161,049 results on '"Ziegler A"'
Search Results
2. Quantum Hall effect and current distribution in the 3D topological insulator HgTe
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Hartl, S., Freund, L., Kühn, M., Ziegler, J., Richter, E., Himmler, W., Bärenfänger, J., Kozlov, D. A., Mikhailov, N. N., Weis, J., and Weiss, D.
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Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We study the quantum Hall effect (QHE) in the three-dimensional topological insulator HgTe, which features topological Dirac-type surface states in a bulk gap opened by strain. Despite the co-existence of multiple carrier subsystems, the system exhibits perfectly quantized Hall plateaus at high magnetic fields. Here we study the system using three different experimental techniques: Transport experiments, capacitance measurements including the quantum capacitance, and current distribution measurements using electrostatically sensitive scanning probe microscopy. Our key finding is that at sufficiently high magnetic fields, the different electronic subsystems merge into one, and the current in a quantum Hall plateau is distributed across the entire width of the Hall bar device., Comment: 9 pages, 9 figures. Submitted to PRR
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- 2024
3. 12-spin-qubit arrays fabricated on a 300 mm semiconductor manufacturing line
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George, Hubert C., Mądzik, Mateusz T., Henry, Eric M., Wagner, Andrew J., Islam, Mohammad M., Borjans, Felix, Connors, Elliot J., Corrigan, Joelle, Curry, Matthew, Harper, Michael K., Keith, Daniel, Lampert, Lester, Luthi, Florian, Mohiyaddin, Fahd A., Murcia, Sandra, Nair, Rohit, Nahm, Rambert, Nethwewala, Aditi, Neyens, Samuel, Raharjo, Roy D., Rogan, Carly, Savytskyy, Rostyslav, Watson, Thomas F., Ziegler, Josh, Zietz, Otto K., Pillarisetty, Ravi, Bishop, Nathaniel C., Bojarski, Stephanie A., Roberts, Jeanette, and Clarke, James S.
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Condensed Matter - Mesoscale and Nanoscale Physics ,Quantum Physics - Abstract
Intels efforts to build a practical quantum computer are focused on developing a scalable spin-qubit platform leveraging industrial high-volume semiconductor manufacturing expertise and 300 mm fabrication infrastructure. Here, we provide an overview of the design, fabrication, and demonstration of a new customized quantum test chip, which contains 12-quantum-dot spin-qubit linear arrays, code named Tunnel Falls. These devices are fabricated using immersion and extreme ultraviolet lithography (EUV), along with other standard high-volume manufacturing (HVM) processes, as well as production-level process control. We present key device features and fabrication details, as well as qubit characterization results confirming device functionality. These results corroborate our fabrication methods and are a crucial step towards scaling of extensible 2D qubit array schemes.
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- 2024
4. TEXEL: A neuromorphic processor with on-chip learning for beyond-CMOS device integration
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Greatorex, Hugh, Richter, Ole, Mastella, Michele, Cotteret, Madison, Klein, Philipp, Fabre, Maxime, Rubino, Arianna, Girão, Willian Soares, Chen, Junren, Ziegler, Martin, Bégon-Lours, Laura, Indiveri, Giacomo, and Chicca, Elisabetta
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Computer Science - Neural and Evolutionary Computing ,Computer Science - Hardware Architecture ,Computer Science - Emerging Technologies ,Computer Science - Machine Learning - Abstract
Recent advances in memory technologies, devices and materials have shown great potential for integration into neuromorphic electronic systems. However, a significant gap remains between the development of these materials and the realization of large-scale, fully functional systems. One key challenge is determining which devices and materials are best suited for specific functions and how they can be paired with CMOS circuitry. To address this, we introduce TEXEL, a mixed-signal neuromorphic architecture designed to explore the integration of on-chip learning circuits and novel two- and three-terminal devices. TEXEL serves as an accessible platform to bridge the gap between CMOS-based neuromorphic computation and the latest advancements in emerging devices. In this paper, we demonstrate the readiness of TEXEL for device integration through comprehensive chip measurements and simulations. TEXEL provides a practical system for testing bio-inspired learning algorithms alongside emerging devices, establishing a tangible link between brain-inspired computation and cutting-edge device research., Comment: 17 pages, 7 figures. Supplementary material: 8 pages, 4 figures
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- 2024
5. TESS Hunt for Young and Maturing Exoplanets (THYME) XII: A Young Mini-Neptune on the Upper Edge of the Radius Valley in the Hyades Cluster
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Distler, Adam, Soares-Furtado, Melinda, Vanderburg, Andrew, Schulte, Jack, Becker, Juliette, Mann, Andrew W., Howell, Steve B., Kraus, Adam L., Barkaoui, Khalid, Briceño, César, Collins, Karen A., Conti, Dennis, Jenkins, Jon M., Limbach, Mary Anne, Quinn, Samuel N., Turner, Jake D., Twicken, Joseph D., Schwarz, Richard P., Seager, Sara, Winn, Joshua N., and Ziegler, Carl
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Astrophysics - Earth and Planetary Astrophysics - Abstract
We present the discovery and characterization of TOI-4364\,b, a young mini-Neptune in the tidal tails of the Hyades cluster, identified through TESS transit observations and ground-based follow-up photometry. The planet orbits a bright M dwarf ($K=9.1$\,mag) at a distance of 44\,pc, with an orbital period of 5.42\,days and an equilibrium temperature of $488^{+4}_{-4}$\,K. The host star's well-constrained age of 710\,Myr makes TOI-4364\,b an exceptional target for studying early planetary evolution around low-mass stars. We determined a planetary radius of $2.01^{+0.1}_{-0.08}$\,Earth radii, indicating that this planet is situated near the upper edge of the radius valley. This suggests that the planet retains a modest H/He envelope. As a result, TOI-4364\,b provides a unique opportunity to explore the transition between rocky super-Earths and gas-rich mini-Neptunes at the early stages of evolution. Its radius, which may still evolve as a result of ongoing atmospheric cooling, contraction, and photoevaporation, further enhances its significance for understanding planetary development. Furthermore, TOI-4364\,b possesses a moderately high Transmission Spectroscopy Metric of 44.2, positioning it as a viable candidate for atmospheric characterization with instruments such as JWST. This target has the potential to offer crucial insights into atmospheric retention and loss in young planetary systems., Comment: 18 pages, 9 figures
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- 2024
6. Asymmetrically connected reservoir networks learn better
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Rathor, Shailendra K., Ziegler, Martin, and Schumacher, Jörg
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Computer Science - Neural and Evolutionary Computing ,Nonlinear Sciences - Chaotic Dynamics - Abstract
We show that connectivity within the high-dimensional recurrent layer of a reservoir network is crucial for its performance. To this end, we systematically investigate the impact of network connectivity on its performance, i.e., we examine the symmetry and structure of the reservoir in relation to its computational power. Reservoirs with random and asymmetric connections are found to perform better for an exemplary Mackey-Glass time series than all structured reservoirs, including biologically inspired connectivities, such as small-world topologies. This result is quantified by the information processing capacity of the different network topologies which becomes highest for asymmetric and randomly connected networks., Comment: 6 pages, 4 figures, supplementary material
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- 2024
7. TOI-2458 b: A mini-Neptune consistent with in situ hot Jupiter formation
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Šubjak, Ján, Gandolfi, Davide, Goffo, Elisa, Rapetti, David, Nowak, Grzegorz, Mizuki, Toshiyuki, Dai, Fei, Serrano, Luisa M., Wilson, Thomas G., Jankowski, Dawid, Goździewski, Krzysztof, Jenkins, Jon M., Twicken, Joseph D., Winn, Joshua N., Bieryla, Allyson, Cochran, William D., Collins, Karen A., Deeg, Hans J., García, Rafael A., Guenther, Eike W., Hatzes, Artie P., Kabáth, Petr, Korth, Judith, Latham, David W., Livingston, John H., Mathur, Savita, Narita, Norio, Orell-Miquel, Jaume, Pallé, Enric, Persson, Carina M., Redfield, Seth, Schwarz, Richard P., Watanabe, David, and Ziegler, Carl
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Astrophysics - Earth and Planetary Astrophysics - Abstract
We report on the discovery and spectroscopic confirmation of TOI-2458 b, a transiting mini-Neptune around an F-type star leaving the main-sequence with a mass of $M_\star=1.05 \pm 0.03$ M$_{\odot}$, a radius of $R_\star=1.31 \pm 0.03$ R$_{\odot}$, an effective temperature of $T_{\rm eff}=6005\pm50$ K, and a metallicity of $-0.10\pm0.05$ dex. By combining TESS photometry with high-resolution spectra acquired with the HARPS spectrograph, we found that the transiting planet has an orbital period of $\sim$3.74 days, a mass of $M_p=13.31\pm0.99$ M$_{\oplus}$ and a radius of $R_p=2.83\pm0.20$ R$_{\oplus}$. The host star TOI-2458 shows a short activity cycle of $\sim$54 days revealed in the HARPS S-index time series. We took the opportunity to investigate other F stars showing activity cycle periods comparable to that of TOI-2458 and found that they have shorter rotation periods than would be expected based on the gyrochronology predictions. In addition, we determined TOI-2458's stellar inclination angle to be $i_\star\,=\,10.6_{-10.6}^{+13.3}$ degrees. We discuss that both phenomena (fast stellar rotation and planet orbit inclination) could be explained by in situ formation of a hot Jupiter interior to TOI-2458 b. It is plausible that this hot Jupiter was recently engulfed by the star. Analysis of HARPS spectra has identified the presence of another planet with a period of $P\,=\,16.55\pm0.06$ days and a minimum mass of $M_p \sin i=10.22\pm1.90$ M$_{\oplus}$., Comment: 22 pages, 17 figures, submitted to Astronomy & Astrophysics
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- 2024
8. TOI-5005 b: A super-Neptune in the savanna near the ridge
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Castro-González, A., Lillo-Box, J., Armstrong, D. J., Acuña, L., Aguichine, A., Bourrier, V., Gandhi, S., Sousa, S. G., Delgado-Mena, E., Moya, A., Adibekyan, V., Correia, A. C. M., Barrado, D., Damasso, M., Winn, J. N., Santos, N. C., Barkaoui, K., Barros, S. C. C., Benkhaldoun, Z., Bouchy, F., Briceño, C., Caldwell, D. A., Collins, K. A., Essack, Z., Ghachoui, M., Gillon, M., Hounsell, R., Jehin, E., Jenkins, J. M., Keniger, M. A. F., Law, N., Mann, A. W., Nielsen, L. D., Pozuelos, F. J., Schanche, N., Seager, S., Tan, T. -G., Timmermans, M., Villaseñor, J., Watkins, C. N., and Ziegler, C.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
The Neptunian desert and savanna have been recently found to be separated by a ridge, an overdensity of planets in the $\simeq$3-5 days period range. These features are thought to be shaped by dynamical and atmospheric processes. However, their relative roles are not yet well understood. We intend to confirm and characterise the super-Neptune TESS candidate TOI-5005.01, which orbits a moderately bright (V = 11.8) solar-type star (G2 V) with an orbital period of 6.3 days. We confirm TOI-5005 b to be a transiting super-Neptune with a radius of $R_{\rm p}$ = $6.25\pm 0.24$ $\rm R_{\rm \oplus}$ ($R_{\rm p}$ = $0.558\pm 0.021$ $\rm R_{\rm J}$) and a mass of $M_{\rm p}$ = $32.7\pm 5.9$ $\rm M_{\oplus}$ ($M_{\rm p}$ = $0.103\pm 0.018$ $\rm M_{\rm J}$), which corresponds to a mean density of $\rho_{\rm p}$ = $0.74 \pm 0.16$ $\rm g \, cm^{-3}$. Our internal structure modelling indicates that the overall metal mass fraction is well constrained to a value slightly lower than that of Neptune and Uranus ($Z_{\rm planet}$ = $0.76^{+0.04}_{-0.11}$). We also estimated the present-day atmospheric mass-loss rate of TOI-5005 b but found contrasting predictions depending on the choice of photoevaporation model. At a population level, we find statistical evidence ($p$-value = $0.0092^{+0.0184}_{-0.0066}$) that planets in the savanna such as TOI-5005 b tend to show lower densities than planets in the ridge, with a dividing line around 1 $\rm g \, cm^{-3}$, which supports the hypothesis of different evolutionary pathways populating both regimes. TOI-5005 b is located in a key region of the period-radius space to study the transition between the Neptunian ridge and the savanna. It orbits the brightest star of all such planets, which makes it a target of interest for atmospheric and orbital architecture observations that will bring a clearer picture of its overall evolution., Comment: Accepted for publication in A&A. Abstract shortened. 35 pages, 26 figures
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- 2024
9. Twisted points of quotient stacks, integration and BPS-invariants
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Groechenig, Michael, Wyss, Dimitri, and Ziegler, Paul
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Mathematics - Algebraic Geometry - Abstract
We study $p$-adic manifolds associated with twisted points of quotient stacks $\mathcal{X} = [U/G]$ and their quotient spaces $\pi:\mathcal{X} \to X$. We prove several structural results about the fibres of $\pi$ and derive in particular a formula expressing $p$-adic integrals on $X$ in terms of the cyclotomic inertia stack of $\mathcal{X}$, generalizing the orbifold formula for Deligne-Mumford stacks. We then apply our formalism to moduli stacks of $1$-dimensional sheaves on del Pezzo surfaces and show that their refined BPS-invariants are computed locally on the coarse moduli space by a $p$-adic integral. As a consequence we recover the $\chi$-independence of these invariants previously proven by Maulik-Shen. Along the way we derive a new formula for the plethystic logarithm on the $\lambda$-ring of functions on $k$-linear stacks, which might be of independent interest., Comment: 34 pages. Comments welcome!
