Search results for "Concert"
showing 10 items of 67 documents
The link between independent acquisition of intracellular gamma-endosymbionts and concerted evolution in Tremblaya princeps
2015
Many insect species establish mutualistic symbiosis with intracellular bacteria that complement their unbalanced diets. The betaproteobacterium "Candidatus Tremblaya" maintains an ancient symbiosis with mealybugs (Hemiptera: Pseudococcidae), which are classified in subfamilies Phenacoccinae and Pseudococcinae. Most Phenacoccinae mealybugs have "Candidatus Tremblaya phenacola" as their unique endosymbiont, while most Pseudococcinae mealybugs show a nested symbiosis (a bacterial symbiont placed inside another one) where every "Candidatus Tremblaya princeps" cell harbors several cells of a gammaproteobacterium. Genomic characterization of the endosymbiotic consortium from Planococcus citri, co…
Nuclear rDNA pseudogenes in Chagas disease vectors: Evolutionary implications of a new 5.8S+ITS-2 paralogous sequence marker in triatomines of North,…
2013
A pseudogene, paralogous to rDNA 5.8S and ITS-2, is described in Meccus dimidiata dimidiata, M. d. capitata, M. d. maculippenis, M. d. hegneri, M. sp. aff. dimidiata, M. p. phyllosoma, M. p. longipennis, M. p. pallidipennis, M. p. picturata, M. p. mazzottii, Triatoma mexicana, Triatoma nitida and Triatoma sanguisuga, covering North America, Central America and northern South America. Such a nuclear rDNA pseudogene is very rare. In the 5.8S gene, criteria for pseudogene identification included length variability, lower GC content, mutations regarding the functional uniform sequence, and relatively high base substitutions in evolutionary conserved sites. At ITS-2 level, criteria were the shor…
Z dziejów muzyki kościelnej w Międzylesiu na ziemi kłodzkiej
2014
A DFT study of the role of Lewis acid catalysts in the mechanism of the 1,3-dipolar cycloaddition of nitrile imines towards electron-deficient acrylo…
2012
Abstract The role of the Mg complex formation in the reaction rate and regioselectivity of the 1,3-dipolar cycloaddition (13DC) reactions of nitrile imines (NIs) towards electron-deficient methacryloylpyrazolidinones has been theoretically studied using DFT methods at the B3LYP/6-31G * level. These 13DC reactions have an asynchronous concerted mechanism with a low polar character, displaying a high C regioselectivity induced by a steric repulsion between the phenyl substituent present at the C3 carbon of the NIs and the pyrazolidinone appendage present in the methacryloyl derivative, which increases with the formation of the bulky Mg–methacryloylpyrazolidinone complex. Solvent effect has be…
Sequence features and evolutionary mechanisms in the chicken avidin gene family
2001
The chicken avidin gene family comprises the avidin gene (avd) and several homologous avidin-related genes (avrs). The sequences of the avr genes are nearly identical to each other but exhibit nonrandomly distributed, frequently nonsynonymous nucleotide substitutions compared to avd. In this study, we determined the genetic distances and the phylogeny of the avd and avr genes and found differences between different exons and introns. Our results suggest the involvement of biased gene conversion in the evolution of the genes. Furthermore, one of the genes was identified as a putative fusion gene. The occurrence of both gene conversion and recombination supports the models suggesting a common…
El tiempo un modo de orden. Una paradoja en la historia como disciplina escolar
2012
Se analiza la contraposición entre duración y medición en la paradoja del tiempo de la Civilización Occidental. A la luz de los planteamientos de Henri Bergson (la duración entendida como flujo) y Galileo, Descartes y Newton (la medición como orden científico y el tiempo medido). El estudio de duración y medición, permite transformar la paradoja del tiempo en un dispositivo, para indagar en el orden escolar. La pregunta principal es, ¿Qué significados sobre el orden escolar y su disciplina permite construir la paradoja del tiempo, concebida como un dispositivo, en la historia como asignatura escolar? Bajo la premisa: El dispositivo de la paradoja del tiempo en la historia como asignatura es…
Understanding the mechanism of non-polar diels-alder reactions. A comparative elf analysis of concerted and stepwise diradical mechanisms
2010
The electron-reorganization along the concerted and stepwise pathways associated with the non-polar Diels-Alder reaction between cyclopentadiene (Cp, 1) and ethylene (2) has been studied using the topological analysis of the electron localization function (ELF) at the B3LYP/6-31G(d) level of theory. ELF results for the concerted mechanism stresses that the electron-reorganization demanded on the diene and ethylene reagents to reach two pseudo-diradical structures is responsible for the high activation energy. A comparative ELF analysis of some relevant points of the non-polar Diels-Alder reaction between Cp and styrene (10) suggests that these concerted mechanisms do not have a pericyclic e…
Une élève napolitaine: Luisa Cognetti (1857-1952)
2011
Nata a Napoli il 20 luglio 1857 in una famiglia della buona borghesia, Luisa Cognetti crebbe in un ambiente culturalmente stimolante: il padre Salvatore fu avvocato e giornalista, il fratello Goffredo un commediografo di qualche successo. Nel novembre 1876 cominciò a frequentare le lezioni di Liszt a Roma e il 23 gennaio 1877 diede il suo primo concerto, iniziando una carriera che la porterà ad esibirsi in quasi tutta l’Europa. Il matrimonio con Carlo Michon nel 1891 segna l’abbandono dell’attività concertistica. Solamente alla morte del marito, nel 1921, si dedica per qualche tempo all’insegnamento. Muore a Livorno il 7 luglio 1952. Dei suoi rapporti con Liszt e della sua attività concerti…
Cognetti, Luisa, verh. Michon
2011
Si ricostruisce l'attività concertistica in Italia e all'estero della pianista napoletana Luisa Cognetti (1857-1952), allieva di Franz Liszt.
Évaluation, concertation, et processus de décision
2003
The author outlines the theoretical and sociological considerations influencing the decision-making cycle for the French education ministry. He makes the case that education policy has been guided by ideological and political considerations rather than by scientific evidence and evaluation-based processes. He calls for widespread use of external appraisals involving the concerned actors.