Now showing items 1-20 of 70722

    • The Discovery of Extended Thermal X‐Ray Emission from PKS 2152−699: Evidence for a “Jet‐Cloud” Interaction

      Ly, Chun; De Young, David S.; Bechtold, Jill; Univ Arizona, Steward Observatory (IOP Publishing, 2005-01-10)
      A Chandra ACIS-S observation of PKS 2152-699 reveals thermal emission from a diffuse region around the core and a hotspot located 10" northeast from the core. This is the first detection of thermal X-ray radiation on kiloparsec scales from an extragalactic radio source. Two other hotspots located 47" north-northeast and 26" southwest from the core were also detected. Using a Raymond-Smith model, the first hotspot can be characterized with a thermal plasma temperature of 2.6×10^6 K and an electron number density of 0.17 cm^-3. These values correspond to a cooling time of ~1.6×10^7 yr. In addition, an emission line from the hotspot, possibly Fe XXV, was detected at rest wavelength 10.04 Å. The thermal X-ray emission from the first hotspot is offset from the radio emission but is coincident with optical filaments detected with broadband filters of Hubble Space Telescope WFPC2. The best explanation for the X-ray, radio, and optical emission is that of a ``jet-cloud'' interaction. The diffuse emission around the nucleus of PKS 2152-699 can be modeled as a thermal plasma with a temperature of 1.2×10^7 K and a luminosity of 1.8×10^41 ergs/s. This emission appears to be asymmetric, with a small extension toward hotspot A, similar to a jet. An optical hotspot (extended emission-line region) is seen less than 1" away from this extension in the direction of the core. This indicates that the extension may be caused by the jet interacting with an inner interstellar medium cloud, or that it is due to entrainment of hot gas. Future observations are discussed.
    • Exploring multimedia, mobile learning, and place-based learning in linguacultural education

      Han, Yiting; Univ Arizona (UNIV HAWAII, NATL FOREIGN LANGUAGE RESOURCE CENTER, 2019-10)
      Culture, as the fifth language skill, enables learners to develop into multilingually and multiculturally aware global citizens. The traditional Chinese architecture is as old as Chinese civilization. The wisdom, stories, and cultural elements behind traditional Chinese construction is a valued aspect of Chinese culture. This article introduces a LiveCode based mobile application featuring a virtual tour of two traditional Chinese architecture sites Nan Yuan and Humble Administrator's Garden. The application is designed by the author for advanced Chinese learners for an immersive linguacultural learning experience. Built-in tools, rollover hints, authentic multimedia resources and useful links of the application effectively integrate culture with language learning. Pedagogical applications, pilot outcomes, implications, and future directions of mobile learning and place-based learning in Chinese linguacultural education are also addressed in this paper.
    • PaCTS 1.0: A Crowdsourced Reporting Standard for Paleoclimate Data

      Thirumalai, K.; Univ Arizona, Dept Geosci (AMER GEOPHYSICAL UNION, 2019)
      The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community-sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of maximizing the reuse value of paleoclimate data sets, particularly for synthesis work and comparison to climate model simulations. Initiated by the LinkedEarth project, the process to elicit a reporting standard involved an international workshop in 2016, various forms of digital community engagement over the next few years, and grassroots working groups. Participants in this process identified important properties across paleoclimate archives, in addition to the reporting of uncertainties and chronologies; they also identified archive-specific properties and distinguished reporting standards for new versus legacy data sets. This work shows that at least 135 respondents overwhelmingly support a drastic increase in the amount of metadata accompanying paleoclimate data sets. Since such goals are at odds with present practices, we discuss a transparent path toward implementing or revising these recommendations in the near future, using both bottom-up and top-down approaches.
    • Identification of Actionable Fusions as an Anti-EGFR Resistance Mechanism Using a Circulating Tumor DNA Assay

