737 results on '"Guinan, E."'
Search Results
2. Health professionals’ perceptions of prehabilitation before haematopoietic cell transplantation to optimise candidacy in older adults
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Guinan, E., Heuston, C., Sheill, G., Chonghaile, M. Ní, and Orfali, N.
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- 2024
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3. ALMA and VLA reveal the lukewarm chromospheres of the nearby red supergiants Antares and Betelgeuse
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O'Gorman, E., Harper, G. M., Ohnaka, K., Feeney-Johansson, A., Wilkeneit-Braun, K., Brown, A., Guinan, E. F., Lim, J., Richards, A. M. S., Ryde, N., and Vlemmings, W. H. T.
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Astrophysics - Solar and Stellar Astrophysics - Abstract
We first present spatially resolved ALMA and VLA continuum observations of the early-M red supergiant Antares to search for the presence of a chromosphere at radio wavelengths. We resolve the free-free emission of the Antares atmosphere at 11 unique wavelengths between 0.7 mm (ALMA band 8) and 10 cm (VLA S band). The projected angular diameter is found to continually increase with increasing wavelength, from a low of 50.7 mas at 0.7 mm up to a diameter of 431 mas at 10 cm, which corresponds to 1.35 and 11.6 times the photospheric angular diameter, respectively. All four ALMA measurements show that the shape of the atmosphere is elongated, with a flattening of 15% at a similar position angle. The disk-averaged gas temperature of the atmosphere initially rises from a value of 2700 K at 1.35 $R_{\star}$ (i.e., 0.35 $R_{\star}$ above the photosphere) to a peak value of 3800 K at $\sim$2.5 $R_{\star}$, after which it then more gradually decreases to 1650 K at 11.6 $R_{\star}$. The rise in gas temperature between 1.35 $R_{\star}$ and $\sim$2.5 $R_{\star}$ is evidence for a chromospheric temperature rise above the photosphere of a red supergiant. We detect a clear change in the spectral index across the sampled wavelength range, with the flux density ${S_{\nu}} \propto {\nu}^{1.42}$ between 0.7 mm and 1.4 cm, which we associate with chromosphere-dominated emission, while the flux density ${S_{\nu}} \propto {\nu}^{0.8}$ between 4.3 cm and 10 cm, which we associate with wind-dominated emission. We then perform nonlocal thermal equilibrium modeling of the far-ultraviolet radiation field of another early-M red supergiant, Betelgeuse, and find that an additional hot (i.e., $>7000$ K) chromospheric photoionization component with a much smaller filling factor must also exist throughout the chromospheres of these stars., Comment: 12 pages, 6 figures, accepted for publication in A&A
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- 2020
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4. Stellar activity analysis of Barnard's Star: Very slow rotation and evidence for long-term activity cycle
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Toledo-Padrón, B., Hernández, J. I. González, Rodríguez-López, C., Mascareño, A. Suárez, Rebolo, R., Butler, R. P., Ribas, I., Anglada-Escudé, G., Johnson, E. N., Reiners, A., Caballero, J. A., Quirrenbach, A., Amado, P. J., Béjar, V. J. S., Morales, J. C., Perger, M., Jeffers, S. V., Vogt, S., Teske, J., Shectman, S., Crane, J., Díaz, M., Arriagada, P., Holden, B., Burt, J., Rodríguez, E., Herrero, E., Murgas, F., Pallé, E., Morales, N., López-González, M. J., Alonso, E. Díez, Tuomi, M., Kiraga, M., Engle, S. G., Guinan, E. F., Strachan, J. B. P., Aceituno, F. J., Aceituno, J., Casanova, V. M., Martín-Ruiz, S., Montes, D., Ortiz, J. L., Sota, A., Briol, J., Barbieri, L., Cervini, I., Deldem, M., Dubois, F., Hambsch, F. -J., Harris, B., Kotnik, C., Logie, L., Lopez, J., McNeely, M., Ogmen, Y., Pérez, L., Rau, S., Rodríguez, D., Urquijo, F. S., and Vanaverbeke, S.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The search for Earth-like planets around late-type stars using ultra-stable spectrographs requires a very precise characterization of the stellar activity and the magnetic cycle of the star, since these phenomena induce radial velocity (RV) signals that can be misinterpreted as planetary signals. Among the nearby stars, we have selected Barnard's Star (Gl 699) to carry out a characterization of these phenomena using a set of spectroscopic data that covers about 14.5 years and comes from seven different spectrographs: HARPS, HARPS-N, CARMENES, HIRES, UVES, APF, and PFS; and a set of photometric data that covers about 15.1 years and comes from four different photometric sources: ASAS, FCAPT-RCT, AAVSO, and SNO. We have measured different chromospheric activity indicators (H$\alpha$, Ca~{\sc II}~HK and Na I D), as well as the FWHM of the cross-correlation function computed for a sub-set of the spectroscopic data. The analysis of Generalized Lomb-Scargle periodograms of the time series of different activity indicators reveals that the rotation period of the star is 145 $\pm$ 15 days, consistent with the expected rotation period according to the low activity level of the star and previous claims. The upper limit of the predicted activity-induced RV signal corresponding to this rotation period is about 1 m/s. We also find evidence of a long-term cycle of 10 $\pm$ 2 years that is consistent with previous estimates of magnetic cycles from photometric time series in other M stars of similar activity levels. The available photometric data of the star also support the detection of both the long-term and the rotation signals., Comment: 16 pages, 20 figures
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- 2018
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5. A candidate super-Earth planet orbiting near the snow line of Barnard's star
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Ribas, I., Tuomi, M., Reiners, A., Butler, R. P., Morales, J. C., Perger, M., Dreizler, S., Rodríguez-López, C., Hernández, J. I. González, Rosich, A., Feng, F., Trifonov, T., Vogt, S. S., Caballero, J. A., Hatzes, A., Herrero, E., Jeffers, S. V., Lafarga, M., Murgas, F., Nelson, R. P., Rodríguez, E., Strachan, J. B. P., Tal-Or, L., Teske, J., Toledo-Padrón, B., Zechmeister, M., Quirrenbach, A., Amado, P. J., Azzaro, M., Béjar, V. J. S., Barnes, J. R., Berdiñas, Z. M., Burt, J., Coleman, G., Cortés-Contreras, M., Crane, J., Engle, S. G., Guinan, E. F., Haswell, C. A., Henning, Th., Holden, B., Jenkins, J., Jones, H. R. A., Kaminski, A., Kiraga, M., Kürster, M., Lee, M. H., López-González, M. J., Montes, D., Morin, J., Ofir, A., Pallé, E., Rebolo, R., Reffert, S., Schweitzer, A., Seifert, W., Shectman, S. A., Staab, D., Street, R. A., Mascareño, A. Suárez, Tsapras, Y., Wang, S. X., and Anglada-Escudé, G.
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
At a distance of 1.8 parsecs, Barnard's star (Gl 699) is a red dwarf with the largest apparent motion of any known stellar object. It is the closest single star to the Sun, second only to the alpha Centauri triple stellar system. Barnard's star is also among the least magnetically active red dwarfs known and has an estimated age older than our Solar System. Its properties have made it a prime target for planet searches employing techniques such as radial velocity, astrometry, and direct imaging, all with different sensitivity limits but ultimately leading to disproved or null results. Here we report that the combination of numerous measurements from high-precision radial velocity instruments reveals the presence of a low-amplitude but significant periodic signal at 233 days. Independent photometric and spectroscopic monitoring, as well as the analysis of instrumental systematic effects, show that this signal is best explained as arising from a planetary companion. The candidate planet around Barnard's star is a cold super-Earth with a minimum mass of 3.2 Earth masses orbiting near its snow-line. The combination of all radial velocity datasets spanning 20 years additionally reveals a long-term modulation that could arise from a magnetic activity cycle or from a more distant planetary object. Because of its proximity to the Sun, the proposed planet has a maximum angular separation of 220 milli-arcseconds from Barnard's star, making it an excellent target for complementary direct imaging and astrometric observations., Comment: 38 pages, 7 figures, 4 tables, author's version of published paper in Nature journal
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- 2018
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6. An Updated 2017 Astrometric Solution for Betelgeuse
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Harper, G. M., Brown, A., Guinan, E. F., O'Gorman, E., Richards, A. M. S., Kervella, P., and Decin, L.
