3,206 research outputs found
Testing Gravitational Memory Generation with Compact Binary Mergers
No full textGravitational memory is an important prediction of General Relativity, which is intimately related to asymptotic symmetries at null infinity and the so-called soft graviton theorem. For a given transient astronomical event, the angular distribution of energy and angular momentum fluxes uniquely determine the displacement and spin memory effect in the sky. We investigate the possibility of using the binary black hole merger events detected by Advanced LIGO/Virgo to test the relation between the source’s energy emission and the gravitational memory measured on Earth, as predicted by General Relativity. We find that while it is difficult for Advanced LIGO/Virgo one-year detection of a third-generation detector network will easily rule out the hypothesis assuming isotropic memory distribution. In addition, we construct a phenomenological model for memory waveforms of binary neutron star mergers and use it to address the detectability of memory from these events in the third-generation detector era. We find that measuring gravitational memory from neutron star mergers is a possible way to distinguish between different neutron star equations of state
Contrasting activity profile of two distributed cortical networks as a function of attentional demands
No full textThe original publication is available at http://www.jneurosci.orgThis work was supported by R01 grant MH-073610 from the National Institutes of Health to Denis Paré
Towards the design of gravitational-wave detectors for probing neutron-star physics
No full textThe gravitational waveform of merging binary neutron stars encodes information about extreme states of matter. Probing these gravitational emissions requires the gravitational-wave detectors to have high sensitivity above 1 kHz. Fortunately for current advanced detectors, there is a sizeable gap between the quantum-limited sensitivity and the classical noise at high frequencies. Here we propose a detector design that closes such a gap by reducing the high-frequency quantum noise with an active optomechanical filter, frequency-dependent squeezing, and high optical power. The resulting noise level from 1 to 4 kHz approaches the current facility limit and is a factor of 20 to 30 below the design of existing advanced detectors. This will allow for precision measurements of (i) the postmerger signal of the binary neutron star, (ii) late-time inspiral, merger, and ringdown of low-mass black hole–neutron star systems, and possible detection of (iii) high-frequency modes during supernovae explosions. This design tries to maximize the science return of current facilities by achieving a sensitive frequency band that is complementary to the longer-baseline third-generation detectors: the 10 km Einstein Telescope and 40 km Cosmic Explorer. We have highlighted the main technical challenges towards realizing the design, which requires dedicated research programs. If demonstrated in current facilities, the techniques can be transferred to new facilities with longer baselines.National Science Foundation (U.S.)Kavli Foundatio
Gravitationally induced phase shift on a single photon
No full textThe effect of the Earth's gravitational potential on a quantum wave function has only been observed for massive particles. In this paper we present a scheme to measure a gravitationally induced phase shift on a single photon traveling in a coherent superposition along different paths of an optical fiber interferometer. To create a measurable signal for the interaction between the static gravitational potential and the wave function of the photon, we propose a variant of a conventional Mach–Zehnder interferometer. We show that the predicted relative phase difference of 10⁻⁵ rad is measurable even in the presence of fiber noise, provided additional stabilization techniques are implemented for each arm of a large-scale fiber interferometer. Effects arising from the rotation of the Earth and the material properties of the fibers are analysed. We conclude that optical fiber interferometry is a feasible way to measure the gravitationally induced phase shift on a single-photon wave function, and thus provides a means to corroborate the equivalence of the energy of the photon and its effective gravitational mass
Is Tolerance Political? An Interview with Denis Lacorne
No full textcontribution à un site webDenis Lacorne is the author of "The Limits of Tolerance. Enlightenment Values and Religious Fanaticism" (Columbia University Press, 2019), the English translation of "Les limites de la tolérance" (Gallimard, awarded the Prix Montyon by the Académie Française). In his book, which is intellectually very inspiring because of the many questions it addresses and raises, Denis Lacorne traces the emergence of the notion of tolerance from its early thinkers to the Age of Enlightenment and finally questions the notion and its various understandings through more recent events in France and the United States. What is tolerance? Is tolerance political? Interview by Miriam Périer, CER
Chaetogammarus MARTYNOV 1924
No full textGENUS <i>CHAETOGAMMARUS</i> MARTYNOV, 1924 <p> <i>Type species:</i> <i>Gammarus ischnus</i> Stebbing, 1899.</p> <p> <i>I n c l u d e d s p e c i e s: C h a e t o g a m m a r u s h y r c a n u s</i> Pjatakova 1962, <i>C. pauxillus</i> (Sars, 1896), <i>C. placidus</i> (Sars, 1896), <i>C. aearpachoaeskyi</i> (Sars, 1894) and <i>C. trichiatus</i> Martynov, 1932.</p> <p> <i>Non-included species:</i> <i>Echinogammarus karadagiensis</i> Grintsov, 2009 and <i>E. mazestiensis</i> Marin & Palatov, 2020 will be transferred to a new genus (I. Marin, D. Palatov, and D. CopilaȘ- Ciocianu, unpub. obs.).