Scanning tunneling microscopy simulations of poly(3-dodecylthiophene) chains adsorbed on highly oriented pyrolytic graphite

We report on a novel scheme to perform efficient simulations of Scanning Tunneling Microscopy (STM) of molecules weakly bonded to surfaces. Calculations are based on a tight binding (TB) technique including self-consistency for the molecule to predict STM imaging and spectroscopy. To palliate the lack of self-consistency in the tunneling current calculation, we performed first principles density-functional calculations to extract the geometrical and electronic properties of the system. In this way, we can include, in the TB scheme, the effects of structural relaxation upon adsorption on the electronic structure of the molecule. This approach is applied to the study of regioregular poly(3-dodecylthiophene) (P3DDT) polymer chains adsorbed on highly oriented pyrolytic graphite (HOPG). Results of spectroscopic calculations are discussed and compared with recently obtained experimental datComment: 15 pages plus 5 figures in a tar fil

Linguistic prosody and comprehension of idioms and proverbs in subjects of school age

A crucial component of language is represented by the prosodic system because it provides essential elements to speaker about how a sentence should be interpreted or intended (Fodor, 2002). Increasing interest from researchers also relates to the understanding of figurative language (Levorato, & Cacciari, 2002). In the figures of speech that the speaker wants the listener intends something more or different than what is explicitly stated (Glucksberg, 2001).. In particular, prosodic intonation is crucial in the resolution of syntactic ambiguity and structural features that constitute the complex messages, such as idioms and proverbs. A crucial component of language, therefore, is represented by the prosodic system because it provides essential elements to talking about how a sentence should be interpreted or understood . The ability to relate to metalinguistic understanding the cognitive processes that allow you to reflect on language and manipulate its characteristics. These capabilities are essential to recognize and resolve the ambiguities of a complex message, you can control and plan the way we produce and understand language (Levorato, 2007). The study demonstrates that an understanding prosodic correlates with the understanding of idioms and proverbs, which are crucial for the achievement of metalinguistic awareness, are influenced by the level of schooling and socio-cultural

Frontiers of beam diagnostics in plasma accelerators: measuring the ultra-fast and ultra-cold

Advanced diagnostics are essential tools in the development of plasma-based accelerators. The accurate measurement of the quality of beams at the exit of the plasma channel is crucial to optimize the parameters of the plasma accelerator. 6D electron beam diagnostics will be reviewed with emphasis on emittance measurement, which is particularly complex due to large energy spread and divergence of the emerging beams, and on femtosecond bunch length measurements

Mapping the citizen news landscape: blurring boundaries, promises, perils and beyond

Within a short space of time, citizen journalism went from something of a novelty to a naturalized part of the news ecosystem and entered the daily language of journalists, journalism educators and a large segment of the global public. As the prolific body of empirical and theoretical research into this phenomenon continues to expand, however, “discourses of citizen journalism reveal an array of virtues in the opinion of advocates striving to transform journalism by improving its civic contribution to public life – and conceal a multitude of sins in the eyes of critics intent on preserving what they perceive to be the integrity of professional practice – in complex, occasionally contradictory ways” (Allan 2013: 8). This chapter offers a necessary critical overview of citizen journalism in its many forms and shapes, with a focus on its promises and perils and what it means for the future of news. We will start with a review of the concept of “citizen journalism” and its many alternative terms, then move to brief note on the long history of citizen journalism, which dates back to the early days of the printing press. This will be followed by our typology of three major forms of citizen journalism (CJ) – citizen witnessing, oppositional CJ and expertise-based CJ – along an assessment of each form’s primary actions, motives, functions and influences. The penultimate part of the chapter will focus on CJ’s flaws and pitfalls – especially the mis/disinformation environment it fosters and the “dialogue of the deaf” it engenders – and place them in the context of the post-truth era to highlight the still critical need for professional journalists. The chapter concludes with a brief review of the understandably but unnecessarily uneasy relationship between citizen and professional journalism and calls for the latter to adopt a new attitude to work well with the former

Fragility and Empowerment: Community Television in the Digital Era

The advent of television technologies has significantly restructured the context within which community television producers operate. Digital technologies have undercut “spectrum scarcity” arguments for limiting access to distribution platforms and opened up new paths to reach audiences. It has also, however, seen a decline in some of the regulatory structures that provided protection to noncommercial providers in eras of spectrum scarcity. The rise of the prosumer has, in its focus on production by individuals, weakened some of the underpinnings (economic and ideological) for community-based production, with consequent challenges for the sustainability of these often precarious projects. In this article, we tease out the implications of digitization for community television operators, exploring the state of the sector in the liberal North Atlantic region, and compare “traditional” community channels with “newer” channels that have emerged in the digital context in the past two decades. Our study explores the opportunities and challenges that face the sector following the transition to digital model

