Now showing items 13457-13476 of 13762

    • Visualizing the Topology and Data Traffic of Multi-Dimensional Torus Interconnect Networks

      Cheng, Shenghui; Zhong, Wen; Isaacs, Katherine E.; Mueller, Klaus; Univ Arizona, Comp Sci Dept (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018)
      Torus networks are an attractive topology in supercomputing, balancing the tradeoff between network diameter and hardware costs. The nodes in a torus network are connected in a k-dimensional wrap-around mesh where each node has 2 k neighbors. Effectively utilizing these networks can significantly decrease parallel communication overhead and in turn the time necessary to run large parallel scientific and data analysis applications. The potential gains are considerable-5-D torus networks are used in the majority of the top 10 machines in the November 2017 Graph 500 list. However, the multi-dimensionality of these networks makes it difficult for analysts to diagnose ill-formed communication patterns and poor network utilization since human spatial understanding is by and large limited to 3-Ds. We propose a method based on a space-filling Hilbert curve to linearize and embed the network into a ring structure, visualizing the data traffic as flowlines in the ring interior. We compare our method with traditional 2-D embedding techniques designed for high-dimensional data, such as MDS and RadViz, and show that they are inferior to ours in this application. As a demonstration of our approach, we visualize the datafiow of a massively parallel scientific code on a 5-D torus network.
    • Visually Lossless JPEG 2000 for Remote Image Browsing

      Oh, Han; Bilgin, Ali; Marcellin, Michael; Univ Arizona, Dept Biomed Engn; Univ Arizona, Dept Elect & Comp Engn (MDPI AG, 2016-07-15)
      Image sizes have increased exponentially in recent years. The resulting high-resolution images are often viewed via remote image browsing. Zooming and panning are desirable features in this context, which result in disparate spatial regions of an image being displayed at a variety of ( spatial) resolutions. When an image is displayed at a reduced resolution, the quantization step sizes needed for visually lossless quality generally increase. This paper investigates the quantization step sizes needed for visually lossless display as a function of resolution, and proposes a method that effectively incorporates the resulting ( multiple) quantization step sizes into a single JPEG 2000 codestream. This codestream is JPEG 2000 Part 1 compliant and allows for visually lossless decoding at all resolutions natively supported by the wavelet transform as well as arbitrary intermediate resolutions, using only a fraction of the full-resolution codestream. When images are browsed remotely using the JPEG 2000 Interactive Protocol ( JPIP), the required bandwidth is significantly reduced, as demonstrated by extensive experimental results.
    • Vitamin D deficiency is associated with chronic obstructive pulmonary disease and exacerbation of COPD

      Lokesh, Komarla Sundararaja; Chaya, Sindaghatta Krishnarao; Jayaraj, Biligere Siddaiah; Praveena, Attahalli Shivanarayanprasad; Krishna, Murali; Madhivanan, Purnima; Mahesh, Padukudru Anand; Department of Health Promotion Sciences, Mel & Enid Zuckerman College of Public Health, University of Arizona; Division of Infectious Diseases, College of Medicine, University of Arizona (Wiley-Blackwell, 2020-11-20)
      Introduction: Low Vitamin D levels have been associated with Chronic Obstructive Pulmonary Disease (COPD) and acute exacerbations. Objectives: There is a paucity of data on Vitamin D and COPD, its severity and exacerbations in populations that are exposed to sunlight regularly with high levels of physical activity most of their lives. Methods: Serum levels of 25-OH-Vitamin-D were assessed in 100 COPD subjects and 100 age- and gender-matched controls from the rural community-based MUDHRA cohort in South India. Levels of <20 ng/mL were defined as Vitamin D deficiency. Smoking habits, occupation, Charlson co-morbidity index, Standard of living index(SLI), body mass index(BMI), 6-minute walking distance were examined for associations with logistic regression between controls and COPD subjects. Unconditional logistic regression was used to examine the association with exacerbation of COPD. Results: Vitamin D deficiency was observed in 64.5% (95%CI 57.7–70.8) of the subjects in spite of regular exposure to sunlight. Subjects with COPD had higher risk of Vitamin D deficiency (Adjusted OR: 5.05; 95%CI 1.4–17.8) as compared to controls. Amongst subjects with COPD, Vitamin D deficient subjects were three times more likely to have exacerbations in the previous year (Adjusted OR:3.51; 95%CI 1.27–9.67) as compared to COPD subjects without Vitamin D deficiency. Levels of Vitamin D <20.81 ng/mL and <18.45 ng/mL had the highest levels of combined sensitivity and specificity for COPD and acute exacerbation of COPD (AECOPD) respectively. Conclusion: In a rural population exposed to sunlight many hours a day throughout their lives, low Vitamin D levels were associated with COPD and exacerbations of COPD. © 2020 John Wiley & Sons Ltd.
    • Vitamin D Receptor Mediates a Myriad of Biological Actions Dependent on Its 1,25-Dihydroxyvitamin D Ligand: Distinct Regulatory Themes Revealed by Induction of Klotho and Fibroblast Growth Factor-23

