• A 1720-nm ring-cavity Tm-doped fiber laser with optimized output coupling

      Zhang, L.; Zhang, J.; Sheng, Q.; Sun, S.; Shi, C.; Fu, S.; Bai, X.; Shi, W.; Yao, J.; College of Optical Sciences, University of Arizona (SPIE, 2021)
      We have demonstrated an efficient 1720-nm all-fiber laser with ring-cavity configuration based on commercial Tmdoped silica fiber and 1570-nm in-band pump source. The rate equation model was built up to analyze the laser performance of Tm-doped fiber, which exhibits strong absorption in 1.7-µm region. The results show that efficient laser operation can be achieved through the optimization of output coupling and the length of Tm-doped fiber. By using homemade couplers, we experimentally achieved 2.36-W laser output power under 6-W launched pump power. The slope efficiency with respect to the absorbed pump power and optical efficiency were 50.2% and 39.3%, respectively. Due to the employment of ring resonator, a narrow laser linewidth of ~4 GHz at maximum output power was observed. © 2021 SPIE.
    • A BERT-based One-Pass Multi-Task Model for Clinical Temporal Relation Extraction

      Lin, Chen; Miller, Timothy; Dligach, Dmitriy; Sadeque, Farig; Bethard, Steven; Savova, Guergana; Univ Arizona (ASSOC COMPUTATIONAL LINGUISTICS-ACL, 2020-07)
      Recently BERT has achieved a state-of-the-art performance in temporal relation extraction from clinical Electronic Medical Records text. However, the current approach is inefficient as it requires multiple passes through each input sequence. We extend a recently-proposed one-pass model for relation classification to a one-pass model for relation extraction. We augment this framework by introducing global embeddings to help with long-distance relation inference, and by multi-task learning to increase model performance and generalizability. Our proposed model produces results on par with the state-of-the-art in temporal relation extraction on the THYME corpus and is much "greener" in computational cost.
    • A Bibliometric Analysis and Visualization of the Top-Cited Publications in Mild Traumatic Brain Injury

      Shi, J.; Du, X.; Cavagnaro, M.J.; Li, N.; College of Medicine, University of Arizona (Frontiers Media S.A., 2021)
      Background: For measuring their impact in scientific research, the citation count of the publications is used in the bibliometric analysis, though still in the bibliometric analysis, there is no comprehensive summary of mild traumatic brain injury (mTBI) research. This article intends to provide the physicians and the neuroscientists with a reference guide to assess the most influential publications written on this subject through a macroscopic view of the research activities on mTBI. Methods: The database of the Web of Science was used to compile the 100 top-ranking publications on mTBI. The selected publications were evaluated on the basis of the several categorizations including the type of the publications, number of citations, country of origin, and year of publication. Results: Between 1946 and 2020, the 13,040 publications that were published were included in the database. The least cited publications received 274 citations, while the most cited received 1,748. Altogether, 71 publications were from the USA while 29 were from other countries. Among all the institutions, the University of Pittsburgh Medical Center led the list with six publications. Around 100 papers, mostly on the clinical studies in the categories of neurology and neurosciences, were published in 54 different journals. Conclusions: This study provides both a transverse section summary and historical retrospect for the clinical advances of mTBI, and the publications of important observations that contributed a significant impact on the treatment and prevention of mTBI had been identified. © Copyright © 2021 Shi, Du, Cavagnaro and Li.
    • A bioinformatic analysis of the inhibin-betaglycan-endoglin/CD105 network reveals prognostic value in multiple solid tumors

