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Sample records for multiple flaring activity

  1. CALCULATING SEPARATE MAGNETIC FREE ENERGY ESTIMATES FOR ACTIVE REGIONS PRODUCING MULTIPLE FLARES: NOAA AR11158

    Tarr, Lucas; Longcope, Dana; Millhouse, Margaret [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2013-06-10

    It is well known that photospheric flux emergence is an important process for stressing coronal fields and storing magnetic free energy, which may then be released during a flare. The Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) captured the entire emergence of NOAA AR 11158. This region emerged as two distinct bipoles, possibly connected underneath the photosphere, yet characterized by different photospheric field evolutions and fluxes. The combined active region complex produced 15 GOES C-class, two M-class, and the X2.2 Valentine's Day Flare during the four days after initial emergence on 2011 February 12. The M and X class flares are of particular interest because they are nonhomologous, involving different subregions of the active region. We use a Magnetic Charge Topology together with the Minimum Current Corona model of the coronal field to model field evolution of the complex. Combining this with observations of flare ribbons in the 1600 A channel of the Atmospheric Imaging Assembly on board SDO, we propose a minimization algorithm for estimating the amount of reconnected flux and resulting drop in magnetic free energy during a flare. For the M6.6, M2.2, and X2.2 flares, we find a flux exchange of 4.2 Multiplication-Sign 10{sup 20} Mx, 2.0 Multiplication-Sign 10{sup 20} Mx, and 21.0 Multiplication-Sign 10{sup 20} Mx, respectively, resulting in free energy drops of 3.89 Multiplication-Sign 10{sup 30} erg, 2.62 Multiplication-Sign 10{sup 30} erg, and 1.68 Multiplication-Sign 10{sup 32} erg.

  2. Study of magnetic helicity injection in the active region NOAA 9236 producing multiple flare-associated coronal mass ejection events

    Park, Sung-Hong; Cho, Kyung-Suk; Bong, Su-Chan; Kumar, Pankaj; Kim, Yeon-Han; Park, Young-Deuk; Kusano, Kanya; Chae, Jongchul; Park, So-Young

    2013-01-01

    To better understand a preferred magnetic field configuration and its evolution during coronal mass ejection (CME) events, we investigated the spatial and temporal evolution of photospheric magnetic fields in the active region NOAA 9236 that produced eight flare-associated CMEs during the time period of 2000 November 23-26. The time variations of the total magnetic helicity injection rate and the total unsigned magnetic flux are determined and examined not only in the entire active region but also in some local regions such as the main sunspots and the CME-associated flaring regions using SOHO/MDI magnetogram data. As a result, we found that (1) in the sunspots, a large amount of positive (right-handed) magnetic helicity was injected during most of the examined time period, (2) in the flare region, there was a continuous injection of negative (left-handed) magnetic helicity during the entire period, accompanied by a large increase of the unsigned magnetic flux, and (3) the flaring regions were mainly composed of emerging bipoles of magnetic fragments in which magnetic field lines have substantially favorable conditions for making reconnection with large-scale, overlying, and oppositely directed magnetic field lines connecting the main sunspots. These observational findings can also be well explained by some MHD numerical simulations for CME initiation (e.g., reconnection-favored emerging flux models). We therefore conclude that reconnection-favored magnetic fields in the flaring emerging flux regions play a crucial role in producing the multiple flare-associated CMEs in NOAA 9236.

  3. KEPLER FLARES. I. ACTIVE AND INACTIVE M DWARFS

    Hawley, Suzanne L.; Davenport, James R. A.; Kowalski, Adam F.; Wisniewski, John P.; Deitrick, Russell; Hilton, Eric J. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Hebb, Leslie, E-mail: slhawley@uw.edu [Department of Physics, Hobart and William Smith Colleges, 300 Pulteney Street, Geneva, NY 14456 (United States)

    2014-12-20

    We analyzed Kepler short-cadence M dwarf observations. Spectra from the Astrophysical Research Consortium 3.5 m telescope identify magnetically active (Hα in emission) stars. The active stars are of mid-M spectral type, have numerous flares, and have well-defined rotational modulation due to starspots. The inactive stars are of early M type, exhibit less starspot signature, and have fewer flares. A Kepler to U-band energy scaling allows comparison of the Kepler flare frequency distributions with previous ground-based data. M dwarfs span a large range of flare frequency and energy, blurring the distinction between active and inactive stars designated solely by the presence of Hα. We analyzed classical and complex (multiple peak) flares on GJ 1243, finding strong correlations between flare energy, amplitude, duration, and decay time, with only a weak dependence on rise time. Complex flares last longer and have higher energy at the same amplitude, and higher energy flares are more likely to be complex. A power law fits the energy distribution for flares with log E{sub K{sub p}}> 31 erg, but the predicted number of low-energy flares far exceeds the number observed, at energies where flares are still easily detectable, indicating that the power-law distribution may flatten at low energy. There is no correlation of flare occurrence or energy with starspot phase, the flare waiting time distribution is consistent with flares occurring randomly in time, and the energies of consecutive flares are uncorrelated. These observations support a scenario where many independent active regions on the stellar surface are contributing to the observed flare rate.

  4. KEPLER FLARES. I. ACTIVE AND INACTIVE M DWARFS

    Hawley, Suzanne L.; Davenport, James R. A.; Kowalski, Adam F.; Wisniewski, John P.; Deitrick, Russell; Hilton, Eric J.; Hebb, Leslie

    2014-01-01

    We analyzed Kepler short-cadence M dwarf observations. Spectra from the Astrophysical Research Consortium 3.5 m telescope identify magnetically active (Hα in emission) stars. The active stars are of mid-M spectral type, have numerous flares, and have well-defined rotational modulation due to starspots. The inactive stars are of early M type, exhibit less starspot signature, and have fewer flares. A Kepler to U-band energy scaling allows comparison of the Kepler flare frequency distributions with previous ground-based data. M dwarfs span a large range of flare frequency and energy, blurring the distinction between active and inactive stars designated solely by the presence of Hα. We analyzed classical and complex (multiple peak) flares on GJ 1243, finding strong correlations between flare energy, amplitude, duration, and decay time, with only a weak dependence on rise time. Complex flares last longer and have higher energy at the same amplitude, and higher energy flares are more likely to be complex. A power law fits the energy distribution for flares with log E K p > 31 erg, but the predicted number of low-energy flares far exceeds the number observed, at energies where flares are still easily detectable, indicating that the power-law distribution may flatten at low energy. There is no correlation of flare occurrence or energy with starspot phase, the flare waiting time distribution is consistent with flares occurring randomly in time, and the energies of consecutive flares are uncorrelated. These observations support a scenario where many independent active regions on the stellar surface are contributing to the observed flare rate

  5. The evolution of flaring and non-flaring active regions

    Kilcik, A.; Yurchyshyn, V.; Sahin, S.; Sarp, V.; Obridko, V.; Ozguc, A.; Rozelot, J. P.

    2018-06-01

    According to the modified Zurich classification, sunspot groups are classified into seven different classes (A, B, C, D, E, F and H) based on their morphology and evolution. In this classification, classes A and B, which are small groups, describe the beginning of sunspot evolution, while classes D, E and F describe the large and evolved groups. Class C describes the middle phase of sunspot evolution and the class H describes the end of sunspot evolution. Here, we compare the lifetime and temporal evolution of flaring and non-flaring active regions (ARs), and the flaring effect on ARs in these groups in detail for the last two solar cycles (1996 through 2016). Our main findings are as follows: (i) Flaring sunspot groups have longer lifetimes than non-flaring ones. (ii) Most of the class A, B and C flaring ARs rapidly evolve to higher classes, while this is not applicable for non-flaring ARs. More than 50 per cent of the flaring A, B and C groups changed morphologically, while the remaining D, E, F and H groups did not change remarkably after the flare activity. (iii) 75 per cent of all flaring sunspot groups are large and complex. (iv) There is a significant increase in the sunspot group area in classes A, B, C, D and H after flaring activity. In contrast, the sunspot group area of classes E and F decreased. The sunspot counts of classes D, E and F decreased as well, while classes A, B, C and H showed an increase.

  6. The Crab Nebula flaring activity

    Montani, G., E-mail: giovanni.montani@frascati.enea.it [ENEA – C.R, UTFUS-MAG, via Enrico Fermi 45, I-00044 Frascati (RM) (Italy); Dipartimento di Fisica, Università di Roma “Sapienza”, p.le Aldo Moro 5, I-00185 Roma (Italy); Bernardini, M.G. [INAF – Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy)

    2014-12-12

    The discovery made by AGILE and Fermi of a short time scale flaring activity in the gamma-ray energy emission of the Crab Nebula is a puzzling and unexpected feature, challenging particle acceleration theory. In the present work we propose the shock-induced magnetic reconnection as a viable mechanism to explain the Crab flares. We postulate that the emitting region is located at ∼10{sup 15} cm from the central pulsar, well inside the termination shock, which is exactly the emitting region size as estimated by the overall duration of the phenomenon ∼1 day. We find that this location corresponds to the radial distance at which the shock-induced magnetic reconnection process is able to accelerate the electrons up to a Lorentz factor ∼10{sup 9}, as required by the spectral fit of the observed Crab flare spectrum. The main merit of the present analysis is to highlight the relation between the observational constraints to the flare emission and the radius at which the reconnection can trigger the required Lorentz factor. We also discuss different scenarios that can induce the reconnection. We conclude that the existence of a plasma instability affecting the wind itself as the Weibel instability is the privileged scenario in our framework.

  7. On the possible cyclic recurrence of flare activity of flare stars in the pleiades

    Mirzoyan, L.V.; Oganyan, G.V.

    1977-01-01

    The flare activity of flare stars in Pleiades is investigated. It is shown that according to flare statistics only one half of the probable Pleiades members with low luminosities have flare activity throughout the observation period. Two assumptions are suggested to explain this contradiction with the concept on the evolutionary importance of the flare star phase which all the dwarf stars go through: cyclic nature of the flare activity and large dispersion in flare activity phase durations for equally luminous stars. Certain evidences to support cyclic flare activity assumption are adduced

  8. Active Longitude and Solar Flare Occurrences

    Gyenge, N.; Ludmány, A.; Baranyi, T.

    2016-02-01

    The aim of the present work is to specify the spatio-temporal characteristics of flare activity observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Geostationary Operational Environmental Satellite (GOES) in connection with the behavior of the longitudinal domain of enhanced sunspot activity known as active longitude (AL). By using our method developed for this purpose, we identified the AL in every Carrington Rotation provided by the Debrecen Photoheliographic Data. The spatial probability of flare occurrence has been estimated depending on the longitudinal distance from AL in the northern and southern hemispheres separately. We have found that more than 60% of the RHESSI and GOES flares is located within +/- 36^\\circ from the AL. Hence, the most flare-productive active regions tend to be located in or close to the active longitudinal belt. This observed feature may allow for the prediction of the geo-effective position of the domain of enhanced flaring probability. Furthermore, we studied the temporal properties of flare occurrence near the AL and several significant fluctuations were found. More precisely, the results of the method are the following fluctuations: 0.8, 1.3, and 1.8 years. These temporal and spatial properties of the solar flare occurrence within the active longitudinal belts could provide us with an enhanced solar flare forecasting opportunity.

  9. Observations of vector magnetic fields in flaring active regions

    Chen, Jimin; Wang, Haimin; Zirin, Harold; Ai, Guoxiang

    1994-01-01

    We present vector magnetograph data of 6 active regions, all of which produced major flares. Of the 20 M-class (or above) flares, 7 satisfy the flare conditions prescribed by Hagyard (high shear and strong transverse fields). Strong photospheric shear, however, is not necessarily a condition for a flare. We find an increase in the shear for two flares, a 6-deg shear increase along the neutral line after a X-2 flare and a 13-deg increase after a M-1.9 flare. For other flares, we did not detect substantial shear changes.

  10. SLIPPING MAGNETIC RECONNECTIONS WITH MULTIPLE FLARE RIBBONS DURING AN X-CLASS SOLAR FLARE

    Zheng, Ruisheng; Chen, Yao; Wang, Bing

    2016-01-01

    With the observations of the Solar Dynamics Observatory , we present the slipping magnetic reconnections with multiple flare ribbons (FRs) during an X1.2 eruptive flare on 2014 January 7. A center negative polarity was surrounded by several positive ones, and three FRs appeared. The three FRs showed apparent slipping motions, and hook structures formed at their ends. Due to the moving footpoints of the erupting structures, one tight semi-circular hook disappeared after the slippage along its inner and outer edges, and coronal dimmings formed within the hook. The east hook also faded as a result of the magnetic reconnection between the arcades of a remote filament and a hot loop that was impulsively heated by the under flare loops. Our results are accordant with the slipping magnetic reconnection regime in three-dimensional standard model for eruptive flares. We suggest that the complex structures of the flare are likely a consequence of the more complex flux distribution in the photosphere, and the eruption involves at least two magnetic reconnections.

  11. Recurrent flares in active region NOAA 11283

    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

  12. Temporal and Periodic Variations of Sunspot Counts in Flaring and Non-Flaring Active Regions

    Kilcik, A.; Yurchyshyn, V.; Donmez, B.; Obridko, V. N.; Ozguc, A.; Rozelot, J. P.

    2018-04-01

    We analyzed temporal and periodic variations of sunspot counts (SSCs) in flaring (C-, M-, or X-class flares), and non-flaring active regions (ARs) for nearly three solar cycles (1986 through 2016). Our main findings are as follows: i) temporal variations of monthly means of the daily total SSCs in flaring and non-flaring ARs behave differently during a solar cycle and the behavior varies from one cycle to another; during Solar Cycle 23 temporal SSC profiles of non-flaring ARs are wider than those of flaring ARs, while they are almost the same during Solar Cycle 22 and the current Cycle 24. The SSC profiles show a multi-peak structure and the second peak of flaring ARs dominates the current Cycle 24, while the difference between peaks is less pronounced during Solar Cycles 22 and 23. The first and second SSC peaks of non-flaring ARs have comparable magnitude in the current solar cycle, while the first peak is nearly absent in the case of the flaring ARs of the same cycle. ii) Periodic variations observed in the SSCs profiles of flaring and non-flaring ARs derived from the multi-taper method (MTM) spectrum and wavelet scalograms are quite different as well, and they vary from one solar cycle to another. The largest detected period in flaring ARs is 113± 1.6 days while we detected much longer periodicities (327± 13, 312 ± 11, and 256± 8 days) in the non-flaring AR profiles. No meaningful periodicities were detected in the MTM spectrum of flaring ARs exceeding 55± 0.7 days during Solar Cycles 22 and 24, while a 113± 1.3 days period was detected in flaring ARs of Solar Cycle 23. For the non-flaring ARs the largest detected period was only 31± 0.2 days for Cycle 22 and 72± 1.3 days for the current Cycle 24, while the largest measured period was 327± 13 days during Solar Cycle 23.

  13. Photospheric Magnetic Field Properties of Flaring versus Flare-quiet Active Regions. II. Discriminant Analysis

    Leka, K. D.; Barnes, G.

    2003-10-01

    We apply statistical tests based on discriminant analysis to the wide range of photospheric magnetic parameters described in a companion paper by Leka & Barnes, with the goal of identifying those properties that are important for the production of energetic events such as solar flares. The photospheric vector magnetic field data from the University of Hawai'i Imaging Vector Magnetograph are well sampled both temporally and spatially, and we include here data covering 24 flare-event and flare-quiet epochs taken from seven active regions. The mean value and rate of change of each magnetic parameter are treated as separate variables, thus evaluating both the parameter's state and its evolution, to determine which properties are associated with flaring. Considering single variables first, Hotelling's T2-tests show small statistical differences between flare-producing and flare-quiet epochs. Even pairs of variables considered simultaneously, which do show a statistical difference for a number of properties, have high error rates, implying a large degree of overlap of the samples. To better distinguish between flare-producing and flare-quiet populations, larger numbers of variables are simultaneously considered; lower error rates result, but no unique combination of variables is clearly the best discriminator. The sample size is too small to directly compare the predictive power of large numbers of variables simultaneously. Instead, we rank all possible four-variable permutations based on Hotelling's T2-test and look for the most frequently appearing variables in the best permutations, with the interpretation that they are most likely to be associated with flaring. These variables include an increasing kurtosis of the twist parameter and a larger standard deviation of the twist parameter, but a smaller standard deviation of the distribution of the horizontal shear angle and a horizontal field that has a smaller standard deviation but a larger kurtosis. To support the

  14. ABRUPT LONGITUDINAL MAGNETIC FIELD CHANGES IN FLARING ACTIVE REGIONS

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

    2010-01-01

    We characterize the changes in the longitudinal photospheric magnetic field during 38 X-class and 39 M-class flares within 65 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 ∼10 G to as high as ∼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 0 of disk center, as in our observations, if photospheric field tilts increase during flares as predicted by Hudson et al.

  15. Forecasting Flare Activity Using Deep Convolutional Neural Networks

    Hernandez, T.

    2017-12-01

    Current operational flare forecasting relies on human morphological analysis of active regions and the persistence of solar flare activity through time (i.e. that the Sun will continue to do what it is doing right now: flaring or remaining calm). In this talk we present the results of applying deep Convolutional Neural Networks (CNNs) to the problem of solar flare forecasting. CNNs operate by training a set of tunable spatial filters that, in combination with neural layer interconnectivity, allow CNNs to automatically identify significant spatial structures predictive for classification and regression problems. We will start by discussing the applicability and success rate of the approach, the advantages it has over non-automated forecasts, and how mining our trained neural network provides a fresh look into the mechanisms behind magnetic energy storage and release.

  16. Proton Flares in Solar Activity Complexes: Possible Origins and Consequences

    Isaeva, E. S.; Tomozov, V. M.; Yazev, S. A.

    2018-03-01

    Solar flares observed during the 24th solar-activity cycle and accompanied by fluxes of particles detected at the Earth's orbit with intensities exceeding 10 particles cm-2 s-1 and energies of more than 10 MeV per particle mainly occurred in activity complexes (82% of cases), with 80% of these occurring no more than 20 heliographic degrees from the nearest coronal holes. The correlation between the X-ray classes of flares and the proton fluxes detected at the Earth's orbit is weak. The work presented here supports the hypothesis that the leakage of particles into the heliosphere is due to the existence of long-lived magnetic channels, which facilitate the transport of flare-accelerated particles into the boundary regions of open magnetic structures of coronal holes. The possible contribution of exchange reconnection in the formation of such channels and the role of exchange reconnection in the generation of flares are discussed.

  17. Multifractality as a Measure of Complexity in Solar Flare Activity

    Sen, Asok K.

    2007-03-01

    In this paper we use the notion of multifractality to describe the complexity in H α flare activity during the solar cycles 21, 22, and 23. Both northern and southern hemisphere flare indices are analyzed. Multifractal behavior of the flare activity is characterized by calculating the singularity spectrum of the daily flare index time series in terms of the Hölder exponent. The broadness of the singularity spectrum gives a measure of the degree of multifractality or complexity in the flare index data. The broader the spectrum, the richer and more complex is the structure with a higher degree of multifractality. Using this broadness measure, complexity in the flare index data is compared between the northern and southern hemispheres in each of the three cycles, and among the three cycles in each of the two hemispheres. Other parameters of the singularity spectrum can also provide information about the fractal properties of the flare index data. For instance, an asymmetry to the left or right in the singularity spectrum indicates a dominance of high or low fractal exponents, respectively, reflecting a relative abundance of large or small fluctuations in the total energy emitted by the flares. Our results reveal that in the even (22nd) cycle the singularity spectra are very similar for the northern and southern hemispheres, whereas in the odd cycles (21st and 23rd) they differ significantly. In particular, we find that in cycle 21, the northern hemisphere flare index data have higher complexity than its southern counterpart, with an opposite pattern prevailing in cycle 23. Furthermore, small-scale fluctuations in the flare index time series are predominant in the northern hemisphere in the 21st cycle and are predominant in the southern hemisphere in the 23rd cycle. Based on these findings one might suggest that, from cycle to cycle, there exists a smooth switching between the northern and southern hemispheres in the multifractality of the flaring process. This new

  18. The Photospheric Flow near the Flare Locations of Active Regions

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    in the active regions along with few locations of upflows. The localised upflows are observed in the light bridges and emerging flux regions with different speeds (Beckers & Schroter 1969). The flow patterns of flare locations in the active regions are observed by using the tower vector magnetograph (TVM) of Marshall.

  19. SIGN SINGULARITY AND FLARES IN SOLAR ACTIVE REGION NOAA 11158

    Sorriso-Valvo, L.; De Vita, G. [IMIP-CNR, U.O.S. LICRYL di Cosenza, Ponte P. Bucci, Cubo 31C, I-87036 Rende (Italy); Kazachenko, M. D.; Krucker, S.; Welsch, B. T.; Fisher, G. H. [Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley 94720, California (United States); Primavera, L.; Servidio, S.; Lepreti, F.; Carbone, V. [Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, Cubo 31C, I-87036 Rende (Italy); Vecchio, A., E-mail: sorriso@fis.unical.it [INGV, Sede di Cosenza, Ponte P. Bucci, Cubo 30C, I-87036 Rende (Italy)

    2015-03-01

    Solar Active Region NOAA 11158 has hosted a number of strong flares, including one X2.2 event. The complexity of current density and current helicity are studied through cancellation analysis of their sign-singular measure, which features power-law scaling. Spectral analysis is also performed, revealing the presence of two separate scaling ranges with different spectral index. The time evolution of parameters is discussed. Sudden changes of the cancellation exponents at the time of large flares and the presence of correlation with Extreme-Ultra-Violet and X-ray flux suggest that eruption of large flares can be linked to the small-scale properties of the current structures.

  20. Interacting CMEs and their associated flare and SEP activities

    Shanmugaraju, A.; Prasanna Subramanian, S.

    2014-08-01

    We have analyzed a set of 25 interacting events which are associated with the DH type II bursts. These events are selected from the Coronal Mass Ejections (CMEs) observed during the period 1997-2010 in SOHO/LASCO and DH type IIs observed in Wind/WAVES. Their pre and primary CMEs from nearby active regions are identified using SOHO/LASCO and EIT images and their height-time diagrams. Their interacting time and height are obtained, and their associated activities, such as, flares and Solar Energetic Particles (>10 pfu) are also investigated. Results from the analysis are: primary CMEs are much faster than the pre-CMEs, their X-ray flares are also stronger (X- and M-class) compared to the flares (C- and M-class) of pre-CMEs. Most of the events (22/25) occurred during the period 2000-2006. From the observed width and speed of pre and primary CMEs, it is found that the pre-CMEs are found to be less energetic than the primary CMEs. While the primary CMEs are tracked up to the end of LASCO field of view (30 Rs), most of the pre-CMEs can be tracked up to <26 Rs. The SEP intensity is found to be related with the integrated flux of X-ray flares associated with the primary CMEs for nine events originating from the western region.

  1. Prediction of flare activity of stellar aggregates. I. Theoretical part

    Mnatsakanyan, M.A.; Mirzoyan, A.L.

    1989-01-01

    The problem is posed of predicting the number n k (t) of flare stars that have exhibited precisely k flares by the time t on the basis of data on these quantities known during the total time T of observations of the aggregate. The problem posed by Ambartsumyan of determining the distribution function f(ν) of the true frequency of stellar flares from known chronology of these data is equivalent to the limiting form of their formulation - prediction in the future over an infinitely long time. An exact analytic solution of the problem obtained without any assumption about the function f(ν) is given. It permits prediction of the steady flare activity of the aggregate into both the future and the (known) past. It follows from this solution that prediction into the future is in principle impossible to times that exceed the doubled time 2T of the available observations (this means that the problem of determining of the function f(ν) cannot be solved). Moreover, because of the unavoidable fluctuations in the observational data n k (T), such prediction is limited to even shorter times, and these are shorter the larger the value of k. Prediction into the past and into the future on the basis of the data n k (T) at the present time and its possible errors due to small fluctuations in these data are illustrated for the examples of the Pleiades and the Orion aggregate

  2. KIC 9451096: Magnetic Activity, Flares and Differential Rotation

    Özdarcan, O.; Yoldaş, E.; Dal, H. A.

    2018-04-01

    We present a spectroscopic and photometric analysis of KIC 9451096. The combined spectroscopic and photometric modelling shows that the system is a detached eclipsing binary in a circular orbit and composed of F5V + K2V components. Subtracting the best-fitting light curve model from the whole long cadence data reveals additional low (mmag) amplitude light variations in time and occasional flares, suggesting a low, but still remarkable level of magnetic spot activity on the K2V component. Analyzing the rotational modulation of the light curve residuals enables us to estimate the differential rotation coefficient of the K2V component as k = 0.069 ± 0.008, which is 3 times weaker compared with the solar value of k = 0.19, assuming a solar type differential rotation. We find the stellar flare activity frequency for the K2V component as 0.000368411 h-1 indicating a low magnetic activity level.

  3. A magnetic bald-patch flare in solar active region 11117

    Jiang, Chao-Wei; Feng, Xue-Shang; Wu, Shi-Tsan; Hu, Qiang

    2017-09-01

    With SDO observations and a data-constrained magnetohydrodynamics (MHD) model, we identify a confined multi-ribbon flare that occurred on 2010 October 25 in solar active region 11117 as a magnetic bald patch (BP) flare with strong evidence. From the photospheric magnetic field observed by SDO/HMI, we find there are indeed magnetic BPs on the polarity inversion lines (PILs) which match parts of the flare ribbons. From the 3D coronal magnetic field derived from an MHD relaxation model constrained by the vector magnetograms, we find strikingly good agreement of the BP separatrix surface (BPSS) footpoints with the flare ribbons, and the BPSS itself with the hot flaring loop system. Moreover, the triggering of the BP flare can be attributed to a small flux emergence under the lobe of the BPSS, and the relevant change of coronal magnetic field through the flare is reproduced well by the pre-flare and post-flare MHD solutions, which match the corresponding pre- and post-flare AIA observations, respectively. Our work contributes to the study of non-typical flares that constitute the majority of solar flares but which cannot be explained by the standard flare model.

  4. Dynamic Precursors of Flares in Active Region NOAA 10486

    Korsós, M. B.; Gyenge, N.; Baranyi, T.; Ludmány, A.

    2015-03-01

    Four different methods are applied here to study the precursors of flare activity in the Active Region NOAA 10486. Two approaches track the temporal behaviour of suitably chosen features (one, the weighted hori- zontal gradient W G M , is the generalized form of the horizontal gradient of the magnetic field, G M ; the other is the sum of the horizontal gradient of the magnetic field, G S , for all sunspot pairs). W G M is a photospheric indicator, that is a proxy measure of magnetic non-potentiality of a specific area of the active region, i.e., it captures the temporal variation of the weighted horizontal gradient of magnetic flux summed up for the region where opposite magnetic polarities are highly mixed. The third one, referred to as the separateness parameter, S l- f , considers the overall morphology. Further, G S and S l- f are photospheric, newly defined quick-look indicators of the polarity mix of the entire active region. The fourth method is tracking the temporal variation of small X-ray flares, their times of succession and their energies observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager instrument. All approaches yield specific pre-cursory signatures for the imminence of flares.

  5. Flare activity, sunspot motions, and the evolution of vector magnetic fields in Hale region 17244

    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.

  6. Discovery of flare activity on the dwarf M stars, GI 375 and GI 431

    Doyle, J.G.; Mathioudakis, M.; Panagi, P.M.; Butler, C.J. (Armagh Observatory, (IE))

    1990-12-01

    Optical and infrared photometry plus spectroscopic data is present for two new flare stars, GI 375 and GI 431. Both of these stars have the hydrogen Balmer lines strongly in emission. Several flares were detected on GI 375 implying a high level of flare activity. The H{alpha} surface flux of 1.0 x 10{sup 6} erg cm{sup -2}s{sup -1} for both stars is similar to that of other active flare stars. Fluxes are given for several of the higher Balmer lines.

  7. PRODUCTIVITY OF SOLAR FLARES AND MAGNETIC HELICITY INJECTION IN ACTIVE REGIONS

    Park, Sung-hong; Wang Haimin; Chae, Jongchul

    2010-01-01

    The main objective of this study is to better understand how magnetic helicity injection in an active region (AR) is related to the occurrence and intensity of solar flares. We therefore investigate the magnetic helicity injection rate and unsigned magnetic flux, as a reference. In total, 378 ARs are analyzed using SOHO/MDI magnetograms. The 24 hr averaged helicity injection rate and unsigned magnetic flux are compared with the flare index and the flare-productive probability in the next 24 hr following a measurement. In addition, we study the variation of helicity over a span of several days around the times of the 19 flares above M5.0 which occurred in selected strong flare-productive ARs. The major findings of this study are as follows: (1) for a sub-sample of 91 large ARs with unsigned magnetic fluxes in the range from (3-5) x 10 22 Mx, there is a difference in the magnetic helicity injection rate between flaring ARs and non-flaring ARs by a factor of 2; (2) the GOES C-flare-productive probability as a function of helicity injection displays a sharp boundary between flare-productive ARs and flare-quiet ones; (3) the history of helicity injection before all the 19 major flares displayed a common characteristic: a significant helicity accumulation of (3-45) x 10 42 Mx 2 during a phase of monotonically increasing helicity over 0.5-2 days. Our results support the notion that helicity injection is important in flares, but it is not effective to use it alone for the purpose of flare forecast. It is necessary to find a way to better characterize the time history of helicity injection as well as its spatial distribution inside ARs.

  8. ON THE NON-KOLMOGOROV NATURE OF FLARE-PRODUCTIVE SOLAR ACTIVE REGIONS

    Mandage, Revati S. [Physics and Astronomy Department, Rice University, 6100 Main MS-61, Houston, TX 77005-1827 (United States); McAteer, R. T. James, E-mail: mcateer@nmsu.edu [Department of Astronomy, New Mexico State University, MSC 4500, Las Cruces, NM 88001 (United States)

    2016-12-20

    A magnetic power spectral analysis is performed on 53 solar active regions, observed from 2011 August to 2012 July. Magnetic field data obtained from the Helioseismic and Magnetic Imager, inverted as Active Region Patches, are used to study the evolution of the magnetic power index as each region rotates across the solar disk. Active regions are classified based on the numbers and sizes of solar flares they produce in order to study the relationship between flare productivity and the magnetic power index. The choice of window size and inertial range plays a key role in determining the correct magnetic power index. The overall distribution of magnetic power indices has a range of 1.0–2.5. Flare-quiet regions peak at a value of 1.6. However, flare-productive regions peak at a value of 2.2. Overall, the histogram of the distribution of power indices of flare-productive active regions is well separated from flare-quiet active regions. Only 12% of flare-quiet regions exhibit an index greater than 2, whereas 90% of flare-productive regions exhibit an index greater than 2. Flare-quiet regions exhibit a high temporal variance (i.e., the index fluctuates between high and low values), whereas flare-productive regions maintain an index greater than 2 for several days. This shows the importance of including the temporal evolution of active regions in flare prediction studies, and highlights the potential of a 2–3 day prediction window for space weather applications.

  9. Flare activity on UV Ceti: visible and IUE observations

    Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

    1988-01-01

    Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU=2 mag but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings (∼ 100 km s -1 ). The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

  10. Flare activity on UV CETI: visible and IUE observations

    Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

    1988-06-01

    Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU = 2sup(m) but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings. The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

  11. Interplanetary medium and geomagnetic activity after compact flare triplets 1966-1981

    Ivanov, K.G.; Mikerina, N.V.; Pavlov, P.P.

    1986-01-01

    The interplanetary medium state and geomagnetic activity when the Earth is getting into this or that interplanetary disturbance zone after flare triplets, i.e. trains of three solar flares out of an active zone, are considered. There are the following conditionally differentiated zones in the interplanetary disturbance configuration: a forbidden (F), a perturbed (P) and a normal (N) zones of interplanetary disturbance. The interplanetary medium disturbances and geomagnetic activity after trains of three flares of class 2 and higher out of one of active zones depend on the following factors: the magnetic axis orientation of a bipolar group of active zone spots appeared after flares, time interval between the first and second flares in the train, flare intensity. The conditions of maximum disturbance occurrence pointed out. The interplanetary and geomagnetic disturbance intensity in the N zone is higher than that of the F and P zones (i.e. in the proximity of the great circle planes passing through the flares parallel with tha active zone magnetic axes), and it is higher after quasicompact rather than after compact triplets (i.e. it considerably grows when passing over the critical value of the time interval betwenn the first and second triplet flares, τ 12 =16 h)

  12. Magnetic Properties of Solar Active Regions that Govern Large Solar Flares and Eruptions

    Toriumi, Shin; Schrijver, Carolus J.; Harra, Louise; Hudson, Hugh S.; Nagashima, Kaori

    2017-08-01

    Strong flares and CMEs are often produced from active regions (ARs). In order to better understand the magnetic properties and evolutions of such ARs, we conducted statistical investigations on the SDO/HMI and AIA data of all flare events with GOES levels >M5.0 within 45 deg from the disk center for 6 years from May 2010 (from the beginning to the declining phase of solar cycle 24). Out of the total of 51 flares from 29 ARs, more than 80% have delta-sunspots and about 15% violate Hale’s polarity rule. We obtained several key findings including (1) the flare duration is linearly proportional to the separation of the flare ribbons (i.e., scale of reconnecting magnetic fields) and (2) CME-eruptive events have smaller sunspot areas. Depending on the magnetic properties, flaring ARs can be categorized into several groups, such as spot-spot, in which a highly-sheared polarity inversion line is formed between two large sunspots, and spot-satellite, where a newly-emerging flux next to a mature sunspot triggers a compact flare event. These results point to the possibility that magnetic structures of the ARs determine the characteristics of flares and CMEs. In the presentation, we will also show new results from the systematic flux emergence simulations of delta-sunspot formation and discuss the evolution processes of flaring ARs.

  13. Are Complex Magnetic Field Structures Responsible for the Confined X-class Flares in Super Active Region 12192?

    Zhang, Jun; Li, Ting; Chen, Huadong, E-mail: zjun@nao.cas.cn, E-mail: hdchen@nao.cas.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2017-08-10

    From 2014 October 19 to 27, six X-class flares occurred in super active region (AR) 12192. They were all confined flares and were not followed by coronal mass ejections. To examine the structures of the four flares close to the solar disk center from October 22 to 26, we firstly employ composite triple-time images in each flare process to display the stratified structure of these flare loops. The loop structures of each flare in both the lower (171 Å) and higher (131 Å) temperature channels are complex, e.g., the flare loops rooting at flare ribbons are sheared or twisted (enwound) together, and the complex structures were not destroyed during the flares. For the first flare, although the flare loop system appears as a spindle shape, we can estimate its structures from observations, with lengths ranging from 130 to 300 Mm, heights from 65 to 150 Mm, widths at the middle part of the spindle from 40 to 100 Mm, and shear angles from 16° to 90°. Moreover, the flare ribbons display irregular movements, such as the left ribbon fragments of the flare on October 22 sweeping a small region repeatedly, and both ribbons of the flare on October 26 moved along the same direction instead of separating from each other. These irregular movements also imply that the corresponding flare loops are complex, e.g., several sets of flare loops are twisted together. Although previous studies have suggested that the background magnetic fields prevent confined flares from erupting,based on these observations, we suggest that complex flare loop structures may be responsible for these confined flares.

  14. MAGNETIC PROPERTIES OF SOLAR ACTIVE REGIONS THAT GOVERN LARGE SOLAR FLARES AND ERUPTIONS

    Toriumi, Shin [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Schrijver, Carolus J. [Lockheed Martin Advanced Technology Center, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Harra, Louise K. [UCL-Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, RH5 6NT (United Kingdom); Hudson, Hugh [SUPA School of Physics and Astronomy, University of Glasgow (United Kingdom); Nagashima, Kaori, E-mail: shin.toriumi@nao.ac.jp [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2017-01-01

    Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim of understanding the magnetic properties that govern such flares and eruptions, we systematically survey all flare events with Geostationary Orbiting Environmental Satellite levels of ≥M5.0 within 45° from disk center between 2010 May and 2016 April. These criteria lead to a total of 51 flares from 29 ARs, for which we analyze the observational data obtained by the Solar Dynamics Observatory . More than 80% of the 29 ARs are found to exhibit δ -sunspots, and at least three ARs violate Hale’s polarity rule. The flare durations are approximately proportional to the distance between the two flare ribbons, to the total magnetic flux inside the ribbons, and to the ribbon area. From our study, one of the parameters that clearly determine whether a given flare event is CME-eruptive or not is the ribbon area normalized by the sunspot area, which may indicate that the structural relationship between the flaring region and the entire AR controls CME productivity. AR characterization shows that even X-class events do not require δ -sunspots or strong-field, high-gradient polarity inversion lines. An investigation of historical observational data suggests the possibility that the largest solar ARs, with magnetic flux of 2 × 10{sup 23} Mx, might be able to produce “superflares” with energies of the order of 10{sup 34} erg. The proportionality between the flare durations and magnetic energies is consistent with stellar flare observations, suggesting a common physical background for solar and stellar flares.

  15. Near Infrared Activity Close to the Crab Pulsar Correlated with Giant Gamma-ray Flares

    Rudy, Alexander R.; Max, Claire E.; Weisskopf, Martin C.

    2014-01-01

    We describe activity observed in the near-infrared correlated with a giant gamma-ray flare in the Crab Pulsar. The Crab Pulsar has been observed by the Fermi and AGILE satellites to flare for a period of 3 to 7 days, once every 1-1.5 years, increasing in brightness by a factor of 3-10 between 100MeV and 1GeV. We used Keck NIRC2 laser guide star adaptive optics imaging to observe the Crab Pulsar and environs before and during the March 2013 flare. We discuss the evidence for the knot as the location of the flares, and the theoretical implications of these observations. Ongoing target-of-opportunity programs hope to confirm this correlation for future flares.

  16. CONNECTING FLARES AND TRANSIENT MASS-LOSS EVENTS IN MAGNETICALLY ACTIVE STARS

    Osten, Rachel A. [Space Telescope Science Institute 3700 San Martin Drive, Baltimore, MD 21218 (United States); Wolk, Scott J., E-mail: osten@stsci.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138 (United States)

    2015-08-10

    We explore the ramification of associating the energetics of extreme magnetic reconnection events with transient mass-loss in a stellar analogy with solar eruptive events. We establish energy partitions relative to the total bolometric radiated flare energy for different observed components of stellar flares and show that there is rough agreement for these values with solar flares. We apply an equipartition between the bolometric radiated flare energy and kinetic energy in an accompanying mass ejection, seen in solar eruptive events and expected from reconnection. This allows an integrated flare rate in a particular waveband to be used to estimate the amount of associated transient mass-loss. This approach is supported by a good correspondence between observational flare signatures on high flaring rate stars and the Sun, which suggests a common physical origin. If the frequent and extreme flares that young solar-like stars and low-mass stars experience are accompanied by transient mass-loss in the form of coronal mass ejections, then the cumulative effect of this mass-loss could be large. We find that for young solar-like stars and active M dwarfs, the total mass lost due to transient magnetic eruptions could have significant impacts on disk evolution, and thus planet formation, and also exoplanet habitability.

  17. THE CONFINED X-CLASS FLARES OF SOLAR ACTIVE REGION 2192

    Thalmann, J. K.; Su, Y.; Temmer, M.; Veronig, A. M., E-mail: julia.thalmann@uni-graz.at [Institute of Physics/IGAM, University of Graz, Universitätsplatz 5/II, 8010 Graz (Austria)

    2015-03-10

    The unusually large active region (AR) NOAA 2192, observed in 2014 October, was outstanding in its productivity of major two-ribbon flares without coronal mass ejections. On a large scale, a predominantly north–south oriented magnetic system of arcade fields served as a strong top and lateral confinement for a series of large two-ribbon flares originating from the core of the AR. The large initial separation of the flare ribbons, together with an almost absent growth in ribbon separation, suggests a confined reconnection site high up in the corona. Based on a detailed analysis of the confined X1.6 flare on October 22, we show how exceptional the flaring of this AR was. We provide evidence for repeated energy release, indicating that the same magnetic field structures were repeatedly involved in magnetic reconnection. We find that a large number of electrons was accelerated to non-thermal energies, revealing a steep power-law spectrum, but that only a small fraction was accelerated to high energies. The total non-thermal energy in electrons derived (on the order of 10{sup 25} J) is considerably higher than that in eruptive flares of class X1, and corresponds to about 10% of the excess magnetic energy present in the active-region corona.

  18. A method for untriggered time-dependent searches for multiple flares from neutrino point sources

    Gora, D.; Bernardini, E.; Cruz Silva, A.H.

    2011-04-01

    A method for a time-dependent search for flaring astrophysical sources which can be potentially detected by large neutrino experiments is presented. The method uses a time-clustering algorithm combined with an unbinned likelihood procedure. By including in the likelihood function a signal term which describes the contribution of many small clusters of signal-like events, this method provides an effective way for looking for weak neutrino flares over different time-scales. The method is sensitive to an overall excess of events distributed over several flares which are not individually detectable. For standard cases (one flare) the discovery potential of the method is worse than a standard time-dependent point source analysis with unknown duration of the flare by a factor depending on the signal-to-background level. However, for flares sufficiently shorter than the total observation period, the method is more sensitive than a time-integrated analysis. (orig.)

  19. A method for untriggered time-dependent searches for multiple flares from neutrino point sources

    Gora, D. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Institute of Nuclear Physics PAN, Cracow (Poland); Bernardini, E.; Cruz Silva, A.H. [Institute of Nuclear Physics PAN, Cracow (Poland)

    2011-04-15

    A method for a time-dependent search for flaring astrophysical sources which can be potentially detected by large neutrino experiments is presented. The method uses a time-clustering algorithm combined with an unbinned likelihood procedure. By including in the likelihood function a signal term which describes the contribution of many small clusters of signal-like events, this method provides an effective way for looking for weak neutrino flares over different time-scales. The method is sensitive to an overall excess of events distributed over several flares which are not individually detectable. For standard cases (one flare) the discovery potential of the method is worse than a standard time-dependent point source analysis with unknown duration of the flare by a factor depending on the signal-to-background level. However, for flares sufficiently shorter than the total observation period, the method is more sensitive than a time-integrated analysis. (orig.)

  20. Endodontic flare-ups: comparison of incidence between single and multiple visits procedures in patients attending a Nigerian teaching hospital.

    Oginni, Ao; Udoye, C I

    2004-12-01

    The present study was performed to compare the incidence of endodontic flare ups in single with multiple visits treatment procedures, to establish the relationship between pre-operative and post obturation pain in patients attending for endodontic therapy in a Nigerian teaching Hospital. Patients were randomly assigned to either single visit or multiple visits group. Data collected at root canal treatment appointment and recall visits (1st, 7th and 30th day post obturation) include pulp vitality status, the presence or absence of pre-operative pain, presence and degree of post obturation pain. Presence of endodontic flare-ups (defined as either patient's report of pain not controlled with over the counter medication and or increasing swelling). The compiled data were analyzed using chi-square where applicable. P level endodontic flare-ups (8.1 %) were recorded in the multiple visits group compared to 19 (18,3%) flare-ups for the single visit group, P = 0.02. For both single and multiple visits procedures, there were statistically significant correlations between pre operative and post obturation pain (P = 0.002 and P = 0.0004 respectively). Teeth with vital pulps reported the lowest frequency of post obturation pain (48.8%), while those with non vital pulps were found to have the highest frequency oh post obturation pain (50,3%), P = 0.9. Although the present study reported higher incidences for post obturation pain and flare-ups following the single visit procedures, single visit endodontic therapy has been shown to be a safe and effective alternative to multiple visits treatment.

  1. Comparison of microdose flare-up and antagonist multiple-dose protocols for poor-responder patients: a randomized study.

    Demirol, Aygul; Gurgan, Timur

    2009-08-01

    To compare the efficacy of the microdose flare-up and multiple-dose antagonist protocols for poor-responder patients in intracytoplasmic sperm injection-ET cycles. A randomized, prospective study. Center for assisted reproductive technology in Turkey. Ninety patients with poor ovarian response in a minimum of two previous IVF cycles. All women were prospectively randomized into two groups by computer-assisted randomization. The patients in group 1 were stimulated according to the microdose flare-up protocol (n = 45), while the patients in group 2 were stimulated according to antagonist multiple-dose protocol (n = 45). The mean number of mature oocytes retrieved was the primary outcome measure, and fertilization rate, implantation rate per embryo, and clinical pregnancy rates were secondary outcome measures. The mean age of the women, the mean duration of infertility, basal FSH level, and the number of previous IVF cycles were similar in both groups. The total gonadotropin dose used was significantly higher in group 2, while the number of oocytes retrieved was significantly greater in group 1. Although the fertilization and clinical pregnancy rates were nonsignificantly higher in group 1 compared with group 2, the implantation rate was significantly higher in the microdose flare-up group than in the multiple-dose antagonist group (22% vs. 11%). The microdose flare-up protocol seems to have a better outcome in poor-responder patients, with a significantly higher mean number of mature oocytes retrieved and higher implantation rate.

  2. WHY IS A FLARE-RICH ACTIVE REGION CME-POOR?

    Liu, Lijuan; Wang, Yuming; Shen, Chenglong; Ye, Pinzhong; Liu, Rui; Chen, Jun; Zhang, Quanhao; Wang, S. [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang, Jingxiu, E-mail: ymwang@ustc.edu.cn, E-mail: ljliu@mail.ustc.edu.cn [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2016-08-01

    Solar active regions (ARs) are the major sources of two of the most violent solar eruptions, namely flares and coronal mass ejections (CMEs). The largest AR in the past 24 years, NOAA AR 12192, which crossed the visible disk from 2014 October 17 to 30, unusually produced more than one hundred flares, including 32 M-class and 6 X-class ones, but only one small CME. Flares and CMEs are believed to be two phenomena in the same eruptive process. Why is such a flare-rich AR so CME-poor? We compared this AR with other four ARs; two were productive in both and two were inert. The investigation of the photospheric parameters based on the SDO /HMI vector magnetogram reveals that the flare-rich AR 12192, as with the other two productive ARs, has larger magnetic flux, current, and free magnetic energy than the two inert ARs but, in contrast to the two productive ARs, it has no strong, concentrated current helicity along both sides of the flaring neutral line, indicating the absence of a mature magnetic structure consisting of highly sheared or twisted field lines. Furthermore, the decay index above the AR 12192 is relatively low, showing strong constraint. These results suggest that productive ARs are always large and have enough current and free energy to power flares, but whether or not a flare is accompanied by a CME is seemingly related to (1) the presence of a mature sheared or twisted core field serving as the seed of the CME, or (2) a weak enough constraint of the overlying arcades.

  3. 8-12 GHz Radio Observations of Flare Activity On M dwarf CN Leo

    Wofford, Alia; Villadsen, Jackie; Quintana, Elisa; Barclay, Thomas; Thackeray, Beverly

    2018-01-01

    Red dwarfs are cool stars that make up 70% of all stars. Red dwarfs can be utilized to detect potentially habitable planets but they have particularly strong magnetic activity that can be detrimental to orbiting planets’ atmospheres and habitability. A coronal mass ejection (CME) is an eruption of magnetized plasma from the star that is ejected into the interplanetary medium which can erode a planet’s atmosphere daily. Based on the sun CMEs are expected to produce very bright radio bursts along with optical flares. We are using M dwarf CN Leo, a well studied flare star that was in the K2 campaign field in summer 2017, as a template to understand the relationship between radio and optical flares and the space weather conditions impacting M dwarf planets. Using radio frequencies ranging from 0.22 GHz-12 GHz we search for simultaneous radio bursts and optical flares to infer if CMEs, flares or aurorae are occurring on the star. I will present the 8-12 GHz radio data from eight 1.5-hour observations with simultaneous optical data. CN Leo produced a bright non-thermal radio flare that lasted approximately for a day during two consecutive observations, with a gyrosynchrotron emission mechanism.

  4. HOW DID A MAJOR CONFINED FLARE OCCUR IN SUPER SOLAR ACTIVE REGION 12192?

    Jiang, Chaowei; Feng, Xueshang [SIGMA Weather Group, State Key Laboratory for Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China); Wu, S. T.; Hu, Qiang [Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Yurchyshyn, Vasyl; Wang, Haiming, E-mail: cwjiang@spaceweather.ac.cn [Big Bear Solar Observatory, New Jersey Institute of Technology, 40386 North Shore Lane, Big Bear City, CA 92314 (United States)

    2016-09-01

    We study the physical mechanism of a major X-class solar flare that occurred in the super NOAA active region (AR) 12192 using data-driven numerical magnetohydrodynamic (MHD) modeling complemented with observations. With the evolving magnetic fields observed at the solar surface as bottom boundary input, we drive an MHD system to evolve self-consistently in correspondence with the realistic coronal evolution. During a two-day time interval, the modeled coronal field has been slowly stressed by the photospheric field evolution, which gradually created a large-scale coronal current sheet, i.e., a narrow layer with intense current, in the core of the AR. The current layer was successively enhanced until it became so thin that a tether-cutting reconnection between the sheared magnetic arcades was set in, which led to a flare. The modeled reconnecting field lines and their footpoints match well the observed hot flaring loops and the flare ribbons, respectively, suggesting that the model has successfully “reproduced” the macroscopic magnetic process of the flare. In particular, with simulation, we explained why this event is a confined eruption—the consequence of the reconnection is a shared arcade instead of a newly formed flux rope. We also found a much weaker magnetic implosion effect compared to many other X-class flares.

