Un modello multi-hazard per la valutazione del rischio dei beni archeologici: il caso sperimentale della Villa Adriana di Tivoli

Compared with other objects of our cultural heritage, the various construction remains that belong to the ancient architectural heritage are generally associated with the most challenging problems with respect to their preservation. Difficulties and problems become unpaired when the ancient heritage is the assembly of several monumental constructions, as in the case of the imperial complex constructed by Adriano in Tivoli, known as Hadrian’s Villa. Under these circumstances, any risk analysis and subsequent study of preservation measures will require a two stage approach. In the first stage, a detailed knowledge of each single element or structure within the complex must be acquired. In the second stage the available knowledge pertaining to the various monuments must be combined and the entire complex combining the single architectural artifacts into a monumental unity must be re-examined with respect to its original status and its historical modifications. Hence a great wealth of information and a profound knowledge have been acquired on several monuments in this complex. Therefore, it is now possible to propose sound hypotheses on each one of these architectural artifacts as well as to propose an interactive data system for risk analyses and risk assessment with respect to the preservation of the complex. Taking the opportunity of the "Risk assessment map of the cultural heritage" compiled by the Central Institute for Restoration (ISCR), a research project was undertaken to develop an analysis model of the villa which would allow an estimation of the global risk of the various ancient structures. This project is based on the use of a GIS to develop a matrix of risk indexes as well as a database grouping all available information on the single monument. The development of this system will make it possible to cross reference the data acquired within the various fields of investigation involved in the survey phase, the preservation phase and the restoration process of each monumental unit and the complex as a whole

Electron-phonon interaction at the Be(0001) surface

We present a first principle study of the electron-phonon (e-p) interaction at the Be(0001) surface. The real and imaginary part of the e-p self energy are calculated for the surface state in the binding energy range from the $\bar{\Gamma}$ point to the Fermi level. Our calculation shows an overall good agreement with several photoemission data measured at high and low temperatures. Additionally, we show that the energy derivative of real part of the self-energy presents a strong temperature and energy variation close to $E_{F}$, making it difficult to measure its value just at $E_{F}$.Comment: Accepted in Phys. Rev. Lett., 5 figure

Structure and stability of graphene nanoribbons in oxygen, carbon dioxide, water, and ammonia

We determine, by means of density functional theory, the stability and the structure of graphene nanoribbon (GNR) edges in presence of molecules such as oxygen, water, ammonia, and carbon dioxide. As in the case of hydrogen-terminated nanoribbons, we find that the most stable armchair and zigzag configurations are characterized by a non-metallic/non-magnetic nature, and are compatible with Clar's sextet rules, well known in organic chemistry. In particular, we predict that, at thermodynamic equilibrium, neutral GNRs in oxygen-rich atmosphere should preferentially be along the armchair direction, while water-saturated GNRs should present zigzag edges. Our results promise to be particularly useful to GNRs synthesis, since the most recent and advanced experimental routes are most effective in water and/or ammonia-containing solutions.Comment: accepted for publication in PR

Structure, Stability, Edge States and Aromaticity of Graphene Ribbons

We determine the stability, the geometry, the electronic and magnetic structure of hydrogen-terminated graphene-nanoribbons edges as a function of the hydrogen content of the environment by means of density functional theory. Antiferromagnetic zigzag ribbons are stable only at extremely-low ultra-vacuum pressures. Under more standard conditions, the most stable structures are the mono- and di-hydrogenated armchair edges and a zigzag edge reconstruction with one di- and two mono-hydrogenated sites. At high hydrogen-concentration ``bulk'' graphene is not stable and spontaneously breaks to form ribbons, in analogy to the spontaneous breaking of graphene into small-width nanoribbons observed experimentally in solution. The stability and the existence of exotic edge electronic-states and/or magnetism is rationalized in terms of simple concepts from organic chemistry (Clar's rule)Comment: 4 pages, 3 figures, accepted for publication by Physical Review Letter

Polyhydroxyalkanoate (PHA): Review of synthesis, characteristics, processing and potential applications in packaging