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- 2024
10. Spin Detection Using Racket Bounce Sounds in Table Tennis
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Gossard, Thomas, Schmalzl, Julian, Ziegler, Andreas, and Zell, Andreas
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Computer Science - Sound ,Electrical Engineering and Systems Science - Audio and Speech Processing - Abstract
While table tennis players primarily rely on visual cues, sound provides valuable information. The sound generated when the ball strikes the racket can assist in predicting the ball's trajectory, especially in determining the spin. While professional players can distinguish spin through these auditory cues, they often go unnoticed by untrained players. In this paper, we demonstrate that different rackets produce distinct sounds, which can be used to identify the racket type. In addition, we show that the sound generated by the racket can indicate whether spin was applied to the ball, or not. To achieve this, we created a comprehensive dataset featuring bounce sounds from 10 racket configurations, each applying various spins to the ball. To achieve millisecond level temporal accuracy, we first detect high frequency peaks that may correspond to table tennis ball bounces. We then refine these results using a CNN based classifier that accurately predicts both the type of racket used and whether spin was applied., Comment: Submitted to ICASSP 2025
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- 2024
11. Validation of up to seven TESS planet candidates through multi-colour transit photometry using MuSCAT2 data
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Peláez-Torres, A., Esparza-Borges, E., Pallé, E., Parviainen, H., Murgas, F., Morello, G., Zapatero-Osorio, M. R., Korth, J., Narita, N., Fukui, A., Carleo, I., Luque, R., García, N. Abreu, Barkaoui, K., Boyle, A., Béjar, V. J. S., Calatayud-Borras, Y., Cheryasov, D. V., Christiansen, J. L., Ciardi, D. R., Enoc, G., Essack, Z., Fukuda, I., Furesz, G., Galán, D., Geraldía-González, S., Giacalone, S., Gill, H., Gonzales, E. J., Hayashi, Y., Ikuta, K., Isogai, K., Kagetani, T., Kawai, Y., Kawauchi, K., Klagyvik, P., Kodama, T., Kusakabe, N., Laza-Ramos, A., de Leon, J. P., Livingston, J. H., Lund, M. B., Madrigal-Aguado, A., Meni, P., Mori, M., Torres, S. Muñoz, Orell-Miquel, J., Puig, M., Ricker, G., Sánchez-Benavente, M., Savel, A. B., Schlieder, J. E., Schwarz, R. P., Sefako, R., Sosa-Guillén, P., Stangret, M., Stockdale, C., Tamura, M., Terada, Y., Twicken, J. D., Watanabe, N., Winn, J., Zheltoukhov, S. G., Ziegler, C., and Zou, Y.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
The TESS mission searches for transiting exoplanets by monitoring the brightness of hundreds of thousands of stars across the entire sky. M-type planet hosts are ideal targets for this mission due to their smaller size and cooler temperatures, which makes it easier to detect smaller planets near or within their habitable zones. Additionally, M~dwarfs have a smaller contrast ratio between the planet and the star, making it easier to measure the planet's properties accurately. Here, we report the validation analysis of 13 TESS exoplanet candidates orbiting around M dwarfs. We studied the nature of these candidates through a multi-colour transit photometry transit analysis using several ground-based instruments (MuSCAT2, MuSCAT3, and LCO-SINISTRO), high-spatial resolution observations, and TESS light curves. We present the validation of five new planetary systems: TOI-1883b, TOI-2274b, TOI2768b, TOI-4438b, and TOI-5319b, along with compelling evidence of a planetary nature for TOIs 2781b and 5486b. We also present an empirical definition for the Neptune desert boundaries. The remaining six systems could not be validated due to large true radius values overlapping with the brown dwarf regime or, alternatively, the presence of chromaticity in the MuSCAT2 light curves.
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- 2024
12. CRAFT Your Dataset: Task-Specific Synthetic Dataset Generation Through Corpus Retrieval and Augmentation
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Ziegler, Ingo, Köksal, Abdullatif, Elliott, Desmond, and Schütze, Hinrich
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Computer Science - Computation and Language ,Computer Science - Artificial Intelligence ,Computer Science - Machine Learning - Abstract
Building high-quality datasets for specialized tasks is a time-consuming and resource-intensive process that often requires specialized domain knowledge. We propose Corpus Retrieval and Augmentation for Fine-Tuning (CRAFT), a method for generating synthetic datasets, given a small number of user-written few-shots that demonstrate the task to be performed. Given the few-shot examples, we use large-scale public web-crawled corpora and similarity-based document retrieval to find other relevant human-written documents. Lastly, instruction-tuned large language models (LLMs) augment the retrieved documents into custom-formatted task samples, which then can be used for fine-tuning. We demonstrate that CRAFT can efficiently generate large-scale task-specific training datasets for four diverse tasks: biology question-answering (QA), medicine QA and commonsense QA as well as summarization. Our experiments show that CRAFT-based models outperform or achieve comparable performance to general LLMs for QA tasks, while CRAFT-based summarization models outperform models trained on human-curated data by 46 preference points.
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- 2024
13. Disentangling Mean Embeddings for Better Diagnostics of Image Generators
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Gruber, Sebastian G., Ziegler, Pascal Tobias, and Buettner, Florian
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
The evaluation of image generators remains a challenge due to the limitations of traditional metrics in providing nuanced insights into specific image regions. This is a critical problem as not all regions of an image may be learned with similar ease. In this work, we propose a novel approach to disentangle the cosine similarity of mean embeddings into the product of cosine similarities for individual pixel clusters via central kernel alignment. Consequently, we can quantify the contribution of the cluster-wise performance to the overall image generation performance. We demonstrate how this enhances the explainability and the likelihood of identifying pixel regions of model misbehavior across various real-world use cases., Comment: Preprint
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- 2024
14. The Effects of Procedural and Conceptual Knowledge on Visual Learning
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Nadja Beeler, Esther Ziegler, Andreas Volz, Alexander A. Navarini, and Manu Kapur
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Even though past research suggests that visual learning may benefit from conceptual knowledge, current interventions for medical image evaluation often focus on procedural knowledge, mainly by teaching classification algorithms. We compared the efficacy of pure procedural knowledge (three-point checklist for evaluating skin lesions) versus combined procedural plus conceptual knowledge (histological explanations for each of the three points). All students then trained their classification skills with a visual learning resource that included images of two types of pigmented skin lesions: benign nevi and malignant melanomas. Both treatments produced significant and long-lasting effects on diagnostic accuracy in transfer tasks. However, only students in the combined procedural plus conceptual knowledge condition significantly improved their diagnostic performance in classifying lesions they had seen before in the pre- and post-tests. Findings suggest that the provision of additional conceptual knowledge supported error correction mechanisms.
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- 2024
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15. Ultra-rapid, Quantitative, Label-free Antibiotic Susceptibility Testing via Optically Detected Purine Metabolites
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Premasiri, Ranjith, Fraiman, Allen, and Ziegler, Lawrence
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Quantitative Biology - Subcellular Processes - Abstract
There is an urgent need for the development of novel and truly rapid (equal or less than 1 hour) antibiotic susceptibility testing (AST) platforms in order to provide best antimicrobial prescribing practices and to help reduce the increasing global threat of antibiotic resistance. A 785 nm surface enhanced Raman spectroscopy (SERS) based phenotypic methodology is described that results in accurate minimum inhibitory concentration (MIC) determinations for all tested strain-antibiotic pairs. The SERS-AST procedure results in accurate MICs, the key quantitative measure of in vitro drug susceptibility, in 1 hour, including a 30-minute incubation period. The method is effective for both Gram positive and negative species, and for antibiotics with different initial primary targets of antibiotic activity, and for both bactericidal and bacteriostatic antibiotics. The molecular level mechanism of this methodology is described. Bacterial SERS spectra are due to secreted purine nucleotide degradation products (principally adenine, guanine, xanthine and hypoxanthine) resulting from water washing induced bacterial stringent response and the resulting (p)ppGpp alarmone mediates nucleobase formation from unneeded tRNA and rRNA. The rewiring of metabolic responses resulting from the secondary metabolic effects of antibiotic exposure during the 30-minute incubation period accounts for the dose dependence of the SERS spectral intensities which are used to accurately yield the MIC. This is the fastest demonstrated AST method yielding MICs.
