144,748 results on '"Nolan, A."'
Search Results
2. Varstrometry for Off-nucleus and Dual sub-Kpc AGN (VODKA): A Mix of Singles, Lenses, and True Duals at Cosmic Noon
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Gross, Arran C., Chen, Yu-Ching, Oguri, Masamune, Nolan, Liam, Liu, Xin, Shen, Yue, Zhuang, Ming-Yang, Li, Junyao, Zakamska, Nadia L., Hwang, Hsiang-Chih, and Ishikawa, Yuzo
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Astrophysics - Astrophysics of Galaxies - Abstract
Dual Active Galactic Nuclei (dual AGNs), a phase in some galaxy mergers during which both central supermassive black holes (SMBHs) are active, are expected to be a key observable stage leading up to SMBH mergers. Constraining the population of dual AGNs in both the nearby and high-z universe has proven to be elusive until very recently. We present a multi-wavelength follow-up campaign to confirm the nature of a sample of 20 candidate dual AGNs at cosmic noon (z~2) from the VODKA sample. Through a combination of Hubble Space Telescope (HST) and Very Large Array (VLA) imaging, we refute the possibility of gravitational lensing in all but one target. We find evidence of dual AGNs in four systems, while seven exhibit single AGN in galaxy pairs, either through strong radio emission or ancillary emission line data. The remaining systems are either confirmed as quasar-star superpositions (six) or non-lensed pairs (two) that require further investigations to establish AGN activity. Among the systems with radio detections, we find a variety of radio spectral slopes and UV/optical colors suggesting that our sample contains a range of AGN properties, from obscured radio-quiet objects to those with powerful synchrotron-emitting jets. This study presents one of the largest dedicated multi-wavelength follow-up campaigns to date searching for dual AGNs at high redshift. We confirm several of the highest-z systems at small physical separations, thus representing some of the most evolved dual AGN systems at the epoch of peak quasar activity known to date., Comment: 26 pages, 8 figures, submitted to ApJ, includes appendix of 9 additional figures and 18 tables
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- 2024
3. Sequential Posterior Sampling with Diffusion Models
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Stevens, Tristan S. W., Nolan, Oisín, Robert, Jean-Luc, and van Sloun, Ruud J. G.
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
Diffusion models have quickly risen in popularity for their ability to model complex distributions and perform effective posterior sampling. Unfortunately, the iterative nature of these generative models makes them computationally expensive and unsuitable for real-time sequential inverse problems such as ultrasound imaging. Considering the strong temporal structure across sequences of frames, we propose a novel approach that models the transition dynamics to improve the efficiency of sequential diffusion posterior sampling in conditional image synthesis. Through modeling sequence data using a video vision transformer (ViViT) transition model based on previous diffusion outputs, we can initialize the reverse diffusion trajectory at a lower noise scale, greatly reducing the number of iterations required for convergence. We demonstrate the effectiveness of our approach on a real-world dataset of high frame rate cardiac ultrasound images and show that it achieves the same performance as a full diffusion trajectory while accelerating inference 25$\times$, enabling real-time posterior sampling. Furthermore, we show that the addition of a transition model improves the PSNR up to 8\% in cases with severe motion. Our method opens up new possibilities for real-time applications of diffusion models in imaging and other domains requiring real-time inference., Comment: 5 pages, 4 figures, preprint
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- 2024
4. Narrowing the Focus: Learned Optimizers for Pretrained Models
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Kristiansen, Gus, Sandler, Mark, Zhmoginov, Andrey, Miller, Nolan, Goyal, Anirudh, Lee, Jihwan, and Vladymyrov, Max
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Computer Science - Machine Learning - Abstract
In modern deep learning, the models are learned by applying gradient updates using an optimizer, which transforms the updates based on various statistics. Optimizers are often hand-designed and tuning their hyperparameters is a big part of the training process. Learned optimizers have shown some initial promise, but are generally unsuccessful as a general optimization mechanism applicable to every problem. In this work we explore a different direction: instead of learning general optimizers, we instead specialize them to a specific training environment. We propose a novel optimizer technique that learns a layer-specific linear combination of update directions provided by a set of base optimizers, effectively adapting its strategy to the specific model and dataset. When evaluated on image classification tasks, this specialized optimizer significantly outperforms both traditional off-the-shelf methods such as Adam, as well as existing general learned optimizers. Moreover, it demonstrates robust generalization with respect to model initialization, evaluating on unseen datasets, and training durations beyond its meta-training horizon.
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- 2024
5. Effect of Proton Irradiation in Thin-Film YBa$_2$Cu$_3$O$_{7-\delta}$ Superconductor
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Fogt, Joseph, Weeda, Hope, Harrison, Trevor, Miles, Nolan, and Cho, Kyuil
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Condensed Matter - Superconductivity - Abstract
We investigated the effect of 0.6 MeV proton irradiation on the superconducting and normal state properties of thin-film $\text{YBa}_{2}\text{Cu}_{3}\text{O}_{7-\delta}$ superconductors. A thin-film YBCO superconductor ($\approx$ 567 nm thick) was subject to a series of proton irradiations with a total fluence of $7.6\times10^{16}$ $\text{p/cm}^2$. Upon irradiation, $T_c$ was drastically decreased from 89.3 K towards zero with a corresponding increase in its normal state resistivity above $T_c$. This increase in resistivity which indicates the increase of defects inside the thin-film sample can be converted to the dimensionless scattering rate. We found that the relation between $T_c$ and dimensionless scattering rate obtained during proton irradiation approximates the generalized d-wave Abrikosov-Gor'kov theory better than the previous results obtained from electron irradiations. This is an unexpected result since the electron irradiation is known to be most effective to suppress superconductivity over other heavier ion irradiations such as proton irradiation. It suggests that the type of defects created by proton irradiation evolves from cascade defects (in bulk single crystals) to point-like defects (in thin-film single crystals) as the thickness decreases.
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- 2024
6. Mastering a Life-Saving Technique: Analysis of Learning from a Cricothyrotomy Workshop
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Cole J. Homer, Kristy Carlson, Nolan Marshall, Randi Peavy, Christopher M. Bingcang, John McClain, and Jayme R. Dowdall
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Cricothyrotomy is an emergency procedure that is utilized in situations that require immediate access to a breathing pathway. This procedure may be performed by professionals in a variety of healthcare fields depending upon the specific emergency scenario, so the development of an interprofessional workshop is imperative for procedural confidence and skill development. Our team developed a training workshop with a specific focus on procedural skills, risks, benefits, and psychological ramifications associated with a cricothyrotomy procedure. Pre-workshop and post-workshop surveys were obtained for comparison of participant confidence. Overall, the organization and delivery of a cricothyrotomy training workshop significantly increased the overall participant confidence surrounding this procedure.
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- 2024
7. How Discipline Shapes the Meaning of Value Creation in Higher Education; Implications for Enterprise, Entrepreneurship and Employability
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Lucy Hatt, Jane Nolan, and Carys Watts
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This paper sets out the importance of teaching contextualized understandings of value within different disciplinary contexts in order to enhance employability and to foster greater levels of engagement with enterprise and entrepreneurship education. Key research has recognised the broader benefits of enterprise and entrepreneurship education, including that of developing graduate employability. Yet enterprise and entrepreneurship may not feel comfortable or relevant to students (Enterprise Educators UK (EEUK), 2012; Henry, 2013). It has been identified that students can better relate to enterprise and entrepreneurship when it is contextualised in professions, sectors and communities of practice, moving away from a focus on venture creation and start up (Gibb, 2005). We argue that taking an approach which is explicitly based on value creation is a crucial driver of student engagement with enterprise and entrepreneurship education. This needs to be based in students' individual values, embedded in their disciplines, and related to the communities of practice which as graduates they will go on to be part of. When grounded in the creation of value at an individual, disciplinary, and societal level, enterprise and entrepreneurship education can appeal to a wider constituency of students. In this paper, we discuss how value creation is understood in three diverse academic disciplines, Business, Biomedical Science and Music. Building on key research and drawing on our extensive practice as educators, we argue that explicitly foregrounding understandings of value within our different disciplinary contexts and developing appropriately contextualized, experiential forms of value creation-based pedagogy, is key to student engagement and enhances graduate employability. [Note: The page range (1-20) shown on the PDF is incorrect. The correct page range is 1-15, 17-20.]
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- 2024
8. Implicit and Explicit Sequence Learning in Adults with Developmental Language Disorder
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Gabriel J. Cler, Samantha Bartolo, Jiwon Kim, Anna Nolan, and Sophia Banel
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Purpose: Developmental language disorder (DLD) is a neurodevelopmental disorder that impacts approximately 7% of the population and is characterized by unexplained deficits in expressive and/or receptive components of language. A common procedural learning task, serial reaction time (SRT), has been used to develop models of the basis of DLD. However, paradigms involve differing levels of implicit and explicit learning during this task, muddying interpretations of the data. Here, we tested adults with DLD on implicit and explicit SRT tasks to better understand implicit and explicit procedural learning in this population. We hypothesized that adults with DLD would demonstrate reduced learning on only the implicit SRT task, as alternate explicit neural mechanisms could lead to equivalent performance on the explicit task. Method: Fifty participants (25 with DLD and 25 with typical language) completed implicit and explicit SRT tasks, measuring their ability to learn visually presented 10-element sequences. Group differences were evaluated on sequence learning, error rates, and explicit recall of the sequence after learning. Results: Sequence learning was the same between the groups on both tasks. However, individuals with DLD showed increased errors and significantly worse recall of the explicitly learned sequence. Conclusions: Results suggest that sequence learning may be intact in this population, while aspects of explicit learning and motoric responses are impaired. Results are interpreted in light of a neurobiological model of DLD.
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- 2024
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9. Circulating Tumor DNA Assay Detects Merkel Cell Carcinoma Recurrence, Disease Progression, and Minimal Residual Disease: Surveillance and Prognostic Implications.
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Akaike, Tomoko, Thakuria, Manisha, Silk, Ann, Hippe, Daniel, Park, Song, So, Naomi, Maloney, Nolan, Gunnell, Lindsay, Eschholz, Alec, Kim, Emily, Sinha, Sumi, Hall, Evan, Bhatia, Shailender, Reddy, Sunil, Rodriguez, Angel, Aleshin, Alexey, Choi, Jacob, Tsai, Kenneth, Yom, Sue, Yu, Siegrid, Choi, Jaehyuk, Chandra, Sunandana, Nghiem, Paul, and Zaba, Lisa
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Humans ,Carcinoma ,Merkel Cell ,Male ,Female ,Circulating Tumor DNA ,Aged ,Neoplasm Recurrence ,Local ,Skin Neoplasms ,Prospective Studies ,Middle Aged ,Disease Progression ,Prognosis ,Aged ,80 and over ,Neoplasm ,Residual ,Biomarkers ,Tumor ,Adult - Abstract
PURPOSE: Merkel cell carcinoma (MCC) is an aggressive skin cancer with a 40% recurrence rate, lacking effective prognostic biomarkers and surveillance methods. This prospective, multicenter, observational study aimed to evaluate circulating tumor DNA (ctDNA) as a biomarker for detecting MCC recurrence. METHODS: Plasma samples, clinical data, and imaging results were collected from 319 patients. A tumor-informed ctDNA assay was used for analysis. Patients were divided into discovery (167 patients) and validation (152 patients) cohorts. Diagnostic performance, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), was assessed. RESULTS: ctDNA showed high sensitivity, 95% (discovery; 95% CI, 87 to 99) and 94% (validation; 95% CI, 85 to 98), for detecting disease at enrollment, with corresponding specificities of 90% (95% CI, 82 to 95) and 86% (95% CI, 77 to 93). A positive ctDNA during surveillance indicated increased recurrence risk, with hazard ratios (HRs) of 6.8 (discovery; 95% CI, 2.9 to 16) and 20 (validation; 95% CI, 8.3 to 50). The PPV for clinical recurrence at 1 year after a positive ctDNA test was 69% (discovery; 95% CI, 32 to 91) and 94% (validation; 95% CI, 71 to 100), respectively. The NPV at 135 days after a negative ctDNA test was 94% (discovery; 95% CI, 90 to 97) and 93% (validation; 95% CI, 89 to 97), respectively. Patients positive for ctDNA within 4 months after treatment had higher rates of recurrence, with 1-year rates of 74% versus 21% (adjusted HR, 7.4 [95% CI, 2.7 to 20]). CONCLUSION: ctDNA testing exhibited high prognostic accuracy in detecting MCC recurrence, suggesting its potential to reduce frequent surveillance imaging. ctDNA also identifies high-risk patients who need more frequent imaging and may be best suited for adjuvant therapy trials.
