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Sample records for active region generate

  1. Terahertz generation in mid-infrared quantum cascade lasers with a dual-upper-state active region

    SciTech Connect

    Fujita, Kazuue Hitaka, Masahiro; Ito, Akio; Edamura, Tadataka; Yamanishi, Masamichi; Jung, Seungyong; Belkin, Mikhail A.

    2015-06-22

    We report the performance of room temperature terahertz sources based on intracavity difference-frequency generation in mid-infrared quantum cascade lasers with a dual-upper-state (DAU) active region. DAU active region design is theoretically expected to produce larger optical nonlinearity for terahertz difference-frequency generation, compared to the active region designs of the bound-to-continuum type used previously. Fabricated buried heterostructure devices with a two-section buried distributed feedback grating and the waveguide designed for Cherenkov difference-frequency phase-matching scheme operate in two single-mode mid-infrared wavelengths at 10.7 μm and 9.7 μm and produce terahertz output at 2.9 THz with mid-infrared to terahertz conversion efficiency of 0.8 mW/W{sup 2} at room temperature.

  2. Trend of photospheric helicity flux in active regions generating halo CMEs

    NASA Astrophysics Data System (ADS)

    Smyrli, Aimilia; Zuccarello, Francesco; Zuccarello, Francesca; Romano, Paolo; Guglielmino, Salvatore Luigi; Spadaro, Daniele; Hood, Alan; Mackay, Duncan

    Coronal Mass Ejections (CMEs) are very energetic events initiated in the solar atmosphere, re-sulting in the expulsion of magnetized plasma clouds that propagate into interplanetary space. It has been proposed that CMEs can play an important role in shedding magnetic helicity, avoiding its endless accumulation in the corona. We therefore investigated the behavior of magnetic helicity accumulation in sites where the initiation of CMEs occurred, in order to de-termine whether and how changes in magnetic helicity accumulation are temporally correlated with CME occurrence. After identifying the active regions (AR) where the CMEs were ini-tiated by means of a double cross-check based on the flaring-eruptive activity and the use of SOHO/EIT difference images, we used MDI magnetograms to calculate magnetic flux evolu-tion, magnetic helicity injection rate and magnetic helicity injection in 10 active regions that gave rise to 12 halo CMEs observed during the period February 2000 -June 2003. No unique behavior in magnetic helicity injection accompanying halo CME occurrence is found. In fact, in some cases there is an abrupt change in helicity injection timely correlated with the CME event, while in some others no significant variation is recorded. However, our analysis show that the most significant changes in magnetic flux and magnetic helicity injection are associated with impulsive CMEs rather than gradual CMEs. Moreover, the most significant changes in mag-netic helicity are observed when X-class flares or eruptive filaments occur, while the occurrence of flares of class C or M seems not to affect significantly the magnetic helicity accumulation.

  3. Genome-Based Identification of Active Prophage Regions by Next Generation Sequencing in Bacillus licheniformis DSM13

    PubMed Central

    Hertel, Robert; Rodríguez, David Pintor; Hollensteiner, Jacqueline; Dietrich, Sascha; Leimbach, Andreas; Hoppert, Michael; Liesegang, Heiko; Volland, Sonja

    2015-01-01

    Prophages are viruses, which have integrated their genomes into the genome of a bacterial host. The status of the prophage genome can vary from fully intact with the potential to form infective particles to a remnant state where only a few phage genes persist. Prophages have impact on the properties of their host and are therefore of great interest for genomic research and strain design. Here we present a genome- and next generation sequencing (NGS)-based approach for identification and activity evaluation of prophage regions. Seven prophage or prophage-like regions were identified in the genome of Bacillus licheniformis DSM13. Six of these regions show similarity to members of the Siphoviridae phage family. The remaining region encodes the B. licheniformis orthologue of the PBSX prophage from Bacillus subtilis. Analysis of isolated phage particles (induced by mitomycin C) from the wild-type strain and prophage deletion mutant strains revealed activity of the prophage regions BLi_Pp2 (PBSX-like), BLi_Pp3 and BLi_Pp6. In contrast to BLi_Pp2 and BLi_Pp3, neither phage DNA nor phage particles of BLi_Pp6 could be visualized. However, the ability of prophage BLi_Pp6 to generate particles could be confirmed by sequencing of particle-protected DNA mapping to prophage locus BLi_Pp6. The introduced NGS-based approach allows the investigation of prophage regions and their ability to form particles. Our results show that this approach increases the sensitivity of prophage activity analysis and can complement more conventional approaches such as transmission electron microscopy (TEM). PMID:25811873

  4. Formation of sunspots and active regions through the emergence of magnetic flux generated in a solar convective dynamo

    NASA Astrophysics Data System (ADS)

    Chen, Feng; Rempel, Matthias D.; Fan, Yuhong

    2016-05-01

    We present a realistic numerical model of sunspot and active region formation through the emergence of flux tubes generated in a solar convective dynamo. The magnetic and velocity fields in a horizontal layer near the top boundary of the solar convective dynamo simulation are used as a time-dependent bottom boundary to drive the near surface layer radiation MHD simulations of magneto-convection and flux emergence with the MURaM code. The latter code simulates the emergence of the flux tubes through the upper most layer of the convection zone to the photosphere.The emerging flux tubes interact with the convection and break into small scale magnetic elements that further rise to the photosphere. At the photosphere, several bipolar pairs of sunspots are formed through the coalescence of the small scale magnetic elements. The sunspot pairs in the simulation successfully reproduce the fundamental observed properties of solar active regions, including the more coherent leading spots with a stronger field strength, and the correct tilts of the bipolar pairs. These asymmetries come most probably from the intrinsic asymmetries in the emerging fields imposed at the bottom boundary, where the horizontal fields are already tilted and the leading sides of the emerging flux tubes are usually up against the downdraft lanes of the giant cells. It is also found that penumbrae with numerous filamentary structures form in regions of strong horizontal magnetic fields that naturally comes from the ongoing flux emergence. In contrast to previous models, the penumbrae and umbrae are divided by very sharp boarders, which is highly consistent with observations.

  5. NON-NEUTRALIZED ELECTRIC CURRENT PATTERNS IN SOLAR ACTIVE REGIONS: ORIGIN OF THE SHEAR-GENERATING LORENTZ FORCE

    SciTech Connect

    Georgoulis, Manolis K.; Titov, Viacheslav S.; Mikic, Zoran

    2012-12-10

    Using solar vector magnetograms of the highest available spatial resolution and signal-to-noise ratio, we perform a detailed study of electric current patterns in two solar active regions (ARs): a flaring/eruptive and a flare-quiet one. We aim to determine whether ARs inject non-neutralized (net) electric currents in the solar atmosphere, responding to a debate initiated nearly two decades ago that remains inconclusive. We find that well-formed, intense magnetic polarity inversion lines (PILs) within ARs are the only photospheric magnetic structures that support significant net current. More intense PILs seem to imply stronger non-neutralized current patterns per polarity. This finding revises previous works that claim frequent injections of intense non-neutralized currents by most ARs appearing in the solar disk but also works that altogether rule out injection of non-neutralized currents. In agreement with previous studies, we also find that magnetically isolated ARs remain globally current-balanced. In addition, we confirm and quantify the preference of a given magnetic polarity to follow a given sense of electric currents, indicating a dominant sense of twist in ARs. This coherence effect is more pronounced in more compact ARs with stronger PILs and must be of sub-photospheric origin. Our results yield a natural explanation of the Lorentz force, invariably generating velocity and magnetic shear along strong PILs, thus setting a physical context for the observed pre-eruption evolution in solar ARs.

  6. Intrinsic connectivity of the rat subiculum: II. Properties of synchronous spontaneous activity and a demonstration of multiple generator regions.

    PubMed

    Harris, E; Stewart, M

    2001-07-01

    Brain structures that can generate epileptiform activity possess excitatory interconnections among principal cells and a subset of these neurons that can be spontaneously active ("pacemaker" cells). We describe electrophysiological evidence for excitatory interactions among rat subicular neurons. Subiculum was isolated from presubiculum, CA1, and entorhinal cortex in ventral horizontal slices. Nominally zero magnesium perfusate, picrotoxin (100 microM), or NMDA (20 microM) was used to induce spontaneous firing in subicular neurons. Synchronous population activity and the spread of population events from one end of subiculum to the other in isolated subicular subslices indicate that subicular pyramidal neurons are coupled together by excitatory synapses. Both electrophysiological classes of subicular pyramidal cells (bursting and regular spiking) exhibited synchronous activity, indicating that both cell classes are targets of local excitatory inputs. Burst firing neurons were active in the absence of synchronous activity in field recordings, indicating that these cells may serve as pacemaker neurons for the generation of epileptiform activity in subiculum. Epileptiform events could originate at either proximal or distal segments of the subiculum from ventral horizontal slices. In some slices, events originated in both proximal and distal locations and propagated to the other location. Finally, propagation was supported over axonal paths through the cell layer and in the apical dendritic zone. We conclude that subicular burst firing and regular spiking neurons are coupled by means of glutamatergic synapses. These connections may serve to distribute activity driven by topographically organized inputs and to synchronize subicular cell activity. PMID:11406829

  7. Evolution of Active Regions

    NASA Astrophysics Data System (ADS)

    van Driel-Gesztelyi, Lidia; Green, Lucie May

    2015-09-01

    The evolution of active regions (AR) from their emergence through their long decay process is of fundamental importance in solar physics. Since large-scale flux is generated by the deep-seated dynamo, the observed characteristics of flux emergence and that of the subsequent decay provide vital clues as well as boundary conditions for dynamo models. Throughout their evolution, ARs are centres of magnetic activity, with the level and type of activity phenomena being dependent on the evolutionary stage of the AR. As new flux emerges into a pre-existing magnetic environment, its evolution leads to re-configuration of small-and large-scale magnetic connectivities. The decay process of ARs spreads the once-concentrated magnetic flux over an ever-increasing area. Though most of the flux disappears through small-scale cancellation processes, it is the remnant of large-scale AR fields that is able to reverse the polarity of the poles and build up new polar fields. In this Living Review the emphasis is put on what we have learned from observations, which is put in the context of modelling and simulation efforts when interpreting them. For another, modelling-focused Living Review on the sub-surface evolution and emergence of magnetic flux see Fan (2009). In this first version we focus on the evolution of dominantly bipolar ARs.

  8. Active region seismology

    NASA Technical Reports Server (NTRS)

    Bogdan, Tom; Braun, D. C.

    1995-01-01

    Active region seismology is concerned with the determination and interpretation of the interaction of the solar acoustic oscillations with near-surface target structures, such as magnetic flux concentration, sunspots, and plage. Recent observations made with a high spatial resolution and a long temporal duration enabled measurements of the scattering matrix for sunspots and solar active regions to be carried out as a function of the mode properties. Based on this information, the amount of p-mode absorption, partial-wave phase shift, and mode mixing introduced by the sunspot, could be determined. In addition, the possibility of detecting the presence of completely submerged magnetic fields was raised, and new procedures for performing acoustic holography of the solar interior are being developed. The accumulating evidence points to the mode conversion of p-modes to various magneto-atmospheric waves within the magnetic flux concentration as being the unifying physical mechanism responsible for these diverse phenomena.

  9. Active region coronal evolution

    NASA Technical Reports Server (NTRS)

    Golub, L.; Noci, G.; Poletto, G.; Vaiana, G. S.

    1982-01-01

    Scaling relations between coronal base pressure and longitudinal photospheric magnetic field strength are tested for the case of a single active region observed for five solar rotations from Skylab. The evolution of measureable quantities, such as coronal thermal energy content, total longitudinal photospheric magnetic flux, region scale size, and peak energy density, is traced throughout the five rotations observed. The theoretically derived scaling law of Golub et al. (1980) is found to provide an acceptable fit to the data throughout the entire evolutionary history of the region from an age of about 3 days to the fully evolved state in which the mature active region merges into the general large-scale structure of the quiet corona. An alternative scaling law obtained by including the results of Galeev et al. (1981), however, is found to provide a somewhat better fit to the data. The study is seen as providing additional justification for the belief that magnetic field-related heating is the operative mechanism in the solar corona.

  10. Regional Activities Division. Papers.

    ERIC Educational Resources Information Center

    International Federation of Library Associations, The Hague (Netherlands).

    Papers on library network activities in Canada, the Third World, Japan, Malaysia, Brazil, and Sweden which were presented at the 1982 International Federation of Library Associations (IFLA) conference include: (1) "Canada: A Voluntary and Flexible Network," a review by Guy Sylvestre of the political, social, and economic structures affecting…

  11. Active droplet generation in microfluidics.

    PubMed

    Chong, Zhuang Zhi; Tan, Say Hwa; Gañán-Calvo, Alfonso M; Tor, Shu Beng; Loh, Ngiap Hiang; Nguyen, Nam-Trung

    2016-01-01

    The reliable generation of micron-sized droplets is an important process for various applications in droplet-based microfluidics. The generated droplets work as a self-contained reaction platform in droplet-based lab-on-a-chip systems. With the maturity of this platform technology, sophisticated and delicate control of the droplet generation process is needed to address increasingly complex applications. This review presents the state of the art of active droplet generation concepts, which are categorized according to the nature of the induced energy. At the liquid/liquid interface, an energy imbalance leads to instability and droplet breakup. PMID:26555381

  12. Active Region Release Two CMEs

    NASA Video Gallery

    Solar material can be seen blowing off the sun in this video captured by NASA’s Solar Dynamics Observatory (SDO) on the night of Feb. 5, 2013. This active region on the sun sent out two coronal ...

  13. Multithermal emission in active regions

    NASA Astrophysics Data System (ADS)

    Del Zanna, Giulio

    High-resolution EUV observations from SDO/AIA, Hi-C and Hinode/EIS are used, together with updated new atomic data, to study the multi-thermal emission in active region structures. Previous observations are largely confirmed, with most structures being not co-spatial and having nearly isothermal cross-sections. Those at temperatures below 1 MK appear as nearly resolved but those at 1-3 MK are still largely unresolved even at the Hi-C resolution. Very little emission above 3 MK is present in quiescent active regions. Elemental abundances vary in different structures. The active region cores show FIP enhancements of about a factor of three. X-ray spectroscopy confirms the results of the EUV observations for the hot cores.

  14. The Life Cycle of Active Region Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Cheung, M. C. M.; van Driel-Gesztelyi, L.; Martínez Pillet, V.; Thompson, M. J.

    2016-08-01

    We present a contemporary view of how solar active region magnetic fields are understood to be generated, transported and dispersed. Empirical trends of active region properties that guide model development are discussed. Physical principles considered important for active region evolution are introduced and advances in modeling are reviewed.

  15. SDO Sees Active Region Outbursts

    NASA Video Gallery

    This close up video by NASA’s Solar Dynamics Observatory shows an active region near the right-hand edge of the sun’s disk, which erupted with at least a dozen minor events over a 30-hour period fr...

  16. The 17 GHz active region number

    SciTech Connect

    Selhorst, C. L.; Pacini, A. A.; Costa, J. E. R.; Giménez de Castro, C. G.; Valio, A.; Shibasaki, K.

    2014-08-01

    We report the statistics of the number of active regions (NAR) observed at 17 GHz with the Nobeyama Radioheliograph between 1992, near the maximum of cycle 22, and 2013, which also includes the maximum of cycle 24, and we compare with other activity indexes. We find that NAR minima are shorter than those of the sunspot number (SSN) and radio flux at 10.7 cm (F10.7). This shorter NAR minima could reflect the presence of active regions generated by faint magnetic fields or spotless regions, which were a considerable fraction of the counted active regions. The ratio between the solar radio indexes F10.7/NAR shows a similar reduction during the two minima analyzed, which contrasts with the increase of the ratio of both radio indexes in relation to the SSN during the minimum of cycle 23-24. These results indicate that the radio indexes are more sensitive to weaker magnetic fields than those necessary to form sunspots, of the order of 1500 G. The analysis of the monthly averages of the active region brightness temperatures shows that its long-term variation mimics the solar cycle; however, due to the gyro-resonance emission, a great number of intense spikes are observed in the maximum temperature study. The decrease in the number of these spikes is also evident during the current cycle 24, a consequence of the sunspot magnetic field weakening in the last few years.

  17. Global oscillations and active regions

    NASA Astrophysics Data System (ADS)

    Durrant, C. J.

    The author presents further estimates of the amplitude of the modulation of the solar global velocity signal caused by the passage of active regions across the solar disc. Using measurements of the profile of the K I λ769.9 nm line in the quiet sun and in plages he finds a global velocity variation of ≡2 m s-1 during the transit of a typical active region of area 3300 millionths of the hemisphere. However, during the period in which a velocity amplitude of 6 m s-1 was reported by Claverie et al. (1982), the sunspot areas were exceptionally large and the author confirms Schröter's (1984) result that the combination of spot and plage contributions is sufficient to account for the observed signal. The velocity modulation is thus attributable to surface inhomogeneities, not to the structure of the solar core.

  18. Wave activated power generation system

    SciTech Connect

    Ono, Y.

    1983-08-09

    A wave activated power generation system of the float type is disclosed, comprising at least one piston-cylinder device having an anchored cylinder and a piston slidable in the cylinder and cooperating with the cylinder to form a pumping chamber above the piston and a low pressure chamber below the piston. The cylinder has an intake port and an exhaust port both formed at an upper port thereof to communicate with the pumping chamber and each provided with a check valve. A float is connected through a cable to the piston of the piston- cylinder device. A pair of fluid storages are connected to the intake port and the exhaust port of the pumping chamber, respectively. A waterwheel generator is driven by the fluid flowing from one of the fluid storages to another. A pressure regulating device is connected to the low pressure chamber so as to maintain the low pressure chamber at a pressure lower than the pressure in the pumping chamber, the difference in pressure ceaselessly applying a downward force on the piston to keep the cable in a tensed condition.

  19. Approaches for the Detection of Microseism Generating Regions from Space

    NASA Astrophysics Data System (ADS)

    Rodriguez, E.; Kedar, S.

    2004-12-01

    Ocean microseisms have been suggested as a potential source for tomographic imaging of the Earth. An optimal tomographic approach requires that the source regions for ocean microseism generation be known. Longuet-Higgins (Philos. trans. R. Soc. London, 1950) has suggested that standing waves in the ocean are responsible for the generation of microseisms, so that a potential way of determining the regions responsible for microseism generation is the determination of which regions of the ocean exhibit standing wave activity. Although ocean standing waves have been observed and modeled in a laboratory setting, there is currently no remote sensing instrument capable of providing direct observations. In this paper, we consider remote sensing or modeling measurements which might provide observations indicative of potential standing wave activity. The first option, radar altimetry, provides a measurement of the significant wave height and, at lower resolutions, sea surface skewness. It is expected that non-linear interactions will result in a spatial modulation of the wave field and an increase of surface skewness. We review the accuracy of current ocean altimeters and conclude that, while these type of observations might be possible in the future, current altimeters do not have sufficient accuracy to retrieve the expected signals. An alternate approach is to use wave directional spectra to estimate the standing wave energy which might be observed. There are two potential sources for the estimation of directional wave spectra: wave action models (WAM's) or synthetic aperture radar (SAR). We review the capabilities of each of these measurements and conclude that they present a useful potential source for estimating regions of microseism generation. To test this conclusion, we present results of comparisons between SAR data collected off the California and WAM data with seismic data.

  20. Cometary nucleus and active regions

    NASA Technical Reports Server (NTRS)

    Whipple, F. L.

    1984-01-01

    On the basis of the icy conglomerate model of cometary nuclei, various observations demonstrate the spotted nature of many or most nuclei, i.e., regions of unusual activity, either high or low. Rotation periods, spin axes and even precession of the axes are determined. The observational evidence for variations in activity over the surfaces of cometary nuclei are listed and discussed. On June 11 the comet IRAS-ARAKI-ALCOCK approached the Earth to a distance of 0.031 AU, the nearest since C/Lexell, 1770 I, providing a unique opportunity for near-nucleus observations. Preliminary analysis of these images establishes the spin axis of the nucleus, with an oblioquity to the orbit plane of approximately 50 deg, and a lag angle of sublimation approximately 35 deg from the solar meridian on the nucleus. Asymmetries of the inner coma suggests a crazy-quilt distribution of ices with differing volatility over the surface of the nucleus. The observations of Comet P/Homes 1892 III, exhibiting two 8-10 magnitude bursts, are carefully analyzed. The grazing encounter produced, besides the first great burst, an active area on the nucleus, which was rotating retrograde with a period of 16.3hr and inclination nearly 180 deg. After the first burst the total magnitude fell less than two magnitudes from November 7 to November 30 (barely naked eye) while the nuclear region remained diffuse or complex, rarely if ever showing a stellar appearance. The fading was much more rapid after the second burst. The grazing encounter distributed a volume of large chunks in the neighborhood of the nucleus, maintaining activity for weeks.

  1. Volcanically Active Regions on Io

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Shown here is a portion of one of the highest-resolution images of Io (Latitude: +10 to +60 degrees, Longitude: 180 to 225 degrees) acquired by the Galileo spacecraft, revealing immense lava flows and other volcanic landforms. Several high-temperature volcanic hot spots have been detected in this region by both the Near Infrared Mapping Spectrometer and the imaging system of Galileo. The temperatures are consistent with active silicate volcanism in lava flows or lava lakes (which reside inside irregular depressions called calderas). The large dark lava flow in the upper left region of the image is more than 400 km long, similar to ancient flood basalts on Earth and mare lavas on the Moon.

    North is to the top of the picture and the sun illuminates the surface from the left. The image covers an area 1230 kilometers wide and the smallest features that can be discerned are 2.5 kilometers in size. This image was taken on November 6th, 1996, at a range of 245,719 kilometers by the Solid State Imaging (CCD) system on the Galileo Spacecraft.

    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 Galileo mission home page on the World Wide Web at 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

  2. Emerging flux in active regions. [of sun

    NASA Technical Reports Server (NTRS)

    Liggett, M.; Zirin, H.

    1985-01-01

    The rates at which flux emerges in active and quiet solar regions within the sunspot belts are compared. The emerging flux regions (EFRs) were identified by the appearance of arch filament structures in H-alpha. All EFRs in high resolution films of active regions made at Big Bear in 1978 were counted. The comparable rate of flux emergence in quiet regions was obtained from SGD data and independently from EFRs detected outside the active region perimeter on the same films. The rate of flux emergence is 10 times higher in active regions than in quiet regions. A sample of all active regions in 31 days of 1983 gave a ratio of 7.5. Possible mechanisms which might funnel new magnetic flux to regions of strong magnetic field are discussed.

  3. Emission measure distribution for diffuse regions in solar active regions

    SciTech Connect

    Subramanian, Srividya; Tripathi, Durgesh; Klimchuk, James A.; Mason, Helen E.

    2014-11-01

    Our knowledge of the diffuse emission that encompasses active regions is very limited. In this paper we investigate two off-limb active regions, namely, AR 10939 and AR 10961, to probe the underlying heating mechanisms. For this purpose, we have used spectral observations from Hinode/EIS and employed the emission measure (EM) technique to obtain the thermal structure of these diffuse regions. Our results show that the characteristic EM distributions of the diffuse emission regions peak at log T = 6.25 and the coolward slopes are in the range 1.4-3.3. This suggests that both low- as well as high-frequency nanoflare heating events are at work. Our results provide additional constraints on the properties of these diffuse emission regions and their contribution to the background/foreground when active region cores are observed on-disk.

  4. Renewable Generation Effect on Net Regional Energy Interchange: Preprint

    SciTech Connect

    Diakov, Victor; Brinkman, Gregory; Denholm, Paul; Jenkin, Thomas; Margolis, Robert

    2015-07-30

    Using production-cost model (PLEXOS), we simulate the Western Interchange (WECC) at several levels of the yearly renewable energy (RE) generation, between 13% and 40% of the total load for the year. We look at the overall energy exchange between a region and the rest of the system (net interchange, NI), and find it useful to examine separately (i) (time-)variable and (ii) year-average components of the NI. Both contribute to inter-regional energy exchange, and are affected by wind and PV generation in the system. We find that net load variability (in relatively large portions of WECC) is the leading factor affecting the variable component of inter-regional energy exchange, and the effect is quantifiable: higher regional net load correlation with the rest of the WECC lowers net interchange variability. Further, as the power mix significantly varies between WECC regions, effects of ‘flexibility import’ (regions ‘borrow’ ramping capability) are also observed.

  5. The Main Sequence of Explosive Solar Active Regions: Comparison of Emerging and Mature Active Regions

    NASA Technical Reports Server (NTRS)

    Falconer, David; Moore, Ron

    2011-01-01

    For mature active regions, an active region s magnetic flux content determines the maximum free energy the active region can have. Most Large flares and CMEs occur in active regions that are near their free-energy limit. Active-region flare power radiated in the GOES 1-8 band increases steeply as the free-energy limit is approached. We infer that the free-energy limit is set by the rate of release of an active region s free magnetic energy by flares, CMEs and coronal heating balancing the maximum rate the Sun can put free energy into the active region s magnetic field. This balance of maximum power results in explosive active regions residing in a "mainsequence" in active-region (flux content, free energy content) phase space, which sequence is analogous to the main sequence of hydrogen-burning stars in (mass, luminosity) phase space.

  6. The Twist Limit for Bipolar Active Regions

    NASA Technical Reports Server (NTRS)

    Moore, Ron; Falconer, David; Gary, Allen

    2008-01-01

    We present new evidence that further supports the standard idea that active regions are emerged magnetic-flux-rope omega loops. When the axial magnetic twist of a cylindrical flux rope exceeds a critical amount, the flux rope becomes unstable to kinking, and the excess axial twist is converted into writhe twist by the kinking. This suggests that, if active regions are emerged omega loops, then (1) no active region should have magnetic twist much above the limit set by kinking, (2) active regions having twist near the limit should often arise from kinked omega loops, and (3) since active regions having large delta sunspots are outstandingly twisted, these arise from kinked omega loops and should have twist near the limit for kinking. From each of 36 vector magnetograms of bipolar active regions, we have measured (1) the total flux of the vertical field above 100 G, (2) the area covered by this flux, and (3) the net electric current that arches over the polarity inversion line. These three quantities yield an estimate of the axial magnetic twist in a simple model cylindrical flux rope that corresponds to the top of the active region s hypothetical omega loop prior to emergence. In all 36 cases, the estimated twist is below the critical limit for kinking. The 11 most twisted active regions (1) have estimated twist within a factor of approx.3 of the limit, and (2) include all of our 6 active regions having large delta sunspots. Thus, our observed twist limit for bipolar active regions is in good accord with active regions being emerged omega loops.

  7. Generation and Suppression of E Region Artificial Field Aligned Irregularities

    NASA Astrophysics Data System (ADS)

    Miceli, R. J.; Hysell, D. L.; Munk, J.; Han, S.

    2012-12-01

    Artificial field-aligned plasma density irregularities (FAIs) were generated in the E region of the ionosphere above the High Frequency Active Auroral Research Program (HAARP) facility during campaigns in May and August of 2012 and were quantified using a 30 MHz coherent scatter radar in Homer, Alaska. The purpose of the experiment was to analyze the X-mode suppression of FAIs generated from O-mode heating and to measure the threshold required to excite thermal parametric instabilities. The irregularities were excited by gradually increasing the power of a zenith pointing O-mode emission transmitted at a frequency of 2.75 MHz. To suppress the irregularities, a second X-mode emission at a higher frequency was added on alternating power cycles. The Homer radar measured the signal-to-noise ratio, Doppler shift, and spectral width of echoes reflected from the irregularities. We will calculate the threshold electric field required to excite the irregularities and compare with similar experiments in order to better understand the thermal parametric instability.

  8. Software Displays Data on Active Regions of the Sun

    NASA Technical Reports Server (NTRS)

    Golightly, Mike; Weyland, Mark; Raben, Vern

    2011-01-01

    The Solar Active Region Display System is a computer program that generates, in near real time, a graphical display of parameters indicative of the spatial and temporal variations of activity on the Sun. These parameters include histories and distributions of solar flares, active region growth, coronal mass ejections, size, and magnetic configuration. By presenting solar-activity data in graphical form, this program accelerates, facilitates, and partly automates what had previously been a time-consuming mental process of interpretation of solar-activity data presented in tabular and textual formats. Intended for original use in predicting space weather in order to minimize the exposure of astronauts to ionizing radiation, the program might also be useful on Earth for predicting solar-wind-induced ionospheric effects, electric currents, and potentials that could affect radio-communication systems, navigation systems, pipelines, and long electric-power lines. Raw data for the display are obtained automatically from the Space Environment Center (SEC) of the National Oceanic and Atmospheric Administration (NOAA). Other data must be obtained from the NOAA SEC by verbal communication and entered manually. The Solar Active Region Display System automatically accounts for the latitude dependence of the rate of rotation of the Sun, by use of a mathematical model that is corrected with NOAA SEC active-region position data once every 24 hours. The display includes the date, time, and an image of the Sun in H light overlaid with latitude and longitude coordinate lines, dots that mark locations of active regions identified by NOAA, identifying numbers assigned by NOAA to such regions, and solar-region visual summary (SRVS) indicators associated with some of the active regions. Each SRVS indicator is a small pie chart containing five equal sectors, each of which is color-coded to provide a semiquantitative indication of the degree of hazard posed by one aspect of the activity at

  9. Model-based automatic generation of grasping regions

    NASA Technical Reports Server (NTRS)

    Bloss, David A.

    1993-01-01

    The problem of automatically generating stable regions for a robotic end effector on a target object, given a model of the end effector and the object is discussed. In order to generate grasping regions, an initial valid grasp transformation from the end effector to the object is obtained based on form closure requirements, and appropriate rotational and translational symmetries are associated with that transformation in order to construct a valid, continuous grasping region. The main result of this algorithm is a list of specific, valid grasp transformations of the end effector to the target object, and the appropriate combinations of translational and rotational symmetries associated with each specific transformation in order to produce a continuous grasp region.

  10. Neutronics activities for next generation devices

    SciTech Connect

    Gohar, Y.

    1985-01-01

    Neutronic activities for the next generation devices are the subject of this paper. The main activities include TFCX and FPD blanket/shield studies, neutronic aspects of ETR/INTOR critical issues, and neutronics computational modules for the tokamak system code and tandem mirror reactor system code. Trade-off analyses, optimization studies, design problem investigations and computational models development for reactor parametric studies carried out for these activities are summarized.

  11. 3D MHD Models of Active Region Loops

    NASA Technical Reports Server (NTRS)

    Ofman, Leon

    2004-01-01

    Present imaging and spectroscopic observations of active region loops allow to determine many physical parameters of the coronal loops, such as the density, temperature, velocity of flows in loops, and the magnetic field. However, due to projection effects many of these parameters remain ambiguous. Three dimensional imaging in EUV by the STEREO spacecraft will help to resolve the projection ambiguities, and the observations could be used to setup 3D MHD models of active region loops to study the dynamics and stability of active regions. Here the results of 3D MHD models of active region loops are presented, and the progress towards more realistic 3D MHD models of active regions. In particular the effects of impulsive events on the excitation of active region loop oscillations, and the generation, propagations and reflection of EIT waves are shown. It is shown how 3D MHD models together with 3D EUV observations can be used as a diagnostic tool for active region loop physical parameters, and to advance the science of the sources of solar coronal activity.

  12. Active Region Emergence and Remote Flares

    NASA Astrophysics Data System (ADS)

    Fu, Yixing; Welsch, Brian T.

    2016-02-01

    We study the effect of new emerging solar active regions on the large-scale magnetic environment of existing regions. We first present a theoretical approach to quantify the "interaction energy" between new and pre-existing regions as the difference between i) the summed magnetic energies of their individual potential fields and ii) the energy of their superposed potential fields. We expect that this interaction energy can, depending upon the relative arrangements of newly emerged and pre-existing magnetic flux, indicate the existence of "topological" free magnetic energy in the global coronal field that is independent of any "internal" free magnetic energy due to coronal electric currents flowing within the newly emerged and pre-existing flux systems. We then examine the interaction energy in two well-studied cases of flux emergence, but find that the predicted energetic perturbation is relatively small compared to energies released in large solar flares. Next, we present an observational study of the influence of the emergence of new active regions on flare statistics in pre-existing active regions, using NOAA's Solar Region Summary and GOES flare databases. As part of an effort to precisely determine the emergence time of active regions in a large event sample, we find that emergence in about half of these regions exhibits a two-stage behavior, with an initial gradual phase followed by a more rapid phase. Regarding flaring, we find that the emergence of new regions is associated with a significant increase in the occurrence rate of X- and M-class flares in pre-existing regions. This effect tends to be more significant when pre-existing and new emerging active regions are closer. Given the relative weakness of the interaction energy, this effect suggests that perturbations in the large-scale magnetic field, such as topology changes invoked in the "breakout" model of coronal mass ejections, might play a significant role in the occurrence of some flares.

  13. Hinode Captures Images of Solar Active Region

    NASA Video Gallery

    In these images, Hinode's Solar Optical Telescope (SOT) zoomed in on AR 11263 on August 4, 2011, five days before the active region produced the largest flare of this cycle, an X6.9. We show images...

  14. The flare productivity of active regions

    NASA Astrophysics Data System (ADS)

    Kuroda, N.; Christe, S.

    2012-12-01

    Previous studies have shown that the flare frequency distribution is consistent with a power-law. Furthermore, studies have shown that regions of higher magnetic complexity produce more large flares. This may imply that the flare frequency distribution is harder for magnetically complex active regions. However, the relationship between source active regions' magnetic complexity and the flare size distribution has not been extensively studied. We present a new study of 25,000 microflares detected by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) from March 2002 to February 2007. For each flare, we have obtained the two classifications of magnetic complexity, the Mount Wilson Magnetic Classification and the Zurich/McIntosh Sunspot Classification, from the Solar Region Summary prepared by the National Oceanic and Atmospheric Administration (NOAA)/ Space Weather Prediction Center (SWPC), and compared them with the RHESSI flare size distribution as observed in the 12 to 25 keV energy range. We investigate the relationship between the slope of the microflare size distribution and the magnetic properties of source active regions. For each flare we obtain the relevant MDI magnetogram to determine properties such as the area of the source active region and total unsigned magnetic flux. These properties are then compared to properties of the associated microflares such as peak flux and microflare size distribution. We find that, for both the Mount Wilson Magnetic Classification and the Zurich/McIntosh Sunspot Classification, the slopes of the microflare size distribution tend to get harder as a function of magnetic complexity. For example, in Mount Wilson Magnetic Classification the slope for α regions was 1.66 and the slope for βγδ region was 1.51.This suggests that βγδ regions are 50 % more likely to produce X class flares than α regions.

  15. Chromospheric Acoustic Oscillations in Active Flaring Regions

    NASA Astrophysics Data System (ADS)

    Monsue, T.; Hill, F.; Stassun, K.

    2014-12-01

    Chromospheric p-mode oscillations are studied in Hα to obtain helioseismic information regarding the local structural conditions around highly magnetic regions such as sunspots. Solar flares commonly occur in active regions where these sunspots exist therefore boosting the p-mode power. In our current study of analyzing p-modes in the chromosphere we study the time evolution of acoustic p-mode oscillation data taken from the Global Oscillation Network Group (GONG) Hα, and investigate the p-modes across the frequency band (1 < ν < 8.33 mHz). This study entails three active regions directly over sunspots, with accompanying flaring activity from two solar flares, occurring on June 13th and July 12th, 2012. Our analysis utilizes time series data to create Fourier power spectra of individual pixels spatially resolved around the flare region, to study the frequency bands. We then study how the frequency distribution evolves temporally by constructing a Power Map Movie (PMM) of the regions. From these PMMs we can take a survey of the chromospheric oscillations for each frequency band. We found that the intensity of the flare has an effect on the behavior of the p-modes within different frequency bands. The suppression of power was observed in dark anomalous structures within the PMMs and in other regions there was an observed boost in power due to flaring activity.

  16. Growth and Decay of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Dobias, J. J.; Chapman, G. A.; Cookson, A. M.; Preminger, D. G.; Walton, S. R.

    2002-05-01

    We report here on a study of growth and decay rates of sunspot and facular areas of solar active regions. The data used in this project come from an ongoing program of daily photometric observations of the sun with the Cartesian Full Disk Telescope No. 1 (CFDT1) at the San Fernando Observatory (SFO). Sunspot regions are determined from images taken with a red filter centered at 672.3 nm with a bandpass of 9.7 nm, while images taken with a Ca II K line filter, centered at 393.4 nm and with a bandpass of only 1nm, are used to find facular areas. Before any areas can be found on any observed images, they have to be calibrated then flattened by removing limb darkening thus producing contrast images. Sunspot areas are then determined from any pixel with contrast of -8.5% or less, while any pixel on a K line contrast image with a contrast of +4.8%/μ or higher, where μ is the cosine of the heliocentric angle, is considered to be a facular pixel. To identify the areas as clearly as possible, studied active regions were usually observed on the sun with relatively low activity; that means that each region is either alone on the sun's disk or with only very few other active regions present. Furthermore, to obtain growth and decay patterns of the areas as reliably as possible, only such active regions must be chosen for which there is as complete observational coverage as possible. At the present time studies have been finished for only a few active regions, but analysis of several others is on going. Obtained results will be presented at the meeting. This work is supported by NSF grant ATM-9912132 and NASA grants NAG5-7191 and NAG5-7778.

  17. Face Generation Using Emotional Regions for Sensibility Robot

    NASA Astrophysics Data System (ADS)

    Gotoh, Minori; Kanoh, Masayoshi; Kato, Shohei; Kunitachi, Tsutomu; Itoh, Hidenori

    We think that psychological interaction is necessary for smooth communication between robots and people. One way to psychologically interact with others is through facial expressions. Facial expressions are very important for communication because they show true emotions and feelings. The ``Ifbot'' robot communicates with people by considering its own ``emotions''. Ifbot has many facial expressions to communicate enjoyment. We developed a method for generating facial expressions based on human subjective judgements mapping Ifbot's facial expressions to its emotions. We first created Ifbot's emotional space to map its facial expressions. We applied a five-layer auto-associative neural network to the space. We then subjectively evaluated the emotional space and created emotional regions based on the results. We generated emotive facial expressions using the emotional regions.

  18. The Magnetic Free Energy in Active Regions

    NASA Technical Reports Server (NTRS)

    Metcalf, Thomas R.; Mickey, Donald L.; LaBonte, Barry J.

    2001-01-01

    The magnetic field permeating the solar atmosphere governs much of the structure, morphology, brightness, and dynamics observed on the Sun. The magnetic field, especially in active regions, is thought to provide the power for energetic events in the solar corona, such as solar flares and Coronal Mass Ejections (CME) and is believed to energize the hot coronal plasma seen in extreme ultraviolet or X-rays. The question remains what specific aspect of the magnetic flux governs the observed variability. To directly understand the role of the magnetic field in energizing the solar corona, it is necessary to measure the free magnetic energy available in active regions. The grant now expiring has demonstrated a new and valuable technique for observing the magnetic free energy in active regions as a function of time.

  19. Fluxon Modeling of Active Region Evolution

    NASA Astrophysics Data System (ADS)

    Deforest, C. E.; Kankelborg, C. C.; Davey, A. R.; Rachmeler, L.

    2006-12-01

    We present current results and status on fluxon modeling of free energy buildup and release in active regions. Our publicly available code, FLUX, has the unique ability to track magnetic energy buildup with a truly constrained topology in evolving, nonlinear force-free conditions. Recent work includes validation of the model against Low &Lou force-free field solutions, initial evolution studies of idealized active regions, and inclusion of locally parameterized reconnection into the model. FLUX is uniquely able to simulate complete active regions in 3-D on a single workstation; we estimate that a parallelized fluxon model, together with computer vision code to ingest solar data, could run faster than real time on a cluster of \\textasciitilde 30 CPUs and hence provide a true predictive space weather model in the style of predictive simulations of terrestrial weather.

  20. Overview of Meteosat Third Generation (MTG) Activities

    NASA Astrophysics Data System (ADS)

    Bensi, P.; Aminou, D.; Bézy, J.-L.; Stuhlmann, R.; Rodriguez, A.; Tjemkes, S.

    2004-11-01

    Following the successful commissioning of the first satellite of the Meteosat Second Generation (MSG) series and its operational deployment in January 2004 as Meteosat-8, EUMETSAT and the European Space Agency (ESA) are actively preparing the Meteosat Third Generation (MTG) mission to provide a future operational geostationary meteorological satellite system in the post 2015 time frame. This paper provides an overview of the MTG user consultation process, from the definition of the user needs up to the selection of mission concepts to be defined in the frame of dedicated system architecture studies carried out by ESA at pre-phase A level.

  1. DTM generation in forest regions from satellite stereo imagery

    NASA Astrophysics Data System (ADS)

    Tian, J.; Krauss, T.; Reinartz, P.

    2014-11-01

    Satellite stereo imagery is becoming a popular data source for derivation of height information. Many new Digital Surface Model (DSM) generation and evaluation methods have been proposed based on these data. A novel Digital Terrain Model (DTM) extraction method based on the DSM from satellite stereo imagery is proposed in this paper. Instead of directly filtering the DSM, firstly a single channel based classification method is proposed. In this step, no multi-spectral information is used, because for some stereo sensors, like Cartosat-1, only panchromatic channels are available. The proposed classification method adopts the random forests method to get initial probability maps of the four main classes in forest regions (high-forest, low-forest, ground, and buildings). To cover the pepper and salt effect of this pixel based classification method, the probability maps are further filtered based on the adaptive Wiener filtering. Then a cube-based greedy strategy is applied in generating the final classification map from these refined probability maps. Secondly, the height distances between neighboring regions are calculated along the boundary regions. These height distances can be used to estimate the relative region heights. Thirdly, the DTM is extracted by subtracting these relative region heights from the DSM in the order of: buildings - low forest - high forest. In the end, the extracted DTM is further smoothed using median filter. The proposed DTM extraction method is finally tested on satellite stereo imagery captured by Cartosat-1. Quality evaluation is performed by comparing the extracted DTMs to a reference DTM, which is generated from the last return airborne laser scanning point cloud.

  2. Quantifying the Complexity of Flaring Active Regions

    NASA Astrophysics Data System (ADS)

    Stark, B.; Hagyard, M. J.

    1997-05-01

    While solar physicists have a better understanding of the importance magnetic fields play in the solar heating mechanism, it is still not possible to predict whether or when an active region will flare. In recent decades, qualitative studies of the changes in active region morphology have shown that there is generally an increase in the complexity of the spatial configuration of a solar active region leading up to a flare event. In this study, we quantify the spatial structure of the region using the Differential Box-Counting Method (DBC)of fractal analysis. We analyze data from NASA/Marshall Space Flight Center's vector magnetograph from two flaring active regions: AR 6089 from June 10, 1990, which produced one M1.7 flare, and AR 6659 from June 8, 9 and 10, 1991, this data set including one C5.7 and two M(6.4 and 3.2) flares. (AR 6659 produced several other flares). Several magnetic parameters are studied, including the transverse and longitudinal magnetic field components (Bt and Bl), the total field (Bmag), and the magnetic shear, which describes the non-potentiality of the field. Results are presented for the time series of magnetograms in relation to the timing of flare events.

  3. Quantifying the Complexity of Flaring Active Regions

    NASA Technical Reports Server (NTRS)

    Stark, B.; Hagyard, M. J.

    1997-01-01

    While solar physicists have a better understanding of the importance magnetic fields play in the solar heating mechanism, it is still not possible to predict whether or when an active region will flare. In recent decades, qualitative studies of the changes in active region morphology have shown that there is generally an increase in the complexity of the spatial configuration of a solar active region leading up to a flare event. In this study, we quantify the spatial structure of the region using the differential Box-Counting Method (DBC) of fractal analysis. We analyze data from NASA/Marshall Space Flight Centr's vector magnetograph from two flaring active regions: AR 6089 from June 10, 1990, which produced one M1.7 flare, and AR 6659 from June 8, 9 and 10, 1991, this data set including one C5.7 and two M(6.4 and 3.2) flare. (AR 6659 produced several other flares). Several magnetic parameters are studied, including the transverse and longitudinal magnetic field components (Bt and B1), the total field (Bmag), and the magnetic shear, which describes the non-potentiality of the field. Results are presented for the time series of magnetograms in relation to the timing of flare events.

  4. Generativity as a Route to Active Ageing

    PubMed Central

    Kruse, Andreas; Schmitt, Eric

    2012-01-01

    We elucidate the significance of active ageing from an individual as well as from a societal perspective. Taking an individual perspective, maintaining activity in later years is linked to successful ageing because of empirical relationships to positive self-perception, satisfaction with life, and development of competences, whereas from a societal perspective, active ageing implies usage of older people's life competences as a human capital of society—a societal imperative, particularly in times of demographic change but also more basically substantiated in an ethics of responsibility, intergenerational solidarity, and generation equity. We focus on the psychological construct of generativity which is interpreted as an aspect of the philosophical-anthropological category of joint responsibility. Our own research in Mexico and the Baltic States supports the notion that maintaining access to the public sphere and active engagement for others is a more basic individual concern than a life-stages specific developmental task. We report background and results of a Dialogue Forum Project Funding, a research cooperation between our institute and the Foundation Remembrance, Responsibility, and Future aimed to improve generativity in Belarus, Russia, and Ukraine by implementing and supporting local initiatives offering opportunities for intergenerational dialogue. PMID:22919378

  5. ON THE FORMATION OF ACTIVE REGIONS

    SciTech Connect

    Stein, Robert F.; Nordlund, Ake E-mail: aake@nbi.dk

    2012-07-01

    Magnetoconvection can produce an active region without an initial coherent flux tube. A simulation was performed where a uniform, untwisted, horizontal magnetic field of 1 kG strength was advected into the bottom of a computational domain 48 Mm wide by 20 Mm deep. The up and down convective motions produce a hierarchy of magnetic loops with a wide range of scales, with smaller loops riding 'piggy-back' in a serpentine fashion on larger loops. When a large loop approaches the surface, it produces a small active region with a compact leading spot and more diffuse following spots.

  6. On the Formation of Active Regions

    NASA Astrophysics Data System (ADS)

    Stein, Robert F.; Nordlund, Åke

    2012-07-01

    Magnetoconvection can produce an active region without an initial coherent flux tube. A simulation was performed where a uniform, untwisted, horizontal magnetic field of 1 kG strength was advected into the bottom of a computational domain 48 Mm wide by 20 Mm deep. The up and down convective motions produce a hierarchy of magnetic loops with a wide range of scales, with smaller loops riding "piggy-back" in a serpentine fashion on larger loops. When a large loop approaches the surface, it produces a small active region with a compact leading spot and more diffuse following spots.

  7. On the Spectrum and Generation Regions of Solar Microbursts in the Decimeter Wave Band

    NASA Astrophysics Data System (ADS)

    Yasnov, L. V.; Gofman, A. A.; Stupishin, A. G.

    2016-08-01

    We analyze the nature and physical conditions in the generation regions of decimeter microbursts (MBs), which were discovered with the radiotelescope of the Russian Academy of Sciences (RATAN-600). One of the main peculiarities of MBs is an almost constant upper-frequency limit of about 1.1 GHz, which has not been explained in previously studied generation models. Here it is shown that this spectral peculiarity can be explained by the generation of the upper-hybrid waves at the double plasma resonance (DPR) and a subsequent transformation into low-frequency plasma waves considering free-free and cyclotron absorption. Model calculations show that MBs occur in the active regions where the magnetic-field strength is close to 100 G. MBs are most probably generated in the transition region of the solar atmosphere between main magnetic fields with opposite polarities.

  8. On the Spectrum and Generation Regions of Solar Microbursts in the Decimeter Wave Band

    NASA Astrophysics Data System (ADS)

    Yasnov, L. V.; Gofman, A. A.; Stupishin, A. G.

    2016-07-01

    We analyze the nature and physical conditions in the generation regions of decimeter microbursts (MBs), which were discovered with the radiotelescope of the Russian Academy of Sciences (RATAN-600). One of the main peculiarities of MBs is an almost constant upper-frequency limit of about 1.1 GHz, which has not been explained in previously studied generation models. Here it is shown that this spectral peculiarity can be explained by the generation of the upper-hybrid waves at the double plasma resonance (DPR) and a subsequent transformation into low-frequency plasma waves considering free-free and cyclotron absorption. Model calculations show that MBs occur in the active regions where the magnetic-field strength is close to 100 G. MBs are most probably generated in the transition region of the solar atmosphere between main magnetic fields with opposite polarities.

  9. Solar Eruptions Initiated in Sigmoidal Active Regions

    NASA Astrophysics Data System (ADS)

    Savcheva, Antonia

    2016-07-01

    active regions that have been shown to possess high probability for eruption. They present a direct evidence of the existence of flux ropes in the corona prior to the impulsive phase of eruptions. In order to gain insight into their eruptive behavior and how they get destabilized we need to know their 3D magnetic field structure. First, we review some recent observations and modeling of sigmoidal active regions as the primary hosts of solar eruptions, which can also be used as useful laboratories for studying these phenomena. Then, we concentrate on the analysis of observations and highly data-constrained non-linear force-free field (NLFFF) models over the lifetime of several sigmoidal active regions, where we have captured their magnetic field structure around the times of major flares. We present the topology analysis of a couple of sigmoidal regions pointing us to the probable sites of reconnection. A scenario for eruption is put forward by this analysis. We demonstrate the use of this topology analysis to reconcile the observed eruption features with the standard flare model. Finally, we show a glimpse of how such a NLFFF model of an erupting region can be used to initiate a CME in a global MHD code in an unprecedented realistic manner. Such simulations can show the effects of solar transients on the near-Earth environment and solar system space weather.

  10. Asia Section. Regional Activities Division. Paper.

    ERIC Educational Resources Information Center

    International Federation of Library Associations, The Hague (Netherlands).

    Two papers on library and information activities in developing nations, particularly in India and other Asian countries, were presented at the 1983 International Federation of Library Associations (IFLA) conference. In "IFLA in Asia: A Review of the Work of the Regional Section for Asia," Edward Lim Huck Tee (Malaysia) describes the low level of…

  11. Swim pressure: stress generation in active matter.

    PubMed

    Takatori, S C; Yan, W; Brady, J F

    2014-07-11

    We discover a new contribution to the pressure (or stress) exerted by a suspension of self-propelled bodies. Through their self-motion, all active matter systems generate a unique swim pressure that is entirely athermal in origin. The origin of the swim pressure is based upon the notion that an active body would swim away in space unless confined by boundaries-this confinement pressure is precisely the swim pressure. Here we give the micromechanical basis for the swim stress and use this new perspective to study self-assembly and phase separation in active soft matter. The swim pressure gives rise to a nonequilibrium equation of state for active matter with pressure-volume phase diagrams that resemble a van der Waals loop from equilibrium gas-liquid coexistence. Theoretical predictions are corroborated by Brownian dynamics simulations. Our new swim stress perspective can help analyze and exploit a wide class of active soft matter, from swimming bacteria to catalytic nanobots to molecular motors that activate the cellular cytoskeleton. PMID:25062240

  12. Magnetic helicity in emerging solar active regions

    SciTech Connect

    Liu, Y.; Hoeksema, J. T.; Bobra, M.; Hayashi, K.; Sun, X.; Schuck, P. W.

    2014-04-10

    Using vector magnetic field data from the Helioseismic and Magnetic Imager instrument aboard the Solar Dynamics Observatory, we study magnetic helicity injection into the corona in emerging active regions (ARs) and examine the hemispheric helicity rule. In every region studied, photospheric shearing motion contributes most of the helicity accumulated in the corona. In a sample of 28 emerging ARs, 17 follow the hemisphere rule (61% ± 18% at a 95% confidence interval). Magnetic helicity and twist in 25 ARs (89% ± 11%) have the same sign. The maximum magnetic twist, which depends on the size of an AR, is inferred in a sample of 23 emerging ARs with a bipolar magnetic field configuration.

  13. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, Anthony M.

    1998-06-02

    A method for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors.

  14. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, Anthony M.

    1996-01-01

    A method for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors.

  15. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, A.M.

    1998-06-02

    A method is disclosed for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors. 10 figs.

  16. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, A.M.

    1996-01-30

    A method is disclosed for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors. 10 figs.

  17. Supergranule Diffusion and Active Region Decay

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.; Choudhary, Debi Prasad

    2004-01-01

    Models of the Sun's magnetic dynamo include turbulent diffusion to parameterize the effects of convective motions on the evolution of the Sun's magnetic field. Supergranules are known to dominate the evolution of the surface magnetic field structure as evidenced by the structure of both the active and quiet magnetic network. However, estimates for the dif hivity attributed to su perymules differ by an order of magnitude from about 100 km sup2/s to more than 1000 km sup2/s. We examine this question of the e i v i t y using three merent approaches. 1) We study the decay of more than 30,000 active regions by determining the rate of change in the sunspot area of each active region from day-to-day. 2) We study the decay of a single isolated active region near the time of solar minimum by examining the magnetic field evolution over five solar rotations fiom SOHOMDI magnetograms obtained at 96-minute intervals. 3) We study the characteristics of supergranules that influence the estimates of their diffusive properties - flow speeds and lifetimes as functions of size - fiom SOHO/MDI Dopplergrams.

  18. Generation of active immunotoxins containing recombinant restrictocin.

    PubMed

    Rathore, D; Batra, J K

    1996-05-01

    Restrictocin, a toxin produced by the fungus Aspergillus restrictus, is a potent inhibitor of eukaryotic protein synthesis. Recombinant restrictocin was made in Escherichia coli and purified to homogeneity in large amounts. The recombinant protein was found to be poorly immunogenic in mice with low toxicity, when injected intraperitoneally. Two immunotoxins were constructed by coupling the recombinant restrictocin to an antibody to the human transferrin receptor, using a cleavable and a stable linkage. The immunotoxins so generated showed specific cytotoxic activity toward receptor bearing cells in tissue culture. Immunotoxin with a cleavable linkage, however, was more active than that containing a stable linkage. Restrictocin appears to be a promising candidate to be developed as a chimeric toxin for targeted therapy. PMID:8630074

  19. Proper Motion Of Emerging Active Regions

    NASA Astrophysics Data System (ADS)

    Tian, Lirong

    2009-05-01

    Observational and modeling results indicate that typically the leading magnetic field of bipolar active regions is often spatially more compact, while more dispersed and fragmented in following polarity. Tian & Alexander (2009, ApJ, 695) studied 15 emerging active regions and find that magnetic helicity flux injected into the corona by the leading polarity is generally several times larger than that injected by the following polarity. They argue that the asymmetry of the magnetic helicity should be responsible for the asymmetry of the magnetic morphology. This argument is supported by two resent model results that magnetic flux tubes with higher degree of twist (and therefor greater magnetic tension) have higher rates of emergence (Murray & Hood 2008, A&A, 479; Cheung et al. 2008, ApJ, 687). These results are consistent because the proper motion (related to the emergence) of the leading polarity was found to be faster than that of the following polarity (van Driel-Gesztelyi & Petrovay 1990, Solar Phys., 126). In this paper, we will reinvestigate the proper motion of leading and following polarities of the emerging active regions, and study possible relationship between the proper motion and magnetic helicity.

  20. Models of Impulsively Heated Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Airapetian, Vladimir; Klimchuk, J.

    2009-05-01

    A number of attempts to model solar active regions with steady coronal heating have been modestly successful at reproducing the observed soft X-ray emission, but they fail dramatically at explaining EUV observations. Since impulsive heating (nanoflare) models can reproduce individual EUV loops, it seems reasonable to consider that entire active regions are impulsively heated. However, nanoflares are characterized by many parameters, such as magnitude, duration, and time delay between successive events, and these parameters may depend on the strength of the magnetic field or the length of field lines, for example, so a wide range of active region models must be examined. We have recently begun such a study. Each model begins with a magnetic "skeleton” obtained by extrapolating an observed photospheric magnetogram into the corona. Field lines are populated with plasma using our highly efficient hydro code called Enthalpy Based Thermal Evolution of Loops (EBTEL). We then produce synthetic images corresponding to emission line or broad-band observations. By determining which set of nanoflare parameters best reproduces actual observations, we hope to constrain the properties of the heating and ultimately to reveal the physical mechanism. We here report on the initial progress of our study.

  1. GLOBAL DYNAMICS OF SUBSURFACE SOLAR ACTIVE REGIONS

    SciTech Connect

    Jouve, L.; Brun, A. S.

    2013-01-01

    We present three-dimensional numerical simulations of a magnetic loop evolving in either a convectively stable or unstable rotating shell. The magnetic loop is introduced into the shell in such a way that it is buoyant only in a certain portion in longitude, thus creating an {Omega}-loop. Due to the action of magnetic buoyancy, the loop rises and develops asymmetries between its leading and following legs, creating emerging bipolar regions whose characteristics are similar to those of observed spots at the solar surface. In particular, we self-consistently reproduce the creation of tongues around the spot polarities, which can be strongly affected by convection. We further emphasize the presence of ring-shaped magnetic structures around our simulated emerging regions, which we call 'magnetic necklace' and which were seen in a number of observations without being reported as of today. We show that those necklaces are markers of vorticity generation at the periphery and below the rising magnetic loop. We also find that the asymmetry between the two legs of the loop is crucially dependent on the initial magnetic field strength. The tilt angle of the emerging regions is also studied in the stable and unstable cases and seems to be affected both by the convective motions and the presence of a differential rotation in the convective cases.

  2. Solar irradiance variations due to active regions

    SciTech Connect

    Oster, L.; Schatten, K.H.; Sofia, S.

    1982-05-15

    We have been able to reproduce the variations of the solar irradiance observed by ACRIM to an accuracy of better than +- 0.4 W m/sup -2/, assuming that during the 6 month observation period in 1980 the solar luminosity was constant. The improvement over previous attempts is primarily due to the inclusion of faculae. The reproduction scheme uses simple geometrical data on spot and facula areas, and conventional parameters for the respective fluxes and angular dependencies. The quality of reproduction is not very sensitive to most of the details of these parameters; nevertheless, there conventional parameters cannot be very different from their actual values in the solar atmosphere. It is interesting that the time average of the integrated excess emission (over directions) of the faculae cancels out the integrated deficit produced by the spots, within an accuracy of about 10%. If this behavior were maintained over longer periods of time, say, on the order of an activity cycle, active regions could be viewed as a kind of lighthouse where the energy deficit near the normal direction, associated with the spots, is primarily reemitted close to the tangential directions by the faculae. The currently available data suggest that energy ''storage'' associated with the redirection of flux near active regions on the Sun is comparable to the lifetime of the faculae.

  3. Colony Rheology: Active Arthropods Generate Flows

    NASA Astrophysics Data System (ADS)

    Daniels, Karen; Mann, Michael; Charbonneau, Patrick

    2015-03-01

    Hydrodynamic-like flows are observed in biological systems as varied as bacteria, insects, birds, fish, and mammals. Both the phenomenology (e.g. front instabilities, milling motions) and the interaction types (hydrodynamic, direct contact, psychological, excluded-volume) strongly vary between systems, but a question common to all of them is to understand the role of particle-scale fluctuations in controlling large-scale rheological behaviors. We will address these questions through experiments on a new system, Tyrolichus casei (cheese mites), which live in dense, self-mixing colonies composed of a mixture of living mites and inert flour/detritus. In experiments performed in a Hele-Shaw geometry, we observe that the rheology of a colony is strongly dependent on the relative concentration of active and inactive particles. In addition to spreading flows, we also observe that the system can generate convective circulation and auto-compaction.

  4. Observations of an active region filament

    NASA Astrophysics Data System (ADS)

    Zong, W. G.; Tang, Y. H.; Fang, C.; Xu, A. A.

    An active region filament was well observed on September 4, 2002 with THEMIS at the Teide observatory and SOHO/MDI. The full Stokes parameters of the filament were obtained in Hα and FeI 6302 Å lines. Using the data, we have studied the fine structure of the filament and obtained the parameters at the barb endpoints, including intensity, velocity and longitudinal magnetic field. Our results indicate: (a) the Doppler velocities are quiet different at barb endpoints; (b) the longitudinal magnetic fields at the barb endpoints are very weak; (c) there is a strong magnetic field structure under the filament spine.

  5. Transient Thermoelectric Generator: An Active Load Story

    NASA Astrophysics Data System (ADS)

    Stockholm, J. G.; Goupil, C.; Maussion, P.; Ouerdane, H.

    2015-06-01

    Under stationary conditions, the optimization of maximum power output and efficiency of thermoelectric generators (TEG) is a well-known subject. Use of a finite-time thermodynamics (FTT) approach to the description of TEGs has demonstrated that there exists a closed feedback effect between the output electrical load value and the entering heat current. From the practical point of view, this effect is strongly evidenced by the use of direct current (DC-to-DC) converters as active loads. Both transient conditions and FTT contribute to a complex landscape of the optimization of the power and efficiencies of a TEG. It has been claimed that the use of inductive load may lead to a strong enhancement of the efficiency, and the frequency response of a TEG as a band-pass filter has also been recently reported. We consider these results using a classical linear Onsager approach of a TEG operating under transient conditions. We show that a trans-admittance may be defined as a coupling element between the input and the output, leading to the observed electric-to-thermal feedback. We discuss recent experiments on a TEG connected to an active load, which is reported to boast an efficiency exceeding the usual stationary DC thermoelectric efficiency.

  6. Pederson Current Dissipation In Emerging Active Regions

    NASA Astrophysics Data System (ADS)

    Leake, James E.; Linton, M. G.

    2011-05-01

    Pederson current dissipation in emerging active regions. Certain regions of the solar atmosphere, such as the photosphere and chromosphere, as well as prominences, contain a significant amount of neutral atoms, and a complete description of the plasma requires including the effects of partial ionization. In the chromosphere the dissipation of Pederson currents is important for the evolution of emerging magnetic fields. Due to the relatively high number density in the chromosphere, the ion-neutral collision time-scale is much smaller than timescales associated with flux emergence. Hence we use a single-fluid approach to model the partially ionized plasma. Looking at both the emergence of large-scale sub-surface structures, and the emergence and reconnection of undulatory fields, we investigate the effect of Pederson current dissipation on the state of the emerging field, on magnetic reconnection and on dissipative heating of the atmosphere. Specifically we examine the effect of motions across fieldlines in the partially ionized regions, and how this can increase the free energy supplied to the corona by flux emergence. We also look at reconnection associated with flux emergence in the partially ionized atmosphere, and how this can account for observed small-scale brightenings (Ellerman Bombs).

  7. Localizing Region-Based Active Contours

    PubMed Central

    Lankton, Shawn; Tannenbaum, Allen

    2009-01-01

    In this paper, we propose a natural framework that allows any region-based segmentation energy to be re-formulated in a local way. We consider local rather than global image statistics and evolve a contour based on local information. Localized contours are capable of segmenting objects with heterogeneous feature profiles that would be difficult to capture correctly using a standard global method. The presented technique is versatile enough to be used with any global region-based active contour energy and instill in it the benefits of localization. We describe this framework and demonstrate the localization of three well-known energies in order to illustrate how our framework can be applied to any energy. We then compare each localized energy to its global counterpart to show the improvements that can be achieved. Next, an in-depth study of the behaviors of these energies in response to the degree of localization is given. Finally, we show results on challenging images to illustrate the robust and accurate segmentations that are possible with this new class of active contour models. PMID:18854247

  8. HEROES Observations of a Quiescent Active Region

    NASA Astrophysics Data System (ADS)

    Shih, A. Y.; Christe, S.; Gaskin, J.; Wilson-Hodge, C.

    2014-12-01

    Hard X-ray (HXR) observations of solar flares reveal the signatures of energetic electrons, and HXR images with high dynamic range and high sensitivity can distinguish between where electrons are accelerated and where they stop. Even in the non-flaring corona, high-sensitivity HXR measurements may be able to detect the presence of electron acceleration. The High Energy Replicated Optics to Explore the Sun (HEROES) balloon mission added the capability of solar observations to an existing astrophysics balloon payload, HERO, which used grazing-incidence optics for direct HXR imaging. HEROES measures HXR emission from ~20 to ~75 keV with an angular resolution of 33" HPD. HEROES launched on 2013 September 21 from Fort Sumner, New Mexico, and had a successful one-day flight. We present the detailed analysis of the 7-hour observation of AR 11850, which sets new upper limits on the HXR emission from a quiescent active region, with corresponding constraints on the numbers of tens of keV energetic electrons present. Using the imaging capability of HEROES, HXR upper limits are also obtained for the quiet Sun surrounding the active region. We also discuss what can be achieved with new and improved HXR instrumentation on balloons.

  9. Linking the Weather Generator with Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Dubrovsky, Martin; Farda, Ales; Skalak, Petr; Huth, Radan

    2013-04-01

    One of the downscaling approaches, which transform the raw outputs from the climate models (GCMs or RCMs) into data with more realistic structure, is based on linking the stochastic weather generator with the climate model output. The present contribution, in which the parametric daily surface weather generator (WG) M&Rfi is linked to the RCM output, follows two aims: (1) Validation of the new simulations of the present climate (1961-1990) made by the ALADIN-Climate Regional Climate Model at 25 km resolution. The WG parameters are derived from the RCM-simulated surface weather series and compared to those derived from weather series observed in 125 Czech meteorological stations. The set of WG parameters will include statistics of the surface temperature and precipitation series (including probability of wet day occurrence). (2) Presenting a methodology for linking the WG with RCM output. This methodology, which is based on merging information from observations and RCM, may be interpreted as a downscaling procedure, whose product is a gridded WG capable of producing realistic synthetic multivariate weather series for weather-ungauged locations. In this procedure, WG is calibrated with RCM-simulated multi-variate weather series in the first step, and the grid specific WG parameters are then de-biased by spatially interpolated correction factors based on comparison of WG parameters calibrated with gridded RCM weather series and spatially scarcer observations. The quality of the weather series produced by the resultant gridded WG will be assessed in terms of selected climatic characteristics (focusing on characteristics related to variability and extremes of surface temperature and precipitation). Acknowledgements: The present experiment is made within the frame of projects ALARO-Climate (project P209/11/2405 sponsored by the Czech Science Foundation), WG4VALUE (project LD12029 sponsored by the Ministry of Education, Youth and Sports of CR) and VALUE (COST ES 1102

  10. Radio magnetography of the solar active regions

    NASA Astrophysics Data System (ADS)

    Gelfreikh, G. B.; Shibasaki, K.

    The observations of the solar magnetic fields is one of the most important basics for study of all important processes in structuring the solar atmosphere and most kinds of the release of the energy. The radio methods are of the special interest here because they gain the information on the magnetic field strength in the solar corona and upper chromosphere where traditional optical methods do not work. The construction of the Nobeyama radio heliograph opens a new era in usage radio methods for solar radio magnetography due to some unique property of the instrument: - The 2D mapping of the whole disk of the sun both in I and V Stokes parameters with resolution of 10 arcsec. - Regular observations (without breaks due to weather conditions), eight hours a day, already for seven years. The most effective and representative radio method of measuring the solar magnetic fields is to use polarization measurements of the thermal bremsstrahlung (free-free emission). It is applicable both to analysis of chromospheric and coronal magnetic fields and presents information on longitude component of the magnetic field strength in solar active regions. Three problems are met, however: (i) One needs to measure very low degree of polarization (small fraction of a percent); (ii) To get the real value of the field the spectral data are necessary. (iii) While observing an active region on the disk we have got the overlapping effects on polarized signal of the chromospheric and coronal magnetic fields. To get higher sensitivity the averaging of the radio maps over periods of about ten minutes were used with the results of sensitivity on V-maps of the order 0.1%. Observations for a number of dates have been analysed (August 22, 1992, October 31, 1992; June 30, 1993, July 22,1994, June 15, 1995 and some more). In all cases a very good similarity was found of the polarized regions (V-maps) with the Ca^ + plages in form and total coincidence with the direction of the magnetic fields on the

  11. Direct charge radioisotope activation and power generation

    DOEpatents

    Lal, Amit; Li, Hui; Blanchard, James P.; Henderson, Douglass L.

    2002-01-01

    An activator has a base on which is mounted an elastically deformable micromechanical element that has a section that is free to be displaced toward the base. An absorber of radioactively emitted particles is formed on the base or the displaceable section of the deformable element and a source is formed on the other of the displaceable section or the base facing the absorber across a small gap. The radioactive source emits charged particles such as electrons, resulting in a buildup of charge on the absorber, drawing the absorber and source together and storing mechanical energy as the deformable element is bent. When the force between the absorber and the source is sufficient to bring the absorber into effective electrical contact with the source, discharge of the charge between the source and absorber allows the deformable element to spring back, releasing the mechanical energy stored in the element. An electrical generator such as a piezoelectric transducer may be secured to the deformable element to convert the released mechanical energy to electrical energy that can be used to provide power to electronic circuits.

  12. FIP bias in a sigmoidal active region

    NASA Astrophysics Data System (ADS)

    Baker, D.; Brooks, D. H.; Démoulin, P.; van Driel-Gesztelyi, Lidia; Green, L. M.; Steed, K.; Carlyle, J.

    2014-01-01

    We investigate first ionization potential (FIP) bias levels in an anemone active region (AR) - coronal hole (CH) complex using an abundance map derived from Hinode/EIS spectra. The detailed, spatially resolved abundance map has a large field of view covering 359'' × 485''. Plasma with high FIP bias, or coronal abundances, is concentrated at the footpoints of the AR loops whereas the surrounding CH has a low FIP bias, ~1, i.e. photospheric abundances. A channel of low FIP bias is located along the AR's main polarity inversion line containing a filament where ongoing flux cancellation is observed, indicating a bald patch magnetic topology characteristic of a sigmoid/flux rope configuration.

  13. The composition of a coronal active region

    NASA Technical Reports Server (NTRS)

    Waljeski, K.; Moses, D.; Dere, K. P.; Saba, J. L. R.; Strong, K. T.; Webb, D. F.; Zarro, D. M.

    1994-01-01

    The relative abundances of iron, oxygen, magnesium, and neon in a coronal active region are determined from measurements of soft X-ray line and broadband intensities. The emission measure, temperature, and column density are derived from these measured intensities and are used to place a constraint on the abundances of the heavier elements relative to hydrogen in the corona. The intensity measurements were made on 1987 December 11, when an active region was observed jointly by the American Science and Engineering (AS&E) High Resolution Soft X-Ray Imaging Sounding-Rocket Payload and the X-Ray Polychromator Flat Crystal Spectrometer (FCS) onboard the Solar Maximum Mission spacecraft. The coordinated observations include images through two broadband filters (8 to 29 A and 8 to 39, 44 to 60 A) and profiles of six emission lines: Fe XVII (15.01 A), FE VIII (15.26 A), O VIII (18.97 A), Mg XI (9.17 A), Ne IX (13.44 A), and Fe XVIII (14.21 A). The effects of resonance scattering are considered in the interpretation of the FCS line intensities. We calculated the expected intensity ratio of the two Fe XVII lines as a function of optical depth and compared this ratio with the observed intensity ratio to obtain the optical depths of each of the lines and the column density. The line intensities and the broadband filtered images are consistent with the emission from a thermal plasma where Fe, O, Mg, and Ne have the 'adopted coronal' abundances of Meyer (1985b) relative to one another, but are not consistent with the emission from a plasma having photospheric abundances: The ratios of the abundances of the low first ionization potential (FIP) elements (Fe and Mg) to the abundances of the high-FIP elements (Ne and O) are higher than the ratios seen in the photosphere by a factor of about 3.5. This conclusion is independent of the assumption of either an isothermal or a multithermal plasma. The column densities derived from the Fe XVII line ratio and the geometry of the active

  14. Anger Style, Psychopathology, and Regional Brain Activity

    PubMed Central

    Stewart, Jennifer L.; Levin, Rebecca L.; Sass, Sarah M.; Heller, Wendy; Miller, Gregory A.

