We present a dynamical model of the high mass X-ray binary LMC X-1 based on high-resolution optical spectroscopy and extensive optical and nearinfrared photometry. From our new optical data we find an orbital period of P = 3.90917±0.00005 days. We present a refined analysis of the All Sky Monitor data from RXTE and find an X-ray period of P = 3.9094 ± 0.0008 days, which is consistent with the optical period. A simple model of Thomson scattering in the stellar wind can account for the modulation seen in the X-ray light curves. The V − K color of the star (1.17 ± 0.05) implies A V = 2.28 ± 0.06, which is much larger than previously assumed. For the secondary star, we measure a radius of R 2 = 17.0±0.8 R ⊙ and a projected rotational velocity of V rot sin i = 129.9±2.2 km s −1 . Using these measured properties to constrain the dynamical model, we find an inclination of i = 36.38±1.92 • , a secondary star mass of M 2 = 31.79±3.48 M ⊙ , and a black hole mass of 10.91 ± 1.41 M ⊙ . The present location of the secondary star in a temperature-luminosity diagram is consistent with that of a star with an initial mass of 35 M ⊙ that is 5 Myr past the zero-age main sequence. The star nearly fills its Roche lobe (≈ 90% or more), and owing to the rapid change in radius with time in its present evolutionary state, it will encounter its Roche lobe and begin rapid and possibly unstable mass transfer on a timescale of a few hundred thousand years.

The government acquisition system is consistently plagued by cost growth and by attempts at acquisition reform. Despite these persistent challenges, the academic community lacks a methodology for studying complex acquisition programs both in‐depth and longitudinally throughout their life cycles. In this paper, we present a framework for studying complex acquisition programs that provides researchers with a strategy for systematically studying cost growth mechanisms. The proposed framework provides a means to identify specific technical and organizational mechanisms for cost growth, to organize those mechanisms using design structure matrices, and to observe the evolution of those mechanisms throughout a program's life cycle. To illustrate the utility of our framework, we apply it to analyze a case study of the National Polar‐orbiting Operational Environmental Satellite System (NPOESS) program. Ultimately, we demonstrate that the framework enables us to generate unique insights into the mechanisms that induced cost growth on NPOESS and that were unacknowledged by previous studies. Specifically, we observed that complexity was injected into the technical system well before the program's cost estimates began to increase and that it was the complexity of the NPOESS organization that hindered the program's ability to effectively estimate and to manage its costs.

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The term jointness refers to activities or operations that are executed collaboratively by more than one government agency or military department. While joint operations have become increasingly common and successful, the government continues to struggle with joint system acquisition: in fact, although a common motivation for joint acquisition is cost savings, recent studies suggest that joint programs experience larger cost growth than non-joint programs and that it may be more cost effective for agencies to acquire systems independently rather than jointly. This thesis explains why joint programs often experience large cost growth and how jointness itself may induce it.To understand the cost of jointness, this thesis proposes and demonstrates a new approach for studying large, complex acquisition programs whereby the evolution of a program's organizational and technical architectures is quantified and observed using a design structure matrix (DSM)-based tool. Using this approach, one is able to gain an in-depth understanding of the underlying mechanisms that drive a program's costs, as well as global perspective on cost growth throughout a program's lifecycle. The utility of this approach is demonstrated by applying it to study the cost impacts of jointness on three programs that developed environmental monitoring systems for low Earth orbit.

The demand for renewable and sustainable energy has generated considerable interest in the conversion of cellulosic biomass into liquid fuels such as ethanol using a filamentous fungus. While attempts have been made to study cellulose metabolism through the use of knock-out mutants, there have been no systematic effort to characterize natural variation for cellulose metabolism in ecotypes adapted to different habitats. Here, we characterized natural variation in saccharification of cellulose and fermentation in 73 ecotypes and 89 laboratory strains of the model fungus Neurospora crassa. We observed significant variation in both traits among natural and laboratory generated populations, with some elite strains performing better than the reference strain. In the F1 population N345, 15% of the population outperformed both parents with the top performing strain having 10% improvement in ethanol production. These results suggest that natural alleles can be exploited through fungal breeding for developing elite industrial strains for bioethanol production.

Bruce Cameron-is a lecturer in engineering systems at MIT and a consultant on platform strategies. At MIT, Bruce ran the MIT Commonality Study, a 16-firm investigation of platforming returns. His current clients include Fortune 500 firms in high tech, aerospace, transportation, and consumer goods. He holds an undergraduate degree from the University of Toronto and graduate degrees from MIT. [bcameron@mit.edu] Markus Bradford-is a junior economics major at MIT. He currently works as an undergraduate researcher at the MIT System Architecture Lab. His industry experience ranges from government and financial services and he is interested in project management in the technical space.[ mbrdfrd@mit.edu]Edward Crawley-is a professor of aeronautics & aeronautics and engineering systems at MIT. His research interests include system architecture, design, and decision authority in complex technical systems that involve economic and stakeholder issues. [crawley@mit.edu] AbstractAlthough joint programs are typically formed to reduce costs, recent studies have suggested that they may actually be more costly than non-joint programs. In this paper, we explore this hypothesis using an in-depth case study of the NPOESS program. To study jointness, we apply a semi-quantitative framework that quantifies the complexity impacts of jointness and enables us to observe their evolution over time. In particular, we describe how jointness impacted the NPOESS program-by inducing technical and organizational complexity-and illustrate how the relationship between both complexity types enabled, sustained, and induced cost growth. We also explain the evolution of the program's technical and organizational complexity by identifying five key technical decisions and collaborating agency interactions that increased complexity and cost. Finally, we conclude by noting that a key source of the NPOESS program's cost growth was not jointness per say, but rather, was the result of a mismatch in the amount of jointness that was present in the program's technical system but was absent in its managing organization.

Traditionally, government space agencies have developed aggregated systems that cohost multiple capabilities on shared spacecraft buses. However, in response to cost growth and schedule delays on past programs, leaders in the government space community have expressed an interest in disaggregation, or distributing their capabilities across multiple spacecraft. Since their aggregated National Polar-orbiting Operational Satellite System (NPOESS) program was cancelled in 2010, both the National Oceanic and Atmospheric Administration (NOAA) and the Department of Defense (DoD) have investigated opportunities to reduce program costs through disaggregation. This paper expands their initial investigation and explores the cost impacts of aggregation and disaggregation across a large trade space of candidate architectures for environmental monitoring in low-Earth orbit. We find that on average, aggregated architectures are less costly than fully disaggregated ones but also find opportunities for cost savings by developing semiaggregated systems, or systems with one or two satellites per orbital plane. Finally, we investigate several trades that are currently under consideration by NOAA and the DoD and make recommendations for future environmental monitoring systems in low-Earth orbit.N 1994, President Bill Clinton directed the Department of Defense (DoD) and the National Oceanic and Atmospheric Administration (NOAA) to combine their existing environmental satellite systems and to collaboratively develop the joint National Polar-orbiting Operational Environmental Satellite System (NPOESS). By executing the agencies' missions jointly, the NPOESS program enabled NOAA and the DoD to share the development, production, operations, and launch costs of the new system and to save the government $1.3 billion .

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