California Institute Of Technology Research Articles

Approximation hierarchies for copositive cone over symmetric cone and their comparison

We first provide an inner-approximation hierarchy described by a sum-of-squares (SOS) constraint for the copositive (COP) cone over a general symmetric cone. The hierarchy is a generalization of that proposed by Parrilo (Structured semidefinite programs and semialgebraic geometry methods in Robustness and optimization, Ph.D. Thesis, California Institute of Technology, Pasadena, CA, 2000) for the usual COP cone (over a nonnegative orthant). We also discuss its dual. Second, we characterize the COP cone over a symmetric cone using the usual COP cone. By replacing the usual COP cone appearing in this characterization with the inner- or outer-approximation hierarchy provided by de Klerk and Pasechnik (SIAM J Optim 12(4):875–892, https://doi.org/10.1137/S1052623401383248, 2002) or Yıldırım (Optim Methods Softw 27(1):155–173, https://doi.org/10.1080/10556788.2010.540014, 2012), we obtain an inner- or outer-approximation hierarchy described by semidefinite but not by SOS constraints for the COP matrix cone over the direct product of a nonnegative orthant and a second-order cone. We then compare them with the existing hierarchies provided by Zuluaga et al. (SIAM J Optim 16(4):1076–1091, https://doi.org/10.1137/03060151X, 2006) and Lasserre (Math Program 144:265–276, https://doi.org/10.1007/s10107-013-0632-5, 2014). Theoretical and numerical examinations imply that we can numerically increase a depth parameter, which determines an approximation accuracy, in the approximation hierarchies derived from de Klerk and Pasechnik (SIAM J Optim 12(4):875–892, https://doi.org/10.1137/S1052623401383248, 2002) and Yıldırım (Optim Methods Softw 27(1):155–173, https://doi.org/10.1080/10556788.2010.540014, 2012), particularly when the nonnegative orthant is small. In such a case, the approximation hierarchy derived from Yıldırım (Optim Methods Softw 27(1):155–173, https://doi.org/10.1080/10556788.2010.540014, 2012) can yield nearly optimal values numerically. Combining the proposed approximation hierarchies with existing ones, we can evaluate the optimal value of COP programming problems more accurately and efficiently.

The Circumgalactic Medium of Extreme Emission Line Galaxies at z∼2: Resolved Spectroscopy and Radiative Transfer Modeling of Spatially Extended Lyα Emission in the KBSS-KCWI Survey* *Based on data 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 NASA, and was made possible by the generous financial support of the W.M. Keck Foundation.

The resonantly scattered Lyα line illuminates the extended halos of neutral hydrogen in the circumgalactic medium of galaxies. We present integral field Keck Cosmic Web Imager observations of double-peaked, spatially extended Lyα emission in 12 relatively low-mass (M ⋆ ∼ 109 M⊙) z ∼ 2 galaxies characterized by extreme nebular emission lines. Using individual spaxels and small bins as well as radially binned profiles of larger regions, we find that for most objects in the sample the Lyα blue-to-red peak ratio increases, the peak separation decreases, and the fraction of flux emerging at line center increases with radius. We use new radiative transfer simulations to model each galaxy with a clumpy, multiphase outflow with radially varying outflow velocity, and self-consistently apply the same velocity model to the low-ionization interstellar absorption lines. These models reproduce the trends of peak ratio, peak separation, and trough depth with radius, and broadly reconcile outflow velocities inferred from Lyα and absorption lines. The galaxies in our sample are well-described by a model in which neutral, outflowing clumps are embedded in a hotter, more highly ionized inter-clump medium (ICM), whose residual neutral content produces absorption at the systemic redshift. The peak ratio, peak separation, and trough flux fraction are primarily governed by the line-of-sight component of the outflow velocity, the H i column density, and the residual neutral density in the ICM respectively. The azimuthal asymmetries in the line profile further suggest nonradial gas motions at large radii and variations in the H i column density in the outer halos.

