Science.gov

Sample records for active tracer high-resolution

  1. Quantitative observation of tracer transport with high-resolution PET

    NASA Astrophysics Data System (ADS)

    Kulenkampff, Johannes; Gruendig, Marion; Zakhnini, Abdelhamid; Lippmann-Pipke, Johanna

    2016-04-01

    Transport processes in natural porous media are typically heterogeneous over various scales. This heterogeneity is caused by the complexity of pore geometry and molecular processes. Heterogeneous processes, like diffusive transport, conservative advective transport, mixing and reactive transport, can be observed and quantified with quantitative tomography of tracer transport patterns. Positron Emission Tomography (PET) is by far the most sensitive method and perfectly selective for positron-emitting radiotracers, therefore it is suited as reference method for spatiotemporal tracer transport observations. The number of such PET-applications is steadily increasing. However, many applications are afflicted by the low spatial resolution (3 - 5 mm) of the clinical scanners from cooperating nuclear medical departments. This resolution is low in relation to typical sample dimensions of 10 cm, which are restricted by the mass attenuation of the material. In contrast, our GeoPET-method applies a high-resolution scanner with a resolution of 1 mm, which is the physical limit of the method and which is more appropriate for samples of the size of soil columns or drill cores. This higher resolution is achieved at the cost of a more elaborate image reconstruction procedure, especially considering the effects of Compton scatter. The result of the quantitative image reconstruction procedure is a suite of frames of the quantitative tracer distribution with adjustable frame rates from minutes to months. The voxel size has to be considered as reference volume of the tracer concentration. This continuous variable includes contributions from structures far below the spatial resolution, as far as a detection threshold, in the pico-molar range, is exceeded. Examples from a period of almost 10 years (Kulenkampff et al. 2008a, Kulenkampff et al. 2008b) of development and application of quantitative GeoPET-process tomography are shown. These examples include different transport processes

  2. High-resolution Electrical Resistivity Tomography monitoring of a tracer test in a confined aquifer

    NASA Astrophysics Data System (ADS)

    Wilkinson, P. B.; Meldrum, P. I.; Kuras, O.; Chambers, J. E.; Holyoake, S. J.; Ogilvy, R. D.

    2010-04-01

    A permanent geoelectrical subsurface imaging system has been installed at a contaminated land site to monitor changes in groundwater quality after the completion of a remediation programme. Since the resistivities of earth materials are sensitive to the presence of contaminants and their break-down products, 4-dimensional resistivity imaging can act as a surrogate monitoring technology for tracking and visualising changes in contaminant concentrations at much higher spatial and temporal resolution than manual intrusive investigations. The test site, a municipal car park built on a former gasworks, had been polluted by a range of polycyclic aromatic hydrocarbons and dissolved phase contaminants. It was designated statutory contaminated land under Part IIA of the UK Environmental Protection Act due to the risk of polluting an underlying minor aquifer. Resistivity monitoring zones were established on the boundaries of the site by installing vertical electrode arrays in purpose-drilled boreholes. After a year of monitoring data had been collected, a tracer test was performed to investigate groundwater flow velocity and to demonstrate rapid volumetric monitoring of natural attenuation processes. A saline tracer was injected into the confined aquifer, and its motion and evolution were visualised directly in high-resolution tomographic images in near real-time. Breakthrough curves were calculated from independent resistivity measurements, and the estimated seepage velocities from the monitoring images and the breakthrough curves were found to be in good agreement with each other and with estimates based on the piezometric gradient and assumed material parameters.

  3. Parathyroid imaging: comparison of double-tracer (T1-201, Tc-99m) scintigraphy and high-resolution US

    SciTech Connect

    Gooding, G.A.; Okerlund, M.D.; Stark, D.D.; Clark, O.H.

    1986-10-01

    Parathyroid scintigraphy using a double-tracer (T1-201, Tc-99m) subtraction technique depicted 17 of 23 (74%) parathyroid adenomas in patients with and without previous neck operations. High-resolution (10-MHz) ultrasound (US) depicted 18 (78%) of these adenomas. Average tumor size depicted by US was 17 X 10 X 8 mm (excluding a giant adenoma) and 19 X 10 X 9 mm by scintigraphy. Alone, neither modality was particularly sensitive in the depiction of primary hyperplasia of the parathyroid glands, but combined techniques were more effective than the use of a single modality. With both US and T1-201 scintigraphy, only two of 23 cases of parathyroid adenoma in the neck were missed, and none of the eight cases of secondary hyperplasia were missed. In 11 patients who had previously undergone neck surgery, parathyroid tumors were identified in eight by either US or double-tracer scintigraphy. Preoperative parathyroid imaging with double-tracer scintigraphy and high-resolution US is suggested for patients with hyperparathyroidism, particularly in those patients who have had previous parathyroid surgery.

  4. High-Resolution CFD Simulation of Airflow and Tracer Dispersion in New York City

    SciTech Connect

    Leach, M J; Chan, S T; Lundquist, J K

    2005-11-02

    In 2004, a research project--the New York City Urban Dispersion Program (NYC UDP)--was launched by the Department of Homeland Security with the goal to improve the permanent network of wind stations in and around New York City and to enhance the city's emergency response capabilities. Encompassing both field studies and computer modeling, one of the program's objectives is to improve and validate urban dispersion models using the data collected from field studies and to transfer the improved capabilities to NYC emergency agencies. The first two field studies were conducted in March and August 2005 respectively and an additional study is planned for the summer of 2006. Concurrently model simulations, using simple to sophisticated computational fluid dynamics (CFD) models, have been performed to aid the planning of field studies and also to evaluate the performance of such models. Airflow and tracer dispersion in urban areas such as NYC are extremely complicated. Some of the contributing factors are complex geometry, variable terrain, coupling between local and larger scale flows, deep canyon mixing and updrafts/downdrafts caused by large buildings, street channeling and upstream transport, roof features, and heating effects, etc. Sponsored by the U.S. Department of Energy (DOE) and Department of Homeland Security (DHS), we have developed a CFD model, FEM3MP, to address some of the above complexities. Our model is based on solving the three-dimensional, time-dependent, incompressible Navier-Stokes equations with appropriate physics for modeling airflow and dispersion in the urban environment. Also utilized in the model are finite-element discretization for effective treatment of complex geometries and a semi-implicit projection method for efficient time-integration. A description of the model can be found in Gresho and Chan (1998), Chan and Stevens (2000). Predictions from our model are continuously being verified against data from field studies, such as URBAN 2000

  5. High resolution studies of complex solar active regions

    NASA Astrophysics Data System (ADS)

    Deng, Na

    Flares and Coronal Mass Ejections (CMEs) are energetic events, which can even impact the near-Earth environment and are the principal source of space weather. Most of them originate in solar active regions. The most violent events are produced in sunspots with a complex magnetic field topology. Studying their morphology and dynamics is helpful in understanding the energy accumulation and release mechanisms for flares and CMEs, which are intriguing problems in solar physics. The study of complex active regions is based on high-resolution observations from space missions and new instruments at the Big Bear Solar Observatory (BBSO). Adaptive optics (AO) in combination with image restoration techniques (speckle masking imaging) can achieve improved image quality and a spatial resolution (about 100 km on the solar surface) close to the diffraction limit of BBSO's 65 cm vacuum telescope. Dopplergrams obtained with a two-dimensional imaging spectrometer combined with horizontal flow maps derived with Local Correlation Tracking (LCT) provide precise measurements of the three-dimensional velocity field in sunspots. Magnetic field measurements from ground- and space-based instruments complement these data. At the outset of this study, the evolution and morphology of a typical round sunspot are described in some detail. The sunspot was followed from disk center to the limb, thus providing some insight into the geometry of the magnetic flux system. Having established a benchmark for a stable sunspot, the attention is turned to changes of the sunspot structure associated with flares and CMEs. Rapid penumbral decay and the strengthening of sunspot umbrae are manifestations of photospheric magnetic field changes after a flare. These sudden intensity changes are interpreted as a result of magnetic reconnection during the flare, which causes the magnetic field lines to be turned from more inclined to more vertical. Strong photospheric shear flows along the flaring magnetic

  6. High-Resolution PET Imaging with Therapeutic Antibody-based PD-1/PD-L1 Checkpoint Tracers

    PubMed Central

    Hettich, Michael; Braun, Friederike; Bartholomä, Mark D.; Schirmbeck, Reinhold; Niedermann, Gabriele

    2016-01-01

    Checkpoint-blocking antibodies like those targeting the PD-1/PD-L1 pathway have revolutionized oncology. We developed radiotracers based on therapeutic checkpoint-blocking antibodies permitting sensitive and high-resolution PET imaging of both PD-1 and PD-L1 in immunocompetent mice. ImmunoPET of naive mice revealed similar overall expression patterns for PD-1 and PD-L1 in secondary lymphoid organs (spleen and lymph nodes). Interestingly, PD-L1 was also detected in brown adipose tissue (BAT), confirming the notion that BAT is immunologically relevant. Under pathophysiological conditions, strong expression of the receptor/ligand pair was also found in non-lymphoid tissues. Both were specifically detected in malignant tumors. PD-1 was readily detected after combined immunoradiotherapy causing massive tumor infiltration by PD-1+ lymphocytes. PD-L1 tracer uptake was reduced in PD-L1 knockout tumors. Moreover, monitoring the expression changes of PD-L1 in response to its main inducer, the effector T cell cytokine IFN-γ, revealed robust upregulation in the lung. This suggests that T cell responses in the lung, a vital organ continuously exposed to a variety of antigens, are strongly restrained by the PD-1 checkpoint. In turn, this could explain the association of PD-1 checkpoint inhibition with potentially fatal immune-mediated pneumonitis and partially also its efficacy in lung cancer. PMID:27446497

  7. High resolution X-ray spectroscopy of active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Krolik, Julian H.

    1990-01-01

    After a brief review of the principal problems of AGN research, selected potential high-resolution observations are discussed with a view toward assessing their scientific value and the degree of resolution they will require. Two classes of observations pertaining directly to AGNs are discussed. Fe K-alpha spectroscopy relevant to the dynamical and thermal character of the emission line zones; and measurement of resonance line absorption by highly-ionized species in BL Lac objects, which should provide information about entrainment of interstellar material by relativistic jets. A third class of potentially important observations uses AGNs as background light sources in order to directly measure the distance to clusters of galaxies.

  8. Investigation of Contaminant Transport and Dispersion in New York Harbor by a High Resolution SF6 Tracer Study

    NASA Astrophysics Data System (ADS)

    Caplow, T.; Schlosser, P.; Ho, D. T.

    2002-12-01

    Sulfur hexafluoride (SF6) has been used successfully as a deliberate tracer for rivers, estuaries, and coastal areas, due to its inert nature, non-toxicity, and extremely low detection limit. An automated, high-resolution SF6 measurement system mounted on a boat was recently developed for several projects on the Hudson River. The system has a sampling interval of two minutes and a detection limit of 1 x 10-14 mol L-1. Real-time data visualization enables revisions of sampling strategy during the experiment. A single injection has allowed observation of advection rates, dispersion processes, and air-water gas exchange for up to two weeks, and longer experiments are possible. This equipment, with minor modifications, was applied to New York Harbor in July 2002. New York Harbor is one of the busiest seaports in the United States, processing nearly \\100 billion in cargo each year. Most of the shipping facilities are located in Newark Bay (approximately 15 km^{2}) or in two adjacent channels: the Kill van Kull (6 km long) and the Arthur Kill (20 km long). Newark Bay, which is mostly saline, is fed by the Hackensack and Passaic Rivers, both of which flow through heavily industrialized areas. Ultimately, these waters drain through the Kills to Raritan Bay and the Atlantic Ocean. Due to a combination of point sources, runoff, wastewater treatment plants, and emissions from the shipping industry, Newark Bay and the Kills receive a large volume and variety of contaminants, including petroleum, heavy metals, PCBs, and dioxins. In addition, much of the area is subject to ongoing and extensive navigational dredging, causing widespread re-suspension of previously deposited contaminants. A small quantity (ca. 2 mols) of SF_{6}$ was injected into northern Newark Bay to investigate the spreading of water throughout the Bay, the Kills, and the tidal portions of the Passaic and Hackensack Rivers. The tracer was successfully monitored across most of this area for 12 consecutive days

  9. High-resolution eye tracking using V1 neuron activity

    PubMed Central

    McFarland, James M.; Bondy, Adrian G.; Cumming, Bruce G.; Butts, Daniel A.

    2014-01-01

    Studies of high-acuity visual cortical processing have been limited by the inability to track eye position with sufficient accuracy to precisely reconstruct the visual stimulus on the retina. As a result, studies on primary visual cortex (V1) have been performed almost entirely on neurons outside the high-resolution central portion of the visual field (the fovea). Here we describe a procedure for inferring eye position using multi-electrode array recordings from V1 coupled with nonlinear stimulus processing models. We show that this method can be used to infer eye position with one arc-minute accuracy – significantly better than conventional techniques. This allows for analysis of foveal stimulus processing, and provides a means to correct for eye-movement induced biases present even outside the fovea. This method could thus reveal critical insights into the role of eye movements in cortical coding, as well as their contribution to measures of cortical variability. PMID:25197783

  10. High-Resolution Observations of a Filament showing Activated Barb

    NASA Astrophysics Data System (ADS)

    Joshi, Anand; Martin, Sara F.; Mathew, Shibu; Srivastava, Nandita

    2012-07-01

    Analysis of a filament showing an activated barb using observations from the Dutch Open Telescope (DOT) on 2010 August 20 are presented. The DOT takes Doppler images in Hα, among other wavelengths, in a region about 110 × 110 arcsec^{2} in area, at a cadence of 30~seconds. The offline image restoration technique of speckle reconstruction is applied to obtain diffraction limited images. The filament developed a new barb in 10~minutes, which disappeared within the next 35~minutes. Such a rapid formation and disappearance of a filament barb is unusual, and has not been reported earlier. Line-of-sight velocity maps were constructed from the Doppler images of the target filament. We observe flows in the filament spine towards the barb location prior to its formation, and flows in the barb towards the spine during its disappearance. Photospheric magnetograms from Heliospheric Magnetic Imager on board the Solar Dynamics Observatory, at a cadence of 45~seconds, were used to determine the changes in magnetic flux in the region surrounding the barb location. The variation of magnetic flux in this duration supports the view that barbs are rooted in minor magnetic polarity. Our analysis shows that barbs can be short-lived and formation and disappearance of the barb was associated with cancellation of magnetic flux.

  11. Using High Resolution Tracer Data to Constrain Storage and Flux Estimates in a Spatially Distributed Rainfall-runoff Model

    NASA Astrophysics Data System (ADS)

    Van Huijgevoort, M.; Tetzlaff, D.; Sutanudjaja, E.; Soulsby, C.

    2015-12-01

    Models simulating both stream flow and conservative tracers can provide a more realistic representation of flow paths, storage distributions and mixing processes that is advantageous for many predictions. Conceptual models with such integration have provided useful insights, but tend to be lumped and thus crude representations of catchment processes. Using tracers to aid spatially-distributed models has considerable potential to improve the conceptualisation of the dynamics of internal hydrological stores and fluxes. Here, we examine the strengths and weaknesses of a data-driven, spatially-distributed tracer-aided rainfall-runoff model. The model structure allows the assessment of the effect of landscape properties on the routing and mixing of water and tracers. The model was applied to an experimental site (3.2 km2) in the Scottish Highlands with a unique tracer data set; 4 years of daily isotope ratios in stream water and precipitation were available, as well as 2 years of weekly soil and ground water isotopes. The model evolved from an empirically-based, lumped tracer-aided model previously developed for the catchment. The best model runs were selected from Monte Carlo simulations based on a dual calibration criterion that included objective functions for both stream water isotopes and discharge at the outlet. Model results were also tested against observed spatially-distributed soil water isotope data. Model performance for both criteria was good and the model could reproduce the variable isotope signals in steeper hillslopes where storage was low and damped isotope responses in valley bottom cells with high storage. The model also allows us to estimate the age distributions of internal water fluxes and stream flow and has substantially improved spatial and temporal dynamics of process representation. This gives a more robust framework for projecting the effects of environmental change.

  12. Effect of different transport observations on inverse modeling results: case study of a long-term groundwater tracer test monitored at high resolution

    PubMed Central

    Rasa, Ehsan; Foglia, Laura; Mackay, Douglas M.; Scow, Kate M.

    2014-01-01

    Conservative tracer experiments can provide information useful for characterizing various subsurface transport properties. This study examines the effectiveness of three different types of transport observations for sensitivity analysis and parameter estimation of a three-dimensional site-specific groundwater flow and transport model: conservative tracer breakthrough curves (BTCs), first temporal moments of BTCs (m1), and tracer cumulative mass discharge (Md) through control planes combined with hydraulic head observations (h). High-resolution data obtained from a 410-day controlled field experiment at Vandenberg Air Force Base, California (USA), have been used. In this experiment, bromide was injected to create two adjacent plumes monitored at six different transects (perpendicular to groundwater flow) with a total of 162 monitoring wells. A total of 133 different observations of transient hydraulic head, 1,158 of BTC concentration, 23 of first moment, and 36 of mass discharge were used for sensitivity analysis and parameter estimation of nine flow and transport parameters. The importance of each group of transport observations in estimating these parameters was evaluated using sensitivity analysis, and five out of nine parameters were calibrated against these data. Results showed the advantages of using temporal moment of conservative tracer BTCs and mass discharge as observations for inverse modeling. PMID:24672283

  13. 78 FR 7402 - Small Takes of Marine Mammals Incidental to Specified Activities; Cape Wind's High Resolution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-01

    ...NMFS has received an application from Cape Wind Associates (CWA) for an Incidental Harassment Authorization (IHA) to take marine mammals, by harassment, incidental to pre-construction high resolution survey activities. CWA began pre-construction activities last year, but was unable to complete the entire survey. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments......

  14. Very high resolution UV and X-ray spectroscopy and imagery of solar active regions

    NASA Technical Reports Server (NTRS)

    Bruner, M.; Brown, W. A.; Haisch, B. M.

    1987-01-01

    A scientific investigation of the physics of the solar atmosphere, which uses the techniques of high resolution soft X-ray spectroscopy and high resolution UV imagery, is described. The experiments were conducted during a series of three sounding rocket flights. All three flights yielded excellent images in the UV range, showing unprecedented spatial resolution. The second flight recorded the X-ray spectrum of a solar flare, and the third that of an active region. A normal incidence multi-layer mirror was used during the third flight to make the first astronomical X-ray observations using this new technique.

  15. Preparation of fluorescent labeled gentamicin as biological tracer and its characterization by liquid chromatography and high resolution mass spectrometry.

    PubMed

    Woiwode, Ulrich; Sievers-Engler, Adrian; Lämmerhofer, Michael

    2016-03-20

    This work deals with the preparation of single-labeled bioconjugates of the antibiotic Gentamicin (GT) with the sulforhodamine-derived fluorescence dye Texas Red(®)-X (TR), its purification by high-performance liquid chromatography (HPLC) and its characterization by high-resolution mass spectrometry. Aminoglycosides such as GT are efficient antibiotics, but also problematic due to severe side effects such as nephro- and ototoxicity. Fluorescent labeled GT is used to visualize cellular uptake and distribution of the antibiotic to finally understand the mechanisms of serious adverse drug reactions. Pharmaceutically administered GT is a mixture of mainly four different components, which exhibit three (GT(C1)) or four (GT(C1a), GT(C2), GT(C2a)) primary amino functional groups which can be coupled with the labeling reagent TR. Thus, multiple labeling could be envisaged which was assumed to be detrimental for uptake studies by fluorescence imaging. The proposed synthesis aimed at preparation of single labeled product and together with the employed purification strategy indeed yielded single labeled GT as product. Analytical control of the reaction product was carried out by means of mass spectrometry (UHPLC-ESI-QTOF-MS/MS) to rule out over-labeling of GT, which would alter the physicochemical characteristics of GT and its cellular uptake significantly. Moreover, LC-MS/MS analysis gave valuable insights into structural diversity of single labeled products. Further, high-resolution MS and MS/MS spectra of underivatized GT are provided as well. The analytical information on preparation strategy and structure diversity is valuable for studies with a clinical focus on research of aminoglycoside toxicity. Furthermore, it is deemed to be useful for the development of LC-MS/MS assays for the determination of aminoglycosides or the fast screening of synthetic biology samples from biotechnological drug discovery. PMID:26775580

  16. 76 FR 56735 - Small Takes of Marine Mammals Incidental to Specified Activities; Cape Wind's High Resolution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ...NMFS has received a complete and adequate application from Cape Wind Associates for an Incidental Harassment Authorization (IHA) to take marine mammals, by harassment, incidental to pre-construction high resolution survey activities. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is proposing to issue an IHA to Cape Wind Associates to incidentally harass, by Level B harassment, five......

  17. Comparison of interfacial partitioning tracer test and high-resolution microtomography measurements of fluid-fluid interfacial areas for an ideal porous medium

    NASA Astrophysics Data System (ADS)

    Narter, Matt; Brusseau, Mark L.

    2010-08-01

    Fluid-fluid interfacial area for porous media systems can be measured with the aqueous phase interfacial partitioning tracer test (IPTT) method or with high-resolution microtomography. The results of prior studies have shown that interfacial areas measured with the IPTT method are larger than values measured with microtomography. The observed disparity has been hypothesized to result from the impact of porous medium surface roughness on film-associated interfacial area, wherein the influence of surface roughness is characterized to some extent by the IPTT method but not by microtomography due to resolution constraints. This hypothesis was tested by using the two methods to measure interfacial area between an organic immiscible liquid and water for an ideal glass beads medium that has no measurable surface roughness. The tracer tests yielded a mean interfacial area of 2.8 (±5 cm-1), while microtomography produced an interfacial area of 2.7 (±2 cm-1). Maximum specific interfacial areas, equivalent to areas normalized by nonwetting fluid volume, were calculated and compared to measures of the specific solid surface area. The normalized interfacial areas were similar to the specific solid surface area calculated using the smooth sphere assumption and to the specific solid surface area measured using the N2/Brunauer, Emmett, and Teller (BET) method. The results presented herein indicate that both the IPTT and microtomography methods provide robust characterization of fluid-fluid interfacial area and that they are comparable in the absence of the impact of surface roughness.

  18. COMPARISON OF INTERFACIAL PARTITIONING TRACER TEST AND HIGH-RESOLUTION MICROTOMOGRAPHY MEASUREMENTS OF FLUID-FLUID INTERFACIAL AREAS FOR AN IDEAL POROUS MEDIUM.

    PubMed

    Narter, Matt; Brusseau, Mark L

    2010-08-01

    Fluid-fluid interfacial area for porous-media systems can be measured with the aqueous-phase interfacial partitioning tracer test (IPTT) method or with high-resolution microtomography. The results of prior studies have shown that interfacial areas measured with the IPTT method are larger than values measured with microtomography. The observed disparity has been hypothesized to result from the impact of porous-medium surface roughness on film-associated interfacial area, wherein the influence of surface roughness is characterized to some extent by the IPTT method but not by microtomography due to resolution constraints. This hypothesis was tested by using the two methods to measure interfacial area between an organic immiscible liquid and water for an ideal glass-beads medium that has no measurable surface roughness. The tracer tests yielded a mean interfacial area of 2.8 (± 5 cm(-1)), while microtomography produced an interfacial area of 2.7 (± 2 cm(-1)). Maximum specific interfacial areas, equivalent to areas normalized by non-wetting fluid volume, were calculated and compared to measures of the specific solid surface area. The normalized interfacial areas were similar to the specific solid surface area calculated using the smooth-sphere assumption, and to the specific solid surface area measured using the N2/BET method. The results presented herein indicate that both the IPTT and microtomography methods provide robust characterization of fluid-fluid interfacial area, and that they are comparable absent the impact of surface roughness. PMID:24604925

  19. Interactive Change Detection Using High Resolution Remote Sensing Images Based on Active Learning with Gaussian Processes

    NASA Astrophysics Data System (ADS)

    Ru, Hui; Yu, Huai; Huang, Pingping; Yang, Wen

    2016-06-01

    Although there have been many studies for change detection, the effective and efficient use of high resolution remote sensing images is still a problem. Conventional supervised methods need lots of annotations to classify the land cover categories and detect their changes. Besides, the training set in supervised methods often has lots of redundant samples without any essential information. In this study, we present a method for interactive change detection using high resolution remote sensing images with active learning to overcome the shortages of existing remote sensing image change detection techniques. In our method, there is no annotation of actual land cover category at the beginning. First, we find a certain number of the most representative objects in unsupervised way. Then, we can detect the change areas from multi-temporal high resolution remote sensing images by active learning with Gaussian processes in an interactive way gradually until the detection results do not change notably. The artificial labelling can be reduced substantially, and a desirable detection result can be obtained in a few iterations. The experiments on Geo-Eye1 and WorldView2 remote sensing images demonstrate the effectiveness and efficiency of our proposed method.

  20. Recent high-resolution seismic reflection studies of active faults in the Puget Lowland

    NASA Astrophysics Data System (ADS)

    Liberty, L. M.; Pratt, T. L.

    2005-12-01

    In the past four years, new high-resolution seismic surveys have filled in key gaps in our understanding of active structures beneath the Puget Lowland, western Washington State. Although extensive regional and high-resolution marine seismic surveys have been fundamental to understanding the tectonic framework of the area, these marine profiles lack coverage on land and in shallow or restricted waterways. The recent high-resolution seismic surveys have targeted key structures beneath water bodies that large ships cannot navigate, and beneath city streets underlain by late Pleistocene glacial deposits that are missing from the waterways. The surveys can therefore bridge the gap between paleoseismic and marine geophysical studies, and test key elements of models proposed by regional-scale geophysical studies. Results from these surveys have: 1) documented several meters of vertical displacement on at least two separate faults in the Olympia area; 2) clarified the relationship between the Catfish Lake scarp and the underlying kink band in the Tacoma fault zone; 3) provided a first look at the structures beneath the north portion of the western Tacoma fault zone, north of previous marine profiles; 4) documented that deformation along the Seattle fault extends well east of Lake Sammamish; 5) imaged the Seattle fault beneath the Vasa Park trench; and 6) documented multiple fault strands in and south of the Seattle fault zone south of Bellevue. The results better constrain interpretations of paleoseismic investigations of past earthquakes on these faults, and provide targets for future paleoseismic studies.

  1. Tracer-aided modelling using long-term and high resolution data to assess non-stationarity in stream water age

    NASA Astrophysics Data System (ADS)

    Soulsby, C.; Birkel, C.; Tetzlaff, D.

    2015-12-01

    Understanding how water and solutes move through watersheds and the associated travel times remains a key research frontier in hydrology. Here we integrate long-term data (6 years of weekly isotope measurements in rainfall and runoff) into a tracer-aided conceptual modelling approach to provide fresh insights into the complex interrelationships between catchment storage dynamics, hydrological connectivity and resulting non-stationary stream water ages. We show that in a wet Scottish upland catchment dominated by runoff generation from riparian peats (histosols) with high water storage capacity, the storage dynamics of different landscape units (e.g. hillslope vs. riparian zones) regulate both mixing processes and the strength of hydrological connectivity that govern water and solute fluxes and determine catchment travel times. We also found that the frequency and longevity of hydrological connectivity and the associated relative importance of dynamic flow paths control the contribution of younger (< 1 month) or older (>4 years) waters to the stream. Water and solute transport is mainly facilitated by overland flow from saturated histosols connected to the stream network even during smaller events. However, during prolonged dry periods, near-surface runoff "switches off" and stream water is dominated by older groundwater. The saturated riparian soils represent large mixing zones that buffer the time variance of water age and act as "isostats" damping variable inputs. These zones also integrate catchment-scale partial mixing processes. Although simulations depend on model performance, which is influenced by stochastic variation in isotope inputs, a longer-term storage analysis using this tracer-aided model allowed us to examine the sensitivity of the catchment response and transit times to extreme hydroclimatic variability. These insights were validated using a more recent high resolution dataset (3 years of daily isotope data) which also improved constraints on

  2. Tracer motion in an active dumbbell fluid

    NASA Astrophysics Data System (ADS)

    Suma, Antonio; Cugliandolo, Leticia F.; Gonnella, Giuseppe

    2016-05-01

    The diffusion properties of spherical tracers coupled through a repulsive potential to a system of active dumbbells are analyzed. We model the dumbbells’ dynamics with Langevin equations and the activity with a self-propulsive force of constant magnitude directed along the main axis of the molecules. Two types of tracers are considered. Thermal tracers are coupled to the same bath as the dumbbells while athermal tracers are not; both interact repulsively with the dumbbells. We focus our attention on the intruders’ mean square displacement and how it compares to the one of the dumbbells. We show that the dynamics of thermal intruders, with mass similar to the one of the dumbbells, display the typical four time-lag regimes of the dumbbells’ mean square displacement. The thermal tracers’ late-time diffusion coefficient depends on their mass very weakly and it is close to the one of the dumbbells at low Péclet only. Athermal tracers only have ballistic and late-time diffusive regimes. The late time diffusion coefficients of athermal tracers and dumbbells have similar values at high Péclet number when their masses are of the same order, while at low Péclet number this coefficient gets close to the one of the dumbbells only when the tracers are several order of magnitude heavier than the dumbbells. We propose a generalization of the Enskog law for dilute hard disks, that describes the athermal tracers’ mean square displacement in the form of a scaling law in terms of their mass.

  3. Coordinated Observations of X-ray and High-resolution EUV Active Region Dynamics

    NASA Technical Reports Server (NTRS)

    Savage, Sabrina

    2013-01-01

    The recently-launched High-resolution Coronal imager (Hi-C) sounding rocket provided the highest resolution images of coronal loops and other small-scale structures in the 193 Angstrom passband to date. With just 5 minutes of observations, the instrument recorded a variety of dynamic coronal events -- including even a small B-class flare. We will present our results comparing these extreme-ultraviolet (EUV) observations with X-ray imaging from Hinode/XRT as well as EUV AIA data to identify sources of hot plasma rooted in the photosphere and track their affect on the overall topology and dynamics of the active region.

  4. Coordinated Observations of X-ray and High-Resolution EUV Active Region Dynamics

    NASA Technical Reports Server (NTRS)

    Savage, Sabrina; Cirtain, Jonathan; Winebarger, Amy; Kobayashi, Ken; Golub, Leon; Korreck, Kelly

    2013-01-01

    The recently-launched High-resolution Coronal imager (Hi-C) sounding rocket provided the highest resolution images of coronal loops and other small-scale structures in the 193 Angstrom passband to date. With just 5 minutes of observations, the instrument recorded a variety of dynamic coronal events -- including even a small B-class flare. We will present our results comparing these extreme-ultraviolet (EUV) observations with X-ray imaging from Hinode/XRT as well as EUV AIA data to identify sources of hot plasma rooted in the photosphere and track their affect on the overall topology and dynamics of the active region.

  5. High-resolution X-ray spectroscopy of four active galaxies - Probing the intercloud medium

    NASA Technical Reports Server (NTRS)

    Lum, Kenneth S. K.; Canizares, Claude R.; Markert, Thomas H.; Arnaud, Keith A.

    1990-01-01

    The focal plane crystal spectrometer (FPCS) on the Einstein Observatory has been used to perform a high-resolution spectroscopic search for oxygen X-ray line emission from four active galaxies: Fairall 9, Mrk 421, Mrk 501, and PKS 0548 - 322. Specifically, O VIII Ly-alpha and Ly-beta, whose unredshifted energies are 653 and 775 eV, respectively, were sought. No narrow-line emission was detected within the energy bands searched. Upper limits are calculated on the line flux from these sources of 30 eV equivalent width and use a photoionization model to place corresponding upper limits on the densities of diffuse gas surrounding the active nuclei. The upper limits on gas density range from about 0.02-50/cu cm and probe various radial distances from the central source. This is the first time high-resolution X-ray spectroscopy has been used to place constraints on the intercloud medium in active galaxies.

  6. High resolution DEM from Tandem-X interferometry: an accurate tool to characterize volcanic activity

    NASA Astrophysics Data System (ADS)

    Albino, Fabien; Kervyn, Francois

    2013-04-01

    Tandem-X mission was launched by the German agency (DLR) in June 2010. It is a new generation high resolution SAR sensor mainly dedicated to topographic applications. For the purpose of our researches focused on the study of the volcano-tectonic activity in the Kivu Rift area, a set of Tandem-X bistatic radar images were used to produce a high resolution InSAR DEM of the Virunga Volcanic Province (VVP). The VVP is part of the Western branch of the African rift, situated at the boundary between D.R. Congo, Rwanda and Uganda. It has two highly active volcanoes, Nyiragongo and Nyamulagira. A first task concerns the quantitative assessment of the vertical accuracy that can be achieved with these new data. The new DEMs are compared to other space borne datasets (SRTM, ASTER) but also to field measurements given by differential GPS. Multi-temporal radar acquisitions allow us to produce several DEM of the same area. This appeared to be very useful in the context of an active volcanic context where new geomorphological features (faults, fissures, volcanic cones and lava flows) appear continuously through time. For example, since the year 2000, time of the SRTM acquisition, we had one eruption at Nyiragongo (2002) and six eruptions at Nyamulagira (2001, 2002, 2004, 2006, 2010 and 2011) which all induce large changes in the landscape with the emplacement of new lava fields and scoria cones. From our repetitive Tandem-X DEM production, we have a tool to identify and also quantify in term of size and volume all the topographic changes relative to this past volcanic activity. These parameters are high value information to improve the understanding of the Virunga volcanoes; the accurate estimation of erupted volume and knowledge of structural features associated to past eruptions are key parameters to understand the volcanic system, to ameliorate the hazard assessment, and finally contribute to risk mitigation in a densely populated area.

  7. High-Resolution Seismic Reflection Studies of Active Faults: a Case Study from Washington State

    NASA Astrophysics Data System (ADS)

    Liberty, L. M.; Pratt, T. L.

    2007-12-01

    In the past five years, new high-resolution seismic surveys have filled in gaps in our understanding of active structures beneath the Puget Lowland region of Washington State. The extensive forests have made recognition of active faults difficult, but new Light Distance and Ranging (LIDAR) detailed topographic data have made a major breakthrough in mapping active faults. Extensive regional and high-resolution marine seismic surveys have been fundamental to understanding the tectonic framework of the area. These marine profiles, however, lack coverage beneath water bodies that large ships cannot navigate and beneath city streets underlain by late Pleistocene glacial deposits that are missing from the waterways. Recent land surveys and profiles in restricted waterways can therefore bridge the gap between paleoseismic and marine geophysical studies, and test elements of models proposed by regional-scale geophysical studies. We have also been venturing into more congested areas to seismically image faults in key urban locations. Results from recent surveys have: 1) documented new faults that had long been suspected in the Olympia area; 2) clarified the relationship between the LIDAR scarps and observed structures across the Tacoma fault zone; 3) provided a window into structures beneath the north and eastern portions of the western Tacoma fault zone; 4) documented deformation along the Seattle fault near a paleoseismic trench; 5) mapped the eastern part the Seattle fault zone beyond its previously mapped limits; and 6) documented multiple fault strands in the Seattle fault zone in the cities of Bellevue and Seattle. The results better constrain interpretations of paleoseismic data collected on these faults, and provide targets for future paleoseismic studies.

  8. Vertical diffusivities of active and passive tracers

    NASA Astrophysics Data System (ADS)

    Canuto, V. M.; Cheng, Y.; Howard, A. M.

    The climate models that include a carbon-cycle need the vertical diffusivity of a passive tracer. Since an expression for the latter is not available, it has been common practice to identify it with that of salt. The identification is questionable since T, S are active, not passive tracers. We present the first derivation of the diffusivity of a passive tracer in terms of Ri (Richardson number) and R ρ (density ratio, ratio of salinity over temperature z-gradients). The following results have emerged: The passive tracer diffusivity is an algebraic function of Ri, R ρ. In doubly stable regimes (DS, ∂ T/∂z > 0, ∂S/∂ z < 0), the passive scalar diffusivity is nearly the same as that of salt/heat for any values of R ρ < 0 and Ri > 0. In DC regimes (diffusive convection, ∂ T/∂ z < 0, ∂ S/∂ z < 0, R ρ > 1), the passive scalar diffusivity is larger than that of salt. At Ri = O(1), it can be more than twice as large. In SF regimes (salt fingers, ∂ T/∂ z > 0, ∂ S/∂ z > 0, R ρ < 1), the passive scalar diffusivity is smaller than that of salt. At Ri = O(1), it can be less than half of it. The passive tracer diffusivity predicted at the location of NATRE (North Atlantic Tracer Release Experiment) is discussed. Perhaps the most relevant conclusion is that the common identification of the tracer diffusivity with that of salt is valid only in DS regimes. In the Southern Ocean, where there is the largest CO 2 absorption, the dominant regime is diffusive convection discussed in (c) above.

  9. Vertical Diffusivities of Active and Passive Tracers

    NASA Technical Reports Server (NTRS)

    Canuto, V. M.; Cheng, Y.; Howard, A. M.

    2010-01-01

    The climate models that include a carbon-cycle need the vertical diffusivity of a passive tracer. Since an expression for the latter is not available, it has been common practice to identify it with that of salt. The identification is questionable since T, S are active, not passive tracers. We present the first derivation of the diffusivity of a passive tracer in terms of Ri (Richardson number) and Rq (density ratio, ratio of salinity over temperature z-gradients). The following results have emerged: (a) The passive tracer diffusivity is an algebraic function of Ri, Rq. (b) In doubly stable regimes (DS, partial derivative of T with respect to z > 0, partial derivative of S with respect to z < 0), the passive scalar diffusivity is nearly the same as that of salt/heat for any values of Rq < 0 and Ri > 0. (c) In DC regimes (diffusive convection, partial derivative of T with respect to z < 0, partial derivative of S with respect to z < 0, Rq > 1), the passive scalar diffusivity is larger than that of salt. At Ri = O(1), it can be more than twice as large. (d) In SF regimes (salt fingers, partial derivative of T with respect to z > 0, partial derivative of S with respect to z > 0, Rq < 1), the passive scalar diffusivity is smaller than that of salt. At Ri = O(1), it can be less than half of it. (e) The passive tracer diffusivity predicted at the location of NATRE (North Atlantic Tracer Release Experiment) is discussed. (f) Perhaps the most relevant conclusion is that the common identification of the tracer diffusivity with that of salt is valid only in DS regimes. In the Southern Ocean, where there is the largest CO2 absorption, the dominant regime is diffusive convection discussed in (c) above.

  10. Chromospheric activity on late-type star DM UMa using high-resolution spectroscopic observations

    NASA Astrophysics Data System (ADS)

    Zhang, LiYun; Pi, QingFeng; Han, Xianming L.; Chang, Liang; Wang, Daimei

    2016-06-01

    We present new 14 high-resolution echelle spectra to discuss the level of chromospheric activity of DM UMa in {He I} D3, {Na I} D1, D2, Hα, and {Ca II} infrared triplet lines (IRT). It is the first time to discover the emissions above the continuum in the {He I} D3 lines on 2015 February 9 and 10. The emission on February 9 is the strongest one ever detected for DM UMa. We analysed these chromospheric active indicators by employing the spectral subtraction technique. The subtracted spectra reveal weak emissions in the {Na I} D1, D2 lines, strong emission in the Hα line, and clear excess emissions in the {Ca II} IRT lines. Our values for the EW8542/EW8498 ratio are on the low side, in the range of 1.0-1.7. There are also clear phase variations of the level of chromospheric activity in equivalent width (EW) light curves in these chromospheric active lines (especially the Hα line). These phenomena might be explained by flare events or rotational modulations of the level of chromospheric activity.

  11. Calibration activities on the BepiColombo High-Resolution Channel (HRIC) of SIMBIO-SYS instrument

    NASA Astrophysics Data System (ADS)

    Della Corte, V.; Zusi, M.; Palumbo, P.; Baroni, M.; Ficai Veltroni, I.; Flamini, E.; Mugnuolo, R.

    2015-10-01

    HRIC (High Resolution Imaging Channel) is the high resolution channel of the SIMBIO-SYS instrument on- board the ESA BepiColombo Mission. Calibration activities were performed at SelexES premises in spring- summer 2014 in order to check for Channel performances (radiometric performances, quality image and geometrical performances) and to obtain data necessary to setup a calibration pipeline necessary to process the raw images acquired by the channel when in operative scenario.

  12. Active faults in the deformation zone off Noto Peninsula, Japan, revealed by high- resolution seismic profiles

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Okamura, Y.; Murakami, F.; Kimura, H.; Ikehara, K.

    2008-12-01

    Recently, a lot of earthquakes occur in Japan. The deformation zone which many faults and folds have concentrated exists on the Japan Sea side of Japan. The 2007 Noto Hanto Earthquake (MJMA 6.9) and 2007 Chuetsu-oki Earthquake (MJMA 6.8) were caused by activity of parts of faults in this deformation zone. The Noto Hanto Earthquake occurred on 25 March, 2007 under the northwestern coast of Noto Peninsula, Ishikawa Prefecture, Japan. This earthquake is located in Quaternary deformation zone that is continued from northern margin of Noto Peninsula to southeast direction (Okamura, 2007a). National Institute of Advanced Industrial Science and Technology (AIST) carried out high-resolution seismic survey using Boomer and 12 channels short streamer cable in the northern part off Noto Peninsula, in order to clarify distribution and activities of active faults in the deformation zone. A twelve channels short streamer cable with 2.5 meter channel spacing developed by AIST and private corporation is designed to get high resolution seismic profiles in shallow sea area. The multi-channel system is possible to equip on a small fishing boat, because the data acquisition system is based on PC and the length of the cable is short and easy to handle. Moreover, because the channel spacing is short, this cable is very effective for a high- resolution seismic profiling survey in the shallow sea, and seismic data obtained by multi-channel cable can be improved by velocity analysis and CDP stack. In the northern part off Noto Peninsula, seismic profiles depicting geologic structure up to 100 meters deep under sea floor were obtained. The most remarkable reflection surface recognized in the seismic profiles is erosion surface at the Last Glacial Maximum (LGM). In the western part, sediments about 30 meters (40 msec) thick cover the erosional surface that is distributed under the shelf shallower than 100m in depth and the sediments thin toward offshore and east. Flexures like deformation in

  13. Thermal Stability of Chelated Indium Activable Tracers

    SciTech Connect

    Chrysikopoulos, Costas; Kruger, Paul

    1986-01-21

    The thermal stability of indium tracer chelated with organic ligands ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) was measured for reservoir temperatures of 150, 200, and 240 C. Measurements of the soluble indium concentration was made as a function of time by neutron activation analysis. From the data, approximate thermal decomposition rates were estimated. At 150 C, both chelated tracers were stable over the experimental period of 20 days. At 200 C, the InEDTA concentration remained constant for 16 days, after which the thermal decomposition occurred at a measured rate constant of k = 0.09 d{sup -1}. The thermal decomposition of InNTA at 200 C showed a first order reaction with a measured rate constant of k = 0.16 d{sup -1}. At 240 C, both indium chelated tracers showed rapid decomposition with rate constants greater than 1.8 d{sup -1}. The data indicate that for geothermal reservoir with temperatures up to about 200 C, indium chelated tracers can be used effectively for transit times of at least 20 days. These experiments were run without reservoir rock media, and do not account for concomitant loss of indium tracer by adsorption processes.

  14. A System and Method for Online High-Resolution Mapping of Gastric Slow-Wave Activity

    PubMed Central

    Bull, Simon H.; O’Grady, Gregory; Du, Peng

    2015-01-01

    High-resolution (HR) mapping employs multielectrode arrays to achieve spatially detailed analyses of propagating bioelectrical events. A major current limitation is that spatial analyses must currently be performed “off-line” (after experiments), compromising timely recording feedback and restricting experimental interventions. These problems motivated development of a system and method for “online” HR mapping. HR gastric recordings were acquired and streamed to a novel software client. Algorithms were devised to filter data, identify slow-wave events, eliminate corrupt channels, and cluster activation events. A graphical user interface animated data and plotted electrograms and maps. Results were compared against off-line methods. The online system analyzed 256-channel serosal recordings with no unexpected system terminations with a mean delay 18 s. Activation time marking sensitivity was 0.92; positive predictive value was 0.93. Abnormal slow-wave patterns including conduction blocks, ectopic pacemaking, and colliding wave fronts were reliably identified. Compared to traditional analysis methods, online mapping had comparable results with equivalent coverage of 90% of electrodes, average RMS errors of less than 1 s, and CC of activation maps of 0.99. Accurate slow-wave mapping was achieved in near real-time, enabling monitoring of recording quality and experimental interventions targeted to dysrhythmic onset. This work also advances the translation of HR mapping toward real-time clinical application. PMID:24860024

  15. High-resolution observations of active region moss and its dynamics

    SciTech Connect

    Morton, R. J.; McLaughlin, J. A.

    2014-07-10

    The High Resolution Coronal Imager has provided the sharpest view of the EUV corona to date. In this paper, we exploit its impressive resolving power to provide the first analysis of the fine-scale structure of moss in an active region. The data reveal that the moss is made up of a collection of fine threads that have widths with a mean and standard deviation of 440 ± 190 km (FWHM). The brightest moss emission is located at the visible head of the fine-scale structure and the fine structure appears to extend into the lower solar atmosphere. The emission decreases along the features, implying that the lower sections are most likely dominated by cooler transition region plasma. These threads appear to be the cool, lower legs of the hot loops. In addition, the increased resolution allows for the first direct observation of physical displacements of the moss fine structure in a direction transverse to its central axis. Some of these transverse displacements demonstrate periodic behavior, which we interpret as a signature of kink (Alfvénic) waves. Measurements of the properties of the transverse motions are made and the wave motions have means and standard deviations of 55 ± 37 km for the transverse displacement amplitude, 77 ± 33 s for the period, and 4.7 ± 2.5 km s{sup –1} for the velocity amplitude. The presence of waves in the transition region of hot loops could have important implications for the heating of active regions.

  16. Automated Gastric Slow Wave Cycle Partitioning and Visualization for High-resolution Activation Time Maps

    PubMed Central

    Erickson, Jonathan C.; O’Grady, Greg; Du, Peng; Egbuji, John U.; Pullan, Andrew J.; Cheng, Leo K.

    2014-01-01

    High-resolution (HR) multi-electrode mapping has become an important technique for evaluating gastrointestinal (GI) slow wave (SW) behaviors. However, the application and uptake of HR mapping has been constrained by the complex and laborious task of analyzing the large volumes of retrieved data. Recently, a rapid and reliable method for automatically identifying activation times (ATs) of SWs was presented, offering substantial efficiency gains. To extend the automated data-processing pipeline, novel automated methods are needed for partitioning identified ATs into their propagation cycles, and for visualizing the HR spatiotemporal maps. A novel cycle partitioning algorithm (termed REGROUPS) is presented. REGROUPS employs an iterative REgion GROwing procedure and incorporates a Polynomial-surface-estimate Stabilization step, after initiation by an automated seed selection process. Automated activation map visualization was achieved via an isochronal contour mapping algorithm, augmented by a heuristic 2-step scheme. All automated methods were collectively validated in a series of experimental test cases of normal and abnormal SW propagation, including instances of patchy data quality. The automated pipeline performance was highly comparable to manual analysis, and outperformed a previously proposed partitioning approach. These methods will substantially improve the efficiency of GI HR mapping research. PMID:20927594

  17. Source localization of ictal epileptic activity investigated by high resolution EEG and validated by SEEG.

    PubMed

    Koessler, Laurent; Benar, Christian; Maillard, Louis; Badier, Jean-Michel; Vignal, Jean Pierre; Bartolomei, Fabrice; Chauvel, Patrick; Gavaret, Martine

    2010-06-01

    High resolution electroencephalography (HR-EEG) combined with source localization methods has mainly been used to study interictal spikes and there have been few studies comparing source localization of scalp ictal patterns with depth EEG. To address this issue, 10 patients with four different scalp ictal patterns (ictal spikes, rhythmic activity, paroxysmal fast activity, obscured) were investigated by both HR-EEG and stereoelectroencephalography (SEEG). Sixty-four scalp-EEG sensors and a sampling rate of 1kHz were used to record scalp ictal patterns. Five different source models (moving dipole, rotating dipole, MUSIC, LORETA, and sLORETA) were used in order to perform source localization. Seven to 10 intracerebral electrodes were implanted during SEEG investigations. For each source model, the concordance between ictal source localization and epileptogenic zone defined by SEEG was assessed. Results were considered to agree if they localized in the same sublobar area as defined by a trained epileptologist. Across the study population, the best concordance between source localization methods and SEEG (9/10) was obtained with equivalent current dipole modeling. MUSIC and LORETA had a concordance of 7/10 whereas sLORETA had a concordance of only 5/10. Four of our patients classified into different groups (ictal spikes, paroxysmal fast activity, obscured) had complete concordance between source localization methods and SEEG. A high signal to noise ratio, a short time window of analysis (<1s) and bandpass filtering around the frequency of rhythmic activity allowed improvement of the source localization results. A high level of agreement between source localization methods and SEEG can be obtained for ictal spike patterns and for scalp-EEG paroxysmal fact activities whereas scalp rhythmic discharges can be accurately localized but originated from seizure propagation network. PMID:20206700

  18. ATLAS: an airborne active linescan system for high-resolution topographic mapping

    NASA Astrophysics Data System (ADS)

    Willetts, David V.; Kightley, Peter J.; Mole, S. G.; Pearson, Guy N.; Pearson, P.; Coffey, Adrian S.; Stokes, Tim J.; Tapster, Paul R.; Westwood, M.

    2004-12-01

    High resolution ground mapping is of interest for survey and management of long linear features such as roads, railways and pipelines, and for georeferencing of areas such as flood plains for hydrological purposes. ATLAS (Airborne Topographic Laser System) is an active linescan system operating at the eyesafe wavelength of 1.5μm. Built for airborne survey, it is currently certified for use on a Twin Squirrel helicopter for operation from low levels to heights above 500 feet allowing commercial survey in built up areas. The system operates at a pulse repetition frequency of 56kHz with a line completed in 15ms, giving 36 points/m2 at the surface at the design flight speed. At each point the range to the ground is measured together with the scan angle of the system. This data is combined with a system attitude measurement from an integrated inertial navigation system and with system position derived from differential GPS data aboard the platform. A recording system captures the data with a synchronised time-stamp to enable post-processed reconstruction of a cloud of data points that will give a three-dimensional representation of the terrain, allowing the points to be located with respect to absolute Earth referenced coordinates to a precision of 5cm in three axes. This paper summarises the design, harmonisation, evaluation and performance of the system, and shows examples of survey data.

  19. High-resolution seismic structure analysis of an active submarine mud volcano area off SW Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Hsiao-Shan; Hsu, Shu-Kun; Tsai, Wan-Lin; Tsai, Ching-Hui; Lin, Shin-Yi; Chen, Song-Chuen

    2015-04-01

    In order to better understand the subsurface structure related to an active mud volcano MV1 and to understand their relationship with gas hydrate/cold seep formation, we conducted deep-towed side-scan sonar (SSS), sub-bottom profiler (SBP), multibeam echo sounding (MBES), and multi-channel reflection seismic (MCS) surveys off SW Taiwan from 2009 to 2011. As shown in the high-resolution sub-bottom profiler and EK500 sonar data, the detailed structures reveal more gas seeps and gas flares in the study area. In addition, the survey profiles show several submarine landslides occurred near the thrust faults. Based on the MCS results, we can find that the MV1 is located on top of a mud diapiric structure. It indicates that the MV1 has the same source as the associated mud diapir. The blanking of the seismic signal may indicate the conduit for the upward migration of the gas (methane or CO2). Therefore, we suggest that the submarine mud volcano could be due to a deep source of mud compressed by the tectonic convergence. Fluids and argillaceous materials have thus migrated upward along structural faults and reach the seafloor. The gas-charged sediments or gas seeps in sediments thus make the seafloor instable and may trigger submarine landslides.

  20. High-Resolution Modeling to Assess Tropical Cyclone Activity in Future Climate Regimes

    SciTech Connect

    Lackmann, Gary

    2013-06-10

    Applied research is proposed with the following objectives: (i) to determine the most likely level of tropical cyclone intensity and frequency in future climate regimes, (ii) to provide a quantitative measure of uncertainty in these predictions, and (iii) to improve understanding of the linkage between tropical cyclones and the planetary-scale circulation. Current mesoscale weather forecasting models, such as the Weather Research and Forecasting (WRF) model, are capable of simulating the full intensity of tropical cyclones (TC) with realistic structures. However, in order to accurately represent both the primary and secondary circulations in these systems, model simulations must be configured with sufficient resolution to explicitly represent convection (omitting the convective parameterization scheme). Most previous numerical studies of TC activity at seasonal and longer time scales have not utilized such explicit convection (EC) model runs. Here, we propose to employ the moving nest capability of WRF to optimally represent TC activity on a seasonal scale using a downscaling approach. The statistical results of a suite of these high-resolution TC simulations will yield a realistic representation of TC intensity on a seasonal basis, while at the same time allowing analysis of the feedback that TCs exert on the larger-scale climate system. Experiments will be driven with analyzed lateral boundary conditions for several recent Atlantic seasons, spanning a range of activity levels and TC track patterns. Results of the ensemble of WRF simulations will then be compared to analyzed TC data in order to determine the extent to which this modeling setup can reproduce recent levels of TC activity. Next, the boundary conditions (sea-surface temperature, tropopause height, and thermal/moisture profiles) from the recent seasons will be altered in a manner consistent with various future GCM/RCM scenarios, but that preserves the large-scale shear and incipient disturbance

  1. High Resolution Simulations of Tearing and Flux-Rope Formation in Active Region Jets

    NASA Astrophysics Data System (ADS)

    Wyper, P. F.; DeVore, C. R.; Karpen, J. T.

    2015-12-01

    Observations of coronal jets increasingly suggest that local fragmentation and the generation of small-scale structure plays an important role in the dynamics of these events. In the magnetically closed corona, jets most often occur near active regions and are associated with an embedded-bipole topology consisting of a 3D magnetic null point atop a domed fan separatrix surface at the base of a coronal loop. Impulsive reconnection in the vicinity of the null point between the magnetic fluxes inside and outside the dome launches the jet along the loop. Wyper & Pontin 2014 showed that the 3D current layers that facilitate such reconnection are explosively unstable to tearing, generating complex flux-rope structures. Utilizing the adaptive mesh capabilities of the Adaptively Refined Magnetohydrodynamics Solver, we investigate the generation of such fine-scale structure in high-resolution simulations of active-region jets. We observe the formation of multiple flux-rope structures forming across the fan separatrix surface and discuss the photospheric signatures of these flux ropes and the associated local topology change. We also introduce a new way of identifying such flux ropes in the magnetic field, based on structures observed in the magnetic squashing factor calculated on the photosphere. By tracking the position and number of new null points produced by the fragmentation, we also show that the formation of flux ropes can occur away from the main null region on the flanks of the separatrix dome and that the jet curtain has a highly complex magnetic structure. This work was funded through an appointment to the NASA Postdoctoral Program and by NASA's Living With a Star TR&T program.

  2. High Resolution Projections of Indian Summer Monsoon Synoptic Activity in a Warming Climate

    NASA Astrophysics Data System (ADS)

    Sukumaran, Sandeep; Ravindran, Ajayamohan; Thazhe Purayil, Sabin; Veluthedathekuzhiyil, Praveen

    2016-04-01

    The cyclonic systems of varying intensity, collectively known as Low Pressure Systems (LPS) are responsible more than 50% of the precipitation over Central India. Despite its importance, the future variability of LPS is poorly understood mainly due to the inadequate representation of these systems in global climate models. Insufficient spatial resolution of the current generation coupled models is a hindrance to resolve these storms properly. In order to overcome this problem, we use the Geophysical Fluid Dynamics Laboratory's (GFDL) High Resolution Atmospheric Model (HiRAM) to simulate current and future climate, with a model grid spacing of ~50km. The time slice experiments for current (1981 - 2005) and future (2071 - 2095) climate are forced with bias-corrected SSTs from Coupled Model Inter-comparison Project (CMIP5) historical and RCP8.5 simulations respectively. Four ensembles of the experiments are conducted with SST forcing taken from four different CMIP5 models. A benchmark simulation of the HiRAM model with observed SSTs shows that the model is capable of simulating the life cycle of the observed LPS reasonably well. In addition, HiRAM realistically simulates the observed LPS track density. Further, the track density in the historical ensemble is comparable with both observations and benchmark simulation. In the RCP8.5 simulations, an overall decline in the LPS activity is seen which is found to be related to the decrease in the high intensity systems in a warming environment. Consistent with the decrease in LPS activity, the seasonal mean monsoon precipitation is also declining in RCP8.5 simulations.

  3. High resolution seismic imaging of an active normal fault in the Agri Valley, Southern Apennines, Italy

    NASA Astrophysics Data System (ADS)

    Improta, L.; Bruno, P.; di Fiore, V.; Mariani, S.

    2004-12-01

    The Agri Valley is an intermontane basin located in the Southern Apennine seismic belt (Italy) whose formation in tied to large NW-trending trastensional and extensional faults active since Early Pleistocene. Recent faulting activity in the area is documented by faulted paleosoils and suggested by a M7 earthquake that struck the basin in 1857. On the contrary, present-day background seismicity in the area is extremely low. Despite intense geomorphic investigations, the identification of the source responsible for this historical event and of further large seismogenic faults in the area is still a matter of debate. A new NW trending normal faulting system has been recently recognized based on subtle geomorphic expressions on the ridge bounding the basin westward. Recent faulting activity along this structure is locally documented by a trench. Aimed at yielding new information about the shallow structure of the fault, we conducted a high resolution seismic experiment in a small lacustrine basin, located 4 km south of the trench, in which the presence of the fault is inferred by a linear surface warping but trench excavation is impractical. Both multi-fold wide-angle data and multichannel near vertical reflection data have been collected along a 220-m-long profile in order to obtain an accurate model of the basin combining seismic velocity and reflectivity images. About 3600 first arrival traveltimes picked on 36 wide-angle record sections have been inverted by a non-linear tomographic technique that is specially designed to image complex structures. The tomographic inversion provides a high-resolution velocity model of the basin down to 60 m depth. The model is strongly heterogeneous and displays sharp lateral velocity variations. Seismic reflection processing has been applied to both data sets. Data have been edited for trace quality and first (refracted and direct) arrivals have been muted. A following FK dip filtering on the shot gathers reduced the energy

  4. Investigation of solar active regions at high resolution by balloon flights of the solar optical universal polarimeter, extended definition phase

    NASA Technical Reports Server (NTRS)

    Tarbell, Theodore D.

    1993-01-01

    Technical studies of the feasibility of balloon flights of the former Spacelab instrument, the Solar Optical Universal Polarimeter, with a modern charge-coupled device (CCD) camera, to study the structure and evolution of solar active regions at high resolution, are reviewed. In particular, different CCD cameras were used at ground-based solar observatories with the SOUP filter, to evaluate their performance and collect high resolution images. High resolution movies of the photosphere and chromosphere were successfully obtained using four different CCD cameras. Some of this data was collected in coordinated observations with the Yohkoh satellite during May-July, 1992, and they are being analyzed scientifically along with simultaneous X-ray observations.

  5. High-resolution Mapping of In Vivo Gastrointestinal Slow Wave Activity Using Flexible Printed Circuit Board Electrodes: Methodology and Validation

    PubMed Central

    DU, PENG; O'GRADY, G.; EGBUJI, J. U.; LAMMERS, W. J.; BUDGETT, D.; NIELSEN, P.; WINDSOR, J. A.; PULLAN, A. J.; CHENG, L. K.

    2014-01-01

    High-resolution, multi-electrode mapping is providing valuable new insights into the origin, propagation, and abnormalities of gastrointestinal (GI) slow wave activity. Construction of high-resolution mapping arrays has previously been a costly and time-consuming endeavor, and existing arrays are not well suited for human research as they cannot be reliably and repeatedly sterilized. The design and fabrication of a new flexible printed circuit board (PCB) multi-electrode array that is suitable for GI mapping is presented, together with its in vivo validation in a porcine model. A modified methodology for characterizing slow waves and forming spatiotemporal activation maps showing slow waves propagation is also demonstrated. The validation study found that flexible PCB electrode arrays are able to reliably record gastric slow wave activity with signal quality near that achieved by traditional epoxy resin-embedded silver electrode arrays. Flexible PCB electrode arrays provide a clinically viable alternative to previously published devices for the high-resolution mapping of GI slow wave activity. PCBs may be mass-produced at low cost, and are easily sterilized and potentially disposable, making them ideally suited to intra-operative human use. PMID:19224368

  6. Gastric activity studies using a magnetic tracer.

    PubMed

    Cordova-Fraga, T; Bernal-Alvarado, J J; Gutierrez-Juarez, G; Sosa, M; Vargas-Luna, M

    2004-10-01

    A magnetic pulse generator has been set up in order to study gastric activity. Two coils 1.05 m in diameter, arranged in a Helmholtz configuration, were used. The system generated magnetic field pulses higher than 15 mT, of duration 17.3+/-1.2 ms. Measurements were performed in 11 male volunteers, with average age 29.3+/-6.4 years and body mass index 26.0+/-4.8 kg m(-2). Magnetite (Fe3O4) particles with diameters from 75 to 125 microm were used as magnetic tracers, which were mixed in 250 ml of yogurt in concentrations from 2 to 5 g. Signals were registered by using a high speed 3 axis fluxgate digital magnetometer and processed to determine the relaxation of the magnetic tracers by fitting a first-order exponential function to the data, a mean relaxation constant K = 116+/-40 s(-1) was obtained. Also, an average gastric peristaltic frequency was measured; a value of 3.2+/-0.3 cpm was determined. PMID:15535190

  7. Using High-Resolution Forward Model Simulations of Ideal Atmospheric Tracers to Assess the Spatial Information Content of Inverse CO2 Flux Estimates

    NASA Technical Reports Server (NTRS)

    Pawson, Steven; Nielsen, J. Eric

    2011-01-01

    Attribution of observed atmospheric carbon concentrations to emissions on the country, state or city level is often inferred using "inversion" techniques. Such computations are often performed using advanced mathematical techniques, such as synthesis inversion or four-dimensional variational analysis, that invoke tracing observed atmospheric concentrations backwards through a transport model to a source region. It is, to date, not well understood how well such techniques can represent fine spatial (and temporal) structure in the inverted flux fields. This question is addressed using forward-model computations with idealized tracers emitted at the surface in a large number of grid boxes over selected regions and examining how distinctly these emitted tracers can be detected downstream. Initial results show that tracers emitted in half-degree grid boxes over a large region of the Eastern USA cannot be distinguished from each other, even at short distances over the Atlantic Ocean, when they are emitted in grid boxes separated by less than five degrees of latitude - especially when only total-column observations are available. A large number of forward model simulations, with varying meteorological conditions, are used to assess how distinctly three types observations (total column, upper tropospheric column, and surface mixing ratio) can separate emissions from different sources. Inferences inverse modeling and source attribution will be drawn.

  8. The active tropical cyclone season of 2005 2006 over Northwest Australia: Operational model performance and high resolution case studies

    NASA Astrophysics Data System (ADS)

    Buckley, B. W.; Leslie, L. M.; Leplastrier, M.; Qi, L.

    2007-08-01

    There are three main aims of this study. First, the main features of the active 2005 2006 Australian region tropical cyclone (TC) season are summarized, with particular emphasis on the northwest Australian region. Second, an assessment is made of the skill of the available operational global and regional numerical weather prediction (NWP) models for three of the most significant TCs (TCs Clare, Glenda and Hubert), each of which made landfall on the northwest coast of Australia. Third, high-resolution numerical modelling simulations of these same three TCs are described in detail. The numerical weather prediction (NWP) model used here was developed at the University of Oklahoma, and in this study it utilises initial and boundary conditions obtained from archived analyses and forecasts provided by the Australian Bureau of Meteorology, as well as a 4D-Var data assimilation scheme to ingest all available satellite data. The high-resolution numerical model is multiply two-way nested, with the innermost domain having a resolution of 5 km. It was found that unlike the operational models, which were restricted by relatively low resolution and less data, the high resolution model was able to capture most of the major features of all three TC lifecycles including development from initial tropical depressions, intensification, and their tracks, landfall, and associated rainfall and wind fields.

  9. Mapping of odor-related neuronal activity in the olfactory bulb by high-resolution 2-deoxyglucose autoradiography

    SciTech Connect

    Lancet, D.; Greer, C.A.; Kauer, J.S.; Shepherd, G.M.

    1982-01-01

    The spatial distribution of odor-induced neuronal activity in the olfactory bulb, the first relay station of the olfactory pathway, is believed to reflect important aspects of chemosensory coding. We report here the application of high-resolution 2-deoxyglucose autoradiography to the mapping of spatial patterns of metabolic activity at the level of single neurons in the olfactory bulb. It was found that glomeruli, which are synaptic complexes containing the first synaptic relay, tend to be uniformly active or inactive during odor exposure. Differential 2-deoxyglucose uptake was also observed in the somata of projection neurons (mitral cells) and interneurons (periglomerular and granule cells). This confirms and extends our previous studies in which odor-specific laminar and focal uptake patterns were revealed by the conventional x-ray film 2-deoxyglucose method due to Sokoloff and colleagues (Sokoloff, L., Reivich, M., Kennedy, C., DesRosiers, M. H., Patlak, C. S., Pettigrew, K. D., Sakurada, O. and Shinohara, M. (1977) J. Neurochem. 28, 897-916). Based on results obtained by the two methods, it is suggested that the glomerulus as a whole serves as a functional unit of activity. The high-resolution results are interpreted in terms of the well-characterized synaptic organization of the olfactory bulb and also serve to illustrate the capability of the 2-deoxyglucose autoradiographic technique to map metabolic activity in single neurons of the vertebrate central nervous system.

  10. The Track of Brain Activity during the Observation of TV Commercials with the High-Resolution EEG Technology

    PubMed Central

    Astolfi, Laura; Vecchiato, Giovanni; De Vico Fallani, Fabrizio; Salinari, Serenella; Cincotti, Febo; Aloise, Fabio; Mattia, Donatella; Marciani, Maria Grazia; Bianchi, Luigi; Soranzo, Ramon; Babiloni, Fabio

    2009-01-01

    We estimate cortical activity in normal subjects during the observation of TV commercials inserted within a movie by using high-resolution EEG techniques. The brain activity was evaluated in both time and frequency domains by solving the associate inverse problem of EEG with the use of realistic head models. In particular, we recover statistically significant information about cortical areas engaged by particular scenes inserted within the TV commercial proposed with respect to the brain activity estimated while watching a documentary. Results obtained in the population investigated suggest that the statistically significant brain activity during the observation of the TV commercial was mainly concentrated in frontoparietal cortical areas, roughly coincident with the Brodmann areas 8, 9, and 7, in the analyzed population. PMID:19584910

  11. Identification of metabolites from an active fraction of Cajanus cajan seeds by high resolution mass spectrometry.

    PubMed

    Tekale, Satishkumar S; Jaiwal, Bhimrao V; Padul, Manohar V

    2016-11-15

    Antioxidants are important food additives which prolong food storage due to their protective effects against oxidative degradation of foods by free radicals. However, the synthetic antioxidants show toxic properties. Alternative economical and eco-friendly approach is screening of plant extract for natural antioxidants. Plant phenolics are potent antioxidants. Hence, in present study Cajanus cajan seeds were analyzed for antioxidant activity, Iron chelating activity and total phenolic content. The antioxidant activity using DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay showed 71.3% inhibition and 65.8% Iron chelating activity. Total 37 compounds including some short peptides and five major abundant compounds were identified in active fraction of C. cajan seeds. This study concludes that C. cajan seeds are good source of antioxidants and Iron chelating activity. Metabolites found in C. cajan seeds which remove reactive oxygen species (ROS), may help to alleviate oxidative stress associated dreaded health problem like cancer and cardiovascular diseases. PMID:27283694

  12. Activators of photoluminescence in calcite: evidence from high-resolution, laser-excited luminescence spectroscopy

    USGS Publications Warehouse

    Pedone, V.A.; Cercone, K.R.; Burruss, R.C.

    1990-01-01

    Laser-excited luminescence spectroscopy of a red-algal, biogenic calcite and a synthetic Mn-calcite can make the distinction between organic and trace-element activators of photoluminescence. Organic-activated photoluminescence in biogenic calcite is characterized by significant peak shifts and increasing intensity with shorter-wavelength excitation and by significant decreases in intensity after heating to ??? 400??C. In contrast, Mn-activated photoluminescence shows no peak shift, greatest intensity under green excitation and limited changes after heating. Examination of samples with a high-sensitivity spectrometer using several wavelengths of exciting light is necessary for identification of photoluminescence activators. ?? 1990.

  13. High-resolution non-contact measurement of the electrical activity of plants in situ using optical recording.

    PubMed

    Zhao, Dong-Jie; Chen, Yang; Wang, Zi-Yang; Xue, Lin; Mao, Tong-Lin; Liu, Yi-Min; Wang, Zhong-Yi; Huang, Lan

    2015-01-01

    The limitations of conventional extracellular recording and intracellular recording make high-resolution multisite recording of plant bioelectrical activity in situ challenging. By combining a cooled charge-coupled device camera with a voltage-sensitive dye, we recorded the action potentials in the stem of Helianthus annuus and variation potentials at multiple sites simultaneously with high spatial resolution. The method of signal processing using coherence analysis was used to determine the synchronization of the selected signals. Our results provide direct visualization of the phloem, which is the distribution region of the electrical activities in the stem and leaf of H. annuus, and verify that the phloem is the main action potential transmission route in the stems of higher plants. Finally, the method of optical recording offers a unique opportunity to map the dynamic bioelectrical activity and provides an insight into the mechanisms of long-distance electrical signal transmission in higher plants. PMID:26333536

  14. High-resolution non-contact measurement of the electrical activity of plants in situ using optical recording

    PubMed Central

    Zhao, Dong-Jie; Chen, Yang; Wang, Zi-Yang; Xue, Lin; Mao, Tong-Lin; Liu, Yi-Min; Wang, Zhong-Yi; Huang, Lan

    2015-01-01

    The limitations of conventional extracellular recording and intracellular recording make high-resolution multisite recording of plant bioelectrical activity in situ challenging. By combining a cooled charge-coupled device camera with a voltage-sensitive dye, we recorded the action potentials in the stem of Helianthus annuus and variation potentials at multiple sites simultaneously with high spatial resolution. The method of signal processing using coherence analysis was used to determine the synchronization of the selected signals. Our results provide direct visualization of the phloem, which is the distribution region of the electrical activities in the stem and leaf of H. annuus, and verify that the phloem is the main action potential transmission route in the stems of higher plants. Finally, the method of optical recording offers a unique opportunity to map the dynamic bioelectrical activity and provides an insight into the mechanisms of long-distance electrical signal transmission in higher plants. PMID:26333536

  15. 76 FR 80891 - Small Takes of Marine Mammals Incidental to Specified Activities; Cape Wind's High Resolution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-27

    ... and their occurrence in Nantucket Sound in the notice of the proposed IHA (76 FR 56735, September 14... IHA (76 FR 56735, September 14, 2011). The activities to be conducted have not changed between the IHA... proposed IHA notice (76 FR 56735, September 14, 2011), the application, and associated documents...

  16. Investigation of solar active regions at high resolution by balloon flights of the solar optical universal polarimeter, definition phase

    NASA Technical Reports Server (NTRS)

    Tarbell, Theodore D.; Topka, Kenneth P.

    1992-01-01

    The definition phase of a scientific study of active regions on the sun by balloon flight of a former Spacelab instrument, the Solar Optical Universal Polarimeter (SOUP) is described. SOUP is an optical telescope with image stabilization, tunable filter and various cameras. After the flight phase of the program was cancelled due to budgetary problems, scientific and engineering studies relevant to future balloon experiments of this type were completed. High resolution observations of the sun were obtained using SOUP components at the Swedish Solar Observatory in the Canary Islands. These were analyzed and published in studies of solar magnetic fields and active regions. In addition, testing of low-voltage piezoelectric transducers was performed, which showed they were appropriate for use in image stabilization on a balloon.

  17. High-resolution seismic monitoring of rockslide activity in the Illgraben, Switzerland

    NASA Astrophysics Data System (ADS)

    Burtin, Arnaud; Hovius, Niels; Dietze, Michael; McArdell, Brian

    2014-05-01

    Rockfalls and rockslides are important geomorphic processes in landscape dynamics. They contribute to the evolution of slopes and supply rock materials to channels, enabling fluvial incision. Hillslope processes are also a natural hazard that we need to quantify and, if possible, predict. For these reasons, it is necessary to determine the triggering conditions and mechanisms involved in rockfalls. Rainfall is a well-known contributor since water, through soil moisture or pore pressure, may lead to the inception and propagation of cracks and can induce slope failure. Water can also affect slope stability through effects of climatic conditions such as the fluctuations of temperature around the freezing point. During the winter of 2012, we have recorded with a seismic array of 8 instruments substantial rockslide activity that affected a gully in the Illgraben catchment in the Swiss Alps. Three stations were positioned directly around the gully with a nearest distance of 400 m. The period of intense activity did not start during a rainstorm as it is common in summer but during a period of oscillation of temperatures around the freezing point. The activity did not occur in a single event but lasted about a week with a decay in time of the event frequency. Many individual events had two distinct seismic signals, with first, a short duration phase of about 10 s at frequencies below 5 Hz that we interpret as a slope failure signature, followed by a second long duration signal of > 60 s at frequencies above 10 Hz that we attribute to the propagation of rock debris down the slope. Thanks to the array of seismic sensors, we can study the fine details of this rockslide sequence by locating the different events, determining their distribution in time, and systematic quantification of seismic metrics (energy, duration, intensity...). These observations are compared to independent meteorological constrains and laser scan data to obtain an estimate of the volume mobilized by the

  18. Impact of irrigations on simulated convective activity over Central Greece: A high resolution study

    NASA Astrophysics Data System (ADS)

    Kotsopoulos, S.; Tegoulias, I.; Pytharoulis, I.; Kartsios, S.; Bampzelis, D.; Karacostas, T.

    2014-12-01

    The aim of this research is to investigate the impact of irrigations in the characteristics of convective activity simulated by the non-hydrostatic Weather Research and Forecasting model with the Advanced Research dynamic solver (WRF-ARW, version 3.5.1), under different upper air synoptic conditions in central Greece. To this end, 42 cases equally distributed under the six most frequent upper air synoptic conditions, which are associated with convective activity in the region of interest, were utilized considering two different soil moisture scenarios. In the first scenario, the model was initialized with the surface soil moisture of the ECMWF analysis data that usually does not take into account the modification of soil moisture due to agricultural activity in the area of interest. In the second scenario, the soil moisture in the upper soil layers of the study area was modified to the field capacity for the irrigated cropland. Three model domains, covering Europe, the Mediterranean Sea and northern Africa (d01), the wider area of Greece (d02) and central Greece - Thessaly region (d03) are used at horizontal grid-spacings of 15km, 5km and 1km respectively. The model numerical results indicate a strong dependence of convective spatiotemporal characteristics from the soil moisture difference between the two scenarios. Acknowledgements: This research is co-financed by the European Union (European Regional Development Fund) and Greek national funds, through the action "COOPERATION 2011: Partnerships of Production and Research Institutions in Focused Research and Technology Sectors" (contract number 11SYN_8_1088 - DAPHNE) in the framework of the operational programme "Competitiveness and Entrepreneurship" and Regions in Transition (OPC II, NSRF 2007-2013).

