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Recent Submissions

  • Col-OSSOS: The Colors of the Outer Solar System Origins Survey

    Schwamb, Megan E.; Fraser, Wesley C.; Bannister, Michele T.; Marsset, Michaël; Pike, Rosemary E.; Kavelaars, J. J.; Benecchi, Susan D.; Lehner, Matthew J.; Wang, Shiang-Yu; Thirouin, Audrey; et al. (IOP PUBLISHING LTD, 2019-07-11)
    The Colours of the Outer Solar System Origins Survey is acquiring near-simultaneous g, r, and J photometry of unprecedented precision with the Gemini North Telescope, targeting nearly 100 trans-Neptunian objects (TNOs) brighter than m(r) = 23.6 mag discovered in the Outer Solar System Origins Survey. Combining the optical and near-infrared photometry with the well-characterized detection efficiency of the Colours of the Outer Solar System Origins Survey target sample will provide the first flux-limited compositional dynamical map of the outer solar system. In this paper, we describe our observing strategy and detail the data reduction processes we employ, including techniques to mitigate the impact of rotational variability. We present optical and near-infrared colors for 35 TNOs. We find two taxonomic groups for the dynamically excited TNOs, the neutral and red classes, which divide at g - r similar or equal to 0.75. Based on simple albedo and orbital distribution assumptions, we find that the neutral class outnumbers the red class, with a ratio of 4:1 and potentially as high as 11:1. Including in our analysis constraints from the cold classical objects, which are known to exhibit unique albedos and r - z colors, we find that within our measurement uncertainty our observations are consistent with the primordial solar system protoplanetesimal disk being neutral class dominated, with two major compositional divisions in grJ color space.
  • The Extremely Luminous Quasar Survey in the Pan-STARRS 1 Footprint (PS-ELQS)

    Schindler, Jan-Torge; Fan, Xiaohui; Huang, Yun-Hsin; Yue, Minghao; Yang, Jinyi; Hall, Patrick B.; Wenzl, Lukas; Hughes, Allison; Litke, Katrina C.; Rees, Jon M.; et al. (IOP PUBLISHING LTD, 2019-07-01)
    We present the results of the Extremely Luminous Quasar Survey in the 3 pi survey of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS; PS1). This effort applies the successful quasar selection strategy of the Extremely Luminous Survey in the Sloan Digital Sky Survey footprint (similar to 12,000 deg(2)) to a much larger area (similar to 21,486 deg(2)). This spectroscopic survey targets the most luminous quasars (M-1450 <= -26.5; m(i) <= 18.5) at intermediate redshifts (z <= 2.8). Candidates are selected based on a near-infrared JKW2 color cut using WISE AllWISE and 2MASS photometry to mainly reject stellar contaminants. Photometric redshifts (z(reg)) and star-quasar classifications for each candidate are calculated from near-infrared and optical photometry using the supervised machine learning technique random forests. We select 806 quasar candidates at z(reg) >= 2.8 from a parent sample of 74,318 sources. After exclusion of known sources and rejection of candidates with unreliable photometry, we have taken optical identification spectra for 290 of our 334 good PS-ELQS candidates. We report the discovery of 190 new z >= 2.8 quasars and an additional 28 quasars at lower redshifts. A total of 44 good PS-ELQS candidates remain unobserved. Including all known quasars at z >= 2.8, our quasar selection method has a selection efficiency of at least 77%. At lower declinations, -30 <= decl. <= 0, we approximately treble the known population of extremely luminous quasars. We provide the PS-ELQS quasar catalog with a total of 592 luminous quasars (m(i) <= 18.5, z <= 2.8). This unique sample will not only be able to provide constraints on the volume density and quasar clustering of extremely luminous quasars, but also offers valuable targets for studies of the intergalactic medium.
  • An Extended Catalog of Galaxy–Galaxy Strong Gravitational Lenses Discovered in DES Using Convolutional Neural Networks