On the Metallicities and Kinematics of the Circumgalactic Media of Damped Lyα Systems at z ∼ 2.5* * 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 of the W. M. Keck Foundation.

We use medium- and high-resolution spectroscopy of close pairs of quasars to analyze the circumgalactic medium (CGM) surrounding 32 damped Lyα absorption systems (DLAs). The primary quasar sightline in each pair probes an intervening DLA in the redshift range 1.6 < z abs < 3.5, such that the secondary sightline probes absorption from Lyα and a large suite of metal-line transitions (including O i, C ii, C iv, Si ii, and Si iv) in the DLA host galaxy’s CGM at transverse distances 24 kpc ≤ R ⊥ ≤ 284 kpc. Analysis of Lyα in the CGM sightlines shows an anticorrelation between R ⊥ and H i column density (N HI) with 99.8% confidence, similar to that observed around luminous galaxies. The incidences of C ii and Si ii with N > 1013 cm−2 within 100 kpc of DLAs are larger by 2σ than those measured in the CGM of Lyman break galaxies (C f (N CII ) > 0.89 and ). Metallicity constraints derived from ionic ratios for nine CGM systems with negligible ionization corrections and N HI > 1018.5 cm−2 show a significant degree of scatter (with metallicities/limits across the range ), suggesting inhomogeneity in the metal distribution in these environments. Velocity widths of C iv λ1548 and low-ionization metal species in the DLA versus CGM sightlines are strongly (>2σ) correlated, suggesting that they trace the potential well of the host halo over R ⊥ ≲ 300 kpc scales. At the same time, velocity centroids for C iv λ1548 differ in DLA versus CGM sightlines by >100 km s−1 for ∼50% of velocity components, but few components have velocities that would exceed the escape velocity assuming dark matter host halos of ≥1012 M ⊙.

The Impact of Star-formation-rate Surface Density on the Electron Density and Ionization Parameter of High-redshift Galaxies* *Based on data 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 NASA, and was made possible by the generous financial support of the W.M. Keck Foundation.

We use the large spectroscopic data set of the MOSFIRE Deep Evolution Field survey to investigate some of the key factors responsible for the elevated ionization parameters (U) inferred for high-redshift galaxies, focusing in particular on the role of star-formation-rate surface density (ΣSFR). Using a sample of 317 galaxies with spectroscopic redshifts z spec ≃ 1.9–3.7, we construct composite rest-frame optical spectra in bins of ΣSFR and infer electron densities, n e, using the ratio of the [O ii] λ λ3727, 3730 doublet. Our analysis suggests a significant (≃3σ) correlation between n e and ΣSFR. We further find significant correlations between U and ΣSFR for composite spectra of a subsample of 113 galaxies, and for a smaller sample of 25 individual galaxies with inferences of U. The increase in n e—and possibly also the volume filling factor of dense clumps in H ii regions—with ΣSFR appear to be important factors in explaining the relationship between U and ΣSFR. Further, the increase in n e and SFR with redshift at a fixed stellar mass can account for most of the redshift evolution of U. These results suggest that the gas density, which sets n e and the overall level of star formation activity, may play a more important role than metallicity evolution in explaining the elevated ionization parameters of high-redshift galaxies.

Laser Absorption Sensor Targeting Potassium for Hypersonic Velocity, Temperature, and Enthalpy Measurements

A laser absorption-based sensor for hypersonic gas flows was developed, targeting the spectroscopic transition of atomic potassium near 770 nm. The sensor applies rapid-scanning tunable diode laser absorption spectroscopy to measure velocity from the Doppler shift and to infer temperature from the hyperfine-split transition lineshape. This sensor measured velocities and temperatures across three distinct conditions and six shots in the Hypervelocity Expansion Tube at the California Institute of Technology. Velocity and temperature were sampled at intervals, and temperature measurements were validated with a supplementary laser absorption-based sensor targeting carbon dioxide transitions near . Measured velocities across the three conditions ranged from 3.3 to 4.4 km/s, and measured temperatures ranged from 900 to 1600 K. The combined measurements were used to infer the freestream specific total enthalpy, which ranged from 7 to 10 MJ/kg. Because atomic potassium naturally forms in the test gas of many hypersonic impulse facilities, similar sensors may be widely applicable to facility characterization.

