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81 results on '"Balasubramanian, Bala"'

1. The Habitable Exoplanet Observatory (HabEx) Mission Concept Study Final Report

Author

Gaudi, B. Scott, Seager, Sara, Mennesson, Bertrand, Kiessling, Alina, Warfield, Keith, Cahoy, Kerri, Clarke, John T., Domagal-Goldman, Shawn, Feinberg, Lee, Guyon, Olivier, Kasdin, Jeremy, Mawet, Dimitri, Plavchan, Peter, Robinson, Tyler, Rogers, Leslie, Scowen, Paul, Somerville, Rachel, Stapelfeldt, Karl, Stark, Christopher, Stern, Daniel, Turnbull, Margaret, Amini, Rashied, Kuan, Gary, Martin, Stefan, Morgan, Rhonda, Redding, David, Stahl, H. Philip, Webb, Ryan, Alvarez-Salazar, Oscar, Arnold, William L., Arya, Manan, Balasubramanian, Bala, Baysinger, Mike, Bell, Ray, Below, Chris, Benson, Jonathan, Blais, Lindsey, Booth, Jeff, Bourgeois, Robert, Bradford, Case, Brewer, Alden, Brooks, Thomas, Cady, Eric, Caldwell, Mary, Calvet, Rob, Carr, Steven, Chan, Derek, Cormarkovic, Velibor, Coste, Keith, Cox, Charlie, Danner, Rolf, Davis, Jacqueline, Dewell, Larry, Dorsett, Lisa, Dunn, Daniel, East, Matthew, Effinger, Michael, Eng, Ron, Freebury, Greg, Garcia, Jay, Gaskin, Jonathan, Greene, Suzan, Hennessy, John, Hilgemann, Evan, Hood, Brad, Holota, Wolfgang, Howe, Scott, Huang, Pei, Hull, Tony, Hunt, Ron, Hurd, Kevin, Johnson, Sandra, Kissil, Andrew, Knight, Brent, Kolenz, Daniel, Kraus, Oliver, Krist, John, Li, Mary, Lisman, Doug, Mandic, Milan, Mann, John, Marchen, Luis, Marrese-Reading, Colleen, McCready, Jonathan, McGown, Jim, Missun, Jessica, Miyaguchi, Andrew, Moore, Bradley, Nemati, Bijan, Nikzad, Shouleh, Nissen, Joel, Novicki, Megan, Perrine, Todd, Pineda, Claudia, Polanco, Otto, Putnam, Dustin, Qureshi, Atif, Richards, Michael, Riggs, A. J. Eldorado, Rodgers, Michael, Rud, Mike, Saini, Navtej, Scalisi, Dan, Scharf, Dan, Schulz, Kevin, Serabyn, Gene, Sigrist, Norbert, Sikkia, Glory, Singleton, Andrew, Shaklan, Stuart, Smith, Scott, Southerd, Bart, Stahl, Mark, Steeves, John, Sturges, Brian, Sullivan, Chris, Tang, Hao, Taras, Neil, Tesch, Jonathan, Therrell, Melissa, Tseng, Howard, Valente, Marty, Van Buren, David, Villalvazo, Juan, Warwick, Steve, Webb, David, Westerhoff, Thomas, Wofford, Rush, Wu, Gordon, Woo, Jahning, Wood, Milana, Ziemer, John, Arney, Giada, Anderson, Jay, Maíz-Apellániz, Jesús, Bartlett, James, Belikov, Ruslan, Bendek, Eduardo, Cenko, Brad, Douglas, Ewan, Dulz, Shannon, Evans, Chris, Faramaz, Virginie, Feng, Y. Katherina, Ferguson, Harry, Follette, Kate, Ford, Saavik, García, Miriam, Geha, Marla, Gelino, Dawn, Götberg, Ylva, Hildebrandt, Sergi, Hu, Renyu, Jahnke, Knud, Kennedy, Grant, Kreidberg, Laura, Isella, Andrea, Lopez, Eric, Marchis, Franck, Macri, Lucas, Marley, Mark, Matzko, William, Mazoyer, Johan, McCandliss, Stephan, Meshkat, Tiffany, Mordasini, Christoph, Morris, Patrick, Nielsen, Eric, Newman, Patrick, Petigura, Erik, Postman, Marc, Reines, Amy, Roberge, Aki, Roederer, Ian, Ruane, Garreth, Schwieterman, Edouard, Sirbu, Dan, Spalding, Christopher, Teplitz, Harry, Tumlinson, Jason, Turner, Neal, Werk, Jessica, Wofford, Aida, Wyatt, Mark, Young, Amber, and Zellem, Rob

