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Sample records for experiments mimicking crustal

  1. Stress-wave experiments on selected crustal rocks and minerals

    Science.gov (United States)

    Grady, D. E.

    1983-09-01

    Large amplitude compressive stress wave experiments on selected crustal rocks and minerals was performed. The materials studied included Vermont marble, Blair dolomite, Oakhall limestone, z-cut calcite and oil shale. In each case specific constitutive features were studied. Features include interrelation of plastic yielding and phase transformation, rate dependent plastic flow, dilatency under dynamic loading conditions, and energy dissipation at stress amplitudes below measured Hugoniot elastic limits. A new experimental method using inmaterial mutual inductance magnetic gauges is also described.

  2. The 1978 Yellowstone-Eastern Snake River Plain Seismic Profiling Experiment: Crustal structure of the Yellowstone Region and experiment design

    Science.gov (United States)

    Smith, R. B.; Schilly, M. M.; Braile, L. W.; Ansorge, J.; Lehman, J. L.; Baker, M. R.; Prodehl, C.; Healy, J. H.; Mueller, S.; Greensfelder, R. W.

    1982-04-01

    In 1978 a major seismic profiling experiment was conducted in the Yellowstone-eastern Snake River Plain region of Idaho and Wyoming. Fifteen shots were recorded that provided coverage to distances of 300 km. In this paper, travel time and synthetic seismogram modeling was used to evaluate an average P wave velocity and apparent Q structure of the crust from two seismic profiles (reversed) across the Yellowstone National Park region. This area includes the well-known hydrothermal features of Yellowstone National Park (geysers, fumeroles, etc.), a large collapse caldera, and extensive silicic volcanism of Quaternary age—features attributed to shallow crustal sources of magma. The averaged crustal structure for this region as interpreted from the seismic data consists of (1) a highly variable, near-surface layer approximately 2 km thick with variable velocities of 3.0 to 4.8 km/s and a low apparent Q of 30 that is interpreted to be composed of weathered rhyolites and sedimentary infill, (2) an upper crustal layer 3 to 4 km thick with variable velocities of 4.9 to 5.5 km/s and apparent Q of 50 to 200 that is thought to represent the accumulation of the Pleistocene-Quaternary rhyolite flows, ash flow tuffs, and possible Paleozoic and Precambrian metamorphic equivalents, (3) the crystalline, upper crust that is characterized by a laterally inhomogeneous layer that varies in velocity from 4.0 to 6.1 km/s, averaging 5 km thick with a Q of 300. This layer appears to be a cooling but still hot body of granitic composition beneath the Yellowstone caldera. It is thought to be a remnant of the magma chambers that produced the Quaternary silicic volcanic rocks of the Yellowstone Plateau and may still be a major contributor to the high heat flow, (4) a laterally homogeneous intermediate crustal layer 8 to 10 km thick with a velocity of 6.5 km/s and apparent Q of 100 to 300, (5) a homogeneous 25-km-thick lower crust with a velocity of 6.7 to 6.8 km/s and an apparent Q of 300

  3. MR imaging of musculoskeletal tumors and tumor mimickers with intravenous gadolinium: experience with 242 patients

    Energy Technology Data Exchange (ETDEWEB)

    May, D.A. [Department of Radiology, Wilford Hall USAF Medical Center, San Antonio, TX (United States)]|[WHMC/PSRD, Lackland AFB, TX (United States); Good, R.B. [Department of Radiology, Wilford Hall USAF Medical Center, San Antonio, TX (United States); Smith, D.K. [Department of Radiology, Wilford Hall USAF Medical Center, San Antonio, TX (United States); Parsons, T.W. [Department of Orthopaedic Surgery, Wilford Hall USAF Medical Center, San Antonio, TX (United States)

    1997-01-01

    Purpose. This pictorial essay reviews our experience with MR scans with gadolinium in patients with musculoskeletal tumors and tumor mimickers. Design. Review of 242 MR scans obtained in the initial evaluation of a possible primary musculoskeletal neoplasm. All scans included a T1-weighted, fat-suppressed sequence following intravenous administration of gadolinium. Results. MR scans with gadolinium did not contribute to differential diagnosis or patient management in 89% of the patients in this series. However, intravenous gadolinium did assist in guiding the biopsy of bulky lesions and evaluating treated tumor beds for possible recurrence. MR scans with gadolinium were sometimes helpful when the differential diagnosis included synovitis, Morton`s neuroma or intramuscular myxoma, and when it was important to differentiate cystic from solid lesions. Conclusions. Routine use of gadolinium in every initial MR examination of a possible musculoskeletal mass is not warranted. However, there are appropriate selected indications for gadolinium administration as outlined above. (orig.). With 19 figs., 1 tab.

  4. The Yellowstone-Snake River Plain Seismic Profiling Experiment: Crustal structure of the Eastern Snake River Plain

    Science.gov (United States)

    Braile, L. W.; Smith, R. B.; Ansorge, J.; Baker, M. R.; Sparlin, M. A.; Prodehl, C.; Schilly, M. M.; Healy, J. H.; Mueller, St.; Olsen, K. H.

    1982-04-01

    Seismic refraction profiles recorded along the eastern Snake River Plain (ESRP) in southeastern Idaho during the 1978 Yellowstone-Snake River Plain cooperative seismic profiling experiment are interpreted to infer the crustal velocity and attenuation (Q-1) structure of the ESRP. Travel-time and synthetic seismogram modeling of a 250 km reversed refraction profile as well as a 100 km detailed profile indicate that the crust of the ESRP is highly anomalous. Approximately 3 to 6 km of volcanic rocks (with some interbedded sediments) overlie an upper-crustal layer (compressional velocity ≅6.1 km/s) which thins southwestward along the ESRP from a thickness of 10 km near Island Park Caldera to 2 to 3 km beneath the central and southwestern portions of the ESRP. An intermediate-velocity (≅6.5 km/s) layer extends from ≅10 to ≅20 km depth. A thick (≅22 km) lower crust of compressional velocity 6.8 km/s, a total crustal thickness of ≅42 km, and a Pn velocity of ≅7.9 km/s is observed in the ESRP, similar to the western Snake River Plain and the Rocky Mountains Provinces. High attenuation is evident on the amplitude corrected seismic data due to low-Q values in the volcanic rocks (Qp = 20 to 200) and throughout the crust (Qp = 160 to 300). Based on these characteristics of the crustal structure and volcanic-age progression data, it is suggested that the ESRP has resulted from an intensive period of intrusion of mantle-derived basaltic magma into the upper crust generating explosive silicic volcanism and associated regional uplift and caldera collapse. This activity began about 15 m.y. ago in southwestern Idaho and has migrated northeast to its present position at Yellowstone. Subsequent cooling of the intruded upper crust results in the 6.5 km/s velocity intermediate layer. Crustal subsidence and periodic basaltic volcanism as represented by the ESRP complete the sequence of crustal evolution.

  5. The PROTEUS Experiment: Active Source Seismic Imaging of the Crustal Magma Plumbing Structure of the Santorini Arc Volcano

    Science.gov (United States)

    Hooft, E. E. E.; Morgan, J. V.; Nomikou, P.; Toomey, D. R.; Papazachos, C. V.; Warner, M.; Heath, B.; Christopoulou, M. E.; Lampridou, D.; Kementzetzidou, D.

    2016-12-01

    The goal of the PROTEUS seismic experiment (Plumbing Reservoirs Of The Earth Under Santorini) is to examine the entire crustal magma plumbing system beneath a continental arc volcano and determine the magma geometry and connections throughout the crust. These physical parameters control magma migration, storage, and eruption and inform the question of how physical and chemical processing of magma at arc volcanoes forms the andesitic rock compositions that dominate the lower continental crust. These physical parameters are also important to understand volcanic-tectonic interactions and geohazards. Santorini is ideal for these goals because the continental crust has been thinned by extension and so the deep magmatic system is more accessible, also it is geologically well studied. Since the volcano is a semi-submerged, it was possible to collect a unique 3D marine-land active source seismic dataset. During the PROTEUS experiment in November-December of 2015, we recorded 14,300 marine sound sources from the US R/V Langseth on 89 OBSIP short period ocean bottom seismometers and 60 German and 5 Greek land seismometers. The experiment was designed for high-density spatial sampling of the seismic wavefield to allow us to apply two state-of-the-art 3D inversion methods: travel time tomography and full waveform inversion. A preliminary travel time tomography model of the upper crustal seismic velocity structure of the volcano and surrounding region is presented in an accompanying poster. We also made marine geophysical maps of the seafloor using multi-beam bathymetry and of the gravity and magnetic fields. The new seafloor map reveals the detailed structure of the major fault system between Santorini and Amorgos, of associated landslides, and of newly discovered volcanic features. The PROTEUS project will provide new insights into the structure of the whole crustal magmatic system of a continental arc volcano and its evolution within the surrounding tectonic setting.

  6. Primary crustal melt compositions: Insights into the controls, mechanisms and timing of generation from kinetics experiments and melt inclusions

    Science.gov (United States)

    Acosta-Vigil, Antonio; London, David; Morgan, George B.; Cesare, Bernardo; Buick, Ian; Hermann, Jörg; Bartoli, Omar

    2017-08-01

    We explore the controls, mechanisms and timing of generation of primary melts and their compositions, and show that the novel studies of melt inclusions in migmatites can provide important insights into the processes of crustal anatexis of a particular rock. Partial melting in the source region of granites is dependent on five main processes: (i) supply of heat; (ii) mineral-melt interface reactions associated with the detachment and supply of mineral components to the melt, (iii) diffusion in the melt, (iv) diffusion in minerals, and (v) recrystallization of minerals. As the kinetics of these several processes vary over several orders of magnitude, it is essential to evaluate in Nature which of these processes control the rate of melting, the composition of melts, and the extent to which residue-melt chemical equilibrium is attained under different circumstances. To shed light on these issues, we combine data from experimental and melt inclusion studies. First, data from an extensive experimental program on the kinetics of melting of crustal protoliths and diffusion in granite melt are used to set up the necessary framework that describes how primary melt compositions are established during crustal anatexis. Then, we use this reference frame and compare compositional trends from experiments with the composition of melt inclusions analyzed in particular migmatites. We show that, for the case of El Hoyazo anatectic enclaves in lavas, the composition of glassy melt inclusions provides important information on the nature and mechanisms of anatexis during the prograde suprasolidus history of these rocks, including melting temperatures and reactions, and extent of melt interconnection, melt homogenization and melt-residue equilibrium. Compositional trends in several of the rehomogenized melt inclusions in garnet from migmatites/granulites in anatectic terranes are consistent with diffusion in melt-controlled melting, though trace element compositions of melt inclusions

  7. Crustal and Lithospheric Structure of the Western Mediterranean: Pds Receiver Function Results from the PICASSO Experiment

    Science.gov (United States)

    Thurner, S.; Palomeras, I.; Levander, A.

    2012-12-01

    The Betic Mountains in southern Spain, the Gibraltar Arc, the Alboran Sea, and the Rif and Atlas Mountains in northern Africa comprise the western Mediterranean tectonic region, which has been affected by simultaneous extension and compression throughout the Cenozoic. Multiple geodynamic models have been invoked to explain the coeval compressional and extensional tectonic processes, including slab roll-back (Royden, 1993; Lonergan and White, 1997; Gutscher et al., 2002), accompanied and followed by lithospheric convective downwelling (Seber et al., 1996; Calvert et al., 2000), and delamination (Platt et al., 1996). We use Ps teleseismic receiver functions to investigate the crustal and lithospheric structure throughout this region. PICASSO (Program to Investigate Convective Alboran Sea System Overturn) is a multi-disciplinary, international investigation seeking to improve our understanding of the geodynamics of the western Mediterranean. The PICASSO deployment includes 89 broadband stations distributed linearly from central Spain to the Morocco-Algeria border. For this study we supplemented the PICASSO dataset with data from six other Moroccan, Spanish, Portuguese, and German networks in the region. Using 167 events (M > 6.0) recorded at a total of 240 stations we calculated 1 Hz and 2Hz receiver functions. The receiver functions were then CCP stacked to create a 3D image volume of the region. The Pds receiver functions indicate crustal thicknesses between ~42-47 km in southern Spain beneath the Betic Mountains and ~35-45 km across the Gibraltar Strait. Beneath both the Rif and Betic Mountains we observe complex crustal structures, including two strong positive arrivals around Moho depth (~50 km). A number of models can explain this feature, including those associated thrust systems in each region. In Morocco, along a NW-SE transect from the Gibraltar Strait across the Atlas Mountains, we observe thick crust in the north beneath the Rif Mountains and to the south

  8. Constraints on crustal structure in the Southeastern United States from the SUGAR 2 refraction seismic refraction experiment

    Science.gov (United States)

    Marzen, R. E.; Shillington, D. J.; Lizarralde, D.; Harder, S. H.

    2016-12-01

    The Southeastern United States is an ideal location to study the interactions between continental collision, extensive but short-lived magmatism, and continental rifting. Continental collision during the Alleghenian Orogeny ( 290 Ma) formed the supercontinent Pangea. Extension leading to the breakup of Pangea began 230 Ma, forming the South Georgia Basin and other rift basins. The extensive Central Atlantic Magmatic Province (CAMP) magmatism was emplaced at 200 Ma, and continental separation occurred afterwards. During these processes, part of the African continent was added to North America. Prior work has raised questions including (1) the location and geometry of the suture zone and implications for the style of collision (thin-skinned versus thick-skinned), (2) the role of pre-existing structures on later rifting, and (3) the distribution of magmatism, and possible relationships between magmatism and rifting. To address these questions, we present preliminary velocity models for the 400-km-long refraction seismic line from the SUwanee Suture and GA Rift basin experiment (SUGAR) Line 2. This line is central to CAMP magmatism, and crosses the South Georgia rift basin and two hypothesized locations for the ancient suture zone. The data were collected in August 2015 by a team of over 40 students and scientists. Fifteen shots spaced at 20-40 km were recorded by 1981 Texans spaced at 250 m. We observe refractions from the basin, crust, and upper mantle, and wide-angle reflections from the base of the sediments, within the crust, and from the Moho. Prominent mid crustal reflections may arise from the top of elevated lower crustal velocities and possible lower crustal layering. The starting velocity model and constraints on the upper sedimentary basin velocity structure are obtained through forward modeling, which show basin sediment thickness increasing to the South. We then invert for smooth 2D velocity structure using first arrivals (FAST) and a layered velocity

  9. Shallow Crustal Structure in Northern Taiwan from the TAIGER Active-Source Experiment

    Science.gov (United States)

    Lin, Y.-P.; Zhao, L.; Hung, S.-H.

    2012-04-01

    To study the structures beneath the Taiwan Island and off-shore region, the TAiwan Integrated GEodynamics Research (TAIGER) project conducted a series of geophysical explorations, one of which involves 10 land explosions in 2008 along two east-west transects in northern and southern Taiwan. These valuable high-quality ground-truth observations greatly enhanced our capability to investigate the crustal velocity structure beneath Taiwan. In this study, we manually obtained the first-arrival times in the records collected from the 5 explosions in the northern transect to 551 stations densely-deployed in northern Taiwan. With a trial-and-error procedure, we fit the first-arrival times based on ray tracing and obtained 2D models along a number of shot-station profiles, which showed remarkable consistency with the well-established tectonic divisions in Taiwan. Based on the collection of 2D models, we then conducted an inversion for the 3D structure using the partition modelling approach of Bodin et al. (2009). The study area is partitioned into a number of randomly generated horizontal polygons defined by Voronoi tessellation cells. The velocity in each cell was determined by the 2D models already obtained from forward modelling. A stable inversion result was achieved through the ensemble average of a multitude of partition modeling realizations, without the need for explicit regularization in the inversion process. In comparison with existing tomography models for northern Taiwan, our 3D model obtained from the ground-truth first-arrival times provides a much better prediction of waveforms and phase arrival times.

  10. Deep Crustal Seismic Reflection Experiment Across the Sothern Karoo Basin, South Africa

    OpenAIRE

    A. S. Lindeque; Trond Ryberg; Jacek Stankiewicz; Michael Weber; M. J. de Wit

    2007-01-01

    A controlled source Near Vertical Reflection (NVR) Seismic experiment along a ~ 100 km profile yields the first high quality seismic image of the crust and Moho across the southern Karoo Basin in South Africa. The highly reflective crust comprises upper, middle and lower layers. In the upper crust, folded and gently south-dipping continuous reflectors up to the Escarpment, represent the bedding of the Karoo and Cape Supergroups respectively. Décollement structures occur locally along carbona...

  11. Surgical treatment of organising pneumonia mimicking lung cancer: experience of 27 patients.

    Science.gov (United States)

    Wu, Chen-Tu; Chang, Yih-Leong; Chen, Wei-Chou; Lee, Yung-Chie

    2010-04-01

    Organising pneumonia as a localised process has sometimes been managed by surgery. This poorly defined entity has been mistaken clinically, roentgenographically and usually at exploratory thoracotomy for lung cancer. This series details our experiences with surgical resections in 27 patients during the past 13 years. Surgical lung resection was performed through wedge resection or lobectomy with or without video-assisted thoracoscopic surgery. Resected specimens were swabbed for aerobic and anaerobic bacterial, fungal and mycobacterial cultures. Clinical presentation, roentgenological examination, location and size of the tumourous lesions, pathological finding and treatment were investigated. The patients were between 41 and 80 years of age. Most of the patients (81.5%) presented with cough, haemoptysis and weight loss. The common radiographic findings were round or oval mass with occasionally air bronchogram. Thirteen patients underwent non-invasive biopsy without conclusive diagnosis. The tumour size ranged from 1.5 cm to 8.5 cm. The typically grossly involved area was sharply outlined, firm and extended to the pleura, which was invariably thickened. The microscopic pattern was also rather similar, with inflammation in various degrees of organisation, sometimes accompanied by necrotising changes in the bronchi. Viridans Streptococci and Neisseria spp. were identified as the aetiologic agents in 15 cases (55.6%). All patients had an excellent outcome. The usual investigative procedures for pulmonary mass were of little aid in establishing the differential diagnosis of organising pneumonia from neoplasm. Surgical resection should be considered in the absence of a positive diagnosis of a persistent pulmonary mass. Copyright (c) 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

  12. Mimicking pestcide percolation dynamics in ditches bed by successive column infltration experiment

    Science.gov (United States)

    Dages, Cecile; Samouelian, Anatja; Storck, Veronika; Negro, Sandrine; Huttel, Olivier; Voltz, Marc

    2014-05-01

    Soil layers underlying ditch beds acquire specific characteristics due to ii) hydrological and erosion/deposition processes occurring within the ditch and ii) management practices (burning, dredging, mowing, …). For example, organic matter contents of the ditch beds can be larger than those in neighboring fields, since ditches act as buffer zones. Besides, in Mediterranean catchments, farmed ditches are known to be zones of groundwater recharge and thereby may contribute to groundwater pollution. The role of farmed ditches in groundwater contamination needs therefore to be clarified. The purpose of this study was to determine the dynamic of pesticide percolation in infiltrating farmed ditches bed during a sequence of flood events. A complementary aim was to determine to which extent pesticide percolation from the ditches is correlated to surface flow water contamination. A succession of 9 flood simulations were performed on an undisturbed soil column sampled in the a ditch of the Roujan catchment (Hérault, France), which belongs to the long term Mediterranean hydrological observatory OMERE (Voltz and Albergel, 2002). The soil column was 15 cm long with a 15 cm inner-diameter. For the first 5 flood simulations, injected water was doped with 14C-diuron, an herbicide used in vineyards; uncontaminated water was injected for the last 4 simulations. Free drainage was imposed at the bottom of the column. Diuron concentration was kept constant during a simulated infiltration experiment, but it was progressively decreased from 1000 to 0 µg/L along the succession of the 9 events to mimic the observed seasonal variation of mean diuron concentration in surface flow at the study site (Louchart et al., 2001). Additionally, the first flood simulation was performed with tritium water to assess references on conservative transport within the soil column. For each simulation, the inflow and outflow hydrogram and chemogram were monitored. Extractable (water and solvent) and non

  13. Crustal permeability

    Science.gov (United States)

    Gleeson, Tom; Ingebritsen, Steven E.

    2016-01-01

    Permeability is the primary control on fluid flow in the Earth’s crust and is key to a surprisingly wide range of geological processes, because it controls the advection of heat and solutes and the generation of anomalous pore pressures.  The practical importance of permeability – and the potential for large, dynamic changes in permeability – is highlighted by ongoing issues associated with hydraulic fracturing for hydrocarbon production (“fracking”), enhanced geothermal systems, and geologic carbon sequestration.  Although there are thousands of research papers on crustal permeability, this is the first book-length treatment.  This book bridges the historical dichotomy between the hydrogeologic perspective of permeability as a static material property and the perspective of other Earth scientists who have long recognized permeability as a dynamic parameter that changes in response to tectonism, fluid production, and geochemical reactions. 

  14. Mimicking titration experiments with MD simulations: A protocol for the investigation of pH-dependent effects on proteins

    Science.gov (United States)

    Socher, Eileen; Sticht, Heinrich

    2016-03-01

    Protein structure and function are highly dependent on the environmental pH. However, the temporal or spatial resolution of experimental approaches hampers direct observation of pH-induced conformational changes at the atomic level. Molecular dynamics (MD) simulation strategies (e.g. constant pH MD) have been developed to bridge this gap. However, one frequent problem is the sampling of unrealistic conformations, which may also lead to poor pKa predictions. To address this problem, we have developed and benchmarked the pH-titration MD (pHtMD) approach, which is inspired by wet-lab titration experiments. We give several examples how the pHtMD protocol can be applied for pKa calculation including peptide systems, Staphylococcus nuclease (SNase), and the chaperone HdeA. For HdeA, pHtMD is also capable of monitoring pH-dependent dimer dissociation in accordance with experiments. We conclude that pHtMD represents a versatile tool for pKa value calculation and simulation of pH-dependent effects in proteins.

  15. The crustal structures from Wuyi-Yunkai orogen to Taiwan orogen: the onshore-offshore wide-angle seismic experiment of TAIGER and ATSEE projects

    Science.gov (United States)

    Kuochen, H.; Kuo, N. Y. W.; Wang, C. Y.; Jin, X.; Cai, H. T.; Lin, J. Y.; Wu, F. T.; Yen, H. Y.; Huang, B. S.; Liang, W. T.; Okaya, D. A.; Brown, L. D.

    2015-12-01

    The crustal structure is key information for understanding the tectonic framework and geological evolution in the southeastern China and its adjacent area. In this study, we integrated the data sets from the TAIGER and ATSEE projects to resolve onshore-offshore deep crustal seismic profiles from the Wuyi-Yunkai orogen to the Taiwan orogen in southeastern China. Totally, there are three seismic profiles resolved and the longest profile is 850 km. Unlike 2D and 3D first arrival travel-time tomography from previous studies, we used both refracted and reflected phases (Pg, Pn, PcP, and PmP) to model the crustal structures and the crustal reflectors. 40 shots, 2 earthquakes, and about 1,950 stations were used and 15,319 arrivals were picked among three transects. As a result, the complex crustal evolution since Paleozoic era are shown, which involved the closed Paleozoic rifted basin in central Fujian, the Cenozoic extension due to South China sea opening beneath the coastline of southern Fujian, and the on-going collision of the Taiwan orogen.

  16. IODP Expedition 301 Installs Three Borehole Crustal Observatories, Prepares for Three-Dimensional, Cross-Hole Experiments in the Northeastern Pacific Ocean

    Directory of Open Access Journals (Sweden)

    Adam Klaus

    2005-09-01

    Full Text Available Introduction and Goals The basaltic upper oceanic crust comprises the largestaquifer on Earth, containing a volume of water about equalto that currently stored in ice sheets and glaciers. Annualfluid fluxes through the upper oceanic crust are at leastas large as the global river flux to the ocean. Much of theseafloor is hydrogeologically active, but the majority ofthe fluid flow within oceanic crust occurs on ridge flanks,regions located kilometers or more from active seafloorspreading centers. Fluid circulation in these areas is drivenmainly by lithospheric heat rising from deep within theplate but is influenced by seafloor and basement topography,seismic and tectonic events, and tides.Subseaf loor f luid f low on ridge f lanks inf luences adiverse array of processes and properties, including thethermal state and evolution of oceanic plates, alteration ofthe lithosphere and crustal pore waters, establishment andmaintenance of vast subseaf loor microbial ecosystems,and diagenetic, seismic, and magmatic activity along plateboundaryfaults. Although numerous drilling expeditionsand surface and submersible surveys over the last severaldecades have focused on hydrogeologic phenomena, we stillknow relatively little about driving forces, property distributions,scales of flow, rates of flow, extent of compartmentalizationor isolation of distinct fluid-rock systems, or linksbetween hydrogeologic, geochemical, microbiological, andgeophysical processes. Progress through drilling has beenlimited in the past by the perturbing effects of boreholecreation on subseafloor thermal, pressure, chemical, andbiological conditions. Subseafloor observatories addressthis challenge by allowing the formation to recover fromdrilling perturbations, and also allow scientists to runpassive and active experiments for years to decades.IODP Expedition 301 was part of a multi-disciplinaryprogram designed to evaluate the formation-scale hydrogeologicproperties within oceanic crust

  17. Modes of continental extension in a crustal wedge

    KAUST Repository

    Wu, Guangliang

    2015-07-01

    © 2015 Elsevier B.V. We ran numerical experiments of the extension of a crustal wedge as an approximation to extension in an orogenic belt or a continental margin. We study the effects of the strength of the lower crust and of a weak mid-crustal shear zone on the resulting extension styles. A weak mid-crustal shear zone effectively decouples upper crustal extension from lower crustal flow. Without the mid-crustal shear zone, the degree of coupling between the upper and the lower crust increases and extension of the whole crust tends to focus on the thickest part of the wedge. We identify three distinct modes of extension determined by the strength of the lower crust, which are characterized by 1) localized, asymmetric crustal exhumation in a single massif when the lower crust is weak, 2) the formation of rolling-hinge normal faults and the exhumation of lower crust in multiple core complexes with an intermediate strength lower crust, and 3) distributed domino faulting over the weak mid-crustal shear zone when the lower crust is strong. A frictionally stronger mid-crustal shear zone does not change the overall model behaviors but extension occurred over multiple rolling-hinges. The 3 modes of extension share characteristics similar to geological models proposed to explain the formation of metamorphic core complexes: 1) the crustal flow model for the weak lower crust, 2) the rolling-hinge and crustal flow models when the lower crust is intermediate and 3) the flexural uplift model when the lower crust is strong. Finally we show that the intensity of decoupling between the far field extension and lower crustal flow driven by the regional pressure gradient in the wedge control the overall style of extension in the models.

  18. Lunar Crustal Stratigraphy

    Science.gov (United States)

    McCallum, I. S.; O'Brien, H. E.

    1996-03-01

    Intense bombardment during the first 600 Ma of lunar history has rendered the task of reconstructing the stratigraphy of the lunar crust especially difficult. On a planetary scale, the distribution of lithologies around multi-ringed basins coupled with orbital geochemical data reveal that the lunar crust is heterogeneous both laterally and vertically. Ejecta from the large multi-ringed basins is exclusively of crustal origin since twenty five years of lunar sample study have failed to identify any unequivocal mantle samples. Given the most recent determination of crustal thickness, this implies an upper limit to the depth of excavation of around 60 km. In the younger multi-ringed basins (Orientale and Imbrium), the occurrence of anorthosites in inner rings is consistent with an anorthositic upper crust (Al2O3 = 26-28 wt.%). On the other hand, basin impact melts, most notably the low-K Fra Mauro (LKFM) composition associated with the Imbrium and Serenitatis basins, are distinctly more mafic with a composition corresponding to norite (Al2O3 ~ 20 wt.%). Cratering models suggest that such melts are generated at the lower to middle crustal depths (30 to 60 km). The paucity of unequivocal deep-seated crystalline plutonic rocks is also consistent with cratering models which suggest that unmelted rock fragments in ejecta blankets are most likely derived from the upper part of the crust. Consequently, the possibility exists that no crystalline lunar samples from deeper that ~30 km are present in the returned sample collection.

  19. Crustal structure beneath the middle-lower Yangtze metallogenic belt in East China: Constraints from passive source seismic experiment on the Mesozoic intra-continental mineralization

    Science.gov (United States)

    Shi, Danian; Lü, Qingtian; Xu, Wenyi; Yan, Jiayong; Zhao, Jinhua; Dong, Shuwen; Chang, Yinfo

    2013-10-01

    To understand the formation and the tectonic process of the Mesozoic middle-lower Yangtze metallogenic belt (YMB), the SinoProbe program deployed a quasi-linear passive source seismic array across the belt. We performed receiver function profiling and measurement of shear-wave splitting parameters with the collected data. Our results show that the Moho depth varies significantly along the profile and that a “mantle uplift” exists right beneath the YMB. We also found that the lower crust of the YMB is different from that of its adjacent areas in structure on the receiver function profile. It possesses seismic anisotropy with direction roughly parallel to the belt. Our SKS/SKKS shear-wave splitting results also show similar belt-parallel azimuthal anisotropy right beneath the YMB. We interpret the seismic anisotropy in the lower crust of the YMB as the result of mineral crystal alignment caused by melting and belt-parallel flow in the Mesozoic ore-forming process. Besides, we observed a nearly south-dipping converter extending from shallow to lower crust beneath the Hefei Basin, which most possibly resulted from the Mesozoic crustal extension. We interpret the “mantle uplift” and the crustal extensional structures to be consequences of asthenospheric upwelling during the Mesozoic ore-forming process. Our results suggest that the lower crust of the YMB was most likely one part of the multi-level metallogenic magma system in the Mesozoic magmatism and mineralization processes, and the formation of the metallogenic belt to be a result much similar to the MASH (Melting, Assimilation, Storage and Homogenization; cf. Hildreth and Moorbath, 1988; Richards, 2003) process. First, the asthenospheric upwelling resulted in a crustal extensional environment; then the melts from the upwelling asthenosphere intruded into the lower crust of the YMB, and assimilation occurred when they mixed with in situ lower crustal materials, which led to the formation of adakitic

  20. Urticaria mimickers in children.

    Science.gov (United States)

    Mathur, Anubhav N; Mathes, Erin F

    2013-01-01

    Acute urticaria is a self-limited cutaneous condition marked by transient, erythematous, and pruritic wheals. It is a hypersensitivity response that is often secondary to infection, medications, or food allergies in children. In contrast, the urticarial "mimickers" described in this review article are often seen in the context of fever and extracutaneous manifestations in pediatric patients. The differential diagnosis ranges from benign and self-limited hypersensitivity responses to multisystem inflammatory diseases. Establishing the correct diagnosis of an urticarial rash in a pediatric patient is necessary to both prevent an unnecessary work up for self-limited conditions and to appropriately recognize and evaluate multisystem inflammatory disorders. Herein, we describe two cases to illustrate the clinical manifestations, laboratory findings, histopathology and differential diagnoses for several mimickers of acute urticaria including: urticaria multiforme, serum sickness like reaction, Henoch-Schönlein purpura, acute hemorrhagic edema of infancy, systemic onset juvenile idiopathic arthritis, cryopyrin associated periodic syndromes, and urticarial vasculitis. © 2013 Wiley Periodicals, Inc.

  1. A three-dimensional Vp, Vs, and Vp/Vs crustal structure in Fujian, Southeast China, from active- and passive-source experiments

    Science.gov (United States)

    Cai, Hui-Teng; Kuo-Chen, Hao; Jin, Xin; Wang, Chien-Ying; Huang, Bor-Shouh; Yen, Horng-Yuan

    2015-11-01

    Fujian, Southeastern China, has experienced multistage tectonic activities since the Neoproterozoic Era and is currently influenced by collision between the Eurasian and Philippine Sea plates. Topography, fault zones, and patterns of seismicity are the imprints of tectonic evolution. Historically, there have been several catastrophic earthquakes in the southeastern part of Fujian. To understand the crustal structure related to the fault zones, we performed Vp, Vs, and Vp/Vs travel-time tomography using joint inversion of active and passive sources. A total of 75,827 and 31,044 arrivals of P and S waves, respectively, from 33 explosions and 2543 earthquakes are used in our study. As a result, seismicity has indicated that two NE strike seismogenic zones, the Zhenghe-Dapu and Changle-Zhaoan fault zones, are currently active. Low Vp/Vs ratios in inland Fujian imply that the crust is mainly composed of felsic rocks as part of the Eurasian continental crust, which is consistent with geological observations at the surface. Based on Vp tomography, the thickness of the crust along the coastline is shallower than that on land, which is related to higher heat flow and the Bouguer anomaly. This shallow crust phenomenon near the coastline could be related to the regional extensional stress: the remaining structure of the back-arc extension that stretched the continental crust during the Mesozoic Era or/and the Cenozoic extension due to South China sea opening in Taiwan Strait.

  2. Crustal thickness controlled by plate tectonics

    DEFF Research Database (Denmark)

    Artemieva, Irina M.; Meissner, Rolf

    2012-01-01

    /gabbro–eclogite phase transition in crustal evolution and the links between lithosphere recycling, mafic magmatism, and crustal underplating. We advocate that plate tectonics processes, togetherwith basalt/gabbro–eclogite transition, limit crustal thickness worldwide by providing effective mechanisms of crustal...

  3. Detailed crustal thickness variations beneath the Illinois Basin area: Implications for crustal evolution of the midcontinent

    Science.gov (United States)

    Yang, Xiaotao; Pavlis, Gary L.; Hamburger, Michael W.; Marshak, Stephen; Gilbert, Hersh; Rupp, John; Larson, Timothy H.; Chen, Chen; Carpenter, N. Seth

    2017-08-01

    We present high-resolution imaging results of crustal and upper mantle velocity discontinuities across the Illinois Basin area using both common conversion point stacking and plane wave migration methods applied to P wave receiver functions from the EarthScope Ozark, Illinois, Indiana, and Kentucky experiment. The images reveal unusually thick crust (up to 62 km) throughout the central and southeastern Illinois Basin area. A significant Moho gradient underlies the NW trending Ste. Genevieve Fault Zone, which delineates the boundary between the Illinois Basin and Ozark Dome. Relatively thinner crust (Proterozoic convergent margin tectonics around 1.55-1.35 Ga; (3) by Late Precambrian magmatic underplating at the base of older crust, associated with the creation of the Eastern Granite-Rhyolite Province around 1.3 Ga; and (4) through crustal "relamination" during an episode of Proterozoic flat-slab subduction beneath the Illinois Basin, possibly associated with the Grenville Orogeny.

  4. Analogue experiment of the crustal deformation by X-ray CT; X sen CT wo mochiita chikaku no henkei no analogue jikken

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Y.; Shi, B; Murakami, Y. [Geological Survey of Japan, Tsukuba (Japan)

    1997-05-27

    This paper reports a predictive result on a deformation experiment on sand beds using an X-ray computerized tomography (CT) equipment. The X-ray CT is a method to perform the following processes: X-rays are irradiated on a sample; decayed intensity data are measured along ray paths of the permeated X-rays; the data are inverted by using the Fourier transform; and spatial distribution of the coefficient of X-ray absorption inside the sample is acquired as a gray scale image. The deformation experiment was carried by putting sand into an acrylic container to a depth of 2 cm and manually pressing a plate in the horizontal direction. Sand blocks make a relative motion along a specific plane when they are deformed, but it was not possible to recognize faults clearly by naked eyes. Upon completion of the deformation, the experimental device was placed on the CT equipment to acquire images of the two-dimensional cross section. The higher the X-ray absorption coefficient, the brighter the picture elements. It can be seen that three inversed faults have been imaged clearly. Therefore, this equipment was verified usable as an effective observation equipment for an analogue deformation experiment. 4 refs., 2 figs.

  5. Crustal Ages of the Ocean Floor - Poster

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Crustal Ages of the Ocean Floor Poster was created at NGDC using the Crustal Ages of the Ocean Floor database draped digitally over a relief of the ocean floor...

  6. Hypothyroid myopathy mimicking postpolio syndrome.

    Science.gov (United States)

    Verma, Rajesh; Lalla, Rakesh; Sahu, Ritesh

    2012-08-24

    Hypothyroidism can have diverse neurological manifestations. Myopathy may rarely be the sole manifestation of autoimmune thyroiditis. We hereby report an atypical manifestation of severe hypothyroidism in a middle-aged woman with childhood onset of paralytic polio involving her right leg presenting with a recent onset of increased weakness in the right leg mimicking postpolio syndrome.

  7. Crustal structure beneath Eastern Greenland

    DEFF Research Database (Denmark)

    Reiche, Sönke; Thybo, H.; Kaip, G.

    2011-01-01

    The conjugate Atlantic passive margins of western Norway and eastern Greenland are characterized by the presence of coast-parallel mountain ranges with peak elevations of more than 3.5 km close to Scoresby Sund in Eastern Greenland. Knowledge about crustal thickness and composition below these mo...

  8. Combined crustal-geological cross-section of Ellesmere Island

    DEFF Research Database (Denmark)

    Stephenson, Randell Alexander; Schiffer, Christian; Oakey, Gordon

    Ellesmere Island, in Canada’s Arctic, consists of a series of ~SW-NE trending tectonic provinces, the crustal structure and geological expression of which represent a combination of interplate, accretionary orogenesis in the Palaeozoic and, most recently, intraplate deformation in the Cenozoic...... (Eurekan “Orogeny”). An almost complete absence of information about the crustal or lithosphere structure of Ellesmere Island has been addressed by the acquisition of teleseismic data between 2010 and 2012 on a passive seismological array called ELLITE (“Ellesmere Island Teleseismic Experiment......”). The ELLITE array consisted of seven broadband stations, deployed for two years on a 520 km long, N-S orientated profile and was logistically supported by the GSC (Canada) and SEIS-UK. Extracted Receiver Functions (RFs) and a resulting composite two-dimensional crustal scale cross-section of Ellesmere Island...

  9. Multicystic Hepatocarcinoma Mimicking Liver Abscess

    Directory of Open Access Journals (Sweden)

    Evangelos Falidas

    2013-01-01

    Full Text Available The diagnosis of hepatocellular carcinoma (HCC became easier in relation to the improved radiological examinations; however, the neoplasm may occur under atypical presentations mimicking other benign or malignant processes. Multicystic HCC mimicking a liver abscess associated with septic-type fever and leukocytosis is rare, has a poor prognosis, and poses diagnostic and therapeutic dilemmas. We present the case of an 80-year-old patient, who presented with fever, leukocytosis, and large cystic masses involving right and left lobes of the liver initially considered abscesses and finally diagnosed as HCC after open drainage and liver biopsy. Although the patient died on the tenth postoperative day due to pulmonary oedema, the authors emphasize the high index of suspicion needed in the diagnosis of this unusual presentation of HCC.

  10. Propionic acidemia mimicking diabetic ketoacidosis.

    Science.gov (United States)

    Dweikat, Imad M; Naser, Enas N; Abu Libdeh, Abdulsalam I; Naser, Osama J; Abu Gharbieh, Najwan N; Maraqa, Nizar F; Abu Libdeh, Bassam Y

    2011-05-01

    Propionic acidemia manifesting with hyperglycemia is rare. Few cases have been reported mainly of the neonatal-onset form associated with high mortality. We report a 9-month-old Palestinian boy who manifested with coma, severe hyperglycemia and ketoacidosis mimicking diabetic ketoacidosis. Family history of unexplained infant deaths was helpful in reaching the correct diagnosis. In response to therapy, the patient regained consciousness without neurologic deficits and had normal examination. This is, to our knowledge, the first case report of late-onset propionic acidemia that had this presentation and survived. Copyright © 2010 The Japanese Society of Child Neurology. All rights reserved.

  11. Ocular Argyrosis Mimicking Conjunctival Melanoma.

    Science.gov (United States)

    Tendler, Irwin; Pulitzer, Melissa P; Roggli, Victor; Abramson, David H; Marr, Brian P

    2017-06-01

    To present a novel case of ocular argyrosis mimicking conjunctival melanoma. A 48-year-old man who is a jewelry manufacturer presented with raised pigmented lesions in the inferior fornices of both eyes. Brown-black colored, follicle-like, masses were observed in both fornices. An incisional biopsy confirmed the presence of silver and the diagnosis of ocular argyrosis. Despite its limited negative health effects, ocular argyrosis should be considered in the differential diagnosis of conjunctival pigmented lesions because of the potential for misidentification of neoplastic growth.

  12. Oral candidiasis mimicking tongue cancer.

    Science.gov (United States)

    Shibata, Tomohisa; Yamashita, Daisuke; Hasegawa, Shingo; Saito, Miki; Otsuki, Naoki; Hashikawa, Kazunobu; Tahara, Shinya; Nibu, Ken-ichi

    2011-06-01

    Candida species inhabit the mucosal surfaces of healthy individuals. Major forms of oral candidiasis are pseudomembranous and atrophic form, but chronic hyperplastic candidiasis (CHC) is rarely seen. We encountered a nodule caused by candidal infection on a forearm flap in the oral cavity mimicking a recurrent tongue cancer, which revealed as CHC by histopathological examination. Like other forms of oral candidiasis, the nodule well responded to the treatment of antifungal agents and eventually disappeared. When an intraoral nodule is observed, the possibility of CHC should be taken into consideration. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  13. Crustal structure of Central Sicily

    Science.gov (United States)

    Giustiniani, Michela; Tinivella, Umberta; Nicolich, Rinaldo

    2018-01-01

    We processed crustal seismic profile SIRIPRO, acquired across Central Sicily. To improve the seismic image we utilized the wave equation datuming technique, a process of upward or downward continuation of the wave-field between two arbitrarily shaped surfaces. Wave equation datuming was applied to move shots and receivers to a given datum plane, removing time shifts related to topography and to near-surface velocity variations. The datuming procedure largely contributed to attenuate ground roll, enhance higher frequencies, increase resolution and improve the signal/noise ratio. Processed data allow recognizing geometries of crust structures differentiating seismic facies and offering a direct image of ongoing tectonic setting within variable lithologies characterizing the crust of Central Sicily. Migrated sections underline distinctive features of Hyblean Plateau foreland and above all a crustal thinning towards the Caltanissetta trough, to the contact with a likely deep Permo-Triassic rifted basin or rather a zone of a continent to oceanic transition. Inhomogeneity and fragmentation of Sicily crust, with a distinct separation of Central Sicily basin from western and eastern blocks, appear to have guided the tectonic transport inside the Caltanissetta crustal scale syncline and the accumulation of allochthonous terrains with south and north-verging thrusts. Major tectonic stack operated on the construction of a wide anticline of the Maghrebian chain in northern Sicily. Sequential south-verging imbrications of deep elements forming the anticline core denote a crust wedge indenting foreland structures. Deformation processes involved multiple detachment planes down to decoupling levels located near crust/mantle transition, supporting a presence of high-density lenses beneath the chain, interrelated to a southwards push of Tyrrhenian mantle and asthenosphere.

  14. Gravity Constraints On The Crustal Structure of Northern Tunisia

    Science.gov (United States)

    Jallouli, Chokri; Mickus, Kevin L.; Turki, Mohamed M.

    Bouguer gravity data were analyzed to determine the general crustal and upper mantle structure in northern Tunisia. Residual gravity anomalies were determined by removing the gravitational effect of crustal thickness variations imaged by regional seismic experiments. Residual gravity anomalies contain short wavelength anomalies superimposed on a long wavelength component that decreases in amplitude northward towards the Tunisian coastline. An edge enhancement analysis (e.g., enhanced analytic signals) of the short wavelength anomalies suggests a previously unknown east-west trending gravity anomaly south of 37°N with source depths between 3 and 7 km. Modeling of the regional, residual and Bouguer gravity anomalies indicate there are two possible solutions for the residual gravity decreasing in northern Tunisia: 1) thickening of Cenozoic and Mesozoic sediments north of a strike-slip faults or 2) a crustal and upper mantle low density zone interpreted to be crustal material of the remnant subducted African plate. The latter result is favored based on seismic tomographic images of the Mediterranean region which implies subducting material exists under the African coast, geologic interpretations suggesting the Tell Atlas may be a thrust wedge accreted by underplating of the African continental crust and seismic refraction models indicating a thinning of sediments in northern Tunisia. The east-west trending gravity anomalies south of 37°N corresponds to an important structural feature that could be either a strike slip/transform fault or the northern edge the African plate.

  15. Crustal Deformation In Northeastern Italy.

    Science.gov (United States)

    Zerbini, S.; Romagnoli, C.; Richter, B.; Lago, L.; Domenichini, F.; Simon, D.

    Four permanent GPS stations have been installed in northeastern Italy starting mid 1996. Three stations: Bologna, Medicina and Porto Corsini are located in the south- eastern Po Plain, while the fourth one was set up in the Trieste harbor. The network was installed to monitor vertical crustal movements at tide gauge sites and in sub- siding areas of the Po Plain. At Medicina, since October 1996, it is also operative a superconducting gravimeter periodically controlled by means of absolute gravity mea- surements. The stations, which are distributed around the northern edge of the Adria plate, provide information on vertical and horizontal displacements related to crustal deformation. The temporal behavior of the Adria plate, in response to the convergence of the surrounding regions, has been presumably more complex than a simple horizon- tal displacement and, most likely, involved flexural bending processes. The GPS and the continuous gravity data have been analyzed and interpreted to estimate vertical and horizontal rates at the four sites. The presence of relevant seasonal signals has been identified in the series of station coordinates as well as in the gravity data. These fluc- tuations, if not accounted for, may corrupt the high precision estimate of the long-term trends.

  16. Sensing the earth crustal deformation with nano-strain resolution fiber-optic sensors.

    Science.gov (United States)

    Liu, Qingwen; He, Zuyuan; Tokunaga, Tomochika

    2015-06-01

    Crustal deformation measurement with a high resolution on the order of nano-strains in static to low frequency region is required for geophysical research. Optical fiber sensors are very attractive in this research field due to their unique advantages including high resolution, small size and easy deployment. In this paper, a fiber optic strain sensor with nano-strain-resolution and large measurement range for sensing the earth crustal deformation is reported. With this sensor the tide induced crustal deformation and the seismic wave were successfully recorded in field experiments.

  17. Seismic velocity and crustal thickness inversions: Moon and Mars

    Science.gov (United States)

    Drilleau, Melanie; Blanchette-Guertin, Jean-François; Kawamura, Taichi; Lognonné, Philippe; Wieczorek, Mark

    2017-04-01

    We present results from new inversions of seismic data arrival times acquired by the Apollo active and passive experiments. Markov chain Monte Carlo inversions are used to constrain (i) 1-D lunar crustal and upper mantle velocity models and (ii) 3-D lateral crustal thickness models under the Apollo stations and the artificial and natural impact sites. A full 3-D model of the lunar crustal thickness is then obtained using the GRAIL gravimetric data, anchored by the crustal thicknesses under each Apollo station and impact site. To avoid the use of any seismic reference model, a Bayesian inversion technique is implemented. The advantage of such an approach is to obtain robust probability density functions of interior structure parameters governed by uncertainties on the seismic data arrival times. 1-D seismic velocities are parameterized using C1-Bézier curves, which allow the exploration of both smoothly varying models and first-order discontinuities. The parameters of the inversion include the seismic velocities of P and S waves as a function of depth, the thickness of the crust under each Apollo station and impact epicentre. The forward problem consists in a ray tracing method enabling both the relocation of the natural impact epicenters, and the computation of time corrections associated to the surface topography and the crustal thickness variations under the stations and impact sites. The results show geology-related differences between the different sites, which are due to contrasts in megaregolith thickness and to shallow subsurface composition and structure. Some of the finer structural elements might be difficult to constrain and might fall within the uncertainties of the dataset. However, we use the more precise LROC-located epicentral locations for the lunar modules and Saturn-IV upper stage artificial impacts, reducing some of the uncertainties observed in past studies. In the framework of the NASA InSight/SEIS mission to Mars, the method developed in

  18. Bimodal magmatism produced by progressively inhibited crustal assimilation.

    Science.gov (United States)

    Meade, F C; Troll, V R; Ellam, R M; Freda, C; Font, L; Donaldson, C H; Klonowska, I

    2014-06-20

    The origin of bimodal (mafic-felsic) rock suites is a fundamental question in volcanology. Here we use major and trace elements, high-resolution Sr, Nd and Pb isotope analyses, experimental petrology and thermodynamic modelling to investigate bimodal magmatism at the iconic Carlingford Igneous Centre, Ireland. We show that early microgranites are the result of extensive assimilation of trace element-enriched partial melts of local metasiltstones into mafic parent magmas. Melting experiments reveal the crust is very fusible, but thermodynamic modelling indicates repeated heating events rapidly lower its melt-production capacity. Granite generation ceased once enriched partial melts could no longer form and subsequent magmatism incorporated less fertile restite compositions only, producing mafic intrusions and a pronounced compositional gap. Considering the frequency of bimodal magma suites in the North Atlantic Igneous Province, and the ubiquity of suitable crustal compositions, we propose 'progressively inhibited crustal assimilation' (PICA) as a major cause of bimodality in continental volcanism.

  19. Bimodal magmatism produced by progressively inhibited crustal assimilation

    Science.gov (United States)

    Meade, F. C.; Troll, V. R.; Ellam, R. M.; Freda, C.; Font, L.; Donaldson, C. H.; Klonowska, I.

    2014-06-01

    The origin of bimodal (mafic-felsic) rock suites is a fundamental question in volcanology. Here we use major and trace elements, high-resolution Sr, Nd and Pb isotope analyses, experimental petrology and thermodynamic modelling to investigate bimodal magmatism at the iconic Carlingford Igneous Centre, Ireland. We show that early microgranites are the result of extensive assimilation of trace element-enriched partial melts of local metasiltstones into mafic parent magmas. Melting experiments reveal the crust is very fusible, but thermodynamic modelling indicates repeated heating events rapidly lower its melt-production capacity. Granite generation ceased once enriched partial melts could no longer form and subsequent magmatism incorporated less fertile restite compositions only, producing mafic intrusions and a pronounced compositional gap. Considering the frequency of bimodal magma suites in the North Atlantic Igneous Province, and the ubiquity of suitable crustal compositions, we propose ‘progressively inhibited crustal assimilation’ (PICA) as a major cause of bimodality in continental volcanism.

  20. Tracheobronchial Amyloidosis Mimicking Tracheal Tumor

    Directory of Open Access Journals (Sweden)

    Elif Tanrıverdi

    2016-01-01

    Full Text Available Tracheobronchial amyloidosis is a rare presentation and accounts for about 1% of benign tumors in this area. The diagnosis of disease is delayed due to nonspecific pulmonary symptoms. Therapeutic approaches are required to control progressive pulmonary symptoms for most of the patients. Herein, we report a case of a 68-year-old man admitted with progressive dyspnea to our institution for further evaluation and management. He was initially diagnosed with and underwent management for bronchial asthma for two years but had persistent symptoms despite optimal medical therapy. Pulmonary computed tomography scan revealed severe endotracheal stenosis. Bronchoscopy was performed and showed endotracheal mass obstructing 70% of the distal trachea and mimicking a neoplastic lesion. The mass was successfully resected by mechanical resection, argon plasma coagulation (APC, and Nd-YAG laser during rigid bronchoscopy. Biopsy materials showed deposits of amorphous material by hematoxylin and eosin staining and these deposits were selectively stained with Congo Red. Although this is a rare clinical condition, this case indicated that carrying out a bronchoscopy in any patient complaining of atypical bronchial symptoms or with uncontrolled asthma is very important.

  1. Humanlike Robots - Synthetically Mimicking Humans

    Science.gov (United States)

    Bar-Cohen, Yoseph

    2012-01-01

    Nature inspired many inventions and the field of technology that is based on the mimicking or inspiration of nature is widely known as Biomimetics and it is increasingly leading to many new capabilities. There are numerous examples of biomimetic successes including the copying of fins for swimming, and the inspiration of the insects and birds flight. More and more commercial implementations of biomimetics are appearing and behaving lifelike and applications are emerging that are important to our daily life. Making humanlike robots is the ultimate challenge to biomimetics and, for many years, it was considered science fiction, but such robots are becoming an engineering reality. Advances in producing such robot are allowing them to perform impressive functions and tasks. The development of such robots involves addressing many challenges and is raising concerns that are related to fear of their application implications and potential ethical issues. In this paper, the state-of-the-art of humanlike robots, potential applications and challenges will be reviewed.

  2. Liver actinomycosis mimicking liver tumor

    Directory of Open Access Journals (Sweden)

    Ćulafić Đorđe M.

    2009-01-01

    Full Text Available Background. The liver actinomycosis is a rare disease associated with complex differentiation from the liver metastases or hepatocellular carcinoma. Case report. A 50-year old immunocompetent female patient was admitted to the Surgical Department in an exhausted condition, with dyspnea, significant weight loss and intermittent fever in the recent two months. Diagnostic procedures that followed, including abdominal ultrasound and computed tomography led us to the diagnosis of metastatic liver disease of unknown etiology with pleural and pericardial effusion. Intraoperatively, the presence of liver pseudotumor without malignancy in the liver was confirmed. Histological examination confirmed the diagnosis of liver actinomycosis. Prolonged treatment with high dose penicillin was performed and all signs and symptoms resolved completely without further problems. The control abdominal ultrasound finding was normal. Conclusion. Liver actinomycosis has a nonspecific presentation, often mimicking liver tumor. A timely diagnosis as well as a combined surgical and antibiotic therapy is necessary in the treatment of patients with primary disease and prevention of complications.

  3. PELVIC HYDATID MIMICKING INGUINAL HERNIA

    Directory of Open Access Journals (Sweden)

    Ashwani Kumar Dalal

    2017-11-01

    Full Text Available PRESENTATION OF CASE The classical finding in hydatid disease caused by Echinococcus granulosus with liver or lung involvement is well known. However, diagnosing hydatid disease at unusual locations maybe challenging even in endemic areas causing diagnostic confusion as primary extrahepatic extrapulmonary hydatid cysts are rare and only a few sporadic cases have been reported. We present a case where a painless progressive cystic swelling was present in left inguinal region with positive cough impulse and irreducibility mimicking an inguinal hernia. CECT was done, which confirmed it to be multiple hydatid cysts. The patient underwent excision of the cysts with mesh repair and left inguinal orchiectomy as the cord structures couldn’t be separated from the cyst wall. Patient was discharged in satisfactory condition on oral antibiotics and albendazole. No recurrence noted on 6 months of follow up. So, a high suspicion for hydatid cyst should be kept in mind especially in endemic areas for any intra-abdominal swelling. The surgeon must keep in mind that this parasitosis can occur even in uncommon locations and therefore it should be regarded as a potentially systemic disease. In these cases, the diagnosis is challenging and can be achieved only through a complete interdisciplinary evaluation clinical, laboratory and radiological data.

  4. Science Academies Refresher Course on Crustal Strength ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 22; Issue 3. Science Academies Refresher Course on Crustal Strength Rheology and Seismicity (CSRS-2017). Information and Announcements Volume 22 Issue 3 March 2017 pp 328-328 ...

  5. Crustal Structure of the Khartoum Basin, Sudan

    Science.gov (United States)

    El Tahir, Nada; Nyblade, Andrew; Julià, Jordi; Durrheim, Raymond

    2017-04-01

    The Khartoum basin is one of several Mesozoic rift basins in Sudan associated with the Central Africa Rift System. Little is known about the deep crustal structure of this basin, and this limited knowledge hampers the development of a more detailed understanding of its origin and evolution. Constraints on crustal structure in Sudan are only available through regional gravity studies and continental-scale tomography models, but these studies have poor resolution in the Khartoum basin. Here, we investigate the crustal structure of the northern part of the Khartoum basin beneath 3 permanent seismic stations in Khartoum, Sudan through the H-k stacking of receiver functions and the joint inversion of receiver functions and Rayleigh-wave group velocities. Our H-k-stacking results indicate that crustal thickness beneath the Khartoum basin ranges between 33 and 37 km, with an average of 35 km and that crustal Vp/Vs ratio ranges from 1.74 to 1.81, with an average of 1.78. These results are consistent with 1D velocity models developed from the joint inversion of receiver functions and Rayleigh-wave group velocities, which display similar estimates for crustal thickness and an average shear-wave velocity of 3.7 km/s for the basin's crust. Our results provide the first seismic estimate of Moho depth for a basin in Sudan and, when compared to average crustal thickness for the unrifted Proterozoic crust in eastern Africa, reveal that at most a few kilometers of crustal thinning has occurred beneath the Khartoum basin.

  6. Seismic evidence for widespread western-US deep-crustal deformation caused by extension

    Science.gov (United States)

    Moschetti, M.P.; Ritzwoller, M.H.; Lin, F.; Yang, Y.

    2010-01-01

    Laboratory experiments have established that many of the materials comprising the Earth are strongly anisotropic in terms of seismic-wave speeds. Observations of azimuthal and radial anisotropy in the upper mantle are attributed to the lattice-preferred orientation of olivine caused by the shear strains associated with deformation, and provide some of the most direct evidence for deformation and flow within the Earths interior. Although observations of crustal radial anisotropy would improve our understanding of crustal deformation and flow patterns resulting from tectonic processes, large-scale observations have been limited to regions of particularly thick crust. Here we show that observations from ambient noise tomography in the western United States reveal strong deep (middle to lower)-crustal radial anisotropy that is confined mainly to the geological provinces that have undergone significant extension during the Cenozoic Era (since 65 Myr ago). The coincidence of crustal radial anisotropy with the extensional provinces of the western United States suggests that the radial anisotropy results from the lattice-preferred orientation of anisotropic crustal minerals caused by extensional deformation. These observations also provide support for the hypothesis that the deep crust within these regions has undergone widespread and relatively uniform strain in response to crustal thinning and extension. ?? 2010 Macmillan Publishers Limited. All rights reserved.

  7. Giant hydronephrosis mimicking progressive malignancy

    Directory of Open Access Journals (Sweden)

    Heidenreich Axel

    2003-10-01

    Full Text Available Abstract Background Cases of giant hydronephroses are rare and usually contain no more than 1–2 litres of fluid in the collecting system. We report a remarkable case of giant hydronephrosis mimicking a progressive malignant abdominal tumour. Case presentation A 78-year-old cachectic woman presented with an enormous abdominal tumour, which, according to the patient, had slowly increased in diameter. Medical history was unremarkable except for a hysterectomy >30 years before. A CT scan revealed a giant cystic tumour filling almost the entire abdominal cavity. It was analysed by two independent radiologists who suspected a tumour originating from the right kidney and additionally a cystic ovarian neoplasm. Subsequently, a diagnostic and therapeutic laparotomy was performed: the tumour presented as a cystic, 35 × 30 × 25 cm expansive structure adhesive to adjacent organs without definite signs of invasive growth. The right renal hilar vessels could finally be identified at its basis. After extirpation another tumourous structure emerged in the pelvis originating from the genital organs and was also resected. The histopathological examination revealed a >15 kg hydronephrotic right kidney, lacking hardly any residual renal cortex parenchyma. The second specimen was identified as an ovary with regressive changes and a large partially calcified cyst. There was no evidence of malignant growth. Conclusion Although both clinical symptoms and the enormous size of the tumour indicated malignant growth, it turned out to be a giant hydronephrosis. Presumably, a chronic obstruction of the distal ureter had caused this extraordinary hydronephrosis. As demonstrated in our case, an accurate diagnosis of giant hydronephrosis remains challenging due to the atrophy of the renal parenchyma associated with chronic obstruction. Therefore, any abdominal cystic mass even in the absence of other evident pathologies should include the differential diagnosis of a

  8. Microbial life in ridge flank crustal fluids.

    Science.gov (United States)

    Huber, Julie A; Johnson, H Paul; Butterfield, David A; Baross, John A

    2006-01-01

    To determine the microbial community diversity within old oceanic crust, a novel sampling strategy was used to collect crustal fluids at Baby Bare Seamount, a 3.5 Ma old outcrop located in the north-east Pacific Ocean on the eastern flank of the Juan de Fuca Ridge. Stainless steel probes were driven directly into the igneous ocean crust to obtain samples of ridge flank crustal fluids. Genetic signatures and enrichment cultures of microorganisms demonstrate that these crustal fluids host a microbial community composed of species indigenous to the subseafloor, including anaerobic thermophiles, and species from other deep-sea habitats, such as seawater and sediments. Evidence using molecular techniques indicates the presence of a relatively small but active microbial population, dominated by bacteria. The microbial community diversity found in the crustal fluids may indicate habitat variability in old oceanic crust, with inputs of nutrients from seawater, sediment pore-water fluids and possibly hydrothermal sources. This report further supports the presence of an indigenous microbial community in ridge flank crustal fluids and advances our understanding of the potential physiological and phylogenetic diversity of this community.

  9. New geophysical models of Palmer Deep crustal structure

    Science.gov (United States)

    Yakymchuk, M. A.; Levashov, S. P.; Korchagin, I. N.; Bachmutov, V. G.; Solovyov, V. D.

    2009-04-01

    The 2004 (9th) and 2006 (11th) Ukrainian Antarctic expeditions acquired new geoelectrical data (‘short-impulse electromagnetic field formation' - FSPEF, and ‘vertical electric-resonance sounding' - VERS) along profiles across Drake Passage and along Bransfield Strait, Antarctic Peninsula, with the aim of studying the crustal structure of these features down to depths of >30 km. The sounding on this depth in Antarctic region was the first experience of deep modification of the VERS method using. Modelling experience of deep crustal structure by geophysical data with VERS method shows that there is a possibility to investigate the fluid regime, tectonic disturbances and crush zones in basement and local places of submarine volcanic activity too. This technology also gives a possibility to efficiently divide the cross-section on separate stratigraphic subsections in the sounding site and to determine its depth with high accuracy (Levashov et al., 2003; Levashov et al., 2007). Geophysical surveys enabled to yield new data set with information about Drake Passage and Palmer Deep inner crustal structure on broad continental margin of Antarctic Peninsula. Palmer Deep is located on continental (Pacific) shelf of the Antarctic Peninsula near Anvers Island and consists of three deep basins with depths from 1200м to 1500м. These basins were part of glacial outlet during glaciation's period (Rebesco et al., 1998). Geoelectrical models of Palmer Deep crustal structure along three profiles were built on the sounding data in separate points of continental shelf. Heterogeneity of Palmer Deep earth's crust obtained from VERS data modelling testified to processes of tectonic transformations of internal shelf structures. Tectonic factor explains some conformities of the most recent glaciomarine sediments and glacial streams forming during recent shelf-wide glaciations. New information about sediment distribution and inner crustal structure has an important value for searching

  10. Crustal Signatures in Mantle Peridotites From Yakutian Kimberlites

    Science.gov (United States)

    Taylor, L. A.; Spetsius, Z.; Wiesli, R.; Anand, M.; Valley, J.

    2002-12-01

    Peridotites and eclogites are considered as the original hosts for diamonds in the mantle. However, it is now generally agreed that these "mantle" eclogites from kimberlites had their origin in the subduction of oceanic crust beneath the major cratons of the world. One of the first indications for such crustal protoliths was from studies of oxygen and carbon isotopes (e.g., Peter Deines and colleagues, Ian McGregor, as well as our group). Indeed, subsequent studies of such rocks have revealed several additional crustal signatures. A possible scenario involves the subduction of an ophiolite sequence, whereby the basaltic and lower mafic components were metamorphosed, devolatilized/partially melted, and otherwise transformed into eclogites. Being within the diamond-stability field, they later experience metasomatic diamond formation. Surprisingly, the closely associated diamondiferous peridotites are considered to be of original mantle origin. We pose the query: What became of the ultramafic portion at the bottom of the crustal sequence? Could this be the origin of at least some of the mantle peridotites? The restricted δ13C values for P-type (peridotitic) diamonds is commonly used as evidence for the mantle origin of peridotites. However, a compilation of δ13C data, published by Peter Deines and our group, for P-type diamonds, mainly from numerous south African pipes, also shows a significant number of values that are well below the mantle field (to -20 \\permil). Fresh, clean garnets were carefully selected from over a hundred peridotites collected from several Yakutian kimberlites. These were subjected to oxygen-isotope analyses by laser-fluorination at the University of Wisconsin. The majority of the δ18O values plot within the accepted mantle value of 5.5+/-0.4 \\permil (Mattey et al., 1994). However, a significant number (~20%) lies outside this window, both above and below. These values are interpreted to represent the effects of both high- and low

  11. Estimating crustal thickness using SsPmp in regions covered by low-velocity sediments: Imaging the Moho beneath the Southeastern Suture of the Appalachian Margin Experiment (SESAME) array, SE Atlantic Coastal Plain

    Science.gov (United States)

    Parker, E. Horry, Jr.; Hawman, Robert B.; Fischer, Karen M.; Wagner, Lara S.

    2016-09-01

    Deconvolved waveforms for two earthquakes (Mw: 6.0 and 5.8) show clear postcritical SsPmp arrivals for broadband stations deployed across the coastal plain of Georgia, allowing mapping of crustal thickness in spite of strong reverberations generated by low-velocity sediments. Precritical SsPmp arrivals are also identified. For a basement in which velocity increases linearly with depth, a bootstrapped grid search suggests an average basement velocity of 6.5 ± 0.1 km/s and basement thickness of 29.8 ± 2.0 km. Corresponding normal-incidence Moho two-way times (including sediments) are 10.6 ± 0.6 s, consistent with times for events interpreted as Moho reflections on coincident active-source reflection profiles. Modeling of an underplated mafic layer (Vp = 7.2-7.4 km/s) using travel time constraints from SsPmp data and vertical-incidence Moho reflection times yields a total basement thickness of 30-35 km and average basement velocity of 6.35-6.65 km/s for an underplate thickness of 0-15 km.

  12. Trace element differences between Archean, Proterozoic and Phanerozoic crustal components: Implications for crustal growth processes

    Science.gov (United States)

    Tarney, J.; Wyborn, L. E. A.; Sheraton, J. W.; Wyborn, D.

    1988-01-01

    Critical to models for continental crust growth and recycling are the processes through which crustal growth takes place. In particular, it is important to know whether these processes have changed fundamentally with time in response to the earth's thermal evolution, and whether the crustal compositions generated are compatible with crustal remobilization, crustal recycling, or represent primary additions. There are some significant and consistent differences in the major and trace element compositions of crustal components with time which have important implications for crustal growth processes. These will be illustrated with reference to Archean rocks from a number of shield areas, Proterozoic granitoids from Australia and elsewhere, Palaeozoic granitoids from Australia and Scotland, and Mesozoic - recent granitoids from present continental margin belts. Surprisingly some rather simple and consistent patterns energy using this technique. There are then significant differences in compositions of granitoid crustal additions throughout geological time, with a particular type of granitoid apparently dominating a particular time period. This implies that the tectonic processes giving rise to granite generation have changed in response to the earth's thermal evolution.

  13. Isolated ovarian tuberculosis mimicking ovarian carcinoma: Case ...

    African Journals Online (AJOL)

    Although genitourinary tuberculosis is common, reports of isolated ovarian tuberculosis are rare. However, its presentation can mimick that of an ovarian tumour, leading to diagnostic difficulties. A woman of 17 years presented with chronic pelvic pain, weight loss, a right ovarian mass on ultrasound, and a significantly ...

  14. unilatefial congenital multicystic dysplastic kidney mimicking cystic ...

    African Journals Online (AJOL)

    70, N0. 4, 2004. African Journal of Urology 289-290. UNILATEFIAL CONGENITAL MULTICYSTIC DYSPLASTIC KIDNEY. MIMICKING CYSTIC FIENAL CELL CARCINOMA IN AN ADULT. NIGERIAN. A.A. 'SALAKO*, V.A. ADETILOYE**, AND 0.8. OJO***. Departments of Surgery*, Radiology“ and Morbid Anatomy***, Obafemi ...

  15. Degenerated Cystic Uterine Myoma Mimicking Postpartum Haemoperitonium

    Directory of Open Access Journals (Sweden)

    Servet Gençdal

    2017-10-01

    Full Text Available Haemoperitoneum due to spontaneous haemorrhage of intraleiomyoma is a very rare complication of uterine myoma. Acute complications of uterine myoma are seldom seen, but it may be fatal. We hereby report case of a female, who presented with abdominal pain and distension, postpratum, found to have degenerated cystic uterine myoma, mimicking postpartum haemoperitonium.

  16. Nd isotopes and crustal growth rate

    Science.gov (United States)

    Albarede, F.

    1988-01-01

    Sm/Nd isotopic constraints on crustal growth is discussed. In order to constrain Sm/Nd fractionation between continental crust and depleted mantle, an extensive data base of isotopic measurements (assumed to be adequately representative of continental crust) was compiled. The results imply that the evolution of depleted mantles was roughly linear, with no major discontinuities over the course of geologic time. This is different from other determinations of depleting mantle evolution, which show nonlinear behavior. The Sm/Nd evolution lines for continental crust and depleted mantle intersect between 3.8 to 4.0 Ga, which may indicate that the onset of continental growth was later than 4.5 Ga. A mathematical model is described, the results of which imply that time integrated crustal additions from the mantle are about 1.8 to 2.5 cu km/a, whereas crustal subtractions by sediment recycling are about 0.6 to 1.5 cu km/a. This results in a net time integrated crustal growth rate of about 1 cu km/a, which is similar to present day rates determined, for example, by Reymer and Schubert.

  17. Crustal structure of the Khartoum Basin, Sudan

    CSIR Research Space (South Africa)

    El Tahir, N

    2013-05-01

    Full Text Available The crustal structure of the northern part of the Khartoum Basin has been investigated using data from 3 permanent seismic stations within 40 km of Khartoum and two modeling methods, H–k stacking of receiver functions and a joint inversion...

  18. Toward restrictions on boson stars as black hole mimickers

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, F S, E-mail: guzman@ifm.umich.mx [Instituto de Fisica y Matematicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio C3, Cd. Universitaria, 58040 Morelia, Michoacan (Mexico)

    2011-09-22

    The status of boson stars as black hole mimickers is presented among other mimickers. We focus on the analysis of the emission spectrum of a simple accretion disk model. We describe the free parameters that allow a boson star to become a black hole mimicker and present an example of a particular astrophysical case.

  19. Testing Predictions of Continental Insulation using Oceanic Crustal Thicknesses

    Science.gov (United States)

    Hoggard, Mark; Shorttle, Oliver; White, Nicky

    2016-04-01

    The thermal blanketing effect of continental crust has been predicted to lead to elevated temperatures within the upper mantle beneath supercontinents. Initial break-up is associated with increased magmatism and the generation of flood basalts. Continued rifting and sea-floor spreading lead to a steady reduction of this thermal anomaly. Recently, evidence in support of this behaviour has come from the major element geochemistry of mid-ocean ridge basalts, which suggest excess rifting temperatures of ˜ 150 °C that decay over ˜ 100 Ma. We have collated a global inventory of ˜ 1000 seismic reflection profiles and ˜ 500 wide-angle refraction experiments from the oceanic realm. Data are predominantly located along passive margins, but there are also multiple surveys in the centres of the major oceanic basins. Oceanic crustal thickness has been mapped, taking care to avoid areas of secondary magmatic thickening near seamounts or later thinning such as across transform faults. These crustal thicknesses are a proxy for mantle potential temperature at the time of melt formation beneath a mid-ocean ridge system, allowing us to quantify the amplitude and duration of thermal anomalies generated beneath supercontinents. The Jurassic break-up of the Central Atlantic and the Cretaceous rifting that formed the South Atlantic Ocean are both associated with excess temperatures of ˜ 50 °C that have e-folding times of ˜ 50 Ma. In addition to this background trend, excess temperatures reach > 150 °C around the region of the Rio Grande Rise, associated with the present-day Tristan hotspot. The e-folding time of this more local event is ˜ 10 Ma, which mirrors results obtained for the North Atlantic Ocean south of Iceland. In contrast, crustal thicknesses from the Pacific Ocean reveal approximately constant potential temperature through time. This observation is in agreement with predictions, as the western Pacific was formed by rifting of an oceanic plate. In summary

  20. Intramuscular Hemangioma Mimicking an Adnexal Malignancy

    Directory of Open Access Journals (Sweden)

    Selen Dogan

    2013-10-01

    Full Text Available Intramuscular hemangiomas were defined as vascular malformations according to the International Society for the Study of Vascular Anomalies (ISSVA classification. Aggressive appearance on radiologic images but nonaggressive course of these lesions results in diagnostic challenge for the clinicians that are unfamiliar with these lesions. Here, we present a 49-year-old woman as a rare case of mixed type intramuscular hemangioma originating from pelvic floor muscles, mimicking a malignant adnexal mass.

  1. Intramuscular Hemangioma Mimicking an Adnexal Malignancy

    OpenAIRE

    Selen Dogan

    2013-01-01

    Intramuscular hemangiomas were defined as vascular malformations according to the International Society for the Study of Vascular Anomalies (ISSVA) classification. Aggressive appearance on radiologic images but nonaggressive course of these lesions results in diagnostic challenge for the clinicians that are unfamiliar with these lesions. Here, we present a 49-year-old woman as a rare case of mixed type intramuscular hemangioma originating from pelvic floor muscles, mimicking a malignant adnex...

  2. Traumatic bone cyst mimicking radicular cyst.

    Science.gov (United States)

    Dincer, Onur; Kose, Taha Emre; Cankaya, Abdulkadir Burak; Aybar, Buket

    2012-12-09

    Traumatic bone cysts were first defined by Lucas and Blum in 1929. It is classified as an intraosseous pseudocyst. They are asymptomatic and are usually seen during routine radiographical examination. According to the 2002 classification of the WHO, traumatic bone cysts are in miscellaneous lesions. This report describes a 16-year-old male patient who had a traumatic bone cyst that mimicked a radicular cyst.

  3. Mammary Analogue Secretory Carcinoma Mimicking Salivary Adenoma

    OpenAIRE

    Williams, Lindsay; Chiosea, Simion I.

    2013-01-01

    Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland tumor characterized by ETV6 translocation. It appears that prior studies have identified MASC by reviewing salivary gland carcinomas, such as acinic cell carcinoma and adenocarcinoma, not otherwise specified. To address the possibility of MASC mimicking benign salivary neoplasms we reviewed 12 salivary gland (cyst)adenomas diagnosed prior to the discovery of MASC. One encapsulated (cyst)adenoma of the parotid g...

  4. Reports on crustal movements and deformations. [bibliography

    Science.gov (United States)

    Cohen, S. C.; Peck, T.

    1983-01-01

    This Catalog of Reports on Crustal Movements and Deformation is a structured bibliography of scientific papers on the movements of the Earth crust. The catalog summarizes by various subjects papers containing data on the movement of the Earth's surface due to tectonic processes. In preparing the catalog we have included studies of tectonic plate motions, spreading and convergence, microplate rotation, regional crustal deformation strain accumulation and deformations associated with the earthquake cycle, and fault motion. We have also included several papers dealing with models of tectonic plate motion and with crustal stress. Papers which discuss tectonic and geologic history but which do not present rates of movements or deformations and papers which are primarily theoretical analyses have been excluded from the catalog. An index of authors cross-referenced to their publications also appears in the catalog. The catalog covers articles appearing in reviewed technical journals during the years 1970-1981. Although there are citations from about twenty journals most of the items come from the following publications: Journal of Geophysical Research, Tectonophysics, Geological Society of America Bulletin of the Seismological Society of America, Nature, Science, Geophysical Journal of the Royal Astronomical Society, Earth and Planetary Science Letters, and Geology.

  5. Rheology of Melt-bearing Crustal Rocks

    Science.gov (United States)

    Rosenberg, C. L.; Medvedev, S.; Handy, M. R.

