1,721,414 research outputs found
On the dynamic of the nonlinear reaction diffusion equation u_t=∆F(u)+f(x,u,∇u) under Robin boundary data
No full textLet Omega be a bounded smooth domain in R^3. Under Robin boundary data, the nonlinear
reaction diffusion equation
u_t=∆F(u)+f(x,u,∇u), (x, t) in Omega x R^+, is studied. Existence, uniqueness, stability and longtime behaviour of solutions are analyzed. An application
to the dynamic of a population inhabiting a strongly heterogeneous environment is considered
La longue durée del dopo terremoto in Irpinia. Esiti e questioni attuali di una ricostruzione post sisma, in Esposito D., Vitiello M. (a cura di), Il sisma e la guerra. Interventi di ricostruzione sulla città violata. Quadro storico, Edizioni Quasar, Roma 2021, pp. 123-137.
No full text
Physics and technology of Terahertz quantum cascade lasers
No full textEven though already in the seventies, right after the invention of the quantum cascade laser (QCL) concept, it was argued that this device could be operated in the THz (far-infrared) range of the electromagnetic spectrum, it was only in 2002 that the first working THz QCL was demonstrated. Soon afterwards, the progress was very rapid; in the space of 2–3 years, operating temperatures were raised, single-mode DFB devices were produced, applications as local oscillators in heterodyne transceivers were implemented, frequency coverage was extended to the whole 1–5 THz region. In the last few years, technological advancement has continued to improve performances: the maximum operating temperature has now reached about 250 K and about 1 W peak output power has been demonstrated. Several beam engineering techniques have been implemented, with the scope of enhancing spectral purity, improving beam quality and achieving vertical emission. In parallel, various approaches have been devised that allow frequency tunability of the emitted light, with the most efficient schemes achieving a tuning range of about 10% of the central emission frequency. Even the generation of frequency combs directly from THz QCLs has been obtained, by employing dispersion compensated waveguides and an intrinsic material non-linearity. This manuscript reviews the physics underlying the operation of THz QCLs, the technology developed to advance laser performances, and highlights the latest most promising progresses in this fascinating area of opto-electronics
A Kiss Is Just a Kiss, or Is It? A Comparative Look at Italian and American Sex Crimes
Full text linkL’inserimento lavorativo e l'imprenditoria di origine straniera
No full textNel primo rapporto a cura di Pugliese e Vitiello si è fatto ricorso ai dati disponibili allo scopo principale di dare conto dell’inserimento lavorativo degli immigrati connesso alla domanda di lavoro proveniente dalle imprese e dalle famiglie romane e alle iniziative di imprenditorialità etnica, di auto-promozione o auto-impiego degli stessi stranieri. Il materiale statistico utilizzato era funzionale a fornire un quadro di riferimento capace di mostrare la specificità dell’inserimento lavorativo nell’area romana e, nello stesso tempo, l’articolazione e la complessità delle situazioni, che le differenze per nazionalità e genere riescono a far emergere in modo chiaro, ancorché incompleto. In questo secondo rapporto, si è inteso certamente proporre un aggiornamento della situazione, ma appare di sicuro interesse un approfondimento sui limiti del quadro informativo attuale e sulle potenzialità delle fonti disponibili, con l’obiettivo di poter pervenire in futuro ad un effettivo monitoraggio dell’inserimento degli immigrati nel mercato del lavoro romano. La struttura del contributo è pertanto la seguente: 1. Un quadro informativo in rapida evoluzione 2. Tempo, spazio e genere 3. L'occupazione dipendente 3.1. Gli occupati regolari secondo i dati Inail 3.2. Un approfondimento sui lavoratori domestici (dati Inps) 4. L'imprenditoria di origine straniera 4.1. L'evoluzione del fenomeno 4.2. Le caratteristiche 5. Considerazioni conclusiv
On the nonlinear diffusion in the exterior of a sphere
No full textThe long time behaviour of the solutions of the equation u(t) = Delta F(u) in exterior domains is studied
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
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