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Astrophysics - Solar and Stellar Astrophysics - Abstract
We provide an update for the astrometric solution for the Type II supernova progenitor Betelgeuse using the revised Hipparcos Intermediate Astrometric Data (HIAD) of van Leeuwen, combined with existing VLA and new e-MERLIN and ALMA positions. The 2007 Hipparcos refined abscissa measurements required the addition of so-called Cosmic Noise of 2.4 mas to find an acceptable 5-parameter stochastic solution. We find that a measure of radio Cosmic Noise should also be included for the radio positions because surface inhomogeneities exist at a level significant enough to introduce additional intensity centroid uncertainty. Combining the 2007 HIAD with the proper motions based solely on the radio positions leads to a parallax of $\pi = 5.27\pm 0.78$ mas ($190^{+33}_{-25}$ pc), smaller than the Hipparcos 2007 value of $6.56\pm 0.83$ mas ($152^{+22}_{-17}$ pc; van Leeuwen 2007). Furthermore, combining the VLA and new e-MERLIN and ALMA radio positions with the 2007 HIAD, and including radio Cosmic Noise of 2.4 mas, leads to a nominal parallax solution of $4.51 \pm 0.80$ mas ($222^{+48}_{-34}$ pc), which while only $0.7\sigma$ different from the 2008 solution of Harper et al. it is $2.6\sigma$ different from the solution of van Leeuwen. An accurate and precise parallax for Betelgeuse is always going to be difficult to obtain because it is small compared to the stellar angular diameter ($\theta=44$ mas). We outline an observing strategy, utilizing future mm and sub-mm high-spatial resolution interferometry that must be used if substantial improvements in precision and accuracy of the parallax and distance are to be achieved.
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- 2017
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7. Nutrient Intakes and Gastrointestinal Symptoms Among Esophagogastric Cancer Survivors up to 5 Years Post-Surgery
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Bennett, A. E., primary, O’Neill, L., additional, Doyle, S. L., additional, Guinan, E. M., additional, O’Sullivan, J., additional, Reynolds, J. V., additional, and Hussey, J., additional
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- 2024
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8. About Exobiology: The Case for Dwarf K Stars
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Cuntz, M. and Guinan, E. F.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
One of the most fundamental topics of exobiology concerns the identification of stars with environments consistent with life. Although it is believed that most types of main-sequence stars might be able to support life, particularly extremophiles, special requirements appear to be necessary for the development and sustainability of advanced life forms. From our study, orange main-sequence stars, ranging from spectral type late-G to mid-K (with a maximum at early-K), are most promising. Our analysis considers a variety of aspects, including (1) the frequency of the various types of stars, (2) the speed of stellar evolution their lifetimes, (3) the size of the stellar climatological habitable zones (CLI-HZs), (4) the strengths and persistence of their magnetic dynamo generated X-ray - UV emissions, and (5) the frequency and severity of flares, including superflares; both (4) and (5) greatly reduce the suitability of red dwarfs to host life-bearing planets. The various phenomena show pronounced dependencies on the stellar key parameters such as effective temperature and mass, permitting the assessment of the astrobiological significance of various types of stars. Thus, we developed a "Habitable-Planetary-Real-Estate Parameter" (HabPREP) that provides a measure for stars that are most suitable for planets with life. Early K stars are found to have the highest HabPREP values, indicating they may be "Goldilocks" stars for life-hosting planets. Red dwarfs are numerous, having long lifetimes, but their narrow CLI-HZs and hazards from magnetic activity make them less suitable for hosting exolife. Moreover, we provide X-ray - FUV irradiances for G0 V - M5 V stars over a wide range of ages., Comment: 26 pages, 4 figures, 3 tables; accepted by The Astrophysical Journal
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- 2016
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9. Magnetic field and wind of Kappa Ceti: towards the planetary habitability of the young Sun when life arose on Earth
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Nascimento Jr., J. -D. do, Vidotto, A. A., Folsom, P. Petit C., Castro, M., Marsden, S. C., Morin, J., de Mello, G. F. Porto, Meibom, S., Jeffers, S. V., Guinan, E., and Ribas, I.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
We report magnetic field measurements for Kappa1~Cet, a proxy of the young Sun when life arose on Earth. We carry out an analysis of the magnetic properties determined from spectropolarimetric observations and reconstruct its large-scale surface magnetic field to derive the magnetic environment, stellar winds and particle flux permeating the interplanetary medium around Kappa1~Cet. Our results show a closer magnetosphere and mass-loss rate of Mdot = 9.7 x 10^{-13} Msol/yr, i.e., a factor 50 times larger than the current solar wind mass-loss rate, resulting in a larger interaction via space weather disturbances between the stellar wind and a hypothetical young-Earth analogue, potentially affecting the planet's habitability. Interaction of the wind from the young Sun with the planetary ancient magnetic field may have affected the young Earth and its life conditions, Comment: 6 pages, 5 figures, Published at the Astrophysical Journal Letters (ApJL): Manuscript #LET33582
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- 2016
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10. Revised physical elements of the astrophysically important O9.5+O9.5V eclipsing binary system Y Cyg
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Harmanec, P., Holmgren, D. E., Wolf, M., Božić, H., Guinan, E. F., Kang, Y. W., Mayer, P., McCook, G. P., Nemravová, J., Yang, S., Šlechta, M., Ruždjak, D., Sudar, D., and Svoboda, P.
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Astrophysics - Solar and Stellar Astrophysics - Abstract
Thanks to its long and rich observational history and rapid apsidal motion, the massive eclipsing binary Y Cyg represents one of the cornestones to critical tests of stellar evolution theory for massive stars. Yet, the determination of the basic physical properties is less accurate than it could be given the existing number of spectral and photometric observations. Our goal is to analyze all these data simultaneously with the new dedicated series of our own spectral and photometric observations from observatories widely separated in longitude. We obtained new series of UBV observations at three observatories separated in local time to obtain complete light curves of Y Cyg for its orbital period close to 3 days. This new photometry was reduced and carefully transformed to the standard UBV system using the HEC22 program. We also obtained new series of red spectra secured at two observatories and re-analyzed earlier obtained blue electronic spectra. Our analyses provide the most accurate so far published value of the apsidal period of 47.805 +/- 0.030 yrs and the following physical elements: M1=17.72+/-0.35$ Msun, M2=17.73+/-0.30 Msun, R1=5.785+/-0.091 Rsun, and R2=5.816+/-0.063 Rsun. The disentangling thus resulted in the masses, which are somewhat higher than all previous determinations and virtually the same for both stars, while the light curve implies a slighly higher radius and luminosity for star 2. The above empirical values imply the logarithm of the internal structure constant log k2 = -1.937. A comparison with Claret's stellar interior models implies an age close to 2 millions yrs for both stars. The claimed accuracy of modern element determination of 1-2 per cent seems still a bit too optimistic and obtaining new high-dispersion and high-resolution spectra is desirable., Comment: 13 pages; accepted for publication in Astronomy and Astrophysics
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- 2014
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11. Cardiopulmonary Exercise Testing in Oesophagogastric Surgery: a Systematic Review
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Sheill, G., Reynolds, S., O’Neill, L., Mockler, D., Reynolds, J. V., Hussey, J., and Guinan, E.
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- 2020
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12. The Behavior of the Paschen and Calcium Triplet Lines in Cepheid Variables II : The 16-day Variable X Cygni
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Wallerstein, G., Anderson, R. I., Farrell, E. M., Guinan, E., Albright, M., Lacy, B., Davis, C. E., Ritchey, A., Eyer, L., and Mowlavi, N.
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- 2019
13. High-resolution spectropolarimetric of k Cet: A proxy for the young Sun
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Nascimento Jr., J. D. do, Petit, P., Marsden, S., de Mello, G. F. Porto, Ribas, I., Jeffers, S., Castro, M., Guinan, E., and Collaboration, the Bcool
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Astrophysics - Solar and Stellar Astrophysics - Abstract
Among the solar proxies studied in the Sun in Time k Cet (HD 20630) stands out as potentially having a mass very close to solar and a young age. On this study, we monitored the magnetic field and the chromospheric activity from the Ca II H & K lines of k Cet. We used the Least-Square-Deconvolution (LSD, Donati et al. 1997) by simultaneously extracting the information contained in all 8,000 photospheric lines of the echelogram (K1 type star). To reconstruct a reliable magnetic map and characterize the surface differential rotation of k Cet we used 14 exposures spread over 2 months, in order to cover at least two rotational cycles (Prot ~ 9.2 days). The LSD technique was applied to detect the Zeeman signature of the magnetic field in each of our 14 observations and to measure its longitudinal component. In order to reconstruct the magnetic field geometry of k Cet, we applied the Zeeman Doppler Imaging (ZDI) inversion method. ZDI revealed a structure in the radial magnetic field consisting of a polar magnetic spot. On this study, we present the fisrt look results of a high-resolution spectropolarimetric campaign to characterize the activity and the magnetic fields of this young solar proxy., Comment: 2 pages, 2 figures
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- 2013
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14. Optimizing exoplanet transit searches around low-mass stars with inclination constraints
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Herrero, E., Ribas, I., Jordi, C., Guinan, E. F., and Engle, S. G.
