Cosmic Constraint to DGP Brane Model: Geometrical and Dynamical Perspectives

In this paper, the Dvali-Gabadadze-Porrati (DGP) brane model is confronted by current cosmic observational data sets from geometrical and dynamical perspectives. On the geometrical side, the recent released Union2 $557$ of type Ia supernovae (SN Ia), the baryon acoustic oscillation (BAO) from Sloan Digital Sky Survey and the Two Degree Galaxy Redshift Survey (transverse and radial to line-of-sight data points), the cosmic microwave background (CMB) measurement given by the seven-year Wilkinson Microwave Anisotropy Probe observations (shift parameters $R$, $l_a(z_\ast)$ and redshift at the last scatter surface $z_\ast$), ages of high redshifts galaxies, i.e. the lookback time (LT) and the high redshift Gamma Ray Bursts (GRBs) are used. On the dynamical side, data points about the growth function (GF) of matter linear perturbations are used. Using the same data sets combination, we also constrain the flat $\Lambda$CDM model as a comparison. The results show that current geometrical and dynamical observational data sets much favor flat $\Lambda$CDM model and the departure from it is above $4\sigma$($6\sigma$) for spatially flat DGP model with(without) SN systematic errors. The consistence of growth function data points is checked in terms of relative departure of redshift-distance relation.Comment: 14 pages, 5 figures, 2 tables, accepted for publication in Physical Review

The Integrated Sachs-Wolfe Effect in Time Varying Vacuum Model

The integrated Sachs-Wolfe (ISW) effect is an important implication for dark energy. In this paper, we have calculated the power spectrum of the ISW effect in the time varying vacuum cosmological model, where the model parameter $\beta=4.407$ is obtained by the observational constraint of the growth rate. It's found that the source of the ISW effect is not only affected by the different evolutions of the Hubble function $H(a)$ and the dimensionless matter density $\Omega_m(a)$, but also by the different growth function $D_+(a)$, all of which are changed due to the presence of matter production term in the time varying vacuum model. However, the difference of the ISW effect in $\Lambda(t)\textmd{CDM}$ model and $\Lambda \textmd{CDM}$ model is lessened to a certain extent due to the integration from the time of last scattering to the present. It's implied that the observations of the galaxies with high redshift are required to distinguish the two models

AGN Environments in the Sloan Digital Sky Survey I: Dependence on Type, Redshift, and Luminosity

We explore how the local environment is related to the redshift, type, and luminosity of active galactic nuclei (AGN). Recent simulations and observations are converging on the view that the extreme luminosity of quasars is fueled in major mergers of gas-rich galaxies. In such a picture, quasars are expected to be located in regions with a higher density of galaxies on small scales where mergers are more likely to take place. However, in this picture, the activity observed in low-luminosity AGN is due to secular processes that are less dependent on the local galaxy density. To test this hypothesis, we compare the local photometric galaxy density on kiloparsec scales around spectroscopic Type I and Type II quasars to the local density around lower luminosity spectroscopic Type I and Type II AGN. To minimize projection effects and evolution in the photometric galaxy sample we use to characterize AGN environments, we place our random control sample at the same redshift as our AGN and impose a narrow redshift window around both the AGN and control targets. We find that higher luminosity AGN have more overdense environments compared to lower luminosity AGN on all scales out to our 2\Mpchseventy limit. Additionally, in the range $0.3\leqslant z\leqslant 0.6$, Type II quasars have similarly overdense environments to those of bright Type I quasars on all scales out to our 2\Mpchseventy limit, while the environment of dimmer Type I quasars appears to be less overdense than the environment of Type II quasars. We see increased overdensity for Type II AGN compared to Type I AGN on scales out to our limit of 2\Mpchseventy in overlapping redshift ranges. We also detect marginal evidence for evolution in the number of galaxies within 2\Mpchseventy of a quasar with redshift.Comment: 30 pages, 9 figures. Major revisions made for current version. Some content in previous version has been removed to refocus content on redshift and type effects. This content will be deferred to later work

Impact of sitagliptin on endometrial mesenchymal stem-like progenitor cells : a randomised, double-blind placebo-controlled feasibility trial

