Irreducible decompositions and stationary states of quantum channels

For a quantum channel (completely positive, trace-preserving map), we prove a generalization to the infinite dimensional case of a result by Baumgartner and Narnhofer. This result is, in a probabilistic language, a decomposition of a general quantum channel into its irreducible positive recurrent components. This decomposition is related with a communication relation on the reference Hilbert space. This allows us to describe the full structure of invariant states of a quantum channel, and of their supports

On a generalized Central Limit Theorem and Large Deviations for Homogeneous Open Quantum Walks

We consider homogeneous open quantum random walks on a lattice with finite dimensional local Hilbert space and we study in particular the position process of the quantum trajectories of the walk. We prove that the properly rescaled position process asymptotically approaches a mixture of Gaussian measures. We can generalize the existing central limit type results and give more explicit expressions for the involved asymptotic quantities, dropping any additional condition on the walk. We use deformation and spectral techniques, together with reducibility properties of the local channel associated with the open quantum walk. Further, we can provide a large deviations' principle in the case of a fast recurrent local channel and at least lower and upper bounds in the general case.Comment: 31 pages, 9 figure

Large Deviations, Central Limit and dynamical phase transitions in the atom maser

The theory of quantum jump trajectories provides a new framework for understanding dynamical phase transitions in open systems. A candidate for such transitions is the atom maser, which for certain parameters exhibits strong intermittency in the atom detection counts, and has a bistable stationary state. Although previous numerical results suggested that the "free energy" may not be a smooth function, we show that the atom detection counts satisfy a large deviations principle, and therefore we deal with a phase cross-over rather than a genuine phase transition. We argue however that the latter occurs in the limit of infinite pumping rate. As a corollary, we obtain the Central Limit Theorem for the counting process. The proof relies on the analysis of a certain deformed generator whose spectral bound is the limiting cumulant generating function. The latter is shown to be smooth, so that a large deviations principle holds by the Gartner-Ellis Theorem. One of the main ingredients is the Krein-Rutman Theorem which extends the Perron-Frobenius theory to a general class of positive compact semigroups.Comment: 29 pages, 18 figures; added central limit theorem, clarified proof of main result, added new figures and reference

Interleukin-18 mediates cardiac dysfunction induced by western diet independent of obesity and hyperglycemia in the mouse

Obesity and diabetes are independent risk factors for heart failure and are associated with the consumption of diet rich in saturated fat and sugar, Western diet (WD), known to induce cardiac dysfunction in the mouse through incompletely characterized inflammatory mechanisms. We hypothesized that the detrimental cardiac effects of WD are mediated by interleukin-18 (IL-18), pro-inflammatory cytokine linked to cardiac dysfunction. C57BL/6J wild-type male mice and IL-18 knockout male mice were fed high-saturated fat and high-sugar diet for 8 weeks. We measured food intake, body weight and fasting glycemia. We assessed left ventricular (LV) systolic and diastolic function by Doppler echocardiography and cardiac catheterization. In wild-type mice, WD induced a significant increase in isovolumetric relaxation time, myocardial performance index and left ventricular end-diastolic pressure, reflecting an impairment in diastolic function, paired with a mild reduction in LV ejection fraction. IL-18 KO mice had higher food intake and greater increase in body weight without significant differences in hyperglycemia. Despite displaying greater obesity, IL-18 knockout mice fed with WD for 8 weeks had preserved cardiac diastolic function and higher left ventricular ejection fraction. IL-18 mediates diet-induced cardiac dysfunction, independent of food intake and obesity, thus highlighting a disconnect between the metabolic and cardiac effects of IL-18

Le cure palliative nel malato internistico: focus sulle malattie croniche in fase avanzata