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Aims. We investigate a method to increase the efficiency of a targeted exoplanet search with the transit technique by preselecting a subset of candidates from large catalogs of stars. Assuming spin-orbit alignment, this can be done by considering stars that have higher probability to be oriented nearly equator-on (inclination close to 90^{\circ}). Methods. We use activity-rotation velocity relations for low-mass stars with a convective envelope to study the dependence of the position in the activity-vsini diagram on the stellar axis inclination. We compose a catalog of G-, K-, M-type main sequence simulated stars using isochrones, an isotropic inclination distribution and empirical relations to obtain their rotation periods and activity indexes. Then the activity - vsini diagram is filled and statistics are applied to trace the areas containing the higher ratio of stars with inclinations above 80^{\circ}. A similar statistics is applied to stars from real catalogs with log(R'HK) and vsini data to find their probability of being equator-on. Results. We present the method used to generate the simulated star catalog and the subsequent statistics to find the highly inclined stars from real catalogs using the activity - vsini diagram. Several catalogs from the literature are analysed and a subsample of stars with the highest probability of being equator-on is presented. Conclusions. Assuming spin-orbit alignment, the efficiency of an exoplanet transit search in the resulting subsample of probably highly inclined stars is estimated to be two to three times higher than with a global search with no preselection., Comment: Accepted by A&A, 10 pages, 4 figures
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- 2011
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15. RACE-OC Project: Rotation and variability in the epsilon Chamaeleontis, Octans, and Argus stellar associations
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Messina, S., Desidera, S., Lanzafame, A. C., Turatto, M., and Guinan, E. F.
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Astrophysics - Solar and Stellar Astrophysics - Abstract
We aim at determining the rotational and magnetic-related activity properties of stars at different stages of evolution. We focus our attention primarily on members of young stellar associations of known ages. Specifically, we extend our previous analysis in Paper I (Messina et al. 2010, A&A 520, A15) to 3 additional young stellar associations beyond 100 pc and with ages in the range 6-40 Myr: epsilon Chamaeleontis (~6 Myr), Octans (~20 Myr), and Argus (~40 Myr). Additional rotational data of eta Chamaeleontis and IC2391 clusters are also considered. Rotational periods were determined from photometric time-series data obtained by the All Sky Automated Survey (ASAS) and the Wide Angle Search for Planets (SuperWASP) archives. With the present study we have completed the analysis of the rotational properties of the late-type members of all known young loose associations in the solar neighborhood. Considering also the results of Paper I, we have derived the rotation periods of 241 targets: 171 confirmed, 44 likely, 26 uncertain. The period of the remaining 50 stars known to be part of loose associations still remains unknown. This rotation period catalogue, and specifically the new information presented in this paper at ~6, 20, and 40 Myr, contributes significantly to a better observational description of the angular momentum evolution of young stars., Comment: Accepted by Astronomy & Astrophysics. Onlines figures will be available at CDS
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- 2011
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16. YSOVAR: the first sensitive, wide-area, mid-IR photometric monitoring of the ONC
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Morales-Calderón, M., Stauffer, J. R., Hillenbrand, L. A., Gutermuth, R., Song, I., Rebull, L. M., Plavchan, P., Carpenter, J. M., Whitney, B. A., Covey, K., de Oliveira, C. Alves, Winston, E., McCaughrean, M. J., Bouvier, J., Guieu, S., Vrba, F. J., Holtzman, J., Marchis, F., Hora, J. L., Wasserman, L. H., Terebey, S., Megeath, T., Guinan, E., Forbrich, J., Huélamo, N., Riviere-Marichalar, P., Barrado, D., Stapelfeldt, K., Hernández, J., Allen, L. E., Ardila, D. R., Bayo, A., Favata, F., James, D., Werner, M., and Wood, K.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
We present initial results from time series imaging at infrared wavelengths of 0.9 sq. degrees in the Orion Nebula Cluster (ONC). During Fall 2009 we obtained 81 epochs of Spitzer 3.6 and 4.5 micron data over 40 consecutive days. We extracted light curves with ~3% photometric accuracy for ~2000 ONC members ranging from several solar masses down to well below the hydrogen burning mass limit. For many of the stars, we also have time-series photometry obtained at optical (Ic) and/or near-infrared (JKs) wavelengths. Our data set can be mined to determine stellar rotation periods, identify new pre-main-sequence (PMS) eclipsing binaries, search for new substellar Orion members, and help better determine the frequency of circumstellar disks as a function of stellar mass in the ONC. Our primary focus is the unique ability of 3.6 & 4.5 micron variability information to improve our understanding of inner disk processes and structure in the Class I and II young stellar objects (YSOs). In this paper, we provide a brief overview of the YSOVAR Orion data obtained in Fall 2009, and we highlight our light curves for AA-Tau analogs - YSOs with narrow dips in flux, most probably due to disk density structures passing through our line of sight. Detailed follow-up observations are needed in order to better quantify the nature of the obscuring bodies and what this implies for the structure of the inner disks of YSOs., Comment: Accepted to ApJ
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- 2011
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17. Searching for Weak or Complex Magnetic Fields in Polarized Spectra of Rigel
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Shultz, M., Wade, G. A., Neiner, C., Manset, N., Petit, V., Grunhut1, J., Guinan, E., Hanes, D., and Collaboration, the MiMeS
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Astrophysics - Solar and Stellar Astrophysics - Abstract
Seventy-eight high-resolution Stokes V, Q and U spectra of the B8Iae supergiant Rigel were obtained with the ESPaDOnS spectropolarimeter at CFHT and its clone NARVAL at TBL in the context of the Magnetism in Massive Stars (MiMeS) Large Program, in order to scrutinize this core-collapse supernova progenitor for evidence of weak and/or complex magnetic fields. In this paper we describe the reduction and analysis of the data, the constraints obtained on any photospheric magnetic field, and the variability of photospheric and wind lines., Comment: IAUS272 - Active OB Stars: Structure, Evolution, Mass Loss and Critical Limits
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- 2010
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18. X-Ray, FUV, and UV Observations of alpha Centauri B: Determination of Long-term Magnetic Activity Cycle and Rotation Period
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DeWarf, L. E., Datin, K. M., and Guinan, E. F.
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Astrophysics - Solar and Stellar Astrophysics - Abstract
We have been carrying out a study of stellar magnetic activity, dynamos, atmospheric physics, and spectral irradiances from a sample of solar-type G0-5 V stars with different ages. One of the major goals of this program is to study the evolution of the Sun's X-ray through NUV spectral irradiances with age. Of particular interest is the determination of the young Sun's elevated levels of high-energy fluxes because of the critical roles that X-ray through FUV emissions play on the photochemical and photoionization evolution of early, young planetary atmospheres and ionospheres. Motivated by the current exoplanetary search missions that are hunting for earth-size planets in the habitable zones of nearby main-sequence G-M stars, we are expanding our program to cooler, less luminous, but much more numerous main-sequence K-type stars, such as alpha Centauri B. The long life (2-3x longer than our Sun) and slow evolution of K stars provide nearly constant energy sources for possible hosted planets. Presented here are X-ray, UV, and recently acquired FUV observations of the K1 V star alpha Cen B. These combined high-energy measures provide a more complete look into the nature of alpha Cen B's magnetic activity and X-UV radiances. We find that alpha Cen B has exhibited significant long-term variability in X-ray through NUV emission fluxes, indicating a solar-like long-term activity cycle of P_cycle = 8.84 years. In addition, analysis of the short-term rotational modulation of mean light due to the effects of magnetically active regions has yielded a well-determined rotation period of P_rotation = 36.2 days. alpha Cen B is the only old main-sequence K star with a reliably determined age and rotation period, and for early K-stars, is an important calibrator for stellar age/rotation/activity relations.
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- 2010
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19. RACE-OC Project: Rotation and variability in young stellar associations within 100 pc
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Messina, S., Desidera, S., Turatto, M., Lanzafame, A. C., and Guinan, E. F.