    2006-12-01

    A review and reinterpretation of previous experimental data on the deformation of melt-bearing crustal rocks (Rosenberg and Handy, 2005) revealed that the relationship of aggregate strength to melt fraction is non-linear, even if plotted on a linear ordinate and abscissa. At melt fractions, Φ 0.07, the dependence of aggregate strength on Φ is significantly greater than at Φ > 0.07. This melt fraction (Φ= 0.07) marks the transition from a significant increase in the proportion of melt-bearing grain boundaries up to this point to a minor increase thereafter. Therefore, we suggest that the increase of melt-interconnectivity causes the dramatic strength drop between the solidus and a melt fraction of 0.07. A second strength drop occurs at higher melt fractions and corresponds to the breakdown of the solid (crystal) framework, corresponding to the well-known "rheologically critical melt percentage" (RCMP; Arzi, 1978). Although the strength drop at the RCMP is about 4 orders of magnitude, the absolute value of this drop is small compared to the absolute strength of the unmelted aggregate, rendering the RCMP invisible in a linear aggregate strength vs. melt fraction diagram. Predicting the rheological properties and thresholds of melt-bearing crust on the basis of the results and interpretations above is very difficult, because the rheological data base was obtained from experiments performed at undrained conditions in the brittle field. These conditions are unlikely to represent the flow of partially melted crust. The measured strength of most of the experimentally deformed, partially-melted samples corresponds to their maximum differential stress, before the onset of brittle failure, not to their viscous strength during "ductile" (viscous) flow. To overcome these problems, we extrapolated a theoretically-derived flow law for partially melted granite deforming by diffusion-accommodated grain-boundary sliding (Paterson, 2001) and an experimentally-derived flow law for

  6. Crustal Thickness and Structure in Southern Chile: Patagonia plate assembly structures and continental arc modifications

    Science.gov (United States)

    Rodriguez, E. E.; Russo, R. M.

    2016-12-01

    Crustal structure is the product of the processes that operated during a region's tectonic history. For Patagonia, these tectonic processes include its early Paleozoic assembly and accretion to the South America portion of Gondwana, Triassic rifting of Gondwana, and a long history as the upper plate during oceanic subduction since the Mesozoic. To assess the crustal structure and glean insight into how these tectonic processes affected the region, we combined data from two seismic networks, the Chile Ridge Subduction Project and Seismic Experiment of Aisen Chile - yielding a total of 77 broadband seismic stations - deployed from 2004 to 2007. The stations were concentrated 300 km inboard of the Chile trench, above structures unlikely to have been affected by ongoing Chile Ridge subduction. Events suitable for receiver function (RF) analyses (M > 5.9, of various backazimuths, epicentral distances of 30 - 90°) yielded 995 radial RFs, constructed using iterative time deconvolution (Ligorria and Ammon, 1999). We estimated crustal thicknesses and compressional to shear wave velocity ratios (Vp/Vs) using the H-k grid search method (Zhu and Kanamori, 2000); common conversion point (CCP) stacking (Zhu, et al., 2006) allowed imaging of crustal structure. Results limit crustal thicknesses to between 30 and 45 km. The crust varies smoothly from 30 km at the N margin of our study area ( 43°S) to a max depth of 45 km at 44.75°S, shallowing to 30 km at 49°S. On E-W CCP sections north of 46°S, the Moho dips westward, from a depth of 35 at 71°W to 45 km at its deepest near 72.75°W. Beneath the active Southern Volcanic Zone, which is bounded to the west by the Liquiñe-Ofqui fault, the Moho is ambiguous, producing unclear Ps phases possibly reflecting a lack of sharp impedance contrast or poor conversion efficiency at the base of the crust, perhaps due to deep-seated volcanic arc processes. The proximity of the Liquiñe-Ofqui strike-slip fault may also complicate the

  7. Lower Crustal and Moho Reflections Beneath Mount St. Helens

    Science.gov (United States)

    Levander, A.; Kiser, E.; Zelt, C. A.; Creager, K.; Ulberg, C. W.; Schmandt, B.; Hansen, S. M.; Abers, G. A.

    2016-12-01

    The multi-disciplinary project iMUSH (imaging Magma Under St. Helens) was designed to illuminate the magmatic system beneath Mount St Helens (MSH) from the subducting Juan de Fuca slab to the surface using seismic, magnetotelluric, and petrologic data. The iMUSH active source experiment consisted of 23 large shots and 6000 seismograph locations. Included in the active-source seismic experiment were 2 dense linear profiles striking NW-SE and NE-SW, each with over 1000 receivers ( 150 m spacing) and 8 shots. Using the 1D average velocity model around MSH determined from travel-time analysis (Kiser et al., 2016, Geology), we have common-midpoint stacked STA/LTA envelope functions from all of the data along the NW-SE profile. A number of bright reflection events in the CMP section show remarkably good correspondence with abrupt velocity changes that were imaged in the 2D travel-time analysis in the mid to lower crust and at the Moho: Reflections appear at 20-25 km depth at the tops of two lower crustal high velocity (Vp > 7.5 km/s) bodies. One of these high velocity bodies is directly beneath MSH. The other is 40 km SE of MSH, under the Indian Heaven volcanic field, a basaltic field last active 9 ka. We have interpreted the high velocity bodies as cumulates from Quaternary or Tertiary volcanism. Separating the two high Vp bodies is a lower velocity column (Vp ≤ 6.5 km/s) dipping to the SE from the midcrust to the Moho. In the CMP section, the Moho reflection is bright under the region of low velocity and dims beneath both of the high velocity lower crustal bodies. Seismicity associated with the 1980 eruption extended from the summit to 20 km depth, stopping just above the bright reflection at the top of the MSH high Vp body. Deep long period events under MSH, often associated with motion of magmatic fluids, cluster at 20-30 km depth along the southeastern edge of the same reflection. This leads us to suggest that lower crustal magmas migrate along the southeastern

  8. Impedance of tissue-mimicking phantom material under compression

    Directory of Open Access Journals (Sweden)

    Barry Belmont

    2013-02-01

    Full Text Available The bioimpedance of tissues under compression is a field in need of study. While biological tissues can become compressed in a myriad of ways, very few experiments have been conducted to describe the relationship between the passive electrical properties of a material (impedance/admittance during mechanical deformation. Of the investigations that have been conducted, the exodus of fluid from samples under compression has been thought to be the cause of changes in impedance, though until now was not measured directly. Using a soft tissue-mimicking phantom material (tofu whose passive electrical properties are a function of the conducting fluid held within its porous structure, we have shown that the mechanical behavior of a sample under compression can be measured through bioimpedance techniques.

  9. Dislocation model for aseismic crustal deformation at Hollister, California

    Science.gov (United States)

    Matsuura, Mitsuhiro; Jackson, David D.; Cheng, Abe

    1986-01-01

    A model of crustal deformation during the interseismic phase is developed and applied (using the improved Bayesian inversion algorithm described by Jackson and Matsu'ura, 1985) to trilateration data for the USGS Hollister (CA) network. In the model, rigid blocks in motion relative to each other experience friction only in a brittle upper zone, while their ductile lower zones slide freely; the Hollister model comprises five blocks and nine rectangular fault patches. The data and results are presented in tables, graphs, and maps and characterized in detail. The model predicts steady block motion on time scales between 10 yr and 1 Myr, with net motion across the San Andreas/Calaveras fault system 38 + or - 3 mm/yr and brittle/ductile transition depths ranging from 0.4 to 11 km. Two San Andreas segments with higher probabilities of moderate-to-large earthquakes are identified.

  10. A new model of crustal structure of Siberia

    DEFF Research Database (Denmark)

    Cherepanova, Yulia; Artemieva, Irina; Thybo, Hans

    2010-01-01

    , or tectonic similarities, or seismic data reported not along seismic reflection/refraction profiles but as interpolated contour maps are excluded from the new crustal database. Due to uneven quality of seismic data related both to data acquisition problems and interpretation limitations, a special attention......-dependence (we use tectono-thermal ages) of crustal parameters allows for distinguishing the effects of various tectonic processes on the crustal structure. The analysis provides the basis for studies of crustal evolution and geodynamic process in the region where the age of tectonic structures spans over ~4 Ga...

  11. Hypertrophic Nonunion Humerus Mimicking an Enchondroma

    Directory of Open Access Journals (Sweden)

    N. K. Magu

    2014-01-01

    Full Text Available Introduction. Although fractures of humeral shaft show excellent results with conservative management, nonunion does occur. Case Report. We bring forth the case of a young male with a 1.5-year-old hypertrophic nonunion of the humerus mimicking an enchondroma. The initial X-ray images of the patient appeared to be an enchondroma, which only on further evaluation and histopathological analysis was diagnosed conclusively to be a hypertrophic nonunion. Discussion. Enchondromas are often incidentally diagnosed benign tumours. It is however not common to misdiagnose a hypertrophic nonunion to be an enchondroma. We present this case to highlight the unique diagnostic dilemma the treating team had to face.

  12. Central skeletal sarcoidosis mimicking metastatic disease

    Energy Technology Data Exchange (ETDEWEB)

    Talmi, Danit; Smith, Stacy; Mulligan, Michael E. [University of Maryland School of Medicine, Department of Radiology, Baltimore, MD (United States)

    2008-08-15

    Sarcoidosis is a systemic disease that histologically typically shows non-caseating granulomas. The most common radiologic finding is hilar and mediastinal adenopathy. Patients with widely disseminated disease may show involvement of the peripheral appendicular skeleton in 1-13% of such cases. A primary skeletal presentation without other manifestations typical of the disease is rare. We present a case of sarcoidosis in a middle-aged Caucasian man in whom the disease presented with widespread lytic lesions in the axial skeleton and long bones, mimicking metastatic disease. There was no involvement of the peripheral skeleton, skin or lungs. (orig.)

  13. Benzalkonium Chloride Intoxication Mimicking Herpes Zoster Encephalitis

    Directory of Open Access Journals (Sweden)

    Ekrem Güler

    2011-06-01

    Full Text Available Benzalkonium chloride (BAC is a frequently used disinfectant and its most well-known side effect is contact dermatitis. In this report, two children who had vesicular dermatitis, headache, lethargy, fever and encephalopathy mimicking Herpes zoster encephalitis were presented. Their consciousness level improved on the second day. From the medical history it was understood that the mother had applied 20% BAC solution to the scalps of two children. The aim of the presentation of this report is to draw attention to the fact that BAC application to the scalp for treating pediculosis capitis may resemble the herpes encephalitis clinical picture.

  14. Acute Myelogenous Leukemia Mimicking Fulminant Periorbital Cellulitis

    Directory of Open Access Journals (Sweden)

    Abbas Bagheri

    2013-01-01

    Full Text Available Purpose: To report a patient who was referred for orbital cellulitis but was finally diagnosed with acute leukemia. Case Report: A 17-year-old boy presented with fever, periorbital erythema and swelling mimicking periorbital cellulitis. He underwent empiric antibiotic therapy. Complete blood counts revealed leukocytosis with a predominance of immature blast cells. Bone marrow aspiration confirmed the diagnosis of acute myelogenous leukemia. Chemotherapy was initiated resulting in resolution of signs and symptoms. Conclusion: Acute leukemia may mimic periorbital cellulitis and must be considered in the differential diagnosis.

  15. Littoral cell angioma mimicking hepatic tumor

    Directory of Open Access Journals (Sweden)

    Wenhua Liang

    2012-07-01

    Full Text Available Littoral cell angioma is a rare vascular tumor of the spleen that was described by Falk et al. in 1991. Because of the limited number, untypical imaging manifestations, and lack of knowledge on this tumor type, these tumors are often misdiagnosed. In most cases, the tumor presents with multiple small hypoattenuating nodules in the spleen with delayed enhancement. However, solitary littoral cell angiomas have not been well described. We present the CT features of an unusual littoral cell angioma mimicking hepatic tumor.

  16. Immunoglobulin G4-Related Disease Mimicking Asthma

    Directory of Open Access Journals (Sweden)

    Hiroshi Sekiguchi

    2013-01-01

    Full Text Available Immunoglobulin (Ig G4-related disease (also known as ‘IgG4-related sclerosing disease’, ‘IgG4-related systemic disease’ or ‘hyper-IgG4-disease’ is a recently recognized systemic fibroinflammatory disease associated with IgG4-positive plasma cells in tissue lesions. IgG4-related disease was initially described as autoimmune pancreatitis, but it is now known to affect virtually any organ. The authors describe a patient presenting with multi-organ manifestations, including airway inflammation mimicking asthma, pulmonary parenchymal infiltrates, intrathoracic lymphadenopathy, submandibular gland swelling and a kidney mass.

  17. From the Surface Topography to the Upper Mantle, Seismic constraints on the Crustal structure Across Morocco

    Science.gov (United States)

    Carbonell, Ramon; Díaz, Jordi; Gallart, Josep; Gil, Alba; Ayarza, Puy; Palomeras, Immaculada; Levander, Alan; Marti, David; Harnafi, Mimoun

    2015-04-01

    The most characteristic topographic features of Morocco are the Atlas Mountains and the Rif Coordillera. These two orogenic belts are the response of different geodynamic processes acting at lithospheric scale caused by a unique driver, the collision between two tectonic plates. Both are located within the diffuse plate boundary zone separating Africa and Europe. The boundary zone is characterized by a relatively broad zone of deformation that includes Mountain chains in southern Iberia, the Betics and the Rif cordillera in Morocco. The zone delineates the arcuate arc system of Gribraltar. Within the last decade a large international effort have been devoted to the area mostly leaded by Spanish groups with the collaboration of international research teams (including scientist form Europe and USA). Key multi-seismic projects have been developed that aim to constrain the structure, composition and tectonic scenario from south of the Atlas to the Betics, across the Rif cordillera and the Alboran basin. The multidisciplinary research program includes: natural source (earthquakes) recording with temporal deployments of broad band (BB) instrumentation and, controlled source seismic acquisition experiments where, spatially dense recording of wide-angle seismic reflection shot gathers were acquired. The passive experiments consisted on: a transect from Merzouga across the Gibraltar arc and into the Iberian peninsula (untill south of Toledo); a nearly regular grid of BB which was achieve by multiple deployments of a number of BB. The controlled source datasets were able to constrain the crustal structure and provide seismic P-wave propagation velocity models from the coast across the Rif and the Atlas. Travel-time inversion of the controlled source seismic data across the Atlas constraints a crustal root to the south of the High Atlas, and reveals mantle wedge. A limited crustal imbrication also appears in the Middle Atlas. The crustal thickness, does not exceeded 40 km in

  18. Clinical and Histologic Mimickers of Celiac Disease.

    Science.gov (United States)

    Kamboj, Amrit K; Oxentenko, Amy S

    2017-08-17

    Celiac disease is an autoimmune disorder of the small bowel, classically associated with diarrhea, abdominal pain, and malabsorption. The diagnosis of celiac disease is made when there are compatible clinical features, supportive serologic markers, representative histology from the small bowel, and response to a gluten-free diet. Histologic findings associated with celiac disease include intraepithelial lymphocytosis, crypt hyperplasia, villous atrophy, and a chronic inflammatory cell infiltrate in the lamina propria. It is important to recognize and diagnose celiac disease, as strict adherence to a gluten-free diet can lead to resolution of clinical and histologic manifestations of the disease. However, many other entities can present with clinical and/or histologic features of celiac disease. In this review article, we highlight key clinical and histologic mimickers of celiac disease. The evaluation of a patient with serologically negative enteropathy necessitates a carefully elicited history and detailed review by a pathologist. Medications can mimic celiac disease and should be considered in all patients with a serologically negative enteropathy. Many mimickers of celiac disease have clues to the underlying diagnosis, and many have a targeted therapy. It is necessary to provide patients with a correct diagnosis rather than subject them to a lifetime of an unnecessary gluten-free diet.

  19. A classic mimicker of systemic vasculitis.

    Science.gov (United States)

    Moreno-Ariño, Marc; Ortiz-Santamaria, Vera; Deudero Infante, Aída; Ayats Delgado, Montserrat; Novell Teixidó, Francesc

    2016-01-01

    Embolic and constitutional manifestations of intracavitary cardiac tumors are included within the classic mimickers of systemic vasculitis, especially in those in which there are no cardiac manifestations. We present a case report of atrial myxoma in which the patient only presented systemic symptoms and in whom an initial diagnostic approach of systemic vasculitis was made. We also performed a literature search of the cases described. A case report of atrial myxoma with atypical presentation manifested as a systemic disease with no concomitant cardiac symptoms is described. The case report is discussed and 11 cases of atrial myxoma pseudovasculitis described in the literature are reviewed, emphasizing their similarities and differences. Constitutional symptoms and cutaneous manifestations were the most common. Most of the cases showed partial response to glucococorticosteroid treatment, reinforcing the theory of the inflammatory role in its pathogenesis. Mean delayed time to diagnosis was 12.27 months. Atrial myxoma is a systemic vasculitis mimicker, this being difficult to diagnose in the absence of cardiac manifestations. This delay in diagnosis entails serious complications. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  20. Ultrasound artifacts mimicking pleural sliding after pneumonectomy.

    Science.gov (United States)

    Cavaliere, Franco; Zamparelli, Roberto; Soave, Maurizio P; Gargaruti, Riccardo; Scapigliati, Andrea; De Paulis, Stefano

    2014-03-01

    To determine the presence of pleural sliding on chest ultrasonography (US) in a series of patients admitted to a surgical intensive care unit (SICU). Prospective, observational study. 16-bed SICU of a University hospital. 8 patients (7 men, 1 woman), aged 64 - 73 years (mean 67.5 yrs). Seven patients underwent pneumonectomy for pulmonary neoplasms; one patient underwent an atypical lung resection after having undergone a pneumonectomy one year before. None. Chest ultrasounds were performed during mechanical ventilation and spontaneous ventilation after endotracheal tube removal. In both examinations, pleural sliding was searched bilaterally in brightness mode (B-mode) and motion mode (M-mode) on the anterior thoracic wall in the least gravitationally dependent areas. During mechanical ventilation, pleural sliding was always absent on the side of the pneumonectomy and present on the other side. During spontaneous ventilation, some artifacts mimicking pleural sliding were noted on the side of the pneumonectomy both in B-mode and M-mode (presence of the seashore sign) in all patients, except for the one patient who had undergone a pneumonectomy one year earlier. Those artifacts became more pronounced during deep breaths. Ultrasound artifacts mimicking pleural sliding may be observed in the absence of the lung and may originate from the activity of intercostal muscles since they become more evident during deep breathing. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Crustal structure of Bristol Bay Region, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, A.K.; McLean, H.; Marlow, M.S.

    1985-04-01

    Bristol Bay lies along the northern side of the Alaska Peninsula and extends nearly 600 km southwest from the Nushagak lowlands on the Alaska mainland to near Unimak Island. The bay is underlain by a sediment-filled crustal downwarp known as the north Aleutian basin (formerly Bristol basin) that dips southeast toward the Alaska Peninsula and is filled with more than 6 km of strata, dominantly of Cenozoic age. The thickest parts of the basin lie just north of the Alaska Peninsula and, near Port Mollar, are in fault contact with older Mesozoic sedimentary rocks. These Mesozoic rocks form the southern structural boundary of the basin and extend as an accurate belt from at least Cook Inlet to Zhemchug Canyon (central Beringian margin). Offshore multichannel seismic-reflection, sonobuoy seismic-refraction, gravity, and magnetic data collected by the USGS in 1976 and 1982 indicate that the bedrock beneath the central and northern parts of the basin comprises layered, high-velocity, and highly magnetic rocks that are locally deformed. The deep bedrock horizons may be Mesozoic(.) sedimentary units that are underlain by igneous or metamorphic rocks and may correlate with similar rocks of mainland western Alaska and the Alaska Peninsula. Regional structural and geophysical trends for these deep horizons change from northeast-southwest to northwest-southeast beneath the inner Bering shelf and may indicate a major crustal suture along the northern basin edge.

  2. Crustal permeability: Introduction to the special issue

    Science.gov (United States)

    Ingebritsen, Steven E.; Gleeson, Tom

    2015-01-01

    The topic of crustal permeability is of broad interest in light of the controlling effect of permeability on diverse geologic processes and also timely in light of the practical challenges associated with emerging technologies such as hydraulic fracturing for oil and gas production (‘fracking’), enhanced geothermal systems, and geologic carbon sequestration. This special issue of Geofluids is also motivated by the historical dichotomy between the hydrogeologic concept of permeability as a static material property that exerts control on fluid flow and the perspective of economic geologists, geophysicists, and crustal petrologists who have long recognized permeability as a dynamic parameter that changes in response to tectonism, fluid production, and geochemical reactions. Issues associated with fracking, enhanced geothermal systems, and geologic carbon sequestration have already begun to promote a constructive dialog between the static and dynamic views of permeability, and here we have made a conscious effort to include both viewpoints. This special issue also focuses on the quantification of permeability, encompassing both direct measurement of permeability in the uppermost crust and inferential permeability estimates, mainly for the deeper crust.

  3. A relook into the crustal architecture of Laxmi Ridge, northeastern ...

    Indian Academy of Sciences (India)

    derived free-air gravity (FAG) data to derive the crustal structure of Laxmi Ridge and adjacent areas. 2D and 3D crustal modelling suggests that the high resolution FAG low associated with the ridge is due to underplating and that it is of ...

  4. Temperature and redox effect on mineral colonization in Juan de Fuca Ridge flank subsurface crustal fluids

    Directory of Open Access Journals (Sweden)

    Jean-Paul eBaquiran

    2016-03-01

    Full Text Available To examine microbe-mineral interactions in subsurface oceanic crust, we evaluated microbial colonization on crustal minerals that were incubated in borehole fluids for one year at the seafloor wellhead of a crustal borehole observatory (IODP Hole U1301A, Juan de Fuca Ridge flank as compared to an experiment that was not exposed to subsurface crustal fluids (at nearby IODP Hole U1301B. In comparison to previous studies at these same sites, this approach allowed assessment of the effects of temperature, fluid chemistry, and/or mineralogy on colonization patterns of different mineral substrates, and an opportunity to verify the approach of deploying colonization experiments at an observatory wellhead at the seafloor instead of within the borehole. The Hole U1301B deployment did not have biofilm growth, based on microscopy and DNA extraction, thereby confirming the integrity of the colonization design against bottom seawater intrusion. In contrast, the Hole U1301A deployment supported biofilms dominated by Epsilonproteobacteria (43.5% of 370 16S rRNA gene clone sequences and Gammaproteobacteria (29.3%. Sequence analysis revealed overlap in microbial communities between different minerals incubated at the Hole U1301A wellhead, indicating that mineralogy did not separate biofilm structure within the one-year colonization experiment. Differences in the Hole U1301A wellhead biofilm community composition relative to previous studies from within the borehole using similar mineral substrates suggest that temperature and the diffusion of dissolved oxygen through plastic components influenced the mineral colonization experiments positioned at the wellhead. This highlights the capacity of low abundance crustal fluid taxa to rapidly establish communities on diverse mineral substrates under changing environmental conditions such as from temperature and oxygen.

  5. Mimicking Seawater For Culturing Marine Bacteria

    DEFF Research Database (Denmark)

    Rygaard, Anita Mac; Sonnenschein, Eva; Gram, Lone

    2015-01-01

    Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum...... 100-fold; from 8.5 x 101 CFU/ml to 5.2 x 103 CFU/ml, whereas addition of AHLs did not improve culturability on any of the media.The substitution of agar with gellan gum shows great promise for increasing culturability of marine bacteria, and further studies are ongoing. The AHLs used in this study...... were selected based on a previous study determining the most common AHLs produced by marine strains of the Vibrionaceae family. However, their effect on culturability could not be fully explained, so also here further studies are being carried out....

  6. Orbital Lymphoma Mimicking Lacrimal Gland Pleomorphic Adenoma

    Directory of Open Access Journals (Sweden)

    Diego Strianese

    2013-09-01

    Full Text Available Purpose: To describe the case of a patient affected by orbital lymphoma mimicking pleomorphic adenoma of the lacrimal gland. Methods: This was a retrospective case report. Results: We present the case of a patient with 15-year history of slowly progressive left proptosis and inferomedial bulbar dislocation who had the presumptive diagnosis of lacrimal gland pleomorphic adenoma based on clinical and radiological features. The patient underwent lateral orbitotomy and lacrimal gland excision. Postoperative histological features were consistent with low-grade B-cell non-Hodgkin lymphoma. Conclusion: The accepted clinico-radiological criteria used for the diagnosis of lacrimal gland fossa lesions might have a certain false-positive rate, even in recent years. The initial surgical approach with the appropriate choice between fine-needle aspiration biopsies, intraoperative biopsies and lacrimal gland excisions might be a challenge.

  7. Contiguous spinal metastasis mimicking infectious spondylodiscitis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chul Min; Lee, Seung Hun [Dept. of Radiology, Hanyang University Hospital, Seoul (Korea, Republic of); Bae, Ji Yoon [Dept. of Pathology, National Police Hospital, Seoul (Korea, Republic of)

    2015-12-15

    Differential diagnosis between spinal metastasis and infectious spondylodiscitis is one of the occasional challenges in daily clinical practice. We encountered an unusual case of spinal metastasis in a 75-year-old female breast cancer patient that mimicked infectious spondylodiscitis. Magnetic resonance imaging (MRI) showed diffuse bone marrow infiltrations with paraspinal soft tissue infiltrative changes in 5 contiguous cervical vertebrae without significant compression fracture or cortical destruction. These MRI findings made it difficult to differentiate between spinal metastasis and infectious spondylodiscitis. Infectious spondylodiscitis such as tuberculous spondylodiscitis was regarded as the more appropriate diagnosis due to the continuous involvement of > 5 cervical vertebrae. The patient's clinical presentation also supported the presumptive diagnosis of infectious spondylodiscitis rather than spinal metastasis. Intravenous antibiotics were administered, but clinical symptoms worsened despite treatment. After pathologic confirmation by computed tomography-guided biopsy, we were able to confirm a final diagnosis of spinal metastasis.

  8. Inherited cardiomyopathies mimicking arrhythmogenic right ventricular cardiomyopathy.

    Science.gov (United States)

    Roberts, Jason D; Veinot, John P; Rutberg, Julie; Gollob, Michael H

    2010-01-01

    Arrhythmogenic right ventricular cardiomyopathy (ARVC) represents an inherited cardiomyopathy that manifests clinically with malignant ventricular arrhythmias, sudden cardiac death, and less commonly heart failure. The condition is characterized by replacement of the myocardium, primarily of the right ventricle, with fibrofatty tissue. Extensive fibrofatty replacement of the myocardium has been previously thought to be pathognomonic of ARVC; however, this report details two other forms of inherited cardiomyopathy, namely hypertrophic cardiomyopathy (HCM) and the PRKAG2 cardiac syndrome, that were found to have significant fibrofatty myocardial replacement at pathologic examination. This report represents the first documentation of inherited cardiomyopathies mimicking ARVC and highlights the concept that other cardiac conditions can be associated with fibrofatty replacement of the myocardium. Copyright 2010 Elsevier Inc. All rights reserved.

  9. Acute disseminated encephalomyelitis mimicking acute meningoencephalitis.

    Science.gov (United States)

    Ashrafi, Mahmoud Reza; Amirkashani, Davood; Hirbod-Mobarakeh, Armin; Yaghmaei, Bahareh; Tavassoli, Alireza; Manafi, Farzad; Rezaei, Nima

    2013-12-01

    Acute disseminated encephalomyelitis is an inflammatory demyelinating disease of the central nervous system that usually occurs following an antecedent infection or vaccination. Children and young adults are predominantly affected, but it has low incidence in children younger than 3 years. The disease manifests with a wide range of neurological abnormalities and a variable combination of fever, headache, meningism, convulsion and cranial nerve palsies, and there are no pathognomonic clinical or laboratory findings. So, establishment of definitive diagnosis is challenging in infants. This challenge may result in delayed diagnosis and consequently delayed treatment of acute disseminated encephalomyelitis, which may cause permanent neurological disability. Herein, we report an infant with acute disseminated encephalomyelitis, who mimicked the symptoms of meningoencephalitis and the correct diagnosis and treatment were delayed till the development of a severe phase of the disease.

  10. Tentorium schwannoma mimicking meningioma: an unusual location.

    Science.gov (United States)

    Calişaneller, Tarkan; Ozen, Ozlem; Altinörs, Nur; Caner, Hakan

    2008-07-01

    A 60-year-old female was admitted to our clinic complaining of a long-lasting headache. Cranial magnetic resonance imagining examination of the patient revealed a 22x24 mm extra-axial, well-demarcated, mass lesion based on the left tentorium. The patient underwent a craniotomy and the tumor was totally excised with the adjacent tentorium. The histopathological examination of the tumor complied with the diagnosis of schwannoma. The rest of the clinical course was uneventful and the patient was released from the hospital without any neurological deficit. Intracranial schwannomas can rarely originate from atypical dural locations and radiological techniques are not always helpful in distinguishing tentorial schwannoma from tentorial meningioma. We presented a patient with a tentorium schwannoma mimicking meningioma and discussed the current literature.

  11. Mapping crustal thinning beneath the Eastern Pyrenees

    Science.gov (United States)

    Diaz, Jordi; Chevrot, Sebastien; Verges, Jaume; Sylvander, Matthieu; Ruiz, Mario; Antonio-Vigil, Amanda

    2017-04-01

    The eastern termination of the Pyrenees is a complex region marked by two large tectonic events, the building of the Pyrenees during the Alpine orogeny and the Neogene extensional processes associated to the rotation of the Sardinia-Corsica block and the opening of the Valencia Trough. This complex tectonic history has left major imprints in crustal structures. Previous studies based on gravity data and active seismic profiles have documented a crustal thinning from 40-45 km about 80 km to the west of the Mediterranean coastline to less than 25 km beneath the eastern termination of the Pyrenees. To progress in the knowledge of the geometry of this transition, two passive seismic profiles have been acquired from mid 2015 to late 2016 within the OROGEN project, an academic-industrial collaboration between CNRS-Total-BRGM and CSIC. Up to 38 broad-band stations were deployed along two orthogonal lines, with an interstation spacing close to 10 km. First results of receiver function migration on the E-W profile suggest a smooth Moho thinning smoothly from 40 km beneath the western termination of the line to 23 km close to the coastline. The NNE-SSW profile shows a clearly defined Moho beneath Iberia, slightly deepening from 32 to 35 km northwards, a 28-30 km thick crust underneath the North Pyrenean Front Thrust and a complex geometry in the Axial Zone. Data from natural events located in the Gulf of Roses and near the intersecting point of the profiles have been recorded along the lines, hence allowing to produce wide angle reflection/refraction profiles providing additional constraints on the geometry of the crust/mantle boundary in the Eastern Pyrenees. These new results will be integrated with the available geophysical and geologic information for a more accurate geodynamical interpretation of the results. (Additional founding by the MISTERIOS project, CGL2013-48601-C2-1-R)

  12. Crustal structure of China from deep seismic sounding profiles

    Science.gov (United States)

    Li, S.; Mooney, W.D.

    1998-01-01

    More than 36,000 km of Deep Seismic Sounding (DSS) profiles have been collected in China since 1958. However, the results of these profiles are not well known in the West due to the language barrier. In this paper, we summarize the crustal structure of China with a new contour map of crustal thickness, nine representative crustal columns, and maps showing profile locations, average crustal velocity, and Pn velocity. The most remarkable aspect of the crustal structure of China is the well known 70+ km thickness of the crust of the Tibetan Plateau. The thick (45-70 km) crust of western China is separated from the thinner (30-45 km) crust of eastern China by the north-south trending seismic belt (105??E). The average crustal velocity of China ranges from 6.15 to 6.45 km/s, indicating a felsic-to-intermediate bulk crustal composition. Upper mantle (Pn) velocities are 8.0 ?? 0.2 km/s, equal to the global continental average. We interpret these results in terms of the most recent thermo-tectonic events that have modified the crust. In much of eastern China, Cenoxoic crustal extension has produced a thin crust with a low average crustal velocity, similar to western Europe and the Basin and Range Province, western USA. In western China, Mesozoic and Cenoxoic arc-continent and continent-continent collisions have led to crustal growth and thickening. Inferences on the process of crustal thickening are provided by the deep crustal velocity structure as determined by DSS profiles and other seismological studies. A high velocity (7.0-7.4 km/s) lower-crustal layer has been reported in western China only beneath the southernmost Tibetan Plateau. We identity this high-velocity layer as the cold lower crust of the subducting Indian plate. As the Indian crust is injected northward into the Tibetan lower crust, it heats and assimilates by partial melting, a process that results in a reduction in the seismic velocity of the lower crust in the central and northern Tibetan Plateau

  13. Evolution of crustal thickening in the central Andes, Bolivia

    Science.gov (United States)

    Eichelberger, Nathan; McQuarrie, Nadine; Ryan, Jamie; Karimi, Bobak; Beck, Susan; Zandt, George

    2015-09-01

    Paleoelevation histories from the central Andes in Bolivia have suggested that the geodynamic evolution of the region has been punctuated by periods of large-scale lithospheric removal that drive rapid increases in elevation at the surface. Here, we evaluate viable times and locations of material loss using a map-view reconstruction of the Bolivian orocline displacement field to forward-model predicted crustal thicknesses. Two volumetric models are presented that test assumed pre-deformation crustal thicknesses of 35 km and 40 km. Both models predict that modern crustal thicknesses were achieved first in the northern Eastern Cordillera (EC) by 30-20 Ma but remained below modern in the southern EC until ≤10 Ma. The Altiplano is predicted to have achieved modern crustal thickness after 10 Ma but only with a pre-deformation thickness of 50 km, including 10 km of sediment. At the final stage, the models predict 8-25% regional excess crustal volume compared to modern thickness, largely concentrated in the northern EC. The excess predicted volume from 20 to 0 Ma can be accounted for by: 1) crustal flow to the WC and/or Peru, 2) localized removal of the lower crust, or 3) a combination of the two. Only models with initial crustal thicknesses >35 km predict excess volumes sufficient to account for potential crustal thickness deficits in Peru and allow for lower crustal loss. However, both initial thickness models predict that modern crustal thicknesses were achieved over the same time periods that paleoelevation histories indicate the development of modern elevations. Localized removal of lower crust is only necessary in the northern EC where crustal thickness exceeds modern by 20 Ma, prior to paleoelevation estimates of modern elevations by 15 Ma. In the Altiplano, crustal thicknesses match modern values at 10 Ma and can only exceed modern values by 5 Ma, post-dating when modern elevations were thought to have been established. Collectively, these models predict that

  14. CT Findings of Foreign Body Reaction to a Retained Endoloop Ligature Plastic Tube Mimicking Acute Appendicitis: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Jae Hong; Kang, Chae Hoon; Choi, Soo-Jung; Park, Man Soo; Jung, Seung Mun; Ryu, Dae Shick; Shin, Dong Rock [Department of Radiology, Asan Foundation, GangNeung Asan Hospital, University of Ulsan College of Medicine, Gangneung 25440 (Korea, Republic of)

    2016-11-01

    Many hospitals experience one or more retained surgical instrument events with risk of patient morbidity and medicolegal problems. Identification of retained surgical instrument is important. The radiologists should be familiar with imaging finding of retained surgical instrument. In a 62-year-old female with a retained plastic tube, localized peritoneal infiltration around air-containing tubular structure mimicked acute appendicitis on abdomen computed tomography (CT), one year after laparoscopic cholecystectomy. We reported CT findings of foreign body reaction related to retained Endoloop ligature plastic tube mimicking acute appendicitis.

  15. CT findings of foreign body reaction to retained endoloop ligature plastic tube mimicking acute appendicitis: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Jae Hong; Kang, Chae Hoon; Choi, Soo Jung; Park, Man Soo; Jung, Seung Mun; Ryu, Dae Shick; Shin, Dong Rock [Dept. of Radiology, GangNeung Asan Hospital, University of Ulsan College of Medicine, Gangneung (Korea, Republic of)

    2016-07-15

    Many hospitals experience one or more retained surgical instrument events with risk of patient morbidity and medicolegal problems. Identification of retained surgical instrument is important. The radiologists should be familiar with imaging finding of retained surgical instrument. In a 62-year-old female with a retained plastic tube, localized peritoneal infiltration around air-containing tubular structure mimicked acute appendicitis on abdomen computed tomography (CT), one year after laparoscopic cholecystectomy. We reported CT findings of foreign body reaction related to retained Endoloop ligature plastic tube mimicking acute appendicitis.

  16. Bio-Inspired PVDF-Based, Mouse Whisker Mimicking, Tactile Sensor

    Directory of Open Access Journals (Sweden)

    Mohsin Islam Tiwana

    2016-10-01

    Full Text Available The design and fabrication of a Polyvinylidene fluoride (PVDF based, mouse (or rodent whisker mimicking, tactile sensor is presented. Unlike previous designs reported in the literature, this sensor mimics the mouse whisker not only mechanically, but it also makes macro movements just like a real mouse whisker in a natural environment. We have developed a mathematical model and performed finite element analysis using COMSOL, in order to optimise the whisker to have the same natural frequency as that of a biological whisker. Similarly, we have developed a control system that enables the whisker mimicking sensor to vibrate at variable frequencies and conducted practical experiments to validate the response of the sensor. The natural frequency of the whisker can be designed anywhere between 35 and 110 Hz, the same as a biological whisker, by choosing different materials and physical dimensions. The control system of this sensor enables the whisker to vibrate between 5 and 236 Hz.

  17. Seismically constrained two-dimensional crustal thermal structure of ...

    Indian Academy of Sciences (India)

    m2 for stable ... Keywords. Cambay basin; P-wave velocity; heat flow; heat generation; 2-D modelling; crustal thermal structure; Moho depth; Curie isotherm. ... major disadvantage of ignoring the effect of lateral variation in the heat production ...

  18. Lymphocitic infundibuloneurohypophysitis mimicking a pituitary adenoma

    Directory of Open Access Journals (Sweden)

    Hubertus Maximilian Mehdorn

    2011-04-01

    Full Text Available A rare case of infundibulo-neurohypophysitis mimicking a pituitary adenoma is presented. A 69-years-old female patient developed polyuria and polydipsia. Laboratory analysis revealed central diabetes insipidus. No hormonal abnormalities. Cranial-magnetic resonance imaging (MRI showed a left sided mass in the adenohypophysis presuming a pituitary adenoma. The mass had contact to both internal carotids. Admission to our department for neurosurgical treatment followed. Ophthalmo - logic examination and neurological examination yielded normal findings. A second MRI focussing on the sellar-region showed a leftsided (T2-MRI.hyperintense, distended adenohypophysis, without contrast enhancement in T1. The stalk appeared thickened. T1- weighted sequences of the neurohypophysis showed loss of signal intensity. We diagnosed an infundibulo-neurohypophysitis and abstai - ned from surgical removal. The patient was discharged under treatment with corticosteroids and desmopressin. Hypophysitis is rare and shows special clinical characteristics. Despite defined radiological features to differentiate between hypophysitis and adenoma the possibility of misdiagnosis, and unnecessary surgical procedures, should always kept in mind.

  19. [Infestation with Enterobius vermicularis mimicking appendicitis].

    Science.gov (United States)

    Levens, Afra M A; Schurink, Maarten; Koetse, Harma A; van Baren, Robertine

    2014-01-01

    Gastrointestinal infestation with the parasite Enterobius vermicularis is common in humans and is usually harmless. Anal pruritus is the most characteristic symptom, but the parasites can cause severe abdominal pain mimicking appendicitis. Early recognition can prevent an unnecessary appendectomy. A six-year-old girl reported to the accident and emergency department with pain in the lower right abdominal region. She was admitted and treated for suspected perforated appendix, following physical examination supplemented with an abdominal CT scan. After antibiotic treatment the symptoms disappeared as did the abscess, apart from a minor amount of residual infiltrate. She was then readmitted twice with recurrent abdominal pain without radiological evidence of an abdominal focus. We decided to conduct a diagnostic laparoscopy and an elective appendectomy à froid. During this procedure living worms were found in the appendix. Treatment with the anthelminthicum mebendazol was effective. Gastro-intestinal infestation with E. vermicularis is very common, especially in young children. This infestation is usually harmless, but can mimic appendicitis. This infestation is easily treatable with mebendazol.

  20. Microfabricated adhesive mimicking gecko foot-hair.

    Science.gov (United States)

    Geim, A K; Dubonos, S V; Grigorieva, I V; Novoselov, K S; Zhukov, A A; Shapoval, S Yu

    2003-07-01

    The amazing climbing ability of geckos has attracted the interest of philosophers and scientists alike for centuries. However, only in the past few years has progress been made in understanding the mechanism behind this ability, which relies on submicrometre keratin hairs covering the soles of geckos. Each hair produces a miniscule force approximately 10(-7) N (due to van der Waals and/or capillary interactions) but millions of hairs acting together create a formidable adhesion of approximately 10 N x cm(-2): sufficient to keep geckos firmly on their feet, even when upside down on a glass ceiling. It is very tempting to create a new type of adhesive by mimicking the gecko mechanism. Here we report on a prototype of such 'gecko tape' made by microfabrication of dense arrays of flexible plastic pillars, the geometry of which is optimized to ensure their collective adhesion. Our approach shows a way to manufacture self-cleaning, re-attachable dry adhesives, although problems related to their durability and mass production are yet to be resolved.

  1. Microfabricated adhesive mimicking gecko foot-hair

    Science.gov (United States)

    Geim, A. K.; Dubonos, S. V.; Grigorieva, I. V.; Novoselov, K. S.; Zhukov, A. A.; Shapoval, S. Yu.

    2003-07-01

    The amazing climbing ability of geckos has attracted the interest of philosophers and scientists alike for centuries. However, only in the past few years has progress been made in understanding the mechanism behind this ability, which relies on submicrometre keratin hairs covering the soles of geckos. Each hair produces a miniscule force ~10-7 N (due to van der Waals and/or capillary interactions) but millions of hairs acting together create a formidable adhesion of ~10 N cm-2: sufficient to keep geckos firmly on their feet, even when upside down on a glass ceiling. It is very tempting to create a new type of adhesive by mimicking the gecko mechanism. Here we report on a prototype of such 'gecko tape' made by microfabrication of dense arrays of flexible plastic pillars, the geometry of which is optimized to ensure their collective adhesion. Our approach shows a way to manufacture self-cleaning, re-attachable dry adhesives, although problems related to their durability and mass production are yet to be resolved.

  2. Hyperdense dots mimicking microcalcifications : Mammographic findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nam Hyeon; Park, Jeong Mi; Goo, Hyun Woo; Bang, Sun Woo [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    1996-12-01

    To differentiate fine hyperdense dots mimicking microcalcifications from true microcalcifications on mammography. Mammograms showing hyperdense dots in ten patients (mean age, 59 years) were evaluated. Two radiologists were asked to differentiate with the naked eye the hyperdense dots seen on ten mammograms and proven microcalcifications seen on ten mammograms. Densitometry was also performed for all lesions and the contrast index was calculated. The shape and distribution of the hyperdense dots were evaluated and enquires were made regarding any history of breast disease and corresponding treatment. Biopsies were performed for two patients with hyperdense dots. Two radiologists made correct diagnoses in 19/20 cases(95%). The contrast index was 0.10-0.88 (mean 0.58) for hyperdense dots and 0.02-0.45 (mean 0.17) for true microcalcifications. The hyperdense dots were finer and homogeneously rounder than the microcalcifications. Distribution of the hyperdense dots was more superficial in subcutaneous fat (seven cases) and subareolar area (six cases). All ten patients with hyperdense dots had history of mastitis and abscesses and had been treated by open drainage (six cases) and/or folk remedy (four cases). In eight patients, herb patches had been attached. Biopsies of hyperdense dots did not show any microcalcification or evidence of malignancy. These hyperdense dots were seen mainly in older patients. Their characteristic density, shape, distribution and clinical history makes differential diagnosis from true microcalcifications easy and could reduce unnecessary diagnostic procedures such as surgical biopsy.

  3. Mammary analogue secretory carcinoma mimicking salivary adenoma.

    Science.gov (United States)

    Williams, Lindsay; Chiosea, Simion I

    2013-12-01

    Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland tumor characterized by ETV6 translocation. It appears that prior studies have identified MASC by reviewing salivary gland carcinomas, such as acinic cell carcinoma and adenocarcinoma, not otherwise specified. To address the possibility of MASC mimicking benign salivary neoplasms we reviewed 12 salivary gland (cyst)adenomas diagnosed prior to the discovery of MASC. One encapsulated (cyst)adenoma of the parotid gland demonstrated features of MASC. The diagnosis was confirmed by fluorescence in situ hybridization with an ETV6 break-apart probe. An unusual complex pattern of ETV6 rearrangement with duplication of the telomeric/distal ETV6 probe was identified. This case illustrates that MASC may mimic salivary (cyst)adenomas. To more accurately assess true clinical and morphologic spectrum of MASC, future studies may have to include review of salivary (cyst)adenomas. The differential diagnosis of MASC may have to be expanded to include cases resembling salivary (cyst)adenomas.

  4. Non-harmful insertion of data mimicking computer network attacks

    Energy Technology Data Exchange (ETDEWEB)

    Neil, Joshua Charles; Kent, Alexander; Hash, Jr, Curtis Lee

    2016-06-21

    Non-harmful data mimicking computer network attacks may be inserted in a computer network. Anomalous real network connections may be generated between a plurality of computing systems in the network. Data mimicking an attack may also be generated. The generated data may be transmitted between the plurality of computing systems using the real network connections and measured to determine whether an attack is detected.

  5. Crustal Structure beneath Mexico from Receiver Functions

    Science.gov (United States)

    Espindola, V.; Quintanar, L.; Espindola, J.

    2011-12-01

    The Servicio Sismológico Nacional (SSN) is Mexico's official organism in charge of the observation of seismicity in the country. Operated by the Universidad Nacional Autonoma de Mexico, it counts with 32 broadband stations deployed throughout the country. The coverage includes most of the geologic provinces of the territory, which vary widely in their geologic characteristics. The availability of records from teleseisms at those stations makes feasible to obtain sound and homogeneous estimates of the structure of the crust in the Mexican territory through the analysis of receiver functions (RF). In this work we present the results of the analysis of RF obtained from events registered from 1998 to 2009 in the 32 stations of the SSN. The RF technique, which uses converted phases at major velocity discontinuities, is a well established technique to infer the velocity contrasts and thickness of the underlying crust. Using this method we were able to infer the depth of the Moho, a major intracrustal discontinuity and in some cases the depth to the base of the subducting plate. We present maps of crustal thickness in Mexico, which varies between about 29 km in the Yucatan peninsula to more than 40 km in central Mexico. Poisson's coefficient varies between 0.19 and 0.30. The position of the descending slab shows a large variation in the subduction angle (from about 6° in the SE margin of the Pacific coast to about 60° in the NW ) as has been found from other techniques.

  6. Ionospheric precursors for crustal earthquakes in Italy

    Directory of Open Access Journals (Sweden)

    L. Perrone

    2010-04-01

    Full Text Available Crustal earthquakes with magnitude 6.0>M≥5.5 observed in Italy for the period 1979–2009 including the last one at L'Aquila on 6 April 2009 were considered to check if the earlier obtained relationships for ionospheric precursors for strong Japanese earthquakes are valid for the Italian moderate earthquakes. The ionospheric precursors are based on the observed variations of the sporadic E-layer parameters (h'Es, fbEs and foF2 at the ionospheric station Rome. Empirical dependencies for the seismo-ionospheric disturbances relating the earthquake magnitude and the epicenter distance are obtained and they have been shown to be similar to those obtained earlier for Japanese earthquakes. The dependences indicate the process of spreading the disturbance from the epicenter towards periphery during the earthquake preparation process. Large lead times for the precursor occurrence (up to 34 days for M=5.8–5.9 tells about a prolong preparation period. A possibility of using the obtained relationships for the earthquakes prediction is discussed.

  7. The Sub-Crustal Stress Field in the Taiwan Region

    Directory of Open Access Journals (Sweden)

    Robert Tenzer and Mehdi Eshagh

    2015-01-01

    Full Text Available We investigate the sub-crustal stress in the Taiwan region. A tectonic configuration in this region is dominated by a collision between the Philippine oceanic plate and the Eurasian continental margin. The horizontal components of the sub-crustal stress are computed based on the modified _ formulae in terms of the stress function with a subsequent numerical differentiation. This modification increases the (degree-dependent convergence domain of the asymptotically-convergent series and consequently allows evaluating the stress components to a spectral resolution, which is compatible with currently available global crustal models. Moreover, the solution to the Vening _ (VMM inverse isostasy problem is explicitly incorporated in the stress function definition. The sub-crustal stress is then computed for a variable Moho geometry, instead of assuming only a constant Moho depth. The regional results reveal that the Philippine plate subduction underneath the Eurasian continental margin generates the shear sub-crustal stress along the Ryukyu Trench. Some stress anomalies associated with this subduction are also detected along both sides of the Okinawa Trough. A tensional stress along this divergent tectonic plate boundary is attributed to a back-arc rifting. The sub-crustal stress, which is generated by a (reverse subduction of the Eurasian plate under the Philippine plate, propagates along both sides of the Luzon (volcanic Arc. This stress field has a prevailing compressional pattern.

  8. Crustal thickness investigation on three broadband stations in Northern Sumatra

    Science.gov (United States)

    Anggono, T.; Syuhada; Soedjatmiko, B.; Amran, A.

    2017-04-01

    We present a preliminary result of crustal thickness in Northern Sumatra from receiver function analysis and grid search. Total of 111 teleseismic events from three broadband stations (TPTI, KCSI, and BSI) of IA-Network were used to calculate the receiver functions. We identified direct P and S arrival from the receiver function. Converted phases Ps were relatively clear for all three broadband stations. Ps-P time was estimated about 2 - 3 s, 2 s, and 5 - 6 s for station TPTI, KCSI, and BSI, respectively. We applied H-k stacking method to obtain crustal thickness and Vp/Vs ratio beneath the three broadband stations. At station TPTI, we obtained the crustal thickness is about 19.54 ± 3.84 km, Vp/Vs ratio is about 1.73 ± 0.14. At station KCSI, the crustal thickness was estimated to be 37.07 ± 4.47 km, Vp/Vs ratio is about 1.84 ± 0.10. At station BSI, which is located to the north of these two stations, the crustal thickness was estimated to be 40.56 ± 2.26 km, Vp/Vs ratio is about 1.81 ± 0.05. These results show relatively large variation of crustal thickness in the Northern Sumatra.

  9. Invasive Pulmonary Aspergillosis-mimicking Tuberculosis.

    Science.gov (United States)

    Kim, Sung-Han; Kim, Mi Young; Hong, Sun In; Jung, Jiwon; Lee, Hyun Joo; Yun, Sung-Cheol; Lee, Sang-Oh; Choi, Sang-Ho; Kim, Yang Soo; Woo, Jun Hee

    2015-07-01

    Pulmonary tuberculosis is occasionally confused with invasive pulmonary aspergillosis (IPA) in transplant recipients, since clinical suspicion and early diagnosis of pulmonary tuberculosis and IPA rely heavily on imaging modes such as computed tomography (CT). We therefore investigated IPA-mimicking tuberculosis in transplant recipients. All adult transplant recipients who developed tuberculosis or IPA at a tertiary hospital in an intermediate tuberculosis-burden country during a 6-year period were enrolled. First, we tested whether experienced radiologists could differentiate pulmonary tuberculosis from IPA. Second, we determined which radiologic findings could help us differentiate them. During the study period, 28 transplant recipients developed pulmonary tuberculosis after transplantation, and 80 patients developed IPA after transplantation. Two experienced radiologists scored blindly 28 tuberculosis and 50 randomly selected IPA cases. The sensitivities of radiologists A and B for IPA were 78% and 68%, respectively (poor agreement, kappa value = 0.25). The sensitivities of radiologists A and B for tuberculosis were 64% and 61%, respectively (excellent agreement, kappa value = 0.77). We then compared the CT findings of the 28 patients with tuberculosis and 80 patients with IPA. Infarct-shaped consolidations and smooth bronchial wall thickening were more frequent in IPA, and mass-shaped consolidations and centrilobular nodules (tuberculosis. Certain CT findings appear to be helpful in differentiating between IPA and tuberculosis. Nevertheless, the CT findings of about one-third of pulmonary tuberculosis cases in transplant recipients are very close to those of IPA. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  10. Noncavernous arteriovenous shunts mimicking carotid cavernous fistulae.

    Science.gov (United States)

    Kobkitsuksakul, Chai; Jiarakongmun, Pakorn; Chanthanaphak, Ekachat; Pongpech, Sirintara

    2016-01-01

    The classic symptoms and signs of carotid cavernous sinus fistula or cavernous sinus dural arteriovenous fistula (AVF) consist of eye redness, exophthalmos, and gaze abnormality. The angiography findings typically consist of arteriovenous shunt at cavernous sinus with ophthalmic venous drainage with or without cortical venous reflux. In rare circumstances, the shunts are localized outside the cavernous sinus, but mimic symptoms and radiography of the cavernous shunt. We would like to present the other locations of the arteriovenous shunt, which mimic the clinical presentation of carotid cavernous fistulae, and analyze venous drainages. We retrospectively examined the records of 350 patients who were given provisional diagnoses of carotid cavernous sinus fistulae or cavernous sinus dural AVF in the division of Interventional Neuroradiology, Ramathibodi Hospital, Bangkok between 2008 and 2014. Any patient with cavernous arteriovenous shunt was excluded. Of those 350 patients, 10 patients (2.85%) were identified as having noncavernous sinus AVF. The angiographic diagnoses consisted of three anterior condylar (hypoglossal) dural AVF, two traumatic middle meningeal AVF, one lesser sphenoid wing dural AVF, one vertebro-vertebral fistula (VVF), one intraorbital AVF, one direct dural artery to cortical vein dural AVF, and one transverse-sigmoid dural AVF. Six cases (60%) were found to have venous efferent obstruction. Arteriovenous shunts mimicking the cavernous AVF are rare, with a prevalence of only 2.85% in this series. The clinical presentation mainly depends on venous outflow. The venous outlet of the arteriovenous shunts is influenced by venous afferent-efferent patterns according to the venous anatomy of the central nervous system and the skull base, as well as by architectural disturbance, specifically, obstruction of the venous outflow.

  11. Plume-driven plumbing and crustal formation in Iceland

    Science.gov (United States)

    Allen, R.M.; Nolet, G.; Morgan, W.J.; Vogfjord, K.; Nettles, M.; Ekstrom, G.; Bergsson, B.H.; Erlendsson, P.; Foulger, G.R.; Jakobsdottir, S.; Julian, B.R.; Pritchard, M.; Ragnarsson, S.; Stefansson, R.

    2002-01-01

    Through combination of surface wave and body wave constraints we derive a three-dimensional (3-D) crustal S velocity model and Moho map for Iceland. It reveals a vast plumbing system feeding mantle plume melt into upper crustal magma chambers where crustal formation takes place. The method is based on the partitioned waveform inversion to which we add additional observations. Love waves from six local events recorded on the HOTSPOT-SIL networks are fitted, Sn travel times from the same events measured, previous observations of crustal thickness are added, and all three sets of constraints simultaneously inverted for our 3-D model. In the upper crust (0-15 km) an elongated low-velocity region extends along the length of the Northern, Eastern and Western Neovolcanic Zones. The lowest velocities (-7%) are found at 5-10 km below the two most active volcanic complexes: Hekla and Bardarbunga-Grimsvotn. In the lower crust (>15 km) the low-velocity region can be represented as a vertical cylinder beneath central Iceland. The low-velocity structure is interpreted as the thermal halo of pipe work which connects the region of melt generation in the uppermost mantle beneath central Iceland to active volcanoes along the neovolcanic zones. Crustal thickness in Iceland varies from 15-20 km beneath the Reykjanes Peninsula, Krafla and the extinct Snfellsnes rift zone, to 46 km beneath central Iceland. The average crustal thickness is 29 km. The variations in thickness can be explained in terms of the temporal variation in plume productivity over the last ~20 Myr, the Snfellsnes rift zone being active during a minimum in plume productivity. Variations in crustal thickness do not depart significantly from an isostatically predicted crustal thickness. The best fit linear isostatic relation implies an average density jump of 4% across the Moho. Rare earth element inversions of basalt compositions on Iceland suggest a melt thickness (i.e., crustal thickness) of 15-20 km, given passive

  12. Deep structure beneath Lake Ontario: Crustal-scale Grenville subdivisions

    Science.gov (United States)

    Forsyth, D. A.; Milkereit, B.; Zelt, Colin A.; White, D. J.; Easton, R. M.; Hutchinson, Deborah R.

    1994-01-01

    Lake Ontario marine seismic data reveal major Grenville crustal subdivisions beneath central and southern Lake Ontario separated by interpreted shear zones that extend to the lower crust. A shear zone bounded transition between the Elzevir and Frontenac terranes exposed north of Lake Ontario is linked to a seismically defined shear zone beneath central Lake Ontario by prominent aeromagnetic and gravity anomalies, easterly dipping wide-angle reflections, and fractures in Paleozoic strata. We suggest the central Lake Ontario zone represents crustal-scale deformation along an Elzevir–Frontenac boundary zone that extends from outcrop to the south shore of Lake Ontario.Seismic images from Lake Ontario and the exposed western Central Metasedimentary Belt are dominated by crustal-scale shear zones and reflection geometries featuring arcuate reflections truncated at their bases by apparent east-dipping linear reflections. The images show that zones analogous to the interpreted Grenville Front Tectonic Zone are also present within the Central Metasedimentary Belt and support models of northwest-directed crustal shortening for Grenvillian deep crustal deformation beneath most of southeastern Ontario.A Precambrian basement high, the Iroquoian high, is defined by a thinning of generally horizontal Paleozoic strata over a crestal area above the basement shear zone beneath central Lake Ontario. The Iroquoian high helps explain the peninsular extension into Lake Ontario forming Prince Edward County, the occurrence of Precambrian inlier outcrops in Prince Edward County, and Paleozoic fractures forming the Clarendon–Linden structure in New York.

  13. Deep Crustal Structure Northeastern Gulf of Mexico

    Science.gov (United States)

    Christeson, Gail; Eddy, Drew; van Avendonk, Harm; Norton, Ian; Karner, Garry; Johnson, Chris; Kneller, Erik; Snedden, John

    2013-04-01

    The Gulf of Mexico is a small ocean basin between the US and Mexico that opened up soon after the breakup of Pangea. Although the area has been heavily surveyed with seismic reflection profiles, the deep structure of the region is poorly understood because of lack of penetration beneath the thick sediments and salt. We present the results of two wide-angle seismic refraction profiles in the northeastern Gulf of Mexico that constrain seismic velocities and thicknesses of the sediments and crust from the continental shelf to deep ocean basin. Profile GUMBO 3 extends 523 km from offshore Alabama south-southwest via the De Soto Canyon to the central Gulf of Mexico, while GUMBO 4 extends 507 km from the northwestern Florida peninsula across the Florida Escarpment to the central Gulf of Mexico. On both profiles, ocean bottom seismometers were positioned at 12-km spacing, and recorded air gun shots at offsets >100 km. We use a tomographic inversion of first-arrival and secondary travel time picks from these data to build a layered velocity model (water, sediments, crystalline crust, mantle) along each profile. On GUMBO 3 and GUMBO 4 the thickness of crystalline crust from the continental shelf to the deep basin decreases from ~25 km to ~7 km (GUMBO 4) or ~8 km (GUMBO 3) over a horizontal distance of ~150 km. Velocities of 7-7.5 km/s are observed at the base of the crust along most of GUMBO 3, while velocities of 6.5-7 km/s are observed at similar depths along GUMBO 4. We suggest that higher lower crustal velocities, and thicker oceanic crust, on GUMBO 3 compared to GUMBO 4 may be explained by elevated syn-rift mantle temperatures in the vicinity of the De Soto Canyon and South Georgia Rift during rifting and continental breakup. We have integrated seismic refraction, seismic reflection, and well data to interpret sequence stratigraphic units along GUMBO 3 and GUMBO 4. We have constructed a geologic history of the late-Jurassic/early-Cretaceous, beginning first with Louann

  14. Moho, LAB and crustal velocities underneath central-eastern Greenland

    Science.gov (United States)

    Kraft, H. A.; Thybo, H.

    2014-12-01

    Major parts of Greenland are covered with up to 3.4 km of ice. Due to logistical challenges connected to the ice only very sparse geophysical information is available. We present here results of the TopoGreenland project, which forms the first regional seismic experiment conducted on the Greenlandic ice shield. Our objective is to gain detailed information about the lithospheric structure and to connect it with topographic features, the recent substantial uplift and the earlier history of rifting and break-up in the region. We focus on a 200 km x 600 km large area in central-eastern Greenland, where 22 broadband seismometers were installed between June 2009 and May 2012. 10 of those were operating on the ice cap, 12 on bedrock. 16 of the stations were installed along a 600 km long profile at 70°N, from Scorsbysund to the centre of the ice cap. The remaining 6 stations covered a 200 km wide area north of this profile. In addition data from 6 permanent and long-term stations from the GLISN network were integrated. Here we present models from P- and S- receiver function (PRF, SRF) calculations and Rayleigh wave tomography. The RF calculations were used to map Moho and LAB depths and to have well constrained input parameters for the tomography. From the Rayleigh wave tomography we then obtain models for crustal shear-velocities. The PRF for the stations on the ice cap show multiples with very high amplitudes from within the ice, why we decided to derive Moho and LAB depths for those stations from SRF. The results will be compared with a seismic refraction profile acquired in the same region and then linked to topographic features like the uplift of the mountain chain in East Greenland.

  15. On the rheology of crustal rocks containing low melt fractions

    Science.gov (United States)

    Rosenberg, C. L.; Handy, M. R.

    2003-04-01

    A review and reinterpretation of older experimental data on the deformation of partially-melted granite reveals a non-linear strength decrease with increasing melt fractions. This decrease is characterised by two sharp discontinuities, each reflecting a dramatic change of strength within a limited range of melt fractions. A first discontinuity is shown by all experiments at melt fractions between 0.0 and 0.1. The change of strength within this range of melt fractions is the largest over the entire melting range. The second discontinuity occurs at higher melt fractions (0.4 to 0.6) and corresponds to the well known rheologically critical melt percentage (RCMP). In contrast to recent interpretations, we infer that the experimental data do indicate the occurrence of the RCMP, for crystallising as well as for melting rocks. However, the magnitude of the stress drop at the RCMP is negligible compared to the stress drop at melt fractions RCMP, at melt fractions >= 0.4, as proposed by several experimentalists. We suggest that the attainment of a melt fraction of 0.03 to 0.08 will control the large-scale localisation of deformation into partially-melted crustal layers, irrespective of the attainment of the RCMP. If the RCMP is achieved, however, the large-scale deformational response of the crust may not be different than that of a crust containing a melt fraction of 0.1. Instead, the RCMP controls localisation of flow within magmatic bodies, where it effects the internal dynamics of magma chambers.

  16. Munchausen syndrome mimicking psychiatric disease with concomitant genuine physical illness.

    Science.gov (United States)

    Almeida, Jaime; da Silva, Joaquim Alves; Xavier, Miguel; Gusmão, Ricardo

    2010-11-29

    Munchausen syndrome is a disorder in which patients intentionally produce symptoms mimicking physical or psychiatric illnesses with the aim to assume the sick role and to gain medical attention. Once a patient receives a Munchausen syndrome diagnosis every complaint made thence tends to be regarded with scepticism by clinical staff. However, it is possible that a bona fide illness, which might be disregarded, may coexist in these patients. We report a case of MS mimicking psychiatric disease with concomitant genuine acute physical illness. Despite the initial doubts about the veracity of the latter, due to its prompt recognition, treatment was successful.

  17. Crustal structure and active tectonics in the Eastern Alps

    DEFF Research Database (Denmark)

    Brückl, E.; Behm, M.; Decker, K.

    2010-01-01

    and underthusting of AD mantle below PA from southwest to northeast. The Moho fragmentation correlates well with major upper crustal structures and is supported by gravity, seismic, and geodetic data. An analysis of crustal thickening suggests that active convergence is associated with continued thrusting...... and lateral extrusion in the central Eastern Alps and thickening of the Adriatic indenter under the Southern Alps. According to the velocity relations at the triple junction, PA moves relative to EU and AD along ENE and SE striking faults, mainly by strike slip. An eastward directed extensional component...

  18. Towards Crustal Structure of Java Island (Sunda Arc) from Ambient Seismic Noise Tomography

    Science.gov (United States)

    Widiyantoro, Sri; Zulhan, Zulfakriza; Martha, Agustya; Saygin, Erdinc; Cummins, Phil

    2015-04-01

    In our previous studies, P- and S-wave velocity structures beneath the Sunda Arc were successfully imaged using a global data set and a nested regional-global tomographic method was employed. To obtain more detailed P- and S-wave velocity structures beneath Java, in the central part of the Sunda Arc, we then used local data sets, i.e. newline from the MErapi AMphibious EXperiment (MERAMEX) and the Meteorological, Climatological and Geophysical Agency (MCGA), as well as employed a double-difference technique for tomographic imaging. The results of the imaging show e.g. that P- and S-wave velocities are significantly reduced in the uppermost mantle beneath central Java. In order to obtain detailed crustal structure information beneath Java, the Ambient Noise Tomography (ANT) method was used. The application of this method to the MERAMEX data has produced a good crustal model beneath central Java. We continue our experiment to image crustal structure of eastern Java. We have used seismic waveform data recorded by 22 MCGA stationary seismographic stations and 25 portable seismographs installed for 2 to 8 weeks. The data were processed to obtain waveforms of cross-correlated noise between pairs of seismographic stations. Our preliminary results presented here indicate that the Kendeng zone, an area of low gravity anomaly, is associated with a low velocity zone. On the other hand, the southern mountain range, which has a high gravity anomaly, is related to a high velocity anomaly (as shown by our tomographic images). In future work we will install more seismographic stations in eastern Java as well as in western Java to conduct ANT imaging for the whole of Java Island. The expected result combined with the mantle velocity models resulting from our body wave tomography will allow for accurate location of earthquake hypocenters and determination of regional tectonic structures. Both of these are valuable for understanding seismic hazard in Java, the most densely populated

  19. Mimicked cartilage scaffolds of silk fibroin/hyaluronic acid with stem cells for osteoarthritis surgery: Morphological, mechanical, and physical clues

    Energy Technology Data Exchange (ETDEWEB)

    Jaipaew, Jirayut [Institute of Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Wangkulangkul, Piyanun [Institute of Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Department of Surgery, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Meesane, Jirut, E-mail: jirutmeesane999@yahoo.co.uk [Institute of Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Raungrut, Pritsana [Department of Biomedical Science, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Puttawibul, Puttisak [Institute of Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand); Department of Surgery, Faculty of Medicine, Prince of Songkla University, 15 Karnjanavanich Road, Hat Yai, Songkhla, Thailand 90110 (Thailand)

    2016-07-01

    Osteoarthritis is a critical disease that comes from degeneration of cartilage tissue. In severe cases surgery is generally required. Tissue engineering using scaffolds with stem cell transplantation is an attractive approach and a challenge for orthopedic surgery. For sample preparation, silk fibroin (SF)/hyaluronic acid (HA) scaffolds in different ratios of SF/HA (w/w) (i.e., 100:0, 90:10, 80:20, and 70:30) were formed by freeze-drying. The morphological, mechanical, and physical clues were considered in this research. The morphological structure of the scaffolds was observed by scanning electron microscope. The mechanical and physical properties of the scaffolds were analyzed by compressive and swelling ratio testing, respectively. For the cell experiments, scaffolds were seeded and cultured with human umbilical cord-derived mesenchymal stem cells (HUMSCs). The cultured scaffolds were tested for cell viability, histochemistry, immunohistochemistry, and gene expression. The SF with HA scaffolds showed regular porous structures. Those scaffolds had a soft and elastic characteristic with a high swelling ratio and water uptake. The SF/HA scaffolds showed a spheroid structure of the cells in the porous structure particularly in the SF80 and SF70 scaffolds. Cells could express Col2a, Agg, and Sox9 which are markers for chondrogenesis. It could be deduced that SF/HA scaffolds showed significant clues for suitability in cartilage tissue engineering and in surgery for osteoarthritis. - Highlights: • Silk fibroin/Hyaluronic acid was fabricated into mimicked scaffolds. • Mimicked scaffolds were incorporated with stem cells for chondrogenesis. • Mimicked scaffolds showed the clues for chondrogenic regulation. • Mimicked scaffolds had suitable performance for cartilage tissue engineering • Mimicked scaffolds showed promise for osteoarthritis surgery.

  20. Crustal Gravitational Potential Energy Change and Subduction Earthquakes

    Science.gov (United States)

    Zhu, P. P.

    2017-05-01

    Crustal gravitational potential energy (GPE) change induced by earthquakes is an important subject in geophysics and seismology. For the past forty years the research on this subject stayed in the stage of qualitative estimate. In recent few years the 3D dynamic faulting theory provided a quantitative solution of this subject. The theory deduced a quantitative calculating formula for the crustal GPE change using the mathematic method of tensor analysis under the principal stresses system. This formula contains only the vertical principal stress, rupture area, slip, dip, and rake; it does not include the horizontal principal stresses. It is just involved in simple mathematical operations and does not hold complicated surface or volume integrals. Moreover, the hanging wall vertical moving (up or down) height has a very simple expression containing only slip, dip, and rake. The above results are significant to investigate crustal GPE change. Commonly, the vertical principal stress is related to the gravitational field, substituting the relationship between the vertical principal stress and gravitational force into the above formula yields an alternative formula of crustal GPE change. The alternative formula indicates that even with lack of in situ borehole measured stress data, scientists can still quantitatively calculate crustal GPE change. The 3D dynamic faulting theory can be used for research on continental fault earthquakes; it also can be applied to investigate subduction earthquakes between oceanic and continental plates. Subduction earthquakes hold three types: (a) crust only on the vertical up side of the rupture area; (b) crust and seawater both on the vertical up side of the rupture area; (c) crust only on the vertical up side of the partial rupture area, and crust and seawater both on the vertical up side of the remaining rupture area. For each type we provide its quantitative formula of the crustal GPE change. We also establish a simplified model (called

  1. Calcific Tendinosis: A Potential Mimicker of Malignancy on PET

    OpenAIRE

    Vogel-Claussen, Jens; Morrison, William; Zoga, Adam; Bergin, Diane; Gopez, Angela; Fayad, Laura M.

    2015-01-01

    We report a case of a 53 year old female with breast cancer and elevated glucose activity at the left greater trochanter on PET imaging. Further imaging with CT and MRI showed that this focus of increased FDG activity on PET was calcific tendinosis of the gluteus medius tendon, which mimicked metastatic disease in this patient.

  2. Osteoid osteoma of the radial styloid mimicking de quervain tenosynovitis.

    Science.gov (United States)

    Chloros, George D; Themistocleous, George S; Papagelopoulos, Panayiotis J; Khaldi, Lubna; Efstathopoulos, Dimitrios G; Soucacos, Panayotis N

    2007-10-01

    A very unusual location of osteoid osteoma arising in the radial styloid is presented, which strongly mimicked de Quervain tenosynovitis, thereby resulting in the patient undergoing an additional unnecessary operation and a substantial delay of more than 2 years in diagnosis.

  3. Anterior sacral meningocele mimicking ovarian cyst: a case report.

    Science.gov (United States)

    Polat, Ahmet Veysel; Belet, Umit; Aydin, Ramazan; Katranci, Seckin

    2013-03-01

    Anterior sacral meningocele (ASM) is a rare congenital anomaly, characterized by herniation through a defect in the anterior aspect of the sacrum. We reported a case of ASM associated with neurofibromatosis, which was mimicking a complex ovarian cyst in ultrasonography. ASM can easily be misdiagnosed as an ovarian cyst and needle aspiration can cause intracranial hypotension syndrome or even death.

  4. Endometriosis of the meso-appendix mimicking appendicitis: A case ...

    African Journals Online (AJOL)

    Although appendicitis is largely a clinical diagnosis, on occasions diagnostic modalities may be needed to aid with the diagnosis. Despite the use of adjuncts and exploratory surgery, the diagnosis may not be clear until a histological diagnosis is achieved. Endometriosis of the appendix mimicking appendicitis is one of ...

  5. Mesenteric Panniculitis Mimicking Acute Pancreatitis: A Case Report ...

    African Journals Online (AJOL)

    Mesenteric Panniculitis Mimicking Acute Pancreatitis: A Case Report and Literature review. ... Treatment is empiric and surgical resection is sometimes attempted for definitive therapy. We report a case of a 77 year old man presenting with CT features of mesenteric panniculitis currently in remission. The aim is to highlight ...

  6. Cutaneous Silicone Granuloma Mimicking Breast Cancer after Ruptured Breast Implant

    Directory of Open Access Journals (Sweden)

    Waseem Asim Ghulam El-Charnoubi

    2011-01-01

    Full Text Available Cutaneous manifestations due to migration of silicone from ruptured implants are rare. Migrated silicone with cutaneous involvement has been found in the chest wall, abdominal wall, and lower extremities. We describe a case of cutaneous silicone granuloma in the breast exhibiting unusual growth mimicking breast cancer after a ruptured implant.

  7. Spinal MRI of vincristine neuropathy mimicking Guillain-Barre syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yun Woo; Yoon, Hye-Kyung; Cho, Jae Min [Department of Radiology, Samsung Medical Centre, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Kangnam-gu, Seoul 135-710 (Korea); Sung, Ki Woong [Department of Paediatrics, Samsung Medical Centre, Seoul 135-710 (Korea)

    2003-11-01

    A 4.3-year-old girl with acute leukaemia, who was being treated with chemotherapy (including vincristine), developed paraplegia. Spinal MRI showed diffusely enhancing nerve roots on contrast-enhanced images. Spinal fluid analysis showed a normal protein level. Vincristine neuropathy mimicking Guillain-Barre syndrome is thought to be the cause of the MRI abnormalities. (orig.)

  8. Endometriosis of the meso-appendix mimicking appendicitis: A case ...

    African Journals Online (AJOL)

    Endometriosis of the appendix mimicking appendicitis is one of these diagnoses described in several case reports. Endometriosis of the meso-appendix has been described in association with intussusception of the appendix in several case reports. However, to our knowledge, endometriosis of the meso-appendix ...

  9. Primary Papillary Mucinous Adenocarcinoma of the Ureter Mimicking Genitourinary Tuberculosis

    Directory of Open Access Journals (Sweden)

    Hanni Gulwani

    2010-01-01

    Full Text Available Primary adenocarcinomas of the renal pelvis and ureter are rare and account for less than 1% of all malignancies at this site. We report a case of primary papillary mucinous adenocarcinoma of the ureter that clinically mimicked genitourinary tuberculosis. Early diagnosis is important for the better outcome.

  10. Headache attributed to unruptured saccular aneurysm, mimicking hemicrania continua.

    Science.gov (United States)

    Vikelis, Michail; Xifaras, Michail; Magoufis, Georgios; Gekas, Georgios; Mitsikostas, Dimos Dimitrios

    2005-06-01

    Unruptured cerebral arterial aneurysms most often remain asymptomatic, but they may cause headache or other symptoms or signs. We describe herewith a case of headache attributed to an unruptured internal carotid artery aneurysm, clearly mimicking the phenotype of hemicrania continua. Potential pathophysiological explanations and recommendations for recognition of similar cases are discussed.

  11. A clinical challenging situation of Intra oral fibroma mimicking ...

    African Journals Online (AJOL)

    To differentiate the clinical mimicking situation of intra oral fibroma and pyogenic granuloma, surgical excision was done followed by histopathological examination reporting as intra oral fibroma. Fibroma is of smooth surfaced painless solid mass, occasionally nodular, with collagen and connective tissue histopathologically.

  12. Gastric Schistosomiasis Mimicking Gastric Cancer - A Case Report ...

    African Journals Online (AJOL)

    These parasites cause hepatosplenic and hepatointestinal schistosomiasis associated with significant morbidity and mortality especially in children and young people. We report a case of middle aged northern Nigerian farmer who had gastric schistosomiasis that mimicked an ulcerated gastric tumor at endoscopy with good ...

