27,618 results on '"Cordova, A"'
Search Results
2. Generalized $T_e$([OIII])-$T_e$(HeI) Discrepancies in Ionized Nebulae: Possible Evidence of Case B Deviations and Temperature Inhomogeneities
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Méndez-Delgado, J. E., Skillman, E. D., Aver, E., Morisset, C., Esteban, C., García-Rojas, J., Kreckel, K., Rogers, N. S. J., Rosales-Ortega, F. F., Arellano-Córdova, K. Z., Flury, S. R., Reyes-Rodríguez, E., and Orte-García, M.
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Astrophysics - Astrophysics of Galaxies - Abstract
The physics of recombination lines (RLs) in the HeI singlet system is expected to be relatively simple, supported by accurate atomic models. We examine the intensities of HeI singlets $\lambda \lambda$3614, 3965, 5016, 6678, 7281 and the triplet HeI $\lambda$5876 in various types of ionized nebulae and compare them with theoretical predictions to test the validity of the ``Case B'' recombination scenario and the assumption of thermal homogeneity. Our analysis includes 85 spectra from Galactic and extragalactic HII regions, 90 from star-forming galaxies, and 218 planetary nebulae, all compiled by the DEep Spectra of Ionized REgions Database Extended (DESIRED-E) project. By evaluating the ratios HeI $\lambda$7281/$\lambda$6678 and HeI $\lambda$7281/$\lambda$5876, we determine $T_e$(HeI) and compare it with direct measurements of $T_e$([OIII] $\lambda$4363/$\lambda$5007). We find that $T_e$(HeI) is systematically lower than $T_e$([OIII]) across most objects and nebula types. Additionally, we identify a correlation between the abundance discrepancy factor (ADF(O$^{2+}$)) and the difference $T_e$([OIII]) - $T_e$(HeI) for planetary nebulae. We explore two potential explanations: photon loss from $n^1P \rightarrow 1^1S$ transitions and temperature inhomogeneities. Deviations from ``Case B'' may indicate photon absorption by HI rather than HeI and/or generalized ionizing photon escape, highlighting the need for detailed consideration of radiative transfer effects. If temperature inhomogeneities are widespread, identifying a common physical phenomenon affecting all ionized nebulae is crucial. Our results suggest that both scenarios can contribute to the observed discrepancies., Comment: Submitted to the AAS, comments and feedback from the community are welcome
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- 2024
3. Merian: A Wide-Field Imaging Survey of Dwarf Galaxies at z~0.06-0.10
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Danieli, Shany, Kado-Fong, Erin, Huang, Song, Luo, Yifei, Li, Ting S, Kelvin, Lee S, Leauthaud, Alexie, Greene, Jenny E., Mintz, Abby, Lin, Xiaojing, Li, Jiaxuan, Baldassare, Vivienne, Banerjee, Arka, Bhattacharyya, Joy, Blanco, Diana, Brooks, Alyson, Cai, Zheng, Chen, Xinjun, Cruz, Akaxia, Geda, Robel, Guan, Runquan, Johnson, Sean, Kannawadi, Arun, Kim, Stacy Y., Li, Mingyu, Lupton, Robert, Mace, Charlie, Medina, Gustavo E., Pan, Yue, Peter, Annika H. G., Read, Justin I., Rosado, Rodrigo Córdova, Seifert, Allen, Wasleske, Erik J., and Wick, Joseph
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Astrophysics - Astrophysics of Galaxies - Abstract
We present the Merian Survey, an optical imaging survey optimized for studying the physical properties of bright star-forming dwarf galaxies. Merian is carried out with two medium-band filters ($N708$ and $N540$, centered at $708$ and $540$ nm), custom-built for the Dark Energy Camera (DECam) on the Blanco telescope. Merian covers $\sim 750\,\mathrm{deg}^2$ of equatorial fields, overlapping with the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) wide, deep, and ultra-deep fields. When combined with the HSC-SSP imaging data ($grizy$), the new Merian DECam medium-band imaging allows for photometric redshift measurements via the detection of H$\rm\alpha$ and [OIII] line emission flux excess in the $N708$ and $N540$ filters, respectively, at $0.06
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- 2024
4. CLASSY XI: Tracing Neutral Gas Properties using UV Absorption Lines and 21-cm Observations
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Parker, Kaelee S., Berg, Danielle A., Gazagnes, Simon, Chisholm, John, James, Bethan L., Hayes, Matthew, Heckman, Timothy, Henry, Alaina, Berg, Michelle A., Arellano-Cordova, Karla Z., Xu, Xinfeng, Erb, Dawn K., Martin, Crystal L., Hu, Weida, Skillman, Evan D., McQuinn, Kristen B. W., Chen, Zuyi, and Stark, Dan P.
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Astrophysics - Astrophysics of Galaxies - Abstract
Rest-frame far-ultraviolet (FUV) observations from JWST are revolutionizing our understanding of the high-z galaxies that drove reionization and the mechanisms by which they accomplished it. To fully interpret these observations, we must be able to diagnose how properties of the interstellar medium (ISM; e.g., column density, covering fraction, outflow velocity) directly relate to the absorption features produced. Using the high-S/N and high-resolution FUV spectra of 45 nearby star-forming galaxies from CLASSY, we present the largest uniform, simultaneous characterization of neutral and low-ionization state (LIS) interstellar UV absorption lines (OI, SiII, SII, CII, AlII) across a wide range of galaxy properties. We also present 21-cm HI observations for 35 galaxies, multiple of which are gas-poor or non-detected, possibly indicating the onset of a post-starburst phase. We find that our simultaneous 1-component Voigt profile fits are capable of accurately modeling the LIS absorption for ~75% of galaxies, mitigating challenges associated with saturation, infilling, and degeneracies. While the most massive galaxies require additional components, our 1-component fits return average properties of the absorbing gas and follow the scaling relations described by a single gas cloud. We explore connections between LIS absorption and direct tracers of the neutral ISM (OI, Ly-alpha, HI 21-cm), finding that CII most closely traces the neutral gas trends while other ions exhibit weaker correlations. Given the challenges with directly observing HI at higher-z, we demonstrate that LIS absorption can be a powerful means to study the neutral ISM and present empirical relationships for predicting neutral gas properties., Comment: 25 pages with 16 figures and 2 tables. Long appendix with figure sets and tables. Accepted to ApJ
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- 2024
5. Enhancing Image Classification in Small and Unbalanced Datasets through Synthetic Data Augmentation
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De La Fuente, Neil, Majó, Mireia, Luzko, Irina, Córdova, Henry, Fernández-Esparrach, Gloria, and Bernal, Jorge
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
Accurate and robust medical image classification is a challenging task, especially in application domains where available annotated datasets are small and present high imbalance between target classes. Considering that data acquisition is not always feasible, especially for underrepresented classes, our approach introduces a novel synthetic augmentation strategy using class-specific Variational Autoencoders (VAEs) and latent space interpolation to improve discrimination capabilities. By generating realistic, varied synthetic data that fills feature space gaps, we address issues of data scarcity and class imbalance. The method presented in this paper relies on the interpolation of latent representations within each class, thus enriching the training set and improving the model's generalizability and diagnostic accuracy. The proposed strategy was tested in a small dataset of 321 images created to train and validate an automatic method for assessing the quality of cleanliness of esophagogastroduodenoscopy images. By combining real and synthetic data, an increase of over 18\% in the accuracy of the most challenging underrepresented class was observed. The proposed strategy not only benefited the underrepresented class but also led to a general improvement in other metrics, including a 6\% increase in global accuracy and precision., Comment: MICCAI 2024 (CLIP Workshop)
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- 2024
6. The Large Magellanic Cloud: expanding the low-mass parameter space of dark matter direct detection
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Reynoso-Cordova, Javier, Bozorgnia, Nassim, and Piro, Marie-Cécile
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High Energy Physics - Phenomenology ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
We investigate how the Large Magellanic Cloud (LMC) impacts the predicted signals in near-future direct detection experiments for non-standard dark matter (DM) interactions, using the Auriga cosmological simulations. We extract the local DM distribution of a simulated Milky Way-like halo that has an LMC analogue and study the expected signals in DarkSide-20k, SBC, DARWIN/XLZD, SuperCDMS, NEWS-G, and DarkSPHERE considering DM-nucleon effective interactions, as well as inelastic DM scattering. We find that the LMC causes substantial shifts in direct detection exclusion limits towards smaller cross sections and DM masses for all non-relativistic effective field theory (NREFT) operators, with the impact being highly pronounced for velocity-dependent operators at low DM masses. For inelastic DM, where the DM particle up-scatters to a heavier state, the LMC shifts the direct detection exclusion limits towards larger DM mass splitting and smaller cross sections. Thus, we show that the LMC significantly expands the parameter space that can be probed by direct detection experiments towards smaller DM-nucleon cross sections for all NREFT operators and larger values of mass splitting for inelastic DM., Comment: 23 pages, 11 figures, 2 tables
