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Author |
Olmo, G.J. |
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Title |
Birkhoff's theorem and perturbations in f(R) theories |
Type |
Journal Article |
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Year |
2012 |
Publication |
Annalen der Physik |
Abbreviated Journal |
Ann. Phys.-Berlin |
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Volume |
524 |
Issue |
5 |
Pages |
87-88 |
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Abstract |
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Address |
[Olmo, Gonzalo J.] Univ Valencia, Fac Fis, Dept Fis Teor, E-46100 Valencia, Spain, Email: gonzalo.olmo@uv.es |
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Publisher |
Wiley-V C H Verlag Gmbh |
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Language |
English |
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ISSN |
0003-3804 |
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Conference |
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Notes  |
WOS:000303662900008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
1013 |
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Author |
de Putter, R.; Wagner, C.; Mena, O.; Verde, L.; Percival, W.J. |
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Title |
Thinking outside the box: effects of modes larger than the survey on matter power spectrum covariance |
Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
04 |
Issue |
4 |
Pages |
019 - 31pp |
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Keywords |
galaxy clustering; power spectrum; cosmological simulations; dark matter simulations |
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Abstract |
Accurate power spectrum (or correlation function) covariance matrices are a crucial requirement for cosmological parameter estimation from large scale structure surveys. In order to minimize reliance on computationally expensive mock catalogs, it is important to have a solid analytic understanding of the different components that make up a covariance matrix. Considering the matter power spectrum covariance matrix, it has recently been found that there is a potentially dominant effect on mildly non-linear scales due to power in modes of size equal to and larger than the survey volume. This beat coupling effect has been derived analytically in perturbation theory and while it has been tested with simulations, some questions remain unanswered. Moreover, there is an additional effect of these large modes, which has so far not been included in analytic studies, namely the effect on the estimated average density which enters the power spectrum estimate. In this article, we work out analytic, perturbation theory based expressions including both the beat coupling and this local average effect and we show that while, when isolated, beat coupling indeed causes large excess covariance in agreement with the literature, in a realistic scenario this is compensated almost entirely by the local average effect, leaving only similar to 10% of the excess. We test our analytic expressions by comparison to a suite of large N-body simulations, using both full simulation boxes and subboxes thereof to study cases without beat coupling, with beat coupling and with both beat coupling and the local average effect. For the variances, we find excellent agreement with the analytic expressions for k < 0.2 hMpc(-1) at z = 0.5, while the correlation coefficients agree to beyond k = 0.4 hMpc(-1). As expected, the range of agreement increases towards higher redshift and decreases slightly towards z = 0. We finish by including the large-mode effects in a full covariance matrix description for arbitrary survey geometry and confirming its validity using simulations. This may be useful as a stepping stone towards building an actual galaxy (or other tracer's) power spectrum covariance matrix. |
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Address |
[de Putter, Roland; Wagner, Christian; Verde, Lica] Univ Barcelona IEEC UB, ICC, Barcelona 08028, Spain, Email: rdeputter@berkeley.edu; |
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Publisher |
Iop Publishing Ltd |
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Language |
English |
Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000303665000019 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1016 |
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Author |
Pierre Auger Collaboration (Abreu, P. et al); Pastor, S. |
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Title |
A search for anisotropy in the arrival directions of ultra high energy cosmic rays recorded at the Pierre Auger Observatory |
Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
04 |
Issue |
4 |
Pages |
040 - 21pp |
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Keywords |
ultra high energy cosmic rays; cosmic ray experiments |
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Abstract |