      Haussler, M.R.; Livingston, S.; Sabir, Z.L.; Haussler, C.A.; Jurutka, P.W.; Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix (Wiley, 2020)
      The hormonal vitamin D metabolite, 1,25-dihydroxyvitamin D [1,25(OH)2D], produced in kidney, acts in numerous end organs via the nuclear vitamin D receptor (VDR) to trigger molecular events that orchestrate bone mineral homeostasis. VDR is a ligand-controlled transcription factor that obligatorily heterodimerizes with retinoid X receptor (RXR) to target vitamin D responsive elements (VDREs) in the vicinity of vitamin D-regulated genes. Circulating 1,25(OH)2D concentrations are governed by PTH, an inducer of renal D-hormone biosynthesis catalyzed by CYP27B1 that functions as the key player in a calcemic endocrine circuit, and by fibroblast growth factor-23 (FGF23), a repressor of the CYP27B1 renal enzyme, creating a hypophosphatemic endocrine loop. 1,25(OH)2D/VDR–RXR acts in kidney to induce Klotho (a phosphaturic coreceptor for FGF23) to correct hyperphosphatemia, NPT2a/c to correct hypophosphatemia, and TRPV5 and CaBP28k to enhance calcium reabsorption. 1,25(OH)2D-liganded VDR–RXR functions in osteoblasts/osteocytes by augmenting RANK-ligand expression to paracrine signal osteoclastic bone resorption, while simultaneously inducing FGF23, SPP1, BGLP, LRP5, ANK1, ENPP1, and TNAP, and conversely repressing RUNX2 and PHEX expression, effecting localized control of mineralization to sculpt the skeleton. Herein, we document the history of 1,25(OH)2D/VDR and summarize recent advances in characterizing their physiology, biochemistry, and mechanism of action by highlighting two examples of 1,25(OH)2D/VDR molecular function. The first is VDR-mediated primary induction of Klotho mRNA by 1,25(OH)2D in kidney via a mechanism initiated by the docking of liganded VDR–RXR on a VDRE at −35 kb in the mouse Klotho gene. In contrast, the secondary induction of FGF23 by 1,25(OH)2D in bone is proposed to involve rapid nongenomic action of 1,25(OH)2D/VDR to acutely activate PI3K, in turn signaling the induction of MZF1, a transcription factor that, in cooperation with c-ets1-P, binds to an enhancer element centered at −263 bp in the promoter-proximal region of the mouse fgf23 gene. Chronically, 1,25(OH)2D-induced osteopontin apparently potentiates MZF1. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
    • The vitamin E analog, alpha-tocopheryloxyacetic acid enhances the anti-tumor activity of trastuzumab against HER2/neu-expressing breast cancer

