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Yamakawa, Y., Peng, M. W., & Deeds, D. L. (2015). Rising From the Ashes: Cognitive Determinants of Venture Growth After Entrepreneurial Failure. Entrepreneurship Theory and Practice, 39(2), 209–236.
Abstract: How does previous entrepreneurial failure influence future entrepreneurship? More specifically, under what conditions do entrepreneurs who rebound from failure do better in the next round? Drawing on the cognitive literature in attribution and motivation, we focus on entrepreneurs' reaction to failure and the growth of their subsequent ventures. Leveraging a survey database of new-venture founders with failure experiences, we investigate how their internal attribution of the cause of failure, their intrinsic motivation to start up another business after failure, and the extent of their failure experiences impact the growth of their subsequent ventures.
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Sargent, B. A., Srinivasan, S., Speck, A., Volk, K., Kemper, C., Reach, W. T., et al. (2015). Spitzer-IRS Spectroscopic Studies of Oxygen-Rich Asymptotic Giant Branch Star and Red Supergiant Star Dust Properties. (216.pp. 03–216.03). American Astronomical Society Meeting Abstracts, 225.
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Sloan, G. C., Groenewegen, M., Srinivasan, S., Lagadec, E., Kraemer, K. E., McDonald, I., et al. (2015). Dust and metallicity in carbon stars. (216.pp. 04–216.04). American Astronomical Society Meeting Abstracts, 225.
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Naslim, N., Kemper, F., Madden, S. C., Hony, S., Chu, Y. - H., Galliano, F., et al. (2015). Molecular hydrogen emission in the interstellar medium of the Large Magellanic Cloud. Mon.~Not.~R.~Astron.~Soc., 446(3), 2490–2504.
Abstract: We present the detection and analysis of molecular hydrogen emission towards ten interstellar regions in the Large Magellanic Cloud. We examined low-resolution infrared spectral maps of 12 regions obtained with the Spitzer infrared spectrograph (IRS). The pure rotational 0-0 transitions of H2 at 28.2 and 17.1 μm are detected in the IRS spectra for 10 regions. The higher level transitions are mostly upper limit measurements except for three regions, where a 3σ detection threshold is achieved for lines at 12.2 and 8.6 μm. The excitation diagrams of the detected H2 transitions are used to determine the warm H2 gas column density and temperature. The single-temperature fits through the lower transition lines give temperatures in the range 86-137 K. The bulk of the excited H2 gas is found at these temperatures and contributes ˜5-17 per cent to the total gas mass. We find a tight correlation of the H2 surface brightness with polycyclic aromatic hydrocarbon and total infrared emission, which is a clear indication of photoelectric heating in photodissociation regions. We find the excitation of H2 by this process is equally efficient in both atomic- and molecular-dominated regions. We also present the correlation of the warm H2 physical conditions with dust properties. The warm H2 mass fraction and excitation temperature show positive correlations with the average starlight intensity, again supporting H2 excitation in photodissociation regions.
Keywords: ISM: molecules; photodissociation region (PDR); galaxies: ISM; Magellanic Cloud; infrared: ISM
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Ruffle, P. M. E., Kemper, F., Jones, O. C., Sloan, G. C., Kraemer, K. E., Woods, P. M., et al. (2015). Spitzer infrared Spectrograph point source classification in the Small Magellanic Cloud. Mon.~Not.~R.~Astron.~Soc., .
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Zhao-Geisler, R., Köhler, R., Kemper, F., Kerschbaum, F., Mayer, A., Quirrenbach, A., et al. (2015). Spectro-imaging of the asymmetric inner molecular and dust shell region of the Mira variable W Hya with MIDI/VLTI. Pub.~Astron.~Soc.~Pacific, .
Abstract: We have observed W Hya, one of the closest and best studied oxygen-rich evolved star, in the dust
Keywords: my_papers
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Jones, O. C., McDonald, I., Rich, R. M., Kemper, F., Boyer, M. L., Zijlstra, A. A., et al. (2015). A Spitzer Space Telescope survey of extreme asymptotic giant branch stars in M32. Mon.~Not.~R.~Astron.~Soc., 446(2), 1584–1596.
