California Institute Of Technology Research Articles

CO Emission, Molecular Gas, and Metallicity in Main-sequence Star-forming Galaxies at z ∼ 2.3* *The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support

We present observations of CO(3−2) in 13 main-sequence z = 2.0–2.5 star-forming galaxies at that span a wide range in metallicity (O/H) based on rest-optical spectroscopy. We find that /SFR decreases with decreasing metallicity, implying that the CO luminosity per unit gas mass is lower in low-metallicity galaxies at z ∼ 2. We constrain the CO-to-H2 conversion factor (α CO) and find that α CO inversely correlates with metallicity at z ∼ 2. We derive molecular gas masses (M mol) and characterize the relations among M *, SFR, M mol, and metallicity. At z ∼ 2, M mol increases and the molecular gas fraction (M mol/M *) decreases with increasing M *, with a significant secondary dependence on SFR. Galaxies at z ∼ 2 lie on a near-linear molecular KS law that is well-described by a constant depletion time of 700 Myr. We find that the scatter about the mean SFR−M *, O/H−M *, and M mol−M * relations is correlated such that, at fixed M *, z ∼ 2 galaxies with larger M mol have higher SFR and lower O/H. We thus confirm the existence of a fundamental metallicity relation at z ∼ 2, where O/H is inversely correlated with both SFR and M mol at fixed M *. These results suggest that the scatter of the z ∼ 2 star-forming main sequence, mass–metallicity relation, and M mol–M * relation are primarily driven by stochastic variations in gas inflow rates. We place constraints on the mass loading of galactic outflows and perform a metal budget analysis, finding that massive z ∼ 2 star-forming galaxies retain only 30% of metals produced, implying that a large mass of metals resides in the circumgalactic medium.

Perspectives and opportunities: a molecular toolkit for fundamental physics and matter-wave interferometry in microgravity * *A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

The study of molecular physics using ultracold gases has provided a unique probe into the fundamental properties of nature and offers new tools for quantum technologies. In this article we outline how ultracold molecular physics in a space environment opens opportunities for (a) exploring ultra-low energy regimes of molecular physics with high efficiency, (b) providing a toolbox of capabilities for fundamental physics, and (c) enabling new classes of matter-wave interferometers with applications in precision measurement for fundamental and many-body physics.

The Research on Split-Brian and Philosophical Thinking by Sperry

Among the advances in brain research at the frontiers of contemporary science, the most notable achievement was the work of Roger W. Sperry, a professor of psychobiology at the California Institute of Technology, who was awarded the 1981 Nobel Prize in Physiology or Medicine for his work on the "split-brain man". This paper is intended to analyze the philosophy behind the split-brain. Describe Sperry's main findings about the split brain.

(Invited) Ester and Carbonate-Based Low Temperature Electrolytes for Operation of Lithium-Ion Batteries in Extreme Environments for NASA Missions