  13. Bilateral multiple pulmonary tuberculous nodules mimicking metastatic disease

    Energy Technology Data Exchange (ETDEWEB)

    Ariyuerek, Macit O.; Karcaaltincaba, Musturay E-mail: mkarcaal@hacettepe.edu.tr; Demirkazik, Figen B.; Akay, Hadi; Gedikoglu, Gokhan; Emri, Salih

    2002-10-01

    We present CT findings of a young woman who has bilateral pulmonary nodules mimicking metastases. Clinical presentation with active multiple pulmonary macronodules without cavitation responsive to treatment is an atypical manifestation of pulmonary tuberculosis. We reviewed the causes of multiple pulmonary nodules, role of radiological findings in differential diagnosis and parenchymal manifestations of pulmonary tuberculosis in this report.

  14. Crustal Variations in the Axial Low Velocity Zone Between the Siqueiros and Clipperton Transform Faults, East Pacific Rise

    Science.gov (United States)

    Wilcock, W. S.; Toomey, D. R.; Detrick, R. S.

    2002-12-01

    As part of the 1997 UNDERSHOOT seismic experiment, three rise-perpendicular profiles were collected across the East Pacific Rise between the Siqueiros and Clipperton transform faults. The southern line at 8°42'N lies at the center of an inflated segment south of the 9°03'N overlapping spreading center (OSC); the middle line at 9°18'N coincides with anomalously thick crust just to the north of the OSC; and the northern line at 9°50'N overlies a bathymetrically shallow segment near the site of recent eruptions. The lines extend at least 55 km off-axis and each comprises 200-400 airgun shots that were recorded by 6-7 seafloor receivers. We have used a two-dimensional tomography algorithm to invert crustal phases and Moho reflections for models of the P-wave velocity structure. For each line, we first inverted the non-rise crossing paths for off-axis structure and crustal thickness. We then interpolated the results to derive a starting model for axial inversions. Using a creeping method, we successively incorporated crustal phases that pass above the axial magma chamber (AMC), crustal phases that pass below the AMC, and Moho reflections. Since the ray geometry is two-dimensional, the width of the axial low velocity zone (LVZ) is not well resolved. We chose to squeeze the solutions by damping velocity perturbations at nodes that are more than 4-6 km off-axis. The root mean squared residuals are about 0.025 s for rise-crossing crustal phases and 0.03-0.04 s for sub-axial Moho reflections. The structure of the LVZ appears substantially different in the three models. Immediately beneath the AMC, the LVZ has the highest amplitude along the 9°50'N profile. In contrast, the LVZ in the lowermost crust has its largest amplitude along the 9°18'N profile where the crustal thickness requires that the melt supply is highest. The lower crustal LVZ beneath the 9°50'N profile is less pronounced than at the other two sites and is significantly skewed to the east. The differences

  15. Crustal growth at active continental margins: Numerical modeling

    NARCIS (Netherlands)

    Vogt, Katharina|info:eu-repo/dai/nl/370618947; Gerya, Taras; Castro, Antonio

    The dynamics and melt sources for crustal growth at active continental margins are analyzed by using a 2D coupled petrological–thermomechanical numerical model of an oceanic-continental subduction zone. This model includes spontaneous slab retreat and bending, dehydration of subducted crust, aqueous

  16. Gravity anomalies, crustal structure and rift tectonics at the Konkan ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 121; Issue 3. Gravity anomalies, crustal structure and rift tectonics at the Konkan and Kerala basins, western continental margin of India. Sheena V Dev M Radhakrishna Shyam Chand C Subrahmanyam. Volume 121 Issue 3 June 2012 pp 813-822 ...

  17. Crustal structure of the Eastern Alps and their foreland

    DEFF Research Database (Denmark)

    Grad, M.; Brückl, E.; Majdanski, M.

    2009-01-01

    The subject of this paper concerns the seismic modelling of the crustal structure in the transition zone from the Bohemian Massif, across the Molasse basin and the Eastern Alps to the Southern Alps, mainly on the territory of Austria. The CEL10/Alp04 profile crosses the triple point of the Europe...

  18. THE CRUSTAL STRUCTURE OF ELLESMERE ISLAND FROM RECEIVER FUNCTION MODELLING

    DEFF Research Database (Denmark)

    Schiffer, Christian; Stephenson, Randell Alexander; Oakey, Gordon

    Island is poorly investigated, which leads to large ambiguity and uncertainty of geological interpretations, especially on a crustal and lithospheric scale. To fill this information gap a seismological survey (ELLITE) was performed. A north-south oriented and ~520 km long array, consisting of 7 broadband...

  19. Using Crustal Fluids to Peer Into the Subseafloor Microbial Habitat

    Science.gov (United States)

    Huber, J. A.

    2008-12-01

    In hard rock seafloor environments, fluids emanating from the basement are one of the best windows into the subseafloor and its resident microbial community. These low-temperature crustal fluids are ubiquitous at both active hydrothermal systems and ridge flank environments. Over the last 15 years, studies of the microbial communities in crustal fluids from eruptive events, drill holes, ridge flanks, and hydrothermal seamounts have revealed a phylogenetically and physiologically diverse microbial community, representing a wide spectrum of thermal tolerances and metabolic strategies from both the subseafloor and the deep sea. In addition, emerging technologies in seafloor sampling capacity and microbial ecology are rapidly increasing our ability to study this difficult habitat. This presentation will provide an overview of what we have learned about the population structure, genomic repertoire, and physiological function of microbes in crustal fluids and what the future holds for subseafloor biosphere research. Data will be integrated with geochemical measurements in crustal environments to better define the subseafloor habitat and its resident microbial community.

  20. Crustal thickness of Turkey determined by receiver function

    Science.gov (United States)

    Tezel, Timur; Shibutani, Takuo; Kaypak, Bülent

    2013-10-01

    Two-hundred and sixty-seven teleseismic events with a moment magnitude greater than 5.5 which occurred between January 2005 and October 2010 were analyzed to determine the Moho depth variation beneath Turkey by using the Receiver Function (RF) technique. The RF technique was applied to 120 broadband seismic stations, which were already deployed in the area permanently by the Kandilli Observatory and Earthquake Research Institute (KOERI) and the Disaster and Emergency Management Presidency (AFAD). The RFs were stacked considering back-azimuth, slowness and waveform similarities to enhance the signal/noise ratio. The genetic algorithm (GA) was used to obtain both 1-D shear-wave speed model and the Moho depth beneath each seismic station. A data set consisting of 112 shear-speed models derived from RFs revealed the crustal structure of Turkey. For imaging, several 2-D profiles of depth-migrated RFs were constructed to delineate the fine crustal structure. The Moho discontinuity is clearly seen on all profiles and the mid-crustal velocity discontinuity within the crust is observed in some profiles. The depth of the Moho varies between 24 and 48 km. The thinnest crustal thickness is located on the coast of Western Turkey, and the deepest Moho boundary is observed in Eastern Turkey. The shear wave velocities vary between 4.0 km/s and 4.5 km/s in the uppermost mantle beneath Turkey.

  1. A proposed concept for a crustal dynamics information management network

    Science.gov (United States)

    Lohman, G. M.; Renfrow, J. T.

    1980-01-01

    The findings of a requirements and feasibility analysis of the present and potential producers, users, and repositories of space-derived geodetic information are summarized. A proposed concept is presented for a crustal dynamics information management network that would apply state of the art concepts of information management technology to meet the expanding needs of the producers, users, and archivists of this geodetic information.

  2. Studying sub-crustal reflectors in SW-Spain with wide-angle profiles

    Science.gov (United States)

    Palomeras, Imma; Ayarza, Puy; Carbonell, Ramon; Afonso, JuanCarlos; Diaz, Jordi

    2017-04-01

    It is nowadays widely accepted that the mantle is highly heterogeneous and has lithologies that are capable of giving impedance enough to be observed in seismic data. Nevertheless, observing those impedance contrasts at mantle depths is a challenging problem. SW Iberia has been sampled by different deep vertical reflection and wide-angle reflection/refraction experiments ILIHA, IBERSEIS, and ALCUDIA, and hence provide a good opportunity to study seismically sub-crustal reflectors. These datasets have imaged a conspicuous sub-crustal reflector. This mantle reflector was first identified on the IBERSEIS wide angle reflection shot-gathers at large offsets (above 180 km). It was modeled as a boundary located between 61-72 km depth with a Vp increase from 8.2 km/s to 8.3 km/s. The fact that this reflector was not identified in the coincident vertical incidence dataset led us to interpret it as a gradient zone. A correlation with the 'Hales gradient zone', i.e. the boundary between spinel and garnet peridotites, was our preferred interpretation. The ALCUDIA experiment also shows prominent sub-crustal arrivals with the same characteristics as those observed in the IBERSEIS wide-angle data. However, these reflections also appear, locally and at 19 s TWT, in the vertical incidence dataset. In addition, the ALCUDIA wide-angle dataset shows a deeper reflector that maybe preliminarily associated with mantle anisotropy or even with the lithosphere-asthenosphere boundary. Both upper mantle reflectors are modeled at 65 km and 100 km depth, respectively, shallowing to the north to 55 km and 90 km depth. Integration of the information provided by the IBERSEIS and ALCUDIA datasets with older and lower resolution data from the ILIHA project, where three sub-crustal phases were identified in SW Iberia, allows us to conclude that, in this area, mantle reflectivity is outstanding. Also, modeling of all the datasets contributes to map, at a regional scale, the Hales discontinuity or

  3. Coupled interactions between volatile activity and Fe oxidation state during arc crustal processes

    Science.gov (United States)

    Humphreys, Madeleine C.S.; Brooker, R; Fraser, D.C.; Burgisser, A; Mangan, Margaret T.; McCammon, C

    2015-01-01

    Arc magmas erupted at the Earth’s surface are commonly more oxidized than those produced at mid-ocean ridges. Possible explanations for this high oxidation state are that the transfer of fluids during the subduction process results in direct oxidation of the sub-arc mantle wedge, or that oxidation is caused by the effect of later crustal processes, including protracted fractionation and degassing of volatile-rich magmas. This study sets out to investigate the effect of disequilibrium crustal processes that may involve coupled changes in H2O content and Fe oxidation state, by examining the degassing and hydration of sulphur-free rhyolites. We show that experimentally hydrated melts record strong increases in Fe3+/∑Fe with increasing H2O concentration as a result of changes in water activity. This is relevant for the passage of H2O-undersaturated melts from the deep crust towards shallow crustal storage regions, and raises the possibility that vertical variations in fO2 might develop within arc crust. Conversely, degassing experiments produce an increase in Fe3+/∑Fe with decreasing H2O concentration. In this case the oxidation is explained by loss of H2 as well as H2O into bubbles during decompression, consistent with thermodynamic modelling, and is relevant for magmas undergoing shallow degassing en route to the surface. We discuss these results in the context of the possible controls on fO2 during the generation, storage and ascent of magmas in arc settings, in particular considering the timescales of equilibration relative to observation as this affects the quality of the petrological record of magmatic fO2.

  4. Variation in Crustal Structure of the Lesser Caucasus Region from Teleseismic Receiver Functions

    Science.gov (United States)

    Lin, C. M.; Tseng, T. L.; Huang, B. S.; Legendre, C. P.; Karakhanian, A.

    2016-12-01

    The Caucasus, including the mountains of Greater and Lesser Caucasus, is formed by the continental collision between Arabia and Eurasia. The crustal thickness for this region was mostly constrained by joint analysis of receiver functions and surface waves. Although the thickest value of 52 km was reported under the Lesser Caucasus, the resolution of earlier studies were often limited by sparse array. Large gradient across Moho also makes the definition of Moho difficult. Moreover, higher value of the Vp/Vs ratio is commonly reported in the northeastern Turkey but no estimates had been made for the Caucasus. To further investigate the detail structure around the Lesser Caucasus, we constructed a new seismic network in Georgia and Armenia. We also include other broadband stations to enhance the coverage. The average interval in the Lesser Caucasus is roughly 30 km, much denser than any previous experiments. We selected P-waveforms from teleseismic earthquakes during the operation (January 2012 - June 2016) to calculate receiver functions and then estimate the crustal thickness (H) and Vp/Vs ratio (k) with the H-k stacking technique. Our preliminary results show that Moho depth increases from 40 km under the northeastern Turkey to 50 km beneath northern Georgia, no station with Moho deeper than 50 km under the Lesser Caucasus. The Vp/Vs ratios in the northeastern Anatolian plateau are around 1.8, which is slightly higher than the average of global continents but consistent with the previous estimates. Further to the east, some stations show anomalously higher Vp/Vs ratio in central & southern Armenia that may be associated with Holocene volcanism. In the future, we plan to join locally measured dispersion curves to invert the velocity model without velocity-depth trade-off. We expect to resolve the velocity variations of the crust beneath this region in small scale that may be tied to the continental collision and surface volcanism. Keywords: Caucasus, receiver

  5. 3-D crustal velocity structure of western Turkey: Constraints from full-waveform tomography

    Science.gov (United States)

    Çubuk-Sabuncu, Yeşim; Taymaz, Tuncay; Fichtner, Andreas

    2017-09-01

    The Sea of Marmara and western Turkey are characterized by intense seismicity and crustal deformation due to transition tectonics between the North Anatolian Fault Zone (NAFZ) and the extensional Aegean. Seismic imaging of the crust and uppermost mantle in W-NW Turkey is crucial to obtain a better understanding of its seismotectonics and geodynamics. So far, the Sea of Marmara and surroundings were considered in various active and passive seismic experiments providing significant information on crustal properties. Here, we further investigate the 3-D seismic velocity structure in this rapidly deforming region using non-linear full-waveform tomography based on the adjoint method. Our model is constrained by complete waveforms of 62 regional earthquakes (epicentral distance data uncertainties. Furthermore, quantitative resolution analyses yield 15 to 35 km horizontal resolution lengths in the shallow and deep crust beneath well-covered areas of W-NW Turkey. Our full-waveform tomography results indicate the presence of strong lateral and vertical velocity variations (2.55 ≤ VS ≤ 4.0 km/s) down to depths of ∼35 km. The seismic velocity distribution is characteristic of highly deformed and distributed crustal features along major fault zones (e.g. NAFZ and its branches), historic and recent regional volcanism (e.g. Kula volcanic province), and metamorphic core complex developments (e.g. Menderes and Kazdağ massifs). Radial anisotropy is very strong (around 20%) throughout the crust, further attesting to strong deformation and heterogeneity. Generally, our 3-D model is overall consistent with the active tectonics of western Turkey.

  6. Immunoglobulin G4 -related kidney disease: A comprehensive pictorial review of the imaging spectrum, Mimickers, and clinicopathological characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Ni Eun; Kim, Jin Hee; Byun, Jae Ho; Lee, Seung Soo; Kim, Hyoung Jung; Lee, Moon Gyu [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2015-10-15

    Immunoglobulin G4 (IgG4)-related kidney disease (IgG4-KD) has recently been demonstrated to be an important part of IgG4-related sclerosing disease (IgG4-SD). However, since IgG4-KD is still relatively unfamiliar to radiologists and physicians as compared to IgG4-SD involving other organs, it could, therefore, be easily missed. In this article, we present a comprehensive pictorial review of IgG4-KD with regards to the imaging spectrum, mimickers, and clinicopathologic characteristics, based on our clinical experience with 48 patients during the past 13 years, as well as a literature review. Awareness of the broad imaging spectrum of IgG4-KD and differential diagnosis from its mimickers will thus facilitate its early diagnosis and treatment.

  7. Cavernous haemangioma mimicking as clitoral hypertrophy

    Directory of Open Access Journals (Sweden)

    Sajid Nayyar

    2014-01-01

    Full Text Available Haemangioma is the most common benign neoplasm of infantile age. It is most commonly located in head and neck region, trunk and extremities but very rarely it can be located at clitoris. However, it is very important to differentiate clitoral haemangioma from enlargement of the clitoris secondary to androgen excess. Only four cases of clitoromegaly caused by cavernous haemangioma have been reported in the literature so far. Herein, we report our experience with a 10-year-old girl who presented with clitoromegaly and normal hormonal assay that turned out to be clitoral cavernous haemangioma after histopathological examination of the clitoral mass.

  8. Seasonal Mass Changes and Crustal Vertical Deformations Constrained by GPS and GRACE in Northeastern Tibet

    Directory of Open Access Journals (Sweden)

    Yuanjin Pan

    2016-08-01

    Full Text Available Surface vertical deformation includes the Earth’s elastic response to mass loading on or near the surface. Continuous Global Positioning System (CGPS stations record such deformations to estimate seasonal and secular mass changes. We used 41 CGPS stations to construct a time series of coordinate changes, which are decomposed by empirical orthogonal functions (EOFs, in northeastern Tibet. The first common mode shows clear seasonal changes, indicating seasonal surface mass re-distribution around northeastern Tibet. The GPS-derived result is then assessed in terms of the mass changes observed in northeastern Tibet. The GPS-derived common mode vertical change and the stacked Gravity Recovery and Climate Experiment (GRACE mass change are consistent, suggesting that the seasonal surface mass variation is caused by changes in the hydrological, atmospheric and non-tidal ocean loads. The annual peak-to-peak surface mass changes derived from GPS and GRACE results show seasonal oscillations in mass loads, and the corresponding amplitudes are between 3 and 35 mm/year. There is an apparent gradually increasing gravity between 0.1 and 0.9 μGal/year in northeast Tibet. Crustal vertical deformation is determined after eliminating the surface load effects from GRACE, without considering Glacial Isostatic Adjustment (GIA contribution. It reveals crustal uplift around northeastern Tibet from the corrected GPS vertical velocity. The unusual uplift of the Longmen Shan fault indicates tectonically sophisticated processes in northeastern Tibet.

  9. A pulmonary paragonimiasis case mimicking metastatic pulmonary tumor.

    Science.gov (United States)

    Kim, Ki Uk; Lee, Kwangha; Park, Hye-Kyung; Jeong, Yeon Joo; Yu, Hak Sun; Lee, Min Ki

    2011-03-01

    Pulmonary paragonimiasis is a relatively rare cause of lung disease revealing a wide variety of radiologic findings, such as air-space consolidation, nodules, and cysts. We describe here a case of pulmonary paragonimiasis in a 27-year-old woman who presented with a 2-month history of cough and sputum. Based on chest computed tomography (CT) scans and fluorodeoxyglucose positron emission tomography (FDG-PET) findings, the patient was suspected to have a metastatic lung tumor. However, she was diagnosed as having Paragonimus westermani infection by an immunoserological examination using ELISA. Follow-up chest X-ray and CT scans after chemotherapy with praziquantel showed an obvious improvement. There have been several reported cases of pulmonary paragonimiasis mimicking lung tumors on FDG-PET. However, all of them were suspected as primary lung tumors. To our knowledge, this patient represents the first case of paragonimiasis mimicking metastatic lung disease on FDG-PET CT imaging.

  10. A case of ovarian paragonimiasis mimicking ovarian carcinoma.

    Science.gov (United States)

    Tantipalakorn, Charuwan; Khunamornpong, Surapan; Tongsong, Theera

    2014-01-01

    The purpose of this report is to describe ovarian paragonimiasis, a rare form of lung fluke infestation, mimicking ovarian cancer. A 47-year-old Thai woman presented with a pelvic mass. Imaging suggested ovarian cancer with pulmonary and hepatic metastases. She was scheduled for complete surgical staging. However, a frozen section revealed Paragonimus eggs in the enlarged ovarian mass. A total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed instead of complete staging. All other lesions were also proven later to be Paragonimus infestation. Postoperative treatment with antiparasitic drugs resulted in dramatic improvement, with nearly complete resolution of all lesions at 4 months of follow-up. This is an unusual case of ovarian paragonimiasis mimicking ovarian cancer, which is instructive and informative for differential diagnoses of pelvic masses. © 2014 S. Karger AG, Basel.

  11. Crustal displacements in Greenland caused by ice mass variability

    DEFF Research Database (Denmark)

    Nielsen, Karina

    The climate of the Earth is changing. A consequence of this is observed at the polar regions such as Greenland, where the ice sheet is melting with an increasing rate. The unloading of ice causes the Earth to respond elastically in terms of uplift and an outward horizontal deformation of the crust....... This motion can be measured by permanent Global Positioning System (GPS) receivers. Hence, the rates of crustal displacement are an indirect measure of the occurring mass changes. Currently, 55 GPS sites are located around the margin of the Greenland ice sheet, continuously providing information about...... the state of the ice sheet. However, the Earth is also adjusting viscoelastically to variations in the late Pleistocene ice sheets i.e. glacial isostatic adjustment (GIA). Observed rates of crustal displacement therefor contain signals from both past and present ice mass variations. Hence, to interpret...

  12. Compositional stratigraphy of crustal material from near-infrared spectra

    Science.gov (United States)

    Pieters, Carle M.

    1987-01-01

    An Earth-based telescopic program to acquire near-infrared spectra of freshly exposed lunar material now contains data for 17 large impact craters with central peaks. Noritic, gabbroic, anorthositic and troctolitic rock types can be distinguished for areas within these large craters from characteristic absorptions in individual spectra of their walls and central peaks. Norites dominate the upper lunar crust while the deeper crustal zones also contain significant amounts of gabbros and anorthosites. Data for material associated with large craters indicate that not only is the lunar crust highly heterogeneous across the nearside, but that the compositional stratigraphy of the lunar crust is nonuniform. Crustal complexity should be expected for other planetary bodies, which should be studied using high spatial and spectral resolution data in and around large impact craters.

  13. Detailed Northern Anatolian Fault Zone crustal structure from receiver functions

    Science.gov (United States)

    Cornwell, D. G.; Kahraman, M.; Thompson, D. A.; Houseman, G. A.; Rost, S.; Turkelli, N.; Teoman, U.; Altuncu Poyraz, S.; Gülen, L.; Utkucu, M.

    2013-12-01

    We present high resolution images derived from receiver functions of the continental crust in Northern Turkey that is dissected by two fault strands of the Northern Anatolian Fault Zone (NAFZ). The NAFZ is a major continental strike-slip fault system that is comparable in length and slip rate to the San Andreas Fault Zone. Recent large earthquakes occurred towards the western end of the NAFZ in 1999 at Izmit (M7.5) and Düzce (M7.2). As part of the multi-disciplinary Faultlab project, we aim to develop a model of NAFZ crustal structure and locate deformation by constraining variations in seismic properties and anisotropy in the upper and lower crust. The crustal model will be an input to test deformation scenarios in order to match geodetic observations from different phases of the earthquake loading cycle. We calculated receiver functions from teleseismic earthquakes recorded by a rectangular seismometer array spanning the NAFZ with 66 stations at a nominal inter-station spacing of 7 km and 7 additional stations further afield. This Dense Array for North Anatolia (DANA) was deployed from May 2012 until September 2013 and we selected large events (Mw>5.5) from the high quality seismological dataset to analyze further. Receiver functions were calculated for different frequency bands then collected into regional stacks before being inverted for crustal S-wave velocity structure beneath the entire DANA array footprint. In addition, we applied common conversion point (CCP) migration using a regional velocity model to construct a migrated 3D volume of P-to-S converted and multiple energy in order to identify the major crustal features and layer boundaries. We also performed the CCP migration with transverse receiver functions in order to identify regions of anisotropy within the crustal layers. Our preliminary results show a heterogeneous crust above a flat Moho that is typically at a depth of 33 km. We do not observe a prominent step in the Moho beneath the surface

  14. Mimicking Biological Design and Computing Principles in Artificial Olfaction

    Science.gov (United States)

    2011-01-01

    Biology has inspired solutions to many engineering problems, including those encountered in chemical sensing. Modern approaches to chemical sensing have been based on the biological principle of combining cross-selective chemical sensors with a pattern recognition engine to identify odors. Here, we review some recent advances made in mimicking biological design and computing principles to develop an electronic nose. The resulting technology will have important applications in fundamental biological research, as well as in industrial, security, and medical domains. PMID:22081790

  15. Splenosis with lower gastrointestinal bleeding mimicking colonical gastrointestinal stromal tumour

    OpenAIRE

    Xiao, Shuo-meng; Xu, Rui; Tang, Xiao-li; Ding, Zhi; Li, Ji-man; Zhou, Xiang

    2017-01-01

    Background Splenosis refers to the heterotopic transplantation of splenic tissue following splenic trauma or splenectomy. Splenosis is typically asymptomatic and is often identified incidentally. Case presentation We report a case of splenosis with colon and stomach invasion presenting as lower gastrointestinal bleeding and mimicking colonic gastrointestinal stromal tumour (GIST). The importance of suspicion for splenosis in patients with a history of splenic injury should be highlighted. Com...

  16. Cartilage Delamination Flap Mimicking a Torn Medial Meniscus.

    Science.gov (United States)

    Jonathan, Gan Zhi-Wei; Bin Abd Razak, Hamid Rahmatullah; Amit Kanta, Mitra

    2016-01-01

    We report a case of a chondral delamination lesion due to medial parapatellar plica friction syndrome involving the medial femoral condyle. This mimicked a torn medial meniscus in clinical and radiological presentation. Arthroscopy revealed a chondral delamination flap, which was debrided. Diagnosis of chondral lesions in the knee can be challenging. Clinical examination and MRI have good accuracy for diagnosis and should be used in tandem. Early diagnosis and treatment of chondral lesions are important to prevent progression to early osteoarthritis.

  17. An abdominal tuberculosis case mimicking an abdominal mass

    African Journals Online (AJOL)

    An abdominal tuberculosis case mimicking an abdominal mass. Derya Erdog˘ an a. , Yasemin Ta ¸scı Yıldız b. , Esin Cengiz Bodurog˘lu c and Naciye Go¨nu¨l Tanır d. Abdominal tuberculosis is rare in childhood. It may be difficult to diagnose as it mimics various disorders. We present a 12-year-old child with an unusual ...

  18. Degenerated uterine leiomyomas mimicking malignant bilateral ovarian surface epithelial tumors

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Yi Boem Ha; Lee, Hae Kyung; Lee, Min Hee; Choi, Seo Youn; Chung, Soo Ho [Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon (Korea, Republic of)

    2017-07-15

    Uterine leiomyomas are the most common benign uterine neoplasms. Undegenerated uterine leiomyomas are easily recognizable by the typical imaging findings on radiologic studies. However, degenerated fibroids can have unusual and variable appearances. The atypical appearances due to degenerative changes may cause confusion in diagnosis of leiomyomas. In this article, we report a case of a patient with extensive cystic and myxoid degeneration of uterine leiomyoma, mimicking malignant bilateral ovarian surface epithelial tumors.

  19. Mimicking Nonequilibrium Steady States with Time-Periodic Driving

    Science.gov (United States)

    2016-08-29

    biochemical reactions , can be effectively mimicked by a constrained periodic driving. DOI: 10.1103/PhysRevX.6.021022 Subject Areas: Statistical...error rates in biochemical reactions such as protein synthesis. The system in kinetic proofreading is described by a discrete-state continuous-time... concentrations are constantly maintained out of equilibrium. Such a coupling modifies the Arrhenius rates : Denoting the rate matrix now by R (as it is not

  20. Amiodarone-induced pulmonary toxicity mimicking metastatic lung disease.

    Science.gov (United States)

    Patel, P; Honeybourne, D; Watson, R D

    1987-05-01

    A 65 year old man developed atrial arrhythmias secondary to a congestive cardiomyopathy which were resistant to quinidine and disopyramide. Amiodarone controlled the paroxysmal atrial tachycardia but 4 months after starting the drug he developed increasing dyspnoea and radiological changes highly suggestive of metastatic lung disease. Lung biopsy showed change of drug-induced pneumonitis and 4 months after stopping amiodarone his symptoms resolved and the chest X-ray had cleared. Amiodarone may cause pulmonary toxicity mimicking metastatic lung disease.

  1. Osteofibrous dysplasia of clavicle clinically mimicking chronic osteomyelitis

    Directory of Open Access Journals (Sweden)

    Nirmal Raj Gopinathan

    2016-01-01

    Full Text Available Osteofibrous dysplasia or ossifying fibroma is an uncommon benign fibro-osseous lesion of childhood, commonly described in the maxilla and the mandible. Among long bones, it usually presents in the tibia as a painless swelling or anterior bowing. Ossifying fibroma of clavicle has never been reported in English literature, to the best of our knowledge. Here, we would like to present an unusual case of osteofibrous dysplasia of clavicle clinically mimicking chronic osteomyelitis.

  2. Juvenile Myelomonocytic Leukemia in a Premature Neonate Mimicking Neonatal Sepsis

    Directory of Open Access Journals (Sweden)

    Ming-Luen Lee

    2016-04-01

    Full Text Available Juvenile myelomonocytic leukemia (JMML is a rare hematologic malignancy in children. Its presentations include anemia, thrombocytopenia, monocytosis, skin rash, marked hepatomegaly, and/or splenomegaly. Fever and respiratory involvement are common. Here, we report a case of a premature neonate with initial symptoms of respiratory distress. She gradually developed clinical manifestations of JMML that mimicked neonatal sepsis. Three weeks after birth, JMML was diagnosed. This is the first reported case of JMML presenting in a premature infant in Taiwan.

  3. Primary Ovarian and Pararectal Hydatid Cysts Mimicking Pelvic Endometriosis

    Directory of Open Access Journals (Sweden)

    Mehmet Karaman

    2012-12-01

    Full Text Available We report a case of 48-year-old woman with multiple hydatid cysts in pararectal region and right paraovarian localization with an unusual sonographic and computed tomographic presentation mimicking a pelvic endometriosis. During laparotomy, multiple pararectal and right ovarian cysts resembling endometriosis were resected. Pathologic examination gives the diagnosis of hydatid cysts. Retrospectively, we investigate the primary infection but the patient had no history of hepatic and liver involvement, it is a case of primary infection

  4. The nature of crustal reflectivity at the southwest Iberian margin

    Science.gov (United States)

    Buffett, G. G.; Torne, M.; Carbonell, R.; Melchiorre, M.; Vergés, J.; Fernàndez, M.

    2017-11-01

    Reprocessing of multi-channel seismic reflection data acquired over the northern margin of the Gulf of Cádiz (SW Iberian margin) places new constraints on the upper crustal structure of the Guadalquivir-Portimão Bank. The data presented have been processed with optimized stacking and interval velocity models, a better approach to multiple attenuation, preserved amplitude information to derive the nature of seismic reflectivity, and accurate time-to-depth conversion after migration. The reprocessed data reveal a bright upper crustal reflector just underneath the Paleozoic basement that spatially coincides with the local positive free-air gravity high called the Gulf of Cádiz Gravity High. To investigate the nature of this reflector and to decipher whether it could be associated with pieces of mantle material emplaced at upper crustal levels, we calculated its reflection coefficient and compared it to a buried high-density ultramafic body (serpentinized peridotite) at the Gorringe Bank. Its reflection coefficient ratio with respect to the sea floor differs by only 4.6% with that calculated for the high-density ultramafic body of the Gorringe Bank, while it differs by 35.8% compared to a drilled Miocene limestone unconformity. This means that the Gulf of Cádiz reflector has a velocity and/or density contrast similar to the peridotite at the Gorringe Bank. However, considering the depth at which it is found (between 2.0 and 4.0 km) and the available geological information, it seems unlikely that the estimated shortening from the Oligocene to present is sufficient to emplace pieces of mantle material at these shallow levels. Therefore, and despite the similarity in its reflection coefficient with the peridotites of the Gorringe Bank, our preferred interpretation is that the upper crustal Gulf of Cádiz reflector represents the seismic response of high-density intracrustal magmatic intrusions that may partially contribute to the Gulf of Cádiz Gravity High.

  5. Crustal radial anisotropy beneath Cameroon from ambient noise tomography

    Science.gov (United States)

    Ojo, Adebayo Oluwaseun; Ni, Sidao; Li, Zhiwei

    2017-01-01

    To increase the understanding of crustal deformation and crustal flow patterns due to tectonic processes in Cameroon, we study the lateral variability of the crustal isotropic velocity and radial anisotropy estimated using Ambient Noise Tomography (ANT). Rayleigh and Love wave Noise Correlation Functions (NCFs) were retrieved from the cross-correlation of seismic ambient noise data recorded in Cameroon, and phase velocities at periods of 8 to 30 s were measured to perform surface wave tomography. Joint inversion of Rayleigh and Love wave data for isotropic velocity models could not fit the observed dispersions simultaneously. We attribute the Love-Rayleigh discrepancy to the presence of radial anisotropy in the crust and estimated its magnitude. Our 3-D radial anisotropic model reveals the spatial variation of strong to weak positive (Vsh > Vsv) and negative (Vsv > Vsh) radial anisotropy in the crust. We observe negative radial anisotropy in the upper crust that is associated mainly with the location of a previously reported mantle plume. The anisotropy could be attributed to the vertical alignment of fossil microcracks or metamorphic foliations due to the upwelling of plume material. A strong positive radial anisotropy is centered at the location of an inferred boundary between the Congo Craton and the Oubanguides Belt that might be related to the preferred orientation of crustal anisotropic minerals associated with shearing in this fault zone. The middle crust is characterized by a widespread negative radial anisotropy that is likely caused by the flow-induced alignment of anisotropic minerals that crystallized during magma intrusion. The magnitude of the radial anisotropy varies systematically from predominantly negative in the middle crust to positive in the lower crust. The imaged patterns of the isotropic velocity and radial anisotropy are consistent with previous studies and agree with regional tectonics.

  6. Crustal response to lithosphere evolution:examples from Eurasia

    OpenAIRE

    Artemieva, Irina; Thybo, Hans; Cherepanova, Yulia; Chemia, Zurab

    2012-01-01

    We present a new model for the structure of the crust in an area which stretches from the North Atlantic region in the west to the Verkhoyansk Ridge in the east and encompasses Greenland, Iceland, most of Europe, West Siberian basin, and the Siberian cratons. The model is based on critically assessed results from various seismic studies, including reflection and refraction profiles and receiver function studies. The region includes a nearly continuous age record for crustal evolution over ca....

  7. History of crustal recycling recorded in transition zone diamonds

    Science.gov (United States)

    Pearson, D. G.; Stachel, T.; Palot, M.; Ickert, R. B.

    2015-12-01

    The Earth's transition zone (TZ) is a key region within the Earth that, from seismology, may be composed of a mixture of relatively primitive material together with the products of crustal recycling throughout the history of plate tectonics. The only samples of the TZ come in the form of inclusions in diamonds, that, for the most-part are retrogressed lower pressure equivalents of their precursor phases that formed at depth. Recent work by our group and others [1] on transition zone diamonds indicate that both peridotite and eclogitic paragenesis diamonds may record the products of crustal recycling. In-situ ion probe nitrogen and carbon isotopic measurements indicate the crystallisation of TZ diamonds from fluids bearing crustal signatures, of both oxidised and reduced forms. At the same time, majoritic garnets record extreme oxygen isotope compositions that track the interaction of oceanic crust with seawater at low temperature [2]. Such an origin is consistent with the few measured Sr-Nd isotope compositions of majorite garnet inclusions which resemble depleted MORB [3]. We have found considerably more enriched Sr isotope compositions (87Sr/86S ranging to > 0.8) in CaSiO3 inclusions that are from deep asthenosphere to TZ depths, supporting an origin that includes incorporation of recycled crustal sediment, in addition to the basaltic oceanic crust required to explain the phase equilibria [4]. Lastly, the discovery of hydrous ringwoodite in a diamond [5] containing more water than is soluble at the lower TZ adiabat indicates the possible role of recycling in transporting water as well as carbon into the TZ via a cool thermally unequilibrated slab. [1] Thomson et al (2014) CMP, 168, 1081. [2] Ickert et al (2015) Geochemical perspectives Letters, 1, 65-74. [3] Harte & Richardson (2011) Gondwana Research, 21, 236-235. [4] Walter et al. (2011) Science, 334, 54-57.[Pearson et al. (2014) Nature, 507, 221-224.

  8. Upper mantle and crustal structure of the East Greenland Caledonides

    DEFF Research Database (Denmark)

    Schiffer, Christian; Balling, N.; Jacobsen, B. H.

    Function study based on an average of 36 events per station reveals a clear eastward dipping high-velocity structure underneath the study area. The geophysical character, supported by synthetic modelling, is consistent with a 10 km thick subducted slab of eclogitized oceanic crust. This might be the key...... present selected results from on-going detailed studies of the crustal and upper mantle, including a Receiver Function inversion, seismic P-wave travel time tomography and gravity modelling....

  9. Dengue fever mimicking acute appendicitis: A case report.

    Science.gov (United States)

    McFarlane, M E C; Plummer, J M; Leake, P A; Powell, L; Chand, V; Chung, S; Tulloch, K

    2013-01-01

    Dengue fever is an acute viral disease, which usually presents as a mild febrile illness. Patients with severe disease present with dengue haemorrhagic fever or dengue toxic shock syndrome. Rarely, it presents with abdominal symptoms mimicking acute appendicitis. We present a case of a male patient presenting with right iliac fossa pain and suspected acute appendicitis that was later diagnosed with dengue fever following a negative appendicectomy. A 13-year old male patient presented with fever, localized right-sided abdominal pain and vomiting. Abdominal ultrasound was not helpful and appendicectomy was performed due to worsening abdominal signs and an elevated temperature. A normal appendix with enlarged mesenteric nodes was found at surgery. Complete blood count showed thrombocytopenia with leucopenia. Dengue fever was now suspected and confirmed by IgM enzyme-linked immunosorbent assay against dengue virus. This unusual presentation of dengue fever mimicking acute appendicitis should be suspected during viral outbreaks and in patients with atypical symptoms and cytopenias on blood evaluation in order to prevent unnecessary surgery. This case highlights the occurrence of abdominal symptoms and complications that may accompany dengue fever. Early recognition of dengue fever mimicking acute appendicitis will avoid non-therapeutic operation and the diagnosis may be aided by blood investigations indicating a leucopenia, which is uncommon in patients with suppurative acute appendicitis. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. 4-D crustal structure of the conterminous U.S.: Continental assembly, crustal growth, and deformation history from receiver functions, xenoliths, and structural mapping

    Science.gov (United States)

    Schulte-Pelkum, V.; Mahan, K. H.

    2015-12-01

    We investigate seismic and geological features related to the tectonic evolution of the crust on a continent-wide scale. We present continent-wide features using Transportable Array data receiver function analysis, followed by regional comparisons to tie to ground truth from xenolith studies and structural mapping. We stress that the Transportable Array, at ~75 km station spacing, only offers a collection of point measurements of the crust due to the lack of crossing raypaths. 7.x layers (lower crust with high seismic velocities) can be created during crustal growth processes such as magmatic or mechanical underplating and during crustal modification such as large-scale melting. We present receiver function results and a compilation of previous regional studies using refraction data or receiver functions from regional dense networks. 7.x layers appear predominantly in parts of the northern U.S. Cordillera and across the southeastern U.S. We compare the seismic results with a xenolith study in Montana that details incremental growth of the 7.x layer from the Archean on. Hydration of a granulitic lower crust can destroy the 7.x layer and has the potential to cause epirogenic uplift. We interpret the pattern seen across the Transportable Array in the light of this hypothesis. Ductile deformation of the deep crust generates shear fabrics that can be detected seismically. Receiver functions detect shear zones via contrasts in foliation to the surrounding material. We map foliation strikes and depths in the crust across the Transportable Array using azimuthal analysis of receiver functions. Strikes from receiver functions typically align with surface fault traces in tectonically active regions, with depths of the converters exceeding the brittle zone. We discuss continent-wide strikes mapped with receiver functions. Contrasting orientations of Proterozoic shear zones and pervasive surrounding foliations in basement exposures in Colorado are reflected in seismic results

  11. Erosion of the French Alpine foreland controlled by crustal thickening

    Science.gov (United States)

    Schwartz, Stéphane; Gautheron, Cécile; Audin, Laurence; Nomade, Jérôme; Dumont, Thierry; Barbarand, Jocelyn; Pinna-Jamme, Rosella; van der Beek, Peter

    2017-04-01

    In alpine-type collision belts, deformation of the foreland may occur as a result of forward propagation of thrusting and is generally associated with thin-skinned deformation mobilizing the sedimentary cover in fold-and-thrust belts. Locally, foreland deformation can involve crustal-scale thrusting and produce large-scale exhumation of crystalline basement resulting in significant relief generation. In this study, we investigate the burial and exhumation history of Tertiary flexural basins located in the western Alpine foreland, at the front of the Digne thrust-sheet (SE France), using low-temperature apatite fission-track (AFT) and (U-Th)/He (AHe) thermochronology. Based on the occurrence of partially to totally reset apatite grain ages, we document 3.3 to 4.0 km burial of these basins remnants between 12-6 Ma, related to thin-skinned thrust-sheet emplacement without major relief generation. The onset of exhumation is dated at 6 Ma and is linked to erosion associated with subsequent relief development. This evolution does not appear controlled by major climate changes (Messinian crisis) or by European slab breakoff. Rather, we propose that the erosional history of the Digne thrust-sheet corresponds to basement involvement in foreland deformation, leading to crustal thickening and the incipient formation of a new external crystalline massif. Our study highlights the control of deep-crustal tectonic processes on foreland relief development and its erosional response at mountain fronts.

  12. Plate tectonics and crustal deformation around the Japanese Islands

    Science.gov (United States)

    Hashimoto, Manabu; Jackson, David D.

    1993-01-01

    We analyze over a century of geodetic data to study crustal deformation and plate motion around the Japanese Islands, using the block-fault model for crustal deformation developed by Matsu'ura et al. (1986). We model the area including the Japanese Islands with 19 crustal blocks and 104 faults based on the distribution of active faults and seismicity. Geodetic data are used to obtain block motions and average slip rates of faults. This geodetic model predicts that the Pacific plate moves N deg 69 +/- 2 deg W at about 80 +/- 3 mm/yr relative to the Eurasian plate which is much lower than that predicted in geologic models. Substantial aseismic slip occurs on the subduction boundaries. The block containing the Izu Peninsula may be separated from the rigid part of the Philippine Sea plate. The faults on the coast of Japan Sea and the western part of the Median Tectonic Line have slip rates exceeding 4 mm/yr, while the Fossa Magna does not play an important role in the tectonics of the central Japan. The geodetic model requires the division of northeastern Japan, contrary to the hypothesis that northeastern Japan is a part of the North American plate. Owing to rapid convergence, the seismic risk in the Nankai trough may be larger than that of the Tokai gap.

  13. Global Correlations of Mantle Structure with Crustal Tectonic Regions

    Science.gov (United States)

    Paulson, E.; Jordan, T. H.

    2011-12-01

    Tomographic models of Earth's mantle depend on a priori estimates of crustal elastic structure, but the model prior is usually independent of other structural information about the crust, such as geochronological age and tectonic history. Therefore, the correlation of mantle models with crustal structure can provide powerful insights about the relationship of mantle heterogeneity to lithospheric dynamics and continental evolution. In a meta-analysis of more than 20 whole-mantle tomographic models published by various research groups, we estimate the correlation between upper-mantle seismic structure and crustal tectonic structure by projecting the tomographic models onto the GTR1 global tectonic regionalization. The 5 x 5 degree GTR1 map comprises three continental regions based on generalized tectonic behavior during the Phanerozoic: S (Precambrian shields and platforms), P (Phanerozoic platforms), Q (Phanerozoic orogenic zones); as well as three oceanic regions based on crustal age: A (0-25 Ma), B (25-100 Ma), and C (>100 Ma). We computed shear-velocity perturbation profiles by averaging a tomographic model over each of the six tectonic regions. For each model, we assessed the statistical significance of the inter-regional variations at a fixed depth by computing the intra-regional variance and correlation length. The regionalized velocity profiles of the upper mantle are similar among all of the tomographic models that we analyzed. Within the oceanic regions, the models display a consistent increase of shear velocity with crustal age that remains statistically significant to a depth of 200 km. The oceanic shear-velocity variations are consistent with high-resolution models derived from anisotropic inversions of multi-phase waveform data in localized regions. The profiles for regions S and P show consistent and statistically significant cratonic signatures extending below 300 km depth. In particular, the shear velocity gradients of both regions are distinctly

  14. Using a Genetic Algorithm to Model Broadband Regional Waveforms for Crustal Structure in the Western United States

    Science.gov (United States)

    Bhattacharyya, Joydeep; Sheehan, Anne F.; Tiampo, Kristy; Rundle, John

    1999-01-01

    In this study, we analyze regional seismograms to obtain the crustal structure in the eastern Great Basin and western Colorado plateau. Adopting a for- ward-modeling approach, we develop a genetic algorithm (GA) based parameter search technique to constrain the one-dimensional crustal structure in these regions. The data are broadband three-component seismograms recorded at the 1994-95 IRIS PASSCAL Colorado Plateau to Great Basin experiment (CPGB) stations and supplemented by data from U.S. National Seismic Network (USNSN) stations in Utah and Nevada. We use the southwestern Wyoming mine collapse event (M(sub b) = 5.2) that occurred on 3 February 1995 as the seismic source. We model the regional seismograms using a four-layer crustal model with constant layer parameters. Timing of teleseismic receiver functions at CPGB stations are added as an additional constraint in the modeling. GA allows us to efficiently search the model space. A carefully chosen fitness function and a windowing scheme are added to the algorithm to prevent search stagnation. The technique is tested with synthetic data, both with and without random Gaussian noise added to it. Several separate model searches are carried out to estimate the variability of the model parameters. The average Colorado plateau crustal structure is characterized by a 40-km-thick crust with velocity increases at depths of about 10 and 25 km and a fast lower crust while the Great Basin has approximately 35- km-thick crust and a 2.9-km-thick sedimentary layer.

  15. Seismic and gravity modelling of crustal structure in the Central Graben, North Sea. Observations along MONA LISA profile 3

    Science.gov (United States)

    Nielsen, L.; Balling, N.; Jacobsen, B. H.; MONA LISA Working Group

    2000-12-01

    High quality wide-angle and deep normal-incidence seismic data sets recorded during the MONA LISA (Marine and Onshore North Sea Acquisition for Lithospheric Seismic Analysis) experiment have allowed detailed crustal investigations in the area of the Central Graben and south-eastern North Sea to be conducted. An integrated velocity-density model based on a joint inversion of traveltimes and gravity data is presented for the crust and uppermost mantle along MONA LISA line 3, which crosses the Central Graben approximately perpendicular to its strike direction. This model shows pronounced crustal thinning and associated Moho uplift beneath the deepest part of the Central Graben. In the graben area, Moho is interpreted to be situated at 25 km depth and the crystalline crust is about a factor of 2 thinner than in the surrounding crustal provinces, where Moho is interpreted to reach depths between 32 and 36 km. Maximum thickness of the sedimentary column in the Central Graben is 10-11 km. The mass deficit of the thick sediments is compensated by the Moho uplift. The modelled Moho coincides with the base of lower crustal reflectivity observed in the coincident normal-incidence seismic section. Good overall agreement between the integrated velocity-density model and the normal-incidence data is observed. The migrated deep seismic reflection section recorded to 26 s traveltime contains deep west-ward and east-ward dipping events symmetric about the deepest part of the Central Graben. These dipping upper mantle reflections may be linked to extensional processes that formed the Central Graben. At least one of the upper mantle dipping reflectors may be a reactivated structure formed originally during Caledonian collision.

  16. "Storms of crustal stress" and AE earthquake precursors

    Directory of Open Access Journals (Sweden)

    G. P. Gregori

    2010-02-01

    Full Text Available Acoustic emission (AE displays violent paroxysms preceding strong earthquakes, observed within some large area (several hundred kilometres wide around the epicentre. We call them "storms of crustal stress" or, briefly "crustal storms". A few case histories are discussed, all dealing with the Italian peninsula, and with the different behaviour shown by the AE records in the Cephalonia island (Greece, which is characterized by a different tectonic setting.

    AE is an effective tool for diagnosing the state of some wide slab of the Earth's crust, and for monitoring its evolution, by means of AE of different frequencies. The same effect ought to be detected being time-delayed, when referring to progressively lower frequencies. This results to be an effective check for validating the physical interpretation.

    Unlike a seismic event, which involves a much limited focal volume and therefore affects a restricted area on the Earth's surface, a "crustal storm" typically involves some large slab of lithosphere and crust. In general, it cannot be easily reckoned to any specific seismic event. An earthquake responds to strictly local rheological features of the crust, which are eventually activated, and become crucial, on the occasion of a "crustal storm". A "crustal storm" lasts typically few years, eventually involving several destructive earthquakes that hit at different times, at different sites, within that given lithospheric slab.

    Concerning the case histories that are here discussed, the lithospheric slab is identified with the Italian peninsula. During 1996–1997 a "crustal storm" was on, maybe elapsing until 2002 (we lack information for the period 1998–2001. Then, a quiet period occurred from 2002 until 26 May 2008, when a new "crustal storm" started, and by the end of 2009 it is still on. During the 1996–1997 "storm" two strong earthquakes occurred (Potenza and

  17. Crustal Seismic Structure along the East Pacific Rise 8° 20'N to 10° 10'N: Crustal melt accumulation and its relation to Mantle Melt Delivery, Tectonic Segmentation, Seafloor Geology and Hydrothermal Activity

    Science.gov (United States)

    Christopher, L. M.; Dunn, R.; Toomey, D.; Wilcock, W.; Detrick, R.

    2003-12-01

    The UNDERSHOOT seismic experiment was designed to test competing magma supply models for the East Pacific Rise (EPR). P-wave energy that traverses the ridge within the crust allows us to map the variability of magma storage within the crust along the entire length of the transform-bounded segment of the EPR between the Siqueiros and Clipperton fracture zones. This 200-km-long section of ridge exhibits several small discontinuities of the bathymetric structure and one large overlapping spreading center (OSC) at 9° 03'N. Earlier work has shown that the ridge is underlain by a shallow melt lens at approximately 1.5 km depth and by a prominent low velocity zone (4-8 km wide) that extends from the melt lens downwards into the mantle. This low velocity zone is indicative of high temperatures and a partially molten region of up to 10-40 percent magma storage. During the undershoot experiment P-wave crustal refractions and Moho reflections uniformly sampled this low-velocity zone along the entire length of this transform-bounded ridge segment. We use this data to tomographically image variations of the low-velocity zone along the ridge, including crustal thickness variations, and by inference variations in magma storage and supply. We jointly solve for the three-dimensional velocity structure of the crust and crustal thickness using a newly developed tomographic technique. While vertical resolution is poor beneath the rise, the high density of crossing ray paths, over a wide range of angles, provides excellent constraints on lateral variations in velocity structure. Initial results of this study do not reveal a discontinuity in the crustal low-velocity region beneath the OSC as expected by some models of OSC formation. This result correlates with a mantle tomographic image [Dunn et al., 2001] which likewise does not reveal a discontinuity in the mantle level low-velocity region just beneath the OSC. Our results, in combination with tomographic images of the uppermost

  18. Various Tumor-Mimicking Lesions in the Musculoskeletal System: Causes and Diagnostic Approach

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sue Yon; Park, Ji Seon; Ryu, Kyung Nam; Jin, Wook [Kyung Hee University Medical Center, Seoul (Korea, Republic of); Park, So Young [East-West Neo Medical Center, Kyung Hee University, Seoul (Korea, Republic of)

    2011-04-15

    Tumor-mimicking lesions in the musculoskeletal system can be defined as lesions mistaken as tumors due to the presence of palpation upon physical examination or a tumor-like appearance upon radiological examination. Moreover, tumor mimicking lesions show diverse etiologies and anatomic locations. We illustrated the various tumor-mimicking lesions involving bone and soft tissue. In this review, the tumor-mimicking lesions were classified into those based on clinical examination and those based on radiological examination in musculoskeletal radiology. Awareness of the various causes of tumor-mimicking lesions, correctly obtaining clinical information, and the proper selection of imaging modality are important for the differentiation of tumor-mimicking lesions from true neoplasms

  19. Crustal and lithospheric imaging of the Atlas Mountains of Morocco inferred from magnetotelluric data

    Science.gov (United States)

    Kiyan, D.; Jones, A. G.; Fullea, J.; Hogg, C.; Ledo, J.; Sinischalchi, A.; Campanya, J.; Picasso Phase II Team

    2010-12-01

    The Atlas System of Morocco is an intra-continental mountain belt extending for more than 2,000 km along the NW African plate with a predominant NE-SW trend. The System comprises three main branches: the High Atlas, the Middle Atlas, and the Anti Atlas. We present the results of a very recent multi-institutional magnetotelluric (MT) experiment across the Atlas Mountains region that started in September, 2009 and ended in February, 2010, comprising acquisition of broadband and long-period MT data. The experiment consisted of two profiles: (1) a N-S oriented profile crossing the Middle Atlas through the Central High Atlas to the east and (2) a NE-SW profile crossing the western High Atlas towards the Anti Atlas to the west. The MT measurements are part of the PICASSO (Program to Investigate Convective Alboran Sea System Overturn) and the concomitant TopoMed (Plate re-organization in the western Mediterranean: Lithospheric causes and topographic consequences - an ESF EUROCORES TOPO-EUROPE project) projects, to develop a better understanding of the internal structure and evolution of the crust and lithosphere of the Atlas Mountains. The MT data have been processed with robust remote reference methods and submitted to comprehensive strike and dimensionality analysis. Two clearly depth-differentiated strike directions are apparent for crustal (5-35 km) and lithospheric (50-150 km) depth ranges. These two orientations are roughly consistent with the NW-SE Africa-Eurasia convergence acting since the late Cretaceous, and the NNE-SSW Middle Atlas, where Miocene to recent Alkaline volcanism is present. Two-dimensional (2-D) smooth electrical resistivity models were computed independently for both 50 degrees and 20 degrees E of N strike directions. At the crustal scale, our preliminary results reveal a middle to lower-crustal conductive layer stretching from the Middle Atlas southward towards the High Moulouya basin. The most resistive (and therefore potentially thickest

  20. Density heterogeneity of the North American upper mantle from satellite gravity and a regional crustal model

    DEFF Research Database (Denmark)

    Herceg, Matija; Artemieva, Irina; Thybo, Hans

    2014-01-01

    We present a regional model for the density structure of the North American upper mantle. The residual mantle gravity anomalies are based on gravity data derived from the GOCE geopotential models with crustal correction to the gravity field being calculated from a regional crustal model. We analyze...... how uncertainties and errors in the crustal model propagate from crustal densities to mantle residual gravity anomalies and the density model of the upper mantle. Uncertainties in the residual upper (lithospheric) mantle gravity anomalies result from several sources: (i) uncertainties in the velocity......-density conversion and (ii) uncertainties in knowledge of the crustal structure (thickness and average Vp velocities of individual crustal layers, including the sedimentary cover). In this study, we address both sources of possible uncertainties by applying different conversions from velocity to density...

  1. {sup 18}F-FDG-avid sites mimicking active disease in pediatric Hodgkin's

    Energy Technology Data Exchange (ETDEWEB)

    Kaste, Sue C. [St. Jude Children' s Research Hospital, Departments of Radiological Sciences and Hematology-Oncology, Memphis, TN (United States); Howard, Scott C.; Hudson, Melissa M. [St. Jude Children' s Research Hospital, Hematology-Oncology Department, Memphis, TN (United States); McCarville, Elizabeth B.; Krasin, Matthew J. [St. Jude Children' s Research Hospital, Radiological Sciences, Memphis, TN (United States); Kogos, Philip G. [University of Tennessee College of Medicine, St. Jude Children' s Research Hospital, Radiological Sciences, Department of Radiology, Memphis, TN (United States)

    2005-02-01

    About 1,700 children in the United States are diagnosed yearly with lymphomas; Hodgkin's disease accounts for approximately half of these cases, or 6% of all childhood cancers. Contemporary therapy allows for the achievement of remission in the majority of cases. The fusion of positron emission tomography (PET) with CT provides the most accurate imaging method for disease characterization and treatment response. However, experience with {sup 18}F-FDG PET-CT is limited in pediatric Hodgkin's disease. Numerous non-oncologic processes can mimic recurrent or residual tumor. This pictorial addresses mimickers of disease such as uptake in normal structures, infections, transforming germinal canters and effects of therapy on normal tissues. It is essential for radiologists to be familiar with these findings in order to stage disease activity and therapeutic response accurately. (orig.)

  2. Seismic refraction investigations on the crustal structure of the western Jameson Land Basin, East Greenland

    Science.gov (United States)

    Fechner, Notker; Jokat, Wilfried

    1996-07-01

    In 1990, a combined land-sea experiment in the Hall Bredning, Scoresby Sund (East Greenland) revealed new information about the crustal structure of the Jameson Land Basin. The sediments and the upper and lower crust have been imaged by a 710-km-long network of seismic refraction lines. Our data indicate that the crust-mantle boundary is at a depth of 24 km close to the western coast of Jameson Land and deepens to 31 km toward the western termination of Hall Bredning. The sediments thin from 8-km thickness in the east to almost 0 km close to Milne Land. Our cross sections indicate that Jameson Land is an asymmetrical, half-graben shaped sedimentary basin with a N-S striking axis.

  3. Characterization of transverse isotropy in compressed tissue-mimicking phantoms.

    Science.gov (United States)

    Urban, Matthew W; Lopera, Manuela; Aristizabal, Sara; Amador, Carolina; Nenadic, Ivan; Kinnick, Randall R; Weston, Alexander D; Qiang, Bo; Zhang, Xiaoming; Greenleaf, James F

    2015-06-01

    Tissues such as skeletal muscle and kidneys have well-defined structure that affects the measurements of mechanical properties. As an approach to characterize the material properties of these tissues, different groups have assumed that they are transversely isotropic (TI) and measure the shear wave velocity as it varies with angle with respect to the structural architecture of the organ. To refine measurements in these organs, it is desirable to have tissue-mimicking phantoms that exhibit similar anisotropic characteristics. Some approaches involve embedding fibers into a material matrix. However, if a homogeneous solid is under compression due to a static stress, an acoustoelastic effect can manifest that makes the measured wave velocities change with the compression stress. We propose to exploit this characteristic to demonstrate that stressed tissue mimicking phantoms can be characterized as a TI material. We tested six phantoms made with different concentrations of gelatin and agar. Stress was applied by the weight of a water container centered on top of a plate on top of the phantom. A linear array transducer and a V-1 Verasonics system were used to induce and measure shear waves in the phantoms. The shear wave motion was measured using a compound plane wave imaging technique. Autocorrelation was applied to the received in-phase/quadrature data. The shear wave velocity, c, was estimated using a Radon transform method. The transducer was mounted on a rotating stage so measurements were made every 10° over a range of 0° to 360°, where the stress is applied along 0° to 180° direction. The shear moduli were estimated. A TI model was fit to the data and the fractional anisotropy was evaluated. This approach can be used to explore many configurations of transverse isotropy with the same phantom, simply by applying stress to the tissue-mimicking phantom.

  4. Characterization of Transverse Isotropy in Compressed Tissue Mimicking Phantoms

    Science.gov (United States)

    Urban, Matthew W.; Lopera, Manuela; Aristizabal, Sara; Amador, Carolina; Nenadic, Ivan; Kinnick, Randall R.; Weston, Alexander D.; Qiang, Bo; Zhang, Xiaoming; Greenleaf, James F.

    2015-01-01

    Tissues such as skeletal muscle and kidneys have well-defined structure that affects the measurements of mechanical properties. As an approach to characterize the material properties of these tissues, different groups have assumed that they are transversely isotropic (TI) and measure the shear wave velocity as it varies with angle with respect to the structural architecture of the organ. To refine measurements in these organs, it is desirable to have tissue mimicking phantoms that exhibit similar anisotropic characteristics. Some approaches involve embedding fibers into a material matrix. However, if a homogeneous solid is under compression due to a static stress, an acoustoelastic effect can manifest which makes the measured wave velocities change with the compression stress. We propose to exploit this characteristic to demonstrate that stressed tissue mimicking phantoms can be characterized as a TI material. We tested six phantoms made with different concentrations of gelatin and agar. Stress was applied by the weight of a water container centered on top of a plate on top of the phantom. A linear array transducer and a V-1 Verasonics system were used to induce and measure shear waves in the phantoms. The shear wave motion was measured using a compound plane wave imaging technique. Autocorrelation was applied to the received in-phase/quadrature data. The shear wave velocity, c, was estimated using a Radon transform method. The transducer was mounted on a rotating stage so measurements were made every 10° over a range of 0–360°, where the stress is applied along 0–180° direction. The shear moduli were estimated. A TI model was fit to the data and the fractional anisotropy was evaluated. This approach can be used to explore many configurations of transverse isotropy with the same phantom, simply by applying stress to the tissue mimicking phantom. PMID:26067038

  5. Evaluation of tomosynthesis elastography in a breast-mimicking phantom

    Energy Technology Data Exchange (ETDEWEB)

    Engelken, Florian Jan, E-mail: florian.engelken@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Sack, Ingolf, E-mail: ingolf.sack@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Klatt, Dieter, E-mail: dieter.klatt@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Fischer, Thomas, E-mail: thom.fischer@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Fallenberg, Eva Maria, E-mail: eva.fallenberg@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Bick, Ulrich, E-mail: ulrich.bick@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany); Diekmann, Felix, E-mail: felix.diekmann@charite.de [Department of Radiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin (Germany)

    2012-09-15

    Objective: To evaluate whether measurement of strain under static compression in tomosynthesis of a breast-mimicking phantom can be used to distinguish tumor-simulating lesions of different elasticities and to compare the results to values predicted by rheometric analysis as well as results of ultrasound elastography. Materials and methods: We prepared three soft breast-mimicking phantoms containing simulated tumors of different elasticities. The phantoms were imaged using a wide angle tomosynthesis system with increasing compression settings ranging from 0 N to 105 N in steps of 15 N. Strain of the inclusions was measured in two planes using a commercially available mammography workstation. The elasticity of the phantom matrix and inclusion material was determined by rheometric analysis. Ultrasound elastography of the inclusions was performed using two different ultrasound elastography algorithms. Results: Strain at maximal compression was 24.4%/24.5% in plane 1/plane 2, respectively, for the soft inclusion, 19.6%/16.9% for the intermediate inclusion, and 6.0%/10.2% for the firm inclusion. The strain ratios predicted by rheometrical testing were 0.41, 0.83 and 1.26 for the soft, intermediate, and firm inclusions, respectively. The strain ratios obtained for the soft, intermediate, and firm inclusions were 0.72 ± 0.13, 1.02 ± 0.21 and 2.67 ± 1.70, respectively for tomosynthesis elastography, 0.91, 1.64 and 2.07, respectively, for ultrasound tissue strain imaging, and 0.97, 2.06 and 2.37, respectively, for ultrasound real-time elastography. Conclusions: Differentiation of tumor-simulating inclusions by elasticity in a breast mimicking phantom may be possible by measuring strain in tomosynthesis. This method may be useful for assessing elasticity of breast lesions tomosynthesis of the breast.

  6. Crustal motion in Indonesia from Global Positioning System measurements

    Science.gov (United States)

    Bock, Y.; Prawirodirdjo, L.; Genrich, J. F.; Stevens, C. W.; McCaffrey, R.; Subarya, C.; Puntodewo, S. S. O.; Calais, E.

    2003-08-01

    We present the crustal motion velocity field for the Indonesian archipelago based on Global Positioning System (GPS) field surveys conducted from 1991 to 1997, and 2001, totaling more than 150 sites, as well as on a reanalysis of global tracking data in the Scripps Orbit and Permanent Array Center archive from 1991 to 2001 in International Terrestrial Reference Frame 2000. We compute poles of rotation for the Australia, Eurasia, and Pacific plates based on our analysis of the global GPS data. We find that regional tectonics is dominated by the interaction of four discrete, rotating blocks spanning significant areas of the Sunda Shelf, the South Banda arc, the Bird's Head region of New Guinea, and East Sulawesi. The largest, the Sunda Shelf block (SSH), is estimated to be moving 6 ± 3 mm/yr SE relative to Eurasia. The South Banda block (SBB) rotates clockwise relative to both the SSH and Australia plate, resulting in 15 ± 8 mm/yr of motion across the Timor trough and 60 ± 3 mm/yr of shortening across the Flores Sea. Southern New Guinea forms part of the Australia plate from which the Bird's Head block (BHB) moves rapidly WSW, subducting beneath the Seram trough. The East Sulawesi block rotates clockwise about a nearby axis with respect to the Sunda Shelf, thereby transferring east-west shortening between the Pacific and Eurasia plates into north-south shortening across the North Sulawesi trench. Except for the Sunda Shelf, the crustal blocks are all experiencing significant internal deformation. In this respect, crustal motion in those regions does not fit the microplate tectonics model.

  7. Effect of Crustal Density Structures on GOCE Gravity Gradient Observables

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    Robert Tenzer Pavel Novák

    2013-01-01

    Full Text Available We investigate the gravity gradient components corrected for major known anomalous density structures within the Earth¡¦s crust. Heterogeneous mantle density structures are disregarded. The gravimetric forward modeling technique is utilized to compute the gravity gradients based on methods for a spherical harmonic analysis and synthesis of a gravity field. The Earth¡¦s gravity gradient components are generated using the global geopotential model GOCO-03s. The topographic and stripping gravity corrections due to the density contrasts of the ocean and ice are computed from the global topographic/bathymetric model DTM2006.0 (which also includes the ice-thickness dataset. The discrete data of sediments and crust layers taken from the CRUST2.0 global crustal model are then used to apply the additional stripping corrections for sediments and remaining anomalous crustal density structures. All computations are realized globally on a one arc-deg geographical grid at a mean satellite elevation of 255 km. The global map of the consolidated crust-stripped gravity gradients reveals distinctive features which are attributed to global tectonics, lithospheric plate configuration, lithosphere structure and mantle dynamics (e.g., glacial isostatic adjustment, mantle convection. The Moho signature, which is the most pronounced signal in these refined gravity gradients, is superimposed over a weaker gravity signal of the lithospheric mantle. An interpretational quality of the computed (refined gravity gradient components is mainly limited by a low accuracy and resolution of the CRUST2.0 sediment and crustal layer data and unmodeled mantle structures.

  8. MOLA Topography of the Crustal Dichotomy Boundary Zone, Mars

    Science.gov (United States)

    Frey, Herbert V.; E. H., Susan; H., James

    1998-01-01

    Mars Orbiter Laser Altimeter (MOLA) profiles frequently cross the crustal dichotomy boundary where the transition zone (TZ) between cratered highland terrain (CT) and lowland smooth plains (SP) is marked by mesas and knobby terrain. The detailed topographic character of the boundary zone is longitudinally variable, as is the geomorphology of the TZ. Some portions of the boundary are associated with an outer ring of the Utopia impact basin; MOLA topography is consistent with this. The regional character of the boundary topography is a 2-4 km step function from nearly flat SP to almost as flat CT. This rise has a regional slope of 1-2 degrees, 50-100 times that of the Cr and SP away from TZ, which suggests a significant change in crustal properties (thickness, composition or both) across the TZ. The overall topography is very similar to that at some passive continent-oceanic crustal margins on the Earth, with the seafloor allowed to adjust upward after removal of the overlying water. A possible temporal constraint on the CT/SP elevation difference comes from two MOLA profiles which pass through two large (150 km diameter) craters located at the boundary in Aeolis. The N and S rims of the more degraded crater are at the same elevation; north of the N rim the topography drops by greater than 2 km to the floor of the TZ. This crater predates the elevation offset between CT and TZ floor. The better preserved crater (Gale) has a N rim 2 km lower than its S rim, and appears to have been emplaced on a pre-existing regional slope of about I degree. Gale probably post- dates the elevation difference between CT and TZ floor. Based on the stratigraphy of the units in which these craters are found, the elevation difference appears to have been in place in the Mid to Late Noachian.

  9. Crustal structure beneath Portugal from teleseismic Rayleigh Wave Ellipticity

    Science.gov (United States)

    Attanayake, Januka; Ferreira, Ana M. G.; Berbellini, Andrea; Morelli, Andrea

    2017-08-01

    Up until now, Portugal lacked a countrywide shear velocity model sampling short length-scale crustal structure, which limits interpretations of seismicity and tectonics, and predictions of strong ground motion. In turn, such interpretations and predictions are important to help mitigate risk of destruction from future large on- and offshore earthquakes similar to those that Portugal has experienced in the past (e.g. the Mw 8.5-8.7 tsunamigenic event in 1755). In this study, we measured teleseismic Rayleigh Wave Ellipticity (RWE) from 33 permanent and temporary seismic stations in Portugal with wave periods between 15 s and 60 s, and inverted it for 1-D models of shear wave velocity (Vs) structure beneath each station using a fully non-linear Monte Carlo method. Because RWE is strongly sensitive to the uppermost few kilometres of the crust, both RWE measurements and Vs models are spatially correlated with surface geology in Portugal. For instance, we find that sedimentary basins produced by rifting that had begun in the Mesozoic such as the Lusitanian Basin (LB) and the Lower Tagus-Sado Basin (LTSB) are characterised by higher RWE (lower Vs). Interestingly, we observe similar RWE (and Vs) values in the interior of the Central Iberian Zone (CIZ), which is a metamorphic belt of Paleozoic age. Together with reduced crustal thickness previously estimated for the same parts of the CIZ, this suggests that the CIZ might have experienced an episode of extension possibly simultaneous to Mesozoic rifting. The Galicia-Tras-os-Montes-Zone (GTMZ) that has undergone polyphased deformation since the Paleozoic is characterised by the lowest RWE (highest Vs) in Portugal. Ossa Morena Zone and the South Portuguese Zone exhibit intermediate Vs values when compared to that of basins and the GTMZ. Our crustal Vs model can be used to provide new insights into the tectonics, seismicity and strong ground motion in Portugal.

  10. Endometriosis mimicking the perianal fistula tract: Case report

    Directory of Open Access Journals (Sweden)

    Gül Türkcü

    2014-09-01

    Full Text Available Endometriosis is the presence of endometrial glands and stroma outside the uterine cavity. Nowadays, in many cases, although routine use of episiotomy perineal endo metriosis is extremely rare. A 36 year old female patient was referred to our hospital with complaints of pain in the perianal region for five months. On physical examination, stiffness was palpated and then magnetic resonance im aging (MRI was performed. MRI is compatible with fistula tract. The lesion was excised and the histopathological appearance correspond to endometriosis. Perianal endo metriosis is rare in the perianal region and in the clinic mimicking perianal fistulas and malignancy should be kept in mind in the differential diagnosis

  11. Mental foramen mimicking as periapical pathology - A case report

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    Anusha Rangare Lakshman

    2014-09-01

    Full Text Available The radiographic recognition of any disease requires a thorough knowledge of the radiographic appearance of normal structure. Intelligent diagnosis mandates an appreciation of the wide range of variation in the appearance of normal anatomical structures. The mental foramen is usually the anterior limit of the inferior dental canal that is apparent on radiographs. It opens on the facial aspect of the mandible in the region of the premolars. It can pose diagnostic dilemma radiographically because of its anatomical variation which can mimic as a periapical pathosis. Hereby we are reporting a rare case of superimposed mental foramen over the apex of right mandibular second premolar mimicking as periapical pathology.

  12. Splenosis with lower gastrointestinal bleeding mimicking colonical gastrointestinal stromal tumour.

    Science.gov (United States)

    Xiao, Shuo-Meng; Xu, Rui; Tang, Xiao-Li; Ding, Zhi; Li, Ji-Man; Zhou, Xiang

    2017-04-11

    Splenosis refers to the heterotopic transplantation of splenic tissue following splenic trauma or splenectomy. Splenosis is typically asymptomatic and is often identified incidentally. We report a case of splenosis with colon and stomach invasion presenting as lower gastrointestinal bleeding and mimicking colonic gastrointestinal stromal tumour (GIST). The importance of suspicion for splenosis in patients with a history of splenic injury should be highlighted. Computed tomography (CT)-guided biopsy, nuclear scintigraphy and ferumoxide-enhanced magnetic resonance imaging (MRI) can support an accurate diagnosis. An accurate diagnosis of splenosis is important to avoid unnecessary operations, especially in patients with previous histories of splenic trauma or splenectomy.

  13. Abdominal Splenosis Mimicking Hepatic Tumor: A Case Report

    Directory of Open Access Journals (Sweden)

    Ming-Lun Yeh

    2008-11-01

    Full Text Available Diagnosis of abdominal splenosis is often undiagnosed until treatment for splenic rupture or splenectomy. This report describes a patient with splenosis mimicking hepatic tumor. The patient had a history of splenic trauma with splenectomy and chronic hepatitis C. After routine abdominal ultrasound revealed a liver nodule, further imaging studies, including magnetic resonance imaging, computed tomography and angiography, were performed. After the patient eventually underwent surgery, pathology revealed splenic tissue. Despite its distinguishable clinical features, splenosis is difficult to identify by modern imaging modalities. Therefore, accurate and timely diagnosis of this disease requires constant vigilance.

  14. Abdominal splenosis mimicking hepatic tumor: a case report.

    Science.gov (United States)

    Yeh, Ming-Lun; Wang, Liang-Yen; Huang, Ching-I; Hsieh, Ming-Yen; Lin, Zu-Yau; Chuang, Wan-Long; Chang, Wen-Tsan; Wu, Chun-Chieh; Chen, Chiao-Yun

    2008-11-01

    Diagnosis of abdominal splenosis is often undiagnosed until treatment for splenic rupture or splenectomy. This report describes a patient with splenosis mimicking hepatic tumor. The patient had a history of splenic trauma with splenectomy and chronic hepatitis C. After routine abdominal ultrasound revealed a liver nodule, further imaging studies, including magnetic resonance imaging, computed tomography and angiography, were performed. After the patient eventually underwent surgery, pathology revealed splenic tissue. Despite its distinguishable clinical features, splenosis is difficult to identify by modern imaging modalities. Therefore, accurate and timely diagnosis of this disease requires constant vigilance.

  15. Aneurysm of the common iliac vein mimicking a pelvic mass

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Eun Joo; Kim, Dong Hun [Dept. of Radiology, Chosun University College of Medicine, Gwangju (Korea, Republic of); Suk, Eun Ha [Dept. of Anesthesiology and Pain Medicine, Seonam University College of Medicine, Namwon (Korea, Republic of)

    2013-07-15

    Venous aneurysm, especially of primary origin, is rare. The authors report a case of a 63-year-old female who was admitted for back pain and an aneurysm of the common iliac which was detected incidentally. CT, magnetic resonance (MR), Doppler ultrasonography, and conventional venography showed an aneurysm of the left common iliac vein measuring 4.5 , 00D7, 3, 00D7, 4 cm. Because there were no complications of the aneurysm, no further treatment was administered. Herein, we describe findings of a venous aneurysm of the common iliac vein mimicking a pelvic mass on CT and MR scans and with a review of the literature.

  16. Report of ischemic stroke mimicking isolated ulnar nerve paralysis

    Directory of Open Access Journals (Sweden)

    Çetin Kürşad Akpınar

    2016-12-01

    Full Text Available The cortical motor hand area is the precentral gyrus. Small cortical infarcts of this area can caused isolated hand weakness. Weakness can consist of either all fingers or ulnar-sided fingers. A 71-year-old man admitted to the emergency department with sudden weakness of the right fourth and fifth fingers Diffusion-weighted brain imaging of a magnetic resonance imaging scan revealed acute infarction of right precentral gyrus. Cardioembolus is the determined ischemic stroke subtype. This report presented a case of ischemic stroke mimicking isolated ulnar nerve paralysis.

  17. Simple bone cyst of mandible mimicking periapical cyst.

    Science.gov (United States)

    Hs, Charan Babu; Rai, Bhagawan Das; Nair, Manju A; Astekar, Madhusudan S

    2012-05-29

    Simple bone cysts (SBC) are pseudocysts occurring less commonly in the maxillofacial region. The uncertain and unclear etiopathogenesis led to numerous synonyms to refer this particular cyst. These cysts are devoid of an epithelial lining and are usually empty or contain blood or straw-colored fluid. In jaws initially it mimics a periapical cyst and later can lead to cortical bone expansion warranting for radical approach, which is seldom required. SBC is predominantly diagnosed in first two decades of life. Here we report a case of solitary bone cyst mimicking a periapical cyst of a mandibular molar in a 37-year-old patient.

