330,184 results on '"John, H. A."'
Search Results
2. Shadows and subsystems of generalized probabilistic theories: when tomographic incompleteness is not a loophole for contextuality proofs
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Schmid, David, Selby, John H., Rossi, Vinicius P., Baldijão, Roberto D., and Sainz, Ana Belén
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Quantum Physics - Abstract
It is commonly believed that failures of tomographic completeness undermine assessments of nonclassicality in noncontextuality experiments. In this work, we study how such failures can indeed lead to mistaken assessments of nonclassicality. We then show that proofs of the failure of noncontextuality are robust to a very broad class of failures of tomographic completeness, including the kinds of failures that are likely to occur in real experiments. We do so by showing that such proofs actually rely on a much weaker assumption that we term relative tomographic completeness: namely, that one's experimental procedures are tomographic for each other. Thus, the failure of noncontextuality can be established even with coarse-grained, effective, emergent, or virtual degrees of freedom. This also implies that the existence of a deeper theory of nature (beyond that being probed in one's experiment) does not in and of itself pose any challenge to proofs of nonclassicality. To prove these results, we first introduce a number of useful new concepts within the framework of generalized probabilistic theories (GPTs). Most notably, we introduce the notion of a GPT subsystem, generalizing a range of preexisting notions of subsystems (including those arising from tensor products, direct sums, decoherence processes, virtual encodings, and more). We also introduce the notion of a shadow of a GPT fragment, which captures the information lost when one's states and effects are unknowingly not tomographic for one another., Comment: 21 pages plus appendices; Many figures and diagrams
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- 2024
3. The Arpu Kuilpu Meteorite: In-depth characterization of an H5 chondrite delivered from a Jupiter Family Comet orbit
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Anderson, Seamus L., Benedix, Gretchen K., Godel, Belinda, Alosius, Romain M. L., Krietsch, Daniela, Busemann, Henner, Maden, Colin, Friedrich, Jon M., McMonigal, Lara R., Welten, Kees C., Caffee, Marc W., Macke, Robert J., Cadogan, Seán, Ryan, Dominic H., Jourdan, Fred, Mayers, Celia, Laubenstein, Matthias, Greenwood, Richard C., Roberts, Malcom P., Devillepoix, Hadrien A. R., Sansom, Eleanor K., Towner, Martin C., Cupák, Martin, Bland, Philip A., Forman, Lucy V., Fairweather, John H., Rogers, Ashley F., and Timms, Nicholas E.
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Astrophysics - Earth and Planetary Astrophysics ,Physics - Geophysics - Abstract
Over the Nullarbor Plain in South Australia, the Desert Fireball Network detected a fireball on the night of 1 June 2019 (7:30 pm local time), and six weeks later recovered a single meteorite (42 g) named Arpu Kuilpu. This meteorite was then distributed to a consortium of collaborating institutions to be measured and analyzed by a number of methodologies including: SEM-EDS, EPMA, ICP-MS, gamma-ray spectrometry, ideal gas pycnometry, magnetic susceptibility measurement, {\mu}CT, optical microscopy, and accelerator and noble gas mass spectrometry techniques. These analyses revealed that Arpu Kuilpu is an unbrecciated H5 ordinary chondrite, with minimal weathering (W0-1) and minimal shock (S2). The olivine and pyroxene mineral compositions (in mol%) are Fa: 19.2 +- 0.2, and Fs: 16.8 +- 0.2, further supporting the H5 type and class. The measured oxygen isotopes are also consistent with an H chondrite ({\delta}17O = 2.904 +- 0.177; {\delta}18O = 4.163 +- 0.336; {\Delta}17O = 0.740 +- 0.002). Ideal gas pycnometry measured bulk and grain densities of 3.66 +- 0.02 and 3.77 +- 0.02 g cm-3, respectively, yielding a porosity of 3.0 % +- 0.7. The magnetic susceptibility of this meteorite is log X = 5.16 +- 0.08. The most recent impact-related heating event experienced by Arpu Kuilpu was measured by 40Ar/39Ar chronology to be 4467 +- 16 Ma, while the cosmic ray exposure age is estimated to be between 6-8 Ma. The noble gas isotopes, radionuclides, and fireball observations all indicate that Arpu Kuilpu's meteoroid was quite small (maximum radius of 10 cm, though more likely between 1-5 cm). Although this meteorite is a rather ordinary ordinary chondrite, its prior orbit resembled that of a Jupiter Family Comet (JFC) further lending support to the assertion that many cm- to m-sized objects on JFC orbits are asteroidal rather than cometary in origin.
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- 2024
4. The K2 and TESS Synergy III: search and rescue of the lost ephemeris for K2's first planet
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Thygesen, Erica, Rodriguez, Joseph E., De Beurs, Zoë L., Vanderburg, Andrew, Livingston, John H., Irwin, Jonathon, Venner, Alexander, Cretignier, Michael, Collins, Karen A., Bieryla, Allyson, Charbonneau, David, Crossfield, Ian J. M., Dumusque, Xavier, Kielkopf, John, Latham, David W., and Werner, Michael
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Astrophysics - Earth and Planetary Astrophysics - Abstract
K2-2 b/HIP 116454 b, the first exoplanet discovery by K2 during its Two-Wheeled Concept Engineering Test, is a sub-Neptune (2.5 $\pm$ 0.1 $R_\oplus$, 9.7 $\pm$ 1.2 $M_\oplus$) orbiting a relatively bright (KS = 8.03) K-dwarf on a 9.1 day period. Unfortunately, due to a spurious follow-up transit detection and ephemeris degradation, the transit ephemeris for this planet was lost. In this work, we recover and refine the transit ephemeris for K2-2 b, showing a $\sim40{\sigma}$ discrepancy from the discovery results. To accurately measure the transit ephemeris and update the parameters of the system, we jointly fit space-based photometric observations from NASA's K2, TESS, and Spitzer missions with new photometric observations from the ground, as well as radial velocities from HARPS-N that are corrected for stellar activity using a new modeling technique. Ephemerides becoming lost or significantly degraded, as is the case for most transiting planets, highlights the importance of systematically updating transit ephemerides with upcoming large efforts expected to characterize hundreds of exoplanet atmospheres. K2-2 b sits at the high-mass peak of the known radius valley for sub-Neptunes, and is now well-suited for transmission spectroscopy with current and future facilities. Our updated transit ephemeris will ensure no more than a 13-minute uncertainty through 2030., Comment: Accepted for publication in AJ. 15 pages, 6 figures, 8 tables
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- 2024
5. Narrow Linewidth Distributed Feedback Lasers Utilizing Distributed Phase Shift
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Sun, Yiming, Yuan, Bocheng, Sun, Xiao, Zhu, Simeng, Fan, Yizhe, Al-Rubaiee, Mohanad, Marsh, John H., Sweeney, Stephen J., and Hou, Lianping
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Physics - Optics ,78 - Abstract
This study proposes and experimentally demonstrates a distributed feedback (DFB) laser with a distributed phase shift (DPS) region at the center of the DFB cavity. By modeling the field intensity distribution in the cavity and the output spectrum, the DPS region length and phase shift values have been optimized. Experimental comparisons with lasers using traditional {\pi}-phase shifts confirm that DFB lasers with optimized DPS lengths and larger phase shifts (up to 15{\pi}) achieve stable single longitudinal mode operation over a broader current range, with lower threshold current, higher power slope efficiency, and a higher side mode suppression ratio (SMSR). Furthermore, the minimum optical linewidth is reduced significantly, from 1.3 MHz to 220 kHz., Comment: 5 pages, 5 figures
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- 2024
6. Low abundances of TiO and VO on the Dayside of KELT-9 b: Insights from Ground-Based Photometric Observations
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Hayashi, Yuya, Narita, Norio, Fukui, Akihiko, Changeat, Quentin, Kawauchi, Kiyoe, Ikuta, Kai, Palle, Enric, Murgas, Felipe, Parviainen, Hannu, Esparza-Borges, Emma, Peláez-Torres, Alberto, Gallardo, Pedro Pablo Meni, Morello, Giuseppe, Fernández-Rodríguez, Gareb, García, Néstor Abreu, Torres, Sara Muñoz, Borrás, Yéssica Calatayud, Rodríguez, Pilar Montañés, Livingston, John H., Watanabe, Noriharu, de Leon, Jerome P., Kawai, Yugo, Isogai, Keisuke, and Mori, Mayuko
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Astrophysics - Earth and Planetary Astrophysics - Abstract
We present ground-based photometric observations of secondary eclipses of the hottest known planet KELT-9b using MuSCAT2 and Sinistro. We detect secondary eclipse signals in $i$ and $z_{\rm s}$ with eclipse depths of $373^{+74}_{-75}$ ppm and $638^{+199}_{-178}$, respectively. We perform an atmospheric retrieval on the emission spectrum combined with the data from HST/WFC3, Spitzer, TESS, and CHEOPS to obtain the temperature profile and chemical abundances, including TiO and VO, which have been thought to produce temperature inversion structures in the dayside of ultra-hot Jupiters. While we confirm a strong temperature inversion structure, we find low abundances of TiO and VO with mixing ratios of $\rm{log(TiO)}=-7.80^{+0.15}_{-0.30}$ and $\rm{log(VO)}=-9.60^{+0.64}_{-0.57}$, respectively. The low abundances of TiO and VO are consistent with theoretical predictions for such an ultra-hot atmosphere. In such low abundances, TiO and VO have little effect on the temperature structure of the atmosphere. The abundance of ${\rm e}^{-}$, which serves as a proxy for ${\rm H}^{-}$ ions in this study, is found to be high, with $\rm{log(e^-)}=-4.89\pm{0.06}$. These results indicate that the temperature inversion in KELT-9 b's dayside atmosphere is likely not caused by TiO/VO, but rather by the significant abundance of ${\rm H}^{-}$ ions. The best-fit model cannot fully explain the observed spectrum, and chemical species not included in the retrieval may introduce modeling biases. Future observations with broader wavelength coverage and higher spectral resolution are expected to provide more accurate diagnostics on the presence and abundances of TiO/VO. These advanced observations will overcome the limitations of current data from HST and photometric facilities, which are constrained by narrow wavelength coverage and instrumental systematics., Comment: 16 pages, 9 figures, 4 tables, Accepted for publication in PASJ
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- 2024
7. Toward Improving Synthetic Audio Spoofing Detection Robustness via Meta-Learning and Disentangled Training With Adversarial Examples
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Wang, Zhenyu and Hansen, John H. L.
