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245 results on '"Absil, P."'

1. Low-Loss Silicon Directional Coupler With Arbitrary Coupling Ratios for Broadband Wavelength Operation Based on Bent Waveguides

Author

El-Saeed, Ahmed H., Elshazly, Alaa, Kobbi, Hakim, Magdziak, Rafal, Lepage, Guy, Marchese, Chiara, Vaskasi, Javad Rahimi, Bipul, Swetanshu, Bode, Dieter, Filipcic, Marko Ersek, Velenis, Dimitrios, Chakrabarti, Maumita, De Heyn, Peter, Verheyen, Peter, Absil, Philippe, Ferraro, Filippo, Ban, Yoojin, Van Campenhout, Joris, Bogaerts, Wim, and Deng, Qingzhong

Abstract

We demonstrate a design for a high-performance $2 \times 2$ splitter meeting the essential requirements of broadband coupling, support for arbitrary coupling ratio, ultra low-loss, high fabrication tolerance, and a compact footprint. This is achieved based on a rigorous coupled mode theory analysis of the broadband response of the bent directional coupler (DC) and by demonstrating a full coupling model, with measured broadband values of 0.4, 0.5, 0.6, and 0.7. As a benchmark, we demonstrate a 0.5:0.5 splitter that significantly reduces coupling variation from 0.391 in the traditional DC to just 0.051 over an 80 nm wavelength span. This represents a remarkable 7.67 times reduction in coupling variation. Further, newly-invented low-loss bends were used in the proposed design leading to an ultra low-loss design with negligible excess loss ($\mathrm{0.003 \pm 0.013 \ dB}$). The proposed 0.5:0.5 silicon strip waveguide-based design is tolerant and shows consistently low coupling variation over a full 300 mm wafer showcasing a maximum cross coupling variation of 0.112 over 80 nm wavelength range, at the extreme edge of the wafer. Futhermore, we augmented the wafer mapping with a waveguide width fabrication tolerance study, confirming the tolerance of the device with a mere 0.061 maximum coupling variation with a waveguide width deviation of $\pm 20$ nm over 80 nm wavelength range. These specs make the proposed splitter an attractive component for practical applications with mass production.

Published
2024
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3. The Large Interferometer For Exoplanets (LIFE): a space mission for mid-infrared nulling interferometry

Author

Kammerer, Jens, Sallum, Stephanie, Sanchez-Bermudez, Joel, Glauser, Adrian M., Quanz, Sascha P., Hansen, Jonah, Dannert, Felix, Ireland, Michael, Linz, Hendrik, Absil, Olivier, Alei, Eleonora, Angerhausen, Daniel, Birbacher, Thomas, Defrère, Denis, Fortier, Andrea, Huber, Philipp A., Kammerer, Jens, Laugier, Romain, Lichtenberg, Tim, Noack, Lena, Ranganathan, Mohanakrishna, Rugheimer, Sarah, Airapetian, Vladimir, Alibert, Yann, Amado, Pedro J., Anger, Marius, Anugu, Narsireddy, Aragon, Max, Armstrong, David J., Balbi, Amedeo, Balsalobre-Ruza, Olga, Banik, Deepayan, Beck, Mathias, Bhattarai, Surendra, Biren, Jonas, Bottoni, Jacopo, Braam, Marrick, Brandeker, Alexis, Buchhave, Lars A., Caballero, José A., Cabrera, Juan, Carone, Ludmila, Carrión-González, Óscar, Castro-González, Amadeo, Chan, Kenny, Coelho, Ligia F., Constantinou, Tereza, Cowan, Nicolas, Danchi, William, Dandumont, Colin, Davoult, Jeanne, Dawn, Arjun, de Vera, Jean-Pierre P., de Visser, Pieter J., Dorn, Caroline, Duque Lara, Juan A., Elowitz, Mark, Ertel, Steve, Fang, Yuedong, Felix, Simon, Fortney, Jonathan, Fridlund, Malcolm, García Muñoz, Antonio, Gillmann, Cedric, Golabek, Gregor, Grenfell, John Lee, Guidi, Greta, Guilera, Octavio, Hagelberg, Janis, Hansen, Janina, Haqq-Misra, Jacob, Hara, Nathan, Helled, Ravit, Herbst, Konstantin, Hernitschek, Nina, Hinkley, Sasha, Ito, Takahiro, Itoh, Satoshi, Ivanovski, Stavro, Janson, Markus, Johansen, Anders, Jones, Hugh, Kane, Stephen, Kitzmann, Daniel, Kovacevic, Andjelka B., Kraus, Stefan, Krause, Oliver, Kruijssen, J. M. Diederik, Kuiper, Rolf, Kuriakose, Alen, Labadie, Lucas, Lacour, Sylvestre, Lanza, Antonino F., Leedjärv, Laurits, Lendl, Monika, Leung, Michaela, Lillo-Box, Jorge, Loicq, Jérôme, Luque, Rafael, Mahadevan, Suvrath, Majumdar, Liton, Malbet, Fabien, Mallia, Franco, Mathew, Joice, Matsuo, Taro, Matthews, Elisabeth, Meadows, Victoria, Mennesson, Bertrand, Meyer, Michael R., Molaverdikhani, Karan, Mollière, Paul, Monnier, John, Navarro, Ramon, Nsamba, Benard, Oguri, Kenshiro, Oza, Apurva, Palle, Enric, Persson, Carina, Pitman, Joe, Plávalová, Eva, Pozuelos, Francisco J., Quirrenbach, Andreas, Ramirez, Ramses, Reiners, Ansgar, Ribas, Ignasi, Rice, Malena, Ricketti, Berke Vow, Roelfsema, Peter, Romagnolo, Amedeo, Ronco, María Paula, Schlecker, Martin, Schonhut-Stasik, Jessica, Schwieterman, Edward, Sefilian, Antranik A., Serabyn, Eugene, Shahi, Chinmay, Sharma, Siddhant, Silva, Laura, Singh, Swapnil, Sneed, Evan L., Spencer, Locke, Squicciarini, Vito, Staguhn, Johannes, Stapelfeldt, Karl, Stassun, Keivan, Tamura, Motohide, Taysum, Benjamin, van der Tak, Floris, van Kempen, Tim A., Vasisht, Gautam, Wang, Haiyang S., Wordsworth, Robin, and Wyatt, Mark