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Astrophysics - Solar and Stellar Astrophysics - Abstract
Our goal is to determine the rotational and magnetic-related activity properties of stars at different stages of evolution. We have focussed our attention on 6 young loose stellar associations within 100 pc and ages in the range 8-70 Myr: TW Hydrae (~8 Myr), beta Pictoris (~10 Myr), Tucana/Horologium, Columba, Carina (~30 Myr), and AB Doradus (~70 Myr). Additional data on alpha Persei and the Pleiades from the literature is also considered. Rotational periods of stars showing rotational modulation due to photospheric magnetic activity (i.e. starspots) have been determined applying the Lomb-Scargle periodogram technique to photometric time-series obtained by the All Sky Automated Survey (ASAS). The magnetic activity level has been derived from the amplitude of the V lightcurves. We detected the rotational modulation and measured the rotation periods of 93 stars for the first time, and confirmed the periods of 41 stars already known from the literature. For further 10 stars we revised the period determinations by other authors. The sample was augmented with periods of 21 additional stars retrieved from the literature. In this way, for the first time we were able to determine largest set of rotation periods at ages of ~8, ~10 and ~30 Myr, as well as increase by 150\% the number of known periodic members of AB Dor.The analysis of the rotation periods in young stellar associations, supplemented by Orion Nebula Cluster (ONC) and NGC2264 data from the literature, has allowed us to find that in the 0.6 - 1.2 solar masses range the most significant variations of the rotation period distribution are the spin-up between 9 and 30 Myr and the spin-down between 70 and 110 Myr. Variations between 30 and 70 Myr are rather doubtful, despite the median period indicates a significant spin-up., Comment: Accepted by Astronomy and Astrophysics
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- 2010
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20. A multi-wavelength study of the young star V1118 Orionis in outburst
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Audard, M., Stringfellow, G. S., Güdel, M., Skinner, S. L., Walter, F. M., Guinan, E. F., Hamilton, R. T., Briggs, K. R., and Baldovin-Saavedra, C.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
Abriged version for astroph: The young late-type star V1118 Orionis was in outburst from 2005 to 2006. We followed the outburst with optical and near-infrared photometry; the X-ray emission was further probed with observations taken with XMM-Newton and Chandra during and after the outburst. In addition, we obtained mid-infrared photometry and spectroscopy with Spitzer at the peak of the outburst and in the post-outburst phase. The spectral energy distribution of V1118 Ori varied significantly over the course of the outburst. The optical flux showed the largest variations, most likely due to enhanced emission by a hot spot. The latter dominated the optical and near-infrared emission at the peak of the outburst, while the disk emission dominated in the mid-infrared. The X-ray flux correlated with the optical and infrared fluxes, indicating that accretion affected the magnetically active corona and the stellar magnetosphere. The thermal structure of the corona was variable with some indication of a cooling of the coronal temperature in the early phase of the outburst with a gradual return to normal values. Color-color diagrams in the optical and infrared showed variations during the outburst, with no obvious signature of reddening due to circumstellar matter. Using MC realizations of star+disk+hotspot models to fit the SED in ``quiescence'' and at the peak of the outburst, we determined that the mass accretion rate varied from about 2.5E-7 Msun/yr to 1E-6 Msun/yr; in addition the fractional area of the hotspot increased significantly as well. The multi-wavelength study of the V1118 Ori outburst helped us to understand the variations in spectral energy distributions and demonstrated the interplay between the disk and the stellar magnetosphere in a young, strongly accreting star., Comment: Accepted in A&A, Tables will be published online
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- 2009
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21. The distance to the Andromeda Galaxy from eclipsing binaries
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Vilardell, F., Ribas, I., Jordi, C., Fitzpatrick, E. L., and Guinan, E. F.
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Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
The cosmic distance scale largely depends on distance determinations to Local Group galaxies. In this sense, the Andromeda Galaxy (M31) is a key rung to better constrain the cosmic distance ladder. A project was started in 1999 to firmly establish a direct and accurate distance to M31 using eclipsing binaries (EBs). After the determination of the first direct distance to M31 from EBs, the second direct distance to an EB system is presented: M31V_J00443610+4129194. Light and radial velocity curves were obtained and fitted to derive the masses and radii of the components. The acquired spectra were combined and disentangled to determine the temperature of the components. The analysis of the studied EB resulted in a distance determination to M31 of (m-M)o = 24.30 +/- 0.11 mag. This result, when combined with the previous distance determination to M31, results in a distance modulus of (m-M)o = 24.36 +/- 0.08 mag (744 +/- 33 kpc), fully compatible with other distance determinations to M31. With an error of only 4%, the obtained value firmly establishes the distance to this important galaxy and represents the fulfillment of the main goal of our project., Comment: 7 pages, 3 figures, accepted for publication in A&A (Nov 6, 2009)
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- 2009
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22. Biological Damage due to Photospheric, Chromospheric and Flare Radiation in the Environments of Main-Sequence Stars
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Cuntz, M., Guinan, E. F., and Kurucz, R. L.
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
We explore the biological damage initiated in the environments of F, G, K, and M-type main-sequence stars due to photospheric, chromospheric and flare radiation. The amount of chromospheric radiation is, in a statistical sense, directly coupled to the stellar age as well as the presence of significant stellar magnetic fields and dynamo activity. With respect to photospheric radiation, we also consider detailed synthetic models, taking into account millions or hundred of millions of lines for atoms and molecules. Chromospheric UV radiation is increased in young stars in regard to all stellar spectral types. Flare activity is most pronounced in K and M-type stars, which also has the potential of stripping the planetary atmospheres of close-in planets, including planets located in the stellar habitable zone. For our studies, we take DNA as a proxy for carbon-based macromolecules, guided by the paradigm that carbon might constitute the biochemical centerpiece of extraterrestrial life forms. Planetary atmospheric attenuation is considered in an approximate manner., Comment: 8 pages, 4 figues, Planetary Systems as Potential Sites for Life, Invited Paper, IAU Symposium 264, eds. A. Kosovichev et al. (San Francisco: Astr. Soc. Pac.), in press
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- 2009
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23. Fully Automated Approaches to Analyze Large-Scale Astronomy Survey Data
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Prsa, A., Guinan, E. F., Devinney, E. J., Engle, S. G., DeGeorge, M., McCook, G. P., Maurone, P. A., Pepper, J., James, D. J., Bradstreet, D. H., Alcock, C. R., Devor, J., Seaman, R., Zwitter, T., Long, K., Wilson, R. E., Ribas, I., and Gimenez, A.
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Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Galaxy Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Observational astronomy has changed drastically in the last decade: manually driven target-by-target instruments have been replaced by fully automated robotic telescopes. Data acquisition methods have advanced to the point that terabytes of data are flowing in and being stored on a daily basis. At the same time, the vast majority of analysis tools in stellar astrophysics still rely on manual expert interaction. To bridge this gap, we foresee that the next decade will witness a fundamental shift in the approaches to data analysis: case-by-case methods will be replaced by fully automated pipelines that will process the data from their reduction stage, through analysis, to storage. While major effort has been invested in data reduction automation, automated data analysis has mostly been neglected despite the urgent need. Scientific data mining will face serious challenges to identify, understand and eliminate the sources of systematic errors that will arise from this automation. As a special case, we present an artificial intelligence (AI) driven pipeline that is prototyped in the domain of stellar astrophysics (eclipsing binaries in particular), current results and the challenges still ahead., Comment: 10 pages; Decadal Survey 2010 White Paper on Theory, Computation, and Laboratory Astrophysics
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- 2009
24. Absolute properties of the low-mass eclipsing binary CM Draconis
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Morales, J. C., Ribas, I., Jordi, C., Torres, G., Gallardo, J., Guinan, E. F., Charbonneau, D., Wolf, M., Latham, D. W., Anglada-Escudé, G., Bradstreet, D. H., Everett, M. E., O'Donovan, F. T., Mandushev, G., and Mathieu, R. D.