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- 2024
7. Cross-correlation of Luminous Red Galaxies with ML-selected AGN in HSC-SSP: Unobscured AGN residing in more massive halos
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Rosado, Rodrigo Córdova, Goulding, Andy D., Greene, Jenny E., Petter, Grayson C., Hickox, Ryan C., Kokron, Nickolas, Strauss, Michael A., Givans, Jahmour J., Toba, Yoshiki, and Henderson, Cassandra Starr
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Astrophysics - Astrophysics of Galaxies - Abstract
Active galactic nuclei (AGN) are the signposts of black hole growth, and likely play an important role in galaxy evolution. An outstanding question is whether AGN of different spectral types indicate different evolutionary stages in the coevolution of black holes and galaxies. We present the angular correlation function between an AGN sample selected from the Hyper Suprime Camera Subaru Strategic Program (HSC-SSP) optical + Wide-field Infrared Survey Explorer (WISE) mid-IR photometry, and a luminous red galaxy (LRG) sample from HSC-SSP. We investigate AGN clustering strength as a function of their luminosity and spectral features across three independent HSC fields totaling $\sim600\,{\rm deg^{2}}$, for $z\in0.6-1.2$ and AGN with $L_{6\mu m}>3\times10^{44}{\rm\,erg\,s^{-1}}$. There are $\sim28,500$ AGN and $\sim1.5$ million LRGs in our primary analysis. We determine the inferred average halo mass for the full AGN sample ($M_h \approx 10^{12.9}h^{-1}M_\odot$), and note that it does not evolve significantly as a function of redshift (over this narrow range) or luminosity. We find that, on average, unobscured AGN ($M_h \approx10^{13.3}h^{-1}M_\odot$) occupy $\sim4.5\times$ more massive halos than obscured AGN ($M_h \approx10^{12.6}h^{-1}M_\odot$), at $5\sigma$ statistical significance using 1-D uncertainties, and at $3\sigma$ using the full covariance matrix, suggesting a physical difference between unobscured and obscured AGN, beyond the line-of-sight viewing angle. Furthermore, we find evidence for a halo mass dependence on reddening level within the Type I AGN population, which could support the existence of a previously claimed dust-obscured phase in AGN-host galaxy coevolution. However, we also find that even quite small systematic shifts in the redshift distributions of the AGN sample could plausibly explain current and previously observed differences in $M_{h}$., Comment: 31 pages, 14 figures, submitted to ApJ
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- 2024
8. LHC beam monitoring via real-time hit reconstruction in the LHCb VELO pixel detector
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Passaro, Daniele, Cordova, Giulio, Lazzari, Federico, Graverini, Elena, Morello, Michael Joseph, and Punzi, Giovanni
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High Energy Physics - Experiment ,Physics - Instrumentation and Detectors - Abstract
The increasing computing power and bandwidth of programmable digital devices opens new possibilities in the field of real-time processing of HEP data. The LHCb collaboration is exploiting these technology advancements in various ways to enhance its capability for complex data reconstruction in real time. Amongst them is the real-time reconstruction of hits in the VELO pixel detector, by means of real-time cluster-finding embedded in the readout board firmware. This reconstruction, in addition to saving data-acquisition bandwidth and high-level trigger computing resources, also enables further useful applications in precision monitoring and diagnostics of LHC beam conditions. In fact, clusters of pixels, being more reliable and robust indications of physical particle hits than raw pixel counts, are also exempt from the complications associated to the reconstruction of tracks, that involves alignment issues and is sensitive to multi-layer efficiency products. In this paper, we describe the design and implementation of a flexible system embedded in the readout firmware of the VELO detector, allowing real-time measurement of cluster density in several parts of the detector simultaneously, and separately for every bunch ID, for every single LHC collision, without any slowdown of data acquisition. Quantitative applications of this system to luminosity measurement and beam monitoring are demonstrated., Comment: 4 pages, 5 figures, Proceedings of the ACAT 2024 conference
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- 2024
9. Gapped theories have torsion anomalies
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Córdova, Clay, Freed, Daniel S., and Teleman, Constantin
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High Energy Physics - Theory ,Condensed Matter - Strongly Correlated Electrons ,Mathematical Physics - Abstract
We prove special cases of a general conjecture: If an invertible field theory admits a projectively topological boundary theory, then it has finite order in the abelian group of invertible field theories. One can substitute `gapped' for `projectively topological'. Our proofs use evaluations of a field theory in parametrized families., Comment: 8 pages
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- 2024
10. S-Matrix Bootstrap and Non-Invertible Symmetries
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Copetti, Christian, Cordova, Lucia, and Komatsu, Shota
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High Energy Physics - Theory ,Condensed Matter - Strongly Correlated Electrons ,High Energy Physics - Phenomenology - Abstract
We initiate the S-matrix bootstrap analysis of theories with non-invertible symmetries in (1+1) dimensions. Our previous work showed that crossing symmetry of S-matrices in such theories is modified, with modification characterized by the fusion category data. By imposing unitarity, symmetry and the modified crossing, we constrain the space of consistent S-matrices, identifying integrable theories with non-invertible symmetries at the cusps of allowed regions. We also extend the modified crossing rules to cases where vacua transform in non-regular representations of fusion category, utilizing a connection to a dual category $\mathscr C^{*}_{\mathscr{M}}$ and Symmetry Topological Field Theory (SymTFT). This highlights the utility of SymTFT in the analysis of scattering amplitudes., Comment: 33 pages plus appendices, v2: references added
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- 2024
11. Representation Theory of Solitons
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Cordova, Clay, Holfester, Nicholas, and Ohmori, Kantaro
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High Energy Physics - Theory ,Condensed Matter - Strongly Correlated Electrons ,Mathematics - Quantum Algebra - Abstract
Solitons in two-dimensional quantum field theory exhibit patterns of degeneracies and associated selection rules on scattering amplitudes. We develop a representation theory that captures these intriguing features of solitons. This representation theory is based on an algebra we refer to as the "strip algebra", $\textrm{Str}_{\mathcal{C}}(\mathcal{M})$, which is defined in terms of the non-invertible symmetry, $\mathcal{C},$ a fusion category, and its action on boundary conditions encoded by a module category, $\mathcal{M}$. The strip algebra is a $C^*$-weak Hopf algebra, a fact which can be elegantly deduced by quantizing the three-dimensional Drinfeld center TQFT, $\mathcal{Z}(\mathcal{C}),$ on a spatial manifold with corners. These structures imply that the representation category of the strip algebra is also a unitary fusion category which we identify with a dual category $\mathcal{C}_{\mathcal{M}}^{*}.$ We present a straightforward method for analyzing these representations in terms of quiver diagrams where nodes are vacua and arrows are solitons and provide examples demonstrating how the representation theory reproduces known degeneracies and selection rules of soliton scattering. Our analysis provides the general framework for analyzing non-invertible symmetry on manifolds with boundary and applies both to the case of boundaries at infinity, relevant to particle physics, and boundaries at finite distance, relevant in conformal field theory or condensed matter systems., Comment: 59 pages, 111 figures, v2: added references, minor typos corrected, revised discussion of relation to Tube algebra
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- 2024
12. Quantum energy teleportation in phase space quantum mechanics
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Sanchez-Cordova, M. M. and Berra-Montiel, Jasel
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Quantum Physics ,Mathematical Physics - Abstract
In this paper, we investigate the Quantum Energy Teleportation protocol within the phase space formulation of quantum mechanics. By employing the Wigner quasi-probability distribution and the star product, we show that the teleported energy is proportional to the amount of entanglement present in the initial ground state. Further, we introduce the Husimi $Q$-function on a Bloch coherent state in order to determine the Wehrl entropy of the system. Finally, the Wherl entropy enable us to compute the consumption of coherence and entanglement throughout the protocol., Comment: 13 pages, no figures
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- 2024
13. Vesiculobullous cutaneous larva migrans in the absence of domestic dogs and cats. Successful treatment with oral ivermectin
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Calvopina, Manuel, Lozano-Alvarez, Karla, Enriquez-Morillo, Sandra, and Cordova-Calisto, Ignacio