    Krause, E.; Univ Arizona, Steward Observ, Dept Astron (IOP PUBLISHING LTD, 2019-07-19)
    We search Dark Energy Survey (DES) Year 3 imaging for galaxy-galaxy strong gravitational lenses using convolutional neural networks, extending previous work with new training sets and covering a wider range of redshifts and colors. We train two neural networks using images of simulated lenses, then use them to score postage-stamp images of 7.9 million sources from DES chosen to have plausible lens colors based on simulations. We examine 1175 of the highest-scored candidates and identify 152 probable or definite lenses. Examining an additional 20,000 images with lower scores, we identify a further 247 probable or definite candidates. After including 86 candidates discovered in earlier searches using neural networks and 26 candidates discovered through visual inspection of blue-near-red objects in the DES catalog, we present a catalog of 511 lens candidates.
  • Follow-up of the Neutron Star Bearing Gravitational-wave Candidate Events S190425z and S190426c with MMT and SOAR

    Hosseinzadeh, G.; Cowperthwaite, P. S.; Gomez, S.; Villar, V. A.; Nicholl, M.; Margutti, R.; Berger, E.; Chornock, R.; Paterson, K.; Fong, W.; et al. (IOP PUBLISHING LTD, 2019-07-18)
    On 2019 April 25.346 and 26.640 UT the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo gravitational-wave (GW) observatory announced the detection of the first candidate events in Observing Run 3 that contained at least one neutron star (NS). S190425z is a likely binary neutron star (BNS) merger at d(L) = 156 +/- 41 Mpc, while S190426c is possibly the first NS-black hole (BH) merger ever detected, at d(L) = 377 +/- 100 Mpc, although with marginal statistical significance. Here we report our optical follow-up observations for both events using the MMT 6.5 m telescope, as well as our spectroscopic follow-up of candidate counterparts (which turned out to be unrelated) with the 4.1 m SOAR telescope. We compare to publicly reported searches, explore the overall areal coverage and depth, and evaluate those in relation to the optical/near-infrared (NIR) kilonova emission from the BNS merger GW170817, to theoretical kilonova models, and to short gamma-ray burst (SGRB) afterglows. We find that for a GW170817-like kilonova, the partial volume covered spans up to about 40% for S190425z and 60% for S190426c. For an on-axis jet typical of SGRBs, the search effective volume is larger, but such a configuration is expected in at most a few percent of mergers. We further find that wide-field gamma-ray and X-ray limits rule out luminous on-axis SGRBs, for a large fraction of the localization regions, although these searches are not sufficiently deep in the context of the gamma-ray emission from GW170817 or off-axis SGRB afterglows. The results indicate that some optical follow-up searches are sufficiently deep for counterpart identification to about 300 Mpc, but that localizations better than 1000 deg(2) are likely essential.
  • Independent modulation of individual genomic component transcription and a cis-acting element related to high transcriptional activity in a multipartite DNA virus

    Yu, Nai-Tong; Xie, Hui-Min; Zhang, Yu-Liang; Wang, Jian-Hua; Xiong, Zhongguo; Liu, Zhi-Xin; Univ Arizona, Inst BIO5; Univ Arizona, Sch Plant Sci (BMC, 2019-07-11)
    Background: The genome of Banana bunchy top virus (BBTV) consists of at least six circular, single-stranded DNA components of 1kb in length. Some BBTV isolates may also carry satellite DNA molecules that are not essential for BBTV infection. The relation between multipartite DNA virus replication and their transcriptional levels and the underlying mechanism remain unclear. Results: To understand the coordinated replication and transcription of the multiple genomic components, the absolute amounts of each BBTV DNA component were measured by real-time PCR (qPCR), and their transcriptional levels were determined by RNAseq and reverse transcription-qPCR (qRT-PCR). Significant differences were found in the absolute amounts of individual BBTV genomic components. Transcriptional levels of each BBTV genomic component obtained from the RNAseq data matched closely to those obtained from qRT-PCR, but did not correspond to the absolute amount of each DNA component. The ratio of transcript over DNA copies ranged from 46.21 to 1059.44%, which was possibly regulated by the promoter region in the intergenic region of each component. To further determine this speculation, the promoter region of the DNA-S, -M or -N was constructed to the upstream of green fluorescent protein (GFP) gene for transient expression by agrobacterium-mediated transformation method. The qRT-PCR showed the highest transcriptional activity was promoted by DNA-N promoter, about 386.58% activity comparing with CaMV 35S promoter. Confocal microscopy observation showed that the intensity of green fluorescence was corresponding to that of qRT-PCR. Conclusions: Our data clearly showed that BBTV was able to control the transcriptional level of each DNA component independently by through the promoter sequences in the intergenic region. Moreover, a cis-acting element from DNA-N component had a high transcriptional activity.
  • Analysis of networks of host proteins in the early time points following HIV transduction