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- 2024
10. Transcranial Focused Ultrasound Targeting the Amygdala May Increase Psychophysiological and Subjective Negative Emotional Reactivity in Healthy Older Adults.
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Hoang-Dang, Bianca, Halavi, Sabrina, Rotstein, Natalie, Spivak, Norman, Dang, Nolan, Cvijanovic, Luka, Hiller, Sonja, Vallejo-Martelo, Mauricio, Rosenberg, Benjamin, Swenson, Andrew, Becerra, Sergio, Sun, Michael, Revett, Malina, Kronemyer, David, Berlow, Rustin, Craske, Michelle, Suthana, Nanthia, Monti, Martin, Zbozinek, Tomislav, Bookheimer, Susan, and Kuhn, Taylor
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Amygdala ,Emotional reactivity ,Low-intensity transcranial focused ultrasound (TFUS) ,Noninvasive deep brain stimulation ,Psychophysiology - Abstract
BACKGROUND: The amygdala is highly implicated in an array of psychiatric disorders but is not accessible using currently available noninvasive neuromodulatory techniques. Low-intensity transcranial focused ultrasound (TFUS) is a neuromodulatory technique that has the capability of reaching subcortical regions noninvasively. METHODS: We studied healthy older adult participants (N = 21, ages 48-79 years) who received TFUS targeting the right amygdala and left entorhinal cortex (active control region) using a 2-visit within-participant crossover design. Before and after TFUS, behavioral measures were collected via the State-Trait Anxiety Inventory and an emotional reactivity and regulation task utilizing neutral and negatively valenced images from the International Affective Picture System. Heart rate and self-reported emotional valence and arousal were measured during the emotional reactivity and regulation task to investigate subjective and physiological responses to the task. RESULTS: Significant increases in both self-reported arousal in response to negative images and heart rate during emotional reactivity and regulation task intertrial intervals were observed when TFUS targeted the amygdala; these changes were not evident when the entorhinal cortex was targeted. No significant changes were found for state anxiety, self-reported valence to the negative images, cardiac response to the negative images, or emotion regulation. CONCLUSIONS: The results of this study provide preliminary evidence that a single session of TFUS targeting the amygdala may alter psychophysiological and subjective emotional responses, indicating some potential for future neuropsychiatric applications. However, more work on TFUS parameters and targeting optimization is necessary to determine how to elicit changes in a more clinically advantageous way.
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- 2024
11. Characterizing Long COVID in Children and Adolescents
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Gross, Rachel S, Thaweethai, Tanayott, Kleinman, Lawrence C, Snowden, Jessica N, Rosenzweig, Erika B, Milner, Joshua D, Tantisira, Kelan G, Rhee, Kyung E, Jernigan, Terry L, Kinser, Patricia A, Salisbury, Amy L, Warburton, David, Mohandas, Sindhu, Wood, John C, Newburger, Jane W, Truong, Dongngan T, Flaherman, Valerie J, Metz, Torri D, Karlson, Elizabeth W, Chibnik, Lori B, Pant, Deepti B, Krishnamoorthy, Aparna, Gallagher, Richard, Lamendola-Essel, Michelle F, Hasson, Denise C, Katz, Stuart D, Yin, Shonna, Dreyer, Benard P, Carmilani, Megan, Coombs, K, Fitzgerald, Megan L, Güthe, Nick, Hornig, Mady, Letts, Rebecca J, Peddie, Aimee K, Taylor, Brittany D, Foulkes, Andrea S, Stockwell, Melissa S, Balaraman, Venkataraman, Bogie, Amanda, Bukulmez, Hulya, Dozor, Allen J, Eckrich, Daniel, Elliott, Amy J, Evans, Danielle N, Farkas, Jonathan S, Faustino, E Vincent S, Fischer, Laura, Gaur, Sunanda, Harahsheh, Ashraf S, Hasan, Uzma N, Hsia, Daniel S, Huerta-Montanez, Gredia, Hummel, Kathy D, Kadish, Matt P, Kaelber, David C, Krishnan, Sankaran, Kosut, Jessica S, Larrabee, Jerry, Lim, Peter Paul C, Michelow, Ian C, Oliveira, Carlos R, Raissy, Hengameh, Rosario-Pabon, Zaira, Ross, Judith L, Sato, Alice I, Stevenson, Michelle D, Talavera-Barber, Maria M, Teufel, Ronald J, Weakley, Kathryn E, Zimmerman, Emily, Bind, Marie-Abele C, Chan, James, Guan, Zoe, Morse, Richard E, Reeder, Harrison T, Akshoomoff, Natascha, Aschner, Judy L, Bhattacharjee, Rakesh, Cottrell, Lesley A, Cowan, Kelly, D'Sa, Viren A, Fiks, Alexander G, Gennaro, Maria L, Irby, Katherine, Khare, Manaswitha, Landeo Guttierrez, Jeremy, McCulloh, Russell J, Narang, Shalu, Ness- Cochinwala, Manette, Nolan, Sheila, Palumbo, Paul, Ryu, Julie, Salazar, Juan C, Selvarangan, Rangaraj, Stein, Cheryl R, Werzberger, Alan, Zempsky, William T, Aupperle, Robin, and Baker, Fiona C
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Biomedical and Clinical Sciences ,Clinical Sciences ,Health Sciences ,Emerging Infectious Diseases ,Neurosciences ,Coronaviruses ,Infectious Diseases ,Pediatric ,Minority Health ,Pain Research ,Infection ,Good Health and Well Being ,RECOVER-Pediatrics Consortium ,RECOVER-Pediatrics Group Authors ,Medical and Health Sciences ,General & Internal Medicine ,Biomedical and clinical sciences ,Health sciences - Abstract
ImportanceMost research to understand postacute sequelae of SARS-CoV-2 infection (PASC), or long COVID, has focused on adults, with less known about this complex condition in children. Research is needed to characterize pediatric PASC to enable studies of underlying mechanisms that will guide future treatment.ObjectiveTo identify the most common prolonged symptoms experienced by children (aged 6 to 17 years) after SARS-CoV-2 infection, how these symptoms differ by age (school-age [6-11 years] vs adolescents [12-17 years]), how they cluster into distinct phenotypes, and what symptoms in combination could be used as an empirically derived index to assist researchers to study the likely presence of PASC.Design, setting, and participantsMulticenter longitudinal observational cohort study with participants recruited from more than 60 US health care and community settings between March 2022 and December 2023, including school-age children and adolescents with and without SARS-CoV-2 infection history.ExposureSARS-CoV-2 infection.Main outcomes and measuresPASC and 89 prolonged symptoms across 9 symptom domains.ResultsA total of 898 school-age children (751 with previous SARS-CoV-2 infection [referred to as infected] and 147 without [referred to as uninfected]; mean age, 8.6 years; 49% female; 11% were Black or African American, 34% were Hispanic, Latino, or Spanish, and 60% were White) and 4469 adolescents (3109 infected and 1360 uninfected; mean age, 14.8 years; 48% female; 13% were Black or African American, 21% were Hispanic, Latino, or Spanish, and 73% were White) were included. Median time between first infection and symptom survey was 506 days for school-age children and 556 days for adolescents. In models adjusted for sex and race and ethnicity, 14 symptoms in both school-age children and adolescents were more common in those with SARS-CoV-2 infection history compared with those without infection history, with 4 additional symptoms in school-age children only and 3 in adolescents only. These symptoms affected almost every organ system. Combinations of symptoms most associated with infection history were identified to form a PASC research index for each age group; these indices correlated with poorer overall health and quality of life. The index emphasizes neurocognitive, pain, and gastrointestinal symptoms in school-age children but change or loss in smell or taste, pain, and fatigue/malaise-related symptoms in adolescents. Clustering analyses identified 4 PASC symptom phenotypes in school-age children and 3 in adolescents.Conclusions and relevanceThis study developed research indices for characterizing PASC in children and adolescents. Symptom patterns were similar but distinguishable between the 2 groups, highlighting the importance of characterizing PASC separately for these age ranges.
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- 2024
12. Measurement of the $^8$B Solar Neutrino Flux Using the Full SNO+ Water Phase
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Collaboration, SNO, Allega, A., Anderson, M. R., Andringa, S., Askins, M., Auty, D. J., Bacon, A., Baker, J., Barão, F., Barros, N., Bayes, R., Beier, E. W., Bialek, A., Biller, S. D., Blucher, E., Caden, E., Callaghan, E. J., Chen, M., Cheng, S., Cleveland, B., Cookman, D., Corning, J., Cox, M. A., Dehghani, R., Deloye, J., Depatie, M. M., Di Lodovico, F., Dima, C., Dittmer, J., Dixon, K. H., Esmaeilian, M. S., Falk, E., Fatemighomi, N., Ford, R., Gaur, A., González-Reina, O. I., Gooding, D., Grant, C., Grove, J., Hall, S., Hallin, A. L., Hallman, D., Heintzelman, W. J., Helmer, R. L., Hewitt, C., Howard, V., Hreljac, B., Hu, J., Huang, P., Hunt-Stokes, R., Hussain, S. M. A., Inácio, A. S., Jillings, C. J., Kaluzienski, S., Kaptanoglu, T., Khan, H., Kladnik, J., Klein, J. R., Kormos, L. L., Krar, B., Kraus, C., Krauss, C. B., Kroupová, T., Lake, C., Lebanowski, L., Lefebvre, C., Lozza, V., Luo, M., Maio, A., Manecki, S., Maneira, J., Martin, R. D., McCauley, N., McDonald, A. B., Milton, G., Colina, A. Molina, Morris, D., Mubasher, M., Naugle, S., Nolan, L. J., O'Keeffe, H. M., Gann, G. D. Orebi, Page, J., Paleshi, K., Parker, W., Paton, J., Peeters, S. J. M., Pickard, L., Quenallata, B., Ravi, P., Reichold, A., Riccetto, S., Rose, J., Rosero, R., Semenec, I., Simms, J., Skensved, P., Smiley, M., Smith, J., Svoboda, R., Tam, B., Tseng, J., Vázquez-Jáuregui, E., Veinot, J. G. C., Virtue, C. J., Ward, M., Weigand, J. J., Wilson, J. R., Wilson, J. D., Wright, A., Yang, S., Yeh, M., Ye, Z., Yu, S., Zhang, Y., Zuber, K., and Zummo, A.