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- 2024
16. The MICADO first light imager for the ELT: overview and current Status
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Sturm, E., Davies, R., Alves, J., Clénet, Y., Kotilainen, J., Monna, A., Nicklas, H., Pott, J. -U., Tolstoy, E., Vulcani, B., Achren, J., Annadevara, S., Anwand-Heerwart, H., Arcidiacono, C., Barboza, S., Barl, L., Baudoz, P., Bender, R., Bezawada, N., Biondi, F., Bizenberger, P., Blin, A., Boné, A., Bonifacio, P., Borgo, B., Born, J. van den, Buey, T., Cao, Y., Chapron, F., Chauvin, G., Chemla, F., Cloiseau, K., Cohen, M., Collin, C., Czoske, O., Dette, J. -O., Deysenroth, M., Dijkstra, E., Dreizler, S., Dupuis, O., van Egmond, G., Eisenhauer, F., Elswijk, E., Emslander, A., Fabricius, M., Fasola, G., Ferreira, F., Schreiber, N. M. Förster, Fontana, A., Gaudemard, J., Gautherot, N., Gendron, E., Gennet, C., Genzel, R., Ghouchou, L., Gillessen, S., Gratadour, D., Grazian, A., Grupp, F., Guieu, S., Gullieuszik, M., de Haan, M., Hartke, J., Hartl, M., Haussmann, F., Helin, T., Hess, H. -J., Hofferbert, R., Huber, H., Huby, E., Huet, J. -M., Ives, D., Janssen, A., Jaufmann, P., Jilg, T., Jodlbauer, D., Jost, J., Kausch, W., Kellermann, H., Kerber, F., Kravcar, H., Kravchenko, K., Kulcsár, C., Kunkarayakti, H., Kunst, P., Kwast, S., Lang, F., Lange, J., Lapeyrere, V., Ruyet, B. Le, Leschinski, K., Locatelli, H., Massari, D., Mattila, S., Mei, S., Merlin, F., Meyer, E., Michel, C., Mohr, L., Montargès, M., Müller, F., Münch, N., Navarro, R., Neumann, U., Neumayer, N., Neumeier, L., Pedichini, F., Pflüger, A., Piazzesi, R., Pinard, L., Porras, J., Portaluri, E., Przybilla, N., Rabien, S., Raffard, J., Raggazoni, R., Ramlau, R., Ramos, J., Ramsay, S., Raynaud, H. -F., Rhode, P., Richter, A., Rix, H. -W., Rodenhuis, M., Rohloff, R. -R., Romp, R., Rousselot, P., Sabha, N., Sassolas, B., Schlichter, J., Schuil, M., Schweitzer, M., Seemann, U., Sevin, A., Simioni, M., Spallek, L., Sönmez, A., Suuronen, J., Taburet, S., Thomas, J., Tisserand, E., Vaccari, P., Valenti, E., Kleijn, G. Verdoes, Verdugo, M., Vidal, F., Wagner, R., Wegner, M., van Winden, D., Witschel, J., Zanella, A., Zeilinger, W., Ziegleder, J., and Ziegler, B.
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
MICADO is a first light instrument for the Extremely Large Telescope (ELT), set to start operating later this decade. It will provide diffraction limited imaging, astrometry, high contrast imaging, and long slit spectroscopy at near-infrared wavelengths. During the initial phase operations, adaptive optics (AO) correction will be provided by its own natural guide star wavefront sensor. In its final configuration, that AO system will be retained and complemented by the laser guide star multi-conjugate adaptive optics module MORFEO (formerly known as MAORY). Among many other things, MICADO will study exoplanets, distant galaxies and stars, and investigate black holes, such as Sagittarius A* at the centre of the Milky Way. After their final design phase, most components of MICADO have moved on to the manufacturing and assembly phase. Here we summarize the final design of the instrument and provide an overview about its current manufacturing status and the timeline. Some lessons learned from the final design review process will be presented in order to help future instrumentation projects to cope with the challenges arising from the substantial differences between projects for 8-10m class telescopes (e.g. ESO-VLT) and the next generation Extremely Large Telescopes (e.g. ESO-ELT). Finally, the expected performance will be discussed in the context of the current landscape of astronomical observatories and instruments. For instance, MICADO will have similar sensitivity as the James Webb Space Telescope (JWST), but with six times the spatial resolution., Comment: Proceedings of the SPIE, Volume 13096, id. 1309611 11 pp. (2024)
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- 2024
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17. Energy Relaxation of N$_2$O in Gaseous, Supercritical and Liquid Xenon and SF$_6$
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Töpfer, Kai, Erramilli, Shyamsunder, Ziegler, Lawrence D., and Meuwly, Markus
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Physics - Chemical Physics - Abstract
Rotational and vibrational energy relaxation (RER and VER) of N$_2$O embedded in xenon and SF$_6$ environments ranging from the gas phase to the liquid, including the supercritical regime, is studied at a molecular level. Calibrated intermolecular interactions from high-level electronic structure calculations, validated against experiments for the pure solvents were used to carry out classical molecular dynamics simulations corresponding to experimental state points for near-critical isotherms. Computed RER rates in low-density solvent of $k_{\rm rot}^{\rm Xe} = (3.67\pm0.25)\cdot10^{10}$ s$^{-1}$M$^{-1}$ and $k_{\rm rot}^{\rm SF_6} = (1.25\pm0.12)\cdot10^{11}$ s$^{-1}$M$^{-1}$ compare well with rates determined by analysis of 2-dimensional infrared experiments. Simulations find that an isolated binary collision (IBC) description is successful up to solvent concentrations of $\sim 4$ M. For higher densities, including the supercritical regime, the simulations do not correctly describe RER, probably due to neglect of solvent-solute coupling in the analysis of the rotational motion. For VER, the near-quantitative agreement between simulations and pump-probe experiments captures the solvent density-dependent trends.
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- 2024
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18. The MAGPI Survey: the evolution and drivers of gas turbulence in intermediate-redshift galaxies
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Mai, Yifan, Croom, Scott M., Wisnioski, Emily, Vaughan, Sam P., Varidel, Mathew R., Battisti, Andrew J., Mendel, J. Trevor, Mun, Marcie, Tsukui, Takafumi, Foster, Caroline, Harborne, Katherine E., Lagos, Claudia D. P., Wang, Di, Bellstedt, Sabine, Bland-Hawthorn, Joss, Colless, Matthew, D'Eugenio, Francesco, Grasha, Kathryn, Peng, Yingjie, Santucci, Giulia, Sweet, Sarah M., Thater, Sabine, Valenzuela, Lucas M., and Ziegler, Bodo
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Astrophysics - Astrophysics of Galaxies - Abstract
We measure the ionised gas velocity dispersions of star-forming galaxies in the MAGPI survey ($z\sim0.3$) and compare them with galaxies in the SAMI ($z\sim0.05$) and KROSS ($z\sim1$) surveys to investigate how the ionised gas velocity dispersion evolves. For the first time, we use a consistent method that forward models galaxy kinematics from $z=0$ to $z=1$. This method accounts for spatial substructure in emission line flux and beam smearing. We investigate the correlation between gas velocity dispersion and galaxy properties to understand the mechanisms that drive gas turbulence. We find that in both MAGPI and SAMI galaxies, the gas velocity dispersion more strongly correlates with the star-formation rate surface density ($\Sigma_{\rm SFR}$) than with a variety of other physical properties, and the average gas velocity dispersion is similar, at the same $\Sigma_{\rm SFR}$, for SAMI, MAGPI and KROSS galaxies. The results indicate that mechanisms related to $\Sigma_{\rm SFR}$ could be the dominant driver of gas turbulence from $z\sim1$ to $z\sim0$, for example, stellar feedback and/or gravitational instability. The gas velocity dispersion of MAGPI galaxies is also correlated with the non-rotational motion of the gas, illustrating that in addition to star-formation feedback, gas transportation and accretion may also contribute to the gas velocity dispersion for galaxies at $z\sim 0.3$. KROSS galaxies only have a moderate correlation between gas velocity dispersion and $\Sigma_{\rm SFR}$ and a higher scatter of gas velocity dispersion with respect to $\Sigma_{\rm SFR}$, in agreement with the suggestion that other mechanisms, such as gas transportation and accretion, are relatively more important at higher redshift galaxies., Comment: 15 pages, 10 figures, accepted for publication in MNRAS
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- 2024
19. LNQ 2023 challenge: Benchmark of weakly-supervised techniques for mediastinal lymph node quantification
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Dorent, Reuben, Khajavi, Roya, Idris, Tagwa, Ziegler, Erik, Somarouthu, Bhanusupriya, Jacene, Heather, LaCasce, Ann, Deissler, Jonathan, Ehrhardt, Jan, Engelson, Sofija, Fischer, Stefan M., Gu, Yun, Handels, Heinz, Kasai, Satoshi, Kondo, Satoshi, Maier-Hein, Klaus, Schnabel, Julia A., Wang, Guotai, Wang, Litingyu, Wald, Tassilo, Yang, Guang-Zhong, Zhang, Hanxiao, Zhang, Minghui, Pieper, Steve, Harris, Gordon, Kikinis, Ron, and Kapur, Tina
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
Accurate assessment of lymph node size in 3D CT scans is crucial for cancer staging, therapeutic management, and monitoring treatment response. Existing state-of-the-art segmentation frameworks in medical imaging often rely on fully annotated datasets. However, for lymph node segmentation, these datasets are typically small due to the extensive time and expertise required to annotate the numerous lymph nodes in 3D CT scans. Weakly-supervised learning, which leverages incomplete or noisy annotations, has recently gained interest in the medical imaging community as a potential solution. Despite the variety of weakly-supervised techniques proposed, most have been validated only on private datasets or small publicly available datasets. To address this limitation, the Mediastinal Lymph Node Quantification (LNQ) challenge was organized in conjunction with the 26th International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI 2023). This challenge aimed to advance weakly-supervised segmentation methods by providing a new, partially annotated dataset and a robust evaluation framework. A total of 16 teams from 5 countries submitted predictions to the validation leaderboard, and 6 teams from 3 countries participated in the evaluation phase. The results highlighted both the potential and the current limitations of weakly-supervised approaches. On one hand, weakly-supervised approaches obtained relatively good performance with a median Dice score of $61.0\%$. On the other hand, top-ranked teams, with a median Dice score exceeding $70\%$, boosted their performance by leveraging smaller but fully annotated datasets to combine weak supervision and full supervision. This highlights both the promise of weakly-supervised methods and the ongoing need for high-quality, fully annotated data to achieve higher segmentation performance., Comment: Submitted to MELBA
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- 2024
20. Automatic Mitigation of Dynamic Atmospheric Turbulence Using Optical Phase Conjugation for Coherent Free-Space Optical Communications
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Zhou, Huibin, Su, Xinzhou, Duan, Yuxiang, Zuo, Yue, Jiang, Zile, Ramakrishnan, Muralekrishnan, Tepper, Jan, Ziegler, Volker, Boyd, Robert W., Tur, Moshe, and Willner, Alan E.