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Computer Science - Sound ,Computer Science - Artificial Intelligence ,Electrical Engineering and Systems Science - Audio and Speech Processing - Abstract
Advances in automatic speaker verification (ASV) promote research into the formulation of spoofing detection systems for real-world applications. The performance of ASV systems can be degraded severely by multiple types of spoofing attacks, namely, synthetic speech (SS), voice conversion (VC), replay, twins and impersonation, especially in the case of unseen synthetic spoofing attacks. A reliable and robust spoofing detection system can act as a security gate to filter out spoofing attacks instead of having them reach the ASV system. A weighted additive angular margin loss is proposed to address the data imbalance issue, and different margins has been assigned to improve generalization to unseen spoofing attacks in this study. Meanwhile, we incorporate a meta-learning loss function to optimize differences between the embeddings of support versus query set in order to learn a spoofing-category-independent embedding space for utterances. Furthermore, we craft adversarial examples by adding imperceptible perturbations to spoofing speech as a data augmentation strategy, then we use an auxiliary batch normalization (BN) to guarantee that corresponding normalization statistics are performed exclusively on the adversarial examples. Additionally, A simple attention module is integrated into the residual block to refine the feature extraction process. Evaluation results on the Logical Access (LA) track of the ASVspoof 2019 corpus provides confirmation of our proposed approaches' effectiveness in terms of a pooled EER of 0.87%, and a min t-DCF of 0.0277. These advancements offer effective options to reduce the impact of spoofing attacks on voice recognition/authentication systems., Comment: IEEE ACCESS 2024
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- 2024
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8. NeuralCRNs: A Natural Implementation of Learning in Chemical Reaction Networks
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Nagipogu, Rajiv Teja and Reif, John H.
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Computer Science - Machine Learning ,Computer Science - Emerging Technologies - Abstract
The remarkable ability of single-celled organisms to sense and react to the dynamic changes in their environment is a testament to the adaptive capabilities of their internal biochemical circuitry. One of the goals of synthetic biology is to develop biochemical analogues of such systems to autonomously monitor and control biochemical processes. Such systems may have impactful applications in fields such as molecular diagnostics, smart therapeutics, and in vivo nanomedicine. So far, the attempts to create such systems have been focused on functionally replicating the behavior of traditional feedforward networks in abstract and DNA-based synthetic chemistries. However, the inherent incompatibility between digital and chemical modes of computation introduces several nonidealities into these implementations, making it challenging to realize them in practice. In this work, we present NeuralCRNs, a novel supervised learning framework constructed as a collection of deterministic chemical reaction networks (CRNs). Unlike prior works, the NeuralCRNs framework is founded on dynamical system-based learning implementations and, thus, results in chemically compatible computations. First, we show the construction and training of a supervised learning classifier for linear classification. We then extend this framework to support nonlinear classification. We then demonstrate the validity of our constructions by training and evaluating them first on several binary and multi-class classification datasets with complex class separation boundaries. Finally, we detail several considerations regarding the NeuralCRNs framework and elaborate on the pros and cons of our methodology compared to the existing works.
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- 2024
9. Deepest limits on scattered light emission from the Epsilon Eridani inner debris disk with HST/STIS
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M., Sai Krishanth P., Douglas, Ewan S., Anche, Ramya M., Hom, Justin, Cahoy, Kerri L., Debes, John H., Jang-Condell, Hannah, Rebollido, Isabel, Ren, Bin B., Stark, Christopher C., Thompson, Robert, and Xin, Yinzi
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Epsilon Eridani ($\epsilon$ Eri) is one of the first debris disk systems detected by the Infrared Astronomical Satellite (IRAS). However, the system has thus far eluded detection in scattered light with no components having been directly imaged. Its similarity to a relatively young Solar System combined with its proximity makes it an excellent candidate to further our understanding of planetary system evolution. We present a set of coronagraphic images taken using the Space Telescope Imaging Spectrograph (STIS) coronagraph on the Hubble space telescope at a small inner working angle to detect a predicted warm inner debris disk inside 1". We used three different post-processing approaches; Non-negative Matrix Factorization (NMF), Karhunen-Lo`eve Image Processing (KLIP), and Classical reference differential imaging (RDI), to best optimize reference star subtraction, and find that NMF performed the best overall while KLIP produced the absolute best contrast inside 1". We present limits on scattered light from warm dust, with constraints on surface brightness at 6 mJy/as$^2$ at our inner working angle of 0.6". We also place a constraint of 0.5 mJy/as$^2$ outside 1", which gives us an upper limit on the brightness for outer disks and substellar companions. Finally, we calculated an upper limit on the dust albedo at $\omega <$ 0.487., Comment: 13+2 pages, 7+2 figures; Accepted for publication in the Astronomical Journal
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- 2024
10. Twirled worlds: symmetry-induced failures of tomographic locality
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Centeno, Daniel, Erba, Marco, Schmid, David, Selby, John H., Spekkens, Robert W., Soltani, Sina, Surace, Jacopo, Wilce, Alex, and Yīng, Yìlè
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Quantum Physics - Abstract
Tomographic locality is a principle commonly used in the program of finding axioms that pick out quantum theory within the landscape of possible theories. The principle asserts the sufficiency of local measurements for achieving a tomographic characterization of any bipartite state. In this work, we explore the meaning of the principle of tomographic locality by developing a simple scheme for generating a wide variety of theories that violate the principle. In this scheme, one starts with a tomographically local theory -- which can be classical, quantum or post-quantum -- and a physical symmetry, and one restricts the processes in the theory to all and only those that are covariant with respect to that symmetry. We refer to the resulting theories as twirled worlds. We show that failures of tomographic locality are ubiquitous in twirled worlds. From the possibility of such failures in classical twirled worlds, we argue that the failure of tomographic locality (i.e., tomographic nonlocality) does not imply ontological holism. Our results also demonstrate the need for researchers seeking to axiomatize quantum theory to take a stand on the question of whether there are superselection rules that have a fundamental status., Comment: 5+12 pages, 2 figures. Comments welcome!
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- 2024
11. Navigating the United States Legislative Landscape on Voice Privacy: Existing Laws, Proposed Bills, Protection for Children, and Synthetic Data for AI
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Dutta, Satwik and Hansen, John H. L.
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Computer Science - Computers and Society ,Computer Science - Cryptography and Security ,Computer Science - Sound ,Electrical Engineering and Systems Science - Audio and Speech Processing ,I.2 ,J.1 - Abstract
Privacy is a hot topic for policymakers across the globe, including the United States. Evolving advances in AI and emerging concerns about the misuse of personal data have pushed policymakers to draft legislation on trustworthy AI and privacy protection for its citizens. This paper presents the state of the privacy legislation at the U.S. Congress and outlines how voice data is considered as part of the legislation definition. This paper also reviews additional privacy protection for children. This paper presents a holistic review of enacted and proposed privacy laws, and consideration for voice data, including guidelines for processing children's data, in those laws across the fifty U.S. states. As a groundbreaking alternative to actual human data, ethically generated synthetic data allows much flexibility to keep AI innovation in progress. Given the consideration of synthetic data in AI legislation by policymakers to be relatively new, as compared to that of privacy laws, this paper reviews regulatory considerations for synthetic data., Comment: 5 pages, 2 figures, accepted at the Interspeech SynData4GenAI 2024 workshop
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- 2024
12. First Comparative Exoplanetology Within a Transiting Multi-planet System: Comparing the atmospheres of V1298 Tau b and c
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Barat, Saugata, Désert, Jean-Michel, Goyal, Jayesh M., Vazan, Allona, Kawashima, Yui, Fortney, Jonathan J., Bean, Jacob L., Line, Michael R., Panwar, Vatsal, Jacobs, Bob, Shivkumar, Hinna, Sikora, James, Baeyens, Robin, Oklopcić, Antonija, David, Trevor J., and Livingston, John H.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
The V1298 Tau system (20-30Myr), is a benchmark young multi-planet system that provides the opportunity to perform comparative exoplanetology between planets orbiting the same star right after their formation. We present the first atmospheric comparison between two planets in the same transiting system: V1298 Tau b and V1298 Tau c. We derive constraints on the mass of planet b and c (<20M$_\oplus$ at 3$\sigma$ confidence level and $17_{-6}^{+13} M_{\oplus}$ respectively) and atmospheric metallicity (logZ/Z$_\odot$=-2.04$_{-0.59}^{0.69}$, -0.16$_{-0.94}^{1.15}$ respectively) from atmospheric retrievals. The V1298 Tau planets, are likely to be similar in terms of mass at the current age, implying that both planets are potential sub-Neptune/super-Earth progenitors. However, planet c is expected to lose a higher fraction of its mass compared to planet b given its close proximity to the host star. Alternatively, the observed spectrum of planet c can be explained by atmospheric hazes, which is in contrast to planet b where efficient haze formation can be ruled out. Higher haze formation efficiency in planet c could be due to differences in atmospheric composition, temperature and higher UV flux incident compared to planet b., Comment: Submitted to Astronomy ad Astrophysics
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- 2024
13. Noncontextuality inequalities for prepare-transform-measure scenarios
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Schmid, David, Baldijão, Roberto D., Selby, John H., Sainz, Ana Belén, and Spekkens, Robert W.
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Quantum Physics - Abstract
We provide the first systematic technique for deriving witnesses of contextuality in prepare-transform-measure scenarios. More specifically, we show how linear quantifier elimination can be used to compute a polytope of correlations consistent with generalized noncontextuality in such scenarios. This polytope is specified as a set of noncontextuality inequalities that are necessary and sufficient conditions for observed data in the scenario to admit of a classical explanation relative to any linear operational identities, if one ignores some constraints from diagram preservation. While including these latter constraints generally leads to tighter inequalities, it seems that nonlinear quantifier elimination would be required to systematically include them. We also provide a linear program which can certify the nonclassicality of a set of numerical data arising in a prepare-transform-measure experiment. We apply our results to get a robust noncontextuality inequality for transformations that can be violated within the stabilizer subtheory. Finally, we give a simple algorithm for computing all the linear operational identities holding among a given set of states, of transformations, or of measurements., Comment: 15 pages + appendices; 3 figures
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- 2024
14. Narrow Linewidth Laser Based on Extended Topological Interface States in One-Dimensional Photonic Crystals
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Sun, Xiao, Li, Zhibo, Sun, Yiming, Wang, Yupei, Wang, Jue, Cheng, Huihua, Fu, Cong, Marsh, John H., Kelly, Anthony E., and Hou, Lianping
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Physics - Optics - Abstract
Recent advances in topological one-dimensional photonic crystal concepts have enabled the development of robust light-emitting devices by incorporating a topological interface state (TIS) at the cavity center. In this study, we theoretically and experimentally demonstrate a one-dimensional TIS-extended photonic crystal (1D-TISE-PC) structure. By integrating a linearly dispersive zero-index one-dimensional photonic crystal structure with a four-phase shift sampled grating, photons propagate along the cavity without phase differences, enhancing the robustness to material variations and extending the TIS. Our findings indicate that extending the TIS promotes a more uniform photon distribution along the laser cavity and mitigates the spatial hole burning (SHB) effect. We fabricated and characterized a 1550 nm sidewall 1D-TISE-PC semiconductor laser, achieving stable single-mode operation across a wide current range from 60 to 420 mA, with a side-mode suppression ratio of 50 dB. The 1D-TISE-PC structure exhibited a linewidth narrowing effect to approximately 150 kHz Lorentzian linewidth. Utilizing reconstruction equivalent-chirp technology for the 4PS sampled grating enabled precise wavelength control in 1D-TISE-PC laser arrays, achieving a wavelength spacing of 0.796 nm +- 0.003 nm. We show that the TIS still exists in the TISE cavity and topological protection is preserved. Its mode extension characteristics mitigate the SHB so narrows the linewidth. We argue that the design simplicity and improvement of the fabrication tolerance make this architecture suitable for high-power and narrow-linewidth semiconductor lasers development.
