Observational constraints on the linear fluctuation growth rate

Several experiments in the near future will test dark energy through its effects on the linear growth of matter perturbations. It is therefore important to find simple and at the same time general parametrizations of the linear growth rate. We show that a simple fitting formula that generalizes previous expressions reproduces the growth function in models that allow for a growth faster than standard, as for instance in scalar-tensor models. We use data from galaxy and Lyman-$\alpha$ power spectra to constrain the linear growth rate. We find $\gamma=0.6_{-0.3}^{+0.4}$ for the growth rate index and $\eta=0.0_{-0.2}^{+0.3}$ for the additional growth parameter we introduce.Comment: 9 page

Simultaneous constraints on bias, normalization and growth index through power spectrum measurements

In this Letter we point out that redshift surveys can break the degeneracy between the galaxy bias, the power spectrum normalization, \sigma_{8,0} and the growth factor, without the need for external information by using a simple and rather general parametrization for the growth rate, the well known \gamma-parametrization and measuring the power spectrum at least at two different redshifts. We find that in next-generation surveys like Euclid, \sigma_{8,0} and \gamma can be measured to within 1% and 5%, respectively, while the bias b(z) can be measured to within 1-2% in each of 14 equal-width redshift bins spanning 0.7<=z<=2.Comment: 6 pages, 4 figures, version matching the one published by MNRAS Letter

Growth factor and galaxy bias from future redshift surveys: a study on parametrizations

Many experiments in the near future will test dark energy through its effects on the linear growth of matter perturbations. In this paper we discuss the constraints that future large-scale redshift surveys can put on three different parameterizations of the linear growth factor and how these constraints will help ruling out different classes of dark energy and modified gravity models. We show that a scale-independent bias can be estimated to a few percent per redshift slice by combining redshift distortions with power spectrum amplitude, without the need of an external estimation. We find that the growth rate can be constrained to within 2-4% for each $\Delta z=0.2$ redshift slice, while the equation of state $w$ and the index $\gamma$ can be simultaneously estimated both to within 0.02. We also find that a constant dimensionless coupling between dark energy and dark matter can be constrained to be smaller than 0.14.Comment: 22 pages, 11 figure

Growth of cosmological perturbations in Dark Energy universes

In this thesis I focused my attention on dark energy, the mysterious responsible of the observed accelerated expansion rate of our universe. Since the various different models of dark energy are degenerated respect to the observable related only to the expansion history of the universe, I have studied their predictions on the growth of linear perturbations, which provides an additional observable useful to remove the existent degeneracy. However, I found that the actual data related to the growth factor, such as the matter power spectrum from Lyman alpha forests and from 2dF galaxies, the redshift distortion and the baryonic acoustic oscillations cannot put tight constraints on the models, since the errors are still too large. The main models studied in this work are the "coupling model", where dark energy is represented by a scalar field coupled to matter, f(R) models and Dvali-Gabadadze-Porrati model, a class of theories which try to explain the accelerated expansion through modification of standard Einstein gravity. They all give very different predictions for the growth of perturbations with respect to the standard LambaCDM model thus providing a way to discriminate them. Since many experiments in the near future will test dark energy, with unprecedented precision, through its effects on the linear growth of matter perturbations, it is therefore important to find simple yet general parametrizations of the linear growth rate. I showed that a simple fitting formula that generalizes previous expressions reproduces the growth function in models that allow for a growth faster than standard, as for instance in the interacting or scalar-tensor models. This kind of parametrizations turns out to be a very useful tool when one tries to compare the model to observational data. Then I also have parametrized the growth in a large class of models, such as the f(R). The thesis also includes forecasts on the constraints that future data, coming both from satellite or ground based surveys, will put on cosmological parameters such as the growth rate. I used a Fisher matrix approach, using as observable data the information contained in the matter power spectrum, included the one coming from baryonic acoustic oscillations. I found that the improvement in constraining the parameters should be as great as to distinguish among different models

Il legame interrotto di Clara: dal trauma della migrazione alla costruzione di un contesto di integrazione e riconciliazione

