Evidence of a structural anomaly at 14 K in polymerised CsC60

We report the results of a high-resolution synchrotron X-ray powder diffraction study of polymerised CsC$_{60}$ in the temperature range 4 to 40 K. Its crystal structure is monoclinic (space group I2/m), isostructural with RbC$_{60}$. Below 14 K, a spontaneous thermal contraction is observed along both the polymer chain axis, $a$ and the interchain separation along [111], $d_1$. This structural anomaly could trigger the occurrence of the spin-singlet ground state, observed by NMR at the same temperature.Comment: 8 pages, 5 figures, submitte

Multiscale Bone Remodelling with Spatial P Systems

Many biological phenomena are inherently multiscale, i.e. they are characterized by interactions involving different spatial and temporal scales simultaneously. Though several approaches have been proposed to provide "multilayer" models, only Complex Automata, derived from Cellular Automata, naturally embed spatial information and realize multiscaling with well-established inter-scale integration schemas. Spatial P systems, a variant of P systems in which a more geometric concept of space has been added, have several characteristics in common with Cellular Automata. We propose such a formalism as a basis to rephrase the Complex Automata multiscaling approach and, in this perspective, provide a 2-scale Spatial P system describing bone remodelling. The proposed model not only results to be highly faithful and expressive in a multiscale scenario, but also highlights the need of a deep and formal expressiveness study involving Complex Automata, Spatial P systems and other promising multiscale approaches, such as our shape-based one already resulted to be highly faithful.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005

Muon spin rotation and relaxation in magnetic materials

A review of the muon spin rotation and relaxation ($\mu$SR) studies on magnetic materials published from July 1993 is presented. It covers the investigation of magnetic phase diagrams, of spin dynamics and the analysis of the magnetic properties of superconductors. We have chosen to focus on selected experimental works in these different topics. In addition, a list of published works is provided.Comment: Review article, 59 pages, LaTeX with IoP macro

A multi-stage model for dielectric barrier discharge in atmospheric pressure air

In this paper, a multi-stage numerical methodology for the description of the Dielectric Barrier Discharge physics in air is discussed. The behavior of the heavy species is computed using drift-diffusion equations. Electrons are taken into account by solving a non-linear formulation of electrostatics. The physical effects of the steamer discharges are modelled by means of a simplified 0D approach. The model also includes a semi-implicit 0D model for the assessment of the elementary chemical processes occurring in air. The developed methodology is employed for the simulation of a volumetric Dielectric Barrier Discharge reactor. The obtained species number density and surface charge deposition rates and are shown and discussed

Evidence for distinct polymer chain orientations in KC60 and RbC60

The KC60 and RbC60 polymer phases exhibit contrasting electronic properties while powder diffraction studies have revealed no definite structural difference. We have performed single crystal X-ray diffraction and diffuse scattering studies of these compounds. It is found that KC60 and RbC60 possess different chain orientations about their axes, which are described by distinct space groups Pmnn and I2/m, respectively. Such a structural difference will be of great importance to a complete understanding of the physical properties.Comment: To be published in Phys. Rev. Let

Epífitos vasculares predominantes em zonas ecológicas de forófitos, Santa Catarina, Brasil.

Espécies epifíticas apresentam formas, dimensões e biomassa distintas e colonizam os forófitos em regime temporário ou permanente. O presente trabalho teve como objetivo avaliar a distribuição de epífitos vasculares de biomassa visualmente dominante nas zonas ecológicas dos forófitos (fuste, copa interna e copa externa) da Floresta Ombrófila Densa de Santa Catarina. Os estudos foram realizados em 13 unidades amostrais, no interior das quais foram selecionados oito forófitos. Para a coleta dos dados, foi empregada a técnica de arvorismo e observação a partir do solo. De modo geral, as espécies registradas puderam ser classificadas como holoepífitos característicos e facultativos, e hemiepífitos primários e secundários. A família Bromeliaceae destacou-se dentre as demais nas três zonas ecológicas dos forófitos, reunindo as espécies com maiores biomassas. Relacionando as categorias ecológicas, os holoepífitos característicos, como bromeliáceas e orquidáceas, concentraram-se na região da copa e os hemiepífitos, como as aráceas Philodendron loefgrenii e Philodendron appendiculatum, foram encontradas geralmente na região do fuste.Edição especial: II Seminário sobre Inventário Florestal

