435 research outputs found
Confronto fra valutazioni del run-up fatte con un modello matematico e una formula empirica con misure di campo
La posizione planimetrica della linea di riva, soli
tamente, viene determinata
attraverso l\u2019uso di immagini aeree ed utilizzata pe
r la ricostruzione dell\u2019evoluzione
storica dei litorali. Tuttavia, le informazioni est
ratte da tali immagini, descrivendo il
confine istantaneo acqua-terra, consentono l\u2019indivi
duazione della linea di riva
esclusivamente come limite asciutto-bagnato proprio
nel momento della ripresa. Per
una pi\uf9 corretta localizzazione della linea di riva
, \ue8 quindi necessario quantificare,
oltre agli effetti di marea e di trasporto solido,
gli effetti prodotti dal moto ondoso
su tale posizione e in particolare il cosiddetto ru
n-up.
Nel presente lavoro si studia il run-up in una spia
ggia naturale a debole pendenza
ricadente nella Sicilia occidentale. Lo studio geom
orfologico del sito precede lo
studio idraulico, che partendo dalle misure di onde
al largo, attraverso la loro
trasposizione e la propagazione simulata con un mod
ello matematico, porta alla
stima delle onde sotto costa. Queste ultime sono ut
ilizzate per valutare il run-up sia
mediante una nota formula empirica sia utilizzando
un modello numerico alla
Boussinesq con una nuova condizione al contorno per
la linea di riva. Il confronto
dei risultati con le misure di campo mostra che i r
isultati migliori si ottengono con
la formula empirica, nella quale \ue8 tuttavia necessa
rio calibrare i coefficienti con
misure in situ
Zaltoprofen/4,4′-Bipyridine: A Case Study to Demonstrate the Potential of Differential Scanning Calorimetry (DSC) in the Pharmaceutical Field
The Zaltoprofen/4,4′-Bipyridine system gives rise to two co-crystals of different compositions both endowed - in water and in buffer solution at pH 4.5 - with considerably higher solubility and dissolution rate than the pure drug. The qualitative and quantitative analysis of the DSC measurements, carried out on samples made up of mixtures prepared according to different methodologies, allows us to elaborate and propose an accurate thermodynamic model that fully takes into account the qualitative aspects of the complex experimental framework and which provides quantitative predictions (reaction enthalpies and compositions of the co-crystals) in excellent agreement with the experimental results. Co-crystal formation and cocrystal compositions were confirmed by X-ray diffraction measurements as well as by FT-IR and NMR spectroscopy measurements. The quantitative processing of DSC measurements rationalizes and deepens the scientific aspects underlying the so-called Tammann's triangle and constitutes a model of general validity. The work shows that DSC has enormous potential, which however can be fully exploited only by paying adequate attention to the experimental aspects and the quantitative processing of the measurements
Ventilazione selettiva mediante tubo Sher-I-Bronc modificato in un caso di fistole broncopleurica
Complexity without chaos: Plasticity within random recurrent networks generates robust timing and motor control
It is widely accepted that the complex dynamics characteristic of recurrent
neural circuits contributes in a fundamental manner to brain function. Progress
has been slow in understanding and exploiting the computational power of
recurrent dynamics for two main reasons: nonlinear recurrent networks often
exhibit chaotic behavior and most known learning rules do not work in robust
fashion in recurrent networks. Here we address both these problems by
demonstrating how random recurrent networks (RRN) that initially exhibit
chaotic dynamics can be tuned through a supervised learning rule to generate
locally stable neural patterns of activity that are both complex and robust to
noise. The outcome is a novel neural network regime that exhibits both
transiently stable and chaotic trajectories. We further show that the recurrent
learning rule dramatically increases the ability of RRNs to generate complex
spatiotemporal motor patterns, and accounts for recent experimental data
showing a decrease in neural variability in response to stimulus onset
Genome wide analysis of gene expression changes in skin from patients with type 2 diabetes
Non-healing chronic ulcers are a serious complication of diabetes and are a major healthcare problem. While a host of treatments have been explored to heal or prevent these ulcers from forming, these treatments have not been found to be consistently effective in clinical trials. An understanding of the changes in gene expression in the skin of diabetic patients may provide insight into the processes and mechanisms that precede the formation of non-healing ulcers. In this study, we investigated genome wide changes in gene expression in skin between patients with type 2 diabetes and non-diabetic patients using next generation sequencing. We compared the gene expression in skin samples taken from 27 patients (13 with type 2 diabetes and 14 non-diabetic). This information may be useful in identifying the causal factors and potential therapeutic targets for the prevention and treatment of diabetic related diseases
Maintaining extensivity in evolutionary multiplex networks
In this paper, we explore the role of network topology on maintaining the extensive property of entropy. We study analytically and numerically how the topology contributes to maintaining extensivity of entropy in multiplex networks, i.e. networks of subnetworks (layers), by means of the sum of the positive Lyapunov exponents, HKS, a quantity related to entropy. We show that extensivity relies not only on the interplay between the coupling strengths of the dynamics associated to the intra (short-range) and inter (long-range) interactions, but also on the sum of the intra-degrees of the nodes of the layers. For the analytically treated networks of size N, among several other results, we show that if the sum of the intra-degrees (and the sum of inter-degrees) scales as N?+1, ? > 0, extensivity can be maintained if the intra-coupling (and the inter-coupling) strength scales as N??, when evolution is driven by the maximisation of HKS. We then verify our analytical results by performing numerical simulations in multiplex networks formed by electrically and chemically coupled neurons
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