La migrazione ed il ricongiungimento familiare sono delle fasi molto delicate del ciclo vitale di una famiglia immigrata che se da un lato rappresentano opportunità e risorse, dall’altro possono mettere a rischio creando una frattura nella continuità temporale tra il prima ed il dopo dell’esperienza migratoria. Il clinico che incontra a vario titolo una famiglia straniera ha bisogno, per comprenderla, di includere la cultura nei propri presupposti teorici e di costruire un contesto di incontro che legittimi l’altro rispetto alla propria appartenenza culturale. Obiettivo e Metodologia: In questo lavoro viene presentato l’intervento terapeutico riguardante una famiglia marocchina “maltrattata” con l’obiettivo di illustrare alcune problematiche che possono mettere a rischio i minori stranieri, presentandovi allo stesso tempo una possibile modalità di intervento. La cornice metodologica dell’intervento si rifà in generale alle teorie sistemiche ed in particolare al modello di lavoro con le famiglie straniere della Fondazione Silvano Andolfi costruito in 17 anni di esperienza. Conclusioni: L’intervento terapeutico con le famiglie straniere è quasi sempre fondato su un processo di integrazione. Richiede un pensiero clinico flessibile, rispettoso e curioso verso le appartenenze culturali e finalizzato a restituire competenza alle famiglie

Current patterns of beta-blocker prescription in cardiac amyloidosis: an Italian nationwide survey

Aims The use of beta-blocker therapy in cardiac amyloidosis (CA) is debated. We aimed at describing patterns of beta-blocker prescription through a nationwide survey.Methods and results From 11 referral centres, we retrospectively collected data of CA patients with a first evaluation after 2016 (n = 642). Clinical characteristics at first and last evaluation were collected, with a focus on medical therapy. For patients in whom beta-blocker therapy was started, stopped, or continued between first and last evaluation, the main reason for beta-blocker management was requested. Median age of study population was 77 years; 81% were men. Arterial hypertension was found in 58% of patients, atrial fibrillation (AF) in 57%, and coronary artery disease in 16%. Left ventricular ejection fraction was preserved in 62% of cases, and 74% of patients had advanced diastolic dysfunction. Out of the 250 CA patients on beta-blockers at last evaluation, 215 (33%) were already taking this therapy at first evaluation, while 35 (5%) were started it, in both cases primarily because of high-rate AF. One-hundred-nineteen patients (19%) who were on beta-blocker at first evaluation had this therapy withdrawn, mainly because of intolerance in the presence of heart failure with advanced diastolic dysfunction. The remaining 273 patients (43%) had never received beta-blocker therapy. Beta-blockers usage was similar between CA aetiologies. Patients taking vs. not taking beta-blockers differed only for a greater prevalence of arterial hypertension, coronary artery disease, AF, and non-restrictive filling pattern (P < 0.01 for all) in the former group.Conclusions Beta-blockers prescription is not infrequent in CA. Such therapy may be tolerated in the presence of co-morbidities for which beta-blockers are routinely used and in the absence of advanced diastolic dysfunction

Vascular Access in Patients With Peripheral Arterial Disease Undergoing TAVR: The Hostile Registry

Background: The optimal access route in patients with severe peripheral artery disease (PAD) undergoing transcatheter aortic valve replacement (TAVR) remains undetermined. Objectives: This study sought to compare clinical outcomes with transfemoral access (TFA), transthoracic access (TTA), and nonthoracic transalternative access (TAA) in TAVR patients with severe PAD. Methods: Patients with PAD and hostile femoral access (TFA impossible, or possible only after percutaneous treatment) undergoing TAVR at 28 international centers were included in this registry. The primary endpoint was the propensity-adjusted risk of 30-day major adverse events (MAE) defined as the composite of all-cause mortality, stroke/transient ischemic attack (TIA), or main access site–related Valve Academic Research Consortium 3 major vascular complications. Outcomes were also stratified according to the severity of PAD using a novel risk score (Hostile score). Results: Among the 1,707 patients included in the registry, 518 (30.3%) underwent TAVR with TFA after percutaneous treatment, 642 (37.6%) with TTA, and 547 (32.0%) with TAA (mostly transaxillary). Compared with TTA, both TFA (adjusted HR: 0.58; 95% CI: 0.45-0.75) and TAA (adjusted HR: 0.60; 95% CI: 0.47-0.78) were associated with lower 30-day rates of MAE, driven by fewer access site–related complications. Composite risks at 1 year were also lower with TFA and TAA compared with TTA. TFA compared with TAA was associated with lower 1-year risk of stroke/TIA (adjusted HR: 0.49; 95% CI: 0.24-0.98), a finding confined to patients with low Hostile scores (Pinteraction = 0.049). Conclusions: Among patients with PAD undergoing TAVR, both TFA and TAA were associated with lower 30-day and 1-year rates of MAE compared with TTA, but 1-year stroke/TIA rates were higher with TAA compared with TFA

Cosmology and Fundamental Physics with the Euclid Satellite

Euclid is a European Space Agency medium-class mission selected for launch in 2019 within the Cosmic Vision 2015-2025 program. The main goal of Euclid is to understand the origin of the accelerated expansion of the universe. Euclid will explore the expansion history of the universe and the evolution of cosmic structures by measuring shapes and red-shifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid's Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission