Pomona College is a private liberal arts college located in Claremont, California, United States. Pomona is an exclusively undergraduate four-year institution and enrolled approximately 1,600 students in fall 2012.The founding member of the Claremont Colleges, Pomona is a non-sectarian, coeducational school. Since 1925, the Claremont Colleges, which have grown to include five undergraduate and two graduate institutions, have provided Pomona's student body with the resources of a larger university while maintaining the benefits of a small college.Pomona is ranked fifth out of all liberal arts colleges by U.S. News & World Report and eighth out of all undergraduate colleges and universities in the USA by Forbes. It is the most endowed liberal arts college in the country on a per capita basis, the fourth most endowed school on a per capita basis, and the second most selective liberal arts college by acceptance rate. Wikipedia.
Mangold S.L.,California Institute of Technology |
Oleary D.J.,Pomona College |
Grubbs R.H.,California Institute of Technology
Journal of the American Chemical Society | Year: 2014
Olefin metathesis has emerged as a promising strategy for modulating the stability and activity of biologically relevant compounds; however, the ability to control olefin geometry in the product remains a challenge. Recent advances in the design of cyclometalated ruthenium catalysts has led to new strategies for achieving such control with high fidelity and Z selectivity, but the scope and limitations of these catalysts on substrates bearing multiple functionalities, including peptides, remained unexplored. Herein, we report an assessment of various factors that contribute to both productive and nonproductive Z-selective metathesis on peptides. The influence of sterics, side-chain identity, and preorganization through peptide secondary structure are explored by homodimerization, cross metathesis, and ring-closing metathesis. Our results indicate that the amino acid side chain and identity of the olefin profoundly influence the activity of cyclometalated ruthenium catalysts in Z-selective metathesis. The criteria set forth for achieving high conversion and Z selectivity are highlighted by cross metathesis and ring-closing metathesis on diverse peptide substrates. The principles outlined in this report are important not only for expanding the scope of Z-selective olefin metathesis to peptides but also for applying stereoselective olefin metathesis in general synthetic endeavors. © 2014 American Chemical Society.
Morgens D.W.,Pomona College
Journal of Molecular Evolution | Year: 2013
Translation, coded peptide synthesis, arguably exists at the heart of modern cellular life. By orchestrating an incredibly complex interaction between tRNAs, mRNAs, aaRSs, the ribosome, and numerous other small molecules, the translational system allows the interpretation of data in the form of DNA to create massively complex proteins which control and enact almost every cellular function. A natural question then, is how did this system evolve? Here we present a broad review of the existing theories of the last two decades on the origin of the translational system. We attempt to synthesize the wide variety of ideas as well as organize them into modular components, addressing the evolution of the peptide-RNA interaction, tRNA, mRNA, the ribosome, and the first proteins separately. We hope to provide both a comprehensive overview of the literature as well as a framework for future discussions and novel theories. © 2013 Springer Science+Business Media New York.
Demars B.O.L.,James Hutton Institute |
Manson J.R.,Pomona College
Water Research | Year: 2013
The gas transfer velocity (KL) and related gas transfer coefficient (k2 = KLA/V, with A, area and V, volume) at the air-water interface are critical parameters in all gas flux studies such as green house gas emission, whole stream metabolism or industrial processes. So far, there is no theoretical model able to provide accurate estimation of gas transfer in streams. Hence, reaeration is often estimated with empirical equations. The gas transfer velocity need then to be corrected with a temperature coefficient θ = 1.0241. Yet several studies have long reported variation in θ with temperature and 'turbulence' of water (i.e. θ is not a constant). Here we re-investigate thoroughly a key theoretical model (Dobbins model) in detail after discovering important discrepancies. We then compare it with other theoretical models derived from a wide range of hydraulic behaviours (rigid to free continuous surface water, wave and waterfalls with bubbles). The results of the Dobbins model were found to hold, at least theoretically in the light of recent advances in hydraulics, although the more comprehensive results in this study highlighted a higher degree of complexity in θ's behaviour. According to the Dobbins model, the temperature coefficient θ, could vary from 1.005 to 1.042 within a temperature range of 0-35 °C and wide range of gas transfer velocities, i.e. 