      Clifton, Katherine; Rich, Thereasa A.; Parseghian, Christine; Raymond, Victoria M.; Dasari, Arvind; Pereira, Allan Andresson Lima; Willis, Jason; Loree, Jonathan M.; Bauer, Todd M.; Chae, Young Kwang; et al. (AMER SOC CLINICAL ONCOLOGY, 2019-10-03)
      PURPOSE: Gene fusions are established oncogenic drivers and emerging therapeutic targets in advanced colorectal cancer. This study aimed to detail the frequencies and clinicopathological features of gene fusions in colorectal cancer using a circulating tumor DNA assay. METHODS: Circulating tumor DNA samples in patients with advanced colorectal cancer were analyzed at 4,581 unique time points using a validated plasma-based multigene assay that includes assessment of fusions in FGFR2, FGFR3, RET, ALK, NTRK1, and ROS1. Associations between fusions and clinicopathological features were measured using Fisher's exact test. Relative frequencies of genomic alterations were compared between fusion-present and fusion-absent cases using an unpaired t test. RESULTS: Forty-four unique fusions were identified in 40 (1.1%) of the 3,808 patients with circulating tumor DNA detected: RET(n = 6; 36% of all fusions detected), FGFR3 (n = 2; 27%), ALK(n = 10, 23%), NTRK1 (n = 3; 7%), ROS1 (n = 2; 5%), and FGFR2 (n = 1; 2%). Relative to nonfusion variants detected, fusions were more likely to be subclonal (odds ratio, 8.2; 95% CI, 2.94 to 23.00; P < .001). Mutations associated with a previously reported anti-epidermal growth factor receptor (anti-EGFR) therapy resistance signature (subclonal RAS and EGFR mutations) were found with fusions in FGFR3 (10 of 12 patients), RET(nine of 16 patients), and ALK(seven of 10 patients). For the 27 patients with available clinical histories, 21 (78%) had EGFR monoclonal antibody treatment before fusion detection. CONCLUSION: Diverse and potentially actionable fusions can be detected using a circulating tumor DNA assay in patients with advanced colorectal cancer. Distribution of coexisting subclonal mutations in EGFR, KRAS, and NRAS in a subset of the patients with fusion-present colorectal cancer suggests that these fusions may arise as a novel mechanism of resistance to anti-EGFR therapies in patients with metastatic colorectal cancer.
    • Khayyam, Omar: v. English Translations of the “Rubaiyat”

      O'Malley, Austin; Univ Arizona, Sch Middle Eastern & North African Studies (Brill, 2019)
    • Excited-state effects in nucleon structure on the lattice using hybrid interpolators

      Green, Jeremy R.; Engelhardt, Michael; Hasan, Nesreen; Krieg, Stefan; Meinel, Stefan; Negele, John W.; Pochinsky, Andrew V.; Syritsyn, Sergey N.; Univ Arizona, Dept Phys (AMER PHYSICAL SOC, 2019-10-24)
      It would be very useful to find a way of reducing excited-state effects in lattice QCD calculations of nucleon structure that has a low computational cost. We explore the use of hybrid interpolators, which contain a nontrivial gluonic excitation, in a variational basis together with the standard interpolator with tuned smearing width. Using the clover discretization of the field strength tensor, a calculation using a fixed linear combination of standard and hybrid interpolators can be done using the same number of quark propagators as a standard calculation, making this a cost-effective option. We find that such an interpolator, optimized by solving a generalized eigenvalue problem, reduces excited-state contributions in two-point correlators. However, the effect in three-point correlators, which are needed for computing nucleon matrix elements, is mixed: for some matrix elements such as the tensor charge, excited-state effects are suppressed, whereas for others such as the axial charge, they are enhanced. The results illustrate that the variational method is not guaranteed to reduce the net contribution from excited states except in its asymptotic regime, and suggest that it may be important to use a large basis of interpolators capable of isolating all of the relevant low-lying states.
    • Islands of ice on Mars and Pluto