      Listik, E.; Horst, B.; Choi, A.S.; Lee, N.Y.; Győrffy, B.; Mythreye, K.; Division of Pharmacology, Chemistry and Biochemistry, College of Medicine, University of Arizona (Public Library of Science, 2021)
      Inhibins and activins are dimeric ligands belonging to the TGFβ superfamily with emergent roles in cancer. Inhibins contain an α-subunit (INHA) and a β-subunit (either INHBA or INHBB), while activins are mainly homodimers of either βA (INHBA) or βB (INHBB) subunits. Inhibins are biomarkers in a subset of cancers and utilize the coreceptors betaglycan (TGFBR3) and endoglin (ENG) for physiological or pathological outcomes. Given the array of prior reports on inhibin, activin and the coreceptors in cancer, this study aims to provide a comprehensive analysis, assessing their functional prognostic potential in cancer using a bioinformatics approach. We identify cancer cell lines and cancer types most dependent and impacted, which included p53 mutated breast and ovarian cancers and lung adenocarcinomas. Moreover, INHA itself was dependent on TGFBR3 and ENG/CD105 in multiple cancer types. INHA, INHBA, TGFBR3, and ENG also predicted patients’ response to anthracycline and taxane therapy in luminal A breast cancers. We also obtained a gene signature model that could accurately classify 96.7% of the cases based on outcomes. Lastly, we cross-compared gene correlations revealing INHA dependency to TGFBR3 or ENG influencing different pathways themselves. These results suggest that inhibins are particularly important in a subset of cancers depending on the coreceptor TGFBR3 and ENG and are of substantial prognostic value, thereby warranting further investigation. © 2021 Listik et al.
    • A Brighter Future: The Effect of Social Class on Responses to Future Debt

      Schmitt, Harrison J.; Keefer, Lucas A.; Sullivan, Daniel; Stewart, Sheridan; Young, Isaac F.; Univ Arizona, Dept Psychol (PSYCHOPEN, 2020-07)
      The present study serves as an exploratory investigation of the role of social class in responses to the threat of future debt. Previous work has shown that individuals of high and low subjective social class differ in the ways that they respond to a broad range of threats and uncertainties about the future. Across three studies, we found that lower social class individuals expect more future debt and suffer greater attendant stress than higher class individuals (Study 1). We found that experimental manipulations of debt salience increased stress for lower class and not for higher class individuals (Studies 2-3). Likewise, we found that higher class individuals experienced higher affect balance and perceptions of personal control when the possibility of future debt was made salient, specifically as a function of decreased fatalism about future debt (Study 3). These three studies reveal yet another situation in which individuals of lower and higher social class respond differently to threat, and serve as an important step toward understanding the psychological ramifications of rising debt in the United States.
    • A case of leiomyosarcoma of the common femoral artery

      Nguyen, D.; Leon, L.R.; Pacanowski, J.P.; Berman, S.S.; Pima Heart and Vascular, Section of Vascular Surgery, The University of Arizona (Society for Vascular Surgery, 2021)
      Leiomyosarcomas are rare malignant tumors of smooth muscle cell origin with those originating from blood vessels accounting for <1%. We report the unusual case of a leiomyosarcoma originating in the wall of the common femoral artery, highlighting the management decisions for vascular tumors and providing a brief literature review for these unusual malignancies. © 2021 The Authors
    • A Closer Look at Two of the Most Luminous Quasars in the Universe

      Schindler, J.-T.; Fan, X.; Novak, M.; Venemans, B.; Walter, F.; Wang, F.; Yang, J.; Yue, M.; Bañados, E.; Huang, Y.-H.; et al. (IOP Publishing Ltd, 2020)
      Ultraluminous quasars (M 1450 ≤ -29) provide us with a rare view into the nature of the most massive and most rapidly accreting supermassive black holes (SMBHs). Following the discovery of two of these extreme sources, J0341+1720 (M 1450 = -29.56, z = 3.71) and J2125-1719 (M 1450 = -29.39, z = 3.90), in the Extremely Luminous Quasar Survey (ELQS) and its extension to the Pan-STARRS 1 footprint (PS-ELQS), we herein present an analysis of their rest-frame UV to optical spectroscopy. Both quasars harbor very massive SMBHs with M BH =6.73 - 0.83+0.75 × 10 9, M ⊙ and M BH = 5.45 -0.55 +0.60 × 10 9, M ⊙, respectively, showing evidence of accretion above the Eddington limit ( and ). NOEMA 3 millimeter observations of J0341+1720 reveal a highly star-forming (SFR ≈ 1500 M o˙ yr-1), ultraluminous infrared galaxy (L IR ≈ 1.0 1013 L o˙) host, which, based on an estimate of its dynamical mass, is only ∼30 times more massive than the SMBH it harbors at its center. As examples of luminous super-Eddington accretion, these two quasars provide support for theories that explain the existence of billion solar mass SMBHs ∼700 million years after the Big Bang by moderate super-Eddington growth from standard SMBH seeds. © 2020. The American Astronomical Society. All rights reserved.
    • A co-registered multimodal imaging system for reflectance, multiphoton, and optical coherence microscopy