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The Habitable Exoplanet Observatory, or HabEx, has been designed to be the Great Observatory of the 2030s. For the first time in human history, technologies have matured sufficiently to enable an affordable space-based telescope mission capable of discovering and characterizing Earthlike planets orbiting nearby bright sunlike stars in order to search for signs of habitability and biosignatures. Such a mission can also be equipped with instrumentation that will enable broad and exciting general astrophysics and planetary science not possible from current or planned facilities. HabEx is a space telescope with unique imaging and multi-object spectroscopic capabilities at wavelengths ranging from ultraviolet (UV) to near-IR. These capabilities allow for a broad suite of compelling science that cuts across the entire NASA astrophysics portfolio. HabEx has three primary science goals: (1) Seek out nearby worlds and explore their habitability; (2) Map out nearby planetary systems and understand the diversity of the worlds they contain; (3) Enable new explorations of astrophysical systems from our own solar system to external galaxies by extending our reach in the UV through near-IR. This Great Observatory science will be selected through a competed GO program, and will account for about 50% of the HabEx primary mission. The preferred HabEx architecture is a 4m, monolithic, off-axis telescope that is diffraction-limited at 0.4 microns and is in an L2 orbit. HabEx employs two starlight suppression systems: a coronagraph and a starshade, each with their own dedicated instrument., Comment: Full report: 498 pages. Executive Summary: 14 pages. More information about HabEx can be found here: https://www.jpl.nasa.gov/habex/

Published
2020

2. Key Technologies for the Wide Field Infrared Survey Telescope Coronagraph Instrument

Author

Bailey, Vanessa P., Armus, Lee, Balasubramanian, Bala, Baudoz, Pierre, Bellini, Andrea, Benford, Dominic, Berriman, Bruce, Bhattacharya, Aparna, Boccaletti, Anthony, Cady, Eric, Novati, Sebastiano Calchi, Carpenter, Kenneth, Ciardi, David, Crill, Brendan, Danchi, William, Debes, John, Demers, Richard, Dohlen, Kjetil, Effinger, Robert, Ferrari, Marc, Frerking, Margaret, Gelino, Dawn, Girard, Julien, Grady, Kevin, Groff, Tyler, Harding, Leon, Helou, George, Henning, Avenhaus, Janson, Markus, Kalirai, Jason, Kane, Stephen, Kasdin, N. Jeremy, Kenworthy, Matthew, Kern, Brian, Krist, John, Kruk, Jeffrey, Lagrange, Anne Marie, Laine, Seppo, Langlois, Maud, Coroller, Herve Le, Lindensmith, Chris, Lowrance, Patrick, Maire, Anne-Lise, Malhotra, Sangeeta, Mandell, Avi, McElwain, Michael, Prada, Camilo Mejia, Mennesson, Bertrand, Meshkat, Tiffany, Moody, Dwight, Morrissey, Patrick, Moustakas, Leonidas, N'Diaye, Mamadou, Nemati, Bijan, Noecker, Charley, Paladini, Roberta, Perrin, Marshall, Poberezhskiy, Ilya, Postman, Marc, Pueyo, Laurent, Ramirez, Solange, Ranc, Clement, Rhodes, Jason, Riggs, A. J. E., Rizzo, Maxime, Roberge, Aki, Rouan, Daniel, Schlieder, Joshua, Seo, Byoung-Joon, Shaklan, Stuart, Shi, Fang, Soummer, Remi, Spergel, David, Stapelfeldt, Karl, Stark, Christopher, Tamura, Motohide, Tang, Hong, Trauger, John, Turnbull, Margaret, van der Marel, Roeland, Vigan, Arthur, Williams, Benjamin, Wollack, Edward J., Ygouf, Marie, Zhao, Feng, Zhoud, Hanying, and Zimmerman, Neil

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) is a high-contrast imager and integral field spectrograph that will enable the study of exoplanets and circumstellar disks at visible wavelengths. Ground-based high-contrast instrumentation has fundamentally limited performance at small working angles, even under optimistic assumptions for 30m-class telescopes. There is a strong scientific driver for better performance, particularly at visible wavelengths. Future flagship mission concepts aim to image Earth analogues with visible light flux ratios of more than 10^10. CGI is a critical intermediate step toward that goal, with a predicted 10^8-9 flux ratio capability in the visible. CGI achieves this through improvements over current ground and space systems in several areas: (i) Hardware: space-qualified (TRL9) deformable mirrors, detectors, and coronagraphs, (ii) Algorithms: wavefront sensing and control; post-processing of integral field spectrograph, polarimetric, and extended object data, and (iii) Validation of telescope and instrument models at high accuracy and precision. This white paper, submitted to the 2018 NAS Exoplanet Science Strategy call, describes the status of key CGI technologies and presents ways in which performance is likely to evolve as the CGI design matures., Comment: Submitted in response to the 2018 NAS Exoplanet Science Strategy call. 5 pages, 2 figures