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Physics - Optics ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Coherent detection can provide enhanced receiver sensitivity and spectral efficiency in free-space optical (FSO) communications. However, turbulence can cause modal power coupling effects on a Gaussian data beam and significantly degrade the mixing efficiency between the data beam and a Gaussian local oscillator (LO) in the coherent detector. Optical phase conjugation (OPC) in a photorefractive crystal can "automatically" mitigate turbulence by: (a) recording a back-propagated turbulence-distorted probe beam, and (b) creating a phase-conjugate beam that has the inverse phase distortion of the medium as the transmitted data beam. However, previously reported crystal-based OPC approaches for FSO links have demonstrated either: (i) a relatively fast response time of 35 ms but at a relatively low data rate (e.g., <1 Mbit/s), or (ii) a relatively high data rate of 2-Gbit/s but at a slow response time (e.g., >60 s). Here, we report an OPC approach for the automatic mitigation of dynamic turbulence that enables both a high data rate (8 Gbit/s) data beam and a rapid (<5 ms) response time. For a similar data rate, this represents a 10,000-fold faster response time than previous reports, thereby enabling mitigation for dynamic effects. In our approach, the transmitted pre-distorted phase-conjugate data beam is generated by four-wave mixing in a GaAs crystal of three input beams: a turbulence-distorted probe beam, a Gaussian reference beam regenerated from the probe beam, and a Gaussian data beam carrying a high-speed data channel. We experimentally demonstrate our approach in an 8-Gbit/s quadrature-phase-shift-keying coherent FSO link through emulated dynamic turbulence. Our results show ~10-dB improvement in the mixing efficiency of the LO with the data beam under dynamic turbulence with a bandwidth of up to ~260 Hz (Greenwood frequency).
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- 2024
21. Mass determination of two Jupiter-sized planets orbiting slightly evolved stars: TOI-2420 b and TOI-2485 b
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Carleo, Ilaria, Barrágan, Oscar, Persson, Carina M., Fridlund, Malcolm, Lam, Kristine W. F., Messina, Sergio, Gandolfi, Davide, Smith, Alexis M. S., Johnson, Marshall C., Cochran, William, Osborn, Hannah L. M., Brahm, Rafael, Ciardi, David R., Collins, Karen A., Everett, Mark E., Giacalone, Steven, Guenther, Eike W., Hatzes, Artie, Hellier, Coel, Kabáth, Jonathan Horner Petr, Korth, Judith, MacQueen, Phillip, Masseron, Thomas, Murgas, Felipe, Nowak, Grzegorz, Rodriguez, Joseph E., Watkins, Cristilyn N., Wittenmyer, Rob, Zhou, George, Ziegler, Carl, Bieryla, Allyson, Boyd, Patricia T., Clark, Catherine A., Dressing, Courtney D., Eastman, Jason D., Eberhardt, Jan, Endl, Michael, Espinoza, Nestor, Fausnaugh, Michael, Guerrero, Natalia M., Henning, Thomas, Hesse, Katharine, Hobson, Melissa J., Howell, Steve B., Jordán, Andrés, Latham, David W., Lund, Michael B., Mireles, Ismael, Narita, Norio, Pinto, Marcelo Tala, Pugh, Teznie, Quinn, Samuel N., Ricker, George, Rodriguez, David R., Rojas, Felipe I., Rose, Mark E., Rudat, Alexander, Sarkis, Paula, Savel, Arjun B., Schlecker, Martin, Schwarz, Richard P., Seager, Sara, Shporer, Avi, Smith, Jeffrey C., Stassun, Keivan G., Stockdale, Chris, Trifonov, Trifon, Vanderspek, Roland, Winn, Joshua N., and Wright, Duncan
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
Hot and warm Jupiters might have undergone the same formation and evolution path, but the two populations exhibit different distributions of orbital parameters, challenging our understanding on their actual origin. The present work, which is the results of our warm Jupiters survey carried out with the CHIRON spectrograph within the KESPRINT collaboration, aims to address this challenge by studying two planets that could help bridge the gap between the two populations. We report the confirmation and mass determination of a hot Jupiter (orbital period shorter than 10 days), TOI-2420\,b, and a warm Jupiter, TOI-2485\,b. We performed a joint analysis using a wide variety of spectral and photometric data in order to characterize these planetary systems. We found that TOI-2420\,b has an orbital period of P$_{\rm b}$=5.8 days, a mass of M$_{\rm b}$=0.9 M$_{\rm J}$ and a radius of R$_{\rm b}$=1.3 R$_{\rm J}$, with a planetary density of 0.477 \gc; while TOI-2485\,b has an orbital period of P$_{\rm b}$=11.2 days, a mass of M$_{\rm b}$=2.4 M$_{\rm J}$ and a radius of R$_{\rm b}$=1.1 R$_{\rm J}$ with density 2.36 \gc. With current parameters, the migration history for TOI-2420\,b and TOI-2485\,b is unclear: the high-eccentricity migration scenarios cannot be ruled out, and TOI-2485\,b's characteristics may rather support this scenario.
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- 2024
22. The MAGPI Survey: Evidence Against the Bulge-Halo Conspiracy
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Derkenne, C., McDermid, R. M., Santucci, G., Poci, A., Thater, S., Bellstedt, S., Mendel, J. T., Foster, C., Harborne, K. E., Lagos, C. D. P., Wisnioski, E., Croom, S., Remus, R-S., Valenzuela, L. M., van de Sande, J., Sweet, S. M., and Ziegler, B.
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
Studies of the internal mass structure of galaxies have observed a `conspiracy' between the dark matter and stellar components, with total (stars $+$ dark) density profiles showing remarkable regularity and low intrinsic scatter across various samples of galaxies at different redshifts. Such homogeneity suggests the dark and stellar components must somehow compensate for each other in order to produce such regular mass structures. We test the conspiracy using a sample of 22 galaxies from the `Middle Ages Galaxy Properties with Integral field spectroscopy' (MAGPI) Survey that targets massive galaxies at $ z \sim 0.3$. We use resolved, 2D stellar kinematics with the Schwarzschild orbit-based modelling technique to recover intrinsic mass structures, shapes, and dark matter fractions. This work is the first implementation of the Schwarzschild modelling method on a sample of galaxies at a cosmologically significant redshift. We find that the variability of structure for combined mass (baryonic and dark) density profiles is greater than that of the stellar components alone. Furthermore, we find no significant correlation between enclosed dark matter fractions at the half-light radius and the stellar mass density structure. Rather, the total density profile slope, $\gamma_{\mathrm{tot}}$, strongly correlates with the dark matter fraction within the half-light radius, as $\gamma_{\mathrm{tot}} = (1.3 \pm 0.2) f_{\mathrm{DM}} - (2.44 \pm 0.04)$. Our results refute the bulge-halo conspiracy and suggest that stochastic processes dominate in the assembly of structure for massive galaxies., Comment: 21 pages, 18 figures
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- 2024
23. TOI-2490b- The most eccentric brown dwarf transiting in the brown dwarf desert
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Henderson, Beth A., Casewell, Sarah L., Jordán, Andrés, Brahm, Rafael, Henning, Thomas, Gill, Samuel, Mayorga, L. C., Ziegler, Carl, Stassun, Keivan G., Goad, Michael R., Acton, Jack, Alves, Douglas R., Anderson, David R., Apergis, Ioannis, Armstrong, David J., Bayliss, Daniel, Burleigh, Matthew R., Dragomir, Diana, Gillen, Edward, Günther, Maximilian N., Hedges, Christina, Hesse, Katharine M., Hobson, Melissa J., Jenkins, James S., Jenkins, Jon M., Kendall, Alicia, Lendl, Monika, Lund, Michael B., McCormac, James, Moyano, Maximiliano, Osborn, Ares, Pinto, Marcelo Tala, Ramsay, Gavin, Rapetti, David, Saha, Suman, Seager, Sara, Trifonov, Trifon, Udry, Stéphane, Vines, Jose I., West, Richard G., Wheatley, Peter J., Winn, Joshua N., and Zivave, Tafadzwa
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
We report the discovery of the most eccentric transiting brown dwarf in the brown dwarf desert, TOI02490b. The brown dwarf desert is the lack of brown dwarfs around main sequence stars within $\sim3$~AU and is thought to be caused by differences in formation mechanisms between a star and planet. To date, only $\sim40$ transiting brown dwarfs have been confirmed. \systemt is a $73.6\pm2.4$ \mjupnospace, $1.00\pm0.02$ \rjup brown dwarf orbiting a $1.004_{-0.022}^{+0.031}$ \msunnospace, $1.105_{-0.012}^{+0.012}$ \rsun sun-like star on a 60.33~d orbit with an eccentricity of $0.77989\pm0.00049$. The discovery was detected within \tess sectors 5 (30 minute cadence) and 32 (2 minute and 20 second cadence). It was then confirmed with 31 radial velocity measurements with \feros by the WINE collaboration and photometric observations with the Next Generation Transit Survey. Stellar modelling of the host star estimates an age of $\sim8$~Gyr, which is supported by estimations from kinematics likely placing the object within the thin disc. However, this is not consistent with model brown dwarf isochrones for the system age suggesting an inflated radius. Only one other transiting brown dwarf with an eccentricity higher than 0.6 is currently known in the brown dwarf desert. Demographic studies of brown dwarfs have suggested such high eccentricity is indicative of stellar formation mechanisms., Comment: Accepted for publication in MNRAS, 18 pages, 14 figures
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- 2024
24. Unimprovable Students and Inequality in School Choice
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Ortega, Josue, Ziegler, Gabriel, and Arribillaga, R. Pablo
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Economics - Theoretical Economics - Abstract
The Efficiency-Adjusted Deferred Acceptance (EADA) mechanism corrects the Pareto-inefficiency of the celebrated Deferred Acceptance (DA) algorithm by assigning every student to a weakly more preferred school. However, it remains uncertain which and how many students do not see an improvement in their DA placement under EADA. We show that, despite its advantages, EADA does not benefit students assigned to their worst-ranked schools or those who remain unmatched under DA. Additionally, it limits the placement improvement of marginalized students, thereby maintaining school segregation. The placement of worst-off students under EADA can be exceptionally poor, even though significantly more egalitarian allocations are possible. Lastly, we provide a bound on the expected number of unimproved students using a random market approach valid for small markets. Our findings shed light on why EADA fails to mitigate the inequality produced by DA in empirical evaluations.
