these microorganisms in water treatment and filter function, particularly clogging, requires attention

    Implementing lifestyle change interventions to prevent type 2 diabetes in US medicaid programs: Cost effectiveness, and cost, health, and health equity impact.

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    Background Lifestyle change interventions (LCI) for prevention of type 2 diabetes are covered by Medicare, but rarely by US Medicaid programs that constitute the largest public payer system in the USA. We estimate the long-term health and economic implications of implementing LCIs in state Medicaid programs. Methods We compared LCIs modeled after the intervention of the Diabetes Prevention Program versus routine care advice using a decision analytic simulation model and best available data from representative surveys, cohort studies, Medicaid claims data, and the published literature. Target population were non-disability-based adult Medicaid beneficiaries aged 19-64 years at high risk for type 2 diabetes (BMI &gt;= 25 kg/m(2)and HbA1c &gt;= 5.7% or fasting plasma glucose &gt;= 110 mg/dl) from eight study states (Alabama, California, Connecticut, Florida, Iowa, Illinois, New York, Oklahoma) that represent around 50% of the US Medicaid population. Incremental cost-effectiveness ratios (ICERs) measured in cost per quality-adjusted life years (QALYs) gained, and population cost and health impact were modeled from a healthcare system perspective and a narrow Medicaid perspective. Results In the eight selected study states, 1.9 million or 18% of non-disability-based adult Medicaid beneficiaries would belong to the eligible high-risk target population - 66% of them Hispanics or non-Hispanic black. In the base-case analysis, the aggregated 5- and 10-year ICERs are US226k/QALYandUS226 k/QALY and US34 k/QALY; over 25 years, the intervention dominates routine care. The 5-, 10-, and 25-year probabilities that the ICERs are below US50k(US50 k (US100 k)/QALY are 6% (15%), 59% (82%) and 96% (100%). From a healthcare system perspective, initial program investments of US800perpersonwouldbeoffsetafter13yearsandtranslatetoUS800 per person would be offset after 13 years and translate to US548 of savings after 25 years. With a 20% LCI uptake in eligible beneficiaries, this would translate to upfront costs of US300million,prevent260thousandyearsofdiabetesandsaveUS300 million, prevent 260 thousand years of diabetes and save US205 million over a 25-year time horizon. Cost savings from a narrow Medicaid perspective would be much smaller. Minorities and low-income groups would over-proportionally benefit from LCIs in Medicaid, but the impact on population health and health equity would be marginal. Conclusions In the long-term, investments in LCIs for Medicaid beneficiaries are likely to improve health and to decrease healthcare expenditures. However, population health and health equity impact would be low and healthcare expenditure savings from a narrow Medicaid perspective would be much smaller than from a healthcare system perspective

    Measurement and verification of zero energy settlements: Lessons learned from four pilot cases in Europe

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    Measurement and verification (M&amp;V) has become necessary for ensuring intended design performance. Currently, M&amp;V procedures and calculation methods exist for the assessment of Energy Conservation Measures (ECM) for existing buildings, with a focus on reliable baseline model creation and savings estimation, as well as for reducing the computation time, uncertainties, and M&amp;V costs. There is limited application of rigorous M&amp;V procedures in the design, delivery and operation of low/zero energy dwellings and settlements. In the present paper, M&amp;V for four pilot net-zero energy settlements has been designed and implemented. The M&amp;V has been planned, incorporating guidance from existing protocols, linked to the project development phases, and populated with lessons learned through implementation. The resulting framework demonstrates that M&amp;V is not strictly linked to the operational phase of a project but is rather an integral part of the project management and development. Under this scope, M&amp;V is an integrated, iterative process that is accompanied by quality control in every step. Quality control is a significant component of the M&amp;V, and the proposed quality control procedures can support the preparation and implementation of automated M&amp;V. The proposed framework can be useful to project managers for integrating M&amp;V into the project management and development process and explicitly aligning it with the rest of the design and construction procedures. © 2020 by the authors. Licensee MDPI, Basel, Switzerland
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