    2010-01-01

    Depression and anxiety often involve high levels of trait anger and disturbances in anger expression. Reported anger experience and outward anger expression have recently been associated with left-biased asymmetry of frontal cortical activity, assumed to reflect approach motivation. However, different styles of anger expression could presumably involve different brain mechanisms and/or interact with psychopathology to produce various patterns of brain asymmetry. The present study explored these issues by comparing resting regional electroencephalographic activity in participants high in trait anger who differed in anger expression style (high anger-in, high anger-out, both) and participants low in trait anger, with depression and anxiety systematically assessed. Trait anger, not anger-in or anger-out, predicted left-biased asymmetry at medial frontal EEG sites. The anger-in group reported higher levels of anxious apprehension than did the anger-out group. Furthermore, anxious apprehension moderated the relationship between trait anger, anger-in, and asymmetry in favor of the left hemisphere. Results suggest that motivational direction is not always the driving force behind the relationship of anger and left frontal asymmetry. Findings also support a distinction between anxious apprehension and anxious arousal. PMID:18837620

  15. A Tale of Two Super-Active Active Regions: On the Magnetic Origin of Flares and CMEs

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Dhakal, Suman; Chintzoglou, Georgios

    2015-04-01

    From a comparative study of two super-active active regions, we find that the magnetic origin of CMEs is different from that of flares. NOAA AR 12192 is one of the largest active regions in the recorded history with a sunspot number of 66 and area of 2410 millonths. During its passage through the front disk from Oct. 14-30, 2014, the active region produced 93 C-class, 30 M-class and 6 X-class flares. However, all six X-class flares are confined; in other words, none of them are associated with CMEs; most other flares are also confined. This behavior of low-CME production rate for such as a super active region is rather peculiar, given the usual hand-on-hand occurrence of CMEs with flares. To further strengthen this point, we also investigated the super-active NOAA AR 11429, which had a sunspot number of 28 and area of 1270 millionths. During its passage from March 02-17, 2012, the active region produced 47 C-class, 15 M-class and 3 X-class flares. In this active region, all three X-class flares were accompanied by CMEs, and the same for most M-class flares. Given the relative sizes of the two active regions, the production rates of flares are comparable. But the CME production rates are not. Through a careful study of the magnetic configuration on the surface and the extrapolated magnetic field in the corona, we argue that the generation of flares largely depends on the amount of free energy in the active region. On the other hand, the generation of CMEs largely depends on the complexity, such as measured by magnetic helicity. In particular, we argue that the high CME generation rate in the smaller active region is caused by the emergence and continuous generation of magnetic flux ropes in the region.

  16. Generating Orally-Active Galanin Analogs with Analgesic Activities

    PubMed Central

    Pruess, Timothy H.; Grussendorf, Erin; White, H. Steve; Bulaj, Grzegorz

    2014-01-01

    The endogenous neuropeptide galanin has anticonvulsant and analgesic properties mediated by galanin receptors expressed in the central and peripheral nervous systems. Our previous work showed that combination of truncation of the galanin peptide along with N-and C-terminal modifications afforded analogs that suppressed seizures or pain following intraperitoneal administration. To generate orally-active galanin analogs, the previously reported lead compound Gal-B2 (NAX 5055) was redesigned by (1) central truncation, (2) introduction of D-amino acids, (3) and addition of backbone spacers. Analog D-Gal(7-Ahp)-B2, containing 7-amino heptanoic acid as a backbone spacer and oligo-D-lysine motif at the C-terminus, exhibited anticonvulsant and analgesic activity post intraperitoneal administration. Oral administration of D-Gal(7-Ahp)-B2 demonstrated analgesic activity with reduction in both acute and inflammatory pain in the mouse formalin model of pain at doses as low as 8 mg/kg. PMID:22374865

  17. MAGNETIC ENERGY SPECTRA IN SOLAR ACTIVE REGIONS

    SciTech Connect

    Abramenko, Valentyna; Yurchyshyn, Vasyl

    2010-09-01

    Line-of-sight magnetograms for 217 active regions (ARs) with different flare rates observed at the solar disk center from 1997 January until 2006 December are utilized to study the turbulence regime and its relationship to flare productivity. Data from the SOHO/MDI instrument recorded in the high-resolution mode and data from the BBSO magnetograph were used. The turbulence regime was probed via magnetic energy spectra and magnetic dissipation spectra. We found steeper energy spectra for ARs with higher flare productivity. We also report that both the power index, {alpha}, of the energy spectrum, E(k) {approx} k{sup -}{alpha}, and the total spectral energy, W = {integral}E(k)dk, are comparably correlated with the flare index, A, of an AR. The correlations are found to be stronger than those found between the flare index and the total unsigned flux. The flare index for an AR can be estimated based on measurements of {alpha} and W as A = 10{sup b}({alpha}W){sup c}, with b = -7.92 {+-} 0.58 and c = 1.85 {+-} 0.13. We found that the regime of the fully developed turbulence occurs in decaying ARs and in emerging ARs (at the very early stage of emergence). Well-developed ARs display underdeveloped turbulence with strong magnetic dissipation at all scales.

  18. Microfluidic generation of acoustically active nanodroplets.

    PubMed

    Martz, Thomas D; Bardin, David; Sheeran, Paul S; Lee, Abraham P; Dayton, Paul A

    2012-06-25

    A microfluidic approach for the generation of perfluorocarbon nanodroplets as the primary emulsion with diameters as small as 300-400 nm is described. The system uses a pressure-controlled delivery of all reagents and increased viscosity in the continuous phase to drive the device into an advanced tip-streaming regime, which results in generation of droplets in the sub-micrometer range. Such nanodroplets may be appropriate for emerging biomedical applications. PMID:22467628

  19. Recurrent flares in active region NOAA 11283

    NASA Astrophysics Data System (ADS)

    Romano, P.; Zuccarello, F.; Guglielmino, S. L.; Berrilli, F.; Bruno, R.; Carbone, V.; Consolini, G.; de Lauretis, M.; Del Moro, D.; Elmhamdi, A.; Ermolli, I.; Fineschi, S.; Francia, P.; Kordi, A. S.; Landi Degl'Innocenti, E.; Laurenza, M.; Lepreti, F.; Marcucci, M. F.; Pallocchia, G.; Pietropaolo, E.; Romoli, M.; Vecchio, A.; Vellante, M.; Villante, U.

    2015-10-01

    Context. Flares and coronal mass ejections (CMEs) are solar phenomena that are not yet fully understood. Several investigations have been performed to single out their related physical parameters that can be used as indices of the magnetic complexity leading to their occurrence. Aims: In order to shed light on the occurrence of recurrent flares and subsequent associated CMEs, we studied the active region NOAA 11283 where recurrent M and X GOES-class flares and CMEs occurred. Methods: We use vector magnetograms taken by HMI/SDO to calculate the horizontal velocity fields of the photospheric magnetic structures, the shear and the dip angles of the magnetic field, the magnetic helicity flux distribution, and the Poynting fluxes across the photosphere due to the emergence and the shearing of the magnetic field. Results: Although we do not observe consistent emerging magnetic flux through the photosphere during the observation time interval, we detected a monotonic increase of the magnetic helicity accumulated in the corona. We found that both the shear and the dip angles have high values along the main polarity inversion line (PIL) before and after all the events. We also note that before the main flare of X2.1 GOES class, the shearing motions seem to inject a more significant energy than the energy injected by the emergence of the magnetic field. Conclusions: We conclude that the very long duration (about 4 days) of the horizontal displacement of the main photospheric magnetic structures along the PIL has a primary role in the energy release during the recurrent flares. This peculiar horizontal velocity field also contributes to the monotonic injection of magnetic helicity into the corona. This process, coupled with the high shear and dip angles along the main PIL, appears to be responsible for the consecutive events of loss of equilibrium leading to the recurrent flares and CMEs. A movie associated to Fig. 4 is available in electronic form at http://www.aanda.org

  20. The Limit of Free Magnetic Energy in Active Regions

    NASA Technical Reports Server (NTRS)

    Moore, Ron; Falconer, David; Sterling, Alphonse

    2012-01-01

    By measuring from active-region magnetograms a proxy of the free energy in the active region fs magnetic field, it has been found previously that (1) there is an abrupt upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region fs magnetic flux content, and (2) the free energy is usually near its limit when the field explodes in a CME/flare eruption. That is, explosive active regions are concentrated in a main-sequence path bordering the free-energy ]limit line in (flux content, free-energy proxy) phase space. Here, from measurement of Marshall Space Flight Center vector magnetograms, we find the magnetic condition that underlies the free ]energy limit and the accompanying main sequence of explosive active regions. Using a suitable free ]energy proxy measured from vector magnetograms of 44 active regions, we find that (1) in active regions at and near their free ]energy limit, the ratio of magnetic-shear free energy to the non ]free magnetic energy the potential field would have is approximately 1 in the core field, the field rooted along the neutral line, and (2) this ratio is progressively less in active regions progressively farther below their free ]energy limit. This shows that most active regions in which this core-field energy ratio is much less than 1 cannot be triggered to explode; as this ratio approaches 1, most active regions become capable of exploding; and when this ratio is 1 or greater, most active regions are compelled to explode. From these results we surmise the magnetic condition that determines the free ]energy limit is the ratio of the free magnetic energy to the non-free energy the active region fs field would have were it completely relaxed to its potential ]field configuration, and that this ratio is approximately 1 at the free-energy limit and in the main sequence of explosive active regions.

  1. Simulation of Ectopic Pacemakers in the Heart: Multiple Ectopic Beats Generated by Reentry inside Fibrotic Regions

    PubMed Central

    Gouvêa de Barros, Bruno; Weber dos Santos, Rodrigo; Lobosco, Marcelo; Alonso, Sergio

    2015-01-01

    The inclusion of nonconducting media, mimicking cardiac fibrosis, in two models of cardiac tissue produces the formation of ectopic beats. The fraction of nonconducting media in comparison with the fraction of healthy myocytes and the topological distribution of cells determines the probability of ectopic beat generation. First, a detailed subcellular microscopic model that accounts for the microstructure of the cardiac tissue is constructed and employed for the numerical simulation of action potential propagation. Next, an equivalent discrete model is implemented, which permits a faster integration of the equations. This discrete model is a simplified version of the microscopic model that maintains the distribution of connections between cells. Both models produce similar results when describing action potential propagation in homogeneous tissue; however, they slightly differ in the generation of ectopic beats in heterogeneous tissue. Nevertheless, both models present the generation of reentry inside fibrotic tissues. This kind of reentry restricted to microfibrosis regions can result in the formation of ectopic pacemakers, that is, regions that will generate a series of ectopic stimulus at a fast pacing rate. In turn, such activity has been related to trigger fibrillation in the atria and in the ventricles in clinical and animal studies. PMID:26583127

  2. Estimating evaporative vapor generation from automobiles based on parking activities.

    PubMed

    Dong, Xinyi; Tschantz, Michael; Fu, Joshua S

    2015-07-01

    A new approach is proposed to quantify the evaporative vapor generation based on real parking activity data. As compared to the existing methods, two improvements are applied in this new approach to reduce the uncertainties: First, evaporative vapor generation from diurnal parking events is usually calculated based on estimated average parking duration for the whole fleet, while in this study, vapor generation rate is calculated based on parking activities distribution. Second, rather than using the daily temperature gradient, this study uses hourly temperature observations to derive the hourly incremental vapor generation rates. The parking distribution and hourly incremental vapor generation rates are then adopted with Wade-Reddy's equation to estimate the weighted average evaporative generation. We find that hourly incremental rates can better describe the temporal variations of vapor generation, and the weighted vapor generation rate is 5-8% less than calculation without considering parking activity. PMID:25818089

  3. Fluidic Active Transducer for Electricity Generation

    NASA Astrophysics Data System (ADS)

    Yang, Youngjun; Park, Junwoo; Kwon, Soon-Hyung; Kim, Youn Sang

    2015-10-01

    Flows in small size channels have been studied for a long time over multidisciplinary field such as chemistry, biology and medical through the various topics. Recently, the attempts of electricity generation from the small flows as a new area for energy harvesting in microfluidics have been reported. Here, we propose for the first time a new fluidic electricity generator (FEG) by modulating the electric double layer (EDL) with two phase flows of water and air without external power sources. We find that an electric current flowed by the forming/deforming of the EDL with a simple separated phase flow of water and air at the surface of the FEG. Electric signals between two electrodes of the FEG are checked from various water/air passing conditions. Moreover, we verify the possibility of a self-powered air slug sensor by applying the FEG in the detection of an air slug.

  4. Fluidic Active Transducer for Electricity Generation.

    PubMed

    Yang, YoungJun; Park, Junwoo; Kwon, Soon-Hyung; Kim, Youn Sang

    2015-01-01

    Flows in small size channels have been studied for a long time over multidisciplinary field such as chemistry, biology and medical through the various topics. Recently, the attempts of electricity generation from the small flows as a new area for energy harvesting in microfluidics have been reported. Here, we propose for the first time a new fluidic electricity generator (FEG) by modulating the electric double layer (EDL) with two phase flows of water and air without external power sources. We find that an electric current flowed by the forming/deforming of the EDL with a simple separated phase flow of water and air at the surface of the FEG. Electric signals between two electrodes of the FEG are checked from various water/air passing conditions. Moreover, we verify the possibility of a self-powered air slug sensor by applying the FEG in the detection of an air slug. PMID:26511626

  5. Fluidic Active Transducer for Electricity Generation

    PubMed Central

    Yang, YoungJun; Park, Junwoo; Kwon, Soon-Hyung; Kim, Youn Sang

    2015-01-01

    Flows in small size channels have been studied for a long time over multidisciplinary field such as chemistry, biology and medical through the various topics. Recently, the attempts of electricity generation from the small flows as a new area for energy harvesting in microfluidics have been reported. Here, we propose for the first time a new fluidic electricity generator (FEG) by modulating the electric double layer (EDL) with two phase flows of water and air without external power sources. We find that an electric current flowed by the forming/deforming of the EDL with a simple separated phase flow of water and air at the surface of the FEG. Electric signals between two electrodes of the FEG are checked from various water/air passing conditions. Moreover, we verify the possibility of a self-powered air slug sensor by applying the FEG in the detection of an air slug. PMID:26511626

  6. Statistical Analysis of Acoustic Wave Parameters Near Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Rabello-Soares, M. Cristina; Bogart, Richard S.; Scherrer, Philip H.

    2016-08-01

    In order to quantify the influence of magnetic fields on acoustic mode parameters and flows in and around active regions, we analyze the differences in the parameters in magnetically quiet regions nearby an active region (which we call “nearby regions”), compared with those of quiet regions at the same disk locations for which there are no neighboring active regions. We also compare the mode parameters in active regions with those in comparably located quiet regions. Our analysis is based on ring-diagram analysis of all active regions observed by the Helioseismic and Magnetic Imager (HMI) during almost five years. We find that the frequency at which the mode amplitude changes from attenuation to amplification in the quiet nearby regions is around 4.2 mHz, in contrast to the active regions, for which it is about 5.1 mHz. This amplitude enhacement (the “acoustic halo effect”) is as large as that observed in the active regions, and has a very weak dependence on the wave propagation direction. The mode energy difference in nearby regions also changes from a deficit to an excess at around 4.2 mHz, but averages to zero over all modes. The frequency difference in nearby regions increases with increasing frequency until a point at which the frequency shifts turn over sharply, as in active regions. However, this turnover occurs around 4.9 mHz, which is significantly below the acoustic cutoff frequency. Inverting the horizontal flow parameters in the direction of the neigboring active regions, we find flows that are consistent with a model of the thermal energy flow being blocked directly below the active region.

  7. Cortical regions involved in the generation of musical structures during improvisation in pianists.

    PubMed

    Bengtsson, Sara L; Csíkszentmihályi, Mihály; Ullén, Fredrik

    2007-05-01

    Studies on simple pseudorandom motor and cognitive tasks have shown that the dorsolateral prefrontal cortex and rostral premotor areas are involved in free response selection. We used functional magnetic resonance imaging to investigate whether these brain regions are also involved in free generation of responses in a more complex creative behavior: musical improvisation. Eleven professional pianists participated in the study. In one condition, Improvise, the pianist improvised on the basis of a visually displayed melody. In the control condition, Reproduce, the participant reproduced his previous improvisation from memory. Participants were able to reproduce their improvisations with a high level of accuracy, and the contrast Improvise versus Reproduce was thus essentially matched in terms of motor output and sensory feedback. However, the Improvise condition required storage in memory of the improvisation. We therefore also included a condition FreeImp, where the pianist improvised but was instructed not to memorize his performance. To locate brain regions involved in musical creation, we investigated the activations in the Improvise-Reproduce contrast that were also present in FreeImp contrasted with a baseline rest condition. Activated brain regions included the right dorsolateral prefrontal cortex, the presupplementary motor area, the rostral portion of the dorsal premotor cortex, and the left posterior part of the superior temporal gyrus. We suggest that these regions are part of a network involved in musical creation, and discuss their possible functional roles. PMID:17488207

  8. Temporal evolution of continental lithospheric strength in actively deforming regions

    USGS Publications Warehouse

    Thatcher, W.; Pollitz, F.F.

    2008-01-01

    It has been agreed for nearly a century that a strong, load-bearing outer layer of earth is required to support mountain ranges, transmit stresses to deform active regions and store elastic strain to generate earthquakes. However the dept and extent of this strong layer remain controversial. Here we use a variety of observations to infer the distribution of lithospheric strength in the active western United States from seismic to steady-state time scales. We use evidence from post-seismic transient and earthquake cycle deformation reservoir loading glacio-isostatic adjustment, and lithosphere isostatic adjustment to large surface and subsurface loads. The nearly perfectly elastic behavior of Earth's crust and mantle at the time scale of seismic wave propagation evolves to that of a strong, elastic crust and weak, ductile upper mantle lithosphere at both earthquake cycle (EC, ???10?? to 103 yr) and glacio-isostatic adjustment (GIA, ???103 to 104 yr) time scales. Topography and gravity field correlations indicate that lithosphere isostatic adjustment (LIA) on ???106-107 yr time scales occurs with most lithospheric stress supported by an upper crust overlying a much weaker ductile subtrate. These comparisons suggest that the upper mantle lithosphere is weaker than the crust at all time scales longer than seismic. In contrast, the lower crust has a chameleon-like behavior, strong at EC and GIA time scales and weak for LIA and steady-state deformation processes. The lower crust might even take on a third identity in regions of rapid crustal extension or continental collision, where anomalously high temperatures may lead to large-scale ductile flow in a lower crustal layer that is locally weaker than the upper mantle. Modeling of lithospheric processes in active regions thus cannot use a one-size-fits-all prescription of rheological layering (relation between applied stress and deformation as a function of depth) but must be tailored to the time scale and tectonic

  9. Artificial Syntactic Violations Activate Broca's Region

    ERIC Educational Resources Information Center

    Petersson, Karl Magnus; Forkstam, Christian; Ingvar, Martin

    2004-01-01

    In the present study, using event-related functional magnetic resonance imaging, we investigated a group of participants on a grammaticality classification task after they had been exposed to well-formed consonant strings generated from an artificial regular grammar. We used an implicit acquisition paradigm in which the participants were exposed…

  10. Next Generation Active Buffet Suppression System

    NASA Technical Reports Server (NTRS)

    Galea, Stephen C.; Ryall, Thomas G.; Henderson, Douglas A.; Moses, Robert W.; White, Edward V.; Zimcik, David G.

    2003-01-01

    Buffeting is an aeroelastic phenomenon that is common to high performance aircraft, especially those with twin vertical tails like the F/A-18, at high angles of attack. These loads result in significant random stresses, which may cause fatigue damage leading to restricted capabilities and availability of the aircraft. This paper describes an international collaborative research activity among Australia, Canada and the United States involving the use of active structural control to alleviate the damaging structural response to these loads. The research program is being co-ordinated by the Air Force Research Laboratory (AFRL) and is being conducted under the auspices of The Technical Cooperative Program (TTCP). This truly unique collaborative program has been developed to enable each participating country to contribute resources toward a program that coalesces a broad range of technical knowledge and expertise into a single investigation. This collaborative program is directed toward a full-scale test of an F/A-18 empennage, which is an extension of an earlier initial test. The current program aims at applying advanced directional piezoactuators, the aircraft rudder, switch mode amplifiers and advanced control strategies on a full-scale structure to demonstrate the enhanced performance and capability of the advanced active BLA control system in preparation for a flight test demonstration.

  11. Tracked Active Region Patches for MDI and HMI

    NASA Astrophysics Data System (ADS)

    Turmon, Michael; Hoeksema, J. Todd; Bobra, Monica

    2014-06-01

    We describe tracked active-region patch data products that have been developed for HMI (HMI Active Region Patches, or HARPs) and for MDI (MDI Tracked Active Region Patches, or MDI TARPs). Both data products consist of tracked magnetic features on the scale of solar active regions. The now-released HARP data product covers 2010-present (>2000 regions to date). Like the HARPs, the MDI TARP data set is a catalog of active regions (ARs), indexed by a region ID number, analogous to a NOAA AR number, and time. The TARPs contain 6170 regions spanning 72000 images taken over 1996-2010, and will be availablein the MDI resident archive (RA).MDI TARPs are computed based on the 96-minute synoptic magnetograms and intensitygrams. As with the related HARP data product, the approximate threshold for significance is 100G. Use of both image types together allows faculae and sunspots to be separated out as sub-classes of activity, in addition to identifying the overall active region that they are in. After being identified in single images, the magnetically-active patches are grouped and tracked from image to image. Merges among growing active regions, as well as faint active regions hovering at the threshold of detection, are handled automatically. Regions are tracked from their inception until they decay within view, or transit off the visible disk. For each active region and for each time, a bitmap image is stored containing the precise outline of the active region. Also, metadata such as areas and integrated fluxes are stored for each AR and for each time. Because there is a cross-calibration between the HMI and MDI magnetograms (Liu et al. 2012), it is straightforward to use the same classification and tracking rules for the HMI HARPs and the MDI TARPs. We show results demonstrating region correspondence, region boundary agreement, and agreement of flux metadata using the approximately 140 regions in the May 2010-October 2010 time period. We envision several uses for these data

  12. Growth of Disturbances in a Flame-Generated Shear Region

    NASA Technical Reports Server (NTRS)

    Blackshear, Perry L , Jr

    1958-01-01

    Results are presented of an experimental and theoretical investigation of the growth of transverse velocity disturbances in the shear region caused by a flame in a duct. In the theoretical stability analysis, a flow field arising from a flame in a duct was analyzed. The flow was neutrally stable to symmetric disturbances and unstable to antisymmetric ones. In the experimental part of the program disturbances of various frequencies were imposed on a flame stabilized in a duct, and the effects were measured by shadow photography and photomultiplier-probe surveys.

  13. A Fractal Dimension Survey of Active Region Complexity

    NASA Technical Reports Server (NTRS)

    McAteer, R. T. James; Gallagher, Peter; Ireland, Jack

    2005-01-01

    A new approach to quantifying the magnetic complexity of active regions using a fractal dimension measure is presented. This fully-automated approach uses full disc MDI magnetograms of active regions from a large data set (2742 days of the SoHO mission; 9342 active regions) to compare the calculated fractal dimension to both Mount Wilson classification and flare rate. The main Mount Wilson classes exhibit no distinct fractal dimension distribution, suggesting a self-similar nature of all active regions. Solar flare productivity exhibits an increase in both the frequency and GOES X-ray magnitude of flares from regions with higher fractal dimensions. Specifically a lower threshold fractal dimension of 1.2 and 1.25 exists as a necessary, but not sufficient, requirement for an active region to produce M- and X-class flares respectively .

  14. Homologous flares and the evolution of NOAA Active Region 2372

    NASA Technical Reports Server (NTRS)

    Strong, K. T.; Smith, J. B., Jr.; Mccabe, M. K.; Machado, M. E.; Saba, J. L. R.; Simnett, G. M.

    1984-01-01

    A detailed record of the evolution of NOAA Active Region 2372 has been compiled by the FBS Homology Study Group. It was one of the most prolific flare-producing regions observed by SMM. The flares occurred in distinct stages which corresponded to particular evolutionary phases in the development of the active region magnetic field. By comparison with a similar but less productive active region, it is found that the activity seems to be related to the magnetic complexity of the region and the amount of shear in the field. Further, the soft X-ray emission in the quiescent active region is related to its flare rate. Within the broader definition of homology adopted, there was a degree of homology between the events within each stage of evolution of AR2372.

  15. OBSERVING CORONAL NANOFLARES IN ACTIVE REGION MOSS

    SciTech Connect

    Testa, Paola; DeLuca, Ed; Golub, Leon; Korreck, Kelly; Weber, Mark; De Pontieu, Bart; Martinez-Sykora, Juan; Title, Alan; Hansteen, Viggo; Cirtain, Jonathan; Winebarger, Amy; Kobayashi, Ken; Kuzin, Sergey; Walsh, Robert; DeForest, Craig

    2013-06-10

    The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A images of the upper transition region moss at an unprecedented spatial ({approx}0.''3-0.''4) and temporal (5.5 s) resolution. The Hi-C observations show in some moss regions variability on timescales down to {approx}15 s, significantly shorter than the minute-scale variability typically found in previous observations of moss, therefore challenging the conclusion of moss being heated in a mostly steady manner. These rapid variability moss regions are located at the footpoints of bright hot coronal loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly in the 94 A channel, and by the Hinode/X-Ray Telescope. The configuration of these loops is highly dynamic, and suggestive of slipping reconnection. We interpret these events as signatures of heating events associated with reconnection occurring in the overlying hot coronal loops, i.e., coronal nanoflares. We estimate the order of magnitude of the energy in these events to be of at least a few 10{sup 23} erg, also supporting the nanoflare scenario. These Hi-C observations suggest that future observations at comparable high spatial and temporal resolution, with more extensive temperature coverage, are required to determine the exact characteristics of the heating mechanism(s).

  16. Attainable region analysis for continuous production of second generation bioethanol

    PubMed Central

    2013-01-01

    Background Despite its semi-commercial status, ethanol production from lignocellulosics presents many complexities not yet fully solved. Since the pretreatment stage has been recognized as a complex and yield-determining step, it has been extensively studied. However, economic success of the production process also requires optimization of the biochemical conversion stage. This work addresses the search of bioreactor configurations with improved residence times for continuous enzymatic saccharification and fermentation operations. Instead of analyzing each possible configuration through simulation, we apply graphical methods to optimize the residence time of reactor networks composed of steady-state reactors. Although this can be easily made for processes described by a single kinetic expression, reactions under analysis do not exhibit this feature. Hence, the attainable region method, able to handle multiple species and its reactions, was applied for continuous reactors. Additionally, the effects of the sugars contained in the pretreatment liquor over the enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) were assessed. Results We obtained candidate attainable regions for separate enzymatic hydrolysis and fermentation (SHF) and SSF operations, both fed with pretreated corn stover. Results show that, despite the complexity of the reaction networks and underlying kinetics, the reactor networks that minimize the residence time can be constructed by using plug flow reactors and continuous stirred tank reactors. Regarding the effect of soluble solids in the feed stream to the reactor network, for SHF higher glucose concentration and yield are achieved for enzymatic hydrolysis with washed solids. Similarly, for SSF, higher yields and bioethanol titers are obtained using this substrate. Conclusions In this work, we demonstrated the capabilities of the attainable region analysis as a tool to assess the optimal reactor network with minimum

  17. IFLA General Conference, 1985. Division on Regional Activities. Papers.

    ERIC Educational Resources Information Center

    International Federation of Library Associations, The Hague (Netherlands).

    Papers on regional library activities which were presented at the 1985 International Federation of Library Associations (IFLA) conference include: (1) "Importance of Information Resources in National Development with Particular Reference to the Asian Scene" (Yogendra P. Dubey, India); (2) "Report of the Activities of the Regional Section for Asia…

  18. Slow Magnetosonic Waves and Fast Flows in Active Region Loops

    NASA Technical Reports Server (NTRS)

    Ofman, L.; Wang, T. J.; Davila, J. M.

    2012-01-01

    Recent extreme ultraviolet spectroscopic observations indicate that slow magnetosonic waves are present in active region (AR) loops. Some of the spectral data were also interpreted as evidence of fast (approx 100-300 km/s) quasiperiodic flows. We have performed three-dimensional magnetohydrodynamic (3D MHD) modeling of a bipolar AR that contains impulsively generated waves and flows in coronal loops. The model AR is initiated with a dipole magnetic field and gravitationally stratified density, with an upflow-driven steadily or periodically in localized regions at the footpoints of magnetic loops. The resulting flows along the magnetic field lines of the AR produce higher density loops compared to the surrounding plasma by injection of material into the flux tubes and the establishment of siphon flow.We find that the impulsive onset of flows with subsonic speeds result in the excitation of damped slow magnetosonic waves that propagate along the loops and coupled nonlinearly driven fast-mode waves. The phase speed of the slow magnetosonic waves is close to the coronal sound speed. When the amplitude of the driving pulses is increased we find that slow shock-like wave trains are produced. When the upflows are driven periodically, undamped oscillations are produced with periods determined by the periodicity of the upflows. Based on the results of the 3D MHD model we suggest that the observed slow magnetosonic waves and persistent upflows may be produced by the same impulsive events at the bases of ARs.

  19. SLOW MAGNETOSONIC WAVES AND FAST FLOWS IN ACTIVE REGION LOOPS

    SciTech Connect

    Ofman, L.; Wang, T. J.; Davila, J. M.

    2012-08-01

    Recent extreme ultraviolet spectroscopic observations indicate that slow magnetosonic waves are present in active region (AR) loops. Some of the spectral data were also interpreted as evidence of fast ({approx}100-300 km s{sup -1}) quasi-periodic flows. We have performed three-dimensional magnetohydrodynamic (3D MHD) modeling of a bipolar AR that contains impulsively generated waves and flows in coronal loops. The model AR is initiated with a dipole magnetic field and gravitationally stratified density, with an upflow-driven steadily or periodically in localized regions at the footpoints of magnetic loops. The resulting flows along the magnetic field lines of the AR produce higher density loops compared to the surrounding plasma by injection of material into the flux tubes and the establishment of siphon flow. We find that the impulsive onset of flows with subsonic speeds result in the excitation of damped slow magnetosonic waves that propagate along the loops and coupled nonlinearly driven fast-mode waves. The phase speed of the slow magnetosonic waves is close to the coronal sound speed. When the amplitude of the driving pulses is increased we find that slow shock-like wave trains are produced. When the upflows are driven periodically, undamped oscillations are produced with periods determined by the periodicity of the upflows. Based on the results of the 3D MHD model we suggest that the observed slow magnetosonic waves and persistent upflows may be produced by the same impulsive events at the bases of ARs.

  20. NASA/NREN: Next Generation Internet (NGI) Activities

    NASA Technical Reports Server (NTRS)

    desJardins, Richard; Freeman, Ken

    1998-01-01

    Various issues associated with next generation internet (NGI) and the NREN (NASA Research and Education Network) activities are presented in viewgraph form. Specific topics include: 1) NREN architecture; 2) NREN applications; and 3) NREN applied research.

  1. CHP REGIONAL APPLICATION CENTERS: ACTIVITIES AND SELECTED RESULTS

    SciTech Connect

    Schweitzer, Martin

    2010-08-01

    Between 2001 and 2005, the U.S. Department of Energy (DOE) created a set of eight Regional Application Centers (RACs) to facilitate the development and deployment of Combined Heat and Power (CHP) technologies. By utilizing the thermal energy that is normally wasted when electricity is produced at central generating stations, Combined Heat and Power installations can save substantial amounts of energy compared to more traditional technologies. In addition, the location of CHP facilities at or near the point of consumption greatly reduces or eliminates electric transmission and distribution losses. The regional nature of the RACs allows each one to design and provide services that are most relevant to the specific economic and market conditions in its particular geographic area. Between them, the eight RACs provide services to all 50 states and the District of Columbia. Through the end of the federal 2009 fiscal year (FY 2009), the primary focus of the RACs was on providing CHP-related information to targeted markets, encouraging the creation and adoption of public policies and incentives favorable to CHP, and providing CHP users and prospective users with technical assistance and support on specific projects. Beginning with the 2010 fiscal year, the focus of the regional centers broadened to include district energy and waste heat recovery and these entities became formally known as Clean Energy Application Centers, as required by the Energy Independence and Security Act (EISA) of 2007. In 2007, ORNL led a cooperative effort to establish metrics to quantify the RACs accomplishments. That effort began with the development of a detailed logic model describing RAC operations and outcomes, which provided a basis for identifying important activities and accomplishments to track. A data collection spreadsheet soliciting information on those activities for FY 2008 and all previous years of RAC operations was developed and sent to the RACs in the summer of 2008. This

  2. Emergent Public Spaces: Generative Activities on Function Interpolation

    ERIC Educational Resources Information Center

    Carmona, Guadalupe; Dominguez, Angeles; Krause, Gladys; Duran, Pablo

    2011-01-01

    This study highlights ways in which generative activities may be coupled with network-based technologies in the context of teacher preparation to enhance preservice teachers' cognizance of how their own experience as students provides a blueprint for the learning environments they may need to generate in their future classrooms. In this study, the…

  3. Source component mixing in the regions of arc magma generation

    NASA Astrophysics Data System (ADS)

    Arculus, Richard J.; Powell, Roger

    1986-05-01

    give rise to the trace element and isotopic systematics generally observed in arc basalts. Furthermore, subsequent melting of wedge-type peridotite in nonsubduction zone environments can result in complementary enrichment of the high field strength elements compared with arcs, and in the general isotopic similarity of hot spot and arc magmas. Although it is likely that the wedge-type peridotite in any arc is heterogeneously veined by previous inefficient melt extraction episodes, it is possible that the subduction zone environment is most conducive to the generation of veining.

  4. THE MAGNETIC ENERGY-HELICITY DIAGRAM OF SOLAR ACTIVE REGIONS

    SciTech Connect

    Tziotziou, Kostas; Georgoulis, Manolis K.; Raouafi, Nour-Eddine

    2012-11-01

    Using a recently proposed nonlinear force-free method designed for single-vector magnetograms of solar active regions, we calculate the instantaneous free magnetic energy and relative magnetic helicity budgets in 162 vector magnetograms corresponding to 42 different active regions. We find a statistically robust, monotonic correlation between the free magnetic energy and the relative magnetic helicity in the studied regions. This correlation implies that magnetic helicity, in addition to free magnetic energy, may be an essential ingredient for major solar eruptions. Eruptive active regions appear well segregated from non-eruptive ones in both free energy and relative helicity with major (at least M-class) flares occurring in active regions with free energy and relative helicity exceeding 4 Multiplication-Sign 10{sup 31} erg and 2 Multiplication-Sign 10{sup 42} Mx{sup 2}, respectively. The helicity threshold agrees well with estimates of the helicity contents of typical coronal mass ejections.

  5. The air quality and regional climate effects of widespread solar power generation under a changing regulatory environment

    NASA Astrophysics Data System (ADS)

    Millstein, D.; Zhai, P.; Menon, S.

    2011-12-01

    Over the past decade significant reductions of NOx and SOx emissions from coal burning power plants in the U.S. have been achieved due to regulatory action and substitution of new generation towards natural gas and wind power. Low natural gas prices, ever decreasing solar generation costs, and proposed regulatory changes, such as to the Cross State Air Pollution Rule, promise further long-run coal power plant emission reductions. Reduced power plant emissions have the potential to affect ozone and particulate air quality and influence regional climate through aerosol cloud interactions and visibility effects. Here we investigate, on a national scale, the effects on future (~2030) air quality and regional climate of power plant emission regulations in contrast to and combination with policies designed to aggressively promote solar electricity generation. A sophisticated, economic and engineering based, hourly power generation dispatch model is developed to explore the integration of significant solar generation resources (>10% on an energy basis) at various regions across the county, providing detailed estimates of substitution of solar generation for fossil fuel generation resources. Future air pollutant emissions from all sectors of the economy are scaled based on the U.S. Environmental Protection Agency's National Emission Inventory to account for activity changes based on population and economic projections derived from county level U.S. Census data and the Energy Information Administration's Annual Energy Outlook. Further adjustments are made for technological and regulatory changes applicable within various sectors, for example, emission intensity adjustments to on-road diesel trucking due to exhaust treatment and improved engine design. The future year 2030 is selected for the emissions scenarios to allow for the development of significant solar generation resources. A regional climate and air quality model (Weather Research and Forecasting, WRF model) is

  6. Meteosat Third Generation (MTG) critical technology pre-development activities

    NASA Astrophysics Data System (ADS)

    Aminou, Donny M. A.; Bézy, Jean Loup; Meynart, Roland; Blythe, Paul; Kraft, S.; Zayer, I.; Linder, M.; Falkner, M.; Luhmann, H. J.

    2009-09-01

    ESA and EUMETSAT have initiated joint preparatory activities for the formulation and definition of the Meteosat Third Generation (MTG) geostationary system to ensure the future continuity, and enhancement, of the current Meteosat Second Generation (MSG) system. The MTG programmatics are being established to ensure a seamless transition between the conclusion of the successful MSG operational system and the start of the new MTG operational system, with particular emphasis on continuity of the imagery missions. The MTG phase A studies were successfully concluded in December 2008 an re-consolidation phase B1 activities continued from January to July 2009. They were devoted to the MTG concept definition and requirements consolidation for meeting the User needs in the field of Nowcasting and Very Short Term Weather Forecasting (NWC), Medium/Short Range global and regional Numerical Weather Prediction (NWP), Climate, Air Quality and Composition Monitoring. The following missions have been analysed, measurement techniques studied and preliminary concepts established: - High Resolution Fast Imagery Mission (improved successor to MSG SEVIRI HRV mission) - Full Disk High Spectral Resolution Imagery Mission (improved successor to SEVIRI) - Lightning Imagery Mission - IR Sounding Mission - UV-VIS-NIR Sounding Mission Both space segment architecture and preliminary satellite and instrument concepts were investigated in the course of these studies, and a dual satellite configuration established comprising the Imaging satellite (MTG-I) and the sounding satellite (MTG-S). The study covered all elements to a level of detail allowing to establish a technical baseline, conclude on the feasibility of the system requirements and undertake preliminary programmatic evaluation. Riders to the Phase A studies (Phase B1 work) have been placed to further consolidate the satellite and payload definition and development, prior to the release of the Invitation To Tender (ITT) for the full space

  7. Regional Observation of Seismic Activity in Baekdu Mountain

    NASA Astrophysics Data System (ADS)

    Kim, Geunyoung; Che, Il-Young; Shin, Jin-Soo; Chi, Heon-Cheol

    2015-04-01

    Seismic unrest in Baekdu Mountain area between North Korea and Northeast China region has called attention to geological research community in Northeast Asia due to her historical and cultural importance. Seismic bulletin shows level of seismic activity in the area is higher than that of Jilin Province of Northeast China. Local volcanic observation shows a symptom of magmatic unrest in period between 2002 and 2006. Regional seismic data have been used to analyze seismic activity of the area. The seismic activity could be differentiated from other seismic phenomena in the region by the analysis.

  8. Active Generations: An Intergenerational Approach to Preventing Childhood Obesity

    ERIC Educational Resources Information Center

    Werner, Danilea; Teufel, James; Holtgrave, Peter L.; Brown, Stephen L.

    2012-01-01

    Background: Over the last 3 decades, US obesity rates have increased dramatically as more children and more adults become obese. This study explores an innovative program, Active Generations, an intergenerational nutrition education and activity program implemented in out-of-school environments (after school and summer camps). It utilizes older…

  9. The Smad3 linker region contains a transcriptional activation domain.

    PubMed

    Wang, Guannan; Long, Jianyin; Matsuura, Isao; He, Dongming; Liu, Fang

    2005-02-15

    Transforming growth factor-beta (TGF-beta)/Smads regulate a wide variety of biological responses through transcriptional regulation of target genes. Smad3 plays a key role in TGF-beta/Smad-mediated transcriptional responses. Here, we show that the proline-rich linker region of Smad3 contains a transcriptional activation domain. When the linker region is fused to a heterologous DNA-binding domain, it activates transcription. We show that the linker region physically interacts with p300. The adenovirus E1a protein, which binds to p300, inhibits the transcriptional activity of the linker region, and overexpression of p300 can rescue the linker-mediated transcriptional activation. In contrast, an adenovirus E1a mutant, which cannot bind to p300, does not inhibit the linker-mediated transcription. The native Smad3 protein lacking the linker region is unable to mediate TGF-beta transcriptional activation responses, although it can be phosphorylated by the TGF-beta receptor at the C-terminal tail and has a significantly increased ability to form a heteromeric complex with Smad4. We show further that the linker region and the C-terminal domain of Smad3 synergize for transcriptional activation in the presence of TGF-beta. Thus our findings uncover an important function of the Smad3 linker region in Smad-mediated transcriptional control. PMID:15588252

  10. Regions of Generation and Optical Thicknesses of dm-Zebra Lines

    NASA Astrophysics Data System (ADS)

    Yasnov, L. V.; Karlický, M.

    2015-07-01

    Using a new model based on the double plasma resonance (DPR), we show that the zebra structure seen in solar radio bursts is generated in the transition region and at the tops of the magnetic arcade. The magnetic field in zebra sources is probably weaker than 150 gauss. According to this model, a generation of zebras in stronger magnetic fields is improbable. The high-frequency boundary of decimetric zebras depends on the background electron plasma density, but not on the magnetic field strength in the generation regions. The bremsstrahlung absorption in atmospheric layers above the DPR zebra generation region and the cyclotron absorption in the DPR region and in the gyroresonance layers at higher altitudes limit the spectrum of zebras from both high-frequency and low-frequency sides. While the bremsstrahlung reduces the emission from the high-frequency side, the cyclotron absorption limits the low-frequency side. The observed frequency range and the number of observed zebra lines are determined not only by these absorptions, but also by appropriate distribution functions of superthermal electrons and plasma conditions in this region. Low-frequency (metric) zebra emissions can be generated at high altitudes. Computations show that such emissions can escape from the DPR generation region only at high gyro-harmonics () and with many zebra lines.

  11. Prediction of Active-Region CME Productivity from Magnetograms

    NASA Technical Reports Server (NTRS)

    Falconer, D. A.; Moore, R. L.; Gary, G. A.

    2004-01-01

    We report results of an expanded evaluation of whole-active-region magnetic measures as predictors of active-region coronal mass ejection (CME) productivity. Previously, in a sample of 17 vector magnetograms of 12 bipolar active regions observed by the Marshall Space Flight Center (MSFC) vector magnetograph, from each magnetogram we extracted a measure of the size of the active region (the active region s total magnetic flux a) and four measures of the nonpotentiality of the active region: the strong-shear length L(sub SS), the strong-gradient length L(sub SG), the net vertical electric current I(sub N), and the net-current magnetic twist parameter alpha (sub IN). This sample size allowed us to show that each of the four nonpotentiality measures was statistically significantly correlated with active-region CME productivity in time windows of a few days centered on the day of the magnetogram. We have now added a fifth measure of active-region nonpotentiality (the best-constant-alpha magnetic twist parameter (alpha sub BC)), and have expanded the sample to 36 MSFC vector magnetograms of 31 bipolar active regions. This larger sample allows us to demonstrate statistically significant correlations of each of the five nonpotentiality measures with future CME productivity, in time windows of a few days starting from the day of the magnetogram. The two magnetic twist parameters (alpha (sub 1N) and alpha (sub BC)) are normalized measures of an active region s nonpotentially in that they do not depend directly on the size of the active region, while the other three nonpotentiality measures (L(sub SS), L(sub SG), and I(sub N)) are non-normalized measures in that they do depend directly on active-region size. We find (1) Each of the five nonpotentiality measures is statistically significantly correlated (correlation confidence level greater than 95%) with future CME productivity and has a CME prediction success rate of approximately 80%. (2) None of the nonpotentiality

  12. THE COLD SHOULDER: EMISSION MEASURE DISTRIBUTIONS OF ACTIVE REGION CORES

    SciTech Connect

    Schmelz, J. T.; Pathak, S.

    2012-09-10

    The coronal heating mechanism for active region core loops is difficult to determine because these loops are often not resolved and cannot be studied individually. Rather, we concentrate on the 'inter-moss' areas between loop footpoints. We use observations from the Hinode EUV Imaging Spectrometer and the X-Ray Telescope to calculate the emission measure distributions of eight inter-moss areas in five different active regions. The combined data sets provide both high- and low-temperature constraints and ensure complete coverage in the temperature range appropriate for active regions. For AR 11113, the emission can be modeled with heating events that occur on timescales less than the cooling time. The loops in the core regions appear to be close to equilibrium and are consistent with steady heating. The other regions studied, however, appear to be dominated by nanoflare heating. Our results are consistent with the idea that active region age is an important parameter in determining whether steady or nanoflare heating is primarily responsible for the core emission, that is, older regions are more likely to be dominated by steady heating, while younger regions show more evidence of nanoflares.

  13. Active Ageing Level of Older Persons: Regional Comparison in Thailand

    PubMed Central

    Haque, Md. Nuruzzaman

    2016-01-01

    Active ageing level and its discrepancy in different regions (Bangkok, Central, North, Northeast, and South) of Thailand have been examined for prioritizing the policy agenda to be implemented. Attempt has been made to test preliminary active ageing models for Thai older persons and hence active ageing index (AAI, ranges from 0 to 1) has been estimated. Using nationally representative data and confirmatory factor analysis approach, this study justified active ageing models for female and male older persons in Thailand. Results revealed that active ageing level of Thai older persons is not high (mean AAIs for female and male older persons are 0.64 and 0.61, resp., and those are significantly different (p < 0.001)). Mean AAI in Central region is lower than North, Northeast, and South regions but there is no significant difference in the latter three regions of Thailand. Special emphasis should be given to Central region and policy should be undertaken for increasing active ageing level. Implementation of an Integrated Active Ageing Package (IAAP), containing policies for older persons to improve their health and economic security, to promote participation in social groups and longer working lives, and to arrange learning programs, would be helpful for increasing older persons' active ageing level in Thailand. PMID:27375903

  14. DISTRIBUTION OF ELECTRIC CURRENTS IN SOLAR ACTIVE REGIONS

    SciTech Connect

    Török, T.; Titov, V. S.; Mikić, Z.; Leake, J. E.; Archontis, V.; Linton, M. G.; Dalmasse, K.; Aulanier, G.; Kliem, B.

    2014-02-10

    There has been a long-standing debate on the question of whether or not electric currents in solar active regions are neutralized. That is, whether or not the main (or direct) coronal currents connecting the active region polarities are surrounded by shielding (or return) currents of equal total value and opposite direction. Both theory and observations are not yet fully conclusive regarding this question, and numerical simulations have, surprisingly, barely been used to address it. Here we quantify the evolution of electric currents during the formation of a bipolar active region by considering a three-dimensional magnetohydrodynamic simulation of the emergence of a sub-photospheric, current-neutralized magnetic flux rope into the solar atmosphere. We find that a strong deviation from current neutralization develops simultaneously with the onset of significant flux emergence into the corona, accompanied by the development of substantial magnetic shear along the active region's polarity inversion line. After the region has formed and flux emergence has ceased, the strong magnetic fields in the region's center are connected solely by direct currents, and the total direct current is several times larger than the total return current. These results suggest that active regions, the main sources of coronal mass ejections and flares, are born with substantial net currents, in agreement with recent observations. Furthermore, they support eruption models that employ pre-eruption magnetic fields containing such currents.

  15. Photospheric Magnetic Diffusion by Measuring Moments of Active Regions

    NASA Astrophysics Data System (ADS)

    Engell, Alexander; Longcope, D.

    2013-07-01

    Photospheric magnetic surface diffusion is an important constraint for the solar dynamo. The HMI Active Region Patches (HARPs) program automatically identify all magnetic regions above a certain flux. In our study we measure the moments of ARs that are no longer actively emerging and can thereby give us good statistical constraints on photospheric diffusion. We also present the diffusion properties as a function of latitude, flux density, and single polarity (leading or following) within each HARP.

  16. Differential activity of regions of transversus abdominis during trunk rotation.

    PubMed

    Urquhart, Donna M; Hodges, Paul W

    2005-05-01

    The role of the abdominal muscles in trunk rotation is not comprehensively understood. This study investigated the electromyographic (EMG) activity of anatomically distinct regions of the abdominal muscles during trunk rotation in six subjects with no history of spinal pain. Fine-wire electrodes were inserted into the right abdominal wall; upper region of transversus abdominis (TrA), middle region of TrA, obliquus internus abdominis (OI) and obliquus externus abdominis (OE), and lower region of TrA and OI. Surface electrodes were placed over right rectus abdominis (RA). Subjects performed trunk rotation to the left and right in sitting by rotating their pelvis relative to a fixed thorax. EMG activity was recorded in relaxed supine and sitting, and during an isometric hold at end range. TrA was consistently active during trunk rotation, with the recruitment patterns of the upper fascicles opposite to that of the middle and lower fascicles. During left rotation, there was greater activity of the lower and middle regions of contralateral TrA and the lower region of contralateral OI. The upper region of ipsilateral TrA and OE were predominately active during right rotation. In contrast, there was no difference in activity of RA and middle OI between directions (although middle OI was different between directions for all but one subject). This study indicates that TrA is active during trunk rotation, but this activity varies between muscle regions. These normative data will assist in understanding the role of TrA in lumbopelvic control and movement, and the effect of spinal pain on abdominal muscle recruitment. PMID:15940481

  17. Solar Irradiance Variations on Active Region Time Scales

    NASA Technical Reports Server (NTRS)

    Labonte, B. J. (Editor); Chapman, G. A. (Editor); Hudson, H. S. (Editor); Willson, R. C. (Editor)

    1984-01-01

    The variations of the total solar irradiance is an important tool for studying the Sun, thanks to the development of very precise sensors such as the ACRIM instrument on board the Solar Maximum Mission. The largest variations of the total irradiance occur on time scales of a few days are caused by solar active regions, especially sunspots. Efforts were made to describe the active region effects on total and spectral irradiance.

  18. Radio Coronal Magnetography of a Large Active Region

    NASA Astrophysics Data System (ADS)

    Bastian, Timothy S.; Gary, Dale E.; White, Stephen; Fleishman, Gregory; Chen, Bin

    2015-04-01

    Quantitative knowledge of coronal magnetic fields is fundamental to understanding energetic phenomena such as solar flares. Flares occur in solar active regions where strong, non-potential magnetic fields provide free energy. While constraints on the coronal magnetic field topology are readily available through high resolution SXR and EUV imaging of solar active regions, useful quantitative measurements of coronal magnetic fields have thus far been elusive. Recent progress has been made at infrared (IR) wavelengths in exploiting both the Zeeman and Hanle effects to infer the line-of-sight magnetic field strength or the orientation of the magnetic field vector in the plane of the sky above the solar limb. However, no measurements of coronal magnetic fields against the solar disk are possible using IR observations. Radio observations of gyroresonance emission from active regions offer the means of measuring coronal magnetic fields above the limb and on the solar disk. In particular, for plasma plasma conditions in the solar corona, active regions typically become optically thick to emission over a range of radio frequencies through gyroresonance absorption at a low harmonic of the electron gyrofrequency. The specific range of resonant frequencies depends on the range of coronal magnetic field strengths present in the active region.The Karl G. Jansky Very Large Array was used in November 2014 to image NOAA/USAF active region AR12209 over a continuous frequency range of 1-8 GHz, corresponding to a wavelength range of 3.75-30 cm. This frequency range is sensitive to coronal magnetic field strengths ranging from ~120-1400G. The active region was observed on four different dates - November 18, 20, 22, and 24 - during which the active region longitude ranged from -15 to +70 degrees, providing a wide range of aspect angles. In this paper we provide a preliminary description of the coronal magnetic field measurements derived from the radio observations.

  19. Some features of active regions and bursts in millimetric range.

    NASA Astrophysics Data System (ADS)

    Yu, Xingfeng; Yao, Jinxing

    1995-09-01

    The characteristics of active regions and bursts at mm wavelengths, observed with the 13.7 m radio telescope at Quinghai from Nov 16 to Dec 1, 1993, are analyzed. It appears that the active region collapsed and vanished while there occurred a coronal loop with two polarities. GRE bursts at mm wavelength may be interpreted by thermal gyro-resonance radiation and are part of the chromospheric eruption. There is no indication of FFS in 10 ms recordings.

  20. Category-specific activations during word generation reflect experiential sensorimotor modalities

    PubMed Central

    Hwang, Kai; Palmer, Erica D.; Basho, Surina; Zadra, Jonathan R.; Müller, Ralph-Axel

    2009-01-01

    According to the sensorimotor theory of lexicosemantic organization, semantic representations are neurally distributed and anatomically linked to category-specific sensory areas. Previous functional neuroimaging studies have demonstrated category specificity in lexicosemantic representations. However, little evidence is available from word generation paradigms, which provide access to semantic representations while minimizing confounds resulting from low-level perceptual features of stimulus presentation. In this study, 13 healthy young adults underwent fMRI scanning while performing a word generation task, generating exemplars to nine different semantic categories. Each semantic category was assigned to one of three superordinate category types, based upon sensorimotor modalities (visual, motor, somatosensory) presumed to predominate in lexical acquisition. For word generation overall, robust activation was seen in left inferior frontal cortex. Analyses by sensorimotor modality categories yielded activations in brain regions related to perceptual and motor processing: Visual categories activated extrastriate cortex, motor categories activated the intraparietal sulcus and posterior middle temporal cortex, and somatosensory categories activated postcentral and inferior parietal regions. Our results are consistent with the sensorimotor theory, according to which lexicosemantic representations are distributed across brain regions participating in sensorimotor processing associated with the experiential components of lexicosemantic acquisition. PMID:19559802

  1. A Study on Grid-Square Statistics Based Estimation of Regional Electricity Demand and Regional Potential Capacity of Distributed Generators

    NASA Astrophysics Data System (ADS)

    Kato, Takeyoshi; Sugimoto, Hiroyuki; Suzuoki, Yasuo

    We established a procedure for estimating regional electricity demand and regional potential capacity of distributed generators (DGs) by using a grid square statistics data set. A photovoltaic power system (PV system) for residential use and a co-generation system (CGS) for both residential and commercial use were taken into account. As an example, the result regarding Aichi prefecture was presented in this paper. The statistical data of the number of households by family-type and the number of employees by business category for about 4000 grid-square with 1km × 1km area was used to estimate the floor space or the electricity demand distribution. The rooftop area available for installing PV systems was also estimated with the grid-square statistics data set. Considering the relation between a capacity of existing CGS and a scale-index of building where CGS is installed, the potential capacity of CGS was estimated for three business categories, i.e. hotel, hospital, store. In some regions, the potential capacity of PV systems was estimated to be about 10,000kW/km2, which corresponds to the density of the existing area with intensive installation of PV systems. Finally, we discussed the ratio of regional potential capacity of DGs to regional maximum electricity demand for deducing the appropriate capacity of DGs in the model of future electricity distribution system.

  2. Earth resources-regional transfer activity contracts review

    NASA Technical Reports Server (NTRS)

    Bensko, J., Jr.; Daniels, J. L.; Downs, S. W., Jr.; Jones, N. L.; Morton, R. R.; Paludan, C. T.

    1977-01-01

    A regional transfer activity contracts review held by the Earth Resources Office was summarized. Contracts in the earth resources field primarily directed toward applications of satellite data and technology in solution of state and regional problems were reviewed. A summary of the progress of each contract was given in order to share experiences of researchers across a seven state region. The region included Missouri, Kentucky, Tennessee, Mississippi, Alabama, Georgia, and North Carolina. Research in several earth science disciplines included forestry, limnology, water resources, land use, geology, and mathematical modeling. The use of computers for establishment of information retrieval systems was also emphasized.

  3. Differential Magnetic Field Shear in an Active Region

    NASA Technical Reports Server (NTRS)

    Schmeider, B.; DeMoulin, P.; Aulanier, G.; Golub, Leon

    1997-01-01

    The three-dimensional extrapolation of magnetic field lines from a magnetogram obtained at Kitt Peak allows us to understand the global structure of the NOAA active region 6718, as observed in X-rays with the Normal Incidence X-ray Telescope (NIXT) and in Ha with the Multichannel Subtractive Double Pass spectrograph (MSDP) in Meudon on 1991 July 11. This active region was in a quiet stage. Bright X-ray loops connect plages having field strengths of approx. 300 G, while H-alpha fibriles connect penumbrae having strong spot fields to the surrounding network. Small, intense X-ray features in the moat region around a large spot, which could be called X-ray-bright points, are due mainly to the emergence of magnetic flux and merging of these fields with surrounding ones. A set of large-scale, sheared X-ray loops is observed in the central part of the active region. Based on the fit between the observed coronal structure and the field configurations (and assuming a linear force-free field), we propose a differential magnetic field shear model for this active region. The decreasing shear in outer portions of the active region may indicate a continual relaxation of the magnetic field to a lower energy state in the progressively older portions of the AR.

  4. Active Tectonics And Modern Geodynamics Of Sub-Yerevan Region

    NASA Astrophysics Data System (ADS)

    Avanesyan, M.

    2004-05-01

    The given work is dedicated to active tectonics and modern geodynamics of Sub-Yerevan region. This region is interesting as a one of regions with maximal seismic activity in Armenia. The high level of seismic risk of this region is conditioned by high level of seismic hazard, high density of the population, as well as presence of objects of special importance and industrial capacities. The modern structure of Sub-Yerevan region and the adjacent area, as well as the Caucasus entirely, has mosaic-block appearance, typical for collision zone of Arabian and Eurasian plates. Distinctively oriented active faults of various ranges and morphological types are distinguished. These faults, in their turn, form various-scale active blocks of the Earth's crust and their movement defines seismic activity of the region. The researches show, that all strong earthquakes in the region were caused by movements by newest and activated ancient faults. In order to reveal the character of Earth's crust active blocks movement, separation of high gradients of horizontal and vertical movements and definition of stress fields highest concentration regions by GPS observations, high-accuracy leveling and study of earthquake focal mechanisms a new seismotectonic model is developed, which represents a combination of tectonic structure, seismic data, newest and modern movements. On the basis of comparison and analysis of these data zones with potential maximal seismic hazard are separated. The zone of joint of Azat-Sevan active and Yerevan abysmal faults is the most active on the territory of Sub-Yerevan region. The directions relatively the Earth's crust movement in the zones of horizontal and vertical movement gradients lead to conclusion, that Aragats-Tsakhkunian and Gegam active blocks undergo clockwise rotation. This means, that additional concentration of stress must be observed in block corners, that is confirmed by location of strong earthquakes sources. Thus, on the North 1988 Spitak (M

  5. Universities and Economic Development Activities: A UK Regional Comparison

    ERIC Educational Resources Information Center

    Decter, Moira; Cave, Frank; Rose, Mary; Peers, Gill; Fogg, Helen; Smith, Susan M.

    2011-01-01

    A number of UK universities prioritize economic development or regeneration activities and for some of these universities such activities are the main focus of their knowledge transfer work. This study compares two regions of the UK--the North West and the South East of England--which have very different levels of economic performance.…

  6. Multiscale Aspects of Generation of High-Gamma Activity during Seizures in Human Neocortex123

    PubMed Central

    Marcuccilli, Charles J.; Ben-Mabrouk, Faiza; Lew, Sean M.; Goodman, Robert R.; McKhann, Guy M.; Frim, David M.; Kohrman, Michael H.; Schevon, Catherine A.; van Drongelen, Wim

    2016-01-01

    High-gamma (HG; 80-150 Hz) activity in macroscopic clinical records is considered a marker for critical brain regions involved in seizure initiation; it is correlated with pathological multiunit firing during neocortical seizures in the seizure core, an area identified by correlated multiunit spiking and low frequency seizure activity. However, the effects of the spatiotemporal dynamics of seizure on HG power generation are not well understood. Here, we studied HG generation and propagation, using a three-step, multiscale signal analysis and modeling approach. First, we analyzed concurrent neuronal and microscopic network HG activity in neocortical slices from seven intractable epilepsy patients. We found HG activity in these networks, especially when neurons displayed paroxysmal depolarization shifts and network activity was highly synchronized. Second, we examined HG activity acquired with microelectrode arrays recorded during human seizures (n = 8). We confirmed the presence of synchronized HG power across microelectrode records and the macroscale, both specifically associated with the core region of the seizure. Third, we used volume conduction-based modeling to relate HG activity and network synchrony at different network scales. We showed that local HG oscillations require high levels of synchrony to cross scales, and that this requirement is met at the microscopic scale, but not within macroscopic networks. Instead, we present evidence that HG power at the macroscale may result from harmonics of ongoing seizure activity. Ictal HG power marks the seizure core, but the generating mechanism can differ across spatial scales. PMID:27257623

  7. The EM fields in the Solid Generated by a Fault in a Porous Region

    NASA Astrophysics Data System (ADS)

    Ren, H.; Huang, Q.; Chen, X.

    2015-12-01

    Electrokinetic effect, as one of the most possible generation mechanisms of the seismo-electromagnetic phenomenons associated with natural earthquakes, has interested many researchers. Besides, it is also considered as a potential tool for the water/oil exploration. Recently, we numerically investigated the electromagnetic (EM) fields due to the electrokinetic effect in mixed layered model. The mixed model comprises not only porous layers but also solid layers. We firstly tested a two-layer mixed model. The numerical results show that, in addition to the radiation EM fields, another kind of evanescent EM fields can be generated by the seismic waves arriving at the interface with incident angles greater the critical angle. The evanescent EM fields decay faster than the radiation EM fields when getting away from the interface. For the seismic frequency band, the evanescent EM fields in the solid are still measurable at a distance of, e.g., 2km to the interface. We then tested a eight-layer mixed model. The top and bottom layers are solid and the other layers are porous. A finite fault of 20x10km is located in the porous region. The focal depth is 8km. The applied source time function is a ramp fuction with an arise time of 0.8s. Point stacking method was used to compute the wave-fields caused by the finite fault. Our nuemrical results show that, this model can generate the EM fields before the arrival of seismic waves as well as the residual EM fields. Both the two kinds of EM fields have been observed in field observations. There is a possibility that the anomalous EM activities before big earthquakes may be caused by the fluid flow in the shallow Earth as a result of the stress changes.

  8. EVIDENCE OF IMPULSIVE HEATING IN ACTIVE REGION CORE LOOPS

    SciTech Connect

    Tripathi, Durgesh; Mason, Helen E.; Klimchuk, James A.

    2010-11-01

    Using a full spectral scan of an active region from the Extreme-Ultraviolet Imaging Spectrometer (EIS) we have obtained emission measure EM(T) distributions in two different moss regions within the same active region. We have compared these with theoretical transition region EMs derived for three limiting cases, namely, static equilibrium, strong condensation, and strong evaporation from Klimchuk et al. The EM distributions in both the moss regions are strikingly similar and show a monotonically increasing trend from log T[K] = 5.15-6.3. Using photospheric abundances, we obtain a consistent EM distribution for all ions. Comparing the observed and theoretical EM distributions, we find that the observed EM distribution is best explained by the strong condensation case (EM{sub con}), suggesting that a downward enthalpy flux plays an important and possibly dominant role in powering the transition region moss emission. The downflows could be due to unresolved coronal plasma that is cooling and draining after having been impulsively heated. This supports the idea that the hot loops (with temperatures of 3-5 MK) seen in the core of active regions are heated by nanoflares.

  9. Income Generation Activities among Academic Staffs at Malaysian Public Universities

    ERIC Educational Resources Information Center

    Ahmad, Abd Rahman; Soon, Ng Kim; Ting, Ngeoh Pei

    2015-01-01

    Income generation activities have been acquainted among public higher education institutions (HEIs) in Malaysia. Various factors that brought to insufficient of funding caused Higher Education Institutions(HEIs) to seek for additional income as to support the operation expenses. Financial sustainability issues made up the significant impact…

  10. Generation of High Frequency Electric Field Activity by Turbulence in the Earth's Magnetotail

    NASA Astrophysics Data System (ADS)

    Stawarz, J. E.; Ergun, R.

    2013-12-01

    Bursty Bulk Flow (BBF) events, frequently observed in the magnetotail, carry significant energy and mass from the tail region at ~20 RE into the near-earth plasma sheet at ~10 RE, which is often referred to as the BBF 'braking region'. A number of possible channels are available for the transfer or dissipation of energy in BBF events including adiabatic heating of ions and electrons, the propagation of Alfvén waves out of the BBF braking region and into the auroral region, and energy dissipation within the braking region itself. This study investigates the generation of strong high frequency electric field activity observed within the braking region. A theory by which the large and small scales are coupled through a turbulent cascade of Alfvén waves, generated by the BBF braking event, is considered. At small kinetic spatial scales magnetic field aligned currents can be generated. These currents can be unstable to high frequency electrostatic waves, as well as, non-linear electrostatic structures such as double layers and electron phase space holes that are observed in the breaking region. The theoretical work is supported by observations from the THEMIS satellites. This work provides a possible mechanism for the dissipation of energy in turbulent plasma environments.

  11. The Generation Effect: Activating Broad Neural Circuits During Memory Encoding

    PubMed Central

    Rosner, Zachary A.; Elman, Jeremy A.; Shimamura, Arthur P.

    2012-01-01

    The generation effect is a robust memory phenomenon in which actively producing material during encoding acts to improve later memory performance. In an fMRI analysis, we explored the neural basis of this effect. During encoding, participants generated synonyms from word-fragment cues (e.g. GARBAGE-W_ST_) or read other synonym pairs (e.g. GARBAGE-WASTE). Compared to simply reading target words, generating target words significantly improved later recognition memory performance. During encoding, this benefit was associated with a broad neural network that involved both prefrontal (inferior frontal gyrus, middle frontal gyrus) and posterior cortex (inferior temporal gyrus, lateral occipital cortex, parahippocampal gyrus, ventral posterior parietal cortex). These findings define the prefrontal-posterior cortical dynamics associated with the mnemonic benefits underlying the generation effect. PMID:23079490

  12. Eruptions that Drive Coronal Jets in a Solar Active Region

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David A.; Panesar, Navdeep K.; Akiyama, Sachiko; Yashiro, Seiji; Gopalswamy, Nat

    2016-01-01

    Solar coronal jets are common in both coronal holes and in active regions (e.g., Shibata et al. 1992, Shimojo et al. 1996, Cirtain et al. 2007. Savcheva et al. 2007). Recently, Sterling et al. (2015), using data from Hinode/XRT and SDO/AIA, found that coronal jets originating in polar coronal holes result from the eruption of small-scale filaments (minifilaments). The jet bright point (JBP) seen in X-rays and hotter EUV channels off to one side of the base of the jet's spire develops at the location where the minifilament erupts, consistent with the JBPs being miniature versions of typical solar flares that occur in the wake of large-scale filament eruptions. Here we consider whether active region coronal jets also result from the same minifilament-eruption mechanism, or whether they instead result from a different mechanism (e.g. Yokoyama & Shibata 1995). We present observations of an on-disk active region (NOAA AR 11513) that produced numerous jets on 2012 June 30, using data from SDO/AIA and HMI, and from GOES/SXI. We find that several of these active region jets also originate with eruptions of miniature filaments (size scale 20'') emanating from small-scale magnetic neutral lines of the region. This demonstrates that active region coronal jets are indeed frequently driven by minifilament eruptions. Other jets from the active region were also consistent with their drivers being minifilament eruptions, but we could not confirm this because the onsets of those jets were hidden from our view. This work was supported by funding from NASA/LWS, NASA/HGI, and Hinode. A full report of this study appears in Sterling et al. (2016).

  13. Generating Coherent Patterns of Activity from Chaotic Neural Networks

    PubMed Central

    Sussillo, David; Abbott, L. F.

    2009-01-01

    Neural circuits display complex activity patterns both spontaneously and when responding to a stimulus or generating a motor output. How are these two forms of activity related? We develop a procedure called FORCE learning for modifying synaptic strengths either external to or within a model neural network to change chaotic spontaneous activity into a wide variety of desired activity patterns. FORCE learning works even though the networks we train are spontaneously chaotic and we leave feedback loops intact and unclamped during learning. Using this approach, we construct networks that produce a wide variety of complex output patterns, input-output transformations that require memory, multiple outputs that can be switched by control inputs, and motor patterns matching human motion capture data. Our results reproduce data on pre-movement activity in motor and premotor cortex, and suggest that synaptic plasticity may be a more rapid and powerful modulator of network activity than generally appreciated. PMID:19709635

  14. Coronal and transition-region Doppler shifts of an active region 3D-MHD model as indicator for the magnetic activity cycle of solar-like stars

    NASA Astrophysics Data System (ADS)

    Bourdin, Philippe A.

    2015-08-01

    For the Sun and solar-like stars, Doppler blueshifts are observed in the hot corona, while in average redshifts are seen in the cooler transition region layer below the corona. This clearly contradicts the idea of a continuous flow-equilibrium starting from a star's atmosphere and forming the stellar wind. To explain this, we implement a 3D-MHD model of the solar corona above an observed active region and use an atomic database to obtain the emission from the million Kelvin hot plasma. The generated EUV-bright loops system from the model compares well to the observed coronal loops. Therefore, we have access to realistic plasma parameters, including the flow dynamics within the active region core, and can derive total spectra as if we look the Sun as a star. We compare the model spectra to actual statistical observations of the Sun taken at different magnetic activity levels. We find characteristic Doppler-shift statistics that can be used to identify the magnetic activity state of the Sun and solar-like stars. This should help to model the variability of such stars by inferring their activity level from total spectra of coronal and transition-region emission lines.

  15. TARPs: Tracked Active Region Patches from SoHO/MDI

    NASA Astrophysics Data System (ADS)

    Turmon, M.; Hoeksema, J. T.; Bobra, M.