Sustainable community media: The challenge of upholding the public trust

Editorial for the thematic issue on "Sustaining Community Media: Challenges and Strategies

Neurite Orientation Dispersion and Density Imaging Color Maps to Characterize Brain Diffusion in Neurologic Disorders

Purpose: Neurite orientation dispersion and density imaging (NODDI) has recently been developed to overcome diffusion technique limitations in modeling biological systems. This manuscript reports a preliminary investigation into the use of a single color-coded map to represent NODDI-derived information. Materials and methods: An optimized diffusion-weighted imaging protocol was acquired in several clinical neurological contexts including demyelinating disease, neoplastic process, stroke, and toxic/metabolic disease. The NODDI model was fitted to the diffusion datasets. NODDI is based on a three-compartment diffusion model and provides maps that quantify the contributions to the total diffusion signal in each voxel. The NODDI compartment maps were combined into a single 4-dimensional volume visualized as RGB image (red for anisotropic Gaussian diffusion, green for non-Gaussian anisotropic diffusion, and blue for isotropic Gaussian diffusion), in which the relative contributions of the different microstructural compartments can be easily appreciated. Results: The NODDI color maps better describe the heterogeneity of neoplastic as well inflammatory lesions by identifying different tissue components within areas apparently homogeneous on conventional imaging. Moreover, NODDI color maps seem to be useful for identifying vasogenic edema differently from tumor-infiltrated edema. In multiple sclerosis, the NODDI color maps enable a visual assessment of the underlying microstructural changes, possibly highlighting an increased inflammatory component, within lesions and potentially in normal-appearing white matter. Conclusion: The NODDI color maps could make this technique valuable in a clinical setting, providing comprehensive and accessible information in normal and pathological brain tissues in different neurological pathologies

Longitudinal phase-space manipulation with beam-driven plasma wakefields

The development of compact accelerator facilities providing high-brightness beams is one of the most challenging tasks in field of next-generation compact and cost affordable particle accelerators, to be used in many fields for industrial, medical and research applications. The ability to shape the beam longitudinal phase-space, in particular, plays a key role to achieve high-peak brightness. Here we present a new approach that allows to tune the longitudinal phase-space of a high-brightness beam by means of a plasma wakefields. The electron beam passing through the plasma drives large wakefields that are used to manipulate the time-energy correlation of particles along the beam itself. We experimentally demonstrate that such solution is highly tunable by simply adjusting the density of the plasma and can be used to imprint or remove any correlation onto the beam. This is a fundamental requirement when dealing with largely time-energy correlated beams coming from future plasma accelerators

Temperature analysis in the shock waves regime for gas-filled plasma capillaries in plasma-based accelerators

Plasma confinement represents a crucial point for plasma-based accelerators and plasma lenses because it can strongly affect the beam properties. For this reason, an accurate measurement of the plasma parameters, as plasma temperature, pressure and electron density, must be performed. In this paper, we introduce a novel method to detect the plasma temperature and the pressure for gas-filled capillaries in use at the SPARC-LAB test facility. The proposed method is based on the shock waves produced at the ends of the capillary during the gas discharge and the subsequent plasma formation inside it. By measuring the supersonic speed of the plasma outflow, the thermodynamic parameters have been obtained both outside and inside the capillary. A plasma temperature around 1.4 eV has been measured, that depends on the geometric properties and the operating conditions of the capillary

TM oxides coatings for high demanding accelerator components

Large electric gradients are required for a variety of new applications, notably including the extreme high brightness electron sources for X-ray free electron lasers (FELs), RF photoinjector, industrial and medical accelerators and linear accelerators for particle physics colliders. In the framework of a INFN-LNF, SLAC (USA), KEK (Japan), UCLA (Los Angeles) collaboration, the Laboratori Nazionali di Frascati (LNF) is involved in the modelling, development and test of RF structures devoted to acceleration with high gradient electric field of particles through metal device. In order to improve the maximum sustainable gradients in normal conducting RF accelerating structures, we had to minimize the breakdown and the dark current. To this purpose the study of new materials and manufacturing techniques is mandatory to identify solutions to such extremely demanding applications. We considered the possibility to coat copper (and other metals) with a relatively thick film to improve and optimize breakdown performances. We present here the first characterization of MoO3 films deposited on copper by pulsed-laser deposition (PLD) starting from a commercial MoO3 target