Physical Sciences and Mathematics | Open Access Articles

Hypervolatiles In A Jupiter-Family Comet: Observations Of 45p/Honda–Mrkos–Pajdušáková Using Ishell At The Nasa-Irtf, Michael Disanti, Boncho Bonev, Neil Russo, Ronald Vervack, Erika Gibb, Nathan Roth, Adam Mckay, Hideyo Kawakita, Lori Feaga, Harold Weaver

Physics Faculty Works

We used the new high spectral resolution cross-dispersed facility spectrograph, iSHELL, at the NASA Infrared Telescope Facility on Maunakea, HI, to observe Jupiter-family comet (JFC) 45P/Honda–Mrkos–Pajdušáková. We report water production rates, as well as production rates and abundance ratios relative to H2O, for eight trace parent molecules (native ices), CO, CH4, H2CO, CH3OH, HCN, NH3, C2H2, and C2H6, on 2 days spanning UT 2017 January 6/7 and 7/8, shortly following perihelion. Trace species were measured simultaneously with H2O and/or OH prompt emission, a proxy for H2O production, thereby providing a robust and consistent means of establishing the native ice composition …

Go to article

Dynamic Technology Challenges Static Codes Of Ethics, Bo Brinkman, Catherine Flick, Don Gotterbarn, Keith Miller, Kate Vazansky, Marty J. Wolf

Computer Science Faculty Works

We describe the process of changing and the changes being suggested for the ACM Code of Ethics and Professional Conduct. In addition to addressing the technical and ethical basis for the proposed changes, we identify suggestions that commenters made in response to the first draft. We invite feedback on the proposed changes and on the suggestions that commenters made.

Go to article

First-Principles And Model Simulation Of All-Optical Spin Reversal, Thomas George, G.P. Zhang, Z. Babyak, Y. Xue, Y. Bai

Chemistry & Biochemistry Faculty Works

All-optical spin switching is a potential trailblazer for information storage and communication at an unprecedented fast rate free of magnetic fields. However, the current wisdom is largely based on semiempirical models of effective magnetic fields and heat pulses, so it is difficult to provide high-speed design protocols for actual devices. Here, we carry out a massively parallel first-principles and model calculation for 13 spin systems and magnetic layers, free of any effective field, to establish a simpler and alternative paradigm of laser-induced ultrafast spin reversal and to point out a path to a full-integrated photospintronic device. It is the interplay …

Go to article

Intramolecular Glycosylation, Alexei Demchenko, Xiao Jia

Chemistry & Biochemistry Faculty Works

Carbohydrate oligomers remain challenging targets for chemists due to the requirement for elaborate protecting and leaving group manipulations, functionalization, tedious purification, and sophisticated characterization. Achieving high stereocontrol in glycosylation reactions is arguably the major hurdle that chemists experience. This review article overviews methods for intramolecular glycosylation reactions wherein the facial stereoselectivity is achieved by tethering of the glycosyl donor and acceptor counterparts.

Go to article

Is Perpendicular Magnetic Anisotropy Essential To All-Optical Ultrafast Spin Reversal In Ferromagnets?, Thomas George, Y. Bai, G.P. Zhang

Chemistry & Biochemistry Faculty Works

All-optical spin reversal presents a new opportunity for spin manipulations, free of a magnetic field. Most of all-optical-spin-reversal ferromagnets are found to have a perpendicular magnetic anisotropy (PMA), but it has been unknown whether PMA is necessary for spin reversal. Here we theoretically investigate magnetic thin films with either PMA or in-plane magnetic anisotropy (IMA). Our results show that spin reversal in IMA systems is possible, but only with a longer laser pulse and within a narrow laser parameter region. Spin reversal does not show a strong helicity dependence where the left- and right-circularly polarized light lead to the identical …

Go to article

Biophysical And Computational Studies Of The Vcci:Vmip-Ii Complex, Anna Nguyen, Nai-Wei Kuo, Laura Showalter, Ricardo Ramos, Cynthia Dupureur, Michael Colvin, Patricia Liwang

Chemistry & Biochemistry Faculty Works

Certain viruses have the ability to subvert the mammalian immune response, including interference in the chemokine system. Poxviruses produce the chemokine binding protein vCCI (viral CC chemokine inhibitor; also called 35K), which tightly binds to CC chemokines. To facilitate the study of vCCI, we first provide a protocol to produce folded vCCI from Escherichia coli (E. coli.) It is shown here that vCCI binds with unusually high affinity to viral Macrophage Inflammatory Protein-II (vMIP-II), a chemokine analog produced by the virus, human herpesvirus 8 (HHV-8). Fluorescence anisotropy was used to investigate the vCCI:vMIP-II complex and shows that vCCI binds to …

