Search results for "Sima"
showing 10 items of 248 documents
Protoplanetary Disks, Solar System Minor Bodies and Origin of Life
2001
In the last decade, planetary science researchers have obtained significant advances on the origin and evolution of life on Earth. The increasing resolution and the development of new instruments (as space telescopes and adaptative optics) has provided first detailed images on protoplanetary disks and star formation regions. Moreover, in the last few years, doppler spectroscopic technique has confirmed the presence of extrasolar planets. These evidence shows planetary formation as a continuous and very common process in the Cosmos, indicating that our Solar System is not too special as was suggested in the past.
Bounding principles for elastic-plastic-creeping solids loaded below and above the shakedown limit
1982
Solids of elastic-perfectly plastic creeping material subjected to variable loads are considered within the infinitesimal displacement framework and a bounding principle is presented which holds below and above the shakedown limit. Through the choice of some free parameters, this principle generates a number of deformation bounds with practical meanings, some of wich coincide with known results for creeping and noncreeping material, while others constitute new results or generalizations of known results. The topic will be further studied in a subsequent paper [35].
Organotin(IV) derivatives with 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidine and their cytotoxic activities: The importance of being conformers
2014
Abstract The organotin(IV) compounds Me2SnCl2(dbtp)(1), Me2SnCl2(dbtp)2 (2), Et2SnCl2(dbtp) (3), Et2SnCl2(dbtp)2 (4), Et2SnCl2(dptp) (5), nBu2SnCl2(dbtp)2 (6), nBu2SnCl2(dptp) (7), Ph2SnCl2(dbtp) (8), Ph2SnCl2(EtOH)2(dptp)2 (9), where dbtp = 5,7-di-tert-butyl-1,2,4-triazolo[1,5-a]pyrimidine and dptp = 5,7-diphenyl-1,2,4-triazolo [1,5-a]pyrimidine, have been tested by MTT for their cytotoxic activity on three tumor cell lines, HepG2 (human hepatocellular carcinoma), HeLa (human cervix adenocarcinoma) and MCF-7 (human breast cancer). Except for 1 and 2, which were ineffective, all compounds significantly showed a dose-dependent anti-proliferative effect against the three cell lines. By calcul…
Lo spirito celato nel desiderio. Riflessioni per una fenomenologia ed un'ermeneutica metafisica della persona
2020
L’analitica esistenziale evidenzia come ogni persona che viene a questo mondo non sceglie l’essere e non sceglie la forma della sua esistenza; ogni persona è definita da un limite originario per la sua libertà, un’insuperabile finitezza. Inoltre - fatto massimamente ovvio, ma sorprendentemente suggestivo di senso - ogni persona che viene a questo mondo, nasce piccolo/piccola e il tempo dell’esistenza è un continuo, possibile, processo di crescita personale. Proprio dai mondi dell’educazione apprendiamo questa verità semplice: con evidenza emerge che la persona non è ma diviene se stessa; quasi debba colmare una mancanza costitutiva percepita come intollerabile, essa appare segnata da una te…
Changes in yield ofin-vivo fluorescence of chlorophyll a as a tool for selective herbicide monitoring
1993
Triazines and derivatives of phenylurea, which are often found in outdoor water samples, induce specific changes in the yield of thein-vivo chlorophyll α-fluorescence of PSII. These changes are correlated quantitatively with the concentration of the herbicides and can therefore be used to set-up a low-price monitor system. In order to detect selectively the herbicide-sensitive part of the fluorescence emission a pulse amplitude modulated fluorimeter was used. The bioassay system was optimised with respect to test organism, growing and measuring conditions. The relationship between fluorescence yield and herbicide concentrations were experimentally determined for the triazines atrazine and s…
Une historicitation (quasi)radicale : sens des études classiques et approche méthodologique chez Diego Lanza
2013
Lo studio costituisce un capitolo di storia degli studi di filologia e cultura greca incentrata sull’analisi dell’opera di Diego Lanza. Si rintracciano all’interno di questa le parole chiave che costituiscono il senso del lavoro dello studioso (conflitto, contraddizione, tensioni, ideologie, mediazioni, istituzioni) improntato all’indagine di carattere sociologico e si mette in luce il rapporto di tale lavoro con il contesto politico e culturale degli anni in cui il pensiero di Lanza si è formato e sviluppato. L’approccio dello studioso, fortemente consapevole sul piano teorico, evita l’applicazione di un “metodo astratto” e privilegia invece l’analisi concreta dei testi - degli scarti e de…
Approximating the solutions of differential inclusions driven by measures
2019
The matter of approximating the solutions of a differential problem driven by a rough measure by solutions of similar problems driven by “smoother” measures is considered under very general assumptions on the multifunction on the right-hand side. The key tool in our investigation is the notion of uniformly bounded $$\varepsilon $$-variations, which mixes the supremum norm with the uniformly bounded variation condition. Several examples to motivate the generality of our outcomes are included.
Low-pressure ferroelastic phase transition in rutile-type AX2 minerals: cassiterite (SnO2), pyrolusite (MnO2) and sellaite (MgF2)
2019
The structural behaviour of cassiterite (SnO2), pyrolusite (MnO2) and sellaite (MgF2), i.e. AX2-minerals, has been investigated at room temperature by in situ high-pressure single-crystal diffraction, up to 14 GPa, using a diamond anvil cell. Such minerals undergo a ferroelastic phase transition, from rutile-like structure (SG: P42/mnm) to CaCl2-like structure (SG: Pnnm), at ≈ 10.25, 4.05 and 4.80 GPa, respectively. The structural evolution under pressure has been described by the trends of some structure parameters that are other than zero in the region of the low-symmetry phase’s stability. In particular, three tilting-angles (ω, ω′, ABS) and the metric distortion of the cation-centred oc…
New Results on Identifiability of Nonlinear Systems
2004
Abstract In this paper, we recall definition of identifiability of nonlinear systems. We prove equivalence between identifiability and smooth identifiability. This new result justifies our definition of identifiability. In a previous paper (Busvelle and Gauthier, 2003), we have established that • If the number of observations is three or more, then, systems are generically identifiable. • If the number of observations is 1 or 2, then the situation is reversed. Identifiability is not at all generic. Also, we have completely classified infinitesimally identifiable systems in the second case, and in particular, we gave normal forms for identifiable systems. Here, we will give similar results i…
Modulus of continuity with respect to semigroups of analytic functions and applications
2016
Abstract Given a complex Banach space E , a semigroup of analytic functions ( φ t ) and an analytic function F : D → E we introduce the modulus w φ ( F , t ) = sup | z | 1 ‖ F ( φ t ( z ) ) − F ( z ) ‖ . We show that if 0 α ≤ 1 and F belongs to the vector-valued disc algebra A ( D , E ) , the Lipschitz condition M ∞ ( F ′ , r ) = O ( ( 1 − r ) 1 − α ) as r → 1 is equivalent to w φ ( F , t ) = O ( t α ) as t → 0 for any semigroup of analytic functions ( φ t ) , with φ t ( 0 ) = 0 and infinitesimal generator G , satisfying that φ t ′ and G belong to H ∞ ( D ) with sup 0 ≤ t ≤ 1 ‖ φ ′ ‖ ∞ ∞ , and in particular is equivalent to the condition ‖ F − F r ‖ A ( D , E ) = O ( ( 1 − r ) α ) as r …