The Bispectrum of IRAS Galaxies

We compute the bispectrum for the galaxy distribution in the IRAS QDOT, 2Jy, and 1.2Jy redshift catalogs for wavenumbers 0.05<k<0.2 h/Mpc and compare the results with predictions from gravitational instability in perturbation theory. Taking into account redshift space distortions, nonlinear evolution, the survey selection function, and discreteness and finite volume effects, all three catalogs show evidence for the dependence of the bispectrum on configuration shape predicted by gravitational instability. Assuming Gaussian initial conditions and local biasing parametrized by linear and non-linear bias parameters b_1 and b_2, a likelihood analysis yields 1/b_1 = 1.32^{+0.36}_{-0.58}, 1.15^{+0.39}_{-0.39} and b_2/b_1^2=-0.57^{+0.45}_{-0.30}, -0.50^{+0.31}_{-0.51}, for the for the 2Jy and 1.2Jy samples, respectively. This implies that IRAS galaxies trace dark matter increasingly weakly as the density contrast increases, consistent with their being under-represented in clusters. In a model with chi^2 non-Gaussian initial conditions, the bispectrum displays an amplitude and scale dependence different than that found in the Gaussian case; if IRAS galaxies do not have bias b_1> 1 at large scales, \chi^2 non-Gaussian initial conditions are ruled out at the 95% confidence level. The IRAS data do not distinguish between Lagrangian or Eulerian local bias.Comment: 30 pages, 11 figure

BAO+BBN revisited -- Growing the Hubble tension with a 0.7km/s/Mpc constraint

The combination of Baryonic Acoustic Oscillation (BAO) data together with light element abundance measurements from Big Bang Nucleosynthesis (BBN) has been shown to constrain the cosmological expansion history to an unprecedented degree. Using the newest LUNA data and DR16 data from SDSS, the BAO+BBN probe puts tight constraints on the Hubble parameter ($H_0 = 67.6 \pm 1.0 \mathrm{km/s/Mpc}$), resulting in a $3.7\sigma$ tension with the local distance ladder determination from SH0ES in a $\Lambda$CDM model. In the updated BAO data the high- and low-redshift subsets are mutually in excellent agreement, and there is no longer a mild internal tension to artificially enhance the constraints. Adding the recently-developed ShapeFit analysis yields $H_0 = 68.3 \pm 0.7 \mathrm{km/s/Mpc}$ ($3.8 \sigma$ tension). For combinations with additional data sets, there is a strong synergy with the sound horizon information of the cosmic microwave background, which leads to one of the tightest constraints to date, $H_0 = 68.30\pm 0.45\mathrm{km/s/Mpc}$, in $4.2\sigma$ tension with SH0ES. The region preferred by this combination is perfectly in agreement with that preferred by ShapeFit. The addition of supernova data also yields a $4.2\sigma$ tension with SH0ES for Pantheon, and a $3.5\sigma$ tension for PantheonPLUS. Finally, we show that there is a degree of model-dependence of the BAO+BBN constraints with respect to early-time solutions of the Hubble tension, and the loss of constraining power in extended models depends on whether the model can be additionally constrained from BBN observations.Comment: 27 pages, 9 figures, 1 table. Comments are welcome

Baryon Self-Energy With QQQ Bethe-Salpeter Dynamics In The Non-Perturbative QCD Regime: n-p Mass Difference

A qqq BSE formalism based on DB{\chi}S of an input 4-fermion Lagrangian of `current' u,d quarks interacting pairwise via gluon-exchange-propagator in its {\it non-perturbative} regime, is employed for the calculation of baryon self-energy via quark-loop integrals. To that end the baryon-qqq vertex function is derived under Covariant Instantaneity Ansatz (CIA), using Green's function techniques. This is a 3-body extension of an earlier q{\bar q} (2-body) result on the exact 3D-4D interconnection for the respective BS wave functions under 3D kernel support, precalibrated to both q{\bar q} and qqq spectra plus other observables. The quark loop integrals for the neutron (n) - proton (p) mass difference receive contributions from : i) the strong SU(2) effect arising from the d-u mass difference (4 MeV); ii) the e.m. effect of the respective quark charges. The resultant n-p difference comes dominantly from d-u effect (+1.71 Mev), which is mildly offset by e.m.effect (-0.44), subject to gauge corrections. To that end, a general method for QED gauge corrections to an arbitrary momentum dependent vertex function is outlined, and on on a proportionate basis from the (two-body) kaon case, the net n-p difference works out at just above 1 MeV. A critical comparison is given with QCD sum rules results.Comment: be 27 pages, Latex file, and to be published in IJMPA, Vol 1

