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Your search keyword '"Iglesias, P. Martin"' showing total 19 results
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19 results on '"Iglesias, P. Martin"'

1. System Design for the Event Horizon Imaging Experiment Using the PECMEO Concept

Author

Kudriashov, V., Martin-Neira, M., Barat, I., Iglesias, P. Martin, Daganzo-Eusebio, E., Alagha, N., and Valenta, V.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The concept for space interferometry from Polar or Equatorial Circular Medium Earth Orbits (the PECMEO concept) is a promising way to acquire the image of the "shadow" of the event horizon of Sagittarius A* with an angular resolution of circa 5 microarcseconds. The concept is intended to decrease the size of the main reflector of the instrument to about 3 m using a precise orbit reconstruction based on Global Navigation Satellite System (GNSS) navigation, inter-satellite range and range-rate measurements, and data from the Attitude and Orbit Determination System (AODS). The paper provides the current progress on the definition of the subsystems required for the concept on the basis of simulations, radio regulations, and available technology. The paper proposes the requirement for the localization of the phase centre of the main reflector. The paper provides information about the visibility of GNSS satellites and the needed accuracies of the AODS. The paper proposes the frequency plan for the instrument and its Inter-Satellite Links (ISLs). The concepts for measurement of range and range rate using ISLs (as well as for the data exchange at these ISLs) are presented. The block diagram of the interferometer is described and its sensitivity is estimated. The link budget for both ISLs is given as well as their critical components. The calculated measurement quality factors are given. The paper shows the expected performance of the sub-systems of the interferometer. The requirements for the localization of the main reflectors and the information about the availability of the GNSS satellites are based on the simulations results. (Two sentences have been deleted in order to satisfy the maximum symbol count established by arXiv rules.) The paper provides input information for the development of the orbit reconstruction filter and the whole PECMEO system., Comment: 17 pages, 5 figures

Published
2021
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2. An Event Horizon Imager (EHI) Mission Concept Utilizing Medium Earth Orbit Sub-mm Interferometry

Author

Kudriashov, V., Martin-Neira, M., Roelofs, F., Falcke, H., Brinkerink, C., Baryshev, A., Hogerheijde, M., Young, A., Pourshaghaghi, H., Klein-Wolt, M., Moscibrodzka, M., Davelaar, J., Barat, I., Duesmann, B., Valenta, V., Armengol, J. M. Perdigues, De Wilde, D., Iglesias, P. Martin, Alagha, N., and Van Der Vorst, M.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Submillimeter interferometry has the potential to image supermassive black holes on event horizon scales, providing tests of the theory of general relativity and increasing our understanding of black hole accretion processes. The Event Horizon Telescope (EHT) performs these observations from the ground, and its main imaging targets are Sagittarius A* in the Galactic Center and the black hole at the center of the M87 galaxy. However, the EHT is fundamentally limited in its performance by atmospheric effects and sparse terrestrial $(u,v)$-coverage (Fourier sampling of the image). The scientific interest in quantitative studies of the horizon size and shape of these black holes has motivated studies into using space interferometry which is free of these limitations. Angular resolution considerations and interstellar scattering effects push the desired observing frequency to bands above 500 GHz. This paper presents the requirements for meeting these science goals, describes the concept of interferometry from Polar or Equatorial Medium Earth Orbits (PECMEO) which we dub the Event Horizon Imager (EHI), and utilizes suitable space technology heritage. In this concept, two or three satellites orbit at slightly different orbital radii, resulting in a dense and uniform spiral-shaped $(u,v)$-coverage over time. The local oscillator signals are shared via an inter-satellite link, and the data streams are correlated on-board before final processing on the ground. Inter-satellite metrology and satellite positioning are extensively employed to facilitate the knowledge of the instrument position vector, and its time derivative. The European space heritage usable for both the front ends and the antenna technology of such an instrument is investigated. Current and future sensors for the required inter-satellite metrology are listed. Intended performance estimates and simulation results are given., Comment: 23 pages, 10 figures

Published
2021
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4. An Event Horizon Imager (EHI) Mission Concept Utilizing Medium Earth Orbit Sub-mm Interferometry*

Author

V KUDRIASHOV, M MARTIN-NEIRA, F ROELOFS, H FALCKE, C BRINKERINK, A BARYSHEV, M HOGERHEIJDE, A YOUNG, H POURSHAGHAGHI, M KLEIN-WOLT, M MOSCIBRODZKA, J DAVELAAR, I BARAT, B DUESMANN, V VALENTA, ARMENGOL J M PERDIGUES, D DE WILDE, IGLESIAS P MARTIN, N ALAGHA, and DER VORST M VAN

Subjects
Complementary and alternative medicine, Pharmaceutical Science, Pharmacology (medical)
Published
2021