  19. Non-Invasive Imaging of Neuroanatomical Structures and Neural Activation with High-Resolution MRI

    PubMed Central

    Herberholz, Jens; Mishra, Subrata H.; Uma, Divya; Germann, Markus W.; Edwards, Donald H.; Potter, Kimberlee

    2011-01-01

    Several years ago, manganese-enhanced magnetic resonance imaging (MEMRI) was introduced as a new powerful tool to image active brain areas and to identify neural connections in living, non-human animals. Primarily restricted to studies in rodents and later adapted for bird species, MEMRI has recently been discovered as a useful technique for neuroimaging of invertebrate animals. Using crayfish as a model system, we highlight the advantages of MEMRI over conventional techniques for imaging of small nervous systems. MEMRI can be applied to image invertebrate nervous systems at relatively high spatial resolution, and permits identification of stimulus-evoked neural activation non-invasively. Since the selection of specific imaging parameters is critical for successful in vivo micro-imaging, we present an overview of different experimental conditions that are best suited for invertebrates. We also compare the effects of hardware and software specifications on image quality, and provide detailed descriptions of the steps necessary to prepare animals for successful imaging sessions. Careful consideration of hardware, software, experiments, and specimen preparation will promote a better understanding of this novel technique and facilitate future MEMRI studies in other laboratories. PMID:21503138

  20. Extended chromatin and DNA fibers from active plant nuclei for high-resolution FISH.

    PubMed

    Lavania, U C; Yamamoto, M; Mukai, Y

    2003-10-01

    The conventional protocol for isolation of cell wall free nuclei for release of DNA fibers for plants involves mechanical removal of the cell wall and separation of debris by sieve filtration. The mechanical grinding pressure applied during the process leaves only the more tolerant G(1) nuclei intact, and all other states of active nuclei that may be present in the target tissues (e.g., leaf) are simply crushed/disrupted during the isolation process. Here we describe an alternative enzymatic protocol for isolation of nuclei from root tip tissue. Cell wall free nuclei at a given stage of cell cycle, free of any cell debris, could be realized in suspension that are fit for preparation of extended fibers suitable for fiber FISH applications. The protocol utilizes selective harvest of active nuclei from root tip tissue in liquid suspension under the influence of cell wall-degrading enzymes, and provides opportunities to target cell cycle-specific nuclei from interphase through division phase for the release of extended DNA fibers. Availability of cell cycle-specific fibers may have added value in transcriptional analysis, DNA:RNA hybridization, visualization of DNA replication and replication forks, and improved FISH efficiency. PMID:14500692

  1. High-resolution measurement of electrically-evoked vagus nerve activity in the anesthetized dog

    NASA Astrophysics Data System (ADS)

    Yoo, Paul B.; Lubock, Nathan B.; Hincapie, Juan G.; Ruble, Stephen B.; Hamann, Jason J.; Grill, Warren M.

    2013-04-01

    Objective. Not fully understanding the type of axons activated during vagus nerve stimulation (VNS) is one of several factors that limit the clinical efficacy of VNS therapies. The main goal of this study was to characterize the electrical recruitment of both myelinated and unmyelinated fibers within the cervical vagus nerve. Approach. In anesthetized dogs, recording nerve cuff electrodes were implanted on the vagus nerve following surgical excision of the epineurium. Both the vagal electroneurogram (ENG) and laryngeal muscle activity were recorded in response to stimulation of the right vagus nerve. Main results. Desheathing the nerve significantly increased the signal-to-noise ratio of the ENG by 1.2 to 9.9 dB, depending on the nerve fiber type. Repeated VNS following nerve transection or neuromuscular block (1) enabled the characterization of A-fibers, two sub-types of B-fibers, and unmyelinated C-fibers, (2) confirmed the absence of stimulation-evoked reflex compound nerve action potentials in both the ipsilateral and contralateral vagus nerves, and (3) provided evidence of stimulus spillover into muscle tissue surrounding the stimulating electrode. Significance. Given the anatomical similarities between the canine and human vagus nerves, the results of this study provide a template for better understanding the nerve fiber recruitment patterns associated with VNS therapies.

  2. Attaining high-resolution eruptive histories for active arc volcanoes with argon geochronology

    NASA Astrophysics Data System (ADS)

    Calvert, A. T.

    2012-04-01

    Geochronology of active arc volcanoes commonly illuminates eruptive behavior over tens to hundreds of thousands of years, lengthy periods of repose punctuated by short eruptive episodes, and spatial and compositional changes with time. Despite the >1 Gyr half-life of 40K, argon geochronology is an exceptional tool for characterizing Pleistocene to Holocene eruptive histories and for placing constraints on models of eruptive behavior. Reliable 40Ar/39Ar ages of calc-alkaline arc rocks with rigorously derived errors small enough (± 500 to 3,000 years) to constrain eruptive histories are attainable using careful procedures. Sample selection and analytical work in concert with geologic mapping and stratigraphic studies are essential for determining reliable eruptive histories. Preparation, irradiation and spectrometric techniques have all been optimized to produce reliable, high-precision results. Examples of Cascade and Alaska/Aleutian eruptive histories illustrating duration of activity from single centers, eruptive episodicity, and spatial and compositional changes with time will be presented: (1) Mt. Shasta, the largest Cascade stratovolcano, has a 700,000-year history (Calvert and Christiansen, 2011 Fall AGU). A similar sized and composition volcano (Rainbow Mountain) on the Cascade axis was active 1200-950 ka. The eruptive center then jumped west 15 km to the south flank of the present Mt. Shasta and produced a stratovolcano from 700-450 ka likely rivaling today's Mt. Shasta. The NW portion of that edifice failed in an enormous (>30 km3) debris avalanche. Vents near today's active summit erupted 300-135 ka, then 60-15 ka. A voluminous, but short-lived eruptive sequence occurred at 11 ka, including a summit explosion producing a subplinian plume, followed by >60 km3 andesite-dacite Shastina domes and flows, then by the flank dacite Black Butte dome. Holocene domes and flows subsequently rebuilt the summit and flowed to the north and east. (2) Mt. Veniaminof on

  3. Photoemission from activated gallium arsenide. I. Very-high-resolution energy distribution curves

    NASA Astrophysics Data System (ADS)

    Drouhin, H.-J.; Hermann, C.; Lampel, G.

    1985-03-01

    The energy distribution curves (EDC's) of the photoelectrons emitted from the (100) face of a p-type doped (~1019 cm-3) GaAs crystal, activated to negative electron affinity in ultrahigh-vacuum conditions, is investigated. The study is performed at 300 and 120 K under well-focused Kr+-laser excitation and with a very-high-energy resolution (20 meV). The analysis of the EDC's as a function of the photon energy, mainly at low temperature, is shown to provide a very direct picture of the GaAs band structure away from the Brillouin-zone center. The experimental results are well fitted by a spherical, nonparabolic k-->.p--> perturbation calculation of the coupled conduction and valence bands, for electron kinetic energies up to 1 eV in the central Γ valley. The essential role played by the subsidiary L and X minima in the energy relaxation and photoemission processes is evidenced. The main contribution to the total emitted current is due to electrons which were thermalized in the bulk Γ minimum and have lost an average energy ~=130 meV in the band-bending region prior to emission into vacuum. The band-bending value is shown to be >=0.5 eV. The yield and time evolution of GaAs photocathodes are discussed. This detailed study leads to a reexamination of the pioneer work of L. W. James and J. L. Moll [Phys. Rev. 183, 740 (1969)] and to a good understanding of the photoemission properties of activated GaAs.

  4. A new active array MST radar system with enhanced capabilities for high resolution atmospheric observations

    NASA Astrophysics Data System (ADS)

    Durga rao, Meka; Jayaraman, Achuthan; Patra, Amit; Venkat Ratnam, Madineni; Narayana Rao, T.; Kamaraj, Pandian; Jayaraj, Katta; Kmv, Prasad; Kamal Kumar, J.; Raghavendra, J.; Prasad, T. Rajendra; Thriveni, A.; Yasodha, Polisetti

    2016-07-01

    A new version of the 53-MHz MST Radar, using the 1024 solid state Transmit-Receive Modules (TRM), necessary feeder network, multi-channel receiver and a modified radar controller has been established using the existing antenna array of 1024 crossed Yagis. The new system has been configured for steering the beam on a pulse-to-pulse basis in all 360o azimuth and 20o zenith angle, providing enhanced capability to study the Mesosphere-Stratosphere-Troposphere and Ionosphere. The multi channel receiver system has been designed for Spaced Antenna (SA) and Interferometry/ Iamging applications. The new system has also been configured for radiating in circular polarization for its application in the Ionosphere Incoherent Scatter mode. The new active array MST radar at Very-High-Frequency (53-MHz) located at Gadanki (13.45°N, 79.18°E), a tropical station in India, will be used to enhance the observations of winds, turbulence during the passage of convective events over the radar site as deep convection occurs very often at tropical latitudes. The new configuration with enhanced average power, beam agility with multi-channel experiments will be a potential source for studying middle atmosphere and ionosphere. In this paper, we present the system configuration, new capabilities and the first results obtained using the new version of the MST Radar.

  5. Mapping of active faults based on the analysis of high-resolution seismic reflection profiles in offshore Montenegro

    NASA Astrophysics Data System (ADS)

    Vucic, Ljiljana; Glavatovic, Branislav

    2014-05-01

    High-resolution seismic-reflection data analysis is considered as important tool for mapping of active tectonic faults, since seismic exploration methods on varied scales can image subsurface structures of different depth ranges. Mapping of active faults for the offshore area of Montenegro is performed in Petrel software, using reflection database consist of 2D profiles in length of about 3.500 kilometers and 311 square kilometers of 3D seismics, acquired from 1979 to 2003. Montenegro offshore area is influenced by recent tectonic activity with numerous faults, folded faults and over trusts. Based on reflection profiles analysis, the trust fault system offshore Montenegro is reveled, parallel to the coast and extending up to 15 kilometers from the offshore line. Then, the system of normal top carbonate fault planes is mapped and characterized on the southern Adriatic, with NE trending. The tectonic interpretation of the seismic reflection profiles in Montenegro point toward the existence of principally reverse tectonic forms in the carbonate sediments, covered by young Quaternary sandy sediments of thickness 1-3 kilometers. Also, reflective seismic data indicate the active uplifting of evaporite dome on about 10 kilometers of coastline.

  6. High-resolution digital movies of emerging flux and horizontal flows in active regions on the sun

    NASA Technical Reports Server (NTRS)

    Topka, K.; Ferguson, S.; Frank, Z.; Tarbell, T.; Title, A.

    1988-01-01

    High-resolution observations of active regions in many wavelength bands obtained at the Vacuum Tower Telescope of NSO/Sunspot (Sacramento Peak) are presented. The SOUP tunable filter, HRSO 1024 x 1024 CCD camera, and a sunspot tracker for image stabilization were used. Subarrays of 512 x 512 pixels were processed digitally and recorded on videodisk in movie format. The movies with 0.5 to 1 arcsecond resolution of the following simultaneous observations were shown: green continuum, longitudinal magnetogram, Doppler velocity, Fe I 5576 A line center, H alpha wings, and H alpha line center. The best set of movies show a 90 x 90 arcsecond field-of-view of an active region at S29, W11. When viewed at speeds of a few thousand times real-time, the photospheric movies clearly show the active region fields being distorted by a remarkable combination of systematic flows and small eruptions of new flux. Flux emergence is most easily discovered in line center movies: an elongated dark feature appears first, followed soon after by bright points at one or both ends. A brief, strong upflow is seen when the dark feature first appears; downflow in the bright points persists much longer. The magnetic flux appears to increase gradually over this extended period. Some of the flux emergence events were studied in detail, with measurements of horizontal and vertical velocities and magnetic flux versus time within one footpoint of the loop.

  7. High-resolution water column survey to identify active sublacustrine hydrothermal discharge zones within Lake Rotomahana, North Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Walker, Sharon L.; de Ronde, Cornel E. J.; Fornari, Daniel; Tivey, Maurice A.; Stucker, Valerie K.

    2016-03-01

    Autonomous underwater vehicles were used to conduct a high-resolution water column survey of Lake Rotomahana using temperature, pH, turbidity, and oxidation-reduction potential (ORP) to identify active hydrothermal discharge zones within the lake. Five areas with active sublacustrine venting were identified: (1) the area of the historic Pink Terraces; (2) adjacent to the western shoreline subaerial "Steaming Cliffs," boiling springs and geyser; (3) along the northern shoreline to the east of the Pink Terrace site; (4) the newly discovered Patiti hydrothermal system along the south margin of the 1886 Tarawera eruption rift zone; and (5) a location in the east basin (northeast of Patiti Island). The Pink Terrace hydrothermal system was active prior to the 1886 eruption of Mount Tarawera, but venting along the western shoreline, in the east basin, and the Patiti hydrothermal system appear to have been initiated in the aftermath of the eruption, similar to Waimangu Valley to the southwest. Different combinations of turbidity, pH anomalies (both positive and negative), and ORP responses suggest vent fluid compositions vary over short distances within the lake. The seasonal period of stratification limits vertical transport of heat to the surface layer and the hypolimnion temperature of Lake Rotomahana consequently increases with an average warming rate of ~ 0.010 °C/day due to both convective hydrothermal discharge and conductive geothermal heating. A sudden temperature increase occurred during our 2011 survey and was likely the response to an earthquake swarm just 11 days prior.

  8. Application of active contours for photochromic tracer flow extraction.

    PubMed

    Androutsos, D; Trahanias, P E; Venetsanopoulos, A N

    1997-06-01

    This paper addresses the implementation of image processing and computer vision techniques to automate tracer flow extraction in images obtained by the photochromic dye technique. This task is important in modeled arterial blood flow studies. Currently, it is performed via manual application of B-spline curve fitting. However, this is a tedious and error-prone procedure and its results are nonreproducible. In the proposed approach, active contours, snakes, are employed in a new curve-fitting method for tracer flow extraction in photochromic images. An algorithm implementing snakes is introduced to automate extraction. Utilizing correlation matching, the algorithm quickly locates and localizes all flow traces in the images. The feasibility of the method for tracer flow extraction is demonstrated. Moreover, results regarding the automation algorithm are presented showing its accuracy and effectiveness. The proposed approach for tracer flow extraction has potential for real-system application. PMID:9184890

  9. Offshore active faults of the Mikata fault zone in Fukui, Japan, revealed by high-resolution seismic profiles

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Sugiyama, Y.; Sakamoto, I.; Takino, Y.; Murakami, F.; Hosoya, T.; Usami, T.

    2014-12-01

    The Mikata fault zone are located in coastal and shallow sea area off Fukui Prefecture, West Japan. National Institute of Advanced Industrial Science and Technology (AIST) and Tokai University conducted, as part of MEXT 2013 nearshore active fault survey project, a high-resolution multi-channel seismic survey using Boomer and a 12-channel streamer cable, acoustic profiling survey using parametric sub-bottom profiler and shallow-sea offshore drilling, in order to clarify distribution and activity of the Mikata fault zone. The seismic reflection surveys identified four reflection surfaces as vertical displacement markers in the post-glacial deposits at a depth ranging from ca. 4.5m to ca. 17m below the sea bottom on the downthrown side. We estimated the age of each marker reflection surface by using the C14 age and others from 4m-long core obtained on the downthrown side of fault and the sea level change in the latest Pleistocene and early Holocene around Japan. The results of these surveys have revealed that the fault system was reactivated three times since the latest Pleistocene. The vertical slip rate and average recurrence interval of the fault system are estimated at ca. 0.8-1.0 m/ky and 2,000-3,800 years, respectively.

  10. Probing the Active Site of Candida Glabrata Dihydrofolate Reductase with High Resolution Crystal Structures and the Synthesis of New Inhibitors

    SciTech Connect

    Liu, J.; Bolstad, D; Smith, A; Priestley, N; Wright, D; Anderson, A

    2009-01-01

    Candida glabrata, a fungal strain resistant to many commonly administered antifungal agents, has become an emerging threat to human health. In previous work, we validated that the essential enzyme, dihydrofolate reductase, is a drug target in C. glabrata. Using a crystal structure of dihydrofolate reductase from C. glabrata bound to an initial lead compound, we designed a class of biphenyl antifolates that potently and selectively inhibit both the enzyme and the growth of the fungal culture. In this work, we explore the structure-activity relationships of this class of antifolates with four new high resolution crystal structures of enzyme:inhibitor complexes and the synthesis of four new inhibitors. The designed inhibitors are intended to probe key hydrophobic pockets visible in the crystal structure. The crystal structures and an evaluation of the new compounds reveal that methyl groups at the meta and para positions of the distal phenyl ring achieve the greatest number of interactions with the pathogenic enzyme and the greatest degree of selectivity over the human enzyme. Additionally, antifungal activity can be tuned with substitution patterns at the propargyl and para-phenyl positions.

  11. Late Quaternary high resolution sequence stratigraphy of an active rift, the Sperchios Basin, Greece: An analogue for subtle stratigraphic plays

    SciTech Connect

    Eliet, P.P.; Gawthorpe, R.L.

    1996-12-31

    The Sperchios Basin is an active asymmetric graben, bounded to the south by a major border fault system with major fault segments typically 20-30 km long. The basin is dominated by a major axial fluvio-deltaic system which enters the partially enclosed Maliakos Gulf to the east. Lateral sourced depositional systems within the basin comprise hanging-wall and footwall-derived alluvial fans and a narrow coastal plain along the footwall scarp bordering the Maliakos Gulf. High resolution seismic data from the Maliakos Gulf reveals three late Quaternary progradational parasequences sourced from axial and lateral depositional systems, with a regional late-Pleistocene transgressive surface dated at circa. 10 ka BP within the Maliakos Gulf. Differential subsidence of the late Pleistocene transgressive surface indicates marked variation in subsidence from 2.4 m ka{sup -1} at fault segment centers to 0.8 m ka{sup -1} at segment boundaries. The geometry and internal variability of each parasequence is controlled by the interplay of the local accommodation development and fluctuations in sediment supply and climatic conditions. The Sperchios Rift provides a modem analogue for subtle stratigraphic plays within ancient extensional basins. The study of controls on sediment source and transport patterns within active rifts has refined our appreciation of the controls on potential reservoir distribution and geometries.

  12. Late Quaternary high resolution sequence stratigraphy of an active rift, the Sperchios Basin, Greece: An analogue for subtle stratigraphic plays

    SciTech Connect

    Eliet, P.P. ); Gawthorpe, R.L. )

    1996-01-01

    The Sperchios Basin is an active asymmetric graben, bounded to the south by a major border fault system with major fault segments typically 20-30 km long. The basin is dominated by a major axial fluvio-deltaic system which enters the partially enclosed Maliakos Gulf to the east. Lateral sourced depositional systems within the basin comprise hanging-wall and footwall-derived alluvial fans and a narrow coastal plain along the footwall scarp bordering the Maliakos Gulf. High resolution seismic data from the Maliakos Gulf reveals three late Quaternary progradational parasequences sourced from axial and lateral depositional systems, with a regional late-Pleistocene transgressive surface dated at circa. 10 ka BP within the Maliakos Gulf. Differential subsidence of the late Pleistocene transgressive surface indicates marked variation in subsidence from 2.4 m ka[sup -1] at fault segment centers to 0.8 m ka[sup -1] at segment boundaries. The geometry and internal variability of each parasequence is controlled by the interplay of the local accommodation development and fluctuations in sediment supply and climatic conditions. The Sperchios Rift provides a modem analogue for subtle stratigraphic plays within ancient extensional basins. The study of controls on sediment source and transport patterns within active rifts has refined our appreciation of the controls on potential reservoir distribution and geometries.

  13. A High Resolution, Unobscured View of the Active Regions in (Ultra) Luminous Infrared Galaxies from a VLA 33 GHz Survey

    NASA Astrophysics Data System (ADS)

    Barcos-Muñoz, L.; Leroy, A.; Evans, A.; et al.

    2016-06-01

    I will present a new survey of 33 GHz radio continuum emission from local U/LIRGs carried out using the Karl G. Jansky Very Large Array (VLA). This is the first such survey and it combines high resolution, good sensitivity, and multi-configuration observations that should have sensitivity to emission on all spatial scales. (Ultra) luminous infrared galaxies host some of the most extreme star-forming environments in the local universe, with large reservoirs of molecular gas and dust concentrated in the central few kpc. Our VLA observations allow us to see through the dust in these systems to resolve the sizes of their active regions, which is essential to understand the surface and volume densities of star formation and gas in these extreme systems. I will present the best size measurements to date of the active regions for our 22 targets. I will show what these sizes imply about gas volume and surface density and infrared luminosity surface densities. I will also lay out the physical implications of these values for the strength of star formation and feedback (especially radiative feedback) in extreme environments.

  14. High-resolution topographic change detection of an active earthflow using airborne and terrestrial LiDAR, Mill Gulch, California

    NASA Astrophysics Data System (ADS)

    Murphy, B. P.; DeLong, S.

    2011-12-01

    In landscapes where airborne laser swath mapping (ALSM) exists, terrestrial laser scanning (TLS) can be used to update high-resolution topographic models for quantification of landscape change. At Mill Gulch in northern California, we scanned an active earthflow using TLS in 2011 that had also been imaged by ALSM in 2003 and 2007. In order to evaluate change at the sub-meter level between the ALSM and TLS data, we generated a custom, 30 cm resolution ALSM digital elevation model (DEM), employed geographic transformations to align the disparate datasets, and refined the vertical alignment using an unaltered road surface. We then conducted vegetation removal from the TLS data, gridded it to 30 cm, and produced detailed maps of topographic evolution. Previous work comparing the 2003 and 2007 ALSM data indicated that this earthflow translated blocks of material as much as 5 m/yr and that significant material was removed by the channel at the toe of the earthflow, leading to a net elevation decrease across the earthflow. Over the last four years, the earthflow has experienced overall rotational movement leading to distinct failure planes in the source area with elevations decreasing as much as 3.75 m, while the toe aggraded up to 2.5 m. Maximum translation rates in the transport zone have decreased to 3.5 m/yr and very little material was removed by the channel. Early analysis indicates a slight increase in the net volume of the earthflow and an average elevation increase of 0.05 m between 2007 and 2011. It is possible this is the result of any number of factors, including the failure of TLS to adequately measure the thalweg depth of supra-flow gullies and depths of tension fractures, higher sensitivity to grasses in TLS data, decreased material density (and concomitant volumetric increase) due to tension fracturing, the swelling of clays and increased pore water pressure in the earthflow. However, it is also reasonable that this result reflects minor systematic error

  15. Continuous, Large-Scale Processing of Seismic Archives for High-Resolution Monitoring of Seismic Activity and Seismogenic Properties

    NASA Astrophysics Data System (ADS)

    Waldhauser, F.; Schaff, D. P.

    2012-12-01

    Archives of digital seismic data recorded by seismometer networks around the world have grown tremendously over the last several decades helped by the deployment of seismic stations and their continued operation within the framework of monitoring earthquake activity and verification of the Nuclear Test-Ban Treaty. We show results from our continuing effort in developing efficient waveform cross-correlation and double-difference analysis methods for the large-scale processing of regional and global seismic archives to improve existing earthquake parameter estimates, detect seismic events with magnitudes below current detection thresholds, and improve real-time monitoring procedures. We demonstrate the performance of these algorithms as applied to the 28-year long seismic archive of the Northern California Seismic Network. The tools enable the computation of periodic updates of a high-resolution earthquake catalog of currently over 500,000 earthquakes using simultaneous double-difference inversions, achieving up to three orders of magnitude resolution improvement over existing hypocenter locations. This catalog, together with associated metadata, form the underlying relational database for a real-time double-difference scheme, DDRT, which rapidly computes high-precision correlation times and hypocenter locations of new events with respect to the background archive (http://ddrt.ldeo.columbia.edu). The DDRT system facilitates near-real-time seismicity analysis, including the ability to search at an unprecedented resolution for spatio-temporal changes in seismogenic properties. In areas with continuously recording stations, we show that a detector built around a scaled cross-correlation function can lower the detection threshold by one magnitude unit compared to the STA/LTA based detector employed at the network. This leads to increased event density, which in turn pushes the resolution capability of our location algorithms. On a global scale, we are currently building

  16. Tectonic expression of an active slab tear from high-resolution seismic and bathymetric data offshore Sicily (Ionian Sea)

    NASA Astrophysics Data System (ADS)

    Gutscher, Marc-André; Dominguez, Stephane; Lepinay, Bernard Mercier; Pinheiro, Luis; Gallais, Flora; Babonneau, Nathalie; Cattaneo, Antonio; Le Faou, Yann; Barreca, Giovanni; Micallef, Aaron; Rovere, Marzia

    2016-01-01

    Subduction of a narrow slab of oceanic lithosphere beneath a tightly curved orogenic arc requires the presence of at least one lithospheric scale tear fault. While the Calabrian subduction beneath southern Italy is considered to be the type example of this geodynamic setting, the geometry, kinematics and surface expression of the associated lateral, slab tear fault offshore eastern Sicily remain controversial. Results from a new marine geophysical survey conducted in the Ionian Sea, using high-resolution bathymetry and seismic profiling reveal active faulting at the seafloor within a 140 km long, two-branched fault system near Alfeo Seamount. The previously unidentified 60 km long NW trending North Alfeo Fault system shows primarily strike-slip kinematics as indicated by the morphology and steep-dipping transpressional and transtensional faults. Available earthquake focal mechanisms indicate dextral strike-slip motion along this fault segment. The 80 km long SSE trending South Alfeo fault system is expressed by one or two steeply dipping normal faults, bounding the western side of a 500+ m thick, 5 km wide, elongate, syntectonic Plio-Quaternary sedimentary basin. Both branches of the fault system are mechanically capable of generating magnitude 6-7 earthquakes like those that struck eastern Sicily in 1169, 1542, and 1693.

  17. Mesoscale activity in the Comoros Basin from satellite altimetry and a high-resolution ocean circulation model

    NASA Astrophysics Data System (ADS)

    Collins, C.; Hermes, J. C.; Reason, C. J. C.

    2014-08-01

    Recently it has been shown that anticyclonic eddies are generated in the Comoros Basin contesting the long-held notion of a single large anticyclonic cell, the Comoros Gyre. Limited knowledge exists about the mesoscale activity within the basin, a potential key source of variability for the Mozambique Channel and subsequently the Agulhas Current. In this paper an automated eddy tracking scheme, applied to satellite altimetry data and a high-resolution model simulation, is used to determine the characteristics of the anticyclonic eddies generated in the Comoros Basin. The generation and characteristics of cyclonic eddies are also investigated. The eddy tracking scheme revealed that anticyclonic eddies are primarily generated west of the tip of Madagascar due to barotropic instabilities whereas cyclonic eddies are mainly generated along the northwest coast of Madagascar as a result of baroclinic instabilities. Anticyclonic eddies, with a mean lifespan of about 3 months, reside in the basin for half their lifespan before propagating into the Mozambique Channel. On the other hand, the majority of cyclonic eddies, with a similar mean lifespan, dissipate within the basin. Initially, the anticyclones, with translation speeds of 6-8 km d-1 and mean radii of 80-100 km, follow the trajectory of the North East Madagascar Current and turn south upon reaching the African coast. The cyclonic eddies tend to be smaller (˜60 km) and have slower translation speeds (2.5-3.5 km d-1) than their anticyclonic counterparts.

  18. Impact of human activities on the geomagnetic field of Antarctica: a high resolution aeromagnetic survey over Mario Zucchelli Station.

    PubMed

    Armadillo, E; Bozzo, E; Gambetta, M; Rizzello, D

    2012-10-15

    Environmental protection of Antarctica is a fundamental principle of the Antarctic Treaty. Impact assessment and significance evaluation are due for every human activity on the remote continent. While chemical and biological contaminations are widely studied, very little is known about the electromagnetic pollution levels. In this frame, we have evaluated the significance of the impact of Mario Zucchelli Antarctic Station (Northern Victoria Land) on the local geomagnetic field. We have flown a high resolution aeromagnetic survey in drape mode at 320m over the Station, covering an area of 2km(2). The regional and the local field have been separated by a third order polynomial fitting. After the identification of the anthropic magnetic anomaly due to the Station, we have estimated the magnetic field at the ground level by downward continuation with an original inversion scheme regularized by a minimum gradient support functional to avoid high frequency noise effects. The resulting anthropic static magnetic field at ground extends up to 650m far from the Station and reaches a maximum peak to peak value of about 2800nT. This anthropic magnetic anomaly may interact with biological systems, raising the necessity to evaluate the significance of the static magnetic impact of human installations in order to protect the electromagnetic environment and the biota of Antarctica. PMID:22706521

  19. Xanthine oxidoreductase activity assay in tissues using stable isotope-labeled substrate and liquid chromatography high-resolution mass spectrometry.

    PubMed

    Murase, Takayo; Nampei, Mai; Oka, Mitsuru; Ashizawa, Naoki; Matsumoto, Koji; Miyachi, Atsushi; Nakamura, Takashi

    2016-01-01

    Studies of pathological mechanisms and XOR inhibitor characterization, such as allopurinol, febuxostat, and topiroxostat, require accurate and sensitive measurements of XOR activity. However, the established assays have some disadvantages such as susceptibility to endogenous substances such as uric acid (UA), xanthine, or hypoxanthine. Here, we aimed to develop a novel XOR activity assay utilizing a combination of high-performance liquid chromatography (LC) and high-resolution mass spectrometry (HRMS) for tissues such as the liver, kidney, and plasma. Stable isotope-labeled [(15)N2]-xanthine was utilized as substrate and the production of [(15)N2]-uric acid was determined. [(15)N2]-UA production by XOR was dependent on the amounts of [(15)N2]-xanthine and enzyme and the time of reaction. Because high concentrations of endogenous xanthine and hypoxanthine affect XOR activities, we employed a multi-component analysis using LC/HRMS to improve the accuracy of XOR activity assay. Quantification of [(15)N2]-UA was validated and showed good linearity, accuracy, and precision. We measured the XOR activities of retired ICR mice using [(15)N2]-xanthine and LC/MS. The XOR activities in plasma, kidney, and liver samples were 38.1±0.7, 158±5, 928±25pmol/min/mg of protein, respectively (mean±SD, n=5). Furthermore, we measured the XOR activities in the same samples using the LC/ultraviolet and LC/fluorescence (FL) methods. The level of [(15)N2]-xanthine oxidation by XOR was equal to that of xanthine oxidation and approximately 7.9-8.9 times higher than that of pterin oxidation. We found a good correlation between XOR activities examined using LC/MS assay with [(15)N2]-xanthine and those examined using LC/FL assay with pterin. This result suggested that although both the LC/MS assay with [(15)N2]-xanthine and the LC/FL assay with pterin were useful, the former provided information regarding XOR activities that more directly reflected the physiological condition than the latter

  20. Contribution of high resolution PLEIADES imagery to active faults analysis. Case study of the Longriba Fault System, eastern Tibet.

    NASA Astrophysics Data System (ADS)

    Ansberque, Claire; Bellier, Olivier; Godard, Vincent; Lasserre, Cécile; Wang, Mingming; Xu, Xiwei; Tan, Xibin

    2015-04-01

    High resolution imagery has largely developed during those two last decades allowing the possibility to observe and quantify geological and geomorphological features ranging from meter to few centimeters. Active tectonic and geomorphological studies have greatly benefited from the systematic use of such data. For that reason, we tested the contribution of PLEAIDES images to the analysis of an active strike-slip fault system in eastern Tibet. We used 50 cm resolution panchromatic PLEIADES images in order to map active fault segmentation, localize offsets of geomorphic markers and quantify vertical and horizontal displacements. We propose a preliminary study using PLEIADES images along the Longriba Fault System (LFS). The LFS, located at the eastern Tibetan Plateau margin, is constituted of two NW-SE dextral strike-slip and parallel fault zones: Longriqu and Maoergai, 80 and 120 km-long, respectively. It accommodates ~4 mm/yr dextral slip and very few vertical motion. We used stereo-pairs to build relative Digital Elevation Models (DEMs) (without ground control points) with a horizontal resolution ranging from 2 to 5 m, in order to understand the geometry of the system. We measured fault segments with lengths ranging from a hundred meters to several kilometers which are relatively close from each others, and several offsets of geomorphic markers (alluvial fans, ridges, rivers) ranging from a few meters to ~40 m. According to the segmentation deduced from those results we suggest that the fault has a high seismic potential (>Mw7.0) and that probably many surface rupturing earthquakes occurred along the LFS over the Holocene.

  1. Carbon cycle dynamics and solar activity embedded in a high-resolution 14C speleothem record from Belize, Central America

    NASA Astrophysics Data System (ADS)

    Lechleitner, Franziska A.; Breitenbach, Sebastian F. M.; McIntyre, Cameron; Asmerom, Yemane; Prufer, Keith M.; Polyak, Victor; Culleton, Brendan J.; Kennett, Douglas J.; Eglinton, Timothy I.; Baldini, James U. L.

    2015-04-01

    Speleothem 14C has recently emerged as a potentially powerful proxy for climate reconstruction. Several studies have highlighted the link between karst hydrology and speleothem 14C content, and a number of possible causes for this relationship have been proposed, such as dripwater flow dynamics in the karst and changes in soil organic matter (SOM) turnover time (e.g. Griffiths et al., 2012). Here we present a high resolution 14C record for a stalagmite (YOK-I) from Yok Balum cave in southern Belize, Central America. YOK-I grew continuously over the last 2000 years, and has been dated very precisely with the U-Th method (40 dates, mean uncertainty < 10 years). The excellent chronological control for this stalagmite allows us to calculate 14C activity (a14C) at the time of speleothem deposition (a14Cinit), as well as the dead carbon fraction (DCF), predominantly a measure of the reservoir effect introduced by limestone dissolution in the karst (Genty et al., 2001). Both records show striking similarities to atmospheric a14C (IntCal13) and reconstructions of solar activity and 14C production rate. We infer close coupling between cave environment and atmosphere, with minimal signal dampening, an observation supported by monitoring data (Ridley et al., in press). DCF fluctuates between approximately 10% and 16% over the entire record, with distinctly lower DCF values and higher a14Cinit during a period of reduced rainfall between ca. 700-1100 AD (linked to the Classic Maya Collapse). This behavior is consistent with observations made elsewhere, and suggests that DCF responds to karst hydrological variability, specifically open-closed system transitions. YOK-I a14Cinit typically lags atmospheric values by 10-100 cal years. A shorter lag appears to be linked to periods of drought, suggesting a response of SOM dynamics above the cave to rainfall reduction. Specifically, drought is inferred to lead to reduced bioproductivity and soil carbon turnover, lowering contributions

  2. Characterization of active fault scarps from medium to high resolution DEM: case studies from Central and Southern Apennines (Italy)

    NASA Astrophysics Data System (ADS)

    Brunori, C.; Cinti, F. R.; Ventura, G.

    2013-12-01

    We identify geo-morphometric features of active fault scarps in Italy through a semiautomatic processing using GIS. Medium to high resolution DEM was used to characterize the geometry, structural, and erosive elements of two seismogenic normal faults in Central and Southern Apennines. The Pettino fault in L'Aquila area was detected using a 1 m pixel DEM derived from airborne LiDAR survey (Friuli Venezia Giulia Civil Protection). For the Castrovillari fault in northern Calabria region was used a 4 m pixel DEM (Regional Cartography Office of Regione Calabria). Scarp segments are region of planar discontinuities identified by selected values of DEM-derived Terrain Ruggedness Index (TRI) and Vector Ruggedness Measure (VRM). These planar discontinuities corresponds to landscape features such as, river terraces, roads scarps, and other natural or human features. The discrimination between these features have been accomplished overlaying extracted features on aerial photograph, geological and geomorphologic maps and in situ survey. After that, we perform the quantitative and statistical analysis of these areas identified as "fault scarps". The identification of elements relative to the scarps (e.g. base, crest, slope) is then obtained to derive the estimate of parameters describing the fault: altitude, height of the scarp, length, slope and aspect, Terrain Ruggedness Index (TRI) and Vector Ruggedness Measure (VRM). The spatial distribution of the extracted values was obtained through their statistical analysis. We analyze scarp parameters variations along the whole scarp extent, such as strike value from aspect variations, slope and profile curvature differences as indicators of tectonic and/or erosion activity. The combined analysis of the DEM-derived parameters allows us to (a) define aspects of three-dimensional scarp geometry, (b) decipher its geomorphological significance, and (c) estimate the long-term slip rate.

  3. Internal structure of Erebus volcano, Antarctica imaged by high-resolution active-source seismic tomography and coda interferometry

    NASA Astrophysics Data System (ADS)

    Zandomeneghi, D.; Aster, R.; Kyle, P.; Barclay, A.; Chaput, J.; Knox, H.

    2013-03-01

    Erebus volcano, Antarctica has hosted a persistent convecting phonolite lava lake for over 40 years. The lake produces small (VEI 0-1) Strombolian eruptions resulting from gas slugs rising through the upper conduit system. High-resolution (to scale lengths of several hundreds of meters) three-dimensional P-wave tomographic velocity images were obtained to a depth of approximately 600 m below the volcano surface. Data were collected using 91 seismographs deployed over an approximately 4 by 4 km area of the summit region. Seismic illumination was provided by 12 chemical shots emplaced in shallow snow and ice boreholes. P-wave direct arrival travel-time measurements were used to invert for strong velocity anomalies (with spatial variations in Vp exceeding ±1 km/s) associated with the uppermost few km. Shallow anomalies correlate with fumarolic ice caves, a prominent radial chilled dike, and ring structures associated with the caldera rim. Conduit structures feeding the lava lake and other vents within the Inner Crater are evidently too small (e.g., less than many 10 s of meters) to be imaged under the resolution limits of this experiment. However, combined velocity and coda interferometry scattering intensity images identify near-summit regions with both low velocity and high scattering that are candidates for magma accommodation. Results indicate a nonaxisymmetric near-summit magmatic system that is likely constrained by heterogeneous structures in the uppermost volcano. The most extensive volume of near-summit magma likely resides approximately 500 m NW of the active Inner Crater vents at depths of 500 m and more below the surface.

  4. Non-linear responsivity characterisation of a CMOS Active Pixel Sensor for high resolution imaging of the Jovian system

    NASA Astrophysics Data System (ADS)

    Soman, M.; Stefanov, K.; Weatherill, D.; Holland, A.; Gow, J.; Leese, M.

    2015-02-01

    The Jovian system is the subject of study for the Jupiter Icy Moon Explorer (JUICE), an ESA mission which is planned to launch in 2022. The scientific payload is designed for both characterisation of the magnetosphere and radiation environment local to the spacecraft, as well as remote characterisation of Jupiter and its satellites. A key instrument on JUICE is the high resolution and wide angle camera, JANUS, whose main science goals include detailed characterisation and study phases of three of the Galilean satellites, Ganymede, Callisto and Europa, as well as studies of other moons, the ring system, and irregular satellites. The CIS115 is a CMOS Active Pixel Sensor from e2v technologies selected for the JANUS camera. It is fabricated using 0.18 μ m CMOS imaging sensor process, with an imaging area of 2000 × 1504 pixels, each 7 μ m square. A 4T pixel architecture allows for efficient correlated double sampling, improving the readout noise to better than 8 electrons rms, whilst the sensor is operated in a rolling shutter mode, sampling at up to 10 Mpixel/s at each of the four parallel outputs.A primary parameter to characterise for an imaging device is the relationship that converts the sensor's voltage output back to the corresponding number of electrons that were detected in a pixel, known as the Charge to Voltage Factor (CVF). In modern CMOS sensors with small feature sizes, the CVF is known to be non-linear with signal level, therefore a signal-dependent measurement of the CIS115's CVF has been undertaken and is presented here. The CVF is well modelled as a quadratic function leading to a measurement of the maximum charge handling capacity of the CIS115 to be 3.4 × 104 electrons. If the CIS115's response is assumed linear, its CVF is 21.1 electrons per mV (1/47.5 μ V per electron).

  5. Last Glacial - Present Glacial Activity in East Greenland Fjords Inferred from Swath Bathymetry and High-Resolution Seismic Data

    NASA Astrophysics Data System (ADS)

    Forwick, M.; Laberg, J. S.; Husum, K.; Olsen, I. L.

    2014-12-01

    Swath bathymetry and high-resolution penetration echo sounder (chirp) data from fjords and sounds between Kong Oscars Fjord and Bredefjord, East Greenland, reveal glacial landforms and sedimentary processes that can be used to infer glacial activity from the last glacial to the present. Relatively straight, linear features oriented parallel to the fjord axes, as well as beyond the mouths of some fjords, are interpreted to be glacial lineations providing evidence of fast-flowing grounded ice draining the eastern parts of the Greenland Ice Sheet during the last glacial. In some areas, the glacial lineations are the only preserved glacigenic landfjorms (e.g. beyond the mouth of Bredefjord). However, in other areas, they are covered with multiple transverse ridges interpreted to be small terminal moraines (e.g. in Youngsund). Whereas the absence of such moraines is suggested to represent a rapid ice retreat due to lift-up and disintegration during parts of the deglaciation, their presence reflects that multiple halts and/or re-advances interrupted the retreat. Acoustically stratified sediment sequences dominate the fjord-fill stratigraphies (up to 180 ms two-way travel time). These deposits are suggested to reflect repeatedly changing lithological compositions in a glacimarine environment where deposition mainly occurred from suspension fall-out, in addition to ice rafting from icebergs calving off from tidewater glaciers, and sea ice. The stratified deposits form often relatively uniform drapes indicating that the tidewater glaciers were mainly located near the fjord heads since the last deglaciation. However, acoustically transparent bodies with irregular geometries, intercalated within the stratified deposits, occur in some of the inner fjords. These are suggested to be glacigenic sediment wedges (debris-flow lobes) that formed during relatively recent advances of tidewater glaciers (e.g. in Nordfjord and Moskusoksefjord).

  6. Ultra-high Resolution Mapping of the Inner Crater of the Active Kick'em Jenny Volcano

    NASA Astrophysics Data System (ADS)

    Hart, L.; Scott, C.; Tominaga, M.; Smart, C.; Vaughn, I.; Roman, C.; Carey, S.; German, C. R.; Participants, T.

    2015-12-01

    We conducted high-resolution geological characterization of a 0.015km^2 region of the inner crater of the most active submarine volcano in the Caribbean, Kick'em Jenny, located 8 km off Grenada in the Lesser Antilles Island Arc. We obtained digital still images and microbathymetery at an altitude of 3 m from the seafloor by using stereo cameras and a BlueView system mounted on Remotely Operated Vehicle (ROV) Hercules during the NA054 cruise on E/V Nautilus (Sept. - Oct. 2014). The seafloor images were processed to construct 2-D photo mosaics of the survey area using Standard Hercules Imaging Suite. We systematically classified the photographed seafloor geology based on the distribution of seafloor morphology and the observable rock fragment and outcrop sizes. The center of the crater floor shows a smooth, coherent texture with little variation in sea floor morphology. From immediately outside this area toward the crater rim, we observe an extensive area covered with outcrops, small rocks, and sediment: and within this area, (1) the north section is partially covered by uneven outcrops with elongated lineaments and a course, rugged seafloor with individual rock fragments observable; (2) the middle section contains high variability and heterogeneity in seafloor morphology in a non-systematic manner; and (3) overall, the southern most section displays subdued seafloor features both in space and variability compared to the other areas. The distributions of rock fragments were classified into four distinct sizes. We observe: (i) little variation in size distribution near the center of the crater floor; and (ii) rock fragment size increasing toward the rim of the crater. To obtain a better understanding of the link between variation in seafloor morphology, rock size distribution, and other in situ processes, we compare our observations on the digital photo mosaic to bathymetry data and ROV visuals (e.g. vents and bacterial mats).

  7. Active faulting in the Inner California Borderlands: new constraints from high-resolution multichannel seismic and multibeam bathymetric data.

    NASA Astrophysics Data System (ADS)

    Bormann, J. M.; Holmes, J. J.; Sahakian, V. J.; Klotsko, S.; Kent, G.; Driscoll, N. W.; Harding, A. J.; Wesnousky, S. G.

    2014-12-01

    Geodetic data indicate that faults offshore of Southern California accommodate 6-8 mm/yr of dextral Pacific-North American relative plate motion. In the Inner California Borderlands (ICB), modern strike-slip deformation is overprinted on topography formed during plate boundary reorganization 30-15 Ma. Despite its proximity to urban Southern California, the hazard posed by active faults in the ICB remains poorly understood. We acquired a 4000-line-km regional grid of high-resolution, 2D multichannel seismic (MCS) reflection data and multibeam bathymetry to examine the fault architecture and tectonic evolution of the ICB. We interpret the MCS data using a sequence stratigraphic approach to establish a chronostratigraphy and identify discrete episodes of deformation. We present our results in a regional fault model that distinguishes active deformation from older structures. Significant differences exist between our model of ICB deformation and existing models. Mounting evidence suggests a westward temporal migration of slip between faults in the ICB. In the eastern ICB, slip on the Newport-Inglewood/Rose Canyon fault and the neighboring Coronado Bank fault (CBF) diminishes to the north and appears to decrease over time. Undeformed Late Pliocene sediments overlie the northern extent of the CBF and the breakaway zone of the purported Oceanside Blind Thrust. Therefore, CBF slip rate estimates based on linkage with the Palos Verdes fault to the north are unwarranted. Deformation along the San Mateo, San Onofre, and Carlsbad trends is best explained as localized deformation resulting from geometrical complexities in a dextral strike-slip fault system. In the western ICB, the San Diego Trough fault (SDTF) offsets young sediments between the US/Mexico border and the eastern margin of Avalon Knoll, where the fault is spatially coincident with the San Pedro Basin fault (SPBF). Farther west, the San Clemente fault (SCF) has a strong linear bathymetric expression. The length

  8. High Resolution Doppler Imager

    NASA Technical Reports Server (NTRS)

    Hays, Paul B.

    1999-01-01

    This report summarizes the accomplishments of the High Resolution Doppler Imager (HRDI) on UARS spacecraft during the period 4/l/96 - 3/31/99. During this period, HRDI operation, data processing, and data analysis continued, and there was a high level of vitality in the HRDI project. The HRDI has been collecting data from the stratosphere, mesosphere, and lower thermosphere since instrument activation on October 1, 1991. The HRDI team has stressed three areas since operations commenced: 1) operation of the instrument in a manner which maximizes the quality and versatility of the collected data; 2) algorithm development and validation to produce a high-quality data product; and 3) scientific studies, primarily of the dynamics of the middle atmosphere. There has been no significant degradation in the HRDI instrument since operations began nearly 8 years ago. HRDI operations are fairly routine, although we have continued to look for ways to improve the quality of the scientific product, either by improving existing modes, or by designing new ones. The HRDI instrument has been programmed to collect data for new scientific studies, such as measurements of fluorescence from plants, measuring cloud top heights, and lower atmosphere H2O.

  9. A high-resolution lake sediment record of glacier activity from SE Greenland defines abrupt Holocene cooling events

    NASA Astrophysics Data System (ADS)

    Balascio, N. L.; Bradley, R. S.; D'Andrea, W. J.

    2013-12-01

    warming. Excursions from this trend occur at c. 8.5 ka and 8.3 ka showing brief periods of readvance that are likely associated with freshwater inputs to the North Atlantic Ocean related to the ';8.2 kyr Event.' The interval from 7.7-4.1 ka is clearly defined by high organic content (>20%) and extremely low magnetic susceptibility values, which we interpret as a lack of glacial input and the complete disappearance of the glaciers in the catchment. From 4.1-1.3 ka indicators of glacial input show a step-wise pattern with significant increases in glacial activity at 4.1 ka, 3.1 ka, 1.4 ka, and 1.3 ka indicating a progressive cooling and regrowth of the glaciers. Over the last 1.3 ka, glacial input was more constant, sedimentation rates were higher (0.8 mm/yr), and the sediment is finely laminated. Analysis of the μ-XRF data shows that the laminations were deposited annually, providing a high-resolution record of changes in glacial activity over the last 1.3 ka that corresponds well with regional temperature reconstructions.

  10. Investigating Cenozoic climate change in tectonically active regions with a high-resolution atmospheric general circulation model (ECHAM5)

    NASA Astrophysics Data System (ADS)

    Mutz, Sebastian; Ehlers, Todd; Li, Jingmin; Werner, Martin; Stepanek, Christian; Lohmann, Gerrit

    2016-04-01

    Studies of Cenozoic palaeo-climates contribute to our understanding of contemporary climate change by providing insight into analogues such as the Pliocene (PLIO), and by evaluation of GCM (General Circulation Models) performance using the Mid-Holocene (MH) and the Last Glacial Maximum (LGM). Furthermore, climate is a factor to be considered in the evolution of ecology, landscapes and mountains, and in the reconstruction of erosion histories. In this study, we use high-resolution (T159) ECHAM5 simulations to investigate pre-industrial (PI) and the the above mentioned palaeo-climates for four tectonically active regions: Alaska (St. Elias Range), the US Northwest Pacific (Cascade Range), western South America (Andes) and parts of Asia (Himalaya-Tibet). The PI climate simulation is an AMIP (Atmospheric Model Intercomparison Project) style ECHAM5 experiment, whereas MH and LGM simulation are based on simulations conducted at the Alfred Wegner Institute, Bremerhaven. Sea surface boundary conditions for MH were taken from coupled atmosphere-ocean model simulations (Wei and Lohmann, 2012; Zhang et al, 2013) and sea surface temperatures and sea ice concentration for the LGM are based on GLAMAP project reconstructions (Schäfer-Neth and Paul, 2003). Boundary conditions for the PLIO simulation are taken from the PRISM (Pliocene Research, Interpretation and Synoptic Mapping) project and the employed PLIO vegetation boundary condition is created by means of the transfer procedure for the PRISM vegetation reconstruction to the JSBACH plant functional types as described by Stepanek and Lohmann (2012). For each of the investigated areas and time slices, the regional simulated climates are described by means of cluster analyses based on the variability of precipitation, 2m air temperature and the intra-annual amplitude of the values. Results indicate the largest differences to a PI climate are observed for LGM and PLIO climates in the form of widespread cooling and warming

  11. Curvature-induced activation of a passive tracer in an active bath

    NASA Astrophysics Data System (ADS)

    Mallory, S. A.; Valeriani, C.; Cacciuto, A.

    2014-09-01

    We use numerical simulations to study the motion of a large asymmetric tracer immersed in a low-density suspension of self-propelled particles in two dimensions. Specifically, we analyze how the curvature of the tracer affects its translational and rotational motion in an active environment. We find that even very small amounts of curvature are sufficient for the active bath to impart directed motion to the tracer, which results in its effective activation. We propose simple scaling arguments to characterize this induced activity in terms of the curvature of the tracer and the strength of the self-propelling force. Our results suggest new ways of controlling the transport properties of passive tracers in an active medium by carefully tailoring their geometry.

  12. Curvature-induced activation of a passive tracer in an active bath.

    PubMed

    Mallory, S A; Valeriani, C; Cacciuto, A

    2014-09-01

    We use numerical simulations to study the motion of a large asymmetric tracer immersed in a low-density suspension of self-propelled particles in two dimensions. Specifically, we analyze how the curvature of the tracer affects its translational and rotational motion in an active environment. We find that even very small amounts of curvature are sufficient for the active bath to impart directed motion to the tracer, which results in its effective activation. We propose simple scaling arguments to characterize this induced activity in terms of the curvature of the tracer and the strength of the self-propelling force. Our results suggest new ways of controlling the transport properties of passive tracers in an active medium by carefully tailoring their geometry. PMID:25314448

  13. iMUSH: The design of the Mount St. Helens high-resolution active source seismic experiment

    NASA Astrophysics Data System (ADS)

    Kiser, Eric; Levander, Alan; Harder, Steve; Abers, Geoff; Creager, Ken; Vidale, John; Moran, Seth; Malone, Steve

    2013-04-01

    calculating Fréchet kernels with dynamic ray tracing. An initial observation from these kernels is that waves traveling across the largest offsets of the experiment (~150km) have sensitivity below depths of 30km. This means that we may be able to image the magmatic system down to the Moho, estimated at ~40 km. Additional work is focusing on searching for the shot locations that provide high resolution around very shallow features beneath Mount St. Helens, such as the first magmatic reservoir at about 3 km depth, and the associated Mount St. Helens seismic zone. One way in which we are guiding this search is to find the shot locations that maximize sensitivity values within the regions of interest after summing Fréchet kernels from each shot/station pair

  14. Using Topographic Derivatives of High Resolution Data on Earth and Mars to Determine Active Processes on Mars.

    NASA Astrophysics Data System (ADS)

    Conway, S. J.; Balme, M. R.; Grindrod, P. M.

    2012-04-01

    One of the severest problems in the field of martian geomorphology is that of convergence of form (i.e., that dissimilar processes can produce similar looking landforms). Since the discovery of recently formed km-scale gullies [1] on the martian surface, debate has raged about whether these features formed by dry mass wasting, fluidisation by CO2 gas, debris flow, unconcentrated water/brine flow, or by other, exotic processes. This is an important distinction, because if these gullies are found to be formed by water, which is currently unstable at the martian surface, then a mechanism has to be found to produce this water, and this has ramifications for our understanding of martian climate and hydrology. We approach this problem by studying newly available high resolution (~ 1 m/pix) elevation models derived from stereo HiRISE (High Resolution Science Imaging Experiment) image pairs and comparing them to LiDAR datasets of analogous features on Earth. We have used hydrological topographic indices such as slope-area [e.g., 2], contributing area distribution [3] and the downslope index [4] to characterise slopes with known processes on Earth. We characterised slopes dominated by rockfall, debris flow and fluvial erosion. We then apply these same analysis techniques to gullied slopes on Mars and find that these slopes have a signal of both debris flow and fluvial processes. This suggests that Mars' recent climate has recently been more amenable to the existence of liquid water than has previously been assumed.

  15. High-resolution echocardiography

    NASA Technical Reports Server (NTRS)

    Nathan, R.

    1979-01-01

    High resolution computer aided ultrasound system provides two-and three-dimensional images of beating heart from many angles. System provides means for determining whether small blood vessels around the heart are blocked or if heart wall is moving normally without interference of dead and noncontracting muscle tissue.

  16. High-resolution headlamp

    NASA Astrophysics Data System (ADS)

    Gut, Carsten; Cristea, Iulia; Neumann, Cornelius

    2016-04-01

    The following article shall describe how human vision by night can be influenced. At first, front lighting systems that are already available on the market will be described, followed by their analysis with respect to the positive effects on traffic safety. Furthermore, how traffic safety by night can be increased since the introduction of high resolution headlamps shall be discussed.

  17. Comparing vertical profiles of natural tracers in the Williston Basin to estimate the onset of deep aquifer activation

    NASA Astrophysics Data System (ADS)

    Hendry, M. Jim; Harrington, Glenn A.

    2014-08-01

    Comparing high-resolution depth profiles of different naturally occurring environmental tracers in aquitards should yield consistent and perhaps complementary information about solute transport mechanisms and the timing of major hydrogeological and climatological events. This study evaluated whether deep, continuous profiles of aquitard pore water chloride concentration could provide further insight into the paleohydrology of the Williston Basin, Canada, than possible using high-resolution depth profiles of stable H/O isotopes of water (δ18O, δ2H). Pore water samples were obtained from extracts of cores taken over 392 m of the thick Cretaceous shale aquitard. Water samples were also collected from wells installed in the underlying regional sandy aquifer (Mannville Group; 93 m thick) and from seepage inflows into potash mine shafts (to 825 m below ground). Numerical modeling of the 1-D vertical Cl- profile supported diffusion dominated solute transport in the shales. The modeling also showed a similar time frame for development of the Cl- profile prior to activation of the aquifer as determined from the δ18O profile (20-25 Ma); however, it provided a significantly longer and potentially better-constrained time frame for evolution of the profile during the activation phase of the aquifer (0.5-1 Ma). The dominant paleoevent reflected in present-day profiles of both tracers is the introduction of glaciogenic meteoric water to the Mannville aquifer underlying the shale during the Pleistocene. The source area of this water remains to be determined.

  18. High resolution data acquisition

    DOEpatents

    Thornton, Glenn W.; Fuller, Kenneth R.

    1993-01-01

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock (38) pulse train (37) and analog circuitry (44) for generating a triangular wave (46) synchronously with the pulse train (37). The triangular wave (46) has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter (18, 32) forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter (26) counts the clock pulse train (37) during the interval to form a gross event interval time. A computer (52) then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  19. High resolution data acquisition

    DOEpatents

    Thornton, G.W.; Fuller, K.R.

    1993-04-06

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock, pulse train, and analog circuitry for generating a triangular wave synchronously with the pulse train (as seen in diagram on patent). The triangular wave has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter counts the clock pulse train during the interval to form a gross event interval time. A computer then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  20. Ultra high resolution tomography

    SciTech Connect

    Haddad, W.S.

    1994-11-15

    Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

  1. High-Resolution Autoradiography

    NASA Technical Reports Server (NTRS)

    Towe, George C; Gomberg, Henry J; Freemen, J W

    1955-01-01

    This investigation was made to adapt wet-process autoradiography to metallurgical samples to obtain high resolution of segregated radioactive elements in microstructures. Results are confined to development of the technique, which was perfected to a resolution of less than 10 microns. The radioactive samples included carbon-14 carburized iron and steel, nickel-63 electroplated samples, a powder product containing nickel-63, and tungsten-185 in N-155 alloy.

  2. High-Resolution Crystal Structures of Villin Headpiece nad Mutants with Reduced F-Actin Binding Activity

    SciTech Connect

    Meng,J.; Vardar, D.; Wang, Y.; Guo, H.; Head, J.; McKnight, C.

    2005-01-01

    Villin-type headpiece domains are approximately 70 amino acid modular motifs found at the C terminus of a variety of actin cytoskeleton-associated proteins. The headpiece domain of villin, a protein found in the actin bundles of the brush border epithelium, is of interest both as a compact F-actin binding domain and as a model folded protein. We have determined the high-resolution crystal structures of chicken villin headpiece (HP67) at 1.4 Angstrom resolution as well as two mutants, R37A and W64Y, at 1.45 and 1.5 Angstrom resolution, respectively. Replacement of R37 causes a 5-fold reduction in F-actin binding affinity in sedimentation assays. Replacement of W64 results in a much more drastic reduction in F-actin binding affinity without significant changes in headpiece structure or stability. The detailed comparison of these crystal structures with each other and to our previously determined NMR structures of HP67 and the 35-residue autonomously folding subdomain in villin headpiece, HP35, provides the details of the headpiece fold and further defines the F-actin binding site of villin-type headpiece domains.

  3. High-resolution bathymetry reveals contrasting landslide activity shaping the walls of the Mid-Atlantic Ridge axial valley

    NASA Astrophysics Data System (ADS)

    Cannat, Mathilde; Mangeney, Anne; OndréAs, HéLèNe; Fouquet, Yves; Normand, Alain

    2013-04-01

    Axial valleys are found along most slow-spreading mid-ocean ridges and are one of the most prominent topographic features on Earth. In this paper, we present the first deep-tow swath bathymetry for the axial valley walls of the Mid-Atlantic Ridge. These data allow us to analyze axial valley wall morphology with a very high resolution (0.5 to 1 m compared to ≥ 50 m for shipboard multibeam bathymetry), revealing the role played by landslides. Slow-spreading ridge axial valleys also commonly expose mantle-derived serpentinized peridotites in the footwalls of large offset normal faults (detachments). In our map of the Ashadze area (lat. 13°N), ultramafic outcrops have an average slope of 18° and behave as sliding deformable rock masses, with little fragmentation. By contrast, the basaltic seafloor in the Krasnov area (lat. 16°38'N) has an average slope of 32° and the erosion of the steep basaltic rock faces leads to extensive fragmentation, forming debris with morphologies consistent with noncohesive granular flow. Comparison with laboratory experiments suggests that the repose angle for this basaltic debris is > 25°. We discuss the interplay between the normal faults that bound the axial valley and the observed mass wasting processes. We propose that, along axial valley walls where serpentinized peridotites are exposed by detachment faults, mass wasting results in average slopes ≤ 20°, even in places where the emergence angle of the detachment is larger.

  4. High resolution infrared measurements

    NASA Technical Reports Server (NTRS)

    Kessler, B.; Cawley, Robert

    1990-01-01

    Sample ground based cloud radiance data from a high resolution infrared sensor are shown and the sensor characteristics are presented in detail. The purpose of the Infrared Analysis Measurement and Modeling Program (IRAMMP) is to establish a deterministic radiometric data base of cloud, sea, and littoral terrain clutter to be used to advance the design and development of Infrared Search and Track (IRST) systems as well as other infrared devices. The sensor is a dual band radiometric sensor and its description, together with that of the Data Acquisition System (DAS), are given. A schematic diagram of the sensor optics is shown.

  5. High-resolution HDX-MS reveals distinct mechanisms of RNA recognition and activation by RIG-I and MDA5

    PubMed Central

    Zheng, Jie; Yong, Hui Yee; Panutdaporn, Nantika; Liu, Chuanfa; Tang, Kai; Luo, Dahai

    2015-01-01

    RIG-I and MDA5 are the major intracellular immune receptors that recognize viral RNA species and undergo a series of conformational transitions leading to the activation of the interferon-mediated antiviral response. However, to date, full-length RLRs have resisted crystallographic efforts and a molecular description of their activation pathways remains hypothetical. Here we employ hydrogen/deuterium exchange coupled with mass spectrometry (HDX-MS) to probe the apo states of RIG-I and MDA5 and to dissect the molecular details with respect to distinct RNA species recognition, ATP binding and hydrolysis and CARDs activation. We show that human RIG-I maintains an auto-inhibited resting state owing to the intra-molecular HEL2i-CARD2 interactions while apo MDA5 lacks the analogous intra-molecular interactions and therefore adopts an extended conformation. Our work demonstrates that RIG-I binds and responds differently to short triphosphorylated RNA and long duplex RNA and that sequential addition of RNA and ATP triggers specific allosteric effects leading to RIG-I CARDs activation. We also present a high-resolution protein surface mapping technique that refines the cooperative oligomerization model of neighboring MDA5 molecules on long duplex RNA. Taken together, our data provide a high-resolution view of RLR activation in solution and offer new evidence for the molecular mechanism of RLR activation. PMID:25539915

  6. "High resolution seismic imaging of an active fault in the eastern Guadalquivir Basin (Betic Cordillera, Southern Spain)"

    NASA Astrophysics Data System (ADS)

    Serrano, Inmaculada; Torcal, Federico; Martín, José Benito

    2015-10-01

    We calculated the high resolution seismic velocity, Poisson's ratio, crack density and saturation ratio structures in and around the source areas of the Torreperogil seismic series (October 2012-April 2013). This seismic series, characterized by a large number of low magnitude (below Mw 3.7 or Md 3.9) and very shallow microearthquakes, took place in the Guadalquivir Basin, a large flexural foreland basin with a linear ENE-WSW trending bounded to the north by the Iberian Massif and to the south by the Betic Cordillera and filled from a middle Miocene to Plio-Quaternary sedimentary sequence. In the upper layers of the crust, strong low-velocity anomalies are extensively distributed under the central zone, which together with high Poisson's ratio and crack density values may correspond to rocks which are less likely to fracture, perhaps due to the accumulation of tectonic and seismic stress. 93% of the earthquakes occurred at depths of up to 8 km, which could indicate that the base of the seismogenic zone lies at this depth. The seismic series was concentrated in layers of strong structural heterogeneities (in the boundary area between low and high anomalies), which were likely to generate earthquakes due to differential strain accumulation beneath the region. The high velocity areas are also considered to be strong yet brittle parts of the fault zone, which may generate earthquakes (at depths of between 5 km and 9 km). By contrast, low velocity areas are less prone to fracture, allowing seismic slippage to take place (from 2 to 4 km depth). The best estimate of the depth of the main shock (mbLg 3.9) is 7.6 km, which could tend to nucleate at the base of the seismogenic zone, at the "fault end" on the boundary between a low velocity zone to the east and a high velocity zone to the west, indicating the fault plane which separates both areas laterally. Assuming that this seismic contrast is one of the main Torreperogil faults it could imply that stress has accumulated

  7. A high-resolution peak fractionation approach for streamlined screening of nuclear-factor-E2-related factor-2 activators in Salvia miltiorrhiza.

    PubMed

    Zhang, Hui; Luo, Li-Ping; Song, Hui-Peng; Hao, Hai-Ping; Zhou, Ping; Qi, Lian-Wen; Li, Ping; Chen, Jun

    2014-01-24

    Generation of a high-purity fraction library for efficiently screening active compounds from natural products is challenging because of their chemical diversity and complex matrices. In this work, a strategy combining high-resolution peak fractionation (HRPF) with a cell-based assay was proposed for target screening of bioactive constituents from natural products. In this approach, peak fractionation was conducted under chromatographic conditions optimized for high-resolution separation of the natural product extract. The HRPF approach was automatically performed according to the predefinition of certain peaks based on their retention times from a reference chromatographic profile. The corresponding HRPF database was collected with a parallel mass spectrometer to ensure purity and characterize the structures of compounds in the various fractions. Using this approach, a set of 75 peak fractions on the microgram scale was generated from 4mg of the extract of Salvia miltiorrhiza. After screening by an ARE-luciferase reporter gene assay, 20 diterpene quinones were selected and identified, and 16 of these compounds were reported to possess novel Nrf2 activation activity. Compared with conventional fixed-time interval fractionation, the HRPF approach could significantly improve the efficiency of bioactive compound discovery and facilitate the uncovering of minor active components. PMID:24406141

  8. High resolution Doppler lidar

    NASA Technical Reports Server (NTRS)

    Abreu, Vincent J.; Hays, Paul B.; Barnes, John E.

    1989-01-01

    A high resolution lidar system was implemented to measure winds in the lower atmosphere. The wind speed along the line of sight was determined by measuring the Doppler shift of the aerosol backscattered laser signal. The system in its present configuration is stable, and behaves as indicated by theoretical simulations. This system was built to demonstrate the capabilities of the detector system as a prototype for a spaceborne lidar. The detector system investigated consisted of a plane Fabry-Perot etalon, and a 12-ring anode detector. This system is generically similar to the Fabry-Perot interferometer developed for passive wind measurements on board the Dynamics Explorer satellite. That this detector system performs well in a lidar configuration was demonstrated.

  9. Very high resolution radiometer

    NASA Technical Reports Server (NTRS)

    Aronson, A. I.

    1974-01-01

    A primary sensor used in environmental and earth-resource observation, the Very High Resolution Radiometer (VHRR) was designed for use on the ITOS D series spacecraft. The VHRR provides a 0.47 mile resolution made possible with a mercury-cadmium-telluride detector cooled to approximately 105 K by a passive radiator cooler. The components of this system are described. The optical subsystem of the VHRR consists of a scanning mirror, a Dall-Kirkham telescope, a dichroic beam splitter, relay lenses, spectral filters, and an IR detector. Signal electronics amplify and condition the signals from the infrared and visible light detector. Sync generator electronics provides the necessary time signals. Scan-drive electronics is used for commutation of the motor winding, velocity, and phase control. A table lists the performance parameters of the VHRR.

  10. High resolution ultrasonic densitometer

    SciTech Connect

    Dress, W.B.

    1983-01-01

    The velocity of torsional stress pulses in an ultrasonic waveguide of non-circular cross section is affected by the temperature and density of the surrounding medium. Measurement of the transit times of acoustic echoes from the ends of a sensor section are interpreted as level, density, and temperature of the fluid environment surrounding that section. This paper examines methods of making these measurements to obtain high resolution, temperature-corrected absolute and relative density and level determinations of the fluid. Possible applications include on-line process monitoring, a hand-held density probe for battery charge state indication, and precise inventory control for such diverse fluids as uranium salt solutions in accountability storage and gasoline in service station storage tanks.

  11. Predictability of Indian summer monsoon weather during active and break phases using a high resolution regional model

    NASA Astrophysics Data System (ADS)

    Taraphdar, S.; Mukhopadhyay, P.; Goswami, B. N.

    2010-11-01

    As the active and break phases of Indian monsoon are associated with different large scale background regimes, the predictability of monsoon weather is expected to be different during these phases. In the present study, an ensemble of ‘identical twin’ perturbation experiments are carried out using Weather Research Forecast model at 15 km resolution to demonstrate the predictability of weather during these phases. The initial conditions are taken from the 9 years (2001-2009) control simulations during periods of strong intra-seasonal oscillations events. The study revealed that the background estimates are different in these two contrasting regimes with more errors in the active phases confined mostly along the monsoon trough region. As a consequence, the predictability of active (break) period is found to be around 4 (10) days. Thus, the rapid (sluggish) error growth indicates that the monsoon weather such as lows are less (more) predictable during active (break) phases.

  12. Fine-structural distribution of MMP-2 and MMP-9 activities in the rat skeletal muscle upon training: a study by high-resolution in situ zymography.

    PubMed

    Yeghiazaryan, Marine; Żybura-Broda, Katarzyna; Cabaj, Anna; Włodarczyk, Jakub; Sławińska, Urszula; Rylski, Marcin; Wilczyński, Grzegorz M

    2012-07-01

    Matrix metalloproteinases (MMPs) are key regulators of extracellular matrix remodeling, but have also important intracellular targets. The purpose of this study was to examine the activity and subcellular localization of the gelatinases MMP-2 and MMP-9 in skeletal muscle of control and physically trained rats. In control hind limb muscle, the activity of the gelatinases was barely detectable. In contrast, after 5 days of intense exercise, in Soleus (Sol), but not Extensor digitorum longus (EDL) muscle, significant upregulation of gelatinolytic activity in myofibers was observed mainly in the nuclei, as assessed by high resolution in situ zymography. The nuclei of quiescent satellite cells did not contain the activity. Within the myonuclei, the gelatinolytic activity colocalized with an activated RNA Polymerase II. Also in Sol, but not in EDL, there were few foci of mononuclear cells with strongly positive cytoplasm, associated with apparent necrotic myofibers. These cells were identified as activated satellite cells/myoblasts. No extracellular gelatinase activity was observed. Gel zymography combined with subcellular fractionation revealed training-related upregulation of active MMP-2 in the nuclear fraction, and increase of active MMP-9 in the cytoplasmic fraction of Sol. Using RT-PCR, selective increase in MMP-9 mRNA was observed. We conclude that training activates nuclear MMP-2, and increases expression and activity of cytoplasmic MMP-9 in Sol, but not in EDL. Our results suggest that the gelatinases are involved in muscle adaptation to training, and that MMP-2 may play a novel role in myonuclear functions. PMID:22419075

  13. High Resolution Laboratory Spectroscopy

    NASA Astrophysics Data System (ADS)

    Brünken, S.; Schlemmer, S.

    2016-05-01

    In this short review we will highlight some of the recent advancements in the field of high-resolution laboratory spectroscopy that meet the needs dictated by the advent of highly sensitive and broadband telescopes like ALMA and SOFIA. Among these is the development of broadband techniques for the study of complex organic molecules, like fast scanning conventional absorption spectroscopy based on multiplier chains, chirped pulse instrumentation, or the use of synchrotron facilities. Of similar importance is the extension of the accessible frequency range to THz frequencies, where many light hydrides have their ground state rotational transitions. Another key experimental challenge is the production of sufficiently high number densities of refractory and transient species in the laboratory, where discharges have proven to be efficient sources that can also be coupled to molecular jets. For ionic molecular species sensitive action spectroscopic schemes have recently been developed to overcome some of the limitations of conventional absorption spectroscopy. Throughout this review examples demonstrating the strong interplay between laboratory and observational studies will be given.

  14. Characterization of Hydraulic Active Fractures in a Dolostone Aquifer Using Heat and Contaminants As Tracers

    NASA Astrophysics Data System (ADS)

    Maldaner, C. H.; Coleman, T. I.; Parker, B. L.; Cherry, J. A.

    2014-12-01

    The number of hydraulically active fractures serving as advective contaminant migration pathways facilitating plume migration in fractured rock aquifers cannot be determined with confidence from indirect means such as visual inspection of core, borehole geophysics, and is only inferred from hydraulic tests. However, the position of depth-discrete hydraulic activity may be determined using contaminants or heat as tracers yet spatially detailed profile measurement techniques are required without imparting measurement bias of an open borehole. Contaminant concentration profiles from numerous samples along continuous core from a site contaminated since the early 1980's and heat injection in the sealed boreholes with high resolution profile monitoring are used to characterize the fracture network . Heat pulse tests using active distributed temperature sensing (DTS) were conducted in coreholes sealed with an impermeable flexible liner manufactured by FLUTe (Santa Fe, NM) to detect hydraulically active fracture zones. Using a Silixa ULTIMA-HSTM DTS, temperature data was acquired every 12.6 cm along an optic fiber cable with a spatial resolution of 29 cm. Temperature precision is on the order of 0.02°C for averaged measurements collected over 5 minute intervals. The test consisted of heating the measurement cable for 4 hours and monitoring the cooling process for over 8 hours. The resulting dataset consists of high-resolution temperature profiles at five-minute time steps during the test period. Dolostone rock composes most of the lithology units of the corehole, therefore it is unlikely that there are significant variations in rock thermal diffusivity. Multiple, successive temperature profiles were used to identify depth-discrete, hydraulically active flow zones with varying transmissivity based on different rates of heat dissipation. These variations were then compared with independent datasets including detected concentrations of contaminants in numerous rock core

  15. Empirical electro-optical and x-ray performance evaluation of CMOS active pixels sensor for low dose, high resolution x-ray medical imaging.