NASA continues to have an interest in developing high specific energy and high power rechargeable batteries that can operate well over a wide temperature range. Potential applications that could be enabled or enhanced by such technology include: (i) future Mars and Lunar landers, (ii) future Mars and Lunar rovers, (iii) small robotic missions, and (iv) future planetary aerial vehicles, where high specific energy, high power and wide operating temperature range is desired. Future missions to some of the distant icy moons of Jupiter and Saturn are also anticipated to benefit from improved ultra-low temperature rechargeable batteries with high specific energy.1 A number of terrestrial applications, including automotive and aviation Li-ion batteries, also benefit from having wide temperature range capability. To meet these needs, the Electrochemical Research, Technology, and Engineering Group at the Jet Propulsion Laboratory (JPL) has developed a number of low temperature Li-ion electrolytes utilizing various approaches. Broadly speaking, the performance targets of this work are to provide operation over the temperature range of +60oC to -60oC (delivering over 100 Wh/kg at -40oC at reasonable rates).This paper will provide an overview of the low temperature electrolyte development activities that have taken place at JPL, with a focus on enabling ultra-low temperature operation for extreme environments. The electrolytes evaluated included blends which contain elements of various approaches, including (i) the use of ester co-solvents, (ii) low ethylene carbonate content-based blends, (iii) the use of electrolyte additives, and (iv) the use of mixed lithium electrolyte salts. Experimental studies were performed utilizing three-electrode cells to determine the influence that the electrolyte type has upon the electrode kinetics as a function of temperature. A number of electrochemical techniques were employed to study these cells, including Electrochemical Impedance Spectroscopy (EIS), Tafel polarization, and linear micro-polarization.Improved low temperature capability has been demonstrated in small and large capacity prototype cells with a number of chemistries (i.e., NCO, NCA, NMC, LCO and LFP-based chemistries), including the ability to deliver high specific energy down to -60oC, good charge acceptance at low temperature, and high-power capability at -40oC. Prototype cells incorporating JPL developed electrolytes were obtained from a number of vendors, including (i) Eagle Pitcher Technologies-Yardney Division, (ii) Enersys/Quallion, LLC, (iii) E-One Moli Energy Ltd., (iv) Saft America, and (iv) Navitas/A123. Emphasis was devoted to establishing the charge acceptance characteristics of the cells at very low temperatures, especially below -20oC. Given that lithium plating when charging at low temperatures is a known degradation mode of Li-ion cells in general, attention was focused upon characterizing the conditions in which its likelihood may be more pronounced, determining the influence of electrolyte type, and attempting to detect its occurrence indirectly.Early generations of electrolytes have been utilized in a number of NASA missions, including the 2003 Mars Exploration Rover, 2007 Phoenix Lander, 2011 Mars Science Laboratory (MSL) Curiosity Rover, 2018 Mars InSight Lander, and a JPL/CSUN CubeSat.1-5 Previous work has also targeted improved low temperature performance of Li-ion cells for automotive applications. Current work is focused primarily upon providing higher specific energy coupled with good power characteristics at very low temperatures. Studies have also been performed demonstrating operational capability down to -90oC in some systems, and survival capability to temperatures as low as -135oC.ACKNOWLEDGEMENT The work described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA). The information in this document is pre-decisional and is provided for planning and discussion only. REFERENCES M. C. Smart, B. V. Ratnakumar, R. C. Ewell, S. Surampudi, F. Puglia, and R. Gitzendanner, Electrochimica Acta, 268, 27-40 (2018). M. C. Smart, D. Muthulingam, M. E. Lisano, S. F. Dawson, R. B. Shaw, B. T. White, A. Buonanno, C. Deroy, and R. Gitzendanner, 236th Meeting of the Electrochemical Society (ECS), Atlanta, Georgia, October 15, 2019. M. C. Smart, F. C. Krause, and J. -P. Jones, CREB Bi-Annual Meeting, University of Maryland, December 10, 2021. K. B. Chin, G. B. Bolotin, M. C. Smart, S. Katz, J. A. Flynn, N. K. Palmer, E. J. Brandon, and W. C. West, IEEE A&E Systems Magazine, 36 (5), 24-36 (2021). M. C. Smart, B. V. Ratnakumar, F. Charlie Krause, William C. West and Erik J. Brandon, 2021 Space Power Workshop (Virtual), Pasadena, CA, April 19, 2021. M. C. Smart, F. C. Krause, J. -P. Jones, C. L. Fuller, J. A. Schwartz, and B. V. Ratnakumar, 2018 Conference on Advanced Power Systems for Deep Space Exploration, Pasadena, CA, October 22-24, 2018.