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High Energy Physics - Experiment - Abstract
The SNO+ detector operated initially as a water Cherenkov detector. The implementation of a sealed covergas system midway through water data taking resulted in a significant reduction in the activity of $^{222}$Rn daughters in the detector and allowed the lowest background to the solar electron scattering signal above 5 MeV achieved to date. This paper reports an updated SNO+ water phase $^8$B solar neutrino analysis with a total livetime of 282.4 days and an analysis threshold of 3.5 MeV. The $^8$B solar neutrino flux is found to be $\left(2.32^{+0.18}_{-0.17}\text{(stat.)}^{+0.07}_{-0.05}\text{(syst.)}\right)\times10^{6}$ cm$^{-2}$s$^{-1}$ assuming no neutrino oscillations, or $\left(5.36^{+0.41}_{-0.39}\text{(stat.)}^{+0.17}_{-0.16}\text{(syst.)} \right)\times10^{6}$ cm$^{-2}$s$^{-1}$ assuming standard neutrino oscillation parameters, in good agreement with both previous measurements and Standard Solar Model Calculations. The electron recoil spectrum is presented above 3.5 MeV.
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- 2024
13. High-Throughput Identification and Statistical Analysis of Atomically Thin Semiconductors
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Crimmann, Juri G., Junker, Moritz N., Glauser, Yannik M., Lassaline, Nolan, Nagamine, Gabriel, and Norris, David J.
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Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Materials Science - Abstract
Transition metal dichalcogenides (TMDs) are layered two-dimensional semiconductors explored for various optoelectronic applications, ranging from light-emitting diodes to single-photon emitters. To interact strongly with light, such devices require monolayer TMDs, which exhibit a direct bandgap. These atomically thin sheets are typically obtained through mechanical exfoliation followed by manual identification with a brightfield optical microscope. While this traditional procedure provides high-quality crystals, the identification step is time-intensive, low-throughput, and prone to human error, creating a significant bottleneck for TMD research. Here, we report a simple and fully automated approach for high-throughput identification of TMD monolayers using photoluminescence microscopy. Compared to a manual search and verification, our methodology offers a four-orders-of-magnitude decrease in the time a researcher must invest per identified monolayer. This ability enables us to measure geometric and photoluminescence-intensity features of more than 2,400 monolayers and bilayers of WSe$_2$, MoSe$_2$, and MoS$_2$. Due to these large numbers, we can study and quantify material properties previously inaccessible. For example, we show that the mean photoluminescence intensity from a monolayer correlates with its size due to reduced emission from its edges. Further, we observe large variations in brightness (up to 10$\times$) from WSe$_2$ monolayers of different batches produced by the same supplier. Therefore, our automated approach not only increases fabrication efficiency but also enhances sample quality for optoelectronic devices of atomically thin semiconductors.
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- 2024
14. ZTF SN Ia DR2: The spectral diversity of Type Ia supernovae in a volume-limited sample
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Burgaz, U., Maguire, K., Dimitriadis, G., Harvey, L., Senzel, R., Sollerman, J., Nordin, J., Galbany, L., Rigault, M., Smith, M., Goobar, A., Johansson, J., Rosnet, P., Amenouche, M., Deckers, M., Dhawan, S., Ginolin, M., Kim, Y. -L., Miller, A. A., Muller-Bravo, T. E., Nugent, P. E., Terwel, J. H., Dekany, R., Drake, A., Graham, M. J., Groom, S. L., Kasliwal, M. M., Kulkarni, S. R., Nolan, K., Nir, G., Riddle, R. L., Rusholme, B., and Sharma, Y.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
More than 3000 spectroscopically confirmed Type Ia supernovae (SNe Ia) are presented in the Zwicky Transient Facility SN Ia Data Release 2 (ZTF DR2). In this paper, we detail the spectral properties of 482 SNe Ia near maximum light, up to a redshift limit of $z$ $\leq$ 0.06. We measure the velocities and pseudo-equivalent widths (pEW) of key spectral features (Si II $\lambda$5972 and Si II $\lambda$6355) and investigate the relation between the properties of the spectral features and the photometric properties from the SALT2 light-curve parameters as a function of spectroscopic sub-class. We discuss the non-negligible impact of host galaxy contamination on SN Ia spectral classifications, as well as investigate the accuracy of spectral template matching of the ZTF DR2 sample. We define a new subclass of underluminous SNe Ia (`04gs-like') that lie spectroscopically between normal SNe Ia and transitional 86G-like SNe Ia (stronger Si II $\lambda$5972 than normal SNe Ia but significantly weaker Ti II features than `86G-like' SNe). We model these `04gs-like' SN Ia spectra using the radiative-transfer spectral synthesis code tardis and show that cooler temperatures alone are unable to explain their spectra; some changes in elemental abundances are also required. However, the broad continuity in spectral properties seen from bright (`91T-like') to faint normal SN Ia, including the transitional and 91bg-like SNe Ia, suggests that variations within a single explosion model may be able to explain their behaviour.
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- 2024
15. Probing populations of dark stellar remnants in the globular clusters 47 Tuc and Terzan 5 using pulsar timing
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Smith, Peter J., Hénault-Brunet, Vincent, Dickson, Nolan, Gieles, Mark, and Baumgardt, Holger
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Astrophysics - Astrophysics of Galaxies - Abstract
We present a new method to combine multimass equilibrium dynamical models and pulsar timing data to constrain the mass distribution and remnant populations of Milky Way globular clusters (GCs). We first apply this method to 47 Tuc, a cluster for which there exists an abundance of stellar kinematic data and which is also host to a large population of millisecond pulsars. We demonstrate that the pulsar timing data allow us to place strong constraints on the overall mass distribution and remnant populations even without fitting on stellar kinematics. Our models favor a small population of stellar-mass BHs in this cluster (with a total mass of $446^{+75}_{-72} \mathrm{M_\odot}$), arguing against the need for a large ($ > 2000 \ \mathrm{M_\odot}$) central intermediate-mass black hole. We then apply the method to Terzan 5, a heavily obscured bulge cluster which hosts the largest population of millisecond pulsars of any Milky Way GC and for which the collection of conventional stellar kinematic data is very limited. We improve existing constraints on the mass distribution and structural parameters of this cluster and place stringent constraints on its black hole content, finding an upper limit on the mass in BHs of $\sim 4000 \ \mathrm{M_\odot}$. This method allows us to probe the central dynamics of GCs even in the absence of stellar kinematic data and can be easily applied to other GCs with pulsar timing data, for which datasets will continue to grow with the next generation of radio telescopes., Comment: 33 pages, 19 figures. Accepted for publication in ApJ
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- 2024
16. Off-Grid Ultrasound Imaging by Stochastic Optimization
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van de Schaft, Vincent, Nolan, Oisín, and van Sloun, Ruud J. G.
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Electrical Engineering and Systems Science - Signal Processing - Abstract
Ultrasound images formed by delay-and-sum beamforming are plagued by artifacts that only clear up after compounding many transmissions. Some prior works pose imaging as an inverse problem. This approach can yield high image quality with few transmits, but requires a very fine image grid and is not robust to changes in measurement model parameters. We present INverse grid-Free Estimation of Reflectivities (INFER), an off-grid and stochastic algorithm that solves the inverse scattering problem in ultrasound imaging. Our method jointly optimizes for the locations of the gridpoints, their reflectivities, and the measurement model parameters such as the speed of sound. This approach allows us to use significantly fewer gridpoints, while obtaining better contrast and resolution and being more robust to changes in the imaging target and the hardware. The use of stochastic optimization enables solving for multiple transmissions simultaneously without increasing the required memory or computational load per iteration. We show that our method works across different imaging targets and across different transmit schemes and compares favorably against other beamforming and inverse solvers. The source code and the dataset to reproduce the results in this paper are available at www.github.com/vincentvdschaft/off-grid-ultrasound.
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- 2024
17. Imaging of single barium atoms in a second matrix site in solid xenon for barium tagging in a $^{136}$Xe double beta decay experiment
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Yvaine, M., Fairbank, D., Soderstrom, J., Taylor, C., Stanley, J., Walton, T., Chambers, C., Iverson, A., Fairbank, W., Kharusi, S. Al, Amy, A., Angelico, E., Anker, A., Arnquist, I. J., Atencio, A., Bane, J., Belov, V., Bernard, E. P., Bhatta, T., Bolotnikov, A., Breslin, J., Breur, P. A., Brodsky, J. P., Brown, E., Brunner, T., Caden, E., Cao, G. F., Cesmecioglu, D., Chambers, E., Chana, B., Chernyak, D., Chiu, M., Collister, R., Cvitan, M., Daniels, T., Darroch, L., DeVoe, R., di Vacri, M. L., Dolinski, M. J., Eckert, B., Elbeltagi, M., Elmansali, R., Fatemighomi, N., Foust, B., Fu, Y. S., Gallacher, D., Gallice, N., Giacomini, G., Gillis, W., Gingras, C., Gornea, R., Gratta, G., Hardy, C. A., Hedges, S., Hein, E., Holt, J. D., Hoppe, E. W., Karelin, A., Keblbeck, D., Kotov, I., Kuchenkov, A., Kumar, K. S., Kwiatkowski, A. A., Larson, A., Latif, M. B., Leach, K. G., Lennarz, A., Leonard, D. S., Lewis, H., Li, G., Li, Z., Licciardi, C., Lindsay, R., MacLellan, R., Majidi, S., Malbrunot, C., Masbou, J., McMichael, K., Peregrina, M. Medina, Moe, M., Mong, B., Moore, D. C., Natzke, C. R., Ngwadla, X. E., Ni, K., Nolan, A., Nowicki, S. C., Ondze, J. C. Nzobadila, Odian, A., Orrell, J. L., Ortega, G. S., Overman, C. T., Pagani, L., Smalley, H. Peltz, Perna, A., Pocar, A., Radeka, V., Raguzin, E., Rasiwala, H., Ray, D., Rescia, S., Richardson, G., Ross, R., Rowson, P. C., Saldanha, R., Sangiorgio, S., Schwartz, S., Sekula, S., Si, L., Soma, A. K., Spadoni, F., Stekhanov, V., Sun, X. L., Thibado, S., Tidball, A., Totev, T., Triambak, S., Tsang, T., Tyuka, O. A., van Bruggen, E., Vidal, M., Walent, M., Wamba, K., Wang, H. W., Wang, Q. D., Wang, W., Wang, Y. G., Watts, M., Wehrfritz, M., Wen, L. J., Wichoski, U., Wilde, S., Worcester, M., Xu, H., Yang, L., Yu, M., and Zeldovich, O.
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Physics - Atomic Physics ,High Energy Physics - Experiment ,Nuclear Experiment - Abstract
Neutrinoless double beta decay is one of the most sensitive probes for new physics beyond the Standard Model of particle physics. One of the isotopes under investigation is $^{136}$Xe, which would double beta decay into $^{136}$Ba. Detecting the single $^{136}$Ba daughter provides a sort of ultimate tool in the discrimination against backgrounds. Previous work demonstrated the ability to perform single atom imaging of Ba atoms in a single-vacancy site of a solid xenon matrix. In this paper, the effort to identify signal from individual barium atoms is extended to Ba atoms in a hexa-vacancy site in the matrix and is achieved despite increased photobleaching in this site. Abrupt fluorescence turn-off of a single Ba atom is also observed. Significant recovery of fluorescence signal lost through photobleaching is demonstrated upon annealing of Ba deposits in the Xe ice. Following annealing, it is observed that Ba atoms in the hexa-vacancy site exhibit antibleaching while Ba atoms in the tetra-vacancy site exhibit bleaching. This may be evidence for a matrix site transfer upon laser excitation. Our findings offer a path of continued research toward tagging of Ba daughters in all significant sites in solid xenon., Comment: 9 pages, 8 figures
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- 2024
18. Calibrating and standardizing the Tip of the Red Giant Branch in the Small Magellanic Cloud using small-amplitude red giants
- Author
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Koblischke, Nolan W. and Anderson, Richard I.
