4,054 research outputs found

    CMB Polarization Experiments

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    We discuss the analysis of polarization experiments with particular emphasis on those that measure the Stokes parameters on a ring on the sky. We discuss the ability of these experiments to separate the EE and BB contributions to the polarization signal. The experiment being developed at Wisconsin university is studied in detail, it will be sensitive to both Stokes parameters and will concentrate on large scale polarization, scanning a 47o47^o degree ring. We will also consider another example, an experiment that measures one of the Stokes parameters in a 1o1^o ring. We find that the small ring experiment will be able to detect cosmological polarization for some models consistent with the current temperature anisotropy data, for reasonable integration times. In most cosmological models large scale polarization is too small to be detected by the Wisconsin experiment, but because both QQ and UU are measured, separate constraints can be set on EE and BB polarization.Comment: 27 pages with 12 included figure

    Adding school to work–family balance: The role of support for Portuguese working mothers attending a master’s degree

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    This qualitative study examines the work, family, and study experiences of Portuguese professional women in two different career stages: early career and mid-career. Using semi-structured interviews with a sample of 22 working mothers enrolled in a master’s degree, this study explores their experiences of combining the roles of mother, worker and student and the role of support for a successful integration of work–family and school. Support from peers was found to be a critical factor for successfully integrating work–family and school responsibilities. Differences in the use of partner and family support were found between early and mid-career women. Lack of or limited support from the workplace was a barrier that emerged in both groups.info:eu-repo/semantics/publishedVersio

    Sequences of purchases in credit card data reveal life styles in urban populations

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    Zipf-like distributions characterize a wide set of phenomena in physics, biology, economics and social sciences. In human activities, Zipf-laws describe for example the frequency of words appearance in a text or the purchases types in shopping patterns. In the latter, the uneven distribution of transaction types is bound with the temporal sequences of purchases of individual choices. In this work, we define a framework using a text compression technique on the sequences of credit card purchases to detect ubiquitous patterns of collective behavior. Clustering the consumers by their similarity in purchases sequences, we detect five consumer groups. Remarkably, post checking, individuals in each group are also similar in their age, total expenditure, gender, and the diversity of their social and mobility networks extracted by their mobile phone records. By properly deconstructing transaction data with Zipf-like distributions, this method uncovers sets of significant sequences that reveal insights on collective human behavior.Comment: 30 pages, 26 figure

    Cosmological Recombination of Lithium and its Effect on the Microwave Background Anisotropies

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    The cosmological recombination history of lithium, produced during Big--Bang nucleosynthesis, is presented using updated chemistry and cosmological parameters consistent with recent cosmic microwave background (CMB) measurements. For the popular set of cosmological parameters, about a fifth of the lithium ions recombine into neutral atoms by a redshift z∼400z\sim 400. The neutral lithium atoms scatter resonantly the CMB at 6708 \AA and distort its intensity and polarization anisotropies at observed wavelengths around ∼300μ\sim 300 \mum, as originally suggested by Loeb (2001). The modified anistropies resulting from the lithium recombination history are calculated for a variety of cosmological models and found to result primarily in a suppression of the power spectrum amplitude. Significant modification of the power spectrum occurs for models which assume a large primordial abundance of lithium. While detection of the lithium signal might prove difficult, if offers the possibility of inferring the lithium primordial abundance and is the only probe proposed to date of the large-scale structure of the Universe for z∼500−100z\sim 500-100.Comment: 20 pages, 7 figure
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