      Hahn, Tobias; Bradley-Dunlop, Deborah; Hurley, Laurence; Von-Hoff, Daniel; Gately, Stephen; Mary, Disis; Lu, Hailing; Penichet, Manuel; Besselsen, David; Cole, Brook; et al. (BioMed Central, 2011)
      BACKGROUND:HER2/neu is an oncogene that facilitates neoplastic transformation due to its ability to transduce growth signals in a ligand-independent manner, is over-expressed in 20-30% of human breast cancers correlating with aggressive disease and has been successfully targeted with trastuzumab (Herceptin(R)). Because trastuzumab alone achieves only a 15-30% response rate, it is now commonly combined with conventional chemotherapeutic drugs. While the combination of trastuzumab plus chemotherapy has greatly improved response rates and increased survival, these conventional chemotherapy drugs are frequently associated with gastrointestinal and cardiac toxicity, bone marrow and immune suppression. These drawbacks necessitate the development of new, less toxic drugs that can be combined with trastuzumab. Recently, we reported that orally administered alpha-tocopheryloxyacetic acid (alpha-TEA), a novel ether derivative of alpha-tocopherol, dramatically suppressed primary tumor growth and reduced the incidence of lung metastases both in a transplanted and a spontaneous mouse model of breast cancer without discernable toxicity.METHODS:In this study we examined the effect of alpha-TEA plus HER2/neu-specific antibody treatment on HER2/neu-expressing breast cancer cells in vitro and in a HER2/neu positive human xenograft tumor model in vivo.RESULTS:We show in vitro that alpha-TEA plus anti-HER2/neu antibody has an increased cytotoxic effect against murine mammary tumor cells and human breast cancer cells and that the anti-tumor effect of alpha-TEA is independent of HER2/neu status. More importantly, in a human breast cancer xenograft model, the combination of alpha-TEA plus trastuzumab resulted in faster tumor regression and more tumor-free animals than trastuzumab alone.CONCLUSION:Due to the cancer cell selectivity of alpha-TEA, and because alpha-TEA kills both HER2/neu positive and HER2/neu negative breast cancer cells, it has the potential to be effective and less toxic than existing chemotherapeutic drugs when used in combination with HER2/neu antibody.
    • The Vivid Present: Visualization Abilities Are Associated with Steep Discounting of Future Rewards

      Parthasarathi, Trishala; McConnell, Mairead H.; Luery, Jeffrey; Kable, Joseph W.; Univ Arizona, Dept Psychol (FRONTIERS MEDIA SA, 2017-03-06)
      Humans and other animals discount the value of future rewards, a phenomenon known as delay discounting. Individuals vary widely in the extent to which they discount future rewards, and these tendencies have been associated with important life outcomes. Recent studies have demonstrated that imagining the future reduces subsequent discounting behavior, but no research to date has examined whether a similar principle applies at the trait level, and whether training visualization changes discounting. The current study examined if individual differences in visualization abilities are linked to individual differences in discounting and whether practicing visualization can change discounting behaviors in a lasting way. Participants (n = 48) completed the Vividness of Visual Imagery Questionnaire (VVIQ) and delay discounting task and then underwent a 4-week intervention consisting of visualization training (intervention) or relaxation training (control). Contrary to our hypotheses, participants who reported greater visualization abilities (lower scores) on the VVIQ were higher discounters. To further examine this relationship, an additional 106 participants completed the VVIQ and delay discounting task. In the total sample (n = 154), there was a significant negative correlation between VVIQ scores and discount rates, showing that individuals who are better visualizers are also higher discounters. Consistent with this relationship but again to our surprise, visualization training tended, albeit weakly, to increase discount rates, and those whose VVIQ decreased the most were those whose discount rates increased the most. These results suggest a novel association between visualization abilities and delay discounting.
    • VLA AND ALMA IMAGING OF INTENSE GALAXY-WIDE STAR FORMATION IN z ∼ 2 GALAXIES

      Rujopakarn, W.; Dunlop, J. S.; Rieke, George H.; Ivison, R. J.; Cibinel, A.; Nyland, K.; Jagannathan, P.; Silverman, J. D.; Alexander, David M.; Biggs, A. D.; et al. (IOP PUBLISHING LTD, 2016-12-01)
      We present; 0 4 resolution extinction-independent distributions of star formation and dust in 11 star-forming galaxies (SFGs) at z. =. 1.3-3.0. These galaxies are selected from sensitive blank-field surveys of the 2 x 2' Hubble Ultra-Deep Field at gimel = 5 cm and 1.3 mm using the Karl G. Jansky Very Large Array and Atacama Large Millimeter/submillimeter Array. They have star formation rates (SFRs), stellar masses, and dust properties representative of massive main-sequence SFGs at z similar to 2. Morphological classification performed on spatially resolved stellar mass maps indicates a mixture of disk and morphologically disturbed systems; half of the sample harbor X-ray active galactic nuclei (AGNs), thereby representing a diversity of z similar to 2 SFGs undergoing vigorous mass assembly. We find that their intense star formation most frequently occurs at the location of stellar-mass concentration and extends over an area comparable to their stellar-mass distribution, with a median diameter of 4.2 similar to 1.8 kpc. This provides direct evidence of galaxy-wide star formation in distant blank-field-selected main-sequence SFGs. The typical galactic-average SFR surface density is 2.5Me circle dot yr(-1) kpc(-2), sufficiently high to drive outflows. In X-ray-selected AGN where radio emission is enhanced over the level associated with star formation, the radio excess pinpoints the AGNs, which are found to be cospatial with star formation. The median extinctionindependent size of main-sequence SFGs is two times larger than those of bright submillimeter galaxies, whose SFRs are 3-8 times larger, providing a constraint on the characteristic SFR (similar to 300Me yr(-1)) above which a significant population of more compact SFGs appears to emerge.
    • The VLA Nascent Disk and Multiplicity Survey of Perseus Protostars (VANDAM). V. 18 Candidate Disks around Class 0 and I Protostars in the Perseus Molecular Cloud

