226,173 results on '"Carr A"'
Search Results
2. A Simulated Galaxy Laboratory: Exploring the Observational Effects on UV Spectral Absorption Line Measurements
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Jennings, R. Michael, Henry, Alaina, Mauerhofer, Valentin, Heckman, Timothy, Scarlata, Claudia, Carr, Cody, Xu, Xinfeng, Huberty, Mason, Gazagnes, Simon, Jaskot, Anne E., Blaizot, Jeremy, Verhamme, Anne, Flury, Sophia R., Saldana-Lopez, Alberto, Hayes, Matthew J., and Trebitsch, Maxime
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Ultraviolet absorption line spectroscopy is a sensitive diagnostic for the properties of interstellar and circumgalactic gas. Down-the-barrel observations, where the absorption is measured against the galaxy itself, are commonly used to study feedback from galactic outflows and to make predictions about the leakage of HI ionizing photons into the intergalactic medium. Nonetheless, the interpretation of these observations is challenging and observational compromises are often made in terms of signal-to-noise, spectral resolution, or the use of stacking analyses. In this paper, we present a novel quantitative assessment of UV absorption line measurement techniques by using mock observations of a hydrodynamical simulation. We use a simulated galaxy to create 22,500 spectra in the commonly used SiII lines while also modeling the signal-to-noise and spectral resolution of recent rest-frame UV galaxy surveys at both high and low redshifts. We show that the residual flux of absorption features is easily overestimated for single line measurements and for stacked spectra. Additionally, we explore the robustness of the partial covering model for estimating column densities from spectra and find under-predictions on average of 1.25 dex. We show that the under-prediction is likely caused by high-column-density sight-lines that are optically-thick to dust making them invisible in UV spectra., Comment: 27 pages, 18 figures, Accepted to ApJ
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- 2024
3. Scaling Transformers for Low-Bitrate High-Quality Speech Coding
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Parker, Julian D, Smirnov, Anton, Pons, Jordi, Carr, CJ, Zukowski, Zack, Evans, Zach, and Liu, Xubo
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Electrical Engineering and Systems Science - Audio and Speech Processing ,Computer Science - Artificial Intelligence ,Computer Science - Machine Learning ,Computer Science - Sound ,Electrical Engineering and Systems Science - Signal Processing - Abstract
The tokenization of speech with neural audio codec models is a vital part of modern AI pipelines for the generation or understanding of speech, alone or in a multimodal context. Traditionally such tokenization models have concentrated on low parameter-count architectures using only components with strong inductive biases. In this work we show that by scaling a transformer architecture with large parameter count to this problem, and applying a flexible Finite Scalar Quantization (FSQ) based bottleneck, it is possible to reach state-of-the-art speech quality at extremely low bit-rates of $400$ or $700$ bits-per-second. The trained models strongly out-perform existing baselines in both objective and subjective tests.
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- 2024
4. Improved Background Estimation for Gas Plume Identification in Hyperspectral Images
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Jarman, Scout, Hampel-Arias, Zigfried, Carr, Adra, and Moon, Kevin R.
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Electrical Engineering and Systems Science - Image and Video Processing ,Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
Longwave infrared (LWIR) hyperspectral imaging can be used for many tasks in remote sensing, including detecting and identifying effluent gases by LWIR sensors on airborne platforms. Once a potential plume has been detected, it needs to be identified to determine exactly what gas or gases are present in the plume. During identification, the background underneath the plume needs to be estimated and removed to reveal the spectral characteristics of the gas of interest. Current standard practice is to use ``global" background estimation, where the average of all non-plume pixels is used to estimate the background for each pixel in the plume. However, if this global background estimate does not model the true background under the plume well, then the resulting signal can be difficult to identify correctly. The importance of proper background estimation increases when dealing with weak signals, large libraries of gases of interest, and with uncommon or heterogeneous backgrounds. In this paper, we propose two methods of background estimation, in addition to three existing methods, and compare each against global background estimation to determine which perform best at estimating the true background radiance under a plume, and for increasing identification confidence using a neural network classification model. We compare the different methods using 640 simulated plumes. We find that PCA is best at estimating the true background under a plume, with a median of 18,000 times less MSE compared to global background estimation. Our proposed K-Nearest Segments algorithm improves median neural network identification confidence by 53.2%., Comment: 13 pages, 10 figures, submitted and under review to IEEE Transactions on Geoscience and Remote Sensing
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- 2024
5. The effect of color-coding on students' perception of learning in introductory mechanics
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Thomas, Brianna S. Dillon, Carr, Scott, and Guo, Siming
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Physics - Physics Education - Abstract
We designed three color-coding schemes to identify related information across representations and to differentiate distinct information within a representation in slide-based instruction for calculus-based introductory mechanics. We found that students had generally favorable opinions on the use of color and that the few negative criticisms are easily addressed through minor modifications to implementation. Without having the color-coding schemes pointed out to them, a modest but consistent minority of students who found color helpful also described the color-coding schemes implemented, and about a quarter described the use of color in physics contexts as helpful even if they did not describe color-coding. We found that students particularly favored using color in mathematics and color-coding used to identify related variables, verbal definitions, and diagram elements. We additionally found that on average 40% of students found color to be helpful in matching and connecting related information or in separating and distinguishing distinct information, which were the motivating reasons for employing the color-coding schemes.
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- 2024
6. Beyond the Safety Bundle: Auditing the Helpful and Harmless Dataset
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Chehbouni, Khaoula, Carr, Jonathan Colaço, More, Yash, Cheung, Jackie CK, and Farnadi, Golnoosh
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Computer Science - Computation and Language ,Computer Science - Computers and Society - Abstract
In an effort to mitigate the harms of large language models (LLMs), learning from human feedback (LHF) has been used to steer LLMs towards outputs that are intended to be both less harmful and more helpful. Despite the widespread adoption of LHF in practice, the quality of this feedback and its effectiveness as a safety mitigation technique remain unclear. This study addresses these issues by auditing the widely-used Helpful and Harmless (HH) dataset by Anthropic. Our work includes: (1) a thorough investigation of the dataset's content through both manual and automated evaluation; (2) experiments demonstrating the dataset's impact on models' safety; and (3) an analysis of the 100 most influential papers citing this dataset. Through our audit, we showcase how conceptualization failures and quality issues identified in the HH dataset can create additional harms by leading to disparate safety behaviors across demographic groups. Our findings highlight the need for more nuanced, context-sensitive approaches to safety mitigation in LLMs., Comment: Prepared for conference submission
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- 2024
7. Outcomes from a Workshop on a National Center for Quantum Education
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Barnes, Edwin, Bennett, Michael B., Boltasseva, Alexandra, Borish, Victoria, Brown, Bennett, Carr, Lincoln D., Ceballos, Russell R., Dukes, Faith, Easton, Emily W., Economou, Sophia E., Edwards, E. E., Finkelstein, Noah D., Fracchiolla, C., Franklin, Diana, Freericks, J. K., Goss, Valerie, Hannum, Mark, Holincheck, Nancy, Kelly, Angela M., Lanes, Olivia, Lewandowski, H. J., Matsler, Karen Jo, Mercurio, Emily, Montaño, Inès, Murdock, Maajida, Peltz, Kiera, Perron, Justin K., Richardson, Christopher J. K., Rosenberg, Jessica L., Ross, Richard S., Ryu, Minjung, Samuel, Raymond E., Schrode, Nicole, Schwamberger, Susan, Searles, Thomas A., Singh, Chandralekha, Tingle, Alexandra, and Zwickl, Benjamin M.
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Physics - Physics Education - Abstract
In response to numerous programs seeking to advance quantum education and workforce development in the United States, experts from academia, industry, government, and professional societies convened for a National Science Foundation-sponsored workshop in February 2024 to explore the benefits and challenges of establishing a national center for quantum education. Broadly, such a center would foster collaboration and build the infrastructure required to develop a diverse and quantum-ready workforce. The workshop discussions centered around how a center could uniquely address gaps in public, K-12, and undergraduate quantum information science and engineering (QISE) education. Specifically, the community identified activities that, through a center, could lead to an increase in student awareness of quantum careers, boost the number of educators trained in quantum-related subjects, strengthen pathways into quantum careers, enhance the understanding of the U.S. quantum workforce, and elevate public engagement with QISE. Core proposed activities for the center include professional development for educators, coordinated curriculum development and curation, expanded access to educational laboratory equipment, robust evaluation and assessment practices, network building, and enhanced public engagement with quantum science.
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- 2024
8. GPT-4o System Card
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OpenAI, Hurst, Aaron, Lerer, Adam, Goucher, Adam P., Perelman, Adam, Ramesh, Aditya, Clark, Aidan, Ostrow, AJ, Welihinda, Akila, Hayes, Alan, Radford, Alec, Mądry, Aleksander, Baker-Whitcomb, Alex, Beutel, Alex, Borzunov, Alex, Carney, Alex, Chow, Alex, Kirillov, Alex, Nichol, Alex, Paino, Alex, Renzin, Alex, Passos, Alex Tachard, Kirillov, Alexander, Christakis, Alexi, Conneau, Alexis, Kamali, Ali, Jabri, Allan, Moyer, Allison, Tam, Allison, Crookes, Amadou, Tootoochian, Amin, Tootoonchian, Amin, Kumar, Ananya, Vallone, Andrea, Karpathy, Andrej, Braunstein, Andrew, Cann, Andrew, Codispoti, Andrew, Galu, Andrew, Kondrich, Andrew, Tulloch, Andrew, Mishchenko, Andrey, Baek, Angela, Jiang, Angela, Pelisse, Antoine, Woodford, Antonia, Gosalia, Anuj, Dhar, Arka, Pantuliano, Ashley, Nayak, Avi, Oliver, Avital, Zoph, Barret, Ghorbani, Behrooz, Leimberger, Ben, Rossen, Ben, Sokolowsky, Ben, Wang, Ben, Zweig, Benjamin, Hoover, Beth, Samic, Blake, McGrew, Bob, Spero, Bobby, Giertler, Bogo, Cheng, Bowen, Lightcap, Brad, Walkin, Brandon, Quinn, Brendan, Guarraci, Brian, Hsu, Brian, Kellogg, Bright, Eastman, Brydon, Lugaresi, Camillo, Wainwright, Carroll, Bassin, Cary, Hudson, Cary, Chu, Casey, Nelson, Chad, Li, Chak, Shern, Chan Jun, Conger, Channing, Barette, Charlotte, Voss, Chelsea, Ding, Chen, Lu, Cheng, Zhang, Chong, Beaumont, Chris, Hallacy, Chris, Koch, Chris, Gibson, Christian, Kim, Christina, Choi, Christine, McLeavey, Christine, Hesse, Christopher, Fischer, Claudia, Winter, Clemens, Czarnecki, Coley, Jarvis, Colin, Wei, Colin, Koumouzelis, Constantin, Sherburn, Dane, Kappler, Daniel, Levin, Daniel, Levy, Daniel, Carr, David, Farhi, David, Mely, David, Robinson, David, Sasaki, David, Jin, Denny, Valladares, Dev, Tsipras, Dimitris, Li, Doug, Nguyen, Duc Phong, Findlay, Duncan, Oiwoh, Edede, Wong, Edmund, Asdar, Ehsan, Proehl, Elizabeth, Yang, Elizabeth, Antonow, Eric, Kramer, Eric, Peterson, Eric, Sigler, Eric, Wallace, Eric, Brevdo, Eugene, Mays, Evan, Khorasani, Farzad, Such, Felipe Petroski, Raso, Filippo, Zhang, Francis, von Lohmann, Fred, Sulit, Freddie, Goh, Gabriel, Oden, Gene, Salmon, Geoff, Starace, Giulio, Brockman, Greg, Salman, Hadi, Bao, Haiming, Hu, Haitang, Wong, Hannah, Wang, Haoyu, Schmidt, Heather, Whitney, Heather, Jun, Heewoo, Kirchner, Hendrik, Pinto, Henrique Ponde de Oliveira, Ren, Hongyu, Chang, Huiwen, Chung, Hyung Won, Kivlichan, Ian, O'Connell, Ian, Osband, Ian, Silber, Ian, Sohl, Ian, Okuyucu, Ibrahim, Lan, Ikai, Kostrikov, Ilya, Sutskever, Ilya, Kanitscheider, Ingmar, Gulrajani, Ishaan, Coxon, Jacob, Menick, Jacob, Pachocki, Jakub, Aung, James, Betker, James, Crooks, James, Lennon, James, Kiros, Jamie, Leike, Jan, Park, Jane, Kwon, Jason, Phang, Jason, Teplitz, Jason, Wei, Jason, Wolfe, Jason, Chen, Jay, Harris, Jeff, Varavva, Jenia, Lee, Jessica Gan, Shieh, Jessica, Lin, Ji, Yu, Jiahui, Weng, Jiayi, Tang, Jie, Yu, Jieqi, Jang, Joanne, Candela, Joaquin Quinonero, Beutler, Joe, Landers, Joe, Parish, Joel, Heidecke, Johannes, Schulman, John, Lachman, Jonathan, McKay, Jonathan, Uesato, Jonathan, Ward, Jonathan, Kim, Jong Wook, Huizinga, Joost, Sitkin, Jordan, Kraaijeveld, Jos, Gross, Josh, Kaplan, Josh, Snyder, Josh, Achiam, Joshua, Jiao, Joy, Lee, Joyce, Zhuang, Juntang, Harriman, Justyn, Fricke, Kai, Hayashi, Kai, Singhal, Karan, Shi, Katy, Karthik, Kavin, Wood, Kayla, Rimbach, Kendra, Hsu, Kenny, Nguyen, Kenny, Gu-Lemberg, Keren, Button, Kevin, Liu, Kevin, Howe, Kiel, Muthukumar, Krithika, Luther, Kyle, Ahmad, Lama, Kai, Larry, Itow, Lauren, Workman, Lauren, Pathak, Leher, Chen, Leo, Jing, Li, Guy, Lia, Fedus, Liam, Zhou, Liang, Mamitsuka, Lien, Weng, Lilian, McCallum, Lindsay, Held, Lindsey, Ouyang, Long, Feuvrier, Louis, Zhang, Lu, Kondraciuk, Lukas, Kaiser, Lukasz, Hewitt, Luke, Metz, Luke, Doshi, Lyric, Aflak, Mada, Simens, Maddie, Boyd, Madelaine, Thompson, Madeleine, Dukhan, Marat, Chen, Mark, Gray, Mark, Hudnall, Mark, Zhang, Marvin, Aljubeh, Marwan, Litwin, Mateusz, Zeng, Matthew, Johnson, Max, Shetty, Maya, Gupta, Mayank, Shah, Meghan, Yatbaz, Mehmet, Yang, Meng Jia, Zhong, Mengchao, Glaese, Mia, Chen, Mianna, Janner, Michael, Lampe, Michael, Petrov, Michael, Wu, Michael, Wang, Michele, Fradin, Michelle, Pokrass, Michelle, Castro, Miguel, de Castro, Miguel Oom Temudo, Pavlov, Mikhail, Brundage, Miles, Wang, Miles, Khan, Minal, Murati, Mira, Bavarian, Mo, Lin, Molly, Yesildal, Murat, Soto, Nacho, Gimelshein, Natalia, Cone, Natalie, Staudacher, Natalie, Summers, Natalie, LaFontaine, Natan, Chowdhury, Neil, Ryder, Nick, Stathas, Nick, Turley, Nick, Tezak, Nik, Felix, Niko, Kudige, Nithanth, Keskar, Nitish, Deutsch, Noah, Bundick, Noel, Puckett, Nora, Nachum, Ofir, Okelola, Ola, Boiko, Oleg, Murk, Oleg, Jaffe, Oliver, Watkins, Olivia, Godement, Olivier, Campbell-Moore, Owen, Chao, Patrick, McMillan, Paul, Belov, Pavel, Su, Peng, Bak, Peter, Bakkum, Peter, Deng, Peter, Dolan, Peter, Hoeschele, Peter, Welinder, Peter, Tillet, Phil, Pronin, Philip, Tillet, Philippe, Dhariwal, Prafulla, Yuan, Qiming, Dias, Rachel, Lim, Rachel, Arora, Rahul, Troll, Rajan, Lin, Randall, Lopes, Rapha Gontijo, Puri, Raul, Miyara, Reah, Leike, Reimar, Gaubert, Renaud, Zamani, Reza, Wang, Ricky, Donnelly, Rob, Honsby, Rob, Smith, Rocky, Sahai, Rohan, Ramchandani, Rohit, Huet, Romain, Carmichael, Rory, Zellers, Rowan, Chen, Roy, Chen, Ruby, Nigmatullin, Ruslan, Cheu, Ryan, Jain, Saachi, Altman, Sam, Schoenholz, Sam, Toizer, Sam, Miserendino, Samuel, Agarwal, Sandhini, Culver, Sara, Ethersmith, Scott, Gray, Scott, Grove, Sean, Metzger, Sean, Hermani, Shamez, Jain, Shantanu, Zhao, Shengjia, Wu, Sherwin, Jomoto, Shino, Wu, Shirong, Shuaiqi, Xia, Phene, Sonia, Papay, Spencer, Narayanan, Srinivas, Coffey, Steve, Lee, Steve, Hall, Stewart, Balaji, Suchir, Broda, Tal, Stramer, Tal, Xu, Tao, Gogineni, Tarun, Christianson, Taya, Sanders, Ted, Patwardhan, Tejal, Cunninghman, Thomas, Degry, Thomas, Dimson, Thomas, Raoux, Thomas, Shadwell, Thomas, Zheng, Tianhao, Underwood, Todd, Markov, Todor, Sherbakov, Toki, Rubin, Tom, Stasi, Tom, Kaftan, Tomer, Heywood, Tristan, Peterson, Troy, Walters, Tyce, Eloundou, Tyna, Qi, Valerie, Moeller, Veit, Monaco, Vinnie, Kuo, Vishal, Fomenko, Vlad, Chang, Wayne, Zheng, Weiyi, Zhou, Wenda, Manassra, Wesam, Sheu, Will, Zaremba, Wojciech, Patil, Yash, Qian, Yilei, Kim, Yongjik, Cheng, Youlong, Zhang, Yu, He, Yuchen, Zhang, Yuchen, Jin, Yujia, Dai, Yunxing, and Malkov, Yury
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Computer Science - Computation and Language ,Computer Science - Artificial Intelligence ,Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Computers and Society ,Computer Science - Machine Learning ,Computer Science - Sound ,Electrical Engineering and Systems Science - Audio and Speech Processing - Abstract
GPT-4o is an autoregressive omni model that accepts as input any combination of text, audio, image, and video, and generates any combination of text, audio, and image outputs. It's trained end-to-end across text, vision, and audio, meaning all inputs and outputs are processed by the same neural network. GPT-4o can respond to audio inputs in as little as 232 milliseconds, with an average of 320 milliseconds, which is similar to human response time in conversation. It matches GPT-4 Turbo performance on text in English and code, with significant improvement on text in non-English languages, while also being much faster and 50\% cheaper in the API. GPT-4o is especially better at vision and audio understanding compared to existing models. In line with our commitment to building AI safely and consistent with our voluntary commitments to the White House, we are sharing the GPT-4o System Card, which includes our Preparedness Framework evaluations. In this System Card, we provide a detailed look at GPT-4o's capabilities, limitations, and safety evaluations across multiple categories, focusing on speech-to-speech while also evaluating text and image capabilities, and measures we've implemented to ensure the model is safe and aligned. We also include third-party assessments on dangerous capabilities, as well as discussion of potential societal impacts of GPT-4o's text and vision capabilities.
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- 2024
9. Synergistic Radiative Transfer Modeling of MgII and Ly{\alpha} Emission in Multiphase, Clumpy Galactic Environments: Application to Low-Redshift Lyman Continuum Leakers
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Li, Zhihui, Gronke, Max, Heckman, Timothy, Xu, Xinfeng, Henry, Alaina, Carr, Cody, Chisholm, John, Borthakur, Sanchayeeta, Marques-Chaves, Rui, Schaerer, Daniel, Leclercq, Floriane, and Berg, Danielle A.
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Astrophysics - Astrophysics of Galaxies - Abstract
We conducted systematic radiative transfer (RT) modeling of the Mg II doublet line profiles for 33 low-redshift Lyman continuum (LyC) leakers, and Ly$\alpha$ modeling for a subset of six objects, using a multiphase, clumpy circumgalactic medium (CGM) model. Our RT models successfully reproduced the Mg II line profiles for all 33 galaxies, revealing a necessary condition for strong LyC leakage: high maximum clump outflow velocity ($v_{\rm MgII,\,max} \gtrsim 390\,\rm km\,s^{-1}$) and low total Mg II column density ($N_{\rm MgII,\,tot} \lesssim 10^{14.3}\,\rm cm^{-2}$). We found that the clump outflow velocity and total Mg II column density have the most significant impact on Mg II spectra and emphasized the need for full RT modeling to accurately extract the CGM gas properties. In addition, using archival HST COS/G160M data, we modeled Ly$\alpha$ profiles for six objects and found that their spectral properties do not fully align with the conventional LyC leakage criteria, yet no clear correlation was identified between the modeled parameters and observed LyC escape fractions. We inferred LyC escape fractions based on HI properties from Ly$\alpha$ RT modeling and found that LyC leakage is primarily governed by the number of optically thick HI clumps per sightline ($f_{\rm cl}$). Intriguingly, two galaxies with relatively low observed LyC leakage exhibited the highest RT-inferred LyC escape fractions due to their lowest $f_{\rm cl}$ values, driven by the strong blue peaks of their Ly$\alpha$ emission. Future high-resolution, spatially resolved observations are crucial for resolving this puzzle. Overall, our results support a "picket fence" geometry over a "density-bounded" scenario for the CGM, where a combination of high Mg II outflow velocities and low Mg II column densities may be correlated with the presence of more low-density HI channels that facilitate LyC escape., Comment: 22 pages, 16 figures, comments are welcome
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- 2024
10. Non-monotonic Extensions to Formal Concept Analysis via Object Preferences
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Carr, Lucas, Leisegang, Nicholas, Meyer, Thomas, and Rudolph, Sebastian
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Computer Science - Logic in Computer Science ,Computer Science - Artificial Intelligence ,I.2.4 - Abstract
Formal Concept Analysis (FCA) is an approach to creating a conceptual hierarchy in which a \textit{concept lattice} is generated from a \textit{formal context}. That is, a triple consisting of a set of objects, $G$, a set of attributes, $M$, and an incidence relation $I$ on $G \times M$. A \textit{concept} is then modelled as a pair consisting of a set of objects (the \textit{extent}), and a set of shared attributes (the \textit{intent}). Implications in FCA describe how one set of attributes follows from another. The semantics of these implications closely resemble that of logical consequence in classical logic. In that sense, it describes a monotonic conditional. The contributions of this paper are two-fold. First, we introduce a non-monotonic conditional between sets of attributes, which assumes a preference over the set of objects. We show that this conditional gives rise to a consequence relation that is consistent with the postulates for non-monotonicty proposed by Kraus, Lehmann, and Magidor (commonly referred to as the KLM postulates). We argue that our contribution establishes a strong characterisation of non-monotonicity in FCA. Typical concepts represent concepts where the intent aligns with expectations from the extent, allowing for an exception-tolerant view of concepts. To this end, we show that the set of all typical concepts is a meet semi-lattice of the original concept lattice. This notion of typical concepts is a further introduction of KLM-style typicality into FCA, and is foundational towards developing an algebraic structure representing a concept lattice of prototypical concepts.
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- 2024
11. Detection of a space capsule entering Earth's atmosphere with distributed acoustic sensing (DAS)
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Carr, Chris G., Donahue, Carly M., Viens, Loic, Beardslee, Luke B., McGhee, Elisa A., and Danielson, Lisa R.
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Earth and Planetary Astrophysics ,Physics - Geophysics - Abstract
On 24 September 2023, the Origins, Spectral Interpretation, Resource Identification, and Security Regolith Explorer (OSIRIS-REx) Sample Return Capsule entered the Earth's atmosphere after successfully collecting samples from an asteroid. The known trajectory and timing of this return provided a rare opportunity to strategically instrument sites to record geophysical signals produced by the capsule as it traveled at hypersonic speeds through the atmosphere. We deployed two optical-fiber distributed acoustic sensing (DAS) interrogators to sample over 12 km of surface-draped, fiber-optic cables along with six co-located seismometer-infrasound sensor pairs, spread across two sites near Eureka, NV. This campaign-style rapid deployment is the first reported recording of a sample return capsule entry with any distributed fiber optic sensing technology. The DAS interrogators recorded an impulsive arrival with an extended coda which had features that were similar to recordings from both the seismometers and infrasound sensors. While the signal-to-noise of the DAS data was lower than the seismic-infrasound data, the extremely dense spacing of fiber-optic sensors allowed for more phases to be clearly distinguished and the continuous transformation of the wavefront as it impacted the ground could be visualized. Unexpectedly, the DAS recordings contain less low-frequency content than is present in both the seismic and infrasound data. The deployment conditions strongly affected the recorded DAS data, in particular, we observed that fiber selection and placement exert strong controls on data quality.
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- 2024
12. Empirical Perturbation Analysis of Linear System Solvers from a Data Poisoning Perspective
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Liu, Yixin, Carr, Arielle, and Sun, Lichao
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Computer Science - Machine Learning ,Computer Science - Cryptography and Security ,Mathematics - Numerical Analysis - Abstract
The perturbation analysis of linear solvers applied to systems arising broadly in machine learning settings -- for instance, when using linear regression models -- establishes an important perspective when reframing these analyses through the lens of a data poisoning attack. By analyzing solvers' responses to such attacks, this work aims to contribute to the development of more robust linear solvers and provide insights into poisoning attacks on linear solvers. In particular, we investigate how the errors in the input data will affect the fitting error and accuracy of the solution from a linear system-solving algorithm under perturbations common in adversarial attacks. We propose data perturbation through two distinct knowledge levels, developing a poisoning optimization and studying two methods of perturbation: Label-guided Perturbation (LP) and Unconditioning Perturbation (UP). Existing works mainly focus on deriving the worst-case perturbation bound from a theoretical perspective, and the analysis is often limited to specific kinds of linear system solvers. Under the circumstance that the data is intentionally perturbed -- as is the case with data poisoning -- we seek to understand how different kinds of solvers react to these perturbations, identifying those algorithms most impacted by different types of adversarial attacks., Comment: 18 pages
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- 2024
13. Analysing Disability Descriptions and Student Suggestions as a Foundation to Overcome Barriers to Learning
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Tim Coughlan, Francisco Iniesto, and Jessica E. Carr
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Artificial intelligence can support increasingly complex conversational interactions and also has the potential to interpret meanings from free text input and make recommendations based on patterns in data. There are important opportunities to apply this to real-world problems faced in access to education. In this paper, we summarise existing research and trends linking disability support and technology, then report on a survey conducted with students with disclosed disabilities (n = 138) to explore what systems might need to do to effectively understand disabled students in their own words, and provide suggestions of technologies, strategies and resources that could be relevant to overcoming barriers to learning. Through thematic analysis, five approaches that students used to talk about their disabilities are identified(medical, functional, support, experiential and administrative), and three major types of suggestions they make around what supported them and may be useful to others are also identified (external tools, university support and practices, concerns and solutions). The survey approach and the findings of the analysis provide a potential foundation for the effective design of systems that could crowdsource a knowledgebase around disabilities, hold conversations to understand disabilities and barriers and make relevant recommendations to individuals as to how they could overcome these barriers.
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- 2024
14. The Influence of Affirmative Action Bans on Institutional Retention
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Xiaodan Hu, Kubra Say, Jeanette Barker, and Brennan Carr
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With its direct impact on admissions procedures and (in)direct impact on campus climate, affirmative action bans can potentially influence student retention. This study uses a national dataset to examine the relationship between affirmative action bans in Oklahoma and New Hampshire and retention rates at public colleges and universities. Our findings indicate that the adoption of affirmative action bans is not associated with the average full-time or part-time retention rates for treated institutions relative to those institutions without affirmative action bans. We discuss the implications with respect to admissions policy changes, students' college choices, and alternative policies to increase student diversity, equity, and inclusion.
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- 2024
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15. Work Education and Educational Developments around Sustainable Livelihoods for Sustainable Career Development and Well-Being
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J. F. Caringal-Go, S. C. Carr, D. J. Hodgetts, D. Y. Intraprasert, M. Maleka, I. McWha-Hermann, I. Meyer, K. P. Mohan, M. H. Nguyen, S. Noklang, V. T. Pham, P. Prakongpan, P. Poonpol, J. Potgieter, R. Searle, and M. Teng-Calleja
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COVID-19, Artificial Intelligence (AI), and Climate Change, have disrupted work education, rendering sustainability of careers and livelihoods a concern. This paper outlines a collaborative response to that challenge, offering opportunities for sustainable livelihoods in a work education cloud collaboration, Project SLiC (Sustainable Livelihoods Collaboration). We have joined forces across nation states in the Global South/North to share cloud resources, focused on teaching a postgraduate course, Sustainable Livelihoods. Online modules are stored in a secure cloud site, from which local courses draw-down, autochthonously, whichever resources fit workforce development in context. We outline modules, and an evaluative process, in a proof-of-concept trial. Finally, we envisage how this initial collaboration may morph into a whole degree, including research supervision. We close with a call to career development professionals to share their unique expertise and experiences at the work education frontline, on how to develop this sustainable careers project, for the greater good.
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- 2024
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16. Sustainable Careers within Greening Economies
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Veronica Hopner, Stuart C. Carr, and Julia Wloch
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Sustainable Livelihoods are more adaptable than precarious jobs, for career development through Decent Work. An essential element for Career Sustainability is Climate action, that includes Just Transitions from carbon-intensive to carbon-neutral or regenerative work. This paper analyses a municipal transition from coal-mining to a more carbon-neutral, city economy, which has foregrounded just transition for miners, and improved the wider ecosystem. The Polish city of Katowice in Poland illustrates how work and career structures, in this case municipal, can work for people in everyday life and their future careers. The case may also serve as a lighthouse project for future just transitions, as part of sustainable career development, by greening economies and supporting access to decent work for all.
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- 2024
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17. A (sub)field guide to quality control in hippocampal subfield segmentation on high‐resolution T2‐weighted MRI
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Canada, Kelsey L, Mazloum‐Farzaghi, Negar, Rådman, Gustaf, Adams, Jenna N, Bakker, Arnold, Baumeister, Hannah, Berron, David, Bocchetta, Martina, Carr, Valerie A, Dalton, Marshall A, de Flores, Robin, Keresztes, Attila, La Joie, Renaud, Mueller, Susanne G, Raz, Naftali, Santini, Tales, Shaw, Thomas, Stark, Craig EL, Tran, Tammy T, Wang, Lei, Wisse, Laura EM, Wuestefeld, Anika, Yushkevich, Paul A, Olsen, Rosanna K, Daugherty, Ana M, and Group, the Hippocampal Subfields
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Biological Psychology ,Cognitive and Computational Psychology ,Psychology ,Neurosciences ,Bioengineering ,Biomedical Imaging ,Hippocampus ,Humans ,Magnetic Resonance Imaging ,Quality Control ,Image Processing ,Computer-Assisted ,Reproducibility of Results ,Neuroimaging ,Hippocampal Subfields Group ,MRI ,best practices ,hippocampal subfields ,quality control ,segmentation ,Cognitive Sciences ,Experimental Psychology ,Biological psychology ,Cognitive and computational psychology - Abstract
Inquiries into properties of brain structure and function have progressed due to developments in magnetic resonance imaging (MRI). To sustain progress in investigating and quantifying neuroanatomical details in vivo, the reliability and validity of brain measurements are paramount. Quality control (QC) is a set of procedures for mitigating errors and ensuring the validity and reliability of brain measurements. Despite its importance, there is little guidance on best QC practices and reporting procedures. The study of hippocampal subfields in vivo is a critical case for QC because of their small size, inter-dependent boundary definitions, and common artifacts in the MRI data used for subfield measurements. We addressed this gap by surveying the broader scientific community studying hippocampal subfields on their views and approaches to QC. We received responses from 37 investigators spanning 10 countries, covering different career stages, and studying both healthy and pathological development and aging. In this sample, 81% of researchers considered QC to be very important or important, and 19% viewed it as fairly important. Despite this, only 46% of researchers reported on their QC processes in prior publications. In many instances, lack of reporting appeared due to ambiguous guidance on relevant details and guidance for reporting, rather than absence of QC. Here, we provide recommendations for correcting errors to maximize reliability and minimize bias. We also summarize threats to segmentation accuracy, review common QC methods, and make recommendations for best practices and reporting in publications. Implementing the recommended QC practices will collectively improve inferences to the larger population, as well as have implications for clinical practice and public health.
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- 2024
18. Risk-stratified treatment for drug-susceptible pulmonary tuberculosis
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Chang, Vincent K, Imperial, Marjorie Z, Phillips, Patrick PJ, Velásquez, Gustavo E, Nahid, Payam, Vernon, Andrew, Kurbatova, Ekaterina V, Swindells, Susan, Chaisson, Richard E, Dorman, Susan E, Johnson, John L, Weiner, Marc, Sizemore, Erin E, Whitworth, William, Carr, Wendy, Bryant, Kia E, Burton, Deron, Dooley, Kelly E, Engle, Melissa, Nsubuga, Pheona, Diacon, Andreas H, Nhung, Nguyen Viet, Dawson, Rodney, and Savic, Radojka M
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Biomedical and Clinical Sciences ,Clinical Sciences ,Clinical Research ,Lung ,Clinical Trials and Supportive Activities ,Prevention ,Infectious Diseases ,Patient Safety ,Tuberculosis ,Emerging Infectious Diseases ,Orphan Drug ,Rare Diseases ,6.1 Pharmaceuticals ,Infection ,Good Health and Well Being ,Humans ,Rifampin ,Tuberculosis ,Pulmonary ,Male ,Female ,Adult ,Middle Aged ,Antitubercular Agents ,Moxifloxacin ,Risk Factors ,Treatment Outcome ,Mycobacterium tuberculosis ,Drug Therapy ,Combination ,Young Adult ,AIDS Clinical Trial Group ,Tuberculosis Trials Consortium - Abstract
The Phase 3 randomized controlled trial, TBTC Study 31/ACTG A5349 (NCT02410772) demonstrated that a 4-month rifapentine-moxifloxacin regimen for drug-susceptible pulmonary tuberculosis was safe and effective. The primary efficacy outcome was 12-month tuberculosis disease free survival, while the primary safety outcome was the proportion of grade 3 or higher adverse events during the treatment period. We conducted an analysis of demographic, clinical, microbiologic, radiographic, and pharmacokinetic data and identified risk factors for unfavorable outcomes and adverse events. Among participants receiving the rifapentine-moxifloxacin regimen, low rifapentine exposure is the strongest driver of tuberculosis-related unfavorable outcomes (HR 0.65 for every 100 µg∙h/mL increase, 95%CI 0.54-0.77). The only other risk factors identified are markers of higher baseline disease severity, namely Xpert MTB/RIF cycle threshold and extent of disease on baseline chest radiography (Xpert: HR 1.43 for every 3-cycle-threshold decrease, 95%CI 1.07-1.91; extensive disease: HR 2.02, 95%CI 1.07-3.82). From these risk factors, we developed a simple risk stratification to classify disease phenotypes as easier-, moderately-harder, or harder-to-treat TB. Notably, high rifapentine exposures are not associated with any predefined adverse safety outcomes. Our results suggest that the easier-to-treat subgroup may be eligible for further treatment shortening while the harder-to-treat subgroup may need higher doses or longer treatment.
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- 2024
19. Shining a Light on the Connections between Galactic Outflows Seen in Absorption and Emission Lines
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Xu, Xinfeng, Henry, Alaina, Heckman, Timothy, Carr, Cody, Strom, Allison L., Jones, Tucker, Berg, Danielle A., Chisholm, John, Erb, Dawn, James, Bethan L., Jaskot, Anne, Martin, Crystal L., Mingozzi, Matilde, Senchyna, Peter, Roy, Namrata, Scarlata, Claudia, and Stark, Daniel P.
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Astrophysics - Astrophysics of Galaxies - Abstract
Galactic outflows provide important feedback effects to regulate the evolution of the host galaxies. Two primary diagnostics of galactic outflows are broad and/or blueshifted emission and absorption lines. Even though well-established methods exist to analyze these outflow signatures, connections between them are rarely studied and largely unknown. In this paper, we present the first detailed comparisons of the outflow properties measured independently from the two outflow diagnostics for a sample of 33 low-redshift star-forming galaxies. Their UV absorption lines are detected by the Hubble Space Telescope/Cosmic Origin Spectrograph, and optical emission lines are observed by the Keck/Echellette Spectrograph and Imager. We find that several outflow properties derived from emission and absorption lines are tightly correlated. These include outflow maximum velocity, line width, and sizes. Specifically, in a given galaxy, outflows seen in emission lines have smaller maximum velocities, narrower line widths, and smaller sizes than those measured from the absorption lines. These findings can be interpreted by the fact that emission line luminosity is weighted by density squared, while absorption line depth is weighted by density. We then test both spherical and bi-conical outflow models, and find the same outflow velocity and density distributions can explain the observed outflow features in emission and absorption lines for individual galaxies. These results provide novel calibration between galactic outflow properties measured from the two diagnostics and provide valuable insights for future models of galactic outflows by potentially doubling the number of observational constraints., Comment: 3 tables, 17 figures, 30 pages, submitted to ApJ
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- 2024
20. Water in protoplanetary disks with JWST-MIRI: spectral excitation atlas and radial distribution from temperature diagnostic diagrams and Doppler mapping
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Banzatti, Andrea, Salyk, Colette, Pontoppidan, Klaus M., Carr, John, Zhang, Ke, Arulanantham, Nicole, Krijt, Sebastiaan, Oberg, Karin I., Cleeves, L. Ilsedore, Najita, Joan, Pascucci, Ilaria, Blake, Geoffrey A., Romero-Mirza, Carlos E., Bergin, Edwin A., Cieza, Lucas A., Pinilla, Paola, Long, Feng, Mallaney, Patrick, Xie, Chengyan, Waggoner, Abygail R., Kaeufer, Till, and collaboration, the JDISCS
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
This work aims at providing fundamental general tools for the analysis of water spectra as observed in protoplanetary disks with JWST-MIRI. We analyze 25 high-quality spectra from the JDISC Survey reduced with asteroid calibrators as presented in Pontoppidan et al. (2024). First, we present a spectral atlas to illustrate the clustering of H$_2$O transitions from different upper level energies ($E_u$) and identify single (un-blended) transitions that provide the most reliable measurements. With that, we demonstrate two important excitation effects: the opacity saturation of ortho-para line pairs that overlap, and the non-LTE excitation of $v=1-1$ lines scattered across the $v=0-0$ rotational band. Second, we define a shorter list of fundamental lines spanning $E_u=$ 1500-6000 K to develop simple line-ratio diagnostic diagrams for the radial temperature distribution of water in inner disks, which can be interpreted using discrete temperature components or a radial gradient. Third, we report the detection of disk-rotation Doppler broadening of molecular lines, which confirms the radial distribution of water emission including, for the first time, the radially-extended $\approx$ 170-220 K reservoir close to the snowline. The combination of measured line ratios and broadening suggests that drift-dominated disks have shallower temperature gradients with an extended cooler disk surface enriched by ice sublimation. We also report the first detection of a H$_2$O-rich inner disk wind from narrow blue-shifted absorption in the ro-vibrational lines. We summarize these findings and tools into a general recipe to make the study of water in planet-forming regions reliable, effective, and sustainable for samples of $> 100$ disks., Comment: Accepted for publication in The Astronomical Journal
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- 2024
21. The Low-Redshift Lyman Continuum Survey: The Roles of Stellar Feedback and ISM Geometry in LyC Escape
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Flury, Sophia R., Jaskot, Anne E., Saldana-Lopez, Alberto, Oey, M. S., Chisholm, John, Amorín, Ricardo, Bait, Omkar, Borthakur, Sanchayeeta, Carr, Cody, Ferguson, Henry C., Giavalisco, Mauro, Hayes, Matthew, Heckman, Timothy, Henry, Alaina, Ji, Zhiyuan, Komarova, Lena, Leclercq, Floriane, Reste, Alexandra Le, McCandliss, Stephan, Marques-Chaves, Rui, Östlin, Göran, Pentericci, Laura, Ravindranath, Swara, Rutkowski, Michael, Scarlata, Claudia, Schaerer, Daniel, Thuan, Trinh, Trebitsch, Maxime, Vanzella, Eros, Verhamme, Anne, Wang, Bingjie, Worseck, Gábor, and Xu, Xinfeng
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
One of the fundamental questions of cosmology is the origin and mechanism(s) responsible for the reionization of the Universe beyond $z\sim6$. To address this question, many studies over the past decade have focused on local ($z\sim0.3$) galaxies which leak ionizing radiation (Lyman continuum or LyC). However, line-of-sight effects and data quality have prohibited deeper insight into the nature of LyC escape. To circumvent these limitations, we analyze stacks of a consolidated sample of {\it HST}/COS observations of the LyC in 89 galaxies at $z\sim0.3$. From fitting of the continuum, we obtain information about the underlying stellar populations and neutral ISM geometry. We find that most LyC non-detections are not leaking appreciable LyC ($f_{esc}^{\rm LyC}<1$\%) but also that exceptional cases point to spatial variations in the LyC escape fraction $f_{esc}^{\rm LyC}$. Stellar populations younger than 3 Myr lead to an increase in ionizing feedback, which in turn increases the isotropy of LyC escape. Moreover, mechanical feedback from supernovae in 8-10 Myr stellar populations is important for anisotropic gas distributions needed for LyC escape. While mechanical feedback is necessary for any LyC escape, high $f_{esc}^{\rm LyC}$ ($>5$\%) also requires a confluence of young stars and ionizing feedback. A two-stage burst of star formation could facilitate this optimal LyC escape scenario., Comment: Submitted to AAS publications, 42 pages, 25 figures
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- 2024
22. A Dynamic Weighting Strategy to Mitigate Worker Node Failure in Distributed Deep Learning
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Xu, Yuesheng and Carr, Arielle
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Computer Science - Machine Learning ,Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
The increasing complexity of deep learning models and the demand for processing vast amounts of data make the utilization of large-scale distributed systems for efficient training essential. These systems, however, face significant challenges such as communication overhead, hardware limitations, and node failure. This paper investigates various optimization techniques in distributed deep learning, including Elastic Averaging SGD (EASGD) and the second-order method AdaHessian. We propose a dynamic weighting strategy to mitigate the problem of straggler nodes due to failure, enhancing the performance and efficiency of the overall training process. We conduct experiments with different numbers of workers and communication periods to demonstrate improved convergence rates and test performance using our strategy.
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- 2024
23. Stochastic models of advection-diffusion in layered media
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Carr, Elliot J.
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Physics - Computational Physics - Abstract
Mathematically modelling diffusive and advective transport of particles in heterogeneous layered media is important to many applications in computational, biological and medical physics. While deterministic continuum models of such transport processes are well established, they fail to account for randomness inherent in many problems and are valid only for a large number of particles. To address this, this paper derives a suite of equivalent stochastic (discrete-time discrete-space random walk) models for several standard continuum (partial differential equation) models of diffusion and advection-diffusion across a fully- or semi-permeable interface. Our approach involves discretising the continuum model in space and time to yield a Markov chain, which governs the transition probabilities between spatial lattice sites during each time step. Discretisation in space is carried out using a standard finite volume method while two options are considered for discretisation in time. A simple forward Euler discretisation yields a stochastic model taking the form of a local (nearest-neighbour) random walk with simple analytical expressions for the transition probabilities while an exact exponential discretisation yields a non-local random walk with transition probabilities defined numerically via a matrix exponential. Constraints on the size of the spatial and/or temporal steps are provided for each option to ensure the transition probabilities are non-negative. MATLAB code comparing the stochastic and continuum models is available on GitHub (https://github.com/elliotcarr/Carr2024c) with simulation results demonstrating good agreement for several example problems., Comment: 17 pages, 3 figures
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- 2024
24. Deep Learning for Koopman Operator Estimation in Idealized Atmospheric Dynamics
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Millard, David, Carr, Arielle, and Gaudreault, Stéphane
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Computer Science - Machine Learning ,Mathematics - Dynamical Systems ,Physics - Atmospheric and Oceanic Physics - Abstract
Deep learning is revolutionizing weather forecasting, with new data-driven models achieving accuracy on par with operational physical models for medium-term predictions. However, these models often lack interpretability, making their underlying dynamics difficult to understand and explain. This paper proposes methodologies to estimate the Koopman operator, providing a linear representation of complex nonlinear dynamics to enhance the transparency of data-driven models. Despite its potential, applying the Koopman operator to large-scale problems, such as atmospheric modeling, remains challenging. This study aims to identify the limitations of existing methods, refine these models to overcome various bottlenecks, and introduce novel convolutional neural network architectures that capture simplified dynamics.
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- 2024
25. The Effect of Radiation and Supernovae Feedback on LyC Escape in Local Star-forming Galaxies
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Carr, Cody A., Cen, Renyue, Scarlata, Claudia, Xu, Xinfeng, Henry, Alaina, Marques-Chaves, Rui, Schaerer, Daniel, Amorín, Ricardo O., Oey, M. S., Komarova, Lena, Flury, Sophia, Jaskot, Anne, Saldana-Lopez, Alberto, Ji, Zhiyuan, Huberty, Mason, Heckman, Timothy, Ostlin, Göran, Bait, Omkar, Hayes, Matthew James, Thuan, Trinh, Berg, Danielle A., Giavalisco, Mauro, Borthakur, Sanchayeeta, Chisholm, John, Ferguson, Harry C., Michel-Dansac, Leo, Verhamme, Anne, and Worseck, Gábor
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Astrophysics - Astrophysics of Galaxies - Abstract
Feedback is widely recognized as an essential condition for Lyman continuum (LyC) escape in star-forming galaxies. However, the mechanisms by which galactic outflows clear neutral gas and dust remain unclear. In this paper, we model the Mg II 2796\r{A}, 2804\r{A} absorption + emission lines in 29 galaxies taken from the Low-z LyC Survey (LzLCS) to investigate the impact of (radiation + mechanical) feedback on LyC escape. Using constraints on Mg$^+$ and photoionization models, we map the outflows' neutral hydrogen content and predict $f_{esc}^{LyC}$ with a multiphase wind model. We measure mass, momentum, and energy loading factors for the neutral winds, which carry up to 10% of the momentum and 1% of the energy in SFR-based deposition rates. We use SED template fitting to determine the relative ages of stellar populations, allowing us to identify radiation feedback dominant systems. We then examine feedback related properties (stellar age, loading factors, etc.) under conditions that optimize feedback efficiency, specifically high star formation rate surface density and compact UV half-light radii. Our findings indicate that the strongest leakers are radiation feedback dominant, lack Mg II outflows, but have extended broad components in higher ionization lines like [O III] 5007\r{A}, as observed by Amor\'in et al. (2024). In contrast, galaxies experiencing supernovae feedback typically exhibit weaker $f_{esc}^{LyC}$ and show evidence of outflows in both Mg II and higher ionization lines. We attribute these findings to rapid or "catastrophic" cooling in the radiation-dominant systems, which, given the low metallicities in our sample, are likely experiencing delayed supernovae., Comment: 34 pages, 16 figures, 7 tables
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- 2024
26. Bayesian Inference General Procedures for A Single-subject Test Study
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Li, Jie, Green, Gary, Carr, Sarah J. A., Liu, Peng, and Zhang, Jian
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Statistics - Applications - Abstract
Abnormality detection in the identification of a single-subject which deviates from the majority of the dataset that comes from a control group is a critical problem. A common approach is to assume that the control group can be characterised in terms of standard Normal statistics and the detection of single abnormal subject is in that context. But in many situations the control group can not be described in terms of Normal statistics and the use of standard statistics is inappropriate. This paper presents a Bayesian Inference General Procedures for A Single-Subject Test (BIGPAST), designed to mitigate the effects of skewness under the assumption that the dataset of control group comes from the skewed Student's \( t \) distribution. BIGPAST operates under the null hypothesis that the single-subject follows the same distribution as the control group. We assess BIGPAST's performance against other methods through a series of simulation studies. The results demonstrate that BIGPAST is robust against deviations from normality and outperforms the existing approaches in terms of accuracy. This is because BIGPAST can effectively reduce model misspecification errors under the skewed Student's \( t \) assumption. We apply BIGPAST to a MEG dataset consisting of an individual with mild traumatic brain injury and an age and gender-matched control group, demonstrating its effectiveness in detecting abnormalities in the single-subject., Comment: 35 pages, 12 figures and 10 tables
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- 2024
27. The Impact from Galaxy Groups on Cosmological Measurements with Type Ia Supernovae
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Peterson, Erik R., Carreres, Bastien, Carr, Anthony, Scolnic, Daniel, Bailey, Ava, Davis, Tamara M., Brout, Dillon, Howlett, Cullan, Jones, David O., Riess, Adam G., Said, Khaled, and Taylor, Georgie
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
At the low-redshift end ($z<0.05$) of the Hubble diagram with Type Ia Supernovae (SNe Ia), the contribution to Hubble residual scatter from peculiar velocities is of similar size to that due to the standardization of the SN Ia light curve. A way to improve the redshift measurement of the SN host galaxy is to utilize the average redshift of the galaxy group, effectively averaging over small-scale/intracluster peculiar velocities. One limiting factor is the fraction of SN host galaxies in galaxy groups, previously found to be 30% using (relatively incomplete) magnitude-limited galaxy catalogs. Here, we do the first analysis of N-body simulations to predict this fraction, finding $\sim$66% should have associated groups and group averaging should improve redshift precision by $\sim$120 km s$^{-1}$. Furthermore, using spectroscopic data from the Anglo-Australian Telescope, we present results from the first pilot program to evaluate whether or not 23 previously unassociated SN Ia hosts belong in groups. We find that 91% of these candidates can be associated with groups, consistent with predictions from simulations given the sample size. Combining with previously assigned SN host galaxies in Pantheon+, we demonstrate improvement in Hubble residual scatter equivalent to 145 km s$^{-1}$, also consistent with simulations. For new and upcoming low-$z$ samples from, for example, the Zwicky Transient Facility and the Rubin Observatory's Legacy Survey of Space and Time, a separate follow-up program identifying galaxy groups of SN hosts is a highly cost-effective way to enhance their constraining power., Comment: 17 pages, 12 figures. Submitted to ApJ
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- 2024
28. JWST Validates HST Distance Measurements: Selection of Supernova Subsample Explains Differences in JWST Estimates of Local H0
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Riess, Adam G., Scolnic, Dan, Anand, Gagandeep S., Breuval, Louise, Casertano, Stefano, Macri, Lucas M., Li, Siyang, Yuan, Wenlong, Huang, Caroline D., Jha, Saurabh, Murakami, Yukei S., Beaton, Rachael, Brout, Dillon, Wu, Tianrui, Addison, Graeme E., Bennett, Charles, Anderson, Richard I., Filippenko, Alexei V., and Carr, Anthony
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
JWST provides new opportunities to cross-check the HST Cepheid/SNeIa distance ladder, which yields the most precise local measure of H0. We analyze early JWST subsamples (~1/4 of the HST sample) from the SH0ES and CCHP groups, calibrated by a single anchor (N4258). We find HST Cepheid distances agree well (~1 sigma) with all 8 combinations of methods, samples, and telescopes: JWST Cepheids, TRGB, and JAGB by either group, plus HST TRGB and Miras. The comparisons explicitly include the measurement uncertainty of each method in N4258, an oft-neglected but dominant term. Mean differences are ~0.03 mag, far smaller than the 0.18 mag "Hubble tension." Combining all measures produces the strongest constraint yet on the linearity of HST Cepheid distances, 0.994+-0.010, ruling out distance-dependent bias or offset as the source of the tension at ~7 sigma. Yet, measurements of H0 from current JWST subsamples produce large sampling differences whose size and direction we can directly estimate from the full HST set. We show that Delta(H0)~2.5 km/s/Mpc between the CCHP JWST program and the full HST sample is entirely consistent with differences in sample selection. Combining all JWST samples produces a new, distance-limited set of 16 SNeIa at D<25 Mpc and more closely resembles the full sample thanks to "reversion to the mean" of larger samples. Using JWST Cepheids, JAGB, and TRGB, we find 73.4+-2.1, 72.2+-2.2, and 72.1+-2.2 km/s/Mpc, respectively. Explicitly accounting for SNe in common, the combined-sample three-method result from JWST is H0=72.6+-2.0, similar to H0=72.8 expected from HST Cepheids in the same galaxies. The small JWST sample trivially lowers the Hubble tension significance due to small-sample statistics and is not yet competitive with the HST set (42 SNeIa and 4 anchors), which yields 73.2+-0.9. Still, the joint JWST sample provides important crosschecks which the HST data passes., Comment: ApJ accepted, version replaced with accepted version
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- 2024
29. The All-Sky Impact of the LMC on the Milky Way Circumgalactic Medium
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Carr, Christopher, Bryan, Greg L., Garavito-Camargo, Nicolás, Besla, Gurtina, Setton, David J., and Johnston, Kathryn V.
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Astrophysics - Astrophysics of Galaxies - Abstract
The first infall of the LMC into the Milky Way (MW) represents a large and recent disruption to the MW circumgalactic medium (CGM). In this work, we use idealized, hydrodynamical simulations of a MW-like CGM embedded in a live dark matter halo with an infalling LMC-like satellite initialized with its own CGM to understand how the encounter is shaping the global physical and kinematic properties of the MW CGM. First, we find that the LMC sources order-unity enhancements in MW CGM density, temperature, and pressure from a $\mathcal{M} \approx 2$ shock from the supersonic CGM-CGM collision, extending from the LMC to beyond $\sim R_{\rm 200, MW}$, enhancing column densities, X-ray brightness, the thermal Sunyaev-Zeldovich (tSZ) distortion, and potentially synchrotron emission from cosmic rays over large angular scales across the Southern Hemisphere. Second, the MW's reflex motion relative to its outer halo produces a dipole in CGM radial velocities, with $v_{\rm R} \pm 30-50$ km/s at $R > 50$ kpc in the Northern/Southern hemispheres respectively, consistent with measurements in the stellar halo. Finally, ram pressure strips most of the LMC CGM gas by the present day, leaving $\sim 10^{8-9} M_{\odot}$ of warm, ionized gas along the past orbit of the LMC moving at high radial and/or tangential velocities $\sim 50-100$ kpc from the MW. Massive satellites like the LMC leave their mark on the CGM structure of their host galaxies, and signatures from this interaction may manifest in key all-sky observables of the CGM of the MW and other massive galaxies., Comment: Submitted to ApJ. 22 pages, 15 Figures. Comments welcomed
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- 2024
30. Pessimistic Iterative Planning for Robust POMDPs
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Galesloot, Maris F. L., Suilen, Marnix, Simão, Thiago D., Carr, Steven, Spaan, Matthijs T. J., Topcu, Ufuk, and Jansen, Nils
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Computer Science - Artificial Intelligence ,Computer Science - Machine Learning - Abstract
Robust POMDPs extend classical POMDPs to handle model uncertainty. Specifically, robust POMDPs exhibit so-called uncertainty sets on the transition and observation models, effectively defining ranges of probabilities. Policies for robust POMDPs must be (1) memory-based to account for partial observability and (2) robust against model uncertainty to account for the worst-case instances from the uncertainty sets. To compute such robust memory-based policies, we propose the pessimistic iterative planning (PIP) framework, which alternates between two main steps: (1) selecting a pessimistic (non-robust) POMDP via worst-case probability instances from the uncertainty sets; and (2) computing a finite-state controller (FSC) for this pessimistic POMDP. We evaluate the performance of this FSC on the original robust POMDP and use this evaluation in step (1) to select the next pessimistic POMDP. Within PIP, we propose the rFSCNet algorithm. In each iteration, rFSCNet finds an FSC through a recurrent neural network by using supervision policies optimized for the pessimistic POMDP. The empirical evaluation in four benchmark environments showcases improved robustness against several baseline methods and competitive performance compared to a state-of-the-art robust POMDP solver.
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- 2024
31. Iterative quantum optimization of spin glass problems with rapidly oscillating transverse fields
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Barton, Brandon, Sagal, Jacob, Feeney, Sean, Grattan, George, Patnaik, Pratik, Oganesyan, Vadim, Carr, Lincoln D, and Kapit, Eliot
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Quantum Physics - Abstract
In this work, we introduce a new iterative quantum algorithm, called Iterative Symphonic Tunneling for Satisfiability problems (IST-SAT), which solves quantum spin glass optimization problems using high-frequency oscillating transverse fields. IST-SAT operates as a sequence of iterations, in which bitstrings returned from one iteration are used to set spin-dependent phases in oscillating transverse fields in the next iteration. Over several iterations, the novel mechanism of the algorithm steers the system toward the problem ground state. We benchmark IST-SAT on sets of hard MAX-3-XORSAT problem instances with exact state vector simulation, and report polynomial speedups over trotterized adiabatic quantum computation (TAQC) and the best known semi-greedy classical algorithm. When IST-SAT is seeded with a sufficiently good initial approximation, the algorithm converges to exact solution(s) in a polynomial number of iterations. Our numerical results identify a critial Hamming radius(CHR), or quality of initial approximation, where the time-to-solution crosses from exponential to polynomial scaling in problem size. By combining IST-SAT with future classical or quantum approximation algorithms, larger gains may be achieved. The mechanism we present in this work thus presents a new path toward achieving quantum advantage in optimization.
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- 2024
32. Distributed Augmentation, Hypersweeps, and Branch Decomposition of Contour Trees for Scientific Exploration
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Li, Mingzhe, Carr, Hamish, Rübel, Oliver, Wang, Bei, and Weber, Gunther H.
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Computer Science - Computational Geometry ,Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
Contour trees describe the topology of level sets in scalar fields and are widely used in topological data analysis and visualization. A main challenge of utilizing contour trees for large-scale scientific data is their computation at scale using high-performance computing. To address this challenge, recent work has introduced distributed hierarchical contour trees for distributed computation and storage of contour trees. However, effective use of these distributed structures in analysis and visualization requires subsequent computation of geometric properties and branch decomposition to support contour extraction and exploration. In this work, we introduce distributed algorithms for augmentation, hypersweeps, and branch decomposition that enable parallel computation of geometric properties, and support the use of distributed contour trees as query structures for scientific exploration. We evaluate the parallel performance of these algorithms and apply them to identify and extract important contours for scientific visualization., Comment: 9 pages, accepted by IEEE VIS 2024
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- 2024
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33. Adaptive planning for risk-aware predictive digital twins
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Tezzele, Marco, Carr, Steven, Topcu, Ufuk, and Willcox, Karen E.
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Mathematics - Numerical Analysis - Abstract
This work proposes a mathematical framework to increase the robustness to rare events of digital twins modelled with graphical models. We incorporate probabilistic model-checking and linear programming into a dynamic Bayesian network to enable the construction of risk-averse digital twins. By modeling with a random variable the probability of the asset to transition from one state to another, we define a parametric Markov decision process. By solving this Markov decision process, we compute a policy that defines state-dependent optimal actions to take. To account for rare events connected to failures we leverage risk measures associated with the distribution of the random variables describing the transition probabilities. We refine the optimal policy at every time step resulting in a better trade off between operational costs and performances. We showcase the capabilities of the proposed framework with a structural digital twin of an unmanned aerial vehicle and its adaptive mission replanning.
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- 2024
34. Stable Audio Open
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Evans, Zach, Parker, Julian D., Carr, CJ, Zukowski, Zack, Taylor, Josiah, and Pons, Jordi
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Computer Science - Sound ,Computer Science - Artificial Intelligence ,Electrical Engineering and Systems Science - Audio and Speech Processing - Abstract
Open generative models are vitally important for the community, allowing for fine-tunes and serving as baselines when presenting new models. However, most current text-to-audio models are private and not accessible for artists and researchers to build upon. Here we describe the architecture and training process of a new open-weights text-to-audio model trained with Creative Commons data. Our evaluation shows that the model's performance is competitive with the state-of-the-art across various metrics. Notably, the reported FDopenl3 results (measuring the realism of the generations) showcase its potential for high-quality stereo sound synthesis at 44.1kHz., Comment: Demo: https://stability-ai.github.io/stable-audio-open-demo/ Weights: https://huggingface.co/stabilityai/stable-audio-open-1.0 Code: https://github.com/Stability-AI/stable-audio-tools. arXiv admin note: text overlap with arXiv:2404.10301
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- 2024
35. Geophysical Observations of the 24 September 2023 OSIRIS-REx Sample Return Capsule Re-Entry
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Silber, Elizabeth A., Bowman, Daniel C., Carr, Chris G., Eisenberg, David P., Elbing, Brian R., Fernando, Benjamin, Garcés, Milton A., Haaser, Robert, Krishnamoorthy, Siddharth, Langston, Charles A., Nishikawa, Yasuhiro, Webster, Jeremy, Anderson, Jacob F., Arrowsmith, Stephen, Bazargan, Sonia, Beardslee, Luke, Beck, Brant, Bishop, Jordan W., Blom, Philip, Bracht, Grant, Chichester, David L., Christe, Anthony, Clarke, Jacob, Cummins, Kenneth, Cutts, James, Danielson, Lisa, Donahue, Carly, Eack, Kenneth, Fleigle, Michael, Fox, Douglas, Goel, Ashish, Green, David, Hasumi, Yuta, Hayward, Chris, Hicks, Dan, Hix, Jay, Horton, Stephen, Hough, Emalee, Huber, David P., Hunt, Madeline A., Inman, Jennifer, Islam, S. M. Ariful, Izraelevitz, Jacob, Jacob, Jamey D., Johnson, James, KC, Real J., Komjathy, Attila, Lam, Eric, LaPierre, Justin, Lewis, Kevin, Lewis, Richard D., Liu, Patrick, Martire, Léo, McCleary, Meaghan, McGhee, Elisa A., Mitra, Ipsita, Nag, Amitabh, Giraldo, Luis Ocampo, Pearson, Karen, Plaisir, Mathieu, Popenhagen, Sarah K., Rassoul, Hamid, Giannone, Miro Ronac, Samnani, Mirza, Schmerr, Nicholas, Spillman, Kate, Srinivas, Girish, Takazawa, Samuel K., Tempert, Alex, Turley, Reagan, Van Beek, Cory, Viens, Loïc, Walsh, Owen A., Weinstein, Nathan, White, Robert, Williams, Brian, Wilson, Trevor C., Wyckoff, Shirin, Yamamoto, Masa-yuki, Yap, Zachary, Yoshiyama, Tyler, and Zeiler, Cleat
- Subjects
Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,Physics - Geophysics - Abstract
Sample Return Capsules (SRCs) entering Earth's atmosphere at hypervelocity from interplanetary space are a valuable resource for studying meteor phenomena. The 24 September 2023 arrival of the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) SRC provided an unprecedented chance for geophysical observations of a well-characterized source with known parameters, including timing and trajectory. A collaborative effort involving researchers from 16 institutions executed a carefully planned geophysical observational campaign at strategically chosen locations, deploying over 400 ground-based sensors encompassing infrasound, seismic, distributed acoustic sensing (DAS), and GPS technologies. Additionally, balloons equipped with infrasound sensors were launched to capture signals at higher altitudes. This campaign (the largest of its kind so far) yielded a wealth of invaluable data anticipated to fuel scientific inquiry for years to come. The success of the observational campaign is evidenced by the near-universal detection of signals across instruments, both proximal and distal. This paper presents a comprehensive overview of the collective scientific effort, field deployment, and preliminary findings. The early findings have the potential to inform future space missions and terrestrial campaigns, contributing to our understanding of meteoroid interactions with planetary atmospheres. Furthermore, the dataset collected during this campaign will improve entry and propagation models as well as augment the study of atmospheric dynamics and shock phenomena generated by meteoroids and similar sources., Comment: 87 pages, 14 figures
- Published
- 2024
- Full Text
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36. Functor calculus completions for retractive operadic algebras in spectra
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Carr, Matthew B. and Harper, John E.
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Mathematics - Algebraic Topology - Abstract
The aim of this paper is to study convergence of Bousfield-Kan completions with respect to the 1-excisive approximation of the identity functor and exotic convergence of the Taylor tower of the identity functor, for algebras over operads in spectra centered away from the null object. In Goodwillie's homotopy functor calculus, being centered away from the null object amounts to doing homotopy theory and functor calculus in the retractive setting.