MAGAZ3NE: High Stellar Velocity Dispersions for Ultramassive Quiescent Galaxies at z ≳ 3* * The spectra presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support

In this work, we publish stellar velocity dispersions, sizes, and dynamical masses for eight ultramassive galaxies (UMGs; > 11), z ≳ 3) from the Massive Ancient Galaxies At z > 3 NEar-infrared (MAGAZ3NE) Survey, more than doubling the number of such galaxies with velocity dispersion measurements at this epoch. Using the deep Keck/MOSFIRE and Keck/NIRES spectroscopy of these objects in the H and K bandpasses, we obtain large velocity dispersions of ∼400 km s−1 for most of the objects, which are some of the highest stellar velocity dispersions measured and ∼40% larger than those measured for galaxies of similar mass at z ∼ 1.7. The sizes of these objects are also smaller by a factor of 1.5–3 compared to this same z ∼ 1.7 sample. We combine these large velocity dispersions and small sizes to obtain dynamical masses. The dynamical masses are similar to the stellar masses of these galaxies, consistent with a Chabrier initial mass function (IMF). Considered alongside previous studies of massive quiescent galaxies across 0.2 < z < 4.0, there is evidence for an evolution in the relation between the dynamical mass–stellar mass ratio and velocity dispersion as a function of redshift. This implies an IMF with fewer low-mass stars (e.g., Chabrier IMF) for massive quiescent galaxies at higher redshifts in conflict with the bottom-heavy IMF (e.g., Salpeter IMF) found in their likely z ∼ 0 descendants, though a number of alternative explanations such as a different dynamical structure or significant rotation are not ruled out. Similar to data at lower redshifts, we see evidence for an increase of IMF normalization with velocity dispersion, though the z ≳ 3 trend is steeper than that for z ∼ 0.2 early-type galaxies and offset to lower dynamical-to-stellar mass ratios.

SCExAO and Keck Direct Imaging Discovery of a Low-mass Companion Around the Accelerating F5 Star HIP 5319* *Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California

We present the direct imaging discovery of a low-mass companion to the nearby accelerating F star, HIP 5319, using SCExAO coupled with the CHARIS, VAMPIRES, and MEC instruments in addition to Keck/NIRC2 imaging. CHARIS JHK (1.1–2.4 μm) spectroscopic data combined with VAMPIRES 750 nm, MEC Y, and NIRC2 L p photometry is best matched by an M3–M7 object with an effective temperature of T = 3200 K and surface gravity log(g) = 5.5. Using the relative astrometry for HIP 5319 B from CHARIS and NIRC2, and absolute astrometry for the primary from Gaia and Hipparcos, and adopting a log-normal prior assumption for the companion mass, we measure a dynamical mass for HIP 5319 B of , a semimajor axis of au, an inclination of degrees, and an eccentricity of . However, using an alternate prior for our dynamical model yields a much higher mass of . Using data taken with the LCOGT NRES instrument we also show that the primary HIP 5319 A is a single star in contrast to previous characterizations of the system as a spectroscopic binary. This work underscores the importance of assumed priors in dynamical models for companions detected with imaging and astrometry, and the need to have an updated inventory of system measurements.

Women Chemists Committee honors award winners

The American Chemical Society’s Women Chemists Committee (WCC) honored several awardees during the ACS Fall 2022 meeting in Chicago. The 2022 Overcoming Challenges Award was presented to Riley Atrops , a recent graduate from California State University Channel Islands. This award is given to undergraduate women chemistry students who have overcome significant obstacles in their pursuit of success in the field of chemistry. Atrops survived a serious automobile accident when she was a child and was diagnosed with a tumor as an undergraduate. The 2022 Merck Research Award, sponsored by Merck & Co, was awarded to eight third- and fourth-year women graduate students. The recipients are Maria Aguilera , University of Rochester; Maria Adrover Castellano , University of Michigan; Sara Dibrell , California Institute of Technology; Olivia Garry , Princeton University; Zhuojun Huang , Stanford University; Irene Manning , University of North Carolina at Chapel Hill; Alena Vasquez , Scripps

The 2022 Emerging Leader in Molecular Spectroscopy Award

This year’s molecular spectroscopy award recipient is Lu Wei, an assistant professor of chemistry at the California Institute of Technology in Pasadena, California. From her days as a graduate student at Columbia University, Wei’s work has focused on the development and application of stimulated Raman scattering (SRS) microscopy for bioanalysis, spectroscopy-informed design of vibrational imaging probes, and sample-engineering strategies.

