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Liu F, Ting YS, Yong D, Bitsch B, Karakas A, Murphy MT, Joyce M, Dotter A, Dai F. At least one in a dozen stars shows evidence of planetary ingestion. Nature 2024; 627:501-504. [PMID: 38509276 DOI: 10.1038/s41586-024-07091-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/18/2024] [Indexed: 03/22/2024]
Abstract
Stellar chemical compositions can be altered by ingestion of planetary material1,2 and/or planet formation, which removes refractory material from the protostellar disk3,4. These 'planet signatures' appear as correlations between elemental abundance differences and the dust condensation temperature3,5,6. Detecting these planet signatures, however, is challenging owing to unknown occurrence rates, small amplitudes and heterogeneous star samples with large differences in stellar ages7,8. Therefore, stars born together (that is, co-natal) with identical compositions can facilitate the detection of planet signatures. Although previous spectroscopic studies have been limited to a small number of binary stars9-13, the Gaia satellite14 provides opportunities for detecting stellar chemical signatures of planets among co-moving pairs of stars confirmed to be co-natal15,16. Here we report high-precision chemical abundances for a homogeneous sample of ninety-one co-natal pairs of stars with a well defined selection function and identify at least seven instances of planetary ingestion, corresponding to an occurrence rate of eight per cent. An independent Bayesian indicator is deployed, which can effectively disentangle the planet signatures from other factors, such as random abundance variation and atomic diffusion17. Our study provides evidence of planet signatures and facilitates a deeper understanding of the star-planet-chemistry connection by providing observational constraints on the mechanisms of planet engulfment, formation and evolution.
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Affiliation(s)
- Fan Liu
- School of Physics and Astronomy, Monash University, Clayton, Victoria, Australia.
- Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria, Australia.
- ARC Centre for All Sky Astrophysics in 3D (ASTRO-3D), Canberra, Australian Capital Territory, Australia.
| | - Yuan-Sen Ting
- ARC Centre for All Sky Astrophysics in 3D (ASTRO-3D), Canberra, Australian Capital Territory, Australia
- Research School of Astronomy and Astrophysics, Australian National University, Weston, Australian Capital Territory, Australia
- School of Computing, Australian National University, Acton, Australian Capital Territory, Australia
- Department of Astronomy, The Ohio State University, Columbus, OH, USA
- Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, OH, USA
- Observatories of the Carnegie Institution of Washington, Pasadena, CA, USA
| | - David Yong
- ARC Centre for All Sky Astrophysics in 3D (ASTRO-3D), Canberra, Australian Capital Territory, Australia
- Research School of Astronomy and Astrophysics, Australian National University, Weston, Australian Capital Territory, Australia
| | - Bertram Bitsch
- Max-Planck-Institut für Astronomie, Heidelberg, Germany
- Department of Physics, University College Cork, Cork, Ireland
| | - Amanda Karakas
- School of Physics and Astronomy, Monash University, Clayton, Victoria, Australia
- ARC Centre for All Sky Astrophysics in 3D (ASTRO-3D), Canberra, Australian Capital Territory, Australia
| | - Michael T Murphy
- Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Meridith Joyce
- HUN-REN Research Centre for Astronomy and Earth Sciences, Konkoly Observatory, Budapest, Hungary
- CSFK, MTA Centre of Excellence, Budapest, Hungary
| | - Aaron Dotter
- Department of Physics and Astronomy, Dartmouth College, Hanover, NH, USA
| | - Fei Dai
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- Department of Astronomy, California Institute of Technology, Pasadena, CA, USA
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Ting YS, Smith SABC, Brown DA, Dodds AJ, Fay KC, Ma DDF, Milliken S, Moore JJ, Sewell WA. CD200 is a useful diagnostic marker for identifying atypical chronic lymphocytic leukemia by flow cytometry. Int J Lab Hematol 2018; 40:533-539. [PMID: 29806244 DOI: 10.1111/ijlh.12857] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 04/11/2018] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Immunophenotyping by flow cytometry is routinely employed in distinguishing between chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). Inclusion of CD200 has been reported to contribute to more reliable differentiation between CLL and MCL. We investigated the value of CD200 in assessment of atypical CLL cases. METHODS CD200 expression on mature B cell neoplasms was studied by eight-color flow cytometry in combination with a conventional panel of flow cytometry markers. The study included 70 control samples, 63 samples with CLL or atypical CLL phenotype, 6 MCL samples, and 40 samples of other mature B cell neoplasms. RESULTS All CLL samples were positive for CD200, whereas MCL samples were dim or negative for CD200. Of the CLL samples, 7 were atypical by conventional flow cytometry, with Matutes scores ≤3. These cases were tested for evidence of a t(11;14) translocation, characteristic of MCL, and all were negative, consistent with their classification as atypical CLL. All these atypical CLL samples were strongly positive for CD200. CONCLUSION CD200 proved to be a useful marker for differentiation between CLL and MCL by flow cytometry. In particular, CD200 was useful in distinguishing CLL samples with atypical immunophenotypes from MCL.