Prefazione - Il ruolo del palliativista in medicina interna Gino Gobber Il ruolo del medico internista nelle cure palliative Dario Manfellotto Le cure palliative nel malato non-oncologico Italo Penco La cura del malato fragile alla fine della vita Andrea Fontanella La scuola di specializzazione in Medicina e Cure Palliative Gino Gobber; Dario Manfellotto Introduzione Fabio Gilioli Strumenti per identificare la complessità dei bisogni clinici-assistenziali dei malati e delle loro famiglie Filippo Canzani; Claudio Santini Gestione dei sintomi in fase avanzata: dispnea, delirium, rantolo, nausea e vomito, occlusione intestinale Matteo Moroni Gestione dei sintomi in fase avanzata e nel fine vita: dolore Giuseppe Civardi Approccio assistenziale ai sintomi in fase avanzata e nel fine vita Gabriella Bordin; Michela Guarda De-prescrizione, rimodulazione e sospensione diagnostiche e terapeutiche in fase avanzata di malattia Carlo Lorenzo Muzzulini; Michele Berardi; Alessandro Valle Antibioticoterapia nelle cure palliative Matteo Moroni; Filippo Costanzo Emotrasfusioni in cure palliative Filomena Panzone; Raffaella Antonione Terapia anticoagulante in cure palliative Mauro Silingardi; Raffaella Antonione Ventilazione non invasiva in cure palliative Federico Lari; Raffaella Antonione Scelte terapeutiche in medicina interna: come non perdersi nella complessità del fine vita Miriam Cappelli; Mauro Carbone Raccomandazioni conclusiv

Bioengineering, augmented reality, and robotic surgery in vascular surgery: A literature review

Biomedical engineering integrates a variety of applied sciences with life sciences to improve human health and reduce the invasiveness of surgical procedures. Technological advances, achieved through biomedical engineering, have contributed to significant improvements in the field of vascular and endovascular surgery. This paper aims to review the most cutting-edge technologies of the last decade involving the use of augmented reality devices and robotic systems in vascular surgery, highlighting benefits and limitations. Accordingly, two distinct literature surveys were conducted through the PubMed database: the first review provides a comprehensive assessment of augmented reality technologies, including the different techniques available for the visualization of virtual content (11 papers revised); the second review collects studies with bioengineering content that highlight the research trend in robotic vascular surgery, excluding works focused only on the clinical use of commercially available robotic systems (15 papers revised). Technological flow is constant and further advances in imaging techniques and hardware components will inevitably bring new tools for a clinical translation of innovative therapeutic strategies in vascular surgery

Wavelet Analysis as a Tool to Localize Magnetic and Cross-helicity Events in the Solar Wind

In this paper, we adopt the use of the wavelet transform as a new tool to investigate the time behavior at different scales of reduced magnetic helicity, cross-helicity, and residual energy in space plasmas. The main goal is a better characterization of the fluctuations in which interplanetary flux ropes are embedded. This kind of information is still missing in the present literature, and our tool can represent the basis for a new treatment of in situ measurements of this kind of event. There is a debate about the origins of small-scale flux ropes. It has been suggested that they are formed through magnetic reconnection in the solar wind, such as across the heliospheric current sheet. On the other hand, it has also been suggested that they are formed in the corona, similar to magnetic clouds. Thus, it looks like that there are two populations, one originating in the solar wind via magnetic reconnection across the current sheet in the inner heliosphere and the other originating in the corona. Small-scale flux ropes might be the remnants of the streamer belt blobs formed from disconnection; however, a one-to-one observation of a blob and a small-scale flux rope in the solar wind has yet to be found. Within this panorama of possibilities, this new technique appears to be very promising in investigating the origins of these objects advected by the solar wind

Large Deviations, Central Limit and dynamical phase transitions in the atom maser

The theory of quantum jump trajectories provides a new framework for understanding dynamical phase transitions in open systems. A candidate for such transitions is the atom maser, which for certain parameters exhibits strong intermittency in the atom detection counts, and has a bistable stationary state. Although previous numerical results suggested that the "free energy" may not be a smooth function, we show that the atom detection counts satisfy a large deviations principle, and therefore we deal with a phase cross-over rather than a genuine phase transition. We argue however that the latter occurs in the limit of infinite pumping rate. As a corollary, we obtain the Central Limit Theorem for the counting process. The proof relies on the analysis of a certain deformed generator whose spectral bound is the limiting cumulant generating function. The latter is shown to be smooth, so that a large deviations principle holds by the Gärtner-Ellis Theorem. One of the main ingredients is the Krein-Rutman theory which extends the Perron-Frobenius theorem to a general class of positive compact semigroups