Personal information

No personal information available

Activities

Collapse all

Employment (1)

The University of Texas Rio Grande Valley: Edinburg, US

2024-09-01 to present | Assistant Professor (Physics & Astronomy)
Employment
Source: Self-asserted source
Ryan J. Oelkers

Education and qualifications (4)

Texas A&M University: College Station, TX, US

2010-08 to 2016-05 | Doctor of Philosophy (Physics and Astronomy)
Education
Source: Self-asserted source
Ryan J. Oelkers

Texas A&M University: College Station, TX, US

2010-08 to 2015-05 | Masters of Science (Physics and Astronomy)
Education
Source: Self-asserted source
Ryan J. Oelkers

Northwestern University: Evanston, IL, US

2009-09 to 2010-06 | Masters of Science (Engineering Science and Applied Mathematics)
Education
Source: Self-asserted source
Ryan J. Oelkers

Stevens Institute of Technology: Hoboken, NJ, US

2005-08 to 2009-05 | Bachelors of Science (Mathematics)
Education
Source: Self-asserted source
Ryan J. Oelkers

Works (42)

Ground-based Reconnaissance Observations of 21 Exoplanet Atmospheres with the Exoplanet Transmission Spectroscopy Imager

The Astronomical Journal
2025-03-03 | Journal article
DOI: 10.3847/1538-3881/ada557
Contributors: Ryan J. Oelkers; Luke M. Schmidt; Erika Cook; Mary Anne Limbach; D. L. DePoy; J. L. Marshall; Jimmy Ardoin; Mitchell Barry; Evan Batteas; Alexandra Boone et al.
Source: check_circle
Crossref

Another shipment of six short-period giant planets from TESS

Monthly Notices of the Royal Astronomical Society
2023-05 | Journal article
DOI: 10.1093/mnras/stad595
BIBCODE: 2023MNRAS.521.2765R
ARXIV: 2205.05709
Contributors: Rodriguez, Joseph E.; Quinn, Samuel N.; Vanderburg, Andrew; Zhou, George; Eastman, Jason D.; Thygesen, Erica; Cale, Bryson; Ciardi, David R.; Reed, Phillip A.; Oelkers, Ryan J. et al.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

Eclipse of the V773 Tau B circumbinary disc

Astronomy and Astrophysics
2022-10 | Journal article
DOI: 10.1051/0004-6361/202243441
BIBCODE:

2022A&A...666A..61K

ARXIV: 2207.05575
Contributors: Kenworthy, M. A.; González Picos, D.; Elizondo, E.; Martin, R. G.; van Dam, D. M.; Rodriguez, J. E.; Kennedy, G. M.; Ginski, C.; Mugrauer, M.; Vogt, N. et al.
Source: check_circle
NASA Astrophysics Data System

SpinSpotter : An Automated Algorithm for Identifying Stellar Rotation Periods with Autocorrelation Analysis

The Astrophysical Journal
2022-09 | Journal article
DOI: 10.3847/1538-4357/ac8990
BIBCODE: 2022ApJ...936..138H
ARXIV: 2206.10629
Contributors: Holcomb, Rae J.; Robertson, Paul; Hartigan, Patrick; Oelkers, Ryan J.; Robinson, Caleb
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

H-band Light Curves of Milky Way Cepheids via Difference Imaging

The Astrophysical Journal Supplement Series
2022-01 | Journal article
DOI: 10.3847/1538-4365/ac41d3
BIBCODE: 2022ApJS..258...24K
ARXIV: 2112.04597
Contributors: Konchady, Tarini; Oelkers, Ryan J.; Jones, David O.; Yuan, Wenlong; Macri, Lucas M.; Peterson, Erik R.; Riess, Adam G.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