A hapless mathematical contribution to biology : Chromosome inversions in Drosophila, 1937-1941.

This is the story, told in the light of a new analysis of historical data, of a mathematical biology problem that was explored in the 1930s in Thomas Morgan's laboratory at the California Institute of Technology. It is one of the early developments of evolutionary genetics and quantitative phylogeny, and deals with the identification and counting of chromosomal inversions in Drosophila species from comparisons of genetic maps. A re-analysis of the data produced in the 1930s using current mathematics and computational technologies reveals how a team of biologists, with the help of a renowned mathematician and against their first intuition, came to an erroneous conclusion regarding the presence of phylogenetic signals in gene arrangements. This example illustrates two different aspects of a same piece: (1) the appearance of a mathematical in biology problem solved with the development of a combinatorial algorithm, which was unusual at the time, and (2) the role of errors in scientific activity. Also underlying is the possible influence of computational complexity in understanding the directions of research in biology.

Personalized cancer vaccines: more is more?

We caught up with Geneos Therapeutics Founder Niranjan Sardesai to learn more about the company’s highly personalized cancer vaccines, which target up to 40 tumor neoantigens in a single DNA plasmid vaccine.Niranjan Sardesai is Founder, President, and CEO of Geneos Therapeutics. He is recognized as an expert in nucleic acid vaccines and immunotherapies and led the development of the DNA medicines technologies that are at the core of Geneos’ GT-EPIC™ platform. Previously he served as Chief Operating Officer and Head of R&amp;D at Inovio Pharmaceuticals. He was responsible for the development pipeline and led the capital-raising efforts for the company via strategic out-licensing of pipeline products to secure major licensing deals totaling over $1 Bn and securing over $150M in non-dilutive grants and contracts from funding agencies. Dr. Sardesai received a PhD in Chemistry from the California Institute of Technology and an MBA from the Wharton School of the University of Pennsylvania, where he was the recipient of the Shils-Zeidman Award in Entrepreneurship

David Romney

When faced with a challenge, David Romney likes to dive right into the deep end. After he struggled with introductory chemistry as an undergraduate at the California Institute of Technology, he decided that the best way to overcome his frustration with the course was to become a chemistry major. As a graduate student, he wrestled with chemical syntheses of amino acids, so he devoted his postdoc to finding a better way to make these molecules using engineered enzymes. Romney even plunges into his hobbies headfirst: he taught himself how to play electric guitar and now loves to shred a good heavy-metal riff. But perhaps the best illustration of Romney’s willingness to leap into a new enterprise is his most recent career move. Although he knew nothing about business or doing chemistry on large scales, in 2019 Romney cofounded Aralez Bio —a company that uses engineered enzymes to churn out kilograms

Kinematics and Metallicity of Red Giant Branch Stars in the Northeast Shelf of M31* *The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support

We obtained Keck/DEIMOS spectra of 556 individual red giant branch stars in four spectroscopic fields spanning 13−31 projected kpc along the northeast (NE) shelf of M31. We present the first detection of a complete wedge pattern in the space of projected M31-centric radial distance versus line-of-sight velocity for this feature, which includes the returning stream component of the shelf. This wedge pattern agrees with expectations of a tidal shell formed in a radial merger and provides strong evidence in favor of predictions of Giant Stellar Stream (GSS) formation models in which the NE shelf originates from the second orbital wrap of the tidal debris. The observed concentric wedge patterns of the NE, west (W), and southeast (SE) shelves corroborate this interpretation independently of the models. We do not detect a kinematical signature in the NE shelf region corresponding to an intact progenitor core, favoring GSS formation models in which the progenitor is completely disrupted. The shelf’s photometric metallicity ([Fe/H]phot) distribution implies that it is dominated by tidal material, as opposed to the phase-mixed stellar halo or the disk. The metallicity distribution ([Fe/H]phot = −0.42 ± 0.01) also matches the GSS, and consequently the W and SE shelves, further supporting a direct physical association between the tidal features.