</p> <p> <i>Amended diagnosis:</i> Small- to large-sized species (≤ 15 mm); females smaller than males. Head with oblique anteroventral lobe, sometimes distally produced. Eyes large, reniform, well pigmented. Body non-carinate. Antenna 1 feebly setose, accessory flagellum two- to eight-segmented; antenna 2 usually shorter that antenna 1, without calceoli, deeply setose in males and less setose in females. Lower lip (labium) with mostly reduced inner lobes. Gnathopod 1 smaller than gnathopod 2, sexually dimorphic, stronger in males, propodus generally teardrop shaped; gnathopod 2 sexually dimorphic, stronger in males, propodus trapezoidal with oblique palmar margin. Basis of pereopods 5–7 without or with weak posteroventral lobes, dominated by spines. Uropod 3 with exopod about four to six times as long as wide, generally dominated by spines. Urosomites 1 and 2 without elevations, armed with clusters of spines; urosomite 3 with a pair of submedian spines. Telson deeply cleft into suboval lobes, bearing clusters of spines distally and submedially.</p> <p> <i>Synonymized genera:</i> <i>Trichogammarus</i> Hou & Sket, 2016.</p> <p> <i>Distribution:</i> The native range of the genus is restricted to the Ponto-Caspian basin. Its species occur in the Caspian Sea at up to 500 m depth, and in lagoons, estuaries and lower stretches of rivers that drain into the Black, Azov and Caspian seas.</p>Published as part of <i>Copilaș-Ciocianu, Denis, Palatov, Dmitry, Rewicz, Tomasz, Sands, Arthur F., Arbačiauskas, Kęstutis, Haaren, Ton Van, Hebert, Paul D. N., Grabowski, Michał & Marin, Ivan, 2023, A widespread Ponto-Caspian invader with a mistaken identity: integrative taxonomy elucidates the confusing taxonomy of Trichogammarus trichiatus (= Echinogammarus) (Crustacea: Amphipoda), pp. 821-846 in Zoological Journal of the Linnean Society 198</i> on pages 833-834, DOI: 10.1093/zoolinnean/zlad010, <a href="http://zenodo.org/record/8152446">http://zenodo.org/record/8152446</a>
Timing of impulses from the central amygdala and bed nucleus of the stria terminalis to the brainstem
No full textThe amygdala and bed nucleus of the stria terminalis (BNST) are thought to subserve distinct functions with the former mediating rapid fear responses to discrete sensory cues and the latter longer “anxiety-like” states in response to diffuse environmental contingencies. Yet, these structures are reciprocally connected and their projection sites overlap extensively. To shed light on the significance of BNST-amygdala connections, we compared the antidromic response latencies of BNST and central amygdala (CE) neurons to brainstem stimulation. Whereas the frequency distribution of latencies was unimodal in BNST neurons (~10 ms mode), that of CE neurons was bimodal (~10 and ~30 ms modes). However, after stria terminalis (ST) lesions, only short-latency antidromic responses were observed, suggesting that CE axons with long conduction times course through the ST. Compared to the direct route, the ST greatly lengthens the path of CE axons to the brainstem, an apparently disadvantageous arrangement. Since BNST and CE share major excitatory basolateral amygdala (BL) inputs, lengthening the path of CE axons might allow synchronization of BNST and CE impulses to brainstem when activated by BL. To test this, we applied electrical BL stimuli and compared orthodromic response latencies in CE and BNST neurons. The latency difference between CE and BNST neurons to BL stimuli approximated that seen between the antidromic responses of BNST cells and CE neurons with long-conduction times. These results point to a hitherto unsuspected level of temporal coordination between the inputs and outputs of CE and BNST neurons, supporting the idea of shared functions.The original publication is available at: http://jn.physiology.org/cgi/content/full/100/6/342
Rehab Depot de la Plaine Saint-Denis
No full textRedesign for workshop Atelier Revision Intermediaire at the Depot de la Plaine Saint-Denis with a rehabilitation center as new functionRMITArchitecture and The Built Environmen
Severini e Denis
No full textL'A. prende in esame i controversi rapporti tra i due artisti, nel primo decennio del secolo e, più tardi, nella produzione di carattere religioso. Severini risulta influenzato da Denis più di quanto sostenga negli scritti teorici. The Author examines the controversial relationships between the two artists, in the first decade of the century and later on, in their religious production. Severini appears influenced by Denis more than he declares in his theoretic writings
The bed nucleus of the stria terminalis mediates inter-individual variations in anxiety and fear
No full textWhile learning to fear stimuli that predict danger promotes survival, the inability to inhibit fear to inappropriate cues leads to a pernicious cycle of avoidance behaviors. Previous studies have revealed large inter-individual variations in fear responding with clinically anxious humans exhibiting a tendency to generalize learned fear to safe stimuli or situations. To shed light on the origin of these inter-individual variations, we subjected rats to a differential auditory fear conditioning paradigm where one conditioned auditory stimulus (CS+) was paired to footshocks whereas a second (CS-) was not. We compared the behavior of rats that received pre-training excitotoxic lesions of the bed nucleus of the stria terminalis (BNST) to that of sham rats. Sham rats exhibit a continuum of anxious/fearful behaviors. At one end of the continuum were rats that displayed a poor ability to discriminate between the CS+ and CS-, high contextual freezing, and an anxiety-like trait in the elevated plus maze (EPM). At the other end were rats that display less fear generalization to the CS-, lower freezing to context, and a non-anxious trait on the EPM. Although BNST-lesioned rats acquired similarly high levels of conditioned fear to the CS+, they froze less than sham rats to the CS-. In fact, BNST-lesioned rats behaved like sham rats with high discriminative abilities in that they exhibited low contextual fear and a nonanxious phenotype in the EPM. Overall, this suggests that inter-individual variations in fear generalization and anxiety phenotype are determined by BNST influences on the amygdala and/or its targets.Published in Journal of Neuroscience. Copyright Society for Neuroscience.Available from the Journal of Neuroscience: http://www.jneurosci.org
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