Two Massive Jupiters in Eccentric Orbits from the TESS Full-frame Images

The Astronomical Journal
2022-01 | Journal article
DOI: 10.3847/1538-3881/ac2ee1
BIBCODE: 2022AJ....163....9I
ARXIV: 2102.02222
Contributors: Ikwut-Ukwa, Mma; Rodriguez, Joseph E.; Quinn, Samuel N.; Zhou, George; Vanderburg, Andrew; Ali, Asma; Bunten, Katya; Gaudi, B. Scott; Latham, David W.; Howell, Steve B. et al.
Source: check_circle
NASA Astrophysics Data System

Final Targeting Strategy for the SDSS-IV APOGEE-2S Survey

The Astronomical Journal
2021-12 | Journal article
DOI: 10.3847/1538-3881/ac2cbc
BIBCODE: 2021AJ....162..303S
ARXIV: 2108.11908
Contributors: Santana, Felipe A.; Beaton, Rachael L.; Covey, Kevin R.; O'Connell, Julia E.; Longa-Peña, Penélope; Cohen, Roger; Fernández-Trincado, José G.; Hayes, Christian R.; Zasowski, Gail; Sobeck, Jennifer S. et al.
Source: check_circle
NASA Astrophysics Data System

Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey

The Astronomical Journal
2021-12 | Journal article
DOI: 10.3847/1538-3881/ac260c
BIBCODE: 2021AJ....162..302B
ARXIV: 2108.11907
Contributors: Beaton, Rachael L.; Oelkers, Ryan J.; Hayes, Christian R.; Covey, Kevin R.; Chojnowski, S. D.; De Lee, Nathan; Sobeck, Jennifer S.; Majewski, Steven R.; Cohen, Roger E.; Fernández-Trincado, José et al.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

The TESS Mission Target Selection Procedure

Publications of the Astronomical Society of the Pacific
2021-09 | Journal article
DOI: 10.1088/1538-3873/ac1d3f
BIBCODE: 2021PASP..133i5002F
ARXIV: 2109.02665
Contributors: Fausnaugh, Michael; Morgan, Ed; Vanderspek, Roland; Pepper, Joshua; Burke, Christopher J.; Levine, Alan M.; Rudat, Alexander; Villaseñor, Jesus Noel S.; Vezie, Michael; Goeke, Robert F. et al.
Source: check_circle
NASA Astrophysics Data System

The Stellar and Observational Properties of the TESS Prime Mission 2-min Targets

Posters from the TESS Science Conference II (TSC2)
2021-07 | Conference paper
DOI: 10.5281/zenodo.5130883
BIBCODE: 2021tsc2.confE.139P
Contributors: Pepper, Joshua; Barclay, Thomas; Bouma, Luke G.; Burke, Christopher J.; Fausnaugh, Michael; Gaudi, B. Scott; Oelkers, Ryan J.; Stassun, Keivan G.; Winn, Joshua N.
Source: check_circle
NASA Astrophysics Data System

TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars from the Full-frame Images

The Astronomical Journal
2021-04 | Journal article
DOI: 10.3847/1538-3881/abe38a
BIBCODE: 2021AJ....161..194R
ARXIV: 2101.01726
Contributors: Rodriguez, Joseph E.; Quinn, Samuel N.; Zhou, George; Vanderburg, Andrew; Nielsen, Louise D.; Wittenmyer, Robert A.; Brahm, Rafael; Reed, Phillip A.; Huang, Chelsea X.; Vach, Sydney et al.
Source: check_circle
NASA Astrophysics Data System

Stellar Flares from the First TESS Data Release: Exploring a New Sample of M Dwarfs

The Astronomical Journal
2020-02 | Journal article
DOI: 10.3847/1538-3881/ab5d3a
BIBCODE: 2020AJ....159...60G
ARXIV: 1901.00443
Contributors: Günther, Maximilian N.; Zhan, Zhuchang; Seager, Sara; Rimmer, Paul B.; Ranjan, Sukrit; Stassun, Keivan G.; Oelkers, Ryan J.; Daylan, Tansu; Newton, Elisabeth; Kristiansen, Martti H. et al.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

KELT-24b: A 5M <SUB>J</SUB> Planet on a 5.6 day Well-aligned Orbit around the Young V = 8.3 F-star HD 93148