  18. Simple bone cyst of mandible mimicking periapical cyst

    Directory of Open Access Journals (Sweden)

    Charan Babu HS

    2012-05-01

    Full Text Available Simple bone cysts (SBC are pseudocysts occurring less commonly in the maxillofacial region. The uncertain and unclear etiopathogenesis led to numerous synonyms to refer this particular cyst. These cysts are devoid of an epithelial lining and are usually empty or contain blood or straw-colored fluid. In jaws initially it mimics a periapical cyst and later can lead to cortical bone expansion warranting for radical approach, which is seldom required. SBC is predominantly diagnosed in first two decades of life. Here we report a case of solitary bone cyst mimicking a periapical cyst of a mandibular molar in a 37-year-old patient.

  19. Tinea capitis caused by Trichophyton rubrum mimicking favus.

    Science.gov (United States)

    Boyd, Alan S

    2016-12-01

    Favus is an uncommon form of tinea capitis (TC) currently seen in geographic areas with poor sanitation and limited access to health care such as emerging nations. Several variants of this condition have been described including one exhibiting a plaque composed of parchmentlike material. The makeup of this plaque has not been described. Tinea capitis is rare in adults, particularly when the infectious agent is Trichophyton rubrum, and affected patients often exhibit comorbidities associated with diminished immune surveillance. This case report describes an elderly woman with TC due to T rubrum mimicking a rare form of favus.

  20. Nephrogenic rests mimicking Wilms' tumor on CT

    Energy Technology Data Exchange (ETDEWEB)

    Subhas, Naveen; Siegelman, Stanley S. [Russell H. Morgan Department of Radiology, The Johns Hopkins Hospital and School of Medicine, 600 N. Wolfe St., 21287, Baltimore, MD (United States); Argani, Pedram [Department of Pathology, Johns Hopkins Hospital and School of Medicine, 21287, Baltimore, MD (United States); Gearhart, John P. [Department of Pediatric Urology, Brady Urologic Institute, The Johns Hopkins Hospital and School of Medicine, 21287, Baltimore, MD (United States)

    2004-02-01

    Nephrogenic rests (NR) are persistent benign remnants of embryonic renal tissue. A small percentage of these may develop into Wilms' tumor (WT). Radiologic imaging is relied upon to differentiate between these entities, with the hallmark of malignant transformation being growth on serial imaging studies. There is, however, considerable overlap in their imaging characteristics. The authors present a case of two biopsy-proven NR in a 2-year-old girl with sporadic aniridia that were indistinguishable from WT on initial radiologic studies. One of the NR grew on serial imaging studies mimicking a WT, but after resection was confirmed to be a benign hyperplastic NR on pathologic examination. (orig.)

  1. Hızma Induced Papul of Nose Mimicking Pyogenic Granuloma

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    Mualla Polat

    2014-09-01

    Full Text Available The application of body piercing is popular among young people, who consider it as a sign of marginality, beauty, or group identity. Piercing procedure is observed to cause a large number of complications such as infections, pain, inflammatory reactions, bleeding, dental fractures or fissures, and gingival damage, etc., mostly in young individuals. Hizma is a traditional body ornament worn by Anatolian women via a piercing procedure. Herein, we describe a papule of nose mimicking pyogenic granuloma as an uncommon complication of Hızma.

  2. Lepra reaction with lucio phenomenon mimicking cutaneous vasculitis.

    Science.gov (United States)

    Misra, Durga Prasanna; Parida, Jyoti Ranjan; Chowdhury, Abhra Chandra; Pani, Krushna Chandra; Kumari, Niraj; Krishnani, Narendra; Agarwal, Vikas

    2014-01-01

    Leprosy is a disease typically found in the tropics. Patients with leprosy can have varying presentation with constitutional symptoms, joint pains, skin nodules, and rarely a vasculitis-like picture with skin ulcers and neuropathy. We present a young lady who presented with the rare manifestation of skin infarcts mimicking cutaneous vasculitis, diagnosed on histopathology to have Lucio phenomenon on a background of lepromatous leprosy. With increasing migration and widespread use of biologic response modifiers, clinicians all over the world need to be aware of various presentations of leprosy as well as needing to keep an open mind while considering the differential diagnoses of vasculitis.

  3. Dual anaplastic large cell lymphoma mimicking meningioma: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Keun Ho; Kim, Ki Hwan; Lee, Ghi Jai; Lee, Hye Kyung; Shim, Jae Chan; Lee, Kyoung Eun; Suh, Jung Ho [Seoul Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of); Lee, Chae Heuck [Dept. of Neurosurgery, Ilsan Paik Hospital, Inje University College of Medicine, Goyang (Korea, Republic of)

    2014-01-01

    Anaplastic large cell lymphoma (ALCL) is a rare T cell lymphoma composed of CD30-positive lymphoid cells. Most ALCLs present as nodal disease, with skin, bone, soft tissue, lung, and liver as common extranodal sites. ALCL rarely occurs in the central nervous system and is even more infrequent in the dura of the brain. We report a case of dural-based ALCL secondary to systemic disease in a 17-year-old male that mimicked meningioma on magnetic resonance imaging and angiography.

  4. Embolized prostatic brachytherapy seeds mimicking acute chest pain syndromes

    Directory of Open Access Journals (Sweden)

    Nirmal Guragai

    2017-01-01

    Full Text Available A 59-year-old male with a history of nonobstructive coronary artery disease, diabetes mellitus, hypertension, and prostate cancer presented to the hospital with 1-day history of pleuritic chest pain. Initial workup for acute coronary event was unremarkable. Chest X-ray revealed multiple small radial densities which were linear and hyperdense, consistent with embolization of metallic seeds to the pulmonary circulation. The patient was noted to have had radioactive metallic seeds implanted for prostate cancer 6 months ago. Diagnosis of pulmonary embolization of prostatic seeds is challenging as they frequently present with chest pain mimicking acute coronary syndromes.

  5. Intracortical bone metastasis mimicking intracortical osteoid osteoma: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Yu Ri; Kim, Jee Young [St. Vincent' s Hospital, The Catholic University of Korea, Suwon (Korea, Republic of)

    2007-08-15

    Cortical metastasis usually occurs in the diaphysis of the long bones with the appearance of a cookie-bite pattern; this is associated with cortical destruction extending into the soft tissue as well as into the medullary cavity, or there can be a periosteal reaction. We report here on a 66-year-old woman who was diagnosed with intracortical metastasis in the proximal metaphysis of the right femur as an initial metastatic focus from primary lung cancer. CT detected an intracortical osteolytic lesion without cortical destruction or thickening. The MR images showed extensive peritumoral edema in the surrounding soft tissue and adjacent bone marrow edema, and this all mimicked osteoid osteoma.

  6. Lepra Reaction with Lucio Phenomenon Mimicking Cutaneous Vasculitis

    Directory of Open Access Journals (Sweden)

    Durga Prasanna Misra

    2014-01-01

    Full Text Available Leprosy is a disease typically found in the tropics. Patients with leprosy can have varying presentation with constitutional symptoms, joint pains, skin nodules, and rarely a vasculitis-like picture with skin ulcers and neuropathy. We present a young lady who presented with the rare manifestation of skin infarcts mimicking cutaneous vasculitis, diagnosed on histopathology to have Lucio phenomenon on a background of lepromatous leprosy. With increasing migration and widespread use of biologic response modifiers, clinicians all over the world need to be aware of various presentations of leprosy as well as needing to keep an open mind while considering the differential diagnoses of vasculitis.

  7. Quantifying precambrian crustal extraction: The root is the answer

    Science.gov (United States)

    Abbott, D.; Sparks, D.; Herzberg, C.; Mooney, W.; Nikishin, A.; Zhang, Y.-S.

    2000-01-01

    We use two different methods to estimate the total amount of continental crust that was extracted by the end of the Archean and the Proterozoic. The first method uses the sum of the seismic thickness of the crust, the eroded thickness of the crust, and the trapped melt within the lithospheric root to estimate the total crustal volume. This summation method yields an average equivalent thickness of Archean crust of 49 ?? 6 km and an average equivalent thickness of Proterozoic crust of 48 ?? 9 km. Between 7 and 9% of this crust never reached the surface, but remained within the continental root as congealed, iron-rich komatiitic melt. The second method uses experimental models of melting, mantle xenolith compositions, and corrected lithospheric thickness to estimate the amount of crust extracted through time. This melt column method reveals that the average equivalent thickness of Archean crust was 65 ?? 6 km. and the average equivalent thickness of Early Proterozoic crust was 60 ?? 7 km. It is likely that some of this crust remained trapped within the lithospheric root. The discrepancy between the two estimates is attributed to uncertainties in estimates of the amount of trapped, congealed melt, overall crustal erosion, and crustal recycling. Overall, we find that between 29 and 45% of continental crust was extracted by the end of the Archean, most likely by 2.7 Ga. Between 51 and 79% of continental crust was extracted by the end of the Early Proterozoic, most likely by 1.8-2.0 Ga. Our results are most consistent with geochemical models that call upon moderate amounts of recycling of early extracted continental crust coupled with continuing crustal growth (e.g. McLennan, S.M., Taylor, S.R., 1982. Geochemical constraints on the growth of the continental crust. Journal of Geology, 90, 347-361; Veizer, J., Jansen, S.L., 1985. Basement and sedimentary recycling - 2: time dimension to global tectonics. Journal of Geology 93(6), 625-643). Trapped, congealed, iron

  8. New Crustal Stress Map of the Mediterranean and Central Europe

    OpenAIRE

    Heidbach, Oliver; Custodio, Susana; Kingdon, Andrew; Mariucci, Maria Teresa; Montone, Paola; Müller, Birgit; Pierdominicini, Simona; RAJABI, Mojtaba; Reinecker, John; Reiter, Karsten; Tingay, Mark; Williams, John; Ziegler, Moritz

    2016-01-01

    The World Stress Map (WSM) Project was initiated in 1986 under the auspices of the International Lithosphere Program in order to compile globally the information on the contemporary crustal stress state. For the 30th anniversary the WSM database has been updated and increased the number of data records from 21,750 to 42,410 worldwide. For the Mediterranean and Central European stress map the number of data records has increased from 3877 to 8192. The data come from a wide range of stress indi...

  9. Crustal structure variations along the Lesser Antilles Arc

    Science.gov (United States)

    Schlaphorst, D.; Kendall, J. M.; Melekhova, E.; Blundy, J.; Baptie, B.; Latchman, J. L.

    2013-12-01

    Continental crust is predominantly formed along subduction zones. Therefore, an investigation of the crustal and mantle structure variation of these areas is crucial for understanding the growth of continental crust. This work deals with the seismological characteristics along the Lesser Antilles Arc, an island arc system built by the relatively slow subduction (~2cm/yr) of the North and South American plates beneath the Caribbean plate. The amount of subducted sediments changes significantly from sediment-rich subduction in the South to sediment-poor subduction in the North. The abundance of broadband seismic stations on the Lesser Antilles islands enables a range of seismic methods to be used to study arc processes. Furthermore, the abundance of cumulate samples allows for a detailed petrological analysis, which can be related to the seismological patterns. We use data from three component broadband stations located on the individual islands along the arc. From the island of Grenada in the South to the Virgin Islands in the North significant variations in sediment load, petrology and volcanism are observed along the arc. In this work, we investigate crustal structure using receiver functions to determine Moho depth and Vp/Vs ratio. The ratio gives an idea about the material of the subsurface as well as its water and its melt contents. The receiver functions are computed using the extended-time multitaper frequency domain cross-correlation receiver-function (ETMTRF) by Helffrich (2006). This method has the advantage of resistance to noise, which is helpful since most of the data around the arc will have been collected by stations close to the ocean, thus containing a large amount of noise. Our results show clear variations in these measurements. There are also regions where the Moho is not very sharp due to a low velocity contrast. The real data results were then compared to synthetic receiver functions from subsurface models. We compute a range of synthetic

  10. Multilayered tissue mimicking skin and vessel phantoms with tunable mechanical, optical, and acoustic properties

    Science.gov (United States)

    Chen, Alvin I.; Balter, Max L.; Chen, Melanie I.; Gross, Daniel; Alam, Sheikh K.; Maguire, Timothy J.; Yarmush, Martin L.

    2016-01-01

    Purpose: This paper describes the design, fabrication, and characterization of multilayered tissue mimicking skin and vessel phantoms with tunable mechanical, optical, and acoustic properties. The phantoms comprise epidermis, dermis, and hypodermis skin layers, blood vessels, and blood mimicking fluid. Each tissue component may be individually tailored to a range of physiological and demographic conditions. Methods: The skin layers were constructed from varying concentrations of gelatin and agar. Synthetic melanin, India ink, absorbing dyes, and Intralipid were added to provide optical absorption and scattering in the skin layers. Bovine serum albumin was used to increase acoustic attenuation, and 40 μm diameter silica microspheres were used to induce acoustic backscatter. Phantom vessels consisting of thin-walled polydimethylsiloxane tubing were embedded at depths of 2–6 mm beneath the skin, and blood mimicking fluid was passed through the vessels. The phantoms were characterized through uniaxial compression and tension experiments, rheological frequency sweep studies, diffuse reflectance spectroscopy, and ultrasonic pulse-echo measurements. Results were then compared to in vivo and ex vivo literature data. Results: The elastic and dynamic shear behavior of the phantom skin layers and vessel wall closely approximated the behavior of porcine skin tissues and human vessels. Similarly, the optical properties of the phantom tissue components in the wavelength range of 400–1100 nm, as well as the acoustic properties in the frequency range of 2–9 MHz, were comparable to human tissue data. Normalized root mean square percent errors between the phantom results and the literature reference values ranged from 1.06% to 9.82%, which for many measurements were less than the sample variability. Finally, the mechanical and imaging characteristics of the phantoms were found to remain stable after 30 days of storage at 21 °C. Conclusions: The phantoms described in this

  11. Geomorphic Response to Crustal Evolution of the Plate Boundary, northern California

    Science.gov (United States)

    Shi, X.; Kirby, E.; Furlong, K. P.

    2009-12-01

    The Coast Ranges in northern California are located within a developing transform plate boundary (San Andreas-Maacama-Bartlett Springs strike slip faults) and experience a crustal evolution driven by the migration of the Mendocino Triple Junction. How the landscape responds to the evolution of this plate boundary, however, is uncertain. Here, we analyze channel longitudinal profiles developed throughout the Coast Ranges to investigate the link between surface and deeper-seated processes. In particular, we focus on a crustal transition zone centered around the Little Lake Valley (Willits). Using the USGS 10m DEM to extract longitudinal stream profiles, we identify knickpoints and their spatial positions, calculate channel steepnesses and concavities, and analyze the pattern of knickpoint migration to explore possible driving mechanisms for landscape evolution. Our results reveal two first-order “domains” in the Coast Ranges. West of the Maacama fault system, drainages exhibit smooth, concave-up profiles with no discernable knickpoints. Preservation of relict patches of a high-elevation, low-relief landscape along the drainage divide between these coastal streams and inland watersheds (Eel and Russian Rivers) is consistent with progressive emergence of this region from below sea level, as indicated by relict shallow marine deposits (Ohlson Ranch Formation). East of the divide, tributaries of the Russian and Eel rivers exhibit knickpoints that separate downstream reaches of high gradient from lower-gradient headwater reaches. These are interpreted to reflect a transient increase in incision rates following either 1) stream capture, or 2) local vertical movements along the Maacama fault system. An example of this is found in the region east of Little Lake Valley, drainages are beheaded along the range front fault bounding the eastern side of the valley, suggesting relatively recent west-side down displacement along this fault system. Overall, our analysis suggests

  12. Coupling models of crustal deformation and mantle convection: An application of GeoFramework

    Science.gov (United States)

    Choi, E.; Thoutireddy, P.; Lavier, L.; Quenette, S.; Tan, E.; Gurnis, M.; Aivazis, M.; Appelbe, B.

    2004-12-01

    Crustal and mantle deformation are two closely coupled dynamical systems, usually solved in isolation. To numerically solve this problem, it is desirable to have both the crust and mantle as active components of the dynamics. However, materials composing the crust and mantle respond to loading differently and two different constitutive relations are necessary to describe the rheology of this system. Deformations also occur over a wide range of length scales: from a few 100 m for fault zones to well over 104 km for the largest scales involved in mantle convection. As a result, the numerical cost for a single model to resolve all of these spatial features while also incorporating distinct material types is prohibitive. Coupling two distinct modeling codes within a computational framework is a natural avenue to tackle the multi-material and multi-scale dynamics associated with the crust-mantle system. Using GeoFramework (http://geoframework.org), an extension of the Pyre, Python-based modeling framework, the SNAC and CitcomS codes are dynamically coupled. CitcomS has been used in variety of studies of mantle convection; this finite element package has been entirely reengineered within the Pyre environment. SNAC is based on the FLAC algorithm and is well-suited to modeling crustal deformation because it can deal with linear elastic, Maxwell viscoelastic, or elastoplastic rheology with a Mohr-Coulomb criterion. Using the Pyre-coupled SNAC and CitcomS codes, we run 3D numerical experiments of the extension of lithosphere in the presence of a rising mantle plume within a regional spherical geometry. The full thickness of the crust is simulated with SNAC and mantle convection with CitcomS. In the far field, deformation is partly driven by prescribed velocities described by two diverging plates around a single Euler pole. This specific setting for the problem is intended to help understand the evolution of the Red Sea and Afar triple junction. We will show the dynamic

  13. Report on DELP 1988 Cruises in the Okinawa Trough : Part 3. Crustal structure of the southern Okinawa Trough

    OpenAIRE

    Hirata, Naoshi; Kinoshita, Hajimu; Katao, Hiroshi; Baba, Hisatoshi; Kaiho, Yuka; Koresawa, Sadayuki; Ono, Yuichiro; Hayashi, Kohichi

    1991-01-01

    A refraction seismic experiment was conducted in the southern Okinawa Trough to study the crustal structure of a back-arc basin. We deployed 18 ocean bottom seismometers (OBSs) every 11km along a 195-km profile. We shot three large explosives (600kg, 500kg, and 450 kg) and 50 small explosives (50 kg and 25 kg). The explosions were complemented by shots from an array of a 9-liter airgun and a 16-liter airgun. The average shot interval of the explosives was 3.8 km, and that of the airguns was 1...

  14. Tissue-mimicking phantoms for photoacoustic and ultrasonic imaging

    Science.gov (United States)

    Cook, Jason R.; Bouchard, Richard R.; Emelianov, Stanislav Y.

    2011-01-01

    In both photoacoustic (PA) and ultrasonic (US) imaging, overall image quality is influenced by the optical and acoustical properties of the medium. Consequently, with the increased use of combined PA and US (PAUS) imaging in preclinical and clinical applications, the ability to provide phantoms that are capable of mimicking desired properties of soft tissues is critical. To this end, gelatin-based phantoms were constructed with various additives to provide realistic acoustic and optical properties. Forty-micron, spherical silica particles were used to induce acoustic scattering, Intralipid® 20% IV fat emulsion was employed to enhance optical scattering and ultrasonic attenuation, while India Ink, Direct Red 81, and Evans blue dyes were utilized to achieve optical absorption typical of soft tissues. The following parameters were then measured in each phantom formulation: speed of sound, acoustic attenuation (from 6 to 22 MHz), acoustic backscatter coefficient (from 6 to 22 MHz), optical absorption (from 400 nm to 1300 nm), and optical scattering (from 400 nm to 1300 nm). Results from these measurements were then compared to similar measurements, which are offered by the literature, for various soft tissue types. Based on these comparisons, it was shown that a reasonably accurate tissue-mimicking phantom could be constructed using a gelatin base with the aforementioned additives. Thus, it is possible to construct a phantom that mimics specific tissue acoustical and/or optical properties for the purpose of PAUS imaging studies. PMID:22076278

  15. Spontaneous motor entrainment to music in multiple vocal mimicking species.

    Science.gov (United States)

    Schachner, Adena; Brady, Timothy F; Pepperberg, Irene M; Hauser, Marc D

    2009-05-26

    The human capacity for music consists of certain core phenomena, including the tendency to entrain, or align movement, to an external auditory pulse [1-3]. This ability, fundamental both for music production and for coordinated dance, has been repeatedly highlighted as uniquely human [4-11]. However, it has recently been hypothesized that entrainment evolved as a by-product of vocal mimicry, generating the strong prediction that only vocal mimicking animals may be able to entrain [12, 13]. Here we provide comparative data demonstrating the existence of two proficient vocal mimicking nonhuman animals (parrots) that entrain to music, spontaneously producing synchronized movements resembling human dance. We also provide an extensive comparative data set from a global video database systematically analyzed for evidence of entrainment in hundreds of species both capable and incapable of vocal mimicry. Despite the higher representation of vocal nonmimics in the database and comparable exposure of mimics and nonmimics to humans and music, only vocal mimics showed evidence of entrainment. We conclude that entrainment is not unique to humans and that the distribution of entrainment across species supports the hypothesis that entrainment evolved as a by-product of selection for vocal mimicry.

  16. Demodex folliculitis mimicking acute graft-vs-host disease.

    Science.gov (United States)

    Cotliar, Jonathan; Frankfurt, Olga

    2013-12-01

    Acute graft-vs-host disease (GVHD) typically requires high-dose systemic steroids as first-line treatment. Like drug eruptions, viral exanthema, and toxic erythema of chemotherapy, Demodex folliculitis is a clinical mimicker of acute GVHD and requires nonimmunosuppressive therapy. This case of Demodex folliculitis mimicking acute GVHD highlights the need for skin biopsy in patients who have undergone a stem cell transplant with eruptions on the head and neck. A 46-year-old white woman with a history of Fms-like tyrosine kinase 3 acute myeloid leukemia presented to the dermatology clinic with a 5-day history of a nonpruritic eruption on her face and neck 28 days after undergoing a double umbilical cord blood hematopoietic stem cell transplant (HSCT). Findings from the skin biopsy demonstrated a deep dermal lymphocytic infiltrate adjacent to follicular units along with an abundance of Demodex mites noted within the hair follicles consistent with Demodex folliculitis. Oral ivermectin, 12 mg, was given, and the eruption cleared within 24 hours. To our knowledge, this is only the fifth reported case of Demodex folliculitis following HSCT, but the first ever reported to be successfully treated with oral ivermectin. Demodex folliculitis should be added to the differential diagnosis of skin eruptions that arise after HSCT.

  17. A reverse energy cascade for crustal magma transport

    Science.gov (United States)

    Karlstrom, Leif; Paterson, Scott R.; Jellinek, A. Mark

    2017-08-01

    Direct constraints on the ascent, storage and eruption of mantle melts come primarily from exhumed, long-frozen intrusions. These structures, relics of a dynamic magma transport network, encode how Earth's crust grows and differentiates over time. Furthermore, they connect mantle melting to an evolving distribution of surface volcanism. Disentangling magma transport processes from the plutonic record is consequently a seminal but unsolved problem. Here we use field data analyses, scaling theory and numerical simulations to show that the size distribution of intrusions preserved as plutonic complexes in the North American Cordillera suggests a transition in the mechanical response of crustal rocks to protracted episodes of magmatism. Intrusion sizes larger than about 100 m follow a power-law scaling expected if energy delivered from the mantle to open very thin dykes and sills is transferred to intrusions of increasing size. Merging, assimilation and mixing of small intrusions into larger ones occurs until irreversible deformation and solidification dissipate available energy. Mantle magma supply over tens to hundreds of thousands of years will trigger this regime, a type of reverse energy cascade, depending on the influx rate and efficiency of crustal heating by intrusions. Identifying regimes of magma transport provides a framework for inferring subsurface magmatic processes from surface patterns of volcanism, information preservation in the plutonic record, and related effects including climate.

  18. Crustal velocities from geodetic very long baseline interferometry

    Science.gov (United States)

    Fallon, F. W.; Dillinger, W. H.

    1992-05-01

    VLBI observations from the International Radio Interferometric Surveying and Crustal Dynamics Projects programs taken over a span of 5-8 yr (through August 1990) are used to derive relative velocities of 16 sites on the North American, Eurasian, Pacific, and African plates. The data reduction scheme simultaneously estimates earth orientation parameters and nutation for each session, local atmosphere and clock correction terms, source positions, and initial site positions, as well as the site velocities. Instead of an a priori geophysical crustal model, a minimal set of geometric constraints is used to obtain the velocities. Two alternative constraint formulations - setting the secular motion of the pole and mean length of day to fixed values, and fixing the net rotation of the sites - are considered. They are shown to be equivalent in that they yield equivalent velocity sets with allowance for translation and rotation. The resulting velocities have formal standard errors typically less than 0.2 cm/yr, and most velocities are significantly different from zero.

  19. A view into crustal evolution at mantle depths

    Science.gov (United States)

    Kooijman, Ellen; Smit, Matthijs A.; Ratschbacher, Lothar; Kylander-Clark, Andrew R. C.

    2017-05-01

    Crustal foundering is an important mechanism in the differentiation and recycling of continental crust. Nevertheless, little is known about the dynamics of the lower crust, the temporal scale of foundering and its role in the dynamics of active margins and orogens. This particularly applies to active settings where the lower crust is typically still buried and direct access is not possible. Crustal xenoliths derived from mantle depth in the Pamir provide a unique exception to this. The rocks are well-preserved and comprise a diverse set of lithologies, many of which re-equilibrated at high-pressure conditions before being erupted in their ultrapotassic host lavas. In this study, we explore the petrological and chronological record of eclogite and felsic granulite xenoliths. We utilized accessory minerals - zircon, monazite and rutile - for coupled in-situ trace-element analysis and U-(Th-)Pb chronology by laser-ablation (split-stream) inductively coupled plasma mass spectrometry. Each integrated analysis was done on single mineral zones and was performed in-situ in thin section to maintain textural context and the ability to interpret the data in this framework. Rutile thermo-chronology exclusively reflects eruption (11.17 ± 0.06Ma), which demonstrates the reliability of the U-Pb rutile thermo-chronometer and its ability to date magmatic processes. Conversely, zircon and monazite reveal a series of discrete age clusters between 55-11 Ma, with the youngest being identical to the age of eruption. Matching age populations between samples, despite a lack of overlapping ages for different chronometers within samples, exhibit the effectiveness of our multi-mineral approach. The REE systematics and age data for zircon and monazite, and Ti-in-zircon data together track the history of the rocks at a million-year resolution. The data reveal that the rocks resided at 30-40 km depth along a stable continental geotherm at 720-750 °C until 24-20 Ma, and were subsequently

  20. Small intestinal bacterial overgrowth mimicking acute flare as a pitfall in patients with Crohn's Disease

    Directory of Open Access Journals (Sweden)

    Reinshagen Max

    2009-07-01

    Full Text Available Abstract Background Small intestinal bacterial overgrowth (SIBO is characterized by excessive proliferation of colonic bacterial species in the small bowel. Potential causes of SIBO include fistulae, strictures or motility disturbances. Hence, patients with Crohn's Disease (CD are especially predisposed to develop SIBO. As result, CD patients may experience malabsorption and report symptoms such as weight loss, watery diarrhea, meteorism, flatulence and abdominal pain, mimicking acute flare in these patients. Methods One-hundred-fifty patients with CD reporting increased stool frequency, meteorism and/or abdominal pain were prospectively evaluated for SIBO with the Hydrogen Glucose Breath Test (HGBT. Results Thirty-eight patients (25.3% were diagnosed with SIBO based on positive findings at HGBT. SIBO patients reported a higher rate of abdominal complaints and exhibited increased stool frequency (5.9 vs. 3.7 bowel movements/day, p = 0.003 and lower body weight (63.6 vs 70.4 kg, p = 0.014. There was no correlation with the Crohn's Disease Activity Index. SIBO was significantly more frequent in patients with partial resection of the colon or multiple intestinal surgeries; there was also a clear trend in patients with ileocecal resection that did not reach statistical significance. SIBO rate was also higher in patients with affection of both the colon and small bowel, while inflammation of the (neoterminal ileum again showed only tendential association with the development of SIBO. Conclusion SIBO represents a frequently ignored yet clinically relevant complication in CD, often mimicking acute flare. Because symptoms of SIBO are often difficult to differentiate from those caused by the underlying disease, targeted work-up is recommended in patients with corresponding clinical signs and predisposing factors.

  1. Crustal structure of the Iberian Peninsula and surrounding regions from ambient noise tomography

    Science.gov (United States)

    Villasenor, A.

    2015-12-01

    We present new high-resolution images of the crust in the Iberian Peninsula and surrounding regions using seismic ambient noise. We have compiled continuous recordings of all permanent broadband stations and temporary experiments in the region (IberArray, WILAS, PYROPE, PICASSO) from 2007 to 2014. This dataset consists of more than 400 broadband stations, although not all of them were operating simultaneously. We cross-correlate the three components these continuous recordings between all station pairs to obtain empirical Green's functions (EFGs). From these EGFs we measure group and phase velocities of the fundamental mode Rayleigh and Love waves, and also obtain estimates of Rayleigh wave ellipticity. We then perform a 2D tomographic inversion of the dispersion measurements to obtain phase and group velocity maps of Rayleigh and Love waves for periods from 4 to 40 seconds. The short period dispersion and ellipticity maps show excellent correlation with surface features (i.e. sedimentary basins, internal zones of mountain ranges, and stable regions), while maps for longer periods are a good proxy for crustal thickness. Due to the high station density of the dataset used we are able to image the entire Iberian Peninsula with unprecedented resolution, resolving small scale structures such as the West Alboran and Lower Tagus basins, the high anomaly associated with the Ronda-Beni Bousera peridotites, etc. We also investigate the existence of azimuthal anisotropy of Rayleigh wave velocities as a function of period (i.e. depth) . Given the good correlation of the new dispersion maps with gravity anomalies, estimates of crustal thickness from receiver functions, and P-wave velocities from local earthquake tomography, our ultimate objective is to obtain an integrated model of shear-wave structure that fits all these datasets.

  2. Multi-dimensional Crustal and Lithospheric Structure of the Atlas Mountains of Morocco by Magnetotelluric Imaging

    Science.gov (United States)

    Kiyan, D.; Jones, A. G.; Fullea, J.; Ledo, J.; Siniscalchi, A.; Romano, G.

    2014-12-01

    The PICASSO (Program to Investigate Convective Alboran Sea System Overturn) project and the concomitant TopoMed (Plate re-organization in the western Mediterranean: Lithospheric causes and topographic consequences - an ESF EUROSCORES TOPO-EUROPE project) project were designed to collect high resolution, multi-disciplinary lithospheric scale data in order to understand the tectonic evolution and lithospheric structure of the western Mediterranean. The over-arching objectives of the magnetotelluric (MT) component of the projects are (i) to provide new electrical conductivity constraints on the crustal and lithospheric structure of the Atlas Mountains, and (ii) to test the hypotheses for explaining the purported lithospheric cavity beneath the Middle and High Atlas inferred from potential-field lithospheric modeling. We present the results of an MT experiment we carried out in Morocco along two profiles: an approximately N-S oriented profile crossing the Middle Atlas, the High Atlas and the eastern Anti-Atlas to the east (called the MEK profile, for Meknes) and NE-SW oriented profile through western High Atlas to the west (called the MAR profile, for Marrakech). Our results are derived from three-dimensional (3-D) MT inversion of the MT data set employing the parallel version of Modular system for Electromagnetic inversion (ModEM) code. The distinct conductivity differences between the Middle-High Atlas (conductive) and the Anti-Atlas (resistive) correlates with the South Atlas Front fault, the depth extent of which appears to be limited to the uppermost mantle (approx. 60 km). In all inverse solutions, the crust and the upper mantle show resistive signatures (approx. 1,000 Ωm) beneath the Anti-Atlas, which is the part of stable West African Craton. Partial melt and/or exotic fluids enriched in volatiles produced by the melt can account for the high middle to lower crustal and uppermost mantle conductivity in the Folded Middle Atlas, the High Moulouya Plain and the

  3. Crustal structure and regional tectonics of SE Sweden and the Baltic Sea

    Energy Technology Data Exchange (ETDEWEB)

    Milnes, A.G. [Bergen Univ. (Norway). Dept. of Geology; Gee, D.G.; Lund, C.E. [Uppsala Univ. (Sweden). Dept. of Earth Sciences

    1998-11-01

    In this desk study, the available geophysical and geological data on the crustal structure and regional tectonics of the wider surroundings of the Aespoe site (SE Sweden and adjacent parts of the Baltic Sea) are compiled and assessed. The aim is to contribute to the knowledge base for long-term rock mechanical modeling, using the Aespoe site as a proxy for a high-level radioactive waste repository site in Swedish bedrock. The geophysical data reviewed includes two new refraction/wide-angle reflection seismic experiments carried out within the EUROBRIDGE project, in addition to the numerous earlier refraction seismic profiles. The BABEL normal-incidence deep seismic profile is also considered. New geological data, presented at EUROBRIDGE workshops, and in recent SGU publications, are reviewed for the same area. In combination with the seismic data, these provide a base for interpreting the present composition and structure, and the Palaeoproterozoic-Mesoproterozoic evolution, of the crustal segment within which the Aespoe site lies - the Smaaland mega-block. This is characterized by having undergone little regionally significant deformation or magmatism since Neoproterozoic times (the last 1000 million years). It is shown that, at this scale of observation (of the order of 100 km), the long-term rheology of the lithosphere can be argued from a relatively tight observational network, when combined with the results of earlier SKB studies (seismo-tectonics, uplift patterns, state of stress, heat flow) and published research. Although many uncertainties exist, the present state of knowledge would suffice for first exploratory calculations and sensitivity studies of long-term, large-scale rock mechanics 101 refs, 22 figs

  4. Crustal structure and rift tectonics across the Cauvery–Palar basin, eastern continental margin of India based on seismic and potential field modelling

    Digital Repository Service at National Institute of Oceanography (India)

    Twinkle, D.; Rao, G.S.; Radhakrishna, M.; Murthy, K.S.R.

    Cauvery–Palar basin. The 2D gravity and magnetic crustal models indicate several crustal blocks separated by major structures or faults, and the rift-related volcanic intrusive rocks that characterize the basin. The crustal models further reveal...

  5. Mimicry in social interaction: Benefits for mimickers, mimickees, and their interaction

    NARCIS (Netherlands)

    Stel, M.; Vonk, R.

    2010-01-01

    Mimicry has benefits for people in social interactions. However, evidence regarding the consequences of mimicry is incomplete. First, research on mimicry has particularly focused on effects of being mimicked. Secondly, on the side of the mimicker evidence is correlational or lacks real interaction

  6. Tax mimicking and yardstick competition among local governments in the Netherlands

    NARCIS (Netherlands)

    Allers, MA; Elhorst, JP

    This paper provides a spatial-econometric analysis of the setting of property tax rates by Dutch municipalities. We find evidence of tax mimicking: a ten percent higher property tax rate in neighboring municipalities leads to a 3.5 percent higher tax rate. Mimicking is less pronounced in

  7. Quantifying Crustal Thickness in Continental Collisional Belts: Global Perspective and a Geologic Application.

    Science.gov (United States)

    Hu, Fangyang; Ducea, Mihai N; Liu, Shuwen; Chapman, James B

    2017-08-01

    We present compiled geochemical data of young (mostly Pliocene-present) intermediate magmatic rocks from continental collisional belts and correlations between their whole-rock Sr/Y and La/Yb ratios and modern crustal thickness. These correlations, which are similar to those obtained from subduction-related magmatic arcs, confirm that geochemistry can be used to track changes of crustal thickness changes in ancient collisional belts. Using these results, we investigate temporal variations of crustal thickness in the Qinling Orogenic Belt in mainland China. Our results suggest that crustal thickness remained constant in the North Qinling Belt (~45-55 km) during the Triassic to Jurassic but fluctuates in the South Qinling Belt, corresponding to independently determined tectonic changes. In the South Qinling Belt, crustal thickening began at ~240 Ma and culminated with 60-70-km-thick crust at ~215 Ma. Then crustal thickness decreased to ~45 km at ~200 Ma and remained the same to the present. We propose that coupled use of Sr/Y and La/Yb is a feasible method for reconstructing crustal thickness through time in continental collisional belts. The combination of the empirical relationship in this study with that from subduction-related arcs can provide the crustal thickness evolution of an orogen from oceanic subduction to continental collision.

  8. Crustal and upper mantle structure of Siberia from teleseismic receiver functions

    DEFF Research Database (Denmark)

    Soliman, Mohammad Youssof Ahmad; Thybo, Hans; Artemieva, Irina

    2015-01-01

    . The current results of RF analysis of the crustal and mantle structure will help to build a model for tectonic and geodynamic evolution of different provinces of Siberia. We compare our results to the recent detailed models of crustal structure in the area and with seismic models for similar geodynamic...

  9. Satellite gravity anomalies and crustal features of the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, D.G.; Krishna, K.S.; Neprochnov, Y.P.; Grinko, B.N.

    Satellite free-air gravity anomaly contour map at 5 mGal interval, seismic reflection and bathymetric data lead to the identification of deformed crustal structure of the Central Indian Ocean Basin. Twenty-three NE-SW trending deformed crustal...

  10. Modeling Crustal Thickness Variations Beneath the East Pacific Rise: Mantle Diapirs or Plate Kinematics?

    Science.gov (United States)

    George, S. A.; Toomey, D. R.

    2003-12-01

    Geophysical studies along the East Pacific Rise between the Siqueiros and Clipperton fracture zones reveal along- and cross-axis variations in crustal thickness whose origins are poorly understood. By one view, variations in crustal thickness are the result of three-dimensional upwelling of the mantle associated with a melt-rich diapir centered at 9° 50'N. Alternatively, it has been proposed that the migration of the 9° 03'N overlapping spreading center (OSC) alters the thickness of crust by increasing the amount of time that a crustal unit resides near the spreading axis. In this case, crustal thickness variations arise from plate kinematics, and not from three-dimensional variations in mantle upwelling. We report on a modeling study designed to explore how the evolution of OSCs may alter the thickness of newly-formed crust. OSC propagation is modeled using the kinematic algorithm developed by Wilson [1990], modified to track parcels of crust through time. Given an OSC's kinematic history and two-dimensional descriptions of the melt flux out of the mantle (i.e. invariant along the rise), we predict relative variations in crustal thickness. Our modeling assumes that underplating increases the thickness of the crust and/or Moho transition zone as long as a crustal unit resides over the source of mantle-derived melt. Results suggest two general kinematic mechanisms whereby variations in crustal thickness can occur: those due to an offset between the mantle-level magmatic system and the spreading axis, and those due to any relative reduction in the velocity of a crustal unit as it moves off axis. Offset-induced crustal thickness variations are manifest as long-wavelength ( ˜50 km), low-amplitude cross-axis asymmetries. Local slowing of crustal units as they move off axis -- in direct association with the OSC and its overlap basins -- results in relatively short-wavelength ( ˜10 km), high-amplitude variations in crustal thickness. Using a kinematic history

  11. Crustal stress pattern in China and its adjacent areas

    Science.gov (United States)

    Hu, Xingping; Zang, Arno; Heidbach, Oliver; Cui, Xiaofeng; Xie, Furen; Chen, Jiawei

    2017-11-01

    During the update of the World Stress Map (WSM) database, we integrated the China stress database by strictly using the internationally developed quality ranking scheme for each individual stress data record. This effort resulted in a comprehensive and reliable dataset for the crustal stress of China and its adjacent areas with almost double the amount of data records from the WSM database release 2008, i.e., a total of 8228 data records with reliable A-C qualities in the region of 45-155° East and 0-60° North. We use this dataset for an analysis of the stress pattern for the orientation of maximum compressive horizontal stress (SHmax). In contrast to earlier findings that suggested that the mean SHmax orientation would be aligned with the direction of plate motion, we clearly see from our results that the plate boundary forces, as well as topography and faulting, are important control factors for the overall stress pattern. Furthermore, the smoothing results indicate that the SHmax orientation in China rotates clockwise from the west to the east, which results in a fan-shaped crustal stress pattern for the continental scale. The plate boundary forces around China, which are the Indian-Eurasian plate collision in the west and the Pacific plate subduction and the push from the Philippine plate in the east, can still be seen as the key driving processes and the first-order controls for the crustal stress pattern. The South-North seismic zone can be seen as the separation zone for the western and eastern plate boundary forces. Topographic variation and faulting activity, however, provide second-order changes, and lead to local variations and different inhomogeneity scales for the stress pattern. Due to differences in these factors, Northeast China and the central part of the Tibetan plateau have notably homogeneous stress patterns, while the South-North seismic zone, the Hindu Kush-Pamir region, and the Taiwan region have extremely inhomogeneous stress patterns

  12. A global estimate of the Earth's magnetic crustal thickness

    Science.gov (United States)

    Vervelidou, Foteini; Thébault, Erwan

    2014-05-01

    The Earth's lithosphere is considered to be magnetic only down to the Curie isotherm. Therefore the Curie isotherm can, in principle, be estimated by analysis of magnetic data. Here, we propose such an analysis in the spectral domain by means of a newly introduced regional spatial power spectrum. This spectrum is based on the Revised Spherical Cap Harmonic Analysis (R-SCHA) formalism (Thébault et al., 2006). We briefly discuss its properties and its relationship with the Spherical Harmonic spatial power spectrum. This relationship allows us to adapt any theoretical expression of the lithospheric field power spectrum expressed in Spherical Harmonic degrees to the regional formulation. We compared previously published statistical expressions (Jackson, 1994 ; Voorhies et al., 2002) to the recent lithospheric field models derived from the CHAMP and airborne measurements and we finally developed a new statistical form for the power spectrum of the Earth's magnetic lithosphere that we think provides more consistent results. This expression depends on the mean magnetization, the mean crustal thickness and a power law value that describes the amount of spatial correlation of the sources. In this study, we make a combine use of the R-SCHA surface power spectrum and this statistical form. We conduct a series of regional spectral analyses for the entire Earth. For each region, we estimate the R-SCHA surface power spectrum of the NGDC-720 Spherical Harmonic model (Maus, 2010). We then fit each of these observational spectra to the statistical expression of the power spectrum of the Earth's lithosphere. By doing so, we estimate the large wavelengths of the magnetic crustal thickness on a global scale that are not accessible directly from the magnetic measurements due to the masking core field. We then discuss these results and compare them to the results we obtained by conducting a similar spectral analysis, but this time in the cartesian coordinates, by means of a published

  13. Combined Gravimetric-Seismic Crustal Model for Antarctica

    Science.gov (United States)

    Baranov, Alexey; Tenzer, Robert; Bagherbandi, Mohammad

    2017-09-01

    The latest seismic data and improved information about the subglacial bedrock relief are used in this study to estimate the sediment and crustal thickness under the Antarctic continent. Since large parts of Antarctica are not yet covered by seismic surveys, the gravity and crustal structure models are used to interpolate the Moho information where seismic data are missing. The gravity information is also extended offshore to detect the Moho under continental margins and neighboring oceanic crust. The processing strategy involves the solution to the Vening Meinesz-Moritz's inverse problem of isostasy constrained on seismic data. A comparison of our new results with existing studies indicates a substantial improvement in the sediment and crustal models. The seismic data analysis shows significant sediment accumulations in Antarctica, with broad sedimentary basins. According to our result, the maximum sediment thickness in Antarctica is about 15 km under Filchner-Ronne Ice Shelf. The Moho relief closely resembles major geological and tectonic features. A rather thick continental crust of East Antarctic Craton is separated from a complex geological/tectonic structure of West Antarctica by the Transantarctic Mountains. The average Moho depth of 34.1 km under the Antarctic continent slightly differs from previous estimates. A maximum Moho deepening of 58.2 km under the Gamburtsev Subglacial Mountains in East Antarctica confirmed the presence of deep and compact orogenic roots. Another large Moho depth in East Antarctica is detected under Dronning Maud Land with two orogenic roots under Wohlthat Massif (48-50 km) and the Kottas Mountains (48-50 km) that are separated by a relatively thin crust along Jutulstraumen Rift. The Moho depth under central parts of the Transantarctic Mountains reaches 46 km. The maximum Moho deepening (34-38 km) in West Antarctica is under the Antarctic Peninsula. The Moho depth minima in East Antarctica are found under the Lambert Trench (24

  14. Combined Gravimetric-Seismic Crustal Model for Antarctica

    Science.gov (United States)

    Baranov, Alexey; Tenzer, Robert; Bagherbandi, Mohammad

    2018-01-01

    The latest seismic data and improved information about the subglacial bedrock relief are used in this study to estimate the sediment and crustal thickness under the Antarctic continent. Since large parts of Antarctica are not yet covered by seismic surveys, the gravity and crustal structure models are used to interpolate the Moho information where seismic data are missing. The gravity information is also extended offshore to detect the Moho under continental margins and neighboring oceanic crust. The processing strategy involves the solution to the Vening Meinesz-Moritz's inverse problem of isostasy constrained on seismic data. A comparison of our new results with existing studies indicates a substantial improvement in the sediment and crustal models. The seismic data analysis shows significant sediment accumulations in Antarctica, with broad sedimentary basins. According to our result, the maximum sediment thickness in Antarctica is about 15 km under Filchner-Ronne Ice Shelf. The Moho relief closely resembles major geological and tectonic features. A rather thick continental crust of East Antarctic Craton is separated from a complex geological/tectonic structure of West Antarctica by the Transantarctic Mountains. The average Moho depth of 34.1 km under the Antarctic continent slightly differs from previous estimates. A maximum Moho deepening of 58.2 km under the Gamburtsev Subglacial Mountains in East Antarctica confirmed the presence of deep and compact orogenic roots. Another large Moho depth in East Antarctica is detected under Dronning Maud Land with two orogenic roots under Wohlthat Massif (48-50 km) and the Kottas Mountains (48-50 km) that are separated by a relatively thin crust along Jutulstraumen Rift. The Moho depth under central parts of the Transantarctic Mountains reaches 46 km. The maximum Moho deepening (34-38 km) in West Antarctica is under the Antarctic Peninsula. The Moho depth minima in East Antarctica are found under the Lambert Trench (24

  15. [A Case of Intracranial Localized Castleman's Disease Mimicking Convexity Meningioma].

    Science.gov (United States)

    Ozono, Keisuke; Fujimoto, Takashi; Hirose, Makoto; Kawahara, Ichiro; Uchihashi, Kazuyoshi

    2017-01-01

    A 68-year-old man presented with abnormal behavior and Todd's paralysis on the right side after having taken a bath. Computed tomography and magnetic resonance imaging revealed a tumor mimicking convexity meningioma that had a perifocal edema, although its mass was not very large. The patient underwent surgery, and full recovery was achieved following a total removal of the lesion. Pathohistological examination demonstrated an intermediate type of Castleman's disease. The final diagnosis was intracranial localized Castleman's disease because the results of the full physical examination and laboratory analyses were normal. Castleman's disease is a rare lymphoproliferative disorder of unknown etiology. Moreover, intracranial involvement is very rare. In cases of intracranial meningeal tumors with perifocal edema, we should take this disease into consideration in the differential diagnosis.

  16. Dental technician pneumoconiosis mimicking pulmonary tuberculosis: a case report.

    Science.gov (United States)

    Tan, Han Loong; Faisal, Mohamed; Soo, Chun Ian; Ban, Andrea Y L; Manap, Roslina Abdul; Hassan, Tidi M

    2016-09-07

    Dental laboratory technicians are at risk of developing occupational respiratory diseases due to exposure to various potentially toxic substances in their working environment. Since 1939, few cases of silicosis among dental technician have been reported. We illustrate a 38 year-old female, who worked in a dental laboratory for 20 years, initially treated as pulmonary tuberculosis and chronic necrotising aspergillosis without much improvement. Computed tomography guided lung biopsy and bronchoscopic transbronchial lung biopsy were performed. Lung tissue biopsies showed presence of refractile dental materials within the areas of histiocyte proliferation. The diagnosis of dental technician pneumoconiosis was obtained and our patient underwent pulmonary rehabilitation. This case highlights the importance of obtaining a detailed occupational history in tuberculosis endemic area, as pulmonary tuberculosis is a great mimicker of other respiratory diseases.

  17. A syndrome of the dentate nucleus mimicking psychogenic ataxia.

    Science.gov (United States)

    Salih, Farid; Breuer, Eva; Harnack, Daniel; Hoffmann, Karl-Titus; Ploner, Christoph J

    2010-03-15

    To date, cerebellar involvement in control of non-motor functions like cognition and emotion is increasingly well established. Current models suggest that motor and non-motor networks connecting the cerebellum with cortical areas operate independently in closed and segregated loops. Here, we report a 59-year-old female patient with a small cerebellar lesion that shows that cognitive activation can significantly influence cerebellar motor control. Surprisingly, this led to a clinical picture mimicking a psychogenic disorder. Similar to non-human primates, this case suggests that the human dentate nucleus consists of distinct cognitive and motor domains with additional somatotopical arrangement of the latter. Extending current models of cerebro-cerebellar interaction, this case further illustrates that there can be significant functional cross-talk between motor and cognitive cerebellar networks.

  18. Pituitary adenoma with extensive calcaficcations mimicking crainopharyngioma: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Sung Chan; Lee, Seoung Ro; Kwon, Bae Ju; Moon, Won Jin; Jeon, Eui Yong [Hanyang Univ. College of Medicine, Seoul (Korea, Republic of)

    2001-01-01

    A 27-year-old man presented with complaints of headache and visual disturbance, first noted six months earlier. Simple radiographs of skull sellar widening and calcification. Brian CT revealed a 3 x 3 x 4 cm-sized sellar suprasellar mass with heavy calcification. T1-weighted MR images showed that the signal intencity of the mass was slightly lower than that of the gray matter, while T2-weighted images showed heterogeneous high signal intensity with centrl low-signal-intensity foci, suggesting calcification After contrast infusion, enancement was irregular. Surgery revealed a 4 x 5 cm sized, well-demarcated, lobulated mass adhering to the meninges. Papillary-type pituitary adenoma was histologically confirmed. We report the CT and MR findings of atypical pituitary adenoma with extensive internal calcification mimicking craniopharyngioma.

  19. Mimicking biological stress–strain behaviour with synthetic elastomers

    Science.gov (United States)

    Vatankhah-Varnosfaderani, Mohammad; Daniel, William F. M.; Everhart, Matthew H.; Pandya, Ashish A.; Liang, Heyi; Matyjaszewski, Krzysztof; Dobrynin, Andrey V.; Sheiko, Sergei S.

    2017-09-01

    Despite the versatility of synthetic chemistry, certain combinations of mechanical softness, strength, and toughness can be difficult to achieve in a single material. These combinations are, however, commonplace in biological tissues, and are therefore needed for applications such as medical implants, tissue engineering, soft robotics, and wearable electronics. Present materials synthesis strategies are predominantly Edisonian, involving the empirical mixing of assorted monomers, crosslinking schemes, and occluded swelling agents, but this approach yields limited property control. Here we present a general strategy for mimicking the mechanical behaviour of biological materials by precisely encoding their stress–strain curves in solvent-free brush- and comb-like polymer networks (elastomers). The code consists of three independent architectural parameters—network strand length, side-chain length and grafting density. Using prototypical poly(dimethylsiloxane) elastomers, we illustrate how this parametric triplet enables the replication of the strain-stiffening characteristics of jellyfish, lung, and arterial tissues.

  20. Postpolypectomy Electrocoagulation Syndrome: A Mimicker of Colonic Perforation

    Directory of Open Access Journals (Sweden)

    Brian C. Benson

    2013-01-01

    Full Text Available Postpolypectomy electrocoagulation syndrome is a rare complication of polypectomy with electrocautery and is characterized by a transmural burn of the colon wall. Patients typically present within 12 hours after the procedure with symptoms mimicking colonic perforation. Presented is the case of a 56-year-old man who developed abdominal pain six hours after colonoscopy during which polypectomy was performed using snare cautery. CT imaging of the abdomen revealed circumferential thickening of the wall of the transverse colon without evidence of free air. The patient was treated conservatively as an outpatient and had resolution of his pain over the following four days. Recognition of the diagnosis and understanding of the treatment are important to avoid unnecessary exploratory laparotomy or hospitalization.

  1. A rare case of ascending colon actinomycosis mimicking cancer

    Directory of Open Access Journals (Sweden)

    Zizi Diamanto

    2005-01-01

    Full Text Available Abstract Background Actinomycosis is a rare inflammatory disease caused by an anaerobic bacterium that can rarely affect the large intestine. Case presentation We present a rare case of a cecum and ascending colon actinomycosis in a 72 years old woman, mimicking clinically a malignant inflammatory tumor of the right colon. The patient complained of right lower quadrant pain. Although our first thought was a peri-appendiceal abscess, CT scan suggested a right colon tumor. The patient underwent a right colectomy and the histological examination of the specimen revealed colon actinomycosis. Conclusions Preoperative diagnosis in colon actinomycosis is difficult to achieve. Treatment of choice is antibiotics administration. A review of the possible pathogenesis and therapeutic modalities is also presented.

  2. An Adolescent Patient with Scabies Mimicking Gottron Papules

    Directory of Open Access Journals (Sweden)

    Eiji Yoshinaga

    2009-01-01

    Full Text Available Atypical features of scabies occur in infants and children and patients with prolonged use of corticosteroids or immunosuppression. We report a non-immunosuppressed 15-year-old female case of scabies showing scaly reddish papules over the proximal interphalangeal joints mimicking Gottron papules in classic dermatomyositis. Periungal erythema was also seen. Four months’ topical corticosteroids from previous clinics had been used. Dermoscopic findings were consistent with typical pictures of scabies. Scraping of hand crusts demonstrated scabies mites and ova. Skin lesions of the patient were cured with oral ivermectin and topical 10% crotamiton. This case suggests that a lesion resembling Gottron papules may be added to the panel of unusual presentations of scabies.

  3. Myelodysplastic changes mimicking MDS following treatment for osteosarcoma

    DEFF Research Database (Denmark)

    Løhmann, Ditte

    Myelodysplastic changes mimicking MDS following treatment for osteosarcoma Ditte Juel Adolfsen Løhmann, Department of Pediatrics, Aarhus University Hospital, Skejby, Denmark Authors: Ditte Juel Adolfsen Løhmann and Henrik Hasle. Therapy-related myelodysplastic syndrome/acute myeloid leukaemia (t-MDS....../AML) is a feared long-term complication of paediatric cancer including osteosarcoma. Few develop t-MDS/AML, but it is not known how many have significant haematological changes after finishing treatment for osteosarcoma. In this study we reviewed biochemistry from a consecutive series of children for up to two...... MDS (refractory anaemia with excess blasts) with monosomy 7 was found and a hematopoietic stem cell transplant was performed. In the other case MDS without excess of blasts was found and a spontaneous normalization of the biochemistry occurred. In conclusion in our study most patients treated...

  4. Concurrent periosteal chondroma and enchondroma of the fibula mimicking chondrosarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Yasuhiro; Washimi, Osuke; Yamada, Harumoto; Washimi, Yuki; Itoh, Masato [Fujita Health University, Department of Orthopedic Surgery, Toyoake City, Aichi (Japan); Kuroda, Makoto [Fujita Health University, Department of Pathology, Toyoake City, Aichi (Japan)

    2006-05-15

    We present a rare concurrence of enchondroma and periosteal chondroma in the right distal fibula that mimicked chondrosarcoma in a 13-year-old boy. Radiographs and CT scans showed a periosteal lesion producing saucerization without periosteal reaction and calcification in the distal metaphysis of the right fibula. MRI showed an intramedullary lesion adjacent to the periosteal lesion, although it was invisible at CT. There was no cortical breach on imaging and gross examination. Because both lesions represented benign cartilaginous tumors on histology, concurrent periosteal chondroma and enchondroma of the fibula was diagnosed. This combination in the same bone in a patient without enchondromatosis is exceedingly rare. Such imaging features may be confused with those of chondrosarcoma. (orig.)

  5. Malignant Mesothelioma Mimicking Invasive Mammary Carcinoma in a Male Breast

    Directory of Open Access Journals (Sweden)

    Mohamed Mokhtar Desouki

    2015-01-01

    Full Text Available Malignant mesothelioma is an uncommon tumor with strong association with asbestos exposure. Few cases of malignant pleural mesothelioma metastatic to the female breast have been reported. Herein, we presented, for the first time, a case of locally infiltrating malignant pleural mesothelioma forming a mass in the breast of a male as the first pathologically confirmed manifestation of the disease. Breast ultrasound revealed an irregular mass in the right breast which involves the pectoralis muscle. Breast core biopsy revealed a proliferation of neoplastic epithelioid cells mimicking an infiltrating pleomorphic lobular carcinoma. IHC studies showed the cells to be positive for calretinin, CK5/6, WT1, and CK7. The cells were negative for MOC-31, BerEp4, ER, and PR. A final diagnosis of malignant mesothelioma, epithelioid type, was rendered. This case demonstrates the importance of considering a broad differential diagnosis in the setting of atypical presentation with application of a panel of IHC markers.

  6. Enzyme-Mimicking properties of silicates and other minerals

    Science.gov (United States)

    Siegel, B. Z.; Siegel, S. M.

    The adsorptive and/or catalytic properties of clays, silicates in general, and other minerals are well known. More recently, their probable role in prebiotic syntheses of bio-organic compounds has become a matter of record. We demonstrate that, in addition to their role in de novo formation of important biomolecules, clays, micas, fibrous silicates and other minerals mimick the activities of contemporary enzymes including oxidases, esterases, phosphatases and glucosidases. The existence of such capabilities in substances likely to be represented on the surfaces of Earth-like planets may offer a challenge to the technology and design of remote life detection systems which must then distinguish between bona fide biological chemistry and mineral-base pseudometabolism. It also raises questions about the importance of mineral surfaces in post-mortem transformations of organic metabolites in our own biosphere.

  7. Textiloma: A Case of Foreign Body Mimicking a Spinal Tumor.

    Science.gov (United States)

    Meshkini, Ali; Salehpour, Firooz; Rezakhah, Amir; Mirzaei, Farhad; Kazemzadeh, Mohammad; Naseri Alavi, Seyed Ahmad

    2017-11-01

    Case report OBJECTIVE.: To report a case of foreign body mimicking spinal tumor. Gossypiboma or more broadly retained foreign object is a surgical complication resulting from foreign materials such as cotton or gauze pads and surgical sponge, accidentally left inside a patient's body. Such foreign materials cause foreign body reaction in the surrounding tissue. A retrospective case report was performed. Informed consent was obtained from patient. We describe a case of textiloma in which the patient presented with low back pain and radiculopathy 12 years after L5\\S1 discectomy. Imaging revealed a round mass lesion in the sacral space. At the end of surgery, the operative site should be flushed with saline and carefully examined for any foreign materials. 4.

  8. Giant cystic sacral schwannoma mimicking tarlov cyst: a case report.

    Science.gov (United States)

    Attiah, Mark A; Syre, Peter P; Pierce, John; Belyaeva, Elizaveta; Welch, William C

    2016-05-01

    To present a rare case of a giant schwannoma of the sacrum mimicking a Tarlov cyst. A 58-year-old woman had a 1-year history of low back pain. MRI revealed a large cystic mass in the sacral canal with bony erosion. Radiological diagnosis of Tarlov cyst was made. The patient underwent surgical treatment for the lesion, which revealed a solid mass. Histopathological examination of the tumor confirmed the diagnosis of schwannoma. The postoperative course was uneventful and the patient has had significant improvement in her pain 1 month postoperatively. Giant cystic schwannoma of the sacrum is a very rare diagnosis overlooked by practitioners for more common cystic etiologies, but its treatment is significantly different. Care should be taken to include this diagnosis in a differential for a cystic sacral mass.

  9. A Case of Myopericarditis Mimicking Acute Myocardial Infarction in Childhood

    Directory of Open Access Journals (Sweden)

    Rahmi Özdemir

    2015-11-01

    Full Text Available Myopericarditis is an inflammatory disease of the both myocardial and pericardial tissues, and resulting from different etiologies. Viral agents such as coxsackie virus type B, adenovirus, and echovirus are the most common leading cause of this disease and it usually occurs following viral upper respiratory tract infections. Although there are different clinical features according to ages groups, some common findings such as tachycardia incompatible with fever, deeply heared heart sounds, and heart failure can be seen. Clinical findings often mimics a myocardial infarction. Diagnosis of this disease is made by the evaluation of the clinical condition, electrocardiography, echocardiography and elevation of the cardiac enzymes. Because it is mortality, discrimination of myopericarditis from myocardial infarction is very important. Herein, we report a 13 year-old-girl with the diagnosis of myopericarditis presenting with chest pain, electrocardiographic changes mimicking myocardial infarction and elevated cardiac enzymes and also aimed to emphasize the importance of accurate diagnosis of this disease.

  10. Postpartum Unilateral Sacral Stress Fracture Mimicking Lumbar Radiculopathy: Case Report

    Directory of Open Access Journals (Sweden)

    Sinan Bağçacı

    2018-01-01

    Full Text Available Postpartum sacral stress fracture is a very rare clinical entity. Because of the ambiguous clinical and radiological findings, it is often diagnosed late. A case of a postpartal 25-year-old female patient presented with acute onset of low back pain radiating to the right extremity, mimicking lumbar radiculopathy. Magnetic resonance imaging of sacrum revealed a non-displaced stress fracture of the right sacral ala. The 25-hydroxy vitamine D level of the patient was very low; dual energy X-ray absorptiometry measurements were in the normal range. The patient is completely cured as a result of conservative treatment. As a result, sacrum stress fracture should be kept in mind in the presence of back pain during pregnancy and postpartum period.

  11. Adenoid Cystic Carcinoma Mimicking an Oroantral Fistula: A Case Report

    Directory of Open Access Journals (Sweden)

    Monteiro, Bárbara Vanessa de Brito

    2014-01-01

    Full Text Available Introduction Adenoid cystic carcinoma (ACC is one of the most frequent malignant salivary gland tumors, which commonly affects the minor salivary glands of the mouth and is rare in the nose and paranasal sinuses. In the maxillary sinus, ACC can mimic inflammatory diseases and has a poor prognosis. Objective To report a case of a 50-year-old man with ACC of the maxillary sinus whose clinical findings in the alveolar ridge mimicked an oroantral fistula. Case Report An excisional biopsy was performed and histopathologic analysis revealed ACC. Lung metastases and residual tumor in the maxillary sinus were detected by imaging methods. In view of the poor general health of the patient, no new surgical intervention was performed and he was only treated by radiotherapy and follow-up. Conclusion Although rare in the maxillary sinus, ACC should be included in the differential diagnosis of lesions affecting this site.

  12. [Disseminated histoplamosis in adolescent mimicking granulomatosis with polyangiitis].

    Science.gov (United States)

    van Weelden, Marlon; Viola, Gabriela R; Kozu, Katia T; Aikawa, Nadia E; Ivo, Claudia M; Silva, Clovis A

    2015-03-04

    Systemic histoplasmosis is an invasive fungal infection that may mimic primary vasculitis, particularly granulomatosis with polyangiitis (GPA), and was rarely described in adult patients. We reported an immunocompetent patient with disseminated histoplasmosis mimicking GPA who fulfilled European League Against Rheumatism (EULAR)/Pediatric Rheumatology International Trials Organisation (PRINTO)/Pediatric Rheumatology European Society (PRES) validated classification criteria. A 6-year old boy presented acute migratory polyarthritis with spontaneous improvement, sinus inflammation, fever, headache and abdominal pain. Serologic test for hepatitis, cytomegalovirus, human immunodeficiency virus, Epstein-Barr virus, toxoplasmosis, dengue virus and antistreptolysin O were all negative. Magnetic resonance imaging (MRI) showed moderate ascites in pelvis and pansinusitis. Antineutrophil cytoplasmic antibodies (c-ANCA) were positive. He had spontaneous remission of the symptoms including fever. At the age of 11 years and 11 months, he had sinusitis, pneumonia and epididymitis. A month later, he was hospitalized and MRI showed left eye proptosis. Cerebrospinal fluid was normal and indirect tests of fungi were negative. Two months later, he had lumbar pain and computer tomography showed a mass in the right kidney and pulmonary nodule in the right lung. He fulfilled EULAR/PRINTO/PRES criteria for GPA, however the renal biopsy showed a focal granulomatous interstitial nephritis with yeast fungal cells compatible with Histoplasma sp. He was treated with liposomal amphotericin B and itraconazole with improvement of signs and symptoms. We reported a progressive disseminated histoplasmosis case mimicking GPA. Histoplasmosis infection should be considered in immunocompetent subjects with uncommon clinical manifestations, such as arthritis, nephritis and epididymitis. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

  13. Teflon granulomas mimicking cerebellopontine angle tumors following microvascular decompression.

    Science.gov (United States)

    Deep, Nicholas L; Graffeo, Christopher S; Copeland, William R; Link, Michael J; Atkinson, John L; Neff, Brian A; Raghunathan, Aditya; Carlson, Matthew L

    2017-03-01

    To report two patients with a history of microvascular decompression (MVD) for hemifacial spasm who presented with Teflon granulomas (TG) mimicking cerebellopontine angle (CPA) tumors and to perform a systematic review of the English-language literature. Case series at a single tertiary academic referral center and systematic review. Retrospective chart review with analysis of clinical, radiological, and histopathological findings. Systematic review using PubMed, Embase, MEDLINE, and Web of Science databases. Two patients with large skull base TGs mimicking CPA tumors clinically and radiographically were managed at the authors' institution. The first presented 4 years after MVD with asymmetrical sensorineural hearing loss, multiple progressive cranial neuropathies, and brainstem edema due to a growing TG. Reoperation with resection of the granuloma confirmed a foreign-body reaction consisting of multinucleated giant cells containing intracytoplasmic Teflon particles. The second patient presented 11 years after MVD with asymmetrical sensorineural hearing loss and recurrent hemifacial spasm. No growth was noted over 2 years, and the patient has been managed expectantly. Only one prior case of TG after MVD for hemifacial spasm has been reported in the English literature. TG is a rare complication of MVD for hemifacial spasm. The diagnosis should be suspected in patients presenting with a new-onset enhancing mass of the CPA after MVD, even when performed decades earlier. A thorough clinical and surgical history is critical toward establishing an accurate diagnosis to guide management and prevent unnecessary morbidity. Surgical intervention is not required unless progressive neurologic complications ensue. 4 Laryngoscope, 127:715-719, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  14. Acoustical characterization of polysaccharide polymers tissue-mimicking materials.

    Science.gov (United States)

    Cuccaro, Rugiada; Musacchio, Chiara; Giuliano Albo, P Alberto; Troia, Adriano; Lago, Simona

    2015-02-01

    Tissue-mimicking phantoms play a crucial role in medical ultrasound research because they can simulate biological soft tissues. In last years, many types of polymeric tissues have been proposed and characterized from an acoustical and a thermal point of view, but, rarely, a deep discussion about the quality of the measurements, in terms of the uncertainty evaluation, has been reported. In this work, considering the necessity to develop laboratory standards for the measurement of ultrasonic exposure and dose quantities, a detailed description of the experimental apparatuses for the sound speed and the attenuation coefficient measurements is given, focusing the attention on the uncertainty evaluation both of the results and analysis algorithms. In particular, this algorithm reveals a novel empirical relation, fixing a limit to the energy content (therefore limits the number of cycles) of the three parts in which the authors have proposed to divide the acoustical signal. Furthermore, the realisation of multi-components phantoms, Agar and Phytagel based tissue-mimicking gels along with others long chain molecules (dextrane or polyvinyl alcohol) and scattering materials (silicon carbide and kieselguhr) are investigated. This paper reports accurate speed of sound and attenuation coefficient measurements. Speed of sound is measured by a pulse-echo technique in far-field condition, using an optical glass buffer rod; while attenuation coefficient is determined by an insertion technique, using demineralized water as reference material. The experimental sound speed results are subjected to an overall estimated relative uncertainty of about 1.5% and the attenuation coefficient uncertainty is less than 2.5%. For the development of laboratory standards, a detailed analysis of the measurement uncertainty is fundamental to make sample properties comparable. The authors believe this study could represent the right direction to make phantoms characterizations referable and traceable

  15. Moho depth and crustal composition in Southern Africa

    DEFF Research Database (Denmark)

    Soliman, Mohammad Youssof Ahmad; Thybo, Hans; Artemieva, Irina

    2013-01-01

    heterogeneous crustal structure with short wavelength variations in thickness (H), Vp/Vs-ratio (composition), and Moho sharpness, which defines ~20 blocks that do not everywhere coincide with surface tectonic features. In the Zimbabwe Craton, the Tokwe block has H = 35–38 km and Vp/Vs = 1.74–1.79 whereas......-existing lower crust, which is further supported by a very sharp Moho transition. The exposed cross-section in the Vredefort impact crater is non-representative of cratonic crust due to shallowMoho (34 km) and high Vp/Vs ~ 1.80 attributed to shock metamorphism. High Vp/Vs = 1.76 is typical of the Witwatersrand...

  16. Kinematics of the Sierra Nevada and Oregon Crustal Blocks

    Science.gov (United States)

    Vollick, J. J.; McCaffrey, R.; Sella, G.

    2004-12-01

    Northern California contains the intersection of the NW moving Sierra Nevada block and the clockwise rotating Oregon block. Adding to the tectonic complexity of the region are the interactions of the Pacific plate, Basin and Range, California Coast Ranges, Mendocino fracture zone, San Andreas fault and the Juan de Fuca plate. Our research focuses on how the interactions of these features influence the motions of the Oregon and Sierra Nevada blocks. We processed Global Positioning System (GPS) data collected during the 1998 and 1999 National Geodetic Survey High Accuracy Reference Network (HARN) surveys and by us in 2003. Our preliminary analysis of the velocity field indicates that the Oregon crustal block is rotating clockwise relative to the Sierra Nevada block around a pole approximately west of the Mendocino Triple Junction. Our future work involves finding a more exact location of the relative pole rotation between the blocks, the degree of rotation, and how this motion is being taken up.

  17. Variations and controls on crustal thermal regimes in Southeastern Australia

    Science.gov (United States)

    Mather, Ben; McLaren, Sandra; Taylor, David; Roy, Sukanta; Moresi, Louis

    2018-01-01

    The surface heat flow field in Australia has for many years been poorly constrained compared to continental regions elsewhere. 182 recent heat flow determinations and 66 new heat production measurements for Southeastern Australia significantly increase our understanding of local and regional lithospheric thermal regimes and allow for detailed thermal modelling. The new data give a mean surface heat flow for Victoria of 71 ± 15 mW m- 2 which fits within the 61-77 mW m- 2 range reported for Phanerozoic-aged crust globally. These data reveal three new thermally and compositionally distinct heat flow sub-provinces within the previously defined Eastern Heat Flow Province: the Delamerian heat flow sub-province (average surface heat flow 60 ± 9 mW m- 2); the Lachlan heat flow sub-province (average surface heat flow 74 ± 13 mW m- 2); and the Newer Volcanics heat flow sub-province (average surface heat flow 72 ± 16 mW m- 2) which includes extreme values that locally exceed 100 mW m- 2. Inversions of reduced heat flow and crustal differentiation find that the Delamerian sub-province has experienced significant crustal reworking compared to the Lachlan and Newer Volcanics sub-provinces. The latter has experienced volcanism within the last 8 Ma and the degree of variability observed in surface heat flow points (up to 8 mW m- 2 per kilometre laterally) cannot be replicated with steady-state thermal models through this sub-province. In the absence of a strong palaeoclimate signal, aquifer disturbances, or highly enriched granites, we suggest that this high variability arises from localised transient perturbations to the upper crust associated with recent intraplate volcanism. This is supported by a strong spatial correlation of high surface heat flow and known eruption points within the Newer Volcanics heat flow sub-province.

  18. Current knowledge on the crustal properties of Italy

    Directory of Open Access Journals (Sweden)

    C. Morelli

    1994-06-01

    Full Text Available The recent advances in experimental petrography together with the information derived from the super-deep drilling projects have provided additional constraints for the interpretation of refraction and reflection seismic data. These constraints can also be used in the interpretation of magnetic and gravity data to resolve nonuniqueness. In this study, we re-interpret the magnetic and gravity data of the Italian peninsula and neighbouring areas. In view of the constraints mentioned above, it is now possible to find an agreement between the seismic and gravity models of the Central Alps. By taking into account the overall crustal thickness, we have recognized the existence of three types of Moho: 1 European which extends to the north and west of the peninsula and in the Corsican-Sardinian block. Its margin was the foreland in the Alpine Orogeny and it was the ramp on which European and Adriatic mantle and crustal slices were overthrusted. This additional load caused bending and deepening and the Moho which now lies beneath the Adriatic plate reaching a maximum depth of approximately 75 km. 2 Adriatic (or African which lies beneath the Po plain, the Apennines and the Adriatic Sea. The average depth of the Moho is about 30-35 km below the Po plain and the Adriatic Sea and it increases toward the Alps and the Tyrrhenian Sea (acting as foreland along this margin. The maximum depth (50 km is reached in Calabria. 3 Pery-Tyrrhenian. This is an oceanic or thinned continental crust type of Moho. It borders the oceanic Moho of the Tyrrhenian Sea and it acquires a transitional character in the Ligurian and Provençal basins (<15 km thickness while further thickening occurs toward the East where the Adriatic plate is overthrusted. In addition, the interpretation of the heat flow data appears to confirm the origin of this Moho and its geodynamic allocation.

  19. Crustal block movements from Holocene shorelines: Rhodes Island (Greece)

    Science.gov (United States)

    Pirazzoli, P. A.; Montaggioni, L. F.; Saliège, J. F.; Segonzac, G.; Thommeret, Y.; Vergnaud-Grazzini, C.

    1989-12-01

    Signs of up to eight stepped Holocene shorelines, which have been reported in a previous study on the east coast of Rhodes Island, have been reinvestigated in detail on the basis of a new geomorphological survey, identification and petrological analysis of many new samples of exposed marine organic crusts and over 30 radiocarbon datings. Confirmation was obtained of the view that the island can be charactered by considering small crustal blocks up to a dozen kilometres long with each block being affected by a specific tectonic history, and a general trend towards an uplift increasing from south to north. Two successive phases of submergence-emergence have been revealed by petrogenetic sequences in many samples, which give evidence of the occurrence of positive and negative vertical movements. This implies possible rejuvenation effects of the later submergence phase on the apparent age of pre-existing algal crusts, and those have been taken into account and estimated. The most likely sequence of vertical crustal movements to have occurred has been specified for each block and a time range has been ascribed to each former shoreline. Independent up and down movements, increasing in amplitude from south to north, appear in most blocks. There is a recurrent periodicity varying from a few hundred to one or at most two thousand years. The largest vertical displacement observed during the late Holocene—a sudden uplift movement of about 3.8 m in the northernmost part of the island—is likely to be linked with the earthquake which destroyed the Colossus in 222 B.C.

  20. Effect of Varying Crustal Thickness on CHAMP Geopotential Data

    Science.gov (United States)

    Taylor, P. T.; Kis, K. I.; vonFrese, R. R. B.; Korhonen, J. V.; Wittmann, G.; Kim, H. R.; Potts, L. V.

    2003-01-01

    To determine the effect of crustal thickness variation on satellite-altitude geopotential anomalies we compared two regions of Europe with vastly different values, Central/Southern Finland and the Pannonian Basin. Crustal thickness exceeds 62 km in Finland and is less than 26 km in the Pannonian Basin. Heat-flow maps indicate that the thinner and more active crust of the Pannonian Basin has a value nearly three times that of the Finnish Svecofennian Province. Ground based gravity mapping in Hungary shows that the free-air gravity anomalies across the Pannonian Basin are near 0 to +20 mGal with shorter wavelength anomalies from +40 to less than +60 mGal and some 0 to greater than -20 mGal. Larger anomalies are detected in the mountainous areas. The minor value anomalies can indicate the isostatic equilibrium for Hungary (the central part of the Pannonian Basin). Gravity data over Finland are complicated by de-glaciation. CHAMP gravity data (400 km) indicates a west-east positive gradient of greater than 4 mGal across Central/Southern Finland and an ovoid positive anomaly (approximately 4 mGal) quasi-coincidental with the magnetic anomaly traversing the Pannonian Basin. CHAMP magnetic data (425 km) reveal elongated semicircular negative anomalies for both regions with South-Central Finland having larger amplitude (less than -6 nT) than that over the Pannonian Basin, Hungary (less than -5 nT). In both regions subducted oceanic lithosphere has been proposed as the anomalous body.