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- 2024
14. GaSI: A Wide-Gap Non-centrosymmetric Helical Crystal.
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Dold, Kaitlyn, Cordova, Dmitri, Singsen, Sirisak, Nguyen, Joseph, Milligan, Griffin, Marracci, Marcus, Yao, Ze-Fan, Ziller, Joseph, Fishman, Dmitry, Lee, Elizabeth, and Arguilla, Maxx
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The complex non-centrosymmetric and chiral nature of helical structures endow materials that possess such motifs with unusual properties. However, despite their ubiquity in biological and organic systems, there is a severe lack of inorganic crystals that display helicity in extended lattices, where these unusual properties are expected to be most pronounced. Here, we report a new inorganic helical structure, gallium sulfur iodide (GaSI), within the exfoliable class of III-VI-VII (1:1:1) one-dimensional (1D) van der Waals (vdW) crystals. Through detailed structural analyses, including single-crystal X-ray diffraction, electron microscopy, and density functional theory (DFT), we elucidate the apparent noncrystallographic screw axis and the first example of an atomic scale helical structure bearing a squircular cross-section in GaSI. Crystallizing in the non-centrosymmetric P4̅ space group, we found that GaSI crystals exhibit pronounced second-harmonic generation. From diffuse reflectance spectroscopy, GaSI displays a sizeable bandgap of 3.69 eV, owing tostrong covalent interactions arising from the smaller sulfur atoms within the helix core. These results position GaSI as a promising exfoliable nonlinear optical material across a broad optical window.
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- 2024
15. Bonding-Directed Crystallization of Ultra-Long One-Dimensional NbS3 van der Waals Nanowires.
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Lopez, Diana, Zhou, Yinong, Cordova, Dmitri, Milligan, Griffin, Ogura, Kaleolani, Wu, Ruqian, and Arguilla, Maxx
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The rediscovery of one-dimensional (1D) and quasi-1D (q-1D) van der Waals (vdW) crystals ushered the realization of nascent physical properties in 1D that are suitable for applications in photonics, electronics, and sensing. However, despite renewed interest in the creation and understanding of the physical properties of 1D and q-1D vdW crystals, the lack of accessible synthetic pathways for growing well-defined nanostructures that extend across several length scales remains. Using the highly anisotropic 1D vdW NbS3-I crystal as a model phase, we present a catalyst-free and bottom-up synthetic approach to access ultralong nanowires, with lengths reaching up to 7.9 mm and with uniform thicknesses ranging from 13 to 160 nm between individual nanowires. Control over the synthetic parameters enabled the modulation of intra- and interchain growth modalities to selectively yield only 1D nanowires or quasi-2D nanoribbons. Comparative synthetic and density functional theory (DFT) studies with a closely related nondimerized phase, ZrS3, show that the unusual preferential growth along 1D can be correlated to the strongly anisotropic bonding and dimeric nature of NbS3-I.
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- 2024
16. Fast control of the transverse structure of a light beam using acousto-optic modulators
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Jabbari, Mahdieh Chartab, Li, Cheng, Liu, Xialin, Córdova-Castro, R. Margoth, Braverman, Boris, Upham, Jeremy, and Boyd, Robert W.
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Physics - Optics - Abstract
Fast, reprogrammable control over the transverse structure of light beams plays an essential role in applications such as structured illumination microscopy, optical trapping, and quantum information processing. Existing technologies, such as liquid crystal on silicon spatial light modulators (LCoS-SLMs) and digital micromirror devices (DMDs), suffer from limited refresh rates, low damage thresholds, and high insertion loss. Acousto-optic modulators (AOMs) can resolve the above issues, as they typically handle higher laser power and offer lower insertion loss. By effectively mapping the temporal radio-frequency (RF) waveforms onto the spatial diffraction patterns of the optical field, individual AOMs have been shown to generate one-dimensional (1D) spatial modes at a pixel refresh rate of nearly 20 MHz. We extend this concept to enable fast modulation in a two-dimensional (2D) space using a double-AOM scheme. We demonstrate the generation of 2D Hermite-Gaussian (HG_nm) modes with an average fidelity of 81%, while the highest-order mode generated, HG_53, retains a fidelity of 56%.
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- 2024
17. Non-invertible symmetries in finite group gauge theory
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Cordova, Clay, Costa, Davi B., and Hsin, Po-Shen
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Condensed Matter - Strongly Correlated Electrons ,High Energy Physics - Theory ,Mathematics - Quantum Algebra - Abstract
We investigate the invertible and non-invertible symmetries of topological finite group gauge theories in general spacetime dimensions, where the gauge group can be Abelian or non-Abelian. We focus in particular on the 0-form symmetry. The gapped domain walls that generate these symmetries are specified by boundary conditions for the gauge fields on either side of the wall. We investigate the fusion rules of these symmetries and their action on other topological defects including the Wilson lines, magnetic fluxes, and gapped boundaries. We illustrate these constructions with various novel examples, including non-invertible electric-magnetic duality symmetry in 3+1d $\mathbb{Z}_2$ gauge theory, and non-invertible analogs of electric-magnetic duality symmetry in non-Abelian finite group gauge theories. In particular, we discover topological domain walls that obey Fibonacci fusion rules in 2+1d gauge theory with dihedral gauge group of order 8. We also generalize the Cheshire string defect to analogous defects of general codimensions and gauge groups and show that they form a closed fusion algebra., Comment: 55 pages, 20 figures. V2: fixed figures misprints and typos
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- 2024
18. Empirical calibration for helium abundance determinations in Active Galactic Nuclei
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Dors, O. L., Almeida, G. C., Oliveira, C. B., Flury, S. R., Riffel, R., Riffel, R. A., Cardaci, M. V., Hägele, G. F., Ilha, G. S., Krabbe, A. C., Arellano-Córdova, K. Z., Santos, P. C., and Morais, I. N.
