On the shape of rotating black-holes

We give a thorough description of the shape of rotating axisymmetric stable black-hole (apparent) horizons applicable in dynamical or stationary regimes. It is found that rotation manifests in the widening of their central regions (rotational thickening), limits their global shapes to the extent that stable holes of a given area A and angular momentum J (non zero) form a precompact family (rotational stabilization) and enforces their whole geometry to be close to the extreme-Kerr horizon geometry at almost maximal rotational speed (enforced shaping). The results, which are based on the stability inequality, depend only on A and J. In particular they are entirely independent of the surrounding geometry of the space-time and of the presence of matter satisfying the strong energy condition. A complete set of relations between A, J, the length L of the meridians and the length R of the greatest axisymmetric circle, is given. We also provide concrete estimations for the distance between the geometry of horizons and that of the extreme Kerr, in terms only of A and J. Besides it own interest, the work has applications to the Hoop conjecture as formulated by Gibbons in terms of the Birkhoff invariant, to the Bekenstein-Hod entropy bounds and to study the compactness of classes of stationary black-hole space-times.Comment: Changes made to match published version in Phy. Rev.

The area-angular momentum inequality for black holes in cosmological spacetimes

For a stable marginally outer trapped surface (MOTS) in an axially symmetric spacetime with cosmological constant $\Lambda > 0$ and with matter satisfying the dominant energy condition, we prove that the area $A$ and the angular momentum $J$ satisfy the inequality $8\pi |J| \le A\sqrt{(1-\Lambda A/4\pi)(1-\Lambda A/12\pi)}$ which is saturated precisely for the extreme Kerr-deSitter family of metrics. This result entails a universal upper bound $|J| \le J_{\max} \approx 0.17/\Lambda$ for such MOTS, which is saturated for one particular extreme configuration. Our result sharpens the inequality $8\pi |J| \le A$, [7,14] and we follow the overall strategy of its proof in the sense that we estimate the area from below in terms of the energy corresponding to a "mass functional", which is basically a suitably regularised harmonic map $\mathbb{S}^2 \rightarrow \mathbb{H}^2$. However, in the cosmological case this mass functional acquires an additional potential term which itself depends on the area. To estimate the corresponding energy in terms of the angular momentum and the cosmological constant we use a subtle scaling argument, a generalised "Carter-identity", and various techniques from variational calculus, including the mountain pass theorem.Comment: 24p; minor corrections to v

Homological properties of pro-p groups

Orientador: Dessislava Hristova KochloukovaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação CientificaResumo: Nesta dissertação discutimos propriedades homológicas de grupos discretos e grupos pro-p. Em particular trabalhamos com grupos abstratos de dualidade de Poincaré orientáveis de dimensão três e seu completamento pro-p. Os primeiros capítulos da dissertação incluem uma exposição sobre as propriedades homológicas básicas de grupos abstratos e grupos pro-p. Finalmente, descrevemos um resultado recente de [KZ], publicado em Transactions MAS ( 2008), que clássica quando o completamento pro-p de um grupo de dualidade de Poincaré orientável de dimensão três de um grupo pro-p de dualidade de Poincaré orientável de dimensão trêsAbstract: In this dissertation we discuss homological properties of discrete groups and pro-p groups. In particular we work with groups of abstract of Poincaré duality of dimension three steerable and its pro-p completion. The first chapters of the dissertation include a presentation on the basic homological properties of abstract groups and pro-p groups. Finally, we describe a recent result of [KZ], published in Transactions AMS (2008), which ranks as the pro-p completion of a group of Poincare-steerable dual dimension of three is a group of pro-p duality of Poincare -steerable in three dimensionsMestradoMestre em Matemátic

Effect of Support Properties on Selective Butanediols Production from Erythritol using Ir/ReOx Catalysts

This study reports the selective obtaining of butanediols (BDO), widely used in the polymer and synthetic rubber industry, by C−O hydrogenolysis of erythritol. The effect of the support on catalytic activity and selectivity to BDO was exhaustively studied using Ir/ReOx catalysts supported on SiO2, Al2O3, activated carbon, CeO2, TiO2 and ZrO2. The catalysts were thoroughly characterized and it was found that the physicochemical, redox and acidic properties of the supports notably influenced the metal dispersion, reducibility of the species and particle sizes. The most active and selective catalyst was Ir/ReOx/TiO2 (maximum BDO yield of 53 %), favoring C−O hydrogenolysis and minimizing C−C scissions and dehydration reactions. This superior performance was attributed to the formation of small clusters with an intimate contact between Ir and partially oxidized Re species (mainly Re+IV) that favors the appropriate adsorption of erythritol on ReO2 and the further interaction with H2 adsorbed on Ir0 to render BDO.Fil: Virgilio, Emanuel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Padro, Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Sad, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentin

Butanediols production from erythritol on Rh promoted catalyst

The C-O hydrogenolysis of Erythritol to Butanodiols was studied in aqueous solution at 473 K and 25 bar of H2 using Rh/ReOx/TiO2 and the monometallic Rh/TiO2 and ReOx/TiO2 catalysts. The solids were characterized by temperature programmed reduc-tion (TPR), TEM and XPS. TPR and XPS showed that ReOx species are close to Rh particles leading to reduction at lower temperature than Re on mono-metallic catalyst. However, some segregated Rhenium species were suspected by TPR profile for the bimetallic catalyst and detected by TEM. Re/TiO2 exhibited low activity forming only products from dehydration and epimerization. Although Rh/TiO2 showed high activity (total conversion at 14 h), was more selective to C-C cleavage leading to lower car-bon products. Rh/ReOx/TiO2, showed instead, a good activity and selectivity towards C-O hydrogenolysis route yielding 37.5% of Butanodiols. Activation en-ergy and reaction orders on ERY (0.58) and H2 (0.53) were estimated from experiences made at dif-ferent reaction conditions.Fil: Virgilio, Emanuel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Padro, Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Sad, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentin

Le déclin cognitif dans la maladie d'Alzheimer

Les travaux sur l'histoire naturelle de la maladie d'Alzheimer (MA) ont souligné que le mode et la vitesse du déclin cognitif au cours de la maladie étaient très variables selon les patients. L'étude des patients ayant un déclin cognitif rapide (DCR) mérite une attention particulière en raison de leur prévalence non négligeable et de leur pronostic plus péjoratif. En pratique clinique, c'est important de repérer les patients à risque de DCR le plus précocement possible afin d'anticiper une prise en charge plus adaptée pour ce groupe des patients. En l'absence de traitements curatifs, les enjeux de la recherche épidémiologique dans la MA sont essentiellement basés sur la prévention et le ralentissement de son évolution. Objectifs : Ce travail de thèse comporte deux objectifs généraux : 1) étudier le déclin cognitif rapide dans la MA: pronostic, définition, trajectoire et facteurs de risque ; 2) étudier des facteurs modifiables du déclin cognitif faciles à implémenter dans la pratique clinique: la perte de poids et le traitement par les inhibiteurs de l'enzyme de conversion de l'Angiotensine (IECs). Méthodes : Afin de répondre à ces objectifs, deux populations des patients atteints d'une MA à un stade léger à modéré ont été étudiées à l'issue de la cohorte Française REAL.FR et de la cohorte européenne ICTUS. Résultats : Les résultats majeurs de ce travail de thèse sont que les patients ayant un DCR, définit par une perte de = 4 points au MMSE durant 6 mois, présentent une augmentation significative du risque de mortalité (HR = 5,6, 95% CI 2,0-15,9), d'institutionnalisation (HR = 3,8, 95% CI 1,8-8,1) et de perte d'autonomie fonctionnelle (HR = 1,6, 95% CI 1,2-2,3) à 18 mois de suivi. Deux types de profils parmi les patients ayant un DCR ont été identifiés : 1) ceux avec un DCR " persistant " dans le temps (12%) et 2) ceux avec un déclin cognitif " réversibles " (21%). Le cluster " déclineurs rapides persistants " présente une perte annuelle de 5,5 points au MMSE. Les variables associées à un risque accru de DCR sont liées au mode de vie (seul à domicile), à un statut cognitif et fonctionnel plus altérés à l'inclusion et à l'absence d'hypertension. Dès le stade léger du déficit, tous les items de l'ADAS-cog explorant le langage (HR =2,8, 95%IC =1,7-4,5) sont des facteurs prédictifs indépendants d'un DCR de même que les items " Exécution d'ordres" (HR=1,9, 95%IC =1,9-4,3) et " Praxies constructives " (HR=2,8, 95%IC =1,9-4,3) à 2 ans de suivi. Ces résultats ont permis de distinguer un profil d'atteinte cognitive particulière prédictif d'un DCR. Ces résultats suggèrent que les patients atteints d'une MA avec DCR pourraient presenter une forme particulière et distincte de MA. Les résultats répondant au deuxième objectif général de ce travail de thèse démontrent que la perte de poids est un facteur prédictif de DCR (HR= 1,58, 95%IC = 1,14-2,21) et que la consommation des IECs est associée, indépendamment de la hypertension, à un moindre déclin cognitif à 4 ans de suivi par rapport aux ceux qui n'en ont jamais consommés (-7,5 points au MMSE ± 0,9 vs. -9,7 ± 0,4; p = 0,03).The rate of cognitive decline in Alzheimer's disease (AD) varies considerably between individuals. The assessment of how rapidly the disease is progressing has important implications in clinical practice and for care planification, since patients presenting with rapid cognitive decline (RCD) are frequent and have a poorer prognosis. Therefore, their early identification is essential. In the absence of a curative treatment for AD, the current challenge of the epidemiologic research is based on the prevention and on slowing down the progression of the disease. Objectives: This thesis has two general aims: 1) To study RCD in AD: prognostic, definition, trajectory and risk factors and a psychometric profile. 2) To study potential modifiable factors in affecting cognitive decline, and easy to be implemented in clinical practice: weight loss and the treatment by angiotensin-converting enzyme inhibitors (ACE-Is). Methods: In order to answer to our objectives, two populations of mild to moderate AD community-dwelling patients have been assessed from the multicenter French cohort REAL.FR and the multicenter European cohort ICTUS. Results: The main results of the this work are that patients with a RCD, defined as a loss of = 4 points in MMSE during 6 months, showed a significantly increased risk of mortality (HR = 5.6, 95% CI 2.0-15.9), risk of physical decline (HR = 1.6, 95% CI 1.2-2.3) and institutionalization (HR = 3.8, 95% CI 1.8-8.1) at the 2-year follow-up. Two types of profile of patients with RCD (~30%) have been identified: 1) those classified as either "temporary" (~21%) and 2) those as "continuous" (~12%). The cluster " continuous rapid decliners " presented a yearly loss of 5,5 points in MMSE. Living alone, lower cognitive level at entry into the study, greater loss of autonomy and the absence of hypertension were associated with a higher risk of RCD. Early language impairments assessed by ADAS-cog sub-scales are predictors of future RCD (HR =2,8, 95%IC =1,7-4,5), as well as for "Commands" (HR=1,9, 95%IC =1,9-4,3) and "Constructional praxis" (HR=2,8, 95%IC =1,9-4,3) at 2 years of follow-up. These results allowed identifying a particular psychometric profile of RCD. All these previous results could suggest that AD with RCD represent an AD sub-type with a distinct entity. The main results of the second part of this thesis show that weight loss is an independent predictor factor of RCD (HR= 1,58, 95%IC = 1,14-2,21) and that the use of ACE-s is associated, independently of hypertension at each visit, with a slower cognitive decline: participants who had continuously or intermittently used ACE-Is had a significant difference in 4-year MMSE decline from those who had never used ACE-Is (-7,5 points au MMSE ± 0,9 vs. -9,7 ± 0,4; p = 0,03)