Published
2024
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5. L-band nulling interferometry at the VLTI with Asgard/NOTT: status and plans

Author

Kammerer, Jens, Sallum, Stephanie, Sanchez-Bermudez, Joel, Defrère, Denis, Laugier, Romain, Martinod, Marc-Antoine, Garreau, Germain, Missiaen, Kwinten, Salman, Muhammad, Raskin, Gert, Dandumont, Colin, Ertel, Steve, Ireland, Michael J., Kraus, Stefan, Labadie, Lucas, Mazzolli, Alexandra, Medgyesi, Gyorgy, Sanny, Ahmed, Absil, Olivier, Ábráham, Peter, Berger, Jean-Philippe, Bonduelle, Myriam, Bigioli, Azzurra, Bouzerand, Emilie, Carter, Josh, Cvetojevic, Nick, Courtney-Barrer, Benjamin, Glauser, Adrian M., Gross, Simon, Haubois, Xavier, James, Noel, Joo, Andras Peter, Lagarde, Stephane, Léger, Alain, Leisenring, Jarron, Loicq, Jérôme, Martin, Guillermo, Martinache, Frantz, Mezo, Gyorgy, Morel, Sébastien, Morren, Johan, Ollivier, Marc, Robertson, Gordon, Rousseau, Hélène, Schofield, Warrick, Schuhler, Nicolas, Taras, Adam, Vandenbussche, Bart, and Woillez, Julien

Published
2024
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6. The ELT/METIS annular groove phase masks

Author

Navarro, Ramón, Jedamzik, Ralf, Delacroix, Christian, König, Lorenzo, Absil, Olivier, Orban De Xivry, Gilles, Forsberg, Pontus, Karlsson, Mikael, Ronayette, Samuel, Pantin, Eric, and Barrière, Jean-Christophe

Published
2024
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11. METIS AOCS at the beginning of MAIT

Author

Ibsen, Jorge, Chiozzi, Gianluca, Kulas, Martin, Absil, Oliver, Bertram, Thomas, Briegel, Florian, Coppejans, Hugo, Correia, Carlos, De Meester, Wim, Feldt, Markus, Naranjo, Vianak, Obereder, Andreas, Orban de Xivry, Gilles, and Steuer, Horst

Published
2024
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12. Upgrading SPHERE with the second stage AO system SAXO+: non-common path aberrations estimation and correction

Author

Bryant, Julia J., Motohara, Kentaro, Vernet, Joël R. D., Mazoyer, Johan, Goulas, Charles, Vidal, Fabrice, Bernardino Dinis, Isaac, Milli, Julien, Tallon, Michel, Galicher, Raphaël, Absil, Olivier, Bechet, Clémentine, Boccaletti, Anthony, Ferreira, Florian, Langlois, Maud, Martinez, Patrice, Mugnier, Laurent, N'diaye, Mamadou, Orban de Xivry, Gilles, Potier, Axel, Tallon-Bosc, Isabelle, and Vigan, Arthur

Published
2024
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13. Interrupted SNAr-Alkylation Dearomatization

Author

Altundas, Bilal, Marrazzo, John-Paul R., Brinck, Tore, Absil, Christopher, and Fleming, Fraser F.

Abstract

Dearomatizations provide powerful synthetic routes to rapidly assemble substituted carbocycles and heterocycles found in a plethora of bioactive molecules. Harnessing the advantages of dearomatization typically requires vigorous reagents because of the difficulty in disrupting the stable aromatic core. A relatively mild dearomatization strategy is described that employs lithiated nitriles or isocyanides in a simple SNAr-type addition to form σ-complexes that are trapped by alkylation. The dearomatizations are diastereoselective and efficient and rapidly install two new carbon–carbon bonds, one of which is a quaternary center, as well as nitrile, isocyanide, and cyclohexadiene functionalities.

