132,510 results on '"Saul, A"'
Search Results
2. A Tool for Clarifying Expectations in Undergraduate Research Experiences
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Karen Leung, Laurence Clement, James Lewis, and Naledi Saul
- Abstract
Articulating clear and achievable expectations is fundamental to both education and organizational management. In this article, we provide a simple intervention for clarifying expectations--and establishing that these expectations have been understood--which proved beneficial both to community college interns and to their internship mentors in biotech-related undergraduate research experiences. Internship mentors were asked to utilize a simple Expectation Clarity Tool to outline the expectations, success metrics, baseline assessments, and training strategy and support that would be foundational to their intern's project. These included expectations around conceptual, technical, performance, and professional skills and behaviors. Concurrently, but independently, community college interns were asked to complete the same type of exercise as a way of identifying gaps in their knowledge and understanding of their mentor's expectations and their internship project. The mentor's completed Expectation Clarity Tool was then shared with their intern. As a result of completing this relatively simple intervention, the majority of mentors reported that it increased their confidence as a mentor, taught them a new mentoring skill, changed how they will mentor trainees moving forward, and positively impacted their relationship with their trainee. On the intern side, the majority of interns reported that engaging in this intervention, both as an independent exercise and in obtaining their mentor's completed Expectation Clarity Tool, increased their confidence as an intern and positively impacted the success of their internship.
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- 2024
3. $\infty$-Video: A Training-Free Approach to Long Video Understanding via Continuous-Time Memory Consolidation
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Santos, Saul, Farinhas, António, McNamee, Daniel C., and Martins, André F. T.
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
Current video-language models struggle with long-video understanding due to limited context lengths and reliance on sparse frame subsampling, often leading to information loss. This paper introduces $\infty$-Video, which can process arbitrarily long videos through a continuous-time long-term memory (LTM) consolidation mechanism. Our framework augments video Q-formers by allowing them to process unbounded video contexts efficiently and without requiring additional training. Through continuous attention, our approach dynamically allocates higher granularity to the most relevant video segments, forming "sticky" memories that evolve over time. Experiments with Video-LLaMA and VideoChat2 demonstrate improved performance in video question-answering tasks, showcasing the potential of continuous-time LTM mechanisms to enable scalable and training-free comprehension of long videos., Comment: 17 pages, 7 figures
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- 2025
4. Static Segmentation by Tracking: A Frustratingly Label-Efficient Approach to Fine-Grained Segmentation
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Feng, Zhenyang, Wang, Zihe, Bueno, Saul Ibaven, Frelek, Tomasz, Ramesh, Advikaa, Bai, Jingyan, Wang, Lemeng, Huang, Zanming, Gu, Jianyang, Yoo, Jinsu, Pan, Tai-Yu, Chowdhury, Arpita, Ramirez, Michelle, Campolongo, Elizabeth G., Thompson, Matthew J., Lawrence, Christopher G., Record, Sydne, Rosser, Neil, Karpatne, Anuj, Rubenstein, Daniel, Lapp, Hilmar, Stewart, Charles V., Berger-Wolf, Tanya, Su, Yu, and Chao, Wei-Lun
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Artificial Intelligence - Abstract
We study image segmentation in the biological domain, particularly trait and part segmentation from specimen images (e.g., butterfly wing stripes or beetle body parts). This is a crucial, fine-grained task that aids in understanding the biology of organisms. The conventional approach involves hand-labeling masks, often for hundreds of images per species, and training a segmentation model to generalize these labels to other images, which can be exceedingly laborious. We present a label-efficient method named Static Segmentation by Tracking (SST). SST is built upon the insight: while specimens of the same species have inherent variations, the traits and parts we aim to segment show up consistently. This motivates us to concatenate specimen images into a ``pseudo-video'' and reframe trait and part segmentation as a tracking problem. Concretely, SST generates masks for unlabeled images by propagating annotated or predicted masks from the ``pseudo-preceding'' images. Powered by Segment Anything Model 2 (SAM~2) initially developed for video segmentation, we show that SST can achieve high-quality trait and part segmentation with merely one labeled image per species -- a breakthrough for analyzing specimen images. We further develop a cycle-consistent loss to fine-tune the model, again using one labeled image. Additionally, we highlight the broader potential of SST, including one-shot instance segmentation on images taken in the wild and trait-based image retrieval.
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- 2025
5. The tardigrade as an emerging model organism for systems neuroscience
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Lyons, Ana M. and Kato, Saul
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Quantitative Biology - Neurons and Cognition - Abstract
We present the case for developing the tardigrade (Hypsibius exemplaris) into a model organism for systems neuroscience. These microscopic, transparent animals (~300-500 microns) are among the smallest known to possess both limbs (eight) and eyes (two), with a nervous system of only a few hundred neurons organized into a multi-lobed brain, ventral nerve cord, and a series of ganglia along the body. Despite their neuroanatomical simplicity, tardigrades exhibit complex behaviors, including multi-limbed walking gaits, individual limb grasping, phototaxis, and transitions between active and dormant states. These behaviors position tardigrades as a uniquely powerful system for addressing certain fundamental questions in systems neuroscience, such as: How do nervous systems coordinate multi-limbed behaviors? How are top-down and bottom-up motor control systems integrated? How is stereovision-guided navigation implemented? What mechanisms underlie neural resilience and recovery during environmental stress? We review current knowledge of tardigrade neuroanatomy, behavior, and genomics, and we identify opportunities and challenges for leveraging their unique biology. We propose developing essential neuroscientific tools for tardigrades, including genetic engineering and live neuroimaging, alongside behavioral assays linking neural activity to outputs. Leveraging their evolutionary ties to Caenorhabditis elegans and Drosophila melanogaster, we can adapt existing toolkits to accelerate tardigrade research - providing a bridge between simpler invertebrate systems and more complex neural architectures., Comment: 39 pages
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- 2025
6. A Disintegrating Rocky Planet with Prominent Comet-like Tails Around a Bright Star
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Hon, Marc, Rappaport, Saul, Shporer, Avi, Vanderburg, Andrew, Collins, Karen A., Watkins, Cristilyn N., Schwarz, Richard P., Barkaoui, Khalid, Yee, Samuel W., Winn, Joshua N., Polanski, Alex S., Gilbert, Emily A., Ciardi, David R., Audenaert, Jeroen, Fong, William, Haviland, Jack, Hesse, Katharine, Muthukrishna, Daniel, Petitpas, Glen, Schmelzer, Ellie Hadjiyska, Narita, Norio, Fukui, Akihiko, Seager, Sara, and Ricker, George R.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
We report the discovery of BD+05$\,$4868$\,$Ab, a transiting exoplanet orbiting a bright ($V=10.16$) K-dwarf (TIC 466376085) with a period of 1.27 days. Observations from NASA's Transiting Exoplanet Survey Satellite (TESS) reveal variable transit depths and asymmetric transit profiles that are characteristic of comet-like tails formed by dusty effluents emanating from a disintegrating planet. Unique to BD+05$\,$4868$\,$Ab is the presence of prominent dust tails in both the trailing and leading directions that contribute to the extinction of starlight from the host star. By fitting the observed transit profile and analytically modeling the drift of dust grains within both dust tails, we infer large grain sizes ($\sim1-10\,\mu$m) and a mass loss rate of $10\,M_{\rm \oplus}\,$Gyr$^{-1}$, suggestive of a lunar-mass object with a disintegration timescale of only several Myr. The host star is probably older than the Sun and is accompanied by an M-dwarf companion at a projected physical separation of 130 AU. The brightness of the host star, combined with the planet's relatively deep transits ($0.8-2.0\%$), presents BD+05$\,$4868$\,$Ab as a prime target for compositional studies of rocky exoplanets and investigations into the nature of catastrophically evaporating planets., Comment: 24 pages, 17 figures. Submitted to AAS Journals
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- 2025
7. A categorical approach to additive combinatorics
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Blanco, Saúl A. and Haghverdi, Esfandiar
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Mathematics - Combinatorics ,11B75, 18C40 - Abstract
Motivated by the definition of Freiman homomorphism we explore the possibilities of formulating some basic notions and techniques of additive combinatorics in a categorical language. We show that additive sets and Freiman homomorphisms form a category and we study several limit and colimit constructions in this, and in an interesting subcategory of this category. Moreover, we study the additive structure of these (co)limit objects using additive doubling constant. We relate this category to that of finite sets and mappings, and that of abelian groups and group homomorphisms. We show that the Konyagin \& Lev result on universal ambient groups is an instance of adjunction., Comment: 16 pages, 4 diagrams
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- 2025
8. Spin and Orbital Rashba effects at the Ni/HfO$_2$ interface
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Pezo, Armando, Saul, Andrés, Manchon, Aurélien, and Arras, Rémi
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Condensed Matter - Materials Science - Abstract
We predict the giant ferroelectric control of interfacial properties of Ni/HfO2, namely, (i) the magnetocrystalline anisotropy and (ii) the inverse spin and orbital Rashba effects. The reversible control of magnetic properties using electric gating is a promising route to low-energy consumption magnetic devices, including memories and logic gates. Synthetic multiferroics, composed of a ferroelectric in proximity to a magnet, stand out as a promising platform for such devices. Using a combination of $ab$ $initio$ simulations and transport calculations, we demonstrate that reversing the electric polarization modulates the interface magnetocrystalline anisotropy from in-plane to out-of-plane. This modulation compares favorably with recent reports obtained upon electromigration induced by ionic gating. In addition, we find that the current-driven spin and orbital densities at the interface can be modulated by about 50% and 30%, respectively. This giant modulation of the spin-charge and orbit-charge conversion efficiencies opens appealing avenues for voltage-controlled spin- and orbitronics devices.