  5. Assessment of respiratory disorders in relation to solution gas flaring activities in Alberta

    1998-02-01

    A study was conducted by Alberta Health to address the issue of whether or not flaring of solution gas has a negative impact on human health. The Flaring Working Group of the Clean Air Strategic Alliance initiated this study which focused on the assessment of the relationship between human health disorders (such as asthma, bronchitis, pneumonia and upper respiratory infections) and solution gas flaring activities in rural, urban and aboriginal populations. The personal exposure to flaring emissions was estimated by physical proximity to the source of emissions. A small area was studied in which geographical variations in human health disorders were compared to geographical variations of socioeconomic and environmental factors. Data was gathered from 1989 to 1996 to evaluate long term average conditions and changes over the time period investigated. Notwithstanding physicians' claims for increased rates of respiratory infections and hospitalization attributed to solution gas flaring, the study found no evidence linking respiratory infections and solution gas flaring. This was the conclusion regardless of the measure of health outcomes, the rural-urban status, ethnicity, or age. Nevertheless, the study recommended identification of bio-markers of exposure and effect reflective of the compounds of interest, and the development of a responsive and comprehensive geographic information database that would allow data linkage at all geographic levels for different periods of time. refs., 10 tabs., 15 figs., 1 appendix

  6. FORMATION AND ERUPTION OF A FLUX ROPE FROM THE SIGMOID ACTIVE REGION NOAA 11719 AND ASSOCIATED M6.5 FLARE: A MULTI-WAVELENGTH STUDY

    Joshi, Bhuwan; Kushwaha, Upendra; Dhara, Sajal Kumar [Udaipur Solar Observatory, Physical Research Laboratory, Udaipur 313001 (India); Veronig, Astrid M. [Kanzelhöhe Observatory/Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Shanmugaraju, A. [Department of Physics, Arul Anandhar College, Karumathur, Tamilnadu 625514 (India); Moon, Yong-Jae, E-mail: bhuwan@prl.res.in [School of Space Research, Kyung Hee University, Yongin, Gyeonggi-Do, 446-701 (Korea, Republic of)

    2017-01-01

    We investigate the formation, activation, and eruption of a flux rope (FR) from the sigmoid active region NOAA 11719 by analyzing E(UV), X-ray, and radio measurements. During the pre-eruption period of ∼7 hr, the AIA 94 Å images reveal the emergence of a coronal sigmoid through the interaction between two J-shaped bundles of loops, which proceeds with multiple episodes of coronal loop brightenings and significant variations in the magnetic flux through the photosphere. These observations imply that repetitive magnetic reconnections likely play a key role in the formation of the sigmoidal FR in the corona and also contribute toward sustaining the temperature of the FR higher than that of the ambient coronal structures. Notably, the formation of the sigmoid is associated with the fast morphological evolution of an S-shaped filament channel in the chromosphere. The sigmoid activates toward eruption with the ascent of a large FR in the corona, which is preceded by the decrease in photospheric magnetic flux through the core flaring region, suggesting tether-cutting reconnection as a possible triggering mechanism. The FR eruption results in a two-ribbon M6.5 flare with a prolonged rise phase of ∼21 minutes. The flare exhibits significant deviation from the standard flare model in the early rise phase, during which a pair of J-shaped flare ribbons form and apparently exhibit converging motions parallel to the polarity inversion line, which is further confirmed by the motions of hard X-ray footpoint sources. In the later stages, the flare follows the standard flare model and the source region undergoes a complete sigmoid-to-arcade transformation.

  7. The influence of active region information on the prediction of solar flares: an empirical model using data mining

    M. Núñez

    2005-11-01

    Full Text Available Predicting the occurrence of solar flares is a challenge of great importance for many space weather scientists and users. We introduce a data mining approach, called Behavior Pattern Learning (BPL, for automatically discovering correlations between solar flares and active region data, in order to predict the former. The goal of BPL is to predict the interval of time to the next solar flare and provide a confidence value for the associated prediction. The discovered correlations are described in terms of easy-to-read rules. The results indicate that active region dynamics is essential for predicting solar flares.

  8. Photospheric Spots and Flare on the Active Dwarf Star FR Cnc

    Kozhevnikova, A. V.; Kozhevnikov, V. P.; Alekseev, I. Yu.

    2018-03-01

    We perform analysis of new BVRI photometry of young active dwarf star FR Cnc (K7V), obtained at Kourovka astronomical observatory of Ural Federal University with the help of multichannel electrophotometer in February 2010. The lightcurve displays sinusoidal rotation modulation with the amplitude of 0m.15 in V band. Reddening of the brightness at the photometric minimum confirms that this modulation is caused by cold photospheric spots. An analysis of the spottedness distribution in terms of a zonal model based on our own and published data shows that the spots are localized at lower and middle latitudes from 47° to 56°, occupy 10-21% of the star's area, and are colder than the photosphere by 1650 K. A flare was detected on February 3, 2010, at a time corresponding to HJD=2455231. 3136. A maximum amplitude of 0m.11 was observed in the B band, the amplitudes in the V, R, and I bands were 0m.04, 0m.03, and 0m.02, respectively, and the duration of the flare was 32.5 min. It was noted that the flare occurred near the maximum spottedness of the star. The calculated total energy of the flare was 2.4·1033 and 1.3·1033 erg in the B and V bands, respectively. The flare was found to have an afterglow, with an overall increase in the star's brightness by 0m.02 in the B band after the flare compared to the pre-flare level.

  9. Block-induced Complex Structures Building the Flare-productive Solar Active Region 12673

    Yang, Shuhong; Zhang, Jun [CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Zhu, Xiaoshuai [Max-Planck Institute for Solar System Research, D-37077 Göttingen (Germany); Song, Qiao, E-mail: shuhongyang@nao.cas.cn [Key Laboratory of Space Weather, National Center for Space Weather, China Meteorological Administration, Beijing 100081 (China)

    2017-11-10

    Solar active region (AR) 12673 produced 4 X-class, 27 M-class, and numerous lower-class flares during its passage across the visible solar disk in 2017 September. Our study is to answer the questions why this AR was so flare-productive and how the X9.3 flare, the largest one of the past decade, took place. We find that there was a sunspot in the initial several days, and then two bipolar regions emerged nearby it successively. Due to the standing of the pre-existing sunspot, the movement of the bipoles was blocked, while the pre-existing sunspot maintained its quasi-circular shaped umbra only with the disappearance of a part of penumbra. Thus, the bipolar patches were significantly distorted, and the opposite polarities formed two semi-circular shaped structures. After that, two sequences of new bipolar regions emerged within the narrow semi-circular zone, and the bipolar patches separated along the curved channel. The new bipoles sheared and interacted with the previous ones, forming a complex topological system, during which numerous flares occurred. At the highly sheared region, a great deal of free energy was accumulated. On September 6, one negative patch near the polarity inversion line began to rapidly rotate and shear with the surrounding positive fields, and consequently the X9.3 flare erupted. Our results reveal that the block-induced complex structures built the flare-productive AR and the X9.3 flare was triggered by an erupting filament due to the kink instability. To better illustrate this process, a block-induced eruption model is proposed for the first time.

  10. The prevalence of postoperative pain and flare-up in single- and multiple-visit endodontic treatment: a systematic review.

    Sathorn, C; Parashos, P; Messer, H

    2008-02-01

    The aim of this systematic review was to assess the evidence regarding postoperative pain and flare-up of single- or multiple-visit root canal treatment. CENTRAL, MEDLINE and EMBASE databases were searched. Reference lists from identified articles were scanned. A forward search was undertaken on the authors of the identified articles. Papers that had cited these articles were also identified through Science Citation Index to identify potentially relevant subsequent primary research. The included clinical studies compared the prevalence/severity of postoperative pain or flare-up in single- and multiple-visit root canal treatment. Data in those studies were extracted independently. Sixteen studies fitted the inclusion criteria in the review, with sample size varying from 60 to 1012 cases. The prevalence of postoperative pain ranged from 3% to 58%. The heterogeneity amongst included studies was far too great to conduct meta-analysis and yield meaningful results. Compelling evidence indicating a significantly different prevalence of postoperative pain/flare-up of either single- or multiple-visit root canal treatment is lacking.

  11. Relation of flare activity to the approach and separation of sunspots in an active region and to its magnetic properties

    Markova, E.

    1978-01-01

    The relation between the flare activity of active regions within the scope of a large complex and the magnetic gradients of these active regions and their daily variations is investigated in the interval of the exceptionally high flare activity occurring in June 1970. New indices, characterizing the active region, were defined, e.g., the instantaneous sunspot-area density and the instantaneous sunspot-number density. These indices were determined on the basis of measurements of the surface containing all sunspots of the complex of active regions enclosed by an envelope. An attempt was made to substitute the surface in the relation for the individual indices by distance. The daily variations of these indices were again compared with the flare activity and some mutual relations were derived. (author)

  12. Postoperative Pain and Flare-Ups: Comparison of Incidence Between Single and Multiple Visit Pulpectomy in Primary Molars

    Gowda, Subhadra Halemane Nagaraj

    2017-01-01

    Introduction Endodontic treatment performed in either single- or multiple visit can be followed by numerous short- and long term complications. One of the short term complications include postoperative pain and flare–ups. The ability to predict its prevalence and forewarn the patient may go some way towards enabling coping strategies and help dentist in pain management treatment decisions Aim To compare the incidence and intensity of postoperative pain and flare-ups between single- and multiple visit pulpectomy in primary molars. Also, to correlate the preoperative status of the pulp to postoperative pain and flare-ups. Materials and Methods Eighty primary molars indicated for pulpectomy were included in the study and divided into two groups. Tooth treated and preoperative status of the pulp vitality was recorded. All the conventional steps in pulpectomy were followed. Teeth in Group 1 (single visit pulpectomy) were obturated on the same visit. Teeth in Group 2 (multiple visit pulpectomy) were obturated in the subsequent appointment. The recording of postoperative pain, flare-ups, use of medication were done after 24 hours, seven days and one month. Results Four cases in both the groups reported postoperative pain (10%) at 24 hour recall, p=0.74. One flare-up (2.5%) was recorded in each group p=0.67. None of the patients reported pain at seventh day and one month recall. Postoperative pain was recorded in five non-vital teeth (13.5%) and three vital teeth (6.9%). However, it was statistically not significant p=0.53. Conclusion From the perspective of our study there was a low incidence of postoperative pain. The majority of patients in both groups reported no pain or only minimal pain within 24 hours of treatment. There were no differences between single- and multi visit treatment protocols with respect to the incidence of postoperative pain. No significant correlation could be found between pulp vitality and the incidence of postoperative pain. PMID:28511499

  13. A STATISTICAL STUDY OF FLARE PRODUCTIVITY ASSOCIATED WITH SUNSPOT PROPERTIES IN DIFFERENT MAGNETIC TYPES OF ACTIVE REGIONS

    Yang, Ya-Hui [Institute of Space Science, National Central University, Jhongli 32001, Taiwan (China); Hsieh, Min-Shiu [Geophysical Institute, University of Alaska Fairbanks, AK 99775-7320 (United States); Yu, Hsiu-Shan [Center for Astrophysics and Space Sciences, University of California San Diego, CA 92093 (United States); Chen, P. F., E-mail: yhyang@jupiter.ss.ncu.edu.tw, E-mail: mhsieh2@alaska.edu, E-mail: hsyu@ucsd.edu, E-mail: chenpf@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China)

    2017-01-10

    It is often believed that intense flares preferentially originate from the large-size active regions (ARs) with strong magnetic fields and complex magnetic configurations. This work investigates the dependence of flare activity on the AR properties and clarifies the influence of AR magnetic parameters on the flare productivity, based on two data sets of daily sunspot and flare information as well as the GOES soft X-ray measurements and HMI vector magnetograms. By considering the evolution of magnetic complexity, we find that flare behaviors are quite different in the short- and long-lived complex ARs and the ARs with more complex magnetic configurations are likely to host more impulsive and intense flares. Furthermore, we investigate several magnetic quantities and perform the two-sample Kolmogorov–Smirnov test to examine the similarity/difference between two populations in different types of ARs. Our results demonstrate that the total source field strength on the photosphere has a good correlation with the flare activity in complex ARs. It is noted that intense flares tend to occur at the regions of strong source field in combination with an intermediate field-weighted shear angle. This result implies that the magnetic free energy provided by a complex AR could be high enough to trigger a flare eruption even with a moderate magnetic shear on the photosphere. We thus suggest that the magnetic free energy represented by the source field rather than the photospheric magnetic complexity is a better quantity to characterize the flare productivity of an AR, especially for the occurrence of intense flares.

  14. TIME EVOLUTION OF CORONAL MAGNETIC HELICITY IN THE FLARING ACTIVE REGION NOAA 10930

    Park, Sung-Hong; Jing, Ju; Wang Haimin; Chae, Jongchul; Tan, Changyi

    2010-01-01

    To study the three-dimensional (3D) magnetic field topology and its long-term evolution associated with the X3.4 flare of 2006 December 13, we investigate the coronal relative magnetic helicity in the flaring active region (AR) NOAA 10930 during the time period of December 8-14. The coronal helicity is calculated based on the 3D nonlinear force-free magnetic fields reconstructed by the weighted optimization method of Wiegelmann, and is compared with the amount of helicity injected through the photospheric surface of the AR. The helicity injection is determined from the magnetic helicity flux density proposed by Pariat et al. using Solar and Heliospheric Observatory/Michelson Doppler Imager magnetograms. The major findings of this study are the following. (1) The time profile of the coronal helicity shows a good correlation with that of the helicity accumulation by injection through the surface. (2) The coronal helicity of the AR is estimated to be -4.3 x 10 43 Mx 2 just before the X3.4 flare. (3) This flare is preceded not only by a large increase of negative helicity, -3.2 x 10 43 Mx 2 , in the corona over ∼1.5 days but also by noticeable injections of positive helicity through the photospheric surface around the flaring magnetic polarity inversion line during the time period of the channel structure development. We conjecture that the occurrence of the X3.4 flare is involved with the positive helicity injection into an existing system of negative helicity.

  15. QUANTIFYING THE TOPOLOGY AND EVOLUTION OF A MAGNETIC FLUX ROPE ASSOCIATED WITH MULTI-FLARE ACTIVITIES

    Yang, Kai; Guo, Yang; Ding, M. D.

    2016-01-01

    Magnetic flux ropes (MFRs) play an important role in solar activities. The quantitative assessment of the topology of an MFR and its evolution is crucial for a better understanding of the relationship between the MFR and associated activities. In this paper, we investigate the magnetic field of active region (AR) 12017 from 2014 March 28–29, during which time 12 flares were triggered by intermittent eruptions of a filament (either successful or confined). Using vector magnetic field data from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory , we calculate the magnetic energy and helicity injection in the AR, and extrapolate the 3D magnetic field with a nonlinear force-free field model. From the extrapolations, we find an MFR that is cospatial with the filament. We further determine the configuration of this MFR from the closed quasi-separatrix layer (QSL) around it. Then, we calculate the twist number and the magnetic helicity for the field lines composing the MFR. The results show that the closed QSL structure surrounding the MFR becomes smaller as a consequence of flare occurrence. We also find that the flares in our sample are mainly triggered by kink instability. Moreover, the twist number varies more sensitively than other parameters with the occurrence of flares.

  16. Quantifying the Topology and Evolution of a Magnetic Flux Rope Associated with Multi-flare Activities

    Yang, Kai; Guo, Yang; Ding, M. D.

    2016-06-01

    Magnetic flux ropes (MFRs) play an important role in solar activities. The quantitative assessment of the topology of an MFR and its evolution is crucial for a better understanding of the relationship between the MFR and associated activities. In this paper, we investigate the magnetic field of active region (AR) 12017 from 2014 March 28-29, during which time 12 flares were triggered by intermittent eruptions of a filament (either successful or confined). Using vector magnetic field data from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, we calculate the magnetic energy and helicity injection in the AR, and extrapolate the 3D magnetic field with a nonlinear force-free field model. From the extrapolations, we find an MFR that is cospatial with the filament. We further determine the configuration of this MFR from the closed quasi-separatrix layer (QSL) around it. Then, we calculate the twist number and the magnetic helicity for the field lines composing the MFR. The results show that the closed QSL structure surrounding the MFR becomes smaller as a consequence of flare occurrence. We also find that the flares in our sample are mainly triggered by kink instability. Moreover, the twist number varies more sensitively than other parameters with the occurrence of flares.

  17. QUANTIFYING THE TOPOLOGY AND EVOLUTION OF A MAGNETIC FLUX ROPE ASSOCIATED WITH MULTI-FLARE ACTIVITIES

    Yang, Kai; Guo, Yang; Ding, M. D., E-mail: dmd@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China)

    2016-06-20

    Magnetic flux ropes (MFRs) play an important role in solar activities. The quantitative assessment of the topology of an MFR and its evolution is crucial for a better understanding of the relationship between the MFR and associated activities. In this paper, we investigate the magnetic field of active region (AR) 12017 from 2014 March 28–29, during which time 12 flares were triggered by intermittent eruptions of a filament (either successful or confined). Using vector magnetic field data from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory , we calculate the magnetic energy and helicity injection in the AR, and extrapolate the 3D magnetic field with a nonlinear force-free field model. From the extrapolations, we find an MFR that is cospatial with the filament. We further determine the configuration of this MFR from the closed quasi-separatrix layer (QSL) around it. Then, we calculate the twist number and the magnetic helicity for the field lines composing the MFR. The results show that the closed QSL structure surrounding the MFR becomes smaller as a consequence of flare occurrence. We also find that the flares in our sample are mainly triggered by kink instability. Moreover, the twist number varies more sensitively than other parameters with the occurrence of flares.

  18. Flare Characteristics from X-ray Light Curves

    Gryciuk, M.; Siarkowski, M.; Sylwester, J.; Gburek, S.; Podgorski, P.; Kepa, A.; Sylwester, B.; Mrozek, T.

    2017-06-01

    A new methodology is given to determine basic parameters of flares from their X-ray light curves. Algorithms are developed from the analysis of small X-ray flares occurring during the deep solar minimum of 2009, between Solar Cycles 23 and 24, observed by the Polish Solar Photometer in X-rays (SphinX) on the Complex Orbital Observations Near-Earth of Activity of the Sun-Photon (CORONAS- Photon) spacecraft. One is a semi-automatic flare detection procedure that gives start, peak, and end times for single ("elementary") flare events under the assumption that the light curve is a simple convolution of a Gaussian and exponential decay functions. More complex flares with multiple peaks can generally be described by a sum of such elementary flares. Flare time profiles in the two energy ranges of SphinX (1.16 - 1.51 keV, 1.51 - 15 keV) are used to derive temperature and emission measure as a function of time during each flare. The result is a comprehensive catalogue - the SphinX Flare Catalogue - which contains 1600 flares or flare-like events and is made available for general use. The methods described here can be applied to observations made by Geosynchronous Operational Environmental Satellites (GOES), the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and other broad-band spectrometers.

  19. FLARES AND THEIR UNDERLYING MAGNETIC COMPLEXITY

    Engell, Alexander J.; Golub, Leon; Korreck, Kelly; Siarkowski, Marek; Gryciuk, Magda; Sylwester, Janusz; Sylwester, Barbara; Cirtain, Jonathan

    2011-01-01

    SphinX (Solar PHotometer IN X-rays), a full-disk-integrated spectrometer, observed 137 flare-like/transient events with active region (AR) 11024 being the only AR on disk. The Hinode X-Ray Telescope (XRT) and Solar Optical Telescope observe 67 of these events and identified their location from 12:00 UT on July 3 through 24:00 UT 2009 July 7. We find that the predominant mechanisms for flares observed by XRT are (1) flux cancellation and (2) the shearing of underlying magnetic elements. Point- and cusp-like flare morphologies seen by XRT all occur in a magnetic environment where one polarity is impeded by the opposite polarity and vice versa, forcing the flux cancellation process. The shearing is either caused by flux emergence at the center of the AR and separation of polarities along a neutral line or by individual magnetic elements having a rotational motion. Both mechanisms are observed to contribute to single- and multiple-loop flares. We observe that most loop flares occur along a large portion of a polarity inversion line. Point- and cusp-like flares become more infrequent as the AR becomes organized with separation of the positive and negative polarities. SphinX, which allows us to identify when these flares occur, provides us with a statistically significant temperature and emission scaling law for A and B class flares: EM = 6.1 x 10 33 T 1.9±0.1 .

  20. MAG4 versus alternative techniques for forecasting active region flare productivity

    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

  1. Simulating flaring events in complex active regions driven by observed magnetograms

    Dimitropoulou, M.; Isliker, H.; Vlahos, L.; Georgoulis, M. K.

    2011-05-01

    Context. We interpret solar flares as events originating in active regions that have reached the self organized critical state, by using a refined cellular automaton model with initial conditions derived from observations. Aims: We investigate whether the system, with its imposed physical elements, reaches a self organized critical state and whether well-known statistical properties of flares, such as scaling laws observed in the distribution functions of characteristic parameters, are reproduced after this state has been reached. Methods: To investigate whether the distribution functions of total energy, peak energy and event duration follow the expected scaling laws, we first applied a nonlinear force-free extrapolation that reconstructs the three-dimensional magnetic fields from two-dimensional vector magnetograms. We then locate magnetic discontinuities exceeding a threshold in the Laplacian of the magnetic field. These discontinuities are relaxed in local diffusion events, implemented in the form of cellular automaton evolution rules. Subsequent loading and relaxation steps lead the system to self organized criticality, after which the statistical properties of the simulated events are examined. Physical requirements, such as the divergence-free condition for the magnetic field vector, are approximately imposed on all elements of the model. Results: Our results show that self organized criticality is indeed reached when applying specific loading and relaxation rules. Power-law indices obtained from the distribution functions of the modeled flaring events are in good agreement with observations. Single power laws (peak and total flare energy) are obtained, as are power laws with exponential cutoff and double power laws (flare duration). The results are also compared with observational X-ray data from the GOES satellite for our active-region sample. Conclusions: We conclude that well-known statistical properties of flares are reproduced after the system has

  2. Triggering Process of the X1.0 Three-ribbon Flare in the Great Active Region NOAA 12192

    Bamba, Yumi [Institute of Space and Astronautical Science (ISAS)/Japan Aerospace Exploration Agency (JAXA) 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Inoue, Satoshi; Kusano, Kanya; Shiota, Daikou, E-mail: y-bamba@nagoya-u.jp [Institute for Space-Earth Environmental Research (ISEE)/Nagoya University Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan)

    2017-04-01

    The solar magnetic field in a flare-producing active region (AR) is much more complicated than theoretical models, which assume a very simple magnetic field structure. The X1.0 flare, which occurred in AR 12192 on 2014 October 25, showed a complicated three-ribbon structure. To clarify the trigger process of the flare and to evaluate the applicability of a simple theoretical model, we analyzed the data from Hinode /Solar Optical Telescope and the Solar Dynamics Observatory /Helioseismic and Magnetic Imager, Atmospheric Imaging Assembly. We investigated the spatio-temporal correlation between the magnetic field structures, especially the non-potentiality of the horizontal field, and the bright structures in the solar atmosphere. As a result, we determined that the western side of the positive polarity, which is intruding on a negative polarity region, is the location where the flare was triggered. This is due to the fact that the sign of the magnetic shear in that region was opposite that of the major shear of the AR, and the significant brightenings were observed over the polarity inversion line (PIL) in that region before flare onset. These features are consistent with the recently proposed flare-trigger model that suggests that small reversed shear (RS) magnetic disturbances can trigger solar flares. Moreover, we found that the RS field was located slightly off the flaring PIL, contrary to the theoretical prediction. We discuss the possibility of an extension of the RS model based on an extra numerical simulation. Our result suggests that the RS field has a certain flexibility for displacement from a highly sheared PIL, and that the RS field triggers more flares than we expected.

  3. EVOLUTION OF CURRENTS OF OPPOSITE SIGNS IN THE FLARE-PRODUCTIVE SOLAR ACTIVE REGION NOAA 10930

    Ravindra, B.; Venkatakrishnan, P.; Tiwari, Sanjiv Kumar; Bhattacharyya, R.

    2011-01-01

    Analysis of a time series of high spatial resolution vector magnetograms of the active region NOAA 10930 available from the Solar Optical Telescope SpectroPolarimeter on board Hinode revealed that there is a mixture of upward and downward currents in the two footpoints of an emerging flux rope. The flux emergence rate is almost the same in both the polarities. We observe that along with an increase in magnetic flux, the net current in each polarity increases initially for about three days after which it decreases. This net current is characterized by having exactly opposite signs in each polarity while its magnitude remains almost the same most of the time. The decrease of the net current in both the polarities is due to the increase of current having a sign opposite to that of the net current. The dominant current, with the same sign as the net current, is seen to increase first and then decreases during the major X-class flares. Evolution of non-dominant current appears to be a necessary condition for flare initiation. The above observations can be plausibly explained in terms of the superposition of two different force-free states resulting in a non-zero Lorentz force in the corona. This Lorentz force then pushes the coronal plasma and might facilitate the magnetic reconnection required for flares. Also, the evolution of the net current is found to follow the evolution of magnetic shear at the polarity inversion line.

  4. Modelling the flaring activity of the high-z, hard X-ray-selected blazar IGR J22517+2217: Flaring activity of IGR J22517+2217

    Lanzuisi, G.; De Rosa, A.; Ghisellini, G.; Panessa, F.

    2012-01-01

    We present new Suzaku and Fermi data and re-analysed archival hard X-ray data from the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) and Swift–Burst Alert Telescope (BAT) surveys to investigate the physical properties of the luminous, high-redshift, hard X-ray-selected blazar IGR J22517+2217, through the modelling of its broad-band spectral energy distribution (SED) in two different activity states. Through analysis of new Suzaku data and flux-selected data from archival hard X-ray observations, we build the source SED in two different states, one for the newly discovered flare that occurred in 2005 and one for the following quiescent period. Both SEDs are strongly dominated by the high-energy hump peaked at 10 20 –10 22 Hz, which is at least two orders of magnitude higher than the low-energy (synchrotron) one at 10 11 –10 14 Hz and varies by a factor of 10 between the two states. In both states the high-energy hump is modelled as inverse Compton emission between relativistic electrons and seed photons produced externally to the jet, while the synchrotron self-Compton component is found to be negligible. In our model the observed variability can be accounted for by a variation of the total number of emitting electrons and by a dissipation region radius changing from inside to outside the broad-line region as the luminosity increases. In its flaring activity, IGR J22517+2217 is revealed as one of the most powerful jets among the population of extreme, hard X-ray-selected, high-redshift blazars observed so far.

  5. Multiple-wavelength analysis of energy release during a solar flare - Thermal and nonthermal electron populations

    Willson, Robert F.; Lang, Kenneth R.; Klein, Karl-Ludwig; Kerdraon, Alain; Trottet, Gerard

    1990-01-01

    Collaborative solar investigations by Tufts University and the Observatoire de Paris have resulted in simultaneous radio observations with the Very Large Array (VLA) and the Nancay Radioheliograph (NR), comparisons of this radio data with X-ray observations, and theoretical interpretations of the dominant radiation mechanisms during a weak impulsive solar flare observed on May 28, 1988. The VLA has mapped the flaring structures at time intervals of 3.3 s, showing that the preflash and flash-phase components of the impulsive emission originate in spatially separated sources. The 20.7 cm preflash source is ascribed to thermal gyroresonance emission from coronal loops with typical magnetic field strengths of up to 270 G; this emission is associated with heating and exhibits no detectable hard X-ray radiation above 30 keV. The flash-phase 20.7 cm source and the hard X-ray emission are attributed to nonthermal electrons in the coronal and chromospheric portions of a magnetic loop. The combination of imaging observations at 20.7 and 91.6 cm excludes emission from a confined hot plasma during the flash phase.

  6. Magnetic structure of an activated filament in a flaring active region

    Sasso, C.; Lagg, A.; Solanki, S. K.

    2014-01-01

    Aims: While the magnetic field in quiescent prominences has been widely investigated, less is known about the field in activated prominences. We report observational results on the magnetic field structure of an activated filament in a flaring active region. In particular, we studied its magnetic structure and line-of-sight flows during its early activated phase, shortly before it displayed signs of rotation. Methods: We inverted the Stokes profiles of the chromospheric He i 10 830 Å triplet and the photospheric Si i 10 827 Å line observed in this filament by the Vacuum Tower Telescope on Tenerife. Using these inversion results, we present and interpret the first maps of the velocity and magnetic field obtained in an activated filament, both in the photosphere and the chromosphere. Results: Up to five different magnetic components are found in the chromospheric layers of the filament, while outside the filament a single component is sufficient to reproduce the observations. Magnetic components displaying an upflow are preferentially located towards the centre of the filament, while the downflows are concentrated along its periphery. Moreover, the upflowing gas is associated with an opposite-polarity magnetic configuration with respect to the photosphere, while the downflowing gas is associated with a same-polarity configuration. Conclusions: The activated filament has a very complex structure. Nonetheless, it is compatible with a flux rope, albeit a distorted one, in the normal configuration. The observations are best explained by a rising flux rope in which part of the filament material is still stably stored (upflowing material, rising with the field), while the rest is no longer stably stored and flows down along the field lines. The movie is available in electronic form at http://www.aanda.org

  7. Fibromyalgia Flares: A Qualitative Analysis.

    Vincent, Ann; Whipple, Mary O; Rhudy, Lori M

    2016-03-01

    Patients with fibromyalgia report periods of symptom exacerbation, colloquially referred to as "flares" and despite clinical observation of flares, no research has purposefully evaluated the presence and characteristics of flares in fibromyalgia. The purpose of this qualitative study was to describe fibromyalgia flares in a sample of patients with fibromyalgia. Using seven open-ended questions, patients were asked to describe how they perceived fibromyalgia flares and triggers and alleviating factors associated with flares. Patients were also asked to describe how a flare differs from their typical fibromyalgia symptoms and how they cope with fibromyalgia flares. Content analysis was used to analyze the text. A total of 44 participants completed the survey. Responses to the seven open-ended questions revealed three main content areas: causes of flares, flare symptoms, and dealing with a flare. Participants identified stress, overdoing it, poor sleep, and weather changes as primary causes of flares. Symptoms characteristic of flares included flu-like body aches/exhaustion, pain, fatigue, and variety of other symptoms. Participants reported using medical treatments, rest, activity and stress avoidance, and waiting it out to cope with flares. Our results demonstrate that periods of symptom exacerbation (i.e., flares) are commonly experienced by patients with fibromyalgia and symptoms of flares can be differentiated from every day or typical symptoms of fibromyalgia. Our study is the first of its kind to qualitatively explore characteristics, causes, and management strategies of fibromyalgia flares. Future studies are needed to quantitatively characterize fibromyalgia flares and evaluate mechanisms of flares. © 2015 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Defining active progressive multiple sclerosis

    Sellebjerg, Finn; Börnsen, Lars; Ammitzbøll, Cecilie

    2017-01-01

    BACKGROUND: It is unknown whether disease activity according to consensus criteria (magnetic resonance imaging activity or clinical relapses) associate with cerebrospinal fluid (CSF) changes in progressive multiple sclerosis (MS). OBJECTIVE: To compare CSF biomarkers in active and inactive...

  9. Solar neighbourhood flare stars - a review

    Kunkel, W.E.

    1975-01-01

    The review concentrates on 'astronomical' aspects of flare activity, such as where, and under what circumstances flare activity is found in the solar vicinity. Non-classical activity is briefly described (without regard for completeness) and the influence of detection effects on flare observations is treated. Flare stars discovered during the last four years are described and flare activity of local dMe stars is compared. The BY Draconis syndrome is discussed followed by some remarks about rotation. Pleiades flare activity is compared to that of the solar neighbourhood and evidence for the evolution of flare activity in stars is examined. (Auth.)

  10. Can we explain atypical solar flares?

    Dalmasse, K.; Chandra, R.; Schmieder, B.; Aulanier, G.

    2015-02-01

    Context. We used multiwavelength high-resolution data from ARIES, THEMIS, and SDO instruments to analyze a non-standard, C3.3 class flare produced within the active region NOAA 11589 on 2012 October 16. Magnetic flux emergence and cancellation were continuously detected within the active region, the latter leading to the formation of two filaments. Aims: Our aim is to identify the origins of the flare taking the complex dynamics of its close surroundings into account. Methods: We analyzed the magnetic topology of the active region using a linear force-free field extrapolation to derive its 3D magnetic configuration and the location of quasi-separatrix layers (QSLs), which are preferred sites for flaring activity. Because the active region's magnetic field was nonlinear force-free, we completed a parametric study using different linear force-free field extrapolations to demonstrate the robustness of the derived QSLs. Results: The topological analysis shows that the active region presented a complex magnetic configuration comprising several QSLs. The considered data set suggests that an emerging flux episode played a key role in triggering the flare. The emerging flux probably activated the complex system of QSLs, leading to multiple coronal magnetic reconnections within the QSLs. This scenario accounts for the observed signatures: the two extended flare ribbons developed at locations matched by the photospheric footprints of the QSLs and were accompanied with flare loops that formed above the two filaments, which played no important role in the flare dynamics. Conclusions: This is a typical example of a complex flare that can a priori show standard flare signatures that are nevertheless impossible to interpret with any standard model of eruptive or confined flare. We find that a topological analysis, however, permitted us to unveil the development of such complex sets of flare signatures. Movies associated to Figs. 1, 3, and 9 are only available at the CDS via

  11. MAGNETIC NON-POTENTIALITY OF SOLAR ACTIVE REGIONS AND PEAK X-RAY FLUX OF THE ASSOCIATED FLARES

    Tiwari, Sanjiv Kumar; Venkatakrishnan, P.; Gosain, Sanjay

    2010-01-01

    Predicting the severity of solar eruptive phenomena such as flares and coronal mass ejections remains a great challenge despite concerted efforts to do so over the past several decades. However, the advent of high-quality vector magnetograms obtained from Hinode (SOT/SP) has increased the possibility of meeting this challenge. In particular, the spatially averaged signed shear angle (SASSA) seems to be a unique parameter for quantifying the non-potentiality of active regions. We demonstrate the usefulness of the SASSA for predicting flare severity. For this purpose, we present case studies of the evolution of magnetic non-potentiality using 115 vector magnetograms of four active regions, namely, ARs NOAA 10930, 10960, 10961, and 10963 during 2006 December 8-15, 2007 June 3-10, 2007 June 28-July 5, and 2007 July 10-17, respectively. The NOAA ARs 10930 and 10960 were very active and produced X and M class flares, respectively, along with many smaller X-ray flares. On the other hand, the NOAA ARs 10961 and 10963 were relatively less active and produced only very small (mostly A- and B-class) flares. For this study, we have used a large number of high-resolution vector magnetograms obtained from Hinode (SOT/SP). Our analysis shows that the peak X-ray flux of the most intense solar flare emanating from the active regions depends on the magnitude of the SASSA at the time of the flare. This finding of the existence of a lower limit of the SASSA for a given class of X-ray flares will be very useful for space weather forecasting. We have also studied another non-potentiality parameter called the mean weighted shear angle (MWSA) of the vector magnetograms along with the SASSA. We find that the MWSA does not show such distinction as the SASSA for upper limits of the GOES X-ray flux of solar flares; however, both the quantities show similar trends during the evolution of all active regions studied.

  12. Solar flares

    Zirin, H.

    1974-01-01

    A review of the knowledge about solar flares which has been obtained through observations from the earth and from space by various methods is presented. High-resolution cinematography is best carried out at H-alpha wavelengths to reveal the structure, time history, and location of flares. The classification flares in H alpha according to either physical or morphological criteria is discussed. The study of flare morphology, which shows where, when, and how flares occur, is important for evaluating theories of flares. Consideration is given to studies of flares by optical spectroscopy, radio emissions, and at X-ray and XUV wavelengths. Research has shown where and possibly why flares occur, but the physics of the instability involved, of the particle acceleration, and of the heating are still not understood. (IAA)

  13. Analysis of peculiar penumbral flows observed in the active region NOAA 10930 during a major solar flare

    Kumar, Brajesh; Venkatakrishnan, P; Tiwari, Sanjiv Kumar; Mathur, Savita; Garcia, R A

    2011-01-01

    It is believed that the high energetic particles and tremendous amount of energy released during the flares can induce velocity oscillations in the Sun. Using the Dopplergrams obtained by Global Oscillation Network Group (GONG) telescope, we analyze the velocity flows in the active region NOAA 10930 during a major flare (of class X3.4) that occurred on 13 December 2006. We observe peculiar evolution of velocity flows in some localized portions of the penumbra of this active region during the flare. Application of Wavelet transform to these velocity flows reveals that there is major enhancement of velocity oscillations in the high-frequency regime (5-8 mHz), while there is feeble enhancement in the p mode oscillations (2-5 mHz) in the aforementioned location. It has been recently shown that flares can induce high-frequency global oscillations in the Sun. Therefore, it appears that during the flare process there might be a common origin for the excitation of local and global high-frequency oscillations in the Sun.

  14. The impact of patients reported flares on functional impairment in rheumatoid arthritis patients with low-disease activity

    Küttel, Dorota Paulina; Christensen, R.; Primdahl, J.

    2015-01-01

    -term outcomes. Objectives: To investigate whether transient patient reported flares can influence functional disability in patients with established low active RA. Methods: Out of 287 patients from the AMBRA trial (1), 268 RA patients with low disease activity (DAS28CRP MCID of 0.22) was compared across three...

  15. Applying the Weighted Horizontal Magnetic Gradient Method to a Simulated Flaring Active Region

    Korsós, M. B.; Chatterjee, P.; Erdélyi, R.

    2018-04-01

    Here, we test the weighted horizontal magnetic gradient (WG M ) as a flare precursor, introduced by Korsós et al., by applying it to a magnetohydrodynamic (MHD) simulation of solar-like flares. The preflare evolution of the WG M and the behavior of the distance parameter between the area-weighted barycenters of opposite-polarity sunspots at various heights is investigated in the simulated δ-type sunspot. Four flares emanated from this sunspot. We found the optimum heights above the photosphere where the flare precursors of the WG M method are identifiable prior to each flare. These optimum heights agree reasonably well with the heights of the occurrence of flares identified from the analysis of their thermal and ohmic heating signatures in the simulation. We also estimated the expected time of the flare onsets from the duration of the approaching–receding motion of the barycenters of opposite polarities before each single flare. The estimated onset time and the actual time of occurrence of each flare are in good agreement at the corresponding optimum heights. This numerical experiment further supports the use of flare precursors based on the WG M method.

  16. Flare colours and luminosities

    Cristaldi, S.; Rodono, M.

    1975-01-01

    Flare colours determined from simultaneous UBV observations made at Catania Observatory and from sequential UBV observations made at McDonald Observatory are presented. They fit fairly well with the theoretical colours computed according to the Gurzadian's (1970) non-thermal model. Only part of the observed flare colours are consistent with the solar type models by Gershberg (1967) and Kunkel (1970). From a B-band patrol of UV Cet-type stars carried out from 1967 to 1972, some quantitative estimates of flare frequencies and luminosities and their average contributions to the stellar radiation are given. The corresponding parameters for the Sun, which were estimated from 'white light' flare activity, are also given for comparison. The Sun and V 1216 Sgr can be regarded as low-activity flare stars of the type found by Kunkel (1973). (Auth.)

  17. ON THE FLARE-INDUCED SEISMICITY IN THE ACTIVE REGION NOAA 10930 AND RELATED ENHANCEMENT OF GLOBAL WAVES IN THE SUN

    Kumar, Brajesh; Venkatakrishnan, P.; Mathur, Savita; Tiwari, Sanjiv Kumar; García, R. A.

    2011-01-01

    A major flare (of class X3.4) occurred on 2006 December 13 in the active region NOAA 10930. This flare event has remained interesting to solar researchers for studies related to particle acceleration during the flare process and the reconfiguration of magnetic fields as well as fine-scale features in the active region. The energy released during flares is also known to induce acoustic oscillations in the Sun. Here, we analyze the line-of-sight velocity patterns in this active region during the X3.4 flare using the Dopplergrams obtained by the Global Oscillation Network Group (GONG) instrument. We have also analyzed the disk-integrated velocity observations of the Sun obtained by the Global Oscillation at Low Frequency (GOLF) instrument on board the Solar and Heliospheric Observatory spacecraft as well as full-disk collapsed velocity signals from GONG observations during this flare to study any possible connection between the flare-related changes seen in the local and global velocity oscillations in the Sun. We apply wavelet transform to the time series of the localized velocity oscillations as well as the global velocity oscillations in the Sun spanning the flare event. The line-of-sight velocity shows significant enhancement in some localized regions of the penumbra of this active region during the flare. The affected region is seen to be away from the locations of the flare ribbons and the hard X-ray footpoints. The sudden enhancement of this velocity seems to be caused by the Lorentz force driven by the 'magnetic jerk' in the localized penumbral region. Application of wavelet analysis to these flare-induced localized seismic signals shows significant enhancement in the high-frequency domain (5 <ν < 8 mHz) and a feeble enhancement in the p-mode oscillations (2 <ν < 5 mHz) during the flare. On the other hand, the wavelet analysis of GOLF velocity data and the full-disk collapsed GONG velocity data spanning the flare event indicates significant post-flare

  18. A Comparative Study of the Eruptive and Non-eruptive Flares Produced by the Largest Active Region of Solar Cycle 24

    Sarkar, Ranadeep; Srivastava, Nandita

    2018-02-01

    We investigate the morphological and magnetic characteristics of solar active region (AR) NOAA 12192. AR 12192 was the largest region of Solar Cycle 24; it underwent noticeable growth and produced 6 X-class flares, 22 M-class flares, and 53 C-class flares in the course of its disc passage. However, the most peculiar fact of this AR is that it was associated with only one CME in spite of producing several X-class flares. In this work, we carry out a comparative study between the eruptive and non-eruptive flares produced by AR 12192. We find that the magnitude of abrupt and permanent changes in the horizontal magnetic field and Lorentz force are significantly smaller in the case of the confined flares compared to the eruptive one. We present the areal evolution of AR 12192 during its disc passage. We find the flare-related morphological changes to be weaker during the confined flares, whereas the eruptive flare exhibits a rapid and permanent disappearance of penumbral area away from the magnetic neutral line after the flare. Furthermore, from the extrapolated non-linear force-free magnetic field, we examine the overlying coronal magnetic environment over the eruptive and non-eruptive zones of the AR. We find that the critical decay index for the onset of torus instability was achieved at a lower height over the eruptive flaring region, than for the non-eruptive core area. These results suggest that the decay rate of the gradient of overlying magnetic-field strength may play a decisive role to determine the CME productivity of the AR. In addition, the magnitude of changes in the flare-related magnetic characteristics are found to be well correlated with the nature of solar eruptions.

  19. Short-term evolution and coexistence of spots, plages and flare activity on LQ Hydrae

    Flores Soriano, M.; Strassmeier, K. G.

    2017-01-01

    Aims: We aim to study the short-term evolution of the chromospheric and photospheric activity of the young, single K2 dwarf LQ Hya. Methods: Four months of quasi-simultaneous spectroscopic and photometric observations were used to study the variations of the photometric light curve, the evolution of the chromospheric activity from the Hα and Hβ lines, and the distribution of cool spots from Doppler maps. Results: During our observations one side of the star was more active than the other. The equivalent width of the Hα line from the least active hemisphere increased from ≈0.7 Å at the beginning of the observation to 1.0 Å at the end. The basal emission of the most active hemisphere remained roughly constant at EWHαt1.0 Å. Intense flare activity was observed during the first twenty days, where at least four different events were detected. The line asymmetries of the Hα line suggest that one of the flares could have produced a mass ejection with a maximum projected speed of 70kms-1. The rotational modulation of the V-band photometry showed clear anti-correlation with the chromospheric activity. The difference in brightness between the opposite hemispheres decreased from 0.m16 to 0.m09 in two months. Three spots gradually moving apart from each other are dominating the photospheric Doppler maps. The comparison between the maps and the Hα line as the star rotates reveals the spatial coexistence of chromospheric Hα emission and photospheric spots. Conclusions: Our results indicate that the active regions of LQ Hya can live for at least four months. The detected changes in the photometric light curve and the spectroscopic Doppler images seem to be more a consequence of the spatial redistribution of the active regions rather than due to changes in their strength. Only one of the active regions shows significant changes in its chromospheric emission. Based on data obtained with the STELLA robotic telescope in Tenerife, an AIP facility jointly operated by AIP

  20. The flare in alkaline phosphatase activity post-orchidectomy predicts which patient may benefit from early chemotherapy in metastatic prostate cancer

    Pelger, Rob C. M.; Lycklama A Nijeholt, Guus A. B.; Zwinderman, Aielko H.; Hamdy, Neveen A. T.

    2002-01-01

    BACKGROUND: A flare in serum alkaline phosphatase (ALP) activity post-orchidectomy has been shown to be of negative prognostic value for progression-free survival (PFS) in patients with prostate cancer. The aim of this study was to investigate whether a flare in ALP may help identify patients in

  1. Flare stars

    Nicastro, A.J.

    1981-01-01

    The least massive, but possibly most numerous, stars in a galaxy are the dwarf M stars. It has been observed that some of these dwarfs are characterized by a short increase in brightness. These stars are called flare stars. These flare stars release a lot of energy in a short amount of time. The process producing the eruption must be energetic. The increase in light intensity can be explained by a small area rising to a much higher temperature. Solar flares are looked at to help understand the phenomenon of stellar flares. Dwarfs that flare are observed to have strong magnetic fields. Those dwarf without the strong magnetic field do not seem to flare. It is believed that these regions of strong magnetic fields are associated with star spots. Theories on the energy that power the flares are given. Astrophysicists theorize that the driving force of a stellar flare is the detachment and collapse of a loop of magnetic flux. The mass loss due to stellar flares is discussed. It is believed that stellar flares are a significant contributor to the mass of interstellar medium in the Milky Way

  2. Recent big flare

    Moriyama, Fumio; Miyazawa, Masahide; Yamaguchi, Yoshisuke

    1978-01-01

    The features of three big solar flares observed at Tokyo Observatory are described in this paper. The active region, McMath 14943, caused a big flare on September 16, 1977. The flare appeared on both sides of a long dark line which runs along the boundary of the magnetic field. Two-ribbon structure was seen. The electron density of the flare observed at Norikura Corona Observatory was 3 x 10 12 /cc. Several arc lines which connect both bright regions of different magnetic polarity were seen in H-α monochrome image. The active region, McMath 15056, caused a big flare on December 10, 1977. At the beginning, several bright spots were observed in the region between two main solar spots. Then, the area and the brightness increased, and the bright spots became two ribbon-shaped bands. A solar flare was observed on April 8, 1978. At first, several bright spots were seen around the solar spot in the active region, McMath 15221. Then, these bright spots developed to a large bright region. On both sides of a dark line along the magnetic neutral line, bright regions were generated. These developed to a two-ribbon flare. The time required for growth was more than one hour. A bright arc which connects two ribbons was seen, and this arc may be a loop prominence system. (Kato, T.)

  3. X-RAY FLARING ACTIVITY OF MRK 421 IN THE FIRST HALF OF 2013

    Kapanadze, B.; Kapanadze, S.; Tabagari, L. [E. Kharadze Abastumani Astrophysical Observatory, Ilia State University, Colokashvili Av. 3/5, Tbilisi, 0162, Georgia (United States); Dorner, D. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics, Emil-Fischer-Str. 31, D-97074 Würtzburg (Germany); Vercellone, S.; Romano, P. [INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy); Aller, H.; Aller, M.; Hughes, P.; Reynolds, M. [Astronomy Department, University of Michigan, Ann Arbor, MI 48109-1107 (United States)

    2016-11-01

    We present the results of the Swift and NuSTAR observations of the nearby BL Lac object Mrk 421 during 2013 January–June. The source exhibited a strong long-term variability in the 0.3–10 keV and 3–79 keV bands with the maximum-to-minimum daily-binned flux ratios of 22 and 95, respectively, in about 3 months, mainly due to unprecedented strong X-ray outbursts by more than an order of magnitude in both bands within 2 weeks in 2013 April when the 0.3–10 keV count rate exceeded the level of 200 cts s{sup −1} for the first time, and Mrk 421 became one of the brightest sources in the X-ray sky. The source was also very active on intra-day timescales, and it showed flux doubling and halving timescales of 1.16–7.20 hr and 1.04–3.54 hr, respectively. On some occasions, the flux varied by 4%–23% within 300–840 s. During this period, the source also exhibited some of the most extreme X-ray spectral variability ever reported for BL Lacs—the location of the synchrotron spectral energy distribution peak shifted from a few eV to ∼10 keV, and the photon index at 1 keV and curvature parameter varied on timescales from a few weeks down to intervals shorter than 1 ks. MAGIC and First G-APD Cherenkov Telescope observations also revealed a very strong very high energy (VHE) flare during April 11–17. The UV and HE γ -ray flares were much weaker compared to their X-ray counterparts, and they generally showed significantly stronger correlation with each other than with the X-ray fluxes.

  4. State Transition and Flaring Activity of IGR J17464-3213/H1743-322 with INTEGRAL SPI

    Joinet, A.; Jourdain, E.; Malzac, J.; Roques, J. P.; Schönfelder, V.; Ubertini, P.; Capitanio, F.

