Synthetic extinction maps around intermediate-mass black holes in Galactic globular clusters

During the last decades, much effort has been devoted to explain the discrepancy between the amount of intracluster medium (ICM) estimated from stellar evolution theories and that emerging from observations in globular clusters (GCs). One possible scenario is the accretion of this medium by an intermediate-mass black hole (IMBH) at the centre of the cluster. In this work, we aim at modelling the cluster colour-excess profile as a tracer of the ICM density, both with and without an IMBH. Comparing the profiles with observations allows us to test the existence of IMBHs and their possible role in the cleansing of the ICM. We derive the intracluster density profiles from hydrodynamical models of accretion onto a central IMBH in a GC and we determine the corresponding dust density. This model is applied to a list of 25 Galactic GCs. We find that central IMBHs decrease the ICM by several orders of magnitude. In a subset of 9 clusters, the absence of the black hole combined with a low intracluster medium temperature would be at odds with present gas mass content estimations. As a result, we conclude that IMBHs are an effective cleansing mechanism of the ICM of GCs. We construct synthetic extinction maps for M 62 and {\omega} Cen, two clusters in the small subset of 9 with observed 2D extinction maps. We find that under reasonable assumptions regarding the model parameters, if the gas temperature in M 62 is close to 8000 K, an IMBH needs to be invoked. Further ICM observations regarding both the gas and dust in GCs could help to settle this issue.Comment: Accepted for publication in MNRAS.11 pages, 7 figure

MIDAS: Automated Approach to Design Microwave Integrated Inductors and Transformers on Silicon

The design of modern radiofrequency integrated circuits on silicon operating at microwave and millimeter-waves requires the integration of several spiral inductors and transformers that are not commonly available in the process design-kits of the technologies. In this work we present an auxiliary CAD tool for Microwave Inductor (and transformer) Design Automation on Silicon (MIDAS) that exploits commercial simulators and allows the implementation of an automatic design flow, including three-dimensional layout editing and electromagnetic simulations. In detail, MIDAS allows the designer to derive a preliminary sizing of the inductor (transformer) on the bases of the design entries (specifications). It draws the inductor (transformer) layers for the specific process design kit, including vias and underpasses, with or without patterned ground shield, and launches the electromagnetic simulations, achieving effective design automation with respect to the traditional design flow for RFICs. With the present software suite the complete design time is reduced significantly (typically 1 hour on a PC based on Intel® Pentium® Dual 1.80GHz CPU with 2-GB RAM). Afterwards both the device equivalent circuit and the layout are ready to be imported in the Cadence environment

Feedback local optimality principle applied to rocket vertical landing VTVL

Vertical landing is becoming popular in the last fifteen years, a technology known under the acronym VTVL, Vertical Takeoff and Vertical Landing [1,2]. The interest in such landing technology is dictated by possible cost reductions [3,4], that impose spaceship’s recycling. The rockets are not generally de- signed to perform landing operations, rather their design is aimed at takeoff operations, guaranteeing a very high forward acceleration to gain the velocity needed to escape the gravitational force. In this paper a new control method based on Feedback Local Optimality Principle, named FLOP is applied to the rocket landing problem. The FLOP belongs to a special class of optimal controllers, developed by the mechatronic and vehicle dynamics lab of Sapienza, named Variational Feedback Controllers - VFC, that are part of an ongoing research and are recently applied in different field: nonlinear system [5], marine and terrestrial autonomous vehicles [6,7,8], multi agents interactions and vibration control [9, 10]. The paper is devoted to show the robustness of the nonlinear controlled system, comparing the performances with the LQR, one of the most acknowledged methods in optimal control

Time-resolved carrier dynamics and electron-phonon coupling strength in proximized weak ferromagnet-superconductor nanobilayers

We present our femtosecond optical pump-probe studies of proximized ferromagnet-superconductor nanobilayers. The weak ferromagnetic nature of a thin NiCu film makes it possible to observe the dynamics of the nonequilibrium carriers through the near-surface optical reflectivity change measurements. The subpicosecond biexponential reflectivity decay has been identified as electron-phonon Debye and acoustic phonon relaxation times, and the decay of Debye phonons versus temperature dependence was used to evaluate the electron-phonon coupling constants for both the pure Nb and proximized Nb/NiCu heterostructures down to low temperatures. We have also demonstrated that the NiCu overlay on top of Nb dramatically reduced the slow, bolometric component of the photoresponse component, making such bilayers attractive for future radiation detector applications