      Sori, Michael M.; Bapst, Jonathan; Becerra, Patricio; Byrne, Shane; Univ Arizona, Lunar & Planetary Lab (AMER GEOPHYSICAL UNION, 2019)
      Ice sheets, such as the polar layered deposits (PLDs) of Mars, are of great interest as records of past climate. Smaller outlier ice deposits near the north and south PLDs are likely more sensitive to climate changes and thus may hold information about more recent climate history. However, the southern outlier deposits have largely remained unmapped and unanalyzed. Here, we identify 31 deposits near, but separated from, Mars's south PLDs, all of which are located within impact craters >15 km in diameter. On the basis of morphology, radar analysis, physical similarity to portions of the PLD margin, and overall similarity to previously described deposits in Mars's north polar region, we conclude that these deposits are primarily composed of water ice. An additional 66 craters contain smaller depositional features, some of which may be remnant ice deposits. The 31 outlier ice deposits represent a previously unquantified inventory of water on Mars, with a total volume between 15,000 and 38,000 km(3). In addition, we identify five analogous outlier nitrogen ice deposits located within impact craters near Sputnik Planitia, the large nitrogen ice sheet on Pluto. Although important differences exist between Mars and Pluto, broad physical similarities between the two cases suggest that the topography and microclimates of impact craters cause them to be favorable locations for volatile accumulation and/or retention throughout the Solar System.
    • Thermal broadening of bottomonia: Lattice nonrelativistic QCD with extended operators

      Larsen, Rasmus; Meinel, Stefan; Mukherjee, Swagato; Petreczky, Peter; Univ Arizona, Dept Phys (AMER PHYSICAL SOC, 2019-10-21)
      We present lattice nonrelativistic QCD calculations of bottomonium correlation functions at temperatures T similar or equal to 150-350 MeV. The correlation functions were computed using extended bottomonium operators and on background gauge-field configurations for 2 + 1-flavor QCD having physical kaon and nearly physical pion masses. We analyzed these correlation functions based on simple theoretically motivated parametrizations of the corresponding spectral functions. The results of our analyses are compatible with significant in-medium thermal broadening of the ground state S- and P-wave bottomonia.
    • Selective Wander Join: Fast Progressive Visualizations for Data Joins

      Procopio, Marianne; Scheidegger, Carlos; Wu, Eugene; Chang, Remco; Univ Arizona, Dept Comp Sci (MDPI, 2019-03)
      Progressive visualization offers a great deal of promise for big data visualization; however, current progressive visualization systems do not allow for continuous interaction. What if users want to see more confident results on a subset of the visualization? This can happen when users are in exploratory analysis mode but want to ask some directed questions of the data as well. In a progressive visualization system, the online aggregation algorithm determines the database sampling rate and resulting convergence rate, not the user. In this paper, we extend a recent method in online aggregation, called Wander Join, that is optimized for queries that join tables, one of the most computationally expensive operations. This extension leverages importance sampling to enable user-driven sampling when data joins are in the query. We applied user interaction techniques that allow the user to view and adjust the convergence rate, providing more transparency and control over the online aggregation process. By leveraging importance sampling, our extension of Wander Join also allows for stratified sampling of groups when there is data distribution skew. We also improve the convergence rate of filtering queries, but with additional overhead costs not needed in the original Wander Join algorithm.
    • Property’s Relation to Human Rights

      Rose, Carol M.; Univ Arizona, Law Coll (ROUTLEDGE, TAYLOR & FRANCIS GROUP, 2019)
      How does property relate to human rights? Is property itself a human right, or contrariwise, an impediment to other human rights? or is the relationship something else? This chapter explores three areas in which property has raised controversies in modern human rights discussions: first, property’s connection to traditional groups’ claims to protect cultural identity; second, property’s role respecting human rights claims to social and economic rights; and finally, the role of property protection in deflecting other human rights abuses. This paper argues that in all these instances, property’s relation to human rights is best treated pragmatically, framing particular issues by inquiring about the ways in which property might or might not support other human rights claims—an inquiry that sometimes leads to unexpected results.
    • Presenteeism: Nurse perceptions and consequences