    2013-12-01

    We describe progress toward creating a retrospective MDI data product consisting of tracked magnetic features on the scale of solar active regions, abbreviated TARPs (Tracked Active Region Patches). The TARPs are being developed as a backward-looking extension (covering approximately 3500 regions spanning 1996-2010) to the HARP (HMI Active Region Patch) data product that has already been released for HMI (2010-present). Like the HARPs, the MDI TARP data set is designed to be a catalog of active regions (ARs), indexed by a region ID number, analogous to a NOAA AR number, and time. TARPs from MDI are computed based on the 96-minute synoptic magnetograms and pseudo-continuum intensitygrams. As with the related HARP data product, the approximate threshold for significance is 100G. Use of both image types together allows faculae and sunspots to be separated out as sub-classes of activity, in addition to identifying the overall active region that the faculae/sunspots are part of. After being identified in single images, the magnetically-active patches are grouped and tracked from image to image. Merges among growing active regions, as well as faint active regions hovering at the threshold of detection, are handled automatically. Regions are tracked from their inception until they decay within view, or transit off the visible disk. The final data product is indexed by a nominal AR number and time. For each active region and for each time, a bitmap image is stored containing the precise outline of the active region. Additionaly, metadata such as areas and integrated fluxes are stored for each AR and for each time. Because there is a calibration between the HMI and MDI magnetograms (Liu, Hoeksema et al. 2012), it is straightforward to use the same classification and tracking rules for the HARPs (from HMI) and the MDI TARPs. We anticipate that this will allow a consistent catalog spanning both instruments. We envision several uses for the TARP data product, which will be

  16. Active Region Moss: Doppler Shifts from Hinode/EIS Observations

    NASA Technical Reports Server (NTRS)

    Tripathi, Durgesh; Mason, Helen E.; Klimchuk, James A.

    2012-01-01

    Studying the Doppler shifts and the temperature dependence of Doppler shifts in moss regions can help us understand the heating processes in the core of the active regions. In this paper we have used an active region observation recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) onboard Hinode on 12-Dec- 2007 to measure the Doppler shifts in the moss regions. We have distinguished the moss regions from the rest of the active region by defining a low density cut-off as derived by Tripathi et al. (2010). We have carried out a very careful analysis of the EIS wavelength calibration based on the method described in Young, O Dwyer and Mason (2012). For spectral lines having maximum sensitivity between log T = 5.85 and log T = 6.25 K, we find that the velocity distribution peaks at around 0 km/s with an estimated error of 4 km/s. The width of the distribution decreases with temperature. The mean of the distribution shows a blue shift which increases with increasing temperature and the distribution also shows asymmetries towards blue-shift. Comparing these results with observables predicted from different coronal heating models, we find that these results are consistent with both steady and impulsive heating scenarios. Further observational constraints are needed to distinguish between these two heating scenarios.

  17. Determining the solar wind speed above active regions using remote radio-wave observations

    NASA Technical Reports Server (NTRS)

    Fainberg, J.; Stone, R. G.; Bougeret, J.-L.

    1983-01-01

    A new technique has made it possible to measure the velocity of portions of the solar wind during its flow outward from the sun. This analysis utilizes spacecraft (ISEE-3) observations of radio emission generated in regions of the solar wind associated with solar active regions. By tracking the source of these radio waves over periods of days, it is possible to measure the motion of the emission regions. Evidence of solar wind acceleration during this outward flow, consistent with theoretical models, has also been obtained.

  18. The Distribution of Active Force Generators Controls Mitotic Spindle Position

    NASA Astrophysics Data System (ADS)

    Grill, Stephan W.; Howard, Jonathon; Schäffer, Erik; Stelzer, Ernst H. K.; Hyman, Anthony A.

    2003-07-01

    During unequal cell divisions a mitotic spindle is eccentrically positioned before cell cleavage. To determine the basis of the net force imbalance that causes spindle displacement in one-cell Caenorhabditis elegans embryos, we fragmented centrosomes with an ultraviolet laser. Analysis of the mean and variance of fragment speeds suggests that the force imbalance is due to a larger number of force generators pulling on astral microtubules of the posterior aster relative to the anterior aster. Moreover, activation of heterotrimeric guanine nucleotide-binding protein (G protein) α subunits is required to generate these astral forces.

  19. [Do regional and generational differences in attitudes toward "Luck Resource Belief" exist?].

    PubMed

    Murakami, Koshi

    2016-04-01

    This article examines whether belief in superstitions and folklore differs by age and degree of modernization specifically. This study investigated regional and generational differences in attitudes toward "Luck Resource Belief," a notion regarding luck. The 500 Japanese participants in our sample were stratified by place of residence, age, and income. The results reflected gender differences, but not regional or generational differences with regard to the "Luck Resource Belief" scale scores. Based on these results, the hypothesis that the mass media plays a major role in the dissemination of information about superstitions and folklore is discussed in this context. PMID:27180517

  20. Hypergraph-based saliency map generation with potential region-of-interest approximation and validation

    NASA Astrophysics Data System (ADS)

    Liang, Zhen; Fu, Hong; Chi, Zheru; Feng, Dagan

    2012-01-01

    A novel saliency model is proposed in this paper to automatically process images in the similar way as the human visual system which focuses on conspicuous regions that catch human beings' attention. The model combines a hypergraph representation and a partitioning process with potential region-of-interest (p-ROI) approximation and validation. Experimental results demonstrate that the proposed method shows considerable improvement in the performance of saliency map generation.

  1. Nitrite attenuated peroxynitrite and hypochlorite generation in activated neutrophils.

    PubMed

    Ren, Xiaoming; Ding, Yun; Lu, Naihao

    2016-03-15

    Oxidative stress is usually considered as an important factor to the pathogenesis of various diseases. Peroxynitrite (ONOO(-)) and hypochlorite (OCl(-)) are formed in immune cells as a part of the innate host defense system, but excessive reactive oxygen species generation can cause progressive inflammation and tissue damage. It has been proven that through mediating nitric oxide (NO) homeostasis, inorganic nitrite (NO2(-)) shows organ-protective effects on oxidative stress and inflammation. However, the effects of NO2(-) on the function of immune cells were still not clear. The potential role of NO2(-) in modulating ONOO(-) and OCl(-) generation in neutrophil cells was investigated in this study. As an immune cell activator, lipopolysaccharide (LPS) increased both ONOO(-) and OCl(-) production in neutrophils, which was significantly attenuated by NO2(-). NO2(-) reduced superoxide (O2(·-)) generation via a NO-dependent mechanism and increased NO formation in activated neutrophils, suggesting a crucial role of O2(·-) in NO2(-)-mediated reduction of ONOO(-). Moreover, the reduced effect of NO2(-) on OCl(-) production was attributed to that NO2(-) reduced H2O2 production in activated neutrophils without influencing the release of myeloperoxidase (MPO), thus limiting OCl(-) production by MPO/H2O2 system. Therefore, NO2(-) attenuates ONOO(-) and OCl(-) formation in activated neutrophils, opening a new direction to modulate the inflammatory response. PMID:26854590

  2. A Novel Analysis of Acoustic Oscillations in Chromospheric Active Regions

    NASA Astrophysics Data System (ADS)

    Monsue, Teresa; Hill, Frank; Stassun, Keivan G.

    2015-04-01

    A helioseismic analysis of the chromosphere is employed in H-alpha to study how solar flares around active regions affect the behavior of acoustic oscillations. Our analysis deals with flares directly over sunspots, where the region is highly magnetized. In our current study of analyzing these oscillations in the chromosphere we study the temporal evolution of the oscillatory behavior from data taken from the Global Oscillation Network Group (GONG) H-alpha detectors. We investigate the wave behavior across different frequency bands (1 < ν < 8.33 mHz). In order to analyze the frequency bands of the oscillations, our analysis utilizes time series data to create Fourier power spectra of individual pixels spatially resolved and temporally evolved around the flare region; thereby creating a movie of each frequency band. This study entails three active regions, directly over sunspots, in which flaring activity is taking place from two solar flares, which occurred on June 13th and July 12th, 2012. We found that the intensity of the flare has an effect on the oscillations within different frequency bands. A suppression of power was observed in dark anomalous structures across the total frequency bands and in other regions there was an observed boost in power due to flaring activity. We find that, in the heart of all three regions, the low-frequency power (˜1-2 mHz) is substantially enhanced immediately prior to and after the flare, and that power at all frequencies up to 8 mHz is depleted at flare maximum. This depletion is both frequency and time dependent, which probably reflects the changing depths visible during the flare in the bandpass of the filter. These variations are not observed outside the flaring region. The depletion may indicate that acoustic energy is being converted into thermal energy at flare maximum, while the low-frequency enhancement may arise from an instability in the chromosphere and provide an early warning of the flare onset.

  3. Variegation of comet 67P/Churyumov-Gerasimenko in regions showing activity

    NASA Astrophysics Data System (ADS)

    Oklay, N.; Vincent, J.-B.; Fornasier, S.; Pajola, M.; Besse, S.; Davidsson, B. J. R.; Lara, L. M.; Mottola, S.; Naletto, G.; Sierks, H.; Barucci, A. M.; Scholten, F.; Preusker, F.; Pommerol, A.; Masoumzadeh, N.; Lazzarin, M.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; A'Hearn, M. F.; Bertaux, J.-L.; Bertini, I.; Bodewits, D.; Cremonese, G.; Da Deppo, V.; Debei, S.; De Cecco, M.; Fulle, M.; Groussin, O.; Gutiérrez, P. J.; Güttler, C.; Hall, I.; Hofmann, M.; Hviid, S. F.; Ip, W.-H.; Jorda, L.; Keller, H. U.; Knollenberg, J.; Kovacs, G.; Kramm, J.-R.; Kührt, E.; Küppers, M.; Lin, Z.-Y.; Lopez Moreno, J. J.; Marzari, F.; Moreno, F.; Shi, X.; Thomas, N.; Toth, I.; Tubiana, C.

    2016-02-01

    Aims.We carried out an investigation of the surface variegation of comet 67P/Churyumov-Gerasimenko, the detection of regions showing activity, the determination of active and inactive surface regions of the comet with spectral methods, and the detection of fallback material. Methods: We analyzed multispectral data generated with Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) narrow angle camera (NAC) observations via spectral techniques, reflectance ratios, and spectral slopes in order to study active regions. We applied clustering analysis to the results of the reflectance ratios, and introduced the new technique of activity thresholds to detect areas potentially enriched in volatiles. Results: Local color inhomogeneities are detected over the investigated surface regions. Active regions, such as Hapi, the active pits of Seth and Ma'at, the clustered and isolated bright features in Imhotep, the alcoves in Seth and Ma'at, and the large alcove in Anuket, have bluer spectra than the overall surface. The spectra generated with OSIRIS NAC observations are dominated by cometary emissions of around 700 nm to 750 nm as a result of the coma between the comet's surface and the camera. One of the two isolated bright features in the Imhotep region displays an absorption band of around 700 nm, which probably indicates the existence of hydrated silicates. An absorption band with a center between 800-900 nm is tentatively observed in some regions of the nucleus surface. This absorption band can be explained by the crystal field absorption of Fe2+, which is a common spectral feature seen in silicates.

  4. On the Active Region Bright Grains Observed in the Transition Region Imaging Channels of IRIS

    NASA Astrophysics Data System (ADS)

    Skogsrud, H.; Rouppe van der Voort, L.; De Pontieu, B.

    2016-02-01

    The Interface Region Imaging Spectrograph (IRIS) provides spectroscopy and narrow band slit-jaw (SJI) imaging of the solar chromosphere and transition region at unprecedented spatial and temporal resolutions. Combined with high-resolution context spectral imaging of the photosphere and chromosphere as provided by the Swedish 1 m Solar Telescope (SST), we can now effectively trace dynamic phenomena through large parts of the solar atmosphere in both space and time. IRIS SJI 1400 images from active regions, which primarily sample the transition region with the Si iv 1394 and 1403 Å lines, reveal ubiquitous bright “grains” which are short-lived (two to five minute) bright roundish small patches of sizes 0.″5-1.″7 that generally move limbward with velocities up to about 30 km s-1. In this paper, we show that many bright grains are the result of chromospheric shocks impacting the transition region. These shocks are associated with dynamic fibrils (DFs), most commonly observed in Hα. We find that the grains show the strongest emission in the ascending phase of the DF, that the emission is strongest toward the top of the DF, and that the grains correspond to a blueshift and broadening of the Si iv lines. We note that the SJI 1400 grains can also be observed in the SJI 1330 channel which is dominated by C ii lines. Our observations show that a significant part of the active region transition region dynamics is driven from the chromosphere below rather than from coronal activity above. We conclude that the shocks that drive DFs also play an important role in the heating of the upper chromosphere and lower transition region.

  5. Skylab observations of X-ray loops connecting separate active regions. [solar activity

    NASA Technical Reports Server (NTRS)

    Chase, R. C.; Krieger, A. S.; Svestka, Z.; Vaiana, G. S.

    1976-01-01

    One hundred loops interconnecting 94 separate active solar regions detectable in soft X-rays were identified during the Skylab mission. While close active regions are commonly interconnected with loops, the number of such interconnections decreases steeply for longer distances; the longest interconnecting loop observed in the Skylab data connected regions separated by 37 deg. Several arguments are presented which support the point of view that this is the actual limit of the size of magnetic interconnections between active regions. No sympathetic flares could be found in the interconnected regions. These results cast doubt on the hypothesis that accelerated particles can be guided in interconnecting loops from one active region to another over distances of 100 deg or more and eventually produce sympathetic flares in them.

  6. Socioeconomic and regional differences in active transportation in Brazil

    PubMed Central

    de Sá, Thiago Hérick; Pereira, Rafael Henrique Moraes; Duran, Ana Clara; Monteiro, Carlos Augusto

    2016-01-01

    ABSTRACT OBJECTIVE To present national estimates regarding walking or cycling for commuting in Brazil and in 10 metropolitan regions. METHODS By using data from the Health section of 2008’s Pesquisa Nacional por Amostra de Domicílio (Brazil’s National Household Sample Survey), we estimated how often employed people walk or cycle to work, disaggregating our results by sex, age range, education level, household monthly income per capita, urban or rural address, metropolitan regions, and macro-regions in Brazil. Furthermore, we estimated the distribution of this same frequency according to quintiles of household monthly income per capita in each metropolitan region of the country. RESULTS A third of the employed men and women walk or cycle from home to work in Brazil. For both sexes, this share decreases as income and education levels rise, and it is higher among younger individuals, especially among those living in rural areas and in the Northeast region of the country. Depending on the metropolitan region, the practice of active transportation is two to five times more frequent among low-income individuals than among high-income individuals. CONCLUSIONS Walking or cycling to work in Brazil is most frequent among low-income individuals and the ones living in less economically developed areas. Active transportation evaluation in Brazil provides important information for public health and urban mobility policy-making PMID:27355465

  7. Influence of air-jet vortex generator diameter on separation region

    NASA Astrophysics Data System (ADS)

    Szwaba, Ryszard

    2013-08-01

    Control of shock wave and boundary layer interaction continues to attract a lot of attention. In recent decades several methods of interaction control have been investigated. The research has mostly concerned solid (vane type) vortex generators and transpiration methods of suction and blowing. This investigation concerns interaction control using air-jets to generate streamwise vortices. The effectiveness of air-jet vortex generators in controlling separation has been proved in a previous research. The present paper focuses on the influence of the vortex generator diameter on the separation region. It presents the results of experimental investigations and provides new guidelines for the design of air-jet vortex generators to obtain more effective separation control.

  8. IFLA General Conference, 1987. Division of Regional Activities. Papers.

    ERIC Educational Resources Information Center

    International Federation of Library Associations, The Hague (Netherlands).

    Six of the seven papers in this collection focus on regional library activities in Africa, Asia and Oceania, and Latin America and the Caribbean: (1) "Libraries and Information Services in a Changing World: The Challenges African Information Services Face at the End of the 1980s" (Dejen Abate, Ethiopia); (2) "The Computer and Knowledge Information…

  9. A solar cycle timing predictor - The latitude of active regions

    NASA Technical Reports Server (NTRS)

    Schatten, Kenneth H.

    1990-01-01

    A 'Spoerer butterfly' method is used to examine solar cycle 22. It is shown from the latitude of active regions that the cycle can now be expected to peak near November 1989 + or - 8 months, basically near the latter half of 1989.

  10. SNS Devices With Pinhole-Defined Active Regions

    NASA Technical Reports Server (NTRS)

    Hunt, Brian D.; Barner, Jeffrey B.

    1996-01-01

    Superconductor/normal conductor/superconductor (SNS) microbridge devices with pinhole-defined active regions undergoing development. Device includes thin, electrically insulating layer deposited epitaxially, with controlled formation of pinholes, on one of two superconducting layers. Normally conducting metal deposited epitaxially in pinholes and on insulating layer, forming electrical contact between two superconducting layers. Junction resistances and maximum junction voltages expected to be increased.

  11. Early life stress affects limited regional brain activity in depression

    PubMed Central

    Du, Lian; Wang, Jingjie; Meng, Ben; Yong, Na; Yang, Xiangying; Huang, Qingling; Zhang, Yan; Yang, Lingling; Qu, Yuan; Chen, Zhu; Li, Yongmei; Lv, Fajin; Hu, Hua

    2016-01-01

    Early life stress (ELS) can alter brain function and increases the risk of major depressive disorder (MDD) in later life. This study investigated whether ELS contributes to differences in regional brain activity between MDD patients and healthy controls (HC), as measured by amplitude of low-frequency fluctuation (ALFF)/fractional (f)ALFF. Eighteen first-episode, treatment-naïve MDD patients and HC were assessed with the Childhood Trauma Questionnaire and resting-state functional magnetic resonance imaging. We compared ALFF/fALFF between MDD patients and HC, with or without controlling for ELS, and determined whether ELS level was correlated with regional brain activity in each group. After regressing out ELS, we found that ALFF increased in bilateral amygdala and left orbital/cerebellum, while fALFF decreased in left inferior temporal and right middle frontal gyri in MDD patients relative to controls. ELS positively correlated with regional activity in the left cerebellum in MDD and in the right post-central/inferior temporal/superior frontal cingulate, inferior frontal gyrus and bilateral cerebellum in HC. Our findings indicate that there is only very limited region showing correlation between ELS and brain activity in MDD, while diverse areas in HC, suggesting ELS has few impacts on MDD patients. PMID:27138376

  12. Urban, Rural, and Regional Variations in Physical Activity

    ERIC Educational Resources Information Center

    Martin, Sarah Levin; Kirkner, Gregory J.; Mayo, Kelly; Matthews, Charles E.; Durstine, J. Larry; Hebert, James R.

    2005-01-01

    Purpose: There is some speculation about geographic differences in physical activity (PA) levels. We examined the prevalence of physical inactivity (PIA) and whether US citizens met the recommended levels of PA across the United States. In addition, the association between PIA/PA and degree of urbanization in the 4 main US regions (Northeast,…

  13. Unwinding motion of a twisted active region filament

    SciTech Connect

    Yan, X. L.; Xue, Z. K.; Kong, D. F.; Liu, J. H.; Xu, C. L.

    2014-12-10

    To better understand the structures of active region filaments and the eruption process, we study an active region filament eruption in active region NOAA 11082 in detail on 2010 June 22. Before the filament eruption, the opposite unidirectional material flows appeared in succession along the spine of the filament. The rising of the filament triggered two B-class flares at the upper part of the filament. As the bright material was injected into the filament from the sites of the flares, the filament exhibited a rapid uplift accompanying the counterclockwise rotation of the filament body. From the expansion of the filament, we can see that the filament consisted of twisted magnetic field lines. The total twist of the filament is at least 5π obtained by using a time slice method. According to the morphology change during the filament eruption, it is found that the active region filament was a twisted flux rope and its unwinding motion was like a solar tornado. We also find that there was a continuous magnetic helicity injection before and during the filament eruption. It is confirmed that magnetic helicity can be transferred from the photosphere to the filament. Using the extrapolated potential fields, the average decay index of the background magnetic fields over the filament is 0.91. Consequently, these findings imply that the mechanism of solar filament eruption could be due to the kink instability and magnetic helicity accumulation.

  14. Inferred flows of electric currents in solar active regions

    NASA Technical Reports Server (NTRS)

    Ding, Y. J.; Hong, Q. F.; Hagyard, M. J.; Deloach, A. C.

    1985-01-01

    Techniques to identify sources of major current systems in active regions and their channels of flow are explored. Measured photospheric vector magnetic fields together with high resolution white light and H-alpha photographs provide the data base to derive the current systems in the photosphere and chromosphere of a solar active region. Simple mathematical constructions of active region fields and currents are used to interpret these data under the assumptions that the fields in the lower atmosphere (below 200 km) may not be force free but those in the chromosphere and higher are. The results obtained for the complex active region AR 2372 are: (1) Spots exhibiting significant spiral structure in the penumbral filaments were the source of vertical currents at the photospheric surface; (2) Magnetic neutral lines where the transverse magnetic field was strongly sheared were channels along which a strong current system flowed; (3) The inferred current systems produced a neutral sheet and oppositely-flowing currents in the area of the magnetic delta configuration that was the site of flaring.

  15. Heating of active region cores: Impulsive or steady?

    NASA Astrophysics Data System (ADS)

    Tripathi, Durgesh

    The question of active region heating has proven to be highly challenging since its discovery in 1940s. The recent observational facilities have shed new lights towards the understanding of this problem. In this paper we review some of the new measurements to study the heating mechanisms in the hot core loops of active regions using the observations recorded by Solar Ultraviolet Measurements of Emitted Radiation (SUMER) onboard SoHO and the Extreme-ultraviolet Imaging Spectrometer (EIS) aboard Hinode. These new measurements show that the properties of hot core loops are consistent with by impulsive heating -- low frequency nanoflare - scenario. However, the evidences are not strong enough to rule-out steady heating completely. Further measurement using better spectral resolution and temperature coverage is required, which will be provided by Interface Region Imaging Spectrometer (IRIS) and Solar-C in near future.

  16. Evolution of two Flaring Active Regions With CME Association

    NASA Astrophysics Data System (ADS)

    Thalmann, J. K.; Wiegelmann, T.

    2008-12-01

    We study the coronal magnetic field structure of two active regions, one during solar activity minimum (June 2007) and another one during a more active time (January 2004). The temporal evolution was explored with the help of nonlinear force-free coronal magnetic field extrapolations of SOLIS/VSM and NAOJ/SFT photospheric vector magnetograms. We study the active region NOAA 10960 observed on 2007 June 7 with three SOLIS/VSM snapshots taken during a small C1.0 flare of time cadence 10 minutes and six snapshots during a quiet period. The total magnetic energy in the active region was approximately 3 × 1025 J. Before the flare the free magnetic energy was about 5~% of the potential field energy. A part of this excess energy was released during the flare, producing almost a potential configuration at the beginning of the quiet period. The return to an almost potential structure can be assigned to a CME as recorded by the SoHO/LASCO instrument on 2007 June 07 around 10 minutes after the flare peaked, so that whatever magnetic helicity was bodily removed from the structure. This was compared with active region 10540 observed on 2004 January 18 -- 21, which was analyzed with the help of vector magnetograph data from the Solar Flare Telescope in Japan of time cadence of about 1 day. The free energy was Efree≈ 66~% of the total energy which was sufficiently high to power a M6.1 flare on January 20, which was associated with a CME 20 minutes later. The activity of AR 10540 was significantly higher than for AR 10960, as was the total magnetic energy. Furthermore, we found the common feature that magnetic energy accumulates before the flare/CME and a significant part of the excess energy is released during the eruption.

  17. Doppler Shifts in Active Region Moss Using SOHO/SUMER

    NASA Astrophysics Data System (ADS)

    Winebarger, Amy; Tripathi, Durgesh; Mason, Helen E.; Del Zanna, Giulio

    2013-04-01

    The velocity of the plasma at the footpoint of hot loops in active region cores can be used to discriminate between different heating frequencies. Velocities on the order of a few kilometers per second would indicate low-frequency heating on sub-resolution strands, while velocities close to zero would indicate high-frequency (steady) heating. To discriminate between these two values requires accurate velocity measurements; previous velocity measurements suffer from large uncertainties, mainly due to the lack of an absolute wavelength reference scale. In this paper, we determine the velocity in the loop footpoints using observations from Solar Ultraviolet Measurements of Emitted Radiation (SUMER) on Solar and Heliospheric Observatory. We use neutral spectral lines to determine the wavelength scale of the observations with an uncertainty in the absolute velocity of <3.5 km s-1 and co-aligned Transition Region and Coronal Explorer (TRACE) images to identify footpoint regions. We studied three different active regions and found average redshifts in the Ne VIII 770 Å emission line (formed at 6 × 105 K) of 5.17 ± 5.37 km s-1 and average redshifts in the C IV 1548 and 1550 Å emission lines (formed at 1 × 105 K) of 13.94 ± 4.93 km s-1 and 14.91 ± 6.09 km s-1, respectively. We find no correlation between the brightness in the spectral line and the measured velocity, nor do we find correlation between the Ne VIII and C IV velocities measured co-spatially and co-temporally. SUMER scanned two of the active regions twice; in those active regions we find positive correlation between the co-spatial velocities measured during the first and second scans. These results provide definitive and quantitative measurements for comparisons with simulations of different coronal heating mechanisms.

  18. Active Interrogation Using Electronic Neutron Generators for Nuclear Safeguards Applications

    NASA Astrophysics Data System (ADS)

    Chichester, D. L.; Seabury, E. H.

    2009-03-01

    Active interrogation, a measurement technique which uses a radiation source to probe materials and generate unique signatures useful for characterizing those materials, is a powerful tool for assaying special nuclear material. The most commonly used technique for performing active interrogation is to use an electronic neutron generator as the probe radiation source. Exploiting the unique operating characteristics of these devices, including their monoenergetic neutron emissions and their ability to operate in pulsed modes, presents a number of options for performing prompt and delayed signature analyses using both photon and neutron sensors. A review of literature in this area shows multiple applications of the active neutron interrogation technique for performing nuclear nonproliferation measurements. Some examples include measuring the plutonium content of spent fuel, assaying plutonium residue in spent fuel hull claddings, assaying plutonium in aqueous fuel reprocessing process streams, and assaying nuclear fuel reprocessing facility waste streams to detect and quantify fissile material. This paper discusses the historical use of this technique and examines its context within the scope and challenges of next-generation nuclear fuel cycles and advanced concept nuclear fuel cycle facilities.

  19. Active Interrogation Using Electronic Neutron Generators for Nuclear Safeguards Applications

    SciTech Connect

    David L. Chichester; Edward H. Seabury

    2008-08-01

    Active interrogation, a measurement technique which uses a radiation source to probe materials and generate unique signatures useful for characterizing those materials, is a powerful tool for assaying special nuclear material. The most commonly used technique for performing active interrogation is to use an electronic neutron generator as the probe radiation source. Exploiting the unique operating characteristics of these devices, including their monoenergetic neutron emissions and their ability to operate in pulsed modes, presents a number of options for performing prompt and delayed signature analyses using both photon and neutron sensors. A review of literature in this area shows multiple applications of the active neutron interrogation technique for performing nuclear nonproliferation measurements. Some examples include measuring the plutonium content of spent fuel, assaying plutonium residue in spent fuel hull claddings, assaying plutonium in aqueous fuel reprocessing process streams, and assaying nuclear fuel reprocessing facility waste streams to detect and quantify fissile material. This paper discusses the historical use of this technique and examines its context within the scope and challenges of next-generation nuclear fuel cycles and advanced concept nuclear fuel cycle facilities.

  20. ESTIMATING LIGHTNING-GENERATED NOX EMISSIONS FOR REGIONAL AIR POLLUTION MODELS

    EPA Science Inventory

    The specification of natural NOx emissions may be important for regional-scale air pollution modeling. ow that a national lightning detection network is operating, it is possible to make episodic estimates of lightning generated NOx emissions and to resolve these emissions to fin...

  1. Dependence of hydropower energy generation on forests in the Amazon Basin at local and regional scales.

    PubMed

    Stickler, Claudia M; Coe, Michael T; Costa, Marcos H; Nepstad, Daniel C; McGrath, David G; Dias, Livia C P; Rodrigues, Hermann O; Soares-Filho, Britaldo S

    2013-06-01

    Tropical rainforest regions have large hydropower generation potential that figures prominently in many nations' energy growth strategies. Feasibility studies of hydropower plants typically ignore the effect of future deforestation or assume that deforestation will have a positive effect on river discharge and energy generation resulting from declines in evapotranspiration (ET) associated with forest conversion. Forest loss can also reduce river discharge, however, by inhibiting rainfall. We used land use, hydrological, and climate models to examine the local "direct" effects (through changes in ET within the watershed) and the potential regional "indirect" effects (through changes in rainfall) of deforestation on river discharge and energy generation potential for the Belo Monte energy complex, one of the world's largest hydropower plants that is currently under construction on the Xingu River in the eastern Amazon. In the absence of indirect effects of deforestation, simulated deforestation of 20% and 40% within the Xingu River basin increased discharge by 4-8% and 10-12%, with similar increases in energy generation. When indirect effects were considered, deforestation of the Amazon region inhibited rainfall within the Xingu Basin, counterbalancing declines in ET and decreasing discharge by 6-36%. Under business-as-usual projections of forest loss for 2050 (40%), simulated power generation declined to only 25% of maximum plant output and 60% of the industry's own projections. Like other energy sources, hydropower plants present large social and environmental costs. Their reliability as energy sources, however, must take into account their dependence on forests. PMID:23671098

  2. Anemone structure of Active Region NOAA 10798 and related geo-effective flares/ CMEs

    NASA Astrophysics Data System (ADS)

    Asai, A.; Ishii, T. T.; Shibata, K.; Gopalswamy, N.

    2006-08-01

    Introduction: We report the evolution and the coronal features of an active region NOAA 10798, and the related magnetic storms. Method: We examined in detail the photospheric and coronal features of the active region by using observational data in soft X-rays, in extreme ultraviolet images, and in magnetogram obtained with GOES, SOHO satellites. We also examined the interplanetary disturbances from the ACE data. Results: This active region was located in the middle of a small coronal hole, and generated 3 M-class flares. The flares are associated with high speed CMEs up to 2000 km/s. The interplanetary disturbances also show a structure with southward strong magnetic field. These produced a magnetic storm on 2005 August 24. Conclusions: The anemone structure may play a role for producing the high-speed and geo-effective CMEs even the near limb locations.

  3. Patterns of Activity Revealed by a Time Lag Analysis of a Model Active Region

    NASA Astrophysics Data System (ADS)

    Bradshaw, Stephen; Viall, Nicholeen

    2016-05-01

    We investigate the global activity patterns predicted from a model active region heated by distributions of nanoflares that have a range of average frequencies. The activity patterns are manifested in time lag maps of narrow-band instrument channel pairs. We combine an extrapolated magnetic skeleton with hydrodynamic and forward modeling codes to create a model active region, and apply the time lag method to synthetic observations. Our aim is to recover some typical properties and patterns of activity observed in active regions. Our key findings are: 1. Cooling dominates the time lag signature and the time lags between the channel pairs are generally consistent with observed values. 2. Shorter coronal loops in the core cool more quickly than longer loops at the periphery. 3. All channel pairs show zero time lag when the line-of-sight passes through coronal loop foot-points. 4. There is strong evidence that plasma must be re-energized on a time scale comparable to the cooling timescale to reproduce the observed coronal activity, but it is likely that a relatively broad spectrum of heating frequencies operates across active regions. 5. Due to their highly dynamic nature, we find nanoflare trains produce zero time lags along entire flux tubes in our model active region that are seen between the same channel pairs in observed active regions.

  4. Active sonar, beaked whales and European regional policy.

    PubMed

    Dolman, Sarah J; Evans, Peter G H; Notarbartolo-di-Sciara, Giuseppe; Frisch, Heidrun

    2011-01-01

    Various reviews, resolutions and guidance from international and regional fora have been produced in recent years that acknowledge the significance of marine noise and its potential impacts on cetaceans. Within Europe, ACCOBAMS and ASCOBANS have shown increasing attention to the issue. The literature highlights concerns surrounding the negative impacts of active sonar on beaked whales in particular, where concerns primarily relate to the use of mid-frequency active sonar (1-10kHz), as used particularly in military exercises. The authors review the efforts that European regional policies have undertaken to acknowledge and manage possible negative impacts of active sonar and how these might assist the transition from scientific research to policy implementation, including effective management and mitigation measures at a national level. PMID:20451221

  5. Sensitivity of Regional Hydropower Generation to the Projected Changes in Future Watershed Hydrology

    NASA Astrophysics Data System (ADS)

    Kao, S. C.; Naz, B. S.; Gangrade, S.

    2015-12-01

    Hydropower is a key contributor to the renewable energy portfolio due to its established development history and the diverse benefits it provides to the electric power systems. With the projected change in the future watershed hydrology, including shift of snowmelt timing, increasing occurrence of extreme precipitation, and change in drought frequencies, there is a need to investigate how the regional hydropower generation may change correspondingly. To evaluate the sensitivity of watershed storage and hydropower generation to future climate change, a lumped Watershed Runoff-Energy Storage (WRES) model is developed to simulate the annual and seasonal hydropower generation at various hydropower areas in the United States. For each hydropower study area, the WRES model use the monthly precipitation and naturalized (unregulated) runoff as inputs to perform a runoff mass balance calculation for the total monthly runoff storage in all reservoirs and retention facilities in the watershed, and simulate the monthly regulated runoff release and hydropower generation through the system. The WRES model is developed and calibrated using the historic (1980-2009) monthly precipitation, runoff, and generation data, and then driven by a large set of dynamically- and statistically-downscaled Coupled Model Intercomparison Project Phase 5 climate projections to simulate the change of watershed storage and hydropower generation under different future climate scenarios. The results among different hydropower regions, storage capacities, emission scenarios, and timescales are compared and discussed in this study.

  6. THE EVOLUTION OF DARK CANOPIES AROUND ACTIVE REGIONS

    SciTech Connect

    Wang, Y.-M.; Robbrecht, E.; Muglach, K. E-mail: eva.robbrecht@oma.be

    2011-05-20

    As observed in spectral lines originating from the chromosphere, transition region, and low corona, active regions are surrounded by an extensive 'circumfacular' area which is darker than the quiet Sun. We examine the properties of these dark moat- or canopy-like areas using Fe IX 17.1 nm images and line-of-sight magnetograms from the Solar Dynamics Observatory. The 17.1 nm canopies consist of fibrils (horizontal fields containing extreme-ultraviolet-absorbing chromospheric material) clumped into featherlike structures. The dark fibrils initially form a quasiradial or vortical pattern as the low-lying field lines fanning out from the emerging active region connect to surrounding network and intranetwork elements of opposite polarity. The area occupied by the 17.1 nm fibrils expands as supergranular convection causes the active-region flux to spread into the background medium; the outer boundary of the dark canopy stabilizes where the diffusing flux encounters a unipolar region of opposite sign. The dark fibrils tend to accumulate in regions of weak longitudinal field and to become rooted in mixed-polarity flux. To explain the latter observation, we note that the low-lying fibrils are more likely to interact with small loops associated with weak, opposite-polarity flux elements in close proximity, than with high loops anchored inside strong unipolar network flux. As a result, the 17.1 nm fibrils gradually become concentrated around the large-scale polarity inversion lines (PILs), where most of the mixed-polarity flux is located. Systematic flux cancellation, assisted by rotational shearing, removes the field component transverse to the PIL and causes the fibrils to coalesce into long PIL-aligned filaments.

  7. Patterns of Activity in a Global Model of a Solar Active Region

    NASA Astrophysics Data System (ADS)

    Bradshaw, S. J.; Viall, N. M.

    2016-04-01

    In this work we investigate the global activity patterns predicted from a model active region heated by distributions of nanoflares that have a range of frequencies. What differs is the average frequency of the distributions. The activity patterns are manifested in time lag maps of narrow-band instrument channel pairs. We combine hydrodynamic and forward modeling codes with a magnetic field extrapolation to create a model active region and apply the time lag method to synthetic observations. Our aim is not to reproduce a particular set of observations in detail, but to recover some typical properties and patterns observed in active regions. Our key findings are the following. (1) Cooling dominates the time lag signature and the time lags between the channel pairs are generally consistent with observed values. (2) Shorter coronal loops in the core cool more quickly than longer loops at the periphery. (3) All channel pairs show zero time lag when the line of sight passes through coronal loop footpoints. (4) There is strong evidence that plasma must be re-energized on a timescale comparable to the cooling timescale to reproduce the observed coronal activity, but it is likely that a relatively broad spectrum of heating frequencies are operating across active regions. (5) Due to their highly dynamic nature, we find nanoflare trains produce zero time lags along entire flux tubes in our model active region that are seen between the same channel pairs in observed active regions.

  8. Bioreductively Activated Reactive Oxygen Species (ROS) Generators as MRSA Inhibitors.

    PubMed

    Khodade, Vinayak S; Sharath Chandra, Mallojjala; Banerjee, Ankita; Lahiri, Surobhi; Pulipeta, Mallikarjuna; Rangarajan, Radha; Chakrapani, Harinath

    2014-07-10

    The number of cases of drug resistant Staphylococcus aureus infections is on the rise globally and new strategies to identify drug candidates with novel mechanisms of action are in urgent need. Here, we report the synthesis and evaluation of a series of benzo[b]phenanthridine-5,7,12(6H)-triones, which were designed based on redox-active natural products. We find that the in vitro inhibitory activity of 6-(prop-2-ynyl)benzo[b]phenanthridine-5,7,12(6H)-trione (1f) against methicillin-resistant Staphylococcus aureus (MRSA), including a panel of patient-derived strains, is comparable or better than vancomycin. We show that the lead compound generates reactive oxygen species (ROS) in the cell, contributing to its antibacterial activity. PMID:25050164

  9. The evolution and orientation of early cycle 22 active regions

    NASA Technical Reports Server (NTRS)

    Cannon, Anne T.; Marquette, William H.

    1991-01-01

    The evolution of six major active regions which appeared during the first phase of the present solar cycle (cycle 22) has been studied. It was found that the northern hemisphere regions exhibited a broad range of evolutionary behavior in which the commonly accepted 'normal pattern' (whereby the follower flux moves preferentially polewards ahead of the leader flux) is represented at one end of the range. At the other end of the range, the leader flux is displaced polewards of the follower flux. In the latter cases equatorward extensions of the polar coronal hole are noted.

  10. 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.

  11. Extreme storm activity in North Atlantic and European region

    NASA Astrophysics Data System (ADS)

    Vyazilova, N.

    2010-09-01

    The extreme storm activity study over North Atlantic and Europe includes the analyses of extreme cyclone (track number, integral cyclonic intensity) and extreme storm (track number) during winter and summer seasons in the regions: 1) 55°N-80N, 50°W-70°E; 2) 30°N-55°N, 50°W-70°E. Extreme cyclones were selected based on cyclone centre pressure (P<=970 mbar). Extreme storms were selected from extreme cyclones based on wind velocity on 925 mbar. The Bofort scala was used for this goal. Integral cyclonic intensity (for region) includes the calculation cyclone centers number and sum of MSLP anomalies in cyclone centers. The analyses based on automated cyclone tracking algorithm, 6-hourly MSLP and wind data (u and v on 925 gPa) from the NCEP/NCAR reanalyses from January 1948 to March 2010. The comparision of mean, calculated for every ten years, had shown, that in polar region extreme cyclone and storm track number, and integral cyclonic intensity gradually increases and have maximum during last years (as for summer, as for winter season). Every ten years means for summer season are more then for winter season, as for polar, as for tropical region. Means (ten years) for tropical region are significance less then for polar region.

  12. Indole generates quiescent and metabolically active Escherichia coli cultures.

    PubMed

    Chen, Chih-Chin; Walia, Rupali; Mukherjee, Krishna J; Mahalik, Subhashree; Summers, David K

    2015-04-01

    An inherent problem with bacterial cell factories used to produce recombinant proteins or metabolites is that resources are channeled into unwanted biomass as well as product. Over several years, attempts have been made to increase efficiency by unlinking biomass and product generation. One example was the quiescent cell (Q-Cell) expression system that generated non-growing but metabolically active Escherichia coli by over-expressing a regulatory RNA (Rcd) in a defined genetic background. Although effective at increasing the efficiency with which resources are converted to product, the technical complexity of the Rcd-based Q-Cell system limited its use. We describe here an alternative method for generating Q-Cells by the direct addition of indole, or related indole derivatives, to the culture medium of an E. coli strain carrying defined mutations in the hns gene. This simple and effective approach is shown to be functional in both shake-flask and fermenter culture. The cells remain metabolically active and analysis of their performance in the fermenter suggests that they may be particularly suitable for the production of cellular metabolites. PMID:25594833

  13. Radiation therapy generates platelet-activating factor agonists

    PubMed Central

    Sahu, Ravi P.; Harrison, Kathleen A.; Weyerbacher, Jonathan; Murphy, Robert C.; Konger, Raymond L.; Garrett, Joy Elizabeth; Chin-Sinex, Helen Jan; Johnston, Michael Edward; Dynlacht, Joseph R.; Mendonca, Marc; McMullen, Kevin; Li, Gengxin; Spandau, Dan F.; Travers, Jeffrey B.

    2016-01-01

    Pro-oxidative stressors can suppress host immunity due to their ability to generate oxidized lipid agonists of the platelet-activating factor-receptor (PAF-R). As radiation therapy also induces reactive oxygen species, the present studies were designed to define whether ionizing radiation could generate PAF-R agonists and if these lipids could subvert host immunity. We demonstrate that radiation exposure of multiple tumor cell lines in-vitro, tumors in-vivo, and human subjects undergoing radiation therapy for skin tumors all generate PAF-R agonists. Structural characterization of radiation-induced PAF-R agonistic activity revealed PAF and multiple oxidized glycerophosphocholines that are produced non-enzymatically. In a murine melanoma tumor model, irradiation of one tumor augmented the growth of the other (non-treated) tumor in a PAF-R-dependent process blocked by a cyclooxygenase-2 inhibitor. These results indicate a novel pathway by which PAF-R agonists produced as a byproduct of radiation therapy could result in tumor treatment failure, and offer important insights into potential therapeutic strategies that could improve the overall antitumor effectiveness of radiation therapy regimens. PMID:26959112

  14. Radiation therapy generates platelet-activating factor agonists.

    PubMed

    Sahu, Ravi P; Harrison, Kathleen A; Weyerbacher, Jonathan; Murphy, Robert C; Konger, Raymond L; Garrett, Joy Elizabeth; Chin-Sinex, Helen Jan; Johnston, Michael Edward; Dynlacht, Joseph R; Mendonca, Marc; McMullen, Kevin; Li, Gengxin; Spandau, Dan F; Travers, Jeffrey B

    2016-04-12

    Pro-oxidative stressors can suppress host immunity due to their ability to generate oxidized lipid agonists of the platelet-activating factor-receptor (PAF-R). As radiation therapy also induces reactive oxygen species, the present studies were designed to define whether ionizing radiation could generate PAF-R agonists and if these lipids could subvert host immunity. We demonstrate that radiation exposure of multiple tumor cell lines in-vitro, tumors in-vivo, and human subjects undergoing radiation therapy for skin tumors all generate PAF-R agonists. Structural characterization of radiation-induced PAF-R agonistic activity revealed PAF and multiple oxidized glycerophosphocholines that are produced non-enzymatically. In a murine melanoma tumor model, irradiation of one tumor augmented the growth of the other (non-treated) tumor in a PAF-R-dependent process blocked by a cyclooxygenase-2 inhibitor. These results indicate a novel pathway by which PAF-R agonists produced as a byproduct of radiation therapy could result in tumor treatment failure, and offer important insights into potential therapeutic strategies that could improve the overall antitumor effectiveness of radiation therapy regimens. PMID:26959112

  15. Armenia as a Regional Centre for Astronomy for Development activities

    NASA Astrophysics Data System (ADS)

    Mickaelian, A.

    2015-03-01

    The Byurakan Astrophysical Observatory (BAO, Armenia, http://www.bao.am) are among the candidate IAU Regional Nodes for Astronomy for Development activities. It is one of the main astronomical centers of the former Soviet Union and the Middle East region. At present there are 48 qualified researchers at BAO, including six Doctors of Science and 30 PhDs. Five important observational instruments are installed at BAO, the larger ones being 2.6m Cassegrain (ZTA-2.6) and 1m Schmidt (the one that provided the famous Markarian survey). BAO is regarded as a national scientific-educational center, where a number of activities are being organized, such as: international conferences (4 IAU symposia and 1 IAU colloquium, JENAM-2007, etc.), small workshops and discussions, international summer schools (1987, 2006, 2008 and 2010), and Olympiads. BAO collaborates with scientists from many countries. The Armenian Astronomical Society (ArAS, http://www.aras.am/) is an NGO founded in 2001; it has 93 members and it is rather active in the organization of educational, amateur, popular, promotional and other matters. The Armenian Virtual Observatory (ArVO, http://www.aras.am/Arvo/arvo.htm) is one of the 17 national VO projects forming the International Virtual Observatories Alliance (IVOA) and is the only VO project in the region serving also for educational purposes. A number of activities are planned, such as management, coordination and evaluation of the IAU programs in the area of development and education, establishment of the new IAU endowed lectureship program and organization of seminars and public lectures, coordination and initiation of fundraising activities for astronomy development, organization of regional scientific symposia, conferences and workshops, support to Galileo Teacher Training Program (GTTP), production/publication of educational and promotional materials, etc.

  16. Studies of aerothermal loads generated in regions of shock/shock interaction in hypersonic flow

    NASA Technical Reports Server (NTRS)

    Holden, Michael S.; Moselle, John R.; Lee, Jinho

    1991-01-01

    Experimental studies were conducted to examine the aerothermal characteristics of shock/shock/boundary layer interaction regions generated by single and multiple incident shocks. The presented experimental studies were conducted over a Mach number range from 6 to 19 for a range of Reynolds numbers to obtain both laminar and turbulent interaction regions. Detailed heat transfer and pressure measurements were made for a range of interaction types and incident shock strengths over a transverse cylinder, with emphasis on the 3 and 4 type interaction regions. The measurements were compared with the simple Edney, Keyes, and Hains models for a range of interaction configurations and freestream conditions. The complex flowfields and aerothermal loads generated by multiple-shock impingement, while not generating as large peak loads, provide important test cases for code prediction. The detailed heat transfer and pressure measurements proved a good basis for evaluating the accuracy of simple prediction methods and detailed numerical solutions for laminar and transitional regions or shock/shock interactions.

  17. An integrated assessment of global and regional water demands for electricity generation to 2095

    SciTech Connect

    Davies, Evan; Kyle, G. Page; Edmonds, James A.

    2013-02-01

    Electric power plants currently account for approximately one-half of the global industrial water withdrawal. While continued expansion of the electric sector seems likely into the future, the consequent water demands are quite uncertain, and will depend on highly variable water intensities by electricity technologies, at present and in the future. Using GCAM, an integrated assessment model of energy, agriculture, and climate change, we first establish lower-bound, median, and upper-bound estimates for present-day electric sector water withdrawals and consumption by individual electric generation technologies in each of 14 geopolitical regions, and compare them with available estimates of regional industrial or electric sector water use. We then explore the evolution of global and regional electric sector water use over the next century, focusing on uncertainties related to withdrawal and consumption intensities for a variety of electric generation technologies, rates of change of power plant cooling system types, and rates of adoption of a suite of water-saving technologies. Results reveal that the water withdrawal intensity of electricity generation is likely to decrease in the near term with capital stock turnover, as wet towers replace once-through flow cooling systems and advanced electricity generation technologies replace conventional ones. An increase in consumptive use accompanies the decrease in water withdrawal rates; however, a suite of water conservation technologies currently under development could compensate for this increase in consumption. Finally, at a regional scale, water use characteristics vary significantly based on characteristics of the existing capital stock and the selection of electricity generation technologies into the future.

  18. Seismic activity monitoring in the Izvorul Muntelui dam region

    NASA Astrophysics Data System (ADS)

    Borleanu, Felix; Otilia Placinta, Anca; Popa, Mihaela; Adelin Moldovan, Iren; Popescu, Emilia

    2016-04-01

    Earthquakes occurrences near the artificial water reservoirs are caused by stress variation due to the weight of water, weakness of fractures or faults and increasing of pore pressure in crustal rocks. In the present study we aim to investigate how Izvorul Muntelui dam, located in the Eastern Carpathians influences local seismicity. For this purpose we selected from the seismic bulletins computed within National Data Center of National Institute for Earth Physics, Romania, crustal events occurred between 984 and 2015 in a range of 0.3 deg around the artificial lake. Subsequently to improve the seismic monitoring of the region we applied a cross-correlation detector on the continuous recordings of Bicaz (BIZ) seismic stations. Besides the tectonic events we detected sources within this region that periodically generate artificial evens. We couldn't emphasize the existence of a direct correlation between the water level variations and natural seismicity of the investigated area.

  19. Active region upflows. I. Multi-instrument observations

    NASA Astrophysics Data System (ADS)

    Vanninathan, K.; Madjarska, M. S.; Galsgaard, K.; Huang, Z.; Doyle, J. G.

    2015-12-01

    Context. We study upflows at the edges of active regions, called AR outflows, using multi-instrument observations. Aims: This study intends to provide the first direct observational evidence of whether chromospheric jets play an important role in furnishing mass that could sustain coronal upflows. The evolution of the photospheric magnetic field, associated with the footpoints of the upflow region and the plasma properties of active region upflows is investigated with the aim of providing information for benchmarking data-driven modelling of this solar feature. Methods: We spatially and temporally combine multi-instrument observations obtained with the Extreme-ultraviolet Imaging Spectrometer on board the Hinode, the Atmospheric Imaging Assembly and the Helioseismic Magnetic Imager instruments on board the Solar Dynamics Observatory and the Interferometric BI-dimensional Spectro-polarimeter installed at the National Solar Observatory, Sac Peak, to study the plasma parameters of the upflows and the impact of the chromosphere on active region upflows. Results: Our analysis shows that the studied active region upflow presents similarly to those studied previously, i.e. it displays blueshifted emission of 5-20 kms-1 in Fe xii and Fe xiii and its average electron density is 1.8 × 109 cm-3 at 1 MK. The time variation of the density is obtained showing no significant change (in a 3σ error). The plasma density along a single loop is calculated revealing a drop of 50% over a distance of ~20 000 km along the loop. We find a second velocity component in the blue wing of the Fe xii and Fe xiii lines at 105 kms-1 reported only once before. For the first time we study the time evolution of this component at high cadence and find that it is persistent during the whole observing period of 3.5 h with variations of only ±15 kms-1. We also, for the first time, study the evolution of the photospheric magnetic field at high cadence and find that magnetic flux diffusion is

  20. A Molecular Chipper technology for CRISPR sgRNA library generation and functional mapping of noncoding regions

    PubMed Central

    Cheng, Jijun; Roden, Christine A.; Pan, Wen; Zhu, Shu; Baccei, Anna; Pan, Xinghua; Jiang, Tingting; Kluger, Yuval; Weissman, Sherman M.; Guo, Shangqin; Flavell, Richard A.; Ding, Ye; Lu, Jun

    2016-01-01

    Clustered regularly-interspaced palindromic repeats (CRISPR)-based genetic screens using single-guide-RNA (sgRNA) libraries have proven powerful to identify genetic regulators. Applying CRISPR screens to interrogate functional elements in noncoding regions requires generating sgRNA libraries that are densely covering, and ideally inexpensive, easy to implement and flexible for customization. Here we present a Molecular Chipper technology for generating dense sgRNA libraries for genomic regions of interest, and a proof-of-principle screen that identifies novel cis-regulatory domains for miR-142 biogenesis. The Molecular Chipper approach utilizes a combination of random fragmentation and a type III restriction enzyme to derive a densely covering sgRNA library from input DNA. Applying this approach to 17 microRNAs and their flanking regions and with a reporter for miR-142 activity, we identify both the pre-miR-142 region and two previously unrecognized cis-domains important for miR-142 biogenesis, with the latter regulating miR-142 processing. This strategy will be useful for identifying functional noncoding elements in mammalian genomes. PMID:27025950

  1. Formation of active region and quiescent prominence magnetic field configurations

    NASA Technical Reports Server (NTRS)

    An, C.-H.; Bao, J. J.; Wu, S. T.

    1986-01-01

    To investigate the formation of prominences, researchers studied chromospheric mass injection into an overlying coronal dipole magnetic field using a 2-D ideal magnetohydrodynamic (MHD) numerical model. Researchers propose that active region prominences are formed by chromospheric plasmas injected directly into the overlying coronal magnetic field and that quiescent prominences are formed by plasmas evaporated at the interface between spicules and corona. Hence, for the simulation of an active region prominence magnetic field we inject the mass from one side, but use a symmetric mass injection to form a quiescent prominence field configuration. Researchers try to find optimum conditions for the formation of Kippenhahn-Schuluter(K-S)type field configuration for stable support of the injection plasmas. They find that the formation of K-S type field configuration by mass injection requires a delicate balance between injection velocity, density, and overlying magnetic fields. These results may explain why a prominence does not form on every neutral line.

  2. Tilt Angles of Quiescent Filaments and Filaments of Active Regions

    NASA Astrophysics Data System (ADS)

    Tlatov, A. G.; Kuzanyan, K. M.; Vasil'yeva, V. V.

    2016-04-01

    We carry out study of tilt angles of solar filaments using the data from the two observatories: Meudon Observatory and Kislovodsk Mountain Astronomical Station for the century-long period 1919-2014. We developed special software for digitization of the filaments structures on Hα synoptic maps. The filaments were vectorized in semi-automatic mode. The tilt angles of filaments with respect to the equator (τ) were analyzed. Approximately 2/3 of the filaments have positive angles τ >0, which is defined as when the eastern end of the filaments are closer to the poles than the western ones. We have separated tilts for the filaments which are close to the active region structures and those of quiescent filaments. We found that long quiescent filaments mainly have negative tilts. The filaments which are close to active regions mainly have positive tilt angles.

  3. Fine structure of the magnetic field in active regions

    NASA Astrophysics Data System (ADS)

    Pustilnik, Lev; Beskrovnaya, Nina; Ikhsanov, Nazar

    High-resolution observations with SOHO, SDO, TRACE, HINODE suggest that the solar magnetic field in active regions has a complicated fine structure. There is a large number of thin magnetic arcs extended from the photosphere to corona with almost constant cross-section. We explore a possibility to model the complex of interacting arcs in terms of a dynamical percolating network. A transition of the system into flaring can be triggered by the flute instability of prominences and/or coronal condensations. We speculate around an assumption that the energy release in active regions is governed by the same scenario as dynamical current percolation through a random resistors network in which the saltatory conduction is controlled by a local current level.

  4. Electric currents and coronal heating in NOAA active region 6952

    NASA Technical Reports Server (NTRS)

    Metcalf, T. R.; Canfield, R. C.; Hudson, H. S.; Mickey, D. L.; Wulser, J. -P.; Martens, P. C. H.; Tsuneta, S.

    1994-01-01

    We examine the spatial and temporal relationship between coronal structures observed with the soft X-ray telescope (SXT) on board the Yohkoh spacecraft and the vertical electric current density derived from photospheric vector magnetograms obtained using the Stokes Polarimeter at the Mees Solar Observatory. We focus on a single active region: AR 6952 which we observed on 7 days during 1991 December. For 11 independent maps of the vertical electric current density co-aligned with non-flaring X-ray images, we search for a morphological relationship between sites of high vertical current density in the photosphere and enhanced X-ray emission in the overlying corona. We find no compelling spatial or temporal correlation between the sites of vertical current and the bright X-ray structures in this active region.

  5. Case study of a complex active-region filament eruption

    NASA Astrophysics Data System (ADS)

    Yan, X. L.; Qu, Z. Q.; Kong, D. F.; Deng, L. H.; Xue, Z. K.

    2013-09-01

    Context. We investigated a solar active-region filament eruption associated with a C6.6 class flare and a coronal mass ejection (CME) in NOAA active region 08858 on 2000 February 9. Aims: We aim to better understand the relationship between filament eruptions and the associated flares and CMEs. Methods: Using BBSO, SOHO/EIT, and TRACE observational data, we analyzed the process of the active-region filament eruption in the chromosphere and the corona. Using the SOHO/MDI magnetograms, we investigated the change of the magnetic fields in the photosphere. Using the GOES soft X-ray flux and the SOHO/LASCO images, we identified the flare and CME, which were associated with this active-region filament eruption. Results: The brightenings in the chromosphere are a precursor of the filament expansion. The eruption itself can be divided into four phases: In the initial phase, the intertwined bright and dark strands of the filament expand. Then, the bright strands are divided into three parts with different expansion velocity. Next, the erupting filament-carrying flux rope expands rapidly and combines with the lower part of the expanding bright strands. Finally, the filament erupts accompanied by other dark strands overlying the filament.The overlying magnetic loops and the expansion of the filament strands can change the direction of the eruption. Conclusions: The time delay between the velocity peaks of the filament and that of the two parts of the bright strands clearly demonstrates that the breakup of the bright loops tying on the filament into individual strands is important for its eruption. The eruption is a collection of multiple processes that are physically coupled rather than a single process.

  6. The Antimicrobial Activity of Marinocine, Synthesized by Marinomonas mediterranea, Is Due to Hydrogen Peroxide Generated by Its Lysine Oxidase Activity

    PubMed Central

    Lucas-Elío, Patricia; Gómez, Daniel; Solano, Francisco; Sanchez-Amat, Antonio

    2006-01-01

    Marinocine is a broad-spectrum antibacterial protein synthesized by the melanogenic marine bacterium Marinomonas mediterranea. This work describes the basis for the antibacterial activity of marinocine and the identification of the gene coding for this protein. The antibacterial activity is inhibited under anaerobic conditions and by the presence of catalase under aerobic conditions. Marinocine is active only in culture media containing l-lysine. In the presence of this amino acid, marinocine generates hydrogen peroxide, which causes cell death as confirmed by the increased sensitivity to marinocine of Escherichia coli strains mutated in catalase activity. The gene coding for this novel enzyme was cloned using degenerate PCR with primers designed based on conserved regions in the antimicrobial protein AlpP, synthesized by Pseudoalteromonas tunicata, and some hypothetical proteins. The gene coding for marinocine has been named lodA, standing for lysine oxidase, and it seems to form part of an operon with a second gene, lodB, that codes for a putative dehydrogenase flavoprotein. The identity of marinocine as LodA has been demonstrated by N-terminal sequencing of purified marinocine and generation of lodA mutants that lose their antimicrobial activity. This is the first report on a bacterial lysine oxidase activity and the first time that a gene encoding this activity has been cloned. PMID:16547036

  7. Simulation of Active-Region-Scale Flux Emergence

    NASA Astrophysics Data System (ADS)

    Manchester, W.; van der Holst, B.

    2015-12-01

    Shear flows long observed in solar active regions are now understood to be a consequence of the Lorentz force that develops from a complex interaction between magnetic fields and the thermal pressure of the Sun's gravitationally stratified atmosphere. The shearing motions transport magnetic flux and energy from the submerged portion of the field to the corona providing the necessary energy for flares, filament eruptions and CMEs. To further examine this shearing process, we simulate flux emergence on the scale of active regions with a large-scale model of the near surface convection zone constructed on an adaptive spherical grid. This model is designed to simulate flux emerging on the scale of active regions from a depth of 30 Mm. Here, we show results of a twisted flux rope emerging through the hierarchy of granular convection, and examine the flow patterns that arise as the flux approaches the photosphere. We show how these organized flows driven by the Lorentz force cause the coronal field evolve to a highly non-potential configuration capable of driving solar eruptions such as CMEs and flares.

  8. Analysis of rice Act1 5' region activity in transgenic rice plants.

    PubMed Central

    Zhang, W; McElroy, D; Wu, R

    1991-01-01

    The 5' region of the rice actin 1 gene (Act1) has been developed as an efficient regulator of foreign gene expression in transgenic rice plants. To determine the pattern and level of rice Act1 5' region activity, transgenic rice plants containing the Act1 5' region fused to a bacterial beta-glucuronidase (Gus) coding sequence were generated. Two independent clonal lines of transgenic rice plants were analyzed in detail. Quantitative analysis showed that tissue from these transgenic rice plants have a level of GUS protein that represents as much as 3% of total soluble protein. We were able to demonstrate that Act1-Gus gene expression is constitutive throughout the sporophytic and gametophytic tissues of these transgenic rice plants. Plants from one transgenic line were analyzed for the segregation of GUS activity in pollen by in situ histochemical staining, and the inheritance and stability of Act1-Gus expression were assayed in subsequently derived progeny plants. PMID:1821763

  9. Multiple Generations of Faulting: A Kinematic Analysis of the Lagarfljót Region, Northeast Iceland

    NASA Astrophysics Data System (ADS)

    Runnals, K.; Karson, J. A.; Fiorentino, A. J., II

    2014-12-01

    The North American/Eurasian plate boundary in Iceland is structurally diverse with oblique rifts, volcanic fissure swarms, and transform zones. Lagarfljót is a lake located in the Tertiary flood basalts of East Iceland that range in age from ~7 to 3 Ma. The lake is approximately 50 km E of the actively spreading, NS-trending, Northern Rift Zone (NVZ), and occupies a northeast-trending depression in an area of strong NS lineaments. A flexure zone runs N-S across the southern part of the lake, and predates an angular unconformity in the regional lava pile. Exposures in cliffs along the lakeshore and stream cuts above unveil a series of dikes and faults that can be correlated with the lineaments, and indicate a complicated tectonic history. Fault zones are characterized by fault breccia, cataclasite and gouge with well-developed slickenlines and clear shear-sense indicators. Fault gouge in individual shear zones ranges from centimeters to meters in thickness. Cross cutting relationships define the relative ages of 2 families of structures, with both post-dating the flexure. The older generation of faults are NS-striking, dextral, strike-slip faults. These are cut by NE-striking, normal faults. The normal faults are almost exclusively located along or near the margins of large dikes or swarms of dikes ranging from 1 - 5 m wide. Displacements along individual normal faults range from centimeters up to 8 m. Some faults cut the lavas above the unconformity and locally rotated structures suggest that limited tilting of the lava pile occurred during faulting. These findings may be related to larger scale processes of propagation and relocation of the NVZ.

  10. The impact of H2S emissions on future geothermal power generation - The Geysers region, California

    NASA Technical Reports Server (NTRS)

    Leibowitz, L. P.

    1977-01-01

    The future potential for geothermal power generation in the Geysers region of California is as much as 10 times the current 502 MW(e) capacity. However, environmental factors such as H2S emissions and institutional considerations may play the primary role in determining the rate and ultimate level of development. In this paper a scenario of future geothermal generation capacity and H2S emissions in the Geysers region is presented. Problem areas associated with H2S emissions, H2S abatement processes, plant operations, and government agency resources are described. The impact of H2S emissions on future development and the views of effected organizations are discussed. Potential actions needed to remove these constraints are summarized.

  11. Altered regional activity and inter-regional functional connectivity in psychogenic non-epileptic seizures.

    PubMed

    Li, Rong; Li, Yibo; An, Dongmei; Gong, Qiyong; Zhou, Dong; Chen, Huafu

    2015-01-01

    Although various imaging studies have focused on detecting the cerebral function underlying psychogenic non-epileptic seizures (PNES), the nature of PNES remains poorly understood. In this study, we combined the resting state fMRI with fractional amplitude of low-frequency fluctuations (fALFF) and functional connectivity based on the seed voxel linear correlation approach to examine the alterations of regional and inter-regional network cerebral functions in PNES. A total of 20 healthy controls and 18 patients were enrolled. The PNES patients showed significantly increased fALFF mainly in the dorsolateral prefrontal cortex (DLPFC), parietal cortices, and motor areas, as well as decreased fALFF in the triangular inferior frontal gyrus. Thus, our results add to literature suggesting abnormalities of neural synchrony in PNES. Moreover, PNES exhibited widespread inter-regional neural network deficits, including increased (DLPFC, sensorimotor, and limbic system) and decreased (ventrolateral prefrontal cortex) connectivity, indicating that changes in the regional cerebral function are related to remote inter-regional network deficits. Correlation analysis results revealed that the connectivity between supplementary motor area and anterior cingulate cortex correlated with the PNES frequency, further suggesting the skewed integration of synchronous activity could predispose to the occurrence of PNES. Our findings provided novel evidence to investigate the pathophysiological mechanisms of PNES. PMID:26109123

  12. Interactive coupling of regional atmosphere with biosphere in the new generation regional climate system model REMO-iMOVE

    NASA Astrophysics Data System (ADS)

    Wilhelm, C.; Rechid, D.; Jacob, D.

    2014-06-01

    The main objective of this study is the coupling of the regional climate model REMO with a new land surface scheme including dynamic vegetation phenology, and the evaluation of the new model version called REMO with interactive MOsaic-based VEgetation: REMO-iMOVE. First, we focus on the documentation of the technical aspects of the new model constituents and the coupling mechanism. The representation of vegetation in iMOVE is based on plant functional types (PFTs). Their geographical distribution is prescribed to the model which can be derived from different land surface data sets. Here, the PFT distribution is derived from the GLOBCOVER 2000 data set which is available on 1 km × 1 km horizontal resolution. Plant physiological processes like photosynthesis, respiration and transpiration are incorporated into the model. The vegetation modules are fully coupled to atmosphere and soil. In this way, plant physiological activity is directly driven by atmospheric and soil conditions at the model time step (two minutes to some seconds). In turn, the vegetation processes and properties influence the exchange of substances, energy and momentum between land and atmosphere. With the new coupled regional model system, dynamic feedbacks between vegetation, soil and atmosphere are represented at regional to local scale. In the evaluation part, we compare simulation results of REMO-iMOVE and of the reference version REMO2009 to multiple observation data sets of temperature, precipitation, latent heat flux, leaf area index and net primary production, in order to investigate the sensitivity of the regional model to the new land surface scheme and to evaluate the performance of both model versions. Simulations for the regional model domain Europe on a horizontal resolution of 0.44° had been carried out for the time period 1995-2005, forced with ECMWF ERA-Interim reanalyses data as lateral boundary conditions. REMO-iMOVE is able to simulate the European climate with the same

  13. Generation of Multivariate Surface Weather Series with Use of the Stochastic Weather Generator Linked to Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Dubrovsky, M.; Farda, A.; Huth, R.

    2012-12-01

    The regional-scale simulations of weather-sensitive processes (e.g. hydrology, agriculture and forestry) for the present and/or future climate often require high resolution meteorological inputs in terms of the time series of selected surface weather characteristics (typically temperature, precipitation, solar radiation, humidity, wind) for a set of stations or on a regular grid. As even the latest Global and Regional Climate Models (GCMs and RCMs) do not provide realistic representation of statistical structure of the surface weather, the model outputs must be postprocessed (downscaled) to achieve the desired statistical structure of the weather data before being used as an input to the follow-up simulation models. One of the downscaling approaches, which is employed also here, is based on a weather generator (WG), which is calibrated using the observed weather series and then modified (in case of simulations for the future climate) according to the GCM- or RCM-based climate change scenarios. The present contribution uses the parametric daily weather generator M&Rfi to follow two aims: (1) Validation of the new simulations of the present climate (1961-1990) made by the ALADIN-Climate/CZ (v.2) Regional Climate Model at 25 km resolution. The WG parameters will be derived from the RCM-simulated surface weather series and compared to those derived from observational data in the Czech meteorological stations. The set of WG parameters will include selected statistics of the surface temperature and precipitation (characteristics of the mean, variability, interdiurnal variability and extremes). (2) Testing a potential of RCM output for calibration of the WG for the ungauged locations. The methodology being examined will consist in using the WG, whose parameters are interpolated from the surrounding stations and then corrected based on a RCM-simulated spatial variability. The quality of the weather series produced by the WG calibrated in this way will be assessed in terms

  14. Dependence of hydropower energy generation on forests in the Amazon Basin at local and regional scales

    PubMed Central

    Stickler, Claudia M.; Coe, Michael T.; Costa, Marcos H.; Nepstad, Daniel C.; McGrath, David G.; Dias, Livia C. P.; Rodrigues, Hermann O.; Soares-Filho, Britaldo S.

    2013-01-01

    Tropical rainforest regions have large hydropower generation potential that figures prominently in many nations’ energy growth strategies. Feasibility studies of hydropower plants typically ignore the effect of future deforestation or assume that deforestation will have a positive effect on river discharge and energy generation resulting from declines in evapotranspiration (ET) associated with forest conversion. Forest loss can also reduce river discharge, however, by inhibiting rainfall. We used land use, hydrological, and climate models to examine the local “direct” effects (through changes in ET within the watershed) and the potential regional “indirect” effects (through changes in rainfall) of deforestation on river discharge and energy generation potential for the Belo Monte energy complex, one of the world’s largest hydropower plants that is currently under construction on the Xingu River in the eastern Amazon. In the absence of indirect effects of deforestation, simulated deforestation of 20% and 40% within the Xingu River basin increased discharge by 4–8% and 10–12%, with similar increases in energy generation. When indirect effects were considered, deforestation of the Amazon region inhibited rainfall within the Xingu Basin, counterbalancing declines in ET and decreasing discharge by 6–36%. Under business-as-usual projections of forest loss for 2050 (40%), simulated power generation declined to only 25% of maximum plant output and 60% of the industry’s own projections. Like other energy sources, hydropower plants present large social and environmental costs. Their reliability as energy sources, however, must take into account their dependence on forests. PMID:23671098

  15. Echo-planar magnetic resonance imaging studies of frontal cortex activation during word generation in humans.

    PubMed Central

    McCarthy, G; Blamire, A M; Rothman, D L; Gruetter, R; Shulman, R G

    1993-01-01

    Nine subjects were studied by high-speed magnetic resonance imaging while performing language-based tasks. Subjects were asked either to repeat or to generate verbs associated with nouns read by an experimenter while magnetic resonance images were obtained of the left inferior frontal lobe. The echo-planar imaging sequence was used with a gradient echo time of 70 ms to give an apparent transverse relaxation time weighting (T2* that is sensitive to local hemoglobin levels. Images were acquired every 3 s (repetition time) in series of 32. In plane resolution was 6 x 4.5 mm and slice thickness was 10 mm. An increase in signal accompanied performance of the tasks, with significantly more activation for verb generation than for repeating. The activation effect occurred within 3 s after task onset and could be observed in single images from individual subjects. The primary focus of activation appeared in gray matter along a sulcus anterior to the lateral sulcus that included the anterior insula, Brodmann's area 47, and extending to area 10. Little or no activation of this region was found for a passive listening, covert generation, or mouth-movement control tasks. Significant activation was also found for a homologous region in the right frontal cortex but not for control regions in calcarine cortex. These results are consistent with prior studies that have used positron emission tomography imaging with 15O-labeled water as a blood flow tracer. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8506340

  16. Active region upflows. II. Data driven magnetohydrodynamic modelling

    NASA Astrophysics Data System (ADS)

    Galsgaard, K.; Madjarska, M. S.; Vanninathan, K.; Huang, Z.; Presmann, M.