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- 2024
15. TESS Investigation -- Demographics of Young Exoplanets (TI-DYE) II: a second giant planet in the 17-Myr system HIP 67522
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Barber, Madyson G., Thao, Pa Chia, Mann, Andrew W., Vanderburg, Andrew, Mori, Mayuko, Livingston, John H., Fukui, Akihiko, Narita, Norio, Kraus, Adam L., Tofflemire, Benjamin M., Newton, Elisabeth R., Winn, Joshua N., Jenkins, Jon M., Seager, Sara, Collins, Karen A., and Twicken, Joseph D.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
The youngest ($<$50 Myr) planets are vital to understand planet formation and early evolution. The 17 Myr system HIP 67522 is already known to host a giant ($\simeq$10$R_\oplus$) planet on a tight orbit. In the discovery paper, Rizzuto et al. 2020 reported a tentative single transit detection of an additional planet in the system using TESS. Here, we report the discovery of HIP 67522 c which matches with that single transit event. We confirm the signal with ground-based multi-wavelength photometry from Sinistro and MuSCAT4. At a period of 14.33 days, planet c is close to a 2:1 mean motion resonance with b (6.96 days or 2.06:1). The light curve shows distortions during many of the transits, which are consistent with spot crossing events and/or flares. Fewer stellar activity events are seen in the transits of planet b, suggesting that planet c is crossing a more active latitude. Such distortions, combined with systematics in the TESS light curve extraction, likely explain why planet c was previously missed., Comment: Accepted for publication in ApJ Letters
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- 2024
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16. We Need Variations in Speech Synthesis: Sub-center Modelling for Speaker Embeddings
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Ulgen, Ismail Rasim, Busso, Carlos, Hansen, John H. L., and Sisman, Berrak
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Electrical Engineering and Systems Science - Audio and Speech Processing ,Computer Science - Machine Learning - Abstract
In speech synthesis, modeling of rich emotions and prosodic variations present in human voice are crucial to synthesize natural speech. Although speaker embeddings have been widely used in personalized speech synthesis as conditioning inputs, they are designed to lose variation to optimize speaker recognition accuracy. Thus, they are suboptimal for speech synthesis in terms of modeling the rich variations at the output speech distribution. In this work, we propose a novel speaker embedding network which utilizes multiple class centers in the speaker classification training rather than a single class center as traditional embeddings. The proposed approach introduces variations in the speaker embedding while retaining the speaker recognition performance since model does not have to map all of the utterances of a speaker into a single class center. We apply our proposed embedding in voice conversion task and show that our method provides better naturalness and prosody in synthesized speech., Comment: Submitted to IEEE Signal Processing Letters
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- 2024
17. A Low-Cost Small-Mammal Camera Trap for Research and Education
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Porter, John H. and Dueser, Raymond D.
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- 2024
18. Temporal progression of tau pathology and neuroinflammation in a rhesus monkey model of Alzheimer's disease
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Beckman, Danielle, Diniz, Giovanne B, Ott, Sean, Hobson, Brad, Chaudhari, Abhijit J, Muller, Scott, Chu, Yaping, Takano, Akihiro, Schwarz, Adam J, Yeh, Chien‐Lin, McQuade, Paul, Chakrabarty, Paramita, Kanaan, Nicholas M, Quinton, Maria S, Simen, Arthur A, Kordower, Jeffrey H, and Morrison, John H
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Biomedical and Clinical Sciences ,Neurosciences ,Clinical Sciences ,Alzheimer's Disease ,Brain Disorders ,Dementia ,Alzheimer's Disease including Alzheimer's Disease Related Dementias (AD/ADRD) ,Biomedical Imaging ,Aging ,Neurodegenerative ,Acquired Cognitive Impairment ,2.1 Biological and endogenous factors ,4.2 Evaluation of markers and technologies ,Neurological ,Animals ,Macaca mulatta ,Alzheimer Disease ,Disease Models ,Animal ,tau Proteins ,Disease Progression ,Positron-Emission Tomography ,Magnetic Resonance Imaging ,Neuroinflammatory Diseases ,Entorhinal Cortex ,Biomarkers ,Mutation ,Brain ,Male ,Alzheimer's disease ,biomarkers ,glial cells ,nonhuman primates ,tau ,Geriatrics ,Clinical sciences ,Biological psychology - Abstract
IntroductionThe understanding of the pathological events in Alzheimer's disease (AD) has advanced dramatically, but the successful translation from rodent models into efficient human therapies is still problematic.MethodsTo examine how tau pathology can develop in the primate brain, we injected 12 macaques with a dual tau mutation (P301L/S320F) into the entorhinal cortex (ERC). An investigation was performed using high-resolution microscopy, magnetic resonance imaging (MRI), positron emission tomography (PET), and fluid biomarkers to determine the temporal progression of the pathology 3 and 6 months after the injection.ResultsUsing quantitative microscopy targeting markers for neurodegeneration and neuroinflammation, as well as fluid and imaging biomarkers, we detailed the progression of misfolded tau spreading and the consequential inflammatory response induced by glial cells.DiscussionBy combining the analysis of several in vivo biomarkers with extensive brain microscopy analysis, we described the initial steps of misfolded tau spreading and neuroinflammation in a monkey model highly translatable to AD patients.HighlightsDual tau mutation delivery in the entorhinal cortex induces progressive tau pathology in rhesus macaques. Exogenous human 4R-tau coaptates monkey 3R-tau during transneuronal spread, in a prion-like manner. Neuroinflammatory response is coordinated by microglia and astrocytes in response to tau pathology, with microglia targeting early tau pathology, while astrocytes engaged later in the progression, coincident with neuronal death. Monthly collection of CSF and plasma revealed a profile of changes in several AD core biomarkers, reflective of neurodegeneration and neuroinflammation as early as 1 month after injection.
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- 2024
19. Isotopes in the Studies of Total Red-Cell Volume, of Rate and Site of Red-Cell Production and Destruction, and of Red-Cell Life Span
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Berlin, N I and Lawrence, John H
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- 2024
20. Point-of-Care Ultrasound for Earlier Detection of Pediatric Pneumonia
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Priester, John H., Kumar, Prasanna, Naumann, Jesse, Dolbec, Katherine, Weimersheimer, Peter, and Pulcini, Christian D.
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point-of-care ultrasound ,pneumonia ,Lung ultrasound ,Chest x-ray ,pediatrics - Abstract
Case Presentation: An 8-month-old infant presented to a general emergency department with chief complaints of rhinorrhea, decreased activity, and fever. A point-of-care lung ultrasound (LUS) was performed at bedside with potential early findings of pneumonia. Based on these findings on LUS, a chest radiograph (CXR) was ordered and performed with no acute findings. He was discharged without antibiotics based on these findings; unfortunately, he returned two days later with worsening symptoms requiring chest tube placement, mechanical ventilation, and prolonged hospitalization for complicated bacterial pneumonia.Discussion: Pneumonia is a major cause of pediatric morbidity and mortality worldwide. Despite evidence supporting the utilization of LUS for the diagnosis of pediatric pneumonia, CXR remains the default imaging for clinical decision-making in most settings. In this case, earlier antibiotics and higher reliance on LUS for clinical decision-making may have prevented the morbidity associated with this hospitalization.
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- 2024
21. Translational Bioethical Decision‐Making: Human Brain Organoids as a Case Study
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Evans, John H
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Philosophy and Religious Studies ,History and Philosophy Of Specific Fields ,Neurosciences ,Biotechnology ,Humans ,Organoids ,Brain ,Translational Research ,Biomedical ,Decision Making ,Bioethics ,Social Values ,human brain organoids ,public understanding of science ,public values ,translational bioethics - Abstract
In an earlier essay, I advocated that translational bioethics uses the public's values, determined through social science, in its analysis of translational science technologies. It may be unclear what those values might be, and whether such a translational ethics would necessarily conclude that cutting edge technologies should not be developed. In this essay, I show the public's values relevant to human brain organoids and argue that a translational bioethics analysis using these values would support continued organoid research.
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- 2024
22. OH mid-infrared emission as a diagnostic of H$_2$O UV photodissociation. III. Application to planet-forming disks
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Tabone, Benoît, van Dishoeck, Ewine F., and Black, John H.