      Rainbow, Jessica G; Univ Arizona, Coll Nursing (WILEY, 2019-10-01)
      Aims To describe factors leading to and consequences of nurse presenteeism. Background Presenteeism is more prevalent among nurses than other occupational groups. Existing literatures focuses on prevalence and consequences of presenteeism for patients, health care organizations, and nurses. However, we lack understanding of nurse perceptions of factors leading to and consequences of presenteeism. Methods A total of 295 free responses to a cross-sectional survey were analysed using conventional content analysis. Results Nurses consider multiple factors in deciding how to respond when presentee. These include illness, staffing, availability of leave time, patients, financial constraints and guilt. Consequences of presenteeism identified were decreased mental acuity and attitude leading to lessened communication both in-person and in documentation, transmission of illness, and decline in unit culture, patient care, and nurse health and well-being. Conclusions Multiple factors lead to nurse presenteeism and there are negative consequences to nurses' health, work environment and patient care outcomes. Implications for Nursing Management This study leads to key discoveries to the reasons for and consequences of nurse presenteeism. Many of the factors leading to presenteeism can be addressed through culture and policy changes within organizations. The consequences to patient care outcomes and the work environment emphasize the importance of addressing presenteeism.
    • A record of flooding on the White River, Arkansas derived from tree-ring anatomical variability and vessel width

      Meko, Matthew D.; Therrell, Matthew D.; Univ Arizona, Lab Tree Ring Res (TAYLOR & FRANCIS LTD, 2019-10-13)
      Tree rings preserve important records of past flooding. We present the results of an examination of inter-annual tree-ring anatomical variability and vessel width in overcup oak (Quercus lyrata) and river flooding at a bottomland hardwood forest site near the confluence of the White and Mississippi Rivers. We developed two flood chronologies based on (1) visual identification of ?flood-ring? anatomical anomalies and (2) a simple method for quantitative measurements of earlywood vessel width (VW). Using visual flood rings, we have developed a response index (RI) chronology of floods from 1780?2013 and, using the VW measurements, we have developed a quantitative reconstruction of spring river levels from 1800?2013. Both the RI and VW chronologies are strongly related to spring river flooding and indicate that major floods such as those in 1805, 1826, 1844, 1852, 1858, occurred in the period prior to the systematic collection of stage data, and that the frequency of extreme events has greatly varied over the past two centuries. These chronologies provide important new information about Lower Mississippi River flooding in past centuries, and our simple method of measuring VW is a potentially useful new approach to the development of tree-ring records of flooding.
    • Assessment of YAP gene polymorphisms and arsenic interaction in Mexican women with breast cancer

      Michel-Ramirez, Gladis; Recio-Vega, Rogelio; Lantz, R Clark; Gandolfi, A Jay; Olivas-Calderon, Edgar; Chau, Binh T; Amistadi, Mary Kay; Univ Arizona, Dept Cellular & Mol Med; Univ Arizona, Southwest Environm Hlth Sci Ctr; Univ Arizona, Dept Pharmacol & Toxicol; et al. (WILEY, 2019-10-21)
      The identification of gene-environment interactions related to breast cancer reveals the biological and molecular mechanisms underlying the disease and allows the distinction of women at high risk from women at lower risk, which could decrease the morbimortality of this neoplasm. The current study evaluated the association between polymorphisms rs1820453 and rs11225161 of the Yes-associated protein (YAP) gene in women with breast cancer exposed to arsenic (As) through drinking water. In total, 182 women were assessed for the frequency of YAP rs1820453 and rs11225161 polymorphisms and As urinary levels. The results demonstrated a positive and significant association between breast cancer and smoking, type of drinking water, and levels of AsIII , AsV and inorganic As (iAs) but not the YAP gene polymorphisms evaluated. In conclusion, our data showed that the source of drinking water and AsV and iAs urinary levels increased the risk for breast cancer, but no interactions between YAP gene polymorphisms and As urinary levels were found.
    • Comparative pharmacokinetic study of PEGylated gemcitabine and gemcitabine in rats by LC-MS/MS coupled with pre-column derivatization and MS technique