Astrobiology eXploration at Enceladus (AXE): A New Frontiers Mission Concept Study

The Saturnian moon Enceladus presents a unique opportunity to sample the contents of a subsurface liquid water ocean in situ via the continuous plume formed over its south polar terrain using a multi-flyby mission architecture. Previous analyses of the plume’s composition by Cassini revealed an energy-rich system laden with salts and organic compounds, representing an environment containing most of the ingredients for life as we know it. Following in the footsteps of the Cassini-Huygens mission, we present Astrobiology eXploration at Enceladus (AXE), a New Frontiers class Enceladus mission concept study carried out during the 2021 NASA Planetary Science Summer School program at the Jet Propulsion Laboratory, California Institute of Technology. We demonstrate that a scientifically compelling geophysical and life-detection mission to Enceladus can be carried out within the constraints of a New Frontiers-5 cost cap using a modest instrument suite, requiring only a narrow angle, high-resolution telescopic imager, a mass spectrometer, and a high-gain antenna for radio communications and gravity science measurements. Using a multi-flyby mission architecture, AXE would evaluate the habitability and potential for life at Enceladus through a synergistic combination of in situ chemical analysis measurements aimed at directly detecting the presence of molecular biosignatures, along with geophysical and geomorphological investigations to contextualize chemical biosignatures and further evaluate the habitability of Enceladus over geologic time.