      Segura-Cox, Dominique M.; Looney, Leslie W.; Tobin, John; Li, Zhi-Yun; Harris, Robert J.; Sadavoy, Sarah; Dunham, Michael M.; Chandler, Claire; Kratter, Kaitlin M.; Pérez, Laura; et al. (IOP PUBLISHING LTD, 2018-10-20)
      We present the full disk-fit results VANDAM survey of all Class 0 and I protostars in the Perseus molecular cloud. We have 18 new protostellar disk candidates around Class 0 and I sources, which are well described by a simple, parametrized disk model fit to the 8 mm VLA dust continuum observations. 33% of Class 0 protostars and just 11% of Class I protostars have candidate disks, while 78% of Class 0 and I protostars do not have signs of disks within our 12 au disk diameter resolution limit, indicating that at 8 mm most disks in the Class 0 and I phases are <10 au in radius. These small radii may be a result of surface brightness sensitivity limits. Modeled 8 mm radii are similar to the radii of known Class 0 disks with detected Keplerian rotation. Since our 8 mm data trace a population of larger dust grains that radially drift toward the protostar and are lower limits on true disk sizes, large disks at early times do not seem to be particularly rare. We find statistical evidence that Class 0 and I disks are likely drawn from the same distribution, meaning disk properties may be defined early in the Class 0 phase and do not undergo large changes through the Class I phase. By combining our candidate disk properties with previous polarization observations, we find a qualitative indication that misalignment between inferred envelope-scale magnetic fields and outflows may indicate disks on smaller scales in Class 0 sources.
    • VLA Observations of the Disk around the Young Brown Dwarf 2MASS J044427+2512

      Ricci, L.; Rome, H.; Pinilla, P.; Facchini, Stefano; Birnstiel, T.; Testi, L.; Univ Arizona, Dept Astron, Steward Observ (IOP PUBLISHING LTD, 2017-08-25)
      We present multi-wavelength radio observations obtained with the VLA of the protoplanetary disk surrounding the young brown dwarf 2MASS J04442713+2512164 (2M0444) in the Taurus star-forming region. 2M0444 is the brightest known brown dwarf disk at millimeter wavelengths, making this an ideal target to probe radio emission from a young brown dwarf. Thermal emission from dust in the disk is detected at 6.8 and 9.1 mm, whereas the 1.36 cm measured flux is dominated by ionized gas emission. We combine these data with previous observations at shorter sub-mm and mm wavelengths to test the predictions of dust evolution models in gas-rich disks after adapting their parameters to the case of 2M0444. These models show that the radial drift mechanism affecting solids in a gaseous environment has to be either completely made inefficient, or significantly slowed down by very strong gas pressure bumps in order to explain the presence of mm/cm-sized grains in the outer regions of the 2M0444 disk. We also discuss the possible mechanisms for the origin of the ionized gas emission detected at 1.36 cm. The inferred radio luminosity for this emission is in line with the relation between radio and bolometric luminosity valid for for more massive and luminous young stellar objects, and extrapolated down to the very low luminosity of the 2M0444 brown dwarf.
    • A VLA Study of High-redshift GRBs. I. Multiwavelength Observations and Modeling of GRB 140311A