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We investigate the absolute calibration of the Tip of the Red Giant Branch (TRGB) in the Small Magellanic Cloud (SMC) using small amplitude red giant stars (SARGs) classified by the Optical Gravitational Lensing Experiment (OGLE). We show that all stars near the SMC's TRGB are SARGs. Distinguishing older and younger RGs near the Tip according to two period-luminosity sequences labeled A and B, we show many similarities among SARG populations of the LMC and the SMC, along with notable differences. Specifically, SMC SARGs have shorter periods due to lower metallicity and lower amplitudes due to younger ages than LMC SARGs. We discover two period-color relations near the TRGB that span all A-sequence and B-sequence stars in the OGLE-III footprints of the SMC and LMC, and we investigate using periods instead of color for TRGB standardization. Using variability derived information only, we trace the SMC's age and metallicity gradients and show the core to be populated by younger, more metal rich RGs. B-sequence SARGs yield both the most precise and the brightest tip magnitude, and they are best suited for distance determination and Hubble constant measurements because they correspond to the oldest stars near TRGB. Assuming the geometric distance measured by detached eclipsing binaries, the B-sequence yields the SMC's most accurate TRGB calibration to date: M_{F814W,syn} = -4.057 \pm 0.019(stat.) \pm 0.029(syst.) mag (1.5% in distance). Further study of SARGs will unravel the impact of population diversity on TRGB distances and further improve TRGB standardization., Comment: 20 pages, 13 figures, submitted for peer-review. Comments welcome!
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- 2024
19. Imaging of I Zw 18 by JWST: II. Spatially resolved star formation history
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Bortolini, Giacomo, Östlin, Göran, Habel, Nolan, Hirschauer, Alec S., Jones, Olivia C., Justtanont, Kay, Meixner, Margaret, Boyer, Martha L., Blommaert, Joris A. D. L., Crouzet, Nicolas, Lenkić, Nally, Conor, Sargent, Beth A., van der Werf, Paul, Güdel, Manuel, Henning, Thomas, and Lagage, Pierre O.
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Astrophysics - Astrophysics of Galaxies - Abstract
The blue compact dwarf galaxy I Zw 18 is one of the most metal-poor ($Z \sim 3% Z_{\sun}$) star-forming galaxies in the local Universe. Its evolutionary status has sparked debate within the astronomical community. We aim to investigate the stellar populations of I Zw 18 in the near-IR using JWST/NIRCam's high spatial resolution and sensitivity. Additionally, we aim to derive the galaxy's spatially resolved star formation history (SFH) over the last 1 Gyr and provide constraints for older epochs. We used DOLPHOT to measure positions and fluxes of point sources in the F115W and F200W filters' images of I Zw 18. To derive I Zw 18's SFH, we applied the color-magnitude diagram (CMD) fitting technique SFERA 2.0, using two independent sets of stellar models. Our analysis reveals three main stellar populations: one younger than $\sim30$ Myr, mainly in the northwest star-forming (SF) region; an intermediate-age population ($\sim 100 - 800$ Myr) in the southeast SF region; and a red and faint population linked to the underlying halo, older than 1 Gyr and possibly as old as 13.8 Gyr. The main body of the galaxy shows a very low star formation rate (SFR) of $\sim 10^{-4} M_{\odot} \text{yr}^{-1}$ between 1 and 13.8 Gyr ago. In the last billion years, I Zw 18 shows increasing SF, with strong bursts around $\sim10$ and $\sim100$ Myr ago. Component C mirrors the main body's evolution but with lower SFRs. Our findings confirm that I Zw 18 contains stars of all ages, indicating it is not a young galaxy but has an old stellar halo, similar to other BCDs. The low SF activity over the past billion years supports the "slow cooking" dwarf scenario, explaining its low metal content. Currently, the galaxy is undergoing its strongest SF episode ($\sim 0.6 M_{\odot} \text{yr}^{-1}$) mainly in the northwest region, likely due to a recent gravitational interaction with Component C., Comment: 14 pages, 11 figures, accepted for publications in Astronomy & Astrophysics (section "4. Extragalactic astronomy")
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- 2024
20. Active Diffusion Subsampling
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Nolan, Oisin, Stevens, Tristan S. W., van Nierop, Wessel L., and van Sloun, Ruud J. G.
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Computer Science - Machine Learning - Abstract
Subsampling is commonly used to mitigate costs associated with data acquisition, such as time or energy requirements, motivating the development of algorithms for estimating the fully-sampled signal of interest $x$ from partially observed measurements $y$. In maximum-entropy sampling, one selects measurement locations that are expected to have the highest entropy, so as to minimize uncertainty about $x$. This approach relies on an accurate model of the posterior distribution over future measurements, given the measurements observed so far. Recently, diffusion models have been shown to produce high-quality posterior samples of high-dimensional signals using guided diffusion. In this work, we propose Active Diffusion Subsampling (ADS), a method for performing active subsampling using guided diffusion in which the model tracks a distribution of beliefs over the true state of $x$ throughout the reverse diffusion process, progressively decreasing its uncertainty by choosing to acquire measurements with maximum expected entropy, and ultimately generating the posterior distribution $p(x | y)$. ADS can be applied using pre-trained diffusion models for any subsampling rate, and does not require task-specific retraining - just the specification of a measurement model. Furthermore, the maximum entropy sampling policy employed by ADS is interpretable, enhancing transparency relative to existing methods using black-box policies. Experimentally, we show that ADS outperforms fixed sampling strategies, and study an application of ADS in Magnetic Resonance Imaging acceleration using the fastMRI dataset, finding that ADS performs competitively with supervised methods. Code available at https://active-diffusion-subsampling.github.io/., Comment: 17 pages, 12 figures, preprint
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- 2024
21. MMIL: A novel algorithm for disease associated cell type discovery
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Craig, Erin, Keyes, Timothy, Sarno, Jolanda, Zaslavsky, Maxim, Nolan, Garry, Davis, Kara, Hastie, Trevor, and Tibshirani, Robert
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Quantitative Biology - Quantitative Methods ,Computer Science - Machine Learning ,Statistics - Methodology - Abstract
Single-cell datasets often lack individual cell labels, making it challenging to identify cells associated with disease. To address this, we introduce Mixture Modeling for Multiple Instance Learning (MMIL), an expectation maximization method that enables the training and calibration of cell-level classifiers using patient-level labels. Our approach can be used to train e.g. lasso logistic regression models, gradient boosted trees, and neural networks. When applied to clinically-annotated, primary patient samples in Acute Myeloid Leukemia (AML) and Acute Lymphoblastic Leukemia (ALL), our method accurately identifies cancer cells, generalizes across tissues and treatment timepoints, and selects biologically relevant features. In addition, MMIL is capable of incorporating cell labels into model training when they are known, providing a powerful framework for leveraging both labeled and unlabeled data simultaneously. Mixture Modeling for MIL offers a novel approach for cell classification, with significant potential to advance disease understanding and management, especially in scenarios with unknown gold-standard labels and high dimensionality., Comment: Erin Craig and Timothy Keyes contributed equally to this work
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- 2024
22. NIRPS first light and early science: breaking the 1 m/s RV precision barrier at infrared wavelengths
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Artigau, Étienne, Bouchy, François, Doyon, René, Baron, Frédérique, Malo, Lison, Wildi, François, Pepe, Franceso, Cook, Neil J., Thibault, Simon, Reshetov, Vladimir, Dumusque, Xavier, Lovis, Christophe, Sosnowska, Danuta, Martins, Bruno L. Canto, De Medeiros, Jose Renan, Delfosse, Xavier, Santos, Nuno, Rebolo, Rafael, Abreu, Manuel, Allain, Guillaume, Allart, Romain, Auger, Hugues, Barros, Susana, Bazinet, Luc, Blind, Nicolas, Boisse, Isabelle, Bonfils, Xavier, Bourrier, Vincent, Bovay, Sébastien, Broeg, Christopher, Brousseau, Denis, Bruniquel, Vincent, Cabral, Alexandre, Cadieux, Charles, Carmona, Andres, Carteret, Yann, Challita, Zalpha, Chazelas, Bruno, Cloutier, Ryan, Coelho, João, Cointepas, Marion, Conod, Uriel, Cowan, Nicolas, Cristo, Eduardo, da Silva, João Gomes, Dauplaise, Laurie, Gomes, Roseane de Lima, Delgado-Mena, Elisa, Ehrenreich, David, Faria, João, Figueira, Pedro, Forveille, Thierry, Frensch, Yolanda, Gagné, Jonathan, Genest, Frédéric, Genolet, Ludovic, Hernández, Jonay I. González, Témich, Félix Gracia, Grieves, Nolan, Hernandez, Olivier, Hobson, Melissa J., Hoeijmakers, Jens, Kerley, Dan, Krishnamurthy, Vigneshwaran, Lafrenière, David, Lamontagne, Pierrot, Larue, Pierre, Leaf, Henry, Leão, Izan C., Lim, Olivia, Curto, Gaspare Lo, Martins, Allan M., Melo, Claudio, Messias, Yuri S., Mignon, Lucile, Moranta, Leslie, Mordasini, Christoph, Moulla, Khaled Al, Mounzer, Dany, L'Heureux, Alexandrine, Nari, Nicola, Nielsen, Louise, Osborn, Ares, Parc, Léna, Pasquini, Luca, Passegger, Vera M., Pelletier, Stefan, Peroux, Céline, Piaulet, Caroline, Plotnykov, Mykhaylo, Poulin-Girard, Anne-Sophie, Rasilla, José Luis, Saint-Antoine, Jonathan, Sarajlic, Mirsad, Segovia, Alex, Seidel, Julia, Ségransan, Damien, Silva, Ana Rita Costa, Srivastava, Avidaan, Stefanov, Atanas K., Mascareño, Alejandro Suárez, Sordet, Michael, Teixeira, Márcio A., Udry, Stéphane, Valencia, Diana, Vallée, Philippe, Vandal, Thomas, Vaulato, Valentina, Wade, Gregg, Wardenier, Joost P., Wehbé, Bachar, Weisserman, Drew, Wevers, Ivan, and Zins, Gérard
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The Near-InfraRed Planet Searcher or NIRPS is a precision radial velocity spectrograph developed through collaborative efforts among laboratories in Switzerland, Canada, Brazil, France, Portugal and Spain. NIRPS extends to the 0.98-1.8 $\mu$m domain of the pioneering HARPS instrument at the La Silla 3.6-m telescope in Chile and it has achieved unparalleled precision, measuring stellar radial velocities in the infrared with accuracy better than 1 m/s. NIRPS can be used either stand-alone or simultaneously with HARPS. Commissioned in late 2022 and early 2023, NIRPS embarked on a 5-year Guaranteed Time Observation (GTO) program in April 2023, spanning 720 observing nights. This program focuses on planetary systems around M dwarfs, encompassing both the immediate solar vicinity and transit follow-ups, alongside transit and emission spectroscopy observations. We highlight NIRPS's current performances and the insights gained during its deployment at the telescope. The lessons learned and successes achieved contribute to the ongoing advancement of precision radial velocity measurements and high spectral fidelity, further solidifying NIRPS' role in the forefront of the field of exoplanets., Comment: Proceeding at the SPIE Astronomical Telescopes + Instrumentation conference [Yokohama,Japan; June 2024]
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- 2024
23. Initial measurement of reactor antineutrino oscillation at SNO+
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Collaboration, SNO, Allega, A., Anderson, M. R., Andringa, S., Askins, M., Auty, D. J., Bacon, A., Baker, J., Barão, F., Barros, N., Bayes, R., Beier, E. W., Bezerra, T. S., Bialek, A., Biller, S. D., Blucher, E., Caden, E., Callaghan, E. J., Chen, M., Cheng, S., Cleveland, B., Cookman, D., Corning, J., Cox, M. A., Dehghani, R., Deloye, J., Depatie, M. M., Di Lodovico, F., Dima, C., Dittmer, J., Dixon, K. H., Esmaeilian, M. S., Falk, E., Fatemighomi, N., Ford, R., Gaur, A., González-Reina, O. I., Gooding, D., Grant, C., Grove, J., Hall, S., Hallin, A. L., Hallman, D., Heintzelman, W. J., Helmer, R. L., Hewitt, C., Howard, V., Hreljac, B., Hu, J., Huang, P., Hunt-Stokes, R., Hussain, S. M. A., Inácio, A. S., Jillings, C. J., Kaluzienski, S., Kaptanoglu, T., Khan, H., Kladnik, J., Klein, J. R., Kormos, L. L., Krar, B., Kraus, C., Krauss, C. B., Kroupová, T., Lake, C., Lebanowski, L., Lefebvre, C., Lozza, V., Luo, M., Maio, A., Manecki, S., Maneira, J., Martin, R. D., McCauley, N., McDonald, A. B., Mills, C., Milton, G., Colina, A. Molina, Morris, D., Morton-Blake, I., Mubasher, M., Naugle, S., Nolan, L. J., O'Keeffe, H. M., Gann, G. D. Orebi, Page, J., Paleshi, K., Parker, W., Paton, J., Peeters, S. J. M., Pickard, L., Quenallata, B., Ravi, P., Reichold, A., Riccetto, S., Rose, J., Rosero, R., Semenec, I., Simms, J., Skensved, P., Smiley, M., Smith, J., Svoboda, R., Tam, B., Tseng, J., Vázquez-Jáuregui, E., Veinot, J. G. C., Virtue, C. J., Ward, M., Weigand, J. J., Wilson, J. R., Wilson, J. D., Wright, A., Yang, S., Yeh, M., Ye, Z., Yu, S., Zhang, Y., Zuber, K., and Zummo, A.