    Csősz, Éva; Tóth, Ferenc; Mahdi, Mohamed; Tsaprailis, George; Emri, Miklós; Tőzsér, József; Univ Arizona, Arizona Res Labs (BMC, 2019-07-17)
    Background: Utilization of quantitative proteomics data on the network level is still a challenge in proteomics data analysis. Currently existing models use sophisticated, sometimes hard to implement analysis techniques. Our aim was to generate a relatively simple strategy for quantitative proteomics data analysis in order to utilize as much of the data generated in a proteomics experiment as possible. Results: In this study, we applied label-free proteomics, and generated a network model utilizing both qualitative, and quantitative data, in order to examine the early host response to Human Immunodeficiency Virus type 1 (HIV-1). A weighted network model was generated based on the amount of proteins measured by mass spectrometry, and analysis of weighted networks and functional sub-networks revealed upregulation of proteins involved in translation, transcription, and DNA condensation in the early phase of the viral life-cycle. Conclusion: A relatively simple strategy for network analysis was created and applied to examine the effect of HIV-1 on host cellular proteome. We believe that our model may prove beneficial in creating algorithms, allowing for both quantitative and qualitative studies of proteome change in various biological and pathological processes by quantitative mass spectrometry.
  • Substrate-source flexibility of an exponential-fed perfusion process to produce plasmid DNA for use as leishmaniasis vaccine

    García-Rendón, Aurora; García-Rendón, Angelica; Guzmán, Roberto; Tejeda-Mansir, Armando; Univ Arizona, Dept Chem & Environm Engn (TAYLOR & FRANCIS LTD, 2019-01-10)
    The use of plasmid DNA (pDNA) for human vaccines is a novel approach against leishmaniasis, a neglected tropical disease with severe clinical manifestations. The development of feasible bioprocesses to obtain such vaccines is a public-health priority. The aim of this work was to investigate the substrate-source flexibility of an exponential-fed perfusion (EFP) system to produce the plasmid pVAX1-NH36 for use as a leishmaniasis vaccine. Batch and EFP cultures were conducted using Escherichia coli DH5 alpha as a host and glucose or glycerol as a carbon source. The culture kinetics of the cell, substrate and plasmid concentrations were measured. Mathematical kinetics models were fitted to experimental data and used to describe the system comportment (r(2) > 0.95). Plasmid productivities of 13.3 mg/(L h) using glucose and 19.4 mg/(L h) using glycerol were obtained. These levels represent a 1-3-fold increase in performance index compared with previously reported cultures using E. coli DH5 alpha. The novel aspect of this work is the demonstration of the flexibility of EFP cultures for production of pDNA vaccines. Our data suggest that E. coli engineering to increase pDNA production using glucose can be circumvented with an EFP culture, reducing the host strain development costs. In addition, the greater productivity of EFP cultures entails a reduction in manufacturing costs.
  • A Novel, Highly Related Jumbo Family of Bacteriophages That Were Isolated Against Erwinia

