Synthetic Stellar Clusters for Pop III

We present preliminary results of an incoming theoretical work concerning the integrated properties of the Population III clusters of stars. On the basis of synthetic Color-Magnitude Diagrams, we provide a grid of optical and near-IR colors of Simple Stellar Populations with very low metallicity (Z=10$^{-10}$ and Z=10$^{-6}$) and age which spans from 10 Myr to 15 Gyr. A comparison with higher metallicities up to 0.006 is also shown, disclosing sizable differences in the CMD morphology, integrated colors and Spectral Energy Distribution (SED).Comment: 2 pages, incl. 2 figures, "The First Stars", Proceedings of the second MPA/ESO workshop, Eds.: Weiss, Abel, Hill, Springer, Heidelberg, 200

CRIL. Under the light of the sun also the sounds shine: Photography, a mode of inhabiting the world

This project has its origin in an article for the first number of the magazine Passagens and it was redone(1) for my Master Thesis, presented at the Faculty of Architecture of Palermo in 2013. One intends here to question photography as a way to inhabit the world, where the watching of photography is a keeping and a taking care of. Photography here is understood as a vehicle of the images of the world and in a certain sense as a construction of a real, as other representations can do it, but with the peculiarity of being, among other signs, content in the semiotic theory of Peirce. This content, as among others refer Roland Barthes(2) and Rosalind Krauss(3), is demonstration of the veracity of the photographic images whose origin was in a “reality”. The connection between the chosen reality and my watching coincides on the photographic surface, that is: the reference transfers to the watching of the author or the spectator. To inhabit is like a question which that reference puts in a condition of otherness, welcomes, attempting at an answer. The spaces, the objects of these photographs, are found along the CRIL (the internal ring road of Lisbon), which, together with the river Tagus, form a circle around the city. This is an urban path that connects in a little time the architectures and the urbanisations I photographed, through roundabouts, exits exclusively for all kinds of motor vehicles: private, public and heavy transports. The automobile is in fact the only way to be, temporarily and in a relative movement, in that urban space. To watch this route inside the compartment is like being seated in an armchair watching a road movie, of which we can decide even the speed of the frames, the beginning and the end of the sequences, as well as the soundtrack. But never stop or leave the "sequence plan" other than by the exits especially designed for that effect. I covered each exit and roundabout of those 20 km, whether in fractions or in its total extension. The construction of the cabin, the unlimited possibilities to stop, the linearity of the perspectives through which to look, induced in me the need to leave that ring road. Every driver wishes to reduce to the minimum that waiting time, and does not see much of that sequence plan, composed mostly of road signs, shopping centres and billboards, exactly like a film on TV constantly interleaved by advertising blocks. The relation that each of us has with a space, like the speed with which we watch it, determines the outcome of that observation and the meaning we give it. To produce photographs implies a time that needs to be found and cut off the mechanical routine of life, and one needs mostly to be aware of oneself and everything that surrounds us. To photograph from the automobile would have been like changing the direct experience in the space that I ascribe to the photographic act, as a reflex of an observed reality, eradicating that essential part of its process which is to find the place itself in which one is able to be.info:eu-repo/semantics/publishedVersio

On the observational properties of He-burning stars: some clues on the tilt of the HB in metal rich clusters

We investigate the predicted Color-Magnitude distribution of metal-rich Horizontal Branch (HB) stars, discussing selected theoretical models computed under various assumptions about the star metallicity and the efficiency of super-adiabatic convection. We find that canonical Zero Age Horizontal Branches with metallicity larger or of the order of Z=0.002 should be all affected by a tilt, by an amount which increases when the metallicity is increased and/or the mixing length is decreased, reaching a tilt of $\Delta V \sim$0.2 mag in the case of solar metallicity when a mixing length value $\alpha$=1.6 is assumed ($\Delta V$ is the magnitude difference between the top of the blue HB and the fainter magnitude reached by the red HB). Uncertainties in the luminosity of the red HB due to uncertainty in the mixing length value are discussed. We finally discuss the much larger tilt observed in the clusters NGC 6441 and NGC 6388, reporting additional evidence against suggested non-canonical evolutionary scenarios. Numerical experiments show that differential reddening could produce such sloped HBs. Further, HST-PC imaging of NGC 6441 gives clear indications about the occurrence of differential reddening across the cluster. However, the same imaging shows that the observed slope of the red HB {\em is not} an artifact of differential reddening. We finally show that sloping red HBs in metal rich clusters are a common occurrence not necessarily correlated with the appearance of extended blue HB.Comment: 14 pages, 9 figures, Accepted by Ap

On formalising and analysing the tweetchain protocol

Distributed Ledger Technology is demonstrating its capability to provide flexible frameworks for information assurance capable of resisting to byzantine failures and multiple target attacks. The availability of development frameworks allows the definition of many applications using such a technology. On the contrary, the verification of such applications are far from being easy since testing is not enough to guarantee the absence of security problems. The paper describes an experience in the modelling and security analysis of one of these applications by means of formal methods: in particular, we consider the Tweetchain protocol as a case study and we use the Tamarin Prover tool, which supports the modelling of a protocol as a multiset rewriting system and its analysis with respect to temporal first-order properties. With the aim of making the modeling and verification process reproducible and independent of the specific protocol, we present a general structure of the Tamarin Prover model and of the properties to verified. Finally, we discuss the strengths and limitations of the Tamarin Prover approach considering three aspects: modelling, analysis and the verification process. Copyrigh

Geometric phase and gauge theory structure in quantum computing

We discuss the presence of a geometrical phase in the evolution of a qubit state and its gauge structure. The time evolution operator is found to be the free energy operator, rather than the Hamiltonian operator.Comment: 5 pages, presented at Fifth International Workshop DICE2010: Space-Time-Matter - current issues in quantum mechanics and beyond, Castiglioncello (Tuscany), September 13-17, 201

Extracellular vesicle microRNAs contribute to the osteogenic inhibition of mesenchymal stem cells in multiple myeloma

Osteolytic bone disease is the major complication associated with the progression of multiple myeloma (MM). Recently, extracellular vesicles (EVs) have emerged as mediators of MM-associated bone disease by inhibiting the osteogenic differentiation of human mesenchymal stem cells (hMSCs). Here, we investigated a correlation between the EV-mediated osteogenic inhibition and MM vesicle content, focusing on miRNAs. By the use of a MicroRNA Card, we identified a pool of miRNAs, highly expressed in EVs, from MM cell line (MM1.S EVs), expression of which was confirmed in EVs from bone marrow (BM) plasma of patients affected by smoldering myeloma (SMM) and MM. Notably,we found that miR-129-5p, which targets different osteoblast (OBs) differentiation markers, is enriched in MM-EVs compared to SMM-EVs, thus suggesting a selective packaging correlated with pathological grade. We found that miR-129-5p can be transported to hMSCs by MM-EVs and, by the use of miRNA mimics, we investigated its role in recipient cells. Our data demonstrated that the increase of miR-129-5p levels in hMSCs under osteoblastic differentiation stimuli inhibited the expression of the transcription factor Sp1, previously described as a positive modulator of osteoblastic differentiation, and of its target the Alkaline phosphatase (ALPL), thus identifying miR-129-5p among the players of vesicle-mediated bone disease