    2005-08-01

    IGR J17464-3213, already known as the HEAO 1 transient source H1743-322, has been detected during a state transition by INTEGRAL SPI. We describe the spectral evolution and flaring activity of IGR J17464-3213/H1743-322 from 2003 March 21 to 2003 April 22. During the first part, the source followed a continuous spectral softening, with the peak of the spectral energy distribution shifting from 100 keV down to ~a few keV. However, the thermal disk and the hard X-ray components had a similar intensity, indicating that the source was in an intermediate state throughout our observations and evolving toward the soft state. In the second part of our observations, the RXTE ASM and INTEGRAL SPI light curves showed a strong flaring activity. Two flare events lasting about 1 day each have been detected with SPI and are probably due to instabilities in the accretion disk associated with the state transition. During these flares, the low (1.5-12 keV) and high (20-200 keV) energy fluxes monitored with the RXTE ASM and INTEGRAL SPI are correlated, and the spectral shape (above 20 keV) remains unchanged while the luminosity increases by a factor greater than 2.

  5. Sun and solar flares

    McKenna-Lawlor, S. (Saint Patrick' s Coll., Maynooth (Ireland))

    1982-07-01

    The subject is discussed under the headings: the sun's core (thermonuclear reactions, energy transfer from core through radiation zone, convection zone, photosphere, chromosphere and corona); the photosphere (convection, granulation, sunspots, magnetic fields, solar cycle, rotation of the sun); solar variability and paleoclimatic records (correlation of low solar activity with increased /sup 14/C production in atmosphere); the chromosphere and corona (turbulence, temperature, coronal streamers, energy transfer); solar flares (cosmic rays, aurorae, spectra, velocity of flares, prominences, mechanisms of flares); the solar wind.

  6. Detailed analysis of dynamic evolution of three Active Regions at the photospheric level before flare and CME occurrence

    Ye, Yudong; Korsós, M. B.; Erdélyi, R.

    2018-01-01

    We present a combined analysis of the applications of the weighted horizontal magnetic gradient (denoted as WGM in Korsós et al. (2015)) method and the magnetic helicity tool (Berger and Field, 1984) employed for three active regions (ARs), namely NOAA AR 11261, AR 11283 and AR 11429. We analysed the time series of photospheric data from the Solar Dynamics Observatory taken between August 2011 and March 2012. During this period the three ARs produced a series of flares (eight M- and six X-class) and coronal mass ejections (CMEs). AR 11261 had four M-class flares and one of them was accompanied by a fast CME. AR 11283 had similar activities with two M- and two X-class flares, but only with a slow CME. Finally, AR 11429 was the most powerful of the three ARs as it hosted five compact and large solar flare and CME eruptions. For applying the WGM method we employed the Debrecen sunspot data catalogue, and, for estimating the magnetic helicity at photospheric level we used the Space-weather HMI Active Region Patches (SHARP's) vector magnetograms from SDO/HMI (Solar Dynamics Observatory/Helioseismic and Magnetic Imager). We followed the evolution of the components of the WGM and the magnetic helicity before the flare and CME occurrences. We found a unique and mutually shared behaviour, called the U-shaped pattern, of the weighted distance component of WGM and of the shearing component of the helicity flux before the flare and CME eruptions. This common pattern is associated with the decreasing-receding phases yet reported only known to be a necessary feature prior to solar flare eruption(s) but found now at the same time in the evolution of the shearing helicity flux. This result leads to the conclusions that (i) the shearing motion of photospheric magnetic field may be a key driver for solar eruption in addition to the flux emerging process, and that (ii) the found decreasing-approaching pattern in the evolution of shearing helicity flux may be another precursor

  7. Observations of white-light flares in NOAA active region 11515: high occurrence rate and relationship with magnetic transients

    Song, Y. L.; Tian, H.; Zhang, M.; Ding, M. D.

    2018-06-01

    Aims: There are two goals in this study. One is to investigate how frequently white-light flares (WLFs) occur in a flare-productive active region (NOAA active region 11515). The other is to investigate the relationship between WLFs and magnetic transients (MTs). Methods: We used the high-cadence (45 s) full-disk continuum filtergrams and line-of-sight magnetograms taken by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) to identify WLFs and MTs, respectively. Images taken by the Atmospheric Imaging Assembly (AIA) on board SDO were also used to show the flare morphology in the upper atmosphere. Results: We found at least 20 WLFs out of a total of 70 flares above C class (28.6%) in NOAA active region 11515 during its passage across the solar disk (E45°-W45°). Each of these WLFs occurred in a small region, with a short duration of about 5 min. The enhancement of the white-light continuum intensity is usually small, with an average enhancement of 8.1%. The 20 WLFs we observed were found along an unusual configuration of the magnetic field that was characterized by a narrow ribbon of negative field. Furthermore, the WLFs were found to be accompanied by MTs, with radical changes in magnetic field strength (or even a sign reversal) observed during the flare. In contrast, there is no obvious signature of MTs in the 50 flares without white-light enhancements. Conclusions: Our results suggest that WLFs occur much more frequently than previously thought, with most WLFs being fairly weak enhancements. This may explain why WLFs are reported rarely. Our observations also suggest that MTs and WLFs are closely related and appear cospatial and cotemporal, when considering HMI data. A greater enhancement of WL emission is often accompanied by a greater change in the line-of-sight component of the unsigned magnetic field. Considering the close relationship between MTs and WLFs, many previously reported flares with MTs may be WLFs. The movie

  8. Which of Kepler's Stars Flare?

    Kohler, Susanna

    2017-12-01

    The habitability of distant exoplanets is dependent upon many factors one of which is the activity of their host stars. To learn about which stars are most likely to flare, a recent study examines tens of thousands of stellar flares observed by Kepler.Need for a Broader SampleArtists rendering of a flaring dwarf star. [NASAs Goddard Space Flight Center/S. Wiessinger]Most of our understanding of what causes a star to flare is based on observations of the only star near enough to examine in detail the Sun. But in learning from a sample size of one, a challenge arises: we must determine which conclusions are unique to the Sun (or Sun-like stars), and which apply to other stellar types as well.Based on observations and modeling, astronomers think that stellar flares result from the reconnection of magnetic field lines in a stars outer atmosphere, the corona. The magnetic activity is thought to be driven by a dynamo caused by motions in the stars convective zone.HR diagram of the Kepler stars, with flaring main-sequence (yellow), giant (red) and A-star (green) stars in the authors sample indicated. [Van Doorsselaere et al. 2017]To test whether these ideas are true generally, we need to understand what types of stars exhibit flares, and what stellar properties correlate with flaring activity. A team of scientists led by Tom Van Doorsselaere (KU Leuven, Belgium) has now used an enormous sample of flares observed by Kepler to explore these statistics.Intriguing TrendsVan Doorsselaere and collaborators used a new automated flare detection and characterization algorithm to search through the raw light curves from Quarter 15 of the Kepler mission, building a sample of 16,850 flares on 6,662 stars. They then used these to study the dependence of the flare occurrence rate, duration, energy, and amplitude on the stellar spectral type and rotation period.This large statistical study led the authors to several interesting conclusions, including:Flare star incidence rate as a a

  9. The origin of two X-class flares in active region NOAA 12673. Shear flows and head-on collision of new and preexisting flux

    Verma, Meetu

    2018-05-01

    Flare-prolific active region NOAA 12673 produced consecutive X2.2 and X9.3 flares on the 6 September 2017. To scrutinize the morphological, magnetic, and horizontal flow properties associated with these flares, a seven-hour time series was used consisting of continuum images, line-of-sight and vector magnetograms, and 1600 Å UV images. These data were acquired with the Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA). The white-light flare emission differed for both flares, while the X2.2 flare displayed localized, confined flare kernels, the X9.3 flare exhibited a two-ribbon structure. In contrast, the excess UV emission exhibited a similar structure for both flares, but with larger areal extent for the X9.3 flare. These two flares represented a scenario in which the first confined flare acted as precursor, setting up the stage for the more extended flare. Difference maps for continuum and magnetograms revealed locations of significant changes, that is, penumbral decay and umbral strengthening. The curved magnetic polarity inversion line in the δ-spot was the fulcrum of most changes. Horizontal proper motions were computed using the differential affine velocity estimator for vector magnetograms (DAVE4VM). Persistent flow features included (1) strong shear flows along the polarity inversion line, where the negative, parasitic polarity tried to bypass the majority, positive-polarity part of the δ-spot in the north, (2) a group of positive-polarity spots, which moved around the δ-spot in the south, moving away from the δ-spot with significant horizontal flow speeds, and (3) intense moat flows partially surrounding the penumbra of several sunspots, which became weaker in regions with penumbral decay. The enhanced flare activity has its origin in the head-on collision of newly emerging flux with an already existing regular, α-spot. Umbral cores of emerging bipoles were incorporated in its penumbra, creating a δ-configuration with

  10. Flare energetics

    Wu, S. T.; Dejager, C.; Dennis, B. R.; Hudson, H. S.; Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner, M. E.; Cargill, P. J.

    1986-01-01

    In this investigation of flare energetics, researchers sought to establish a comprehensive and self-consistent picture of the sources and transport of energy within a flare. To achieve this goal, they chose five flares in 1980 that were well observed with instruments on the Solar Maximum Mission, and with other space-borne and ground-based instruments. The events were chosen to represent various types of flares. Details of the observations available for them and the corresponding physical parameters derived from these data are presented. The flares were studied from two perspectives, the impulsive and gradual phases, and then the results were compared to obtain the overall picture of the energics of these flares. The role that modeling can play in estimating the total energy of a flare when the observationally determined parameters are used as the input to a numerical model is discussed. Finally, a critique of the current understanding of flare energetics and the methods used to determine various energetics terms is outlined, and possible future directions of research in this area are suggested.

  11. TEMPORAL EVOLUTION OF CHROMOSPHERIC OSCILLATIONS IN FLARING REGIONS: A PILOT STUDY

    Monsue, T.; Stassun, K. G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Hill, F., E-mail: teresa.monsue@vanderbilt.edu, E-mail: keivan.stassun@vanderbilt.edu, E-mail: hill@email.noao.edu [National Solar Observatory, Tucson, AZ 85719 (United States)

    2016-10-01

    We have analyzed H α intensity images obtained at a 1 minute cadence with the Global Oscillation Network Group (GONG) system to investigate the properties of oscillations in the 0–8 mHz frequency band at the location and time of strong M- and X-class flares. For each of three subregions within two flaring active regions, we extracted time series from multiple distinct positions, including the flare core and quieter surrounding areas. The time series were analyzed with a moving power-map analysis to examine power as a function of frequency and time. We find that, in the flare core of all three subregions, 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 flare cores. 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. Dark lanes of reduced wave power are also visible in the power maps, which may arise from the interaction of the acoustic waves and the magnetic field.

  12. Features of Microwave Radiation and Magnetographic Characteristics of Solar Active Region NOAA 12242 Before the X1.8 Flare on December 20, 2014

    Abramov-Maximov, V. E.; Borovik, V. N.; Opeikina, L. V.; Tlatov, A. G.; Yasnov, L. V.

    2017-12-01

    This paper continues the cycle of authors' works on the detection of precursors of large flares (M5 and higher classes) in active regions (ARs) of the Sun by their microwave radiation and magnetographic characteristics. Generalization of the detected precursors of strong flares can be used to develop methods for their prediction. This paper presents an analysis of the development of NOAA AR 12242, in which an X1.8 flare occurred on December 20, 2014. The analysis is based on regular multiazimuth and multiwavelength observations with the RATAN-600 radio telescope in the range 1.65-10 cm with intensity and circular polarization analysis and data from the Solar Dynamics Observatory (SDO). It was found that a new component appeared in the AR microwave radiation two days before the X-flare. It became dominant in the AR the day before the flare and significantly decreased after the flare. The use of multiazimuth observations from RATAN-600 and observations at 1.76 cm from the Nobeyama Radioheliograph made it possible to identify the radio source that appeared before the X-flare with the site of the closest convergence of opposite polarity fields near the neutral line in the AR. It was established that the X-flare occurred 20 h after the total gradient of the magnetic field of the entire region calculated from SDO/HMI data reached its maximum value. Analysis of the evolution of the microwave source that appeared before the X-flare in AR 12242 and comparison of its parameters with the parameters of other components of the AR microwave radiation showed that the new source can be classified as neutral line associated sources (NLSs), which were repeatedly detected by the RATAN-600 and other radio telescopes 1-3 days before the large flares.

  13. FARIMA MODELING OF SOLAR FLARE ACTIVITY FROM EMPIRICAL TIME SERIES OF SOFT X-RAY SOLAR EMISSION

    Stanislavsky, A. A.; Burnecki, K.; Magdziarz, M.; Weron, A.; Weron, K.

    2009-01-01

    A time series of soft X-ray emission observed by the Geostationary Operational Environment Satellites from 1974 to 2007 is analyzed. We show that in the solar-maximum periods the energy distribution of soft X-ray solar flares for C, M, and X classes is well described by a fractional autoregressive integrated moving average model with Pareto noise. The model incorporates two effects detected in our empirical studies. One effect is a long-term dependence (long-term memory), and another corresponds to heavy-tailed distributions. The parameters of the model: self-similarity exponent H, tail index α, and memory parameter d are statistically stable enough during the periods 1977-1981, 1988-1992, 1999-2003. However, when the solar activity tends to minimum, the parameters vary. We discuss the possible causes of this evolution and suggest a statistically justified model for predicting the solar flare activity.

  14. DETECTION OF HIGH-ENERGY GAMMA-RAY EMISSION DURING THE X-RAY FLARING ACTIVITY IN GRB 100728A

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Borgland, A. W.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bhat, P. N.; Bissaldi, E.; Bonamente, E.; Bonnell, J.; Bouvier, A.; Brigida, M.

    2011-01-01

    We present the simultaneous Swift and Fermi observations of the bright GRB 100728A and its afterglow. The early X-ray emission is dominated by a vigorous flaring activity continuing until 1 ks after the burst. In the same time interval, high-energy emission is significantly detected by the Fermi/Large Area Telescope. Marginal evidence of GeV emission is observed up to later times. We discuss the broadband properties of this burst within both the internal and external shock scenarios, with a particular emphasis on the relation between X-ray flares, the GeV emission, and a continued long-duration central engine activity as their power source.

  15. Does erythrocyte sedimentation rate reflect and discriminate flare from infection in systemic lupus erythematosus? Correlation with clinical and laboratory parameters of disease activity.

    Schäfer, Valentin Sebastian; Weiß, Katharina; Krause, Andreas; Schmidt, Wolfgang Andreas

    2018-07-01

    To examine disease activity parameters in patients with systemic lupus erythematosus (SLE) experiencing flare, infection, both, or neither condition, focusing on erythrocyte sedimentation rate (ESR). This study is a retrospective analysis of 371 consecutive inpatient SLE cases from 2006 to 2015. Cases were classified as flare (n = 147), infection (n = 48), both (n = 23), or neither (n = 135). ESR levels were correlated to C-reactive protein (CRP), ferritin, anti-dsDNA antibodies, complement C3 reduction, serositis, and erythrocyturia with proteinuria (Pearson's correlation). ESR levels were related to an age- and gender-adapted cut-off value (ESRp). We analyzed mean values of age, ESR, ESRp, CRP, ferritin and distribution of anti-dsDNA antibodies, C3 reduction, serositis, and erythrocyturia with proteinuria. Sensitivity and specificity were calculated via receiver operating characteristic or two-by-two table. Association of parameters with disease activity and infection was tested via two-sided chi square test. ESR correlated moderately with CRP in cases with flare and/or infection (r = 0.505-0.586). While ESR and CRP were normal in remission, mean values overlapped in cases with flare, infection, or both. ESRp was higher in flare than in infection (p = 0.048). ESR lost association to activity in infected cases, CRP to infection in flaring cases. ESRp, serositis, and anti-dsDNA antibodies were related to disease activity regardless of infections. Anti-dsDNA antibodies were most sensitive for detecting flares (74%), while serositis, proteinuria with erythrocyturia, anti-dsDNA antibodies, C3 reduction, and ESRp values ≥ 2 were most specific. ESR levels were raised by flares, infections, and age; adapting them to age and gender increased their diagnostic value. Obtaining several parameters remains necessary to differentiate flare from infection.

  16. Solar flares

    Kaastra, J.S.

    1985-01-01

    In this thesis an electrodynamic model for solar flares is developed. The main theoretical achievements underlying the present study are treated briefly and the observable flare parameters are described within the framework of the flare model of this thesis. The flare model predicts large induced electric fields. Therefore, acceleration processes of charged particles by direct electric fields are treated. The spectrum of the accelerated particles in strong electric fields is calculated, 3 with the electric field and the magnetic field perpendicular and in the vicinity of an X-type magnetic neutral line. An electromagnetic field configuration arises in the case of a solar flare. A rising current filament in a quiescent background bipolar magnetic field causes naturally an X-type magnetic field configuration below the filament with a strong induced electric field perpendicular to the ambient magnetic field. This field configuration drives particles and magnetic energy towards the neutral line, where a current sheet is generated. The global evolution of the fields in the flare is determined by force balance of the Lorentz forces on the filament and the force balance on the current sheet. The X-ray, optical and radio observations of a large solar flare on May 16, 1981 are analyzed. It is found that these data fit the model very well. (Auth.)

  17. Anthropogenic activities impact on atmospheric environmental quality in a gas-flaring community: application of fuzzy logic modelling concept.

    Akintola, Olayiwola Akin; Sangodoyin, Abimbola Yisau; Agunbiade, Foluso Oyedotun

    2018-05-24

    We present a modelling concept for evaluating the impacts of anthropogenic activities suspected to be from gas flaring on the quality of the atmosphere using domestic roof-harvested rainwater (DRHRW) as indicator. We analysed seven metals (Cu, Cd, Pb, Zn, Fe, Ca, and Mg) and six water quality parameters (acidity, PO 4 3- , SO 4 2- , NO 3 - , Cl - , and pH). These were used as input parameters in 12 sampling points from gas-flaring environments (Port Harcourt, Nigeria) using Ibadan as reference. We formulated the results of these input parameters into membership function fuzzy matrices based on four degrees of impact: extremely high, high, medium, and low, using regulatory limits as criteria. We generated indices that classified the degree of anthropogenic activity impact on the sites from the product membership function matrices and weight matrices, with investigated (gas-flaring) environment as between medium and high impact compared to those from reference (residential) environment that was classified as between low and medium impact. Major contaminants of concern found in the harvested rainwater were Pb and Cd. There is also the urgent need to stop gas-flaring activities in Port Harcourt area in particular and Niger Delta region of Nigeria in general, so as to minimise the untold health hazard that people living in the area are currently faced with. The fuzzy methodology presented has also indicated that the water cannot safely support potable uses and should not be consumed without purification due to the impact of anthropogenic activities in the area but may be useful for other domestic purposes.

  18. Using coronal loops to reconstruct the magnetic field of an active region before and after a major flare

    Malanushenko, A. [Department of Physics, Montana State University, Bozeman, MT (United States); Schrijver, C. J.; DeRosa, M. L. [Lockheed Martin Advanced Technology Center, Palo Alto, CA (United States); Wheatland, M. S. [Sydney Institute for Astronomy, School of Physics, University of Sydney, Redfern, NSW (Australia)

    2014-03-10

    The shapes of solar coronal loops are sensitive to the presence of electrical currents that are the carriers of the non-potential energy available for impulsive activity. We use this information in a new method for modeling the coronal magnetic field of active region (AR) 11158 as a nonlinear force-free field (NLFFF). The observations used are coronal images around the time of major flare activity on 2011 February 15, together with the surface line-of-sight magnetic field measurements. The data are from the Helioseismic and Magnetic Imager and Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. The model fields are constrained to approximate the coronal loop configurations as closely as possible, while also being subject to the force-free constraints. The method does not use transverse photospheric magnetic field components as input and is thereby distinct from methods for modeling NLFFFs based on photospheric vector magnetograms. We validate the method using observations of AR 11158 at a time well before major flaring and subsequently review the field evolution just prior to and following an X2.2 flare and associated eruption. The models indicate that the energy released during the instability is about 1 × 10{sup 32} erg, consistent with what is needed to power such a large eruptive flare. Immediately prior to the eruption, the model field contains a compact sigmoid bundle of twisted flux that is not present in the post-eruption models, which is consistent with the observations. The core of that model structure is twisted by ≈0.9 full turns about its axis.

  19. Probing quantum gravity using photons from a flare of the active galactic nucleus Markarian 501 observed by the MAGIC telescope

    Albert, J; Anderhub, H; Antonelli, L A; Antoranz, P; Backes, M; Baixeras, C; Barrio, J A; Bartko, H; Bastieri, D; Becker, J K; Bednarek, W; Berger, K; Bernardini, E; Bigongiari, C; Biland, A; Bock, R K; Bordas, P; Bosch-Ramon, V; Bretz, T; Britvitch, I; Camara, M; Carmona, E; Chilingarian, A; Commichau, S; Contreras, J L; Cortina, J; Costado, M T; Covino, S; Dazzi, F; De Angelis, A; De Cea del Pozo, E; Delgado Mendez, C; de los Reyes, R; De Lotto, B; De Maria, M; De Sabata, F; Dominguez, A; Dorner, D; Doro, M; Errando, M; Fagiolini, M; Ferenc, D; Fernández, E; Firpo, R; Fonseca, M V; Font, L; Galante, N; García-López, R J; Garczarczyk, M; Gaug, M; Göbel, F; Hayashida, M; Herrero, A; Höhne, D; Hose, J; Hsu, C C; Huber, S; Jogler, T; Kranich, D; La Barbera, A; Laille, A; Leonardo, E; Lindfors, E; Lombardi, S; Longo, F; López, M; Lorenz, E; Majumdar, P; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Mariotti, M; Martínez, M; Mazin, D; Meucci, M; Meyer, M; Miranda, J M; Mirzoyan, R; Moles, M; Moralejo, A; Nieto, D; Nilsson, K; Ninkovic, J; Otte, N; Oya, I; Panniello, M; Paoletti, R; Paredes, J M; Pasanen, M; Pascoli, D; Pauss, F; Pegna, R; Pérez-Torres, M A; Persic, M; Peruzzo, L; Piccioli, A; Prada, F; Puchades, N; Raymers, A; Ribó, M; Rico, J; Rissi, M; Robert, A; Rügamer, S; Saggion, A; Saitô, T; Salvati, M; Sanchez-Conde, M; Sartori, P; Satalecka, K; Scalzotto, V; Scapin, V; Schmitt, R; Schweizer, T; Shayduk, M; Shinozaki, K; Sidro, N; Sierpowska-Bartosik, A; Sillanpää, A; Spanier, F; Stamerra, A; Stark, L S; Takalo, L; Tavecchio, F; Temnikov, P; Tescaro, D; Teshima, M; Tluczykont, M; Torres, D F; Turini, N; Vankov, H; Venturini, A; Vitale, V; Wagner, R M; Wittek, W; Zabalza, M; Zandanel, F; Zanin, R; Ellis, Jonathan Richard; Mavromatos, N E; Nanopoulos, D V; Sakharov, Alexander S; Sarkisyan-Grinbaum, E

    2008-01-01

    We use the timing of photons observed by the MAGIC gamma-ray telescope during a flare of the active galaxy Markarian 501 to probe a vacuum refractive index ~ 1-(E/M_QGn)^n, n = 1,2, that might be induced by quantum gravity. The peaking of the flare is found to maximize for quantum-gravity mass scales M_QG1 ~ 0.4x10^18 GeV or M_QG2 ~ 0.6x10^11 GeV, and we establish lower limits M_QG1 > 0.26x10^18 GeV or M_QG2 > 0.39x10^11 GeV at the 95% C.L. Monte Carlo studies confirm the MAGIC sensitivity to propagation effects at these levels. Thermal plasma effects in the source are negligible, but we cannot exclude the importance of some other source effect.

  20. Search for neutrino events in the Kamiokande-II detector in correlation with the solar-flare activity in March 1989

    Hirata, K.S.; Kajita, T.; Kifune, T.

    1989-12-01

    A search has been made for neutrino events (E v > or approx. 50 MeV) in the Kamiokande-II water Cherenkov detector in correlation with the great solar-flare activity observed in March 1989. No evidence was obtained for such a correlation. Upper limits are separately given for the optical importance 4, 3, and 2 flares for both time-integrated and time-averaged solar-flare ν e fluxes at E v = 50 MeV and 100 MeV. At E v = 100 MeV, the 90% confidence-level upper limit for the time-integrated ν e flux per importance 4 (3) flare is 3.5 x 10 7 (1.4x10 7 ) cm -2 . Even the upper limit for the importance 4 flare is considerably lower than the ν e flux at the corresponding energy needed to explain the excess neutrino captures reported in some of the 37 Cl experimental runs when large solar flares occurred. A search has also been made for low-energy events (recoil e +- energy > or approx. 10 MeV) in correlation with importance ≥ 2 flares and with the solar proton flux ≥ 10 MeV). Again, no significant signal has been observed. (author)

  1. GAMMA-RAY ACTIVITY IN THE CRAB NEBULA: THE EXCEPTIONAL FLARE OF 2011 APRIL

    Buehler, R.; Blandford, R. D.; Charles, E.; Chiang, J.; Funk, S.; Kerr, M.; Massaro, F.; Romani, R. W.; Scargle, J. D.; Baldini, L.; Baring, M. G.; Belfiore, A.; Saz Parkinson, P. M.; D'Ammando, F.; Dermer, C. D.; Grove, J. E.; Harding, A. K.; Hays, E.; Mazziotta, M. N.; Tennant, A. F.

    2012-01-01

    The Large Area Telescope on board the Fermi satellite observed a gamma-ray flare in the Crab Nebula lasting for approximately nine days in April of 2011. The source, which at optical wavelengths has a size of ≈11 lt-yr across, doubled its gamma-ray flux within eight hours. The peak photon flux was (186 ± 6) × 10 –7 cm –2 s –1 above 100 MeV, which corresponds to a 30-fold increase compared to the average value. During the flare, a new component emerged in the spectral energy distribution, which peaked at an energy of (375 ± 26) MeV at flare maximum. The observations imply that the emission region was likely relativistically beamed toward us and that variations in its motion are responsible for the observed spectral variability.

  2. Flare Observations

    Benz Arnold O.

    2008-02-01

    Full Text Available Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays at 100 MeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, and SOHO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections (CMEs, electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristics vary from small to large flares. Recent progress also includes improved insights into the flare energy partition, on the location(s of energy release, tests of energy release scenarios and particle acceleration. The interplay of observations with theory is important to deduce the geometry and to disentangle the various processes involved. There is increasing evidence supporting reconnection of magnetic field lines as the basic cause. While this process has become generally accepted as the trigger, it is still controversial how it converts a considerable fraction of the energy into non-thermal particles. Flare-like processes may be responsible for large-scale restructuring of the magnetic field in the corona as well as for its heating. Large flares influence interplanetary space and substantially affect the Earth’s lower ionosphere. While flare scenarios have slowly converged over the past decades, every new observation still reveals major unexpected results, demonstrating that solar flares, after 150 years since their discovery, remain a complex problem of astrophysics including major unsolved questions.

  3. Flare Observations

    Benz, Arnold O.

    2017-12-01

    Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays beyond 1 GeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, SOHO, and more recently Hinode and SDO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections, electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristics vary from small to large flares. Recent progress also includes improved insights into the flare energy partition, on the location(s) of energy release, tests of energy release scenarios and particle acceleration. The interplay of observations with theory is important to deduce the geometry and to disentangle the various processes involved. There is increasing evidence supporting magnetic reconnection as the basic cause. While this process has become generally accepted as the trigger, it is still controversial how it converts a considerable fraction of the energy into non-thermal particles. Flare-like processes may be responsible for large-scale restructuring of the magnetic field in the corona as well as for its heating. Large flares influence interplanetary space and substantially affect the Earth's ionosphere. Flare scenarios have slowly converged over the past decades, but every new observation still reveals major unexpected results, demonstrating that solar flares, after 150 years since their discovery, remain a complex problem of astrophysics including major unsolved questions.

  4. Observations of photospheric magnetic fields and shear flows in flaring active regions

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

    1988-01-01

    Horizontal flows in the photosphere and subsurface convection zone move the footpoints of coronal magnetic field lines. Magnetic energy to power flares can be stored in the corona if the flows drive the fields far from the potential configuration. Videodisk movies were shown with 0.5 to 1 arcsecond resolution of the following simultaneous observations: green continuum, longitudinal magnetogram, Fe I 5576 A line center (mid-photosphere), H alpha wings, and H alpha line center. The movies show a 90 x 90 arcsecond field of view of an active region at S29, W11. When viewed at speeds of a few thousand times real-time, the photospheric movies clearly show the active region fields being distorted by a remarkable combination of systematic flows and small eruptions of new flux. Magnetic bipoles are emerging over a large area, and the polarities are systematically flowing apart. The horizontal flows were mapped in detail from the continuum movies, and these may be used to predict the future evolution of the region. The horizontal flows are not discernable in H alpha. The H alpha movies strongly suggest reconnection processes in the fibrils joining opposite polarities. When viewed in combination with the magnetic movies, the cause for this evolution is apparent: opposite polarity fields collide and partially cancel, and the fibrils reconnect above the surface. This type of reconnection, driven by subphotospheric flows, complicates the chromospheric and coronal fields, causing visible braiding and twisting of the fibrils. Some of the transient emission events in the fibrils and adjacent plage may also be related

  5. Flare stars and Pascal distribution

    Muradian, R.

    1994-07-01

    Observed statistics of stellar flares are described by Pascal or Negative Binomial Distribution. The analogy with other classes of chaotic production mechanisms such as hadronic particle multiplicity distributions and photoelectron counts from thermal sources is noticed. (author). 12 refs

  6. MAG4 Versus Alternative Techniques for Forecasting Active-Region Flare Productivity

    Falconer, David A.; Moore, Ronald L.; Barghouty, Abdulnasser F.; Khazanov, Igor

    2014-01-01

    MAG4 (Magnetogram Forecast), developed originally for NASA/SRAG (Space Radiation Analysis Group), is an automated program that analyzes magnetograms from the HMI (Helioseismic and Magnetic Imager) instrument on NASA SDO (Solar Dynamics Observatory), and automatically converts the rate (or probability) of major flares (M- and X-class), Coronal Mass Ejections (CMEs), and Solar Energetic Particle Events. MAG4 does not forecast that a flare will occur at a particular time in the next 24 or 48 hours; rather the probability of one occurring.

  7. Statistical aspects of the 1980 solar flares. 2: solar cycle activity relationships and additional remarks

    Wilson, R.M.

    1982-02-01

    Based on 1349 hydrogen alpha flares with X-ray counterparts, an investigation into the relationship between the rise time, decay time, duration, latitude, hydrogen alpha importance, and X-ray class with 2800 MHz radio emission (F2800) was accomplished. An important finding is that during 1980 both the number of hydrogen alpha importance class 1 and number of X-ray class M (and M+X) flares appeared to be rather strongly related to F2800, in a positive sense i.e., number of class 1 and class M events increased as F2800 increased

  8. Comparison of emission properties of two homologous flares in AR 11283

    Xu, Yan; Jing, Ju; Wang, Shuo; Wang, Haimin, E-mail: yx2@njit.edu [Space Weather Research Lab, Center for Solar-Terrestrial Research, New Jersey Institute of Technology 323 Martin Luther King Boulevard, Newark, NJ 07102-1982 (United States)

    2014-05-20

    Large, complex, active regions may produce multiple flares within a certain period of one or two days. These flares could occur in the same location with similar morphologies, commonly referred to as 'homologous flares'. In 2011 September, active region NOAA 11283 produced a pair of homologous flares on the 6th and 7th, respectively. Both of them were white-light (WL) flares, as captured by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory in visible continuum at 6173 Å which is believed to originate from the deep solar atmosphere. We investigate the WL emission of these X-class flares with HMI's seeing-free imaging spectroscopy. The durations of impulsive peaks in the continuum are about 4 minutes. We compare the WL with hard X-ray (HXR) observations for the September 6 flare and find a good correlation between the continuum and HXR both spatially and temporally. In absence of RHESSI data during the second flare on September 7, the derivative of the GOES soft X-ray is used and also found to be well correlated temporally with the continuum. We measure the contrast enhancements, characteristic sizes, and HXR fluxes of the twin flares, which are similar for both flares, indicating analogous triggering and heating processes. However, the September 7 flare was associated with conspicuous sunquake signals whereas no seismic wave was detected during the flare on September 6. Therefore, this comparison suggests that the particle bombardment may not play a dominant role in producing the sunquake events studied in this paper.

  9. Periodic Recurrence Patterns In X-Ray Solar Flare Appearances

    Gyenge, N.; Erdélyi, R.

    2018-06-01

    The temporal recurrence of micro-flare events is studied for a time interval before and after of major solar flares. Our sample is based on the X-ray flare observations by the Geostationary Operational Environmental Satellite (GOES) and Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The analyzed data contain 1330/301 M-class and X-class GOES/RHESSI energetic solar flares and 4062/4119 GOES/RHESSI micro-flares covering the period elapse since 2002. The temporal analysis of recurrence, by Fast Fourier Transform, of the micro-flares, shows multiple significant periods. Based on the GOES and RHESSI data, the temporal analysis also demonstrates that multiple periods manifest simultaneously in both statistical samples without any significant shift over time. In the GOES sample, the detected significant periods are: 11.33, 5.61, 3.75, 2.80, and 2.24 minutes. The RHESSI data show similar significant periods at 8.54, 5.28, 3.66, 2.88, and 2.19 minutes. The periods are interpreted as signatures of standing oscillations, with the longest period (P 1) being the fundamental and others being higher harmonic modes. The period ratio of the fundamental and higher harmonics (P 1/P N ) is also analyzed. The standing modes may be signatures of global oscillations of the entire solar atmosphere encompassing magnetized plasma from the photosphere to the corona in active regions.

  10. Dynamic Precursors of Flares in Active Region NOAA 10486 M. B. ...

    2014-12-31

    Dec 31, 2014 ... Key words. ... of potential flare indicators are, e.g., the pre-defined K-parameter describing the ... Other groups focused on the spatial and temporal resolution of the magnetic .... middle panel) between 25 October and 3 November 2003. ... 4http://www.spaceweather.com/glossary/magneticclasses.html.

  11. Solar flares

    Brown, J.C.; Smith, D.F.

    1980-01-01

    The current observational and theoretical status of solar flares as a typical astrophysical problem is reviewed with especial reference to the intense and complex energy release in large flares. Observations and their diagnostic applications are discussed in three broad areas: thermal radiation at temperatures T 5 K; thermal radiation at T > approximately 10 5 K; and non-thermal radiation and particles. Particular emphasis is given to the most recent observational discoveries such as flare γ-rays, interplanetary Langmuir waves, and the ubiquitous association of soft x-ray loops with flares, and also the progress in particle diagnostics of hard x-ray and radio bursts. The theoretical problems of primary energy release are considered in terms of both possible magnetic configuration and in plasma instabilities and the question of achieving the necessary flash power discussed. The credibility of models for the secondary redistribution through the atmosphere of the primary magnetic energy released in terms of conduction, convection, radiation and particle transport is examined. Progress made in the flare problem in the past decade is assessed and some possible reasons why no convincing solution has yet been found are considered. 296 references. (U.K.)

  12. Generation Mechanisms of Quasi-parallel and Quasi-circular Flare Ribbons in a Confined Flare

    Hernandez-Perez, Aaron; Thalmann, Julia K.; Veronig, Astrid M.; Dickson, Ewan C. [IGAM/Institute of Physics, University of Graz, A-8010 Graz (Austria); Su, Yang [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory Chinese Academy of Sciences, 2 West Beijing Road, 210008 Nanjing (China); Gömöry, Peter, E-mail: aaron.hernandez-perez@uni-graz.at [Astronomical Institute, Slovak Academy of Sciences, 05960 Tatranská Lomnica (Slovakia)

    2017-10-01

    We analyze a confined multiple-ribbon M2.1 flare (SOL2015-01-29T11:42) that originated from a fan-spine coronal magnetic field configuration, within active region NOAA 12268. The observed ribbons form in two steps. First, two primary ribbons form at the main flare site, followed by the formation of secondary ribbons at remote locations. We observe a number of plasma flows at extreme-ultraviolet temperatures during the early phase of the flare (as early as 15 minutes before the onset) propagating toward the formation site of the secondary ribbons. The secondary ribbon formation is co-temporal with the arrival of the pre-flare generated plasma flows. The primary ribbons are co-spatial with Ramaty High Energy Spectroscopic Imager ( RHESSI ) hard X-ray sources, whereas no enhanced X-ray emission is detected at the secondary ribbon sites. The (E)UV emission, associated with the secondary ribbons, peaks ∼1 minute after the last RHESSI hard X-ray enhancement. A nonlinear force-free model of the coronal magnetic field reveals that the secondary flare ribbons are not directly connected to the primary ribbons, but to regions nearby. Detailed analysis suggests that the secondary brightenings are produced due to dissipation of kinetic energy of the plasma flows (heating due to compression), and not due to non-thermal particles accelerated by magnetic reconnection, as is the case for the primary ribbons.

  13. Upstream petroleum industry flaring guide : review draft

    1999-03-01

    The Alberta requirements and expectations for upstream petroleum flaring are presented. Flaring is associated with a wide range of energy activities including oil and gas well drilling and well completion operations. The guide incorporates the recommendations made to the Alberta Energy and Utilities Board (EUB) in June 1998 by the multi-stakeholder Clean Air Strategic Alliance (CASA) on associated or solution gas flaring. Additional requirements which address flaring issues not covered in the CASA report are also included in this guide. The Guide requires a 15 per cent reduction in solution gas flare volume by the end of year 2000 from the 1996 baseline, and a 25 per cent reduction by the end of 2001. The Guide prescribes new flare performance requirements for all flares, within three years for existing solution gas flares, five years for flares at other existing permanent facilities. It sets personal consultation and public notification requirements for new and existing solution gas batteries, and new sulphur recovery requirements for facilities not covered by existing EUB regulations. The Guide also addresses the question of conflict resolution to deal with flaring concerns, the release of flaring and venting data, the proposed reduction of flare limits, progress towards minimizing requirements for electricity generators using otherwise flared gas, annual reporting to the EUB, and management framework review in 2001

  14. Solar Flares and Their Prediction

    Adams, Mitzi L.

    1999-01-01

    Solar flares and coronal mass ejection's (CMES) can strongly affect the local environment at the Earth. A major challenge for solar physics is to understand the physical mechanisms responsible for the onset of solar flares. Flares, characterized by a sudden release of energy (approx. 10(exp 32) ergs for the largest events) within the solar atmosphere, result in the acceleration of electrons, protons, and heavier ions as well as the production of electromagnetic radiation from hard X-rays to km radio waves (wavelengths approx. = 10(exp -9) cm to 10(exp 6) cm). Observations suggest that solar flares and sunspots are strongly linked. For example, a study of data from 1956-1969, reveals that approx. 93 percent of major flares originate in active regions with spots. Furthermore, the global structure of the sunspot magnetic field can be correlated with flare activity. This talk will review what we know about flare causes and effects and will discuss techniques for quantifying parameters, which may lead to a prediction of solar flares.

  15. How flares can be understood

    Severny, A.B.

    1977-01-01

    Specific features of the flare phenomenon which are important for understanding of flares are the following: (1) Fine structure of visible emission of flares, especially at the very beginning and in the pre-flare active region. This structure can be seen also in later stages of development as bright points, some of which exist from the flare beginning (Babin's observations at Crimea, 1972-1976). (2) Turbulent motion with velocities up to 250-300 km s -1 as can be estimated from broadening of emission lines. (3) Predominantly red asymmetry of emission lines in the explosive phase and during further development of flares. (4) 'Supersonic' velocities and supergravitational accelerations of separate moving masses of the flare plasma. (5) The appearance of flares in areas with high grad H, exceeding 0.1 G km -1 which is equivalent to regions of electric currents > approximately 10 11 A. (6) Strong variations of net magnetic flux through the active region, as it follows from Meudon, Crimean, and Sacramento Peak (Rust's) observations. (Auth.)

  16. Solar flare activity in 2006 - 2016 according to PAMELA and ARINA spectrometers

    Rodenko, S. A.; Borkut, I. K.; Mayorov, A. G.; Malakhov, V. V.; PAMELA Collaboration

    2018-01-01

    From 2006 to 2016 years on the board of RESURS-DK1 satellite PAMELA and ARINA cosmic rays experiments was carried out. The main goal of experiments is measurement of galactic component of cosmic rays; it also registers solar particles accelerated in powerful explosive processes on the sun (solar flares) in wide energy range. The article includes the list of solar events when PAMELA or ARINA spectrometers have registered increasing of proton flux intensities for energies more than 4 MeV.

  17. Sunspot proper motions in active region NOAA 2372 and its flare activity during SMY period of 1980 April 4-13

    Ambastha, A.; Bhatnagar, A.

    1988-01-01

    Solar Active Region NOAA 2372 was observed extensively by the Solar Maximum Mission (SMM) satellite and several ground-based observatories during 1980 April 4-13 in the Solar Maximum Year. After its birth around April 4, it underwent a rapid growth and produced a reported 84 flares in the course of its disc passage. In this paper, photospheric and chromospheric observations of this active region have been studied together with Marshall Space Flight Center magnetograms and X-ray data from HXIS aboard the SMM satellite. In particular, the relationship of the flare-productivity with sunspot proper motions and emergence of new regions of magnetic flux in the active region from its birth to its disappearance at the W-limb has been discussed. (author). 7 figures, 2 tables, 29 refs

  18. Statistical study of spatio-temporal distribution of precursor solar flares associated with major flares

    Gyenge, N.; Ballai, I.; Baranyi, T.

    2016-07-01

    The aim of the present investigation is to study the spatio-temporal distribution of precursor flares during the 24 h interval preceding M- and X-class major flares and the evolution of follower flares. Information on associated (precursor and follower) flares is provided by Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Flare list, while the major flares are observed by the Geostationary Operational Environmental Satellite (GOES) system satellites between 2002 and 2014. There are distinct evolutionary differences between the spatio-temporal distributions of associated flares in about one-day period depending on the type of the main flare. The spatial distribution was characterized by the normalized frequency distribution of the quantity δ (the distance between the major flare and its precursor flare normalized by the sunspot group diameter) in four 6 h time intervals before the major event. The precursors of X-class flares have a double-peaked spatial distribution for more than half a day prior to the major flare, but it changes to a lognormal-like distribution roughly 6 h prior to the event. The precursors of M-class flares show lognormal-like distribution in each 6 h subinterval. The most frequent sites of the precursors in the active region are within a distance of about 0.1 diameter of sunspot group from the site of the major flare in each case. Our investigation shows that the build-up of energy is more effective than the release of energy because of precursors.

  19. KEPLER FLARES. II. THE TEMPORAL MORPHOLOGY OF WHITE-LIGHT FLARES ON GJ 1243

    Davenport, James R. A.; Hawley, Suzanne L.; Johnson, Emily C.; Peraza, Jesus; Jansen, Tiffany C.; Larsen, Daniel M. [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Hebb, Leslie [Department of Physics, Hobart and William Smith Colleges, 300 Pulteney Street, Geneva, NY 14456 (United States); Wisniewski, John P.; Malatesta, Michael; Keil, Marcus; Silverberg, Steven M.; Scheffler, Matthew S.; Berdis, Jodi R. [HL Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W Brooks Street, Norman, OK 73019 (United States); Kowalski, Adam F. [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States); Hilton, Eric J., E-mail: jrad@astro.washington.edu [Universe Sandbox, 911 E. Pike Street #333, Seattle, WA 98122 (United States)

    2014-12-20

    We present the largest sample of flares ever compiled for a single M dwarf, the active M4 star GJ 1243. Over 6100 individual flare events, with energies ranging from 10{sup 29} to 10{sup 33} erg, are found in 11 months of 1 minute cadence data from Kepler. This sample is unique for its completeness and dynamic range. We have developed automated tools for finding flares in short-cadence Kepler light curves, and performed extensive validation and classification of the sample by eye. From this pristine sample of flares we generate a median flare template. This template shows that two exponential cooling phases are present during the white-light flare decay, providing fundamental constraints for models of flare physics. The template is also used as a basis function to decompose complex multi-peaked flares, allowing us to study the energy distribution of these events. Only a small number of flare events are not well fit by our template. We find that complex, multi-peaked flares occur in over 80% of flares with a duration of 50 minutes or greater. The underlying distribution of flare durations for events 10 minutes and longer appears to follow a broken power law. Our results support the idea that sympathetic flaring may be responsible for some complex flare events.

  20. KEPLER FLARES. II. THE TEMPORAL MORPHOLOGY OF WHITE-LIGHT FLARES ON GJ 1243

    Davenport, James R. A.; Hawley, Suzanne L.; Johnson, Emily C.; Peraza, Jesus; Jansen, Tiffany C.; Larsen, Daniel M.; Hebb, Leslie; Wisniewski, John P.; Malatesta, Michael; Keil, Marcus; Silverberg, Steven M.; Scheffler, Matthew S.; Berdis, Jodi R.; Kowalski, Adam F.; Hilton, Eric J.

    2014-01-01

    We present the largest sample of flares ever compiled for a single M dwarf, the active M4 star GJ 1243. Over 6100 individual flare events, with energies ranging from 10 29 to 10 33 erg, are found in 11 months of 1 minute cadence data from Kepler. This sample is unique for its completeness and dynamic range. We have developed automated tools for finding flares in short-cadence Kepler light curves, and performed extensive validation and classification of the sample by eye. From this pristine sample of flares we generate a median flare template. This template shows that two exponential cooling phases are present during the white-light flare decay, providing fundamental constraints for models of flare physics. The template is also used as a basis function to decompose complex multi-peaked flares, allowing us to study the energy distribution of these events. Only a small number of flare events are not well fit by our template. We find that complex, multi-peaked flares occur in over 80% of flares with a duration of 50 minutes or greater. The underlying distribution of flare durations for events 10 minutes and longer appears to follow a broken power law. Our results support the idea that sympathetic flaring may be responsible for some complex flare events

  1. A Multiwavelength Study of Flaring Activity in the High-energy Peaked BL Lac Object 1ES 1959+650 During 2015–2016

    Kaur, Navpreet; Chandra, S.; Baliyan, Kiran S; Sameer; Ganesh, S. [Astronomy and Astrophysics Division, Physical Research Laboratory, Ahmedabad, Gujarat 380009 (India)

    2017-09-10

    We present the results from a multiwavelength study of the flaring activity in the high-energy peaked BL Lac object 1ES 1959+650 during 2015 January–2016 June. The source underwent two major outbursts, during 2015 March and 2015 October, across the whole electromagnetic spectrum (EMS). We used data from Fermi -LAT and Swift -XRT/UVOT, and optical data from Mt. Abu InfraRed Observatory and Steward Observatory to look for possible correlations between the emissions at different energies and the nature of the variability during the flaring state. During the 2015 October outburst, the nightly averaged V -band brightest magnitude, 14.45(0.03), and faintest magnitude, 14.45(0.03), were recorded. Apart from long-term flares, rapid and short-term variabilities were noticed at all energies. Our study suggests that the flaring activities at all frequencies, with diverse flare durations and time lags, are correlated. The magnetic field strength is estimated to be 4 G using the synchrotron-cooling timescale (2.3 hr), and the upper limits on the sizes of both emission regions, γ -ray and optical, are estimated to be of the order of 10{sup 16} cm. The quasi-simultaneous flux enhancements in 15 GHz and VHE γ -ray emissions indicate a fresh injection of plasma into the jet, which interacts with a standing submillimeter core, resulting in co-spatial emissions across the EMS. The synchrotron peak shifts to higher frequency in the spectral energy distribution while the γ -ray spectra softens during the flaring. The shape of the inverse-Compton spectra indicates a change in the particle energy distribution pre- and post-flare.

  2. Gamma-Ray Flaring Activity from the Gravitationally Lensed Blazar PKS 1830-211 Observed by Fermi LAT

    Abdo, A. A.; et al.

    2015-01-23

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope routinely detects the MeV-peaked flat-spectrum radio quasar PKS 1830–211 (z = 2.507). Its apparent isotropic γ-ray luminosity (E > 100 MeV), averaged over ~3 years of observations and peaking on 2010 October 14/15 at 2.9 × 10(50) erg s(–)(1), makes it among the brightest high-redshift Fermi blazars. No published model with a single lens can account for all of the observed characteristics of this complex system. Based on radio observations, one expects time-delayed variability to follow about 25 days after a primary flare, with flux about a factor of 1.5 less. Two large γ-ray flares of PKS 1830–211 have been detected by the LAT in the considered period, and no substantial evidence for such a delayed activity was found. This allows us to place a lower limit of about 6 on the γ-ray flux ratio between the two lensed images. Swift XRT observations from a dedicated Target of Opportunity program indicate a hard spectrum with no significant correlation of X-ray flux with the γ-ray variability. The spectral energy distribution can be modeled with inverse Compton scattering of thermal photons from the dusty torus. The implications of the LAT data in terms of variability, the lack of evident delayed flare events, and different radio and γ-ray flux ratios are discussed. Microlensing effects, absorption, size and location of the emitting regions, the complex mass distribution of the system, an energy-dependent inner structure of the source, and flux suppression by the lens galaxy for one image path may be considered as hypotheses for understanding our results.

  3. Design alternatives, components key to optimum flares

    Cunha-Leite, O.

