1,634 research outputs found

    SILC: a new Planck Internal Linear Combination CMB temperature map using directional wavelets

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    We present new clean maps of the CMB temperature anisotropies (as measured by Planck) constructed with a novel internal linear combination (ILC) algorithm using directional, scale-discretised wavelets --- Scale-discretised, directional wavelet ILC or SILC. Directional wavelets, when convolved with signals on the sphere, can separate the anisotropic filamentary structures which are characteristic of both the CMB and foregrounds. Extending previous component separation methods, which use the frequency, spatial and harmonic signatures of foregrounds to separate them from the cosmological background signal, SILC can additionally use morphological information in the foregrounds and CMB to better localise the cleaning algorithm. We test the method on Planck data and simulations, demonstrating consistency with existing component separation algorithms, and discuss how to optimise the use of morphological information by varying the number of directional wavelets as a function of spatial scale. We find that combining the use of directional and axisymmetric wavelets depending on scale could yield higher quality CMB temperature maps. Our results set the stage for the application of SILC to polarisation anisotropies through an extension to spin wavelets.Comment: 15 pages, 13 figures. Minor changes to match version published in MNRAS. Map products available at http://www.silc-cmb.or

    Spin-SILC: CMB polarisation component separation with spin wavelets

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    We present Spin-SILC, a new foreground component separation method that accurately extracts the cosmic microwave background (CMB) polarisation EE and BB modes from raw multifrequency Stokes QQ and UU measurements of the microwave sky. Spin-SILC is an internal linear combination method that uses spin wavelets to analyse the spin-2 polarisation signal P=Q+iUP = Q + iU. The wavelets are additionally directional (non-axisymmetric). This allows different morphologies of signals to be separated and therefore the cleaning algorithm is localised using an additional domain of information. The advantage of spin wavelets over standard scalar wavelets is to simultaneously and self-consistently probe scales and directions in the polarisation signal P=Q+iUP = Q + iU and in the underlying EE and BB modes, therefore providing the ability to perform component separation and EE-BB decomposition concurrently for the first time. We test Spin-SILC on full-mission Planck simulations and data and show the capacity to correctly recover the underlying cosmological EE and BB modes. We also demonstrate a strong consistency of our CMB maps with those derived from existing component separation methods. Spin-SILC can be combined with the pseudo- and pure EE-BB spin wavelet estimators presented in a companion paper to reliably extract the cosmological signal in the presence of complicated sky cuts and noise. Therefore, it will provide a computationally-efficient method to accurately extract the CMB EE and BB modes for future polarisation experiments.Comment: 13 pages, 9 figures. Minor changes to match version published in MNRAS. Map products available at http://www.silc-cmb.org. Companion paper: arXiv:1605.01414 "Wavelet reconstruction of pure E and B modes for CMB polarisation and cosmic shear analyses" (B. Leistedt et al.

    Effect fusion using model-based clustering

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    In social and economic studies many of the collected variables are measured on a nominal scale, often with a large number of categories. The definition of categories is usually not unambiguous and different classification schemes using either a finer or a coarser grid are possible. Categorisation has an impact when such a variable is included as covariate in a regression model: a too fine grid will result in imprecise estimates of the corresponding effects, whereas with a too coarse grid important effects will be missed, resulting in biased effect estimates and poor predictive performance. To achieve automatic grouping of levels with essentially the same effect, we adopt a Bayesian approach and specify the prior on the level effects as a location mixture of spiky normal components. Fusion of level effects is induced by a prior on the mixture weights which encourages empty components. Model-based clustering of the effects during MCMC sampling allows to simultaneously detect categories which have essentially the same effect size and identify variables with no effect at all. The properties of this approach are investigated in simulation studies. Finally, the method is applied to analyse effects of high-dimensional categorical predictors on income in Austria

    A Coordinated EU Minimum Wage Policy?