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Astrophysics - Astrophysics of Galaxies - Abstract
For the first time, a calibration between the HeI $\lambda5876$/H$\beta$ emission line ratio and the helium abundance $y$=12+log(He/H) for Narrow line regions (NLRs) of Seyfert~2 Active Galactic Nuclei (AGN) is proposed. In this context, observational data (taken from the SDSS-DR15 and from the literature) and direct abundance estimates (via the $T_{\rm e}$-method) for a sample of 65 local ($z \: < \: 0.2$) Seyfert~2 nuclei are considered. The resulting calibration estimates the $y$ abundance with an average uncertainty of 0.02 dex. Applying our calibration to spectroscopic data containing only strong emission lines, it yields a helium abundance distribution similar to that obtained via the $T_{\rm e}$-method. Some cautions must be considered to apply our calibration for Seyfert~2 nuclei with high values of electron temperature ($\gtrsim\: 20\,000$ K) or ionization parameter ($\log U > -2.0$)., Comment: Accepted for publication as Letter in MNRAS
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- 2024
19. CHAOS VIII: Far-Ultraviolet Spectra of M101 and The Impact of Wolf-Rayet Stars
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Berg, Danielle A., Skillman, Evan D., Chisholm, John, Pogge, Richard W., Gazagnes, Simon, Rogers, Noah S. J., Erb, Dawn K., Arellano-Córdova, Karla Z., Leitherer, Claus, Appel, Jackie, and Moustakas, John
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Astrophysics - Astrophysics of Galaxies - Abstract
We investigate the stellar and nebular properties of 9 H II regions in the spiral galaxy M101 with far-ultraviolet (FUV; ~900-2000 \r{A}) and optical (~3200-10000 \r{A}) spectra. We detect significant C III] 1907,1909 nebular emission in 7 regions, but O III] 1666 only in the lowest-metallicity region. We produce new analytic functions of the carbon ICF as a function of metallicity in order to perform a preliminary C/O abundance analysis. The FUV spectra also contain numerous stellar emission and P-Cygni features that we fit with luminosity-weighted combinations of single-burst Starburst99 and BPASS models. We find that the best-fit Starburst99 models closely match the observed very-high-ionization P-Cygni features, requiring very-hot, young (~< 3 Myr), metal-enriched massive stars. The youngest stellar populations are strongly correlated with broad He II emission, nitrogen Wolf-Rayet (WR) FUV and optical spectral features, and enhanced N/O gas abundances. Thus, the short-lived WR phase may be driving excess emission in several N P-Cygni wind features (955 \r{A}, 991 \r{A}, 1720 \r{A}) that bias the stellar continuum fits to higher metallicities relative to the gas-phase metallicities. Accurate characterization of these H II regions requires additional inclusion of WR stars in the stellar population synthesis models. Our FUV spectra demonstrate that the ~900-1200 \r{A} FUV can provide a strong test-bed for future WR atmosphere and evolution models., Comment: 24 ages, 12 figures, accepted to ApJ
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- 2024
20. Deep learning lattice gauge theories
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Apte, Anuj, Ashmore, Anthony, Cordova, Clay, and Huang, Tzu-Chen
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High Energy Physics - Lattice ,Condensed Matter - Disordered Systems and Neural Networks ,Condensed Matter - Strongly Correlated Electrons ,Computer Science - Machine Learning ,High Energy Physics - Theory - Abstract
Monte Carlo methods have led to profound insights into the strong-coupling behaviour of lattice gauge theories and produced remarkable results such as first-principles computations of hadron masses. Despite tremendous progress over the last four decades, fundamental challenges such as the sign problem and the inability to simulate real-time dynamics remain. Neural network quantum states have emerged as an alternative method that seeks to overcome these challenges. In this work, we use gauge-invariant neural network quantum states to accurately compute the ground state of $\mathbb{Z}_N$ lattice gauge theories in $2+1$ dimensions. Using transfer learning, we study the distinct topological phases and the confinement phase transition of these theories. For $\mathbb{Z}_2$, we identify a continuous transition and compute critical exponents, finding excellent agreement with existing numerics for the expected Ising universality class. In the $\mathbb{Z}_3$ case, we observe a weakly first-order transition and identify the critical coupling. Our findings suggest that neural network quantum states are a promising method for precise studies of lattice gauge theory.
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- 2024
21. Direct estimates of nitrogen abundance for Seyfert 2 nuclei
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Dors, O. L., Cardaci, M. V., Hägele, G. F., Valerdi, M., Ilha, G. S., Oliveira, C. B., Riffel, R. A., Flury, S. R., Arellano-Córdova, K. Z., Storchi-Bergmann, T., Riffel, R., Almeida, G. C., and Morais, I. N.
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Astrophysics - Astrophysics of Galaxies - Abstract
We derive the nitrogen and oxygen abundances in the Narrow Line Regions (NLRs) of a sample of 38 local ($z \: < \: 0.4$) Seyfert~2 nuclei. For that, we consider narrow optical emission line intensities and direct estimates of the electron temperatures ($T_{\rm e}$-method). We find nitrogen abundances in the range $7.6 \: < \: \rm 12+log(N/H) \: < \: 8.6$ (mean value $8.06\pm0.22$) or $\rm 0.4 \: < \: (N/N_{\odot}) \: < 4.7$, in the metallicity regime $8.3 \: < \: \rm 12+log(O/H) \: < \: 9.0$. Our results indicate that the dispersion in N/H abundance for a fixed O/H value in AGNs is in agreement with that for disc \ion{H}{ii} regions with similar metallicity. We show that Seyfert~2 nuclei follow a similar (N/O)-(O/H) relation to the one followed by star-forming objects. Finally, we find that active galaxies called as 'nitrogen-loud' observed at very high redshift ($z \: > \: 5$) show N/O values in consonance with those derived for local NLRs. This result indicates that the main star-formation event is completed in the early evolution stages of active galaxies., Comment: Submitted to MNRAS. Comments are welcome!
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- 2024
22. Towards a Distributed Platform for Normative Reasoning and Value Alignment in Multi-Agent Systems
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Garcia-Bohigues, Miguel, Cordova, Carmengelys, Taverner, Joaquin, Palanca, Javier, del Val, Elena, and Argente, Estefania
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Computer Science - Multiagent Systems - Abstract
This paper presents an extended version of the SPADE platform, which aims to empower intelligent agent systems with normative reasoning and value alignment capabilities. Normative reasoning involves evaluating social norms and their impact on decision-making, while value alignment ensures agents' actions are in line with desired principles and ethical guidelines. The extended platform equips agents with normative awareness and reasoning capabilities based on deontic logic, allowing them to assess the appropriateness of their actions and make informed decisions. By integrating normative reasoning and value alignment, the platform enhances agents' social intelligence and promotes responsible and ethical behaviors in complex environments.
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- 2024
23. The JWST EXCELS survey: Too much, too young, too fast? Ultra-massive quiescent galaxies at 3 < z < 5
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Carnall, A. C., Cullen, F., McLure, R. J., McLeod, D. J., Begley, R., Donnan, C. T., Dunlop, J. S., Shapley, A. E., Rowlands, K., Almaini, O., Arellano-Córdova, K. Z., Barrufet, L., Cimatti, A., Ellis, R. S., Grogin, N. A., Hamadouche, M. L., Illingworth, G. D., Koekemoer, A. M., Leung, H. -H., Lovell, C. C., Pérez-González, P. G., Santini, P., Stanton, T. M., and Wild, V.
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Astrophysics - Astrophysics of Galaxies - Abstract
We report ultra-deep, medium-resolution spectroscopic observations for 4 quiescent galaxies with log$_{10}(M_*/\mathrm{M_\odot})>11$ at $3 < z < 5$. These data were obtained with JWST NIRSpec as part of the Early eXtragalactic Continuum and Emission Line Science (EXCELS) survey, which we introduce in this work. The first two galaxies are newly selected from PRIMER UDS imaging, both at $z=4.62$ and separated by $860$ pkpc on the sky, within a larger structure for which we confirm several other members. Both formed at $z\simeq8-10$. These systems could plausibly merge by the present day to produce a local massive elliptical galaxy. The other two ultra-massive quiescent galaxies are previously known at $z=3.99$ and $3.19$, with the latter (ZF-UDS-7329) having been the subject of debate as potentially too old and too massive to be accommodated by the $\Lambda$-CDM halo-mass function. Both exhibit high stellar metallicities, and for ZF-UDS-7329 we are able to measure the $\alpha-$enhancement, obtaining [Mg/Fe] = $0.42^{+0.19}_{-0.17}$. We finally evaluate whether these 4 galaxies are consistent with the $\Lambda$-CDM halo-mass function using an extreme value statistics approach. We find that the $z=4.62$ objects and the $z=3.19$ object are unlikely within our area under the assumption of standard stellar fractions ($f_*\simeq0.1-0.2$). However, these objects roughly align with the most massive galaxies expected under the assumption of 100 per cent conversion of baryons to stars ($f_*$=1). Our results suggest extreme galaxy formation physics during the first billion years, but no conflict with $\Lambda$-CDM cosmology., Comment: 25 pages, 10 figures, accepted for publication in MNRAS
- Published
- 2024
24. The NIRVANDELS Survey: the stellar and gas-phase mass-metallicity relations of star-forming galaxies at z = 3.5
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Stanton, T. M., Cullen, F., McLure, R. J., Shapley, A. E., Arellano-Córdova, K. Z., Begley, R., Amorín, R., Barrufet, L., Calabrò, A., Carnall, A. C., Cirasuolo, M., Dunlop, J. S., Donnan, C. T., Hamadouche, M. L., Liu, F. -Y., McLeod, D. J., Pentericci, L., Pozzetti, L., Sanders, R. L., Scholte, D., and Topping, M. W.