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Astrophysics - Abstract
Spectroscopic and eclipsing binary systems offer the best means for determining accurate physical properties of stars, including their masses and radii. The data available for low-mass stars have yielded firm evidence that stellar structure models predict smaller radii and higher effective temperatures than observed, but the number of systems with detailed analyses is still small. In this paper we present a complete reanalysis of one of such eclipsing systems, CM Dra, composed of two dM4.5 stars. New and existing light curves as well as a radial velocity curve are modeled to measure the physical properties of both components. The masses and radii determined for the components of CM Dra are M1=0.2310+/-0.0009 Msun, M2=0.2141+/-0.0010 Msun, R1=0.2534+/-0.0019 Rsun, and R2=0.2396+/-0.0015 Rsun. With relative uncertainties well below the 1% level, these values constitute the most accurate properties to date for fully convective stars. This makes CM Dra a valuable benchmark for testing theoretical models. In comparing our measurements with theory, we confirm the discrepancies reported previously for other low-mass eclipsing binaries. These discrepancies seem likely to be due to the effects of magnetic activity. We find that the orbit of this system is slightly eccentric, and we have made use of eclipse timings spanning three decades to infer the apsidal motion and other related properties., Comment: 19 pages, 9 figures. Accepted for publication in ApJ
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- 2008
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25. In search of RR Lyrae type stars in eclipsing binary systems. OGLE052218.07-692827.4: an optical blend
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Prsa, A., Guinan, E. F., Devinney, E. J., and Engle, S. G.
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Astrophysics - Abstract
During the OGLE-2 operation, Soszynski et al. (2003) found 3 LMC candidates for an RR Lyr-type component in an eclipsing binary system. Two of those have orbital periods that are too short to be physically plausible and hence have to be optical blends. For the third, OGLE052218.07-692827.4, we developed a model of the binary that could host the observed RR Lyr star. After being granted HST/WFPC2 time, however, we were able to resolve 5 distinct sources within a 1.3" region that is typical of OGLE resolution, proving that OGLE052218.07-692827.4 is also an optical blend. Moreover, the putative eclipsing binary signature found in the OGLE data does not seem to correspond to a physically plausible system; the source is likely another background RR Lyr star. There are still no RR Lyr stars discovered so far in an eclipsing binary system., Comment: 4 pages, accepted to A&A
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- 2008
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26. Artificial Intelligence Approach to the Determination of Physical Properties of Eclipsing Binaries. I. The EBAI Project
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Prsa, A., Guinan, E. F., Devinney, E. J., DeGeorge, M., Bradstreet, D. H., Giammarco, J. M., Alcock, C. R., and Engle, S. G.
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Astrophysics - Abstract
Achieving maximum scientific results from the overwhelming volume of astronomical data to be acquired over the next few decades will demand novel, fully automatic methods of data analysis. Artificial intelligence approaches hold great promise in contributing to this goal. Here we apply neural network learning technology to the specific domain of eclipsing binary (EB) stars, of which only some hundreds have been rigorously analyzed, but whose numbers will reach millions in a decade. Well-analyzed EBs are a prime source of astrophysical information whose growth rate is at present limited by the need for human interaction with each EB data-set, principally in determining a starting solution for subsequent rigorous analysis. We describe the artificial neural network (ANN) approach which is able to surmount this human bottleneck and permit EB-based astrophysical information to keep pace with future data rates. The ANN, following training on a sample of 33,235 model light curves, outputs a set of approximate model parameters (T2/T1, (R1+R2)/a, e sin(omega), e cos(omega), and sin i) for each input light curve data-set. The whole sample is processed in just a few seconds on a single 2GHz CPU. The obtained parameters can then be readily passed to sophisticated modeling engines. We also describe a novel method polyfit for pre-processing observational light curves before inputting their data to the ANN and present the results and analysis of testing the approach on synthetic data and on real data including fifty binaries from the Catalog and Atlas of Eclipsing Binaries (CALEB) database and 2580 light curves from OGLE survey data. [abridged], Comment: 52 pages, accepted to ApJ
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- 2008
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27. Astrobiological Effects of F, G, K and M Main-Sequence Stars
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Cuntz, M., Gurdemir, L., Guinan, E. F., and Kurucz, R. L.
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Astrophysics - Abstract
We focus on the astrobiological effects of photospheric radiation produced by main-sequence stars of spectral types F, G, K, and M. The photospheric radiation is represented by using realistic spectra, taking into account millions or hundred of millions of lines for atoms and molecules. DNA is taken as a proxy for carbon-based macromolecules, assumed to be the chemical centerpiece of extraterrestrial life forms. Emphasis is placed on the investigation of the radiative environment in conservative as well as generalized habitable zones., Comment: 3 pages, 3 figures; submitted to: Exoplanets: Detection, Formation and Dynamics, IAU Symposium 249, eds. Y.S. Sun and S. Ferraz-Mello (San Francisco: Astr. Soc. Pac.)
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- 2007
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28. Astrobiology in the Environments of Main-Sequence Stars: Effects of Photospheric Radiation
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Cuntz, M., Gurdemir, L., Guinan, E. F., and Kurucz, R. L.
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Astrophysics - Abstract
We explore if carbon-based macromolecules (such as DNA) in the environments of stars other than the Sun are able to survive the effects of photospheric stellar radiation, such as UV-C. Therefore, we focus on main-sequence stars of spectral types F, G, K, and M. Emphasis is placed on investigating the radiative environment in the stellar habitable zones. Stellar habitable zones are relevant to astrobiology because they constitute circumstellar regions in which a planet of suitable size can maintain surface temperatures for water to exist in fluid form, thus increasing the likelihood of Earth-type life., Comment: 4 pages, 4 figures; submitted to: Bioastronomy 2007: Molecules, Microbes and Extraterrestrial Life, eds. K. Meech, M. Mumma, J. Siefert and D. Werthimer, A.S.P. Conf. Ser
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- 2007
29. X-Ray Spectral Variability During an Outburst in V1118 Ori
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Audard, M., Guedel, M., Skinner, S. L., Briggs, K. R., Walter, F. M., Stringfellow, G., Hamilton, R. T., and Guinan, E. F.
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Astrophysics - Abstract
We present results from a multi-wavelength campaign to monitor the 2005 outburst of the low-mass young star V1118 Ori. Although our campaign covers the X-ray, optical, infrared, and radio regimes, we focus in this Letter on the properties of the X-ray emission in V1118 Ori during the first few months after the optical outburst. Chandra and XMM-Newton detected V1118 Ori at three epochs in early 2005. The X-ray flux and luminosity stayed similar within a factor of two, and at the same level as in a pre-outburst observation in 2002. The hydrogen column density showed no evidence for variation from its modest pre-outburst value of $N_\mathrm{H} \sim 3 \times 10^{21}$ cm$^{-2}$. However, a spectral change occurred from a dominant hot plasma ($\sim 25$ MK) in 2002 and in January 2005 to a cooler plasma ($\sim 8$ MK) in February 2005 and in March 2005. We hypothesize that the hot magnetic loops high in the corona were disrupted by the closing in of the accretion disk due to the increased accretion rate during the outburst, whereas the lower cooler loops were probably less affected and became the dominant coronal component., Comment: Accepted for publication in ApJ Letters
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- 2005
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30. Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres: I. High-energy Irradiances (1-1700 A)
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Ribas, I., Guinan, E. F., Guedel, M., and Audard, M.
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Astrophysics - Abstract
We report on the results of the Sun in Time multi-wavelength program (X-rays to the UV) of solar analogs with ages covering ~0.1-7 Gyr. The chief science goals are to study the solar magnetic dynamo and to determine the radiative and magnetic properties of the Sun during its evolution across the main sequence. The present paper focuses on the latter goal, which has the ultimate purpose of providing the spectral irradiance evolution of solar-type stars to be used in the study and modeling of planetary atmospheres. The results from the Sun in Time program suggest that the coronal X-ray-EUV emissions of the young main-sequence Sun were ~100-1000 times stronger than those of the present Sun. Similarly, the transition region and chromospheric FUV-UV emissions of the young Sun are expected to be 20-60 and 10-20 times stronger, respectively, than at present. When considering the integrated high-energy emission from 1 to 1200 A, the resulting relationship indicates that the solar high-energy flux was about 2.5 times the present value 2.5 Gyr ago and about 6 times the present value about 3.5 Gyr ago (when life supposedly arose on Earth). The strong radiation emissions inferred should have had major influences on the thermal structure, photochemistry, and photoionization of planetary atmospheres and also played an important role in the development of primitive life in the Solar System. Some examples of the application of the Sun in Time results on exoplanets and on early Solar System planets are discussed., Comment: 20 pages, 8 figures, accepted for publication in ApJ
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- 2004
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31. Fundamental Properties and Distances of LMC Eclipsing Binaries: IV. HV 5936
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Fitzpatrick, E. L., Ribas, I., Guinan, E. F., Maloney, F. P., and Claret, A.