    Sharma, Ruchira; Pielstick, Brittany A.; Bell, Kimberly A.; Nieman, Tanner B.; Stubbs, Olivia A.; Yeates, Edward L.; Baltrus, David A.; Grose, Julianne H.; Univ Arizona, Sch Plant Sci (Frontiers Media SA, 2019-07-23)
    Erwinia amylovora is a plant pathogen from the Erwiniaceae family and a causative agent of the devastating agricultural disease fire blight. Here we characterize eight lytic bacteriophages of E. amylovora that we isolated from the Wasatch front (Utah, United States) that are highly similar to vB_EamM_Ea35-70 which was isolated in Ontario, Canada. With the genome size ranging from 271 to 275 kb, this is a novel jumbo family of bacteriophages. These jumbo bacteriophages were further characterized through genomic and proteomic comparison, mass spectrometry, host range and burst size. Their proteomes are highly unstudied, with over 200 putative proteins with no known homologs. The production of 27 of these putative proteins was confirmed by mass spectrometry analysis. These bacteriophages appear to be most similar to bacteriophages that infect Pseudomonas and Ralstonia rather than Enterobacteriales bacteria by protein similarity, however, we were only able to detect infection of Erwinia and the closely related strains of Pantoea.
  • Prokaryotic Community Structure and Metabolisms in Shallow Subsurface of Atacama Desert Playas and Alluvial Fans After Heavy Rains: Repairing and Preparing for Next Dry Period

    Fernández-Martínez, Miguel Ángel; dos Santos Severino, Rita; Moreno-Paz, Mercedes; Gallardo-Carreño, Ignacio; Blanco, Yolanda; Warren-Rhodes, Kimberley; García-Villadangos, Miriam; Ruiz-Bermejo, Marta; Barberán, Albert; Wettergreen, David; et al. (Frontiers Media SA, 2019-07-24)
    The Atacama Desert, the oldest and driest desert on Earth, displays significant rains only once per decade. To investigate how microbial communities take advantage of these sporadic wet events, we carried out a geomicrobiological study a few days after a heavy rain event in 2015. Different physicochemical and microbial community analyses were conducted on samples collected from playas and an alluvial fan from surface, 10, 20, 50, and 80 cm depth. Gravimetric moisture content peaks were measured in 10 and 20 cm depth samples (from 1.65 to 4.1% w/w maximum values) while, in general, main anions such as chloride, nitrate, and sulfate concentrations increased with depth, with maximum values of 13-1,125; 168-10,109; and 9,904-30,952 ppm, respectively. Small organic anions such as formate and acetate had maximum concentrations from 2.61 to 3.44 ppm and 6.73 to 28.75 ppm, respectively. Microbial diversity inferred from DNA analysis showed Actinobacteria and Alphaproteobacteria as the most abundant and widespread bacterial taxa among the samples, followed by Chloroflexi and Firmicutes at specific sites. Archaea were mainly dominated by Nitrososphaerales, Methanobacteria, with the detection of other groups such as Halobacteria. Metaproteomics showed a high and even distribution of proteins involved in primary metabolic processes such as energy production and biosynthetic pathways, and a limited but remarkable presence of proteins related to resistance to environmental stressors such as radiation, oxidation, or desiccation. The results indicated that extra humidity in the system allows the microbial community to repair, and prepare for the upcoming hyperarid period. Additionally, it supplies biomarkers to the medium whose preservation potential could be high under strong desiccation conditions and relevant for planetary exploration.
  • Not so Dangerous After All? Venom Composition and Potency of the Pholcid (Daddy Long-Leg) Spider Physocyclus mexicanus

