Riconnessione magnetica in presenza di un profilo di velocità iniziale.

Sviluppo di un modello matematico per il calcolo del tasso di crescita dell'instabilita' Tearing in plasma con un profilo nel campo di velocita' all'equilibrio Kelvin-Helmholtz (KH) stabile. La motivazione di questo lavoro riguarda due aspetti: uno puramente teorico, volto a completare le possibili configurazioni dei campi di velocita' e magnetici nei fenomeni fisici. L'altro consiste nel diffuso intreresse, riscontrato nei numerosi articoli presenti in letteratura dei plasmi, sui fenomeni di trasporto e mixing, indotti dalla KH e riconnessione, nella magnetosfera

Indicators: Syntactic Vision and Semantic Vision: First Part (Indicadores: la Visión Sintáctica y la Visión Semántica: Primera Parte)

In this essay several aspects of the concept ‘indicator’ are criticized, as well as the technical consequences of those misconceptions. The most relevant among them is the pretence of measuring the validity of an indicator, e. g. the degree of semantic correspondence between the indicator and  the concept which it is supposes to refer to. 

Glass Façades with High Performance and Low Impact. Towards an Integrated Approach.

For centuries, the main functionality of glass elements in façades has been to meet three principal requirements: to let in daylight, to grant a direct view of the immediate surroundings and, at the same time, to provide protection against wind and rain. The use of glass in architectural applications, especially in façades, has spread recently, in order to meet the current trends of lightness, robustness and energy efficiency. The glass is also suitable to be used in historical contexts, or in general, in redevelopment of existing buildings or areas. The aim is often to create a transparent, airy and light building, providing a futuristic outlook. The present research, divided into two sections, aims to identify the major methodological issues to support the development of glass façades design and construction process. The purpose is to support the architectural designer to consider the issues, the available solutions and the main elements to be evaluated in the choice of a glass façade, especially in the early stages of design. The thesis introduces the aspects of integration, identifies some of the key challenges and unfolds a scenario for a novel approach to environmentally sustainable glass systems. The purpose is to facilitate high performance/low impact architecture, where high performance is meant to include sustainability in this context. Part of the research study has been developed during a research period at the Glass and Façades Technology Research Group (gFT) based at the University of Cambridge under the supervision of Dr. Mauro Overend. The main focus during the research period has been the development of a process map for glass façades intended for renovation projects

Recent developments in the reduction of oxidative stress through antioxidant polymeric formulations

Reactive oxygen and nitrogen species (RONS) are produced endogenously in our body, or introduced through external factors, such as pollution, cigarette smoke, and excessive sunlight exposure. In normal conditions, there is a physiological balance between pro-oxidant species and antioxidant molecules that are able to counteract the detrimental effect of the former. Nevertheless, when this homeostasis is disrupted, the resulting oxidative stress can lead to several pathological conditions, from inflammation to cancer and neurodegenerative diseases. In this review, we report on the recent developments of different polymeric formulations that are able to reduce the oxidative stress, from natural extracts, to films and hydrogels, and finally to nanoparticles (NPs)

Glycosystems in nanotechnology: Gold glyconanoparticles as carrier for anti-HIV prodrugs

The therapeutic approach for the treatment of HIV infection is based on the highly active antiretroviral therapy (HAART), a cocktail of antiretroviral drugs. Notwithstanding HAART has shown different drawbacks like toxic side effects and the emergence of viral multidrug resistance. Nanotechnology offers new tools to improve HIV drug treatment and prevention. In this scenario, gold nanoparticles are an interesting chemical tool to design and prepare smart and efficient drug-delivery systems. Here we describe the preparation and antiviral activity of carbohydrate-coated gold nanoparticles loaded with anti-HIV prodrug candidates. The nucleoside reverse transcriptase inhibitors abacavir and lamivudine have been converted to the corresponding thiol-ending ester derivatives and then conjugated to ~3 nm glucose-coated gold nanoparticles by means of “thiol-for-thiol” ligand place exchange reactions. The drugs-containing glyconanoparticles were characterized and the pH-mediated release of the drug from the nanoparticle has been determined. The antiviral activity was tested by evaluating the replication of NL4-3 HIV in TZM-bl infected cells. The proof-of-principle presented in this work aims to introduce gold glyconanoparticles as a new multifunctional drug-delivery system in the therapy against HIV

Sono equidistanti le categorie di una scala Likert? Alcune risultanze di ricerca

One obvious, minimal pre-requisite in order to use Likert scores as cardinal numbers in data analysis is that they be perceived as more or less equidistant along the dimension of interest. Already 50 years ago, Johann Galtung among others raised serious doubts about the possibility that respondents actually do consider “agree” and “disagree” as equidistant from “uncertain”, given the well-known frequency of acquiescent response sets. In 1973, Benzecri maintained that the technique he had just launched on the academic market (correspondence analysis) supplied an excellent means to also control the assumption of equidistance of one of Likert’s short answers from the two adjoining ones. In the nineties, three young Italian students applied Benzecri’s technique to three different samples of respondents, and found converging results, all widely apart from the assumed equidistance. This essay replicates their survey on a larger sample of Likert scales coming from a dozen different surveys. Unlike the previous controls, the results diverge largely from one another. Yet, only a few offer a mild support to the assumption of perceived equidistance, while in their majority the results raise all sorts of further doubts about it