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Astrophysics - Astrophysics of Galaxies - Abstract
We present determinations of the gas-phase and stellar metallicities of a sample of 65 star-forming galaxies at $z \simeq 3.5$ using rest-frame far-ultraviolet (FUV) spectroscopy from the VANDELS survey in combination with follow-up rest-frame optical spectroscopy from VLT/KMOS and Keck/MOSFIRE. We infer gas-phase oxygen abundances ($Z_{\mathrm{g}}$; tracing O/H) via strong optical nebular lines and stellar iron abundances ($Z_{\star}$; tracing Fe/H) from full spectral fitting to the FUV continuum. Our sample spans the stellar mass range $8.5 < \mathrm{log}(M_{\star}/\mathrm{M}_{\odot}) < 10.5$ and shows clear evidence for both a stellar and gas-phase mass-metallicity relation (MZR). We find that our O and Fe abundance estimates both exhibit a similar mass-dependence, such that $\mathrm{Fe/H}\propto M_{\star}^{0.30\pm0.11}$ and $\mathrm{O/H}\propto M_{\star}^{0.32\pm0.09}$. At fixed $M_{\star}$ we find that, relative to their solar values, O abundances are systematically larger than Fe abundances (i.e., $\alpha$-enhancement).We estimate an average enhancement of $\mathrm{(O/Fe)} = 2.65 \pm 0.16 \times \mathrm{(O/Fe)_\odot}$ which appears to be independent of $M_{\star}$. We employ analytic chemical evolution models to place a constraint on the strength of galactic-level outflows via the mass-outflow factor ($\eta$). We show that outflow efficiencies that scale as $\eta \propto M_{\star}^{-0.32}$ can simultaneously explain the functional form of of the stellar and gas-phase MZR, as well as the degree of $\alpha$-enhancement at fixed Fe/H. Our results add further evidence to support a picture in which $\alpha$-enhanced abundance ratios are ubiquitous in high-redshift star-forming galaxies, as expected for young systems whose interstellar medium is primarily enriched by core-collapse supernovae., Comment: 18 pages, 10 figures, 4 tables, accepted in MNRAS
- Published
- 2024
25. Chaco Canyon Dig Unearths Ethical Concerns
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Claw, Katrina G., Lippert, Dorothy, Bardill, Jessica, Cordova, Anna, Fox, Keolu, Yracheta, Joseph M., Bader, Alyssa C., Bolnick, Deborah A., Malhi, Ripan S., TallBear, Kimberly, Garrison, Nanibaa' A., and Garrison, Nanibaa' A.
- Published
- 2018
26. A RAB7A phosphoswitch coordinates Rubicon Homology protein regulation of Parkin-dependent mitophagy.
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Tudorica, Dan, Basak, Bishal, Puerta Cordova, Alexia, Khuu, Grace, Rose, Kevin, Lazarou, Michael, Holzbaur, Erika, and Hurley, James
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Mitophagy ,Humans ,rab7 GTP-Binding Proteins ,Phosphorylation ,Ubiquitin-Protein Ligases ,Protein Serine-Threonine Kinases ,rab GTP-Binding Proteins ,HeLa Cells ,Protein Binding ,Intracellular Signaling Peptides and Proteins ,Autophagy-Related Proteins ,Mitochondria ,HEK293 Cells - Abstract
Activation of PINK1 and Parkin in response to mitochondrial damage initiates a response that includes phosphorylation of RAB7A at Ser72. Rubicon is a RAB7A binding negative regulator of autophagy. The structure of the Rubicon:RAB7A complex suggests that phosphorylation of RAB7A at Ser72 would block Rubicon binding. Indeed, in vitro phosphorylation of RAB7A by TBK1 abrogates Rubicon:RAB7A binding. Pacer, a positive regulator of autophagy, has an RH domain with a basic triad predicted to bind an introduced phosphate. Consistent with this, Pacer-RH binds to phosho-RAB7A but not to unphosphorylated RAB7A. In cells, mitochondrial depolarization reduces Rubicon:RAB7A colocalization whilst recruiting Pacer to phospho-RAB7A-positive puncta. Pacer knockout reduces Parkin mitophagy with little effect on bulk autophagy or Parkin-independent mitophagy. Rescue of Parkin-dependent mitophagy requires the intact pRAB7A phosphate-binding basic triad of Pacer. Together these structural and functional data support a model in which the TBK1-dependent phosphorylation of RAB7A serves as a switch, promoting mitophagy by relieving Rubicon inhibition and favoring Pacer activation.
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- 2024
27. Functionalization and Structural Evolution of Conducting Quasi-One-Dimensional Chevrel-Type Telluride Nanocrystals.
- Author
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Ogura, Kaleolani, Cordova, Dmitri, Aoki, Toshihiro, Milligan, Griffin, Yao, Ze-Fan, and Arguilla, Maxx
- Abstract
Interfacing organic molecular groups with well-defined inorganic lattices, especially in low dimensions, enables synthetic routes for the rational manipulation of both their local or extended lattice structures and physical properties. While appreciably studied in two-dimensional systems, the influence of surface organic substituents on many known and emergent one-dimensional (1D) and quasi-1D (q-1D) crystals has remained underexplored. Herein, we demonstrate the surface functionalization of bulk and nanoscale Chevrel-like q-1D ionic crystals using In2Mo6Te6, a predicted q-1D Dirac semimetal, as the model phase. Using a series of alkyl ammonium (-NR4+; R = H, methyl, ethyl, butyl, and octyl) substituents with varying chain lengths, we demonstrate the systematic expansion of the intrachain c-axis direction and the contraction of the interchain a/b-axis direction with longer chain substituents. Additionally, we demonstrate the systematic expansion of the intrachain c-axis direction and the contraction of the interchain a/b-axis direction as the alkyl chain substituents become longer using a combination of powder X-ray diffraction and Raman experiments. Beyond the structural modulation that the substituted groups can impose on the lattice, we also found that the substitution of ammonium-based groups on the surface of the nanocrystals resulted in selective suspension in aqueous (NH4+-functionalized) or organic solvents (NOc4+-functionalized), imparted fluorescent character (Rhodamine B-functionalized), and modulated the electrical conductivity of the nanocrystal ensemble. Altogether, our results underscore the potential of organic-inorganic interfacing strategies to tune the structural and physical properties of rediscovered Chevrel-type q-1D ionic solids and open opportunities for the development of surface-addressable building blocks for hybrid electronic and optoelectronic devices at the nanoscale.
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- 2024
28. Quiescent or dusty? Unveiling the nature of extremely red galaxies at $z>3$
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Barrufet, L., Oesch, P., Marques-Chaves, R., Arellano-Cordova, K., Baggen, J. F. W., Carnall, A. C., Cullen, F., Dunlop, J. S., Gottumukkala, R., Fudamoto, Y., Illingworth, G. D., Magee, D., McLure, R. J., McLeod, D. J., Michałowski, M. J., Stefanon, M., van Dokkum, P. G., and Weibel, A.
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Astrophysics - Astrophysics of Galaxies - Abstract
The advent of the JWST has revolutionised our understanding of high-redshift galaxies. In particular, the NIRCam instrument on-board JWST has revealed a population of Hubble Space Telescope (HST)-dark galaxies that had previously evaded optical detection, potentially due to significant dust obscuration, quiescence, or simply extreme redshift. Here, we present the first NIRSpec spectra of 23 HST-dark galaxies ($\mathrm{H-F444W>1.75}$), unveiling their nature and physical properties. This sample includes both dusty and quiescent galaxies with spectroscopic data from NIRSpec/PRISM, providing accurate spectroscopic redshifts with $\mathrm{\overline{z}_{spec} = 4.1 \pm 0.7}$. The spectral features demonstrate that, while the majority of HST-dark galaxies are dusty, a substantial fraction, $\mathrm{13^{+9}_{-6} \%}$, are quiescent. For the dusty galaxies, we have quantified the dust attenuation using the Balmer decrement ($\mathrm{H\alpha / H\beta}$), finding attenuations $\mathrm{A_{V} > 2\ mag}$. We find that HST-dark dusty galaxies are $\mathrm{H\alpha}$ emitters with equivalent widths spanning the range $\mathrm{ 68 A < EW_{H\alpha} < 550 A }$, indicative of a wide range of recent star-formation activity. Whether dusty or quiescent, we find that HST-dark galaxies are predominantly massive, with 85\% of the galaxies in the sample having masses $\mathrm{log(M_{*}/M_{\odot}) > 9.8}$. This pilot NIRSpec program reveals the diverse nature of HST-dark galaxies and highlights the effectiveness of NIRSpec/PRISM spectroscopic follow-up in distinguishing between dusty and quiescent galaxies and properly quantifying their physical properties. Upcoming research utilising higher-resolution NIRSpec data and combining JWST with ALMA observations will enhance our understanding of these enigmatic and challenging sources., Comment: 13 pages, 11 figures
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- 2024
29. The JWST-PRIMAL Legacy Survey. A JWST/NIRSpec reference sample for the physical properties and Lyman-$\alpha$ absorption and emission of $\sim 500$ galaxies at $z=5.5-13.4$
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Heintz, K. E., Brammer, G. B., Watson, D., Oesch, P. A., Keating, L. C., Hayes, M. J., Abdurro'uf, Arellano-Córdova, K. Z., Carnall, A. C., Christiansen, C. R., Cullen, F., Davé, R., Dayal, P., Ferrara, A., Finlator, K., Fynbo, J. P. U., Flury, S. R., Gelli, V., Gillman, S., Gottumukkala, R., Gould, K., Greve, T. R., Hardin, S. E., Hsiao, T. Y. -Y, Hutter, A., Jakobsson, P., Killi, M., Khosravaninezhad, N., Laursen, P., Lee, M. M., Magdis, G. E., Matthee, J., Naidu, R. P., Narayanan, D., Pollock, C., Prescott, M., Rusakov, V., Shuntov, M., Sneppen, A., Smit, R., Tanvir, N. R., Terp, C., Toft, S., Valentino, F., Vijayan, A. P., Weaver, J. R., Wise, J. H., and Witstok, J.