    1992-01-01

    A properly designed flare works as an emissions control system with greater than 98% combustion efficiency. The appropriate use of steam, natural gas, and air-assisted flare tips can result in smokeless combustion. Ground flare, otherwise the elevated flare is commonly chosen because it handles larger flow releases more economically. Flaring has become more complicated than just lighting up waste gas. Companies are increasingly concerned about efficiency. In addition, U.S. Occupational Safety and Health Administration (OSHA) and U.S. Environmental Protection Agency (EPA) have become more active, resulting in tighter regulations on both safety and emissions control. These regulations have resulted in higher levels of concern and involvement in safety and emissions matters, not to mention smoke, noise, glare, and odor. This first to two articles on flare design and components looks at elevated flares, flare tips, incinerator-type flares, flare pilots, and gas seals. Part 2 will examine knockout drums, liquid-seal drums, ignition systems, ground flares, vapor recovery systems, and flare noise

  4. Deep Flare Net (DeFN) Model for Solar Flare Prediction

    Nishizuka, N.; Sugiura, K.; Kubo, Y.; Den, M.; Ishii, M.

    2018-05-01

    We developed a solar flare prediction model using a deep neural network (DNN) named Deep Flare Net (DeFN). This model can calculate the probability of flares occurring in the following 24 hr in each active region, which is used to determine the most likely maximum classes of flares via a binary classification (e.g., ≥M class versus statistically predict flares, the DeFN model was trained to optimize the skill score, i.e., the true skill statistic (TSS). As a result, we succeeded in predicting flares with TSS = 0.80 for ≥M-class flares and TSS = 0.63 for ≥C-class flares. Note that in usual DNN models, the prediction process is a black box. However, in the DeFN model, the features are manually selected, and it is possible to analyze which features are effective for prediction after evaluation.

  5. The sun and solar flares

    McKenna-Lawlor, S.

    1982-01-01

    The subject is discussed under the headings: the sun's core (thermonuclear reactions, energy transfer from core through radiation zone, convection zone, photosphere, chromosphere and corona); the photosphere (convection, granulation, sunspots, magnetic fields, solar cycle, rotation of the sun); solar variability and paleoclimatic records (correlation of low solar activity with increased 14 C production in atmosphere); the chromosphere and corona (turbulence, temperature, coronal streamers, energy transfer); solar flares (cosmic rays, aurorae, spectra, velocity of flares, prominences, mechanisms of flares); the solar wind. (U.K.)

  6. Flare Seismology from SDO Observations

    Lindsey, Charles; Martinez Oliveros, Juan Carlos; Hudson, Hugh

    2011-10-01

    Some flares release intense seismic transients into the solar interior. These transients are the sole instance we know of in which the Sun's corona exerts a conspicuous influence on the solar interior through flares. The desire to understand this phenomenon has led to ambitious efforts to model the mechanisms by which energy stored in coronal magnetic fields drives acoustic waves that penetrate deep into the Sun's interior. These mechanisms potentially involve the hydrodynamic response of the chromosphere to thick-target heating by high-energy particles, radiative exchange in the chromosphere and photosphere, and Lorentz-force transients to account for acoustic energies estimated up to at 5X10^27 erg and momenta of order 6X10^19 dyne sec. An understanding of these components of flare mechanics promises more than a powerful diagnostic for local helioseismology. It could give us fundamental new insight into flare mechanics themselves. The key is appropriate observations to match the models. Helioseismic observations have identified the compact sources of transient seismic emission at the foot points of flares. The Solar Dynamics Observatory is now giving us high quality continuum-brightness and Doppler observations of acoustically active flares from HMI concurrent with high-resolution EUV observations from AIA. Supported by HXR observations from RHESSI and a broad variety of other observational resources, the SDO promises a leading role in flare research in solar cycle 24.

  7. Thermal Time Evolution of Non-Flaring Active Regions Determined by SDO/AIA

    Wright, Paul James; Hannah, Iain; Viall, Nicholeen; MacKinnon, Alexander; Ireland, Jack; Bradshaw, Stephen

    2017-08-01

    We present the pixel-level time evolution of DEM maps from SDO/AIA data using two different methods (Hannah et al. 2012; Cheung et al. 2015). These sets of Differential Emission Measure (DEM) maps allow us to determine the slopes of the DEM throughout non-flaring structures, and investigate how this changes with time, a crucial parameter in terms of how these flux tubes are being heated. We present this analysis on both real and synthetic data allowing us to understand how robustly we can recover the thermal time evolution. As this analysis also produces the time series in different temperature bands we can further investigate the underlying heating mechanisms by applying a variety of techniques to probe the frequency and nature of the heating, such as time-lag analysis (Viall & Klimchuck 2012; 2016), power spectrum analysis (Ireland et al. 2015), and Local Intermittency Measure (Dinkelaker & MacKinnon 2013a,b).

  8. Successive X-class Flares and Coronal Mass Ejections Driven by Shearing Motion and Sunspot Rotation in Active Region NOAA 12673

    Yan, X. L.; Wang, J. C.; Pan, G. M.; Kong, D. F.; Xue, Z. K.; Yang, L. H.; Li, Q. L.; Feng, X. S.

    2018-03-01

    We present a clear case study on the occurrence of two successive X-class flares, including a decade-class flare (X9.3) and two coronal mass ejections (CMEs) triggered by shearing motion and sunspot rotation in active region NOAA 12673 on 2017 September 6. A shearing motion between the main sunspots with opposite polarities began on September 5 and lasted even after the second X-class flare on September 6. Moreover, the main sunspot with negative polarity rotated around its umbral center, and another main sunspot with positive polarity also exhibited a slow rotation. The sunspot with negative polarity at the northwest of the active region also began to rotate counterclockwise before the onset of the first X-class flare, which is related to the formation of the second S-shaped structure. The successive formation and eruption of two S-shaped structures were closely related to the counterclockwise rotation of the three sunspots. The existence of a flux rope is found prior to the onset of two flares by using nonlinear force-free field extrapolation based on the vector magnetograms observed by Solar Dynamics Observatory/Helioseismic and Magnetic Image. The first flux rope corresponds to the first S-shaped structures mentioned above. The second S-shaped structure was formed after the eruption of the first flux rope. These results suggest that a shearing motion and sunspot rotation play an important role in the buildup of the free energy and the formation of flux ropes in the corona that produces solar flares and CMEs.

  9. Stellar CME candidates: towards a stellar CME-flare relation

    Paraskevi Moschou, Sofia; Drake, Jeremy J.; Cohen, Ofer; Alvarado-Gomez, Julian D.; Garraffo, Cecilia

    2018-06-01

    For decades the Sun has been the only star that allowed for direct CME observations. Recently, with the discovery of multiple extrasolar systems, it has become imperative that the role of stellar CMEs be assessed in the context of exoplanetary habitability. Solar CMEs and flares show a higher association with increasing flaring energy, with strong flares corresponding to large and fast CMEs. As argued in earlier studies, extrasolar environments around active stars are potentially dominated by CMEs, as a result of their extreme flaring activity. This has strong implications for the energy budget of the system and the atmospheric erosion of orbiting planets.Nevertheless, with current instrumentation we are unable to directly observe CMEs in even the closest stars, and thus we have to look for indirect techniques and observational evidence and signatures for the eruption of stellar CMEs. There are three major observational techniques for tracing CME signatures in other stellar systems, namely measuring Type II radio bursts, Doppler shifts in UV/optical lines or transient absorption in the X-ray spectrum. We present observations of the most probable stellar CME candidates captured so far and examine the different observational techniques used together with their levels of uncertainty. Assuming that they were CMEs, we try to asses their kinematic and energetic characteristics and place them in an extension of the well-established solar CME-flare energy scaling law. We finish by discussing future observations for direct measurements.

  10. Flare continuum

    Robinson, R.D.

    1985-01-01

    This paper reviews the metre-wave continuum radiation which is related to similar solar emissions observed in the decimetre and centimetre spectral regions. This type of emission, known as Flare Contiuum, is related to the radio bursts of types II and IV. After summarising the history of the phenomenon and reviewing the observational work, the author discusses the various possible radiation mechanisms and their relation to the solar corona, the interplanetary medium and related regions. The theoretical topics covered include the role of high-energy particles, the trapping of such particles, gyro-synchrotron radiation, polarization and plasma interactions. (U.K.)

  11. INFERENCE OF HEATING PROPERTIES FROM “HOT” NON-FLARING PLASMAS IN ACTIVE REGION CORES. I. SINGLE NANOFLARES

    Barnes, W. T.; Bradshaw, S. J. [Department of Physics and Astronomy, Rice University, Houston, TX 77251-1892 (United States); Cargill, P. J., E-mail: will.t.barnes@rice.edu [Space and Atmospheric Physics, The Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom)

    2016-09-20

    The properties that are expected of “hot” non-flaring plasmas due to nanoflare heating in active regions are investigated using hydrodynamic modeling tools, including a two-fluid development of the Enthalpy Based Thermal Evolution of Loops code. Here we study a single nanoflare and show that while simple models predict an emission measure distribution extending well above 10 MK, which is consistent with cooling by thermal conduction, many other effects are likely to limit the existence and detectability of such plasmas. These include: differential heating between electrons and ions, ionization non-equilibrium, and for short nanoflares, the time taken for the coronal density to increase. The most useful temperature range to look for this plasma, often called the “smoking gun” of nanoflare heating, lies between 10{sup 6.6} and 10{sup 7} K. Signatures of the actual heating may be detectable in some instances.

  12. The magnetic field of active region 11158 during the 2011 February 12-17 flares: Differences between photospheric extrapolation and coronal forward-fitting methods

    Aschwanden, Markus J.; Sun, Xudong; Liu, Yang

    2014-01-01

    We developed a coronal nonlinear force-free field (COR-NLFFF) forward-fitting code that fits an approximate nonlinear force-free field (NLFFF) solution to the observed geometry of automatically traced coronal loops. In contrast to photospheric NLFFF codes, which calculate a magnetic field solution from the constraints of the transverse photospheric field, this new code uses coronal constraints instead, and this way provides important information on systematic errors of each magnetic field calculation method, as well as on the non-force-freeness in the lower chromosphere. In this study we applied the COR-NLFFF code to NOAA Active Region 11158, during the time interval of 2011 February 12-17, which includes an X2.2 GOES-class flare plus 35 M- and C-class flares. We calculated the free magnetic energy with a 6 minute cadence over 5 days. We find good agreement between the two types of codes for the total nonpotential E N and potential energy E P but find up to a factor of 4 discrepancy in the free energy E free = E N – E P and up to a factor of 10 discrepancy in the decrease of the free energy ΔE free during flares. The coronal NLFFF code exhibits a larger time variability and yields a decrease of free energy during the flare that is sufficient to satisfy the flare energy budget, while the photospheric NLFFF code shows much less time variability and an order of magnitude less free-energy decrease during flares. The discrepancy may partly be due to the preprocessing of photospheric vector data but more likely is due to the non-force-freeness in the lower chromosphere. We conclude that the coronal field cannot be correctly calculated on the basis of photospheric data alone and requires additional information on coronal loop geometries.

  13. How is symptom flare defined in musculoskeletal conditions: A systematic review.

    Costa, Nathalia; Ferreira, Manuela L; Cross, Marita; Makovey, Joanna; Hodges, Paul W

    2018-01-31

    To systematically review the definitions for "flare" in musculoskeletal conditions, the derivation processes, and validation of definitions for the 12 most burdensome musculoskeletal conditions. A literature search was conducted in MEDLINE, EMBASE, CINAHL, AMED, PsycInfo and Lilacs to identify studies that investigated derivation or validation of a flare definition, which we considered as a phrase or group of domains. Reports of derivation of flare definitions were identified for 9/12 musculoskeletal conditions. Validation of flare definitions was initiated for 4/12. For each condition, different derivation and validation methods have been used, with variable levels of consumer involvement, and in some cases different groups have worked on the process in parallel. Although some flare definitions began simply as "symptom worsening" or "change in treatment", most evolved into multidimensional definitions that include: pain, impact on function, joint symptoms, and emotional elements. Frequently initial attempts to create phrase to define the term flare evolved into consensus on the breadth of domains involved. Validation has compared flare definitions/domains against measures of disease activity, clinicians' diagnosis, response to drug therapy, or a combination. This review suggests that greater characterisation and definition of flares in musculoskeletal conditions are linked to the inclusion of multiple perspectives, multifaceted domains and compound comparators for their validation. Further work is required to optimise and test the derived definitions for most musculoskeletal conditions. As some elements are disease-specific, flare definitions cannot be extrapolated to other conditions. Research regarding flare in back pain (most burdensome disease) is limited. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Lower atmosphere of solar flares; Proceedings of the Solar Maximum Mission Symposium, Sunspot, NM, Aug. 20-24, 1985

    Neidig, D.F.

    1986-01-01

    The topics discussed by the present conference encompass the chromospheric flare phenomenon, white light flares, UV emission and the flare transition region, the flare corona and high energy emissions, stellar flares, and flare energy release and transport. Attention is given to radiative shocks and condensation in flares, impulsive brightening of H-alpha flare points, the structure and response of the chromosphere to radiation backwarming during solar flares, the interpretation of continuum emissions in white light flares, and the radiation properties of solar plasmas. Also discussed are EUV images of a solar flare and C III intensity, an active region survey in H-alpha and X-rays, dynamic thermal plasma conditions in large flares, the evolution of the flare mechanism in dwarf stars, the evidence concerning electron beams in solar flares, the energetics of the nonlinear tearing mode, macroscopic electric fields during two-ribbon flares, and the low temperature signatures of energetic particles

  15. Influences of misprediction costs on solar flare prediction

    Huang, Xin; Wang, HuaNing; Dai, XingHua

    2012-10-01

    The mispredictive costs of flaring and non-flaring samples are different for different applications of solar flare prediction. Hence, solar flare prediction is considered a cost sensitive problem. A cost sensitive solar flare prediction model is built by modifying the basic decision tree algorithm. Inconsistency rate with the exhaustive search strategy is used to determine the optimal combination of magnetic field parameters in an active region. These selected parameters are applied as the inputs of the solar flare prediction model. The performance of the cost sensitive solar flare prediction model is evaluated for the different thresholds of solar flares. It is found that more flaring samples are correctly predicted and more non-flaring samples are wrongly predicted with the increase of the cost for wrongly predicting flaring samples as non-flaring samples, and the larger cost of wrongly predicting flaring samples as non-flaring samples is required for the higher threshold of solar flares. This can be considered as the guide line for choosing proper cost to meet the requirements in different applications.

  16. Flaring fix: better technologies green flaring

    Stastny, P.

    2004-01-01

    Recent advances in reducing solution gas flaring and venting are discussed, highlighting the 2002 report of the Clean Air Strategic Alliance (CASA) and its 39 recommendations targeting a 50 per cent reduction in flaring from a 1996 baseline. Much of the improvement to date (62 per cent at the end of 2002 on an annual basis) has come from collecting and sending gas down pipelines for processing, but improvements in technologies such as incineration, in combustion efficiency, and the use of micro-turbines, also helped to make a difference. Improvements in smokeless flares, through the addition of a special flare tip to flare stacks, has similarly contributed to higher combustion efficiency, and further improvements are expected from sonic flare technology currently under development. Expectations are also high for advances in incinerator technology, particularly enclosed burner systems, which almost completely burn flare gas while having no visible flame, smoke or odor

  17. Dynamics of flare sprays

    Tandberg-Hanssen, E.; Hansen, R.T.

    1980-01-01

    During solar cycle No. 20 new insight into the flare-spray phenomenon has been attained due to several innovations in solar optical-observing techniques (higher spatial resolution cinema-photography, tunable pass-band filters, multi-slit spectroscopy and extended angular field coronographs). From combined analysis of 13 well-observed sprays which occured between 1969-1974 we conclude that (i) the spray material originates from a preexisting active region filament which undergoes increased absorption some tens of minutes prior to the abrupt chromospheric brightening at the 'flare-start', and (ii) the spray material is confined within a steadily expanding, loop-shaped (presumably magnetically controlled) envelope with part of the material draining back down along one or both legs of the loop. (orig.)

  18. The comparison of microdose flare-up and multiple dose antagonist protocols based on hCG day estradiol (E2), progesterone (P) and P/E2 ratio among poor responder patients in ICSI-ET cycles.

    Cicek, M N; Kahyaoglu, I; Kahyaoglu, S

    2015-02-01

    Elevated progesterone levels surpassing exact treshold values impede endometrial receptivity and decrease clinical pregnancy rates in different responder patients during assisted reproductive techniques. A progesterone (P): estradiol (E2) ratio of > 1 on the day of hCG administration has also been suggested to be a manifestation of low ovarian reserve. The clinical significance of P/E2 ratio on the day of hCG administration was investigated among poor responder patients. Based on the ESHRE Bologna consensus criteria related to poor ovarian response diagnosis, 48 poor responder patients were treated with the microdose flare-up regimen and 34 patients were treated with the multiple-dose GnRH antagonist protocol. All patients were destined to perform a ICSI-ET procedure at the end of the stimulation protocols. Progesterone levels and P/E2 ratios have been detected during controlled ovarian hyperstimulation. In the microdose flare-up group; the duration of stimulation, total gonadotropin dose used and hCG day E2 levels were significantly higher than the multiple dose antagonist group. However, the mean hCG day P/E2 rate in the microdose flare-up group was less than that in the multiple-dose antagonist group. The clinical pregnancy rates were non significantly higher in the multiple dose antagonist protocol group than in microdose flare-up group. Impaired endometrial receptivity caused by elevated P levels results with lower pregnancy rates. Regardless of the selected stimulation protocol, poor responder patients are not prone to exhibit high P and E2 secretion. Increased P/E2 ratio of > 1 on hCG day has limited value to predict cycle outcomes in poor responder patients because of ovarian follicle depletion.

  19. THE IMPLICATIONS OF M DWARF FLARES ON THE DETECTION AND CHARACTERIZATION OF EXOPLANETS AT INFRARED WAVELENGTHS

    Tofflemire, Benjamin M.; Wisniewski, John P.; Kowalski, Adam F.; Schmidt, Sarah J.; Kundurthy, Praveen; Hilton, Eric J.; Hawley, Suzanne L. [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195 (United States); Holtzman, Jon A., E-mail: tofflb@u.washington.edu, E-mail: jwisnie@u.washington.edu [Department of Astronomy, New Mexico State University, Box 30001, Las Cruces, NM 880033 (United States)

    2012-01-15

    We present the results of an observational campaign which obtained high-cadence, high-precision, simultaneous optical and IR photometric observations of three M dwarf flare stars for 47 hr. The campaign was designed to characterize the behavior of energetic flare events, which routinely occur on M dwarfs, at IR wavelengths to millimagnitude precision, and quantify to what extent such events might influence current and future efforts to detect and characterize extrasolar planets surrounding these stars. We detected and characterized four highly energetic optical flares having U-band total energies of {approx}7.8 Multiplication-Sign 10{sup 30} to {approx}1.3 Multiplication-Sign 10{sup 32} erg, and found no corresponding response in the J, H, or Ks bandpasses at the precision of our data. For active dM3e stars, we find that a {approx}1.3 Multiplication-Sign 10{sup 32} erg U-band flare ({Delta}U{sub max} {approx} 1.5 mag) will induce <8.3 (J), <8.5 (H), and <11.7 (Ks) mmag of a response. A flare of this energy or greater should occur less than once per 18 hr. For active dM4.5e stars, we find that a {approx}5.1 Multiplication-Sign 10{sup 31} erg U-band flare ({Delta}U{sub max} {approx} 1.6 mag) will induce <7.8 (J), <8.8 (H), and <5.1 (Ks) mmag of a response. A flare of this energy or greater should occur less than once per 10 hr. No evidence of stellar variability not associated with discrete flare events was observed at the level of {approx}3.9 mmag over 1 hr timescales and at the level of {approx}5.6 mmag over 7.5 hr timescales. We therefore demonstrate that most M dwarf stellar activity and flares will not influence IR detection and characterization studies of M dwarf exoplanets above the level of {approx}5-11 mmag, depending on the filter and spectral type. We speculate that the most energetic megaflares on M dwarfs, which occur at rates of once per month, are likely to be easily detected in IR observations with sensitivity of tens of millimagnitudes. We also

  20. Models for stellar flares

    Cram, L.E.; Woods, D.T.

    1982-01-01

    We study the response of certain spectral signatures of stellar flares (such as Balmer line profiles and the broad-band continuum) to changes in atmospheric structure which might result from physical processes akin to those thought to occur in solar flares. While each physical process does not have a unique signature, we can show that some of the observed properties of stellar flares can be explained by a model which involves increased pressures and temperatures in the flaring stellar chromosphere. We suggest that changes in stellar flare area, both with time and with depth in the atmosphere, may play an important role in producing the observed flare spectrum

  1. INFERENCE OF HEATING PROPERTIES FROM “HOT” NON-FLARING PLASMAS IN ACTIVE REGION CORES. II. NANOFLARE TRAINS

    Barnes, W. T.; Bradshaw, S. J. [Department of Physics and Astronomy, Rice University, Houston, TX 77251-1892 (United States); Cargill, P. J., E-mail: will.t.barnes@rice.edu, E-mail: stephen.bradshaw@rice.edu, E-mail: p.cargill@imperial.ac.uk [Space and Atmospheric Physics, The Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom)

    2016-12-20

    Despite its prediction over two decades ago, the detection of faint, high-temperature (“hot”) emission due to nanoflare heating in non-flaring active region cores has proved challenging. Using an efficient two-fluid hydrodynamic model, this paper investigates the properties of the emission expected from repeating nanoflares (a nanoflare train) of varying frequency as well as the separate heating of electrons and ions. If the emission measure distribution (EM(T)) peaks at T = T{sub m} , we find that EM(T{sub m}) is independent of details of the nanoflare train, and EM(T) above and below T{sub m} reflects different aspects of the heating. Below T{sub m} , the main influence is the relationship of the waiting time between successive nanoflares to the nanoflare energy. Above T{sub m}, power-law nanoflare distributions lead to an extensive plasma population not present in a mono-energetic train. Furthermore, in some cases, characteristic features are present in EM(T). Such details may be detectable given adequate spectral resolution and a good knowledge of the relevant atomic physics. In the absence of such resolution we propose some metrics that can be used to infer the presence of “hot” plasma.

  2. H-alpha Proxies for EIT Crinkles: Further Evidence for Pre-Flare "Breakout"-Type Activity in an Ejective Solar Eruption

    Sterling, Alphonse C.; Moore, R. L.; Qiu, J.; Wang, H.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    We present Halpha observations from Big Bear Solar Observatory of an eruptive flare in NOAA AR 8210, occurring near 22:30 UT on 1998 May 1. Previously, using the EUV Imaging Telescope (EIT) on the SOHO spacecraft, we found that a pattern of transient, localized brightenings, which we call "EIT crinkles," appears in the neighborhood of the eruption near the time of flare onset. These EIT crinkles occur at a location in the active region well separated from the sheared core magnetic fields, which is where the most intense features of the eruption are concentrated. We also previously found that high-cadence images from the Soft X-ray Telescope (SXT) on Yohkoh indicate that soft X-ray intensity enhancements in the core begin after the start of the EIT crinkles. With the Halpha data, we find remote flare brightening counterparts to the EIT crinkles. Lightcurves as functions of time of various areas of the active region show that several of the remote flare brightenings undergo intensity increases prior to onset of principle brightenings in the core region, consistent with our earlier findings from EIT and SXT data. These timing relationships are consistent with the eruption onset mechanism known as the breakout model, introduced by Antiochos and colleagues, which proposes that eruptions begin with reconnection at a magnetic null high above the core region. Our observations are also consistent with other proposed mechanisms which do not involve early reconnection in the core region. As a corollary, our observations are not consistent with the so-called tether cutting models, which say that the eruption begins with reconnection in the core. The Halpha data further show that a filament in the core region becomes activated near the time of EIT crinkle onset, but little if any of the filament actually erupts, despite the presence of a halo Coronal Mass Ejection (CME) associated with this event.

  3. Flare Prediction Using Photospheric and Coronal Image Data

    Jonas, Eric; Bobra, Monica; Shankar, Vaishaal; Todd Hoeksema, J.; Recht, Benjamin

    2018-03-01

    The precise physical process that triggers solar flares is not currently understood. Here we attempt to capture the signature of this mechanism in solar-image data of various wavelengths and use these signatures to predict flaring activity. We do this by developing an algorithm that i) automatically generates features in 5.5 TB of image data taken by the Solar Dynamics Observatory of the solar photosphere, chromosphere, transition region, and corona during the time period between May 2010 and May 2014, ii) combines these features with other features based on flaring history and a physical understanding of putative flaring processes, and iii) classifies these features to predict whether a solar active region will flare within a time period of T hours, where T = 2 and 24. Such an approach may be useful since, at the present time, there are no physical models of flares available for real-time prediction. We find that when optimizing for the True Skill Score (TSS), photospheric vector-magnetic-field data combined with flaring history yields the best performance, and when optimizing for the area under the precision-recall curve, all of the data are helpful. Our model performance yields a TSS of 0.84 ±0.03 and 0.81 ±0.03 in the T = 2- and 24-hour cases, respectively, and a value of 0.13 ±0.07 and 0.43 ±0.08 for the area under the precision-recall curve in the T=2- and 24-hour cases, respectively. These relatively high scores are competitive with previous attempts at solar prediction, but our different methodology and extreme care in task design and experimental setup provide an independent confirmation of these results. Given the similar values of algorithm performance across various types of models reported in the literature, we conclude that we can expect a certain baseline predictive capacity using these data. We believe that this is the first attempt to predict solar flares using photospheric vector-magnetic field data as well as multiple wavelengths of image

  4. The thermal phase of solar flares

    Hirayama, Tadashi

    1979-01-01

    This paper is described on the observation of the flares, and then the numerical simulation on the structural change in the corona and the chromosphere during the flare is briefly discussed. Most of the flares occur on the active region where the density and the electron temperature are higher than those in the quiet region. The temperature and density increase after the flare started. The temperature of the pre-flare chromosphere is about 6000 K, and it rises during the flare. The temperature of the transition region is about 10 5 K, and the gas pressure increases more than one order of magnitude during the flare. Sometimes, the flaring in the photosphere is observed. Large amount of mass ejected at the time of the flare is observed. Most probable energy source of the flare is the magnetic energy contained in the form of electric current. Liberation of this energy into the corona is discussed in this paper. It is assumed that a column of unit area is standing vertically in the corona, the top being closed. A hydrostatic model of the corona-chromosphere is constructed, in which the heat source is assumed to be in the corona. As the results of calculation, it can be said that the temperature of the flaring corona does not depend upon the liberated energy, the density in the corona increases proportionally to the energy, and particles are supplied from the chromosphere with the upward velocity of about 100 km/s. The gas pressure of the transition region can become up to three orders of magnitude larger. All these are consistent with the observation. Extension of this calculation is also performed. (Kato, T.)

  5. Magnetic transients in flares

    Zirin, H.; Tanaka, K.

    1981-01-01

    We present data on magnetic transients (mgtr's) observed in flares on 1980 July 1 and 5 with Big Bear videomagnetograph (VMG). The 1980 July 1 event was a white light flare in which a strong bipolar mgtr was observed, and a definite change in the sunspots occurred at the time of the flare. In the 1980 July 5 flare, a mgtr was observed in only one polarity, and, although no sunspot changes occurred simultaneous with the flare, major spot changes occurred in a period of hours

  6. Quasi-static three-dimensional magnetic field evolution in solar active region NOAA 11166 associated with an X1.5 flare

    Vemareddy, P.; Wiegelmann, T.

    2014-01-01

    We study the quasi-static evolution of coronal magnetic fields constructed from the non-linear force-free field (NLFFF) approximation aiming to understand the relation between the magnetic field topology and ribbon emission during an X1.5 flare in active region (AR) NOAA 11166. The flare with a quasi-elliptical and two remote ribbons occurred on 2011 March 9 at 23:13 UT over a positive flux region surrounded by negative flux at the center of the bipolar AR. Our analysis of the coronal magnetic structure with potential and NLFFF solutions unveiled the existence of a single magnetic null point associated with a fan-spine topology and is co-spatial with the hard X-ray source. The footpoints of the fan separatrix surface agree with the inner edge of the quasi-elliptical ribbon and the outer spine is linked to one of the remote ribbons. During the evolution, the slow footpoint motions stressed the field lines along the polarity inversion line and caused electric current layers in the corona around the fan separatrix surface. These current layers trigger magnetic reconnection as a consequence of dissipating currents, which are visible as cusp-shaped structures at lower heights. The reconnection process reorganized the magnetic field topology whose signatures are observed at the separatrices/quasi-separatrix layer structure in both the photosphere and the corona during the pre-to-post flare evolution. In agreement with previous numerical studies, our results suggest that the line-tied footpoint motions perturb the fan-spine system and cause null point reconnection, which eventually causes the flare emission at the footpoints of the field lines.

  7. Elongation of Flare Ribbons

    Qiu, Jiong; Longcope, Dana W. [Department of Physics, Montana State University, Bozeman MT (United States); Cassak, Paul A. [Department of Physics and Astronomy, West Virginia University, Morgantown WV (United States); Priest, Eric R. [School of Mathematics and Statistics, University of St. Andrews, Fife KY16 9SS, Scotland (United Kingdom)

    2017-03-20

    We present an analysis of the apparent elongation motion of flare ribbons along the polarity inversion line (PIL), as well as the shear of flare loops in several two-ribbon flares. Flare ribbons and loops spread along the PIL at a speed ranging from a few to a hundred km s{sup −1}. The shear measured from conjugate footpoints is consistent with the measurement from flare loops, and both show the decrease of shear toward a potential field as a flare evolves and ribbons and loops spread along the PIL. Flares exhibiting fast bidirectional elongation appear to have a strong shear, which may indicate a large magnetic guide field relative to the reconnection field in the coronal current sheet. We discuss how the analysis of ribbon motion could help infer properties in the corona where reconnection takes place.

  8. Statistical Distributions of Optical Flares from Gamma-Ray Bursts

    Yi, Shuang-Xi; Yu, Hai; Wang, F. Y.; Dai, Zi-Gao

    2017-01-01

    We statistically study gamma-ray burst (GRB) optical flares from the Swift /UVOT catalog. We compile 119 optical flares, including 77 flares with redshift measurements. Some tight correlations among the timescales of optical flares are found. For example, the rise time is correlated with the decay time, and the duration time is correlated with the peak time of optical flares. These two tight correlations indicate that longer rise times are associated with longer decay times of optical flares and also suggest that broader optical flares peak at later times, which are consistent with the corresponding correlations of X-ray flares. We also study the frequency distributions of optical flare parameters, including the duration time, rise time, decay time, peak time, and waiting time. Similar power-law distributions for optical and X-ray flares are found. Our statistic results imply that GRB optical flares and X-ray flares may share the similar physical origin, and both of them are possibly related to central engine activities.

  9. Statistical Distributions of Optical Flares from Gamma-Ray Bursts

    Yi, Shuang-Xi [College of Physics and Engineering, Qufu Normal University, Qufu 273165 (China); Yu, Hai; Wang, F. Y.; Dai, Zi-Gao, E-mail: fayinwang@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)

    2017-07-20

    We statistically study gamma-ray burst (GRB) optical flares from the Swift /UVOT catalog. We compile 119 optical flares, including 77 flares with redshift measurements. Some tight correlations among the timescales of optical flares are found. For example, the rise time is correlated with the decay time, and the duration time is correlated with the peak time of optical flares. These two tight correlations indicate that longer rise times are associated with longer decay times of optical flares and also suggest that broader optical flares peak at later times, which are consistent with the corresponding correlations of X-ray flares. We also study the frequency distributions of optical flare parameters, including the duration time, rise time, decay time, peak time, and waiting time. Similar power-law distributions for optical and X-ray flares are found. Our statistic results imply that GRB optical flares and X-ray flares may share the similar physical origin, and both of them are possibly related to central engine activities.

  10. A New Paradigm for Flare Particle Acceleration

    Guidoni, Silvina E.; Karpen, Judith T.; DeVore, C. Richard

    2017-08-01

    The mechanism that accelerates particles to the energies required to produce the observed high-energy impulsive emission and its spectra in solar flares is not well understood. Here, we propose a first-principle-based model of particle acceleration that produces energy spectra that closely resemble those derived from hard X-ray observations. Our mechanism uses contracting magnetic islands formed during fast reconnection in solar flares to accelerate electrons, as first proposed by Drake et al. (2006) for kinetic-scale plasmoids. We apply these ideas to MHD-scale islands formed during fast reconnection in a simulated eruptive flare. A simple analytic model based on the particles’ adiabatic invariants is used to calculate the energy gain of particles orbiting field lines in our ultrahigh-resolution, 2.5D, MHD numerical simulation of a solar eruption (flare + coronal mass ejection). Then, we analytically model electrons visiting multiple contracting islands to account for the observed high-energy flare emission. Our acceleration mechanism inherently produces sporadic emission because island formation is intermittent. Moreover, a large number of particles could be accelerated in each macroscopic island, which may explain the inferred rates of energetic-electron production in flares. We conclude that island contraction in the flare current sheet is a promising candidate for electron acceleration in solar eruptions. This work was supported in part by the NASA LWS and H-SR programs..

  11. Solar Flares: Magnetohydrodynamic Processes

    Kazunari Shibata

    2011-12-01

    Full Text Available This paper outlines the current understanding of solar flares, mainly focused on magnetohydrodynamic (MHD processes responsible for producing a flare. Observations show that flares are one of the most explosive phenomena in the atmosphere of the Sun, releasing a huge amount of energy up to about 10^32 erg on the timescale of hours. Flares involve the heating of plasma, mass ejection, and particle acceleration that generates high-energy particles. The key physical processes for producing a flare are: the emergence of magnetic field from the solar interior to the solar atmosphere (flux emergence, local enhancement of electric current in the corona (formation of a current sheet, and rapid dissipation of electric current (magnetic reconnection that causes shock heating, mass ejection, and particle acceleration. The evolution toward the onset of a flare is rather quasi-static when free energy is accumulated in the form of coronal electric current (field-aligned current, more precisely, while the dissipation of coronal current proceeds rapidly, producing various dynamic events that affect lower atmospheres such as the chromosphere and photosphere. Flares manifest such rapid dissipation of coronal current, and their theoretical modeling has been developed in accordance with observations, in which numerical simulations proved to be a strong tool reproducing the time-dependent, nonlinear evolution of a flare. We review the models proposed to explain the physical mechanism of flares, giving an comprehensive explanation of the key processes mentioned above. We start with basic properties of flares, then go into the details of energy build-up, release and transport in flares where magnetic reconnection works as the central engine to produce a flare.

  12. Motion of matter in flare loops of the solar disc

    Xu Ao-ao

    1987-01-01

    By using the optical observation data of a Class 3B double-ribbon flare obtained on July 14, 1980 at the Yunan Observatory, and the x-ray result from the SMM satellite for the same flare, the law of motion of matter in the flare loops of the solar disc is discussed. First, the solar disc positions from the Hα and x-ray images for the flare were compared, and the altitude of the flare loop was determined according to projection effects. Second, the line-of-sight velocity distribution in the region of flare activity due to the falling of matter in the flare loop was estimated theoretically. The result agreed with the observed data

  13. High-resolution Observations of Flares in an Arch Filament System

    Su, Yingna; Liu, Rui; Li, Shangwei; Cao, Wenda; Ahn, Kwangsu; Ji, Haisheng

    2018-03-01

    We study five sequential solar flares (SOL2015-08-07) occurring in Active Region 12396 observed with the Goode Solar Telescope (GST) at the Big Bear Solar Observatory, complemented by Interface Region Imaging Spectrograph and SDO observations. The main flaring region is an arch filament system (AFS) consisting of multiple bundles of dark filament threads enclosed by semicircular flare ribbons. We study the magnetic configuration and evolution of the active region by constructing coronal magnetic field models based on SDO/HMI magnetograms using two independent methods, i.e., the nonlinear force-free field (NLFFF) extrapolation and the flux rope insertion method. The models consist of multiple flux ropes with mixed signs of helicity, i.e., positive (negative) in the northern (southern) region, which is consistent with the GST observations of multiple filament bundles. The footprints of quasi-separatrix layers (QSLs) derived from the extrapolated NLFFF compare favorably with the observed flare ribbons. An interesting double-ribbon fine structure located at the east border of the AFS is consistent with the fine structure of the QSL’s footprint. Moreover, magnetic field lines traced along the semicircular footprint of a dome-like QSL surrounding the AFS are connected to the regions of significant helicity and Poynting flux injection. The maps of magnetic twist show that positive twist became dominant as time progressed, which is consistent with the injection of positive helicity before the flares. We hence conclude that these circular shaped flares are caused by 3D magnetic reconnection at the QSLs associated with the AFS possessing mixed signs of helicity.

  14. Solar Flare Aimed at Earth

    2002-01-01

    At the height of the solar cycle, the Sun is finally displaying some fireworks. This image from the Solar and Heliospheric Observatory (SOHO) shows a large solar flare from June 6, 2000 at 1424 Universal Time (10:24 AM Eastern Daylight Savings Time). Associated with the flare was a coronal mass ejection that sent a wave of fast moving charged particles straight towards Earth. (The image was acquired by the Extreme ultaviolet Imaging Telescope (EIT), one of 12 instruments aboard SOHO) Solar activity affects the Earth in several ways. The particles generated by flares can disrupt satellite communications and interfere with power transmission on the Earth's surface. Earth's climate is tied to the total energy emitted by the sun, cooling when the sun radiates less energy and warming when solar output increases. Solar radiation also produces ozone in the stratosphere, so total ozone levels tend to increase during the solar maximum. For more information about these solar flares and the SOHO mission, see NASA Science News or the SOHO home page. For more about the links between the sun and climate change, see Sunspots and the Solar Max. Image courtesy SOHO Extreme ultaviolet Imaging Telescope, ESA/NASA

  15. WHITE-LIGHT FLARES ON CLOSE BINARIES OBSERVED WITH KEPLER

    Gao, Qing; Xin, Yu; Liu, Ji-Feng; Zhang, Xiao-Bin; Gao, Shuang

    2016-01-01

    Based on Kepler data, we present the results of a search for white light flares on 1049 close binaries. We identify 234 flare binaries, of which 6818 flares are detected. We compare the flare-binary fraction in different binary morphologies (“detachedness”). The result shows that the fractions in over-contact and ellipsoidal binaries are approximately 10%–20% lower than those in detached and semi-detached systems. We calculate the binary flare activity level (AL) of all the flare binaries, and discuss its variations along the orbital period ( P orb ) and rotation period ( P rot , calculated for only detached binaries). We find that the AL increases with decreasing P orb or P rot , up to the critical values at P orb ∼ 3 days or P rot ∼ 1.5 days, and thereafter the AL starts decreasing no matter how fast the stars rotate. We examine the flaring rate as a function of orbital phase in two eclipsing binaries on which a large number of flares are detected. It appears that there is no correlation between flaring rate and orbital phase in these two binaries. In contrast, when we examine the function with 203 flares on 20 non-eclipse ellipsoidal binaries, bimodal distribution of amplitude-weighted flare numbers shows up at orbital phases 0.25 and 0.75. Such variation could be larger than what is expected from the cross section modification.

  16. MOST OBSERVATIONS OF OUR NEAREST NEIGHBOR: FLARES ON PROXIMA CENTAURI

    Davenport, James R. A. [Department of Physics and Astronomy, Western Washington University, 516 High Street, Bellingham, WA 98225 (United States); Kipping, David M. [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Sasselov, Dimitar [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Matthews, Jaymie M. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Cameron, Chris [Department of Mathematics, Physics and Geology, Cape Breton University, 1250 Grand Lake Road, Sydney, NS B1P 6L2 (Canada)

    2016-10-01

    We present a study of white-light flares from the active M5.5 dwarf Proxima Centauri using the Canadian microsatellite Microvariability and Oscillations of STars . Using 37.6 days of monitoring data from 2014 to 2015, we have detected 66 individual flare events, the largest number of white-light flares observed to date on Proxima Cen. Flare energies in our sample range from 10{sup 29} to 10{sup 31.5} erg. The flare rate is lower than that of other classic flare stars of a similar spectral type, such as UV Ceti, which may indicate Proxima Cen had a higher flare rate in its youth. Proxima Cen does have an unusually high flare rate given its slow rotation period, however. Extending the observed power-law occurrence distribution down to 10{sup 28} erg, we show that flares with flux amplitudes of 0.5% occur 63 times per day, while superflares with energies of 10{sup 33} erg occur ∼8 times per year. Small flares may therefore pose a great difficulty in searches for transits from the recently announced 1.27 M {sub ⊕} Proxima b, while frequent large flares could have significant impact on the planetary atmosphere.

  17. Long-term hemispheric variation of the flare index

    Feng Song; Deng Lin-Hua; Xu Shi-Chun

    2013-01-01

    The long-term hemispheric variation of the flare index is investigated. It is found that, (1) the phase difference of the flare index between the northern and southern hemispheres is about 6–7 months, which is near the time delay between flare activity and sunspot activity; (2) both the dominant and phase-leading hemisphere of the flare index is the northern hemisphere in the considered time interval, implying that the hemispheric asynchrony of solar activity has a close connection with the N-S asymmetry of solar activity. (research papers)

  18. Microdose gonadotropin-releasing hormone agonist flare-up protocol versus multiple dose gonadotropin-releasing hormone antagonist protocol in poor responders undergoing intracytoplasmic sperm injection-embryo transfer cycle.

    Kahraman, Korhan; Berker, Bulent; Atabekoglu, Cem Somer; Sonmezer, Murat; Cetinkaya, Esra; Aytac, Rusen; Satiroglu, Hakan

    2009-06-01

    To compare the efficacy of microdose GnRH agonist (GnRH-a) flare-up and multiple dose GnRH antagonist protocols in patients who have a poor response to a long luteal GnRH-a protocol. Prospective, randomized, clinical study. University hospital. Forty-two poor responder patients undergoing intracytoplasmic sperm injection (ICSI)-embryo transfer cycle. Twenty-one patients received microdose leuprolide acetate (LA) (50 microg twice daily) starting on the second day of withdrawal bleeding. The other 21 patients received 0.25 mg of cetrorelix daily when the leading follicle reached 14 mm in diameter. Serum E(2) levels, number of growing follicles and mature oocytes, embryo quality, dose of gonadotropin used, cancellation, fertilization, implantation rate and pregnancy rate (PR). The mean serum E(2) concentration on the day of hCG administration was significantly higher in the microdose GnRH-a group than in the GnRH antagonist group (1,904 vs. 1,362 pg/mL). The clinical PRs per started cycle of microdose GnRH-a and GnRH antagonist groups were 14.2% and 9.5%, respectively. There were no statistically significant differences in the other ovulation induction characteristics, fertilization and implantation rates. Microdose GnRH-a flare-up protocol and multiple dose GnRH antagonist protocol seem to have similar efficacy in improving treatment outcomes of poor responder patients.

  19. Active control of multiple resistive wall modes

    Brunsell, P. R.; Yadikin, D.; Gregoratto, D.; Paccagnella, R.; Liu, Y. Q.; Bolzonella, T.; Cecconello, M.; Drake, J. R.; Kuldkepp, M.; Manduchi, G.; Marchiori, G.; Marrelli, L.; Partin, P.; Menmuir, S.; Ortolani, S.; Rachlew, E.; Spizzo, S.; Zanca, P.

    2005-01-01

    Active magnetic feedback suppression of resistive wall modes is of common interest for several fusion concepts relying on close conducting walls for stabilization of ideal magnetohydrodynamic (MHD) modes. In the advanced tokamak without plasma rotation the kink mode is not completely stabilized, but rather converted into an unstable resistive wall mode (RWM) with a growth time comparable to the wall magnetic flux penetration time. The reversed field pinch (RFP) is similar to the advanced tokamak in the sense that it uses a conducting wall for kink mode stabilization. Also both configurations are susceptible to resonant field error amplification of marginally stable modes. However, the RFP has a different RWM spectrum and, in general, a range of modes is unstable. Hence, the requirement for simultaneous feedback stabilization of multiple independent RWMs arises for the RFP configuration. Recent experiments on RWM feedback stabilization, performed in the RFP device EXTRAP T2R [1], are presented. The experimental results obtained are the first demonstration of simultaneous feedback control of multiple independent RWMs [2]. Using an array of active magnetic coils, a reproducible suppression of several RWMs is achieved for the duration of the discharge, 3-5 wall times, through feedback action. An array with 64 active saddle coils at 4 poloidal times 16 toroidal positions is used. The important issues of side band generation by the active coil array and the accompanying coupling of different unstable modes through the feedback action are addressed in this study. Open loop control experiments have been carried out to quantitatively study resonant field error amplification. (Author)

  20. Midtreatment flare-ups.

    Harrington, G W; Natkin, E

    1992-04-01

    It should be apparent that the prompt and effective treatment of midtreatment flare-ups of all types is an essential and integral part of the overall endodontic treatment procedure. The expeditious management of these flare-ups will do much to enhance a positive attitude among patients toward endodontic treatment and to ensure the well-being and comfort of these patients.

  1. Physics of Coupled CME and Flare Systems

    2016-12-21

    AFRL-RV-PS- AFRL-RV-PS- TR-2016-0162 TR-2016-0162 PHYSICS OF COUPLED CME AND FLARE SYSTEMS K. S. Balasubramaniam, et al. 21 December 2016 Final...30 Sep 2016 4. TITLE AND SUBTITLE Physics of Coupled CME and Flare Systems 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 61102F...objectives for this task were: (i) derive measureable physical properties and discernible structural circumstances in solar active regions that

  2. Three-Dimensional Magnetic Restructuring in Two Homologous Solar Flares in the Seismically Active NOAA AR 11283

    Liu, Chang; Deng, Na; Lee, Jeongwoo; Wiegelmann, Thomas; JIang, Chaowei; Dennis, Brian R.; Su, Yang; Donea, Alina; Wang, Haimin

    2014-01-01

    We carry out a comprehensive investigation comparing the three-dimensional magnetic field restructuring, flare energy release, and the helioseismic response of two homologous flares, the 2011 September 6 X2.1 (FL1) and September 7 X1.8 (FL2) flares in NOAA AR 11283. In our analysis, (1) a twisted flux rope (FR) collapses onto the surface at a speed of 1.5 km s(exp-1) after a partial eruption in FL1. The FR then gradually grows to reach a higher altitude and collapses again at 3 km s(exp-1) after a fuller eruption in FL2. Also, FL2 shows a larger decrease of the flux-weighted centroid separation of opposite magnetic polarities and a greater change of the horizontal field on the surface. These imply a more violent coronal implosion with corresponding more intense surface signatures in FL2. (2) The FR is inclined northward and together with the ambient fields, it undergoes a southward turning after both events. This agrees with the asymmetric decay of the penumbra observed in the peripheral regions. (3) The amounts of free magnetic energy and nonthermal electron energy released during FL1 are comparable to those of FL2 within the uncertainties of the measurements. (4) No sunquake was detected in FL1; in contrast, FL2 produced two seismic emission sources S1 and S2 both lying in the penumbral regions. Interestingly, S1 and S2 are connected by magnetic loops, and the stronger source S2 has a weaker vertical magnetic field. We discuss these results in relation to the implosion process in the low corona and the sunquake generation.

  3. Three-dimensional magnetic restructuring in two homologous solar flares in the seismically active NOAA AR 11283

    Liu, Chang; Deng, Na; Lee, Jeongwoo; Wang, Haimin [Space Weather Research Laboratory, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States); Wiegelmann, Thomas [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig Weg 3, D-37077 Göttingen (Germany); Jiang, Chaowei [Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL 35805-1911 (United States); Dennis, Brian R. [Code 671, NASA Goddard Space Flight Center, Greenbelt, MD 20771-2400 (United States); Su, Yang [IGAM-Kanzelhöle Observatory, Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Donea, Alina, E-mail: chang.liu@njit.edu [Centre from Stellar and Planetary Astrophysics, School of Mathematical Sciences, Monash University, Melbourne, Victoria 3800 (Australia)

    2014-11-10

    We carry out a comprehensive investigation comparing the three-dimensional magnetic field restructuring, flare energy release, and the helioseismic response of two homologous flares, the 2011 September 6 X2.1 (FL1) and September 7 X1.8 (FL2) flares in NOAA AR 11283. In our analysis, (1) a twisted flux rope (FR) collapses onto the surface at a speed of 1.5 km s{sup –1} after a partial eruption in FL1. The FR then gradually grows to reach a higher altitude and collapses again at 3 km s{sup –1} after a fuller eruption in FL2. Also, FL2 shows a larger decrease of the flux-weighted centroid separation of opposite magnetic polarities and a greater change of the horizontal field on the surface. These imply a more violent coronal implosion with corresponding more intense surface signatures in FL2. (2) The FR is inclined northward and together with the ambient fields, it undergoes a southward turning after both events. This agrees with the asymmetric decay of the penumbra observed in the peripheral regions. (3) The amounts of free magnetic energy and nonthermal electron energy released during FL1 are comparable to those of FL2 within the uncertainties of the measurements. (4) No sunquake was detected in FL1; in contrast, FL2 produced two seismic emission sources S1 and S2 both lying in the penumbral regions. Interestingly, S1 and S2 are connected by magnetic loops, and the stronger source S2 has a weaker vertical magnetic field. We discuss these results in relation to the implosion process in the low corona and the sunquake generation.

  4. New Results from the Flare Genesis Experiment

    Rust, D. M.; Bernasconi, P. N.; Eaton, H. A.; Keller, C.; Murphy, G. A.; Schmieder, B.

