Now showing items 1-20 of 67075

    • Deconstruct to Reconstruct: Challenging Critical Librarianship

      Leung, Sofia; Pho, Annie; MIT; UCLA (The University of Arizona, 2018-11)
      The practice of critical librarianship is often viewed and approached in segmented pieces, due to the nature of specializations within the profession. Those who engage and practice critical librarianship often may focus on certain areas like pedagogy, archival theory, classification or categorization, and scholarly communication, among other topics. This presentation will deconstruct the core values of librarianship and rhetoric within critical librarianship in order to begin reconstructing and reimagining how libraries can explicitly center marginalized communities. We want to build a broader framework that explicitly draws the connections/relationships between critical pedagogy (how we teach), critical information literacy (what we teach), and the infrastructure, policies, and practices of the libraries within which we work. We will challenge western knowledge practices and engage participants in collectively developing a new framework of librarianship that will inform and shape our pedagogy.
    • Increases in plasma corin levels following experimental myocardial infarction reflect the severity of ischemic injury

      Wang, Dong; Gladysheva, Inna P.; Sullivan, Ryan D.; Fan, Tai-Hwang M.; Mehta, Radhika M.; Tripathi, Ranjana; Sun, Yao; Reed, Guy L.; Univ Arizona, Coll Med, Dept Internal Med (PUBLIC LIBRARY SCIENCE, 2018-09-07)
      Following acute myocardial infarction, clinical studies show alterations in the blood levels of corin, a cardiac-selective activator of the natriuretic peptides pro-atrial natriuretic peptide (pro-ANP) and pro-B-type natriuretic peptide (pro-BNP). However, the temporal changes in circulating and cardiac corin levels and their relationships to the severity of myocardial infarction have not been studied. The main objective of this study was to examine the relationship between cardiac and circulating corin levels and their association with cardiac systolic function and infarct size during the early phase of acute myocardial infarction (<72 h) in a translationally relevant induced coronary ligation mouse model. This acute phase timeline was chosen to correlate with the clinical practice within which blood samples are collected from myocardial infarction patients. Heart and plasma samples were examined at 3, 24, and 72 hours post acute myocardial infarction. Plasma corin levels were examined by enzyme-linked immunosorbent assay, transcripts of cardiac corin, pro-ANP and pro-BNP by quantitative real-time polymerase chain reaction, cardiac corin expression by immunohistology, infarct size by histology and heart function by echocardiography. Plasma corin levels were significantly increased at 3 (P<0.05), 24 (P<0.001), and 72 hours (P<0.01) post-acute myocardial infarction. In contrast, cardiac corin transcript levels dropped by 5% (P>0.05), 69% (P<0.001) and 65% (P<0.001) and immunoreactive cardiac corin protein levels dropped by 30% (P<0.05), 76% (P<0.001) and 75% (P<0.001), while cardiac pro-ANP and pro-BNP transcript levels showed an opposite pattern. Plasma corin levels were negatively correlated with immunoreactive cardiac corin (P<0.01), ejection fraction (P<0.05) and fractional shortening (P<0.05), but positively correlated with infarct size (P<0.01). In conclusion, acute myocardial infarction induces rapid increases in plasma corin and decreases in cardiac corin levels. In the early phase of acute myocardial infarction, plasma corin levels are inversely correlated with heart function and may reflect the severity of myocardial damage.
    • Geologic map of the Dragoon 7 ½ ' Quadrangle, Cochise County, Arizona

      Johnson, B.J.; Cook, J.P.; Ferguson, C.A.; Arizona Geological Survey (Arizona Geological Survey (Tucson, AZ), 2018-12-28)
    • Imaging-based clusters in current smokers of the COPD cohort associate with clinical characteristics: the SubPopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS)