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High Energy Physics - Experiment ,Nuclear Experiment - Abstract
The SNO+ collaboration reports its first spectral analysis of long-baseline reactor antineutrino oscillation using 114 tonne-years of data. Fitting the neutrino oscillation probability to the observed energy spectrum yields constraints on the neutrino mass-squared difference $\Delta m^2_{21}$. In the ranges allowed by previous measurements, the best-fit $\Delta m^2_{21}$ is (8.85$^{+1.10}_{-1.33}$) $\times$ 10$^{-5}$ eV$^2$. This measurement is continuing in the next phases of SNO+ and is expected to surpass the present global precision on $\Delta m^2_{21}$ with about three years of data.
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- 2024
24. Supernova Electron-Neutrino Interactions with Xenon in the nEXO Detector
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nEXO Collaboration, Hedges, S., Kharusi, S. Al, Angelico, E., Brodsky, J. P., Richardson, G., Wilde, S., Amy, A., Anker, A., Arnquist, I. J., Arsenault, P., Atencio, A., Badhrees, I., Bane, J., Belov, V., Bernard, E. P., Bhatta, T., Bolotnikov, A., Breslin, J., Breur, P. A., Brown, E., Brunner, T., Caden, E., Cao, G. F., Cao, L. Q., Cesmecioglu, D., Chambers, E., Chana, B., Charlebois, S. A., Chernyak, D., Chiu, M., Collister, R., Cvitan, M., Dalmasson, J., Daniels, T., Darroch, L., DeVoe, R., di Vacri, M. L., Ding, Y. Y., Dolinski, M. J., Eckert, B., Elbeltagi, M., Elmansali, R., Fabris, L., Fairbank, W., Farine, J., Fatemighomi, N., Foust, B., Fu, Y. S., Gallacher, D., Gallice, N., Gillis, W., Goeldi, D., Gorham, A., Gornea, R., Gratta, G., Guan, Y. D., Hardy, C. A., Heffner, M., Hein, E., Holt, J. D., Hoppe, E. W., House, A., Hunt, W., Iverson, A., Kachru, P., Karelin, A., Keblbeck, D., Kuchenkov, A., Kumar, K. S., Larson, A., Latif, M. B., Leach, K. G., Lenardo, B. G., Leonard, D. S., Lewis, H., Li, G., Li, Z., Licciardi, C., Lindsay, R., MacLellan, R., Majidi, S., Malbrunot, C., Martel-Dion, P., Masbou, J., McMichael, K., Medina-Peregrina, M., Mong, B., Moore, D. C., Nattress, J., Natzke, C. R., Ngwadla, X. E., Ni, K., Nolan, A., Nowicki, S. C., Ondze, J. C. Nzobadila, Orrell, J. L., Ortega, G. S., Overman, C. T., Pagani, L., Smalley, H. Peltz, Perna, A., Piepke, A., Franco, T. Pinto, Pocar, A., Pratte, J. -F., Rasiwala, H., Ray, D., Raymond, K., Rescia, S., Riot, V., Ross, R., Saldanha, R., Sangiorgio, S., Schwartz, S., Sekula, S., Soderstrom, J., Soma, A. K., Spadoni, F., Sun, X. L., Thibado, S., Tidball, A., Totev, T., Triambak, S., Tsang, R. H. M., Tyuka, O. A., van Bruggen, E., Vidal, M., Viel, S., Walent, M., Wang, Q. D., Wang, W., Wang, Y. G., Watts, M., Wehrfritz, M., Wei, W., Wen, L. J., Wichoski, U., Wu, X. M., Xu, H., Yang, H. B., Yang, L., Yu, M., Yvaine, M., Zeldovich, O., and Zhao, J.
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Experiment ,Nuclear Theory - Abstract
Electron-neutrino charged-current interactions with xenon nuclei were modeled in the nEXO neutrinoless double-beta decay detector (~5-tonne, 90% ${}^{136}$Xe, 10% ${}^{134}$Xe) to evaluate its sensitivity to supernova neutrinos. Predictions for event rates and detectable signatures were modeled using the MARLEY event generator. We find good agreement between MARLEY's predictions and existing theoretical calculations of the inclusive cross sections at supernova neutrino energies. The interactions modeled by MARLEY were simulated within the nEXO simulation framework and were run through an example reconstruction algorithm to determine the detector's efficiency for reconstructing these events. The simulated data, incorporating the detector response, were used to study the ability of nEXO to reconstruct the incident electron-neutrino spectrum and these results were extended to a larger xenon detector of the same isotope enrichment. We estimate that nEXO will be able to observe electron-neutrino interactions with xenon from supernovae as far as 5 to 8 kpc from earth, while the ability to reconstruct incident electron-neutrino spectrum parameters from observed interactions in nEXO is limited to closer supernovae., Comment: 17 pages, 16 figures
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- 2024
25. Efficiently manipulating Pauli strings with PauliArray
- Author
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Dion, Maxime, Belabbas, Tania, and Bastien, Nolan
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Quantum Physics - Abstract
Pauli matrices and Pauli strings are widely used in quantum computing. These mathematical objects are useful to describe or manipulate the quantum state of qubits. They offer a convenient basis to express operators and observables used in different problem instances such as molecular simulation and combinatorial optimization. Therefore, it is important to have a well-rounded, versatile and efficient tool to handle a large number of Pauli strings and operators expressed in this basis. This is the objective behind the development of the PauliArray library presented in this work. This library introduces data structures to represent arrays of Pauli strings and operators as well as various methods to modify and combine them. Built using NumPy, PauliArray offers fast operations and the ability to use broadcasting to easily carry out otherwise cumbersome manipulations. Applications to the fermion-to-qubit mapping, to the estimation of expectation values and to the computation of commutators are considered to illustrate how PauliArray can simplify some relevant tasks and accomplish them faster than current libraries., Comment: 10 pages, 4 figures, submitted to IEEE Quantum Week 2024, GitHub repository : https://github.com/algolab-quantique/pauliarray, Documentation : https://algolab-quantique.github.io/pauliarray/index.html
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- 2024
26. Extended spin relaxation times of optically addressed telecom defects in silicon carbide
- Author
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Ahn, Jonghoon, Wicker, Christina, Bitner, Nolan, Solomon, Michael T., Tissot, Benedikt, Burkard, Guido, Dibos, Alan M., Zhang, Jiefei, Heremans, F. Joseph, and Awschalom, David D.
