1,721,393 research outputs found
Fluids at interfaces: Casimir effect, depletion and thermo-osmosis.
Full text linkThe critical Casimir effect is the long-range interaction between two planar walls in a critical fluid due to the confinement, achieved by the wall interfaces, of the critical density fluctuations. In this Thesis we provide a microscopic description of the critical Casimir force, introducing a novel density functional approximation coupled to the hierarchical reference theory of fluids.
The depletion interaction is an effective attractive force arising between colloidal particles immersed in a solvent: The first prediction of this effect dates back to the seminal work by Asakura and Oosawa and has been obtained assuming that the colloidal particles were perfectly smooth spheres immersed in an ideal gas. In this Thesis we address the study of the interaction potential mediated by an ideal gas between two rough colloidal particles, as a function of the geometry, the dimension and the spatial configuration of the corrugations.
When a thermal gradient is applied to a fluid at contact with a surface a stationary flow develops. This effect, referred to as thermo-osmosis, has been discovered in the late nineteenth century but successful theoretical descriptions have been up to now devised only when the fluid is a rarefied gas. In this thesis we presents a microscopic theory of thermo-osmosis based on a generalisation of linear response theory to inhomogeneous and anisotropic environments and to thermal disturbances
Abuso di posizione dominante e tutela dell'accesso al farmaco: prospettive e limiti
Full text linkIl quesito attorno al quale si articola il lavoro è se nell'interpretazione del diritto della concorrenza vi sia spazio per accordare rilevanza a regole e aspettative condivise nella società in cui esso trova applicazione. La questione è importante perché tali regole ed aspettative, che nel lavoro vengono denominate "valori sociali", trovano oggi ostruite le proprie tradizionali vie di accesso alla tutela giuridica.
Si è quindi scelto di analizzare alcune recenti ipotesi di antitrust enforcement per verificare se il percorso interpretativo prospettato sia già stato intrapreso. Ciò ha reso necessario circoscrivere la domanda di ricerca al valore sociale "accesso al medicinale essenziale". Inoltre, l'analisi viene condotta in relazione alla sola fattispecie dell'abuso di posizione dominante, che, per svariati motivi, è più permeabile di altre ai valori sociali.
L'analisi empirica concerne quindi alcune ipotesi di condotte unilaterali anticoncorrenziali recentemente riscontrate nel settore farmaceutico, il cui comune denominatore risiede in una lettura dell'art. 102 TFUE socialmente utile: nei casi Aspen e Pfizer-Flynn le autorità garanti hanno ravvisato negli aumenti di prezzo praticati dalle imprese, palesemente finalizzati a sfruttare i consumatori di farmaci essenziali, due ipotesi di unfair pricing; nei casi AstraZeneca e Pfizer, invece, le imprese in posizione dominante sono incorse nei rigori del diritto della concorrenza in virtù del loro comportamento opportunistico, consistente in una manomissione del sistema regolatorio del brevetto farmaceutico che ha danneggiato concorrenti, pazienti-consumatori e servizi sanitari-clienti.
Al termine del percorso argomentativo la domanda riceve risposta positiva: l'antitrust ha conferito e può effettivamente conferire rilevanza a valori ed aspirazioni latenti nel tessuto sociale. Occorre, tuttavia, una precisazione: l'ermeneutica del diritto della concorrenza trova la propria cifra caratteristica nel carattere composito della fattispecie cui accede, rispetto alla quale la teoria economica svolge il ruolo fondamentale di co-definitrice della regola. Dovendo riflettere tale complessità, l'interpretazione non può limitarsi a tendere la lettera della norma in questo o quel senso, ma deve restituire una lettura economicamente solida della condotta d'impresa vietata. Ne deriva che la teoria economica concorre a tracciare le prospettive ed i limiti dell'antitrust rispetto alla tutela ai valori sociali.The thesis aims at assessing whether social values are or can become relevant to competition law interpretation, thus constituting a theoretical effort to grant those values a further way of satisfaction. The exploration of such new path has gained importance in the last decades, due to the decline of the legal concepts that have traditionally protected the most basic social aspirations.
The question needs, however, to be circumscribed if it is to be tested empirically. Therefore, the thesis focusses on whether access to essential drugs has gained relevance to the interpretation of the abuse of dominant position.