Published
2019

3. The Habitable Exoplanet Observatory (HabEx) Mission Concept Study Interim Report

Author

Gaudi, B. Scott, Seager, Sara, Mennesson, Bertrand, Kiessling, Alina, Warfield, Keith, Kuan, Gary, Cahoy, Kerri, Clarke, John T., Domagal-Goldman, Shawn, Feinberg, Lee, Guyon, Olivier, Kasdin, Jeremy, Mawet, Dimitri, Robinson, Tyler, Rogers, Leslie, Scowen, Paul, Somerville, Rachel, Stapelfeldt, Karl, Stark, Christopher, Stern, Daniel, Turnbull, Margaret, Martin, Stefan, Alvarez-Salazar, Oscar, Amini, Rashied, Arnold, William, Balasubramanian, Bala, Baysinger, Mike, Blais, Lindsey, Brooks, Thomas, Calvet, Rob, Cormarkovic, Velibor, Cox, Charlie, Danner, Rolf, Davis, Jacqueline, Dorsett, Lisa, Effinger, Michael, Eng, Ron, Garcia, Jay, Gaskin, Jonathan, Harris, Joby, Howe, Scott, Knight, Brent, Krist, John, Levine, David, Li, Mary, Lisman, Doug, Mandic, Milan, Marchen, Luis, Marrese-Reading, Colleen, McGowen, Jim, Miyaguchi, Andrew, Morgan, Rhonda, Nemati, Bijan, Nikzad, Shouleh, Nissen, Joel, Novicki, Megan, Perrine, Todd, Redding, David, Richards, Michael, Rud, Mike, Scharf, Dan, Serabyn, Gene, Shaklan, Stuart, Smith, Scott, Stahl, Mark, Stahl, Phil, Tang, Hao, Van Buren, David, Villalvazo, Juan, Warwick, Steve, Webb, David, Wofford, Rush, Woo, Jahning, Wood, Milana, Ziemer, John, Douglas, Ewan, Faramaz, Virginie, Hildebrandt, Sergi, Meshkat, Tiffany, Plavchan, Peter, Ruane, Garreth, and Turner, Neal

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

For the first time in human history, technologies have matured sufficiently to enable a mission capable of discovering and characterizing habitable planets like Earth orbiting sunlike stars other than the Sun. At the same time, such a platform would enable unique science not possible from ground-based facilities. This science is broad and exciting, ranging from new investigations of our own solar system to a full range of astrophysics disciplines. The Habitable Exoplanet Observatory, or HabEx, is one of four studies currently being undertaken by NASA in preparation for the 2020 Astrophysics Decadal Survey. HabEx has been designed to be the Great Observatory of the 2030s, with community involvement through a competed and funded Guest Observer (GO) program. This interim report describes the HabEx baseline concept, which is a space-based 4-meter diameter telescope mission concept with ultraviolet (UV), optical, and near-infrared (near-IR) imaging and spectroscopy capabilities. More information on HabEx can be found at https://www.jpl.nasa.gov/habex, Comment: 212 Pages

Published
2018

5. The Administration of Levodopa in a Patient With Parkinson’s Disease Using a Novel Maxillofacial Route: A First-in-Human Report

Author

Thirunavukarasu, Suresh, primary, Ramanan, Balasubramanian Bala Venkata, additional, Suresh, Sathya Krishnan, additional, Antonisamy, Vincent Jayakumar, additional, Varadharaj, Devi, additional, Shanmugam, Paranjothi, additional, Verma, Kavita, additional, Elumalai, Canmany, additional, Selvakumar, Gladson, additional, Elumalai, Ahila, additional, Prabahar, Lydia, additional, Janardhanan, Hridwik Adiyeri, additional, and UR, Anoop, additional

Published
2023
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8. Enabling High-Contrast Imaging of Binary Stars With the Roman Space Telescope Coronagraph Instrument

Author

Prada, Camilo Mejia, Balasubramanian, Bala, Pluzhnik, Eugene, Ruane, Garreth, Riggs, A.J. Eldorado, Sirbu, Dan, Belilok, Ruslan, and Bendek, Eduardo