      Laskar, Tanmoy; Berger, Edo; Chornock, Ryan; Margutti, Raffaella; Fong, Wen-Fai; Zauderer, B. Ashley; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2018-05)
      We present the first results from a recently concluded study of GRBs at z greater than or similar to 5 with the Karl G. Jansky Very Large Array (VLA). Spanning 1 to 85.5 GHz and 7 epochs from 1.5 to 82.3 days, our observations of GRB. 140311A are the most detailed joint radio and millimeter observations of a GRB afterglow at z greater than or similar to 5 to date. In conjunction with optical/near-IR and X-ray data, the observations can be understood in the framework of radiation from a single blast wave shock with energy E-K,E-iso approximate to 8.5 x 10(53) erg expanding into a constant density environment with density, n(0) approximate to 8 cm(-3). The X-ray and radio observations require a jet break at t(jet) approximate to 0.6 jet days, yielding an opening angle of 0(jet) approximate to 4 degrees and a beaming-corrected blast wave kinetic energy of E-K approximate to 2.2 x 10(50) erg. The results from our radio follow-up and multiwavelength modeling lend credence to the hypothesis that detected high-redshift GRBs may be more tightly beamed than events at lower redshift. We do not find compelling evidence for reverse shock emission, which may be related to fast cooling driven by the moderately high circumburst density.
    • A VLA Study of High-redshift GRBs. II. The Complex Radio Afterglow of GRB 140304A: Shell Collisions and Two Reverse Shocks

      Laskar, Tanmoy; Berger, Edo; Margutti, R.; Zauderer, B. Ashley; Williams, Peter K. G.; Fong, Wen-Fai; Sari, Re’em; Alexander, Kate D.; Kamble, Atish; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2018-06)
      We present detailed multifrequency, multiepoch radio observations of GRB. 140304A at z = 5.283 from 1 to 86 GHz and from 0.45 to 89 days. The radio and millimeter data exhibit unusual multiple spectral components, which cannot be simply explained by standard forward and reverse shock scenarios. Through detailed multiwavelength analysis spanning radio to X-rays, we constrain the forward shock parameters to E-k,E- iso approximate to 4.9 x 10(54) erg, A(*) approximate to 2.6 x 10(-2), epsilon(e) approximate to 2.5 x 10(-2), epsilon(B) approximate to 5.9 x 10(-2), p approximate to 2.6, and theta(jet) approximate to 1 degrees.1, yielding a beaming-corrected gamma-ray and kinetic energy, E gamma approximate to 2.3 x 10(49) erg and E-K approximate to 9.5 x 10(50) erg, respectively. We model the excess radio emission as due to a combination of a late-time reverse shock (RS) launched by a shell collision, which also produces a rebrightening in the X-rays at approximate to 0.26 days, and either a standard RS or diffractive interstellar scintillation (ISS). Under the standard RS interpretation, we invoke consistency arguments between the forward and reverse shocks to derive a deceleration time, t(dec) approximate to 100 s, the ejecta Lorentz factor, Gamma(t(dec)) approximate to 300, and a low RS magnetization, R-B approximate to 0.6. Our observations highlight both the power of radio observations in capturing RS emission and thus constraining the properties of GRB ejecta and central engines and the challenge presented by ISS in conclusively identifying RS emission in GRB radio afterglows.
    • A VLA SURVEY FOR FAINT COMPACT RADIO SOURCES IN THE ORION NEBULA CLUSTER

      Sheehan, Patrick D.; Eisner, Josh A.; Mann, Rita K.; Williams, Jonathan P.; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2016-11-04)
      We present Karl G. Jansky Very Large Array 1.3, 3.6, and 6 cm continuum maps of compact radio sources in the Orion Nebular Cluster (ONC). We mosaicked 34 arcmin(2) at 1.3 cm, 70 arcmin(2) at 3.6 cm and 109 arcmin(2) at 6 cm, containing 778 near-infrared detected young stellar objects and 190 Hubble Space Telescope-identified proplyds (with significant overlap between those characterizations). We detected radio emission from 175 compact radio sources in the ONC, including 26 sources that were detected for the first time at these wavelengths. For each detected source, we fitted a simple free-free and dust emission model to characterize the radio emission. We extrapolate the free-free emission spectrum model for each source to ALMA bands to illustrate how these measurements could be used to correctly measure protoplanetary disk dust masses from submillimeter flux measurements. Finally, we compare the fluxes measured in this survey with previously measured fluxes for our targets, as well as four separate epochs of 1.3 cm data, to search for and quantify the variability of our sources.
    • The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. I. Identifying and Characterizing the Protostellar Content of the OMC-2 FIR4 and OMC-2 FIR3 Regions

