The ACS LCID Project: Variable Stars in Tucana and LGS3

We present preliminary results concerning the search for short-period variable stars in Tucana and LGS3 based on very deep HST/ACS imaging. In the one chip per galaxy we studied so far, a total of 230 and 80 candidates variables were found, respectively. For Tucana, we identified 134 of them as RR Lyrae stars (RRL) pulsating in the fundamental mode (RRab), 51 in the first-overtone mode (RRc), and 37 in both modes simultaneoulsy (RRd), as well as four candidate anomalous Cepheids (AC). In the case of LGS3, we found 45 RRab and 5 RRc, plus three candidates RRd and five candidate AC. The metallicities obtained from the mean period of the RRab are [Fe/H]_{Tuc}=-1.7 and [Fe/H]_{LGS3}=-1.8.Comment: 2 pages, 1 figure. To appear in the Proceedings of IAU Symposium 241: "Stellar Populations as Building Blocks of Galaxies", 10-16 December, 2006 at La Palma, Canary Islands, Spai

Coherent perfect absorption in photonic structures

The ability to drive a system with an external input is a fundamental aspect of light-matter interaction. The coherent perfect absorption (CPA) phenomenon extends to the general multibeam interference phenomenology the well known critical coupling concepts. This interferometric control of absorption can be employed to reach full delivery of optical energy to nanoscale systems such as plasmonic nanoparticles, and multi-port interference can be used to enhance the absorption of a nanoscale device when it is embedded in a strongly scattering system, with potential applications to nanoscale sensing. Here we review the two-port CPA in reference to photonic structures which can resonantly couple to the external fields. A revised two-port theory of CPA is illustrated, which relies on the Scattering Matrix formalism and is valid for all linear two-port systems with reciprocity. Through a semiclassical approach, treating two-port critical coupling conditions in a non-perturbative regime, it is demonstrated that the strong coupling regime and the critical coupling condition can indeed coexist; in this situation, termed strong critical coupling, all the incoming energy is converted into polaritons. Experimental results are presented, which clearly display the elliptical trace of absorption as function of input unbalance in a thin metallo-dielectric metamaterial, and verify polaritonic CPA in an intersubband-polariton photonic-crystal membrane resonator. Concluding remarks discuss the future perspectives of CPA with photonic structures.Comment: arXiv admin note: substantial text overlap with arXiv:1605.0890

The Araucaria Project. Bright Variable Stars in NGC 6822 from a Wide-Field Imaging Survey

We have performed a search for variable stars in the dwarf irregular galaxy NGC 6822 using wide-field multi-epoch VI photometry down to a limiting magnitude $V$ $\sim$ 22. Apart from the Cepheid variables in this galaxy already reported in an earlier paper by Pietrzynski et al. (2004), we have found 1019 "non-periodic" variable stars, 50 periodically variable stars with periods ranging from 0.12 to 66 days and 146 probably periodic variables. Twelve of these stars are eclipsing binaries and fifteen are likely new, low-amplitude Cepheids. Interestingly, seven of these Cepheid candidates have periods longer than 100 days, have very low amplitudes (less than 0.2 mag in $I$), and are very red. They could be young, massive Cepheids still embedded in dusty envelopes. The other objects span a huge range in colours and represent a mixture of different types of luminous variables. Many of the variables classified as non-periodic in the present study may turn out to be {\it periodic} variables once a much longer time baseline will be available to study them. We provide the catalogue of photometric parameters and show the atlas of light curves for the new variable stars. Our present catalogue is complementary to the one of Baldacci et al. (2005) which has focussed on very short-period and fainter variables in a subfield in NGC 6822.Comment: Accepted for publication in A&

Diagnosi e stadiazione preoperatoria del carcinoma endometriale:la nostra esperienza

Il carcinoma endometriale è la principale causa di morbidità e mortalità per la popolazione femminile, con circa 200 000 casi diagnosticati ogni anno. L' iter diagnostico nella patologia maligna endometriale dovrebbe portare non solo alla diagnosi ma ad una stadiazione preoperatoria quanto più possibile precisa per poter modulare l'approccio chirurgico e/o terapeutico. Il nostro è uno studio retrospettivo di 74 casi di pazienti sottoposte ad intervento chirurgico presso la nostra struttura per adenocarcinoma endometriale o iperplasia atipica dell'endometrio, in seguito a diagnosi istologica ottenuta da biopsia endometriale o revisione della cavità uterina. Scopo dello studio è la valutazione dell'affidabilità della nostra stadiazione preoperatoria delle pazienti, ottenuta mediante esami clinico-strumentali e di imaging (ecografia trans-vaginale, risonanza magnetica, tomografia computerizzata) da cui derivano in parte le strategie terapeutiche. I risultati di queste indagini sono state messe a confronto con i risultati dei referti istologici postoperatori. La biopsia preoperatoria si è dimostrata in grado di rilevare la patologia tumorale nel 68% dei casi, con un errore di diagnosi nel 31.4% dei casi. L'ecografia transvaginale e la risonanza magnetica hanno dimostrato una buona accuratezza diagnostica nel definire l'invasione miometriale del carcinoma endometriale, con una sensibilità lievemente maggiore per la RM rispetto alla TVS, che viceversa mostrava una specificità superiore. La TC ha mostrato una buona specificità nel definire lo stato linfonodale. Anche se la stadiazione definitiva della malattia viene stabilita in base all'istologia postoperatoria, un'accurata stadiazione preoperatoria permette di effettuare un corretto approccio chirurgico per ogni paziente ed evitare la morbidità associata a trattamenti non necessari

Dioniso a Milano: le atopie di Milo De Angelis

The essay focuses on Milo De Angelis’s poetic work, underlying his representation of the city of Milan as a tragic and mythic place, crossed by threatening energies on the basis of which the author emphasizes his dramatic tension with reality.The essay focuses on Milo De Angelis’s poetic work, underlying his representation of the city of Milan as a tragic and mythic place, crossed by threatening energies on the basis of which the author emphasizes his dramatic tension with reality