Polyhydroxyalkanoates (PHAs) are gaining increasing attention in the biodegradable polymer market due to their promising properties such as high biodegradability in different environments, not just in composting plants, and processing versatility. Indeed among biopolymers, these biogenic polyesters represent a potential sustainable replacement for fossil fuel-based thermoplastics. Most commercially available PHAs are obtained with pure microbial cultures grown on renewable feedstocks (i.e. glucose) under sterile conditions but recent research studies focus on the use of wastes as growth media. PHA can be extracted from the bacteria cell and then formulated and processed by extrusion for production of rigid and flexible plastic suitable not just for the most assessed medical applications but also considered for applications including packaging, moulded goods, paper coatings, non-woven fabrics, adhesives, films and performance additives. The present paper reviews the different classes of PHAs, their main properties, processing aspects, commercially available ones, as well as limitations and related improvements being researched, with specific focus on potential applications of PHAs in packaging

Role of the microbiota in the modulation of vaccine immune responses

The human immune system and the microbiota co-evolve, and their balanced relationship is based on crosstalk between the two systems through the course of life. This tight association and the overall composition and richness of the microbiota play an important role in the modulation of host immunity and may impact the immune response to vaccination. The availability of innovative technologies, such as next-generation sequencing (NGS) and correlated bioinformatics tools, allows a deeper investigation of the crosstalk between the microbiota and human immune responses. This review discusses the current knowledge on the influence of the microbiota on the immune response to vaccination and novel tools to deeply analyze the impact of the microbiome on vaccine responses

Molecular mechanisms of the acute kidney injury to chronic kidney disease transition: An updated view

Increasing evidence has demonstrated the bidirectional link between acute kidney injury (AKI) and chronic kidney disease (CKD) such that, in the clinical setting, the new concept of a unified syndrome has been proposed. The pathophysiological reasons, along with the cellular and molecular mechanisms, behind the ability of a single, acute, apparently self-limiting event to drive chronic kidney disease progression are yet to be explained. This acute injury could promote progression to chronic disease through different pathways involving the endothelium, the inflammatory response and the development of fibrosis. The interplay among endothelial cells, macrophages and other immune cells, pericytes and fibroblasts often converge in the tubular epithelial cells that play a central role. Recent evidence has strengthened this concept by demonstrating that injured tubules respond to acute tubular necrosis through two main mechanisms: The polyploidization of tubular cells and the proliferation of a small population of self-renewing renal progenitors. This alternative pathophysiological interpretation could better characterize functional recovery after AKI

Correlation between physical activity and sedentary behavior with healthy and unhealthy behaviors in Italy and Tuscan region: a cross sectional study

Introduction. Regular physical activity (PA) has associated with various positive health aspects such as a decreased risk of chronic or generic illnesses, furthermore, a sedentary lifestyle has been asso- ciated with health problems such as obesity. To examine the rela- tionship between patterns of PA, screen-based media use (SBM) and social health indicators within a specific demographic group and highlight the regional vs. national differences in these relationships. Methods. The data is drawn from the Health Behaviour in School-Aged Children (HBSC) database, a national cross-sec- tional survey in a representative sample (N = 3920) of students aged 11-13-15 years and compared to those of the Tuscan region (N = 3381). Variables considered other than PA and SBM use includes positive health indicators such as physical health status, quality of family and peer relationships, fruit consumption, break- fast consumption as well as negative health indicators, such as health complaints, smoking and alcohol use. Results. Some positive health indicators showed a positive cor- relation with PA. Students adopting healthy behaviours often met the Physical Activity Guide Line (PAGL). On the contrary, negative health indicators were associated with PAGL in a neg- ative way. In general SBM was positively related to several of the negative health indicators and vice versa. SBM was related in a positive fashion to tobacco use that repre- sents a protective factor. Discussion. The results show that met PAGL is associated with positive health indicators and that high levels of SBM use is asso- ciated with negative health indicators. The study also emphasizes the relationship between PA, SBM use and social factors. Increas- ing PA and decreasing SBM use should be an aim in general health behaviour promotion