      Tobin, John J.; Megeath, S. Thomas; Hoff, Merel van’t; Díaz-Rodríguez, Ana Karla; Reynolds, Nickalas; Osorio, Mayra; Anglada, Guillem; Furlan, Elise; Karnath, Nicole; Offner, Stella S. R.; et al. (IOP PUBLISHING LTD, 2019-11-13)
      We present Atacama Large Millimeter/submillimeter Array (0.87 mm) and Very Large Array (9 mm) observations toward OMC-2 FIR4 and OMC-2 FIR3 within the Orion integral-shaped filament, thought to be two of the nearest regions of intermediate-mass star formation. We characterize the continuum sources within these regions on ~40 au (0farcs1) scales and associated molecular line emission at a factor of ~30 better resolution than previous observations at similar wavelengths. We identify six compact continuum sources within OMC-2 FIR4, four in OMC-2 FIR3, and one additional source just outside OMC-2 FIR4. This continuum emission is tracing the inner envelope and/or disk emission on less than 100 au scales. HOPS-108 is the only protostar in OMC-2 FIR4 that exhibits emission from high-excitation transitions of complex organic molecules (e.g., methanol and other lines) coincident with the continuum emission. HOPS-370 in OMC-2 FIR3, with L ~ 360 L ⊙, also exhibits emission from high-excitation methanol and other lines. The methanol emission toward these two protostars is indicative of temperatures high enough to thermally evaporate it from icy dust grains; overall, these protostars have characteristics similar to hot corinos. We do not identify a clear outflow from HOPS-108 in 12CO, but we find evidence of interaction between the outflow/jet from HOPS-370 and the OMC-2 FIR4 region. A multitude of observational constraints indicate that HOPS-108 is likely a low- to intermediate-mass protostar in its main mass accretion phase and is the most luminous protostar in OMC-2 FIR4. The high-resolution data presented here are essential for disentangling the embedded protostars from their surrounding dusty environments and characterizing them.
    • The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. II. A Statistical Characterization of Class 0 and Class I Protostellar Disks

      Tobin, John J.; Sheehan, Patrick D.; Megeath, S. Thomas; Díaz-Rodríguez, Ana Karla; Offner, Stella S. R.; Murillo, Nadia M.; van ’t Hoff, Merel L. R.; van Dishoeck, Ewine F.; Osorio, Mayra; Anglada, Guillem; et al. (IOP PUBLISHING LTD, 2020-02-20)
      We have conducted a survey of 328 protostars in the Orion molecular clouds with the Atacama Large Millimeter/submillimeter Array at 0.87 mm at a resolution of similar to 0.'' (40au), including observations with the Very Large Array at 9 mm toward 148 protostars at a resolution of similar to 0.'' 08 (32 au) This is the largest multiwavelength survey of protostars at this resolution by an order of magnitude. We use the dust continuum emission at 0.87 and 9 mm to measure the dust disk radii and masses toward the Class 0, Class I, and flat-spectrum protostars, characterizing the evolution of these disk properties in the protostellar phase. The mean dust disk radii for the Class 0, Class I, and flat-spectrum protostars are 44.9(-3.4)(+5.8), 37.0(-3.0)(+4.9), and 28.5(-2.3)(+3.7) au, respectively, and the mean protostellar dust disk masses are 25.9(-4.0)(+7.7), 14.9(-2.2)(+3.8), 1.6(-1.9)(+3.5) M-circle plus, respectively. The decrease in dust disk masses is expected from disk evolution and accretion, but the decrease in disk radii may point to the initial conditions of star formation not leading to the systematic growth of disk radii or that radial drift is keeping the dust disk sizes small. At least 146 protostellar disks (35% of 379 detected 0.87 mm continuum sources plus 42 nondetections) have disk radii greater than 50 au in our sample. These properties are not found to vary significantly between different regions within Orion. The protostellar dust disk mass distributions are systematically larger than those of Class II disks by a factor of >4, providing evidence that the cores of giant planets may need to at least begin their formation during the protostellar phase.
    • The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Perseus Protostars. VI. Characterizing the Formation Mechanism for Close Multiple Systems