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- 2024
9. Birthmarks: Ergodicity Breaking Beyond Quantum Scars
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Graf, Anton M., Keski-Rahkonen, Joonas, Xiao, Mingxuan, Atwood, Saul, Lu, Zhongling, Chen, Siyuan, and Heller, Eric J.
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Quantum Physics - Abstract
One manifestation of classical ergodicity is a complete loss of memory of the initial conditions due to the eventual uniform exploration of phase space. In quantum versions of the same systems, classical ergodic traits can be broken. Here, we extend the concept of quantum scars in new directions, more focused on ergodicity and infinite time averages than individual eigenstates. We specifically establish a union of short and long-term enhancements in terms of a \emph{quantum birthmark} (QB). Subsequently, we show (1) that the birth and early evolution of a nonstationary state is remembered forever in infinite time averages, and (2) that early recurrences in the autocorrelation function inevitably lead to nonergodic flow over infinite times. We recount here that phase space cannot be explored ergodically if there are early recurrences (well before the Heisenberg time) in the autocorrelation of the initial nonstationary quantum state. Employing random matrix theory, we show that QB extends beyond individual states to entire subspaces or ``{\it birthplaces}" in Hilbert space. Finally, we visualize scar-amplified QBs unveiled within the time-averaged probability density of a wavepacket in a stadium system. By transcending the quantum scarring, QB delivers a new paradigm for understanding the elusive quantum nature of ergodicity.
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- 2024
10. Investing in Custodial Grandparents: Cost Analysis of the Social Intelligence Program
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D. Max Crowley, Ashley M. Tate, Yoon Sun Hur, Saul Castro, Carol M. Musil, Megan L. Dolbin-MacNab, Patrick O'Neill, Frank J. Infurna, and Gregory Smith
- Abstract
Rising child welfare costs and a desire to keep kids out of the system have encouraged the use of kinship care--of which custodial grandparents make up the majority of caregivers. Unfortunately, custodial grandparents report greater needs for social and emotional support to successfully care for their grandchildren. Yet, the resources required to provide preventive social-emotional support to these families are unknown. In the wake of the Family First Act and other policy actions to expand preventive services, we undertake a cost analysis of the social intelligence training (SIT) within a randomized controlled trial spanning 48 states of the United States of America. Estimated implementation costs were $90,638 (CI $45,254-186,998) which equated to $255 (CI $127-526) per participant. This dual-generation online approach offers key lessons into not only how to resource social-emotional learning (SEL) prevention for custodial grandparents--but also sheds light on how we might provide universal supports to this population. Child welfare system costs have risen to over $33 billion dollars a year--with nearly half of all spending being the result of out-of-home placement (Rosinsky et al., 2021) Child Welfare Financing SFY 2018: A survey of federal, state, and local expenditures. https://www.childtrends.org/wp-content/uploads/2021/05/ChildWelfareFinancing_ChildTrends_March2021.pdf). Practitioners, policymakers, and child advocates are seeking solutions for how to both better protect children and manage these growing public costs (Ringel et al., 2018). Improving child welfare outcomes: Balancing investments in prevention and treatment. Rand health quarterly, 7(4)). Further, many extended families seek ways to keep children out of the "system" when parents are unable to care for their offspring (Lin, Children and Youth Services Review 93:203-216, 2018). A strategy used by all of these groups is the use of kinship care arrangements where extended family provides formal or informal care of children. Several important benefits are recognized from kinship care, including providing connections to family members, communities, and culture. Yet, little is known about how social-emotional supports could enhance kinship arrangements, and to date, no studies have systematically evaluated the costs of such supports. In this context, we conduct a cost analysis of such a program--known as social intelligence training.
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- 2024
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11. Atomistic Origins of Conductance Switching in an ε-Cu0.9V2O5 Neuromorphic Single Crystal Oscillator.
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Ponis, John, Jerla, Nicholas, Agbeworvi, George, Perez-Beltran, Saul, Kumar, Nitin, Ashen, Kenna, Li, Jialu, Wang, Edrick, Smeaton, Michelle, Jardali, Fatme, Chakraborty, Sarbajeet, Shamberger, Patrick, Jungjohann, Katherine, Weiland, Conan, Jaye, Cherno, Ma, Lu, Fischer, Daniel, Guo, Jinghua, Sambandamurthy, G, Qian, Xiaofeng, and Banerjee, Sarbajit
- Abstract
Building artificial neurons and synapses is key to achieving the promise of energy efficiency and acceleration envisioned for brain-inspired information processing. Emulating the spiking behavior of biological neurons in physical materials requires precise programming of conductance nonlinearities. Strong correlated solid-state compounds exhibit pronounced nonlinearities such as metal-insulator transitions arising from dynamic electron-electron and electron-lattice interactions. However, a detailed understanding of atomic rearrangements and their implications for electronic structure remains obscure. In this work, we unveil discontinuous conductance switching from an antiferromagnetic insulator to a paramagnetic metal in ε-Cu0.9V2O5. Distinctively, fashioning nonlinear dynamical oscillators from entire millimeter-sized crystals allows us to map the structural transformations underpinning conductance switching at an atomistic scale using single-crystal X-ray diffraction. We observe superlattice ordering of Cu ions between [V4O10] layers at low temperatures, a direct result of interchain Cu-ion migration and intrachain reorganization. The resulting charge and spin ordering along the vanadium oxide framework stabilizes an insulating state. Using X-ray absorption and emission spectroscopies, assigned with the aid of electronic structure calculations and measurements of partially and completely decuprated samples, we find that Cu 3d and V 3d orbitals are closely overlapped near the Fermi level. The filling and overlap of these states, specifically the narrowing/broadening of V 3dxy states near the Fermi level, mediate conductance switching upon Cu-ion rearrangement. Understanding the mechanisms of conductance nonlinearities in terms of ion motion along specific trajectories can enable the atomistic design of neuromorphic active elements through strategies such as cointercalation and site-selective modification.
