Understorey phylogenetic diversity in thermophilous deciduous forests : overstorey species identity can matter more than species richness

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École(s) de Paris : enquête sur les compositeurs étrangers à Paris dans l'entre-deux-guerres

Thèse soutenue le 27 février 2015 devant un jury composé par Marie-Hélène Benoit-Otis (présidente, Université de Montréal), François de Médicis (Université de Montréal), Christopher Moore (Université d'Ottawa) et Michel Duchesneau (Université de Montréal).« École de Paris » est une expression souvent utilisée pour désigner un groupe de compositeurs étrangers ayant résidé à Paris dans l’entre-deux-guerres. Toutefois, « École de Paris » dénomme des réalités différentes selon les sources. Dans un sens élargi, le terme comprend tous les compositeurs de toute époque ayant vécu au moins une partie de leur vie à Paris. Dans son sens le plus strict, il désigne le prétendu regroupement de quatre à six compositeurs arrivés à Paris dans les années 1920 et comprenant notamment Conrad Beck, Tibor Harsányi, Bohuslav Martinů, Marcel Mihalovici, Alexandre Tansman et Alexandre Tchérepnine. Dans le but de revisiter l’histoire de l’utilisation de cette expression, nous avons reconstitué le discours complexe et contradictoire à propos de la question « qu’est-ce que l’École de Paris? ». Notre « enquête », qui s’est déroulée à travers des documents historiques de l’entre-deux-guerres ainsi que des textes historiographiques et de vulgarisation parus jusqu’à nos jours, nous a mené à la conclusion que l’École de Paris est un phénomène discursif que chaque acteur a pu manipuler à sa guise, car aucun fait ne justifie une utilisation univoque de cette expression dans le milieu musical parisien des années 1920-1930. L’étude de la programmation musicale nous a permis notamment de démontrer qu’aucun évènement regroupant les compositeurs considérés comme des « membres » de l’École de Paris n’a jamais eu lieu entre 1920 et 1940. Par la suite, nous avons contextualisé ce discours pour comprendre quels faits et quelle rhétorique dominante l’ont rendu possible. L’expression utilisée en musique est une extension de celle introduite dans le milieu des arts visuels dans les années 1920, dictée par la tendance dominante dans le Paris cosmopolite à marquer une distinction nette entre les Français et les étrangers. Nous avons à ce propos approfondi les différentes formes de nationalisme musical, et leur rôle dans la création d’un discours faisant de l’École de Paris une question stylistique – une position qui affirme l’existence d’un « style École de Paris » distinct de la « musique française ». En plus des reconstitutions du discours des tiers et du contexte, nous avons interrogé les discours tenus par les compositeurs concernés. L’étude de plusieurs documents inédits nous apprend que ces compositeurs s’opposent fermement, dans l’entre-deux-guerres, aux tentatives de les considérer comme un groupe. Mais qu’après la Seconde Guerre mondiale, ils épousent le discours favorable à l’image homogène et cohérente d’une École de Paris, contribuant ainsi à sa fortune historiographique.“School of Paris” (École de Paris) is a term often used to indicate a group of foreign composers who resided in Paris in the years between World War I and II. However, depending on the source, “School of Paris” can have various meanings. In a broader sense, it includes all composers in any era who lived at least part of their lives in Paris. In its strictest sense, it refers to the alleged group of four to six composers who arrived in Paris in the 1920s: Conrad Beck, Tibor Harsányi, Bohuslav Martinů, Marcel Mihalovici, Alexandre Tansman, and Alexander Tcherepnin. In order to revisit the history of the use of this term, we have reconstructed the complex and contradictory discourse concerning the question: “what is the School of Paris?”. Our “investigation”, which took place through historical documents of the interwar years, as well as historiographical and popularized texts published up to today, led us to the conclusion that the School of Paris is a discursive phenomenon that each performer could manipulate at will, since no factual evidence justifies an unequivocal use of this term in the Parisian musical milieu of the 1920s and 1930s. Most notably, the study of musical programming allowed us to demonstrate that no particular event or gathering of the so-called “members” of the School of Paris ever took place between 1920 and 1940. Subsequently, we have contextualized this discourse to understand which facts and which prominent rhetoric made it possible. The term used in music is an extension of that which was introduced in the milieu of visual arts in the 1920s, dictated by the dominant tendency in cosmopolitan Paris to make a clear distinction between the French and the non-French. In this light, we have thoroughly examined the different forms of musical nationalism and their role in creating a discourse on the School of Paris as a question of style — a position that asserts the existence of a “School of Paris style”, distinct from that of “French music”. In addition to the reconstructions of third party and contextualized discourse, we have examined the discourses held by the composers in question. The study of several unpublished documents shows us that these composers were strongly opposed, during the interwar years, to attempts to treat them as a group. Not until after the Second World War do they couple this discourse with the favourable image of a homogeneous and coherent School of Paris, thus contributing to its historiographical fortune

