Radionuclides Transport Phenomena in Vadose Zone

Radioactive waste management is fundamental to safeguard population and environment by radiological risks. Environmental assessment of a site, where nuclear activities are located, allows understanding the hydro geological system and the radionuclides transport in groundwater and subsoil. Use of dedicated software is the basis of transport phenomena investigation and for dynamic scenarios prediction; this permits to understand the evolution of accidental contamination events, but at the same time the potentiality of the software itself can be verified. The aim of this paper is to perform a numerical analysis by means of HYDRUS 1D code, so as to evaluate radionuclides transport in a nuclear site in Piedmont region (Italy). In particular, the behaviour in vadose zone was investigated. An iterative assessment process was performed for risk assessment of radioactive contamination. The analysis therein developed considers the following aspects: i) hydro geological site characterization; ii) individuation of the main intrinsic and external site factors influencing water flow and radionuclides transport phenomena; iii) software potential for radionuclides leakage simulation purposes

The Efficiency of Question-Asking Strategies in a Real-World Visual Search Task

In recent years, a multitude of datasets of human–human conversations has been released for the main purpose of training conversational agents based on data-hungry artificial neural networks. In this paper, we argue that datasets of this sort represent a useful and underexplored source to validate, complement, and enhance cognitive studies on human behavior and language use. We present a method that leverages the recent development of powerful computational models to obtain the fine-grained annotation required to apply metrics and techniques from Cognitive Science to large datasets. Previous work in Cognitive Science has investigated the question-asking strategies of human participants by employing different variants of the so-called 20-question-game setting and proposing several evaluation methods. In our work, we focus on GuessWhat, a task proposed within the Computer Vision and Natural Language Processing communities that is similar in structure to the 20-question-game setting. Crucially, the GuessWhat dataset contains tens of thousands of dialogues based on real-world images, making it a suitable setting to investigate the question-asking strategies of human players on a large scale and in a natural setting. Our results demonstrate the effectiveness of computational tools to automatically code how the hypothesis space changes throughout the dialogue in complex visual scenes. On the one hand, we confirm findings from previous work on smaller and more controlled settings. On the other hand, our analyses allow us to highlight the presence of “uninformative” questions (in terms of Expected Information Gain) at specific rounds of the dialogue. We hypothesize that these questions fulfill pragmatic constraints that are exploited by human players to solve visual tasks in complex scenes successfully. Our work illustrates a method that brings together efforts and findings from different disciplines to gain a better understanding of human question-asking strategies on large-scale datasets, while at the same time posing new questions about the development of conversational systems.</p

Neutronic comparison of liquid breeders for ARC-like reactor blankets

The proposed blanket for Affordable Robust Compact (ARC) reactor is one of the simplest blanket concepts. It is a bulk tank filled with a lithium and beryllium fluorides molten salt. The fluid effectively works as tritium breeder, vessel coolant and neutron moderator and shield. However, despite the simplicity of the concept, the compactness of the reactor constitutes a novelty in the fusion field. It is thus necessary to evaluate all the possible solutions for an effective blanket component. This work analyses different liquid blanket identifying the most suitable for a compact fusion reactor. More specifically, the study addresses the capability of breeding tritium in a compact solution, actively shielding the coils and reducing the radioactive waste. Findings are that FLiBe optimizes the most the system in terms of applicability, tritium breeding, compactness and activation. Nonetheless, there is no lack of backup choices. For instance, there are hints that lithium-zirconium fluoride salts could accomplish the blanket main tasks in a compact reactor too. Leaving PbLi as inefficient, but cheap and still virtually viable solution

Drivers of success in implementing sustainable tourism policies in urban areas

The existing literature in the field of sustainable tourism highlights a number of barriers that impede the implementation of policies in this area. Yet, not many studies have so far considered the factors that would contribute to putting this concept into practice, and few address the case of urban areas. The concept of sustainability has only received limited attention in urban tourism research, even though large cities are recognised as one of the most important tourist destinations that attract vast numbers of visitors. Adopting a case study approach, this paper discusses a number of drivers of success identified by policy-makers in London to contribute to the implementation of sustainable tourisms policies at the local level, and briefly looks at the relationship between these drivers and the constraints perceived by the respondents to hinder the implementation of such policies in practice. These findings may help policy-makers in other large cities to successfully develop and implement policies towards sustainable development of tourism in their area

Systemic sclerosis cutaneous expression: Management of skin fibrosis and digital ulcers

Systemic sclerosis is a connective tissue disease with cutaneous involvement. Clinical manifestations result from the balance of inflammations/autoimmunity process and fibrogenesis. Patients suffer from skin ulcers, non-ulcerative lesions including digital pitting scars, telangiectasias, subungual hyperkeratosis, abrasions, fissures, and subcutaneous calcinosis. A review about the pathophysiology of the disease, the physical examination of the patients, the instrumental assessment, and possible treatments is performed