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    [Excerpt] Minimum wages exist in all EU member states, even if, as we shall see in this report, they are set up and established in very different ways. Minimum wages, in fact, can be considered as a cornerstone of the “European Social Model”. Yet, the on-going process of European integration has so far had very little to do with them. Wages are explicitly excluded from the competences of European institutions in the existing treaties, contrary to other areas of work and employment such as working time or health and safety. But in the context of increasing European integration, it seems at least plausible that sooner or later there would be some attempt of coordinating this important aspect of social policy across countries. As we will see in this report, the idea has been discussed at the European level several times since the EU was born, and it seems to be gaining momentum the context of the current economic crisis. Of course, the discussion is by no means settled, as many important European and national actors consider that this area should remain within the remit of national governments and according to national traditions and practices. It is certainly possible that wages, and minimum wages, would remain squarely at the level of national competence in the foreseeable future. Still, it seems like a worthwhile exercise (useful to the debate) to explore what kind of implications would be associated with such a coordination of European minimum wage policy. This is what we will try to do in this report. Without taking ourselves a position, we will try to provide arguments and facts that we hope can be useful in this debate. The report is organized in two big sections. In the first one, we will discuss the theoretical and policy considerations around a coordinated EU minimum wage policy. We will review the social sciences literature on the effects of minimum wages, present a broad picture of the current debates around the coordination of EU minimum wage policy and discuss the institutional difficulties that such a coordination would in our view have to face. In other words, that section will try to provide a balanced summary of the theoretical and policy arguments around this debate. The second big section will try to complement the arguments with some facts, by carrying out a “simple accounting exercise” to evaluate how many and what types of workers would be most affected by a hypothetical coordination of minimum wage policy in the different countries, using a baseline scenario of a single national wage floor of 60% of the median national wages and drawing from the two most recent EU-wide data sources on wages and income. Eurofound was established in 1975 with the mandate of contributing with knowledge to the planning and design of better living and working conditions in Europe. We hope that this report can at least contribute to the debate

    In-Work Poverty in the EU

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    [Excerpt] The working poor are a substantial group in the overall poverty statistics and are estimated to constitute 10% of European workers. This report examines in-work poverty in the European Union, picking up where a previous Eurofound report on this subject, published in 2010, ended. It looks at how in-work poverty evolved in the aftermath of the financial crisis of 2008, based on analysis of the latest data from the European Union Statistics on Income and Living Conditions (EU-SILC). While the prevalence of in-work poverty has been studied before, less is known about what it means to be one of the working poor. This report examines the social ramifications of in-work poverty by describing the well-being and living conditions of the working poor. It also looks at different measures adopted by governments to prevent or alleviate in-work poverty, especially indirect measures that improve the living standards of the working poor. These indirect measures have not received much policy attention compared with direct measures to increase incomes, such as minimum wages and social transfers

    GINI DP 2: Are European Social Safety Nets Tight Enough? Coverage and adequacy of minimum income schemes in 14 EU countries

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    This paper explores and compares the effectiveness of Minimum Income (MI) schemes in protecting persons of working age from poverty in the European Union. Using the European microsimulation model EUROMOD we estimate indicators of coverage and adequacy of MI schemes in 14 EU countries. In terms of coverage, we find that in several countries a significant number of individuals are ineligible for MI even when they fall below a poverty line set at 40 per cent of median income. With respect to adequacy, we show that in certain countries a large fraction of those entitled to MI remain at very low levels of income even when MI benefit is added. Overall, our findings suggest that the clustering of MI schemes in Europe may be more complex than previous literature has hitherto allowed for.