Efficacy of Essential Oils of Thymus vulgaris and Origanum vulgare on Echinococcus granulosus

The aim of the present work was to determine the in vitro effect of T. vulgaris and O. vulgare essential oils against E. granulosus protoscoleces and cysts. Essential oils were added to the medium resulting in thymol final concentrations of 10 μg/mL. The essential oils had a time-dependent effect provoking the complete loss of protoscolex viability after 72 days of postincubation. The results were confirmed at the ultrastructure level. Loss of infectivity in protoscoleces incubated with O. vulgare after 60 days was observed. On the other hand, the weight of cysts recorded in mice inoculated with T. vulgaris treated protoscoleces was significantly lower than that obtained in control group. Gamma-glutamyl-transpeptidase activity was readily detected in the culture supernatant of protoscoleces treated either with the essential oils or thymol. T. vulgaris and O. vulgare essential oils and thymol can induce cell apoptosis of protoscoleces after short incubation times. The efficacy of T. vulgaris and O. vulgare essential oils was also demonstrated in vitro on E. granulosus murine cysts. Our data suggest that essential oils of T. vulgaris and O. vulgare have anthelmintic effect against protoscoleces and cysts of E. granulosus.Fil: Pensel, Patricia Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Maggiore, Marina Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Gende, Liesel Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Artrópodos; ArgentinaFil: Eguaras, Martin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Artrópodos; ArgentinaFil: Denegri, Guillermo Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Elissondo, María Celina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; Argentin

Strategies and approaches in plasmidome studies, uncovering plasmid diversity disregarding of linear elements?