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
One of the surprising early findings with JWST has been the discovery of a strong "roll-over" or a softening of the absorption edge of Ly$\alpha$ in a large number of galaxies at ($z\gtrsim 6$), in addition to systematic offsets from photometric redshift estimates and fundamental galaxy scaling relations. This has been interpreted as damped Ly$\alpha$ absorption (DLA) wings from high column densities of neutral atomic hydrogen (HI), signifying major gas accretion events in the formation of these galaxies. To explore this new phenomenon systematically, we assemble the JWST/NIRSpec PRImordial gas Mass AssembLy (PRIMAL) legacy survey of 494 galaxies at $z=5.5-13.4$. We characterize this benchmark sample in full and spectroscopically derive the galaxy redshifts, metallicities, star-formation rates, and ultraviolet slopes. We define a new diagnostic, the Ly$\alpha$ damping parameter $D_{\rm Ly\alpha}$ to measure and quantify the Ly$\alpha$ emission strength, HI fraction in the IGM, or local HI column density for each source. The JWST-PRIMAL survey is based on the spectroscopic DAWN JWST Archive (DJA-Spec). All the software, reduced spectra, and spectroscopically derived quantities and catalogs are made publicly available in dedicated repositories. The fraction of strong galaxy DLAs are found to be in the range $65-95\%$ at $z>5.5$. The fraction of strong Ly$\alpha$ emitters (LAEs) is found to increase with decreasing redshift, in qualitative agreement with previous observational results, and are predominantly associated with low-metallicity and UV faint galaxies. By contrast, strong DLAs are observed in galaxies with a variety of intrinsic physical properties. Our results indicate that strong DLAs likely reflect a particular early assembly phase of reionization-era galaxies, at which point they are largely dominated by pristine HI gas accretion. [abridged], Comment: 20 pages, 18 figures, 3 tables. Submitted to A&A. Comments welcome! All data and catalogs are available through the DAWN JWST Archive (DJA): https://dawn-cph.github.io/dja/ and https://github.com/keheintz/jwst-primal
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- 2024
30. CLASSY IX: The Chemical Evolution of the Ne, S, Cl, and Ar Elements
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Arellano-Córdova, Karla Z., Berg, Danielle A., Mingozzi, Matilde, James, Bethan L., Rogers, Noah S. J., Skillman, Evan D., Cullen, Fergus, Alexander, Ryan, Amorín, Ricardo O., Chisholm, John, Hayes, Matthew, Heckman, Timothy, Hernandez, Svean, Kumari, Nimisha, Leitherer, Claus, Martin, Crystal L., Maseda, Michael, Nanayakkara, Themiya, Parker, Kaelee, Ravindranath, Swara, Strom, Alisson L., Vincenzo, Fiorenzo, and Wofford, Aida
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
To study the chemical evolution across cosmic epochs, we investigate Ne, S, Cl, and Ar abundance patterns in the COS Legacy Archive Spectroscopic SurveY (CLASSY). CLASSY comprises local star-forming galaxies (0.02 < z < 0.18) with enhanced star-formation rates, making them strong analogues to high-z star-forming galaxies. With direct measurements of electron temperature, we derive accurate ionic abundances for all elements and assess ionization correction factors (ICFs) to account for unseen ions and derive total abundances. We find Ne/O, S/O, Cl/O, and Ar/O exhibit constant trends with gas-phase metallicity for 12+log(O/H) < 8.5 but significant correlation for Ne/O and Ar/O with metallicity for 12+log(O/H) > 8.5, likely due to ICFs. Thus, applicability of the ICFs to integrated spectra of galaxies could bias results, underestimating true abundance ratios. Using CLASSY as a local reference, we assess the evolution of Ne/O, S/O, and Ar/O in galaxies at z>3, finding no cosmic evolution of Ne/O, while the lack of direct abundance determinations for S/O and Ar/O can bias the interpretation of the evolution of these elements. We determine the fundamental metallicity relationship (FMR) for CLASSY and compare to the high-redshift FMR, finding no evolution. Finally, we perform the first mass-neon relationship analysis across cosmic epochs, finding a slight evolution to high Ne at later epochs. The robust abundance patterns of CLASSY galaxies and their broad range of physical properties provide essential benchmarks for interpreting the chemical enrichment of the early galaxies observed with the JWST., Comment: Accepted for publication in The Astrophysical Journal. 20 pages (main body), 10 figures, 6 Tables
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- 2024
31. Particle-Soliton Degeneracies from Spontaneously Broken Non-Invertible Symmetry
- Author
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Cordova, Clay, García-Sepúlveda, Diego, and Holfester, Nicholas
- Subjects
High Energy Physics - Theory ,Condensed Matter - Strongly Correlated Electrons ,Mathematics - Quantum Algebra - Abstract
We study non-invertible topological symmetry operators in massive quantum field theories in (1+1) dimensions. In phases where this symmetry is spontaneously broken we show that the particle spectrum often has degeneracies dictated by the non-invertible symmetry and we deduce a procedure to determine the allowed multiplets. These degeneracies are robust predictions and do not require integrability or other special features of renormalization group flows. We exhibit these conclusions in examples where the spectrum is known, recovering soliton and particle degeneracies. For instance, the Tricritical Ising model deformed by the subleading Z2 odd operator flows to a gapped phase with two degenerate vacua. This flow enjoys a Fibonacci fusion category symmetry which implies a threefold degeneracy of its particle states, relating the mass of solitons interpolating between vacua and particles supported in a single vacuum., Comment: 43 pages, 2 figures, 1 table, v2: added references, minor typos corrected
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- 2024
32. Non-Invertible Symmetries, Anomalies and Scattering Amplitudes
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Copetti, Christian, Cordova, Lucia, and Komatsu, Shota
- Subjects
High Energy Physics - Theory ,Condensed Matter - Strongly Correlated Electrons ,High Energy Physics - Phenomenology - Abstract
We show that crossing symmetry of S-matrices is modified in certain theories with non-invertible symmetries or anomalies. Focusing on integrable flows to gapped phases in two dimensions, we find that S-matrices derived previously from the bootstrap approach are incompatible with non-invertible symmetries along the flow. We present consistent alternatives, which however violate standard crossing symmetry and obey modified rules dictated by fusion categories. We extend these rules to theories with discrete anomalies., Comment: 7 pages plus supplemental material, v2: references added, typos corrected
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- 2024
33. JWST PRIMER: A new multi-field determination of the evolving galaxy UV luminosity function at redshifts $\mathbf{z \simeq 9-15}$
- Author
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Donnan, C. T., McLure, R. J., Dunlop, J. S., McLeod, D. J., Magee, D., Arellano-Córdova, K. Z., Barrufet, L., Begley, R., Bowler, R. A. A., Carnall, A. C., Cullen, F., Ellis, R. S., Fontana, A., Illingworth, G. D., Grogin, N. A., Hamadouche, M. L., Koekemoer, A. M., Liu, F. -Y., Mason, C., Santini, P., and Stanton, T. M.