Increase in airborne allergenic pollen in Trentino (North Italy) over a 30-year period (1989-2018) is connected to temperature rise

The aim of this study is to verify if changes occurred in the seasonality and yearly amounts of airborne pollen in San Michele all’Adige - Northern Italy, and to evaluate their relation with climate change-related variables, such as air temperatures and frost days in the period 1989 - 2018. The study of airborne pollen and its spatio-temporal changes is highly important due to the allergenicity of many pollen taxa. The pollen allergy, in fact, interests 25-40% of population, globally, and displays an increasing trend. Climate change may impact pollen allergenicity and production, as well as plant distribution, with the potential spread of neophytes that produce allergenic pollen. The main hypothesis of our research is that climate change impacting our study area influences pollen dispersal in the atmosphere, and therefore on human-health related issues. Airborne pollen was collected using a volumetric Hirst-type aerobiological sampler (Lanzoni VPPS 2000), and the daily concentration of airborne pollen (P*m-3 ) was calculated for a total of 24 arboreal (AP; trees and shrubs) and non-arboreal pollen taxa (NAP; herbaceous) over a 30- year period. The sampling and analysis of airborne pollen have been performed in accordance with the UNI EN 16868:2019 European standard procedure. The main pollen season (MPS) descriptors were calculated for each taxon. The presence of a monotonic upward or downward temporal trend in pollen season descriptors was verified (non-parametric Mann-Kendall test) and changes were analyzed in relation to air temperature, precipitation, and land use; in addition, pollen data were analyzed clustered into three decadic blocks (non-parametric Kruskal-Wallis ANOVA) to minimize interannual fluctuations and maximize relevant change signals. The major change observed during the study period was the significant increase in annual pollen integral (APIn). This change is strongly emphasized when analyzing the pollen data in three decadic blocks, both for all the considered taxa (+58%) and for Arboreal Pollen (AP; +155%). When considering single taxa, APIn shows a significant positive trend for Cupressaceae/Taxaceae, Ulmus, Populus, Salix, Ostrya, Quercus, Olea, Plantago, Cannabaceae, and Ambrosia; a significantly earlier start of the MPS is proved for Rumex and Poaceae. Cumulated APIn shows a significant positive correlation with annual T min (<0.005) and T mean (<0.001), both of which showing a significant increase, and a negative correlation (<0.025) with the number of frost days. The research demonstrates an increasingly larger amount of airborne pollen connected to climate change, such as rising temperatures and milder winter conditions in the study area, leading to a major threat to people suffering of pollen allergies

Modeling Study of Chemical Kinetics and Vibrational Excitation in a Volumetric DBD in Humid Air at Atmospheric Pressure

A zero-dimensionl model is developed to study the chemical kinetics of a volumetric dielectric barrier discharge (DBD) reactor operating with humid air at atmospheric pressure. This work focuses on the relation between molecular vibrational excitation, the plasma reactor input power and the number densities of several species that are known to play an important role in biomedical applications (e.g. O3,NO,NO2,..). A preliminary study is carried out to observe the influence of water molecules on the electron energy distribution function for different values of water concentration and reduced electric field. A simplified approach is then adopted to quantify the contribution of vibrationally-excited O2 molecules to NO formation. The results obtained using our detailed model suggest that for the physical conditions considered in this work O2 vibrational kinetics can be neglected without compromising the overall accuracy of the simulation. Finally, a reaction set is coupled with an equivalent circuit model to simulate the E-I characteristic of a typical DBD reactor. Different simulations were carried out considering different values of the average plasma input power densities. A particular focus was given to the influence of the Zeldovich mechanism on O3 and NOX production performing simulations where this reaction is not considered. The obtained results are shown and the role of vibrationally excited N2 molecules is discussed. The simulation results indicate also that N2 vibrational excitation, and more precisely the Zeldovich mechanism, has a larger effect on O3 and NOX production at intermediate input power levels