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Affiliation(s)
- Y S Ting
- St Vincent's Pathology (SydPath), St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia
| | - S A B C Smith
- St Vincent's Pathology (SydPath), St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia
| | - D A Brown
- St Vincent's Pathology (SydPath), St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.,St Vincent's Centre for Applied Medical Research, Darlinghurst, NSW, Australia.,NSW Health Pathology and ICPMR, Westmead, NSW, Australia
| | - A J Dodds
- St Vincent's Pathology (SydPath), St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.,Haematology Department, St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia
| | - K C Fay
- St Vincent's Pathology (SydPath), St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia.,Haematology Department, St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia
| | - D D F Ma
- St Vincent's Pathology (SydPath), St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.,St Vincent's Centre for Applied Medical Research, Darlinghurst, NSW, Australia.,Haematology Department, St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia
| | - S Milliken
- St Vincent's Pathology (SydPath), St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.,Haematology Department, St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia
| | - J J Moore
- St Vincent's Pathology (SydPath), St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.,Haematology Department, St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia
| | - W A Sewell
- St Vincent's Pathology (SydPath), St Vincent's Hospital Sydney, Darlinghurst, NSW, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.,Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
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Yang HM, Ting YS, Wong KYM. Effects of payoff functions and preference distributions in an adaptive population. Phys Rev E Stat Nonlin Soft Matter Phys 2008; 77:031116. [PMID: 18517338 DOI: 10.1103/physreve.77.031116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 11/19/2007] [Indexed: 05/26/2023]
Abstract
Adaptive populations such as those in financial markets and distributed control can be modeled by the Minority Game. We consider how their dynamics depends on the agents' initial preferences of strategies, when the agents use linear or quadratic payoff functions to evaluate their strategies. We find that the fluctuations of the population making certain decisions (the volatility) depends on the diversity of the distribution of the initial preferences of strategies. When the diversity decreases, more agents tend to adapt their strategies together. In systems with linear payoffs, this results in dynamical transitions from vanishing volatility to a nonvanishing one. For low signal dimensions, the dynamical transitions for the different signals do not take place at the same critical diversity. Rather, a cascade of dynamical transitions takes place when the diversity is reduced. In contrast, no phase transitions are found in systems with the quadratic payoffs. Instead, a basin boundary of attraction separates two groups of samples in the space of the agents' decisions. Initial states inside this boundary converge to small volatility, while those outside diverge to a large one. Furthermore, when the preference distribution becomes more polarized, the dynamics becomes more erratic. All the above results are supported by good agreement between simulations and theory.
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Affiliation(s)
- H M Yang
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China.
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Abstract
A Nafion-ruthenium oxide pyrochlore chemically modified electrode is used for the determination of caffeine in beverages by square-wave voltammetry. Compared to a bare glassy carbon electrode, the chemically modified electrode exhibits a marked enhancement of the current response. A linear calibration curve is obtained over the 5-200 microns range in 0.05 M HCIO4 solution with a detection limit (3 delta) of 2 micron. The results of 15 successive repetitive measurement-regeneration cycles showed a relative standard deviation of 2.7% for 10 micron caffeine. Thus, the electrode renewal gives a good reproducible surface. Quantitative analysis was performed by the standard addition method for caffeine content in tea, coffee, decaffeinated coffee, and cola beverages.
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Affiliation(s)
- J M Zen
- Department of Chemistry, National Chung-Hsing University, Taichung, Taiwan
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