      Haghighi, Babak; Choi, Sanghun; Choi, Jiwoong; Hoffman, Eric A.; Comellas, Alejandro P.; Newell, John D.; Graham Barr, R.; Bleecker, Eugene; Cooper, Christopher B.; Couper, David; Han, Mei Lan; Hansel, Nadia N.; Kanner, Richard E.; Kazerooni, Ella A.; Kleerup, Eric A. C.; Martinez, Fernando J.; O’Neal, Wanda; Rennard, Stephen I.; Woodruff, Prescott G.; Lin, Ching-Long; Univ Arizona, Dept Med, Div Genet Genom & Precis Med (BMC, 2018-09-18)
      Background: Classification of COPD is usually based on the severity of airflow, which may not sensitively differentiate subpopulations. Using a multiscale imaging-based cluster analysis (MICA), we aim to identify subpopulations for current smokers with COPD. Methods: Among the SPIROMICS subjects, we analyzed computed tomography images at total lung capacity (TLC) and residual volume (RV) of 284 current smokers. Functional variables were derived from registration of TLC and RV images, e.g. functional small airways disease (fSAD%). Structural variables were assessed at TLC images, e.g. emphysema and airway wall thickness and diameter. We employed an unsupervised method for clustering. Results: Four clusters were identified. Cluster 1 had relatively normal airway structures; Cluster 2 had an increase of fSAD% and wall thickness; Cluster 3 exhibited a further increase of fSAD% but a decrease of wall thickness and airway diameter; Cluster 4 had a significant increase of fSAD% and emphysema. Clinically, Cluster 1 showed normal FEV1/FVC and low exacerbations. Cluster 4 showed relatively low FEV1/FVC and high exacerbations. While Cluster 2 and Cluster 3 showed similar exacerbations, Cluster 2 had the highest BMI among all clusters. Conclusions: Association of imaging-based clusters with existing clinical metrics suggests the sensitivity of MICA in differentiating subpopulations.
    • Higher levels of trait emotional awareness are associated with more efficient global information integration throughout the brain: a graph-theoretic analysis of resting state functional connectivity

      Smith, Ryan; Sanova, Anna; Alkozei, Anna; Lane, Richard D; Killgore, William D S; Univ Arizona, Dept Psychiat (OXFORD UNIV PRESS, 2018-07)
      Previous studies have suggested that trait differences in emotional awareness (tEA) are clinically relevant, and associated with differences in neural structure/function. While multiple leading theories suggest that conscious awareness requires widespread information integration across the brain, no study has yet tested the hypothesis that higher tEA corresponds to more efficient brain-wide information exchange. Twenty-six healthy volunteers (13 females) underwent a resting state functional magnetic resonance imaging scan, and completed the Levels of Emotional Awareness Scale (LEAS; a measure of tEA) and the Wechsler Abbreviated Scale of Intelligence (WASI-II; a measure of general intelligence quotient [IQ]). Using a whole-brain (functionally defined) region of interest (ROI) atlas, we computed several graph theory metrics to assess the efficiency of brain-wide information exchange. After statistically controlling for differences in age, gender and IQ we first observed a significant relationship between higher LEAS scores and greater average degree (i.e. overall whole-brain network density). When controlling for average degree, we found that higher LEAS scores were also associated with shorter average path lengths across the collective network of all included ROIs. These results jointly suggest that individuals with higher tEA display more efficient global information exchange throughout the brain. This is consistent with the idea that conscious awareness requires global accessibility of represented information.
    • ER-associated ubiquitin ligase HRD1 programs liver metabolism by targeting multiple metabolic enzymes

      Wei, Juncheng; Yuan, Yanzhi; Chen, Lu; Xu, Yuanming; Zhang, Yuehui; Wang, Yajun; Yang, Yanjie; Peek, Clara Bien; Diebold, Lauren; Yang, Yi; Gao, Beixue; Jin, Chaozhi; Melo-Cardenas, Johanna; Chandel, Navdeep S.; Zhang, Donna D.; Pan, Hui; Zhang, Kezhong; Wang, Jian; He, Fuchu; Fang, Deyu; Univ Arizona, Dept Pharmacol & Toxicol (NATURE PUBLISHING GROUP, 2018-09-10)
      The HMG-CoA reductase degradation protein 1 (HRD1) has been identified as a key enzyme for endoplasmic reticulum-associated degradation of misfolded proteins, but its organ-specific physiological functions remain largely undefined. Here we show that mice with HRD1 deletion specifically in the liver display increased energy expenditure and are resistant to HFD-induced obesity and liver steatosis and insulin resistance. Proteomic analysis identifies a HRD1 interactome, a large portion of which includes metabolic regulators. Loss of HRD1 results in elevated ENTPD5, CPT2, RMND1, and HSD17B4 protein levels and a consequent hyperactivation of both AMPK and AKT pathways. Genome-wide mRNA sequencing revealed that HRD1-deficiency reprograms liver metabolic gene expression profiles, including suppressing genes involved in glycogenesis and lipogenesis and upregulating genes involved in glycolysis and fatty acid oxidation. We propose HRD1 as a liver metabolic regulator and a potential drug target for obesity, fatty liver disease, and insulin resistance associated with the metabolic syndrome.
    • Employing Bessel-Gaussian Beams to Improve Physical-Layer Security in Free-Space Optical Communications