The Astronomical Journal
2019-11 | Journal article
DOI: 10.3847/1538-3881/ab4136
BIBCODE: 2019AJ....158..197R
ARXIV: 1906.03276
Contributors: Rodriguez, Joseph E.; Eastman, Jason D.; Zhou, George; Quinn, Samuel N.; Beatty, Thomas G.; Penev, Kaloyan; Johnson, Marshall C.; Cargile, Phillip A.; Latham, David W.; Bieryla, Allyson et al.
Source: check_circle
NASA Astrophysics Data System

The Revised TESS Input Catalog and Candidate Target List

The Astronomical Journal
2019-10 | Journal article
DOI: 10.3847/1538-3881/ab3467
BIBCODE: 2019AJ....158..138S
ARXIV: 1905.10694
Contributors: Stassun, Keivan G.; Oelkers, Ryan J.; Paegert, Martin; Torres, Guillermo; Pepper, Joshua; De Lee, Nathan; Collins, Kevin; Latham, David W.; Muirhead, Philip S.; Chittidi, Jay et al.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

An Eccentric Massive Jupiter Orbiting a Subgiant on a 9.5-day Period Discovered in the Transiting Exoplanet Survey Satellite Full Frame Images

The Astronomical Journal
2019-05 | Journal article
DOI: 10.3847/1538-3881/ab11d9
BIBCODE: 2019AJ....157..191R
ARXIV: 1901.09950
Contributors: Rodriguez, Joseph E.; Quinn, Samuel N.; Huang, Chelsea X.; Vanderburg, Andrew; Penev, Kaloyan; Brahm, Rafael; Jordán, Andrés; Ikwut-Ukwa, Mma; Tsirulik, Shelly; Latham, David W. et al.
Source: check_circle
NASA Astrophysics Data System

TESS Habitable Zone Star Catalog

The Astrophysical Journal
2019-03 | Journal article
DOI: 10.3847/2041-8213/ab0e8d
BIBCODE: 2019ApJ...874L...8K
ARXIV: 1903.11539
Contributors: Kaltenegger, L.; Pepper, J.; Stassun, K.; Oelkers, R.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

Light Curves for All Stars Observed in TESS Full-frame Images: Sector 1 and Beyond

Research Notes of the American Astronomical Society
2019-01 | Journal article
DOI: 10.3847/2515-5172/aafc34
BIBCODE: 2019RNAAS...3....8O
Contributors: Oelkers, Ryan J.; Stassun, Keivan G.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

Erratum: The TESS Input Catalog and Candidate Target List (<A href="http://doi.org/10.3847/1538-3881/aad050"> 2018, AJ, 156, 102</A>)

The Astronomical Journal
2018-10 | Journal article
DOI: 10.3847/1538-3881/aade86
BIBCODE: 2018AJ....156..183S
Contributors: Stassun, Keivan G.; Oelkers, Ryan J.; Pepper, Joshua; Paegert, Martin; Bastien, Fabian A.; De Lee, Nathan; Torres, Guillermo; Latham, David W.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

The TESS Input Catalog and Candidate Target List

The Astronomical Journal
2018-09 | Journal article
DOI: 10.3847/1538-3881/aad050
BIBCODE: 2018AJ....156..102S
ARXIV: 1706.00495
Contributors: Stassun, Keivan G.; Oelkers, Ryan J.; Pepper, Joshua; Paegert, Martin; De Lee, Nathan; Torres, Guillermo; Latham, David W.; Charpinet, Stéphane; Dressing, Courtney D.; Huber, Daniel et al.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

Precision Light Curves from <i>TESS</i> Full-frame Images: A Different Imaging Approach

The Astronomical Journal
2018-08-29 | Journal article | Author
DOI: 10.3847/1538-3881/aad68e
Part of ISSN: 1538-3881
Contributors: Ryan J. Oelkers; Keivan G. Stassun
Source: Self-asserted source
Ryan J. Oelkers
grade
Preferred source (of 3)‎