      Tobin, John; Looney, Leslie W.; Li, Zhi-Yun; Sadavoy, Sarah I.; Dunham, Michael M.; Segura-Cox, Dominique; Kratter, Kaitlin M.; Chandler, Claire J.; Melis, Carl; Harris, Robert J.; et al. (IOP PUBLISHING LTD, 2018-11-01)
      We present Atacama Large Millimeter/submillimeter Array observations of multiple protostar systems in the Perseus molecular cloud, previously detected by the Karl G. Jansky Very Large Array. We observe 17 close (<600 au separation) multiple systems at 1.3 mm in continuum and five molecular lines (i.e., (CO)-C-12, (CO)-O-18, (CO)-C-13, H2CO, SO) to characterize the circum-multiple environments in which these systems are forming. We detect at least one component in the continuum for the 17 multiple systems. In three systems one companion is not detected, and for two systems the companions are unresolved at our observed resolution. We also detect circum-multiple dust emission toward eight out of nine Class 0 multiples. Circum-multiple dust emission is not detected toward any of the eight Class I multiples. Twelve systems are detected in the dense gas tracers toward their disks/inner envelopes. For these 12 systems, we use the dense gas observations to characterize their formation mechanism. The velocity gradients in the circum-multiple gas are clearly orthogonal to the outflow directions in eight out of the 12 systems, consistent with disk fragmentation. Moreover, only two systems with separations <200 au are inconsistent with disk fragmentation, in addition to the two widest systems (>500 au). Our results suggest that disk fragmentation via gravitational instability is an important formation mechanism for close multiple systems, but further statistics are needed to better determine the relative fraction formed via this method.
    • A VLBI receiving system for the South Pole Telescope

      Kim, Junhan; Marrone, Daniel P.; Beaudoin, Christopher; Carlstrom, John E.; Doeleman, Sheperd S.; Folkers, Thomas W.; Forbes, David; Greer, Christopher H.; Lauria, Eugene F.; Massingill, Kyle D.; et al. (SPIE-INT SOC OPTICAL ENGINEERING, 2018)
      The Event Horizon Telescope (EHT) is a very-long-baseline interferometry (VLBI) experiment that aims to observe supermassive black holes with an angular resolution that is comparable to the event horizon scale. The South Pole occupies an important position in the array, greatly increasing its north-south extent and therefore its resolution. The South Pole Telescope (SPT) is a 10-meter diameter, millimeter-wavelength telescope equipped for bolometric observations of the cosmic microwave background. To enable VLBI observations with the SPT we have constructed a coherent signal chain suitable for the South Pole environment. The dual-frequency receiver incorporates state-of-the-art SIS mixers and is installed in the SPT receiver cabin. The VLBI signal chain also includes a recording system and reference frequency generator tied to a hydrogen maser. Here we describe the SPT VLBI system design in detail and present both the lab measurements and on-sky results.
    • THE VLT LEGA-C SPECTROSCOPIC SURVEY: THE PHYSICS OF GALAXIES AT A LOOKBACK TIME OF 7 Gyr

      van der Wel, Arjen; Noeske, K.; Bezanson, Rachel; Pacifici, C.; Gallazzi, A.; Franx, Marijn; Muñoz-Mateos, J. C.; Bell, Eric F.; Brammer, Gabriel B.; Charlot, S.; et al. (IOP PUBLISHING LTD, 2016-04-22)
      The Large Early Galaxy Census (LEGA-C-16) is a Public Spectroscopic Survey of similar to 3200 K-band selected galaxies at redshifts z. =. 0.6 - 1.0 with stellar masses M-* > 10(10) M-circle dot, conducted with VIMOS on ESO's Very Large Telescope. The survey is embedded in the COSMOS field (R.A. = 10h00; decl. = +2 deg). The 20 hr long integrations produce high-signal-to-noise ratio continuum spectra that reveal ages, metallicities and velocity dispersions of the stellar populations. LEGA-C's unique combination of sample size and depth will enable us for the first time to map the stellar content at large lookback time, across galaxies of different types and star formation activity. Observations started in 2014 December and are planned to be completed by mid 2018, with early data releases of the spectra and value-added products. In this paper we present the science case, the observing strategy, an overview of the data reduction process and data products, and a first look at the relationship between galaxy structure and spectral properties, as it existed 7 Gyr ago.
    • VLTI images of circumbinary disks around evolved stars