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
We present a new determination of the evolving galaxy UV luminosity function (LF) over the redshift range $8.5
8.5)>0.05$) to undertake a statistical calculation of the UV LF. Our new measurements span $\simeq4$ magnitudes in UV luminosity at $z=9-12.5$, placing new constraints on both the shape and evolution of the LF at early times. Our measurements yield a new estimate of the early evolution of cosmic star-formation rate density ($\rho_{\rm{SFR}}$) confirming the gradual decline deduced from early JWST studies, at least out to $z \simeq 12$. Finally we show that the observed early evolution of the galaxy UV LF (and $\rho_{\rm{SFR}}$) can be reproduced in a ${\rm \Lambda}$CDM Universe, with no change in dust properties or star-formation efficiency required out to $z \simeq 12$. Instead, a progressive trend towards younger stellar population ages can reproduce the observations, and the typical ages required at $z \simeq$ 8, 9, 10, and 11 all converge on $\simeq 380-330$ Myr after the Big Bang, indicative of a rapid emergence of early galaxies at $z \simeq 12 - 13$. This is consistent with the first indications of a steeper drop-off in $\rho_{\rm{SFR}}$ we find beyond $z \simeq 13$, possibly reflecting the rapid evolution of the halo mass function at earlier times., Comment: 15 pages, 9 figures, accepted for publication in MNRAS - Published
- 2024
34. Effect of temperature and copper doping on the heterogeneous Fenton-like activity of Cu$_x$Fe$_{3-x}$O$_4$ nanoparticles
- Author
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Nuñez, Nahuel, Lima Jr., Enio, Mansilla, Marcelo Vásquez, Goya, Gerardo F., Gallo-Cordova, Álvaro, Morales, María del Puerto, and Winkler, Elin L.
- Subjects
Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Ferrite nanoparticles serve as potent heterogeneous Fenton-like catalysts, producing reactive oxygen species (ROS) for decomposing organic pollutants. We investigated the impact of temperature and copper content on the catalytic activity of nanoparticles with different oxidation states of iron. Via solvothermal synthesis, we fabricated copper-doped magnetite (Cu$_x$Fe$_{3-x}$O$_4$) with a Fe$^{2+}$/Fe ratio ~0.33 for the undoped system. Using a microwave-assisted method, we produced copper-doped oxidized ferrites, yielding a Fe$^{2+}$/Fe ratio of ~0.11 for the undoped nanoparticles. The ROS generated by the catalyst were identified and quantified by electron paramagnetic resonance, while optical spectroscopy allowed us to evaluate its effectiveness for the degradation of a model organic dye. At room temperature, the magnetite nanoparticles exhibited the most $\cdot$OH radical production and achieved almost 90% dye discoloration in 2 hours. This efficiency decreased with increasing Cu concentration, concurrently with a decrease in $\cdot$OH generation. Conversely, above room temperature, Cu-doped nanoparticles significantly enhance the dye degradation, reaching 100% discoloration at 90$^\circ$C. This enhancement is accompanied by a systematic increase in the kinetic constants, obtained from reaction equations, with Cu doping. This study highlights the superior stability and high-temperature catalytic advantages of copper ferrite holding promise for enhancing the performance of nanocatalysts for decomposing organic contaminants., Comment: 40 pages, 11 figures
- Published
- 2024
- Full Text
- View/download PDF
35. Non-Invertible Peccei-Quinn Symmetry and the Massless Quark Solution to the Strong CP Problem
- Author
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Cordova, Clay, Hong, Sungwoo, and Koren, Seth
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Theory - Abstract
We consider theories of gauged quark flavor and identify non-invertible Peccei-Quinn symmetries arising from fractional instantons when the resulting gauge group has non-trivial global structure. Such symmetries exist solely because the Standard Model has the same numbers of generations as colors, $N_g = N_c$. This leads us to a massless down-type quark solution to the strong CP problem in an ultraviolet $SU(9)$ theory of quark color-flavor unification. We show how the CKM flavor structure and weak CP violation can be generated without upsetting our solution., Comment: 38 pages + appendices and references, 6 figures, 8 tables
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- 2024
36. Netload Range Cost Curves for a Transmission-Aware Distribution System Planning under DER Growth Uncertainty
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Cordova, Samuel, Moreira, Alexandre, and Heleno, Miguel
- Subjects
Mathematics - Optimization and Control - Abstract
In the face of a substantial and uncertain growth of behind-the-meter Distributed Energy Resources (DERs), utilities and regulators are currently in the search for new network planning strategies for facilitating an efficient Transmission & Distribution (T&D) coordination. In this context, here we propose a novel distribution system planning methodology to facilitate coordinated planning exercises with transmission system planners through the management of long-term DER growth uncertainty and its impact on the substation netload. The proposed approach is based on the design of a transmission-aware distribution planning model embedding DER growth uncertainty, which is used to determine a "menu" of secure distribution network upgrade options with different associated costs and peak netload guarantees observed from the transmission-side, referred here as Netload Range Cost Curves (NRCCs). NRCCs can provide a practical approach for coordinating T&D planning exercises, as these curves can be integrated into existing transmission planning workflows, and specify a direct incentive for distribution planners to evaluate peak netload reduction alternatives in their planning process. We perform computational experiments based on a realistic distribution network that demonstrate the benefits and applicability of our proposed planning approach.
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- 2024
37. HIERONYMIELLA PERUVIANA (AMARYLLIDACEAE, AMARYLLIDOIDEAE, EUSTEPHIEAE) : A NEW SPECIES AND FIRST RECORD OF THE GENUS FOR THE FLORA OF PERU
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Huaylla, Hibert, Slanis, Alberto C., and Llalla-Cordova, Olimpia
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- 2024
38. Pathogen Index in Freshwater drum (Aplodinotus grunniens R.) from the Usumacinta River in Southeastern Mexico
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Martinez-Morales, Leydi D., Hernandez-Gomez, Raul E., Mendoza-Franco, Edgar F., and Valenzuela-Cordova, I.
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- 2024
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39. Atomically precise inorganic helices with a programmable irrational twist
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Cordova, Dmitri Leo Mesoza, Chua, Kenneth, Kerr, Tyler A., Aoki, Toshihiro, Knez, David, Skorupskii, Grigorii, Lopez, Diana, Ziller, Joseph, Fishman, Dmitry A., and Arguilla, Maxx Q.
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- 2024
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40. Targeting the chromatin binding of exportin-1 disrupts NFAT and T cell activation
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Chen, Yi Fan, Ghazala, Maryam, Friedrich, Ryan M., Cordova, Brittany A., Petroze, Frederick N., Srinivasan, Ramya, Allan, Kevin C., Yan, David F., Sax, Joel L., Carr, Kelley, Tomchuck, Suzanne L., Fedorov, Yuriy, Huang, Alex Y., Desai, Amar B., and Adams, Drew J.
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- 2024
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41. Clinical Education: Addressing Prior Trauma and Its Impacts in Medical Settings
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McBain, Sacha A. and Cordova, Matthew J.
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- 2024
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42. Dialogues About Race: Utilization of Experiential Antiracist Training for Healthcare Providers
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Monteiro, Delmira, Burrell, II, Larry E., and Cordova, Matthew J.
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- 2024
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43. Identification of Single-Nucleotide Polymorphisms in Differentially Expressed Genes Favoring Soybean Meal Tolerance in Higher-Growth Zebrafish (Danio rerio)
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Ulloa, Pilar E., Jilberto, Felipe, Lam, Natalia, Rincón, Gonzalo, Valenzuela, Luis, Cordova-Alarcón, Valentina, Hernández, Adrián J., Dantagnan, Patricio, Ravanal, Maria Cristina, Elgueta, Sebastian, and Araneda, Cristian
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- 2024
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44. Analysis of Raise Boring with Grouting as an Optimal Method for Ore Pass Construction in Incompetent Rock Mass—A Case Study
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Rojas, Cluber, Anani, Angelina, Cordova, Eduardo, Nyaaba, Wedam, Wellman, Edward, and Adewuyi, Sefiu O.