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Astrophysics - Abstract
We have determined the fundamental properties and distance of a fourth eclipsing binary system (EB) in the Large Magellanic Cloud, HV5936 (B0.5 V + B2 III). As in our previous studies, we combine "classical" EB light curve and radial velocity curve analyses with modeling of the UV-through-optical spectral energy distribution of HV5936 to produce a detailed characterization of the system. In this paper, we also include an analysis of the high-resolution optical absorption line spectra of the binary components. We find HV5936 to be an Algol-class system, in which the masses of the primary and secondary stars have evolved via mass transfer to their current values of 11.6 Mo and 4.7 Mo, respectively. The properties of the primary star are indistinguishable from those of a "normal" star of the same current mass. The secondary is found to be overluminous for its current mass and exhibits a factor-of-2 enhancement in its surface He abundance. These results are compatible with "Case A" mass exchange occurring during the core hydrogen burning phase of the current secondary. The distance derived to the system, 43.2 +/- 1.8 kpc, implies a distance of ~44.3 kpc to the optical center of the LMC. This is several kpc closer than found in our analyses of other systems and we suggest that HV5936 lies "above" the LMC disk. This is supported by the very low interstellar H I column density and low E(B-V) found for the system - both of which are consistent with expected Milky Way foreground material - and may be associated with HV5936's location near the LMC supergiant shell LMC4., Comment: 44 pages, including 8 pages of tables and 11 pages of figures. Accepted for publication in the April 20, 2003 issue of the Astrophysical Journal
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- 2003
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32. A Systematic Spectroscopic X-Ray Study of Stellar Coronae with XMM-Newton: Early Results
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Guedel, M., Audard, M., Smith, K. W., Sres, A., Escoda, C., Wehrli, R., Guinan, E. F., Ribas, I., Beasley, A. J., Mewe, R., Raassen, A. J. J., Behar, E., and Magee, H.
- Subjects
Astrophysics - Abstract
We have been conducting a comprehensive survey of stellar coronae with the XMM-Newton Reflection Grating Spectrometers during the commissioning, calibration, verification, and guaranteed time phases of the mission, accompanied by simultaneous observations with the EPIC cameras and, for several targets, with the radio VLA and/or the VLBA. The principal aim of this project is threefold: i) To understand stellar coronal structure and composition by studying systematics in the coronae of stars with widely different levels of magnetic activity; ii) to investigate heating and particle acceleration physics during flares, their role in the overall coronal energy budget, and their possible role in the quiescent stellar emission; iii) to probe stellar coronal evolution by studying solar analogs of different ages. We report early results from this project., Comment: to appear in The Twelfth Cool Stars, Stellar Systems and the Sun, eds. A. Brown, T.R. Ayres, G.M. Harper, (Boulder: Univ. of Colorado), in press
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- 2001
33. AD Leo from X-Rays to Radio: Are Flares Responsible for the Heating of Stellar Coronae?
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Guedel, M., Audard, M., Guinan, E. F., Drake, J. J., Kashyap, V. L., Mewe, R., and Alekseev, I. Y.
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Astrophysics - Abstract
In spring 1999, a long coordinated observing campaign was performed on the flare star AD Leo, including {\it EUVE}, {\it BeppoSAX}, the {\it VLA}, and optical telescopes. The campaign covered a total of 44 days. We obtained high-quality light curves displaying ongoing variability on various timescales, raising interesting questions on the role of flare-like events for coronal heating. We performed Kolmogorov-Smirnov tests to compare the observations with a large set of simulated light curves composed of statistical flares that are distributed in energy as a power law of the form ${\rm d}N/{\rm d}E \propto E^{-\alpha}$ with selectable index $\alpha$. We find best-fit $\alpha$ values slightly above a value of 2, indicating that the extension of the flare population toward small energies could be important for the generation of the overall X-ray emission., Comment: To appear in Proc. of "X-ray astronomy 2000",(Palermo Sep. 2000), Eds. R. Giacconi, L. Stella, S. Serio, ASP Conf. Series, in press
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- 2000
34. Fundamental Properties and Distances of LMC Eclipsing Binaries II. HV 982
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Fitzpatrick, E. L., Ribas, I., Guinan, E. F., DeWarf, L. E., Maloney, F. P., and Massa, D.
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Astrophysics - Abstract
We have determined the distance to a second eclipsing binary system (EB) in the Large Magellanic Cloud, HV982 (~B1 IV-V + ~B1 IV-V). The measurement of the distance -- among other properties of the system -- is based on optical photometry and spectroscopy and space-based UV/optical spectrophotometry. The analysis combines the ``classical'' EB study of light and radial velocity curves, which yields the stellar masses and radii, with a new analysis of the observed energy distribution, which yields the effective temperature, metallicity, and reddening of the system plus the distance ``attenuation factor'', essentially (radius/distance)^2. Combining the results gives the distance to HV982, which is 50.2 +/- 1.2 kpc. This distance determination consists of a detailed study of well-understood objects (B stars) in a well-understood evolutionary phase (core H burning), and is free of the biases and uncertainties that plague various other techniques. After correcting for the location of HV982, we find an implied distance to the optical center of the LMC's bar of d(LMC) = 50.7 +/- 1.2 kpc. This result differs by nearly 5 kpc from our earlier result for the EB HV2274, which implies a bar distance of 45.9 kpc. These results may reflect either marginally compatible measures of a unique LMC distance or, alternatively, suggest a significant depth to the stellar distribution in the LMC. Some evidence for this latter hypothesis is discussed., Comment: To appear in the Astrophysical Journal (January 2002) 10 pages of text, plus 5 tables and 9 figures (ApJ-emulation style). This version incorporates new observations which double the number of ground-based radial velocity measurements and extend the spectrophotometric coverage to 1150--7500 A. The extended wavelength coverage eliminates a systematic error in the determination of E(B-V), which originally resulted from the absense of data longward of 4800 A
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- 2000
35. The Distance to the Large Magellanic Cloud from the Eclipsing Binary HV2274
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Guinan, E. F., Fitzpatrick, E. L., DeWarf, L. E., Maloney, F. P., Maurone, P. A., Ribas, I., Gimenez, A., Pritchard, J. D., and Bradstreet, D. H.
- Subjects
Astrophysics - Abstract
The distance to the Large Magellanic Cloud (LMC) is crucial for the calibration of the Cosmic Distance Scale. We derive a distance to the LMC based on an analysis of ground-based photometry and HST-based spectroscopy and spectrophotometry of the LMC eclipsing binary system HV2274. Analysis of the optical light curve and HST/GHRS radial velocity curve provides the masses and radii of the binary components. Analysis of the HST/FOS UV/optical spectrophotometry provides the temperatures of the component stars and the interstellar extinction of the system. When combined, these data yield a distance to the binary system. After correcting for the location of HV2274 with respect to the center of the LMC, we find d(LMC) = 45.7 +/- 1.6 kpc or DM(LMC) = 18.30 +/- 0.07 mag. This result, which is immune to the metallicity-induced zero point uncertainties that have plagued other techniques, lends strong support to the ``short'' LMC distance scale as derived from a number of independent methods., Comment: 6 pages, including 2 pages of figures. Newly available optical (B and V) photometry has revealed -- and allowed the elimination of -- a systematic error in the previously reported determination of E(B-V) for HV2274. The new result is E(B-V) = 0.12 mag (as compared to the value of 0.083 reported in the original submission) and produces a DECREASE in the distance modulus of HV2274 by 0.12 mag. ApJ Letters, in press
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- 1998
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36. The 9 Aurigae System
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Krisciunas, K., Aspin, C., Geballe, T. R., Akazawa, H., Claver, C. F., Guinan, E. F., Landis, H. J., Luedeke, K. D., Ohkura, N., Ohshima, O., and Skillman, D. R.
- Subjects
Astrophysics - Abstract
The F0 V star 9 Aur A exhibits an irregular variability of amplitude $\approx $0.1 magnitude at optical wavelengths. The variations are too slow for it to be a $\delta$ Scuti-type star. There is no evidence for a close, interacting companion or ring of dust, either from infrared, ultraviolet, or speckle data. The photometric variability of 9 Aur A is similar to two other early F dwarf stars: $\gamma$ Doradus and HD 96008. 9 Aur B appears to be an M dwarf, 9 Aur C is an early- to mid-K dwarf star, and 9 Aur E, if it is a member of the system, probably is a normal white dwarf. 9 Aur D is most likely an unrelated and distant K giant. [See note added in press regarding a fourth member of this class of ``variables without a cause", and short term variations of the radial velocity of 9 Aur.], Comment: 16 pages plus 2 tables plus 6 figures Edinburgh Astronomy Preprint 6/93
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- 1993
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37. Patient experiences of a physiotherapy-led multidisciplinary rehabilitative intervention after successful treatment for oesophago-gastric cancer
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Bennett, A. E., O’Neill, L., Connolly, D., Guinan, E. M., Boland, L., Doyle, S. L., O’Sullivan, J., Reynolds, J. V., and Hussey, J.