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- 2024
25. GJ 238 b: A 0.57 Earth Radius Planet Orbiting an M2.5 Dwarf Star at 15.2 pc
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Tey, Evan, Shporer, Avi, Lin, Zifan, Stassun, Keivan G., Lissauer, Jack J., Hellier, Coel, Collins, Karen A., Collins, Kevin I., Wingham, Geof, Relles, Howard M., Mallia, Franco, Isopi, Giovanni, Kielkopf, John F., Conti, Dennis M., Schwarz, Richard P., Zapparata, Aldo, Giacalone, Steven, Furlan, Elise, Hartman, Zachary D., Howell, Steve B., Scott, Nicholas J., Ziegler, Carl, Briceno, Cesar, Law, Nicholas, Mann, Andrew W., Charbonneau, David, Essack, Zahra, Striegel, Stephanie, Ricker, George R., Vanderspek, Roland, Seager, Sara, Winn, Joshua N., and Jenkins, Jon M.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
We report the discovery of the transiting planet GJ 238 b, with a radius of $0.566\pm0.014$ R$_{\oplus}$ ($1.064\pm0.026$ times the radius of Mars) and an orbital period of 1.74 day. The transit signal was detected by the TESS mission and designated TOI-486.01. The star's position close to the Southern ecliptic pole allows for almost continuous observations by TESS when it is observing the Southern sky. The host star is an M2.5 dwarf with $V=11.57\pm0.02$ mag, $K=7.030\pm0.023$ mag, a distance of $15.2156\pm0.0030$ pc, a mass of $0.4193_{-0.0098}^{+0.0095}$ M$_{\odot}$, a radius of $0.4314_{-0.0071}^{+0.0075}$ R$_{\odot}$, and an effective temperature of $3{,}485\pm140$ K. We validate the planet candidate by ruling out or rendering highly unlikely each of the false positive scenarios, based on archival data and ground-based follow-up observations. Validation was facilitated by the host star's small size and high proper motion, of $892.633\pm0.025$ mas yr$^{-1}$., Comment: Published in AJ
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- 2024
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26. Toward an efficient second-order method for computing the surface gravitational potential on spherical-polar meshes
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Gressel, Oliver and Ziegler, Udo
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Astrophysical accretion discs that carry a significant mass compared with their central object are subject to the effect of self-gravity. In the context of circumstellar discs, this can, for instance, cause fragmentation of the disc gas, and -- under suitable conditions -- lead to the direct formation of gas-giant planets. If one wants to study these phenomena, the disc's gravitational potential needs to be obtained by solving the Poisson equation. This requires to specify suitable boundary conditions. In the case of a spherical-polar computational mesh, a standard multipole expansion for obtaining boundary values is not practicable. We hence compare two alternative methods for overcoming this limitation. The first method is based on a known Green's function expansion (termed "CCGF") of the potential, while the second (termed "James' method") uses a surface screening mass approach with a suitable discrete Green's function. We demonstrate second-order convergence for both methods and test the weak scaling behaviour when using thousands of computational cores. Overall, James' method is found superior owing to its favourable algorithmic complexity of $\sim \mathcal{O}(n^3)$ compared with the $\sim\mathcal{O}(n^4)$ scaling of the CCGF method., Comment: 12 pages, 8 figures, submitted to AN
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- 2024
27. The de Rham cohomology of a Lie group modulo a dense subgroup
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Clark, Brant and Ziegler, Francois
- Subjects
Mathematics - Differential Geometry ,Mathematics - Algebraic Topology ,58A12, 57T15, 17B56, 58A40, 22E15 - Abstract
Let $H$ be a dense subgroup of a Lie group $G$ with Lie algebra $\mathfrak g$. We show that the (diffeological) de Rham cohomology of $G/H$ equals the Lie algebra cohomology of $\mathfrak g/\mathfrak h$, where $\mathfrak h$ is the ideal $\{Z\in\mathfrak g:\exp(tZ)\in H \text{ for all } t\in\mathbf R\}$., Comment: Comments welcome, especially on whether the Appendix is original. (We will probably submit the paper without it, for fear that it seem not new enough.)
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- 2024
28. Surviving in the Hot Neptune Desert: The Discovery of the Ultra-Hot Neptune TOI-3261b
- Author
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Nabbie, Emma, Huang, Chelsea X., Burt, Jennifer A., Armstrong, David J., Mamajek, Eric E., Adibekyan, Vardan, Sousa, Sérgio G., Lopez, Eric D., Thorngren, Daniel P., Fernández, Jorge, Li, Gongjie, Jenkins, James S., Vines, Jose I., da Silva, João Gomes, Wittenmyer, Robert A., Bayliss, Daniel, Briceño, César, Collins, Karen A., Dumusque, Xavier, Horne, Keith D., Keniger, Marcelo F., Law, Nicholas, Lillo-Box, Jorge, Liu, Shang-Fei, Mann, Andrew W., Nielsen, Louise Dyregaard, Osborn, Ares, Relles, Howard M., Rodrigues, José J., Bell, Juan, Srdoc, Gregor, Stockdale, Chris, Strøm, Paul A., Gardner-Watkins, Cristilyn N., Wheatley, Peter J., Wright, Duncan J., Zhou, George, Ziegler, Carl, Ricker, George R., Seager, Sara, Vanderspek, Roland, Winn, Joshua W., Jenkins, Jon M., Fausnaugh, Michael, Kunimoto, Michelle, Osborn, Hugh P., Quinn, Samuel N., and Wohler, Bill
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
The recent discoveries of Neptune-sized ultra-short period planets (USPs) challenge existing planet formation theories. It is unclear whether these residents of the Hot Neptune Desert have similar origins to smaller, rocky USPs, or if this discrete population is evidence of a different formation pathway altogether. We report the discovery of TOI-3261b, an ultra-hot Neptune with an orbital period $P$ = 0.88 days. The host star is a $V = 13.2$ magnitude, slightly super-solar metallicity ([Fe/H] $\simeq$ 0.15), inactive K1.5 main sequence star at $d = 300$ pc. Using data from the Transiting Exoplanet Survey Satellite and the Las Cumbres Observatory Global Telescope, we find that TOI-3261b has a radius of $3.82_{-0.35}^{+0.42}$ $R_{\oplus}$. Moreover, radial velocities from ESPRESSO and HARPS reveal a mass of $30.3_{-2.4}^{+2.2}$ $M_{\oplus}$, more than twice the median mass of Neptune-sized planets on longer orbits. We investigate multiple mechanisms of mass loss that can reproduce the current-day properties of TOI-3261b, simulating the evolution of the planet via tidal stripping and photoevaporation. Thermal evolution models suggest that TOI-3261b should retain an envelope potentially enriched with volatiles constituting $\sim$5% of its total mass. This is the second highest envelope mass fraction among ultra-hot Neptunes discovered to date, making TOI-3261b an ideal candidate for atmospheric follow-up observations., Comment: 20 pages, 11 figures, accepted to AJ
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- 2024
29. The MAGPI survey: The interdependence of the mass, star formation rate, and metallicity in galaxies at z~0.3
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Koller, M., Ziegler, B., Ciocan, B. I., Thater, S., Mendel, J. T., Wisnioski, E., Battisti, A. J., Harborne, K. E., Foster, C., Lagos, C., Croom, S. M., Grasha, K., Papaderos, P., Remus, R. S., Sharma, G., Sweet, S. M., Valenzuela, L. M., van de Ven, G., and Zafar, T.
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
Star formation rates (SFRs), gas-phase metallicities, and stellar masses are crucial for studying galaxy evolution. The different relations resulting from these properties give insights into the complex interplay of gas inside galaxies and their evolutionary trajectory and current characteristics. We aim to characterize these relations at $z\sim 0.3$, corresponding to a 3-4 Gyr lookback time. We utilized optical integral field spectroscopy of 65 emission-line galaxies from the MAGPI survey at a redshift of $0.28
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- 2024
- Full Text
- View/download PDF
30. TOI-2374 b and TOI-3071 b: two metal-rich sub-Saturns well within the Neptunian desert
- Author
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Hacker, Alejandro, Díaz, Rodrigo F., Armstrong, David J., Fernández, Jorge Fernández, Müller, Simon, Delgado-Mena, Elisa, Sousa, Sérgio G., Adibekyan, Vardan, Stassun, Keivan G., Collins, Karen A., Yee, Samuel W., Bayliss, Daniel, Bieryla, Allyson, Bouchy, François, Butler, R. Paul, Crane, Jeffrey D., Dumusque, Xavier, Hartman, Joel D., Helled, Ravit, Jenkins, Jon, Keniger, Marcelo Aron F., Lewis, Hannah, Lillo-Box, Jorge, Lund, Michael B., Nielsen, Louise D., Osborn, Ares, Osip, David, Paegert, Martin, Radford, Don J., Santos, Nuno C., Seager, Sara, Shectman, Stephen A., Srdoc, Gregor, Strøm, Paul A., Tan, Thiam-Guan, Teske, Johanna K., Vezie, Michael, Watanabe, David, Watkins, Cristilyn N., Wheatley, Peter J., Winn, Joshua N., Wohler, Bill, and Ziegler, Carl
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
We report the discovery of two transiting planets detected by the Transiting Exoplanet Survey Satellite (TESS), TOI-2374 b and TOI-3071 b, orbiting a K5V and an F8V star, respectively, with periods of 4.31 and 1.27 days, respectively. We confirm and characterize these two planets with a variety of ground-based and follow-up observations, including photometry, precise radial velocity monitoring and high-resolution imaging. The planetary and orbital parameters were derived from a joint analysis of the radial velocities and photometric data. We found that the two planets have masses of $(57 \pm 4)$ $M_\oplus$ or $(0.18 \pm 0.01)$ $M_J$, and $(68 \pm 4)$ $M_\oplus$ or $(0.21 \pm 0.01)$ $M_J$, respectively, and they have radii of $(6.8 \pm 0.3)$ $R_\oplus$ or $(0.61 \pm 0.03)$ $R_J$ and $(7.2 \pm 0.5)$ $R_\oplus$ or $(0.64 \pm 0.05)$ $R_J$, respectively. These parameters correspond to sub-Saturns within the Neptunian desert, both planets being hot and highly irradiated, with $T_{\rm eq} \approx 745$ $K$ and $T_{\rm eq} \approx 1812$ $K$, respectively, assuming a Bond albedo of 0.5. TOI-3071 b has the hottest equilibrium temperature of all known planets with masses between $10$ and $300$ $M_\oplus$ and radii less than $1.5$ $R_J$. By applying gas giant evolution models we found that both planets, especially TOI-3071 b, are very metal-rich. This challenges standard formation models which generally predict lower heavy-element masses for planets with similar characteristics. We studied the evolution of the planets' atmospheres under photoevaporation and concluded that both are stable against evaporation due to their large masses and likely high metallicities in their gaseous envelopes., Comment: 24 pages, 22 figures, 10 tables, accepted for publication in MNRAS
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- 2024
31. A Mixed Tree-Cotree Gauge for the Reduced Basis Approximation of Maxwell's Eigenvalue Problem
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Ziegler, Anna and Schöps, Sebastian
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Computer Science - Computational Engineering, Finance, and Science ,Mathematics - Numerical Analysis - Abstract
Model order reduction methods are a powerful tool to drastically reduce the computational effort of problems which need to be evaluated repeatedly, i.e., when computing the same system for various parameter values. When applying a reduced basis approximation algorithm to the Maxwell eigenvalue problem, we encounter spurious solutions in the reduced system which hence need to be removed during the basis construction. In this paper, we discuss two tree-cotree gauge-based methods for the removal of the spurious eigenmodes.