Abstract

A large fraction of Sun-like stars is contained in binary systems, in fact within 10 pc there are 67 FGK stars, out of which 42 belong to a multi-star system, and 28 have companion leak that is greater than 1e-9 contrast, assuming typical Hubble-quality space optics. Currently, those binary stars are not included in the Roman Space Telescope Coronagraph Instrument target list, but they could be observed if high-contrast imaging around binary star systems using Roman was possible. The Multi-Star Wavefront Control (MSWC) algorithm can be used to suppress companion star leakage. If the targets have angular separations larger than the Nyquist controllable region of the Deformable Mirror, MSWC must operate in its Super-Nyquist (SN) mode. This mode requires a target star replica within the SN region in order to provide the ability to null speckles at SN angular separations. For the case of Roman, more than half of the targets that can be observed using MSWC, including Alpha Centauri, have angular separations larger than the Nyquist controllable region of the 48x48 actuator Deformable Mirror (DM) to be used. In this paper, we describe how super-Nyquist MSWC can be implemented in Roman CGI adding a mild grating on a replica of the Wide-field Shaped Pupil mask, which would use a spare space in the Shaped Pupil Active Mechanism. We present the feasibility analysis, simulation results, and discuss the latest results on MSWC experiment from three different laboratories at NASA Ames, the Jet Propulsion Laboratory, and the Subaru telescope.

Published
2021

9. ADMINISTRATION OF LEVODOPA IN A PARKINSON’S PATIENT USING A NOVEL ORAL AND MAXILLOFACIAL ROUTE – A FIRST IN HUMAN STUDY

Author

Thirunavukarasu, Suresh, primary, Ramanan, Balasubramanian Bala Venkata, additional, Suresh, Sathya Krishnan, additional, Antonisamy, Vincent Jayakumar, additional, Varadharaj, Devi, additional, Shanmugam, Paranjothi, additional, Verma, Kavita, additional, Elumalai, Canmany, additional, Selvakumar, Gladson, additional, Elumalai, Ahila, additional, Prabahar, Lydia, additional, Janardhanan, Hridwik Adiyeri, additional, and UR, Anoop, additional

Published
2023
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14. ZERODUR Substrates for Application of High-Temperature Protected-Aluminum Far Ultraviolet Coatings

Author

Quijada, Manuel A, Sheikh, David, Richardson, J. Gabriel, Del Hoyo, Javier G, and Balasubramanian, Bala K

Subjects
Optics
Abstract

Recent development in coating deposition processes for aluminum mirrors that are protected with a metal-fluoride overcoat (such as LiF, MgF2, or LiF) have improved reflectance performance particularly in the far-ultraviolet (FUV) part of the optical spectrum. The active research in this area is motivated by the fact that these gains in reflectance are expected to significantly increase the throughput of any future FUV-sensitive NASA missions into the Lyman Ultraviolet. These reflectance improvements are attributed, in part, by performing the metal-fluoride overcoat depositions with the substrates at an elevated temperature as high as 220-250 degrees Celsius. ZERODUR® is a widely used material as a mirror substrate because, among other things, it exhibits a low coefficient of thermal expansion (CTE) over a wide range of temperatures. Moreover, ZERODUR® has recently been proposed for several future NASA concept missions where this improved FUV mirror coating may be used. Given the elevated temperature at which these improved FUV coatings are produced, it is imperative to make sure that heating of the substrate will not significantly impact the final figure of the coated mirror. In this paper, we will study and report the effects of heating ZERODUR® up to the highest temperature mentioned above (250 degrees Celsius) during a simulated coating process. These studies are relevant since it has been reported the CTE will change slightly if ZERODUR® is cooled down from application temperatures between 130 degrees Celsius and 320 degrees Celsius with rates that differ from the initial production annealing rate of 3 degrees Celsius per hour.

Published
2019

17. EFFECTIVENESS OF HOME BASED CARE INTERVENTION ON KNOWLEDGE AND SKILLS REGARDINGCARE OF LOW BIRTH WEIGHT BABIES AMONG MOTHERS IN SELECTED AREA, SRIKAKULAM, A.P

Author

Ms. Parupalli Swarna kumar, Dr. Venu Lata saxena, and Dr. N. Balasubramanian bala

Subjects
General Earth and Planetary Sciences, General Environmental Science
Abstract

Quantitative research approach and true experimental research design of pre and post test was used for the present study. Purposive sampling technique wasused to recruit the samples and assigned as experimental and control group. The researcher developed a home based care intervention on care of Low birth weight babies among mothers to evaluate its effectiveness. The data was collected through the structured closed ended questionnaire i.e. knowledge questionnaire on home care of low birth weight

Published
2021

18. WFIRST coronagraph pictures for STMD

Author

Demers, Rick, Poberezhskiy, Ilya, Cady, Eric, Krist, John, Balasubramanian, Bala K, Riggs, A.J. Eldorado, Zhao, Feng, Effinger, Bobby, and Siegler, Nick