    PubMed

    Arvanitis, C D; Bohndiek, S E; Royle, G; Blue, A; Liang, H X; Clark, A; Prydderch, M; Turchetta, R; Speller, R

    2007-12-01

    Monolithic complementary metal oxide semiconductor (CMOS) active pixel sensors with high performance have gained attention in the last few years in many scientific and space applications. In order to evaluate the increasing capabilities of this technology, in particular where low dose high resolution x-ray medical imaging is required, critical electro-optical and physical x-ray performance evaluation was determined. The electro-optical performance includes read noise, full well capacity, interacting quantum efficiency, and pixels cross talk. The x-ray performance, including x-ray sensitivity, modulation transfer function, noise power spectrum, and detection quantum efficiency, has been evaluated in the mammographic energy range. The sensor is a 525 x 525 standard three transistor CMOS active pixel sensor array with more than 75% fill factor and 25 x 25 microm pixel pitch. Reading at 10 f/s, it is found that the sensor has 114 electrons total additive noise, 10(5) electrons full well capacity with shot noise limited operation, and 34% interacting quantum efficiency at 530 nm. Two different structured CsI:Tl phosphors with thickness 95 and 115 microm, respectively, have been optically coupled via a fiber optic plate to the array resulting in two different system configurations. The sensitivity of the two different system configurations was 43 and 47 electrons per x-ray incident on the sensor. The MTF at 10% of the two different system configurations was 9.5 and 9 cycles/mm with detective quantum efficiency of 0.45 and 0.48, respectively, close to zero frequency at approximately 0.44 microC/kg (1.72 mR) detector entrance exposure. The detector was quantum limited at low spatial frequencies and its performance was comparable with high resolution a: Si and charge coupled device based x-ray imagers. The detector also demonstrates almost an order of magnitude lower noise than active matrix flat panel imagers. The results suggest that CMOS active pixel sensors when coupled

  16. Empirical electro-optical and x-ray performance evaluation of CMOS active pixels sensor for low dose, high resolution x-ray medical imaging

    SciTech Connect

    Arvanitis, C. D.; Bohndiek, S. E.; Royle, G.; Blue, A.; Liang, H. X.; Clark, A.; Prydderch, M.; Turchetta, R.; Speller, R.

    2007-12-15

    Monolithic complementary metal oxide semiconductor (CMOS) active pixel sensors with high performance have gained attention in the last few years in many scientific and space applications. In order to evaluate the increasing capabilities of this technology, in particular where low dose high resolution x-ray medical imaging is required, critical electro-optical and physical x-ray performance evaluation was determined. The electro-optical performance includes read noise, full well capacity, interacting quantum efficiency, and pixels cross talk. The x-ray performance, including x-ray sensitivity, modulation transfer function, noise power spectrum, and detection quantum efficiency, has been evaluated in the mammographic energy range. The sensor is a 525x525 standard three transistor CMOS active pixel sensor array with more than 75% fill factor and 25x25 {mu}m pixel pitch. Reading at 10 f/s, it is found that the sensor has 114 electrons total additive noise, 10{sup 5} electrons full well capacity with shot noise limited operation, and 34% interacting quantum efficiency at 530 nm. Two different structured CsI:Tl phosphors with thickness 95 and 115 {mu}m, respectively, have been optically coupled via a fiber optic plate to the array resulting in two different system configurations. The sensitivity of the two different system configurations was 43 and 47 electrons per x-ray incident on the sensor. The MTF at 10% of the two different system configurations was 9.5 and 9 cycles/mm with detective quantum efficiency of 0.45 and 0.48, respectively, close to zero frequency at {approx}0.44 {mu}C/kg (1.72 mR) detector entrance exposure. The detector was quantum limited at low spatial frequencies and its performance was comparable with high resolution a:Si and charge coupled device based x-ray imagers. The detector also demonstrates almost an order of magnitude lower noise than active matrix flat panel imagers. The results suggest that CMOS active pixel sensors when coupled to

  17. Site-directed mutagenesis and high-resolution NMR spectroscopy of the active site of porphobilinogen deaminase

    SciTech Connect

    Scott, A.I.; Roessner, C.A.; Stolowich, N.J.; Karuso, P.; Williams, H.J.; Grant, S.K.; Gonzalez, M.D.; Hoshino, T. )

    1988-10-18

    The active site of porphobilinogen (PBG){sup 1} deaminase from Escherichia coli has been found to contain an unusual dipyrromethane derived from four molecules of 5-aminolevulinic acid (ALA) covalently linked to Cys-242, one of the two cysteine residues conserved in E. coli and human deaminase. By use of a hemA{sup {minus}} strain of E. coli the enzyme was enriched from (5-{sup 13}C)ALA and examined by {sup 1}H-detected multiple quantum coherence spectroscopy, which revealed all of the salient features of a dipyrromethane composed of two PBG units linked heat to tail and terminating in a CH{sub 2}-S bond to a cysteine residue. Site-specific mutagenesis of Cys-99 and Cys-242, respectively, has shown that substitution of Ser for Cys-99 does not affect the enzymatic activity, whereas substitution of Ser for Cys-242 removes essentially all of the catalytic activity as measured by the conversion of the substrate PBG to uro'gen I. The NMR spectrum of the covalent complex of deaminase with the suicide inhibitor 2-bromo-(2,11-{sup 13}C{sub 2})PBG reveals that the aminomethyl terminus of the inhibitor reacts with the enzyme's cofactor at the {alpha}-free pyrrole. NMR spectroscopy of the ES{sub 2} complex confirmed a PBG-derived head-to-tail dipyrromethane attached to the {alpha}-free pyrrole position of the enzyme. A mechanistic rationale for deaminase is presented.

  18. High-resolution crystal structure of a polyextreme GH43 glycosidase from Halothermothrix orenii with α-l-arabinofuranosidase activity

    SciTech Connect

    Hassan, Noor; Kori, Lokesh D.; Gandini, Rosaria; Patel, Bharat K. C.; Divne, Christina; Tan, Tien Chye

    2015-02-19

    The crystal structure of the H. orenii glycosidase was determined by molecular replacement and refined at 1.10 Å resolution. A gene from the heterotrophic, halothermophilic marine bacterium Halothermothrix orenii has been cloned and overexpressed in Escherichia coli. This gene encodes the only glycoside hydrolase of family 43 (GH43) produced by H. orenii. The crystal structure of the H. orenii glycosidase was determined by molecular replacement and refined at 1.10 Å resolution. As for other GH43 members, the enzyme folds as a five-bladed β-propeller. The structure features a metal-binding site on the propeller axis, near the active site. Based on thermal denaturation data, the H. orenii glycosidase depends on divalent cations in combination with high salt for optimal thermal stability against unfolding. A maximum melting temperature of 76°C was observed in the presence of 4 M NaCl and Mn{sup 2+} at pH 6.5. The gene encoding the H. orenii GH43 enzyme has previously been annotated as a putative α-l-arabinofuranosidase. Activity was detected with p-nitrophenyl-α-l-arabinofuranoside as a substrate, and therefore the name HoAraf43 was suggested for the enzyme. In agreement with the conditions for optimal thermal stability against unfolding, the highest arabinofuranosidase activity was obtained in the presence of 4 M NaCl and Mn{sup 2+} at pH 6.5, giving a specific activity of 20–36 µmol min{sup −1} mg{sup −1}. The active site is structurally distinct from those of other GH43 members, including arabinanases, arabinofuranosidases and xylanases. This probably reflects the special requirements for degrading the unique biomass available in highly saline aqueous ecosystems, such as halophilic algae and halophytes. The amino-acid distribution of HoAraf43 has similarities to those of mesophiles, thermophiles and halophiles, but also has unique features, for example more hydrophobic amino acids on the surface and fewer buried charged residues.

  19. High-Resolution fMRI Maps of Cortical Activation in Nonhuman Primates: Correlation with Intrinsic Signal Optical Images

    PubMed Central

    Roe, Anna W.; Chen, Li Min

    2009-01-01

    One of the most widely used functional brain mapping tools is blood oxygen level–dependent (BOLD) functional magnetic resonance imaging (fMRI). This method has contributed to new understandings of the functional roles of different areas in the human brain. However, its ability to map cerebral cortex at high spatial (submillimeter) resolution is still unknown. Other methods such as single- and multiunit electrophysiology and intrinsic signal optical imaging have revealed submillimeter resolution of sensory topography and cortical columnar activations. However, they are limited either by spatial scale (electrophysiology characterizes only local groups of neurons) or by the inability to monitor deep structures in the brain (i.e., cortical regions buried in sulci or subcortical structures). A method that could monitor all regions of the brain at high spatial resolution would be ideal. This capacity would open the doors to investigating, for example, how networks of cerebral cortical columns relate to or produce behavior. In this article we demonstrate that, without benefit of contrast agents, at a magnetic field strength of 9.4 tesla, BOLD fMRI can reveal millimeter-sized topographic maps of digit representation in the somatosensory cortex of the anesthetized squirrel monkey. Furthermore, by mapping the “funneling illusion,” it is possible to detect even submillimeter shifts in activation in the cortex. Our data suggest that at high magnetic field strength, the positive BOLD signal can be used to reveal high spatial resolution maps of brain activity, a finding that weakens previous notions about the ultimate spatial specificity of the positive BOLD signal. PMID:18172338

  20. Mapping high-resolution incident photosynthetically active radiation over land surfaces from MODIS and GOES satellite data

    NASA Astrophysics Data System (ADS)

    Liang, S.; Wang, K.; Wang, D.; Townshend, J.; Running, S.; Tsay, S.

    2008-05-01

    Incident photosynthetically active radiation (PAR) is a key variable required by almost all terrestrial ecosystem models. Many radiation efficiency models are linearly related canopy productivity to the absorbed PAR. Unfortunately, the current incident PAR products estimated from remotely sensed data or calculated by radiation models at spatial and temporal resolutions are not sufficient for carbon cycle modeling and various applications. In this study, we aim to develop incident PAR products at one kilometer scale from multiple satellite sensors, such as Moderate Resolution Imaging Spectrometer (MODIS) and Geostationary Operational Environmental Satellite (GOES) sensor. We first developed a look-up table approach to estimate instantanerous incident PAR product from MODIS (Liang et al., 2006). The temporal observations of each pixel are used to estimate land surface reflectance and look-up tables of both aerosol and cloud are searched, based on the top-of-atmosphere reflectance and surface reflectance for determining incident PAR. The incident PAR product includes both the direct and diffuse components. The calculation of a daily integrated PAR using two different methods has also been developed (Wang, et al., 2008a). The similar algorithm has been further extended to GOES data (Wang, et al., 2008b, Zheng, et al., 2008). Extensive validation activities are conducted to evaluate the algorithms and products using the ground measurements from FLUXNET and other networks. They are also compared with other satellite products. The results indicate that our approaches can produce reasonable PAR product at 1km resolution. We have generated 1km incident PAR products over North America for several years, which are freely available to the science community. Liang, S., T. Zheng, R. Liu, H. Fang, S. C. Tsay, S. Running, (2006), Estimation of incident Photosynthetically Active Radiation from MODIS Data, Journal of Geophysical Research ¡§CAtmosphere. 111, D15208,doi:10

  1. Detection of macrophage activity in atherosclerosis in vivo using multichannel, high-resolution laser scanning fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Pande, Ashvin N.; Kohler, Rainer; Aikawa, Elena; Weissleder, Ralph; Jaffer, Farouc

    2006-03-01

    Molecular and cellular mechanisms of atherogenesis and its treatment are largely being unraveled by in vitro techniques. We describe methodology to directly image macrophage cell activity in vivo in a murine model of atherosclerosis using laser scanning fluorescence microscopy (LSFM) and a macrophage-targeted, near-infrared fluorescent (NIRF) magnetofluorescent nanoparticle (MFNP). Atherosclerotic apolipoprotein E deficient (apoE -/-) mice (n=10) are injected with MFNP or 0.9% saline, and wild-type mice (n=4) are injected with MFNP as additional controls. After 24 h, common carotid arteries are surgically exposed and prepared for LSFM. Multichannel LSFM of MFNP-enhanced carotid atheroma (5×5-µm in-plane resolution) shows a strong focal NIRF signal, with a plaque target-to-background ratio of 3.9+/-1.8. Minimal NIRF signal is observed in control mice. Spectrally resolved indocyanine green (ICG) fluorescence angiograms confirm the intravascular location of atheroma. On ex vivo fluorescence reflectance imaging, greater NIRF plaque signal is seen in apoE -/- MFNP mice compared to controls (p<0.01). The NIRF signal correlates well with immunostained macrophages, both by stained surface area (r=0.77) and macrophage number (r=0.86). The validated experimental methodology thus establishes a platform for investigating macrophage activity in atherosclerosis in vivo, and has implications for the detection of clinical vulnerable plaques.

  2. The Europa Imaging System (EIS): High-Resolution, 3-D Insight into Europa's Geology, Ice Shell, and Potential for Current Activity

    NASA Astrophysics Data System (ADS)

    Turtle, E. P.; McEwen, A. S.; Collins, G. C.; Fletcher, L. N.; Hansen, C. J.; Hayes, A.; Hurford, T., Jr.; Kirk, R. L.; Barr, A.; Nimmo, F.; Patterson, G.; Quick, L. C.; Soderblom, J. M.; Thomas, N.

    2015-12-01

    The Europa Imaging System will transform our understanding of Europa through global decameter-scale coverage, three-dimensional maps, and unprecedented meter-scale imaging. EIS combines narrow-angle and wide-angle cameras (NAC and WAC) designed to address high-priority Europa science and reconnaissance goals. It will: (A) Characterize the ice shell by constraining its thickness and correlating surface features with subsurface structures detected by ice penetrating radar; (B) Constrain formation processes of surface features and the potential for current activity by characterizing endogenic structures, surface units, global cross-cutting relationships, and relationships to Europa's subsurface structure, and by searching for evidence of recent activity, including potential plumes; and (C) Characterize scientifically compelling landing sites and hazards by determining the nature of the surface at scales relevant to a potential lander. The NAC provides very high-resolution, stereo reconnaissance, generating 2-km-wide swaths at 0.5-m pixel scale from 50-km altitude, and uses a gimbal to enable independent targeting. NAC observations also include: near-global (>95%) mapping of Europa at ≤50-m pixel scale (to date, only ~14% of Europa has been imaged at ≤500 m/pixel, with best pixel scale 6 m); regional and high-resolution stereo imaging at <1-m/pixel; and high-phase-angle observations for plume searches. The WAC is designed to acquire pushbroom stereo swaths along flyby ground-tracks, generating digital topographic models with 32-m spatial scale and 4-m vertical precision from 50-km altitude. These data support characterization of cross-track clutter for radar sounding. The WAC also performs pushbroom color imaging with 6 broadband filters (350-1050 nm) to map surface units and correlations with geologic features and topography. EIS will provide comprehensive data sets essential to fulfilling the goal of exploring Europa to investigate its habitability and perform

  3. The Europa Imaging System (EIS): High-Resolution, 3-D Insight into Europa's Geology, Ice Shell, and Potential for Current Activity

    NASA Astrophysics Data System (ADS)

    Turtle, E. P.; McEwen, A. S.; Collins, G. C.; Fletcher, L. N.; Hansen, C. J.; Hayes, A.; Hurford, T., Jr.; Kirk, R. L.; Barr, A.; Nimmo, F.; Patterson, G.; Quick, L. C.; Soderblom, J. M.; Thomas, N.

    2014-12-01

    The Europa Imaging System will transform our understanding of Europa through global decameter-scale coverage, three-dimensional maps, and unprecedented meter-scale imaging. EIS combines narrow-angle and wide-angle cameras (NAC and WAC) designed to address high-priority Europa science and reconnaissance goals. It will: (A) Characterize the ice shell by constraining its thickness and correlating surface features with subsurface structures detected by ice penetrating radar; (B) Constrain formation processes of surface features and the potential for current activity by characterizing endogenic structures, surface units, global cross-cutting relationships, and relationships to Europa's subsurface structure, and by searching for evidence of recent activity, including potential plumes; and (C) Characterize scientifically compelling landing sites and hazards by determining the nature of the surface at scales relevant to a potential lander. The NAC provides very high-resolution, stereo reconnaissance, generating 2-km-wide swaths at 0.5-m pixel scale from 50-km altitude, and uses a gimbal to enable independent targeting. NAC observations also include: near-global (>95%) mapping of Europa at ≤50-m pixel scale (to date, only ~14% of Europa has been imaged at ≤500 m/pixel, with best pixel scale 6 m); regional and high-resolution stereo imaging at <1-m/pixel; and high-phase-angle observations for plume searches. The WAC is designed to acquire pushbroom stereo swaths along flyby ground-tracks, generating digital topographic models with 32-m spatial scale and 4-m vertical precision from 50-km altitude. These data support characterization of cross-track clutter for radar sounding. The WAC also performs pushbroom color imaging with 6 broadband filters (350-1050 nm) to map surface units and correlations with geologic features and topography. EIS will provide comprehensive data sets essential to fulfilling the goal of exploring Europa to investigate its habitability and perform

  4. Towards widespread exploitation of high resolution multi-temporal interferometry for monitoring landslide activity: a case-study of Southern Gansu, China

    NASA Astrophysics Data System (ADS)

    Wasowski, Janusz; Bovenga, Fabio; Dijkstra, Tom; Meng, Xingmin; Nutricato, Raffaele; Chiaradia, Maria Teresa

    2014-05-01

    Although Multi-Temporal Interferometry (MTI) techniques are considered to have already reached the operational level, it is apparent that, in both research and practice, we are only just beginning to benefit from the high resolution imagery that is currently acquired by the new generation of radar satellites. MTI techniques are not applicable in any environment, but, nonetheless, we foresee a strong possibility that in the future these techniques will see widespread exploitation in support of slope hazard assessments. MTI applications will become increasingly important in cases where little or no conventional monitoring is feasible (e.g. remote locations and limited funds). The tremendous potential of MTI is illustrated using selected examples of applications ranging from local to catchment scales. A particular focus is on the use of MTI for the investigation of slope instability in the remote high mountain region of Zhouqu, Southern Gansu, known to be affected by large magnitude (M7-8) earthquakes and catastrophic mass movements. The MTI processing of high resolution (~3 m) COSMO/SkyMed (CSK) satellite images produced spatially dense information (more than 1000 radar targets/km2) on ground surface displacements. A substantial portion of the radar targets showed significant displacements (from few to over 100 mm/yr), denoting widespread slope instability. In particular, the MTI results provided valuable information on the activity of some very large, apparently slow moving landslides that represent a persistent hazard to the local population and infrastructure, particularly as these landslides are known to undergo periods of increased activity resulting in river damming and disastrous flooding. Given the general lack of field monitoring data on slope instability in Southern Gansu, the MTI-derived displacements offer a unique form of remote displacement monitoring that provides valuable information to experts tasked with formulating strategies for hazard management

  5. High-resolution music with inaudible high-frequency components produces a lagged effect on human electroencephalographic activities.

    PubMed

    Kuribayashi, Ryuma; Yamamoto, Ryuta; Nittono, Hiroshi

    2014-06-18

    High-quality digital sound sources with inaudible high-frequency components (above 20 kHz) have become available because of recent advances in information technology. Listening to such sounds has been shown to increase the α-band power of an electroencephalogram (EEG). The present study scrutinized the time course of this effect by recording EEG along with autonomic measures (skin conductance level and heart rate) and facial electromyograms (corrugator supercilii and zygomaticus major). Twenty university students (19-24 years old) listened to two types of a 200-s musical excerpt (J. S. Bach's French Suite No. 5) with or without inaudible high-frequency components using a double-blind method. They were asked to rate the sound quality and to judge which excerpt contained high-frequency components. High-α EEG power (10.5-13 Hz) was larger for the excerpt with high-frequency components than for the excerpt without them. This effect was statistically significant only in the last quarter of the period (150-200 s). Participants were not able to distinguish between the excerpts, which did not produce any discernible differences in subjective, autonomic, and facial muscle measures. This study shows that inaudible high-frequency components have an impact on human brain activity without conscious awareness. Unlike a standard test for sound quality, at least 150 s of exposure is required to examine this effect in future research. PMID:24722228

  6. High-resolution shallow reflection seismic image and surface evidence of the Upper Tiber Basin active faults (Northern Apennines, Italy)

    USGS Publications Warehouse

    Donne, D.D.; Plccardi, L.; Odum, J.K.; Stephenson, W.J.; Williams, R.A.

    2007-01-01

    Shallow seismic reflection prospecting has been carried out in order to investigate the faults that bound to the southwest and northeast the Quaternary Upper Tiber Basin (Northern Apennines, Italy). On the northeastern margin of the basin a ??? 1 km long reflection seismic profile images a fault segment and the associated up to 100 meters thick sediment wedge. Across the southwestern margin a 0.5 km-long seismic profile images a 50-55??-dipping extensional fault, that projects to the scarp at the base of the range-front, and against which a 100 m thick syn-tectonic sediment wedge has formed. The integration of surface and sub-surface data allows to estimate at least 190 meters of vertical displacement along the fault and a slip rate around 0.25 m/kyr. Southwestern fault might also be interpreted as the main splay structure of regional Alto Tiberina extensional fault. At last, the 1917 Monterchi earthquake (Imax=X, Boschi et alii, 2000) is correlable with an activation of the southwestern fault, and thus suggesting the seismogenic character of this latter.

  7. High Resolution Formaldehyde Photochemistry

    NASA Astrophysics Data System (ADS)

    Ernest, C. T.; Bauer, D.; Hynes, A. J.

    2010-12-01

    Formaldehyde (HCHO) is the most abundant and most important organic carbonyl compound in the atmosphere. The sources of formaldehyde are the oxidation of methane, isoprene, acetone, and other volatile organic compounds (VOCs); fossil fuel combustion; and biomass burning. The dominant loss mechanism for formaldehyde is photolysis which occurs via two pathways: (R1) HCHO + hv → HCO + H (R2) HCHO + hv → H2 + CO The first pathway (R1) is referred to as the radical channel, while the second pathway (R2) is referred to as the molecular channel. The products of both pathways play a significant role in atmospheric chemistry. The CO that is produced in the molecular channel undergoes further oxidation to produce CO2. Under atmospheric conditions, the H atom and formyl radical that are produced in the radical channel undergo rapid reactions with O2 to produce the hydroperoxyl radical (HO2) via (R3) and (R4). (R3) HCO + O2 → HO2 + CO (R4) H + O2 → HO2 Thus, for every photon absorbed, the photolysis of formaldehyde can contribute one CO2 molecule to the global greenhouse budget or two HO2 radicals to the tropospheric HOx (OH + HO2) cycle. The HO2 radicals produced during formaldehyde photolysis have also been implicated in the formation of photochemical smog. The HO2 radicals act as radical chain carriers and convert NO to NO2, which ultimately results in the catalytic production of O3. Constraining the yield of HO2 produced via HCHO photolysis is essential for improving tropospheric chemistry models. In this study, both the absorption cross section and the quantum yield of the radical channel (R1) were measured at high resolution over the tropospherically relevant wavelength range 304-330 nm. For the cross section measurements a narrow linewidth Nd:YAG pumped dye laser was used with a multi-pass cell. Partial pressures of HCHO were kept below 0.3 torr. Simultaneous measurement of OH LIF in a flame allowed absolute calibration of the wavelength scale. Pressure

  8. A high-resolution spectroscopic survey of late-type stars: chromospheric activity, rotation, kinematics, and age

    NASA Astrophysics Data System (ADS)

    López-Santiago, J.; Montes, D.; Gálvez-Ortiz, M. C.; Crespo-Chacón, I.; Martínez-Arnáiz, R. M.; Fernández-Figueroa, M. J.; de Castro, E.; Cornide, M.

    2010-05-01

    Aims: We present a compilation of spectroscopic data from a survey of 144 chromospherically active young stars in the solar neighborhood, which may be used to investigate different aspects of its formation and evolution in terms of kinematics and stellar formation history. The data have already been used by us in several studies. With this paper, we make all these data accessible to the scientific community for future studies on different topics. Methods: We performed spectroscopic observations with echelle spectrographs to cover the entirety of the optical spectral range simultaneously. Standard data reduction was performed with the IRAF echelle package. We applied the spectral subtraction technique to reveal chromospheric emission in the stars of the sample. The equivalent width of chromospheric emission lines was measured in the subtracted spectra and then converted to fluxes using equivalent width-flux relationships. Radial and rotational velocities were determined by the cross-correlation technique. Kinematics, equivalent widths of the lithium line λ6707.8 Å and spectral types were also determined. Results: A catalog of spectroscopic data is compiled: radial and rotational velocities, space motion, equivalent widths of optical chromospheric activity indicators from Ca II H & K to the calcium infrared triplet and the lithium line in λ6708 Å. Fluxes in the chromospheric emission lines and R'_HK are also determined for each observation of a star in the sample. We used these data to investigate the emission levels of our stars. The study of the Hα emission line revealed two different populations of chromospheric emitters in the sample, clearly separated in the logFHα/Fbol - (V-J) diagram. The dichotomy may be associated with the age of the stars. Based on observations made with the 2.2 m telescope of the German-Spanish Astronomical Centre, Calar Alto (Almería, Spain), operated jointly by the Max-Planck-Institute for Astronomy, Heidelberg, and the Spanish

  9. High resolution tree-ring based spatial reconstructions of snow avalanche activity in Glacier National Park, Montana, USA

    USGS Publications Warehouse

    Pederson, Gregory T.; Reardon, Blase; Caruso, C.J.; Fagre, Daniel B.

    2006-01-01

    Effective design of avalanche hazard mitigation measures requires long-term records of natural avalanche frequency and extent. Such records are also vital for determining whether natural avalanche frequency and extent vary over time due to climatic or biophysical changes. Where historic records are lacking, an accepted substitute is a chronology developed from tree-ring responses to avalanche-induced damage. This study evaluates a method for using tree-ring chronologies to provide spatially explicit differentiations of avalanche frequency and temporally explicit records of avalanche extent that are often lacking. The study area - part of John F. Stevens Canyon on the southern border of Glacier National Park – is within a heavily used railroad and highway corridor with two dozen active avalanche paths. Using a spatially geo-referenced network of avalanche-damaged trees (n=109) from a single path, we reconstructed a 96-year tree-ring based chronology of avalanche extent and frequency. Comparison of the chronology with historic records revealed that trees recorded all known events as well as the same number of previously unidentified events. Kriging methods provided spatially explicit estimates of avalanche return periods. Estimated return periods for the entire avalanche path averaged 3.2 years. Within this path, return intervals ranged from ~2.3 yrs in the lower track, to ~9-11 yrs and ~12 to >25 yrs in the runout zone, where the railroad and highway are located. For avalanche professionals, engineers, and transportation managers this technique proves a powerful tool in landscape risk assessment and decision making.

  10. High resolution time interval meter

    DOEpatents

    Martin, A.D.

    1986-05-09

    Method and apparatus are provided for measuring the time interval between two events to a higher resolution than reliability available from conventional circuits and component. An internal clock pulse is provided at a frequency compatible with conventional component operating frequencies for reliable operation. Lumped constant delay circuits are provided for generating outputs at delay intervals corresponding to the desired high resolution. An initiation START pulse is input to generate first high resolution data. A termination STOP pulse is input to generate second high resolution data. Internal counters count at the low frequency internal clock pulse rate between the START and STOP pulses. The first and second high resolution data are logically combined to directly provide high resolution data to one counter and correct the count in the low resolution counter to obtain a high resolution time interval measurement.

  11. Evaluation of the heat-storage capability of shallow aquifers using active heat tracer tests and Fiber-Optics Distributed-Temperature-Sensing

    NASA Astrophysics Data System (ADS)

    Suibert Oskar Seibertz, Klodwig; Chirila, Marian Andrei; Bumberger, Jan; Dietrich, Peter; Vienken, Thomas

    2015-04-01

    In the course of the energy transition, geothermal energy storage and heat generation and cooling have proven to be environmental friendly alternatives to conventional energy. However, to ensure sustain usage, the heat transport behavior of aquifers and its distribution has to be studied. A tool to achieve this is the active heat tracer test, eg. Leaf et al. (2012). If active heat tracer tests are combined with in aquifer heat testing via electric heating-cables, eg. Liu et al. (2013), it is possible to observe heat transport and temperature signal decay without disturbing the original pressure field within the aquifer. In this field study a two channel High-Resolution-Fiber-Optic-Distributed-Temperature-Sensing and Pt100 were used to measure temperature signals within in two wells of 1.4 m distance, where the temperature difference was generated using a self regulating heating cable in the upstream well. High resolution Distributed-Temperature-Sensing measurements were achieved by coiling the fiber around screened plastic tubes. The upstream well was also used to observe heating (Δ Tmax approx. 24K) and temperature signal decay, while the downstream well was used to observe heat transport between both wells. The data was analyzed and compared to thermal conductivity of soil samples and Direct-Push (DP) Electrical-Conductivity-Logging and DP Hydraulic-Profiling results. The results show good agreement between DP data and temperature measurements proving the active heat tracer test is a suitable tool for providing reliable information on aquifer heat-storage capability. References Leaf, A.T., Hart, D.J., Bahr, J.M.: Active Thermal Tracer Tests for Improved Hydrostratigraphic Characterization. Ground Water, vol. 50, 2012 Liu, G., Knobbe, S., Butler, J.J.Jr.: Resolving centimeter-scale flows in aquifers and their hydrostratigraphic controls. Geophysical Research Letters, vol. 40, 2013

  12. Overview of Proposal on High Resolution Climate Model Simulations of Recent Hurricane and Typhoon Activity: The Impact of SSTs and the Madden Julian Oscillation

    NASA Technical Reports Server (NTRS)

    Schubert, Siegfried; Kang, In-Sik; Reale, Oreste

    2009-01-01

    This talk gives an update on the progress and further plans for a coordinated project to carry out and analyze high-resolution simulations of tropical storm activity with a number of state-of-the-art global climate models. Issues addressed include, the mechanisms by which SSTs control tropical storm. activity on inter-annual and longer time scales, the modulation of that activity by the Madden Julian Oscillation on sub-seasonal time scales, as well as the sensitivity of the results to model formulation. The project also encourages companion coarser resolution runs to help assess resolution dependence, and. the ability of the models to capture the large-scale and long-terra changes in the parameters important for hurricane development. Addressing the above science questions is critical to understanding the nature of the variability of the Asian-Australian monsoon and its regional impacts, and thus CLIVAR RAMP fully endorses the proposed tropical storm simulation activity. The project is open to all interested organizations and investigators, and the results from the runs will be shared among the participants, as well as made available to the broader scientific community for analysis.

  13. Active Processes On The Sw Iberian Margin: High-resolution Sidescan Sonar Mapping Of The "marques De Pombal" Fault And Associated Structures

    NASA Astrophysics Data System (ADS)

    Gràcia, E.; Dañobeitia, J. J.; Terrinha, P.; Blondel, P.; Farrán, M.; Jacobs, C.; Hits Cruise Party, The

    The SW Iberian Margin hosts the present-day boundary between the European and African Plates, and is characterized by a significant seismic activity, source of the largest earthquakes in Western Europe. One of the main goals of the recent HITS cruise ("High Resolution Imaging of Tsunamigenic Structures in SW Iberia"), carried out on board the RV Hesperides during September 2001, was to determine the geom- etry of active seismogenic structures and the flux and sediment instability associated with the tectonic activity. Two areas were surveyed using the high-resolution TOBI sidescan sonar together with swath-bathymetry and sub-bottom profiler, totalling more than 550 nm. On the first area, we identified a NNE-trending lineament, correspond- ing to the seafloor rupture of the 50 km long Marques de Pombal thrust fault (MPF), possible source of the 1755 Lisbon Earthquake and Tsunami. Associated to this struc- ture, we identified a fresh mass-wasting landslide complex covering an area of 20 km x 13 km. This large gravity deposit is made of two individual flows separated by an acoustically darker region. Both flows have a common source upslope displaying the headscarp and a set of slide blocks. At the northern termination of the MPF there are a series of folds and small fissures which accommodate present-day deformation. The most prominent feature is the Bow Spur, a reflective topographic high corresponding to a horst, probably inherited from the original architecture of the Mesozoic margin. The transfer zone to the south of the MPF was also imaged, showing localized scars and mass-wasting features. On the second area, the TOBI and swath-bathymetry im- ages show that the San Vicente Canyon is deeply incised into the seafloor with an asymmetric cross-section. The linear and angular appearance of its flanks strongly suggests that the canyon is fault-controlled. The bottom of the canyon, barren of re- cent sediments, appears highly reflective with corrugated surfaces which

  14. The Relationship Between Solar Coronal X-Ray Brightness and Active Region Magnetic Fields: A Study Using High-Resolution Hinode Observations

    NASA Astrophysics Data System (ADS)

    Hazra, Soumitra; Nandy, Dibyendu; Ravindra, B.

    2015-03-01

    By using high-resolution observations of nearly co-temporal and co-spatial Solar Optical Telescope spectropolarimeter and X-Ray Telescope coronal X-ray data onboard Hinode, we revisit the problematic relationship between global magnetic quantities and coronal X-ray brightness. Co-aligned vector magnetogram and X-ray data were used for this study. The total X-ray brightness over active regions is well correlated with integrated magnetic quantities such as the total unsigned magnetic flux, the total unsigned vertical current, and the area-integrated square of the vertical and horizontal magnetic fields. On accounting for the inter-dependence of the magnetic quantities, we inferred that the total magnetic flux is the primary determinant of the observed integrated X-ray brightness. Our observations indicate that a stronger coronal X-ray flux is not related to a higher non-potentiality of active-region magnetic fields. The data even suggest a slightly negative correlation between X-ray brightness and a proxy of active-region non-potentiality. Although there are small numerical differences in the established correlations, the main conclusions are qualitatively consistent over two different X-ray filters, the Al-poly and Ti-poly filters, which confirms the strength of our conclusions and validate and extend earlier studies that used low-resolution data. We discuss the implications of our results and the constraints they set on theories of solar coronal heating.

  15. The Vallo di Diano Range-Bounding Fault System (Southern Italy): New Evidence of Recent Activity From High-Resolution Seismic Profiling

    NASA Astrophysics Data System (ADS)

    Castiello, A.; Villani, F.; Bruno, P.; Improta, L.; De Rosa, D.; di Fiore, V.; Punzo, M.; Varriale, F.; Montone, P.; Pierdominici, S.; Rapolla, A.

    2008-12-01

    The Vallo di Diano is the largest intermountain basin in the Southern Apennines (Italy). The basin evolution was controlled by the Quaternary activity of a range-bounding, SW-dipping normal fault system located to the east (Vallo di Diano Fault System, VDFS). Geological and oil industry data define the sin-sedimentary activity of the VDFS up to the Middle Pleistocene. However, commercial profiles do not resolve the shallower, eastern portion of the basin, due to strong lateral heterogeneities and unfavourable surface conditions. Therefore, Late Pleistocene-Holocene activity of the VDFS and its seismogenic potential are still uncertain. To better constrain the shallow structure of the basin, we performed four high-resolution seismic surveys, along its eastern side, where slope breccias and fans cover the Mesozoic carbonate bedrock and bury the VDFS. We also investigated some NW-trending flexures affecting Late Pleistocene fans, that we had previously detected and dubitatively ascribed to recent faulting. Seismic data were acquired with a dense wide-aperture geometry. Two high-resolution (HR) NE-trending profiles, about 1.5 km long, were collected using respectively 5 m and 10 m spaced receivers and sources. Two very high-resolution (VHR) NE-trending profiles, 400 and 350 m long, with densely spaced sources (4 m) and receivers (2 m) were also collected. HR profiling was aimed at imaging alluvial fan thickness and morphology of the underlying carbonate bedrock. VHR surveys targeted the flexures and their possible origin. All lines were acquired with a HR vibroseis source, except for the shortest profile, where we used a buffalo-gun, better suited for very near-surface imaging (z < 50 m depth). Seismic imaging consists of reflectivity images obtained by CDP-processing of reflection data complemented by Vp images obtained by multi-scale seismic tomography. The stack sections illuminated the basin down to 0.4-0.5 s TWT and reveal an array of high-angle, generally SW

  16. Late Quaternary Activity on the Cerro Goden Fault, Puerto Rico and Limitations of High-resolution Seismic Reflection/refraction Data for Trench-scale Investigations

    NASA Astrophysics Data System (ADS)

    Zachariasen, J.; Prentice, C. S.; Schweig, E.; Abreu, R.; Rymer, M. J.; Catchings, R. D.

    2005-12-01

    The Cerro Goden Fault runs along the base of the La Cadena de San Francisco range north of Añasco in western Puerto Rico, and joins with the Great Southern Puerto Rico Fault zone. This fault zone disrupts Eocene and older rocks but its Quaternary history is unclear. It bounds the northern Añasco Valley, which is seismically active. Offshore investigations suggest the fault cuts the sea floor (Grindlay et al., 2005) and an onshore reconnaissance study by Mann et al. (2005) found geomorphic evidence of Quaternary displacement. We gathered high-resolution seismic reflection/refraction data along two lines that crossed the projection of the fault in the Añasco Valley to help identify possible fault strands in the near subsurface. The seismic data were gathered using a shoot-through acquisition method with a BETSY-Seisgun shooting source consisting of 8-gauge, 400 grain shotgun blanks set in holes drilled about 30 cm below the ground surface. Both lines had shot and geophone spacings of 5 m. Common Depth Point (CDP) spacings for both lines were 2.5 m in the shallow section of the profiles. We used the results from the seismic lines to site six trenches where the data revealed discontinuities, possibly attributable to faulting, within the upper 2-3 meters. Our trenches ranged in depth from 2 - 5 meters, but in none of the trenches did we find evidence of surface faulting. A mountain-front-facing subsurface scarp, which may have been produced by older Quaternary faulting, appeared in several trenches. Holocene fluvial sediments have been deposited against this scarp and have buried it, but are unfaulted. Our results suggest either that the Cerro Goden Fault has not been active since the deposition of the Holocene fluvial sediments or that the high-resolution seismic data were not adequate to define the location of fault traces to the precision necessary for trench investigations. Both the seismic data and the buried scarps suggest there may be faults at depth, but

  17. High Resolution Doppler Lidar

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This Grant supported the development of an incoherent lidar system to measure winds and aerosols in the lower atmosphere. During this period the following activities occurred: (1) an active feedback system was developed to improve the laser frequency stability; (2) a detailed forward model of the instrument was developed to take into account many subtle effects, such as detector non-linearity; (3) a non-linear least squares inversion method was developed to recover the Doppler shift and aerosol backscatter without requiring assumptions about the molecular component of the signal; (4) a study was done of the effects of systematic errors due to multiple etalon misalignment. It was discovered that even for small offsets and high aerosol loadings, the wind determination can be biased by as much as 1 m/s. The forward model and inversion process were modified to account for this effect; and (5) the lidar measurements were validated using rawinsonde balloon measurements. The measurements were found to be in agreement within 1-2 m/s.

  18. Structure and evolution of the seismically active Ostler Fault Zone (New Zealand) based on interpretations of multiple high resolution seismic reflection profiles

    NASA Astrophysics Data System (ADS)

    Campbell, Fiona M.; Ghisetti, Francesca; Kaiser, Anna E.; Green, Alan G.; Horstmeyer, Heinrich; Gorman, Andrew R.

    2010-12-01

    To improve our understanding of active faulting away from the main plate boundary on New Zealand's South Island, we have acquired high resolution seismic data across the Ostler Fault Zone Twelve 1.2 km long lines perpendicular to fault strike and a 1.6 km long crossline were collected in a region of the MacKenzie Basin where surface mapping delineates significant complexity in the form of two non-overlapping reverse fault strands separated by a transfer zone characterised by multiple smaller strands and increased folding. Interpretation of the resultant images includes a 45-55° west-dipping principal fault and two 25-30° west-dipping subsidiary faults, one in the hanging wall and one in the footwall of the principal fault. The geologically mapped complexities are shown to be caused by shallow variations in the structure of the principal fault, which breaks the surface in the north and south but not within the transfer zone, where it forms a triangle zone with associated backthrusting and minor faulting. These complexities only extend to ~ 300 m depth. Structures below this level are markedly simpler and much more 2D in nature, with the principal fault strand extending over a much longer distance than the individual strands observed at the surface. Since longer faults are susceptible to larger earthquakes than shorter ones, seismic hazard at the study site may be higher than previously thought. Multiple surface fault strands that give way to a single more major stand at relatively shallow depths may be a common feature of segmented fault systems. The deepest layered reflections at our site are consistent with the presence of a Late Cretaceous (?)-Tertiary basin underlying the present-day MacKenzie Basin. Structural restoration of the seismic images back to the base of Quaternary fluvioglacial terraces and back to the top of a Late Pliocene-Pleistocene fluviolacustrine unit indicate that compression was initiated prior to the Late Pliocene and that it has continued

  19. High resolution telescope

    SciTech Connect

    Massie, N.A.; Oster, Y.

    1990-01-01

    A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employs speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1m in a circle-of-nine configuration. The telescope array has an effective aperture of 12m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by an electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes. 9 figs., 1 tab.

  20. High resolution telescope

    SciTech Connect

    Massie, N.A.; Oster, Y.

    1990-12-31

    A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employs speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1m in a circle-of-nine configuration. The telescope array has an effective aperture of 12m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by an electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes. 9 figs., 1 tab.

  1. High resolution 3D P wave velocity structure beneath Tenerife Island (Canary Islands, Spain) based on tomographic inversion of active-source data

    NASA Astrophysics Data System (ADS)

    GarcíA-Yeguas, Araceli; Koulakov, Ivan; IbáñEz, Jesús M.; Rietbrock, A.

    2012-09-01

    We present a high resolution 3 dimensional (3D) P wave velocity model for Tenerife Island, Canaries, covering the top of Teide volcano (3,718 m a.s.l.) down to around 8 km below sea level (b.s.l). The tomographic inversion is based on a large data set of travel times obtained from a 3D active seismic experiment using offshore shots (air guns) recorded at more than 100 onshore seismic stations. The obtained seismic velocity structure is strongly heterogeneous with significant (up to 40%) lateral variations. The main volcanic structure of the Las Cañadas-Teide-Pico Viejo Complex (CTPVC) is characterized by a high P wave velocity body, similar to many other stratovolcanoes. The presence of different high P wave velocity regions inside the CTPVC may be related to the geological and volcanological evolution of the system. The presence of high P wave velocities at the center of the island is interpreted as evidence for a single central volcanic source for the formation of Tenerife. Furthermore, reduced P wave velocities are found in a small confined region in CTPVC and are more likely related to hydrothermal alteration, as indicated by the existence of fumaroles, than to the presence of a magma chamber beneath the system. In the external regions, surrounding CTPVC a few lower P wave velocity regions can be interpreted as fractured zones, hydrothermal alterations, porous materials and thick volcaniclastic deposits.

  2. Definition and Paleoseismology of the Active, Left-Lateral Enriquillo-Plantain Garden Fault Zone Based on High-Resolution Chirp Profiles: Lakes Azuey and Mirogoane, Haiti

    NASA Astrophysics Data System (ADS)

    Wang, J.; Mann, P.; von Lignau, A. V.

    2014-12-01

    In July 2014, we obtained a total of 94 km of high-resolution Chirp profiles from the 129 km2, brackish Lake Azuey and 37 km of profiles from the 14 km2, fresh water Lake Mirogoane that both straddle the active trace of the Enriquillo-Plantain Garden fault zone (EPGFZ) of Haiti. 80% of the grid on Azuey and 85% on Mirogoane was dedicated to north-south profiles of the EPGFZ. In Azuey we defined the linear and east-west-striking fault trace in deformed Holocene sediments along with its landfalls west of Lake Azuey in Haiti and east of Lake Azuey in the Dominican Republic. All profiles showed the fault to be a sub-vertical flower structure whose active traces could be traced on Chirp data to a depth of 30 m below the lake floor. Previous workers have suggested that this fault ruptured during a large November, 1751, earthquake with a parallel and elongate felt zone. We hypothesize the most recent break of the fault several meters below the lake floor to have formed during the 1751 event but plan a coring program to precisely constrain the timing of historical and prehistorical events based on syn-faulting colluvial wedges observed on Chirp profiles. Our survey of Mirogoane confirmed its rhomboidal pull-apart structure with the basin center at a depth of 42-8 m making this basin the deepest lake in the Caribbean region. Deformational features include active folds at the lake bottom, large oblique-slip normal faults at an angle to the bounding east-west faults, and 30 m of recognizable stratigraphy. The 7 m of Holocene cored in the basin center in 1988 is observed to be highly deformed and locally folded and overlies with angular unconformity a well stratified and more folded lower basinal unit. Historical events are proposed to have ruptured on or near this segment of the EPGFZ in 1701 and 1770.

  3. Active Strike-Slip Faulting in the Inner Continental Borderland, Southern California: Results From New High-Resolution Seismic Reflection Data

    NASA Astrophysics Data System (ADS)

    Conrad, J. E.; Ryan, H. F.; Sliter, R. W.

    2008-12-01

    The inner Continental Borderland offshore of southern California accommodates about 7 mm/yr of slip between the North American and Pacific plates. Nearly half of this total has previously been thought to be taken up on the Palos Verdes (PV) and Coronado Bank (CB) fault zones, which have been modeled as a single, continuous fault zone in recent seismic hazard assessments for southern California. Although these faults lie roughly on strike with each other, a connection between these faults has not been clearly demonstrated. Newly acquired high-resolution seismic reflection data indicate that the PV fault terminates southwest of Lasuen Knoll in a horsetail splay that becomes progressively buried to the south. The lack of a connection between the PV and CB fault zones implies that a significant amount of slip must be taken up elsewhere in the inner Continental Borderland. Two other significant offshore faults, the San Diego Trough (SDT) and San Pedro Basin (SPB) fault zones, lie about 10-15 km southwest of and sub parallel to the trace of the PV and CB faults. The SDT fault zone extends from south of the Mexican border near Punta Santo Tomas for about 150 km northward to near Crespi Knoll. The SPB fault zone extends northward from off Santa Catalina Island to near Point Dume. The new seismic reflection data reveal a previously unmapped but apparently active fault zone along strike and in the area between the known strands of the SDT and the SPB fault zones. This newly recognized fault links the SDT and SPB faults, forming a continuous, active fault zone that extends about 250 km along the inner Continental Borderland. Although there are no slip rate data available for this fault zone, its overall length, continuity, and active character suggest that a significant portion of the plate motion that occurs offshore is accommodated along the SDT-SPB fault zone, which may pose a more significant seismic hazard than previously recognized.

  4. 16ch high-resolution seismic reflection surveys on the active fault of upper fore-arc slope off Okinawa Island, central Ryukyu Island Arc, Southwest Japan

    NASA Astrophysics Data System (ADS)

    Arai, K.; Inoue, T.; Sato, T.; Tuzino, T.

    2010-12-01

    The Ryukyu Island Arc extends from Kyushu to Taiwan, a distance of 1,200 km, along the Ryukyu Trench where the Philippine Sea Plate is subducting beneath the Eurasian Plate. The Okinawa Trough, a back arc basin has formed behind the Ryukyu Island Arc in late Pliocene to early Pleistocene. The research cruises of GH08 (from 28th July to 29th August 2008) and GH09 (from 16th July to 17th August 2009) were carried out around Okinawa Island, which is located on the central Ryukyu Island Arc. More than 4,500 miles multi channel high-resolution seismic profiles were acquired during these two cruises by the GI-gun (355cu. inch) or the Cluster-gun (30+30 cu. inch) systems with 16ch digital streamer cable. Survey area in the southeast off Okinawa Island is located on the upper fore-arc slope. Seismic reflections of the upper fore-arc slope show a distinct reflector which may represent erosional unconformable surface. The distinct reflector had tilted southeastward and was overlain by the stratified sediments. No obvious deformation such as the fold and faults parallel to the Ryukyu Trench axis was found under the upper slope. In contrast, some active faults which were perpendicular to the Ryukyu Trench axis (NW-SE direction) were observed. The most conspicuous normal fault was found on north off Okinawa Island. The fault with 70-80°dipping toward northeast has been active since the early Pleistocene inferred from seismic stratigraphy and calcareous nannofossil biochronology. The maximum displacement reaches to 0.7 s two way travel time in depth. An average of maximum vertical displace component of the normal fault may reach up to ten cm/1000 years. Seismic profiles indicate that the tilting of Ryukyu Island Arc forward to the Ryukyu Trench plays the important role of formation of the fault in a NW-SE direction.

  5. Multiwavelength optical observations of chromospherically active binary systems. III. High resolution echelle spectra from Ca II H & K to Ca II IRT

    NASA Astrophysics Data System (ADS)

    Montes, D.; Fernández-Figueroa, M. J.; De Castro, E.; Cornide, M.; Latorre, A.; Sanz-Forcada, J.

    2000-10-01

    This is the third paper of a series aimed at studying the chromosphere of active binary systems using the information provided for several optical spectroscopic features. High resolution echelle spectra including all the optical chromospheric activity indicators from the Ca II H & K to Ca II IRT lines are analysed here for 16 systems. The chromospheric contribution in these lines has been determined using the spectral subtraction technique. Very broad wings have been found in the subtracted Hα profile of the very active star HU Vir. These profiles are well matched using a two-component Gaussian fit (narrow and broad) and the broad component can be interpreted as arising from microflaring. Red-shifted absorption features in the Hα line have been detected in several systems and excess emission in the blue wing of FG UMa was also detected. These features indicate that several dynamical processes, or a combination of them, may be involved. Using the E_Hα /E_Hβ ratio as a diagnostic we have detected prominence-like extended material viewed off the limb in many stars of the sample, and prominences viewed against the disk at some orbital phases in the dwarfs OU Gem and BF Lyn. The He i D3 line has been detected as an absorption feature in mainly all the giants of the sample. Total filling-in of the He i D3, probably due to microflaring activity, is observed in HU Vir. Self-absorption with red asymmetry is detected in the Ca II H & K lines of the giants 12 Cam, FG UMa and BM CVn. All the stars analysed show clear filled-in Ca II IRT lines or even notable emission reversal. The small values of the E_8542/E_8498 ratio we have found indicate Ca II IRT emission arises from plage-like regions. Orbital phase modulation of the chromospheric emission has been detected in some systems, in the case of HU Vir evidence of an active longitude area has been found. Based on observations made with the Isaac Newton Telescope (INT) operated on the island of La Palma by the Isaac Newton

  6. High-resolution inventory of technologies, activities, and emissions of coal-fired power plants in China from 1990 to 2010

    NASA Astrophysics Data System (ADS)

    Liu, F.; Zhang, Q.; Tong, D.; Zheng, B.; Li, M.; Huo, H.; He, K. B.

    2015-12-01

    This paper, which focuses on emissions from China's coal-fired power plants during 1990-2010, is the second in a series of papers that aims to develop a high-resolution emission inventory for China. This is the first time that emissions from China's coal-fired power plants were estimated at unit level for a 20-year period. This inventory is constructed from a unit-based database compiled in this study, named the China coal-fired Power plant Emissions Database (CPED), which includes detailed information on the technologies, activity data, operation situation, emission factors, and locations of individual units and supplements with aggregated data where unit-based information is not available. Between 1990 and 2010, compared to a 479 % growth in coal consumption, emissions from China's coal-fired power plants increased by 56, 335, and 442 % for SO2, NOx, and CO2, respectively, and decreased by 23 and 27 % for PM2.5 and PM10 respectively. Driven by the accelerated economic growth, large power plants were constructed throughout the country after 2000, resulting in a dramatic growth in emissions. The growth trend of emissions has been effectively curbed since 2005 due to strengthened emission control measures including the installation of flue gas desulfurization (FGD) systems and the optimization of the generation fleet mix by promoting large units and decommissioning small ones. Compared to previous emission inventories, CPED significantly improved the spatial resolution and temporal profile of the power plant emission inventory in China by extensive use of underlying data at unit level. The new inventory developed in this study will enable a close examination of temporal and spatial variations of power plant emissions in China and will help to improve the performances of chemical transport models by providing more accurate emission data.

  7. High-resolution inventory of technologies, activities, and emissions of coal-fired power plants in China from 1990 to 2010

    NASA Astrophysics Data System (ADS)

    Liu, F.; Zhang, Q.; Tong, D.; Zheng, B.; Li, M.; Huo, H.; He, K. B.

    2015-07-01

    This paper, which focuses on emissions from China's coal-fired power plants during 1990-2010, is the second in a series of papers that aims to develop high-resolution emission inventory for China. This is the first time that emissions from China's coal-fired power plants were estimated at unit level for a 20 year period. This inventory is constructed from a unit-based database compiled in this study, named the China coal-fired Power plant Emissions Database (CPED), which includes detailed information on the technologies, activity data, operation situation, emission factors, and locations of individual units and supplements with aggregated data where unit-based information is not available. Between 1990 and 2010, compared to a 479 % growth in coal consumption, emissions from China's coal-fired power plants increased by 56, 335 and 442 % for SO2, NOx and CO2, respectively, and decreased by 23 % for PM2.5. Driven by the accelerated economy growth, large power plants were constructed throughout the country after 2000, resulting in dramatic growth in emissions. Growth trend of emissions has been effective curbed since 2005 due to strengthened emission control measures including the installation of flue-gas desulfurization (FGD) systems and the optimization of the generation fleet mix by promoting large units and decommissioning small ones. Compared to previous emission inventories, CPED significantly improved the spatial resolution and temporal profile of power plant emission inventory in China by extensive use of underlying data at unit level. The new inventory developed in this study will enable a close examination for temporal and spatial variations of power plant emissions in China and will help to improve the performances of chemical transport models by providing more accurate emission data.

  8. Advanced very high resolution radiometer

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The advanced very high resolution radiometer development program is considered. The program covered the design, construction, and test of a breadboard model, engineering model, protoflight model, mechanical structural model, and a life test model. Special bench test and calibration equipment was also developed for use on the program.

  9. High resolution digital delay timer

    DOEpatents

    Martin, Albert D.

    1988-01-01

    Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay (20) provides a first output signal (24) at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits (26, 28) latch the high resolution data (24) to form a first synchronizing data set (60). A selected time interval has been preset to internal counters (142, 146, 154) and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses (32, 34) count down the counters to generate an internal pulse delayed by an interval which is functionally related to the preset time interval. A second LCD (184) corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD (74) to generate a second set of synchronizing data (76) which is complementary with the first set of synchronizing data (60) for presentation to logic circuits (64). The logic circuits (64) further delay the internal output signal (72) to obtain a proper phase relationship of an output signal (80) with the internal pulses (32, 34). The final delayed output signal (80) thereafter enables the output pulse generator (82) to produce the desired output pulse (84) at the preset time delay interval following input of the trigger pulse (10, 12).

  10. Shallow subsurface imaging of the Piano di Pezza active normal fault (central Italy) by high-resolution refraction and electrical resistivity tomography coupled with time domain electromagnetic data

    NASA Astrophysics Data System (ADS)

    Villani, Fabio; Tulliani, Valerio; Fierro, Elisa; Sapia, Vincenzo; Civico, Riccardo

    2015-04-01

    The Piano di Pezza fault is the north-westernmost segment of the >20 km long Ovindoli-Pezza active normal fault-system (central Italy). Although existing paleoseismic data document high vertical Holocene slip rates (~1 mm/yr) and a remarkable seismogenic potential of this fault, its subsurface setting and Pleistocene cumulative displacement are still poorly known. We investigated for the first time by means of high-resolution seismic and electrical resistivity tomography coupled with time domain electromagnetic (TDEM) measurements the shallow subsurface of a key section of the Piano di Pezza fault. Our surveys cross a ~5 m-high fault scarp that was generated by repeated surface-rupturing earthquakes displacing some Late Holocene alluvial fans. We provide 2-D Vp and resistivity images which clearly show significant details of the fault structure and the geometry of the shallow basin infill material down to 50 m depth. We can estimate the dip (~50°) and the Holocene vertical displacement of the master fault (~10 m). We also recognize in the hangingwall some low-velocity/low-resistivity regions that we relate to packages of colluvial wedges derived from scarp degradation, which may represent the record of several paleo-earthquakes older than the Late Holocene events previously recognized by paleoseismic trenching. Conversely, due to the limited investigation depth of seismic and electrical tomography, the estimation of the cumulative amount of Pleistocene throw is hampered. Therefore, to increase the depth of investigation, we performed 7 TDEM measurements along the electrical profile using a 50 m loop size both in central and offset configuration. The recovered 1-D resistivity models show a good match with 2-D resistivity images in the near surface. Moreover, TDEM inversion results indicate that in the hangingwall, ~200 m away from the surface fault trace, the carbonate pre-Quaternary basement may be found at ~90-100 m depth. The combined approach of electrical and

  11. Super-High-Resolution Seismic-Reflection-Based Analysis of the Late Pleistocene- Holocene Highstand-Active Newport Channel and Its Distributaries, Southern California Borderland

    NASA Astrophysics Data System (ADS)

    Temeng, A.; Covault, J. A.; Paull, C. K.; Ryan, H.; Sliter, R.; Graham, S. A.

    2008-12-01

    Super-high-resolution multibeam bathymetry (vertical resolution of 0.15-m and horizontal resolution of 1 m at 50 m survey altitude) and chirp seismic-reflection profiles (3.5 kHz; vertical resolution of 0.11 m) were collected by Monterey Bay Aquarium Research Institute's Autonomous Underwater Vehicle (AUV) in order to examine fine-scale details of the Holocene-active Newport channel and its distributaries offshore southern California. The resolution afforded by these data greatly exceeds industry-standard multichannel seismic- reflection data (typically 10 to 25 m vertical resolution). Recently acquired sparker data (100 to 4000 Hz), older Huntec deep-tow boomer (800 to 1200 Hz) and WesternGeco multichannel seismic-reflection data collected since the 1970's are available to analyze coarser-scale channel geometry and longer-term depositional evolution. As many as 48 radiocarbon ages from 16 piston cores are available in order to establish a chronostratigraphic framework for the latest Pleistocene and Holocene. Data show up to three coalescing, southwestward-trending, low-relief distributary channels at 800 m water depth in the western survey, whose features stand in sharp contrast with gentle, nearly flat topography in the eastern survey. The surveys are separated by the left-lateral Carlsbad Ridge Fault. Chirp profiles show the cut-and-fill organization of distributary channel-filling turbidites, which have an average thickness of ~ 2 m. Distributary channels are depressions < 1 km wide, with relief < 4 m from channel floor to levee top. The aim of this research is to study the stratigraphic architecture of these coalescing distributary channels and characterize their avulsion and depositional history and relationship to the main Newport channel. Additionally, the fine-scale stratigraphic architecture will be correlated with well-documented southern California allogenic influences of sedimentation, including climate, basin tectonics and sea level. This study

  12. High-resolution geophysical data collected offshore of Fire Island, New York in 2011, U.S. Geological Survey Field Activity 2011-005-FA.

    USGS Publications Warehouse

    Denny, Jane F.; Schwab, William C.; Baldwin, Wayne E.; Moore, Eric; Bergeron, Emile M.

    2015-01-01

    The U.S. Geological Survey (USGS) mapped approximately 336 square kilometers of the lower shoreface and inner-continental shelf offshore of Fire Island, New York in 2011 using interferometric sonar and high-resolution chirp seismic-reflection systems. These spatial data support research on the Quaternary evolution of the Fire Island coastal system and provide baseline information for research on coastal processes along southern Long Island.

  13. High-resolution simulations of atmospheric CO2 over complex terrain - representing the Ochsenkopf mountain tall tower

    NASA Astrophysics Data System (ADS)

    Pillai, D.; Gerbig, C.; Ahmadov, R.; Rödenbeck, C.; Kretschmer, R.; Koch, T.; Thompson, R.; Neininger, B.; Lavrié, J. V.

    2011-08-01

    Accurate simulation of the spatial and temporal variability of tracer mixing ratios over complex terrain is challenging, but essential in order to utilize measurements made in complex orography (e.g. mountain and coastal sites) in an atmospheric inverse framework to better estimate regional fluxes of these trace gases. This study investigates the ability of high-resolution modeling tools to simulate meteorological and CO2 fields around Ochsenkopf tall tower, situated in Fichtelgebirge mountain range- Germany (1022 m a.s.l.; 50°1'48" N, 11°48'30" E). We used tower measurements made at different heights for different seasons together with the measurements from an aircraft campaign. Two tracer transport models - WRF (Eulerian based) and STILT (Lagrangian based), both with a 2 km horizontal resolution - are used together with the satellite-based biospheric model VPRM to simulate the distribution of atmospheric CO2 concentration over Ochsenkopf. The results suggest that the high-resolution models can capture diurnal, seasonal and synoptic variability of observed mixing ratios much better than coarse global models. The effects of mesoscale transports such as mountain-valley circulations and mountain-wave activities on atmospheric CO2 distributions are reproduced remarkably well in the high-resolution models. With this study, we emphasize the potential of using high-resolution models in the context of inverse modeling frameworks to utilize measurements provided from mountain or complex terrain sites.

  14. High-resolution simulations of atmospheric CO2 over complex terrain - representing the Ochsenkopf mountain tall tower

    NASA Astrophysics Data System (ADS)

    Pillai, D.; Gerbig, C.; Ahmadov, R.; Rödenbeck, C.; Kretschmer, R.; Koch, T.; Thompson, R.; Neininger, B.; Lavrič, J. V.

    2011-03-01

    Accurate simulation of the spatial and temporal variability of tracer mixing ratios over complex terrain is challenging, but essential in order to utilize measurements made in complex orography (e.g. mountain and coastal sites) in an atmospheric inverse framework to better estimate regional fluxes of these trace gases. This study investigates the ability of high-resolution modeling tools to simulate meteorological and CO2 fields around Ochsenkopf tall tower, situated in Fichtelgebirge mountain range - Germany (1022 m a.s.l.; 50°1'48'' N, 11°48'30'' E). We used tower measurements made at different heights for different seasons together with the measurements from an aircraft campaign. Two tracer transport models - WRF (Eulerian based) and STILT (Lagrangian based), both with a 2 km horizontal resolution - are used together with the satellite-based biospheric model VPRM to simulate the distribution of atmospheric CO2 concentration over Ochsenkopf. The results suggest that the high-resolution models can capture diurnal, seasonal and synoptic variability of observed mixing ratios much better than coarse global models. The effects of mesoscale transports such as mountain-valley circulations and mountain-wave activities on atmospheric CO2 distributions are reproduced remarkably well in the high-resolution models. With this study, we emphasize the potential of using high-resolution models in the context of inverse modeling frameworks to utilize measurements provided from mountain or complex terrain sites.

  15. High-Resolution Intravital Microscopy

    PubMed Central

    Andresen, Volker; Pollok, Karolin; Rinnenthal, Jan-Leo; Oehme, Laura; Günther, Robert; Spiecker, Heinrich; Radbruch, Helena; Gerhard, Jenny; Sporbert, Anje; Cseresnyes, Zoltan; Hauser, Anja E.; Niesner, Raluca

    2012-01-01

    Cellular communication constitutes a fundamental mechanism of life, for instance by permitting transfer of information through synapses in the nervous system and by leading to activation of cells during the course of immune responses. Monitoring cell-cell interactions within living adult organisms is crucial in order to draw conclusions on their behavior with respect to the fate of cells, tissues and organs. Until now, there is no technology available that enables dynamic imaging deep within the tissue of living adult organisms at sub-cellular resolution, i.e. detection at the level of few protein molecules. Here we present a novel approach called multi-beam striped-illumination which applies for the first time the principle and advantages of structured-illumination, spatial modulation of the excitation pattern, to laser-scanning-microscopy. We use this approach in two-photon-microscopy - the most adequate optical deep-tissue imaging-technique. As compared to standard two-photon-microscopy, it achieves significant contrast enhancement and up to 3-fold improved axial resolution (optical sectioning) while photobleaching, photodamage and acquisition speed are similar. Its imaging depth is comparable to multifocal two-photon-microscopy and only slightly less than in standard single-beam two-photon-microscopy. Precisely, our studies within mouse lymph nodes demonstrated 216% improved axial and 23% improved lateral resolutions at a depth of 80 µm below the surface. Thus, we are for the first time able to visualize the dynamic interactions between B cells and immune complex deposits on follicular dendritic cells within germinal centers (GCs) of live mice. These interactions play a decisive role in the process of clonal selection, leading to affinity maturation of the humoral immune response. This novel high-resolution intravital microscopy method has a huge potential for numerous applications in neurosciences, immunology, cancer research and developmental biology

  16. High-resolution Visible Spectra of Titan

    NASA Astrophysics Data System (ADS)

    Sim, Chae Kyung; Kim, S.

    2006-09-01

    We have obtained high-resolution (R 30,000) spectra of Titan between 4,000 and 10,000 A on Feb. 23, 2005 (UT) using an optical echelle spectrograph (BOES) on the 1.8-m telescope at Bohyunsan Observatory, Korea. The raw Titan spectra contain telluric and solar absorption/emission lines. We used Kitt Peak solar atlases to remove the solar lines effectively. We also constructed synthetic spectra for the atmosphere of Titan including haze layers and utilizing laboratory spectra of CH4 available in literature. Preliminary results on the identifications of weak CH4 lines and on the derived opacities of the haze layers will be presented. Since the observations were carried out near the activities of Cassini observations of Titan, these high-resolution visible spectra are complementary to Cassini/VIMS imagery.

  17. High Resolution Scanning Reflectarray Antenna

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R. (Inventor); Miranda, Felix A. (Inventor)

    2000-01-01

    The present invention provides a High Resolution Scanning Reflectarray Antenna (HRSRA) for the purpose of tracking ground terminals and space craft communication applications. The present invention provides an alternative to using gimbaled parabolic dish antennas and direct radiating phased arrays. When compared to a gimbaled parabolic dish, the HRSRA offers the advantages of vibration free steering without incurring appreciable cost or prime power penalties. In addition, it offers full beam steering at a fraction of the cost of direct radiating arrays and is more efficient.

  18. High-Resolution Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Dozier, Jeff; Goetz, Alexander F. H.

    1990-01-01

    Earth resources observed in greater detail. High-Resolution Imaging Spectrometer, undergoing development for use in NASA's Earth Observing System, measures reflectance of Earth's surface in visible and near-infrared wavelengths. From an orbit around Earth, instrument scans surface of Earth in 200 wavelength bands simultaneously. Produces images enabling identification of minerals in rocks and soils, important algal pigments in oceans and inland waters, changes in spectra associated with biochemistry of plant canopies, compositions of atmospheric aerosols, sizes of grains in snow, and contamination of snow by impurities that absorb visible light.

  19. Perturbative path-integral study of active- and passive-tracer diffusion in fluctuating fields

    NASA Astrophysics Data System (ADS)

    Démery, Vincent; Dean, David S.

    2011-07-01

    We study the effective diffusion constant of a Brownian particle linearly coupled to a thermally fluctuating scalar field. We use a path-integral method to compute the effective diffusion coefficient perturbatively to lowest order in the coupling constant. This method can be applied to cases where the field is affected by the particle (an active tracer) and cases where the tracer is passive. Our results are applicable to a wide range of physical problems, from a protein diffusing in a membrane to the dispersion of a passive tracer in a random potential. In the case of passive diffusion in a scalar field, we show that the coupling to the field can, in some cases, speed up the diffusion corresponding to a form of stochastic resonance. Our results on passive diffusion are also confirmed via a perturbative calculation of the probability density function of the particle in a Fokker-Planck formulation of the problem. Numerical simulations on simplified systems corroborate our results.

  20. High-Resolution US of Rheumatologic Diseases.

    PubMed

    Taljanovic, Mihra S; Melville, David M; Gimber, Lana H; Scalcione, Luke R; Miller, Margaret D; Kwoh, C Kent; Klauser, Andrea S

    2015-01-01

    For the past 15 years, high-resolution ultrasonography (US) is being routinely and increasingly used for initial evaluation and treatment follow-up of rheumatologic diseases. This imaging technique is performed by using high-frequency linear transducers and has proved to be a powerful diagnostic tool in evaluation of articular erosions, simple and complex joint and bursal effusions, tendon sheath effusions, and synovitis, with results comparable to those of magnetic resonance imaging, excluding detection of bone marrow edema. Crystal deposition diseases including gouty arthropathy and calcium pyrophosphate deposition disease (CPPD) have characteristic appearances at US, enabling differentiation between these two diseases and from inflammatory arthropathies. Enthesopathy, which frequently accompanies psoriatic and reactive arthritis, also has a characteristic appearance at high-resolution US, distinguishing these two entities from other inflammatory and metabolic arthropathies. The presence of Doppler signal in examined joints, bursae, and tendon sheaths indicates active synovitis. Microbubble echo contrast agents augment detection of tissue vascularity and may act in the future as a drug delivery vehicle. Frequently, joint, tendon sheath, and bursal fluid aspirations and therapeutic injections are performed under US guidance. The authors describe the high-resolution US technique including gray-scale, color or power Doppler, and contrast agent-enhanced US that is used in evaluation of rheumatologic diseases of the wrist and hand and the ankle and foot in their routine clinical practice. This article demonstrates imaging findings of normal joints, rheumatoid arthritis, gouty arthritis, CPPD, psoriatic and reactive arthritis, and osteoarthritis. PMID:26562235

  1. The High Resolution Hurricane Test

    NASA Astrophysics Data System (ADS)

    Tripoli, G. J.

    2009-09-01

    It has been suggested that an answer to the hurricane intensity forecast problem is to use very high cloud-resolving resolution in operational forecast models. In consideration of this hypothesis, the United States National Atmospheric and Oceanic Administration commissioned a major study to take place over the past 1.5 years whereby the hypothesis would be tested with 6 different hurricane models featuring different dynamics cores and different physics. These models included the GFDL hurricane, Navy COAMPS, the WRF-ARW, WRF-AHW, WRF-NMM, and the UW-NMS. The experiment design was to choose and optimal mix of historic hurricanes where good observations of intensity at land fall existed and run 5 day model forecasts with 3 different resolutions of about 9-12 km (low resolution), 3-4 km (medium resolution) and 1-1.5 km (high resolution) and document how much the forecast improved in each case. The project focused on 10 storms over 2-12, 1-5 day forecast periods, for a total of 67 simulations. Not all groups completed all 67 simulations, but there were sufficient results to reach a stunning conclusion. The results of these tests suggested that little or no improvement in intensity prediction was achieved with high resolution.

  2. Tracking and evolution of irrigation triggered active landslides by multi-source high resolution DEM: The Jiaojiacun landslide group of Heifangtai (Northwest of China)

    NASA Astrophysics Data System (ADS)

    Zeng, Runqiang; Meng, Xingmin; Wang, Siyuan; Chen, Guan; Lee, Yajun; Zhang, Yi

    2014-05-01

    The construction of three large hydropower stations, i.e. Liujia, Yanguo and Bapan, resulted in the immigration of the impacted people to Heifangtai from 1960s. To support the living and farming of the immigrated people, a large amount of water has been pumped from the Yellow River to Heifangtai, which has changed the former underground water budget and led to 111 landslides from 1968 in this area. To reveal the deformation process of landslides in Heifangtai, a quantitative deformation analysis model of landslide based on multi-source DEM data is established using four periods of topographic maps obtained in 1970, 2001, 2010 and 2013 respectively, including two 1:10000 topographic maps and two 1:1000 data acquired from 3D Laser Scanner. The whole study area was divided into two sections based on the two distinct kinds of landslide patterns. The selected morphometric parameters, residual topographic surface and surface roughness, extracted from three typical landslides, and the statistical analysis (Box-plot diagrams) of the temporal variations of these parameters, allowed the reconstruction and tracking of these landslides. We monitored the changing of landslide boundaries, average vertical and horizontal displacement rates and zones of uplift and subsidence. The volumes of removed and/or accumulated material were estimated as well. We can then demonstrate the kinematics of landslides based on information from high-resolution DEM, and the changing table of underground water, ring-shear test and soil-water characteristic curve referenced from other researchers. The results provide a new insight on the use of multi-source high resolution DEM in the monitoring of irrigation-triggered landslides.

  3. High-resolution seismic stratigraphy of the late Neogene of the central sector of the Colombian Pacific continental shelf: A seismic expression of an active continental margin

    NASA Astrophysics Data System (ADS)

    Martínez, Jaime Orlando; López Ramos, Eduardo

    2011-02-01

    The sedimentary prism of the central Pacific continental shelf of Colombia was affected by regional folding and faulting, and probably later mud diapirism, from the Late Miocene to the Holocene. Interpretation of high-resolution seismic lines (2 s/dt) revealed that the prism consists of 13 high-resolution seismic units, that can be separated into 5 seismic groups. Deposition of the prism and the associated stacking pattern, are probably the response to variable uplift and subsidence in a fore-arc basin that underwent important tectonic events by the end of the Miocene. Throughout the Pliocene, the continental shelf sedimentation was affected by the growing of a dome structure probable due to mud diapirism. This fact caused peripheral faults both normal and reverse that controlled the distribution of some of the seismic units. During the Late Pleistocene (Wisconsin stage?) a eustatic sea level fall caused the shoreline to advance about 50 km westward of its present position. Because of this eustatic sea level change, a strong fluvial dissection took place and is interpreted as the probable extension of the San Juan River to the south of the present day river mouth. Within this framework it is believed that the Malaga and Buenaventura Bays were the passageways of branches of the old drainage system of the San Juan River. The inner branch circulated through the present Buenaventura Bay and runs southward leaving the mark of an apparent valley identified in the seismic information in the eastern sector of the study area. This old fluvial valley and its filling material located in the present day inner continental shelf front of Buenaventura are postulated as important targets to find placer minerals such as gold and platinum.

  4. Comparison of denitrification activity measurements in groundwater using cores and natural-gradient tracer tests

    USGS Publications Warehouse

    Smith, R.L.; Garabedian, S.P.; Brooks, M.H.

    1996-01-01

    The transport of many solutes in groundwater is dependent upon the relative rates of physical flow and microbial metabolism. Quantifying rates of microbial processes under subsurface conditions is difficult and is most commonly approximated using laboratory studies with aquifer materials. In this study, we measured in situ rates of denitrification in a nitrate- contaminated aquifer using small-scale, natural-gradient tracer tests and compared the results with rates obtained from laboratory incubations with aquifer core material. Activity was measured using the acetylene block technique. For the tracer tests, co-injection of acetylene and bromide into the aquifer produced a 30 ??M increase in nitrous oxide after 10 m of transport (23-30 days). An advection-dispersion transport model was modified to include an acetylene-dependent nitrous oxide production term and used to simulate the tracer breakthrough curves. The model required a 4-day lag period and a relatively low sensitivity to acetylene to match the narrow nitrous oxide breakthrough curves. Estimates of in situ denitrification rates were 0.60 and 1.51 nmol of N2O produced cm-3 aquifer day-1 for two successive tests. Aquifer core material collected from the tracer test site and incubated as mixed slurries in flasks and as intact cores yielded rates that were 1.2-26 times higher than the tracer test rate estimates. Results with the coring-dependent techniques were variable and subject to the small- scale heterogeneity within the aquifer, while the tracer tests integrated the heterogeneity along a flow path, giving a rate estimate that is more applicable to transport at the scale of the aquifer.

  5. Enhanced High Resolution RBS System

    SciTech Connect

    Pollock, Thomas J.; Hass, James A.; Klody, George M.