      Yin, Lei; Ren, Tianming; Zhao, Shiying; Shi, Meiyun; Gu, Jingkai; Univ Arizona, Coll Pharm (ELSEVIER, 2020-01-01)
      Gemcitabine is a small molecular antitumor compound used to treat many types of solid tumors. The clinical application of gemcitabine is limited by its short biological half-life, rapid metabolism and poor tumor tissue targeting. The covalent attachment of polyethylene glycol to gemcitabine is a promising technique to overcome these limitations. After PEGylation, PEGylated gemcitabine could be metabolized into gemcitabine and its metabolites in vivo. Due to the scale effect of PEGylated gemcitabine, the DMPK process of the original drug is greatly changed. Therefore, understanding the pharmacokinetic behavior of PEGylated gemcitabine, gemcitabine and the metabolite dFdU in vivo is really important to clarify the antitumoral activity of these compounds. It would also guide the development of other PEGylated drugs. Due to the complex structure and diverse physiochemical property of PEG, direct quantification analysis of PEGylated gemcitabine presented many challenges in terms of assay sensitivity, selectivity, and robustness. In this article, a data-independent acquisition method, MSALL-based approach using electrospray ionization (ESI) coupled quadrupole time of flight mass spectrometry (MS), was utilized for the determination of PEGylated gemcitabine in rat plasma. The technique consists of a Q1 mass window through all the precursor ions, fragmenting and recording all product ions. PEGylated gemcitabine underwent dissociation in collision cell to generate a series of PEG related ions at m/z 89.0604, 133.0868, 177.1129 of 2, 3, 4 repeating ethylene oxide subunits and PEGylated gemcitabine related ions at m/z 112.0514. PEGylated gemcitabine was detected by the high resolution extracted ions based on the specific compound. For gemcitabine and dFdU, the study used derivatization of these high polarity compounds with dansyl chloride to improve their chromatographic retention. This paper describes comparative pharmacokinetic study of PEGylated gemcitabine and gemcitabine in rats by LC-MS/MS coupled with pre-column derivatization and MSALL technique. The results show that PEGylation could reduce the drug clearance of the conjugated compounds and increase the drug plasma half-life. After administration of PEGylated gemcitabine, the exposure of the free gemcitabine in vivo is lower than administration of gemcitabine, which means that PEGylated gemcitabine possesses lower toxicity compared with gemcitabine.
    • Automatic Detection of Everyday Social Behaviours and Environments from Verbatim Transcripts of Daily Conversations

      Yordanova, Kristina Y.; Demiray, Burcu; Mehl, Matthias R.; Martin, Mike; Univ Arizona, Dept Psychol (IEEE, 2019-03)
      Coding in social sciences is a process that involves the categorisation of qualitative or quantitative data in order to facilitate further analysis. Coding is usually a manual process that involves a lot of effort and time to produce codes with high validity and interrater reliability. Although automated methods for quantitative data analysis are largely used in social sciences, there are only a few attempts at automatically or semi-automatically coding the data collected in qualitative studies. To address this problem, in this work we propose an approach for automated coding of social behaviours and environments based on verbatim transcriptions of everyday conversations. To evaluate the approach, we analysed the transcripts from three datasets containing recordings of everyday conversations from: (1) young healthy adults (German transcriptions), (2) elderly healthy adults (German transcriptions), and (3) young healthy adults (English transcriptions). The results show that it is possible to automatically code the social behaviours and environments based on verbatim transcripts of the recorded conversations. This could reduce the time and effort researchers need to assign accurate codes to transcribed conversations.
    • Collective Action and Governance Activism

      Doidge, Craig; Dyck, Alexander; Mahmudi, Hamed; Virani, Aazam; Univ Arizona, Eller Coll Management (OXFORD UNIV PRESS, 2019-09)
      We examine how an investor collective action organization (ICAO) enhances activism by institutional investors. The ICAO initiated a new form of engagement-private meetings with independent directors to discuss governance proposals. Compared with a single investor acting alone, the ICAO has stronger incentives to engage in activism. Its dollar holdings and voting power are six times larger and predict direct access to the board and the firms it engages. Firms engaged by the ICAO are at least 58% more likely than non-engaged firms to adopt the ICAO's governance proposals that include adoption of majority voting, say-on-pay, and specific compensation policies. Engaged firms also increase CEO incentive pay. An event study around the announcement of the ICAO's formation shows a positive impact on value that increases in both dollar holdings and voting power. We conclude that institutional investors improve governance outcomes through collective action.
    • An Unexpected Romance: Reevaluating the Authorship of the Khosrow-nāma