Design of a Prototype Model Aircraft Utilizing Propulsive Airfoil Technology

Researchers have considered the concept of a simple, compact aircraft for personal use for many years. To date, no effort has led to the development of a practical and affordable vehicle. The Computational Fluid Dynamics (CFD) Lab atSyracuseUniversity, however, has been researching a distributed propulsion technique, called propulsive airfoil technology, that has significant promise to meet the requirements for personal ownership of a small, hybrid road and air vehicle. The propulsive airfoil concept is rooted in HVAC technology, utilizing a cross-flow fan (CFF) embedded into the trailing edge of a thick airfoil section, drawing in air from the top surface of the airfoil. The accelerated flow is ingested into the CFF, and the energized flow is then expelled through an adjustable nozzle at the rear of the airfoil. Research to date has been primarily based on CFD simulations of the two-dimensional cross-section. The simulations have shown that the CFF has two functions. First, the CFF acts as a flow control device, delaying flow separation on the suction surface. This is possible because the fan draws air over the top surface alleviating the adverse pressure gradient. Using nozzles, the outflow can be vectored to provide thrust for the aircraft, which is the second primary function of the propulsive airfoil. This thesis documents the design and implementation of the propulsive airfoil technology into a functional, remotely controlled prototype aircraft. The prototype design project was initiated in conjunction with the development of a wind tunnel experiment to confirm the simulation data and to demonstrate the advantages of utilizing this type of distributed propulsion system. Studying the flight mechanics of this type of aircraft showed that incorporating this technology was feasible, based on the results of CFD simulations. Success in upcoming flight tests of the prototype aircraft will demonstrate the credibility of the concept and support the feasibility of personal ownership of small aircraft using propulsive airfoil technology

Le parole, i dipinti e il mondo in un frammento empedocleo e in un passo platonico

The aim of this work is to carry out a comparison between an Empedocles’ fragment with a Plato’s passage. Empedocles’ passage is fragment B23, which shows a parallel between the creation of painted images and the appearance of entities in the world. Plato’s passage is taken from the Cratylus (424d-425a), in which the author estab- lishes a similarity between the way in which colours, in a portrait, refer to something in reality, and the way in which the grammata, in a word, refer to an entity of reality. These two passages, if compared, show their obvious differences, but also an undeniable con- sonance. This consonance is detectable in reference to the painting meant as a mixture of colours, to the mixture meant as a creation of entities, and to creation meant as a manifestation of words, of images

Domain wall suppression in trapped mixtures of Bose-Einstein condensates

The ground state energy of a binary mixture of Bose-Einstein condensates can be estimated for large atomic samples by making use of suitably regularized Thomas-Fermi density profiles. By exploiting a variational method on the trial densities the energy can be computed by explicitly taking into account the normalization condition. This yields analytical results and provides the basis for further improvement of the approximation. As a case study, we consider a binary mixture of $^{87}$Rb atoms in two different hyperfine states in a double well potential and discuss the energy crossing between density profiles with different numbers of domain walls, as the number of particles and the inter-species interaction vary.Comment: 9 page

Le donne, le parole e le cose. Filosofia, femminilità e finzione nel mondo antico

In this text the authors focus on two female figures of ancient greek litera- ture: Antigone and Helen. The first is the heroine of the Sophocle’s tragedy, the second is the homeric and sophistic figure of woman that is the cause of the Trojan War. In the Sophocle’s famous play, produced in Athens in the fifth century BC, Antigone decides to die to be faithful to the unwritten laws of respect for their dead loved ones against the written laws of the city. In the Gorgia’s text, also produced in the fifth century BC, Helen represents not only the mythical character of the homeric epic, but also the power of the word and the word as a drug. In the last part of this text the authors focus also on the Plato’s Timaeus, where Plato speaks of the chora as a material to be molded, as a mother, as a poet who receives divine inspiration

Weighing up fish and omega-3 PUFA advice with accurate, balanced scales: stringent controls and measures required for clinical trials

[Editorial] Your patients seek sage health and therapeutic advice. However, focussing on strong evidence-based advice is challenging while wading through disparate clinical studies and dispelling the confusing, sometimes apparently contradictory, out-of-context or incorrect messages trafficking to the public via news and internet media, fuelled by the noisy plethora of commercial \u27nutriceutical\u27 and \u27food pharmacy\u27 products. The cardiovascular benefits of dietary omega-3 long chain polyunsaturated fatty acids (LC PUFA) have been of increasing public and health professional attention and interest for the past several decades. It is therefore timely and important that such benefits are reviewed by Nestel et al., in this issue of Heart Lung and Circulation [1]. In this update of the 2008 National Heart Foundation of Australia (NHF) recommendations on clinical evidence for omega-3 PUFA in prevention and treatment of cardiovascular disease, Nestel et al. conclude that whilst there are clear benefits of eating fish, there is no additional support to recommend the use of refined fish oil supplements

Extrasolar planets and brown dwarfs around A-F type stars. II. A planet found with ELODIE around the F6V star HD 33564

We present here the detection of a planet orbiting around the F6V star HD 33564. The radial velocity measurements, obtained with the ELODIE echelle spectrograph at the Haute-Provence Observatory, show a variation with a period of 388 days. Assuming a primary mass of 1.25 Mo, the best Keplerian fit to the data leads to a minimum mass of 9.1 MJup for the companion.Comment: 5 pages. Final version, accepted for publication (A&A). Some Spitzer results on HD33564 (taken this year; not yet published), finally show that the detection of IR excess around this star (by IRAS) is spuriou