Application of XFaster power spectrum and likelihood estimator to Planck

We develop the XFaster Cosmic Microwave Background (CMB) temperature and polarization anisotropy power spectrum and likelihood technique for the Planck CMB satellite mission. We give an overview of this estimator and its current implementation and present the results of applying this algorithm to simulated Planck data. We show that it can accurately extract the power spectrum of Planck data for the high-l multipoles range. We compare the XFaster approximation for the likelihood to other high-l likelihood approximations such as Gaussian and Offset Lognormal and a low-l pixel-based likelihood. We show that the XFaster likelihood is not only accurate at high-l, but also performs well at moderately low multipoles. We also present results for cosmological parameter Markov Chain Monte Carlo estimation with the XFaster likelihood. As long as the low-l polarization and temperature power are properly accounted for, e.g., by adding an adequate low-l likelihood ingredient, the input parameters are recovered to a high level of accuracy.Comment: 25 pages, 20 figures, updated to reflect published version: slightly extended account of XFaster technique, added improved plots and minor corrections. Accepted for publication in MNRA

Decay of Nuclear Giant Resonances: Quantum Self-similar Fragmentation

Scaling analysis of nuclear giant resonance transition probabilities with increasing level of complexity in the background states is performed. It is found that the background characteristics, typical for chaotic systems lead to nontrivial multifractal scaling properties.Comment: 4 pages, LaTeX format, pc96.sty + 2 eps figures, accepted as: talk at the 8th Joint EPS-APS International Conference on Physics Computing (PC'96, 17-21. Sept. 1996), to appear in the Proceeding

A Bayesian estimate of the skewness of the Cosmic Microwave Background

We propose a formalism for estimating the skewness and angular power spectrum of a general Cosmic Microwave Background data set. We use the Edgeworth Expansion to define a non-Gaussian likelihood function that takes into account the anisotropic nature of the noise and the incompleteness of the sky coverage. The formalism is then applied to estimate the skewness of the publicly available 4 year Cosmic Background Explorer (COBE) Differential Microwave Radiometer data. We find that the data is consistent with a Gaussian skewness, and with isotropy. Inclusion of non Gaussian degrees of freedom has essentially no effect on estimates of the power spectrum, if each $C_\ell$ is regarded as a separate parameter or if the angular power spectrum is parametrized in terms of an amplitude (Q) and spectral index (n). Fixing the value of the angular power spectrum at its maxiumum likelihood estimate, the best fit skewness is S=6.5\pm6.0\times10^4(\muK)^3; marginalizing over Q the estimate of the skewness is S=6.5\pm8.4\times10^4(\muK)^3 and marginalizing over n one has S=6.5\pm8.5\times10^4(\muK)^3.Comment: submitted to Astrophysical Journal Letter

Different fractal properties of positive and negative returns

We perform an analysis of fractal properties of the positive and the negative changes of the German DAX30 index separately using Multifractal Detrended Fluctuation Analysis (MFDFA). By calculating the singularity spectra $f(\alpha)$ we show that returns of both signs reveal multiscaling. Curiously, these spectra display a significant difference in the scaling properties of returns with opposite sign. The negative price changes are ruled by stronger temporal correlations than the positive ones, what is manifested by larger values of the corresponding H\"{o}lder exponents. As regards the properties of dominant trends, a bear market is more persistent than the bull market irrespective of the sign of fluctuations.Comment: presented at FENS2007 conference, 8 pages, 4 Fig

Global Perspectives on Peer Sex Education for College Students

According to the World Health Organization, sexually transmitted diseases and infections continue to be a public health problem across the globe, with most infected persons being between the ages of 15 and 49. A large percentage of those affected by AIDS are 15-24 year olds, an age group which includes college students. Peer sex education is being espoused by non-governmental organizations and administrators as a viable solution to this problem. Peer education strategies and approaches to evaluation differ across programs. Some programs report increased efficacy for educators and trainees while other programs report increases in knowledge and changes in attitudes. Perceptions of peer education and resulting benefits vary based on cultural perspectives. Developers of peer education programs need to critically deconstruct current models and customize programs for particular settings, as demonstrated in several programs. Further research is needed on the effects of peer education on the educator and cultural implications