Signature of short distance physics on inflation power spectrum and CMB anisotropy

The inflaton field responsible for inflation may not be a canonical fundamental scalar. It is possible that the inflaton is a composite of fermions or it may have a decay width. In these cases the standard procedure for calculating the power spectrum is not applicable and a new formalism needs to be developed to determine the effect of short range interactions of the inflaton on the power spectrum and the CMB anisotropy. We develop a general formalism for computing the power spectrum of curvature perturbations for such non-canonical cases by using the flat space K\"all\'en-Lehmann spectral function in curved quasi-de Sitter space assuming implicitly that the Bunch-Davis boundary conditions enforces the inflaton mode functions to be plane wave in the short wavelength limit and a complete set of mode functions exists in quasi-de Sitter space. It is observed that the inflaton with a decay width suppresses the power at large scale while a composite inflaton's power spectrum oscillates at large scales. These observations may be vindicated in the WMAP data and confirmed by future observations with PLANCK.Comment: 17 pages, 4 figures, Extended journal version, Accepted for publication in JCA

Measuring the Nonlinear Biasing Function from a Galaxy Redshift Survey

We present a simple method for evaluating the nonlinear biasing function of galaxies from a redshift survey. The nonlinear biasing is characterized by the conditional mean of the galaxy density fluctuation given the underlying mass density fluctuation, or by the associated parameters of mean biasing and nonlinearity (following Dekel & Lahav 1999). Using the distribution of galaxies in cosmological simulations, at smoothing of a few Mpc, we find that the mean biasing can be recovered to a good accuracy from the cumulative distribution functions (CDFs) of galaxies and mass, despite the biasing scatter. Then, using a suite of simulations of different cosmological models, we demonstrate that the matter CDF is robust compared to the difference between it and the galaxy CDF, and can be approximated for our purpose by a cumulative log-normal distribution of 1+\delta with a single parameter \sigma. Finally, we show how the nonlinear biasing function can be obtained with adequate accuracy directly from the observed galaxy CDF in redshift space. Thus, the biasing function can be obtained from counts in cells once the rms mass fluctuation at the appropriate scale is assumed a priori. The relative biasing function between different galaxy types is measurable in a similar way. The main source of error is sparse sampling, which requires that the mean galaxy separation be smaller than the smoothing scale. Once applied to redshift surveys such as PSCz, 2dF, SDSS, or DEEP, the biasing function can provide valuable constraints on galaxy formation and structure evolution.Comment: 23 pages, 7 figures, revised version, accepted for publication in Ap

Experiência em pesquisa: a trajetória do Grupo de Pesquisa em usuários de informação

Se comparte la trayectoria del Grupo de Investigación sobre Usuarios de la Información perteneciente a la cátedra “Usuarios de la Información” de la Escuela de Bibliotecología, Facultad de Filosofía y Humanidades de la Universidad Nacional de Córdoba, Argentina. Se muestra la evolución, desarrollo y crecimiento del mismo, así como de las investigadoras que lo integran. Se exponen y explican brevemente las investigaciones realizadas y la investigación en curso, partiendo de la teoría de la sociedad de las tecnologías de la información (Castells, 2002), de las que aportaron a la evolución de la alfabetización en información (Kunhlthau - 1987; Bruce - 1997, Eisenberg - 1998, SCONUL - 1999; ACRL - 1989; Webber y Johnson - 2002; Walter - 2007 y UNESCO - 2008). Como así también las teorías de Aprendizaje de Bruner, Ausubel y Vygotsky. Se finaliza la presente ponencia realizando una proyección sobre el futuro de este grupo tomando como referencia los frutos resultantes de las investigaciones que marcaron esta trayectoria