Reactions

PEOPLE Reactions ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2023, 101 (17), p 3May 29, 2023Cite this:C&EN 101, 17, 3Letters to the editorRecognizing more contributors to DNA discoveryIn Wikipedia, there are 21 scientists listed who made significant contributions to determining the structure of DNA. In recent decades the focus has been on the contributions of only 3 of those individuals, to the exclusion of others (C&EN, May 1, 2023, page 6). For example, a recent book on paleogenetics attributes this discovery solely to James Watson and Francis Crick using Rosalind Franklin’s data. While Watson and Crick did derive a complete model for the structure of DNA, they were greatly assisted by information from multiple sources.Florence Bell obtained the first diffraction image of DNA in 1938 while working with William Astbury. Their publication described DNA as being like a “pile of pennies” with a periodicity of 3.3–3.4 Å along the axis.The group at King’s College London consisted of John Randall (head), Maurice Wilkins (assistant head), Alexander Stokes (lecturer), Franklin (postdoctoral researcher), Herbert Wilson (postdoctoral researcher), and Raymond Gosling (PhD student). Wilkins and Gosling obtained an X-ray diffraction image of the A-form of DNA in 1950; Stokes performed theoretical calculations for the expected diffraction pattern of a helical structure and compared it with the diffraction image to confirm that the structure was indeed helical (with C2 symmetry). Stokes was therefore the first person to identify the helicity associated with the backbone of DNA. Subsequent work by Franklin and Gosling in 1951–52 provided a much more detailed analysis of the sodium deoxyribophosphate backbone of DNA.Information on the purine-pyrimidine hydrogen-bonded base pairs, which contain the coded genetic information in DNA, came from Erwin Chargaff’s studies of the ratios of the specific bases in a range of DNA samples from different sources; currently these results are formulated as Chargaff’s rules (published in 1952).Jerry Donohue was a visiting scientist at the University of Cambridge when Watson and Crick were attempting to build a purine-pyrimidine dimer model. Donohue had studied hydrogen bonding in organic crystals at the California Institute of Technology (PhD under Linus Pauling) and helped significantly in the development of an accurate dimer model.Unravelling the Double Helix: The Lost Heroes of DNA, by Gareth Williams, gives a nicely detailed chronology of the contributions of the many scientists involved in this discovery.Ralph A. WhitneyKingston, OntarioThe supramolecular factor in AIThe use of artificial intelligence is now receiving considerable attention by the pharmaceutical industry as an alternative to classic approaches toward drug design. Here, machines that mimic human intelligence are being asked to rapidly identify new drug candidates. One significant factor that I believe has been overlooked by AI, and by virtually all other drug design approaches, is the supramolecular factor. Specifically, what I’m referring to is the difference in the biological action of agents that function as single molecules versus ones that function as a collection of these molecules—that is, as aggregates.To illustrate what I’m talking about, consider the known properties of amphotericin B. This drug has served as the gold standard for treating life-threatening fungal infections for the past 50 years. It has also earned the reputation of being one of the most toxic drugs used in modern medicine. Indeed, physicians often refer to amphotericin B as “amphoterrible.” In laboratory studies by Jacques Bolard and coworkers in Paris, it has been shown that single molecules of amphotericin B are highly selective in destroying fungal cells over red blood cells, while aggregates of this drug readily destroy both cell types. This fact by itself can explain why amphotericin B is so toxic when used therapeutically. Specifically, aggregates of this agent may be making a major contribution to its biological action. Consistent with this explanation, we have found that synthetic derivatives of amphotericin B that exhibit a reduced tendency to aggregate are more selective in destroying fungal cells and are less toxic, according to laboratory and animal studies. The fact that similar behavior has also been reported for certain antibacterial agents—in which single molecules favor the destruction of bacterial cells over red blood cells while aggregates readily destroy both types of cells—implies that this dichotomy is likely to reflect a general and heretofore unrecognized phenomenon. In principle, this could have direct relevance not only for the design of new antibiotics that are sorely needed but also for the design of other classes of drugs, such as novel anticancer agents. If this proves to be the case, then improvements in drug design should be possible using databases and drug design principles that minimize the tendency of biologically active agents to aggregate—that is, by taking the supramolecular factor into account.Steven L. RegenBethlehem, Pennsylvania CorrectionMay 15/22, 2023, page 32: The Talented 12 profile of Stacy Malaker has an incorrect photo credit. The photographer is Andrew Cortellini, not courtesy of Susannah Banziger.

Raúl Hernández Sánchez

As a young boy growing up in Chihuahua, Mexico, Raúl Hernández Sánchez was a fan of the iconic wrestler El Santo. In dozens of movies, the masked luchador battled multifarious foes, including evil scientists whose secret laboratories were filled with bizarre equipment and fuming beakers. Those scenes captured the boy’s imagination: “I was 8 years old, thinking, ‘I would like to be working there!’ ” he says with a laugh. Fortunately for us, the lab he now leads at Rice University is focused not on world domination but world preservation. “I’m trying to use supramolecular systems to tackle sustainability problems,” Hernández Sánchez says. His molecular assemblies are already showing promise in purifying water and helping generate hydrogen. Hernández Sánchez began studying chemistry at the Monterrey Institute of Technology and Higher Education. But it was a summer internship at the California Institute of Technology, where he worked on a proton-conducting material used

The Direct-method Oxygen Abundance of Typical Dwarf Galaxies at Cosmic High Noon∗ ∗ 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 of the W. M. Keck Foundation. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with programs #9289, #11710, #11802, #12201, #12931, #13389, #13498, #13504.