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- 2018
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38. The views of patients with metastatic prostate cancer towards physical activity: a qualitative exploration
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Sheill, G., Guinan, E., Neill, L. O, Hevey, D., and Hussey, J.
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- 2018
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39. Physical activity and advanced cancer: the views of oncology and palliative care physicians in Ireland
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Sheill, G., Guinan, E., Neill, L. O., Hevey, D., and Hussey, J.
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- 2018
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40. Measuring the impact of oesophagectomy on physical functioning and physical activity participation: a prospective study
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Guinan, E. M., Bennett, A. E., Doyle, S. L., O’Neill, L., Gannon, J., Foley, G., Elliott, J. A., O’Sullivan, J., Reynolds, J. V., and Hussey, J.
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- 2019
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41. Patient Experiences of a Telehealth Multidisciplinary Cancer Rehabilitation Programme: Qualitative Findings from the ReStOre@Home Feasibility Study
- Author
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O’Brien, A., Brennan, L., O’Neill, L., Connolly, D., Guinan, E., Reynolds, J. V., and Hussey, J.
- Abstract
Purpose. Multidisciplinary rehabilitation programmes providing exercise, nutrition support, education, and peer support can effectively meet the rehabilitation needs of upper gastrointestinal (UGI) cancer survivors. This study aimed to explore the experiences of participants who engaged in a telehealth, multidisciplinary rehabilitation programme for UGI cancer survivors. Methods. This single-arm feasibility study recruited participants who completed curative treatment for UGI cancer. Participants (n = 10, male = 9) aged 58–76 years were 5–17 months postsurgery. A 12-week telehealth rehabilitation programme was delivered via video call, consisting of group resistance training, remotely monitored aerobic training, 1 : 1 dietary counselling, 1 : 1 physiotherapy support, and group education sessions. Independent researchers conducted semistructured interviews at postintervention assessments. Transcripts were analysed using reflexive thematic analysis (RTA). Results. RTA of participant transcripts generated three overarching themes: (1) ReStOre@Home impacted psychosocial and physical needs by addressing a broad and meaningful gap in services, (2) paving a pathway towards prosperity, and (3) contrasting experiences with using technology. Participants’ preferences and recommendations for future telehealth programmes were discussed. Conclusions. A telehealth multidisciplinary rehabilitation programme supported participants in physical and psychosocial recovery. Qualitative analysis identified an important ongoing need for some in-person care and provided detailed insights into participant experiences during telehealth-delivered rehabilitation.
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- 2023
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42. Pre-existing invasive fungal infection is not a contraindication for allogeneic HSCT for patients with hematologic malignancies: a CIBMTR study
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Maziarz, R T, Brazauskas, R, Chen, M, McLeod, A A, Martino, R, Wingard, J R, Aljurf, M, Battiwalla, M, Dvorak, C C, Geroge, B, Guinan, E C, Hale, G A, Lazarus, H M, Lee, J-W, Liesveld, J L, Ramanathan, M, Reddy, V, Savani, B N, Smith, F O, Strasfeld, L, Taplitz, R A, Ustun, C, Boeckh, M J, Gea-Banacloche, J, Lindemans, C A, Auletta, J J, and Riches, M L
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- 2017
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43. Patient Experiences of a Telehealth Multidisciplinary Cancer Rehabilitation Programme: Qualitative Findings from the ReStOre@Home Feasibility Study.
- Author
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O'Brien, A., Brennan, L., O'Neill, L., Connolly, D., Guinan, E., Reynolds, J. V., and Hussey, J.
- Subjects
CANCER patient psychology ,PILOT projects ,AFFINITY groups ,RESEARCH methodology ,HOSPITAL health promotion programs ,INTERVIEWING ,QUALITATIVE research ,HEALTH care teams ,DESCRIPTIVE statistics ,THEMATIC analysis ,CANCER patient rehabilitation ,TELEMEDICINE - Abstract
Purpose. Multidisciplinary rehabilitation programmes providing exercise, nutrition support, education, and peer support can effectively meet the rehabilitation needs of upper gastrointestinal (UGI) cancer survivors. This study aimed to explore the experiences of participants who engaged in a telehealth, multidisciplinary rehabilitation programme for UGI cancer survivors. Methods. This single-arm feasibility study recruited participants who completed curative treatment for UGI cancer. Participants (n = 10, male = 9) aged 58–76 years were 5–17 months postsurgery. A 12-week telehealth rehabilitation programme was delivered via video call, consisting of group resistance training, remotely monitored aerobic training, 1 : 1 dietary counselling, 1 : 1 physiotherapy support, and group education sessions. Independent researchers conducted semistructured interviews at postintervention assessments. Transcripts were analysed using reflexive thematic analysis (RTA). Results. RTA of participant transcripts generated three overarching themes: (1) ReStOre@Home impacted psychosocial and physical needs by addressing a broad and meaningful gap in services, (2) paving a pathway towards prosperity, and (3) contrasting experiences with using technology. Participants' preferences and recommendations for future telehealth programmes were discussed. Conclusions. A telehealth multidisciplinary rehabilitation programme supported participants in physical and psychosocial recovery. Qualitative analysis identified an important ongoing need for some in-person care and provided detailed insights into participant experiences during telehealth-delivered rehabilitation. [ABSTRACT FROM AUTHOR]
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- 2023
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44. Close Binary Stars (Étoiles Doubles Serrées)
- Author
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Rodonò, M., Guinan, E. F., Kondo, Y., Clausen, J. V., Drechsel, H., Eggleton, P. P., Geldzahler, B. J., Hill, G., Kenyon, S. J., Szkody, P., Taam, R. E., Tutukov, A. V., Vilhu, O., Wheeler, J. C., Yamasaki, A., Zhai, Di-S., and Appenzeller, Immo, editor
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- 1997
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45. Role of cardiopulmonary exercise testing as a risk-assessment method in patients undergoing intra-abdominal surgery: a systematic review
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Moran, J., Wilson, F., Guinan, E., McCormick, P., Hussey, J., and Moriarty, J.
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- 2016
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46. Magnetic Activity in Close Binaries : Its Manifestations and Consequences
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Guinan, E. F., Giménez, A., Sahade, J., editor, McCluskey, G. E., Jr., editor, and Kondo, Y., editor
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- 1993
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47. Feasibility and efficacy of a supervised exercise intervention in de-conditioned cancer survivors during the early survivorship phase: the PEACH trial
- Author
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Broderick, J. M., Guinan, E., Kennedy, M. J., Hollywood, D., Courneya, K. S., Culos-Reed, S. N., Bennett, K., O’ Donnell, D. M., and Hussey, J.
