Data Management and Mining in Astrophysical Databases

We analyse the issues involved in the management and mining of astrophysical data. The traditional approach to data management in the astrophysical field is not able to keep up with the increasing size of the data gathered by modern detectors. An essential role in the astrophysical research will be assumed by automatic tools for information extraction from large datasets, i.e. data mining techniques, such as clustering and classification algorithms. This asks for an approach to data management based on data warehousing, emphasizing the efficiency and simplicity of data access; efficiency is obtained using multidimensional access methods and simplicity is achieved by properly handling metadata. Clustering and classification techniques, on large datasets, pose additional requirements: computational and memory scalability with respect to the data size, interpretability and objectivity of clustering or classification results. In this study we address some possible solutions.Comment: 10 pages, Late

Is now the time for molecular driven therapy for diffuse large B-cell lymphoma?

INTRODUCTION: Recent genetic and molecular discoveries regarding alterations in diffuse large B-cell lymphoma (DLBCL) deeply changed the approach to this lymphoproliferative disorder. Novel additional predictors of outcomes and new therapeutic strategies are being introduced to improve outcomes. Areas covered: This review aims to analyse the recent molecular discoveries in DLBCL, the rationale of novel molecular driven treatments and their impact on DLBCL prognosis, especially in ABC-DLBCL and High Grade B Cell Lymphoma. Pre-clinical and clinical evidences are reviewed to critically evaluate the novel DLBCL management strategies. Expert commentary: New insights in DLBCL molecular characteristics should guide the therapeutic approach; the results of the current studies which are investigating safety and efficacy of novel 'X-RCHOP' will probably lead, in future, to a cell of origin (COO) based upfront therapy. Moreover, it is necessary to identify early patients with DLBCL who carried MYC, BCL2 and/or BCL6 rearrangements double hit lymphomas (DHL) because they should not receive standard R-CHOP but high intensity treatment as reported in many retrospective studies. New prospective trials are needed to investigate the more appropriate treatment of DHL

Characterization and selective manipulation of GnRHR-expressing neurons in the periaqueductal gray of female mice (Mus musculus, Linnaeus 1758)