    Zobel-Thropp, Pamela A.; Mullins, Jennifer; Kristensen, Charles; Kronmiller, Brent A.; David, Cynthia L.; Breci, Linda A.; Binford, Greta J.; Univ Arizona, Arizona Prote Consortium (Frontiers Media SA, 2019-07-12)
    Pholcid spiders (Araneae: Pholcidae), officially "cellar spiders" but popularly known as "daddy long-legs," are renown for the potential of deadly toxic venom, even though venom composition and potency has never formally been studied. Here we detail the venom composition of male Physocyclus mexicanus using proteomic analyses and venom-gland transcriptomes ("venomics"). We also analyze the venom's potency on insects, and assemble available evidence regarding mammalian toxicity. The majority of the venom (51% of tryptic polypeptides and 62% of unique tryptic peptides) consists of proteins homologous to known venom toxins including enzymes (astacin metalloproteases, serine proteases and metalloendopeptidases, particularly neprilysins) and venom peptide neurotoxins. We identify 17 new groups of peptides (U1-17-PHTX) most of which are homologs of known venom peptides and are predicted to have an inhibitor cysteine knot fold; of these, 13 are confirmed in the proteome. Neprilysins (M13 peptidases), and astacins (M12 peptidases) are the most abundant venom proteins, respectively representing 15 and 11% of the individual proteins and 32 and 20% of the tryptic peptides detected in crude venom. Comparative evidence suggests that the neprilysin gene family is expressed in venoms across a range of spider taxa, but has undergone an expansion in the venoms of pholcids and may play a central functional role in these spiders. Bioassays of crude venoms on crickets resulted in an effective paralytic dose of 3.9 mu g/g, which is comparable to that of crude venoms of Plectreurys tristis and other Synspermiata taxa. However, crickets exhibit flaccid paralysis and regions of darkening that are not observed after P. tristis envenomation. Documented bites on humans make clear that while these spiders can bite, the typical result is a mild sting with no long-lasting effects. Together, the evidence we present indicates pholcid venoms are a source of interesting new peptides and proteins, and effects of bites on humans and other mammals are inconsequential.
  • Supplemental Data Files for article "Tracking the growth of the Himalayan fold-and-thrust belt from lower Miocene foreland basin strata: Dumri Formation, western Nepal"

    Stickroth, Simon; Carrapa, Barbara; DeCelles, Peter; Gehrels, George; Thomson, Stuart N.; University of Arizona Department of Geosciences (2019-08-16)
    New data from the lower Miocene Dumri Formation of western Nepal document exhumation of the Himalayan fold-thrust belt and provenance of the Neogene foreland basin system. We employ U-Pb zircon, Th-Pb monazite, 40Ar/39Ar white mica, and zircon fission-track (ZFT) chronometers to detrital minerals to constrain provenance, timing, and rate of exhumation of Himalayan source regions. Clusters of Proterozoic-early Paleozoic (900-400 Ma) Th-Pb monazite and 40Ar/39Ar white mica detrital ages provide evidence for erosion of a Greater Himalayan sequence protolith unaffected by high-grade Eohimalayan metamorphism. A small population of ~40 Ma cooling ages in detrital white mica grains shows exhumation of low-grade metamorphic Tethyan Himalayan sequence through the ~350°C closure temperature along the Tethyan Frontal thrust (proto-South Tibetan detachment) during the late Eocene. Dumri Formation detritus shows a ~12 Myr time difference between cooling of its source rocks through the ~350°C and ~240°C closure temperatures as recorded by ~40-38 Ma youngest peak cooling ages in 40Ar/39Ar detrital white mica and ~28-24 Ma youngest populations in detrital ZFT. Exhumation between ca. 40 Ma and 28 Ma is consistent with slip and exhumation along the Main Central thrust. Combined with similar data from northwestern India, our study suggests west-to-east spatially variable exhumation rates along strike of the Main Central thrust. Our data also show an increase in exhumation during middle Miocene-Pliocene time, which is consistent with growth of the Lesser Himalaya duplex.
  • SILVERRUSH. VII. Subaru/HSC Identifications of Protocluster Candidates at z ∼ 6–7: Implications for Cosmic Reionization