Published
2024
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14. SO2, silicate clouds, but no CH4detected in a warm Neptune

Author

Dyrek, Achrène, Min, Michiel, Decin, Leen, Bouwman, Jeroen, Crouzet, Nicolas, Mollière, Paul, Lagage, Pierre-Olivier, Konings, Thomas, Tremblin, Pascal, Güdel, Manuel, Pye, John, Waters, Rens, Henning, Thomas, Vandenbussche, Bart, Ardevol Martinez, Francisco, Argyriou, Ioannis, Ducrot, Elsa, Heinke, Linus, van Looveren, Gwenael, Absil, Olivier, Barrado, David, Baudoz, Pierre, Boccaletti, Anthony, Cossou, Christophe, Coulais, Alain, Edwards, Billy, Gastaud, René, Glasse, Alistair, Glauser, Adrian, Greene, Thomas P., Kendrew, Sarah, Krause, Oliver, Lahuis, Fred, Mueller, Michael, Olofsson, Goran, Patapis, Polychronis, Rouan, Daniel, Royer, Pierre, Scheithauer, Silvia, Waldmann, Ingo, Whiteford, Niall, Colina, Luis, van Dishoeck, Ewine F., Östlin, Göran, Ray, Tom P., and Wright, Gillian

Abstract

WASP-107b is a warm (approximately 740 K) transiting planet with a Neptune-like mass of roughly 30.5 M⊕and Jupiter-like radius of about 0.94 RJ(refs. 1,2), whose extended atmosphere is eroding3. Previous observations showed evidence for water vapour and a thick, high-altitude condensate layer in the atmosphere of WASP-107b (refs. 4,5). Recently, photochemically produced sulfur dioxide (SO2) was detected in the atmosphere of a hot (about 1,200 K) Saturn-mass planet from transmission spectroscopy near 4.05 μm (refs. 6,7), but for temperatures below about 1,000 K, sulfur is predicted to preferably form sulfur allotropes instead of SO2(refs. 8–10). Here we report the 9σdetection of two fundamental vibration bands of SO2, at 7.35 μm and 8.69 μm, in the transmission spectrum of WASP-107b using the Mid-Infrared Instrument (MIRI) of JWST. This discovery establishes WASP-107b as the second irradiated exoplanet with confirmed photochemistry, extending the temperature range of exoplanets exhibiting detected photochemistry from about 1,200 K down to about 740 K. Furthermore, our spectral analysis reveals the presence of silicate clouds, which are strongly favoured (around 7σ) over simpler cloud set-ups. Furthermore, water is detected (around 12σ) but methane is not. These findings provide evidence of disequilibrium chemistry and indicate a dynamically active atmosphere with a super-solar metallicity.

Published
2024
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15. Integrated photonic-based coronagraphic systems for future space telescopes

Author

Ruane, Garreth J., Desai, Niyati, König, Lorenzo, Por, Emiel, Juanola-Parramon, Roser, Belikov, Ruslan, Laginja, Iva, Guyon, Olivier, Pueyo, Laurent, Fogarty, Kevin, Absil, Olivier, Altinier, Lisa, Baudoz, Pierre, Bidot, Alexis, Bonse, Markus Johannes, Bott, Kimberly, Brandl, Bernhard, Carlotti, Alexis, Casewell, Sarah L., Choquet, Elodie, Cowan, Nicolas B., Doelman, David, Fowler, J., Gebhard, Timothy D., Gutierrez, Yann, Haffert, Sebastiaan Y., Herscovici-Schiller, Olivier, Hours, Adrien, Kenworthy, Matthew, Kleisioti, Elina, Krasteva, Mariya, Landman, Rico, Leboulleux, Lucie, Mazoyer, Johan, Millar-Blanchaer, Maxwell A., Mouillet, David, N'Diaye, Mamadou, Snik, Frans, van Dam, Dirk, van Gorkom, Kyle, van Kooten, Maaike, and Vaughan, Sophia R.

Published
2023
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16. Visible extreme adaptive optics on extremely large telescopes: towards detecting oxygen in Proxima Centauri b and analogs

Author

Ruane, Garreth J., Fowler, J., Haffert, Sebastiaan Y., van Kooten, Maaike A. M., Landman, Rico, Bidot, Alexis, Hours, Adrien, N'Diaye, Mamadou, Absil, Olivier, Altinier, Lisa, Baudoz, Pierre, Belikov, Ruslan, Bonse, Markus Johannes, Bott, Kimberly, Brandl, Bernhard, Carlotti, Alexis, Casewell, Sarah L., Choquet, Elodie, Cowan, Nicolas B., Desai, Niyati, Doelman, David, Fogarty, Kevin, Gebhard, Timothy D., Gutierrez, Yann, Guyon, Olivier, Herscovici-Schiller, Olivier, Juanola-Parramon, Roser, Kenworthy, Matthew, Kleisioti, Elina, König, Lorenzo, Krasteva, Mariya, Laginja, Iva, Leboulleux, Lucie, Mazoyer, Johan, Millar-Blanchaer, Maxwell A., Mouillet, David, Por, Emiel, Pueyo, Laurent, Snik, Frans, van Dam, Dirk, van Gorkom, Kyle, and Vaughan, Sophia R.

Published
2023
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21. 15NH3in the atmosphere of a cool brown dwarf

Author

Barrado, David, Mollière, Paul, Patapis, Polychronis, Min, Michiel, Tremblin, Pascal, Ardevol Martinez, Francisco, Whiteford, Niall, Vasist, Malavika, Argyriou, Ioannis, Samland, Matthias, Lagage, Pierre-Olivier, Decin, Leen, Waters, Rens, Henning, Thomas, Morales-Calderón, María, Guedel, Manuel, Vandenbussche, Bart, Absil, Olivier, Baudoz, Pierre, Boccaletti, Anthony, Bouwman, Jeroen, Cossou, Christophe, Coulais, Alain, Crouzet, Nicolas, Gastaud, René, Glasse, Alistair, Glauser, Adrian M., Kamp, Inga, Kendrew, Sarah, Krause, Oliver, Lahuis, Fred, Mueller, Michael, Olofsson, Göran, Pye, John, Rouan, Daniel, Royer, Pierre, Scheithauer, Silvia, Waldmann, Ingo, Colina, Luis, van Dishoeck, Ewine F., Ray, Tom, Östlin, Göran, and Wright, Gillian