First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Inflation

We confront predictions of inflationary scenarios with the WMAP data, in combination with complementary small-scale CMB measurements and large-scale structure data. The WMAP detection of a large-angle anti-correlation in the temperature--polarization cross-power spectrum is the signature of adiabatic superhorizon fluctuations at the time of decoupling. The WMAP data are described by pure adiabatic fluctuations: we place an upper limit on a correlated CDM isocurvature component. Using WMAP constraints on the shape of the scalar power spectrum and the amplitude of gravity waves, we explore the parameter space of inflationary models that is consistent with the data. We place limits on inflationary models; for example, a minimally-coupled lambda phi^4 is disfavored at more than 3-sigma using WMAP data in combination with smaller scale CMB and large scale structure survey data. The limits on the primordial parameters using WMAP data alone are: n_s(k_0=0.002 Mpc^{-1})=1.20_{-0.11}^{+0.12}, dn/dlnk=-0.077^{+0.050}_{- 0.052}, A(k_0=0.002 Mpc}^{-1})=0.71^{+0.10}_{-0.11} (68% CL), and r(k_0=0.002 Mpc^{-1})<1.28 (95% CL).Comment: Accepted by ApJ; 49 pages, 9 figures. V2: Gives constraints from WMAP data alone. Corrected approximation which made the constraints in Table 1 to shift slightly. Corrected the Inflation Flow following the revision to Kinney, astro-ph/0206032. No conclusions have been changed. For a detailed list of changes see http://www.astro.princeton.edu/~hiranya/README.ERRATA.tx

Statistical methods in cosmology

The advent of large data-set in cosmology has meant that in the past 10 or 20 years our knowledge and understanding of the Universe has changed not only quantitatively but also, and most importantly, qualitatively. Cosmologists rely on data where a host of useful information is enclosed, but is encoded in a non-trivial way. The challenges in extracting this information must be overcome to make the most of a large experimental effort. Even after having converged to a standard cosmological model (the LCDM model) we should keep in mind that this model is described by 10 or more physical parameters and if we want to study deviations from it, the number of parameters is even larger. Dealing with such a high dimensional parameter space and finding parameters constraints is a challenge on itself. Cosmologists want to be able to compare and combine different data sets both for testing for possible disagreements (which could indicate new physics) and for improving parameter determinations. Finally, cosmologists in many cases want to find out, before actually doing the experiment, how much one would be able to learn from it. For all these reasons, sophisiticated statistical techniques are being employed in cosmology, and it has become crucial to know some statistical background to understand recent literature in the field. I will introduce some statistical tools that any cosmologist should know about in order to be able to understand recently published results from the analysis of cosmological data sets. I will not present a complete and rigorous introduction to statistics as there are several good books which are reported in the references. The reader should refer to those.Comment: 31, pages, 6 figures, notes from 2nd Trans-Regio Winter school in Passo del Tonale. To appear in Lectures Notes in Physics, "Lectures on cosmology: Accelerated expansion of the universe" Feb 201

Serum anti‐müllerian hormone levels and risk of premature ovarian insufficiency in female childhood cancer survivors: Systematic review and network meta‐analysis

Background: Female childhood cancer survivors (CCS) might have impaired ovarian reserves, especially after alkylating agents or radiotherapy. The purpose of this systematic review and network meta‐analysis is to evaluate the role of serum anti‐Müllerian hormone (AMH) for ovarian reserve screening and the risk of premature ovarian insufficiency (POI) according to the subtype of childhood cancer. (2) Methods: PRISMA‐NMA guidelines were followed. We carried out a network meta‐analysis based on a random effects model for mixed multiple treatment comparisons to rank childhood cancers effects on fertility by surface under the cumulative ranking curve (SUCRA). Studies were selected only if they had an age‐matched control group. Quality assessment was performed using Newcastle–Ottawa Scale. The co‐primary outcomes were mean AMH levels and the incidence of POI. (3) Results: A total of 8 studies (1303 participants) were included. Women treated for a neuroblastoma during infancy were more likely to be ranked first for impaired AMH levels (SUCRA = 65.4%), followed by mixed CCS (SUCRA = 29.6%). The greatest rates of POI were found in neuroblastoma survivors (SUCRA = 42.5%), followed by acute lymphoid leukemia (SUCRA = 26.3%) or any other neoplasia (SUCR A= 20.5%). (4) Conclusions: AMH represents a trustworthy approach for ovarian reserve screening. Direct and indirect comparisons found no differences in mean AMH levels and POI risk between subtypes of CCS and healthy controls. SUCRA analysis showed that female neuroblastoma survivors were more at risk for reduced serum AMH levels and increased risk of POI

Analysis of an atom laser based on the spatial control of the scattering length

In this paper we analyze atom lasers based on the spatial modulation of the scattering length of a Bose-Einstein Condensate. We demonstrate, through numerical simulations and approximate analytical methods, the controllable emission of matter-wave bursts and study the dependence of the process on the spatial dependence of the scattering length along the axis of emission. We also study the role of an additional modulation of the scattering length in time.Comment: Submitted to Phys. Rev.