    Higuchi, Ryo; Ouchi, Masami; Ono, Yoshiaki; Shibuya, Takatoshi; Toshikawa, Jun; Harikane, Yuichi; Kojima, Takashi; Chiang, Yi-Kuan; Egami, Eiichi; Kashikawa, Nobunari; et al. (IOP PUBLISHING LTD, 2019-07-01)
    We report 14 and 26 protocluster candidates at z = 5.7 and 6.6 over 14 and 16 deg(2) areas, respectively, selected from 2230 (259) Ly alpha emitters (LAEs) photometrically (spectroscopically) identified using Subaru/Hyper Suprime-Cam (HSC) deep images (Keck, Subaru, and Magellan spectra, and literature data). Six out of the 40 protocluster candidates include one to 13 spectroscopically confirmed LAEs. We conduct Monte Carlo simulations to estimate how many protocluster candidates are found by chance for randomly distributed sources, and find that the effective number of protocluster candidates at z = 5.7 (6.6) is six (five). By comparing with the cosmological Ly alpha radiative transfer (RT) model reproducing the LAEs with reionization effects, we find that more than half of these protocluster candidates are progenitors of present-day clusters with mass of greater than or similar to 10(14)M(circle dot). We then investigate the correlation between the LAE overdensity delta and the Ly alpha rest-frame equivalent width EWLy alpha rest, because the cosmological Ly alpha RT model suggests that the slope of the EWLy alpha rest-delta relation steepens toward the epoch of cosmic reionization (EoR), due to the existence of ionized bubbles around galaxy overdensities easing the escape of Ly alpha emission from the partly neutral intergalactic medium. The available HSC data suggest that the slope of the EWLy alpha rest-delta correlation does not evolve from the post-reionization epoch, z = 5.7, to the EoR, z = 6.6, beyond the moderately large statistical errors. There is a possibility that we could detect the evolution of the EWLy alpha rest-delta relation from z = 5.7 to 7.3 using the upcoming HSC observations that will provide large samples of LAEs at z = 6.6-7.3.
  • Distance from Night Penning Areas as an Effective Proxy to Estimate Site Use Intensity by Grazing Sheep in the Alps

    Ravetto Enri, Simone; Gorlier, Alessandra; Nota, Ginevra; Pittarello, Marco; Lombardi, Giampiero; Lonati, Michele; Univ Arizona, Sch Nat Resources & Environm (MDPI AG, 2019-06-21)
    Livestock site use intensity can vary widely across a grazing area due to several factors such as topography and distance from sheds and water sources. However, an accurate approximation of animal site use should be assessed for each part of the grazing area to apply effective management strategies. In the Alps, shepherds manage sheep through lenient supervision during the day and confining the animals in temporary night penning areas (TNPA) at night. In our case study, we assessed sheep site use over the grazing area with global positioning system (GPS) collars and calculated the sums of inverse distances from all TNPA (unweighted and weighted on the number of penning nights) and from all water sources, as well as the slope, on 118 sample points. We assessed the relative importance of these variables in affecting site use intensity by animals using different sets of models. Both the unweighted and weighted distances from TNPA were found to be the most important factors. The best fitting model accounted for the weighted distance from TNPA and the distance from water, but the latter showed a lower relative importance. Our study suggests that using the distance from TNPA, preferably weighted on the number of penning nights, is an effective proxy to estimate the spatial variability of sheep stocking rate during grazing in the Alps.
  • Mercurial Metastatic Merkel Cell Carcinoma: A Case of Colonic Involvement

    Liu, Margaret C.; Ahmed, Shifat; Mehta, Shivang; Univ Arizona, Coll Med (Ovid Technologies (Wolters Kluwer Health), 2019-06)
    Merkel cell carcinoma (MCC) is a neuroendocrine skin cancer that typically presents as a painless erythematous nodule on body surfaces visible to the sun. Metastatic disease is typical to the lymph nodes, liver, and lungs. There are previous case reports of patients with metastases to the gastrointestinal tract including the stomach, small intestine, and pancreas. To our knowledge, there are only rare occurrences of metastases to the colon. We report a patient with a history of MCC treated with chemotherapy who presented with hematochezia and underwent a colonoscopy that showed a partially obstructing, edematous, friable 7-cmcircumferential mass in the transverse colon. Biopsy confirmed the diagnosis of MCC that metastasized to the transverse colon.
  • H-band discovery of additional second-generation stars in the Galactic bulge globular cluster NGC 6522 as observed by APOGEE and Gaia