  1. Preliminary report on seismic-reflection studies of crustal structure in the western, central, and southern United States

    Science.gov (United States)

    Roller, J.C.; Strozier, O.P.; Jackson, W.H.; Healy, J.H.

    1963-01-01

    During 1963 the U.S. Geological Survey, with the assistance of United ElectroDynamics, Inc., recorded five separate reversed seismic profiles. In addition to these profiles, the U.S. Geological Survey participated in a seismic-calibration program for the DRIBBLE experiment at Tatum Dome, Mississippi, a 20,000-pound shot near Dexter, Missouri, and in a cooperative seismic experiment in the Lake Superior region. This work is a continuation of the program started in 1961; however, the emphasis has shifted from a detailed study of the earth's crust in the western United States to a study of crustal structure in various geologic environments including the Wyoming thrust belt, Colorado Plateau, Central Lowlands, the Gulf Coastal Plain, and the southern part of the Canadian Shield. The U.S. Geological Survey has now completed reversed seismic-refraction profiles in nine different geologic provinces. These data present a promising indication that it may be possible to predict the crustal structure in unexplored areas by considering the regional geologic and physiographic environment. The following Pn velocities have been determined: 8.2 km/sec in the Wyoming thrust belt, 7.9 km/sec in the Colorado Plateau, 8.1 km/sec in the Central Lowlands, and about 8.2 km/sec in the Gulf Coastal Plain. The data from the Lake Superior region have not yet been interpreted.

  2. Crustal Structure Beneath the Tibetan Plateau Using Receiver Functions and Surface Wave Dispersion Observations

    Science.gov (United States)

    Diehl, T.; Ammon, C. J.; Mejia, J.

    2002-12-01

    Despite substantial effort, some uncertainty in the bulk crustal geology beneath the Tibetan Plateau remains. Recent experiments have provided a wealth of seismic data for investigating structures within the Tibetan lithosphere. We investigate the subsurface Tibetan geology using receiver functions from the 1991-1992 Passive Source and the 1997-1999 INDEPTH III experiments. We have completed joint inversions of surface-wave dispersion and select receiver functions for the older data and plan to explore and invert receiver functions from select stations from the INDEPTH III experiment. The combination of receiver functions with surface-wave dispersion does much to improve P- and S-velocity structure resolution, but modeling is most appropriate for relatively simple structures. We begin our analyses with the depth-velocity stacking estimation of Zhu and Kanamori [2000] where we attempt to extract thickness, P-velocity, and Vp/Vs ratios compatible with the move-out of the Ps conversion and multiples from velocity contrasts within the lithosphere. Again, the main limitation of the technique is the assumption of a simple structure to insure consistency with a set of straightforward travel-time equations used to compute arrival-time move-out (as a function of incident-wave ray parameter). Poisson's ratio values from the 1991-1992 deployment were difficult to extract because of complex structure. The station with simplest response, WNDO, suggests a ratio of 0.28 beneath the north-central Plateau, which is slightly above average for continental crust. These results are lower than some earlier values which suggested that the lower crust beneath central and northern Tibet may contain substantial partial melt. The joint inversion of the simplest available receiver functions, and global long-period and local short-period surface-wave dispersion observations suggests that the crustal thickness for the northern Plateau ranges from 60-70 km (stations ERDO, BUDO, TUNL). Thickness

  3. Toward a robust workflow for deep crustal imaging by FWI of OBS data: The eastern Nankai Trough revisited

    Science.gov (United States)

    Górszczyk, Andrzej; Operto, Stéphane; Malinowski, Michał

    2017-06-01

    Crustal-scale imaging by the full-waveform inversion (FWI) of long-offset seismic data is inherently difficult because the large number of wavelengths propagating through the crust makes the inversion prone to cycle skipping. Therefore, efficient crustal-scale FWI requires an accurate starting model and a stable workflow minimizing the nonlinearity of the inversion. Here we attempt to reprocess a challenging 2-D ocean-bottom seismometer (OBS) data set from the eastern Nankai Trough. The starting model is built by first-arrival traveltime tomography (FAT), which is FWI assisted for tracking cycle skipping. We iteratively refine the picked traveltimes and then reiterate the FAT until the traveltime residuals remain below the cycle-skipping limit. Subsequently, we apply Laplace-Fourier FWI, in which progressive relaxation of time damping is nested within frequency continuation to hierarchically inject more data into the inversion. These two multiscale levels are complemented by a layer-stripping approach implemented through offset continuation. The reliability of the FWI velocity model is assessed by means of source wavelet estimation, synthetic seismogram modeling, ray tracing modeling, dynamic warping, and checkerboard tests. Although the viscoacoustic approximation is used for wave modeling, the synthetic seismograms reproduce most of the complexity of the data with a high traveltime accuracy. The revised FWI scheme produces a high-resolution velocity model of the entire crust that can be jointly interpreted with migrated images derived from multichannel seismic data. This study opens a new perspective on the design of OBS crustal-scale experiments amenable to FWI; however, a further assessment of the optimal OBS spacing is required for reliable FWI.

  4. Crustal uplift of the Precambrian cratons due to metamorphism in crustal rocks under infiltration of mantle fluids

    Science.gov (United States)

    Artyushkov, Eugene; Chekhovich, Peter; Korikovsky, Sergey; Massonne, Hans-Joachim

    2017-04-01

    Precambrian cratons cover about 70% of the total area of the continents. During the last several million years cratonic areas underwent rapid uplift, from 100-200 m in East Europe to 1000-1500 m Southern Africa. Shortening of the Precambrian crust terminated half a billion years ago or earlier and this popular mechanism cannot be applied to its recent uplift. Large thickness of cratonic mantle lithosphere, 100-200 km in most regions, together with its low density precludes delamination of this layer and magmatic underplating as possible causes of recent uplift. It cannot be precluded that in some cratonic regions recent uplift occurred due to delamination of the lower part of mantle lithosphere with the density increased by metasomatism. Even a small uplift of ≥ 100-200 m would require delamination of a thick layer of mantle lithosphere. As a result a temperature drop of > 200 C would arise at the base of the lithosphere producing a shear wave velocities drop of > 2%. According to the seismic tomography data such a drop in VS is observed only in some regions with the Precambrian lithosphere, e.g., in Northeastern Africa. Spatial distribution of the Precambrian cratons is quite different from that predicted by the main models of dynamic topography in the mantle. Moreover, many uplifted blocks are bounded by steep slopes hundreds of meters to one kilometer high and only tens of kilometers wide. Such slopes could not have been formed by bending of thick cratonic lithosphere under the forces acting from below. Their recent formation indicates rock expansion within the crust at shallow depth comparable with the slope width. Rocks formed at the pressure P ˜ 0.5-1.0 GPa are widespread on the Precambrian cratons. This indicates that during their lifetime a layer of rocks ˜ 15-30 km thick has been removed from the crustal surface by denudation. As a result rocks which were initially located in the lower crust emerged to the middle or upper crust. Due to metamorphic

  5. Micro-scale finite element modeling of ultrasound propagation in aluminum trabecular bone-mimicking phantoms: A comparison between numerical simulation and experimental results.

    Science.gov (United States)

    Vafaeian, B; Le, L H; Tran, T N H T; El-Rich, M; El-Bialy, T; Adeeb, S

    2016-05-01

    The present study investigated the accuracy of micro-scale finite element modeling for simulating broadband ultrasound propagation in water-saturated trabecular bone-mimicking phantoms. To this end, five commercially manufactured aluminum foam samples as trabecular bone-mimicking phantoms were utilized for ultrasonic immersion through-transmission experiments. Based on micro-computed tomography images of the same physical samples, three-dimensional high-resolution computational samples were generated to be implemented in the micro-scale finite element models. The finite element models employed the standard Galerkin finite element method (FEM) in time domain to simulate the ultrasonic experiments. The numerical simulations did not include energy dissipative mechanisms of ultrasonic attenuation; however, they expectedly simulated reflection, refraction, scattering, and wave mode conversion. The accuracy of the finite element simulations were evaluated by comparing the simulated ultrasonic attenuation and velocity with the experimental data. The maximum and the average relative errors between the experimental and simulated attenuation coefficients in the frequency range of 0.6-1.4 MHz were 17% and 6% respectively. Moreover, the simulations closely predicted the time-of-flight based velocities and the phase velocities of ultrasound with maximum relative errors of 20 m/s and 11 m/s respectively. The results of this study strongly suggest that micro-scale finite element modeling can effectively simulate broadband ultrasound propagation in water-saturated trabecular bone-mimicking structures. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Upper Crustal Structure of Santorini Volcano from Seismic Tomography using the PROTEUS dataset

    Science.gov (United States)

    Heath, B.; Hooft, E. E. E.; Morgan, J. V.; Toomey, D. R.; Nomikou, P.; Papazachos, C. V.; Warner, M.

    2016-12-01

    We present initial travel time tomography results from the PROTEUS experiment (Plumbing Reservoirs Of The Earth Under Santorini), an experiment designed to seismically image magma reservoirs beneath Santorini Volcano (Greece). Few seismic imaging studies have been previously conducted on Santorini and none have investigated the deeper crustal magmatic system. The experiment presents a unique opportunity to seismically probe the plumbing system of a historically active arc volcano because of a relatively thin Aegean crust, permitting easier seismic access to the subvolcanic magmatic system, and because of the ability to use marine air gun sound sources for imaging purposes. The latter provides over 1 million unique station-shot pairs ( 14000 airgun shots, over 100 onshore and offshore seismometers) producing a nearly unparalleled seismic dataset for a continental volcano. Our preliminary travel-time tomography results use tens of thousands of travel-time picks and a 3-D ray tracer to invert for anisotropic velocity structure of the upper 5 km of Santorini Volcano and surrounding tectonic region. Our tomographic images provide new constraints on how differing stages of tectonism and volcanism have shaped the geologic structure of the Aegean Volcanic Arc; specifically, we utilize our seismic dataset as well as the unique bathymetric dataset collected during the PROTEUS experiment to study the relationship between seismic velocity, faulting, and volcanism. These results are the first of a multi-year effort to both seismically image Santorini Volcano and understand how our images compare to other geophysical/geochemical models of Santorini and other analogous volcanoes. This experiment represents an unique opportunity to tomographically investigate the magmatic plumbing of a geochemically and volcanologically well-studied volcano.

  7. Seismic Imaging across the Moroccan Atlas (SIMA): An effort to constrain the crustal thickness of the Atlas Mountains

    Science.gov (United States)

    Carbonell, R.; Ayarza, P.; Harnafi, M.; Teixell, A.; Kchikah, A.; Martí, D.; Palomeras, I.; Levander, A.; Gallart, J.; Arboleya, M.; Charroud, M.; Amrhar, M.

    2011-12-01

    The Atlas Mountains are a young intra-continental Cenozoic orogenic belt located at the southern edge of the diffuse plate boundary zone separating Africa and Europe. The Atlas features a high topography that locally exceeds 4000 m. However, geological and preliminary geophysical studies suggest that it has experienced less than 25% of shortening and moderate crustal thickening. These observations rise the question of the origin of the Atlas high elevation. Potential field geophysical studies and previous low-resolution refraction experiments report a maximum crustal thickness of ~40 km, suggesting that the range is out of isostatic equilibrium at a crustal level and that an asthenospheric upwelling is needed to support the mountain load. These models, however, lack the constraints that would provide the knowledge of the precise Moho depth. In order to fulfill this requirement and to constrain the seismic velocity structure of this mountain system, a 700 km long, seismic wide-angle reflection and refraction transect has been recently acquired by an international team. The north-south transect extends from the Sahara Desert south of Merzouga, to Ceuta at the Gibraltar arc, crossing the High and Middle Atlas and the Rif mountains. Seismic energy released at 6 shot points generated by the detonation of 1 TN of explosives was recorded by ~ 900 Reftek-125a seismic recorders from the IRIS-PASSCAL pool. Seismic stations were deployed with an average spacing of 650-750 m. The 6 shot points were located within the southern part of the transect with a shot spacing of ~60-70 km. Preliminary analysis of data shows an uneven distribution of the energy, providing a poor signal/ratio relation at longest offsets, thus hindering the identification of the deepest phases. However, crustal phases (Pg and PiP) and mantle reflected/refracted phases (PmP and Pn) are present in most of the shot gathers. Preliminary modelling of these phases leads to an estimation of the changes in the

  8. Crustal structure at the western end of the North Anatolian Fault Zone from deep seismic sounding

    Directory of Open Access Journals (Sweden)

    B. Baier

    2001-06-01

    Full Text Available The first deep seismic sounding experiment in Northwestern Anatolia was carried out in October 1991 as part of the "German - Turkish Project on Earthquake Prediction Research" in the Mudurnu area of the North Anatolian Fault Zone. The experiment was a joint enterprise by the Institute of Meteorology and Geophysics of Frankfurt University, the Earthquake Research Institute (ERI in Ankara, and the Turkish Oil Company (TPAO. Two orthogonal profiles, each 120 km in length with a crossing point near Akyazi, were covered in succession by 30 short period tape recording seismograph stations with 2 km station spacing. 12 shots, with charge sizes between 100 and 250 kg, were fired and 342 seismograms out of 360 were used for evaluation. By coincidence an M b = 4.5 earthquake located below Imroz Island was also recorded and provided additional information on Moho and the sub-Moho velocity. A ray tracing method orginally developed by Weber (1986 was used for travel time inversion. From a compilation of all data two generalized crustal models were derived, one with velocity gradients within the layers and one with constant layer velocities. The latter consists of a sediment cover of about 2 km with V p » 3.6 km/s, an upper crystalline crust down to 13 km with V p » 5.9 km/s, a middle crust down to 25 km depth with V p » 6.5 km/s, a lower crust down to 39 km Moho depth with V p » 7.0 km/s and V p » 8.05 km/s below the Moho. The structure of the individual profiles differs slightly. The thickest sediment cover is reached in the Izmit-Sapanca-trough and in the Akyazi basin. Of particular interest is a step of about 4 km in the lower crust near Lake Sapanca and probably an even larger one in the Moho (derived from the Imroz earthquake data. After the catastrophic earthquake of Izmit on 17 August 1999 this significant heterogeneity in crustal structure appears in a new light with regard to the possible cause of the Izmit earthquake. Heterogeneities in

  9. A Rare Case of Arteriovenous Hemangioma Clinically Mimicking Pigmented Nevus

    Directory of Open Access Journals (Sweden)

    Sri Lestari

    2015-05-01

    Full Text Available Abstrak   Arteriovenous hemangioma (AH adalah lesi jinak pembuluh darah kulit yang jarang, biasanya muncul pada kulit wajah berupa lesi tunggal, meninggi, papul merah, atau keunguan; kadang-kadang papul coklat. Dilaporkan satu kasus AH dengan gambaran klinis menyerupai nevus pada pasien perempuan yang berusia 19 tahun. Ini adalahkasus pertama di Bagian Ilmu Kesehatan Kulit dan Kelamin RS. Dr. M. Djamil Padang. Pasien datang dengan keluhan bintik hitam di lengan kanan bawah sejak satu bulan lalu. Pada pemeriksaan fisik, terdapat papul hitam soliter, dengan ukuran 0,3 x 0, 4 mm, bentuk bulat, skuama halus,  berbatas tegas, pinggir reguler dengan permukaan tidak rata.Berdasarkan pemeriksaan histopatologi, lesi terdiri dari pembuluh darah yang berdinding tebal dan berdinding tipis yang sangat melebar, penuh dengan eritrosit dan dilapisi oleh selapis endotel yang sesuai untuk AH. Arteriovenous hemangioma adalah tumor yang dijumpai pada usia pertengahan hingga dewasa lanjut dengan puncak insiden pada dekade keempat dan kelima kehidupan. Pada kasus ini, umur pasien tergolong dewasa muda dengan gambaran klinis lesi menyerupai nevus pigmentosus. Kata kunci: arteriovenous hemangioma, kasus jarang, nevus pigmentosus Abstract Arteriovenous hemangioma (AH is a rare benign vascular skin lesion, which typically appears in the skin of the face and extremities and  most commonly occurring on the head and neck region with appearances as single, raised, red, or violaceous papules; sometime tan papule. A case of AH clinically mimicking pigmented nevus in 19year-old womanwas reported. This is the first case in Dermatology Department of Dr.M. Djamil Padang Hospital. She complained about a black pimple on the right lower arm since one month. Physical examination: there is a solitare black papule, with 0,3x0,4 mm, round shape, fine scales, well defined, regular border with irreguler surface.Histopathology findings: the lesions consist of thicked-walled and very

  10. Crustal and deep seismicity in Italy (30 years after

    Directory of Open Access Journals (Sweden)

    G. Selvaggi

    1997-06-01

    Full Text Available The first modern studies of seismicity in Italy date back to the late 60's and early 70's. Although with a sparse seismic network available and only a few telemetered short-period stations, significant studies were carried out that outlined the main features of Italian seismicity (see, e.g., Boschi et al., 1969. Among these studies, one of the most important achievements was the reconnaissance of a Wadati-Benioff zone in Southern Tyrrhenian, described for the first time in detail in the papers of Caputo et al.(1970, 1973. Today, after three decades of more and more detailed seismological monitoring of the Italian region and tens of thousands earthquakes located since then, the knowledge of the earthquake generation processes in our country is much improved, although some of the conclusions reached in these early papers still hold. These improvements were made possible by the efforts of many institutions and seismologists who have been working hard to bring seismological research in Italy to standards of absolute quality, under the pivoting role of the Istituto Nazionale di Geofisica (ING. From the relocation of about 30000 crustal earthquakes and detailed studies on intermediate and deep shocks carried out in the last few years, we show that seismic release in peninsular Italy is only weakly related to the Africa-Eurasia convergence, but rather is best explained by the existence of two separate subduction/collision arcs (Northern Apennines and Southern Apennines-Calabria-Sicily. The width of the deforming belt running along peninsular Italy is 30 to 60 km, it is broader in the north than in the south, and the two arcs are separated by a region of more distributed deformation and stress rotations in the Central Apennines. Along the belt, the reconnaissance of regions of continuous and weak release of seismic energy, adjacent to fault areas which are currently «locked» (and therefore are the best candidates for future earthquakes is another

  11. The crystal's view of upper-crustal magma reservoirs

    Science.gov (United States)

    Cooper, K. M.; Kent, A. J.; Huber, C.; Stelten, M. E.; Rubin, A. E.; Schrecengost, K.

    2015-12-01

    Upper-crustal magma reservoirs are important sites of magma mixing, crustal refining, and magma storage. Crystals residing in these reservoirs have been shown to represent valuable archives of the chemical and physical evolution of reservoirs, and the time scales of this evolution. This presentation addresses the question of "What do crystals "see" and record about processes within the upper crust? And how is that view similar or different between plutonic and volcanic records?" Three general observations emerge from study of the ages of crystals, combined with crystal-scale geochemical data: 1) Patterns of isotopic and trace-element data over time in zircon crystals from a given magmatic system (e.g., Yellowstone, WY, and Taupo Volcanic Zone, New Zealand) can show systematic changes in the degree of heterogeneity, consistent with extraction of melts from a long-lived (up to 100s of kyr), heterogeneous crystal mush and in some cases continued crystallization and homogenization of the magma during a short period (eruption. 2) Thermal histories of magma storage derived from crystal records also show that the vast majority of time recorded by major phases was spent in storage as a crystal mush, perhaps at near-solidus conditions. 3) Comparison of ages of accessory phases in both plutonic blocks and host magmas that brought them to the surface do not show a consistent relationship between the two. In some cases, zircons from plutonic blocks have age spectra much older than zircon in the host magma. In other cases, host and plutonic block zircons have similar age spectra and chemical characteristics, suggesting a closer genetic connection between the two. These observations suggest that crystals in plutonic bodies, if examined at similar spatial and temporal scales to those in volcanic rocks, would show records that are highly heterogeneous in chemistry and age on the scale of a pluton or a lobe of a pluton, but that local regions of limited chemical and age variability

  12. Fluvial archives, a valuable record of vertical crustal deformation

    Science.gov (United States)

    Demoulin, A.; Mather, A.; Whittaker, A.

    2017-06-01

    The study of drainage network response to uplift is important not only for understanding river system dynamics and associated channel properties and fluvial landforms, but also for identifying the nature of crustal deformation and its history. In recent decades, geomorphic analysis of rivers has proved powerful in elucidating the tectonic evolution of actively uplifting and eroding orogens. Here, we review the main recent developments that have improved and expanded qualitative and quantitative information about vertical tectonic motions (the effects of horizontal deformation are not addressed). Channel long profiles have received considerable attention in the literature, and we briefly introduce basic aspects of the behaviour of bedrock rivers from field and numerical modelling perspectives, before describing the various metrics that have been proposed to identify the information on crustal deformation contained within their steady-state characteristics. Then, we review the literature dealing with the transient response of rivers to tectonic perturbation, through the production of knickpoints propagating through the drainage network. Inverse modelling of river profiles for uplift in time and space is also shown to be very effective in reconstructing regional tectonic histories. Finally, we present a synthetic morphometric approach for deducing the tectonic record of fluvial landscapes. As well as the erosional imprint of tectonic forcing, sedimentary deposits, such as fluvial terrace staircases, are also considered as a classical component of tectonic geomorphology. We show that these studies have recently benefited from rapid advances in dating techniques, allowing more reliable reconstruction of incision histories and estimation of incision rates. The combination of progress in the understanding of transient river profiles and larger, more rigorous data sets of terrace ages has led to improved understanding of river erosion and the implications for terrace

  13. A numerical model for dynamic crustal-scale fluid flow

    Science.gov (United States)

    Sachau, Till; Bons, Paul; Gomez-Rivas, Enrique; Koehn, Daniel

    2015-04-01

    Fluid flow in the crust is often envisaged and modeled as continuous, yet minimal flow, which occurs over large geological times. This is a suitable approximation for flow as long as it is solely controlled by the matrix permeability of rocks, which in turn is controlled by viscous compaction of the pore space. However, strong evidence (hydrothermal veins and ore deposits) exists that a significant part of fluid flow in the crust occurs strongly localized in both space and time, controlled by the opening and sealing of hydrofractures. We developed, tested and applied a novel computer code, which considers this dynamic behavior and couples it with steady, Darcian flow controlled by the matrix permeability. In this dual-porosity model, fractures open depending on the fluid pressure relative to the solid pressure. Fractures form when matrix permeability is insufficient to accommodate fluid flow resulting from compaction, decompression (Staude et al. 2009) or metamorphic dehydration reactions (Weisheit et al. 2013). Open fractures can close when the contained fluid either seeps into the matrix or escapes by fracture propagation: mobile hydrofractures (Bons, 2001). In the model, closing and sealing of fractures is controlled by a time-dependent viscous law, which is based on the effective stress and on either Newtonian or non-Newtonian viscosity. Our simulations indicate that the bulk of crustal fluid flow in the middle to lower upper crust is intermittent, highly self-organized, and occurs as mobile hydrofractures. This is due to the low matrix porosity and permeability, combined with a low matrix viscosity and, hence, fast sealing of fractures. Stable fracture networks, generated by fluid overpressure, are restricted to the uppermost crust. Semi-stable fracture networks can develop in an intermediate zone, if a critical overpressure is reached. Flow rates in mobile hydrofractures exceed those in the matrix porosity and fracture networks by orders of magnitude

  14. Crustal Velocity Model of the Altai-Sayan Region

    Science.gov (United States)

    Behrend, M. J.; Mackey, K. G.

    2016-12-01

    We have developed a crustal velocity model for the the region encompassed by the Altai-Sayan Seismic Network of South-Central Russia (45o-55o N. X 79o-98o E.). Geographically, the study area includes the Altai and Sayan Mountain Ranges, Western Mongolia, Eastern Kazakhstan, and Northwest China. To develop our model we used phase arrival data from approximately 175 larger earthquakes recorded by the Altai-Sayan Seismic Network between 1977 and 1981 and reported in the bulletin Materialy po Seismichnosti Sibiri. To develop our model, we divided the region into 1o N-S x 2o E-W cells. Events within each cell, plus a small surrounding area, were relocated multiple times using a grid-search routine, in effort to determine the best fitting Pg and Sg velocities. Pg and Sg phase arrivals are generally from the 100-1000 km range and represent secondary arriving phases. These arrivals are dominant in this region and we consider the time picks and phase identifications to be reliable. Velocities tested range from 5.650 to 6.350 km/s for Pg and from 3.310 to 3.710 km/s for Sg. The best fitting velocities for each cell were then assigned to the geographic coordinates of the cell's center point. The standard Jeffreys-Bullen model was used for Pn velocities. The best fitting Pg and Sg velocities are those that minimize the average event residuals in a cell. High residual arrivals were omitted from the location process. In our model, Pg velocities range from 5.975-6.325 km/s, while Sg velocities range from 3.510-3.630 km/s, though the higher velocity extremes are constrained by one event and are not statistically significant. The average Pg velocity of the study area was, 6.147 km/s, and average Sg, 3.576 km/s. Geologically, these velocities are associated with the Central Asiatic Foldbelt and are consistent with regional crustal velocities along the southern edge of the Siberian Craton to the East as determined by previous studies.

  15. Electrochemically controlled drug-mimicking protein release from iron-alginate thin-films associated with an electrode.

    Science.gov (United States)

    Jin, Zhiyuan; Güven, Güray; Bocharova, Vera; Halámek, Jan; Tokarev, Ihor; Minko, Sergiy; Melman, Artem; Mandler, Daniel; Katz, Evgeny

    2012-01-01

    Novel biocompatible hybrid-material composed of iron-ion-cross-linked alginate with embedded protein molecules has been designed for the signal-triggered drug release. Electrochemically controlled oxidation of Fe(2+) ions in the presence of soluble natural alginate polymer and drug-mimicking protein (bovine serum albumin, BSA) results in the formation of an alginate-based thin-film cross-linked by Fe(3+) ions at the electrode interface with the entrapped protein. The electrochemically generated composite thin-film was characterized by electrochemistry and atomic force microscopy (AFM). Preliminary experiments demonstrated that the electrochemically controlled deposition of the protein-containing thin-film can be performed at microscale using scanning electrochemical microscopy (SECM) as the deposition tool producing polymer-patterned spots potentially containing various entrapped drugs. Application of reductive potentials on the modified electrode produced Fe(2+) cations which do not keep complexation with alginate, thus resulting in the electrochemically triggered thin-film dissolution and the protein release. Different experimental parameters, such as the film-deposition time, concentrations of compounds and applied potentials, were varied in order to demonstrate that the electrodepositon and electrodissolution of the alginate composite film can be tuned to the optimum performance. A statistical modeling technique was applied to find optimal conditions for the formation of the composite thin-film for the maximal encapsulation and release of the drug-mimicking protein at the lowest possible potential. © 2011 American Chemical Society

  16. 3-D crustal P-wave velocity tomography of the Italian region using local and regional seismicity data

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    F. M. Mele

    1995-06-01

    Full Text Available A tomographic experiment was performed in the Italian region using local and regional arrivaI times of p and S seismological phases selected from the Italian National Bulletin in the time interval 1984-1991. We deter- mined a 3-D crustal P-wave velocity model using a simultaneous inversion method that iteratively re1ocates the hypocenters and computes the unknown model parameters. A fast two-point ray tracing algorithm was adopted to compute the ray paths and travel times of P", S", P g' Sg phases with good accuracy. Synthetic tests were performed using the "true" hypocenter and station distribution to rough1y evaluate the extension of the areas most densely spanned by the ray paths; the agreement between synthetic and computed models is more satisfactory at Moho depths than in the upper crust. The qua1ity of the model resulting from inversion of real data is examined by the ca1culation of the Spread Function (Toomey and Foulger, 1989. The 3-D crustal P-wave velocity mode1 of the Italian region shows remarkab1e trends at Moho depths: the areas east of the Apennines call for positive adjustments of the initial velocity va1ue, while the west region shows negative ad- justments. The correspondence among the main features of the velocity field, the map of Moho isobaths and the map of the gravity anoma1ies is also outlined.

  17. Crustal and lithospheric thinning beneath the seismogenic Kachchh rift zone, Gujarat (India): Its implications toward the generation of the 2001 Bhuj earthquake sequence

    Science.gov (United States)

    Mandal, Prantik

    2011-01-01

    A high-resolution passive seismic experiment in the Kachchh rift zone of the western India has produced an excellent dataset of several thousands teleseismic events. From this network, 500 good teleseismic events recorded at 14 mobile broadband sites are used to estimate receiver functions (for the 30-310° back-azimuth ranges), which show a positive phase at 4.5-6.1 s delay time and a strong negative phase at 8.0-11.0 s. These phases have been modeled by a velocity increase at Moho (i.e. 34-43 km) and a velocity decrease at 62-92 km depth. The estimation of crustal and lithospheric thicknesses using the inversion of stacked radial receiver functions led to the delineation of a marked thinning of 3-7 km in crustal thickness and 6-14 km in lithospheric thickness beneath the central rift zone relative to the surrounding un-rifted parts of the Kachchh rift zone. On an average, the Kachchh region is characterized by a thin lithosphere of 75.9 ± 5.9 km. The marked velocity decrease associated with the lithosphere-asthenoshere boundary (LAB), observed over an area of 120 km × 80 km, and the isotropic study of xenoliths from Kachchh provides evidence for local asthenospheric updoming with pockets of partial melts of CO 2 rich lherzolite beneath the Kachchh seismic zone that might have caused by rifting episode (at 88 Ma) and the associated Deccan thermal-plume interaction (at 65 Ma) episodes. Thus, the coincidence of the area of the major aftershock activity and the Moho as well as asthenospheric upwarping beneath the central Kachchh rift zone suggests that these pockets of CO 2-rich lherzolite partial melts could perhaps provide a high input of volatiles containing CO 2 into the lower crust, which might contribute significantly in the seismo-genesis of continued aftershock activity in the region. It is also inferred that large stresses in the denser and stronger lower crust (at 14-34 km depths) induced by ongoing Banni upliftment, crustal intrusive, marked lateral

  18. Enzyme-mimicking polymer brush-functionalized surface for combating biomaterial-associated infections

    Science.gov (United States)

    Jiang, Rujian; Xin, Zhirong; Xu, Shiai; Shi, Hengchong; Yang, Huawei; Song, Lingjie; Yan, Shunjie; Luan, Shifang; Yin, Jinghua; Khan, Ather Farooq; Li, Yonggang

    2017-11-01

    Biomaterial-associated infections critically compromise the functionality and performance of the medical devices, and pose a serious threat to human healthcare. Recently, natural DNase enzyme has been recognized as a potent material to prevent bacterial adhesion and biofilm formation. However, the vulnerability of DNase dramatically limits its long-term performance in antibacterial applications. In this work, DNase-mimicking polymer brushes were constructed to mimic the DNA-cleavage activity as well as the macromolecular scaffold of the natural DNase. The bacteria repellent efficacy of DNase-mimicking polymer brush-functionalized surface was comparable to that of the DNase-functionalized surface. More importantly, due to their inherent stability, DNase-mimicking polymer brushes presented the much better performance in inhibiting bacterial biofilm development for prolonged periods of time, as compared to the natural DNase. The as-developed DNase-mimicking polymer brush-functionalized surface presents a promising approach to combat biomaterial-associated infections.

  19. Multifocal Skeletal Tuberculosis Mimicking Metastasis Involving the Sternum, Lumbar Vertebra, and Sacrum

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Ho; Cho, Soon Gu; Kim, Kwang Ho; Kim, Yeo Ju; Hyun, In Young; Lee, Kyung Hee [Inha University Hospital, Incheon (Korea, Republic of)

    2010-02-15

    The incidence of multifocal skeletal tuberculosis is very rare and its diagnosis, very difficult because of vague somatic symptoms and non-specific physical and radiologic findings. We report a case of multifocal skeletal tuberculosis mimicking metastasis

  20. Acute Fulminant Uremic Neuropathy Following Coronary Angiography Mimicking Guillain?Barre Syndrome

    OpenAIRE

    Priti, Kumari; Ranwa, Bhanwar

    2017-01-01

    A 55-year-old diabetic woman suffered a posterior wall ST-elevation myocardial infarction. She developed contrast-induced nephropathy following coronary angiography. Acute fulminant uremic neuropathy was precipitated which initially mimicked Guillan?Barre Syndrome, hence reported.

  1. Acute Fulminant Uremic Neuropathy Following Coronary Angiography Mimicking Guillain-Barre Syndrome.

    Science.gov (United States)

    Priti, Kumari; Ranwa, Bhanwar

    2017-01-01

    A 55-year-old diabetic woman suffered a posterior wall ST-elevation myocardial infarction. She developed contrast-induced nephropathy following coronary angiography. Acute fulminant uremic neuropathy was precipitated which initially mimicked Guillan-Barre Syndrome, hence reported.

  2. Constraints on the Venusian crustal thickness variations in the isostatic stagnant lid approximation

    National Research Council Canada - National Science Library

    Orth, C. P; Solomatov, V. S

    2012-01-01

    .... Here we assume that the remaining discrepancy between the observed and model geoid is due to crustal thickness variations and that the crust, the lithosphere and the mantle are in a state of double...

  3. The influence of crustal radioactivity on mantle convection and lithospheric thickness on Mars

    National Research Council Canada - National Science Library

    Kiefer, Walter S

    2016-01-01

    ... . In an important new paper, Plesa et al. (2016, doi: 10.1002/2016JE005126 ) have assessed how these variations in crustal thickness and heat flow affect the spatial pattern of convection in the Martian mantle...

  4. Displaced terranes and crustal evolution of the Levant and the eastern Mediterranean

    Science.gov (United States)

    Ben-Avraham, Zvi; Ginzburg, Avihu

    1990-08-01

    Geophysical data from the Levant and the eastern Mediterranean suggest that this area can be divided into distinct crustal units of different origins. For example, a marked difference in crustal structure and structural style exists in the Levant between Samaria and Judea, south of the Carmel structure, and the Galilee and Lebanon, north of it. On the other hand, several microcontinental fragments such as Cyprus, and the Eratosthenes and Anaximander Seamounts are embedded within the oceanic crust of the eastern Mediterranean. The present location of these units has resulted from complex tectonic processes which were active during the mid Paleozoic-Mesozoic evolution of this area. During this period several crustal units were accreted to the northern margin of Africa while others were detached away from it. The crustal evolution of the eastern Mediterranean and the Levant is intimately linked with the closure of the Paleo-Tethys, the formation of the Neo-Tethys, and its subsequent closure.

  5. Particle-in-Cell Simulations of Plasma Interaction with Lunar Crustal Magnetic Anomalies

    Science.gov (United States)

    Poppe, A. R.; Halekas, J. S.; Delory, G. T.; Farrell, W. M.

    2012-03-01

    We present results from a kinetic plasma simulation on the interaction of ambient plasma with lunar crustal magnetic anomalies. We discuss implications of this work for physical phenomena at the Moon, such as lunar swirls and proton implantation.

  6. Orbital compressed air and petroleum injury mimicking necrotizing fasciitis.

    Science.gov (United States)

    Mellington, Faye E; Bacon, Annette S; Abu-Bakra, Mohammed A J; Martinez-Devesa, Pablo; Norris, Jonathan H

    2014-09-01

    Orbital injury secondary to petroleum-based products is rare. We report the first case, to our knowledge, of a combined compressed air and chemical orbital injury, which mimicked necrotizing fasciitis. A 58-year-old man was repairing his motorcycle engine when a piston inadvertently fired, discharging compressed air and petroleum-based carburetor cleaner into his left eye. He developed surgical emphysema, skin necrosis, and a chemical cellulitis, causing an orbital compartment syndrome. He was treated initially with antibiotics and subsequently with intravenous steroid and orbital decompression surgery. There was almost complete recovery by 4 weeks postsurgery. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Petroleum-based products can cause severe skin irritation and necrosis. Compressed air injury can cause surgical emphysema. When these two mechanisms of injury are combined, the resulting orbitopathy and skin necrosis can mimic necrotizing fasciitis and cause diagnostic confusion. A favorable outcome is achievable with aggressive timely management. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Visual Loss from Choroidal Melanoma Mimicking Neurological Syndromes

    Directory of Open Access Journals (Sweden)

    Karim Hammamji

    2017-03-01

    Full Text Available Melanoma of the eye is rare, but can mimic a range of disorders. This report highlights 2 cases of choroidal melanoma with vision loss mimicking neurological diagnoses. The first patient is a 41-year-old white male with a known history of multiple sclerosis and a previous episode of optic neuritis in the right eye, who presented with a 6-month history of decreased vision in the same eye, and occasional photopsiae. He was treated with 2 courses of oral steroids for presumed recurrent optic neuritis. After a temporary improvement in his symptoms, his vision worsened, following which he had a head MRI, which revealed a solid intraocular mass. He was subsequently diagnosed with a choroidal melanoma for which he was treated successfully with ruthenium-106 plaque brachytherapy. The second patient is a 57-year-old female, who presented with a progressive cerebellar syndrome under investigation by the neurology service, as well as decreased vision in the right eye. Her visual acuity gradually deteriorated and her neurological assessment, which included a PET-CT, revealed uptake in the right eye. The diagnosis of a choroidal melanoma was made, and following conservative treatment with proton beam radiotherapy, she had an enucleation of the eye. Intraocular tumours can masquerade as many different entities. Unexplained unilateral visual loss, especially if it is atypical for a neurological syndrome, should prompt dilated fundoscopy and referral to an ophthalmologist.

  8. Hepatic glycogenosis in type 1 diabetes mellitus mimicking Mauriac syndrome.

    Science.gov (United States)

    Jung, In Ah; Cho, Won Kyoung; Jeon, Yeon Jin; Kim, Shin Hee; Cho, Kyoung Soon; Park, So Hyun; Jung, Min Ho; Suh, Byung-Kyu

    2015-06-01

    Hepatic glycogenosis in type 1 diabetes mellitus (DM) can be caused by poor glycemic control due to insulin deficiency, excessive insulin treatment for diabetic ketoacidosis, or excessive glucose administration to control hypoglycemia. Mauriac syndrome, which is characterized by hepatomegaly due to hepatic glycogenosis, growth retardation, delayed puberty, and Cushingoid features, is a rare diabetic complication. We report a case of hepatic glycogenosis mimicking Mauriac syndrome. A 14-year-old girl with poorly controlled type 1 DM was admitted to The Catholic University of Korea, Seoul St. Mary's Hospital for abdominal pain and distension. Physical examination revealed hepatomegaly and a Cushingoid face. The growth rate of the patient had decreased, and she had not yet experienced menarche. Laboratory findings revealed elevated liver enzyme levels. A liver biopsy confirmed hepatic glycogenosis. Continuous glucose monitoring showed hyperglycemia after meals and frequent hypoglycemia before meals. To control hyperglycemia, we increased insulin dosage by using an insulin pump. In addition, we prescribed uncooked cornstarch to prevent hypoglycemia. After strict blood glucose control, the patient's liver functions and size normalized. The patient subsequently underwent menarche. Hepatic glycogenosis is a complication of type 1 DM that is reversible with appropriate glycemic control.

  9. Duodenal White Spots Mimicking Intestinal Candidiasis: Report of Case

    Directory of Open Access Journals (Sweden)

    Ozgur Turk

    2015-12-01

    Full Text Available Duodenal white spots are mentioned in these nonspecific lesions until recently. Although there is not enough studies about duedonal white spots yet; these lesions described in a separate syndrome. Here now we reported a case that we diagnosed multiple Duodenal white spots mimicking intestinal candidiasis. Clinical manifestation and endoscopic appearance of lesions gave rise to thought intestinal candidiasis histopathological examination revealed us several duodenitis. There was no evidence of fungal infection in PAS staining. Early after endoscopy patient took treatment of Lansoprozole at the 30 mg dose and bismuth salicylate. Patients compliant declined and control endoscopy exposed white duodenal spots cleared away three months later. Duodenal white spots are becoming to be designated as a separate disease even a syndrome. Etiology of duodenal white spots must be determined carefully during endoscopy. Sometimes it is difficult to make the correct diagnosis by appearance of lesion; in such cases histopathological examination can be useful both differential diagnosis of disease and determination of etiological factor. [J Contemp Med 2015; 5(4.000: 249-252

  10. Follicular thyroid carcinoma mimicking meningioma: A case report

    Directory of Open Access Journals (Sweden)

    Krishnalatha Buandasan

    2012-02-01

    Full Text Available Follicular thyroid carcinoma (FTC is a well-differentiated tumor which resembles the normal microscopic pattern of the thyroid. Although intracranial metastasis to the brain is frequent in adults, metastasis from FTC is very rare. Dural metastases mimicking meningioma have been documented in the literature now and then. However, cases arising from a FTC are again very rare. We report the case of a middle-aged lady who presented with progressive, painless left eye proptosis. She was noted to have a non-axial proptosis with dystopia, compressive optic neuropathy and exposure keratitis. She also had a painless swelling over the occipital region. She was initially misdiagnosed to have multiple foci of meningioma based on magnetic resonance imaging findings. Subsequent histopathological examination revealed presence of FTC. She was euthyroid but was found to have multiple small thyroid nodules by ultrasonography. Hence, the definite diagnosis of all dural masses must be histological wherever possible and thyroid carcinoma should be considered as a potential primary tumour in such presentations.

  11. A case of relapsing polychondritis mimicking Ludwig’s angina

    Directory of Open Access Journals (Sweden)

    Adnan Agha

    2009-09-01

    Full Text Available Relapsing polychondritis (RP is a severe progressive inflammatory condition involving cartilaginous structures and caused by an autoimmune process, for which there is no confirmatory serological biomarker and which still is diagnosed on a mainly clinical basis. RP has been associated with many diseases like Sweet’s syndrome, Behcet’s disease, rheumatoid arthritis, and other autoimmune disorders. We attempt to describe here a unique case of a 38-year-old female with a high-grade fever, sore throat, difficulty in swallowing, hoarseness of the voice, and found to have signs of tongue swelling and inflammation of the oral cavity that mimicked Ludwig’s angina, necessitating antibiotic use. On careful re-evaluation the patient was diagnosed to have relapsing polychondritis based on auricular and respiratory tract chondritis and response to steroids. The purpose of this report is to emphasize the fact that careful clinical assessment is needed to diagnose RP, which may be misdiagnosed as Ludwig’s angina.

  12. Idiopathic Transverse Myelitis Mimicking an Intramedullary Spinal Cord Tumor

    Directory of Open Access Journals (Sweden)

    Andrew A. Fanous

    2016-01-01

    Full Text Available The differential diagnoses for spinal cord lesions include spinal tumors and inflammatory processes. The distinction between these pathologies can be difficult if solely based on imaging. We report for the first time to our knowledge a case of idiopathic transverse myelitis (ITM mimicking a discrete cervical spinal lesion in a 66-year-old man who presented with gait instability and neck pain. The patient’s symptoms failed to resolve after an initial course of steroid therapy. Surgical biopsy confirmed the diagnosis of ITM. Subsequent treatment with dexamethasone resulted in complete resolution of the symptoms as well as the intramedullary enhancement. ITM is most common in the cervical and thoracic spine, spanning 3-4 spinal segments. It usually occupies more than 50% of the cross-sectional area of the spinal cord and tends to be central, uniform, and symmetric. It exhibits patchy and peripheral contrast enhancement. These criteria are useful guidelines that help distinguish ITM from neoplastic spinal lesions. A decision to perform biopsy must take into consideration the patient’s clinical symptoms, the rate of progression of neurological deficits, and the imaging characteristics of the lesion. Surgical biopsy for questionable lesions should be reserved for patients with progressive neurological deficits refractory to empirical medical therapy.

  13. Strongyloides Colitis as a Harmful Mimicker of Inflammatory Bowel Disease

    Directory of Open Access Journals (Sweden)

    Julio Poveda

    2017-01-01

    Full Text Available Autoinfection caused by Strongyloides stercoralis frequently becomes a life-long disease unless it is effectively treated. There is overlapping histomorphology between Strongyloides colitis and inflammatory bowel disease; a low index of suspicion can lead to misdiagnosis and fatal consequences. We present a case of Strongyloides colitis mimicking the clinical and pathologic features of inflammatory bowel disease. A 64-year-old female presented to the emergency department with a four-day history of abdominal pain, diarrhea, and hematochezia. Colonoscopy revealed diffuse inflammation suggestive of inflammatory bowel disease, which led to initiation of 5-aminosalicylic acid and intravenous methylprednisolone. Biopsies of the colon revealed increased lymphoplasmacytic infiltrate of the lamina propria with eosinophilic microabscesses and presence of larvae, consistent with Strongyloides stercoralis. Immunosuppressive medication was halted. The patient ultimately died a few days later. This case emphasizes the importance of identifying the overlapping clinical and pathologic features of Strongyloides colitis and inflammatory bowel disease. A high index of suspicion and recognition of particular histological findings, including eosinophilic microabscesses, aid in the correct diagnosis. Definitive diagnosis is crucial as each disease carries distinct therapeutic implications and outcome.

  14. Cholangiocarcinoma and its mimickers in primary sclerosing cholangitis.

    Science.gov (United States)

    Lee, Jonghun John; Schindera, Sebastian T; Jang, Hyun-Jung; Fung, Scott; Kim, Tae Kyoung

    2017-12-01

    Cholangiocarcinoma (CCA) is the most common malignancy in primary sclerosing cholangitis (PSC). Approximately half of CCA are diagnosed within two years of initial diagnosis and often have a poor prognosis because of advanced tumor stage at the time of diagnosis. Thus, rigorous initial imaging evaluation for detecting CCA is important. CCA in PSC usually manifests as intrahepatic mass-forming or perihilar periductal-infiltrating type. Imaging diagnosis is often challenging due to pre-existing biliary strictures and heterogeneous liver. Multimodality imaging approach and careful comparison with prior images are often helpful in detecting small CCA. Ultrasound is widely used as an initial test, but has a limited ability to detect small tumors in the heterogeneous liver with PSC. MRI combined with MRCP is excellent to demonstrate focal biliary abnormalities as well as subtle liver masses. Contrast-enhanced ultrasound is useful to demonstrate CCA by demonstrating rapid and marked washout. In addition, there are other disease entities that mimic CCA including hepatocellular carcinoma, confluent hepatic fibrosis, IgG4-related sclerosing cholangitis, inflammatory mass, and focal fat deposition. In this pictorial essay, imaging findings of CCA in PSC is described and discuss the challenges in imaging surveillance for CCA in the patients with PSC. Imaging findings of the mimickers of CCA in PSC and their differentiating features are also discussed.

  15. Tophaceous gout of the lumbar spine mimicking a spinal meningioma.

    Science.gov (United States)

    Ribeiro da Cunha, Pedro; Peliz, António Judice; Barbosa, Marcos

    2016-11-05

    Although gout is a common metabolic disorder, it usually affects distal joints of the appendicular skeleton. Axial spine involvement is rare, with only 131 cases reported in the literature. The authors report a rare case of lumbar spinal gout mimicking a spinal meningioma. A 77-year-old man with a history of gout presented with chronic low back pain and progressive paraparesis. Imaging revealed a lumbar spine compressive mass lesion with a dural tail signal. The differential diagnosis was thought to be straightforward favoring a spinal meningioma. Tophaceous gout was never considered. The presence of a dural tail associated with the lesion is an interesting detail of this case, that strongly misguided it and to the best of our knowledge it is the first one reported in the literature. The patient underwent surgery and intra-operative findings were surprisingly different from those expected, revealing a chalky white mass lesion firmly adherent and compressing the dural sac. It was completely excised, leaving the dura intact. Histopathology confirmed the diagnosis of tophaceous gout. The patient was sent to physical therapy and had a complete remission of pain and neurological deficit, regaining his walking capacity. Although spinal gout is rare, it should be considered in the differential diagnosis for patients presenting with symptoms of spinal stenosis, a suspicion of neoplastic lesion of the spine, and a previous history of gout. Early diagnosis can ensure proper and timely medical management, perhaps avoiding neurological compromise and the need for surgery.

  16. Extramedullary Plasmacytoma Mimicking Pancreatic Cancer: An Unusual Presentation.

    Science.gov (United States)

    Sciancalepore, Daniela; Musci, Sergio; Fracella, Maria Rosaria; D'Alesio, Grazia; Sportelli, Azzurra; Ingravallo, Giuseppe; Vacca, Angelo; Ria, Roberto

    2016-01-01

    Multiple myeloma is a plasma cell tumor that homes to and expands in the bone marrow and that, despite the new available drugs, remains incurable. Extramedullary plasmacytoma is a not frequent manifestation during the natural history of multiple myeloma and is frequently associated with plasma cell bone marrow infiltration. The most common locations for an EMP include the gastrointestinal tract, pleura, testis, skin, peritoneum, liver, endocrine glands, and lymph nodes. Primary involvement of the gallbladder fossa is exceedingly rare. In this report, we describe a patient with multiple myeloma who achieved a clinical and serological remission after autologous transplant but progressed rapidly at extramedullary site mimicking a second cancer (i.e., pancreatic or biliary cancer). In this case, the extramedullary localization was refractory to standard therapy, differently from bone marrow localization, but responded to lymphoma-like therapy. In this patient (i) the particular site of developing plasmacytoma is the gallbladder fossa, (ii) the timing of onset of this neoplasm is immediately after autologous transplant, and (iii) its disjunction from primary myeloma is that it appears in clinical and serological remission phase which may be confounding during the diagnostic approach simulating a different tumor (solid tumor).

  17. Germinoma Mimicking Tumefactive Demyelinating Disease in Pediatric Patients.

    Science.gov (United States)

    Akiyama, Yukinori; Suzuki, Hime; Mikuni, Nobuhiro

    2016-01-01

    Cases of intracranial germinoma with granulomatous reaction are rare, so a pathological diagnosis of this disease is difficult. In this report, we describe the case of a 13-year-old boy with a bilateral thalamic germinoma which initially mimicked tumefactive demyelinating disease with inflammation, based on the clinical symptoms, imaging results and histology of a biopsy specimen obtained endoscopically. Upon examination of the cerebrospinal fluid, oligoclonal bands were detected. Although his symptoms and radiological findings improved following steroid pulse treatment, they worsened dramatically almost 1 year after the first surgery and even after an additional steroid pulse treatment. Prompted by the clinical course, a second biopsy was performed, and a pathological examination of the specimen showed a two-cell pattern. The diagnosis was changed to intracranial germinoma. After chemotherapeutic treatment with etoposide and cisplatin, the patient's symptoms and radiological findings dramatically improved. We conclude that it is very challenging to distinguish germinomas with a granulomatous reaction due to other inflammatory diseases, especially when only small specimens can be obtained. Stereotactic or endoscopic biopsies should be performed using samples from several different points even if the lesions are associated with eloquent brain regions. © 2016 S. Karger AG, Basel.

  18. Bartonella henselae Infection: An Uncommon Mimicker of Autoimmune Disease

    Science.gov (United States)

    Maritsi, Despoina N.; Zarganis, Diagoras; Metaxa, Zoi; Papaioannou, Georgia; Vartzelis, George

    2013-01-01

    We present a case of a seven-year-old immunocompetent female patient who developed systemic symptoms mimicking an autoimmune rather than an infectious disease. The patient presented with rash, biquotidian fever, night sweats, and arthralgias. There was no antecedent history of cat contact. Investigations showed increased inflammatory markers, leukocytosis, thrombocytosis, hypercalcemia, and raised angiotensin-converting enzyme. Interferon-gamma releasing assay for tuberculosis infection was negative. Abdominal imaging demonstrated multifocal lesions of the liver and spleen (later proved to be granulomata), chest X-ray showed enlarged hilar lymph nodes, and ophthalmology review revealed uveitis. Clinical, laboratory, and imaging features pointed towards sarcoidosis. Subsequently, raised titers (IgM 1 : 32, IgG 1 : 256) against Bartonella confirmed the diagnosis of B. henselae infection. She was treated with gentamycin followed by ciprofloxacin; repeat investigations showed complete resolution of findings. The presence of hepatic and splenic lesions in children with bartonellosis is well documented. Our case, however, exhibited certain unusual findings such as the coexistence of acute ocular and systemic involvement in an immunocompetent host. Serological testing is an inexpensive and effective way to diagnose bartonellosis in immunocompetent patients; we suggest that bartonella serology is included in the baseline tests performed on children with prolonged fever even in the absence of contact with cats in countries where bartonellosis is prevalent. PMID:23424700

  19. Retinal pigmentary changes in chronic uveitis mimicking retinitis pigmentosa.

    Science.gov (United States)

    Sevgi, D Damla; Davoudi, Samaneh; Comander, Jason; Sobrin, Lucia

    2017-05-18

    To present retinal pigmentary changes mimicking retinitis pigmentosa (RP) as a finding of advanced uveitis. We retrospectively reviewed charts of patients without a family history of inherited retinal degenerations who presented with retinal pigment changes and signs of past or present intraocular inflammation. Comprehensive eye examination including best-corrected visual acuity, slit-lamp examination and dilated fundus examination was performed on all patients in addition to color fundus photography, optical coherence tomography, fluorescein angiography (FA), and full-field electroretinogram testing. We identified five patients with ages ranging from 33 to 66 years, who presented with RP-like retinal pigmentary changes which were eventually attributed to longstanding uveitis. The changes were bilateral in three cases and unilateral in two cases. Four of five cases presented with active inflammation, and the remaining case showed evidence of active intraocular inflammation during follow-up. This study highlights the overlapping features of advanced uveitis and RP including the extensive pigmentary changes. Careful review of possible past uveitis history, detailed examination of signs of past or present inflammation and ancillary testing, with FA often being most helpful, are required for the correct diagnosis. This is important, because intervention can prevent further damage if the cause of the pigmentary changes is destructive inflammation.

  20. Toxicology Analysis of Tissue-Mimicking Phantom Made From Gelatin

    Science.gov (United States)

    Dolbashid, A. S.; Hamzah, N.; Zaman, W. S. W. K.; Mokhtar, M. S.

    2017-06-01

    Skin phantom mimics the biological skin tissues as it have the ability to respond to changes in its environment. The development of tissue-mimicking phantom could contributes towards the reduce usage of animal in cosmetics and pharmacokinetics. In this study, the skin phantoms made from gelatin were tested with four different commonly available cosmetic products to determine the toxicity of each substance. The four substances used were; mercury-based whitening face cream, carcinogenic liquid make-up foundation, paraben-based acne cleanser, and organic lip balm. Toxicity test were performed on all of the phantoms. For toxicity testing, topographical and electrophysiological changes of the phantoms were evaluated. The ability of each respective phantom to react with mild toxic substances and its electrical resistance were analysed in to determine the toxicity of all the phantom models. Four-electrode method along with custom made electrical impedance analyser was used to differentiate electrical resistance between intoxicated phantom and non-intoxicated phantom in this study. Electrical resistance values obtained from the phantom models were significantly higher than the control group. The result obtained suggests the phantom as a promising candidate to be used as alternative for toxicology testing in the future.

  1. A series of parapharyngeal glial heterotopia mimicking lymphatic malformation.

    Science.gov (United States)

    Haloob, Nora; Pepper, Christopher; Hartley, Benjamin

    2015-12-01

    Otolaryngologists will most frequently encounter extra-cranial glial tissue within the nasal cavity, where it is known as a 'nasal glioma', and may communicate with the dura. However, glial tissue can also present extra-nasally in the form of a neck mass with no intracranial connection. In these rare cases, they can present soon after birth as an enlarging neck mass, causing compressive symptoms with airway obstruction and feeding difficulties. In this way, it is often initially misdiagnosed as a more common lesion such as a lymphatic malformation, teratoma, branchial anomaly or vascular malformation. As with many congenital head and neck masses, offering the most the appropriate management relies heavily on radiological imaging and, where possible, histopathology from a diagnostic biopsy. Once the diagnosis of extra-nasal glial heterotopia has been confirmed, the gold standard management is complete surgical excision. We review three cases of extra-nasal glial heterotopia presenting to our institution over an eleven year period as a large neck mass, which mimicked other congenital neck lumps, and discuss them in the context of those in the literature. We highlight how their clinical and radiological features can easily be confused with lymphatic malformations, and the potential implications of misdiagnosis. Raising awareness of this diagnostic confusion will highlight the need for management of these cases within an appropriate paediatric multidisciplinary setting. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Bartonella henselae Infection: An Uncommon Mimicker of Autoimmune Disease

    Directory of Open Access Journals (Sweden)

    Despoina N. Maritsi

    2013-01-01

    Full Text Available We present a case of a seven-year-old immunocompetent female patient who developed systemic symptoms mimicking an autoimmune rather than an infectious disease. The patient presented with rash, biquotidian fever, night sweats, and arthralgias. There was no antecedent history of cat contact. Investigations showed increased inflammatory markers, leukocytosis, thrombocytosis, hypercalcemia, and raised angiotensin-converting enzyme. Interferon-gamma releasing assay for tuberculosis infection was negative. Abdominal imaging demonstrated multifocal lesions of the liver and spleen (later proved to be granulomata, chest X-ray showed enlarged hilar lymph nodes, and ophthalmology review revealed uveitis. Clinical, laboratory, and imaging features pointed towards sarcoidosis. Subsequently, raised titers (IgM 1 : 32, IgG 1 : 256 against Bartonella confirmed the diagnosis of B. henselae infection. She was treated with gentamycin followed by ciprofloxacin; repeat investigations showed complete resolution of findings. The presence of hepatic and splenic lesions in children with bartonellosis is well documented. Our case, however, exhibited certain unusual findings such as the coexistence of acute ocular and systemic involvement in an immunocompetent host. Serological testing is an inexpensive and effective way to diagnose bartonellosis in immunocompetent patients; we suggest that bartonella serology is included in the baseline tests performed on children with prolonged fever even in the absence of contact with cats in countries where bartonellosis is prevalent.

  3. A retained plastic protective cover mimicking malignancy: Case report.

    Science.gov (United States)

    Ozsoy, Mustafa; Celep, Bahadır; Ozsan, Ismail; Bal, Ahmet; Ozkececi, Ziya Taner; Arikan, Yuksel

    2013-01-01

    Cases of retained foreign bodies during surgery are more frequently seen in developing countries. Following surgical procedures, unintentionally retained foreign bodies can cause serious complications, in addition to medico-legal issues. A 60-year-old man presented with abdominal cramps. He had previously undergone a laparoscopic radical right nephrectomy due to renal cell carcinoma. Abdominal tomography revealed a mass surrounding the main vascular structures with malignant features in the location of previously performed nephrectomy. Further evaluation of the mass was undertaken by PET/CT. Increased FDG uptake on the PET/CT scan suggested disease recurrence. Retroperitoneal lymph node dissection was performed. The dissection specimen was opened to determine the nature of the mass. Retained plastic foreign bodies were found. There were no malignant cells in the histopathological examination of the surgical specimen. A granulomatous reaction which is mainly responsible for morbidity occurs around the foreign bodies due to the inflammatory response. These granulomas may cause confusion during patient follow-up, especially in those who have undergone major abdominal surgery due to cancer. Following surgical resection for malignancy, unintentionally retained foreign bodies can produce a moderate increase in FDG uptake mimicking disease recurrence. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Extramedullary Plasmacytoma Mimicking Pancreatic Cancer: An Unusual Presentation

    Directory of Open Access Journals (Sweden)

    Daniela Sciancalepore

    2016-01-01

    Full Text Available Multiple myeloma is a plasma cell tumor that homes to and expands in the bone marrow and that, despite the new available drugs, remains incurable. Extramedullary plasmacytoma is a not frequent manifestation during the natural history of multiple myeloma and is frequently associated with plasma cell bone marrow infiltration. The most common locations for an EMP include the gastrointestinal tract, pleura, testis, skin, peritoneum, liver, endocrine glands, and lymph nodes. Primary involvement of the gallbladder fossa is exceedingly rare. In this report, we describe a patient with multiple myeloma who achieved a clinical and serological remission after autologous transplant but progressed rapidly at extramedullary site mimicking a second cancer (i.e., pancreatic or biliary cancer. In this case, the extramedullary localization was refractory to standard therapy, differently from bone marrow localization, but responded to lymphoma-like therapy. In this patient (i the particular site of developing plasmacytoma is the gallbladder fossa, (ii the timing of onset of this neoplasm is immediately after autologous transplant, and (iii its disjunction from primary myeloma is that it appears in clinical and serological remission phase which may be confounding during the diagnostic approach simulating a different tumor (solid tumor.

  5. Wernicke's Encephalopathy Mimicking Acute Onset Stroke Diagnosed by CT Perfusion

    Directory of Open Access Journals (Sweden)

    Alok Bhan

    2014-01-01

    Full Text Available Background. Metabolic syndromes such as Wernicke’s encephalopathy may present with a sudden neurological deficit, thus mimicking acute onset stroke. Due to current emphasis on rapid admission and treatment of acute stroke patients, there is a significant risk that these stroke mimics may end up being treated with thrombolysis. Rigorous clinical and radiological skills are necessary to correctly identify such metabolic stroke mimics, in order to avoid doing any harm to these patients due to the unnecessary use of thrombolysis. Patient. A 51-year-old Caucasian male was admitted to our hospital with suspicion of an acute stroke due to sudden onset dysarthria and unilateral facial nerve paresis. Clinical examination revealed confusion and dysconjugate gaze. Computed tomography (CT including a CT perfusion (CTP scan revealed bilateral thalamic hyperperfusion. The use of both clinical and radiological findings led to correctly diagnosing Wernicke’s encephalopathy. Conclusion. The application of CTP as a standard diagnostic tool in acute stroke patients can improve the detection of stroke mimics caused by metabolic syndromes as shown in our case report.

  6. Regional Pericarditis Mimicking Inferior Myocardial Infarction following Abdominal Surgery

    Directory of Open Access Journals (Sweden)

    Ahmad T. Alhammouri

    2014-01-01

    Full Text Available Acute pericarditis is common but illusive, often mimicking acute coronary syndrome in its clinical and electrocardiographic presentation. Regional pericarditis, though rare, presents further challenge with a paucity of published diagnostic criteria. We present a case of postoperative regional pericarditis and discuss helpful electrocardiographic findings. A 66-year-old male with history of open drainage of a liver abscess presented with abdominal pain and tenderness. CT of the abdomen was concerning for pneumatosis intestinalis of the distal descending colon. He underwent lysis of liver adhesions; exploration revealed only severe colonic impaction, for which he had manual disimpaction and peritoneal irrigation. Postoperatively, he developed sharp chest pain. Electrocardiogram revealed inferior ST elevation. Echocardiogram revealed normal left and right ventricular dimensions and systolic function without wall motion abnormalities. Emergent coronary angiography did not identify a culprit lesion, and left ventriculogram showed normal systolic function without wall motion abnormalities. He received no intervention, and the diagnosis of regional pericarditis was entertained. His cardiac troponin was 0.04 ng/dL and remained unchanged, with resolution of the ECG abnormalities in the following morning. Review of his preangiography ECG revealed PR depression, downsloping baseline between QRS complexes, and reciprocal changes in the anterior leads, suggestive of regional pericarditis.

  7. Osteopoikilosis: A Sign Mimicking Skeletal Metastases in a Cancer Patient

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    Hamid Nasrolahi

    2011-01-01

    Full Text Available Osteopoikilosis is a rare benign osteosclerotic bone disorder that may be misdiagnosed as skeletal metastases. Here we describe a case of coincidental breast cancer and osteopoikilosis mimicking skeletal metastases. A 41-year-old woman underwent right modified radical mastectomy in April 2007. Twenty-eight months after initial treatment,the patient complained of bilateral knee and foot pain. Plain X-rays of the feet and knees showed multiple well-defined osteosclerotic lesions. According to the radiographic appearance, the most likely differential diagnoses included skeletal metastases from breast cancer and osteopoikilosis. A whole-body bone scintigraphy showed no increase in uptake by the sclerotic lesions, and serum lactic dehydrogenase, carcinoembryonic antigen, alkaline phosphatase and cancer antigen 15-3 were not elevated. We therefore diagnosed the patient’s skeletal lesions as osteopoikilosis. This case and ourliterature review suggest that the radiographic appearance of osteopoikilosis may mimic or mask skeletal metastases, potentially leading to misdiagnosis in patients with cancer.

  8. Unusual ovarian stromal tumor with radiation changes mimicking carcinoma.

    Science.gov (United States)

    Bohn, Olga L; Zhao, Chengquan; Jones, Mirka W

    2011-04-27

    Radiation-related changes including fibrosis, nuclear enlargement, hyperchromasia and cytoplasmic vacuolization may alter the appearance of normal ovarian tissue and ovarian tumors. We describe radiation-related changes in ovarian stromal neoplasm with mixed features of sclerosing stromal tumor and fibrothecoma. The right ovarian mass was discovered in a 38 year-old woman with past history of invasive squamous cell carcinoma of the cervix treated with cone biopsy and brachytherapy. The low power architecture of cellular pseudolobules and small sheets of tumor cells with scattered hyaline plaques was consisted with the pattern of combined sclerosing stromal tumor and fibrothecoma. However, the presence of severe cytologic atypia, as well as clear cell and signet ring differentiation and arrangements of tumor cells in single files and nests, raised a possibility of primary or metastatic carcinoma. The tumor cells were positive for calretinin, vimentin, inhibin, and WT1 and negative for AE1/3, cytokeratin 7 and 20, CD99, estrogen and progesterone receptors, mammaglobin, chromogranin, and S100 protein. Based on the results of immunostains and a subsequently provided history of radiation, a diagnosis of sex cord stromal tumor with mixed fibrothecoma and sclerosing stromal differentiation was made. Radiation-related atypia and fibrosis in sex cord stromal tumor may create a pattern mimicking carcinoma and therefore, in the presence of unusual histology, the use of immunohistochemistry is recommended.

  9. Unusual Ovarian Stromal Tumor with Radiation Changes Mimicking Carcinoma

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    Olga L. Bohn, Chengquan Zhao, Mirka W. Jones

    2011-01-01

    Full Text Available Radiation-related changes including fibrosis, nuclear enlargement, hyperchromasia and cytoplasmic vacuolization may alter the appearance of normal ovarian tissue and ovarian tumors. We describe radiation-related changes in ovarian stromal neoplasm with mixed features of sclerosing stromal tumor and fibrothecoma. The right ovarian mass was discovered in a 38 year-old woman with past history of invasive squamous cell carcinoma of the cervix treated with cone biopsy and brachytherapy. The low power architecture of cellular pseudolobules and small sheets of tumor cells with scattered hyaline plaques was consisted with the pattern of combined sclerosing stromal tumor and fibrothecoma. However, the presence of severe cytologic atypia, as well as clear cell and signet ring differentiation and arrangements of tumor cells in single files and nests, raised a possibility of primary or metastatic carcinoma. The tumor cells were positive for calretinin, vimentin, inhibin, and WT1 and negative for AE1/3, cytokeratin 7 and 20, CD99, estrogen and progesterone receptors, mammaglobin, chromogranin, and S100 protein. Based on the results of immunostains and a subsequently provided history of radiation, a diagnosis of sex cord stromal tumor with mixed fibrothecoma and sclerosing stromal differentiation was made. Radiation-related atypia and fibrosis in sex cord stromal tumor may create a pattern mimicking carcinoma and therefore, in the presence of unusual histology, the use of immunohistochemistry is recommended.

  10. A New System for Understanding Mid-crustal Sheeted Complexes in a Tilted Crustal Section, Joshua Tree National Park, California

    Science.gov (United States)

    Ianno, A. J.; Paterson, S. R.

    2011-12-01

    The western portion of Joshua Tree National Park exposes a tilted crustal section through continental arc crust from 0-30 km. A significant portion of the middle crust is represented by Mesozoic, tabular, intrusive, igneous bodies ranging from 0.1 to 100 m in thickness. While these igneous bodies range in composition (gabbro to peraluminous granites), texture (equigranular to porphyritic), and grain size (very fine to coarse), patterns emerge between different regions of "sheeted complexes" that may be related to their emplacement and geochemical history. No consistent method of describing and comparing sheeted complexes exists in the literature, so we have developed a method of classifying sheeted complexes at Joshua Tree NP, which may be broadly applicable to all sheeted bodies. We classify these sheeted complexes using the terms homogeneous/heterogeneous and focused/defocused. A homogeneous sheeted complex generally contains magmas within a 10 wt% SiO2 range, although we are still testing the validity of this number. A focused sheeted complex has adjacent sheets or close spacing between sheets and Jurassic to Cretaceous sheeted complexes in western Joshua Tree NP. At Keys View, we observe a heterogeneous, spatially focused sheeted complex with 0.1-2 m thick sheets recording pressures indicating 15-22 km depth from top to bottom. Compositions range from gabbro to peraluminous granite, although tonalites-granodiorites and two-mica garnet granites are volumetrically dominant. A zone of elongate plutons (in map view) lying structurally above this could potentially be considered as a very thickly sheeted, homogeneous, focused sheeted complex and is composed of granodiorites, granites, and two-mica garnet granites. A more thickly sheeted (2-10 m), homogeneous, focused, sheeted granite complex with pressures indicating a depth of approximately 12 km is found along the northern edge of the park. The number of sheets decreases and the average thickness increases as this

  11. Global Mapping of Oceanic and Continental Shelf Crustal Thickness and Ocean-Continent Transition Structure

    Science.gov (United States)

    Kusznir, Nick; Alvey, Andy; Roberts, Alan

    2017-04-01

    The 3D mapping of crustal thickness for continental shelves and oceanic crust, and the determination of ocean-continent transition (OCT) structure and continent-ocean boundary (COB) location, represents a substantial challenge. Geophysical inversion of satellite derived free-air gravity anomaly data incorporating a lithosphere thermal anomaly correction (Chappell & Kusznir, 2008) now provides a useful and reliable methodology for mapping crustal thickness in the marine domain. Using this we have produced the first comprehensive maps of global crustal thickness for oceanic and continental shelf regions. Maps of crustal thickness and continental lithosphere thinning factor from gravity inversion may be used to determine the distribution of oceanic lithosphere, micro-continents and oceanic plateaux including for the inaccessible polar regions (e.g. Arctic Ocean, Alvey et al.,2008). The gravity inversion method provides a prediction of continent-ocean boundary location which is independent of ocean magnetic anomaly and isochron interpretation. Using crustal thickness and continental lithosphere thinning factor maps with superimposed shaded-relief free-air gravity anomaly, we can improve the determination of pre-breakup rifted margin conjugacy and sea-floor spreading trajectory during ocean basin formation. By restoring crustal thickness & continental lithosphere thinning to their initial post-breakup configuration we show the geometry and segmentation of the rifted continental margins at their time of breakup, together with the location of highly-stretched failed breakup basins and rifted micro-continents. For detailed analysis to constrain OCT structure, margin type (i.e. magma poor, "normal" or magma rich) and COB location, a suite of quantitative analytical methods may be used which include: (i) Crustal cross-sections showing Moho depth and crustal basement thickness from gravity inversion. (ii) Residual depth anomaly (RDA) analysis which is used to investigate OCT

  12. Gliomatosis cerebri mimicking encephalitis evaluated using fluorine-18 fluorodeoxyglucose: Positron emission tomography/computed tomography.

    Science.gov (United States)

    Kamaleshwaran, Koramadai Karuppusamy; Krishnan, Vijayan; Mohanan, Vyshakh; Shibu, Deepu; Shinto, Ajit Sugunan

    2015-01-01

    Gliomatosis cerebri (GC) is a rare condition in which an infiltrative glial neoplasm spreads through the brain with preservation of the underlying structure. F-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has an important role in demonstrating the appropriate metabolism and differentiating pathologies mimicking GC on CT and magnetic resonance imaging. We describe imaging findings of FDG PET/CT in GC in a 9-year-old male child mimicking encephalitis.

  13. Decrease in oceanic crustal thickness since the breakup of Pangaea

    Science.gov (United States)

    van Avendonk, Harm J. A.; Davis, Joshua K.; Harding, Jennifer L.; Lawver, Lawrence A.

    2017-01-01

    Earth's mantle has cooled by 6-11 °C every 100 million years since the Archaean, 2.5 billion years ago. In more recent times, the surface heat loss that led to this temperature drop may have been enhanced by plate-tectonic processes, such as continental breakup, the continuous creation of oceanic lithosphere at mid-ocean ridges and subduction at deep-sea trenches. Here we use a compilation of marine seismic refraction data from ocean basins globally to analyse changes in the thickness of oceanic crust over time. We find that oceanic crust formed in the mid-Jurassic, about 170 million years ago, is 1.7 km thicker on average than crust produced along the present-day mid-ocean ridge system. If a higher mantle temperature is the cause of thicker Jurassic ocean crust, the upper mantle may have cooled by 15-20 °C per 100 million years over this time period. The difference between this and the long-term mantle cooling rate indeed suggests that modern plate tectonics coincide with greater mantle heat loss. We also find that the increase of ocean crustal thickness with plate age is stronger in the Indian and Atlantic oceans compared with the Pacific Ocean. This observation supports the idea that upper mantle temperature in the Jurassic was higher in the wake of the fragmented supercontinent Pangaea due to the effect of continental insulation.

  14. Anomalous crustal movements before great Wenchuan earthquake observed by GPS

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    Gu Guohua

    2011-05-01

    Full Text Available Studies of GPS data carried out before and after the great Wenchuan earthquake of Ms8.0 on May 12, 2008 show that anomalous crustal movements occurred before the earthquake. Data from 4 pre-earthquake observation sessions at a dense network of stations show that there were prominent broad-ranged long- and mid-term anomalies in horizontal displacements and strain and in vertical displacements. Data from the fewer-numbered reference stations of continuous GPS observations since 1999 in West and South China showed short-term preseismic anomalies in horizontal displacements. The detection of co-seismic horizontal displacements at these stations supports the existence of the pre-earthquake anomalies. Results of single-epoch solutions of data from continuous-observation stations near the epicenter also show large imminent anomalies in vertical displacements. Although the Wenchuan earthquake was not predicted, these results give a strong indication that GPS should be the main observation technique for long-term, mid-term, short-term and imminent earthquake predictions.

  15. Maps of North American crustal stability and geothermal potential

    Energy Technology Data Exchange (ETDEWEB)

    Fairbridge, R.W.

    1977-01-01

    A three-year program of analysis of crustal movements in North America was planned with the objective of preparing a series of 1 = 5 million scale maps depicting relative stability/instability. The part of the proposal completed during the first year is described; much of this first year's work was preparatory. Three time scales were considered for the data analysis: 1 - 10/sup 2/ yr., 10/sup 4/ yr., and 10/sup 8/ yr. Significant differences in sign and rate were suspected between short and long-term motions and these are now confirmed. The first part of the program is now complete. It consisted of two principal activities: (a) data collection for the short and mid-term scales on a U.S.-wide basis, excluding Alaska and Hawaii (all of this material has been reduced to compatible computer language and is stored on tape ready for further study, analysis and final cartography); (b) map and data analysis of the long-term scale with a completed draft map, applied specifically to the Mid-West and eastern U.S.

  16. Present three-dimensional crustal deformation in Hainan Island

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    Hu Yaxuan

    2014-05-01

    Full Text Available Hainan Island, located at the southeast edge of the Eurasian Plate, is affected by the motion of multiple plates, with its northeast edge mainly dilatating and its western margin presently compressing. By analyzing the GPS rates during 1999 – 2007 in Hainan and its adjacent region, we determined horizontal movement rates of 3. 0–21. 1 mm/a at the west of 104°E, evidently affected by the Indian Plate extrusion. Their directions are SE-SN-SW from east to west and are separated by the main fault. The principal strains have the same characteristics. The stations east of 104°E move mainly in the SEE direction. The eastward rates are 2. 1–8. 5 mm/a and northward rates are 0. 4–2. 7 mm/a. The GPS rates during 2009–2013 show that stations at the edge of the island move SEE relative to the Eurasian Plate, with rates relative to the mean benchmark, indicating that there are small relative movements between stations, whereas QION station, located in the middle, moves in the NW direction at a greater rate. Vertical differential movement is apparent in the northeast zone of the island. Upwelling of mantle plume material possibly influences the local stress. Three-dimensional GPS rates indicate that, at present, inherited crustal movement is dominant in Hainan.