A Catalog of Cool Dwarf Targets for the Transiting Exoplanet Survey Satellite

The Astronomical Journal
2018-04 | Journal article
DOI: 10.3847/1538-3881/aab710
BIBCODE: 2018AJ....155..180M
ARXIV: 1710.00193
Contributors: Muirhead, Philip S.; Dressing, Courtney D.; Mann, Andrew W.; Rojas-Ayala, Bárbara; Lépine, Sébastien; Paegert, Martin; De Lee, Nathan; Oelkers, Ryan
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

Variability Properties of Four Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey

The Astronomical Journal
2018-01 | Journal article
DOI: 10.3847/1538-3881/aa9bf4
BIBCODE: 2018AJ....155...39O
ARXIV: 1711.03608
Contributors: Oelkers, Ryan J.; Rodriguez, Joseph E.; Stassun, Keivan G.; Pepper, Joshua; Somers, Garrett; Kafka, Stella; Stevens, Daniel J.; Beatty, Thomas G.; Siverd, Robert J.; Lund, Michael B. et al.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

KELT-20b: A Giant Planet with a Period of P ∼ 3.5 days Transiting the V ∼ 7.6 Early A Star HD 185603

The Astronomical Journal
2017-11 | Journal article
DOI: 10.3847/1538-3881/aa8f95
BIBCODE: 2017AJ....154..194L
ARXIV: 1707.01518
Contributors: Lund, Michael B.; Rodriguez, Joseph E.; Zhou, George; Gaudi, B. Scott; Stassun, Keivan G.; Johnson, Marshall C.; Bieryla, Allyson; Oelkers, Ryan J.; Stevens, Daniel J.; Collins, Karen A. et al.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

Erratum "Gaia Assorted Mass Binaries Long Excluded from SLoWPoKES (GAMBLES): Identifying Ultra-wide Binary Pairs with Components of Diverse Mass" (2017, AJ, 153, 259)

The Astronomical Journal
2017-10 | Journal article
DOI: 10.3847/1538-3881/aa886d
BIBCODE: 2017AJ....154..174O
Contributors: Oelkers, Ryan J.; Stassun, Keivan G.; Dhital, Saurav
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

Identification of Young Stellar Variables with KELT for K2. I. Taurus Dippers and Rotators

The Astrophysical Journal
2017-10 | Journal article
DOI: 10.3847/1538-4357/aa8c78
BIBCODE: 2017ApJ...848...97R
ARXIV: 1703.02522
Contributors: Rodriguez, Joseph E.; Ansdell, Megan; Oelkers, Ryan J.; Cargile, Phillip A.; Gaidos, Eric; Cody, Ann Marie; Stevens, Daniel J.; Somers, Garrett; James, David; Beatty, Thomas G. et al.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

Target Selection for the SDSS-IV APOGEE-2 Survey

The Astronomical Journal
2017-10-25 | Journal article | Author
DOI: 10.3847/1538-3881/aa8df9
Part of ISSN: 1538-3881
Contributors: G. Zasowski; R. E. Cohen; S. Drew Chojnowski; Felipe Santana Rojas; Ryan J. Oelkers; Brett Andrews; Rachael Beaton; C. Bender; J. C. Bird; Jo Bovy et al.
Source: Self-asserted source
Ryan J. Oelkers
grade
Preferred source (of 3)‎

Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe

The Astronomical Journal
2017-07 | Journal article
DOI: 10.3847/1538-3881/aa7567
BIBCODE: 2017AJ....154...28B
ARXIV: 1703.00052
Contributors: Blanton, Michael R.; Bershady, Matthew A.; Abolfathi, Bela; Albareti, Franco D.; Allende Prieto, Carlos; Almeida, Andres; Alonso-García, Javier; Anders, Friedrich; Anderson, Scott F.; Andrews, Brett et al.
Source: check_circle
NASA Astrophysics Data System

