On the link between global volcanic activity and global mean sea level

Studying a large number of volcanic eruptions is a way to decipher general characteristics related to volcano dynamics but also on external forcing influencing it, such as solid Earth and ocean tides. Many studies have tackled this tidal influence on the onset of volcanic eruptions and more generally, on volcanic activity. However, the interplay between this quasi-permanent forcing and volcanic systems is still poorly understood. With the present study, we propose to consider a global viewpoint to address this interaction. We analyzed the number of monthly volcanic eruptions and the global mean sea level between 1880 and 2009 using the Singular Spectrum Analysis time-series analysis technique to evaluate the existence of common periodicities. We found multi-decadal components of similar periodicities present in both time-series which we link to those already recognized in the polar motion. Its multi-decadal variations result in a mass reorganization in the oceans whose associated stress changes may impact processes generating volcanic eruptions worldwide. Our results show the influence of global processes on volcanic activity and open many questions to further investigate these multi-scale interactions.info:eu-repo/semantics/publishedVersio

L’utopie inaugurale ou les prémices du mythe chez Vicente Huidobro

A partir de una lectura de la obra “primitiva” del poeta chileno Vicente Huidobro, el análisis busca establecer la coherencia y la unidad de la primera etapa de constitución de una obra. En estas primeras producciones (1912-1925), Huidobro desarrolla estrategias de escritura que refuerza de un poemario a otro, poniendo en escena figuras poéticas de una estatura tan grandiosa como el proyecto de escritura que ellas animan. La ambición o la utopía “creacionista”, reivindicada en numerosos manifiestos huidobrianos del período, constituye el hilo conductor de este proyecto original, paralelo al que estructura la arquitectura semántica y conceptual de los poemarios. Este sueño inaugural se encarna de manera particular en Adán (1916), primera definición sublimada del Poeta “hacedor” de mundos ; un Adán que se determina también como anticipación de Altazor (1931). Es en este corpus primitivo que comienza a escribirse la historia - o la prehistoria – de un mito en perpetua evolución.A partir d’une lecture des recueils « primitifs » du poète chilien Vicente Huidobro, l’analyse vise à établir une cohérence et une unité au sein de la démarche initiale de fondation d’une œuvre. Ces premières productions (1912-1925) développent des stratégies d’écriture renforcées d’un recueil à l’autre, et mettent en scène des figures poétiques à la stature aussi démesurément grandiose que le projet d’écriture qu’elles soutiennent. De ce projet original, l’ambition ou l’utopie « créationniste », revendiquée dans les nombreux manifestes huidobriens de la période, est la parallèle directrice structurant l’architecture sémantique et conceptuelle des recueils. Ce rêve de l’inauguralité se voit porté plus particulièrement par la figure précoce de l’Adán de 1916, première définition sublimée du Poète « faiseur » de mondes ; un Adán qui se détermine aussi comme anticipation de l’Altazor de 1931. Dans ce corpus primitif, c’est l’histoire, ou la pré-histoire d’un mythe en devenir qui commence à s’écrire.Based on a reading of the early poetry collections of Chilean poet Vicente Huidobro, this article aims to show the coherence of Huidobro’s poetic practice in the founding works of his œuvre. Successive early works (1912-1925) see the steady development of Huidobro’s writing strategies and the genesis of a series of figures of the poet as disproportionately grandiose as the writing project which they represent. The “creationist” ambition of these works, an ambition which was a feature of the poet’s many manifestos of the period, is the guiding principal governing their semantic and structural architecture. This imaginary beginning or genesis is particularly embodied by the figure of Adán (Adán, 1916), the first incarnation of the Poet as creator of worlds, and precursor of the later figure, Altazor (Altazor, 1931). These early works can thus be read as a kind history, or pre-history of Huidobro’s later poetic myth

Evidence of earthquake seasonality in the Azores Triple Junction

This work presents evidence of seasonal and inter-annual variations of the earthquake occurrence rate in the Azores Triple Junction, on the Mid-Atlantic Ridge (MAR). Annual cycles in microearthquakes are relatively common in intraplate continental regions afected by large hydrological loads, but this is the frst time that earthquake seasonality is recognized near mid-ocean ridges. First, we benchmark the methodology by matching the published results of earthquake seasonality in the intraplate New Madrid Seismic Zone (USA). Next, we analyze the Azores earthquake catalogue, from 2008 to 2018, separately for oceanic and island regions. The results demonstrate that the seasonal modulation of the seismicity rate is only observed in the ocean, especially in the vicinity of the triple junction, with more earthquakes occurring during the summer months from May to August. Monte Carlo simulations show that the probability of observing such seasonality by chance is less than 1% for the magnitude band from 3.3 to 4.5, well above the detection threshold and magnitude of completeness of the seismic catalogue. The methodology includes a Jack-Knife approach, which shows that the oceanic seasonality is not the consequence of abnormal or extreme events. Although we speculate about possible earthquake triggering processes, it remains a challenge to defnitely establish the mechanism responsible for the observed earthquake seasonal modulation in the Azores.info:eu-repo/semantics/publishedVersio