The gonadotropin-releasing hormone (GnRH) is the main regulator of reproductive physiology in vertebrates. GnRH is released by a small subset of hypothalamic neurons. In the pituitary gland it acts on gonadotropes, which selectively express the Gonadotropin-releasing hormone receptor (GnRHR). The GnRHR signal in gonadotrope cells is then crucial for gonadal function and thus fertility. Furthermore, classical studies in rats indicated that GnRH strongly facilitates female sexual behavior, by acting directly in the brain. In particular, GnRH infusions within the dorsal periaqueductal gray (PAG) augmented female sexual receptivity. Previously our lab has generated a mouse model that allowed for the reliable visualization of the neural targets of GnRH, via Cre-dependent expression of τGFP in GnRHR-expressing cells. GnRHR neurons are widely present in the male mouse brain in areas involved in sex-specific behaviors, including the PAG. Furthermore, GnRH could elicit calcium responses and modulate firing activity in GnRHR neurons. However, the role of GnRHR neurons in behavior remained unexplored. By using the same binary genetic approach, I first aimed to describe the GnRHR network in the PAG of the female mouse in age-matched groups. I found a wide distribution of GnRHR neurons specifically in the dorsal and lateral parts of the PAG, but not in the ventrolateral PAG. Furthermore, the number of GnRHR neurons increased during age, suggesting a late establishment of the GnRHR network within the PAG. Secondly, I aimed to genetically ablate GnRHR neurons in the dorsal PAG. In order to do that, I injected in the dorsal PAG an adeno-associated virus that mediates cre-dependent expression of a constitutively active form of caspase-3. In this way, I could induce programmed cell death only in PAG-GnRHR neurons. Surprisingly, ablation did not affect female sexual receptivity. Moreover, I investigated GnRHR neural activity following female sexual behavior by using the marker c-fos. I found a strong c-fos up-regulation in the PAG, but not in GnRHR neurons. In a parallel study I have explored the role of metabotropic glutamate receptor 5 (mGluR5) in the initiation of puberty. The neuroendocrine mechanisms that regulate the initiation of puberty have been largely explored but still poorly understood. Evidence revealed a role of glutamate in the regulation of GnRH neurons. Female VII mice lacking the metabotropic receptor 5 (mGluR5) gene exhibited delayed puberty and reduced fertility. To analyze gonadotropin function in the absence of mGluR5 I analyzed the whole pituitary hormone serum profiles. I found reduced levels of follicle stimulating hormone but not luteinizing hormone, together with higher thyroid-stimulating hormone levels in female mice lacking the mGluR5 gene. These results could provide new insights into the mechanisms that can regulate fertility and help to develop new therapies for puberty disorders.Das Gonadotropin-freisetzendes Hormon (GnRH) ist der Hauptregler der Fortpflanzungsphysiologie bei Wirbeltieren. GnRH wird von einer kleinen Untergruppe von Hypothalamus Neuronen freigesezt. In die Hypophyse es auf gonadotrope zellen wirkt, die selektiv den Gonadotropin freisetzenden Hormonrezeptor (GnRHR) exprimieren. Das GnRHR-Signal in den gonadotrope zellen ist dann entscheidend für die Gonadenfunktion und damit die Fruchtbarkeit. Darüber hinaus haben klassische Studien an Ratten gezeigt, dass GnRH das weibliche Sexualverhalten fördert, da es direkt im Gehirn wirkt. Insbesondere verstärken GnRH-Infusionen im dorsalen periaqueduktalen Grau (PAG) die weibliche sexuelle Empfänglichkeit. Zuvor wurde in unserem Labor ein Mausmodell erzeugt, dass die zuverlässige Visualisierung der neuronalen Ziele von GnRH über Cre-abhängige Expressionen von τGFP in GnRHR-exprimierenden Zellen erlaubt. GnRHR Neuronen sind weit verbreitet in Bereichen des Gehirns der männlichen Maus, die an geschlechtsspezifischem Verhalten beteilgt sind, einschließlich des PAG. Darüber hinaus konnte GnRH eine Erhöhung des intrazellularen Kalzium induzieren und die Frequenz der Aktionspotentiale in GnRHR-Neuronen modulieren. Die Rolle von GnRHR-Neuronen im Verhalten blieb jedoch unerforscht. Durch die Verwendung des gleichen binären gentischen Ansatzes, hatte ich zunächst das Ziel, das GnRHR Netzwerk in dem PAG des weiblichen Gehirns der Maus bei gleichaltrigen Gruppen zu beschreiben. Ich fand eine breite Verteilung der GnRHR Neuronen spezifisch in der dorsalen und den seitlichen Teilen des PAG, jedoch nicht in dem ventrolateralen PAG. Darüber hinaus nimmt die Anzahl der GnRH Neuronen mit dem Alter zu, was auf eine späte Errichtung des GnRHR-Netzes in das PAG hindeutet. Des weiteren versuchte ich die genetische Ablation von GnRHR Neuronen im dorsalen PAG. Um dies zu tun, injizierte ich ein Adeno-assoziierten Virus im PAG, der die cre-abhängige Expression einer konstitutiv aktiven Form von Caspase-3 vermittelt. Auf diese Weise konnte ich den programmierten Zelltod in den PAG-GnRHR-Neuronen induzieren. Überraschenderweiße beeinflusste die Ablation die weibliche sexuelle Empfänglichkeit nicht. Darüber hinaus habe ich die Aktivität der GnRH Neurone in Bezug auf das weibliche Sexualverhalten mit dem Marker c-fos untersucht. Ich fand eine stark hochregulierte c-fos Aktivität im PAG, jedoch nicht in GnRHR Neuronen. V In einer parallelen Studie untersuchte ich die Rolle des metabotropen Rezeptors 5 (mGluR5) beim Einstzen der Pubertät. Die neuroendokrinen Mechanismen, die den Beginn der Pubertät regulieren, werden weitgehend erforscht, sind aber immer noch unzureichend verstanden. Beweis dafür zeigte die Rolle von Glutamat bei der Regulation von GnRH-Neuronen. Weibliche Mäuse, denen das metabotrope Rezeptor 5 (mGluR5) Gen fehlte, zeigten einen verzögerte Pubertät und eine verminderte Fertilität. Zur Analyse der Gonadotropinfunktion in Abwesenheit von mGluR5 analysierte ich die Serumprofile der gesamten Hypophysenhormone. Ich fand reduzierte Mengen von Follikel-stimulierenden Hormones, jedoch blieb die Menge von luteinisierenden Hormones gleich. Beim Hormonspiegel von Schilddrüsenstimulierenden Hormones bei weiblichen Mäusen, denen das mGluR5-Gen fehlte, konnte ich jedoch einen Anstieg feststellen. Diese Ergebnisse könnten neue Einsichten in die Mechanismen liefern, die die Fruchtbarkeit regulieren und helfen kann dazu beitragen, neue Therapien für Pubertätsstörungen zu entwickeln