    Cunha, K.; Univ Arizona, Steward Observ (EDP Sciences, 2019-07-22)
    We present an elemental abundance analysis of high-resolution spectra for five giant stars spatially located within the innermost regions of the bulge globular cluster NGC 6522 and derive Fe, Mg, Al, C, N, O, Si, and Ce abundances based on H-band spectra taken with the multi-object APOGEE-north spectrograph from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. Of the five cluster candidates, two previously unremarked stars are confirmed to have second-generation (SG) abundance patterns, with the basic pattern of depletion in C and Mg simultaneous with enrichment in N and Al as seen in other SG globular cluster populations at similar metallicity. In agreement with the most recent optical studies, the NGC 6522 stars analyzed exhibit (when available) only mild overabundances of the s-process element Ce, contradicting the idea that NGC 6522 stars are formed from gas enriched by spinstars and indicating that other stellar sources such as massive AGB stars could be the primary polluters of intra-cluster medium. The peculiar abundance signatures of SG stars have been observed in our data, confirming the presence of multiple generations of stars in NGC 6522.
  • A Chromaticity Analysis and PSF Subtraction Techniques for SCExAO/CHARIS Data

    Gerard, Benjamin L.; Marois, Christian; Currie, Thayne; Brandt, Timothy; Chilcote, Jeffrey K.; Draper, Zachary H.; Groff, Tyler; Guyon, Olivier; Hayashi, Masahiko; Jovanovic, Nemanja; et al. (IOP PUBLISHING LTD, 2019-07-01)
    We present an analysis of instrument performance using new observations taken with the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) instrument and the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system. In a correlation analysis of our data sets (which use the broadband mode covering the J band through the K band in a single spectrum), we find that chromaticity in the SCExAO/CHARIS system is generally worse than temporal stability. We also develop a point-spread function (PSF) subtraction pipeline optimized for the CHARIS broadband mode, including a forward modeling-based exoplanet algorithmic throughput correction scheme. We then present contrast curves using this newly developed pipeline. An analogous subtraction of the same data sets using only the H-band slices yields the same final contrasts as the full JHK sequences; this result is consistent with our chromaticity analysis, illustrating that PSF subtraction using spectral differential imaging (SDI) in this broadband mode is generally not more effective than SDI in the individual J, H, or K bands. In the future, the data processing framework and analysis developed in this paper will be important to consider for additional SCExAO/CHARIS broadband observations and other ExAO instruments which plan to implement a similar integral field spectrograph broadband mode.
  • Not a Simple Relationship between Neptune’s Migration Speed and Kuiper Belt Inclination Excitation

    Volk, Kathryn; Malhotra, Renu; Univ Arizona, Lunar & Planetary Lab (IOP PUBLISHING LTD, 2019-07-17)
    We present numerical simulations of giant planet migration in our solar system and examine how the speed of planetary migration affects inclinations in the resulting population of small bodies (test particles) scattered outward and subsequently captured into Neptune's 3:2 mean motion resonance (the Plutinos), as well as the hot classical Kuiper Belt population. We do not find a consistent relationship between the degree of test particle inclination excitation and e-folding planet migration timescales in the range 5-50 Myr. Our results present a counterexample to Nesvorny's finding that the Plutino and hot classical inclinations showed a marked increase with increasing e-folding timescales for Neptune's migration. We argue that these differing results are likely due to differing secular architectures of the giant planets during and after migration. Small changes in the planets' initial conditions and differences in the numerical implementation of planet migration can result in different amplitudes of the planets' inclination secular modes, and this can lead to different final inclination distributions for test particles in the simulations. We conclude that the observed large inclination dispersion of Kuiper Belt objects does not require Neptune's migration to be slow; planetary migration with e-folding timescales of 5, 10, 30, and 50 Myr can all yield inclination dispersions similar to the observed Plutino and hot classical populations, with no correlation between the degree of inclination excitation and migration speed.
  • Critical care nurses' clinical reasoning about physiologic monitor alarm customisation: An interpretive descriptive study