Abstract: We investigate the population of cool, evolved stars in the Local Group dwarf elliptical galaxy M32, using Infrared Array Camera observations from the Spitzer Space Telescope. We construct deep mid-infrared colour-magnitude diagrams for the resolved stellar populations within 3.5 arcmin of M32's centre, and identify those stars that exhibit infrared excess. Our data are dominated by a population of luminous, dust-producing stars on the asymptotic giant branch (AGB) and extend to approximately 3 mag below the AGB tip. We detect for the first time a sizeable population of `extreme' AGB stars, highly enshrouded by circumstellar dust and likely completely obscured at optical wavelengths. The total dust-injection rate from the extreme AGB candidates is measured to be 7.5 × 10-7 M⊙ yr-1, corresponding to a gas mass-loss rate of 1.5 × 10-4 M⊙ yr-1. These extreme stars may be indicative of an extended star formation epoch between 0.2 and 5 Gyr ago.
Keywords: stars: AGB and post-AGB; stars: late-type; stars: mass-loss; galaxies: individual: M32; galaxies: stellar content; infrared: stars
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Naslim, N., Kemper, F., Madden, S. C., Hony, S., Chu, Y. - H., Galliano, F., et al. (2015). Molecular hydrogen emission in the interstellar medium of the Large Magellanic Cloud. Mon.~Not.~R.~Astron.~Soc., 446(3), 2490–2504.
Abstract: We present the detection and analysis of molecular hydrogen emission towards ten interstellar regions in the Large Magellanic Cloud. We examined low-resolution infrared spectral maps of 12 regions obtained with the Spitzer infrared spectrograph (IRS). The pure rotational 0-0 transitions of H2 at 28.2 and 17.1 μm are detected in the IRS spectra for 10 regions. The higher level transitions are mostly upper limit measurements except for three regions, where a 3σ detection threshold is achieved for lines at 12.2 and 8.6 μm. The excitation diagrams of the detected H2 transitions are used to determine the warm H2 gas column density and temperature. The single-temperature fits through the lower transition lines give temperatures in the range 86-137 K. The bulk of the excited H2 gas is found at these temperatures and contributes ˜5-17 per cent to the total gas mass. We find a tight correlation of the H2 surface brightness with polycyclic aromatic hydrocarbon and total infrared emission, which is a clear indication of photoelectric heating in photodissociation regions. We find the excitation of H2 by this process is equally efficient in both atomic- and molecular-dominated regions. We also present the correlation of the warm H2 physical conditions with dust properties. The warm H2 mass fraction and excitation temperature show positive correlations with the average starlight intensity, again supporting H2 excitation in photodissociation regions.
Keywords: ISM: molecules; photodissociation region (PDR); galaxies: ISM; Magellanic Cloud; infrared: ISM
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Ruffle, P. M. E., Kemper, F., Jones, O. C., Sloan, G. C., Kraemer, K. E., Woods, P. M., et al. (2015). Spitzer infrared Spectrograph point source classification in the Small Magellanic Cloud. Mon.~Not.~R.~Astron.~Soc., .
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Sargent, B. A., Srinivasan, S., Speck, A., Volk, K., Kemper, C., Reach, W. T., et al. (2015). Spitzer-IRS Spectroscopic Studies of Oxygen-Rich Asymptotic Giant Branch Star and Red Supergiant Star Dust Properties. (216.pp. 03–216.03). American Astronomical Society Meeting Abstracts, 225.
Abstract: We analyze the dust emission features seen in Spitzer Space Telescope Infrared Spectrograph (IRS) spectra of Oxygen-rich (O-rich) asymptotic giant branch (AGB) and red supergiant (RSG) stars. The spectra come from the Spitzer Legacy program SAGE-Spectroscopy (PI: F. Kemper) and other archival Spitzer-IRS programs. The broad 10 and 20 micron emission features attributed to amorphous dust of silicate composition seen in the spectra show evidence for systematic differences in the centroid of both emission features between O-rich AGB and RSG populations. Radiative transfer modeling using the GRAMS grid of models of AGB and RSG stars suggests that the centroid differences are due to differences in dust properties. We present an update of our investigation of differences in dust composition, size, shape, etc that might be responsible for these spectral differences. We explore how these differences may arise from the different circumstellar environments around RSG and O-rich AGB stars. BAS acknowledges funding from NASA ADAP grant NNX13AD54G.
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