    2011-06-01

    Improvements in full spectrum resolution with the second NEC high resolution RBS system are summarized. Results for 50 A ring TiN/HfO films on Si yielding energy resolution on the order of 1 keV are also presented. Detector enhancements include improved pulse processing electronics, upgraded shielding for the MCP/RAE detector, and reduced noise generated from pumping. Energy resolution measurements on spectra front edge coupled with calculations using 0.4mStr solid angle show that beam energy spread at 400 KeV from the Pelletron registered accelerator is less than 100 eV. To improve user throughput, magnet control has been added to the automatic data collection. Depth profiles derived from experimental data are discussed. For the thin films profiled, depth resolutions were on the Angstrom level with the non-linear energy/channel conversions ranging from 100 to 200 eV.

  6. Enhanced High Resolution RBS System

    NASA Astrophysics Data System (ADS)

    Pollock, Thomas J.; Hass, James A.; Klody, George M.

    2011-06-01

    Improvements in full spectrum resolution with the second NEC high resolution RBS system are summarized. Results for 50 Å TiN/HfO films on Si yielding energy resolution on the order of 1 keV are also presented. Detector enhancements include improved pulse processing electronics, upgraded shielding for the MCP/RAE detector, and reduced noise generated from pumping. Energy resolution measurements on spectra front edge coupled with calculations using 0.4mStr solid angle show that beam energy spread at 400 KeV from the Pelletron® accelerator is less than 100 eV. To improve user throughput, magnet control has been added to the automatic data collection. Depth profiles derived from experimental data are discussed. For the thin films profiled, depth resolutions were on the Angstrom level with the non-linear energy/channel conversions ranging from 100 to 200 eV.

  7. High Resolution Thermometry for EXACT

    NASA Technical Reports Server (NTRS)

    Panek, J. S.; Nash, A. E.; Larson, M.; Mulders, N.

    2000-01-01

    High Resolution Thermometers (HRTs) based on SQUID detection of the magnetization of a paramagnetic salt or a metal alloy has been commonly used for sub-nano Kelvin temperature resolution in low temperature physics experiments. The main applications to date have been for temperature ranges near the lambda point of He-4 (2.177 K). These thermometers made use of materials such as Cu(NH4)2Br4 *2H2O, GdCl3, or PdFe. None of these materials are suitable for EXACT, which will explore the region of the He-3/He-4 tricritical point at 0.87 K. The experiment requirements and properties of several candidate paramagnetic materials will be presented, as well as preliminary test results.

  8. High Resolution Neutral Atom Microscope

    NASA Astrophysics Data System (ADS)

    Bucay, Igal; Castillo-Garza, Rodrigo; Stratis, Georgios; Raizen, Mark

    2015-03-01

    We are developing a high resolution neutral atom microscope based on metastable atom electron spectroscopy (MAES). When a metastable atom of a noble gas is near a solid, a surface electron will tunnel to an empty energy level of the metastable atom, thereby ejecting the excited electron from the atom. The emitted electrons carry information regarding the local topography and electronic, magnetic, and chemical structures of most hard materials. Furthermore, using a chromatic aberration corrected magnetic hexapole lens we expect to attain a spatial resolution below 10 nm. We will use this microscope to investigate how local phenomena can give rise to macroscopic effects in materials that cannot be probed using a scanning tunneling microscope, namely insulating transition metal oxides.

  9. High Resolution Stereo Camera (HRSC) on Mars Express - a decade of PR/EO activities at Freie Universität Berlin

    NASA Astrophysics Data System (ADS)

    Balthasar, Heike; Dumke, Alexander; van Gasselt, Stephan; Gross, Christoph; Michael, Gregory; Musiol, Stefanie; Neu, Dominik; Platz, Thomas; Rosenberg, Heike; Schreiner, Björn; Walter, Sebastian

    2014-05-01

    Since 2003 the High Resolution Stereo Camera (HRSC) experiment on the Mars Express mission is in orbit around Mars. First images were sent to Earth on January 14th, 2004. The goal-oriented HRSC data dissemination and the transparent representation of the associated work and results are the main aspects that contributed to the success in the public perception of the experiment. The Planetary Sciences and Remote Sensing Group at Freie Universität Berlin (FUB) offers both, an interactive web based data access, and browse/download options for HRSC press products [www.fu-berlin.de/planets]. Close collaborations with exhibitors as well as print and digital media representatives allows for regular and directed dissemination of, e.g., conventional imagery, orbital/synthetic surface epipolar images, video footage, and high-resolution displays. On a monthly basis we prepare press releases in close collaboration with the European Space Agency (ESA) and the German Aerospace Center (DLR) [http://www.geo.fu-berlin.de/en/geol/fachrichtungen/planet/press/index.html]. A release comprises panchromatic, colour, anaglyph, and perspective views of a scene taken from an HRSC image of the Martian surface. In addition, a context map and descriptive texts in English and German are provided. More sophisticated press releases include elaborate animations and simulated flights over the Martian surface, perspective views of stereo data combined with colour and high resolution, mosaics, and perspective views of data mosaics. Altogether 970 high quality PR products and 15 movies were created at FUB during the last decade and published via FUB/DLR/ESA platforms. We support educational outreach events, as well as permanent and special exhibitions. Examples for that are the yearly "Science Fair", where special programs for kids are offered, and the exhibition "Mars Mission and Vision" which is on tour until 2015 through 20 German towns, showing 3-D movies, surface models, and images of the HRSC

  10. High resolution tomographic instrument development

    SciTech Connect

    Not Available

    1992-08-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  11. High resolution tomographic instrument development

    SciTech Connect

    Not Available

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  12. HRSC: High resolution stereo camera

    USGS Publications Warehouse

    Neukum, G.; Jaumann, R.; Basilevsky, A.T.; Dumke, A.; Van Gasselt, S.; Giese, B.; Hauber, E.; Head, J. W., III; Heipke, C.; Hoekzema, N.; Hoffmann, H.; Greeley, R.; Gwinner, K.; Kirk, R.; Markiewicz, W.; McCord, T.B.; Michael, G.; Muller, Jan-Peter; Murray, J.B.; Oberst, J.; Pinet, P.; Pischel, R.; Roatsch, T.; Scholten, F.; Willner, K.

    2009-01-01

    The High Resolution Stereo Camera (HRSC) on Mars Express has delivered a wealth of image data, amounting to over 2.5 TB from the start of the mapping phase in January 2004 to September 2008. In that time, more than a third of Mars was covered at a resolution of 10-20 m/pixel in stereo and colour. After five years in orbit, HRSC is still in excellent shape, and it could continue to operate for many more years. HRSC has proven its ability to close the gap between the low-resolution Viking image data and the high-resolution Mars Orbiter Camera images, leading to a global picture of the geological evolution of Mars that is now much clearer than ever before. Derived highest-resolution terrain model data have closed major gaps and provided an unprecedented insight into the shape of the surface, which is paramount not only for surface analysis and geological interpretation, but also for combination with and analysis of data from other instruments, as well as in planning for future missions. This chapter presents the scientific output from data analysis and highlevel data processing, complemented by a summary of how the experiment is conducted by the HRSC team members working in geoscience, atmospheric science, photogrammetry and spectrophotometry. Many of these contributions have been or will be published in peer-reviewed journals and special issues. They form a cross-section of the scientific output, either by summarising the new geoscientific picture of Mars provided by HRSC or by detailing some of the topics of data analysis concerning photogrammetry, cartography and spectral data analysis.

  13. High resolution tomographic instrument development

    NASA Astrophysics Data System (ADS)

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefitted greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  14. High-resolution magnetic signature of active hydrothermal systems in the back-arc spreading region of the southern Mariana Trough

    NASA Astrophysics Data System (ADS)

    Fujii, Masakazu; Okino, Kyoko; Honsho, Chie; Dyment, Jerome; Szitkar, Florent; Mochizuki, Nobutatsu; Asada, Miho

    2015-05-01

    High-resolution vector magnetic measurements were performed on five hydrothermal vent fields of the back-arc spreading region of the southern Mariana Trough using Shinkai 6500, a deep-sea manned submersible. A new 3-D forward scheme was applied that exploits the surrounding bathymetry and varying altitudes of the submersible to estimate absolute crustal magnetization. The results revealed that magnetic-anomaly-derived absolute magnetizations show a reasonable correlation with natural remanent magnetizations of rock samples collected from the seafloor of the same region. The distribution of magnetic-anomaly-derived absolute magnetization suggests that all five andesite-hosted hydrothermal fields are associated with a lack of magnetization, as is generally observed at basalt-hosted hydrothermal sites. Furthermore, both the Pika and Urashima sites were found to have their own distinct low-magnetization zones, which could not be distinguished in magnetic anomaly data collected at higher altitudes by autonomous underwater vehicle due to their limited extension. The spatial extent of the resulting low magnetization is approximately 10 times wider at off-axis sites than at on-axis sites, possibly reflecting larger accumulations of nonmagnetic sulfides, stockwork zones, and/or alteration zones at the off-axis sites.

  15. Innovative radar products for the 3D, high-resolution and real-time monitoring of the convective activity in the airspace around airports

    NASA Astrophysics Data System (ADS)

    Tabary, P.; Bousquet, O.; Sénési, S.; Josse, P.

    2009-09-01

    Airports are recognized to become critical areas in the future given the expected doubling in air traffic by 2020. The increased density of aircrafts in the airport airspaces calls for improved systems and products to monitor in real-time potential hazards and thus meet the airport objectives in terms of safety and throughput. Among all meteorological hazards, convection is certainly the most impacting one. We describe here some innovative radar products that have recently been developed and tested at Météo France around the Paris airports. Those products rely on the French Doppler radar network consisting today of 24 elements with some of them being polarimetric. Reflectivity and Doppler volumetric data are concentrated from all 24 radar sites in real-time at the central level (Toulouse) where 3D Cartesian mosaics covering the entire French territory (i.e. a typical 1,000 by 1,000 km² area) are elaborated. The innovation with respect to what has been done previously is that the three components of the wind are retrieved by operational combination of the radial velocities. The final product, available in real-time every 15 minutes with a spatial resolution of 2.5 km horizontally and 500 m vertically, is a 3D grid giving the interpolated reflectivity and wind field (u, v and w) values. The 2.5 km resolution, arising from the fact that the retrieval is carried out every 15 minutes from radars typically spaced apart by 150 km, is not sufficient for airport airspace monitoring but is valuable for en-route monitoring. Its extension to the entire European space is foreseen. To address the specific needs in the airport areas, a downscaling technique has been proposed to merge the above-mentioned low-resolution 3D wind and reflectivity fields with the high resolution (5 minutes and 1 km²) 2D imagery of the Trappes radar that is the one that covers the Paris airports. The merging approach is based on the assumption that the Vertical Profile of Reflectivity (i.e. the

  16. The high resolution topographic evolution of an active retrogressive thaw slump compiled from a decade of photography, ground surveys, laser scans and satellite imagery

    NASA Astrophysics Data System (ADS)

    Crosby, B. T.; Barnhart, T. B.; Rowland, J. C.

    2015-12-01

    Remote sensing imagery has enables the temporal reconstruction of thermal erosion features including lakes, shorelines and hillslope failures in remote Arctic locations, yet these planar data limit analysis to lines and areas. This study explores the application of varying techniques to reconstruct the three dimensional evolution of a single thermal erosion feature using a mixture of opportunistic oblique photos, ground surveys and satellite imagery. At the Selawik River retrogressive thaw slump in northwest Alaska, a bush plane collected oblique aerial photos when the feature was first discovered in 2004 and in subsequent years. These images were recently processed via Structure from Motion to generate georeferenced point clouds for the years prior to the initiation of our research. High resolution ground surveys in 2007, 2009 and 2010 were completed using robotic total station. Terrestrial laser scans (TLS) were collected in the summers of 2011 and 2012. Analysis of stereo satellite imagery from 2012 and 2015 enable continued monitoring of the feature after ground campaigns ended. As accurate coregistraion between point clouds is vital to topographic change detection, all prior and subsequent datasets were georeferenced to stable features observed in the 2012 TLS scan. Though this coregistration introduces uncertainty into each image, the magnitudes of uncertainty are significantly smaller than the topographic changes detected. Upslope retreat of the slump headwall generally decreases over time as the slump floor progresses from a highly dissected gully topography to a low relief, earthflow dominated depositional plane. The decreasing slope of the slump floor diminishes transport capacity, resulting in the progressive burial of the slump headwall, thus decreasing headwall retreat rates. This self-regulation of slump size based on feature relief and transport capacity suggests a capacity to predict the maximum size a given feature can expand to before

  17. High resolution time interval counter

    DOEpatents

    Condreva, Kenneth J.

    1994-01-01

    A high resolution counter circuit measures the time interval between the occurrence of an initial and a subsequent electrical pulse to two nanoseconds resolution using an eight megahertz clock. The circuit includes a main counter for receiving electrical pulses and generating a binary word--a measure of the number of eight megahertz clock pulses occurring between the signals. A pair of first and second pulse stretchers receive the signal and generate a pair of output signals whose widths are approximately sixty-four times the time between the receipt of the signals by the respective pulse stretchers and the receipt by the respective pulse stretchers of a second subsequent clock pulse. Output signals are thereafter supplied to a pair of start and stop counters operable to generate a pair of binary output words representative of the measure of the width of the pulses to a resolution of two nanoseconds. Errors associated with the pulse stretchers are corrected by providing calibration data to both stretcher circuits, and recording start and stop counter values. Stretched initial and subsequent signals are combined with autocalibration data and supplied to an arithmetic logic unit to determine the time interval in nanoseconds between the pair of electrical pulses being measured.

  18. High resolution time interval counter

    DOEpatents

    Condreva, K.J.

    1994-07-26

    A high resolution counter circuit measures the time interval between the occurrence of an initial and a subsequent electrical pulse to two nanoseconds resolution using an eight megahertz clock. The circuit includes a main counter for receiving electrical pulses and generating a binary word--a measure of the number of eight megahertz clock pulses occurring between the signals. A pair of first and second pulse stretchers receive the signal and generate a pair of output signals whose widths are approximately sixty-four times the time between the receipt of the signals by the respective pulse stretchers and the receipt by the respective pulse stretchers of a second subsequent clock pulse. Output signals are thereafter supplied to a pair of start and stop counters operable to generate a pair of binary output words representative of the measure of the width of the pulses to a resolution of two nanoseconds. Errors associated with the pulse stretchers are corrected by providing calibration data to both stretcher circuits, and recording start and stop counter values. Stretched initial and subsequent signals are combined with autocalibration data and supplied to an arithmetic logic unit to determine the time interval in nanoseconds between the pair of electrical pulses being measured. 3 figs.

  19. High resolution optoelectronic retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Loudin, Jim; Dinyari, Rostam; Huie, Phil; Butterwick, Alex; Peumans, Peter; Palanker, Daniel

    2009-02-01

    Electronic retinal prostheses seek to restore sight in patients with retinal degeneration by delivering pulsed electric currents to retinal neurons via an array of microelectrodes. Most implants use inductive or optical transmission of information and power to an intraocular receiver, with decoded signals subsequently distributed to retinal electrodes through an intraocular cable. Surgical complexity could be minimized by an "integrated" prosthesis, in which both power and data are delivered directly to the stimulating array without any discrete components or cables. We present here an integrated retinal prosthesis system based on a photodiode array implant. Video frames are processed and imaged onto the retinal implant by a video goggle projection system operating at near-infrared wavelengths (~ 900 nm). Photodiodes convert light into pulsed electric current, with charge injection maximized by specially optimized series photodiode circuits. Prostheses of three different pixel densities (16 pix/mm2, 64 pix/mm2, and 256 pix/mm2) have been designed, simulated, and prototyped. Retinal tissue response to subretinal implants made of various materials has been investigated in RCS rats. The resulting prosthesis can provide sufficient charge injection for high resolution retinal stimulation without the need for implantation of any bulky discrete elements such as coils or tethers. In addition, since every pixel functions independently, pixel arrays may be placed separately in the subretinal space, providing visual stimulation to a larger field of view.

  20. High resolution auditory perception system

    NASA Astrophysics Data System (ADS)

    Alam, Iftekhar; Ghatol, Ashok

    2005-04-01

    Blindness is a sensory disability which is difficult to treat but can to some extent be helped by artificial aids. The paper describes the design aspects of a high resolution auditory perception system, which is designed on the principle of air sonar with binaural perception. This system is a vision substitution aid for enabling blind persons. The blind person wears ultrasonic eyeglasses which has ultrasonic sensor array embedded on it. The system has been designed to operate in multiresolution modes. The ultrasonic sound from the transmitter array is reflected back by the objects, falling in the beam of the array and is received. The received signal is converted to a sound signal, which is presented stereophonically for auditory perception. A detailed study has been done as the background work required for the system implementation; the appropriate range analysis procedure, analysis of space-time signals, the acoustic sensors study, amplification methods and study of the removal of noise using filters. Finally the system implementation including both the hardware and the software part of it has been described. Experimental results on actual blind subjects and inferences obtained during the study have also been included.

  1. High-Resolution Mass Spectrometers

    NASA Astrophysics Data System (ADS)

    Marshall, Alan G.; Hendrickson, Christopher L.

    2008-07-01

    Over the past decade, mass spectrometry has been revolutionized by access to instruments of increasingly high mass-resolving power. For small molecules up to ˜400 Da (e.g., drugs, metabolites, and various natural organic mixtures ranging from foods to petroleum), it is possible to determine elemental compositions (CcHhNnOoSsPp…) of thousands of chemical components simultaneously from accurate mass measurements (the same can be done up to 1000 Da if additional information is included). At higher mass, it becomes possible to identify proteins (including posttranslational modifications) from proteolytic peptides, as well as lipids, glycoconjugates, and other biological components. At even higher mass (˜100,000 Da or higher), it is possible to characterize posttranslational modifications of intact proteins and to map the binding surfaces of large biomolecule complexes. Here we review the principles and techniques of the highest-resolution analytical mass spectrometers (time-of-flight and Fourier transform ion cyclotron resonance and orbitrap mass analyzers) and describe some representative high-resolution applications.

  2. High-resolution slug testing.

    PubMed

    Zemansky, G M; McElwee, C D

    2005-01-01

    The hydraulic conductivity (K) variation has important ramifications for ground water flow and the transport of contaminants in ground water. The delineation of the nature of that variation can be critical to complete characterization of a site and the planning of effective and efficient remedial measures. Site-specific features (such as high-conductivity zones) need to be quantified. Our alluvial field site in the Kansas River valley exhibits spatial variability, very high conductivities, and nonlinear behavior for slug tests in the sand and gravel aquifer. High-resolution, multilevel slug tests have been performed in a number of wells that are fully screened. A general nonlinear model based on the Navier-Stokes equation, nonlinear frictional loss, non-Darcian flow, acceleration effects, radius changes in the wellbore, and a Hvorslev model for the aquifer has been used to analyze the data, employing an automated processing system that runs within the Excel spreadsheet program. It is concluded that slug tests can provide the necessary data to identify the nature of both horizontal and vertical K variation in an aquifer and that improved delineation or higher resolution of K structure is possible with shorter test intervals. The gradation into zones of higher conductivity is sharper than seen previously, and the maximum conductivity observed is greater than previously measured. However, data from this project indicate that well development, the presence of fines, and the antecedent history of the well are important interrelated factors in regard to slug-test response and can prevent obtaining consistent results in some cases. PMID:15819943

  3. Global high resolution climate reconstructions

    NASA Astrophysics Data System (ADS)

    Schubert-Frisius, Martina; Feser, Frauke; Zahn, Matthias; von Storch, Hans; Rast, Sebastian

    2014-05-01

    Long-term reanalysis products represent an important data source for numerous climate studies. However, their coarse spatial resolution for data sets spanning the last more than 50 years and well known inhomogeneities in space and time make it difficult to derive changes in meteorological variables over time. We therefore use spectral nudging technique to down-scale the global reanalysis data to a finer resolution with a general global circulation model. With this technique the new calculated higher resolved global model fields are attracted to the large-scale state of the coarse resolution reanalysis. Besides the conservation of large-scale atmospheric information and the resulting finer topography, a surplus in contents of information in meteorological phenomena of small spatial extensions is expected. Following this strategy a simulation with the global high-resolution atmospheric model ECHAM6 (T255L95), developed by MPI-M Hamburg, will be started by spectrally nudging NCEP1 reanalysis for the time period from 1948 until 2013. Selected wavelengths of more than 1000 km of vorticity, divergence, temperature and the logarithm of the surface pressure will be imposed onto the simulated GCM counterparts at levels above 750 hPa. SST and sea ice distribution are taken from the NCEP1 data set. These simulations enable the investigation of long-term changes in meteorological phenomena; the focus is put here on intense storms. Various horizontal wavelength selections and associated vertical profiles in the strength of nudging were tested. The temporarily best configuration resulted in large time correlations for 2m-temperature and 10m wind speed at several selected locations in Germany in comparison to observations. Correlations were highest for extra-tropical regions, while over the western part of the Pacific and Indian Ocean relative low time correlations were found. In a continuing study meteorological quantities at different levels and the influences of the nudging

  4. Practising high-resolution anoscopy.

    PubMed

    Palefsky, Joel M

    2012-12-01

    The incidence of anal cancer is increasing in the general population among both men and women. The incidence is particularly high among men who have sex with men and HIV-infected men and women. Anal cancer is similar to cervical cancer and is associated with human papillomavirus (HPV). Anal cancer is potentially preventable through primary prevention with HPV vaccination or secondary prevention. Secondary prevention is modelled after cervical cancer, where cytology is used as a screening tool to identify women who need colposcopy. Colposcopy includes magnification of the cervix, which, along with acetic acid and Lugol's solution, is used to visualise and biopsy potentially precancerous lesions, enabling treatment before progression to cervical cancer. Anal cancer is likely preceded by high-grade anal intraepithelial neoplasia (HGAIN), and a colposcope with acetic acid and Lugol's solution may similarly be used to visualise HGAIN to permit biopsy and treatment in an effort to prevent anal cancer. To distinguish it from cervical colposcopy, this technique is called high-resolution anoscopy (HRA). Many of the features that distinguish low-grade AIN from HGAIN are similar to those of the cervix, but HRA poses several additional challenges compared with cervical colposcopy. These include uneven topography; obscuring of lesions due to haemorrhoids, folds, stool or mucus; or lesions being located at the base of folds and anal glands. Consequently, a long learning curve is typically required before becoming fully competent in this technique. The technique of HRA, its uses and challenges in prevention of anal cancer are described in this article. PMID:23380236

  5. High Resolution Spectroscopy to Support Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Benner, D. Chris; Venkataraman, Malathy Devi

    2000-01-01

    The major research activities performed during the cooperative agreement enhanced our spectroscopic knowledge of molecules of atmospheric interest such as carbon dioxide, water vapor, ozone, methane, and carbon monoxide, to name a few. Measurements were made using the NASA Langley Tunable Diode Laser Spectrometer System (TDL) and several Fourier Transform Spectrometer Systems (FTS) around the globe. The results from these studies made remarkable improvements in the line positions and intensities for several molecules, particularly ozone and carbon dioxide in the 2 to 17-micrometer spectral region. Measurements of pressure broadening and pressure induced line shift coefficients and the temperature dependence of pressure broadening and pressure induced line shift coefficients for infrared transitions of ozone, methane, and water vapor were also performed. Results from these studies have been used for retrievals of stratospheric gas concentration profiles from data collected by several Upper Atmospheric Research satellite (UARS) infrared instruments as well as in the analysis of high resolution atmospheric spectra such as those acquired by space-based, ground-based, and various balloon- and aircraft-borne experiments. Our results made significant contributions in several updates of the HITRAN (HIgh resolution TRANsmission) spectral line parameters database. This database enjoys worldwide recognition in research involving diversified scientific fields.

  6. High Resolution Spectroscopy to Support Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Benner, D. Chris; Venkataraman, Malathy Devi

    2000-01-01

    The major research activities performed during the cooperative agreement enhanced our spectroscopic knowledge of molecules of atmospheric interest such as carbon dioxide, water vapor, ozone, methane, and carbon monoxide, to name a few. Measurements were made using the NASA Langley Tunable Diode Laser Spectrometer System (TDL) and several Fourier Transform Spectrometer Systems (FTS) around the globe. The results from these studies made remarkable improvements in the line positions and intensities for several molecules, particularly ozone and carbon dioxide in the 2 to 17-micrometer spectral region. Measurements of pressure broadening and pressure induced line shift coefficients and the temperature dependence of pressure broadening and pressure induced line shift coefficients for infrared transitions of ozone, methane, and water vapor were also performed. Results from these studies have been used for retrievals of stratospheric gas concentration profiles from data collected by several Upper Atmospheric Research satellite (UARS) infrared instruments as well as in the analysis of high resolution atmospheric spectra such as those acquired by space-based, ground-based, and various balloon-and aircraft-borne experiments. Our results made significant contributions in several updates of the HITRAN (HIgh resolution TRANsmission) spectral line parameters database. This database enjoys worldwide recognition in research involving diversified scientific fields.

  7. Hydraulic characterization of an activated sludge reactor with recycling system by tracer experiment and analytical models.

    PubMed

    Sánchez, F; Viedma, A; Kaiser, A S

    2016-09-15

    Fluid dynamic behaviour plays an important role in wastewater treatment. An efficient treatment requires the inexistence of certain hydraulic problems such as dead zones or short-circuiting flows. Residence time distribution (RTD) analysis is an excellent technique for detecting these inefficiencies. However, many wastewater treatment installations include water or sludge recycling systems, which prevent us from carrying out a conventional tracer pulse experiment to obtain the RTD curve of the installation. This paper develops an RTD analysis of an activated sludge reactor with recycling system. A tracer experiment in the reactor is carried out. Three analytical models, derived from the conventional pulse model, are proposed to obtain the RTD curve of the reactor. An analysis of the results is made, studying which model is the most suitable for each situation. This paper is useful to analyse the hydraulic efficiency of reactors with recycling systems. PMID:27288672

  8. Continuous, high-resolution biospeckle imaging reveals a discrete zone of activity at the root apex that responds to contact with obstacles

    PubMed Central

    Ribeiro, K. M.; Barreto, B.; Pasqual, M.; White, P. J.; Braga, R. A.; Dupuy, L. X.

    2014-01-01

    Background and Aims Shining a laser onto biological material produces light speckles termed biospeckles. Patterns of biospeckle activity reflect changes in cell biochemistry, developmental processes and responses to the environment. The aim of this work was to develop methods to investigate the biospeckle activity in roots and to characterize the distribution of its intensity and response to thigmostimuli. Methods Biospeckle activity in roots of Zea mays, and also Jatropha curcas and Citrus limonia, was imaged live and in situ using a portable laser and a digital microscope with a spatial resolution of 10 μm per pixel and the ability to capture images every 0·080 s. A procedure incorporating a Fujii algorithm, image restoration using median and Gaussian filters, image segmentation using maximum-entropy threshold methods and the extraction of features using a tracing algorithm followed by spline fitting were developed to obtain quantitative information from images of biospeckle activity. A wavelet transform algorithm was used for spectral decomposition of biospeckle activity and generalized additive models were used to attribute statistical significance to changes in patterns of biospeckle activity. Key Results The intensity of biospeckle activity was greatest close to the root apex. Higher frequencies (3–6 Hz) contributed most to the total intensity of biospeckle activity. When a root encountered an obstacle, the intensity of biospeckle activity decreased abruptly throughout the root system. The response became attenuated with repeated thigmostimuli. Conclusions The data suggest that at least one component of root biospeckle activity resulted from a biological process, which is located in the zone of cell division and responds to thigmostimuli. However, neither individual cell division events nor root elongation is likely to be responsible for the patterns of biospeckle activity. PMID:24284818

  9. Perturbative path-integral study of active- and passive-tracer diffusion in fluctuating fields.

    PubMed

    Démery, Vincent; Dean, David S

    2011-07-01

    We study the effective diffusion constant of a Brownian particle linearly coupled to a thermally fluctuating scalar field. We use a path-integral method to compute the effective diffusion coefficient perturbatively to lowest order in the coupling constant. This method can be applied to cases where the field is affected by the particle (an active tracer) and cases where the tracer is passive. Our results are applicable to a wide range of physical problems, from a protein diffusing in a membrane to the dispersion of a passive tracer in a random potential. In the case of passive diffusion in a scalar field, we show that the coupling to the field can, in some cases, speed up the diffusion corresponding to a form of stochastic resonance. Our results on passive diffusion are also confirmed via a perturbative calculation of the probability density function of the particle in a Fokker-Planck formulation of the problem. Numerical simulations on simplified systems corroborate our results. PMID:21867153

  10. Active thermal tracer testing in a shallow aquifer of the Thur valley, Switzerland

    NASA Astrophysics Data System (ADS)

    Schweingruber, Mischa; Somogyvári, Márk; Bayer, Peter

    2015-04-01

    Tracer tests are one of the standard methods for investigating groundwater processes. Among the range of different test variants, using heat as a tracer has gained substantial interest during the last decade. Temperature measurements have become essential ingredients for example for characterization of river-aquifer interactions and in the field of geothermics. Much less attention than on natural temperature signals has been devoted to induced synthetic temperature signals, even though it is well known that temperature is an easy to measure, invisible but sensitive system property. Design, application and inversion of such active thermal tracer tests represent one focus of our work. We build up on the experience from related field experiments, where heated water was injected and the propagation of the generated thermal anomaly was monitored. In this presentation, we show the results from first field-testing in an alluvial aquifer at the Widen site in the Thur valley in Switzerland. The thermal evolution of groundwater was monitored in summer 2014 during and after several days of heated water injection. By this test, we want to derive insights into the prevailing hydraulic heterogeneity of the shallow aquifer at the site. The results are used for calibration of a two dimensional hydrogeological numerical model. With the calibrated hydraulic conductivity field, the experiment is simulated and the transient evolution of the heat plume is visualized. Hydraulic heterogeneity is identified as one main factor for lateral spreading of the heat plume. The most important result of the experiment is that the significance of the ambient flow field is very high and even with high pumping rates to establish forced gradient conditions its effect cannot be overridden. During the test, precious technical experience was gained, which will be beneficial for subsequent heat tracer applications. For example, the challenge of maintaining a constant injection rate and temperature could

  11. Online coupling of high-resolution chromatography with extreme UV photon activation tandem mass spectrometry: Application to the structural investigation of complex glycans by dissociative photoionization.

    PubMed

    Ropartz, David; Giuliani, Alexandre; Fanuel, Mathieu; Hervé, Cécile; Czjzek, Mirjam; Rogniaux, Hélène

    2016-08-24

    The activation of ions by extreme-energy photons (XUV) produced by a synchrotron radiation beamline is a powerful method for characterizing complex glycans using tandem mass spectrometry (MS). As previously described, this activation method leads to rich fragmentation spectra with many structurally valuable cross-ring cleavages while maintaining labile modifications on the glycan structures. However, until now, the tandem MS event was too long to be compatible with liquid chromatography elution times. In this work, the duty cycle of the activation and detection of fragments was shortened, and the background signal on the spectra was drastically reduced. Both improvements allowed, for the first time, the successful coupling of a UHPLC system to XUV-activated tandem MS. The approach was used to characterize a complex mixture of oligo-porphyrans, which are a class of highly sulfated oligosaccharides, in a fully automated way. Due to an enhanced dynamic range and an increased sensitivity, some hypothetical structures of low abundance have been unequivocally confirmed in this study and others have been revised. Some previously undescribed species of oligo-porphyrans that exhibit lateral branching have been fully resolved. This work contributes to the scarce knowledge of the structure of porphyrans in red algae and pushes the current capacities of XUV-activation tandem MS by demonstrating the possibility of a direct coupling with UHPLC. This study will considerably broaden the applicability and practicality of this method in many fields of analytical biology. PMID:27496992

  12. Active Faulting, Earthquakes and Geomorphological Changes from Archaeoseismic Data and High-Resolution Topography: Effects on the Urban Evolution of the Roman Town of Sybaris, Ionian Sea (Southern Italy).

    NASA Astrophysics Data System (ADS)

    Alfonsi, L.; Brunori, C. A.; Cinti, F. R.

    2014-12-01

    The Sybaris town was founded by the Greeks in 720 B.C and its life went on up to the late Roman time (VI-VII century A.D.). The town was located within the Sibari Plain near the Crati River mouth (Ionian northern Calabria, southern Italy). Sybaris occurs in area repeatedly affected by natural damaging phenomena, as frequent flooding, high local subsidence, marine storms, and earthquakes. The 2700 year long record of history of Sybaris stores the traces of these natural events and their influence on the human ancient environment through time. Among the natural disasters, we recognize two Roman age earthquakes striking the town. We isolate the damaging of these seismic events, set their time of occurrence, and map a shear zone crossing the site. These results were obtained through i) survey of coseismic features on the ruins, ii) geoarchaeological stratigraphy analysis, and TL and C14 dating, iii) analysis of high-resolution topographic data (1m pixel LiDAR DEM). The Sybaris town showed a persistent resilience to the earthquakes, and following their occurrences the site was not abandoned but underwent remodeling of the urban topography. The interaction of the different approaches reveals the presence of a previously unknown fault crossing the archeological site, the Sybaris fault. The high-resolution topography allows the characterization of subtle geomorphological features and hydrological anomalies, tracing the fault extension, whose Holocene activity is controlling the local morphology and the present Crati river course.

  13. Detecting young, slow-slipping active faults by geologic and multidisciplinary high-resolution geophysical investigations: A case study from the Apennine seismic belt, Italy

    NASA Astrophysics Data System (ADS)

    Improta, L.; Ferranti, L.; de Martini, P. M.; Piscitelli, S.; Bruno, P. P.; Burrato, P.; Civico, R.; Giocoli, A.; Iorio, M.; D'Addezio, G.; Maschio, L.

    2010-11-01

    The Southern Apennines range of Italy presents significant challenges for active fault detection due to the complex structural setting inherited from previous contractional tectonics, coupled to very recent (Middle Pleistocene) onset and slow slip rates of active normal faults. As shown by the Irpinia Fault, source of a M6.9 earthquake in 1980, major faults might have small cumulative deformation and subtle geomorphic expression. A multidisciplinary study including morphological-tectonic, paleoseismological, and geophysical investigations has been carried out across the extensional Monte Aquila Fault, a poorly known structure that, similarly to the Irpinia Fault, runs across a ridge and is weakly expressed at the surface by small scarps/warps. The joint application of shallow reflection profiling, seismic and electrical resistivity tomography, and physical logging of cored sediments has proved crucial for proper fault detection because performance of each technique was markedly different and very dependent on local geologic conditions. Geophysical data clearly (1) image a fault zone beneath suspected warps, (2) constrain the cumulative vertical slip to only 25-30 m, (3) delineate colluvial packages suggesting coseismic surface faulting episodes. Paleoseismological investigations document at least three deformation events during the very Late Pleistocene (<20 ka) and Holocene. The clue to surface-rupturing episodes, together with the fault dimension inferred by geological mapping and microseismicity distribution, suggest a seismogenic potential of M6.3. Our study provides the second documentation of a major active fault in southern Italy that, as the Irpinia Fault, does not bound a large intermontane basin, but it is nested within the mountain range, weakly modifying the landscape. This demonstrates that standard geomorphological approaches are insufficient to define a proper framework of active faults in this region. More in general, our applications have wide

  14. High-resolution nanoprobe X-ray fluorescence characterization of heterogeneous calcium and heavy metal distributions in alkali-activated fly ash.

    PubMed

    Provis, John L; Rose, Volker; Bernal, Susan A; van Deventer, Jannie S J

    2009-10-01

    The nanoscale distribution of elements within fly ash and the aluminosilicate gel products of its alkaline activation ("fly ash geopolymers") are analyzed by means of synchrotron X-ray fluorescence using a hard X-ray Nanoprobe instrument. The distribution of calcium within a hydroxide-activated (fly ash/KOH solution) geopolymer gel is seen to be highly heterogeneous, with these data providing for the first time direct evidence of the formation of discrete high-calcium particles within the binder structure of a geopolymer synthesized from a low-calcium (<2 wt % as oxides) fly ash. The silicate-activated (fly ash/potassium silicate solution) sample, by contrast, shows a much more homogeneous geopolymer gel binder structure surrounding the unreacted fly ash particles. This has important implications for the understanding of calcium chemistry within aluminosilicate geopolymer gel phases. Additionally, chromium and iron are seen to be very closely correlated within the structures of both fly ash and the geopolymer product and remain within the regions of the geopolymer which can be identified as unreacted fly ash particles. Given that the potential for chromium release has been one of the queries surrounding the widespread utilization of construction materials derived from fly ash, the observation that this element appears to be localized within the fly ash rather than dispersed throughout the gel binder indicates that it is unlikely to be released problematically into the environment. PMID:19788232

  15. High Resolution PDF Measurements on Ag Nanoparticles

    SciTech Connect

    Rocha, Tulio C. R.; Martin, Chris; Kycia, Stefan; Zanchet, Daniela

    2009-01-29

    The quantitative analysis of structural defects in Ag nanoparticles was addressed in this work. We performed atomic scale structural characterization by a combination of x-ray diffraction (XRD) using the Pair Distribution Function analysis (PDF) and High Resolution Transmission Electron Microscopy (HRTEM). The XRD measurements were performed using an innovative instrumentation setup to provide high resolution PDF patterns.

  16. High resolution scintillation detector with semiconductor readout

    DOEpatents

    Levin, Craig S.; Hoffman, Edward J.

    2000-01-01

    A novel high resolution scintillation detector array for use in radiation imaging such as high resolution Positron Emission Tomography (PET) which comprises one or more parallelepiped crystals with at least one long surface of each crystal being in intimate contact with a semiconductor photodetector such that photons generated within each crystal by gamma radiation passing therethrough is detected by the photodetector paired therewith.

  17. High resolution multimodal clinical ophthalmic imaging system

    PubMed Central

    Mujat, Mircea; Ferguson, R. Daniel; Patel, Ankit H.; Iftimia, Nicusor; Lue, Niyom; Hammer, Daniel X.

    2010-01-01

    We developed a multimodal adaptive optics (AO) retinal imager which is the first to combine high performance AO-corrected scanning laser ophthalmoscopy (SLO) and swept source Fourier domain optical coherence tomography (SSOCT) imaging modes in a single compact clinical prototype platform. Such systems are becoming ever more essential to vision research and are expected to prove their clinical value for diagnosis of retinal diseases, including glaucoma, diabetic retinopathy (DR), age-related macular degeneration (AMD), and retinitis pigmentosa. The SSOCT channel operates at a wavelength of 1 µm for increased penetration and visualization of the choriocapillaris and choroid, sites of major disease activity for DR and wet AMD. This AO system is designed for use in clinical populations; a dual deformable mirror (DM) configuration allows simultaneous low- and high-order aberration correction over a large range of refractions and ocular media quality. The system also includes a wide field (33 deg.) line scanning ophthalmoscope (LSO) for initial screening, target identification, and global orientation, an integrated retinal tracker (RT) to stabilize the SLO, OCT, and LSO imaging fields in the presence of lateral eye motion, and a high-resolution LCD-based fixation target for presentation of visual cues. The system was tested in human subjects without retinal disease for performance optimization and validation. We were able to resolve and quantify cone photoreceptors across the macula to within ~0.5 deg (~100-150 µm) of the fovea, image and delineate ten retinal layers, and penetrate to resolve features deep into the choroid. The prototype presented here is the first of a new class of powerful flexible imaging platforms that will provide clinicians and researchers with high-resolution, high performance adaptive optics imaging to help guide therapies, develop new drugs, and improve patient outcomes. PMID:20589021

  18. High Resolution Spectroscopy to Support Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Venkataraman, Malathy Devi

    2006-01-01

    The major research activities performed during the cooperative agreement enhanced our spectroscopic knowledge of molecules of atmospheric interest such as H2O (water vapor), O3 (ozone), HCN (hydrogen cyanide), CH4 (methane), NO2 (nitrogen dioxide) and CO (carbon monoxide). The data required for the analyses were obtained from two different Fourier Transform Spectrometers (FTS); one of which is located at the National Solar Observatory (NSO) on Kitt Peak, Arizona and the other instrument is located at the Pacific Northwest National Laboratories (PNNL) at Richland, Washington. The data were analyzed using a modified multispectrum nonlinear least squares fitting algorithm developed by Dr. D. Chris Benner of the College of William and Mary. The results from these studies made significant improvements in the line positons and intensities for these molecules. The measurements of pressure broadening and pressure induced line shift coefficients and the temperature dependence of pressure broadening and pressure induced shift coefficients for hundreds of infrared transitions of HCN, CO3 CH4 and H2O were also performed during this period. Results from these studies have been used for retrievals of stratospheric gas concentration profiles from data collected by several Upper Atmospheric Research Satellite (UARS) infrared instruments as well as in the analysis of high resolution atmospheric spectra such as those acquired by space-based, ground-based, and various balloon- and aircraft-borne experiments. Our results made significant contributions in several updates of the HITRAN (HIgh resolution TRANsmission) spectral line parameters database. This database enjoys worldwide recognition in research involving diversified scientific fields. The research conducted during the period 2003-2006 has resulted in publications given in this paper. In addition to Journal publications, several oral and poster presentations were given at various Scientific conferences within the United States

  19. Ecological applications of high resolution spectrometry

    NASA Technical Reports Server (NTRS)

    Lawrence, William T.

    1989-01-01

    Future directions of NASA's space program plans include a significant effort at studying the Earth as a system of interrelated ecosystems. As part of NASA's Earth Observing System (Eos) Program a series of space platforms will be launched and operated to study the Earth with a variety of active and passive instruments. Several of the Eos instruments will be capable of imaging the planet's surface reflectance on a large number of very narrow portions of the solar spectrum. After the development of appropriate algorithms, this reflectance information will be used to determine key parameters about the structure and function of terrestrial and aquatic ecosystems and the pattern and processes of those systems across large areas of the globe. Algorithm development applicable to terrestrial systems will permit the inference of ecological processes from high resolution spectrometry data, similar to that to be forthcoming from the Eos mission. The first summer was spent working with tropical soils and relating their reflectance characteristics to particle size, iron content, and color. This summer the emphasis is on vegetation and work was begun with the Forest Ecosystems Dynamics Project in the Earth Resources Branch where both optical and radar characteristics of a mixed conifer/hardwood forest in Maine are being studied for use in a ecological modeling effort. A major series of aircraft overflights will take place throughout the summer. Laboratory and field spectrometers are used to measure the spectral reflectance of a hierarchy of vegetation from individual leaves to whole canopies for eventual modeling of their nutrient content using reflectance data. Key leaf/canopy parameters are being approximated including chlorophyll, nitrogen, phosphorus, water content, and leaf specific weight using high resolution spectrometry alone. Measurements are made of carbon exchange across the landscape for input to a spatial modeling effort to gauge production within the forest. A

  20. High-resolution facies analysis and sequence stratigraphy of fluvio-deltaic depositional systems in tectonically-active basins (Jean Baptiste Lamarck Medal)

    NASA Astrophysics Data System (ADS)

    Mutti, E.

    2012-04-01

    In ancient tectonically-active basins fed by relatively small and high-gradient rivers, both marine and lacustrine fluvio-deltaic systems display similar vertical stacking patterns which are primarily controlled by high-frequency variations of sediment flux to the basin. These variations are superimposed over higher-order cycles of tectonic uplift and relative quiescence recorded by changes in the source areas, basin configuration and overall style of sedimentation.Spectacular examples of these cyclically stacked successions crop out in the upper Cretaceous and Paleogene deposits of the south-central Pyrenean foreland basin. Similar stacking patterns are also common in other basins (e.g., the Jurassic-Cretaceous Nequen basin, Argentina and the Tertiary Piedmont Basin, northwestern Italy). Sediment flux to the sea controls the high-frequency stacking pattern of ancient fluvio-deltaic depositional systems through cyclic variations in flow efficiency which is mainly a function of the magnitude and sediment concentration of river outflows during floods. These variations result in periods of inertia- and friction-dominated jet flows followed by periods during which fluvial activity dramatically decreases. These cyclic variations, which are ultimately controlled by climate and baselevelchanges (Milankowitch cycles), are recorded by m- to dam-thick facies successions that can be interpreted as the basic "building block" (in sequence-stratigraphic parlance) of larger-scale depositional sequences. Inertia-dominated periods are characterized by large-volume highly erosive hyperpycnal flows typically containing abundant skeletal debris and mudstone clasts. These flows bypass river mouths and carry sand tonearshore and shelfal regions forming m-thick packets of tabular graded sandstone beds with HCS alternating with muddier facies. These sandstones, which extend up to several km in shelfal regions and grade distally into prodeltaic sediments, are a typical and volumetrically

  1. Modeling the dynamics of a tracer particle in an elastic active gel

    NASA Astrophysics Data System (ADS)

    Ben-Isaac, E.; Fodor, É.; Visco, P.; van Wijland, F.; Gov, Nir S.

    2015-07-01

    The internal dynamics of active gels both in artificial (in vitro) model systems and inside the cytoskeleton of living cells has been extensively studied with experiments of recent years. These dynamics are probed using tracer particles embedded in the network of biopolymers together with molecular motors, and distinct nonthermal behavior is observed. We present a theoretical model of the dynamics of a trapped active particle, which allows us to quantify the deviations from equilibrium behavior, using both analytic and numerical calculations. We map the different regimes of dynamics in this system and highlight the different manifestations of activity: breakdown of the virial theorem and equipartition, different elasticity-dependent "effective temperatures," and distinct non-Gaussian distributions. Our results shed light on puzzling observations in active gel experiments and provide physical interpretation of existing observations, as well as predictions for future studies.

  2. Modeling the dynamics of a tracer particle in an elastic active gel.

    PubMed

    Ben-Isaac, E; Fodor, É; Visco, P; van Wijland, F; Gov, Nir S

    2015-07-01

    The internal dynamics of active gels both in artificial (in vitro) model systems and inside the cytoskeleton of living cells has been extensively studied with experiments of recent years. These dynamics are probed using tracer particles embedded in the network of biopolymers together with molecular motors, and distinct nonthermal behavior is observed. We present a theoretical model of the dynamics of a trapped active particle, which allows us to quantify the deviations from equilibrium behavior, using both analytic and numerical calculations. We map the different regimes of dynamics in this system and highlight the different manifestations of activity: breakdown of the virial theorem and equipartition, different elasticity-dependent "effective temperatures," and distinct non-Gaussian distributions. Our results shed light on puzzling observations in active gel experiments and provide physical interpretation of existing observations, as well as predictions for future studies. PMID:26274211

  3. Outflow activity near Hadriaca Patera, Mars: Fluid-tectonic interaction investigated with High Resolution Stereo Camera stereo data and finite element modeling

    NASA Astrophysics Data System (ADS)

    Musiol, S.; Cailleau, B.; Platz, T.; Kneissl, T.; Dumke, A.; Neukum, G.

    2011-08-01

    We investigate the formation of the outflow channels Dao and Niger Valles near the eastern rim of the Hellas impact basin, Mars. Methods used include image and topography analysis, surface age determination, and finite element modeling. Observations show that deep depressions, source regions for Dao and Niger Valles, are located in an area of shallow subsidence to the south and east of the volcano Hadriaca Patera. Cratering model ages allow for fluvial processes triggered by volcanic loading. Based on the observations, we develop a numerical model of volcanic loading on top of a poroelastic plate leading to flexure and fracturing of the lithosphere. Modeling results show that fracturing may occur up to a depth of about 6 km within an area of shallow subsidence, i.e., the moat surrounding the volcano. Depending on initial aquifer pressurization, groundwater could have reached the surface. Model discharges and channel morphometry suggest that the Dao Vallis channel never reached bankfull flow and that the wetted channel perimeter may have formed during multiple outflow events. The following scenario is proposed: (1) emplacement of a volcanic load on top of a confined, overpressurized aquifer in the early Hesperian, (2) fracturing around the load, possibly reactivated during various stages of volcanic activity, (3) channeling of groundwater to the surface along fractures and outflow channel formation during several events in the Hesperian, and (4) collapse, mass wasting and modification of depressions in the Amazonian.

  4. High-Resolution Labeling and Functional Manipulation of Specific Neuron Types in Mouse Brain by Cre-Activated Viral Gene Expression

    PubMed Central

    Kuhlman, Sandra J.; Huang, Z. Josh

    2008-01-01

    We describe a method that combines Cre-recombinase knockin mice and viral-mediated gene transfer to genetically label and functionally manipulate specific neuron types in the mouse brain. We engineered adeno-associated viruses (AAVs) that express GFP, dsRedExpress, or channelrhodopsin (ChR2) upon Cre/loxP recombination-mediated removal of a transcription-translation STOP cassette. Fluorescent labeling was sufficient to visualize neuronal structures with synaptic resolution in vivo, and ChR2 expression allowed light activation of neuronal spiking. The structural dynamics of a specific class of neocortical neuron, the parvalbumin-containing (Pv) fast-spiking GABAergic interneuron, was monitored over the course of a week. We found that although the majority of Pv axonal boutons were stable in young adults, bouton additions and subtractions on axonal shafts were readily observed at a rate of 10.10% and 9.47%, respectively, over 7 days. Our results indicate that Pv inhibitory circuits maintain the potential for structural re-wiring in post-adolescent cortex. With the generation of an increasing number of Cre knockin mice and because viral transfection can be delivered to defined brain regions at defined developmental stages, this strategy represents a general method to systematically visualize the structure and manipulate the function of different cell types in the mouse brain. PMID:18414675

  5. History of human activity in last 800 years reconstructed from combined archive data and high-resolution analyses of varved lake sediments from Lake Czechowskie, Northern Poland

    NASA Astrophysics Data System (ADS)

    Słowiński, Michał; Tyszkowski, Sebastian; Ott, Florian; Obremska, Milena; Kaczmarek, Halina; Theuerkauf, Martin; Wulf, Sabine; Brauer, Achim

    2016-04-01

    The aim of the study was to reconstruct human and landscape development in the Tuchola Pinewoods (Northern Poland) during the last 800 years. We apply an approach that combines historic maps and documents with pollen data. Pollen data were obtained from varved lake sediments at a resolution of 5 years. The chronology of the sediment record is based on varve counting, AMS 14C dating, 137Cs activity concentration measurements and tephrochronology (Askja AD 1875). We applied the REVEALS model to translate pollen percentage data into regional plant abundances. The interpretation of the pollen record is furthermore based on pollen accumulation rate data. The pollen record and historic documents show similar trends in vegetation development. During the first phase (AD 1200-1412), the Lake Czechowskie area was still largely forested with Quercus, Carpinus and Pinus forests. Vegetation was more open during the second phase (AD 1412-1776), and reached maximum openness during the third phase (AD 1776-1905). Furthermore, intensified forest management led to a transformation from mixed to pine dominated forests during this period. Since the early 20th century, the forest cover increased again with dominance of the Scots pine in the stand. While pollen and historic data show similar trends, they differ substantially in the degree of openness during the four phases with pollen data commonly suggesting more open conditions. We discuss potential causes for this discrepancy, which include unsuitable parameters settings in REVEALS and unknown changes in forest structure. Using pollen accumulation data as a third proxy record we aim to identify the most probable causes. Finally, we discuss the observed vegetation change in relation the socio-economic development of the area. This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution Analysis - ICLEA- of the Helmholtz Association and National Science Centre, Poland (grant No. 2011/01/B/ST10

  6. High Resolution Time-Series Analysis of Paleo-Climate Proxies Archived in an Actively Forming Stalagmite from Niue Island, South Pacific

    NASA Astrophysics Data System (ADS)

    Herrera, C. M.; Aharon, P.; Lambert, W. J.

    2012-12-01

    El Niño-Southern Oscillation (ENSO) is the dominant climate variability factor in today's world. Planet Earth is currently experiencing a global warming trend that raises the question of how ENSO will behave in a warmer state. An assessment of ENSO's behavior during the Medieval Warm Period (MWP, AD 950-1250) and the Little Ice Age (LIA, AD 1350-1850) will afford a better understanding of how it may interact with future global climate change. A 61-cm long, actively forming, stalagmite from an inland cave on Niue Island (19°00' S, 169°50' W) was sampled in July of 2011. A growth rate of 366 μm/yr was established on the basis of an annual growth-band counting chronology supported by precise U/Th dates. The stalagmite was sub-sampled at 300 μm intervals using a Computer Automated Mill (CAM) and the calcite powders (50-100 μg) were analyzed for stable oxygen and carbon isotopes in a Continuous Flow Isotope-Ratio Mass Spectrometer (CF-IRMS) system. Annually resolved δ18O and δ13C time-series exhibit a range of -2.0 to -5.9 (‰ VPDB) and -1.8 to -9.5 (‰ VPDB), respectively. The inter-annual and interdecadal periodicities exhibited by the isotope time-series are interpreted as manifestations of ENSO-driven rainfall variability with time. The continuous millennial proxy record presented here offers valuable insights on ENSO variability during the MWP and LIA events, respectively.

  7. Inversion of submesoscale patterns from a high-resolution Solomon Sea model: Feasibility assessment

    NASA Astrophysics Data System (ADS)

    Gaultier, Lucile; Djath, Bughsin'; Verron, Jacques; Brankart, Jean-Michel; Brasseur, Pierre; Melet, Angelique

    2014-07-01

    A high-resolution realistic numerical model of the Solomon Sea, which exhibits a high level of variability at mesoscales and submesoscales, is used to explore new avenues for data assimilation. Image data assimilation represents a powerful methodology to integrate information from high-resolution observations such as satellite sea surface temperature or chlorophyll, or high-resolution altimetric sea surface height that will be observed in the forthcoming SWOT mission. The present study investigates the feasibility and accuracy of the inversion of the dynamical submesoscale information contained in high-resolution images of sea surface temperature (SST) or salinity (SSS) to improve the estimation of oceanic surface currents. The inversion method is tested in the context of twin experiments, with SST and SSS data provided by a model of the Solomon Sea. For that purpose, synthetic tracer images are built by binarizing the norm of the gradient of SST, SSS or spiciness. The binarized tracer images are compared to the dynamical image which is derived from the Finite-Size Lyapunov Exponents. The adjustment of the dynamical image to the tracer image provides the optimal correction to be applied on the surface velocity field. The method is evaluated by comparing the result of the inversion to the reference model solution. The feasibility of the inversion of various images (SST, SSS, both SST and SSS or spiciness) is explored on two small areas of the Solomon Sea. We show that errors in the surface velocity field can be substantially reduced through the inversion of tracer images.

  8. Travel-time-based thermal tracer tomography

    NASA Astrophysics Data System (ADS)

    Somogyvári, Márk; Bayer, Peter; Brauchler, Ralf

    2016-05-01

    Active thermal tracer testing is a technique to get information about the flow and transport properties of an aquifer. In this paper we propose an innovative methodology using active thermal tracers in a tomographic setup to reconstruct cross-well hydraulic conductivity profiles. This is facilitated by assuming that the propagation of the injected thermal tracer is mainly controlled by advection. To reduce the effects of density and viscosity changes and thermal diffusion, early-time diagnostics are used and specific travel times of the tracer breakthrough curves are extracted. These travel times are inverted with an eikonal solver using the staggered grid method to reduce constraints from the pre-defined grid geometry and to improve the resolution. Finally, non-reliable pixels are removed from the derived hydraulic conductivity tomograms. The method is applied to successfully reconstruct cross-well profiles as well as a 3-D block of a high-resolution fluvio-aeolian aquifer analog data set. Sensitivity analysis reveals a negligible role of the injection temperature, but more attention has to be drawn to other technical parameters such as the injection rate. This is investigated in more detail through model-based testing using diverse hydraulic and thermal conditions in order to delineate the feasible range of applications for the new tomographic approach.

  9. NOAA's Use of High-Resolution Imagery

    NASA Technical Reports Server (NTRS)

    Hund, Erik

    2007-01-01

    NOAA's use of high-resolution imagery consists of: a) Shoreline mapping and nautical chart revision; b) Coastal land cover mapping; c) Benthic habitat mapping; d) Disaster response; and e) Imagery collection and support for coastal programs.

  10. High-Resolution Plots of Trigonometric Functions.

    ERIC Educational Resources Information Center

    Stick, Marvin E.; Stick, Michael J.

    1985-01-01

    Provides computer programs (for Apple microcomputers) for drawing (in high resolution graphics) a three-leaved rose, concentric circles, circumscribed and inscribed astroids. Sample output and discussions of the mathematics involved in the programs are included. (JN)

  11. Holocene climate change evidence from high-resolution loess/paleosol records and the linkage to fire-climate change-human activities in the Horqin dunefield in northern China

    NASA Astrophysics Data System (ADS)

    Mu, Yan; Qin, Xiaoguang; Zhang, Lei; Xu, Bing

    2016-05-01

    The combination of high-resolution sedimentary paleoclimate proxies of total organic carbon and magnetic susceptibility of a loess/paleosol section with black carbon (BC) records provides us with information about climate change and the linkage of fire-climate change-vegetation-human activities in the Horqin dunefield over the past 11,600 cal yr BP. We found that during 11,600-8000 cal yr BP (the early Holocene), the area was dominated by a dry climate. The vegetation coverage was low, which limited the extent of fire. The Holocene optimum can be placed between 8000 and 3200 cal yr BP, and during this period, anthropogenic fire was a key component of total fire occurrence as the intensity of human activity increased. The development of agricultural activities and the growing population during this period increased the use of fire for cooking food and burning for cultivation and land fertilization purposes. During 2800-2600 cal yr BP, a warm/moister climate prevailed and was associated with a high degree of pedogenesis and vegetation cover density, evident at 2700 cal yr BP. Fires may have contributed to human survival by enabling the cooking of food in the warm and wet climate. In the period since 2000 cal yr BP, fires linked to agriculture may have led to increased biomass burning associated with agricultural activity.

  12. Workshop on high-resolution, large-acceptance spectrometers

    SciTech Connect

    Zeidman, B.

    1981-01-01

    The purpose of the Workshop on High-Resolution, Large-Acceptance Spectrometers was to provide a means for exchange of information among those actively engaged in the design and construction of these new spectrometers. Thirty-seven papers were prepared for the data base.

  13. High resolution modeling of direct ocean carbon sequestration

    SciTech Connect

    Michael Follows; John Marshall

    2004-04-22

    This work has followed two themes: (1) Developing and using the adjoint of the MIT ocean biogeochemistry model to examine the efficiency of carbon sequestration in a global configuration. We have demonstrated the power of the adjoint method for systematic ocean model sensitivity studies. We have shown that the relative efficiency of carbon sequestration in the Atlantic and Pacific basins changes with the period of interest. For decadal to centennial scales, the Pacific is more efficient. On longer timescales the Atlantic is more efficient . (2) We have developed and applied a high-resolution, North Atlantic circulation and tracer model to investigate the role of the mesoscale in controlling sequestration efficiency. We show that the mesoscale eddy field, and its explicit representation, significantly affects the estimated sequestration efficiency for local sources on the Eastern US seaboard.

  14. Toward high-resolution optoelectronic retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Palanker, Daniel; Huie, Philip; Vankov, Alexander; Asher, Alon; Baccus, Steven

    2005-04-01

    It has been already demonstrated that electrical stimulation of retina can produce visual percepts in blind patients suffering from macular degeneration and retinitis pigmentosa. Current retinal implants provide very low resolution (just a few electrodes), while several thousand pixels are required for functional restoration of sight. We present a design of the optoelectronic retinal prosthetic system that can activate a retinal stimulating array with pixel density up to 2,500 pix/mm2 (geometrically corresponding to a visual acuity of 20/80), and allows for natural eye scanning rather than scanning with a head-mounted camera. The system operates similarly to "virtual reality" imaging devices used in military and medical applications. An image from a video camera is projected by a goggle-mounted infrared LED-LCD display onto the retina, activating an array of powered photodiodes in the retinal implant. Such a system provides a broad field of vision by allowing for natural eye scanning. The goggles are transparent to visible light, thus allowing for simultaneous utilization of remaining natural vision along with prosthetic stimulation. Optical control of the implant allows for simple adjustment of image processing algorithms and for learning. A major prerequisite for high resolution stimulation is the proximity of neural cells to the stimulation sites. This can be achieved with sub-retinal implants constructed in a manner that directs migration of retinal cells to target areas. Two basic implant geometries are described: perforated membranes and protruding electrode arrays. Possibility of the tactile neural stimulation is also examined.

  15. Progress on LAMOST High Resolution Spectrograph Project

    NASA Astrophysics Data System (ADS)

    Zhang, KaI

    2015-08-01

    To explore more science case, LAMOST doesn't only has strong power on celestial spectral survey but also reserves an access to high resolution spectrograph with a few optional fibers. This commissioned spectrograph gets high resolution of R=30,000 - 60,000 at a broad visible band from 370nm to 760nm. With the consideration about site seeing variation in future, single science fiber covers wider field on sky of 4.5arcsec instead of the present 3.3arcsec. An oversize Echelle R4 grating and a pre-slit image slicer are adopted to relieve the spectrograph resolution pressure. High resolution observation will parallel to the low resolution spectral survey at a small cost of losing a few fibers (10 - 20) on telescope focal plane. These science fibers will locate at the different sky areas for more approciate choice. The presentation will give the detailed design introduction and the current project status.

  16. Biological tracer method

    DOEpatents

    Strong-Gunderson, Janet M.; Palumbo, Anthony V.

    1998-01-01

    The present invention is a biological tracer method for characterizing the movement of a material through a medium, comprising the steps of: introducing a biological tracer comprising a microorganism having ice nucleating activity into a medium; collecting at least one sample of the medium from a point removed from the introduction point; and analyzing the sample for the presence of the biological tracer. The present invention is also a method for using a biological tracer as a label for material identification by introducing a biological tracer having ice nucleating activity into a material, collecting a sample of a portion of the labelled material and analyzing the sample for the presence of the biological tracer.

  17. Biological tracer method

    DOEpatents

    Strong-Gunderson, J.M.; Palumbo, A.V.

    1998-09-15

    The present invention is a biological tracer method for characterizing the movement of a material through a medium, comprising the steps of: introducing a biological tracer comprising a microorganism having ice nucleating activity into a medium; collecting at least one sample of the medium from a point removed from the introduction point; and analyzing the sample for the presence of the biological tracer. The present invention is also a method for using a biological tracer as a label for material identification by introducing a biological tracer having ice nucleating activity into a material, collecting a sample of a portion of the labelled material and analyzing the sample for the presence of the biological tracer. 2 figs.

  18. Soil radon measurements as a potential tracer of tectonic and volcanic activity

    NASA Astrophysics Data System (ADS)

    Neri, Marco; Ferrera, Elisabetta; Giammanco, Salvatore; Currenti, Gilda; Cirrincione, Rosolino; Patanè, Giuseppe; Zanon, Vittorio

    2016-04-01

    In Earth Sciences there is a growing interest in studies concerning soil-radon activity, due to its potential as a tracer of numerous natural phenomena. Our work marks an advance in the comprehension of the interplay between tectonic activity, volcanic eruptions and gas release through faults. Soil-radon measurements, acquired on Mt. Etna volcano in 2009–2011, were analyzed. Our radon probe is sensitive to changes in both volcanic and seismic activity. Radon data were reviewed in light of the meteorological parameters. Soil samples were analyzed to characterize their uranium content. All data have been summarized in a physical model which identifies the radon sources, highlights the mechanism of radon transport and envisages how such a mechanism may change as a consequence of seismicity and volcanic events. In the NE of Etna, radon is released mainly from a depth of <1400 m, with an ascent speed of >50 m/day. Three periods of anomalous gas release were found (February 2010, January and February 2011). The trigger of the first anomaly was tectonic, while the second and third had a volcanic origin. These results mark a significant step towards a better understanding of the endogenous mechanisms that cause changes in soil-radon emission at active volcanoes.

  19. Soil radon measurements as a potential tracer of tectonic and volcanic activity.

    PubMed

    Neri, Marco; Ferrera, Elisabetta; Giammanco, Salvatore; Currenti, Gilda; Cirrincione, Rosolino; Patanè, Giuseppe; Zanon, Vittorio

    2016-01-01

    In Earth Sciences there is a growing interest in studies concerning soil-radon activity, due to its potential as a tracer of numerous natural phenomena. Our work marks an advance in the comprehension of the interplay between tectonic activity, volcanic eruptions and gas release through faults. Soil-radon measurements, acquired on Mt. Etna volcano in 2009-2011, were analyzed. Our radon probe is sensitive to changes in both volcanic and seismic activity. Radon data were reviewed in light of the meteorological parameters. Soil samples were analyzed to characterize their uranium content. All data have been summarized in a physical model which identifies the radon sources, highlights the mechanism of radon transport and envisages how such a mechanism may change as a consequence of seismicity and volcanic events. In the NE of Etna, radon is released mainly from a depth of <1400 m, with an ascent speed of >50 m/day. Three periods of anomalous gas release were found (February 2010, January and February 2011). The trigger of the first anomaly was tectonic, while the second and third had a volcanic origin. These results mark a significant step towards a better understanding of the endogenous mechanisms that cause changes in soil-radon emission at active volcanoes. PMID:27079264

  20. Soil radon measurements as a potential tracer of tectonic and volcanic activity

    PubMed Central

    Neri, Marco; Ferrera, Elisabetta; Giammanco, Salvatore; Currenti, Gilda; Cirrincione, Rosolino; Patanè, Giuseppe; Zanon, Vittorio

    2016-01-01

    In Earth Sciences there is a growing interest in studies concerning soil-radon activity, due to its potential as a tracer of numerous natural phenomena. Our work marks an advance in the comprehension of the interplay between tectonic activity, volcanic eruptions and gas release through faults. Soil-radon measurements, acquired on Mt. Etna volcano in 2009–2011, were analyzed. Our radon probe is sensitive to changes in both volcanic and seismic activity. Radon data were reviewed in light of the meteorological parameters. Soil samples were analyzed to characterize their uranium content. All data have been summarized in a physical model which identifies the radon sources, highlights the mechanism of radon transport and envisages how such a mechanism may change as a consequence of seismicity and volcanic events. In the NE of Etna, radon is released mainly from a depth of <1400 m, with an ascent speed of >50 m/day. Three periods of anomalous gas release were found (February 2010, January and February 2011). The trigger of the first anomaly was tectonic, while the second and third had a volcanic origin. These results mark a significant step towards a better understanding of the endogenous mechanisms that cause changes in soil-radon emission at active volcanoes. PMID:27079264

  1. Radio evidence for AGN activity: relativistic jets as tracers of SMBHs

    NASA Astrophysics Data System (ADS)

    Kellermann, Kenneth I.

    2016-02-01

    Although the radio emission from most quasars appears to be associated with star forming activity in the host galaxy, about ten percent of optically selected quasars have very luminous relativistic jets apparently powered by a SMBH which is located at the base of the jet. When these jets are pointed close to the line of sight their apparent luminosity is enhanced by Doppler boosting and appears highly variable. High resolution radio interferometry shows directly the outflow of relativistic plasma jets from the SMBH. Apparent transverse velocities in these so-called ``blazars'' are typically about 7c but reach as much as 50c indicating true velocities within one percent of the speed of light. The jets appear to be collimated and accelerated in regions as much as a hundred parsecs downstream from the SMBH. Measurements made with Earth to space interferometers indicate apparent brightness temperatures of ~ 1014 K or more. This is well in excess of the limits imposed by inverse Compton cooling. The modest Doppler factors deduced from the observed ejection speeds appear to be inadequate to explain the high observed brightness temperatures in terms of relativistic boosting.

  2. High Resolution Rapid Revisits Insar Monitoring of Surface Deformation

    NASA Astrophysics Data System (ADS)

    Singhroy, V.; Li, J.; Charbonneau, F.

    2014-12-01

    Monitoring surface deformation on strategic energy and transportation corridors requires high resolution spatial and temporal InSAR images for mitigation and safety purposes. High resolution air photos, lidar and other satellite images are very useful in areas where the landslides can be fatal. Recently, radar interferometry (InSAR) techniques using more rapid revisit images from several radar satellites are increasingly being used in active deformation monitoring. The Canadian RADARSAT Constellation (RCM) is a three-satellite mission that will provide rapid revisits of four days interferometric (InSAR) capabilities that will be very useful for complex deformation monitoring. For instance, the monitoring of surface deformation due to permafrost activity, complex rock slide motion and steam assisted oil extraction will benefit from this new rapid revisit capability. This paper provide examples of how the high resolution (1-3 m) rapid revisit InSAR capabilities will improve our monitoring of surface deformation and provide insights in understanding triggering mechanisms. We analysed over a hundred high resolution InSAR images over a two year period on three geologically different sites with various configurations of topography, geomorphology, and geology conditions. We show from our analysis that the more frequent InSAR acquisitions are providing more information in understanding the rates of movement and failure process of permafrost triggered retrogressive thaw flows; the complex motion of an asymmetrical wedge failure of an active rock slide and the identification of over pressure zones related to oil extraction using steam injection. Keywords: High resolution, InSAR, rapid revisits, triggering mechanisms, oil extraction.

  3. High Resolution Global View of Io

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Io, the most volcanic body in the solar system is seen in the highest resolution obtained to date by NASA's Galileo spacecraft. The smallest features that can be discerned are 2.5 kilometers in size. There are rugged mountains several kilometers high, layered materials forming plateaus, and many irregular depressions called volcanic calderas. Several of the dark, flow-like features correspond to hot spots, and may be active lava flows. There are no landforms resembling impact craters, as the volcanism covers the surface with new deposits much more rapidly than the flux of comets and asteroids can create large impact craters. The picture is centered on the side of Io that always faces away from Jupiter; north is to the top.

    Color images acquired on September 7, 1996 have been merged with higher resolution images acquired on November 6, 1996 by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft. The color is composed of data taken, at a range of 487,000 kilometers, in the near-infrared, green, and violet filters and has been enhanced to emphasize the extraordinary variations in color and brightness that characterize Io's face. The high resolution images were obtained at ranges which varied from 245,719 kilometers to 403,100 kilometers.

    Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  4. Quantification of the Bioturbation Activity of Lumbriculus Variegatus Worms Using Fluorescent Particulate Tracers

    NASA Astrophysics Data System (ADS)

    Hernandez-Gonzalez, L. M.; Roche, K. R.; Xie, M.; Packman, A. I.

    2014-12-01

    Important biological, physical and chemical processes, such as fluxes of oxygen, nutrients and contaminants, occur across sediment-water interfaces. These processes are influenced by bioturbation activities of benthic animals. Bioturbation is thought to be significant in releasing metals to the water column from contaminated sediments, but metals contamination also affects organism activity. Consequently, the aim of this study was to consider the interactions of biological activity, sediment chemistry, pore water transport, and chemical reactions in sediment mixing and the flux and toxicity of metals in sediments. Prior studies have modeled bioturbation as a diffusive process. However, diffusion models often do not describe accurately sediment mixing due to bioturbation. To this end, we used the continuous time random walk (CTRW) model to assess sediment mixing caused by bioturbation activity of Lumbriculus variegatus worms. We performed experiments using fine-grained sediments with different levels of zinc contamination from Lake DePue, which is a Superfund Site in Illinois. The tests were conducted in an aerated fresh water chamber. Fluorescent particulate tracers were added to the sediment surface to quantify mixing processes and the influence of metals contaminants on L. variegatus bioturbation activity. We observed sediment mixing and organism activity by time-lapse photography over 14 days. Then, we analyzed the images to characterize the fluorescent particle concentration as a function of sediment depth and time. Results reveal that sediment mixing caused by L. variegatus is subdiffusive in time and superdiffusive in space. These results suggest that anomalous sediment mixing is probably a ubiquitous process, as this behavior has only been observed previously in marine sediments. Also, the experiments indicate that bioturbation and sediment mixing decreased in the presence of higher metals concentrations in sediments. This process is expected to decrease

  5. ELECTRONICS UPGRADE OF HIGH RESOLUTION MASS SPECTROMETERS

    SciTech Connect

    Mcintosh, J; Joe Cordaro, J

    2008-03-10

    High resolution mass spectrometers are specialized systems that allow researchers to determine the exact mass of samples to four significant digits by using magnetic and electronic sector mass analyzers. Many of the systems in use today at research laboratories and universities were designed and built more than two decades ago. The manufacturers of these systems have abandoned the support for some of the mass spectrometers and parts to power and control them have become scarce or obsolete. The Savannah River National Laboratory has been involved in the upgrade of the electronics and software for these legacy machines. The Electronics Upgrade of High Resolution Mass Spectrometers consists of assembling high-end commercial instrumentation from reputable manufacturers with a minimal amount of customization to replace the electronics for the older systems. By taking advantage of advances in instrumentation, precise magnet control can be achieved using high resolution current sources and continuous feedback from a high resolution hall-effect probe. The custom equipment include a precision voltage divider/summing amplifier chassis, high voltage power supply chassis and a chassis for controlling the voltage emission for the mass spectrometer source tube. The upgrade package is versatile enough to interface with valve control, vacuum and other instrumentation. Instrument communication is via a combination of Ethernet and traditional IEEE-488 GPIB protocols. The system software upgrades include precision control, feedback and spectral waveform analysis tools.

  6. A High-Resolution Stopwatch for Cents

    ERIC Educational Resources Information Center

    Gingl, Z.; Kopasz, K.

    2011-01-01

    A very low-cost, easy-to-make stopwatch is presented to support various experiments in mechanics. The high-resolution stopwatch is based on two photodetectors connected directly to the microphone input of a sound card. Dedicated free open-source software has been developed and made available to download. The efficiency is demonstrated by a free…

  7. Evacuee Compliance Behavior Analysis using High Resolution Demographic Information

    SciTech Connect

    Lu, Wei; Han, Lee; Liu, Cheng; Tuttle, Mark A; Bhaduri, Budhendra L

    2014-01-01

    The purpose of this study is to examine whether evacuee compliance behavior with route assignments from different resolutions of demographic data would impact the evacuation performance. Most existing evacuation strategies assume that travelers will follow evacuation instructions, while in reality a certain percent of evacuees do not comply with prescribed instructions. In this paper, a comparison study of evacuation assignment based on Traffic Analysis Zones (TAZ) and high resolution LandScan USA Population Cells (LPC) were conducted for the detailed road network representing Alexandria, Virginia. A revised platform for evacuation modeling built on high resolution demographic data and activity-based microscopic traffic simulation is proposed. The results indicate that evacuee compliance behavior affects evacuation efficiency with traditional TAZ assignment, but it does not significantly compromise the efficiency with high resolution LPC assignment. The TAZ assignment also underestimates the real travel time during evacuation, especially for high compliance simulations. This suggests that conventional evacuation studies based on TAZ assignment might not be effective at providing efficient guidance to evacuees. From the high resolution data perspective, traveler compliance behavior is an important factor but it does not impact the system performance significantly. The highlight of evacuee compliance behavior analysis should be emphasized on individual evacuee level route/shelter assignments, rather than the whole system performance.