Abstract

UNKNOWN

Published
2017

19. WFIRST coronagraph pictures for STMD

Author

Siegler, Nick, Effinger, Bobby, Zhao, Feng, Riggs, A.J. Eldorado, Balasubramanian, Bala K, Krist, John, Cady, Eric, Poberezhskiy, Ilya, and Demers, Rick

Published
2017

21. UV Coatings, Polarization, and Coronagraphy

Author

Bolcar, Matthew R, Quijada, Manuel, West, Garrett, Balasubramanian, Bala, Krist, John, Martin, Stefan, and Sabatke, Derek

Subjects
Optics, Astronomy
Abstract

Presenation for the Large UltraViolet Optical Infrared (LUVOIR) and Habitable Exoplanet Imager (HabEx) Science and Technology Definition Teams (STDT) on technical considerations regarding ultraviolet coatings, polarization, and coronagraphy. The presentations review the state-of-the-art in ultraviolet coatings, how those coatings generate polarization aberrations, and recent study results from both the LUVOIR and HabEx teams.

Published
2016

24. Polarization Study Update

Author

Traub, Wes, Tang, Hong, Mcguire, Jim, Balasubramanian, Bala, Rud, Mike, and Krist, John

Subjects
Physics (General)
Published
2016

25. Key Technologies for the Wide Field Infrared Survey Telescope Coronagraph Instrument

Author

Bailey, Vanessa P., Armus, Lee, Balasubramanian, Bala, Baudoz, Pierre, Bellini, Andrea, Benford, Dominic, Berriman, Bruce, Bhattacharya, Aparna, Boccaletti, Anthony, Cady, Eric, Novati, Sebastiano Calchi, Carpenter, Kenneth, Ciardi, David, Crill, Brendan, Danchi, William, Debes, John, Demers, Richard, Dohlen, Kjetil, Effinger, Robert, Ferrari, Marc, Frerking, Margaret, Gelino, Dawn, Girard, Julien, Grady, Kevin, Groff, Tyler, Harding, Leon, Helou, George, Henning, Avenhaus, Janson, Markus, Kalirai, Jason, Kane, Stephen, Kasdin, N. Jeremy, Kenworthy, Matthew, Kern, Brian, Krist, John, Kruk, Jeffrey, Lagrange, Anne Marie, Laine, Seppo, Langlois, Maud, Coroller, Herve Le, Lindensmith, Chris, Lowrance, Patrick, Maire, Anne-Lise, Malhotra, Sangeeta, Mandell, Avi, McElwain, Michael, Prada, Camilo Mejia, Mennesson, Bertrand, Meshkat, Tiffany, Moody, Dwight, Morrissey, Patrick, Moustakas, Leonidas, N'Diaye, Mamadou, Nemati, Bijan, Noecker, Charley, Paladini, Roberta, Perrin, Marshall, Poberezhskiy, Ilya, Postman, Marc, Pueyo, Laurent, Ramirez, Solange, Ranc, Clement, Rhodes, Jason, Riggs, A. J. E., Rizzo, Maxime, Roberge, Aki, Rouan, Daniel, Schlieder, Joshua, Seo, Byoung-Joon, Shaklan, Stuart, Shi, Fang, Soummer, Remi, Spergel, David, Stapelfeldt, Karl, Stark, Christopher, Tamura, Motohide, Tang, Hong, Trauger, John, Turnbull, Margaret, van der Marel, Roeland, Vigan, Arthur, Williams, Benjamin, Wollack, Edward J., Ygouf, Marie, Zhao, Feng, Zhoud, Hanying, Zimmerman, Neil, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], [SDU]Sciences of the Universe [physics], Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) is a high-contrast imager and integral field spectrograph that will enable the study of exoplanets and circumstellar disks at visible wavelengths. Ground-based high-contrast instrumentation has fundamentally limited performance at small working angles, even under optimistic assumptions for 30m-class telescopes. There is a strong scientific driver for better performance, particularly at visible wavelengths. Future flagship mission concepts aim to image Earth analogues with visible light flux ratios of more than 10^10. CGI is a critical intermediate step toward that goal, with a predicted 10^8-9 flux ratio capability in the visible. CGI achieves this through improvements over current ground and space systems in several areas: (i) Hardware: space-qualified (TRL9) deformable mirrors, detectors, and coronagraphs, (ii) Algorithms: wavefront sensing and control; post-processing of integral field spectrograph, polarimetric, and extended object data, and (iii) Validation of telescope and instrument models at high accuracy and precision. This white paper, submitted to the 2018 NAS Exoplanet Science Strategy call, describes the status of key CGI technologies and presents ways in which performance is likely to evolve as the CGI design matures., Submitted in response to the 2018 NAS Exoplanet Science Strategy call. 5 pages, 2 figures