9. Adverse outcomes following hand surgery in patients with rheumatoid arthritis

Author

Menchaca-Tapia, Victor M, Rodríguez, Elizabeth M, Contreras-Yáñez, Irazú, Iglesias-Morales, Martin, and Pascual-Ramos, Virginia

Abstract

Background Up to 70% of patients with long-standing rheumatoid arthritis (RA) may present with rheumatic hand disease and benefit from hand surgical procedures (HSPs).Objective Through retrospective review, the present study aimed to report HSPs in RA patients at a tertiary care centre to identify patient adverse outcomes (AOs) and their predictors.Methods From 1989 to 2013, 96 patients who underwent =1 HSP(s) were identified from two local registries; their clinical records were independently reviewed by two trained physicians (surgeon and clinical) who used a standardized format. AOs were defined by consensus; data abstracter agreement was found in 90% of cases. Descriptive statistics were used in addition to Kaplan-Meier curves to determine the time to each AO, while logistic regression models were used to determine predictors of AOs.Results At first HSP, 89.6% of patients were female, had a mean (± SD) age of 49.1±12 years, a disease duration of 12.2±7.2 years, 93.6% were positive for rheumatoid factor and 24% were receiving intensive treatment. A total of 130 HSPs were performed: the most frequent interventions were arthrodesis (25.4%), resection of the ulnar head (15.4%) and tenorrhaphy (14.6%). During follow-up, 33 AOs were reported in 27 (28.1%) patients, 87% of which occurred after the first HSP. The most frequent AO subsets were impaired wound healing (18.2%) and exposed pin (15.2%). Longer disease duration at first HSP (OR 3.07 [95% CI 1.04 to 9.08]; P=0.04) and intensive treatment (OR 1.08 [95% CI 1.002 to 1.156]; P=0.045) were predictors of AOs. The optimal disease duration cut-off to predict AOs was 20.1 years.Conclusion Early referral of long-standing RA patients for hand surgery, along with less aggressive treatment, favoured improved surgical outcomes.

Published
2016
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10. Main NMR Characteristics of Synthetic (25r)-5α-furostanes†

Author

Iglesias-Arteaga, Martin A., Martínez, Carlos Pérez, and Manchado, Francisco Coll

Abstract

The assignment of 13C signals of synthetic (25R)-5α -furostanes together with the main 1H characteristics of the furostane side chain are presented. The main effects on chemical shifts due to conversion of ring F into an open chain are briefly discussed.

Published
2001
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11. Synthesis of 2‐Substituted‐5‐halo‐2,3‐dihydro‐4(H)‐pyrimidin‐4‐ones and Their Derivatization Utilizing the Sonogashira Coupling Reaction in the Enantioselective Synthesis of α‐Substituted β‐Amino Acids.

Author

Diaz‐Sanchez, Blanca R., Iglesias‐Arteaga, Martin A., Melgar‐Fernandez, Roberto, and Juaristi, Eusebio

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Published
2007
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15. Synthesis of a New Bisnorcholanic Lactone.

Author

Mola Garate, Jose L., Suarez Garcia, Leticia, Perez Martinez, Carlos S., Iglesias‐Arteaga, Martin A., Coll Herrera, Deysma, and Coll Manchado, Francisco

Abstract

For Abstract see ChemInform Abstract in Full Text.

Published
2003
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16. ChemInform Abstract: Spirostanic Analogues of Teasterone. Synthesis, Characterization and Biological Activity of Laxogenin, (23S)‐Hydroxylaxogenin and 23‐Ketolaxogenin (23‐Oxolaxogenin).

Author

Iglesias‐Arteaga, Martin A., Perez Gil, Roxana, Perez Martinez, Carlos S., and Coll Manchado, Francisco

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Published
2001
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17. ChemInform Abstract: Synthetic Steroidal Sapogenins. Part 3. 23‐Ketohecogenin and 23‐Ketoisochiapagenin.

Author

Iglesias Arteaga, Martin A., Perez Gil, Roxana, Perez Martinez, Carlos S., and Coll Manchado, Francisco

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Published
2000
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18. ChemInform Abstract: Synthesis and Characterization of (25R)‐2α,3α‐Epoxy‐5α‐spirostan‐12,23‐dione.

Author

Iglesias Arteaga, Martin A., Perez Martinez, Carlos S., and Coll Manchado, Francisco

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Published
1999
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19. ChemInform Abstract: 13C and 1H NMR Spectra of Synthetic (25R)‐5α‐Spirostanes.

Author

Iglesias Arteaga, Martin A., Perez Martinez, Carlos S., Perez Gil, Roxana, and Coll Manchado, Franciso

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Published
1999
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