Fossil biomolecules suggest which dinosaurs were warm or cold blooded

People once assumed that dinosaurs were cold-blooded reptiles. That understanding has morphed over the last 50 years or so, and we now think that many dinosaurs were warm blooded and birdlike . New research offers some nuance. Using fossilized biomolecules, researchers have determined that some dinosaurs were warm and others cold blooded ( Nature 2022 , DOI: 10.1038/s41586-022-04770-6 ). The scientists’ estimates of the metabolic rates of dinosaurs also provide insights into the likely lifestyles of certain ones. Finding metabolic rates for living animals is easy. For example, we can put a hamster on a treadmill and measure how much oxygen it breathes relative to its body mass for a given period, says Jasmina Wiemann , a molecular paleobiologist at the California Institute of Technology. “We can’t do this with a Tyrannosaurus rex .” The solution, she says, was to look for metabolic markers in fossils. The oxidation reactions that

In the field: an interview with Harald Wolf

Harald Wolf has recently retired as a Professor at the University of Ulm, Germany, where he investigated navigation, locomotor control and sensorimotor integration in invertebrates. After completing his diploma in biology in 1980 at the Technical University Darmstadt, Germany, he undertook a PhD with Otto von Helversen at Erlangen University, Germany, and postdocs with Keir Pearson at Edmonton University, Canada, and Werner Rathmayer at Constance University, Germany. He then received a Heisenberg Fellowship to complete research at Constance University and the California Institute of Technology, USA, before completing a 2-year lectureship at the University of Zurich, Switzerland.

One on one with Carolyn L. Ladd

After completing their PhD at the University of Montreal and a postdoc at the California Institute of Technology, Carolyn L. Ladd began working for Dow, developing sustainable technologies to reduce the carbon footprint of industrial processes. Kirstin S. Bode spoke with them about Ladd’s career path and queer activism. This interview has been edited for length and clarity. Kirstin S. Bode: Can you tell me a little bit about the research you did for your PhD? Carolyn L. Ladd: For my PhD, I worked for André Charette at the University of Montreal. I spent some time working on C–H activation, specifically of cyclopropanes, as well as asymmetric catalysis. I guess that’s when I first fell in love with homogeneous catalysis, and it also made me fall in love with palladium, my absolute favorite transition metal. That experience kind of just got me hooked into doing that type of work. KSB:

Working at the interface

Peter B. Dervan started studying DNA through the lens of organic chemistry before the tools for sequencing and synthesizing it existed. He embraced risk and laid the groundwork for what became the field of chemical biology. Dervan’s team twice discovered ways to recognize specific DNA sequences—first in the minor groove and then in the major groove. In addition to his research, he helped found Gilead Sciences, served on the Scientific Advisory Board of the Welch Foundation for 33 years, and was a trustee of Yale University. In 1975, Peter B. Dervan, then an assistant professor of chemistry at the California Institute of Technology, switched his research focus from physical organic chemistry to DNA. That doesn’t sound remarkable unless you realize what tools weren’t available at the time. There was no easy way to synthesize DNA and no easy way to sequence it. There wasn’t even a high resolution crystal structure

From ‘The Body Politic’ to ‘The National Interest’: English State Formation in Comparative and Historical Perspective (An Argument Concerning ‘Politically Organized Subjection’)

AbstractPreviously unpublished, “From the Body Politic to the National Interest” was presented at the Mellon Symposium in Historical Anthropology at California Institute of Technology in May 1987. We are publishing it in the Journal of Historical Sociology for the first time to honor Philip Corrigan's memory. The essay was an attempt to expand upon arguments in Philip Corrigan and Derek Sayer, The Great Arch: English State Formation as Cultural Revolution (1985) under two main rubrics: (1) “routines and rituals of rule” and (2) “regulated representations and the making of ‘the’ public.” In both cases we went beyond our treatment of these topics in The Great Arch, to which this paper should be seen as a supplement.