  8. Tracers for monitoring the activity of sodium/glucose cotransporters in health and disease

    DOEpatents

    Wright, Ernest M; Barrio, Jorge R; Hirayama, Bruce A; Kepe, Vladimir

    2014-09-30

    Radiolabeled tracers for sodium/glucose cotransporters (SGLTs), their synthesis, and their use are provided. The tracers are methyl or ethyl pyranosides having an equatorial hydroxyl group at carbon-2 and a C 1 preferred conformation, radiolabeled with .sup.18F, .sup.123I, or .sup.124I, or free hexoses radiolabeled with .sup.18F, .sup.123I, or .sup.124. Also provided are in vivo and in vitro techniques for using these and other tracers as analytical and diagnostic tools to study glucose transport, in health and disease, and to evaluate therapeutic interventions.

  9. High-resolution display system for mammograms

    NASA Astrophysics Data System (ADS)

    Moskowitz, Michael J.; Huang, H. K.; Wang, Jun; Allen, Jeffrey; Sickles, Edward A.; Giles, Anthony

    1995-04-01

    A high resolution mammographic display station is implemented for clinical diagnosis and for a digital teaching file. The display consists of a specially designed, high resolution mammographic station which contains a connection to a 50 micron (variable spot size) laser film digitizer, two 2 K X 2.5 K display monitors, an image processor, a host computer, and a disk array for high speed image transfer to the display monitors. After digitization on a separate host computer, the files are immediately transferred to the display station and post- processed for viewing. The algorithm for post-processing of the digitized image applies a non- linear LUT to mimic the original film characteristics while taking into account the luminosity of the display monitors in an attempt to produce the highest digital image quality possible. Image processing functions for enhancing calcification and soft tissue are also available to assist the human observer in classification of objects within the image. Windowing and level controls are seamlessly integrated for each monitor, as well as magnification capabilities. For an image display at its full resolution (e.g., digitized at 100 microns), the magnification is accomplished with a roaming window utilizing simple 2X pixel replication. This has been found to be acceptable in preliminary tests with clinicians. Measurements of features on the 2 k displays are possible, as well. The display format accurately simulates mammographic viewing arrangements with automatic side-by-side historical, current, left and right craniocaudal, mediolateral, etc., view comparisons. This high resolution mammographic display is found to be essential for fast and accurate display of high resolution digitized mammograms. A digital mammographic teaching file has been designed and tested using this display architecture. The teaching file presents the case questions on the host display monitor, and the related images for each question are presented on the high

  10. Direct analysis of prostaglandin-E2 and -D2 produced in an inflammatory cell reaction and its application for activity screening and potency evaluation using turbulent flow chromatography liquid chromatography-high resolution mass spectrometry.

    PubMed

    Shin, Jeong-Sook; Peng, Lei; Kang, Kyungsu; Choi, Yongsoo

    2016-09-01

    Direct analysis of prostaglandin-E2 (PGE2) and -D2 (PGD2) produced from a RAW264.7 cell-based reaction was performed by liquid chromatography high-resolution mass spectrometry (LC-HRMS), which was online coupled with turbulent flow chromatography (TFC). The capability of this method to accurately measure PG levels in cell reaction medium containing cytokines or proteins as a reaction byproduct was cross-validated by two conventional methods. Two methods, including an LC-HRMS method after liquid-liquid extraction (LLE) of the sample and a commercial PGE2 enzyme-linked immunosorbent assay (ELISA), showed PGE2 and/or PGD2 levels almost similar to those obtained by TFC LC-HRMS over the reaction time after LPS stimulation. After the cross-validation, significant analytical throughputs, allowing simultaneous screening and potency evaluation of 80 natural products including 60 phytochemicals and 20 natural product extracts for the inhibition of the PGD2 produced in the cell-based inflammatory reaction, were achieved using the TFC LC-HRMS method developed. Among the 60 phytochemicals screened, licochalcone A and formononetin inhibited PGD2 production the most with IC50 values of 126 and 151nM, respectively. For a reference activity, indomethacin and diclofenac were used, measuring IC50 values of 0.64 and 0.21nM, respectively. This method also found a butanol extract of Akebia quinata Decne (AQ) stem as a promising natural product for PGD2 inhibition. Direct and accurate analysis of PGs in the inflammatory cell reaction using the TFC LC-HRMS method developed enables the high-throughput screening and potency evaluation of as many as 320 samples in less than 48h without changing a TFC column. PMID:27524299

  11. Determination of palladium, platinum and rhodium in used automobile catalysts and active pharmaceutical ingredients using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis

    NASA Astrophysics Data System (ADS)

    Resano, Martín; Flórez, María del Rosario; Queralt, Ignasi; Marguí, Eva

    2015-03-01

    This work investigates the potential of high-resolution continuum source graphite furnace atomic absorption spectrometry for the direct determination of Pd, Pt and Rh in two samples of very different nature. While analysis of active pharmaceutical ingredients is straightforward and it is feasible to minimize matrix effects, to the point that calibration can be carried out against aqueous standard solutions, the analysis of used automobile catalysts is more challenging requiring the addition of a chemical modifier (NH4F·HF) to help in releasing the analytes, a more vigorous temperature program and the use of a solid standard (CRM ERM®-EB504) for calibration. However, in both cases it was possible to obtain accurate results and precision values typically better than 10% RSD in a fast and simple way, while only two determinations are needed for the three analytes, since Pt and Rh can be simultaneously monitored in both types of samples. Overall, the methods proposed seem suited for the determination of these analytes in such types of samples, offering a greener and faster alternative that circumvents the traditional problems associated with sample digestion, requiring a small amount of sample only (0.05 mg per replicate for catalysts, and a few milligrams for the pharmaceuticals) and providing sufficient sensitivity to easily comply with regulations. The LODs achieved were 6.5 μg g- 1 (Pd), 8.3 μg g- 1 (Pt) and 9.3 μg g- 1 (Rh) for catalysts, which decreased to 0.08 μg g- 1 (Pd), 0.15 μg g- 1 (Pt) and 0.10 μg g- 1 (Rh) for pharmaceuticals.

  12. Shallow subsurface imaging of the Piano di Pezza active normal fault (central Italy) by high-resolution refraction and electrical resistivity tomography coupled with time-domain electromagnetic data

    NASA Astrophysics Data System (ADS)

    Villani, Fabio; Tulliani, Valerio; Sapia, Vincenzo; Fierro, Elisa; Civico, Riccardo; Pantosti, Daniela

    2015-12-01

    The Piano di Pezza fault is the central section of the 35 km long L'Aquila-Celano active normal fault-system in the central Apennines of Italy. Although palaeoseismic data document high Holocene vertical slip rates (˜1 mm yr-1) and a remarkable seismogenic potential of this fault, its subsurface setting and Pleistocene cumulative displacement are still poorly known. We investigated for the first time the shallow subsurface of a key section of the main Piano di Pezza fault splay by means of high-resolution seismic and electrical resistivity tomography coupled with time-domain electromagnetic soundings (TDEM). Our surveys cross a ˜5-m-high fault scarp that was generated by repeated surface-rupturing earthquakes displacing Holocene alluvial fans. We provide 2-D Vp and resistivity images, which show significant details of the fault structure and the geometry of the shallow basin infill material down to 50 m depth. Our data indicate that the upper fault termination has a sub-vertical attitude, in agreement with palaeoseismological trench evidence, whereas it dips ˜50° to the southwest in the deeper part. We recognize some low-velocity/low-resistivity regions in the fault hangingwall that we relate to packages of colluvial wedges derived from scarp degradation, which may represent the record of some Holocene palaeo-earthquakes. We estimate a ˜13-15 m throw of this fault splay since the end of the Last Glacial Maximum (˜18 ka), leading to a 0.7-0.8 mm yr-1 throw rate that is quite in accordance with previous palaeoseismic estimation of Holocene vertical slip rates. The 1-D resistivity models from TDEM soundings collected along the trace of the electrical profile significantly match with 2-D resistivity images. Moreover, they indicate that in the fault hangingwall, ˜200 m away from the surface fault trace, the pre-Quaternary carbonate basement is at ˜90-100 m depth. We therefore provide a minimal ˜150-160 m estimate of the cumulative throw of the Piano di Pezza

  13. High resolution 3D nonlinear integrated inversion

    NASA Astrophysics Data System (ADS)

    Li, Yong; Wang, Xuben; Li, Zhirong; Li, Qiong; Li, Zhengwen

    2009-06-01

    The high resolution 3D nonlinear integrated inversion method is based on nonlinear theory. Under layer control, the log data from several wells (or all wells) in the study area and seismic trace data adjacent to the wells are input to a network with multiple inputs and outputs and are integratedly trained to obtain an adaptive weight function of the entire study area. Integrated nonlinear mapping relationships are built and updated by the lateral and vertical geologic variations of the reservoirs. Therefore, the inversion process and its inversion results can be constrained and controlled and a stable seismic inversion section with high resolution with velocity inversion, impedance inversion, and density inversion sections, can be gained. Good geologic effects have been obtained in model computation tests and real data processing, which verified that this method has high precision, good practicality, and can be used for quantitative reservoir analysis.

  14. Initial tests of a high resolution Scintillating Fibre (SCIFI) tracker

    NASA Astrophysics Data System (ADS)

    Atkinson, M.; Fent, J.; Fisher, C.; Freund, P.; Hughes, P.; Kirkby, J.; Osthoff, A.; Pretzl, K.

    1987-03-01

    We present our initial measurements of high resolution particle tracking in scintillating fibre (SCIFI) detectors. The scintillator under study is a glass, designated GS1, which is doped with the cerium (Ce 3+) emitter. We conclude from our measurements that present SCIFI detectors can be successfully used as small-volume "active" targets, but that further developments are necessary before this technique can be applied to high precision tracking in collider detectors.

  15. Petrous apex mucocele: high resolution CT.

    PubMed

    Memis, A; Memis, A; Alper, H; Calli, C; Ozer, H; Ozdamar, N

    1994-11-01

    Mucocele of the petrous apex is very rare, only three cases having been reported. Since this area is inaccessible to direct examination, imaging, preferably high resolution computed tomography (HR CT) is essential. We report a case showing an eroding, non enhancing mass with sharp, lobulated contours, within the petrous apex. The presence of a large air cell on the opposite side suggested a mucocele. PMID:7862284

  16. High resolution schemes for hyperbolic conservation laws

    NASA Technical Reports Server (NTRS)

    Harten, A.

    1983-01-01

    A class of new explicit second order accurate finite difference schemes for the computation of weak solutions of hyperbolic conservation laws is presented. These highly nonlinear schemes are obtained by applying a nonoscillatory first order accurate scheme to an appropriately modified flux function. The so-derived second order accurate schemes achieve high resolution while preserving the robustness of the original nonoscillatory first order accurate scheme. Numerical experiments are presented to demonstrate the performance of these new schemes.

  17. Star formation seen with high resolution spectroscopy.

    NASA Astrophysics Data System (ADS)

    Winnewisser, G.

    1990-03-01

    More than 90 anorganic and organic molecules have been detected by high resolution spectroscopy in interstellar molecular clouds or in the envelopes of stars. The detected wavelengths of the lines - predominantly located in the millimeter- and submillimeter wavelength region - unequivocally identify the molecules and give precise knowledge of the physical and chemical conditions of molecular clouds from which the radiation emanates. The line intensities and line profiles contain information about the densities, temperatures and dynamics prevailing in molecular clouds.

  18. High resolution imaging of boron carbide microstructures

    SciTech Connect

    Mackinnon, I.D.R.; Aselage, T.; Van Deusen, S.B.

    1985-08-01

    Two samples of boron carbide have been examined using high resolution transmission electron microscopy (HRTEM). A hot-pressed B/sub 13/C/sub 2/ sample shows a high density of variable width twins normal to (10*1). Subtle shifts or offsets of lattice fringes along the twin plane and normal to approx.(10*5) were also observed. A B/sub 4/C powder showed little evidence of stacking disorder in crystalline regions.

  19. High resolution imaging of boron carbide microstructures

    SciTech Connect

    MacKinnon, I.D.R.; Aselage, T.; Van Deusen, S.B.

    1986-04-15

    Two samples of boron carbide have been examined using high resolution transmission electron microscopy (HRTEM). A hot-pressed B/sub 13/C/sub 2/ sample shows a high density of variable width twins normal to (10*1). Subtle shifts or offsets of lattice fringes along the twin plane and normal to approx.(10*5) were also observed. A B/sub 4/C powder showed little evidence of stacking disorder in crystalline regions.

  20. High-Resolution X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    ODell, Stephen L.; Brissenden, Roger J.; Davis, William; Elsner, Ronald F.; Elvis, Martin; Freeman, Mark; Gaetz, Terry; Gorenstein, Paul; Gubarev, Mikhail V.

    2010-01-01

    Fundamental needs for future x-ray telescopes: a) Sharp images => excellent angular resolution. b) High throughput => large aperture areas. Generation-X optics technical challenges: a) High resolution => precision mirrors & alignment. b) Large apertures => lots of lightweight mirrors. Innovation needed for technical readiness: a) 4 top-level error terms contribute to image size. b) There are approaches to controlling those errors. Innovation needed for manufacturing readiness. Programmatic issues are comparably challenging.

  1. Conversational high resolution mass spectrographic data reduction

    NASA Technical Reports Server (NTRS)

    Romiez, M. P.

    1973-01-01

    A FORTRAN 4 program is described which reduces the data obtained from a high resolution mass spectrograph. The program (1) calculates an accurate mass for each line on the photoplate, and (2) assigns elemental compositions to each accurate mass. The program is intended for use in a time-shared computing environment and makes use of the conversational aspects of time-sharing operating systems.

  2. High-Resolution Traction Force Microscopy

    PubMed Central

    Plotnikov, Sergey V.; Sabass, Benedikt; Schwarz, Ulrich S.; Waterman, Clare M.

    2015-01-01

    Cellular forces generated by the actomyosin cytoskeleton and transmitted to the extracellular matrix (ECM) through discrete, integrin-based protein assemblies, that is, focal adhesions, are critical to developmental morphogenesis and tissue homeostasis, as well as disease progression in cancer. However, quantitative mapping of these forces has been difficult since there has been no experimental technique to visualize nanonewton forces at submicrometer spatial resolution. Here, we provide detailed protocols for measuring cellular forces exerted on two-dimensional elastic substrates with a high-resolution traction force microscopy (TFM) method. We describe fabrication of polyacrylamide substrates labeled with multiple colors of fiducial markers, functionalization of the substrates with ECM proteins, setting up the experiment, and imaging procedures. In addition, we provide the theoretical background of traction reconstruction and experimental considerations important to design a high-resolution TFM experiment. We describe the implementation of a new algorithm for processing of images of fiducial markers that are taken below the surface of the substrate, which significantly improves data quality. We demonstrate the application of the algorithm and explain how to choose a regularization parameter for suppression of the measurement error. A brief discussion of different ways to visualize and analyze the results serves to illustrate possible uses of high-resolution TFM in biomedical research. PMID:24974038

  3. Application of Advanced Very High Resolution Radiometer vegetation index to study atmosphere-biosphere exchange of CO2

    NASA Technical Reports Server (NTRS)

    Fung, I. Y.; Tucker, C. J.; Prentice, K. C.

    1987-01-01

    Normalized difference vegetation indices derived from radiances measured by the Advanced Very High Resolution Radiometer were used to prescribe the phasing of terrestrial photosynthesis. The satellite data were combined with field data on soil respiration and a global map of net primary productivity to obtain the seasonal exchange of CO2 between the atmosphere and the terrestrial biosphere. The monthly fluxes of CO2 thus obtained were employed as source/sink functions in a global three-dimensional atmospheric tracer transport model to simulate the annual oscillations of CO2 in the atmosphere. The results demonstrate that satellite data of high spatial and temporal resolution can be used to provide quantitative information about seasonal and longer-term variations of photosynthetic activity on a global scale.

  4. High-Resolution Vertical Observation of Intracellular Structure Using Magnetically Responsive Microplates.

    PubMed

    Teshima, Tetsuhiko; Onoe, Hiroaki; Tottori, Soichiro; Aonuma, Hiroka; Mizutani, Takeomi; Kamiya, Koki; Ishihara, Hirotaka; Kanuka, Hirotaka; Takeuchi, Shoji

    2016-07-01

    A vertical confocal observation system capable of high-resolution observation of intracellular structure is demonstrated. The system consists of magnet-active microplates to rotate, incline, and translate single adherent cells in the applied magnetic field. Appended to conventional confocal microscopes, this system enables high-resolution cross-sectional imaging with single-molecule sensitivity in single scanning. PMID:27185344

  5. High-resolution dot-matrix hologram generation

    NASA Astrophysics Data System (ADS)

    Zarkov, Boban; Grujić, Dušan; Pantelić, Dejan

    2012-05-01

    Holography is a technique that enables us to permanently record three-dimensional (3D) colour pictures. Owing to their sub-micron structure, holograms are remarkable safety devices that are very difficult to counterfeit. Dot-matrix technology, which is one of the commonly used methods, is a substantial obstacle to all types of fraudulent activities. This kind of hologram is mainly used for the purpose of protection against forgery of cheques, cards, passports, etc. Such a high-resolution technique also enables the engineering of 2D and 3D structures, potentially leading to the construction of metamaterials. In this paper, we describe high-resolution holographic structures obtained by dot-matrix devices of novel construction.

  6. Sparse Recovery Analysis of High-Resolution Climate Data

    NASA Astrophysics Data System (ADS)

    Archibald, R.

    2013-12-01

    The field of compressed sensing is vast and currently very active, with new results, methods, and algorithms appearing almost daily. The first notions of compressed sensing began with Prony's method, which was designed by the French mathematician Gaspard Riche de Prony to extract signal information from a limited number of measurements. Since then, sparsity has been used empirically in a variety of applications, including geology and geophysics, spectroscopy, signal processing, radio astronomy, and medical ultrasound. High-resolution climate studies performed on large scale high performance computing have been producing large amounts of data that can benefit from unique mathematical methods for analysis. This work demonstrates how sparse recovery and L1 regularization can be used effectively on large datasets from high-resolution climate studies.

  7. Performance Optimization of NEMO Oceanic Model at High Resolution

    NASA Astrophysics Data System (ADS)

    Epicoco, Italo; Mocavero, Silvia; Aloisio, Giovanni

    2014-05-01

    The NEMO oceanic model is based on the Navier-Stokes equations along with a nonlinear equation of state, which couples the two active tracers (temperature and salinity) to the fluid velocity. The code is written in Fortan 90 and parallelized using MPI. The resolution of the global ocean models used today for climate change studies limits the prediction accuracy. To overcome this limit, a new high-resolution global model, based on NEMO, simulating at 1/16° and 100 vertical levels has been developed at CMCC. The model is computational and memory intensive, so it requires many resources to be run. An optimization activity is needed. The strategy requires a preliminary analysis to highlight scalability bottlenecks. It has been performed on a SandyBridge architecture at CMCC. An efficiency of 48% on 7K cores (the maximum available) has been achieved. The analysis has been also carried out at routine level, so that the improvement actions could be designed for the entire code or for the single kernel. The analysis highlighted for example a loss of performance due to the routine used to implement the north fold algorithm (i.e. handling the points at the north pole of the 3-poles Grids): indeed an optimization of the routine implementation is needed. The folding is achieved considering only the last 4 rows on the top of the global domain and by applying a rotation pivoting on the point in the middle. During the folding, the point on the top left is updated with the value of the point on bottom right and so on. The current version of the parallel algorithm is based on the domain decomposition. Each MPI process takes care of a block of points. Each process can update its points using values belonging to the symmetric process. In the current implementation, each received message is placed in a buffer with a number of elements equal to the total dimension of the global domain. Each process sweeps the entire buffer, but only a part of that computation is really useful for the

  8. High-Resolution Spectroscopy of Some Very Inactive Southern Stars

    NASA Astrophysics Data System (ADS)

    Villarreal, A.; King, J. R.; Soderblom, D. R.; Henry, T. J.

    2001-12-01

    We have obtained high-resolution echelle spectra of a few dozen solar-type stars that an earlier low resolution Ca II H & K survey suggested have modest evels of chromospheric activity. We present Hα -based chromospheric activity measures, binarity information, and Li abundances of the sample. As expected, our spectra: confirm the low levels of chromospheric activity; suggest that these objects are apparently single; indicate the stars have small projected rotational velocities; and yield low photospheric abundances of Li. This work was supported by NSF grant AST-0086576 to JRK.

  9. Predicting/Extrapolating Active Layer Thickness Using Statistical Learning from Remotely-Sensed High-resolution Data in Arctic Permafrost Landscapes: Improved parameterization of Ice-wedge polygons from LiDAR/WorldView-2 derived metrics

    NASA Astrophysics Data System (ADS)

    Gangodagamage, C.; Rowland, J. C.; Hubbard, S. S.; Brumby, S. P.; Liljedahl, A.; Wainwright, H. M.; Sloan, V. L.; Altmann, G.; Skurikhin, A. N.; Shelef, E.; Wilson, C. J.; Dafflon, B.; Peterson, J.; Ulrich, C.; Gibbs, A.; Tweedie, C. E.; Painter, S. L.; Wullschleger, S. D.

    2014-12-01

    Landscape attributes that vary with micro-topography, such as active layer thickness (ALT) in ice-wedge polygon ground, are labor-intensive to document in the field at large spatial extents, necessitating remotely sensed methods. Robust techniques to estimate ALT over large areas would improve understanding of coupled dynamics between permafrost, hydrology and landsurface processes, and improve simulations of the rate and timing of release of soil carbon from permafrost settings. In particular, it would provide critically needed data to parameterize and initialize soil property information in permafrost models and evaluate model predictions for large, complex domains. In this work, we demonstrate a new data fusion approach using high-resolution remotely sensed data for estimating cm scale ALT in a 5 km2 area of ice-wedge polygon terrain in Barrow, Alaska. We used topographic (directed distance, slope, wavelet-curvature) and spectral (NDVI) metrics derived from multisensor data obtained from LiDAR and WorldView-2 platforms to develop a simple data fusion algorithm using statistical machine learning. This algorithm was used to estimate ALT (2 m spatial resolution) across the study area. A comparison of the estimates with ground-based measurements documented the accuracy (±4.4 cm, r2=0.76) of the approach. Our findings suggest that the broad climatic variability associated with warming air temperature will govern the regional averages of ALT, but the smaller-scale variability could be controlled by local eco-hydro-geomorphic variables. This work demonstrates a path forward for mapping subsurface properties over large areas from readily available remote sensing data. Methodology of Mapping and Characterization Polygons:We convolve LiDAR elevations with multiscale wavelets and objectively chose appropriate scales to map interconnected troughs of high- and low-centered polygons. For the ice wedges where LiDAR surface expressions (troughs) are not well developed, we used

  10. High resolution SAR applications and instrument design

    NASA Technical Reports Server (NTRS)

    Dionisio, C.; Torre, A.

    1993-01-01

    The Synthetic Aperture Radar (SAR) has viewed, in the last two years, a huge increment of interest from many preset and potential users. The good spatial resolution associated to the all weather capability lead to considering SAR not only a scientific instrument but a tool for verifying and controlling the daily human relationships with the Earth Environment. New missions were identified for SAR as spatial resolution became lower than three meters: disasters, pollution, ships traffic, volcanic eruptions, earthquake effect are only a few of the possible objects which can be effectively detected, controlled and monitored by SAR mounted on satellites. High resolution radar design constraints and dimensioning are discussed.

  11. High resolution extremity CT for biomechanics modeling

    SciTech Connect

    Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

    1995-09-23

    With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling.

  12. High Resolution Sapphire Bragg Backscattering Monochromator

    SciTech Connect

    Linden, P. van der; Wille, H.-C.; Shvyd'ko, Yu. V.

    2007-01-19

    We present a temperature stabilised high resolution sapphire backscattering monochromator. The device consists of a sapphire crystal inside a cold nitrogen gas cooled, temperature stabilised chamber with a passively temperature stabilised screen. The achieved temperature stability of {+-}2mK allows for an energy resolution of {delta}E/E {<=} 10-7 at energies in the range of 30-70 keV. The device was developed for nuclear resonant scattering above 30 keV, where appropriate solutions did not exist until now.

  13. A High Resolution Scale-of-four

    DOE R&D Accomplishments Database

    Fitch, V.

    1949-08-25

    A high resolution scale-of-four has been developed to be used in conjunction with the nuclear particle detection devices in applications where the counting rate is unusually high. Specifically, it is intended to precede the commercially available medium resolution scaling circuits and so decrease the resolving time of the counting system. The circuit will function reliably on continuously recurring pulses separated by less than 0.1 microseconds. It will resolve two pulses (occurring at a moderate repetition rate) which are spaced at 0.04 microseconds. A five-volt input signal is sufficient to actuate the device.

  14. High-Resolution Manometry in Clinical Practice

    PubMed Central

    Pandolfino, John E.

    2015-01-01

    High-resolution manometry (HRM) is the primary method used to evaluate esophageal motor function. Displayed and interpreted by esophageal pressure topography (EPT), HRM/ EPT provides a detailed assessment of esophageal function that is useful in the evaluation of patients with nonobstructive dysphagia and before foregut surgery. Esophageal motility diagnoses are determined systematically by applying objective metrics of esophageal sphincter and peristaltic function to the Chicago Classification of esophageal motility disorders. This article discusses HRM study, EPT interpretation, and the translation of EPT findings into clinical practice. Examples are provided to illustrate several clinical challenges. PMID:27118931

  15. High resolution interferometry of cool stars

    NASA Technical Reports Server (NTRS)

    Lambert, D. L.

    1974-01-01

    A description is given of results obtained in a program of infrared high resolution spectroscopy of cool stars. The nature of infrared stellar spectra is considered along with questions regarding astrophysics and stellar infrared spectroscopy. An abundance analysis for alpha Ori (Betelgeuse) is conducted. The C-12/C-13 abundance ratio is examined and attention is given to the O-16/O-18 and O-16/O-17 abundance ratios. M stars and SiO vibration-rotation bands are discussed and questions regarding the characteristics of the molecular hydrogen quadrupole vibration-rotation lines are explored.

  16. A Portable, High Resolution, Surface Measurement Device

    NASA Technical Reports Server (NTRS)

    Ihlefeld, Curtis M.; Burns, Bradley M.; Youngquist, Robert C.

    2012-01-01

    A high resolution, portable, surface measurement device has been demonstrated to provide micron-resolution topographical plots. This device was specifically developed to allow in-situ measurements of defects on the Space Shuttle Orbiter windows, but is versatile enough to be used on a wide variety of surfaces. This paper discusses the choice of an optical sensor and then the decisions required to convert a lab bench optical measurement device into an ergonomic portable system. The necessary trade-offs between performance and portability are presented along with a description of the device developed to measure Orbiter window defects.

  17. High-resolution color photographic reproductions

    NASA Astrophysics Data System (ADS)

    McCann, John J.

    1997-04-01

    This paper will describe a fine-art reproduction process that: captures painting information with high-resolution color photographs; scans the information into a 300 megabyte digital file; performs a 3D color calibration in a dedicated hardware color-transform circuit; makes a master positive color transparency and makes a reproduction on polaroid color print film. The master transparency can be used to expose a large number of images. This combines the efficiency of instant photography with the color fidelity of digital color transforms.

  18. High-resolution scanning hall probe microscopy

    NASA Astrophysics Data System (ADS)

    Hicks, Clifford; Luan, Lan; Hendrik Bluhm, J.; Moler, Kathryn; Guikema, Janice; Zeldov, Eli; Shtrikman, Hadas

    2006-03-01

    Scanning hall sensors can be used to directly image magnetic fields at surfaces. They offer high resolution, high sensitivity, operability over a broad temperature range, and linearity. We have fabricated hall sensors on GaAs / Al0.35Ga0.65As and GaAs / Al0.3Ga0.7As heterostructures containing 2D electron gases 40, 39 and 140nm beneath the surface. The sensitive areas of our probes range from microns to 85nm on a side. We report on the field sensitivities of probes of various sizes and their spatial resolution in a scanning configuration.

  19. ALMA Debuts High-Resolution Results

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-07-01

    through space as it orbits the Sun. The resolution of these images — enough to study the shape and even some surface features of the asteroid! — are unprecedented for this wavelength. HL Tau is a young star surrounded by a protoplanetary disk. ALMA's detailed observations of this region revealed remarkable structure within the disk: a series of light and dark concentric rings indicative of planets caught in the act of forming. Studying this system will help us understand how multi-planet solar systems like our own form and evolve. The star-forming galaxy SDP.81 — located so far away that the light we see was emitted when the Universe was only 15% of its current age — is gravitationally-lensed into a cosmic arc, due to the convenient placement of a nearby foreground galaxy. The combination of the lucky alignment and ALMA's high resolution grant us a spectacularly detailed view of this distant galaxy, allowing us to study its actual shape and the motion within it. The observations from ALMA's first test of its long baseline demonstrate that ALMA is capable of doing the transformational science it promised. As we gear up for the next cycle of observations, it's clear that exciting times are ahead! Citation: ALMA ship et al. 2015 ApJ 808 L1, L2, L3 and L4. Focus on the ALMA Long Baseline Campaign

  20. High resolution seismic tomography of a Strombolian volcanic cone

    NASA Astrophysics Data System (ADS)

    Brenguier, F.; Coutant, O.; Baudon, H.; Doré, F.; Dietrich, M.

    2006-08-01

    We determine the 3D velocity structure of the Puy des Goules, a small, 1 km wide, Strombolian volcano that erupted 10 ky ago in central France, through a high resolution seismic survey. One major goal for this experiment was to develop methods to reach a high resolution focused on the plumbing system. This has raised different problems such as: mixing active sources (explosive, vibroseis) with different signal properties; inverting traveltime residuals of the order of 10 ms which requires the corresponding accuracy on the Digital Elevation Model (DEM), source and sensor locations (300 sites) and traveltime computations. The results of the traveltime tomography reveal three main bodies of high velocity embedded within scoria layers. These bodies can be interpreted as the central chimney and two complex feeding zones that compare quite well with the Puy de Lemptégy, a neighboring cone that was quarried and removed, showing its underlying feeding conduits and dykes. These results represent a first step toward our objective that is to determine geological structures related to natural hazards with a high resolution.

  1. New Challenges in High-Resolution Modeling of Hurricanes

    NASA Astrophysics Data System (ADS)

    Chen, S. S.

    2006-12-01

    The extreme active Atlantic hurricane seasons in recent years have highlighted the urgent need for a better understanding of the factors that contribute to hurricane intensity and for development of the corresponding advanced hurricane prediction models to improve intensity forecasts. The lack of skill in present forecasts of hurricane structure and intensity may be attributed in part to deficiencies in the current prediction models: insufficient grid resolution, inadequate surface and boundary layer formulations, and the lack of full coupling to a dynamic ocean. The extreme high winds, intense rainfall, large ocean waves, and copious sea spray in hurricanes push the surface-exchange parameters for temperature, water vapor, and momentum into untested regimes. The recent modeling effort is to develop and test a fully coupled atmosphere-wave-ocean modeling system that is capable of resolving the eye and eyewall in a hurricane at ~1 km grid resolution. The new challenges for these very high resolution models are the corresponding physical representations at 1-km scale, including microphysics, sub-grid turbulence parameterization, atmospheric boundary layer, physical processes at the air-sea interface with surface waves among others. The lack of accurate initial conditions for high-resolution hurricane modeling presents another major challenge. Improvements in initial conditions rest on the use of more airborne and remotely sensed observations in high-resolution assimilation systems and on the application of advanced assimilation schemes to hurricanes. This study aimed to provide an overview of these new challenges using high-resolution model simulations of Hurricanes Isabel (2003), Frances (2004), Katrina and Rita (2005) that were observed extensively by two recent field programs, namely, the Coupled Boundary Layer Air-Sea Transfer (CBLAST)-Hurricane in 2003-2004 and the Hurricane Rainbands and Intensity Change Experiment (RAINEX) in 2005.

  2. Common high-resolution MMW scene generator

    NASA Astrophysics Data System (ADS)

    Saylor, Annie V.; McPherson, Dwight A.; Satterfield, H. DeWayne; Sholes, William J.; Mobley, Scott B.

    2001-08-01

    The development of a modularized millimeter wave (MMW) target and background high resolution scene generator is reported. The scene generator's underlying algorithms are applicable to both digital and real-time hardware-in-the-loop (HWIL) simulations. The scene generator will be configurable for a variety of MMW and multi-mode sensors employing state of the art signal processing techniques. At present, digital simulations for MMW and multi-mode sensor development and testing are custom-designed by the seeker vendor and are verified, validated, and operated by both the vendor and government in simulation-based acquisition. A typical competition may involve several vendors, each requiring high resolution target and background models for proper exercise of seeker algorithms. There is a need and desire by both the government and sensor vendors to eliminate costly re-design and re-development of digital simulations. Additional efficiencies are realized by assuring commonality between digital and HWIL simulation MMW scene generators, eliminating duplication of verification and validation efforts.

  3. High Resolution Acoustoelastic Measurements of Materials

    NASA Astrophysics Data System (ADS)

    McKenna, Mark; Guy, Samuel; Heyman, Joseph

    2006-11-01

    As materials become more complex, there is an increasing need for high resolution measurements to characterize strength and damage in the materials. Typically, the criterion for rejecting a part is based on the detection of a flaw of a specific size in a critical location. Interestingly, if a low stress field exists at the flaw site, the flaw may not grow over time. Similarly, in a part that shows no unacceptable indications, a high stress state may cause the flaw to quickly grow through the part leading to failure. In other cases, a controlled amount of stress (in a specific direction or type) is purposely added to the material to prevent flaw growth. Inspection time intervals are based knowing and controlling the stress environment to predict the flaw growth. Luna Innovations Incorporated has developed a high resolution ultrasonic instrument that can enhance the integrity of critical hardware by measuring changes in the stress state in a material. Knowledge of the stress state plus knowledge of crack sizes greatly improves structural engineers' capability of life prediction. System data will be shown for tests to stresses near holes in laboratory fabricated aircraft metal samples. Scans of the spatial distribution of stresses will be compared with finite element models of the structure.

  4. High-Resolution Shadowing of Transfer RNA

    PubMed Central

    Abermann, Reinhard J.; Yoshikami, Doju

    1972-01-01

    High-resolution shadowing with metals that melt at high temperatures was used to study macromolecules. Molecules of transfer RNA shadowed with tantalum-tungsten are readily visualized in an electron microscope. Mounting procedures for tRNA were perfected that reproducibly gave uniform distributions of both monomeric and dimeric tRNA particles, and allowed a statistical assessment of their gross shapes and sizes. Monomeric tRNA yielded a fairly homogeneous population of rod-shaped particles, with axial dimensions of about 40 × 85 Å. Dimers of yeast alanine tRNA held together by hydrogen bonds and dimers constructed by covalent linkage of the amino-acid acceptor (3′-) termini of monomers both gave slightly more heterogeneous populations of particles. Yet, their structures were also basically rod shaped, with their lengths ranging to about twice that of the monomer; this result indicates an end-to-end arrangement of the monomeric units within both dimers. These results suggest that the amino-acid acceptor terminus and the anticodon region are at the ends of the rod-shaped, dehydrated tRNA monomer visible by electron microscopy, consistent with the generally accepted view of tRNA structure in solution suggested by other workers using other methods. This study demonstrates that high-resolution shadowing with tantalum-tungsten provides a means to examine the three-dimensional structures of relatively small biological macromolecules. Images PMID:4504373

  5. Limiting liability via high resolution image processing

    SciTech Connect

    Greenwade, L.E.; Overlin, T.K.

    1996-12-31

    The utilization of high resolution image processing allows forensic analysts and visualization scientists to assist detectives by enhancing field photographs, and by providing the tools and training to increase the quality and usability of field photos. Through the use of digitized photographs and computerized enhancement software, field evidence can be obtained and processed as `evidence ready`, even in poor lighting and shadowed conditions or darkened rooms. These images, which are most often unusable when taken with standard camera equipment, can be shot in the worst of photographic condition and be processed as usable evidence. Visualization scientists have taken the use of digital photographic image processing and moved the process of crime scene photos into the technology age. The use of high resolution technology will assist law enforcement in making better use of crime scene photography and positive identification of prints. Valuable court room and investigation time can be saved and better served by this accurate, performance based process. Inconclusive evidence does not lead to convictions. Enhancement of the photographic capability helps solve one major problem with crime scene photos, that if taken with standard equipment and without the benefit of enhancement software would be inconclusive, thus allowing guilty parties to be set free due to lack of evidence.

  6. High resolution guided wave pipe inspection

    NASA Astrophysics Data System (ADS)

    Velichko, Alexander; Wilcox, Paul D.

    2009-03-01

    Commercial guided wave inspection systems provide rapid screening of pipes, but limited sizing capability for small defects. However, accurate detection and sizing of small defects is essential for assessing the integrity of inaccessible pipe regions where guided waves provide the only possible inspection mechanism. In this paper an array-based approach is presented that allows guided waves to be focused on both transmission and reception to produce a high resolution image of a length of pipe. In the image, it is shown that a signal to coherent noise ratio of over 40 dB with respect to the reflected signal from a free end of pipe can be obtained, even taking into account typical levels of experimental uncertainty in terms of transducer positioning, wave velocity etc. The combination of an image with high resolution and a 40 dB dynamic range enables the detection of very small defects. It also allows the in-plane shape of defects over a certain size to be observed directly. Simulations are used to estimate the detection and sizing capability of the system for crack-like defects. Results are presented from a prototype system that uses EMATs to fully focus pipe guided wave modes on both transmission and reception in a 12 inch diameter stainless steel pipe. The 40 dB signal to coherent noise ratio is obtained experimentally and a 2 mm diameter (0.08 wavelengths) half-thickness hole is shown to be detectable.

  7. High Resolution Spectroscopy to Support Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Venkataraman, Malathy Devi

    2003-01-01

    Spectroscopic parameters (such as line position, intensity, broadening and shifting coefficients and their temperature dependences, line mixing coefficients etc.) for various molecular species of atmospheric interest are determined. In order to achieve these results, infrared spectra of several molecular bands are obtained using high-resolution recording instruments such as tunable diode laser spectrometer and Fourier transform spectrometers. Using sophisticated analysis routines (Multispectrum nonlinear least squares technique) these high-resolution infrared spectra are processed to determine the various spectral line parameters that are cited above. Spectra were taken using the McMath-Pierce Fourier transform spectrometer (FTS) at the National Solar Observatory on Kitt Peak, Arizona as well as the Bruker FTS at the Pacific Northwest National Laboratory (PNNL) at Richland, Washington. Most of the spectra are acquired not only at room temperature, but also at several different cold temperatures. This procedure is necessary to study the variation of the spectral line parameters as a function of temperature in order to simulate the Earth's and other planetary atmospheric environments. Depending upon the strength or weakness of the various bands recorded and analyzed, the length(s) of the absorption cells in which the gas samples under study are kept varied from a few centimeters up to several meters and the sample temperatures varied from approximately +30 C to -63 C. Research on several infrared bands of various molecular species and their isotopomers are undertaken. Those studies are briefly described.

  8. High-Resolution PET Detector. Final report

    SciTech Connect

    Karp, Joel

    2014-03-26

    The objective of this project was to develop an understanding of the limits of performance for a high resolution PET detector using an approach based on continuous scintillation crystals rather than pixelated crystals. The overall goal was to design a high-resolution detector, which requires both high spatial resolution and high sensitivity for 511 keV gammas. Continuous scintillation detectors (Anger cameras) have been used extensively for both single-photon and PET scanners, however, these instruments were based on NaI(Tl) scintillators using relatively large, individual photo-multipliers. In this project we investigated the potential of this type of detector technology to achieve higher spatial resolution through the use of improved scintillator materials and photo-sensors, and modification of the detector surface to optimize the light response function.We achieved an average spatial resolution of 3-mm for a 25-mm thick, LYSO continuous detector using a maximum likelihood position algorithm and shallow slots cut into the entrance surface.

  9. High Resolution Camera for Mapping Titan Surface

    NASA Technical Reports Server (NTRS)

    Reinhardt, Bianca

    2011-01-01

    Titan, Saturn's largest moon, has a dense atmosphere and is the only object besides Earth to have stable liquids at its surface. The Cassini/Huygens mission has revealed the extraordinary breadth of geological processes shaping its surface. Further study requires high resolution imaging of the surface, which is restrained by light absorption by methane and scattering from aerosols. The Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft has demonstrated that Titan's surface can be observed within several windows in the near infrared, allowing us to process several regions in order to create a geological map and to determine the morphology. Specular reflections monitored on the lakes of the North Pole show little scattering at 5 microns, which, combined with the present study of Titan's northern pole area, refutes the paradigm that only radar can achieve high resolution mapping of the surface. The present data allowed us to monitor the evolution of lakes, to identify additional lakes at the Northern Pole, to examine Titan's hypothesis of non-synchronous rotation and to analyze the albedo of the North Pole surface. Future missions to Titan could carry a camera with 5 micron detectors and a carbon fiber radiator for weight reduction.

  10. High-Resolution Scintimammography: A Pilot Study

    SciTech Connect

    Rachel F. Brem; Joelle M. Schoonjans; Douglas A. Kieper; Stan Majewski; Steven Goodman; Cahid Civelek

    2002-07-01

    This study evaluated a novel high-resolution breast-specific gamma camera (HRBGC) for the detection of suggestive breast lesions. Methods: Fifty patients (with 58 breast lesions) for whom a scintimammogram was clinically indicated were prospectively evaluated with a general-purpose gamma camera and a novel HRBGC prototype. The results of conventional and high-resolution nuclear studies were prospectively classified as negative (normal or benign) or positive (suggestive or malignant) by 2 radiologists who were unaware of the mammographic and histologic results. All of the included lesions were confirmed by pathology. Results: There were 30 benign and 28 malignant lesions. The sensitivity for detection of breast cancer was 64.3% (18/28) with the conventional camera and 78.6% (22/28) with the HRBGC. The specificity with both systems was 93.3% (28/30). For the 18 nonpalpable lesions, sensitivity was 55.5% (10/18) and 72.2% (13/18) with the general-purpose camera and the HRBGC, respectively. For lesions 1 cm, 7 of 15 were detected with the general-purpose camera and 10 of 15 with the HRBGC. Four lesions (median size, 8.5 mm) were detected only with the HRBGC and were missed by the conventional camera. Conclusion: Evaluation of indeterminate breast lesions with an HRBGC results in improved sensitivity for the detection of cancer, with greater improvement shown for nonpalpable and 1-cm lesions.

  11. A quantitative structure activity relationships (QSAR) analysis of triarylmethane dye tracers

    NASA Astrophysics Data System (ADS)

    Mon, Jarai; Flury, Markus; Harsh, James B.

    2006-01-01

    Dyes are important hydrological tracers. Many different dyes have been proposed as optimal tracers, but none of these dyes can be considered an ideal water tracer. Some dyes are toxic and most sorb to subsurface materials. The objective of this study was to find the molecular structure of an optimal water tracer. We used QSAR to screen a large number of hypothetical molecules, belonging to the class of triarylmethane dyes, in regard to their sorption characteristics to a sandy soil. The QSAR model was based on experimental sorption data obtained from four triarylmethane dyes: C.I. Food Blue 2 (C.I. 42090; Brilliant Blue FCF), C.I. Food Green 3 (C.I. 42053; FD&C Green No. 3), C.I. Acid Blue 7 (C.I. 42080; ORCOacid Blue A 150%), and C.I. Acid Green 9 (C.I. 42100; ORCOacid Fast Green B). Sorption characteristics of the dyes to the sandy soil were expressed with the Langmuir isotherm. Our premise was that dye sorption can be reduced by attachment of sulfonic acid (SO 3) groups to the triarylmethane template. About 70 hypothetical dyes were created and QSAR were used to estimate sorption characteristics. The results indicated that both the position and the number of SO 3 groups affected dye sorption. Sorption decreased with increasing number of SO 3 groups attached to the molecule. Increasing the number of sulfonic acid groups also decreases the toxicity of the compounds. An optimal triarylmethane water tracer contains 4 to 6 SO 3 groups.

  12. Design of a High Resolution Hexapod Positioning Mechanism

    NASA Technical Reports Server (NTRS)

    Britt, Jamie

    2001-01-01

    This paper describes the development of a high resolution, six-degree of freedom positioning mechanism. This mechanism, based on the Stewart platform concept, was designed for use with the Developmental Comparative Active Optics Telescope Testbed (DCATT), a ground-based technology testbed for the Next Generation Space Telescope (NGST). The mechanism provides active control to the DCATT telescope's segmented primary mirror. Emphasis is on design decisions and technical challenges. Significant issues include undesirable motion properties of PZT-inchworm actuators, testing difficulties, dimensional stability, and use of advanced composite materials. Supporting test data from prototype mechanisms is presented.

  13. Design of a High Resolution Hexapod Positioning Mechanism

    NASA Technical Reports Server (NTRS)

    Britt, Jamie; Brodeur, Stephen J. (Technical Monitor)

    2001-01-01

    This paper describes the development of a high resolution, six-degree of freedom positioning mechanism. This mechanism, based on the Stewart platform concept, was designed for use with the Developmental Comparative Active Optics Telescope Testbed (DCATT), a ground-based technology testbed for the Next Generation Space Telescope (NGST). The mechanism provides active control to the DCATT telescope's segmented primary mirror. Emphasis is on design decisions and technical challenges. Significant issues include undesirable motion properties of PZT-inchworm actuators, testing difficulties, dimensional stability and use of advanced composite materials. Supporting test data from prototype mechanisms is presented.

  14. A high resolution history of the El Niño - Southern Oscillation and of the solar activity during the Late Glacial - Early Holocene in the subtropical Andean region.

    NASA Astrophysics Data System (ADS)

    Giralt, S.; Schimmel, M.; Hernández, A.; Bao, R.; Valero-Garcés, B. L.; Sáez, A.; Pueyo, J. J.

    2009-04-01

    High-resolution laminated lacustrine sediments are excellent archives of the past hydrological changes and they provide valuable insights about the climatic processes that trigger these changes. The paleoclimatic records located in the Southern Hemisphere are fundamental for understanding the evolution of the El Niño - Southern Oscillation (ENSO) since this climatic phenomena is the main cause of droughts and floods in many areas of South America and other regions of the world, like Spain and Egypt. Available regional paleoclimate reconstructions show that modern climatic patterns in South America were established during the Late Holocene. The laminated sediments of Lago Chungará (18° 15' S - 69° 10' W, 4520 m a.s.l., Chilean altiplano) have allowed us to characterize the evolution of this climatic phenomena for the transition Late Glacial - Early Holocene (12,300 - 9,500 calendar years BP) as well as its relationship with other climate forcings, namely the solar activity. The studied sediments correspond to the lowermost 2.4 m of 8 m long Kullemberg cores recovered from this lake. These sediments are mainly made up of greenish and whitish laminae and thin layers constituted by diatomaceous oozes with carbonates and organic matter, arranged in rhythms and cycles. X-ray fluorescence (XRF) (Al, Si, S, K, Ca, Ti, Mn, Fe, Rb, Sr, Zn, Sb and Ba) analyses, total organic carbon (TOC), total carbon (TC), x-ray diffraction (XRD), biogenic silica, stable isotopes (delta18O and delta13C) on carbonates and on diatoms (delta18O) and magnetic susceptibility were determined in order to characterize the sediments of Lago Chungará. Previous statistical studies (cluster and Principal Component Analyses (PCA)) were used to disentangle the paleoclimatic signal from the other ones (volcanic and tectonic). The chronological model framework was built using 6 radiocarbon dates, allowing us to establish that laminated couplets were deposited on a pluriannual basis. These couplets are

  15. Clementine High Resolution Camera Mosaicking Project

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This report constitutes the final report for NASA Contract NASW-5054. This project processed Clementine I high resolution images of the Moon, mosaicked these images together, and created a 22-disk set of compact disk read-only memory (CD-ROM) volumes. The mosaics were produced through semi-automated registration and calibration of the high resolution (HiRes) camera's data against the geometrically and photometrically controlled Ultraviolet/Visible (UV/Vis) Basemap Mosaic produced by the US Geological Survey (USGS). The HiRes mosaics were compiled from non-uniformity corrected, 750 nanometer ("D") filter high resolution nadir-looking observations. The images were spatially warped using the sinusoidal equal-area projection at a scale of 20 m/pixel for sub-polar mosaics (below 80 deg. latitude) and using the stereographic projection at a scale of 30 m/pixel for polar mosaics. Only images with emission angles less than approximately 50 were used. Images from non-mapping cross-track slews, which tended to have large SPICE errors, were generally omitted. The locations of the resulting image population were found to be offset from the UV/Vis basemap by up to 13 km (0.4 deg.). Geometric control was taken from the 100 m/pixel global and 150 m/pixel polar USGS Clementine Basemap Mosaics compiled from the 750 nm Ultraviolet/Visible Clementine imaging system. Radiometric calibration was achieved by removing the image nonuniformity dominated by the HiRes system's light intensifier. Also provided are offset and scale factors, achieved by a fit of the HiRes data to the corresponding photometrically calibrated UV/Vis basemap, that approximately transform the 8-bit HiRes data to photometric units. The sub-polar mosaics are divided into tiles that cover approximately 1.75 deg. of latitude and span the longitude range of the mosaicked frames. Images from a given orbit are map projected using the orbit's nominal central latitude. Polar mosaics are tiled into squares 2250 pixels on a

  16. High Resolution Powder Diffraction and Structure Determination

    SciTech Connect

    Cox, D. E.

    1999-04-23

    It is clear that high-resolution synchrotrons X-ray powder diffraction is a very powerful and convenient tool for material characterization and structure determination. Most investigations to date have been carried out under ambient conditions and have focused on structure solution and refinement. The application of high-resolution techniques to increasingly complex structures will certainly represent an important part of future studies, and it has been seen how ab initio solution of structures with perhaps 100 atoms in the asymmetric unit is within the realms of possibility. However, the ease with which temperature-dependence measurements can be made combined with improvements in the technology of position-sensitive detectors will undoubtedly stimulate precise in situ structural studies of phase transitions and related phenomena. One challenge in this area will be to develop high-resolution techniques for ultra-high pressure investigations in diamond anvil cells. This will require highly focused beams and very precise collimation in front of the cell down to dimensions of 50 {micro}m or less. Anomalous scattering offers many interesting possibilities as well. As a means of enhancing scattering contrast it has applications not only to the determination of cation distribution in mixed systems such as the superconducting oxides discussed in Section 9.5.3, but also to the location of specific cations in partially occupied sites, such as the extra-framework positions in zeolites, for example. Another possible application is to provide phasing information for ab initio structure solution. Finally, the precise determination of f as a function of energy through an absorption edge can provide useful information about cation oxidation states, particularly in conjunction with XANES data. In contrast to many experiments at a synchrotron facility, powder diffraction is a relatively simple and user-friendly technique, and most of the procedures and software for data analysis

  17. Radio active galactic nuclei in galaxy clusters: Feedback, merger signatures, and cluster tracers

    NASA Astrophysics Data System (ADS)

    Paterno-Mahler, Rachel Beth

    Galaxy clusters, the largest gravitationally-bound structures in the universe, are composed of 50-1000s of galaxies, hot X-ray emitting gas, and dark matter. They grow in size over time through cluster and group mergers. The merger history of a cluster can be imprinted on the hot gas, known as the intracluster medium (ICM). Merger signatures include shocks, cold fronts, and sloshing of the ICM, which can form spiral structures. Some clusters host double-lobed radio sources driven by active galactic nuclei (AGN). First, I will present a study of the galaxy cluster Abell 2029, which is very relaxed on large scales and has one of the largest continuous sloshing spirals yet observed in the X-ray, extending outward approximately 400 kpc. The sloshing gas interacts with the southern lobe of the radio galaxy, causing it to bend. Energy injection from the AGN is insufficient to offset cooling. The sloshing spiral may be an important additional mechanism in preventing large amounts of gas from cooling to very low temperatures. Next, I will present a study of Abell 98, a triple system currently undergoing a merger. I will discuss the merger history, and show that it is causing a shock. The central subcluster hosts a double-lobed AGN, which is evacuating a cavity in the ICM. Understanding the physical processes that affect the ICM is important for determining the mass of clusters, which in turn affects our calculations of cosmological parameters. To further constrain these parameters, as well as models of galaxy evolution, it is important to use a large sample of galaxy clusters over a range of masses and redshifts. Bent, double-lobed radio sources can potentially act as tracers of galaxy clusters over wide ranges of these parameters. I examine how efficient bent radio sources are at tracing high-redshift (z>0.7) clusters. Out of 646 sources in our high-redshift Clusters Occupied by Bent Radio AGN (COBRA) sample, 282 are candidate new, distant clusters of galaxies based on

  18. High resolution electron crystallography of protein molecules

    SciTech Connect

    Glaeser, R.M. |; Downing, K.H.

    1993-06-01

    Electron diffraction data and high resolution images can now be used to obtain accurate, three-dimensional density maps of biological macromolecules. These density maps can be interpreted by building an atomic-resolution model of the structure into the experimental density. The Cowley-Moodie formalism of dynamical diffraction theory has been used to validate the use of kinematic diffraction theory, strictly the weak phase object approximation, in producing such 3-D density maps. Further improvements in the preparation of very flat specimens and in the retention of diffraction to a resolution of 0.2 nm or better could result in electron crystallography becoming as important a technique as x-ray crystallography currently is for the field of structural molecular biology.

  19. Computer synthesis of high resolution electron micrographs

    NASA Technical Reports Server (NTRS)

    Nathan, R.

    1976-01-01

    Specimen damage, spherical aberration, low contrast and noisy sensors combine to prevent direct atomic viewing in a conventional electron microscope. The paper describes two methods for obtaining ultra-high resolution in biological specimens under the electron microscope. The first method assumes the physical limits of the electron objective lens and uses a series of dark field images of biological crystals to obtain direct information on the phases of the Fourier diffraction maxima; this information is used in an appropriate computer to synthesize a large aperture lens for a 1-A resolution. The second method assumes there is sufficient amplitude scatter from images recorded in focus which can be utilized with a sensitive densitometer and computer contrast stretching to yield fine structure image details. Cancer virus characterization is discussed as an illustrative example. Numerous photographs supplement the text.

  20. High Resolution, High Frame Rate Video Technology

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Papers and working group summaries presented at the High Resolution, High Frame Rate Video (HHV) Workshop are compiled. HHV system is intended for future use on the Space Shuttle and Space Station Freedom. The Workshop was held for the dual purpose of: (1) allowing potential scientific users to assess the utility of the proposed system for monitoring microgravity science experiments; and (2) letting technical experts from industry recommend improvements to the proposed near-term HHV system. The following topics are covered: (1) State of the art in the video system performance; (2) Development plan for the HHV system; (3) Advanced technology for image gathering, coding, and processing; (4) Data compression applied to HHV; (5) Data transmission networks; and (6) Results of the users' requirements survey conducted by NASA.

  1. A simple, high efficiency, high resolution spectropolarimeter

    NASA Astrophysics Data System (ADS)

    Barden, Samuel C.

    2012-09-01

    A simple concept is described that uses volume phase holographic gratings as polarizing dispersers for a high efficiency, high resolution spectropolarimeter. Although the idea has previously been mentioned in the literature as possible, such a concept has not been explored in detail. Performance analysis is presented for a VPHG spectropolarimeter concept that could be utilized for both solar and night-time astronomy. Instrumental peak efficiency can approach 100% with spectral dispersions permitting R~200,000 spectral resolution with diffraction limited telescopes. The instrument has 3-channels: two dispersed image planes with orthogonal polarization and an undispersed image plane. The concept has a range of versatility where it could be configured (with appropriate half-wave plates) for slit-fed spectroscopy or without slits for snapshot/hyperspectral/tomographic spectroscopic imaging. Multiplex gratings could also be used for the simultaneous recording of two separate spectral bands or multiple instruments could be daisy chained with beam splitters for further spectral coverage.

  2. High-resolution spectrometer for atmospheric studies

    NASA Astrophysics Data System (ADS)

    Di Carlo, Piero; Barone, Massimiliano; D'Altorio, Alfonso; Dari-Salisburgo, Cesare; Pietropaolo, Ermanno

    2009-08-01

    A high-resolution spectrometer (0.0014 nm at 313 nm) has been developed at the University of L'Aquila (Italy) for atmospheric spectroscopic studies. The layout, optics and software for the instrument control are described. Measurements of the mercury low-pressure lamp lines from 200 to 600 nm show the high performances of the spectrometer. Laboratory measurements of OH and NO2 spectrums demonstrate that the system could be used for cross-section measurements and to detect these species in the atmosphere. The first atmospheric application of the system was the observation of direct solar and sky spectrums that shows a filling-in of the sky lines due to rotational Raman scattering. The measurements have been done with clear and cloudy sky and in both there was a strong dependence of the filling-in from the solar zenith angle whereas no dependence from the wavelengths was evident at low solar zenith angles (less than 85°).

  3. Characterization of a high resolution transmission grating

    NASA Astrophysics Data System (ADS)

    Desauté, P.; Merdji, H.; Greiner, V.; Missalla, T.; Chenais-Popovics, C.; Troussel, P.

    2000-01-01

    Three 5000 lines/mm gold transmission gratings have been tested with the radiation from the Super-ACO synchrotron in the range 250 eV< E<850 eV. Typical results for the spectral dependence of the grating efficiency at different diffraction orders are presented. This grating theoretically built to have no second order exhibits second order as high as 15-20% of first order. The very thin 5000 L/mm gratings are supported by a larger grid which perturbs the recorded data by separating each order in three peaks. Fraunhofer diffraction of the support grid has been modelled and can explain this effect. The high resolution gratings were used to measure the harmonics of the beamline monochromator grating (550 L/mm) and to measure the emission and absorption of laser-produced plasmas in the XUV range.

  4. Improved methods for high resolution electron microscopy

    NASA Astrophysics Data System (ADS)

    Taylor, J. R.

    1987-04-01

    Existing methods of making support films for high resolution transmission electron microscopy are investigated and novel methods are developed. Existing methods of fabricating fenestrated, metal reinforced specimen supports (microgrids) are evaluated for their potential to reduce beam induced movement of monolamellar crystals of C44H90 paraffin supported on thin carbon films. Improved methods of producing hydrophobic carbon films by vacuum evaporation, and improved methods of depositing well ordered monolamellar paraffin crystals on carbon films are developed. A novel technique for vacuum evaporation of metals is described which is used to reinforce microgrids. A technique is also developed to bond thin carbon films to microgrids with a polymer bonding agent. Unique biochemical methods are described to accomplish site specific covalent modification of membrane proteins. Protocols are given which covalently convert the carboxy terminus of papain cleaved bacteriorhodopsin to a free thiol.

  5. High resolution solar X-ray studies

    NASA Technical Reports Server (NTRS)

    Blake, R. L.

    1974-01-01

    Two high resolution solar X-ray payloads and their launches on Aerobee rockets with pointing system are described. The payloads included 5 to 25A X-ray spectrometers, multiaperture X-ray cameras, and command box attitude control inflight by means of a television image radioed to ground. Spatial resolution ranged from five arc minutes to ten arc seconds and spectral resolution ranged from 500 to 3000. Several laboratory tasks were completed in order to achieve the desired resolution. These included (1) development of techniques to align grid collimators, (2) studies of the spectrometric properties of crystals, (3) measurements of the absorption coefficients of various materials used in X-ray spectrometers, (4) evaluation of the performance of multiaperture cameras, and (5) development of facilities.

  6. Ultra-high resolution computed tomography imaging

    DOEpatents

    Paulus, Michael J.; Sari-Sarraf, Hamed; Tobin, Jr., Kenneth William; Gleason, Shaun S.; Thomas, Jr., Clarence E.

    2002-01-01

    A method for ultra-high resolution computed tomography imaging, comprising the steps of: focusing a high energy particle beam, for example x-rays or gamma-rays, onto a target object; acquiring a 2-dimensional projection data set representative of the target object; generating a corrected projection data set by applying a deconvolution algorithm, having an experimentally determined a transfer function, to the 2-dimensional data set; storing the corrected projection data set; incrementally rotating the target object through an angle of approximately 180.degree., and after each the incremental rotation, repeating the radiating, acquiring, generating and storing steps; and, after the rotating step, applying a cone-beam algorithm, for example a modified tomographic reconstruction algorithm, to the corrected projection data sets to generate a 3-dimensional image. The size of the spot focus of the beam is reduced to not greater than approximately 1 micron, and even to not greater than approximately 0.5 microns.

  7. High-resolution adaptive spiking sonar.

    PubMed

    Alvarez, Fernando J; Kuc, Roman

    2009-05-01

    A new sonar system based on the conventional 6500 ranging module is presented that generates a sequence of spikes whose temporal density is related to the strength of the received echo. This system notably improves the resolution of a previous system by shortening the discharge cycle of the integrator included in the module. The operation is controlled by a PIC18F452 device, which can adapt the duration of the discharge to changing features of the echo, providing the system with a novel adaptive behavior. The performance of the new sensor is characterized and compared with that of the previous system by performing rotational scans of simple objects with different reflecting strengths. Some applications are suggested that exploit the high resolution and adaptability of this sensor. PMID:19473919

  8. High resolution analysis of satellite gradiometry

    NASA Technical Reports Server (NTRS)

    Colombo, O. L.

    1989-01-01

    Satellite gravity gradiometry is a technique now under development which, by the middle of the next decade, may be used for the high resolution charting from space of the gravity field of the earth and, afterwards, of other planets. Some data analysis schemes are reviewed for getting detailed gravity maps from gradiometry on both a global and a local basis. It also presents estimates of the likely accuracies of such maps, in terms of normalized spherical harmonics expansions, both using gradiometry alone and in combination with data from a Global Positioning System (GPS) receiver carried on the same spacecraft. It compares these accuracies with those of current and future maps obtained from other data (conventional tracking, satellite-satellite tracking, etc.), and also with the spectra of various signals of geophysical interest.

  9. High-Resolution Broadband Spectral Interferometry

    SciTech Connect

    Erskine, D J; Edelstein, J

    2002-08-09

    We demonstrate solar spectra from a novel interferometric method for compact broadband high-resolution spectroscopy. The spectral interferometer (SI) is a hybrid instrument that uses a spectrometer to externally disperse the output of a fixed-delay interferometer. It also has been called an externally dispersed interferometer (EDI). The interferometer can be used with linear spectrometers for imaging spectroscopy or with echelle spectrometers for very broad-band coverage. EDI's heterodyning technique enhances the spectrometer's response to high spectral-density features, increasing the effective resolution by factors of several while retaining its bandwidth. The method is extremely robust to instrumental insults such as focal spot size or displacement. The EDI uses no moving parts, such as purely interferometric FTS spectrometers, and can cover a much wider simultaneous bandpass than other internally dispersed interferometers (e.g. HHS or SHS).

  10. Limits of simulation based high resolution EBSD.

    PubMed

    Alkorta, Jon

    2013-08-01

    High resolution electron backscattered diffraction (HREBSD) is a novel technique for a relative determination of both orientation and stress state in crystals through digital image correlation techniques. Recent works have tried to use simulated EBSD patterns as reference patterns to achieve the absolute orientation and stress state of crystals. However, a precise calibration of the pattern centre location is needed to avoid the occurrence of phantom stresses. A careful analysis of the projective transformation involved in the formation of EBSD patterns has permitted to understand these phantom stresses. This geometrical analysis has been confirmed by numerical simulations. The results indicate that certain combinations of crystal strain states and sample locations (pattern centre locations) lead to virtually identical EBSD patterns. This ambiguity makes the problem of solving the absolute stress state of a crystal unfeasible in a single-detector configuration. PMID:23676453

  11. Constructing a WISE High Resolution Galaxy Atlas

    NASA Technical Reports Server (NTRS)

    Jarrett, T. H.; Masci, F.; Tsai, C. W.; Petty, S.; Cluver, M.; Assef, Roberto J.; Benford, D.; Blain, A.; Bridge, C.; Donoso, E.; Eisenhardt, P.; Fowler, J.; Koribalski, B.; Lake, S.; Neill, James D.; Seibert, M.; Stanford, S.; Wright, E.

    2012-01-01

    After eight months of continuous observations, the Wide-field Infrared Survey Explorer (WISE) mapped the entire sky at 3.4 micron, 4.6 micron, 12 micron, and 22 micron. We have begun a dedicated WISE High Resolution Galaxy Atlas project to fully characterize large, nearby galaxies and produce a legacy image atlas and source catalog. Here we summarize the deconvolution techniques used to significantly improve the spatial resolution of WISE imaging, specifically designed to study the internal anatomy of nearby galaxies. As a case study, we present results for the galaxy NGC 1566, comparing the WISE enhanced-resolution image processing to that of Spitzer, Galaxy Evolution Explorer, and ground-based imaging. This is the first paper in a two-part series; results for a larger sample of nearby galaxies are presented in the second paper.

  12. High-resolution scanning hall probe microscopy

    NASA Astrophysics Data System (ADS)

    Hicks, C. W.; Guikema, J. W.; Zeldov, E.

    2005-03-01

    Scanning hall sensors can be used to directly image magnetic fields at surfaces. They offer high resolution, high sensitivity, operability from cryogenic to room temperature, and linearity. We have fabricated hall sensors on GaAs / Al0.35Ga0.65As and GaAs / Al0.3Ga0.7As heterostructures, one containing a 2D electron gas 40 nanometers below the surface and another 140nm below the surface, as well as an In0.5Al0.5As / GaSb / AlSb / InAs heterostructure containing a 2DEG 21nm below the surface. The sensitive areas of our probes range from microns to 60nm on a side. We report on the field sensitivities of the probes and their spatial resolution in a scanning configuration.

  13. Improved methods for high resolution electron microscopy

    SciTech Connect

    Taylor, J.R.

    1987-04-01

    Existing methods of making support films for high resolution transmission electron microscopy are investigated and novel methods are developed. Existing methods of fabricating fenestrated, metal reinforced specimen supports (microgrids) are evaluated for their potential to reduce beam induced movement of monolamellar crystals of C/sub 44/H/sub 90/ paraffin supported on thin carbon films. Improved methods of producing hydrophobic carbon films by vacuum evaporation, and improved methods of depositing well ordered monolamellar paraffin crystals on carbon films are developed. A novel technique for vacuum evaporation of metals is described which is used to reinforce microgrids. A technique is also developed to bond thin carbon films to microgrids with a polymer bonding agent. Unique biochemical methods are described to accomplish site specific covalent modification of membrane proteins. Protocols are given which covalently convert the carboxy terminus of papain cleaved bacteriorhodopsin to a free thiol. 53 refs., 19 figs., 1 tab.

  14. Information extraction from high resolution satellite images

    NASA Astrophysics Data System (ADS)

    Yang, Haiping; Luo, Jiancheng; Shen, Zhanfeng; Xia, Liegang

    2014-11-01

    Information extracted from high resolution satellite images, such as roads, buildings, water and vegetation, has a wide range of applications in disaster assessment and environmental monitoring. At present, object oriented supervised learning is usually used in the objects identification from the high spatial resolution satellite images. In classical ways, we have to label some regions of interests from every image to be classified at first, which is labor intensive. In this paper, we build a feature base for information extraction in order to reduce the labeling efforts. The features stored are regulated and labeled. The labeled samples for a new coming image can be selected from the feature base. And the experiments are taken on GF-1 and ZY-3 images. The results show the feasibility of the feature base for image interpretation.

  15. Pyramidal fractal dimension for high resolution images

    NASA Astrophysics Data System (ADS)

    Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

    2016-07-01

    Fractal analysis (FA) should be able to yield reliable and fast results for high-resolution digital images to be applicable in fields that require immediate outcomes. Triggered by an efficient implementation of FA for binary images, we present three new approaches for fractal dimension (D) estimation of images that utilize image pyramids, namely, the pyramid triangular prism, the pyramid gradient, and the pyramid differences method (PTPM, PGM, PDM). We evaluated the performance of the three new and five standard techniques when applied to images with sizes up to 8192 × 8192 pixels. By using artificial fractal images created by three different generator models as ground truth, we determined the scale ranges with minimum deviations between estimation and theory. All pyramidal methods (PM) resulted in reasonable D values for images of all generator models. Especially, for images with sizes ≥1024 ×1024 pixels, the PMs are superior to the investigated standard approaches in terms of accuracy and computation time. A measure for the possibility to differentiate images with different intrinsic D values did show not only that the PMs are well suited for all investigated image sizes, and preferable to standard methods especially for larger images, but also that results of standard D estimation techniques are strongly influenced by the image size. Fastest results were obtained with the PDM and PGM, followed by the PTPM. In terms of absolute D values best performing standard methods were magnitudes slower than the PMs. Concluding, the new PMs yield high quality results in short computation times and are therefore eligible methods for fast FA of high-resolution images.

  16. High-resolution simulation of field emission

    SciTech Connect

    Herrmannsfeldt, W.B. ); Becker, R. ); Brodie, I.; Rosengreen, A.; Spindt, C.A. )

    1990-03-01

    High-resolution simulations of field emission electron sources have been made using the electron optics program EGN2. Electron emission distributions are made using the Fowler-Nordheim equation. Mesh resolution in the range of 1-5 {angstrom} is required to adequately model surface details that can result in emission currents in the range found experimentally. A typical problem starts with mechanical details with dimensions of about 1{mu}. To achieve high resolution a new boundary is defined by the tip, a nearby equipotential line, and a pair of field lines. The field lines (one of which is normally the axis of symmetry) define Neumann boundaries. This new boundary is then used by the boundary preprocessor POLYGON to create an enlarged version of the problem, typically by a factor of ten. This process can be repeated until adequate resolution is obtained to simulate surface details, such as microprotusion, that could sufficiently enhance the surface electric fields and cause field emission. When simulating experimental conditions under which emission of several microamperes per tip were observed, it was found that both a locally reduced work function and a surface protrusion were needed to duplicate the experimental results. If only a local region of reduced work function is used, the area involved and the extent of the reduction both need to be very large to reproduce the emission. If only a surface protrusion is used, it is possible to get the observed emission current with a reasonable protrusion of length a few times radius, but then the resulting beam spreads over a very large solid angle due to the strong local radial electric fields. 8 refs., 14 figs., 1 tab.

  17. Pyramidal fractal dimension for high resolution images.

    PubMed

    Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

    2016-07-01

    Fractal analysis (FA) should be able to yield reliable and fast results for high-resolution digital images to be applicable in fields that require immediate outcomes. Triggered by an efficient implementation of FA for binary images, we present three new approaches for fractal dimension (D) estimation of images that utilize image pyramids, namely, the pyramid triangular prism, the pyramid gradient, and the pyramid differences method (PTPM, PGM, PDM). We evaluated the performance of the three new and five standard techniques when applied to images with sizes up to 8192 × 8192 pixels. By using artificial fractal images created by three different generator models as ground truth, we determined the scale ranges with minimum deviations between estimation and theory. All pyramidal methods (PM) resulted in reasonable D values for images of all generator models. Especially, for images with sizes ≥1024×1024 pixels, the PMs are superior to the investigated standard approaches in terms of accuracy and computation time. A measure for the possibility to differentiate images with different intrinsic D values did show not only that the PMs are well suited for all investigated image sizes, and preferable to standard methods especially for larger images, but also that results of standard D estimation techniques are strongly influenced by the image size. Fastest results were obtained with the PDM and PGM, followed by the PTPM. In terms of absolute D values best performing standard methods were magnitudes slower than the PMs. Concluding, the new PMs yield high quality results in short computation times and are therefore eligible methods for fast FA of high-resolution images. PMID:27475069

  18. Retrieving mesospheric winds and gravity waves using high resolution radar measurements of polar mesospheric summer echoes with MAARSY

    NASA Astrophysics Data System (ADS)

    Stober, G.; Sommer, S.; Schult, C.; Chau, J. L.; Latteck, R.

    2013-12-01

    The Middle Atmosphere Alomar Radar System (MAARSY) located at the northern Norwegian island of Andøya (69.3 ° N, 16° E) observes polar mesosphere summer echoes (PMSE) on a regular basis. This backscatter turned out to be an ideal tracer of atmospheric dynamics and to investigate the wind field at the mesosphere/lower thermosphere (MLT) at high spatial and temporal scales. MAARSY is dedicated to explore the polar mesosphere at such high resolution and employs an active phased array antenna with the capability to steer the beam on a pulse-to-pulse basis, which permits to perform systematic scanning of PMSE and to investigate the horizontal structure of the backscatter. The radar also uses a 16 channel receiver system for interferometric applications e.g. mean angle of arrival analysis or coherent radar imaging. Here we present measurements using these features of MAARSY to study the wind field at the MLT applying sophisticated wind analysis algorithms such as velocity azimuth display or volume velocity processing to derive gravity wave parameters such as horizontal wave length, phase speed and propagation direction. Further, we compare the interferometrically corrected and uncorrected wind measurements to emphasize the importance to account for likely edge effects using PMSE as tracer of the dynamics. The observations indicate huge deviations from the nominal beam pointing direction at the upper and lower edges of the PMSE altering the wind analysis.

  19. Clickstream data yields high-resolution maps of science

    SciTech Connect

    Bollen, Johan; Van De Sompel, Herbert; Hagberg, Aric; Bettencourt, Luis; Chute, Ryan; Rodriguez, Marko A; Balakireva, Lyudmila

    2009-01-01

    Intricate maps of science have been created from citation data to visualize the structure of scientific activity. However, most scientific publications are now accessed online. Scholarly web portals record detailed log data at a scale that exceeds the number of all existing citations combined. Such log data is recorded immediately upon publication and keeps track of the sequences of user requests (clickstreams) that are issued by a variety of users across many different domains. Given these advantagees of log datasets over citation data, we investigate whether they can produce high-resolution, more current maps of science.

  20. A High Resolution Microprobe Study of EETA79001 Lithology C

    NASA Technical Reports Server (NTRS)

    Schrader, Christian M.; Cohen, B. A.; Donovan, J. J.; Vicenzi, E. P.

    2010-01-01

    Antarctic meteorite EETA79001 has received substantial attention for possibly containing a component of Martian soil in its impact glass (Lithology C) [1]. The composition of Martian soil can illuminate near-surface processes such as impact gardening [2] and hydrothermal and volcanic activity [3,4]. Impact melts in meteorites represent our most direct samples of Martian regolith. We present the initial findings from a high-resolution electron microprobe study of Lithology C from Martian meteorite EETA79001. As this study develops we aim to extract details of a potential soil composition and to examine Martian surface processes using elemental ratios and correlations.

  1. High-Resolution Geologic Mapping in East Candor Chasma: 2016 Status Report

    NASA Astrophysics Data System (ADS)

    Okubo, C. H.

    2016-06-01

    This abstract summarizes current results and planned activities from an ongoing initiative to construct a series of high-resolution structural and geologic maps in the east Candor Chasma region of Valles Marineris, Mars.

  2. Crusta: Visualizing High-resolution Global Data

    NASA Astrophysics Data System (ADS)

    Bernardin, T. S.; Kreylos, O.; Bowles, C. J.; Cowgill, E.; Hamann, B.; Kellogg, L. H.