      Wang, Tyan-Lin; Gariano, John A.; Djordjevic, Ivan B.; Univ Arizona, Coll Opt Sci; Univ Arizona, Dept Elect & Comp Engn (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018-09)
      Physical-layer security in free-space optical communications channels can be compromised when an eavesdropper performs optical beam-splitting attacks over an atmospheric channel. Previous simulations have shown that Laguerre-Gaussian orbital angular momentum-carrying beams can provide higher secrecy capacities compared to that of ordinary Gaussian beams. In this paper, we determine if Bessel-Gaussian beams can provide further improvement over their corresponding Laguerre-Gaussian counterparts. Using computer simulations and experiments with spatial light modulators, an increase in secrecy capacity of 10 to 30 bits/sec/Hz in the weak to medium turbulence regimes is demonstrated. This verifies that Bessel-Gaussian beams have more resiliency to atmospheric turbulence effects than Laguerre-Gaussian beams. Furthermore, research on optimizing the quality of these beams can help to realize a practical system for more secure communications.
    • Diverse Protoplanetary Disk Morphology Produced by a Jupiter-mass Planet

      Bae, Jaehan; Pinilla, Paola; Birnstiel, Tilman; Univ Arizona, Dept Astron, Steward Observ (IOP PUBLISHING LTD, 2018-09-10)
      Combining hydrodynamic planet-disk interaction simulations with dust evolution models, we show that protoplanetary disks with a giant planet can reveal diverse morphology in (sub)millimeter continuum, including a full disk without significant radial structure, a transition disk with an inner cavity, a disk with a single gap and a central continuum peak, and a disk with multiple rings and gaps. Such diversity originates from (1) the level of viscous transport in the disk, which determines the number of gaps a planet can open; (2) the size and spatial distributions of grains determined by the coagulation, fragmentation, and radial drift, which in turn affects the emissivity of the disk at (sub)millimeter wavelengths; and (3) the angular resolution used to observe the disk. In particular, our results show that disks with the same underlying gas distribution can have very different grain size/spatial distributions and thus appearance in continuum, depending on the interplay among coagulation, fragmentation, and radial drift. This suggests that proper treatments for the grain growth have to be included in models of protoplanetary disks concerning continuum properties and that complementary molecular line observations are highly desired in addition to continuum observations to reveal the true nature of disks. The fact that a single planet can produce diverse disk morphology emphasizes the need to search for more direct, localized signatures of planets in order to confirm (or dispute) the planetary origin of observed ringed substructures.
    • Divergent behavior amid convergent evolution: A case of four desert rodents learning to respond to known and novel vipers.

      Bleicher, Sonny Shlomo; Kotler, Burt P; Shalev, Omri; Dixon, Austin; Embar, Keren; Brown, Joel S; Univ Arizona, Tumamoc People & Habitat, Dept Ecol & Evolutionary Biol (PUBLIC LIBRARY SCIENCE, 2018-08-20)
      Desert communities world-wide are used as natural laboratories for the study of convergent evolution, yet inferences drawn from such studies are necessarily indirect. Here, we brought desert organisms together (rodents and vipers) from two deserts (Mojave and Negev). Both predators and prey in the Mojave have adaptations that give them competitive advantage compared to their middle-eastern counterparts. Heteromyid rodents of the Mojave, kangaroo rats and pocket mice, have fur-lined cheek pouches that allow them to carry larger loads of seeds under predation risk compared to gerbilline rodents of the Negev Deserts. Sidewinder rattlesnakes have heat-sensing pits, allowing them to hunt better on moonless nights when their Negev sidewinding counterpart, the Saharan horned vipers, are visually impaired. In behavioral-assays, we used giving-up density (GUD) to gauge how each species of rodent perceived risk posed by known and novel snakes. We repeated this for the same set of rodents at first encounter and again two months later following intensive "natural" exposure to both snake species. Pre-exposure, all rodents identified their evolutionarily familiar snake as a greater risk than the novel one. However, post-exposure all identified the heat-sensing sidewinder rattlesnake as a greater risk. The heteromyids were more likely to avoid encounters with, and discern the behavioral difference among, snakes than their gerbilline counterparts.
    • Discovery of Extended Infrared Emission around the Neutron Star RXJ0806.4–4123