Gaia Assorted Mass Binaries Long Excluded from SLoWPoKES (GAMBLES): Identifying Ultra-wide Binary Pairs with Components of Diverse Mass

The Astronomical Journal
2017-06 | Journal article
DOI: 10.3847/1538-3881/aa6d55
BIBCODE: 2017AJ....153..259O
ARXIV: 1611.07883
Contributors: Oelkers, Ryan J.; Stassun, Keivan G.; Dhital, Saurav
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

KELT-18b: Puffy Planet, Hot Host, Probably Perturbed

The Astronomical Journal
2017-06 | Journal article
DOI: 10.3847/1538-3881/aa6d5d
BIBCODE: 2017AJ....153..263M
ARXIV: 1702.01657
Contributors: McLeod, Kim K.; Rodriguez, Joseph E.; Oelkers, Ryan J.; Collins, Karen A.; Bieryla, Allyson; Fulton, Benjamin J.; Stassun, Keivan G.; Gaudi, B. Scott; Penev, Kaloyan; Stevens, Daniel J. et al.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

GW150914: First Search for the Electromagnetic Counterpart of a Gravitational-wave Event by the TOROS Collaboration

The Astrophysical Journal
2016-09 | Journal article
DOI: 10.3847/2041-8205/828/2/L16
BIBCODE: 2016ApJ...828L..16D
ARXIV: 1607.07850
Contributors: Díaz, Mario C.; Beroiz, Martín; Peñuela, Tania; Macri, Lucas M.; Oelkers, Ryan J.; Yuan, Wenlong; García Lambas, Diego; Cabral, Juan; Colazo, Carlos; Domínguez, Mariano et al.
Source: check_circle
NASA Astrophysics Data System
grade
Preferred source (of 2)‎

A WIDE-FIELD SURVEY FOR TRANSITING HOT JUPITERS AND ECLIPSING PRE-MAIN-SEQUENCE BINARIES IN YOUNG STELLAR ASSOCIATIONS

The Astronomical Journal
2016-09-06 | Journal article | Author
DOI: 10.3847/0004-6256/152/3/75
Part of ISSN: 1538-3881
Contributors: Ryan J. Oelkers; Lucas Macri; Jennifer L. Marshall; Darren L. DePoy; Diego G. Lambas; Carlos Colazo; Katelyn Stringer
Source: Self-asserted source
Ryan J. Oelkers
grade
Preferred source (of 3)‎

LOCALIZATION AND BROADBAND FOLLOW-UP OF THE GRAVITATIONAL-WAVE TRANSIENT GW150914

The Astrophysical Journal Letters
2016-07-20 | Journal article
DOI: 10.3847/2041-8205/826/1/l13
Part of ISSN: 2041-8205
Part of ISSN: 2041-8213
Contributors: B. P. Abbott; R. Abbott; T. D. Abbott; M. R. Abernathy; F. Acernese; K. Ackley; C. Adams; T. Adams; P. Addesso; R. X. Adhikari et al.
Source: Self-asserted source
Ryan J. Oelkers

STELLAR VARIABILITY AND FLARE RATES FROM DOME A, ANTARCTICA, USING 2009 AND 2010 CSTAR OBSERVATIONS

The Astronomical Journal
2016-06-01 | Journal article
DOI: 10.3847/0004-6256/151/6/166
Part of ISSN: 0004-6256
Part of ISSN: 1538-3881
Contributors: Ryan J. Oelkers; Lucas Macri; Lifan Wang; Michael C. B. Ashley; Xiangqun Cui; Long-Long Feng; Xuefei Gong; Jon S. Lawrence; Liu Qiang; Daniel Luong-Van et al.
Source: Self-asserted source
Ryan J. Oelkers

A Wide Angle Survey of Young Stellar Associations for Hot Jupiters and Pre-Main Sequence Binaries

American Astronomical Society Meeting Abstracts #227
2016-01 | Conference abstract
BIBCODE: 2016AAS...22720502O
Contributors: Oelkers, Ryan J.; Macri, Lucas M.; Marshall, Jennifer L.; Depoy, Darren L.; Garcia Lambas, Diego
Source: check_circle
NASA Astrophysics Data System