      Kluska, J.; Claes, R.; Corporaal, A.; Van Winckel, H.; Alcolea, J.; Anugu, N.; Berger, J.-P.; Bollen, D.; Bujarrabal, V.; Izzard, R.; et al. (SPIE, 2020)
      The new generation of VLTI instruments (GRAVITY, MATISSE) aims to produce routinely interferometric images to uncover the morphological complexity of different objects at high angular resolution. Image reconstruction is, however, not a fully automated process. Here we focus on a specific science case, namely the complex circumbinary environments of a subset of evolved binaries, for which interferometric imaging provides the spatial resolution required to resolve the immediate circumbinary environment. Indeed, many binaries where the main star is in the post-asymptotic giant branch (post-AGB) phase are surrounded by circumbinary disks. Those disks were first inferred from the infrared excess produced by dust. Snapshot interferometric observations in the infrared confirmed disk-like morphology and revealed high spatial complexity of the emission that the use of geometrical models could not recover without being strongly biased. Arguably, the most convincing proof of the disk-like shape of the circumbinary environment came from the first interferometric image of such a system (IRAS08544-4431) using the PIONIER instrument at the VLTI. This image was obtained using the SPARCO image reconstruction approach that enables to subtract a model of a component of the image and reconstruct an image of its environment only. In the case of IRAS08544-4431, the model involved a binary and the image of the remaining signal revealed several unexpected features. Then, a second image revealed a different but also complex circumstellar morphology around HD101584 that was well studied by ALMA. To exploit the VLTI imaging capability to understand these targets, we started a large programme at the VLTI to image post-AGB binary systems using both PIONIER and GRAVITY instruments. © 2020 SPIE. All rights reserved.
    • Voicing the supply chain

      Cotter, W.M.; University of Arizona (University of Chicago Press, 2021)
      The specialty coffee industry emphasizes the importance of personal relationships that span disparate levels of the supply chain and production models that focus on the wellbeing of coffee producers. This emphasis presents specialty coffee as a socially progressive form of consumption that is often represented as superior to mass-produced coffee. Discourses that emphasize relationships between baristas and professionals at other levels of the supply chain serve as a tool in marketing specialty coffee, with baristas serving as an interface between consumers and other levels of the supply chain. The somewhat recent elevation of baristas to professional status is due, in part, to the growth of barista competitions. This article takes barista competitions as a context for analysis, highlighting how baristas incorporate voices from across the supply chain into their competition performances. I argue that in voicing individuals from across the supply chain, baristas draw on the expertise and authority represented by coffee farmers and roasters to support the development of their own authentic professional persona. This article also shows that, by voicing the supply chain, baristas respond to consumer desires for more ethical forms of consumption through these narratives, providing the moral and emotional experience of coffee that consumers crave. © 2021 by Semiosis Research Center at Hankuk University of Foreign Studies.
    • Volatility in daily relationship quality

      Cooper, Ashley N.; Totenhagen, Casey J.; McDaniel, Brandon T.; Curran, Melissa A.; Univ Arizona (SAGE PUBLICATIONS LTD, 2018-03)
      Previous research on attachment orientations has focused on how attachment is associated with levels of relationship quality; however, the nature of associations with variability over time (volatility) on relationship quality remains unclear. Couples who are higher in volatility have poorer relationship outcomes, thus it is important to understand factors that influence volatility. We used 7-day daily diaries with both members of 157 heterosexual couples to analyze associations between actor and partner reports of attachment anxiety and avoidance and gender in associations with both general levels of relationship quality and volatility in daily relationship quality. Overall, we found that regardless of gender, attachment avoidance was linked with decreased levels of relationship quality for both actors and partners. Gender differences in volatility of daily relationship quality emerged such that women's attachment influenced both their own and their male partner's volatility. Women's attachment anxiety was positively associated with volatility for both their own and their partner's relationship quality. Women's attachment avoidance was also negatively associated with volatility in their partner's relationship quality. We discuss how attachment avoidance is a greater predictor for average levels of daily relationship quality, whereas attachment anxiety drives volatility in daily feelings about the relationship. Further, conflict is an important factor to consider in these links between attachment anxiety and volatility in relationship quality; on days when individuals reported greater conflict than usual, they reported lower relationship quality, and this association was stronger for those whose partners were high in attachment anxiety. We explore implications for research and practice.