156 research outputs found

    Probing correlations of early magnetic fields using mu-distortion

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    The damping of a non-uniform magnetic field between the redshifts of about 10410^4 and 10610^6 injects energy into the photon-baryon plasma and causes the CMB to deviate from a perfect blackbody spectrum, producing a so-called μ\mu-distortion. We can calculate the correlation μT\langle\mu T\rangle of this distortion with the temperature anisotropy TT of the CMB to search for a correlation B2ζ\langle B^2\zeta\rangle between the magnetic field BB and the curvature perturbation ζ\zeta; knowing the B2ζ\langle B^2\zeta\rangle correlation would help us distinguish between different models of magnetogenesis. Since the perturbations which produce the μ\mu-distortion will be much smaller scale than the relevant density perturbations, the observation of this correlation is sensitive to the squeezed limit of B2ζ\langle B^2\zeta\rangle, which is naturally parameterized by bNLb_{\text{NL}} (a parameter defined analogously to fNLf_{\text{NL}}). We find that a PIXIE-like CMB experiments has a signal to noise S/N1.0×bNL(B~μ/10 nG)2S/N\approx 1.0 \times b_{\text{NL}} (\tilde B_\mu/10\text{ nG})^2, where B~μ\tilde B_\mu is the magnetic field's strength on μ\mu-distortion scales normalized to today's redshift; thus, a 10 nG field would be detectable with bNL=O(1)b_{\text{NL}}=\mathcal{O}(1). However, if the field is of inflationary origin, we generically expect it to be accompanied by a curvature bispectrum ζ3\langle\zeta^3\rangle induced by the magnetic field. For sufficiently small magnetic fields, the signal B2ζ\langle B^2 \zeta\rangle will dominate, but for B~μ1\tilde B_\mu\gtrsim 1 nG, one would have to consider the specifics of the inflationary magnetogenesis model. We also discuss the potential post-magnetogenesis sources of a B2ζ\langle B^2\zeta\rangle correlation and explain why there will be no contribution from the evolution of the magnetic field in response to the curvature perturbation.Comment: 23 pages, 1 figure. v2: Noted that a competing effect could potentially be smaller than originally stated. Fixed references. Matches JCAP versio

    Inflationary dynamics of kinetically-coupled gauge fields

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    We investigate the inflationary dynamics of two kinetically-coupled massless U(1)U(1) gauge fields with time-varying kinetic-term coefficients. Ensuring that the system does not have strongly coupled regimes shrinks the parameter space. Also, we further restrict ourselves to systems that can be quantized using the standard creation, annihilation operator algebra. This second constraint limits us to scenarios where the system can be diagonalized into the sum of two decoupled, massless, vector fields with a varying kinetic-term coefficient. Such a system might be interesting for magnetogenesis because of how the strong coupling problem generalizes. We explore this idea by assuming that one of the gauge fields is the Standard Model U(1)U(1) field and that the other dark gauge field has no particles charged under its gauge group. We consider whether it would be possible to transfer a magnetic field from the dark sector, generated perhaps before the coupling was turned on, to the visible sector. We also investigate whether the simple existence of the mixing provides more opportunities to generate magnetic fields. We find that neither possibility works efficiently, consistent with the well-known difficulties in inflationary magnetogenesis.Comment: 17 pages, 0 figures. Matches JCAP versio

    Povezava med laktozno intoleranco in kostno gostoto

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    Navigating the Postmodern Landscape: Embracing Interdisciplinary Openness in Pastoral Theology

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    In the face of rising secularization and the waning influence of the Church, contemporary pastoral theology encounters both a formidable challenge and an enticing opportunity in the postmod­ern era. This article explores how enhanced interdisciplinary engagement of pastoral theology can fos­ter a renewed approach to evangelization aligned with contemporary sensibilities. Through a compre­hensive literature review, we shed light on the experiences of the postmodern individual. By applying the analogy method and anchoring the concepts of “Logos Spermaticos” and “Influence and Vulnerabil­ity” in pastoral theology, we reveal its potential contribution to the interdisciplinary evolution of the con­cept of universal fraternity. The analysis shows that interdisciplinary collaboration in pastoral theology unfolds developmental prospects on two levels – learning from and learning with other disciplines. The “Logos Spermaticos” concept underscores the importance of acquiring new skills, empowering pastoral workers to communicate Christian doctrine more effectively. Simultaneously, the “Influence and Vulner­ability” concept fosters a dialogical approach, positioning pastoral theology as a respected interlocutor in contemporary interdisciplinary dialogues. Collaborative efforts with other disciplines empower pastoral theology to foster dialogue and deepen the idea of universal fraternity, both in academic discourse and practical application. The interdisciplinary and global development of fraternal humanism represents the necessary “loosening of the soil” for the seed of the Word of God to sprout in the future. Therefore, it becomes imperative for pastoral theology to transcend its conventional role, actively engaging in inter­disciplinary dialogue, thereby charting a course toward an elevated societal role and innovative avenues for proclaiming the Gospel