Condensati di Bose-Einstein

A dissertation on the fundamental theoretical principles and phenomenological nature of the Bose-Einstein condensation. The thesis, structured in three chapters, shows a model to describe the behavior and the features of an ideal Bose gas in the regime of ultra-low temperatures, and gives an overview of the main experimental techniques used to obtain the condensate. In the first chapter, some fundamental concepts of statistical thermodynamics are introduced to deduce the Bose-Einstein and the Fermi-Dirac distribution functions. The second chapter presents a theoretical model whereby the properties of a bosonic system harmonically trapped are analyzed, followed by a treatise of a few atomic cooling and atomic trapping techniques; particularly laser cooling, evaporative cooling and magneto-optical trapping. The concluding chapter focuses on some remarkable experimental observations, as the first realization of the condensate in rubidium atoms and other application prospects

Comparison of Theory and Direct Numerical Simulations of Drag Reduction by Rodlike Polymers in Turbulent Channel Flows

Numerical simulations of turbulent channel flows, with or without additives, are limited in the extent of the Reynolds number \Re and Deborah number \De. The comparison of such simulations to theories of drag reduction, which are usually derived for asymptotically high \Re and \De, calls for some care. In this paper we present a study of drag reduction by rodlike polymers in a turbulent channel flow using direct numerical simulation and illustrate how these numerical results should be related to the recently developed theory

Cloud for eGov: the state of the art

Specifically, the paper provides a detailed analysis of the state of the art regarding technological, regulatory and interoperability aspects, devoting particular attention to those projects (and related experience) in the field of cloud and distributed computing. The paper's aim is to evaluate benefits and risks of the applicability of solutions that are already in place for the specified areas of interest. The key factors that determine relevant regulations, with particular emphasis on the European target, have been listed in the paper. Finally, the main Italian projects and the situation in some European countries have also been mentioned

Perspects in astrophysical databases

Astrophysics has become a domain extremely rich of scientific data. Data mining tools are needed for information extraction from such large datasets. This asks for an approach to data management emphasizing the efficiency and simplicity of data access; efficiency is obtained using multidimensional access methods and simplicity is achieved by properly handling metadata. Moreover, clustering and classification techniques on large datasets pose additional requirements in terms of computation and memory scalability and interpretability of results. In this study we review some possible solutions

Turbulent Rayleigh-Bénard convection with polymers: Understanding how heat flux is modified

We study how polymers affect the heat flux in turbulent Rayleigh-Bénard convection at moderate Rayleigh numbers using direct numerical simulations with polymers of different relaxation times. We find that heat flux is enhanced by polymers and the amount of heat enhancement first increases and then decreases with the Weissenberg number, which is the ratio of the polymer relaxation time to the typical time scale of the flow. We show that this nonmonotonic behavior of the heat flux enhancement is the combined effect of the decrease in the viscous energy dissipation rate due to the viscosity of the Newtonian fluid and the increase in the energy dissipation rate due to polymers when Weissenberg number is increased. We explain why the viscous energy dissipation rate decreases with the Weissenberg number. Then by carrying out a generalized boundary layer analysis supplemented by a space-dependent effective viscosity from the numerical simulations, we provide a theoretical understanding of the change of the heat flux when the viscous energy dissipation rate is held constant. Our analysis thus provides a physical way to understand the numerical results

Shell Model for Drag Reduction with Polymer Additive in Homogeneous Turbulence

Recent direct numerical simulations of the FENE-P model of non-Newtonian hydrodynamics revealed that the phenomenon of drag reduction by polymer additives exists (albeit in reduced form) also in homogeneous turbulence. We introduce here a simple shell model for homogeneous viscoelastic flows that recaptures the essential observations of the full simulations. The simplicity of the shell model allows us to offer a transparent explanation of the main observations. It is shown that the mechanism for drag reduction operates mainly on the large scales. Understanding the mechanism allows us to predict how the amount of drag reduction depends of the various parameters in the model. The main conclusion is that drag reduction is not a universal phenomenon, it peaks in a window of parameters like Reynolds number and the relaxation rate of the polymer