    2015-12-01

    Context. Observations of many active regions show a slow systematic outflow/upflow from their edges lasting from hours to days. At present no physical explanation has been proven, while several suggestions have been put forward. Aims: This paper investigates one possible method for maintaining these upflows assuming, that convective motions drive the magnetic field to initiate them through magnetic reconnection. Methods: We use Helioseismic and Magnetic Imager (HMI) data to provide an initial potential 3D magnetic field of the active region NOAA 11123 on 2010 November 13 where the characteristic upflow velocities are observed. A simple 1D hydrostatic atmospheric model covering the region from the photosphere to the corona is derived. Local correlation tracking of the magnetic features in the HMI data is used to derive a proxy for the time dependent velocity field. The time dependent evolution of the system is solved using a resistive 3D magnetohydrodynamic code. Results: The magnetic field contains several null points located well above the photosphere, with their fan planes dividing the magnetic field into independent open and closed flux domains. The stressing of the interfaces between the different flux domains is expected to provide locations where magnetic reconnection can take place and drive systematic flows. In this case, the region between the closed and open flux is identified as the region where observations find the systematic upflows. Conclusions: In the present experiment, the driving only initiates magneto-acoustic waves without driving any systematic upflows at any of the flux interfaces. Movie is available in electronic form at http://www.aanda.org

  17. Active control of fan-generated plane wave noise

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.; Nuckolls, William E.; Santamaria, Odillyn L.; Martinson, Scott D.

    1993-01-01

    Subsonic propulsion systems for future aircraft may incorporate ultra-high bypass ratio ducted fan engines whose dominant noise source is the fan with blade passage frequency less than 1000 Hz. This low frequency combines with the requirement of a short nacelle to diminish the effectiveness of passive duct liners. Active noise control is seen as a viable method to augment the conventional passive treatments. An experiment to control ducted fan noise using a time domain active adaptive system is reported. The control sound source consists of loudspeakers arrayed around the fan duct. The error sensor location is in the fan duct. The purpose of this experiment is to demonstrate that the in-duct error sensor reduces the mode spillover in the far field, thereby increasing the efficiency of the control system. In this first series of tests, the fan is configured so that predominantly zero order circumferential waves are generated. The control system is found to reduce the blade passage frequency tone significantly in the acoustic far field when the mode orders of the noise source and of the control source are the same. The noise reduction is not as great when the mode orders are not the same even though the noise source modes are evanescent, but the control system converges stably and global noise reduction is demonstrated in the far field. Further experimentation is planned in which the performance of the system will be evaluated when higher order radial and spinning modes are generated.

  18. Experimental generation of single photons via active multiplexing

    SciTech Connect

    Ma Xiaosong; Zotter, Stefan; Kofler, Johannes; Jennewein, Thomas; Zeilinger, Anton

    2011-04-15

    An on-demand single-photon source is a fundamental building block in quantum science and technology. We experimentally demonstrate the proof of concept for a scheme to generate on-demand single photons via actively multiplexing several heralded photons probabilistically produced from pulsed spontaneous parametric down-conversions (SPDCs). By utilizing a four-photon-pair source, an active feed-forward technique, and an ultrafast single-photon router, we show a fourfold enhancement of the output photon rate. Simultaneously, we maintain the quality of the output single-photon states, confirmed by correlation measurements. We also experimentally verify, via Hong-Ou-Mandel interference, that the router does not affect the indistinguishability of the single photons. Furthermore, we give numerical simulations, which indicate that photons based on multiplexing of four SPDC sources can outperform the heralding based on highly advanced photon-number-resolving detectors. Our results show a route for on-demand single-photon generation and the practical realization of scalable linear optical quantum-information processing.

  19. Dynamic coupling of regional atmosphere to biosphere in the new generation regional climate system model REMO-iMOVE

    NASA Astrophysics Data System (ADS)

    Wilhelm, C.; Rechid, D.; Jacob, D.

    2013-05-01

    The main objective of this study is the coupling of the regional climate model REMO to a 3rd generation land surface scheme and the evaluation of the new model version of REMO, called REMO with interactive MOsaic-based VEgetation: REMO-iMOVE. Attention is paid to the documentation of the technical aspects of the new model constituents and the coupling mechanism. We compare simulation results of REMO-iMOVE and of the reference version REMO2009, to investigate the sensitivity of the regional model to the new land surface scheme. An 11 yr climate model run (1995-2005), forced with ECMWF ERA-Interim lateral boundary conditions, over Europe in 0.44° resolution of both model versions was carried out, to represent present day European climate. The result of these experiments are compared to multiple temperature, precipitation, heat flux and leaf area index observation data, to determine the differences in the model versions. The new model version has further the ability to model net primary productivity for the given plant functional types. This new feature is thoroughly evaluated by literature values of net primary productivity of different plant species in European climatic regions. The new model version REMO-iMOVE is able to model the European climate in the same quality as the parent model version REMO2009 does. The differences in the results of the two model versions stem from the differences in the dynamics of vegetation cover and density and can be distinct in some regions, due to the influences of these parameters to the surface heat and moisture fluxes. The modeled inter-annual variability in the phenology as well as the net primary productivity lays in the range of observations and literature values for most European regions. This study also reveals the need for a more sophisticated soil moisture representation in the newly developed model version REMO-iMOVE to be able to treat the differences in plant functional types. This gets especially important if the

  20. Coaxial Mono-Energetic Gamma Generator for Active Interrogation

    NASA Astrophysics Data System (ADS)

    Ludewigt, B. A.; Antolak, A. J.; Henestroza, E.; Kwan, J. W.; Leitner, M.; Leung, K.-N.; Waldron, W.; Wilde, S.

    2009-03-01

    Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the 11B(p,γ)12C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the 11B(p,γ)12C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rf-antenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB6 tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 μs long pulses, and a 1% duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.

  1. Coaxial Mono-Energetic Gamma Generator for Active Interrogation

    SciTech Connect

    Ludewigt, Bernhard A.; Antolak, A.J.; Henestroza, E.; Leitner, M.; Leung, K.-N.; Waldron, W.; Wilde, S.; Kwan, J.W.

    2008-08-01

    Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the 11B(p,gamma)12C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the 11B(p,gamma)12C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rf-antenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB6 tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 mu s long pulses, and a 1percent duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.

  2. Coaxial Mono-Energetic Gamma Generator for Active Interrogation

    SciTech Connect

    Ludewigt, B. A.; Henestroza, E.; Kwan, J. W.; Leitner, M.; Leung, K.-N.; Waldron, W.; Wilde, S.; Antolak, A. J.

    2009-03-10

    Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the {sup 11}B(p,{gamma}){sup 12}C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the {sup 11}B(p,{gamma}){sup 12}C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rf-antenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB{sub 6} tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 {mu}s long pulses, and a 1% duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.

  3. Microglial cell activation is a source of metalloproteinase generation during hemorrhagic transformation

    PubMed Central

    del Zoppo, Gregory J; Frankowski, Harald; Gu, Yu-Huan; Osada, Takashi; Kanazawa, Masato; Milner, Richard; Wang, Xiaoyun; Hosomi, Naohisa; Mabuchi, Takuma; Koziol, James A

    2012-01-01

    Hemorrhage and edema accompany evolving brain tissue injury after ischemic stroke. In patients, these events have been associated with metalloproteinase (MMP)-9 in plasma. Both the causes and cellular sources of MMP-9 generation in this setting have not been defined. MMP-2 and MMP-9 in nonhuman primate tissue in regions of plasma leakage, and primary murine microglia and astrocytes, were assayed by immunocytochemistry, zymography, and real-time RT-PCR. Ischemia-related hemorrhage was associated with microglial activation in vivo, and with the leakage of plasma fibronectin and vitronectin into the surrounding tissue. In strict serum-depleted primary cultures, by zymography, pro-MMP-9 was generated by primary murine microglia when exposed to vitronectin and fibronectin. Protease secretion was enhanced by experimental ischemia (oxygen-glucose deprivation, OGD). Primary astrocytes, on each matrix, generated only pro-MMP-2, which decreased during OGD. Microglia–astrocyte contact enhanced pro-MMP-9 generation in a cell density-dependent manner under normoxia and OGD. Compatible with observations in a high quality model of focal cerebral ischemia, microglia, but not astrocytes, respond to vitronectin and fibronectin, found when plasma extravasates into the injured region. Astrocytes alone do not generate pro-MMP-9. These events explain the appearance of MMP-9 antigen in association with ischemia-induced cerebral hemorrhage and edema. PMID:22354151

  4. Forecasting municipal solid waste generation in a fast-growing urban region with system dynamics modeling.

    PubMed

    Dyson, Brian; Chang, Ni-Bin

    2005-01-01

    Both planning and design of municipal solid waste management systems require accurate prediction of solid waste generation. Yet achieving the anticipated prediction accuracy with regard to the generation trends facing many fast-growing regions is quite challenging. The lack of complete historical records of solid waste quantity and quality due to insufficient budget and unavailable management capacity has resulted in a situation that makes the long-term system planning and/or short-term expansion programs intangible. To effectively handle these problems based on limited data samples, a new analytical approach capable of addressing socioeconomic and environmental situations must be developed and applied for fulfilling the prediction analysis of solid waste generation with reasonable accuracy. This study presents a new approach--system dynamics modeling--for the prediction of solid waste generation in a fast-growing urban area based on a set of limited samples. To address the impact on sustainable development city wide, the practical implementation was assessed by a case study in the city of San Antonio, Texas (USA). This area is becoming one of the fastest-growing regions in North America due to the economic impact of the North American Free Trade Agreement (NAFTA). The analysis presents various trends of solid waste generation associated with five different solid waste generation models using a system dynamics simulation tool--Stella. Research findings clearly indicate that such a new forecasting approach may cover a variety of possible causative models and track inevitable uncertainties down when traditional statistical least-squares regression methods are unable to handle such issues. PMID:16009300

  5. Non-dipole effects on high-order harmonic generation towards the long wavelength region

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaosong; Wang, Zhe

    2016-04-01

    The non-dipole (ND) effects on high-order harmonic generation (HHG) with the laser wavelength increasing towards the long wavelength region are investigated. Two major phenomena due to the ND effects, the decrease of the HHG intensity and the shift of the harmonic spectrum, are discussed. It is shown that, for the commonly used laser intensity I∼1014 W/cm2 and target with ionization potential Ip ∼ 0.5 a . u ., the ND effects become nonnegligible when the laser wavelength is increased to the mid-infrared region of several thousand nanometers. It is also found that the variation of the ND effects presents different rules compared with those towards the high intensity region. Two fitting formulas are proposed to describe the variation rules. The physical meanings of the fitting results are discussed with classical calculation.

  6. Holocene fire activity in the Carpathian region: regional climate vs. local controls

    NASA Astrophysics Data System (ADS)

    Florescu, Gabriela; Feurdean, Angelica

    2015-04-01

    Introduction. Fire drives significant changes in ecosystem structure and function, diversity, species evolution, biomass dynamics and atmospheric composition. Palaeodata and model-based studies have pointed towards a strong connection between fire activity, climate, vegetation and people. Nevertheless, the relative importance of these factors appears to be strongly variable and a better understanding of these factors and their interaction needs a thorough investigation over multiple spatial (local to global) and temporal (years to millennia) scales. In this respect, sedimentary charcoal, associated with other proxies of climate, vegetation and human impact, represents a powerful tool of investigating changes in past fire activity, especially in regions with scarce fire dataset such as the CE Europe. Aim. To increase the spatial and temporal coverage of charcoal records and facilitate a more critical examination of the patterns, drivers and consequences of biomass burning over multiple spatial and temporal scales in CE Europe, we have investigated 6 fossil sequences in the Carpathian region (northern Romania). These are located in different geographical settings, in terms of elevation, vegetation composition, topography and land-use. Specific questions are: i) determine trends in timing and magnitude of fire activity, as well as similarities and differences between elevations; ii) disentangle the importance of regional from local controls in fire activity; iii) evaluate ecological consequences of fire on landscape composition, structure and diversity. Methods. We first determine the recent trends in fire activity (the last 150 years) from charcoal data and compare them with instrumental records of temperature, precipitation, site history and topography for a better understanding of the relationship between sedimentary charcoal and historical fire activity. We then statistically quantify centennial to millennial trends in fire activity (frequency, magnitude) based on

  7. Monitoring rice farming activities in the Mekong Delta region

    NASA Astrophysics Data System (ADS)

    Nguyen, S. T.; Chen, C. F.; Chen, C. R.; Chiang, S. H.; Chang, L. Y.; Khin, L. V.

    2015-12-01

    Half of the world's population depends on rice for survival. Rice agriculture thus plays an important role in the developing world's economy. Vietnam is one of the largest rice producers and suppliers on earth and more than 80% of the exported rice was produced from the Mekong Delta region, which is situated in the southwestern Vietnam and encompasses approximately 40,000 km2. Changes in climate conditions could likely trigger the increase of insect populations and rice diseases, causing the potential loss of rice yields. Monitoring rice-farming activities through crop phenology detection can provide policymakers with timely strategies to mitigate possible impacts on the potential yield as well as rice grain exports to ensure food security for the region. The main objective of this study is to develop a logistic-based algorithm to investigate rice sowing and harvesting activities from the multi-temporal Moderate Resolution Imaging Spectroradiometer (MODIS)-Landsat fusion data. We processed the data for two main cropping seasons (i.e., winter-spring and summer-autumn seasons) through a three-step procedure: (1) MODIS-Landsat data fusion, (2) construction of the time-series enhanced vegetation index 2 (EVI2) data, (3) rice crop phenology detection. The EVI2 data derived from the fusion results between MODIS and Landsat data were compared with that of Landsat data indicated close correlation between the two datasets (R2 = 0.93). The time-series EVI2 data were processed using the double logistic method to detect the progress of sowing and harvesting activities in the region. The comparisons between the estimated sowing and harvesting dates and the field survey data revealed the root mean squared error (RMSE) values of 8.4 and 5.5 days for the winter-spring crop and 9.4 and 12.8 days for the summer-autumn crop, respectively. This study demonstrates the effectiveness of the double logistic-based algorithm for rice crop monitoring from temporal MODIS-Landsat fusion data

  8. FORMATION OF CORONAL HOLES ON THE ASHES OF ACTIVE REGIONS

    SciTech Connect

    Karachik, Nina V.; Pevtsov, Alexei A.; Abramenko, Valentyna I. E-mail: apevtsov@nso.ed

    2010-05-10

    We investigate the formation of isolated non-polar coronal holes (CHs) on the remnants of decaying active regions (ARs) at the minimum/early ascending phase of sunspot activity. We follow the evolution of four bipolar ARs and measure several parameters of their magnetic fields including total flux, imbalance, and compactness. As regions decay, their leading and following polarities exhibit different dissipation rates: loose polarity tends to dissipate faster than compact polarity. As a consequence, we see a gradual increase in flux imbalance inside a dissipating bipolar region, and later a formation of a CH in place of more compact magnetic flux. Out of four cases studied in detail, two CHs had formed at the following polarity of the decaying bipolar AR, and two CHs had developed in place of the leading polarity field. All four CHs contain a significant fraction of magnetic field of their corresponding AR. Using potential field extrapolation, we show that the magnetic field lines of these CHs were closed on the polar CH at the North, which at the time of the events was in imbalance with the polar CH at the South. This topology suggests that the observed phenomenon may play an important role in transformation of toroidal magnetic field to poloidal field, which is a key step in transitioning from an old solar cycle to a new one. The timing of this observed transition may indicate the end of solar cycle 23 and the beginning of cycle 24.

  9. Helioseismology of pre-emerging active regions. III. Statistical analysis

    SciTech Connect

    Barnes, G.; Leka, K. D.; Braun, D. C.; Birch, A. C.

    2014-05-01

    The subsurface properties of active regions (ARs) prior to their appearance at the solar surface may shed light on the process of AR formation. Helioseismic holography has been applied to samples taken from two populations of regions on the Sun (pre-emergence and without emergence), each sample having over 100 members, that were selected to minimize systematic bias, as described in Paper I. Paper II showed that there are statistically significant signatures in the average helioseismic properties that precede the formation of an AR. This paper describes a more detailed analysis of the samples of pre-emergence regions and regions without emergence based on discriminant analysis. The property that is best able to distinguish the populations is found to be the surface magnetic field, even a day before the emergence time. However, after accounting for the correlations between the surface field and the quantities derived from helioseismology, there is still evidence of a helioseismic precursor to AR emergence that is present for at least a day prior to emergence, although the analysis presented cannot definitively determine the subsurface properties prior to emergence due to the small sample sizes.

  10. GEOPHYSICS, ASTRONOMY AND ASTROPHYSICS: Generation of an isolated sub-100 attosecond pulse in the water-window spectral region

    NASA Astrophysics Data System (ADS)

    Zou, Pu; Li, Ru-Xin; Zeng, Zhi-Nan; Xiong, Hui; Liu, Peng; Leng, Yu-Xin; Fan, Pin-Zhong; Xu, Zhi-Zhan

    2010-01-01

    We propose a scheme to generate isolated attosecond pulses in the water-window spectral region. Based on the numerical solutions of the single active electron model, we investigate high-order harmonic generation in helium atoms driven by a multi-cycle two-colour optical field synthesized by an intense 2000 nm, 20 fs pulse and its frequency-doubled pulse. When the latter is slightly detuned and properly phase shifted with respect to the fundamental laser pulse, an ultra-broad extreme ultraviolet supercontinuum with a spectral width of 130 eV can be generated in the 270-400 eV spectral regions. A supercontinuum from 280-340 eV in the water window can be selected to yield an isolated 67 attosecond pulse without employing any phase compensation. This water window coherent x-ray pulse with less than 100 attosecond duration is a potential tool for studying the ultrafast electronic dynamics of biological samples in water.

  11. Multi-wavelength Observations of Solar Active Region NOAA 7154

    NASA Technical Reports Server (NTRS)

    Bruner, M. E.; Nitta, N. V.; Frank. Z. A.; Dame, L.; Suematsu, Y.

    2000-01-01

    We report on observations of a solar active region in May 1992 by the Solar Plasma Diagnostic Experiment (SPDE) in coordination with the Yohkoh satellite (producing soft X-ray images) and ground-based observatories (producing photospheric magnetograms and various filtergrams including those at the CN 3883 A line). The main focus is a study of the physical conditions of hot (T is approximately greater than 3 MK) coronal loops at their foot-points. The coronal part of the loops is fuzzy but what appear to be their footpoints in the transition region down to the photosphere are compact. Despite the morphological similarities, the footpoint emission at 10(exp 5) K is not quantitatively correlated with that at approximately 300 km above the tau (sub 5000) = 1 level, suggesting that the heat transport and therefore magnetic field topology in the intermediate layer is complicated. High resolution imaging observations with continuous temperature coverage are crucially needed.

  12. Mapping of Fugitive Dust Generation, Transport, and Deposition in the Nogales, Arizona Region Using Enhanced Thematic Mapper Plus (ETM+) Data

    NASA Astrophysics Data System (ADS)

    Stefanov, W. L.; Stefanov, W. L.; Ramsey, M. S.; Christensen, P. R.

    2001-05-01

    Urban centers located along the U.S.-Mexico border represent significant sources of fugitive (airborne) dust. This dust, which can lead to adverse health effects, arises from several factors including construction activities related to land use conversion (i.e., agricultural to residential), unpaved roadways, agricultural activities, and human disturbance of the soil. Fundamental baseline data needed for modeling and monitoring of particulate generation and transport are accurate regional classification of land cover, degree of disturbance, and a metric of land cover change. Identification and delineation of fugitive dust source regions using a purely field-based approach is time and labor intensive and can lead to errors over time as land use changes. Further, restrictions on access to specific areas (such as private lands and reservations) may impede or prevent site investigations in these areas. Remotely gathered information can be used to circumvent these difficulties and provide rapid dust source region identification with quantitative area measurements required in transport models. Landsat ETM+ data was used to identify and delineate surficial materials that were either potential fugitive dust source regions or were important factors in dust transport and deposition. Using a knowledge-based system, land cover was classified into three generalized types: natural and disturbed soils (dust generation sites); asphalt, concrete, and urban materials (dust transport areas); and vegetated areas (dust deposition sites). Accuracy of the land cover classification was assessed using field verification, comparison of field and image reflectance spectra, and digital aerial orthophotographs. Results of image classification and field verification for Landsat data acquired during the winter of 2000 show a strong correlation, and will be used with data collected during the summer dry season for change detection analysis. The digital format of the classified data is optimal for

  13. High Spatial Resolution Fe XII Observations of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Testa, Paola; De Pontieu, Bart; Hansteen, Viggo

    2016-08-01

    We use UV spectral observations of active regions with the Interface Region Imaging Spectrograph (IRIS) to investigate the properties of the coronal Fe xii 1349.4 Å emission at unprecedented high spatial resolution (∼0.33″). We find that by using appropriate observational strategies (i.e., long exposures, lossless compression), Fe xii emission can be studied with IRIS at high spatial and spectral resolution, at least for high-density plasma (e.g., post-flare loops and active region moss). We find that upper transition region (TR; moss) Fe xii emission shows very small average Doppler redshifts ({v}{{D}} ∼ 3 km s‑1) as well as modest non-thermal velocities (with an average of ∼24 km s‑1 and the peak of the distribution at ∼15 km s‑1). The observed distribution of Doppler shifts appears to be compatible with advanced three-dimensional radiative MHD simulations in which impulsive heating is concentrated at the TR footpoints of a hot corona. While the non-thermal broadening of Fe xii 1349.4 Å peaks at similar values as lower resolution simultaneous Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) measurements of Fe xii 195 Å, IRIS observations show a previously undetected tail of increased non-thermal broadening that might be suggestive of the presence of subarcsecond heating events. We find that IRIS and EIS non-thermal line broadening measurements are affected by instrumental effects that can only be removed through careful analysis. Our results also reveal an unexplained discrepancy between observed 195.1/1349.4 Å Fe xii intensity ratios and those predicted by the CHIANTI atomic database.

  14. Ancient Tectonic and Volcanic Activity in the Tharsis Region

    NASA Astrophysics Data System (ADS)

    Werner, S. C.; Kronberg, P.; Hauber, E.; Grott, M.; Steinberger, B.; Torsvik, T. H.; Neukum, G.

    The two topographically dominating volcanic provinces on Mars are the Tharsis and the Elysium regions, situated close to the equator on the dichotomy boundary between the heavily cratered (older) highlands and the northern lowlands (about 100 degrees apart). The regions are characterized by volcanoes whose morphologies are analogous to volcanic landforms on Earth, and the huge volcanoes in the Tharsis region (Olympus Mons and Tharsis Montes) are prime examples resembling many characteristics of Hawaiian shield volcanoes. The main difference between the Martian and terrestrial volcanoes are their size and the length of the flows, possibly due to higher eruption rates, the "stationary" character of the source (no plate tectonics) and the lower gravity. The Tharsis plateau is the topographically most prominent region on Mars, and associated with an areoid high. On Earth, large geoid highs are related to longlived heterogeneities near the core-mantle boundary that are sources for large igneous provinces. The Tharsis' volcanic vent structures were active at least episodically over the past 4 billion years (based on crater count statistics), which indicates long-lived volcanic and magmatic activity. Two major groups of tectonic features are related to the Tharsis bulge: a concentric set of wrinkle ridges indicating compression radial to Tharsis,and several sets of extensional structures that radiate outward from different centers within Tharsis, indicating tension circumferential to Tharsis. No landforms imply ancient plate tectonics. Here, we present surface ages associated with volcanic and tectonic landforms with a special focus on the ancient magma-tectonic environment (see Grott et al. 2006, this volume). We will examine the long-lived volcanism and tectonic surface expressions and discuss whether Mars volcanism could represent deep mantle plumes.

  15. High Spatial Resolution Fe XII Observations of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Testa, Paola; De Pontieu, Bart; Hansteen, Viggo

    2016-08-01

    We use UV spectral observations of active regions with the Interface Region Imaging Spectrograph (IRIS) to investigate the properties of the coronal Fe xii 1349.4 Å emission at unprecedented high spatial resolution (˜0.33″). We find that by using appropriate observational strategies (i.e., long exposures, lossless compression), Fe xii emission can be studied with IRIS at high spatial and spectral resolution, at least for high-density plasma (e.g., post-flare loops and active region moss). We find that upper transition region (TR; moss) Fe xii emission shows very small average Doppler redshifts ({v}{{D}} ˜ 3 km s‑1) as well as modest non-thermal velocities (with an average of ˜24 km s‑1 and the peak of the distribution at ˜15 km s‑1). The observed distribution of Doppler shifts appears to be compatible with advanced three-dimensional radiative MHD simulations in which impulsive heating is concentrated at the TR footpoints of a hot corona. While the non-thermal broadening of Fe xii 1349.4 Å peaks at similar values as lower resolution simultaneous Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) measurements of Fe xii 195 Å, IRIS observations show a previously undetected tail of increased non-thermal broadening that might be suggestive of the presence of subarcsecond heating events. We find that IRIS and EIS non-thermal line broadening measurements are affected by instrumental effects that can only be removed through careful analysis. Our results also reveal an unexplained discrepancy between observed 195.1/1349.4 Å Fe xii intensity ratios and those predicted by the CHIANTI atomic database.

  16. Chromospheric Evolution and the Flare Activity of Super-Active Region NOAA 6555

    NASA Technical Reports Server (NTRS)

    PrasadC, Debi; Ambastha, Ashok; Srivastava, Nandita; Tripathy, Sushanta C.; Hagyard, Mona J.

    1997-01-01

    Super-active region NOAA 6555 was highly flare productive during the period March 21st - 27th, 1991 of its disk passage. We have studied its chromospheric activity using high spatial resolution H alpha filtergrams taken at Udaipur along with MSFC vector magnetograms. A possible relationship of flare productivity and the variation in shear has been explored. Flares were generally seen in those subareas of the active region which possessed closed magnetic field configuration, whereas only minor flares and/or surges occurred in subareas showing open magnetic field configuration. Physical mechanisms responsible for the observed surges are also discussed.

  17. Implications of Special Regions to Conducting Human Activities on Mars

    NASA Astrophysics Data System (ADS)

    Rummel, J. D.; Barlow, N. G.; Beaty, D. W.; Jones, M. A.; Hipkin, V.

    2014-12-01

    A MEPAG Science Analysis Group (SAG) has undertaken an analysis of Special Regions (SR) on Mars—regions where indigenous martian life could exist or where Earth microbes, if introduced, could survive and reproduce. The SR-SAG has considered the impact of SR on future human activities on the martian surface. Human exploration requires access to in-situ resources, some of which may be found in SR. Water and oxygen for ISRU are found in the atmosphere, surface/near-surface ice, hydrated minerals, and perchlorates. Water ice is most abundant at latitudes poleward of ~60 degrees, but polar darkness, cold temperatures, and CO2 degassing present hazards to human operations in these regions. Accessible water is more limited toward the equator, though temperature and solar energy conditions become more favorable. The possible presence of liquid water in Recurring Slope Lineae and active gullies leads to their treatment as SR. Fuel for surface operations and propellants for crew ascent could be manufactured from the martian atmosphere and surface materials, but dust in the atmosphere may clog ISRU equipment and perchlorate is toxic to humans. Power may be produced from solar or nuclear energy. Reliance on solar energy limits operations to the equatorial zone where easily accessible ice resources are limited. Nuclear power allows surface operations at a range of latitudes, but waste heat could convert some non-SR into SR. Radiation shielding is necessary for long-term human operations on Mars and could be obtained by deposition of regolith or by water storage in tanks or as ice around habitats, or the use of underground habitats. SR-SAG recognizes that it will be impossible for all human-associated processes and operations to be conducted within entirely closed systems. Protocols need to be established so (1) human missions to Mars will not contaminate SR nor be contaminated by materials from them, and (2) human activities on Mars will avoid converting areas into SR.

  18. THE EXPANSION OF ACTIVE REGIONS INTO THE EXTENDED SOLAR CORONA

    SciTech Connect

    Morgan, Huw; Jeska, Lauren; Leonard, Drew

    2013-06-01

    Advanced image processing of Large Angle and Spectrometric Coronagraph Experiment (LASCO) C2 observations reveals the expansion of the active region closed field into the extended corona. The nested closed-loop systems are large, with an apparent latitudinal extent of 50 Degree-Sign , and expanding to heights of at least 12 R{sub Sun }. The expansion speeds are {approx}10 km s{sup -1} in the AIA/SDO field of view, below {approx}20 km s{sup -1} at 2.3 R{sub Sun }, and accelerate linearly to {approx}60 km s{sup -1} at 5 R{sub Sun }. They appear with a frequency of one every {approx}3 hr over a time period of around three days. They are not coronal mass ejections (CMEs) since their gradual expansion is continuous and steady. They are also faint, with an upper limit of 3% of the brightness of background streamers. Extreme ultraviolet images reveal continuous birth and expansion of hot, bright loops from a new active region at the base of the system. The LASCO images show that the loops span a radial fan-like system of streamers, suggesting that they are not propagating within the main coronal streamer structure. The expanding loops brighten at low heights a few hours prior to a CME eruption, and the expansion process is temporarily halted as the closed field system is swept away. Closed magnetic structures from some active regions are not isolated from the extended corona and solar wind, but can expand to large heights in the form of quiescent expanding loops.

  19. Probabilistic analysis of activation volumes generated during deep brain stimulation.

    PubMed

    Butson, Christopher R; Cooper, Scott E; Henderson, Jaimie M; Wolgamuth, Barbara; McIntyre, Cameron C

    2011-02-01

    Deep brain stimulation (DBS) is an established therapy for the treatment of Parkinson's disease (PD) and shows great promise for the treatment of several other disorders. However, while the clinical analysis of DBS has received great attention, a relative paucity of quantitative techniques exists to define the optimal surgical target and most effective stimulation protocol for a given disorder. In this study we describe a methodology that represents an evolutionary addition to the concept of a probabilistic brain atlas, which we call a probabilistic stimulation atlas (PSA). We outline steps to combine quantitative clinical outcome measures with advanced computational models of DBS to identify regions where stimulation-induced activation could provide the best therapeutic improvement on a per-symptom basis. While this methodology is relevant to any form of DBS, we present example results from subthalamic nucleus (STN) DBS for PD. We constructed patient-specific computer models of the volume of tissue activated (VTA) for 163 different stimulation parameter settings which were tested in six patients. We then assigned clinical outcome scores to each VTA and compiled all of the VTAs into a PSA to identify stimulation-induced activation targets that maximized therapeutic response with minimal side effects. The results suggest that selection of both electrode placement and clinical stimulation parameter settings could be tailored to the patient's primary symptoms using patient-specific models and PSAs. PMID:20974269

  20. Emission Measure Distribution and Heating of Two Active Region Cores

    NASA Technical Reports Server (NTRS)

    Tripathi, Durgesh; Klimchuk, James A.; Mason, Helen E.

    2011-01-01

    Using data from the Extreme-ultraviolet Imaging Spectrometer aboard Hinode, we have studied the coronal plasma in the core of two active regions. Concentrating on the area between opposite polarity moss, we found emission measure distributions having an approximate power-law form EM/T(exp 2.4) from log T = 5.55 up to a peak at log T = 6.57. The observations are explained extremely well by a simple nanoflare model. However, in the absence of additional constraints, the observations could possibly also be explained by steady heating.

  1. SOI/MDI studies of active region seismology and evolution

    NASA Technical Reports Server (NTRS)

    Tarbell, Ted D.; Title, Alan; Hoeksema, J. Todd; Scherrer, Phil; Zweibel, Ellen

    1995-01-01

    The solar oscillations investigation (SOI) will study solar active regions using both helioseismic and conventional observation techniques. The Michelson Doppler imager (MDI) can perform Doppler continuum and line depth imagery and can produce longitudinal magnetograms, showing either the full disk or a high resolution field of view. A dynamics program of continuous full disk Doppler observations for two months per year, campaign programs of eight hours of continuous observation per day, and a synoptic magnetic program of about 15 full disk magnetograms per day, are planned. The scientific plans, measurements and observation programs, are described.

  2. C IV Doppler shifts observed in active region filaments

    NASA Technical Reports Server (NTRS)

    Klimchuk, J. A.

    1986-01-01

    The Doppler shift properties of 21 active region filaments were studied using C IV Dopplergram data. Most are associated with corridors of weak magnetic field that separate opposite polarity strong fields seen in photospheric magnetograms. A majority of the filaments are relatively blue shifted, although several lie very close to the dividing lines between blue and red shift. Only one filament in the samples is clearly red shifted. A new calibration procedure for Dopplergrams indicates that sizable zero point offsets are often required. The center-to-limb behavior of the resulting absolute Doppler shifts suggests that filament flows are usually quite small. It is possible that they vanish.

  3. Hinode Observations of an Eruption from a Sigmoidal Active Region

    NASA Astrophysics Data System (ADS)

    Green, L. M.; Wallace, A. J.; Kliem, B.

    2012-08-01

    We analyse the evolution of a bipolar active region which produces an eruption during its decay phase. The soft X-ray arcade develops high shear over a time span of two days and transitions to sigmoidal shortly before the eruption. We propose that the continuous sigmoidal soft X-ray threads indicate that a flux rope has formed which is lying low in the solar atmosphere with a bald patch separatrix surface topology. The formation of the flux rope is driven by the photospheric evolution which is dominated by fragmentation of the main polarities, motion due to supergranular flows and cancellation at the polarity inversion line.

  4. Substrate-emitting semiconductor laser with a trapezoidal active region

    SciTech Connect

    Dikareva, N V; Nekorkin, S M; Karzanova, M V; Zvonkov, B N; Aleshkin, V Ya; Dubinov, A A; Afonenko, A A

    2014-04-28

    Semiconductor lasers with a narrow (∼2°) directional pattern in the planes both parallel and perpendicular to the p–n junction are fabricated. To achieve a low radiation divergence in the p–n junction plane, the active region in this plane was designed in the form of a trapezium. The narrow directional pattern in the plane perpendicular to the p–n junction was ensured by the use of a leaky mode, through which more than 90% of laser power was coupled out. (lasers)

  5. Microfluidic Platform Generates Oxygen Landscapes for Localized Hypoxic Activation

    PubMed Central

    Rexius, Megan L.; Mauleon, Gerardo; Malik, Asrar B.; Rehman, Jalees; Eddington, David T.

    2014-01-01

    An open-well microfluidic platform generates an oxygen landscape using gas-perfused networks which diffuse across a membrane. The device enables real-time analysis of cellular and tissue responses to oxygen tension to define how cells adapt to heterogeneous oxygen conditions found in the physiological setting. We demonstrate that localized hypoxic activation of cells elicited specific metabolic and gene responses in human microvascular endothelial cells and bone marrow-derived mesenchymal stem cells. A robust demonstration of the compatibility of the device with standard laboratory techniques demonstrates the wide utility of the method. This platform is ideally suited to study real-time cell responses and cell-cell interactions within physiologically relevant oxygen landscapes. PMID:25315003

  6. ActivitySim: large-scale agent based activity generation for infrastructure simulation

    SciTech Connect

    Gali, Emmanuel; Eidenbenz, Stephan; Mniszewski, Sue; Cuellar, Leticia; Teuscher, Christof

    2008-01-01

    The United States' Department of Homeland Security aims to model, simulate, and analyze critical infrastructure and their interdependencies across multiple sectors such as electric power, telecommunications, water distribution, transportation, etc. We introduce ActivitySim, an activity simulator for a population of millions of individual agents each characterized by a set of demographic attributes that is based on US census data. ActivitySim generates daily schedules for each agent that consists of a sequence of activities, such as sleeping, shopping, working etc., each being scheduled at a geographic location, such as businesses or private residences that is appropriate for the activity type and for the personal situation of the agent. ActivitySim has been developed as part of a larger effort to understand the interdependencies among national infrastructure networks and their demand profiles that emerge from the different activities of individuals in baseline scenarios as well as emergency scenarios, such as hurricane evacuations. We present the scalable software engineering principles underlying ActivitySim, the socia-technical modeling paradigms that drive the activity generation, and proof-of-principle results for a scenario in the Twin Cities, MN area of 2.6 M agents.

  7. Peptides of the constant region of antibodies display fungicidal activity.

    PubMed

    Polonelli, Luciano; Ciociola, Tecla; Magliani, Walter; Zanello, Pier Paolo; D'Adda, Tiziana; Galati, Serena; De Bernardis, Flavia; Arancia, Silvia; Gabrielli, Elena; Pericolini, Eva; Vecchiarelli, Anna; Arruda, Denise C; Pinto, Marcia R; Travassos, Luiz R; Pertinhez, Thelma A; Spisni, Alberto; Conti, Stefania

    2012-01-01

    Synthetic peptides with sequences identical to fragments of the constant region of different classes (IgG, IgM, IgA) of antibodies (Fc-peptides) exerted a fungicidal activity in vitro against pathogenic yeasts, such as Candida albicans, Candida glabrata, Cryptococcus neoformans, and Malassezia furfur, including caspofungin and triazole resistant strains. Alanine-substituted derivatives of fungicidal Fc-peptides, tested to evaluate the critical role of each residue, displayed unaltered, increased or decreased candidacidal activity in vitro. An Fc-peptide, included in all human IgGs, displayed a therapeutic effect against experimental mucosal and systemic candidiasis in mouse models. It is intriguing to hypothesize that some Fc-peptides may influence the antifungal immune response and constitute the basis for devising new antifungal agents. PMID:22470523

  8. Regional jointing and hydrocarbon generation in Big Sandy gas field, Kentucky

    SciTech Connect

    Loar, S.J.

    1986-05-01

    Producing wells in the Big Sandy gas field depend on well-developed subsurface joint systems to enhance migration into the borehole. To examine the joint systems, the surface joints were studied. Statistical analysis revealed eight regional joint sets: N30/sup 0/W, N10/sup 0/W, N20/sup 0/E, N30/sup 0/E, N40/sup 0/E, N60/sup 0/E, N80/sup 0/E, and east-west. These sets have the same orientations as reservoir joints observed in oriented cores, indicating that they are part of the same systems. Field observations suggest that the regional joint sets formed in at least three phases, which can be classified as hydraulic, tectonic, and unloading. The timing of hydrocarbons was calculated from a subsidence curve for Devonian and younger formations, which was constructed on the basis of published isopach, conodont alteration index, and well data. Plotting the maturation of the Ohio Shale with the regional jointing phases shows that the hydraulic joint sets formed before hydrocarbon generation began, and that the tectonic joint sets formed while the Ohio Shale was in the oil window. The oil and wet gas generated from the Ohio Shale have since migrated through the subsurface joint systems into younger reservoirs.

  9. The morphology of flare phenomena, magnetic fields, and electric currents in active regions. II - NOAA active region 5747 (1989 October)

    NASA Technical Reports Server (NTRS)

    Leka, K. D.; Canfield, Richard C.; Mcclymont, A. N.; De La Beaujardiere, J.-F.; Fan, Yuhong; Tang, F.

    1993-01-01

    The paper describes October 1989 observations in NOAA Active Region 5747 of the morphology of energetic electron precipitation and high-pressure coronal flare plasmas of three flares and their relation to the vector magnetic field and vertical electric currents. The H-alpha spectroheliograms were coaligned with the vector magnetograms using continuum images of sunspots, enabling positional accuracy of a few arcsec. It was found that, during the gradual phase, the regions of the H-alpha flare that show the effects of enhanced pressure in the overlying corona often encompass extrema of the vertical current density, consistent with earlier work showing a close relationship between H-alpha emission and line-of-sight currents. The data are also consistent with the overall morphology and evolution described by erupting-filament models such as those of Kopp and Pneuman (1976) and Sturrock (1989).

  10. Plasma Beta Above a Solar Active Region: Rethinking the Paradigm

    NASA Technical Reports Server (NTRS)

    Gary, G. Allen; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    In this paper, we present a model of the plasma beta above an active region and discuss its consequences in terms of coronal magnetic field modeling. The beta-plasma model is representative and derived from a collection of sources. The resulting beta variation with height is used to emphasize the assumption that the magnetic pressure dominates over the plasma pressure must be carefully considered depending on what part of the solar atmosphere is being considered. This paper points out (1) that the paradigm that the coronal magnetic field can be constructed from a force-free magnetic field must be used in the correct context, since the forcefree region is sandwiched between two regions which have beta greater than 1, (2) that the chromospheric MgIICIV magnetic measurements occur near the beta-minimum, and (3) that, moving from the photosphere upwards, beta can return to 1 at relatively low coronal heights, e.g. R approximately 1.2R(sub)s.

  11. Chemical Fingerprints of Star Forming Regions and Active Galaxies

    NASA Astrophysics Data System (ADS)

    Pérez-Beaupuits, Juan-Pablo

    2010-10-01

    This thesis is devoted to the study of the physical conditions of the interstellar medium (ISM) in active galactic nuclei (AGNs) and Galactic star-forming regions, using mostly single-dish millimeter observations. I first study the excitation conditions of dense gas in a group of Seyfert galaxies using radiative transfer models (Chapter 2). I then study the galaxy NGC 1068, and try to distinguish signatures of the contributions from the AGN and the starburst ring by incorporating observations of high-J transitions of dense gas tracers (Chapter 3). Later, I venture into the mid-infrared spectral region to study different aspects of the AGN and starburst components in the galaxy NGC 4945 (Chapter 4). In Chapter 5 I delve into theoretical aspects of the dynamical evolution of gas in an AGN torus. I use a 3D hydrodynamic simulation with chemical abundances driven by X-rays. The aim is to understand the effects of X-ray irradiation by the AGN on the temperature, formation and destruction of the molecular gas. I finally explore a Galactic star-forming region, the Omega Nebula, with high resolution single dish observations, to study the properties of the warm gas and to constrain chemical models (Chapters 6 and 7).

  12. Behaviour of oscillations in loop structures above active regions

    NASA Astrophysics Data System (ADS)

    Kolobov, D. Y.; Kobanov, N. I.; Chelpanov, A. A.; Kochanov, A. A.; Anfinogentov, S. A.; Chupin, S. A.; Myshyakov, I. I.; Tomin, V. E.

    2015-12-01

    In this study we combine the multiwavelength ultraviolet-optical (Solar Dynamics Observatory, SDO) and radio (Nobeyama Radioheliograph, NoRH) observations to get further insight into space-frequency distribution of oscillations at different atmospheric levels of the Sun. We processed the observational data on NOAA 11711 active region and found oscillations propagating from the photospheric level through the transition region upward into the corona. The power maps of low-frequency (1-2 mHz) oscillations reproduce well the fan-like coronal structures visible in the Fe IX 171 Å line. High frequency oscillations (5-7 mHz) propagate along the vertical magnetic field lines and concentrate inside small-scale elements in the umbra and at the umbra-penumbra boundary. We investigated the dependence of the dominant oscillation frequency upon the distance from the sunspot barycentre to estimate inclination of magnetic tubes in higher levels of sunspots where it cannot be measured directly, and found that this angle is close to 40° above the umbra boundaries in the transition region.

  13. The Magnetic Classification of Solar Active Regions 1992-2015

    NASA Astrophysics Data System (ADS)

    Jaeggli, S. A.; Norton, A. A.

    2016-03-01

    The purpose of this Letter is to address a blindspot in our knowledge of solar active region (AR) statistics. To the best of our knowledge, there are no published results showing the variation of the Mount Wilson magnetic classifications as a function of solar cycle based on modern observations. We show statistics for all ARs reported in the daily Solar Region Summary from 1992 January 1 to 2015 December 31. We find that the α and β class ARs (including all sub-groups, e.g., βγ, βδ) make up fractions of approximately 20% and 80% of the sample, respectively. This fraction is relatively constant during high levels of activity however, an increase in the α fraction to about 35% and and a decrease in the β fraction to about 65% can be seen near each solar minimum and are statistically significant at the 2σ level. Over 30% of all ARs observed during the years of solar maxima were appended with the classifications γ and/or δ, while these classifications account for only a fraction of a percent during the years near the solar minima. This variation in the AR types indicates that the formation of complex ARs may be due to the pileup of frequent emergence of magnetic flux during solar maximum, rather than the emergence of complex, monolithic flux structures.

  14. Active Region Filaments Might Harbor Weak Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Díaz Baso, C. J.; Martínez González, M. J.; Asensio Ramos, A.

    2016-05-01

    Recent spectropolarimetric observations of active region filaments have revealed polarization profiles with signatures typical of the strong field Zeeman regime. The conspicuous absence in those observations of scattering polarization and Hanle effect signatures was then pointed out by some authors. This was interpreted as either a signature of mixed “turbulent” field components or as a result of optical thickness. In this article, we present a natural scenario to explain these Zeeman-only spectropolarimetric observations of active region (AR) filaments. We propose a two-component model, one on top of the other. Both components have horizontal fields, with the azimuth difference between them being close to 90°. The component that lies lower in the atmosphere is permeated by a strong field of the order of 600 G, while the upper component has much weaker fields, of the order of 10 G. The ensuing scattering polarization signatures of the individual components have opposite signs, so its combination along the line of sight reduces—and even can cancel out—the Hanle signatures, giving rise to an apparent Zeeman-only profile. This model is also applicable to other chromospheric structures seen in absorption above ARs.

  15. Magnetic field measurements in and above a limb active region

    NASA Astrophysics Data System (ADS)

    Philip, Judge

    2013-07-01

    We analyze spectropolarimetric data of a limb active region (NOAA 11302) obtained on September 22nd 2011 using the Facility Infrared Spectrometer (FIRS) at the Dunn Solar Telescope (DST). Stokes profiles including lines of Si I 1028.7 nm and He I 1083 nm were obtained in three scans over a 45"x75" area. Simultaneous narrow band Ca II K and G-band intensity data were acquired with a cadence of 5s at the DST. The He I data show not only typical active region polarization signatures, but also signatures in plumes -- cool post flare loops -- which extend many Mm into the corona across the visible limb. The plumes have remarkably uniform brightness, and the plume plasma is significantly Doppler shifted as it drains from the corona. Using carefully constructed observing and calibration sequences and applying Principal Component Analysis to remove instrumental artifacts, we achieved a polarization sensitivity approaching 0.02%. With this sensitivity we attempt to diagnose the vector magnetic fields and plasma properties of chromospheric and cool coronal material in and above NOAA 11302. Inversions using various radiative transfer models in the HAZEL code are remarkably consistent with the idea that plume spectra are formed in a simple, slab-like geometry, but that the ``disk'' spectra are formed under more traditional models (Milne-Eddington). The inverted magnetic data of He I lines are compared with photospheric inversions of DST Si I and Fe I data from the Solar Dynamics Observatory.

  16. High power VCSEL device with periodic gain active region

    NASA Astrophysics Data System (ADS)

    Ning, Y. Q., II; Qin, L.; Sun, Y. F.; Li, T.; Cui, J. J.; Peng, B.; Liu, G. Y.; Zhang, Y.; Liu, Y.; Wang, L. J.; Cui, D. F.; Xu, Z. Y.

    2007-11-01

    High power vertical cavity surface emitting lasers with large aperture have been fabricated through improving passivation, lateral oxidation and heat dissipation techniques. Different from conventional three quantum well structure, a periodic gain active region with nine quantum wells was incorporated into the VCSEL structure, with which high efficiency and high power operation were expected. The nine quantum wells were divided into three groups with each of them located at the antinodes of the cavity to enhance the coupling between the optical field and the gain region. Large aperture and bottom-emitting configuration was used to improve the beam quality and the heat dissipation. A maximum output power of 1.4W was demonstrated at CW operation for a 400μm-diameter device. The lasing wavelength shifted to 995.5nm with a FWHM of 2nm at a current of 4.8A due to the internal heating and the absence of active water cooling. A ring-shape farfield pattern was induced by the non-homogeneous lateral current distribution in large diameter device. The light intensity at the center of the ring increased with increasing current. A symmetric round light spot at the center and single transverse mode operation with a divergence angle of 16° were observed with current beyond 4.8A.

  17. 77 FR 16222 - Agency Information Collection Activities; Proposed Collection; Comment Request; Generator...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-20

    ... AGENCY Agency Information Collection Activities; Proposed Collection; Comment Request; Generator... this action are private as well as State, Local, or Tribal Governments. Title: Generator Standards... Agency (EPA) has finalized an alternative set of generator requirements applicable to laboratories...

  18. Instant Stereoscopic Tomography of Active Regions with STEREO/EUVI

    NASA Astrophysics Data System (ADS)

    Aschwanden, M. J.; Wuelser, J.; Nitta, N.; Lemen, J.; Sandman, A.

    2008-12-01

    We develop a novel 3D reconstruction method of the coronal plasma of an active region by combining stereoscopic triangulation of loops with density and temperature modeling of coronal loops with a filling factor equivalent to tomographic volume rendering. Because this method requires only a stereoscopic image pair in multiple temperature filters, which are sampled within ~1 minute with the recent STEREO/EUVI instrument, this method is about 4 orders of magnitude faster than conventional solar rotation-based tomography. We reconstruct the 3D density and temperature distribution of active region NOAA 10955 by stereoscopic triangulation of 70 loops, which are used as a skeleton for a 3D field interpolation of some 7000 loop components, leading to a 3D model that reproduces the observed fluxes in each stereosocpic image pair with an accuracy of a few percent (of the average flux) in each pixel. With the stereoscopic tomography we infer also a differential emission measure (DEM) distribution over the entire temperature range of T~0.01-10 MK, with predictions for the transition region and hotter corona in soft X-rays. The tomographic 3D model provides also large statistics of physical parameters. We find that the EUV loops with apex temperatures of T = 1- 3 MK tend to be super-hydrostatic, while hotter loops with T = 4-7 MK are near-hydrostatic. The new 3D reconstruction model is fully independent of any magnetic field data and is promising for future tests of theoretical magnetic field models and coronal heating models.

  19. Metabolism of a highly selective gelatinase inhibitor generates active metabolite.

    PubMed

    Lee, Mijoon; Villegas-Estrada, Adriel; Celenza, Giuseppe; Boggess, Bill; Toth, Marta; Kreitinger, Gloria; Forbes, Christopher; Fridman, Rafael; Mobashery, Shahriar; Chang, Mayland

    2007-11-01

    (4-Phenoxyphenylsulfonyl)methylthiirane (inhibitor 1) is a highly selective inhibitor of gelatinases (matrix metalloproteinases 2 and 9), which is showing considerable promise in animal models for cancer and stroke. Despite demonstrated potent, selective, and effective inhibition of gelatinases both in vitro and in vivo, the compound is rapidly metabolized, implying that the likely activity in vivo is due to a metabolite rather than the compound itself. To this end, metabolism of inhibitor 1 was investigated in in vitro systems. Four metabolites were identified by LC/MS-MS and the structures of three of them were further validated by comparison with authentic synthetic samples. One metabolite, 4-(4-thiiranylmethanesulfonylphenoxy)phenol (compound 21), was generated by hydroxylation of the terminal phenyl group of 1. This compound was investigated in kinetics of inhibition of several matrix metalloproteinases. This metabolite was a more potent slow-binding inhibitor of gelatinases (matrix metalloproteinase-2 and matrix metalloproteinase-9) than the parent compound 1, but it also served as a slow-binding inhibitor of matrix metalloproteinase-14, the upstream activator of matrix metalloproteinase-2. PMID:17927722

  20. Improved catalytic activity of laser generated bimetallic and trimetallic nanoparticles.

    PubMed

    Singh, Rina; Soni, R K

    2014-09-01

    We report synthesis of silver nanoparticles, bimetallic (Al2O3@Ag) nanoparticles and trimetallic (Al2O3@AgAu) nanoparticles by nanosecond pulse laser ablation (PLA) in deionized water. Two-step laser ablation methodologies were adopted for the synthesis of bi- and tri-metallic nanoparticles. In this method a silver or gold target was ablated in colloidal solution of γ-alumina nanoparticles prepared by PLA. The TEM image analysis of bimetallic and trimetallic particles reveals deposition of fine silver particles and Ag-Au alloy particles, respectively, on large alumina particles. The laser generated nanoparticles were tested for catalytic reduction of 4-nitrophenol to 4-aminophenol and showed excellent catalytic behaviour. The catalytic rate was greatly improved by incorporation of additional metal in silver nanoparticles. The catalytic efficiency of trimetallic Al2O3@AgAu for reduction of 4-nitrophenol to 4-aminophenol was remarkably enhanced and the catalytic reaction was completed in just 5 sec. Even at very low concentration, both Al2O3@Ag nanoparticles and Al2O3@AgAu nanoparticles showed improved rate of catalytic reduction than monometallic silver nanoparticles. Our results demonstrate that alumina particles in the solution not only provide the active sites for particle dispersion but also improve the catalytic activity. PMID:25924343

  1. Photospheric electric current and transition region brightness within an active region

    NASA Technical Reports Server (NTRS)

    Deloach, A. C.; Hagyard, M. J.; Rabin, D.; Moore, R. L.; Smith, B. J., Jr.; West, E. A.; Tandberg-Hanssen, E.

    1984-01-01

    Distributions of vertical electrical current density J(z) calculated from vector measurements of the photospheric magnetic field are compared with ultraviolet spectroheliograms to investigate whether resistive heating is an important source of enhanced emission in the transition region. The photospheric magnetic fields in Active Region 2372 were measured on April 6 and 7, 1980 with the Marshall Space Flight Center vector magnetograph; ultraviolet wavelength spectroheliograms (L-alpha and N V 1239 A) were obtained with the UV Spectrometer and Polarimeter experiment aboard the Solar Maximum Mission satellite. Spatial registration of the J(z) (5 arcsec resolution) and UV (3 arcsec resolution) maps indicates that the maximum current density is cospatial with a minor but persistent UV enhancement, but there is little detected current associated with other nearby bright areas. It is concluded that, although resistive heating may be important in the transition region, the currents responsible for the heating are largely unresolved in the present measurements and have no simple correlation with the residual current measured on 5-arcsec scales.

  2. Efficient swimmers use bending kinematics to generate low pressure regions for suction-based swimming thrust

    NASA Astrophysics Data System (ADS)

    Colin, Sean; Gemmell, Brad; Costello, John; Morgan, Jennifer; Dabiri, John

    2015-11-01

    A longstanding tenet in the conceptualization of animal swimming is that locomotion occurs by pushing against the surrounding water. Implicit in this perspective is the assumption that swimming involves lateral body accelerations that generate locally elevated pressures in the fluid, in order to achieve the expected downstream push of the surrounding water against the ambient pressure. Here we show that to the contrary, efficient swimming animals primarily pull themselves through the water by creating localized regions of low pressure via waves of body surface rotation that generate vortices. These effects are observed using laser diagnostics applied to normal and spinally-transected lampreys. The results suggest rethinking evolutionary adaptations observed in swimming animals as well as the mechanistic basis for bio-inspired underwater vehicles. NSF CBET (1510929).

  3. Targeted enrichment of genomic DNA regions for next-generation sequencing

    PubMed Central

    ElSharawy, Abdou; Sauer, Sascha; van Helvoort, Joop M.L.M.; van der Zaag, P.J.; Franke, Andre; Nilsson, Mats; Lehrach, Hans; Brookes, Anthony J.

    2011-01-01

    In this review, we discuss the latest targeted enrichment methods and aspects of their utilization along with second-generation sequencing for complex genome analysis. In doing so, we provide an overview of issues involved in detecting genetic variation, for which targeted enrichment has become a powerful tool. We explain how targeted enrichment for next-generation sequencing has made great progress in terms of methodology, ease of use and applicability, but emphasize the remaining challenges such as the lack of even coverage across targeted regions. Costs are also considered versus the alternative of whole-genome sequencing which is becoming ever more affordable. We conclude that targeted enrichment is likely to be the most economical option for many years to come in a range of settings. PMID:22121152

  4. Feasibility study on introduction of the bio-fuel power generation in tropical regions

    NASA Astrophysics Data System (ADS)

    1993-03-01

    Study is made on feasibility of introducing the bio-fuel power generation in tropical regions, especially in South East Asia including Okinawa and South America. Biomass promising as bio-fuel is bagasse and palm oil mill dregs; and bagasse is found to be advantageous to the use for large-scaled power generation. Prospective uses of bagasse are a combined use of gasification process and gas turbine power generation, an effective use of gas turbine exhaust heat at sugar cane factories, and a use of the system to be developed which totalizes these two. As to how to carry out the R and D project, since the gasification power generation process itself is a high technology and has partially unknown fields, it is desirable that research and development are conducted in such technologically developed countries as Japan (Okinawa). A developmental plan, therefore, is worked out as such that a pilot plant of approximately 3000kW is to be constructed in Okinawa because the period for bagasse production is at least 3 months there, and a commercial-scale plant is to be constructed and operated in such big bagasse-producing countries as Brazil.

  5. Cost analysis for compliance with EPA's regional NOx emissions reductions for fossil-fired power generation

    SciTech Connect

    Smith, D.; Mann, A.; Ward, J.; Ramezan, M.

    1999-07-01

    To achieve a more stringent ambient-air ozone standard promulgated in 1997, the U.S. EPA has established summer NOx emissions limits for fossil-fired electric power generating units in the Ozone Transport Rulemaking region, consisting of 22 eastern and midwestern states and the District of Columbia. These jurisdictions are required to submit State Implementation Plans by September 1999 in response to EPA's rule, with compliance required by 2007. There are 1757 affected units in this region. In the present study, projected state-by-state growth rates for power production are used to estimate power production and NOx emissions by unit in the year 2007. NOx emissions reductions expected by January 1, 2000 due to Title IV compliance are estimated, leaving a substantial balance of emissions reductions to be achieved by post-combustion NOx control. Cost estimates are developed for achieving these remaining reductions.

  6. Using radiation hybrids to generate region-specific markers for human chromosome 9

    SciTech Connect

    Britt, D.E.; Mark, H.F.L.; Nebres, M.

    1994-09-01

    The production of sequence tagged sites and polymorphic markers is an important step in generating a physical map of the human genome and identifying loci involved in genetic diseases. Our work involves the physical mapping of the short arm of human chromosome 9, the site of at least one tumor supressor gene, as well as the locus involved in cartilage hair hypoplasia. Our goal is to increase the number of markers available for 9p, using a panel of radiation hybrids we have constructed and characterized. The hybrids were generated from a monochromosomal hybrid that contains human chromosome 9 marked with a retroviral vector. Radiation hybrids were produced that contain overlapping regions of the chromosome surrounding the site of retroviral integration. In order to generate markers specific for the short arm, Alu-PCR products from a radiation hybrid containing only 9p were cloned. Clones were mapped back to a subpanel of hybrids and grouped into intervals. By using a hybrid subpanel containing overlapping portions 9p, we are able to identify clones from defined regions. DNA from the clones was sequenced and this information used to generate sequence tagged sites. We have also developed a number of new polymorphic markers, taking advantage of the high degree of polymorphism of the 3{prime} end of each Alu sequence. For each polymorphic marker, a specific primer was designed from the cloned DNA and then paired with an Alu primer. These primer pairs were used to amplify DNA from unrelated individuals, in order to identify primer sets that detect useful polymorphisms. Both the STS and polymorphic markers will be extremely useful in the construction of a physical map of chromosome 9, and in the identification of genes on the short arm of the chromosome.

  7. Generation and reactivation of T-cell receptor A joining region pseudogenes in primates

    SciTech Connect

    Thiel, C.; Lanchbury, J.S.; Otting, N.

    1996-06-01

    Tandemly duplicated T-cell receptor (Tcr) AJ (J{alpha}) segments contribute significantly to TCRA chain junctional region diversity in mammals. Since only limited data exists on TCRA diversity in nonhuman primates, we examined the TCRAJ regions of 37 chimpanzee and 71 rhesus macaque TCRA cDNA clones derived from inverse polymerase chain reaction on peripheral blood mononuclear cell cDNA of healthy animals. Twenty-five different TCRAJ regions were characterized in the chimpanzee and 36 in the rhesus macaque. Each bears a close structural relationship to an equivalent human TCRAJ region. Conserved amino acid motifs are shared between all three species. There are indications that differences between nonhuman primates and humans exist in the generation of TCRAJ pseudogenes. The nucleotide and amino acid sequences of the various characterized TCRAJ of each species are reported and we compare our results to the available information on human genomic sequences. Although we provide evidence of dynamic processes modifying TCRAJ segments during primate evolution, their repertoire and primary structure appears to be relatively conserved. 21 refs., 2 figs.

  8. Demolition waste generation for development of a regional management chain model.

    PubMed

    Bernardo, Miguel; Gomes, Marta Castilho; de Brito, Jorge

    2016-03-01

    Even though construction and demolition waste (CDW) is the bulkiest waste stream, its estimation and composition in specific regions still faces major difficulties. Therefore new methods are required especially when it comes to make predictions limited to small areas, such as counties. This paper proposes one such method, which makes use of data collected from real demolition works and statistical information on the geographical area under study. Based on a correlation analysis between the demolition waste estimates and indicators such as population density, buildings ageing index, buildings density and land occupation type, relationships are established that can be used to determine demolition waste outputs in a given area. The derived models are presented and explained. This methodology is independent from the specific region with which it is exemplified (the Lisbon Metropolitan Area) and can therefore be applied to any region of the world, from the country to the county level. Generation of demolition waste data at the county level is the basis of the design of a systemic model for CDW management in a region. Future developments proposed include a mixed-integer linear programming formulation of such recycling network. PMID:26838607

  9. Paralleling power MOSFETs in their active region: Extended range of passively forced current sharing

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    1989-01-01

    A simple passive circuit that improves current balance in parallelled power MOSFETs that are not precisely matched and that are operated in their active region from a common gate drive are exhibited. A nonlinear circuit consisting of diodes and resistors generates the differential gate potential required to correct for unbalance while maintaining low losses over a range of current. Also application of a thin tape wound magnetic core to effect dynamic current balance is reviewed, and a simple theory is presented showing that for operation in the active region the branch currents tend to revert to their normal unbalanced values even if the core is not driven into saturation. Results of several comparative experiments are given.

  10. Photonic crystal lasers using wavelength-scale embedded active region

    NASA Astrophysics Data System (ADS)

    Matsuo, Shinji; Sato, Tomonari; Takeda, Koji; Shinya, Akihiko; Nozaki, Kengo; Kuramochi, Eiichi; Taniyama, Hideaki; Notomi, Masaya; Fujii, Takuro; Hasebe, Koichi; Kakitsuka, Takaaki

    2014-01-01

    Lasers with ultra-low operating energy are desired for use in chip-to-chip and on-chip optical interconnects. If we are to reduce the operating energy, we must reduce the active volume. Therefore, a photonic crystal (PhC) laser with a wavelength-scale cavity has attracted a lot of attention because a PhC provides a large Q-factor with a small volume. To improve this device's performance, we employ an embedded active region structure in which the wavelength-scale active region is buried with an InP PhC slab. This structure enables us to achieve effective confinement of both carriers and photons, and to improve the thermal resistance of the device. Thus, we have obtained a large external differential quantum efficiency of 55% and an output power of -10 dBm by optical pumping. For electrical pumping, we use a lateral p-i-n structure that employs Zn diffusion and Si ion implantation for p-type and n-type doping, respectively. We have achieved room-temperature continuous-wave operation with a threshold current of 7.8 µA and a maximum 3 dB bandwidth of 16.2 GHz. The results of an experimental bit error rate measurement with a 10 Gbit s-1 NRZ signal reveal the minimum operating energy for transferring a single bit of 5.5 fJ. These results show the potential of this laser to be used for very short reach interconnects. We also describe the optimal design of cavity quality (Q) factor in terms of achieving a large output power with a low operating energy using a calculation based on rate equations. When we assume an internal absorption loss of 20 cm-1, the optimized coupling Q-factor is 2000.

  11. Repetitive Transcranial Magnetic Stimulation Activates Specific Regions in Rat Brain

    NASA Astrophysics Data System (ADS)

    Ji, Ru-Rong; Schlaepfer, Thomas E.; Aizenman, Carlos D.; Epstein, Charles M.; Qiu, Dike; Huang, Justin C.; Rupp, Fabio

    1998-12-01

    Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique to induce electric currents in the brain. Although rTMS is being evaluated as a possible alternative to electroconvulsive therapy for the treatment of refractory depression, little is known about the pattern of activation induced in the brain by rTMS. We have compared immediate early gene expression in rat brain after rTMS and electroconvulsive stimulation, a well-established animal model for electroconvulsive therapy. Our result shows that rTMS applied in conditions effective in animal models of depression induces different patterns of immediate-early gene expression than does electroconvulsive stimulation. In particular, rTMS evokes strong neural responses in the paraventricular nucleus of the thalamus (PVT) and in other regions involved in the regulation of circadian rhythms. The response in PVT is independent of the orientation of the stimulation probe relative to the head. Part of this response is likely because of direct activation, as repetitive magnetic stimulation also activates PVT neurons in brain slices.

  12. Women's income generation activities in Merowe Province, Northern State, Sudan.

    PubMed

    Pitamber, S; Osama, S

    1994-06-01

    Merowe province in rural northern Sudan has been divided into three local government council areas: Merowe, Karima, and Ed Debba. A government program was instituted to increase the welfare of residents and food production. A baseline survey of 490 respondents was conducted in order to ascertain how illiterate women viewed development in the area and to provide useful information for program design and implementation. Women from 24 villages were administered questionnaires, observed in their daily activities, and engaged in discussion in a local meeting place. Discussions were also held with members of the local Popular Committee. Demographic information was very sketchy about age, and 48% had no formal education in writing and reading. General reading and writing skills of the remainder were very poor. There were 500 female children and 502 male children, and the sex ratio varied among the 3 council areas. 52% were married and 14% were divorced or widowed and living with relatives. The average monthly income was from Ls. 700 to Ls. 3000 based on reports from only 59.3% of respondents. Most of the women had skills in food processing and 25.7% were skilled in handicrafts. Water was obtained primarily from local wells and not decontaminated before use. Pit latrines were the standard. One bathing facility was available in the compound for the entire council area. Health units were either in each village or within 20-30 minutes walk. Child mortality was 4.3% in Merowe province. 77 children 0-5 years old died out of a total of 1002 live births. Life expectancy was 41-50 years for women and 61-70 years for men. Cleanliness and healthful eating were observed. 58% owned no land; plots were under 5 feddans and usually half a feddan. 92.1% had no bank account and 90% had no experience with loans. 70.2% were indifferent about involvement in an income generation program. 26% were interested in part-time participation. Only 3.9% desired full-time participation. 8.6% said they

  13. Comparison of Solar Active Region Complexity Andgeomagnetic Activity from 1996 TO 2014

    NASA Astrophysics Data System (ADS)

    Tanskanen, E. I.; Nikbakhsh, S.; Perez-Suarez, D.; Hackman, T.

    2015-12-01

    We have studied the influence of magnetic complexity of solar Active Regions (ARs)on geomagnetic activity from 1996 to 2014. Sunspots are visual indicators of ARswhere the solar magnetic field is disturbed. We have used International, American,Space Environment Service Center (SESC) and Space Weather Prediction Center(SWPC) sunspot numbers to examine ARs. Major manifestations of solar magneticactivity, such as flares and Coronal Mass Ejections (CMEs), are associated withARs. For this study we chose the Mount Wilson scheme. It classifies ARs in terms oftheir magnetic topology from the least complex (?) to the most complex one ( ?).Several cases have been found where the more complex structures produce strongerflares and CMEs than the less complex ones. We have a list of identified substormsavailable with different phases and their durations. This will be compared to ourmagnetic complexity data to analyse the effects of active region magnetic complexityto the magnetic activity on the vicinity of the Earth.

  14. Analysis of mixtures using next generation sequencing of mitochondrial DNA hypervariable regions

    PubMed Central

    Kim, Hanna; Erlich, Henry A.; Calloway, Cassandra D.

    2015-01-01

    Aim To apply massively parallel and clonal sequencing (next generation sequencing or NGS) to the analysis of forensic mixed samples. Methods A duplex polymerase chain reaction (PCR) assay targeting the mitochondrial DNA (mtDNA) hypervariable regions I/II (HVI/HVII) was developed for NGS analysis on the Roche 454 GS Junior instrument. Eight sets of multiplex identifier-tagged 454 fusion primers were used in a combinatorial approach for amplification and deep sequencing of up to 64 samples in parallel. Results This assay was shown to be highly sensitive for sequencing limited DNA amounts ( ~ 100 mtDNA copies) and analyzing contrived and biological mixtures with low level variants ( ~ 1%) as well as “complex” mixtures (≥3 contributors). PCR artifact “hybrid” sequences generated by jumping PCR or template switching were observed at a low level (<2%) in the analysis of mixed samples but could be eliminated by reducing the PCR cycle number. Conclusion This study demonstrates the power of NGS technologies targeting the mtDNA HVI/HVII regions for analysis of challenging forensic samples, such as mixtures and specimens with limited DNA. PMID:26088845

  15. REGION 4-SESD TRAINING ACTIVITIES: OCTOBER 2006 – JULY 2007

    EPA Science Inventory

    Each year, the Region 4 Science and Ecosystem Support Division (SESD) provides training and technical assistance to hundreds of students. Training courses are presented to Region 4 employees, Region 4 States, Indian Tribes, Universities, Federal Agencies, and other audiences outs...

  16. Generation and Characterization of the Western Regional Research Center Brachypodium T-DNA Insertional Mutant Collection

    PubMed Central

    Gordon, Sean P.; Guttman, Mara E.; Thilmony, Roger; Lazo, Gerard R.; Gu, Yong Q.; Vogel, John P.

    2012-01-01

    The model grass Brachypodium distachyon (Brachypodium) is an excellent system for studying the basic biology underlying traits relevant to the use of grasses as food, forage and energy crops. To add to the growing collection of Brachypodium resources available to plant scientists, we further optimized our Agrobacterium tumefaciens-mediated high-efficiency transformation method and generated 8,491 Brachypodium T-DNA lines. We used inverse PCR to sequence the DNA flanking the insertion sites in the mutants. Using these flanking sequence tags (FSTs) we were able to assign 7,389 FSTs from 4,402 T-DNA mutants to 5,285 specific insertion sites (ISs) in the Brachypodium genome. More than 29% of the assigned ISs are supported by multiple FSTs. T-DNA insertions span the entire genome with an average of 19.3 insertions/Mb. The distribution of T-DNA insertions is non-uniform with a larger number of insertions at the distal ends compared to the centromeric regions of the chromosomes. Insertions are correlated with genic regions, but are biased toward UTRs and non-coding regions within 1 kb of genes over exons and intron regions. More than 1,300 unique genes have been tagged in this population. Information about the Western Regional Research Center Brachypodium insertional mutant population is available on a searchable website (http://brachypodium.pw.usda.gov) designed to provide researchers with a means to order T-DNA lines with mutations in genes of interest. PMID:23028431

  17. On the modified active region design of interband cascade lasers

    SciTech Connect

    Motyka, M.; Ryczko, K.; Dyksik, M.; Sęk, G.; Misiewicz, J.; Weih, R.; Dallner, M.; Kamp, M.; Höfling, S.