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- 2024
12. A gravitational wave detectable candidate Type Ia supernova progenitor
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Chickles, Emma T., Burdge, Kevin B., Chakraborty, Joheen, Dhillon, Vik S., Draghis, Paul, Hughes, Scott A., Munday, James, Rappaport, Saul A., Tonry, John, Bauer, Evan, Brown, Alex, Castro, Noel, Chakrabarty, Deepto, Dyer, Martin, El-Badry, Kareem, Frebel, Anna, Furesz, Gabor, Garbutt, James, Green, Matthew J., Householder, Aaron, Jarvis, Daniel, Kara, Erin, Kennedy, Mark R., Kerry, Paul, Littlefair, Stuart P, McCormac, James, Mo, Geoffrey, Ng, Mason, Parsons, Steven, Pelisoli, Ingrid, Pike, Eleanor, Prince, Thomas A., Ricker, George R., van Roestel, Jan, Sahman, David, Shen, Ken J., Simcoe, Robert A., Tremblay, Pier-Emmanuel, Vanderburg, Andrew, and Wong, Tin Long Sunny
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
Type Ia supernovae, critical for studying cosmic expansion, arise from thermonuclear explosions of white dwarfs, but their precise progenitor pathways remain unclear. Growing evidence supports the ``double-degenerate'' scenario, where two white dwarfs interact. The absence of other companion types capable of explaining the observed Ia rate, along with observations of hyper-velocity white dwarfs interpreted as surviving companions of such systems provide compelling evidence in favor of this scenario. Upcoming millihertz gravitational wave observatories like the Laser Interferometer Space Antenna (LISA) are expected to detect thousands of double-degenerate systems, though the most compact known candidate Ia progenitors produce only marginally detectable gravitational wave signals. Here, we report observations of ATLAS J1138-5139, a binary white dwarf system with an orbital period of 28 minutes. Our analysis reveals a 1 solar mass carbon-oxygen white dwarf accreting from a helium-core white dwarf. Given its mass, the accreting carbon-oxygen white dwarf is poised to trigger a typical-luminosity Type Ia supernova within a few million years, or to evolve into a stably mass-transferring AM CVn system. ATLAS J1138-5139 provides a rare opportunity to calibrate binary evolution models by directly comparing observed orbital parameters and mass transfer rates closer to merger than any previously identified candidate Type Ia progenitor. Its compact orbit ensures detectability by LISA, demonstrating the potential of millihertz gravitational wave observatories to reveal a population of Type Ia progenitors on a Galactic scale, paving the way for multi-messenger studies offering insights into the origins of these cosmologically significant explosions., Comment: 40 pages, 7 figures, 2 tables
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- 2024
13. Multi-Agent Best Arm Identification in Stochastic Linear Bandits
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Agrawal, Sanjana and Blanco, Saúl A.
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Computer Science - Machine Learning ,93E35 ,I.2.6 - Abstract
We study the problem of collaborative best-arm identification in stochastic linear bandits under a fixed-budget scenario. In our learning model, we consider multiple agents connected through a star network or a generic network, interacting with a linear bandit instance in parallel. The objective of the agents is to collaboratively learn the best arm of the given bandit instance with the help of a central server while minimizing the probability of error in best arm estimation. For this purpose, we devise the algorithms MaLinBAI-Star and MaLinBAI-Gen for star networks and generic networks respectively. Both algorithms employ an Upper-Confidence-Bound approach where agents share their knowledge through the central server during each communication round. We demonstrate, both theoretically and empirically, that our algorithms enjoy exponentially decaying probability of error in the allocated time budget. Furthermore, experimental results based on synthetic and real-world data validate the effectiveness of our algorithms over the existing multi-agent algorithms.
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- 2024
14. Expanding the ultracompacts: gravitational wave-driven mass transfer in the shortest-period binaries with accretion disks
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Chakraborty, Joheen, Burdge, Kevin B., Rappaport, Saul A., Munday, James, Chen, Hai-Liang, Rodríguez-Gil, Pablo, Dhillon, V. S., Hughes, Scott A., Nelemans, Gijs, Kara, Erin, Bellm, Eric C., Brown, Alex J., Segura, Noel Castro, Chen, Tracy X., Chickles, Emma, Dyer, Martin J., Dekany, Richard, Drake, Andrew J., Garbutt, James, Graham, Matthew J., Green, Matthew J., Jarvis, Dan, Kennedy, Mark R., Kerry, Paul, Kulkarni, S. R., Littlefair, Stuart P., Mahabal, Ashish A., Masci, Frank J., McCormac, James, Parsons, Steven G., Pelisoli, Ingrid, Pike, Eleanor, Prince, Thomas A., Riddle, Reed, van Roestel, Jan, Sahman, Dave, Wold, Avery, and Wong, Tin Long Sunny
- Subjects
Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Solar and Stellar Astrophysics - Abstract
We report the discovery of three ultracompact binary white dwarf systems hosting accretion disks, with orbital periods of 7.95, 8.68, and 13.15 minutes. This significantly augments the population of mass-transferring binaries at the shortest periods, and provides the first evidence that accretors in ultracompacts can be dense enough to host accretion disks even below 10 minutes (where previously only direct-impact accretors were known). In the two shortest-period systems, we measured changes in the orbital periods driven by the combined effect of gravitational wave emission and mass transfer; we find $\dot{P}$ is negative in one case, and positive in the other. This is only the second system measured with a positive $\dot{P}$, and it the most compact binary known that has survived a period minimum. Using these systems as examples, we show how the measurement of $\dot{P}$ is a powerful tool in constraining the physical properties of binaries, e.g. the mass and mass-radius relation of the donor stars. We find that the chirp masses of ultracompact binaries at these periods seem to cluster around $\mathcal{M}_c \sim 0.3 M_\odot$, perhaps suggesting a common origin for these systems or a selection bias in electromagnetic discoveries. Our new systems are among the highest-amplitude known gravitational wave sources in the millihertz regime, providing exquisite opportunity for multi-messenger study with future space-based observatories such as \textit{LISA} and TianQin; we discuss how such systems provide fascinating laboratories to study the unique regime where the accretion process is mediated by gravitational waves., Comment: Accepted for publication in ApJ
- Published
- 2024
15. Overtones and Nonlinearities in Binary Black Hole Ringdowns
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Giesler, Matthew, Ma, Sizheng, Mitman, Keefe, Oshita, Naritaka, Teukolsky, Saul A., Boyle, Michael, Deppe, Nils, Kidder, Lawrence E., Moxon, Jordan, Nelli, Kyle C., Pfeiffer, Harald P., Scheel, Mark A., Throwe, William, and Vu, Nils L.
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General Relativity and Quantum Cosmology - Abstract
Using high-accuracy numerical relativity waveforms, we confirm the presence of numerous overtones of the $\ell=2$, $m=2$ quasinormal mode early in the ringdown of binary black hole mergers. We do this by demonstrating the stability of the mode amplitudes at different fit times, ruling out the possibility that a linear superposition of modes unphysically fits a highly nonlinear part of the waveform. We also find a number of previously unidentified subdominant second-order quasinormal modes in the $(2,2)$ mode. Even though these modes are mathematically nonlinear, they nevertheless confirm the validity of perturbation theory as a good approximation for describing much of the ringdown., Comment: 17 pages, 14 figures
- Published
- 2024
16. Tidally distorted stars are triaxial pulsators
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Fuller, Jim, Rappaport, Saul, Jayaraman, Rahul, Kurtz, Don, and Handler, Gerald
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Astrophysics - Solar and Stellar Astrophysics - Abstract
Stars in close binaries are tidally distorted, and this has a strong effect on their pulsation modes. We compute the mode frequencies and geometries of tidally distorted stars using perturbation theory, accounting for the effects of the Coriolis force and the coupling between different azimuthal orders $m$ of a multiplet induced by the tidal distortion. For tidally coupled dipole pressure modes, the tidal coupling dominates over the Coriolis force and the resulting pulsations are ``triaxial", with each of the three modes in a multiplet ``tidally tilted" to be aligned with the one of the three principal axes of the star. The observed amplitudes and phases of the dipole modes aligned orthogonal to the spin axis are modulated throughout the orbit, producing doublets in the power spectrum that are spaced by exactly twice the orbital frequency. Quadrupole modes have similar but slightly more complex behavior. This amplitude modulation allows for mode identification which can potentially enable detailed asteroseismic analyses of tidally tilted pulsators. Pressure modes should exhibit this behavior in stellar binaries close enough to be tidally synchronized, while gravity modes should remain aligned with the star's spin axis. We discuss applications to various types of pulsating stars, and the relationship between tidal tilting of pulsations and the ``single-sided" pulsations sometimes observed in very tidally distorted stars., Comment: Submitted to ApJ, comments welcome!