  17. Lifetime and size of shallow magma bodies controlled by crustal-scale magmatism

    OpenAIRE

    Karakas, Ozge; Degruyter, Wim; Bachmann, Olivier; Dufek, Josef

    2017-01-01

    Magmatic processes on Earth govern the mass, energy and chemical transfer between the mantle, crust and atmosphere. To understand magma storage conditions in the crust that ultimately control volcanic activity and growth of continents, an evaluation of the mass and heat budget of the entire crustal column during magmatic episodes is essential. Here we use a numerical model to constrain the physical conditions under which both lower and upper crustal magma bodies form. We find that over long d...

  18. Estimating gravity changes caused by crustal strain: application to the Tibetan Plateau

    Science.gov (United States)

    Yin, Zhi; Xu, Caijun

    2017-08-01

    Temporal gravimetry is an efficient tool for monitoring mass transfers, but distinguishing the contribution of each process to the measured signals is challenging. Few effective methods have been developed to estimate the changes in gravity caused by crustal strain for large-scale geophysical problems. To fill this research gap, we proposed a formula that describes a negative linear correlation between changes in gravity and crustal dilatational strain. Surface observations of gravity changes and dilatational strains were simulated using PSGRN/PSCMP, which is a numerical code used to calculate the surface response to fault dislocations, and the accuracy of the formula was quantitatively verified. Four parameters are required for this formula: the crustal dilatational strain, the crustal density, the Moho depth, and a coefficient that characterizes the degree of crust-mantle coupling. To illustrate the application of this new method to a natural case study, including specifying the values of the necessary parameters, the crustal strain-caused gravity changes (CSGCs) were calculated at 1° × 1° grid nodes over the Tibetan Plateau (TP). The CSGC model shows that most of the crust of the TP is undergoing extension, which generates negative gravity signals. The magnitude of the Tibetan CSGC model is approximately 0.2 μGal yr-1, which is similar to the results obtained from numerical modelling of the crustal tectonics of the Taiwanese Orogen. To evaluate the reliability of the Tibetan CSGC model, the uncertainties in the crustal dilatational strain, crustal density, Moho depth, and crust-mantle coupling factor were evaluated and then used to estimate the CSGC uncertainty by applying the error propagation law. The CSGC model was used to analyse the mass transfers of the TP. The results suggest that a significant mass accumulation process may be occurring beneath the crust of the northern TP.

  19. Use of MAGSAT anomaly data for crustal structure and mineral resources in the US midcontinent

    Science.gov (United States)

    Carmichael, R. S.

    1983-01-01

    Magnetic field data acquired by NASA's MAGSAT satellite is used to construct a long-wavelength magnetic anomaly map for the U.S. midcontinent. This aids in interpretation of gross crustal geology (structure, lithologic composition, resource potential) of the region. Magnetic properties of minerals and rocks are investigated and assessed, to help in evaluation and modelling of crustal magnetization sources and depth to the Curie-temperature isotherm.

  20. Measurement of guided mode wavenumbers in soft tissue-bone mimicking phantoms using ultrasonic axial transmission

    Science.gov (United States)

    Chen, Jiangang; Foiret, Josquin; Minonzio, Jean-Gabriel; Talmant, Maryline; Su, Zhongqing; Cheng, Li; Laugier, Pascal

    2012-05-01

    Human soft tissue is an important factor that influences the assessment of human long bones using quantitative ultrasound techniques. To investigate such influence, a series of soft tissue-bone phantoms (a bone-mimicking plate coated with a layer of water, glycerol or silicon rubber) were ultrasonically investigated using a probe with multi-emitter and multi-receiver arrays in an axial transmission configuration. A singular value decomposition signal processing technique was applied to extract the frequency-dependent wavenumbers of several guided modes. The results indicate that the presence of a soft tissue-mimicking layer introduces additional guided modes predicted by a fluid waveguide model. The modes propagating in the bone-mimicking plate covered by the soft-tissue phantom are only slightly modified compared to their counterparts in the free bone-mimicking plate, and they are still predicted by an elastic transverse isotropic two-dimensional waveguide. Altogether these observations suggest that the soft tissue-bone phantoms can be modeled as two independent waveguides. Even in the presence of the overlying soft tissue-mimicking layer, the modes propagating in the bone-mimicking plate can still be extracted and identified. These results suggest that our approach can be applied for the purpose of the characterization of the material and structural properties of cortical bone.

  1. Crustal Structure across The Southwest Longmenshan Fault Zone from Seismic Wide Angle Reflection/Refraction Profile

    Science.gov (United States)

    Tian, Xiaofeng; Wang, Fuyun; Wang, Shuaijun; Duan, Yonghong

    2014-05-01

    The Lushan eathquake, which epicenter and focal depth were at 30.308° N, 102.888° E, and 14.0 km, is the latest intense earthquake occurring in the southwest section of the Longmenshan fault zone after the Ms 8.0 Wenchuan earthquake in 2008. According to the emergency field observations, the slip distribution of the Lushan earthquake was concentrated at the hypocenter, and did not rupture to the surface(Chen et al, 2013). The rupture history constrained by inverting waveforms showed that the causative fault plane of the Lushan event is apparently not a simple extension of either the Pengguan fault or the Beichuan fault that ruptured during the 2008 Mw 8.0 Wenchuan earthquake. The focal mechanism using the Cut and Paste algorithm showed this event occurred on a high dip-angle fault, but its dip angle is not steep enough to rupture the surface. All these research is not independent on the heterogeneous crust structure of the Longmenshan fault zone. A 450 km-long wide-angle reflection/refraction profile executed during September and October 2013. This experiment have provided the best opportunities to obtain better knowledge of seismic structure and properties of crust and uppermost mantle beneath the Southwest Longmenshan fault zone. This seismic profile extends from the west Sichuan Plain, through the Longmenshan Fault zone, and into the west Sichuan Plateau. We observed clear Pg, refraction Phase from the upper crust, Pi1/Pi2/Pi3, reflection/refraction Phase from intra-crust, PmP, reflection from the Moho boundary, and the Pn phase, refraction Phase from uppermost mantle. We present a hybrid tomographic and layered velocity model of the crust and uppermost mantle along the profile. The final velocity model reveals large variations both in structure and velocity, and is demonstrated that a particular model has minimum structure. The model shows the crustal thickness of the region is very variable. The Moho topography varies more than 10km in the southwest

  2. Tissue mimicking simulations for temporal enhanced ultrasound-based tissue typing

    Science.gov (United States)

    Bayat, Sharareh; Imani, Farhad; Gerardo, Carlos D.; Nir, Guy; Azizi, Shekoofeh; Yan, Pingkun; Tahmasebi, Amir; Wilson, Storey; Iczkowski, Kenneth A.; Lucia, M. Scott; Goldenberg, Larry; Salcudean, Septimiu E.; Mousavi, Parvin; Abolmaesumi, Purang

    2017-03-01

    Temporal enhanced ultrasound (TeUS) is an imaging approach where a sequence of temporal ultrasound data is acquired and analyzed for tissue typing. Previously, in a series of in vivo and ex vivo studies we have demonstrated that, this approach is effective for detecting prostate and breast cancers. Evidences derived from our experiments suggest that both ultrasound-signal related factors such as induced heat and tissue-related factors such as the distribution and micro-vibration of scatterers lead to tissue typing information in TeUS. In this work, we simulate mechanical micro-vibrations of scatterers in tissue-mimicking phantoms that have various scatterer densities reflecting benign and cancerous tissue structures. Finite element modeling (FEM) is used for this purpose where the vertexes are scatterers representing cell nuclei. The initial positions of scatterers are determined by the distribution of nuclei segmented from actual digital histology scans of prostate cancer patients. Subsequently, we generate ultrasound images of the simulated tissue structure using the Field II package resulting in a temporal enhanced ultrasound. We demonstrate that the micro-vibrations of scatterers are captured by temporal ultrasound data and this information can be exploited for tissue typing.

  3. Humans mimicking animals: A cortical hierarchy for human vocal communication sounds

    Science.gov (United States)

    Talkington, William J.; Rapuano, Kristina M.; Hitt, Laura; Frum, Chris A.; Lewis, James W.

    2012-01-01

    Numerous species possess cortical regions that are most sensitive to vocalizations produced by their own kind (conspecifics). In humans, the superior temporal sulci (STS) putatively represent homologous voice-sensitive areas of cortex. However, STS regions have recently been reported to represent auditory experience or “expertise” in general rather than showing exclusive sensitivity to human vocalizations per se. Using functional magnetic resonance imaging and a unique non-stereotypical category of complex human non-verbal vocalizations – human-mimicked versions of animal vocalizations – we found a cortical hierarchy in humans optimized for processing meaningful conspecific utterances. This left-lateralized hierarchy originated near primary auditory cortices and progressed into traditional speech-sensitive areas. These results suggest that the cortical regions supporting vocalization perception are initially organized by sensitivity to the human vocal tract in stages prior to the STS. Additionally, these findings have implications for the developmental time course of conspecific vocalization processing in humans as well as its evolutionary origins. PMID:22674283

  4. Control of early-formed vesicle cylinders on upper crustal prismatic jointing in compound pāhoehoe lavas of Elephanta Island, western Deccan Traps, India

    Science.gov (United States)

    Sheth, Hetu; Patel, Vanit; Samant, Hrishikesh

    2017-08-01

    Upper crustal prismatic joints and vesicle cylinders, common in pāhoehoe lava flows, form early and late, respectively, and are therefore independent features. However, small-scale compound pāhoehoe lava lobes on Elephanta Island (western Deccan Traps, India), which resemble S-type (spongy) pāhoehoe in some aspects, contain vesicle cylinders which apparently controlled the locations of upper crustal prismatic joints. The lobes are decimeters thick, did not experience inflation after emplacement, and solidified rapidly. They have meter-scale areas that are exceptionally rich in vesicle cylinders (up to 68 cylinders in 1 m2, with a mean spacing of 12.1 cm), separated by cylinder-free areas, and pervasive upper crustal prismatic jointing with T, curved T, and quadruple joint intersections. A majority (≥76.5%) of the cylinders are located exactly on joints or at joint intersections, and were not simply captured by downward growing joints, as the cylinders show no deflection in vertical section. We suggest that large numbers of cylinders originated in a layer of bubble-rich residual liquid at the top of a basal diktytaxitic crystal mush zone which was formed very early (probably within the first few minutes of the emplacement history). The locations where the rising cylinders breached the crust provided weak points or mechanical flaws towards which any existing joints (formed by thermal contraction) propagated. New joints may also have propagated outwards from the cylinders and linked up laterally. Some cylinders breached the crust between the joints, and thus formed a little later than most others. The Elephanta Island example reveals that, whereas thermal contraction is undoubtedly valid as a standard mechanism for forming upper crustal prismatic joints, abundant mechanical flaws (such as large concentrations of early-formed, crust-breaching vesicle cylinders) can also control the joint formation process.

  5. Crustal strain-dependent serpentinisation in the Porcupine Basin, offshore Ireland

    Science.gov (United States)

    Prada, Manel; Watremez, Louise; Chen, Chen; O'Reilly, Brian M.; Minshull, Timothy A.; Reston, Tim J.; Shannon, Patrick M.; Klaeschen, Dirk; Wagner, Gerlind; Gaw, Viola

    2017-09-01

    Mantle hydration (serpentinisation) at magma-poor rifted margins is thought to play a key role in controlling the kinematics of low-angle faults and thus, hyperextension and crustal breakup. However, because geophysical data principally provide observations of the final structure of a margin, little is known about the evolution of serpentinisation and how this governs tectonics during hyperextension. Here we present new observational evidence on how crustal strain-dependent serpentinisation influences hyperextension from rifting to possible crustal breakup along the axis of the Porcupine Basin, offshore Ireland. We present three new P-wave seismic velocity models that show the seismic structure of the uppermost lithosphere and the geometry of the Moho across and along the basin axis. We use neighbouring seismic reflection lines to our tomographic models to estimate crustal stretching (βc) of ∼2.5 in the north at 52.5° N and >10 in the south at 51.7° N. These values suggest that no crustal embrittlement occurred in the northernmost region, and that rifting may have progressed to crustal breakup in the southern part of the study area. We observed a decrease in mantle velocities across the basin axis from east to west. These variations occur in a region where βc is within the range at which crustal embrittlement and serpentinisation are possible (βc 3-4). Across the basin axis, the lowest seismic velocity in the mantle spatially coincides with the maximum amount of crustal faulting, indicating fault-controlled mantle hydration. Mantle velocities also suggest that the degree of serpentinisation, together with the amount of crustal faulting, increases southwards along the basin axis. Seismic reflection lines show a major detachment fault surface that grows southwards along the basin axis and is only visible where the inferred degree of serpentinisation is >15%. This observation is consistent with laboratory measurements that show that at this degree of

  6. Herpes zoster sciatica mimicking lumbar canal stenosis: a case report.

    Science.gov (United States)

    Koda, Masao; Mannoji, Chikato; Oikawa, Makiko; Murakami, Masazumi; Okamoto, Yuzuru; Kon, Tamiyo; Okawa, Akihiko; Ikeda, Osamu; Yamazaki, Masashi; Furuya, Takeo

    2015-07-29

    Symptom of herpes zoster is sometimes difficult to distinguish from sciatica induced by spinal diseases, including lumbar disc herniation and spinal canal stenosis. Here we report a case of sciatica mimicking lumbar canal stenosis. A 74-year-old Chinese male patient visited our hospital for left-sided sciatic pain upon standing or walking for 5 min of approximately 1 month's duration. At the first visit to our hospital, there were no skin lesions. A magnetic resonance imaging showed spinal canal stenosis between the 4th and 5th lumbar spine. Thus, we diagnosed the patient with sciatica induced by spinal canal stenosis. We considered decompression surgery for the stenosis of 4th and 5th lumbar spine because conservative therapy failed to relieve the patient's symptom. At that time, the patient complained of a skin rash involving his left foot for several days. A vesicular rash and erythema were observed on the dorsal and plantar surfaces of the great toe and lateral malleolus. The patient was diagnosed with herpes zoster in the left 5th lumbar spinal nerve area based on clinical findings, including the characteristics of the pain and vesicular rash and erythema in the 5th lumbar spinal dermatome. The patient was treated with famciclovir (1,500 mg/day) and non-steroidal anti-inflammatory drugs. After 1 week of medication, the skin rash resolved and pain relief was obtained. In conclusion, spinal surgeons should keep in mind herpes zoster infection as one of the possible differential diagnoses of sciatica, even if there is no typical skin rash.

  7. Chronic multifocal non-bacterial osteomyelitis in hypophosphatasia mimicking malignancy

    Directory of Open Access Journals (Sweden)

    Warmuth-Metz Monika

    2007-01-01

    Full Text Available Abstract Background Hypophosphatasia (HP is characterized by a genetic defect in the tissue-nonspecific alkaline phosphatase (TNSALP gene and predominantly an autosomal recessive trait. HP patients suffer from reduced bone mineralization. Biochemically, elevated concentrations of substrates of TNSALP, including pyridoxal-5'-phosphate and inorganic pyrophosphate occur in serum, tissues and urine. The latter has been associated with chronic inflammation and hyperprostaglandinism. Case presentation We report on 2 affected children presenting with multifocal inflammatory bone lesions mimicking malignancy: A 6 years old girl with short stature had been treated with human growth hormone since 6 months. Then she started to complain about a painful swelling of her left cheek. MRI suggested a malignant bone lesion. Bone biopsy, however, revealed chronic inflammation. A bone scan showed a second rib lesion. Since biopsy was sterile, the descriptive diagnosis of chronic non-bacterial osteomyelitis (CNO was established. The diagnostic tests related to growth failure were repeated and subsequent analyses demonstrated a molecular defect in the TNSALP gene. The second girl (10 years old complained about back pain after she had fallen from her bike. X rays of her spine revealed compressions of 2 thoracic vertebrae. At first these were considered trauma related, however a bone scan did show an additional lesion in the right 4th rib. A biopsy of this rib revealed a sterile lympho- plasmocytoid osteomyelitis suggesting multifocal CNO. Further analyses did show a decreased TNSALP in leukocytes and elevated pyridoxal phosphate in plasma, suggesting a heterozygous carrier status of HP. Conclusion Chronic bone oedema in adult HP and chronic hyper-prostaglandinism in childhood HP do suggest that in some HP patients bone inflammation is present in conjunction with the metabolic defect. Sterile multifocal osteomyelitis could be demonstrated. Non-steroidal anti

  8. Atypical lymphocytes in malaria mimicking dengue infection in Thailand

    Directory of Open Access Journals (Sweden)

    Polrat Wilairatana

    2010-09-01

    Full Text Available Polrat Wilairatana1, Noppadon Tangpukdee1, Sant Muangnoicharoen1, Srivicha Krudsood2, Shigeyuki Kano31Department of Clinical Tropical Medicine, 2Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; 3Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine, Tokyo, JapanAbstract: Patients with uncomplicated falciparum or vivax malaria usually present with acute febrile illness and thrombocytopenia similar to dengue infection. We retrospectively studied atypical lymphocytes (AL and atypical lymphocytosis (ALO, defined as AL > 5% of total white blood cells in 1310 uncomplicated malaria patients. In 718 falciparum malaria patients, AL and ALO on day 0 were found in 53.2% and 5.7% of the patients, respectively, with median AL on admission of 1% (range 0%–10%, whereas in 592 vivax malaria patients, AL and ALO on day 0 were found in 55.4% and 9.5% of the patients, respectively, with median AL on admission of 1% (range 0%–14%. After antimalarial treatment, AL and ALO declined in both falciparum and vivax malaria. However, AL and ALO remained in falciparum malaria on days 7, 14, and 21, whereas AL and ALO remained in vivax malaria on days 7, 14, 21, and 28. In both falciparum and vivax malaria patients, there was a positive correlation between AL and total lymphocytes, but a negative correlation between AL and highest fever on admission, white blood cells, and neutrophils, eosinophils, and platelets (P < 0.05. In conclusion, AL or ALO may be found in uncomplicated falciparum and vivax malaria mimicking dengue infection. In tropical countries where both dengue and malaria are endemic, presence of AL or ALO in any acute febrile patients with thrombocytopenia (similar to the findings in dengue malaria could not be excluded. Particularly if the patients have risk of malaria infection, confirmative microscopic examination for malaria should be carried out

  9. Mimicking Nonequilibrium Steady States with Time-Periodic Driving

    Science.gov (United States)

    Raz, O.; Subaşı, Y.; Jarzynski, C.

    2016-04-01

    Under static conditions, a system satisfying detailed balance generically relaxes to an equilibrium state in which there are no currents. To generate persistent currents, either detailed balance must be broken or the system must be driven in a time-dependent manner. A stationary system that violates detailed balance evolves to a nonequilibrium steady state (NESS) characterized by fixed currents. Conversely, a system that satisfies instantaneous detailed balance but is driven by the time-periodic variation of external parameters—also known as a stochastic pump (SP)—reaches a periodic state with nonvanishing currents. In both cases, these currents are maintained at the cost of entropy production. Are these two paradigmatic scenarios effectively equivalent? For discrete-state systems, we establish a mapping between nonequilibrium stationary states and stochastic pumps. Given a NESS characterized by a particular set of stationary probabilities, currents, and entropy production rates, we show how to construct a SP with exactly the same (time-averaged) values. The mapping works in the opposite direction as well. These results establish a proof of principle: They show that stochastic pumps are able to mimic the behavior of nonequilibrium steady states, and vice versa, within the theoretical framework of discrete-state stochastic thermodynamics. Nonequilibrium steady states and stochastic pumps are often used to model, respectively, biomolecular motors driven by chemical reactions and artificial molecular machines steered by the variation of external, macroscopic parameters. Our results loosely suggest that anything a biomolecular machine can do, an artificial molecular machine can do equally well. We illustrate this principle by showing that kinetic proofreading, a NESS mechanism that explains the low error rates in biochemical reactions, can be effectively mimicked by a constrained periodic driving.

  10. Brugada ECG Sign & Chest Pain Mimicking ST Elevation Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Omar Mousa

    2013-11-01

    Full Text Available Background: Management of patients with the brugada ECG sign who have no previous history of syncope is still negotiable. We present a case of a 57 year-old Caucasian lady who presented to the emergency department with substernal chest pain. Results: Her past medical history showed that she had two previous episodes of lightheadedness, but no syncope. She had a family history of sudden death secondary to unknown cause in her aunt at the age of 61. Physical exam was unremarkable except for diaphoresis. Electrocardiography (ECG showed ST elevation in the right precordial leads (V1-V2 with T inversion, mimicking a STEMI. Emergent cardiac catheterization revealed normal coronary arteries. Echocardiogram was normal. Again, interpretation of ECG revealed a Brugada type 1 pattern, characterized by coved-type, gradually descending ST-T segment, elevated J point of more than 2 mm and T wave inversion. Electrophysiological (EPS testing with a Sodium channel blocker challenge showed a persistent Brugada type 1 pattern with non inducible ventricular tachycardia. This patient had Brugada type 1 ECG pattern with no previous history of syncope (asymptomatic. Thus she was considered at low risk of developing a serious arrhythmogenic event in the future. Conclusion: A history of syncope remains the best available predictor for arrhythmogenic events. EPS testing in such patients, to stratify the risk and predict for any future events, is still controversial. It is still unjustified to place an implantable cardioverter-defibrillator in asymptomatic non-inducible individuals with the Brugada pattern. These patients should follow up closely with a cardiologist and be aware of the risk of possible triggers of ventricular arrhythmias.

  11. Gout mimicking spondyloarthritis: case report and literature review

    Directory of Open Access Journals (Sweden)

    Chen W

    2017-06-01

    Full Text Available Wenji Chen,1 Yanyan Wang,2 Yan Li,2 Zheng Zhao,2 Lixia Feng,2 Jian Zhu,2 Jianglin Zhang,2 Feng Huang2 1Department of Rheumatology, Hainan Branch of Chinese People’s Liberation Army General Hospital, Sanya, 2Department of Rheumatology, Chinese People’s Liberation Army General Hospital, Beijing, People’s Republic of China Abstract: Gout is clinically characterized by episodes of monoarthritis, which not only typically affects the peripheral joints but also occasionally affect the axial joint, such as the sacroiliac joint (SIJ, and often mimics spondyloarthritis (SpA. Two cases of gout mimicking SpA are presented in the current paper. One patient was a 32-year-old man with a history of asymmetrical oligoarthritis of ankle and metatarsophalangeal joints (MTPJ. He had left gluteal pain for 2 weeks. Computed tomography (CT and magnetic resonance imaging (MRI revealed the bone erosion of the left SIJ. T1-weighted MRI showed hypointense T1 and hyperintense T2 signals of the left SIJ. The other patient was a 24-year-old man with left back pain and hip pain for 4 months and intermittent fever for 3 months. He had a history of gout for 3 years. Both patients underwent CT-guided sacroiliac biopsy, and monosodium urate (MSU crystals were shown by polarized microscopy. Gout can often mimic SpA and seldomly affects the SIJ. Thus, its correct diagnosis and adequate therapy can halt the development of such damaging complications. Keywords: gout, crystal arthropathy, sacroiliac joint, radiography

  12. The crustal structure beneath the Netherlands from ambient seismic noise

    Science.gov (United States)

    Paulssen, Hanneke; Yudistira, Tedi; Trampert, Jeannot

    2017-04-01

    A 3-D shear velocity model of the crust beneath the Netherlands is determined from fundamental mode Rayleigh and Love wave group measurements derived from ambient seismic noise recordings. The data are obtained from a temporary array of broad-band seismometers in and around the Netherlands (the NARS-Netherlands project, 2008-2012) complemented with data from existing networks in the Netherlands, Belgium and Germany. Rayleigh and Love wave group velocity maps were constructed for the period range of 10 to 30 s. Lateral variations in the group velocity maps primarily reflect variations in sedimentary thickness across the Netherlands. The 2-psi Rayleigh wave and 4-psi Love wave fast directions of the group velocity maps are in agreement with the NW-SE direction of maximum compressive stress as well as with the NW-SE dominant direction of faulting in the Netherlands. The frequency dependence suggests that the azimuthal anisotropy is caused by lattice preferred orientation (LPO) of lower crustal minerals. A 3-D shear-velocity model is obtained by inversion of the group velocity maps using the Neighbourhood Algorithm. The results show a top layer that varies in thickness from 2 to 4 km with with a pattern that is similar to the base of the Rotliegend. A midcrustal discontinuity is found at a depth of about 13 km. The Moho appears to be relatively flat with an average depth of 33 km. Radial anisotropy is mainly positive (Vsh - Vsv > 0) for the lower crust. This can be an expression of LPO but also of horizontal layering or lamination. The top layer shows the largest variations in radial anisotropy with distinct areas of negative radial anisotropy that can be attributed to high-density near-vertical faulting in those regions.

  13. Crustal structure on the northeastern flank of the Kenya rift

    Science.gov (United States)

    Prodehl, C.; Jacob, A. W. B.; Thybo, H.; Dindi, E.; Stangl, R.

    1994-09-01

    The KRISP flank line E converges with the Kenya rift at an angle of about 45° and is approximately parallel to the older Anza graben to the north. The depth to the basement is almost zero along the entire onshore part of the profile with higher velocities at the southeastern end indicative of extensive Precambrian gabbroic intrusions in the upper crust. The Moho shallows steadily from about 35 km at the southeastern end of the profile to about 24 km under Lake Turkana. Even though the Moho rises fairly steadily, there is significant heterogeneity in the crust above it. This shows that the extension is unevenly distributed between the upper and the lower crust. The Moho is laminated and variably reflective. Compared to the KRISP cross-line D further south, the crust is unexpectedly thin and shows extension increasing in a northerly direction. This extension is probably not associated with the Anza and Kenya rifting but with the profile's position on the slope of the Kenya dome. The indications are that there is a relatively abrupt change to a 20-km Moho depth near the Lake Turkana Central shotpoint. This change to a mid-rift crustal thickness occurs not at the postulated margin at the southeastern shore of Lake Turkana but at least 50 km further to the northwest. We suggest that the position of this margin may need to be redefined. The P n velocity is quite high at 8.1 km/s. This may indicate either a cold upper mantle or anisotropy. An upper-mantle reflector has been identified between 15 and 20 km below the Moho. It dips gently away from the rift.

  14. Mechanism of crustal extension in the Laxmi Basin, Arabian Sea

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    Anju Pandey

    2015-11-01

    Full Text Available Continental rifting and magmatism has been extensively studied worldwide as it is believed that continental rifting, break up of continents and associated magmatism lead to genesis of new oceanic crust. However, various regions of the world show that these processes may lead to genesis of other types of crust than the oceanic crust. Laxmi Basin in the western continental margin of the India is one such region with an enigmatic crust. Due to its extreme strategic significance for the palaeogeographic reconstruction of continents during Cretaceous continental breakup of India, this basin has attracted various workers for more than two decades. However, still the issue of nature of crust in the basin remains controversial. In this contribution, in order to identify nature of crust, mechanism of continental extension in the Laxmi Basin has been studied for the first time through newly acquired seismic data from the basin. Here, we propose a plausible mechanism of crustal extension in the Laxmi Basin which eventually constrains the nature of crust of the Laxmi Basin. We have demonstrated that the crust in the Laxmi Basin can be categorised in two zones of stretched and transitional crust. In the stretched zone several fault bounded horst and graben structures are identified which preserve syn- and post-rift sediments along with different periods of hiatus in sedimentations as unconformities. These faults are identified as listric faults in the upper crust which sole out in the detachment faults. Detachment faults decouples the upper brittle and lower ductile crust. The transitional crust is identified as heavily intruded by sills and basaltic volcanic which were emplaced due to melting of subcontinental mantle (SCM after hyper-stretching of crust and serpentinisation of the SCM. Panikkar Ridge is proposed to be one such basaltic volcanic body derived from melting of lower part of the SCM.

  15. INVESTIGATION OF CRUSTAL MOTION IN THE TIEN SHAN USING INSAR

    Energy Technology Data Exchange (ETDEWEB)

    Mellors, R J

    2011-02-25

    The northern Tien Shan of Central Asia is an area of active mid-continent deformation. Although far from a plate boundary, this region has experienced 5 earthquakes larger than magnitude 7 in the past century and includes one event that may as be as large as Mw 8.0. Previous studies based on GPS measurements indicate on the order of 23 mm/yr of shortening across the entire Tien Shan and up to 15 mm/year in the northern Tien Shan (Figure 1). The seismic moment release rate appears comparable with the geodetic measured slip, at least to first order, suggesting that geodetic rates can be considered a proxy for accumulation rates of stress for seismic hazard estimation. Interferometric synthetic aperture radar may provide a means to make detailed spatial measurements and hence in identifying block boundaries and assisting in seismic hazard. Therefore, we hoped to define block boundaries by direct measurement and by identifying and resolving earthquake slip. Due to political instability in Kyrgzystan, the existing seismic network has not performed as well as required to precisely determine earthquake hypocenters in remote areas and hence InSAR is highly useful. In this paper we present the result of three earthquake studies and show that InSAR is useful for refining locations of teleseismically located earthquakes. ALOS PALSAR data is used to investigate crustal motion in the Tien Shan mountains of Central Asia. As part of the work, considerable software development was undertaken to process PALSAR data. This software has been made freely available. Two damaging earthquakes have been imaged in the Tien Shan and the locations provided by ALOS InSAR have helped to refine seismological velocity models. A third earthquake south of Kyrgyzstan was also imaged. The use of InSAR data and especially L band is therefore very useful in providing groundtruth for earthquake locations.

  16. New Crustal Stress Map of the Mediterranean and Central Europe

    Science.gov (United States)

    Heidbach, Oliver; Custodio, Susana; Kingdon, Andrew; Mariucci, Maria Teresa; Montone, Paola; Müller, Birgit; Pierdominicini, Simona; Rajabi, Mojtaba; Reinecker, John; Reiter, Karsten; Tingay, Mark; Williams, John; Ziegler, Moritz

    2016-04-01

    The World Stress Map (WSM) Project was initiated in 1986 under the auspices of the International Lithosphere Program in order to compile globally the information on the contemporary crustal stress state. For the 30th anniversary the WSM database has been updated and increased the number of data records from 21,750 to 42,410 worldwide. For the Mediterranean and Central European stress map the number of data records has increased from 3877 to 8192. The data come from a wide range of stress indicators such as borehole data (e.g. hydraulic fracturing, drilling induced tensile fractures, borehole breakouts), earthquake focal mechanism solutions and stress inversions from these, engineering methods (overcoring, borehole slotter) and geological data (e.g. volcanic alignment, inversion of fault slip data). To guarantee the comparability of the different stress indicator the resulting data are quality-ranked using the WSM quality ranking scheme. The new data set has a better coverage and enables us to identifying the regional and local variability of the stress pattern. For the Mediterranean and Central Europe we analysed the wave-length of the stress pattern by determining the mean orientation of the maximum horizontal stress SHmax on a regular grid using an updated version of the hybrid approach of Heidbach et al. [2010]. The preliminary results show that the Africa-Eurasia plate convergence is a key control of the overall stress pattern. However, given the complex tectonic setting in particular due to the indentation/collision of the Adriatic micro block, the Alpine topography as well as forces that control the movement of the Anatolian and Aegean block, the stress pattern shows in these regions significant changes in the mean SHmax orientation as well as in the tectonic regime.

  17. Shallow Crustal Thermal Structures of Central Taiwan Foothills Region

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    Shao-Kai Wu

    2013-01-01

    Full Text Available Crustal thermal structures are closely related to metamorphism, rock rheology, exhumation processes, hydrocarbon maturation levels, frictional faulting and other processes. Drilling is the most direct way to access the temperature fields in the shallow crust. However, a regional drilling program for geological investigation is usually very expensive. Recently, a large-scale in-situ investigation program in the Western Foothills of Central Taiwan was carried out, providing a rare opportunity to conduct heat flow measurements in this region where there are debates as to whether previous measured heat flows are representative of the thermal state in this region. We successfully collected 28 geothermal gradients from these wells and converted them into heat flows. The new heat flow dataset is consistent with previous heat flows, which shows that the thermal structures of Central Taiwan are different from that of other subduction accretionary prisms. We then combine all the available heat flow information to analyze the frictional parameters of the Chelungpu fault zone that ruptured during the 1999, Chi-Chi, Taiwan, earthquake. The heat flow dataset gave consistent results compared with the frictional parameters derived from another independent study that used cores recovered from the Chelungpu fault zone at depth. This study also shows that it is suitable for using heat-flow data obtained from shallow subsurface to constrain thrusting faulting parameters, similar to what had been done for the strike-slip San Andreas Fault in California. Additional fieldworks are planned to study heat flows in other mountainous regions of Taiwan for more advanced geodynamic modeling efforts.

  18. Crustal anisotropy contribution under-evaluated under Tibet ?

    Science.gov (United States)

    Herquel, G.; Edme, P.

    2003-04-01

    Moho P-to-S converted phases may be used to determine the complete crustal component of anisotropy. Phases with a good signal-to-noise ratio and with sufficient azimuthal coverage are required to avoid misleading results. Previous results may be low estimates of this contribution in Tibet (0.15-0.3s) since some very large mantellic delays have been observed in other areas of the plateau. New measurements use data from stations with the largest mantellic delays δt observed in Tibet: at least 2 seconds (stations ST17, ST18 and ST19 from Indepth III and BUDO). As the data for station BUDO was good enough , we compare results obtained by original signals and by single receiver functions obtained in the frequency domain or by iterative deconvolution. The data were processed using waveform rotation-correlation, tangential energy minimization and particle motion analysis methods. The results are remarkably coherent concerning the fast polarization direction and the mean delay value using these different techniques. Using receiver function stacked data in different bins of backazimuth we obtained delay values in good agreement with the other techniques and hence the processing can be accelerated using this approach. At all 4 stations a mean value of delay of 0.15s is retrieved with an uncertainty of 0.05s: no single value exceed 0.3s. These new results are similar to the first estimations in Tibet and confirm the results obtained in other aeras (Ural Montains, New Zealand and Basin and Range). Finally, we observe also a good correlation with the fast polarization direction obtained by teleseismic shear wave analysis.

  19. Evaluating Crustal Contamination Effects on the Lithophile Trace Element Budget of Shergottites

    Science.gov (United States)

    Brandon, A. D.; Ferdous, J.; Peslier, A. H.

    2017-01-01

    The origin of the incompatible trace element (ITE) enriched compositions of shergottites has been a point of contention for decades [1-2]. Two scenarios have been proposed, the first is that enriched shergottite compositions reflect an ITE-enriched mantle source, whereas in the second, the ITE enrichment reflects crustal contamination of mantle-derived parent magmas. Evidence supporting the first scenario is that the ITE-enriched shergottite compositions are consistent with the outcomes of magma ocean crystallization [3], and that Os-Nd isotope relationships for shergottites cannot be explained by realistic crustal contamination models [4]. In contrast, Cl and S isotopes are consistent with shergottite magmas interacting with Mars crust [5,6], and ITE-enriched olivine-hosted melt inclusions and interstitial glass are found in depleted shergottite Yamato 980459 [7]. These findings indicate that some level of crustal interaction occurred but the question of whether ITE-enrichments in some bulk shergottites reflect crustal contamination remains open. Recently, a Mars crustal breccia meteorite has been found, NWA 7034 and its paired stones, that is our best analogue to an average of Mars ancient crust [8-10]. This allows for better constraints on crustal contamination of shergottite magmas. We modeled magma-crust mixing and assimilation-fractional crystallization (AFC) using ITE-depleted shergottite compositions and bulk NWA 7034 and its clasts as end-members. The results of these models indicate that crustal contamination can only explain the ITE-enriched compositions of some bulk shergottites under unusual circumstances. It is thus likely that the shergottite range of compositions reflects primarily mantle sources.

  20. Crustal-scale magmatism and its control on the longevity of magmatic systems

    Science.gov (United States)

    Karakas, Ozge; Degruyter, Wim; Bachmann, Olivier; Dufek, Josef

    2017-04-01

    Constraining the duration and evolution of crustal magma reservoirs is crucial to our understanding of the eruptive potential of magmatic systems, as well as the volcanic:plutonic ratios in the crust, but estimates of such parameters vary widely in the current literature. Although no consensus has been reached on the lifetime of magma reservoirs, recent studies have revealed about the presence, location, and melt fraction of multi-level (polybaric) storage zones in the crust. If magma accumulates at different crustal levels, it must redistribute significant enthalpy within the crustal column and therefore must influence the lifetime of magma plumbing systems. However, an evaluation of the mass and heat budget of the entire crustal column is lacking. Here, we use a two-dimensional thermal model to determine the thermal conditions under which both lower and upper crustal magma bodies form. We find that large lower crustal mush zones supply heat to the upper crust and reduce the amount of thermal energy necessary to form subvolcanic reservoirs. This indicates that the crust is thermally viable to sustain partially molten magma reservoirs over long timescales (>10^5-106 yr) for a range of magma fluxes (10^-4 to 10^-2 km^3/yr). Our results reconcile physical models of crustal magma evolution and field-based estimates of intrusion rates in numerous magmatic provinces (which include both volcanic and plutonic lithologies). We also show that young magmatic provinces ( 106 yr) can accumulate magma and build reservoirs capable of triggering supereruptions, even with intrusion rates as low as ≤10^-2 km^3/yr. Hence, the total duration of magmatism is critical in determining the size of the magma reservoirs, and should be combined with the magma intrusions rates to assess the capability of volcanic systems to form the largest eruptions on Earth.

  1. Numerical simulations of an ocean/continent convergent system: influence of subduction geometry and mantle wedge hydration on crustal recycling

    CERN Document Server

    Roda, Manuel; Spalla, Maria Iole; 10.1029/2009GC003015

    2011-01-01

    The effects of the hydration mechanism on continental crust recycling are analyzed through a 2D finite element thermo-mechanical model. Oceanic slab dehydration and consequent mantle wedge hydration are implemented using a dynamic method. Hydration is accomplished by lawsonite and serpentine breakdown; topography is treated as a free surface. Subduction rates of 1, 3, 5, 7.5 and 10 cm/y, slab angles of 30o, 45o and 60o and a mantle rheology represented by dry dunite and dry olivine flow laws, have been taken into account during successive numerical experiments. Model predictions pointed out that a direct relationship exists between mantle rheology and the amount of recycled crustal material: the larger the viscosity contrast between hydrated and dry mantle, the larger the percentage of recycled material into the mantle wedge. Slab dip variation has a moderate impact on the recycling. Metamorphic evolution of recycled material is influenced by subduction style. TPmax, generally representative of eclogite facie...

  2. A unified analysis of crustal motion in Southern California, 1970-2004: The SCEC crustal motion map

    Science.gov (United States)

    Shen, Z.-K.; King, R. W.; Agnew, D. C.; Wang, M.; Herring, T. A.; Dong, D.; Fang, P.

    2011-11-01

    To determine crustal motions in and around southern California, we have processed and combined trilateration data collected from 1970 to 1992, VLBI data from 1979 to 1992, and GPS data from 1986 to 2004: a long temporal coverage required in part by the occurrence of several large earthquakes in this region. From a series of solutions for station positions, we have estimated interseismic velocities, coseismic displacements, and postseismic motions. Within the region from 31°N to 38°N. and east to 114°W, the final product includes estimated horizontal velocities for 1009 GPS, 190 trilateration, and 16 VLBI points, with ties between some of these used to stabilize the solution. All motions are relative to the Stable North American Reference Frame (SNARF) as realized through the velocities of 20 GPS stations. This provides a relatively dense set of horizontal velocity estimates, with well-tested errors, for the past quarter century over the plate boundary from 31°N to 36.5°N. These velocities agree well with those from the Plate Boundary Observatory, which apply to a later time period. We also estimated vertical velocities, 533 of which have errors below 2 mm/yr. Most of these velocities are less than 1 mm/yr, but they show 2-4 mm/yr subsidence in the Ventura and Los Angeles basins and in the Salton Trough. Our analysis also included estimates of coseismic and postseismic motions related to the 1992 Landers, 1994 Northridge, 1999 Hector Mine, and 2003 San Simeon earthquakes. Postseismic motions increase logarithmically over time with a time constant of about 10 days, and generally mimic the direction and relative amplitude of the coseismic offsets.

  3. Density heterogeneity of the upper mantle beneath Siberia from satellite gravity and a new regional crustal model

    DEFF Research Database (Denmark)

    Herceg, Matija; Thybo, Hans; Artemieva, Irina

    2013-01-01

    We present a new regional model for the density structure of the upper mantle below Siberia. The residual mantle gravity anomalies are based on gravity data derived from the GOCE gravity gradients and geopotential models, with crustal correction to the gravity field being calculated from a new...... on regional and global crustal models. We analyze how uncertainties and errors in the crustal model propagate from crustal densities to mantle residual gravity anomalies and the density model of the upper mantle. The new regional density model for the Siberian craton and the West Siberian Basin complements...

  4. New insights on the crustal thickness and its lateral variations beneath the Rif Cordillera

    Science.gov (United States)

    Gil de la Iglesia, A.; Diaz Cusi, J.; Gallart, J.; Carbonell, R.; Harnafi, M.; Levander, A.

    2014-12-01

    The Rif cordillera forms, together with the Betic ranges, one of the tightest orogenic arcs on Earth. This continental boundary zone is dominated now by the slow convergence between Nubia and Eurasia, but with clear evidences of extensional tectonics. One of the missing elements to constrain the complex geodynamics of the Gibraltar Arc System is the knowledge on crustal structure beneath northern Morocco. In the last decade a major effort has been done in this sense, from active and passive seismics. We compile here the recent results available from the Rif domains. Two 330 km long wide angle DSS profiles were recorded end of 2011 across the Rif in NS and EW transects within the Rifsis project, complemented by onshore recordings of the Gassis-WestMed marine profiles. At the same period, BB seismic arrays were deployed in the area within Topo-Iberia and Picasso projects, allowing receiver function analyses of crustal depths. The ray-tracing modeling of the Rifsis profiles reveal a large Moho step and an area of crustal thickening both in EW and NS directions, grossly coincident with the Bouguer gravity anomalies. The deployment logistics allowed that all the stations recorded all the shots, thus providing useful offline data. We will use here all available in-line and offline data to provide a map of the crustal thickness in northern Morocco. We combined two approaches: i) a hyperbolic time reduction applied to the seismic data, resulting in low-fold stacks in which the reflections from the Moho should appear as subhorizontal lines; ii) the arrival times of the observed PmP phases allow, assuming a mean crustal velocity, to assign a midpoint crustal thickness to each lecture. Although some uncertainties may be inherent to those approaches, a large crustal root, reaching more than 50 km, is well documented in the central part of the Rif Cordillera, close to the zone where the Alboran slab may still be attached to the lithosphere. We also compared these results with

  5. Crustal structure of the western Indian shield: Model based on regional gravity and magnetic data

    Directory of Open Access Journals (Sweden)

    Suman Kilaru

    2013-11-01

    This study probes the geometry of the different crustal units in terms of density and susceptibility variations in order to decipher the imprints of the major tectonic processes the region has undergone. In order to decipher the crustal geometry of the Gadra–Fatehpur profile, two NW–SE gravity and magnetic profile vertical sections (A–A′ in the south and B–B′ in the north are modelled on the basis of the constraints provided from previous seismic models. The crustal model of the Gadra–Fatehpur profile is composed of alluvium, Tertiary sediments, MIS, Marwar Supergroup, low-density layers (LDLs and the middle–lower crustal layers, with a distinct change in configuration from the southwest to northeast. The Moho dips from SW to NE, the MIS in the SW gives way to the thick pile of the Marwar Supergroup to the NE. The evolution of MIS has been suggested to have occurred as a consequence of delamination of the upper mantle. LDLs are incorporated in Gadra–Fatehpur model. In the SW, LDL (2550 kg/m3 lies below the MIS in the NE, another LDL (2604 kg/m3 is depicted below the mid-crustal layer.

  6. Contemporary crustal movement of southeastern Tibet: Constraints from dense GPS measurements

    Science.gov (United States)

    Pan, Yuanjin; Shen, Wen-Bin

    2017-03-01

    The ongoing collision between the Indian plate and the Eurasian plate brings up N-S crustal shortening and thickening of the Tibet Plateau, but its dynamic mechanisms remain controversial yet. As one of the most tectonically active regions of the world, South-Eastern Tibet (SET) has been greatly paid attention to by many geoscientists. Here we present the latest three-dimensional GPS velocity field to constrain the present-day tectonic process of SET, which may highlight the complex vertical crustal deformation. Improved data processing strategies are adopted to enhance the strain patterns throughout SET. The crustal uplifting and subsidence are dominated by regional deep tectonic dynamic processes. Results show that the Gongga Shan is uplifting with 1-1.5 mm/yr. Nevertheless, an anomalous crustal uplifting of ~8.7 mm/yr and negative horizontal dilation rates of 40-50 nstrain/yr throughout the Longmenshan structure reveal that this structure is caused by the intracontinental subduction of the Yangtze Craton. The Xianshuihe-Xiaojiang fault is a major active sinistral strike-slip fault which strikes essentially and consistently with the maximum shear strain rates. These observations suggest that the upper crustal deformation is closely related with the regulation and coupling of deep material.

  7. Crustal moment of inertia of glitching pulsars with the KDE0v1 Skyrme interaction

    Energy Technology Data Exchange (ETDEWEB)

    Madhuri, K.; Routray, T.R.; Pattnaik, S.P. [Sambalpur University, School of Physics, Jyotivihar (India); Basu, D.N. [Variable Energy Cyclotron Center, Kolkata (India)

    2017-07-15

    The mass, radius and crustal fraction of moment of inertia in neutron stars are calculated using β-equilibrated nuclear matter obtained from the Skyrme effective interaction. The transition density, pressure and proton fraction at the inner edge separating the liquid core from the solid crust of the neutron stars are determined from the thermodynamic stability conditions using the KDE0v1 set. The neutron star masses obtained by solving the Tolman-Oppenheimer-Volkoff equations using neutron star matter obtained from this set are able to describe highly massive compact stars ∝ 2M {sub CircleDot}. The crustal fraction of the moment of inertia can be extracted from studying pulsar glitches. This fraction is highly dependent on the core-crust transition pressure and corresponding density. These results for pressure and density at core-crust transition together with the observed minimum crustal fraction of the total moment of inertia provide a limit for the radius of the Vela pulsar, R ≥ 3.69 + 3.44M/M {sub CircleDot}. Present calculations suggest that the crustal fraction of the total moment of inertia can be ∝ 6.3% due to crustal entrainment caused by the Bragg reflection of unbound neutrons by lattice ions. (orig.)

  8. Qinghai-Tibet Plateau crustal thickness derived from EGM2008 and CRSUT2.0

    Directory of Open Access Journals (Sweden)

    Zhou Hao

    2014-11-01

    Full Text Available Qinghai-Tibet Plateau is the most complex region for crustal thickness inversion, while high-resolution earth gravity model (EGM makes it possible to obtain high precision gravity anomaly, which is a key parameter to depict the Earth’s inner structure in geodesy domain. On the basis of this principle, we calculated the Bouguer gravity anomalies in Qinghai-Tibet Plateau with EGM2008 and SRTM6. 0 by efficient high-degree spherical harmonic synthesis algorithm. In order to obtain the gravity anomaly caused by Moho density mutant, the noises caused by the topography was removed by wavelet details. Then, the crustal thickness was corrected on the basis of CRUST 2. 0 with the deep-large-scale single density interface formula. The inversion result indicates that the crustal thickness in Qinghai-Tibet Plateau is between 50 km and 75 km, which is in correspondence with the recent science research result. Compared with the 2 degree CRUST 2. 0 model, the spatial resolution of crustal thickness in our research can reach 40 arc minutes. In addition, there is a positive relationship between the inversed crustal thickness and topography, which can prove the effectiveness of Airy-Heiskanen isostatic model in gravity reduction.

  9. Lifetime and size of shallow magma bodies controlled by crustal-scale magmatism

    Science.gov (United States)

    Karakas, Ozge; Degruyter, Wim; Bachmann, Olivier; Dufek, Josef

    2017-06-01

    Magmatic processes on Earth govern the mass, energy and chemical transfer between the mantle, crust and atmosphere. To understand magma storage conditions in the crust that ultimately control volcanic activity and growth of continents, an evaluation of the mass and heat budget of the entire crustal column during magmatic episodes is essential. Here we use a numerical model to constrain the physical conditions under which both lower and upper crustal magma bodies form. We find that over long durations of intrusions (greater than 105 to 106 yr), extensive lower crustal mush zones develop, which modify the thermal budget of the upper crust and reduce the flux of magma required to sustain upper crustal magma reservoirs. Our results reconcile physical models of magma reservoir construction and field-based estimates of intrusion rates in numerous volcanic and plutonic localities. Young igneous provinces (less than a few hundred thousand years old) are unlikely to support large upper crustal reservoirs, whereas longer-lived systems (active for longer than 1 million years) can accumulate magma and build reservoirs capable of producing super-eruptions, even with intrusion rates smaller than 10-3 to 10-2 km3 yr-1. Hence, total duration of magmatism should be combined with the magma intrusion rates to assess the capability of volcanic systems to form the largest explosive eruptions on Earth.

  10. Crustal Structure around Ordos Terrain Derived from Ambient Noise Tomography

    Science.gov (United States)

    Liu, J.; Ning, J.; Tang, Y.; Chen, Y. J.

    2011-12-01

    We performed Rayleigh wave tomography around Ordos terrain by applying the ambient noise method to broadband seismic data. The data was recorded at 85 temporary stations of PKU array operated along Yinchuan-Jinan and 410 permanent stations of CEA network operated between Eastern margin of Tibetan plateau and Huabei basin. Receiver function technique was also applied to study Moho discontinuity in Southern Ordos by PKU array. We developed a new stacking technique to obtain high-quality dispersion curves of Rayleigh waves from cross correlation of seismic ambient noise. This technique is based on phase-matched filter and was implemented in a four-step iterative process: signal compression, stacking, signal extraction and signal decompression. We stack all the compressed Estimated Green Functions that have almost the same path to improve signal to noise ratio. Results show that this new stacking method is stable and can improve the quality of ambient noise inversion. The inversion results present in this study are consistent with tectonic nature in this region. S velocity at depths of 0-10 km beneath Huabei plain, Sichuan basin and Ordos terrain are obviously lower than those beneath Eastern margin of Tibetan plateau. That is probably due to the thick sediments in Huabei plain, Sichuan basin and Ordos block. S velocity beneath Lvliang-Taihang region keeps high in whole crust and this may relate to Cenozoic intrusion of mantle material here. Our results revealed that the crust is thick in the southern part of the Ordos terrain while it is a little thin in the northern part. This confirmed the result given by Chen et al. (2010) and explained the contradiction between the work of Chen's and former results. The contrasting crustal thickness of the Ordos terrain is also in accord with our Receiver Function results. Receiver functions revealed two interfaces at about 40 km and 60 km in southern part of the Ordos terrain, comparing with only one located at about 40 km depth

  11. A hemispherical dynamo model: Implications for the Martian crustal magnetization

    Science.gov (United States)

    Dietrich, W.; Wicht, J.; Christensen, U. R.

    2011-12-01

    In 1999 the Mars Global Surveyor detected a strong but very heterogeneous crustal magnetization mainly localized in the southern hemisphere. Their magnetization dichotomy may have either an external or an internal origin. In the first scenario, the Martian crust was fully magnetized by a dipolar dynamo induced in the Martian liquid core. After the core dynamo cessation, the crust was demagnetized by volcanoes, impacts or any other resurfacing event distributed not homogeneously over the surface. The internal origin, which is investigated here, relies on a per se hemispherical internal magnetric field. For this, we rely on that Mars never developed an inner core. The planets ancient dynamo was thus exclusively driven by secular cooling and radiogenic heating. Due to the small planetary size, the core mantle boundary (CMB) heat flux may be not as homogeneous, as in e.g. Earth. Mantle convection in smaller planets is thought to develope larger scales, maybe even a huge single-plume structure. Giant impacts might have played a crucial role in the thermal history of Mars, hence they are heating mainly one hemisphere. Giant plumes and major impact events would both cause a hemispherical CMB heat flux pattern. Therefore, we model the ancient Martian dynamo as rotating, convecting and conducting fluid heated by an internal heat source and contained in a spherical shell, where the CMB heat flux is perturbed by a sinusoidal anomaly. Compared to the classical columnar convection, we find a drastically different flow pattern. There meridional circulation seeking to equilibrate the heat difference between both hemispheres is diverted into two counterdirected cells of axisymmetric zonal flows (thermal winds) by the strong Coriolis force. Convective plumes are confined to the region of high heat flux in the vicinity of the southern pole. Core convection is thus dominated by equatorially antisymmetric and axisymmetric (EAA) modes. In the columnar regime, poloidal and toroidal

  12. Crustal evolution of South American Platform based on Sm-Nd isotope geochemistry; Evolucao crustal da plataforma sul americana com base na geoquimica isotopica Sm-Nd

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Kei

    1998-07-01

    Sm-Nd isotopic systematics is relevant to the topics of origin and evolution the of continental crust, where model ages refer to the time when crustal material was differentiated from the upper mantle. Alternative interpretations are due to a lack of adequate information on crustal processes and the variable composition of the mantle sources. The Sm-Nd methods are presented, and applied on rock materials from the South American Platform. The main conclusions indicate juvenile accretion with higher growth rates (peaks), around 3.7-3.5 Ga ({approx} 0.5% in volume), 3.1 - 2.9 Ga ({approx}16%), 2.7 - 2.6 ({approx} 9%), 2.2 - 1.9 (35%) and 1.3-1.0 (7%). The continental growth curve indicates that about 35 % of the crust was formed by 2.5 Ga, 88% by 1.8 Ga and 99% by 1.0 Ga, and the remaining {approx} 1 % was added in the Phanerozoic. Rapid crustal growth occurred between 2.2 and 1.9 Ga. The main period of continental crust formation occurred during the Paleoproterozoic, corresponding to 54 % in volume. Sm-Nd model ages, when compared with the crystallisation ages of granitoid rocks, furnish a rough estimate of juvenile vs. reworked material. Within the South American Platform about 45% of juvenile continental crust is still preserved within tectonic provinces of different ages. The remainder represents continental crust reworked in younger tectono-thermal events. In particular crustal reworking was predominating over juvenile accretion during Meso-Neoproterozoic. The Transbrasiliano Lineament is a megasuture, active in the Neoproterozoic, which separates a large northwestern mass, including the Amazonian and Sao Luis Cratons, from a southeastern mass, formed by a collage of cratonic fragments, of which the Sao Francisco and Rio de La Plata are the largest. The crustal evolutions of these two large continental masses are considered individually, and can be resumed following form: I - Old Archean rocks (>3.4 Ga) are found only within the south-eastern part (Gaviao Block

  13. Crustal Anisotropy Beneath the Western Segment of North Anatolian Fault Zone from Local Shear-Wave Splitting

    Science.gov (United States)

    Altuncu Poyraz, S.; Teoman, U.; Kahraman, M.; Turkelli, N.; Rost, S.; Thompson, D. A.; Houseman, G.

    2014-12-01

    Shear-wave splitting from local earthquakes provides valuable knowledge on anisotropy of the upper crust. Upper-crustal anisotropy is widely interpreted as due to aligned fluid-filled cracks or pores. Differential stress is thought to close cracks aligned perpendicular to the maximum principal stress and leaves cracks open that are aligned perpendicular to the minimum horizontal compressional stress. In other cases local shear-wave splitting has been found to be aligned with regional faulting. Temporal variations in local splitting patterns might provide hints of changes in stress orientation related to earthquakes or volcanoes. North Anatolian Fault Zone (NAFZ) is a large-scale continental strike slip fault system originating at the Karlıova Junction in the east where it intersects the East Anatolian Fault (EAF) and extends west cutting across the entire Northern Turkey towards the Aegean Sea and the mainland Greece. Our primary focus is to provide constraints on the crustal anisotropy beneath the western segment of the North Anatolian Fault Zone with the use of a data set collected from a dense temporary seismic network consisting of 70 stations that was deployed in early May 2012 and operated for 18 months in the Sakarya region and the surroundings during the Faultlab experiment. For the local shear wave splitting analysis, out of 1344 events, we extracted 90 well located earthquakes with magnitudes greater than 2.0. Local shear-wave splitting makes use of earthquakes close to and nearly directly below the recording station. Incidence angles of less than 45 degrees were used to avoid the free-surface effect and resulting non-linear particle motion. Basically, two essential parameters for each station-event pair is needed for shear wave splitting calculations. One of them is fast polarization direction (ɸ) and the other is delay time (δt) between the fast and slow components of the shear wave. In this study, delay times vary between 0,02 and 0,25 seconds

  14. Optical focusing through biological tissue and tissue-mimicking phantoms up to 9.6 centimeters thick with digital optical phase conjugation

    Science.gov (United States)

    Shen, Yuecheng; Liu, Yan; Ma, Cheng; Wang, Lihong V.

    2017-02-01

    Optical phase conjugation (OPC) based wavefront shaping techniques focus light through or within scattering media, which is critically important for deep-tissue optical imaging, manipulation, and therapy. However, to date, the sample thicknesses used in wavefront shaping experiments have been limited to only a few millimeters or several transport mean free paths. Here, by using a long-coherence-length laser and an optimized digital OPC system that efficiently delivers light power, we focused 532 nm light through tissue-mimicking phantoms up to 9.6 cm thick, as well as through ex vivo chicken breast tissue up to 2.5 cm thick.

  15. Polymerization of a divalent/tetravalent metal-storing atom-mimicking dendrimer.

    Science.gov (United States)

    Albrecht, Ken; Hirabayashi, Yuki; Otake, Masaya; Mendori, Shin; Tobari, Yuta; Azuma, Yasuo; Majima, Yutaka; Yamamoto, Kimihisa

    2016-12-01

    The phenylazomethine dendrimer (DPA) has a layer-by-layer electron density gradient that is an analog of the Bohr atom (atom mimicry). In combination with electron pair mimicry, the polymerization of this atom-mimicking dendrimer was achieved. The valency of the mimicked atom was controlled by changing the chemical structure of the dendrimer. By mimicking a divalent atom, a one-dimensional (1D) polymer was obtained, and by using a planar tetravalent atom mimic, a 2D polymer was obtained. These poly(dendrimer) polymers could store Lewis acids (SnCl2) in their unoccupied orbitals, thus indicating that these poly(dendrimer) polymers consist of a series of nanocontainers.

  16. A Reinvestigation of Crustal Thickness in the Tibetan Plateau Using Absolute Gravity, GPS and GRACE Data

    Directory of Open Access Journals (Sweden)

    Wenke Sun

    2011-01-01

    Full Text Available The geodetic evidence of the uplift and crustal thickness of the Tibetan Plateau has been presented for the first time (Sun et al. 2009 using gravity and GPS observations. In this paper, we reinvestigate this tectonic deformation in more detail using GRACE data and taking the GIA effect into account. We first summarize the previous gravity and GPS observations and a local gravity network in the Dali County. The comparison between the surface absolute gravity and space GRACE gravity measurements shows that they are harmonic, agree well. Finally, we assume that the residual gravity change reflects material transport accompanying vertical movements on the crustal bottom; the crustal thickening rate is inferred as 1.9 ¡_ 1.4 cm yr-1. As the crust thickens, the mass of a column of rock beneath the station decreases because mantle is displaced by crust, causing a reduction in gravity.

  17. Structural and Geologic Mapping of Southern Tellus Regio, Venus: Implications for Crustal Plateau Formation

    Science.gov (United States)

    Graupner, Melanie

    2013-03-01

    Crustal plateau formation on Venus is subject to animated debate, centered on plateau support and resulting surface deformation. Detailed mapping provides critical clues for plateau evolution. Southern Tellus Regio records broadly synchronous formation of contractional and extensional structures, accompanied by deposition of flood material. Short-wavelength folds occur across the entire plateau, the extent of which has previously been undocumented. Generally the early-formed structures record a high structural fluidity, marked by variable orientation of structures or juxtaposition of neighboring structural suites. This interpretation of the geologic history of the region indicates the necessity of an extremely high geothermal gradient and provides a means to evaluate the different crustal plateau hypotheses. The mantle downwelling, mantle upwelling, and pulsating continents hypotheses fail to accommodate the surface features recorded in this study. However, the lava pond hypothesis provides a suitable hypothesis of crustal plateau formation that accommodates structural elements recorded in this study.

  18. Fast crustal deformation computing method for multiple computations accelerated by a graphics processing unit cluster

    Science.gov (United States)

    Yamaguchi, Takuma; Ichimura, Tsuyoshi; Yagi, Yuji; Agata, Ryoichiro; Hori, Takane; Hori, Muneo

    2017-08-01

    As high-resolution observational data become more common, the demand for numerical simulations of crustal deformation using 3-D high-fidelity modelling is increasing. To increase the efficiency of performing numerical simulations with high computation costs, we developed a fast solver using heterogeneous computing, with graphics processing units (GPUs) and central processing units, and then used the solver in crustal deformation computations. The solver was based on an iterative solver and was devised so that a large proportion of the computation was calculated more quickly using GPUs. To confirm the utility of the proposed solver, we demonstrated a numerical simulation of the coseismic slip distribution estimation, which requires 360 000 crustal deformation computations with 82 196 106 degrees of freedom.

  19. On the precursors to the 2011 Tohoku earthquake: crustal movements and electromagnetic signatures

    Directory of Open Access Journals (Sweden)

    Makoto Kamiyama

    2016-03-01

    Full Text Available We compare the precursory behaviour of crustal movements with electromagnetic signatures for the 2011 off the Pacific Coast of Tohoku earthquake. First, we present the Global Positioning System (GPS data on the co-seismic variations and pre-seismic precursors (medium-term, short-term and imminent precursors. Then, we will review recently published results on electromagnetic precursors, including mainly short-term subionospheric very low frequency (VLF/LF propagation anomaly, ultralow frequency (ULF magnetic field depression and ULF/extremely low frequency (ELF atmospheric radiation. Finally, we examine the relationship between the crustal movements and electromagnetic phenomena. We conclude that at least short-term electromagnetic precursors are closely correlated in time with the corresponding crustal movements. This seems to provide evidence on the link between lithospheric and electromagnetic processes. Some discussions will be given on the possible mechanism of this link.

  20. Crustal imaging of the Northwest Himalaya and its foredeep region from teleseismic events

    Directory of Open Access Journals (Sweden)

    Sowrav Saikia

    2016-07-01

    Full Text Available Over 450 receiver functions from 8 broadband stations located in the Indo-Gangetic plain and Northwest Himalayan region are analyzed to examine the crustal properties across the contiguous region. We identified the P-to-S phase beneath each station and estimated the crustal thickness from time delay of this phase with respect to the direct P arrival. With the help of the slant stacking technique, we determined bulk crustal chemical properties and validated our estimate of crustal thickness. The Moho was encountered in the Indo-Gangetic plain at an average depth of 33 km and thickened towards the Northwest Himalaya with the Moho depth varying from 37 to 52 km. The thickest crust matched the highest topography, which is strong evidence of the occurrence of a crustal root of the mountain range. The time domain iterative linearized inversion technique is used to invert radial receiver functions to wave velocity structures for both tectonic regimes. From the forward modelling, we found mid-crustal low-velocity layers at different patches at a depth of 10–30 km in the Northwest Himalaya region. The presence of melts may be inferred in the mid crust with high values of Poisson ratio (σ ≥ 0.260 for the stations in the Northwest Himalaya. Towards south in the Indo-Gangetic alluvium plain, we estimated a medium to higher value of Poisson ratio (0.240 ≤ σ ≤ 0.290, but velocity modelling implies absence of an intracrustal low-velocity zone around the region.

  1. Crustal structure of north Peru from analysis of teleseismic receiver functions

    Science.gov (United States)

    Condori, Cristobal; França, George S.; Tavera, Hernando J.; Albuquerque, Diogo F.; Bishop, Brandon T.; Beck, Susan L.

    2017-07-01

    In this study, we present results from teleseismic receiver functions, in order to investigate the crustal thickness and Vp/Vs ratio beneath northern Peru. A total number of 981 receiver functions were analyzed, from data recorded by 28 broadband seismic stations from the Peruvian permanent seismic network, the regional temporary SisNort network and one CTBTO station. The Moho depth and average crustal Vp/Vs ratio were determined at each station using the H-k stacking technique to identify the arrival times of primary P to S conversion and crustal reverberations (PpPms, PpSs + PsPms). The results show that the Moho depth correlates well with the surface topography and varies significantly from west to east, showing a shallow depth of around 25 km near the coast, a maximum depth of 55-60 km beneath the Andean Cordillera, and a depth of 35-40 km further to the east in the Amazonian Basin. The bulk crustal Vp/Vs ratio ranges between 1.60 and 1.88 with the mean of 1.75. Higher values between 1.75 and 1.88 are found beneath the Eastern and Western Cordilleras, consistent with a mafic composition in the lower crust. In contrast values vary from 1.60 to 1.75 in the extreme flanks of the Eastern and Western Cordillera indicating a felsic composition. We find a positive relationship between crustal thickness, Vp/Vs ratio, the Bouguer anomaly, and topography. These results are consistent with previous studies in other parts of Peru (central and southern regions) and provide the first crustal thickness estimates for the high cordillera in northern Peru.

  2. Monitoring Vertical Crustal Deformation and Gravity Variations during Water Level Changes at the Three Gorges Reservoir

    Directory of Open Access Journals (Sweden)

    WANG Wei

    2017-06-01

    Full Text Available Monitoring vertical crustal deformation and gravity changes during water level changes at the Three Gorges reservoir is important for the safe operation of the Three Gorges Dam and for the monitoring and prevention of a regional geological disaster. In this study, we determined vertical crustal deformation and gravity changes during water level variations of the Three Gorges reservoir from direct calculations and actual measurements and a comprehensive solution. We used water areas extracted image data from the ZY-3 satellite and water level data to calculate gravity changes and vertical crustal deformation caused by every 5 m change in the water level due to storage and drainage of the Three Gorges reservoir from 145 m to 175 m. The vertical crustal deformation was up to 30 mm. The location of gravity change above 20 μ Gal(1 Gal=10-2 m/s2 was less than 2 km from the centerline of the Yangtze River. The CORS ES13 in Badong, near the reservoir, measured the vertical crustal deformation during water level changes. Because of the small number of CORS and gravity stations in the Three Gorges reservoir area, monitoring deformation and gravity related to changes in the Three Gorges reservoir water level cannot be closely followed. Using 26 CORS and some of the gravity stations in the Three Gorges area and based on loading deformation and the spherical harmonic analysis method, an integrated solution of vertical deformation and gravity variations during water level changes of the reservoir was determined, which is consistent with the actual CORS monitoring results. By comparison, we found that an integrated solution based on a CORS network can effectively enhance the capability of monitoring vertical crustal deformation and gravity changes during water level variations of the reservoir.

  3. P-wave receiver function study of crustal structure in Scandinavia

    Science.gov (United States)

    Makushkina, Anna; Thybo, Hans; Vinnik, Lev; Youssof, Mohammad

    2016-04-01

    In this study we present preliminary results on the structure of the continental crust in northern Scandinavia. The research area consists of three geologically different domains: the Archaean Domain in the north-east, the Palaeoproterozoic Svecofennian Domain in the east and the Caledonian Deformed Domain in the west (Gorbatschev and Bogdanova,1993). We present results based on data collected by 60 seismic stations during 2-4 years of deployment in the ScanArray experiment, which is an international collaboration between Scandinavian, German and British universities. We use the receiver function (RF) technique in the LQT ray-oriented coordinate system (Vinnik, 1977). Receiver function analysis has rather high vertical resolution of the depth to seismic discontinuities which cause transformation between P- and S-waves. The whole dataset is uniformly filtered and deconvolved records are stacked using appropriate moveout corrections. We have used events with a magnitude ≥ 5.5 Mw, with epicentral distances range from 30° to 95°. The technique allows us to constrain crustal structure and determine the Moho depth around stations by analyzing the PS converted phases generated at discontinuities in particular the Moho. We present preliminary interpretation of P-wave RF analysis in terms of the complex tectonic and geodynamic evolution of the Baltic Shield. Further studies will include joint P and S receiver function analysis of this area as well as investigations of the upper mantle. References: Vinnik L.P. (1977) Detection of waves converted from P to SV in the mantle. Phys. Earth planet. Inter. 15, 39-45 Gorbatschev R., Bogdanova, S. (1993) Frontiers in the Baltic Shield. Precambrian Res. 64, 3-21

  4. Upper-crustal structure of the inner Continental Borderland near Long Beach, California

    Science.gov (United States)

    Baher, S.; Fuis, G.; Sliter, R.; Normark, W.R.

    2005-01-01

    A new P-wave velocity/structural model for the inner Continental Borderland (ICB) region was developed for the area near Long Beach, California. It combines controlled-source seismic reflection and refraction data collected during the 1994 Los Angeles Region Seismic Experiment (LARSE), multichannel seismic reflection data collected by the U.S. Geological Survey (1998-2000), and nearshore borehole stratigraphy. Based on lateral velocity contrasts and stratigraphic variation determined from borehole data, we are able to locate major faults such as the Cabrillo, Palos Verdes, THUMS-Huntington Beach, and Newport Inglewood fault zones, along with minor faults such as the slope fault, Avalon knoll, and several other yet unnamed faults. Catalog seismicity (1975-2002) plotted on our preferred velocity/structural model shows recent seismicity is located on 16 out of our 24 faults, providing evidence for continuing concern with respect to the existing seismic-hazard estimates. Forward modeling of P-wave arrival times on the LARSE line 1 resulted in a four-layer model that better resolves the stratigraphy and geologic structures of the ICB and also provides tighter constraints on the upper-crustal velocity structure than previous modeling of the LARSE data. There is a correlation between the structural horizons identified in the reflection data with the velocity interfaces determined from forward modeling of refraction data. The strongest correlation is between the base of velocity layer 1 of the refraction model and the base of the planar sediment beneath the shelf and slope determined by the reflection model. Layers 2 and 3 of the velocity model loosely correlate with the diffractive crust layer, locally interpreted as Catalina Schist.

  5. Layered Crustal and Mantle Structure and Anisotropy beneath the Afar Depression and Malawi Rift Zone

    Science.gov (United States)

    Reed, Cory Alexander

    Although a wealth of geophysical data sets have been acquired within the vicinity of continental rift zones, the mechanisms responsible for the breakup of stable continental lithosphere are ambiguous. Eastern Africa is host to the largest contemporary rift zone on Earth, and is thus the most prominent site with which to investigate the processes which govern the rupture of continental lithosphere. The studies herein represent teleseismic analyses of the velocity and thermomechanical structure of the crust and mantle beneath the Afar Depression and Malawi Rift Zone (MRZ) of the East African Rift System. Within the Afar Depression, the first densely-spaced receiver function investigation of crustal thickness and inferred velocity attenuation across the Tendaho Graben is conducted, and the largest to-date study of the topography of the mantle transition zone (MTZ) beneath NE Africa is provided, which reveals low upper-mantle velocities beneath the Afar concordant with a probable mantle plume traversing the MTZ beneath the western Ethiopian Plateau. In the vicinity of the MRZ, a data set comprised of 35 seismic stations is employed that was deployed over a two year period from mid-2012 to mid-2014, belonging to the SAFARI (Seismic Arrays For African Rift Initiation) experiment. Accordingly, the first MTZ topography and shear wave splitting analyses were conducted in the region. The latter reveals largely plate motion-parallel anisotropy that is locally modulated by lithospheric thickness abnormalities adjacent to the MRZ, while the former reveals normal MTZ thicknesses and shallow discontinuities that support the presence of a thick lithospheric keel within the MRZ region. These evidences strongly argue for the evolution of the MRZ via passive rifting mechanisms absent lower-mantle influences.

  6. Electrocardiogram artifact caused by rigors mimicking narrow complex tachycardia: a case report.

    Science.gov (United States)

    Matthias, Anne Thushara; Indrakumar, Jegarajah

    2014-02-04

    The electrocardiogram (ECG) is useful in the diagnosis of cardiac and non-cardiac conditions. Rigors due to shivering can cause electrocardiogram artifacts mimicking various cardiac rhythm abnormalities. We describe an 80-year-old Sri Lankan man with an abnormal electrocardiogram mimicking narrow complex tachycardia during the immediate post-operative period. Electrocardiogram changes caused by muscle tremor during rigors could mimic a narrow complex tachycardia. Identification of muscle tremor as a cause of electrocardiogram artifact can avoid unnecessary pharmacological and non-pharmacological intervention to prevent arrhythmias.

  7. Late-Archaean crustal growth in the Lewisian Complex of Northwest Scotland: Diachroneity in magmatic accretion and implications for models of crustal growth

    Science.gov (United States)

    Whitehouse, M. J.

    The Lewisian Complex of northwestern Scotland is an Archaean basement terrain that was reworked during the Proterozoic. Previous geochronological studies have established that the complex represents an entirely new crustal addition during late-Archaean times, and the difference between a Sm-Nd accretion date of 2920 + or - 50 Ma and a Pb/Pb metamorphic date of 2680 + or - 70 Ma was interpreted as indicating a crustal accretion-differentiation superevent (CADS) lasting 240 + or - 110 Ma. A combined Rb-Sr, Pb/Pb, and Sm-Nd isotopic study reported was applied to the Lewisian CADS to attempt to address the problem of whether this comprised a short regional scale magmatic accretion event followed approximately 200 Ma later by regional high-grade metamorphism, or a long period of episodic or semi-continuous magmatic accretion prior to high-grade metamorphism.

  8. Effects of crustal thickness on magmatic differentiation in subduction zone volcanism: A global study

    Science.gov (United States)

    Farner, Michael J.; Lee, Cin-Ty A.

    2017-07-01

    The majority of arc magmas are highly evolved due to differentiation within the lithosphere or crust. Some studies have suggested a relationship between crustal thickness and magmatic differentiation, but the exact nature of this relationship is unclear. Here, we examine the interplay of crustal thickness and magmatic differentiation using a global geochemical dataset compiled from active volcanic arcs and elevation as a proxy for crustal thickness. With increasing crustal thickness, average arc magma compositions become more silicic (andesitic) and enriched in incompatible elements, indicating that on average, arc magmas in thick crust are more evolved, which can be easily explained by the longer transit and cooling times of magmas traversing thick arc lithosphere and crust. As crustal thickness increases, arc magmas show higher degrees of iron depletion at a given MgO content, indicating that arc magmas saturate earlier in magnetite when traversing thick crust. This suggests that differentiation within thick crust occurs under more oxidizing conditions and that the origin of oxidation is due to intracrustal processes (contamination or recharge) or the role of thick crust in modulating melting degree in the mantle wedge. We also show that although arc magmas are on average more silicic in thick crust, the most silicic magmas (>70 wt.% SiO2) are paradoxically found in thin crust settings, where average compositions are low in silica (basaltic). We suggest that extreme residual magmas, such as those exceeding 70 wt.% SiO2, are preferentially extracted from shallow crustal magma bodies than from deep-seated magma bodies, the latter more commonly found in regions of thick crust. We suggest that this may be because the convective lifespan of crustal magma bodies is limited by conductive cooling through the overlying crustal lid and that magma bodies in thick crust cool more slowly than in thin crust. When the crust is thin, cooling is rapid, preventing residual magmas

  9. Magnetic crustal thickness in Greenland from CHAMP and Ørsted data

    DEFF Research Database (Denmark)

    Maule, Cathrine Fox; Purucker, Michael E.; Olsen, Nils

    2005-01-01

    The magnetic crustal thickness of Greenland and the surrounding area is determined by inversion of gridded values of the magnetic radial component as given by the IDEMM model, which is based on CHAMP and Ørsted data alone, and by the Comprehensive Model (CM4), which is based on satellite and obse......The magnetic crustal thickness of Greenland and the surrounding area is determined by inversion of gridded values of the magnetic radial component as given by the IDEMM model, which is based on CHAMP and Ørsted data alone, and by the Comprehensive Model (CM4), which is based on satellite...