    2000-05-01

    From January 10 to 27, 2000, the Flare Genesis solar telescope observed the Sun while suspended from a balloon in the stratosphere above Antarctica. The goal of the mission was to acquire long time series of high-resolution images and vector magnetograms of the solar photosphere and chromosphere. Images were obtained in the magnetically sensitive Ca I line at 6122 Angstroms and at H-alpha (6563 Angstroms). The FGE data were obtained in the context of Max Millennium Observing Campaign #004, the objective of which was to study the ``Genesis of Solar Flares and Active Filaments/Sigmoids." Flare Genesis obtained about 26,000 usable images on the 8 targeted active regions. A preliminary examination reveals a good sequence on an emerging flux region and data on the M1 flare on January 22, as well as a number of sequences on active filaments. We will present the results of our first analysis efforts. Flare Genesis was supported by NASA grants NAG5-4955, NAG5-5139, and NAG5-8331 and by NSF grant OPP-9615073. The Air Force Office of Scientific Research and the Ballistic Missile Defense Organization supported early development of the Flare Genesis Experiment.

  5. A Tool for Empirical Forecasting of Major Flares, Coronal Mass Ejections, and Solar Particle Events from a Proxy of Active-Region Free Magnetic Energy

    Barghouty, A. F.; Falconer, D. A.; Adams, J. H., Jr.

    2010-01-01

    This presentation describes a new forecasting tool developed for and is currently being tested by NASA s Space Radiation Analysis Group (SRAG) at JSC, which is responsible for the monitoring and forecasting of radiation exposure levels of astronauts. The new software tool is designed for the empirical forecasting of M and X-class flares, coronal mass ejections, as well as solar energetic particle events. Its algorithm is based on an empirical relationship between the various types of events rates and a proxy of the active region s free magnetic energy, determined from a data set of approx.40,000 active-region magnetograms from approx.1,300 active regions observed by SOHO/MDI that have known histories of flare, coronal mass ejection, and solar energetic particle event production. The new tool automatically extracts each strong-field magnetic areas from an MDI full-disk magnetogram, identifies each as an NOAA active region, and measures a proxy of the active region s free magnetic energy from the extracted magnetogram. For each active region, the empirical relationship is then used to convert the free magnetic energy proxy into an expected event rate. The expected event rate in turn can be readily converted into the probability that the active region will produce such an event in a given forward time window. Descriptions of the datasets, algorithm, and software in addition to sample applications and a validation test are presented. Further development and transition of the new tool in anticipation of SDO/HMI is briefly discussed.

  6. Activation of Necroptosis in Multiple Sclerosis

    Dimitry Ofengeim

    2015-03-01

    Full Text Available Multiple sclerosis (MS, a common neurodegenerative disease of the CNS, is characterized by the loss of oligodendrocytes and demyelination. Tumor necrosis factor α (TNF-α, a proinflammatory cytokine implicated in MS, can activate necroptosis, a necrotic cell death pathway regulated by RIPK1 and RIPK3 under caspase-8-deficient conditions. Here, we demonstrate defective caspase-8 activation, as well as activation of RIPK1, RIPK3, and MLKL, the hallmark mediators of necroptosis, in the cortical lesions of human MS pathological samples. Furthermore, we show that MS pathological samples are characterized by an increased insoluble proteome in common with other neurodegenerative diseases such as Alzheimer’s disease (AD, Parkinson’s disease (PD, and Huntington’s disease (HD. Finally, we show that necroptosis mediates oligodendrocyte degeneration induced by TNF-α and that inhibition of RIPK1 protects against oligodendrocyte cell death in two animal models of MS and in culture. Our findings demonstrate that necroptosis is involved in MS and suggest that targeting RIPK1 may represent a therapeutic strategy for MS.

  7. The role of MEXART in the National Space Weather Laboratory of Mexico: Detection of solar wind, CMEs, ionosphere, active regions and flares.

    Mejia-Ambriz, J.; Gonzalez-Esparza, A.; De la Luz, V.; Villanueva-Hernandez, P.; Andrade, E.; Aguilar-Rodriguez, E.; Chang, O.; Romero Hernandez, E.; Sergeeva, M. A.; Perez Alanis, C. A.; Reyes-Marin, P. A.

    2017-12-01

    The National Space Weather Laboratory - Laboratorio Nacional de Clima Espacial (LANCE) - of Mexico has different ground based instruments to study and monitor the space weather. One of these instruments is the Mexican Array Radio Telescope (MEXART) which is principally dedicated to remote sensing the solar wind and coronal mass ejections (CMEs) at 140 MHz, the instrument can detect solar wind densities and speeds from about 0.4 to 1 AU by modeling observations of interplanetary scintillation (IPS). MEXART is also able to detect ionospheric disturbances associated with transient space weather events by the analysis of ionospheric scintillation (IONS) . Additionally, MEXART has followed the Sun since the beginning of the current Solar Cycle 24 with records of 8 minutes per day, and occasionally, has partially detected the process of strong solar flares. Here we show the contributions of MEXART to the LANCE by reporting recent detections of CMEs by IPS, the arrive of transient events at Earth by IONS, the influence of active regions in the flux of the Sun at 140 MHz and the detection of a M6.5 class flare. Furthermore we report the status of a near real time analysis of IPS data for forecast purposes and the potential contribution to the Worldwide IPS Stations network (WIPSS), which is an effort to achieve a better coverage of the solar wind observations in the inner heliosphere.

  8. Flare stars in Pleiades. 5

    Mirzoyan, L.V.; Chavushyan, O.S.; Erastova, L.K.; Oganyan, G.B.; Melikyan, N.D.; Natsvlishvili, R.Sh.; Tsvetkov, M.K.

    1977-01-01

    The results of photographic observations of stellar flares in the Pleiades region made in the Byurakan and Abastumany astrophysical observatories in 1973-1974 are presented. The observations and revisions of the pictures taken earlier helped to detect 20 new flare stars and 62 repeated flares of flare stars known before. Two-colour photographic and UV observation of 21 flares were carried out. The observation data point to considerable differences in the mean frequency of flares of various flare stars in the Pleiades

  9. Technical and economic analysis use of flare gas into alternative energy as a breakthrough in achieving zero routine flaring

    Petri, Y.; Juliza, H.; Humala, N.

    2018-03-01

    The activity of exploring natural oil and gas will produce gas flare 0.584 MMSCFD. A gas flare is the combustion of gas remaining to avoid poisonous gas like H2S and CO which is very dangerous for human and environmental health. The combustion can bring about environmental pollution and losses because it still contains valuable energy. It needs the policy to encourage the use of flare gas with Zero Routine Flaring and green productivity to reduce waste and pollution. The objective of the research was to determine the use of gas flare so that it will have economic value and can achieve Zero Routine Flaring. It was started by analysing based on volume or rate and composition gas flare was used to determine technical feasibility, and the estimation of the gas reserves as the determination of the economy of a gas well. The results showed that the use of flare gas as fuel for power generation feasible to be implemented technically and economically with Internal Rate of Return (IRR) 19.32% and the Payback Period (PP) 5 year. Thus, it can increase gas flare value economically and can achieve a breakthrough in Zero Routine Flaring.

  10. Modelling emissions from natural gas flaring

    G. Ezaina Umukoro

    2017-04-01

    Full Text Available The world today recognizes the significance of environmental sustainability to the development of nations. Hence, the role oil and gas industry plays in environmental degrading activities such as gas flaring is of global concern. This study presents material balance equations and predicts results for non-hydrocarbon emissions such as CO2, CO, NO, NO2, and SO2 etc. from flaring (combustion of 12 natural gas samples representing composition of natural gas of global origin. Gaseous emission estimates and pattern were modelled by coding material balance equations for six reaction types and combustion conditions with a computer program. On the average, anticipated gaseous emissions from flaring natural gas with an average annual global flaring rate 126 bcm per year (between 2000 and 2011 in million metric tonnes (mmt are 560 mmt, 48 mmt, 91 mmt, 93 mmt and 50 mmt for CO2, CO, NO, NO2 and SO2 respectively. This model predicted gaseous emissions based on the possible individual combustion types and conditions anticipated in gas flaring operation. It will assist in the effort by environmental agencies and all concerned to track and measure the extent of environmental pollution caused by gas flaring operations in the oil and gas industry.

  11. Lyman continuum observations of solar flares

    Machado, M. E.; Noyes, R. W.

    1978-01-01

    A study is made of Lyman continuum observations of solar flares, using data obtained by the EUV spectroheliometer on the Apollo Telescope Mount. It is found that there are two main types of flare regions: an overall 'mean' flare coincident with the H-alpha flare region, and transient Lyman continuum kernels which can be identified with the H-alpha and X-ray kernels observed by other authors. It is found that the ground level hydrogen population in flares is closer to LTE than in the quiet sun and active regions, and that the level of Lyman continuum formation is lowered in the atmosphere from a mass column density .000005 g/sq cm in the quiet sun to .0003 g/sq cm in the mean flare, and to .001 g/sq cm in kernels. From these results the amount of chromospheric material 'evaporated' into the high temperature region is derived, which is found to be approximately 10 to the 15th g, in agreement with observations of X-ray emission measures.

  12. Solar Features - Solar Flares

    National Oceanic and Atmospheric Administration, Department of Commerce — A solar flare is a short-lived sudden increase in the intensity of radiation emitted in the neighborhood of sunspots. For many years it was best monitored in the...

  13. Proton solar flares

    Shaposhnikova, E.F.

    1979-01-01

    The observations of proton solar flares have been carried out in 1950-1958 using the extrablackout coronograph of the Crimea astrophysical observatory. The experiments permit to determine two characteristic features of flares: the directed motion of plasma injection flux from the solar depths and the appearance of a shock wave moving from the place of the injection along the solar surface. The appearance of the shock wave is accompanied by some phenomena occuring both in the sunspot zone and out of it. The consistent flash of proton flares in the other groups of spots, the disappearance of fibres and the appearance of eruptive prominences is accomplished in the sunspot zone. Beyond the sunspot zone the flares occur above spots, the fibres disintegrate partially or completely and the eruptive prominences appear in the regions close to the pole

  14. Multiple-Active Multiple-Passive Antenna Systems and Applications

    Tsakalaki, Elpiniki

    2013-01-01

    -passive (MAMP) antenna topologies, as explained in Sect. 8.1. Then, Sect. 8.2 proposes MAMP antenna structures with application to reconfigurable MIMO transmission in the presence of antenna mutual coupling under poor scattering channel conditions. For this purpose, the section presents an adaptive MAMP antenna...... system capable of changing its transmission parameters via passive radiators attached to tunable loads, according to the structure of the RF propagation channel. The hybrid MAMP array structure can be tractably analyzed using the active element response vector (instead of the classical steering vector...... adaptive MAMP system can be limited to practical dimensions whereas the passive antennas require no extra RF hardware, thus meeting the cost, space, and power constrains of the users’ mobile terminals. The simulation results show that the adaptive MAMP system, thanks to its “adaptivity”, is able to achieve...

  15. Improved flare tip design

    Gogolek, P. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy Technology Centre

    2004-07-01

    This paper discusses the testing procedures and development of an improved flare tip design. Design objectives included performance equal to or better than utility flares at low wind speed; conversion efficiency; fuel slip; smoking; significant improvement at high wind speed; and no increase in trace emissions. A description of the testing facility of the flare tip was provided, with reference to the fact that the facility allowed for realistic near full scale gas flares in a single-pass flare test facility. Other details of the facility included: an adjustable ceiling; high capacity variable speed fan; sampling ports along working section in stack; windows along working section; and air cooled walls, floor, and ceiling. The fuels used in the flare tip included natural gas, propane, gasoline and inert gases. Details of wind speed, appurtenances and turbulence generating grids were presented, with reference to continuous gas emission measurements. A list of design constraints was provided. Flare performance included wind speed, turbulence and fuel composition. A chart of conversion inefficiencies with a correlation of wind speed and turbulence, fuel flow and pipe size was also presented. Several new tip designs were fabricated for testing, with screening tests for comparison to basic pipe and ranking designs. Significant improvements were found in one of the new designs, including results with 30 per cent propane in fuel. Emissions reduction from 10 to 35 per cent were noted. It was concluded that future work should focus on evaluating improved tip for stability at low wind speeds. Fuel slips are the primary source of emissions, and it was recommended that further research is necessary to improve existing flare tips. tabs, figs.

  16. Do Long-cadence Data of the Kepler Spacecraft Capture Basic Properties of Flares?

    Yang, Huiqin; Liu, Jifeng; Qiao, Erlin; Zhang, Haotong; Gao, Qing; Cui, Kaiming; Han, Henggeng

    2018-06-01

    Flare research is becoming a burgeoning realm of interest in the study of stellar activity due to the launch of Kepler in 2009. Kepler provides data with two time resolutions, i.e., the long-cadence (LC) data with a time resolution of 30 minutes and the short-cadence (SC) data with a time resolution of 1 minute, both of which can be used to study stellar flares. In this paper, we search flares in light curves with both LC data and SC data, and compare them in aspects of the true-flare rate, the flare energy, the flare amplitude, and the flare duration. It is found that LC data systematically underestimated the energies of flares by 25%, and underestimated the amplitudes of flares by 60% compared with SC flares. The durations are systematically overestimated by 50% compared with SC flares. However, the above percentages are poorly constrained and there is a lot of scatter. About 60% of SC flares have not been detected by LC data. We investigate the limitation of LC data, and suggest that although LC data cannot reflect the detailed profiles of flares, they can also capture the basic properties of stellar flares.

  17. The Miniature X-ray Solar Spectrometer (MinXSS) CubeSats: instrument capabilities and early science analysis on the quiet Sun, active regions, and flares.

    Moore, Christopher S.; Woods, Tom; Caspi, Amir; Dennis, Brian R.; MinXSS Instrument Team, NIST-SURF Measurement Team

    2018-01-01

    Detection of soft X-rays (sxr) from the Sun provide direct information on coronal plasma at temperatures in excess of ~1 MK, but there have been relatively few solar spectrally resolved measurements from 0.5 – 10. keV. The Miniature X-ray Solar Spectrometer (MinXSS) CubeSat is the first solar science oriented CubeSat mission flown for the NASA Science Mission Directorate, and has provided measurements from 0.8 -12 keV, with resolving power ~40 at 5.9 keV, at a nominal ~10 second time cadence. MinXSS design and development has involved over 40 graduate students supervised by professors and professionals at the University of Colorado at Boulder. Instrument radiometric calibration was performed at the National Institute for Standard and Technology (NIST) Synchrotron Ultraviolet Radiation Facility (SURF) and spectral resolution determined from radioactive X-ray sources. The MinXSS spectra allow for determining coronal abundance variations for Fe, Mg, Ni, Ca, Si, S, and Ar in active regions and during flares. Measurements from the first of the twin CubeSats, MinXSS-1, have proven to be consistent with the Geostationary Operational Environmental Satellite (GOES) 0.1 – 0.8 nm energy flux. Simultaneous MinXSS-1 and Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observations have provided the most complete sxr spectral coverage of flares in recent years. These combined measurements are vital in estimating the heating flare loops by non-thermal accelerated electrons. MinXSS-1 measurements have been combined with the Hinode X-ray Telescope (XRT) and Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO-AIA) to further constrain the coronal temperature distribution during quiescent times. The structure of the temperature distribution (especially for T > 5 MK) is important for deducing heating processes in the solar atmosphere. MinXSS-1 observations yield some of the tightest constraints on the high temperature component of the coronal plasma, in the

  18. Identifying flares in rheumatoid arthritis

    Bykerk, Vivian P; Bingham, Clifton O; Choy, Ernest H

    2016-01-01

    to flare, with escalation planned in 61%. CONCLUSIONS: Flares are common in rheumatoid arthritis (RA) and are often preceded by treatment reductions. Patient/MD/DAS agreement of flare status is highest in patients worsening from R/LDA. OMERACT RA flare questions can discriminate between patients with...... Set. METHODS: Candidate flare questions and legacy measures were administered at consecutive visits to Canadian Early Arthritis Cohort (CATCH) patients between November 2011 and November 2014. The American College of Rheumatology (ACR) core set indicators were recorded. Concordance to identify flares...

  19. Flaring red dwarf stars: news from Crimea

    Gershberg, Roald E

    1998-01-01

    Important phenomena are briefly described which have recently been discovered in the Crimean studies of flaring red dwarf stars believed to be the most common type of variable stars in the Galaxy. These phenomena include (i) long-lived radiation from a blueshifted component in the ionized-helium λ 4686 A emission line in the active state of one such star, (ii) a long-lived absorption component in the stellar flare light curves with a lifetime exceeding that of the conventional flare emission, and (iii) solarcycle-like activity periodicity of the star EV Lac, whose mass is only 0.3 solar masses. In theoretical terms, a red dwarf star spot model is constructed which, in contrast to the commonly accepted model, agrees well with the solar spot picture. (physics of our days)

  20. Flaring red dwarf stars: news from Crimea

    Gershberg, Roald E [Crimean Astrophysical Observatory, Nauchnyi, Crimea (Ukraine)

    1998-08-31

    Important phenomena are briefly described which have recently been discovered in the Crimean studies of flaring red dwarf stars believed to be the most common type of variable stars in the Galaxy. These phenomena include (i) long-lived radiation from a blueshifted component in the ionized-helium {lambda} 4686 A emission line in the active state of one such star, (ii) a long-lived absorption component in the stellar flare light curves with a lifetime exceeding that of the conventional flare emission, and (iii) solarcycle-like activity periodicity of the star EV Lac, whose mass is only 0.3 solar masses. In theoretical terms, a red dwarf star spot model is constructed which, in contrast to the commonly accepted model, agrees well with the solar spot picture. (physics of our days)

  1. M DWARFS IN SLOAN DIGITAL SKY SURVEY STRIPE 82: PHOTOMETRIC LIGHT CURVES AND FLARE RATE ANALYSIS

    Kowalski, Adam F.; Hawley, Suzanne L.; Hilton, Eric J.; Becker, Andrew C.; Sesar, Branimir; West, Andrew A.; Bochanski, John J.

    2009-01-01

    We present a flare rate analysis of 50,130 M dwarf light curves in Sloan Digital Sky Survey Stripe 82. We identified 271 flares using a customized variability index to search ∼2.5 million photometric observations for flux increases in the u and g bands. Every image of a flaring observation was examined by eye and with a point-spread function-matching and image subtraction tool to guard against false positives. Flaring is found to be strongly correlated with the appearance of Hα in emission in the quiet spectrum. Of the 99 flare stars that have spectra, we classify eight as relatively inactive. The flaring fraction is found to increase strongly in stars with redder colors during quiescence, which can be attributed to the increasing flare visibility and increasing active fraction for redder stars. The flaring fraction is strongly correlated with |Z| distance such that most stars that flare are within 300 pc of the Galactic plane. We derive flare u-band luminosities and find that the most luminous flares occur on the earlier-type m dwarfs. Our best estimate of the lower limit on the flaring rate (averaged over Stripe 82) for flares with Δu ≥ 0.7 mag on stars with u -1 deg -2 but can vary significantly with the line of sight.

  2. Flare stars in Pleiades. 6

    Mirzoyan, L.V.; Chavushyan, O.S.; Oganyan, G.B.; Ambaryan, V.V.; Garibdzhanyan, A.T.; Melikyan, N.D.; Natsvlishvili, R.Sh.; AN Gruzinskoj SSR, Abastumani. Abastumanskaya Astrofizicheskaya Observatoriya)

    1981-01-01

    The results of photographic observations of stellar flares in the Pleiades region carried out at the Byurakan and Abastumani astrophysical observatories during 1976-1979 are given. On the basis of these observations 17 new flare stars have been found. Total number of all known flare stars in the Pleiades region on 1 June 1980 reached 524, and the number of all flares-1244. The observational data on distribution of flare stars according to the observed flares is satisfactorily represented by the average frequency function introduced by V.A.Ambartsumian. The total number of the flare stars in the Pleiades is of the order of 1100. Using three telescopes, synchronous photographic observations of stellar flares in Pleiades in U, B, V, system are carried out. The colour indices U-B and B-V of stellar flares in periods including the maximum of the flare slightly differ from that of photoelectrically defined for flares of UV Ceti type stars, which testifies the physical relationship of flare stars in Pleiades and in the vicinity of the Sun [ru

  3. Some evidence on the evolution of the flare mechanism in dwarf stars

    Skumanich, A.

    1986-10-01

    White-light flare parameters are estimated for the sun as a star. It is found that these parameters fall in the same domain as those for the dMe flare stars. In particular, it is found that the time-averaged flare power loss and quiescent coronal soft X-ray power loss at solar maximum satisfies the recently proposed flare power-coronal X-ray relation for dMe stars (Doyle and Butler; Skumanich). In addition, one finds that dM stars, which are believed to be magnetically evolved dMe stars, also satisfy the same relation. On this basis, an evolutionary scenario is suggested for the flare mechanism in which the total flare rate remains, more or less, constant but the mean flare yield decreases linearly with coronal X-ray strength. It is also suggested that the flare mechanism is universal in all magnetically active dwarfs. 48 references.

  4. USING CLOSE WHITE DWARF + M DWARF STELLAR PAIRS TO CONSTRAIN THE FLARE RATES IN CLOSE STELLAR BINARIES

    Morgan, Dylan P.; West, Andrew A. [Astronomy Department, Boston University, 725 Commonwealth Ave, Boston, MA 02215 (United States); Becker, Andrew C., E-mail: dpmorg@bu.edu [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)

    2016-05-01

    We present a study of the statistical flare rates of M dwarfs (dMs) with close white dwarf (WD) companions (WD+dM; typical separations <1 au). Our previous analysis demonstrated that dMs with close WD companions are more magnetically active than their field counterparts. One likely implication of having a close binary companion is increased stellar rotation through disk-disruption, tidal effects, and/or angular momentum exchange; increased stellar rotation has long been associated with an increase in stellar activity. Previous studies show a strong correlation between dMs that are magnetically active (showing H α in emission) and the frequency of stellar flare rates. We examine the difference between the flare rates observed in close WD+dM binary systems and field dMs. Our sample consists of a subset of 181 close WD+dM pairs from Morgan et al. observed in the Sloan Digital Sky Survey Stripe 82, where we obtain multi-epoch observations in the Sloan ugriz -bands. We find an increase in the overall flaring fraction in the close WD+dM pairs (0.09 ± 0.03%) compared to the field dMs (0.0108 ± 0.0007%) and a lower flaring fraction for active WD+dMs (0.05 ± 0.03%) compared to active dMs (0.28 ± 0.05%). We discuss how our results constrain both the single and binary dM flare rates. Our results also constrain dM multiplicity, our knowledge of the Galactic transient background, and may be important for the habitability of attending planets around dMs with close companions.

  5. Exergy analysis of waste emissions from gas flaring

    Olawale Saheed ISMAIL

    2016-07-01

    Full Text Available Gas flaring produces a stream of waste gases at high temperature and pressure which contains carbon monoxide, Hydrogen Sulphide etc. The resultant effect of which is detrimental to our planet and, consequently, to the life of both the living and the non-living things. It’s well known that gas flaring contributes in no small measure to the global warming. Exergy analysis is applied in this work to analyze waste emissions from gas flaring so as to have a model through which impact of gas flaring can be measured. The study considers both the thermo-mechanical exergy and the chemical exergy of these gases. Relevant data on gas flaring activities in the Niger-Delta region of Nigeria between the periods of fifteen (15 years was obtained from the Nigerian National Petroleum Corporation (NNPC. A computer program (Exergy Calculator was developed based on the equations generated in the Model. Exergy associated with gas flaring activities in Nigeria between the periods of 1998 through 2012 was calculated. The results show that 1 mscf (in thousand cubic feet of flared gases generate 0.000041 MWh of energy leading to a value of 440158.607 MWh of energy for the period under review.The analysis provides important conclusions and recommendations for improving oil platforms operationsin in order to safeguard the environment, health of the populace, and maximize recovered exergy from gas flaring.

  6. Constraining the location of rapid gamma-ray flares in the flat spectrum radio quasar 3C 273 [Constraining the location of rapid gamma-ray flares in the FSRQ 3C 273

    Rani, B.; Lott, B.; Krichbaum, T. P.; Fuhrmann, L.; Zensus, J. A.

    2013-01-01

    Here, we present a γ-ray photon flux and spectral variability study of the flat-spectrum radio quasar 3C 273 over a rapid flaring activity period between September 2009 to April 2010. Five major flares were observed in the source during this period. The most rapid flare observed in the source has a flux doubling time of 1.1 hr. The rapid γ-ray flares allow us to constrain the location and size of the γ-ray emission region in the source. The γγ-opacity constrains the Doppler factor δ_γ ≥ 10 for the highest energy (15 GeV) photon observed by the Fermi-Large Area Telescope (LAT). Causality arguments constrain the size of the emission region to 1.6 × 10"1"5 cm. The γ-ray spectra measured over this period show clear deviations from a simple power law with a break in the 1–2 GeV energy range. We discuss possible explanations for the origin of the γ-ray spectral breaks. Our study suggests that the γ-ray emission region in 3C 273 is located within the broad line region (< 1.6 pc). As a result, the spectral behavior and temporal characteristics of the individual flares indicate the presence of multiple shock scenarios at the base of the jet.

  7. Glycoside hydrolases having multiple hydrolase activities

    Chen, Zhiwei; Friedland, Gregory D.; Chhabra, Swapnil R.; Chivian, Dylan C.; Simmons, Blake A

    2017-08-08

    Glycoside hydrolases having at least two different hydrolytic activities are provided. In one embodiment, an isolated recombinant hydrolase having at least two activities selected from a group including asparagine derivatives, glutamine derivatives, and histidine derivatives is provided. Further, a method of generating free sugars from a mixture comprising asparagine derivatives, glutamine derivatives, and histidine derivatives is provided.

  8. M DWARF FLARES FROM TIME-RESOLVED SLOAN DIGITAL SKY SURVEY SPECTRA

    Hilton, Eric J.; Hawley, Suzanne L.; Kowalski, Adam F.; West, Andrew A.

    2010-01-01

    We have identified 63 flares on M dwarfs from the individual component spectra in the Sloan Digital Sky Survey (SDSS) using a novel measurement of emission-line strength called the Flare Line Index. Each of the ∼38,000 M dwarfs in the SDSS low-mass star spectroscopic sample of West et al. was observed several times (usually 3-5) in exposures that were typically 9-25 minutes in duration. Our criteria allowed us to identify flares that exhibit very strong Hα and Hβ emission-line strength and/or significant variability in those lines throughout the course of the exposures. The flares we identified have characteristics consistent with flares observed by classical spectroscopic monitoring. The flare duty cycle for the objects in our sample is found to increase from 0.02% for early M dwarfs to 3% for late M dwarfs. We find that the flare duty cycle is larger in the population near the Galactic plane and that the flare stars are more spatially restricted than the magnetically active but non-flaring stars. This suggests that flare frequency may be related to stellar age (younger stars are more likely to flare) and that the flare stars are younger than the mean active population.

  9. Future flare compositions

    Lingen, J.L.N. van; Meuken, D.; Hackspik, M.M.; Mäkeläinen, T.; Weiser, V.; Poulson, G.W.

    2014-01-01

    This poster describes the work done within the Category B joint research project under the European Defence Agency (EDA) on Future Flare Compositions [1]. Contributing members were Finland, Germany, United Kingdom and the Netherlands. The program was aimed to identify the technology gaps that apply

  10. Flaring research update

    Reynen, B.A.

    1999-01-01

    Several studies regarding waste gas flaring have been conducted in an effort to determine the potential health and environmental impacts associated with flaring. Energy source conservation and greenhouse gas emissions reduction are other reasons for studying the issue. A brief outline for each of the following research priorities was given: (1) operating practices, (2) flare performance, focusing on improved combustion efficiency, (3) speciation, addressing the potential effects of incomplete combustion, (4) alternative technologies such as membrane technology, cryogenics and power generation to reduce flare gas volume, (5) improved liquid separation, concentrating on the removal of entrained liquids to improve performance and reduce emissions and (6) fate and transport, including plume modeling, ambient air monitoring, tracking of known toxins, primarily to address concerns of environmental groups.The expectation is that this broad and comprehensive research effort will yield substantive and credible scientific data, lead to cooperation in the research community, reduce emissions, beneficially impact on regulations and standards and gain the support of environmental organizations

  11. Establishing a core domain set to measure rheumatoid arthritis flares

    Bykerk, Vivian P; Lie, Elisabeth; Bartlett, Susan J

    2014-01-01

    OBJECTIVE: The OMERACT Rheumatoid Arthritis (RA) Flare Group (FG) is developing a data-driven, patient-inclusive, consensus-based RA flare definition for use in clinical trials, longterm observational studies, and clinical practice. At OMERACT 11, we sought endorsement of a proposed core domain set...... to measure RA flare. METHODS: Patient and healthcare professional (HCP) qualitative studies, focus groups, and literature review, followed by patient and HCP Delphi exercises including combined Delphi consensus at Outcome Measures in Rheumatology 10 (OMERACT 10), identified potential domains to measure flare...... Filter 2.0 methodology. RESULTS: A pre-meeting combined Delphi exercise for defining flare identified 9 domains as important (>70% consensus from patients or HCP). Four new patient-reported domains beyond those included in the RA disease activity core set were proposed for inclusion (fatigue...

  12. Quasi-periodic Pulsations in the Most Powerful Solar Flare of Cycle 24

    Kolotkov, Dmitrii Y.; Pugh, Chloe E.; Broomhall, Anne-Marie; Nakariakov, Valery M.

    2018-05-01

    Quasi-periodic pulsations (QPPs) are common in solar flares and are now regularly observed in stellar flares. We present the detection of two different types of QPP signals in the thermal emission light curves of the X9.3-class solar flare SOL2017-09-06T12:02, which is the most powerful flare of Cycle 24. The period of the shorter-period QPP drifts from about 12 to 25 s during the flare. The observed properties of this QPP are consistent with a sausage oscillation of a plasma loop in the flaring active region. The period of the longer-period QPP is about 4 to 5 minutes. Its properties are compatible with standing slow magnetoacoustic oscillations, which are often detected in coronal loops. For both QPP signals, other mechanisms such as repetitive reconnection cannot be ruled out, however. The studied solar flare has an energy in the realm of observed stellar flares, and the fact that there is evidence of a short-period QPP signal typical of solar flares along with a long-period QPP signal more typical of stellar flares suggests that the different ranges of QPP periods typically observed in solar and stellar flares is likely due to observational constraints, and that similar physical processes may be occurring in solar and stellar flares.

  13. THE FLARE-ONA OF EK DRACONIS

    Ayres, Thomas R.

    2015-01-01

    EK Draconis (HD 129333: G1.5 V) is a well-known young (50 Myr) solar analog. In 2012, Hubble Space Telescope returned to EK Dra to follow up a far-ultraviolet (FUV) SNAPshot visit by Cosmic Origins Spectrograph (COS) two years earlier. The brief SNAP pointing had found surprisingly redshifted, impulsively variable subcoronal “hot-line” emission of Si iv 1400 Å (T ∼ 8 × 10 4 K). Serendipitously, the 2012 follow-on program witnessed one of the largest FUV flares ever recorded on a sunlike star, which again displayed strong redshifts (downflows) of 30–40 km s −1 , even after compensating for small systematics in the COS velocity scales, uncovered through a cross-calibration by Space Telescope Imaging Spectrograph (STIS). The (now reduced, but still substantial) ∼10 km s −1 hot-line redshifts outside the flaring interval did not vary with rotational phase, so cannot be caused by “Doppler imaging” (bright surface patches near a receding limb). Density diagnostic O iv] 1400 Å multiplet line ratios of EK Dra suggest n e ∼ 10 11 cm −3 , an order of magnitude larger than in low-activity solar twin α Centauri A, but typical of densities inferred in large stellar soft X-ray events. The self-similar FUV hot-line profiles between the flare decay and the subsequent more quiet periods, and the unchanging but high densities, reinforce a long-standing idea that the coronae of hyperactive dwarfs are flaring all the time, in a scale-free way; a flare-ona if you will. In this picture, the subsonic hot-line downflows probably are a byproduct of the post-flare cooling process, something like “coronal rain” on the Sun. All in all, the new STIS/COS program documents a complex, energetic, dynamic outer atmosphere of the young sunlike star

  14. Frequent Flaring in the TRAPPIST-1 System—Unsuited for Life?

    Vida, K.; Kővári, Zs.; Pál, A.; Oláh, K.; Kriskovics, L., E-mail: vidakris@konkoly.hu [Konkoly Observatory, MTA CSFK, H-1121 Budapest, Konkoly Thege M. út 15-17 (Hungary)

    2017-06-01

    We analyze the K2 light curve of the TRAPPIST-1 system. The Fourier analysis of the data suggests P {sub rot} = 3.295 ± 0.003 days. The light curve shows several flares, of which we analyzed 42 events with integrated flare energies of 1.26 × 10{sup 30}–1.24 × 10{sup 33} erg. Approximately 12% of the flares were complex, multi-peaked eruptions. The flaring and the possible rotational modulation shows no obvious correlation. The flaring activity of TRAPPIST-1 probably continuously alters the atmospheres of the orbiting exoplanets, which makes these less favorable for hosting life.

  15. Feasibility and Domain Validation of Rheumatoid Arthritis (RA) Flare Core Domain Set

    Bartlett, Susan J; Bykerk, Vivian P; Cooksey, Roxanne

    2015-01-01

    , and stiffness scores averaged ≥ 2 times higher (2 of 11 points) in flaring individuals. Correlations between flare domains and corresponding legacy instruments were obtained: r = 0.46 to 0.93. A combined definition (patient report of flare and 28-joint Disease Activity Score increase) was evaluated in 2 other...... provided input for stiffness, self-management, contextual factors, and measurement considerations. RESULTS: Flare data from 501 patients in an observational study indicated 39% were in flare, with mean (SD) severity of 6.0 (2.6) and 55% lasting > 14 days. Pain, physical function, fatigue, participation...

  16. Active neutron multiplicity analysis and Monte Carlo calculations

    Krick, M.S.; Ensslin, N.; Langner, D.G.; Miller, M.C.; Siebelist, R.; Stewart, J.E.; Ceo, R.N.; May, P.K.; Collins, L.L. Jr

    1994-01-01

    Active neutron multiplicity measurements of high-enrichment uranium metal and oxide samples have been made at Los Alamos and Y-12. The data from the measurements of standards at Los Alamos were analyzed to obtain values for neutron multiplication and source-sample coupling. These results are compared to equivalent results obtained from Monte Carlo calculations. An approximate relationship between coupling and multiplication is derived and used to correct doubles rates for multiplication and coupling. The utility of singles counting for uranium samples is also examined

  17. Developing a Construct to Evaluate Flares in Rheumatoid Arthritis: A Conceptual Report of the OMERACT RA Flare Definition Working Group

    Alten, Rieke; Choy, Ernest H; Christensen, Robin

    2011-01-01

    Rheumatoid arthritis (RA) patients and healthcare professionals (HCP) recognize that episodic worsening disease activity, often described as a "flare," is a common feature of RA that can contribute to impaired function and disability. However, there is no standard definition to enable measurement...... of its intensity and impact. The conceptual framework of the Outcome Measures in Rheumatology Clinical Trials (OMERACT) RA Flare Definition Working Group includes an anchoring statement, developed at OMERACT 9 in 2008: "flare in RA" is defined as worsening of signs and symptoms of sufficient intensity....... The conceptual framework of flare takes into account validated approaches to measurement in RA: (1) various disease activity indices (e.g., Disease Activity Score, Clinical Disease Activity Index, Simplified Disease Activity Index); (2) use of patient-reported outcomes (PRO); and (3) characterization...

  18. Chromosphere flare models

    Avrett, E.H.; Kurucz, R.L.; Machado, M.E.; NASA, Marshall Space Flight Center, Huntsville, AL)

    1985-01-01

    Further calculated results based on the F1 and F2 chromospheric models of Machado et al. (1980) are presented in addition to results from a model with enhanced temperatures relative to the weak-flare model F1 in the upper photosphere and low chromosphere, and from a model with enhanced temperatures relative to the strong flare model F2 in the upper chromosphere. The coupled equations of statistical equilibrium and radiative transfer for H, H(-), He I-II, C I-IV, Si I-II, Mg I-II, Fe, Al, O I-II, Na, and Ca II are solved, and the overall absorption and emission of radiation by lines throughout the spectrum are determined by means of a reduced set of opacities taken from a compilation of over 10 million lines. Semiempirical models show that the white light flare continuum may arise by extreme chromospheric overheating, as well as by an enhancement of the minimum temperature region. 34 references

  19. Flares on a Bp Star

    Mullan, D. J.

    2009-09-01

    Two large X-ray flares have been reported from the direction of a magnetic B2p star (σ Ori E). Sanz-Forcada et al. have suggested that the flares did not occur on the B2p star but on a companion of late spectral type. A star which is a candidate for a late-type flare star near σ Ori E has recently been identified by Bouy et al. However, based on the properties of the flares, and based on a recent model of rotating magnetospheres, we argue that, rather than attributing the two flares to a late-type dwarf, it is a viable hypothesis that the flares were magnetic phenomena associated with the rotating magnetosphere of the B2p star itself.

  20. FLARES ON A Bp STAR

    Mullan, D. J.

    2009-01-01

    Two large X-ray flares have been reported from the direction of a magnetic B2p star (σ Ori E). Sanz-Forcada et al. have suggested that the flares did not occur on the B2p star but on a companion of late spectral type. A star which is a candidate for a late-type flare star near σ Ori E has recently been identified by Bouy et al. However, based on the properties of the flares, and based on a recent model of rotating magnetospheres, we argue that, rather than attributing the two flares to a late-type dwarf, it is a viable hypothesis that the flares were magnetic phenomena associated with the rotating magnetosphere of the B2p star itself.

  1. Physical activity motivation and benefits in people with multiple sclerosis.

    Fasczewski, Kimberly S; Gill, Diane L; Rothberger, Sara M

    2018-06-01

    Multiple sclerosis is a degenerative neurological disease that affects 2.1 million people worldwide. There is no cure, but an expanding body of research supports the positive impact of physical activity and suggests physical activity has benefits for the individual's psychological and physical well-being. Using Self-Determination Theory as a framework, mixed methods with a focus on qualitative interviews were used to explore physical activity motivation and benefits with a sample of highly active people with multiple sclerosis (n = 15). Disability level ranged from not disabled to wheelchair bound with the majority of participants reporting minimal impact from multiple sclerosis. Survey data were collected using a number of open-ended questions along with measures of self-efficacy, self-determined motivation, physical activity, and quality of life. Additionally, eight individuals participated in semistructured telephone interviews focused on (a) motivation and strategies used to maintain physical activity and (b) the benefits and impact of physical activity in their lives. The main findings were consistent with Self-Determination Theory; participants described feelings of accomplishment and competence in both their physical activity and daily life, as well as a sense of independence and autonomy. Similarly, all participants cited benefits, and the main themes were enhanced satisfaction with life and an overall positive outlook on life. Results provide insight into the role of physical activity in a highly active sample and have implications for professionals working in physical activity settings with the multiple sclerosis population. Interventions aimed at increasing long-term physical activity adherence should focus on increasing autonomy and competence for physical activity in the individual and promoting potential increased quality of life outcomes from physical activity participation. Implications for Rehabilitation Multiple sclerosis is a chronic

  2. Study on Precursor Activity of the X1.6 Flare in the Great AR 12192 with SDO , IRIS , and Hinode

    Bamba, Yumi [Institute of Space and Astronautical Science (ISAS)/Japan Aerospace Exploration Agency (JAXA) 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Lee, Kyoung-Sun [National Astronomical Observatory of Japan (NAOJ) 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Imada, Shinsuke; Kusano, Kanya, E-mail: y-bamba@nagoya-u.jp [Institute for Space-Earth Environmental Research (ISEE)/Nagoya University Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan)

    2017-05-10

    The physical properties and their contribution to the onset of a solar flare are still uncleare even though chromospheric brightening is considered a precursor phenomenon of a flare. Many studies suggested that photospheric magnetic field changes cause destabilization of large-scale coronal structure. We aim to understand how a small photospheric change contributes to a flare and to reveal how the intermediary chromosphere behaves in the precursor phase. We analyzed the precursor brightening of the X1.6 flare on 2014 October 22 in the AR 12192 using the Interface Region Imaging Spectrograph ( IRIS ) and Hinode /EUV Imaging Spectrometer (EIS) data. We investigated a localized jet with the strong precursor brightening, and compared the intensity, Doppler velocity, and line width in C ii, Mg ii k, and Si iv lines by IRIS and He ii, Fe xii, and Fe xv lines by Hinode /EIS. We also analyzed the photospheric magnetic field and chromospheric/coronal structures using the Solar Dynamics Observatory ( SDO )/Helioseismic and Magnetic Imager and Atmospheric Imaging Assembly. We found a significant blueshift (∼100 km s{sup −1}), which is related to the strong precursor brightening over a characteristic magnetic field structure, and the blueshift was observed at all of the temperatures. This might indicate that the flow is accelerated by Lorentz force. Moreover, the large-scale coronal loop that connects the foot points of the flare ribbons was destabilized just after the precursor brightening with the blueshift. It suggests that magnetic reconnection locally occurred in the lower chromosphere and it triggered magnetic reconnection of the X1.6 flare in the corona.

  3. Flare-related color effects in UV Ceti stars

    Flesch, T.R.

    1975-01-01

    The UV Ceti flare stars YZ CMi, BD+16 0 2708, EV Lac, and AD Leo were monitored photoelectrically for flare activity with the 76 centimeter reflecting telescope of the University of Florida's Rosemary Hill Observatory. Observations were carried out from January, 1973 to April, 1975. The instrumentation allowed simultaneous readings to be taken at 3500, 4632, and 6496A with a time resolution of 2 seconds. A total of 15 major events were observed, with 14 of these being observed in all three colors. All events showed the classical fast rise and slower decline that is typical of this type of activity. One event showed peculiar behavior in the red bandpass that may indicate strong dependence of the flare light in some cases on line emission. The data were applied to the fast electron model of flare activity proposed by Gurzadyan. Several serious inconsistencies in the theory were found that would not have been evident in single-channel monitoring. No event could be fitted in all three colors using consistent values of the unknown parameters in the theory. The most serious deficiencies in the theory were the wavelength dependence of the optical depth of the electron cloud and the lack of treatment of line emission behavior. Differential color indices for flare light are calculated and are shown to be essentially constant throughout the entire event for the stronger flares. A color-color plot of the flare light at maximum reveals that 11 of the flares show a linear relation. This relation indicates that the smaller the u-b index, the larger is the b-r index. This is probably directly involved with line emission during flare events. Future research possibilities are discussed, with spectroscopic studies and simultaneous multicolor observations being stressed

  4. MAGNETIC AND DYNAMICAL PHOTOSPHERIC DISTURBANCES OBSERVED DURING AN M3.2 SOLAR FLARE

    Kuckein, C. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482, Potsdam (Germany); Collados, M.; Sainz, R. Manso, E-mail: ckuckein@aip.de [Instituto de Astrofísica de Canarias (IAC), Vía Láctea s/n, E-38205, La Laguna, Tenerife (Spain)

    2015-02-01

    This Letter reports on a set of full-Stokes spectropolarimetric observations in the near-infrared He i 10830 Å spectral region covering the pre-flare, flare, and post-flare phases of an M3.2 class solar flare. The flare originated on 2013 May 17 and belonged to active region NOAA 11748. We detected strong He i 10830 Å emission in the flare. The red component of the He i triplet peaks at an intensity ratio to the continuum of about 1.86. During the flare, He i Stokes V is substantially larger and appears reversed compared to the usually larger Si i Stokes V profile. The photospheric Si i inversions of the four Stokes profiles reveal the following: (1) the magnetic field strength in the photosphere decreases or is even absent during the flare phase, as compared to the pre-flare phase. However, this decrease is not permanent. After the flare, the magnetic field recovers its pre-flare configuration in a short time (i.e., 30 minutes after the flare). (2) In the photosphere, the line of sight velocities show a regular granular up- and downflow pattern before the flare erupts. During the flare, upflows (blueshifts) dominate the area where the flare is produced. Evaporation rates of ∼10{sup −3} and ∼10{sup −4} g cm{sup −2} s{sup −1} have been derived in the deep and high photosphere, respectively, capable of increasing the chromospheric density by a factor of two in about 400 s.

  5. A solar tornado triggered by flares?

    Panesar, N. K.; Innes, D. E.; Tiwari, S. K.; Low, B. C.

    2013-01-01

    Context. Solar tornados are dynamical, conspicuously helical magnetic structures that are mainly observed as a prominence activity. Aims. We investigate and propose a triggering mechanism for the solar tornado observed in a prominence cavity by SDO/AIA on September 25, 2011. Methods. High-cadence EUV images from the SDO/AIA and the Ahead spacecraft of STEREO/EUVI are used to correlate three flares in the neighbouring active-region (NOAA 11303) and their EUV waves with the dynamical de...

  6. Thermodynamic Spectrum of Solar Flares Based on SDO/EVE Observations: Techniques and First Results

    Wang, Yuming; Zhou, Zhenjun; Zhang, Jie; Liu, Kai; Liu, Rui; Shen, Chenglong; Chamberlin, Phillip C.

    2016-01-01

    The Solar Dynamics Observatory (SDO)/EUV Variability Experiment (EVE) provides rich information on the thermodynamic processes of solar activities, particularly on solar flares. Here, we develop a method to construct thermodynamic spectrum (TDS) charts based on the EVE spectral lines. This tool could potentially be useful for extreme ultraviolet (EUV) astronomy to learn about the eruptive activities on distant astronomical objects. Through several cases, we illustrate what we can learn from the TDS charts. Furthermore, we apply the TDS method to 74 flares equal to or greater than the M5.0 class, and reach the following statistical results. First, EUV peaks are always behind the soft X-ray (SXR) peaks and stronger flares tend to have faster cooling rates. There is a power-law correlation between the peak delay times and the cooling rates, suggesting a coherent cooling process of flares from SXR to EUV emissions. Second, there are two distinct temperature drift patterns, called Type I and Type II. For Type I flares, the enhanced emission drifts from high to low temperature like a quadrilateral, whereas for Type II flares the drift pattern looks like a triangle. Statistical analysis suggests that Type II flares are more impulsive than Type I flares. Third, for late-phase flares, the peak intensity ratio of the late phase to the main phase is roughly correlated with the flare class, and the flares with a strong late phase are all confined. We believe that the re-deposition of the energy carried by a flux rope, which unsuccessfully erupts out, into thermal emissions is responsible for the strong late phase found in a confined flare. Furthermore, we show the signatures of the flare thermodynamic process in the chromosphere and transition region in the TDS charts. These results provide new clues to advance our understanding of the thermodynamic processes of solar flares and associated solar eruptions, e.g., coronal mass ejections.

  7. Radiative hazard of solar flares in the nearterrestrial cosmic space

    Kolomenskij, A.V.; Petrov, V.M.; Zil', M.V.; Eremkina, T.M.

    1978-01-01

    Simulation of radiation enviroment due to solar cosmic rays was carried out in the near-terrestrial space. Systematized are the data on cosmic ray flux and spectra detected during 19-th and 20-th cycles of solar activity. 127 flares are considered with proton fluxes of more than 10 proton/cm 2 at energies higher than 30 MeV. Obtained are distribution functions of intervals between flares, flux distribution of flares and characteristic rigidity, and also distribution of magnetic disturbances over Dsub(st)-variation amplitude. The totality of these distributions presents the statistic model of radiation enviroment caused by solar flare protons for the period of maximum solar .activity. This model is intended for estimation of radiation hazard at manned cosmic flights

  8. Multiple active forms of thrombin. IV. Relative activities of meizothrombins

    Doyle, M.F.; Mann, K.G. (Univ. of Vermont College of Medicine, Burlington (USA))

    1990-06-25

    The prothrombin activation intermediates meizothrombin and meizothrombin(desF1) (meizothrombin that has been autoproteolyzed to remove fragment 1) have been obtained in a relatively pure, active form with minimal autolysis, making them suitable for enzymatic characterization. When compared at equimolar concentrations, alpha-thrombin, fragment 1.2+ alpha-thrombin, meizothrombin(desF1), and meizothrombin have approximately 100, 100, 10, and 1% activity, respectively, toward the macromolecular substrates factor V, fibrinogen, and platelets. The difference in activity of these four enzymes cannot be attributed to alterations in the catalytic triad, as all four enzymes have nearly identical catalytic efficiency toward the chromogenic substrate S2238. Further, the ability of meizothrombin and meizothrombin(desF1) to activate protein C was 75% of the activity exhibited by alpha-thrombin or fragment 1.2+ alpha-thrombin. All four enzymes bind to thrombomodulin, as judged by the enhanced rate of protein C activation upon preincubation of the enzymes with thrombomodulin. The extent of rate enhancement varied, with meizothrombin/thrombomodulin exhibiting only 50% of the alpha-thrombin/thrombomodulin rate. This difference in rate is not due to a decreased affinity of the meizothrombin for thrombomodulin since the apparent dissociation constants for the alpha-thrombin-thrombomodulin complex and the meizothrombin-thrombomodulin complex are virtually identical. The difference in the observed rate is due in part to the higher Km for protein C exhibited by the meizothrombin-thrombomodulin complex. Incubation of the thrombomodulin-enzyme complex with phospholipid vesicles caused an increase in the protein C activation rates. The kinetic constants for protein C activation in the presence of phospholipid are virtually identical for these enzyme-thrombomodulin complexes.