We present a Keck/MOSFIRE rest-optical composite spectrum of 16 typical gravitationally lensed star-forming dwarf galaxies at 1.7 ≲ z ≲ 2.6 (z mean = 2.30), all chosen independent of emission-line strength. These galaxies have a median stellar mass of and a median star formation rate of . We measure the faint electron-temperature-sensitive [O iii] λ4363 emission line at 2.5σ (4.1σ) significance when considering a bootstrapped (statistical-only) uncertainty spectrum. This yields a direct-method oxygen abundance of (). We investigate the applicability at high z of locally calibrated oxygen-based strong-line metallicity relations, finding that the local reference calibrations of Bian et al. best reproduce (≲0.12 dex) our composite metallicity at fixed strong-line ratio. At fixed M *, our composite is well represented by the z ∼ 2.3 direct-method stellar mass—gas-phase metallicity relation (MZR) of Sanders et al. When comparing to predicted MZRs from the IllustrisTNG and FIRE simulations, having recalculated our stellar masses with more realistic nonparametric star formation histories , we find excellent agreement with the FIRE MZR. Our composite is consistent with no metallicity evolution, at fixed M * and SFR, of the locally defined fundamental metallicity relation. We measure the doublet ratio [O ii] λ3729/[O ii] λ3726 = 1.56 ± 0.32 (1.51 ± 0.12) and a corresponding electron density of () when considering the bootstrapped (statistical-only) error spectrum. This result suggests that lower-mass galaxies have lower densities than higher-mass galaxies at z ∼ 2.

Uranium Abundances and Ages of r-process Enhanced Stars with Novel U ii Lines* *Some of 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 of the W. M. Keck Foundation. Additionally, this work is based on observations made with ESO Telescopes at the La Silla Paranal Observatory under program IDs 275.D-5028(A), 077.D-0453(A), and 165.N-0276(A). This paper also includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile.

The ages of the oldest stars shed light on the birth, chemical enrichment, and chemical evolution of the universe. Nucleocosmochronometry provides an avenue to determining the ages of these stars independent from stellar-evolution models. The uranium abundance, which can be determined for metal-poor r-process enhanced (RPE) stars, has been known to constitute one of the most robust chronometers known. So far, U abundance determination has used a single U ii line at λ3859 Å. Consequently, U abundance has been reliably determined for only five RPE stars. Here, we present the first homogeneous U abundance analysis of four RPE stars using two novel U ii lines at λ4050 Å and λ4090 Å, in addition to the canonical λ3859 Å line. We find that the U ii lines at λ4050 Å and λ4090 Å are reliable and render U abundances in agreement with the λ3859 U abundance, for all of the stars. We, thus, determine revised U abundances for RPE stars, 2MASS J09544277+5246414, RAVE J203843.2–002333, HE 1523–0901, and CS 31082–001, using multiple U ii lines. We also provide nucleocosmochronometric ages of these stars based on the newly derived U, Th, and Eu abundances. The results of this study open up a new avenue to reliably and homogeneously determine U abundance for a significantly larger number of RPE stars. This will, in turn, enable robust constraints on the nucleocosmochronometric ages of RPE stars, which can be applied to understand the chemical enrichment and evolution in the early universe, especially of r-process elements.

Course-prerequisite networks for analyzing and understanding academic curricula

Understanding a complex system of relationships between courses is of great importance for the university’s educational mission. This paper is dedicated to the study of course-prerequisite networks (CPNs), where nodes represent courses and directed links represent the formal prerequisite relationships between them. The main goal of CPNs is to model interactions between courses, represent the flow of knowledge in academic curricula, and serve as a key tool for visualizing, analyzing, and optimizing complex curricula. First, we consider several classical centrality measures, discuss their meaning in the context of CPNs, and use them for the identification of important courses. Next, we describe the hierarchical structure of a CPN using the topological stratification of the network. Finally, we perform the interdependence analysis, which allows to quantify the strength of knowledge flow between university divisions and helps to identify the most intradependent, influential, and interdisciplinary areas of study. We discuss how course-prerequisite networks can be used by students, faculty, and administrators for detecting important courses, improving existing and creating new courses, navigating complex curricula, allocating teaching resources, increasing interdisciplinary interactions between departments, revamping curricula, and enhancing the overall students’ learning experience. The proposed methodology can be used for the analysis of any CPN, and it is illustrated with a network of courses taught at the California Institute of Technology. The network data analyzed in this paper is publicly available in the GitHub repository.