- Published
- 2024
37. Oxidative stress and immune cell activation quantification in sepsis and non-sepsis critical care patients by neopterin/7,8-dihydroneopterin analysis
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Baxter-Parker Gregory, Gaddam Ravinder Reddy, Moltchanova Elena, Carr Anitra, Shaw Geoff, Chambers Stephen, and Gieseg Steven P.
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sepsis ,neopterin ,7,8-dihydroneopterin ,kidney function ,inflammation ,biomarkers ,Crystallography ,QD901-999 - Abstract
Introduction: Neopterin and 7,8-dihydroneopterin are used as biomarkers of oxidative stress and inflammation, but the effect of kidney function on these measurements has not been extensively explored. We examine the levels of oxidative stress, inflammation and kidney function in intensive patients and compare them to equivalent patients without sepsis.
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- 2020
- Full Text
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38. Thermal model in digital twin of vertical PV system helps to explain unexpected yield gains
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Carr Anna J., Liu Ji, Binani Ashish, Cesar Kay, and Van Aken Bas B.
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solar park ,digital twin ,vertical installation ,thermal behavior ,yield analysis ,Renewable energy sources ,TJ807-830 - Abstract
The business case of novel integrated applications of solar energy is often regarded as a straightforward extrapolation of standard solar parks. But when the design of the solar park is remarkably different from typical solar parks, the operating conditions of the PV panels could also be changed. We have applied the digital twin to an R&D location with nine rows of eight bifacial PV panels in a vertical east/west orientation with varying row-row distances. We simulated the in-plane irradiances, based on measured GHI, which turned out to be in good agreement with observations of in-plane irradiances. But, using default free-standing PV heat transfer coefficients, the modelled module temperatures were too high and the simulated module powers too low. Applying an in-house developed method, we found that the heat transfer coefficient Uc is nearly double, and the vertically placed modules operate at a much lower temperature. The adjusted value for Uc leads to a 2.5% higher annual energy yield and higher performance ratio, partially offsetting the energy loss due to the less than optimal configuration. In conclusion, the digital twin increased the understanding of the vertical PV system and support future decision making, for instance for the application of vertical PV in combination with agriculture, where the low ground coverage ratio of vertical PV matches well with the needs from the agricultural sector.
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- 2023
- Full Text
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39. Feasibility and impact of physical activity and lifestyle program for Aboriginal families with Machado-Joseph disease in the Top End of Australia
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Carr, Jennifer, Lalara, Joyce, Lalara, Gayangwa, Lalara, Gwen, Daniels, Bronwyn, Clough, Alan, Lowell, Anne, and Barker, Ruth N
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- 2024
40. Intrinsic motivation and perceived competence among junior doctors in managing ophthalmic disease
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Dutt, D D C S, Razavi, H, and Carr, S E
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- 2024
41. Assigned Group Work Is Associated with Increased Student Motivation and Perceptions of Belonging in an Asynchronous Online Physiology Laboratory Course
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Shea E. Carr, Thad E. Wilson, Stacey A. Slone, Leila W. Karanja, and Jennifer L. Osterhage
- Abstract
With the rise of online instruction, a better understanding of the factors that contribute to belonging and motivation in these contexts is essential to creating optimal learning environments. Although group work is known to be beneficial to student success, few studies have investigated its role in the context of asynchronous online courses. The present study addresses this gap through a survey of 146 undergraduate students in an asynchronous online physiology lab over two semesters, one with required group work and one without group work. Students were surveyed to evaluate the influence of group work on their motivation and sense of belonging, as well as their perceptions of inclusive and exclusive features of the course. Students assigned to groups had a higher sense of belonging (P = 0.006) and beliefs about their competence (P = 0.002) and perceived lower effort and psychological costs associated with the course (P = 0.04 and 0.04, respectively) compared to students not assigned to groups. Students assigned to groups reported that peer interactions made them feel included in the course (70% of coded responses) while those not assigned to groups valued instructor interactions (51% of coded responses) as inclusive. Negative peer interactions were commonly reported as exclusive by students assigned to groups (28% of coded responses) while a lack of peer interactions (23% of coded responses) made students not assigned to groups feel excluded. These data indicate that assigning groups in asynchronous online courses is an effective way to increase student motivation and perceptions of belonging.
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- 2024
- Full Text
- View/download PDF
42. 'Careering' -- Toward Radicalism in Radical Times: Links to Human Security and Sustainable Livelihoods
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Veronica Hopner and Stuart Colin Carr
- Abstract
In this Age of the Anthropocene, the world of work is being radically disrupted by mass precarity, rising wage and income inequality, habitat destruction, and the rise of artificial intelligence. Facing such insecurity, people, we show, are careering toward radical ways of making a living. They range from radical professionals to social media influencing and environmental activism. Human security is fundamentally enhanced by sustainable livelihoods, and we explore ways not only to de-radicalise, but also to accept and embrace radical careering, if and whenever it serves the purpose of making people's livelihoods more sustainable for society, economies, and ecosystems. The article concludes by introducing an Index of Sustainable Livelihoods (SL-I). Success to the successful. The Sustainable Livelihoods Index (SL-I) is designed to be a 'visible hand' for end-users, including career counsellors, students, and workers undergoing career transitions, by Corporate Responsibility Officers, and by government ministries supporting just workforce transitions into sustainable livelihoods.
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- 2024
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43. Landau-phonon polaritons in Dirac heterostructures.
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Wehmeier, Lukas, Xu, Suheng, Mayer, Rafael, Vermilyea, Brian, Tsuneto, Makoto, Dapolito, Michael, Pu, Rui, Du, Zengyi, Chen, Xinzhong, Zheng, Wenjun, Jing, Ran, Zhou, Zijian, Watanabe, Kenji, Taniguchi, Takashi, Gozar, Adrian, Li, Qiang, Kuzmenko, Alexey, Carr, G, Du, Xu, Fogler, Michael, Basov, D, and Liu, Mengkun
- Abstract
Polaritons are light-matter quasiparticles that govern the optical response of quantum materials at the nanoscale, enabling on-chip communication and local sensing. Here, we report Landau-phonon polaritons (LPPs) in magnetized charge-neutral graphene encapsulated in hexagonal boron nitride (hBN). These quasiparticles emerge from the interaction of Dirac magnetoexciton modes in graphene with the hyperbolic phonon polariton modes in hBN. Using infrared magneto-nanoscopy, we reveal the ability to completely halt the LPP propagation in real space at quantized magnetic fields, defying the conventional optical selection rules. The LPP-based nanoscopy also tells apart two fundamental many-body phenomena: the Fermi velocity renormalization and field-dependent magnetoexciton binding energies. Our results highlight the potential of magnetically tuned Dirac heterostructures for precise nanoscale control and sensing of light-matter interaction.
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- 2024
44. Constraints on the energy spectrum of the diffuse cosmic neutrino flux from the ANTARES neutrino telescope
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ANTARES Collaboration, Albert, A., Alves, S., André, M., Ardid, M., Ardid, S., Aubert, J. -J., Aublin, J., Baret, B., Basa, S., Becherini, Y., Belhorma, B., Bendahman, M., Benfenati, F., Bertin, V., Biagi, S., Boumaaza, J., Bouta, M., Bouwhuis, M. C., Brânzaş, H., Bruijn, R., Brunner, J., Busto, J., Caiffi, B., Calvo, D., Campion, S., Capone, A., Carenini, F., Carr, J., Carretero, V., Cartraud, T., Celli, S., Cerisy, L., Chabab, M., Moursli, R. Cherkaoui El, Chiarusi, T., Circella, M., Coelho, J. A. B., Coleiro, A., Coniglione, R., Coyle, P., Creusot, A., Díaz, A. F., De Martino, B., Distefano, C., Di Palma, I., Donzaud, C., Dornic, D., Drouhin, D., Eberl, T., Eddymaoui, A., van Eeden, T., van Eijk, D., Hedri, S. El, Khayati, N. El, Enzenhöfer, A., Fermani, P., Ferrara, G., Filippini, F., Fusco, L. A., Gagliardini, S., García, J., Oliver, C. Gatius, Gay, P., Geißelbrecht, N., Glotin, H., Gozzini, R., Ruiz, R. Gracia, Graf, K., Guidi, C., Haegel, L., van Haren, H., Heijboer, A. J., Hello, Y., Hennig, L., Hernández-Rey, J. J., Hößl, J., Huang, F., Illuminati, G., Jisse-Jung, B., de Jong, M., de Jong, P., Kadler, M., Kalekin, O., Katz, U., Kouchner, A., Kreykenbohm, I., Kulikovskiy, V., Lahmann, R., Lamoureux, M., Lazo, A., Lefèvre, D., Leonora, E., Levi, G., Stum, S. Le, Loucatos, S., Manczak, J., Marcelin, M., Margiotta, A., Marinelli, A., Martínez-Mora, J. A., Migliozzi, P., Moussa, A., Muller, R., Navas, S., Nezri, E., Fearraigh, B. Ó, Oukacha, E., Păun, A., Păvălaş, G. E., Peña-Martínez, S., Perrin-Terrin, M., Piattelli, P., Poirè, C., Popa, V., Pradier, T., Randazzo, N., Real, D., Riccobene, G., Romanov, A., Losa, A. Sánchez, Saina, A., Greus, F. Salesa, Samtleben, D. F. E., Sanguineti, M., Sapienza, P., Schüssler, F., Seneca, J., Spurio, M., Stolarczyk, Th., Taiuti, M., Tayalati, Y., Vallage, B., Vannoye, G., Van Elewyck, V., Viola, S., Vivolo, D., Wilms, J., Zavatarelli, S., Zegarelli, A., Zornoza, J. D., and Zúñiga, J.
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
High-significance evidences of the existence of a high-energy diffuse flux of cosmic neutrinos have emerged in the last decade from several observations by the IceCube Collaboration. The ANTARES neutrino telescope took data for 15 years in the Mediterranean Sea, from 2007 to 2022, and collected a high-purity all-flavour neutrino sample. The search for a diffuse cosmic neutrino signal using this dataset is presented in this article. This final analysis did not provide a statistically significant observation of the cosmic diffuse flux. However, this is converted into limits on the properties of the cosmic neutrino spectrum. In particular, given the sensitivity of the ANTARES neutrino telescope between 1 and 50 TeV, constraints on single-power-law hypotheses are derived for the cosmic diffuse flux below 20 TeV, especially for power-law fits of the IceCube data with spectral index softer than 2.8.