    Seismic resistance analysis of masonry building

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    In the Thesis the seismic performance assessment of the masonry building is presented. Firstly, different models for seismic resistance of unreinforced masonry wall are presented and the resistances determined on a typical wall by employing different models are evaluated and discused. Basically three failure mechanisms are considered in seismic performance assessment of masonry wall and are used for defining plastic hinges in equivalent frame. Usually the smallest shear resistance of the wall for the calculation of seismic resistance of simple masonry structure is sliding shear. In the second part of the Thesis an example of two storey masonry building is presented. The simplified nonlinear method for seismic performance assessment of structures, the N2 method was employed in the study. Therefore the nonlinear static (pushover) analysis was performed. Nonlinear behaviour of the material is captured by defining the plastic hinges into elements of equivalent frame. Before the nonlinear analysis with SAP2000 v.12 program, elastic analysis was made first. The pushover curve, which is a part of the N2 method implemented in SIST EN 1998-1: 2005 and represents the relationship between the base shear and the top displacement, was used for determination of target displacement. The damage in the structure was estimated at the target displacement and the peak ground acceleration, which corresponds to the near collapse limit state, was determined. In addition the analysis was performed for the case where the shear resistance due to diagonal cracking was considered the most adequate among other models. Lastly the program 3MURI, which is excellent tool to describe the non-linear in-plane mechanical behaviour of masonry panels was used for seismic performance assessment of the two-storey building. I

    Calculating the local-type fNL for slow-roll inflation with a non-vacuum initial state

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    Single-field slow-roll inflation with a non-vacuum initial state has an enhanced bispectrum in the local limit. We numerically calculate the local-type fNL signal in the CMB that would be measured for such models (including the full transfer function and 2D projection). The nature of the result depends on several parameters, including the occupation number N_k, the phase angle \theta_k between the Bogoliubov parameters, and the slow-roll parameter \epsilon. In the most conservative case, where one takes \theta_k \approx \eta_0 k (justified by physical reasons discussed within) and \epsilon\lesssim 0.01, we find that 0 < fNL < 1.52 (\epsilon/0.01), which is likely too small to be detected in the CMB. However, if one is willing to allow a constant value for the phase angle \theta_k and N_k=O(1), fNL can be much larger and/or negative (depending on the choice of \theta_k), e.g. fNL \approx 28 (\epsilon/0.01) or -6.4 (\epsilon/0.01); depending on \epsilon, these scenarios could be detected by Planck or a future satellite. While we show that these results are not actually a violation of the single-field consistency relation, they do produce a value for fNL that is considerably larger than that usually predicted from single-field inflation.Comment: 8 pages, 1 figure. v2: Version accepted for publication in PRD. Added greatly expanded discussion of the phase angle \theta_k; this allows the possibility of enhanced fNL, as mentioned in abstract. More explicit comparisons with earlier wor

    METODA GLOBALNOG ČITANJA

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    Metoda globalnog čitanja jedna je od različitih metoda opismenjavanja koja se može primijeniti i kod djece s autističnim poremećajem. Radi se o sintetičko-analitičkoj metodi, u kojoj se učenje provodi od čitavih riječi do pojedinačnih slova. Metodu globalnog čitanja upotrijebila sam kod 4 učenika s različitim stupnjevima autističnog poremećaja. Provodi se u dvije faze. Prva je faza namijenjena globalnom prepoznavanju riječi. Kada učenik prepozna oko 200 riječi, prelazi se na drugu fazu opismenjavanja, tj. učenje velikih i malih slova zajedno. Nakon završene druge faze čitanja djeca su sposobna čitati

    Investigando a consciência durante a improvisação

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    Este artigo relata um experimento realizado durante um processo de investigação sobre a improvisação e a interpretação na obra do saxofonista e compositor Nivaldo Ornelas. Esta pesquisa se embasou em conceitos dos autores Nettl, Benson e Berliner, assim como envolveu a organização de uma tipologia que reúne diversas categorias de improvisação. O experimento se deu sob condições controladas de gravação e objetivou estudar como três músicos experientes se comportariam melodicamente ao improvisar sobre material harmônico desconhecido por eles, extraído de uma música de Ornelas. Tal processo visou investigar se a consciência está presente no curso de uma improvisação e como é possível aferi-la. Por intermédio das transcrições dos improvisos e das entrevistas realizadas com os músicos posteriormente, se pôde observar que os improvisadores realizaram uma análise melódica em tempo real. Constatou-se que eles recorreram a estudos passados durante a execução. Por fim, concluiu-se que a consciência está presente nas diversas categorias de improvisação, incluída a realizada sobre harmonia desconhecida
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