    2009-12-01

    Virtual globes have become indispensable tools for visualizing, understanding and presenting data from Earth and other planetary bodies. The scientific community has invested much effort into exploiting existing globes to their fullest potential by refining and adapting their capabilities to better satisfy specific needs. For example, Google Earth provides users with the ability to view hillshade images derived from airborne LiDAR data such as the 2007 Northern California GeoEarthScope data. However, because most available globes were not designed with the specific needs of geoscientists in mind, shortcomings are becoming increasingly evident in geoscience applications such as terrain visualization. In particular, earth scientists struggle to visualize digital elevation models with both high spatial resolution (0.5 - 1 square meters per sample) and large extent (>2000 square kilometers), such as those obtained with airborne LiDAR. To address the specific earth science need of real-time terrain visualization of LiDAR data, we are developing Crusta as part of a close collaboration involving earth and computer scientists. Crusta is a new virtual globe that differs from widely used globes by both providing accurate global data representation and the ability to easily visualize custom topographic and image data. As a result, Crusta enables real-time, interactive visualization of high resolution digital elevation data spanning thousands of square kilometers, such as the complete 2007 Northern California GeoEarthScope airborne LiDAR data set. To implement an accurate data representation and avoid distortion of the display at the poles, where other projections have singularities, Crusta represents the globe as a thirty-sided polyhedron. Each side of this polyhedron can be subdivided to an arbitrarily fine grid on the surface of the globe, which allows Crusta to accommodate input data of arbitrary resolution ranging from global (e.g., Blue Marble) to local (e.g., a tripod

  3. Efficient Compression of High Resolution Climate Data

    NASA Astrophysics Data System (ADS)

    Yin, J.; Schuchardt, K. L.

    2011-12-01

    resolution climate data can be massive. Those data can consume a huge amount of disk space for storage, incur significant overhead for outputting data during simulation, introduce high latency for visualization and analysis, and may even make interactive visualization and analysis impossible given the limit of the data that a conventional cluster can handle. These problems can be alleviated by with effective and efficient data compression techniques. Even though HDF5 format supports compression, previous work has mainly focused on employ traditional general purpose compression schemes such as dictionary coder and block sorting based compression scheme. Those compression schemes mainly focus on encoding repeated byte sequences efficiently and are not well suitable for compressing climate data consist mainly of distinguished float point numbers. We plan to select and customize our compression schemes according to the characteristics of high-resolution climate data. One observation on high resolution climate data is that as the resolution become higher, values of various climate variables such as temperature and pressure, become closer in nearby cells. This provides excellent opportunities for predication-based compression schemes. We have performed a preliminary estimation of compression ratios of a very simple minded predication-based compression ratio in which we compute the difference between current float point number with previous float point number and then encoding the exponent and significance part of the float point number with entropy-based compression scheme. Our results show that we can achieve higher compression ratios between 2 and 3 in lossless compression, which is significantly higher than traditional compression algorithms. We have also developed lossy compression with our techniques. We can achive orders of magnitude data reduction while ensure error bounds. Moreover, our compression scheme is much more efficient and introduces much less overhead

  4. Superconducting High Resolution Fast-Neutron Spectrometers

    SciTech Connect

    Hau, I D

    2006-05-25

    Superconducting high resolution fast-neutron calorimetric spectrometers based on {sup 6}LiF and TiB{sub 2} absorbers have been developed. These novel cryogenic spectrometers measure the temperature rise produced in exothermal (n, {alpha}) reactions with fast neutrons in {sup 6}Li and {sup 10}B-loaded materials with heat capacity C operating at temperatures T close to 0.1 K. Temperature variations on the order of 0.5 mK are measured with a Mo/Cu thin film multilayer operated in the transition region between its superconducting and its normal state. The advantage of calorimetry for high resolution spectroscopy is due to the small phonon excitation energies k{sub B}T on the order of {mu}eV that serve as signal carriers, resulting in an energy resolution {Delta}E {approx} (k{sub B}T{sup 2}C){sup 1/2}, which can be well below 10 keV. An energy resolution of 5.5 keV has been obtained with a Mo/Cu superconducting sensor and a TiB{sub 2} absorber using thermal neutrons from a {sup 252}Cf neutron source. This resolution is sufficient to observe the effect of recoil nuclei broadening in neutron spectra, which has been related to the lifetime of the first excited state in {sup 7}Li. Fast-neutron spectra obtained with a {sup 6}Li-enriched LiF absorber show an energy resolution of 16 keV FWHM, and a response in agreement with the {sup 6}Li(n, {alpha}){sup 3}H reaction cross section and Monte Carlo simulations for energies up to several MeV. The energy resolution of order of a few keV makes this novel instrument applicable to fast-neutron transmission spectroscopy based on the unique elemental signature provided by the neutron absorption and scattering resonances. The optimization of the energy resolution based on analytical and numerical models of the detector response is discussed in the context of these applications.

  5. Active ion tracer experiments attempted in conjunction with the ion composition experiment on GEOS-2

    NASA Astrophysics Data System (ADS)

    Young, D. T.

    It is pointed out that to date six ion injection/tracer experiments have been attempted in conjunction with the GEOS-2 Ion Composition Experiment: three rocket borne Ba shaped-charge releases (Porcupine 3 and 4 and Ba-GEOS), one Li release, and two periods of operation of the Xe(+) accelerator on the SCATHA satellite. The characteristics of each of these six releases are outlined, and upper limits are placed on possible ion fluxes reaching GEOS-2. The order of magnitude of ion fluxes to be expected from each release is estimated, and it is shown that three of the experiments had no real chance of succeeding in the first place.

  6. High resolution spectrograph for the Space Telescope

    NASA Technical Reports Server (NTRS)

    Brandt, J. C.; Boggess, A.; Heap, S. R.; Maran, S. P.; Smith, A. M.; Beaver, E. A.; Bottema, M.; Hutchings, J. B.; Jura, M. A.; Linsky, J. L.

    1979-01-01

    The high resolution spectrograph (HRS) for ultraviolet astronomy with the Space Telescope will provide a spectral resolution of approximately 120,000 over a nominal wavelength range of 110-320 nm, together with a spatial resolution of about 0.25 arc seconds. The two detectors will consist of 512-element Digicons with cesium telluride and cesium iodide photocathodes, respectively. Photoelectrons in transit between the photocathodes and the diodes within the Digicons can be deflected in two axes with 12-bit resolution. This feature facilitates a design that emphasizes reliability since (once a hermetic seal is opened in orbit), only two moving parts, a grating carrousel and a shutter, are required for regular operation of the HRS. The instrument will be controlled by a computer in the spacecraft. The scientific objectives of the HRS investigation relate to interstellar matter in our own and nearby galaxies, physical processes of stellar mass loss and mass transfer, chemical abundances, bright quasars and Seyfert galaxy nuclei, and solar system phenomena.

  7. High Resolution BPM for Linear Colliders

    NASA Astrophysics Data System (ADS)

    Simon, C.; Chel, S.; Luong, M.; Napoly, O.; Novo, J.; Roudier, D.; Baboi, N.; Noelle, D.; Mildner, N.; Zapfe, K.; Rouvière, N.

    2006-11-01

    A high resolution Beam Position Monitor (BPM) is necessary for the beam-based alignment systems of high energy and low emittance electron linacs. Such a monitor is developed in the framework of the European CARE/SRF programme, in a close collaboration between DESY and CEA/DSM/DAPNIA. This monitor is a radiofrequency re-entrant cavity, which can be used either at room or cryogenic temperature, in an environment where dust particle contamination has to be avoided, such as superconducting cavities in a cryomodule. A first prototype of a re-entrant BPM has already delivered measurements at 2K. inside the first cryomodule (ACC1) on the TESLA Test Facility 2 (TTF2). The performances of this BPM are analyzed both experimentally and theoretically, and the limitations of this existing system clearly identified. A new cavity and new electronics have been designed in order to improve the position resolution down to 1 μm and the damping time down to 10 ns.

  8. High-resolution microwave images of saturn.

    PubMed

    Grossman, A W; Muhleman, D O; Berge, G L

    1989-09-15

    An analysis of high-resolution microwave images of Saturn and Saturn's individual rings is presented. Radio interferometric observations of Saturn taken at the Very Large Array in New Mexico at wavelengths of 2 and 6 centimeters reveal interesting new features in both the atmosphere and rings. The resulting maps show an increase in brightness temperature of about 3 K from equator to pole at both wavelengths, while the 6-centimeter map shows a bright band at northern mid-latitudes. The data are consistent with a radiative transfer model of the atmosphere that constrains the well-mixed, fully saturated, NH(3) mixing ratio to be 1.2 x 10(-4) in a region just below the NH(3) clouds, while the observed bright band indicates a 25 percent relative decrease of NH(3) in northern mid-latitudes. Brightness temperatures for the classical rings are presented. Ring brightness shows a variation with azimuth and is linearly polarized at an average value of about 5 percent. The variations in ring polarization suggest that at least 20 percent of the ring brightness is the result of a single scattering process. PMID:17747882

  9. High-resolution x-ray telescopes

    NASA Astrophysics Data System (ADS)

    O'Dell, Stephen L.; Brissenden, Roger J.; Davis, William N.; Elsner, Ronald F.; Elvis, Martin S.; Freeman, Mark D.; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhail V.; Jerius, Diab; Juda, Michael; Kolodziejczak, Jeffery J.; Murray, Stephen S.; Petre, Robert; Podgorski, William; Ramsey, Brian D.; Reid, Paul B.; Saha, Timo; Schwartz, Daniel A.; Trolier-McKinstry, Susan; Weisskopf, Martin C.; Wilke, Rudeger H. T.; Wolk, Scott; Zhang, William W.

    2010-08-01

    High-energy astrophysics is a relatively young scientific field, made possible by space-borne telescopes. During the half-century history of x-ray astronomy, the sensitivity of focusing x-ray telescopes-through finer angular resolution and increased effective area-has improved by a factor of a 100 million. This technological advance has enabled numerous exciting discoveries and increasingly detailed study of the high-energy universe-including accreting (stellarmass and super-massive) black holes, accreting and isolated neutron stars, pulsar-wind nebulae, shocked plasma in supernova remnants, and hot thermal plasma in clusters of galaxies. As the largest structures in the universe, galaxy clusters constitute a unique laboratory for measuring the gravitational effects of dark matter and of dark energy. Here, we review the history of high-resolution x-ray telescopes and highlight some of the scientific results enabled by these telescopes. Next, we describe the planned next-generation x-ray-astronomy facility-the International X-ray Observatory (IXO). We conclude with an overview of a concept for the next next-generation facility-Generation X. The scientific objectives of such a mission will require very large areas (about 10000 m2) of highly-nested lightweight grazing-incidence mirrors with exceptional (about 0.1-arcsecond) angular resolution. Achieving this angular resolution with lightweight mirrors will likely require on-orbit adjustment of alignment and figure.

  10. Future trends in high-resolution lithography

    NASA Astrophysics Data System (ADS)

    Lawes, R. A.

    2000-02-01

    A perennial question is "what is the future of high-resolution lithography, a key technology that drives the semiconductor industry"? The dominant technology over the last 30 years has been optical lithography, which by lowering wavelengths to 193 nm (ArF) and 157 nm (F 2) and by using optical "tricks" such as phase shift masks, off-axis illumination and phase filters, should be capable of 100 nm CMOS technology. So where does this leave the competition? The 100-nm lithography used to be the domain of electron beam lithography but only in research laboratories. Significant efforts are being made to increase throughput by electron projection (scattering with angular limitation projection electron beam lithography or SCALPEL). X-ray lithography remains a demonstrated R&D tool waiting to be commercially exploited but the initial expenditure to do so is very high. Ion beam lithography and extreme ultraviolet (EUV) ( λ<12 nm) have also received attention in recent years. This paper will concentrate on some of the key issues and speculate on how and when an alternative to optical lithography will be embraced by industry.

  11. High resolution quantum metrology via quantum interpolation

    NASA Astrophysics Data System (ADS)

    Ajoy, Ashok; Liu, Yixiang; Saha, Kasturi; Marseglia, Luca; Jaskula, Jean-Christophe; Cappellaro, Paola

    2016-05-01

    Nitrogen Vacancy (NV) centers in diamond are a promising platform for quantum metrology - in particular for nanoscale magnetic resonance imaging to determine high resolution structures of single molecules placed outside the diamond. The conventional technique for sensing of external nuclear spins involves monitoring the effects of the target nuclear spins on the NV center coherence under dynamical decoupling (the CPMG/XY8 pulse sequence). However, the nuclear spin affects the NV coherence only at precise free evolution times - and finite timing resolution set by hardware often severely limits the sensitivity and resolution of the method. In this work, we overcome this timing resolution barrier by developing a technique to supersample the metrology signal by effectively implementing a quantum interpolation of the spin system dynamics. This method will enable spin sensing at high magnetic fields and high repetition rate, allowing significant improvements in sensitivity and spectral resolution. We experimentally demonstrate a resolution boost by over a factor of 100 for spin sensing and AC magnetometry. The method is shown to be robust, versatile to sensing normal and spurious signal harmonics, and ultimately limited in resolution only by the number of pulses that can be applied.

  12. Holographic high-resolution endoscopic image recording

    NASA Astrophysics Data System (ADS)

    Bjelkhagen, Hans I.

    1991-03-01

    Endoscopic holography or endoholography combines the features of endoscopy and holography. The purpose of endoholographic imaging is to provide the physician with a unique means of extending diagnosis by providing a life-like record of tissue. Endoholographic recording will provide means for microscopic examination of tissue and in some cases may obviate the need to excise specimens for biopsy. In this method holograms which have the unique properties of three-dimensionality large focal depth and high resolution are made with a newly designed endoscope. The endoscope uses a single-mode optical fiber for illumination and single-beam reflection holograms are recorded in close contact with the tissue at the distal end of the endoscope. The holograms are viewed under a microscope. By using the proper combinations of dyes for staining specific tissue types with various wavelengths of laser illumination increased contrast on the cellular level can be obtained. Using dyes such as rose bengal in combination with the 514. 5 nm line of an argon ion laser and trypan blue or methylene blue with the 647. 1 nm line of a krypton ion laser holograms of the stained colon of a dog showed the architecture of the colon''s columnar epithelial cells. It is hoped through chronological study using this method in-vivo an increased understanding of the etiology and pathology of diseases such as Crohn''s diseases colitis proctitis and several different forms of cancer will help

  13. High-resolution imaging using endoscopic holography

    NASA Astrophysics Data System (ADS)

    Bjelkhagen, Hans I.

    1990-08-01

    Endoscopic holography or endoholography combines the features of endoscopy and holography. The purpose of endoholographic imaging is to provide the physician with a unique means of extending diagnosis by providing a life-like record of tissue. Endoholographic recording will provide means for microscopic examination of tissue and in some cases may obviate the need to excise specimens for biopsy. In this method holograms which have the unique properties of three-dimensionality large focal depth and high resolution are made with a newly designed endoscope. The endoscope uses a single-mode optical fiber for illumination and single-beam reflection holograms are recorded in close contact with the tissue at the distal end of the endoscope. The holograms are viewed under a microscope. By using the proper combinations of dyes for staining specific tissue types with various wavelengths of laser illumination increased contrast on the cellular level can be obtained. Using dyes such as rose bengal in combination with the 514. 5 nm line of an argon ion laser and trypan blue or methylene blue with the 647. 1 nm line of a krypton ion laser holograms of the stained colon of a dog showed the architecture of the colon''s columnar epithelial cells. It is hoped through chronological study using this method in-vivo an increased understanding of the etiology and pathology of diseases such as Crohn''s diseases colitis proctitis and several different forms of cancer will help to their control. 1.

  14. High resolution Fourier interferometer-spectrophotopolarimeter

    NASA Technical Reports Server (NTRS)

    Fymat, A. L. (Inventor)

    1976-01-01

    A high-resolution Fourier interferometer-spectrophotopolarimeter is provided using a single linear polarizer-analyzer the transmission axis azimuth of which is positioned successively in the three orientations of 0 deg, 45 deg, and 90 deg, in front of a detector; four flat mirrors, three of which are switchable to either of two positions to direct an incoming beam from an interferometer to the polarizer-analyzer around a sample cell transmitted through a medium in a cell and reflected by medium in the cell; and four fixed focussing lenses, all located in a sample chamber attached at the exit side of the interferometer. This arrangement can provide the distribution of energy and complete polarization state across the spectrum of the reference light entering from the interferometer; the same light after a fixed-angle reflection from the sample cell containing a medium to be analyzed; and the same light after direct transmission through the same sample cell, with the spectral resolution provided by the interferometer.

  15. The High-Resolution Coronal Imager (Hi-C)

    NASA Astrophysics Data System (ADS)

    Kobayashi, Ken; Cirtain, Jonathan; Winebarger, Amy R.; Korreck, Kelly; Golub, Leon; Walsh, Robert W.; De Pontieu, Bart; DeForest, Craig; Title, Alan; Kuzin, Sergey; Savage, Sabrina; Beabout, Dyana; Beabout, Brent; Podgorski, William; Caldwell, David; McCracken, Kenneth; Ordway, Mark; Bergner, Henry; Gates, Richard; McKillop, Sean; Cheimets, Peter; Platt, Simon; Mitchell, Nick; Windt, David

    2014-11-01

    The High-Resolution Coronal Imager (Hi-C) was flown on a NASA sounding rocket on 11 July 2012. The goal of the Hi-C mission was to obtain high-resolution (≈ 0.3 - 0.4''), high-cadence (≈ 5 seconds) images of a solar active region to investigate the dynamics of solar coronal structures at small spatial scales. The instrument consists of a normal-incidence telescope with the optics coated with multilayers to reflect a narrow wavelength range around 19.3 nm (including the Fe xii 19.5-nm spectral line) and a 4096×4096 camera with a plate scale of 0.1'' pixel-1. The target of the Hi-C rocket flight was Active Region 11520. Hi-C obtained 37 full-frame images and 86 partial-frame images during the rocket flight. Analysis of the Hi-C data indicates the corona is structured on scales smaller than currently resolved by existing satellite missions.

  16. Development of Purine-Derived 18F-Labeled Pro-drug Tracers for Imaging of MRP1 Activity with PET

    PubMed Central

    2014-01-01

    Multidrug resistance-associated protein 1 (MRP1) is a drug efflux transporter that has been implicated in the pathology of several neurological diseases and is associated with development of multidrug resistance. To enable measurement of MRP1 function in the living brain, a series of 6-halopurines decorated with fluorinated side chains have been synthesized and evaluated as putative pro-drug tracers. The tracers were designed to undergo conjugation with glutathione within the brain and hence form the corresponding MRP1 substrate tracers in situ. 6-Bromo-7-(2-[18F]fluoroethyl)purine showed good brain uptake and rapid metabolic conversion. Dynamic PET imaging demonstrated a marked difference in brain clearance rates between wild-type and mrp1 knockout mice, suggesting that the tracer can allow noninvasive assessment of MRP1 activity in vivo. PMID:24456310

  17. Potential High Resolution Dosimeters For MRT

    NASA Astrophysics Data System (ADS)

    Bräuer-Krisch, E.; Rosenfeld, A.; Lerch, M.; Petasecca, M.; Akselrod, M.; Sykora, J.; Bartz, J.; Ptaszkiewicz, M.; Olko, P.; Berg, A.; Wieland, M.; Doran, S.; Brochard, T.; Kamlowski, A.; Cellere, G.; Paccagnella, A.; Siegbahn, E. A.; Prezado, Y.; Martinez-Rovira, I.; Bravin, A.; Dusseau, L.; Berkvens, P.

    2010-07-01

    Microbeam Radiation Therapy (MRT) uses highly collimated, quasi-parallel arrays of X-ray microbeams of 50-600 keV, produced by 2nd and 3rd generation synchrotron sources, such as the National Synchrotron Light Source (NSLS) in the U.S., and the European Synchrotron Radiation Facility (ESRF) in France, respectively. High dose rates are necessary to deliver therapeutic doses in microscopic volumes, to avoid spreading of the microbeams by cardiosynchronous movement of the tissues. A small beam divergence and a filtered white beam spectrum in the energy range between 30 and 250 keV results in the advantage of steep dose gradients with a sharper penumbra than that produced in conventional radiotherapy. MRT research over the past 20 years has allowed a vast number of results from preclinical trials on different animal models, including mice, rats, piglets and rabbits. Microbeams in the range between 10 and 100 micron width show an unprecedented sparing of normal radiosensitive tissues as well as preferential damage to malignant tumor tissues. Typically, MRT uses arrays of narrow (˜25-100 micron-wide) microplanar beams separated by wider (100-400 microns centre-to-centre, c-t-c) microplanar spaces. We note that thicker microbeams of 0.1-0.68 mm used by investigators at the NSLS are still called microbeams, although some invesigators in the community prefer to call them minibeams. This report, however, limits it discussion to 25-100 μm microbeams. Peak entrance doses of several hundreds of Gy are surprisingly well tolerated by normal tissues. High resolution dosimetry has been developed over the last two decades, but typical dose ranges are adapted to dose delivery in conventional Radiation Therapy (RT). Spatial resolution in the sub-millimetric range has been achieved, which is currently required for quality assurance measurements in Gamma-knife RT. Most typical commercially available detectors are not suitable for MRT applications at a dose rate of 16000 Gy/s, micron

  18. Large Scale, High Resolution, Mantle Dynamics Modeling

    NASA Astrophysics Data System (ADS)

    Geenen, T.; Berg, A. V.; Spakman, W.

    2007-12-01

    To model the geodynamic evolution of plate convergence, subduction and collision and to allow for a connection to various types of observational data, geophysical, geodetical and geological, we developed a 4D (space-time) numerical mantle convection code. The model is based on a spherical 3D Eulerian fem model, with quadratic elements, on top of which we constructed a 3D Lagrangian particle in cell(PIC) method. We use the PIC method to transport material properties and to incorporate a viscoelastic rheology. Since capturing small scale processes associated with localization phenomena require a high resolution, we spend a considerable effort on implementing solvers suitable to solve for models with over 100 million degrees of freedom. We implemented Additive Schwartz type ILU based methods in combination with a Krylov solver, GMRES. However we found that for problems with over 500 thousend degrees of freedom the convergence of the solver degraded severely. This observation is known from the literature [Saad, 2003] and results from the local character of the ILU preconditioner resulting in a poor approximation of the inverse of A for large A. The size of A for which ILU is no longer usable depends on the condition of A and on the amount of fill in allowed for the ILU preconditioner. We found that for our problems with over 5×105 degrees of freedom convergence became to slow to solve the system within an acceptable amount of walltime, one minute, even when allowing for considerable amount of fill in. We also implemented MUMPS and found good scaling results for problems up to 107 degrees of freedom for up to 32 CPU¡¯s. For problems with over 100 million degrees of freedom we implemented Algebraic Multigrid type methods (AMG) from the ML library [Sala, 2006]. Since multigrid methods are most effective for single parameter problems, we rebuild our model to use the SIMPLE method in the Stokes solver [Patankar, 1980]. We present scaling results from these solvers for 3D

  19. Wavefront metrology for high resolution optical systems

    NASA Astrophysics Data System (ADS)

    Miyakawa, Ryan H.

    Next generation extreme ultraviolet (EUV) optical systems are moving to higher resolution optics to accommodate smaller length scales targeted by the semiconductor industry. As the numerical apertures (NA) of the optics become larger, it becomes increasingly difficult to characterize aberrations due to experimental challenges associated with high-resolution spatial filters and geometrical effects caused by large incident angles of the test wavefront. This dissertation focuses on two methods of wavefront metrology for high resolution optical systems. The first method, lateral shearing interferometry (LSI), is a self-referencing interferometry where the test wavefront is incident on a low spatial frequency grating, and the resulting interference between the diffracted orders is used to reconstruct the wavefront aberrations. LSI has many advantages over other interferometric tests such as phase-shifting point diffraction interferometry (PS/PDI) due to its experimental simplicity, stability, relaxed coherence requirements, and its ability to scale to high numerical apertures. While LSI has historically been a qualitative test, this dissertation presents a novel quantitative investigation of the LSI interferogram. The analysis reveals the existence of systematic aberrations due to the nonlinear angular response from the diffraction grating that compromises the accuracy of LSI at medium to high NAs. In the medium NA regime (0.15 < NA < 0.35), a holographic model is presented that derives the systematic aberrations in closed form, which demonstrates an astigmatism term that scales as the square of the grating defocus. In the high NA regime (0.35 < NA), a geometrical model is introduced that describes the aberrations as a system of transcendental equations that can be solved numerically. The characterization and removal of these systematic errors is a necessary step that unlocks LSI as a viable candidate for high NA EUV optical testing. The second method is a novel image

  20. Potential High Resolution Dosimeters For MRT

    SciTech Connect

    Braeuer-Krisch, E.; Brochard, T.; Prezado, Y.; Bravin, A.; Berkvens, P.; Rosenfeld, A.; Lerch, M.; Petasecca, M.; Akselrod, M.; Sykora, J.; Bartz, J.; Ptaszkiewicz, M.; Olko, P.; Berg, A.; Wieland, M.; Doran, S.; Kamlowski, A.; Cellere, G.

    2010-07-23

    Microbeam Radiation Therapy (MRT) uses highly collimated, quasi-parallel arrays of X-ray microbeams of 50-600 keV, produced by 2nd and 3rd generation synchrotron sources, such as the National Synchrotron Light Source (NSLS) in the U.S., and the European Synchrotron Radiation Facility (ESRF) in France, respectively. High dose rates are necessary to deliver therapeutic doses in microscopic volumes, to avoid spreading of the microbeams by cardiosynchronous movement of the tissues. A small beam divergence and a filtered white beam spectrum in the energy range between 30 and 250 keV results in the advantage of steep dose gradients with a sharper penumbra than that produced in conventional radiotherapy. MRT research over the past 20 years has allowed a vast number of results from preclinical trials on different animal models, including mice, rats, piglets and rabbits. Microbeams in the range between 10 and 100 micron width show an unprecedented sparing of normal radiosensitive tissues as well as preferential damage to malignant tumor tissues. Typically, MRT uses arrays of narrow ({approx}25-100 micron-wide) microplanar beams separated by wider (100-400 microns centre-to-centre, c-t-c) microplanar spaces. We note that thicker microbeams of 0.1-0.68 mm used by investigators at the NSLS are still called microbeams, although some invesigators in the community prefer to call them minibeams. This report, however, limits it discussion to 25-100 {mu}m microbeams. Peak entrance doses of several hundreds of Gy are surprisingly well tolerated by normal tissues. High resolution dosimetry has been developed over the last two decades, but typical dose ranges are adapted to dose delivery in conventional Radiation Therapy (RT). Spatial resolution in the sub-millimetric range has been achieved, which is currently required for quality assurance measurements in Gamma-knife RT. Most typical commercially available detectors are not suitable for MRT applications at a dose rate of 16000 Gy

  1. High-Resolution Radar Imagery of Mars

    NASA Astrophysics Data System (ADS)

    Harmon, John K.; Nolan, M. C.

    2009-09-01

    We present high-resolution radar images of Mars obtained during the 2005 and 2007 oppositions. The images were constructed from long-code delay-Doppler observations made with the Arecibo S-band (13-cm) radar. The average image resolution of 3 km represented a better than order-of-magnitude improvement over pre-upgrade Arecibo imagery of the planet. Images of depolarized reflectivity (an indicator primarily of wavelength-scale surface roughness) show the same bright volcanic flow features seen in earlier imagery, but with much finer detail. A new image of the Elysium region shows fine detail in the radar-bright channels of Athabasca Vallis, Marte Vallis, and Grjota Vallis. The new images of Tharsis and Olympus Mons also show a complex array of radar-bright and radar-dark features. Southern Amazonis exhibits some of the most complex and puzzling radar-bright structure on the planet. Another curiosity is the Chryse/Xanthe/Channels region, where we find some radar-bright features in or adjacent to fluvial chaos structures. Chryse/Xanthe is also the only region of Mars showing radar-bright craters (which are rare on Mars but common on the Moon and Mercury). We also obtained the first delay-Doppler image showing the enhanced backscatter from the residual south polar ice cap. In addition to the depolarized imagery, we were able to make the first delay-Doppler images of the circular polarization ratio (an important diagnostic for surface roughness texture). We find that vast areas of the radar-bright volcanic regions have polarization ratios close to unity. Such high ratios are rare for terrestrial lava flows and only seen for extremely blocky surfaces giving high levels of multiple scattering.

  2. Decadal prediction with a high resolution model

    NASA Astrophysics Data System (ADS)

    Monerie, Paul-Arthur; Valcke, Sophie; Terray, Laurent; Moine, Marie-Pierre

    2016-04-01

    The ability of a high resolution coupled atmosphere-ocean general circulation model (with a horizontal resolution of the quarter degree in the ocean and of about 50 km in the atmosphere) to predict the annual means of temperature, precipitation, sea-ice volume and extent is assessed. Reasonable skill in predicting sea surface temperatures and surface air temperature is obtained, especially over the North Atlantic, the tropical Atlantic and the Indian Ocean. The skill in predicting precipitations is weaker and not significant. The Sea Ice Extent and volume are also reasonably predicted in winter (March) and summer (September). It is however argued that the skill is mainly due to the atmosphere feeding in well-mixed GHGs. The mid-90's subpolar gyre warming is assessed. The model simulates a warming of the North Atlantic Ocean, associated with an increase of the meridional heat transport, a strengthening of the North Atlantic current and a deepening of the mixed layer over the Labrador Sea. The atmosphere plays a role in the warming through a modulation of the North Atlantic Oscillation and a shrinking of the subpolar gyre. At the 3-8 years lead-time, a negative anomaly of pressure, located south of the subpolar gyre is associated with the wind speed decrease over the subpolar gyre. It prevents oceanic heat-loss and favors the northward move, from the subtropical to the subpolar gyre, of anomalously warm and salty water, leading to its warming. We finally argued that the subpolar gyre warming is triggered by the ocean dynamic but the atmosphere can contributes to its sustaining. This work is realised in the framework of the EU FP7 SPECS Project.

  3. The NASA High Resolution Microwave Survey

    NASA Astrophysics Data System (ADS)

    Tarter, J. C.; Gulkis, S.

    1993-05-01

    The NASA High Resolution Microwave Survey (HRMS) began a decade of planned observations to search for signals of extraterrestrial intelligent origin with inaugural ceremonies at two sites on October 12, 1992. At Goldstone, California the Sky Survey began executing precisely controlled scanning patterns on the celestial sphere using a new beam waveguide 34m antenna operating at a frequency near 8500 MHz (X-band). At Arecibo, Puerto Rico the Targeted Search began tracking GL615.1A, one of 24 solar-type stars selected for these inaugural observations, using the NAIC 300m radio telescope operating in a band of frequencies centered at 1406 MHz. Since the initiation of the search, the Sky Survey has completed X-band observations of several dozen sky-frames measuring 30(deg) times 1.5(deg) . In addition, observations of selected areas of the galactic plane have been observed in several frequency bands (1400 MHz and 1600 MHz) using a 26m antenna located near the 34m antenna. The Targeted Search has completed the first 200 hours of observations at Arecibo covering some 300 MHz of bandwidth. This paper summarizes the results of the observations to date, including a synopsis of the interference observed at the Goldstone and Arecibo sites, and a discussion of techniques that will be used to improve future observations. The HRMS program is managed by the Ames Research Center in collaboration with the Jet Propulsion Laboratory. The results presented in this paper represent the efforts of a team of scientists and engineers at these two institutions as well as the SETI Institute, Silicon Engines Inc., John C. Reykjalin Inc., Sverdrup Technology, Sterling Federal Systems, Cornell University, the Harvard-Smithsonian Center for Astrophysics, the American Astronomical Society, Arecibo Observatory, UC Santa Cruz, the University of Washington, UC Berkeley, California Institute of Technology, Georgia Institute of Technology, Innovative Systems, and the Space Telescope Science Institute.

  4. High-resolution phylogenetic microbial community profiling

    SciTech Connect

    Singer, Esther; Coleman-Derr, Devin; Bowman, Brett; Schwientek, Patrick; Clum, Alicia; Copeland, Alex; Ciobanu, Doina; Cheng, Jan-Fang; Gies, Esther; Hallam, Steve; Tringe, Susannah; Woyke, Tanja

    2014-03-17

    The representation of bacterial and archaeal genome sequences is strongly biased towards cultivated organisms, which belong to merely four phylogenetic groups. Functional information and inter-phylum level relationships are still largely underexplored for candidate phyla, which are often referred to as microbial dark matter. Furthermore, a large portion of the 16S rRNA gene records in the GenBank database are labeled as environmental samples and unclassified, which is in part due to low read accuracy, potential chimeric sequences produced during PCR amplifications and the low resolution of short amplicons. In order to improve the phylogenetic classification of novel species and advance our knowledge of the ecosystem function of uncultivated microorganisms, high-throughput full length 16S rRNA gene sequencing methodologies with reduced biases are needed. We evaluated the performance of PacBio single-molecule real-time (SMRT) sequencing in high-resolution phylogenetic microbial community profiling. For this purpose, we compared PacBio and Illumina metagenomic shotgun and 16S rRNA gene sequencing of a mock community as well as of an environmental sample from Sakinaw Lake, British Columbia. Sakinaw Lake is known to contain a large age of microbial species from candidate phyla. Sequencing results show that community structure based on PacBio shotgun and 16S rRNA gene sequences is highly similar in both the mock and the environmental communities. Resolution power and community representation accuracy from SMRT sequencing data appeared to be independent of GC content of microbial genomes and was higher when compared to Illumina-based metagenome shotgun and 16S rRNA gene (iTag) sequences, e.g. full-length sequencing resolved all 23 OTUs in the mock community, while iTags did not resolve closely related species. SMRT sequencing hence offers various potential benefits when characterizing uncharted microbial communities.

  5. Exploring New Challenges of High-Resolution SWOT Satellite Altimetry with a Regional Model of the Solomon Sea

    NASA Astrophysics Data System (ADS)

    Brasseur, P.; Verron, J. A.; Djath, B.; Duran, M.; Gaultier, L.; Gourdeau, L.; Melet, A.; Molines, J. M.; Ubelmann, C.

    2014-12-01

    The upcoming high-resolution SWOT altimetry satellite will provide an unprecedented description of the ocean dynamic topography for studying sub- and meso-scale processes in the ocean. But there is still much uncertainty on the signal that will be observed. There are many scientific questions that are unresolved about the observability of altimetry at vhigh resolution and on the dynamical role of the ocean meso- and submesoscales. In addition, SWOT data will raise specific problems due to the size of the data flows. These issues will probably impact the data assimilation approaches for future scientific or operational oceanography applications. In this work, we propose to use a high-resolution numerical model of the Western Pacific Solomon Sea as a regional laboratory to explore such observability and dynamical issues, as well as new data assimilation challenges raised by SWOT. The Solomon Sea connects subtropical water masses to the equatorial ones through the low latitude western boundary currents and could potentially modulate the tropical Pacific climate. In the South Western Pacific, the Solomon Sea exhibits very intense eddy kinetic energy levels, while relatively little is known about the mesoscale and submesoscale activities in this region. The complex bathymetry of the region, complicated by the presence of narrow straits and numerous islands, raises specific challenges. So far, a Solomon sea model configuration has been set up at 1/36° resolution. Numerical simulations have been performed to explore the meso- and submesoscales dynamics. The numerical solutions which have been validated against available in situ data, show the development of small scale features, eddies, fronts and filaments. Spectral analysis reveals a behavior that is consistent with the SQG theory. There is a clear evidence of energy cascade from the small scales including the submesoscales, although those submesoscales are only partially resolved by the model. In parallel

  6. Tracer Technique

    NASA Astrophysics Data System (ADS)

    Haba, H.; Motomura, S.; Kamino, S.; Enomoto, S.

    In radioactive tracer technique, radioactive nuclides are used to follow the behavior of elements or chemical species in chemical and other processes. This is realized by means of radioactivity measurement. In 1913, Hevesy and Paneth succeeded in determining the extremely low solubility of lead salts by using naturally occurring 210Pb as a radioactive tracer. As various radioactive nuclides became artificially available, this technique has been widely employed in studies of chemical equilibrium and reactions as well as in chemical analysis. It is also an essential technique in biochemical, biological, medical, geological, and environmental studies. Medical diagnosis and industrial process control are the fields of its most important practical application. In this chapter, fundamental ideas concerning radioactive tracers will be described followed by their application with typical examples. Detailed description on their application to life sciences and medicine is given in Vol. 4.

  7. A High-Resolution, Three-Dimensional Model of Jupiter's Great Red Spot

    NASA Technical Reports Server (NTRS)

    Cho, James Y.-K.; delaTorreJuarez, Manuel; Ingersoll, Andrew P.; Dritschel, David G.

    2001-01-01

    The turbulent flow at the periphery of the Great Red Spot (GRS) contains many fine-scale filamentary structures, while the more quiescent core, bounded by a narrow high- velocity ring, exhibits organized, possibly counterrotating, motion. Past studies have neither been able to capture this complexity nor adequately study the effect of vertical stratification L(sub R)(zeta) on the GRS. We present results from a series of high-resolution, three-dimensional simulations that advect the dynamical tracer, potential vorticity. The detailed flow is successfully captured with a characteristic value of L(sub R) approx. equals 2000 km, independent of the precise vertical stratification profile.

  8. High-resolution three-dimensional imaging radar

    NASA Technical Reports Server (NTRS)

    Cooper, Ken B. (Inventor); Chattopadhyay, Goutam (Inventor); Siegel, Peter H. (Inventor); Dengler, Robert J. (Inventor); Schlecht, Erich T. (Inventor); Mehdi, Imran (Inventor); Skalare, Anders J. (Inventor)

    2010-01-01

    A three-dimensional imaging radar operating at high frequency e.g., 670 GHz, is disclosed. The active target illumination inherent in radar solves the problem of low signal power and narrow-band detection by using submillimeter heterodyne mixer receivers. A submillimeter imaging radar may use low phase-noise synthesizers and a fast chirper to generate a frequency-modulated continuous-wave (FMCW) waveform. Three-dimensional images are generated through range information derived for each pixel scanned over a target. A peak finding algorithm may be used in processing for each pixel to differentiate material layers of the target. Improved focusing is achieved through a compensation signal sampled from a point source calibration target and applied to received signals from active targets prior to FFT-based range compression to extract and display high-resolution target images. Such an imaging radar has particular application in detecting concealed weapons or contraband.

  9. High resolution surface wave dispersion studies in China

    SciTech Connect

    Jones, L.E.; Patton, H.J.

    1997-11-01

    The Los Alamos National Laboratory regional calibration project is actively assembling a database of surface-wave dispersion information for China and surrounding areas. As part of the effort to characterize surface wave dispersion in China, we integrate prior long period results from the University of Colorado with our shorter period dispersion measurements in a high resolution survey of key monitoring areas. Focusing on western China initially, we employ broadband data recorded on CDSN stations, and regional events (m{sub b} 4 and above). Our approach is twofold, employing path specific calibration of key stations and well-recorded reference events, and tomographic inference to provide group velocity curves for regions with sparse station distribution and little seismic activity. Initial dispersion studies at Chinese stations WMQ and LZH show substantial azimuthal variation in dispersion, reinforcing the need for careful determination of source regions for path-specific calibration.

  10. III-Nitride full-scale high-resolution microdisplays

    NASA Astrophysics Data System (ADS)

    Day, Jacob; Li, J.; Lie, D. Y. C.; Bradford, Charles; Lin, J. Y.; Jiang, H. X.

    2011-07-01

    We report the realization and properties of a high-resolution solid-state self-emissive microdisplay based on III-nitride semiconductor micro-size light emitting diodes (µLEDs) capable of delivering video graphics images. The luminance level of III-nitride microdisplays is several orders of magnitude higher than those of liquid crystal and organic-LED displays. The pixel emission intensity was almost constant over an operational temperature range from 100 to -100 °C. The outstanding performance is a direct attribute of III-nitride semiconductors. An energy efficient active drive scheme is accomplished by hybrid integration between µLED arrays and Si CMOS (complementary metal-oxide-semiconductor) active matrix integrated circuits. These integrated devices could play important roles in emerging fields such as biophotonics and optogenetics, as well as ultra-portable products such as next generation pico-projectors.

  11. High Resolution Velocity Structure in Eastern Turkey

    NASA Astrophysics Data System (ADS)

    Pasyanos, M. E.; Gok, R.; Zor, E.; Walter, W. R.

    2004-12-01

    We investigate the crust and upper mantle structure of eastern Turkey where the Anatolian, Arabian and Eurasian Plates meet, forming a complex tectonic regime. The Bitlis suture is a continental collision zone between the Anatolian plateau and the Arabian plate. Broadband data available through the Eastern Turkey Seismic Experiment (ETSE) provide a unique opportunity for studying the high resolution velocity structure of the region. Zor et al. (2003) found an average 46 km thick crust in the Anatolian plateau using a six-layered grid search inversion of the ETSE receiver functions. Receiver functions are sensitive to the velocity contrast of interfaces and the relative travel time of converted and reverberated waves between those interfaces. The interpretation of receiver functions alone, however, may result in an apparent depth-velocity trade-off [Ammon et al., 1990]. In order to improve upon this velocity model, we have combined the receiver functions with surface wave data using the joint inversion method of Julia et al. (2000). In this technique, the two sets of observations are combined into a single algebraic equation and each data set is weighted by an estimate of the uncertainty in the observations. The receiver functions are calculated using an iterative time-domain deconvolution technique. We also consider azimuthal changes in the receiver functions and have stacked them into different groups accordingly. We are improving our surface wave model by making Love and Rayleigh dispersion measurements at the ETSE stations and incorporating them into a regional group velocity model for periods between 10 and 100 seconds. Preliminary results indicate a strong trend in the long period group velocities toward the northeast, indicating slow upper mantle velocities in the area consistent with Pn, Sn and receiver function results. Starting models used for the joint inversions include both a 1-D model from a 12-ton dam shot recorded by ETSE [Gurbuz et al., 2004] and

  12. High Resolution Velocity Structure in Eastern Turkey

    SciTech Connect

    Pasyanos, M; Gok, R; Zor, E; Walter, W

    2004-09-03

    We investigate the crustal and upper mantle structure of eastern Turkey where the Anatolian, Arabian and Eurasian Plates meet and form a complex tectonic structure. The Bitlis suture is a continental collision zone between the Anatolian plateau and the Arabian plate. Broadband data available through the Eastern Turkey Seismic Experiment (ETSE) provided a unique opportunity for studying the high resolution velocity structure. Zor et al. found an average 46 km thick crust in Anatolian plateau using six-layered grid search inversion of the ETSE receiver functions. Receiver functions are sensitive to the velocity contrast of interfaces and the relative travel time of converted and reverberated waves between those interfaces. The interpretation of receiver function alone with many-layered parameterization may result in an apparent depth-velocity tradeoff. In order to improve previous velocity model, we employed the joint inversion method with many layered parameterization of Julia et al. (2000) to the ETSE receiver functions. In this technique, the receiver function and surface-wave observations are combined into a single algebraic equation and each data set is weighted by an estimate of the uncertainty in the observations. We consider azimuthal changes of receiver functions and have stacked them into different groups. We calculated the receiver functions using iterative time-domain deconvolution technique and surface wave group velocity dispersion curves between 10-100 sec. We are making surface wave dispersion measurements at the ETSE stations and have incorporated them into a regional group velocity model. Preliminary results indicate a strong trend in the long period group velocity in the northeast. This indicates slow upper mantle velocities in the region consistent with Pn, Sn and receiver function results. We started with both the 1-D model that is obtained with the 12 tones dam explosion shot data recorded by ETSE network and the existing receiver function

  13. High Resolution Airborne Shallow Water Mapping

    NASA Astrophysics Data System (ADS)

    Steinbacher, F.; Pfennigbauer, M.; Aufleger, M.; Ullrich, A.

    2012-07-01

    In order to meet the requirements of the European Water Framework Directive (EU-WFD), authorities face the problem of repeatedly performing area-wide surveying of all kinds of inland waters. Especially for mid-sized or small rivers this is a considerable challenge imposing insurmountable logistical efforts and costs. It is therefore investigated if large-scale surveying of a river system on an operational basis is feasible by employing airborne hydrographic laser scanning. In cooperation with the Bavarian Water Authority (WWA Weilheim) a pilot project was initiated by the Unit of Hydraulic Engineering at the University of Innsbruck and RIEGL Laser Measurement Systems exploiting the possibilities of a new LIDAR measurement system with high spatial resolution and high measurement rate to capture about 70 km of riverbed and foreland for the river Loisach in Bavaria/Germany and the estuary and parts of the shoreline (about 40km in length) of lake Ammersee. The entire area surveyed was referenced to classic terrestrial cross-section surveys with the aim to derive products for the monitoring and managing needs of the inland water bodies forced by the EU-WFD. The survey was performed in July 2011 by helicopter and airplane and took 3 days in total. In addition, high resolution areal images were taken to provide an optical reference, offering a wide range of possibilities on further research, monitoring, and managing responsibilities. The operating altitude was about 500 m to maintain eye-safety, even for the aided eye, the airspeed was about 55 kts for the helicopter and 75 kts for the aircraft. The helicopter was used in the alpine regions while the fixed wing aircraft was used in the plains and the urban area, using appropriate scan rates to receive evenly distributed point clouds. The resulting point density ranged from 10 to 25 points per square meter. By carefully selecting days with optimum water quality, satisfactory penetration down to the river bed was achieved

  14. The HFIP High Resolution Hurricane Forecast Test

    NASA Astrophysics Data System (ADS)

    Nance, L. B.; Bernardet, L.; Bao, S.; Brown, B.; Carson, L.; Fowler, T.; Halley Gotway, J.; Harrop, C.; Szoke, E.; Tollerud, E. I.; Wolff, J.; Yuan, H.

    2010-12-01

    Tropical cyclones are a serious concern for the nation, causing significant risk to life, property and economic vitality. The National Oceanic and Atmospheric Administration (NOAA) National Weather Service has a mission of issuing tropical cyclone forecasts and warnings, aimed at protecting life and property and enhancing the national economy. In the last 10 years, the errors in hurricane track forecasts have been reduced by about 50% through improved model guidance, enhanced observations, and forecaster expertise. However, little progress has been made during this period toward reducing forecasted intensity errors. To address this shortcoming, NOAA established the Hurricane Forecast Improvement Project (HFIP) in 2007. HFIP is a 10-year plan to improve one to five day tropical cyclone forecasts, with a focus on rapid intensity change. Recent research suggests that prediction models with grid spacing less than 1 km in the inner core of the hurricane may provide a substantial improvement in intensity forecasts. The 2008-09 staging of the High Resolution Hurricane (HRH) Test focused on quantifying the impact of increased horizontal resolution in numerical models on hurricane intensity forecasts. The primary goal of this test was an evaluation of the effect of increasing horizontal resolution within a given model across a variety of storms with different intensity, location and structure. The test focused on 69 retrospectives cases from the 2005 and 2007 hurricane seasons. Six modeling groups participated in the HRH test utilizing a variety of models, including three configurations of the Weather Research and Forecasting (WRF) model, the operational GFDL model, the Navy’s tropical cyclone model, and a model developed at the University of Wisconsin-Madison (UWM). The Development Testbed Center (DTC) was tasked with providing objective verification statistics for a variety of metrics. This presentation provides an overview of the HRH Test and a summary of the standard

  15. U Activity Ratios in Surface Waters as Tracers and Chronometers of Water Transfers in the Critical zone;

    NASA Astrophysics Data System (ADS)

    Chabaux, F.

    2015-12-01

    The use of radioactive disequilibria as tracers and chronometers of weathering processes and related mass transfers has been recognized since the 60'. The development, over the last two decades, of analytical methods for measuring very precisely U-series nuclides (especially, 234U, 230Th and 226Ra) in environmental samples has opened up new scientific applications in Earth Surface Sciences. Here, we propose to present the potential of U activity ratios in surface waters as geochemical tracer and chronometer of water transfers at a watershed scale. This will be illustrated from studies performed at different scales, with the analysis of U activity ratios in surface waters from small watersheds (Strengbach and Ringelbach watersheds in the Vosges Mountain, France) but also from watersheds of much more regional extension (e.g., the Upper Rhine basin or the Ganges basin). These various studies show that variations of U activity ratios in surface waters are mainly associated with 234U-238U fractionations occurring during the water transfer within the bedrock, which intensity depends on two main parameters: the petro-physical characteristics of the aquifer, principally the geometry of water-rock interfaces and the duration of the water-rock interactions. This readily explains why different U activity ratios (UAR) can be observed in the different aquifers of a continental hydrosystem and hence why UAR can be used to trace the source of river waters. For a hydrological system developed on a substratum marked by fairly homogeneous petro-physical characteristics, the main parameter controlling the UAR in waters draining such a system would be the duration of the water-rock interactions. Variations of UAR in stream or spring waters of such a system can therefore be modeled using simple reactive transport model, which allows the estimation of both the dissolution rate of the bedrock and the residence time of the waters within the aquifer.

  16. A high resolution solar atlas for fluorescence calculations

    NASA Technical Reports Server (NTRS)

    Hearn, M. F.; Ohlmacher, J. T.; Schleicher, D. G.

    1983-01-01

    The characteristics required of a solar atlas to be used for studying the fluorescence process in comets are examined. Several sources of low resolution data were combined to provide an absolutely calibrated spectrum from 2250 A to 7000A. Three different sources of high resolution data were also used to cover this same spectral range. The low resolution data were then used to put each high resolution spectrum on an absolute scale. The three high resolution spectra were then combined in their overlap regions to produce a single, absolutely calibrated high resolution spectrum over the entire spectral range.

  17. High Resolution Simulation in the Eastern Amazonia

    NASA Astrophysics Data System (ADS)

    Cohen, J.; Sa, L.; Nogueira, D.; Gandu, A.

    2006-05-01

    produced by the BRAMS model shows that the numerical simulation reproduced both LLJs of November 13 and 14 at, 06 UTC. However, their magnitude was about 2 and 3 m/s lower and their height was higher than what was observed. In order to verify the origin of the LLJ, the variability of the wind at the jet level, during the numerical simulation in grid 1, was analyzed. In the afternoon, it was observed the increase in wind speed at the Atlantic Coast associated to sea breeze circulation. Nonetheless, at 00 UTC, this maximum speed center penetrated the continent and reached the region of Caxiuanã. Indeed, this circulation was under a canalization effect due to the rivers distribution. On November 13, the sea breeze formed again. However, the circulation on this day was relatively weak. The numerical simulations with this high resolution model indicated the occurrence of low level jets. Nevertheless, it did not reproduce in detail some of the observed characteristics of the flow. An important aspect revealed by the simulations with BRAMS was the origin of the jets, which is associated to a phenomenon of canalization of the flow above zones where there are some of the great rivers in the Northeast of Para.

  18. Ellerman bombs: Advances driven by high-resolution observations

    NASA Astrophysics Data System (ADS)

    Vissers, Gregal

    Ellerman bombs, transient brightenings that have traditionally been observed in the wings of the Balmer Halpha line, are a ubiquitous phenomenon in the lower atmosphere of active regions with considerable flux emergence. These explosive events display sub-arcsecond fine structure, fast dynamical evolution and their energies tend to fall in the nanoflare ballpark. Over the past decade and a half, several high-resolution ground-based and space-based telescopes have contributed greatly to further characterising Ellerman bombs, offering a view in spectral diagnostics ranging from the UV to the infrared. I will highlight some of the recent advances that have been made - both observationally and from a theoretical point of view - in determining their properties (quantitative morphology, energies, flows and proper motion, driving mechanism, etc.), and discuss the potential of observations from relatively new space-based telescopes, such as SDO and IRIS, to add to our understanding of this phenomenon.

  19. Porous silicon phantoms for high-resolution scintillation imaging

    NASA Astrophysics Data System (ADS)

    Di Francia, G.; Scafè, R.; De Vincentis, G.; La Ferrara, V.; Iurlaro, G.; Nasti, I.; Montani, L.; Pellegrini, R.; Betti, M.; Martucciello, N.; Pani, R.

    2006-12-01

    High resolution radionuclide imaging requires phantoms with precise geometries and known activities using either Anger cameras equipped with pinhole collimators or dedicated small animal devices. Porous silicon samples, having areas of different shape and size, can be made and loaded with a radioactive material, obtaining: (a) precise radio-emitting figures corresponding to the porous areas geometry, (b) a radioactivity of each figure depending on the pore's specifications, and (c) the same emission energy to be used in true exams. To this aim a sample with porous circular areas has been made and loaded with a 99mTcO 4- solution. Imaging has been obtained using both general purpose and pinhole collimators. This first sample shows some defects that are analyzed and discussed.

  20. Thermal design concept for a high resolution UV spectrometer

    NASA Technical Reports Server (NTRS)

    Caruso, P.; Stipandic, E.

    1979-01-01

    The thermal design concept described has been developed for the High Resolution UV Spectrometer/Polarimeter to be flown on the Solar Maximum Mission. Based on experience gained from a similar Orbiting Solar Observatory mission payload, it has been recognized that initial protection of the optical elements, contamination control, reduction of scattered light, tight bulk temperature, and gradient constraints are key elements that must be accommodated in any thermal control concept for this class of instrument. Salient features of the design include: (1) a telescope door providing contamination protection of an aplanatic Gregorian telescope; (2) a rastering system for the secondary mirror; (3) a unique solar heat absorbing device; (4) heat pipes and special radiators; (5) heaters for active temperature control and optics contamination protection; and (6) high precision platinum resistance thermometers. Viability of the design concept has been established by extensive thermal analysis and some subsystem testing. A summary of analytical and test results is included.

  1. High resolution EEG hyperscanning during a card game.

    PubMed

    Babiloni, F; Cincotti, F; Mattia, D; De Vico Fallani, F; Tocci, A; Bianchi, L; Salinari, S; Marciani, Mg; Colosimo, A; Astolfi, L

    2007-01-01

    In order to study the concurrent activity in subjects interacting in cooperation or competition activities, the issue of the simultaneous recording of their brain activity became mandatory. The simultaneous recording of neuroelectric activity of the brain is called "EEG hyperscanning". We would like present results obtained by EEG hyperscannings performed on a group of subjects engaged in a card game. The EEG hyperscannings have been performed with the simultaneous use of high resolution EEG devices on groups of four subjects while they were playing a card game. We estimated the concurrent activity in multiple brains of the group and we depicted the causal connections between regions of different brains. Results obtained in a study of several groups recorded by the EEG hyperscanning reveal larger activity in prefrontal and anterior cingulated cortex in different frequency bands for the player that start the game when compared to other players. EEG hyperscannings will open a different area for the study of neuroscience, in which the activity of multiple brains during social cooperation could be investigated. PMID:18003119

  2. Surface-based partial-volume correction for high-resolution PET.

    PubMed

    Funck, Thomas; Paquette, Caroline; Evans, Alan; Thiel, Alexander

    2014-11-15

    Tissue radioactivity concentrations, measured with positron emission tomography (PET) are subject to partial volume effects (PVE) due to the limited spatial resolution of the scanner. Last generation high-resolution PET cameras with a full width at half maximum (FWHM) of 2-4mm are less prone to PVEs than previous generations. Corrections for PVEs are still necessary, especially when studying small brain stem nuclei or small variations in cortical neuroreceptor concentrations which may be related to cytoarchitectonic differences. Although several partial-volume correction (PVC) algorithms exist, these are frequently based on a priori assumptions about tracer distribution or only yield corrected values of regional activity concentrations without providing PVE corrected images. We developed a new iterative deconvolution algorithm (idSURF) for PVC of PET images that aims to overcome these limitations by using two innovative techniques: 1) the incorporation of anatomic information from a cortical gray matter surface representation, extracted from magnetic resonance imaging (MRI) and 2) the use of anatomically constrained filtering to attenuate noise. PVE corrected images were generated with idSURF implemented into a non-interactive processing pipeline. idSURF was validated using simulated and clinical PET data sets and compared to a frequently used standard PVC method (Geometric Transfer Matrix: GTM). The results on simulated data sets show that idSURF consistently recovers accurate radiotracer concentrations within 1-5% of true values. Both radiotracer concentrations and non-displaceable binding potential (BPnd) values derived from clinical PET data sets with idSURF were highly correlated with those obtained with the standard PVC method (R(2) = 0.99, error = 0%-3.2%). These results suggest that idSURF is a valid and potentially clinically useful PVC method for automatic processing of large numbers of PET data sets. PMID:25175542

  3. High resolution infrared acquisitions droning over the LUSI mud eruption.

    NASA Astrophysics Data System (ADS)

    Di Felice, Fabio; Romeo, Giovanni; Di Stefano, Giuseppe; Mazzini, Adriano

    2016-04-01

    The use of low-cost hand-held infrared (IR) thermal cameras based on uncooled micro-bolometer detector arrays became more widespread during the recent years. Thermal cameras have the ability to estimate temperature values without contact and therefore can be used in circumstances where objects are difficult or dangerous to reach such as volcanic eruptions. Since May 2006 the Indonesian LUSI mud eruption continues to spew boiling mud, water, aqueous vapor, CO2, CH4 and covers a surface of nearly 7 km2. At this locality we performed surveys over the unreachable erupting crater. In the framework of the LUSI Lab project (ERC grant n° 308126), in 2014 and 2015, we acquired high resolution infrared images using a specifically equipped remote-controlled drone flying at an altitude of m 100. The drone is equipped with GPS and an autopilot system that allows pre-programming the flying path or designing grids. The mounted thermal camera has peak spectral sensitivity in LW wavelength (μm 10) that is characterized by low water vapor and CO2 absorption. The low distance (high resolution) acquisitions have a temperature detail every cm 40, therefore it is possible to detect and observe physical phenomena such as thermodynamic behavior, hot mud and fluids emissions locations and their time shifts. Despite the harsh logistics and the continuously varying gas concentrations we managed to collect thermal images to estimate the crater zone spatial thermal variations. We applied atmosphere corrections to calculate infrared absorption by high concentration of water vapor. Thousands of images have been stitched together to obtain a mosaic of the crater zone. Regular monitoring with heat variation measurements collected, e.g. every six months, could give important information about the volcano activity estimating its evolution. A future data base of infrared high resolution and visible images stored in a web server could be a useful monitoring tool. An interesting development will be

  4. Using Formaldehyde to Create High Resolution Temperature Maps of CMZ Clouds

    NASA Astrophysics Data System (ADS)

    Castaño, Jimmy

    2016-01-01

    80% of the dense molecular gas in our Galaxy resides in the central few hundred parsecs, known as the Central Molecular Zone (CMZ). From our understanding of star formation, we would expect a comparatively high star formation rate in this region, but the estimates so far indicate that only 5-10% of the star formation in our Galaxy occurs there. There are a number of physical effects that may be causing this, but we particularly wish to investigate the role of the temperature of the gas - which initial estimates put at an average of 50-100 K or about a factor of 5 higher than elsewhere in the disk. Armed with the data taken by the SMA Legacy Survey of the CMZ, we aim to compare parameters two transition lines for the dense gas tracer H2CO which are particularly sensitive to temperature to measure the gas temperature on 0.2 pc scales. Ultimately we provide a high resolution temperature map for a set of clouds in the CMZ dubbed "the three little pigs" to provide an initial comparison with similar work done with ammonia tracers in order to pave the way for a high resolution temperature map of the entire CMZ.

  5. High resolution bragg focusing optics for synchrotron monochromators and analyzers

    SciTech Connect

    Knapp, G.S.; Beno, M.A.; Gofron, K.J.

    1997-07-01

    A number of different applications for high resolution Bragg Focusing Optics are reviewed. Applications include Sagittal Focusing, Energy Dispersive optics for x-ray absorption and diffraction, a curved analyzer-multichannel detector method for efficient acquisition of powder and small angle scattering data, the use of Backscattering Analyzers for very high resolution inelastic scattering, and curved crystals for high energy applications.

  6. Chandra High Resolution Camera (HRC). Rev. 59

    NASA Technical Reports Server (NTRS)

    Murray, Stephen

    2004-01-01

    This monthly report discusses management and general status, mission support and operations, and science activities. A technical memorandum entitled "Failure Analysis of HRC Flight Relay" is included with the report.

  7. Advancing Cyberinfrastructure to support high resolution water resources modeling

    NASA Astrophysics Data System (ADS)

    Tarboton, D. G.; Ogden, F. L.; Jones, N.; Horsburgh, J. S.

    2012-12-01

    Addressing the problem of how the availability and quality of water resources at large scales are sensitive to climate variability, watershed alterations and management activities requires computational resources that combine data from multiple sources and support integrated modeling. Related cyberinfrastructure challenges include: 1) how can we best structure data and computer models to address this scientific problem through the use of high-performance and data-intensive computing, and 2) how can we do this in a way that discipline scientists without extensive computational and algorithmic knowledge and experience can take advantage of advances in cyberinfrastructure? This presentation will describe a new system called CI-WATER that is being developed to address these challenges and advance high resolution water resources modeling in the Western U.S. We are building on existing tools that enable collaboration to develop model and data interfaces that link integrated system models running within an HPC environment to multiple data sources. Our goal is to enhance the use of computational simulation and data-intensive modeling to better understand water resources. Addressing water resource problems in the Western U.S. requires simulation of natural and engineered systems, as well as representation of legal (water rights) and institutional constraints alongside the representation of physical processes. We are establishing data services to represent the engineered infrastructure and legal and institutional systems in a way that they can be used with high resolution multi-physics watershed modeling at high spatial resolution. These services will enable incorporation of location-specific information on water management infrastructure and systems into the assessment of regional water availability in the face of growing demands, uncertain future meteorological forcings, and existing prior-appropriations water rights. This presentation will discuss the informatics

  8. Theme issue "High Resolution Earth Imaging for Geospatial Information"

    NASA Astrophysics Data System (ADS)

    Heipke, Christian; Soergel, Uwe; Rottensteiner, Franz; Jutzi, Boris

    2015-02-01

    Earth imaging from air and space has undergone major changes over the last decade. Examples of new and significant developments comprise the development and constant improvement of digital aerial cameras, multiple-echo and full-waveform laser scanners and the appearance of geosensor networks and unconventional platforms, most notably unmanned aircraft systems (UAS), sometimes called unmanned aerial vehicles (UAV) or remotely piloted aircraft systems (RPAS), and the ever increasing number of high-resolution and hyperspectral optical and SAR satellite sensors, small satellites and satellite constellations, which allow for both, a continued availability of satellite data over long periods of time, and a very short revisit time for any location on the globe. To give few examples: the latest Landsat satellite, appropriately called the Landsat data continuity mission or LDCM was launched on February 2013, continuing the Landsat mission which began back in 1972; during 2013 and 2014 France has put the SPOT 6 and 7 twin satellites into orbit, extending the history of high resolution space images, which started in 1986; and in April 2014 the European Space Agency (ESA) successfully launched the Sentinel 1A satellite with a synthetic aperture radar (SAR) sensor, the first of a fleet of different sensors that will be sent into space in the coming years. Sentinel 1A together with its twin system Sentinel 1B, to be launched in 2016, will continue the tremendous success story of ESA's C band SAR satellite activities dating back to 1991. Like the predecessors ERS 1, ERS 2, and Envisat ASAR, the Sentinel 1 systems are designed to cover the entire land mass with medium resolution, the repeat cycle is 12 days for Sentinel 1A alone and will even drop to six days as soon as both satellites are operational.

  9. In Situ Tracer method for establishing the presence and predicting the activity of heavy metal-reducing microbes in the subsurface. Final Report

    SciTech Connect

    Hatfield, K.

    2003-07-01

    Tracer method to establish presence and distribution of chromium reducing microbes. The primary objective of this research was to establish an in situ tracer method for detecting the presence. distribution. and activity of subsurface heavy metal-reducing microorganisms. Research focused on microbial systems responsible for the reduction of chromium and a suite of biotracers coupled to the reduction process. The tracer method developed may be used to characterize sites contaminated with chromium or expedite bioremediation: and although research focused on chromium. the method can be easily extended to other metals, organics, and radionuclides. This brief final report contains three major sections. The first identifies specific products of the research effort such as students supported and publications. The second section briefly presents major research findings, while the last section summarizes the overall research effort.

  10. High resolution imaging of galaxy cores

    NASA Technical Reports Server (NTRS)

    Crane, P.; Stiavelli, M.; King, I. R.; Deharveng, J. M.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.; Disney, M. J.; Jakobsen, P.

    1993-01-01

    Surface photometry data obtained with the Faint Object Camera of the Hubble Space Telescope in the cores of ten galaxies is presented. The major results are: (1) none of the galaxies show truly 'isothermal' cores, (2) galaxies with nuclear activity show very similar light profiles, (3) all objects show central mass densities above 10 exp 3 solar masses/cu pc3, and (4) four of the galaxies (M87, NGC 3862, NGC 4594, NGC 6251) show evidence for exceptional nuclear mass concentrations.

  11. High resolution airborne geophysics at hazardous waste disposal sites

    SciTech Connect

    Beard, L.P.; Nyquist, J.E.; Doll, W.E.; Chong Foo, M.; Gamey, T.J.

    1995-06-01

    In 1994, a high resolution helicopter geophysical survey was conducted over portions of the Oak Ridge Reservation, Tennessee. The 1800 line kilometer survey included multi-frequency electromagnetic and magnetic sensors. The areas covered by the high resolution portion of the survey were selected on the basis of their importance to the environmental restoration effort and on data obtained from the reconnaissance phase of the airborne survey in which electromagnetic, magnetic, and radiometric data were collected over the entire Oak Ridge Reservation in 1992--1993. The high resolution phase had lower sensor heights, more and higher EM frequencies, and tighter line spacings than did the reconnaissance survey. When flying over exceptionally clear areas, the high resolution bird came within a few meters of the ground surface. Unfortunately, even sparse trees and power or phone lines could prevent the bird from being towed safely at low altitude, and over such areas it was more usual for it to be flown at about the same altitude as the bird in the reconnaissance survey, about 30m. Even so, the magnetometers used in the high resolution phase were 20m closer to the ground than in the reconnaissance phase because they were mounted on the tail of the bird rather than on the tow cable above the bird. The EM frequencies used in the high resolution survey ranged from 7400Hz to 67000Hz. Only the horizontal coplanar loop configuration was used in the high resolution flyovers.

  12. High resolution spectroscopy to support atmospheric measurements

    NASA Technical Reports Server (NTRS)

    Smith, Mary Ann H.; Devi, V. Malathy; Rinsland, Curtis P.; Benner, D. Chris; Harvey, Gale A.

    1990-01-01

    Detailed knowledge of the molecular spectra of ozone and other infrared-active atmospheric species is needed for accurate calculation of atmospheric heating and cooling rates in climate models. Remote sensing experiments on the Nimbus-7 satellites and the Spacelab-3 Space Shuttle Mission have shown that space-based measurements of infrared absorption or emission can be used to accurately determine the concentrations and distributions of stratospheric species on a global scale. The objective of this research task is to improve knowledge of the spectroscopic line parameters (positions, intensities, assignments, halfwidths, and pressure-induced shifts) of key atmospheric constituents through laboratory measurements.

  13. Road Extraction from High Resolution Satellite Images

    NASA Astrophysics Data System (ADS)

    Özkaya, M.

    2012-07-01

    Roads are significant objects of an infrastructure and the extraction of roads from aerial and satellite images are important for different applications such as automated map generation and change detection. Roads are also important to detect other structures such as buildings and urban areas. In this paper, the road extraction approach is based on Active Contour Models for 1-meter resolution gray level images. Active Contour Models contains Snake Approach. During applications, the road structure was separated as salient-roads, non-salient roads and crossings and extraction of these is provided by using Ribbon Snake and Ziplock Snake methods. These methods are derived from traditional snake model. Finally, various experimental results were presented. Ribbon and Ziplock Snake methods were compared for both salient and non-salient roads. Also these methods were used to extract roads in an image. While Ribbon snake is described for extraction of salient roads in an image, Ziplock snake is applied for extraction of non-salient roads. Beside these, some constant variables in literature were redefined and expressed in a formula as depending on snake approach and a new approach for extraction of crossroads were described and tried.

  14. Invariant high resolution optical skin imaging

    NASA Astrophysics Data System (ADS)

    Murali, Supraja; Rolland, Jannick

    2007-02-01

    Optical Coherence Microscopy (OCM) is a bio-medical low coherence interferometric imaging technique that has become a topic of active research because of its ability to provide accurate, non-invasive cross-sectional images of biological tissue with much greater resolution than the current common technique ultrasound. OCM is a derivative of Optical Coherence Tomography (OCT) that enables greater resolution imposed by the implementation of an optical confocal design involving high numerical aperture (NA) focusing in the sample. The primary setback of OCM, however is the depth dependence of the lateral resolution obtained that arises from the smaller depth of focus of the high NA beam. We propose to overcome this limitation using a dynamic focusing lens design that can achieve quasi-invariant lateral resolution up to 1.5mm depth of skin tissue.

  15. Development of High-Resolution Scintillator Systems

    SciTech Connect

    Larry A. Franks; Warnick J. Kernan

    2007-09-01

    Mercuric iodide (HgI2) is a well known material for the direct detection of gamma-rays; however, the largest volume achievable is limited by the thickness of the detector which needs to be a small fraction of the average trapping length for electrons. We report results of using HgI2 crystals to fabricate photocells used in the readout of scintillators. The optical spectral response and efficiency of these photocells were measured and will be reported. Nuclear response from an HgI2 photocell that was optically matched to a cerium-activated scintillator is presented and discussed. Further improvements can be expected by optimizing the transparent contact technology.

  16. Robust Tips for High Resolution Chemical Imaging

    NASA Astrophysics Data System (ADS)

    Barrios, Carlos; Malkovskiy, Andrey; Kisliuk, Alexander; Sokolov, Alexei; Foster, Mark

    2009-03-01

    Tip enhanced Raman spectroscopy (TERS) combines scanning probe microscopy with Raman spectroscopy, taking advantage of apertureless near-field optics. A plasmonic structure at the apex of a sharp tip provides signal amplification required for chemical imaging. Plasmonic structure characteristics such as roughness, shape, and radius determine the spatial resolution and signal enhancement. Unfortunately, noble metal nanostructures have limited lifetimes due to mechanical, chemical, and thermal degradation. Lifetime extension requires slowing degradation processes while minimizing unfavorable influences on the optical response. An ultrathin SiOx protective coating provides lifetime improvement of silver plasmonic nanostructures on SPM tips. Controlled physical vapor deposition (PVD) of Al can be used to create ultrathin (˜2-3 nm) Al2O3 coatings that improve significantly the stability and wear resistance of plasmonics structures without substantial degradation of optical properties. Such a coating completely prevented decay in plasmonic activity after 40 days of use.

  17. Evaluation of radioisotope tracer and activation analysis techniques for contamination monitoring in space environment simulation chambers

    NASA Technical Reports Server (NTRS)

    Smathers, J. B.; Kuykendall, W. E., Jr.; Wright, R. E., Jr.; Marshall, J. R.

    1973-01-01

    Radioisotope measurement techniques and neutron activation analysis are evaluated for use in identifying and locating contamination sources in space environment simulation chambers. The alpha range method allows the determination of total contaminant concentration in vapor state and condensate state. A Cf-252 neutron activation analysis system for detecting oils and greases tagged with stable elements is described. While neutron activation analysis of tagged contaminants offers specificity, an on-site system is extremely costly to implement and provides only marginal detection sensitivity under even the most favorable conditions.

  18. Multiple apolipoprotein kinetics measured in human HDL by high-resolution/accurate mass parallel reaction monitoring.

    PubMed

    Singh, Sasha A; Andraski, Allison B; Pieper, Brett; Goh, Wilson; Mendivil, Carlos O; Sacks, Frank M; Aikawa, Masanori

    2016-04-01

    Endogenous labeling with stable isotopes is used to study the metabolism of proteins in vivo. However, traditional detection methods such as GC/MS cannot measure tracer enrichment in multiple proteins simultaneously, and multiple reaction monitoring MS cannot measure precisely the low tracer enrichment in slowly turning-over proteins as in HDL. We exploited the versatility of the high-resolution/accurate mass (HR/AM) quadrupole Orbitrap for proteomic analysis of five HDL sizes. We identified 58 proteins in HDL that were shared among three humans and that were organized into five subproteomes according to HDL size. For seven of these proteins, apoA-I, apoA-II, apoA-IV, apoC-III, apoD, apoE, and apoM, we performed parallel reaction monitoring (PRM) to measure trideuterated leucine tracer enrichment between 0.03 to 1.0% in vivo, as required to study their metabolism. The results were suitable for multicompartmental modeling in all except apoD. These apolipoproteins in each HDL size mainly originated directly from the source compartment, presumably the liver and intestine. Flux of apolipoproteins from smaller to larger HDL or the reverse contributed only slightly to apolipoprotein metabolism. These novel findings on HDL apolipoprotein metabolism demonstrate the analytical breadth and scope of the HR/AM-PRM technology to perform metabolic research. PMID:26862155

  19. High-Resolution Simulations of Gas-Solids Jet Penetration Into a High Density Riser Flow

    SciTech Connect

    Li, Tingwen

    2011-05-01

    High-resolution simulations of a gas-solids jet in a 0.3 m diameter and 15.9 m tall circulating fluidized bed (CFB) riser were conducted with the open source software-MFIX. In the numerical simulations, both gas and solids injected through a 1.6 cm diameter radial-directed tube 4.3 m above the bottom distributor were tracked as tracers, which enable the analysis of the characteristics of a two-phase jet. Two jetting gas velocities of 16.6 and 37.2 m/s were studied with the other operating conditions fixed. Reasonable flow hydrodynamics with respect to overall pressure drop, voidage, and solids velocity distributions were predicted. Due to the different dynamic responses of gas and particles to the crossflow, a significant separation of gas and solids within the jet region was predicted for both cases. In addition, the jet characteristics based on tracer concentration and tracer mass fraction profiles at different downstream levels are discussed. Overall, the numerical predictions compare favorably to the experimental measurements made at NETL.