      Vega, D.; Barton, J.K.; Galvez, D.; Santaniello, S.P.; Adams, Z.; Pham, N.Y.; Kiekens, K.; Cordova, R.; Montague, J.; College of Optical Sciences, University of Arizona; et al. (SPIE, 2021)
      Multimodal imaging is an advantageous method to increase the accuracy of disease classification. As an example, we and others have shown that optical coherence tomography images and fluorescence spectroscopy contain complementary information that can increase the sensitivity and specificity for cancer detection. A common challenge in multimodal imaging is image co-registration. The different images are often taken with separate imaging setups, making it challenging to precisely image the same tissue area or co-register the images computationally. To solve this problem, we have developed a co-registered multimodal imaging system that images the same tissue location with reflectance, multi-photon, and optical coherence microscopy. The co-registration mechanism is a dual-clad fiber that integrates with a scanning microscope or scanning endoscope, collecting all three signals using the same optical path. In the current implementation, optical coherence tomography utilizes a 1300 nm super luminescent diode, multi-photon signals are excited by a custom femtosecond 1400 nm fiber laser producing two-and three-photon signals in the 460-900 nm band, and reflectance imaging operates at 561 nm. The system separates the different signals using fiber wavelength division multiplexers, a dual-clad fiber coupler, and dichroic mirrors to deliver the different signals to the corresponding detector. This wavelength selection enables the system to work passively, meaning that there is no need for devices such as filter wheels. Using the scanning microscope configuration, we have obtained multimodal images of ex-vivo ovine ovary tissue. © 2021 SPIE.
    • A community-maintained standard library of population genetic models

      Adrion, Jeffrey R.; Cole, Christopher B.; Dukler, Noah; Galloway, Jared G.; Gladstein, Ariella L.; Gower, Graham; Kyriazis, Christopher C.; Ragsdale, Aaron P.; Tsambos, Georgia; Baumdicker, Franz; et al. (ELIFE SCIENCES PUBLICATIONS LTD, 2020-06)
      The explosion in population genomic data demands ever more complex modes of analysis, and increasingly, these analyses depend on sophisticated simulations. Recent advances in population genetic simulation have made it possible to simulate large and complex models, but specifying such models for a particular simulation engine remains a difficult and error-prone task. Computational genetics researchers currently re-implement simulation models independently, leading to inconsistency and duplication of effort. This situation presents a major barrier to empirical researchers seeking to use simulations for power analyses of upcoming studies or sanity checks on existing genomic data. Population genetics, as a field, also lacks standard benchmarks by which new tools for inference might be measured. Here, we describe a new resource, stdpopsim, that attempts to rectify this situation. Stdpopsim is a community-driven open source project, which provides easy access to a growing catalog of published simulation models from a range of organisms and supports multiple simulation engine backends. This resource is available as a well-documented python library with a simple command-line interface. We share some examples demonstrating how stdpopsim can be used to systematically compare demographic inference methods, and we encourage a broader community of developers to contribute to this growing resource.
    • A comparison of text versus audio for information comprehension with future uses for smart speakers