  9. Multiple active forms of thrombin. IV. Relative activities of meizothrombins

    Doyle, M.F.; Mann, K.G.

    1990-01-01

    The prothrombin activation intermediates meizothrombin and meizothrombin(desF1) (meizothrombin that has been autoproteolyzed to remove fragment 1) have been obtained in a relatively pure, active form with minimal autolysis, making them suitable for enzymatic characterization. When compared at equimolar concentrations, alpha-thrombin, fragment 1.2+ alpha-thrombin, meizothrombin(desF1), and meizothrombin have approximately 100, 100, 10, and 1% activity, respectively, toward the macromolecular substrates factor V, fibrinogen, and platelets. The difference in activity of these four enzymes cannot be attributed to alterations in the catalytic triad, as all four enzymes have nearly identical catalytic efficiency toward the chromogenic substrate S2238. Further, the ability of meizothrombin and meizothrombin(desF1) to activate protein C was 75% of the activity exhibited by alpha-thrombin or fragment 1.2+ alpha-thrombin. All four enzymes bind to thrombomodulin, as judged by the enhanced rate of protein C activation upon preincubation of the enzymes with thrombomodulin. The extent of rate enhancement varied, with meizothrombin/thrombomodulin exhibiting only 50% of the alpha-thrombin/thrombomodulin rate. This difference in rate is not due to a decreased affinity of the meizothrombin for thrombomodulin since the apparent dissociation constants for the alpha-thrombin-thrombomodulin complex and the meizothrombin-thrombomodulin complex are virtually identical. The difference in the observed rate is due in part to the higher Km for protein C exhibited by the meizothrombin-thrombomodulin complex. Incubation of the thrombomodulin-enzyme complex with phospholipid vesicles caused an increase in the protein C activation rates. The kinetic constants for protein C activation in the presence of phospholipid are virtually identical for these enzyme-thrombomodulin complexes

  10. Reconstruction of a Large-scale Pre-flare Coronal Current Sheet Associated with a Homologous X-shaped Flare

    Jiang, Chaowei; Yan, Xiaoli; Feng, Xueshang; Duan, Aiying; Hu, Qiang; Zuo, Pingbing; Wang, Yi

    2017-11-01

    As a fundamental magnetic structure in the solar corona, electric current sheets (CSs) can form either prior to or during a solar flare, and they are essential for magnetic energy dissipation in the solar corona because they enable magnetic reconnection. However, the static reconstruction of a CS is rare, possibly due to limitations that are inherent in the available coronal field extrapolation codes. Here we present the reconstruction of a large-scale pre-flare CS in solar active region 11967 using an MHD-relaxation model constrained by the SDO/HMI vector magnetogram. The CS is associated with a set of peculiar homologous flares that exhibit unique X-shaped ribbons and loops occurring in a quadrupolar magnetic configuration.This is evidenced by an ’X’ shape, formed from the field lines traced from the CS to the photosphere. This nearly reproduces the shape of the observed flare ribbons, suggesting that the flare is a product of the dissipation of the CS via reconnection. The CS forms in a hyperbolic flux tube, which is an intersection of two quasi-separatrix layers. The recurrence of the X-shaped flares might be attributed to the repetitive formation and dissipation of the CS, as driven by the photospheric footpoint motions. These results demonstrate the power of a data-constrained MHD model in reproducing a CS in the corona as well as providing insight into the magnetic mechanism of solar flares.

  11. DETERMINING HEATING RATES IN RECONNECTION FORMED FLARE LOOPS OF THE M8.0 FLARE ON 2005 MAY 13

    Liu Wenjuan; Qiu Jiong; Longcope, Dana W. [Department of Physics, Montana State University, Bozeman, MT 59717-3840 (United States); Caspi, Amir [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States)

    2013-06-20

    We analyze and model an M8.0 flare on 2005 May 13 observed by the Transition Region and Coronal Explorer and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) to determine the energy release rate from magnetic reconnection that forms and heats numerous flare loops. The flare exhibits two ribbons in UV 1600 A emission. Analysis shows that the UV light curve at each flaring pixel rises impulsively within a few minutes, and decays slowly with a timescale longer than 10 minutes. Since the lower atmosphere (the transition region and chromosphere) responds to energy deposit nearly instantaneously, the rapid UV brightening is thought to reflect the energy release process in the newly formed flare loop rooted at the footpoint. In this paper, we utilize the spatially resolved (down to 1'') UV light curves and the thick-target hard X-ray emission to construct heating functions of a few thousand flare loops anchored at the UV footpoints, and compute plasma evolution in these loops using the enthalpy-based thermal evolution of loops model. The modeled coronal temperatures and densities of these flare loops are then used to calculate coronal radiation. The computed soft X-ray spectra and light curves compare favorably with those observed by RHESSI and by the Geostationary Operational Environmental Satellite X-ray Sensor. The time-dependent transition region differential emission measure for each loop during its decay phase is also computed with a simplified model and used to calculate the optically thin C IV line emission, which dominates the UV 1600 A bandpass during the flare. The computed C IV line emission decays at the same rate as observed. This study presents a method to constrain heating of reconnection-formed flare loops using all available observables independently, and provides insight into the physics of energy release and plasma heating during the flare. With this method, the lower limit of the total energy used to heat the flare loops in

  12. The classification of flaring states of blazars

    Resconi, E.; Franco, D.; Gross, A.; Costamante, L.; Flaccomio, E.

    2009-08-01

    Aims: The time evolution of the electromagnetic emission from blazars, in particular high-frequency peaked sources (HBLs), displays irregular activity that has not yet been understood. In this work we report a methodology capable of characterizing the time behavior of these variable objects. Methods: The maximum likelihood blocks (MLBs) is a model-independent estimator that subdivides the light curve into time blocks, whose length and amplitude are compatible with states of constant emission rate of the observed source. The MLBs yield the statistical significance in the rate variations and strongly suppresses the noise fluctuations in the light curves. We applied the MLBs for the first time on the long term X-ray light curves (RXTE/ASM) of Mkn 421, Mkn 501, 1ES 1959+650, and 1ES 2155-304, more than 10 years of observational data (1996-2007). Using the MLBs interpretation of RXTE/ASM data, the integrated time flux distribution is determined for each single source considered. We identify in these distributions the characteristic level, as well as the flaring states of the blazars. Results: All the distributions show a significant component at negative flux values, most probably caused by an uncertainty in the background subtraction and by intrinsic fluctuations of RXTE/ASM. This effect concerns in particular short time observations. To quantify the probability that the intrinsic fluctuations give rise to a false identification of a flare, we study a population of very faint sources and their integrated time-flux distribution. We determine duty cycle or fraction of time a source spent in the flaring state of the source Mkn 421, Mkn 501, 1ES 1959+650 and 1ES 2155-304. Moreover, we study the random coincidences between flares and generic sporadic events such as high-energy neutrinos or flares in other wavelengths.

  13. Energy spectrum of flares of the UV Cet stars and physical measunings of several statistical characteristics of these stars

    Gershberg, R.E.

    1985-01-01

    Accounting the observed power character of the energy spectrum of flares of the UV Cet-type stars, several statistical characterisitics of there stars are considered. It is shown that a mean amplitude of flares is mainly determined with an amplitude of the faintest flare that can be registered at the star under consideration and therefore - contrary to tradition - the mean flare amplitude cannot be used as a measure of a flare activity of the star. Mean frequencuy of flares registered at a flare star dependes statisticaally certainly ona an absolute magneitude of the star - contary to wide spread belief, true mean frequencies are higher at brighter stars. On the basis of the Cataloque of flare stars in Pleiades by Haro, Chavira and Gonzalez a luminosity function of therese stars is constructed. Using this function and the revealed dependence of flare mean frequencies on stellar absolute magnitudes, a distribution of flare stars in Pleiades along flare mean frequencies is constructed. This shows that the cluster contains flare stars with mean frequencies of photographically registered flares from 10 -4 to 10 -2 hour -1 or within even narrower interval of frequencies and the total number of such stars in the cluster exceeds 1100

  14. Flares of Orion population variables in the association Taurus T3

    Khodzhaev, A.S.; AN Armyanskoj SSR, Byurakan. Astrofizicheskaya Observatoriya)

    1987-01-01

    Thirteen new flare stars, proved to be irregular variables of Orion Population, were discovered from a study of the Taurus Dark Cloud region by the homogeneous photographic multipose method on the wide angle Schmidt telescopes of the Byurakan Astorphysical Observatory. Seventeen flares on these stars were detected for about 750 hours of the effective observing time. The analysis of the complicated light curves of these flares shows a great variety and multiplicity of this phenomenon and various dynamics of flare energy release processes. The existence of flare stars with some properties typical for both of the T Tauri and UV Ceti stars simulteneously indicates nonstable stars. The population of flare stars in the Taurus Dark Cloud region is apparently as young as in Orion and Monoceros

  15. Optical flare observed in the flaring gamma-ray blazar Ton 599

    Pursimo, Tapio; Sagues, Ana; Telting, John; Ojha, Roopesh

    2017-11-01

    We report optical photometry of the flat spectrum radio quasar Ton 599, obtained with the 2.56m Nordic Optical Telescope in La Palma, to look for any enhanced optical activity associated with a recent flare in the daily averaged gamma-ray flux (ATel#10931, ATel#10937).

  16. Parameterization of solar flare dose

    Lamarche, A.H.; Poston, J.W.

    1996-01-01

    A critical aspect of missions to the moon or Mars will be the safety and health of the crew. Radiation in space is a hazard for astronauts, especially high-energy radiation following certain types of solar flares. A solar flare event can be very dangerous if astronauts are not adequately shielded because flares can deliver a very high dose in a short period of time. The goal of this research was to parameterize solar flare dose as a function of time to see if it was possible to predict solar flare occurrence, thus providing a warning time. This would allow astronauts to take corrective action and avoid receiving a dose greater than the recommended limit set by the National Council on Radiation Protection and Measurements (NCRP)

  17. Morphology and velocity field of the large flare on the solar disc on July 14, 1980

    Xuan, J.; Li, Z.

    1982-01-01

    The active region morphology and the features of solar radio bursts and the sight-line velocity distribution of a flare of importance 3B on the solar disk (AR 2562) on July 14, 1980, are discussed. The preliminary analysis made here suggests that measurement of the velocity fields of active regions is important in treating flare mechanisms. It is noted that a few hours before the eruption of the flare, the penumbral fibers of the sunspots on the corresponding photospheric part under the flare rapidly attenuated. It is thought that the instability of the flare may derive from the rapid changes occurring in the magnetic boundary conditions of the photosphere. These in turn denote the rapid emergence, subsidence, or dissipation of the magnetic flux. The spectra of the active filament in the later period of the flare are seen as indicating that most of the ejection matter was rolling, in addition to ascending or descending

  18. Adaptive Active Noise Suppression Using Multiple Model Switching Strategy

    Quanzhen Huang

    2017-01-01

    Full Text Available Active noise suppression for applications where the system response varies with time is a difficult problem. The computation burden for the existing control algorithms with online identification is heavy and easy to cause control system instability. A new active noise control algorithm is proposed in this paper by employing multiple model switching strategy for secondary path varying. The computation is significantly reduced. Firstly, a noise control system modeling method is proposed for duct-like applications. Then a multiple model adaptive control algorithm is proposed with a new multiple model switching strategy based on filter-u least mean square (FULMS algorithm. Finally, the proposed algorithm was implemented on Texas Instruments digital signal processor (DSP TMS320F28335 and real time experiments were done to test the proposed algorithm and FULMS algorithm with online identification. Experimental verification tests show that the proposed algorithm is effective with good noise suppression performance.

  19. Automated flare forecasting using a statistical learning technique

    Yuan, Yuan; Shih, Frank Y.; Jing, Ju; Wang, Hai-Min

    2010-08-01

    We present a new method for automatically forecasting the occurrence of solar flares based on photospheric magnetic measurements. The method is a cascading combination of an ordinal logistic regression model and a support vector machine classifier. The predictive variables are three photospheric magnetic parameters, i.e., the total unsigned magnetic flux, length of the strong-gradient magnetic polarity inversion line, and total magnetic energy dissipation. The output is true or false for the occurrence of a certain level of flares within 24 hours. Experimental results, from a sample of 230 active regions between 1996 and 2005, show the accuracies of a 24-hour flare forecast to be 0.86, 0.72, 0.65 and 0.84 respectively for the four different levels. Comparison shows an improvement in the accuracy of X-class flare forecasting.

  20. Automated flare forecasting using a statistical learning technique

    Yuan Yuan; Shih, Frank Y.; Jing Ju; Wang Haimin

    2010-01-01

    We present a new method for automatically forecasting the occurrence of solar flares based on photospheric magnetic measurements. The method is a cascading combination of an ordinal logistic regression model and a support vector machine classifier. The predictive variables are three photospheric magnetic parameters, i.e., the total unsigned magnetic flux, length of the strong-gradient magnetic polarity inversion line, and total magnetic energy dissipation. The output is true or false for the occurrence of a certain level of flares within 24 hours. Experimental results, from a sample of 230 active regions between 1996 and 2005, show the accuracies of a 24-hour flare forecast to be 0.86, 0.72, 0.65 and 0.84 respectively for the four different levels. Comparison shows an improvement in the accuracy of X-class flare forecasting. (research papers)

  1. Solar flares and the cosmic ray intensity

    Hatton, C.J.

    1980-01-01

    The relationship between the cosmic ray intensity and solar activity during solar cycle 20 is discussed. A model is developed whereby it is possible to simulate the observed cosmic ray intensity from the observed number of solar flares of importance >= 1. This model leads to a radius for the modulation region of 60-70 AU. It is suggested that high speed solar streams also made a small contribution to the modulation of cosmic rays during solar cycle 20. (orig.)

  2. Epstein-Barr virus and disease activity in multiple sclerosis

    D. Buljevac (Dragan); H.Z. Flach (Zwenneke); J. Groen (Jan); P.A. van Doorn (Pieter); F.G.A. van der Meché (Frans); R.Q. Hintzen (Rogier); W.C.J. Hop (Wim); A.D.M.E. Osterhaus (Albert); G.J.J. van Doornum (Gerard)

    2005-01-01

    textabstractOBJECTIVES: To study in relapsing-remitting (RR) multiple sclerosis (MS) whether exacerbations and brain activity as measured by magnetic resonance imaging (MRI) are associated with plasma levels of anti-Epstein Barr (EBV) antibodies and EBV DNA. METHODS: This was a prospective study

  3. Developmental Trampoline Activities for Individuals with Multiple Handicapping Conditions.

    Thomas, Bill

    1979-01-01

    The use of trampoline activities with multiple handicapped students is discussed. Management considerations in safety are noted, and developmental trampoline skills are listed beginning with bouncing for stimulation. Progression to limited independence and finally independent jumping is described. The position statement of the American Alliance…

  4. Low leucocyte myeloperoxidase activity in patients with multiple sclerosis

    Ramsaransing, G; Teelken, A; Prokopenko, VM; Arutjunyan, AV; De Keyser, J

    The gene for myeloperoxidase (MPO) has been implicated in multiple sclerosis (MS). By measuring H2O2 dependent oxidation of 3,3'5,5'-tetramethylbenzidine with spectrophotometry the authors investigated MPO activity in peripheral blood leucocytes from 42 patients with MS (12 with secondary

  5. Stellar flare oscillations: evidence for oscillatory reconnection and evolution of MHD modes

    Doyle, J. G.; Shetye, J.; Antonova, A. E.; Kolotkov, D. Y.; Srivastava, A. K.; Stangalini, M.; Gupta, G. R.; Avramova, A.; Mathioudakis, M.

    2018-04-01

    Here, we report on the detection of a range of quasi-periodic pulsations (20-120 s; QPPs) observed during flaring activity of several magnetically active dMe stars, namely AF Psc, CR Dra, GJ 3685A, Gl 65, SDSS J084425.9+513830, and SDSS J144738.47+035312.1 in the GALEX NUV filter. Based on a solar analogy, this work suggests that many of these flares may be triggered by external drivers creating a periodic reconnection in the flare current sheet or an impulsive energy release giving rise to an avalanche of periodic bursts that occur at time intervals that correspond to the detected periods, thus generating QPPs in their rising and peak phases. Some of these flares also show fast QPPs in their decay phase, indicating the presence of fast sausage mode oscillations either driven externally by periodic reconnection or intrinsically in the post-flare loop system during the flare energy release.

  6. “Dandelion” Filament Eruption and Coronal Waves Associated with a Solar Flare on 2011 February 16

    Cabezas, Denis P.; Ishitsuka, Mutsumi; Ishitsuka, José K.; Martínez, Lurdes M.; Buleje, Yovanny J.; Morita, Satoshi; Asai, Ayumi; UeNo, Satoru; Ishii, Takako T.; Kitai, Reizaburo; Takasao, Shinsuke; Yoshinaga, Yusuke; Otsuji, Kenichi; Shibata, Kazunari

    2017-01-01

    Coronal disturbances associated with solar flares, such as H α Moreton waves, X-ray waves, and extreme ultraviolet (EUV) coronal waves, are discussed herein in relation to magnetohydrodynamic fast-mode waves or shocks in the corona. To understand the mechanism of coronal disturbances, full-disk solar observations with high spatial and temporal resolution over multiple wavelengths are of crucial importance. We observed a filament eruption, whose shape is like a “dandelion,” associated with the M1.6 flare that occurred on 2011 February 16 in H α images taken by the Flare Monitoring Telescope at Ica University, Peru. We derive the three-dimensional velocity field of the erupting filament. We also identify winking filaments that are located far from the flare site in the H α images, whereas no Moreton wave is observed. By comparing the temporal evolution of the winking filaments with those of the coronal wave seen in the EUV images data taken by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and by the Extreme Ultraviolet Imager on board the Solar Terrestrial Relations Observatory-Ahead , we confirm that the winking filaments were activated by the EUV coronal wave.

  7. “Dandelion” Filament Eruption and Coronal Waves Associated with a Solar Flare on 2011 February 16

    Cabezas, Denis P.; Ishitsuka, Mutsumi; Ishitsuka, José K. [Geophysical Institute of Peru, Calle Badajoz 169, Mayorazgo IV Etapa, Ate Vitarte, Lima (Peru); Martínez, Lurdes M.; Buleje, Yovanny J. [Centro de Investigación del Estudio de la Actividad Solar y sus Efectos Sobre la Tierra, Facultad de Ciencias, Universidad Nacional San Luis Gonzaga de Ica, Av. Los Maestros S/N, Ica (Peru); Morita, Satoshi [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Asai, Ayumi [Unit of Synergetic Studies for Space, Kyoto University, Sakyo, Kyoto, 606-8502 (Japan); UeNo, Satoru; Ishii, Takako T.; Kitai, Reizaburo; Takasao, Shinsuke; Yoshinaga, Yusuke; Otsuji, Kenichi; Shibata, Kazunari, E-mail: denis@kwasan.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto, 607-8471 (Japan)

    2017-02-10

    Coronal disturbances associated with solar flares, such as H α Moreton waves, X-ray waves, and extreme ultraviolet (EUV) coronal waves, are discussed herein in relation to magnetohydrodynamic fast-mode waves or shocks in the corona. To understand the mechanism of coronal disturbances, full-disk solar observations with high spatial and temporal resolution over multiple wavelengths are of crucial importance. We observed a filament eruption, whose shape is like a “dandelion,” associated with the M1.6 flare that occurred on 2011 February 16 in H α images taken by the Flare Monitoring Telescope at Ica University, Peru. We derive the three-dimensional velocity field of the erupting filament. We also identify winking filaments that are located far from the flare site in the H α images, whereas no Moreton wave is observed. By comparing the temporal evolution of the winking filaments with those of the coronal wave seen in the EUV images data taken by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and by the Extreme Ultraviolet Imager on board the Solar Terrestrial Relations Observatory-Ahead , we confirm that the winking filaments were activated by the EUV coronal wave.

  8. Flare research with the NASA/MSFC vector magnetograph - Observed characteristics of sheared magnetic fields that produce flares

    Moore, R. L.; Hagyard, M. J.; Davis, J. M.

    1987-01-01

    The present MSFC Vector Magnetograph has sufficient spatial resolution (2.7 arcsec pixels) and sensitivity to the transverse field (the noise level is about 100 gauss) to map the transverse field in active regions accurately enough to reveal key aspects of the sheared magnetic fields commonly found at flare sites. From the measured shear angle along the polarity inversion line in sites that flared and in other shear sites that didn't flare, evidence is found that a sufficient condition for a flare to occur in 1000 gauss fields in and near sunspots is that both: (1) the maximum shear angle exceed 85 degrees; and (2) the extent of strong shear (shear angle of greater than 80 degrees) exceed 10,000 km.

  9. Transient magnetic field changes in flares

    Patterson, A.; Zirin, H.

    1981-01-01

    Magnetic changes have been detected with the videomagnetograph (VMG) at Big Bear during two large flares on 1979 November 5. Two kinds of changes were detected in both flares: a decrease in satellite field strength near the locus of the flare and the appearance of strong transient fields during the peak of the flare. We explain why we believe that the observed effects are real and not instrumental and discuss their significance for flare studies

  10. Chandra Captures Flare From Brown Dwarf

    2000-07-01

    The first flare ever seen from a brown dwarf, or failed star, was detected by NASA's Chandra X-ray Observatory. The bright X-ray flare has implications for understanding the explosive activity and origin of magnetic fields of extremely low mass stars. Chandra detected no X-rays at all from LP 944-20 for the first nine hours of a twelve hour observation, then the source flared dramatically before it faded away over the next two hours. "We were shocked," said Dr. Robert Rutledge of the California Institute of Technology in Pasadena, the lead author on the discovery paper to appear in the July 20 issue of Astrophysical Journal Letters. "We didn't expect to see flaring from such a lightweight object. This is really the 'mouse that roared.'" Chandra LP 944-20 X-ray Image Press Image and Caption The energy emitted in the brown dwarf flare was comparable to a small solar flare, and was a billion times greater than observed X-ray flares from Jupiter. The flaring energy is believed to come from a twisted magnetic field. "This is the strongest evidence yet that brown dwarfs and possibly young giant planets have magnetic fields, and that a large amount of energy can be released in a flare," said Dr. Eduardo Martin, also of Caltech and a member of the team. Professor Gibor Basri of the University of California, Berkeley, the principal investigator for this observation, speculated that the flare "could have its origin in the turbulent magnetized hot material beneath the surface of the brown dwarf. A sub-surface flare could heat the atmosphere, allowing currents to flow and give rise to the X-ray flare -- like a stroke of lightning." LP 944-20 is about 500 million years old and has a mass that is about 60 times that of Jupiter, or 6 percent that of the Sun. Its diameter is about one-tenth that of the Sun and it has a rotation period of less than five hours. Located in the constellation Fornax in the southern skies, LP 944-20 is one of the best studied brown dwarfs because it is

  11. Narrow-band radio flares from red dwarf stars

    White, S.M.; Kundu, M.R.; Jackson, P.D.

    1986-12-01

    VLA observations of narrow-band behavior in 20 cm flares from two red dwarf stars, L726 - 8A and AD Leo, are reported. The flare on L726 - 8A was observed at 1415 and 1515 MHz; the flux and the evolution differed significantly at the two frequencies. The flare on AD Leo lasted for 2 hr at 1415 MHz but did not appear at 1515 MHz. The AD Leo flare appears to rule out a source drifting through the stellar corona and is unlikely to be due to plasma emission. In the cyclotron maser model the narrow-band behavior reflects the range of magnetic fields present within the source. The apparent constancy of this field for 2 hr is difficult to understand if magnetic reconnection is the source of energy for the flare. The consistent polarization exhibited by red dwarf flares at 20 cm may be related to stellar activity cycles, and changes in this polarization will permit measuring the length of these cycles. 22 references.

  12. Narrow-band radio flares from red dwarf stars

    White, Stephen M.; Kundu, Mukul R.; Jackson, Peter D.

    1986-01-01

    VLA observations of narrow-band behavior in 20 cm flares from two red dwarf stars, L726 - 8A and AD Leo, are reported. The flare on L726 - 8A was observed at 1415 and 1515 MHz; the flux and the evolution differed significantly at the two frequencies. The flare on AD Leo lasted for 2 hr at 1415 MHz but did not appear at 1515 MHz. The AD Leo flare appears to rule out a source drifting through the stellar corona and is unlikely to be due to plasma emission. In the cyclotron maser model the narrow-band behavior reflects the range of magnetic fields present within the source. The apparent constancy of this field for 2 hr is difficult to understand if magnetic reconnection is the source of energy for the flare. The consistent polarization exhibited by red dwarf flares at 20 cm may be related to stellar activity cycles, and changes in this polarization will permit measuring the length of these cycles.

  13. Magnetohydrodynamic Simulations for Studying Solar Flare Trigger Mechanism

    Muhamad, J.; Kusano, K.; Inoue, S.; Shiota, D. [Institute for Space-Earth Environmental Research, Nagoya University, Furocho, Chikusa-ku, Nagoya, Aichi, 464-8601 (Japan)

    2017-06-20

    In order to understand the flare trigger mechanism, we conduct three-dimensional magnetohydrodynamic simulations using a coronal magnetic field model derived from data observed by the Hinode satellite. Several types of magnetic bipoles are imposed into the photospheric boundary of the Nonlinear Force-free Field model of Active Region (AR) NOAA 10930 on 2006 December 13, to investigate what kind of magnetic disturbance may trigger the flare. As a result, we confirm that certain small bipole fields, which emerge into the highly sheared global magnetic field of an AR, can effectively trigger a flare. These bipole fields can be classified into two groups based on their orientation relative to the polarity inversion line: the so-called opposite polarity, and reversed shear structures, as suggested by Kusano et al. We also investigate the structure of the footpoints of reconnected field lines. By comparing the distribution of reconstructed field lines and observed flare ribbons, the trigger structure of the flare can be inferred. Our simulation suggests that the data-constrained simulation, taking into account both the large-scale magnetic structure and small-scale magnetic disturbance (such as emerging fluxes), is a good way to discover a flare-producing AR, which can be applied to space weather prediction.

  14. Health and exposure assessment of flare gas emissions

    Kindzierski, W.B.; Byrne-Lewis, C.; Probert, S.

    2000-01-01

    The incomplete combustion of flare gases produces pollutants such as volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) which are cause for concern for public health. Some of the concerns relate to potential long-term cumulative health effects from exposure to hazardous air pollutants including benzene, styrene, naphthalene, and benzopyrene. This study demonstrated that several factors should be taken into account when considering the importance of flaring and human exposure to flare gas emissions. Most flare stacks are located in rural areas, but most time-availability studies have been done on urban populations where the majority of people spend their time indoors. It was recommended that more time-activity studies are needed to emphasize the behaviour of rural populations which are most susceptible to exposure from pollutants from flaring. It was concluded that higher indoor air concentrations exist for many VOCs and PAHs compared to outdoors, but in these instances, indoor sources are the major contributors to indoor air concentrations. It was recommended that health assessments of hazardous air pollutants emitted from gas flaring has to take into account the indoor setting and other background exposures in order to provide useful information for decision makers. 49 refs., 8 tabs., 1 fig

  15. Flare Prediction Using Photospheric and Coronal Image Data

    Jonas, E.; Shankar, V.; Bobra, M.; Recht, B.

    2016-12-01

    We attempt to forecast M-and X-class solar flares using a machine-learning algorithm and five years of image data from both the Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Assembly (AIA) instruments aboard the Solar Dynamics Observatory. HMI is the first instrument to continuously map the full-disk photospheric vector magnetic field from space (Schou et al., 2012). The AIA instrument maps the transition region and corona using various ultraviolet wavelengths (Lemen et al., 2012). HMI and AIA data are taken nearly simultaneously, providing an opportunity to study the entire solar atmosphere at a rapid cadence. Most flare forecasting efforts described in the literature use some parameterization of solar data - typically of the photospheric magnetic field within active regions. These numbers are considered to capture the information in any given image relevant to predicting solar flares. In our approach, we use HMI and AIA images of solar active regions and a deep convolutional kernel network to predict solar flares. This is effectively a series of shallow-but-wide random convolutional neural networks stacked and then trained with a large-scale block-weighted least squares solver. This algorithm automatically determines which patterns in the image data are most correlated with flaring activity and then uses these patterns to predict solar flares. Using the recently-developed KeystoneML machine learning framework, we construct a pipeline to process millions of images in a few hours on commodity cloud computing infrastructure. This is the first time vector magnetic field images have been combined with coronal imagery to forecast solar flares. This is also the first time such a large dataset of solar images, some 8.5 terabytes of images that together capture over 3000 active regions, has been used to forecast solar flares. We evaluate our method using various flare prediction windows defined in the literature (e.g. Ahmed et al., 2013) and a novel per

  16. Critical Height of the Torus Instability in Two-ribbon Solar Flares

    Wang, Dong; Liu, Rui; Wang, Yuming; Liu, Kai; Chen, Jun; Liu, Jiajia; Zhou, Zhenjun [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Min, E-mail: rliu@ustc.edu.cn [Department of Mathematics and Physics, Anhui Jianzhu University, Hefei 230601 (China)

    2017-07-01

    We studied the background field for 60 two-ribbon flares of M-and-above classes during 2011–2015. These flares are categorized into two groups, i.e., eruptive and confined flares, based on whether a flare is associated with a coronal mass ejection or not. The background field of source active regions is approximated by a potential field extrapolated from the B {sub z} component of vector magnetograms provided by the Helioseismic and Magnetic Imager. We calculated the decay index n of the background field above the flaring polarity inversion line, and defined a critical height h {sub crit} corresponding to the theoretical threshold ( n {sub crit} = 1.5) of the torus instability. We found that h {sub crit} is approximately half of the distance between the centroids of opposite polarities in active regions and that the distribution of h {sub crit} is bimodal: it is significantly higher for confined flares than for eruptive ones. The decay index increases monotonously with increasing height for 86% (84%) of the eruptive (confined) flares but displays a saddle-like profile for the rest, 14% (16%), which are found exclusively in active regions of multipolar field configuration. Moreover, n at the saddle bottom is significantly smaller in confined flares than that in eruptive ones. These results highlight the critical role of background field in regulating the eruptive behavior of two-ribbon flares.

  17. Latitudinal distribution of soft X-ray flares and dispairty in butterfly diagram

    Pandey, K. K.; Yellaiah, G.; Hiremath, K. M.

    2015-04-01

    We present statistical analysis of about 63000 soft X-ray flare (class≥C) observed by geostationary operational environmental satellite (GOES) during the period 1976-2008. Class wise occurrence of soft X-ray (SXR) flare is in declining trend since cycle 21. The distribution pattern of cycle 21 shows the transit of hemispheric dominance of flare activity from northern to southern hemisphere and remains there during cycle 22 and 23. During the three cycles, 0-100, 21-300 latitude belts in southern hemisphere (SH) and 31-400 latitude belt in northern hemisphere (NH) are mightier. The 11-200 latitude belt of both hemisphere is mightiest. Correlation coefficient between consecutive latitude appears to be increasing from equator to poleward in northern hemisphere whereas pole to equatorward in southern hemisphere. Slope of the regression line fitted with asymmetry time series of daily flare counts is negative in all three cycles for different classes of flares. The yearly asymmetry curve fitted by a sinusoidal function varies from 5.6 to 11 years period and depends upon the intensity of flare. Variation, of curve fitted with wings of butterfly diagram, from first to second order polynomial suggests that latitudinal migration of flare activity varies from cycle to cycle, northern to southern hemisphere. The variation in slope of the butterfly wing of different flare class indicates the non uniform migration of flare activity.

  18. Solar Features - Solar Flares - Patrol

    National Oceanic and Atmospheric Administration, Department of Commerce — The H-alpha Flare Patrol identifies time periods each day when the sun is being continuously monitored by select ground-based solar observatories.

  19. Solar flares at submillimeter wavelengths

    Krucker, S.; Gimenez de Castro, C.G.; Hudson, H. S.; Trottet, G.; Bastian, T.S.; Hales, A.S.; Kašparová, Jana; Klein, K. L.; Kretzschmar, M.; Luethi, T.; Mackinnon, A.; Pohjolainen, S.; White, S.M.

    2013-01-01

    Roč. 21, č. 1 (2013), 58/1-58/45 ISSN 0935-4956 Institutional support: RVO:67985815 Keywords : Sun * flares * radio observations Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 13.312, year: 2013

  20. The solar-flare infrared continuum: observational techniques and upper limits

    Hudson, H.S.

    1975-01-01

    Exploratory observations at 20μ and 350 μ have determined detection thresholds for solar flares in these wavelengths. In the 20μ range solar atmospheric fluctuations (the 'temperature field') set the basic limits on flare detectability at approximately 5K; at 350μ the extinction in the Earth's atmosphere provides the basic limitation of approximately 30 K. These thresholds are low enough for the successful detection of several infrared-emitting components of large flares. Limited observing time and lack of solar activity have prevented observations of large flares up to the present, but the techniques promise to be extremely useful in the future. The upper limits obtained thus far, for subflares, indicate that the thickness of the Hα flare region does not exceed approximately 10 km. This result confirms the conclusion of Suemoto and Hiei (1959) regarding the small effective thickness of the Hα-emitting regions in solar flares. (Auth.)

  1. Variations of the Hβ-emission line during a large flare on UV Ceti

    Moffett, T.J.; Evans, D.S.; Ferland, G.

    1977-01-01

    Simultaneous high-speed photometry and photoelectric scanner observations of the Hβ-line were obtained for five flare events, one a major flare, on UV Ceti on 1975 January 6. The relative increase in the intensity of the Hβ-line during the large flare was much greater than the relative continuum rise as measured both by the scanner and by broad-band photometric observations. In Hβ the flare lasted nearly 30 times as long as in the continuum. Peak intensity in the Hβ-line occurred later than the continuum maximum. The possibility of using emission line observations to detect flare activity on early spectral-type stars (dK - dG) is discussed. Some speculations on the mechanism of flare production are indulged. (author)

  2. Current Fragmentation and Particle Acceleration in Solar Flares

    Cargill, P. J.; Vlahos, L.; Baumann, G.; Drake, J. F.; Nordlund, Å.

    2012-11-01

    Particle acceleration in solar flares remains an outstanding problem in plasma physics and space science. While the observed particle energies and timescales can perhaps be understood in terms of acceleration at a simple current sheet or turbulence site, the vast number of accelerated particles, and the fraction of flare energy in them, defies any simple explanation. The nature of energy storage and dissipation in the global coronal magnetic field is essential for understanding flare acceleration. Scenarios where the coronal field is stressed by complex photospheric motions lead to the formation of multiple current sheets, rather than the single monolithic current sheet proposed by some. The currents sheets in turn can fragment into multiple, smaller dissipation sites. MHD, kinetic and cellular automata models are used to demonstrate this feature. Particle acceleration in this environment thus involves interaction with many distributed accelerators. A series of examples demonstrate how acceleration works in such an environment. As required, acceleration is fast, and relativistic energies are readily attained. It is also shown that accelerated particles do indeed interact with multiple acceleration sites. Test particle models also demonstrate that a large number of particles can be accelerated, with a significant fraction of the flare energy associated with them. However, in the absence of feedback, and with limited numerical resolution, these results need to be viewed with caution. Particle in cell models can incorporate feedback and in one scenario suggest that acceleration can be limited by the energetic particles reaching the condition for firehose marginal stability. Contemporary issues such as footpoint particle acceleration are also discussed. It is also noted that the idea of a "standard flare model" is ill-conceived when the entire distribution of flare energies is considered.

  3. An unorthodox X-Class Long-Duration Confined Flare

    Liu, Rui; Gou, Tingyu; Wang, Yuming; Liu, Kai [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei 230026 (China); Titov, Viacheslav S. [Predictive Science, Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States); Wang, Haimin, E-mail: rliu@ustc.edu.cn [Space Weather Research Laboratory, Center for Solar-Terrestrial Research, NJIT, Newark, NJ 07102 (United States)

    2014-07-20

    We report the observation of an X-class long-duration flare which is clearly confined. It appears as a compact-loop flare in the traditional EUV passbands (171 and 195 Å), but in the passbands sensitive to flare plasmas (94 and 131 Å), it exhibits a cusp-shaped structure above an arcade of loops like other long-duration events. Inspecting images in a running difference approach, we find that the seemingly diffuse, quasi-static cusp-shaped structure consists of multiple nested loops that repeatedly rise upward and disappear approaching the cusp edge. Over the gradual phase, we detect numerous episodes of loop rising, each lasting minutes. A differential emission measure analysis reveals that the temperature is highest at the top of the arcade and becomes cooler at higher altitudes within the cusp-shaped structure, contrary to typical long-duration flares. With a nonlinear force-free model, our analysis shows that the event mainly involves two adjacent sheared arcades separated by a T-type hyperbolic flux tube (HFT). One of the arcades harbors a magnetic flux rope, which is identified with a filament that survives the flare owing to the strong confining field. We conclude that a new emergence of magnetic flux in the other arcade triggers the flare, while the preexisting HFT and flux rope dictate the structure and dynamics of the flare loops and ribbons during the long-lasting decay phase, and that a quasi-separatrix layer high above the HFT could account for the cusp-shaped structure.

  4. DRAFTS: A DEEP, RAPID ARCHIVAL FLARE TRANSIENT SEARCH IN THE GALACTIC BULGE

    Osten, Rachel A.; Sahu, Kailash; Kowalski, Adam; Hawley, Suzanne L.

    2012-01-01

    We utilize the Sagittarius Window Eclipsing Extrasolar Planet Search Hubble Space Telescope/Advanced Camera for Surveys data set for a Deep Rapid Archival Flare Transient Search to constrain the flare rate toward the older stellar population in the Galactic bulge. During seven days of monitoring 229,293 stars brighter than V = 29.5, we find evidence for flaring activity in 105 stars between V = 20 and V = 28. We divided the sample into non-variable stars and variable stars whose light curves contain large-scale variability. The flare rate on variable stars is ∼700 times that of non-variable stars, with a significant correlation between the amount of underlying stellar variability and peak flare amplitude. The flare energy loss rates are generally higher than those of nearby well-studied single dMe flare stars. The distribution of proper motions is consistent with the flaring stars being at the distance and age of the Galactic bulge. If they are single dwarfs, then they span a range of ≈1.0-0.25 M ☉ . A majority of the flaring stars exhibit periodic photometric modulations with P < 3 days. If these are tidally locked magnetically active binary systems, then their fraction in the bulge is enhanced by a factor of ∼20 compared to the local value. These stars may be useful for placing constraints on the angular momentum evolution of cool close binary stars. Our results expand the type of stars studied for flares in the optical band, and suggest that future sensitive optical time-domain studies will have to contend with a larger sample of flaring stars than the M dwarf flare stars usually considered.

  5. Sunspot splitting triggering an eruptive flare

    Louis, Rohan E.; Puschmann, Klaus G.; Kliem, Bernhard; Balthasar, Horst; Denker, Carsten

    2014-02-01

    Aims: We investigate how the splitting of the leading sunspot and associated flux emergence and cancellation in active region NOAA 11515 caused an eruptive M5.6 flare on 2012 July 2. Methods: Continuum intensity, line-of-sight magnetogram, and dopplergram data of the Helioseismic and Magnetic Imager were employed to analyse the photospheric evolution. Filtergrams in Hα and He I 10830 Å of the Chromospheric Telescope at the Observatorio del Teide, Tenerife, track the evolution of the flare. The corresponding coronal conditions were derived from 171 Å and 304 Å images of the Atmospheric Imaging Assembly. Local correlation tracking was utilized to determine shear flows. Results: Emerging flux formed a neutral line ahead of the leading sunspot and new satellite spots. The sunspot splitting caused a long-lasting flow towards this neutral line, where a filament formed. Further flux emergence, partly of mixed polarity, as well as episodes of flux cancellation occurred repeatedly at the neutral line. Following a nearby C-class precursor flare with signs of interaction with the filament, the filament erupted nearly simultaneously with the onset of the M5.6 flare and evolved into a coronal mass ejection. The sunspot stretched without forming a light bridge, splitting unusually fast (within about a day, complete ≈6 h after the eruption) in two nearly equal parts. The front part separated strongly from the active region to approach the neighbouring active region where all its coronal magnetic connections were rooted. It also rotated rapidly (by 4.9° h-1) and caused significant shear flows at its edge. Conclusions: The eruption resulted from a complex sequence of processes in the (sub-)photosphere and corona. The persistent flows towards the neutral line likely caused the formation of a flux rope that held the filament. These flows, their associated flux cancellation, the emerging flux, and the precursor flare all contributed to the destabilization of the flux rope. We

  6. Solar Flare Track Exposure Ages in Regolith Particles: A Calibration for Transmission Electron Microscope Measurements

    Berger, Eve L.; Keller, Lindsay P.

    2015-01-01

    Mineral grains in lunar and asteroidal regolith samples provide a unique record of their interaction with the space environment. Space weathering effects result from multiple processes including: exposure to the solar wind, which results in ion damage and implantation effects that are preserved in the rims of grains (typically the outermost 100 nm); cosmic ray and solar flare activity, which result in track formation; and impact processes that result in the accumulation of vapor-deposited elements, impact melts and adhering grains on particle surfaces. Determining the rate at which these effects accumulate in the grains during their space exposure is critical to studies of the surface evolution of airless bodies. Solar flare energetic particles (mainly Fe-group nuclei) have a penetration depth of a few millimeters and leave a trail of ionization damage in insulating materials that is readily observable by transmission electron microscope (TEM) imaging. The density of solar flare particle tracks is used to infer the length of time an object was at or near the regolith surface (i.e., its exposure age). Track measurements by TEM methods are routine, yet track production rate calibrations have only been determined using chemical etching techniques [e.g., 1, and references therein]. We used focused ion beam-scanning electron microscope (FIB-SEM) sample preparation techniques combined with TEM imaging to determine the track density/exposure age relations for lunar rock 64455. The 64455 sample was used earlier by [2] to determine a track production rate by chemical etching of tracks in anorthite. Here, we show that combined FIB/TEM techniques provide a more accurate determination of a track production rate and also allow us to extend the calibration to solar flare tracks in olivine.

  7. Factors associated with endodontic flare-ups: a prospective study.

    Imura, N; Zuolo, M L

    1995-09-01

    The purpose of this prospective study was to assess the incidence of flare-ups (a severe problem requiring an unscheduled visit and treatment) among patients who received endodontic treatment by the two authors in their respective practices during a period of one year, and also to examine the correlation with pre-operative and operative variables. The results showed an incidence of 1.58% for flare-ups from 1012 endodontically treated teeth. Statistical analysis using the chi-square test (Pflare-ups were found to be positively correlated with multiple appointments, retreatment cases, periradicular pain prior to treatment, presence of radiolucent lesions, and patients taking analgesic or anti-inflammatory drugs. In contrast, there was no correlation between flare-up, and age, sex, different arch/tooth groups and the status of the pulp.

  8. Chromospheric Evaporation in an M1.8 Flare Observed by the Extreme-ultraviolet Imaging Spectrometer (EIS) on Hinode

    Doschek, G. A.; Warren, H. P.

    2012-12-01

    We discuss observations of chromospheric evaporation for a flare that occurred on 9 March 2012 near 03:30 UT obtained from the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. This was a multiple event with a strong energy input that reached the M1.8 class when observed by EIS. EIS was in raster mode and fortunately the slit reached almost the exact location of a significant energy input. Also, fortunately EIS obtained a full-CCD spectrum of the flare, i.e., the entire CCD was readout so that data were obtained for about the 500 lines identified in the EIS wavelength ranges. Chromospheric evaporation characterized by 150-200 km/s upflows was observed in several locations in multi-million degree spectral lines of flare ions such as Fe XXII, Fe XXIII, Fe XXIV, with simultaneous 20 - 60 km/s upflows in a host of million degree coronal lines from ions such as Fe XI - Fe XVI. The behavior of cooler, transition region ions such as O VI, Fe VIII, He II, and Fe X is more complex. At a point close to strong energy input, the flare ions reveal an isothermal source with a temperature close to 14 MK. At this point there is a strong downflow in cooler active region lines from ions such as Fe XIII and Fe XIV. Electron densities were obtained from density sensitive lines ratios from Fe XIII and Fe XIV. The results to be presented are refined from the preliminary data given above and combined with context AIA observations for a comparison with predictions of models of chromospheric evaporation as envisaged in the Standard Flare Model.

  9. A comparative study between clinical grading of anterior chamber flare and flare reading using the Kowa laser flare meter.

    Konstantopoulou, Kallirroi; Del'Omo, Roberto; Morley, Anne M; Karagiannis, Dimitris; Bunce, Catey; Pavesio, Carlos

    2015-10-01

    To assess the accuracy of standard clinical grading of aqueous flare in uveitis according to the Standardization of Uveitis Nomenclature consensus, and compare the results with the readings of the laser flare meter, Kowa 500. Two examiners clinically graded the flare in 110 eyes. The flare was then measured using the Kowa laser flare meter. Twenty-nine eyes were graded as anterior chamber flare +2; for 18 of these, the clinicians were in agreement, the rest differed by the order of one grade. The range of the laser flare meter for these eyes was 5.2-899.1 photons/ms. The median value was 41.4. Seventy-four eyes were graded with flare +1. Agreement was established in 51 of these eyes. Disagreement for the rest was again by the order of 1, and the flare meter range was 1.1-169.9 photons/ms, median value 18.4. For the clinical measure of flare 0, the clinicians disagreed on three out of five eyes. The flare meter readings ranged from 2.5 to 14.1 photons/ms, median value 9.9. Only two eyes were graded with flare +3 and there was one step disagreement on both of them. We found little evidence of association between the flare readings and intraocular pressure or age. Our findings suggest that clinical evaluation of aqueous flare is subjective. Compared with the Kowa laser flare meter's numeric readings, the discrepancies observed indicate that clinical grading is an approximate science. The laser flare meter provides an accurate, reproducible, non-invasive assessment of aqueous flare that can prove valuable in research and clinical decisions.

  10. Localizing Brain Activity from Multiple Distinct Sources via EEG

    George Dassios

    2014-01-01

    Full Text Available An important question arousing in the framework of electroencephalography (EEG is the possibility to recognize, by means of a recorded surface potential, the number of activated areas in the brain. In the present paper, employing a homogeneous spherical conductor serving as an approximation of the brain, we provide a criterion which determines whether the measured surface potential is evoked by a single or multiple localized neuronal excitations. We show that the uniqueness of the inverse problem for a single dipole is closely connected with attaining certain relations connecting the measured data. Further, we present the necessary and sufficient conditions which decide whether the collected data originates from a single dipole or from numerous dipoles. In the case where the EEG data arouses from multiple parallel dipoles, an isolation of the source is, in general, not possible.

  11. Sodium intake and multiple sclerosis activity and progression in BENEFIT

    Fitzgerald, Kathryn C; Munger, Kassandra L; Hartung, Hans-Peter

    2017-01-01

    OBJECTIVE: To assess whether a high-salt diet, as measured by urinary sodium concentration, is associated with faster conversion from clinically isolated syndrome (CIS) to multiple sclerosis (MS) and MS activity and disability. METHODS: BENEFIT was a randomized clinical trial comparing early versus...... delayed interferon beta-1b treatment in 465 patients with a CIS. Each patient provided a median of 14 (interquartile range = 13-16) spot urine samples throughout the 5-year follow-up. We estimated 24-hour urine sodium excretion level at each time point using the Tanaka equations, and assessed whether...... in T2 lesion volume: -0.11, 95% CI = -0.25 to 0.04; change in EDSS: -0.01, 95% CI = -0.09 to 0.08; relapse rate: HR = 0.78, 95% CI = 0.56-1.07). Results were similar in categorical analyses using quintiles. INTERPRETATION: Our results, based on multiple assessments of urine sodium excretion over 5...

  12. Immune activation in multiple sclerosis and interferon-beta therapy

    Krakauer, Martin

    2007-01-01

    The PhD dissertation emanated from the Danish MS Research Centre, Rigshosptalet, Copenhagen. Multiple sclerosis (MS) is an inflammatory disease of the CNS. Inflammatory responses by T helper (Th)-lymphocytes are characterised by distinct cytokine expression profiles. In MS, activated Th1...... of inflammation or secondary lymphatic organs. Chemokine receptors are differentially expressed in T cells in blood and cerebrospinal fluid, indicating their role for in T-cell-recruitment to the CNS. Interferon (IFN)-beta is a first-line treatment for MS. The mechanism of action is unclear, but probably includes...... changes in lymphocyte activation, cytokine secretion, and trafficking. The aim of the studies was to shed more light on T-cell immunology in MS and IFN-beta treatment, as well as identifying putative biomarkers of treatment response and/or disease activity. In one study we identified a Th-cell subset...