  10. Crustal growth of the Izu-Ogasawara arc estimated from structural characteristics of Oligocene arc

    Science.gov (United States)

    Takahashi, N.; Yamashita, M.; Kodaira, S.; Miura, S.; Sato, T.; No, T.; Tatsumi, Y.

    2011-12-01

    Japan Agency for Marine-Earth Science and Technology (JAMSTEC) carried out seismic surveys using a multichannel reflection system and ocean bottom seismographs, and we have clarified crustal structures of whole Izu-Ogasawara (Bonin)-Marina (IBM) arc since 2002. These refection images and velocity structures suggest that the crustal evolution in the intra-oceanic island arc accompanies with much interaction of materials between crust and mantle. Slow mantle velocity identified beneath the thick arc crusts suggests that dense crustal materials transformed into the mantle. On the other hand, high velocity lower crust can be seen around the bottom of the crust beneath the rifted region, and it suggests that underplating of mafic materials occurs there. Average crustal production rate of the entire arc is larger than expected one and approximately 200 km3/km/Ma. The production rate of basaltic magmas corresponds to that of oceanic ridge. Repeated crustal differentiation is indispensable to produce much light materials like continental materials, however, the real process cannot still be resolved yet. We, therefore, submitted drilling proposals to obtain in-situ middle crust with P-wave velocity of 6 km/s. In the growth history of the IBM arc, it is known by many papers that boninitic volcanisms preceded current bimodal volcanisms based on basaltic magmas. The current volcanisms accompanied with basaltic magmas have been occurred since Oligocene age, however, the tectonic differences to develop crustal architecture between Oligocene and present are not understood yet. We obtained new refraction/reflection data along an arc strike of N-S in fore-arc region. Then, we estimate crustal structure with severe change of the crustal thickness from refraction data, which are similar to that along the volcanic front. Interval for location of the thick arc crust along N-S is very similar to that along the volcanic front. The refection image indicates that the basement of the fore

  11. Crustal structure of western Hispaniola (Haiti) from a teleseismic receiver function study

    Science.gov (United States)

    Corbeau, J.; Rolandone, F.; Leroy, S.; Guerrier, K.; Keir, D.; Stuart, G.; Clouard, V.; Gallacher, R.; Ulysse, S.; Boisson, D.; Bien-aimé Momplaisir, R.; Saint Preux, F.; Prépetit, C.; Saurel, J.-M.; Mercier de Lépinay, B.; Meyer, B.

    2017-07-01

    Haiti, located at the northern Caribbean plate boundary, records a geological history of terrane accretion from Cretaceous island arc formations to the Eocene to Recent oblique collision with the Bahamas platform. Little is presently known about the underlying crustal structure of the island. We analyze P-waveforms arriving at 27 temporary broadband seismic stations deployed over a distance of 200 km across the major terrane boundaries in Haiti to determine the crustal structure of western Hispaniola. We compute teleseismic receiver functions using the Extended-Time Multi-Taper method and determine crustal thickness and bulk composition (Vp/Vs) using the H-k stacking method. Three distinctive and fault-bounded crustal domains, defined by their characteristic Moho depth distributions and bulk crustal Vp/Vs, are imaged across Haiti. We relate these domains to three crustal terranes that have been accreted along the plate boundary during the northeastwards displacement of the Caribbean plate and are presently being deformed in a localized fold and thrust belt. In the northern domain, made up of volcanic arc facies, the crust has a thickness of 23 km and Vp/Vs of 1.75 ± 0.1 typical of average continental crust. The crust in the southern domain is part of the Caribbean Large Igneous Province (Caribbean LIP), and is 22 km thick with Vp/Vs of 1.80 ± 0.03 consistent with plume-related rocks of late Cretaceous age. Significantly thicker, the crust in central Haiti has values of Moho depths averaging 41 km and with Vp/Vs of 1.80 ± 0.05. We propose that the central domain is likely constructed of an island arc upper crust with fragments of dense material originating from mafic lavas or LIP material. We produce a crustal profile along a N-S transect across Haiti accounting for the surface geology, shallow structural history, and new seismological constraints provided by variations of crustal thickness and bulk composition.

  12. Clinical Interrogation for Unveiling an Isolated Hypophysitis Mimicking Pituitary Adenoma.

    Science.gov (United States)

    Lee, Seungjoo; Choi, Jun Ho; Kim, Chang Jin; Kim, Jeong Hoon

    2017-03-01

    Hypophysitis is a rare disease entity mimicking a pituitary adenoma. Despite crucial disease involving a pituitary gland which is a main component of the hormonal axis, there have been minimal researches regarding the hypophysitis. In this study, we described the constellation of the preoperative findings including clinical, radiologic, and endocrinologic features, as well as postoperative outcomes of the hypophysitis. The authors reviewed the data retrospectively of a total of 2814 patients who underwent microsurgery at our institution to treat a pituitary mass lesion. Among them, the patients proven as hypophysitis in histologic examination were enrolled, followed by stratification into tumor-associated hypophysitis and isolated hypophysitis depending on the existence of associated tumor lesion. As a result, a total 21 cases were enrolled consisting of the 13 cases of tumor-associated and the 8 cases of isolated hypophysitis. In this study, the isolated hypophysitis was focused on the analysis. All patients with isolated hypophysitis were evaluated the clinical, radiologic, and endocrinologic tests preoperatively. After microsurgery, all patients had a minimum follow up of 6 months (6∼72 months). The clinical symptoms, endocrinologic tests, and brain MRI were checked at every 6 months during first 2 year, since then, at every 12 months. Among 2814 cases of pituitary mass lesion underwent microsurgery, the hypophysitis were found 21 cases (0.74 %). The 13 cases were the tumor-associated hypophysitis, consisting of rathke's cleft cyst (7 cases), craniopharyngioma (3 cases), pituitary adenoma (2 cases), and germinoma (1 case). The 8 cases were the isolated hypophysitis including lymphocytic (4 cases), granulomatous (3 cases), and IgG4-related (1 case) hypophysitis. The patients presented a wide range of clinical symptoms from general weakness to panhypopituitarism. In addition, the most remarkable radiologic features of the isolated hypophysitis were infundibular

  13. Primary pleural thymoma mimicking signs of another tumor

    Directory of Open Access Journals (Sweden)

    Editorial Office

    2016-12-01

    Owing to their peculiar location and a variety of manifested histologic patterns, pleural thymomas may be confused with other neoplasms and may cause diagnostic problems clinically, radiologically, and morphologically,” the researchers explained. In their case report, Monaco and his co-authors highlighted several instances of lesions that need to be examined more closely by physicians during differential diagnosis in order to distinguish primary pleural thymoma from other neoplasms, especially malignant mesotheliomas, as in their case study. In rare instances, according to the authors, malignant mesotheliomas may have a significant infiltration of the lymphoid, thus giving rise to diagnostic mistakes. In addition, they pointed out that close similarities may exist between thymic tumors and malignant mesothelioma in small biopsies, thus making analysis problematic. “An awareness of these interpretative pitfalls is important to prevent misdiagnosis of malignant pleural mesothelioma,” they cautioned. “Because of their ectopic site and variety of histologic patterns, as well as the occurrence of an ‘invasive’ border, diagnosis of primary pleural thymomas via pleural biopsy can be very difficult, especially if the pathologist is not aware of this entity or if the typical features of thymoma are lacking,” the researchers said. Owing to the possibility of thymomas mimicking both radiological and microscopical lesions, Monaco and fellow authors stressed upon the consideration of a primary pleural thymoma in the diagnostic approach concerning pleural pathology. Their diagnosis of pleural thymoma in their patient, outlined in their case report, was established based on careful examination of histological features, combined with radiographic, and surgical findings — which they argued “should be considered essential for excluding any mediastinal involvement.” Hence, “[a] combination of clinical information, histopathologic appearance of the tumor, and

  14. Crustal structure revealed by a deep seismic sounding profile of Baijing-Gaoming-Jinwan in the Pearl River Delta

    Science.gov (United States)

    Zhang, Xiang; Ye, Xiuwei; Lv, Jinshui; Sun, Jinlong; Wang, Xiaona

    2018-02-01

    The Pearl River Estuary area, located in the middle part of the southern China coastal seismic belt, has long been considered a potential source of strong earthquakes above magnitude 7.0. To scientifically assess the potential strong earthquake risk in this area, a three-dimensional artificial seismic sounding experiment, consisting of a receiving array and seabed seismograph, was performed to reveal the deep crustal structure in this region. We used artificial ship-borne air-gun excitation shots as sources, and fixed and mobile stations as receivers to record seismic data from May to August 2015. This paper presents results along a line from the western side of the Pearl River Estuary to the western side of the Baijing-Gaoming-Jinwan profile. A two-dimensional velocity structure was constructed using seismic travel-time tomography. The inversion results show that the Moho depth is 27 km in the coastal area and 30 km in the northwest of the Pearl River Estuary area, indicating that the crust thins from land to sea. Two structural discontinuities and multiple low-velocity anomalies appear in the crustal section. Inside both discontinuity zones, a low-velocity layer, with a minimum velocity of 6.05 km s-1, exists at a depth of about 15 km, and another, with a minimum velocity of 6.37 km s-1, exists at a depth of about 21.5 km between the middle and lower crust. These low velocities suggest that the discontinuities may consist of partly molten material. Earthquakes with magnitudes higher than 5.0 occurred in the low-velocity layer along the profile. The deep Kaiping-Enping fault, rooted in the crust, may be one of the most important channels for deep material upwelling and is related to tectonic movement since the Cretaceous in the Pearl River Delta tectonic rift basin.

  15. NMR and EPR Studies of Free-Radical Intermediates from Experiments Mimicking the Winds on Mars

    DEFF Research Database (Denmark)

    Jakobsen, Hans J.; Song, Likai; Gan, Zhehong

    2016-01-01

    -enriched methane ((CH4)-C-13 and CD4), carbon dioxide ((CO2)-C-13), hydrogen (H-2(2)) and oxygen (O-17(2)). The solid-state Si free-radical intermediate and gas reaction and silicate products are formed in a specially designed rotating apparatus, which by mechanical tumbling mimics the winds and collision......A new kind of solid gas chemical reactions has been investigated using solid-state powder H-2, C-13, and Si-29 NMR and EPR spectroscopies. These studies involve reactions between a silicate-created Si free-radical intermediate and a few ordinary gases such as isotopically H-2-, C-13-, and O-17...... speed of the mineral particles on Mars. It is shown that the "hard" quartz (SiO2) or corundum (alpha-AL(2)O(3)) grain particles, used to simulate the collision particles in a rotating Pyrex (borosilicate) reaction flask, act as an abrasive on the "soft" Pyrex flask and thereby create a silicate Si free...

  16. Vertical crustal movements in Southern California, 1974 to 1978

    Science.gov (United States)

    Burford, R.O.; Gilmore, Thomas D.

    1984-01-01

    An extensive resurvey of most of the first-order leveling network in southern California, known as the Southern California Releveling Program (SCRP), was carried out during the first 5 months of 1978. The primary scientific purpose of these measurements was to rapidly update the vertical control record throughout a recently uplifted region of southern California in order to more thoroughly document the vertical component of tectonic movement and to provide a reliable base for comparison with future levelings. Analyses of historic first-order leveling results have clearly demonstrated that a broad crustal upwarping, largely contained within a region consisting of the Transverse Ranges province and an area along the intervening section of the San Andreas fault system, had developed between about 1959 and 1974. Unfortunately, there is strong evidence that parts of the 1978 SCRP data are contaminated by the effects of intrasurvey tectonic deformation, limited surficial failures, and, less certainly, magnetically induced systematic error associated with the use of automatic levels. However, any distortions in leveling results caused by these or other factors are not so serious as to render the SCRP data useless. In fact, the bulk of these data can be accepted at face value, and most of the remaining data can be incorporated with some caution to augment the more reliable parts of the network. The evaluation of the 1978 leveling is based on a combination of circuit-misclosures, local timing of the field observations, analysis of profiles of apparent height changes derived from comparisons with previous levelings, and an analysis of the position and orientation of the various routes in relation to the regional structural grain and the gradients of differential vertical motion established by previous investigations. Comparisons of the 1978 SCRP results with the latest of the previous surveys along each route retained in the analysis show that all but about one-third of the

  17. Crustal evolution at mantle depths constrained from Pamir xenoliths

    Science.gov (United States)

    Kooijman, E.; Hacker, B. R.; Smit, M. A.; Kylander-Clark, A. R.; Ratschbacher, L.

    2012-12-01

    Lower crustal xenoliths erupted in the Pamir at ~11 Ma provide an exclusive opportunity to study the evolution of crust at mantle depths during a continent-continent collision. To investigate, and constrain the timing of, the petrologic processes that occurred during burial to the peak conditions (2.5-2.8 GPa, 1000-1100 °C; [1]), we performed chemical- and isotope analyses of accessory minerals in 10 xenoliths, ranging from eclogites to grt-ky-qtz granulites. In situ laser ablation split-stream ICPMS yielded 1) U-Pb ages, Ti concentrations and REE in zircon, 2) U/Th-Pb ages and REE in monazite, and 3) U-Pb ages and trace elements in rutile. In addition, garnet, and biotite and K-feldspar were dated using Lu-Hf and 40Ar/39Ar geochronology, respectively. Zircon and monazite U-(Th-)Pb ages are 101.9±1.8, 53.7±1.0, 39.1±0.8, 21.7±0.4, 18.2±0.5, 16.9±0.8, 15.1±0.3 (2σ) and 12.5-11.1 Ma; most samples showed several or all of these populations. The 53.7 Ma and older ages are xenocrystic or detrital. For younger ages, zircon and monazite in individual samples recorded different ages-although zircon in one rock and monazite in another can be the same age. The 39.1 Ma zircon and monazite mostly occur as inclusions in minerals of the garnet-bearing assemblage that represents the early, low-P stages of burial. Garnet Lu-Hf ages of 37.8±0.3 Ma support garnet growth at this time. Spinifex-like textures containing 21.7-11.1 Ma zircon and monazite record short-lived partial melting events during burial. Aligned kyanite near these patches indicates associated deformation. Zircons yielding ≤12.5 Ma exhibit increased Eu/Eu* and markedly decreased HREE concentrations, interpreted to record feldspar breakdown and omphacite growth during increasing pressure. Rutile U-Pb cooling ages are 10.8±0.3 Ma in all samples. This agrees with the weighted mean 40Ar/39Ar age of eight biotite, K-feldspar and whole rock separates of 11.00+0.16/-0.09 Ma. Rutile in eclogites provides Zr

  18. Crustal Thickness and Lithospheric Structure in Northwestern Namibia from the WALPASS experiment

    OpenAIRE

    Benjamin Heit; Xiaohui Yuan; W. Geissler; B. Lushetile; Michael Weber; Jokat, W.

    2013-01-01

    An amphibian passive-source seismic network (WALPASS) have been deployed for a period of two years in the area where theWalvis Ridge intersects with the continental margin of northwestern Namibia. The deployment was intended to study and map the lithospheric and upper mantle structure in the ocean-continent transition beneath the passive continental margin. The main idea is to find seismic anomalies related to the postulated hotspot track from the continent to the ocean along the Walvis Ridge...

  19. Evaluating Crustal Contamination Effects On The Lithophile Trace Element Budget Of Shergottites, NWA 856 As A Test Case

    Science.gov (United States)

    Brandon, A. D.; Ferdous, J.; Peslier, A. H.

    2017-01-01

    The issue of whether crustal contamination has affected the lithophile trace element budget of shergottites has been a point of contention for decades. The evaluation has focused on the enriched shergottite compositions as an outcome of crustal contamination of mantle-derived parent magmas or, alternatively, the compositions of these stones reflect an incompatible trace element (ITE) enriched mantle source.

  20. Observation of seafloor crustal movement using the seafloor acoustic ranging on Kumano-nada

    Science.gov (United States)

    Osada, Y.; Kido, M.; Fujimoto, H.

    2010-12-01

    Along the Nankai Trough, where the Philippine Sea plate subducts under southeastern Japan with a convergence rate of about 65 mm/yr, large interplate thrust earthquakes of magnitude 8 class have occurred repeatedly with recurrence intervals of 100-200 years. About 60 years have passed since the last earthquakes happened in 1944 and 1946. Therefore it is important to monitor the tectonic activities in the Nankai Trough. Since most of the source region of the earthquakes is located beneath the ocean, an observation system is necessary in the offshore source region. We developed a seafloor acoustic ranging system to continuously monitor the seafloor crustal movement. We aim to monitor the activity in the splay faults in the rupture area of the Tonankai earthquake in the Nankai subduction zone. Slips along the active splay faults may be an important mechanism that the elastic strain caused by relative plate motion. We carried out two experiments, a short-term (one day) and a long-term (four month) experiments, to estimate the repeatability of acoustic measurements of this system. We deployed four PXPs (precision acoustic transponders) with about 600 m (M2-S1 baseline) and 920 m (M2-S2 base line) spacing in the long-term experiment. The standard deviation in acoustic measurements was about 1 cm on each baseline. In September 2008 we carried out an observation to monitor an active splay faults on Kumano-Nada prism slope. We deployed three PXPs with about 925 m (M1-S2 baseline) and 725 m (M1-S2 base line) spacing at the depth of some 2880 m. We recovered them in August 2010 to get data of acoustic measurements for 6 month and pressure measurements for 18 month. The round trip travel time shows a variation with peak-to-peak amplitude of about 1msec. We preliminarily collected the time series of round trip travel times using sound speed, which was estimated from measured temperature and pressure, and attitude data. We discuss the result of a variation of distance.

  1. Impact of acoustic velocity structure to measurement of ocean bottom crustal deformation

    Science.gov (United States)

    Ikuta, R.; Tadokoro, K.; Okuda, T.; Sugimoto, S.; Watanabe, T.; Eto, S.; Ando, M.

    2010-12-01

    We are developing a geodetic method of monitoring crustal deformation under the ocean using kinematic GPS and acoustic ranging. The goal of our research is to achieve sub-centimeter accuracy in measuring oceanic crustal deformation by a very short-time measurement like 10 hours. In this study, we focused on lateral variation of acoustic velocity structure in seawater and introduced an inclined acoustic velocity structure model to improve accuracy of the measurement. We have a few measurement sites along Nankai trough, Japan. In each sites, we deployed a trio of transponders on ocean floor (seafloor benchmark units) within distance comparable with the depth. An ultrasonic signal is generated from a surface vessel drifting over the benchmark unit, which is received and replied by the benchmark unit. In this system, both acoustic velocity structure and the benchmark unit positions were determined simultaneously for the each measurement using a tomographic technique. This tomographic technique was adopted on an assumption that the acoustic velocity structure is horizontally layered and changes only in time, not in space. Ikuta et al., (AGU fall meeting 2009) reported an approach to improve accuracy of benchmark positioning using a new additional assumption. The additional assumption was that the configuration of the transponders trio constituting one benchmark unit does not change. They determined the time evolution of weight center for the fixed transponder triangle between different measurements using all repetitively obtained data sets at once. This is contrasting to the previous method in which each data set for different measurement was solved independently. This assumption worked well in reducing number of unknown parameters. As a result, repeatability of benchmark positioning improved from 5 cm to 3 cm. We conducted numerical experiments synthesizing acoustic travel-time data to evaluate the robustness of this new approach. When acoustic travel-time data is

  2. Multilocular peritoneal inclusion cyst mimicking an ovarian tumor: A case report

    OpenAIRE

    Singh, Anju; Sehgal, Alka; Mohan, Harsh

    2015-01-01

    Peritoneal inclusion cysts are uncommon abdominopelvic cysts seen in perimenopausal women. It is often misdiagnosed clinically as an ovarian tumor due to similar presentation and mimicking findings on radiology. We describe a perimenopausal woman presenting with pelvic mass. Her clinical finding on radiology suggested an ovarian tumor; however, biopsy revealed it as peritoneal inclusion cysts. We discuss the possible ways to avoid such mistakes.

  3. A Case Report of Syringocystadenoma Papilliferum Mimicking Basal Cell Carcinoma on the Face

    Directory of Open Access Journals (Sweden)

    Engin Sezer

    2012-03-01

    Full Text Available Syringocystadenoma papilliferum is clinically characterized by verrucous nodules or plaques, mainly observed on the scalp during childhood. Histopathologically, epidermal invagination showing luminal epithelial cells with decapitation secretion is diagnostic. Herein, we describe an unusual late-onset case of syringocystadenoma papilliferum mimicking basal cell carcinoma on the face.

  4. Charcot arthropathy of the lumbosacral spine mimicking a vertebral tumor after spinal cord injury.

    Science.gov (United States)

    Son, Soo-Bum; Lee, Sun-Ho; Kim, Eun-Sang; Eoh, Whan

    2013-12-01

    Charcot spinal arthropathy is a rare, progressive type of vertebral joint degeneration that occurs in the setting of any preexisting condition characterized by decreased afferent innervation to the extent that normal protective joint sensation in the vertebral column is impaired. The authors report on a case of Charcot arthropathy of the lower lumbar spine mimicking a spinal tumor following cervical cord injury.

  5. Charcot Arthropathy of the Lumbosacral Spine Mimicking a Vertebral Tumor after Spinal Cord Injury

    OpenAIRE

    Son, Soo-Bum; Lee, Sun-Ho; Kim, Eun-Sang; Eoh, Whan

    2013-01-01

    Charcot spinal arthropathy is a rare, progressive type of vertebral joint degeneration that occurs in the setting of any preexisting condition characterized by decreased afferent innervation to the extent that normal protective joint sensation in the vertebral column is impaired. The authors report on a case of Charcot arthropathy of the lower lumbar spine mimicking a spinal tumor following cervical cord injury.

  6. Tuberculosis mimicking ileocecal intussusception in a 5-month-old girl

    NARCIS (Netherlands)

    J.E.M. de Steenwinkel (Jurriaan); G.J.A. Driessen (Gertjan); M.H. Kamphorst-Roemer (Margreet); A.G.M. Zeegers (Antoine); A. Ott (Alewijn); M. van Westreenen (Mireille)

    2008-01-01

    textabstractA 5-month-old girl was diagnosed with tuberculosis, mimicking ileocecal intussusception. The mother of the patient was later diagnosed with renal tuberculosis attributable to the same (unique) Mycobacterium tuberculosis strain. Possibly, that transmission occurred by aspiration or

  7. Factitious disorder mimicking addiction to levodopa in a patient with advanced Parkinson's disease

    OpenAIRE

    Teixeira-Jr,Antônio L.; Cardoso,Francisco

    2005-01-01

    We report a 43-year-old woman with early-onset Parkinson's disease in whom neurological control was impaired by psychiatric co-morbidity including major depression and panic disorder. The patient also met criteria for factitious disorder that mimicked dopamine dysregulation syndrome resulting in severe clinical and social disability.

  8. Factitious disorder mimicking addiction to levodopa in a patient with advanced Parkinson's disease.

    Science.gov (United States)

    Teixeira-Júnior, Antônio L; Cardoso, Francisco

    2005-06-01

    We report a 43-year-old woman with early-onset Parkinson's disease in whom neurological control was impaired by psychiatric co-morbidity including major depression and panic disorder. The patient also met criteria for factitious disorder that mimicked dopamine dysregulation syndrome resulting in severe clinical and social disability.

  9. Atypical hepatic hemangiomas with multiple calcifications mimicking hepatic metastases: case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Hwan; Kim, Hyun Cheol; Shin, Hyeong Cheol; Park, Seong Il; Kim, Hong Soo; Bae, Won Kyung; Kim, Il Young [Cheonan Hospital, Cheonan (Korea, Republic of); Oh, Mee Hye; Yang, Seung Ha [College of Medicine, Soonchunhyang Univ., Cheonan (Korea, Republic of)

    2004-07-01

    Although hepatic hemangioma is the most common benign tumor of the liver, it is rarely associated with calcifications. We report on the case of an asymptomatic 58-year-old man in whom multiple hepatic masses containing calcifications were discovered incidentally at ultrasonography. The radiologic features mimicked those of multiple hepatic metastases.

  10. Herpes Simplex Virus (HSV-1 Encephalitis Mimicking Glioblastoma: Case Report and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Burke A. Cunha

    2014-12-01

    Full Text Available Glioblastoma multiforme (GBM often presents as a brain mass with encephalitis. In a patient with GBM, subsequent presentation with new onset encephalitis may be due to another GBM or Herpes simplex virus 1 (HSV-1 encephalitis. We present a case of HSV-1 encephalitis mimicking GBM in a patient with previous GBM.

  11. Acute Fulminant Uremic Neuropathy Following Coronary Angiography Mimicking Guillain–Barre Syndrome

    Science.gov (United States)

    Priti, Kumari; Ranwa, Bhanwar

    2017-01-01

    A 55-year-old diabetic woman suffered a posterior wall ST-elevation myocardial infarction. She developed contrast-induced nephropathy following coronary angiography. Acute fulminant uremic neuropathy was precipitated which initially mimicked Guillan–Barre Syndrome, hence reported. PMID:28706599

  12. Case report: Pulmonary syphilis mimicking pulmonary hematogenous metastases on chest CT and integrated PET/CT

    Directory of Open Access Journals (Sweden)

    Hyung Jun Kim

    2011-01-01

    Full Text Available We report a case of syphilis with pulmonary involvement. Chest CT scan and 18 F-fluorodeoxyglucose (FDG PET/CT showed multiple pulmonary nodules mimicking pulmonary hematogenous metastases. This was confirmed on follow-up images that showed therapeutic response to penicillin.

  13. Collar Osteophytes Mimicking Osteonecrosis in Planar Bone Scintigraphy and Usefulness of SPECT/CT Images.

    Science.gov (United States)

    Juang, Jr-Jian; Chen, Yi-Hsing; Tsai, Shih-Chuan; Lin, Wan-Yu

    2017-03-01

    The use of prednisolone is one major risk factor for osteonecrosis in patients with systemic lupus erythematosus. Bone scintigraphy can be a diagnostic tool for early diagnosis. We present a case who had collar osteophytes at the bilateral femoral heads, which mimicked osteonecrosis in the planar bone scintigram. An SPECT/CT scan avoided this pitfall and increased the diagnostic accuracy for osteonecrosis.

  14. Redox enzyme-mimicking activities of CeO2nanostructures: Intrinsic influence of exposed facets.

    Science.gov (United States)

    Yang, Yushi; Mao, Zhou; Huang, Wenjie; Liu, Lihua; Li, Junli; Li, Jialiang; Wu, Qingzhi

    2016-10-17

    CeO 2 nanoparticles (NPs) have been well demonstrated as an antioxidant in protecting against oxidative stress-induced cellular damages and a potential therapeutic agent for various diseases thanks to their redox enzyme-mimicking activities. The Ce 3+ /Ce 4+ ratio and oxygen vacancies on the surface have been considered as the major originations responsible for the redox enzyme-mimicking activities of CeO 2 NPs. Herein, CeO 2 nanostructures (nanocubes and nanorods) exposed different facets were synthesized via a facile hydrothermal method. The characterizations by X-ray photoelectron spectroscopy, Raman spectroscopy, and UV-Vis spectroscopy show that the Ce 3+ /Ce 4+ ratio and oxygen vacancy content on the surfaces of as-synthesized CeO 2 nanostructures are nearly at the same levels. Meanwhile, the enzymatic activity measurements indicate that the redox enzyme-mimicking activities of as-synthesized CeO 2 nanostructures are greatly dependent on their exposed facets. CeO 2 nanocubes with exposed {100} facets exhibit a higher peroxidase but lower superoxide dismutase activity than those of the CeO 2 nanorods with exposed {110} facets. Our results provide new insights into the redox enzyme-mimicking activities of CeO 2 nanostructures, as well as the design and synthesis of inorganic nanomaterials-based artificial enzymes.

  15. Mild toxic anterior segment syndrome mimicking delayed onset toxic anterior segment syndrome after cataract surgery

    Directory of Open Access Journals (Sweden)

    Su-Na Lee

    2014-01-01

    Full Text Available Toxic anterior segment syndrome (TASS is an acute sterile postoperative anterior segment inflammation that may occur after anterior segment surgery. I report herein a case that developed mild TASS in one eye after bilateral uneventful cataract surgery, which was masked during early postoperative period under steroid eye drop and mimicking delayed onset TASS after switching to weaker steroid eye drop.

  16. Solid-phase synthesis of an apoptosis-inducing tetrapeptide mimicking the Smac protein

    DEFF Research Database (Denmark)

    Le Quement, Sebastian Thordal; Ishøy, Mette; Petersen, Mette Terp

    2011-01-01

    An approach for the solid-phase synthesis of apoptosis-inducing Smac peptidomimetics is presented. Using a Rink linker strategy, tetrapeptides mimicking the N-4-terminal residue of the Smac protein [(N-Me)AVPF sequence] were synthesized on PEGA resin in excellent purities and yields. Following two...

  17. Pilocytic astrocytoma of the cerebellopontine angle mimicking vestibular schwannoma: report of a rare entity.

    Science.gov (United States)

    Dutta, Gautam; Singh, Daljit; Singh, Hukum; Sachdeva, Deepashu; Kumar, Vikas; Chaturvedi, Ashutosh

    2017-12-26

    We present a rare case of a 55-yr old patient of pilocytic astrocytoma of the cerebello-pontine angle mimicking a vestibular schwannoma. The tumor protruded into the porus acusticus causing enlargement of the internal auditory meatus, which is quite an unusual feature of glial tumours.

  18. Abdominal Tuberculosis Mimicking Metastasis in a Patient with Carcinoma of the Oesophagus

    Directory of Open Access Journals (Sweden)

    Hester Yui Shan Cheung

    2006-01-01

    Full Text Available Oesophageal carcinoma typically manifests as ulcerative growth. Cases of oesophageal tuberculosis mimicking carcinoma of the oesophagus have been reported and create considerable diagnostic difficulty. Abdominal tuberculosis, however, is an uncommon extrapulmonary manifestation of tuberculosis. Here, we report a case of abdominal tuberculosis in a patient with squamous carcinoma of the oesophagus.

  19. An unusual foreign body in the urinary bladder mimicking a parasitic worm.

    Science.gov (United States)

    Schmitt, Bryan H; Feder, Marc T; Rokke, Denise L; Moyer, Thomas P; Pritt, Bobbi S

    2012-07-01

    We report an unusual case of a foreign body removed from the urinary bladder of a 63-year-old male which mimicked a parasitic worm. The foreign body was identified as an artificial fishing worm by morphological comparison to a similar commercially produced product and by infrared spectrum analysis.

  20. Validation of a new blood-mimicking fluid for use in Doppler flow test objects

    NARCIS (Netherlands)

    Ramnarine, KV; Nassiri, DK; Hoskins, PR; Lubbers, J

    A blood-mimicking fluid (BMF) suitable for use in Doppler flow test objects is described and characterised, The BMF consists of 5 mu m diameter nylon scattering particles suspended in a fluid base of water, glycerol, dextran and surfactant, The acoustical properties of various BMF preparations were

  1. Seasonal crustal seismic velocity changes in Japan from noise-based monitoring

    Science.gov (United States)

    WANG, Q. Y.; Brenguier, F.; Campillo, M.; Lecointre, A.; Takeda, T.; Aoki, Y.; Longuevergne, L.

    2016-12-01

    The general framework of this work is to study how environmental seasonal perturbations impact the solid Earth in an active tectonic region. For this purpose we continuously monitor crustal seismic velocity changes using noise-based monitoring over the entire Japan. We perform a massive data analysis of the continuous seismic records of the very dense Hi-net short-period network (800 stations) from 2008 to 2012. When mapping seasonal velocity changes over the entire Japan we find large anomalies in the southern Kyushu island and in the Northern Hokkaido island. Transient seasonal crustal drops of seismic velocity in Kyushu are well explained by a model of pore pressure increase induced by heavy precipitation in summer during typhoon period. The other large seasonal anomaly located in Eastern Hokkaido (North Japan) shows both an effect of increased pore pressure during precipitation in summer (velocity decrease) and of closure of crustal cracks in winter (velocity increase) explained by both the effects of snow loading and pore pressure decrease by water drainage. The response of the crust in western Japan (Hokkaido and Honshu) is more enigmatic as it shows a very small sensitivity to both precipitation and snow loads effects. Finally, we show how better understanding these environmentally induced crustal perturbations improves our observations of tectonic-induced seismic property changes in the special case of the M9, 2011, Tohoku-Oki earthquake.

  2. Volcanoes: Where and Why? Crustal Evolution Education Project. Teacher's Guide [and] Student Investigation.

    Science.gov (United States)

    Stoever, Edward C., Jr.

    Crustal Evolution Education Project (CEEP) modules were designed to: (1) provide students with the methods and results of continuing investigations into the composition, history, and processes of the earth's crust and the application of this knowledge to man's activities and (2) to be used by teachers with little or no previous background in the…

  3. Electron impact ionization in the Martian atmosphere: Interplay between scattering and crustal magnetic field effects

    Science.gov (United States)

    Lillis, Robert J.; Fang, Xiaohua

    2015-07-01

    Precipitating electrons are typically the dominant source of energy input into Mars' nighttime upper atmosphere, with consequences for atmospheric and ionospheric structure, composition, chemistry, and electrodynamics. Mars' spatially heterogeneous crustal magnetic fields affect the fluxes of precipitating electrons, via both the magnetic mirror force and Gauss' law of conservation of magnetic flux. We use a kinetic electron transport model to examine ionization rate profiles that result from the combination of these magnetic effects and elastic and inelastic scattering by atmospheric neutrals. Specifically, we calculate ionization rates as a function of altitude, crustal magnetic field strength, and the initial energy and pitch angle of the precipitating electrons, covering the relevant ranges of these parameters. Several complex behaviors are exhibited, including bifurcating ionization peaks with distinct characteristics and energy-dependent and crustal field strength-dependent increases in ionization with decreasing pitch angle. Elucidating such behavior is important for understanding the effect of Mars' unique crustal fields on the Mars upper atmosphere and ionosphere, both to predict the consequences of measured electron precipitation and to enable, for the first time, downward coupling of global plasma models with thermosphere-ionosphere models.

  4. Oceanic crustal carbon cycle drives 26-million-year atmospheric carbon dioxide periodicities.

    Science.gov (United States)

    Müller, R Dietmar; Dutkiewicz, Adriana

    2018-02-01

    Atmospheric carbon dioxide (CO 2 ) data for the last 420 million years (My) show long-term fluctuations related to supercontinent cycles as well as shorter cycles at 26 to 32 My whose origin is unknown. Periodicities of 26 to 30 My occur in diverse geological phenomena including mass extinctions, flood basalt volcanism, ocean anoxic events, deposition of massive evaporites, sequence boundaries, and orogenic events and have previously been linked to an extraterrestrial mechanism. The vast oceanic crustal carbon reservoir is an alternative potential driving force of climate fluctuations at these time scales, with hydrothermal crustal carbon uptake occurring mostly in young crust with a strong dependence on ocean bottom water temperature. We combine a global plate model and oceanic paleo-age grids with estimates of paleo-ocean bottom water temperatures to track the evolution of the oceanic crustal carbon reservoir over the past 230 My. We show that seafloor spreading rates as well as the storage, subduction, and emission of oceanic crustal and mantle CO 2 fluctuate with a period of 26 My. A connection with seafloor spreading rates and equivalent cycles in subduction zone rollback suggests that these periodicities are driven by the dynamics of subduction zone migration. The oceanic crust-mantle carbon cycle is thus a previously overlooked mechanism that connects plate tectonic pulsing with fluctuations in atmospheric carbon and surface environments.

  5. Lithospheric Thickness Variations from Gravity and Topography in Areas of High Crustal Remanent Magnetization on Mars

    Science.gov (United States)

    Smrekar, S. E.; Raymond, C. A.

    2001-01-01

    Large regions of intense crustal re- manent magnetization were fortuitously discovered on Mars by the Mars Global Surveyor (MGS) spacecraft. Gravity and topography admittance studies are used to examine lithospheric structure in the areas of intense magnetization. Areas with positively magnetized crust appear to have thinner crust and elastic lithosphere than negatively magnetized crust. Additional information is contained in the original extended abstract.

  6. Tropics in Antarctica? Crustal Evaluation Education Project. Teacher's Guide [and] Student Investigation.

    Science.gov (United States)

    Stoever, Edward C., Jr.

    Crustal Evolution Education Project (CEEP) modules were designed to: (1) provide students with the methods and results of continuing investigations into the composition, history, and processes of the earth's crust and the application of this knowledge to man's activities and (2) to be used by teachers with little or no previous background in the…

  7. Reconstruction of the pre-breakup crustal thickness in Australia/Antarctica

    Science.gov (United States)

    Goncharov, A.

    2003-04-01

    Some 140 million years ago, Australia and Antarctica were parts of a single continent Gondwana. Before it broke into parts there was a process of extensive crustal extension. Thinning of the crust during this process was accompanied by deposition of vast amounts of sedimentary rocks along Australia’s Southern Margin, where the total sediment thickness locally (e.g., Ceduna Sub-basin) reaches 15 km. These sedimentary rocks may have been involved in oil and gas formation. Knowledge of the pre-breakup crustal thickness in Australia/Antarctica is important because it provides additional constraints for plate tectonic reconstructions of the two continents and ultimately leads to a more accurate assessment of the petroleum potential of Australia’s Southern Margin. Most reliable estimates of crustal thickness come from refraction seismic measurements which define the depth to the Moho boundary, where seismic velocity increases to 8 km/s or more. Such measurements were used in this research for Australia. Unlike Australia, Antarctica has poor coverage of seismic measurements of crustal thickness. For Antarctica, seismic measurements were supplemented by values predicted by the regression between seismically defined crustal thickness and upwardly continued gravity. Upward continuation emphasizes the effects of variations in crustal thickness in the total gravity signal. After compilation and computation of crustal thickness was completed, data points located on Australian continent were reconstructed to their pre-breakup position. The most up-to-date finite rotation parameters defining the movement of Australia relative to Antarctica were used in this process. To ensure that pre-breakup extension and thinning of the crust (during the 140 to 95 Ma time interval) were accounted for, points with crustal thickness values less than 30 km on both Australian and Antarctic margins were excluded from subsequent gridding. Crust thinner than 30 km was taken to have been affected

  8. Magmatic recharge buffers the isotopic compositions against crustal contamination in formation of continental flood basalts

    Science.gov (United States)

    Yu, Xun; Chen, Li-Hui; Zeng, Gang

    2017-07-01

    Isotopic compositions of continental flood basalts are essential to understand their genesis and to constrain the character of their mantle sources. Because of potential crustal contamination, it needs to be evaluated if and to which degree these basalts record original isotopic signals of their mantle sources and/or crustal signatures. This study examines the Sr, Nd, Hf, and Pb isotopic compositions of the late Cenozoic Xinchang-Shengzhou (XS) flood basalts, a small-scale continental flood basalt field in eastern China. The basalts show positive correlations between 87Sr/86Sr and 143Nd/144Nd, and negative correlations between 143Nd/144Nd and 176Hf/177Hf, which deviate from compositional arrays of crustal contamination and instead highlight variations in magmatic recharge intensity and mantle source compositions. The lava samples formed by high-volume magmatic recharge recorded signals of recycled sediments in the mantle source, which are characterized by moderate Ba/Th (91.9-106.5), excess 208Pb/204Pb relative to 206Pb/204Pb, and excess 176Hf/177Hf relative to 143Nd/144Nd. Thus, we propose that magmatic recharge buffers the original isotopic compositions of magmas against crustal contamination. Identifying and utilizing the isotope systematics of continental flood basalts generated by high volumes of magmatic recharge are thus crucial to trace their mantle sources.

  9. On the geographical distribution of induced time-varying crustal magnetic fields

    DEFF Research Database (Denmark)

    Thebault, E.; Hemant, K.; Hulot, G.

    2009-01-01

    of the Earth's crust. For spherical harmonic degrees 15-90, we estimate the root mean square of the crustal magnetic field secular variation to amount 0.06-0.12 nT/yr at the terrestrial surface between epochs 1960-2002.5. The geographical distribution of the signal shows absolute values reaching 0.65-1.30 n...

  10. A Unified Global Reference Frame of Vertical Crustal Movements by Satellite Laser Ranging

    Directory of Open Access Journals (Sweden)

    Xinhui Zhu

    2016-02-01

    Full Text Available Crustal movement is one of the main factors influencing the change of the Earth system, especially in its vertical direction, which affects people’s daily life through the frequent occurrence of earthquakes, geological disasters, and so on. In order to get a better study and application of the vertical crustal movement,as well as its changes, the foundation and prerequisite areto devise and establish its reference frame; especially, a unified global reference frame is required. Since SLR (satellite laser ranging is one of the most accurate space techniques for monitoring geocentric motion and can directly measure the ground station’s geocentric coordinates and velocities relative to the centre of the Earth’s mass, we proposed to take the vertical velocity of the SLR technique in the ITRF2008 framework as the reference frame of vertical crustal motion, which we defined as the SLR vertical reference frame (SVRF. The systematic bias between other velocity fields and the SVRF was resolved by using the GPS (Global Positioning System and VLBI (very long baseline interferometry velocity observations, and the unity of other velocity fields and SVRF was realized,as well. The results show that it is feasible and suitable to take the SVRF as a reference frame, which has both geophysical meanings and geodetic observations, so we recommend taking the SLR vertical velocity under ITRF2008 as the global reference frame of vertical crustal movement.

  11. Crustal rheology of the Himalaya and Southern Tibet inferred from magnetotelluric data

    Science.gov (United States)

    Unsworth, M. J.; Jones, A. G.; Wei, W.; Marquis, G.; Gokarn, S. G.; Spratt, J. E.; Bedrosian, Paul; Booker, John; Leshou, Chen; Clarke, Greg; Shenghui, Li; Chanhong, Lin; Ming, Deng; Sheng, Jin; Solon, Kurt; Handong, Tan; Ledo, Juanjo; Roberts, Brian

    2005-11-01

    The Cenozoic collision between the Indian and Asian continents formed the Tibetan plateau, beginning about 70million years ago. Since this time, at least 1,400km of convergence has been accommodated by a combination of underthrusting of Indian and Asian lithosphere, crustal shortening, horizontal extrusion and lithospheric delamination. Rocks exposed in the Himalaya show evidence of crustal melting and are thought to have been exhumed by rapid erosion and climatically forced crustal flow. Magnetotelluric data can be used to image subsurface electrical resistivity, a parameter sensitive to the presence of interconnected fluids in the host rock matrix, even at low volume fractions. Here we present magnetotelluric data from the Tibetan-Himalayan orogen from 77°E to 92°E, which show that low resistivity, interpreted as a partially molten layer, is present along at least 1,000km of the southern margin of the Tibetan plateau. The inferred low viscosity of this layer is consistent with the development of climatically forced crustal flow in Southern Tibet.

  12. Relaxation of compensated topography and the evolution of crustal plateaus on Venus

    Science.gov (United States)

    Nunes, Daniel Cahn; Phillips, Roger J.; Brown, C. David; Dombard, Andrew J.

    2004-01-01

    Crustal plateaus, dominant physiographic features on Venus, likely originate through dynamic mantle processes, although a debate exists on whether they formed by mantle upwellings or downwellings. Regardless of the mode of formation, several observations led to the hypothesis that viscous relaxation may be the driving force behind the apparent evolutionary sequence from a high-standing plateau to a low-standing plateau with elevated margins. We apply analytic and finite element models to test this hypothesis for isostatically compensated topography, as modeling of gravity data suggests that crustal plateaus are presently supported by crustal roots. Geotherm values combined with a surface temperature of 740 K preclude relaxation within 109 years, while geotherm values >=20 K km-1 can yield relaxation times of 108 years or less. Hence significant relaxation requires hot conditions in order to occur within the appropriate 1-Gyr timescale set by crustal plateau ages. We also show that a compensated plateau can either retain its shape as it relaxes or become more domical in appearance. Mantle temperatures plateau and produces domical relaxed profiles. Higher temperatures lead to a relatively inviscid mantle and relaxation that is largely insensitive to topographic wavelength, thus preserving the original topographic shape during relaxation. In either case, relaxation of compensated plateaus does not yield elevated rims. We propose that the state of compensation must be considered variable.

  13. New images of the crustal structure beneath eastern Tibet from a high-density seismic array

    Science.gov (United States)

    Liu, Zhen; Tian, Xiaobo; Gao, Rui; Wang, Gaochun; Wu, Zhenbo; Zhou, Beibei; Tan, Ping; Nie, Shitan; Yu, Guiping; Zhu, Gaohua; Xu, Xiao

    2017-12-01

    An east-west trending, high-density seismic array was deployed along the eastern margin of the Tibetan Plateau to investigate its eastward expansion. The 160 km long array spans the Ruoergai basin, Minjiang fault, Minshan Mountains, Tazang fault, and West Qinling. The array included 330 short-period seismographs spaced at 500 m intervals, which recorded teleseismic 3-component waveforms over a one month period. P-wave receiver functions calculated from 35 teleseismic events provided an image of crustal structure. The results show a massive thrust nappe structure around the Minshan Mountains and beneath the Minjiang fault. We suggest that this nappe formed after the closure of the Paleo-Tethyan ocean. The resultant Triassic thrusting contributed to partial uplift of the eastern Ruoergai basin and the Minshan Mountains in middle-to-late Miocene time. Receiver function images show that the Tazang fault is a crustal-scale rupture cutting across the Moho. The western Tazang fault appears as a nearly vertical strike-slip fault accommodating left lateral shear at the terminus of the eastern Kunlun fault. After clockwise rotation from an approximate east-west orientation to a nearly north-south orientation, the eastern Tazang fault became a west-dipping thrust fault, which caused crustal thickening beneath the Minshan Mountains and the West Qinling. Our results suggest that late Cenozoic uplift of the eastern margin of the plateau is produced by eastward overthrusting and crustal shortening, processes that absorbed slip along the Tazang and Kunlun faults.

  14. High resolution regional crustal models from irregularly distributed data: application to Asia and adjacent areas

    NARCIS (Netherlands)

    Stolk, W.; Kaban, M.K.; Beekman, F.; Tesauro, M.; Mooney, W.D.; Cloetingh, S.

    2013-01-01

    We propose a new methodology to obtain crustal models in areas where data is sparse and data spreading is heterogeneous. This new method involves both interpolating the depth to the Moho discontinuity between observations and estimating a velocity–depth curve for the crust at each interpolation

  15. Crustal thickness, discontinuity depth, and upper mantle structure beneath southern Africa: constraints from body wave conversions

    NARCIS (Netherlands)

    Stankiewicz, Jacek; Che, Sébastien; Hilst, R.D. van der; Wit, Maarten J. de

    2002-01-01

    The technique of receiver function analysis is applied to the study of crustal and upper mantle structures beneath the Kaapvaal craton in southern Africa and its surroundings. Seismic data were recorded by the seismic array of 82 sites deployed from April 1997 to April 1999 across southern Africa,

  16. A crustal thickness map of Africa derived from a global gravity field model using Euler deconvolution

    NARCIS (Netherlands)

    Tedla, G.E.; Meijde, M. van der; Nyblade, A.A.; Meer, F.D. van der

    2011-01-01

    We develop a new continental scale crustal model for Africa by modelling the free-air gravity anomaly EIGEN-GL04C, which was developed from 30 months of GRACE Level 1B data covering the period from 2003 February to 2005 July, and surface gravity data from seven different sources. From this gravity

  17. Global maps of the CRUST 2.0 crustal components stripped gravity disturbances

    NARCIS (Netherlands)

    Tenzer, R.; Hamayun, K.; Vajda, P.

    2009-01-01

    We use the CRUST 2.0 crustal model and the EGM08 geopotential model to compile global maps of the gravity disturbances corrected for the gravitational effects (attractions) of the topography and of the density contrasts of the oceans, sediments, ice, and the remaining crust down to the Moho

  18. The Crustal Thickness of the Philippine Sea Plate Derived from Gravity Data

    Directory of Open Access Journals (Sweden)

    Horng-Yuan Yen

    2015-01-01

    Full Text Available We constructed a new free-air gravity anomaly map of the Philippine Sea Plate (PSP using ship-tracked gravity data from the National Geophysical Data Center (NGDC. Our results show that the isogals trend correlates well with the tectonic structures in the PSP. After removing the gravity induced by sea water from the free-air gravity data, we obtained the regional Bouguer gravity anomaly, which is later used to compute the Moho geometry in the PSP by applying the Parker-Oldenburg iterative method. Our results indicate that in the southern part of the West Philippine Basin (WPB the crustal thickness is nearly homogeneous with a value of about 5 km, which implies that the WPB is quite stable. The low-amplitude and near-zero free-air gravity anomalies clearly indicate that the whole WPB, except at trenches and island arcs, is nearly in a state of isostatic equilibrium. The average crustal thickness of the Palau Kyushu Ridge (PKR is more than 10 km. In the eastern PSP the crustal thickness gradually increases eastward. Our results also imply that a relatively thin and low density mantle exists beneath the Parece Vela Basin (PVB as a consequence of back-arc spreading and serpentinized upwells of the thin crustal thickness.

  19. Existence of torsional surface waves in an earth's crustal layer lying ...

    Indian Academy of Sciences (India)

    This paper aims to study the dispersion of torsional surface waves in a crustal layer being sandwiched between a rigid boundary plane and a sandy mantle. In the mantle, rigidity and initial stress vary linearly while density remains constant. Dispersion relation has been deduced in a closed form by means of variable ...

  20. Crustal thickness mapping in Raipur–Katni area of Narmada–Son ...

    Indian Academy of Sciences (India)

    is seismically active and geologically complex with different geological formations. Magnetic data divides the area into two ... era (Ravi Shanker 1988). NSL is a sub-crustal fea- .... Figure 1. Map of the surface geology with various formations along with Narmada, Son and Ken Rivers (after Geological. Survey of India 1993).

  1. Crustal Structure Beneath India and Tibet: New Constraints From Inversion of Receiver Functions

    Science.gov (United States)

    Singh, Arun; Ravi Kumar, M.; Mohanty, Debasis D.; Singh, Chandrani; Biswas, Rahul; Srinagesh, D.

    2017-10-01

    The Indian subcontinent comprises geological terranes of varied age and structural character. In this study, we provide new constraints to existing crustal models by inverting the P-to-s receiver functions (RFs) at 317 broadband seismic stations. Inversion results fill crucial gaps in existing velocity models (CRUST1.0 and SEAPS) by capturing regions which are less represented. The final model produced is much more heterogeneous and is able to capture the structural variations between closely spaced seismic stations. In comparison to the global models, major differences are seen for seismic stations located over various rift zones (e.g., Godavari, Narmada, and Cambay) and those close to the coastal regions where transition from oceanic to continental crust is expected to create drastic changes in the crustal configuration. Seismic images are produced along various profiles using 49,682 individual RFs recorded at 442 seismic stations. Lateral variations captured using migrated images across the Himalayan collisional front revealed the hitherto elusive southern extent of the Moho and intracrustal features south of the Main Central Thrust (MCT). Poisson's ratio and crustal thickness estimates obtained using H-k stacking technique and inversion of RFs are grossly similar lending credence to the robustness of inversions. An updated crustal thickness map produced using 1,525 individual data points from controlled source seismics and RFs reveals a (a) thickened crust (>55 km) at the boundary of Dharwar Craton and Southern Granulite Terrain, (b) clear difference in crustal thickness estimates between Eastern Dharwar Craton and Western Dharwar Craton, (c) thinner crust beneath Cambay Basin between southwest Deccan Volcanic Province and Delhi-Aravalli Fold Belt, (d) thinner crust (40 km) beneath paleorift zones like Narmada Son Lineament and Godavari Graben, and (f) very thick crust beneath central Tibet (>65 km) with maximum lateral variations along the Himalayan collision

  2. Reconstructing the Mid-Tertiary Southwestern North America Cordilleran Crust: Crustal Anisotropy

    Science.gov (United States)

    Porter, R. C.; Zandt, G.; McQuarrie, N.; Gilbert, H. J.; Hacker, B. R.

    2009-12-01

    The deployment of EarthScope USArray stations provides researchers with unprecedented quantities and coverage of publicly available seismic data that can be combined with other techniques to better understand the tectonic evolution of western North America. We utilize the receiver function method to map the crustal thickness and investigate the occurrence and orientation of lower crustal anisotropy for the southwestern U.S. Using the tectonic reconstruction of McQuarrie and Wernicke (2005), we then reconstruct the location and orientation of the anisotropy back to 36 Ma. We have completed the reconstruction for central and southern California, and found a dominant SW-NE oriented trend that we interpret as a fossilized fabric within underplated schists created from top-to-southwest sense of shear that existed along the length of coastal California during pre-transform, early-Tertiary subduction. Initial results from the Basin and Range show a generally consistent E-W anisotropy trend within the northern and central Basin and Range, orthogonal to modern faulting and mountain ranges. Within this area there is a correlation of generally stronger crustal anisotropy and thinner crust in the eastern Basin and Range. In the southern Basin and Range we observe more scatter in our anisotropy results, with a majority of stations exhibiting either a SW-NE or NNW-SSE orientation. Despite the variability in results, most anisotropy orientations appear to be orthogonal to nearby mountain ranges. These observations suggest that Tertiary extension in the Basin and Range is producing a lower crustal zone of anisotropy throughout the province. We are currently working to expand on these results by integrating elasticity tensors calculated from electron-backscatter diffraction measurements of samples of lower crustal rocks from the southwestern U.S.

  3. Three-dimensional seismic model of crustal structure in Southern Norway

    Science.gov (United States)

    Loidl, B.; Behm, M.; Thybo, H.; Stratford, W.

    2014-03-01

    New insights in crustal structure in southern Norway are given by combining stacking techniques and traveltime tomography of 3-D wide-angle reflection/refraction data. The Magnus Rex crustal scale wide-angle refraction/reflection data set in Southern Norway covers an area of 400 km × 430 km where 716 receivers on three profiles recorded seismic waves from 26 explosive sources. Previous data analysis focused on 2-D interpretation along the profiles. Here we extract additional P-wave velocity information by inverting inline and cross-line data simultaneously. We combine stacking routines, traveltime tomography, and interpolation algorithms to the high quality inline and cross-line data. A smooth 3-D crustal velocity model is inverted from traveltimes of diving Pg waves with similar results for two initial models. Initial models include a 1-D average model and an interpolated 3-D model based on robust, local 1-D velocity-depth functions derived from CMP-sorted and stacked records. The depth to Moho is determined from reflected waves (PmP) by traditional exploration seismology processing routines (CMP sorting, NMO correction, stacking, depth conversion). We find that this combination of stacking methods and traveltime tomography is well suited to exploit sparse 3-D wide-angle data. The results along the profiles are similar to the earlier 2-D models and the 3-D velocity model shows little lateral variation. The crust in SW Norway is generally 35-40 km thick and has relatively low average velocity, as it lacks the characteristic high-velocity lower crust, otherwise observed in the Baltic Shield. However, the Oslo Graben is characterized by high crustal velocities and a slightly elevated Moho. Our results suggest that this crustal structure continues towards the north along the strike of the graben.

  4. Evaluation of six NEHRP B/C crustal amplification models proposed for use in western North America

    Science.gov (United States)

    Boore, David; Campbell, Kenneth W.

    2016-01-01

    We evaluate six crustal amplification models based on National Earthquake Hazards Reduction Program (NEHRP) B/C crustal profiles proposed for use in western North America (WNA) and often used in other active crustal regions where crustal properties are unknown. One of the models is based on an interpolation of generic rock velocity profiles previously proposed for WNA and central and eastern North America (CENA), in conjunction with material densities based on an updated velocity–density relationship. A second model is based on the velocity profile used to develop amplification factors for the Next Generation Attenuation (NGA)‐West2 project. A third model is based on a near‐surface velocity profile developed from the NGA‐West2 site database. A fourth model is based on velocity and density profiles originally proposed for use in CENA but recently used to represent crustal properties in California. We propose two alternatives to this latter model that more closely represent WNA crustal properties. We adopt a value of site attenuation (κ0) for each model that is either recommended by the author of the model or proposed by us. Stochastic simulation is used to evaluate the Fourier amplification factors and their impact on response spectra associated with each model. Based on this evaluation, we conclude that among the available models evaluated in this study the NEHRP B/C amplification model of Boore (2016) best represents median crustal amplification in WNA, although the amplification models based on the crustal profiles of Kamai et al. (2013, 2016, unpublished manuscript, see Data and Resources) and Yenier and Atkinson (2015), the latter adjusted to WNA crustal properties, can be used to represent epistemic uncertainty.

  5. Sink or Swim? the Role of Intracrustal Differentiation in the Generation of Compositional Diversity and Crustal Delamination in the Archean

    Science.gov (United States)

    VanTongeren, J. A.; Herzberg, C. T.; Kaus, B.; Johnson, T. E.; Brown, M.

    2014-12-01

    Significant debate exists regarding the processes of crustal formation and stabilization in the Archean, with some researchers advocating for continuous subduction-like processes throughout earth history, and others advocating crustal recycling by lithospheric delamination or 'drip tectonics'. Much of the debate hinges on whether Archean mantle potential temperatures (Tp) were significantly hotter than the present day. The rock record of non-arc Archean primary magma compositions (Herzberg et al., 2010) has been used to infer higher ambient Tp (Tp = 1500-1650C) during the Archean, causing high melt fractions during decompression melting, and leading to extreme primary (oceanic) crustal thicknesses of 30-40 km (Herzberg and Rudnick, 2012). Such crustal thicknesses might inhibit subduction, in which case an alternative mechanism of crustal recycling would be required. In their recent paper, Johnson et al. (2014) showed that at Tp > 1500C, the lower portions of a thick homogenous Archean primary crust generated would be density unstable with respect to the ambient mantle. Additionally, they showed that given realistic rheological constraints, large-scale lower crustal delamination is a very efficient crustal recycling mechanism at Tp >1600C. The Archean crust, however, is likely to be internally differentiated. Here we present pMELTS and Perple_X modeling results on the intracrustal differentiation of Archean primary crust, resulting in the formation of TTG-like granitoids in the upper crust and a lower crust dominated by clinopyroxenite. Using the composition and density profiles generated by intracrustal differentiation, our geodynamic modeling extends the Tp over which efficient crustal delamination will occur to lower values, consistent with those likely throughout the Archean. Efficient crustal differentiation and delamination of dense mafic residues throughout the Archean may explain the apparent paucity of mafic lithologies relative to TTGs that characterize

  6. Crustal structure of the Siberian craton and the West Siberian basin: An appraisal of existing seismic data

    DEFF Research Database (Denmark)

    Cherepanova, Yulia; Artemieva, Irina M.; Thybo, Hans

    2013-01-01

    We present a digital model SibCrust of the crustal structure of the Siberian craton (SC) and the West Siberian basin (WSB), based on all seismic profiles published since 1960 and sampled with a nominal interval of 50 km. Data quality is assessed and quantitatively assigned to each profile based...... on acquisition and interpretation method and completeness of crustal model. The database represents major improvement in coverage and resolution and includes depth to Moho, thickness and average P-wave velocity of five crustal layers (sediments, and upper, middle, lower, and lowermost crust) and Pn velocity...

  7. Upper-crustal velocity structure along 150 km of the Mendeleev Ridge from tomographic inversion of long-offset refraction data collected during HLY0602

    Science.gov (United States)

    Vermeesch, P. M.; van Avendonk, H. J.; Lawver, L. A.

    2007-12-01

    In the summer of 2006 we acquired a unique seismic refraction data set on the Chukchi Borderlands and Mendeleev Ridge utilizing USCGC Healy and two helicopters. The array on the Mendeleev Ridge consisted of 14 instrument sites with 12 km spacing between instruments. On every site we deployed a Sea-Ice Seismometer (S- IS) especially designed for this experiment in the ice-covered part of the Arctic Ocean. Each S-IS contained a vertical component geophone that was buried in the ice and a hydrophone that was hanging from the ice edge in the water. From the 14 instrument sites, 10 contained useful data with refracted crustal arrivals up to offsets of 40 km. Because of extensive drifting of the receivers (40 km in 5 days and containing numerous loops), and because of the irregular geometry of airgun shots due to the problems of sailing through ice-covered seas, a 3D ray-shooting code was developed to calculate ray paths within a 3D velocity model that extends along 150 km in the X- direction and along 35 km in the Y-direction. Using the velocity model proposed by Lebedeva-Ivanova et al. (2006) we observe that the maximum depth of our calculated ray paths is 11 km below sealevel. Using all the available data, the Root Mean Square (RMS) difference between observed and calculated travel-times is of the order of 500 ms. Initially a simple 1D travel-time inversion was developed to constrain the velocity structure of the basement underneath a layer of water (3D) and a layer of sediment (1D). This inversion was carried out on 2 pairs of receivers: one pair in the NNE and one more towards the SSW part of the line. Inversion of S-IS 45N-42 (NNE) results in a model with a velocity of 5.5 km s-1 at the top of the basement, slowly increasing to a velocity of 5.7 km s-1 at 3 km below the top of the basement (RMS = 117 ms). Inversion of S-IS 49-45S (SSW) results in a model with a velocity of 4.8 km s-1 at the top of the basement, increasing to a velocity of 5.9 km s-1 at 3 km below

  8. Mechanisms and Magnitude of Cenozoic Crustal Extension in the Vicinity of Lake Mead, Nevada and the Beaver Dam Mountains, Utah: Geochemical, Geochronological,Thermochronological and Geophysical Constraints

    Science.gov (United States)

    Almeida, Rafael V.

    The central Basin and Range Province of Nevada and Utah was one of the first areas in which the existence of widespread low-angle normal faults or detachments was first recognized. The magnitude of associated crustal extension is estimated by some to be large, in places increasing original line lengths by as much as a factor of four. However, rock mechanics experiments and seismological data cast doubt on whether these structures slipped at low inclination in the manner generally assumed. In this dissertation, I review the evidence for the presence of detachment faults in the Lake Mead and Beaver Dam Mountains areas and place constraints on the amount of extension that has occurred there since the Miocene. Chapter 1 deals with the source-provenance relationship between Miocene breccias cropping out close to Las Vegas, Nevada and their interpreted source at Gold Butte, currently located 65 km to the east. Geochemical, geochronological and thermochronological data provide support for that long-accepted correlation, though with unexpected mismatches requiring modification of the original hypothesis. In Chapter 2, the same data are used to propose a refinement of the timing of ~1.45 Ga anorogenic magmatism, and the distribution of Proterozoic crustal boundaries. Chapter 3 uses geophysical methods to address the subsurface geometry of faults along the west flank of the Beaver Dam Mountains of southwestern Utah. The data suggest that the range is bounded by steeply inclined normal faults rather than a regional-scale detachment fault. Footwall folding formerly ascribed to Miocene deformation is reinterpreted as an expression of Cretaceous crustal shortening. Fission track data presented in Chapter 4 are consistent with mid-Miocene exhumation adjacent to high-angle normal faults. They also reveal a protracted history dating back to the Pennsylvanian-Permian time, with implications for the interpretation of other basement-cored uplifts in the region. A key finding of this

  9. Sediment and Crustal Shear Velocity Structure offshore New Zealand from Seafloor Compliance, Receiver Functions and Rayleigh Wave Dispersion

    Science.gov (United States)

    Ball, J. S.; Sheehan, A. F.; Stachnik, J. C.; Lin, F.; Collins, J. A.

    2013-12-01

    We have developed a joint Monte Carlo inversion of teleseismic receiver functions, seafloor compliance, and Rayleigh wave dispersion and apply it here to ocean bottom seismic (OBS) data from offshore New Zealand. With this method we estimate sediment and crustal thickness and shear velocity structure beneath the Bounty Trough and the Tasman Sea flanking the South Island of New Zealand. Teleseismic receiver functions and surface wave dispersion measurements provide complementary constraints on shear velocity structure and interface depths beneath seismic stations. At ocean bottom seismic (OBS) stations the interpretation of these measurements is complicated by strong sediment reverberations that obscure deeper impedance contrasts such as the Moho. In principle, the seafloor's response to ocean loading from infragravity waves (seafloor compliance) can be used to determine shallow shear velocity information. This velocity information can subsequently be used to better model the receiver function reverberations, allowing deeper interfaces of tectonic interest to be resolved. Data for this study were acquired in 2009-2010 by the Marine Observations of Anisotropy Near Aotearoa (MOANA) experiment, which deployed 30 broadband OBS and differential pressure gauges (DPGs) off the South Island of New Zealand. High-frequency (5Hz) receiver functions were estimated using multitaper cross-correlation for events in a 30-90 degree epicentral distance range. Coherence-weighted stacks binned by epicentral distance were produced in the frequency domain to suppress noise. Seafloor compliance was measured using multitaper pressure and acceleration spectra averaged from 120 days of continuous data without large transient events. Seafloor compliance measurements on the order of 10-9 Pa-1 are sensitive to shear velocity structure in the uppermost 5km of the crust and sediments. Rayleigh dispersion measurements were obtained at periods of 6-27s from ambient noise cross correlation. Sediment

  10. Polyvinyl chloride as a multimodal tissue-mimicking material with tuned mechanical and medical imaging properties.

    Science.gov (United States)

    Li, Weisi; Belmont, Barry; Greve, Joan M; Manders, Adam B; Downey, Brian C; Zhang, Xi; Xu, Zhen; Guo, Dongming; Shih, Albert

    2016-10-01

    The mechanical and imaging properties of polyvinyl chloride (PVC) can be adjusted to meet the needs of researchers as a tissue-mimicking material. For instance, the hardness can be adjusted by changing the ratio of softener to PVC polymer, mineral oil can be added for lubrication in needle insertion, and glass beads can be added to scatter acoustic energy similar to biological tissue. Through this research, the authors sought to develop a regression model to design formulations of PVC with targeted mechanical and multimodal medical imaging properties. The design of experiment was conducted by varying three factors-(1) the ratio of softener to PVC polymer, (2) the mass fraction of mineral oil, and (3) the mass fraction of glass beads-and measuring the mechanical properties (elastic modulus, hardness, viscoelastic relaxation time constant, and needle insertion friction force) and the medical imaging properties [speed of sound, acoustic attenuation coefficient, magnetic resonance imaging time constants T1 and T2, and the transmittance of the visible light at wavelengths of 695 nm (Tλ695) and 532 nm (Tλ532)] on twelve soft PVC samples. A regression model was built to describe the relationship between the mechanical and medical imaging properties and the values of the three composition factors of PVC. The model was validated by testing the properties of a PVC sample with a formulation distinct from the twelve samples. The tested soft PVC had elastic moduli from 6 to 45 kPa, hardnesses from 5 to 50 Shore OOO-S, viscoelastic stress relaxation time constants from 114.1 to 191.9 s, friction forces of 18 gauge needle insertion from 0.005 to 0.086 N/mm, speeds of sound from 1393 to 1407 m/s, acoustic attenuation coefficients from 0.38 to 0.61 (dB/cm)/MHz, T1 relaxation times from 426.3 to 450.2 ms, T2 relaxation times from 21.5 to 28.4 ms, Tλ695 from 46.8% to 92.6%, and Tλ532 from 41.1% to 86.3%. Statistically significant factors of each property were identified. The

  11. Crustal Deformation Field Around Rift Zone In Southeastern Afar Derived From Jers-1/in-sar

    Science.gov (United States)

    Ozawa, T.; Nogi, Y.; Shibuya, K.

    Afar is one of the major active rift zones recognized on the ground and located around the triple junction of Arabia, Somalia and Nubian plates. Afar is one of the major rift zones recognized on the ground. The crustal deformation of Afar has been deduced from paleomagnetism, geology and seismology by many scientists. The current crustal deformation must be detected by geodetic measurements. Ruegg et al. (J. Geophys. Res., 1984) showed the crustal deformation across the Asal-Ghoubbet rift with rate of about 60 mm/yr extension derived from triangulation and trilateration. Walpersdorf et al. (J. Geodyn., 1999) show the opening between South Djibouti and Yemen with rate of 16 mm/yr by GPS surveys. Denser observations are required for detailed crustal deformation, however it is difficult to construct such observation network because of harsh environment. The geodetic application of remote sensing is useful in this region, and we apply JERS-1 SAR interferometry in southeastern Afar, which is one of the most active deformation area. In this study, we use six SAR scenes observed from 1996/5/20 to 1997/5/7, and generate five interferograms; these repeat cycles are 88 (2 pairs), 176, 264, 352 days. First, we generate the digital elevation model (DEM) from two 88 repeat cycle pairs applying the multiple pass SAR interferometry method by Kwok and Fahnestock (IEEE Trans. Geosci. Remote Sensing, 1996). Next, the topographic fringes of all pairs are removed using the DEM. The crustal deformation derived from SAR interferometry increases with expanding repeat cycle. Finally, the velocity field is estimated by fitting to linear trend for each pixel. The spreading rate of Asal-Ghoubbet rift derived from SAR interferometry is good agreement with that by Ruegg et al. (J. Geophys. Res., 1984). We can see the crustal deformation with the subsidence sense in the west of Asal-Ghoubbet rift. This suggests that the extension is distinguished in this area. The subsidence sense deformation

  12. An Inversion of Gravity and Topography for Mantle and Crustal Structure on Mars

    Science.gov (United States)

    Kiefer, Walter S.; Bills, Bruce G.; Nerem, R. Steven

    1996-01-01

    Analysis of the gravity and topography of Mars presently provides our primary quantitative constraints on the internal structure of Mars. We present an inversion of the long-wavelength (harmonic degree less than or equal to 10) gravity and topography of Mars for lateral variations of mantle temperature and crustal thickness. Our formulation incorporates both viscous mantle flow (which most prior studies have neglected) and isostatically compensated density anomalies in the crust and lithosphere. Our nominal model has a 150-km-thick high-viscosity surface layer over an isoviscous mantle, with a core radius of 1840 km. It predicts lateral temperature variations of up to a few hundred degrees Kelvin relative to the mean mantle temperature, with high temperature under Tharsis and to a lesser extent under Elysium and cool temperatures elsewhere. Surprisingly, the model predicts crustal thinning beneath Tharsis. If correct, this implies that thinning of the crust by mantle shear stresses dominates over thickening of the crust by volcanism. The major impact basins (Hellas, Argyre, Isidis, Chryse, and Utopia) are regions of crustal thinning, as expected. Utopia is also predicted to be a region of hot mantle, which is hard to reconcile with the surface geology. An alternative model for Utopia treats it as a mascon basin. The Utopia gravity anomaly is consistent with the presence of a 1.2 to 1.6 km thick layer of uncompensated basalt, in good agreement with geologic arguments about the amount of volcanic fill in this area. The mantle thermal structure is the dominant contributor to the observed geoid in our inversion. The mantle also dominates the topography at the longest wavelengths, but shorter wavelengths (harmonic degrees greater than or equal to 4) are dominated by the crustal structure. Because of the uncertainty about the appropriate numerical values for some of the model's input parameters, we have examined the sensitivity of the model results to the planetary

  13. Numerical model of crustal accretion and cooling rates of fast-spreading mid-ocean ridges

    Directory of Open Access Journals (Sweden)

    P. Machetel

    2013-10-01

    Full Text Available We designed a thermo-mechanical numerical model for fast-spreading mid-ocean ridge with variable viscosity, hydrothermal cooling, latent heat release, sheeted dyke layer, and variable melt intrusion possibilities. The model allows for modulating several accretion possibilities such as the "gabbro glacier" (G, the "sheeted sills" (S or the "mixed shallow and MTZ lenses" (M. These three crustal accretion modes have been explored assuming viscosity contrasts of 2 to 3 orders of magnitude between strong and weak phases and various hydrothermal cooling conditions depending on the cracking temperatures value. Mass conservation (stream-function, momentum (vorticity and temperature equations are solved in 2-D cartesian geometry using 2-D, alternate direction, implicit and semi-implicit finite-difference scheme. In a first step, an Eulerian approach is used solving iteratively the motion and temperature equations until reaching steady states. With this procedure, the temperature patterns and motions that are obtained for the various crustal intrusion modes and hydrothermal cooling hypotheses display significant differences near the mid-ocean ridge axis. In a second step, a Lagrangian approach is used, recording the thermal histories and cooling rates of tracers travelling from the ridge axis to their final emplacements in the crust far from the mid-ocean ridge axis. The results show that the tracer's thermal histories are depending on the temperature patterns and the crustal accretion modes near the mid-ocean ridge axis. The instantaneous cooling rates obtained from these thermal histories betray these discrepancies and might therefore be used to characterize the crustal accretion mode at the ridge axis. These deciphering effects are even more pronounced if we consider the average cooling rates occurring over a prescribed temperature range. Two situations were tested at 1275–1125 °C and 1050–850 °C. The first temperature range covers mainly the

  14. Crustal composition in the Hidaka Metamorphic Belt estimated from seismic velocity by laboratory measurements

    Science.gov (United States)

    Yamauchi, K.; Ishikawa, M.; Sato, H.; Iwasaki, T.; Toyoshima, T.

    2015-12-01

    To understand the dynamics of the lithosphere in subduction systems, the knowledge of rock composition is significant. However, rock composition of the overriding plate is still poorly understood. To estimate rock composition of the lithosphere, it is an effective method to compare the elastic wave velocities measured under the high pressure and temperature condition with the seismic velocities obtained by active source experiment and earthquake observation. Due to an arc-arc collision in central Hokkaido, middle to lower crust is exposed along the Hidaka Metamorphic Belt (HMB), providing exceptional opportunities to study crust composition of an island arc. Across the HMB, P-wave velocity model has been constructed by refraction/wide-angle reflection seismic profiling (Iwasaki et al., 2004). Furthermore, because of the interpretation of the crustal structure (Ito, 2000), we can follow a continuous pass from the surface to the middle-lower crust. We corrected representative rock samples from HMB and measured ultrasonic P-wave (Vp) and S-wave velocities (Vs) under the pressure up to 1.0 GPa in a temperature range from 25 to 400 °C. For example, the Vp values measured at 25 °C and 0.5 GPa are 5.88 km/s for the granite (74.29 wt.% SiO2), 6.02-6.34 km/s for the tonalites (66.31-68.92 wt.% SiO2), 6.34 km/s for the gneiss (64.69 wt.% SiO2), 6.41-7.05 km/s for the amphibolites (50.06-51.13 wt.% SiO2), and 7.42 km/s for the mafic granulite (50.94 wt.% SiO2). And, Vp of tonalites showed a correlation with SiO2 (wt.%). Comparing with the velocity profiles across the HMB (Iwasaki et al., 2004), we estimate that the lower to middle crust consists of amphibolite and tonalite, and the estimated acoustic impedance contrast between them suggests an existence of a clear reflective boundary, which accords well to the obtained seismic reflection profile (Iwasaki et al., 2014). And, we can obtain the same tendency from comparing measured Vp/Vs ratio and Vp/Vs ratio structure model

  15. Dispersion characteristics of the flexural wave assessed using low frequency (50-150kHz) point-contact transducers: A feasibility study on bone-mimicking phantoms.