Deep Learning Solution for Quantification of Fluorescence Particles on a Membrane.

The detection and quantification of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus particles in ambient waters using a membrane-based in-gel loop-mediated isothermal amplification (mgLAMP) method can play an important role in large-scale environmental surveillance for early warning of potential outbreaks. However, counting particles or cells in fluorescence microscopy is an expensive, time-consuming, and tedious task that only highly trained technicians and researchers can perform. Although such objects are generally easy to identify, manually annotating cells is occasionally prone to fatigue errors and arbitrariness due to the operator's interpretation of borderline cases. In this research, we proposed a method to detect and quantify multiscale and shape variant SARS-CoV-2 fluorescent cells generated using a portable (mgLAMP) system and captured using a smartphone camera. The proposed method is based on the YOLOv5 algorithm, which uses CSPnet as its backbone. CSPnet is a recently proposed convolutional neural network (CNN) that duplicates gradient information within the network using a combination of Dense nets and ResNet blocks, and bottleneck convolution layers to reduce computation while at the same time maintaining high accuracy. In addition, we apply the test time augmentation (TTA) algorithm in conjunction with YOLO's one-stage multihead detection heads to detect all cells of varying sizes and shapes. We evaluated the model using a private dataset provided by the Linde + Robinson Laboratory, California Institute of Technology, United States. The model achieved a mAP@0.5 score of 90.3 in the YOLOv5-s6.

