518 research outputs found
Pectoral Muscle Hematoma After Axillary Artery Catheterization in a Patient Undergoing Minimally Invasive Mitral Valve Surgery
No full textImprese, istituzioni e processi innovativi. Un’analisi relazionale delle collaborazioni per l’innovazione nel cluster aerospaziale del Lazio
No full textMeasurements and removal of substrate effects on the microwave surface impedance of YBCO films on SrTiO3
No full textWe reconsider the problem of the measurements of the microwave complex surface impedance in thin superconducting films deposited on SrTiO3 substrates. We perform measurements of the complex surface impedance Z(s)(') = R-s(') + i Delta X-s(') of thin YBa2Cu3O7-delta films deposited by laser ablation on SrTiO3 substrates. The typical oscillations due to the strong temperature variation of the SrTiO3 permittivity are confirmed in R-s(') and observed in Delta X-s('). The effects of the SrTiO3 substrate are evident even well below the superconducting transition temperature of YBa2Cu3O7-delta. Similarly to previous works, we describe the overall response in terms of impedance transformations. We extend the known results by (i) considering the measurements of the imaginary part, (ii) comparing the measurements to the absolute dc resistivity measured on the same sample, and (iii) suggesting a method for measuring the intrinsic thin film surface impedance by adjusting the substrate impedance. To demonstrate the feasibility of microwave measurements of intrinsic properties of films grown onto SrTiO3 substrates, we check the proposed method by measuring the field dependent surface impedance before and after removal of the substrate resonance
Knowledge Transfer and Internet Technology in Industrial Districts
No full textThe major aim of this paper is to analyse how Internet
can impact on knowledge transfer in Industrial Districts
(IDs). In order to achieve this goal after the description of
principal IDs characteristics and of the knowledge
transfer process in IDs we summarise the degree of
adoption of Internet technologies in Italian IDs and finally
we transpose the knowledge transfer model in the web
scenario. In the conclusions we highlight the main causes
of resistance to the adoption of Internet in IDs
Two novel approaches to study arthropod anatomy by using dualbeam FIB/SEM. Corresponding author
No full textTransmission Electron Microscopy (TEM) has always been the conventional method to study arthropod ultrastructure, while the use of Scanning Electron Microscopy (SEM) was mainly devoted to the examination of the external cuticular structures by secondary electrons. The new generation field emission SEMs are capable to generate images at sub-cellular level, comparable to TEM images employing backscattered electrons. The potential of this kind of acquisition becomes very powerful in the dual beam FIB/SEM where the SEM column is combined with a Focused Ion Beam (FIB) column. FIB uses ions as a nano-scalpel to slice samples fixed and embedded in resin, replacing traditional ultramicrotomy. We here present two novel methods, which optimize the use of FIB/SEM for studying arthropod anatomy
The explosive defensive system of paussine and brachinine bombardier beetles (Coleoptera Carabidae): comparative morphology and ultrastructure
No full textThe ground beetle subfamilies Paussinae and Brachininae, have always been of interest to scientists because of their ability to explosively eject a hot (up to 100°C) and irritating quinonoid secretion from pygidial glands, in response to attack by predators. The peculiarity of this defensive system led many scientists to consider "bombardier beetle" as a monophyletic lineage, emphasizing the general similarities in morphology, function and chemical reactions, despite the different ways of ejecting the spray (directing the abdomen in brachinines; using the elytral flange of Coanda in paussines). However, studies concerning fine morphology and ultrastructure of the components of the pygidial defensive systems (reaction chambers, valves, ducts, reservoirs, and glands that secrete H2O2, hydroquinones, catalases and peroxidases) are still lacking (paussines) or incomplete (brachinines). In order to render these issues available to a comparative advanced discussion, we performed a morphological and ultrastructural study of representative species belonging to the genera: Metrius (Metriini), Pachyteles and Goniotropis (Ozaenini), and Paussus (Paussini) for Paussinae; and Brachinus and Pheropsophus (Brachinini) for Brachininae. Samples were examined through optical microscopy (dissections, classical histology), scanning (SEM) and transmission (TEM) electron microscopy, and focused ion beam (FIB) microscopy. The relative parts of the defensive systems for each paussine and brachinine species were described, illustrated and comparatively analyzed. We found significant differences between the two systems at both cellular and microstructural levels. Our preliminary results raise some challenges to the acknowledged hypothesis of evolution of this peculiar defensive system that parallel other evidences on the relationship between paussines and brachinines
Functional anatomy of the explosive defensive system of bombardier beetles (Coleoptera, Carabidae, Brachininae). Corresponding author
No full textThis paper provides the first comparative anatomical study of the explosive pygidial defensive system of bombardier beetles in species classified in three brachinine subtribes: Brachinus (Brachinina), Pheropsophus (Pheropsophina) and Aptinus (Aptinina). We investigated the morphology and ultrastructure of this system using optical, fluorescence, and focused ion beam (FIB/SEM) microscopy. In doing so, we characterized and comparatively discussed: (1) the ultrastructure of the gland tissues producing hydroquinones and hydrogen peroxide (secretory lobes), and those producing catalases and peroxidases (accessory glands); (2) the complex anatomy of the collecting duct; (3) the arrangement of the muscular bundles and the folding of the cuticle of the reservoir, suggesting a functional division of this chamber (dynamic part and storage part); (4) the great structural diversity of sculpticles inside the reaction chamber, where we could recognize six main types of microsculpture located in specific districts of the chamber. Additionally, using fluorescence microscopy, we highlighted the presence of resilin in two structures strongly subjected to mechanical stress during the discharge, the valve and the turrets of the reaction chamber. The results of this paper give a solid anatomic overview of the most popular beetle defensive system, contributing to the debate on its evolution within the Carabidae
Organizational Consequences of E-mail Adoption and Diffusion: Theoretical Issues and Empirical Results
No full textThe actual use of e-mail communication in organisations presents a lot of surprising figures, and as such it is a far from being a well known technology when considering its social effects. In the filed of computer-mediated communication technologies our results confirm Emergent Approaches, and more generally Giddens’ structuration theory: the actual use of a technology is context-dependent, and they are embedded in a recursive interaction. Among the many surprising findings, we can mention that: no substitution effects between e-mail and face-to-face have been found, neither any implicit organisation’s democratisation; e-mail is more used to communicate with close than distant colleagues; northern people use e-mail in a different way from Southern people. From a methodological standpoint, our research is the most extensive, systematic and complete ever done. However, considering the huge amount of quantitative and qualitative collected data, present results should be regarded just as preliminary ones
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