2,438 research outputs found

    CMB statistical isotropy confirmation at all scales using multipole vectors

    Full text link
    We present an efficient numerical code and conduct, for the first time, a null and model-independent CMB test of statistical isotropy using Multipole Vectors (MVs) at all scales. Because MVs are insensitive to the angular power spectrum CC_\ell, our results are independent from the assumed cosmological model. We avoid a posteriori choices and use pre-defined ranges of scales [2,30]\ell\in[2,30], [2,600]\ell\in[2,600] and [2,1500]\ell\in[2,1500] in our analyses. We find that all four masked Planck maps, from both 2015 and 2018 releases, are in agreement with statistical isotropy for [2,30]\ell\in[2,30], [2,600]\ell\in[2,600]. For [2,1500]\ell\in[2,1500] we detect anisotropies but this is indicative of simply the anisotropy in the noise: there is no anisotropy for <1300\ell < 1300 and an increasing level of anisotropy at higher multipoles. Our findings of no large-scale anisotropies seem to be a consequence of avoiding \emph{a posteriori} statistics. We also find that the degree of anisotropy in the full sky (i.e. unmasked) maps vary enormously (between less than 5 and over 1000 standard deviations) among the different mapmaking procedures and data releases.Comment: v4: additional analysis which increased statistical sensitivity, including new plots and tables; extended discussion; 15 pages, 14 figures, 7 tables. Matches published versio

    Angular-planar CMB power spectrum

    Full text link
    Gaussianity and statistical isotropy of the Universe are modern cosmology's minimal set of hypotheses. In this work we introduce a new statistical test to detect observational deviations from this minimal set. By defining the temperature correlation function over the whole celestial sphere, we are able to independently quantify both angular and planar dependence (modulations) of the CMB temperature power spectrum over different slices of this sphere. Given that planar dependence leads to further modulations of the usual angular power spectrum ClC_l, this test can potentially reveal richer structures in the morphology of the primordial temperature field. We have also constructed an unbiased estimator for this angular-planar power spectrum which naturally generalizes the estimator for the usual ClC_l's. With the help of a chi-square analysis, we have used this estimator to search for observational deviations of statistical isotropy in WMAP's 5 year release data set (ILC5), where we found only slight anomalies on the angular scales l=7l=7 and l=8l=8. Since this angular-planar statistic is model-independent, it is ideal to employ in searches of statistical anisotropy (e.g., contaminations from the galactic plane) and to characterize non-Gaussianities.Comment: Replaced to match the published version. Journal-ref: Phys.Rev. D80 063525 (2009

    Cosmological Signatures of Anisotropic Spatial Curvature

    Get PDF
    If one is willing to give up the cherished hypothesis of spatial isotropy, many interesting cosmological models can be developed beyond the simple anisotropically expanding scenarios. One interesting possibility is presented by shear-free models in which the anisotropy emerges at the level of the curvature of the homogeneous spatial sections, whereas the expansion is dictated by a single scale factor. We show that such models represent viable alternatives to describe the large-scale structure of the inflationary universe, leading to a kinematically equivalent Sachs-Wolfe effect. Through the definition of a complete set of spatial eigenfunctions we compute the two-point correlation function of scalar perturbations in these models. In addition, we show how such scenarios would modify the spectrum of the CMB assuming that the observations take place in a small patch of a universe with anisotropic curvature.Comment: 21 pages, 1 figure. To appear in JCA

    Inflationary Perturbations in Anisotropic, Shear-Free Universes

    Full text link
    In this work, the linear and gauge-invariant theory of cosmological perturbations in a class of anisotropic and shear-free spacetimes is developed. After constructing an explicit set of complete eigenfunctions in terms of which perturbations can be expanded, we identify the effective degrees of freedom during a generic slow-roll inflationary phase. These correspond to the anisotropic equivalent of the standard Mukhanov-Sasaki variables. The associated equations of motion present a remarkable resemblance to those found in perturbed Friedmann-Robertson-Walker spacetimes with curvature, apart from the spectrum of the Laplacian, which exhibits the characteristic frequencies of the underlying geometry. In particular, it is found that the perturbations cannot develop arbitrarily large super-Hubble modes.Comment: 24 pages, 2 figure