A Time of Change

Fresh faces: Read Editor-in-Chief Claire M. Cobley's editorial to find out more about our new board members, the 2023 Ryoji Noyori ACES Award winner, and new ACES early career awards. The beginning of a new year is always a time of change, and this year even more so than most at ChemNanoMat. After eight years of service, two founding co-chairs of the Editorial Board, Susumu Kitagawa, Kyoto University, Japan, and Huisheng Peng, Fudan University, China, will be stepping down from their roles this year. They have given excellent guidance to the journal from before the first papers were even published and were central to the journal's successful launch in 2015. We would like to express our heartfelt appreciation to them both for their numerous contributions! Thankfully they are not going far, and will continue to stay connected to the journal through roles on the International Advisory Board. This year we also say goodbye to many of our other founding board members. Their connections to the scientific community have been crucial in putting ChemNanoMat on the map and helping us turn the idea of a nanoscience journal rooted in Asia into a reality. The team would like to say a big thank you to all of them for everything they have done for the journal over the years. Although we are sad to say goodbye to old friends, we are also excited to announce that many fresh faces are joining ChemNanoMat’s editorial and advisory boards in 2023. Pooi See Lee, Nanyang Technological University, Singapore, will be joining Hua Zhang, City University of Hong Kong, as a co-chair of the Editorial Board starting this year. She was among the first authors to publish in ChemNanoMat after the journal's 2015 launch, and we are delighted to have her bring her deep expertise in nanomaterials for energy and electronics applications to the co-chair role. You can find the biographies of Pooi See Lee and the rest of our new Editorial Board members at the end of this editorial. We look forward to working with all of them to further grow and develop ChemNanoMat in the years to come. I would also like to take a moment to share two important pieces of news from the Asian Chemical Editorial Society (ACES), the collaboration of 12 chemical societies across Asia and the Pacific that co-own ChemNanoMat. First of all, we are delighted to announce that Keiji Maruoka, Kyoto University, Japan, will be the recipient of the 2023 Ryoji Noyori ACES Award. This award is given every two years to a field-leading chemist in honor of Ryoji Noyori's key role in the founding of ACES and launch of the first ACES journal, Chemistry – An Asian Journal. We are currently planning an award symposium to celebrate Professor Maruoka's award at the IUPAC-CHAINS meeting in The Hague, The Netherlands, in August of this year. We hope you will join us there! Second, ACES has recently launched a new award series designed to highlight the achievements of early career scientists. These awards are given by individual society partners on behalf of ACES and include both an invitation to speak at a national meeting and an invitation to submit an article to one of the three ACES journals: Chemistry – An Asian Journal, the Asian Journal of Organic Chemistry, and ChemNanoMat. We look forward to publishing the work of many award winners in the future! It has been a pleasure to work with all of you over the past year. Here's to another great year and many more fruitful collaborations! Dr. Claire M. Cobley Editor-in-Chief ChemNanoMat Pooi See Lee received her Ph.D. degree from the National University of Singapore in 2002. She joined Chartered Semiconductor Manufacturing Ltd (now Globalfoundries) in the research and technology development department from 2002–2003. She is a recipient of the 2001 Norman Hackerman Young Author award presented by the Electrochemical Society, USA. In January 2004, she joined the School of Materials Science and Engineering, Nanyang Technological University as an Assistant Professor. She was promoted to tenured Associate Professor in 2009. In Sept 2015, she was promoted to Full Professor. Pooi See has authored and co-authored many publications in the field of nanomaterials for energy and electronics applications. She is interested in synthesizing innovative nanomaterials and harnessing their multi-functionality through understanding the structure-property characteristics. She has developed high energy capacitors, energy saving electrochromic coatings, novel transparent conductors, flexible and stretchable devices. She is keen on advancing the frontier of green nanotechnology and to translate research outcomes into real solutions. She was elected as the National Academy of Inventors (NAI) Fellow in 2020, the highest professional distinction accorded solely to academic inventors. Rona Chandrawati is a Scientia Associate Professor and NHMRC Emerging Leadership Fellow in the School of Chemical Engineering at The University of New South Wales (UNSW Sydney), Australia. She obtained her Ph.D. from The University of Melbourne in 2012 and was then a Marie Curie Fellow at Imperial College London before returning to Australia as a Lecturer (2015–2017), Scientia Senior Lecturer (2018–2020), and Scientia Associate Professor (2021-present). Her research group focuses on developing enzyme-like catalysts for drug delivery and designing polymer-based nanomaterials for sensors in food safety and health monitoring. Hyunjoo Lee received her B.S. and M.S. degree from Seoul National University, South Korea and Ph.D. degree from California Institute of Technology, USA. She is currently a full professor at KAIST. Her research interests include heterogeneous atomic catalysts with structure control and their applications for various gas-phase and electrochemical reactions. Yan Lu received her Ph.D. in macromolecular chemistry in 2005 at the Dresden University of Technology, Germany. After that, she worked first as postdoctoral researcher and then as a research scientist at the University of Bayreuth. In 2009, she joined the Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) as a group leader in Colloid Chemistry. Since 2017, she is a professor in the Institute of Chemistry at the University of Potsdam. She is now the head of the Department for Electrochemical Energy Storage at HZB. Her research focuses on design and synthesis of colloidal particles with tailored mesoscopic structures and their application as energy storage materials, catalysts and sensors. Pramod Pillai obtained his B.Sc. and M.Sc. from Mahatma Gandhi University in Kerala, India, followed by a Ph.D. in Chemistry from Cochin University of Science & Technology, in Kerala, India (work done at National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum, India). His Ph.D. research was on the optical properties of hybrid nanomaterials, in the group of Prof. K. George Thomas. After graduation, he worked as an Alexander von Humboldt postdoctoral fellow at Technische Universität Dortmund, Germany, in the group of Prof. Christof M. Niemeyer. This was followed by a second postdoctoral stay at Northwestern University in Evanston, U.S.A., in the group of Prof. Bartosz A. Grzybowski. During his postdoctoral research, he worked on interdisciplinary areas in nanoscience including nanoelectronics and nanobiotechnology. Currently, he is an Associate Professor in the Department of Chemistry at the Indian Institute of Science Education and Research (IISER) Pune, India. His research at IISER Pune is focused on the interplay of forces to control the light-matter interactions at the nanoscale. Some of the properties of interest include (photo)catalysis, trivial & non-trivial photophysics, and self-assembly in hybrid nanomaterials. Bing Xu, after receiving his B.S. and M.S. degrees from Nanjing University in 1987 and 1990, respectively, obtained his Ph.D. in 1996 from the University of Pennsylvania. Before starting his independent research at the Hong Kong University of Science and Technology (HKUST) in 2000, he was an NIH postdoctoral fellow at Harvard University. Dr. Xu was a tenured professor at HKUST until Jul. 2008 before he returned to Boston. He currently is a professor in the Department of Chemistry, Brandeis University. He has made pioneering contributions to metallogels, multifunctional magnetic nanoparticles, self-delivery drugs, supramolecular hydrogels, and enzyme-instructed self-assembly for in-situ anticancer nanomedicine. His current research focuses on the applications of enzymatic noncovalent synthesis in materials, biology, and medicine. Nobuhiro Yanai is an Associate Professor in the Department of Applied Chemistry at Kyushu University, Japan. He earned his Ph.D. from Kyoto University in 2011 under Prof. Susumu Kitagawa and Prof. Takashi Uemura on guest properties in metal-organic frameworks (MOFs)/porous coordination polymers (PCPs). He was a postdoctoral fellow with Prof. Steve Granick at the University of Illinois at Urbana-Champaign, experiencing colloid and soft matter sciences. He joined Kyushu University in 2012. He is currently leading a group that creates photo-functional materials, working on photon upconversion, dynamic nuclear polarization, and quantum materials. He received several awards including The Wiley Young Researcher Award, The APA (Asian and Oceanian Photochemistry Association) Prize for Young Scientists, and Award for Young Chemists, Chemical Society of Japan (CSJ). Qihua Yang received her Ph.D. degree in Inorganic Chemistry from Northeast Normal University. She did postdoctoral research in State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics (DICP, China), LCOMS-CNRS/CPE (France), and Toyota Central R&D Labs. Inc. (Japan). She joint DICP as a full professor in 2003 and moved to Zhejiang Normal University in 2022. Her research interests are mainly focused on the synthesis of hybrid porous materials for heterogeneous asymmetric catalysis and nano-catalysis. She is the author or co-author of more than 200 peer-reviewed scientific publications.