    2015-02-28

    Type II InAs/GaInSb quantum wells (QWs) grown on GaSb or InAs substrates and designed to be integrated in the active region of interband cascade lasers (ICLs) emitting in the mid infrared have been investigated. Optical spectroscopy, combined with band structure calculations, has been used to probe their electronic properties. A design with multiple InAs QWs has been compared with the more common double W-shaped QW and it has been demonstrated that it allows red shifting the emission wavelength and enhancing the transition oscillator strength. This can be beneficial for the improvements of the ICLs performances, especially when considering their long-wavelength operation.

  18. Chromospheric magnetic fields of an active region filament

    NASA Astrophysics Data System (ADS)

    Xu, Z.; Solanki, S.; Lagg, A.

    2012-06-01

    Vector magnetic fields of an active region filament are co-spatially and co-temporally mapped in photosphere and upper chromosphere, by using spectro-polarimetric observations made by Tenerife Infrared Polarimeter (TIP II) at the German Vacuum Tower Telescope (VTT). A Zeeman-based ME inversion is performed on the full Stokes vectors of both the photospheric Si I 1082.7 nm and the chromospheric He I 1083.0 nm lines. We found that the strong magnetic fields, with the field strength of 600 - 800 G in the He I line formation height, are not uncommon among AR filaments. But such strong magnetic field is not always found in AR filaments.

  19. Active region studies with coordinated SOHO, microwave, and magnetograph observations

    NASA Technical Reports Server (NTRS)

    Holman, Gordon D.

    1992-01-01

    The scientific justification for an observing campaign to study the quantitative magnetic and plasma properties of coronal loops in active regions is presented. The SOHO (Solar and Heliospheric Observatory) instruments of primary relevance are CDS (Coronal Diagnostic Spectrometer), EIT, SUMER (Solar Ultraviolet Measurement of Emitted Radiation), and MDI. The primary ground based instruments would be the VLA (Very Large Array), the Owens Valley Radio Observatory, and vector and longitudinal field magnetographs. Similar campaigns have successfully been carried out with the Solar Maximum Mission x-ray polychromator and the Soft X-ray Imaging Sounding Rocket Payload (CoMStOC '87), the Goddard Solar EUV Rocket Telescope and Spectrograph, the Lockheed Solar Plasma Diagnostics Experiment rocket payload, and the Soft X-ray Telescope in Yohkoh (CoMStoc '92). The scientific payoff from such a campaign is discussed in light of the results from these previous campaigns.

  20. Active Control of Fan-Generated Tone Noise

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.

    1995-01-01

    This paper reports on an experiment to control the noise radiated from the inlet of a ducted fan using a time domain active adaptive system. The control ,sound source consists of loudspeakers arranged in a ring around the fan duct. The error sensor location is in the fan duct. The purpose of this experiment is to demonstrate that the in-duct error sensor reduces the mode spillover in the far field, thereby increasing the efficiency of the control system. The control system is found to reduce the blade passage frequency tone significantly in the acoustic far field when the mode orders of the noise source and of the control source are the same, when the dominant wave in the duct is a plane wave. The presence of higher order modes in the duct reduces the noise reduction efficiency, particularly near the mode cut-on where the standing wave component is strong, but the control system converges stably. The control system is stable and converges when the first circumferential mode is generated in the duct. The control system is found to reduce the fan noise in the far field on an arc around the fan inlet by as much as 20 dB with none of the sound amplification associated with mode spillover.

  1. Statistical downscaling and future scenario generation of temperatures for Pakistan Region

    NASA Astrophysics Data System (ADS)

    Kazmi, Dildar Hussain; Li, Jianping; Rasul, Ghulam; Tong, Jiang; Ali, Gohar; Cheema, Sohail Babar; Liu, Luliu; Gemmer, Marco; Fischer, Thomas

    2015-04-01

    Finer climate change information on spatial scale is required for impact studies than that presently provided by global or regional climate models. It is especially true for regions like South Asia with complex topography, coastal or island locations, and the areas of highly heterogeneous land-cover. To deal with the situation, an inexpensive method (statistical downscaling) has been adopted. Statistical DownScaling Model (SDSM) employed for downscaling of daily minimum and maximum temperature data of 44 national stations for base time (1961-1990) and then the future scenarios generated up to 2099. Observed as well as Predictors (product of National Oceanic and Atmospheric Administration) data were calibrated and tested on individual/multiple basis through linear regression. Future scenario was generated based on HadCM3 daily data for A2 and B2 story lines. The downscaled data has been tested, and it has shown a relatively strong relationship with the observed in comparison to ECHAM5 data. Generally, the southern half of the country is considered vulnerable in terms of increasing temperatures, but the results of this study projects that in future, the northern belt in particular would have a possible threat of increasing tendency in air temperature. Especially, the northern areas (hosting the third largest ice reserves after the Polar Regions), an important feeding source for Indus River, are projected to be vulnerable in terms of increasing temperatures. Consequently, not only the hydro-agricultural sector but also the environmental conditions in the area may be at risk, in future.

  2. Potential Impacts of Plug-in Hybrid Electric Vehicles on Regional Power Generation

    SciTech Connect

    Hadley, Stanton W; Tsvetkova, Alexandra A

    2008-01-01

    Plug-in hybrid electric vehicles (PHEVs) are being developed around the world, with much work aiming to optimize engine and battery for efficient operation, both during discharge and when grid electricity is available for recharging. However, the general expectation has been that the grid will not be greatly affected by the use of PHEVs because the recharging will occur during off-peak hours, or the number of vehicles will grow slowly enough so that capacity planning will respond adequately. This expectation does not consider that drivers will control the timing of recharging, and their inclination will be to plug in when convenient, rather than when utilities would prefer. It is important to understand the ramifications of adding load from PHEVs onto the grid. Depending on when and where the vehicles are plugged in, they could cause local or regional constraints on the grid. They could require the addition of new electric capacity and increase the utilization of existing capacity. Usage patterns of local distribution grids will change, and some lines or substations may become overloaded sooner than expected. Furthermore, the type of generation used to meet the demand for recharging PHEVs will depend on the region of the country and the timing of recharging. This paper analyzes the potential impacts of PHEVs on electricity demand, supply, generation structure, prices, and associated emission levels in 2020 and 2030 in 13 regions specified by the North American Electric Reliability Corporation (NERC) and the U.S. Department of Energy's (DOE's) Energy Information Administration (EIA), and on which the data and analysis in EIA's Annual Energy Outlook 2007 are based (Figure ES-1). The estimates of power plant supplies and regional hourly electricity demand come from publicly available sources from EIA and the Federal Energy Regulatory Commission. Electricity requirements for PHEVs are based on analysis from the Electric Power Research Institute, with an optimistic

  3. Numerical simulation of superhalo electrons generated by magnetic reconnection in the solar wind source region

    NASA Astrophysics Data System (ADS)

    Yang, Li-Ping; Wang, Ling-Hua; He, Jian-Sen; Tu, Chuan-Yi; Zhang, Shao-Hua; Zhang, Lei; Feng, Xue-Shang

    2015-03-01

    Superhalo electrons appear to be continuously present in the interplanetary medium, even during very quiet times, with a power-law spectrum at energies above ˜2keV. Here we numerically investigate the generation of superhalo electrons by magnetic reconnection in the solar wind source region, using magnetohydrodynamics and test particle simulations for both single X-line reconnection and multiple X-line reconnection. We find that the direct current electric field, produced in the magnetic reconnection region, can accelerate electrons from an initial thermal energy of T ˜ 105 K up to hundreds of keV. After acceleration, some of the accelerated electrons, together with the nascent solar wind flow driven by the reconnection, propagate upwards along the newly-opened magnetic field lines into interplanetary space, while the rest move downwards into the lower atmosphere. Similar to the observed superhalo electrons at 1AU, the flux of upward-traveling accelerated electrons versus energy displays a power-law distribution at ˜ 2-100 keV, f(E) ˜ E-δ, with a δ of ˜ 1.5 - 2.4. For single (multiple) X-line reconnection, the spectrum becomes harder (softer) as the anomalous resistivity parameter α (uniform resistivity η) increases. These modeling results suggest that the acceleration in the solar wind source region may contribute to superhalo electrons. Supported by the National Natural Science Foundation of China.

  4. Activation of the dentate nucleus in a verb generation task: A 7T MRI study.

    PubMed

    Thürling, M; Küper, M; Stefanescu, R; Maderwald, S; Gizewski, E R; Ladd, M E; Timmann, D

    2011-08-01

    There is increasing evidence of a topographic organization within the human cerebellar cortex for motor and non-motor functions. Likewise, a subdivision of the dentate nucleus in a more dorsal and rostral motor domain and a more ventral and caudal non-motor domain has been proposed by Dum and Strick (2003) based on anatomical studies in monkey. In humans, however, very little is known about topographic organization within the dentate nucleus. Activation of the dentate nucleus in a verb generation task was examined in young and healthy subjects using ultra-highfield 7T functional magnetic resonance imaging (fMRI) with its increase in signal-to-noise ratio. Data of 17 subjects were included in statistical analysis. Subjects were asked to (i) read words (nouns) aloud presented on a screen, (ii) silently read the same nouns, (iii) silently generate the appropriate verbs to the same nouns and (iv) to silently repeat the names of the months. A block design was used. For image processing, a recently developed region of interest (ROI) driven normalization method of the dentate nuclei was applied. Activation related to motor speech (contrast aloud reading minus silent reading) was strongest in the rostral parts of the dentate nucleus. Dorsorostral activations were present bilaterally. Activation related to verb generation (contrast verb generation minus silent reading) was found in the ventrocaudal parts of the dentate nucleus on the right. The present findings are in good accordance with the anatomical data in monkeys and suggest that the human dentate nucleus can be subdivided into a rostral and more dorsal motor domain and a ventrocaudal non-motor domain. PMID:21640191

  5. Long-Period ULF Wave Activity in the Cusp Region

    NASA Astrophysics Data System (ADS)

    Pilipenko, V.; Belakhovsky, V.; Engebretson, M. J.; Kozlovsky, A.

    2013-12-01

    We compare simultaneous observations of long-period ULF wave activity from the Svalbard/IMAGE and Greenland fluxgate magnetometer profiles covering the expected cusp geomagnetic latitudes. Irregular Pulsations at Cusp Latitudes (IPCL) and narrow-band Pc5 waves are found to be a ubiquitous element of ULF activity in the dayside high-latitude region. To identify the ionospheric projections of the cusp, we use the width of the return signal of the SuperDARN radar covering the Svalbard archipelago, predictions of empirical cusp models, and augmented whenever possible by DMSP identification of magnetospheric boundary domains. The meridional spatial structure of IPCL/Pc5 pulsation spectral power has been found to have a localized latitudinal peak, but not under the cusp proper as was previously thought, but several degrees southward from the equatorward cusp boundary. Possible mechanisms and their relevance to observational data are discussed. The occurrence of IPCL and Pc5 waves in the dayside boundary layers is a challenge to modelers, because so far their mechanism has not been firmly identified.

  6. Regional Triggering of Volcanic Activity Following Large Magnitude Earthquakes

    NASA Astrophysics Data System (ADS)

    Hill-Butler, Charley; Blackett, Matthew; Wright, Robert

    2015-04-01

    There are numerous reports of a spatial and temporal link between volcanic activity and high magnitude seismic events. In fact, since 1950, all large magnitude earthquakes have been followed by volcanic eruptions in the following year - 1952 Kamchatka M9.2, 1960 Chile M9.5, 1964 Alaska M9.2, 2004 & 2005 Sumatra-Andaman M9.3 & M8.7 and 2011 Japan M9.0. While at a global scale, 56% of all large earthquakes (M≥8.0) in the 21st century were followed by increases in thermal activity. The most significant change in volcanic activity occurred between December 2004 and April 2005 following the M9.1 December 2004 earthquake after which new eruptions were detected at 10 volcanoes and global volcanic flux doubled over 52 days (Hill-Butler et al. 2014). The ability to determine a volcano's activity or 'response', however, has resulted in a number of disparities with <50% of all volcanoes being monitored by ground-based instruments. The advent of satellite remote sensing for volcanology has, therefore, provided researchers with an opportunity to quantify the timing, magnitude and character of volcanic events. Using data acquired from the MODVOLC algorithm, this research examines a globally comparable database of satellite-derived radiant flux alongside USGS NEIC data to identify changes in volcanic activity following an earthquake, February 2000 - December 2012. Using an estimate of background temperature obtained from the MODIS Land Surface Temperature (LST) product (Wright et al. 2014), thermal radiance was converted to radiant flux following the method of Kaufman et al. (1998). The resulting heat flux inventory was then compared to all seismic events (M≥6.0) within 1000 km of each volcano to evaluate if changes in volcanic heat flux correlate with regional earthquakes. This presentation will first identify relationships at the temporal and spatial scale, more complex relationships obtained by machine learning algorithms will then be examined to establish favourable

  7. Freezing Rain Diagnostic Study Over Eastern Canada Using the 5th Generation Canadian Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Bresson, É.; Paquin, D.; Laprise, R.; Theriault, J. M.; de Elía, R.

    2015-12-01

    Northeastern North America is often affected by freezing rain events during the cold season. They can have significant consequences (from road accidents, to severe power outages) despite their intensity and duration. The 1998 Ice Storm over Eastern Canada and Northeastern United States is an example of an extreme event with catastrophic consequences. A total of up to 150 mm of ice accumulated during 10 days were observed in some areas. This natural disaster has highlighted the need to better understand how such phenomena will evolve with future climate scenario. The goal is to investigate the feasibility of using regional climate modeling to diagnose the occurrence of freezing rain events over Quebec (Canada). To address this issue, we used the 5th generation of the Canadian Regional Climate Model (CRCM5), from 1979 to 2014. An empirical method (Bourgouin, 2000) developed to determine the type of winter precipitations was chosen to diagnose freezing rain events. The study focused in the Montreal area and the St. Lawrence River Valley (Quebec, Canada). The sensitivity of the model to horizontal resolution was explored by using three resolutions: 0.44°, 0.22° and 0.11°. In general, freezing rain was diagnosed consistently at all resolutions but the higher one (0.11°) produced more realistic results due to a better representation of the orography. Using the higher resolution, the results showed that the climatology of the freezing rain occurrence in the Montreal area is comparable to available observations. It also suggested that the role of the specific orography of the region with the St. Lawrence River Valley can impact the characteristics of freezing rain events in this area. Overall, this study will contribute to a better preparedness for such events in the future. High resolution regional climate simulations are essential to improve the reproduction of local scale orographically-forced phenomena.

  8. Agricultural pests under future climate conditions: downscaling of regional climate scenarios with a stochastic weather generator

    NASA Astrophysics Data System (ADS)

    Hirschi, M.; Stöckli, S.; Dubrovsky, M.; Spirig, C.; Rotach, M. W.; Calanca, P.; Samietz, J.

    2010-09-01

    As a consequence of current and projected climate change in temperate regions of Europe, agricultural pests and diseases are expected to occur more frequently and possibly to extend to previously unaffected regions. Given their economic and ecological relevance, detailed forecasting tools for various pests have been developed, which model the infestation depending on actual weather conditions. Assessing the future risk of pest-related damages therefore requires future weather data at high temporal and spatial resolution. In particular, pest forecast models are often not based on screen temperature and precipitation alone (i.e., the most generally projected climate variables), but might require input variables such as soil temperature, in-canopy net radiation or leaf wetness. Here, we use a stochastic weather and a re-sampling procedure for producing site-specific hourly weather data from regional climate change scenarios for 2050 in Switzerland. The climate change scenarios were derived from multi-model projections and provide probabilistic information on future regional changes in temperature and precipitation. Hourly temperature, precipitation and radiation data were produced by first generating daily weather data for these climate scenarios and then using a nearest neighbor re-sampling approach for creating realistic diurnal cycles. These hourly weather time series were then used for modeling important phases in the lifecycle of codling moth, the major insect pest in apple orchards worldwide. First results indicate a shift in the occurrence and duration of phases relevant for pest disease control for projected as compared to current climate (e.g. the flight of the codling moth starts about ten days earlier in future climate), continuing an already observed trend towards more favorable conditions for this insect during the last 20 years.

  9. 77 FR 24952 - Agency Information Collection Activities; Proposed Collection; Comment Request; Regional Haze...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-26

    ... ICR (August 26, 2009; 74 FR 43118). The last collection request anticipated the program progressing... AGENCY Agency Information Collection Activities; Proposed Collection; Comment Request; Regional Haze... organizations and facilities potentially regulated under the regional haze rule. Title: Regional...

  10. ON MAGNETIC ACTIVITY BAND OVERLAP, INTERACTION, AND THE FORMATION OF COMPLEX SOLAR ACTIVE REGIONS

    SciTech Connect

    McIntosh, Scott W.; Leamon, Robert J.

    2014-11-20

    Recent work has revealed a phenomenological picture of the how the ∼11 yr sunspot cycle of the Sun arises. The production and destruction of sunspots is a consequence of the latitudinal-temporal overlap and interaction of the toroidal magnetic flux systems that belong to the 22 yr magnetic activity cycle and are rooted deep in the Sun's convective interior. We present a conceptually simple extension of this work, presenting a hypothesis on how complex active regions can form as a direct consequence of the intra- and extra-hemispheric interaction taking place in the solar interior. Furthermore, during specific portions of the sunspot cycle, we anticipate that those complex active regions may be particularly susceptible to profoundly catastrophic breakdown, producing flares and coronal mass ejections of the most severe magnitude.

  11. Deleting the Redundant TSH Receptor C-Peptide Region Permits Generation of the Conformationally Intact Extracellular Domain by Insect Cells.

    PubMed

    Chen, Chun-Rong; Salazar, Larry M; McLachlan, Sandra M; Rapoport, Basil

    2015-07-01

    The TSH receptor (TSHR) extracellular domain (ECD) comprises a N-terminal leucine-rich repeat domain and an hinge region (HR), the latter contributing to ligand binding and critical for receptor activation. The crystal structure of the leucine-rich repeat domain component has been solved, but previous attempts to generate conformationally intact complete ECD or the isolated HR component for structural analysis have failed. The TSHR HR contains a C-peptide segment that is removed during spontaneous TSHR intramolecular cleavage into disulfide linked A- and B-subunits. We hypothesized that deletion of the redundant C-peptide would overcome the obstacle to generating conformationally intact TSHR ECD protein. Indeed, lacking the C-peptide region, the TSHR ECD (termed ECD-D1) and the isolated HR (termed HR-D1) were secreted into medium of insect cells infected with baculoviruses coding for these modified proteins. The identities of TSHR ECD-D1 and HR-D1 were confirmed by ELISA and immunoblotting using TSHR-specific monoclonal antibodies. The TSHR-ECD-D1 in conditioned medium was folded correctly, as demonstrated by its ability to inhibit radiolabeled TSH binding to the TSH holoreceptor. The TSHR ECD-D1 purification was accomplished in a single step using a TSHR monoclonal antibody affinity column, whereas the HR-D1 required a multistep protocol with a low yield. In conclusion, we report a novel approach to generate the TSHR ECD, as well as the isolated HR in insect cells, the former in sufficient amounts for structural studies. However, such studies will require previous complexing of the ECD with a ligand such as TSH or a thyroid-stimulating antibody. PMID:25860033

  12. The morphology of flare phenomena, magnetic fields, and electric currents in active regions. III - NOAA active region 6233 (1990 August)

    NASA Technical Reports Server (NTRS)

    De La Beaujardiere, J.-F.; Canfield, Richard C.; Leka, K. D.

    1993-01-01

    We investigate the spatial relationship between vertical electric currents and flare phenomena in NOAA Active Region 6233, which was observed 1990, August 28-31 at Mees Solar Observatory. The two flares studied are the 1N/M1.8 flare on August 28, 22:30 UT and the 1N/M1.6 flare on August 29, 20:35 UT. Using Stokes polarimetry we make magnetograms of the region and compute the vertical current density. Using H-alpha imaging spectroscopy we identify sites of intense nonthermal electron precipitation or of high coronal pressure. The precipitation in these flares is barely strong enough to be detectable. We find that both precipitation and high pressure tend to occur near vertical currents, but that neither phenomenon is cospatial with current maxima. In contrast with the conclusion of other authors, we argue that these observations do not support a current-interruption model for flares, unless the relevant currents are primarily horizontal. The magnetic morphology and temporal evolution of these flares suggest that an erupting filament model may be relevant, but this model does not explicitly predict the relationship between precipitation, high pressure, and vertical currents.

  13. TRACE and SVST Observations of an Active-Region Filament

    NASA Astrophysics Data System (ADS)

    van Ballegooijen, A. A.; Deluca, E. E.

    1999-05-01

    In June 1998 the Transition Region and Coronal Explorer (TRACE) observed filaments and prominences in coordination with various ground-based solar observatories, including the Swedish Vacuum Solar Telescope (SVST) on La Palma. Here we present results for an active-region filament observed on June 21-22. This horse-shoe shaped filament had a "barb" that reached down from the filament spine to the chomosphere below. We use high-resolution images obtained at the SVST on June 21 from 18:03 to 19:04 UT to study the fine structure and dynamics of plasmas in the barb and other parts of the filament. The data consist of narrowband Hα images taken with the Lockheed Tunable Filtergraph operating at a cadence of 20 s. We present Doppler maps derived from these images. The filament erupted six hours after the SVST observations. The eruption was observed with TRACE, which obtained images in Fe IX/X 171, Fe XII 195, Fe XV 284 and H I Lyalpha . At the start of the event, a thin bright loop appears high above the filament at the location of the barb. We interpret this feature as the outline of a magnetic "bubble" which forms as a result of kink instability in the magnetic field that supports the filament. The bright loop appears to be due to particle acceleration and impulsive heating along certain field lines on the periphery of this magnetic structure. A few minutes later, the dark filament threads turn into emission and move outward, exhibiting a helical structure. We discuss the magnetic structure of the barb and its possible role in the filament eruption.

  14. Breakout coronal mass ejections from solar active regions

    NASA Astrophysics Data System (ADS)

    DeVore, C. Richard; Lynch, Benjamin; MacNeice, Peter; Olson, Kevin; Antiochos, Spiro

    We are performing magnetohydrodynamic simulations of single bipolar active regions (ARs) embedded in the Sun's global background field and of pairs of ARs interacting with each other. The magnetic flux near the polarity inversion lines (PILs) of the ARs is subjected to twisting footpoint displacements that introduce strong magnetic shear between the two polarities and gradually inflate the coronal volume occupied by the AR fields. If the initially current-free coronal field contains a magnetic null, then it is vulnerable to eruptions triggered by magnetic breakout, which reconnects aside the previously restraining field lines overhead. The sheared core flux promptly expands outward at the Alfven speed, opening the magnetic field in the vicinity of the PIL. Flare reconnection below the ejecta, across the vertical current sheet thus established, thereafter reforms the magnetic-null configuration above the AR. This reformation sets the stage for subsequent homologous episodes of breakout reconnection and eruption, if the energizing footpoint motions are sustained. The magnetic flux and energy of an isolated AR, relative to those of the background field, determine whether the eruption is confined or ejective, as the sheared flux either comes to rest in the corona or escapes the Sun to interplanetary space, respectively. In the latter case, the field lines accompanying the coronal mass ejection can comprise a weakly twisted "magnetic bottle" as readily as a strongly twisted flux rope, both of which are observed routinely in situ. The latest developments in this research will be reported. In particular, we will emphasize the observational signatures inferred from the simulations that could be sought in STEREO data, such as multiple three-dimensional views, EUV brightenings at reconnection sites, and coronal dimmings in regions of strong expansion. Our research is sponsored by NASA and ONR.

  15. Generation of biologically active endostatin fragments from human collagen XVIII by distinct matrix metalloproteases

    SciTech Connect

    Heljasvaara, Ritva; Nyberg, Pia; Luostarinen, Jani; Parikka, Mataleena; Heikkilae, Pia; Rehn, Marko; Sorsa, Timo; Salo, Tuula; Pihlajaniemi, Taina . E-mail: taina.pihlajaniemi@oulu.fi

    2005-07-15

    Endostatin, a potent inhibitor of endothelial cell proliferation, migration, angiogenesis and tumor growth, is proteolytically cleaved from the C-terminal noncollagenous NC1 domain of type XVIII collagen. We investigated the endostatin formation from human collagen XVIII by several MMPs in vitro. The generation of endostatin fragments differing in molecular size (24-30 kDa) and in N-terminal sequences was identified in the cases of MMP-3, -7, -9, -13 and -20. The cleavage sites were located in the protease-sensitive hinge region between the trimerization and endostatin domains of NC1. MMP-1, -2, -8 and -12 did not show any significant activity against the C-terminus of collagen XVIII. The anti-proliferative effect of the 20-kDa endostatin, three longer endostatin-containing fragments generated in vitro by distinct MMPs and the entire NC1 domain, on bFGF-stimulated human umbilical vein endothelial cells was established. The anti-migratory potential of some of these fragments was also studied. In addition, production of endostatin fragments between 24-30 kDa by human hepatoblastoma cells was shown to be due to MMP action on type XVIII collagen. Our results indicate that certain, especially cancer-related, MMP family members can generate biologically active endostatin-containing polypeptides from collagen XVIII and thus, by releasing endostatin fragments, may participate in the inhibition of endothelial cell proliferation, migration and angiogenesis.

  16. Mental Arithmetic Activates Analogic Representations of Internally Generated Sums

    ERIC Educational Resources Information Center

    Kallai, Arava Y.; Schunn, Christian D.; Fiez, Julie A.

    2012-01-01

    The internal representation of numbers generated during calculation has received little attention. Much of the mathematics learning literature focuses on symbolic retrieval of math facts; in contrast, we critically test the hypothesis that internally generated numbers are represented analogically, using an approximate number system. In an fMRI…

  17. Activating Generative Learning in Organizations through Optimizing Relational Strategies

    ERIC Educational Resources Information Center

    Park, Mary Kay

    2010-01-01

    Using a grounded theory method, this dissertation seeks to discover how relationships impact organizational generative learning. An organization is a socially constructed reality and organizational learning is situated in the process of co-participation. To discover the link between relationships and generative learning this study considers the…

  18. 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

  19. Generation of ELF and ULF electromagnetic waves by modulated heating of the ionospheric F2 region

    NASA Astrophysics Data System (ADS)

    Eliasson, B.; Chang, C.-L.; Papadopoulos, K.

    2012-10-01

    We present a theoretical and numerical study of the generation of extremely low frequency (ELF) and ultra-low frequency (ULF) waves by the modulation of the electron pressure at the F2-region with an intense high-frequency electromagnetic wave. The study is based on a cold plasma Hall-MHD model, including electron-neutral and ion-neutral collisions, which governs the dynamics of magnetostatic waves and their propagation through the ionospheric layers. Magnetosonic waves generated in the F2 region are propagating isotropically and are channeled in the ionospheric waveguide, while shear Alfvén waves are propagating along the magnetic field. To penetrate the ionosphere from the F2 peak at 300 km to the ground, the magnetostatic waves first propagate as magnetosonic or shear Alfvén waves that encounter a diffusive layer from about 150 km to 120 km where the Pedersen conductivity dominates, and then as helicon (whistler-like) mode waves from about 120 km to 80 km where the ions are collisionally glued to the neutrals and the Hall conductivity dominates. By performing numerical simulations and studying the dispersive properties of the wave modes, we investigate the dynamics and penetration of ELF/ULF waves through the ionospheric layers to the ground and along the geomagnetic field lines to the magnetosphere. Realistic profiles of the ionospheric profiles of conductivity and density are used, together with different configurations of the geomagnetic field, relevant for both the high, mid and equatorial latitudes. Some of the results are compared with recent HAARP experiments.

  20. 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.

  1. Unravelling the competing influence of regional uplift and active normal faulting in SW Calabria, Italy

    NASA Astrophysics Data System (ADS)

    Whittaker, Alex; Roda Boluda, Duna; Boulton, Sarah; Erhardt, Sebastian

    2015-04-01

    The Neogene geological and geomorphological evolution of Southern Italy is complex and is fundamentally controlled by the subduction of the Ionian slab along the Apennine belt from the Calabrian Arc, and back-arc extension driven by trench rollback. In the area of Calabria and the Straits of Messina the presence of (i) uplifted, deformed and dissected basin sediments and marine terraces, ranging in age from the early to mid-Pleistocene and (ii) seismicity associated with NE-SW normal faults that have well-developed footwall topography and triangular facets have led workers to suggest that both significant regional uplift and extensional faulting in SW Calabria have played a role in generating relief in the area since the mid Pleistocene. However, there is considerable uncertainty in the rates of total surface uplift relative to sea level in both time and space, and the relative partitioning of this uplift between a mantle-driven regional signal, potentially related to a slab tear, and the active extensional structures. Additionally, despite the widespread recognition of normal faults in Calabria to which historical earthquakes are often linked, there is much less agreement on (i) which ones are active and for what length of time; (ii) how the faults interact; and (iii) what their throw and throw rates are. In particular, the ability to resolve both regional uplift and normal faulting in SW Calabria is essential in order to fully understand the tectonic history of the region, while an understanding of location and slip rate of active faults, in an area where the population numbers more than two million people, is essential to assess regional seismic hazards. Here we address these important questions using a combination of tectonic geomorphology and structural geology. We critically examine existing constraints on the rates and distribution of active normal faulting and regional uplift in the area, and we derive new constraints on the along-strike variation in throw

  2. FIP Bias Evolution in a Decaying Active Region

    NASA Astrophysics Data System (ADS)

    Baker, D.; Brooks, D. H.; Démoulin, P.; Yardley, S. L.; van Driel-Gesztelyi, L.; Long, D. M.; Green, L. M.

    2015-04-01

    Solar coronal plasma composition is typically characterized by first ionization potential (FIP) bias. Using spectra obtained by Hinode’s EUV Imaging Spectrometer instrument, we present a series of large-scale, spatially resolved composition maps of active region (AR)11389. The composition maps show how FIP bias evolves within the decaying AR during the period 2012 January 4-6. Globally, FIP bias decreases throughout the AR. We analyzed areas of significant plasma composition changes within the decaying AR and found that small-scale evolution in the photospheric magnetic field is closely linked to the FIP bias evolution observed in the corona. During the AR’s decay phase, small bipoles emerging within supergranular cells reconnect with the pre-existing AR field, creating a pathway along which photospheric and coronal plasmas can mix. The mixing timescales are shorter than those of plasma enrichment processes. Eruptive activity also results in shifting the FIP bias closer to photospheric in the affected areas. Finally, the FIP bias still remains dominantly coronal only in a part of the AR’s high-flux density core. We conclude that in the decay phase of an AR’s lifetime, the FIP bias is becoming increasingly modulated by episodes of small-scale flux emergence, i.e., decreasing the AR’s overall FIP bias. Our results show that magnetic field evolution plays an important role in compositional changes during AR development, revealing a more complex relationship than expected from previous well-known Skylab results showing that FIP bias increases almost linearly with age in young ARs.

  3. SVBR-100 module-type fast reactor of the IV generation for regional power industry

    NASA Astrophysics Data System (ADS)

    Zrodnikov, A. V.; Toshinsky, G. I.; Komlev, O. G.; Stepanov, V. S.; Klimov, N. N.

    2011-08-01

    In the report the following is presented: basic conceptual provisions of the innovative nuclear power technology (NPT) based on modular fast reactors (FR) SVBR-100, summarized results of calculations of the reactor, analysis of the opportunities of multi-purpose application of such reactor facilities (RF) including export potentials with due account of nonproliferation requirements. The most important features of the proposed NPT analyzed in the report are as follows: (1) integral (monoblock) arrangement of the primary circuit equipment with entire elimination of the primary circuit pipelines and valves that considerably reduces the construction and assembly works period and coupling with high boiling point of lead-bismuth coolant (LBC) deterministically eliminates accidents of the LOCA type, (2) option for 100 MWe power and dimensions of the reactor provide: on the one hand, an opportunity to transport the reactor monoblock in factory-readiness by railway as well as other kinds of transport, on the other hand, core breeding ratio (CBR) exceeds 1 while MOX-fuel is used. The preferable area of application of RF SVBR-100 is regional and small power requiring power-units of electric power in a range of (100-600) MW, which could be used for cogeneration-based district heating while locating them nearby cities as well as for generation of electric power in a mode of load tracking in the regions with low network systems.

  4. LPV control for the full region operation of a wind turbine integrated with synchronous generator.

    PubMed

    Cao, Guoyan; Grigoriadis, Karolos M; Nyanteh, Yaw D

    2015-01-01

    Wind turbine conversion systems require feedback control to achieve reliable wind turbine operation and stable current supply. A robust linear parameter varying (LPV) controller is proposed to reduce the structural loads and improve the power extraction of a horizontal axis wind turbine operating in both the partial load and the full load regions. The LPV model is derived from the wind turbine state space models extracted by FAST (fatigue, aerodynamics, structural, and turbulence) code linearization at different operating points. In order to assure a smooth transition between the two regions, appropriate frequency-dependent varying scaling parametric weighting functions are designed in the LPV control structure. The solution of a set of linear matrix inequalities (LMIs) leads to the LPV controller. A synchronous generator model is connected with the closed LPV control loop for examining the electrical subsystem performance obtained by an inner speed control loop. Simulation results of a 1.5 MW horizontal axis wind turbine model on the FAST platform illustrates the benefit of the LPV control and demonstrates the advantages of this proposed LPV controller, when compared with a traditional gain scheduling PI control and prior LPV control configurations. Enhanced structural load mitigation, improved power extraction, and good current performance were obtained from the proposed LPV control. PMID:25884036

  5. LPV Control for the Full Region Operation of a Wind Turbine Integrated with Synchronous Generator

    PubMed Central

    Grigoriadis, Karolos M.; Nyanteh, Yaw D.

    2015-01-01

    Wind turbine conversion systems require feedback control to achieve reliable wind turbine operation and stable current supply. A robust linear parameter varying (LPV) controller is proposed to reduce the structural loads and improve the power extraction of a horizontal axis wind turbine operating in both the partial load and the full load regions. The LPV model is derived from the wind turbine state space models extracted by FAST (fatigue, aerodynamics, structural, and turbulence) code linearization at different operating points. In order to assure a smooth transition between the two regions, appropriate frequency-dependent varying scaling parametric weighting functions are designed in the LPV control structure. The solution of a set of linear matrix inequalities (LMIs) leads to the LPV controller. A synchronous generator model is connected with the closed LPV control loop for examining the electrical subsystem performance obtained by an inner speed control loop. Simulation results of a 1.5 MW horizontal axis wind turbine model on the FAST platform illustrates the benefit of the LPV control and demonstrates the advantages of this proposed LPV controller, when compared with a traditional gain scheduling PI control and prior LPV control configurations. Enhanced structural load mitigation, improved power extraction, and good current performance were obtained from the proposed LPV control. PMID:25884036

  6. REGION 4-SESD TRAINING ACTIVITIES: OCTOBER 2005 – SEPTEMBER 2006

    EPA Science Inventory

    Each year, the Science and Ecosytem Support Division (SESD) provides training and technical assistance to hundreds of students in EPA Region 4. Training courses are presented to Region 4 employees, Region 4 States, Indian Tribes, Universities and other Federal Agencies in the are...

  7. Emotion at Work: A Contribution to Third-Generation Cultural-Historical Activity Theory

    ERIC Educational Resources Information Center

    Roth, Wolff-Michael

    2007-01-01

    Second-generation cultural-historical activity theory, which drew its inspiration from Leont'ev's work, constituted an advance over Vygotsky's first-generation theory by explicitly articulating the dialectical relation between individual and collective. As part of an effort to develop third-generation-historical activity theory, I propose in this…

  8. Optical Properties of Active Regions in Terahertz Quantum Cascade Lasers

    NASA Astrophysics Data System (ADS)

    Dyksik, M.; Motyka, M.; Rudno-Rudziński, W.; Sęk, G.; Misiewicz, J.; Pucicki, D.; Kosiel, K.; Sankowska, I.; Kubacka-Traczyk, J.; Bugajski, M.

    2016-07-01

    In this work, AlGaAs/GaAs superlattice, with layers' sequence and compositions imitating the active and injector regions of a quantum cascade laser designed for emission in the terahertz spectral range, was investigated. Three independent absorption-like optical spectroscopy techniques were employed in order to study the band structure of the minibands formed within the conduction band. Photoreflectance measurements provided information about interband transitions in the investigated system. Common transmission spectra revealed, in the target range of intraband transitions, mainly a number of lines associated with the phonon-related processes, including two-phonon absorption. In contrast, differential transmittance realized by means of Fourier-transform spectroscopy was utilized to probe the confined states of the conduction band. The obtained energy separation between the second and third confined electron levels, expected to be predominantly contributing to the lasing, was found to be ~9 meV. The optical spectroscopy measurements were supported by numerical calculations performed in the effective mass approximation and XRD measurements for layers' width verification. The calculated energy spacings are in a good agreement with the experimental values.

  9. Activation of cutaneous immune responses in complex regional pain syndrome

    PubMed Central

    Birklein, Frank; Drummond, Peter D.; Li, Wenwu; Schlereth, Tanja; Albrecht, Nahid; Finch, Philip M.; Dawson, Linda F.; Clark, J. David; Kingery, Wade S.

    2014-01-01

    The pathogenesis of complex regional pain syndrome (CRPS) is unresolved, but TNF-α and IL-6 are elevated in experimental skin blister fluid from CRPS affected limbs, as is tryptase, a marker for mast cells. In the rat fracture model of CRPS exaggerated sensory and sympathetic neural signaling stimulate keratinocyte and mast cell proliferation, causing the local production of high levels of inflammatory cytokines leading to pain behavior. The current investigation used CRPS patient skin biopsies to determine whether keratinocyte and mast cell proliferation occur in CRPS skin and to identify the cellular source of the up-regulated TNF-α, IL-6, and tryptase observed in CRPS experimental skin blister fluid. Skin biopsies were collected from the affected skin and the contralateral mirror site in 55 CRPS patients and the biopsy sections were immunostained for keratinocyte, cell proliferation, mast cell markers, TNF-α, and IL-6. In early CRPS keratinocytes were activated in the affected skin, resulting in proliferation, epidermal thickening, and up-regulated TNF-α and IL-6 expression. In chronic CRPS there was reduced keratinocyte proliferation with epidermal thinning in the affected skin. Acute CRPS patients also had increased mast cell accumulation in the affected skin, but there was no increase in mast cell numbers in chronic CRPS. PMID:24462502

  10. Active region emission measure distributions and implications for nanoflare heating

    SciTech Connect

    Cargill, P. J.

    2014-03-20

    The temperature dependence of the emission measure (EM) in the core of active regions coronal loops is an important diagnostic of heating processes. Observations indicate that EM(T) ∼ T{sup a} below approximately 4 MK, with 2 < a < 5. Zero-dimensional hydrodynamic simulations of nanoflare trains are used to demonstrate the dependence of a on the time between individual nanoflares (T{sub N} ) and the distribution of nanoflare energies. If T{sub N} is greater than a few thousand seconds, a < 3. For smaller values, trains of equally spaced nanoflares cannot account for the observed range of a if the distribution of nanoflare energies is either constant, randomly distributed, or a power law. Power law distributions where there is a delay between consecutive nanoflares proportional to the energy of the second nanoflare do lead to the observed range of a. However, T{sub N} must then be of the order of hundreds to no more than a few thousand seconds. If a nanoflare leads to the relaxation of a stressed coronal field to a near-potential state, the time taken to build up the required magnetic energy is thus too long to account for the EM measurements. Instead, it is suggested that a nanoflare involves the relaxation from one stressed coronal state to another, dissipating only a small fraction of the available magnetic energy. A consequence is that nanoflare energies may be smaller than previously envisioned.

  11. Static and Impulsive Models of Solar Active Regions

    NASA Technical Reports Server (NTRS)

    Patsourakos, S.; Klimchuk, James A.

    2008-01-01

    The physical modeling of active regions (ARs) and of the global coronal is receiving increasing interest lately. Recent attempts to model ARs using static equilibrium models were quite successful in reproducing AR images of hot soft X-ray (SXR) loops. They however failed to predict the bright EUV warm loops permeating ARs: the synthetic images were dominated by intense footpoint emission. We demonstrate that this failure is due to the very weak dependence of loop temperature on loop length which cannot simultaneously account for both hot and warm loops in the same AR. We then consider time-dependent AR models based on nanoflare heating. We demonstrate that such models can simultaneously reproduce EUV and SXR loops in ARs. Moreover, they predict radial intensity variations consistent with the localized core and extended emissions in SXR and EUV AR observations respectively. We finally show how the AR morphology can be used as a gauge of the properties (duration, energy, spatial dependence, repetition time) of the impulsive heating.

  12. Plasma Composition in a Sigmoidal Anemone Active Region

    NASA Astrophysics Data System (ADS)

    Baker, D.; Brooks, D. H.; Démoulin, P.; van Driel-Gesztelyi, L.; Green, L. M.; Steed, K.; Carlyle, J.

    2013-11-01

    Using spectra obtained by the EUV Imaging Spectrometer (EIS) instrument onboard Hinode, we present a detailed spatially resolved abundance map of an active region (AR)-coronal hole (CH) complex that covers an area of 359'' × 485''. The abundance map provides first ionization potential (FIP) bias levels in various coronal structures within the large EIS field of view. Overall, FIP bias in the small, relatively young AR is 2-3. This modest FIP bias is a consequence of the age of the AR, its weak heating, and its partial reconnection with the surrounding CH. Plasma with a coronal composition is concentrated at AR loop footpoints, close to where fractionation is believed to take place in the chromosphere. In the AR, we found a moderate positive correlation of FIP bias with nonthermal velocity and magnetic flux density, both of which are also strongest at the AR loop footpoints. Pathways of slightly enhanced FIP bias are traced along some of the loops connecting opposite polarities within the AR. We interpret the traces of enhanced FIP bias along these loops to be the beginning of fractionated plasma mixing in the loops. Low FIP bias in a sigmoidal channel above the AR's main polarity inversion line, where ongoing flux cancellation is taking place, provides new evidence of a bald patch magnetic topology of a sigmoid/flux rope configuration.

  13. Plasma composition in a sigmoidal anemone active region

    SciTech Connect

    Baker, D.; Van Driel-Gesztelyi, L.; Green, L. M.; Carlyle, J.; Brooks, D. H.; Démoulin, P.; Steed, K.

    2013-11-20

    Using spectra obtained by the EUV Imaging Spectrometer (EIS) instrument onboard Hinode, we present a detailed spatially resolved abundance map of an active region (AR)-coronal hole (CH) complex that covers an area of 359'' × 485''. The abundance map provides first ionization potential (FIP) bias levels in various coronal structures within the large EIS field of view. Overall, FIP bias in the small, relatively young AR is 2-3. This modest FIP bias is a consequence of the age of the AR, its weak heating, and its partial reconnection with the surrounding CH. Plasma with a coronal composition is concentrated at AR loop footpoints, close to where fractionation is believed to take place in the chromosphere. In the AR, we found a moderate positive correlation of FIP bias with nonthermal velocity and magnetic flux density, both of which are also strongest at the AR loop footpoints. Pathways of slightly enhanced FIP bias are traced along some of the loops connecting opposite polarities within the AR. We interpret the traces of enhanced FIP bias along these loops to be the beginning of fractionated plasma mixing in the loops. Low FIP bias in a sigmoidal channel above the AR's main polarity inversion line, where ongoing flux cancellation is taking place, provides new evidence of a bald patch magnetic topology of a sigmoid/flux rope configuration.

  14. SIMULATION OF THE FORMATION OF A SOLAR ACTIVE REGION

    SciTech Connect

    Cheung, M. C. M.; Title, A. M.; Rempel, M.; Schuessler, M.

    2010-09-01

    We present a radiative magnetohydrodynamics simulation of the formation of an active region (AR) on the solar surface. The simulation models the rise of a buoyant magnetic flux bundle from a depth of 7.5 Mm in the convection zone up into the solar photosphere. The rise of the magnetic plasma in the convection zone is accompanied by predominantly horizontal expansion. Such an expansion leads to a scaling relation between the plasma density and the magnetic field strength such that B {proportional_to} rhov{sup 1/2}. The emergence of magnetic flux into the photosphere appears as a complex magnetic pattern, which results from the interaction of the rising magnetic field with the turbulent convective flows. Small-scale magnetic elements at the surface first appear, followed by their gradual coalescence into larger magnetic concentrations, which eventually results in the formation of a pair of opposite polarity spots. Although the mean flow pattern in the vicinity of the developing spots is directed radially outward, correlations between the magnetic field and velocity field fluctuations allow the spots to accumulate flux. Such correlations result from the Lorentz-force-driven, counterstreaming motion of opposite polarity fragments. The formation of the simulated AR is accompanied by transient light bridges between umbrae and umbral dots. Together with recent sunspot modeling, this work highlights the common magnetoconvective origin of umbral dots, light bridges, and penumbral filaments.

  15. Theoretical model for calculation of helicity in solar active regions

    NASA Astrophysics Data System (ADS)

    Chatterjee, P.

    We (Choudhuri, Chatterjee and Nandy, 2005) calculate helicities of solar active regions based on the idea of Choudhuri (2003) that poloidal flux lines get wrapped around a toroidal flux tube rising through the convection zone, thereby giving rise to the helicity. Rough estimates based on this idea compare favourably with the observed magnitude of helicity. We use our solar dynamo model based on the Babcock--Leighton α-effect to study how helicity varies with latitude and time. At the time of solar maximum, our theoretical model gives negative helicity in the northern hemisphere and positive helicity in the south, in accordance with observed hemispheric trends. However, we find that, during a short interval at the beginning of a cycle, helicities tend to be opposite of the preferred hemispheric trends. Next we (Chatterjee, Choudhuri and Petrovay 2006) use the above idea along with the sunspot decay model of Petrovay and Moreno-Insertis, (1997) to estimate the distribution of helicity inside a flux tube as it keeps collecting more azimuthal flux during its rise through the convection zone and as turbulent diffusion keeps acting on it. By varying parameters over reasonable ranges in our simple 1-d model, we find that the azimuthal flux penetrates the flux tube to some extent instead of being confined to a narrow sheath outside.

  16. Static and Impulsive Models of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Patsourakos, S.; Klimchuk, J. A.

    2008-12-01

    The physical modeling of active regions (ARs) and of the global corona is receiving increasing interest lately. Recent attempts to model ARs using static equilibrium models were quite successful in reproducing AR images of hot soft X-ray (SXR) loops. They however failed to predict the bright extreme-ultraviolet (EUV) warm loops permeating ARs: the synthetic images were dominated by intense footpoint emission. We demonstrate that this failure is due to the very weak dependence of loop temperature on loop length which cannot simultaneously account for both hot and warm loops in the same AR. We then consider time-dependent AR models based on nanoflare heating. We demonstrate that such models can simultaneously reproduce EUV and SXR loops in ARs. Moreover, they predict radial intensity variations consistent with the localized core and extended emissions in SXR and EUV AR observations, respectively. We finally show how the AR morphology can be used as a gauge of the properties (duration, energy, spatial dependence, and repetition time) of the impulsive heating.

  17. Characterization of regions within the N-terminal 6-kilodalton domain of phytochrome A that modulate its biological activity.

    PubMed Central

    Jordan, E T; Marita, J M; Clough, R C; Vierstra, R D

    1997-01-01

    Phytochrome A (phyA) is a red/far-red (FR) light photoreceptor responsible for initiating numerous light-mediated plant growth and developmental responses, especially in FR light-enriched environments. We previously showed that the first 70 amino acids of the polypeptide contain at least two regions with potentially opposite functions (E.T. Jordan, J.R. Cherry, J.M. Walker, R.D. Vierstra [1996] Plant J 9: 243-257). One region is required for activity and correct apoprotein/chromophore interactions, whereas the second appears to regulate phytochrome activity. We have further resolved these functional regions by analysis of N-terminal deletion and alanine-scanning mutants of oat (Avena sativa) phyA in transgenic tobacco (Nicotiana tabacum). The results indicate that the region involved in chromophore/apoprotein interactions contains two separate segments (residues 25-33 and 50-62) also required for biological activity. The region that regulates phyA activity requires only five adjacent serines (Sers) (residues 8-12). Removal or alteration of these Sers generates a photoreceptor that increases the sensitivity of transgenic seedlings to red and FR light more than intact phyA. Taken together, these data identify three distinct regions in the N-terminal domain necessary for photoreceptor activity, and further define the Ser-rich region as an important site for phyA regulation. PMID:9342873

  18. Active folded structures of the Western Caucasus (Sochi region)

    NASA Astrophysics Data System (ADS)

    Trikhunkov, Yaroslav; Zelenin, Egor

    2014-05-01

    The Western Caucasus as a margin segment of folded system of the Greater Caucasus was formed at the periphery of collision interaction of the Scythian Plate and the Transcaucasian Massif. The estimated age of the primary folded deformations of the initial surface of that territory ranges from the late Eocene to late Neogene. We have obtained new data on modern folded deformations of the anticlinal ridges, which prevail in Sochi region in the southern macroslope of the mountain system. Very similar Alek, Galitsinsky, Akhun, Nikolaevsky anticlinal ridges are uplifting in the main Caucasus direction (NW - SE) and are crossed by narrow antecedent river valleys. These ridges stand out contrasting to sinclinal depressions, where fluviatile accumulation prevails. At the intersection of the Mzymta river and the Galitsinsky anticlinal ridge a narrow Akhshtyr canyon with steep, 150 meters high slopes were formed. Downstream in the neighboring Akhshtyr synclinal depression the valley expands. Here the floodplain and two levels of terraces with the height of 20 - 30 and 50 - 60 m correspondingly were formed. The age of the first terrace was defined by archeologic data of V. Shchelinsky (2007) and by correlation with marine Black Sea Late Karangat terrace as a 135 - 90 ka (Eemian interglacial). The second terrace is apparently older and dates back to Middle Pleistocene. The field research and analysis of the elevations by ASTER GDEM allowed us to trace both terraces in the southern structural slope of the Galitsinsky ridge above the canyon, adjacent to the Akhshtyr depression, at the heights 70 and 110 m correspondingly. Alluvial deposits in outcrops of lower terrace (elongated pebbles, which look like modern alluvium of the Mzymta) were traced on the surface of the slope. Thereby, described fragments of the Mzymta terraces were uplifted above the level of the corresponding terraces in the synclinal depression as a result of dislocation on the slope of the actively uplifting

  19. Transcription activation at class II CRP-dependent promoters: the role of different activating regions.

    PubMed Central

    Rhodius, V A; West, D M; Webster, C L; Busby, S J; Savery, N J

    1997-01-01

    Transcription activation by the Escherichia coli cyclic AMP receptor protein (CRP) at Class II promoters is dependent on direct interactions between two surface-exposed activating regions (AR1 and AR2) and two contact sites in RNA polymerase. The effects on transcription activation of disrupting either AR1 or AR2 have been measured at different Class II promoters. AR2 but not AR1 is essential for activation at all the Class II promoters that were tested. The effects of single positive control substitutions in AR1 and AR2 vary from one promoter to another: the effects of the different substitutions are contingent on the -35 hexamer sequence. Abortive initiation assays have been used to quantify the effects of positive control substitutions in each activating region on the kinetics of transcription initiation at the Class II CRP- dependent promoter pmelRcon. At this promoter, the HL159 substitution in AR1 results in a defect in the initial binding of RNA polymerase whilst the KE101 substitution in AR2 reduces the rate of isomerization from the closed to the open complex. PMID:9016561

  20. 20 CFR 667.262 - Are employment generating activities, or similar activities, allowable under WIA title I?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... generating activities, or similar activities, allowable under WIA title I? (a) Under WIA section 181(e), WIA... associations (such as chambers of commerce); joint labor management committees, labor associations, and.... 181(e).)...

  1. Observation and Modelling of Micropore Formation in Active Network Regions

    NASA Astrophysics Data System (ADS)

    Berger, T. E.; Löfdahl, M. G.; Bercik, D. J.

    2002-06-01

    We present phase-diversity corrected G-band 4305 Å and 4364 Å continuum image time series showing the formation of a micropore in a small active region near disk center. The data were acquired at the Swedish Vacuum Solar Telescope on La Palma in June of 1997 and post-processed using the Phase Diverse Speckle (PDS) algorithm to produce diffraction limited images throughout the majority of both time series. The micropore dataset comprises a 29x29 Mm field of view and spans 5.1 hours with a 38 second cadence. The micropore forms in a strong sink area that can be seen to ``collect" many G-band bright points over the first 2 hours of the observation. During this time there is an occasional darkening at the sink point that may be the first unstable phase of the micropore formation. Once a stable dark pore forms in the flowfield, it grows to a maximum diameter of 1.2 Mm in approximately 1.9 hours. The pore persists for another 35 minutes before apparently being broken up by the intergranular flowfield. The total ``lifetime" of the stable pore phase is 2.5 hours. A separate nearby micropore of 1.5 Mm maximum diameter exists for the entire 5.2 hour data span. We show G-band and continuum movies of the micropore formation, correlation tracking flowfield analyses, G-band bright point tracking results, and area versus time plots for the micropore formation lifetime. The observational data are compared with fully compressible 3D MHD numerical simulations which show the development of a similar micropore structure within the computational domain. This research was supported by NASA SR&T grant NASW-98008, The Royal Swedish Academy of Sciences, NSF and NASA funding at Michigan State University, and Lockheed Martin IRAD funding.

  2. ASYMMETRY OF HELICITY INJECTION FLUX IN EMERGING ACTIVE REGIONS

    SciTech Connect

    Tian Lirong; Alexander, David

    2009-04-20

    Observational and modeling results indicate that typically the leading magnetic field of bipolar active regions (ARs) is often spatially more compact, while more dispersed and fragmented in following polarity. In this paper, we address the origin of this morphological asymmetry, which is not well understood. Although it may be assumed that, in an emerging {omega}-shaped flux tube, those portions of the flux tube in which the magnetic field has a higher twist may maintain its coherence more readily, this has not been tested observationally. To assess this possibility, it is important to characterize the nature of the fragmentation and asymmetry in solar ARs and this provides the motivation for this paper. We separately calculate the distribution of the helicity flux injected in the leading and following polarities of 15 emerging bipolar ARs, using the Michelson Doppler Image 96 minute line-of-sight magnetograms and a local correlation tracking technique. We find from this statistical study that the leading (compact) polarity injects several times more helicity flux than the following (fragmented) one (typically 3-10 times). This result suggests that the leading polarity of the {omega}-shaped flux tube possesses a much larger amount of twist than the following field prior to emergence. We argue that the helicity asymmetry between the leading and following magnetic field for the ARs studied here results in the observed magnetic field asymmetry of the two polarities due to an imbalance in the magnetic tension of the emerging flux tube. We suggest that the observed imbalance in the helicity distribution results from a difference in the speed of emergence between the leading and following legs of an inclined {omega}-shaped flux tube. In addition, there is also the effect of magnetic flux imbalance between the two polarities with the fragmented following polarity displaying spatial fluctuation in both the magnitude and sign of helicity measured.

  3. Identifying the Main Driver of Active Region Outflows

    NASA Astrophysics Data System (ADS)

    Baker, D.; van Driel-Gesztelyi, L.; Mandrini, C. H.; Démoulin, P.; Murray, M. J.

    2012-08-01

    Hinode's EUV Imaging Spectrometer (EIS) has discovered ubiquitous outflows of a few to 50 km s-1 from active regions (ARs). The characteristics of these outflows are very curious in that they are most prominent at the AR boundary and appear over monopolar magnetic areas. They are linked to strong non-thermal line broadening and are stronger in hotter EUV lines. The outflows persist for at least several days. Whereas red-shifted down flows observed in AR closed loops are well understood, to date there is no general consensus for the mechanism(s) driving blue-shifted AR-related outflows. We use Hinode EIS and X-Ray Telescope observations of AR 10942 coupled with magnetic modeling to demonstrate for the first time that the outflows originate from specific locations of the magnetic topology where field lines display strong gradients of magnetic connectivity, namely quasi-separatrix layers (QSLs), or in the limit of infinitely thin QSLs, separatrices. The strongest AR outflows were found to be in the vicinity of QSL sections located over areas of strong magnetic field. We argue that magnetic reconnection at QSLs, separating closed field lines of the AR and either large-scale externally connected or ‘open’ field lines, is a viable mechanism for driving AR outflows which are potentially sources of the slow solar wind. In fact, magnetic reconnection along QSLs (including separatricies) is the first theory to explain the most puzzling characteristics of the outflows, namely their occurrence over monopolar areas at the periphery of ARs and their longevity.

  4. ABRUPT LONGITUDINAL MAGNETIC FIELD CHANGES IN FLARING ACTIVE REGIONS

    SciTech Connect

    Petrie, G. J. D.; Sudol, J. J.

    2010-12-01

    We characterize the changes in the longitudinal photospheric magnetic field during 38 X-class and 39 M-class flares within 65{sup 0} of disk center using 1 minute GONG magnetograms. In all 77 cases, we identify at least one site in the flaring active region where clear, permanent, stepwise field changes occurred. The median duration of the field changes was about 15 minutes and was approximately equal for X-class and for M-class flares. The absolute values of the field changes ranged from the detection limit of {approx}10 G to as high as {approx}450 G in two exceptional cases. The median value was 69 G. Field changes were significantly stronger for X-class than for M-class flares and for limb flares than for disk-center flares. Longitudinal field changes less than 100 G tended to decrease longitudinal field strengths, both close to disk center and close to the limb, while field changes greater than 100 G showed no such pattern. Likewise, longitudinal flux strengths tended to decrease during flares. Flux changes, particularly net flux changes near disk center, correlated better than local field changes with GOES peak X-ray flux. The strongest longitudinal field and flux changes occurred in flares observed close to the limb. We estimate the change of Lorentz force associated with each flare and find that this is large enough in some cases to power seismic waves. We find that longitudinal field decreases would likely outnumber increases at all parts of the solar disk within 65{sup 0} of disk center, as in our observations, if photospheric field tilts increase during flares as predicted by Hudson et al.

  5. Spectroscopic Observations of Fe XVIII in Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Teriaca, Luca; Warren, Harry P.; Curdt, Werner

    2012-08-01

    The large uncertainties associated with measuring the amount of high temperature emission in solar active regions (ARs) represents a significant impediment to making progress on the coronal heating problem. Most current observations at temperatures of 3 MK and above are taken with broadband soft X-ray instruments. Such measurements have proven difficult to interpret unambiguously. Here, we present the first spectroscopic observations of the Fe XVIII 974.86 Å emission line in an on-disk AR taken with the SUMER instrument on SOHO. Fe XVIII has a peak formation temperature of 7.1 MK and provides important constraints on the amount of impulsive heating in the corona. Detailed evaluation of the spectra and comparison of the SUMER data with soft X-ray images from the X-Ray Telescope on Hinode confirm that this line is unblended. We also compare the spectroscopic data with observations from the Atmospheric Imaging Assembly (AIA) 94 Å channel on the Solar Dynamics Observatory. The AIA 94 Å channel also contains Fe XVIII, but is blended with emission formed at lower temperatures. We find that it is possible to remove the contaminating blends and form relatively pure Fe XVIII images that are consistent with the spectroscopic observations from SUMER. The observed spectra also contain the Ca XIV 943.63 Å line that, although a factor 2-6 weaker than the Fe XVIII 974.86 Å line, allows us to probe the plasma around 3.5 MK. The observed ratio between the two lines indicates (isothermal approximation) that most of the plasma in the brighter Fe XVIII AR loops is at temperatures between 3.5 and 4 MK.

  6. MAGNETIC HELICITY AND ENERGY SPECTRA OF A SOLAR ACTIVE REGION

    SciTech Connect

    Zhang, Hongqi; Brandenburg, Axel; Sokoloff, D. D.

    2014-04-01

    We compute for the first time the magnetic helicity and energy spectra of the solar active region NOAA 11158 during 2011 February 11-15 at 20° southern heliographic latitude using observational photospheric vector magnetograms. We adopt the isotropic representation of the Fourier-transformed two-point correlation tensor of the magnetic field. The sign of the magnetic helicity turns out to be predominantly positive at all wavenumbers. This sign is consistent with what is theoretically expected for the southern hemisphere. The magnetic helicity normalized to its theoretical maximum value, here referred to as relative helicity, is around 4% and strongest at intermediate wavenumbers of k ≈ 0.4 Mm{sup –1}, corresponding to a scale of 2π/k ≈ 16 Mm. The same sign and a similar value are also found for the relative current helicity evaluated in real space based on the vertical components of magnetic field and current density. The modulus of the magnetic helicity spectrum shows a k {sup –11/3} power law at large wavenumbers, which implies a k {sup –5/3} spectrum for the modulus of the current helicity. A k {sup –5/3} spectrum is also obtained for the magnetic energy. The energy spectra evaluated separately from the horizontal and vertical fields agree for wavenumbers below 3 Mm{sup –1}, corresponding to scales above 2 Mm. This gives some justification to our assumption of isotropy and places limits resulting from possible instrumental artifacts at small scales.

  7. Synthetic Training Data Generation for Activity Monitoring and Behavior Analysis

    NASA Astrophysics Data System (ADS)

    Monekosso, Dorothy; Remagnino, Paolo

    This paper describes a data generator that produces synthetic data to simulate observations from an array of environment monitoring sensors. The overall goal of our work is to monitor the well-being of one occupant in a home. Sensors are embedded in a smart home to unobtrusively record environmental parameters. Based on the sensor observations, behavior analysis and modeling are performed. However behavior analysis and modeling require large data sets to be collected over long periods of time to achieve the level of accuracy expected. A data generator - was developed based on initial data i.e. data collected over periods lasting weeks to facilitate concurrent data collection and development of algorithms. The data generator is based on statistical inference techniques. Variation is introduced into the data using perturbation models.

  8. ON THE ROLE OF ROTATING SUNSPOTS IN THE ACTIVITY OF SOLAR ACTIVE REGION NOAA 11158

    SciTech Connect

    Vemareddy, P.; Ambastha, A.; Maurya, R. A. E-mail: ambastha@prl.res.in

    2012-12-10

    We study the role of rotating sunspots in relation to the evolution of various physical parameters characterizing the non-potentiality of the active region (AR) NOAA 11158 and its eruptive events using the magnetic field data from the Helioseismic and Magnetic Imager (HMI) and multi-wavelength observations from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. From the evolutionary study of HMI intensity and AIA channels, it is observed that the AR consists of two major rotating sunspots, one connected to a flare-prone region and another with coronal mass ejection (CME). The constructed space-time intensity maps reveal that the sunspots exhibited peak rotation rates coinciding with the occurrence of major eruptive events. Further, temporal profiles of twist parameters, namely, average shear angle, {alpha}{sub av}, {alpha}{sub best}, derived from HMI vector magnetograms, and the rate of helicity injection, obtained from the horizontal flux motions of HMI line-of-sight magnetograms, correspond well with the rotational profile of the sunspot in the CME-prone region, giving predominant evidence of rotational motion causing magnetic non-potentiality. Moreover, the mean value of free energy from the virial theorem calculated at the photospheric level shows a clear step-down decrease at the onset time of the flares revealing unambiguous evidence of energy release intermittently that is stored by flux emergence and/or motions in pre-flare phases. Additionally, distribution of helicity injection is homogeneous in the CME-prone region while in the flare-prone region it is not and often changes sign. This study provides a clear picture that both proper and rotational motions of the observed fluxes played significant roles in enhancing the magnetic non-potentiality of the AR by injecting helicity, twisting the magnetic fields and thereby increasing the free energy, leading to favorable conditions for the observed transient activity.

  9. On transient events in the upper atmosphere generated away of thunderstorm regions

    NASA Astrophysics Data System (ADS)

    Morozenko, V.; Garipov, G.; Khrenov, B.; Klimov, P.; Panasyuk, M.; Sharakin, S.; Zotov, M.

    2011-12-01

    Experimental data on transient events in UV and Red-IR ranges obtained in the MSU missions "Unversitetsky-Tatiana" (wavelengths 300-400 nm) and "Unversitetsky-Tatiana-2" (wavelengths 300-400 nm and 600-800 nm), published by Garipov et al, in 2010 at COSPAR session http://www.cospar2010.org, at TEPA conference http://www.aragats.am/Conferences/tepa2010 and in 2011 by Sadovnichy et al, Solar System Research, 45, #1, 3-29 (2011); Vedenkin et al, JETP, v. 140, issue 3(9), 1-11 (2011) demonstrated existence of transients at large distances (up to thousands km) away of cloud thunderstorm regions. Those "remote" transients are short (1-5 msec) and are less luminous than the transients above thunderstorm regions. The ratio of Red-IR to UV photon numbers in those transients indicates high altitude of their origin (~70 km). Important observation facts are also: 1. a change of the exponent in transient distribution on luminosity Q ("-1" for photon numbers Q=1020 -1023 to "-2" for Q>1023), 2. a change of global distribution of transient with their luminosity (transients with Q>1023 are concentrated in equatorial range above continents, while transients with low luminosity are distributed more uniformly), 3. a phenomenon of transient sequences in one satellite orbit which is close to geomagnetic meridian. In the present paper phenomenological features of transients are explained in assumption that the observed transients have to be divided in two classes: 1. transients related to local, lower in the atmosphere, lightning at distance not more than hundreds km from satellite detector field of view in the atmosphere and 2. transients generated by far away lightning. Local transients are luminous and presumably are events called "transient luminous events" (TLE). In distribution on luminosity those events have some threshold Q~1023 and their differential luminosity distribution is approximated by power law exponent "-2". Remote transients have to be considered separately. Their

  10. The Maximum Free Magnetic Energy Allowed in a Solar Active Region

    NASA Technical Reports Server (NTRS)

    Moore, Ronald L.; Falconer, David A.

    2009-01-01

    Two whole-active-region magnetic quantities that can be measured from a line-of-sight magnetogram are (sup L) WL(sub SG), a gauge of the total free energy in an active region's magnetic field, and sup L(sub theta), a measure of the active region's total magnetic flux. From these two quantities measured from 1865 SOHO/MDI magnetograms that tracked 44 sunspot active regions across the 0.5 R(sub Sun) central disk, together with each active region's observed production of CMEs, X flares, and M flares, Falconer et al (2009, ApJ, submitted) found that (1) active regions have a maximum attainable free magnetic energy that increases with the magnetic size (sup L) (sub theta) of the active region, (2) in (Log (sup L)WL(sub SG), Log(sup L) theta) space, CME/flare-productive active regions are concentrated in a straight-line main sequence along which the free magnetic energy is near its upper limit, and (3) X and M flares are restricted to large active regions. Here, from (a) these results, (b) the observation that even the greatest X flares produce at most only subtle changes in active region magnetograms, and (c) measurements from MSFC vector magnetograms and from MDI line-of-sight magnetograms showing that practically all sunspot active regions have nearly the same area-averaged magnetic field strength: =- theta/A approximately equal to 300 G, where theta is the active region's total photospheric flux of field stronger than 100 G and A is the area of that flux, we infer that (1) the maximum allowed ratio of an active region's free magnetic energy to its potential-field energy is 1, and (2) any one CME/flare eruption releases no more than a small fraction (less than 10%) of the active region's free magnetic energy. This work was funded by NASA's Heliophysics Division and NSF's Division of Atmospheric Sciences.

  11. Local generation of multineuronal spike sequences in the hippocampal CA1 region

    PubMed Central

    Stark, Eran; Roux, Lisa; Eichler, Ronny; Buzsáki, György

    2015-01-01

    Sequential activity of multineuronal spiking can be observed during theta and high-frequency ripple oscillations in the hippocampal CA1 region and is linked to experience, but the mechanisms underlying such sequences are unknown. We compared multineuronal spiking during theta oscillations, spontaneous ripples, and focal optically induced high-frequency oscillations (“synthetic” ripples) in freely moving mice. Firing rates and rate modulations of individual neurons, and multineuronal sequences of pyramidal cell and interneuron spiking, were correlated during theta oscillations, spontaneous ripples, and synthetic ripples. Interneuron spiking was crucial for sequence consistency. These results suggest that participation of single neurons and their sequential order in population events are not strictly determined by extrinsic inputs but also influenced by local-circuit properties, including synapses between local neurons and single-neuron biophysics. PMID:26240336

  12. Generation and detection of super small striations by F region HF heating

    NASA Astrophysics Data System (ADS)

    Najmi, A.; Milikh, G.; Secan, J.; Chiang, K.; Psiaki, M.; Bernhardt, P.; Briczinski, S.; Siefring, C.; Chang, C. L.; Papadopoulos, K.

    2014-07-01

    Recent theoretical models and preliminary observations indicate that super small striations (SSS) in the plasma density with scale size of 10 cm can be excited by F region HF heating at frequencies close to multiples of the electron gyrofrequency. We present here new experimental results using the High Frequency Active Auroral Research Program ionospheric heater at a frequency close to the fourth electron gyroharmonic with simultaneous GPS, Stimulated Electromagnetic Emission, ionosonde, and occasional Incoherent Radar Scattering diagnostics. Differential phase measurements of GPS signals through the heated region indicated the presence of SSS with extremely high amplitude (δn/n = 0.2-0.3) at scale size comparable to the electron gyroradius. The highest amplitude of GPS scintillations coincide with the highest level of the Broad Upshifted Maximum (BUM) and occurred when the HF frequency is slightly above the fourth harmonic of the electron cyclotron frequency. Frequency sweeps indicate that the scintillation amplitude exhibits hysteresis similar to that observed for the BUM amplitude when the HF frequency is cycled about the fourth harmonic of the cyclotron frequency. The results favor a four wave parametric process as the physical mechanism of the SSS. Additional experiments allowed the determination of the excitation and decay rates of the SSS.

  13. Chemical and conformational changes in chromosome regions being actively transcribed.

    PubMed Central

    Pagés, M; Alonso, C

    1978-01-01

    U.V. microspectrophotometry has been used to calculate quantities of nucleic acids and proteins of complete polytene chromosomal sets and specific regions of these chromosomes. It has been found that in chromosomes the ratio of DNA to proteins is approximately 1:4. This ratio however changes when specific regions are compared. The average ratio of DNA to proteins in a puffed region (2-48B4C5) increases to 1:16 in contrast to 1:6 from the same region but in non puffed state. At the same time the RNA quantity increases by a factor of 2. thermal denaturation profiles of formaldehyde fixed chromosomes show that the Tm of this region in puffed and non puffed state differ by 10 degrees C. Moreover these profiles suggest that a large fraction of histone-bound DNA is destabilized during puffing. PMID:634798

  14. Assessing Neutron Generator Output Using Delayed Activation of Silicon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deuterium-tritium (D-T) neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when t...

  15. Fourth Generation Instructional Design Model: An Elaboration on Authoring Activities.

    ERIC Educational Resources Information Center

    Christensen, Dean L.