      Posselt, B.; Pavlov, G. G.; Ertan, Ü.; Çalışkan, S.; Luhman, K. L.; Williams, C. C.; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2018-09-20)
      Following up on a faint detection of a near-infrared (NIR) source at the position of the X-ray thermal isolated neutron star RXJ0806.4-4123, we present new Hubble Space Telescope observations in the H-band. The NIR source is unambiguously detected with a Vega magnitude of 23.7 +/- 0.2 (flux density of 0.40 +/- 0.06 mu Jy at lambda = 1.54 mu m). The source position is coincident with the neutron star position, and the implied NIR flux is strongly in excess of what one would expect from an extrapolation of the optical-UV spectrum of RXJ0806.4-4123. The NIR source is extended, with a size of at least 0 8, and shows some asymmetry. The conservative upper limit on the flux contribution of a point source is 50%. Emission from gas and dust in the ambient diffuse interstellar medium can be excluded as a cause for the extended emission. The source parameters are consistent with an interpretation as either the first NIR-only detected pulsar wind nebula or the first resolved disk around an isolated neutron star.
    • Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70

      Keppler, M.; Benisty, M.; Müller, A.; Henning, Th.; van Boekel, R.; Cantalloube, F.; Ginski, C.; van Holstein, R. G.; Maire, A.-L.; Pohl, A.; Samland, M.; Avenhaus, H.; Baudino, J.-L.; Boccaletti, A.; de Boer, J.; Bonnefoy, M.; Chauvin, G.; Desidera, S.; Langlois, M.; Lazzoni, C.; Marleau, G.-D.; Mordasini, C.; Pawellek, N.; Stolker, T.; Vigan, A.; Zurlo, A.; Birnstiel, T.; Brandner, W.; Feldt, M.; Flock, M.; Girard, J.; Gratton, R.; Hagelberg, J.; Isella, A.; Janson, M.; Juhasz, A.; Kemmer, J.; Kral, Q.; Lagrange, A.-M.; Launhardt, R.; Matter, A.; Ménard, F.; Milli, J.; Mollière, P.; Olofsson, J.; Pérez, L.; Pinilla, P.; Pinte, C.; Quanz, S. P.; Schmidt, T.; Udry, S.; Wahhaj, Z.; Williams, J. P.; Buenzli, E.; Cudel, M.; Dominik, C.; Galicher, R.; Kasper, M.; Lannier, J.; Mesa, D.; Mouillet, D.; Peretti, S.; Perrot, C.; Salter, G.; Sissa, E.; Wildi, F.; Abe, L.; Antichi, J.; Augereau, J.-C.; Baruffolo, A.; Baudoz, P.; Bazzon, A.; Beuzit, J.-L.; Blanchard, P.; Brems, S. S.; Buey, T.; De Caprio, V.; Carbillet, M.; Carle, M.; Cascone, E.; Cheetham, A.; Claudi, R.; Costille, A.; Delboulbé, A.; Dohlen, K.; Fantinel, D.; Feautrier, P.; Fusco, T.; Giro, E.; Gluck, L.; Gry, C.; Hubin, N.; Hugot, E.; Jaquet, M.; Le Mignant, D.; Llored, M.; Madec, F.; Magnard, Y.; Martinez, P.; Maurel, D.; Univ Arizona, Dept Astron (EDP SCIENCES S A, 2018-09-12)
      Context. Young circumstellar disks are the birthplaces of planets. Their study is of prime interest to understand the physical and chemical conditions under which planet formation takes place. Only very few detections of planet candidates within these disks exist, and most of them are currently suspected to be disk features. Aims. In this context, the transition disk around the young star PDS 70 is of particular interest, due to its large gap identified in previous observations, indicative of ongoing planet formation. We aim to search for the presence of an embedded young planet and search for disk structures that may be the result of disk-planet interactions and other evolutionary processes. Methods. We analyse new and archival near-infrared images of the transition disk PDS 70 obtained with the VLT/SPHERE, VLT/NaCo, and Gemini/NICI instruments in polarimetric differential imaging and angular differential imaging modes. Results. We detect a point source within the gap of the disk at about 195 mas (similar to 22 au) projected separation. The detection is confirmed at five different epochs, in three filter bands and using different instruments. The astrometry results in an object of bound nature, with high significance. The comparison of the measured magnitudes and colours to evolutionary tracks suggests that the detection is a companion of planetary mass. The luminosity of the detected object is consistent with that of an L-type dwarf, but its IR colours are redder, possibly indicating the presence of warm surrounding material. Further, we confirm the detection of a large gap of similar to 54 au in size within the disk in our scattered light images, and detect a signal from an inner disk component. We find that its spatial extent is very likely smaller than similar to 17 au in radius, and its position angle is consistent with that of the outer disk. The images of the outer disk show evidence of a complex azimuthal brightness distribution which is different at different wavelengths and may in part be explained by Rayleigh scattering from very small grains. Conclusions. The detection of a young protoplanet within the gap of the transition disk around PDS 70 opens the door to a so far observationally unexplored parameter space of planetary formation and evolution. Future observations of this system at different wavelengths and continuing astrometry will allow us to test theoretical predictions regarding planet-disk interactions, planetary atmospheres, and evolutionary models.
    • Common and Unique Neural Systems Underlying the Working Memory Maintenance of Emotional vs. Bodily Reactions to Affective Stimuli: The Moderating Role of Trait Emotional Awareness