Abstract

Brown dwarfs serve as ideal laboratories for studying the atmospheres of giant exoplanets on wide orbits, as the governing physical and chemical processes within them are nearly identical1,2. Understanding the formation of gas-giant planets is challenging, often involving the endeavour to link atmospheric abundance ratios, such as the carbon-to-oxygen (C/O) ratio, to formation scenarios3. However, the complexity of planet formation requires further tracers, as the unambiguous interpretation of the measured C/O ratio is fraught with complexity4. Isotope ratios, such as deuterium to hydrogen and 14N/15N, offer a promising avenue to gain further insight into this formation process, mirroring their use within the Solar System5–7. For exoplanets, only a handful of constraints on 12C/13C exist, pointing to the accretion of 13C-rich ice from beyond the CO iceline of the disks8,9. Here we report on the mid-infrared detection of the 14NH3and 15NH3isotopologues in the atmosphere of a cool brown dwarf with an effective temperature of 380 K in a spectrum taken with the Mid-Infrared Instrument (MIRI) of JWST. As expected, our results reveal a 14N/15N value consistent with star-like formation by gravitational collapse, demonstrating that this ratio can be accurately constrained. Because young stars and their planets should be more strongly enriched in the 15N isotope10, we expect that 15NH3will be detectable in several cold, wide-separation exoplanets.

Published
2023
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22. Water in the terrestrial planet-forming zone of the PDS 70 disk

Author

Perotti, G., Christiaens, V., Henning, Th., Tabone, B., Waters, L. B. F. M., Kamp, I., Olofsson, G., Grant, S. L., Gasman, D., Bouwman, J., Samland, M., Franceschi, R., van Dishoeck, E. F., Schwarz, K., Güdel, M., Lagage, P.-O., Ray, T. P., Vandenbussche, B., Abergel, A., Absil, O., Arabhavi, A. M., Argyriou, I., Barrado, D., Boccaletti, A., Caratti o Garatti, A., Geers, V., Glauser, A. M., Justannont, K., Lahuis, F., Mueller, M., Nehmé, C., Pantin, E., Scheithauer, S., Waelkens, C., Guadarrama, R., Jang, H., Kanwar, J., Morales-Calderón, M., Pawellek, N., Rodgers-Lee, D., Schreiber, J., Colina, L., Greve, T. R., Östlin, G., and Wright, G.

Abstract

Terrestrial and sub-Neptune planets are expected to form in the inner (less than 10 au) regions of protoplanetary disks1. Water plays a key role in their formation2–4, although it is yet unclear whether water molecules are formed in situ or transported from the outer disk5,6. So far Spitzer Space Telescope observations have only provided water luminosity upper limits for dust-depleted inner disks7, similar to PDS 70, the first system with direct confirmation of protoplanet presence8,9. Here we report JWST observations of PDS 70, a benchmark target to search for water in a disk hosting a large (approximately 54 au) planet-carved gap separating an inner and outer disk10,11. Our findings show water in the inner disk of PDS 70. This implies that potential terrestrial planets forming therein have access to a water reservoir. The column densities of water vapour suggest in-situ formation via a reaction sequence involving O, H2and/or OH, and survival through water self-shielding5. This is also supported by the presence of CO2emission, another molecule sensitive to ultraviolet photodissociation. Dust shielding, and replenishment of both gas and small dust from the outer disk, may also play a role in sustaining the water reservoir12. Our observations also reveal a strong variability of the mid-infrared spectral energy distribution, pointing to a change of inner disk geometry.

Published
2023
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23. Verrucose liée aux papillomavirus humains de type β compliquant des districts cutanés immunodéprimés : caractéristiques cliniques, histologiques et virologiques d’une série de 11 patients

Author

Delahaye, T., Absil, G., and Nikkels, A.

Abstract

Les papillomavirus humains de type β (β-HPV) sont des constituants normaux du microbiome cutané. Exceptionnellement, ils peuvent entraîner une verrucose étendue sur la peau de patients gravement immunodéficients, comme dans le cas de l’épidermodysplasie verruciforme (EV) avec mutation EVER.

Published
2024
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24. Design of SCALES: a 2-5 micron coronagraphic integral field spectrograph for Keck Observatory

Author

Evans, Christopher J., Bryant, Julia J., Motohara, Kentaro, Skemer, Andrew J., Stelter, R. Deno, Sallum, Stephanie, MacDonald, Nicholas, Kupke, Renate, Ratliff, Christopher, Banyal, Ravinder, Hasan, Amirul, Varshney, Hari Mohan, Surya, Arun, Prakaesh, Ajin, Thirupathi, Sivarani, Sethuram, Ramya, K.V., Govinda, Fitzgerald, Michael P., Wang, Eric, Kassis, Marc, Absil, Olivier, Alvarez, Carlos, Batalha, Natasha, Boucher, Marc-André, Bourgenot, Cyril, Brandt, Timothy, Briesemeister, Zackery, de Kleer, Katherine, de Pater, Imke, Deich, William, Divakar, Devika, Filion, Guillaume, Gauvin, Étienne, Gonzales, Michael, Greene, Thomas, Hinz, Philip, Jensen-Clem, Rebecca, Johnson, Christopher, Kain, Isabel, Kruglikov, Gabriel, Lach, Mackenzie, Landry, Jean-Thomas, Li, Jialin, Liu, Michael C., Lyke, James, Magnone, Kenneth, Marin, Eduardo, Martin, Emily, Martinez, Raquel, Mawet, Dimitri, Miles, Brittany, Sandford, Dale, Sheehan, Patrick, Sohn, Ji Man, and Stone, Jordan