    Science.gov (United States)

    Kassou, Koussila; Remram, Youcef; Laugier, Pascal; Minonzio, Jean-Gabriel

    2017-11-01

    Guided waves-based techniques are currently under development for quantitative cortical bone assessment. However, the signal interpretation is challenging due to multiple mode overlapping. To overcome this limitation, dry point-contact transducers have been used at low frequencies for a selective excitation of the zeroth order anti-symmetric Lamb A0 mode, a mode whose dispersion characteristics can be used to infer the thickness of the waveguide. In this paper, our purpose was to extend the technique by combining a dry point-contact transducers approach to the SVD-enhanced 2-D Fourier transform in order to measure the dispersion characteristics of the flexural mode. The robustness of our approach is assessed on bone-mimicking phantoms covered or not with soft tissue-mimicking layer. Experiments were also performed on a bovine bone. Dispersion characteristics of measured modes were extracted using a SVD-based signal processing technique. The thickness was obtained by fitting a free plate model to experimental data. The results show that, in all studied cases, the estimated thickness values are in good agreement with the actual thickness values. From the results, we speculate that in vivo cortical thickness assessment by measuring the flexural wave using point-contact transducers is feasible. However, this assumption has to be confirmed by further in vivo studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Discrimination of Umami Tastants Using Floating Electrode-Based Bioelectronic Tongue Mimicking Insect Taste Systems.

    Science.gov (United States)

    Lee, Minju; Jung, Je Won; Kim, Daesan; Ahn, Young-Joon; Hong, Seunghun; Kwon, Hyung Wook

    2015-12-22

    We report a floating electrode-based bioelectronic tongue mimicking insect taste systems for the detection and discrimination of umami substances. Here, carbon nanotube field-effect transistors with floating electrodes were hybridized with nanovesicles containing honeybee umami taste receptor, gustatory receptor 10 of Apis mellifera (AmGr10). This strategy enables us to discriminate between l-monosodium glutamate (MSG), best-known umami tastant, and non-umami substances with a high sensitivity and selectivity. It could also be utilized for the detection of MSG in liquid food such as chicken stock. Moreover, we demonstrated the synergism between MSG and disodium 5'-inosinate (IMP) for the umami taste using this platform. This floating electrode-based bioelectronic tongue mimicking insect taste systems can be a powerful platform for various applications such as food screening, and it also can provide valuable insights on insect taste systems.

  17. Polydimethylsiloxane tissue-mimicking phantoms for quantitative optical medical imaging standards

    Science.gov (United States)

    Hwang, Jeeseong; Kim, Hyun-Jin; Lemaillet, Paul; Wabnitz, Heidrun; Grosenick, Dirk; Yang, Lin; Gladytz, Thomas; McClatchy, David; Allen, David; Briggman, Kimberly; Pogue, Brian

    2017-03-01

    We report on a procedure to build and characterize solid tissue-mimicking phantoms of polydimethylsiloxane (PDMS) polymers. Controlled inclusion of light scattering titanium dioxide (TiO2) nanoparticles enables the creation of phantoms having tunable light scattering properties with reduced scattering coefficients consistent across different measurement platforms including an integrating sphere and a time-resolved diffuse optical spectroscopic system. Backscatter confocal microscopy is also used to characterize the shape and distribution of included TiO2 particles. The double integrating sphere and time-resolved diffuse spectroscopy were used to measure the reduced scattering coefficients of the phantoms. The results across different systems are in good agreement, suggesting that the PDMS/TiO2 composite is a promising tissue-mimicking material for developing standards useful to validate measurements by different devices for multiplatform and multi-laboratory tests.

  18. Self-assembled monolayer facilitates epithelial-mesenchymal interactions mimicking odontogenesis.

    Science.gov (United States)

    Muni, Tanvi; Mrksich, Milan; George, Anne

    2014-01-01

    Cell-cell interactions are vital for embryonic organ development and normal function of differentiated cells and tissues. In this study we have developed a self-assembled monolayer-based co-culture system to study tooth morphogenesis. Specifically, we designed a 2-D microenvironment present in the dental tissue by creating a well-structured, laterally organized epithelial and mesenchymal cell co-culture system by patterning the cell-attachment substrate. Chemical modifications were used to develop tunable surface patterns to facilitate epithelial-mesenchymal interactions mimicking the developing tooth. Such a design promoted interactions between monolayer's of the 2 cell types and provided signaling cues that resulted in cellular differentiation and mineralized matrix formation. Gene expression analysis showed that these co-cultures mimicked in-vivo conditions than monolayer cultures of a single cell type.

  19. Study of single-electron information-processing circuit mimicking foraging behavior of honeybee swarm

    Science.gov (United States)

    Tanabe, Toshihiko; Oya, Takahide

    2017-06-01

    A new single-electron (SE) circuit mimicking the foraging behavior of a honeybee swarm is proposed. Recently, a “nature-inspired” or “biomimetic” technology has been attracting attention for developing innovative functional systems applying emerging nanoscale devices. In particular, the foraging behavior of honeybees is focused on as an architecture for a SE circuit. Honeybees show two foraging behaviors, namely, a probability search and a “waggle dance” (sharing information). By combining these behaviors, it can be considered that the foraging behavior is a unique information-processing act. For constructing a new system, a SE circuit mimicking the behavior was designed, constructed, and simulated. The SE circuit was constructed by assuming that the information that honeybees share corresponds to the operation of the circuit. The results of the simulation confirmed that the SE circuit mimics the information-sharing behavior of honeybees. Namely, the proposed honeybee-inspired SE circuit can perform functional information processing.

  20. Brown tumor mimicking maxillary sinus mucocele as the first manifestation of primary hyperparathyroidism

    DEFF Research Database (Denmark)

    Guldfred, Liviu-Adelin; Daugaard, Søren; von Buchwald, Christian

    2012-01-01

    We describe the first case of brown tumor mimicking a maxillary sinus mucocele as the first manifestation of the patient's primary hyperparathyroidism. A 34-year old woman presented with a 14 days history of elevation of the right orbit, retrobulbar pain and cheek anesthesia. The CT and MR...... evaluation showed a mass, initially described as mucocele of the right maxillary sinus. The laboratory studies revealed hyperparathyroidism. The patient underwent acute surgery, and the mass appeared clinically as mucocele. The histological examination of the resected lesion revealed changes representing...... either giant cell granuloma or brown tumor. The finding of hyperparathyroidism confirmed the diagnosis of brown tumor. To our knowledge, this is the first report of cystic brown tumor mimicking a mucocele of the maxillary sinus....

  1. Acute Cerebellar Ataxia Associated with Anti-glutamic Acid Decarboxylase Antibodies Mimicking Miller Fisher Syndrome.

    Science.gov (United States)

    Nakamura, Yoshitsugu; Nakajima, Hideto; Hosokawa, Takafumi; Yamane, Kazushi; Ishida, Shimon; Kimura, Fumiharu

    2018-01-15

    We herein report the case of a 53-year-old man with cerebellar ataxia with anti-glutamic acid decarboxylase antibody (GAD-Ab) who mimicked Miller Fisher syndrome (MFS). He developed ophthalmoplegia, diplopia, and gait ataxia for one week. The serum and cerebrospinal fluid GAD-Ab titers were greatly increased, and the GAD-Ab index suggesting intrathecal antibody synthesis was elevated, while GQ1b-Ab was negative. After steroid pulse therapy and following prednisolone, his symptoms dramatically improved over the course of 11 months with the simultaneous decline of GAD-Ab titers. This case indicates that cerebellar ataxia with GAD-Ab can present with acute neurological findings mimicking MFS, and that steroid therapy has an excellent therapeutic effect.

  2. A High-Grade Chondrosarcoma of Calcaneum Mimicking as a Benign Pathology: Delayed Diagnosis and Management.

    Science.gov (United States)

    Baba, Muzamil Ahmad; Nazir, Naila; Shabeer, Maajid; Mir, Bashir Ahmed; Kawoosa, Altaf Ahmad

    2016-10-01

    This case is presented to highlight a rare case of chondrosarcoma of calcaneum in a young adult mimicking as a benign pathology and to highlight the diagnosis and early management of such cases to prevent complications and even death. Chondrosarcoma constitutes less than 10% of all primary malignancies of bone and occurs mostly in proximal locations such as pelvis, proximal femur, and proximal humerus. We present a case of high-grade chondrosarcoma at a very rare site, calcaneum of a 40-year-old male that was mimicking as a benign pathology. This case report highlights the importance of proper clinical examination, evaluation, and suspicion for benign occurring lesions to prevent complications related to a delay in diagnosis. Therapeutic, Level IV: Case study. © 2016 The Author(s).

  3. Design and Characterisation of Tissue-Mimicking Gel Phantoms for Diffusion Kurtosis Imaging

    CERN Document Server

    Portakal, Ziyafer Gizem; Spezi, Emiliano; Tuncel, Nina; Phillips, Jonathan

    2016-01-01

    The purpose of the study was to create tissue-mimicking gel phantoms appropriate for diffusion kurtosis imaging (DKI). Diffusion coefficients, including the well-known apparent diffusion coefficients (ADCs) and the diffusion coefficient based on the kurtosis model for the decay of the diffusion signal and (excess) kurtosis values were experimentally determined for the gelling agents of agar, agarose and polyvinyl alcohol (PVA) cryogel commonly used in multi-modal imaging. Although we observe an increase in kurtosis with the concentration of the gelling agents, the values obtained from diffusion-weighted magnetic resonance imaging (DW-MRI) were too low (under the expectations) to mimic the range of values reported in the literature for various healthy and diseased tissues. To create tissue-mimicking gels phantoms with more realistic kurtosis values, different concentrations of glass microbeads were added. Experimental characterisation showed that realistic kurtosis values for a range of tissues may be obtained...

  4. Primary Benign Intraosseous Meningioma on {sup 18}F-FDG PET/CT Mimicking Malignancy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Seong; Kim, Seok Hwi; Kim, Hyung Jin; Kang, Se Woong; Kim, Soo Jeong; Lee, Joo Hee; Hong, Sun Pyo; Cho, Young Seok; Choi, Joon Young [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

    2014-06-15

    We present a case of primary benign intraosseous meningioma in the sphenoid bone mimicking malignancy. A 44-year-old female patient who had a protruding right eye and headache came to our hospital. MRI showed a large, destructive, heterogeneously well-enhancing soft tissue mass in the right sphenoid bone suggesting malignancy. {sup 18}F-FDG PET/CT showed a hypermetabolic mass in the same site with an SUV{sub max} of 9.1 The pathological diagnosis by surgery revealed that this tumor was a WHO grade I transitional meningioma. This case suggests that primary benign intraosseous meningioma may show high {sup 18}F-FDG uptake mimicking a malignancy.

  5. Intense Microbubbles Mimicking Mobile Thrombus in a Patient with Prosthetic Mitral Valve

    Directory of Open Access Journals (Sweden)

    Fatma Yılmaz Coşkun

    2017-06-01

    Full Text Available Microbubbles have been presumed as gaseous emboli, which originate during mechanical heart valve closure, but are not seen in bioprosthetic valves. In this report, we presented a cluster of microbubbles mimicking mobile thrombus in a patient with mechanical mitral valve prosthesis. A 30-year-old female with a history of implanted mechanical valve at the mitral position underwent a routine examination. She was asymptomatic and her physical examination was unremarkable. Transthoracic echocardiography showed a mobile thrombus-like mass on the ventricular side of the prosthetic mitral valve moving into the left ventricular outflow tract. However, close examination of images indicated that the mass was in fact intense microbubbles mimicking thrombus. Intense mobile microbubbles can be misdiagnosed as a mobile thrombus. We recommend and underscore the importance of detailed echocardiographic examination in case of mobile mass to avoid misdiagnosis in patients with mechanical heart valves.

  6. Primary intraosseous squamous cell carcinoma mimicking periapical disease: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yoon Joo; Oh, Song Hee; Kang, Ju Han; Choi, Hwa Young; Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of); Yu, Jae June [Dept. of Oral and Maxillofacial Radiology, Kangdong Sacred Heart Hospital, Hallym Medical Center, Seoul (Korea, Republic of)

    2012-09-15

    Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare carcinoma, which arises within the jaws without connection to the oral mucosa and presumably develops from a remnant of odontogenic epithelium. We present a case of solid type PIOSCC in a 52-year-old male patient complaining of dull pain on his left lower molar. In this case, early stage PIOSCC mimicking a periapical lesion might lead to a one-year delay in treatment due to the misdiagnosis of osteomyelitis after extraction of the third molar. The clinical, radiological, and histologic features are described. In this case, there was initial radiographic evidence for PIOSCC mimicking a periapical lesion. Incautious radiographic interpretation and treatment procedures had delayed the correct diagnosis and resulted in extensive bony destruction during the patient's disease progression.

  7. Confining rigid balls by mimicking quadrupole ion trapping

    Science.gov (United States)

    Fan, Wenkai; Du, Li; Wang, Sihui; Zhou, Huijun

    2017-11-01

    The rotating saddle not only is an interesting system that is able to trap a ball near its saddle point, but can also intuitively illustrate the operating principles of quadrupole ion traps in modern physics. Unlike the conventional models based on the mass-point approximation, we study the stability of a ball in a rotating-saddle trap using rigid-body dynamics. The stabilization condition of the system is theoretically derived and subsequently verified by experiments. The results are compared with the previous mass-point model, giving large discrepancy as the curvature of the ball is comparable to that of the saddle. We also point out that the spin angular velocity of the ball is analogous to the cyclotron frequency of ions in an external magnetic field utilized in many prevailing ion-trapping schemes.

  8. Sporadic diffuse segmental interstitial cell of Cajal hyperplasia harbouring two gastric gastrointestinal stromal tumours (GIST mimicking hereditary GIST syndromes

    Directory of Open Access Journals (Sweden)

    Mafalda Costa Neves

    2015-01-01

    Conclusion: We describe a diffuse form of sporadic ICC hyperplasia harbouring multifocal GISTs, mimicking diffuse ICC hyperplasia in hereditary GIST syndromes. Detection of somatic c-KIT exon 11 mutation ruled out a hereditary disorder.

  9. Recent crustal movement and great earthquakes in Qinghai-Tibet sub-plate

    Directory of Open Access Journals (Sweden)

    Guo Liangqian

    2011-08-01

    Full Text Available Crustal movement and incremental-movement data observed repeatedly at GPS stations during 1999–2009 were analyzed to study the effect of two earthquakes of Ms8.1 and Ms8.0 that occurred in 2001 and 2008, respectively, in Qinghai-Tibet sub-plate and its eastern margin. The result revealed certain anomalous pre-earthquake deformation and some large co-seismic changes. Prior to the 2008 Wenchuan Ms8.0 earthquake, the seismogenic Kunlunshan fault zone became a geographic boundary between different regional movements. At the time of the earthquake, there was an average cross-fault crustal shortening of −1.04 m and an average right-lateral strike slip of 0.76 m along the ruptured segment, as well as a strain-energy release of −62. 66 × 10.7.

  10. The use of satellite laser observations in studying the crustal movements

    Directory of Open Access Journals (Sweden)

    Gamal F. Attia

    2012-12-01

    Full Text Available The mutual tectonic displacements of the lithospheric blocks take place within the deep fracture dividing them into hundreds and thousands kilometers long. It is possible to suggest that the reason of the accumulation of considerable local shift deformations is the change of the velocity of the tectonic motion in some or other parts of fractures as a result of different physical, chemical and mechanical processes. Nowadays, the range precision of Satellite Laser Ranging (SLR technique reaches a few millimeters level. Therefore, the space geodesy technique becomes a very important tool in detecting and monitoring recent crustal movements. Regular repeated measurements of the baselines between some stations on different plates give the possibility to construct precise and detail models of crustal movements. In this paper, the length of four baselines between Helwan-SLR station and other four SLR stations are calculated using satellite geodetical technique.

  11. A COMPARISON OF TWO METHODS FADING MEMORY FILTER AND ADAPTIVE KALMAN FILTER IN MONITORING CRUSTAL MOVEMENT

    Directory of Open Access Journals (Sweden)

    Cahit Tağı ÇELİK

    2004-01-01

    Full Text Available Monitoring the Crustal Movement in Geodesy is performed by the deformation survey and analysis. If monitoring the crustal movements involves more than two epochs of survey campaign then from the plate tectonic theory, stations do not move randomly from one epoch to the other, therefore Kalman Filter may be suitable to use. However, if sudden movements happened in the crust in particular earthquake happened, the crust moves very fast in a very short period of time. When Kalman Filter used for monitoring these movements, from associated epoch, for a number of epochs the results may be biased. In the paper, comparison of two methods for elimination of the above mentioned biases have been performed. These methods are Fading Memory Filter and Adaptive Kalman Filter for an unknown bias.

  12. Geomorphology of the Martian Crustal Dichotomy Boundary: Implications for Age and Origin

    Science.gov (United States)

    Irwin, R. P.; Watters, T. R.

    2005-12-01

    The fairly abrupt decline in surface age, elevation, and crustal thickness from the southern highlands to the northern lowlands of Mars is termed the crustal dichotomy. The cause of northern crustal thinning remains among the major unresolved issues in Mars research. Most geophysical models have invoked degree-1 mantle convection, whereas others suggest plate tectonism or one or more giant impacts in the northern hemisphere. Other studies have focused on modifications to the highland/lowland dichotomy boundary, which may or may not be relevant to the issue of origin. These hypotheses include erosion, extensional faulting, lateral crustal flow, and flexure of an elastic lithosphere by loading of the lowlands. The geomorphology of the highland/lowland boundary region provides important controls for these geophysical models of early crustal development. Geologic observations suggest that the thin lowland crust and dichotomy boundary originated in the Early Noachian Epoch (>4 Ga). The slope within ancient cratered terrain along the boundary influenced post-Noachian fresh crater morphology, Late Noachian valley network planform, and the degradation of Middle to Late Noachian (~3.95-3.7 Ga) impact craters. For fresh (post-Noachian) craters emplaced on the dichotomy slope, the plane of the rim crest inclines subparallel to the exterior slope, although the interior cavity and central peak are oriented vertically, consistent with impacts on a precursor slope. Valleys converge down modern slopes, so the cratered dichotomy slope predates Late Noachian valley development. Degraded craters within the north-sloping cratered and dissected units have floors that are flat or slightly concave, so tilting did not occur after the crater floors were emplaced in Middle Noachian to Early Hesperian time. Most crater floors along the dichotomy boundary are not dissected, as one would expect from an erosional response to Late Noachian tilting, and the few craters with dissected floors have

  13. Espisodic detachment of Martian crustal magnetic fields leading to bulk atmospheric plasma escape

    Energy Technology Data Exchange (ETDEWEB)

    Brain, D A; Baker, A H; Briggs, J; Eastwood, J P; Halekas, J S; Phan, T

    2009-06-02

    We present an analysis of magnetic field and suprathermal electron measurements from the Mars Global Surveyor (MGS) spacecraft that reveals isolated magnetic structures filled with Martian atmospheric plasma located downstream from strong crustal magnetic fields with respect to the flowing solar wind. The structures are characterized by magnetic field enhancements and rotations characteristic of magnetic flux ropes, and characteristic ionospheric electron energy distributions with angular distributions distinct from surrounding regions. These observations indicate that significant amounts of atmosphere are intermittently being carried away from Mars by a bulk removal process: the top portions of crustal field loops are stretched through interaction with the solar wind and detach via magnetic reconnection. This process occurs frequently and may account for as much as 10% of the total present-day ion escape from Mars.

  14. A recurrence of pancreatic non-functioning neuroendocrine tumor mimicking splenosis.

    Science.gov (United States)

    Kim, Yeon Ji; Paik, Chang Nyol

    2016-12-01

    There have been a number of case reports where intra-abdominal splenosis or accessory spleens have mimicked metastatic cancer. However, to the best of our knowledge, this to be the first report of a Tc-99m phytate scintigraphy study in English literature showed the uptake in the metastatic mass of pancreatic NET which had been resected for 19 years ago. Although a nuclear scintigraphy is useful method to differentiate between abdominal splenosis and metastatic cancer, the histopathological confirmation should be considered.

  15. In vitro and in vivo evaluation of the marine sponge skeleton as a bone mimicking biomaterial

    Digital Repository Service at National Institute of Oceanography (India)

    Nandi S.K.; Kundu, B.; Mahato, A.; Thakur, N.L.; Joardar, S.N.; Mandal, B.B.

    are the prerequisites in bone tissue engineering. A wide variety of scaffold matrices are currently used by researchers worldwide for effective bone healing. Selection of these materials largely depends on the tissue properties where it is to be implanted4. Ideal... characteristics of a bone scaffold material are its suitable biocompatibility, tailorable biodegradability, osteoconductive and osteoinductive nature along with structural mimicking of trabecular bone network2. Natural and synthetic scaffolds have been equally...

  16. A diet mimicking fasting promotes regeneration and reduces autoimmunity and multiple sclerosis symptoms

    OpenAIRE

    Choi, In Young; Piccio, Laura; Childress, Patra; Bollman, Bryan; Ghosh, Arko; Brandhorst, Sebastian; Suarez, Jorge; Michalsen, Andreas; Cross, Anne H.; Morgan, Todd E.; Wei, Min; Paul, Friedemann; Bock, Markus; Longo, Valter D.

    2016-01-01

    Dietary interventions have not been effective in the treatment of multiple sclerosis (MS). Here, we show that periodic 3-day cycles of a fasting mimicking diet (FMD) are effective in ameliorating demyelination and symptoms in a murine experimental autoimmune encephalomyelitis (EAE) model. The FMD reduced clinical severity in all mice and completely reversed symptoms in 20% of animals. These improvements were associated with increased corticosterone levels and regulatory T (Treg) cell numbers ...

  17. Synovial osteochondromatosis in the subacromial bursa mimicking calcific tendinitis: sonographic diagnosis.

    Science.gov (United States)

    Kim, Tae-Kwon; Lee, Dae-Hee; Park, Jong-Hoon; Kim, Chul-Hwan; Jeong, Woong-Kyo

    2014-05-01

    Synovial osteochondromatosis is an idiopathic benign metaplasia of the synovial membrane rarely found in an extra-articular bursa. We describe the case of a 55-year-old woman with synovial osteochondromatosis in the subacromial bursa mimicking calcific tendinitis. Plain radiographs showed a radiopaque mass over the middle facet of the greater tuberosity, suggesting calcific tendinitis. Sonography, however, showed a loose body in the subacromial bursa, and no evidence of calcification inside the rotator cuff. Copyright © 2013 Wiley Periodicals, Inc.

  18. Coronary artery stent mimicking intracardiac thrombus on cardiac magnetic resonance imaging due to signal loss

    DEFF Research Database (Denmark)

    Qayyum, Abbas Ali; Vejlstrup, Niels Grove; Ahtarovski, Kiril Aleksov

    2012-01-01

    Since the introduction of percutaneous coronary intervention for coronary artery disease, thousands of patients have been treated with the implantation of coronary stents. Moreover, several of the patients with coronary stent undergo cardiac magnetic resonance (CMR) imaging every year. This case ...... the signal loss on MRI associated with implanted metallic devices is known, we report a case where an implanted coronary stent in the left circumflex artery led to an intracardiac signal loss mimicking intracardiac thrombus/tumor....

  19. Homodimeric BODIPY Rotor as a Fluorescent Viscosity Sensor for Membrane-Mimicking and Cellular Environments

    Science.gov (United States)

    Raut, Sangram; Kimball, Joseph; Fudala, Rafal; Doan, Hung; Maliwal, Badri; Sabnis, Nirupama; Lacko, Andras; Gryczynski, Ignacy; Dzyuba, Sergei V.

    2015-01-01

    Fluorescence properties of a novel homodimeric BODIPY dye rotor for Fluorescence Lifetime Imaging Microscopy (FLIM) are reported. Steady state and time resolved fluorescence measurements established the viscosity dependant behaviour in vitro. Homodimeric BODIPY embedded in different membrane mimicking lipid vesicles (DPPC, POPC and POPC plus cholesterol) demonstrated to be a viable sensor for fluorescence lifetime based viscosity measurements. Moreover, SKOV3 cells readily endocytosed the dye, which accumulated in membranous structures inside cytoplasm thereby allowing viscosity mapping of internal cell components. PMID:25381865

  20. Abdominal tuberculosis with periportal lymph node involvement mimicking pancreatic malignancy in an immunocompetent adolescent.

    Science.gov (United States)

    Lee, Yeoun Joo; Hwang, Jae-Yeon; Park, Su-Eun; Kim, Yong-Woo; Lee, Jun Woo

    2014-11-01

    Abdominal tuberculosis manifesting as isolated lymphadenopathy is rare, particularly in children. Tuberculous involvement of the pancreatic head and peripancreatic area can simulate a neoplasm of the pancreatic head. To our knowledge, obstructive jaundice caused by tuberculous lymphadenopathy has not been reported in children or adolescents. Here we present radiologic findings in a case of tuberculous lymphadenopathy that mimicked malignancy of the pancreatic head and caused obstructive jaundice in an immunocompetent adolescent.

  1. Abdominal tuberculosis with periportal lymph node involvement mimicking pancreatic malignancy in an immunocompetent adolescent

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yeoun Joo; Park, Su-Eun [Pusan National University, Department of Pediatrics, Pusan National University Children' s Hospital, School of Medicine, Yangsan (Korea, Republic of); Hwang, Jae-Yeon; Kim, Yong-Woo; Lee, Jun Woo [Pusan National University, Department of Radiology, Pusan National University Yangsan Hospital, School of Medicine, Yangsan (Korea, Republic of)

    2014-11-15

    Abdominal tuberculosis manifesting as isolated lymphadenopathy is rare, particularly in children. Tuberculous involvement of the pancreatic head and peripancreatic area can simulate a neoplasm of the pancreatic head. To our knowledge, obstructive jaundice caused by tuberculous lymphadenopathy has not been reported in children or adolescents. Here we present radiologic findings in a case of tuberculous lymphadenopathy that mimicked malignancy of the pancreatic head and caused obstructive jaundice in an immunocompetent adolescent. (orig.)

  2. A Retroperitoneal Isolated Enteric Duplication Cyst Mimicking a Teratoma: A Case Report and Literature Review

    Directory of Open Access Journals (Sweden)

    Daichi Momosaka

    2016-01-01

    Full Text Available Enteric duplication cysts lacking anatomic association with the gastrointestinal tract are called isolated enteric duplication cysts (IEDCs. We present an atypical case of a retroperitoneal IEDC with a tortuous tubular complex shape that enfolded the surrounding retroperitoneal fat and mimicked a retroperitoneal teratoma. Multiplanar reconstruction images should be used to evaluate such a lesion correctly. A tortuous tubular complex shape could be a key finding to differentiate from other retroperitoneal cysts.

  3. Chemoprevention of Breast Cancer by Mimicking the Protective Effect of Early First Birth. Addendum

    Science.gov (United States)

    2013-03-01

    densities and breast cancer risk. Cancer Epidemiol Biomarkers Prev 1998;7:1133-44. 4. Bartow SA, Pathak DR, Mettler FA. Radiographic microcalcification ...AD_________________ Award Number: W81XWH-05-1-0390 TITLE: Chemoprevention of breast cancer by...REPORT TYPE Final addendum 3. DATES COVERED 2 May 2012 – 2 February 2013 4. TITLE AND SUBTITLE Chemoprevention of breast cancer by mimicking the

  4. A rare case of unilateral discoid lupus erythematosus mimicking lupus vulgaris.

    Science.gov (United States)

    Verma, Parul; Pathania, Sucheta; Kubba, Asha

    2017-11-08

    Discoidlupus erythematosus (DLE) is a chronic type of cutaneous lupus erythematosus which can present in various morphologies, and the diagnosis can be rather confounding. Prompt evaluation and treatment is necessary to prevent disfigurement and systemic involvement associated with DLE. The following case presented a diagnostic dilemma as the lesion mimicked lupus vulgaris. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  5. Ewing's sarcoma mimicking a meningioma in radiological findings: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hee Jin; Choi, Sun Seob [College of Medicine, Dong-A University, Busan (Korea, Republic of)

    2007-10-15

    Ewing's sarcoma is an uncommon primary bone tumor. Primary Ewing's sarcoma of the cranium is extremely rare and constitutes only 1% of all Ewing's sarcoma cases. Usually, primary Ewing's sarcoma of the carnium manifests as an expansile osteolytic malignant bone tumor with or without intracranial extension. We report here the radiological findings of a case of Ewing's sarcoma mimicking a meningioma in an 18-year-old man.

  6. Calea zacatechichi dichloromethane extract exhibits antidiarrheal and antinociceptive effects in mouse models mimicking irritable bowel syndrome

    OpenAIRE

    Sałaga, M.; Kowalczuk, A.; Zielinska, M.; Błażewicz, A.; Fichna, J.

    2015-01-01

    Calea zacatechichi Schltdl. (Asteraceae alt. Compositae) is a Mexican plant commonly used in folk medicine to treat respiratory and gastrointestinal (GI) disorders. The objective of this study is to characterize the effect of C. zacatechichi extracts in mouse models mimicking the symptoms of irritable bowel syndrome (IBS). Powdered C. zacatechichi herb (leaves, stems, and flowers) was extracted with methanol. Methanolic extract was filtered and evaporated giving methanolic fraction. The resid...

  7. Crustal architecture beneath the Tibet-Ordos transition zone, NE Tibet, and the implications for plateau expansion

    Science.gov (United States)

    Guo, Xiaoyu; Gao, Rui; Wang, Haiyan; Li, Wenhui; Keller, G. R.; Xu, Xiao; Li, Hongqiang; Encarnacion, John

    2015-12-01

    Most previous studies of the Tibetan Plateau have focused on the processes of crustal thickening and subsequent outward growth. However, lithospheric structure across the tectonic boundaries of the plateau has not yet been fully imaged, and therefore, how geological structures evolved in association with the lateral expansion of the margins remains unclear. Here together with interpretation of regional aeromagnetic anomalies, we employ a recently acquired 165 km long deep seismic reflection image that crosses the northeastern flank of the Tibetan Plateau. The resulting crustal "architecture" suggests that crustal shortening is a primary driver for plateau uplift of northeastern Tibet and that the Xiaoguan Shan to the east of the Liupan Shan belt marks the easternmost edge of the strata that has been affected by the northeastward growth of the plateau. In addition, decoupled crustal deformation owing to differential structural integrity has been accommodated during the subsequent northeastward growth of the plateau.

  8. Pulsating continents on Venus: An explanation for crustal plateaus and tessera terrains

    OpenAIRE

    Romeo Briones, Ignacio; Turcotte, Donald L.

    2008-01-01

    We propose that tessera terrains on Venus represent continental crust that does not participate in the periodic recycling of the lithosphere through global subduction events.We have studied the force balance on the boundary of a continental area that survives a global subduction event using an analytical model. In the proposed model, the ratio between the crustal and lithospheric mantle thicknesses controls the force balance. If the crust thickness is less than ∼2/5 of the lithosp...

  9. Crustal structure of the Agulhas Ridge (South Atlantic Ocean): Formation above a hotspot?

    Science.gov (United States)

    Jokat, Wilfried; Hagen, Claudia

    2017-10-01

    The southern South Atlantic Ocean contains several features believed to document the traces of hotspot volcanism during the early formation of the ocean basin, namely the Agulhas Ridge and the Cape Rise seamounts located in the southeast Atlantic between 36°S and 50°S. The Agulhas Ridge parallels the Agulhas-Falkland Fracture Zone, one of the major transform zones of the world. The morphology of the ridge changes dramatically from two parallel segments in the southwest, to the broad plateau-like Agulhas Ridge in the northeast. Because the crustal fabric of the ridge is unknown relating its evolution to hotspots in the southeast Atlantic is an open question. During the RV Polarstern cruise ANT-XXIII-5 seismic reflection and refraction data were collected along a 370 km long profile with 8 Ocean Bottom Stations to investigate its crustal fabric. The profile extends in NNE direction from the Agulhas Basin, 60 km south of the Agulhas Ridge, and continues into the Cape Basin crossing the southernmost of the Cape Rise seamounts. In the Cape Basin we found a crustal thickness of 5.5-7.5 km, and a velocity distribution typical for oceanic crust. The Cape Rise seamounts, however, show a higher velocity in comparison to the surrounding oceanic crust and the Agulhas Ridge. Underplated material is evident below the southernmost of the Cape Rise seamounts. It also has a 5-8% higher density compared to the Agulhas Plateau. The seismic velocities of the Agulhas Ridge are lower, the crustal thickness is approximately 14 km, and age dating of dredge samples from its top provides clear evidence of rejuvenated volcanism at around 26 Ma. Seismic data indicate that although the Cape Rise seamounts formed above a mantle thermal anomaly it had a limited areal extent, whereas the hotspot material that formed the Agulhas Ridge likely erupted along a fracture zone.

  10. Stochastic Stick - Slip Model Linking Crustal Shear Strength and Earthquake Interevent Times

    OpenAIRE

    Dionissios T. Hristopulos; V. Mouslopoulou

    2012-01-01

    The current understanding of the earthquake interevent times distribution (ITD) is incomplete. The Weibull distribution is often used to model the earthquake ITD. We link the earthquake ITD on single faults with the Earth's crustal shear strength distribution by means of a phenomenological stick - slip model. We obtain Weibull ITD for power-law stress accumulation, i.e., $\\sigma(t) = \\alpha t^{\\beta}$, where $\\beta >0$ for single faults or systems with homogeneous strength statistics. We show...

  11. Shallow and deep crustal control on differentiation of calc-alkaline and tholeiitic magma

    Science.gov (United States)

    Hora, John M.; Singer, Brad S.; Wörner, Gerhard; Beard, Brian L.; Jicha, Brian R.; Johnson, Clark M.

    2009-07-01

    The role of changing crustal interaction and plumbing geometry in modulating calc-alkaline vs. tholeiitic magma affinity is well illustrated by the influence of 70 km thick crust beneath Volcán Parinacota. Changes in petrologic affinity correlate with periods of cone-building, sector collapse, and rebuilding of the volcano over the last 52 ka, and are well explained by changes in magma recharge regime. With increasing recharge and magma output, lavas transition from low-Fe, strongly calc-alkaline, phenocryst-rich silicic compositions to medium-Fe, near-tholeiitic, mafic, and aphanitic characteristics. Strontium isotope data show that the change in magma regime did not affect all parts of the system simultaneously; these are characterized by distinctive 87Sr/ 86Sr ratios, which suggest an initially compartmentalized system. Relatively high ( 230Th/ 232Th) activity ratios of ~ 0.72 in early-erupted calc-alkaline lavas are consistent with interaction with high-U upper crust. Low ( 230Th/ 232Th) activity ratios of ~ 0.55 and up to 33% Th-excess in younger near-tholeiitic lavas correlate with steep REE patterns, indicating lower-crustal interaction. Thorium-excesses at the time of eruption approach the maximum that can be generated via small-degree garnet-residual melting in the lower crust or mantle and imply that transit time through the crustal column for the most tholeiitic magmas had to be short, on the order of secular equilibrium, suggesting stagnation times > 3 × 10 5 yr in the upper crust. In addition to more traditional explanations tied to magma source, expression of low-Fe 'calc-alkaline' (CA) vs. medium-Fe 'near-tholeiitic' (TH) magma series at the scale of individual volcanoes is likely to be modulated by transitions from compartmentalized, stagnant, assimilation-prone 'dirty' systems (CA) to 'clean' systems (TH) that are characterized by rapid magma throughput and minimal opportunity for upper-crustal contamination.

  12. The Crustal and Mantle Velocity Structure in Central Asia from 3D Travel Time Tomography

    Science.gov (United States)

    2010-09-01

    that the deformation in the shallow brittle crust occurs on a distributed network of faults, and some regions, such as the Tarim Basin , the Ordos and...Kunlun and the Tarim Basin (Molnar and Tapponnier, 1978). The Main Pamir Thrust has been interpreted to have accommodated about 300 km of crustal...southern Pamir, Kazakh shield, and the Tarim basin . High velocities delineate the subduction zones and active or fossil slabs. The Moho depth in the

  13. Crustal velocity structure of the Deccan Volcanic Province, Indian Peninsula, from observed surface wave dispersion

    Directory of Open Access Journals (Sweden)

    Gaddale Suresh

    2014-08-01

    Full Text Available Through inversion of fundamental mode group velocities of Love and Rayleigh waves, we study the crustal and subcrustal structure across the central Deccan Volcanic Province (DVP, which is one of the world’s largest terrestrial flood basalts. Our analysis is based on broadband seismograms recorded at seismological station Bhopal (BHPL in the central India from earthquakes located near west coast of India, with an average epicentral distance about 768 km. The recording station and epicentral zone are situated respectively on the northern and southern edges of DVP with wave paths across central DVP. The period of group velocity data ranges from 5 to 60 s for Rayleigh waves and 5 to 45 s for Love waves. Using the genetic algorithm, the observed data have been inverted to obtain the crust and subcrustal velocity structure along the wavepaths. Using this procedure, a similar velocity structure was also obtained earlier for the northwestern DVP, which is in the west of the present study region. Comparison of results show that the crustal thickness decreases westward from central DVP (39.6 km to northwestern DVP (37.8 km along with the decrease of thickness of upper crust; while the thickness of lower crust remains nearly same. From east to west S-wave velocity in the upper crust decreases by 2 to 3 per cent, while P-wave velocity in the whole crust and subcrust decreases by 3 to 6 per cent. The P- and S-wave velocities are positively correlated with crustal thickness and negatively correlated with earth’s heat flow. It appears that the elevated crustal and subcrustal temperature in the western side is the main factor for low velocities on this side.

  14. The diverse crustal structure and magmatic evolution of the Manihiki Plateau, central Pacific

    Science.gov (United States)

    Hochmuth, K.; Gohl, K.; Uenzelmann-Neben, G.; Werner, R.

    2014-07-01

    The Manihiki Plateau is a Large Igneous Province (LIP) in the central Pacific. It was emplaced as part of the "Super-LIP" Ontong Java Nui and experienced fragmentation into three sub-plateaus, possibly during the break-up of Ontong Java Nui. The Manihiki Plateau is presumably the centerpiece of this "Super-LIP" and its investigation can therefore decipher the break-up mechanisms as well as the evolution of the plateau after its initial emplacement. By analyzing two seismic refraction/wide-angle reflection profiles crossing the two largest sub-plateaus of the Manihiki Plateau, the High Plateau and the Western Plateaus, we give new insights into their crustal structure and magmatic evolution. The High Plateau shows a crustal structure of 20 km thickness and a seismic P wave velocity distribution, which is comparable to other LIPs. The High Plateau experienced a strong secondary volcanism, which can be seen in relicts of seamount chain volcanism. The Western Plateaus on the other hand show no extensive secondary volcanism and are mainly structured by fault systems and sedimentary basins. A constant decrease in Moho depth (9-17 km) is a further indicator of crustal stretching on the Western Plateaus. Those findings lead to the conclusion, that the two sub-plateaus of the Manihiki Plateau experienced a different magmatic and tectonic history. Whereas the High Plateau experienced a secondary volcanism, the Western Plateaus underwent crustal stretching during and after the break-up of Ontong Java Nui. This indicates, that the sub-plateaus of the Manihiki Plateau play an individual part in the break-up history of Ontong Java Nui.

  15. Influence of crustal fluids on growth and activity of marine deep biosphere microbial populations

    OpenAIRE

    Fichtel, Katja

    2014-01-01

    Like seawater, hydrothermal crustal fluids might support abundance, diversity and activity of microorganisms in marine sediments. The present work shows high numbers of metabolically active microorganisms in deep sediments overlying a midoceanic ridge. Sulfate diffusion from the bedrock fuels microbial sulfate reduction and anaerobic oxidation of methane. From crust-near layers non-sporeforming, sulfate-reducing Deltaproteobacteria were isolated, able to grow chemoheterotrophically, ferme...

  16. High resolution regional crustal models from irregularly distributed data: Application to Asia and adjacent areas

    OpenAIRE

    Stolk, W; Mikhail Kaban; F. Beekman; Magdala Tesauro; Mooney, W.D.; Cloetingh, S.

    2013-01-01

    We propose a new methodology to obtain crustal models in areas where data is sparse and data spreading is heterogeneous. This new method involves both interpolating the depth to the Moho discontinuity between observations and estimating a velocity–depth curve for the crust at each interpolation location. The Moho observations are interpolated using a remove–compute–restore technique, used in for instance geodesy. Observations are corrected first for Airy type isostasy. The residual observatio...

  17. A crustal model for a northeast-southwest profile through Ireland

    Science.gov (United States)

    Jacob, A. W. B.; Kaminski, W.; Murphy, T.; Phillips, W. E. A.; Prodehl, C.

    1985-03-01

    The Irish Caledonian Suture Seismic Project (ICSSP) consisting of a 250 km seismic refraction line was carried out in conjunction with, and as an extension of, the Caledonian Suture Seismic Project (CSSP) of the University of Durham. 51 seismic recording sites at 5 km intervals were deployed on the northwest flank of the Suture Zone in Ireland. Recordings were made from three shot points at the southwest of the line and from 31 shot points of the Durham programme in the North Irish Sea. A crustal model is presented which is based exclusively on a travel-time interpretation. The Pg velocities recorded in eastern Ireland rise quite rapidly with depth to 6.3-6.5 km/s but in the western part of the profile lower velocities between 6.0 and 6.3 km/s were recorded. Prominent energy in later arrivals can be correlated by two reflected phases from a mid-crustal boundary and the Moho. A low-velocity zone is present at the northeastern end of the line and a mid-crustal layer with an average velocity of about 6.4 km/s is separated from the lower crust, mean velocity 6.8 km/s, by a well established mid-crustal boundary zone of 1-2 km thickness at about 20 km depth. The Moho, around 32 km at its deepest, shallows towards the sea at both ends of the line. It is a sharp discontinuity under western Ireland but a transition zone of 3-4 km thickness in the east. An interpretation is given which takes into account (a) the geologic and tectonic history of Ireland and (b) data derived from the gravity and magnetic fields.

  18. Crustal modeling of the central part of the Northern Western Desert, Egypt using gravity data

    Science.gov (United States)

    Alrefaee, H. A.

    2017-05-01

    The Bouguer anomaly map of the central part of the Northern Western Desert, Egypt was used to construct six 2D gravity models to investigate the nature, physical properties and structures of the crust and upper mantle. The crustal models were constrained and constructed by integrating results from different geophysical techniques and available geological information. The depth to the basement surface, from eight wells existed across the study area, and the depth to the Conrad and Moho interfaces as well as physical properties of sediments, basement, crust and upper mantle from previous petrophysical and crustal studies were used to establish the gravity models. Euler deconvolution technique was carried on the Bouguer anomaly map to detect the subsurface fault trends. Edge detection techniques were calculated to outlines the boundaries of subsurface structural features. Basement structural map was interpreted to reveal the subsurface structural setting of the area. The crustal models reveals increasing of gravity field from the south to the north due to northward thinning of the crust. The models reveals also deformed and rugged basement surface with northward depth increasing from 1.6 km to 6 km. In contrast to the basement, the Conrad and Moho interfaces are nearly flat and get shallower northward where the depth to the Conrad or the thickness of the upper crust ranges from 18 km to 21 km while the depth to the Moho (crustal thickness) ranges from 31.5 km to 34 km. The crust beneath the study area is normal continental crust with obvious thinning toward the continental margin at the Mediterranean coast.

  19. Crustal architecture and geodynamics of North Queensland, Australia: Insights from deep seismic reflection profiling

    Science.gov (United States)

    Korsch, R. J.; Huston, D. L.; Henderson, R. A.; Blewett, R. S.; Withnall, I. W.; Fergusson, C. L.; Collins, W. J.; Saygin, E.; Kositcin, N.; Meixner, A. J.; Chopping, R.; Henson, P. A.; Champion, D. C.; Hutton, L. J.; Wormald, R.; Holzschuh, J.; Costelloe, R. D.

    2012-10-01

    A deep crustal seismic reflection and magnetotelluric survey, conducted in 2007, established the architecture and geodynamic framework of north Queensland, Australia. Results based on the interpretation of the deep seismic data include the discovery of a major, west-dipping, Paleoproterozoic (or older) crustal boundary, considered to be an ancient suture zone, separating relatively nonreflective, thick crust of the Mount Isa Province from thinner, two layered crust to the east. Farther to the east, a second major crustal boundary also dips west or southwest, offsetting the Moho and extending below it, and is interpreted as a fossil subduction zone. Across the region, the lower crust is mostly highly reflective and is subdivided into three mappable seismic provinces, but they have not been tracked to the surface. In the east, the Greenvale and Charters Towers Provinces, part of the Thomson Orogen, have been mapped on the surface as two discrete provinces, but the seismic interpretation raises the possibility that these two provinces are continuous in the subsurface, and also extend northwards to beneath the Hodgkinson Province, originally forming part of an extensive Neoproterozoic-Cambrian passive margin. Continuation of the Thomson Orogen at depth beneath the Hodgkinson and Broken River Provinces suggests that these provinces (which formed in an oceanic environment, possibly as an accretionary wedge at a convergent margin) have been thrust westwards onto the older continental passive margin. The Tasman Line, originally defined to represent the eastern limit of Precambrian rocks in Australia, has a complicated geometry in three dimensions, which is related to regional deformational events during the Paleozoic. Overall, the seismic data show evidence for a continental margin with a long history (Paleoproterozoic to early Mesozoic) but showing only limited outward growth by crustal accretion, because of a repeated history of overthrust shortening during repeated

  20. Regional Crustal Components of Martian Heat Flow from Mars Odyssey Gamma-Ray Spectrometry (GRS)

    Science.gov (United States)

    Hahn, B. C.; McLennan, S. M.

    2009-12-01

    Martian thermal state and evolution depend principally on the heat-producing element distributions in the planet’s crust and mantle, specifically the incompatible radiogenic isotopes of K, Th, and U. Normally these elements are preferentially sequestered into a planet’s crust during differentiation, and this is especially true for Mars, which possesses a thick and mostly ancient crust that is proportionally large with respect to the planet’s total volume. The Gamma-Ray Spectrometer (GRS) instrument on board the 2001 Mars Odyssey spacecraft can detect all three of these elements and has been used to map the K and Th abundances across nearly the entire Martian surface. It has been estimated that as much as 50% or more of the Martian planetary budget of heat producing elements has seen sequestered into the crust during planetary differentiation due to their incompatibility in igneous processes; a process that mostly took place very early in Martian geological history. As such, the crustal component of heat flow represents as much as half of the total planetary output of radiogenic heat. While GRS measurements can not constrain heat flow from mantle sources, previous work calculated the average crustal component of heat flow of 6.43 mW/m2 based on radiogenic elemental abundances. Orbital GRS data are of lower spatial resolution (5°x5° per pixel) than most other orbital remote sensing instruments and, accordingly, are best suited for global or large, regional-scale studies, rather than detailed, local analyses of geographically small features and landforms. Here we present detailed calculations for specific, areally-large, regions and geologic provinces on Mars, reporting the present-day crustal component of heat flow, the crustal heat flow at time of regional formation, and constraints of geothermal gradients from these measurements.

  1. Crustal structure of the SW Iberian passive margin: The westernmost remnant of the Ligurian Tethys?

    Science.gov (United States)

    Ramos, A.; Fernández, O.; Torne, M.; Sánchez de la Muela, A.; Muñoz, J. A.; Terrinha, P.; Manatschal, G.; Salas, M. C.

    2017-05-01

    At present, the SW Iberian margin is located along the convergent Iberia-Nubia plate boundary. In Mesozoic times, the margin was located at the triple junction of the Ligurian Tethys, Central Atlantic and Northern Atlantic. The characterization of its crustal structure has allowed us to propose a configuration for this triple junction and to determine the role that this transform margin played within the plate kinematic system. In this paper we present an integrated study based on the interpretation of a 2D regional multichannel seismic survey consisting of 58 profiles, tied with onshore geology and exploratory wells, and on gravimetric modeling performed over four NW-SE trending profiles. Integrated interpretation of MCS data combined with 2D gravity modeling reveals a complex pattern in the southward crustal thinning of SW Iberia and supports the possible presence of oceanic crust under the Gulf of Cadiz. The tapering of Iberian crust is characterized by steps with rapid changes in the thickness of the crust, and thinning to Based on gravimetric modeling results and the structures interpreted on reflection seismic profiles, 3 crustal domains reflecting progressive thinning have been defined for the SW Iberian margin. These domains trend roughly WSW-ENE, parallel to the main extensional fabric of the margin. Gravimetric modeling results are compatible with the presence of exhumed sub-continental mantle in the distal part of the margin. Integrated modeling also supports the fact that Cenozoic contraction is responsible for major uplift along the Guadalquivir Bank. Margin inversion and the pre-existing extensional crustal structure are responsible for the areal distribution and amplitude of the prominent positive gravity anomaly observed in the Gulf of Cadiz.

  2. Colon cancer metastasis mimicking intraductal papillary neoplasm of the extra-hepatic bile duct.

    Science.gov (United States)

    Yamao, Takanobu; Hayashi, Hiromitsu; Higashi, Takaaki; Takeyama, Hideyuki; Kaida, Takayoshi; Nitta, Hidetoshi; Hashimoto, Daisuke; Chikamoto, Akira; Beppu, Toru; Baba, Hideo

    2015-01-01

    An accurate diagnosis of the primary cancer in cases with metastatic lesions is quite important because misdiagnosis may lead to the selection of incorrect adjuvant therapy and worse long-term outcomes after surgery. The metastatic sites associated with the dissemination of colon cancer are well known and normally predictable, which includes the lymphatic, haematogenous, or peritoneal regions, while other locations are quite rare. In this report, we present a case of colon cancer with an unusual metastatic pattern mimicking an intraductal papillary neoplasm of the bile duct (IPNB) present in the extra-hepatic bile duct with a cytokeratin (CK)-7-negative and CK-20-positive profile (intestinal type). In the case of this patient who had a history of colon cancer, immunohistochemical staining for the CKs was useful for distinguishing between primary IPNB and colon cancer metastases. We suspect that the metastatic pattern of this case of colon cancer that mimicked IPNB at the extra-hepatic bile duct developed incidentally via the bile stream. This is a rare case of colon cancer metastasis mimicking IPNB at the extra-hepatic bile duct. Our findings also suggest that there may be an incidental 4th metastatic route via the bile stream. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Interaction of fengycin with stratum corneum mimicking model membranes: a calorimetry study.

    Science.gov (United States)

    Eeman, Marc; Olofsson, Gerd; Sparr, Emma; Nasir, Mehmet Nail; Nylander, Tommy; Deleu, Magali

    2014-09-01

    Based on its outstanding antifungal properties, it is reasonable to believe that fengycin might be efficient to topically treat localized dermatomycoses. Since most of the fungi species involved in the formation of those mycotic skin diseases colonize primarily the stratum corneum (SC), studying the interaction between fengycin and SC-mimicking lipid membranes is a primary step to determine the potential of fengycin to overcome the physical barrier of the skin. In this respect, multilamellar lipid vesicles (MLVs), with a lipid composition mimicking that of the SC, were prepared and characterized by differential scanning calorimetry (DSC). The critical micelle concentration (CMC) of fengycin was also assessed under skin conditions and found to be 1.2±0.1μM. The molecular interactions of fengycin with SC-mimicking MLVs were investigated by both DSC and isothermal titration calorimetry (ITC). Results showed that the interactions were considerably affected by changes in lipid phase behaviour. At 40°C and below, fengycin induced exothermic changes in the lipid structures suggesting that less-ordered lipid domains became more-ordered in presence of fengycin. At 60°C, clearly endothermic interaction enthalpies were observed, which could arise from the "melting" of remaining solid domains enriched in high melting lipids that without fengycin melt at higher temperatures. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Antimicrobial Peptide Mimicking Primary Amine and Guanidine Containing Methacrylamide Copolymers Prepared by Raft Polymerization

    Science.gov (United States)

    Exley, Sarah E.; Paslay, Lea C.; Sahukhal, Gyan S.; Abel, Brooks A.; Brown, Tyler D.; McCormick, Charles L.; Heinhorst, Sabine; Koul, Veena; Choudhary, Veena; Elasri, Mohamed O.; Morgan, Sarah E.

    2016-01-01

    Naturally occurring antimicrobial peptides (AMPs) display the ability to eliminate a wide variety of bacteria, without toxicity to the host eukaryotic cells. Synthetic polymers containing moieties mimicking lysine and arginine components found in AMPs have been reported to show effectiveness against specific bacteria, with the mechanism of activity purported to depend on the nature of the amino acid mimic. In an attempt to incorporate the antimicrobial activity of both amino acids into a single water-soluble copolymer, a series of copolymers containing lysine mimicking aminopropyl methacrylamide (APMA) and arginine mimicking guanadinopropyl methacrylamide (GPMA) were prepared via aqueous RAFT polymerization. Copolymers were prepared with varying ratios of the comonomers, with degree of polymerization of 35–40 and narrow molecular weight distribution to simulate naturally occurring AMPs. Antimicrobial activity was determined against Gram-negative and Gram-positive bacteria under conditions with varying salt concentration. Toxicity to mammalian cells was assessed by hemolysis of red blood cells and MTT assays of MCF-7 cells. Antimicrobial activity was observed for APMA homopolymer and copolymers with low concentrations of GPMA against all bacteria tested, with low toxicity toward mammalian cells. PMID:26558609

  5. A modified least-squares collocation method for the determination of crustal deformation: first results in the Swiss Alps

    OpenAIRE

    Egli, R.; Geiger, A.; Wiget, A.; Kahle, H.-G

    2017-01-01

    The calculation of recent crustal movements and the associated crustal deformation rely on a suitable interpolation of geodetic measurements with repetition cycles of years or decades and modern GPS permanent networks. A common interpolation methods is the least-square collocation (LSC). LSC requires some a priori assumptions about the characteristics of the velocity field, that is, stocasticity in Moritz's definition of LSC. We present a novel approach, called adaptative LSC (ALSC) to the in...

  6. Three-dimensional crustal deformations and strain field features constrained by dense GPS measurements in Northeastern Tibet

    Science.gov (United States)

    Zhang, Tengxu; Shen, Wen-Bin; Pan, Yuanjin

    2017-04-01

    The ongoing collision between the India plate and Eurasia plate brings N-S crustal shortening and thickening of the Tibetan Plateau. Here, using measurements from 40 Continuous Global Positioning System (CGPS) stations of the Crustal Movement Observation Network of China (CMONOC) we determine the latest three-dimensional crustal deformations in the NET region, and based on the Principal component analysis (PCA) technique we calculate and correct the common mode errors (CME). We also use GRACE observations to determine the deformations caused by surface pressure, non-tidal oceanic mass loading and hydrological loading. We find both GPS and GRACE observations show significant seasonal variation, and the observed seasonal vertical variation exhibits a good agreement with GRACE. The annual peak-to-peak amplitudes are between 3 and 40 mm/yr. The corrected vertical crustal deformation indicate that both the crustal uplift and subsidence are anisotropic in NET, and that the maximum uplift rate in the Longmen Shan fault reach 9.5mm/yr. We further use the horizontal velocity to calculate the strain rates throughout the NET. The result indicates that the shear band maintains feature consistent with the strike-slip fault along the Longmen Shan fault and Haiyuan fault. The crustal compression and extension can describe the uplifting and sinking of the crustal in a reasonable way. This study is supported by National 973 Project China (grant No. 2013CB733302) and NSFCs (grant Nos. 41174011, 41429401, 41210006, 41128003, 41021061); Guangxi Key Laboratory of Spatial Information and Geomatics (Grant No.1103108-12); Open Fund of Guangxi Key Laboratory of Spatial Information and Geomatics (Grant Nos. 15-140-07-32 and 14-045-24-17). Keywords: Continuous GPS observation; GRACE observation; principal component analysis; common mode error; crustal vertical deformation; strain rates

  7. Distinct crustal isostasy trends east and west of the Rocky Mountain Front

    Science.gov (United States)

    Schmandt, Brandon; Lin, Fan-Chi; Karlstrom, Karl E.

    2015-12-01

    Seismic structure beneath the contiguous U.S. was imaged with multimode receiver function stacking and inversion of Rayleigh wave dispersion and ellipticity measurements. Crust thickness and elevation are weakly correlated across the contiguous U.S., but the correlation is ~3-4 times greater for separate areas east and west of the Rocky Mountain Front (RMF). Greater lower crustal shear velocities east of the RMF, particularly in low-elevation areas with thick crust, are consistent with deep crustal density as the primary cause of the contrasting crust thickness versus elevation trends. Separate eastern and western trends are best fit by Airy isostasy models that assume lower crust to uppermost mantle density increases of 0.18 g/cm3 and 0.40 g/cm3, respectively. The former value is near the minimum that is plausible for felsic lower crust. Location of the transition at the RMF suggests that Laramide to post-Laramide processes reduced western U.S. lower crustal density.

  8. Crustal thickness estimates for Baja California, Sonora, and Sinaloa, Mexico, using disperse surface waves

    Science.gov (United States)

    López-Pineda, Leobardo; Rebollar, Cecilio J.; Quintanar, Luis

    2007-04-01

    Dispersed surface waves of regional events recorded at Network of Autonomously Recording Seismographs (NARS)-Baja and Red Sísmica de Banda Ancha (RESBAN) networks located over the Baja California Peninsula, Sonora, and Sinaloa, Mexico, were used to estimate shear wave elastic models and crustal thickness. We analyzed fundamental modes of surface waves with period between 10 and 40 s. Multiple filter analysis and the inversion method described by Herrmann and Ammon (2003) was used. Crustal thickness estimates for the Peninsular Ranges of Northern Baja California agree with those obtained by previous studies in the Peninsular Ranges of Northern Baja California. We analyzed dispersion of surface waves with northwest-southeast travel paths along the east and west sides of the Baja California Peninsula as well as a northwest-southeast travel path along the western sides of the Mexican states of Sonora and Sinaloa. It was found that the crustal structure east of the Baja California Peninsula is similar to the structure of Sonora and Sinaloa. The correlation between those two structures suggests dextral offset of the order of 275 ± 25 km if we consider Baja California Peninsula as a rigid body moving toward the northwest relative to the North America plate. This displacement between the structures is in agreement with the displacement determined by the dating of Miocene deposits located in San Felipe on the Baja California Peninsula (Pacific plate), and Isle Tiburon located west of Sonora (North America plate).

  9. Crustal structure of the NW Moroccan margin from deep seismic data (SISMAR Cruise)

    Science.gov (United States)

    Jaffal, Mohammed; Klingelhoefer, Frauke; Matias, Luis; Teixeira, Fernando; Amrhar, Mostafa

    2009-06-01

    During the SISMAR cruise (spring 2001), new deep seismic data were acquired on the Atlantic Moroccan margin. The purpose of the present work is to analyse and to interpret a part of the data consisting of four wide-angle seismic profiles (4, 5, 8 and 10) recorded offshore El Jadida. Lines 4 and 5, perpendicular to the margin, show a crustal thickness of 35 km under the western Moroccan Meseta which thins progressively seaward where it reaches a minimum thickness of 10 km. The calculated velocity models show that this crust consists of two crustal layers overlain by a sedimentary cover corresponding to the post-Paleozoic sediments, characterised by a low velocity. The detailed shallow structure is obtained primarily from multichannel seismic data. Half grabens are imaged and display deeper basins located at the foot of the continental slope where the sedimentary cover reaches a maximum thickness of 6 km. The sedimentary strata are disrupted by salt migration along faults and forming diapirs. The first crustal unit corresponds to the upper crust, with p-wave velocities ranging from 6 km/s at the top to 6.5 km/s at the base. The lower crust represented by the second unit is characterized by velocities increasing from 6.7 to 7.5 km/s at the base of the lower crust.

  10. Crustal thickness and Moho sharpness beneath the Midcontinent rift from receiver functions

    Directory of Open Access Journals (Sweden)

    Moikwathai Moidaki

    2013-02-01

    Full Text Available The Mesoproterozoic Midcontinent rift (MCR in the central US is an approximately 2000 km long, 100 km wide structure from Kansas to Michigan. During the 20-40 million years of rifting, a thick (up to 20 km layer of basaltic lava was deposited in the rift valleys. Quantifying the effects of the rifting and associated volcanic eruptions on the structure and composition of the crust and mantle beneath the MCR is important for the understanding of the evolution of continental lithosphere. In this study we measure the crustal thickness (H, and the sharpness of the Moho (R at about 24 portable and permanent stations in Iowa, Kansas, and South Dakota by stacking Pto- S converted waves (PmS and their multiples (PPmS and PSmS. Under the assumption that the crustal mean velocity in the study area is the same as the IASP91 earth model, we find a significantly thickened crust beneath the MCR of about 53 km. The crustal Vp/Vs ratios increases from about 1.80 off rift to as large as 1.95 within the rift, which corresponds to an increase of Poisson’s ratio from 0.28 to 0.32, suggesting a more mafic crust beneath the MCR. The R measurements are spatially variable and are relatively small in the vicinity of the MCR, indicating the disturbance of the original sharp Moho by the rifting and magmatic intrusion and volcanic eruption.

  11. Simulations of tremor-related creep reveal a weak crustal root of the San Andreas Fault

    Science.gov (United States)

    Shelly, David R.; Bradley, Andrew M.; Johnson, Kaj M.

    2013-01-01

    Deep aseismic roots of faults play a critical role in transferring tectonic loads to shallower, brittle crustal faults that rupture in large earthquakes. Yet, until the recent discovery of deep tremor and creep, direct inference of the physical properties of lower-crustal fault roots has remained elusive. Observations of tremor near Parkfield, CA provide the first evidence for present-day localized slip on the deep extension of the San Andreas Fault and triggered transient creep events. We develop numerical simulations of fault slip to show that the spatiotemporal evolution of triggered tremor near Parkfield is consistent with triggered fault creep governed by laboratory-derived friction laws between depths of 20–35 km on the fault. Simulated creep and observed tremor northwest of Parkfield nearly ceased for 20–30 days in response to small coseismic stress changes of order 104 Pa from the 2003 M6.5 San Simeon Earthquake. Simulated afterslip and observed tremor following the 2004 M6.0 Parkfield earthquake show a coseismically induced pulse of rapid creep and tremor lasting for 1 day followed by a longer 30 day period of sustained accelerated rates due to propagation of shallow afterslip into the lower crust. These creep responses require very low effective normal stress of ~1 MPa on the deep San Andreas Fault and near-neutral-stability frictional properties expected for gabbroic lower-crustal rock.

  12. Distinct crustal isostasy trends east and west of the Rocky Mountain Front

    KAUST Repository

    Schmandt, Brandon

    2015-12-14

    © 2015. American Geophysical Union. All Rights Reserved. Seismic structure beneath the contiguous U.S. was imaged with multimode receiver function stacking and inversion of Rayleigh wave dispersion and ellipticity measurements. Crust thickness and elevation are weakly correlated across the contiguous U.S., but the correlation is ∼3-4 times greater for separate areas east and west of the Rocky Mountain Front (RMF). Greater lower crustal shear velocities east of the RMF, particularly in low-elevation areas with thick crust, are consistent with deep crustal density as the primary cause of the contrasting crust thickness versus elevation trends. Separate eastern and western trends are best fit by Airy isostasy models that assume lower crust to uppermost mantle density increases of 0.18 g/cm3 and 0.40 g/cm3, respectively. The former value is near the minimum that is plausible for felsic lower crust. Location of the transition at the RMF suggests that Laramide to post-Laramide processes reduced western U.S. lower crustal density.

  13. Osteoid osteoma and osteoid osteoma-mimicking lesions: biopsy findings, distinctive MDCT features and treatment by radiofrequency ablation

    Energy Technology Data Exchange (ETDEWEB)

    Becce, Fabio [Centre Hospitalier Universitaire Vaudois, Department of Diagnostic and Interventional Radiology, Lausanne (Switzerland); Universite Paris Descartes, Department of Radiology B, Hopital Cochin, AP-HP, Paris (France); Theumann, Nicolas [Centre Hospitalier Universitaire Vaudois, Department of Diagnostic and Interventional Radiology, Lausanne (Switzerland); Rochette, Antoine; Campagna, Raphael; Drape, Jean-Luc; Feydy, Antoine [Universite Paris Descartes, Department of Radiology B, Hopital Cochin, AP-HP, Paris (France); Larousserie, Frederique [Universite Paris Descartes, Department of Anatomic Pathology, Hopital Cochin, AP-HP, Paris (France); Cherix, Stephane; Mouhsine, Elyazid [Centre Hospitalier Universitaire Vaudois, Department of Orthopaedic and Traumatologic Surgery, Lausanne (Switzerland); Guillou, Louis [University Institute of Pathology, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Anract, Philippe [Universite Paris Descartes, Department of Orthopaedic Surgery, Hopital Cochin, AP-HP, Paris (France)

    2010-10-15

    To report the biopsy findings of osteoid osteoma (OO) and OO-mimicking lesions, assess their distinctive multidetector computed tomography (MDCT) features and evaluate treatment by radiofrequency ablation (RFA). In this multicentric retrospective study, 80 patients (54 male, 26 female, mean age 24.1 years, range 5-48) with presumed (clinical and MDCT features) OO were treated by percutaneous RFA between May 2002 and June 2009. Per-procedural biopsies were always performed. The following MDCT features were assessed: skeletal distribution and location within the bone, size, central calcification, surrounding osteosclerosis and periosteal reaction. Clinical success of RFA was evaluated. Histopathological diagnoses were: 54 inconclusive biopsies, 16 OO, 10 OO-mimicking lesions (5 chronic osteomyelitis, 3 chondroblastoma, 1 eosinophilic granuloma, 1 fibrous dysplasia). OO-mimicking lesions were significantly greater in size (p = 0.001) and presented non-significant trends towards medullary location (p = 0.246), moderate surrounding osteosclerosis (p = 0.189) and less periosteal reaction (p = 0.197), compared with OO. Primary success for ablation of OO-mimicking lesions was 100% at 1 month, 85.7% at 6 and 12 months, and 66.7% at 24 months. Secondary success was 100%. Larger size, medullary location, less surrounding osteosclerosis and periosteal reaction on MDCT may help differentiate OO-mimicking lesions from OO. OO-mimicking lesions are safely and successfully treated by RFA. (orig.)

  14. Micro-Machined Flow Sensors Mimicking Lateral Line Canal Neuromasts

    Directory of Open Access Journals (Sweden)

    Hendrik Herzog

    2015-08-01

    Full Text Available Fish sense water motions with their lateral line. The lateral line is a sensory system that contains up to several thousand mechanoreceptors, called neuromasts. Neuromasts occur freestanding on the skin and in subepidermal canals. We developed arrays of flow sensors based on lateral line canal neuromasts using a biomimetic approach. Each flow sensor was equipped with a PDMS (polydimethylsiloxane lamella integrated into a canal system by means of thick- and thin-film technology. Our artificial lateral line system can estimate bulk flow velocity from the spatio-temporal propagation of flow fluctuations. Based on the modular sensor design, we were able to detect flow rates in an industrial application of tap water flow metering. Our sensory system withstood water pressures of up to six bar. We used finite element modeling to study the fluid flow inside the canal system and how this flow depends on canal dimensions. In a second set of experiments, we separated the flow sensors from the main stream by means of a flexible membrane. Nevertheless, these biomimetic neuromasts were still able to sense flow fluctuations. Fluid separation is a prerequisite for flow measurements in medical and pharmaceutical applications.

  15. Relative Roles of Source Composition, Fractional Crystallization and Crustal Contamination in the Petrogenesis of Andean Volcanic Rocks

    Science.gov (United States)

    Thorpe, R. S.; Francis, P. W.; O'Callaghan, L.

    1984-04-01

    There are well established differences in the chemical and isotopic characteristics of the calc-alkaline basalt--andesite--decite--rhyolite association of the northern (n.v.z.), central (c.v.z.) and southern volcanic zones (s.v.z.) of the South American Andes. Volcanic rocks of the alkaline basalt--trachyte association occur within and to the east of these active volcanic zones. The chemical and isotopic characteristics of the n.v.z. basaltic andesites and andesites and the s.v.z. basalts, basaltic andesites and andesites are consistent with derivation by fractional crystallization of basaltic parent magmas formed by partial melting of the asthenospheric mantle wedge containing components from subducted oceanic lithosphere. Conversely, the alkaline lavas are derived from basaltic parent magmas formed from mantle of `within-plate' character. Recent basaltic andesites from the Cerro Galan volcanic centre to the SE of the c.v.z. are derived from mantle containing both subduction zone and within-plate components, and have experienced assimilation and fractional crystallization (a.f.c.) during uprise through the continental crust. The c.v.z. basaltic andesites are derived from mantle containing subduction-zone components, probably accompanied by a.f.c. within the continental crust. Some c.v.z. lavas and pyroclastic rocks show petrological and geochemical evidence for magma mixing. The petrogenesis of the c.v.z. lavas is therefore a complex process in which magmas derived from heterogeneous mantle experience assimilation, fractional crystallization, and magma mixing during uprise through the continental crust. Active Andean volcanoes of the calc-alkaline basalt--andesite--dacite rhyolite association occur within a northern (n.v.z.), central (c.v.z.) and southern volcanic zone (s.v.z.) (figure 9). Alkaline volcanic rocks occur within and to the east of these zones. The n.v.z. and s.v.z. lavas have chemical and isotope characteristics consistent with an origin by

  16. Influences of crustal thickening in the Tibetan Plateau on loading modeling and inversion associated with water storage variation

    Directory of Open Access Journals (Sweden)

    Hansheng Wang

    2015-05-01

    Full Text Available We use the average crustal structure of the CRUST1.0 model for the Tibetan Plateau to establish a realistic earth model termed as TC1P, and data from the Global Land Data Assimilation System (GLDAS hydrology model and Gravity Recovery and Climate Experiment (GRACE data, to generate the hydrology signals assumed in this study. Modeling of surface radial displacements and gravity variation is performed using both TC1P and the global Preliminary Reference Earth Model (PREM. Furthermore, inversions of the hydrology signals based on simulated Global Positioning System (GPS and GRACE data are performed using PREM. Results show that crust in TC1P is harder and softer than that in PREM above and below a depth of 15 km, respectively, causing larger differences in the computed load Love numbers and loading Green's functions. When annual hydrology signals are assumed, the differences of the radial displacements are found to be as large as approximately 0.6 mm for the truncated degree of 180; while for hydrology-trend signals the differences are very small. When annual hydrology signals and the trends are assumed, the differences in the surface gravity variation are very small. It is considered that TC1P can be used to efficiently remove the hydrological effects on the monitoring of crustal movement. It was also found that when PREM is used inappropriately, the inversion of the hydrology signals from simulated annual GPS signals can only recover approximately 88.0% of the annual hydrology signals for the truncated degree of 180, and the inversion of hydrology signals from the simulated trend GPS signals can recover approximately 92.5% for the truncated degree of 90. However, when using the simulated GRACE data, it is possible to recover almost 100%. Therefore, in future, the TC1P model can be used in the inversions of hydrology signals based on GPS network data. PREM is also valid for use with inversions of hydrology signals from GRACE data at resolutions

  17. Particle-in-cell simulations of the solar wind interaction with lunar crustal magnetic anomalies: Magnetic cusp regions

    Science.gov (United States)

    Poppe, A. R.; Halekas, J. S.; Delory, G. T.; Farrell, W. M.

    2012-09-01

    As the solar wind is incident upon the lunar surface, it will occasionally encounter lunar crustal remanent magnetic fields. These magnetic fields are small-scale, highly non-dipolar, have strengths up to hundreds of nanotesla, and typically interact with the solar wind in a kinetic fashion. Simulations, theoretical analyses, and spacecraft observations have shown that crustal fields can reflect solar wind protons via a combination of magnetic and electrostatic reflection; however, analyses of surface properties have suggested that protons may still access the lunar surface in the cusp regions of crustal magnetic fields. In this first report from a planned series of studies, we use a 11/2-dimensional, electrostatic particle-in-cell code to model the self-consistent interaction between the solar wind, the cusp regions of lunar crustal remanent magnetic fields, and the lunar surface. We describe the self-consistent electrostatic environment within crustal cusp regions and discuss the implications of this work for the role that crustal fields may play regulating space weathering of the lunar surface via proton bombardment.

  18. The Crustal Structure of the North-South Earthquake Belt in China Revealed from Deep Seismic Soundings and Gravity Data

    Science.gov (United States)

    Zhao, Yang; Guo, Lianghui; Shi, Lei; Li, Yonghua

    2017-10-01

    The North-South earthquake belt (NSEB) is one of the major earthquake regions in China. The studies of crustal structure play a great role in understanding tectonic evolution and in evaluating earthquake hazards in this region. However, some fundamental crustal parameters, especially crustal interface structure, are not clear in this region. In this paper, we reconstructed the crustal interface structure around the NSEB based on both the deep seismic sounding (DSS) data and the gravity data. We firstly reconstructed the crustal structure of crystalline basement (interface G), interface between upper and lower crusts (interface C) and Moho in the study area by compiling the results of 38 DSS profiles published previously. Then, we forwardly calculated the gravity anomalies caused by the interfaces G and C, and then subtracted them from the complete Bouguer gravity anomalies, yielding the regional gravity anomalies mainly due to the Moho interface. We then utilized a lateral-variable density interface inversion technique with constraints of the DSS data to invert the regional anomalies for the Moho depth model in the study area. The reliability of our Moho depth model was evaluated by comparing with other Moho depth models derived from other gravity inversion technique and receiver function analysis. Based on our Moho depth model, we mapped the crustal apparent density distribution in the study area for better understanding the geodynamics around the NSEB.

  19. Strain-induced stiffening of nanocellulose-reinforced poly(vinyl alcohol) hydrogels mimicking collagenous soft tissues.

    Science.gov (United States)

    Tummala, Gopi Krishna; Joffre, Thomas; Rojas, Ramiro; Persson, Cecilia; Mihranyan, Albert

    2017-05-31

    Soft tissues possess remarkable mechanical strength for their high water content, which is hard to mimic in synthetic materials. Here, we demonstrate how strain-induced stiffening in hydrogels plays a major role in mimicking the mechanical properties of collagenous soft tissues. In particular, nanocellulose reinforced polyvinyl alcohol (PVA) hydrogels of exceptionally high water content (90-93 wt%) are shown to exhibit collagen-like mechanical behavior typical for soft tissues. High water content and co-existence of both soft and rigid domains in the gel network are the main factors responsible for strain-induced stiffening. This observed effect due to the alignment of rigid components of the hydrogel is simulated through modeling and visualized through strain-induced birefringence experiments. Design parameters such as nanocellulose aspect ratio and solvent composition are also shown to be important to control the mechanical properties. In addition, owing to their transparency (90-95% at 550 nm) and hyperelastic properties (250-350% strain), the described hydrogels are promising materials for biomedical applications, especially in ophthalmology.

  20. Flow cytometry as a diagnostic tool in the early diagnosis of aggressive lymphomas mimicking life-threatening infection.

    Science.gov (United States)

    Tsagarakis, Nikolaos J; Kentrou, Nektaria A; Kakiopoulos, Georgios; Androutsos, Georgios; Galanopoulos, Athanasios; Michaelidis, Christos; Rontogianni, Dimitra; Tolis, Apostolos; Chini, Stavroula; Gortzolidis, Georgios; Papadimitriou, Konstantinos A; Skoumi, Dimitra; Tzanetou, Konstantina; Paterakis, Georgios

    2011-01-01

    Aggressive lymphomas can present with symptoms mimicking life-threatening infection. Flow cytometry (FC) is usually recommended for the classification and staging of lymphomas in patients with organomegaly and atypical cells in effusions and blood, after the exclusion of other possible diagnoses. FC may also have a place in the initial diagnostic investigation of aggressive lymphoma. Three cases are presented here of highly aggressive lymphomas in young adults, which presented with the clinical picture of fever of unknown origin (FUO) in patients severely ill. All followed a life-threatening clinical course, and two developed the hemophagocytic syndrome (HPS), but microbiological, immunological, and morphological evaluation and immunohistochemistry (IHC) failed to substantiate an early diagnosis. FC was the technique that provided conclusive diagnostic evidence of lymphoma, subsequently verified by IHC. Our experience with these three cases highlights the potential role of FC as an adjunct methodology in the initial assessment of possible highly aggressive lymphoma presenting with the signs and symptoms of life-threatening infection, although the definitive diagnosis should be established by biopsy. In such cases, FC can contribute to the diagnosis of lymphoma, independently of the presence of HPS.