Go to article

Beyond 3 Au From The Sun: The Hypervolatiles Ch4, C2h6, And Co In The Distant Comet C/2006 W3 (Christensen), Boncho Bonev, Geronimo Villanueva, Michael Disanti, Hermann Boehnhardt, Manuela Lippi, Erika Gibb, Lucas Paganini, Michael Mumma

Physics Faculty Works

Comet C/2006 W3 (Christensen) remained outside a heliocentric distance (R h) of 3.1 au throughout its apparition, but it presented an exceptional opportunity to directly sense a suite of molecules released from its nucleus. The Cryogenic Infrared Echelle Spectrograph at ESO-VLT detected infrared emissions from the three "hypervolatiles" (CO, CH4, and C2H6) that have the lowest sublimation temperatures among species that are commonly studied in comets by remote sensing. Even at R h = 3.25 au, the production rate of each molecule exceeded those measured for the same species in a number of other comets, although these comets were observed …

Go to article

Multiple Phase Transitions In An Agent-Based Evolutionary Model With Neutral Fitness, Sonya Bahar, Dawn King, Adam Scott

Physics Faculty Works

Null models are crucial for understanding evolutionary processes such as speciation and adaptive radiation. We analyse an agent-based null model, considering a case without selection—neutral evolution—in which organisms are defined only by phenotype. Universal dynamics has previously been demonstrated in a related model on a neutral fitness landscape, showing that this system belongs to the directed percolation (DP) universality class. The traditional null condition of neutral fitness (where fitness is defined as the number of offspring each organism produces) is extended here to include equal probability of death among organisms. We identify two types of phase transition: (i) a non-equilibrium …

Go to article

The Composition Of Comet C/2012 K1 (Panstarrs) And The Distribution Of Primary Volatile Abundances Among Comets, Nathan Roth, Erika Gibb, Boncho Bonev, Michael Disanti, Michael Mumma, Geronimo Villanueva, Lucas Paganini

Physics Faculty Works

On 2014 May 22 and 24 we characterized the volatile composition of the dynamically new Oort cloud comet C/2012 K1 (PanSTARRS) using the long-slit, high resolution (λ/Δλ ≈ 25,000) near-infrared echelle spectrograph (NIRSPEC) at the 10 m Keck II telescope on Maunakea, Hawaii. We detected fluorescent emission from six primary volatiles (H2O, HCN, CH4, C2H6, CH3OH, and CO). Upper limits were derived for C2H2, NH3, and H2CO. We report rotational temperatures, production rates, and mixing ratios (relative to water). Compared with median abundance ratios for primary volatiles in other sampled Oort cloud comets, trace gas abundance ratios in C/2012 K1 …

Go to article

Cyclipostins And Cyclophostin Analogs As Promising Compounds In The Fight Against Tuberculosis, Phuong Nguyen, Vincent Delorme, Anaïs Bénarouche, Benjamin Martin, Rishi Paudel, Giri Gnawali, Abdeldjalil Madani, Rémy Puppo, Valérie Landry, Laurent Kremer, Priscille Brodin, Christopher Spilling, Jean-François Cavalier, Stéphane Canaan

Chemistry & Biochemistry Faculty Works

A new class of Cyclophostin and Cyclipostins (CyC) analogs have been investigated against Mycobacterium tuberculosis H37Rv (M. tb) grown either in broth medium or inside macrophages. Our compounds displayed a diversity of action by acting either on extracellular M. tb bacterial growth only, or both intracellularly on infected macrophages as well as extracellularly on bacterial growth with very low toxicity towards host macrophages. Among the eight potential CyCs identified, CyC 17 exhibited the best extracellular antitubercular activity (MIC50 = 500 nM). This compound was selected and further used in a competitive labelling/enrichment assay against the activity-based probe Desthiobiotin-FP in order …

Go to article

Evolution Of Floral Zygomorphy In Androecium And Corolla In Solanaceae, Jingbo Zhang, Peter Stevens, Wenheng Zhang