    Endothelial Dysfunction in the Apolipoprotein E-deficient Mouse: insights into the influence of diet, gender and aging

    Get PDF
    Since the early 1990s, several strains of genetically modified mice have been developed as models for experimental atherosclerosis. Among the available models, the apolipoprotein E-deficient (apoE-/-) mouse is of particular relevance because of its propensity to spontaneously develop hypercholesterolemia and atherosclerotic lesions that are similar to those found in humans, even when the mice are fed a chow diet. The main purpose of this review is to highlight the key achievements that have contributed to elucidating the mechanisms pertaining to vascular dysfunction in the apoE-/- mouse. First, we summarize lipoproteins and atherosclerosis phenotypes in the apoE-/- mouse, and then we briefly discuss controversial evidence relative to the influence of gender on the development of atherosclerosis in this murine model. Second, we discuss the main mechanisms underlying the endothelial dysfunction of conducting vessels and resistance vessels and examine how this vascular defect can be influenced by diet, aging and gender in the apoE-/- mouse

    ATR-FTIR Spectroscopy for the Assessment of Biochemical Changes in Skin Due to Cutaneous Squamous Cell Carcinoma

    Get PDF
    Nonmelanoma skin cancers represent 95% of cutaneous neoplasms. Among them, squamous cell carcinoma (SCC) is the more aggressive form and shows a pattern of possible metastatic profile. in this work, we used Fourier transform infrared spectroscopy (FTIR) spectroscopy to assess the biochemical changes in normal skin caused by squamous cell carcinoma induced by multi-stage chemical carcinogenesis in mice. Changes in the absorption intensities and shifts were observed in the vibrational modes associated to proteins, indicating changes in secondary conformation in the neoplastic tissue. Hierarchical cluster analysis was performed to evaluate the potential of the technique to differentiate the spectra of neoplastic and normal skin tissue, so that the accuracy obtained for this classification was 86.4%. in this sense, attenuated total reflection (ATR)-FTIR spectroscopy provides a useful tool to complement histopathological analysis in the clinical routine for the diagnosis of cutaneous squamous cell carcinoma.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Instituto Nacional de Ciencia e Tecnologia Fotonica (INCT)Produtividade em Pesquisa (PQ)IPEN CNEN SP, Ctr Lasers & Applicat, Inst Pesquisas Energet & Nucl, BR-05508000 São Paulo, SP, BrazilUniv São Paulo, Sch Dent, BR-05508000 São Paulo, SP, BrazilUniversidade Federal de São Paulo, ICT, BR-1223128 Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo, ICT, BR-1223128 Sao Jose Dos Campos, SP, BrazilFAPESP: 05/51689-2CAPES: 071/2013-88881.068505/2014-01Instituto Nacional de Ciencia e Tecnologia Fotonica (INCT): 573.916/2008-0Produtividade em Pesquisa (PQ): 312397/2013-5Web of Scienc

    Design and construction of a didactic standalone photovoltaic plant

    Full text link
    This paper proposes the design and construction of a standalone didactic photovoltaic (PV) plant. The system components are available as a didactic kit to the students of the Federal Institute of Education, Science and Technology of Ceará (IFCE), Brazil. Thus, contributing to the teaching-learning process and providing a system to be used in future researches. In addition, the system was designed for supplying electricity to the lighting circuit of the Energy Processing Laboratory, located at IFCE Fortaleza Campus. The PV system developed during the work has an autonomy of 900 Ah and the total installed power of 840 Wp. Using a data capture system, a generation generated by the PV microgeneration was registered in operation up to 647 W

    Gut microbiota, diet, and chronic diseases: the role played by oxidative stress

    Get PDF
    The authors gratefully acknowledge the Espirito Santo Research Foundation (FAPES) (Grant CNPq/FAPES No. 24/2018; Termo Outorga 569/2018) and the Brazilian National Council for Research and Development (CNPq) (CNPq Grant Bolsa Produtividade 2015-2019) for the financial support to our research projectS
    corecore