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- 2024
32. HD 21520 b: a warm sub-Neptune transiting a bright G dwarf
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Nies, Molly, Mireles, Ismael, Bouchy, François, Dragomir, Diana, Nicholson, Belinda A., Eisner, Nora L., Sousa, Sergio G., Collins, Karen A., Howell, Steve B., Ziegler, Carl, Hellier, Coel, Addison, Brett, Ballard, Sarah, Bowler, Brendan P., Briceño, César, Clark, Catherine A., Conti, Dennis M., Dumusque, Xavier, Edwards, Billy, Gnilka, Crystal L., Hobson, Melissa, Horner, Jonathan, Kane, Stephen R., Kielkopf, John, Lavie, Baptiste, Law, Nicholas, Lendl, Monika, Littlefield, Colin, Liu, Huigen, Mann, Andrew W., Mengel, Matthew W., Oddo, Dominic, Okumura, Jack, Palle, Enric, Plavchan, Peter, Psaridi, Angelica, Santos, Nuno C., Schwarz, Richard P., Shporer, Avi, Wittenmyer, Robert A., Wright, Duncan J., Zhang, Hui, Watanabe, David, Medina, Jennifer V., Villaseñor, Joel, Ting, Eric B., Christiansen, Jessie L., Winn, Joshua N., Stassun, Keivan G., Seager, S., Latham, David W., and Ricker, George R.
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
We report the discovery and validation of HD 21520 b, a transiting planet found with TESS and orbiting a bright G dwarf (V=9.2, $T_{eff} = 5871 \pm 62$ K, $R_{\star} = 1.04\pm 0.02\, R_{\odot}$). HD 21520 b was originally alerted as a system (TOI-4320) consisting of two planet candidates with periods of 703.6 and 46.4 days. However, our analysis supports instead a single-planet system with an orbital period of $25.1292\pm0.0001$ days and radius of $2.70 \pm 0.09\, R_{\oplus}$. Three full transits in sectors 4, 30 and 31 match this period and have transit depths and durations in agreement with each other, as does a partial transit in sector 3. We also observe transits using CHEOPS and LCOGT. SOAR and Gemini high-resolution imaging do not indicate the presence of any nearby companions, and MINERVA-Australis and CORALIE radial velocities rule out an on-target spectroscopic binary. Additionally, we use ESPRESSO radial velocities to obtain a tentative mass measurement of $7.9^{+3.2}_{-3.0}\, M_{\oplus}$, with a 3-$\sigma$ upper limit of 17.7 $M_{\oplus}$. Due to the bright nature of its host and likely significant gas envelope of the planet, HD 21520 b is a promising candidate for further mass measurements and for atmospheric characterization., Comment: Submitted to MNRAS
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- 2024
33. On the unique solvability of the simultaneous Pell equations $x^2-ay^2 = 1$ and $z^2-bx^2 = 1$
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Hilgart, Tobias and Ziegler, Volker
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Mathematics - Number Theory ,11D09, 11Y50 - Abstract
We consider the simultaneous Pell equations $$x^2 - ay^2 = 1, \qquad z^2 - bx^2 = 1,$$ where $a > b\geq 2$ are positive integers. We describe a procedure which, for any fixed $b$, either confirms that the simultaneous Pell equations have at most one solution in positive integers, or finds all exceptions for which we have proved that there are at most finitely many.
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- 2024
34. TESS Hunt for Young and Maturing Exoplanets (THYME) X: a two-planet system in the 210 Myr MELANGE-5 Association
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Thao, Pa Chia, Mann, Andrew W., Barber, Madyson G., Kraus, Adam L., Tofflemire, Benjamin M., Bush, Jonathan L., Wood, Mackenna L., Collins, Karen A., Vanderburg, Andrew, Quinn, Samuel N., Zhou, George, Newton, Elisabeth R., Ziegler, Carl, Law, Nicholas, Barkaoui, Khalid, Pozuelos, Francisco J., Timmermans, Mathilde, Gillon, Michaël, Jehin, Emmanuël, Schwarz, Richard P., Gan, Tianjun, Shporer, Avi, Horne, Keith, Sefako, Ramotholo, Suarez, Olga, Mekarnia, Djamel, Guillot, Tristan, Abe, Lyu, Triaud, Amaury H. M. J., Radford, Don J., Murillo, Ana Isabel Lopez, Ricker, George R., Winn, Joshua N., Jenkins, Jon M., Bouma, Luke G., Fausnaugh, Michael, Guerrero, Natalia M., and Kunimoto, Michelle
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
Young (<500 Myr) planets are critical to studying how planets form and evolve. Among these young planetary systems, multi-planet configurations are particularly useful as they provide a means to control for variables within a system. Here, we report the discovery and characterization of a young planetary system, TOI-1224. We show that the planet-host resides within a young population we denote as MELANGE-5 . By employing a range of age-dating methods -- isochrone fitting, lithium abundance analysis, gyrochronology, and Gaia excess variability -- we estimate the age of MELANGE-5 to be 210$\pm$27 Myr. MELANGE-5 is situated in close proximity to previously identified younger (80 -110 Myr) associations, Crius 221 and Theia 424/Volans-Carina, motivating further work to map out the group boundaries. In addition to a planet candidate detected by the TESS pipeline and alerted as a TESS Object of Interest, TOI-1224 b, we identify a second planet, TOI-1224 c, using custom search tools optimized for young stars (Notch and LOCoR). We find the planets are 2.10$\pm$0.09$R_\oplus$ and 2.88$\pm$0.10$R_\oplus$ and orbit their host star every 4.18 and 17.95 days, respectively. With their bright ($K$=9.1 mag), small ($R_{*}$=0.44R$_{\odot}$), and cool ($T_{eff}$ =3326K) host star, these planets represent excellent candidates for atmospheric characterization with JWST., Comment: Accepted for publication in The Astronomical Journal; 33 pages, 17 figures, 9 tables
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- 2024
35. The MAGPI Survey: Massive slow rotator population in place by $z \sim 0.3$
- Author
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Derkenne, Caro, McDermid, Richard M., D'Eugenio, Francesco, Foster, Caroline, Khalid, Aman, Harborne, Katherine E., van de Sande, Jesse, Croom, Scott M., Lagos, Claudia D. P., Bellstedt, Sabine, Mendel, J. Trevor, Mun, Marcie, Wisnioski, Emily, Bagge, Ryan S., Battisti, Andrew J., Bland-Hawthorn, Joss, Ferré-Mateu, Anna, Peng, Yingjie, Santucci, Giulia, Sweet, Sarah M., Thater, Sabine, Valenzuela, Lucas M., and Ziegler, Bodo
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Astrophysics - Astrophysics of Galaxies - Abstract
We use the `Middle Ages Galaxy Properties with Integral field spectroscopy' (MAGPI) survey to investigate whether galaxies have evolved in the distribution of their stellar angular momentum in the past 3-4 Gyr, as probed by the observational proxy for spin, $\lambda_{R}$. We use 2D stellar kinematics to measure $\lambda_{R}$ along with detailed photometric models to estimate galaxy ellipticity. The combination of these measurements quantifies the kinematic classes of `fast rotators' and the rarer `slow rotators', which show no regular rotation in their line-of-sight velocity fields. We compare 51 MAGPI galaxies with $\log_{10} (M_{\star}/\mathrm{M}_\odot) > 10$ to carefully drawn samples of MaNGA galaxies in the local Universe, selected to represent possible descendants of the MAGPI progenitors. The EAGLE simulations are used to identify possible evolutionary pathways between the two samples, explicitly accounting for progenitor bias in our results and the varied evolutionary pathways a galaxy might take between the two epochs. We find that the occurrence of slow rotating galaxies is unchanged between the MAGPI ($z \sim 0.3$) and MaNGA ($z \sim 0$) samples, suggesting the massive slow rotator population was already in place $\sim 4$ Gyr ago and has not accumulated since. There is a hint of the MAGPI sample having an excess of high $\lambda_{R}$ galaxies compared to the MaNGA sample, corresponding to more ordered rotation, but statistically the samples are not significantly different. The large-scale stellar kinematics, as quantified through the $\lambda_{R}$ parameter, of galaxies at $z \sim 0.3$ have already evolved into the diversity of structures seen today in the local Universe., Comment: 10 pages, 7 figures, accepted for publication in MNRAS
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- 2024
36. Remote-Controlled Activation of the Release through Drug-Loaded Magnetic Electrospun Fibers
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Ziegler, Richard, Ilyas, Shaista, Mathur, Sanjay, Goya, Gerardo F., and Fuentes-García, Jesús Antonio
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Condensed Matter - Materials Science - Abstract
The integration of magnetic nanoparticles within fibrillar structures represents an interesting avenue for the remotely controlled release of therapeutic agents. This work presents a novel drug release platform based on electrospun magnetic fibers (EMFs) combining drugs, magnetic nanoparticles (MNPs) and mesoporous silica nanoparticles (MSNs) for controlled drug delivery via alternating magnetic fields (AMF). The platform was demonstrated to be versatile and effective for hydrophilic ketorolac (KET) and hydrophobic curcumin (CUR) encapsulation and the major response observed for AMF-triggered release was reached using drug-loaded MSNs within the fibers, providing fine control over drug release patterns. The EMFs exhibited excellent inductive heating capabilities, showing a temperature increase up to 8 {\deg}C within a 5 min AMF pulse. The system is shown to be promising for applications like transdermal pain management, oncological drug delivery, tissue engineering, and wound healing, enabling precise control over drug release in both spatial and temporal dimensions. The findings of this study offer valuable insights into the development of the next generation of smart drug delivery systems, based in multifunctional materials that can be remotely regulated and potentially revolutionize the field of nanomedicine.
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- 2024
37. Metabolic activation of WHO-congeners PCB28, 52, and 101 by human CYP2A6: evidence from in vitro and in vivo experiments
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Randerath, Isabella, Schettgen, Thomas, Müller, Julian Peter, Rengelshausen, Jens, Ziegler, Susanne, Quinete, Nathalia, Bertram, Jens, Laieb, Salah, Schaeffeler, Elke, Kaifie, Andrea, Just, Katja S., Voigt, Aaron, Tremmel, Roman, Schwab, Matthias, Stingl, Julia C., Kraus, Thomas, and Ziegler, Patrick
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- 2024
- Full Text
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38. The Role of Micro-Credentials in Strengthening STEM Teaching and Learning: An Evaluation of the Louisiana STEM Micro-Credentials Project. Research Report. RRA2486-2
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RAND Education and Labor, Christopher Joseph Doss, Rebecca L. Wolfe, Miray Tekkumru-Kisa, Karen Christianson, Michelle D. Ziegler, and Julia H. Kaufman
- Abstract
Micro-credentials are increasingly being adopted across a variety of industries and countries, including the kindergarten through grade 12 education system in the United States, as a way to identify workers with specific skills, knowledge, and competencies. This report presents the results of a study conducted by RAND researchers who investigated the implementation and impact of teacher micro-credentials intended to improve high school science, technology, engineering, and math teaching and learning in Louisiana. The creation, design, and implementation of micro-credentials was undertaken through a collaboration between the Louisiana Department of Education, Louisiana State University, and BloomBoard. RAND researchers designed and executed a randomized controlled trial of the effectiveness of micro-credentials and an implementation study. The study indicated that teachers' engagement with micro-credentials was relatively low and that micro-credentials did not lead to an increase in student achievement. That said, participating teachers reported that the micro-credentials were well aligned with their courses and supported their teaching practice. Study implications include that micro-credential providers and stakeholders should clearly communicate the value proposition and time requirements of micro-credentials to teachers, as well as provide ample peer and asynchronous supports to teachers for undertaking them.