Published
2022
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26. First on-sky results of ERIS at VLT

Author

Evans, Christopher J., Bryant, Julia J., Motohara, Kentaro, Kravchenko, Kateryna, Dallilar, Yigit, Absil, Olivier, Berbel, Alex Agudo, Baruffolo, Andrea, Bonse, Markus, Buron, Alexander, Cao, Yixian, Cortes, Angela, Dannert, Felix, Davies, Richard, De Rosa, Robert J., Deysenroth, Matthias, Doelman, David S., Eisenhauer, Frank, Esposito, Simone, Feuchtgruber, Helmut, Förster Schreiber, Natascha, Gao, Xiaofeng, Gemperlein, Hans, Genzel, Reinhard, Gillessen, Stefan, Ginski, Christian, Glauser, Adrian, Glindemann, Andreas, Grani, Paolo, Haguenauer, Pierre, Hartwig, Johannes, Hayoz, Jean, Heida, Marianne, Kenworthy, Matthew, Kolb, Johann, Kuntschner, Harald, Lutz, Dieter, Liu, Daizhong, MacIntosh, Mike, Marsset, Michael, Orban de Xivry, Gilles, Özdemir, Hakan, Puglisi, Alfio, Quanz, Sascha, Rau, Christian, Riccardi, Armando, Schuppe, Daniel, Snik, Frans, Sturm, Eckhard, Tacconi, Linda, Taylor, William D., and Wiezorrek, Erich

Published
2022
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29. L-band nulling interferometry at the VLTI with Asgard/Hi-5: status and plans

Author

Mérand, Antoine, Sallum, Stephanie, Sanchez-Bermudez, Joel, Defrère, Denis, Bigioli, Azzurra, Dandumont, Colin, Garreau, Germain, Laugier, Romain, Martinod, Marc-Antoine, Absil, Olivier, Berger, Jean-Philippe, Bouzerand, Emilie, Courtney-Barrer, Benjamin, Emsenhuber, Alexandre, Ertel, Steve, Gagne, Jonathan, Glauser, Adrian, Gross, Simon, Ireland, Michael J., Kenchington, Harry-Dean, Kluska, Jacques, Kraus, Stefan, Labadie, Lucas, Laborde, Viktor, Léger, Alain, Leisenring, Jarron, Loicq, Jérôme, Martin, Guillermo, Morren, Johan, Matter, Alexis, Mazzoli, Alexandra, Missiaen, Kwinten, Muhammad, Salman, Ollivier, Marc, Raskin, Gert, Rousseau, Hélène, Sanny, Ahmed, Verlinden, Simon, Vandenbussche, Bart, and Woillez, Julien

Published
2022
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32. How to make METIS SCAO work

Author

Jackson, Kathryn J., Schmidt, Dirk, Vernet, Elise, Bertram, Thomas, Absil, Olivier, Bizenberger, Peter, Brandl, Bernhard, Brandner, Wolfgang, Briegel, Florian, Cárdenas Vázquez, María Concepción, Coppejans, Hugo, Correia, Carlos, Feldt, Markus, Häberle, Maximilian, Huber, Armin, Kulas, Martin, Laun, Werner, Mohr, Lars, Mortimer, Daniel, Naranjo, Vianak, Obereder, Andreas, Orban de Xivry, Gilles, Rohloff, Ralf-Rainer, Scheithauer, Silvia, Steuer, Horst, and van Boekel, Roy

Published
2024
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36. METIS high-contrast imaging: from final design to manufacturing and testing

Author

Bryant, Julia J., Motohara, Kentaro, Vernet, Joël R. D., Absil, Olivier, Kenworthy, Matthew, Delacroix, Christian, Orban de Xivry, Gilles, König, Lorenzo, Pathak, Prashant, Doelman, David, Por, Emiel, Snik, Frans, van den Born, Joost, Cantalloube, Faustine, Carlotti, Alexis, Courtney-Barrer, Benjamin, Forsberg, Pontus, Karlsson, Mikael, Bertram, Thomas, van Boekel, Roy, Dolkens, Dennis, Feldt, Markus, Glauser, Adrian M., Pantin, Eric, Quanz, Sascha P., Bettonvil, Felix, and Brandl, Bernhard

Published
2024
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37. SCALES status report

Author

Bryant, Julia J., Motohara, Kentaro, Vernet, Joël R. D., Stelter, R. Deno, Skemer, Andrew J., Sallum, Stephanie, MacDonald, Nick, Kupke, Renate, Ratliff, Christopher, Bourgenot, Cyril, Cabak, Gerald, Gonzales, Michael, Rodriguez, Cristian A., Hunter, Aaron, Banyal, Ravinder, Sivarani, Thirupathi, Fitzgerald, Michael P., Kassis, Marc, Absil, Olivier, Alvarez, Carlos, Batalha, Natatsha, Boucher, Marc-André, Brandt, Timothy, Briesemeister, Zack, de Kleer, Katherine, de Pater, Imke, Deich, William, Dicakar, Devika, Gauvin, Étienne, Greene, Thomas, Hasan, Armirul, Hinz, Philip, Jensen-Clem, Rebecca, Johnson, Christopher, K. V., Govinda, Kain, Isabel, Lach, Mackenzie, Landry, Jean-Thomas, Liu, Michael C., Lyke, Jim, Magone, Kenneth, Marin, Eduardo, Martinez, Raquel A., Mawet, Dimitri, McGurk, Rosalie, Miles, Brittany, Parkash, Ajin, Sandford, Dale, Sethuram, Ramya, Sheehan, Patrick, Sohn, Ji Man, Stone, Jordan, Surya, Arun, Varshney, Hari, and Wang, Eric