Following the specification of the question, a few recent cases characterized by a socially oriented application of Art. 102 TFEU are examined in depth. Notably, the analysis concerns two cases of unfair pricing (Aspen and Pfzer-Flynn), as they were obviously useful to contrast the exploitative behaviour of the firms against consumers of essential medicines, as well as two cases of regulatory gaming. In our view, the latters are to be considered significant attempts to fight the opportunistic strategies of firms, which are equally detrimental to competitors as well as to patients-consumers and health care systems-clients.
The analysis leads to the conclusion that competition law interpretation can, as suggested at the start of the essay, confer relevance to some shared aspirations running deep in the social context. An element needs, however, to be taken into due consideration: the hermeneutics of competition law find its distinctive mark in the complex nature of the norm, which is co-defined by law and economics, thus making it impossible to undertake a creative interpretative process while ignoring the identity of the forbidden conduct as elaborated by the economic theory. This leads to the conclusion that the boundaries of a socially oriented interpretation mainly identify with the limits of antitrust economics
How roughness affects the depletion mechanism
No full textWe develop a simple model, in the spirit of the Asakura-Oosawa theory, able to describe the effects of surface roughness on the depletion potential. The resulting explicit expressions are easily computed, without free parameters, for a wide range of physically interesting conditions. Comparison with recent numerical simulations [M. Kamp et al., Langmuir, 2016, 32, 1233] shows an encouraging agreement and allows predicting the onset of colloidal aggregation in dilute suspensions of rough particles. Furthermore, the model proves to be suitable to investigate the role of the geometry of the roughness
Solvent-mediated forces in critical fluids
No full textThe effective interaction between two planar walls immersed in a fluid is investigated by use of density functional theory in the supercritical region of the phase diagram. A hard core Yukawa model of fluid is studied with special attention to the critical region. To achieve this goal a formulation of the weighted density approximation coupled with the hierarchical reference theory, able to deal with critical long wavelength fluctuations, is put forward and compared with other approaches. The effective interaction between the walls is seen to change character on lowering the temperature: The strong oscillations induced by layering of the molecules, typical of the depletion mechanism in hard core systems, are gradually smoothed and, close to the critical point, a long range attractive tail emerges leading to a scaling form which agrees with the expectations based on the critical Casimir effect. Strong corrections to scaling are seen to affect the results up to very small reduced temperatures. By use of the Derjaguin approximation, this investigation has natural implications for the aggregation of colloidal particles in critical solvents
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Synthesis of 6,7-Dihydro-8-(4-methyl-1-piperazinyl)-[1]benzoxepino[4,5-c]quinoline as Potential 5-HT3 Receptor Ligand
No full textTwo synthetic routes to the achievement of the title compound are described. The [1]benzoxepino[4,5-c]quinoline nucleus was prepared by nucleophilic aromatic fluoride displacement-cyclization and functionalized with N-methylpiperazine moiety. Alternatively the oxepino ring closure is shifted as the final step. An oxepine ring cleavage occurred in compounds (9) and (3); a mechanistical interpretation is proposed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Synthesis of 6-(4-Methyl-1-piperazinyl)-7H-indeno[2,1-c]quinoline Derivatives as Potential 5-HT Receptor Ligands
No full textTwo synthetic pathways for the achievement of the title compounds are reported. The key intermediate, namely 3-carboxy-4-phenyl-2(1H)-quinolinone 9, was directly cyclized into the corresponding 6-chloro-7H-indeno[2,1-c]quinolin-7-one 10 or alternatively it was esterified, reduced to the alcohol, chlorinated and cyclized into the 6-chloro-7H-indeno[2,1-c]quinoline 8. Further reaction of the chloroindenoquinoline derivatives with N-methylpiperazine afforded the piperazinyl derivatives 4a-c
Fluid flow at interfaces driven by thermal gradients
No full textThermal forces drive several nonequilibrium phenomena able to set a fluid in motion without pressure gradi-ents. Although the most celebrated effect is thermophoresis, also known as Ludwig-Soret effect, probably the simplest example where thermal forces are at play is thermo-osmosis: The motion of a confined fluid exclusively due to the presence of a temperature gradient. We present a concise but complete derivation of the microscopic theory of thermo-osmosis based on linear response theory. This approach is applied to a simple fluid confined in a slab geometry, mimicking the flow through a pore in a membrane separating two fluid reservoirs at different temperatures. We consider both the case of an open channel, where the fluid can flow freely, and that of a closed channel, where mass transport is inhibited and a pressure drop sets in at the boundaries. Quantitative results require the evaluation of generalized transport coefficients, but a preliminary check on a specific prediction of the theory has been successfully performed via nonequilibrium molecular dynamics simulations
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