      Leroy, G.; Kauchak, D.; University of Arizona (Oxford University Press, 2019)
      Objective: Audio is increasingly used to access information on the Internet through virtual assistants and smart speakers. Our objective is to evaluate the distribution of health information through audio. Materials and Methods: We conducted 2 studies to compare comprehension after reading or listening to information using a new corpus containing short text snippets from Cochrane (N=50) and Wikipedia (N=50). In study 1, the snippets were first presented as audio or text followed by a multiple-choice question. Then, the same information was presented as text and the question was repeated in addition to questions about perceived difficulty, severity and the likelihood of encountering the disease. In study 2, the first multiple-choice question was replaced with a free recall question. Results: Study 1 showed that information comprehension is very similar in both presentation modes (53% accuracy for text and 55% for audio). Study 2 showed that information retention is higher with text, but similar comprehension. Both studies show improvement in performance with repeated information presentation. Discussion: Audio presentation of information is effective and the format novel. Performance was slightly lower with audio when asked to repeat information, but comparable to text for answering questions. Additional studies are needed with different types of information and presentation combinations. Conclusion: The use of audio to provide health information is a promising field and will become increasingly important with the popularity of smart speakers and virtual assistants, particularly for consumers who do not use computers, for example minority groups, or those with limited sight or motor control. © The Author(s) 2019.
    • A Comprehensive Analysis of Triggers and Risk Factors for Asthma Based on Machine Learning and Large Heterogeneous Data Sources

      Zhang, Wenli; Ram, Sudha; Univ Arizona, Eller Coll Management (SOC INFORM MANAGE-MIS RES CENT, 2020)
      Asthma is a common chronic health condition affecting millions of people in the United States. While asthma cannot be cured, it can be managed if we identify and understand triggers and risk factors that cause asthma exacerbations. However, this is challenging because these triggers and risk factors are complex and interconnected, and there are limitations to current mainstream approaches for identifying them. The recent availability of massive amounts of heterogeneous data has opened up new possibilities for asthma triggers and risk factors analyses. In this study, we introduce a data-driven framework, adapt and integrate multiple advanced machine learning techniques, and perform an empirical analysis to (1) derive characteristics of selfreported asthma patients from social media, (2) enable integration and repurposing of highly heterogeneous and commonly available datasets, and (3) uncover the sequential patterns of asthma triggers and risk factors, and their relative importance, both of which are difficult to achieve via retrospective cohort-based studies. Our methods and results can provide guidance for developing asthma management plans and interventions for specific subpopulations and, eventually, have the potential to reduce the societal burden of asthma.
    • A critical role of hepatic GABA in the metabolic dysfunction and hyperphagia of obesity

      Geisler, C.E.; Ghimire, S.; Bruggink, S.M.; Miller, K.E.; Weninger, S.N.; Kronenfeld, J.M.; Yoshino, J.; Klein, S.; Duca, F.A.; Renquist, B.J.; et al. (Elsevier B.V., 2021)
      Hepatic lipid accumulation is a hallmark of type II diabetes (T2D) associated with hyperinsulinemia, insulin resistance, and hyperphagia. Hepatic synthesis of GABA, catalyzed by GABA-transaminase (GABA-T), is upregulated in obese mice. To assess the role of hepatic GABA production in obesity-induced metabolic and energy dysregulation, we treated mice with two pharmacologic GABA-T inhibitors and knocked down hepatic GABA-T expression using an antisense oligonucleotide. Hepatic GABA-T inhibition and knockdown decreased basal hyperinsulinemia and hyperglycemia and improved glucose intolerance. GABA-T knockdown improved insulin sensitivity assessed by hyperinsulinemic-euglycemic clamps in obese mice. Hepatic GABA-T knockdown also decreased food intake and induced weight loss without altering energy expenditure in obese mice. Data from people with obesity support the notion that hepatic GABA production and transport are associated with serum insulin, homeostatic model assessment for insulin resistance (HOMA-IR), T2D, and BMI. These results support a key role for hepatocyte GABA production in the dysfunctional glucoregulation and feeding behavior associated with obesity. © 2021
    • A Diffuse Metal-poor Component of the Sagittarius Stream Revealed by the H3 Survey