Seasonal modulation of oceanic seismicity in the azores

The analysis of an 11-year (2008-2018) seismic catalogue of the Azores suggests the existence of secondary cyclic influences on the seismicity rate of the oceanic region, with more earthquakes observed during the summer months, from May to August, than in winter. Statistical testing based on Monte-Carlo simulations and a Jack-Knife methodology indicate that the seasonal modulation affects earthquakes with magnitudes M3.3-4.5, well above the magnitude of completeness. Here, we investigate the seasonal variations of earthquake rate considering both the whole Azores oceanic domain and four separate sub-regions, corresponding to four regional clusters identified by previous authors. The analysis shows that the seasonal modulation is particularly observed near the Triple Junction region between the Faial Island and the Mid-Atlantic Ridge. To identify possible mechanisms driving the seasonal modulation, we apply Singular Spectral Analysis to the seismicity rate and to time-series of plausible external triggers, in order to investigate possible common periodicities. We find significant correlations between the earthquake rate, sea level anomaly rate, GRACE satellite anomalies and ocean bottom pressure, suggesting that water load may modulate the Azores oceanic seismicity.info:eu-repo/semantics/publishedVersio

Regards sur les paradigmes féministes en recherche

Huit spécialistes ont accepté de répondre à trois questions sur l’émergence, la variété et l’avenir des paradigmes féministes en recherche. Ces personnes viennent d’universités différentes, de disciplines différentes et font aussi partie de générations différentes.Cette discussion n’a pas vraiment eu lieu, et c’est pourquoi elle est qualifiée de « virtuelle ». Toutefois, un échange a pu être constitué avec les réponses reçues. Il témoigne d’opinions contrastées, allant de l’optimisme au pessimisme, au sujet de l’influence des paradigmes féministes sur l’ensemble de la recherche universitaire.Eight professors were invited to answer three questions on the apparition, the variety and the future of feminist paradigms in research. They come from different universities, different disciplines and different generations. This discussion is called "virtual", because the participants have never met. The dialogue presented has been fabricated with the answers received. It reveals contrasted opinions, from optimism to pessimism, about the influence of feminist paradigms on the whole of learned research

L’éducation des adultes chez les 16 à 18 ans : La volonté de réussir l’école… et la vie!

Comment expliquer l’utilisation quasi automatique des programmes de formation aux adultes par une majorité d’élèves de 16 à 18 ans vus comme étant des élèves handicapés ou en difficulté d’apprentissage ou d’adaptation (EHDAA) au secteur jeunes? Ce passage de l’école des jeunes à celle des adultes est-il lié à des aspirations professionnelles légitimes? Une étude de cas de type microtechnographique (Bogdan et Biklen, 1998) a permis de documenter les raisons qui motivent les jeunes de 16 à 18 ans ayant des difficultés à recourir à l’éducation des adultes. Cette même étude a aussi permis de mieux comprendre l’expérience scolaire de ces jeunes, de même que les fondements derrière leur décision d’arrêter ou de poursuivre leur formation scolaire.How can we explain the almost automatic use of adult education programs by the majority of 16 to 18 year-old students identified as handicapped or with learning or adaptation problems? Is the transition students make from high school to adult education classes linked to legitimate professional goals? A micro-technographic type case study (Bogdan and Biklen, 1998) documented reasons motivating 16 to 18 year-olds who have trouble going on to adult education. This study also provided a better understanding of the scholastic experiences of these students, as well as the reasons behind their decision to abandon or continue their education.¿Cómo explicar la utilización casi automática de los programas de formación para adultos que hace un número importante de alumnos entre 16 y 18 años, identificados como alumnos minusválidos o con dificultades de aprendizaje o de adaptación (EHDAA) en las escuelas públicas? ¿El paso de la escuela hacia la educación para adultos está ligado a aspiraciones profesionales legítimas? Un estudio de caso de tipo microtecnográfico (Bogdan y Biklen, 1998) permitió documentar las razones que motivan a los jóvenes de 16 a 18 años que confrontaban dificultades y que optaron por la educación para adultos. Este mismo estudio también nos ha permitido comprender más cabalmente la experiencia escolar de dichos jóvenes, así como las bases sobre las que se apoya su decisión de cesar o de continuar su escolarización