  20. High Resolution X-ray Imaging

    NASA Technical Reports Server (NTRS)

    Cash, Webster

    2002-01-01

    NAG5-5020 covered a period of 7.5 years during which a great deal of progress was made in x-ray optical techniques under this grant. We survived peer review numerous times during the effort to keep the grant going. In 1994, when the grant started we were actively pursuing the application of spherical mirrors to improving x-ray telescopes. We had found that x-ray detectors were becoming rapidly more sophisticated and affordable, but that x-ray telescopes were only being improved through the intense application of money within the AXAF program. Clearly new techniques for the future were needed. We were successful in developing and testing at the HELSTF facility in New Mexico a four reflection coma-corrected telescope made from spheres. We were able to demonstrate 0.3 arcsecond resolution, almost to the diffraction limit of the system. The community as a whole was, at that time, not particularly interested in looking past AXAF (Chandra) and the effort needed to evolve. Since we had reached the diffraction limit using non-Wolter optics we then decided to see if we could build an x-ray interferometer in the laboratory. In the lab the potential for improved resolution was substantial. If synthetic aperture telescopes could be built in space, then orders of magnitude improvement would become feasible. In 1998 NASA, under the direction of Dr Nick White of Goddard, started a study to assess the potential and feasibility of x-ray interferometry in space. My work became of central interest to the committee because it indicated that such was possible. In early 1999 we had the breakthrough that allowed us build a practical interferometer. By using flats and hooking up with the Marshall Space Flight Center facilities we were able to demonstrate fringes at 1.25keV on a one millimeter baseline. This actual laboratory demonstration provided the solid proof of concept that NASA needed. As the year progressed the future of x-ray astronomy jelled around the Maxim program. Maxim is a

  1. High Resolution X-ray Imaging

    NASA Technical Reports Server (NTRS)

    Cash, Webster

    2002-01-01

    NAG5-5020 covered a period of 7.5 years during which a great deal of progress was made in x-ray optical techniques under this grant. We survived peer review numerous times during the effort to keep the grant going. In 1994, when the grant started we were actively pursuing the application of spherical mirrors to improving x-ray telescopes. We had found that x-ray detectors were becoming rapidly more sophisticated and affordable, but that x-ray telescopes were only being improved through the intense application of money within the AXAF program. Clearly new techniques for the future were needed. We were successful in developing and testing at the HELSTF facility in New Mexico a four reflection coma-corrected telescope made from spheres. We were able to demonstrate 0.3 arcsecond resolution, almost to the diffraction limit of the system. The community as a whole was, at that time, not particularly interested in looking past AXAF (Chandra) and the effort needed to evolve. Since we had reached the diffraction limit using non-Wolter optics we then decided to see if we could build an x-ray interferometer in the laboratory. In the lab the potential for improved resolution was substantial. If synthetic aperture telescopes could be built in space, then orders of magnitude improvement would become feasible. In 1998 NASA, under the direction of Dr. Nick White of Goddard, started a study to assess the potential and feasibility of x-ray interferometry in space. My work became of central interest to the committee because it indicated that such was possible. In early 1999 we had the breakthrough that allowed us build a practical interferometer. By using flats and hooking up with the Marshall Space Flight Center facilities we were able to demonstrate fringes at 1.25keV on a one millimeter baseline. This actual laboratory demonstration provided the solid proof of concept that NASA needed.

  2. A high resolution global scale groundwater model

    NASA Astrophysics Data System (ADS)

    de Graaf, I. E.; Sutanudjaja, E.; Van Beek, L. P.; Bierkens, M. F.

    2013-12-01

    As the world's largest accessible source of freshwater, groundwater plays a vital role in satisfying the basic needs of human society. It serves as a primary source of drinking water and also supplies water for agricultural and industrial activities. During times of drought, the large natural groundwater storage provides a buffer against water shortage and sustains flows to rivers and wetlands, supporting ecosystem habitats and biodiversity. Yet, the current generation of global scale hydrological models (GHMs) do not include a groundwater flow component, although it is a crucial part of the hydrological cycle. Thus, a realistic physical representation of the groundwater system that allows for the simulation of groundwater head dynamics and lateral flows is essential for GHMs that increasingly run at finer resolution. In this study we present a transient global groundwater model with a resolution of 5 arc-minutes (approximately 10 km at the equator) using MODFLOW (McDonald and Harbaugh, 1988). Aquifer schematization and properties of this groundwater model were developed from available global lithological maps and datasets (Dürr et al., 2005; Gleeson et al., 2010; Hartmann and Moosdorf, 2013) combined with information about e.g. aquifer thickness and presence of less permeable, impermeable, and semi-impermeable layers. For the parameterization, we relied entirely on available global datasets and did not calibrate the model so that it can equally be expanded to data poor environments. We forced the groundwater model with the output from the global hydrological model PCR-GLOBWB (van Beek et al., 2011), specifically the net groundwater recharge and average surface water levels derived from routed channel discharge. We validated simulated groundwater heads with observations, from North America and Australia, resulting in a coefficient of determination of 0.8 and 0.7 respectively. This shows that it is feasible to build a global groundwater model using best available

  3. A high resolution global scale groundwater model

    NASA Astrophysics Data System (ADS)

    de Graaf, I. E. M.; Sutanudjaja, E. H.; van Beek, L. P. H.; Bierkens, M. F. P.

    2014-05-01

    Groundwater is the world's largest accessible source of fresh water. It plays a vital role in satisfying needs for drinking water, agriculture and industrial activities. During times of drought groundwater sustains baseflow to rivers and wetlands, thereby supporting ecosystems. Most global scale hydrological models (GHMs) do not include a groundwater flow component, mainly due to lack of geohydrological data at the global scale. For the simulation of lateral flow and groundwater head dynamics a realistic physical representation of the groundwater system is needed, especially for GHMs that run at finer resolution. In this study we present a global scale groundwater model (run at 6' as dynamic steady state) using MODFLOW to construct an equilibrium water table at its natural state as the result of long-term climatic forcing. The aquifer schematization and properties were based on available global datasets of lithology and transmissivities combined with estimated aquifer thickness of an upper unconfined aquifer. The model is forced with outputs from the land-surface model PCR-GLOBWB, specifically with net recharge and surface water levels. A sensitivity analysis, in which the model was run with various parameter settings, showed variation in saturated conductivity causes most of the groundwater level variations. Simulated groundwater heads were validated against reported piezometer observations. The validation showed that groundwater depths are reasonably well simulated for many regions of the world, especially for sediment basins (R2 = 0.95). The simulated regional scale groundwater patterns and flowpaths confirm the relevance of taking lateral groundwater flow into account in GHMs. Flowpaths show inter-basin groundwater flow that can be a significant part of a basins water budget and helps to sustain river baseflow, explicitly during times of droughts. Also important aquifer systems are recharged by inter-basin groundwater flows that positively affect water

  4. High Resolution X-Ray Explorer (HIREX)

    NASA Technical Reports Server (NTRS)

    Golub, Leon

    1999-01-01

    SAO has carried out a study to determine the feasibility of building an orbiting telescope capable of resolving 7 km structure on the Sun. In order to achieve the required imaging the telescope must have a resolution 0.01 arcsec. This fact challenges the state of the art of orbiting telescopes in several areas: mirror figuring; optical metrology; optical mounting; mirror figure control; system alignment; optical stability; observatory pointing; and image stability image stability. The telescope design concept is based on a 0.6m Cassegrain-style telescope with a 240 meter effective focal length. This is achieved with 2 mirrors supported at opposite ends of a 27 m space-deployable boom. The telescope mirrors are coated with multilayers designed to reflect a broad XUV passband. A third, small mirror, near the focal plane performs the function of selecting the narrow band that is finally imaged. Image stabilization to the 0.005 a,rcsec level is achieved by active control of the secondary mirror. The primary mirror is held unadjustably to the spacecraft, its pointing set by the space- craft orientation. The secondary mirror is mounted on a 6-axis stage that permits its position to be changed to align the telescope in space. The stage is intended for intermittent adjustment, both because of its speed of travel, and the TBD alignment procedure. The third mirror is called the TXI (Tuneable X-ray Imager). It is mounted on a gimbal that permits it to be tipped over a 60 degree range, selecting between the individual wavelengths in the initial bandpass. It can also rotated completely out of the way to allow the full, broadband EUV flux to strike the focal plane.

  5. A high resolution global scale groundwater model

    NASA Astrophysics Data System (ADS)

    de Graaf, Inge; Sutanudjaja, Edwin; van Beek, Rens; Bierkens, Marc

    2014-05-01

    As the world's largest accessible source of freshwater, groundwater plays a vital role in satisfying the basic needs of human society. It serves as a primary source of drinking water and supplies water for agricultural and industrial activities. During times of drought, groundwater storage provides a large natural buffer against water shortage and sustains flows to rivers and wetlands, supporting ecosystem habitats and biodiversity. Yet, the current generation of global scale hydrological models (GHMs) do not include a groundwater flow component, although it is a crucial part of the hydrological cycle. Thus, a realistic physical representation of the groundwater system that allows for the simulation of groundwater head dynamics and lateral flows is essential for GHMs that increasingly run at finer resolution. In this study we present a global groundwater model with a resolution of 5 arc-minutes (approximately 10 km at the equator) using MODFLOW (McDonald and Harbaugh, 1988). With this global groundwater model we eventually intend to simulate the changes in the groundwater system over time that result from variations in recharge and abstraction. Aquifer schematization and properties of this groundwater model were developed from available global lithological maps and datasets (Dürr et al., 2005; Gleeson et al., 2010; Hartmann and Moosdorf, 2013), combined with our estimate of aquifer thickness for sedimentary basins. We forced the groundwater model with the output from the global hydrological model PCR-GLOBWB (van Beek et al., 2011), specifically the net groundwater recharge and average surface water levels derived from routed channel discharge. For the parameterization, we relied entirely on available global datasets and did not calibrate the model so that it can equally be expanded to data poor environments. Based on our sensitivity analysis, in which we run the model with various hydrogeological parameter settings, we observed that most variance in groundwater

  6. The dynamic solar chromosphere: recent advances from high resolution telescopes

    NASA Astrophysics Data System (ADS)

    Tziotziou, Konstantinos; Tsiropoula, Georgia

    This review focuses on the solar chromosphere, a very inhomogeneous and dynamic layer that exhibits phenomena on a large range of spatial and temporal scales. High-resolution observa-tions from existing telescopes (DST, SST, DOT), as well as long-duration observations with Hinode's SOT employing lines such as the Ca II infrared lines, the Ca II HK and above all the Hα line reveal an incredibly rich, dynamic and highly structured environment, both in quiet and active regions. The fine-structure chromosphere, is mainly constituted by fibrilar features that connect various parts of active regions or span across network cell interiors. We discuss this highly dynamical solar chromosphere, especially below the magnetic canopy, which is gov-erned by flows reflecting both the complex geometry and dynamics of the magnetic field and the propagation and dissipation of waves in the different atmospheric layers. A comprehensive view of the fine-structure chromosphere requires deep understanding of the physical processes involved, investigation of the intricate link with structures/processes at lower photospheric lev-els and analysis of its impact on the mass and energy transport to higher atmospheric layers through flows resulting from different physical processes such as magnetic reconnection and waves. Furthermore, we assess the challenges facing theory and numerical modelling which require the inclusion of several physical ingredients, such as non-LTE and three-dimensional numerical simulations.

  7. High-resolution EEG (HR-EEG) and magnetoencephalography (MEG).

    PubMed

    Gavaret, M; Maillard, L; Jung, J

    2015-03-01

    High-resolution EEG (HR-EEG) and magnetoencephalography (MEG) allow the recording of spontaneous or evoked electromagnetic brain activity with excellent temporal resolution. Data must be recorded with high temporal resolution (sampling rate) and high spatial resolution (number of channels). Data analyses are based on several steps with selection of electromagnetic signals, elaboration of a head model and use of algorithms in order to solve the inverse problem. Due to considerable technical advances in spatial resolution, these tools now represent real methods of ElectroMagnetic Source Imaging. HR-EEG and MEG constitute non-invasive and complementary examinations, characterized by distinct sensitivities according to the location and orientation of intracerebral generators. In the presurgical assessment of drug-resistant partial epilepsies, HR-EEG and MEG can characterize and localize interictal activities and thus the irritative zone. HR-EEG and MEG often yield significant additional data that are complementary to other presurgical investigations and particularly relevant in MRI-negative cases. Currently, the determination of the epileptogenic zone and functional brain mapping remain rather less well-validated indications. In France, in 2014, HR-EEG is now part of standard clinical investigation of epilepsy, while MEG remains a research technique. PMID:25648821

  8. Monitoring a quarry using high resolution data and GIS techniques

    NASA Astrophysics Data System (ADS)

    Nikolakopoulos, Konstantinos G.; Tsombos, P. I.; Vaiopoulos, A. D.

    2010-10-01

    Active quarries near to urban centers are at the same time a necessity but also a source of pollution. Necessity as they supply to the construction companies the necessary aggregates and source of pollution as they affect biodiversity, vegetation cover and threaten water resources. The objective of this work is to indicate a monitoring methodology in order to survey the present state of the quarry sites and their evolution in time, which are the basic data needed to implement an adequate land reclamation project. The land monitoring has been realised both by using remote sensing techniques, supported by a Geographic Information System of the studied area, and by in situ surveying. The in situ surveying was able to assess the capability of the remote sensing model to describe the state of each site. High resolution satellite data from different sensors were used for the monitoring of an active quarry. More especially, Ikonos Quickbird, and Worldiew data were orthorectified and inserted in a GIS database in order to quantify the changes.

  9. Enhancing the activation of silicon carbide tracer particles for PEPT applications using gas-phase deposition of alumina at room temperature and atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Valdesueiro, D.; Garcia-Triñanes, P.; Meesters, G. M. H.; Kreutzer, M. T.; Gargiuli, J.; Leadbeater, T. W.; Parker, D. J.; Seville, J. P. K.; van Ommen, J. R.

    2016-01-01

    We have enhanced the radio-activation efficiency of SiC (silicon carbide) particles, which by nature have a poor affinity towards 18F ions, to be employed as tracers in studies using PEPT (Positron Emission Particle Tracking). The resulting SiC-Al2O3 core-shell structure shows a good labelling efficiency, comparable to γ-Al2O3 tracer particles, which are commonly used in PEPT. The coating of the SiC particles was carried at 27±3 °C and 1 bar in a fluidized bed reactor, using trimethylaluminium and water as precursors, by a gas phase technique similar to atomic layer deposition. The thickness of the alumina films, which ranged from 5 to 500 nm, was measured by elemental analysis and confirmed with FIB-TEM (focused ion beam - transmission electron microscope), obtaining consistent results from both techniques. By depositing such a thin film of alumina, properties that influence the hydrodynamic behaviour of the SiC particles, such as size, shape and density, are hardly altered, ensuring that the tracer particle shows the same flow behaviour as the other particles. The paper describes a general method to improve the activation efficiency of materials, which can be applied for the production of tracer particles for many other applications too.

  10. High resolution atomic force microscopy of double-stranded RNA

    NASA Astrophysics Data System (ADS)

    Ares, Pablo; Fuentes-Perez, Maria Eugenia; Herrero-Galán, Elías; Valpuesta, José M.; Gil, Adriana; Gomez-Herrero, Julio; Moreno-Herrero, Fernando

    2016-06-01

    Double-stranded (ds) RNA mediates the suppression of specific gene expression, it is the genetic material of a number of viruses, and a key activator of the innate immune response against viral infections. The ever increasing list of roles played by dsRNA in the cell and its potential biotechnological applications over the last decade has raised an interest for the characterization of its mechanical properties and structure, and that includes approaches using Atomic Force Microscopy (AFM) and other single-molecule techniques. Recent reports have resolved the structure of dsDNA with AFM at unprecedented resolution. However, an equivalent study with dsRNA is still lacking. Here, we have visualized the double helix of dsRNA under near-physiological conditions and at sufficient resolution to resolve the A-form sub-helical pitch periodicity. We have employed different high-sensitive force-detection methods and obtained images with similar spatial resolution. Therefore, we show here that the limiting factors for high-resolution AFM imaging of soft materials in liquid medium are, rather than the imaging mode, the force between the tip and the sample and the sharpness of the tip apex.Double-stranded (ds) RNA mediates the suppression of specific gene expression, it is the genetic material of a number of viruses, and a key activator of the innate immune response against viral infections. The ever increasing list of roles played by dsRNA in the cell and its potential biotechnological applications over the last decade has raised an interest for the characterization of its mechanical properties and structure, and that includes approaches using Atomic Force Microscopy (AFM) and other single-molecule techniques. Recent reports have resolved the structure of dsDNA with AFM at unprecedented resolution. However, an equivalent study with dsRNA is still lacking. Here, we have visualized the double helix of dsRNA under near-physiological conditions and at sufficient resolution to

  11. Methodology of high-resolution photography for mural condition database

    NASA Astrophysics Data System (ADS)

    Higuchi, R.; Suzuki, T.; Shibata, M.; Taniguchi, Y.

    2015-08-01

    Digital documentation is one of the most useful techniques to record the condition of cultural heritage. Recently, high-resolution images become increasingly useful because it is possible to show general views of mural paintings and also detailed mural conditions in a single image. As mural paintings are damaged by environmental stresses, it is necessary to record the details of painting condition on high-resolution base maps. Unfortunately, the cost of high-resolution photography and the difficulty of operating its instruments and software have commonly been an impediment for researchers and conservators. However, the recent development of graphic software makes its operation simpler and less expensive. In this paper, we suggest a new approach to make digital heritage inventories without special instruments, based on our recent our research project in Üzümlü church in Cappadocia, Turkey. This method enables us to achieve a high-resolution image database with low costs, short time, and limited human resources.

  12. A compact, light weight, high resolution electron monochromator

    NASA Astrophysics Data System (ADS)

    Goembel, L.; Doering, J. P.

    1995-06-01

    A high resolution electron monochromator that incorporates Vespel polyimide plastic in its construction is described. A great saving in bulk can be realized by mounting the electron optical elements in Vespel tubes rather than mounting them by traditional means.

  13. High Resolution CryoFESEM of Microbial Surfaces

    NASA Astrophysics Data System (ADS)

    Erlandsen, Stanley; Lei, Ming; Martin-Lacave, Ines; Dunny, Gary; Wells, Carol

    2003-08-01

    The outer surfaces of three microorganisms, Giardia lamblia, Enterococcus faecalis, and Proteus mirabilis, were investigated by cryo-immobilization followed by sublimation of extracellular ice and cryocoating with either Pt alone or Pt plus carbon. Cryocoated samples were examined at [minus sign]125°C in either an in-lens field emission SEM or a below-the-lens field emission SEM. Cryocoating with Pt alone was sufficient for low magnification observation, but attempts to do high-resolution imaging resulted in radiolysis and cracking of the specimen surface. Double coating with Pt and carbon, in combination with high resolution backscatter electron detectors, enabled high-resolution imaging of the glycocalyx of bacteria, revealing a sponge-like network over the surface. High resolution examination of bacterial flagella also revealed a periodic substructure. Common artifacts included radiolysis leading to “cracking” of the surface, and insufficient deposition of Pt resulting in the absence of detectable surface topography.

  14. Update on High-Resolution Geodetically Controlled LROC Polar Mosaics

    NASA Astrophysics Data System (ADS)

    Archinal, B.; Lee, E.; Weller, L.; Richie, J.; Edmundson, K.; Laura, J.; Robinson, M.; Speyerer, E.; Boyd, A.; Bowman-Cisneros, E.; Wagner, R.; Nefian, A.

    2015-10-01

    We describe progress on high-resolution (1 m/pixel) geodetically controlled LROC mosaics of the lunar poles, which can be used for locating illumination resources (for solar power or cold traps) or landing site and surface operations planning.

  15. High resolution difference schemes for compressible gas dynamics

    SciTech Connect

    Woodward, P.; Colella, P.

    1980-07-30

    The advantages and disadvantages of four new high-resolution difference schemes, namely the von Neumann-Richtmyer, Godunovs, MUSCL and Glimms, for mathematically representing physical conditions in compressible gas flows are compared. (LCL)

  16. AVHRR/1-FM Advanced Very High Resolution Radiometer

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The advanced very high resolution radiometer is discussed. The program covers design, construction, and test of a breadboard model, engineering model, protoflight model, mechanical/structural model, and a life test model. Special bench test and calibration equipment was developed for use on the program. The flight model program objectives were to fabricate, assemble and test four of the advanced very high resolution radiometers along with a bench cooler and collimator.

  17. CURRENT HELICITY OF ACTIVE REGIONS AS A TRACER OF LARGE-SCALE SOLAR MAGNETIC HELICITY

    SciTech Connect

    Zhang, H.; Gao, Y.; Xu, H.; Moss, D.; Kleeorin, N.; Rogachevskii, I.; Kuzanyan, K.; Sokoloff, D.

    2012-05-20

    We demonstrate that the current helicity observed in solar active regions traces the magnetic helicity of the large-scale dynamo generated field. We use an advanced two-dimensional mean-field dynamo model with dynamo saturation based on the evolution of the magnetic helicity and algebraic quenching. For comparison, we also studied a more basic two-dimensional mean-field dynamo model with simple algebraic alpha-quenching only. Using these numerical models we obtained butterfly diagrams both for the small-scale current helicity and also for the large-scale magnetic helicity, and compared them with the butterfly diagram for the current helicity in active regions obtained from observations. This comparison shows that the current helicity of active regions, as estimated by -A {center_dot} B evaluated at the depth from which the active region arises, resembles the observational data much better than the small-scale current helicity calculated directly from the helicity evolution equation. Here B and A are, respectively, the dynamo generated mean magnetic field and its vector potential. A theoretical interpretation of these results is given.

  18. Prediction of Therapy Tumor-Absorbed Dose Estimates in I-131 Radioimmunotherapy Using Tracer Data Via a Mixed-Model Fit to Time Activity

    PubMed Central

    Koral, Kenneth F.; Avram, Anca M.; Kaminski, Mark S.; Dewaraja, Yuni K.

    2012-01-01

    Abstract Background For individualized treatment planning in radioimmunotherapy (RIT), correlations must be established between tracer-predicted and therapy-delivered absorbed doses. The focus of this work was to investigate this correlation for tumors. Methods The study analyzed 57 tumors in 19 follicular lymphoma patients treated with I-131 tositumomab and imaged with SPECT/CT multiple times after tracer and therapy administrations. Instead of the typical least-squares fit to a single tumor's measured time-activity data, estimation was accomplished via a biexponential mixed model in which the curves from multiple subjects were jointly estimated. The tumor-absorbed dose estimates were determined by patient-specific Monte Carlo calculation. Results The mixed model gave realistic tumor time-activity fits that showed the expected uptake and clearance phases even with noisy data or missing time points. Correlation between tracer and therapy tumor-residence times (r=0.98; p<0.0001) and correlation between tracer-predicted and therapy-delivered mean tumor-absorbed doses (r=0.86; p<0.0001) were very high. The predicted and delivered absorbed doses were within±25% (or within±75 cGy) for 80% of tumors. Conclusions The mixed-model approach is feasible for fitting tumor time-activity data in RIT treatment planning when individual least-squares fitting is not possible due to inadequate sampling points. The good correlation between predicted and delivered tumor doses demonstrates the potential of using a pretherapy tracer study for tumor dosimetry-based treatment planning in RIT. PMID:22947086

  19. Fiber optic cable-based high-resolution, long-distance VGA extenders

    NASA Astrophysics Data System (ADS)

    Rhee, Jin-Geun; Lee, Iksoo; Kim, Heejoon; Kim, Sungjoon; Koh, Yeon-Wan; Kim, Hoik; Lim, Jiseok; Kim, Chur; Kim, Jungwon

    2013-02-01

    Remote transfer of high-resolution video information finds more applications in detached display applications for large facilities such as theaters, sports complex, airports, and security facilities. Active optical cables (AOCs) provide a promising approach for enhancing both the transmittable resolution and distance that standard copper-based cables cannot reach. In addition to the standard digital formats such as HDMI, the high-resolution, long-distance transfer of VGA format signals is important for applications where high-resolution analog video ports should be also supported, such as military/defense applications and high-resolution video camera links. In this presentation we present the development of a compressionless, high-resolution (up to WUXGA, 1920x1200), long-distance (up to 2 km) VGA extenders based on serialized technique. We employed asynchronous serial transmission and clock regeneration techniques, which enables lower cost implementation of VGA extenders by removing the necessity for clock transmission and large memory at the receiver. Two 3.125-Gbps transceivers are used in parallel to meet the required maximum video data rate of 6.25 Gbps. As the data are transmitted asynchronously, 24-bit pixel clock time stamp is employed to regenerate video pixel clock accurately at the receiver side. In parallel to the video information, stereo audio and RS-232 control signals are transmitted as well.

  20. One millimetre makes the difference: high-resolution analysis of methane-oxidizing bacteria and their specific activity at the oxic–anoxic interface in a flooded paddy soil

    PubMed Central

    Reim, Andreas; Lüke, Claudia; Krause, Sascha; Pratscher, Jennifer; Frenzel, Peter

    2012-01-01

    Aerobic methane-oxidizing bacteria (MOB) use a restricted substrate range, yet >30 species-equivalent operational taxonomical units (OTUs) are found in one paddy soil. How these OTUs physically share their microhabitat is unknown. Here we highly resolved the vertical distribution of MOB and their activity. Using microcosms and cryosectioning, we sub-sampled the top 3-mm of a water-saturated soil at near in situ conditions in 100-μm steps. We assessed the community structure and activity using the particulate methane monooxygenase gene pmoA as a functional and phylogenetic marker by terminal restriction fragment length polymorphism (t-RFLP), a pmoA-specific diagnostic microarray, and cloning and sequencing. pmoA genes and transcripts were quantified using competitive reverse transcriptase PCR combined with t-RFLP. Only a subset of the methanotroph community was active. Oxygen microprofiles showed that 89% of total respiration was confined to a 0.67-mm-thick zone immediately above the oxic–anoxic interface, most probably driven by methane oxidation. In this zone, a Methylobacter-affiliated OTU was highly active with up to 18 pmoA transcripts per cell and seemed to be adapted to oxygen and methane concentrations in the micromolar range. Analysis of transcripts with a pmoA-specific microarray found a Methylosarcina-affiliated OTU associated with the surface zone. High oxygen but only nanomolar methane concentrations at the surface suggested an adaptation of this OTU to oligotrophic conditions. No transcripts of type II methanotrophs (Methylosinus, Methylocystis) were found, which indicated that this group was represented by resting stages only. Hence, different OTUs within a single guild shared the same microenvironment and exploited different niches. PMID:22695859

  1. An electrochemical one-step system for assaying methyltransferase activity based on transport of a quantum dot signaling tracer.

    PubMed

    Baek, Songyi; Won, Byoung Yeon; Park, Ki Soo; Park, Hyun Gyu

    2013-11-15

    A one-step, electrochemical method for assaying methyltransferase (MTase) activity, based on the convective transport of a quantum dot (QD) signaling tracer, has been developed. The assay chip used in this system was prepared by modifying a gold matrix with CdSe/ZnS QD-tagged dsDNA, which contains a specific methylation site (5'-GATC-3') recognized by MTase. Treatment of the chip with DNA adenine methylation (Dam) MTase, generates a methylated sequence (5'-GAmTC-3') within the dsDNA. The methylated dsDNA is then subjected to a cleavage reaction, induced by DpnI, which leads to release from the gold matrix of a DNA fragment tethered to a QD. Detection of the released QD, using square wave anodic stripping voltammetry (SWASV) on a glassy carbon (GC) electrode, enables the reliable quantitation of the methylated DNA. Because it is accomplished in a simple and convenient one step and does not require any complicated secondary or tedious washing steps, the new assay method holds great promise for epigenetic analysis in facility-limited environments or point-of-care testing (POCT) applications. PMID:23777705

  2. CeBr3 as a Room-Temperature, High-Resolution Gamma-Ray Detector

    SciTech Connect

    Paul Guss, Michael Reed, Ding Yuan, Alexis Reed, and Sanjoy Mukhopadhyay

    2009-09-01

    Cerium bromide (CeBr3) has become a material of interest in the race for high-resolution gamma-ray spectroscopy at room temperature. This investigation quantified the potential of CeBr3 as a room temperature, high-resolution gamma-ray detector. The performance of CeBr3 crystals was compared to other scintillation crystals of similar dimensions and detection environments. Comparison of self-activity of CeBr3 to cerium-doped lanthanum tribromide (LaBr3:Ce) was performed. Energy resolution and relative intrinsic efficiency were measured and are presented.

  3. High performance simulation of environmental tracers in heterogeneous domains.

    PubMed

    Gardner, William P; Hammond, Glenn; Lichtner, Peter

    2015-04-01

    In this study, we use PFLOTRAN, a highly scalable, parallel, flow, and reactive transport code to simulate the concentrations of 3H, 3He, CFC-11, CFC-12, CFC-113, SF6, 39Ar, and the mean groundwater age in heterogeneous fields on grids with an excess of 10 million nodes. We utilize this computational platform to simulate the concentration of multiple tracers in high-resolution, heterogeneous 2D and 3D domains, and calculate tracer-derived ages. Tracer-derived ages show systematic biases toward younger ages when the groundwater age distribution contains water older than the maximum tracer age. The deviation of the tracer-derived age distribution from the true groundwater age distribution increases with increasing heterogeneity of the system. However, the effect of heterogeneity is diminished as the mean travel time gets closer to the tracer age limit. Age distributions in 3D domains differ significantly from 2D domains. 3D simulations show decreased mean age, and less variance in age distribution for identical heterogeneity statistics. High-performance computing allows for investigation of tracer and groundwater age systematics in high-resolution domains, providing a platform for understanding and utilizing environmental tracer and groundwater age information in heterogeneous 3D systems. PMID:24372403

  4. Goddard High Resolution Spectrograph SV/GTO Project

    NASA Technical Reports Server (NTRS)

    Ebbets, Dennis

    1999-01-01

    Contract number NAS5-30433, known at Ball Aerospace as the GHRS SV/GTO project, supported our participation in the post-launch activities of the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope. The period of performance was December 1988 through December 1998. The contract supported the involvement of Dr Dennis Ebbets in the work of the GHRS Investigation Definition Team, and several of the Ball people in the documentation and publication of results. Three main categories of tasks were covered by this contract; in-orbit calibration of the GHRS, guaranteed time observations, and education and public outreach. The nature and accomplishments of these tasks are described in the report. This summary makes many references to publications in the scientific and technical literature. Appendix A is extracted from a complete bibliography, and lists those papers that are directly related to work performed under this GHRS contract. The tasks related to the in-orbit calibration of the GHRS were by far the largest responsibility during the first six years of the project. During this period Dr. Ebbets was responsible for the definition of calibration requirements, design of experiments, preparation of observing proposals, tracking their implementation and execution, and coordinating the analysis and publication of the results. Prior to the launch of HST in 1990 the observing proposals were developed in cooperation with the scientists on the GHRS DDT, engineers at Ball Aerospace, the operations staff at the STScI, and project coordinators at GSFC.

  5. Calibration of the high resolution spectrometer barrel calorimeter at PEP

    SciTech Connect

    Loos, J.S.

    1983-01-01

    The High-Resolution Spectrometer (HRS) is a general-purpose detector for the study of high-energy electron-positron collisions. The HRS has been in data-taking operation since early 1982. This report covers the calibration of the barrel shower counter system. The barrel system consists of 40 modules placed in a circular arch having a mean radius of 2.1 m. Each module covers an azimuthal wedge of 9 degrees and has an active length of 3.0 m. There are three independent sections: (1) an inner sandwich of Pb and scintillator (NE110) of thickness 3 r.1., (2) a plane of 14 proportional wire cells equipped with charge-division read-out, and (3) an outer sandwich of Pb and scintillator (NE114) of thickness 8. r. 1. The light from the sandwich section is collected at both ends and is passed through long acrylic pipes (5 cm diameter, 162 cm long) to photomultipliers (Amperex XP2230) mounted outside the magnet steel.

  6. High Resolution Spectroscopy of Two FK Comae Stars

    NASA Astrophysics Data System (ADS)

    Linsky, Jeffrey L.

    The FK Comae stars are a class of extremely rapidly rotating G-K giants that exhibit among the brightest UV and X-ray emission seen in late type stars. Previous IUE and optical observations have indicated that the activity (the extreme surface fluxes) in FK Comae may be qualitatively different from that in "normal" late type stars, and that the other four members of the class are far less bizarre than FK Comae itself. A definitive method for determining the structure of the outer atmospheres of these stars, and deciding whether the heating mechanism is normal chromospheric heating or accretion heating is by analysis of high resolution SWP spectra. We propose, in collaboration with S. Rucinski, to obtain 16-20 hour collaborative NASA-ESA SWP-HI spectra of FK Comae, which exhibits Hot and MgII line widths of ˜500 kms^-1, and HD 36705, which appears to be a far less bizarre member of this class. These observations would be the first high dispersion SWP spectra ever obtained of FK Comae stars.

  7. High resolution seismic stratigraphy of Tampa Bay, Florida

    SciTech Connect

    Tihansky, A.B.; Hine, A.C.; Locker, S.D.; Doyle, L.D. . Dept. of Marine Science)

    1993-03-01

    Tampa Bay is one of two large embayments that interrupt the broad, regional nature of the carbonate ramp of the west coast of the Florida carbonate platform. It is believed to have formed as a result of preferential dissolution of the Cenozoic limestones beneath it. Highly reactive freshwater systems became hydrologically focused in the bay region as the surface and groundwater systems established themselves during sea-level lowstands. This weakening of the underlying limestone resulted in extensive karstification, including warping, subsidence, sinkhole and spring formation. Over 120 miles of high resolution seismic reflection data were collected within Tampa Bay. This record has been tied into 170 core borings taken from within the bay. This investigation has found three major seismic stratigraphic sequences beneath the bay. The lowermost sequence is probably of Miocene age. Its surface is highly irregular due to erosion and dissolution and exhibits a great deal of vertical relief as well as gentler undulations or warping. Much of the middle sequence consists of low angle clinoforms that gently downlap and fill in the underlying karst features. The uppermost sequence is a discontinuous unit comprised of horizontal to low angle clinoforms that are local in their extent. The recent drainage and sedimentation patterns within the bay area are related to the underlying structure controlled by the Miocene karst activity.

  8. High-resolution multimodal clinical multiphoton tomography of skin

    NASA Astrophysics Data System (ADS)

    König, Karsten

    2011-03-01

    This review focuses on multimodal multiphoton tomography based on near infrared femtosecond lasers. Clinical multiphoton tomographs for 3D high-resolution in vivo imaging have been placed into the market several years ago. The second generation of this Prism-Award winning High-Tech skin imaging tool (MPTflex) was introduced in 2010. The same year, the world's first clinical CARS studies have been performed with a hybrid multimodal multiphoton tomograph. In particular, non-fluorescent lipids and water as well as mitochondrial fluorescent NAD(P)H, fluorescent elastin, keratin, and melanin as well as SHG-active collagen has been imaged with submicron resolution in patients suffering from psoriasis. Further multimodal approaches include the combination of multiphoton tomographs with low-resolution wide-field systems such as ultrasound, optoacoustical, OCT, and dermoscopy systems. Multiphoton tomographs are currently employed in Australia, Japan, the US, and in several European countries for early diagnosis of skin cancer, optimization of treatment strategies, and cosmetic research including long-term testing of sunscreen nanoparticles as well as anti-aging products.

  9. High-Resolution Observations of Sympathetic Filament Eruptions by NVST

    NASA Astrophysics Data System (ADS)

    Su, Yingna; Li, Shangwei; Zhou, Tuanhui; Ji, Haisheng

    2016-05-01

    We investigate the sympathetic eruptions of two solar filaments side by side as observed by the New Vacuum Solar Telescope (NVST) on 2015 October 15. These two filaments start from the complex active region NOAA 12434 (north) and end in a large quiescent region (south). The corresponding SDO/HMI magnetic field observations suggest that the two small filaments are located above two different polarity inversion lines in the northern part. The SDO/AIA observations of the eruption show that these two filaments appear to merge into one in the southern quiescent region. The north-eastern filament starts eruption firstly, which is followed by the north-western filament eruption about 20 minutes later. Clear untwisting motions (i.e., signature of flux ropes) are observed in both filaments during the eruption. After the lifts off of the north-western filament, mini filaments are observed to emerge from the surface and rise up multiple times. The high-resolution observations reveal the fact that the filament is composed of multiple sections and multiple layers. The filament in the lower layer can merge into the upper layer, which leads to the increase of non-potentiality of the upper layer. Magnetic field models using the flux rope insertion method are also constructed in order to understand the complex magnetic configuration as well as the initiation and dynamics of the eruptions.

  10. High resolution atomic force microscopy of double-stranded RNA.

    PubMed

    Ares, Pablo; Fuentes-Perez, Maria Eugenia; Herrero-Galán, Elías; Valpuesta, José M; Gil, Adriana; Gomez-Herrero, Julio; Moreno-Herrero, Fernando

    2016-06-01

    Double-stranded (ds) RNA mediates the suppression of specific gene expression, it is the genetic material of a number of viruses, and a key activator of the innate immune response against viral infections. The ever increasing list of roles played by dsRNA in the cell and its potential biotechnological applications over the last decade has raised an interest for the characterization of its mechanical properties and structure, and that includes approaches using Atomic Force Microscopy (AFM) and other single-molecule techniques. Recent reports have resolved the structure of dsDNA with AFM at unprecedented resolution. However, an equivalent study with dsRNA is still lacking. Here, we have visualized the double helix of dsRNA under near-physiological conditions and at sufficient resolution to resolve the A-form sub-helical pitch periodicity. We have employed different high-sensitive force-detection methods and obtained images with similar spatial resolution. Therefore, we show here that the limiting factors for high-resolution AFM imaging of soft materials in liquid medium are, rather than the imaging mode, the force between the tip and the sample and the sharpness of the tip apex. PMID:26876486

  11. High resolution photoelectron spectroscopy of clusters of Group V elements

    SciTech Connect

    Wang, Lai-sheng; Niu, B.; Lee, Y.T.; Shirley, D.A.

    1989-07-01

    High resolution HeI (580{angstrom}) photoelectron spectra of As{sub 2}, As{sub 4}, and P{sub 4} were obtained with a newly-built high temperature molecular beam source. Vibrational structure was resolved in the photoelectron spectra of the three cluster species. The Jahn-Teller effect is discussed for the {sup 2}E and {sup 2}T{sub 2} states of P{sub 4}{sup +} and As{sub 4}{sup +}. As a result of the Jahn-Teller effect, the {sup 2}E state splits into two bands, and the {sup 2}T{sub 2} state splits into three bands, in combination with the spin-orbit effect. It was observed that the {nu}{sub 2} normal vibrational mode was involved in the vibronic interaction of the {sup 2}E state, while both the {nu}{sub 2} and {nu}{sub 3} modes were active in the {sup 2}T{sub 2} state. 26 refs., 5 figs., 3 tabs.

  12. Quantification of upland thermokarst features with high resolution remote sensing

    NASA Astrophysics Data System (ADS)

    Belshe, E. F.; Schuur, E. A. G.; Grosse, G.

    2013-09-01

    Climate-induced changes to permafrost are altering high latitude landscapes in ways that could increase the vulnerability of the vast soil carbon pools of the region. Permafrost thaw is temporally dynamic and spatially heterogeneous because, in addition to the thickening of the active layer, localized thermokarst features form when ice-rich permafrost thaws and the ground subsides. Thermokarst produces a diversity of landforms and alters the physical environment in dynamic ways. To estimate potential changes to the carbon cycle it is imperative to quantify the size and distribution of thermokarst landforms. By performing a supervised classification on a high resolution IKONOS image, we detected and mapped small, irregular thermokarst features occurring within an upland watershed in discontinuous permafrost of Interior Alaska. We found that 12% of the Eight Mile Lake (EML) watershed has undergone thermokarst, predominantly in valleys where tussock tundra resides. About 35% of the 3.7 km2 tussock tundra class has likely transitioned to thermokarst. These landscape level changes created by permafrost thaw at EML have important implications for ecosystem carbon cycling because thermokarst features are forming in carbon-rich areas and are altering the hydrology in ways that increase seasonal thawing of the soil.

  13. Global High Resolution Mapping and Assimilation of Soil Moisture Observations for the SMAP Radar and Radiometer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active and Passive (SMAP) mission is being developed by NASA for launch in 2015. The primary science objectives of SMAP are to enhance understanding of land surface controls on the water, energy and carbon cycles, and to determine their linkages. Moreover, SMAP high-resolution so...

  14. Io from High-Resolution Galileo PPR Data Taken Simultaneously with SSI or NIMS Observations

    NASA Astrophysics Data System (ADS)

    Rathbun, J. A.; Block, M. G.; Spencer, J. R.

    2005-03-01

    Io is the most volcanically active body in the solar system. Here, we present high-resolution Galileo PPR data taken simultaneously with NIMS and SSI. The data are used to examine volcano temperatures at Emakong, Pele, Zamama, Amirani, and other locations.

  15. High-resolution microscopy of active ribosomal genes and key members of the rRNA processing machinery inside nucleolus-like bodies of fully-grown mouse oocytes.

    PubMed

    Shishova, Kseniya V; Khodarovich, Yuriy M; Lavrentyeva, Elena A; Zatsepina, Olga V

    2015-10-01

    Nucleolus-like bodies (NLBs) of fully-grown (germinal vesicle, GV) mammalian oocytes are traditionally considered as morphologically distinct entities, which, unlike normal nucleoli, contain transcribed ribosomal genes (rDNA) solely at their surface. In the current study, we for the first time showed that active ribosomal genes are present not only on the surface but also inside NLBs of the NSN-type oocytes. The "internal" rRNA synthesis was evidenced by cytoplasmic microinjections of BrUTP as precursor and by fluorescence in situ hybridization with a probe to the short-lived 5'ETS segment of the 47S pre-rRNA. We further showed that in the NLB mass of NSN-oocytes, distribution of active rDNA, RNA polymerase I (UBF) and rRNA processing (fibrillarin) protein factors, U3 snoRNA, pre-rRNAs and 18S/28S rRNAs is remarkably similar to that in somatic nucleoli capable to make pre-ribosomes. Overall, these observations support the occurrence of rDNA transcription, rRNA processing and pre-ribosome assembly in the NSN-type NLBs and so that their functional similarity to normal nucleoli. Unlike the NSN-type NLBs, the NLBs of more mature SN-oocytes do not contain transcribed rRNA genes, U3 snoRNA, pre-rRNAs, 18S and 28S rRNAs. These results favor the idea that in a process of transformation of NSN-oocytes to SN-oocytes, NLBs cease to produce pre-ribosomes and, moreover, lose their rRNAs. We also concluded that a denaturing fixative 70% ethanol used in the study to fix oocytes could be more appropriate for light microscopy analysis of nucleolar RNAs and proteins in mammalian fully-grown oocytes than a commonly used cross-linking aldehyde fixative, formalin. PMID:26226217

  16. A Fluorescein Tracer Release Experiment in the Hydrothermally Active Crater of Vailulu'u Volcano, Samoa

    NASA Astrophysics Data System (ADS)

    Hart, S. R.; Staudigel, H.; Workman, R.; Koppers, A.; Girard, A.

    2001-12-01

    Vailulu'u (Rockne) volcano marks the active end of the Samoa hotspot chain. The volcano is 4400 meters high, with a summit crater 2000 meters wide by 400 meters deep and summit peaks reaching to within 600 meters of the sea surface. The crater is hydrothermally active, as witnessed by intense particulate concentrations in the water column (values to 1.4 NTU's), a particulate smog ``halo'' surrounding the summit and extending out many kilometers, high Mn concentrations and 3He/4He ratios (values to 3.8 ppb and 8.6 Ra, respectively), and bottom-water temperature anomalies of 0.5oC. Basalts from the crater have been dated in the range 5-50 years, and likely reflect eruptions associated with a 1995 earthquake swarm. On April 3, 2001, we released a 20 kg point-source charge of fluorescein dye 30 meters above the 975m deep crater floor. The dye was dissolved in a 180 liter mixture of propanol and water, adjusted to a density 1.3 per mil heavier than the ambient water at the release depth. Released from a rubberized bag by means of a galvanic link. First detection of the released dye was 39 hours after the deployment; the dye was in a 50 meter thick layer, with a concentration peak at 900 meters (relative to the release depth of 945m). Tracking was carried out by a CTD-based fluorometer operated in tow-yo mode from the U.S.C.G. Icebreaker Polar Sea. The detection limit was 25 picograms/gram, and the maximum detected concentration was 18,000 pg/g (if evenly dispersed in the lower 150 meters of water in the crater, the expected concentration would be approx. 130 pg/g). While the dye pool was only surveyed for 4 days due to ship-transit constraints, significant horizontal and vertical dispersion was apparent. Vertical dispersion velocities were typically 0.05 cm/sec; horizontal velocities were typically higher by a factor of 10. An approximate diapycnal or eddy diffusivity, K, can be calculated from the rate of vertical spreading of the dye layer: K = Z2/2(t-t0), where Z is

  17. A method for generating high resolution satellite image time series

    NASA Astrophysics Data System (ADS)

    Guo, Tao

    2014-10-01

    There is an increasing demand for satellite remote sensing data with both high spatial and temporal resolution in many applications. But it still is a challenge to simultaneously improve spatial resolution and temporal frequency due to the technical limits of current satellite observation systems. To this end, much R&D efforts have been ongoing for years and lead to some successes roughly in two aspects, one includes super resolution, pan-sharpen etc. methods which can effectively enhance the spatial resolution and generate good visual effects, but hardly preserve spectral signatures and result in inadequate analytical value, on the other hand, time interpolation is a straight forward method to increase temporal frequency, however it increase little informative contents in fact. In this paper we presented a novel method to simulate high resolution time series data by combing low resolution time series data and a very small number of high resolution data only. Our method starts with a pair of high and low resolution data set, and then a spatial registration is done by introducing LDA model to map high and low resolution pixels correspondingly. Afterwards, temporal change information is captured through a comparison of low resolution time series data, and then projected onto the high resolution data plane and assigned to each high resolution pixel according to the predefined temporal change patterns of each type of ground objects. Finally the simulated high resolution data is generated. A preliminary experiment shows that our method can simulate a high resolution data with a reasonable accuracy. The contribution of our method is to enable timely monitoring of temporal changes through analysis of time sequence of low resolution images only, and usage of costly high resolution data can be reduces as much as possible, and it presents a highly effective way to build up an economically operational monitoring solution for agriculture, forest, land use investigation

  18. 235U, 238U, 232Th, 40K and 137Cs activity concentrations in marine sediments along the northern coast of Oman Sea using high-resolution gamma-ray spectrometry.

    PubMed

    Zare, Mohammad Reza; Mostajaboddavati, Mojtaba; Kamali, Mahdi; Abdi, Mohammad Reza; Mortazavi, Mohammad Seddigh

    2012-09-01

    The natural radioactivity levels in sediment samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz canyon to Goatr seaport, as the first time has been determined. The results of measurements will serve as background reference level for Oman Sea coastlines. Sediments from 36 coastal and near shore locations were collected for analysis. Analysis on the collected samples were carried out to determine (235)U, (238)U, (232)Th, (40)K and (137)Cs using two high purity germanium detectors with 38.5% and 55% relative efficiencies. The concentration of (235)U, (238)U, (232)Th, (40)K and (137)Cs in sediment samples ranged between 1.01 and 2.87 Bq/kg, 11.83 and 22.68 Bq/kg, 10.7 and 25.02 Bq/kg, 222.89 and 535.07 Bq/kg and 0.14 and 2.8 Bq/kg, respectively. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. PMID:22717321

  19. High-resolution mantle tomography of China and surrounding regions

    NASA Astrophysics Data System (ADS)

    Huang, Jinli; Zhao, Dapeng

    2006-09-01

    A high-resolution P wave tomographic model of the crust and mantle down to 1100 km depth under China and surrounding regions is determined by using about one million arrival times of P, pP, PP, and PcP waves from 19,361 earthquakes recorded by 1012 seismic stations. The subducting Pacific slab is imaged clearly as a high-velocity zone from the oceanic trenches down to about 600 km depth, and intermediate-depth and deep earthquakes are located within the slab. The Pacific slab becomes stagnant in the mantle transition zone under east China. The western edge of the stagnant slab is roughly coincident with a surface topographic boundary in east China. The active Changbai and Wudalianchi intraplate volcanoes in northeast China are underlain by significant slow anomalies in the upper mantle, above the stagnant Pacific slab. These results suggest that the active intraplate volcanoes in NE China are not hot spots but a kind of back-arc volcano associated with the deep subduction of the Pacific slab and its stagnancy in the transition zone. Under the Mariana arc, however, the Pacific slab penetrates directly down to the lower mantle. The active Tengchong volcano in southwest China is related to the eastward subduction of the Burma microplate. The subducting Indian and Philippine Sea plates are also imaged clearly. The Indian plate has subducted down to 200-300 km depth under the Tibetan Plateau with a horizontal moving distance of about 500 km. High-velocity anomalies are revealed in the upper mantle under the Tarim basin, Ordos, and Sichuan basin, which are three stable blocks in China.

  20. A survey of HC3N in extragalactic sources. Is HC3N a tracer of activity in ULIRGs?

    NASA Astrophysics Data System (ADS)

    Lindberg, J. E.; Aalto, S.; Costagliola, F.; Pérez-Beaupuits, J.-P.; Monje, R.; Muller, S.

    2011-03-01

    Context. HC3N is a molecule that is mainly associated with Galactic star-forming regions, but it has also been detected in extragalactic environments. Aims: To present the first extragalactic survey of HC3N, when combining earlier data from the literature with six new single-dish detections, and to compare HC3N with other molecular tracers (HCN, HNC), as well as other properties (silicate absorption strength, IR flux density ratios, C ii flux, and megamaser activity). Methods: We present mm IRAM 30 m, OSO 20 m, and SEST observations of HC3N rotational lines (mainly the J = 10-9 transition) and of the J = 1-0 transitions of HCN and HNC. Our combined HC3N data account for 13 galaxies (excluding the upper limits reported for the non-detections), while we have HCN and HNC data for more than 20 galaxies. Results: A preliminary definition "HC3N-luminous galaxy" is made based upon the HC3N/HCN ratio. Most (~80%) HC3N-luminous galaxies seem to be deeply obscured galaxies and (U)LIRGs. A majority (~60% or more) of the HC3N-luminous galaxies in the sample present OH mega- or strong kilomaser activity. A possible explanation is that both HC3N and OH megamasers need warm dust for their excitation. Alternatively, the dust that excites the OH megamaser offers protection against UV destruction of HC3N. A high silicate absorption strength is also found in several of the HC3N-luminous objects, which may help the HC3N to survive. Finally, we find that a high HC3N/HCN ratio is related to a high dust temperature and a low C ii flux. Appendix is only available in electronic form at http://www.aanda.org

  1. Offset active galactic nuclei as tracers of galaxy mergers and supermassive black hole growth

    SciTech Connect

    Comerford, Julia M.; Greene, Jenny E.

    2014-07-10

    Offset active galactic nuclei (AGNs) are AGNs that are in ongoing galaxy mergers, which produce kinematic offsets in the AGNs relative to their host galaxies. Offset AGNs are also close relatives of dual AGNs. We conduct a systematic search for offset AGNs in the Sloan Digital Sky Survey by selecting AGN emission lines that exhibit statistically significant line-of-sight velocity offsets relative to systemic. From a parent sample of 18,314 Type 2 AGNs at z < 0.21, we identify 351 offset AGN candidates with velocity offsets of 50 km s{sup –1} < |Δv| < 410 km s{sup –1}. When we account for projection effects in the observed velocities, we estimate that 4%-8% of AGNs are offset AGNs. We designed our selection criteria to bypass velocity offsets produced by rotating gas disks, AGN outflows, and gravitational recoil of supermassive black holes, but follow-up observations are still required to confirm our candidates as offset AGNs. We find that the fraction of AGNs that are offset candidates increases with AGN bolometric luminosity, from 0.7% to 6% over the luminosity range 43 < log (L{sub bol}) [erg s{sup –1}] <46. If these candidates are shown to be bona fide offset AGNs, then this would be direct observational evidence that galaxy mergers preferentially trigger high-luminosity AGNs. Finally, we find that the fraction of AGNs that are offset AGN candidates increases from 1.9% at z = 0.1 to 32% at z = 0.7, in step with the growth in the galaxy merger fraction over the same redshift range.

  2. Subglacial bedrock topography of an active mountain glacier in a high Alpine setting - insights from high resolution 3D cosmic-muon radiography of the Eiger glacier (Bern, Central Alps, Switzerland)

    NASA Astrophysics Data System (ADS)

    Mair, David; Lechmann, Alessandro; Nishiyama, Ryuichi; Schlunegger, Fritz; Ariga, Akitaka; Ariga, Tomoko; Scampoli, Paola; Vladymyrov, Mykhailo; Ereditato, Antonio

    2016-04-01

    Bedrock topography and therefore the spatial-altitudinal distribution of ice thickness constrain the ice flow as well as the erosional mechanisms of glaciers. Although the processes by which glaciers have shaped modern and past landscapes have been well investigated, little information is still available about the shape of the bedrock beneath active glaciers in steep Alpine cirques. Here, we we apply the cosmic-muon radiography technology, which uses nuclear emulsion detectors for imaging the bedrock surface. This method should provide information on the bedrock topography beneath a glacier and related ice thicknesses and subglacial meltwater pathways. We apply this technology to the cirque of the Eiger glacier, situated on the western flank of Eiger mountain, Central Swiss Alps. The Eiger glacier originates on the western flank of the Eiger at 3700 m a.s.l., from where it stretches along 2.6 km to the current elevation at 2300 m a.s.l.. The glacier consists of a concave cirque bordered by >40° steep flanks, thereby utilizing weaknesses within the fabric of the bedrock such as folds, joints and foliations. The middle reach hosts a bedrock ridge where glacier diffluence occurs. The lower reaches of the glacier are characterized by several transverse crevasses, while the terminal lobe hosts multiple longitudinal crevasses. A basal till and lateral margins border the ice flow along the lowermost reach. While subglacial erosion in the cirque has probably been accomplished by plucking and abrasion where the glacier might be cold-based, sub glacial melt water might have contributed to bedrock sculpting farther downslope where the ice flow is constrained by bedrock. Overdeepening of some tens of meters is expected in the upper reach of the glacier, which is quite common in cirques (Cook & Swift, 2012). Contrariwise, we expect several tens of meters-deep bedrock excavations (characterized by concave curvatures of bedrock surface) at the site of ice diffluence. The next

  3. High-resolution spectroscopy of jet-cooled CH{sub 5}{sup +}: Progress

    SciTech Connect

    Savage, C.; Dong, F.; Nesbitt, D. J.

    2015-01-22

    Protonated methane (CH{sub 5}{sup +}) is thought to be a highly abundant molecular ion in interstellar medium, as well as a potentially bright μwave- mm wave emitter that could serve as a tracer for methane. This paper describes progress and first successful efforts to obtain a high resolution, supersonically cooled spectrum of CH{sub 5}{sup +} in the 2900-3100 cm{sup −1} region, formed in a slit supersonic discharge at low jet temperatures and with sub-Doppler resolution. Short term precision in frequency measurement (< 5 MHz on an hour time scale) is obtained from a thermally controlled optical transfer cavity servoloop locked onto a frequency stabilized HeNe laser. Long term precision (< 20 MHz day-to-day) due to pressure, temperature and humidity dependent index of refraction effects in the optical transfer cavity is also present and discussed.

  4. High Resolution Observations and Modeling of Small-Scale Solar Magnetic Elements

    NASA Technical Reports Server (NTRS)

    Berger, Thomas E.

    2001-01-01

    This research contract investigating the radiative transfer and dynamic physics of the smallest observable magnetic structures in the solar photosphere. Due to the lack of a high-resolution visible light satellite instrument for solar studies, all data were acquired using ground-based instrumentation. The primary goal of the investigation was to understand the formation and evolution of "G-band bright points" in relation to the associated magnetic elements. G-band bright points are small (on the order of 100 kin or less in diameter) bright signatures associated with magnetic flux elements in the photosphere. They are seen in the A2A-X2 4308 A molecular bandhead of the CH radical ill the solar spectrum and offer the highest spatial resolution and highest contrast "tracers" of small magnetic structure on the Sun.

  5. Design of POSICAM: A high resolution multislice whole body positron camera

    SciTech Connect

    Mullani, N.A.; Wong, W.H.; Hartz, R.K.; Bristow, D.; Gaeta, J.M.; Yerian, K.; Adler, S.; Gould, K.L.

    1985-01-01

    A high resolution (6mm), multislice (21) whole body positron camera has been designed with innovative detector and septa arrangement for 3-D imaging and tracer quantitation. An object of interest such as the brain and the heart is optimally imaged by the 21 simultaneous image planes which have 12 mm resolution and are separated by 5.5 mm to provide adequate sampling in the axial direction. The detector geometry and the electronics are flexible enough to allow BaF/sub 2/, BGO, GSO or time of flight BaF/sub 2/ scintillators. The mechanical gantry has been designed for clinical applications and incorporates several features for patient handling and comfort. A large patient opening of 58 cm diameter with a tilt of +-30/sup 0/ and rotation of +-20/sup 0/ permit imaging from different positions without moving the patient. Multiprocessor computing systems and user-friendly software make the POSICAM a powerful 3-D imaging device. 7 figs.

  6. High Resolution Local Structure-Constrained Image Upsampling.

    PubMed

    Zhao, Yang; Wang, Ronggang; Wang, Wenmin; Gao, Wen

    2015-11-01

    With the development of ultra-high-resolution display devices, the visual perception of fine texture details is becoming more and more important. A method of high-quality image upsampling with a low cost is greatly needed. In this paper, we propose a fast and efficient image upsampling method that makes use of high-resolution local structure constraints. The average local difference is used to divide a bicubic-interpolated image into a sharp edge area and a texture area, and these two areas are reconstructed separately with specific constraints. For reconstruction of the sharp edge area, a high-resolution gradient map is estimated as an extra constraint for the recovery of sharp and natural edges; for the reconstruction of the texture area, a high-resolution local texture structure map is estimated as an extra constraint to recover fine texture details. These two reconstructed areas are then combined to obtain the final high-resolution image. The experimental results demonstrated that the proposed method recovered finer pixel-level texture details and obtained top-level objective performance with a low time cost compared with state-of-the-art methods. PMID:26186777

  7. Design and implementation of spaceborne high resolution infrared touch screen

    NASA Astrophysics Data System (ADS)

    Li, Tai-guo; Li, Wen-xin; Dong, Yi-peng; Ma, Wen; Xia, Jia-gao

    2015-10-01

    For the consideration of the special application environment of the electronic products used in aerospace and to further more improve the human-computer interaction of the manned aerospace area. The research is based on the design and implementation way of the high resolution spaceborne infrared touch screen on the basis of FPGA and DSP frame structure. Beside the introduction of the whole structure for the high resolution spaceborne infrared touch screen system, this essay also gives the detail information about design of hardware for the high resolution spaceborne infrared touch screen system, FPGA design, GUI design and DSP algorithm design based on Lagrange interpolation. What is more, the easy makes a comprehensive research of the reliability design for the high resolution spaceborne infrared touch screen for the special purpose of it. Besides, the system test is done after installation of spaceborne infrared touch screen. The test result shows that the system is simple and reliable enough, which has a stable running environment and high resolution, which certainly can meet the special requirement of the manned aerospace instrument products.

  8. Clickstream Data Yields High-Resolution Maps of Science

    PubMed Central

    Bollen, Johan; Van de Sompel, Herbert; Rodriguez, Marko A.; Balakireva, Lyudmila

    2009-01-01

    Background Intricate maps of science have been created from citation data to visualize the structure of scientific activity. However, most scientific publications are now accessed online. Scholarly web portals record detailed log data at a scale that exceeds the number of all existing citations combined. Such log data is recorded immediately upon publication and keeps track of the sequences of user requests (clickstreams) that are issued by a variety of users across many different domains. Given these advantages of log datasets over citation data, we investigate whether they can produce high-resolution, more current maps of science. Methodology Over the course of 2007 and 2008, we collected nearly 1 billion user interactions recorded by the scholarly web portals of some of the most significant publishers, aggregators and institutional consortia. The resulting reference data set covers a significant part of world-wide use of scholarly web portals in 2006, and provides a balanced coverage of the humanities, social sciences, and natural sciences. A journal clickstream model, i.e. a first-order Markov chain, was extracted from the sequences of user interactions in the logs. The clickstream model was validated by comparing it to the Getty Research Institute's Architecture and Art Thesaurus. The resulting model was visualized as a journal network that outlines the relationships between various scientific domains and clarifies the connection of the social sciences and humanities to the natural sciences. Conclusions Maps of science resulting from large-scale clickstream data provide a detailed, contemporary view of scientific activity and correct the underrepresentation of the social sciences and humanities that is commonly found in citation data. PMID:19277205

  9. High resolution single particle refinement in EMAN2.1.

    PubMed

    Bell, James M; Chen, Muyuan; Baldwin, Philip R; Ludtke, Steven J

    2016-05-01

    EMAN2.1 is a complete image processing suite for quantitative analysis of grayscale images, with a primary focus on transmission electron microscopy, with complete workflows for performing high resolution single particle reconstruction, 2-D and 3-D heterogeneity analysis, random conical tilt reconstruction and subtomogram averaging, among other tasks. In this manuscript we provide the first detailed description of the high resolution single particle analysis pipeline and the philosophy behind its approach to the reconstruction problem. High resolution refinement is a fully automated process, and involves an advanced set of heuristics to select optimal algorithms for each specific refinement task. A gold standard FSC is produced automatically as part of refinement, providing a robust resolution estimate for the final map, and this is used to optimally filter the final CTF phase and amplitude corrected structure. Additional methods are in-place to reduce model bias during refinement, and to permit cross-validation using other computational methods. PMID:26931650

  10. Single sensor processing to obtain high resolution color component signals

    NASA Technical Reports Server (NTRS)

    Glenn, William E. (Inventor)

    2010-01-01

    A method for generating color video signals representative of color images of a scene includes the following steps: focusing light from the scene on an electronic image sensor via a filter having a tri-color filter pattern; producing, from outputs of the sensor, first and second relatively low resolution luminance signals; producing, from outputs of the sensor, a relatively high resolution luminance signal; producing, from a ratio of the relatively high resolution luminance signal to the first relatively low resolution luminance signal, a high band luminance component signal; producing, from outputs of the sensor, relatively low resolution color component signals; and combining each of the relatively low resolution color component signals with the high band luminance component signal to obtain relatively high resolution color component signals.

  11. A high-resolution vehicle emission inventory for China

    NASA Astrophysics Data System (ADS)

    Zheng, B.; Zhang, Q.; He, K.; Huo, H.; Yao, Z.; Wang, X.

    2012-12-01

    Developing high resolution emission inventory is an essential task for air quality modeling and management. However, current vehicle emission inventories in China are usually developed at provincial level and then allocated to grids based on various spatial surrogates, which is difficult to get high spatial resolution. In this work, we developed a new approach to construct a high-resolution vehicle emission inventory for China. First, vehicle population at county level were estimated by using the relationship between per-capita GDP and vehicle ownership. Then the Weather Research and Forecasting (WRF) model were used to drive the International Vehicle Emission (IVE) model to get monthly emission factors for each county. Finally, vehicle emissions by county were allocated to grids with 5-km horizon resolution by using high-resolution road network data. This work provides a better understanding of spatial representation of vehicle emissions in China and can benefit both air quality modeling and management with improved spatial accuracy.

  12. High-resolution signal synthesis for time-frequency distributions

    SciTech Connect

    Cunningham, G.S.; Williams, W.J.

    1993-03-01

    Bilinear time-frequency distributions (TFDs) offer improved resolution over linear nine-frequency representations (TFRs), but many TFDs are costly to evaluate and are not associated with signal synthesis algorithms. Recently, the spectrogram (SP) decomposition and weighted reversal correlator decomposition have been used to define low-cost, high-resolution TFDs. In this paper, we show that the vector-valued ``square-root`` of a TFD (VVTFR) provides a representational underpinning for the TFD. By synthesizing signals from modified VVTFRs, we define high-resolution signal synthesis algorithms associated with TFDs. The signal analysis and synthesis packages can be implemented as weighted sums of SP/short-time Fourier Transform signal analysis and synthesis packages, which are widely available, allowing the interested non-specialist easy access to high-resolution methods.

  13. High-resolution signal synthesis for time-frequency distributions

    SciTech Connect

    Cunningham, G.S. ); Williams, W.J. . Dept. of Electrical Engineering and Computer Science)

    1993-01-01

    Bilinear time-frequency distributions (TFDs) offer improved resolution over linear nine-frequency representations (TFRs), but many TFDs are costly to evaluate and are not associated with signal synthesis algorithms. Recently, the spectrogram (SP) decomposition and weighted reversal correlator decomposition have been used to define low-cost, high-resolution TFDs. In this paper, we show that the vector-valued square-root'' of a TFD (VVTFR) provides a representational underpinning for the TFD. By synthesizing signals from modified VVTFRs, we define high-resolution signal synthesis algorithms associated with TFDs. The signal analysis and synthesis packages can be implemented as weighted sums of SP/short-time Fourier Transform signal analysis and synthesis packages, which are widely available, allowing the interested non-specialist easy access to high-resolution methods.

  14. New vacuum solar telescope and observations with high resolution

    NASA Astrophysics Data System (ADS)

    Liu, Zhong; Xu, Jun; Gu, Bo-Zhong; Wang, Sen; You, Jian-Qi; Shen, Long-Xiang; Lu, Ru-Wei; Jin, Zhen-Yu; Chen, Lin-Fei; Lou, Ke; Li, Zhi; Liu, Guang-Qian; Xu, Zhi; Rao, Chang-Hui; Hu, Qi-Qian; Li, Ru-Feng; Fu, Hao-Wen; Wang, Feng; Bao, Men-Xian; Wu, Ming-Chan; Zhang, Bo-Rong

    2014-06-01

    The New Vacuum Solar Telescope (NVST) is a one meter vacuum solar telescope that aims to observe fine structures on the Sun. The main goals of NVST are high resolution imaging and spectral observations, including measurements of the solar magnetic field. NVST is the primary ground-based facility used by the Chinese solar research community in this solar cycle. It is located by Fuxian Lake in southwest China, where the seeing is good enough to perform high resolution observations. We first introduce the general conditions at the Fuxian Solar Observatory and the primary science cases of NVST. Then, the basic structures of this telescope and instruments are described in detail. Finally, some typical high resolution data of the solar photosphere and chromosphere are also shown.

  15. High-resolution Urban Image Classification Using Extended Features

    SciTech Connect

    Vatsavai, Raju

    2011-01-01

    High-resolution image classification poses several challenges because the typical object size is much larger than the pixel resolution. Any given pixel (spectral features at that location) by itself is not a good indicator of the object it belongs to without looking at the broader spatial footprint. Therefore most modern machine learning approaches that are based on per-pixel spectral features are not very effective in high- resolution urban image classification. One way to overcome this problem is to extract features that exploit spatial contextual information. In this study, we evaluated several features in- cluding edge density, texture, and morphology. Several machine learning schemes were tested on the features extracted from a very high-resolution remote sensing image and results were presented.

  16. Estimation of high-resolution dust column density maps. Empirical model fits

    NASA Astrophysics Data System (ADS)

    Juvela, M.; Montillaud, J.

    2013-09-01

    Context. Sub-millimetre dust emission is an important tracer of column density N of dense interstellar clouds. One has to combine surface brightness information at different spatial resolutions, and specific methods are needed to derive N at a resolution higher than the lowest resolution of the observations. Some methods have been discussed in the literature, including a method (in the following, method B) that constructs the N estimate in stages, where the smallest spatial scales being derived only use the shortest wavelength maps. Aims: We propose simple model fitting as a flexible way to estimate high-resolution column density maps. Our goal is to evaluate the accuracy of this procedure and to determine whether it is a viable alternative for making these maps. Methods: The new method consists of model maps of column density (or intensity at a reference wavelength) and colour temperature. The model is fitted using Markov chain Monte Carlo methods, comparing model predictions with observations at their native resolution. We analyse simulated surface brightness maps and compare its accuracy with method B and the results that would be obtained using high-resolution observations without noise. Results: The new method is able to produce reliable column density estimates at a resolution significantly higher than the lowest resolution of the input maps. Compared to method B, it is relatively resilient against the effects of noise. The method is computationally more demanding, but is feasible even in the analysis of large Herschel maps. Conclusions: The proposed empirical modelling method E is demonstrated to be a good alternative for calculating high-resolution column density maps, even with considerable super-resolution. Both methods E and B include the potential for further improvements, e.g., in the form of better a priori constraints.

  17. High resolution neodymium characterization along the Mediterranean Sea margins: implications for ɛNd modeling.

    NASA Astrophysics Data System (ADS)

    Ayache, Mohamed; Dutay, Jean-claude; Arsouze, Thomas; Jeandel, Catherine; Revillon, Sidonie

    2016-04-01

    An extensive compilation of published neodymium (Nd) concentrations and isotopic compositions (ɛNd) was realized in order to establish a new database and a map (using a high resolution geological map of the area) of the distribution of these parameters for all the Mediterranean margins. Data were extracted from different kinds of samples: river solid discharge deposited on the shelf, sedimentary material collected on the margin or geological material outcropping above or close to a margin. Additional analyses of surface sediments were done, in order to improve this dataset in key areas (e.g Sicilian strait). The Mediterranean margin Nd isotopic signatures vary from non-radiogenic values around the Gulf of Lions, (ɛNd values -11) to radiogenic values around the Aegean and the Levantine sub-basins up to +6. Using a high resolution regional oceanic model (1/12° of horizontal resolution), ɛNd distribution was simulated for the first time in the Mediterranean Sea. The high resolution of the model provides the opportunity to study in more details the processes governing the Nd isotope distribution in the marine environment. This work highlights that a significant interannual variability of ɛNd distribution in seawater could occur. In particular, important hydrological events such as the Eastern Mediterranean Transient (EMT), associated with deep water formed in the Aegean sub-basin, could induce a shift in Nd IC at intermediate depths that could be noticeable in the Western part of the basin. This highlights that the temporal and geographical variations of ɛNd could represent an interesting insight of Nd as a quasi-conservative tracer of water masses in the Mediterranean Sea, in particular in the context of paleo-oceanographic applications, i.e. to explore if EMT-type signatures occurred in the past (Roether et al., 2014, Gacic et al., 2011).

  18. High resolution squid magnetometry for non-destructive evaluation. Final report, 1 September 1987-30 April 1993

    SciTech Connect

    Wikswo, J.P.

    1993-04-30

    Superconducting QUantum Interference Device (SQUID) magnetometers offer promise as multi-mode instruments capable of obtaining high resolution images of extremely low frequency injected currents or eddy currents, and they can be configured to image the magnetic susceptibility of titanium, aluminum and nonmetallic composites. While high resolution SQUID magnetometers will generally be noisier than conventional SQUIDs, the small coils and reduced coil-to-source spacing more than compensate to provide low-noise, high-resolution images. The high spatial resolution which can be obtained with SQUID magnetometers, the unparalleled sensitivity of SQUIDs at low frequencies, the ability to measure weak perturbations in strong applied magnetic fields, and the ability to discriminate against external sources of noise should make SQUID magnetometers well suited for NDE of deep flaws in aluminum and titanium aerostructures. To explore SQUID NDE, the authors have developed research facilities that include the high-resolution MicroSQUID magnetometer, a magnetic shield, a scanning stage, and a computer-based control and data acquisition system. Using this instrumentation, they have imaged magnetic fields produced by sources as varied as intrinsic currents due to corrosion or Johnson noise, remanent magnetization from ferromagnetic contamination, flaw-induced perturbations in either injected current or eddy currents induced by an AC field, Johnson noise currents in a copper ring, persistent currents in high transition-temperature superconductors, distributions of dia- or paramagnetism in an AC or DC magnetic field, and surface flaws decorated with a paramagnetic tracer.

  19. HIRES: the high resolution spectrograph for the E-ELT

    NASA Astrophysics Data System (ADS)

    Zerbi, F. M.; Bouchy, F.; Fynbo, J.; Maiolino, R.; Piskunov, N.; Rebolo Lopez, R.; Santos, N.; Strassmeier, K.; Udry, S.; Vanzi, L.; Riva, M.; Basden, A.; Boisse, I.; Bonfils, X.; Buscher, D.; Cabral, A.; Dimarcantonio, P.; Di Varano, I.; Henry, D.; Monteiro, M.; Morris, T.; Murray, G.; Oliva, Ernesto; Parry, I.; Pepe, F.; Quirrenbach, A.; Rasilla, J. L.; Rees, P.; Stempels, E.; Valenziano, L.; Wells, M.; Wildi, F.; Origlia, L.; Allende Prieto, C.; Chiavassa, A.; Cristiani, S.; Figueira, P.; Gustafsson, B.; Hatzes, A.; Haehnelt, M.; Heng, K.; Israelian, G.; Kochukhov, O.; Lovis, C.; Marconi, A.; Martins, C. J. A. P.; Noterdaeme, P.; Petitjean, P.; Puzia, T.; Queloz, D.; Reiners, A.; Zoccali, M.

    2014-08-01

    The current instrumentation plan for the E-ELT foresees a High Resolution Spectrograph conventionally indicated as HIRES. Shaped on the study of extra-solar planet atmospheres, Pop-III stars and fundamental physical constants, HIRES is intended to embed observing modes at high-resolution (up to R=150000) and large spectral range (from the blue limit to the K band) useful for a large suite of science cases that can exclusively be tackled by the E-ELT. We present in this paper the solution for HIRES envisaged by the "HIRES initiative", the international collaboration established in 2013 to pursue a HIRES on E-ELT.

  20. Microbeam X-Ray Standing Wave and High Resolution Diffraction

    SciTech Connect

    Kazimirov, A.; Bilderback, D.H.; Huang, R.; Sirenko, A.

    2004-05-12

    Post-focusing collimating optics are introduced as a tool to condition X-ray microbeams for the use in high-resolution X-ray diffraction and scattering techniques. As an example, a one-bounce imaging capillary and miniature Si(004) channel-cut crystal were used to produce a microbeam with 10 {mu}m size and an ultimate angular resolution of 2.5 arc sec. This beam was used to measure the strain in semiconductor microstructures by using X-ray high resolution diffraction and standing wave techniques to {delta}d/d < 5x10-4.

  1. High resolution BPMS with integrated gain correction system

    SciTech Connect

    Wendt, M.; Briegel, C.; Eddy, N.; Fellenz, B.; Gianfelice, E.; Prieto, P.; Rechenmacher, R.; Voy, D.; Terunuma, N.; Urakawa, J.; /KEK, Tsukuba

    2009-08-01

    High resolution beam position monitors (BPM) are an essential tool to achieve and reproduce a low vertical beam emittance at the KEK Accelerator Test Facility (ATF) damping ring. The ATF damping ring (DR) BPMs are currently upgraded with new high resolution read-out electronics. Based on analog and digital down-conversion techniques, the upgrade includes an automatic gain calibration system to correct for slow drift effects and ensure high reproducible beam position readings. The concept and its technical realization, as well as preliminary results of beam studies are presented.

  2. Modified Noise Power Ratio testing of high resolution digitizers

    SciTech Connect

    McDonald, T.S.

    1994-05-01

    A broadband, full signal range, side-by-side (tandem) test method for estimating the internal noise performance of high resolution digitizers is described and illustrated. The technique involves a re-definition of the traditional Noise Power Ratio (NPR) test, a change that not only makes this test applicable to higher resolution systems than was previously practical, but also enhances its value and flexibility. Since coherence analysis is the basis of this new definition, and since the application of coherence procedures to high resolution data poses several problems, this report discusses these problems and their resolution.