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
JWST gives a unique access to the physical and chemical structure of inner disks ($<10$~au), where the majority of the planets are forming. However, the interpretation of mid-infrared (mid-IR) spectra requires detailed thermo-chemical models able to provide synthetic spectra readily comparable to spectroscopic observations. Our goal is to explore the potential of mid-IR emission of OH to probe H$_2$O photodissociation. We include in the DALI disk model prompt emission of OH following photodissociation of H$_2$O in its $\tilde{B}$ electronic state ($\lambda < 144$~nm). This model allows to compute in a self-consistent manner the thermo-chemical structure of the disk and the resulting mid-IR line intensities of OH and H$_2$O. The OH line intensities in the $9-13~\mu$m range are proportional to the total amount of water photodissociated. As such, these lines are a tracer of the amount of water exposed to the FUV field, which depends on the temperature, density, and strength of the FUV field reaching the upper molecular layers. In particular, the OH line fluxes primarily scale with the FUV field emitted by the star in contrast with H$_2$O lines in the 10-20$~\mu$m range which scale with the bolometric luminosity. OH is therefore a key diagnostic to probe the effect of Ly$\alpha$ and constrain the dust FUV opacity in the upper molecular layers. A strong asymmetry between the A' and A'' components of each rotational quadruplet is also predicted. OH mid-IR emission is a powerful tool to probe H$_2$O photodissociation and infer the physical conditions in disk atmospheres. As such, the inclusion of OH mid-IR lines in the analysis of JWST-MIRI spectra will be key for robustly inferring the composition of planet-forming disks. The interpretation of less excited OH lines requires additional quantum calculations of the formation pumping of OH levels by O+H$_2$ and the collisional rate coefficients., Comment: Accepted for publication in Astronomy & Astrophysics
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- 2024
23. Fast Small-Angle X-ray Scattering Tensor Tomography: An Outlook into Future Applications in Life Sciences
- Author
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Appel, Christian, Schmeltz, Margaux, Rodriguez-Fernandez, Irene, Anschuetz, Lukas, Nielsen, Leonard C., Panepucci, Ezequiel, Marijolovic, Tomislav, Wakonig, Klaus, Ivanovic, Aleksandra, Bonnin, Anne, Leonarski, Filip, Wojdyla, Justyna, Tomizaki, Takashi, Guizar-Sicairos, Manuel, Smith, Kate, Beale, John H., Glettig, Wayne, McAuley, Katherine, Bunk, Oliver, Wang, Meitian, and Liebi, Marianne
- Subjects
Physics - Medical Physics ,Condensed Matter - Materials Science - Abstract
Small Angle-X-ray Scattering Tensor Tomography (SAS-TT) is a relatively new, but powerful technique for studying the multiscale architecture of hierarchical structures, which is of particular interest for life science applications. Currently, the technique is very demanding on synchrotron beamtime, which limits its applications, especially for cases requiring a statistically relevant amount of sample. This study reports the first SAS-TT measurement at a macromolecular X-ray crystallography beamline, PX-I at the SLS, with an improvement in data acquisition time from 96 h/Mvoxel in the pilot experiments to 6 h/Mvoxel, defining a new standard for fast SAS-TT and allowing the measurement of a full tomogram in 1.2 hours. Measurements were performed on the long and lenticular process of the incus bone, one of the three human auditory ossicles. The main orientation and degree of alignment of the mineralised collagen fibrils are characterised, as well as the size and shape of the mineral particles which show relevant variations in different tissue locations. The study reveals three distinct regions of high fibril alignment, most likely important pathways of sound throughout the ossicular chain, and highlights the potential of the technique to aid in future developments in middle ear reconstructive surgery.
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- 2024
24. Robustness of contextuality under different types of noise as quantifiers for parity-oblivious multiplexing tasks
- Author
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Fonseca, Amanda M., Rossi, Vinicius P., Baldijão, Roberto D., Selby, John H., and Sainz, Ana Belén
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Quantum Physics - Abstract
Generalised contextuality is a well-motivated notion of nonclassicality powering up a myriad of quantum tasks, among which is the celebrated case of a two-party information processing task where classical information is compressed in a quantum channel, the parity-oblivious multiplexing (POM) task. The success rate is the standard quantifier of resourcefulness for this task, while robustness-based quantifiers are as operationally motivated and have known general properties. In this work, we leverage analytical and numerical tools to estimate robustness of contextuality in POM scenarios under different types of noise. We conclude that for the 3-to-1 case the robustness of contextuality to depolarisation, as well as a minimisation of the robustness of contextuality to dephasing over all bases, are good quantifiers for the nonclassical advantage of this scenario. Moreover, we obtain a general relation between robustness of contextuality to depolarisation and the success rate in any $n$-to-1 POM scenario and show how it can be used to bound the number of bits encoded in this task., Comment: 11 pages, 7 figures. Comments are welcome
- Published
- 2024
25. Low-probability of Intercept/Detect (LPI/LPD) Secure Communications Using Antenna Arrays Employing Rapid Sidelobe Time Modulation
- Author
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Zhao, Jiahao, Qiao, Shichen, Booske, John H., and Behdad, Nader
- Subjects
Electrical Engineering and Systems Science - Systems and Control ,Electrical Engineering and Systems Science - Signal Processing - Abstract
We present an electronically-reconfigurable antenna array offering low probability of intercept/detect (LPI/LPD) and secure communications capabilities simultaneously at the physical layer. This antenna array is designed to provide rapidly time-varying sidelobes and a stationary main lobe. By performing rapid sidelobe time modulation (SLTM), the signal transmitted in the undesired directions (i.e., through sidelobes) undergoes spread-spectrum distortion making it more difficult to be detected, intercepted, and deciphered while the signal transmitted in the desired direction (i.e., through the main lobe) is unaffected. Therefore, the intended receiver would not need additional modifications (i.e. encryption keys) to detect and recover the signal. We describe the operating principles of this SLTM array and validate its spread-spectrum SLTM sequence generation in undesired directions through theory, simulations, and experiments. Using a fabricated SLTM prototype operating at X band, we conducted system-level measurements to demonstrate its LPI/LPD, secure communications, and jamming resilience capabilities. The presented method is a physical layer technique, which can bring LPI/LPD capabilities to existing communications systems by simply replacing their antennas with SLTM arrays. This technique can be used independently or in combination with additional coding and signal-processing techniques to achieve further enhancements in LPI/LPD and secure communications., Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible
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- 2024
26. Why does the Milky Way have a metallicity floor?
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Smith, Britton D., O'Shea, Brian W., Khochfar, Sadegh, Turk, Matthew J., Wise, John H., and Norman, Michael L.
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
The prevalence of light element enhancement in the most metal-poor stars is potentially an indication that the Milky Way has a metallicity floor for star formation around $\sim$10$^{-3.5}$ Z$_{\odot}$. We propose that this metallicity floor has its origins in metal-enriched star formation in the minihalos present during the Galaxy's initial formation. To arrive at this conclusion, we analyze a cosmological radiation hydrodynamics simulation that follows the concurrent evolution of multiple Population III star-forming minihalos. The main driver for the central gas within minihalos is the steady increase in hydrostatic pressure as the halos grow. We incorporate this insight into a hybrid one-zone model that switches between pressure-confined and modified free-fall modes to evolve the gas density with time according to the ratio of the free-fall and sound-crossing timescales. This model is able to accurately reproduce the density and chemo-thermal evolution of the gas in each of the simulated minihalos up to the point of runaway collapse. We then use this model to investigate how the gas responds to the absence of H$_{2}$. Without metals, the central gas becomes increasingly stable against collapse as it grows to the atomic cooling limit. When metals are present in the halo at a level of $\sim$10$^{-3.7}$ Z$_{\odot}$, however, the gas is able to achieve gravitational instability while still in the minihalo regime. Thus, we conclude that the Galaxy's metallicity floor is set by the balance within minihalos of gas-phase metal cooling and the radiation background associated with its early formation environment., Comment: 11 pages, 5 figures, accepted for publication in MNRAS
- Published
- 2024
27. CO in the Draco Nebula: The Atomic-Molecular Transition
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Bieging, John H. and Kong, Shuo
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
This paper presents maps of the J=2-1 transition of CO toward the Draco Nebula Intermediate Velocity Cloud (IVC). The maps cover 8500 square arcmin with a velocity resolution of 0.33 km~s$^{-1}$ and angular resolution of 38", or 0.11 pc at the cloud distance of 600 pc. The mapped area includes all the emission detected by the {\it Herschel} satellite with 250 $\mu$m intensity >5 MJy/sr. Previously published observations of the far-IR emission and the 21 cm line of HI are used to derive the column density distribution of H$_2$ and the abundance ratio CO/H$_2$, as well as the distribution of the molecular fraction of hydrogen, which approaches 90\% over much of the brighter parts of the nebula. The CO emission is highly clumpy and closely resembles the structures seen in far-IR images. The kinematics of the CO show supersonic motions between clumps but near-thermal to trans-sonic motions within clumps, consistent with model predictions that the scale length for dissipation of supersonic turbulence should be $\sim0.1$ pc, mediated by kinematic viscosity and/or ambipolar diffusion. Different parts of the nebula show evidence for a spread of molecular formation timescales of a few 10$^5$ years, comparable to the dynamical timescale of the infalling gas. The IVC will likely merge with the Galactic interstellar medium in $\sim 10^7$ years, and the densest clumps may form an unbound cluster of low-mass stars., Comment: accepted by MNRAS
- Published
- 2024
28. Detection of an Earth-sized exoplanet orbiting the nearby ultracool dwarf star SPECULOOS-3
- Author
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Gillon, Michaël, Pedersen, Peter P., Rackham, Benjamin V., Dransfield, Georgina, Ducrot, Elsa, Barkaoui, Khalid, Burdanov, Artem Y., Schroffenegger, Urs, Chew, Yilen Gómez Maqueo, Lederer, Susan M., Alonso, Roi, Burgasser, Adam J., Howell, Steve B., Narita, Norio, de Wit, Julien, Demory, Brice-Olivier, Queloz, Didier, Triaud, Amaury H. M. J., Delrez, Laetitia, Jehin, Emmanuël, Hooton, Matthew J., Garcia, Lionel J., Muñoz, Clàudia Jano, Murray, Catriona A., Pozuelos, Francisco J., Sebastian, Daniel, Timmermans, Mathilde, Thompson, Samantha J., Aceituno, Jesús, Aganze, Christian, Amado, Pedro J., Baycroft, Thomas, Benkhaldoun, Zouhair, Berardo, David, Bolmont, Emeline, Clark, Catherine A., Davis, Yasmin T., Davoudi, Fatemeh, de Beurs, Zoë L., de Leon, Jerome P., Ikoma, Masahiro, Ikuta, Kai, Isogai, Keisuke, Fukuda, Izuru, Fukui, Akihiko, Gerasimov, Roman, Ghachoui, Mourad, Günther, Maximilian N., Hasler, Samantha, Hayashi, Yuya, Heng, Kevin, Hu, Renyu, Kagetani, Taiki, Kawai, Yugo, Kawauchi, Kiyoe, Kitzmann, Daniel, Koll, Daniel D. B., Lendl, Monika, Livingston, John H., Lyu, Xintong, Valdés, Erik A. Meier, Mori, Mayuko, McCormac, James J., Murgas, Felipe, Niraula, Prajwal, Pallé, Enric, Plauchu-Frayn, Ilse, Rebolo, Rafael, Sabin, Laurence, Schackey, Yannick, Schanche, Nicole, Selsis, Franck, Sota, Alfredo, Stalport, Manu, Standing, Matthew R., Stassun, Keivan G., Tamura, Motohide, Theissen, Christopher A., Turbet, Martin, Van Grootel, Valérie, Varas, Roberto, Watanabe, Noriharu, and Lang, Francis Zong
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
Located at the bottom of the main sequence, ultracool dwarf stars are widespread in the solar neighbourhood. Nevertheless, their extremely low luminosity has left their planetary population largely unexplored, and only one of them, TRAPPIST-1, has so far been found to host a transiting planetary system. In this context, we present the SPECULOOS project's detection of an Earth-sized planet in a 17 h orbit around an ultracool dwarf of M6.5 spectral type located 16.8 pc away. The planet's high irradiation (16 times that of Earth) combined with the infrared luminosity and Jupiter-like size of its host star make it one of the most promising rocky exoplanet targets for detailed emission spectroscopy characterization with JWST. Indeed, our sensitivity study shows that just ten secondary eclipse observations with the Mid-InfraRed Instrument/Low-Resolution Spectrometer on board JWST should provide strong constraints on its atmospheric composition and/or surface mineralogy.