Published
2020

26. Optical verification experiments of sub-scale starshades

Author

Harness, Anthony, primary, Shaklan, Stuart, additional, Willems, Phillip, additional, Kasdin, N. Jeremy, additional, Balasubramanian, Bala K., additional, Dumont, Philip, additional, White, Victor, additional, Yee, Karl, additional, Muller, Rich, additional, and Galvin, Michael, additional

Published
2021
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28. ANUBIS - A Probe-Class UVO Space Observatory

Author

Scowen, Paul, Morse, Jon, Ardila, David, Balasubramanian, Bala, Bally, John, Devereux, Nick, Dyster, John, Figer, Don, Finkelstein, Steven, France, Kevin, Gavilan, Lisseth, Gorjian, Varoujan, Green, James, Grillmair, Carl, Hartigan, Patrick, Hendrix, Amanda, Howk, Chris, Hu, Renyu, Hutchings, John, Jansen, Rolf Kafka, Stella, Kasting, Jim, Larruquert, Juan Ignacio, Matthews, Gary, McCandliss, Stephan, McGrath, Melissa, Nikzad, Shouleh, Raymond, John, Sahai, Raghvendra, Siegmund, Ossy, Shkolnik, Evgenya, Stahl, Phil, Tripp, Todd, Turner, Neal, Willacy, Karen, Williams, Ben, Windhorst, Rogier, and Yanatsis, Dave

Abstract

14 pags., 1 fig., 1 tab., We propose a next generation Probe-class UV-optical (UVO) observatory called ANUBIS that is capable of conducting wide-field imaging and far-ultraviolet (FUV) spectroscopic surveys to address critical topics in modern astrophysics and planetary science.

Published
2019

29. TPF-C performance modeling

Author

Shaklan, Stuart, Marchen, Luis, Green,Joe, Lay, Oliver, John Krist, Balasubramanian, Bala, Give’on, Amir, Levine, Marie, Kissel, Andy, and Kwack, Eug

Published
2008

30. Technology maturity update for the Habitable-zone Exoplanet Imaging Observatory (HabEx) concept (Conference Presentation)

Author

Barto, Allison A., Breckinridge, James B., Stahl, H. Philip, Morgan, Rhonda M., Warfield, Keith, Stahl, H. P., Kuan, Gary, Mennesson, Bertrand, Nikzad, Shouleh, Azizi, Alireza, Balasubramanian, Bala, Mawet, Dimitri, Redding, David C., Serabyn, Eugene, Shaklan, Stuart, Hennessy, John J., Warwick, Steve, Barto, Allison A., Breckinridge, James B., Stahl, H. Philip, Morgan, Rhonda M., Warfield, Keith, Stahl, H. P., Kuan, Gary, Mennesson, Bertrand, Nikzad, Shouleh, Azizi, Alireza, Balasubramanian, Bala, Mawet, Dimitri, Redding, David C., Serabyn, Eugene, Shaklan, Stuart, Hennessy, John J., and Warwick, Steve

Abstract

Since the 2010 Decadal Survey, the technologies needed for direct imaging of exoplanets advanced significantly. NASA investment in these technologies, prioritized in the 2010 Decadal Survey, have ripened to a maturity to enable direct imaging of earthlike exoplanets. For the first time since the discovery of exoplanets, a direct imaging mission can be conceived to start in less than ten years, possibly as soon as five years. The HabEx Observatory Concept design utilizes technologies that are state of the art or near to state of the art with clear paths of development. The philosophy of the design favors as high a Technology Readiness Level (TRL) as possible to minimize risk. We discuss the HabEx technology challenges and assess the TRL expected by the submission of the Final Report in 2019. Many of the enabling technologies are at, or expected to be at, TRL 5 by 2019, and the remaining technologies are at TRL 4. We update the technology maturity roadmap with technology advances in the past year and expand it to include an Architecture option which is a 3.2 m diameter on-axis segmented aperture with a starshade only. The starshade suppresses starlight before it enters the telescope, allowing the telescope optical performance and stability to be significantly looser than for a coronagraph, thus enabling a segmented primary mirror design that can meet stability requirements with minimal advancement from the state of the art. We assess the exoplanet-driven technologies of HabEx, including starshades, coronagraphs, deformable mirrors, wavefront control, 4 m aperture mirrors, jitter mitigation, segmented mirror stability, and low-noise detectors.