    This paper presents the updated (fourth generation) version of the instructional design (ID) model, noting its emphasis on a scientific, iterative approach based upon research and theory in learning and instruction and upon applied development experience. Another important trend toward a scientific approach to instructional design is the increased…

  16. A low upper limit on the subsurface rise speed of solar active regions

    PubMed Central

    Birch, Aaron C.; Schunker, Hannah; Braun, Douglas C.; Cameron, Robert; Gizon, Laurent; Löptien, Björn; Rempel, Matthias

    2016-01-01

    Magnetic field emerges at the surface of the Sun as sunspots and active regions. This process generates a poloidal magnetic field from a rising toroidal flux tube; it is a crucial but poorly understood aspect of the solar dynamo. The emergence of magnetic field is also important because it is a key driver of solar activity. We show that measurements of horizontal flows at the solar surface around emerging active regions, in combination with numerical simulations of solar magnetoconvection, can constrain the subsurface rise speed of emerging magnetic flux. The observed flows imply that the rise speed of the magnetic field is no larger than 150 m/s at a depth of 20 Mm, that is, well below the prediction of the (standard) thin flux tube model but in the range expected for convective velocities at this depth. We conclude that convective flows control the dynamics of rising flux tubes in the upper layers of the Sun and cannot be neglected in models of flux emergence. PMID:27453947

  17. A low upper limit on the subsurface rise speed of solar active regions.

    PubMed

    Birch, Aaron C; Schunker, Hannah; Braun, Douglas C; Cameron, Robert; Gizon, Laurent; Löptien, Björn; Rempel, Matthias

    2016-07-01

    Magnetic field emerges at the surface of the Sun as sunspots and active regions. This process generates a poloidal magnetic field from a rising toroidal flux tube; it is a crucial but poorly understood aspect of the solar dynamo. The emergence of magnetic field is also important because it is a key driver of solar activity. We show that measurements of horizontal flows at the solar surface around emerging active regions, in combination with numerical simulations of solar magnetoconvection, can constrain the subsurface rise speed of emerging magnetic flux. The observed flows imply that the rise speed of the magnetic field is no larger than 150 m/s at a depth of 20 Mm, that is, well below the prediction of the (standard) thin flux tube model but in the range expected for convective velocities at this depth. We conclude that convective flows control the dynamics of rising flux tubes in the upper layers of the Sun and cannot be neglected in models of flux emergence. PMID:27453947

  18. Characteristics in the jet region of helium radio-frequency atmospheric-pressure glow discharge with array generators

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Bin; Nie, Qiu-Yue

    2015-09-01

    The two-dimensional spatially extended atmospheric plasma arrays by many parallel radio-frequency glow discharge plasma jets packed densely, represent a feature option of large-scale low-temperature atmospheric plasma technologies with distinct capability of directed delivery of reactive species and good insusceptibility to sample variations. However, it is still a challenge to form plasma jet with large area of uniform active species on a downstream substrate due to the complex interactions between individual jets. This paper proposes to numerically study the strategy and mechanism of control/modulation for the array discharge to produce two-dimensional plasma uniformity in the downstream working area. In this work, a two dimensional fluid model is employed to investigate the characteristics in the jet region of helium radio-frequency atmospheric-pressure glow discharge (RF APGD) with array generators. The influences of upstream discharge characteristics, gas flow and their cooperative effects on the distribution of species densities, gas temperatures and the uniformity of active species in the material treating area is studied, and the essential strategy for the modulation method is acquired. The results will be significant for deep understanding of coupling behaviors of multiple plasma plumes in the RF APGD array and applications of the technology.

  19. Probing the central regions of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Lohfink, Anne Maria

    Active Galactic Nuclei (AGN) are one of the key players in the Universe. Their energy output can strongly affect the growth of their host galaxy and can promote or suppress star formation on galactic scales. Most of the processes that determine the power of an AGN as well as the form in which that power is released take place in the immediate surroundings of its supermassive black hole, a region that is still not entirely understood. A comprehension of these inner regions is, however, crucial to any ultimate understanding of the AGN's vast influence. This dissertation explores these close-in environments of the black hole using two approaches: X-ray spectroscopy and variability studies. We begin by summarizing our current understanding of why AGN play such a significant role in galaxy formation. This is followed by a discussion of why X-ray spectroscopy is one of the best means to investigate them. We point out that, in particular, the X-ray reflection spectrum is interesting as it can directly probe parameters such as the black hole spin or the inclination of the accretion disk. Since the reflection spectrum is a broad band component, that usually only contributes a fraction of the total observed X-ray flux, the entire X-ray spectrum requires careful modeling. To perform such modeling and gain access to the parameters of the reflection spectrum, we first select a target in which the spectral decomposition is simplified by the absence of absorption - the Seyfert 1 galaxy Fairall 9. We apply a multi-epoch fitting method that uses more than one spectrum at a time to get the best possible results on the parameters of the reflection spectrum that are invariant on human timescales. This technique enables us to tightly constrain the reflection parameters and leads us to conclude that Fairall 9 most likely possesses a composite soft X-ray excess, consisting of blurred reflection and a separate component such as Comptonization. The reflection spectrum also provides a way

  20. Regional variations in the health, environmental, and climate benefits of wind and solar generation.

    PubMed

    Siler-Evans, Kyle; Azevedo, Inês Lima; Morgan, M Granger; Apt, Jay

    2013-07-16

    When wind or solar energy displace conventional generation, the reduction in emissions varies dramatically across the United States. Although the Southwest has the greatest solar resource, a solar panel in New Jersey displaces significantly more sulfur dioxide, nitrogen oxides, and particulate matter than a panel in Arizona, resulting in 15 times more health and environmental benefits. A wind turbine in West Virginia displaces twice as much carbon dioxide as the same turbine in California. Depending on location, we estimate that the combined health, environmental, and climate benefits from wind or solar range from $10/MWh to $100/MWh, and the sites with the highest energy output do not yield the greatest social benefits in many cases. We estimate that the social benefits from existing wind farms are roughly 60% higher than the cost of the Production Tax Credit, an important federal subsidy for wind energy. However, that same investment could achieve greater health, environmental, and climate benefits if it were differentiated by region. PMID:23798431

  1. Summary of three regional assessment studies of solar electric generation opportunities in the Southwest, Southeast, and Northeast United States

    SciTech Connect

    Watts, R.L.; Harty, H.

    1981-02-01

    Market opportunities for solar generation of electricity for utility and for residential/commercial/industrial applications in the Northeast, Southeast, and Southwest regions of the United States were evaluated in three studies (JBF 1979, Stone and Webster 1979a, 1979b) and are summarized. The evaluations were based on both economic analyses and user perception of what they would require to select or approve the use of solar electric generation for themselves or for their employers. Over 30 utilities and several industrial and commercial firms and homeowners were involved. Solar electric technologies considered included biomass, hybrid retrofit, OTEC, photovoltaic, solar thermal, and wind. The studies projected that solar electric technologies could account for several percent of the forecast generation in year 2000 in the Southeast and Southwest regions,and up to 10 to 20% in the Northeast region. No single solar electric technology or application (for utility or industrial/commercial/residential use) arrived earlier at economic breakeven than other technologies in the Southeast region, but wind generation for both utility and industrial applications predominated in the Northeast region. The Southwest region, in which only utility applications were considered, showed wind energy and retrofit hybrid (a solar adjunct to an existing fossil-fueled plant) to be the most likely early applications.

  2. Application of active quenching of second generation wire for current limiting

    SciTech Connect

    Solovyov, Vyacheslav F.; Li, Qiang

    2015-10-19

    Superconducting fault current limiters (SFCL's) are increasingly implemented in the power grid as a protection of substation equipment from fault currents. Resistive SFCL's are compact and light, however they are passively triggered and thus may not be sufficiently sensitive to respond to faults in the distribution grid. Here, we explore the prospect of adding an active management feature to a traditional resistive SFCL. A flexible radio-frequency coil, which is an integral part of the switching structure, acts as a triggering device. We show that the application of a short, 10 ms, burst of ac magnetic field during the fault triggers a uniform quench of the wire and significantly reduces the reaction time of the wire at low currents. The ac field burst generates a high density of normal zones, which merge into a continuous resistive region at a rate much faster than that of sparse normal zones created by the transport current alone.

  3. Application of active quenching of second generation wire for current limiting

    DOE PAGESBeta

    Solovyov, Vyacheslav F.; Li, Qiang

    2015-10-19

    Superconducting fault current limiters (SFCL's) are increasingly implemented in the power grid as a protection of substation equipment from fault currents. Resistive SFCL's are compact and light, however they are passively triggered and thus may not be sufficiently sensitive to respond to faults in the distribution grid. Here, we explore the prospect of adding an active management feature to a traditional resistive SFCL. A flexible radio-frequency coil, which is an integral part of the switching structure, acts as a triggering device. We show that the application of a short, 10 ms, burst of ac magnetic field during the fault triggersmore » a uniform quench of the wire and significantly reduces the reaction time of the wire at low currents. The ac field burst generates a high density of normal zones, which merge into a continuous resistive region at a rate much faster than that of sparse normal zones created by the transport current alone.« less

  4. generation of picosecond pulses in solid-state lasers using new active media

    SciTech Connect

    Lisitsyn, V.N.; Matrosov, V.N.; Pestryakov, E.V.; Trunov, V.I.

    1986-07-01

    Results are reported of investigations aimed at generating nanosecond radiation pulses in solid-state lasers using new active media having broad gain lines. Passive mode locking is accomplished for the first time in a BeLa:Nd/sup 3/ laser at a wavelength 1.354 microm, and in a YAG:Nd/sup 3/ laser on a 1.32-microm transition. The free lasing and mode-locking regimes were investigated in an alexandrite (BeA1/sub 2/O/sub 4/:Cr/sup 3/) laser in the 0.72-0.78-microm range and in a synchronously pumped laser on F/sub 2//sup -/ centers in LiF in the 1.12-1.24-microm region. The features of nonlinear perception of IR radiation by the eye, using a developed picosecond laser on F/sub 2//sup -/ centers, are investigated for the first time.

  5. Application of active quenching of second generation wire for current limiting

    NASA Astrophysics Data System (ADS)

    Solovyov, Vyacheslav F.; Li, Qiang

    2015-12-01

    Superconducting fault current limiters (SFCLs) are increasingly implemented in the power grid as a protection of substation equipment from fault currents. Resistive SFCLs are compact and light, however they are passively triggered and thus may not be sufficiently sensitive to respond to faults in the distribution grid. Here, we explore the prospect of adding an active management feature to a traditional resistive SFCL. A flexible radio-frequency coil, which is an integral part of the switching structure, acts as a triggering device. We show that the application of a short, 10 ms, burst of ac magnetic field during the fault triggers a uniform quench of the wire and significantly reduces the reaction time of the wire at low currents. The ac field burst generates a high density of normal zones, which merge into a continuous resistive region at a rate much faster than that of sparse normal zones created by the transport current alone.

  6. Liposomal packaging generates Wnt protein with in vivo biological activity.

    PubMed

    Morrell, Nathan T; Leucht, Philipp; Zhao, Ludan; Kim, Jae-Beom; ten Berge, Derk; Ponnusamy, Karthik; Carre, A Lyonel; Dudek, Henryk; Zachlederova, Marie; McElhaney, Michael; Brunton, Shirley; Gunzner, Janet; Callow, Marinella; Polakis, Paul; Costa, Mike; Zhang, Xiaoyan M; Helms, Jill A; Nusse, Roel

    2008-01-01

    Wnt signals exercise strong cell-biological and regenerative effects of considerable therapeutic value. There are, however, no specific Wnt agonists and no method for in vivo delivery of purified Wnt proteins. Wnts contain lipid adducts that are required for activity and we exploited this lipophilicity by packaging purified Wnt3a protein into lipid vesicles. Rather than being encapsulated, Wnts are tethered to the liposomal surface, where they enhance and sustain Wnt signaling in vitro. Molecules that effectively antagonize soluble Wnt3a protein but are ineffective against the Wnt3a signal presented by a cell in a paracrine or autocrine manner are also unable to block liposomal Wnt3a activity, suggesting that liposomal packaging mimics the biological state of active Wnts. When delivered subcutaneously, Wnt3a liposomes induce hair follicle neogenesis, demonstrating their robust biological activity in a regenerative context. PMID:18698373

  7. THE LIMIT OF MAGNETIC-SHEAR ENERGY IN SOLAR ACTIVE REGIONS

    SciTech Connect

    Moore, Ronald L.; Falconer, David A.; Sterling, Alphonse C.

    2012-05-01

    It has been found previously, by measuring from active-region magnetograms a proxy of the free energy in the active region's magnetic field, (1) that there is a sharp upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region's magnetic flux content, and (2) that most active regions are near this limit when their field explodes in a coronal mass ejection/flare eruption. That is, explosive active regions are concentrated in a main-sequence path bordering the free-energy-limit line in (flux content, free-energy proxy) phase space. Here, we present evidence that specifies the underlying magnetic condition that gives rise to the free-energy limit and the accompanying main sequence of explosive active regions. Using a suitable free-energy proxy measured from vector magnetograms of 44 active regions, we find evidence that (1) in active regions at and near their free-energy limit, the ratio of magnetic-shear free energy to the non-free magnetic energy the potential field would have is of the order of one in the core field, the field rooted along the neutral line, and (2) this ratio is progressively less in active regions progressively farther below their free-energy limit. Evidently, most active regions in which this core-field energy ratio is much less than one cannot be triggered to explode; as this ratio approaches one, most active regions become capable of exploding; and when this ratio is one, most active regions are compelled to explode.

  8. The Limit of Magnetic-Shear Energy in Solar Active Regions

    NASA Technical Reports Server (NTRS)

    Moore, Ronald; Falconer, David; Sterling, Alphonse

    2012-01-01

    It has been found previously, by measuring from active-region magnetograms a proxy of the free energy in the active region's magnetic field, (1) that there is a sharp upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region's magnetic flux content, and (2) that most active regions are near this limit when their field explodes in a coronal mass ejection/flare eruption. That is, explosive active regions are concentrated in a main-sequence path bordering the free-energy-limit line in (flux content, free-energy proxy) phase space. Here, we present evidence that specifies the underlying magnetic condition that gives rise to the free-energy limit and the accompanying main sequence of explosive active regions. Using a suitable free-energy proxy measured from vector magnetograms of 44 active regions, we find evidence that (1) in active regions at and near their free-energy limit, the ratio of magnetic-shear free energy to the non-free magnetic energy the potential field would have is of the order of one in the core field, the field rooted along the neutral line, and (2) this ratio is progressively less in active regions progressively farther below their free-energy limit. Evidently, most active regions in which this core-field energy ratio is much less than one cannot be triggered to explode; as this ratio approaches one, most active regions become capable of exploding; and when this ratio is one, most active regions are compelled to explode.

  9. The Limit of Magnetic-Shear Energy in Solar Active Regions

    NASA Technical Reports Server (NTRS)

    Moore, Ronald L.; Falconer, David A.; Sterling, Alphonse C.

    2013-01-01

    It has been found previously, by measuring from active ]region magnetograms a proxy of the free energy in the active region fs magnetic field, (1) that there is a sharp upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region fs magnetic flux content, and (2) that most active regions are near this limit when their field explodes in a CME/flare eruption. That is, explosive active regions are concentrated in a main ]sequence path bordering the free ]energy ]limit line in (flux content, free ]energy proxy) phase space. Here we present evidence that specifies the underlying magnetic condition that gives rise to the free ]energy limit and the accompanying main sequence of explosive active regions. Using a suitable free energy proxy measured from vector magnetograms of 44 active regions, we find evidence that (1) in active regions at and near their free ]energy limit, the ratio of magnetic ]shear free energy to the non ]free magnetic energy the potential field would have is of order 1 in the core field, the field rooted along the neutral line, and (2) this ratio is progressively less in active regions progressively farther below their free ]energy limit. Evidently, most active regions in which this core ]field energy ratio is much less than 1 cannot be triggered to explode; as this ratio approaches 1, most active regions become capable of exploding; and when this ratio is 1, most active regions are compelled to explode.

  10. Next-generation active immunization approach for synucleinopathies - implications for Parkinson’s Disease clinical trials

    PubMed Central

    Mandler, Markus; Valera, Elvira; Rockenstein, Edward; Weninger, Harald; Patrick, Christina; Adame, Anthony; Santic, Radmila; Meindl, Stefanie; Vigl, Benjamin; Smrzka, Oskar; Schneeberger, Achim; Mattner, Frank; Masliah, Eliezer

    2014-01-01

    Immunotherapeutic approaches are currently in the spotlight for their potential as disease-modifying treatments for neurodegenerative disorders. The discovery that α-synuclein (α-syn) can transmit from cell to cell in a prion-like fashion suggests that immunization might be a viable option for the treatment of synucleinopathies. This possibility has been bolstered by the development of next-generation active vaccination technology with short peptides-AFFITOPEs® (AFF) that do not elicit a α-syn specific T-cell response. This approach allows the generation of long-term sustained, more specific, non-cross reacting antibodies suitable for the treatment of synucleinopathies such as Parkinson’s disease (PD). In this context, we screened a large library of peptides that mimic the c-terminus region of α-syn and discovered a novel set of AFF that identified α-syn oligomers. Next, the peptide that elicited the most specific response against α-syn (AFF 1) was selected for immunizing two different transgenic mouse models of PD and Dementia with Lewy bodies (DLB), the PDGF- and the mThy1-α-syn tg mice. Vaccination with AFF 1 resulted in high antibody titers in CSF and plasma, which crossed into the CNS and recognized α-syn aggregates. Active vaccination with AFF 1 resulted in decreased accumulation of α-syn oligomers in axons and synapses that was accompanied by reduced degeneration of TH fibers in the caudo-putamen nucleus and by improvements in motor and memory deficits in both in vivo models. Clearance of α-syn involved activation of microglia and increased anti-inflammatory cytokine expression, further supporting the efficacy of this novel active vaccination approach for synucleinopathies. PMID:24525765

  11. Biological activity of photoproducts of merocyanine 540 generated by laser-light activation

    NASA Astrophysics Data System (ADS)

    Gulliya, Kirpal S.; Chanh, Tran C.; Pervaiz, Shazib; Harriman, Anthony; Matthews, James Lester

    1992-08-01

    Controlled exposure of photoactive compounds to light prior to their use in biological targets results in the formation of heretofore unknown photoproducts. This process of photoproduct generation, termed "preactivation," renders the photactive compound capable of systemic use without further dependence on light. Preactivation of mercyanin 540 (MC540) and several other photoactive compounds is achievable by exposure to CW and pulse laser radiation. The singlet oxygen generated at excited states attacks the dye molucule itself, resulting in the formation of biologically active photoproducts. For preactivated MC540 (photoproducts of MC540) generated by exposure to argon laser light (514 nm) and light from free-electron laser, we have demonstrated its effectiveness in selective killing of certain types of cultured tumor cells as well as human immunodeficiency virus type 1 (HIV-1) with very low, if any, damage to normal cells and tisues. For example, approximately 90% of the Burkitt's lymphoma Daudi cells and HL-60 leukemic cells are killed by preactivated MC540 at a concentration of 120 μg/ml. A two-hour treatment of cultured cells with buthionine sulfoxamine followed by the treatement with preactivated MC540 reults in 99.99% inhibition of clonogenic tumor stem cell growth. We also have demonstrated that preactivated MC540 is very effective in killing cell-free and cell-associated HIV-1. It also is very effective in killing HIV-1 and simian immunodeficiency virus (SIV) in virus-infected blood in vitro as determined by reverse transcriptase, P24, P17, core antigen expression and synctium formation. Treatment of HIV-1 with preactivated MC540 renders the treated HIV-1 incapable of binding to CD4 target molecules on T cells as determined by immunofluorescence and radioimmunoprecipitation assays. In vivo toxicology studies show that preactivated MC540 is very well tolerated and does not produce any signs of adverse reaction at the therapeutic doses, as determined by

  12. Next-Generation Satellite Precipitation Products for Understanding Global and Regional Water Variability

    NASA Technical Reports Server (NTRS)

    Hou, Arthur Y.

    2011-01-01

    A major challenge in understanding the space-time variability of continental water fluxes is the lack of accurate precipitation estimates over complex terrains. While satellite precipitation observations can be used to complement ground-based data to obtain improved estimates, space-based and ground-based estimates come with their own sets of uncertainties, which must be understood and characterized. Quantitative estimation of uncertainties in these products also provides a necessary foundation for merging satellite and ground-based precipitation measurements within a rigorous statistical framework. Global Precipitation Measurement (GPM) is an international satellite mission that will provide next-generation global precipitation data products for research and applications. It consists of a constellation of microwave sensors provided by NASA, JAXA, CNES, ISRO, EUMETSAT, DOD, NOAA, NPP, and JPSS. At the heart of the mission is the GPM Core Observatory provided by NASA and JAXA to be launched in 2013. The GPM Core, which will carry the first space-borne dual-frequency radar and a state-of-the-art multi-frequency radiometer, is designed to set new reference standards for precipitation measurements from space, which can then be used to unify and refine precipitation retrievals from all constellation sensors. The next-generation constellation-based satellite precipitation estimates will be characterized by intercalibrated radiometric measurements and physical-based retrievals using a common observation-derived hydrometeor database. For pre-launch algorithm development and post-launch product evaluation, NASA supports an extensive ground validation (GV) program in cooperation with domestic and international partners to improve (1) physics of remote-sensing algorithms through a series of focused field campaigns, (2) characterization of uncertainties in satellite and ground-based precipitation products over selected GV testbeds, and (3) modeling of atmospheric processes and

  13. Generation and secretion of eosinophilotactic activity from human polymorphonuclear neutrophils by various mechanisms of cell activation.

    PubMed Central

    König, W; Frickhofen, N; Tesch, H

    1979-01-01

    An eosinophil chemotactic factor(s) (ECF) can be generated from human polymorphonuclear neutrophils by the calcium ionophore, phagocytosis, arachidonic acid and hypotonic lysis. In kinetic studies it is observed that peak ECF activity is released prior to the maximum of lysosomal enzyme release with the calcium ionophore, phagocytosis and arachidonic acid, while under conditions of hypotonic exposure ECF activity appears after the maximum of enzyme release. The ECF obtained by hypotonic exposure shows a fluctuating pattern with sharp peaks and steep fall-offs in activity. The ECF-release for each stimulus is temperature dependent; extracellular calcium is required when the ionophore or phagocytosis are used as stimuli, while with arachidonic acid and hypotonic exposure no extracellular calcium is necessary for ECF-release. On Sephadex G-25 each preparation of ECF eluted in the low molecular weight range at approximately 500 daltons. Eosinophils can be deactivated and cross-deactivated with the various ECF-preparations indicating either a molecular identity or a common mode of action on eosinophils. PMID:437847

  14. Orientation of functional activating regions in the Escherichia coli CRP protein during transcription activation at class II promoters.

    PubMed Central

    Williams, R M; Rhodius, V A; Bell, A I; Kolb, A; Busby, S J

    1996-01-01

    At class II CRP-dependent promoters the DNA site for CRP overlaps the DNA site for RNA polymerase, covering the -35 region. Transcription activation at class II CRP- dependent promoters requires a contact between an activating region in the upstream subunit of the bound CRP dimer and a contact site in the C-terminal domain of the alpha-subunit of RNA polymerase. Transcription activation is suppressed by amino acid substitutions in the activating region, but activation can be restored by second site substitutions at K52 or E96. These substitutions identify two separate regions on the surface of CRP that appear to be able to interact with RNA polymerase specifically at class II promoters. Using the method of 'oriented heterodimers' we show that these alternative activating regions are functional in the downstream subunit of the bound CRP dimer. PMID:8604346

  15. Analysis of body calcium (regional changes in body calcium by in vivo neutron activation analysis)

    NASA Technical Reports Server (NTRS)

    Suki, W.; Johnson, P. C.; Leblanc, A.; Evans, H. J.

    1981-01-01

    The effect of space flight on urine and fecal calcium loss was documented during the three long-term Skylab flights. Neutron activation analysis was used to determine regional calcium loss. Various designs for regional analysis were investigated.

  16. Conditionally-Sampled Turbulent and Non-turbulent Measurements of Entropy Generation Rate in the Transition Region of Boundary Layers

    SciTech Connect

    Edmond J. Walsh; Kevin P. Nolan; Donald M. McEligot; Ralph J. Volino; Adrian Bejan

    2007-05-01

    Conditionally-sampled boundary layer data for an accelerating transitional boundary layer have been analyzed to calculate the entropy generation rate in the transition region. By weighing the nondimensional dissipation coefficient for the laminar-conditioned-data and turbulent-conditioned-data with the intermittency factor the average entropy generation rate in the transition region can be determined and hence be compared to the time averaged data and correlations for steady laminar and turbulent flows. It is demonstrated that this method provides, for the first time, an accurate and detailed picture of the entropy generation rate during transition. The data used in this paper have been taken from detailed boundary layer measurements available in the literature. This paper provides, using an intermittency weighted approach, a methodology for predicting entropy generation in a transitional boundary layer.

  17. Effect of tidal stream power generation on the region-wide circulation in a shallow sea

    NASA Astrophysics Data System (ADS)

    Shapiro, G. I.

    2011-02-01

    This paper quantifies the backward effect on the ocean currents caused by a tidal stream farm located in the open shallow sea. Recent studies in channels with 1-D models have indicated that the power potential is not given purely by the flux of kinetic energy, as has been commonly assumed. In this study, a 3-D ocean circulation model is used to estimate (i) practically extractable energy resource at different levels of rated generation capacity of the farm, (ii) changes in the strength of currents due to energy extraction, and (iii) alterations in the pattern of residual currents and the pathways of passive tracers. As well as tidal streams, the model also takes into account the wind-driven and density-driven ocean currents. Numerical modelling has been carried out for a hypothetical tidal farm located in the Celtic Sea north of Cornwall, an area known for its high level of tidal energy. Modelling results clearly indicate that the extracted power does not grow linearly with the increase in the rated capacity of the farm. For the case study covered in this paper, a 100-fold increase in the rated generation capacity of the farm results in only 7-fold increase in extracted power. In the case of a high power farm, kinetic energy of currents is altered significantly as far as 10-20 km away from the farm. At high levels of extracted energy the currents tend to avoid flowing through the farm, an effect which is not captured with 1-D models. Residual currents are altered as far as a hundred kilometres away. The magnitude of changes in the dispersion of tracers is highly sensitive to the location. Some of the passive drifters analysed in this study experience significant variations in the end-to-start distance due to energy extraction ranging from 13% to 238% while others are practically unaffected. This study shows that both energy extraction estimates and effects on region wide circulation depend on a complex combination of factors, and the specific figures given in the

  18. Identification of conserved genomic regions and variation therein amongst Cetartiodactyla species using next generation sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background Next Generation Sequencing has created an opportunity to genetically characterize an individual both inexpensively and comprehensively. In earlier work produced in our collaboration [1], it was demonstrated that, for animals without a reference genome, their Next Generation Sequence data ...

  19. Linking the Weather Generator with Regional Climate Model: Effect of Higher Resolution

    NASA Astrophysics Data System (ADS)

    Dubrovsky, Martin; Huth, Radan; Farda, Ales; Skalak, Petr

    2014-05-01

    This contribution builds on our last year EGU contribution, which followed two aims: (i) validation of the simulations of the present climate made by the ALADIN-Climate Regional Climate Model (RCM) at 25 km resolution, and (ii) presenting a methodology for linking the parametric weather generator (WG) with RCM output (aiming to calibrate a gridded WG capable of producing realistic synthetic multivariate weather series for weather-ungauged locations). Now we have available new higher-resolution (6.25 km) simulations with the same RCM. The main topic of this contribution is an anser to a following question: What is an effect of using a higher spatial resolution on a quality of simulating the surface weather characteristics? In the first part, the high resolution RCM simulation of the present climate will be validated in terms of selected WG parameters, which are derived from the RCM-simulated surface weather series and compared to those derived from weather series observed in 125 Czech meteorological stations. The set of WG parameters will include statistics of the surface temperature and precipitation series. When comparing the WG parameters from the two sources (RCM vs observations), we interpolate the RCM-based parameters into the station locations while accounting for the effect of altitude. In the second part, we will discuss an effect of using the higher resolution: the results of the validation tests will be compared with those obtained with the lower-resolution RCM. Acknowledgements: The present experiment is made within the frame of projects ALARO-Climate (project P209/11/2405 sponsored by the Czech Science Foundation), WG4VALUE (project LD12029 sponsored by the Ministry of Education, Youth and Sports of CR) and VALUE (COST ES 1102 action).

  20. The multi-thermal emission in solar active regions

    NASA Astrophysics Data System (ADS)

    Del Zanna, G.

    2013-10-01

    We present simultaneous SDO AIA and Hinode EIS observations of the hot cores of active regions (ARs) and assess the dominant contributions to the AIA EUV bands. This is an extension of our previous work. We find good agreement between SDO AIA, EVE and EIS observations, using our new EIS calibration and the latest EVE v.3 data. We find that all the AIA bands are multi-thermal, with the exception of the 171 and 335 Å, and provide ways to roughly estimate the main contributions directly from the AIA data. We present and discuss new atomic data for the AIA bands, showing that they are now sufficiently complete to obtain temperature information in the cores of ARs, with the exception of the 211 Å band. We found that the newly identified Fe xiv 93.61 Å line is the dominant contribution to the 94 Å band, whenever Fe xviii is not present. Three methods to estimate the Fe xviii emission in this band are presented, two using EIS and one directly from the AIA data. Fe xviii emission is often present in the cores of ARs, but we found cases where it is formed at 3 MK and not 7 MK, the temperature of peak ion abundance in equilibrium. The best EIS lines for elemental abundance determination and differential emission measure (DEM) analysis are discussed. A new set of abundances for many elements are obtained from EIS observations of hot 3 MK loops. The abundances of the elements with low first ionisation potential (FIP), relative to those of the high-FIP elements, are found to be enhanced by about a factor of three, compared to the photospheric values. A measurement of the path length implies that the absolute abundances of the low-FIP elements are higher than the photospheric values by at least a factor of three. We present a new DEM method customised for the AIA bands, to study the thermal structure of ARs at 1'' resolution. This was tested on a few ARs, including one observed during the Hi-C rocket flight. We found excellent agreement between predicted and observed AIA

  1. The solar atmosphere and the structure of active regions

    NASA Technical Reports Server (NTRS)

    Sturrock, P. A.

    1974-01-01

    The existence of 'holes' in the corona is reported characterized by abnormally low densities and temperatures. It was found that such coronal holes appear to be the source of high-velocity, enhanced-density streams in the solar wind as observed at the earth's orbit. It was further noted that coronal holes appear to be associated with regions of diverging magnetic fields in the corona. Models were developed to accomplish the objective for the principal energy flows in the transition region and corona.

  2. Using Guided, Corpus-Aided Discovery to Generate Active Learning

    ERIC Educational Resources Information Center

    Huang, Li-Shih

    2008-01-01

    Over the years, educators have proposed a variety of active learning pedagogical approaches that focus on encouraging students to discover for themselves the principles and solutions that will engage them in learning and enhance their educational outcomes. Among these approaches are problem-based, inquiry-based, experiential, and discovery…

  3. Educating for Political Activity: A Younger Generational Response

    ERIC Educational Resources Information Center

    Mac an Ghaill, Mairtin

    2010-01-01

    This paper is a response to Professor Chitty's "Educational Review" Guest Lecture article, "Educating for political activity". I address the three sections of his paper: a global and national-based politics of war, corporate manipulation and parliamentary scandals. This provides a basis to draw upon empirical material from a recent critical…

  4. Designed and User-Generated Activity in the Mobile Age

    ERIC Educational Resources Information Center

    Kukulska-Hulme, Agnes; Traxler, John; Pettit, John

    2007-01-01

    The paper addresses the question of how to design for learning taking place on mobile and wireless devices. The authors argue that learning activity designers need to consider the characteristics of mobile learning; at the same time, it is vital to realise that learners are already creating mobile learning experiences for themselves. Profound…

  5. Antibody Constant Region Peptides Can Display Immunomodulatory Activity through Activation of the Dectin-1 Signalling Pathway

    PubMed Central

    Cenci, Elio; Monari, Claudia; Magliani, Walter; Ciociola, Tecla; Conti, Stefania; Gatti, Rita; Bistoni, Francesco; Polonelli, Luciano; Vecchiarelli, Anna

    2012-01-01

    We previously reported that a synthetic peptide with sequence identical to a CDR of a mouse monoclonal antibody specific for difucosyl human blood group A exerted an immunomodulatory activity on murine macrophages. It was therapeutic against systemic candidiasis without possessing direct candidacidal properties. Here we demonstrate that a selected peptide, N10K, putatively deriving from the enzymatic cleavage of the constant region (Fc) of human IgG1, is able to induce IL-6 secretion and pIkB-α activation. More importantly, it causes an up-regulation of Dectin-1 expression. This leads to an increased activation of β-glucan-induced pSyk, CARD9 and pIkB-α, and an increase in the production of pro-inflammatory cytokines such as IL-6, IL-12, IL-1β and TNF-α. The increased activation of this pathway coincides with an augmented phagocytosis of non opsonized Candida albicans cells by monocytes. The findings suggest that some Fc-peptides, potentially deriving from the proteolysis of immunoglobulins, may cause an unexpected immunoregulation in a way reminiscent of innate immunity molecules. PMID:22952831

  6. A restricted parabrachial pontine region is active during non-REM sleep

    PubMed Central

    Torterolo, Pablo; Sampogna, Sharon; Chase, Michael H.

    2011-01-01

    The principal site that generates both REM sleep and wakefulness is located in the mesopontine reticular formation, whereas non-REM sleep (NREM) is primarily dependent upon the functioning of neurons that are located in the preoptic region of the hypothalamus. In the present study, we were interested in determining whether the occurrence of NREM might also depend on the activity of mesopontine structures, as has been shown for wakefulness and REM sleep. Adult cats were maintained in one of the following states: quiet wakefulness (QW), alert wakefulness (AW), NREM, or REM sleep induced by microinjections of carbachol into the nucleus pontis oralis (REM-carbachol). Subsequently, they were euthanized and single labeling immunohistochemical studies were undertaken to determine state-dependent patterns of neuronal activity in the brainstem based upon the expression of the protein Fos. In addition, double labeling immunohistochemical studies were carried out to detect neurons that expressed Fos as well as choline acetyltransferase, tyrosine hydroxylase or GABA. During NREM, only a few Fos immunoreactive cells were present in different regions of the brainstem; however, a discrete cluster of Fos+ neurons was observed in the caudolateral peribrachial region (CLPB). The number of the Fos+ neurons in the CLPB during NREM was significantly greater (67.9 ± 10.9, P < 0.0001) compared to QW (8.0 ± 6.7), AW (5.2 ± 4.2) or REM-carbachol (8.0 ± 4.7). In addition, there was a positive correlation (R = 0.93) between the time the animals spent in NREM and the number of Fos+ neurons in the CLPB. Fos-immunoreactive neurons in the CLPB were neither cholinergic nor catecholaminergic; however about 50% of these neurons were GABAergic. We conclude that a group of GABAergic and unidentified neurons in the CLPB are active during NREM and likely involved in the control of this behavioral state. These data open new avenues for the study of NREM, as well as for the explorations of

  7. LOW-LATITUDE CORONAL HOLES, DECAYING ACTIVE REGIONS, AND GLOBAL CORONAL MAGNETIC STRUCTURE

    SciTech Connect

    Petrie, G. J. D.; Haislmaier, K. J.

    2013-10-01

    We study the relationship between decaying active-region magnetic fields, coronal holes, and the global coronal magnetic structure using Global Oscillations Network Group synoptic magnetograms, Solar TErrestrial RElations Observatory extreme-ultraviolet synoptic maps, and coronal potential-field source-surface models. We analyze 14 decaying regions and associated coronal holes occurring between early 2007 and late 2010, 4 from cycle 23 and 10 from cycle 24. We investigate the relationship between asymmetries in active regions' positive and negative magnetic intensities, asymmetric magnetic decay rates, flux imbalances, global field structure, and coronal hole formation. Whereas new emerging active regions caused changes in the large-scale coronal field, the coronal fields of the 14 decaying active regions only opened under the condition that the global coronal structure remained almost unchanged. This was because the dominant slowly varying, low-order multipoles prevented opposing-polarity fields from opening and the remnant active-region flux preserved the regions' low-order multipole moments long after the regions had decayed. Thus, the polarity of each coronal hole necessarily matched the polar field on the side of the streamer belt where the corresponding active region decayed. For magnetically isolated active regions initially located within the streamer belt, the more intense polarity generally survived to form the hole. For non-isolated regions, flux imbalance and topological asymmetry prompted the opposite to occur in some cases.

  8. Coronal Magnetography of a Simulated Solar Active Region from Microwave Imaging Spectropolarimetry

    NASA Astrophysics Data System (ADS)

    Wang, Zhitao; Gary, Dale E.; Fleishman, Gregory D.; White, Stephen M.

    2015-06-01

    We have simulated the Expanded Owens Valley Solar Array (EOVSA) radio images generated at multiple frequencies from a model solar active region, embedded in a realistic solar disk model, and explored the resulting data cube for different spectral analysis schemes to evaluate the potential for realizing one of EOVSA’s most important scientific goals—coronal magnetography. In this paper, we focus on modeling the gyroresonance and free-free emission from an on-disk solar active region model with realistic complexities in electron density, temperature and magnetic field distribution. We compare the magnetic field parameters extrapolated from the image data cube along each line of sight after folding through the EOVSA instrumental profile with the original (unfolded) parameters used in the model. We find that even the most easily automated, image-based analysis approach (Level-0) provides reasonable quantitative results, although they are affected by systematic effects due to finite sampling in the Fourier (UV) plane. Finally, we note the potential for errors due to misidentified harmonics of the gyrofrequency, and discuss the prospects for applying a more sophisticated spectrally based analysis scheme (Level-1) to resolve the issue in cases where improved UV coverage and spatial resolution are available.

  9. Simplified 2D Bidomain Model of Whole Heart Electrical Activity and ECG Generation

    NASA Astrophysics Data System (ADS)

    Sovilj, Siniša; Magjarević, Ratko; Abed, Amr Al; Lovell, Nigel H.; Dokos, Socrates

    2014-06-01

    The aim of this study was the development of a geometrically simple and highly computationally-efficient two dimensional (2D) biophysical model of whole heart electrical activity, incorporating spontaneous activation of the sinoatrial node (SAN), the specialized conduction system, and realistic surface ECG morphology computed on the torso. The FitzHugh-Nagumo (FHN) equations were incorporated into a bidomain finite element model of cardiac electrical activity, which was comprised of a simplified geometry of the whole heart with the blood cavities, the lungs and the torso as an extracellular volume conductor. To model the ECG, we placed four electrodes on the surface of the torso to simulate three Einthoven leads VI, VII and VIII from the standard 12-lead system. The 2D model was able to reconstruct ECG morphology on the torso from action potentials generated at various regions of the heart, including the sinoatrial node, atria, atrioventricular node, His bundle, bundle branches, Purkinje fibers, and ventricles. Our 2D cardiac model offers a good compromise between computational load and model complexity, and can be used as a first step towards three dimensional (3D) ECG models with more complex, precise and accurate geometry of anatomical structures, to investigate the effect of various cardiac electrophysiological parameters on ECG morphology.

  10. Fibrinogen cleavage by the Streptococcus pyogenes extracellular cysteine protease and generation of antibodies that inhibit enzyme proteolytic activity.

    PubMed

    Matsuka, Y V; Pillai, S; Gubba, S; Musser, J M; Olmsted, S B

    1999-09-01

    The extracellular cysteine protease from Streptococcus pyogenes is a virulence factor that plays a significant role in host-pathogen interaction. Streptococcal protease is expressed as an inactive 40-kDa precursor that is autocatalytically converted into a 28-kDa mature (active) enzyme. Replacement of the single cysteine residue involved in formation of the enzyme active site with serine (C192S mutation) abolished detectable proteolytic activity and eliminated autocatalytic processing of zymogen to the mature form. In the present study, we investigated activity of the wild-type (wt) streptococcal protease toward human fibrinogen and bovine casein. The former is involved in blood coagulation, wound healing, and other aspects of hemostasis. Treatment with streptococcal protease resulted in degradation of the COOH-terminal region of fibrinogen alpha chain, indicating that fibrinogen may serve as an important substrate for this enzyme during the course of human infection. Polyclonal antibodies generated against recombinant 40- and 28-kDa (r40- and r28-kDa) forms of the C192S streptococcal protease mutant exhibited high enzyme-linked immunosorbent assay titers but demonstrated different inhibition activities toward proteolytic action of the wt enzyme. Activity of the wt protease was readily inhibited when the reaction was carried out in the presence of antibodies generated against r28-kDa C192S mutant. Antibodies produced against r40-kDa C192S mutant had no significant effect on proteolysis. These data suggest that the presence of the NH(2)-terminal prosegment prevents generation of functionally active antibodies and indicate that inhibition activity of antibodies most likely depends on their ability to bind the active-site region epitope(s) of the protein. PMID:10456870

  11. Fibrinogen Cleavage by the Streptococcus pyogenes Extracellular Cysteine Protease and Generation of Antibodies That Inhibit Enzyme Proteolytic Activity

    PubMed Central

    Matsuka, Yury V.; Pillai, Subramonia; Gubba, Siddeswar; Musser, James M.; Olmsted, Stephen B.

    1999-01-01

    The extracellular cysteine protease from Streptococcus pyogenes is a virulence factor that plays a significant role in host-pathogen interaction. Streptococcal protease is expressed as an inactive 40-kDa precursor that is autocatalytically converted into a 28-kDa mature (active) enzyme. Replacement of the single cysteine residue involved in formation of the enzyme active site with serine (C192S mutation) abolished detectable proteolytic activity and eliminated autocatalytic processing of zymogen to the mature form. In the present study, we investigated activity of the wild-type (wt) streptococcal protease toward human fibrinogen and bovine casein. The former is involved in blood coagulation, wound healing, and other aspects of hemostasis. Treatment with streptococcal protease resulted in degradation of the COOH-terminal region of fibrinogen α chain, indicating that fibrinogen may serve as an important substrate for this enzyme during the course of human infection. Polyclonal antibodies generated against recombinant 40- and 28-kDa (r40- and r28-kDa) forms of the C192S streptococcal protease mutant exhibited high enzyme-linked immunosorbent assay titers but demonstrated different inhibition activities toward proteolytic action of the wt enzyme. Activity of the wt protease was readily inhibited when the reaction was carried out in the presence of antibodies generated against r28-kDa C192S mutant. Antibodies produced against r40-kDa C192S mutant had no significant effect on proteolysis. These data suggest that the presence of the NH2-terminal prosegment prevents generation of functionally active antibodies and indicate that inhibition activity of antibodies most likely depends on their ability to bind the active-site region epitope(s) of the protein. PMID:10456870

  12. Scientific and Legal Perspectives on Science Generated for Regulatory Activities

    PubMed Central

    Henry, Carol J.; Conrad, James W.

    2008-01-01

    This article originated from a conference that asked “Should scientific work conducted for purposes of advocacy before regulatory agencies or courts be judged by the same standards as science conducted for other purposes?” In the article, which focuses on the regulatory advocacy context, we argue that it can be and should be. First, we describe a set of standards and practices currently being used to judge the quality of scientific research and testing and explain how these standards and practices assist in judging the quality of research and testing regardless of why the work was conducted. These standards and practices include the federal Information Quality Act, federal Good Laboratory Practice standards, peer review, disclosure of funding sources, and transparency in research policies. The more that scientific information meets these standards and practices, the more likely it is to be of high quality, reliable, reproducible, and credible. We then explore legal issues that may be implicated in any effort to create special rules for science conducted specifically for a regulatory proceeding. Federal administrative law does not provide a basis for treating information in a given proceeding differently depending on its source or the reason for which it was generated. To the contrary, this law positively assures that interested persons have the right to offer their technical expertise toward the solution of regulatory problems. Any proposal to subject scientific information generated for the purpose of a regulatory proceeding to more demanding standards than other scientific information considered in that proceeding would clash with this law and would face significant administrative complexities. In a closely related example, the U.S. Environmental Protection Agency considered but abandoned a program to implement standards aimed at “external” information. PMID:18197313

  13. THE 'MAIN SEQUENCE' OF EXPLOSIVE SOLAR ACTIVE REGIONS: DISCOVERY AND INTERPRETATION

    SciTech Connect

    Falconer, David A.; Moore, Ronald L.; Adams, Mitzi; Gary, G. Allen

    2009-08-01

    We examine the location and distribution of the production of coronal mass ejections (CMEs) and major flares by sunspot active regions in the phase space of two whole-active-region magnetic quantities measured from 1897 SOHO/MDI magnetograms. These magnetograms track the evolution of 44 active regions across the central disk of radius 0.5 R {sub Sun}. The two quantities are {sup L}WL{sub SG}, a gauge of the total free energy in an active region's magnetic field, and {sup L}{phi}, a measure of the active region's total magnetic flux. From these data and each active region's history of production of CMEs, X flares, and M flares, we find (1) that CME/flare-productive active regions are concentrated in a straight-line 'main sequence' in (log {sup L}WL{sub SG}, log {sup L}{phi}) space, (2) that main-sequence active regions have nearly their maximum attainable free magnetic energy, and (3) evidence that this arrangement plausibly results from equilibrium between input of free energy to an explosive active region's magnetic field in the chromosphere and corona by contortion of the field via convection in and below the photosphere and loss of free energy via CMEs, flares, and coronal heating, an equilibrium between energy gain and loss that is analogous to that of the main sequence of hydrogen-burning stars in (mass, luminosity) space.

  14. Three-dimensional MHD modeling of vertical kink oscillations in an active region plasma curtain

    NASA Astrophysics Data System (ADS)

    Ofman, L.; Parisi, M.; Srivastava, A. K.

    2015-10-01

    Context. Observations on 2011 August 9 of an X 6.9-class flare in active region (AR) 11263 by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO), were followed by a rare detection of vertical kink oscillations in a large-scale coronal active region plasma curtain in extreme UV coronal lines with periods in the range 8.8-14.9 min. Aims: Our aim is to study the generation and propagation of the magnetohydrodynamic (MHD) oscillations in the plasma curtain taking the realistic 3D magnetic and the density structure of the curtain into account. We also aim to test and improve coronal seismology for a more accurate determination of the magnetic field than with the standard method. Methods: We use the observed morphological and dynamical conditions, as well as plasma properties of the coronal curtain, to initialize a 3D MHD model of the observed vertical and transverse oscillations. To accomplish this, we implemented the impulsively excited velocity pulse mimicking the flare-generated nonlinear fast magnetosonic propagating disturbance interacting obliquely with the curtain. The model is simplified by utilizing an initial dipole magnetic field, isothermal energy equation, and gravitationally stratified density guided by observational parameters. Results: Using the 3D MHD model, we are able to reproduce the details of the vertical oscillations and study the process of their excitation by a nonlinear fast magnetosonic pulse, propagation, and damping, finding agreement with the observations. Conclusions: We estimate the accuracy of simplified slab-based coronal seismology by comparing the determined magnetic field strength to actual values from the 3D MHD modeling results, and demonstrate the importance of taking more realistic magnetic geometry and density for improving coronal seismology into account. A movie associated to Fig. 1 is available in electronic form at http://www.aanda.org

  15. Lightning activity and aerosols in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Proestakis, E.; Kazadzis, S.; Lagouvardos, K.; Kotroni, V.; Kazantzidis, A.

    2016-03-01

    In the framework of this study, the effect of aerosols on lightning activity has been investigated for the first time over the broader Mediterranean Sea. Atmospheric optical depth data retrieved by MODIS on board Aqua satellite and cloud to ground lightning activity data provided by ZEUS network operated by the National Observatory of Athens were analyzed for a time period spanning from 01/01/2005 up to 31/12/2013. The results indicate the importance of aerosols in lightning modulation. The mean aerosol optical depth (AOD) values of the days with lightning activity were found to be higher than the mean seasonal AOD in 90% of the under study domain. Furthermore, the increasing rate of lightning activity with increasing aerosol loading was found to be more pronounced during summertime and for AOD values up to 0.4. Additionally, the spatial analysis showed that the percentage of days with lightning activity during summertime is increasing with increasing AOD. Finally, time series showed similar temporal behavior between AOD seasonal anomalies and days with lightning activity differences. Both the spatial and temporal analysis showed that lightning activity is correlated to AOD, a characteristic consistent for all seasons.

  16. CMOS Active Pixel Sensor Star Tracker with Regional Electronic Shutter

    NASA Technical Reports Server (NTRS)

    Yadid-Pecht, Orly; Pain, Bedabrata; Staller, Craig; Clark, Christopher; Fossum, Eric

    1996-01-01

    The guidance system in a spacecraft determines spacecraft attitude by matching an observed star field to a star catalog....An APS(active pixel sensor)-based system can reduce mass and power consumption and radiation effects compared to a CCD(charge-coupled device)-based system...This paper reports an APS (active pixel sensor) with locally variable times, achieved through individual pixel reset (IPR).

  17. Automatic Tracking of Active Regions and Detection of Solar Flares in Solar EUV Images

    NASA Astrophysics Data System (ADS)

    Caballero, C.; Aranda, M. C.

    2014-05-01

    Solar catalogs are frequently handmade by experts using a manual approach or semi-automated approach. The appearance of new tools is very useful because the work is automated. Nowadays it is impossible to produce solar catalogs using these methods, because of the emergence of new spacecraft that provide a huge amount of information. In this article an automated system for detecting and tracking active regions and solar flares throughout their evolution using the Extreme UV Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) spacecraft is presented. The system is quite complex and consists of different phases: i) acquisition and preprocessing; ii) segmentation of regions of interest; iii) clustering of these regions to form candidate active regions which can become active regions; iv) tracking of active regions; v) detection of solar flares. This article describes all phases, but focuses on the phases of tracking and detection of active regions and solar flares. The system relies on consecutive solar images using a rotation law to track the active regions. Also, graphs of the evolution of a region and solar evolution are presented to detect solar flares. The procedure developed has been tested on 3500 full-disk solar images (corresponding to 35 days) taken from the spacecraft. More than 75 % of the active regions are tracked and more than 85 % of the solar flares are detected.

  18. Relation between Thermal and Magnetic Properties of Active Regions as a Probe of Coronal Heating Mechanisms

    NASA Astrophysics Data System (ADS)

    Yashiro, Seiji; Shibata, Kazunari

    2001-03-01

    We study the relation between thermal and magnetic properties of active regions in the corona observed with the soft X-ray telescope aboard Yohkoh. We derive the mean temperature and pressure of 64 mature active regions using the filter ratio technique, and examine the relationship of region size with temperature and pressure. We find that the temperature T of active regions increases with increasing region size L as T~L0.28, while the pressure P slightly decreases with the region size as P~L-0.16. We confirm the scaling law T~(PL)1/3 for mature active regions found by R. Rosner, W. H. Tucker, & G. S. Vaiana. We examined the magnetic properties of active regions by analyzing 31 active regions observed with the Solar and Heliospheric Observatory/Michelson Doppler Imager and find the following empirical scaling law between thermal and magnetic properties,Uth~Φ1.33,P~B0.78,where Uth, Φ, and B are the total thermal energy content, total magnetic flux, and average magnetic flux density of active regions, respectively. The former is consistent with the results of L. Golub et al., but the latter is not. Implications of our findings for coronal heating mechanisms are discussed.

  19. Deterministic generation of remote entanglement with active quantum feedback

    DOE PAGESBeta

    Martin, Leigh; Motzoi, Felix; Li, Hanhan; Sarovar, Mohan; Whaley, K. Birgitta

    2015-12-10

    We develop and study protocols for deterministic remote entanglement generation using quantum feedback, without relying on an entangling Hamiltonian. In order to formulate the most effective experimentally feasible protocol, we introduce the notion of average-sense locally optimal feedback protocols, which do not require real-time quantum state estimation, a difficult component of real-time quantum feedback control. We use this notion of optimality to construct two protocols that can deterministically create maximal entanglement: a semiclassical feedback protocol for low-efficiency measurements and a quantum feedback protocol for high-efficiency measurements. The latter reduces to direct feedback in the continuous-time limit, whose dynamics can bemore » modeled by a Wiseman-Milburn feedback master equation, which yields an analytic solution in the limit of unit measurement efficiency. Our formalism can smoothly interpolate between continuous-time and discrete-time descriptions of feedback dynamics and we exploit this feature to derive a superior hybrid protocol for arbitrary nonunit measurement efficiency that switches between quantum and semiclassical protocols. Lastly, we show using simulations incorporating experimental imperfections that deterministic entanglement of remote superconducting qubits may be achieved with current technology using the continuous-time feedback protocol alone.« less

  20. Deterministic generation of remote entanglement with active quantum feedback

    SciTech Connect

    Martin, Leigh; Motzoi, Felix; Li, Hanhan; Sarovar, Mohan; Whaley, K. Birgitta

    2015-12-10

    We develop and study protocols for deterministic remote entanglement generation using quantum feedback, without relying on an entangling Hamiltonian. In order to formulate the most effective experimentally feasible protocol, we introduce the notion of average-sense locally optimal feedback protocols, which do not require real-time quantum state estimation, a difficult component of real-time quantum feedback control. We use this notion of optimality to construct two protocols that can deterministically create maximal entanglement: a semiclassical feedback protocol for low-efficiency measurements and a quantum feedback protocol for high-efficiency measurements. The latter reduces to direct feedback in the continuous-time limit, whose dynamics can be modeled by a Wiseman-Milburn feedback master equation, which yields an analytic solution in the limit of unit measurement efficiency. Our formalism can smoothly interpolate between continuous-time and discrete-time descriptions of feedback dynamics and we exploit this feature to derive a superior hybrid protocol for arbitrary nonunit measurement efficiency that switches between quantum and semiclassical protocols. Lastly, we show using simulations incorporating experimental imperfections that deterministic entanglement of remote superconducting qubits may be achieved with current technology using the continuous-time feedback protocol alone.

  1. Impact-generated Hydrothermal Activity at the Chicxulub Crater

    NASA Astrophysics Data System (ADS)

    Kring, D. A.; Zurcher, L.; Abramov, O.

    2007-05-01

    Borehole samples recovered from PEMEX exploration boreholes and an ICDP scientific borehole indicate the Chicxulub impact event generated hydrothermal alteration throughout a large volume of the Maya Block beneath the crater floor and extending across the bulk of the ~180 km diameter crater. The first indications of hydrothermal alteration were observed in the crater discovery samples from the Yucatan-6 borehole and manifest itself in the form of anhydrite and quartz veins. Continuous core from the Yaxcopoil-1 borehole reveal a more complex and temporally extensive alteration sequence: following a brief period at high temperatures, impact- melt-bearing polymict breccias and a thin, underlying unit of impact melt were subjected to metasomatism, producing alkali feldspar, sphene, apatite, and magnetite. As the system continued to cool, smectite-series phyllosilicates appeared. A saline solution was involved. Stable isotopes suggest the fluid was dominated by a basinal brine created mostly from existing groundwater of the Yucatan Peninsula, although contributions from down-welling water also occurred in some parts of the system. Numerical modeling of the hydrothermal system suggests circulation occurred for 1.5 to 2.3 Myr, depending on the permeability of the system. Our understanding of the hydrothermal system, however, is still crude. Additional core recovery projects, particularly into the central melt sheet, are needed to better evaluate the extent and duration of hydrothermal alteration.

  2. Rapid generation of region-specific probes by chromosome microdissection: Application to the identification of chromosomal rearrangements

    SciTech Connect

    Trent, J.M.; Guan, X.Y.; Zang, J.; Meltzer, P.S. )

    1993-01-01

    The authors present results using a novel strategy for chromosome microdissection and direct in vitro amplification of specific chromosomal regions, to identify cryptic chromosome alterations, and to rapidly generate region-specific genomic probes. First, banded chromosomes are microdissected and directly PCR amplified by a procedure which eliminates microchemistry (Meltzer, et al., Nature Genetics, 1:24, 1992). The resulting PCR product can be used for several applications including direct labeling for fluorescent in situ hybridization (FISH) to normal metaphase chromosomes. A second application of this procedure is the extremely rapid generation of chromosome region-specific probes. This approach has been successfully used to determine the derivation of chromosome segments unidentifiable by standard chromosome banding analysis. In selected instances these probes have also been used on interphase nuclei and provides the potential for assessing chromosome abnormalities in a variety of cell lineages. The microdissection probes (which can be generated in <24 hours) have also been utilized in direct library screening and provide the possibility of acquiring a significant number of region-specific probes for any chromosome band. This procedure extends the limits of conventional cytogenetic analysis by providing an extremely rapid source of numerous band-specific probes, and by enabling the direct analysis of essentially any unknown chromosome region.

  3. Modulation by adenine nucleotides of epileptiform activity in the CA3 region of rat hippocampal slices

    PubMed Central

    Ross, F M; Brodie, M J; Stone, T W

    1998-01-01

    Hippocampal slices (450 μm) generate epileptiform bursts of an interictal nature when perfused with a zero magnesium medium containing 4-aminopyridine (50 μM). The effect of adenine nucleotides on this activity was investigated.ATP and adenosine depressed this epileptiform activity in a concentration-dependent manner, with both purines being equipotent at concentrations above 10 μM.Adenosine deaminase 0.2 u ml−1, a concentration that annuls the effect of adenosine (50 μM), did not significantly alter the depression of activity caused by ATP (50 μM).8-Cyclopentyl-1, 3-dimethylxanthine (CPT), an A1 receptor antagonist, enhanced the discharge rate significantly and inhibited the depressant effect of both ATP and adenosine such that the net effect of ATP or adenosine plus CPT was excitatory.Several ATP analogues were also tested: α, β-methyleneATP (α, β-meATP), 2-methylthioATP (2-meSATP) and uridine triphosphate (UTP). Only α, β-meATP (10 μM) produced an increase in the frequency of spontaneous activity which suggests a lack of involvement of P2Y or P2U receptors.Suramin and pyridoxalphosphate-6-azophenyl-2′, 4′-disulphonic acid (PPADS), P2 receptor antagonists, failed to inhibit the depression produced by ATP (50 μM). The excitatory effect of α, β-meATP (10 μM) was inhibited by suramin (50 μM) and PPADS (5 μM).ATP therefore depresses epileptiform activity in this model in a manner which is not consistent with the activation of known P1 or P2 receptors, suggesting the involvement of a xanthine-sensitive nucleotide receptor. The results are also indicative of an excitatory P2X receptor existing in the hippocampal CA3 region. PMID:9484856

  4. Earthquake Model of the Middle East (EMME) Project: Active Fault Database for the Middle East Region

    NASA Astrophysics Data System (ADS)

    Gülen, L.; Wp2 Team

    2010-12-01

    The Earthquake Model of the Middle East (EMME) Project is a regional project of the umbrella GEM (Global Earthquake Model) project (http://www.emme-gem.org/). EMME project region includes Turkey, Georgia, Armenia, Azerbaijan, Syria, Lebanon, Jordan, Iran, Pakistan, and Afghanistan. Both EMME and SHARE projects overlap and Turkey becomes a bridge connecting the two projects. The Middle East region is tectonically and seismically very active part of the Alpine-Himalayan orogenic belt. Many major earthquakes have occurred in this region over the years causing casualties in the millions. The EMME project will use PSHA approach and the existing source models will be revised or modified by the incorporation of newly acquired data. More importantly the most distinguishing aspect of the EMME project from the previous ones will be its dynamic character. This very important characteristic is accomplished by the design of a flexible and scalable database that will permit continuous update, refinement, and analysis. A digital active fault map of the Middle East region is under construction in ArcGIS format. We are developing a database of fault parameters for active faults that are capable of generating earthquakes above a threshold magnitude of Mw≥5.5. Similar to the WGCEP-2007 and UCERF-2 projects, the EMME project database includes information on the geometry and rates of movement of faults in a “Fault Section Database”. The “Fault Section” concept has a physical significance, in that if one or more fault parameters change, a new fault section is defined along a fault zone. So far over 3,000 Fault Sections have been defined and parameterized for the Middle East region. A separate “Paleo-Sites Database” includes information on the timing and amounts of fault displacement for major fault zones. A digital reference library that includes the pdf files of the relevant papers, reports is also being prepared. Another task of the WP-2 of the EMME project is to prepare

  5. Formation of a double-decker magnetic flux rope in the sigmoidal solar active region 11520

    SciTech Connect

    Cheng, X.; Ding, M. D.; Zhang, J.; Guo, Y.; Sun, X. D.; Wang, Y. M.; Kliem, B.; Deng, Y. Y.

    2014-07-10

    In this paper, we address the formation of a magnetic flux rope (MFR) that erupted on 2012 July 12 and caused a strong geomagnetic storm event on July 15. Through analyzing the long-term evolution of the associated active region observed by the Atmospheric Imaging Assembly and the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, it is found that the twisted field of an MFR, indicated by a continuous S-shaped sigmoid, is built up from two groups of sheared arcades near the main polarity inversion line a half day before the eruption. The temperature within the twisted field and sheared arcades is higher than that of the ambient volume, suggesting that magnetic reconnection most likely works there. The driver behind the reconnection is attributed to shearing and converging motions at magnetic footpoints with velocities in the range of 0.1-0.6 km s{sup –1}. The rotation of the preceding sunspot also contributes to the MFR buildup. Extrapolated three-dimensional non-linear force-free field structures further reveal the locations of the reconnection to be in a bald-patch region and in a hyperbolic flux tube. About 2 hr before the eruption, indications of a second MFR in the form of an S-shaped hot channel are seen. It lies above the original MFR that continuously exists and includes a filament. The whole structure thus makes up a stable double-decker MFR system for hours prior to the eruption. Eventually, after entering the domain of instability, the high-lying MFR impulsively erupts to generate a fast coronal mass ejection and X-class flare; while the low-lying MFR remains behind and continuously maintains the sigmoidicity of the active region.

  6. Formation of a Double-decker Magnetic Flux Rope in the Sigmoidal Solar Active Region 11520

    NASA Astrophysics Data System (ADS)

    Cheng, X.; Ding, M. D.; Zhang, J.; Sun, X. D.; Guo, Y.; Wang, Y. M.; Kliem, B.; Deng, Y. Y.

    2014-07-01

    In this paper, we address the formation of a magnetic flux rope (MFR) that erupted on 2012 July 12 and caused a strong geomagnetic storm event on July 15. Through analyzing the long-term evolution of the associated active region observed by the Atmospheric Imaging Assembly and the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, it is found that the twisted field of an MFR, indicated by a continuous S-shaped sigmoid, is built up from two groups of sheared arcades near the main polarity inversion line a half day before the eruption. The temperature within the twisted field and sheared arcades is higher than that of the ambient volume, suggesting that magnetic reconnection most likely works there. The driver behind the reconnection is attributed to shearing and converging motions at magnetic footpoints with velocities in the range of 0.1-0.6 km s-1. The rotation of the preceding sunspot also contributes to the MFR buildup. Extrapolated three-dimensional non-linear force-free field structures further reveal the locations of the reconnection to be in a bald-patch region and in a hyperbolic flux tube. About 2 hr before the eruption, indications of a second MFR in the form of an S-shaped hot channel are seen. It lies above the original MFR that continuously exists and includes a filament. The whole structure thus makes up a stable double-decker MFR system for hours prior to the eruption. Eventually, after entering the domain of instability, the high-lying MFR impulsively erupts to generate a fast coronal mass ejection and X-class flare; while the low-lying MFR remains behind and continuously maintains the sigmoidicity of the active region.

  7. Synthetic Physical Interactions Map Kinetochore-Checkpoint Activation Regions

    PubMed Central

    Ólafsson, Guðjón; Thorpe, Peter H.

    2016-01-01

    The spindle assembly checkpoint (SAC) is a key mechanism to regulate the timing of mitosis and ensure that chromosomes are correctly segregated to daughter cells. The recruitment of the Mad1 and Mad2 proteins to the kinetochore is normally necessary for SAC activation. This recruitment is coordinated by the SAC kinase Mps1, which phosphorylates residues at the kinetochore to facilitate binding of Bub1, Bub3, Mad1, and Mad2. There is evidence that the essential function of Mps1 is to direct recruitment of Mad1/2. To test this model, we have systematically recruited Mad1, Mad2, and Mps1 to most proteins in the yeast kinetochore, and find that, while Mps1 is sufficient for checkpoint activation, recruitment of either Mad1 or Mad2 is not. These data indicate an important role for Mps1 phosphorylation in SAC activation, beyond the direct recruitment of Mad1 and Mad2. PMID:27280788

  8. Synthetic Physical Interactions Map Kinetochore-Checkpoint Activation Regions.

    PubMed

    Ólafsson, Guðjón; Thorpe, Peter H

    2016-01-01

    The spindle assembly checkpoint (SAC) is a key mechanism to regulate the timing of mitosis and ensure that chromosomes are correctly segregated to daughter cells. The recruitment of the Mad1 and Mad2 proteins to the kinetochore is normally necessary for SAC activation. This recruitment is coordinated by the SAC kinase Mps1, which phosphorylates residues at the kinetochore to facilitate binding of Bub1, Bub3, Mad1, and Mad2. There is evidence that the essential function of Mps1 is to direct recruitment of Mad1/2. To test this model, we have systematically recruited Mad1, Mad2, and Mps1 to most proteins in the yeast kinetochore, and find that, while Mps1 is sufficient for checkpoint activation, recruitment of either Mad1 or Mad2 is not. These data indicate an important role for Mps1 phosphorylation in SAC activation, beyond the direct recruitment of Mad1 and Mad2. PMID:27280788

  9. The era of the wandering mind? Twenty-first century research on self-generated mental activity.

    PubMed

    Callard, Felicity; Smallwood, Jonathan; Golchert, Johannes; Margulies, Daniel S

    2013-01-01

    The first decade of the twenty-first century was characterized by renewed scientific interest in self-generated mental activity (activity largely generated by the individual, rather than in direct response to experimenters' instructions or specific external sensory inputs). To understand this renewal of interest, we interrogated the peer-reviewed literature from 2003 to 2012 (i) to explore recent changes in use of terms for self-generated mental activity; (ii) to investigate changes in the topics on which mind wandering research, specifically, focuses; and (iii) to visualize co-citation communities amongst researchers working on self-generated mental activity. Our analyses demonstrated that there has been a dramatic increase in the term "mind wandering" from 2006, and a significant crossing-over of psychological investigations of mind wandering into cognitive neuroscience (particularly in relation to research on the default mode and default mode network). If our article concludes that this might, indeed, be the "era of the wandering mind," it also calls for more explicit reflection to be given by researchers in this field to the terms they use, the topics and brain regions they focus on, and the research literatures that they implicitly foreground or ignore. PMID:24391606

  10. Phytochemical Composition, Antioxidant Activity and HPLC Fingerprinting Profiles of Three Pyrola Species from Different Regions

    PubMed Central

    Wang, Dongmei; He, Fengyuan; Lv, Zhenjiang; Li, Dengwu

    2014-01-01

    The present study was performed to investigate the variation of phytochemical composition, antioxidant activity and High Performance Liquid Chromatography (HPLC) fingerprinting profiles of three Pyrola species. Thirteen samples (eight P. decorata, three P. calliantha and two P. renifolia) were collected from different regions in China. The tannin, hyperoside and quercetin contents of all samples were determined by reverse-phase HPLC and varied within the range 9.77–34.75, 0.34–2.16 and 0.062–0.147 mg/g dry weigh, respectively. Total flavonoid content was evaluated and varied within the range 16.22–37.82 mg/g dry weight. Antioxidant activity was determined by DPPH assay, with IC50 ranging from 7.96 to 50.33 µg/ml, ABTS•+ and FRAP assay, within the range 612.66–1021.05 and 219.64–398.12 µmol equiv. Trolox/g, respectively. These results revealed that there were significant variations in phytochemical profiles and antioxidant activity among all samples. Due to the higher phytochemical content and significant antioxidant activity, P. calliantha was selected as the most valuable species, and the P. calliantha sample from Left banner of Alxa even possessed the strongest antioxidant activity among all the thirteen samples. Futhermore, Emei Mountain was proved to be the most suitable region for producing P. decorata. Moreover, in order to further evaluate the diversities and quality of Pyrola, HPLC fingerprint analysis coupled with hierarchical cluster and discrimination analyses were introduced to establish a simple, rapid and effective method for accurate identification, classification and quality assessment of Pyrola. Thirteen samples were divided into three groups consistent with their morphological classification. Two types of discriminant functions were generated and the ratio of discrimination was 100%. This method can identify different species of Pyrola and the same species from different regions of origin. Also, it can be used to compare and

  11. 50 CFR 216.240 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Active Sonar Training (AFAST) § 216.240 Specified activity and specified geographical region. (a... Navy is only authorized if it occurs incidental to the use of the following mid-frequency active sonar (MFAS) sources, high frequency active sonar (HFAS) sources, explosive sonobuoys, or similar sources,...

  12. 50 CFR 216.240 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Active Sonar Training (AFAST) § 216.240 Specified activity and specified geographical region. (a... Navy is only authorized if it occurs incidental to the use of the following mid-frequency active sonar (MFAS) sources, high frequency active sonar (HFAS) sources, explosive sonobuoys, or similar sources,...

  13. 50 CFR 216.240 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Active Sonar Training (AFAST) § 216.240 Specified activity and specified geographical region. (a... Navy is only authorized if it occurs incidental to the use of the following mid-frequency active sonar (MFAS) sources, high frequency active sonar (HFAS) sources, explosive sonobuoys, or similar sources,...

  14. The Atlantic Canada-New England Region and Environment. A Learning Activity Packet.

    ERIC Educational Resources Information Center

    Maine Univ., Orono. New England - Atlantic Provinces - Quebec Center.

    In this Learning Activity Packet (LAP) students examine the geographic and ecological bases of the Eastern international region. The overall objective of activities is to help students comprehend the man-earth relationship concept. By studying this familiar relevant region students gain geographic knowledge and skills applicable to other areas.…

  15. 76 FR 58533 - Powder River Regional Coal Team Activities; Notice of Public Meeting in Casper, WY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-21

    ... Bureau of Land Management Powder River Regional Coal Team Activities; Notice of Public Meeting in Casper, WY AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Public Meeting. SUMMARY: The Powder... management activities in the Powder River Coal Production Region. DATES: The RCT meeting will begin at 9...

  16. 78 FR 23951 - Powder River Regional Coal Team Activities: Notice of Public Meeting in Casper, Wyoming

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-23

    ... Bureau of Land Management Powder River Regional Coal Team Activities: Notice of Public Meeting in Casper, Wyoming AGENCY: Bureau of Land Management, Interior. ACTION: Notice of public meeting. SUMMARY: The Powder... management activities in the Powder River Coal Production Region. DATES: The RCT meeting will begin at 9...