- Subjects
Quantum Physics ,Condensed Matter - Materials Science - Abstract
Optically interfaced solid-state defects are promising candidates for quantum communication technologies. The ideal defect system would feature bright telecom emission, long-lived spin states, and a scalable material platform, simultaneously. Here, we employ one such system, vanadium (V4+) in silicon carbide (SiC), to establish a potential telecom spin-photon interface within a mature semiconductor host. This demonstration of efficient optical spin polarization and readout facilitates all optical measurements of temperature-dependent spin relaxation times (T1). With this technique, we lower the temperature from about 2K to 100 mK to observe a remarkable four-orders-of-magnitude increase in spin T1 from all measured sites, with site-specific values ranging from 57 ms to above 27 s. Furthermore, we identify the underlying relaxation mechanisms, which involve a two-phonon Orbach process, indicating the opportunity for strain-tuning to enable qubit operation at higher temperatures. These results position V4+ in SiC as a prime candidate for scalable quantum nodes in future quantum networks., Comment: 11 pages, 6 figures
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- 2024
27. Sparse maximal update parameterization: A holistic approach to sparse training dynamics
- Author
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Dey, Nolan, Bergsma, Shane, and Hestness, Joel
- Subjects
Computer Science - Machine Learning - Abstract
Several challenges make it difficult for sparse neural networks to compete with dense models. First, setting a large fraction of weights to zero impairs forward and gradient signal propagation. Second, sparse studies often need to test multiple sparsity levels, while also introducing new hyperparameters (HPs), leading to prohibitive tuning costs. Indeed, the standard practice is to re-use the learning HPs originally crafted for dense models. Unfortunately, we show sparse and dense networks do not share the same optimal HPs. Without stable dynamics and effective training recipes, it is costly to test sparsity at scale, which is key to surpassing dense networks and making the business case for sparsity acceleration in hardware. A holistic approach is needed to tackle these challenges and we propose S$\mu$Par as one such approach. S$\mu$Par ensures activations, gradients, and weight updates all scale independently of sparsity level. Further, by reparameterizing the HPs, S$\mu$Par enables the same HP values to be optimal as we vary both sparsity level and model width. HPs can be tuned on small dense networks and transferred to large sparse models, greatly reducing tuning costs. On large-scale language modeling, S$\mu$Par training improves loss by up to 8.2% over the common approach of using the dense model standard parameterization., Comment: 9 pages main text, 11 pages reference and appendix, 11 figures
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- 2024
28. TOI-2447 b / NGTS-29 b: a 69-day Saturn around a Solar analogue
- Author
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Gill, Samuel, Bayliss, Daniel, Ulmer-Moll, Solène, Wheatley, Peter J., Brahm, Rafael, Anderson, David R., Armstrong, David, Apergis, Ioannis, Alves, Douglas R., Burleigh, Matthew R., Butler, R. P., Bouchy, François, Battley, Matthew P., Bryant, Edward M., Bieryla, Allyson, Crane, Jeffrey D., Collins, Karen A., Casewell, Sarah L., Carleo, Ilaria, Claringbold, Alastair B., Dalba, Paul A., Dragomir, Diana, Eigmüller, Philipp, Eberhardt, Jan, Fausnaugh, Michael, Günther, Maximilian N., Grieves, Nolan, Goad, Michael R., Gillen, Edward, Hagelberg, Janis, Hobson, Melissa, Hedges, Christina, Henderson, Beth A., Hawthorn, Faith, Henning, Thomas, Jones, Matías I., Jordán, Andrés, Jenkins, James S., Kunimoto, Michelle, Krenn, Andreas F., Kendall, Alicia, Lendl, Monika, McCormac, James, Moyano, Maximiliano, Torres-Miranda, Pascal, Nielsen, Louise D., Osborn, Ares, Otegi, Jon, Osborn, Hugh, Quinn, Samuel N., Rodriguez, Joseph E., Ramsay, Gavin, Schlecker, Martin, Shectman, Stephen A., Seager, Sara, Tilbrook, Rosanna H., Trifonov, Trifon, Teske, Johanna K., Udry, Stephane, Vines, Jose I., West, Richard R., Wohler, Bill, Winn, Joshua N., Wang, Sharon X., Zhou, George, and Zivave, Tafadzwa
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
Discovering transiting exoplanets with relatively long orbital periods ($>$10 days) is crucial to facilitate the study of cool exoplanet atmospheres ($T_{\rm eq} < 700 K$) and to understand exoplanet formation and inward migration further out than typical transiting exoplanets. In order to discover these longer period transiting exoplanets, long-term photometric and radial velocity campaigns are required. We report the discovery of TOI-2447 b ($=$ NGTS-29b), a Saturn-mass transiting exoplanet orbiting a bright (T=10.0) Solar-type star (T$_{\rm eff}$=5730 K). TOI-2447 b was identified as a transiting exoplanet candidate from a single transit event of 1.3% depth and 7.29 h duration in $TESS$ Sector 31 and a prior transit event from 2017 in NGTS data. Four further transit events were observed with NGTS photometry which revealed an orbital period of P=69.34 days. The transit events establish a radius for TOI-2447 b of $0.865 \pm 0.010\rm R_{\rm J}$, while radial velocity measurements give a mass of $0.386 \pm 0.025 \rm M_{\rm J}$. The equilibrium temperature of the planet is $414$ K, making it much cooler than the majority of $TESS$ planet discoveries. We also detect a transit signal in NGTS data not caused by TOI-2447 b, along with transit timing variations and evidence for a $\sim$150 day signal in radial velocity measurements. It is likely that the system hosts additional planets, but further photometry and radial velocity campaigns will be needed to determine their parameters with confidence. TOI-2447 b/NGTS-29b joins a small but growing population of cool giants that will provide crucial insights into giant planet composition and formation mechanisms., Comment: 16 pages, 12 figures. Accepted for publication in MNRAS
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- 2024
29. Searching for Free-Floating Planets with TESS: A Few Words of Clarification
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Kunimoto, Michelle, DeRocco, William, Smyth, Nolan, and Bryson, Steve
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
We recently described the results of an initial search through TESS Sector 61 for free-floating planets. In this short note, we provide important context for our results and clarify the language used in our initial manuscript to ensure that our intended message is appropriately conveyed., Comment: 2 pages; note regarding arXiv:2404.11666
- Published
- 2024
30. Automated Essay Scoring in Middle School Writing: Understanding Key Predictors of Students' Growth and Comparing Artificial Intelligence- and Teacher-Generated Scores and Feedback
- Author
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Digital Promise, Greene Nolan, Hillary, and Vang, Mai Chou
- Abstract
Providing feedback to students in a sustainable way represents a perennial challenge for secondary teachers of writing. Employing artificial intelligence (AI) tools to give students personalized and immediate feedback holds great promise. Project Topeka offered middle school teachers pre-curated teaching materials, foundational texts and videos, essay prompts, and a platform for students to submit and revise essay drafts with AI-generated scores and feedback. We analyze AI-generated writing scores of 3,233 7th- and 8th-grade students in school year 2021-22 and find that students' growth over time generally was not explained by teachers' (n=35) experience or self-reported instructional approaches. We also find that students' growth increased significantly as their baseline score decreased (i.e., a student with the lowest possible baseline grew more than a student with a medium baseline). Lastly, based on an in-person convening of 16 Topeka teachers, we compared their scores and feedback to AI-generated scores and feedback on the same essays, finding that generally the AI tool was more generous, with differences likely driven by teachers' ability to understand the whole essay's success better than the AI tool.
- Published
- 2023
31. Encouraging Intercultural Interaction by Cultural Specific Learning Design
- Author
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Eimear Nolan, YingFei Héliot, and Bart Rienties
- Abstract
Increased levels of internationalization have led to individuals working in multicultural organizations, a trend that is likely to continue for the foreseeable future. To navigate these environments successfully, more emphasis is being placed on the importance of higher education in preparing and arming the future workforce with the international competencies required to be successful in contemporary organizations. The aim of this research is to shed much needed light on how the learning design of management courses influence how and with whom 263 students learn within two culturally diverse post-graduate management courses. We found that Course B (specific cross-cultural design) significantly and with large effect size increased intercultural interaction over time relative to Course A (generic learning design), whereby qualitative findings confirm substantial differences in lived experiences between the two courses. This highlights that educators need to carefully design intercultural interactions rather than hoping that these will develop naturally over time.
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- 2024
- Full Text
- View/download PDF
32. Unpacking Power: The Role of Critical Reflection in Preschool Internship
- Author
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Charlene Montaño Nolan, Carolyn Brennan, and Tasha Tropp Laman
- Abstract
This study examined the potential role of critical reflection as a tool to support pre-service early childhood teacher interns in understanding and questioning pedagogical choices witnessed in their preschool internships while developing their own socially responsible teaching capacity. This study contributes to the field of critical reflection in teacher education by emphasizing an analysis of power, using Patricia Hill Collins' matrices of power to understand the complexities of systemic injustices and identify potential solutions. The authors conducted an analysis of students' critical reflections, which were completed weekly during their quarter-long preschool internship. The authors found that a critical analytic lens, using power, created intentional space to pause and expand interpretations of unequal and inequitable dynamics within the students' preschool internship experiences, and had the potential to impact their subsequent pedagogical decisions. These findings hold the possibility for teacher preparation programs to bolster students' reflective praxis and seed justice-oriented possibilities in early childhood education.
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- 2024
- Full Text
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33. Moving beyond Reflection and toward Disruption in the Post-Field Context of Mathematics Teacher Education
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Kathleen T. Nolan and Annette H. Bjerke
- Abstract
Prospective teachers bring countless stories of success and failure from different mathematics classrooms to their post-field teacher education courses. These reflective stories often glorify school mathematics classrooms and dominant traditions within, instead of confronting the marginalization of diverse groups in school environments. Mathematics teacher educators have a significant role to play in teaching prospective teachers to reflect critically on their field experiences and, in doing so, create spaces for "disruption" and "disruptive pedagogies." Drawing on critical and equity-based theories applied within the fields of mathematics education and teacher education research, we propose a "disruptive pedagogy" analytical framework that enables us to study the roles and practices of mathematics teacher educators as they conduct their work in these post-field contexts of teacher education. In this paper, we introduce our disruptive pedagogy framework and present the results that followed from using it to analyze data from a research study in which mathematics teacher educators from across Canada and Norway were interviewed. We claim that our analytical framework can be used to identify those disruptive and transformative practices initiated by mathematics teacher educators--practices that are necessary to bring about shifts in inequitable and unjust classroom practices of school mathematics and in becoming a teacher. Unfortunately, however, results reported here point to the need for further shifts and growth toward more explicitly disruptive practices initiated by mathematics teacher educators in the post-field context.
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- 2024
- Full Text
- View/download PDF
34. BETO 2021 peer review : inverse bioproduct design through machine learning and molecular simulation
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Wilson, Nolan
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Machine learning. ,Biological products -- United States. ,Peer review -- United States. - Published
- 2021
35. A global atlas of soil viruses reveals unexplored biodiversity and potential biogeochemical impacts
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Graham, Emily B, Camargo, Antonio Pedro, Wu, Ruonan, Neches, Russell Y, Nolan, Matt, Paez-Espino, David, Kyrpides, Nikos C, Jansson, Janet K, McDermott, Jason E, and Hofmockel, Kirsten S
- Subjects
Microbiology ,Biological Sciences ,Ecology ,Infectious Diseases ,Microbiome ,Aetiology ,2.2 Factors relating to the physical environment ,Infection ,Life Below Water ,Soil Microbiology ,Viruses ,Biodiversity ,Metagenome ,Soil ,Genome ,Viral ,Microbiota ,Carbon ,Metagenomics ,Phylogeny ,Virome ,Bacteria ,Soil Virosphere Consortium ,Medical Microbiology - Abstract
Historically neglected by microbial ecologists, soil viruses are now thought to be critical to global biogeochemical cycles. However, our understanding of their global distribution, activities and interactions with the soil microbiome remains limited. Here we present the Global Soil Virus Atlas, a comprehensive dataset compiled from 2,953 previously sequenced soil metagenomes and composed of 616,935 uncultivated viral genomes and 38,508 unique viral operational taxonomic units. Rarefaction curves from the Global Soil Virus Atlas indicate that most soil viral diversity remains unexplored, further underscored by high spatial turnover and low rates of shared viral operational taxonomic units across samples. By examining genes associated with biogeochemical functions, we also demonstrate the viral potential to impact soil carbon and nutrient cycling. This study represents an extensive characterization of soil viral diversity and provides a foundation for developing testable hypotheses regarding the role of the virosphere in the soil microbiome and global biogeochemistry.
- Published
- 2024
36. Phylogeny, morphology, virulence, ecology, and host range of Ordospora pajunii (Ordosporidae), a microsporidian symbiont of Daphnia spp.
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Dziuba, Marcin K, McIntire, Kristina M, Seto, Kensuke, Davenport, Elizabeth S, Rogalski, Mary A, Gowler, Camden D, Baird, Emma, Vaandrager, Megan, Huerta, Cristian, Jaye, Riley, Corcoran, Fiona E, Withrow, Alicia, Ahrendt, Steven, Salamov, Asaf, Nolan, Matt, Tejomurthula, Sravanthi, Barry, Kerrie, Grigoriev, Igor V, James, Timothy Y, and Duffy, Meghan A
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Microbiology ,Medical Microbiology ,Biomedical and Clinical Sciences ,Biological Sciences ,Infectious Diseases ,Genetics ,2.1 Biological and endogenous factors ,2.2 Factors relating to the physical environment ,Infection ,Animals ,Daphnia ,Symbiosis ,Host Specificity ,Phylogeny ,Virulence ,Microsporidia ,Microsporidia ,Unclassified ,microsporidia ,mutualism-parasitism continuum ,symbiosis ,pathogen ,zooplankton ,Biochemistry and cell biology ,Medical microbiology - Abstract
The impacts of microsporidia on host individuals are frequently subtle and can be context dependent. A key example of the latter comes from a recently discovered microsporidian symbiont of Daphnia, the net impact of which was found to shift from negative to positive based on environmental context. Given this, we hypothesized low baseline virulence of the microsporidian; here, we investigated the impact of infection on hosts in controlled conditions and the absence of other stressors. We also investigated its phylogenetic position, ecology, and host range. The genetic data indicate that the symbiont is Ordospora pajunii, a newly described microsporidian parasite of Daphnia. We show that O. pajunii infection damages the gut, causing infected epithelial cells to lose microvilli and then rupture. The prevalence of this microsporidian could be high (up to 100% in the lab and 77% of adults in the field). Its overall virulence was low in most cases, but some genotypes suffered reduced survival and/or reproduction. Susceptibility and virulence were strongly host-genotype dependent. We found that North American O. pajunii were able to infect multiple Daphnia species, including the European species Daphnia longispina, as well as Ceriodaphnia spp. Given the low, often undetectable virulence of this microsporidian and potentially far-reaching consequences of infections for the host when interacting with other pathogens or food, this Daphnia-O. pajunii symbiosis emerges as a valuable system for studying the mechanisms of context-dependent shifts between mutualism and parasitism, as well as for understanding how symbionts might alter host interactions with resources.ImportanceThe net outcome of symbiosis depends on the costs and benefits to each partner. Those can be context dependent, driving the potential for an interaction to change between parasitism and mutualism. Understanding the baseline fitness impact in an interaction can help us understand those shifts; for an organism that is generally parasitic, it should be easier for it to become a mutualist if its baseline virulence is relatively low. Recently, a microsporidian was found to become beneficial to its Daphnia hosts in certain ecological contexts, but little was known about the symbiont (including its species identity). Here, we identify it as the microsporidium Ordospora pajunii. Despite the parasitic nature of microsporidia, we found O. pajunii to be, at most, mildly virulent; this helps explain why it can shift toward mutualism in certain ecological contexts and helps establish O. pajunii is a valuable model for investigating shifts along the mutualism-parasitism continuum.
