Initial conditions for cosmological perturbations in scalar-tensor dark-energy models

We discuss the evolution and imprints of isocurvature initial conditions for the scalar field in scalar tensor extensions of Einstein gravity. We consider the simplest models of scalar tensor theories, as Induced gravity (IG, which can be recasted in form of Jordan-Brans-Dicke theory by a redefinition of the scalar field) or non-minimally coupled (NMC) scalar fields in which the acceleration of the Universe is connected to a variation of the effective Planck mass. After introducing the fundamental ideas of cosmological perturbation theory and scalar tensor theories of gravity, we give the evolution equations for matter, metric and scalar field fluctuations in synchronous gauge. We use this set of equations for both the IG and the NMC models to find a new isocurvature solution in which the scalar field fluctuations compensate for the relativistic components respectively. We also show how we can generalize the well known isocurvature modes in Einstein GR to these models. We show the different evolution of cosmological fluctuations for these isocurvature initial conditions compared to the standard adiabatic one. After that, we compute the CMB angular power spectrum for these solutions in the IG model, with the help of a modified Einstein-Boltzmann CLASS code. In particular the CMB power spectrum is computed separately for adiabatic and isocurvature initial conditions, i.e. for totally uncorrelated modes, and with arbitrary correlations leading to an interesting explanation of the lack of power in the low multipoles region of the CMB temperature power spectrum. Finally we show how a simple model of double inflation in IG could explain the generation of the new isocurvature mode

Isocurvature fluctuations in the effective Newton's constant

We present a new isocurvature mode present in scalar-tensor theories of gravity that corresponds to a regular growing solution in which the energy of the relativistic degrees of freedom and the scalar field that regulates the gravitational strength compensate during the radiation dominated epoch on scales much larger than the Hubble radius. We study this isocurvature mode and its impact on anisotropies of the cosmic microwave background for the simplest scalar-tensor theory, i.e. the extended Jordan-Brans-Dicke gravity, in which the scalar field also drives the acceleration of the Universe. We use Planck data to constrain the amplitude of this isocurvature mode in the case of fixed correlation with the adiabatic mode and we show how this mode could be generated in a simple two field inflation model.Comment: Version updated to match published version. No changes in the result

Infanticide and Sex Ratio at Birth in Contemporary Italy

Despite the doubts on the reliability of the infanticide data available for Italy, it can be shown that the phenomenon continues to decrease. Nowadays, cases of infanticide can be interpreted as the consequence of lack of information on the possibility to terminate pregnancy legally. Nevertheless, given their low incidence, it cannot be ruled out that they may also be largely attributed to the rejection of infants, particularly those with serious diseases. These observations can be supplemented with others related to the analysis conducted on sex ratio at birth, in order to highlight any anomalies in that relationship. Genetic, and more generally, biological factors have certainly had (and still have) an important influence in determining the changes. However, in the light of what has emerged from the data, the practice of infanticide cannot be completely ruled out when seeking an explanation for the lower than expected number of females born in specific period

Submillimetre observations of galaxy clusters with the BLAST: the star formation activity in Abell 3112

We present observations at 250, 350 and 500 μm of the nearby galaxy cluster Abell 3112 (z = 0.075) carried out with the Balloon-borne Large Aperture Submillimeter Telescope. Five cluster members are individually detected as bright submillimetre (submm) sources. Their far-infrared spectral energy distributions and optical colours identify them as normal star-forming galaxies of high mass, with globally evolved stellar populations. They all have (B−R) colours of 1.38 ± 0.08, transitional between the blue, active population and the red, evolved galaxies that dominate the cluster core. We stack to estimate the mean submm emission from all cluster members, which is determined to be 16.6 ± 2.5, 6.1 ± 1.9 and 1.5 ± 1.3 mJy at 250, 350 and 500 μm, respectively. Stacking analyses of the submm emission of cluster members reveal trends in the mean far-infrared luminosity with respect to clustercentric radius and K_(S-)band magnitude. We find that a large fraction of submm emission comes from the boundary of the inner, virialized region of the cluster, at clustercentric distances around R_(500). Stacking also shows that the bulk of the submm emission arises in intermediate-mass galaxies with K_S magnitude ~1 mag fainter than the characteristic magnitude K^*_s. The results and constraints obtained in this work will provide a useful reference for the forthcoming surveys to be conducted on galaxy clusters by Herschel

Questions on calculation of primordial power spectrum with large spikes: the resonance model case

Inflationary models predicting a scale-dependent large amplification of the density perturbations have recently attracted a lot of attention because the amplified perturbations can seed a sizable amount of primordial black holes (PBHs) and stochastic background of gravitational waves (GWs). While the power spectra in these models are computed based on the linear equation of motion, it is not obvious whether loop corrections are negligible when such a large amplification occurs during inflation. In this paper, as a first step to discuss the loop corrections in such models, we use the in-in formalism and calculate the one-loop scalar power spectrum numerically and analytically in an illustrative model where the density perturbations are resonantly amplified due to oscillatory features in the inflaton potential. Our calculation is technically new in that the amplified perturbations are numerically taken into account in the in-in formalism for the first time. In arriving at our analytical estimates, we highlight the role that the Wronskian condition of perturbations, automatically satisfied in our model, plays in obtaining the correct estimates. In addition, the analytical estimates show that the contribution originating from the quantum nature of the perturbations in the loop can be dominant. We also discuss the necessary conditions for subdominant loop corrections in this model. We find that, for the typical parameter space leading to the $\mathcal O(10^7)$ amplification of the power spectrum required for a sufficient PBH production, the one-loop power spectrum dominates over the tree-level one, indicating the breakdown of the perturbation theory.Comment: 42 pages, 15 figure

Quantitative real time PCR approach to study gene expression profile during prenatal growth of skeletal muscle in pig of Duroc and Pietrain breeds

The quantitative real time-PCR (QRT-PCR) is a very sensitive method used to quantify mRNA level in gene expression analysis. Combining amplification, detection and quantification in a single step, allows a more accurate measurement compared to the traditional PCR end point analysis (Pfaffl, 2001; Bustin, 2002)

A measurement method of routing flexibility in manufacturing systems

Article history: Received 27 January 2011 Received in revised form 25 February 2011 Accepted 2 March 2011 Available online 3 March 2011 This paper focuses on routing flexibility, which is the ability to manufacture a part type via several routes and/or to perform different operations on more than one machine. Specifically, the paper presents a comprehensive method for the measurement of routing flexibility, in a generic manufacturing system. The problem is approached in a modular way, starting from a basic set of flexibility indexes. These are progressively extended to include more comprehensive and complex routing attributes, such as: the average efficiency, the range and the homogeneous distribution of the alternative routes. Two procedures are finally proposed to compare manufacturing systems in terms of routing flexibility. The first one uses a vectorial representation of the previously defined indexes and the second one is based on data envelopment analysis, a multi-criteria decision making approach. The paper concludes with a numerical example, supported by discrete event simulation, which validates the proposed approach. © 2011 Growing Science Ltd. All rights reserve