      Johnson, Benjamin D.; Conroy, Charlie; Naidu, Rohan P.; Bonaca, Ana; Zaritsky, Dennis; Ting, Yuan-Sen; Cargile, Phillip A.; Han, Jiwon Jesse; Speagle, Joshua S.; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2020-09)
      The tidal disruption of the Sagittarius dwarf galaxy has generated a spectacular stream of stars wrapping around the entire Galaxy. We use data from Gaia and the H3 Stellar Spectroscopic Survey to identify 823 high-quality Sagittarius members based on their angular momenta. The H3 Survey is largely unbiased in metallicity, and so our sample of Sagittarius members is similarly unbiased. Stream stars span a wide range in [Fe/H] from -0.2 to -3.0, with a mean overall metallicity of <[F/H]> = -0.99. We identify a strong metallicity dependence to the kinematics of the stream members. At [Fe/H] > -0.8 nearly all members belong to the well-known cold (sigma(v) < 20 km s(-1)) leading and trailing arms. At intermediate metallicities (-1.9 < [Fe/H] < -0.8) a significant population (24%) emerges of stars that are kinematically offset from the cold arms. These stars also appear to have hotter kinematics. At the lowest metallicities ([Fe/H] less than or similar to -2), the majority of stars (69%) belong to this kinematically offset diffuse population. Comparison to simulations suggests that the diffuse component was stripped from the Sagittarius progenitor at earlier epochs, and therefore resided at larger radius on average than the colder metal-rich component. We speculate that this kinematically diffuse, low-metallicity population is the stellar halo of the Sagittarius progenitor system.
    • A diffuse tidal dwarf galaxy destined to fade out as a "dark galaxy"

      Román, J.; Jones, M.G.; Montes, M.; Verdes-Montenegro, L.; Garrido, J.; Sánchez, S.; Steward Observatory, University of Arizona (EDP Sciences, 2021)
      We have explored the properties of a peculiar object detected in deep optical imaging and located at the tip of an H » I tail emerging from Hickson Compact Group 16. Using multiband photometry from infrared to ultraviolet, we were able to constrain its stellar age to 58-9+22 Myr with a rather high metallicity of [Fe/H] = -0.16-0.41+0.43 for its stellar mass of M- = 4.2 × 106 Mpdbl, a typical signature of tidal dwarf galaxies. The structural properties of this object are similar to those of diffuse galaxies, with a round and featureless morphology, a large effective radius (reff = 1.5 kpc), and a low surface brightness (μg-eff = 25.6 mag arcsec-2). Assuming that the object is dynamically stable and able to survive in the future, its fading in time via the aging of its stellar component will make it undetectable in optical observations in just ∼2 Gyr of evolution, even in the deepest current or future optical surveys. Its high H » I mass, M(HI) = 3.9 × 108 Mpdbl, and future undetectable stellar component will make the object match the observational properties of dark galaxies, that is, dark matter halos that failed to turn gas into stars. Our work presents further observational evidence of the feasibility of H » I tidal features becoming fake dark galaxies; it also shows the impact of stellar fading, particularly in high metallicity systems such as tidal dwarfs, in hiding aged stellar components beyond detection limits in optical observations. © ESO 2021.
    • A domeless, mobile 2-meter telescope

      Kingsley, J.; Strittmatter, P.; Gonzales, K.; Connors, T.; Kingsley, B.; Jannuzi, B.; Yoshii, Y.; Minezaki, T.; Steward Observatory, The University of Arizona (SPIE, 2020)
      There are many astronomical, interferometric and space situational awareness applications for single and multiple 2-meter aperture optical and infrared mobile telescopes that are low cost, can be easily transported and quickly deployed at a variety of sites. A design concept is presented for a trailermounted 2-meter telescope with a novel micro-enclosure that allows the telescope to be moved and deployed quickly for observations. The telescope is protected from adverse weather using a weatherproof telescope tube instead of a conventional dome or enclosure. It has Cassegrain, Nasmyth and coudé foci suitable for astronomical, interferometric, space situational awareness, and laser communications applications, and is designed for replication at low cost. An initial implementation is being developed to explore the performance of such a telescope using re-purposed primary and secondary mirrors and other components from the MAGNUM telescope. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
    • A genetic study of cerebral atherosclerosis reveals novel associations with ntng1 and cnot3