'turbulence' condition (0.005 < KL < 1.28 cm min-1). No other theoretical models showed any significant variability in θ with change in 'turbulence', and only modest variability in θ with change in temperature. However, the other theoretical models did not have the same temperature coefficient θ (with 1.000 < θ < 1.056 within 0-35 °C). A model integrating turbulence and bubble mediated gas transfer velocities suggested a lower temperature dependence for bubble (1.013<θ < 1.017) than turbulence (1.023<θ < 1.031) mediated processes. As it stands, the effect of turbulence on the temperature dependence of gas transfer at the air-water interface has still to be clarified, although many models simulate different flow conditions which may explain some of the observed discrepancies. We suggest that the temperature dependence curves produced by the Dobbins model may be used tentatively as a simple theoretical guide for streams with free surface water but not self-aerated flows encountered in whitewater rapids, cascades or weirs. Greater awareness of the different models and conditions of applications should help choosing an appropriate correction. Three case studies investigated the effect of the temperature coefficient on reaeration and stream metabolism (photosynthesis and respiration). In practice, the temperature correction may be an important parameter under constant turbulence conditions, but as the range in turbulence increases, the role of temperature may become negligible in determining KL, whatever the temperature correction. The theoretical models reviewed here are also useful references to correct KL values determined using a reference tracer gas to a second species of interest. © 2012 Elsevier Ltd.
Agency: NSF | Branch: Continuing grant | Program: | Phase: LAW AND SOCIAL SCIENCES | Award Amount: 75.00K | Year: 2016
Sociolegal scholarship has shown how law schools and training programs can serve as support structures that provide critical intellectual, social, and material resources for movements seeking to influence the law. While this scholarship establishes that these institutions are a necessary precondition for change, it leaves open an important question. Namely, are there types of support structures that are more or less effective at producing and facilitating the transfer of these valuable resources to and within movements? Contemporary legal movements provide a unique opportunity to address this question, as their patrons have, since the late-1990s, invested in support institutions representative of three different types - Leveraging, Supplemental, and Parallel Alternative Structures.
This study uses this variation to help forward two models for understanding and assessing the efficacy of different support structure strategies. It does this by collecting and aggregating institutional data from three law schools and one legal training program at the heart of these contemporary legal movements. PIs will supplement these data with evidence gathered from personal interviews, participant observation, and an original survey. PIs will analyze these data both qualitatively and quantitatively, with the primary methods involving interpretive data analysis and network mapping. This project will provide important insights for scholars and practitioners and will have at least two significant impacts. First, through the development of new models for understanding movements, this project will make a theoretical contribution to the scholarly literature on support structures, legal mobilization, and social movements. Secondly, policy activists who have learned that a support structure is necessary for legal change have little guidance from the literature as to what kinds of support structures will best facilitate the transfer of resources between their movement and policy demanders. This project will help inform this important policy and scholarly conversation.
Agency: NSF | Branch: Standard Grant | Program: | Phase: SEDIMENTARY GEO & PALEOBIOLOGY | Award Amount: 148.29K | Year: 2016
The Cambrian ?explosion? was a singular event in the history of life on Earth. This episode, which saw the origin and rapid diversification of almost all major groups of animals (phyla), serves to divide the entire geologic record into two parts, the Precambrian and Phanerozoic Eons. By far, the best records of this event come from a handful of exceptional fossil deposits that preserve the ?soft?, non-biomineralized tissues of organisms that normally leave no trace in the fossil record. Such deposits offer not only a remarkable view of the early patterns of evolution, but have helped to reveal the basic structure of the animal family tree. Recently, the most important Cambrian fossil assemblage discovered in decades was reported from the Burgess Shale near Marble Canyon.
This project seeks to provide baseline characterization of the new fossil assemblage and its geological and geochemical context though a multi-disciplinary approach, which will provide hands on training for undergraduates and a postdoctoral scholar. The goals of the project are: 1. to document the geographic extent and composition of the new fossil fauna by exploration and quarrying; 2. to use geochemical and sedimentologic methods to reconstruct the nature of ancient environments in which these fossil assemblages thrived; 3. to develop a strontium isotope chronology linking all Burgess Shale localities in relative time, and; 4. to determine the origin of the Cathedral Escarpment, an enigmatic topographic feature that is central to the Geologic history of the Burgess Shale.