      Smith, Ryan; Lane, Richard D.; Sanova, Anna; Alkozei, Anna; Smith, Courtney; Killgore, William D. S.; Univ Arizona, Dept Psychiat (FRONTIERS MEDIA SA, 2018-09-18)
      Many leading theories suggest that the neural processes underlying the experience of one's own emotional reactions partially overlap with those underlying bodily perception (i.e., interoception, somatosensation, and proprioception). However, the goal-directed maintenance of one's own emotions in working memory (EWM) has not yet been compared to WM maintenance of one's own bodily reactions (BWM). In this study, we contrasted WM maintenance of emotional vs. bodily reactions to affective stimuli in 26 healthy individuals while they underwent functional magnetic resonance imaging. Specifically, we examined the a priori hypothesis that individual differences in trait emotional awareness (tEA) would lead to greater differences between these two WM conditions within medial prefrontal cortex (MPFC). We observed that MPFC activation during EWM (relative to BWM) was positively associated with tEA. Whole-brain analyses otherwise suggested considerable similarity in the neural activation patterns associated with EWM and BWM. In conjunction with previous literature, our findings not only support a central role of body state representation/maintenance in EWM, but also suggest greater engagement of MPFC-mediated conceptualization processes during EWM in those with higher tEA.
    • Astrolabe: Curating, Linking, and Computing Astronomy’s Dark Data

      Heidorn, P. Bryan; Stahlman, Gretchen R.; Steffen, Julie; Univ Arizona, Sch Informat (IOP PUBLISHING LTD, 2018-05)
      Where appropriate repositories are not available to support all relevant astronomical data products, data can fall into darkness: unseen and unavailable for future reference and reuse. Some data in this category are legacy or old data, but newer data sets are also often uncurated and could remain dark. This paper provides a description of the design motivation and development of Astrolabe, a cyberinfrastructure project that addresses a set of community recommendations for locating and ensuring the long-term curation of dark or otherwise at-risk data and integrated computing. This paper also describes the outcomes of the series of community workshops that informed creation of Astrolabe. According to participants in these workshops, much astronomical dark data currently exist that are not curated elsewhere, as well as software that can only be executed by a few individuals and therefore becomes unusable because of changes in computing platforms. Astronomical research questions and challenges would be better addressed with integrated data and computational resources that fall outside the scope of existing observatory and space mission projects. As a solution, the design of the Astrolabe system is aimed at developing new resources for management of astronomical data. The project is based in CyVerse cyberinfrastructure technology and is a collaboration between the University of Arizona and the American Astronomical Society. Overall, the project aims to support open access to research data by leveraging existing cyberinfrastructure resources and promoting scientific discovery by making potentially useful data available to the astronomical community, in a computable format.
    • An Updated Line List for NUV Spectral Synthesis in Evolved Stars: Redetermination of the Beryllium Abundance in the Solar Photosphere