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- 2024
37. Assessing the Fractional Curve for Proper Management of Adult Degenerative Scoliosis.
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Ransom, Seth, Pennington, Zach, Brown, Nolan, Shahrestani, Shane, Ryvlin, Jessica, Shoustari, Ali, Hagen, John, Mikula, Anthony, Lakomkin, Nikita, Diaz-Aguilar, Luis, Elder, Benjamin, Osorio, Joseph, and Pham, Martin
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Adult degenerative scoliosis ,Adult spinal deformity ,Fractional curve ,Neurosurgery ,Radiography ,Spine surgery - Abstract
Adult degenerative scoliosis (ADS) is a coronal plane deformity often accompanied by sagittal plane malalignment. Surgical correction may involve the major and/or distally-located fractional curves (FCs). Correction of the FC has been increasingly recognized as key to ameliorating radicular pain localized to the FC levels. The present study aims to summarize the literature on the rationale for FC correction in ADS. Three databases were systematically reviewed to identify all primary studies reporting the rationale for correcting the FC in ADS. Articles were included if they were English full-text studies with primary data from ADS ( ≥ 18 years old) patients. Seventy-four articles were identified, of which 12 were included after full-text review. Findings suggest FC correction with long-segment fusion terminating at L5 increases the risk of distal junctional degeneration as compared to constructs instrumenting the sacrum. Additionally, circumferential fusion offers greater FC correction, lower reoperation risk, and shorter construct length. Minimally invasive surgery (MIS) techniques may offer effective radiographic correction and improve leg pain associated with foraminal stenosis on the FC concavity, though experiences are limited. Open surgery may be necessary to achieve adequate correction of severe, highly rigid deformities. Current data support major curve correction in ASD where the FC concavity and truncal shift are concordant, suggesting that the FC contributes to the patients overall deformity. Circumferential fusion and the use of kickstand rods can improve correction and enhance the stability and durability of long constructs. Last, MIS techniques show promise for milder deformities but require further investigation.
- Published
- 2024
38. The EV antibody database: An interactive database of curated antibodies for extracellular vesicle and nanoparticle research.
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Morey, Amber, Ng, Martin, Spanos, Michail, Zhang, Piyan, Xu, Tuoye, Cheung, Willi, Chatterjee, Emeli, Gokulnath, Priyanka, Carnel-Amar, Natacha, Soares Chiaretti, Ana, Nelson, Collin, George, Jubin, Luo, Michelle, Chakraborty, Abhik, Perucci, Luiza, Jones, Jennifer, Hoff, Peter, Franklin, Jeffrey, Raffai, Robert, Das, Saumya, Routenberg, David, Nolan, John, Charest, Al, Laurent, Louise, and Alexander, Roger
- Subjects
Antibodies ,Antibody database ,Exosomes ,Extracellular vesicles ,Nanoparticles - Abstract
Antibodies are critical tools for research into extracellular vesicles (EVs) and other extracellular nanoparticles (ENPs), where they can be used for their identification, characterization, and isolation. However, the lack of a centralized antibody platform where researchers can share validation results thus minimizing wasted personnel time and reagents, has been a significant obstacle. Moreover, because the performance of antibodies varies among assay types and conditions, detailed information on assay variables and protocols is also of value. To facilitate sharing of results on antibodies that are relevant to EV/ENP research, the EV Antibody Database has been developed by the investigators of the Extracellular RNA Communication Consortium (ERCC). Hosted by the ExRNA Portal (https://exrna.org/resources/evabdb/), this interactive database aggregates and shares results from antibodies that have been tested by research groups in the EV/ENP field. Currently, the EV Antibody Database includes modules for antibodies tested for western Blot, EV Flow Cytometry, and EV Sandwich Assays, and holds 110 records contributed by 6 laboratories from the ERCC. Detailed information on antibody sources, assay conditions, and results is provided, including negative results. We encourage ongoing expert input and community feedback to enhance the databases utility, making it a valuable resource for comprehensive validation data on antibodies and protocols in EV biology.
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- 2024
39. Seven Years of the Transcarotid Artery Revascularization Surveillance Project, Comparison to Transfemoral Stenting and Endarterectomy
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Straus, Sabrina, Yadavalli, Sai Divya, Allievi, Sara, Sanders, Andrew P, Malas, Mahmoud, Wang, Grace J, Kashyap, Vikram, Cronenwett, Jack, Motaganahalli, Raghu L, Nolan, Brian, Eldrup-Jorgensen, Jens, and Schermerhorn, Marc L
- Subjects
Biomedical and Clinical Sciences ,Cardiovascular Medicine and Haematology ,Clinical Sciences ,Good Health and Well Being ,Medical and Health Sciences ,Cardiovascular System & Hematology ,Cardiovascular medicine and haematology ,Clinical sciences - Published
- 2024
40. Similar enzymatic functions in distinct bioluminescence systems: evolutionary recruitment of sulfotransferases in ostracod light organs.
- Author
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Lau, Emily, Goodheart, Jessica, Anderson, Nolan, Liu, Vannie, Mukherjee, Arnab, and Oakley, Todd
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bioluminescence ,complex traits ,convergent evolution ,gene expression ,parallel evolution ,sulfotransferase ,Animals ,Sulfotransferases ,Crustacea ,Phylogeny ,Evolution ,Molecular ,Luminescence - Abstract
Genes from ancient families are sometimes involved in the convergent evolutionary origins of similar traits, even across vast phylogenetic distances. Sulfotransferases are an ancient family of enzymes that transfer sulfate from a donor to a wide variety of substrates, including probable roles in some bioluminescence systems. Here, we demonstrate multiple sulfotransferases, highly expressed in light organs of the bioluminescent ostracod Vargula tsujii, transfer sulfate in vitro to the luciferin substrate, vargulin. We find luciferin sulfotransferases (LSTs) of ostracods are not orthologous to known LSTs of fireflies or sea pansies; animals with distinct and convergently evolved bioluminescence systems compared to ostracods. Therefore, distantly related sulfotransferases were independently recruited at least three times, leading to parallel evolution of luciferin metabolism in three highly diverged organisms. Reuse of homologous genes is surprising in these bioluminescence systems because the other components, including luciferins and luciferases, are completely distinct. Whether convergently evolved traits incorporate ancient genes with similar functions or instead use distinct, often newer, genes may be constrained by how many genetic solutions exist for a particular function. When fewer solutions exist, as in genetic sulfation of small molecules, evolution may be more constrained to use the same genes time and again.
- Published
- 2024
41. Prepectoral versus Subpectoral Breast Reconstruction after Nipple-sparing Mastectomy: A Systematic Review and Meta-Analysis.
- Author
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Nolan, Ian, Farajzadeh, Matthew, Bekisz, Jonathan, Boyd, Carter, Gibson, Ella, and Salibian, Ara
- Abstract
BACKGROUND: Implant-based breast reconstruction after nipple-sparing mastectomy (NSM) presents unique benefits and challenges. The literature has compared outcomes among total submuscular (TSM), dual-plane (DP), and prepectoral (PP) planes; however, a dedicated meta-analysis relevant to NSM is lacking. METHODS: We conducted a systematic review of studies on immediate breast reconstruction after NSM using TSM, DP, or PP prosthesis placement in PubMed, Embase, and Cochrane databases. In total, 1317 unique articles were identified, of which 49 were included in the systematic review and six met inclusion criteria for meta-analysis. Pooled descriptive outcomes were analyzed for each cohort for all 49 studies. Fixed-effects meta-analytic methods were used to compare PP with subpectoral (TSM and DP) reconstructions. RESULTS: A total of 1432 TSM, 1546 DP, and 1668 PP reconstructions were identified for descriptive analysis. Demographics were similar between cohorts. Pooled descriptive outcomes demonstrated overall similar rates of reconstructive failure (3.3%-5.1%) as well as capsular contracture (0%-3.9%) among cohorts. Fixed-effects meta-analysis of six comparative studies demonstrated a significantly lower rate of mastectomy flap necrosis in the PP cohort compared with the subpectoral cohort (relative risk 0.24, 95% confidence interval [0.08-0.74]). All other consistently reported outcomes, including, hematoma, seroma, infection, mastectomy flap necrosis, nipple -areola complex necrosis, and explantation were comparable. CONCLUSIONS: A systematic review of the literature and meta-analysis demonstrated the safety of immediate prepectoral breast reconstruction after NSM, compared with submuscular techniques. Submuscular reconstruction had a higher risk of mastectomy flap necrosis, though potentially influenced by selection bias.
- Published
- 2024
42. Patient-specific rods in adult spinal deformity: a systematic review.
- Author
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Picton, Bryce, Stone, Lauren, Liang, Jason, Solomon, Sean, Brown, Nolan, Luzzi, Sophia, Osorio, Joseph, and Pham, Martin
- Subjects
Machine learning ,Operative planning ,Patient-specific rods ,Spinal deformity ,Humans ,Adult ,Lordosis ,Treatment Outcome ,Spinal Curvatures ,Spine ,Spinal Fusion - Abstract
PURPOSE: The purpose of this review was to evaluate the effectiveness of patient-specific rods for adult spinal deformity. METHODS: A systematic review of the literature was performed through an electronic search of the PubMed, Scopus, and Web of Science databases. Human studies between 2012 and 2023 were included. Sample size, sagittal vertical axis (SVA), pelvic incidence-lumbar lordosis (PI-LL), pelvic tilt (PT), operation time, blood loss, follow-up duration, and complications were recorded for each study when available. RESULTS: Seven studies with a total of 304 adult spinal deformity patients of various etiologies were included. All studies reported SVA, and PT; two studies did not report PI-LL. Four studies reported planned radiographic outcomes. Two found a significant association between preoperative plan and postoperative outcome in all three outcomes. One found a significant association for PI-LL alone. The fourth found no significant associations. SVA improved in six of seven studies, PI-LL improved in all five, and three of seven studies found improved postoperative PT. Significance of these results varied greatly by study. CONCLUSION: Preliminary evidence suggests potential benefits of PSRs in achieving optimal spino-pelvic parameters in ASD surgery. Nevertheless, conclusions regarding the superiority of PSRs over traditional rods must be judiciously drawn, given the heterogeneity of patients and study methodologies, potential confounding variables, and the absence of robust randomized controlled trials. Future investigations should concentrate on enhancing preoperative planning, standardizing surgical methodologies, isolating specific patient subgroups, and head-to-head comparisons with traditional rods to fully elucidate the impact of PSRs in ASD surgery.