Difference Image Analysis of Defocused Observations With CSTAR

The Astronomical Journal
2015-02 | Journal article
DOI: 10.1088/0004-6256/149/2/50
BIBCODE: 2015AJ....149...50O
ARXIV: 1410.4544
Contributors: Oelkers, Ryan J.; Macri, Lucas M.; Wang, Lifan; Ashley, Michael C. B.; Cui, Xiangqun; Feng, Long-Long; Gong, Xuefei; Lawrence, Jon S.; Qiang, Liu; Luong-Van, Daniel et al.
Source: check_circle
NASA Astrophysics Data System

VizieR Online Data Catalog: Photometry of 105 variable stars from CSTAR (Oelkers+, 2015)

VizieR Online Data Catalog
2015-02 | Dataset
BIBCODE: 2015yCat..51490050O
Contributors: Oelkers, R. J.; Macri, L. M.; Wang, L.; Ashley, M. C. B.; Cui, X.; Feng, L. -L.; Gong, X.; Lawrence, J. S.; Qiang, L.; Luong-van, D. et al.
Source: check_circle
NASA Astrophysics Data System

The TOROS Project

The Third Hot-wiring the Transient Universe Workshop
2014 | Conference paper
BIBCODE: 2014htu..conf..225D
Contributors: Diaz, M. C.; Benacquista, M.; Belczynski, K.; Branchesi, M.; Brocato, E.; DePoy, D. L.; Diaz, M. C.; Dominguez, M.; Garcia Lambas, D.; Macri, L. M. et al.
Source: check_circle
NASA Astrophysics Data System

The K2-TESS Stellar Properties Catalog

arXiv e-prints
2014-10 | Working paper
DOI: 10.48550/arXiv.1410.6379
BIBCODE: 2014arXiv1410.6379S
ARXIV: 1410.6379
Contributors: Stassun, Keivan G.; Pepper, Joshua A.; Oelkers, Ryan; Paegert, Martin; De Lee, Nathan; Sanchis-Ojeda, Roberto
Source: check_circle
NASA Astrophysics Data System

KELT-6b: A P ~ 7.9 Day Hot Saturn Transiting a Metal-poor Star with a Long-period Companion

The Astronomical Journal
2014-02 | Journal article
DOI: 10.1088/0004-6256/147/2/39
BIBCODE: 2014AJ....147...39C
ARXIV: 1308.2296
Contributors: Collins, Karen A.; Eastman, Jason D.; Beatty, Thomas G.; Siverd, Robert J.; Gaudi, B. Scott; Pepper, Joshua; Kielkopf, John F.; Johnson, John Asher; Howard, Andrew W.; Fischer, Debra A. et al.
Source: check_circle
NASA Astrophysics Data System

Difference Image Analysis of De-Focused 2009 CSTAR Observations

American Astronomical Society Meeting Abstracts #223
2014-01 | Conference abstract
BIBCODE: 2014AAS...22325521O
Contributors: Oelkers, Ryan J.; Macri, L. M.; Wang, L.; PLATO; CSTAR
Source: check_circle
NASA Astrophysics Data System

Difference Image Analysis of 2009 CSTAR Observations from Dome A in Antarctica

American Astronomical Society Meeting Abstracts #221
2013-01 | Conference abstract
BIBCODE: 2013AAS...22135223O
Contributors: Oelkers, Ryan J.; Wang, L.; Zhou, J.; Macri, L. M.; CSTAR; PLATO
Source: check_circle
NASA Astrophysics Data System

The Statistical Significance of Planetary Transit and Occultation Detections at Dome A in Antarctica

American Astronomical Society Meeting Abstracts #219
2012-01 | Conference abstract
BIBCODE: 2012AAS...21924506O
Contributors: Oelkers, Ryan J.; DePoy, D.
Source: check_circle
NASA Astrophysics Data System
How many people are using ORCID?