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- 2013
- Full Text
- View/download PDF
48. Core Outcome Set for Surgical Trials in Gastric Cancer (GASTROS Study):International patient and healthcare professional consensus
- Author
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Alkhaffaf, B, Metryka, A, Blazeby, J M, Glenny, A-M, Adeyeye, A, Costa, P M, Diez Del Val, I, Gisbertz, S S, Guner, A, Law, S, Lee, H-J, Li, Z, Nakada, K, Reim, D, Vorwald, P, Baiocchi, G L, Allum, W, Chaudry, M A, Griffiths, E A, Williamson, P R, Bruce, I A, Li, S., He, Yl, Xu, Z., Xue, Y., Liang, H., Li, G., Zhao, E., Neumann, P., O’Neill, L., Guinan, E., Zanotti, D., de Manzoni, G., Hagens, Erc., van Berge Henegouwen, Mi., Lages, P., Onofre, S., Restrepo Nunez, Rm., Salcedo Cabanas, G., Posada Gonzalez, M., Marin Campos, C., Candas, B., Emre Baki, B., Selim Bodur, M., Yildirim, R., Burak Cekic, A., Brown, J., Hayes, K., Daher, I., Gianchandani Moorjani, Rh., Adetoyese Adeyeye, A., Sulaiman Olayide, A., Mitsuo Leon-Takahashi, A., Pueyo Rabanal, A., Peri, A., Boddy, A., Novotny, A., Charalabopoulos, A., Alemdar, A., Souadka, A., Rodrigues Gomes, Am., Lazaro, A., Maciel Da Silva, A., do Rosario da Conceicao Silva e Santos, A., Guidi, A., Silva Bernardes, Aj., Quinn, A., Isik, A., A Slipek, A., Candas Altinbas, B., Johnson Alegbeleye, B., Wool Eom, B., Frittoli, B., Lonsdale, B., Rogers, B., Ammori, Bj., Rau, B., Molteni, B., Byrne, Be., Villacıs- Bermeo, Ba., Villacıs Gallardo, Be., Kose, B., Sampedro Nogueira, Cj., Loureiro, C., Oliveira de Sousa, Cm., Collins, Cg., Nonso Ekwunife, C., Chukwunwendu Osuagwu, C., Wong, Cly., Winkler, C., Reim, D., Kjær, Dw., Cooper, D., Horner, D., Irvine, D., Bowrey, Dj., Chuter, Dj., Elliot, D., Mcghee, D., Toth, D., Ofner, D., Manatakis, Dk., Silveira Martins, Dr., Belt, Ejt., Cattaneo, E., Samadov, E., Colak, E., Treppiedi, E., Guglielmi, E., Redondo- Villahoz, E., Ciferri, E., Tiemens-de Graaf, E., Cocozza, E., Pape, E., Drozdov, Es., Enrico, F., Rashid, F., Sandri, Marco, Rosa, F., Mingol Navarro, F., Simionato Perrotta, F., Chan, Fsy., Saavedra Tomasich, Fd., Takeda, Fr., Farrell, F., Olanike Wuraola, F., Rosero, G., Bevilacqua, G., Baronio, G., Mura, G., D’Eugenio, G., Ortega-Perez, G., Tilt, G., Sutcliffe, G., Mureddu, G., Guerra Jacob, G., Daneri, H., Olufemi Gbenga, H., Okabe, H., Kingsford Smith, I., Olawale Lateef, I., Garosio, I., Hatipoglu, I., Gockel, I., Negoi, I., Min, Ish., Mesquita, Imm., Diez del Val, I., Leemhuis, Jhf., Gossage, Ja., Weindelmayer, J., Izbicki, Jr., McKenzie Manson, J., Kelly, J., Stoot, Jhmb., Haveman, Jw., Brown, Jd., Sultan, J., Hassall, J., van Sandick, J., Saunders, Jh., Clarke, Jk., Heisterkamp, J., Vargas, Ji., Couselo Villanueva, Jm., Ingmire, J., Mcewen, J., Galindo Alvarez, J., Turner, J., Peng, J., Roberts, K., Brandon, Kg., Mitchell, K., Mccarthy, K., Akhtar, K., Mikhailovich, Kn., Corbelli, L., Medeiros Milhomem, L., Solaini, L., Fengyuan, L., Xinchun, L., Timmermans, L., Porritt, L., Taglietti, L., Bonavina, L., F. Pinheiro L., de los Angeles Mayo Ossorio, M., Schiavo, M., Marchesiello, M., das Dores Vieira Leite, M., Demois, M., Di Felice, Mt., de Sousa, Md., Takahashi, M., Forshaw, M., Berselli, M., Paro, M., Usta, Ma., Yan, Mh., Pinchin, M., Caprioli, M., Rubbini, M., Cowen, M., Herrera Servin, Ma., Li, Mz., Sasako, M., Shukri Jahit, M., Ngonyoku Muhinga, M., Tareen, Ma., Ahmad, Mf., Bodur, Ms., Kaban, M., Farooq, N., Coburn, N., Cooper, N., Blencowe, Ns., Loria, N., de Vries, N., Adami Andreollo, N., Koksal, N., Zanini, N., Kreuser, N., Okkabaz, N., Damiana, O., Afuwape, O., Kayode Fasiku, O., Comensoli, O., F. Koroye O., Capener, P., Morgagni, P., Pernadas Lages, Pm., Wilkerson, Pm., Turner, P., Dutton, P., Hayes, P., Vorwald, P., Singh, P., Gan, Q., Kottayasamy Seenivasagam, R., Ayloor Seshadri, R., Guevara Castro, R., Douglas, R., Koshy, Rm., Yıldırım, R., Skipworth, Rje., Gould, Ra., Wetherill, Rc., Shaw, R., Burley, Ra., Palatucci, R., Racalbuto, R., Correia Casaca, Rm., Lagarde, Sm., Gana, S., Marietti, S., Qureshi, S., Morales-Conde, S., Molfino, S., Barreto, Sg., Turkyilmaz, S., Turan-Trabzon, S., Frisch, S., Castoldi, S., Belloni, S., Flisi, S., Galloway, S., Maria, Sr., Royston, S., Boyle, T., Sezer, T., Mengardo, V., Concepcion Martın, V., Lee Wills, V., Owen-Holt, V., Casagrande, V., Al-Khyatt, W., Jansen, W., Wang, W., Eshuis, W., Polkowski, Wp., Huang, X., Wang, X., Chen, Xz., Gonzalez Dominguez, Y., Wang, Y., Viswanath, Yks., He, Yl., Demir, Z., Na, Z., Surgery, CCA - Cancer Treatment and Quality of Life, CCA - Cancer biology and immunology, AGEM - Amsterdam Gastroenterology Endocrinology Metabolism, CCA - Imaging and biomarkers, Experimental Immunology, Clinical Immunology and Rheumatology, CCA -Cancer Center Amsterdam, and CCA - Cancer Treatment and quality of life
- Subjects
medicine.medical_specialty ,Manchester Cancer Research Centre ,business.industry ,gastric cancer ,ResearchInstitutes_Networks_Beacons/mcrc ,Delphi method ,MEDLINE ,Cancer ,medicine.disease ,Outcome (game theory) ,03 medical and health sciences ,0302 clinical medicine ,Quality of life (healthcare) ,030220 oncology & carcinogenesis ,Family medicine ,gastros ,Medicine ,Surgery ,030212 general & internal medicine ,Stage (cooking) ,Adverse effect ,business ,Set (psychology) - Abstract
Background Surgery is the primary treatment that can offer potential cure for gastric cancer, but is associated with significant risks. Identifying optimal surgical approaches should be based on comparing outcomes from well designed trials. Currently, trials report different outcomes, making synthesis of evidence difficult. To address this, the aim of this study was to develop a core outcome set (COS)—a standardized group of outcomes important to key international stakeholders—that should be reported by future trials in this field. Methods Stage 1 of the study involved identifying potentially important outcomes from previous trials and a series of patient interviews. Stage 2 involved patients and healthcare professionals prioritizing outcomes using a multilanguage international Delphi survey that informed an international consensus meeting at which the COS was finalized. Results Some 498 outcomes were identified from previously reported trials and patient interviews, and rationalized into 56 items presented in the Delphi survey. A total of 952 patients, surgeons, and nurses enrolled in round 1 of the survey, and 662 (70 per cent) completed round 2. Following the consensus meeting, eight outcomes were included in the COS: disease-free survival, disease-specific survival, surgery-related death, recurrence, completeness of tumour removal, overall quality of life, nutritional effects, and ‘serious’ adverse events. Conclusion A COS for surgical trials in gastric cancer has been developed with international patients and healthcare professionals. This is a minimum set of outcomes that is recommended to be used in all future trials in this field to improve trial design and synthesis of evidence.
- Published
- 2021
49. The Mysterious Great Dimming of Betelgeuse
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Dupree, Andrea, Calderwood, T., Guinan, E., and Montarges, M.
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Astrophysics::High Energy Astrophysical Phenomena ,Post Main Sequence Cool Stars ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
The bright, cool supergiant Betelgeuse became historically faint in February 2020. Various explanations have been offered for its unusual behavior - including conjectures this foreshadows an imminent supernova event. Direct imaging, spatially resolved spectroscopy, polarization measures, infrared, optical and ultraviolet spectra and more help us to unravel what happened to the star. The current state of the star as well as new results from spectroscopic observations with HST will be reported in advance of the next optical minimum expected in the spring of 2021.
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- 2021
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50. The effect of aerobic exercise on metabolic and inflammatory markers in breast cancer survivors—a pilot study
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Guinan, E., Hussey, J., Broderick, J. M., Lithander, F. E., O’Donnell, D., Kennedy, M. J., and Connolly, E. M.
- Published
- 2013
- Full Text
- View/download PDF
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