Published
2024
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38. Final design and status of the Mid-IR ELT Imager and Spectrograph, METIS

Author

Bryant, Julia J., Motohara, Kentaro, Vernet, Joël R. D., Brandl, Bernhard R., Bettonvil, Felix, van Boekel, Roy, Glauser, Adrian, Quanz, Sascha P., Absil, Olivier, Feldt, Markus, Garcia, Paulo J. V., Glasse, Alistair, Guedel, Manuel, Labadie, Lucas, Meyer, Michael, Pantin, Eric, Wang, Shiang-Yu, and van Winckel, Hans

Published
2024
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39. Low-rank multi-parametric covariance identification

Author

Musolas, Antoni, Massart, Estelle, Hendrickx, Julien M., Absil, P.-A., and Marzouk, Youssef

Abstract

We propose a differential geometric approach for building families of low-rank covariance matrices, via interpolation on low-rank matrix manifolds. In contrast with standard parametric covariance classes, these families offer significant flexibility for problem-specific tailoring via the choice of “anchor” matrices for interpolation, for instance over a grid of relevant conditions describing the underlying stochastic process. The interpolation is computationally tractable in high dimensions, as it only involves manipulations of low-rank matrix factors. We also consider the problem of covariance identification, i.e., selecting the most representative member of the covariance family given a data set. In this setting, standard procedures such as maximum likelihood estimation are nontrivial because the covariance family is rank-deficient; we resolve this issue by casting the identification problem as distance minimization. We demonstrate the utility of these differential geometric families for interpolation and identification in a practical application: wind field covariance approximation for unmanned aerial vehicle navigation.

Published
2022
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40. Optimization flows landing on the Stiefel manifold⋆

Author

Gao, Bin, Vary, Simon, Ablin, Pierre, and Absil, P.-A.

Abstract

We study a continuous-time system that solves optimization problems over the set of orthonormal matrices, which is also known as the Stiefel manifold. The resulting optimization flow follows a path that is not always on the manifold but asymptotically lands on the manifold. We introduce a generalized Stiefel manifold to which we extend the canonical metric of the Stiefel manifold. We show that the vector field of the proposed flow can be interpreted as the sum of a Riemannian gradient on a generalized Stiefel manifold and a normal vector. Moreover, we prove that the proposed flow globally converges to the set of critical points, and any local minimum and isolated critical point is asymptotically stable.

Published
2022
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41. Laparoscopic transperitoneal pudendal nerve and artery release for pudendal entrapment syndrome

Author

Bollens, Renaud, Mjaess, Georges, Sarkis, Julien, Chemaly, Anthony Kallas, Nemr, Elie, Daher, Karim, Semaan, Albert, Chebel, Josselin Abi, Absil, Fabienne, and Aoun, Fouad

Abstract

Introduction: Pudendal nerve and artery entrapment is an underdiagnosed pathology responsible of several urinary, sexual and anorectal complaints. The aim of our study was to evaluate safety and feasibility of laparoscopic transperitoneal pudendal nerve and artery release in a large retrospective cohort of patients with pudendal nerve entrapment syndrome with both a short and long-term follow-up. Technical details and outcomes are also reported. Methods: A series of 235 patients with pudendal syndrome underwent laparoscopic transperitoneal pudendal canal release between June 2015 and February 2020. Operative data were recorded prospectively for all patients. A complete history, pain visual analog scale (VAS) for perineodynia, and three scores evaluating the main symptoms (USP, IIEF-5, PAC-SYM) were obtained before and at least 24 months after surgery for 32 patients only. Post-operative complications were also evaluated using Clavien-Dindo classification at regular interval. Results: The mean operating time per side was 33.9 ± 6.8 min and the average hospital stay was 1.9 ± 0.3 days. Blood loss was 20 cc ± 10 cc with no patients needing transfusion. The only significant per-operative complication was hemorrhage (600 ml) in one patient induced by a pudendal artery laceration, successfully treated by laparoscopic suturing. Post-operative complications were noted in 18.7% of patients with no serious Clavien-Dindo complications. Perineodynia VAS dropped from 6.8 ± 0.9 to 2.2 ± 1.8 after surgery (p< 0.001). Mean IIEF-5 scores significantly improved one month after the surgery (15.2 vs 19.3, p= 0.036). Mean USP scores significantly improved for the dysuria domain (4.2 vs 1.6, p= 0.021) but not for stress urinary incontinence (3.9 vs 4.1, p= 0.082) or overactive bladder symptoms (14.1 vs 13.8, p= 0.079). Mean PAC-SYM scores significantly improved after the procedure (1.8 vs 1.1, p< 0.001). Conclusion: A complete laparoscopic pudendal nerve and artery release, from the sciatic spine through the Alcock’s canal, is a fast and safe surgery with promising functional results. A large prospective trial is needed to validate such an approach.

