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

Role of B Cell Profile for Predicting Secondary Autoimmunity in Patients Treated With Alemtuzumab

UDHEBRONTo explore if baseline blood lymphocyte profile could identify relapsing remitting multiple sclerosis (RRMS) patients at higher risk of developing secondary autoimmune adverse events (AIAEs) after alemtuzumab treatment. Multicenter prospective study including 57 RRMS patients treated with alemtuzumab followed for 3.25 [3.5-4.21] years, (median [interquartile range]). Blood samples were collected at baseline, and leukocyte subsets determined by flow cytometry. We had additional samples one year after the first cycle of alemtuzumab treatment in 39 cases. Twenty-two patients (38.6%) developed AIAEs during follow-up. They had higher B-cell percentages at baseline (p=0.0014), being differences mainly due to plasmablasts/plasma cells (PB/PC, p=0.0011). Those with no AIAEs had higher percentages of CD4+ T cells (p=0.013), mainly due to terminally differentiated (TD) (p=0.034) and effector memory (EM) (p=0.031) phenotypes. AIAEs- patients also showed higher values of TNF-alpha-producing CD8+ T cells (p=0.029). The percentage of PB/PC was the best variable to differentiate both groups of patients. Baseline values >0.10% closely associated with higher AIAE risk (Odds ratio [OR]: 5.91, 95% CI: 1.83-19.10, p=0.004). When excluding the 12 patients with natalizumab, which decreases blood PB/PC percentages, being the last treatment before alemtuzumab, baseline PB/PC >0.1% even predicted more accurately the risk of AIAEs (OR: 11.67, 95% CI: 2.62-51.89, p=0.0007). The AIAEs+ group continued having high percentages of PB/PC after a year of alemtuzumab treatment (p=0.0058). A PB/PC percentage <0.1% at baseline identifies MS patients at low risk of secondary autoimmunity during alemtuzumab treatment.

The growth of matter perturbations in some scalar-tensor DE models

We consider asymptotically stable scalar-tensor dark energy (DE) models for which the equation of state parameter $w_{DE}$ tends to zero in the past. The viable models are of the phantom type today, however this phantomness is milder than in General Relativity if we take into account the varying gravitational constant when dealing with the SNIa data. We study further the growth of matter perturbations and we find a scaling behaviour on large redshifts which could provide an important constraint. In particular the growth of matter perturbations on large redshifts in our scalar-tensor models is close to the standard behaviour $\delta_m \propto a$, while it is substantially different for the best-fit model in General Relativity for the same parametrization of the background expansion. As for the growth of matter perturbations on small redshifts, we show that in these models the parameter $\gamma'_0\equiv \gamma'(z=0)$ can take absolute values much larger than in models inside General Relativity. Assuming a constant $\gamma$ when $\gamma'_0$ is large would lead to a poor fit of the growth function $f$. This provides another characteristic discriminative signature for these models.Comment: 13 pages, 7 figures, matches version published in JCA

Severe encephalopathy associated to pyruvate dehydrogenase mutations and unbalanced coenzyme Q10 content

Coenzyme Q(10) (CoQ(10)) deficiency is associated to a variety of clinical phenotypes including neuromuscular and nephrotic disorders. We report two unrelated boys presenting encephalopathy, ataxia, and lactic acidosis, who died with necrotic lesions in different areas of brain. Levels of CoQ(10) and complex II+III activity were increased in both skeletal muscle and fibroblasts, but it was a consequence of higher mitochondria mass measured as citrate synthase. In fibroblasts, oxygen consumption was also increased, whereas steady state ATP levels were decreased. Antioxidant enzymes such as NQO1 and MnSOD and mitochondrial marker VDAC were overexpressed. Mitochondria recycling markers Fis1 and mitofusin, and mtDNA regulatory Tfam were reduced. Exome sequencing showed mutations in PDHA1 in the first patient and in PDHB in the second. These genes encode subunits of pyruvate dehydrogenase complex (PDH) that could explain the compensatory increase of CoQ(10) and a defect of mitochondrial homeostasis. These two cases describe, for the first time, a mitochondrial disease caused by PDH defects associated with unbalanced of both CoQ(10) content and mitochondria homeostasis, which severely affects the brain. Both CoQ(10) and mitochondria homeostasis appears as new markers for PDH associated mitochondrial disorders