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- 2024
17. Hopfield-Fenchel-Young Networks: A Unified Framework for Associative Memory Retrieval
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Santos, Saul, Niculae, Vlad, McNamee, Daniel, and Martins, André F. T.
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Computer Science - Machine Learning - Abstract
Associative memory models, such as Hopfield networks and their modern variants, have garnered renewed interest due to advancements in memory capacity and connections with self-attention in transformers. In this work, we introduce a unified framework-Hopfield-Fenchel-Young networks-which generalizes these models to a broader family of energy functions. Our energies are formulated as the difference between two Fenchel-Young losses: one, parameterized by a generalized entropy, defines the Hopfield scoring mechanism, while the other applies a post-transformation to the Hopfield output. By utilizing Tsallis and norm entropies, we derive end-to-end differentiable update rules that enable sparse transformations, uncovering new connections between loss margins, sparsity, and exact retrieval of single memory patterns. We further extend this framework to structured Hopfield networks using the SparseMAP transformation, allowing the retrieval of pattern associations rather than a single pattern. Our framework unifies and extends traditional and modern Hopfield networks and provides an energy minimization perspective for widely used post-transformations like $\ell_2$-normalization and layer normalization-all through suitable choices of Fenchel-Young losses and by using convex analysis as a building block. Finally, we validate our Hopfield-Fenchel-Young networks on diverse memory recall tasks, including free and sequential recall. Experiments on simulated data, image retrieval, multiple instance learning, and text rationalization demonstrate the effectiveness of our approach., Comment: 49 pages, 14 figures. arXiv admin note: text overlap with arXiv:2402.13725
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- 2024
18. EigenVI: score-based variational inference with orthogonal function expansions
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Cai, Diana, Modi, Chirag, Margossian, Charles C., Gower, Robert M., Blei, David M., and Saul, Lawrence K.
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Statistics - Machine Learning ,Computer Science - Machine Learning ,Statistics - Computation - Abstract
We develop EigenVI, an eigenvalue-based approach for black-box variational inference (BBVI). EigenVI constructs its variational approximations from orthogonal function expansions. For distributions over $\mathbb{R}^D$, the lowest order term in these expansions provides a Gaussian variational approximation, while higher-order terms provide a systematic way to model non-Gaussianity. These approximations are flexible enough to model complex distributions (multimodal, asymmetric), but they are simple enough that one can calculate their low-order moments and draw samples from them. EigenVI can also model other types of random variables (e.g., nonnegative, bounded) by constructing variational approximations from different families of orthogonal functions. Within these families, EigenVI computes the variational approximation that best matches the score function of the target distribution by minimizing a stochastic estimate of the Fisher divergence. Notably, this optimization reduces to solving a minimum eigenvalue problem, so that EigenVI effectively sidesteps the iterative gradient-based optimizations that are required for many other BBVI algorithms. (Gradient-based methods can be sensitive to learning rates, termination criteria, and other tunable hyperparameters.) We use EigenVI to approximate a variety of target distributions, including a benchmark suite of Bayesian models from posteriordb. On these distributions, we find that EigenVI is more accurate than existing methods for Gaussian BBVI., Comment: 25 pages, 9 figures. Advances in Neural Information Processing Systems (NeurIPS), 2024
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- 2024
19. Is Function Similarity Over-Engineered? Building a Benchmark
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Saul, Rebecca, Liu, Chang, Fleischmann, Noah, Zak, Richard, Micinski, Kristopher, Raff, Edward, and Holt, James
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Computer Science - Machine Learning ,Computer Science - Cryptography and Security - Abstract
Binary analysis is a core component of many critical security tasks, including reverse engineering, malware analysis, and vulnerability detection. Manual analysis is often time-consuming, but identifying commonly-used or previously-seen functions can reduce the time it takes to understand a new file. However, given the complexity of assembly, and the NP-hard nature of determining function equivalence, this task is extremely difficult. Common approaches often use sophisticated disassembly and decompilation tools, graph analysis, and other expensive pre-processing steps to perform function similarity searches over some corpus. In this work, we identify a number of discrepancies between the current research environment and the underlying application need. To remedy this, we build a new benchmark, REFuSE-Bench, for binary function similarity detection consisting of high-quality datasets and tests that better reflect real-world use cases. In doing so, we address issues like data duplication and accurate labeling, experiment with real malware, and perform the first serious evaluation of ML binary function similarity models on Windows data. Our benchmark reveals that a new, simple basline, one which looks at only the raw bytes of a function, and requires no disassembly or other pre-processing, is able to achieve state-of-the-art performance in multiple settings. Our findings challenge conventional assumptions that complex models with highly-engineered features are being used to their full potential, and demonstrate that simpler approaches can provide significant value., Comment: To appear in the 38th Conference on Neural Information Processing Systems (NeurIPS 2024) Track on Datasets and Benchmarks
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- 2024
20. On the generalised Saxl graphs of permutation groups
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Freedman, Saul D., Huang, Hong Yi, Lee, Melissa, and Rekvényi, Kamilla
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Mathematics - Group Theory - Abstract
A base for a finite permutation group $G \le \mathrm{Sym}(\Omega)$ is a subset of $\Omega$ with trivial pointwise stabiliser in $G$, and the base size of $G$ is the smallest size of a base for $G$. Motivated by the interest in groups of base size two, Burness and Giudici introduced the notion of the Saxl graph. This graph has vertex set $\Omega$, with edges between elements if they form a base for $G$. We define a generalisation of this graph that encodes useful information about $G$ whenever $b(G) \ge 2$: here, the edges are the pairs of elements of $\Omega$ that can be extended to bases of size $b(G)$. In particular, for primitive groups, we investigate the completeness and arc-transitivity of the generalised graph, and the generalisation of Burness and Giudici's Common Neighbour Conjecture on the original Saxl graph., Comment: 35 pages; minor formatting changes
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- 2024
21. Batch, match, and patch: low-rank approximations for score-based variational inference
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Modi, Chirag, Cai, Diana, and Saul, Lawrence K.
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Statistics - Machine Learning ,Computer Science - Machine Learning ,Statistics - Computation - Abstract
Black-box variational inference (BBVI) scales poorly to high dimensional problems when it is used to estimate a multivariate Gaussian approximation with a full covariance matrix. In this paper, we extend the batch-and-match (BaM) framework for score-based BBVI to problems where it is prohibitively expensive to store such covariance matrices, let alone to estimate them. Unlike classical algorithms for BBVI, which use gradient descent to minimize the reverse Kullback-Leibler divergence, BaM uses more specialized updates to match the scores of the target density and its Gaussian approximation. We extend the updates for BaM by integrating them with a more compact parameterization of full covariance matrices. In particular, borrowing ideas from factor analysis, we add an extra step to each iteration of BaM -- a patch -- that projects each newly updated covariance matrix into a more efficiently parameterized family of diagonal plus low rank matrices. We evaluate this approach on a variety of synthetic target distributions and real-world problems in high-dimensional inference.
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- 2024
22. A Cranial-Feature-Based Registration Scheme for Robotic Micromanipulation Using a Microscopic Stereo Camera System
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Lin, Xiaofeng, Pérez, Saúl Alexis Heredia, and Harada, Kanako
- Subjects
Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Robotics - Abstract
Biological specimens exhibit significant variations in size and shape, challenging autonomous robotic manipulation. We focus on the mouse skull window creation task to illustrate these challenges. The study introduces a microscopic stereo camera system (MSCS) enhanced by the linear model for depth perception. Alongside this, a precise registration scheme is developed for the partially exposed mouse cranial surface, employing a CNN-based constrained and colorized registration strategy. These methods are integrated with the MSCS for robotic micromanipulation tasks. The MSCS demonstrated a high precision of 0.10 mm $\pm$ 0.02 mm measured in a step height experiment and real-time performance of 30 FPS in 3D reconstruction. The registration scheme proved its precision, with a translational error of 1.13 mm $\pm$ 0.31 mm and a rotational error of 3.38$^{\circ}$ $\pm$ 0.89$^{\circ}$ tested on 105 continuous frames with an average speed of 1.60 FPS. This study presents the application of a MSCS and a novel registration scheme in enhancing the precision and accuracy of robotic micromanipulation in scientific and surgical settings. The innovations presented here offer automation methodology in handling the challenges of microscopic manipulation, paving the way for more accurate, efficient, and less invasive procedures in various fields of microsurgery and scientific research., Comment: Accepted by Advanced Robotics, Vol. 38, Issue 21
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- 2024
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23. Variational Inference in Location-Scale Families: Exact Recovery of the Mean and Correlation Matrix
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Margossian, Charles C. and Saul, Lawrence K.