Brain stimulation as a therapeutic tool in Amyotrophic Lateral Sclerosis: current status and interaction with mechanisms of altered cortical excitability

In the last 20 years, several modalities of neuromodulation, mainly based on non-invasive brain stimulation (NIBS) techniques, have been tested as a non-pharmacological therapeutic approach to slow disease progression in amyotrophic lateral sclerosis (ALS). In both sporadic and familial ALS cases, neurophysiological studies point to motor cortical hyperexcitability as a possible priming factor in neurodegeneration, likely related to dysfunction of both excitatory and inhibitory mechanisms. A trans-synaptic anterograde mechanism of excitotoxicity is thus postulated, causing upper and lower motor neuron degeneration. Specifically, motor neuron hyperexcitability and hyperactivity are attributed to intrinsic cell abnormalities related to altered ion homeostasis and to impaired glutamate and gamma aminobutyric acid gamma-aminobutyric acid (GABA) signaling. Several neuropathological mechanisms support excitatory and synaptic dysfunction in ALS; additionally, hyperexcitability seems to drive DNA-binding protein 43-kDA (TDP-43) pathology, through the upregulation of unusual isoforms directly contributing to ASL pathophysiology. Corticospinal excitability can be suppressed or enhanced using NIBS techniques, namely, repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), as well as invasive brain and spinal stimulation. Experimental evidence supports the hypothesis that the after-effects of NIBS are mediated by long-term potentiation (LTP)-/long-term depression (LTD)-like mechanisms of modulation of synaptic activity, with different biological and physiological mechanisms underlying the effects of tDCS and rTMS and, possibly, of different rTMS protocols. This potential has led to several small trials testing different stimulation interventions to antagonize excitotoxicity in ALS. Overall, these studies suggest a possible efficacy of neuromodulation in determining a slight reduction of disease progression, related to the type, duration, and frequency of treatment, but current evidence remains preliminary. Main limitations are the small number and heterogeneity of recruited patients, the limited "dosage" of brain stimulation that can be delivered in the hospital setting, the lack of a sufficient knowledge on the excitatory and inhibitory mechanisms targeted by specific stimulation interventions, and the persistent uncertainty on the key pathophysiological processes leading to motor neuron loss. The present review article provides an update on the state of the art of neuromodulation in ALS and a critical appraisal of the rationale for the application/optimization of brain stimulation interventions, in the light of their interaction with ALS pathophysiological mechanisms

Neurobiological After-Effects of Low Intensity Transcranial Electric Stimulation of the Human Nervous System: From Basic Mechanisms to Metaplasticity

Non-invasive low-intensity transcranial electrical stimulation (tES) of the brain is an evolving field that has brought remarkable attention in the past few decades for its ability to directly modulate specific brain functions. Neurobiological after-effects of tES seems to be related to changes in neuronal and synaptic excitability and plasticity, however mechanisms are still far from being elucidated. We aim to review recent results from in vitro and in vivo studies that highlight molecular and cellular mechanisms of transcranial direct (tDCS) and alternating (tACS) current stimulation. Changes in membrane potential and neural synchronization explain the ongoing and short-lasting effects of tES, while changes induced in existing proteins and new protein synthesis is required for long-lasting plastic changes (LTP/LTD). Glial cells, for decades supporting elements, are now considered constitutive part of the synapse and might contribute to the mechanisms of synaptic plasticity. This review brings into focus the neurobiological mechanisms and after-effects of tDCS and tACS from in vitro and in vivo studies, in both animals and humans, highlighting possible pathways for the development of targeted therapeutic applications

