Floquet bound states around defects and adatoms in graphene

Recent studies have focused on laser-induced gaps in graphene which have been shown to have a topological origin, thereby hosting robust states at the sample edges. While the focus has remained mainly on these topological chiral edge states, the Floquet bound states around defects lack a detailed study. In this paper we present such a study covering large defects of different shape and also vacancy-like defects and adatoms at the dynamical gap at $\hbar\Omega/2$ ($\hbar\Omega$ being the photon energy). Our results, based on analytical calculations as well as numerics for full tight-binding models, show that the bound states are chiral and appear in a number which grows with the defect size. Furthermore, while the bound states exist regardless the type of the defect's edge termination (zigzag, armchair, mixed), the spectrum is strongly dependent on it. In the case of top adatoms, the bound states quasi-energies depend on the adatoms energy. The appearance of such bound states might open the door to the presence of topological effects on the bulk transport properties of dirty graphene.Comment: 16 pages, 14 figure

Spin interference and Fano effect in electron transport through a mesoscopic ring side-coupled with a quantum dot

We investigate the electron transport through a mesoscopic ring side-coupled with a quantum dot(QD) in the presence of Rashba spin-orbit(SO) interaction. It is shown that both the Fano resonance and the spin interference effects play important roles in the electron transport properties. As the QD level is around the Fermi energy, the total conductance shows typical Fano resonance line shape. By applying an electrical gate voltage to the QD, the total transmission through the system can be strongly modulated. By threading the mesoscopic ring with a magnetic flux, the time-reversal symmetry of the system is broken, and a spin polarized current can be obtained even though the incident current is unpolarized.Comment: 5 pages, 5 figure

A search in the COS-B data base for correlated time variability in regions containing objects of interest

As is well known, association of the gamma-ray sources with celestial objects is, in general, difficult on a pure positional basis, while correlated time variability could obviously provide such proof. This technique can be employed on regions of the gamma-ray sky containing interesting objects of known variability at some wavelength even in the absence of a recognized gamma-ray excess with the aim to extract a weak but predictable signal from the surrounding noise. This technique is applied here on a longer variability time scale, generally of the order of days. Photons coming from the sky regions centered on the various celestial objects considered were selected with energies 100 MeV and with arrival directions within an energy-dependent area of radius of approx 6 deg at 100 MeV. In order to construct a time profile of such photons, their arrival times were grouped in bins of dimensions defined by the available photons number and by the value of the period searched for

IL2 treatment for cancer: from biology to gene therapy.

In this review we shall discuss the biological rationale and the clinical findings obtained using Interleukin 2 (IL2)-based immunotherapy in the management of cancer patients. Objective and long-lived clinical responses have been documented in a proportion of cases, particularly renal cell carcinoma, melanoma and acute myeloid leukaemia. Though encouraging, the clinical use of IL2 has so far been limited by toxicity, as well as by the heterogeneous and unpredictable responses and by the lack of specific anti-tumour effect. These considerations have led to the belief that more sophisticated technologies aimed at introducing the IL2 gene into the neoplastic cells may potentially overcome some of the limitations coupled to the in vivo infusion of high doses of IL2. The data accumulated in animal models and, more recently, also with human tumour cells indicate that the IL2 gene may be successfully inserted into neoplastic cells. The constitutive secretion of IL2 by the tumour cells leads to a reduced or abrogated tumorigenicity in several different tumour models. The evidence that in some experimental tumours the transduction of the IL2 gene into the neoplastic cells may elicit a specific cytotoxic response and confer anti-tumour memory, suggests that vaccination protocols based on this innovative strategy may represent a potential new tool in the management of cancer patients

Floquet interface states in illuminated three-dimensional topological insulators

Recent experiments showed that the surface of a three dimensional topological insulator develops gaps in the Floquet-Bloch band spectrum when illuminated with a circularly polarized laser. These Floquet-Bloch bands are characterized by non-trivial Chern numbers which only depend on the helicity of the polarization of the radiation field. Here we propose a setup consisting of a pair of counter-rotating lasers, and show that one-dimensional chiral states emerge at the interface between the two lasers. These interface states turn out to be spin-polarized and may trigger interesting applications in the field of optoelectronics and spintronics.Comment: 5 pages with 3 figures + supplemental materia

How to develop internal innovation in the media: A case study of best practices for media outlet