Background: Recurrent pregnancy loss (RPL) is associated with the loss of endometrial mesenchymal stem-like progenitor cells (eMSC). DPP4 inhibitors may increase homing and engraftment of bone marrow-derived cells to sites of tissue injury. Here, we evaluated the effect of the DPP4 inhibitor sitagliptin on eMSC in women with RPL, determined the impact on endometrial decidualization, and assessed the feasibility of a full-scale clinical trial. Methods: A double-blind, randomised, placebo-controlled feasibility trial on women aged 18 to 42 years with a history of 3 or more miscarriages, regular menstrual cycles, and no contraindications to sitagliptin. Thirty-eight subjects were randomised to either 100 mg sitagliptin daily for 3 consecutive cycles or identical placebo capsules. Computer generated, permuted block randomisation was used to allocate treatment packs. Colony forming unit (CFU) assays were used to quantify eMSC in midluteal endometrial biopsies. The primary outcome measure was CFU counts. Secondary outcome measures were endometrial thickness, study acceptability, and first pregnancy outcome within 12 months following the study. Tissue samples were subjected to explorative investigations. Findings: CFU counts following sitagliptin were higher compared to placebo only when adjusted for baseline CFU counts and age (RR: 1.52, 95% CI: 1.32–1.75, P<0.01). The change in CFU count was 1.68 in the sitagliptin group and 1.08 in the placebo group. Trial recruitment, acceptability, and drug compliance were high. There were no serious adverse events. Explorative investigations showed that sitagliptin inhibits the expression of DIO2, a marker gene of senescent decidual cells. Interpretation: Sitagliptin increases eMSCs and decreases decidual senescence. A large-scale clinical trial evaluating the impact of preconception sitagliptin treatment on pregnancy outcome in RPL is feasible and warranted. Funding: Tommy's Baby Charity. Clinical trial registration: EU Clinical Trials Register no. 2016-001120-54

Biases in Virial Black Hole Masses: An SDSS Perspective

We compile black hole (BH) masses for $\sim 60,000$ quasars in the redshift range $0.1 \lesssim z \lesssim 4.5$ included in the Fifth Data Release of the Sloan Digital Sky Survey (SDSS), using virial BH mass estimators based on the \hbeta, \MgII, and \CIV emission lines. We find that: (1) within our sample, the widths of the three lines follow log-normal distributions, with means and dispersions that do not depend strongly on luminosity or redshift;(2) the \MgII- and \hbeta-estimated BH masses are consistent with one another; and (3) the \CIV BH mass estimator may be more severely affected by a disk wind component than the \MgII and \hbeta estimators, giving a positive bias in mass correlated with the \CIV-\MgII blueshift. Most SDSS quasars have virial BH masses in the range $10^8-10^9 M_\odot$. There is a clear upper mass limit of $\sim 10^{10} M_\odot$ for active BHs at $z \gtrsim 2$, decreasing at lower redshifts. Making the reasonable assumptions that the underlying BH mass distribution decreases with mass and that the Eddington ratio distribution at fixed BH mass has non-zero width, we show that the measured virial BH mass distribution and Eddington ratio distribution are subject to Malmquist bias. A radio quasar subsample (with $1.5\lesssim z\lesssim 2.3$) has mean virial BH mass larger by $\sim 0.12$ dex than the whole sample. A broad absorption line (BAL) quasar subsample (with $1.7\lesssim z\lesssim 2.2$) has identical virial mass distribution as the nonBAL sample, with no mean offset. (Abridged)Comment: Updated virial mass measurements; improved presentation of the MC simulation; added new discussion sections; conclusions unchanged. The full table1 is available at http://www.astro.princeton.edu/~yshen/BH_mass/datafile1.txt.tar.g

A Portuguese Adaptation of the Teruel Orthorexia Scale and a Test of Its Utility with Brazilian Young Adults

The aims for this study were to perform a Portuguese language cross-cultural adaptation of the Teruel Orthorexia Scale (TOS) and to evaluate the scale's psychometric properties, including verifying the frequency of behaviors characteristic of orthorexia nervosa and healthy orthorexia, among a group of Brazilian gym users. First, we adapted the Spanish version of the TOS to the Brazilian Portuguese language following international protocols to guarantee idiomatic, semantic, conceptual, and cultural equivalence. Then participants completed both the new Portuguese version of the TOS and a socioeconomic questionnaire. Among our sample of 226 young Brazilian adults (63.7% men; M age = 28.8, SD = 5.1 years), we assessed the bi-factorial model of the TOS through factorial, convergent, and discriminant validity, reliability, and factorial invariance. We calculated the mean scores of the TOS factors and the frequency of behaviors of both orthorexia nervosa and healthy orthorexia. The new Portuguese version was well understood by participants, and the TOS bi-factorial model presented adequate psychometric properties and showed invariance in independent subsamples and in men and women. The mean scores were different between sexes only for orthorexia nervosa, with women obtaining higher values. The frequency of orthorexia nervosa behaviors was 5.3% and of healthy orthorexia was 41.2%. Based on these findings, the Brazilian Portuguese version of the TOS can be a useful tool for investigating orthorexia-like behaviors in future research.info:eu-repo/semantics/publishedVersio