      Vattathil, S.M.; Liu, Y.; Harerimana, N.V.; Lori, A.; Gerasimov, E.S.; Beach, T.G.; Reiman, E.M.; De Jager, P.L.; Schneider, J.A.; Bennett, D.A.; et al. (MDPI AG, 2021)
      Cerebral atherosclerosis is a leading cause of stroke and an important contributor to dementia. Yet little is known about its genetic basis. To examine the association of common single nucleotide polymorphisms with cerebral atherosclerosis severity, we conducted a genomewide association study (GWAS) using data collected as part of two community-based cohort studies in the United States, the Religious Orders Study (ROS) and Rush Memory and Aging Project (MAP). Both studies enroll older individuals and exclude participants with signs of dementia at baseline. From our analysis of 1325 participants of European ancestry who had genotype and neuropathologically assessed cerebral atherosclerosis measures available, we found a novel locus for cerebral atherosclerosis in NTNG1. The locus comprises eight SNPs, including two independent significant SNPs: rs6664221 (β = −0.27, 95% CI = (−0.35, −0.19), p = 1.29 × 10−10 ) and rs10881463 (β = −0.20, 95% CI = (−0.27, −0.13), p = 3.40 × 10−8 ). We further found that the SNPs may influence cerebral atherosclerosis by regulating brain protein expression of CNOT3. CNOT3 is a subunit of CCR4−NOT, which has been shown to be a master regulator of mRNA stability and translation and an important complex for cholesterol homeostasis. In summary, we identify a novel genetic locus for cerebral atherosclerosis and a potential mechanism linking this variation to cerebral atherosclerosis progression. These findings offer insights into the genetic effects on cerebral atherosclerosis. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
    • A harsh test of far-field scrambling with the habitable-zone planet finder and the hobby–eberly telescope

      Kanodia, S.; Halverson, S.; Ninan, J.P.; Mahadevan, S.; Stefansson, G.; Roy, A.; Ramsey, L.W.; Bender, C.F.; Janowiecki, S.; Cochran, W.D.; et al. (IOP Publishing Ltd, 2021)
      The Habitable-zone Planet Finder (HPF) is a fiber-fed precise radial velocity (RV) spectrograph at the 10 m Hobby–Eberly Telescope (HET). Due to its fixed-altitude design, the HET pupil changes appreciably across a track, leading to significant changes of the fiber far-field illumination. HPF’s fiber scrambler is designed to suppress the impact of these illumination changes on the RVs—but the residual impact on the RV measurements has yet to be probed on-sky. We use GJ 411, a bright early type (M2) M dwarf to probe the effects of far-field input trends due to these pupil variations on HPF RVs. These large changes (∼2x) in the pupil area and centroid present a harsh test of HPF’s far-field scrambling. Our results show that the RVs are effectively decoupled from these extreme far-field input changes due to pupil centroid offsets, attesting to the effectiveness of the scrambler design. This experiment allows us to test the impact of these changes with large pupil variation on-sky, something we would not easily be able to do at a conventional optical telescope. While the pupil and illumination changes expected at these other telescopes are small, scaling from our results enables us to estimate and bound these effects, and show that they are controllable even for the new and next generation of RV instruments in their quest to beat down instrumental noise sources toward the goal of a few cm s-1. © 2021. The American Astronomical Society. All rights reserved.
    • A high-contrast search for variability in HR 8799bc with VLT-SPHERE