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Statistics - Machine Learning ,Computer Science - Machine Learning ,Statistics - Computation - Abstract
Given an intractable target density $p$, variational inference (VI) attempts to find the best approximation $q$ from a tractable family $Q$. This is typically done by minimizing the exclusive Kullback-Leibler divergence, $\text{KL}(q||p)$. In practice, $Q$ is not rich enough to contain $p$, and the approximation is misspecified even when it is a unique global minimizer of $\text{KL}(q||p)$. In this paper, we analyze the robustness of VI to these misspecifications when $p$ exhibits certain symmetries and $Q$ is a location-scale family that shares these symmetries. We prove strong guarantees for VI not only under mild regularity conditions but also in the face of severe misspecifications. Namely, we show that (i) VI recovers the mean of $p$ when $p$ exhibits an \textit{even} symmetry, and (ii) it recovers the correlation matrix of $p$ when in addition~$p$ exhibits an \textit{elliptical} symmetry. These guarantees hold for the mean even when $q$ is factorized and $p$ is not, and for the correlation matrix even when~$q$ and~$p$ behave differently in their tails. We analyze various regimes of Bayesian inference where these symmetries are useful idealizations, and we also investigate experimentally how VI behaves in their absence.
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- 2024
24. AI-based particle track identification in scintillating fibres read out with imaging sensors
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Bührer, Noemi, Alonso-Monsalve, Saúl, Franks, Matthew, Dieminger, Till, and Sgalaberna, Davide
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Computer Science - Machine Learning ,High Energy Physics - Experiment ,Physics - Instrumentation and Detectors - Abstract
This paper presents the development and application of an AI-based method for particle track identification using scintillating fibres read out with imaging sensors. We propose a variational autoencoder (VAE) to efficiently filter and identify frames containing signal from the substantial data generated by SPAD array sensors. Our VAE model, trained on purely background frames, demonstrated a high capability to distinguish frames containing particle tracks from background noise. The performance of the VAE-based anomaly detection was validated with experimental data, demonstrating the method's ability to efficiently identify relevant events with rapid processing time, suggesting a solid prospect for deployment as a fast inference tool on hardware for real-time anomaly detection. This work highlights the potential of combining advanced sensor technology with machine learning techniques to enhance particle detection and tracking., Comment: 19 pages, 9 figures
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- 2024
25. Eccentricity Reduction for Quasicircular Binary Evolutions
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Habib, Sarah, Scheel, Mark, and Teukolsky, Saul
- Subjects
General Relativity and Quantum Cosmology - Abstract
Simulation of quasicircular compact binaries is a major goal in numerical relativity, as they are expected to constitute most gravitational wave observations. However, given that orbital eccentricity is not well-defined in general relativity, providing initial data for such binaries is a challenge for numerical simulations. Most numerical relativity codes obtain initial conditions for low-eccentricity binary simulations by iterating over a sequence of short simulations -- measuring eccentricity mid-evolution and correcting the initial data parameters accordingly. Eccentricity measurement depends on a numerically challenging nonlinear fit to an estimator model, and the resulting eccentricity estimate is extremely sensitive to small changes in how the fit is performed. We have developed an improved algorithm that produces more consistent measurements of eccentricity relative to the time window chosen for fitting. The primary innovations are the use of the nonlinear optimization algorithm, variable projection, in place of more conventional routines, an initial fit parameter guess taken from the trajectory frequency spectrum, and additional frequency processing of the trajectory data prior to fitting., Comment: 12 pages, 8 figures
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- 2024
26. TIC 290061484: A Triply Eclipsing Triple System with the Shortest Known Outer Period of 24.5 Days
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Kostov, Veselin B., Rappaport, Saul A., Borkovits, Tamas, Powell, Brian P., Gagliano, Robert, Omohundro, Mark, Biro, Imre B., Moe, Max, Howell, Steve B., Mitnyan, Tibor, Clark, Catherine A., Kristiansen, Martti H., Terentev, Ivan A., Schwengeler, Hans M., Pal, Andras, and Vanderburg, Andrew
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Astrophysics - Solar and Stellar Astrophysics - Abstract
We have discovered a triply eclipsing triple-star system, TIC 290061484, with the shortest known outer period, Pout, of only 24.5 days. This "eclipses" the previous record set by lambda Tauri at 33.02 days, which held for 68 yr. The inner binary, with an orbital period of Pin = 1.8 days, produces primary and secondary eclipses and exhibits prominent eclipse timing variations with the same periodicity as the outer orbit. The tertiary star eclipses, and is eclipsed by, the inner binary with pronounced asymmetric profiles. The inclinations of both orbits evolve on observable timescales such that the third-body eclipses exhibit dramatic depth variations in TESS data. A photodynamical model provides a complete solution for all orbital and physical parameters of the triple system, showing that the three stars have masses of 6.85, 6.11, and 7.90 MSun, radii near those corresponding to the main sequence, and Teff in the range of 21,000-23,700 K. Remarkably, the model shows that the triple is in fact a subsystem of a hierarchical 2+1+1 quadruple with a distant fourth star. The outermost star has a period of ~3200 days and a mass comparable to the stars in the inner triple. In ~20 Myr, all three components of the triple subsystem will merge, undergo a Type II supernova explosion, and leave a single remnant neutron star. At the time of writing, TIC 290061484 is the most compact triple system and one of the tighter known compact triples (i.e., Pout/Pin = 13.7)., Comment: 27 pages, 13 figures, 6 tables
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- 2024
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27. FlexLMM: a Nextflow linear mixed model framework for GWAS
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Pierotti, Saul, Fitzgerald, Tomas, and Birney, Ewan
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Quantitative Biology - Genomics - Abstract
Summary: Linear mixed models are a commonly used statistical approach in genome-wide association studies when population structure is present. However, naive permutations to empirically estimate the null distribution of a statistic of interest are not appropriate in the presence of population structure, because the samples are not exchangeable with each other. For this reason we developed FlexLMM, a Nextflow pipeline that runs linear mixed models while allowing for flexibility in the definition of the exact statistical model to be used. FlexLMM can also be used to set a significance threshold via permutations, thanks to a two-step process where the population structure is first regressed out, and only then are the permutations performed. We envision this pipeline will be particularly useful for researchers working on multi-parental crosses among inbred lines of model organisms or farm animals and plants. Availability and implementation: The source code and documentation for the FlexLMM is available at https://github.com/birneylab/flexlmm., Comment: 6 pages, 1 figure
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- 2024
28. Simulating binary black hole mergers using discontinuous Galerkin methods
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Lovelace, Geoffrey, Nelli, Kyle C., Deppe, Nils, Vu, Nils L., Throwe, William, Bonilla, Marceline S., Carpenter, Alexander, Kidder, Lawrence E., Macedo, Alexandra, Scheel, Mark A., Afram, Azer, Boyle, Michael, Ceja, Andrea, Giesler, Matthew, Habib, Sarah, Jones, Ken Z., Kumar, Prayush, Lara, Guillermo, Melchor, Denyz, Mendes, Iago B., Mitman, Keefe, Morales, Marlo, Moxon, Jordan, O'Shea, Eamonn, Pannone, Kyle, Pfeiffer, Harald P., Ramirez-Aguilar, Teresita, Sanchez, Jennifer, Tellez, Daniel, Teukolsky, Saul A., and Wittek, Nikolas A.