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- 2024
- Full Text
- View/download PDF
45. Optimization of Approximate Maps for Linear Systems Arising in Discretized PDEs
- Author
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Islam, Rishad, Carr, Arielle, and Jacobs, Colin
- Subjects
Mathematics - Numerical Analysis ,G.1.3 - Abstract
Generally, discretization of partial differential equations (PDEs) creates a sequence of linear systems $A_k x_k = b_k, k = 0, 1, 2, ..., N$ with well-known and structured sparsity patterns. Preconditioners are often necessary to achieve fast convergence When solving these linear systems using iterative solvers. We can use preconditioner updates for closely related systems instead of computing a preconditioner for each system from scratch. One such preconditioner update is the sparse approximate map (SAM), which is based on the sparse approximate inverse preconditioner using a least squares approximation. A SAM then acts as a map from one matrix in the sequence to another nearby one for which we have an effective preconditioner. To efficiently compute an effective SAM update (i.e., one that facilitates fast convergence of the iterative solver), we seek to compute an optimal sparsity pattern. In this paper, we examine several sparsity patterns for computing the SAM update to characterize optimal or near-optimal sparsity patterns for linear systems arising from discretized PDEs., Comment: 12 pages, 11 figures, submitted to Proceedings in Applied Mathematics and Mechanics (PAMM)
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- 2024
46. Final Search for Short-Baseline Neutrino Oscillations with the PROSPECT-I Detector at HFIR
- Author
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Andriamirado, M., Balantekin, B., Bass, C. D., Rodrigues, O. Benevides, Bernard, E. P., Bowden, N. S., Bryan, C. D., Carr, R., Classen, T., Conant, A. J., Deichert, G., Dolinski, M. J., Erickson, A., Galindo-Uribarri, A., Gokhale, S., Grant, C., Hans, S., Hansell, A. B., Heeger, K. M., Heffron, B., Jaffe, D. E., Jayakumar, S., Koblanski, J. R., Kunkle, P., Lane, C. E., Littlejohn, B. R., Sanchez, A. Lozano, Lu, X., Machado, F., Maricic, J., Mendenhall, M. P., Meyer, A. M., Milincic, R., Mueller, P. E., Mumm, H., Neilson, R., Qian, X., Roca, C., Rosero, R., Surukuchi, P., Sutanto, F., Venegas-Vargas, D., Weatherly, P. B., Wilhelmi, J., Yeh, M., Zhang, C., and Zhang, X.
- Subjects
High Energy Physics - Experiment ,Nuclear Experiment - Abstract
The PROSPECT experiment is designed to perform precise searches for antineutrino disappearance at short distances (7 - 9~m) from compact nuclear reactor cores. This Letter reports results from a new neutrino oscillation analysis performed using the complete data sample from the PROSPECT-I detector operated at the High Flux Isotope Reactor in 2018. The analysis uses a multi-period selection of inverse beta decay neutrino interactions with reduced backgrounds and enhanced statistical power to set limits on electron-flavor disappearance caused by mixing with sterile neutrinos with 0.2 - 20 eV$^2$ mass splittings. Inverse beta decay positron energy spectra from six different reactor-detector distance ranges are found to be statistically consistent with one another, as would be expected in the absence of sterile neutrino oscillations. The data excludes at 95% confidence level the existence of sterile neutrinos in regions above 3~eV$^2$ previously unexplored by terrestrial experiments, including all space below 10~eV$^2$ suggested by the recently strengthened Gallium Anomaly. The best-fit point of the Neutrino-4 reactor experiment's claimed observation of short-baseline oscillation is ruled out at more than five standard deviations., Comment: 6 pages, 4 figures
- Published
- 2024
47. Multivariate Predictors of LyC Escape II: Predicting LyC Escape Fractions for High-Redshift Galaxies
- Author
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Jaskot, Anne E., Silveyra, Anneliese C., Plantinga, Anna, Flury, Sophia R., Hayes, Matthew, Chisholm, John, Heckman, Timothy, Pentericci, Laura, Schaerer, Daniel, Trebitsch, Maxime, Verhamme, Anne, Carr, Cody, Ferguson, Henry C., Ji, Zhiyuan, Giavalisco, Mauro, Henry, Alaina, Marques-Chaves, Rui, Östlin, Göran, Saldana-Lopez, Alberto, Scarlata, Claudia, Worseck, Gábor, and Xu, Xinfeng
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
JWST is uncovering the properties of ever increasing numbers of galaxies at z>6, during the epoch of reionization. Connecting these observed populations to the process of reionization requires understanding how efficiently they produce Lyman continuum (LyC) photons and what fraction (fesc) of these photons escape into the intergalactic medium. By applying the Cox proportional hazards model, a survival analysis technique, to the Low-redshift Lyman Continuum Survey (LzLCS), we develop new, empirical, multivariate predictions for fesc. The models developed from the LzLCS reproduce the observed fesc for z~3 samples, which suggests that LyC emitters may share similar properties at low and high redshift. Our best-performing models for the z~3 galaxies include information about dust attenuation, ionization, and/or morphology. We then apply these models to z$\gtrsim$6 galaxies. For large photometric samples, we find a median predicted fesc=0.047-0.14. For smaller spectroscopic samples, which may include stronger emission line galaxies, we find that $\geq$33% of the galaxies have fesc >0.2, and we identify several candidate extreme leakers with fesc $\geq$0.5. The current samples show no strong trend between predicted fesc and UV magnitude, but limited spectroscopic information makes this result uncertain. Multivariate predictions can give significantly different results from single variable predictions, and the predicted fesc for high-redshift galaxies can differ significantly depending on whether star formation rate surface density or radius is used as a measure of galaxy morphology. We provide all parameters necessary to predict fesc for additional samples of high-redshift galaxies using these models., Comment: Accepted for publication in ApJ. 33 pages, 9 figures, 10 tables, plus appendix
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- 2024
48. Multivariate Predictors of LyC Escape I: A Survival Analysis of the Low-redshift Lyman Continuum Survey
- Author
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Jaskot, Anne E., Silveyra, Anneliese C., Plantinga, Anna, Flury, Sophia R., Hayes, Matthew, Chisholm, John, Heckman, Timothy, Pentericci, Laura, Schaerer, Daniel, Trebitsch, Maxime, Verhamme, Anne, Carr, Cody, Ferguson, Henry C., Ji, Zhiyuan, Giavalisco, Mauro, Henry, Alaina, Marques-Chaves, Rui, Östlin, Göran, Saldana-Lopez, Alberto, Scarlata, Claudia, Worseck, Gábor, and Xu, Xinfeng
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
To understand how galaxies reionized the universe, we must determine how the escape fraction of Lyman Continuum (LyC) photons (fesc) depends on galaxy properties. Using the z~0.3 Low-redshift Lyman Continuum Survey (LzLCS), we develop and analyze new multivariate predictors of fesc. These predictions use the Cox proportional hazards model, a survival analysis technique that incorporates both detections and upper limits. Our best model predicts the LzLCS fesc detections with a root-mean-square (RMS) scatter of 0.31 dex, better than single-variable correlations. According to ranking techniques, the most important predictors of fesc are the equivalent width (EW) of Lyman-series absorption lines and the UV dust attenuation, which track line-of-sight absorption due to HI and dust. The HI absorption EW is uniquely crucial for predicting fesc for the strongest LyC emitters, which show properties similar to weaker LyC emitters and whose high fesc may therefore result from favorable orientation. In the absence of HI information, star formation rate surface density ($\Sigma_{\rm SFR}$) and [O III]/[O II] ratio are the most predictive variables and highlight the connection between feedback and fesc. We generate a model suitable for z>6, which uses only the UV slope, $\Sigma_{\rm SFR}$, and [O III]/[O II]. We find that $\Sigma_{\rm SFR}$ is more important in predicting fesc at higher stellar masses, whereas [O III]/[O II] plays a greater role at lower masses. We also analyze predictions for other parameters, such as the ionizing-to-non ionizing flux ratio and Ly=alpha escape fraction. These multivariate models represent a promising tool for predicting fesc at high redshift., Comment: Accepted for publication in ApJ. 34 pages + appendix, 12 figures
- Published
- 2024
49. Reactor Antineutrino Directionality Measurement with the PROSPECT-I Detector
- Author
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Andriamirado, M., Balantekin, B., Bass, C. D., Rodrigues, O. Benevides, Bernard, E. P., Bowden, N. S., Bryan, C. D., Carr, R., Classen, T., Conant, A. J., Deichert, G., Dolinski, M. J., Erickson, A., Galindo-Uribarri, A., Gokhale, S., Grant, C., Hans, S., Hansell, A. B., Heeger, K. M., Heffron, B., Jaffe, D. E., Jayakumar, S., Jones, D. C., Koblanski, J. R., Kunkle, P., Lane, C. E., Littlejohn, B. R., Sanchez, A. Lozano, Lu, X., Maricic, J., Mendenhall, M. P., Meyer, A. M., Milincic, R., Mueller, P. E., Mumm, H., Napolitano, J., Nave, C., Neilson, R., Oueslati, M., Roca, C., Rosero, R., Surukuchi, P., Sutanto, F., Venegas-Vargas, D., Weatherly, P. B., Wilhelmi, J., Yeh, M., Zhang, C., and Zhang, X.
- Subjects
Nuclear Experiment ,High Energy Physics - Experiment ,Physics - Instrumentation and Detectors - Abstract
The PROSPECT-I detector has several features that enable measurement of the direction of a compact neutrino source. In this paper, a detailed report on the directional measurements made on electron antineutrinos emitted from the High Flux Isotope Reactor is presented. With an estimated true neutrino (reactor to detector) direction of $\phi = 40.8\unicode{xB0} \pm 0.7\unicode{xB0}$ and $\theta = 98.6\unicode{xB0} \pm 0.4\unicode{xB0}$, the PROSPECT-I detector is able to reconstruct an average neutrino direction of $\phi = 39.4\unicode{xB0} \pm 2.9\unicode{xB0}$ and $\theta = 97.6\unicode{xB0} \pm 1.6\unicode{xB0}$. This measurement is made with approximately 48000 Inverse Beta Decay signal events and is the most precise directional reconstruction of reactor antineutrinos to date.
- Published
- 2024
50. Equilibrium States of Galactic Atmospheres II: Interpretation and Implications
- Author
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Voit, G. M., Carr, C., Fielding, D. B., Pandya, V., Bryan, G. L., Donahue, M., Oppenheimer, B. D., and Somerville, R. S.
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
The scaling of galaxy properties with halo mass suggests that feedback loops regulate star formation, but there is no consensus yet about how those feedback loops work. To help clarify discussions of galaxy-scale feedback, Paper I presented a very simple model for supernova feedback that it called the minimalist regulator model. This followup paper interprets that model and discusses its implications. The model itself is an accounting system that tracks all of the mass and energy associated with a halo's circumgalactic baryons--the central galaxy's atmosphere. Algebraic solutions for the equilibrium states of that model reveal that star formation in low-mass halos self-regulates primarily by expanding the atmospheres of those halos, ultimately resulting in stellar masses that are insensitive to the mass-loading properties of galactic winds. What matters most is the proportion of supernova energy that couples with circumgalactic gas. However, supernova feedback alone fails to expand galactic atmospheres in higher-mass halos. According to the minimalist regulator model, an atmospheric contraction crisis ensues, which may be what triggers strong black-hole feedback. The model also predicts that circumgalactic medium properties emerging from cosmological simulations should depend largely on the specific energy of the outflows they produce, and we interpret the qualitative properties of several numerical simulations in light of that prediction., Comment: 15 pages, 3 figures, Submitted to ApJ
- Published
- 2024
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