785 research outputs found
Localization of resonance eigenfunctions on quantum repellers
We introduce a new phase space representation for open quantum systems. This
is a very powerful tool to help advance in the study of the morphology of their
eigenstates. We apply it to two different versions of a paradigmatic model, the
baker map. This allows to show that the long-lived resonances are strongly
scarred along the shortest periodic orbits that belong to the classical
repeller. Moreover, the shape of the short-lived eigenstates is also analyzed.
Finally, we apply an antiunitary symmetry measure to the resonances that
permits to quantify their localization on the repeller.Comment: 4 pages, 4 figure
Behavior of the current in the asymmetric quantum multibaker map
Recently, a new mechanism leading to purely quantum directed transport in the
asymmetric multibaker map has been presented. Here, we show a comprehensive
characterization of the finite asymptotic current behavior with respect to the
value, the shape of the initial conditions, and the features of the
spectrum. We have considered different degrees of asymmetry in these studies
and we have also analyzed the classical and quantum phase space distributions
for short times in order to understand the mechanisms behind the generation of
the directed current.Comment: 8 pages, 8 figure
Peri-implant diseases and metabolic syndrome components: a systematic review
OBJECTIVE:
Metabolic syndrome (MetS) is defined as a spectrum of conditions associated with an increased risk of developing CVD and type 2 diabetes. MetS include: hyperglycemia, hypertension, visceral obesity, dyslipidemia with elevated values of triglycerides (TG) and low levels of HDL. The aim of this review is to provide current knowledge of the relationship between MetS, its components and peri-implant diseases.
MATERIALS AND METHODS:
An electronic literature search was conducted in the English language in several databases. The Newcastle-Ottawa Scale was used for quality assessment of cohort and cross-sectional studies; while systematic reviews were evaluated through AMSTAR; results were reported according to the PRISMA Statement.
RESULTS:
A total of 272 records were identified through database searching, six studies were included for qualitative analysis. No study directly related to MetS was found, there was inconsistent and controversial evidence regarding association with cardiovascular disease. A higher risk of peri-implantitis was detected in people with hyperglycemia.
CONCLUSIONS:
Future research should be orientated in assessing the risk of peri-implant diseases, evaluating patient's therapeutic response, analyzing directionality of the relationship between MetS, its components and biologic implant complications.
Few studies have investigated the possible relationship between systemic conditions and peri-implant diseases. The aim of this review is to present, in a systematic manner, current evidence and knowledge regarding possible association between cardiovascular disease and implant biologic complications. Out of the one-hundred-eighty-nine studies screened, just five studies were selected for qualitative analysis: three cohort studies (one prospective and two retrospectives) and two cross-sectional studies. According to their results, there is inconsistent and controversial evidence regarding association of cardiovascular disease and implant biologic complications. Future research should be orientated in conducting longitudinal studies, evaluating patients affected by cardiovascular disease rehabilitated with dental implants
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Shocks and PDRs in an intermediate mass star forming globule: the case of IC1396N
The dark globule IC1396N is a typical example of a star formation process induced by radiation driven implosion due to the strong UV field from a nearby O6 star. The IRAS source embedded in the globule and its associated molecular outflow have been observed with the Long Wavelength Spectrometer (LWS) on ISO revealing an extremely rich spectrum including: CO rotational lines from J=14-13 up to J=28-27, rotational lines from ortho-H2O, OH lines involving the first four rotational levels of both ladders, atomic (OI 63μm, OI 145μm) and ionic (CII 157μm, OIII 52μm, OIII 88μm) lines. A complex picture arises, where an externally illuminated PDR coexists with strong C-shocks within IC1396N and whose origin is not clear
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High-J CO line emission from young stellar objects: from ISO to FIRST
we present the CO pure rotational spectrum at high J (Jup14) obtained with the Long Wavelength Spectrometer (LWS) on board of the ISO satellite towards molecular outflows exciting sources in nearby star formation regions. The physical conditions, derived using an LVG model for the line emission, indicate the presence of warm and dense gas, probably shock excited. The model fits show that often the bulk of this CO emission is expected in the spectral range that will be covered by FIRST, indicating the potentiality of this satellite to trace the warm component of gas emission in young stellar objects
Progettazione ed installazione di tre telecamere di sorveglianza per il monitoraggio dell’attività dell’Etna nel periodo Luglio-Agosto 2001
La sorveglianza visiva dei vulcani attivi siciliani è una delle attività dell’unità funzionale monitoraggio dell’INGV di Catania e consiste nel monitoraggio video continuo di detti vulcani mediante stazioni permanenti. A seguito dell’attività dell’Etna del Luglio-Agosto 2001, la stazione video che riprendeva i crateri sommitali del vulcano, posta in località La Montagnola, è stata completamente distrutta dall'attività esplosiva ed eruttiva della nuova bocca venutasi a creare a quota 2550 m. s.l.m. a ridosso del fianco settentrionale de La Montagnola. In questo lavoro è stata rappresentata l’opera di progettazione, realizzazione ed installazione di tre stazioni video, una prossimale e due periferiche, per consentire una visione completa e continua di detta attività eruttiva.
La prima telecamera è stata installata al Centro Operativo Acquisizione Dati (CUAD) di Catania, la seconda in località Rifugio Sapienza sul tetto dell’Hotel Corsaro e la terza è stata posizionata al Comune di Milo nell'edificio comunale
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ISO-LWS grating spectroscopy: the case of R CrA star forming region
We present the far infrared spectra of the R CrA star forming region obtained with ISO-LWS. We collected a pointed observation on the Herbig Ae star R CrA and a raster scan covering the surrounding region, where HH100 (with its exciting source) and the pre-Main Sequence star T CrA are located. The OI 63μm and the CII 158μm lines have been detected in all the pointed positions, with a ratio consistent with PDR excitation. CO rotational lines (between Jup=14 and Jup=19) are detected on R CrA; from their intensities we derived, using a LVG model, the density and temperature of the emitting region. Other molecular transitions (OH and H2O) have been detected on the investigated objects; the derived cooling of all the molecular species is in agreement with C-shock as the likely excitation mechanism. The continuum emission of R CrA peaks around 100μm (as expected for a Herbig star) while the other sources (T CrA, HH100) show increasing continua up to ~200μm, indicating that they are probably less evolved sources
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