- Subjects
General Relativity and Quantum Cosmology - Abstract
Binary black holes are the most abundant source of gravitational-wave observations. Gravitational-wave observatories in the next decade will require tremendous increases in the accuracy of numerical waveforms modeling binary black holes, compared to today's state of the art. One approach to achieving the required accuracy is using spectral-type methods that scale to many processors. Using the SpECTRE numerical-relativity code, we present the first simulations of a binary black hole inspiral, merger, and ringdown using discontinuous Galerkin methods. The efficiency of discontinuous Galerkin methods allows us to evolve the binary through ~18 orbits at reasonable computational cost. We then use SpECTRE's Cauchy Characteristic Evolution (CCE) code to extract the gravitational waves at future null infinity. The open-source nature of SpECTRE means this is the first time a spectral-type method for simulating binary black hole evolutions is available to the entire numerical-relativity community., Comment: 32 pages, 12 figures, 28 ancillary input files
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- 2024
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29. Quantum thermalization of translation-invariant systems at high temperature
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Pilatowsky-Cameo, Saúl and Choi, Soonwon
- Subjects
Quantum Physics ,Condensed Matter - Statistical Mechanics - Abstract
Quantum thermalization describes how closed quantum systems can effectively reach thermal equilibrium, resolving the apparent incongruity between the reversibility of Schr\"odinger's equation and the irreversible entropy growth dictated by the second law of thermodynamics. Despite its ubiquity and conceptual significance, a complete proof of quantum thermalization has remained elusive for several decades. Here, we prove that quantum thermalization must occur in any qubit system with local interactions satisfying three conditions: (i) high effective temperature, (ii) translation invariance, and (iii) no perfect resonances in the energy spectrum. Specifically, we show that a typical, initially unentangled pure state drawn from any ensemble with maximum entropy becomes locally indistinguishable from a Gibbs state upon unitary evolution. Our proof relies on a recent breakthrough in quantum information theory proving the separability of high-temperature thermal states, as well as on new technical results identifying sufficient conditions for quantum thermalization, whose applicability extends beyond our main result. Our work illustrates that statistical physics can be understood as an emergent phenomenon, explicitly derived from the first principles of quantum mechanics., Comment: 7 pages, 3 figures, 12 page supplement
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- 2024
30. TIC 435850195: The Second Tri-Axial, Tidally Tilted Pulsator
- Author
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Jayaraman, Rahul, Rappaport, Saul, Powell, Brian, Handler, Gerald, Omohundro, Mark, Gagliano, Robert, Kostov, Veselin, Fuller, Jim, Kurtz, Donald, Zhang, Valencia, and Ricker, George
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Astrophysics - Solar and Stellar Astrophysics - Abstract
The Transiting Exoplanet Survey Satellite (TESS) has enabled the discovery of numerous tidally tilted pulsators (TTPs), which are pulsating stars in close binaries where the presence of a tidal bulge has the effect of tilting the primary star's pulsation axes into the orbital plane. Recently, the modeling framework developed to analyze TTPs has been applied to the emerging class of tri-axial pulsators, which exhibit nonradial pulsations about three perpendicular axes. In this work, we report on the identification of the second-ever discovered tri-axial pulsator, with sixteen robustly-detected pulsation multiplets, of which fourteen are dipole doublets separated by 2$\nu_{\rm orb}$. We jointly fit the spectral energy distribution (SED) and TESS light curve of the star, and find that the primary is slightly evolved off the zero-age main sequence, while the less massive secondary still lies on the zero-age main sequence. Of the fourteen doublets, we associate eight with $Y_{10x}$ modes and six with novel $Y_{10y}$ modes. We exclude the existence of $Y_{11x}$ modes in this star and show that the observed pulsation modes must be $Y_{10y}$. We also present a toy model for the tri-axial pulsation framework in the context of this star. The techniques presented here can be utilized to rapidly analyze and confirm future tri-axial pulsator candidates., Comment: 19 pages, 11 figures, 4 tables. Accepted for publication in ApJ
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- 2024
31. Light-curve analysis and shape models of NEAs 7335, 7822, 154244 and 159402
- Author
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Rodríguez, Javier Rodríguez, Alonso, Enrique Díez, Álvarez, Santiago Iglesias, Fernández, Saúl Pérez, Roca, Alejandro Buendia, Díaz, Julia Fernández, Licandro, Javier, Alarcon, Miguel R., Serra-Ricart, Miquel, Pinilla-Alonso, Noemi, and Juez, Francisco Javier de Cos
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
In an attempt to further characterise the near-Earth asteroid (NEA) population we present 38 new light-curves acquired between September 2020 and November 2023 for NEAs (7335) 1989 JA, (7822) 1991 CS, (154244) 2002 KL6 and (159402) 1999 AP10, obtained from observations taken at the Teide Observatory (Tenerife, Spain). With these new observations along with archival data, we computed their first shape models and spin solutions by applying the light curve inversion method. The obtained rotation periods are in good agreement with those reported in previous works, with improved uncertainties. Additionally, besides the constant period models for (7335) 1989 JA, (7822) 1991 CS and (159402) 1999 AP10, our results for (154244) 2002 KL6 suggest that it could be affected by a Yarkovsky-O'Keefe-Radzievskii-Paddack acceleration with a value of $\upsilon \simeq -7 \times 10^{-9}$ rad d$^{-2}$. This would be one of the first detections of this effect slowing down an asteroid.
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- 2024
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32. Some novel constructions of optimal Gromov-Hausdorff-optimal correspondences between spheres
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Martín, Saúl Rodríguez
- Subjects
Mathematics - Metric Geometry ,51F99 - Abstract
In this article, as a first contribution, we provide alternative proofs of recent results by Harrison and Jeffs which determine the precise value of the Gromov-Hausdorff (GH) distance between the circle $\mathbb{S}^1$ and the $n$-dimensional sphere $\mathbb{S}^n$ (for any $n\in\mathbb{N}$) when endowed with their respective geodesic metrics. Additionally, we prove that the GH distance between $\mathbb{S}^3$ and $\mathbb{S}^4$ is equal to $\frac{1}{2}\arccos\left(\frac{-1}{4}\right)$, thus settling the case $n=3$ of a conjecture by Lim, M\'emoli and Smith., Comment: 32 pages, 12 figures
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- 2024
33. Modular flavored dark matter
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Baur, Alexander, Chen, Mu-Chun, Knapp-Perez, V., and Ramos-Sanchez, Saul
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High Energy Physics - Phenomenology ,High Energy Physics - Theory - Abstract
Discrete flavor symmetries have been an appealing approach for explaining the observed flavor structure, which is not justified in the Standard Model (SM). Typically, these models require a so-called flavon field in order to give rise to the flavor structure upon the breaking of the flavor symmetry by the vacuum expectation value (VEV) of the flavon. Generally, in order to obtain the desired vacuum alignment, a flavon potential that includes additional so-called driving fields is required. On the other hand, allowing the flavor symmetry to be modular leads to a structure where the couplings are all holomorphic functions that depend only on a complex modulus, thus greatly reducing the number of parameters in the model. We show that these elements can be combined to simultaneously explain the flavor structure and dark matter (DM) relic abundance. We present a modular model with flavon vacuum alignment that allows for realistic flavor predictions while providing a successful fermionic DM candidate., Comment: 24 pages, 7 figures, Added discussion on direct detection, results unchanged, matches version published in JHEP
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- 2024
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34. An inverse of Furstenberg's correspondence principle and applications to van der Corput sets
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Martín, Saúl Rodríguez
- Subjects
Mathematics - Group Theory ,Mathematics - Dynamical Systems ,28D15 (Primary) 37A05 (Secondary) - Abstract
In this article we give characterizations of the notions of van der Corput (vdC) set, nice vdC set and set of nice recurrence (defined below) in countable amenable groups. This allows us to prove that nice vdC sets are sets of nice recurrence and that vdC sets are independent of the F{\o}lner sequence used to define them, answering questions from Bergelson and Lesigne in the context of countable amenable groups. We also give a spectral characterization of vdC sets in abelian groups. The methods developed in this paper allow us to establish a converse to the Furstenberg correspondence principle. In addition, we introduce vdC sets in general non amenable groups and establish some basic properties of them, such as partition regularity. Several results in this paper, including the converse to Furstenberg's correspondence principle, have also been proved independently by Robin Tucker-Drob and Sohail Farhangi in their article `Van der Corput sets in amenable groups and beyond', which is being uploaded to arXiv simultaneously to this one., Comment: 31 pages
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- 2024
35. Perceptions of Parents/Caregivers about the Impact of Oral Conditions on the Quality of Life of Children and Adolescents with Autism Spectrum Disorder
- Author
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Stefania Werneck Procopio, Maisa Costa Tavares, Camila Faria Carrada, Flávia Almeida Ribeiro Scalioni, Rosangela Almeida Ribeiro, and Saul Martins Paiva
- Abstract
Purpose: To investigate the perceptions of parents/caregivers about the impact of oral conditions on the oral health-related quality of life (OHRQoL) of children/adolescents with autism spectrum disorder (ASD) compared to the perceptions of parents/caregivers of children/adolescents without ASD. Methods: A comparative cross-sectional study was conducted involving 80 children/adolescents with ASD three to 16 years of age matched by sex and age with 80 children/adolescents without ASD and their parents/caregivers. Clinical examinations were performed for the diagnosis of dental caries experience (DMFT/dmft), clinical consequences of untreated dental caries (PUFA/pufa), visible plaque (VPI), bleeding on probing (BPI), malocclusion and traumatic dental injury (TDI). Parents/caregivers answered a questionnaire addressing sociodemographic characteristics and the Brazilian version of the Parental-Caregiver Perceptions Questionnaire (P-CPQ), which measures OHRQoL from the perspective of parents/caregivers. Data analysis involved the Wilcoxon test, chi-squared test and Poisson regression. Results: Dental caries experience impacted OHRQoL in the group with ASD regarding the total P-CPQ score (p < 0.001) as well as the "oral symptoms" (p = 0.011) and "wellbeing" (p < 0.011) domains. No differences were found between the perceptions of parents/caregivers of children/adolescents with ASD and perceptions of parents/caregivers of children/adolescents without ASD (p = 0.721). Conclusion: Dental caries experience can have a negative impact on the OHRQoL of children/adolescents with ASD.