  17. Diode laser threshold current density and lasing wavelength as functions of active region thickness

    SciTech Connect

    Streifer, W.; Scifres, D.R.; Burnham, R.D.

    1983-03-01

    Based on a simple model of the band-to-band absorption of a diode laser active region, we formulatean expression for modal gain as a function of pumping current. Using this result yields expressions for threshold current density and lasing photon energy which depend on device parameters including active region thickness, laser length, internal losses, facet reflectivity, etc.

  18. Generations.

    PubMed

    Chambers, David W

    2005-01-01

    Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession. PMID:16623137

  19. Study of Quasi-Homologous Coronal Mass Ejections from Super Active Regions in Solar Cycle 23

    NASA Astrophysics Data System (ADS)

    Liu, L.; Wang, Y.; Shen, C.; Liu, R.; Ye, P.; Wang, S.

    2014-12-01

    Coronal Mass Ejections are most severe eruptive phenomenon in the solar atmosphere and are believed as the major energy source of the Near-Earth Space Environment. The study of CMEs is very important for the Space Weather forecast. The active regions , especially super-active regions, containing lots of magnetic free energy, are considered as the most important source regions of CMEs. Knowing why and how may some active regions (ARs) frequently produce CMEs is one of the key questions to deepen our understanding of the mechanisms and processes of energy accumulation and sudden release in ARs as well as improving our capability of space weather prediction. Based on above, we have done two parts of work: the first one is selecting all 37 SARs in the entire 23 solar cycle, using data provided by SOHO/LASCO C2|EIT|MDI, manually determining 285 CMEs produced by those SARs; second, we use the term 'quasi-homologous'to refer to successive CMEs originating from the same ARs within a short interval, analyze the rules of quasi-homologous CMEs' generation. Finally, we got two conclusions. 1. The waiting times of quasi-homologous CMEs have a two-component distribution with a separation at about 18 hours. The first component is a Gaussian-like distribution with a peak at about 7 hours, which indicates a tight physical connection between these quasi-homologous CMEs. The likelihood of occurrences of two or more CMEs faster than 1200 km /s from the same AR within 18 hours is about 20%. 2. The correlation analysis among CME waiting times, CME speeds and CME occurrence rates reveals that these quantities are independent to each other, suggesting that the perturbation by preceding CMEs rather than free energy input be the direct cause of quasi-homologous CMEs. The peak waiting time of 7 hours probably characterize the time scale of the growth of instabilities triggered by preceding CMEs. This study uncovers more clues from a statistical perspective for us to understand quasi

  20. Observations of Small-scale IRIS Bombs (Reconnection Events) in an Evolving Active Region

    NASA Astrophysics Data System (ADS)

    Madsen, C. A.; Tian, H.; DeLuca, E. E.

    2015-12-01

    We present the first Interface Region Imaging Spectrograph (IRIS) observations of small-scale bombs evolving with their host active region. Bombs appear most clearly in the IRIS 1330 Å and 1400 Å slit-jaw images as small (~1 arcsec), compact, intense brightenings at transition region temperatures. Their NUV/FUV emission spectra exhibit dramatic line splitting and strong absorption features indicative of bidirectional flows from magnetic reconnection embedded deep within the cool lower solar atmosphere. The bombs may contribute significantly to the heating of the solar atmosphere in active regions; however, it's unclear how prevalent the bombs are throughout the lifetime of an active region. Using a semi-automated detection method, we locate bombs within AR 11850 over the course of four observations from 06:00 UT on September 25, 2013 until 11:30 UT the next day. The active region is first observed in an emerging phase and rapidly grows into a mature active region with well-developed sunspots. The bomb occurrence rate drops dramatically as the active region fully emerges. We also find that the bombs fall into two distinct populations: one appears largely during active region emergence and contains a majority of the bombs, while the other population is present regardless of active region age. The first population of bombs is typically found embedded in the low-lying loops prominent in the young active region. Furthermore, we use Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) line-of-sight magnetograms to show that the bombs associated with the first population occur at the boundaries between the upward and downward flux of small, isolated bipolar regions. These regions dissipate as the active region emerges and reconfigures its magnetic field into two large network patches of upward and downward flux with a clear inversion line. The second, smaller population of bombs usually occurs far from the active region loop structures in the plage and

  1. Next-Generation Sequencing of Apoptotic DNA Breakpoints Reveals Association with Actively Transcribed Genes and Gene Translocations

    PubMed Central

    Fullwood, Melissa J.; Lee, Joanne; Lin, Lifang; Li, Guoliang; Huss, Mikael; Ng, Patrick; Sung, Wing-Kin; Shenolikar, Shirish

    2011-01-01

    DNA fragmentation is a well-recognized hallmark of apoptosis. However, the precise DNA sequences cleaved during apoptosis triggered by distinct mechanisms remain unclear. We used next-generation sequencing of DNA fragments generated in Actinomycin D-treated human HL-60 leukemic cells to generate a high-throughput, global map of apoptotic DNA breakpoints. These data highlighted that DNA breaks are non-random and show a significant association with active genes and open chromatin regions. We noted that transcription factor binding sites were also enriched within a fraction of the apoptotic breakpoints. Interestingly, extensive apoptotic cleavage was noted within genes that are frequently translocated in human cancers. We speculate that the non-random fragmentation of DNA during apoptosis may contribute to gene translocations and the development of human cancers. PMID:22087219

  2. MAG4 Versus Alternative Techniques for Forecasting Active-Region Flare Productivity

    NASA Technical Reports Server (NTRS)

    Falconer, David A.; Moore, Ronald L.; Barghouty, Abdulnasser F.; Khazanov, Igor

    2014-01-01

    MAG4 is a technique of forecasting an active region's rate of production of major flares in the coming few days from a free-magnetic-energy proxy. We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region's major-flare productivity from alternative observed aspects of the active region. We demonstrate the method by measuring the difference in performance between the "Present MAG4" technique and each of three alternative techniques, called "McIntosh Active-Region Class," "Total Magnetic Flux," and "Next MAG4." We do this by using (1) the MAG4 database of magnetograms and major-flare histories of sunspot active regions, (2) the NOAA table of the major-flare productivity of each of 60 McIntosh active-region classes of sunspot active regions, and (3) five technique-performance metrics (Heidke Skill Score, True Skill Score, Percent Correct, Probability of Detection, and False Alarm Rate) evaluated from 2000 random two-by-two contingency tables obtained from the databases. We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4).

  3. Generating extreme weather event sets from very large ensembles of regional climate models

    NASA Astrophysics Data System (ADS)

    Massey, Neil; Guillod, Benoit; Otto, Friederike; Allen, Myles; Jones, Richard; Hall, Jim

    2015-04-01

    Generating extreme weather event sets from very large ensembles of regional climate models Neil Massey, Benoit P. Guillod, Friederike E. L. Otto, Myles R. Allen, Richard Jones, Jim W. Hall Environmental Change Institute, University of Oxford, Oxford, UK Extreme events can have large impacts on societies and are therefore being increasingly studied. In particular, climate change is expected to impact the frequency and intensity of these events. However, a major limitation when investigating extreme weather events is that, by definition, only few events are present in observations. A way to overcome this issue it to use large ensembles of model simulations. Using the volunteer distributed computing (VDC) infrastructure of weather@home [1], we run a very large number (10'000s) of RCM simulations over the European domain at a resolution of 25km, with an improved land-surface scheme, nested within a free-running GCM. Using VDC allows many thousands of climate model runs to be computed. Using observations for the GCM boundary forcings we can run historical "hindcast" simulations over the past 100 to 150 years. This allows us, due to the chaotic variability of the atmosphere, to ascertain how likely an extreme event was, given the boundary forcings, and to derive synthetic event sets. The events in these sets did not actually occur in the observed record but could have occurred given the boundary forcings, with an associated probability. The event sets contain time-series of fields of meteorological variables that allow impact modellers to assess the loss the event would incur. Projections of events into the future are achieved by modelling projections of the sea-surface temperature (SST) and sea-ice boundary forcings, by combining the variability of the SST in the observed record with a range of warming signals derived from the varying responses of SSTs in the CMIP5 ensemble to elevated greenhouse gas (GHG) emissions in three RCP scenarios. Simulating the future with a

  4. Projecting changes in annual hydropower generation using regional runoff data: An assessment of the United States federal hydropower plants

    SciTech Connect

    Kao, Shih -Chieh; Sale, Michael J.; Ashfaq, Moetasim; Uria Martinez, Rocio; Kaiser, Dale Patrick; Wei, Yaxing; Diffenbaugh, Noah S.

    2014-12-18

    Federal hydropower plants account for approximately half of installed US conventional hydropower capacity, and are an important part of the national renewable energy portfolio. Utilizing the strong linear relationship between the US Geological Survey WaterWatch runoff and annual hydropower generation, a runoff-based assessment approach is introduced in this study to project changes in annual and regional hydropower generation in multiple power marketing areas. Future climate scenarios are developed with a series of global and regional climate models, and the model output is bias-corrected to be consistent with observed data for the recent past. Using this approach, the median decrease in annual generation at federal projects is projected to be less than –2 TWh, with an estimated ensemble uncertainty of ±9 TWh. Although these estimates are similar to the recently observed variability in annual hydropower generation, and may therefore appear to be manageable, significantly seasonal runoff changes are projected and it may pose significant challenges in water systems with higher limits on reservoir storage and operational flexibility. Lastly, future assessments will be improved by incorporating next-generation climate models, by closer examination of extreme events and longer-term change, and by addressing the interactions among hydropower and other water uses.

  5. Projecting changes in annual hydropower generation using regional runoff data: An assessment of the United States federal hydropower plants

    DOE PAGESBeta

    Kao, Shih -Chieh; Sale, Michael J.; Ashfaq, Moetasim; Uria Martinez, Rocio; Kaiser, Dale Patrick; Wei, Yaxing; Diffenbaugh, Noah S.

    2014-12-18

    Federal hydropower plants account for approximately half of installed US conventional hydropower capacity, and are an important part of the national renewable energy portfolio. Utilizing the strong linear relationship between the US Geological Survey WaterWatch runoff and annual hydropower generation, a runoff-based assessment approach is introduced in this study to project changes in annual and regional hydropower generation in multiple power marketing areas. Future climate scenarios are developed with a series of global and regional climate models, and the model output is bias-corrected to be consistent with observed data for the recent past. Using this approach, the median decrease inmore » annual generation at federal projects is projected to be less than –2 TWh, with an estimated ensemble uncertainty of ±9 TWh. Although these estimates are similar to the recently observed variability in annual hydropower generation, and may therefore appear to be manageable, significantly seasonal runoff changes are projected and it may pose significant challenges in water systems with higher limits on reservoir storage and operational flexibility. Lastly, future assessments will be improved by incorporating next-generation climate models, by closer examination of extreme events and longer-term change, and by addressing the interactions among hydropower and other water uses.« less

  6. Atmospheric energetics in regions of intense convective activity

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.

    1977-01-01

    Synoptic-scale budgets of kinetic and total potential energy are computed using 3- and 6-h data at nine times from NASA's fourth Atmospheric Variability Experiment (AVE IV). Two intense squall lines occurred during the period. Energy budgets for areas that enclose regions of intense convection are shown to have systematic changes that relate to the life cycles of the convection. Some of the synoptic-scale energy processes associated with the convection are found to be larger than those observed in the vicinity of mature cyclones. Volumes enclosing intense convection are found to have large values of cross-contour conversion of potential to kinetic energy and large horizontal export of kinetic energy. Although small net vertical transport of kinetic energy is observed, values at individual layers indicate large upward transport. Transfer of kinetic energy from grid to subgrid scales of motion occurs in the volumes. Latent heat release is large in the middle and upper troposphere and is thought to be the cause of the observed cyclic changes in the budget terms. Total potential energy is found to be imported horizontally in the lower half of the atmosphere, transported aloft, and then exported horizontally. Although local changes of kinetic energy and total potential energy are small, interaction between volumes enclosing convection with surrounding larger volumes is quite large.

  7. Leveling the Playing Field: First Generation Korean American Males and School Based Extracurricular Activities

    ERIC Educational Resources Information Center

    Levy, Corey

    2010-01-01

    This study examined the manner in which extracurricular activities impacted the acculturation of first-generation adolescent males. Specifically, the project focused on the influence of organized high school soccer on the development of first-generation adolescent Korean American males. Eight adolescent participants, ranging in age from fourteen…

  8. Flare activity, sunspot motions, and the evolution of vector magnetic fields in Hale region 17244

    NASA Technical Reports Server (NTRS)

    Neidig, Donald F.; Hagyard, Mona J.; Machado, Marcos E.; Smith, Jesse B., Jr.

    1986-01-01

    The magnetic and dynamical circumstances leading to the 1B/M4 flare of November 5, 1980 are studied, and a strong association is found between the buildup of magnetic shear and the onset of flare activity within the active region. The development of shear, as observed directly in vector magnetograms, is consistent in detail with the dynamical history of the active region and identifies the precise location of the optical and hard-X-ray kernels of the flare emission.

  9. Regional trends in radiogenic heat generation in the Precambrian basement of the Western Canadian Basin

    NASA Astrophysics Data System (ADS)

    Jones, F. W.; Majorowicz, J. A.

    Radiogenic heat generation values for 381 basement samples from 229 sites in the western Canadian basin exhibit a lognormal frequency distribution. The mean value = 2.06 (S.D. = 1.22) µWm-3 is larger than the radiogenic heat generation values reported for the shield in the Superior (ca. 1.2 µWm-3, Jessop and Lewis, 1978) and Churchill (ca. 0.7 µWm-3, Drury, 1985) provinces. When equal Log A contour intervals are used to map the basement heat generation, three large zones of relatively high heat generation are found. One coincides with the Peace River Arch basement structure and one with the Athabasca axis (Darnley, 1981). There is no apparent indication of increased heat flow through the Paleozoic formations associated with these two zones. The third zone, in southwestern Saskatchewan, coincides with a high heat flow zone in the Swift Current area. The lack of correlation between heat flow and heat generation in Alberta may be due to the disturbance to the heat flow in the Paleozoic formations by water motion, or may indicate that the heat is from uranium, thorium and potassium isotope enrichment near the basement surface rather than enrichment throughout the entire upper crust.

  10. Colors of active regions on comet 67P

    NASA Astrophysics Data System (ADS)

    Oklay, N.; Vincent, J.-B.; Sierks, H.; Besse, S.; Fornasier, S.; Barucci, M. A.; Lara, L.; Scholten, F.; Preusker, F.; Lazzarin, M.; Pajola, M.; La Forgia, F.

    2015-10-01

    The OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) scientific imager (Keller et al. 2007) is successfully delivering images of comet 67P/Churyumov-Gerasimenko from its both wide angle camera (WAC) and narrow angle camera (NAC) since ESA's spacecraft Rosetta's arrival to the comet. Both cameras are equipped with filters covering the wavelength range of about 200 nm to 1000 nm. The comet nucleus is mapped with different combination of the filters in resolutions up to 15 cm/px. Besides the determination of the surface morphology in great details (Thomas et al. 2015), such high resolution images provided us a mean to unambiguously link some activity in the coma to a series of pits on the nucleus surface (Vincent et al. 2015).

  11. Mutations in RNA Polymerase Bridge Helix and Switch Regions Affect Active-Site Networks and Transcript-Assisted Hydrolysis.

    PubMed

    Zhang, Nan; Schäfer, Jorrit; Sharma, Amit; Rayner, Lucy; Zhang, Xiaodong; Tuma, Roman; Stockley, Peter; Buck, Martin

    2015-11-01

    In bacterial RNA polymerase (RNAP), the bridge helix and switch regions form an intricate network with the catalytic active centre and the main channel. These interactions are important for catalysis, hydrolysis and clamp domain movement. By targeting conserved residues in Escherichia coli RNAP, we are able to show that functions of these regions are differentially required during σ(70)-dependent and the contrasting σ(54)-dependent transcription activations and thus potentially underlie the key mechanistic differences between the two transcription paradigms. We further demonstrate that the transcription factor DksA directly regulates σ(54)-dependent activation both positively and negatively. This finding is consistent with the observed impacts of DksA on σ(70)-dependent promoters. DksA does not seem to significantly affect RNAP binding to a pre-melted promoter DNA but affects extensively activity at the stage of initial RNA synthesis on σ(54)-regulated promoters. Strikingly, removal of the σ(54) Region I is sufficient to invert the action of DksA (from stimulation to inhibition or vice versa) at two test promoters. The RNAP mutants we generated also show a strong propensity to backtrack. These mutants increase the rate of transcript-hydrolysis cleavage to a level comparable to that seen in the Thermus aquaticus RNAP even in the absence of a non-complementary nucleotide. These novel phenotypes imply an important function of the bridge helix and switch regions as an anti-backtracking ratchet and an RNA hydrolysis regulator. PMID:26365052

  12. Mutations in RNA Polymerase Bridge Helix and Switch Regions Affect Active-Site Networks and Transcript-Assisted Hydrolysis

    PubMed Central

    Zhang, Nan; Schäfer, Jorrit; Sharma, Amit; Rayner, Lucy; Zhang, Xiaodong; Tuma, Roman; Stockley, Peter; Buck, Martin

    2015-01-01

    In bacterial RNA polymerase (RNAP), the bridge helix and switch regions form an intricate network with the catalytic active centre and the main channel. These interactions are important for catalysis, hydrolysis and clamp domain movement. By targeting conserved residues in Escherichia coli RNAP, we are able to show that functions of these regions are differentially required during σ70-dependent and the contrasting σ54-dependent transcription activations and thus potentially underlie the key mechanistic differences between the two transcription paradigms. We further demonstrate that the transcription factor DksA directly regulates σ54-dependent activation both positively and negatively. This finding is consistent with the observed impacts of DksA on σ70-dependent promoters. DksA does not seem to significantly affect RNAP binding to a pre-melted promoter DNA but affects extensively activity at the stage of initial RNA synthesis on σ54-regulated promoters. Strikingly, removal of the σ54 Region I is sufficient to invert the action of DksA (from stimulation to inhibition or vice versa) at two test promoters. The RNAP mutants we generated also show a strong propensity to backtrack. These mutants increase the rate of transcript-hydrolysis cleavage to a level comparable to that seen in the Thermus aquaticus RNAP even in the absence of a non-complementary nucleotide. These novel phenotypes imply an important function of the bridge helix and switch regions as an anti-backtracking ratchet and an RNA hydrolysis regulator. PMID:26365052

  13. Enhanced internal gravity wave activity and breaking over the northeastern Pacific-eastern Asian region

    NASA Astrophysics Data System (ADS)

    Šácha, P.; Kuchař, A.; Jacobi, C.; Pišoft, P.

    2015-11-01

    We have found a stratospheric area of anomalously low annual cycle amplitude and specific dynamics in the stratosphere over the northeastern Pacific-eastern Asia coastal region. Using GPS radio occultation density profiles from the Formosat Satellite Mission 3/Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT-3/COSMIC), we have discovered an internal gravity wave (IGW) activity and breaking hotspot in this region. Conditions supporting orographic wave sourcing and propagation were found. Other possible sources of wave activity in this region are listed. The reasons why this particular IGW activity hotspot was not discovered before as well as why the specific dynamics of this region have not been pointed out are discussed together with the weaknesses of using the mean potential energy as a wave activity proxy. Possible consequences of the specific dynamics in this region on the middle atmospheric dynamics and transport are outlined.

  14. An Active Region Model for Capturing Fractal Flow Patterns inUnsaturated Soils: Model Development

    SciTech Connect

    Liu, Hui-Hai; Zhang, R.; Bodvarsson, Gudmundur S.

    2005-06-11

    Preferential flow commonly observed in unsaturated soils allows rapid movement of solute from the soil surface or vadose zone to the groundwater, bypassing a significant volume of unsaturated soil and increasing the risk of groundwater contamination. A variety of evidence indicates that complex preferential patterns observed from fields are fractals. In this study, we developed a relatively simple active region model to incorporate the fractal flow pattern into the continuum approach. In the model, the flow domain is divided into active and inactive regions. Flow occurs preferentially in the active region (characterized by fractals), and inactive region is simply bypassed. A new constitutive relationship (the portion of the active region as a function of saturation) was derived. The validity of the proposed model is demonstrated by the consistency between field observations and the new constitutive relationship.

  15. Developing a Regionally-Based "Next Generation" High School Climate Science Curriculum

    NASA Astrophysics Data System (ADS)

    Bell, M.; Clark, J.; Getty, S. R.; Marks, J.; Hungate, B. A.; Kaufman, D. S.; Coles, R.; Haden, C.; Cooley, N.

    2012-12-01

    Colorado Plateau Carbon Connections is a regionally relevant, culturally responsive, technology-rich high school climate science curriculum for the Colorado Plateau/Four Corners region. Funded by an NSF Climate Change Education Partnership grant, the 10-lesson curriculum supplement is the result of collaboration between Northern Arizona University climate scientists, social scientists and educators and the NASA-funded Biological Sciences Curriculum Study Carbon Connections project. The curriculum includes disciplinary core ideas in Earth Science from A Framework for K-12 Science Education. It integrates cross-cutting relationships and science and engineering practices. Students are introduced to regional and global effects of climate change, and build their understanding of climate science using simulations and climate models. The models are based on authentic data and allow students to explore the roles of carbon dioxide, volcanic forcing, El Niño effects, solar variability, and anthropogenic inputs to the climate system. Students also negate climate misconceptions using climate science, and analyze personal connections to the climate system. They examine their own carbon footprints and propose regionally based solutions for mitigating the effects of climate change. The curriculum was field tested in Spring 2012 with 384 students and ten teachers in seven schools. The evaluation shows strong student engagement and increased knowledge of climate science and solutions. This curriculum also serves as a model for integrating regional issues into climate science education.

  16. VLA observations of solar active regions at 6 and 20 cm

    NASA Technical Reports Server (NTRS)

    Alissandrakis, C. E.; Kundu, M. R.; Shevgaonkar, K. R.

    1991-01-01

    High-resolution observations are presented of two active regions at 6 and 20 cm over a period of 5 days, together with H-alpha and photospheric magnetic fields. The large-scale emission at 20 cm is associated with the H-alpha plage. In one region the strongest source was over the neutral line, near the tip of an active-region filament, which indicates that the emission probably originated in small-scale coronal loops. In the second region the peak of the emission was near a well-developed sunspot. Neither region showed evidence of large-scale loops joining their preceding and following parts. Several other sources were observed at 20 cm; a source associated with an H-alpha plage region crossed by a filament and one associated with a small bipolar region are briefly discussed. The 6-cm emission from a well-developed spot showed clearly the characteristics expected from gyroresonance model computations.

  17. Hi-C Observations of an Active Region Corona, and Investigation of the Underlying Magnetic Structure

    NASA Technical Reports Server (NTRS)

    Tiwari, S. K.; Alexander, C. E.; Winebarger, A.; Moore, R. L.

    2014-01-01

    The solar corona is much hotter (>=10(exp 6) K) than its surface (approx 6000 K), puzzling astrophysicists for several decades. Active region (AR) corona is again hotter than the quiet Sun (QS) corona by a factor of 4-10. The most widely accepted mechanism that could heat the active region corona is the energy release by current dissipation via reconnection of braided magnetic field structure, first proposed by E. N. Parker three decades ago. The first observational evidence for this mechanism has only recently been presented by Cirtain et al. by using High-resolution Coronal Imager (Hi-C) observations of an AR corona at a spatial resolution of 0.2 arcsec, which is required to resolve the coronal loops, and was not available before the rocket flight of Hi-C in July 2012. The Hi-C project is led by NASA/MSFC. In the case of the QS, work done by convection/granulation on the inter-granular feet of the coronal field lines translates into the heat observed in the corona. In the case of the AR, as here, there could be flux emergence, cancellation/submergence, or shear flows generating large stress and tension in coronal field loops which is released as heat in the corona. We are currently investigating the changes taking place in photospheric feet of the magnetic field involved with brightenings in the Hi-C AR corona. For this purpose, we are also using SDO/AIA data of +/- 2 hours around the 5 minutes Hi-C flight. In the present talk, I will first summarize some of the results of the Hi-C observations and then present some results from our recent analysis on what photospheric processes feed the magnetic energy that dissipates into heat in coronal loops.

  18. Regional vulnerability of the hippocampus to repeated motor activity deprivation.

    PubMed

    Faraji, Jamshid; Soltanpour, Nabiollah; Moeeini, Reza; Hosseini, Seyed Abedin; Pakdel, Shiva; Moharrerie, Alireza; Arjang, Kaveh; Soltanpour, Nasrin; Metz, Gerlinde A S

    2016-03-15

    Spontaneous vertical and horizontal exploratory movements are integral components of rodent behavior. Little is known, however, about the structural and functional consequences of restricted spontaneous exploration. Here, we report two experiments to probe whether restriction in vertical activity (rearing) in rats could induce neuro-hormonal and behavioral disturbances. Rearing movements in rats were deprived for 3h/day for 30 consecutive days by placing the animal into a circular tunnel task. Rats temporarily deprived of rearing behavior showed elevated plasma corticosterone levels but no detectable psychological distress and/or anxiety-related behavior within an elevated plus maze. However, rats emitted a greater number of 22-kHz ultrasonic vocalizations and spent significantly more time vocalizing than controls when deprived of their rearing behavior. Despite intact spatial performance within wet- and dry-land spatial tasks, rearing-deprived rats also exhibited a significant alteration in search strategies within both spatial tasks along with reduced volume and neuron number in the hippocampal subregion CA2. These data suggest a new approach to test the importance of free exploratory behavior in endocrine and structural manifestations. The results support a central role of the CA2 in spontaneous exploratory behavior and vulnerability to psychological stress. PMID:26723539

  19. Precision control of eluted activity from a Sr/Rb generator for cardiac positron emission tomography.

    PubMed

    Klein, R; Adler, A; Beanlands, R S; deKemp, R A

    2004-01-01

    A rubidium-82 (/sup 82/Rb) elution system is described for use with clinical positron emission tomography. The system is self-calibrating with 1.4% repeatability, independent of generator activity and elution flow rate. Saline flow is switched between a /sup 82/Sr//sup 82/Rb generator and a bypass line to achieve a constant activity elution of /sup 82/Rb. In the present study, pulse width modulation (PWM) of a solenoid valve is compared to simple threshold control as a means to simulate a proportional valve. A predictive-corrective control algorithm is developed which produces a constant activity elution within the constraints of long feedback delay and short elution time. Accurate constant-activity elutions of 10-70% of the total generator activity were demonstrated using the threshold comparison control. The adaptive-corrective control of the PWM valve provided a substantial improvement in precision of the steady-state output. PMID:17271953

  20. Effects of energetic heavy ions on electromagnetic ion cyclotron wave generation in the plasmapause region

    NASA Technical Reports Server (NTRS)

    Kozyra, J. U.; Cravens, T. E.; Nagy, A. F.; Fontheim, E. G.; Ong, R. S. B.

    1984-01-01

    An expression for electromagnetic ion cyclotron convective growth rates is derived. The derivation of the dispersion relation and convective growth rates in the presence of a multicomponent energetic and cold plasma is presented. The effects that multiple heavy ions in the ring current and cold plasma produce in the growth and propagation characteristics of ion cyclotron waves are explored. Results of growth rate calculations using parameters consistent with conditions in the plasmapause region during the early recovery phase of geomagnetic storms are presented and compared with ground-based and satellite observations of waves in this region. The geophysical implications of the results are discussed.

  1. A note on chromospheric fine structure at active region polarity boundaries.

    NASA Technical Reports Server (NTRS)

    Prata, S. W.

    1971-01-01

    High resolution H-alpha filtergrams from Big Bear Solar Observatory reveal that some filamentary features in active regions have fine structure and hence magnetic field transverse to the gross structure and the zero longitudinal field line. These features are distinct from the usual active region filament, in which fine structure, magnetic field, and filament are all parallel to the zero longitudinal field line. The latter occur on boundaries between regions of weaker fields, while the former occur at boundaries between regions of stronger field.

  2. The Solomon Sea eddy activity from a 1/36° regional model

    NASA Astrophysics Data System (ADS)

    Djath, Bughsin; Babonneix, Antoine; Gourdeau, Lionel; Marin, Frédéric; Verron, Jacques

    2013-04-01

    In the South West Pacific, the Solomon Sea exhibits the highest levels of eddy kinetic energy but relatively little is known about the eddy activity in this region. This Sea is directly influenced by a monsoonal regime and ENSO variability, and occupies a strategical location as the Western Boundary Currents exiting it are known to feed the warm pool and to be the principal sources of the Equatorial UnderCurrent. During their transit in the Solomon Sea, meso-scale eddies are suspected to notably interact and influence these water masses. The goal of this study is to give an exhaustive description of this eddy activity. A dual approach, based both on altimetric data and high resolution modeling, has then been chosen for this purpose. First, an algorithm is applied on nearly 20 years of 1/3° x 1/3° gridded SLA maps (provided by the AVISO project). This allows eddies to be automatically detected and tracked, thus providing some basic eddy properties. The preliminary results show that two main and distinct types of eddies are detected. Eddies in the north-eastern part shows a variability associated with the mean structure, while those in the southern part are associated with generation/propagation processes. However, the resolution of the AVISO dataset is not very well suited to observe fine structures and to match with the numerous islands bordering the Solomon Sea. For this reason, we will confront these observations with the outputs of a 1/36° resolution realistic model of the Solomon Sea. The high resolution numerical model (1/36°) indeed permits to reproduce very fine scale features, such as eddies and filaments. The model is two-way embedded in a 1/12° regional model which is itself one-way embedded in the DRAKKAR 1/12° global model. The NEMO code is used as well as the AGRIF software for model nestings. Validation is realized by comparison with AVISO observations and available in situ data. In preparing the future wide-swath altimetric SWOT mission that is

  3. Active region upflow plasma: its relation to small activity and the solar wind

    NASA Astrophysics Data System (ADS)

    Mandrini, Cristina H.; Culhane, J. Leonard; Cristiani, Germán; Vásquez, Alberto; Van Driel-Gesztelyi, Lidia; Baker, Deborah; Pick, Monique; Demoulin, Pascal; Nuevo, Federico

    Recent studies show that active region (AR) upflowing plasma, observed by the Hinode EUV Imaging Spectrometer (EIS), can gain access to open field lines and be released into the solar wind via magnetic interchange reconnection occurring below the source surface at magnetic null-points in pseudo-streamer configurations. When only one simple bipolar AR is present on the Sun and it is fully covered by the separatrix of a streamer, like AR 10978 on December 2007, it seems unlikely that the upflowing AR plasma could find its way into the slow solar wind. However, signatures of plasma with AR composition at 1 AU that appears to originate from the West of AR 10978 were recently found by Culhane and coworkers. We present a detailed topology analysis of AR 10978 based on a linear force-free magnetic field model at the AR scale, combined with a global PFSS model. This allows us, on one hand, to explain the variations observed in the upflows to the West of the AR as the result of magnetic reconnection at quasi-separatrix layers (QSLs). While at a global scale, we show that reconnection, occurring in at least two main steps, first at QSLs and later at a high-altitude coronal null-point, allows the AR plasma to get around the topological obstacle of the streamer separatrix and be released into the solar wind.

  4. Monitoring small land subsidence phenomena in the Marmara see region by new SAR generation satellite ESA Sentinel 1

    NASA Astrophysics Data System (ADS)

    Cantone, Alessio; Riccardi, Paolo; Pasquali, Paolo; Defilippi, Marco; Peternier, Achille

    2015-04-01

    The Marmara see region is a large and dense urbanized area affected by tectonics deformations due to the presence of the underlying North Anatolia Fault. This area is affected by strong seismic phenomena (Izmith and Duzce earthquake), and by landslide and small surface deformation. The new generation ESA SAR satellites Copernicus Sentinel-1 system TOPS (Terrain Observation with Progressive Scans in azimuth) permit a short acquisition repetition cycle, an extreme large coverage, a high spatial resolution to respect the covered area and a small baseline separation. All of those characteristics suggest an intensive exploitation of these data through the usage of the interferometry technology and in particular the stacking interferometry for the small terrain displacement monitoring. The Sentinel-1 mission is made up of a constellation of two satellites (A and B units) each carrying a C-band SAR sensor. The objective of the S-1 mission is to acquire systematically with a 12-day repeat orbit cycle for each satellite with a small orbital baselines, characteristics particularly suited for interferometry application. In the near future, when both satellites will be active, there will be an acquisition every 6 days, covering the whole area. The first TOPSAR interferogram has been successfully produced, and the SARScape® stacking processing chains (SBAS and PSI) have been update to support this new sensor. The SBAS (Small Baseline) technique seems to be the best candidate for this application relatively to the morphology and large extension of Marmara region. Moreover the new incremental SBAS will permit a velocity map (at about 25 meters spatial resolution) estimation at near real time at each Sentinel-1 acquisition. We are collecting imaging over the Marmara since October 2014 within the framework of European FP7 Marsite project. In February-March 2015 we will have enough acquisition to perform the first SBAS TOPSAR monitoring of this area. The SBAS processing chain has

  5. Regional stochastic generation of streamflows using an ARIMA (1,0,1) process and disaggregation

    USGS Publications Warehouse

    Armbruster, Jeffrey T.

    1979-01-01

    An ARIMA (1,0,1) model was calibrated and used to generate long annual flow sequences at three sites in the Juniata River basin, Pennsylvania. The model preserves the mean, variance, and cross correlations of the observed station data. In addition, it has a desirable blend of both high and low frequency characteristics and therefore is capable of preserving the Hurst coefficient, h. The generated annual flows are disaggregated into monthly sequences using a modification of the Valencia-Schaake model. The low-flow frequency and flow duration characteristics of the generated monthly flows, with length equal to the historical data, compare favorably with the historical data. Once the models were verified, 100-year sequences were generated and analyzed for their low flow characteristics. One-, three- and six- month low-flow frequencies at recurrence intervals greater than 10 years are generally found to be lower than flow computed from the historical flows. A method is proposed for synthesizing flows at ungaged sites. (Kosco-USGS)

  6. A simple simulation approach to generate complex rainfall fields conditioned by elevation: example of the eastern Mediterranean region

    NASA Astrophysics Data System (ADS)

    Oriani, Fabio; Ohana-Levi, Noa; Straubhaar, Julien; Renard, Philippe; Karnieli, Arnon; Mariethoz, Grégoire; Morin, Efrat; Marra, Francesco

    2016-04-01

    Stochastically generating realistic rainfall fields is useful to study the uncertainty related to catchment recharge and its propagation to distributed hydrological models. To this end, it is critical to use weather radar images as training data, being the single most informative source for rainfall spatial heterogeneity. Generating realistic simulations is particularly important in regions like the eastern Mediterranean, where the synoptic conditions can lead to rainfall fields presenting various morphology, anisotropy and non-stationarity. The Direct Sampling (DS) technique [Mariethoz2010] is proposed here as a stochastic generator of spatial daily rainfall fields relying on the simulation of radar imagery. The technique is based on resampling of a training data set (in this case, a stack of radar images) and the generation of similar patterns to the ones found in the data. The strong point of DS, which makes it an attractive simulation approach for rainfall, is its capability to preserve the high-order statistical features present in the training image (e.g., rainfall cell shape, spatial non-stationarity) with minimal parameterization. Moreover, factors influencing rainfall, like elevation, can be used as conditioning variables, without the need of a complex statistical dependence model. A DS setup for radar image simulation is presented and tested for the simulation of daily rainfall fields using a 10-year radar-image record from the central region of Israel. Using a synoptic weather classification to train the model, the algorithm can generate realistic spatial fields for different rainfall types, preserving the variability and the covariance structure of the reference reasonably well. Moreover, the simulation is conditioned using the digital elevation model to preserve the complex relation between rainfall intensity and altitude that is characteristic for this region. [Mariethoz2010] G. Mariethoz, P. Renard, and J. Straubhaar. The direct sampling method to

  7. Magnetic Structure of Sites of Braiding in Hi-C Active Region

    NASA Technical Reports Server (NTRS)

    Tiwari, S. K.; Alexander, C. E.; Winebarger, A.; Moore, R. L.

    2014-01-01

    High-resolution Coronal Imager (Hi-C) observations of an active region (AR) corona, at a spatial resolution of 0.2 arcsec, have offered the first direct evidence of field lines braiding, which could deliver sufficient energy to heat the AR corona by current dissipation via magnetic reconnection, a proposal given by Parker three decades ago. The energy required to heat the corona must be transported from the photosphere along the field lines. The mechanism that drives the energy transport to the corona is not yet fully understood. To investigate simultaneous magnetic and intensity structure in and around the AR in detail, we use SDO/HMI+AIA data of + / - 2 hours around the 5 minute Hi-C flight. In the case of the QS, work done by convection/granulation on the inter-granular feet of the coronal field lines probably translates into the heat observed in the corona. In the case of the AR, as here, there could be flux emergence, cancellation/submergence, or shear flows generating large stress and tension in coronal field loops which is released as heat in the corona. However, to the best of our knowledge, there is no observational evidence available to these processes. We investigate the changes taking place in the photospheric feet of the magnetic field involved with brightenings in the Hi-C AR corona. Using HMI 45s magnetograms of four hours we find that, out of the two Hi-C sub-regions where the braiding of field lines were recently detected, flux emergence takes place in one region and flux cancellation in the other. The field in these sub-regions are highly sheared and have apparent high speed plasma flows at their feet. Therefore, shearing flows plausibly power much of the coronal and transition region heating in these areas of the AR. In addition, the presence of large flux emergence/cancellation strongly suggests that the work done by these processes on the pre-existing field also drives much of the observed heating.

  8. Enzymatic activation of autotaxin by divalent cations without EF-hand loop region involvement.

    PubMed

    Lee, J; Jung, I D; Nam, S W; Clair, T; Jeong, E M; Hong, S Y; Han, J W; Lee, H W; Stracke, M L; Lee, H Y

    2001-07-15

    Autotaxin (ATX) is a recently described member of the nucleotide pyrophosphatase/phosphodiesterase (NPP) family of proteins with potent tumor cell motility-stimulating activity. Like other NPPs, ATX is a glycoprotein with peptide sequences homologous to the catalytic site of bovine intestinal alkaline phosphodiesterase (PDE) and the loop region of an EF-hand motif. The PDE active site of ATX has been associated with the motility-stimulating activity of ATX. In this study, we examined the roles of the EF-hand loop region and of divalent cations on the enzymatic activities of ATX. Ca(2+) or Mg(2+) was each demonstrated to increase the PDE activity of ATX in a concentration-dependent manner, whereas incubation of ATX with chelating agents abolished this activity, indicating a requirement for divalent cations. Non-linear regression analysis of enzyme kinetic data indicated that addition of these divalent cations increases reaction velocity predominantly through an effect on V(max.) Three mutant proteins, Ala(740)-, Ala(742)-, and Ala(751)-ATX, in the EF-hand loop region of ATX had enzymatic activity comparable to that of the wild-type protein. A deletion mutation of the entire loop region resulted in slightly reduced PDE activity but normal motility-stimulating activity. However, the PDE activity of this same deletion mutant remained sensitive to augmentation by cations, strongly implying that cations exert their effect by interactions outside of the EF-hand loop region. PMID:11389881

  9. Virtual industrial water usage and wastewater generation in the Middle East/North African region

    NASA Astrophysics Data System (ADS)

    Sakhel, S. R.; Geissen, S.-U.; Vogelpohl, A.

    2013-01-01

    This study deals with the quantification of volumes of water usage, wastewater generation, virtual water export, and wastewater generation from export for eight export relevant industries present in the Middle East/North Africa (MENA). It shows that about 3400 million m3 of water is used per annum while around 793 million m3 of wastewater is generated from products that are meant for domestic consumption and export. The difference between volumes of water usage and wastewater generation is due to water evaporation or injecting underground (oil wells pressure maintenance). The wastewater volume generated from production represents a population equivalent of 15.5 million in terms of wastewater quantity and 30.4 million in terms of BOD. About 409 million m3 of virtual water flows from MENA to EU27 (resulting from export of eight commodities) which is equivalent to 12.1% of the water usage of those industries and Libya is the largest virtual water exporter (about 87 million m3). Crude oil and refined petroleum products represent about 89% of the total virtual water flow, fertilizers represent around 10% and 1% remaining industries. EU27 poses the greatest indirect pressure on the Kuwaiti hydrological system where the virtual water export represents about 96% of the actual renewable water resources in this country. The Kuwaiti crude oil water use in relation to domestic water withdrawal is about 89% which is highest among MENA countries. Pollution of water bodies, in terms of BOD, due to production is very relevant for crude oil, slaughterhouses, refineries, olive oil, and tanneries while pollution due to export to EU27 is most relevant for crude oil industry and olive oil mills.

  10. Thermal modeling and hydrocarbon generation in an active-margin basin: Taranaki Basin, New Zealand

    SciTech Connect

    Armstrong, P.A.; Chapman, D.S.; Funnell, R.H.; Allis, R.G.; Kamp, P.J.J.

    1996-08-01

    The Taranaki Basin contains the only known commercial hydrocarbon reserves in New Zealand. The hydrocarbons were derived principally from Late Cretaceous and Paleocene-Eocene coals. An average temperature gradient of 29{degrees}C/km characterizes much of the basin, but gradients range geographically from 22 to 33{degrees}C/km. Thermal and hydrocarbon generation histories were simulated for selected wells that characterize the different regions of the basin. Modeling results show that predepositional and syndepositional Mesozoic crustal thickening, erosion, and rifting resulted in high heat flow during the early stages of deposition. The early high heat flow affected only the deepest source rocks, especially where they are thick and were buried to depths greater than 2.5 km prior to 60 Ma; hydrocarbon generation and expulsion may have been as early as the early Paleocene in these areas. For wells in the Western Platform region, most potential source rocks are immature or have just reached expulsion maturity. However, in areas where initial burial was rapid and more than 1 km of Cretaceous-early Tertiary sediments accumulated, generation amounts sufficient for expulsion may have been reached in the last 1 m.y. for much of the source section, and possibly as early as the Eocene for the deepest source rocks. in the southern Taranaki region, temperatures and generation rates were greatest about 5-10 Ma. About 5 Ma, generation rates decreased and expulsion terminated due to cooling related to structural inversion; temperatures generally are too low for significant oil expulsion (less than 120{degrees}C) at present. In the eastern Taranaki region, the combination of tectonic (rapid sedimentation and erosion) and magmatic effects caused variations in burial depths and geothermal gradients that resulted in oil generation and expulsion that were more spatially and temporally variable than in other regions.

  11. SVZ-derived newly generated neurons populate several olfactory and limbic forebrain regions

    PubMed Central

    Shapiro, Lee A.; Ng, Kwan; Zhou, Qun-Yong; Ribak, Charles E.

    2009-01-01

    Neurogenesis persists in several regions of the adult mammalian brain. Although the hippocampus and olfactory bulb are most commonly studied in the context of adult neurogenesis, there is an increasing body of evidence in support of neurogenesis occurring outside of these two regions. The current study expands upon previous data by showing newborn neurons with a mature phenotype are located in several olfactory and limbic structures outside of the hippocampus and olfactory bulb, where we previously described DCX/BrdU immature neurons. Notably, newborn neurons with a mature neuronal phenotype are found in the olfactory tubercles, anterior olfactory nuclei, tenia tecta, islands of Calleja, amygdala and lateral entorhinal cortex. The appearance of newborn neurons with a mature phenotype in these regions suggests that these structures are destinations, and that newborn neurons are not simply passing through these structures. In light of the increasing body of evidence for neurogenesis in these, and other olfactory, limbic and striatal structures, we hypothesize that brain regions displaying adult neurogenesis are functionally linked. PMID:18849007

  12. Plasminogen-Dependent Matriptase Activation Accelerates Plasmin Generation by Differentiating Primary Human Keratinocytes.

    PubMed

    Chen, Ya-Wen; Yin, Shi; Lai, Ying-Jung J; Johnson, Michael D; Lin, Chen-Yong

    2016-06-01

    Pericellular plasmin generation, an important pathophysiological process, can be initiated and accelerated by the autoactivation of the type 2 transmembrane serine protease matriptase and subsequent activation of urokinase plasminogen activator. The link between matriptase and plasminogen was initially thought to be one-directional: from matriptase, through plasminogen activator, to plasminogen. However, in the current study, we now show that primary human keratinocytes that are undergoing calcium-induced differentiation can rapidly activate matriptase in response to serum treatment via a mechanism dependent on intracellular calcium, protein kinase C, and phosphatidylinositol 3-kinases-based signaling. The serum factor, responsible for the induction of matriptase zymogen activation, was shown to be plasminogen. A sub-pM concentration of plasminogen (but not plasmin) acting at the cell surface is sufficient to induce matriptase activation, suggesting high potency and specificity of the induction. After matriptase zymogen activation, a proportion of active matriptase is shed into extracellular milieu and returns to the cell surface to accelerate plasmin generation. The ability of plasminogen to induce matriptase zymogen activation and the subsequent acceleration of plasmin generation by active matriptase reveals a feed-forward mechanism that allows differentiating human keratinocytes to rapidly and robustly activate pericellular proteolysis. PMID:26872599

  13. Identification of a novel ovine LH-beta promoter region, which dramatically enhances its promoter activity.

    PubMed

    Aherrahrou, Redouane; Aherrahrou, Zouhair; Erdmann, Jeanette; Moumni, Mohieddine

    2015-01-01

    The luteinizing hormone beta subunit (LH-beta) gene plays a critical role in reproduction. In order to characterize and analyze the promoter region of LH-beta in sheep, a genomic library was constructed in phage lambda gt 10 and screened. A novel region of 1,224 bp upstream from the targeted LH-beta gene was identified. Blasting this sequence showed a perfect homology for the first 721 bp sequence with an upstream ovine LH-beta sequence in the database. However, the remaining 5'-503 bp showed no sequence matching. DNA from Moroccan breeds was isolated and the whole region was amplified and confirmed by sequencing. To further confirm the promoter activity of this region, an in vitro analysis using a luciferase assay was carried out. An increase in the promoter activity of the whole region was demonstrated compared to the empty vector. More interestingly, the unpublished region significantly enhanced the promoter activity compared to the known region alone. To predict putative transcription factor binding-sites (TFBSs), an in silico analysis was performed using the TFSEARCH program. The region features many TFBSs and contains two palindrome sequences of 17- and 18-bp. Taken together, a novel region was identified and confirmed in sheep which contained a promoter activity rich with binding sites for a putative regulatory element as shown in silico. PMID:26355566

  14. A STATISTICAL STUDY OF CORONAL ACTIVE EVENTS IN THE NORTH POLAR REGION

    SciTech Connect

    Sako, Nobuharu; Shimojo, Masumi; Watanabe, Tetsuya; Sekii, Takashi

    2013-09-20

    In order to study the relationship between characteristics of polar coronal active events and the magnetic environment in which such events take place, we analyze 526 X-ray jets and 1256 transient brightenings in the polar regions and in regions around the equatorial limbs. We calculate the occurrence rates of these polar coronal active events as a function of distance from the boundary of coronal holes, and find that most events in the polar quiet regions occur adjacent to and equatorward of the coronal hole boundaries, while events in the polar coronal holes occur uniformly within them. Based primarily on the background intensity, we define three categories of regions that produce activity: polar coronal holes, coronal hole boundary regions, and polar quiet regions. We then investigate the properties of the events produced in these regions. We find no significant differences in their characteristics, for example, length and lifetime, but there are differences in the occurrence rates. The mean occurrence rate of X-ray jets around the boundaries of coronal holes is higher than that in the polar quiet regions, equatorial quiet regions, and polar coronal holes. Furthermore, the mean occurrence rate of transient brightenings is also higher in these regions. We make comparison with the occurrence rates of emerging and canceling magnetic fields in the photosphere reported in previous studies, and find that they do not agree with the occurrence rates of transient brightenings found in this study.

  15. Differential activation of protein kinase A in various regions of myocardium during sepsis.

    PubMed

    Hsu, C; Yang, S L; Hsu, S P; Hsu, H K; Liu, M S

    1997-08-01

    Changes in the activities of protein kinase A (PKA) (cAMP-dependent protein kinase) in various regions of rat myocardium during different cardiodynamic phases of sepsis were studied in an attempt to understand the pathophysiology of cardiac dysfunction during sepsis. Sepsis was induced by cecal ligation and puncture (CLP). Experiments were divided into three groups: control, early sepsis, and late sepsis. Early and late sepsis refers to those animals sacrificed at 9 and 18 hr, respectively, after CLP. Cardiac PKA was extracted and partially purified by acid precipitation, ammonium sulfate fractionation, and DEAE-cellulose chromatography. PKA was eluted from DEAE-cellulose column with a linear NaCl gradient. Two types of PKA, Type I (eluted at low ionic strength) and Type II (eluted at high ionic strength), were collected, and their activities were determined based on the rate of incorporation of [gamma-32P]ATP into histone. Under physiological conditions, Type I PKA activities were unevenly distributed (left atrium > right atrium > pacemaker region > left ventricle > right ventricle > ventricular septum) while Type II PKA activities were evenly distributed among different regions of myocardium. During early sepsis, Type I PKA activities remained unchanged while Type II PKA activities were activated by 32 and 70% in right atrium and pacemaker regions, respectively. During late sepsis, Type I PKA activities were stimulated by 228% in ventricular septum while Type II PKA activities were not affected. These data demonstrate that different PKA activities exist in various regions of the myocardium and that PKA activities were preferentially activated in certain areas during the progression of sepsis. Since PKA plays an important role in the regulation of myocardial function and metabolism, the activation of PKA in different regions of myocardial during different stages of sepsis may contribute to the altered cardiac function during the progression of sepsis. PMID:9299285

  16. A Curriculum Activities Guide to Electric Power Generation and the Environment.

    ERIC Educational Resources Information Center

    Tully, Randolph R., Jr., Ed.

    This guide was developed by teachers involved in a workshop on "Electric Power Generation and the Environment." Activity topics are: (1) Energy and the Consumer; (2) Energy and Water Pollution; and (3) Energy and Air Pollution. Within these topics, the activities are classified as awareness level, transitional level, or operational level. Each…

  17. Contradictions between the Virtual and Physical High School Classroom: A Third-Generation Activity Theory Perspective

    ERIC Educational Resources Information Center

    Murphy, Elizabeth; Manzanares, Maria A. Rodriguez

    2008-01-01

    This paper uses a third-generation Activity Theory perspective to gain insight into the contradictions between the activity systems of the physical and virtual high school classroom from the perspective of teachers who had transitioned from one system to the other. Data collection relied on semi-structured interviews conducted with e-teachers as…

  18. An Evaluation of a Wide Range of Job-Generating Activities for Rural Counties.

    ERIC Educational Resources Information Center

    Finsterbusch, Kurt; And Others

    1992-01-01

    Examines the job-generating activities in 15 rural counties in Maryland through 175 interviews and field work. Those ranking high included industrial park development, economic development activities, and tourism. Special financial arrangements for relocating and new businesses also received high marks. Includes 48 references. (JOW)

  19. Exploring Preferences of Mentoring Activities among Generational Groups of Registered Nurses in Florida

    ERIC Educational Resources Information Center

    Posey-Goodwin, Patricia Ann

    2013-01-01

    The purpose of this study was to explore differences in perceptions of mentoring activities from four generations of registered nurses in Florida, using the Alleman Mentoring Activities Questionnaire ® (AMAQ ®). Statistical procedures of analysis of variance (ANOVA) were employed to explore differences among 65 registered nurses in Florida from…

  20. High-throughput generation of an activation-tagged mutant library for functional genomic analyses in tobacco.

    PubMed

    Liu, Feng; Gong, Daping; Zhang, Qian; Wang, Dawei; Cui, Mengmeng; Zhang, Zhiguo; Liu, Guanshan; Wu, Jinxia; Wang, Yuanying

    2015-03-01

    Tobacco (Nicotiana tabacum L.) is an ideal model system for molecular biological and genetic studies. In this study, activation tagging was used to generate approximately 100,000 transgenic tobacco plants. Southern blot analysis indicated that there were 1.6 T-DNA inserts per line on average in our transformed population. The phenotypes observed include abnormalities in leaf and flower morphology, plant height, flowering time, branching, and fertility. Among 6,000 plants in the T0 generation, 57 displayed obvious phenotypes. Among 4,105 lines in the T1 generation, 311 displayed abnormal phenotypes. Fusion primer and nested integrated PCR was used to identify 963 independent genomic loci of T-DNA insertion sites in 1,257 T1 lines. The distribution of T-DNA insertions was non-uniform and correlated well with the predicted gene density along each chromosome. The insertions were biased toward genic regions and noncoding regions within 5 kb of a gene. Fifteen plants that showed the same phenotype as their parent with a dominant pattern in the T2 generation were chosen randomly to detect the expression levels of genes adjacent to the T-DNA integration sites by semi-quantitative RT-PCR. Fifteen candidate genes were identified. Activation was observed in 7 out of the 15 adjacent genes, including one that was located 13.1 kb away from the enhancer sequence. The activation-tagged population described in this paper will be a highly valuable resource for tobacco functional genomics research using both forward and reverse genetic approaches. PMID:25408504

  1. Human Platelets Utilize Cycloxygenase-1 to Generate Dioxolane A3, a Neutrophil-activating Eicosanoid*

    PubMed Central

    Hinz, Christine; Aldrovandi, Maceler; Uhlson, Charis; Marnett, Lawrence J.; Longhurst, Hilary J.; Warner, Timothy D.; Alam, Saydul; Slatter, David A.; Lauder, Sarah N.; Allen-Redpath, Keith; Collins, Peter W.; Murphy, Robert C.; Thomas, Christopher P.; O'Donnell, Valerie B.

    2016-01-01

    Eicosanoids are important mediators of fever, pain, and inflammation that modulate cell signaling during acute and chronic disease. We show by using lipidomics that thrombin-activated human platelets generate a new type of eicosanoid that both stimulates and primes human neutrophil integrin (Mac-1) expression, in response to formylmethionylleucylphenylalanine. Detailed characterization proposes a dioxolane structure, 8-hydroxy-9,11-dioxolane eicosatetraenoic acid (dioxolane A3, DXA3). The lipid is generated in nanogram amounts by platelets from endogenous arachidonate during physiological activation, with inhibition by aspirin in vitro or in vivo, implicating cyclooxygenase-1 (COX). Pharmacological and genetic studies on human/murine platelets revealed that DXA3 formation requires protease-activated receptors 1 and 4, cytosolic phospholipase A2 (cPLA2), Src tyrosine kinases, p38 MAPK, phospholipase C, and intracellular calcium. From data generated by purified COX isoforms and chemical oxidation, we propose that DXA3 is generated by release of an intermediate from the active site followed by oxygenation at C8. In summary, a new neutrophil-activating platelet-derived lipid generated by COX-1 is presented that can activate or prime human neutrophils, suggesting a role in innate immunity and acute inflammation. PMID:27129261

  2. Human Platelets Utilize Cycloxygenase-1 to Generate Dioxolane A3, a Neutrophil-activating Eicosanoid.

    PubMed

    Hinz, Christine; Aldrovandi, Maceler; Uhlson, Charis; Marnett, Lawrence J; Longhurst, Hilary J; Warner, Timothy D; Alam, Saydul; Slatter, David A; Lauder, Sarah N; Allen-Redpath, Keith; Collins, Peter W; Murphy, Robert C; Thomas, Christopher P; O'Donnell, Valerie B

    2016-06-24

    Eicosanoids are important mediators of fever, pain, and inflammation that modulate cell signaling during acute and chronic disease. We show by using lipidomics that thrombin-activated human platelets generate a new type of eicosanoid that both stimulates and primes human neutrophil integrin (Mac-1) expression, in response to formylmethionylleucylphenylalanine. Detailed characterization proposes a dioxolane structure, 8-hydroxy-9,11-dioxolane eicosatetraenoic acid (dioxolane A3, DXA3). The lipid is generated in nanogram amounts by platelets from endogenous arachidonate during physiological activation, with inhibition by aspirin in vitro or in vivo, implicating cyclooxygenase-1 (COX). Pharmacological and genetic studies on human/murine platelets revealed that DXA3 formation requires protease-activated receptors 1 and 4, cytosolic phospholipase A2 (cPLA2), Src tyrosine kinases, p38 MAPK, phospholipase C, and intracellular calcium. From data generated by purified COX isoforms and chemical oxidation, we propose that DXA3 is generated by release of an intermediate from the active site followed by oxygenation at C8. In summary, a new neutrophil-activating platelet-derived lipid generated by COX-1 is presented that can activate or prime human neutrophils, suggesting a role in innate immunity and acute inflammation. PMID:27129261

  3. Beyond participation: the association between school extracurricular activities and involvement in violence across generations of immigration.

    PubMed

    Jiang, Xin; Peterson, Ruth D

    2012-03-01

    Participation in extracurricular activities is purported to protect the broad spectrum of youth from a host of behavioral risks. Yet, empirical research on the extent to which this assumption holds for involvement in violence by immigrant youth is limited. Thus, using data for 13,236 (51.8% female) adolescents from the National Longitudinal Study of Adolescent Health, this study explores how the relationship between extracurricular activities and youth violence varies by type of extracurricular activity profile (sports alone, non-sports alone, and a combination of sports and non-sports) and by generations of immigration (first, second, and third-plus). The sample is composed of 9.3% (n = 1,233) first-generation youth, 15.7% (n = 2,080) second generation, and 74.9% (n = 9,923) third-plus generation. The results reveal that adolescents from the third-plus generation (i.e., non-immigrant youth) who participate in non-sports alone or sports plus non-sports have lower odds of involvement in violence than adolescents from the same generation who do not participate in extracurricular activities. However, for first- and second-generation adolescents, participation in extracurricular activities is associated with higher rather than lower odds of violence compared to their non-participating counterparts. These findings challenge the viewpoint that participation in mainstream extracurricular activities as afforded by US schools is equally beneficial for all youth. They also call for additional research that explores why immigrant youth are less likely than non-immigrant youth to gain violence-reducing benefits when they participate in extracurricular activities. PMID:22167574

  4. Doppler wavelength shifts of ultraviolet spectral lines in solar active regions

    NASA Technical Reports Server (NTRS)

    Feldman, U.; Doschek, G. A.; Cohen, L.

    1982-01-01

    Doppler shifts are measured for solar UV emission lines formed in the lower transition region of active regions. Doppler shifts in different regions at the same solar location, variations of Doppler shift with position of an active region on the disk, and variations of Doppler shift with time at the same solar location in the same active region were studied. Observations were made with the NRL slit spectrograph on Skylab. Excluding flare and flare-related phenomena, only redshifts are found whose magnitudes correspond to downflow velocities between about 4 and 17 km/s. Shifts are largest for lines formed between about 50,000 and 100,000 K, and are distinctly less for lines formed above 100,000 K. The shifts persist out to the limb, but not above it. There is no obvious change in redshift for lines measured at the same solar location over time intervals of about 20 minutes.

  5. Mapping brain region activity during chewing: a functional magnetic resonance imaging study.

    PubMed

    Onozuka, M; Fujita, M; Watanabe, K; Hirano, Y; Niwa, M; Nishiyama, K; Saito, S

    2002-11-01

    Mastication has been suggested to increase neuronal activities in various regions of the human brain. However, because of technical difficulties, the fine anatomical and physiological regions linked to mastication have not been fully elucidated. Using functional magnetic resonance imaging during cycles of rhythmic gum-chewing and no chewing, we therefore examined the interaction between chewing and brain regional activity in 17 subjects (aged 20-31 years). In all subjects, chewing resulted in a bilateral increase in blood oxygenation level-dependent (BOLD) signals in the sensorimotor cortex, supplementary motor area, insula, thalamus, and cerebellum. In addition, in the first three regions, chewing of moderately hard gum produced stronger BOLD signals than the chewing of hard gum. However, the signal was higher in the cerebellum and not significant in the thalamus, respectively. These results suggest that chewing causes regional increases in brain neuronal activities which are related to biting force. PMID:12407087

  6. The erythropoietin receptor transmembrane region is necessary for activation by the Friend spleen focus-forming virus gp55 glycoprotein.

    PubMed Central

    Zon, L I; Moreau, J F; Koo, J W; Mathey-Prevot, B; D'Andrea, A D

    1992-01-01

    The erythropoietin receptor (EPO-R), a member of the cytokine receptor superfamily, can be activated by binding either erythropoietin (EPO) or gp55, the Friend spleen focus-forming virus glycoprotein. The highly specific interaction between gp55 and EPO-R triggers cell proliferation and thereby causes the first stage of Friend virus-induced erythroleukemia. We have generated functional chimeric receptors containing regions of the EPO-R and the interleukin-3 receptor (AIC2A polypeptide), a related cytokine receptor which does not interact with gp55. All chimeric receptors were expressed at similar levels, had similar binding affinities for EPO, and conferred EPO-dependent cell growth. Only those chimeric receptors which contained the EPO-R transmembrane region were activated by gp55. These results demonstrate that the transmembrane region of the EPO-R is critical for activation by gp55. In addition, analysis of a soluble, secreted EPO-R and cysteine point mutants of the EPO-R show that the extracytoplasmic region of the EPO-R specifically interacts with gp55. Images PMID:1320192

  7. Effect of Gravity Waves Generated in the Monsoon Region on Polar Mesospheric Clouds

    NASA Astrophysics Data System (ADS)

    Thurairajah, B.; Bailey, S. M.; Carstens, J. N.; Siskind, D. E.

    2015-12-01

    Gravity Waves (GWs) play an important role in both the formation and destruction of polar mesospheric clouds. In summer, while vertically propagating GWs induce a residual circulation that cools the summer mesosphere and therefore supports the formation of PMCs, observation and modeling studies have also shown that short period GWs can additionally destroy PMCs. In this study we analyze the effect of non-vertical propagation of GWs on PMCs using temperature data from the SABER instrument on TIMED satellite and PMC occurrence frequency from the CIPS instrument on the AIM satellite. During the 2007 PMC season, time series of GWs over the monsoon region at 50 km and PMCs over the polar region at 84 km have a correlation coefficient of 0.9. SABER GW amplitude and momentum flux over the monsoon region show a poleward tilt with altitude. This slanted structure suggests a poleward, but non-vertical, propagation of GWs facilitated by the easterly winds associated with the monsoon circulation, thus indicating a possible source of high latitude middle atmospheric GWs.

  8. Climate services for energy production: are regional climate models reliable for future solar power generation scenarios?

    NASA Astrophysics Data System (ADS)

    Petitta, Marcello; Castelli, Mariapina; Calmanti, Sandro

    2013-04-01

    In this study we present an analysis of surface solar radiation from Regional Climate Models (RCMs) scenario simulations produced during the ENSEMBLES project in order to understand the relation between changes in atmospheric properties and variation of the energy produced by solar power plants. Several studies have recently pointed out the inability and the scarce accuracy of IPCC models in capturing the past decadal variability of Surface Solar Radiation (SSR) (Wild 2009, Wild et al 2010). Most of these works compare observed and estimated SSR for the last 6-7 decades and show that only half of the models are able to reproduce partially the observed decrease (global dimming) and the increase (global brightening) in SSR which occurred respectively in the time intervals 1950-1980 and 1990-2000. We focus on the Euro-Mediterranean area and we compare the SSR data for the period 1951-2000 in order to assess the error associated to the model ensemble. Furthermore we analyze the XXI century regional ENSEMBLES scenarios in order to quantify potential future changes of SSR. The preliminary results obtained so far confirm the findings of Wild et al. for the period 1950-2000. For the future, the analysis shows a positive linear trend over the Mediterranean region. On the other hand, most of the models predict a negative linear trend over Central Europe. We also discuss future energy strategies considering the variability of energy production from solar panels estimated by probabilistic climate change scenarios.

  9. A new generation of the regional climate model REMO: REMO non-hydrostatic

    NASA Astrophysics Data System (ADS)

    Sieck, Kevin; Raub, Thomas; Marien, Lennart; Buntemeyer, Lars; Jacob, Daniela

    2016-04-01

    The regional climate model REMO is well established and has proofed it's value in regional climate simulations for more than a decade. However, due to the hydrostatic formulation REMO is not able to produce useful regional climate information on scales smaller than ~10 km. The demand for higher resolution data especially in the climate service sector is evident. Often climate change information on urban district or even point level is needed. A previous development of a non-hydrostatic dynamical core for REMO utilizing ideas of Miller and Pearce (1974) and Janjic (2001) has been picked up and implemented into the latest hydrostatic REMO version. One of the advantages of the Janjic formulation is that hydrostatic and non-hydrostatic computations are well separated. This offers a straightforward implementation of the non-hydrostatic calculations into an existing hydrostatic model. Other advantages are the easy quantification of the error done by the hydrostatic approximation and the lower computational costs at lower resolutions by switching of the non-hydrostatic part. We will show results from climate simulations on the EURO-CORDEX domain with and without non-hydrostatic option.

  10. HELIOSEISMOLOGY OF PRE-EMERGING ACTIVE REGIONS. II. AVERAGE EMERGENCE PROPERTIES

    SciTech Connect

    Birch, A. C.; Braun, D. C.; Leka, K. D.; Barnes, G.; Javornik, B.

    2013-01-10

    We report on average subsurface properties of pre-emerging active regions as compared to areas where no active region emergence was detected. Helioseismic holography is applied to samples of the two populations (pre-emergence and without emergence), each sample having over 100 members, which were selected to minimize systematic bias, as described in Leka et al. We find that there are statistically significant signatures (i.e., difference in the means of more than a few standard errors) in the average subsurface flows and the apparent wave speed that precede the formation of an active region. The measurements here rule out spatially extended flows of more than about 15 m s{sup -1} in the top 20 Mm below the photosphere over the course of the day preceding the start of visible emergence. These measurements place strong constraints on models of active region formation.

  11. Force and power generating mechanism(s) in active muscle as revealed from temperature perturbation studies.

    PubMed

    Ranatunga, K W

    2010-10-01

    The basic characteristics of the process of force and power generation in active muscle that have emerged from temperature studies are examined. This is done by reviewing complementary findings from temperature-dependence studies and rapid temperature-jump (T-jump) experiments and from intact and skinned fast mammalian muscle fibres. In isometric muscle, a small T-jump leads to a characteristic rise in force showing that crossbridge force generation is endothermic (heat absorbed) and associated with increased entropy (disorder). The sensitivity of the T-jump force generation to added inorganic phosphate (Pi) indicates that a T-jump enhances an early step in the actomyosin (crossbridge) ATPase cycle before Pi-release. During muscle lengthening when steady force is increased, the T-jump force generation is inhibited. Conversely, during shortening when steady force is decreased, the T-jump force generation is enhanced in a velocity-dependent manner, showing that T-jump force generation is strain sensitive. Within the temperature range of ∼5–35◦C, the temperature dependence of steady active force is sigmoidal both in isometric and in shortening muscle. However, in shortening muscle, the endothermic character of force generation becomes more pronounced with increased velocity and this can, at least partly, account for the marked increase with warming of the mechanical power output of active muscle. PMID:20660565

  12. Entropy Generation and Human Aging: Lifespan Entropy and Effect of Physical Activity Level

    NASA Astrophysics Data System (ADS)

    Silva, Carlos; Annamalai, Kalyan

    2008-06-01

    The first and second laws of thermodynamics were applied to biochemical reactions typical of human metabolism. An open-system model was used for a human body. Energy conservation, availability and entropy balances were performed to obtain the entropy generated for the main food components. Quantitative results for entropy generation were obtained as a function of age using the databases from the U.S. Food and Nutrition Board (FNB) and Centers for Disease Control and Prevention (CDC), which provide energy requirements and food intake composition as a function of age, weight and stature. Numerical integration was performed through human lifespan for different levels of physical activity. Results were presented and analyzed. Entropy generated over the lifespan of average individuals (natural death) was found to be 11,404 kJ/ºK per kg of body mass with a rate of generation three times higher on infants than on the elderly. The entropy generated predicts a life span of 73.78 and 81.61 years for the average U.S. male and female individuals respectively, which are values that closely match the average lifespan from statistics (74.63 and 80.36 years). From the analysis of the effect of different activity levels, it is shown that entropy generated increases with physical activity, suggesting that exercise should be kept to a “healthy minimum” if entropy generation is to be minimized.

  13. Generation, Language, Body Mass Index, and Activity Patterns in Hispanic Children

    PubMed Central

    Taverno, Sharon E.; Rollins, Brandi Y.; Francis, Lori A.

    2010-01-01

    Background The acculturation hypothesis proposes an overall disadvantage in health outcomes for Hispanic immigrants with more time spent living in the U.S., but little is known about how generational status and language may influence Hispanic children’s relative weight and activity patterns. Purpose The association between generation and language was investigated with relative weight (BMI z-scores), physical activity, screen time, and participation in extracurricular activities (e.g., sports, clubs) in a U.S.-based, nationally representative sample of Hispanic children. Methods Participants included 2,012 Hispanic children aged 6–11 years from the cross-sectional, 2003 National Survey of Children’s Health. Children were grouped according to generational status (1st, 2nd or 3rd), and the primary language spoken in the home (English vs non-English). Primary analyses included adjusted logistic and multinomial logistic regression to examine the relationships among variables; all analyses were conducted between 2008 and 2009. Results Compared to 3rd generation, English speakers, 1st and 2nd generation, non-English speakers were over two times more likely to be obese. Moreover, 1st generation, non-English speakers were half as likely to engage in regular physical activity and sports. Both 1st and 2nd generation, non-English speakers were less likely to participate in clubs compared to 2nd and 3rd generation, English speakers. Overall, all non–English speaking groups reported less screen time compared to 3rd generation, English speakers. Conclusions The hypothesis that Hispanics lose their health protection with more time spent in the U.S. was not supported in this sample of Hispanic children. PMID:20117570

  14. Complex active regions as the main source of extreme and large solar proton events

    NASA Astrophysics Data System (ADS)

    Ishkov, V. N.

    2013-12-01

    A study of solar proton sources indicated that solar flare events responsible for ≥2000 pfu proton fluxes mostly occur in complex active regions (CARs), i.e., in transition structures between active regions and activity complexes. Different classes of similar structures and their relation to solar proton events (SPEs) and evolution, depending on the origination conditions, are considered. Arguments in favor of the fact that sunspot groups with extreme dimensions are CARs are presented. An analysis of the flare activity in a CAR resulted in the detection of "physical" boundaries, which separate magnetic structures of the same polarity and are responsible for the independent development of each structure.

  15. ATM increases activation-induced cytidine deaminase activity at downstream S regions during class-switch recombination.