  3. Theoretical Problems in High Resolution Solar Physics, 2

    NASA Technical Reports Server (NTRS)

    Athay, G. (Editor); Spicer, D. S. (Editor)

    1987-01-01

    The Science Working Group for the High Resolution Solar Observatory (HRSO) laid plans beginning in 1984 for a series of workshops designed to stimulate a broadbased input from the scientific community to the HRSO mission. These workshops have the dual objectives of encouraging an early start on the difficult theoretical problems in radiative transfer, magnetohydrodynamics, and plasma physics that will be posed by the HRSO data, and maintaining current discussions of results in high resolution solar studies. This workshop was the second in the series. The workshop format presented invited review papers during the formal sessions and contributed poster papers for discussions during open periods. Both are presented.

  4. High Resolution 3D Radar Imaging of Comet Interiors

    NASA Astrophysics Data System (ADS)

    Asphaug, E. I.; Gim, Y.; Belton, M.; Brophy, J.; Weissman, P. R.; Heggy, E.

    2012-12-01

    images of interior structure to ~20 m, and to map dielectric properties (related to internal composition) to better than 200 m throughout. This is comparable in detail to modern 3D medical ultrasound, although we emphasize that the techniques are somewhat different. An interior mass distribution is obtained through spacecraft tracking, using data acquired during the close, quiet radar orbits. This is aligned with the radar-based images of the interior, and the shape model, to contribute to the multi-dimensional 3D global view. High-resolution visible imaging provides boundary conditions and geologic context to these interior views. An infrared spectroscopy and imaging campaign upon arrival reveals the time-evolving activity of the nucleus and the structure and composition of the inner coma, and the definition of surface units. CORE is designed to obtain a total view of a comet, from the coma to the active and evolving surface to the deep interior. Its primary science goal is to obtain clear images of internal structure and dielectric composition. These will reveal how the comet was formed, what it is made of, and how it 'works'. By making global yet detailed connections from interior to exterior, this knowledge will be an important complement to the Rosetta mission, and will lay the foundation for comet nucleus sample return by revealing the areas of shallow depth to 'bedrock', and relating accessible deposits to their originating provenances within the nucleus.

  5. A new high resolution tidal model in the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Cancet, Mathilde; Andersen, Ole; Lyard, Florent; Cotton, David; Benveniste, Jérôme

    2016-04-01

    The Arctic Ocean is a challenging region for tidal modeling, because of its complex and not well-documented bathymetry, together combined with the intermittent presence of sea ice and the fact that the in situ tidal observations are scarce at such high latitudes. As a consequence, the accuracy of the global tidal models decreases by several centimeters in the Polar Regions. It has a large impact on the quality of the satellite altimeter sea surface heights in these regions (ERS1/2, Envisat, CryoSat-2, SARAL/AltiKa and the future Sentinel-3 mission), but also on the end-users' applications that need accurate tidal information. Better knowledge of the tides will improve the quality of the high latitudes altimeter sea surface heights and of all derived products, such as the altimetry-derived geostrophic currents, the mean sea surface and the mean dynamic topography. In addition, accurate tidal models are highly strategic information for ever-growing maritime and industrial activities in this region. NOVELTIS and DTU Space have recently developed a regional, high-resolution tidal atlas in the Arctic Ocean, in the framework of an extension of the CryoSat Plus for Oceans (CP4O) project funded by ESA (STSE program). In particular, this atlas benefits from the assimilation of the most complete satellite altimetry dataset ever used in this region, including the Envisat data up to 82°N and the CryoSat-2 reprocessed data between 82°N and 88°N. The combination of all these satellites gives the best possible coverage of altimetry-derived tidal constituents. Tide gauge data have also been used either for assimilation or validation. This paper presents the methodology followed to develop the model and the performances of this new regional tidal model in the Arctic Ocean.

  6. High resolution imaging of the outflow channels on Mars

    NASA Astrophysics Data System (ADS)

    Davatzes, A. K.; Gulick, V. C.

    2008-12-01

    We report observations of the outflow channels on Mars from HiRISE images in MRO's first Martian year. Several hundred images of the outflow channels on Mars have been collected to date from HiRISE, as well as coordinated images with CTX and CRISM. Depositional features, such as slackwater deposits and small bedforms that are expected to be visible at the resolution of HiRISE have not yet been observed, largely due to post-fluvial modification of the channels. Many of the channels have been subsequently covered by a thin layer of lava, ash, dust, or lineated valley fill. Although altered slightly by later aeolian modification, Ares Valles and Kasei Valles preserve much of the original fluvial erosional forms, particularly cataracts and longitudinal grooves that can be used to infer the mechanics of the flow. Cataracts, steep knickpoints in the large outflow channels, were once large waterfalls on the Martian surface. These have been observed in all of the larger outflow systems, including Kasai, Athabasca, Mangala, and Reull Valles. High resolution imaging shows that all of the cataract systems have multiple generations of erosion, with smaller subchannels within the cataract system. Based on the length of the recession and the morphological evidence most of the large channels experienced multiple flooding events or pulses. The tectonically sourced outflow channels, such as Athabasca and Mangala Valles, show sourcing at regions of complex fault geometries, specifically at fault relays. In terrestrial systems, relays tend to be regions of concentrated stress that can produce dilation manifested as high joint density, as well as point sources for hydrothermal outflow on Earth. Athabasca and Mangala Valles, sourced proximal to large volcanic centers, may have been regions of major hydrothermal activity in the past.

  7. Secondary eyewall formation in high resolution, realistic hurricane simulations

    NASA Astrophysics Data System (ADS)

    Abarca Fuente, Sergio Federico

    This dissertation explores the dynamics of secondary eyewall formation (SEF) through the analysis of high resolution (1.33 km), realistic integrations of the National Center for Atmospheric Research Advanced Hurricane Weather Research and Forecasting model. Numerical simulations of Hurricanes Katrina and Rita (2005) and Igor (2010) are analyzed. The evolution of these storms was well captured by the model and each simulation exhibited a secondary eyewall (SE): a ring of deep convection separate from the primary eyewall that develops a strong acceleration of the tangential wind. This acceleration manifests itself as an abrupt radial expansion of the tangential wind field, sometimes followed by an independent wind maximum. The convective and wind structures of the SE in the simulations are shown to be consistent with observations. The results presented suggest that unbalanced dynamic processes are fundamental in SEF. It is shown that vortical hot towers (VHTs) are the convective structures that constitute the SE. Their collective effects account for, (a) the establishment of the convective maximum, (b) the weakening of the primary eyewall through competition for inflow (that may culminate with an eyewall replacement cycle) and (c) the wind acceleration, that may or may not express itself as an independent secondary maximum in the tangential wind field. It is shown that the establishment of the VHTs that constitute the SE can be the result of different processes: (1) the release of large amounts of buoyant energy at the radius of the SE; and (2) the accumulation of potential vorticity at the stagnation radius of vortex Rossby waves. In either case, the SE is characterized by a positive potential vorticity anomaly in the lower troposphere that is further enhanced by VHT activity and the axisymmetrization of their remnants, increasing the likelihood for future convection to occur.

  8. The Goddard High Resolution Spectrograph Scientific Support Contract

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In 1988, Computer Sciences Corporation (CSC) was selected as the Goddard High Resolution Spectrograph (GHRS) Scientific Support Contractor (SSC). This was to have been a few months before the launch of NASA's first Great Observatory, the Hubble Space Telescope (HST). As one of five scientific instruments on HST, the GHRS was designed to obtain spectra in the 1050-3300 A ultraviolet wavelength region with a resolving power, lambda/Delta(lambda) , of up to 100,000 and relative photometric accuracy to 1%. It was built by Ball AeroSpace Systems Group under the guidance of the GHRS Investigation Definition Team (IDT), comprised of 16 scientists from the US and Canada. After launch, the IDT was to perform the initial instrument calibration and execute a broad scientific program during a five-year Guaranteed Time Observation (GTO) period. After a year's delay, the launch of HST occurred in April 1990, and CSC participated in the in-orbit calibration and first four years of GTO observations with the IDT. The HST primary mirror suffered from spherical aberration, which reduced the spatial and spectral resolution of Large Science Aperture (LSA) observations and decreased the throughput of the Small Science Aperture (SSA) by a factor of two. Periodic problems with the Side 1 carrousel electronics and anomalies with the low-voltage power supply finally resulted in a suspension of the use of Side 1 less than two years after launch. At the outset, the GHRS SSC task involved work in four areas: 1) to manage and operate the GHRS Data Analysis Facility (DAF); 2) to support the second Servicing Mission Observatory Verification (SMOV) program, as well as perform system engineering analysis of the GHRS as nesessary; 3) to assist the GHRS IDT with their scientific research programs, particularly the GSFC members of the team, and 4) to provide administrative and logistic support for GHRS public information and educational activities.

  9. High-resolution subsurface water-ice distributions on Mars.

    PubMed

    Bandfield, Joshua L

    2007-05-01

    Theoretical models indicate that water ice is stable in the shallow subsurface (depths of <1-2 m) of Mars at high latitudes. These models have been mainly supported by the observed presence of large concentrations of hydrogen detected by the Gamma Ray Spectrometer suite of instruments on the Mars Odyssey spacecraft. The models and measurements are consistent with a water-ice table that steadily increases in depth with decreasing latitude. More detailed modelling has predicted that the depth at which water ice is stable can be highly variable, owing to local surface heterogeneities such as rocks and slopes, and the thermal inertia of the ground cover. Measurements have, however, been limited to the footprint (several hundred kilometres) of the Gamma Ray Spectrometer suite, preventing the observations from documenting more detailed water-ice distributions. Here I show that by observing the seasonal temperature response of the martian surface with the Thermal Emission Imaging System on the Mars Odyssey spacecraft, it is possible to observe such heterogeneities at subkilometre scale. These observations show significant regional and local water-ice depth variability, and, in some cases, support distributions in the subsurface predicted by atmospheric exchange and vapour diffusion models. The presence of water ice where it follows the depth of stability under current climatic conditions implies an active martian water cycle that responds to orbit-driven climate cycles. Several regions also have apparent deviations from the theoretical stability level, indicating that additional factors influence the ice-table depth. The high-resolution measurements show that the depth to the water-ice table is highly variable within the potential Phoenix spacecraft landing ellipses, and is likely to be variable at scales that may be sampled by the spacecraft. PMID:17476262

  10. Characterizing The Nearest Young Moving Groups Through High Resolution Spectroscopy

    NASA Astrophysics Data System (ADS)

    McCarthy, Kyle; Wilhelm, Ronald J.

    2015-01-01

    We present a detailed method for characterizing the nearest young moving groups via high resolution spectroscopy. This method has three diagnostics which classify a moving group: (1) Chemical Homogeneity, (2) Kinematic Traceback, and (3) Isochrone Fitting. We have applied this technique on 10 F- and G-type stars from the AB Doradus Moving Group (ABD) and found 8 stars share similar metal abundances with an average abundance for ABD of <[M/H]> = -0.03 ± 0.06; of the two outliers, one is metal rich and the other metal poor. Seven stars follow a common traceback and share a common origin around 125 Myr. One of the outlying traceback stars diverges around 90-100 Myr, and is the same star which is metal rich. Eight stars fall along the same isochrone of 100 Myr, which is synonymous with the main sequence. We further evaluated this technique on 5 members of the newly discovered Octans-Near Moving Group (ONMG). Two of these were listed as possible members with the other three being probable members. There is a large spread in the metal abundance with <[M/H]> = -0.17 ± 0.1 and no core group of stars that define the cluster in abundance space. ONMG is also enigmatic because several age indicators (e.g. lithium abundance, surface gravities, activity) indicate a much younger cluster; however, the traceback age shows these stars were closest around 150 Myr (though this age should be taken very lightly) and 4 of the 5 stars fall on the main sequence. We therefore conclude that while these stars do share present day velocities and positions, the group is not well defined in abundance, origin, or age, and should be concidered with caution.

  11. ATS-6 - The Geosynchronous Very High Resolution Radiometer

    NASA Technical Reports Server (NTRS)

    Shenk, W. E.; Stephanides, C. C.; Sonnek, G. E.; Howell, L. D.

    1975-01-01

    The Geosynchronous Very High Resolution Radiometer (GVHRR), flown on the three-axis stabilized geosynchronous satellite, Applications Technology Satellite-6 (ATS-6), collected meteorological data for two months during the summer of 1974. Several hundred images were successfully taken. Data collection terminated when the instrument chopper motor failed. The instrument, its supporting ground equipment, and the data collected in orbit are described.

  12. Reproducible high-resolution multispectral image acquisition in dermatology

    NASA Astrophysics Data System (ADS)

    Duliu, Alexandru; Gardiazabal, José; Lasser, Tobias; Navab, Nassir

    2015-07-01

    Multispectral image acquisitions are increasingly popular in dermatology, due to their improved spectral resolution which enables better tissue discrimination. Most applications however focus on restricted regions of interest, imaging only small lesions. In this work we present and discuss an imaging framework for high-resolution multispectral imaging on large regions of interest.

  13. High resolution data base for use with MAP

    SciTech Connect

    Tapley, W.C.; Harris, D.B.

    1987-05-05

    A high resolution cartographic data base of thw World is available from the CIA. We obtained this data, extracted portions of the data, and produced cartographic files of varying resolutions. The resulting data files are of the proper format for use with MAP (2), our in-house cartographic plotting program.

  14. Ultrastable reference pulser for high-resolution spectrometers

    NASA Technical Reports Server (NTRS)

    Brenner, R.; Lenkszus, F. R.; Sifter, L. L.; Strauss, M. G.

    1970-01-01

    Solid-state double-pulse generator for a high resolution semiconductor detector meets specific requirements for resolution /0.05 percent/, amplitude range /0.1-13 MeV/, and repetition rate /0.1-1000 pulses per second/. A tag pulse is generated in coincidence with each reference pulse.

  15. High-resolution TFT-LCD for spatial light modulator

    NASA Astrophysics Data System (ADS)

    Lee, JaeWon; Kim, Yong-Hae; Byun, Chun-Won; Pi, Jae-Eun; Oh, Himchan; Kim, GiHeon; Lee, Myung-Lae; Chu, Hye-Yong; Hwang, Chi-Sun

    2014-06-01

    SLM with very fine pixel pitch is needed for the holographic display system. Among various kinds of SLMs, commercially available high resolution LCoS has been widely used as a spatial light modulator. But the size of commercially available LCoS SLM is limited because the manufacturing technology of LCoS is based on the semiconductor process developed on small size Si wafer. Recently very high resolution flat panel display panel (~500ppi) was developed as a "retina display". Until now, the pixel pitch of flat panel display is several times larger than the pixel pitch of LCoS. But considering the possibility of shrink down the pixel pitch with advanced lithographic tools, the application of flat panel display will make it possible to build a SLM with high spatial bandwidth product. We simulated High resolution TFT-LCD panel on glass substrate using oxide semiconductor TFT with pixel pitch of 20um. And we considered phase modulation behavior of LC(ECB) mode. The TFT-LCD panel is reflective type with 4-metal structure with organic planarization layers. The technical challenge for high resolution large area SLM will be discussed with very fine pixel.

  16. High-Resolution Nuclear Magnetic Resonance of Solids.

    ERIC Educational Resources Information Center

    Maciel, Gary E.

    1984-01-01

    Examines recent developments in techniques for obtaining high-resolution nuclear magnetic resonance (NMR) spectra on solid samples, discussing the kinds of applications for which these techniques are well suited. Also discusses the characteristics of NMR of solids and generating magnetization for NMR in solids. (JN)

  17. Application of Classification Models to Pharyngeal High-Resolution Manometry

    ERIC Educational Resources Information Center

    Mielens, Jason D.; Hoffman, Matthew R.; Ciucci, Michelle R.; McCulloch, Timothy M.; Jiang, Jack J.

    2012-01-01

    Purpose: The authors present 3 methods of performing pattern recognition on spatiotemporal plots produced by pharyngeal high-resolution manometry (HRM). Method: Classification models, including the artificial neural networks (ANNs) multilayer perceptron (MLP) and learning vector quantization (LVQ), as well as support vector machines (SVM), were…

  18. High resolution bone mineral densitometry with a gamma camera

    NASA Technical Reports Server (NTRS)

    Leblanc, A.; Evans, H.; Jhingran, S.; Johnson, P.

    1983-01-01

    A technique by which the regional distribution of bone mineral can be determined in bone samples from small animals is described. The technique employs an Anger camera interfaced to a medical computer. High resolution imaging is possible by producing magnified images of the bone samples. Regional densitometry of femurs from oophorectomised and bone mineral loss.

  19. Vehicle Detection and Classification from High Resolution Satellite Images

    NASA Astrophysics Data System (ADS)

    Abraham, L.; Sasikumar, M.

    2014-11-01

    In the past decades satellite imagery has been used successfully for weather forecasting, geographical and geological applications. Low resolution satellite images are sufficient for these sorts of applications. But the technological developments in the field of satellite imaging provide high resolution sensors which expands its field of application. Thus the High Resolution Satellite Imagery (HRSI) proved to be a suitable alternative to aerial photogrammetric data to provide a new data source for object detection. Since the traffic rates in developing countries are enormously increasing, vehicle detection from satellite data will be a better choice for automating such systems. In this work, a novel technique for vehicle detection from the images obtained from high resolution sensors is proposed. Though we are using high resolution images, vehicles are seen only as tiny spots, difficult to distinguish from the background. But we are able to obtain a detection rate not less than 0.9. Thereafter we classify the detected vehicles into cars and trucks and find the count of them.

  20. Using High Resolution SPOT 5 Multispectral Imagery for Crop Identification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High resolution satellite imagery offers new opportunities for crop monitoring and assessment. A SPOT 5 image with four spectral bands (green, red, near-infrared, and mid-infrared) and 10-m pixel size covering intensively cropped areas in south Texas was evaluated for crop identification. Two images...

  1. Mapping riparian and wetland weeds with high resolution satellite imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquatic and wetland weeds are a serious management problem in many freshwater ecosystems of the world. This paper presents an overview on the application of using high resolution QuickBird multi-spectral satellite imagery for detecting weeds in waterways and wetlands in Texas. Unsupervised image a...

  2. High Resolution Wavenumber Standards for the Infrared. (IUPAC Recommendations 1995)

    NASA Technical Reports Server (NTRS)

    Guelachvili, G.; Birk, M.; Borde, C. J.; Brault, J. W.; Brown, L. R.; Carli, B.; Cole, A. R. H.; Evenson, K. M.; Fayt, A.; Hausamann, D.; Johns, J. W. C.; Kauppinen, J.; Kou, Q.; Maki, A. G.; Rao, K. N.; Toth, R. A.; Urban, W.; Valentin, A.; Verges, J.; Wagner, G.; Wappelhorst, M. H.; Wells, J. S.; Winnewisser, B. P.; Winnewisser, M.

    1995-01-01

    The calibration of high resolution infrared spectra is generally more precise than accurate. This is the case even when they are recorded with Fourier transform interferometers. This presentation aims at improving the accuracy of wavenumber measurements in the infrared by recommending a selection of spectral lines as wavenumber standards for absolute calibration.

  3. High-Resolution Fluorometer for Mapping Microscale Phytoplankton Distributions

    PubMed Central

    Doubell, Mark J.; Seuront, Laurent; Seymour, Justin R.; Patten, Nicole L.; Mitchell, James G.

    2006-01-01

    A new high-resolution, in situ profiling fluorometer maps fluorescence distributions with a spatial resolution of 0.5 to 1.5 mm to a depth of 70 m in the open ocean. We report centimeter-scale patterns for phytoplankton distributions associated with gradients exhibiting 10- to 30-fold changes in fluorescence in contrasting marine ecosystems. PMID:16751572

  4. High-resolution fluorometer for mapping microscale phytoplankton distributions.

    PubMed

    Doubell, Mark J; Seuront, Laurent; Seymour, Justin R; Patten, Nicole L; Mitchell, James G

    2006-06-01

    A new high-resolution, in situ profiling fluorometer maps fluorescence distributions with a spatial resolution of 0.5 to 1.5 mm to a depth of 70 m in the open ocean. We report centimeter-scale patterns for phytoplankton distributions associated with gradients exhibiting 10- to 30-fold changes in fluorescence in contrasting marine ecosystems. PMID:16751572

  5. Homology Groups of High-Resolution Temporal Rainfall

    NASA Astrophysics Data System (ADS)

    Fernández, Félix; Vásquez Aguilar, Raciel; Carsteanu, Alin-Andrei

    2016-04-01

    This study applies topological data analysis, by generating homology groups to uncover patterns in the data of high-resolution temporal rainfall intensities from Iowa City (IIHR, U of Iowa). The state-space representation of the data is being investigated for an appropiate embedding dimension, in order to subsequently study topological properties of resulting manifold.

  6. Evaluating high resolution SPOT 5 satellite imagery for crop identification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High resolution satellite imagery offers new opportunities for crop monitoring and assessment. A SPOT 5 image with four spectral bands (green, red, near-infrared, and mid-infrared) and 10-m pixel size covering intensively cropped areas in south Texas was evaluated for crop identification. Two images...

  7. A DVD Spectroscope: A Simple, High-Resolution Classroom Spectroscope

    ERIC Educational Resources Information Center

    Wakabayashi, Fumitaka; Hamada, Kiyohito

    2006-01-01

    Digital versatile disks (DVDs) have successfully made up an inexpensive but high-resolution spectroscope suitable for classroom experiments that can easily be made with common material and gives clear and fine spectra of various light sources and colored material. The observed spectra can be photographed with a digital camera, and such images can…

  8. HIGH RESOLUTION RESISTIVITY LEAK DETECTION DATA PROCESSING & EVALUATION MEHTODS & REQUIREMENTS

    SciTech Connect

    SCHOFIELD JS

    2007-10-04

    This document has two purposes: {sm_bullet} Describe how data generated by High Resolution REsistivity (HRR) leak detection (LD) systems deployed during single-shell tank (SST) waste retrieval operations are processed and evaluated. {sm_bullet} Provide the basic review requirements for HRR data when Hrr is deployed as a leak detection method during SST waste retrievals.

  9. High resolution X-ray spectroscopy using microcalorimeters

    NASA Technical Reports Server (NTRS)

    Kelley, R. L.; Holt, S. S.; Madejski, G. M.; Moseley, S. H.; Schoelkopf, R. J.; Szymkowiak, A. E.

    1988-01-01

    The use of microcalorimeters for high-resolution, high quantum efficiency, nondispersive X-ray spectroscopy has been demonstrated over the past few years. In this paper, the principles of X-ray calorimetry are reviewed, and the results of ongoing X-ray tests using microcalorimetry are summarized. An approach to building an X-ray calorimeter spectrometer is discussed.

  10. Dual camera system for acquisition of high resolution images

    NASA Astrophysics Data System (ADS)

    Papon, Jeremie A.; Broussard, Randy P.; Ives, Robert W.

    2007-02-01

    Video surveillance is ubiquitous in modern society, but surveillance cameras are severely limited in utility by their low resolution. With this in mind, we have developed a system that can autonomously take high resolution still frame images of moving objects. In order to do this, we combine a low resolution video camera and a high resolution still frame camera mounted on a pan/tilt mount. In order to determine what should be photographed (objects of interest), we employ a hierarchical method which first separates foreground from background using a temporal-based median filtering technique. We then use a feed-forward neural network classifier on the foreground regions to determine whether the regions contain the objects of interest. This is done over several frames, and a motion vector is deduced for the object. The pan/tilt mount then focuses the high resolution camera on the next predicted location of the object, and an image is acquired. All components are controlled through a single MATLAB graphical user interface (GUI). The final system we present will be able to detect multiple moving objects simultaneously, track them, and acquire high resolution images of them. Results will demonstrate performance tracking and imaging varying numbers of objects moving at different speeds.

  11. Plant respirometer enables high resolution of oxygen consumption rates

    NASA Technical Reports Server (NTRS)

    Foster, D. L.

    1966-01-01

    Plant respirometer permits high resolution of relatively small changes in the rate of oxygen consumed by plant organisms undergoing oxidative metabolism in a nonphotosynthetic state. The two stage supply and monitoring system operates by a differential pressure transducer and provides a calibrated output by digital or analog signals.

  12. High Resolution Mass Spectra Analysis with a Programmable Calculator.

    ERIC Educational Resources Information Center

    Holdsworth, David K.

    1980-01-01

    Highlighted are characteristics of programs written for a pocket-sized programmable calculator to analyze mass spectra data (such as displaying high resolution masses for formulas, predicting whether formulas are stable molecules or molecular ions, determining formulas by isotopic abundance measurement) in a laboratory or classroom. (CS)

  13. Persistence Diagrams of High-Resolution Temporal Rainfall

    NASA Astrophysics Data System (ADS)

    Fernández Méndez, F.; Carsteanu, A. A.

    2015-12-01

    This study applies Topological Data Analysis (TDA), by generating persistence diagrams to uncover patterns in the data of high-resolution temporal rainfall intensities from Iowa City (IIHR, U of Iowa). Persistence diagrams are a way to identify essential cycles in state-space representations of the data.

  14. Linear Actuator Has Long Stroke and High Resolution

    NASA Technical Reports Server (NTRS)

    Cook, Brant T.; Moore, Donald M.; Braun, David F.; Koenig, John S.; Hankins, Steve M.

    2009-01-01

    The term precision linear actuator, direct drive ( PLADD ) refers to a robust linear actuator designed to be capable of repeatedly performing, over a lifetime of the order of 5 to 10 years, positioning maneuvers that include, variously, submicron increments or slews of the order of a centimeter. The PLADD is capable of both long stroke (120 mm) and high resolution (repeatable increments of 20 nm). Unlike precise linear actuators of prior design, the PLADD contains no gears, levers, or hydraulic converters. The PLADD, now at the prototype stage of development, is intended for original use as a coarse-positioning actuator in a spaceborne interferometer. The PLADD could also be adapted to terrestrial applications in which there are requirements for long stroke and high resolution: potential applications include medical imaging and fabrication of semiconductor devices. The PLADD (see figure) includes a commercially available ball-screw actuator driven directly by a commercially available three-phase brushless DC motor. The ball-screw actuator comprises a spring-preloaded ball nut on a ball screw that is restrained against rotation as described below. The motor is coupled directly (that is, without an intervening gear train) to a drive link that, in turn, is coupled to the ball nut. By eliminating the gear train, the direct-drive design eliminates the complexity, backlash, and potential for misalignment associated with a gear train. To prevent inadvertent movement, there is a brake that includes flexured levers compressed against the drive link by preload springs. This is a power-off brake: There are also piezoelectric stacks that can be activated to oppose the springs and push the levers away from the drive link. Hence, power must be applied to the piezoelectric stacks to release the drive link from braking. To help ensure long operational life, all of the mechanical drive components are immersed in an oil bath within hermetically sealed bellows. The outer end of the

  15. High Resolution Ionospheric Mapping Using Spaceborne Synthetic Aperture Radars

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; Chotoo, K.; Roth, A. P.

    2012-12-01

    properties, and (if applicable) geographic location. Three case studies will be presented to highlight the type and quality of ionospheric information that can be retrieved: (1) The high spatial resolution of SAR-derived TEC maps is emphasized in a case study that focuses on high resolution mapping of aurora arcs in central Alaska. Here, TEC enhancements associated with aurora activity are mapped and compared to reference observations from sky cameras and GPS; (2) observations of mid-latitudal traveling ionospheric disturbances are shown to showcase the accuracy of SAR-derived TEC maps. Several SAR-based TEC mapping methods are compared to highlight their respective advantages and disadvantages regarding processing complexity and estimation accuracy; (3) a third example focuses on analyzing post-sunset scintillation phenomena in equatorial regions. SAR is used to assess the frequency of occurrence of scintillation and analyze their associated power spectra. To conclude the paper, the temporal and spatial sampling of the ionosphere provided by the fleet of current and future spaceborne SAR sensors is analyzed to provide an assessment of the global ionospheric mapping capabilities of SAR.

  16. Simulation of the mantle and crustal Helium isotope signature in the Mediterranean Sea using a high resolution regional circulation model

    NASA Astrophysics Data System (ADS)

    Ayache, Mohamed; Dutay, Jean-claude; Jean-baptiste, Philippe

    2015-04-01

    Helium isotopes (3He, 4He) are useful tracers for investigating the deep ocean circulation and for evaluating ocean general circulation models, because helium is a stable and conservative nuclide that does not take part in any chemical or biological processes. Helium in the ocean originates from three different sources: namely, (i) gas dissolution in equilibrium with atmospheric helium, (ii) helium-3 addition by radioactive decay of tritium (called tritiugenic helium), and (iii) injection of helium-3 and helium-4 by the submarine volcanic activity which occurs mainly at plate boundaries, and also addition of helium-4 from the crust and sedimentary cover by α-decay of uranium and thorium contained in various minerals (called terrigenic helium). Here we present the first simulation of the helium isotope distribution in the whole Mediterranean Sea, using a high resolution model (NEMO-MED12). The simulation was produced by building a simple source function for helium produced by submarine volcanic degassing in the main active areas of the Mediterranean, and by crustal degassing at sea bottom, based on previous estimates of the total flux of helium into the oceans. In addition to providing constraints on the degassing flux, our work provides information on the variability of the thermohaline circulation and the ventilation of the deep waters to constrain the degree to which the NEMO-MED12 can reproduce correctly the main hydrographic features of the Mediterranean Sea circulation. This study is part of the work carried out to assess the robustness of the NEMO-MED12 model, which will be used to study the evolution of the climate and its effect on the biogeochemical cycles in the Mediterranean Sea, and to improve our ability to predict the future evolution of the Mediterranean Sea under the increasing anthropogenic pressure.

  17. Ambient Observations of Organic Nitrogen Compounds in Submicrometer Aerosols in New York Using High Resolution Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Zhou, S.; Ge, X.; Xu, J.; Sun, Y.; Zhang, Q.

    2015-12-01

    Organic nitrogen (ON) compounds, which include amines, nitriles, organic nitrates, amides, and N-containing aromatic heterocycles, are an important class of compounds ubiquitously detected in atmospheric particles and fog and cloud droplets. Previous studies indicate that these compounds can make up a significant fraction (20-80%) of the total nitrogen (N) content in atmospheric condensed phases and play important roles in new particle formation and growth and affecting the optical and hygroscopicity of aerosols. In this study, we report the observation of ON compounds in submicrometer particles (PM1) at two locations in New York based on measurements using Aerodyne high-resolution time-of-flight mass spectrometer (HR-ToF-AMS). One study was conducted as part of the US Department of Energy funded Aerosol Lifecyle - Intensive Operation Period (ALC-IOP) campaign at Brookhaven National Lab (BNL, 40.871˚N, 72.89˚W) in summer, 2011 and the other was conducted at the Queen's College (QC) in New York City (NYC) in summer, 2009. We observed a notable amount of N-containing organic fragment ions, CxHyNp+ and CxHyOzNp+, in the AMS spectra of organic aerosols at both locations and found that they were mainly associated with amino functional groups. Compared with results from lab experiments, the C3H8N+ at m/z = 58 was primarily attributed to trimethylamine. In addition, a significant amount of organonitrates was observed at BNL. Positive matrix factorization (PMF) analysis of the high resolution mass spectra (HRMS) of organic aerosols identified a unique nitrogen-enriched OA (NOA) factor with elevated nitrogen-to-carbon (N/C) at both BNL and QC. Analysis of the size distributions, volatility profiles, and correlations with external tracer indicates that acid-base reactions of amino compounds with sulfate and acidic gas were mainly responsible for the formation of amine salts. Photochemical production was also observed to play a role in the formation of NOA. Bivariate polar

  18. High-resolution measurements of humidity and temperature with lidar

    NASA Astrophysics Data System (ADS)

    Behrendt, Andreas; Wulfmeyer, Volker; Spaeth, Florian; Hammann, Eva; Muppa, Shravan Kumar; Metzendorf, Simon; Riede, Andrea

    2015-04-01

    3-dimensional thermodynamic fields of temperature and moisture including their turbulent fluctuations have been observed with the two scanning lidar systems of University of Hohenheim in three field campaigns in 2013 and 2014. In this contribution, we will introduce these two self-developed instruments and illustrate their performance with measurement examples. Finally, an outlook to envisioned future research activities with the new data sets of the instruments is given. Our temperature lidar is based on the rotational Raman technique. The scanning rotational Raman lidar (RRL) uses a seeded frequency-doubled Nd:YAG laser at a wavelength of 355 nm. A two-mirror scanner with a 40-cm telescope collects the atmospheric backscatter signals. Humidity measurements are made with a scanning water vapor differential absorption lidar (DIAL) which uses a titanium sapphire laser at 820 nm as transmitter. This laser is pumped with a frequency-doubled Nd:YAG laser and injection-seeded for switching between the online and offline wavelengths. The DIAL receiver consists of a scanning 80-cm telescope. The measured temperature and humidity profiles of both instruments have typical resolutions of only a few seconds and 100 m in the atmospheric boundary layer both in day- and night-time. Recent field experiments with the RRL and the DIAL of University of Hohenheim were (1) the HD(CP)2 Prototype Experiment (HOPE) in spring 2013 in western Germany - this activity is embedded in the project HD(CP)2 (High-definition clouds and precipitation for advancing climate prediction); (2) a measurement campaign in Hohenheim in autumn 2013; (3) the campaign SABLE (Surface Atmospheric Boundary Layer Exchange) in south-western Germany in summer 2014. The collected moisture and temperature data will serve as initial thermodynamic fields for forecast experiments related to the formation of clouds and precipitation. Due to their high resolution and high precision, the systems are capable of resolving

  19. High-resolution DEM Effects on Geophysical Flow Models

    NASA Astrophysics Data System (ADS)

    Williams, M. R.; Bursik, M. I.; Stefanescu, R. E. R.; Patra, A. K.

    2014-12-01

    Geophysical mass flow models are numerical models that approximate pyroclastic flow events and can be used to assess the volcanic hazards certain areas may face. One such model, TITAN2D, approximates granular-flow physics based on a depth-averaged analytical model using inputs of basal and internal friction, material volume at a coordinate point, and a GIS in the form of a digital elevation model (DEM). The volume of modeled material propagates over the DEM in a way that is governed by the slope and curvature of the DEM surface and the basal and internal friction angles. Results from TITAN2D are highly dependent upon the inputs to the model. Here we focus on a single input: the DEM, which can vary in resolution. High resolution DEMs are advantageous in that they contain more surface details than lower-resolution models, presumably allowing modeled flows to propagate in a way more true to the real surface. However, very high resolution DEMs can create undesirable artifacts in the slope and curvature that corrupt flow calculations. With high-resolution DEMs becoming more widely available and preferable for use, determining the point at which high resolution data is less advantageous compared to lower resolution data becomes important. We find that in cases of high resolution, integer-valued DEMs, very high-resolution is detrimental to good model outputs when moderate-to-low (<10-15°) slope angles are involved. At these slope angles, multiple adjacent DEM cell elevation values are equal due to the need for the DEM to approximate the low slope with a limited set of integer values for elevation. The first derivative of the elevation surface thus becomes zero. In these cases, flow propagation is inhibited by these spurious zero-slope conditions. Here we present evidence for this "terracing effect" from 1) a mathematically defined simulated elevation model, to demonstrate the terracing effects of integer valued data, and 2) a real-world DEM where terracing must be

  20. High-resolution climate simulation of the last glacial maximum

    SciTech Connect

    Erickson III, David J

    2008-01-01

    The climate of the last glacial maximum (LGM) is simulated with a high-resolution atmospheric general circulation model, the NCAR CCM3 at spectral truncation of T170, corresponding to a grid cell size of roughly 75 km. The purpose of the study is to assess whether there are significant benefits from the higher resolution simulation compared to the lower resolution simulation associated with the role of topography. The LGM simulations were forced with modified CLIMAP sea ice distribution and sea surface temperatures (SST) reduced by 1 C, ice sheet topography, reduced CO{sub 2}, and 21,000 BP orbital parameters. The high-resolution model captures modern climate reasonably well, in particular the distribution of heavy precipitation in the tropical Pacific. For the ice age case, surface temperature simulated by the high-resolution model agrees better with those of proxy estimates than does the low-resolution model. Despite the fact that tropical SSTs were only 2.1 C less than the control run, there are many lowland tropical land areas 4-6 C colder than present. Comparison of T170 model results with the best constrained proxy temperature estimates (noble gas concentrations in groundwater) now yield no significant differences between model and observations. There are also significant upland temperature changes in the best resolved tropical mountain belt (the Andes). We provisionally attribute this result in part as resulting from decreased lateral mixing between ocean and land in a model with more model grid cells. A longstanding model-data discrepancy therefore appears to be resolved without invoking any unusual model physics. The response of the Asian summer monsoon can also be more clearly linked to local geography in the high-resolution model than in the low-resolution model; this distinction should enable more confident validation of climate proxy data with the high-resolution model. Elsewhere, an inferred salinity increase in the subtropical North Atlantic may have

  1. High-resolution MEA platform for in-vitro electrogenic cell networks imaging.

    PubMed

    Imfeld, K; Garenne, A; Neukom, S; Maccione, A; Martinoia, S; Koudelka-Hep, M; Berdondini, L

    2007-01-01

    A platform based on an active-pixel-sensor electrode array (APS-MEA) for high-resolution imaging of in-vitro electrogenic cell cultures is presented, characterized and validated under culture conditions. The system enables full frame acquisition at 8 kHz from 4096 microelectrodes integrated with separations of 21 microm and zoomed area acquisition with temporal resolutions down to 8 micros. This bi-modal acquisition feature opens new perspectives in particular for neuronal activity analysis and for the correlation of micro-scale and macro-scale behaviors. The low-noise performances of the integrated amplifier (11 microVRMS) combined with a hardware implementation reflecting image-/video-concepts enable high-resolution acquisitions with real-time processing capabilities adapted to the handling of the large amount of acquired data. PMID:18003403

  2. Ganymede Uruk Sulcus High Resolution Mosaic Shown in Context

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A mosaic of four Galileo high-resolution images of the Uruk Sulcus region of Jupiter's moon Ganymede (Latitude 11 N, Longitude: 170 W) is shown within the context of an image of the region taken by Voyager 2 in 1979, which in turn is shown within the context of a full-disk image of Ganymede. North is to the top of the picture, and the sun illuminates the surface from the lower left, nearly overhead. The area shown is about 120 by 110 kilometers (75 by 68 miles) in extent and the smallest features that can be discerned are 74 meters (243 feet) in size in the Galileo images and 1.3 kilometers (0.8 miles) in the Voyager data. The higher resolution Galileo images unveil the details of parallel ridges and troughs that are principal features in the brighter regions of Ganymede. High photometric activity (large light contrast at high spatial frequencies) of this ice-rich surface was such that the Galileo camera's hardware data compressor was pushed into truncating lines. The north-south running gap between the left and right halves of the mosaic is a result of line truncation from the normal 800 samples per line to about 540. The images were taken on 27 June, 1996 Universal Time at a range of 7,448 kilometers (4,628 miles) through the clear filter of the Galileo spacecraft's imaging system.

    Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment.

    The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo.

  3. High resolution gas chromatography analysis of rice bran oil

    NASA Astrophysics Data System (ADS)

    Yu, Fengxiang; Lin, Qinlu; Chen, Xu; Wei, Xiaojun

    To assess the nutritional value and safety quality of rice bran oil (RBO) ,fatty acids of RBO from 15 species rice come from Hunan Province were analyzed by high resolution gas chromatography (HRGC). Crude RBOs were extracted by hexane 3-times using a solvent-to-rice bran ratio of 3:1 (w/w) at 40°C and composition of RBOs was analyzed by HRGC. The result showed that main fatty acids of 15 kinds of RBO include myristic acid (C14:0), palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), linolenic acid (C18:3), arachidic acid (C20:0), arachidonic acid (C20:1). It is strange that arachidonic acid (C20:1) is not listed in Chinese standard of RBO (GB11192-2003), and it exists in our samples of RBO. The average value of linolenic acid in RBOs is 1.6304% (range from 1.2425% to 2.131%), and it showed higher level comparing with Chinese standard that linolenic acid is less than 1.0%. The average value of USFA and SFA are 76.81% (range 75.96% to 82.06% ) and 20.15% (range 13.72% to 23.06%) respectively, and USFA content is close to olive oil (83.75%), peanut oil (81.75%) and soybean oil (85.86%). USFA in Jingyou 13 RBO is the highest content. The ratio of USFA to SFA content is 4:1 (range from 3.32 to 5.98:1). The ratio of SFA: MUFA: PUFA of 15 RBOs is 1: 2.2: 1.8, and ω6/ω3 ratio is 21.69 (range from16.54 to 27.28) and it is close to the 26:1 which is reported to be helpful to increase SOD activity. The oleic acid /linoleic acid ratio of 15 RBOs is 1.23:1 (rang from 1.04:1 to 1.42:1). Our data analyzed composition of RBOs from 15 species rice of China and will provide new evidence to revise RBO standard. It also helps us to assess nutritional value of RBOs and identify different RBOs from various species rice and places of origin.

  4. High resolution modeling of a small urban catchment

    NASA Astrophysics Data System (ADS)

    Skouri-Plakali, Ilektra; Ichiba, Abdellah; Gires, Auguste; Tchiguirinskaia, Ioulia; Schertzer, Daniel

    2016-04-01

    Flooding is one of the most complex issues that urban environments have to deal with. In France, flooding remains the first natural risk with 72% of decrees state of natural disaster issued between October 1982 and mid-November 2014. Flooding is a result of meteorological extremes that are usually aggravated by the hydrological behavior of urban catchments and human factors. The continuing urbanization process is indeed changing the whole urban water cycle by limiting the infiltration and promoting runoff. Urban environments are very complex systems due to their extreme variability, the interference between human activities and natural processes but also the effect of the ongoing urbanization process that changes the landscape and hardly influences their hydrologic behavior. Moreover, many recent works highlight the need to simulate all urban water processes at their specific temporal and spatial scales. However, considering urban catchments heterogeneity still challenging for urban hydrology, even after advances noticed in term of high-resolution data collection and computational resources. This issue is more to be related to the architecture of urban models being used and how far these models are ready to take into account the extreme variability of urban catchments. In this work, high spatio-temporal resolution modeling is performed for a small and well-equipped urban catchment. The aim of this work is to identify urban modeling needs in terms of spatial and temporal resolution especially for a very small urban area (3.7 ha urban catchment located in the Perreux-sur-Marne city at the southeast of Paris) MultiHydro model was selected to carry out this work, it is a physical based and fully distributed model that interacts four existing modules each of them representing a portion of the water cycle in urban environments. MultiHydro was implemented at 10m, 5m and 2m resolution. Simulations were performed at different spatio-temporal resolutions and analyzed with

  5. Estimating Scots Pine Tree Mortality Using High Resolution Multispectral Images

    NASA Astrophysics Data System (ADS)

    Buriak, L.; Sukhinin, A. I.; Conard, S. G.; Ivanova, G. A.; McRae, D. J.; Soja, A. J.; Okhotkina, E.

    2010-12-01

    Scots pine (Pinus sylvestris) forest stands of central Siberia are characterized by a mixed-severity fire regime that is dominated by low- to high-severity surface fires, with crown fires occurring less frequently. The purpose of this study was to link ground measurements with air-borne and satellite observations of active wildfires and older fire scars to better estimate tree mortality remotely. Data from field sampling on experimental fires and wildfires were linked with intermediate-resolution satellite (Landsat Enhanced Thematic Mapper) data to estimate fire severity and carbon emissions. Results are being applied to Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) imagery, MERIS, Landsat-ETM, SPOT (i.e., low, middle and high spatial resolution), to understand their remote-sensing capability for mapping fire severity, as indicated by tree mortality. Tree mortality depends on fireline intensity, residence time, and the physiological effects on the cambium layer, foliage and roots. We have correlated tree mortality measured after fires of varying severity with NDVI and other Chlorophyll Indexes to model tree mortality on a landscape scale. The field data obtained on experimental and wildfires are being analyzed and compared with intermediate-resolution satellite data (Landsat7-ETM) to help estimate fire severity, emissions, and carbon balance. In addition, it is being used to monitor immediate ecosystem fire effects (e.g., tree mortality) and long-term postfire vegetation recovery. These data are also being used to validate AVHRR , MODIS, and MERIS estimates of burn area. We studied burned areas in the Angara Region of central Siberia (northeast of Lake Baikal) for which both ground data and satellite data (ENVISAT-MERIS, Spot4, Landsat5, Landsat7-ETM) were available for the 2003 - 2004 and 2006 - 2008 periods. Ground validation was conducted on seventy sample plots established on burned sites differing in

  6. Ring artifact correction for high-resolution micro CT.

    PubMed

    Kyriakou, Yiannis; Prell, Daniel; Kalender, Willi A

    2009-09-01

    In high-resolution micro CT using flat detectors (FD), imperfect or defect detector elements may cause concentric-ring artifacts due to their continuous over- or underestimation of attenuation values, which often disturb image quality. We here present a dedicated image-based ring artifact correction method for high-resolution micro CT, based on median filtering of the reconstructed image and working on a transformed version of the reconstructed images in polar coordinates. This post-processing method reduced ring artifacts in the reconstructed images and improved image quality for phantom and in in vivo scans. Noise and artifacts were reduced both in transversal and in multi-planar reformations along the longitudinal axis. PMID:19661571

  7. High Resolution Coherent 3d Spectroscopy of Bromine

    NASA Astrophysics Data System (ADS)

    Strangfeld, Benjamin R.; Wells, Thresa A.; House, Zuri R.; Chen, Peter C.

    2013-06-01

    The high resolution gas phase electronic spectrum of bromine is rather congested due to many overlapping vibrational and rotational transitions with similar transition frequencies, and also due to isotopomeric effects. Expansion into the second dimension will remove some of this congestion; however through the implementation of High Resolution Coherent 3D Spectroscopy, the density of peaks is further reduced by at least two orders of magnitude. This allows for the selective examination of a small number of spatially resolved multidimensional bands, separated by vibrational quantum number and by isotopomer, which facilitates the fitting of many rovibrational peaks in bromine. The ability to derive information about the molecular constants for the electronic states involved will be discussed.

  8. High Resolution Coherent Three-Dimensional Spectroscopy of Iodine

    NASA Astrophysics Data System (ADS)

    House, Zuri R.; Wells, Thresa A.; Chen, Peter C.; Strangfeld, Benjamin R.

    2013-06-01

    The heavy congestion found in many one-dimensional spectra can make it difficult to study many transitions. A new coherent three-dimensional spectroscopic technique has been developed to eliminate the kind of congestion commonly seen in high resolution electronic spectra. The molecule used for this test was Iodine. A well-characterized transition (X to B) was used to determine which four wave mixing process or processes were responsible for the peaks in the resulting multidimensional spectrum. The resolution of several peaks that overlap in a coherent 2D spectrum can be accomplished by using a higher dimensional (3D) spectroscopic method. This talk will discuss strategies for finding spectroscopic constants using this high resolution coherent 3D spectroscopic method.

  9. Strategies for Interpreting High Resolution Coherent Multidimensional Spectra

    NASA Astrophysics Data System (ADS)

    Wells, Thresa A.; House, Zuri R.; Chen, Peter C.; Strangfeld, Benjamin R.

    2013-06-01

    The electronic spectra of certain molecules can be very complex and consist of a high density of peaks. The high density of peaks results in severe spectral congestion, making conventional data analysis techniques extremely difficult to use. One solution to this problem is to use high resolution coherent 2D spectroscopy (HRC2DS), which can improve resolution and sort peaks into recognizable clusters. This technique requires new data analysis techniques to accurately assign peaks. Even though HRC2DS can improve spectral resolution, some regions of the spectra may still remain congested. The ability to solve this problem using even higher dimensional techniques (e.g., high resolution coherent 3D spectroscopy) with 3D pattern recognition and data analysis techniques will be discussed.

  10. An Introduction to High Resolution Coherent Multidimensional Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Peter C.; Wells, Thresa A.; House, Zuri R.; Strangfeld, Benjamin R.

    2013-06-01

    High resolution coherent multidimensional spectroscopy is a technique that can be used to analyze and assign peaks for molecules that have resisted spectral analysis. Molecules that yield heavily congested and seemingly patternless spectra using conventional methods can yield 2D spectra that have recognizable patterns. The off-diagonal region of the coherent 2D plot shows only cross-peaks that are related by rotational selection rules. The resulting patterns facilitate peak assignment if they are sufficiently resolved. For systems that are not well-resolved, coherent 3D spectra may be generated to further improve resolution and provide selectivity. This presentation will provide an introduction to high resolution coherent 2D and 3D spectroscopies.

  11. Fabricating High-Resolution X-Ray Collimators

    NASA Technical Reports Server (NTRS)

    Appleby, Michael; Atkinson, James E.; Fraser, Iain; Klinger, Jill

    2008-01-01

    A process and method for fabricating multi-grid, high-resolution rotating modulation collimators for arcsecond and sub-arcsecond x-ray and gamma-ray imaging involves photochemical machining and precision stack lamination. The special fixturing and etching techniques that have been developed are used for the fabrication of multiple high-resolution grids on a single array substrate. This technology has application in solar and astrophysics and in a number of medical imaging applications including mammography, computed tomography (CT), single photon emission computed tomography (SPECT), and gamma cameras used in nuclear medicine. This collimator improvement can also be used in non-destructive testing, hydrodynamic weapons testing, and microbeam radiation therapy.

  12. Analysis of Complex Steel Microstructures by High-Resolution EBSD

    NASA Astrophysics Data System (ADS)

    Isasti, Nerea; Jorge-Badiola, Denis; Alkorta, Jon; Uranga, Pello

    2016-01-01

    High-resolution electron backscattered diffraction (HR-EBSD) is a powerful tool to describe microstructures at the sub-micrometric scale that achieves a higher degree of angular accuracy compared with conventional EBSD. However, such an EBSD technique is time-consuming and requires data-intensive computing to save and postprocess the results obtained after each scan. In the current work, a simple strategy to transform conventional results into high-resolution results is put forward in an averaging statistical layout. This makes it possible to measure the misorientations more precisely and, subsequently, the geometrically necessary dislocations by lowering the typical noise generated from Hough transformation-based conventional EBSD. Different steel microstructures are analyzed in light of this strategy. The calculated dislocation densities for those microstructures are used as input values for evaluating the initial dislocation density contribution to the yield strength in a newly developed mechanical model.

  13. High-resolution imaging of cellular processes in Caenorhabditis elegans.

    PubMed

    Maddox, Amy S; Maddox, Paul S

    2012-01-01

    Differential interference contrast (DIC) imaging of Caenorhabditis elegans embryogenesis led to a Nobel Prize in Physiology or Medicine (Sulston et al., 1983) as did the first use of green fluorescent protein (GFP) in a transgenic C. elegans (Chalfie et al., 1994). Given that C. elegans is free living, does not require exceptional environmental control, and is optically clear, live imaging is a powerful tool in for this model system. Combining genetics with high-resolution imaging has continued to make important contributions to many fields. In this chapter, we discuss how certain aspects of high-resolution microscopy are implemented. This is not an exhaustive review of microscopy; it is meant to be a helpful guide and point of reference for some basic concepts in imaging. While these concepts are largely true for all biological imaging, they are chosen as particularly important for C. elegans. PMID:22226519

  14. Temperature-dependent high resolution absorption cross sections of propane

    NASA Astrophysics Data System (ADS)

    Beale, Christopher A.; Hargreaves, Robert J.; Bernath, Peter F.

    2016-10-01

    High resolution (0.005 cm-1) absorption cross sections have been measured for pure propane (C3H8). These cross sections cover the 2550-3500 cm-1 region at five temperatures (from 296 to 700 K) and were measured using a Fourier transform spectrometer and a quartz cell heated by a tube furnace. Calibrations were made by comparison to the integrated cross sections of propane from the Pacific Northwest National Laboratory. These are the first high resolution absorption cross sections of propane for the 3 μm region at elevated temperatures. The cross sections provided may be used to monitor propane in combustion environments and in astronomical sources such as the auroral regions of Jupiter, brown dwarfs and exoplanets.

  15. High resolution nitrogen dioxide observations: retrieval, evaluation, and interpretation

    NASA Astrophysics Data System (ADS)

    Lamsal, L. N.; Janz, S. J.; Krotkov, N. A.; Pickering, K. E.; Kowalewski, M. G.; Loughner, C.; Spurr, R. J. D.; Crawford, J. H.

    2015-12-01

    The Airborne Compact Atmospheric Mapper (ACAM) deployed during the DISCOVER-AQ Maryland field campaign made hyperspectral remote sensing measurements in the 304-910 nm range allowing observations of several tropospheric pollutants including nitrogen dioxide (NO2) at an unprecedented spatial resolution of 1.5x0.75 km2. We apply the DOAS method, include high resolution information for surface reflectivity and vertical distributions of NO2 and aerosols, and account for temporal variation in atmospheric NO2 to retrieve lower tropospheric NO2 column. We compare NO2 from ACAM with observations from in-situ aircraft, ground-based PANDORA, and space-based OMI, and NO2 simulation from air quality models. The high resolution ACAM measurements offer not only new insights into our understanding of atmospheric composition and chemistry through observation of sub-sampling variability in typical satellite and model resolutions, but also opportunities for algorithm improvements for upcoming geostationary air quality missions.

  16. High resolution reservoir geological modelling using outcrop information

    SciTech Connect

    Zhang Changmin; Lin Kexiang; Liu Huaibo

    1997-08-01

    This is China`s first case study of high resolution reservoir geological modelling using outcrop information. The key of the modelling process is to build a prototype model and using the model as a geological knowledge bank. Outcrop information used in geological modelling including seven aspects: (1) Determining the reservoir framework pattern by sedimentary depositional system and facies analysis; (2) Horizontal correlation based on the lower and higher stand duration of the paleo-lake level; (3) Determining the model`s direction based on the paleocurrent statistics; (4) Estimating the sandbody communication by photomosaic and profiles; (6) Estimating reservoir properties distribution within sandbody by lithofacies analysis; and (7) Building the reservoir model in sandbody scale by architectural element analysis and 3-D sampling. A high resolution reservoir geological model of Youshashan oil field has been built by using this method.

  17. Airborne laser scanning for high-resolution mapping of Antarctica

    NASA Astrophysics Data System (ADS)

    Csatho, Bea; Schenk, Toni; Krabill, William; Wilson, Terry; Lyons, William; McKenzie, Garry; Hallam, Cheryl; Manizade, Serdar; Paulsen, Timothy

    In order to evaluate the potential of airborne laser scanning for topographic mapping in Antarctica and to establish calibration/validation sites for NASA's Ice, Cloud and land Elevation Satellite (ICESat) altimeter mission, NASA, the U.S. National Science Foundation (NSF), and the U.S. Geological Survey (USGS) joined forces to collect high-resolution airborne laser scanning data.In a two-week campaign during the 2001-2002 austral summer, NASA's Airborne Topographic Mapper (ATM) system was used to collect data over several sites in the McMurdo Sound area of Antarctica (Figure 1a). From the recorded signals, NASA computed laser points and The Ohio State University (OSU) completed the elaborate computation/verification of high-resolution Digital Elevation Models (DEMs) in 2003. This article reports about the DEM generation and some exemplary results from scientists using the geomorphologic information from the DEMs during the 2003-2004 field season.

  18. High-resolution ultrasound imaging of cutaneous lesions

    PubMed Central

    Mandava, Anitha; Ravuri, Prabhakar Rao; Konathan, Rajyalaxmi

    2013-01-01

    High-resolution variable frequency ultrasound imaging is increasingly being used in the noninvasive evaluation of various cutaneous diseases. It plays a complimentary role to physical examination in the assessment of cutaneous lesions. It is the only imaging modality useful in the evaluation of superficial cutaneous lesions that are too small to be evaluated on computed tomography (CT) or magnetic resonance imaging (MRI) and is helpful in reducing invasive procedures like biopsies and fine needle aspirations. In this article, we seek to describe the relevance and basic principles of cutaneous ultrasound, imaging findings of normal skin, current applications of high-resolution ultrasound in the diagnosis and management of various dermatological conditions, along with the features of some commonly encountered lesions. PMID:24347861

  19. Spaceborne laser instruments for high-resolution mapping

    NASA Astrophysics Data System (ADS)

    Yu, Anthony W.; Krainak, Michael A.; Harding, David J.; Abshire, James B.; Sun, Xiaoli; Valett, Susan; Cavanaugh, John; Ramos-Izquierdo, Luis

    2010-02-01

    We discuss past, present and future spaceborne laser instruments for high-resolution mapping of Earth and planetary surfaces. Previous spaceborne-laser-altimeters projected and imaged a single laser spot for surface-height measurements. In contrast, the recent Lunar Orbiter Laser Altimeter (LOLA) instrument on the Lunar Reconnaissance Orbiter (LRO) uses a non-scanning multi-beam system for surface topography mapping. The multi-beam instrument facilitates surface slope measurement and reduces the time-to-completion for global high-resolution topographic mapping. We discuss our first-year progress on a three-year swath-mapping laser-altimetry Instrument Incubator Program (IIP) funded by the NASA Earth Science Technology Office (ESTO). Our IIP is a technology development program supporting the LIdar Surface Topography (LIST) space-flight mission that is a third-tier mission as recommended by the National Research Council (NRC) for NASA's Earth Science programs.

  20. Development of a high resolution and high dispersion Thomson parabola

    NASA Astrophysics Data System (ADS)

    Jung, D.; Hörlein, R.; Kiefer, D.; Letzring, S.; Gautier, D. C.; Schramm, U.; Hübsch, C.; Öhm, R.; Albright, B. J.; Fernandez, J. C.; Habs, D.; Hegelich, B. M.

    2011-01-01

    Here, we report on the development of a novel high resolution and high dispersion Thomson parabola for simultaneously resolving protons and low-Z ions of more than 100 MeV/nucleon necessary to explore novel laser ion acceleration schemes. High electric and magnetic fields enable energy resolutions of ΔE/E < 5% at 100 MeV/nucleon and impede premature merging of different ion species at low energies on the detector plane. First results from laser driven ion acceleration experiments performed at the Trident Laser Facility demonstrate high resolution and superior species and charge state separation of this novel Thomson parabola for ion energies of more than 30 MeV/nucleon.

  1. Development of a high resolution and high dispersion Thomson parabola.

    PubMed

    Jung, D; Hörlein, R; Kiefer, D; Letzring, S; Gautier, D C; Schramm, U; Hübsch, C; Öhm, R; Albright, B J; Fernandez, J C; Habs, D; Hegelich, B M

    2011-01-01

    Here, we report on the development of a novel high resolution and high dispersion Thomson parabola for simultaneously resolving protons and low-Z ions of more than 100 MeV/nucleon necessary to explore novel laser ion acceleration schemes. High electric and magnetic fields enable energy resolutions of ΔE∕E < 5% at 100 MeV/nucleon and impede premature merging of different ion species at low energies on the detector plane. First results from laser driven ion acceleration experiments performed at the Trident Laser Facility demonstrate high resolution and superior species and charge state separation of this novel Thomson parabola for ion energies of more than 30 MeV/nucleon. PMID:21280824

  2. High resolution computed tomography of advanced composite and ceramic materials

    NASA Technical Reports Server (NTRS)

    Yancey, R. N.; Klima, S. J.

    1991-01-01

    Advanced composite and ceramic materials are being developed for use in many new defense and commercial applications. In order to achieve the desired mechanical properties of these materials, the structural elements must be carefully analyzed and engineered. A study was conducted to evaluate the use of high resolution computed tomography (CT) as a macrostructural analysis tool for advanced composite and ceramic materials. Several samples were scanned using a laboratory high resolution CT scanner. Samples were also destructively analyzed at the locations of the scans and the nondestructive and destructive results were compared. The study provides useful information outlining the strengths and limitations of this technique and the prospects for further research in this area.

  3. Advances in DNA sequencing technologies for high resolution HLA typing.

    PubMed

    Cereb, Nezih; Kim, Hwa Ran; Ryu, Jaejun; Yang, Soo Young

    2015-12-01

    This communication describes our experience in large-scale G group-level high resolution HLA typing using three different DNA sequencing platforms - ABI 3730 xl, Illumina MiSeq and PacBio RS II. Recent advances in DNA sequencing technologies, so-called next generation sequencing (NGS), have brought breakthroughs in deciphering the genetic information in all living species at a large scale and at an affordable level. The NGS DNA indexing system allows sequencing multiple genes for large number of individuals in a single run. Our laboratory has adopted and used these technologies for HLA molecular testing services. We found that each sequencing technology has its own strengths and weaknesses, and their sequencing performances complement each other. HLA genes are highly complex and genotyping them is quite challenging. Using these three sequencing platforms, we were able to meet all requirements for G group-level high resolution and high volume HLA typing. PMID:26423536

  4. Protein-DNA binding in high-resolution

    PubMed Central

    Mahony, Shaun; Pugh, B. Franklin

    2015-01-01

    Recent advances in experimental and computational methodologies are enabling ultra-high resolution genome-wide profiles of protein-DNA binding events. For example, the ChIP-exo protocol precisely characterizes protein-DNA crosslinking patterns by combining chromatin immunoprecipitation (ChIP) with 5′ → 3′ exonuclease digestion. Similarly, deeply sequenced chromatin accessibility assays (e.g. DNase-seq and ATACseq) enable the detection of protected footprints at protein-DNA binding sites. With these techniques and others, we have the potential to characterize the individual nucleotides that interact with transcription factors, nucleosomes, RNA polymerases, and other regulatory proteins in a particular cellular context. In this review, we explain the experimental assays and computational analysis methods that enable high-resolution profiling of protein-DNA binding events. We discuss the challenges and opportunities associated with such approaches. PMID:26038153

  5. Scalable, flexible and high resolution patterning of CVD graphene.

    PubMed

    Hofmann, Mario; Hsieh, Ya-Ping; Hsu, Allen L; Kong, Jing

    2014-01-01

    The unique properties of graphene make it a promising material for interconnects in flexible and transparent electronics. To increase the commercial impact of graphene in those applications, a scalable and economical method for producing graphene patterns is required. The direct synthesis of graphene from an area-selectively passivated catalyst substrate can generate patterned graphene of high quality. We here present a solution-based method for producing patterned passivation layers. Various deposition methods such as ink-jet deposition and microcontact printing were explored, that can satisfy application demands for low cost, high resolution and scalable production of patterned graphene. The demonstrated high quality and nanometer precision of grown graphene establishes the potential of this synthesis approach for future commercial applications of graphene. Finally, the ability to transfer high resolution graphene patterns onto complex three-dimensional surfaces affords the vision of graphene-based interconnects in novel electronics. PMID:24189709

  6. Turbine component casting core with high resolution region

    DOEpatents

    Kamel, Ahmed; Merrill, Gary B.

    2014-08-26

    A hollow turbine engine component with complex internal features can include a first region and a second, high resolution region. The first region can be defined by a first ceramic core piece formed by any conventional process, such as by injection molding or transfer molding. The second region can be defined by a second ceramic core piece formed separately by a method effective to produce high resolution features, such as tomo lithographic molding. The first core piece and the second core piece can be joined by interlocking engagement that once subjected to an intermediate thermal heat treatment process thermally deform to form a three dimensional interlocking joint between the first and second core pieces by allowing thermal creep to irreversibly interlock the first and second core pieces together such that the joint becomes physically locked together providing joint stability through thermal processing.

  7. Effective Area of the AXAF High Resolution Camera (HRC)

    NASA Technical Reports Server (NTRS)

    Patnaude, Daniel; Pease, Deron; Donnelly, Hank; Juda, Mike; Jones, Christine; Murray, Steve; Zombeck, Martin; Kraft, Ralph; Kenter, Almus; Meehan, Gary; Meehan, Gary; Swartz, Doug; Elsner, Ron

    1998-01-01

    The AXAF High-Resolution Camera (HRC) was calibrated at NASA MSFC's X-Ray Calibration Facility (XRCF) during 1997 March and April. We have undertaken an analysis of the HRC effective area using all data presently available from the XRCF. We discuss our spectral fitting of the beam-normalization detectors (BNDs), our method of removing higher order contamination lines present in the spectra, and corrections for beam non-uniformities. We apply a model of photon absorption depth in order to fit a smooth curve to the quantum efficiency of the detector. This is then combined with the most recent model of the AXAF High-Resolution Mirror Assembly (HRMA) to determine the ensemble effective area versus energy for the HRC. We also address future goals and concerns.

  8. High-resolution adaptive optics test bed for vision science

    NASA Astrophysics Data System (ADS)

    Wilks, Scott C.; Thompson, Charles A.; Olivier, Scot S.; Bauman, Brian J.; Flath, Laurence M.; Silva, Dennis A.; Sawvel, Robert M.; Barnes, Thomas B.; Werner, John S.

    2002-02-01

    We discuss the design and implementation of a low-cost, high-resolution adaptive optics test-bed for vision research. It is well known that high-order aberrations in the human eye reduce optical resolution and limit visual acuity. However, the effects of aberration-free eyesight on vision are only now beginning to be studied using adaptive optics to sense and correct the aberrations in the eye. We are developing a high-resolution adaptive optics system for this purpose using a Hamamatsu Parallel Aligned Nematic Liquid Crystal Spatial Light Modulator. Phase-wrapping is used to extend the effective stroke of the device, and the wavefront sensing and wavefront correction are done at different wavelengths. Issues associated with these techniques will be discussed.

  9. High resolution map of light pollution over Poland

    NASA Astrophysics Data System (ADS)

    Netzel, Henryka; Netzel, Paweł

    2016-09-01

    In 1976 Berry introduced a simple mathematical equation to calculate artificial night sky brightness at zenith. In the original model cities, considered as points with given population, are only sources of light emission. In contrary to Berry's model, we assumed that all terrain surface can be a source of light. Emission of light depends on percent of built up area in a given cell. We based on Berry's model. Using field measurements and high-resolution data we obtained the map of night sky brightness over Poland in 100-m resolution. High resolution input data, combined with a very simple model, makes it possible to obtain detailed structures of the night sky brightness without complicating the calculations.

  10. High-resolution dynamical modelling of the Antarctic stratospheric vortex

    NASA Technical Reports Server (NTRS)

    Haynes, P. H.

    1988-01-01

    Progress is reported on the high-resolution three-dimensional numerical simulation of flows characteristic of the Antarctic wintertime stratosphere. The numerical model is a modified version of the Reading University sigma-coordinate used previously for tropospheric studies. Physical parameterizations are kept to a minimum in order to concentrate as much computing power as possible on simulating details of the dynamical processes. The major question addressed is whether the features observed in recent high-resolution two-dimensional simulations - namely: (1) the formation of a sharp edge to the vortex (seen in the potential vorticity field), (2) the survival of the polar vortex in a material entity, and (3) the formation of small-scale eddies rough the break-up of tongues of high potential vorticity drawn out from the polar vortex - are realized in three-dimensional simulations.

  11. High-resolution studies of atmospheric IR emission spectra

    NASA Technical Reports Server (NTRS)

    Murcray, F. J.; Murcray, F. H.; Goldman, A.; Blatherwick, R. D.; Murcray, D. G.

    1991-01-01

    Atmospheric emission spectra obtained with two different spectrometer systems are presented. The first system (the BOMEM Michelson interferometer) is designed for emission work. Spectra were obtained under adverse conditions in the Antarctic, and are still of good absolute accuracy. The second system (a modified Bruker Instruments IFS120 very high spectral resolution interferometer) demonstrates the sensitivity that can be achieved even at higher spectral resolution. This system shows that mid-IR atmospheric emission spectra can be obtained with a good SNR in a reasonable length of time at a relatively high resolution. A properly designed high resolution system should achieve high accuracy, sensitivity, and resolution, thereby permitting measurements of many atmospheric constituents when solar spectra cannot be obtained.

  12. Dynamical downscaling inter-comparison for high resolution climate reconstruction

    NASA Astrophysics Data System (ADS)

    Ferreira, J.; Rocha, A.; Castanheira, J. M.; Carvalho, A. C.

    2012-04-01

    In the scope of the project: "High-resolution Rainfall EroSivity analysis and fORecasTing - RESORT", an evaluation of various methods of dynamic downscaling is presented. The methods evaluated range from the classic method of nesting a regional model results in a global model, in this case the ECMWF reanalysis, to more recently proposed methods, which consist in using Newtonian relaxation methods in order to nudge the results of the regional model to the reanalysis. The method with better results involves using a system of variational data assimilation to incorporate observational data with results from the regional model. The climatology of a simulation of 5 years using this method is tested against observations on mainland Portugal and the ocean in the area of the Portuguese Continental Shelf, which shows that the method developed is suitable for the reconstruction of high resolution climate over continental Portugal.

  13. High Resolution Scanning Electron Microscopy of Cells Using Dielectrophoresis

    PubMed Central

    Tang, Shi-Yang; Zhang, Wei; Soffe, Rebecca; Nahavandi, Sofia; Shukla, Ravi; Khoshmanesh, Khashayar

    2014-01-01

    Ultrastructural analysis of cells can reveal valuable information about their morphological, physiological, and biochemical characteristics. Scanning electron microscopy (SEM) has been widely used to provide high-resolution images from the surface of biological samples. However, samples need to be dehydrated and coated with conductive materials for SEM imaging. Besides, immobilizing non-adherent cells during processing and analysis is challenging and requires complex fixation protocols. In this work, we developed a novel dielectrophoresis based microfluidic platform for interfacing non-adherent cells with high-resolution SEM at low vacuum mode. The system enables rapid immobilization and dehydration of samples without deposition of chemical residues over the cell surface. Moreover, it enables the on-chip chemical stimulation and fixation of immobilized cells with minimum dislodgement. These advantages were demonstrated for comparing the morphological changes of non-budding and budding yeast cells following Lyticase treatment. PMID:25089528

  14. High-resolution streaming video integrated with UGS systems

    NASA Astrophysics Data System (ADS)

    Rohrer, Matthew

    2010-04-01

    Imagery has proven to be a valuable complement to Unattended Ground Sensor (UGS) systems. It provides ultimate verification of the nature of detected targets. However, due to the power, bandwidth, and technological limitations inherent to UGS, sacrifices have been made to the imagery portion of such systems. The result is that these systems produce lower resolution images in small quantities. Currently, a high resolution, wireless imaging system is being developed to bring megapixel, streaming video to remote locations to operate in concert with UGS. This paper will provide an overview of how using Wifi radios, new image based Digital Signal Processors (DSP) running advanced target detection algorithms, and high resolution cameras gives the user an opportunity to take high-powered video imagers to areas where power conservation is a necessity.

  15. Single-sided sensor for high-resolution NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Perlo, J.; Casanova, F.; Blümich, B.

    2006-06-01

    The unavoidable spatial inhomogeneity of the static magnetic field generated by open sensors has precluded their use for high-resolution NMR spectroscopy. In fact, this application was deemed impossible because these field variations are usually orders of magnitude larger than those created by the microscopic structure of the molecules to be detected. Recently, chemical shift resolved NMR spectra were observed for the first time outside a portable single-sided magnet by implementing a method that exploits inhomogeneities in the rf field designed to reproduce variations of the static magnetic field [J. Perlo, V. Demas, F. Casanova, C.A. Meriles, J. Reimer, A. Pines, B. Blümich, High-resolution spectroscopy with a portable single-sided sensor, Science 308 (2005) 1279]. In this communication, we describe in detail the magnet system built from permanent magnets as well as the rf coil geometry used to compensate the static field variations.

  16. The theory and practice of high resolution scanning electron microscopy

    SciTech Connect

    Joy, D.C. Oak Ridge National Lab., TN )

    1990-01-01

    Recent advances in instrumentation have produced the first commercial examples of what can justifiably be called High Resolution Scanning Electron Microscopes. The key components of such instruments are a cold field emission gun, a small-gap immersion probe-forming lens, and a clean dry-pumped vacuum. The performance of these microscopes is characterized by several major features including a spatial resolution, in secondary electron mode on solid specimens, which can exceed 1nm on a routine basis; an incident probe current density of the order of 10{sup 6} amps/cm{sup 2}; and the ability to maintain these levels of performance over an accelerating voltage range of from 1 to 30keV. This combination of high resolution, high probe current, low contamination and flexible electron-optical conditions provides many new opportunitites for the application of the SEM to materials science, physics, and the life sciences. 27 refs., 14 figs.

  17. Isotope ratios of uranium using high resolution inductively coupled plasma-mass spectrometry (ICP-MS)

    SciTech Connect

    Hearn, R.; Wildner, H.

    1998-12-31

    Actinide element isotope ratios have been determined in environmental samples using high resolution ICP-MS with ultrasonic nebulization. Precisions as low as 0.1% RSD have been achieved using various methods of acquisition. The methodology has been used for environmental monitoring of uranium isotope ratios as an indicator of nuclear activity. Also, it has been applied to calcite dating studies as a measure of past geochemical disturbances.

  18. Operation and maintenance manual for the high resolution stereoscopic video camera system (HRSVS) system 6230

    SciTech Connect

    Pardini, A.F., Westinghouse Hanford

    1996-07-16

    The High Resolution Stereoscopic Video Cameral System (HRSVS),system 6230, is a stereoscopic camera system that will be used as an end effector on the LDUA to perform surveillance and inspection activities within Hanford waste tanks. It is attached to the LDUA by means of a Tool Interface Plate (TIP), which provides a feed through for all electrical and pneumatic utilities needed by the end effector to operate.

  19. A high resolution cavity BPM for the CLIC Test Facility

    SciTech Connect

    Chritin, N.; Schmickler, H.; Soby, L.; Lunin, A.; Solyak, N.; Wendt, M.; Yakovlev, V.; /Fermilab

    2010-08-01

    In frame of the development of a high resolution BPM system for the CLIC Main Linac we present the design of a cavity BPM prototype. It consists of a waveguide loaded dipole mode resonator and a monopole mode reference cavity, both operating at 15 GHz, to be compatible with the bunch frequencies at the CLIC Test Facility. Requirements, design concept, numerical analysis, and practical considerations are discussed.

  20. The Goddard High Resolution Spectrograph: Instrument, goals, and science results

    NASA Astrophysics Data System (ADS)

    Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Ake, T. B.; Bruhweiler, F.; Cardelli, J. A.; Lindler, D. J.; Malumuth, E.; Randall, C. E.; Robinson, R.; Shore, S. N.; Wahlgren, G.

    1994-08-01

    The Goddard High Resolution Spectrograph (GHRS), currently in Earth orbit on the Hubble Space Telescope (HST), operates in the wavelength range 1150-3200 A with spectral resolutions (lambda/delta lambda) of approximately 2 x 103, 2 x 104, and 1 x 103. The instrument and its development from inception, its current status, the approach to operations, representative results in the major areas of the scientific goals, and prospects for the future are described.