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- 2024
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36. Will DANCAVAS be the most important screening trial in the last 50 years?
- Author
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Dixit, Neal, Chau, Edward, and Schaefer, Saul
- Abstract
Screening trials for cardiovascular disease have not demonstrated a reduction in all-cause mortality. The Danish Cardiovascular Screening trial (DANCAVAS) involved men aged 65-74 years old who were randomized to an invitation to undergo screening or not. While the 5-year interim analysis did not show a statistically significant benefit in the primary outcome of all-cause mortality, HR 0.95 (CI 0.90-1.00), a sub-group analysis of men age 65-69 did show a lower hazard ratio of 0.89 (CI 0.83-0.96). Given the widening difference between screened and un-screened participants, as well as the benefit in younger subjects, it is likely that the next analysis will demonstrate a statistically-significant benefit of screening. In this commentary we argue why this trial will almost certainly become one of the most influential screening trials and why heeding its most important lesson, the use of coronary artery calcium scoring, has the potential to save countless lives.
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- 2024
37. Hitting the Gym: Reinforcement Learning Control of Exercise-Strengthened Biohybrid Robots in Simulation
- Author
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Schaffer, Saul, Pamu, Hima Hrithik, and Webster-Wood, Victoria A.
- Subjects
Computer Science - Robotics - Abstract
Animals can accomplish many incredible behavioral feats across a wide range of operational environments and scales that current robots struggle to match. One explanation for this performance gap is the extraordinary properties of the biological materials that comprise animals, such as muscle tissue. Using living muscle tissue as an actuator can endow robotic systems with highly desirable properties such as self-healing, compliance, and biocompatibility. Unlike traditional soft robotic actuators, living muscle biohybrid actuators exhibit unique adaptability, growing stronger with use. The dependency of a muscle's force output on its use history endows muscular organisms the ability to dynamically adapt to their environment, getting better at tasks over time. While muscle adaptability is a benefit to muscular organisms, it currently presents a challenge for biohybrid researchers: how does one design and control a robot whose actuators' force output changes over time? Here, we incorporate muscle adaptability into a many-muscle biohybrid robot design and modeling tool, leveraging reinforcement learning as both a co-design partner and system controller. As a controller, our learning agents coordinated the independent contraction of 42 muscles distributed on a lattice worm structure to successfully steer it towards eight distinct targets while incorporating muscle adaptability. As a co-design tool, our agents enable users to identify which muscles are important to accomplishing a given task. Our results show that adaptive agents outperform non-adaptive agents in terms of maximum rewards and training time. Together, these contributions can both enable the elucidation of muscle actuator adaptation and inform the design and modeling of adaptive, performant, many-muscle robots., Comment: 11 pages, 6 figures
- Published
- 2024
38. Some integer values in the spectra of burnt pancake graphs
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Blanco, Saúl A. and Buehrle, Charles
- Subjects
Mathematics - Combinatorics ,Computer Science - Discrete Mathematics ,05C50, 68R10 ,G.2.1 ,G.2.2 - Abstract
The burnt pancake graph, denoted by $\mathbb{BP}_n$, is formed by connecting signed permutations via prefix reversals. Here, we discuss some spectral properties of $\mathbb{BP}_n$. More precisely, we prove that the adjacency spectrum of $\mathbb{BP}_n$ contains all integer values in the set $\{0, 1, \ldots, n\}\setminus\{\left\lfloor n/2 \right\rfloor\}$., Comment: Fixed typos and other small changes. Final version to appear in Linear Algebra and its Applications
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- 2024
39. Electronic Structure and Kohn-Luttinger Superconductivity of Heavily-Doped Single-Layer Graphene
- Author
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Herrera, Saul, Parra-Martinez, Guillermo, Rosenzweig, Philipp, Matta, Bharti, Polley, Craig M., Kuster, Kathrin, Starke, Ulrich, Guinea, Francisco, Silva-Guillen, Jose Angel, Naumis, Gerardo G., and Pantaleon, Pierre A.
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
The existence of superconductivity (SC) in graphene appears to be established in both twisted and non-twisted multilayers. However, whether their building block, single-layer graphene (SLG), can also host SC remains an open question. Earlier theoretical works predicted that SLG could become a chiral d-wave superconductor driven by electronic interactions when doped to its van Hove singularity, but questions such as whether the d-wave SC survives the strong band renormalizations seen in experiments, its robustness against the source of doping, or if it will occur at any reasonable critical temperature (Tc) have remained difficult to answer, in part due to uncertainties in model parameters. In this study, we adopt a random-phase approximation framework based on a Kohn-Luttinger-like mechanism to investigate SC in heavily-doped SLG. We predict that robust d+id topological SC could arise in SLG doped by Tb, with a Tc up to 600 mK. We also investigate the possibility of realizing d-wave SC by employing other dopants, such as Li or Cs. The structural models have been derived from angle-resolved photoemission spectroscopy measurements on Tb-doped graphene and first-principles calculations for Cs and Li doping. We find that dopants that change the lattice symmetry of SLG are detrimental to the d-wave state. The stability of the d-wave SC predicted here in Tb-doped SLG could provide a valuable insight for guiding future experimental efforts aimed at exploring topological superconductivity in monolayer graphene., Comment: 14 pages, 6 figures. Comments are very welcome
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- 2024
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40. Automated determination of the end time of junk radiation in binary black hole simulations
- Author
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Pretto, Isabella G., Scheel, Mark A., and Teukolsky, Saul A.