The term plasmid was originally coined for circular, extrachromosomal genetic elements. Today, plasmids are widely recognised not only as important factors facilitating genome restructuring but also as vehicles for the dissemination of beneficial characters within bacterial communities. Plasmid diversity has been uncovered by means of culture dependent or independent approaches, such as endogenous or exogenous plasmid isolation as well as PCR-based detection or transposon-aided capture, respectively. High-throughput-sequencing made possible to cover total plasmid populations in a given environment, i.e. the plasmidome, and allowed to address the quality and significance of self-replicating genetic elements. Since such efforts were and still are rather restricted to circular molecules, here we put equal emphasis on the linear plasmids which despite their frequent occurrence in a large number of bacteria are largely neglected in prevalent plasmidome conceptions.Fil: Dib, Julian Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; ArgentinaFil: Wagenknecht, Martin. Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster.; AlemaniaFil: Farias, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; ArgentinaFil: Meinhardt, Friedhelm. Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster.; Alemani

Targeting organogenesis and beta cell survival: role of the LRH1/NR5A2-PTGS2/COX2 signaling axis in pancreatic islet physiology and pathophysiology

Programa de Doctorado en Biotecnología, Ingeniería y Tecnología QuímicaLínea de Investigación: Biotecnología, Biomedicina y Ciencias de la SaludClave Programa: DBICódigo Línea: 110Type 1 Diabetes Mellitus (T1DM) is a disease caused by the selective destruction of pancreatic islet beta cells by aberrant activation of the immune system, characterized by a subsequent chronic unresolved proinflammatory status within the pancreas. Up to date, no effective therapies have been developed to cure this autoimmune disorder, which indeed, apart from the beta cell death and subsequent lack of insulin, leads to long-term complications that substantially impact on life quality and shorten life expectancy. However, our laboratory recently reported promising outcomes from the in vivo activation of a nuclear receptor, denoted as Liver Receptor Homolog 1 (also known as (a.k.a.) Nuclear Receptor Subfamily 5 Group A Member 2, LRH1/NR5A2), using different preclinical mouse models of autoimmune diabetes, and also in vitro, by mimicking the stress/proinflammatory conditions that characterize T1DM in both, mouse and human primary islet-cell cultures. These beneficial effects derived from the treatment with a chemical agonist of LRH1/NR5A2, codename BL001, which potentially favoured a crosstalk between the immune system and islet cells, aimed at protecting the beta cell mass via increasing its survival. Understanding the molecular signaling and consequences derived from LRH1/NR5A2 expression and activation in beta cells was the following step to exploit its therapeutic value within T1DM conditions. In this Thesis, we first uncovered the essential role of LRH1/NR5A2 expression in beta cells during neonatal development. We found that the LRH1/NR5A2 constitutive ablation in the beta cell mass caused a significant reduction of this cell type, mainly characterized by blunted proliferation, along with detrimental consequences in the metabolic and physical health of mouse pups that culminated in early death. We next demonstrated that the LRH1/NR5A2 specific activation in beta cells was the responsible of the beneficial effects observed in vivo, after BL001 treatment. Using an inducible approach, LRH1/NR5A2 ablation in adult beta cells abolished the protective effect of BL001 in streptozotocin (STZ)-treated mice, correlating with an almost complete beta cell mass destruction. In order to get insight into the mode of action of this potential anti-diabetic drug in beta cells, we next explored the molecular branches of the BL001-LRH1/NR5A2 axis, focusing on the inducible Prostaglandin Endoperoxidase Synthase-2 gene (a.k.a. Cyclooxygenase-2, Ptgs2/Cox2), previously shown to be upregulated by BL001, and which plays a role in immunomodulation. Ptgs2/Cox2 downstream signaling involves the secretion of Prostaglandin E2 (PGE2) and activation of one or several Prostaglandin G-protein coupled receptors (a.k.a. E-Prostanoid receptors, PTGERs/EPs). We found that mouse islets treated in vitro with BL001 upon a proinflammatory cytokine (CTK) challenge produced PGE2 massively. Importantly, both silencing of Ptgs2/Cox2 gene or downstream blockade of the anti-apoptotic PTGER1/EP1 receptor negated BL001-mediated increased islet-cell survival upon the CTK treatment, establishing the molecular survival signaling axis in mouse beta cells as follows: BL001-LRH1/NR5A2-Ptgs2/Cox2-PGE2-PTGER1/EP1. In parallel, we uncovered the deleterious role of the pro-apoptotic PTGER3/EP3 in an in vivo context, using the RIP-B7.1 mouse model of autoimmune diabetes. We found that PTGER3/EP3 antagonism reduced insulitis and protected the beta cell mass in these animals. Finally, as a future therapy for T1DM, it was mandatory to translate our survival cascade to a human setting. As such, we successfully recapitulated part of this pathway in human induced-Pluripotent Stem Cells (hiPSCs) derived islet-like organoids. This research work provides a complete molecular characterization of LRH1/NR5A2 activation specifically in the beta cell mass, which could be further fine-tuned to finally develop a successful therapy for T1DM.Universidad Pablo de Olavide de Sevilla. Departamento de Biología Molecular e Ingeniería Bioquímic