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- 2024
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39. Maternal Education Prospectively Predicts Child Neurocognitive Function: An Environmental Influences on Child Health Outcomes Study
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Santiago Morales, Maureen E. Bowers, Lauren Shuffrey, Katherine Ziegler, Sonya Troller-Renfree, Alexis Hernandez, Stephanie C. Leach, Monica McGrath, Cindy Ola, Leslie D. Leve, Sara S. Nozadi, Margaret M. Swingler, Jin-Shei Lai, Julie B. Schweitzer, William Fifer, Carlos A. Camargo, Gurjit K. Khurana Hershey, Allison L. B. Shapiro, Daniel P. Keating, Tina V. Hartert, Sean Deoni, Assiamira Ferrara, and Amy J. Elliott
- Abstract
A large body of research has established a relation between maternal education and children's neurocognitive functions, such as executive function and language. However, most studies have focused on early childhood and relatively few studies have examined associations with changes in maternal education over time. Consequently, it remains unclear if early maternal education is longitudinally related to neurocognitive functions in children, adolescents, and young adults. In addition, the associations between changes in maternal education across development and more broadly defined neurocognitive outcomes remain relatively untested. The current study leveraged a large multicohort sample to examine the longitudinal relations between perinatal maternal education and changes in maternal education during development with children's, adolescents', and young adults' neurocognitive functions (N = 2,688; M[subscript age] = 10.32 years; SD[subscript age] = 4.26; range = 3-20 years). Moreover, we examined the differential effects of perinatal maternal education and changes in maternal education across development on executive function and language performance. Perinatal maternal education was positively associated with children's later overall neurocognitive function. This longitudinal relation was stronger for language than executive function. In addition, increases in maternal education were related to improved language performance but were not associated with executive functioning performance. Our findings support perinatal maternal education as an important predictor of neurocognitive outcomes later in development. Moreover, our results suggest that examining how maternal education changes across development can provide important insights that can help inform policies and interventions designed to foster neurocognitive development. [This paper was written on behalf of program collaborators for Environmental Influences on Child Health Outcomes.]
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- 2024
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40. A Prospective, Open-label Study of [68Ga]Ga-DOTA-TATE in Patients With Neuroendocrine Neoplasms (NENs) and Healthy Volunteers in Japan
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Eckert & Ziegler Radiopharma GmbH
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- 2024
41. Study of 177Lu-PSMA-617 In Metastatic Castrate-Resistant Prostate Cancer in Japan
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Eckert & Ziegler Radiopharma GmbH
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- 2024
42. Genome‐wide association study of delay discounting in Heterogeneous Stock rats
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Lara, Montana Kay, Chitre, Apurva S, Chen, Denghui, Johnson, Benjamin B, Nguyen, Khai‐Minh, Cohen, Katarina A, Muckadam, Sakina A, Lin, Bonnie, Ziegler, Shae, Beeson, Angela, Sanches, Thiago M, Woods, Leah C Solberg, Polesskaya, Oksana, Palmer, Abraham A, and Mitchell, Suzanne H
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Pharmacology and Pharmaceutical Sciences ,Biological Sciences ,Biomedical and Clinical Sciences ,Genetics ,Brain Disorders ,Behavioral and Social Science ,Human Genome ,Basic Behavioral and Social Science ,Drug Abuse (NIDA only) ,Substance Misuse ,2.1 Biological and endogenous factors ,Animals ,Delay Discounting ,Rats ,Male ,Female ,Genome-Wide Association Study ,Reward ,Quantitative Trait Loci ,adjusting amount ,delay discounting ,GWAS ,Heterogeneous Stock rats ,Medical and Health Sciences ,Psychology and Cognitive Sciences ,Neurology & Neurosurgery ,Neurosciences - Abstract
Delay discounting refers to the behavioral tendency to devalue rewards as a function of their delay in receipt. Heightened delay discounting has been associated with substance use disorders and multiple co-occurring psychopathologies. Human and animal genetic studies have established that delay discounting is heritable, but only a few associated genes have been identified. We aimed to identify novel genetic loci associated with delay discounting through a genome-wide association study (GWAS) using Heterogeneous Stock (HS) rats, a genetically diverse outbred population derived from eight inbred founder strains. We assessed delay discounting in 650 male and female HS rats using an adjusting amount procedure in which rats chose between smaller immediate sucrose rewards or a larger reward at various delays. Preference switch points were calculated and both exponential and hyperbolic functions were fitted to these indifference points. Area under the curve (AUC) and the discounting parameter k of both functions were used as delay discounting measures. GWAS for AUC, exponential k, and one indifference point identified significant loci on chromosomes 20 and 14. The gene Slc35f1, which encodes a member of the solute carrier family, was the sole gene within the chromosome 20 locus. That locus also contained an eQTL for Slc35f1, suggesting that heritable differences in the expression might be responsible for the association with behavior. Adgrl3, which encodes a latrophilin subfamily G-protein coupled receptor, was the sole gene within the chromosome 14 locus. These findings implicate novel genes in delay discounting and highlight the need for further exploration.
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- 2024
43. Liver disease and transplantation in telomere biology disorders: An international multicenter cohort.
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Wang, YunZu, Kaj-Carbaidwala, Batul, Lane, Adam, Agarwal, Suneet, Beier, Fabian, Bertuch, Alison, Borovsky, Kristin, Brennan, Steven, Calado, Rodrigo, Catto, Luiz, Dufour, Carlo, Ebens, Christen, Fioredda, Francesca, Giri, Neelam, Gloude, Nicholas, Goldman, Frederick, Hertel, Paula, Himes, Ryan, Keel, Sioban, Koura, Divya, Kratz, Christian, Kulkarni, Sakil, Liou, Iris, Nakano, Taizo, Nastasio, Silvia, Niewisch, Marena, Penrice, Daniel, Sasa, Ghadir, Savage, Sharon, Simonetto, Douglas, Ziegler, David, Miethke, Alexander, and Myers, Kasiani
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Humans ,Liver Transplantation ,Female ,Male ,Retrospective Studies ,Adult ,Middle Aged ,Telomere ,Adolescent ,Liver Diseases ,Young Adult ,Child ,Treatment Outcome ,Child ,Preschool - Abstract
BACKGROUND: Patients with telomere biology disorders (TBD) develop hepatic disease, including hepatitis, cirrhosis, and hepatopulmonary syndrome. No specific treatment exists for TBD-related liver disease, and the role of liver transplantation (LT) remains controversial. Our study objectives were to describe the clinical characteristics, management, and outcomes in patients with TBD-related liver disease, and their LT outcomes. METHODS: Data from 83 patients with TBD-associated liver disease were obtained from 17 participating centers in the Clinical Care Consortium of Telomere-Associated Ailments and by self-report for our retrospective, multicenter, international cohort study. RESULTS: Group A (Advanced) included 40 patients with advanced liver disease. Of these, 20 underwent LT (Group AT). Group M (Mild) included 43 patients not warranting LT evaluation, none of whom were felt to be medically unfit for liver transplantation. Supplemental oxygen requirement, pulmonary arteriovenous malformation, hepatopulmonary syndrome, and higher bilirubin and international normalized ratio values were associated with Group A. Other demographics, clinical manifestations, and laboratory findings were similar between groups. Six group A patients were declined for LT; 3 died on the waitlist. Median follow-up post-LT was 2.9 years (range 0.6-13.2 y). One-year survival post-LT was 73%. Median survival post-LT has not been reached. Group AT patients had improved survival by age compared to all nontransplant patients (log-rank test p = 0.02). Of 14 patients with pretransplant hypoxemia, 8 (57%) had improved oxygenation after transplant. CONCLUSIONS: LT recipients with TBD do not exhibit excessive posttransplant mortality, and LT improved respiratory status in 57%. A TBD diagnosis should not exclude LT consideration.
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- 2024
44. Repeated measurements and random scattering in quantum walks
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Ziegler, Klaus
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Quantum Physics - Abstract
We study the effect of random scattering in quantum walks on a finite graph and compare it with the effect of repeated measurements. To this end, a constructive approach is employed by introducing a localized and a delocalized basis for the underlying Hilbert space. This enables us to design Hamiltonians whose eigenvectors are either localized or delocalized. By presenting some specific examples we demonstrate that the localization of eigenvectors restricts the transition probabilities on the graph and leads to dark states in the monitored evolution. We conclude that repeated measurements as well as random scattering provide efficient tools for controlling quantum walks., Comment: 12 pages
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- 2024
- Full Text
- View/download PDF
45. The GAPS programme at TNG. LVII. TOI-5076b: A warm sub-Neptune planet orbiting a thin-to-thick-disk transition star in a wide binary system
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Montalto, M., Greco, N., Biazzo, K., Desidera, S., Andreuzzi, G., Bieryla, A., Bignamini, A., Bonomo, A. S., Briceño, C., Cabona, L., Cosentino, R., Damasso, M., Fiorenzano, A., Fong, W., Goeke, B., Hesse, K. M., Kostov, V. B., Lanza, A. F., Latham, D. W., Law, N., Mancini, L., Maggio, A., Molinaro, M., Mann, A. W., Mantovan, G., Naponiello, L., Nardiello, D., Nascimbeni, V., Pagano, I., Pedani, M., Safonov, B. S., Scandariato, G., Seager, S., Singh, V., Sozzetti, A., Strakhov, I. A., Winn, J. N., Ziegler, C., and Zingales, T.