Published
2019

31. HEBS and Binary 1-sinc masks simulations, HCIT experiments and results

Author

Balasubramanian, Bala K, Hoppe, Dan, Wilson, Dan, Echternach, Pierre, Trauger, John, Halverson, Peter, Niessner, Al, Shi, Fang, and Lowman, Andrew

Abstract

Based on preliminary experiments and results with a binary 1-sinc mask in the HCIT early in August 2004, we planned for a detailed experiment to compare the performance of HEBS and Binary masks under nearly identical conditions in the HCIT. This report details the design and fabrication of the masks, simulated predictions, and experimental results.

Published
2005

32. Technology maturity update for the Habitable-zone Exoplanet Imaging Observatory (HabEx) concept

Author

Morgan, Rhonda M., primary, Warfield, Keith, additional, Stahl, H. Philip, additional, Mennesson, Bertrand, additional, Kuan, Gary, additional, Balasubramanian, Bala, additional, Mawet, Dimitri, additional, Nikzad, Shouleh, additional, Hennessy, John J., additional, Azizi, Alireza, additional, Shaklan, Stuart, additional, and Serabyn, Eugene, additional

Published
2019
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33. Technology maturity for the habitable-zone exoplanet imaging observatory (HabEx) concept

Author

Lystrup, Mackenzie, MacEwen, Howard A., Fazio, Giovanni G., Batalha, Natalie, Siegler, Nicholas, Tong, Edward C., Morgan, Rhonda, Warfield, Keith, Kuan, Gary, Stahl, H. Phi, Mennesson, Bertrand, Balasubramanian, Bala, Mawet, Dimitri, Nikzad, Shouleh, Nissen, Joel, Shaklan, Stuart, Serabyn, Eugene, Stapelfeldt, Karl, Warwick, Steve, Lystrup, Mackenzie, MacEwen, Howard A., Fazio, Giovanni G., Batalha, Natalie, Siegler, Nicholas, Tong, Edward C., Morgan, Rhonda, Warfield, Keith, Kuan, Gary, Stahl, H. Phi, Mennesson, Bertrand, Balasubramanian, Bala, Mawet, Dimitri, Nikzad, Shouleh, Nissen, Joel, Shaklan, Stuart, Serabyn, Eugene, Stapelfeldt, Karl, and Warwick, Steve

Abstract

HabEx Architecture A is a 4m unobscured telescope mission concept optimized for direct imaging and spectroscopy of potentially habitable exoplanets, and also enables a wide range of general astrophysics science. The exoplanet detection and characterization drives the enabling core technologies. A hybrid starlight suppression approach of a starshade and coronagraph diversifies technology maturation risk. In this paper we assess these exoplanet-driven technologies, including elements of coronagraphs, starshades, mirrors, jitter mitigation, wavefront control, and detectors. By utilizing high technology readiness solutions where feasible, and identifying required technology development that can begin early, HabEx will be well positioned for assessment by the community in 2020 Astrophysics Decadal Survey.

Published
2018

38. Influence of Board Diversity and Characteristics on CEO Compensation: Contingent Effects of Concentrated Ownership

Author

Balasubramanian, Bala N., Barua, Samir K., and Karthik, D.

Subjects
ComputingMilieux_LEGALASPECTSOFCOMPUTING
Abstract

The crisis in the financial and the banking sectors in 2008-2009 brought back into focus the issue of CEO and top management compensation. The unconscionably high compensations, unjustified even remotely by performance, raised concerns about governance of companies. The study, the first of its kind, investigates the efficacy of board diversity and various measures of board independence for different ownership structures and different types of concentrated owners – private domestic, private foreign and government, in controlling CEO compensation in the same economic setting. The sample for the study consists of companies that were a part of the diversified 100 stock index of the National Stock Exchange in India for the period 2007-2012. The main theoretical contribution is that the impact of board diversity and board mechanisms is moderated by the type of concentrated ownership. Separation of board chair and CEO positions is the single most important governance measure for controlling excessive compensation to CEOs. Other board mechanisms to check executive compensation work along predicted lines for firms with dominant foreign owners but do not work for other types of concentrated ownership. Gender diversity and large number of non-executive independent directors deflate CEO compensation only in case of companies with foreign dominant owners. Besides theoretical contribution on moderating influence of type of concentrated ownership, the results provide actionable inputs for changes in legislation and practice of corporate governance.

Published
2015

39. Strengthening Corporate Governance in India A Review of Legislative and Regulatory Initiatives in 2013-14

Author

Balasubramanian, Bala N.