  13. Feature Selection, Flaring Size and Time-to-Flare Prediction Using Support Vector Regression, and Automated Prediction of Flaring Behavior Based on Spatio-Temporal Measures Using Hidden Markov Models

    Al-Ghraibah, Amani

    Solar flares release stored magnetic energy in the form of radiation and can have significant detrimental effects on earth including damage to technological infrastructure. Recent work has considered methods to predict future flare activity on the basis of quantitative measures of the solar magnetic field. Accurate advanced warning of solar flare occurrence is an area of increasing concern and much research is ongoing in this area. Our previous work 111] utilized standard pattern recognition and classification techniques to determine (classify) whether a region is expected to flare within a predictive time window, using a Relevance Vector Machine (RVM) classification method. We extracted 38 features which describing the complexity of the photospheric magnetic field, the result classification metrics will provide the baseline against which we compare our new work. We find a true positive rate (TPR) of 0.8, true negative rate (TNR) of 0.7, and true skill score (TSS) of 0.49. This dissertation proposes three basic topics; the first topic is an extension to our previous work [111, where we consider a feature selection method to determine an appropriate feature subset with cross validation classification based on a histogram analysis of selected features. Classification using the top five features resulting from this analysis yield better classification accuracies across a large unbalanced dataset. In particular, the feature subsets provide better discrimination of the many regions that flare where we find a TPR of 0.85, a TNR of 0.65 sightly lower than our previous work, and a TSS of 0.5 which has an improvement comparing with our previous work. In the second topic, we study the prediction of solar flare size and time-to-flare using support vector regression (SVR). When we consider flaring regions only, we find an average error in estimating flare size of approximately half a GOES class. When we additionally consider non-flaring regions, we find an increased average

  14. Study of Flare Assessment in Systemic Lupus Erythematosus Based on Paper Patients

    Isenberg, D; Sturgess, J; Allen, E

    2018-01-01

    OBJECTIVE: To determine the level of agreement of disease flare severity (distinguishing severe, moderate, and mild flare and persistent disease activity) in a large paper-patient exercise involving 988 individual cases of systemic lupus erythematosus. METHODS: A total of 988 individual lupus cas...

  15. Physical activity and pediatric multiple sclerosis: Developing a research agenda.

    Yeh, E Ann; Kinnett-Hopkins, Dominique; Grover, Stephanie A; Motl, Robert W

    2015-11-01

    Three-quarters of children with multiple sclerosis (MS) experience fatigue or depression, and progressive neurocognitive decline may be seen as early as two years after MS diagnosis. Furthermore, a higher magnetic resonance imaging disease burden is seen in pediatric-onset MS compared with adult-onset MS. To date, limited knowledge exists regarding behavioral methods for managing symptoms and disease progression in pediatric MS. To that end, this paper builds an evidence-based argument for the possible symptomatic and disease-modifying effects of exercise and physical activity in pediatric MS. This will be accomplished through: (a) a review of pediatric MS and its consequences; (b) a brief overview of physical activity and its consequences in children and adults with MS; and (c) a selective review of research on the neurological benefits of physical activity in pediatric populations. This topical review concludes with a list of 10 questions to guide future research on physical activity and pediatric MS. The objective of this paper is the provision of a research interest, focus and agenda involving pediatric MS and its lifelong management though exercise and physical activity behavior. Such an agenda is critical as the effects and maintenance of physical activity and exercise track across the lifespan, particularly when developed in the early stages of life. © The Author(s), 2015.

  16. Nitric oxide synthase expression and enzymatic activity in multiple sclerosis

    Broholm, H; Andersen, B; Wanscher, B

    2004-01-01

    We used post-mortem magnetic resonance imaging (MRI) guidance to obtain paired biopsies from the brains of four patients with clinical definite multiple sclerosis (MS). Samples were analyzed for the immunoreactivity (IR) of the three nitric oxide (NO) synthase isoforms [inducible, neuronal......NOS expressing cells in active lesions. NOS IR expressing cells were widely distributed in plaques, in white and gray matter that appeared normal macroscopically, and on MR. Endothelial NOS (eNOS) was highly expressed in intraparenchymal vascular endothelial cells of MS patients. A control group matched for age...

  17. Resource Constrained Planning of Multiple Projects with Separable Activities

    Fujii, Susumu; Morita, Hiroshi; Kanawa, Takuya

    In this study we consider a resource constrained planning problem of multiple projects with separable activities. This problem provides a plan to process the activities considering a resource availability with time window. We propose a solution algorithm based on the branch and bound method to obtain the optimal solution minimizing the completion time of all projects. We develop three methods for improvement of computational efficiency, that is, to obtain initial solution with minimum slack time rule, to estimate lower bound considering both time and resource constraints and to introduce an equivalence relation for bounding operation. The effectiveness of the proposed methods is demonstrated by numerical examples. Especially as the number of planning projects increases, the average computational time and the number of searched nodes are reduced.

  18. PREDICTION OF SOLAR FLARES USING UNIQUE SIGNATURES OF MAGNETIC FIELD IMAGES

    Raboonik, Abbas; Safari, Hossein; Alipour, Nasibe [Department of Physics, University of Zanjan, P.O. Box 45195-313, Zanjan (Iran, Islamic Republic of); Wheatland, Michael S., E-mail: raboonik@alumni.znu.ac.ir, E-mail: safari@znu.ac.ir [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)

    2017-01-01

    Prediction of solar flares is an important task in solar physics. The occurrence of solar flares is highly dependent on the structure and topology of solar magnetic fields. A new method for predicting large (M- and X-class) flares is presented, which uses machine learning methods applied to the Zernike moments (ZM) of magnetograms observed by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory for a period of six years from 2010 June 2 to 2016 August 1. Magnetic field images consisting of the radial component of the magnetic field are converted to finite sets of ZMs and fed to the support vector machine classifier. ZMs have the capability to elicit unique features from any 2D image, which may allow more accurate classification. The results indicate whether an arbitrary active region has the potential to produce at least one large flare. We show that the majority of large flares can be predicted within 48 hr before their occurrence, with only 10 false negatives out of 385 flaring active region magnetograms and 21 false positives out of 179 non-flaring active region magnetograms. Our method may provide a useful tool for the prediction of solar flares, which can be employed alongside other forecasting methods.

  19. Multiple Activities of Punica granatum Linne against Acne Vulgaris.

    Lee, Chia-Jung; Chen, Lih-Geeng; Liang, Wen-Li; Wang, Ching-Chiung

    2017-01-12

    Acne is a common skin condition with sebum overproduction, hyperkeratosis, Propionibacterium acnes ( P . acnes ) and Staphylococcus aureus , and inflammation. Punica granatum (pomegranate) is well-known for its anti-inflammatory effects; however, few studies have discussed the anti-acne effects of pomegranate. In this study, we found that pomegranate extract (PG-E) significantly reduced P . acnes -induced edema in Wistar rat ears. Therefore, an evaluation platform using multiple pathogenic mechanisms of acne was established to explore the anti-acne effects of pomegranate. Results showed that PG-E inhibited bacterial growth and lipase activity. Through a bioguided-fractionation-isolation system, four hydrolysable tannins, punicalagin ( 1 ), punicalin ( 2 ), strictinin A ( 3 ), and granatin B ( 4 ), were isolated. Compounds 1 and 2 had greater anti-bacterial activities and anti-testosterone-induced HaCaT proliferative effects than the others. Compounds 1 , 3 , and 4 displayed lipase inhibitory effects. Compound 4 decreased cyclooxygenase-2 expression and downregulated prostaglandin E₂ production in heat-killed P . acnes -treated RAW 246.7 cells. In conclusion, PG-E is abundant in hydrolysable tannins that display multiple anti-acne capacities, including anti-bacterial, anti-lipase, anti-keratinocyte proliferation, and anti-inflammatory actions. Hence, PG-E has great potential in the application of anti-acne and skin-care products, and punicalagin ( 1 ), the most effective component in PG-E, can be employed as a quality control marker.

  20. Well-observed dynamics of flaring and peripheral coronal magnetic loops during an M-class limb flare

    Shen, Jinhua; Zhou, Tuanhui; Ji, Haisheng; Feng, Li; Wiegelmann, Thomas; Inhester, Bernd

    2014-01-01

    In this paper, we present a variety of well-observed dynamic behaviors for the flaring and peripheral magnetic loops of the M6.6 class extreme limb flare that occurred on 2011 February 24 (SOL2011-02-24T07:20) from EUV observations by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory and X-ray observations by RHESSI. The flaring loop motion confirms the earlier contraction-expansion picture. We find that the U-shaped trajectory delineated by the X-ray corona source of the flare roughly follows the direction of a filament eruption associated with the flare. Different temperature structures of the coronal source during the contraction and expansion phases strongly suggest different kinds of magnetic reconnection processes. For some peripheral loops, we discover that their dynamics are closely correlated with the filament eruption. During the slow rising to abrupt, fast rising of the filament, overlying peripheral magnetic loops display different responses. Two magnetic loops on the elbow of the active region had a slow descending motion followed by an abrupt successive fast contraction, while magnetic loops on the top of the filament were pushed outward, slowly being inflated for a while and then erupting as a moving front. We show that the filament activation and eruption play a dominant role in determining the dynamics of the overlying peripheral coronal magnetic loops.

  1. Statistical properties of solar flares and coronal mass ejections through the solar cycle

    Telloni, Daniele; Antonucci, Ester; Carbone, Vincenzo; Lepreti, Fabio

    2016-01-01

    Waiting Time Distributions (WTDs) of solar flares are investigated all through the solar cycle. The same approach applied to Coronal Mass Ejections (CMEs) in a previous work is considered here for flare occurrence. Our analysis reveals that flares and CMEs share some common statistical properties, which result dependent on the level of solar activity. Both flares and CMEs seem to independently occur during minimum solar activity phases, whilst their WTDs significantly deviate from a Poisson function at solar maximum, thus suggesting that these events are correlated. The characteristics of WTDs are constrained by the physical processes generating those eruptions associated with flares and CMEs. A scenario may be drawn in which different mechanisms are actively at work during different phases of the solar cycle. Stochastic processes, most likely related to random magnetic reconnections of the field lines, seem to play a key role during solar minimum periods. On the other hand, persistent processes, like sympathetic eruptions associated to the variability of the photospheric magnetism, are suggested to dominate during periods of high solar activity. Moreover, despite the similar statistical properties shown by flares and CMEs, as it was mentioned above, their WTDs appear different in some aspects. During solar minimum periods, the flare occurrence randomness seems to be more evident than for CMEs. Those persistent mechanisms generating interdependent events during maximum periods of solar activity can be suggested to play a more important role for CMEs than for flares, thus mitigating the competitive action of the random processes, which seem instead strong enough to weaken the correlations among flare event occurrence during solar minimum periods. However, it cannot be excluded that the physical processes at the basis of the origin of the temporal correlation between solar events are different for flares and CMEs, or that, more likely, more sophisticated effects are

  2. What's an Asthma Flare-Up?

    ... Staying Safe Videos for Educators Search English Español Asthma Flare-Ups KidsHealth / For Parents / Asthma Flare-Ups ... español ¿Qué es una crisis asmática? What Are Asthma Flare-Ups? Keeping asthma under control helps kids ...

  3. Instant CloudFlare starter

    Dickey, Jeff

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. Written as a practical guide, CloudFlare Starter will show you all you need to know in order to effectively improve your online presence in a multitude of different ways. ""Instant CloudFlare Starter"" is a practical yet accessible guide for website owners looking to optimize their site for optimum security and maximum performance.

  4. Predicting and preventing the future: actively managing multiple sclerosis.

    Hutchinson, Michael

    2012-02-01

    Relapsing-remitting multiple sclerosis (MS) has a highly variable clinical course but a number of demographic, clinical and MRI features can guide the clinician in the assessment of disease activity and likely disability outcome. It is also clear that the inflammatory activity in the first five years of relapsing-remitting MS results in the neurodegenerative changes seen in secondary progressive MS 10-15 years later. While conventional first-line disease modifying therapy has an effect on relapses, about one third of patients have a suboptimal response to treatment. With the advent of highly active second-line therapies with their evident marked suppression of inflammation, the clinician now has the tools to manage the course of relapsing-remitting MS more effectively. The development of treatment optimisation recommendations based on the clinical response to first-line therapies can guide the neurologist in more active management of the early course of relapsing-remitting MS, with the aim of preventing both acute inflammatory axonal injury and the neurodegenerative process which leads to secondary progressive MS.

  5. International consensus for a definition of disease flare in lupus.

    Ruperto, N; Hanrahan, L M; Alarcón, G S; Belmont, H M; Brey, R L; Brunetta, P; Buyon, J P; Costner, M I; Cronin, M E; Dooley, M A; Filocamo, G; Fiorentino, D; Fortin, P R; Franks, A G; Gilkeson, G; Ginzler, E; Gordon, C; Grossman, J; Hahn, B; Isenberg, D A; Kalunian, K C; Petri, M; Sammaritano, L; Sánchez-Guerrero, J; Sontheimer, R D; Strand, V; Urowitz, M; von Feldt, J M; Werth, V P; Merrill, J T

    2011-04-01

    The Lupus Foundation of America (LFA) convened an international working group to obtain a consensus definition of disease flare in lupus. With help from the Paediatric Rheumatology International Trials Organization (PRINTO), two web-based Delphi surveys of physicians were conducted. Subsequently, the LFA held a second consensus conference followed by a third Delphi survey to reach a community-wide agreement for flare definition. Sixty-nine of the 120 (57.5%) polled physicians responded to the first survey. Fifty-nine of the responses were available to draft 12 preliminary statements, which were circulated in the second survey. Eighty-seven of 118 (74%) physicians completed the second survey, with an agreement of 70% for 9/12 (75%) statements. During the second conference, three alternative flare definitions were consolidated and sent back to the international community. One hundred and sixteen of 146 (79.5%) responded, with agreement by 71/116 (61%) for the following definition: "A flare is a measurable increase in disease activity in one or more organ systems involving new or worse clinical signs and symptoms and/or laboratory measurements. It must be considered clinically significant by the assessor and usually there would be at least consideration of a change or an increase in treatment." The LFA proposes this definition for lupus flare on the basis of its high face validity.

  6. CHROMOSPHERIC EVAPORATION IN AN M1.8 FLARE OBSERVED BY THE EXTREME-ULTRAVIOLET IMAGING SPECTROMETER ON HINODE

    Doschek, G. A.; Warren, H. P.; Young, P. R.

    2013-01-01

    We discuss observations of chromospheric evaporation for a complex flare that occurred on 2012 March 9 near 03:30 UT obtained from the Extreme-ultraviolet Imaging Spectrometer (EIS) on board the Hinode spacecraft. This was a multiple event with a strong energy input that reached the M1.8 class when observed by EIS. EIS was in raster mode and fortunately the slit was almost at the exact location of a significant energy input. Also, EIS obtained a full-CCD spectrum of the flare, i.e., the entire CCD was readout so that data were obtained for about the 500 lines identified in the EIS wavelength ranges. Chromospheric evaporation characterized by 150-200 km s –1 upflows was observed in multiple locations in multi-million degree spectral lines of flare ions such as Fe XXII, Fe XXIII, and Fe XXIV, with simultaneous 20-60 km s –1 upflows in million degree coronal lines from ions such as Fe XII-Fe XVI. The behavior of cooler, transition region ions such as O VI, Fe VIII, He II, and Fe X is more complex, but upflows were also observed in Fe VIII and Fe X lines. At a point close to strong energy input in space and time, the flare ions Fe XXII, Fe XXIII, and Fe XXIV reveal an isothermal source with a temperature close to 14 MK and no strong blueshifted components. At this location there is a strong downflow in cooler active region lines from ions such as Fe XIII and Fe XIV, on the order of 200 km s –1 . We speculate that this downflow may be evidence of the downward shock produced by reconnection in the current sheet seen in MHD simulations. A sunquake also occurred near this location. Electron densities were obtained from density sensitive lines ratios from Fe XIII and Fe XIV. Atmospheric Imaging Assembly (AIA) observations from the Solar Dynamics Observatory are used with JHelioviewer to obtain a qualitative overview of the flare. However, AIA data are not presented in this paper. In summary, spectroscopic data from EIS are presented that can be used for predictive

  7. Chromospheric Evaporation in an M1.8 Flare Observed by the Extreme-ultraviolet Imaging Spectrometer on Hinode

    Doschek, G. A.; Warren, H. P.; Young, P. R.

    2013-04-01

    We discuss observations of chromospheric evaporation for a complex flare that occurred on 2012 March 9 near 03:30 UT obtained from the Extreme-ultraviolet Imaging Spectrometer (EIS) on board the Hinode spacecraft. This was a multiple event with a strong energy input that reached the M1.8 class when observed by EIS. EIS was in raster mode and fortunately the slit was almost at the exact location of a significant energy input. Also, EIS obtained a full-CCD spectrum of the flare, i.e., the entire CCD was readout so that data were obtained for about the 500 lines identified in the EIS wavelength ranges. Chromospheric evaporation characterized by 150-200 km s-1 upflows was observed in multiple locations in multi-million degree spectral lines of flare ions such as Fe XXII, Fe XXIII, and Fe XXIV, with simultaneous 20-60 km s-1 upflows in million degree coronal lines from ions such as Fe XII-Fe XVI. The behavior of cooler, transition region ions such as O VI, Fe VIII, He II, and Fe X is more complex, but upflows were also observed in Fe VIII and Fe X lines. At a point close to strong energy input in space and time, the flare ions Fe XXII, Fe XXIII, and Fe XXIV reveal an isothermal source with a temperature close to 14 MK and no strong blueshifted components. At this location there is a strong downflow in cooler active region lines from ions such as Fe XIII and Fe XIV, on the order of 200 km s-1. We speculate that this downflow may be evidence of the downward shock produced by reconnection in the current sheet seen in MHD simulations. A sunquake also occurred near this location. Electron densities were obtained from density sensitive lines ratios from Fe XIII and Fe XIV. Atmospheric Imaging Assembly (AIA) observations from the Solar Dynamics Observatory are used with JHelioviewer to obtain a qualitative overview of the flare. However, AIA data are not presented in this paper. In summary, spectroscopic data from EIS are presented that can be used for predictive tests of

  8. Reconnection Fluxes in Eruptive and Confined Flares and Implications for Superflares on the Sun

    Tschernitz, Johannes; Veronig, Astrid M.; Thalmann, Julia K.; Hinterreiter, Jürgen; Pötzi, Werner

    2018-01-01

    We study the energy release process of a set of 51 flares (32 confined, 19 eruptive) ranging from GOES class B3 to X17. We use Hα filtergrams from Kanzelhöhe Observatory together with Solar Dynamics Observatory HMI and Solar and Heliospheric Observatory MDI magnetograms to derive magnetic reconnection fluxes and rates. The flare reconnection flux is strongly correlated with the peak of the GOES 1–8 Å soft X-ray flux (c = 0.92, in log–log space) for both confined and eruptive flares. Confined flares of a certain GOES class exhibit smaller ribbon areas but larger magnetic flux densities in the flare ribbons (by a factor of 2). In the largest events, up to ≈50% of the magnetic flux of the active region (AR) causing the flare is involved in the flare magnetic reconnection. These findings allow us to extrapolate toward the largest solar flares possible. A complex solar AR hosting a magnetic flux of 2 × 1023 Mx, which is in line with the largest AR fluxes directly measured, is capable of producing an X80 flare, which corresponds to a bolometric energy of about 7 × 1032 erg. Using a magnetic flux estimate of 6 × 1023 Mx for the largest solar AR observed, we find that flares of GOES class ≈X500 could be produced (E bol ≈ 3 × 1033 erg). These estimates suggest that the present day’s Sun is capable of producing flares and related space weather events that may be more than an order of magnitude stronger than have been observed to date.

  9. On the distribution of the frequency of stellar flares in stellar aggregates

    Mnatsakanyan, M.A.

    1986-01-01

    The analytic time-representation of the multiplicity of flares in stellar aggregates based on observational data at present is given under the condition of independency of flares from each other. They are exactly approximated by two ''Poisson'' groups with stars in each of them having the same frequency: N 1 =670, ν 1 =1.1 flares at all observational time, N 2 =60, ν 2 =9 - for Pleiades, and by one Poisson process with N=1250, ν=0.49 - for Orion, N=330, ν=0.37 - for the Dark Nebulae of Taurus. The total number of fkare stars in the Pleiades is nearly equal or less than 750

  10. THE 2010 VERY HIGH ENERGY {gamma}-RAY FLARE AND 10 YEARS OF MULTI-WAVELENGTH OBSERVATIONS OF M 87

    Abramowski, A. [Institut fuer Experimentalphysik, Universitaet Hamburg, Luruper Chaussee 149, D 22761 Hamburg (Germany); Acero, F. [Laboratoire Univers et Particules de Montpellier, Universite Montpellier 2, CNRS/IN2P3, CC 72, Place Eugene Bataillon, F-34095 Montpellier Cedex 5 (France); Aharonian, F.; Bernloehr, K.; Bochow, A. [Max-Planck-Institut fuer Kernphysik, P.O. Box 103980, D 69029 Heidelberg (Germany); Akhperjanian, A. G. [National Academy of Sciences of the Republic of Armenia, 24 Marshall Baghramian Avenue, 0019 Yerevan (Armenia); Anton, G.; Balzer, A. [Physikalisches Institut, Universitaet Erlangen-Nuernberg, Erwin-Rommel-Str. 1, D 91058 Erlangen (Germany); Barnacka, A. [Nicolaus Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warsaw (Poland); Barres de Almeida, U. [Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Becherini, Y. [Astroparticule et Cosmologie (APC), CNRS, Universite Paris 7 Denis Diderot, 10, rue Alice Domon et Leonie Duquet, F-75205 Paris Cedex 13 (France); Becker, J. [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum und Astrophysik, Ruhr-Universitaet Bochum, D 44780 Bochum (Germany); Behera, B. [Landessternwarte, Universitaet Heidelberg, Koenigstuhl, D 69117 Heidelberg (Germany); Birsin, E. [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstr. 15, D 12489 Berlin (Germany); Biteau, J. [Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); Boisson, C. [LUTH, Observatoire de Paris, CNRS, Universite Paris Diderot, 5 Place Jules Janssen, 92190 Meudon (France); Bolmont, J. [LPNHE, Universite Pierre et Marie Curie Paris 6, Universite Denis Diderot Paris 7, CNRS/IN2P3, 4 Place Jussieu, F-75252, Paris Cedex 5 (France); Bordas, P., E-mail: martin.raue@desy.de [Institut fuer Astronomie und Astrophysik, Universitaet Tuebingen, Sand 1, D 72076 Tuebingen (Germany); Collaboration: H.E.S.S. Collaboration; MAGIC Collaboration; VERITAS Collaboration; and others

    2012-02-20

    The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3 - 6) Multiplication-Sign 10{sup 9} M{sub Sun }) provides a unique opportunity to investigate the origin of very high energy (VHE; E > 100 GeV) {gamma}-ray emission generated in relativistic outflows and the surroundings of supermassive black holes. M 87 has been established as a VHE {gamma}-ray emitter since 2006. The VHE {gamma}-ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M 87 by the MAGIC and VERITAS instruments in 2010 are reported. During the campaign, a flare at VHE was detected triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and radio (43 GHz Very Long Baseline Array, VLBA). The excellent sampling of the VHE {gamma}-ray light curve enables one to derive a precise temporal characterization of the flare: the single, isolated flare is well described by a two-sided exponential function with significantly different flux rise and decay times of {tau}{sup rise}{sub d} = (1.69 {+-} 0.30) days and {tau}{sup decay}{sub d} = (0.611 {+-} 0.080) days, respectively. While the overall variability pattern of the 2010 flare appears somewhat different from that of previous VHE flares in 2005 and 2008, they share very similar timescales ({approx}day), peak fluxes ({Phi}{sub >0.35TeV} {approx_equal} (1-3) Multiplication-Sign 10{sup -11} photons cm{sup -2} s{sup -1}), and VHE spectra. VLBA radio observations of 43 GHz of the inner jet regions indicate no enhanced flux in 2010 in contrast to observations in 2008, where an increase of the radio flux of the innermost core regions coincided with a VHE flare. On the other hand, Chandra X-ray observations taken {approx}3 days after the peak of the VHE {gamma}-ray emission reveal an enhanced flux from the core (flux increased by factor {approx}2; variability timescale <2 days). The long-term (2001-2010) multi-wavelength (MWL

  11. Energy Release in Solar Flares,

    1982-10-01

    Plasma Research, Stanford University P. Kaufmanu CRAA/CNPq -Conseiho lacional de Desenvolvimento Cientifico e Tecnologico, Slo Paulo, SP, Brasil D.F...three phases of energy release in solar flares (Sturrock, 1980). However, a recent article by Feldman e a.. (1982) points to a significant

  12. Thermal Fronts in Solar Flares

    Karlický, Marian

    2015-01-01

    Roč. 814, č. 2 (2015), 153/1-153/7 ISSN 0004-637X R&D Projects: GA ČR GAP209/12/0103 Institutional support: RVO:67985815 Keywords : plasmas * Sun flares * radio radiation Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.909, year: 2015

  13. HOOKED FLARE RIBBONS AND FLUX-ROPE-RELATED QSL FOOTPRINTS

    Zhao, Jie; Li, Hui [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, CAS, Nanjing 210008 (China); Gilchrist, Stuart A.; Aulanier, Guillaume; Schmieder, Brigitte; Pariat, Etienne, E-mail: nj.lihui@pmo.ac.cn [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris-Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France)

    2016-05-20

    We studied the magnetic topology of active region 12158 on 2014 September 10 and compared it with the observations before and early in the flare that begins at 17:21 UT (SOL2014-09-10T17:45:00). Our results show that the sigmoidal structure and flare ribbons of this active region observed by the Solar Dynamics Observatory /Atmospheric Imaging Assembly can be well reproduced from a Grad–Rubin nonlinear force-free field extrapolation method. Various inverse-S- and inverse-J-shaped magnetic field lines, which surround a coronal flux rope, coincide with the sigmoid as observed in different extreme-ultraviolet wavelengths, including its multithreaded curved ends. Also, the observed distribution of surface currents in the magnetic polarity where it was not prescribed is well reproduced. This validates our numerical implementation and setup of the Grad–Rubin method. The modeled double inverse-J-shaped quasi-separatrix layer (QSL) footprints match the observed flare ribbons during the rising phase of the flare, including their hooked parts. The spiral-like shape of the latter may be related to a complex pre-eruptive flux rope with more than one turn of twist, as obtained in the model. These ribbon-associated flux-rope QSL footprints are consistent with the new standard flare model in 3D, with the presence of a hyperbolic flux tube located below an inverse-teardrop-shaped coronal QSL. This is a new step forward forecasting the locations of reconnection and ribbons in solar flares and the geometrical properties of eruptive flux ropes.

  14. HOOKED FLARE RIBBONS AND FLUX-ROPE-RELATED QSL FOOTPRINTS

    Zhao, Jie; Li, Hui; Gilchrist, Stuart A.; Aulanier, Guillaume; Schmieder, Brigitte; Pariat, Etienne

    2016-01-01

    We studied the magnetic topology of active region 12158 on 2014 September 10 and compared it with the observations before and early in the flare that begins at 17:21 UT (SOL2014-09-10T17:45:00). Our results show that the sigmoidal structure and flare ribbons of this active region observed by the Solar Dynamics Observatory /Atmospheric Imaging Assembly can be well reproduced from a Grad–Rubin nonlinear force-free field extrapolation method. Various inverse-S- and inverse-J-shaped magnetic field lines, which surround a coronal flux rope, coincide with the sigmoid as observed in different extreme-ultraviolet wavelengths, including its multithreaded curved ends. Also, the observed distribution of surface currents in the magnetic polarity where it was not prescribed is well reproduced. This validates our numerical implementation and setup of the Grad–Rubin method. The modeled double inverse-J-shaped quasi-separatrix layer (QSL) footprints match the observed flare ribbons during the rising phase of the flare, including their hooked parts. The spiral-like shape of the latter may be related to a complex pre-eruptive flux rope with more than one turn of twist, as obtained in the model. These ribbon-associated flux-rope QSL footprints are consistent with the new standard flare model in 3D, with the presence of a hyperbolic flux tube located below an inverse-teardrop-shaped coronal QSL. This is a new step forward forecasting the locations of reconnection and ribbons in solar flares and the geometrical properties of eruptive flux ropes.

  15. Flare observation by the satellite 'Hinotori'

    Tanaka, Toshio

    1981-01-01

    The satellite ''Hinotori'' makes 5 rounds a day and is doing flare observation. The total observation days amounted to 94 days. Among the observed flares, the quiet mode flares were picked up from the reproduced data. The plot of the time variation of flares was obtained for four energy bands, HXM-1 (17 to 40 keV), HXM2 - 7 (over 40 keV), FLM-L (1 to 5 keV) and FLM-H (5 to 12 keV). At present, the judge of flares is made by using hard X-ray of the HXM-1 plot. False signals were completely removed. A large percentage of big flares was collected by Hinotori, eleven X-class flares were recorded. The operation status of ''Hinotori'' has been in good condition. The spin frequency has increased with a constant rate. (Kato, T.)

  16. Solar flares: invited review at the Royal Astronomical Society's meeting at Armagh, April 5, 1991

    Phillips, K.J.H.

    1991-04-01

    A solar flare may be defined to be the sudden release of stored magnetic energy in an active region and all the associated radiation, particle, mass-motion, wave and shock-wave phenomena directly resulting from it or triggered by it. In the last few years, solar flares have taken on an extra significance in respect of the fact that outbursts on cool dwarf stars seem to have the same characteristics and are widely assumed to be the same type of phenomenon. The physical mechanism that leads to solar flares, most likely the reconnection of magnetic fields, may well be the one that operates in stellar flares also. In this review, I shall deal with the chief observational facts about flares and associated phenomena, then deal with both interpretations and magnetic field reconnection theories. (Author)

  17. Natural gas domestic market development for total elimination of routine flares in Nigeria's upstream petroleum operations

    Sonibare, J.A.; Akeredolu, F.A.

    2006-01-01

    Several research findings confirmed that gaseous emissions and thermal radiation emanate from flaring activities during separation of oil from gas in the petroleum upstream operations. This, coupled with identified degradation potential of flares, makes flaring of about 71 million m 3 /day of associated gas a great concern. In this paper, several efforts hitherto made by government and organized private sectors at monetizing associated natural gas being flared on daily basis in Nigeria were reviewed. Domestic market development, if adopted, could eliminate routine gas flaring by 2008, meeting a goal set by Nigerian Government. Various scenarios considered showed that relatively minor amounts of natural gas could be consumed domestically for cooking; the balance would be absorbed by thermal electricity generation. It could lead to total consumption of between 92 and 140 million m 3 /day of natural gas in the country, representing a fraction of the domestic energy market

  18. Observations of solar flare transition zone plasmas from the Solar Maximum Mission

    Cheng, C.-C.; Bruner, E. C.; Tandberg-Hanssen, E.; Woodgate, B. E.; Shine, R. A.; Kenny, P. J.; Henze, W.; Poletto, G.

    1982-01-01

    The spatial and temporal evolution of the Si IV and O IV intensity, density and mass motions in preflare and flare transition zone plasmas are studied for the case of the April 8, 1980 flare. It is found that: (1) the UV flare observed in the Si IV and O IV lines is unambiguously identified as occurring in a low-lying, preexisting transition zone loop which spanned the magnetic neutral line separating a larger leader spot and a newly emerged, isolated spot of opposite polarity; (2) at the onset of the flare, the easternmost footpoint, which was anchored in an isolated spot region of high longitudinal magnetic field gradient, showed sudden, impulsive brightening with large intensity increases; and (3) the release flare energy was transported by way of large-scale connecting field lines to other parts of the active region, producing the hot plasma and H-alpha kernels observed near the trailing spot.

  19. Center-to-Limb Variability of Hot Coronal EUV Emissions During Solar Flares

    Thiemann, E. M. B.; Chamberlin, P. C.; Eparvier, F. G.; Epp, L.

    2018-02-01

    It is generally accepted that densities of quiet-Sun and active region plasma are sufficiently low to justify the optically thin approximation, and this is commonly used in the analysis of line emissions from plasma in the solar corona. However, the densities of solar flare loops are substantially higher, compromising the optically thin approximation. This study begins with a radiative transfer model that uses typical solar flare densities and geometries to show that hot coronal emission lines are not generally optically thin. Furthermore, the model demonstrates that the observed line intensity should exhibit center-to-limb variability (CTLV), with flares observed near the limb being dimmer than those occurring near disk center. The model predictions are validated with an analysis of over 200 flares observed by the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO), which uses six lines, with peak formation temperatures between 8.9 and 15.8 MK, to show that limb flares are systematically dimmer than disk-center flares. The data are then used to show that the electron column density along the line of sight typically increases by 1.76 × 10^{19} cm^{-2} for limb flares over the disk-center flare value. It is shown that the CTLV of hot coronal emissions reduces the amount of ionizing radiation propagating into the solar system, and it changes the relative intensities of lines and bands commonly used for spectral analysis.

  20. Differential rotation, flares and coronae in A to M stars

    Balona, L. A.; Švanda, Michal; Karlický, Marian

    2016-01-01

    Roč. 463, č. 2 (2016), s. 1740-1750 ISSN 0035-8711 R&D Projects: GA ČR GAP209/12/0103 Grant - others:GA ČR(CZ) GA15-02112S Institutional support: RVO:67985815 Keywords : stars * activity * flare Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.961, year: 2016

  1. Mouse visual neocortex supports multiple stereotyped patterns of microcircuit activity.

    Sadovsky, Alexander J; MacLean, Jason N

    2014-06-04

    Spiking correlations between neocortical neurons provide insight into the underlying synaptic connectivity that defines cortical microcircuitry. Here, using two-photon calcium fluorescence imaging, we observed the simultaneous dynamics of hundreds of neurons in slices of mouse primary visual cortex (V1). Consistent with a balance of excitation and inhibition, V1 dynamics were characterized by a linear scaling between firing rate and circuit size. Using lagged firing correlations between neurons, we generated functional wiring diagrams to evaluate the topological features of V1 microcircuitry. We found that circuit connectivity exhibited both cyclic graph motifs, indicating recurrent wiring, and acyclic graph motifs, indicating feedforward wiring. After overlaying the functional wiring diagrams onto the imaged field of view, we found properties consistent with Rentian scaling: wiring diagrams were topologically efficient because they minimized wiring with a modular architecture. Within single imaged fields of view, V1 contained multiple discrete circuits that were overlapping and highly interdigitated but were still distinct from one another. The majority of neurons that were shared between circuits displayed peri-event spiking activity whose timing was specific to the active circuit, whereas spike times for a smaller percentage of neurons were invariant to circuit identity. These data provide evidence that V1 microcircuitry exhibits balanced dynamics, is efficiently arranged in anatomical space, and is capable of supporting a diversity of multineuron spike firing patterns from overlapping sets of neurons. Copyright © 2014 the authors 0270-6474/14/347769-09$15.00/0.

  2. THERMODYNAMIC SPECTRUM OF SOLAR FLARES BASED ON SDO/EVE OBSERVATIONS: TECHNIQUES AND FIRST RESULTS

    Wang, Yuming; Zhou, Zhenjun; Liu, Kai; Liu, Rui; Shen, Chenglong [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Jie [School of Physics, Astronomy and Computational Sciences, George Mason University, 4400 University Drive, MSN 6A2, Fairfax, VA 22030 (United States); Chamberlin, Phillip C., E-mail: ymwang@ustc.edu.cn [Solar Physics Laboratory, Heliophysics Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-03-15

    The Solar Dynamics Observatory (SDO)/EUV Variability Experiment (EVE) provides rich information on the thermodynamic processes of solar activities, particularly on solar flares. Here, we develop a method to construct thermodynamic spectrum (TDS) charts based on the EVE spectral lines. This tool could potentially be useful for extreme ultraviolet (EUV) astronomy to learn about the eruptive activities on distant astronomical objects. Through several cases, we illustrate what we can learn from the TDS charts. Furthermore, we apply the TDS method to 74 flares equal to or greater than the M5.0 class, and reach the following statistical results. First, EUV peaks are always behind the soft X-ray (SXR) peaks and stronger flares tend to have faster cooling rates. There is a power-law correlation between the peak delay times and the cooling rates, suggesting a coherent cooling process of flares from SXR to EUV emissions. Second, there are two distinct temperature drift patterns, called Type I and Type II. For Type I flares, the enhanced emission drifts from high to low temperature like a quadrilateral, whereas for Type II flares the drift pattern looks like a triangle. Statistical analysis suggests that Type II flares are more impulsive than Type I flares. Third, for late-phase flares, the peak intensity ratio of the late phase to the main phase is roughly correlated with the flare class, and the flares with a strong late phase are all confined. We believe that the re-deposition of the energy carried by a flux rope, which unsuccessfully erupts out, into thermal emissions is responsible for the strong late phase found in a confined flare. Furthermore, we show the signatures of the flare thermodynamic process in the chromosphere and transition region in the TDS charts. These results provide new clues to advance our understanding of the thermodynamic processes of solar flares and associated solar eruptions, e.g., coronal mass ejections.

  3. THE NATURE OF CME-FLARE-ASSOCIATED CORONAL DIMMING

    Cheng, J. X. [Key Laboratory of Planetary Sciences, Shanghai Astronomical Observatory, Shanghai 200030 (China); Qiu, J., E-mail: chengjx@shao.ac.cn [Department of Physics, Montana State University, Bozeman MT 59717-3840 (United States)

    2016-07-01

    Coronal mass ejections (CMEs) are often accompanied by coronal dimming that is evident in extreme ultraviolet (EUV) and soft X-ray observations. The locations of dimming are sometimes considered to map footpoints of the erupting flux rope. As the emitting material expands in the corona, the decreased plasma density leads to reduced emission observed in spectral and irradiance measurements. Therefore, signatures of dimming may reflect the properties of CMEs in the early phase of their eruption. In this study, we analyze the event of flare, CME, and coronal dimming on 2011 December 26. We use the data from the Atmospheric Imaging Assembly on the Solar Dynamics Observatory for disk observations of the dimming, and analyze images taken by EUVI, COR1, and COR2 on board the Solar Terrestrial Relations Observatory to obtain the height and velocity of the associated CMEs observed at the limb. We also measure the magnetic reconnection rate from flare observations. Dimming occurs in a few locations next to the flare ribbons, and it is observed in multiple EUV passbands. Rapid dimming starts after the onset of fast reconnection and CME acceleration, and its evolution tracks the CME height and flare reconnection. The spatial distribution of dimming exhibits cores of deep dimming with a rapid growth, and their light curves are approximately linearly scaled with the CME height profile. From the dimming analysis we infer the process of the CME expansion, and estimate properties of the CME.

  4. LONG DURATION FLARE EMISSION: IMPULSIVE HEATING OR GRADUAL HEATING?

    Qiu, Jiong; Longcope, Dana W. [Department of Physics, Montana State University, Bozeman MT 59717-3840 (United States)

    2016-03-20

    Flare emissions in X-ray and EUV wavelengths have previously been modeled as the plasma response to impulsive heating from magnetic reconnection. Some flares exhibit gradually evolving X-ray and EUV light curves, which are believed to result from superposition of an extended sequence of impulsive heating events occurring in different adjacent loops or even unresolved threads within each loop. In this paper, we apply this approach to a long duration two-ribbon flare SOL2011-09-13T22 observed by the Atmosphere Imaging Assembly (AIA). We find that to reconcile with observed signatures of flare emission in multiple EUV wavelengths, each thread should be heated in two phases, an intense impulsive heating followed by a gradual, low-rate heating tail that is attenuated over 20–30 minutes. Each AIA resolved single loop may be composed of several such threads. The two-phase heating scenario is supported by modeling with both a zero-dimensional and a 1D hydrodynamic code. We discuss viable physical mechanisms for the two-phase heating in a post-reconnection thread.

  5. THE NATURE OF CME-FLARE-ASSOCIATED CORONAL DIMMING

    Cheng, J. X.; Qiu, J.

    2016-01-01

    Coronal mass ejections (CMEs) are often accompanied by coronal dimming that is evident in extreme ultraviolet (EUV) and soft X-ray observations. The locations of dimming are sometimes considered to map footpoints of the erupting flux rope. As the emitting material expands in the corona, the decreased plasma density leads to reduced emission observed in spectral and irradiance measurements. Therefore, signatures of dimming may reflect the properties of CMEs in the early phase of their eruption. In this study, we analyze the event of flare, CME, and coronal dimming on 2011 December 26. We use the data from the Atmospheric Imaging Assembly on the Solar Dynamics Observatory for disk observations of the dimming, and analyze images taken by EUVI, COR1, and COR2 on board the Solar Terrestrial Relations Observatory to obtain the height and velocity of the associated CMEs observed at the limb. We also measure the magnetic reconnection rate from flare observations. Dimming occurs in a few locations next to the flare ribbons, and it is observed in multiple EUV passbands. Rapid dimming starts after the onset of fast reconnection and CME acceleration, and its evolution tracks the CME height and flare reconnection. The spatial distribution of dimming exhibits cores of deep dimming with a rapid growth, and their light curves are approximately linearly scaled with the CME height profile. From the dimming analysis we infer the process of the CME expansion, and estimate properties of the CME.

  6. Multiplicative point process as a model of trading activity

    Gontis, V.; Kaulakys, B.

    2004-11-01

    Signals consisting of a sequence of pulses show that inherent origin of the 1/ f noise is a Brownian fluctuation of the average interevent time between subsequent pulses of the pulse sequence. In this paper, we generalize the model of interevent time to reproduce a variety of self-affine time series exhibiting power spectral density S( f) scaling as a power of the frequency f. Furthermore, we analyze the relation between the power-law correlations and the origin of the power-law probability distribution of the signal intensity. We introduce a stochastic multiplicative model for the time intervals between point events and analyze the statistical properties of the signal analytically and numerically. Such model system exhibits power-law spectral density S( f)∼1/ fβ for various values of β, including β= {1}/{2}, 1 and {3}/{2}. Explicit expressions for the power spectra in the low-frequency limit and for the distribution density of the interevent time are obtained. The counting statistics of the events is analyzed analytically and numerically, as well. The specific interest of our analysis is related with the financial markets, where long-range correlations of price fluctuations largely depend on the number of transactions. We analyze the spectral density and counting statistics of the number of transactions. The model reproduces spectral properties of the real markets and explains the mechanism of power-law distribution of trading activity. The study provides evidence that the statistical properties of the financial markets are enclosed in the statistics of the time interval between trades. A multiplicative point process serves as a consistent model generating this statistics.

  7. Predicting Solar Flares Using SDO /HMI Vector Magnetic Data Products and the Random Forest Algorithm

    Liu, Chang; Deng, Na; Wang, Haimin [Space Weather Research Laboratory, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States); Wang, Jason T. L., E-mail: chang.liu@njit.edu, E-mail: na.deng@njit.edu, E-mail: haimin.wang@njit.edu, E-mail: jason.t.wang@njit.edu [Department of Computer Science, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States)

    2017-07-10

    Adverse space-weather effects can often be traced to solar flares, the prediction of which has drawn significant research interests. The Helioseismic and Magnetic Imager (HMI) produces full-disk vector magnetograms with continuous high cadence, while flare prediction efforts utilizing this unprecedented data source are still limited. Here we report results of flare prediction using physical parameters provided by the Space-weather HMI Active Region Patches (SHARP) and related data products. We survey X-ray flares that occurred from 2010 May to 2016 December and categorize their source regions into four classes (B, C, M, and X) according to the maximum GOES magnitude of flares they generated. We then retrieve SHARP-related parameters for each selected region at the beginning of its flare date to build a database. Finally, we train a machine-learning algorithm, called random forest (RF), to predict the occurrence of a certain class of flares in a given active region within 24 hr, evaluate the classifier performance using the 10-fold cross-validation scheme, and characterize the results using standard performance metrics. Compared to previous works, our experiments indicate that using the HMI parameters and RF is a valid method for flare forecasting with fairly reasonable prediction performance. To our knowledge, this is the first time that RF has been used to make multiclass predictions of solar flares. We also find that the total unsigned quantities of vertical current, current helicity, and flux near the polarity inversion line are among the most important parameters for classifying flaring regions into different classes.

  8. Mechanisms for multiple activity modes of VTA dopamine neurons

    Andrew eOster

    2015-07-01

    Full Text Available Midbrain ventral segmental area (VTA dopaminergic neurons send numerous projections to cortical and sub-cortical areas, and diffusely release dopamine (DA to their targets. DA neurons display a range of activity modes that vary in frequency and degree of burst firing. Importantly, DA neuronal bursting is associated with a significantly greater degree of DA release than an equivalent tonic activity pattern. Here, we introduce a single compartmental, conductance-based computational model for DA cell activity that captures the behavior of DA neuronal dynamics and examine the multiple factors that underlie DA firing modes: the strength of the SK conductance, the amount of drive, and GABA inhibition. Our results suggest that neurons with low SK conductance fire in a fast firing mode, are correlated with burst firing, and require higher levels of applied current before undergoing depolarization block. We go on to consider the role of GABAergic inhibition on an ensemble of dynamical classes of DA neurons and find that strong GABA inhibition suppresses burst firing. Our studies suggest differences in the distribution of the SK conductance and GABA inhibition levels may indicate subclasses of DA neurons within the VTA. We further identify, that by considering alternate potassium dynamics, the dynamics display burst patterns that terminate via depolarization block, akin to those observed in vivo in VTA DA neurons and in substantia nigra pars compacta DA cell preparations under apamin application. In addition, we consider the generation of transient burst firing events that are NMDA-initiated or elicited by a sudden decrease of GABA inhibition, that is, disinhibition.

  9. Increased microglial catalase activity in multiple sclerosis grey matter.

    Gray, Elizabeth; Kemp, Kevin; Hares, Kelly; Redondo, Julianna; Rice, Claire; Scolding, Neil; Wilkins, Alastair

    2014-04-22

    Chronic demyelination, on-going inflammation, axonal loss and grey matter neuronal injury are likely pathological processes that contribute to disease progression in multiple sclerosis (MS). Although the precise contribution of each process and their aetiological substrates is not fully known, recent evidence has implicated oxidative damage as a major cause of tissue injury in MS. The degree of tissue injury caused by oxidative molecules, such as reactive oxygen species (ROS), is balanced by endogenous anti-oxidant enzymes which detoxify ROS. Understanding endogenous mechanisms which protect the brain against oxidative injury in MS is important, since enhancing anti-oxidant responses is a major therapeutic strategy for preventing irreversible tissue injury in the disease. Our aims were to determine expression and activity levels of the hydrogen peroxide-reducing enzyme catalase in MS grey matter (GM). In MS GM, a catalase enzyme activity was elevated compared to control GM. We measured catalase protein expression by immune dot-blotting and catalase mRNA by a real-time polymerase chain reaction (RT-PCR). Protein analysis studies showed a strong positive correlation between catalase and microglial marker IBA-1 in MS GM. In addition, calibration of catalase mRNA level with reference to the microglial-specific transcript AIF-1 revealed an increase in this transcript in MS. This was reflected by the extent of HLA-DR immunolabeling in MS GM which was significantly elevated compared to control GM. Collectively, these observations provide evidence that microglial catalase activity is elevated in MS grey matter and may be an important endogenous anti-oxidant defence mechanism in MS. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Coupled flare attractors – a discrete prototype for economic modelling

    Georg C. Hartmann

    1999-01-01

    Full Text Available A chaotic environment can give rise to “flares” if an autocatalytic variable responds in a multiplicative, threshold-type fashion to the environmental forcing. An “economic unit” similarly depends in its growth behavior on the unpredictable (chaotic? buying habits of its customers, say. It turns out that coupled flare attractors are surprisingly robust in the sense that the resulting “economy” is largely independent of the extent of diffusive coupling used. Some simulations are presented.

  11. The Effects of Flare Definitions on the Statistics of Derived Flare Distrubtions

    Ryan, Daniel; Dominique, Marie; Seaton, Daniel B.; Stegen, Koen; White, Arthur

    2016-05-01

    The statistical examination of solar flares is crucial to revealing their global characteristics and behaviour. However, statistical flare studies are often performed using standard but basic flare detection algorithms relying on arbitrary thresholds which may affect the derived flare distributions. We explore the effect of the arbitrary thresholds used in the GOES event list and LYRA Flare Finder algorithms. We find that there is a small but significant relationship between the power law exponent of the GOES flare peak flux frequency distribution and the algorithms’ flare start thresholds. We also find that the power law exponents of these distributions are not stable but appear to steepen with increasing peak flux. This implies that the observed flare size distribution may not be a power law at all. We show that depending on the true value of the exponent of the flare size distribution, this deviation from a power law may be due to flares missed by the flare detection algorithms. However, it is not possible determine the true exponent from GOES/XRS observations. Additionally we find that the PROBA2/LYRA flare size distributions are clearly non-power law. We show that this is consistent with an insufficient degradation correction which causes LYRA absolute irradiance values to be unreliable. This means that they should not be used for flare statistics or energetics unless degradation is adequately accounted for. However they can be used to study time variations over shorter timescales and for space weather monitoring.

  12. 3D Filament Network Segmentation with Multiple Active Contours

    Xu, Ting; Vavylonis, Dimitrios; Huang, Xiaolei

    2014-03-01

    Fluorescence microscopy is frequently used to study two and three dimensional network structures formed by cytoskeletal polymer fibers such as actin filaments and microtubules. While these cytoskeletal structures are often dilute enough to allow imaging of individual filaments or bundles of them, quantitative analysis of these images is challenging. To facilitate quantitative, reproducible and objective analysis of the image data, we developed a semi-automated method to extract actin networks and retrieve their topology in 3D. Our method uses multiple Stretching Open Active Contours (SOACs) that are automatically initialized at image intensity ridges and then evolve along the centerlines of filaments in the network. SOACs can merge, stop at junctions, and reconfigure with others to allow smooth crossing at junctions of filaments. The proposed approach is generally applicable to images of curvilinear networks with low SNR. We demonstrate its potential by extracting the centerlines of synthetic meshwork images, actin networks in 2D TIRF Microscopy images, and 3D actin cable meshworks of live fission yeast cells imaged by spinning disk confocal microscopy.