Published
2021
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44. Analyses of DNA Methylation Profiling in the Diagnosis of Intramedullary Astrocytomas

Author

Lebrun, Laetitia, Bizet, Martin, Melendez, Barbara, Alexiou, Barbara, Absil, Lara, Van Campenhout, Claude, D’Haene, Nicky, Rorive, Sandrine, Fuks, François, Decaestecker, Christine, and Salmon, Isabelle

Abstract

Intramedullary astrocytomas (IMAs) consist of a heterogeneous group of rare central nervous system (CNS) tumors associated with variable outcomes. A DNA methylation-based classification approach has recently emerged as a powerful tool to further classify CNS tumors. However, no DNA methylation-related studies specifically addressing to IMAs have been performed yet. In the present study, we analyzed 16 IMA samples subjected to morphological and molecular analyses, including DNA methylation profiling. Among the 16 samples, only 3 cases were classified in a reference methylation class (MC) with the recommended calibrated score (≥0.9). The remaining cases were either considered “no-match” cases (calibrated score <0.3, n = 7) or were classified with low calibrated scores (ranging from 0.32 to 0.53, n = 6), including inconsistent classification. To obtain a more comprehensive tool for pathologists, we used different unsupervised analyses of DNA methylation profiles, including our data and those from the Heidelberg reference cohort. Even though our cohort included only 16 cases, hypotheses regarding IMA-specific classification were underlined; a potential specific MC of PA_SPINE was identified and high-grade IMAs, probably consisting of H3K27M wild-type IMAs, were mainly associated with ANA_PA MC. These hypotheses strongly suggest that a specific classification for IMAs has to be investigated.

Published
2021
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45. Vector-apodizing phase plate coronagraph: design, current performance, and future development [Invited]

Author

Doelman, D. S., Snik, F., Por, E. H., Bos, S. P., Otten, G. P. P. L., Kenworthy, M., Haffert, S. Y., Wilby, M., Bohn, A. J., Sutlieff, B. J., Miller, K., Ouellet, M., de Boer, J., Keller, C. U., Escuti, M. J., Shi, S., Warriner, N. Z., Hornburg, K., Birkby, J. L., Males, J., Morzinski, K. M., Close, L. M., Codona, J., Long, J., Schatz, L., Lumbres, J., Rodack, A., Van Gorkom, K., Hedglen, A., Guyon, O., Lozi, J., Groff, T., Chilcote, J., Jovanovic, N., Thibault, S., de Jonge, C., Allain, G., Vallée, C., Patel, D., Côté, O., Marois, C., Hinz, P., Stone, J., Skemer, A., Briesemeister, Z., Boehle, A., Glauser, A. M., Taylor, W., Baudoz, P., Huby, E., Absil, O., Carlomagno, B., and Delacroix, C.

Abstract

Over the last decade, the vector-apodizing phase plate (vAPP) coronagraph has been developed from concept to on-sky application in many high-contrast imaging systems on 8 m class telescopes. The vAPP is a geometric-phase patterned coronagraph that is inherently broadband, and its manufacturing is enabled only by direct-write technology for liquid-crystal patterns. The vAPP generates two coronagraphic point spread functions (PSFs) that cancel starlight on opposite sides of the PSF and have opposite circular polarization states. The efficiency, that is, the amount of light in these PSFs, depends on the retardance offset from a half-wave of the liquid-crystal retarder. Using different liquid-crystal recipes to tune the retardance, different vAPPs operate with high efficiencies (${\gt}96\%$) in the visible and thermal infrared (0.55 µm to 5 µm). Since 2015, seven vAPPs have been installed in a total of six different instruments, including Magellan/MagAO, Magellan/MagAO-X, Subaru/SCExAO, and LBT/LMIRcam. Using two integral field spectrographs installed on the latter two instruments, these vAPPs can provide low-resolution spectra (${\rm{R}} \sim 30$) between 1 µm and 5 µm. We review the design process, development, commissioning, on-sky performance, and first scientific results of all commissioned vAPPs. We report on the lessons learned and conclude with perspectives for future developments and applications.

Published
2021

46. A rank estimation method for third-order tensor completion in the tensor-train format

Author

Vermeylen, Charlotte, Olikier, Guillaume, Absil, Pierre-Antoine, and Van Barel, Marc

Abstract

A numerical method to obtain an adequate value for the upper bound on the rank for the tensor completion problem on the variety of third-order tensors of bounded tensor-train rank is proposed. The method is inspired by the parametrization of the tangent cone derived by Kutschan (2018). The adequacy of the upper bound for a related low-rank tensor approximation problem is shown and an estimated rank is defined to extend the result to the low-rank tensor completion problem. Some experiments on synthetic data are given to illustrate the approach and show that the method is robust, e.g., to noise on the data.

Published
2024
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47. MINDS: The JWST MIRI Mid-INfrared Disk Survey

Author

Henning, Thomas, Kamp, Inga, Samland, Matthias, Arabhavi, Aditya M., Kanwar, Jayatee, van Dishoeck, Ewine F., Güdel, Manuel, Lagage, Pierre-Olivier, Waelkens, Christoffel, Abergel, Alain, Absil, Olivier, Barrado, David, Boccaletti, Anthony, Bouwman, Jeroen, Caratti o Garatti, Alessio, Geers, Vincent, Glauser, Adrian M., Lahuis, Fred, Mueller, Michael, Nehmé, Cyrine, Olofsson, Göran, Pantin, Eric, Ray, Tom P., Scheithauer, Silvia, Vandenbussche, Bart, Waters, L. B. F. M., Wright, Gillian, Argyriou, Ioannis, Christiaens, Valentin, Franceschi, Riccardo, Gasman, Danny, Grant, Sierra L., Guadarrama, Rodrigo, Jang, Hyerin, Morales-Calderón, Maria, Pawellek, Nicole, Perotti, Giulia, Rodgers-Lee, Donna, Schreiber, Jürgen, Schwarz, Kamber, Tabone, Benoît, Temmink, Milou, Vlasblom, Marissa, Colina, Luis, Greve, Thomas R., and Östlin, Göran