      Biller, B.A.; Apai, D.; Bonnefoy, M.; Desidera, S.; Gratton, R.; Kasper, M.; Kenworthy, M.; Lagrange, A.-M.; Lazzoni, C.; Mesa, D.; et al. (Oxford University Press, 2021)
      The planets HR8799bc display nearly identical colours and spectra as variable young exoplanet analogs such as VHS 1256-1257ABb and PSO J318.5-22, and are likely to be similarly variable. Here we present results from a 5-epoch SPHERE IRDIS broadband-H search for variability in these two planets. HR 8799b aperture photometry and HR 8799bc negative simulated planet photometry share similar trends within uncertainties. Satellite spot lightcurves share the same trends as the planet lightcurves in the August 2018 epochs, but diverge in the October 2017 epochs. We consider Δ(mag)b-Δ(mag)c to trace non-shared variations between the two planets, and rule out non-shared variability in Δ(mag)b-Δ(mag)c to the 10-20 rm per\cent level over 4-5 h. To quantify our sensitivity to variability, we simulate variable lightcurves by inserting and retrieving a suite of simulated planets at similar radii from the star as HR 8799bc, but offset in position angle. For HR 8799b, for periods <10 h, we are sensitive to variability with amplitude > 5 per\cent. For HR 8799c, our sensitivity is limited to variability > 25 per\cent for similar periods. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.
    • A laser-truss based optical alignment system on LBT

      Rakich, A.; Choi, H.; Veillet, C.; Hill, J.M.; Bec, M.; Zhang, Y.; Brendel, T.; Sitarski, B.; Gardiner, M.; Kim, D.W.; et al. (SPIE, 2020)
      Since 2017 LBTO, in partnership with GMTO, has been developing a laser-trussed based metrology system for the active alignment of telescope main optical components to each other and to instruments. The effort has addressed needs of both organizations; LBTO with the opportunity to assess the performance of a new technological approach to telescope alignment, and the GMTO with the opportunity to prototype and field-test a system that has been identified as a crucial "missing link"in the active-optics chain between open-loop modelling and wavefront-sensing for ELT-scale telescopes. Following two years of effort the positive results so far obtained have convinced LBTO, in 2019, to commence to develop an integrated operational active-optics system based on this technological approach. A team drawn from LBTO, Steward Observatory, GMTO, the Wyant College of Optical Sciences and Mersenne Optical Consulting are currently completing the first phase of this Telescope Metrology System (TMS). This paper shall describe the system in detail and report on progress, current status, and future goals. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
    • A mechanistic analysis of tropical Pacific dynamic sea level in GFDL-OM4 under OMIP-I and OMIP-II forcings

      Hsu, C.-W.; Yin, J.; Griffies, S.M.; Dussin, R.; University of Arizona, Department of Geoscience (Copernicus GmbH, 2021)
      The sea level over the tropical Pacific is a key indicator reflecting vertically integrated heat distribution over the ocean. Here, we use the Geophysical Fluid Dynamics Laboratory global ocean-sea ice model (GFDL-OM4) forced by both the Coordinated Ocean-Ice Reference Experiment (CORE) and Japanese 55-year Reanalysis (JRA-55)-based surface dataset for driving ocean-sea ice models (JRA55-do) atmospheric states (Ocean Model Intercomparison Project (OMIP) versions I and II) to evaluate the model performance and biases compared against available observations. We find persisting mean state dynamic sea level (DSL) bias along 9° N even with updated wind forcing in JRA55-do relative to CORE. The mean state bias is related to biases in wind stress forcing and geostrophic currents in the 4 to 9° N latitudinal band. The simulation forced by JRA55-do significantly reduces the bias in DSL trend over the northern tropical Pacific relative to CORE. In the CORE forcing, the anomalous westerly wind trend in the eastern tropical Pacific causes an underestimated DSL trend across the entire Pacific basin along 10° N. The simulation forced by JRA55-do significantly reduces the bias in DSL trend over the northern tropical Pacific relative to CORE. We also identify a bias in the easterly wind trend along 20° N in both JRA55-do and CORE, thus motivating future improvement. In JRA55-do, an accurate Rossby wave initiated in the eastern tropical Pacific at seasonal timescale corrects a biased seasonal variability of the northern equatorial countercurrent in the CORE simulation. Both CORE and JRA55-do generate realistic DSL variation during El Niño. We find an asymmetry in the DSL pattern on two sides of the Equator is strongly related to wind stress curl that follows the sea level pressure evolution during El Niño. © 2021 The Author(s).