- Subjects
Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Aims. We report the confirmation of a new transiting exoplanet orbiting the star TOI-5076. Methods. We present our vetting procedure and follow-up observations which led to the confirmation of the exoplanet TOI-5076b. In particular, we employed high-precision {\it TESS} photometry, high-angular-resolution imaging from several telescopes, and high-precision radial velocities from HARPS-N. Results. From the HARPS-N spectroscopy, we determined the spectroscopic parameters of the host star: T$\rm_{eff}$=(5070$\pm$143) K, log~g=(4.6$\pm$0.3), [Fe/H]=(+0.20$\pm$0.08), and [$\alpha$/Fe]=0.05$\pm$0.06. The transiting planet is a warm sub-Neptune with a mass m$\rm_p=$(16$\pm$2) M$\rm_{\oplus}$, a radius r$\rm_p=$(3.2$\pm$0.1)~R$\rm_{\oplus}$ yielding a density $\rho_p$=(2.8$\pm$0.5) g cm$^{-3}$. It revolves around its star approximately every 23.445 days. Conclusions. The host star is a metal-rich, K2V dwarf, located at about 82 pc from the Sun with a radius of R$_{\star}$=(0.78$\pm$0.01) R$_{\odot}$ and a mass of M$_{\star}$=(0.80$\pm$0.07) M$_{\odot}$. It forms a common proper motion pair with an M-dwarf companion star located at a projected separation of 2178 au. The chemical analysis of the host-star and the Galactic-space velocities indicate that TOI-5076 belongs to the old population of thin-to-thick-disk transition stars. The density of TOI-5076b suggests the presence of a large fraction by volume of volatiles overlying a massive core. We found that a circular orbit solution is marginally favored with respect to an eccentric orbit solution for TOI-5076b., Comment: Accepted by Astronomy & Astrophysics: 15 pages, 19 figures, 4 tables
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- 2024
46. The Discovery and Follow-up of Four Transiting Short-period Sub-Neptunes Orbiting M dwarfs
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Hori, Y., Fukui, A., Hirano, T., Narita, N., de Leon, J. P., Ishikawa, H. T., Hartman, J. D., Morello, G., García, N. Abreu, Hernández, L. Álvarez, Béjar, V. J. S., Calatayud-Borras, Y., Carleo, I., Enoc, G., Esparza-Borges, E., Fukuda, I., Galán, D., Geraldía-González, S., Hayashi, Y., Ikoma, M., Ikuta, K., Isogai, K., Kagetani, T., Kawai, Y., Kawauchi, K., Kimura, T., Kodama, T., Korth, J., Kusakabe, N., Laza-Ramos, A., Livingston, J. H., Luque, R., Miyakawa, K., Mori, M., Torres, S. Muñoz, Murgas, F., Orell-Miquel, J., Palle, E., Parviainen, H., Peláez-Torres, A., Puig-Subirá, M., Sánchez-Benavente, M., Sosa-Guillén, P., Stangret, M., Terada, Y., Watanabe, N., Bakos, G. Á., Barkaoui, K., Beichman, C., Benkhaldoun, Z., Boyle, A. W., Ciardi, D. R., Clark, C. A., Collins, K. A., Collins, K. I., Conti, D. M., Crossfield, I. J. M., Everett, M. E., Furlan, E., Ghachoui, M., Gillon, M., Gonzales, E. J., Higuera, J., Horne, K., Howell, S. B., Jehin, E., Lester, K. V., Lund, M. B., Matson, R., Matthews, E. C., Pozuelos, F. J., Safonov, B. S., Schlieder, J. E., Schwarz, R. P., Sefako, R., Srdoc, G., Strakhov, I. A., Waalkes, W. C., Ziegler, C., Charbonneau, D., Essack, Z., Timmermans, M., Guerrero, N. M., Harakawa, H., Hedges, C., Ishizuka, M., Jenkins, J. M., Konishi, M., Kotani, T., Kudo, T., Kurokawa, T., Kuzuhara, M., Nishikawa, J., Omiya, M., Ricker, G. R., Seager, S., Serizawa, T., Striegel, S., Tamura, M., Ueda, A., Vanderspek, R., Vievard, S., and Winn, J. N.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
Sub-Neptunes with $2-3R_\oplus$ are intermediate in size between rocky planets and Neptune-sized planets. The orbital properties and bulk compositions of transiting sub-Neptunes provide clues to the formation and evolution of close-in small planets. In this paper, we present the discovery and follow-up of four sub-Neptunes orbiting M dwarfs (TOI-782, TOI-1448, TOI-2120, and TOI-2406), three of which were newly validated by ground-based follow-up observations and statistical analyses. TOI-782 b, TOI-1448 b, TOI-2120 b, and TOI-2406 b have radii of $R_\mathrm{p} = 2.740^{+0.082}_{-0.079}\,R_\oplus$, $2.769^{+0.073}_{-0.068}\,R_\oplus$, $2.120\pm0.067\,R_\oplus$, and $2.830^{+0.068}_{-0.066}\,R_\oplus$ and orbital periods of $P = 8.02$, $8.11$, $5.80$, and $3.08$\,days, respectively. Doppler monitoring with Subaru/InfraRed Doppler instrument led to 2$\sigma$ upper limits on the masses of $<19.1\ M_\oplus$, $<19.5\ M_\oplus$, $<6.8\ M_\oplus$, and $<15.6\ M_\oplus$ for TOI-782 b, TOI-1448 b, TOI-2120 b, and TOI-2406 b, respectively. The mass-radius relationship of these four sub-Neptunes testifies to the existence of volatile material in their interiors. These four sub-Neptunes, which are located above the so-called ``radius valley'', are likely to retain a significant atmosphere and/or an icy mantle on the core, such as a water world. We find that at least three of the four sub-Neptunes (TOI-782 b, TOI-2120 b, and TOI-2406 b) orbiting M dwarfs older than 1 Gyr, are likely to have eccentricities of $e \sim 0.2-0.3$. The fact that tidal circularization of their orbits is not achieved over 1 Gyr suggests inefficient tidal dissipation in their interiors., Comment: Accepted for publication in AJ, 32 pages, 17 figures, 6 tables
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- 2024
47. WST -- Widefield Spectroscopic Telescope: Motivation, science drivers and top-level requirements for a new dedicated facility
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Bacon, Roland, Maineiri, Vincenzo, Randich, Sofia, Cimatti, Andrea, Kneib, Jean-Paul, Brinchmann, Jarle, Ellis, Richard, Tolstoi, Eline, Smiljanic, Rodolfo, Hill, Vanessa, Anderson, Richard, Saez, Paula Sanchez, Opitom, Cyrielle, Bryson, Ian, Dierickx, Philippe, Garilli, Bianca, Gonzalez, Oscar, de Jong, Roelof, Lee, David, Mieske, Steffen, Otarola, Angel, Schipani, Pietro, Travouillon, Tony, Vernet, Joel, Bryant, Julia, Casali, Marc, Colless, Matthew, Couch, Warrick, Driver, Simon, Fontana, Adriano, Lehnert, Matthew, Magrini, Laura, Montet, Ben, Pasquini, Luca, Roth, Martin, Sanchez-Janssen, Ruben, Steinmetz, Matthias, Tresse, Laurence, Yeche, Christophe, and Ziegler, Bodo
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
In this paper, we describe the wide-field spectroscopic survey telescope (WST) project. WST is a 12-metre wide-field spectroscopic survey telescope with simultaneous operation of a large field-of-view (3 sq. degree), high-multiplex (20,000) multi-object spectrograph (MOS), with both a low and high-resolution modes, and a giant 3x3 arcmin2 integral field spectrograph (IFS). In scientific capability, these specifications place WST far ahead of existing and planned facilities. In only 5 years of operation, the MOS would target 250 million galaxies and 25 million stars at low spectral resolution, plus 2 million stars at high resolution. Without need for pre-imaged targets, the IFS would deliver 4 billion spectra offering many serendipitous discoveries. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work in synergy with future ground and space-based facilities. We show how it can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; the origin of stars and planets; and time domain and multi-messenger astrophysics. WST's uniquely rich dataset may yield unforeseen discoveries in many of these areas. The telescope and instruments are designed as an integrated system and will mostly use existing technology, with the aim to minimise the carbon footprint and environmental impact. We will propose WST as the next European Southern Observatory (ESO) project after completion of the 39-metre ELT., Comment: 15 pages, 15 figures
- Published
- 2024
48. Optical characterization of size- and substrate-dependent performance of ultraviolet hybrid plasmonic nanowire lasers
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Vitale, Francesco, Church, Stephen A., Repp, Daniel, Sunil, Karthika S., Ziegler, Mario, Diegel, Marco, Dellith, Andrea, Do, Thi-Hien, Lin, Sheng-Di, Huang, Jer-Shing, Pertsch, Thomas, Parkinson, Patrick, and Ronning, Carsten
- Subjects
Physics - Optics - Abstract
Nanowire-based plasmonic lasers are now established as nano-sources of coherent radiation, appearing as suitable candidates for integration into next-generation nanophotonic circuitry. However, compared to their photonic counterparts, their relatively high losses and large lasing thresholds still pose a burdening constraint on their scalability. In this study, the lasing characteristics of ZnO nanowires on Ag and Al substrates, operating as optically-pumped short-wavelength plasmonic nanolasers, are systematically investigated in combination with the size-dependent performance of the hybrid cavity. A hybrid nanomanipulation-assisted single nanowire optical characterization combined with high-throughput PL spectroscopy enables the correlation of the lasing characteristics to the metal substrate and the nanowire diameter. The results evidence that the coupling between excitons and surface plasmons is closely tied to the relationship between substrate dispersive behavior and nanowire diameter. Such coupling dictates the degree to which the lasing character, be it more plasmonic- or photonic-like, can define the stimulated emission features and, as a result, the device performance., Comment: 21 pages, 12 figures, journal paper draft
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- 2024
49. Distributed Representations Enable Robust Multi-Timescale Symbolic Computation in Neuromorphic Hardware
- Author
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Cotteret, Madison, Greatorex, Hugh, Renner, Alpha, Chen, Junren, Neftci, Emre, Wu, Huaqiang, Indiveri, Giacomo, Ziegler, Martin, and Chicca, Elisabetta
- Subjects
Computer Science - Neural and Evolutionary Computing ,Computer Science - Artificial Intelligence - Abstract
Programming recurrent spiking neural networks (RSNNs) to robustly perform multi-timescale computation remains a difficult challenge. To address this, we describe a single-shot weight learning scheme to embed robust multi-timescale dynamics into attractor-based RSNNs, by exploiting the properties of high-dimensional distributed representations. We embed finite state machines into the RSNN dynamics by superimposing a symmetric autoassociative weight matrix and asymmetric transition terms, which are each formed by the vector binding of an input and heteroassociative outer-products between states. Our approach is validated through simulations with highly non-ideal weights; an experimental closed-loop memristive hardware setup; and on Loihi 2, where it scales seamlessly to large state machines. This work introduces a scalable approach to embed robust symbolic computation through recurrent dynamics into neuromorphic hardware, without requiring parameter fine-tuning or significant platform-specific optimisation. Moreover, it demonstrates that distributed symbolic representations serve as a highly capable representation-invariant language for cognitive algorithms in neuromorphic hardware., Comment: 15 pages, 6 figures. Supplementary material: 7 pages, 6 figures
- Published
- 2024
50. Flavor Phenomenology of Light Dark Vectors
- Author
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Eguren, Jordi Folch, Klingel, Sophie, Stamou, Emmanuel, Tabet, Mustafa, and Ziegler, Robert
- Subjects
High Energy Physics - Phenomenology - Abstract
Light dark matter with flavor-violating couplings to fermions may be copiously produced in the laboratory as missing energy from decays of SM particles. Here we study the effective Lagrangian of a light dark vector with generic dipole or vector couplings. We calculate the resulting two-body decay rates of mesons, baryons and leptons as a function of the dark vector mass and show that existing experimental limits probe UV scales as large as $10^{12} \,\mathrm{GeV}$. We also derive the general RGEs in order to constrain the flavor-universal UV scenario, where all flavor violation arises radiatively proportional to the CKM matrix., Comment: 40 pages, 11 figures, 6 tables
- Published
- 2024
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