- Published
- 2024
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29. The TESS-Keck Survey XX: 15 New TESS Planets and a Uniform RV Analysis of all Survey Targets
- Author
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Polanski, Alex S., Lubin, Jack, beard, Corey, Murphy, Jospeh M. Akana, Rubenzahl, Ryan, Hill, Michelle L., Crossfield, Ian J. M., Chontos, Ashley, Robertson, Paul, Isaacson, Howard, Kane, Stephen R., Ciardi, David R., Batalha, Natalie M., Dressing, Courtney, Fulton, Benjamin, Howard, Andrew W., Huber, Daniel, Petigura, Erik A., Weiss, Lauren M., Angelo, Isabel, Behmard, Aida, Blunt, Sarah, Brinkman, Casey L., Dai, Fei, Dalba, Paul A., Fetherolf, Tara, Giacalone, Steven, Hirsch, Lea A., Holcomb, Rae, Kosiarek, Molly R., Mayo, Andrew W., MacDougall, Mason G., Močnik, Teo, Pidhorodetska, Daria, Rice, Malena, Rosenthal, Lee J., Scarsdale, Nicholas, Turtelboom, Emma V., Tyler, Dakotah, Van Zandt, Judah, Yee, Samuel W., Coria, David R., Dulz, Shannon D., Hartman, Joel D., Householder, Aaron, Lange, Sarah, Langford, Andrew, Louden, Emma M., Gilbert, Emily A., Gonzales, Erica J., Schlieder, Joshua E., Boyle, Andrew W., Christiansen, Jessie L., Clark, Catherine A., Fernandes, Rachel B., Lund, Michael B., Savel, Arjun B., Gill, Holden, Beichman, Charles, Matson, Rachel, Matthews, Elisabeth C., Furlan, E., Howell, Steve B., Scott, Nicholas J., Everett, Mark E., Livingston, John H., Ershova, Irina O., Cheryasov, Dmitry V., Safonov, Boris, Lillo-Box, Jorge, Barrado, David, and Morales-Calderón, María
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
The Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new worlds, with TESS planet candidates now outnumbering the total number of confirmed planets from $\textit{Kepler}$. Owing to differences in survey design, TESS continues to provide planets that are better suited for subsequent follow-up studies, including mass measurement through radial velocity (RV) observations, compared to Kepler targets. In this work, we present the TESS-Keck Survey's (TKS) Mass Catalog: a uniform analysis of all TKS RV survey data which has resulted in mass constraints for 126 planets and candidate signals. This includes 58 mass measurements that have reached $\geq5\sigma$ precision. We confirm or validate 32 new planets from the TESS mission either by significant mass measurement (15) or statistical validation (17), and we find no evidence of likely false positives among our entire sample. This work also serves as a data release for all previously unpublished TKS survey data, including 9,204 RV measurements and associated activity indicators over our three year survey. We took the opportunity to assess the performance of our survey, and found that we achieved many of our goals including measuring the mass of 38 small ($<4R_{\oplus}$) planets, nearly achieving the TESS mission's basic science requirement. In addition, we evaluated the performance of the Automated Planet Finder (APF) as survey support and observed meaningful constraints on system parameters due to its more uniform phase coverage. Finally, we compared our measured masses to those predicted by commonly used mass-radius relations and investigated evidence of systematic bias., Comment: 51 pages (22 of text), 24 figures
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- 2024
- Full Text
- View/download PDF
30. On equivalence of gauge-invariant models for massive integer-spin fields
- Author
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Fegebank, John H. and Kuzenko, Sergei M.
- Subjects
High Energy Physics - Theory ,Mathematical Physics - Abstract
There are several approaches to formulate gauge-invariant models for massive integer-spin field in $d$ dimensions including the following: (i) in terms of symmetric tensor fields $\phi_{\mu_1 \dots \mu_k} $, with $k = s, s-1, \dots , 0$, restricted to be double traceless for $k\geq 4$; and (ii) in terms of a quartet of $traceful$ symmetric tensor fields $\psi_{\mu_1 \dots \mu_k} $, of rank $k=s,s-1,s-2, s-3$. We demonstrate that these formulations in Minkowski space ${\mathbb M}^d$ are equivalent to the gauge-invariant theory for a massive integer-spin field proposed in 1989 by Pashnev. We also make use of the Klishevich-Zinoviev theory in ${\mathbb M}^d$ to derive a generalisation of the Singh-Hagen model for a massive integer-spin field in $d>4 $ dimensions., Comment: 39 pages. This work includes the main results of the unpublished manuscript arXiv:2310.00951; V2: references and comments added
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- 2024
31. Kirkwood-Dirac representations beyond quantum states (and their relation to noncontextuality)
- Author
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Schmid, David, Baldijão, Roberto D., Yīng, Yìlè, Wagner, Rafael, and Selby, John H.
- Subjects
Quantum Physics - Abstract
Kirkwood-Dirac representations of quantum states are increasingly finding use in many areas within quantum theory. Usually, representations of this sort are only applied to provide a representation of quantum states (as complex functions over some set). We show how standard Kirkwood-Dirac representations can be extended to a fully compositional representation of all of quantum theory (including channels, measurements and so on), and prove that this extension satisfies the essential features of functoriality (namely, that the representation commutes with composition of channels), linearity, and quasistochasticity. Interestingly, the representation of a POVM element is uniquely picked out to be the collection of weak values for it relative to the bases defining the representation. We then prove that if one can find any Kirkwood-Dirac representation that is everywhere real and nonnegative for a given experimental scenario or fragment of quantum theory, then the scenario or fragment is consistent with the principle of generalized noncontextuality, a key notion of classicality in quantum foundations. We also show that the converse does not hold: even if one verifies that all Kirkwood-Dirac representations (as defined herein) of an experiment require negativity or imaginarity, one cannot generally conclude that the experiment witnesses contextuality., Comment: 5 pages; comments welcome!
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- 2024
32. Optimal Feeding of Swimming and Attached Ciliates
- Author
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Liu, Jingyi, Man, Yi, Costello, John H., and Kanso, Eva
- Subjects
Physics - Fluid Dynamics - Abstract
Ciliated microorganisms near the base of the aquatic food chain either swim to encounter prey or attach at a substrate and generate feeding currents to capture passing particles. Here, we represent attached and swimming ciliates using a popular spherical model in viscous fluid with slip surface velocity that afford analytical expressions of ciliary flows. We solve an advection-diffusion equation for the concentration of dissolved nutrients, where the P'eclet number (Pe) reflects the ratio of diffusive to advective time scales. For a fixed hydrodynamic power expenditure, we ask what ciliary surface velocities maximize nutrient flux at the microorganism's surface. We find that surface motions that optimize feeding depend on Pe. For freely swimming microorganisms at finite Pe, it is optimal to swim by employing a "treadmill" surface motion, but in the limit of large Pe, there is no difference between this treadmill solution and a symmetric dipolar surface velocity that keeps the organism stationary. For attached microorganisms, the treadmill solution is optimal for feeding at Pe below a critical value, but at larger Pe values, the dipolar surface motion is optimal. We verified these results in open-loop numerical simulations, asymptotic analysis, and using an adjoint-based optimization method. Our findings challenge existing claims that optimal feeding is optimal swimming across all P'eclet numbers, and provide new insights into the prevalence of both attached and swimming solutions in oceanic microorganisms., Comment: 36 pages, 4 figures
- Published
- 2024
33. PDRs4All IX. Sulfur elemental abundance in the Orion Bar
- Author
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Fuente, Asunción, Roueff, Evelyne, Petit, Franck Le, Bourlot, Jacques Le, Bron, Emeric, Wolfire, Mark G., Babb, James F., Yan, Pei-Gen, Onaka, Takashi, Black, John H., Schroetter, Ilane, Van De Putte, Dries, Sidhu, Ameek, Canin, Amélie, Trahin, Boris, Alarcón, Felipe, Chown, Ryan, Kannavou, Olga, Berné, Olivier, Habart, Emilie, Peeters, Els, Goicoechea, Javier R., Zannese, Marion, Meshaka, Raphael, Okada, Yoko, Röllig, Markus, Gal, Romane Le, Sales, Dinalva A., Palumbo, Maria Elisabetta, Baratta, Giuseppe Antonio, Madden, Suzanne C., Neelamkodan, Naslim, Zhang, Ziwei E., and Stancil, P. C.