Iconographie du quotidien dans l’art provincial romain : modèles régionaux

Ce volume rassemble une grande partie des communications qui ont été présentées lors du XIVe congrès international d'art provincial romain, qui s'est tenu à Dijon (Bourgogne) du 1er au 6 juin 2015, sur le thème Iconographie du quotidien dans l'art provincial romain : modèles régionaux. Traitant d'une thématique qui jusque-là n'avait pas été évoquée dans le cadre des précédents congrès, il s'inscrit dans la continuité d'une réflexion portant sur la sculpture romaine issue des provinces. Rassemblés en quatre parties, les textes proposés par des chercheurs venant de toute l'Europe, mais aussi d'Afrique du Nord, évoquent les stèles, reliefs, sculptures qui racontent la vie quotidienne des populations de l'Empire romain, le plus souvent figurée sur des monuments funéraires. Sont ainsi évoqués la formation des enfants, divers métiers d'artisans ou de boutiquiers, les loisirs... : ces scènes sont autant de « saisies sur le vif » de ce quotidien qui nous échappe trop souvent et auquel les sources littéraires prêtent en général peu attention. Ces représentations, la nature des thématiques et des modalités d'exécution sont très liées au contexte de réalisation : le choix des ateliers, leurs pratiques en fonction des ressources locales permettent de mettre en évidence des différences perceptibles d'une région à l'autre au sein du vaste Empire romain. Une place particulière a été faite aux découvertes récentes et à l'exposition Pax Romana - Scènes du quotidien en Gaule romaine, au musée archéologique de Dijon, qui accompagnait la réunion scientifique. Abondamment illustré, ce volume offre un large panorama de la vie quotidienne des sujets de l'Empire, depuis la conquête de leur territoire jusqu'à la christianisation de l'espace romain.Dieser Band beinhaltet einen Großteil der Beiträge die auf dem XIVe congrès international d'art provincial romain (1.-6. Juni 2015 Dijon, Departement Bourgogne) zum Thema Ikonographie des Alltags in der provinzialrömischen Kunst : regionale Muster vorgestellt wurden. Er behandelt ein Thema, das in den vorangegangenen Kongressen nicht angesprochen wurde und knüpft an eine Betrachtung der römischen Skulptur aus den Provinzen an. In vier Abschnitten behandeln die Beiträge der Forscher aus ganz Europa und Nordafrika die Grabstelen, Reliefs und Skulpturen, die von dem sehr oft auf den Grabmonumenten dargestellten Alltag der Bevölkerungen im römischen Reich erzählen. Die Szenen behandeln Themen wie Schulbildung, Handels- und Handwerksberufe, Freizeit... : „aus dem Leben gegriffene Szenen" des Alltags, von dem wir nur selten eine genaue Vorstellung haben, und dem die literarischen Quellen im Allgemeinen nur wenig Aufmerksamkeit widmen. Diese Darstellungen, die Themen und deren Ausführungen stehen in enger Beziehung mit dem Kontext ihrer Realisierung : die Wahl der Werkstätten und die von den lokalen Quellen abhängigen Techniken erlauben es Unterschiede aufzuzeigen, die in diesem großen Reich zwischen den Provinzen erkennbar sind. Ein besonderer Platz wurde den neueren Entdeckungen eingeräumt sowie der Ausstellung Pax Romana - Scènes du quotidien en Gaule romaine im archäologischen Museum von Dijon, die den Kongress begleitete. Der vorliegende reich bebilderte Band bietet einen Überblick über den Alltag der Untertanen des römischen Reiches von der Eroberung ihres jeweiligen Territoriums bis zur Christianisierung