Seasonal modulation of oceanic seismicity in the azores

The analysis of an 11-year (2008–2018) seismic catalogue of the Azores suggests the existence of secondary cyclic influences on the seismicity rate of the oceanic region, with more earthquakes observed during the summer months, from May to August, than in winter. Statistical testing based on Monte-Carlo simulations and a Jack-Knife methodology indicate that the seasonal modulation affects earthquakes with magnitudes M3.3–4.5, well above the magnitude of completeness. Here, we investigate the seasonal variations of earthquake rate considering both the whole Azores oceanic domain and four separate sub-regions, corresponding to four regional clusters identified by previous authors. The analysis shows that the seasonal modulation is particularly observed near the Triple Junction region between the Faial Island and the Mid-Atlantic Ridge. To identify possible mechanisms driving the seasonal modulation, we apply Singular Spectral Analysis to the seismicity rate and to time-series of plausible external triggers, in order to investigate possible common periodicities. We find significant correlations between the earthquake rate, sea level anomaly rate, GRACE satellite anomalies and ocean bottom pressure, suggesting that water load may modulate the Azores oceanic seismicity

Transient self-potential anomalies associated with recent lava flows at Piton de la Fournaise volcano (Réunion Island, Indian Ocean)

International audienceSelf-potential signals are sensitive to various phenomena including ground water flow (streaming potential), thermal gradients (thermoelectric potential), and potentially rapid fluid disruption associated with vaporization of water. We describe transient self-potential anomalies observed over recent (< 9 years) lava flows at Piton de la Fournaise volcano (Reunion Island, Indian Ocean). Repeated self-potential measurements are used to determine the decay of the self-potential signals with time since the emplacement of a set of lava flow. We performed a 9 km-long self-potential profile in February 2004 in the Grand Brûlé area. This profile was repeated in July–August 2006. The second repetition of this profile crossed eight lava flows emplaced between 1998 and 2005 during seven eruptions of Piton de la Fournaise volcano. The self-potential data show clear positive anomalies (up to 330 mV) and spatially correlated with the presence of recent lava flows. The amplitude of the self-potential anomalies decreases exponentially with the age of the lava flows with a relaxation time of not, vert, similar 44 months. We explain these anomalies by the shallow convection of meteoric water and the associated streaming potential distribution but we cannot exclude possible contributions from the thermoelectric effect and the rapid fluid disruption mechanism. This field case evidences for the first time transient self-potential signals associated with recent volcanic deposits. It can be also a shallow analogue to understand the variation of self-potential signals in active geothermal areas and transient self-potential signals associated with dike intrusion at larger depths. The empirical equation we proposed can also be used to diagnose the cooling of recent lava flow on shield volcanoes

Rev-erbα in the brain is essential for circadian food entrainment.

Foraging is costly in terms of time and energy. An endogenous food-entrainable system allows anticipation of predictable changes of food resources in nature. Yet the molecular mechanism that controls food anticipation in mammals remains elusive. Here we report that deletion of the clock component Rev-erbα impairs food entrainment in mice. Rev-erbα global knockout (GKO) mice subjected to restricted feeding showed reduced elevations of locomotor activity and body temperature prior to mealtime, regardless of the lighting conditions. The failure to properly anticipate food arrival was accompanied by a lack of phase-adjustment to mealtime of the clock protein PERIOD2 in the cerebellum, and by diminished expression of phosphorylated ERK 1/2 (p-ERK) during mealtime in the mediobasal hypothalamus and cerebellum. Furthermore, brain-specific knockout (BKO) mice for Rev-erbα display a defective suprachiasmatic clock, as evidenced by blunted daily activity under a light-dark cycle, altered free-running rhythm in constant darkness and impaired clock gene expression. Notably, brain deletion of Rev-erbα totally prevented food-anticipatory behaviour and thermogenesis. In response to restricted feeding, brain deletion of Rev-erbα impaired changes in clock gene expression in the hippocampus and cerebellum, but not in the liver. Our findings indicate that Rev-erbα is required for neural network-based prediction of food availability.journal article2016 Jul 062016 07 06importe