A Preview of JWST Metallicity Studies at Cosmic Noon: The First Detection of Auroral [O ii] Emission at High Redshift* *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 of the W. M. Keck Foundation.

We present ultradeep Keck/MOSFIRE rest-optical spectra of two star-forming galaxies at z = 2.18 in the COSMOS field with bright emission lines, representing more than 20 hr of total integration. The fidelity of these spectra enabled the detection of more than 20 unique emission lines for each galaxy, including the first detection of the auroral [O ii]λλ7322, 7332 lines at high redshift. We use these measurements to calculate the electron temperature in the low-ionization O+ zone of the ionized interstellar medium and derive abundance ratios of O/H, N/H, and N/O using the direct method. The N/O and α/Fe abundance patterns of these galaxies are consistent with rapid formation timescales and ongoing strong starbursts, in accord with their high specific star formation rates. These results demonstrate the feasibility of using auroral [O ii] measurements for accurate metallicity studies at high redshift in a higher-metallicity and lower-excitation regime previously unexplored with the direct method in distant galaxies. These results also highlight the difficulty in obtaining the measurements required for direct-method metallicities from the ground. We emphasize the advantages that the JWST/NIRSpec instrument will bring to high-redshift metallicity studies, where the combination of increased sensitivity and uninterrupted wavelength coverage will yield more than an order of magnitude increase in efficiency for multiplexed auroral-line surveys relative to current ground-based facilities. Consequently, the advent of JWST promises to be the beginning of a new era of precision chemical abundance studies of the early universe at a level of detail rivaling that of local galaxy studies.

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 of the W. M. Keck Foundation.

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 of the W. M. Keck Foundation.

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 Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. This work makes use of observations from the Las Cumbres Observatory global telescope network (LCOGT).

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.