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
One of the main problems in astrochemistry is determining the amount of sulfur in volatiles and refractories in the interstellar medium. The detection of the main sulfur reservoirs (icy H$_2$S and atomic gas) has been challenging, and estimates are based on the reliability of models to account for the abundances of species containing less than 1% of the total sulfur. The high sensitivity of the James Webb Space Telescope provides an unprecedented opportunity to estimate the sulfur abundance through the observation of the [S I] 25.249 $\mu$m line. We used the [S III] 18.7 $\mu$m, [S IV] 10.5 $\mu$m, and [S l] 25.249 $\mu$m lines to estimate the amount of sulfur in the ionized and molecular gas along the Orion Bar. For the theoretical part, we used an upgraded version of the Meudon photodissociation region (PDR) code to model the observations. New inelastic collision rates of neutral atomic sulfur with ortho- and para- molecular hydrogen were calculated to predict the line intensities. The [S III] 18.7 $\mu$m and [S IV] 10.5 $\mu$m lines are detected over the imaged region with a shallow increase (by a factor of 4) toward the HII region. We estimate a moderate sulfur depletion, by a factor of $\sim$2, in the ionized gas. The corrugated interface between the molecular and atomic phases gives rise to several edge-on dissociation fronts we refer to as DF1, DF2, and DF3. The [S l] 25.249 $\mu$m line is only detected toward DF2 and DF3, the dissociation fronts located farthest from the HII region. The detailed modeling of DF3 using the Meudon PDR code shows that the emission of the [S l] 25.249 $\mu$m line is coming from warm ($>$ 40 K) molecular gas located at A$_{\rm V}$ $\sim$ 1$-$5 mag from the ionization front. Moreover, the intensity of the [S l] 25.249 $\mu$m line is only accounted for if we assume the presence of undepleted sulfur., Comment: 16 pages, 6 figures. Accepted for publication in Astronomy and Astrophysics
- Published
- 2024
34. Class-E, Active Electrically-Small Antenna for High-Power Wideband Transmission at the High-Frequency (HF) Band
- Author
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Strachen, Nathan, Booske, John H., and Behdad, Nader
- Subjects
Physics - Applied Physics ,Electrical Engineering and Systems Science - Signal Processing ,Electrical Engineering and Systems Science - Systems and Control ,Physics - Instrumentation and Detectors - Abstract
Antennas operating at the high-frequency (HF) band (3-30 MHz) are frequently electrically small due to the large wavelength of electromagnetic waves (10-100 m). However, the bandwidth-efficiency products of passively matched electrically small antennas (ESAs) are fundamentally limited. Wideband HF waveforms using bandwidths of 24 kHz or more have recently received significant attention in military communications applications. Efficiently radiating such signals from conventional passive ESAs is very challenging due to fundamental physical limits on bandwidth-efficiency products of ESAs. However, active antennas are not subject to the same constraints. In this work, we present the design and experimental characterization of a high-power, active ESA with enhanced bandwidth-efficiency product compared to {that of} passively matched ESAs. Specifically, the proposed active ESA can radiate wideband HF signals with banwidths of 24 kHz or more, with total efficiencies up to 80$\%$, and radiated power levels approaching 100 W. Our approach uses a highly-efficient, integrated class-E switching circuit specifically designed to drive an electrically small, high-Q HF antenna over a bandwidth exceeding 24 kHz. Using a high-Q RLC antenna model, we have successfully demonstrated wideband binary ASK, PSK, and FSK modulations with the proposed class-E switching architecture. Experimental results indicate that the bandwidth-efficiency product of this class-E active antenna is 5.4-9.8 dB higher than that of an equivalent passive design with the same data rate, and bit-error-rate (BER)., Comment: 16 pages
- Published
- 2024
35. PDRs4All VIII: Mid-IR emission line inventory of the Orion Bar
- Author
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Van De Putte, Dries, Meshaka, Raphael, Trahin, Boris, Habart, Emilie, Peeters, Els, Berné, Olivier, Alarcón, Felipe, Canin, Amélie, Chown, Ryan, Schroetter, Ilane, Sidhu, Ameek, Boersma, Christiaan, Bron, Emeric, Dartois, Emmanuel, Goicoechea, Javier R., Gordon, Karl D., Onaka, Takashi, Tielens, Alexander G. G. M., Verstraete, Laurent, Wolfire, Mark G., Abergel, Alain, Bergin, Edwin A., Bernard-Salas, Jeronimo, Cami, Jan, Cuadrado, Sara, Dicken, Daniel, Elyajouri, Meriem, Fuente, Asunción, Joblin, Christine, Khan, Baria, Lacinbala, Ozan, Languignon, David, Gal, Romane Le, Maragkoudakis, Alexandros, Okada, Yoko, Pasquini, Sofia, Pound, Marc W., Robberto, Massimo, Röllig, Markus, Schefter, Bethany, Schirmer, Thiébaut, Tabone, Benoit, Vicente, Sílvia, Zannese, Marion, Colgan, Sean W. J., He, Jinhua, Rouillé, Gaël, Togi, Aditya, Aleman, Isabel, Auchettl, Rebecca, Baratta, Giuseppe Antonio, Bejaoui, Salma, Bera, Partha P., Black, John H., Boulanger, Francois, Bouwman, Jordy, Brandl, Bernhard, Brechignac, Philippe, Brünken, Sandra, Buragohain, Mridusmita, Burkhardt, Andrew, Candian, Alessandra, Cazaux, Stéphanie, Cernicharo, Jose, Chabot, Marin, Chakraborty, Shubhadip, Champion, Jason, Cooke, Ilsa R., Coutens, Audrey, Cox, Nick L. J., Demyk, Karine, Meyer, Jennifer Donovan, Foschino, Sacha, García-Lario, Pedro, Gerin, Maryvonne, Gottlieb, Carl A., Guillard, Pierre, Gusdorf, Antoine, Hartigan, Patrick, Herbst, Eric, Hornekaer, Liv, Issa, Lina, Jäger, Cornelia, Janot-Pacheco, Eduardo, Kannavou, Olga, Kaufman, Michael, Kemper, Francisca, Kendrew, Sarah, Kirsanova, Maria S., Klaassen, Pamela, Kwok, Sun, Labiano, Álvaro, Lai, Thomas S. -Y., Floch, Bertrand Le, Petit, Franck Le, Li, Aigen, Linz, Hendrik, Mackie, Cameron J., Madden, Suzanne C., Mascetti, Joëlle, McGuire, Brett A., Merino, Pablo, Micelotta, Elisabetta R., Morse, Jon A., Mulas, Giacomo, Neelamkodan, Naslim, Ohsawa, Ryou, Omont, Alain, Paladini, Roberta, Palumbo, Maria Elisabetta, Pathak, Amit, Pendleton, Yvonne J., Petrignani, Annemieke, Pino, Thomas, Puga, Elena, Rangwala, Naseem, Rapacioli, Mathias, Rho, Jeonghee, Ricca, Alessandra, Roman-Duval, Julia, Roser, Joseph, Roueff, Evelyne, Salama, Farid, Sales, Dinalva A., Sandstrom, Karin, Sarre, Peter, Sciamma-O'Brien, Ella, Sellgren, Kris, Shenoy, Sachindev S., Teyssier, David, Thomas, Richard D., Witt, Adolf N., Wootten, Alwyn, Ysard, Nathalie, Zettergren, Henning, Zhang, Yong, Zhang, Ziwei E., and Zhen, Junfeng
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
Mid-infrared emission features probe the properties of ionized gas, and hot or warm molecular gas. The Orion Bar is a frequently studied photodissociation region (PDR) containing large amounts of gas under these conditions, and was observed with the MIRI IFU aboard JWST as part of the "PDRs4All" program. The resulting IR spectroscopic images of high angular resolution (0.2") reveal a rich observational inventory of mid-IR emission lines, and spatially resolve the substructure of the PDR, with a mosaic cutting perpendicularly across the ionization front and three dissociation fronts. We extracted five spectra that represent the ionized, atomic, and molecular gas layers, and measured the most prominent gas emission lines. An initial analysis summarizes the physical conditions of the gas and the potential of these data. We identified around 100 lines, report an additional 18 lines that remain unidentified, and measured the line intensities and central wavelengths. The H I recombination lines originating from the ionized gas layer bordering the PDR, have intensity ratios that are well matched by emissivity coefficients from H recombination theory, but deviate up to 10% due contamination by He I lines. We report the observed emission lines of various ionization stages of Ne, P, S, Cl, Ar, Fe, and Ni, and show how certain line ratios vary between the five regions. We observe the pure-rotational H$_2$ lines in the vibrational ground state from 0-0 S(1) to 0-0 S(8), and in the first vibrationally excited state from 1-1 S(5) to 1-1 S(9). We derive H$_2$ excitation diagrams, and approximate the excitation with one thermal (~700 K) component representative of an average gas temperature, and one non-thermal component (~2700 K) probing the effect of UV pumping. We compare these results to an existing model for the Orion Bar PDR and highlight the differences with the observations., Comment: 26 pages, 12 figures, 3 tables. Submitted to A&A, under review (1st revision)
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- 2024
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36. Intense formation of secondary ultrafine particles from Amazonian vegetation fires and their invigoration of deep clouds and precipitation
- Author
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Shrivastava, Manish, Fan, Jiwen, Zhang, Yuwei, Rasool, Quazi Z, Zhao, Bin, Shen, Jiewen, Pierce, Jeffrey R, Jathar, Shantanu H, Akherati, Ali, Zhang, Jie, Zaveri, Rahul A, Gaudet, Brian, Liu, Ying, Andreae, Meinrat O, Pöhlker, Mira L, Donahue, Neil M, Wang, Yuan, and Seinfeld, John H
- Subjects
Earth Sciences ,Atmospheric Sciences ,Climate Action ,Earth sciences ,Environmental sciences - Published
- 2024
37. Survival disparities in non-Hispanic Black and White cervical cancer patients vary by histology and are largely explained by modifiable factors
- Author
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Kucera, Calen W, Chappell, Nicole P, Tian, Chunqiao, Richardson, Michael T, Tarney, Christopher M, Hamilton, Chad A, Chan, John K, Kapp, Daniel S, Leath, Charles A, Casablanca, Yovanni, Rojas, Christine, Sitler, Collin A, Wenzel, Lari, Klopp, Ann, Jones, Nathaniel L, Rocconi, Rodney P, Farley, John H, O'Connor, Timothy D, Shriver, Craig D, Bateman, Nicholas W, Conrads, Thomas P, Phippen, Neil T, Maxwell, G Larry, and Darcy, Kathleen M
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Biomedical and Clinical Sciences ,Oncology and Carcinogenesis ,Cancer ,Health Disparities ,Social Determinants of Health ,Clinical Research ,Cervical Cancer ,Minority Health ,Women's Health ,Humans ,Female ,Uterine Cervical Neoplasms ,White People ,Middle Aged ,Black or African American ,Aged ,Carcinoma ,Squamous Cell ,Adult ,Adenocarcinoma ,United States ,Healthcare Disparities ,Health Status Disparities ,Socioeconomic Factors ,Proportional Hazards Models ,Neoplasm Staging ,Cervical cancer ,Racial disparities ,Propensity score analysis ,Squamous cell carcinoma ,NCDB ,Paediatrics and Reproductive Medicine ,Oncology & Carcinogenesis ,Clinical sciences ,Oncology and carcinogenesis ,Reproductive medicine - Abstract
PurposeWe investigated racial disparities in survival by histology in cervical cancer and examined the factors contributing to these disparities.MethodsNon-Hispanic Black and non-Hispanic White (hereafter known as Black and White) patients with stage I-IV cervical carcinoma diagnosed between 2004 and 2017 in the National Cancer Database were studied. Survival differences were compared using Cox modeling to estimate hazard ratio (HR) or adjusted HR (AHR) and 95% confidence interval (CI). The contribution of demographic, socioeconomic and clinical factors to the Black vs White differences in survival was estimated after applying propensity score weighting in patients with squamous cell carcinoma (SCC) or adenocarcinoma (AC).ResultsThis study included 10,111 Black and 43,252 White patients with cervical cancer. Black patients had worse survival than White cervical cancer patients (HR = 1.40, 95% CI = 1.35-1.45). Survival disparities between Black and White patients varied significantly by histology (HR = 1.20, 95% CI = 1.15-1.24 for SCC; HR = 2.32, 95% CI = 2.12-2.54 for AC, interaction p
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- 2024
38. Chronic SIV-induced neuroinflammation disrupts CCR7+CD4+ T cell immunosurveillance in the rhesus macaque brain
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Elizaldi, Sonny R, Hawes, Chase E, Verma, Anil, Lakshmanappa, Yashavanth Shaan, Dinasarapu, Ashok R, Schlegel, Brent T, Rajasundaram, Dhivyaa, Li, Jie, Durbin-Johnson, Blythe P, Ma, Zhong-Min, Pal, Pabitra B, Beckman, Danielle, Ott, Sean, Raeman, Reben, Lifson, Jeffrey, Morrison, John H, and Iyer, Smita S
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Medical Microbiology ,Biomedical and Clinical Sciences ,Immunology ,Infectious Diseases ,Genetics ,Human Genome ,HIV/AIDS ,Neurosciences ,Sexually Transmitted Infections ,1.1 Normal biological development and functioning ,Underpinning research ,Animals ,Macaca mulatta ,Simian Acquired Immunodeficiency Syndrome ,Simian Immunodeficiency Virus ,CD4-Positive T-Lymphocytes ,Receptors ,CCR7 ,Brain ,Neuroinflammatory Diseases ,Immunologic Surveillance ,Simian immunodeficiency virus ,AIDS/HIV ,Adaptive immunity ,Inflammation ,Neurological disorders ,T cells ,Medical and Health Sciences ,Biological sciences ,Biomedical and clinical sciences ,Health sciences - Abstract
CD4+ T cells survey and maintain immune homeostasis in the brain, yet their differentiation states and functional capabilities remain unclear. Our approach, combining single-cell transcriptomic analysis, ATAC-Seq, spatial transcriptomics, and flow cytometry, revealed a distinct subset of CCR7+ CD4+ T cells resembling lymph node central memory (TCM) cells. We observed chromatin accessibility at the CCR7, CD28, and BCL-6 loci, defining molecular features of TCM. Brain CCR7+ CD4+ T cells exhibited recall proliferation and interleukin-2 production ex vivo, showcasing their functional competence. We identified the skull bone marrow as a local niche for these cells alongside CNS border tissues. Sequestering TCM cells in lymph nodes using FTY720 led to reduced CCR7+ CD4+ T cell frequencies in the cerebrospinal fluid, accompanied by increased monocyte levels and soluble markers indicating immune activation. In macaques chronically infected with SIVCL757 and experiencing viral rebound due to cessation of antiretroviral therapy, a decrease in brain CCR7+ CD4+ T cells was observed, along with increased microglial activation and initiation of neurodegenerative pathways. Our findings highlight a role for CCR7+ CD4+ T cells in CNS immune surveillance, and their decline during chronic SIV highlights their responsiveness to neuroinflammation.