Evaluation of Load transfer in rigid pavements by Rolling wheel deflectometer and Falling weight deflectometer

Rigid pavements have widespread use, e.g, in motorways and airports, due to their excellent properties such as high bearing capacity and long lifetime. However, when rigid pavements fail it is often due to bad load transfer efficiency (LTE) at its joints. Traditional methods of measuring LTE can be time consuming. Here, we study the possibility of measuring LTE using a moving load with the aim of achieving higher productivity. An experiment simulating Rolling Weight Deflectometer (RWD) measurements on a joint was carried out to gain understanding and confidence that can guide the analysis of real RWD data. Continuous data from measurements across a joint allows for determination of not only the LTE but also additional parameters characterizing the pavement and the joint. A semi-analytical model was implemented for simulating the pavement response next to a joint and used for interpretation and verification of the experimental data. The results show promise for the use of moving loads for rapid evaluation of joints

Il lavoro di Max Weber in America Latina e una reinterpretazione dei suoi contributi originali

The essay underlies that Max Weber’s ideas have been received in different ways in the various sociological schools in Latin America. His representation of the ideal type of a bureaucracy has been uniformly found con-sistent with the actual situations all around the continent. However, several authors vainly expected from him a general theory which could be adequately applied to the political processes characterizing the various nations in the continent. In particular, his two basic contributions to the philosophy of science (Wertbeziehung and Verursa-chung) have received much less attention than is concept of Wertfreiheit, loosely adopted by neo-positivists in order to justify their disinterest for class struggle and other social conflicts.En el ensayo se destaca como la acogida de las ideas de Weber en la América latina no fue uniforme: mientras su descripción de las características de la burocracia fue adoptada como perfectamente adecuada, la expectativa de una teoría global de la sociedad que pudiese aplicarse a las naciones del continente no fue satisfecha por la propuesta de un método para comprender y explicar procesos específicos. En particular, han sido descuidado sus dos conceptos revolucionarios bajo el punto di vista gnoseológico: (relación al valor) y (atribución a las causas).Il saggio passa in rivista la (diseguale) fortuna che le idee di Max Weber hanno incontrato in America Latina, sottolineando sia la piena adattabilità delle sue teorie sulla burocrazia, sia il fatto che da lui alcuni si attendevano una teoria globale della società applicabile agli sviluppi del secolo Ventesimo invece che un metodo per com-prendere e spiegare singoli processi. È stata in particolare sottovalutata l’importanza dei suoi due contributi gno-seologici fondamentali: il concetto di Wertbeziehung, che libera gli autori da pastoie scolastiche nella formula-zione dei concetti e nella scelta dei problemi da studiare, e di Verursachung, che sottolinea la libertà degli storio-grafi nella ricostruzione delle cause di un evento o di un processo

Active fillers’ effect on in situ performances of foam bitumen recycled mixtures

Cold recycling is one of the most employed rehabilitation techniques for asphalt pavements and it is becoming more and more important as reducing emissions becomes a priority in the reduction of the greenhouse effect. The main advantages of asphalt cold recycling techniques are the use of reclaimed materials and the fact that there is no need of aggregate heating to make the mixtures. This paper describes the evolution with time of in-situ performances of different foam bitumen-stabilised mixtures made with different active fillers (cement and lime), monitored during the first year from construction. Results are part of a more extensive research programme aimed to investigate the effects of using lime as an active filler in cold-recycled mixtures. Mixtures have been laid down on a specifically designed trial section in Italy, close to Florence. Short-term bearing capacity, immediately after construction, has been evaluated using a light weight deflectometer while to evaluate the mid-term performances falling weight deflectometer (FWD) tests have been performed after 24 hours, 14 days, 28 days and 9 months from construction. During these 9 months the test road was not opened to traffic, so the mixtures experienced almost no traffic (only construction traffic loads). This fact allowed to have the curing process without any influences other than the temperature: it means same curing conditions for all mixtures. Subsequent FWD tests are still ongoing to evaluate the evolution over time of pavement bearing capacity due to traffic. Results obtained positively support the use of lime as an active filler in the foam bitumen-stabilised material and allow to underline the effect of different active fillers in the material behaviour, even if all the mixtures underline excellent performances under traffic loading. FWD tests are scheduled to be repeated every 6 months in order to monitor the stiffness evolution of the mixtures and evaluate the nature of traffic damage