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- 2024
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45. A Heuristic Methodology for Economic and Geomechanical Optimization in Sublevel Open Stoping Mining Method
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Cordova, Diogo Peixoto, Zingano, Andre Cezar, and Gonçalves, Italo Gomes
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- 2024
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46. Assessing the effectiveness of Interleukin-2 therapy in experimental type 1 diabetes
- Author
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Luo, Zhengkang, Mejia-Cordova, Mariela, Hamze, Nour, Berggren, Elin, Chopra, Saloni, Safi, Bilal, Blixt, Martin, Sandler, Stellan, and Singh, Kailash
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- 2024
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47. Calibrating Wrist-Worn Accelerometers for Physical Activity Assessment in Preschoolers: Machine Learning Approaches
- Author
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Li, Shiyu, Howard, Jeffrey T, Sosa, Erica T, Cordova, Alberto, Parra-Medina, Deborah, and Yin, Zenong
- Subjects
Medicine - Abstract
BackgroundPhysical activity (PA) level is associated with multiple health benefits during early childhood. However, inconsistency in the methods for quantification of PA levels among preschoolers remains a problem. ObjectiveThis study aimed to develop PA intensity cut points for wrist-worn accelerometers by using machine learning (ML) approaches to assess PA in preschoolers. MethodsWrist- and hip-derived acceleration data were collected simultaneously from 34 preschoolers on 3 consecutive preschool days. Two supervised ML models, receiver operating characteristic curve (ROC) and ordinal logistic regression (OLR), and one unsupervised ML model, k-means cluster analysis, were applied to establish wrist-worn accelerometer vector magnitude (VM) cut points to classify accelerometer counts into sedentary behavior, light PA (LPA), moderate PA (MPA), and vigorous PA (VPA). Physical activity intensity levels identified by hip-worn accelerometer VM cut points were used as reference to train the supervised ML models. Vector magnitude counts were classified by intensity based on three newly established wrist methods and the hip reference to examine classification accuracy. Daily estimates of PA were compared to the hip-reference criterion. ResultsIn total, 3600 epochs with matched hip- and wrist-worn accelerometer VM counts were analyzed. All ML approaches performed differently on developing PA intensity cut points for wrist-worn accelerometers. Among the three ML models, k-means cluster analysis derived the following cut points: ≤2556 counts per minute (cpm) for sedentary behavior, 2557-7064 cpm for LPA, 7065-14532 cpm for MPA, and ≥14533 cpm for VPA; in addition, k-means cluster analysis had the highest classification accuracy, with more than 70% of the total epochs being classified into the correct PA categories, as examined by the hip reference. Additionally, k-means cut points exhibited the most accurate estimates on sedentary behavior, LPA, and VPA as the hip reference. None of the three wrist methods were able to accurately assess MPA. ConclusionsThis study demonstrates the potential of ML approaches in establishing cut points for wrist-worn accelerometers to assess PA in preschoolers. However, the findings from this study warrant additional validation studies.
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- 2020
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48. Nanoparticle-directed bimodal crystallization of the quasi-1D van der Waals phase, Bi4I4.
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Allison, Steven, Cordova, Dmitri, Hasib, Maham, Aoki, Toshihiro, and Arguilla, Maxx
- Abstract
Anisotropy often yields unexpected structures and properties in the solid state. In van der Waals (vdW) solids comprised of 1D or quasi-1D (q-1D) building blocks, anisotropy in both intra- and inter-chain directions results in an abundance of crystalline packing motifs and drastically altered physical states. Among these, structurally and chemically complex 1D/q-1D vdW solids that display topologically protected states, unique optical properties, and enhanced electrical transport properties in 1D are sought after owing to their potential as building blocks for next-generation quantum devices that approach the sub-nanometer regime. Yet, the access to such facet- and edge-specific physical states is still limited by the stochastic nature of micromechanical exfoliation. Here, we demonstrate that the representative Bi4I4 phase, an established pnictohalide q-1D vdW topological insulator in the bulk, can be crystallized from the vapor phase either into well-defined nanowires or quasi-2D nanosheets. We find that gold nanoparticles (Au NPs) on the growth substrate, in conjunction with the highly anisotropic structure of Bi4I4 common to many q-1D vdW crystals, direct the dimensionality of high-purity Bi4I4 nanostructures. Systematic variation of Au NP diameters, Bi : I precursor ratios, and growth-deposition temperatures reveal that Au NPs generally act as nucleation sites for vapor-solid (VS) growth of Bi4I4 nanowires. Strikingly, post-synthesis analyses of the elemental composition of 20 nm Au NPs on the substrate surface show an equisotichiometric 1 : 1 ratio of Bi to I within the Au NP that triggers the vapor-liquid-solid (VLS) growth of [001]-oriented quasi-2D nanosheets comprised of laterally-ordered [Bi4I4]n chains along the perpendicular [100] direction. We rationalize the observed bimodal growth pathways and the morphologically distinct nanostructures based on crystallization habits and orientations of the nanostructures, Bi : I ratios in the resulting Au NPs post-synthesis, and the orientation of stereochemically active Bi lone pairs between adjacent chains. We anticipate that these growth pathways are adaptable to the synthesis of emergent halide- and chalcogen-based 1D vdW nanocrystals with diverse physical and quantum properties.
- Published
- 2024
49. Clinical variants paired with phenotype: A rich resource for brain gene curation.
- Author
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Chopra, Maya, Savatt, Juliann, Bingaman, Taylor, Good, Molly, Morgan, Alexis, Cooney, Caitlin, Rossel, Allison, VanHoute, Bryanna, Cordova, Ineke, Mahida, Sonal, Lanzotti, Virginia, Baldridge, Dustin, Gurnett, Christina, Piven, Joseph, Hazlett, Heather, Pomeroy, Scott, Sahin, Mustafa, Payne, Philip, Riggs, Erin, and Constantino, John
- Subjects
Autism ,Gene curation ,Intellectual disability ,Neurodevelopmental disorders ,Variant of uncertain significance ,Humans ,Genetic Variation ,Databases ,Genetic ,Genetic Testing ,Phenotype ,Brain - Abstract
PURPOSE: Clinically ascertained variants are under-utilized in neurodevelopmental disorder research. We established the Brain Gene Registry (BGR) to coregister clinically identified variants in putative brain genes with participant phenotypes. Here, we report 179 genetic variants in the first 179 BGR registrants and analyze the proportion that were novel to ClinVar at the time of entry and those that were absent in other disease databases. METHODS: From 10 academically affiliated institutions, 179 individuals with 179 variants were enrolled into the BGR. Variants were cross-referenced for previous presence in ClinVar and for presence in 6 other genetic databases. RESULTS: Of 179 variants in 76 genes, 76 (42.5%) were novel to ClinVar, and 62 (34.6%) were absent from all databases analyzed. Of the 103 variants present in ClinVar, 37 (35.9%) were uncertain (ClinVar aggregate classification of variant of uncertain significance or conflicting classifications). For 5 variants, the aggregate ClinVar classification was inconsistent with the interpretation from the BGR site-provided classification. CONCLUSION: A significant proportion of clinical variants that are novel or uncertain are not shared, limiting the evidence base for new gene-disease relationships. Registration of paired clinical genetic test results with phenotype has the potential to advance knowledge of the relationships between genes and neurodevelopmental disorders.
- Published
- 2024
50. Non-Invertible Symmetry in Calabi-Yau Conformal Field Theories
- Author
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Cordova, Clay and Rizi, Giovanni
- Subjects
High Energy Physics - Theory - Abstract
We construct examples of non-invertible global symmetries in two-dimensional superconformal field theories described by sigma models into Calabi-Yau target spaces. Our construction provides some of the first examples of non-invertible symmetry in irrational conformal field theories. Our approach begins at a Gepner point in the conformal manifold where the sigma model specializes to a rational conformal field theory and we can identify all supersymmetric topological Verlinde lines. By deforming away from this special locus using exactly marginal operators, we then identify submanifolds in moduli space where some non-invertible symmetry persists. For instance, along ten-dimensional loci in the complex structure moduli space of quintic Calabi-Yau threefolds there is a symmetry characterized by a Fibonacci fusion category. The symmetries we identify provide new constraints on spectra and correlation functions. As an application we show how they constrain conformal perturbation theory, consistent with recent results about scaling dimensions in the K3 sigma model near its Gepner point., Comment: 66 pages, 1 figure
- Published
- 2023
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