Technology requirements for future Earth-to-geosynchronous orbit transportation systems. Volume 2: Technical results

Technologies either critical to performance of offering cost advantages compared to the investment required to bring them to usable confidence levels are identified. A total transportation system is used as an evaluation yardstick. Vehicles included in the system are a single stage to orbit launch vehicle used in a priority cargo role, a matching orbit transfer vehicle, a heavy lift launch vehicle with a low Earth orbit delivery capability of 226, 575 kg, and a matching solar electric cargo orbit transfer vehicle. The system and its reference technology level are consistent with an initial operational capability in 1990. The 15 year mission scenario is based on early space industrialization leading to the deployment of large systems such as power satellites. Life cycle cost benefits in discounted and undiscounted dollars for each vehicle, technology advancement, and the integrated transportation system are calculated. A preliminary functional analysis was made of the operational support requirements for ground based and space based chemical propulsion orbit transfer vehicles

Technology requirements for future Earth-to-geosynchronous orbit transportation systems. Volume 3: Appendices

Technological requirements and forecasts of rocket engine parameters and launch vehicles for future Earth to geosynchronous orbit transportation systems are presented. The parametric performance, weight, and envelope data for the LOX/CH4, fuel cooled, staged combustion cycle and the hydrogen cooled, expander bleed cycle engine concepts are discussed. The costing methodology and ground rules used to develop the engine study are summarized. The weight estimating methodology for winged launched vehicles is described and summary data, used to evaluate and compare weight data for dedicated and integrated O2/H2 subsystems for the SSTO, HLLV and POTV are presented. Detail weights, comparisons, and weight scaling equations are provided

Technology requirements for future Earth-to-geosynchronous orbit transportation systems. Volume 1: Executive summary

Technologies including accelerated technology that are critical to performance and/or provide cost advantages for future space transportation systems are identified. Mission models are scoped and include priority missions, and cargo missions. Summary data, providing primary design concepts and features, are given for the SSTO, HLLV, POTV, and LCOTV vehicles. Significant system costs and total system costs in terms of life cycle costs in both discounted and undiscounted dollars are summarized for each of the vehicles

The Critique of Scholastic Language in Renaissance Humanism and Early Modern Philosophy

This article studies some key moments in the long tradition of the critiqueof scholastic language, voiced by humanists and early-modern philosophers alike. It aims at showing how the humanist idiom of “linguistic usage,” “convention,” “custom,” “common” and “natural” language, and “everyday speech” was repeated and put to new use by early-modern philosophers in their own critique of scholastic language. Focusing on Valla, Vives, Sanches, Gassendi, Hobbes, and Leibniz, the article shows that all these thinkers shared a conviction that scholastic language, at least in its more baroque forms, was artificial, unnatural, uninformative, ungrammatical, and quasi-precise. The scholastics were accused of having introduced a terminology that was a far cry from the common language people spoke, wrote, and read. But what was meant by “common language” and such notions? They were not so easy to define. For the humanists, it meant the Latin of the great classical authors, but this position, as the article suggests, had its tensions. In the later period it became even more difficult to give positive substance to these notions, as the world became, linguistically speaking, increasingly more pluralistic. Yet the attack on scholasticlanguage continued to be conducted in these terms. The article concludes that the long road of what we may call the democratization of philosophical language, so dear to early-modern philosophers, had its roots – ironically perhaps – in the humanist return to classical Latin as the common language

YAP\u2013TEAD1 control of cytoskeleton dynamics and intracellular tension guides human pluripotent stem cell mesoderm specification

The tight regulation of cytoskeleton dynamics is required for a number of cellular processes, including migration, division and differentiation. YAP\u2013TEAD respond to cell\u2013cell interaction and to substrate mechanics and, among their downstream effects, prompt focal adhesion (FA) gene transcription, thus contributing to FA-cytoskeleton stability. This activity is key to the definition of adult cell mechanical properties and function. Its regulation and role in pluripotent stem cells are poorly understood. Human PSCs display a sustained basal YAP-driven transcriptional activity despite they grow in very dense colonies, indicating these cells are insensitive to contact inhibition. PSC inability to perceive cell\u2013cell interactions can be restored by tampering with Tankyrase enzyme, thus favouring AMOT inhibition of YAP function. YAP\u2013TEAD complex is promptly inactivated when germ layers are specified, and this event is needed to adjust PSC mechanical properties in response to physiological substrate stiffness. By providing evidence that YAP\u2013TEAD1 complex targets key genes encoding for proteins involved in cytoskeleton dynamics, we suggest that substrate mechanics can direct PSC specification by influencing cytoskeleton arrangement and intracellular tension. We propose an aberrant activation of YAP\u2013TEAD1 axis alters PSC potency by inhibiting cytoskeleton dynamics, thus paralyzing the changes in shape requested for the acquisition of the given phenotype