Observations of cosmic rays arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects drawn from the Veron-Cetty Veron catalog. In this paper we report on the use of three catalog independent methods to search for anisotropy. The 2pt-L, 2pt+ and 3pt methods, each giving a different measure of self-clustering in arrival directions, were tested on mock cosmic ray data sets to study the impacts of sample size and magnetic smearing on their results, accounting for both angular and energy resolutions. If the sources of UHECRs follow the same large scale structure as ordinary galaxies in the local Universe and if UHECRs are deflected no more than a few degrees, a study of mock maps suggests that these three method can efficiently respond to the resulting anisotropy with a P-value = 1.0% or smaller with data sets as few as 100 events. using data taken from January 1, 2004 to July 31, 2010 we examined the 20, 30, ... , 110 highest energy events with a corresponding minimum energy threshold of about 49.3 EeV. The minimum P-values found were 13.5% using the 2pt-L method, 1.0% using the 2pt+ method and 1.1% using the 3pt method for the highest 100 energy events. In view of the multiple (correlated) scans performed on the data set, these catalog-independent methods do not yield strong evidence of anisotropy in the highest energy cosmic rays. |
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Address |
[Abreu, P.; Andringa, S.; Assis, P.; Brogueira, P.; Cazon, L.; Conceicao, R.; Diogo, F.; Espadana, J.; Goncalves, P.; Pimenta, M.; Santo, C. E.; Santos, E.; Tome, B.] Univ Tecn Lisboa, LIP, P-1100 Lisbon, Portugal, Email: auger_spokesperson@fnal.gov |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Language |
English |
Summary Language |
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Series Volume |
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Edition |
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ISSN |
1475-7516 |
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Expedition |
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Conference |
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Notes |
WOS:000303665000040 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1015 |
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Author |
Botella-Soler, V.; Oteo, J.A.; Ros, J. |
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Title |
Coexistence of periods in a bifurcation |
Type |
Journal Article |
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Year |
2012 |
Publication |
Chaos, Solitons & Fractals |
Abbreviated Journal |
Chaos Solitons Fractals |
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Volume |
45 |
Issue |
5 |
Pages |
681-686 |
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Keywords |
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Abstract |
A particular type of order-to-chaos transition mediated by an infinite set of coexisting neutrally stable limit cycles of different periods is studied in the Varley-Gradwell-Hassell population model. We prove by an algebraic method that this kind of transition can only happen for a particular bifurcation parameter value. Previous results on the structure of the attractor at the transition point are here simplified and extended. |
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Address |
[Botella-Soler, V.; Oteo, J. A.; Ros, J.] Univ Valencia, Dept Fis Teor, E-46100 Valencia, Spain, Email: vicente.botella@uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Pergamon-Elsevier Science Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0960-0779 |
ISBN |
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Conference |
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Notes |
WOS:000303785300014 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
1005 |
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Author |
David, M.; Borges, G.; Gomes, J.; Pina, J.; Campos, I.; Fernandez, E.; Lopez, A.; Orviz, P.; Cacheiro, J.L.; Fernandez, C.; Simon, A.; Fernandez, A. |
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Title |
Software Provision Process For EGI |
Type |
Journal Article |
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Year |
2012 |
Publication |
Computing and Informatics |
Abbreviated Journal |
Comput. Inform. |
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Volume |
31 |
Issue |
1 |
Pages |
135-148 |
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Keywords |
Grid infrastructures; Grid middleware; European Grid Infrastructure; European Middleware Initiative |
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Abstract |
The European Grid Initiative (EGI) provides a sustainable pan-European Grid computing infrastructure for e-Science based on a network of regional and national Grids. The middleware driving this production infrastructure is constantly adapted to the changing needs of the EGI Community by deploying new features and phasing out other features and components that are no longer needed. Unlike previous e-Infrastructure projects, EGI does not develop its own middleware solution, but instead sources the required components from Technology Providers and integrates them in the Unified Middleware Distribution (UMD). In order to guarantee a high quality and reliable operation of the infrastructure, all UMD software must undergo a release process that covers the definition of the functional, performance and quality requirements, the verification of those requirements and testing in production environments. |
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Address |
[David, Mario; Borges, Goncalo; Gomes, Jorge; Pina, Joao] Lab Instrumentacao & Fis Expt Particulas, Lisbon, Portugal, Email: david@lip.pt |
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Corporate Author |
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Thesis |
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Publisher |
Slovak Acad Sciences Inst Informatics |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1335-9150 |
ISBN |
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Conference |
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Notes |
WOS:000303785400011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1086 |
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