    Ruppel, Halley; Funk, Marjorie; Whittemore, Robin; Wung, Shu-Fen; Bonafide, Christopher P; Powell Kennedy, Holly; Univ Arizona, Coll Nursing (WILEY, 2019-08-01)
    Aims and objectives To explore clinical reasoning about alarm customisation among nurses in intensive care units. Background Critical care nurses are responsible for detecting and rapidly acting upon changes in patients' clinical condition. Nurses use medical devices including bedside physiologic monitors to assist them in their practice. Customising alarm settings on these devices can help nurses better monitor their patients and reduce the number of clinically irrelevant alarms. As a result, customisation may also help address the problem of alarm fatigue. However, little is known about nurses' clinical reasoning with respect to customising physiologic monitor alarm settings. Design This article is an in-depth report of the qualitative arm of a mixed methods study conducted using an interpretive descriptive methodological approach. Methods Twenty-seven nurses were purposively sampled from three intensive care units in an academic medical centre. Semi-structured interviews were conducted by telephone and were analysed using thematic analysis. Consolidated Criteria for Reporting Qualitative Research (COREQ) reporting guidelines were used. Results Four themes were identified from the interview data: unit alarm culture and context, nurse attributes, motivation to customise and customisation "know-how." A conceptual model demonstrating the relationship of these themes was developed to portray the factors that affect nurses' customisation of alarms. Conclusions In addition to drawing on clinical data, nurses customised physiologic monitor alarms based on their level of clinical expertise and comfort. Nurses were influenced by the alarm culture on their clinical unit and colleagues' and patients' responses to alarms, as well as their own technical understanding of the physiologic monitors. Relevance to clinical practice The results of this study can be used to design strategies to support the application of clinical reasoning to alarm management, which may contribute to more appropriate alarm customisation practices and improvements in safety.
  • A Survey for New Members of Taurus from Stellar to Planetary Masses

    Esplin, T. L.; Luhman, K. L.; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2019-07-10)
    We present a large sample of new members of the Taurus star-forming region that extend from stellar to planetary masses. To identify candidate members at substellar masses, we have used color-magnitude diagrams and proper motions measured with several wide-field optical and infrared (IR) surveys. At stellar masses, we have considered the candidate members that were found in a recent analysis of high-precision astrometry from the Gaia mission. Using new and archival spectra, we have measured spectral types and assessed membership for these 161 candidates, 79 of which are classified as new members. Our updated census of Taurus now contains 519 known members. According to Gaia data, this census should be nearly complete for spectral types earlier than M6-M7 at A(J) < 1. For a large field encompassing similar to 72% of the known members, the census should be complete for K < 15.7 at A(J) < 1.5, which corresponds to similar to 5-13. M-Jup for ages of 1-10. Myr based on theoretical evolutionary models. Our survey has doubled the number of known members at >= M9 and has uncovered the faintest known member in M-K, which should have a mass of similar to 3-10 M-Jup for ages of 1-10 Myr. We have used mid-IR photometry from the Spitzer Space Telescope and the Wide-field Infrared Survey Explorer to determine whether the new members exhibit excess emission that would indicate the presence of circumstellar disks. The updated disk fraction for Taurus is similar to 0.7 at <= M3.5 and similar to 0.4 at > M3.5.
  • On the Effect of Environment on Line Emission from the Circumgalactic Medium

    Zhang, Huanian; Zaritsky, Dennis; Behroozi, Peter; Werk, Jessica; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2019-07-22)
    We measure differences in the emission-line flux from the circumgalactic medium (CGM) of galaxies in different environments. Such differences could be a critical clue in explaining a range of galaxy properties that depend on environment. Using large samples of stacked archival spectra from the Sloan Digital Sky Survey, we find that the H alpha + [N II] emission-line flux from the CGM within 50 kpc of similar to L* galaxies is lower both for galaxies that lie within a projected distance of similar to 500 kpc from a massive (M-* > 10(11) M-circle dot) galaxy and for galaxies in richer/denser environments. The environmental differences are statistically significant even after we control for galaxy mass and morphology. We interpret these observations as a direct signature of environmentally caused strangulation. We present a simple, heuristic model for the effect of a massive parent galaxy. In this model, the CGM cool gas fraction within 50 kpc is significantly decreased for galaxies that lie within 700 kpc of a massive galaxy, with about 80% of the cool gas removed even when the galaxy is at a distance of 500 kpc from its massive parent. However, we discuss alternative physical causes for the observed behavior and discuss ways forward in addressing open questions.

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