Abstract

The passing of the long awaited Companies Act in 2013 is probably the single most important development in India’s history of corporate legislation, next only to the monumental Companies Act 1956 which it replaces. While significant improvements have been effected in required standards of corporate governance, there is also some concern regarding overly increasing compliance and regulatory costs and efforts for companies as well as their independent directors. Among the major provisions of the Act are those of restraining voting rights of interested shareholders on related party transactions, recognition of board accountability to stakeholders besides shareholders, and extension of several good governance requirements to relatively large unlisted corporations. The author (Adjunct Professor at the Indian Institute of Management Ahmedabad, and Founding and former Chairman, and Advisor of the Centre for Corporate Governance and Citizenship at the Indian Institute of Management Bangalore) acknowledges with gratitude the very helpful comments and suggestions of Afra Afsharipour, Sharad Abhyankar and Nawshir Mirza.

Published
2014

41. Ownership Trends in Corporate India 2001-2011: Evidence and Implications

Author

Balasubramanian, Bala N. and Ramaswamy, Anand

Abstract

The first decade of the new millennium saw dramatic changes in the ownership patterns in major listed corporations in India. Two developments were striking: promoters especially in the domestic private sector bolstered up their holdings to assure continued entrenchment; and institutional investors significantly increased their holdings especially in the private sector management controlled companies segment. In both cases, these increases were achieved at the cost of retail non-institutional shareholders whose holdings correspondingly recorded a steep fall. This paper documents this evidence, seeks to identify their underlying rationale and assess their implications for corporate equity investment and governance in the country.

Published
2013

43. Board Interlocks and Their Impact on Corporate Governance: The Indian Experience - Coping with Corporate Cholesterol

Author

Balasubramanian, Bala N., Barua, Samir K., Bhagavatula, Suresh, and George, Rejie

Abstract

Board interlocks occur when a director of one organization sits on the board of directors of another organization. The causes and consequences of these interlocks have been much debated in the western literature but comparatively little is known about interlocks in Indian corporate boards. Board interlocks are essentially analogous to cholesterol. Both are facts of life. Like good cholesterol, there are aspects of interlocking directorates that are beneficial and there are others that are detrimental to the corporation and its stakeholders and their respective interests. In this study, we find that board interlocks are quite widespread in India. Taking a (numerically) small but nevertheless (in terms of market capitalization) an important slice of available corporate data, we observed that in 2010, ‘highly boarded’ directors (defined as those on the board of 5 or more listed NSE companies) who constitute just 6 percent of the overall pool of directors among NSE100 companies are associated with 486 NSE listed companies which account for a whopping 66 percent of the total market capitalization of all NSE listed companies. Interestingly, there appears to be a marked increase in market capitalization of these ‘highly boarded’ companies, which these ‘highly boarded’ directors are linked to over the last several years. For instance, for the 3 years from 2001 to 2003, the market capitalization of ‘highly boarded’ companies ranged between 33 percent to 43 percent; it moved up to peak of 70 percent in 2007 and was at 66 percent in 2010 (the latest year in the study period). The substantive rise in market capitalization of these ‘highly boarded’ companies has coincided with only a marginal increase (from 5% to 6%) in the proportion of ‘highly boarded’ directorships. These trends suggest that despite the well-intentioned regulatory reforms (a) the extent of over-boarding/interlocking among directors has not come down (there is actually a marginal increase) and (b) there appears to be increasing concentration of power among key individuals. Given the general view that concentration of power in a few individuals or entities is not desirable in the larger interests of society, it would appear that the observed trends in the concentration of power among a handful of the country’s corporate elite is a matter for substantive public policy concern. Finally, the regression analysis indicates a positive impact on Return on Assets (ROA) for ‘highly boarded’ directors signifying a negation of the agency centric conceptualization on the role of multiple directors. Instead, connectedness variables (Eigen vector) which proxy for the Resource dependency hypothesis are quite strongly supported. In a nutshell, from public policy perspective, the analysis potentially reflects the ‘bad cholesterol’ elements of multiple directorships in terms of a tiny segment of ‘highly boarded’ directors controlling a significant portion of the country’s economic prowess, whereas the positive influences on company performance provide some evidence of the ‘good cholesterol’.

Published
2011

45. Hybrid lyot coronagraph for WFIRST: high contrast testbed demonstration in flight-like low flux environment

Author

Lystrup, Makenzie, MacEwen, Howard A., Fazio, Giovanni G., Batalha, Natalie, Siegler, Nicholas, Tong, Edward C., Seo, Byoung-Joon, Shi, Fang, Balasubramanian, Bala, Cady, Eric, Gordon, Brian, Kern, Brian, Lam, Raymond, Marx, David, Moody, Dwight, Muller, Richard, Patterson, Keith, Poberezhskiy, Ilya, Mejia Prada, Camilo, Riggs, A.J. Eldorado, Trauger, John, and Wilson, Daniel

Published
2018
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