Biology Department Faculty Works

In Solanaceae, a group dominated by actinomorphic‐flowered species, floral zygomorphy is frequently observed among the early‐branching clades. Morphological studies indicated that a zygomorphic androecium is much more common than a zygomorphic corolla in the family. Ontogenic studies suggested the evolution of floral zygomorphy in these two whorls is independent. Here, we have examined the evolution of floral symmetry in the androecium and corolla in Solanaceae. The character states of floral symmetry were assembled for androecium and corolla separately, and ancestral state reconstructions were carried out at both the genus and species levels for Solanaceae and its outgroups. Correlation tests were …

Go to article

Phylogenetic Patterns Of Rarity In A Regional Species Pool Of Tropical Woody Plants, M. Loza, Iván Jiménez, Peter Jørgensen, Gabriel Arellano, Manuel Macía, Vania Torrez, Robert Ricklefs

Biology Department Faculty Works

AimRarity, which is believed to influence extinction risk, can be defined in terms of local abundance, geographical range size and habitat breadth. Phylogenetic patterns in these attributes provide insight into the extent to which rarity and extinction risk are conserved during evolution and the potential for species‐level heritability. We evaluated phylogenetic signal (i.e., related species resembling each other more than species drawn at random) and evolutionary conservatism (similarity among related species exceeding that expected from a Brownian model of evolution) in three axes of rarity (local abundance, geographical range size and habitat breadth) among species in a regional pool of …

Go to article

Influence Of Macular Pigment Optical Density Spatial Distribution On Intraocular Scatter, Christopher Putnam, Pauline Bland, Carl Bassi

College of Optometry Faculty Works

No abstract provided.

Go to article

Physical Sciences and Mathematics Commons^™

Full-Text Articles in Physical Sciences and Mathematics

Hypervolatiles In A Jupiter-Family Comet: Observations Of 45p/Honda–Mrkos–Pajdušáková Using Ishell At The Nasa-Irtf, Michael Disanti, Boncho Bonev, Neil Russo, Ronald Vervack, Erika Gibb, Nathan Roth, Adam Mckay, Hideyo Kawakita, Lori Feaga, Harold Weaver

Physics Faculty Works

Dynamic Technology Challenges Static Codes Of Ethics, Bo Brinkman, Catherine Flick, Don Gotterbarn, Keith Miller, Kate Vazansky, Marty J. Wolf

Computer Science Faculty Works

First-Principles And Model Simulation Of All-Optical Spin Reversal, Thomas George, G.P. Zhang, Z. Babyak, Y. Xue, Y. Bai

Chemistry & Biochemistry Faculty Works

Intramolecular Glycosylation, Alexei Demchenko, Xiao Jia

Chemistry & Biochemistry Faculty Works

Is Perpendicular Magnetic Anisotropy Essential To All-Optical Ultrafast Spin Reversal In Ferromagnets?, Thomas George, Y. Bai, G.P. Zhang

Chemistry & Biochemistry Faculty Works

Biophysical And Computational Studies Of The Vcci:Vmip-Ii Complex, Anna Nguyen, Nai-Wei Kuo, Laura Showalter, Ricardo Ramos, Cynthia Dupureur, Michael Colvin, Patricia Liwang

Chemistry & Biochemistry Faculty Works

Beyond 3 Au From The Sun: The Hypervolatiles Ch4, C2h6, And Co In The Distant Comet C/2006 W3 (Christensen), Boncho Bonev, Geronimo Villanueva, Michael Disanti, Hermann Boehnhardt, Manuela Lippi, Erika Gibb, Lucas Paganini, Michael Mumma

Physics Faculty Works

Multiple Phase Transitions In An Agent-Based Evolutionary Model With Neutral Fitness, Sonya Bahar, Dawn King, Adam Scott

Physics Faculty Works

The Composition Of Comet C/2012 K1 (Panstarrs) And The Distribution Of Primary Volatile Abundances Among Comets, Nathan Roth, Erika Gibb, Boncho Bonev, Michael Disanti, Michael Mumma, Geronimo Villanueva, Lucas Paganini

Physics Faculty Works

Chemistry & Biochemistry Faculty Works

Evolution Of Floral Zygomorphy In Androecium And Corolla In Solanaceae, Jingbo Zhang, Peter Stevens, Wenheng Zhang

Biology Department Faculty Works

Phylogenetic Patterns Of Rarity In A Regional Species Pool Of Tropical Woody Plants, M. Loza, Iván Jiménez, Peter Jørgensen, Gabriel Arellano, Manuel Macía, Vania Torrez, Robert Ricklefs

Biology Department Faculty Works

Influence Of Macular Pigment Optical Density Spatial Distribution On Intraocular Scatter, Christopher Putnam, Pauline Bland, Carl Bassi

College of Optometry Faculty Works