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- 2024
39. Symmetry criteria for the equality of interior and exterior shape factors
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McKee, Kyle and Lienhard, John H.
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Physics - Classical Physics ,Mathematical Physics ,Mathematics - Classical Analysis and ODEs - Abstract
Lienhard (2019) reported that the shape factor of the interior of a simply-connected region ($\Omega$) is equal to that of its exterior ($\mathbb{R}^2\backslash\Omega$) under the same boundary conditions. In that study, numerical examples supported the claim in particular cases; for example, it was shown that for certain boundary conditions on circles and squares, the conjecture holds. In the present paper, we show that the conjecture is not generally true, unless some additional condition is met. We proceed by elucidating why the conjecture does in fact hold in all of the examples analysed by Lienhard. We thus deduce a simple criterion which, when satisfied, ensures the equality of interior and exterior shape factors in general. Our criterion notably relies on a beautiful and little-known symmetry method due to Hersch (1982) which we introduce in a tutorial manner.
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- 2024
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40. Characterization of starspots on a young M-dwarf K2-25: multi-band observations of stellar photometric variability and planetary transits
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Mori, Mayuko, Ikuta, Kai, Fukui, Akihiko, Narita, Norio, de Leon, Jerome P., Livingston, John H., Ikoma, Masahiro, Kawai, Yugo, Kawauchi, Kiyoe, Murgas, Felipe, Palle, Enric, Parviainen, Hannu, Rodríguez, Gareb Fernández, Terada, Yuka, Watanabe, Noriharu, and Tamura, Motohide
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Detailed atmospheric characterization of exoplanets by transmission spectroscopy requires careful consideration of stellar surface inhomogeneities induced by starspots. This effect is particularly problematic for planetary systems around M-dwarfs, and their spot properties are not fully understood. We investigated the stellar activity of the young M-dwarf K2-25 and its effect on transit observations of the sub-Neptune K2-25b. From multi-band monitoring observations of stellar brightness variability using ground-based telescopes and TESS, we found that the temperature difference between the spots and photosphere is <190 K and the spot covering fraction is <61% (2$\sigma$). We also investigated the effect of starspot activity using multi-epoch, multi-band transit observations. We rule out cases with extremely low spot temperatures and large spot covering fractions. The results suggest that spots could distort the transmission spectrum of K2-25b by as much as $\sim$100 ppm amplitude, corresponding to the precision of JWST/NIRSPEC of the target. Our study demonstrates that simultaneous multi-band observations with current instruments can constrain the spot properties of M-dwarfs with good enough precision to support atmospheric studies of young M-dwarf planets via transmission spectroscopy., Comment: 24 pages, 24 figures, Accepted for publication in MNRAS
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- 2024
41. Comments Concerning a Hypothetical Mesoscopic Dark Dimension
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Schwarz, John H.
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High Energy Physics - Theory ,Astrophysics - Cosmology and Nongalactic Astrophysics ,General Relativity and Quantum Cosmology - Abstract
Motivated by string-theoretic swampland conjectures, the existence of a dark fifth dimension, whose size is roughly 1 -- 10 microns, has been proposed. A great deal of supporting evidence has been presented, and definitive experimental tests are likely to be carried out. The basic idea is that the four-dimensional spacetime that we observe lives on a brane that is localized in the dark dimension. This short note points out that there are two distinct ways to realize such a scenario in string theory/M-theory. In the one considered previously the dark dimension is topologically a circle and our observable 4d spacetime is confined to a brane that is localized in a GUT-scale region of the circle. An alternative possibility is that the dark dimension is a line interval with branes attached at each end. This option would imply the existence of a parallel 4d spacetime microns away from us!, Comment: v2 and v3:added references and other improvements
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- 2024
42. A Framework to Calibrate a Semi-analytic Model of the First Stars and Galaxies to the Renaissance Simulations
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Hazlett, Ryan, Kulkarni, Mihir, Visbal, Eli, and Wise, John H.
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present a method that calibrates a semi-analytic model to the Renaissance Simulations, a suite of cosmological hydrodynamical simulations with high-redshift galaxy formation. This approach combines the strengths of semi-analytic techniques and hydrodynamical simulations, enabling the extension to larger volumes and lower redshifts inaccessible to simulations due to computational expense. Using a sample of Renaissance star formation histories (SFHs) from an average density region of the Universe, we construct a four parameter prescription for metal-enriched star formation characterized by an initial bursty stage followed by a steady stage where stars are formed at constant efficiencies. Our model also includes a treatment of Population III star formation where a minimum halo mass and log-normal distribution of stellar mass are adopted to match the numerical simulations. Star formation is generally well reproduced for halos with masses $\lesssim$$10^{9} M_{\mathrm{\odot}}$. Between $11
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- 2024
43. Efficient Adapter Tuning of Pre-trained Speech Models for Automatic Speaker Verification
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Sang, Mufan and Hansen, John H. L.
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Electrical Engineering and Systems Science - Audio and Speech Processing ,Computer Science - Machine Learning ,Computer Science - Sound - Abstract
With excellent generalization ability, self-supervised speech models have shown impressive performance on various downstream speech tasks in the pre-training and fine-tuning paradigm. However, as the growing size of pre-trained models, fine-tuning becomes practically unfeasible due to heavy computation and storage overhead, as well as the risk of overfitting. Adapters are lightweight modules inserted into pre-trained models to facilitate parameter-efficient adaptation. In this paper, we propose an effective adapter framework designed for adapting self-supervised speech models to the speaker verification task. With a parallel adapter design, our proposed framework inserts two types of adapters into the pre-trained model, allowing the adaptation of latent features within intermediate Transformer layers and output embeddings from all Transformer layers. We conduct comprehensive experiments to validate the efficiency and effectiveness of the proposed framework. Experimental results on the VoxCeleb1 dataset demonstrate that the proposed adapters surpass fine-tuning and other parameter-efficient transfer learning methods, achieving superior performance while updating only 5% of the parameters., Comment: Accepted to ICASSP 2024
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- 2024
44. A far-ultraviolet-driven photoevaporation flow observed in a protoplanetary disk
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Berné, Olivier, Habart, Emilie, Peeters, Els, Schroetter, Ilane, Canin, Amélie, Sidhu, Ameek, Chown, Ryan, Bron, Emeric, Haworth, Thomas J., Klaassen, Pamela, Trahin, Boris, Van De Putte, Dries, Alarcón, Felipe, Zannese, Marion, Abergel, Alain, Bergin, Edwin A., Bernard-Salas, Jeronimo, Boersma, Christiaan, Cami, Jan, Cuadrado, Sara, Dartois, Emmanuel, Dicken, Daniel, Elyajouri, Meriem, Fuente, Asunción, Goicoechea, Javier R., Gordon, Karl D., Issa, Lina, Joblin, Christine, Kannavou, Olga, Khan, Baria, Lacinbala, Ozan, Languignon, David, Gal, Romane Le, Maragkoudakis, Alexandros, Meshaka, Raphael, Okada, Yoko, Onaka, Takashi, Pasquini, Sofia, Pound, Marc W., Robberto, Massimo, Röllig, Markus, Schefter, Bethany, Schirmer, Thiébaut, Simmer, Thomas, Tabone, Benoit, Tielens, Alexander G. G. M., Vicente, Sílvia, Wolfire, Mark G., Aleman, Isabel, Allamandola, Louis, Auchettl, Rebecca, Baratta, Giuseppe Antonio, Baruteau, Clément, Bejaoui, Salma, Bera, Partha P., Black, John H., Boulanger, Francois, Bouwman, Jordy, Brandl, Bernhard, Brechignac, Philippe, Brünken, Sandra, Buragohain, Mridusmita, Burkhardt, Andrew, Candian, Alessandra, Cazaux, Stéphanie, Cernicharo, Jose, Chabot, Marin, Chakraborty, Shubhadip, Champion, Jason, Colgan, Sean W. J., Cooke, Ilsa R., Coutens, Audrey, Cox, Nick L. J., Demyk, Karine, Meyer, Jennifer Donovan, Engrand, Cécile, Foschino, Sacha, García-Lario, Pedro, Gavilan, Lisseth, Gerin, Maryvonne, Godard, Marie, Gottlieb, Carl A., Guillard, Pierre, Gusdorf, Antoine, Hartigan, Patrick, He, Jinhua, Herbst, Eric, Hornekaer, Liv, Jäger, Cornelia, Janot-Pacheco, Eduardo, Kaufman, Michael, Kemper, Francisca, Kendrew, Sarah, Kirsanova, Maria S., Knight, Collin, Kwok, Sun, Labiano, Álvaro, Lai, Thomas S. -Y., Lee, Timothy J., Lefloch, Bertrand, Petit, Franck Le, Li, Aigen, Linz, Hendrik, Mackie, Cameron J., Madden, Suzanne C., Mascetti, Joëlle, McGuire, Brett A., Merino, Pablo, Micelotta, Elisabetta R., Morse, Jon A., Mulas, Giacomo, Neelamkodan, Naslim, Ohsawa, Ryou, Paladini, Roberta, Palumbo, Maria Elisabetta, Pathak, Amit, Pendleton, Yvonne J., Petrignani, Annemieke, Pino, Thomas, Puga, Elena, Rangwala, Naseem, Rapacioli, Mathias, Ricca, Alessandra, Roman-Duval, Julia, Roueff, Evelyne, Rouillé, Gaël, Salama, Farid, Sales, Dinalva A., Sandstrom, Karin, Sarre, Peter, Sciamma-O'Brien, Ella, Sellgren, Kris, Shannon, Matthew J., Simonnin, Adrien, Shenoy, Sachindev S., Teyssier, David, Thomas, Richard D., Togi, Aditya, Verstraete, Laurent, Witt, Adolf N., Wootten, Alwyn, Ysard, Nathalie, Zettergren, Henning, Zhang, Yong, Zhang, Ziwei E., and Zhen, Junfeng
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Astrophysics - Astrophysics of Galaxies - Abstract
Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photo-dissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, impacting planet formation within the disks. We report JWST and Atacama Large Millimetere Array observations of a FUV-irradiated protoplanetary disk in the Orion Nebula. Emission lines are detected from the PDR; modelling their kinematics and excitation allows us to constrain the physical conditions within the gas. We quantify the mass-loss rate induced by the FUV irradiation, finding it is sufficient to remove gas from the disk in less than a million years. This is rapid enough to affect giant planet formation in the disk.