The Power of Phosphate

This paper concerns the development of a central tenet of modern biochemistry: that cellular metabolism coordinates biological energy supply through the cyclical making and breaking of “energy-rich” phosphate bonds. This interpretation of intermediary metabolism was comprehensively set forth in two review articles published nearly simultaneously (though independently) in early 1941 by German biochemist Fritz Lipmann and Danish biochemist Herman Kalckar. Lipmann and Kalckar first met in the early 1930s in Copenhagen, where they were in frequent contact until 1939, when both left Denmark. Despite the similar claims advanced in Lipmann’s and Kalckar’s reviews, the two men’s presentations differed substantially with respect to their descriptions of “energy-rich” phosphate bonds and their target audiences. In order to explore the circumstances behind these divergences, this paper utilizes a “parallel lives” approach. By analyzing Lipmann’s and Kalckar’s lives in parallel, particular institutional contexts emerge as having been especially significant in shaping their differing interpretations of the power of phosphate bonds. The period that Lipmann spent in muscle researcher Otto Meyerhof’s laboratory (1927–30) conditioned his physiological interpretation of the role of phosphate bonds in cellular energy metabolism. Kalckar’s time at California Institute of Technology (1939–40)—where he was in regular communication with chemists such as Linus Pauling—played the most significant role in his decision to present the power of phosphate bonds from a chemical perspective. Ultimately, an examination of the life stories behind Lipmann’s and Kalckar’s 1941 reviews illuminates how older physiological perspectives were combined with recent advances in theoretical chemistry to explain how energy flows through living organisms.

Thirty Meter Telescope (TMT) Research as Reflected in Web of Science: A Study

ABSTRACT The study attempts to identify the Thirty Meter Telescope (TMT) literature indexed in the World’s most preferable database, i.e. Web of Science by Clarivate Analytics. We retrieved 443 records during the period 2003–2019 and analyzed. Among the 443 records, the primary document type was “Proceedings Paper” with 324 (73.13%) followed by “Article” with 107 (24.153%). Thirty Meter Telescope Observatory topped and stood in first rank with 179 (40.40%) papers, California Institute of Technology was second rank with 91 (20.54%) and third rank was Herzberg Institute of Astrophysics with 57 (12.86%). T.G. Herrio published 54 (12.190%) papers got first position followed by B. Ellerbroek with 50 (11.287%) papers received second position and J.P. Veran with 44 (9.932%) articles placed in third position. The study also analyzed authorship pattern, degree of collaboration, highly preferred journal to publish their research works, most productive country, funding agencies, highly cited articles and H-index.

Sensitivity Analysis of Thermochemical Kinetics Modeling for Hypersonic Air Flows

A computational analysis is used to model Mach 5 and Mach 7 flows over a cylinder, where freestream properties are representative of experiments to be conducted in the Hypervelocity Expansion Tube at the California Institute of Technology. A sensitivity analysis is conducted using the polynomial chaos expansion method, and Sobol indices are used to determine which thermochemical nonequilibrium phenomena most affect various quantities of interest. The results show that the dissociation of molecular oxygen through interaction with molecular nitrogen and with atomic oxygen reactions dominates the determination of surface pressure, surface heat transfer, drag, heating rate, and rotational temperature, whereas the first two Zeldovich reactions dominate the surface number density of NO. The reaction is found to be less important than other reactions. Surface pressure and drag are also shown to be relatively insensitive overall. The results also indicate flow separation and recirculation near the trailing edge of the cylinder. These findings may help diagnostic developments to lower discrepancies between computation and experiments, and indicate that the Hypervelocity Expansion Tube experiments should be successful for the future evaluation of thermochemistry modeling.