- Subjects
General Relativity and Quantum Cosmology - Abstract
When numerically solving Einstein's equations for the evolution of binary black holes, physical imperfections in the initial data manifest as a transient, high-frequency pulse of ''junk radiation.'' This unphysical signal must be removed before the waveform can be used. Improvements in the efficiency of numerical simulations now allow waveform catalogs containing thousands of waveforms to be produced. Thus, an automated procedure for identifying junk radiation is required. To this end, we present a new algorithm based on the empirical mode decomposition (EMD) from the Hilbert-Huang transform. This approach allows us to isolate and measure the high-frequency oscillations present in the measured irreducible masses of the black holes. The decay of these oscillations allows us to estimate the time from which the junk radiation can be ignored. To make this procedure more precise, we propose three distinct threshold criteria that specify how small the contribution of junk radiation has to be before it can be considered negligible. We apply this algorithm to 3403 BBH simulations from the SXS catalog to find appropriate values for the thresholds in the three criteria. We find that this approach yields reliable decay time estimates, i.e., when to consider the simulation physical, for over 98.6% of the simulations studied. This demonstrates the efficacy of the EMD as a suitable tool to automatically isolate and characterize junk radiation in the simulation of binary black hole systems.
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- 2024
41. Connecting essential triangulations II: via 2-3 moves only
- Author
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Kalelkar, Tejas, Schleimer, Saul, and Segerman, Henry
- Subjects
Mathematics - Geometric Topology ,57K31, 57Q15 - Abstract
In previous work we showed that for a manifold $M$, whose universal cover has infinitely many boundary components, the set of essential ideal triangulations of $M$ is connected via 2-3, 3-2, 0-2, and 2-0 moves. Here we show that this set is also connected via 2-3 and 3-2 moves alone, if we ignore those triangulations for which no 2-3 move preserves essentiality. If we also allow V-moves and their inverses then the full set of essential ideal triangulations of $M$ is once again connected. These results also hold if we replace essential triangulations with $L$-essential triangulations., Comment: 42 pages, 69 figures and subfigures. Version 2. We give a fuller discussion of isolated triangulations
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- 2024
42. Binary neutron star mergers using a discontinuous Galerkin-finite difference hybrid method
- Author
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Deppe, Nils, Foucart, Francois, Bonilla, Marceline S., Boyle, Michael, Corso, Nicholas J., Duez, Matthew D., Giesler, Matthew, Hébert, François, Kidder, Lawrence E., Kim, Yoonsoo, Kumar, Prayush, Legred, Isaac, Lovelace, Geoffrey, Most, Elias R., Moxon, Jordan, Nelli, Kyle C., Pfeiffer, Harald P., Scheel, Mark A., Teukolsky, Saul A., Throwe, William, and Vu, Nils L.
- Subjects
General Relativity and Quantum Cosmology - Abstract
We present a discontinuous Galerkin-finite difference hybrid scheme that allows high-order shock capturing with the discontinuous Galerkin method for general relativistic magnetohydrodynamics in dynamical spacetimes. We present several optimizations and stability improvements to our algorithm that allow the hybrid method to successfully simulate single, rotating, and binary neutron stars. The hybrid method achieves the efficiency of discontinuous Galerkin methods throughout almost the entire spacetime during the inspiral phase, while being able to robustly capture shocks and resolve the stellar surfaces. We also use Cauchy-Characteristic evolution to compute the first gravitational waveforms at future null infinity from binary neutron star mergers. The simulations presented here are the first successful binary neutron star inspiral and merger simulations using discontinuous Galerkin methods., Comment: 31 pages, 8 figures, minor wording updates
- Published
- 2024
43. Seasonal footprints on ecological time series and jumps in dynamic states of protein configurations from a non-linear forecasting method characterization
- Author
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Reyes, Leonardo, Campos, Kilver, Avendaño, Douglas, González-Paz, Lenin, Vivas, Alejandro, Alvarado, Ysaías J., and Flores, Saúl
- Subjects
Condensed Matter - Soft Condensed Matter ,Nonlinear Sciences - Adaptation and Self-Organizing Systems - Abstract
We have analyzed phenology data and protein configurations from molecular dynamics simulations with the nonlinear forecasting method proposed by May and Sugihara. Our primary focus in this work is to characterize the dynamic state of a system by quantifying prediction quality from data. Full plots of prediction quality as a function of dimensionality $E$ and forecasting time $T_p$, the two basic parameters of the method, give fast and valuable information about Complex Systems dynamics. We detect changes in protein dynamics due to mutations and, regarding ecology data, we show how cycles and {\it rhythms} of the environment manifests in parameter space $(E,T_p)$ for some species., Comment: 6 pages, 9 figures
- Published
- 2024
44. Increased serum GM-CSF at diagnosis of biliary atresia is associated with improved biliary drainage
- Author
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Taylor, Sarah A., Harpavat, Sanjiv, Gromer, Kyle D., Andreev, Victor, Loomes, Kathleen M., Bezerra, Jorge A., Jarasvaraparn, Chaowapong, Wang, Kasper, Horslen, Simon, Rosenthal, Philip, Teckman, Jeffrey, Valentino, Pamela L., Ng, Vicky L., Karpen, Saul J., Sokol, Ronald J., Alonso, Estella M., and Mack, Cara L.
- Published
- 2025
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45. Extracorporeal Membrane Oxygenation in Children with Pulmonary Atresia and Intact Ventricular Septum: Mortality and Associated Outcomes
- Author
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Flores, Saul, Loomba, Rohit S., Mastropietro, Christopher W., Cheung, Eva, Amula, Venugopal, Radman, Monique R., Kwiatkowski, David M., Puente, Bao N., Buckley, Jason R., Allen, Kiona Y., Karki, Karan B., Chiwane, Saurabh, Cashen, Katherine, Piggott, Kurt, Kapileshwarkar, Yamini, Gowda, Keshava M. N., Badheka, Aditya, Raman, Rahul, Zang, Huaiyu, Costello, John M., and Iliopoulos, Ilias
- Published
- 2025
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46. The Inadequate Oxygen Delivery Index and Its Correlation with Venous Saturation in the Pediatric Cardiac Intensive Care Unit
- Author
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Loomba, Rohit S., Villarreal, Enrique G., Flores, Saul, Farias, Juan S., and Constas, Alex
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- 2025
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47. RAS-mutant leukaemia stem cells drive clinical resistance to venetoclax
- Author
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Sango, Junya, Carcamo, Saul, Sirenko, Maria, Maiti, Abhishek, Mansour, Hager, Ulukaya, Gulay, Tomalin, Lewis E., Cruz-Rodriguez, Nataly, Wang, Tiansu, Olszewska, Malgorzata, Olivier, Emmanuel, Jaud, Manon, Nadorp, Bettina, Kroger, Benjamin, Hu, Feng, Silverman, Lewis, Chung, Stephen S., Wagenblast, Elvin, Chaligne, Ronan, Eisfeld, Ann-Kathrin, Demircioglu, Deniz, Landau, Dan A., Lito, Piro, Papaemmanuil, Elli, DiNardo, Courtney D., Hasson, Dan, Konopleva, Marina, and Papapetrou, Eirini P.
- Published
- 2024
- Full Text
- View/download PDF
48. Does increasing the retirement age increase youth unemployment? Evidence from an agent-based macro model: Does increasing the retirement age increase youth unemployment?...
- Author
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Chen, Siyan and Desiderio, Saul
- Published
- 2024
- Full Text
- View/download PDF
49. Comparison of two cultivation methods for domesticating wild red algal eucheumatoids for use in the seaweed industry
- Author
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Yahya, Nurulafifah, Poong, Sze-Wan, Brodie, Juliet, Cottier-Cook, Elizabeth J., Wilbraham, Joanna, Mallinson, Saul, Kassim, Azhar, Mansor, Ku Nor Afiza Asnida Ku, and Lim, Phaik-Eem
- Published
- 2024
- Full Text
- View/download PDF
50. How Police Officers Experience Suspect Interviews: Beliefs and Practices in the Belgian Interview Room
- Author
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Schell-Leugers, Jennifer Maria, Vanderhallen, Miet, Bogaard, Glynis, Maegherman, Enide, Jung, Lara Gil, Nieuwkamp, Veerle, and Kassin, Saul M.
- Published
- 2024
- Full Text
- View/download PDF
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