- Published
- 2024
43. Young Stellar Objects in NGC 346: A JWST NIRCam/MIRI Imaging Survey
- Author
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Habel, Nolan, Nally, Conor, Lenkic, Laura, Meixner, Margaret, De Marchi, Guido, Kavanagh, Patrick J., Fahrion, Katja, Nayak, Omnarayani, Hirschauer, Alec S., Jones, Olivia C., Biazzo, Katia, Brandl, Bernhard R., Jaspers, Jeroen, Pontoppidan, Klaus M., Robberto, Massimo, Rogers, Ciaran, Sabbi, Elena, Sargent, B. A., Soderblom, David R., and Zeidler, Peter
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
We present a JWST imaging survey with NIRCam and MIRI of NGC 346, the brightest star-forming region in the Small Magellanic Cloud (SMC). By combining aperture and point spread function (PSF) photometry of eleven wavelength bands across these two instruments, we have detected more than 200,000 unique sources. Using near-infrared (IR) color analysis, we observe various evolved and young populations, including 196 young stellar objects (YSOs) and pre-main sequence stars suitable for forthcoming spectroscopic studies. We expand upon this work, creating mid-IR color-magnitude diagrams and determining color cuts to identify 833 reddened sources which are YSO candidates. We observe that these candidate sources are spatially associated with regions of dusty, filamentary nebulosity. Furthermore, we fit model YSO spectral energy distributions (SEDs) to a selection of sources with detections across all of our MIRI bands. We classify with a high degree of confidence 23 YSOs in this sample and estimate their radii, bolometric temperatures, luminosities, and masses. We detect YSOs approaching 1 solar mass, the lowest-mass extragalactic YSOs confirmed to date.
- Published
- 2024
44. Searching for Free-Floating Planets with TESS: I. Discovery of a First Terrestrial-Mass Candidate
- Author
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Kunimoto, Michelle, DeRocco, William, Smyth, Nolan, and Bryson, Steve
- Subjects
Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Though free-floating planets (FFPs) that have been ejected from their natal star systems may outpopulate their bound counterparts in the terrestrial-mass range, they remain one of the least explored exoplanet demographics. Due to their negligible electromagnetic emission at all wavelengths, the only observational technique able to detect these worlds is gravitational microlensing. Microlensing by terrestrial-mass FFPs induces rare, short-duration magnifications of background stars, requiring high-cadence, wide-field surveys to detect these events. The Transiting Exoplanet Survey Satellite (TESS), though designed to detect close-bound exoplanets via the transit technique, boasts a cadence as short as 200 seconds and has monitored hundreds of millions of stars, making it well-suited to search for short-duration microlensing events as well. We have used existing data products from the TESS Quick-Look Pipeline (QLP) to perform a preliminary search for FFP microlensing candidates in 1.3 million light curves from TESS Sector 61. We find one compelling candidate associated with TIC-107150013, a source star at $d_s = 3.194$ kpc. The event has a duration $t_E = 0.074^{+0.002}_{-0.002}$ days and shows prominent finite-source features ($\rho = 4.55^{+0.08}_{-0.07}$), making it consistent with an FFP in the terrestrial-mass range. This exciting result indicates that our ongoing search through all TESS sectors has the opportunity to shed new light on this enigmatic population of worlds., Comment: 10 pages, 7 figures, submitted to MNRAS
- Published
- 2024
45. Global Contrastive Training for Multimodal Electronic Health Records with Language Supervision
- Author
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Ma, Yingbo, Kolla, Suraj, Hu, Zhenhong, Kaliraman, Dhruv, Nolan, Victoria, Guan, Ziyuan, Ren, Yuanfang, Armfield, Brooke, Ozrazgat-Baslanti, Tezcan, Balch, Jeremy A., Loftus, Tyler J., Rashidi, Parisa, Bihorac, Azra, and Shickel, Benjamin
- Subjects
Computer Science - Machine Learning ,Computer Science - Computation and Language - Abstract
Modern electronic health records (EHRs) hold immense promise in tracking personalized patient health trajectories through sequential deep learning, owing to their extensive breadth, scale, and temporal granularity. Nonetheless, how to effectively leverage multiple modalities from EHRs poses significant challenges, given its complex characteristics such as high dimensionality, multimodality, sparsity, varied recording frequencies, and temporal irregularities. To this end, this paper introduces a novel multimodal contrastive learning framework, specifically focusing on medical time series and clinical notes. To tackle the challenge of sparsity and irregular time intervals in medical time series, the framework integrates temporal cross-attention transformers with a dynamic embedding and tokenization scheme for learning multimodal feature representations. To harness the interconnected relationships between medical time series and clinical notes, the framework equips a global contrastive loss, aligning a patient's multimodal feature representations with the corresponding discharge summaries. Since discharge summaries uniquely pertain to individual patients and represent a holistic view of the patient's hospital stay, machine learning models are led to learn discriminative multimodal features via global contrasting. Extensive experiments with a real-world EHR dataset demonstrated that our framework outperformed state-of-the-art approaches on the exemplar task of predicting the occurrence of nine postoperative complications for more than 120,000 major inpatient surgeries using multimodal data from UF health system split among three hospitals (UF Health Gainesville, UF Health Jacksonville, and UF Health Jacksonville-North)., Comment: 12 pages, 3 figures. arXiv admin note: text overlap with arXiv:2403.04012
- Published
- 2024
46. Singular solutions for complex second order elliptic equations and their application to time-harmonic diffuse optical tomography
- Author
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Curran, Jason, Gaburro, Romina, and Nolan, Clifford
- Subjects
Mathematics - Analysis of PDEs - Abstract
We construct singular solutions of a complex elliptic equation of second order, having an isolated singularity of any order. In particular, we extend results obtained for the real partial differential equation in divergence form by Alessandrini in 1990. Our solutions can be applied to the determination of the optical properties of an anisotropic medium in time-harmonic Diffuse Optical Tomography (DOT).
- Published
- 2024
47. Using Machine Learning to Forecast Market Direction with Efficient Frontier Coefficients
- Author
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Alexander, Nolan and Scherer, William
- Subjects
Quantitative Finance - Portfolio Management - Abstract
We propose a novel method to improve estimation of asset returns for portfolio optimization. This approach first performs a monthly directional market forecast using an online decision tree. The decision tree is trained on a novel set of features engineered from portfolio theory: the efficient frontier functional coefficients. Efficient frontiers can be decomposed to their functional form, a square-root second-order polynomial, and the coefficients of this function captures the information of all the constituents that compose the market in the current time period. To make these forecasts actionable, these directional forecasts are integrated to a portfolio optimization framework using expected returns conditional on the market forecast as an estimate for the return vector. This conditional expectation is calculated using the inverse Mills ratio, and the Capital Asset Pricing Model is used to translate the market forecast to individual asset forecasts. This novel method outperforms baseline portfolios, as well as other feature sets including technical indicators and the Fama-French factors. To empirically validate the proposed model, we employ a set of market sector ETFs.
- Published
- 2024
48. Constraints on Primordial Black Holes from $N$-body simulations of the Eridanus II Stellar Cluster
- Author
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Koulen, Julia Monika, Profumo, Stefano, and Smyth, Nolan
- Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics ,High Energy Physics - Phenomenology - Abstract
The tidal disruption of old, compact stellar structures provides strong constraints on macroscopic dark matter candidates such as primordial black holes. In view of recent, new observational data on the Eridanus II dwarf galaxy and on its central stellar cluster, we employ, for the first time, $N$-body simulations to assess the impact of compact massive dark matter candidates on the gravitational stability of the cluster. We find evidence that such candidates must be lighter than about one solar mass if they constitute the totality of the dark matter. We additionally derive robust constraints on the fraction of the dark matter in macroscopic objects as a function of mass, by suitably modeling the remainder of the dark matter as standard fluid-like cold dark matter., Comment: 17 pages, 6 figures
- Published
- 2024
49. Imaging of I Zw 18 by JWST. I. Strategy and First Results of Dusty Stellar Populations
- Author
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Hirschauer, Alec S., Crouzet, Nicolas, Habel, Nolan, Lenkić, Laura, Nally, Conor, Jones, Olivia C., Bortolini, Giacomo, Boyer, Martha L., Meixner, Kay Justtanont Margaret, Östlin, Göran, Wright, Gillian S., Azzollini, Ruyman, Blommaert, Joris A. D. L., Brandl, Bernhard, Decin, Leen, Nayak, Omnarayani, Royer, Pierre, Sargent, B. A., and van der Werf, Paul
- Subjects
Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
We present a JWST imaging survey of I Zw 18, the archetypal extremely metal-poor, star-forming (SF), blue compact dwarf galaxy. With an oxygen abundance of only $\sim$3% $Z_{\odot}$, it is among the lowest-metallicity systems known in the local Universe, and is, therefore, an excellent accessible analog for the galactic building blocks which existed at early epochs of ionization and star formation. These JWST data provide a comprehensive infrared (IR) view of I Zw 18 with eight filters utilizing both Near Infrared Camera (F115W, F200W, F356W, and F444W) and Mid-Infrared Instrument (F770W, F1000W, F1500W, and F1800W) photometry, which we have used to identify key stellar populations that are bright in the near- and mid-IR. These data allow for a better understanding of the origins of dust and dust-production mechanisms in metal-poor environments by characterizing the population of massive, evolved stars in the red supergiant (RSG) and asymptotic giant branch (AGB) phases. In addition, it enables the identification of the brightest dust-enshrouded young stellar objects (YSOs), which provide insight into the formation of massive stars at extremely low metallicities typical of the very early Universe. This paper provides an overview of the observational strategy and data processing, and presents first science results, including identifications of dusty AGB, RSG, and bright YSO candidates. These first results assess the scientific quality of JWST data and provide a guide for obtaining and interpreting future observations of the dusty and evolved stars inhabiting compact dwarf SF galaxies in the local Universe., Comment: Accepted for publication in The Astronomical Journal; 25 pages, 14 figures, 4 tables
- Published
- 2024
- Full Text
- View/download PDF
50. Temporal Cross-Attention for Dynamic Embedding and Tokenization of Multimodal Electronic Health Records
- Author
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Ma, Yingbo, Kolla, Suraj, Kaliraman, Dhruv, Nolan, Victoria, Hu, Zhenhong, Guan, Ziyuan, Ren, Yuanfang, Armfield, Brooke, Ozrazgat-Baslanti, Tezcan, Loftus, Tyler J., Rashidi, Parisa, Bihorac, Azra, and Shickel, Benjamin
- Subjects
Computer Science - Machine Learning - Abstract
The breadth, scale, and temporal granularity of modern electronic health records (EHR) systems offers great potential for estimating personalized and contextual patient health trajectories using sequential deep learning. However, learning useful representations of EHR data is challenging due to its high dimensionality, sparsity, multimodality, irregular and variable-specific recording frequency, and timestamp duplication when multiple measurements are recorded simultaneously. Although recent efforts to fuse structured EHR and unstructured clinical notes suggest the potential for more accurate prediction of clinical outcomes, less focus has been placed on EHR embedding approaches that directly address temporal EHR challenges by learning time-aware representations from multimodal patient time series. In this paper, we introduce a dynamic embedding and tokenization framework for precise representation of multimodal clinical time series that combines novel methods for encoding time and sequential position with temporal cross-attention. Our embedding and tokenization framework, when integrated into a multitask transformer classifier with sliding window attention, outperformed baseline approaches on the exemplar task of predicting the occurrence of nine postoperative complications of more than 120,000 major inpatient surgeries using multimodal data from three hospitals and two academic health centers in the United States., Comment: ICLR 2024 Workshop on Learning From Time Series for Health. 10 pages, 3 figures
- Published
- 2024
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