    PubMed

    Khair, Lyne; Guikema, Jeroen E J; Linehan, Erin K; Ucher, Anna J; Leus, Niek G J; Ogilvie, Colin; Lou, Zhenkun; Schrader, Carol E; Stavnezer, Janet

    2014-05-15

    Activation-induced cytidine deaminase (AID) initiates Ab class-switch recombination (CSR) in activated B cells resulting in exchanging the IgH C region and improved Ab effector function. During CSR, AID instigates DNA double-strand break (DSB) formation in switch (S) regions located upstream of C region genes. DSBs are necessary for CSR, but improper regulation of DSBs can lead to chromosomal translocations that can result in B cell lymphoma. The protein kinase ataxia telangiectasia mutated (ATM) is an important proximal regulator of the DNA damage response (DDR), and translocations involving S regions are increased in its absence. ATM phosphorylates H2AX, which recruits other DNA damage response (DDR) proteins, including mediator of DNA damage checkpoint 1 (Mdc1) and p53 binding protein 1 (53BP1), to sites of DNA damage. As these DDR proteins all function to promote repair and recombination of DSBs during CSR, we examined whether mouse splenic B cells deficient in these proteins would show alterations in S region DSBs when undergoing CSR. We find that in atm(-/-) cells Sμ DSBs are increased, whereas DSBs in downstream Sγ regions are decreased. We also find that mutations in the unrearranged Sγ3 segment are reduced in atm(-/-) cells. Our data suggest that ATM increases AID targeting and activity at downstream acceptor S regions during CSR and that in atm(-/-) cells Sμ DSBs accumulate as they lack a recombination partner. PMID:24729610

  16. A statistical study of active regions 1967-1981. [of sun

    NASA Technical Reports Server (NTRS)

    Tang, F.; Howard, R.; Adkins, J. M.

    1984-01-01

    A study is conducted of 15 years of active region data based on the Mount Wilson daily magnetograms in the interval 1967-1981. The analysis revealed the following: (1) The integral number of regions decreases exponentially with increasing region sizes, or N(A) = 4788 exp(-A/175) for the 15 years of data, where A is the area in square degrees and N(A) is the number of active regions with area equal to or greater than A; (2) the average area of active regions varies with the phase of the solar cycle. There are more larger regions during maximum than during minimum. (3) Regions in the north are 10 percent larger on average than those in the south during this interval. This coincides with a similar asymmetry in the total magnetic flux between the hemispheres. (4) Regions of all sizes and magnetic complexities show the same characteristic latitude variation with phase in the solar cycle. The largest regions, however, show a narrower latitude range.

  17. Observations of E region irregularities generated at auroral latitudes by a high-power radio wave

    NASA Technical Reports Server (NTRS)

    Djuth, F. T.; Jost, R. J.; Noble, S. T.; Gordon, W. E.; Stubbe, P.

    1985-01-01

    The initial results of a series of observations made with the high-power HF heating facility near Tromso, Norway are reported. During these experiments, attention was focused on the production of artificial geomagnetic field-aligned irregularities (AFAIs) in the auroral E region by HF waves. A mobile 46.9-MHz radar was used to diagnose the formation of AFAIs having spatial scales of 3.2 across geomagnetic field lines. The dynamic characteristics of the AFAIs are discussed within the context of current theoretical work dealing with the natural production of AFAIs in the ionosphere.

  18. MBE growth of active regions for electrically pumped, cw-operating GaSb-based VCSELs

    NASA Astrophysics Data System (ADS)

    Kashani-Shirazi, K.; Bachmann, A.; Boehm, G.; Ziegler, S.; Amann, M.-C.

    2009-03-01

    Electrically pumped, cw-operating, single-mode GaSb-based VCSELs are attractive light sources for trace-gas sensing systems using tunable diode laser absorption spectroscopy (TDLAS) [A. Vicet, D.A. Yarekha, A. Pérona, Y. Rouillard, S. Gaillard, Spectrochimica Acta Part A 58 (2002) 2405-2412]. Only recently, the first electrically pumped (EP) devices emitting at 2.325 μm in cw-mode at room temperature have been reported [A. Bachmann, T. Lim, K. Kashani-Shirazi, O. Dier, C. Lauer, M.-C. Amann, Electronics Letters 44(3) (2008) 202-203]. The fabrication of these devices employs the molecular beam epitaxy (MBE) growth of GaSb/AlAsSb-distributed Bragg mirrors, a multi-quantum-well active region made of AlGaAsSb/InGaAsSb and an InAsSb/GaSb-buried-tunnel junction. As VCSELs are usually driven under high injection rates, an optimum electrical design of active regions is essential for high-performance devices. In this paper we present an enhanced simulation of current flow in the active region under operation conditions. The calculation includes carrier transport by drift, diffusion and tunneling. We discuss different design criteria and material compositions for active regions. Active regions with various barrier materials were incorporated into edge emitter samples to evaluate their performance. Aluminum-containing barriers show better internal efficiency compared to active regions with GaSb as the barrier material.

  19. Gene-scrambling mutagenesis: generation and analysis of insertional mutations in the alginate regulatory region of Pseudomonas aeruginosa.

    PubMed

    Mohr, C D; Deretic, V

    1990-11-01

    A novel method for random mutagenesis of targeted chromosomal regions in Pseudomona aeruginosa was developed. This method can be used with a cloned DNA fragment of indefinite size that contains a putative gene of interest. Cloned DNA is digested to produce small fragments that are then randomly reassembled into long DNA inserts by using cosmid vectors and lambda packaging reaction. This DNA is then transferred into P. aeruginosa and forced into the chromosome via homologous recombination, producing in a single step a random set of insertional mutants along a desired region of the chromosome. Application of this method to extend the analysis of the alginate regulatory region, using a cloned 6.2-kb fragment with the algR gene and the previously uncharacterized flanking regions, produced several insertional mutations. One mutation was obtained in algR, a known transcriptional regulatory of mucoidy in P. aeruginosa. The null mutation of algR was generated in a mucoid derivative of the standard genetic strain PAO responsive to different environmental factors. This mutation was used to demonstrate that the algR gene product was not essential for the regulation of its promoters. Additional insertions were obtained in regions downstream and upstream of algR. A mutation that did not affect mucoidy was generated in a gene located 1 kb upstream of algR. This gene was transcribed in the direction opposite that of algR transcription and encoded a polypeptide of 47 kDa. Partial nucleotide sequence analysis revealed strong homology of its predicted gene product with the human and yeast argininosuccinate lyases. An insertion downstream of algR produced a strain showing reduced induction of mucoidy in response to growth on nitrate as the nitrogen source. PMID:2121708

  20. Gene-scrambling mutagenesis: generation and analysis of insertional mutations in the alginate regulatory region of Pseudomonas aeruginosa.

    PubMed Central

    Mohr, C D; Deretic, V

    1990-01-01

    A novel method for random mutagenesis of targeted chromosomal regions in Pseudomona aeruginosa was developed. This method can be used with a cloned DNA fragment of indefinite size that contains a putative gene of interest. Cloned DNA is digested to produce small fragments that are then randomly reassembled into long DNA inserts by using cosmid vectors and lambda packaging reaction. This DNA is then transferred into P. aeruginosa and forced into the chromosome via homologous recombination, producing in a single step a random set of insertional mutants along a desired region of the chromosome. Application of this method to extend the analysis of the alginate regulatory region, using a cloned 6.2-kb fragment with the algR gene and the previously uncharacterized flanking regions, produced several insertional mutations. One mutation was obtained in algR, a known transcriptional regulatory of mucoidy in P. aeruginosa. The null mutation of algR was generated in a mucoid derivative of the standard genetic strain PAO responsive to different environmental factors. This mutation was used to demonstrate that the algR gene product was not essential for the regulation of its promoters. Additional insertions were obtained in regions downstream and upstream of algR. A mutation that did not affect mucoidy was generated in a gene located 1 kb upstream of algR. This gene was transcribed in the direction opposite that of algR transcription and encoded a polypeptide of 47 kDa. Partial nucleotide sequence analysis revealed strong homology of its predicted gene product with the human and yeast argininosuccinate lyases. An insertion downstream of algR produced a strain showing reduced induction of mucoidy in response to growth on nitrate as the nitrogen source. Images PMID:2121708

  1. Contributions of Active Regions, Sunspots, Quiet Sun to the Solar UV Spectrum

    NASA Astrophysics Data System (ADS)

    Morrill, J. S.; McMullin, D. R.; Cookson, A.; Chapman, G. A.

    2013-12-01

    During the declining phase of the most recent solar cycle, the full disk solar UV spectrum was measured by several space-based instruments, including the SOLSTICE and SIM instruments on the SORCE satellite and the SUSIM instrument on the UARS satellite. These results show distinctively different behavior and have implications for our understanding of the contributions played by various surface features in producing the disk integrated UV spectrum as well as the impact of solar UV emissions on climate. The primary goal of this study is to determine the impact of regions of increased activity (e.g. plage and sunspots) during the recent solar cycle and how this relates to variability of the solar spectrum. Two important results from this study will be the plage and sunspot UV contrast compared to the quiet as well as the center to limb variability of plage, sunspots, and the quiet sun at UV wavelengths. This study will estimate the solar spectrum by utilizing the recently digitized UV spectral radiance observations of plage, sunspots, the quiet sun made by the S082B spectrograph on Skylab, Ca II K images collected at San Fernando Observatory during the recent solar cycle, and a solar spectral model developed under a previous NASA grant. Once generated, these spectra will be compared to the UV observations produced by the above instruments. An important step in the estimation process involves the calibration of the Skylab data for a valid comparison between model and observed spectra. This will require separate calibration curves for SUSIM and SORCE observations. These will be generated from days of no or minimal activity. The determination of separate calibrations will allow any subtle contributions due to variations in instrument performance to be accounted for in the comparison of model and observed spectra. Also, changes in instrumental behavior over time will be separable from real changes in the solar spectrum which are due to contributions of active solar

  2. Contributions of Active Regions, Sunspots, Quiet Sun to the Solar UV Spectrum

    NASA Astrophysics Data System (ADS)

    Morrill, J. S.; McMullin, D. R.; Cookson, A.; Chapman, G. A.

    2011-12-01

    During the declining phase of the most recent solar cycle, the full disk solar UV spectrum was measured by several space-based instruments, including the SOLSTICE and SIM instruments on the SORCE satellite and the SUSIM instrument on the UARS satellite. These results show distinctively different behavior and have implications for our understanding of the contributions played by various surface features in producing the disk integrated UV spectrum as well as the impact of solar UV emissions on climate. The primary goal of this study is to determine the impact of regions of increased activity (e.g. plage and sunspots) during the recent solar cycle and how this relates to variability of the solar spectrum. Two important results from this study will be the plage and sunspot UV contrast compared to the quiet as well as the center to limb variability of plage, sunspots, and the quiet sun at UV wavelengths. This study will estimate the solar spectrum by utilizing the recently digitized UV spectral radiance observations of plage, sunspots, the quiet sun made by the S082B spectrograph on Skylab, Ca II K images collected at San Fernando Observatory during the recent solar cycle, and a solar spectral model developed under a previous NASA grant. Once generated, these spectra will be compared to the UV observations produced by the above instruments. An important step in the estimation process involves the calibration of the Skylab data for a valid comparison between model and observed spectra. This will require separate calibration curves for SUSIM and SORCE observations. These will be generated from days of no or minimal activity. The determination of separate calibrations will allow any subtle contributions due to variations in instrument performance to be accounted for in the comparison of model and observed spectra. Also, changes in instrumental behavior over time will be separable from real changes in the solar spectrum which are due to contributions of active solar

  3. Southeast Regional Assessment Study: an assessment of the opportunities of solar electric power generation in the Southeastern United States

    SciTech Connect

    1980-07-01

    The objective of this study was to identify and assess opportunities for demonstration and large scale deployment of solar electric facilities in the southeast region and to define the technical, economic, and institutional factors that can contribute to an accelerated use of solar energy for electric power generation. Graphs and tables are presented indicating the solar resource potential, siting opportunities, energy generation and use, and socioeconomic factors of the region by state. Solar electric technologies considered include both central station and dispersed solar electric generating facilities. Central stations studied include solar thermal electric, wind, photovoltaic, ocean thermal gradient, and biomass; dispersed facilities include solar thermal total energy systems, wind, and photovoltaic. The value of solar electric facilities is determined in terms of the value of conventional facilities and the use of conventional fuels which the solar facilities can replace. Suitable cost and risk sharing mechanisms to accelerate the commercialization of solar electric technologies in the Southeast are identified. The major regulatory and legal factors which could impact on the commercialization of solar facilities are reviewed. The most important factors which affect market penetration are reviewed, ways to accelerate the implementation of these technologies are identified, and market entry paths are identified. Conclusions and recommendations are presented. (WHK)

  4. HARPs: Tracked Active Region Patch Data Product from SDO/HMI

    NASA Astrophysics Data System (ADS)

    Turmon, M.; Hoeksema, J. T.; Sun, X.; Bobra, M.

    2012-12-01

    We describe an HMI data product consisting of tracked magnetic features on the scale of solar active regions, abbreviated HARPs (HMI Active Region Patches). The HARP data series has been helpful for subsetting individual active regions, for development of near-real-time (NRT) space weather indices for individual active regions, and for defining closed magnetic structures for computationally-intensive algorithms like vector field disambiguation. The data series builds upon the 720s cadence activity masks, which identify large-scale instantaneously-observed magnetic features. Using these masks as a starting point, large spatially-coherent structures are identified using convolution with a longitudinally-extended kernel on a spherical domain. The resulting set of identified regions is then tracked from image to image. The metric for inter-image association is area of overlap between the best current estimate of AR location, as predicted by temporally extrapolating each currently tracked object, and the set of instantaneously-observed magnetic structures. Once completed tracks have been extracted, they are made into a standardized HARP data series by finding the smallest constant-angular-velocity box, of constant width in latitude and longitude, that encompasses all appearances of the active region. This data product is currently available, in definitive and near-real-time forms, with accompanying region-strength, location, and NOAA-AR metadata, on HMI's Joint Science Operations Center (JSOC) data portal.; HARP outlines for three days (2001 February 14, 15, and 16, 00:00 TAI, flipped N-S, selected from the 12-minute cadence original data product). HARPs are shown in the same color (some colors repeated) with a thin white box surrounding each HARP. HARPs are tracked and associated from image to image. HARPs, such as the yellow one in the images above, need not be connected regions. Merges and splits, such as the light blue region, are accounted for automatically.

  5. On the relationship between photospheric footpoint motions and coronal heating in solar active regions

    SciTech Connect

    Van Ballegooijen, A. A.; Asgari-Targhi, M.; Berger, M. A.

    2014-05-20

    Coronal heating theories can be classified as either direct current (DC) or alternating current (AC) mechanisms, depending on whether the coronal magnetic field responds quasi-statically or dynamically to the photospheric footpoint motions. In this paper we investigate whether photospheric footpoint motions with velocities of 1-2 km s{sup –1} can heat the corona in active regions, and whether the corona responds quasi-statically or dynamically to such motions (DC versus AC heating). We construct three-dimensional magnetohydrodynamic models for the Alfvén waves and quasi-static perturbations generated within a coronal loop. We find that in models where the effects of the lower atmosphere are neglected, the corona responds quasi-statically to the footpoint motions (DC heating), but the energy flux into the corona is too low compared to observational requirements. In more realistic models that include the lower atmosphere, the corona responds more dynamically to the footpoint motions (AC heating) and the predicted heating rates due to Alfvén wave turbulence are sufficient to explain the observed hot loops. The higher heating rates are due to the amplification of Alfvén waves in the lower atmosphere. We conclude that magnetic braiding is a highly dynamic process.

  6. Effect of tidal stream power generation on the region-wide circulation in a shallow sea

    NASA Astrophysics Data System (ADS)

    Shapiro, G. I.

    2010-10-01

    Ocean tides are deemed to become a stable source of renewable energy for the future. Tidal energy has two components, the first is the potential energy due to sea level variations and the second comes from the kinetic energy of the tidal streams. This paper is concerned with the backward effect on the ocean currents by a tidal stream farm located in the open shallow sea. Recent studies in channels with 1-D models have indicated that the power potential is not given purely by the flux of kinetic energy, as has been commonly assumed. In this study, a 3-D ocean circulation model is used to estimate (i) maximum extractable energy at different levels of rated generation capacity of the farm, (ii) changes in the strength of currents due to energy extraction, and (iii) alterations in the pattern of residual currents and pathways of passive tracers. As water flow is influenced both by tidal and non-tidal currents, the model takes into account wind-driven and density-driven currents generated by meteorological forcing. Numerical modelling has been carried out for a hypothetical circular farm located in the Celtic Sea north of Cornwall, an area known for its high level of tidal energy. Modelling results clearly indicate that extracted power does not grow linearly with the increase in the rated capacity of the farm. For the case studies covered in this paper, a 100-fold increase in rated generation capacity of the farm results only in 7-fold increase in extracted power, this loss of efficiency is much greater than was estimated earlier with 1-D models. In case of high rated capacity of the farm, kinetic energy of currents is altered significantly as far as 10-20 km away from the farm. At high levels of extracted energy the currents tend to avoid flowing through the farm, an effect which is not captured with 1-D models. Residual currents are altered as far as a hundred kilometres. The magnitude of changes in the dispersion of tracers is highly sensitive to the location. For

  7. Regional activation within the vastus medialis in stimulated and voluntary contractions.

    PubMed

    Gallina, Alessio; Ivanova, Tanya D; Garland, S Jayne

    2016-08-01

    This study examined the contribution of muscle fiber orientation at different knee angles to regional activation identified with high-density surface electromyography (HDsEMG). Monopolar HDsEMG signals were collected using a grid of 13 × 5 electrodes placed over the vastus medialis (VM). Intramuscular electrical stimulation was used to selectively activate two regions within VM. The distribution of EMG responses to stimulation was obtained by calculating the amplitude of the compound action potential for each channel; the position of the peak amplitude was tracked across knee angles to describe shifts of the active muscle regions under the electrodes. In a separate experiment, regional activation was investigated in 10 knee flexion-extension movements against a fixed resistance. Intramuscular stimulation of different VM regions resulted in clear differences in amplitude distribution along the columns of the electrode grid (P < 0.001); changes in knee angle resulted in consistent shifts along the rows (P < 0.01) and negligible shifts along the columns of the electrode grid. Regional VM activation was identified in dynamic movement, with distal shifts of the EMG distribution in the eccentric phase of the movement (P < 0.05) and at more flexed knee angles (P < 0.05). HDsEMG was used to describe regional activation across the VM that was not attributable to anatomic factors. Changes in muscle fiber orientation associated with knee joint angle mainly influence the amplitude distribution along the fiber direction. Future studies are needed to understand possible functional roles for regional activation within the VM in dynamic tasks. PMID:27365281

  8. Regional activation of rapid onset vasodilatation in mouse skeletal muscle: regulation through α-adrenoreceptors.

    PubMed

    Moore, Alex W; Bearden, Shawn E; Segal, Steven S

    2010-09-01

    Exercise onset entails motor unit recruitment and the initiation of vasodilatation. Dilatation can ascend the arteriolar network to encompass proximal feed arteries but is opposed by sympathetic nerve activity, which promotes vasoconstriction and inhibits ascending vasodilatation through activating α-adrenoreceptors. Whereas contractile activity can antagonize sympathetic vasoconstriction, more subtle aspects of this interaction remain to be defined. We tested the hypothesis that constitutive activation of α-adrenoreceptors governs blood flow distribution within individual muscles. The mouse gluteus maximus muscle (GM) consists of Inferior and Superior regions. Each muscle region is supplied by its own motor nerve and feed artery with an anastomotic arteriole (resting diameter 25 microm) that spans both muscle regions. In anaesthetized male C57BL/6J mice (3-5 months old), the GM was exposed and superfused with physiological saline solution (35 degrees C; pH 7.4). Stimulating the inferior gluteal motor nerve (0.1 ms pulse, 100 Hz for 500 ms) evoked a brief tetanic contraction and produced rapid (<1 s) onset vasodilatation (ROV; diameter change, 10 +/- 1 μm) of the anastomotic arteriole along the active (Inferior) muscle region but not along the inactive (Superior) region (n = 8). In contrast, microiontophoresis of acetylcholine (1 μm micropipette tip, 1 μA, 500 ms) initiated dilatation that travelled along the anastomotic arteriole from the Inferior into the Superior muscle region (diameter change, 5 +/- 2 μm). Topical phentolamine (1 μm) had no effect on resting diameter but this inhibition of α-adrenoreceptors enabled ROV to spread along the anastomotic arteriole into the inactive muscle region (dilatation, 7 +/- 1 μm; P < 0.05), where remote dilatation to acetylcholine then doubled (P < 0.05). These findings indicate that constitutive activation of α-adrenoreceptors in skeletal muscle can restrict the spread of dilatation within microvascular resistance

  9. GaN-based vertical-cavity laser performance improvements using tunnel-junction-cascaded active regions

    SciTech Connect

    Piprek, Joachim

    2014-07-07

    This Letter investigates the output power enhancement achieved by tunnel junction insertion into the InGaN multi-quantum well (MQW) active region of a 410 nm vertical-cavity surface-emitting laser which enables the repeated use of carriers for light generation (carrier recycling). While the number of quantum wells remains unchanged, the tunnel junction eliminates absorption caused by the non-uniform MQW carrier distribution. The thermal resistance drops and the excess bias lead to a surprisingly small rise in self-heating.

  10. Different metabolic activity in placental and reflected regions of the human amniotic membrane.

    PubMed

    Banerjee, Asmita; Weidinger, Adelheid; Hofer, Martin; Steinborn, Ralf; Lindenmair, Andrea; Hennerbichler-Lugscheider, Simone; Eibl, Johann; Redl, Heinz; Kozlov, Andrey V; Wolbank, Susanne

    2015-11-01

    Cells of the human amniotic membrane (hAM) have stem cell characteristics with low immunogenicity and anti-inflammatory properties. While hAM is an excellent source for tissue engineering, so far, its sub-regions have not been taken into account. We show that placental and reflected hAM differ distinctly in morphology and functional activity, as the placental region has significantly higher mitochondrial activity, however significantly less reactive oxygen species. Since mitochondria may participate in processes such as cell rescue, we speculate that amniotic sub-regions may have different potential for tissue regeneration, which may be crucial for clinical applications. PMID:26386652

  11. Effect of subwavelength annular aperture diameter on the nondiffracting region of generated Bessel beams.

    PubMed

    Yu, Yuh-Yan; Lin, Ding-Zheng; Huang, Long-Sun; Lee, Chih-Kung

    2009-02-16

    A subwavelength annular aperture (SAA) made on metallic film and deposited on a glass substrate was fabricated by electron-beam lithography (EBL) and which was followed by a metal lift-off process to generate a long propagation range Bessel beam. We propose tuning the focal length and depth of focus (DOF) by changing the diameter of the SAA. We used finite-difference time domain (FDTD) simulations to verify our experimental data. We found that the position of the Bessel Beam focus spot (i.e. focal length) will be farther away from the SAA plane as the diameter of the SAA increases. In addition, the depth of focus (DOF) which is the length of the Bessel beam non-diffracting area, also increases as the diameter of the SAA expands. PMID:19219175

  12. Arsenic Speciation of Waters from the Aegean Region, Turkey by Hydride Generation: Atomic Absorption Spectrometry.

    PubMed

    Çiftçi, Tülin Deniz; Henden, Emur

    2016-08-01

    Arsenic in drinking water is a serious problem for human health. Since the toxicity of arsenic species As(III) and As(V) is different, it is important to determine the concentrations separately. Therefore, it is necessary to develop an accurate and sensitive method for the speciation of arsenic. It was intended with this work to determine the concentrations of arsenic species in water samples collected from Izmir, Manisa and nearby areas. A batch type hydride generation atomic absorption spectrometer was used. As(V) gave no signal under the optimal measurement conditions of As(III). A certified reference drinking water was analyzed by the method and the results showed excellent agreement with the reported values. The procedure was applied to 34 water samples. Eleven tap water, two spring water, 19 artesian well water and two thermal water samples were analyzed under the optimal conditions. PMID:27236436

  13. NASA Surface-Modeling and Grid-Generation (SM/GG) activities

    NASA Technical Reports Server (NTRS)

    Choo, Yung K.

    1992-01-01

    A NASA Steering Committee was formed to carry out the recommendations from the NASA Workshop on Future Directions in Surface Modeling and Grid Generation. Its function is to communicate and coordinate within NASA the acquisition and distribution of geometry/grid generation software/data, establish geometry data exchange standards, and interface with other government, university, and industry efforts. Two speakers present the committee's activities in viewgraph format.

  14. Fiscal Year 2014 Annual Report on BNLs Next Generation Safeguards Initiative Human Capital Development Activities

    SciTech Connect

    Pepper S. E.

    2014-10-10

    Brookhaven National Laboratory’s (BNL’s) Nonproliferation and National Security Department contributes to the National Nuclear Security Administration Office of Nonproliferation and International Security Next Generation Safeguards Initiative (NGSI) through university engagement, safeguards internships, safeguards courses, professional development, recruitment, and other activities aimed at ensuring the next generation of international safeguards professionals is adequately prepared to support the U.S. safeguards mission. This report is a summary of BNL s work under the NGSI program in Fiscal Year 2014.

  15. Generation of propagating spin waves from regions of increased dynamic demagnetising field near magnetic antidots

    SciTech Connect

    Davies, C. S. Kruglyak, V. V.; Sadovnikov, A. V.; Nikitov, S. A.; Grishin, S. V.; Sharaevskii, Yu. P.

    2015-10-19

    We have used Brillouin Light Scattering and micromagnetic simulations to demonstrate a point-like source of spin waves created by the inherently nonuniform internal magnetic field in the vicinity of an isolated antidot formed in a continuous film of yttrium-iron-garnet. The field nonuniformity ensures that only well-defined regions near the antidot respond in resonance to a continuous excitation of the entire sample with a harmonic microwave field. The resonantly excited parts of the sample then served as reconfigurable sources of spin waves propagating (across the considered sample) in the form of caustic beams. Our findings are relevant to further development of magnonic circuits, in which point-like spin wave stimuli could be required, and as a building block for interpretation of spin wave behavior in magnonic crystals formed by antidot arrays.

  16. Characterization of the blob generation region and blobby transport in a stellarator

    NASA Astrophysics Data System (ADS)

    Fuchert, G.; Birkenmeier, G.; Ramisch, M.; Stroth, U.

    2016-05-01

    Filaments of increased pressure (‘blobs’) in the scrape-off layer of toroidally confined magnetized plasmas are studied in the context of fusion research due to their relevance for confinement and wall safety. Analytical models in simple toroidal magnetic field geometries have proven useful to get a quantitative understanding of blob dynamics in tokamaks. However, their direct applicability to the more complicated stellarator geometry is far less studied. The experiments presented here show that in the stellarator TJ-K blobs are field-aligned structures occurring in scrape-off layer regions of negative mean normal curvature, which is in agreement with common blob models. Furthermore, it is shown that in TJ-K, in accordance with findings from tokamaks, blobs account for a significant fraction of the turbulent scrape-off layer transport of the order of several tens of percent.

  17. Detection of Local/Regional Events in Kuwait Using Next-Generation Detection Algorithms

    SciTech Connect

    Gok, M. Rengin; Al-Jerri, Farra; Dodge, Douglas; Al-Enezi, Abdullah; Hauk, Terri; Mellors, R.

    2014-12-10

    Seismic networks around the world use conventional triggering algorithms to detect seismic signals in order to locate local/regional seismic events. Kuwait National Seismological Network (KNSN) of Kuwait Institute of Scientific Research (KISR) is operating seven broad-band and short-period three-component stations in Kuwait. The network is equipped with Nanometrics digitizers and uses Antelope and Guralp acquisition software for processing and archiving the data. In this study, we selected 10 days of archived hourly-segmented continuous data of five stations (Figure 1) and 250 days of continuous recording at MIB. For the temporary deployment our selection criteria was based on KNSN catalog intensity for the period of time we test the method. An autonomous event detection and clustering framework is employed to test a more complete catalog of this short period of time. The goal is to illustrate the effectiveness of the technique and pursue the framework for longer period of time.

  18. Titin stiffness modifies the force-generating region of muscle sarcomeres.

    PubMed

    Li, Yong; Lang, Patrick; Linke, Wolfgang A

    2016-01-01

    The contractile units of striated muscle, the sarcomeres, comprise the thick (myosin) and thin (actin) filaments mediating active contraction and the titin filaments determining "passive" elasticity. We hypothesized that titin may be more active in muscle contraction by directly modulating thick-filament properties. We used single-myofibril mechanical measurements and atomic force microscopy of individual sarcomeres to quantify the effects of sarcomere strain and titin spring length on both the inter-filament lattice spacing and the lateral stiffness of the actin-myosin overlap zone (A-band). We found that strain reduced the lattice spacing similarly in sarcomeres with stiff (rabbit psoas) or compliant titin (rabbit diaphragm), but increased A-band lateral stiffness much more in psoas than in diaphragm. The strain-induced alterations in A-band stiffness that occur independently of lattice spacing effects may be due to titin stiffness-sensing by A-band proteins. This mechanosensitivity could play a role in the physiologically important phenomenon of length-dependent activation of striated muscle. PMID:27079135

  19. Titin stiffness modifies the force-generating region of muscle sarcomeres

    PubMed Central

    Li, Yong; Lang, Patrick; Linke, Wolfgang A.

    2016-01-01

    The contractile units of striated muscle, the sarcomeres, comprise the thick (myosin) and thin (actin) filaments mediating active contraction and the titin filaments determining “passive” elasticity. We hypothesized that titin may be more active in muscle contraction by directly modulating thick-filament properties. We used single-myofibril mechanical measurements and atomic force microscopy of individual sarcomeres to quantify the effects of sarcomere strain and titin spring length on both the inter-filament lattice spacing and the lateral stiffness of the actin-myosin overlap zone (A-band). We found that strain reduced the lattice spacing similarly in sarcomeres with stiff (rabbit psoas) or compliant titin (rabbit diaphragm), but increased A-band lateral stiffness much more in psoas than in diaphragm. The strain-induced alterations in A-band stiffness that occur independently of lattice spacing effects may be due to titin stiffness-sensing by A-band proteins. This mechanosensitivity could play a role in the physiologically important phenomenon of length-dependent activation of striated muscle. PMID:27079135

  20. Multiwavelength observations of a preflare solar active region using the VLA

    NASA Technical Reports Server (NTRS)

    Kundu, M. R.; Shevgaonkar, R. K.

    1985-01-01

    A preflare active region was studied using the Very Large Array at 2, 6, and 20 cm. At 2 cm the region is composed of two components located in regions of opposite polarity. Both components are preheated prior to the impulsive onset of a flare. However, one component develops new structures during preburst phase, and the burst occurs in this location. It is believed that the new structures represent emerging flux regions which interact with an overlying loop to produce a neutral sheet, which ultimately is responsible for triggering the flare.

  1. G-EVER Activities and the Next-generation Volcanic Hazard Assessment System

    NASA Astrophysics Data System (ADS)

    Takarada, S.

    2013-12-01

    The Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management (G-EVER) is a consortium of Asia-Pacific geohazard research institutes that was established in 2012. G-EVER aims to formulate strategies to reduce the risks of disasters worldwide caused by the occurrence of earthquakes, tsunamis and volcanic eruptions. G-EVER is working on enhancing collaboration, sharing of resources, and making information on the risks of earthquakes and volcanic eruptions freely available and understandable. The 1st G-EVER International Symposium was held in Tsukuba, Japan in March 11, 2013. The 2nd Symposium is scheduled in Sendai, Tohoku Japan, in Oct. 19-20, 2013. Currently, 4 working groups were proposed in the G-EVER Consortium. The next-generation volcano hazard assessment WG is developing a useful system for volcanic eruption prediction, risk assessment, and evacuation at various eruption stages. The assessment system is based on volcanic eruption history datasets, volcanic eruption database, and numerical simulations. Volcanic eruption histories including precursor phenomena leading to major eruptions of active volcanoes are very important for future prediction of volcanic eruptions. A high quality volcanic eruption database, which contains compilations of eruption dates, volumes, and types, is important for the next-generation volcano hazard assessment system. Proposing international standards on how to estimate the volume of volcanic products is important to make a high quality volcanic eruption database. Spatial distribution database of volcanic products (e.g. tephra and pyroclastic flow distributions), encoded into a GIS based database is necessary for more precise area and volume estimation and risk assessments. The volcanic eruption database is developed based on past eruption results, which only represents a subset of possible future scenarios. Therefore, numerical simulations with controlled parameters are needed for more precise volcanic eruption

  2. Air pollution and health implications of regional electricity transfer at generational centre and design of compensation mechanism

    NASA Astrophysics Data System (ADS)

    Relhan, Nemika

    India's electricity generation is primarily from coal. As a result of interconnection of grid and establishment of pithead power plants, there has been increased electricity transfer from one region to the other. This results in imbalance of pollution loads between the communities located in generation vis-a-vis consumption region. There may be some states, which are major power generation centres and hence are facing excessive environmental degradation. On the other hand, electricity importing regions are reaping the benefits without paying proper charges for it because present tariff structure does not include the full externalities in it. The present study investigates the distributional implications in terms of air pollution loads between the electricity generation and consumption regions at the state level. It identifies the major electricity importing and exporting states in India. Next, as a case study, it estimates the health damage as a result of air pollution from thermal power plants (TPPs) located in a critically polluted region that is one of the major generator and exporter of electricity. The methodology used to estimate the health damage is based on impact pathway approach. In this method, air pollution modelling has been performed in order to estimate the gridded Particulate Matter (PM) concentration at various receptor locations in the study domain. The air quality modeling exercise helps to quantify the air pollution concentration in each grid and also apportion the contribution of power plants to the total concentration. The health impacts as a result of PM have been estimated in terms of number of mortality and morbidity cases using Concentration Response Function (CRF's) available in the literature. Mortality has been converted into Years of Life Lost (YOLL) using life expectancy table and age wise death distribution. Morbidity has been estimated in terms of number of cases with respect to various health end points. To convert this health

  3. MAG4 versus alternative techniques for forecasting active region flare productivity

    PubMed Central

    Falconer, David A; Moore, Ronald L; Barghouty, Abdulnasser F; Khazanov, Igor

    2014-01-01

    MAG4 is a technique of forecasting an active region's rate of production of major flares in the coming few days from a free magnetic energy proxy. We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region's major-flare productivity from alternative observed aspects of the active region. We demonstrate the method by measuring the difference in performance between the “Present MAG4” technique and each of three alternative techniques, called “McIntosh Active-Region Class,” “Total Magnetic Flux,” and “Next MAG4.” We do this by using (1) the MAG4 database of magnetograms and major flare histories of sunspot active regions, (2) the NOAA table of the major-flare productivity of each of 60 McIntosh active-region classes of sunspot active regions, and (3) five technique performance metrics (Heidke Skill Score, True Skill Score, Percent Correct, Probability of Detection, and False Alarm Rate) evaluated from 2000 random two-by-two contingency tables obtained from the databases. We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4). Key Points Quantitative comparison of performance of pairs of forecasting techniques Next MAG4 forecasts major flares more accurately than Present MAG4 Present MAG4 forecast outperforms McIntosh AR Class and total magnetic flux PMID:26213517

  4. Summary of DEEP STEAM downhole steam generator development activities. [Kern River and Long Beach field tests

    SciTech Connect

    Donaldson, A.B.; Fox, R.L.; Mulac, A.J.

    1981-01-01

    In this paper the concept and goals of the DOE program, DEEP STEAM, as related to the development of a downhole steam generator for deep heavy oil recovery will be discussed. Additionally, the past, present and future activities of the development program being carried out at Sandia National Laboratories will be discussed. These include evaluation studies, surface testing at Bakersfield, CA, a run-in test at Hobbs, NM, and status of field testing at Long Beach, CA. The Long Beach test includes both a downhole diesel-air generator and a surface diesel-oxygen generator. 7 figures.

  5. Magnetic flux transport of decaying active regions and enhanced magnetic network. [of solar supergranulation

    NASA Technical Reports Server (NTRS)

    Wang, Haimin; Zirin, Harold; Ai, Guoxiang

    1991-01-01

    Several series of coordinated observations on decaying active regions and enhanced magnetic network regions on the sun were carried out jointly at Big Bear Solar Observatory and at the Huairou Solar Observing Station of the Bejing Astronomical Observatory in China. The magnetic field evolution in several regions was followed closely for three to seven days. The magnetic flux transport from the remnants of decayed active regions was studied, along with the evolution and lifetime of the magnetic network which defines the boundaries of supergranules. The magnetic flux transport in an enhanced network region was studied in detail and found to be negative. Also briefly described are some properties of moving magnetic features around a sunspot. Results of all of the above studies are presented.

  6. MAGNETIC FIELD TOPOLOGY AND THE THERMAL STRUCTURE OF THE CORONA OVER SOLAR ACTIVE REGIONS

    SciTech Connect

    Schrijver, Carolus J.; DeRosa, Marc L.; Title, Alan M.

    2010-08-20

    Solar extreme ultraviolet (EUV) images of quiescent active-region coronae are characterized by ensembles of bright 1-2 MK loops that fan out from select locations. We investigate the conditions associated with the formation of these persistent, relatively cool, loop fans within and surrounding the otherwise 3-5 MK coronal environment by combining EUV observations of active regions made with TRACE with global source-surface potential-field models based on the full-sphere photospheric field from the assimilation of magnetograms that are obtained by the Michelson Doppler Imager (MDI) on SOHO. We find that in the selected active regions with largely potential-field configurations these fans are associated with (quasi-)separatrix layers (QSLs) within the strong-field regions of magnetic plage. Based on the empirical evidence, we argue that persistent active-region cool-loop fans are primarily related to the pronounced change in connectivity across a QSL to widely separated clusters of magnetic flux, and confirm earlier work that suggested that neither a change in loop length nor in base field strengths across such topological features are of prime importance to the formation of the cool-loop fans. We discuss the hypothesis that a change in the distribution of coronal heating with height may be involved in the phenomenon of relatively cool coronal loop fans in quiescent active regions.

  7. Rendering Three-Dimensional Solar Coronal Structures of Active Region 8227

    NASA Technical Reports Server (NTRS)

    Gary, G. A.; Alexander, D. A.

    1999-01-01

    Coronal X-ray and EUV synthesized images are constructed of Active Region 8227 (May-June 1996) and are compared with Yohkoh/SXT, SOHO/EIT, and TRACE observations. Using the rendering technique of Gary (1997) and Alexander, Gary, and Thompson (1998), specific geometric and physical models are used to integrated the plasma emission along the line of sight to obtain a rendered image. The specific instrumental profiles are convolved in the integration process as well as specific heating functions. We analyze coronal X-ray and EUV structures by constructing synthesized image and comparison with observations provide test of specific physical models. We investigate how different pressure distributions within the active region loop system affect the emission characteristics and compare the various results with coronal observations. We investigate how the different heating functions in the active region are reflected in the effect of overall structure of the region. Specific heating rates are tested.

  8. Selective optogenetic activation of arcuate kisspeptin neurons generates pulsatile luteinizing hormone secretion

    PubMed Central

    Han, Su Young; McLennan, Timothy; Czieselsky, Katja; Herbison, Allan E.

    2015-01-01

    Normal reproductive functioning in mammals depends upon gonadotropin-releasing hormone (GnRH) neurons generating a pulsatile pattern of gonadotropin secretion. The neural mechanism underlying the episodic release of GnRH is not known, although recent studies have suggested that the kisspeptin neurons located in the arcuate nucleus (ARN) may be involved. In the present experiments we expressed channelrhodopsin (ChR2) in the ARN kisspeptin population to test directly whether synchronous activation of these neurons would generate pulsatile luteinizing hormone (LH) secretion in vivo. Characterization studies showed that this strategy targeted ChR2 to 70% of all ARN kisspeptin neurons and that, in vitro, these neurons were activated by 473-nm blue light with high fidelity up to 30 Hz. In vivo, the optogenetic activation of ARN kisspeptin neurons at 10 and 20 Hz evoked high amplitude, pulse-like increments in LH secretion in anesthetized male mice. Stimulation at 10 Hz for 2 min was sufficient to generate repetitive LH pulses. In diestrous female mice, only 20-Hz activation generated significant increments in LH secretion. In ovariectomized mice, 5-, 10-, and 20-Hz activation of ARN kisspeptin neurons were all found to evoke LH pulses. Part of the sex difference, but not the gonadal steroid dependence, resulted from differential pituitary sensitivity to GnRH. Experiments in kisspeptin receptor-null mice, showed that kisspeptin was the critical neuropeptide underlying the ability of ARN kisspeptin neurons to generate LH pulses. Together these data demonstrate that synchronized activation of the ARN kisspeptin neuronal population generates pulses of LH. PMID:26443858

  9. Activating Photodynamic Therapy in vitro with Cerenkov Radiation Generated from Yttrium-90.

    PubMed

    Hartl, Brad A; Hirschberg, Henry; Marcu, Laura; Cherry, Simon R

    2016-01-01

    The translation of photodynamic therapy (PDT) to the clinical setting has primarily been limited to easily accessible and/or superficial diseases, for which traditional light delivery can be performed noninvasively. Cerenkov radiation, as generated from medically relevant radionuclides, has been suggested as a means to deliver light to deeper tissues noninvasively to overcome this depth limitation. This article investigates the utility of Cerenkov radiation, as generated from the radionuclide yttrium-90, for activating the PDT process using clinically approved aminolevulinic acid at 1.0 mm and also the more efficient porphyrin-based photosensitizer mesotetraphenylporphine with two sulfonate groups on adjacent phenyl rings (TPPS2a) at 1.2 µm. Experiments were conducted with monolayer cultured glioma and breast tumor cell lines. Although aminolevulinic acid proved to be ineffective for generating a therapeutic effect at all but the highest activity levels, TPPS2a produced at least a 20% therapeutic effect at activities ranging from 6 to 60 µCi/well for the C6 glioma cell line. Importantly, these results demonstrate for the first time, to our knowledge, that Cerenkov radiation generated from a radionuclide can be used to activate PDT using clinically relevant photosensitizers. These results therefore provide evidence that it may be possible to generate a phototherapeutic effect in vivo using Cerenkov radiation and clinically relevant photosensitizers. PMID:27481495

  10. Organic geochemistry and petrology of oil source rocks, Carpathian Overthrust region, southeastern Poland - Implications for petroleum generation

    USGS Publications Warehouse

    Kruge, M.A.; Mastalerz, Maria; Solecki, A.; Stankiewicz, B.A.

    1996-01-01

    The organic mailer rich Oligocene Menilite black shales and mudstones are widely distributed in the Carpathian Overthrust region of southeastern Poland and have excellent hydrocarbon generation potential, according to TOC, Rock-Eval, and petrographic data. Extractable organic matter was characterized by an equable distribution of steranes by carbon number, by varying amounts of 28,30-dinor-hopane, 18??(H)-oleanane and by a distinctive group of C24 ring-A degraded triterpanes. The Menilite samples ranged in maturity from pre-generative to mid-oil window levels, with the most mature in the southeastern portion of the study area. Carpathian petroleum samples from Campanian Oligocene sandstone reservoirs were similar in biomarker composition to the Menilite rock extracts. Similarities in aliphatic and aromatic hydrocarbon distributions between petroleum asphaltene and source rock pyrolyzates provided further evidence genetically linking Menilite kerogens with Carpathian oils.

  11. On the generation of the pulsating aurora by the loss cone driven whistler instability in the equatorial region

    SciTech Connect

    Huang, L.; Hawkins, J.G.; Lee, L.C. )

    1990-04-01

    Whistler waves are believed to play an important role in the generation of the pulsating aurora. Calculations in the literature show that either a loss cone or a thermal anisotropy in the hot plasma component of the magnetosphere can lead to the generation of incoherent whistler waves. In this paper, the authors have calculated the characteristics of incoherent whistler mode waves generated along the L = 5 geomagnetic field line, and considered the implications for the pulsating aurora if these waves play an important role in the pulsation mechanism. For the loss cone driven whistler instability, the growth rate along the L = 5 field line is largest just above the ionosphere where the loss cone angle is also large. However, the total amplification factor is actually much larger near the equator due to the more gradual magnetospheric variations and the smaller group velocity in this region. Thus, the largest wave growth from this process is expected in the same location where pitch angle scattering is believed to occur during auroral pulsations. The peak growth rate at the equator occurs at approximately 100 Hz, corresponding to {approximately} 1% of the local electron cyclotron frequency. This frequency is much smaller than the peak growth rate frequency at altitudes nearer to the ionosphere on the L = 5 field line. It is also in contrast to the frequently stated assumption that the whistler instability results in wave generation near the electron cyclotron frequency.

  12. 50 CFR 217.151 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... activity and specified geographical region. (a) Regulations in this subpart apply only to Port Dolphin Energy LLC (Port Dolphin) and those persons it authorizes to conduct activities on its behalf for the... incidental to construction and operation of the Port Dolphin Deepwater Port (Port). (b) The taking of...

  13. 50 CFR 217.151 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... activity and specified geographical region. (a) Regulations in this subpart apply only to Port Dolphin Energy LLC (Port Dolphin) and those persons it authorizes to conduct activities on its behalf for the... incidental to construction and operation of the Port Dolphin Deepwater Port (Port). (b) The taking of...

  14. Hepatitis C virus nonstructural region 5A protein is a potent transcriptional activator.

    PubMed Central

    Kato, N; Lan, K H; Ono-Nita, S K; Shiratori, Y; Omata, M

    1997-01-01

    The hepatitis C virus (HCV) nonstructural region 5A (NS5A) protein, without its 146 amino-terminal amino acids and fused to the DNA-binding domain of GAL4, strongly activates transcription in yeast and human hepatoma cells. Transcriptional activation by the HCV NS5A protein may play a role in viral replication and hepatocarcinogenesis. PMID:9343247

  15. 50 CFR 217.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Operation and Maintenance of the Neptune Liquefied Natural Gas Facility Off Massachusetts § 217.170 Specified activity and specified geographical region. (a) Regulations in this subpart apply only to Neptune LNG LLC (Neptune) and those persons it authorizes to conduct activities on its behalf for the...

  16. 50 CFR 217.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Operation and Maintenance of the Neptune Liquefied Natural Gas Facility Off Massachusetts § 217.170 Specified activity and specified geographical region. (a) Regulations in this subpart apply only to Neptune LNG LLC (Neptune) and those persons it authorizes to conduct activities on its behalf for the...

  17. 50 CFR 217.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Operation and Maintenance of the Neptune Liquefied Natural Gas Facility Off Massachusetts § 217.170 Specified activity and specified geographical region. (a) Regulations in this subpart apply only to Neptune LNG LLC (Neptune) and those persons it authorizes to conduct activities on its behalf for the...

  18. 50 CFR 217.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Operation and Maintenance of the Neptune Liquefied Natural Gas Facility Off Massachusetts § 217.170 Specified activity and specified geographical region. (a) Regulations in this subpart apply only to Neptune LNG LLC (Neptune) and those persons it authorizes to conduct activities on its behalf for the...

  19. Supercontinuum generation using a selectively water-filled photonic crystal fiber for enhancement in the visible spectral region

    NASA Astrophysics Data System (ADS)

    Yoshida, Eiichi; Wada, Akira; Karasawa, Naoki

    2016-07-01

    We generated a supercontinuum from a selectively water-filled photonic crystal fiber (PCF) for enhancement in the visible spectral region using an optical pulse from a Ti:sapphire oscillator at 804 nm. We prepared a 7-cm-long fused silica PCF, where the holes adjacent to the central core were filled with water, using a UV-curable adhesive to close holes selectively before filling holes with water by capillary force. Compared with that of the PCF without water, the group velocity dispersion curve of the selectively water-filled PCF became flatter near 800 nm and the intensity in the visible spectral region of the supercontinuum became higher and more uniform. The spectra simulated using the calculated dispersion properties of the selectively water-filled PCF showed good agreement with the experimental spectra.

  20. Dissipative structures in the F-region of the equatorial ionosphere generated by Rayleigh-Taylor instability

    NASA Astrophysics Data System (ADS)

    Sazonov, S. V.

    1991-12-01

    The nonlinear regime of electrostatic perturbations of the equatorial ionospheric F-region generated by Rayleigh-Taylor instability has been discussed, taking into account conductivity along magnetic field lines. A closed nonlinear equation has been derived in the stationary limit for the polarization electric field potential. It coincides with the Karman equation of an ideal liquid. To solve the equation, the averaged variational Whitham method has been proposed. Some solutions localized along and across the geomagnetic field, B, as well as quasi-periodic solutions in the transverse direction, have been investigated. Nonlinear longitudinal localization of perturbations has been shown to be due to electron-ion collisions.

  1. Drawing as a Generative Activity and Drawing as a Prognostic Activity

    ERIC Educational Resources Information Center

    Schwamborn, Annett; Mayer, Richard E.; Thillmann, Hubertina; Leopold, Claudia; Leutner, Detlev

    2010-01-01

    In this study, 9th-grade students (N = 196) with a mean age of 14.7 years read a scientific text explaining the chemical process of doing laundry with soap and water and then took 3 tests. Students who were instructed to generate drawings during learning scored higher than students who only read on subsequent tests of transfer (d = 0.91),…

  2. Generation of Integration-free and Region-Specific Neural Progenitors from Primate Fibroblasts

    PubMed Central

    Lu, Jianfeng; Liu, Huisheng; Huang, Cindy Tzu-Ling; Chen, Hong; Du, Zhongwei; Liu, Yan; Sherafat, Mohammad Amin; Zhang, Su-Chun

    2013-01-01

    SUMMARY Postnatal and adult human and monkey fibroblasts were infected with Sendai virus containing the Yamanaka factors for 24 hr, then they were cultured in a chemically defined medium containing leukemia inhibitory factor (LIF), transforming growth factor (TGF)-β inhibitor SB431542, and glycogen synthase kinase (GSK)-3β inhibitor CHIR99021 at 39°C for inactivation of the virus. Induced neural progenitor (iNP) colonies appeared as early as day 13 and can be expanded for >20 passages. Under the same defined condition, no induced pluripotent stem cell (iPSC) colonies formed at either 37°Cor 39°C. The iNPs predominantly express hindbrain genes and differentiate into hindbrain neurons, and when caudalized, they produced an enriched population of spinal motor neurons. Following transplantation into the forebrain, the iNP-derived cells retained the hindbrain identity. The ability to generate defined, integration-free iNPs from adult primate fibroblasts under a defined condition with predictable fate choices will facilitate disease modeling and therapeutic development. PMID:23643533

  3. VECSELs emitting at 976nm designed for second harmonic generation in the blue wavelength region

    NASA Astrophysics Data System (ADS)

    Muszalski, Jan; Broda, Artur; Jasik, Agata; Wójcik-Jedlińska, Anna; Trajnerowicz, Artur; Kubacka-Traczyk, Justyna; Sankowskaa, Iwona

    2013-01-01

    Using a Vertical Cavity Surface Emitting Laser (VECSEL) "as-grown" heterostructure we set-up a laser emitting at 488 nm with the output power approaching 20mW. The short wavelength emission was due to the conversion of the 976nm emission by a second harmonic generation process in a type-I lithum triborate (LBO). The V-type external cavity permitted efficient focusing of the laser beam on both the VECSEL heterostructure and the non linear crystal. A small diameter focused spot on the gain mirror is required when "as-grown" heterostructures are used. No birefringent filter was used in the resonator. In the case of our heterostructure we observed that the light was spontaneously polarized along the one of the crystallographic direction. The polarization ratio was 1000:1. The VECSEL heterostructure was of the resonant type strongly enhancing a single wavelength emission. The wavelength fine tuning was performed by heatsink temperature adjustment. The heterostructure was grown by molecular beam epitaxy. It consisted of 12 InGaAs quantum wells enclosed by GaAs barriers and a AlAs/GaAs DBR.

  4. Medical Image Segmentation Based on a Hybrid Region-Based Active Contour Model

    PubMed Central

    Liu, Tingting; Xu, Haiyong; Liu, Zhen; Zhao, Yiming; Tian, Wenzhe

    2014-01-01

    A novel hybrid region-based active contour model is presented to segment medical images with intensity inhomogeneity. The energy functional for the proposed model consists of three weighted terms: global term, local term, and regularization term. The total energy is incorporated into a level set formulation with a level set regularization term, from which a curve evolution equation is derived for energy minimization. Experiments on some synthetic and real images demonstrate that our model is more efficient compared with the localizing region-based active contours (LRBAC) method, proposed by Lankton, and more robust compared with the Chan-Vese (C-V) active contour model. PMID:25028593

  5. Special Issues Related to Hematopoietic Stem Cell Transplantation in the Eastern Mediterranean Region and the First Regional Activity Report

    PubMed Central

    Aljurf, Mahmoud; Zaidi, Syed Z; El Solh, Hassan; Hussain, Fazal; Ghavamzadeh, Ardeshir; Mahmoud, Hossam Kamel; Shamsi, Tahir; Othman, Tarek Ben; Sarhan, Mahmoud M.; Dennison, David; Ibrahim, Ahmad; Benchekroun, Said; Chaudhri, Naeem; Labar, Boris; Horowitz, Mary; Niederwieser, Dietger; Gratwohl, Alois

    2012-01-01

    Although several centers are now performing allogeneic HSCT in the Eastern Mediterranean (EM) region, the availability is still limited. Special issues including compatible donor availability and potential for alternate donor programs are discussed. In comparison to Europe & North America, differences in pattern of diseases and pre-HSCT general status particularly for patients with BM failure are described. Other differences including high seropositivity for CMV, Hepatitis B and C infection and specific observations about GVHD with its relation to genetically homogeneous community are also discussed. We report that a total of 17 HSCT programs (performing 5 or more HSCTs annually) exist in 9 countries of the EM region. Only 6 programs are currently reporting to EBMT or IBMTR. A total of 7617 HSCTs have been performed by these programs including 5701 allogeneic HSCTs. Due to low HSCT team density (1.5583 teams/10 million inhabitants vs. 14.4333 in Europe) and very low HSCT team distribution (0.2729 teams/10,000 sq km area vs. <1 to 6 teams in Europe). GNI/capita had no clear association with low HSCT activity; however improvement in infrastructure & formation of EM regional HSCT registry are needed. PMID:19043456

  6. The neck region of the myosin motor domain acts as a lever arm to generate movement.

    PubMed Central

    Uyeda, T Q; Abramson, P D; Spudich, J A

    1996-01-01

    The myosin head consists of a globular catalytic domain that binds actin and hydrolyzes ATP and a neck domain that consists of essential and regulatory light chains bound to a long alpha-helical portion of the heavy chain. The swinging neck-level model assumes that a swinging motion of the neck relative to the catalytic domain is the origin of movement. This model predicts that the step size, and consequently the sliding velocity, are linearly related to the length of the neck. We have tested this point by characterizing a series of mutant Dictyostelium myosins that have different neck lengths. The 2xELCBS mutant has an extra binding site for essential light chain. The delta RLCBS mutant myosin has an internal deletion that removes the regulatory light chain binding site. The delta BLCBS mutant lacks both light chain binding sites. Wild-type myosin and these mutant myosins were subjected to the sliding filament in vitro motility assay. As expected, mutants with shorter necks move slower than wild-type myosin in vitro. Most significantly, a mutant with a longer neck moves faster than the wild type, and the sliding velocities of these myosins are linearly related to the neck length, as predicted by the swinging neck-lever model. A simple extrapolation to zero speed predicts that the fulcrum point is in the vicinity of the SH1-SH2 region in the catalytic domain. Images Fig. 1 Fig. 2 Fig. 3 PMID:8633089

  7. Quantifying internally generated and externally forced climate signals at regional scales in CMIP5 models

    NASA Astrophysics Data System (ADS)

    Lyu, Kewei; Zhang, Xuebin; Church, John A.; Hu, Jianyu

    2015-11-01

    The Earth's climate evolves because of both internal variability and external forcings. Using Coupled Model Intercomparison Project Phase 5 (CMIP5) models, here we quantify the ratio of externally forced variance to total variance on interannual and longer time scales for regional surface air temperature (SAT) and sea level, which depends on the relative strength of externally forced signal compared to internal variability. The highest ratios are found in tropical areas for SAT but at high latitudes for sea level over the historical period when ocean dynamics and global mean thermosteric contributions are considered. Averaged globally, the ratios over a fixed time interval (e.g., 30 years) are projected to increase during the 21st century under the business-as-usual scenario (RCP8.5). In contrast, under two mitigation scenarios (RCP2.6 and RCP4.5), the ratio declines sharply by the end of the 21st century for SAT, but only declines slightly or stabilizes for sea level, indicating a slower response of sea level to climate mitigation.

  8. Activation of photodynamic therapy in vitro with Cerenkov luminescence generated from Yttrium-90 (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hartl, Brad A.; Hirschberg, Henry; Marcu, Laura; Cherry, Simon R.

    2016-03-01

    Translation of photodynamic therapy to the clinical setting has primarily been limited to easily accessible and/or superficial diseases where traditional light delivery can be performed noninvasively. Cerenkov luminescence, as generated from medically relevant radionuclides, has been suggested as a means to deliver light to deeper tissues noninvasively in order to overcome this depth limitation. We report on the use of Cerenkov luminescence generated from Yttrium-90 as a means to active the photodynamic therapy process in monolayer tumor cell cultures. The current study investigates the utility of Cerenkov luminescence for activating both the clinically relevant aminolevulinic acid at 1.0 mM and also the more efficient photosensitizer TPPS2a at 1.2 µM. Cells were incubated with aminolevulinic acid for 6 hours prior to radionuclide addition, as well as additional daily treatments for three days. TPPS2a was delivered as a single treatment with an 18 hour incubation time before radionuclide addition. Experiments were completed for both C6 glioma cells and MDA-MB-231 breast tumor cells. Although aminolevulinic acid proved ineffective for generating a therapeutic effect at any activity for either cell line, TPPS2a produced at least a 20% therapeutic effect at activities ranging from 6 to 60 µCi/well for the C6 cell line. Current results demonstrate that it may be possible to generate a therapeutic effect in vivo using Cerenkov luminescence to activate the photodynamic therapy process with clinically relevant photosensitizers.

  9. Venezuelan Equine Encephalitis Virus Activity in the Gulf Coast Region of Mexico, 2003–2010

    PubMed Central

    Adams, A. Paige; Navarro-Lopez, Roberto; Ramirez-Aguilar, Francisco J.; Lopez-Gonzalez, Irene; Leal, Grace; Flores-Mayorga, Jose M.; Travassos da Rosa, Amelia P. A.; Saxton-Shaw, Kali D.; Singh, Amber J.; Borland, Erin M.; Powers, Ann M.; Tesh, Robert B.; Weaver, Scott C.; Estrada-Franco, Jose G.

    2012-01-01

    Venezuelan equine encephalitis virus (VEEV) has been the causative agent for sporadic epidemics and equine epizootics throughout the Americas since the 1930s. In 1969, an outbreak of Venezuelan equine encephalitis (VEE) spread rapidly from Guatemala and through the Gulf Coast region of Mexico, reaching Texas in 1971. Since this outbreak, there have been very few studies to determine the northward extent of endemic VEEV in this region. This study reports the findings of serologic surveillance in the Gulf Coast region of Mexico from 2003–2010. Phylogenetic analysis was also performed on viral isolates from this region to determine whether there have been substantial genetic changes in VEEV since the 1960s. Based on the findings of this study, the Gulf Coast lineage of subtype IE VEEV continues to actively circulate in this region of Mexico and appears to be responsible for infection of humans and animals throughout this region, including the northern State of Tamaulipas, which borders Texas. PMID:23133685

  10. MAG4 versus Alternative Techniques for Forecasting Active-Region Flare Productivity

    NASA Astrophysics Data System (ADS)

    Falconer, David; Moore, Ronald L.; Barghouty, Abdulnasser F; Khazanov, Igor

    2014-06-01

    MAG4 is a technique of forecasting an active region's rate of production of major flares in the coming few days from a free-magnetic-energy proxy. We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region’s major-flare productivity from alternative observed aspects of the active region. We demonstrate the method by measuring the difference in performance between the “Present MAG4” technique and each of three alternative techniques, called “McIntosh Active-Region Class,” “Total Magnetic Flux,” and “Next MAG4.” We do this by using (1) the MAG4 database of magnetograms and major-flare histories of sunspot active regions, (2) the NOAA table of the major-flare productivity of each of 60 McIntosh active-region classes of sunspot active regions, and (3) five technique-performance metrics (Heidke Skill Score, True Skill Score, Percent Correct, Probability of Detection, and False Alarm Rate) evaluated from 2000 random two-by-two contingency tables obtained from the databases. We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4). Funding for this research came from NASA’s Game Changing Development Program, Johnson Space Center’s Space Radiation Analysis Group (SRAG), and AFOSR’s Multi-University Research Initiative. In particular, funding was facilitated by Dr. Dan Fry (NASA-JSC) and David Moore (NASA-LaRC).

  11. Spouse-to-Spouse Transmission and Evolution of Hypervariable Region 1 and 5’ Untranslated Region of Hepatitis C Virus Analyzed by Next-Generation Sequencing

    PubMed Central

    Caraballo Cortes, Kamila; Zagordi, Osvaldo; Jabłońska, Joanna; Pawełczyk, Agnieszka; Kubisa, Natalia; Perlejewski, Karol; Bukowska-Ośko, Iwona; Płoski, Rafał; Radkowski, Marek; Laskus, Tomasz

    2016-01-01

    Hepatitis C virus (HCV) transmission between spouses remains poorly characterized, largely due to the limited availability of samples from the early stage of infection, as well as methodological constraints. A fifty-eight year-old male developed acute hepatitis C infection and his 53-year old spouse has been HCV-positive for over 10 years. Serum samples were collected from both at the time of acute hepatitis C diagnosis in male (baseline) and then at 9 and 13 months. Hypervariable region 1 (HVR1) and 5’ untranslated region (5’UTR) sequences were amplified and subjected to next generation sequencing (NGS) using a pyrosequencing platform. Genetic variants were inferred by Shorah reconstruction method and compared by phylogenetic and sequence diversity analysis. As the sequencing error of the procedure was previously determined to be ≤ 1.5%, the analysis was conducted with and without the 1.5% cut-off with regard to the frequency of variants. No identical HVR1 variants were identified in spouses at baseline and follow-up samples regardless whether the cut-off was applied or not. However, there was high similarity (98.3%) between a minor baseline donor variant (1.7% frequency) and the most abundant baseline recipient variant (62.5% frequency). Furthermore, donor and recipient strains clustered together when compared to 10 control subjects from the same area and infected with the same HCV subtype. There was an increase in HVR1 complexity (number of genetic variants) over time in both spouses. In contrast, the 5'UTR region was stable and of low complexity throughout the study. In conclusion, intrafamilial HCV transmission may be established by a very minor variant and investigation of this phenomenon requires high-sensitivity assays, such as NGS. PMID:26918636

  12. Campi Flegrei Deep Drilling Project and geothermal activities in Campania Region (Southern Italy)

    NASA Astrophysics Data System (ADS)

    De Natale, Giuseppe; Troise, Claudia; Troiano, Antonio; Giulia Di Giuseppe, Maria; Mormone, Angela; Carlino, Stefano; Somma, Renato; Tramelli, Anna; Vertechi, Enrico; Sangianantoni, Agata; Piochi, Monica

    2013-04-01

    The Campanian volcanic area has a huge geothermal potential (Carlino et al., 2012), similar to the Larderello-Radicondoli-Amiata region, in Tuscany (Italy), which has been the first site in the World exploited for electric production. Recently, the Campi Flegrei Deep Drilling Project (CFDDP), sponsored by ICDP and devoted to understand and mitigate the extreme volcanic risk in the area, has also risen new interest for geothermal exploration in several areas of Italy. Following the new Italian regulations which favour and incentivise innovative pilot power plants with zero emission, several geothermal projects have started in the Campania Region, characterized by strict cooperation among large to small industries, Universities and public Research Centers. INGV department of Naples (Osservatorio Vesuviano) has the technical/scientific leadership of such initiatives. Most of such projects are coordinated in the framework of the Regional District for Energy, in which a large part is represented by geothermal resource. Leading geothermal projects in the area include 'FORIO' pilot plant project, aimed to build two small (5 MWe each one) power plants in the Ischia island and two projects aimed to build pilot power plants in the Agnano-Fuorigrotta area in the city of Naples, at the easternmost part of Campi Flegrei caldera. One of the Campi Flegrei projects, 'SCARFOGLIO', is aimed to build a 5 MWe geothermal power plant in the Agnano area, whereas the 'START' project has the goal to build a tri-generation power plant in the Fuorigrotta area, fed mainly by geothermal source improved by solar termodynamic and bio-mass. Meanwhile such projects enter the field work operational phase, the pilot hole drilling of the CFDDP project, recently completed, represents an important experience for several operational aspects, which should contitute an example to be followed by the next geothermal activities in the area. It has been furthermore a source of valuable data for geothermal

  13. Ocean Pollution as a Result of Onshore Offshore Petroleum Activities in the African Gulf of Guinea Region

    NASA Astrophysics Data System (ADS)

    Abubakar, B.

    2007-05-01

    increasing cases of pollution of farmlands, rivers, wells and the environment in general. Apart from all these, what is even becoming more worrisome is that none of all these oil firms operating in the region is able to account on how it disposes its industrial toxic waste generated as a result of its industrial activities within the region. Finally Geological strata are adversely destroyed by seismographic activities, Sea creatures are destroyed by oil pollution and Means of livelihood of revering dwellers are often threatened by pollution. RECOMMENDATIONS After identifying how the pollution in the Gulf of Guinea region is increasing in relation to the increasing petroleum activities, I have come up with the following suggestions/recommendations. 1. AFRICAN UNION RESOLUTION The Organization of the Petroleum Exporting Countries (OPEC) in conjunction with the International Atomic Energy Agency (IAEA) should use their capacity to be able to influence the African Union (AU) to pass a resolution banning the illegal dumping of radioactive waste, Gas flaring and Costal bunkering in this part of the world. 2. RESEARCH AND INVESTIGATION The Organization of the Petroleum Exporting Countries, in conjunction with the United Nations Environmental Agency, the International Atomic Energy Agency and with the corporation of the African Union should send team of researchers to come and investigate this trend on petroleum pollution in the Gulf of Guinea region and proffer possible solutions in checking the menace.

  14. Regional brain effects of sodium azide treatment on cytochrome oxidase activity: a quantitative histochemical study.

    PubMed

    Cada, A; Gonzalez-Lima, F; Rose, G M; Bennett, M C

    1995-12-01

    The objective of the present study was to determine if regional variation in brain cytochrome oxidase activity was observed following systemic administration of sodium azide. An image analysis system calibrated with internal standards of known cytochrome oxidase activity was used to quantify cytochrome oxidase in histochemically stained brain sections. Rats receiving chronic infusion of sodium azide (400 micrograms/hr), which were sacrificed after two weeks, showed a substantial decrease in brain cytochrome oxidase activity over those infused with saline. All of the 22 regions sampled from telencephalic, diencephalic, and mesencephalic levels, showed a significant activity reduction which ranged between 26% and 37%. The regions that appeared significantly more vulnerable to the sodium azide effects were the mesencephalic reticular formation and the central amygdala, which displayed the largest decrease in activity. In addition, interregional correlations of activity showed a deeply modified pattern of correlative metabolic activity between hippocampal, amygdaloid and cortical areas after azide treatment. The regional effects found were consistent with azide-induced learning and memory dysfunctions. PMID:8847994

  15. Determining heating timescales in solar active region cores from AIA/SDO Fe XVIII images

    SciTech Connect

    Ugarte-Urra, Ignacio; Warren, Harry P.

    2014-03-01

    We present a study of the frequency of transient brightenings in the core of solar active regions as observed in the Fe XVIII line component of AIA/SDO 94 Å filter images. The Fe XVIII emission is isolated using an empirical correction to remove the contribution of 'warm' emission to this channel. Comparing with simultaneous observations from EIS/Hinode, we find that the variability observed in Fe XVIII is strongly correlated with the emission from lines formed at similar temperatures. We examine the evolution of loops in the cores of active regions at various stages of evolution. Using a newly developed event detection algorithm, we characterize the distribution of event frequency, duration, and magnitude in these active regions. These distributions are similar for regions of similar age and show a consistent pattern as the regions age. This suggests that these characteristics are important constraints for models of solar active regions. We find that the typical frequency of the intensity fluctuations is about 1400 s for any given line of sight, i.e., about two to three events per hour. Using the EBTEL 0D hydrodynamic model, however, we show that this only sets a lower limit on the heating frequency along that line of sight.

  16. New role for Kruppel-like factor 14 as a transcriptional activator involved in the generation of signaling lipids.

    PubMed

    de Assuncao, Thiago M; Lomberk, Gwen; Cao, Sheng; Yaqoob, Usman; Mathison, Angela; Simonetto, Douglas A; Huebert, Robert C; Urrutia, Raul A; Shah, Vijay H

    2014-05-30

    Sphingosine kinase 1 (SK1) is an FGF-inducible gene responsible for generation of sphingosine-1-phosphate, a critical lipid signaling molecule implicated in diverse endothelial cell functions. In this study, we identified SK1 as a target of the canonical FGF2/FGF receptor 1 activation pathway in endothelial cells and sought to identify novel transcriptional pathways that mediate lipid signaling. Studies using the 1.9-kb SK1 promoter and deletion mutants revealed that basal and FGF2-stimulated promoter activity occurred through two GC-rich regions located within 633 bp of the transcription start site. Screening for GC-rich binding transcription factors that could activate this site demonstrated that KLF14, a gene implicated in obesity and the metabolic syndrome, binds to this region. Congruently, overexpression of KLF14 increased basal and FGF2-stimulated SK1 promoter activity by 3-fold, and this effect was abrogated after mutation of the GC-rich sites. In addition, KLF14 siRNA transfection decreased SK1 mRNA and protein levels by 3-fold. Congruently, SK1 mRNA and protein levels were decreased in livers from KLF14 knock-out mice. Combined, luciferase, gel shift, and chromatin immunoprecipitation assays showed that KLF14 couples to p300 to increase the levels of histone marks associated with transcriptional activation (H4K8ac and H3K14ac), while decreasing repressive marks (H3K9me3 and H3K27me3). Collectively, the results demonstrate a novel mechanism whereby SK1 lipid signaling is regulated by epigenetic modifications conferred by KLF14 and p300. Thus, this is the first description of the activity and mechanisms underlying the function of KLF14 as an activator protein and novel regulator of lipid signaling. PMID:24759103

  17. New Role for Kruppel-like Factor 14 as a Transcriptional Activator Involved in the Generation of Signaling Lipids*

    PubMed Central

    de Assuncao, Thiago M.; Lomberk, Gwen; Cao, Sheng; Yaqoob, Usman; Mathison, Angela; Simonetto, Douglas A.; Huebert, Robert C.; Urrutia, Raul A.; Shah, Vijay H.

    2014-01-01

    Sphingosine kinase 1 (SK1) is an FGF-inducible gene responsible for generation of sphingosine