Search results for "libri"

Temperature dependent mechanical unfolding of calixarene nanocapsules studied by molecular dynamics simulations.

2019

Using atomistic molecular dynamics simulations, we study the temperature dependence of the mechanical unfolding of a model supramolecular complex, a dimer of interlocked calixarene capsules. This system shows reversible transitions between two conformations that are stabilized by different networks of hydrogen bonds. We study the forced dissociation and formation of these networks as a function of temperature and find a strong impact of the nonequilibrium conditions imposed by pulling the system mechanically. The kinetics of the transition between the two conformations is ideally suited to investigate the range of validity of the stochastic models employed in the analysis of force dependent…

A TNF-α Promoter Polymorphism Is Associated with Juvenile Onset Psoriasis and Psoriatic Arthritis

1997

Tumor necrosis factor-α is considered to be one of the important mediators in the pathogenesis of psoriasis. A strong association of juvenile onset psoriasis with the major histocompatibility complex encoded HLA-Cw6 antigen has been reported but it is unclear whether Cw6 itself or a closely linked gene is involved in the pathogenesis. This study has focused on the association of promoter polymorphisms of the major histocompatibility complex encoded tumor necrosis factor-α gene with psoriasis and psoriatic arthritis. Tumor necrosis factor-α promoter polymorphisms were sought by sequence-specific oligonucleotide hybridization and by direct sequencing in Caucasian patients with juvenile onset …

Autobiografia(e) in forma d’archivio. Giovanna Brogna/Sonnino tra iconotestualit  e libri d’artista

2021

Il contributo prende in esame l’attivit  poliedrica di Giovanna Brogna/Sonnino proponendo un confronto tra le differenti aree di ricerca (fotografia, cinema, arti visive) esplorate dall’artista che ama sconfinare tra tecniche e linguaggi spesso incrociati tra loro. L’analisi del libro d’artista Lettere al Dott. B. 1979-1987 (2019), raccolta di lettere battute a macchina indirizzate allo psicanalista di Brogna Sonnino e accompagnate da materiale eterogeneo (cartoline, fotografie, collage, fotocopie), offre l’occasione per ripercorrerne gli esordi da cineasta e l’approdo alle arti visive e di individuare alcune consonanze importanti fra i suoi diversi campi di ricerca: l’archivio come pratica…

The Exponential Dichotomy under Discretization on General Approximation Scheme

2011

This paper is devoted to the numerical analysis of abstract parabolic problem 𝑢  ( 𝑡 ) = 𝐴 𝑢 ( 𝑡 ) ; 𝑢 ( 0 ) = 𝑢 0 , with hyperbolic generator 𝐴 . We are developing a general approach to establish a discrete dichotomy in a very general setting in case of discrete approximation in space and time. It is a well-known fact that the phase space in the neighborhood of the hyperbolic equilibrium can be split in a such way that the original initial value problem is reduced to initial value problems with exponential decaying solutions in opposite time direction. We use the theory of compact approximation principle and collectively condensing approximation to show that such a decomposition o…

Global exponential stability of delayed Markovian jump fuzzy cellular neural networks with generally incomplete transition probability

2014

The problem of global exponential stability in mean square of delayed Markovian jump fuzzy cellular neural networks (DMJFCNNs) with generally uncertain transition rates (GUTRs) is investigated in this paper. In this GUTR neural network model, each transition rate can be completely unknown or only its estimate value is known. This new uncertain model is more general than the existing ones. By constructing suitable Lyapunov functionals, several sufficient conditions on the exponential stability in mean square of its equilibrium solution are derived in terms of linear matrix inequalities (LMIs). Finally, a numerical example is presented to illustrate the effectiveness and efficiency of our res…

Analysis of a jet stream induced gravity wave associated with an observed ice cloud over Greenland

2004

International audience; A polar stratospheric ice cloud (PSC type II) was observed by airborne lidar above Greenland on 14 January 2000. It was the unique observation of an ice cloud over Greenland during the SOLVE/THESEO 2000 campaign. Mesoscale simulations with the hydrostatic HRM model are presented which, in contrast to global analyses, are capable to produce a vertically propagating gravity wave that induces the low temperatures at the level of the PSC afforded for the ice formation. The simulated minimum temperature is ~8 K below the driving analyses and ~4.5 K below the frost point, exactly coinciding with the location of the observed ice cloud. Despite the high elevations of the Gre…

Lagrangian simulations of stable isotopes in water vapor: An evaluation of nonequilibrium fractionation in the Craig-Gordon model

2009

[1] The Craig-Gordon model is the basis for the parameterization of water isotope fractionation during evaporation from the ocean in many atmospheric isotope models. Its exact formulation (e.g., with respect to the nonequilibrium fractionation factor k) is mainly based on theoretical considerations and not very well constrained by observations. This study addresses this issue by combining a recently developed Lagrangian moisture source analysis with a Craig-Gordon fractionation parameterization for the identified evaporation events in order to model isotope ratios in water vapor. This technique is applied to 45 measurement days of isotopes in water vapor at Rehovot (Israel) during the years…

2008

Abstract. Sulfur isotope analysis of atmospheric aerosols is a well established tool for identifying sources of sulfur in the atmosphere, estimating emission factors, and tracing the spread of sulfur from anthropogenic sources through ecosystems. Conventional gas mass spectrometry averages the isotopic compositions of several different types of sulfur aerosol particles, and therefore masks the individual isotopic signatures. In contrast, the new single particle technique presented here determines the isotopic signature of the individual particles. Primary aerosol particles retain the original isotopic signature of their source. The isotopic composition of secondary sulfates depends on the i…

A reexamination of the equilibrium conditions in the theory of water drop nucleation

1975

The thermodynamic equations necessary to describe the conditions for equilibrium between a highly curved surface of a liquid and its vapour are re-examined. The complete equilibrium behaviour is reduced to one single differential equation for each component in an arbitrary c -component system. It is shown that this general formulation can be specialized to describe the conditions for equilibrium between water vapour and a pure water drop, the drop carrying an electric charge, containing a water soluble substance and/or containing a water insoluble nucleus. In the light of the present formulation, some incorrect physical statements of treatments by various authors reported in literature are …

Reactive halogen chemistry in volcanic plumes

2007

[1] Bromine monoxide (BrO) and sulphur dioxide (SO2) abundances as a function of the distance from the source were measured by ground-based scattered light Multiaxis Differential Optical Absorption Spectroscopy (MAX-DOAS) in the volcanic plumes of Mt. Etna on Sicily, Italy, in August–October 2004 and May 2005 and Villarica in Chile in November 2004. BrO and SO2 spatial distributions in a cross section of Mt. Etna's plume were also determined by Imaging DOAS. We observed an increase in the BrO/SO2 ratio in the plume from below the detection limit near the vent to about 4.5 × 10−4 at 19 km (Mt. Etna) and to about 1.3 × 10−4 at 3 km (Villarica) distance, respectively. Additional attempts were …