Self assembly properties of primitive organic compounds

A central event in the origin of life was the self-assembly of amphiphilic, lipid-like compounds into closed microenvironments. If a primitive macromolecular replicating system could be encapsulated within a vesicular membrane, the components of the system would share the same microenvironment, and the result would be a step toward true cellular function. The goal of our research has been to determine what amphiphilic molecules might plausibly have been available on the early Earth to participate in the formation of such boundary structures. To this end, we have investigated primitive organic mixtures present in carbonaceous meteorites such as the Murchison meteorite, which contains 1-2 percent of its mass in the form of organic carbon compounds. It is likely that such compounds contributed to the inventory of organic carbon on the prebiotic earth, and were available to participate in chemical evolution leading to the emergence of the first cellular life forms. We found that Murchison components extracted into non-polar solvent systems are surface active, a clear indication of amphiphilic character. One acidic fraction self-assembles into vesicular membranes that provide permeability barriers to polar solutes. Other evidence indicates that the membranes are bimolecular layers similar to those formed by contemporary membrane lipids. We conclude that bilayer membrane formation by primitive amphiphiles on the early Earth is feasible. However, only a minor fraction of acidic amphiphiles assembles into bilayers, and the resulting membranes require narrowly defined conditions of pH and ionic composition to be stable. It seems unlikely, therefore, that meteoritic infall was a direct source of membrane amphiphiles. Instead, the hydrocarbon components and their derivatives more probably would provide an organic stock available for chemical evolution. Our current research is directed at possible reactions which would generate substantial quantities of membranogenic amphiphiles. One possibility is photochemical oxidation of hydrocarbons

Design Pedagogy: The New Architectural Studio and Its Consequences

This article argues that the typical architectural studio is both outmoded and irresponsible. It is outmoded because it typically is organized around a nineteenth-century model of design virtuosity, and it is irresponsible because it ignores pressing and current spatial justice problems. It also takes to task the aura of the academic setting in which the formally motivated studio reigns supreme. In lieu of this model of architectural education, the article argues for an education that empowers graduates to tackle the major problems that society currently faces: housing, climate, income inequality/unemployment and health. To do this, it acknowledges but suggests overthrowing the many institutional hurdles keeping architectural education attached to the status quo

How Rare Are Extraterrestrial Civilizations and When Did They Emerge?

It is shown that, contrary to an existing claim, the near equality between the lifetime of the sun and the timescale of biological evolution on earth does not necessarily imply that extraterrestrial civilizations are exceedingly rare. Furthermore, on the basis of simple assumptions it is demonstrated that a near equality between these two timescales may be the most probable relation. A calculation of the cosmic history of carbon production which is based on the recently determined history of the star formation rate suggests that the most likely time for intelligent civilizations to emerge in the universe, was when the universe was already older then about 10 billion years (for an assumed current age of about 13 billion years).Comment: 11 pages (including 2 figures), accepted for publication in Astrophys. Journa

Alternate route to soliton solutions in hydrogen-bonded chains

In this paper we offer an alternate route for investigating soliton solutions in hydrogen-bonded chains. This is done by examining a class of systems of two coupled real scalar fields. We show that this route allows investigating several models for hydrogen-bonded chains in a unified manner. We also show how to investigate interesting issues, in particular the one concerning classical or linear stability of solitonic solutions.Comment: 12 pages. Late

A Conversation on Labour & Practice

Automated approaches to design, fabrication, and construction present disruptive and potentially transformative challenges to the conventional practice of architecture, as computational workflows recalibrate traditional roles and responsibilities in the production of buildings. How does computational design change how labor is defined and enacted in architectural and construction practice? What are the ethical implications and questions that arise in this context, particularly as we consider the implications of uncompensated or under-compensated labor of those doing computational work? This keynote event brings together three architects and thinkers to critically explore the intersections between computation, labor, and practice. Peggy Deamer is Professor Emerita of Yale University’s School of Architecture, principal in the firm of Deamer, Studio, and a founding member of the Architecture Lobby, a group advocating for the value of architectural design and labor. Billie Faircloth is a Partner at KieranTimberlake, where she leads a transdisciplinary group leveraging research, design, and problem-solving processes across fields including environmental management, chemical physics, materials science, and architecture. Mollie Claypool is an architecture theorist and activist at AUAR and UCL Bartlett. Her work broadly focuses on issues of social justice highlighted by increasing automation in architecture and design production, such as the future of work, housing, platforms, localised manufacturing, and circular economies