Number of walks and degree powers in a graph

This note deals with the relationship between the total number of $k$-walks in a graph, and the sum of the $k$-th powers of its vertex degrees. In particular, it is shown that the the number of all $k$-walks is upper bounded by the sum of the $k$-th powers of the degrees

El ciclo porcino y sus indicadores : período 1980 - 1991

p.49-57El análisis económico de la producción porcina de la Argentina en el período comprendido entre los año 1980 y 1991 demuestra 3 variaciones cíclicas, así como la estacionalidad de la producción con un máximo de cabezas comercializadas en agosto hasta noviembre y un descenso a partir de diciembre hasta julio. El número de cabezas de ganado porcino comercializado disminuyó considerablemente a lo largo de estos 12 años, así como también el volumen registrado en el M ercado de Liniers del 61 por ciento al 20 por ciento. Los precios en cambio sufrieron un leve aumento. Se estudiaron como indicadores del ciclo porcino la relación porcino-maíz, porcino-sorgo, porcino-vacuno, porcino-pollo y porcino-reproductores vendidos en Palermo. De el análisis estadístico de los indicadores sólo se observa altas correlaciones entre el precio de los reproductores en Palermo-precio de los capones del mismo año en Liniers

Application of μ-Raman spectroscopy to the study of the corrosion products of archaeological coins

In this paper, a study of the corrosion products formed on archaeological bronze artefacts excavated in Tharros (Sardinia, Italy) is presented. The investigation was carried out by means of the combination of different analytical techniques, including optical microscopy, micro-Raman spectroscopy (µ-RS), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and X-ray diffraction. The artefacts under study are three bronze coins from the Phoenician-Punic period that are deeply corroded due to the chloride-rich soil of the Tharros excavation site. µ-Raman spectroscopy was chosen to investigate the corroded surfaces of the artefacts because it is a non-destructive technique, it has high spatial resolution, and it makes it possible to discriminate between polymorphs and correlate colour and chemical composition. Through µ-RS, it was possible to identify different mineralogical phases and different polymorphs, such as cuprite (Cu2O), copper trihydroxychloride [Cu2Cl(OH)3] polymorphs, hydroxy lead chloride laurionite [PbCl(OH)] and calcium carbonate polymorph aragonite. The experimental findings highlight that micro-Raman spectroscopy can be used to provide further knowledge regarding the environmental factors that may cause the degradation of archaeological bronzes in soil

Micro-Raman investigation of dangerous corrosion products of archaeological bronzes from Tharros (Sardinia-Italy)

A large number of bronze artefacts have been found during archaeological excavations carried out at Tharros (Sardinia, Italy). The composition of corrosion products have been determined by the combined use of optical microscopy (OM), micro-Raman spectroscopy (μ-Raman), scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). In particular, we will use μ-Raman spectroscopy to identify the corrosion products of natural patinas. This technique is equivalent or sometimes more efficient than microscopic and diffraction techniques to identify archaeological corrosion products. It is able to discriminate between different polymorphs, has a high spatial resolution and assures a correlation between the colour and the mineralogical nature. Furthermore has the advantage of being a nondestructive technique, quality highly valued in the cultural heritage

Accretion and photodesorption of CO ice as a function of the incident angle of deposition

Non-thermal desorption of inter- and circum-stellar ice mantles on dust grains, in particular ultraviolet photon-induced desorption, has gained importance in recent years. These processes may account for the observed gas phase abundances of molecules like CO toward cold interstellar clouds. Ice mantle growth results from gas molecules impinging on the dust from all directions and incidence angles. Nevertheless, the effect of the incident angle for deposition on ice photo-desorption rate has not been studied. This work explores the impact on the accretion and photodesorption rates of the incidence angle of CO gas molecules with the cold surface during deposition of a CO ice layer. Infrared spectroscopy monitored CO ice upon deposition at different angles, ultraviolet-irradiation, and subsequent warm-up. Vacuum-ultraviolet spectroscopy and a Ni-mesh measured the emission of the ultraviolet lamp. Molecules ejected from the ice to the gas during irradiation or warm-up were characterized by a quadrupole mass spectrometer. The photodesorption rate of CO ice deposited at 11 K and different incident angles was rather stable between 0 and 45$^{\circ}$. A maximum in the CO photodesorption rate appeared around 70$^{\circ}$-incidence deposition angle. The same deposition angle leads to the maximum surface area of water ice. Although this study of the surface area could not be performed for CO ice, the similar angle dependence in the photodesorption and the ice surface area suggests that they are closely related. Further evidence for a dependence of CO ice morphology on deposition angle is provided by thermal desorption of CO ice experiments

Nature-Inspired Interconnects for Self-Assembled Large-Scale Network-on-Chip Designs

Future nano-scale electronics built up from an Avogadro number of components needs efficient, highly scalable, and robust means of communication in order to be competitive with traditional silicon approaches. In recent years, the Networks-on-Chip (NoC) paradigm emerged as a promising solution to interconnect challenges in silicon-based electronics. Current NoC architectures are either highly regular or fully customized, both of which represent implausible assumptions for emerging bottom-up self-assembled molecular electronics that are generally assumed to have a high degree of irregularity and imperfection. Here, we pragmatically and experimentally investigate important design trade-offs and properties of an irregular, abstract, yet physically plausible 3D small-world interconnect fabric that is inspired by modern network-on-chip paradigms. We vary the framework's key parameters, such as the connectivity, the number of switch nodes, the distribution of long- versus short-range connections, and measure the network's relevant communication characteristics. We further explore the robustness against link failures and the ability and efficiency to solve a simple toy problem, the synchronization task. The results confirm that (1) computation in irregular assemblies is a promising and disruptive computing paradigm for self-assembled nano-scale electronics and (2) that 3D small-world interconnect fabrics with a power-law decaying distribution of shortcut lengths are physically plausible and have major advantages over local 2D and 3D regular topologies

eHealth literacy scale: a nursing analysis and Italian validation

Background: One of the scales most used to measure quickly and easily eHealth Literacy is the eHealth LiteracyScale (eHEALS); however, there was no validation of this scale in Italian. Therefore, the aim of this study was to adapt and validate the eHealth Literacy Scale (eHEALS) to the italian context. Methods: Italian translation of eHEALS was administered along unit to another two scale for measure lifestyle habits self-esteem and life satisfaction). A sample of 650 university students aged between 18 and 45 years was selected. An exploratory factor analysis, confirmatory factor analysis, analysis of invariance, reliability, stability and bivariate correlations were performed. Results: Exploratory factor analysis revealed a monofactorial structure that explained 67% of variance. Reliability of 0.87 and test-retest correlation of 0.78 was obtained. The questionnaire was invariant by gender. Regarding the criterion validity, a statistically significant and positive correlations between 0.05 and 0.15 with three indicators was obtained (self-esteem, lifestyle habits and life satisfaction). The italian version of the eHEALS tested in this work has shown to be a valid and reliable scale to measure eHealth competence in university students