A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity

(Abridged) We develop a model for the cosmological role of mergers in the evolution of starbursts, quasars, and spheroidal galaxies. Combining halo mass functions (MFs) with empirical halo occupation models, we calculate where major galaxy-galaxy mergers occur and what kinds of galaxies merge, at all redshifts. We compare with observed merger MFs, clustering, fractions, and small-scale environments, and show that this yields robust estimates in good agreement with observations. Making the simple ansatz that major, gas-rich mergers cause quasar activity, we demonstrate that this naturally reproduces the observed rise and fall of the quasar luminosity density from z=0-6, as well as quasar LFs, fractions, host galaxy colors, and clustering as a function of redshift and luminosity. The observed excess of quasar clustering on small scales is a natural prediction of the model, as mergers preferentially occur in regions with excess small-scale galaxy overdensities. We show that quasar environments at all observed redshifts correspond closely to the empirically determined small group scale, where mergers of gas-rich galaxies are most efficient. We contrast with a secular model in which quasar activity is driven by bars/disk instabilities, and show that while these modes probably dominate at Seyfert luminosities, the constraints from clustering (large and small-scale), pseudobulge populations, disk MFs, luminosity density evolution, and host galaxy colors argue that they must be a small contributor to the z>1 quasar luminosity density.Comment: 34 pages, 27 figures, submitted to ApJ. Fixed appearance of Figure

Investigating method effects associated with the wording direction of items of the Social Physique Anxiety Scale

Purpose The use of psychometric instruments to measure latent concepts is common. The development of these instruments usually involves mechanisms to reduce response bias, such as the inclusion of reversed items. The aim of this study was to investigate method efects related to the wording direction of the Social Physique Anxiety Scale (SPAS) items, a onedimensional instrument that assesses individual’s level of anxiety when others observe their body. Methods In total, 152 Brazilian adults (65.8% female) answered 2 formats of the SPAS: the original with 12 items (7 regular and 5 reversed); and a new format with all items written in the same direction (i.e., regular). Both formats were flled out at diferent times and alternately. Diferential item functioning analysis (DIF) and confrmatory factor analysis were conducted. Results The original SPAS did not ft the data, but after allowing covariances between all reversed items, the ft improved. The wording efect was supported by the DIF, indicating a better ft to the data for the new format with all items worded in the same direction. Conclusion The wording of the SPAS items had efect on the psychometric properties of instrument. When the wording of the reversed items was modifed, the factor model ftted the data. Future studies should take these fndings into account and evaluate the SPAS with all items worded in the same direction in diferent contexts. Level of evidence Descriptive (cross-sectional) study, Level V.info:eu-repo/semantics/publishedVersio

Forecasting Cosmological Constraints from Redshift Surveys

Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up of cosmological structure, which depends both on the expansion rate of the Universe and our theory of gravity. In this paper we present a formalism for forecasting the constraints on the growth of structure which would arise in an idealized survey. This Fisher matrix based formalism can be used to study the power and aid in the design of future surveys.Comment: 7 pages, 5 figures, minor revisions to match version accepted by MNRA

Differentiating dark energy and modified gravity with galaxy redshift surveys

The observed cosmic acceleration today could be due to an unknown energy component (dark energy), or a modification to general relativity (modified gravity). If dark energy models and modified gravity models are required to predict the same cosmic expansion history H(z), they will predict different growth rate for cosmic large scale structure, f_g(z)=d\ln \delta/d\ln a (\delta=(\rho_m-\bar{\rho_m})/\bar{\rho_m}), a is the cosmic scale factor). If gravity is not modified, the measured H(z) leads to a unique prediction for f_g(z), f_g^H(z). Comparing f_g^H(z) with the measured f_g(z) provides a transparent and straightforward test of gravity. We show that a simple \chi^2 test provides a general figure-of-merit for our ability to distinguish between dark energy and modified gravity given the measured H(z) and f_g(z). We study a magnitude-limited NIR galaxy redshift survey covering >10,000 (deg)^2 and the redshift range of 0.5<z<2. The resultant data can be divided into 7 redshift bins, and yield the measurement of H(z) to the accuracy of 1-2% via baryon acoustic oscillation measurements, and f_g(z) to the accuracy of a few percent via the measurement of redshift space distortions and the bias factor which describes how light traces mass. We find that if the H(z) data are fit by both a DGP gravity model and an equivalent dark energy model that predict the same expansion history, a survey area of 11,931 (deg)^2 is required to rule out the DGP gravity model at the 99.99% confidence level. It is feasible for such a galaxy redshift survey to be carried out by the next generation space missions from NASA and ESA, and it will revolutionize our understanding of the universe by differentiating between dark energy and modified gravity.Comment: 6 pages, 2 color figures. Expanded version accepted by JCA