      Carlberg, Joleen K.; Cunha, Katia; Smith, Verne V.; Nascimento, José-Dias do; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2018-09-20)
      Motivated by the desire to measure beryllium abundances in red giant stars, we have constructed a new line list for synthesizing spectra in the near-ultraviolet. Using the Sun, Arcturus, and Pollux as benchmark stars, we explore potential sources of missing continuous opacity and line absorption. Despite the inclusion of new sources of continuous opacity, fitting the ultraviolet OH lines in the solar spectrum still requires artificially inflating the continuous opacity. The red giants also require the addition of a line of unknown origin in the blue wing of the Be line at lambda 3131.065 angstrom, and we find a good match can be made by adopting a Ti II line with low excitation potential. The inclusion of this line does not affect the measurement of the solar Be abundance. Because the fits to all of the benchmark stars require tuning the properties of known spectral lines and including both an unknown source of additional continuous opacity and spectral lines of unknown origin, we argue that the absolute abundances of Be in stars should be interpreted with caution. Therefore, the question of whether the solar Be abundance is depleted may not yet be resolved, although our model favors minimal Be depletion in the Sun.
    • ABC transporter mis-splicing associated with resistance to Bt toxin Cry2Ab in laboratory- and field-selected pink bollworm

      Mathew, Lolita G.; Ponnuraj, Jeyakumar; Mallappa, Bheemanna; Chowdary, Lingutla R.; Zhang, Jianwei; Tay, Wee Tek; Walsh, Thomas K.; Gordon, Karl H. J.; Heckel, David G.; Downes, Sharon; Carrière, Yves; Li, Xianchun; Tabashnik, Bruce E.; Fabrick, Jeffrey A.; Univ Arizona, Arizona Genom Inst; Univ Arizona, Dept Entomol (NATURE PUBLISHING GROUP, 2018-09-10)
      Evolution of pest resistance threatens the benefits of genetically engineered crops that produce Bacillus thuringiensis (Bt) insecticidal proteins. Strategies intended to delay pest resistance are most effective when implemented proactively. Accordingly, researchers have selected for and analyzed resistance to Bt toxins in many laboratory strains of pests before resistance evolves in the field, but the utility of this approach depends on the largely untested assumption that laboratory-and field-selected resistance to Bt toxins are similar. Here we compared the genetic basis of resistance to Bt toxin Cry2Ab, which is widely deployed in transgenic crops, between laboratory-and field-selected populations of the pink bollworm (Pectinophora gossypiella), a global pest of cotton. We discovered that resistance to Cry2Ab is associated with mutations disrupting the same ATP-binding cassette transporter gene (PgABCA2) in a laboratory-selected strain from Arizona, USA, and in field-selected populations from India. The most common mutation, loss of exon 6 caused by alternative splicing, occurred in resistant larvae from both locations. Together with previous data, the results imply that mutations in the same gene confer Bt resistance in laboratory-and field-selected strains and suggest that focusing on ABCA2 genes may help to accelerate progress in monitoring and managing resistance to Cry2Ab.
    • Effects of Structural Motion on Separation and Separation Control: An Integrated Investigation using Numerical Simulations, Theory, Wind-Tunnel and Free-Flight Experiments

      Fasel, Hermann F.; Hosseinverdi, Shirzad; Jesse, Little; Gross, Andreas (TU Braunschweig – Niedersächsisches Forschungszentrum für Luftfahrt, 2017-01)
      A combined investigative approach which employs high-fidelity numerical simulations, wind & water-tunnel and free-flight experiments is taken to investigate the fundamental flow physics of separation and separation control for wing sections undergoing temporal motions. Detailed investigations of the underlying unsteady flow physics have been carried out for the X-56A airfoil at nominal angles of attack of 10 and 12 degrees for Re = 200k. The reduced frequency of the structural motion is k=0.7 and the plunging amplitude is 3.2% and 4.8% of the chord length. For 10deg AoA, the agreement between the measurements, simulations, and Theodorsen's theory is good even though the instantaneous angles of attack during the airfoil oscillations are outside the linear CL - AoA regime and extend into the region associated with static stall. As the angle of attack is increased to 12deg, the flow over the suction surface of the wing begins to intermittently separate and Theodorsen's theory fails. Experiments and simulations show strong qualitative agreement and both capture "bursting" of the laminar separation bubble near the leading edge of the airfoil. Furthermore, highly resolved Direct Numerical Simulations (DNS) were performed in order to investigate the hydrodynamic instability mechanisms and transition to turbulence in swept laminar separation bubbles.
    • A considerable fraction of soil-respired CO2 is not emitted directly to the atmosphere