    A study of impact breakage of single rock specimen using discrete element method

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    Comminution is a critical stage of mineral processing which aims to reduce the size of ore particles through breakage, consequently increasing the likelihood of the liberation of valuable minerals. However, comminution is highly energy-intensive and an understanding of the key breakage mechanisms has been identified as an important factor in improving the efficiency of the process. Several factors, such as pre-existing cracks, mineralogical composition, ore shape and size are known to affect ore breakage behaviour during breakage. To investigate breakage mechanisms, it is important to be able to determine how individual factor influences the breakage behaviour of rock specimens. However, isolating and investigating individual factors under experimental conditions is challenging and typically impractical. Numerical techniques such as the Bonded Particle Model-Discrete Element Method (BPMDEM) have been developed as a means of investigating in isolation, the effects of different factors on ore breakage behaviour under closely controlled breakage conditions using synthetic rock specimens. This study investigates how individual factors influence rock specimen breakage using BPM-DEM numerical methods. Numerical simulations were conducted using ESyS-particle 2.3.5, an open-source discrete element method (DEM) software package which uses Python-based libraries to generate geometries and simulations and a C++ engine for mathematical computations. Empirical calibration relationships were developed to relate microstructural model parameters to the macroscopic mechanical properties that are typically obtained from standard geotechnical breakage experiments. The robustness of the model was evaluated by considering the sensitivity of fracture measures to the variation of model resolution, size-dependency and macroscopic mechanical properties (Young's modulus and uniaxial compressive strength) of the numerical specimens. A comparative study of single rock specimen breakage using the current BPM-DEM and laboratory SILC experiments carried out by Barbosa et al. (2019) was conducted. The measured fracture force and fracture patterns at different sizes for both cylindrical and spherical synthetic rock specimens were examined. Furthermore, the model was used to study, in isolation, the influence of pre-existing cracks in rock specimens and differing mineralogical compositions upon measurable breakage properties. Numerical rock specimens with pre-existing cracks were constructed using a microcrack approach, while a unique approach with the insertion of "seed points" was developed and demonstrated to construct numerical rock specimens with varying mineralogical compositions. Results from the numerical simulations showed that a high model resolution with a sufficiently large number of DEM-spheres exhibited results with the least deviation and error with respect to fracture measures, and, was therefore considered numerically stable. The dependency of fracture measurements on specimen size showed an expected increase in the measured fracture force as the specimen size increases. The variation of the macroscopic Young's modulus and uniaxial compressive strength against the fracture measures emphasised that the locus of these mechanical properties against the fracture measure can be used to specify a calibration relationship. Results of the comparative study showed that for both cylindrical and spherical rock specimens, the DEM consistently predicted the fragment patterns as well as the increase in the measured fracture force as the specimen size increased. The investigation on the effect of pre-existing cracks revealed that an increasing number of pre-existing cracks in rock specimens necessitated lower fracture force and consequently produced a low amount of new fracture surface area. For the binary phase mineralogical composition in the study, it was found that the fracture force decreased with an increase in the concentration of the softer component due to the increased percentage of weakness in the specimen. It was concluded that, with an appropriate calibration exercise and a realistic specification of material properties from the evaluation study, the DEM as a tool was sufficient to act as a "virtual laboratory" to isolate and study the individual effects of factors that influence ore breakage. The understanding of these results highlighted two important points. Firstly, this study was able to unravel some of the possible causes of the inefficiency in comminution practices, whereby significant amounts of energy can be expended to achieve minimal gains in respect of enhancing liberation due to pre-weakening and mineralogical composition. Secondly, it emphasised some of the causes of the variation observed during ore characterisation on a laboratory breakage device, attributable to pre-weakening and mineralogical composition

    Fuel poverty, older people and cold weather: An all-island analysis

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    Executive Summary This report covers a number of different aspects of fuel poverty and older people. 1. An exploration of existing government survey data from Northern Ireland and the Republic of Ireland with a particular focus on older people and conducting additional targeted analyses where required. 2. An original survey in the Republic of Ireland exploring the lived experience of older people in cold weather. 3. A feasibility study of data logging thermometers placed in the homes of older tenants in local authority accommodation. 4. Analysis of excess winter mortality among older people including a consideration of differences between the two jurisdictions. Older people on the island of Ireland, as in many other countries, experience a ‘dual burden’ in terms of fuel poverty. They are more likely to experience fuel poverty and are also particularly vulnerable to health and social harm as a result of this experience. The numbers of older people vulnerable to ill-effects from cold homes will rise as numbers of people aged 80 and over, and those living with chronic illness or disability, increase. There were significant differences observed between expenditure-based, and subjective (EU-SILC) based fuel poverty indicators, for older people, and between Northern Ireland and Republic of Ireland data. This data required careful interpretation. The higher levels of fuel poverty recorded for older people on the island of Ireland appeared to be driven by all aspects of the fuel poverty model - poor housing condition, energy inefficient housing, rising fuel prices and low income. The majority of older people live in their own home and these homes tend to be older properties which are detached or semi-detached. Older people on the island are over-represented among houses which are in poor condition and which lack central heating in both jurisdictions. Lacking central heating was a more common experience for older people in the Republic of Ireland than in Northern Ireland. Data on energy efficiency measures were not comparable North/South but similar patterns were observed. Older people were less likely than the general population to have attic/loft or wall insulation or double glazing. Older people were also vulnerable from an income point of view. This would seem to be a particular issue in Northern Ireland where rates of income poverty are significantly increasing. In both jurisdictions older people were heavily reliant on social transfers to keep them out of poverty. Coupled with this, there is evidence that many older people are not claiming their full entitlements. Oil dependency was a particular issue in Northern Ireland. Very significant increases were observed in the price of heating oil, as well as electricity and gas in recent years. There was little available research evidence on the relationship between the older consumer and heating oil suppliers
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