The goals intended are to analyze media outlets from the inside, to provide some guidelines on the best practices for media companies that want to shape/reshape their business to survive and grow in the currently troubled media ecosystem. The main questions are to understand how legacy media in Portugal are facing the changing media ecosystem, in special how are they using any kind of internal innovation strategies to outcome the decreasing of sales and/or audiences and advertising revenues. We also pretend to frame this national reality into a broader picture, contextualizing the analysis. So we pose the following questions: are the Portuguese media outlets seeking internal innovation to face and outcome the fall of traditional business models? How legacy media can change from the inside? What processes are they creating/recreating that affect the news production and dissemination? What processes are they creating/recreating that affect the revenue stream? How the Portuguese media ecosystem compares to the international best practices? What guidelines can be identified to help legacy media or journalistic startups to survive in a troubled sea? To achieve the objectives we use non-participatory observation on three Portuguese newsrooms, and interview some of its managers/editorial managers, chosen by its diversity: a TV network that includes, among others, a free-to-air legacy TV channel with the most viewed eight o’clock news program and a 24/7 TV news channel; a national broadcast news radio; an online only newspaper. All three have their online operations, via website and apps. Both the TV and the radio are legacy media that, through different approaches and rhythms, are reshaping their business models, news production processes and news product. Both have internal innovation strategies that we observe, register and analyze. The online newspaper was born has an online only operation, not needing to transform from a legacy/analog operation, but still develops internal innovation strategies to evolve in an always moving digital media landscape. The study cases are built from framed analysis and previous academic work produced by authors like Lucy Kung, Ramón Salaverría, Anderson, Bell & Shirky, Mark Deuze, Bastos & Zamith, Paul Bradshaw, Adelino Gomes, Gureskin, Seave & Graves, Lowe, Gregory & Brown, Storsul, Tanja & Krumsvik, Janine Warner or Barbie Zelizer. So we try to identify the focus on the practices inside the Portuguese case studies, internal innovation strategies on newsrooms, entrepreneurial strategies to change from the traditional business model and boost the financial results. We also try to deliver and promote some guidelines to media outlets that want to innovate and/or to entrepreneurs wanting to create journalistic startups, and to boost the discussion about the need to improve the internal mechanisms of change to survive in a troubled media ecosystem.info:eu-repo/semantics/acceptedVersio

Topological and flat bands states induced by hybridized interactions in one-dimensional photonic lattices

We report on a study of a one-dimensional linear photonic lattice hosting, simultaneously, fundamental and dipolar modes at every site. We show how, thanks to the interaction between the different orbital modes, this minimal model exhibits rich transport and topological properties. By varying the detuning coefficient we find a regime where bands become flatter (with reduced transport) and, a second regime, where both bands connect on at a gap-closing transition (with enhanced transport). We detect an asymmetric transport due to the asymmetric inter-mode coupling and a linear energy exchange mechanism between modes. Further analysis show that the bands have a topological transition with a non-trivial Zak phase which leads to the appeareance of edge states in a finite system. Finally, for zero detuning, we found a symmetric condition for coupling constants, where the linear spectrum becomes completely flat, with states fully localized in space occupying only two lattice sites.Comment: 8 pages, 5 figure

Imaging of biliary involvement in sarcoidosis: Computed tomography, magnetic resonance cholangiopancreatography, and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging findings

Sarcoidosis is a multisystem disease usually affecting the chest, hilar lymph nodes, and lungs, but can potentially involve any organ; therefore, its clinical presentation may vary. Hepato-biliary involvement is rare, and typically asymptomatic; however, it can lead to cirrhosis, and may require liver transplantation. In this report, we present a rare case of a patient affected by sarcoidosis with hepatobiliary involvement. He presented to our hospital complaining of dyspnea triggered by moderate efforts and oppressive thoracic discomfort. Chest X-ray showed multiple bilateral nodular opacities and enlargement of both hilar regions, confirmed by a subsequent total-body computed tomography scan and positron emission tomography, which also revealed cardiac, splenic, and hepatic involvement. Liver function was studied via gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging, and magnetic resonance cholangiopancreatography (MRCP) was also performed. The diagnosis of sarcoidosis was finally achieved via liver biopsy, revealing non-necrotizing granulomas in the periportal space. The patient was treated with prednisone per os, with regression of all lesions at all levels. Although other cases of biliary sarcoidosis have been described, this report provides a complete image set of Gd-EOB-DTPA-enhanced magnetic resonance and MRCP images that is lacking in the English literature, and which may be useful for diagnosis