Search results for "Coupling"
showing 10 items of 1862 documents
Violation of the equivalence principle from light scalar dark matter
2018
In this paper, we study the local observational consequences of a violation of the Einstein Equivalence Principle induced by models of light scalar Dark Matter (DM). We focus on two different models where the scalar field couples linearly or quadratically to the standard model of matter fields. For both these cases, we derive the solutions of the scalar field. We also derive from first principles the expressions for two types of observables: (i) the local comparison of two atomic sensors that are differently sensitive to the constants of Nature and (ii) the local differential acceleration between two test-masses with different compositions. For the linear coupling, we recover that the signa…
A universal definition of life: autonomy and open-ended evolution.
2004
Life is a complex phenomenon that not only requires individual self-producing and self- sustaining systems but also a historical-collective organization of those individual systems, which brings about characteristic evolutionary dynamics. On these lines, we propose to define univer- sally living beings as autonomous systems with open-ended evolution capacities, and we claim that all such systems must have a semi-permeable active boundary (membrane), an energy trans- duction apparatus (set of energy currencies) and, at least, two types of functionally interdependent macromolecular components (catalysts and records). The latter is required to articulate a 'phenotype- genotype' decoupling that…
MAGEMin 1.0.0
2022
MAGEMin is a Gibbs energy minimization solver package, which computes the thermodynamically most stable assemblage for a given bulk rock composition and pressure/temperature condition. It also returns parameters such as melt fraction or density, which can be combined with geodynamic/petrological tools to simulate, for example, the evolving chemistry of a crystallising melt. MAGEMin is written as a parallel C library and uses a combination of linear programming, extended Partitioning Gibbs free Energy and gradient-based local minimization to compute the most stable mineral assemblage. In this, it differs from exisisting approaches which makes it particularly suitable to utilize modern multic…
MAGEMin 1.0.0
2022
MAGEMin is a Gibbs energy minimization solver package, which computes the thermodynamically most stable assemblage for a given bulk rock composition and pressure/temperature condition. It also returns parameters such as melt fraction or density, which can be combined with geodynamic/petrological tools to simulate, for example, the evolving chemistry of a crystallising melt. MAGEMin is written as a parallel C library and uses a combination of linear programming, extended Partitioning Gibbs free Energy and gradient-based local minimization to compute the most stable mineral assemblage. In this, it differs from exisisting approaches which makes it particularly suitable to utilize modern multic…
Le débat macroévolutif : apports de la disparité morphologique
2003
Resume La theorie macroevolutive est abordee sous des aspects historiques, puis sous un de ses aspects plus novateurs, qui aboutit a l’elaboration d’un programme de recherche initie par differentes equipes depuis une dizaine d’annees : il consiste a decoupler les composantes taxinomiques (diversite) et morphologiques (disparite) de la biodiversite, lors de l’etude de ses fluctuations. Plusieurs etudes suggerent des decouplages temporels frequents entre ces deux metriques au cours de l’histoire des clades. La confrontation des deux apparait comme une demarche feconde qui a permis d’explorer en termes de patterns , mais egalement de processus, les fluctuations de la biodiversite a large echel…
SYSTEMS DECOMPOSITION AND COUPLING
1993
In order to handle efficiently complex models of real systems, it is a convenient practice to decompose them into subsystems that are validated independently. The next step would be joining the subsystems into a global system and performing a new global validation. A formalization of this process is performed as a consequence of practical experience with a model generator expert system based on general systems theory.
Local dynamic properties of the heme pocket in native and solvent-induced molten-globule-like states of cytochrome c
2002
We report the Soret absorption band, down to cryogenic temperature, of native and molten-globule-like state of horse heart cytochrome c. The band profile is analyzed in terms of vibronic coupling of the heme normal modes to the electronic transition in the framework of the Franck-Condon approximation. From the temperature dependence of the Gaussian broadening and of the peak position, we obtain information on the 'bath' of low frequency harmonic motions of the heme group within the heme pocket. The reported data indicate that, compared to the native state, the less rigid tertiary structure of the molten globule is reflected in a higher flexibility of the heme pocket and in greater conformat…
DEEP EUTECTIC SOLVENTS E LIQUIDI IONICI: SOLVENTI PER LO SVILUPPO DI PROCESSI ECO-COMPATIBILI
2020
L’obiettivo di questi tre anni di Dottorato è stato lo studio e l’utilizzo nuovi solventi di reazione in grado di sostituire i solventi organici classici. In particolare sono stati studiati i Deep Eutectic Solvent (DES) e le miscele di Liquidi Ionici (IL). I DES sono stati utilizzati come solventi per lo studio di reazioni organiche, usate per la formazione di nuovi legami C-C. Nello specifico sono state studiate la reazione di Diels-Alder, e diverse reazioni di coupling C-C catalizzate da Pd. In seguito, i DES sono stati utilizzati per la formazione di nuovi gel supramolecolari, chiamati eutectogel. Questi gel sono stati formati usando come gelator amminoacidi naturali, consentendo quindi …
Synthesis of Highly Functionalized N , N ‐Diarylamides by an Anodic C, N ‐Coupling Reaction
2019
We report an innovative, sustainable and straightforward protocol for the synthesis of N,N-diarylamides equipped with nonprotected hydroxyl groups by using electrosynthesis. The concept allows the application of various substrates furnishing diarylamides with yields up to 57 % within a single and direct electrolytic protocol. The method is thereby easy to conduct in an undivided cell with constant current conditions offering a versatile and short-cut alternative to conventional pathways.
A Bipyridine‐Palladium Derivative as General Pre‐Catalyst for Cross‐Coupling Reactions in Deep Eutectic Solvents
2019
A versatile and DES‐compatible bipyridine palladium complex has been developed as a general pre‐catalyst for different cross‐coupling reactions (Hiyama, Suzuki‐Miyaura, Heck‐Mizoroki and Sonogashira) in deep eutectic solvents. Hydrogen bond capacity of the ligand allows to keep the excellent level of results previously obtained in classical organic solvents. Palladium pre‐catalyst showed a high catalytic activity for many cross‐coupling reactions, demonstrating a great versatility and applicability. Also, this methodology employs sustainable solvents as a reaction medium and highlights the potential of DES as alternative solvents in organometallic catalysis. The catalyst and DES were easily…