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- 2024
45. 3C 273 Host Galaxy with Hubble Space Telescope Coronagraphy
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Ren, Bin B., Fogarty, Kevin, Debes, John H., Meyer, Eileen T., Mo, Youbin, Mawet, Dimitri, Perrin, Marshall D., Ogle, Patrick M., and Sahlmann, Johannes
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The close-in regions of bright quasars' host galaxies have been difficult to image due to the overwhelming light from the quasars. With coronagraphic observations in visible light using the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope, we removed 3C 273 quasar light using color-matching reference stars. The observations revealed the host galaxy from 60" to 0.2" with nearly full angular coverage. Isophote modeling revealed a new core jet, a core blob, and multiple smaller-scale blobs within 2.5". The blobs could potentially be satellite galaxies or infalling materials towards the central quasar. Using archival STIS data, we constrained the apparent motion of its large scale jets over a 22 yr timeline. By resolving the 3C 273 host galaxy with STIS, our study validates the coronagraph usage on extragalactic sources in obtaining new insights into the central ~kpc regions of quasar hosts., Comment: 13 pages, 11 figures, 2 tables, A&A Letters accepted
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- 2024
46. Infrared Characterisation of Jupiter's Equatorial Disturbance Cycle
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Antuñano, Arrate, Fletcher, Leigh N., Orton, Glenn S., Melin, Henrik, Rogers, John H., Harrington, Joseph, Donnelly, Padraig T., Rowe-Gurney, Naomi, and Blake, James S. D.
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
We use an infrared dataset captured between 1984 and 2017 using several instruments and observatories to report five rare equatorial disturbances that completely altered the appearance of Jupiter's Equatorial Zone (EZ): the clearance of tropospheric clouds revealed a new 5-$\mu$m-bright band encircling the planet at the equator, accompanied by large 5-$\mu$m-bright filaments. Three events were observed in ground-based images in 1973, 1979 and 1992. We report and characterize for the first time the entire evolution of two new episodes of this unusual EZ state that presented their maximum 5-$\mu$m-brightness in December 1999 and February 2007, coinciding with a brown coloration south of the equator and with large bluish filaments and white plumes in the northern EZ at visible wavelengths. We characterize their typical infrared-bright lifetimes of 12-18 months, with possible periodicities of 6-8 or 13-14 years. We predict that a full-scale equatorial disturbance could occur in 2019-21.
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- 2024
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- View/download PDF
47. Development and validation of an artificial intelligence model to accurately predict spinopelvic parameters
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Harake, Edward S., Linzey, Joseph R., Jiang, Cheng, Joshi, Rushikesh S., Zaki, Mark M., Jones, Jaes C., Khalsa, Siri S., Lee, John H., Wilseck, Zachary, Joseph, Jacob R., Hollon, Todd C., and Park, Paul
- Subjects
Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Artificial Intelligence ,Computer Science - Machine Learning - Abstract
Objective. Achieving appropriate spinopelvic alignment has been shown to be associated with improved clinical symptoms. However, measurement of spinopelvic radiographic parameters is time-intensive and interobserver reliability is a concern. Automated measurement tools have the promise of rapid and consistent measurements, but existing tools are still limited by some degree of manual user-entry requirements. This study presents a novel artificial intelligence (AI) tool called SpinePose that automatically predicts spinopelvic parameters with high accuracy without the need for manual entry. Methods. SpinePose was trained and validated on 761 sagittal whole-spine X-rays to predict sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), T1-pelvic angle (T1PA), and L1-pelvic angle (L1PA). A separate test set of 40 X-rays was labeled by 4 reviewers, including fellowship-trained spine surgeons and a fellowship-trained radiologist with neuroradiology subspecialty certification. Median errors relative to the most senior reviewer were calculated to determine model accuracy on test images. Intraclass correlation coefficients (ICC) were used to assess inter-rater reliability. Results. SpinePose exhibited the following median (interquartile range) parameter errors: SVA: 2.2(2.3)mm, p=0.93; PT: 1.3(1.2){\deg}, p=0.48; SS: 1.7(2.2){\deg}, p=0.64; PI: 2.2(2.1){\deg}, p=0.24; LL: 2.6(4.0){\deg}, p=0.89; T1PA: 1.1(0.9){\deg}, p=0.42; and L1PA: 1.4(1.6){\deg}, p=0.49. Model predictions also exhibited excellent reliability at all parameters (ICC: 0.91-1.0). Conclusions. SpinePose accurately predicted spinopelvic parameters with excellent reliability comparable to fellowship-trained spine surgeons and neuroradiologists. Utilization of predictive AI tools in spinal imaging can substantially aid in patient selection and surgical planning., Comment: 10 pages, 5 figures, to appear in Journal of Neurosurgery: Spine
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- 2024
48. Gaussian Processes and Nested Sampling Applied to Kepler's Small Long-period Exoplanet Candidates
- Author
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Matesic, Michael R. B., Rowe, Jason F., Livingston, John H., Dholakia, Shishir, Jontof-Hutter, Daniel, and Lissauer, Jack J.
- Subjects
Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
There are more than 5000 confirmed and validated planets beyond the solar system to date, more than half of which were discovered by NASA's Kepler mission. The catalog of Kepler's exoplanet candidates has only been extensively analyzed under the assumption of white noise (i.i.d. Gaussian), which breaks down on timescales longer than a day due to correlated noise (point-to-point correlation) from stellar variability and instrumental effects. Statistical validation of candidate transit events becomes increasingly difficult when they are contaminated by this form of correlated noise, especially in the low-signal-to-noise (S/N) regimes occupied by Earth--Sun and Venus--Sun analogs. To diagnose small long-period, low-S/N putative transit signatures with few (roughly 3--9) observed transit-like events (e.g., Earth--Sun analogs), we model Kepler's photometric data as noise, treated as a Gaussian process, with and without the inclusion of a transit model. Nested sampling algorithms from the Python UltraNest package recover model evidences and maximum a posteriori parameter sets, allowing us to disposition transit signatures as either planet candidates or false alarms within a Bayesian framework., Comment: 15 pages, 9 figures, 2 tables, uses AASTeX631
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- 2024
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49. Characterization of K2-167 b and CALM, a new stellar activity mitigation method
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de Beurs, Zoë L., Vanderburg, Andrew, Thygesen, Erica, Rodriguez, Joseph E., Dumusque, Xavier, Mortier, Annelies, Malavolta, Luca, Buchhave, Lars A., Shallue, Christopher J., Zieba, Sebastian, Kreidberg, Laura, Livingston, John H., Haywood, R. D., Latham, David W., López-Morales, Mercedes, and Silva, André M.
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
We report precise radial velocity (RV) observations of HD 212657 (= K2-167), a star shown by K2 to host a transiting sub-Neptune-sized planet in a 10 day orbit. Using Transiting Exoplanet Survey Satellite (TESS) photometry, we refined the planet parameters, especially the orbital period. We collected 74 precise RVs with the HARPS-N spectrograph between August 2015 and October 2016. Although this planet was first found to transit in 2015 and validated in 2018, excess RV scatter originally limited mass measurements. Here, we measure a mass by taking advantage of reductions in scatter from updates to the HARPS-N Data Reduction System (2.3.5) and our new activity mitigation method called CCF Activity Linear Model (CALM), which uses activity-induced line shape changes in the spectra without requiring timing information. Using the CALM framework, we performed a joint fit with RVs and transits using EXOFASTv2 and find $M_p = 6.3_{-1.4}^{+1.4}$ $M_{\oplus}$ and $R_p = 2.33^{+0.17}_{-0.15}$ $R_{\oplus}$, which places K2-167 b at the upper edge of the radius valley. We also find hints of a secondary companion at a $\sim$ 22 day period, but confirmation requires additional RVs. Although characterizing lower-mass planets like K2-167 b is often impeded by stellar variability, these systems especially help probe the formation physics (i.e. photoevaporation, core-powered mass loss) of the radius valley. In the future, CALM or similar techniques could be widely applied to FGK-type stars, help characterize a population of exoplanets surrounding the radius valley, and further our understanding of their formation., Comment: 20 pages, 16 figures, accepted for publication in MNRAS
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- 2024
50. An Exploratory Assessment of LLM's Potential Toward Flight Trajectory Reconstruction Analysis
- Author
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Zhang, Qilei and Mott, John H.
- Subjects
Computer Science - Machine Learning ,Computer Science - Artificial Intelligence ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Large Language Models (LLMs) hold transformative potential in aviation, particularly in reconstructing flight trajectories. This paper investigates this potential, grounded in the notion that LLMs excel at processing sequential data and deciphering complex data structures. Utilizing the LLaMA 2 model, a pre-trained open-source LLM, the study focuses on reconstructing flight trajectories using Automatic Dependent Surveillance-Broadcast (ADS-B) data with irregularities inherent in real-world scenarios. The findings demonstrate the model's proficiency in filtering noise and estimating both linear and curved flight trajectories. However, the analysis also reveals challenges in managing longer data sequences, which may be attributed to the token length limitations of LLM models. The study's insights underscore the promise of LLMs in flight trajectory reconstruction and open new avenues for their broader application across the aviation and transportation sectors., Comment: 6 pages
- Published
- 2024
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