      O'Malley, Austin; Middle East and North African Studies; Univ Arizona, Sch Middle Eastern & North African Studies (Middle East Medievalists, 2019)
      This article examines the authorship of the Khosrow-nāma, a Perso-Hellenic romance traditionally attributed to ʿAṭṭār. Forty years ago, Shafiʿi-Kadkani laid out a complex argument against ʿAṭṭār’s authorship. He claimed that the attribution was a result of a later forgery, basing his argument on internal chronological evidence, religious and stylistic markers, and the manuscript tradition. The present article systematically evaluates this argument, showing it to be less persuasive than it first appears. First, I introduce new manuscript evidence to demonstrate that the poem was circulating under ʿAṭṭār’s name already before the time of the alleged forgery. I then reassess the internal evidence to show that the Khosrow-nāma could, in fact, fit into a plausible chronology of ʿAṭṭār’s oeuvre. Next, I critique the stylistic and religious arguments against ʿAṭṭār’s authorship, arguing that the romance does not deviate from ʿAṭṭār’s undisputed works nearly as much as is often supposed. I conclude by suggesting that the available data are explained more easily by accepting ʿAṭṭār’s authorship than by adopting the theory of a later forgery.
    • Sediment Respiration Pulses in Intermittent Rivers and Ephemeral Streams

      Bogan, M. T.; Cid, N.; Univ Arizona, Sch Nat Resources & Environm (American Geophysical Union (AGU), 2019-10-16)
      Intermittent rivers and ephemeral streams (IRES) may represent over half the global stream network, but their contribution to respiration and carbon dioxide (CO2) emissions is largely undetermined. In particular, little is known about the variability and drivers of respiration in IRES sediments upon rewetting, which could result in large pulses of CO2. We present a global study examining sediments from 200 dry IRES reaches spanning multiple biomes. Results from standardized assays show that mean respiration increased 32-fold to 66-fold upon sediment rewetting. Structural equation modeling indicates that this response was driven by sediment texture and organic matter quantity and quality, which, in turn, were influenced by climate, land use, and riparian plant cover. Our estimates suggest that respiration pulses resulting from rewetting of IRES sediments could contribute significantly to annual CO2 emissions from the global stream network, with a single respiration pulse potentially increasing emission by 0.2-0.7%. As the spatial and temporal extent of IRES increases globally, our results highlight the importance of recognizing the influence of wetting-drying cycles on respiration and CO2 emissions in stream networks.
    • Assessing Gauge Undercatch Correction in Arctic Basins in Light of GRACE Observations

      Behrangi, Ali; Singh, Alka; Song, Yang; Panahi, Milad; Univ Arizona, Dept Hydrol & Atmospher Sci; Univ Arizona, Dept Geosci (AMER GEOPHYSICAL UNION, 2019-10-09)
      Precipitation measurements at gauges are often considered as reference truth for evaluation of satellite precipitation products. However, gauges may contain large errors. A major source of gauge‐measurement error is snowfall undercatch in high latitudes. We show that the two popular correction factors (CFs) used in the Global Precipitation Climatology Centre monitoring and the Global Precipitation Climatology Project products are different by more than 50%. The CFs can be as large as 3; thus, the choice of CF introduces large uncertainties. Here, in light of observation of storage change from the Gravity Recovery and Climate Experiment (GRACE) and by using the mass conservation principle, we assess the two popular CFs over six Arctic basins. By investigating monthly time series and multiyear precipitation rates over the studied basins using GRACE‐based analysis, the CF based on Fuchs dynamic correction model used in Global Precipitation Climatology Centre monitoring is preferred.