      Sánchez-Cañete, Enrique P.; Barron-Gafford, Greg A.; Chorover, Jon; Univ Arizona, B2 Earthsci, Biosphere 2; Univ Arizona, Sch Geog & Dev; Univ Arizona, Dept Soil Water & Environm Sci (NATURE PUBLISHING GROUP, 2018-09-10)
      Soil CO2 efflux (F-soil) is commonly considered equal to soil CO2 production (R-soil), and both terms are used interchangeably. However, a non-negligible fraction of R-soil can be consumed in the subsurface due to a host of disparate, yet simultaneous processes. The ratio between CO2 efflux/O-2 influx, known as the apparent respiratory quotient (ARQ), enables new insights into CO2 losses from R-soil not previously captured by F-soil. We present the first study using continuous ARQ estimates to evaluate annual CO2 losses of carbon produced from R-soil. We found that up to 1/3 of R-soil was emitted directly to the atmosphere, whereas 2/3 of R-soil was removed by subsurface processes. These subsurface losses are attributable to dissolution in water, biological activities and chemical reactions. Having better estimates of R-soil is key to understanding the true influence of ecosystem production on R-soil, as well as the role of soil CO2 production in other connected processes within the critical zone.
    • A historical perspective on treatment of fuchs' endothelial dystrophy: We have come a long way

      Moshirfar, Majid; Ding, Yanning; Shah, TirthJ; Univ Arizona, Coll Med (LIPPINCOTT WILLIAMS & WILKINS, 2018)
      Fuchs' endothelial corneal dystrophy is a hereditary and progressive vision-threatening disease with a high prevalence in our adult population. In the past two decades, endothelial transplantation has dramatically changed the way we treat these patients. Back then, our limited surgical techniques often resulted in less than ideal outcomes. It was unimaginable for our patients to achieve near perfect visual acuity in such a short span of time. Over the years, we have tenaciously refined our surgical techniques to vastly improve patient outcomes, and with the recent advent of Rho-kinase inhibitors, we may even consider delivering a simple injection to our patients in the future. Our purpose is to take a historical perspective on how far we have come in treating this disorder and how rapidly this field will continue to evolve.
    • Sodium polystyrene sulfonate induced intestinal necrosis; a case report

      Almulhim, Abdulaziz Saleh; Hall, Edina; Mershid Al Rehaili, Bassam; Almulhim, Abdulmuhsin Saleh; Univ Arizona, Coll Pharm (ELSEVIER SCIENCE BV, 2018-09)
      Background: Hyperkalemia is a commonly encountered medical problem. The treatment of hyperkalemia involves the use of pharmacological agents with different mechanism of actions. Sodium Polystyrene sulfonate (SPS) is a cation-exchange resin that exchanges sodium for potassium. In 2009, the United States Food and Drug Administration issued warning against the use of SPS with sorbitol due to risk of colonic necrosis. We present a case of SPS induced colonic necrosis in the absence of sorbitol and risk factors deemed to increase risk of colonic necrosis. Case report: Here we report a 64-year old male with past medical history of kidney stones who was admitted for treatment of colitis which was complicated by septic shock requiring vasopressors. His course was further complicated by hyperkalemia attributed to acute kidney injury. One dose 30 gm of SPS was administered which normalized his serum potassium. The patient's course was complicated by duodenal ulcer, and colonic perforation. The initial pathology findings of the resected specimen were suggestive of inflammatory bowel disease which resulted in starting patient on mesalamine. The patient then developed fistula which was resected and sent for pathology. SPS induced colonic necrosis was made based on the pathology findings. Conclusion: SPS is commonly used to decrease potassium levels. SPS has been reported to be associated with several gastrointestinal complications. FDA issued warning against the use of SPS in patients at risk for complications. Here we report a case with SPS induced colonic necrosis in the absence of risk factors reported in the literature. (C) 2018 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.
    • Imperfect Alternatives: Institutional Choice and the Reform of Investment Law

      Puig, Sergio; Shaffer, Gregory; Univ Arizona, James E Rogers Coll Law (CAMBRIDGE UNIV PRESS, 2018-07)
      This Article applies the theory of comparative institutional analysis to evaluate the trade-offs associated with alternative mechanisms for resolving investment disputes. We assess the trade-offs in light of the principle of accountability under the rule of law, which underpins the goals of fairness, efficiency, and peace that are attributed to investment law. The Article makes two recommendations: first, reforms should address complementarity between domestic and international institutions; second, institutional choices should respond to the different contexts that states face.