A proposito di Marrou, Agostino e la musica

Dal Traité de la musique selon l'esprit de Saint Augustin (1942) di H.-I. Marrou emerge la relazione tra la musica francese degli anni Trenta e il pensiero non-conformista. L’accento posto sul momento fruitivo della musica e in particolare sul suo fine etico si riallaccia ai propositi della rivoluzione spirituale che informa il cosiddetto spirito del 1930 e il manifesto della Jeune France: leggere il Traité può essere utile per affrontare le poetiche musicali umaniste degli anni Trenta, e al contempo il contesto storico spiega e giustifica il pensiero di Marrou, che può apparire altrimenti poco interessante.Quest'ultimo viene infatti sviluppato sulla scia del platonismo cristiano mediato da Agostino, che viene sottoposto a una serie di piccoli mutamenti in funzione di una migliore e più attuale teologia morale. L'esito filosofico non è tuttavia dei più convincenti, vuoi per i numerosi appelli al principio d'autorità, vuoi per le frequenti contraddizioni argomentative che emergono dal testo in modo evidente. La tensione tra la fedeltà alla dottrina, il tentativo di rilettura della musica in chiave apologetica e la proposta di una filosofia pratica producono così un vistoso scacco metodologico che rappresenta uno dei limiti maggiori del Trattato. Le considerazioni di Marrou sul rapporto tra cristianesimo e filosofia antica sono certamente molto interessanti ma assai discutibili da un punto di vista storico-filosofico. L’autore si spinge fino a correggere Agostino stesso, soprattutto per quanto riguarda la componente pitagorica della sua riflessione, per sottolineare invece una componente religiosa della musica che non sembra così evidente nella riflessione agostiniana. H.-I. Marrou's Traité de la musique selon l'esprit de Saint Augustin (1942) is a useful document about the relationship between 1930s French music and non-conformist culture. His stress on the moral aim of music recalls the claim for a spiritual revolution that informs the spirit of 1930 and Jeune France's manifesto: the reading of Marrou's Traité helps us defining the humanistic poetics of music of the '30s, and the historical context mutually explains and justify most of Marrou's thought (otherwise apparently weak). His thought is in fact developed in the wake of Christian Platonism revised by Augustine, subject to a series of small changes in sight of a better and more relevant moral theology. The philosophical outcome isn't very convincing, both for many appeals to the authority principle, and for frequent contradictions clearly emerging in his arguments. The tension between the fidelity to the doctrine, the attempts to re-read the music from an apologetic viewpoint and the aim to suggest a practical philosophy produces a methodological setback so striking that it represents one of the greater limits of the Treaty. Marrou's remarks about the relationship between Christianity and ancient philosophy are certainly as interesting as questionable from the point of view of the history of philosophy. He goes so far to correct Augustine himself, especially as regards the Pythagorean influence on his thought, to stress instead a religious component of the music that doesn't seem so evident in the Augustinian analysis

Corrigendum: oscillatory activities in neurological disorders of elderly: biomarkers to target for neuromodulation

No abstract availble

Legume Ecotypes and Commercial Cultivars Differ in Performance and Potential Suitability for Use as Permanent Living Mulch in Mediterranean Vegetable Systems

Weed control in organic conservative vegetable systems is extremely challenging and the use of legume permanent living mulches (pLM) presents an interesting opportunity. The successful use of pLM is largely determined by the choice of appropriate legumes which are able to combine adequate weed control with a marginal competitive effect on the cash crop(s). However, the availability of legumes for such systems is limited and their characterization based on growth traits can support the selection of suitable legumes for conservation organic vegetable systems. The current study investigated weed control capacity and variability in morphological and phenological traits relevant in inter-plant competition among a range of 11 commercial cultivars of legumes and seven ecotypes of Medicago polymorpha (bur medic). For commercial cultivars, Lotus corniculatus (bird’s-foot trefoil) and Trifolium repens (white clover) showed the best weed control capacity, while Trifolium subterraneum (subterranean clover) and Medicago polymopha had more suitable characteristics for a rapid and complete establishment of the pLM. Overall, legume mulches appear more effective in dicotyledonous than in monocotyledonous weed control. Trifolium subterraneum cv. Antas and T. repens cv. Haifa were identified as the potentially most suitable legumes for use as pLM and their use in mixtures could be a promising solution. In addition, the ecotypes of Medicago polymorpha Manciano and Talamone proved to be well adapted for local environmental conditions and they showed a better weed suppression than the commercial cultivars of Medicago polymorpha

Senataxin Ortholog Sen1 Limits DNA:RNA Hybrid Accumulation at DNA Double-Strand Breaks to Control End Resection and Repair Fidelity

Summary: An important but still enigmatic function of DNA:RNA hybrids is their role in DNA double-strand break (DSB) repair. Here, we show that Sen1, the budding yeast ortholog of the human helicase Senataxin, is recruited at an HO endonuclease-induced DSB and limits the local accumulation of DNA:RNA hybrids. In the absence of Sen1, hybrid accumulation proximal to the DSB promotes increased binding of the Ku70-80 (KU) complex at the break site, mutagenic non-homologous end joining (NHEJ), micro-homology-mediated end joining (MMEJ), and chromosome translocations. We also show that homology-directed recombination (HDR) by gene conversion is mostly proficient in sen1 mutants after single DSB. However, in the absence of Sen1, DNA:RNA hybrids, Mre11, and Dna2 initiate resection through a non-canonical mechanism. We propose that this resection mechanism through local DNA:RNA hybrids acts as a backup to prime HDR when canonical pathways are altered, but at the expense of genome integrity