Abstract

The study of protoplanetary disks has become increasingly important with the Kepler satellite finding that exoplanets are ubiquitous around stars in our galaxy and the discovery of enormous diversity in planetary system architectures and planet properties. High-resolution near-IR and ALMA images show strong evidence for ongoing planet formation in young disks. The JWST MIRI mid-INfrared Disk Survey (MINDS) aims to (1) investigate the chemical inventory in the terrestrial planet-forming zone across stellar spectral type, (2) follow the gas evolution into the disk dispersal stage, and (3) study the structure of protoplanetary and debris disks in the thermal mid-IR. The MINDS survey will thus build a bridge between the chemical inventory of disks and the properties of exoplanets. The survey comprises 52 targets (Herbig Ae stars, T Tauri stars, very low-mass stars and young debris disks). We primarily obtain MIRI/MRS spectra with high signal-to-noise ratio (∼100–500) covering the complete wavelength range from 4.9 to 27.9 μm. For a handful of selected targets we also obtain NIRSpec IFU high resolution spectroscopy (2.87–5.27 μm). We will search for signposts of planet formation in thermal emission of micron-sized dust—information complementary to near-IR scattered light emission from small dust grains and emission from large dust in the submillimeter wavelength domain. We will also study the spatial structure of disks in three key systems that have shown signposts for planet formation, TW Hya and HD 169142 using the MIRI coronagraph at 15.5 μm and 10.65 μm respectively and PDS 70 using NIRCam imaging in the 1.87 μm narrow and the 4.8 μm medium band filter. We provide here an overview of the MINDS survey and showcase the power of the new JWST mid-IR molecular spectroscopy with the TW Hya disk spectrum where we report the detection of the molecular ion CH3+and the robust confirmation of HCO+earlier detected with Spitzer.

Published
2024
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48. Laparoscopic treatment of pudendal nerve and artery entrapment improves erectile dysfunction in healthy young males

Author

Aoun, Fouad, Mjaess, Georges, Daher, Karim, Sakr, Ghazi, Chemaly, Anthony Kallas, Salameh, Mohammad, Albisinni, Simone, Absil, Fabienne, Roumeguere, Thierry, and Bollens, Renaud

Abstract

Erectile dysfunction (ED) is increasingly becoming more common in young healthy males and is attributed mainly to psychogenic causes in these patients. Recent studies have reported that ED could be secondary to pudendal nerve or artery entrapment. This perspective assessed the efficacy of laparoscopic pudendal nerve and artery decompression in young patients suffering from refractory ED, associated to a pudendal nerve entrapment syndrome. After excluding patients with psychological ED and venous leakage, five young male patients with a history of both ED and pudendal nerve entrapment syndrome diagnosed based on the Nantes criteria were recruited. Pudendal nerve and artery release was performed using a laparoscopic transperitoneal approach. International Index for Erectile Function (IIEF-5) and erectile hardness score (EHS) improved significantly in all patients, 3 months after surgery. Pudendal nerve and artery entrapment could be therefore a reversible cause of ED in young healthy males, and its treatment by laparoscopic pudendal nerve and artery decompression seems to be safe and effective.

Published
2021
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49. Is pudendal nerve entrapment a potential cause for weak ejaculation?

Author

Aoun, Fouad, Mjaess, Georges, Lilly, Eddy, Khalil, Nour, Tayeh, Georges Abi, Sarkis, Julien, Mansour, Raymond, Alkassis, Marwan, Chebel, Roy, Absil, Fabienne, and Bollens, Renaud

Abstract

Ejaculatory dysfunction is one of the most common complaints of patients with sexual disorders. While it encompasses several ejaculatory disorders, weak ejaculation is seldom described in the literature. Since the pudendal nerve is the main nerve of ejaculation, we aim to hypothesize that pudendal nerve entrapment could be a cause of weak ejaculation, and that pudendal nerve release could contribute to the improvement of the ejaculatory stream. We presented two cases suffering from a weak ejaculatory stream and sensation of incomplete semen emptying, accompanied with clinical features of pudendal nerve entrapment. Both cases improved after pudendal nerve block and then laparoscopic transperitoneal pudendal release, with a sustained amelioration of the ejaculatory stream after 3 weeks of surgery. Pudendal canal entrapment is therefore a potentially curable cause for weak ejaculation.

Published
2021
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50. Review and scientific prospects of high-contrast optical stellar interferometry

Author

Tuthill, Peter G., Mérand, Antoine, Sallum, Stephanie, Defrère, D., Absil, O., Berger, J.-P., Danchi, W. C., Dandumont, C., Eisenhauer, F., Ertel, S., Gardner, T., Glauser, A., Hinz, P., Ireland, M., Kammerer, J., Kraus, S., Labadie, L., Lacour, S., Laugier, R., Loicq, J., Martin, G., Martinache, F., Martinod, M. A., Mennesson, B., Monnier, J., Norris, B., Nowak, M., Pott, J. U., Quanz, S. P., Serabyn, E., Stone, J., Tuthill, P., and Woillez, J.

Published
2020
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