  13. Foretelling Flares and Solar Energetic Particle Events: the FORSPEF tool

    Anastasiadis, Anastasios; Papaioannou, Athanasios; Sandberg, Ingmar; Georgoulis, Manolis K.; Tziotziou, Kostas; Jiggens, Piers

    2017-04-01

    A novel integrated prediction system, for both solar flares (SFs) and solar energetic particle (SEP) events is being presented. The Forecasting Solar Particle Events and Flares (FORSPEF) provides forecasting of solar eruptive events, such as SFs with a projection to coronal mass ejections (CMEs) (occurrence and velocity) and the likelihood of occurrence of a SEP event. In addition, FORSPEF, also provides nowcasting of SEP events based on actual SF and CME near real-time data, as well as the complete SEP profile (peak flux, fluence, rise time, duration) per parent solar event. The prediction of SFs relies on a morphological method: the effective connected magnetic field strength (Beff); it is based on an assessment of potentially flaring active-region (AR) magnetic configurations and it utilizes sophisticated analysis of a large number of AR magnetograms. For the prediction of SEP events new methods have been developed for both the likelihood of SEP occurrence and the expected SEP characteristics. In particular, using the location of the flare (longitude) and the flare size (maximum soft X-ray intensity), a reductive statistical method has been implemented. Moreover, employing CME parameters (velocity and width), proper functions per width (i.e. halo, partial halo, non-halo) and integral energy (E>30, 60, 100 MeV) have been identified. In our technique warnings are issued for all > C1.0 soft X-ray flares. The prediction time in the forecasting scheme extends to 24 hours with a refresh rate of 3 hours while the respective prediction time for the nowcasting scheme depends on the availability of the near real-time data and falls between 15-20 minutes for solar flares and 6 hours for CMEs. We present the modules of the FORSPEF system, their interconnection and the operational set up. The dual approach in the development of FORPSEF (i.e. forecasting and nowcasting scheme) permits the refinement of predictions upon the availability of new data that characterize changes on

  14. Incidence and factors related to flare-ups in a graduate endodontic programme.

    Iqbal, M; Kurtz, E; Kohli, M

    2009-02-01

    To investigate the incidence and factors related to endodontic flare-ups in nonsurgical root canal treatment (NSRCT) cases completed by graduate endodontic residents at University of Pennsylvania, USA. Residents at University of Pennsylvania enter all clinical patient records into an electronic database called PennEndo database. Analysis of records of 6580 patients treated from September 2000 to July 2005 revealed a total of 26 patients with flare-ups (0.39%). Patients were categorized to have undergone flare-up when they attended for an unscheduled visit and active treatment, and when they suffered from severe pain and or swelling after initiation or continuation of NSRCT. SAS software was used to develop a logistic regression model with flare-up as a dependent variable. Independent variables included in the model were: history of previous pain, one vs. two visit NSRCT, periapical diagnosis, tooth type, rotary versus hand instrumentation, and lateral versus vertical compaction of gutta-percha. The odds for developing a flare-up in teeth with a periapical radiolucency were 9.64 times greater than teeth without a periapical radiolucency (P = 0.0090). There was no statistically significant difference in flare-ups between one and two visits NSRCT. The odds of developing a flare-up increased 40 fold when NSRCT was completed in three or more visits. However, this result may have been confounded by addition of an unscheduled visit in patients suffering from flare-ups. Other independent variables did not have any statistically significant correlations. A low percentage of patients experienced flare-ups during NSRCT procedures. The presence of a periapical lesion was the single most important predictor of flare-ups during NSRCT.

  15. CD4 T cell activation and disease activity at onset of multiple sclerosis

    Jensen, J; Langkilde, Annika Reynberg; Fenst, C

    2004-01-01

    We studied CD4 T cell activation in patients with clinically isolated syndromes (CIS) suggesting an initial attack of multiple sclerosis. The percentage of blood CD26+ CD4 T cells was increased in these patients, and correlated with magnetic resonance imaging disease activity and clinical disease...... severity. In contrast, the percentage of CD25+ CD4 T cells in cerebrospinal fluid correlated negatively with the cerebrospinal fluid concentration of myelin basic protein and the presence of IgG oligoclonal bands. These results suggest that distinct systemic and intrathecal T cell activation states...

  16. Multiple Active Volcanoes in the Northeast Lau Basin

    Baker, E. T.; Resing, J. A.; Lupton, J. E.; Walker, S. L.; Embley, R. W.; Rubin, K. H.; Buck, N.; de Ronde, C. E.; Arculus, R. J.

    2010-12-01

    The northeast Lau Basin occupies a complex geological area between the Tafua arc front, the E-W trending Tonga Trench, and the Northeast Lau Spreading Center. These boundaries create multiple zones of extension and thus provide abundant opportunities for magma to invade the crust. The 25-km-long chain of “Mata” volcanoes lies near the center of this area, separated from both the arc front and the spreading ridge. In 2008 we discovered hydrothermal venting on the largest and most southerly of these volcanoes, W and E Mata. In 2010 we visited the 7 smaller volcanoes that form a 15-km-long arcuate sweep to the north from W and E Mata (the “North Matas”). We also revisited W and E Mata. Over each volcano we conducted CTD tows to map plumes and collect water samples. Based on the CTD results, camera tows searched for seafloor sources on three volcanoes. The N Mata volcanoes, extending from Mata Taha (1) in the south to Mata Fitu (7) in the north, lie within a prominent gap in the shallow bathymetry along the southern border of the Tonga trench. Northward from E Mata the Mata volcanoes degrade from large symmetrical cones to smaller and blocky volcanic edifices. Summit depths range from 1165 m (W Mata) to 2670 m (Mata Nima (5)). The most active volcano in the chain is the erupting W Mata, with an intense plume that extended 250 m above the summit. Hydrothermal temperature anomalies (Δθ, corrected for hydrographic masking effects) reached ˜1.7°C, with light-scattering values as high as 2-5 ΔNTU. The 2010 surveys now show that 6 of the 7 N Mata volcanoes are also hydrothermally active. Along the N Matas, Δθ and ΔNTU signals ranged from robust to weak, but distinct oxidation-reduction potential (aka Eh) anomalies confirmed active venting in each case. The most concentrated plumes were found near Mata Ua (2) and Mata Fitu (7), with Δθ and ΔNTU maxima of 0.1-0.17°C and 0.3, respectively. Despite the variability in plume strength, however, ΔNTU/Δθ ratios

  17. Solar Indices - Solar Flares

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  18. Search for relation between flares and photometric variability outside of flares in EV Lac

    Rojzman, G.Sh.

    1984-01-01

    The observations of the flare star EV Lac in July-September 1981 have confirmed the existence of photometric variability outside the flares during the night. It was found that, as a rule, a slow increase of brightness in U and B bands during 1-2 hours preceded the flares. It is suggested that the variability outside the flares is the result of the variability of chpomospheric emission lines and continuum that are emitted by the chromospheric preflare formations

  19. Physical activity and exercise priorities in community dwelling people with multiple sclerosis: a Delphi study.

    Stennett, Andrea; De Souza, Lorraine; Norris, Meriel

    2018-07-01

    Exercise and physical activity have been found to be beneficial in managing disabilities caused by multiple sclerosis. Despite the known benefits, many people with multiple sclerosis are inactive. This study aimed to identify the prioritised exercise and physical activity practices of people with multiple sclerosis living in the community and the reasons why they are engaged in these activities. A four Round Delphi questionnaire scoped and determined consensus of priorities for the top 10 exercise and physical activities and the reasons why people with multiple sclerosis (n = 101) are engaged in these activities. Data were analysed using content analysis, descriptive statistics, and non-parametric tests. The top 10 exercise and physical activity practices and the top 10 reasons why people with multiple sclerosis (n = 70) engaged in these activities were identified and prioritised. Consensus was achieved for the exercise and physical activities (W = 0.744, p multiple sclerosis engaged in exercise and physical activity were diverse. These self-selected activities and reasons highlighted that people with multiple sclerosis might conceptualise exercise and physical activity in ways that may not be fully appreciated or understood by health professionals. Considerations of the views of people with multiple sclerosis may be essential if the goal of increasing physical activity in this population is to be achieved. Implications for Rehabilitation Health professionals should work collaboratively with people with multiple sclerosis to understand how they prioritise activities, the underlying reasons for their prioritisations and embed these into rehabilitation programmes. Health professionals should utilise activities prioritised by people with multiple sclerosis in the community as a way to support, promote, and sustain exercise and physical activity in this population. Rehabilitation interventions should include both the activities people with multiple

  20. Dwarf Star Erupts in Giant Flare

    2005-01-01

    This movie taken by NASA'S Galaxy Evolution Explorer shows one of the largest flares, or star eruptions, ever recorded at ultraviolet wavelengths. The star, called GJ 3685A, just happened to be in the Galaxy Evolution Explorer's field of view while the telescope was busy observing galaxies. As the movie demonstrates, the seemingly serene star suddenly exploded once, then even more intensely a second time, pouring out in total about one million times more energy than a typical flare from our Sun. The second blast of light constituted an increase in brightness by a factor of at least 10,000. Flares are huge explosions of energy stemming from a single location on a star's surface. They are caused by the brief destruction of a star's magnetic fields. Many types of stars experience them, though old, small, rapidly rotating 'red dwarfs' like GJ 3685A tend to flare more frequently and dramatically. These stars, called flare stars, can experience powerful eruptions as often as every few hours. Younger stars, in general, also erupt more often. One of the reasons astronomers study flare stars is to gain a better picture and history of flare events taking place on the Sun. A preliminary analysis of the GJ 3685A flare shows that the mechanisms underlying stellar eruptions may be more complex than previously believed. Evidence for the two most popular flare theories was found. Though this movie has been sped up (the actual flare lasted about 20 minutes), time-resolved data exist for each one-hundredth of a second. These observations were taken at 2 p.m. Pacific time, April 24, 2004. In the still image, the time sequence starts in the upper left panel, continues in the upper right, then moves to the lower left and ends in the lower right. The circular and linear features that appear below and to the right of GJ 3685A during the flare event are detector artifacts caused by the extreme brightness of the flare.

  1. Solar flares through electric current interaction

    De Jager, C.

    1988-01-01

    The fundamental hypothesis by Alfven and Carlqvist (1967) that solar flares are related to electrical currents in the solar chromosphere and low corona is investigated in the light of modern observations. The authors confirm the important role of currents in solar flares. There must be tens of such current loops (flux threads) in any flare, and this explains the hierarchy of bursts in flares. The authors summarize quantitative data on energies, numbers of particles involved and characteristic times. A special case is the high-energy flare: this one may originate in the same way as less energetic ones, but it occurs in regions with higher magnetic field strength. Because of the high particle energies involved their emission seats live only very briefly; hence the area of emission coincides virtually with the seat of the instability. These flares are therefore the best examples for studying the primary instability leading to the flare. Finally, the authors compare the merits of the original Alfven-Carlqvist idea (that flares originate by current interruption) with the one that they are due to interaction (reconnection) between two or more fluxthreads. The authors conclude that a final decision cannot yet by made, although the observed extremely short time constants of flare bursts seem to demand a reconnection-type instability rather than interruption of a circuit

  2. Bright x-ray flares in gamma-ray burst afterglows.

    Burrows, D N; Romano, P; Falcone, A; Kobayashi, S; Zhang, B; Moretti, A; O'brien, P T; Goad, M R; Campana, S; Page, K L; Angelini, L; Barthelmy, S; Beardmore, A P; Capalbi, M; Chincarini, G; Cummings, J; Cusumano, G; Fox, D; Giommi, P; Hill, J E; Kennea, J A; Krimm, H; Mangano, V; Marshall, F; Mészáros, P; Morris, D C; Nousek, J A; Osborne, J P; Pagani, C; Perri, M; Tagliaferri, G; Wells, A A; Woosley, S; Gehrels, N

    2005-09-16

    Gamma-ray burst (GRB) afterglows have provided important clues to the nature of these massive explosive events, providing direct information on the nearby environment and indirect information on the central engine that powers the burst. We report the discovery of two bright x-ray flares in GRB afterglows, including a giant flare comparable in total energy to the burst itself, each peaking minutes after the burst. These strong, rapid x-ray flares imply that the central engines of the bursts have long periods of activity, with strong internal shocks continuing for hundreds of seconds after the gamma-ray emission has ended.

  3. Very fast optical flaring from a possible new Galactic magnetar.

    Stefanescu, A; Kanbach, G; Słowikowska, A; Greiner, J; McBreen, S; Sala, G

    2008-09-25

    Highly luminous rapid flares are characteristic of processes around compact objects like white dwarfs, neutron stars and black holes. In the high-energy regime of X-rays and gamma-rays, outbursts with variabilities on timescales of seconds or less are routinely observed, for example in gamma-ray bursts or soft gamma-ray repeaters. At optical wavelengths, flaring activity on such timescales has not been observed, other than from the prompt phase of one exceptional gamma-ray burst. This is mostly due to the fact that outbursts with strong, fast flaring are usually discovered in the high-energy regime; most optical follow-up observations of such transients use instruments with integration times exceeding tens of seconds, which are therefore unable to resolve fast variability. Here we show the observation of extremely bright and rapid optical flaring in the Galactic transient SWIFT J195509.6+261406. Our optical light curves are phenomenologically similar to high-energy light curves of soft gamma-ray repeaters and anomalous X-ray pulsars, which are thought to be neutron stars with extremely high magnetic fields (magnetars). This suggests that similar processes are in operation, but with strong emission in the optical, unlike in the case of other known magnetars.

  4. Expanding CME-flare relations to other stellar systems

    Moschou, Sofia P.; Drake, Jeremy J.; Cohen, Ofer

    2017-05-01

    Stellar activity is one of the main parameters in exoplanet habitability studies. While the effects of UV to X-ray emission from extreme flares on exoplanets are beginning to be investigated, the impact of coronal mass ejections is currently highly speculative because CMEs and their properties cannot yet be directly observed on other stars. An extreme superflare was observed in X-rays on the Algol binary system on August 30 1997, emitting a total of energy 1.4x 10^{37} erg and making it a great candidate for studying the upper energy limits of stellar superflares in solar-type (GK) stars. A simultaneous increase and subsequent decline in absorption during the flare was also observed and interpretted as being caused by a CME. Here we investigate the dynamic properties of a CME that could explain such time-dependent absorption and appeal to trends revealed from solar flare and CME statistics as a guide. Using the ice-cream cone model that is extensively used in solar physics to describe the three-dimensional CME structure, in combination with the temporal profile of the hydrogen column density evolution, we are able to characterize the CME and estimate its kinetic energy and mass. We examine the mass, kinetic and flare X-ray fluence in the context of solar relations to examine the extent to which such relations can be extrapolated to much more extreme stellar events.

  5. Internal and External Reconnection Series Homologous Solar Flares

    Sterling, Alphonse C.; Moore, Ronald L.

    2001-01-01

    Using data from the extreme ultraviolet imaging telescope (EIT) on SOHO and the soft X-ray telescope (SXT) on Yohkoh, we examine a series of morphologically homologous solar flares occurring in National Oceanic and Atmospheric Administration (NOAA) active region 8210 over May 1-2, 1998. An emerging flux region (EFR) impacted against a sunspot to the west and next to a coronal hole to the east is the source of the repeated flaring. An SXT sigmoid parallels the EFR's neutral line at the site of the initial flaring in soft X rays. In EIT each flaring episode begins with the formation of a crinkle pattern external to the EFR. These EIT crinkles move out from, and then in toward, the EFR with velocities approx. 20 km/ s. A shrinking and expansion of the width of the coronal hole coincides with the crinkle activity, and generation and evolution of a postflare loop system begins near the time of crinkle formation. Using a schematic based on magnetograms of the region, we suggest that these observations are consistent with the standard reconnection-based model for solar eruptions but are modified by the presence of the additional magnetic fields of the sunspot and coronal hole. In the schematic, internal reconnection begins inside of the EFR-associated fields, unleashing a flare, postflare loops, and a coronal mass ejection (CME). External reconnection, first occurring between the escaping CME and the coronal hole field and second occurring between fields formed as a result of the first external reconnection, results in the EIT crinkles and changes in the coronal hole boundary. By the end of the second external reconnection, the initial setup is reinstated; thus the sequence can repeat, resulting in morphologically homologous eruptions. Our inferred magnetic topology is similar to that suggested in the "breakout model" of eruptions although we cannot determine if our eruptions are released primarily by the breakout mechanism (external reconnection) or, alternatively

  6. Multiple-source multiple-harmonic active vibration control of variable section cylindrical structures: A numerical study

    Liu, Jinxin; Chen, Xuefeng; Gao, Jiawei; Zhang, Xingwu

    2016-12-01

    Air vehicles, space vehicles and underwater vehicles, the cabins of which can be viewed as variable section cylindrical structures, have multiple rotational vibration sources (e.g., engines, propellers, compressors and motors), making the spectrum of noise multiple-harmonic. The suppression of such noise has been a focus of interests in the field of active vibration control (AVC). In this paper, a multiple-source multiple-harmonic (MSMH) active vibration suppression algorithm with feed-forward structure is proposed based on reference amplitude rectification and conjugate gradient method (CGM). An AVC simulation scheme called finite element model in-loop simulation (FEMILS) is also proposed for rapid algorithm verification. Numerical studies of AVC are conducted on a variable section cylindrical structure based on the proposed MSMH algorithm and FEMILS scheme. It can be seen from the numerical studies that: (1) the proposed MSMH algorithm can individually suppress each component of the multiple-harmonic noise with an unified and improved convergence rate; (2) the FEMILS scheme is convenient and straightforward for multiple-source simulations with an acceptable loop time. Moreover, the simulations have similar procedure to real-life control and can be easily extended to physical model platform.

  7. Impact of psoriasis flare and remission on quality of life and work productivity: a real-world study in the USA.

    Korman, N J; Zhao, Y; Roberts, J; Pike, J; Sullivan, E; Tsang, Y; Karagiannis, T

    2016-07-15

    Although psoriasis patients often report a negative impact on health-related quality of life (HRQoL) and work productivity, less is known about how disease burden varies between periods of flare and remission. The aim of this study was tocompare HRQoL and work productivity by disease activity level. Data were extracted from Adelphi 2011/2013 Disease Specific Programmes, two real world surveys of US dermatologists and psoriasis patients. HRQoL was measured using the EuroQOL 5-Dimension Health Questionnaire (EQ-5D) and Dermatology Life Quality Index (DLQI). Work productivity was measured using the Work Productivity Activity index (WPAI). Three levels of disease activity were constructed based on physician reports: remission, active not flaring, active, and flaring. Multivariable regression analyses explored the relationship between disease activity, HRQoL and work productivity, controlling for differences in demographics and comorbidities. Out of 681 psoriasis patients 24% were in remission, 62% had active disease without flaring, and 15% experienced active disease and were currently flaring. Greater disease activity was associated with worse HRQoL. EQ-5D scores decreased with more active disease (remission vs. active not flaring vs. active and flaring: 0.93 vs. 0.90 vs. 0.82; p<0.05), while DLQI scores increased (remission vs. active not flaring vs. active and flaring: 2.0 vs. 5.00 vs. 8.7; p<0.05). WPAI scores increased with disease activity indicating increased productivity loss (remission vs. active not flaring vs. active and flaring: 5.9 vs. 14.8 vs. 26.9; p<0.05). The same trends were confirmed by multivariable regression analyses.

  8. Flare pit reclamation in British Columbia

    Mitchell, J.D.

    1997-01-01

    The legislative acts and policies administered by the Pollution Prevention program of the B.C. Ministry of Environment, Lands and Parks, (MELP) were reviewed. MELP is responsible for protecting land, water, air and living resources. Past oil and gas activities have left behind high levels of hazardous materials spills on the land which can pose a risk to human health. Flare pits are also a potential source of soil and groundwater contamination, therefore proper management and remediation of these sites is critical to ensuring that adverse impacts do not occur due to contamination of the sites. MELP has created a Contaminated Sites Regulation (CSR) which presents a consistent approach to ensuring protection of human health, the environment and property. This paper explores key provisions of the CSR, the prescribed contaminated sites management process and compares the B.C. legislation with that of neighbouring Alberta. 5 refs., 1 tab., 4 figs

  9. Prior Flaring as a Complement to Free Magnetic Energy for Forecasting Solar Eruptions

    Falconer, David A.; Moore, Ronald L.; Barghouty, Abdulnasser F.; Khazanov, Igor

    2012-01-01

    From a large database of (1) 40,000 SOHO/MDI line-of-sight magnetograms covering the passage of 1,300 sunspot active regions across the 30 deg radius central disk of the Sun, (2) a proxy of each active region's free magnetic energy measured from each of the active region's central-disk-passage magnetograms, and (3) each active region's full-disk-passage history of production of major flares and fast coronal mass ejections (CMEs), we find new statistical evidence that (1) there are aspects of an active region's magnetic field other than the free energy that are strong determinants of the active region's productivity of major flares and fast CMEs in the coming few days, (2) an active region's recent productivity of major flares, in addition to reflecting the amount of free energy in the active region, also reflects these other determinants of coming productivity of major eruptions, and (3) consequently, the knowledge of whether an active region has recently had a major flare, used in combination with the active region's free-energy proxy measured from a magnetogram, can greatly alter the forecast chance that the active region will have a major eruption in the next few days after the time of the magnetogram. The active-region magnetic conditions that, in addition to the free energy, are reflected by recent major flaring are presumably the complexity and evolution of the field.

  10. PRIOR FLARING AS A COMPLEMENT TO FREE MAGNETIC ENERGY FOR FORECASTING SOLAR ERUPTIONS

    Falconer, David A.; Moore, Ronald L.; Barghouty, Abdulnasser F.; Khazanov, Igor

    2012-01-01

    From a large database of (1) 40,000 SOHO/MDI line-of-sight magnetograms covering the passage of 1300 sunspot active regions across the 30° radius central disk of the Sun, (2) a proxy of each active region's free magnetic energy measured from each of the active region's central-disk-passage magnetograms, and (3) each active region's full-disk-passage history of production of major flares and fast coronal mass ejections (CMEs), we find new statistical evidence that (1) there are aspects of an active region's magnetic field other than the free energy that are strong determinants of the active region's productivity of major flares and fast CMEs in the coming few days; (2) an active region's recent productivity of major flares, in addition to reflecting the amount of free energy in the active region, also reflects these other determinants of coming productivity of major eruptions; and (3) consequently, the knowledge of whether an active region has recently had a major flare, used in combination with the active region's free-energy proxy measured from a magnetogram, can greatly alter the forecast chance that the active region will have a major eruption in the next few days after the time of the magnetogram. The active-region magnetic conditions that, in addition to the free energy, are reflected by recent major flaring are presumably the complexity and evolution of the field.

  11. FAST CONTRACTION OF CORONAL LOOPS AT THE FLARE PEAK

    Liu Rui; Wang Haimin

    2010-01-01

    On 2005 September 8, a coronal loop overlying the active region NOAA 10808 was observed in TRACE 171 A to contract at ∼100 km s -1 at the peak of an X5.4-2B flare at 21:05 UT. Prior to the fast contraction, the loop underwent a much slower contraction at ∼6 km s -1 for about 8 minutes, initiating during the flare preheating phase. The sudden switch to fast contraction is presumably corresponding to the onset of the impulsive phase. The contraction resulted in the oscillation of a group of loops located below, with the period of about 10 minutes. Meanwhile, the contracting loop exhibited a similar oscillatory pattern superimposed on the dominant downward motion. We suggest that the fast contraction reflects a suddenly reduced magnetic pressure underneath due either to (1) the eruption of magnetic structures located at lower altitudes or to (2) the rapid conversion of magnetic free energy in the flare core region. Electrons accelerated in the shrinking trap formed by the contracting loop can theoretically contribute to a late-phase hard X-ray burst, which is associated with Type IV radio emission. To complement the X5.4 flare which was probably confined, a similar event observed in SOHO/EIT 195 A on 2004 July 20 in an eruptive, M8.6 flare is briefly described, in which the contraction was followed by the expansion of the same loop leading up to a halo coronal mass ejection. These observations further substantiate the conjecture of coronal implosion and suggest coronal implosion as a new exciter mechanism for coronal loop oscillations.

  12. THE THERMAL PROPERTIES OF SOLAR FLARES OVER THREE SOLAR CYCLES USING GOES X-RAY OBSERVATIONS

    Ryan, Daniel F.; Gallagher, Peter T.; Milligan, Ryan O.; Dennis, Brian R.; Kim Tolbert, A.; Schwartz, Richard A.; Alex Young, C.

    2012-01-01

    Solar flare X-ray emission results from rapidly increasing temperatures and emission measures in flaring active region loops. To date, observations from the X-Ray Sensor (XRS) on board the Geostationary Operational Environmental Satellite (GOES) have been used to derive these properties, but have been limited by a number of factors, including the lack of a consistent background subtraction method capable of being automatically applied to large numbers of flares. In this paper, we describe an automated Temperature and Emission measure-Based Background Subtraction method (TEBBS), that builds on the methods of Bornmann. Our algorithm ensures that the derived temperature is always greater than the instrumental limit and the pre-flare background temperature, and that the temperature and emission measure are increasing during the flare rise phase. Additionally, TEBBS utilizes the improved estimates of GOES temperatures and emission measures from White et al. TEBBS was successfully applied to over 50,000 solar flares occurring over nearly three solar cycles (1980-2007), and used to create an extensive catalog of the solar flare thermal properties. We confirm that the peak emission measure and total radiative losses scale with background subtracted GOES X-ray flux as power laws, while the peak temperature scales logarithmically. As expected, the peak emission measure shows an increasing trend with peak temperature, although the total radiative losses do not. While these results are comparable to previous studies, we find that flares of a given GOES class have lower peak temperatures and higher peak emission measures than previously reported. The TEBBS database of flare thermal plasma properties is publicly available at http://www.SolarMonitor.org/TEBBS/.

  13. Diagnostics of solar flare reconnection

    M. Karlický

    2004-01-01

    Full Text Available We present new diagnostics of the solar flare reconnection, mainly based on the plasma radio emission. We propose that the high-frequency (600-2000 MHz slowly drifting pulsating structures map the flare magnetic field reconnection. These structures correspond to the radio emission from plasmoids which are formed in the extended current sheet due to tearing and coalescence processes. An increase of the frequency drift of the drifting structures is interpreted as an increase of the reconnection rate. Using this model, time scales of slowly drifting pulsating structure observed during the 12 April 2001 flare by the Trieste radiopolarimeter with high time resolution (1 ms are interpreted as a radio manifestation of electron beams accelerated in the multi-scale reconnection process. For short periods Fourier spectra of the observed structure have a power-law form with power-law indices in the 1.3-1.6 range. For comparison the 2-D MHD numerical modeling of the multi-scale reconnection is made and it is shown that Fourier spectrum of the reconnection dissipation power has also a power-law form, but with power-law index 2. Furthermore, we compute a time evolution of plasma parameters (density, magnetic field etc in the 2-D MHD model of the reconnection. Then assuming a plasma radio emission from locations, where the 'double-resonance' instability generates the upper-hybrid waves due to unstable distribution function of suprathermal electrons, we model radio spectra. Effects of the MHD turbulence are included. The resulting spectra are compared with those observed. It is found, that depending on model parameters the lace bursts and the decimetric spikes can be reproduced. Thus, it is shown that the model can be used for diagnostics of the flare reconnection process. We also point out possible radio signatures of reconnection outflow termination shocks. They are detected as type II-like herringbone structures in the 200-700 MHz frequency range. Finally

  14. Adhesion molecules levels in blood correlate with MRI activity and clinical activity in multiple sclerosis

    Millers, A.; Enina, G.; Platkajis, A.; Metra, M.; Kukaine, R.

    2002-01-01

    Research into pathogenesis of multiple sclerosis (MS) has prompted efforts to identify immunological markers associated with disease activity. Adhesion molecules ICAM-1 and VCAM-1 are associated with inflammatory mediated blood-brain barrier (BBB) dysfunction. In this study investigates the correlation between blood level of circulating ICAM-1 and VCAM-1 and magnetic resonance imaging (MRI) activity in different clinical phases of patients with MS. We show that RRMS and SPMS patients in clinically active phase with Gd-enhancing lesions in CNS had higher blood levels of cICAM-1 and cVCAM-1 compared these parameters levers of RRMS patients in remission stage. These results suggest that cICAM-1 and cVCAM-1 is a sensitive indicator of disease activity associated with BBB inflammatory dysfunction. Elevated blood level of cICAM-1 more strongly correlated with clinical activity and BBB damage, than cVCAM-1 and that could be used as biological marker of disease activity. Circulating VCAM-1 as an early indicator of BBB disturbance, may also serve as marker of beneficial activity in relapses phase of MS course. (authors)

  15. Activation of endogenous neural stem cells for multiple sclerosis therapy

    Michailidou, I.; de Vries, H.E.; Hol, E.M.; van Strien, M.E.

    2015-01-01

    Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system, leading to severe neurological deficits. Current MS treatment regimens, consist of immunomodulatory agents aiming to reduce the rate of relapses. However, these agents are usually insufficient to treat chronic

  16. A Bayesian method for detecting stellar flares

    Pitkin, M.; Williams, D.; Fletcher, L.; Grant, S. D. T.

    2014-12-01

    We present a Bayesian-odds-ratio-based algorithm for detecting stellar flares in light-curve data. We assume flares are described by a model in which there is a rapid rise with a half-Gaussian profile, followed by an exponential decay. Our signal model also contains a polynomial background model required to fit underlying light-curve variations in the data, which could otherwise partially mimic a flare. We characterize the false alarm probability and efficiency of this method under the assumption that any unmodelled noise in the data is Gaussian, and compare it with a simpler thresholding method based on that used in Walkowicz et al. We find our method has a significant increase in detection efficiency for low signal-to-noise ratio (S/N) flares. For a conservative false alarm probability our method can detect 95 per cent of flares with S/N less than 20, as compared to S/N of 25 for the simpler method. We also test how well the assumption of Gaussian noise holds by applying the method to a selection of `quiet' Kepler stars. As an example we have applied our method to a selection of stars in Kepler Quarter 1 data. The method finds 687 flaring stars with a total of 1873 flares after vetos have been applied. For these flares we have made preliminary characterizations of their durations and and S/N.

  17. X-ray Emission from Solar Flares

    2016-01-27

    Jan 27, 2016 ... Solar flares; X-ray detectors; X-ray line emission and continuum; break energy; microflares. Abstract. Solar X-ray Spectrometer (SOXS), the first space-borne solar astronomy experiment of India was designed to improve our current understanding of X-ray emission from the Sun in general and solar flares in ...

  18. Offshore production flares: a PETROBRAS review

    Pagot, Paulo R.; Burmann, Clovis P.; Araujo, Paulo Bento de; Motomura, Tsukasa [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The purpose of the present work is to briefly present the offshore flare system technological evolution and the main design criteria for flare and its supporting structure. In order to perform the aimed task, this work was divided into two parts: the first part presents the technological evolution of the offshore production flares and the second one discusses the flare system designing criteria. The evolution of the technology associated to the offshore production flares is organized by the authors just dividing the history in four chronological phases. Each phase is defined by the predominant use of the, by the time, most up-to-date technological alternative and it will be described with the help of sketches, drawings, photographs, data and information about the platforms where such technologies were applied. The second part of the present work discusses the dimensional criteria, interesting aspects and flaws of the offshore flare systems in two different fields, which are: definition of the flare system capacity; and flow and thermal design of the flare system. (author)

  19. 40 CFR 63.987 - Flare requirements.

    2010-07-01

    ... specified in paragraphs (b)(3)(i) through (iv) of this section. (i) Method 22 of appendix A of part 60 shall...) cross sectional area of the flare tip. (iv) Flare flame or pilot monitors, as applicable, shall be..., ultra-violet beam sensor, or infrared sensor) capable of continuously detecting that at least one pilot...

  20. Fast electrons in small solar flares

    Lin, R.P.

    1975-01-01

    Because approximately 5-100 keV electrons are frequently accelerated and emitted by the Sun in small flares, it is possible to define a detailed characteristic physical picture of these events. The review summarizes both the direct spacecraft observations of non-relativistic solar electrons, and observations of the X-ray and radio emission generated by these particles at the Sun and in the interplanetary medium. These observations bear on the basic astrophysical process of particle acceleration in tenuous plasmas. It is found that in many small solar flares the approximately 5-100 keV electrons accelerated during flash phase constitute the bulk of the total flare energy. Thus the basic flare mechanism in these flares essentially converts the available flare energy into fast electrons. These electrons may produce the other flare electromagnetic emissions through their interactions with the solar atmosphere. In large proton flares these electrons may provide the energy to eject material from the Sun and to create a shock wave which could then accelerate nuclei and electrons to much higher energies. (Auth.)

  1. New flare stars in the Pleiade. 3

    Parsamyan, Eh.S.

    1976-01-01

    The flare stars in the Pleiads were investigated. The observations were carried out from the second part of 1972 to the beginning of 1973. Data on 9 new and 9 repeat flares are given. The new data are compared with those obtained previously

  2. Solar flare irradiation records in Antarctic meteorites

    Goswami, J.N.

    1981-01-01

    Observations of solar flare heavy nuclei tracks in eight Antartic meteorite samples are reported. Two of these were interior specimens from an L-3 chondrite which contained track-rich grains (olivine) indicating their exposure to solar flare irradiation before compaction of the meteorite. Preliminary noble gas data also indicate the presence of solar-type gases. (U.K.)

  3. ASASSN-16ae: A POWERFUL WHITE-LIGHT FLARE ON AN EARLY-L DWARF

    Schmidt, Sarah J.; Shappee, Benjamin J.; Seibert, Mark; Gagné, Jonathan; Stanek, K. Z.; Holoien, Thomas W.-S.; Kochanek, C. S.; Prieto, José L.; Chomiuk, Laura; Strader, Jay; Dong, Subo

    2016-01-01

    We report the discovery and classification of SDSS J053341.43+001434.1 (SDSS0533), an early-L dwarf first discovered during a powerful Δ V 3.7 × 10"3"4 erg), placing it among the strongest detected M dwarf flares. The presence of this powerful flare on an old L0 dwarf may indicate that stellar-type magnetic activity persists down to the end of the main sequence and on older ML transition dwarfs.

  4. Deep Learning Based Solar Flare Forecasting Model. I. Results for Line-of-sight Magnetograms

    Huang, Xin; Wang, Huaning; Xu, Long; Liu, Jinfu; Li, Rong; Dai, Xinghua

    2018-03-01

    Solar flares originate from the release of the energy stored in the magnetic field of solar active regions, the triggering mechanism for these flares, however, remains unknown. For this reason, the conventional solar flare forecast is essentially based on the statistic relationship between solar flares and measures extracted from observational data. In the current work, the deep learning method is applied to set up the solar flare forecasting model, in which forecasting patterns can be learned from line-of-sight magnetograms of solar active regions. In order to obtain a large amount of observational data to train the forecasting model and test its performance, a data set is created from line-of-sight magnetogarms of active regions observed by SOHO/MDI and SDO/HMI from 1996 April to 2015 October and corresponding soft X-ray solar flares observed by GOES. The testing results of the forecasting model indicate that (1) the forecasting patterns can be automatically reached with the MDI data and they can also be applied to the HMI data; furthermore, these forecasting patterns are robust to the noise in the observational data; (2) the performance of the deep learning forecasting model is not sensitive to the given forecasting periods (6, 12, 24, or 48 hr); (3) the performance of the proposed forecasting model is comparable to that of the state-of-the-art flare forecasting models, even if the duration of the total magnetograms continuously spans 19.5 years. Case analyses demonstrate that the deep learning based solar flare forecasting model pays attention to areas with the magnetic polarity-inversion line or the strong magnetic field in magnetograms of active regions.

  5. Exploring the Connection between Parsec-scale Jet Activity and Broadband Outbursts in 3C 279

    Rani, B.; Jorstad, S. G.; Marscher, A. P.; Agudo, I.; Sokolovsky, K. V.; Larionov, V. M.; Smith, P.; Mosunova, D. A.; Borman, G. A.; Grishina, T. S.; Kopatskaya, E. N.; Mokrushina, A. A.; Morozova, D. A.; Savchenko, S. S.; Troitskaya, Yu. V.; Troitsky, I. S.; Thum, C.; Molina, S. N.; Casadio, C.

    2018-05-01

    We use a combination of high-resolution very long baseline interferometry (VLBI) radio and multiwavelength flux density and polarization observations to constrain the physics of the dissipation mechanism powering the broadband flares in 3C 279 during an episode of extreme flaring activity in 2013–2014. Six bright flares superimposed on a long-term outburst are detected at γ-ray energies. Four of the flares have optical and radio counterparts. The two modes of flaring activity (faster flares sitting on top of a long-term outburst) present at radio, optical, and γ-ray frequencies are missing in X-rays. X-ray counterparts are only observed for two flares. The first three flares are accompanied by ejection of a new VLBI component (NC2), suggesting the 43 GHz VLBI core as the site of energy dissipation. Another new component, NC3, is ejected after the last three flares, which suggests that the emission is produced upstream from the core (closer to the black hole). The study therefore indicates multiple sites of energy dissipation in the source. An anticorrelation is detected between the optical percentage polarization (PP) and optical/γ-ray flux variations, while the PP has a positive correlation with optical/γ-ray spectral indices. Given that the mean polarization is inversely proportional to the number of cells in the emission region, the PP versus optical/γ-ray anticorrelation could be due to more active cells during the outburst than at other times. In addition to the turbulent component, our analysis suggests the presence of a combined turbulent and ordered magnetic field, with the ordered component transverse to the jet axis.

  6. Simulating the Mg II NUV Spectra & C II Resonance Lines During Solar Flares

    Kerr, Graham Stewart; Allred, Joel C.; Leenaarts, Jorrit; Butler, Elizabeth; Kowalski, Adam

    2017-08-01

    The solar chromosphere is the origin of the bulk of the enhanced radiative output during solar flares, and so comprehensive understanding of this region is important if we wish to understand energy transport in solar flares. It is only relatively recently, however, with the launch of IRIS that we have routine spectroscopic flarea observations of the chromsphere and transition region. Since several of the spectral lines observed by IRIS are optically thick, it is necessary to use forward modelling to extract the useful information that these lines carry about the flaring chromosphere and transition region. We present the results of modelling the formation properties Mg II resonance lines & subordinate lines, and the C II resonance lines during solar flares. We focus on understanding their relation to the physical strucutre of the flaring atmosphere, exploiting formation height differences to determine if we can extract information about gradients in the atmosphere. We show the effect of degrading the profiles to the resolution of the IRIS, and that the usual observational techniques used to identify the line centroid do a poor job in the early stages of the flare (partly due to multiple optically thick line components). Finally, we will tentatively comment on the effects that 3D radiation transfer may have on these lines.

  7. Quasi-periodic Oscillations in Flares and Coronal Mass Ejections Associated with Magnetic Reconnection

    Takahashi, Takuya; Shibata, Kazunari [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Qiu, Jiong, E-mail: takahasi@kusastro.kyoto-u.ac.jp [Department of Physics, Montana State University, Bozeman, MT 59717-3840 (United States)

    2017-10-20

    We propose a mechanism for quasi-periodic oscillations of both coronal mass ejections (CMEs) and flare loops as related to magnetic reconnection in eruptive solar flares. We perform two-dimensional numerical MHD simulations of magnetic flux rope eruption, with three different values of the global Lundquist number. In the low Lundquist number run, no oscillatory behavior is found. In the moderate Lundquist number run, on the other hand, quasi-periodic oscillations are excited both at the bottom of the flux rope and at the flare loop top. In the high Lundquist number run, quasi-periodic oscillations are also excited; in the meanwhile, the dynamics become turbulent owing to the formation of multiple plasmoids in the reconnection current sheet. In high and moderate Lundquist number runs, thin reconnection jets collide with the flux rope bottom or flare loop top and dig them deeply. Steep oblique shocks are formed as termination shocks where reconnection jets are bent (rather than decelerated) in the horizontal direction, resulting in supersonic backflows. The structure becomes unstable, and quasi-periodic oscillations of supersonic backflows appear at locally confined high-beta regions at both the flux rope bottom and flare loop top. We compare the observational characteristics of quasi-periodic oscillations in erupting flux ropes, post-CME current sheets, flare ribbons, and light curves with corresponding dynamical structures found in our simulation.

  8. Magnetic-Island Contraction and Particle Acceleration in Simulated Eruptive Solar Flares

    Guidoni, S. E.; Devore, C. R.; Karpen, J. T.; Lynch, B. J.

    2016-01-01

    The mechanism that accelerates particles to the energies required to produce the observed high-energy impulsive emission in solar flares is not well understood. Drake et al. proposed a mechanism for accelerating electrons in contracting magnetic islands formed by kinetic reconnection in multi-layered current sheets (CSs). We apply these ideas to sunward-moving flux ropes (2.5D magnetic islands) formed during fast reconnection in a simulated eruptive flare. A simple analytic model is used to calculate the energy gain of particles orbiting the field lines of the contracting magnetic islands in our ultrahigh-resolution 2.5D numerical simulation. We find that the estimated energy gains in a single island range up to a factor of five. This is higher than that found by Drake et al. for islands in the terrestrial magnetosphere and at the heliopause, due to strong plasma compression that occurs at the flare CS. In order to increase their energy by two orders of magnitude and plausibly account for the observed high-energy flare emission, the electrons must visit multiple contracting islands. This mechanism should produce sporadic emission because island formation is intermittent. Moreover, a large number of particles could be accelerated in each magneto hydro dynamic-scale island, which may explain the inferred rates of energetic-electron production in flares. We conclude that island contraction in the flare CS is a promising candidate for electron acceleration in solar eruptions.

  9. A Parameter Study for Modeling Mg ii h and k Emission during Solar Flares

    Rubio da Costa, Fatima [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Kleint, Lucia, E-mail: frubio@stanford.edu [University of Applied Sciences and Arts Northwestern Switzerland, 5210, Windisch (Switzerland)

    2017-06-20

    Solar flares show highly unusual spectra in which the thermodynamic conditions of the solar atmosphere are encoded. Current models are unable to fully reproduce the spectroscopic flare observations, especially the single-peaked spectral profiles of the Mg ii h and k lines. We aim to understand the formation of the chromospheric and optically thick Mg ii h and k lines in flares through radiative transfer calculations. We take a flare atmosphere obtained from a simulation with the radiative hydrodynamic code RADYN as input for a radiative transfer modeling with the RH code. By iteratively changing this model atmosphere and varying thermodynamic parameters such as temperature, electron density, and velocity, we study their effects on the emergent intensity spectra. We reproduce the typical single-peaked Mg ii h and k flare spectral shape and approximate the intensity ratios to the subordinate Mg ii lines by increasing either densities, temperatures, or velocities at the line core formation height range. Additionally, by combining unresolved upflows and downflows up to ∼250 km s{sup −1} within one resolution element, we reproduce the widely broadened line wings. While we cannot unambiguously determine which mechanism dominates in flares, future modeling efforts should investigate unresolved components, additional heat dissipation, larger velocities, and higher densities and combine the analysis of multiple spectral lines.

  10. Energetic Particle Estimates for Stellar Flares

    Youngblood, Allison; Chamberlin, Phil; Woods, Tom

    2018-01-01

    In the heliosphere, energetic particles are accelerated away from the Sun during solar flares and/or coronal mass ejections where they frequently impact the Earth and other solar system bodies. Solar (or stellar) energetic particles (SEPs) not only affect technological assets, but also influence mass loss and chemistry in planetary atmospheres (e.g., depletion of ozone). SEPs are increasingly recognized as an important factor in assessing exoplanet habitability, but we do not yet have constraints on SEP emission from any stars other than the Sun. Until indirect measurements are available, we must assume solar-like particle production and apply correlations between solar flares and SEPs detected near Earth to stellar flares. We present improved scaling relations between solar far-UV flare flux and >10 MeV proton flux near Earth. We apply these solar scaling relations to far-UV flares from exoplanet host stars and discuss the implications for modeling chemistry and mass loss in exoplanet atmospheres.

  11. Models of spots and flares

    Mullan, D.J.

    1983-01-01

    Laboratory experiments in recent years have shown that there are many more ways to drive a plasma out of equilibrium than to preserve equilibrium. In that sense, it is perhaps easier to understand why flares should occur in a stellar atmosphere than why a long-lived feature such as a dark spot should persist. The author summarizes work on the equilibrium structure of cool spots in the sun and stars. Since spots involve complex interactions between convective flows and magnetic fields, he needs to refer to observations for help in identifying the dominant processes which should enter into the modelling. His summary therefore begins by discussing certain relevant properties of spots in the solar atmosphere. The next sections deal with the magnetic fields in spots, the stability of spots, spot cooling and missing flux. The author concludes that spots should be viewed not simply as cool areas, but rather as engines which do the work of converting the energy of convective flows into flare-compatible form. (Auth.)

  12. June-July 1974 proton-flare region. III

    Bumba, V.

    1982-01-01

    In this third part of a series of papers describing the regularities in the magnetic field as well as solar activity development in a large portion of the solar atmosphere in which the processes related to the June-July 1974 proton-flare region formation take place, we study some characteristics of the solar wind which emanates from this portion of the solar atmosphere. It is shown that during the time when fast disintegration and disappearance of the large-scale characteristic magnetic field patterns occur and a sudden cease of sunspot, flare and coronal activity is observed, daily geomagnetic character figures C9 reach their maximum. This solar wind enhancement is taken as one of the last observable manifestations of the whole complex process. (author)

  13. Multiple nucleophilic elbows leading to multiple active sites in a single module esterase from Sorangium cellulosum

    Udatha, D.B.R.K. Gupta; Madsen, Karina Marie; Panagiotou, Gianni

    2015-01-01

    The catalytic residues in carbohydrate esterase enzyme families constitute a highly conserved triad: serine, histidine and aspartic acid. This catalytic triad is generally located in a very sharp turn of the protein backbone structure, called the nucleophilic elbow and identified by the consensus...... sequence GXSXG. An esterase from Sorangium cellulosum Soce56 that contains five nucleophilic elbows was cloned and expressed in Escherichia coli and the function of each nucleophilic elbowed site was characterized. In order to elucidate the function of each nucleophilic elbow, site directed mutagenesis....... To our knowledge, this is the first report presenting the role of multiple nucleophilic elbows in the catalytic promiscuity of an esterase. Further structural analysis at protein unit level indicates the new evolutionary trajectories in emerging promiscuous esterases....

  14. Observational constraints on the inter-binary stellar flare hypothesis for the gamma-ray bursts

    Rao, A. R.; Vahia, M. N.

    1994-01-01

    The Gamma Ray Observatory/Burst and Transient Source Experiment (GRO/BATSE) results on the Gamma Ray Bursts (GRBs) have given an internally consistent set of observations of about 260 GRBs which have been released for analysis by the BATSE team. Using this database we investigate our earlier suggestion (Vahia and Rao, 1988) that GRBs are inter-binary stellar flares from a group of objects classified as Magnetically Active Stellar Systems (MASS) which includes flare stars, RS CVn binaries and cataclysmic variables. We show that there exists an observationally consistent parameter space for the number density, scale height and flare luminosity of MASS which explains the complete log(N) - log(P) distribution of GRBs as also the observed isotropic distribution. We further use this model to predict anisotropy in the GRB distribution at intermediate luminosities. We make definite predictions under the stellar flare hypothesis that can be tested in the near future.

  15. Serial MRI studies using gadolinium DTPA in active multiple sclerosis

    Miller, D.H.; Johnson, G.; Barnes, D.; Rudge, P.; McDonald, W.I.

    1988-01-01

    It has been suggested that blood brain barrier (BBB) impairment is a necessary early event in the pathogenesis of the multiple sclerosis (MS) lesions. To evaluate such an hypothesis in vivo would require: (1) serial imaging studies using a modality with high sensitivity for detecting plaques; (2) a contrast enhancing agent which demonstrates BBB impairment. A serial magnetic resonance imaging (MRI) study was undertaken of a group of MS patients using the contrast agent gadolinium-DTPA. As it has been suggested that T 1 and T 2 relaxation times are longer in acute than chronic MS lesions, these were also measured. 3 refs.; 1 figure

  16. Identifying core domains to assess flare in rheumatoid arthritis

    Bartlett, Susan J; Hewlett, Sarah; Bingham, Clifton O

    2012-01-01

    For rheumatoid arthritis (RA), there is no consensus on how to define and assess flare. Variability in flare definitions impairs understanding of findings across studies and limits ability to pool results. The OMERACT RA Flare Group sought to identify domains to define RA flares from patient...

  17. The NWRA Classification Infrastructure: description and extension to the Discriminant Analysis Flare Forecasting System (DAFFS)

    Leka, K. D.; Barnes, Graham; Wagner, Eric

    2018-04-01

    A classification infrastructure built upon Discriminant Analysis (DA) has been developed at NorthWest Research Associates for examining the statistical differences between samples of two known populations. Originating to examine the physical differences between flare-quiet and flare-imminent solar active regions, we describe herein some details of the infrastructure including: parametrization of large datasets, schemes for handling "null" and "bad" data in multi-parameter analysis, application of non-parametric multi-dimensional DA, an extension through Bayes' theorem to probabilistic classification, and methods invoked for evaluating classifier success. The classifier infrastructure is applicable to a wide range of scientific questions in solar physics. We demonstrate its application to the question of distinguishing flare-imminent from flare-quiet solar active regions, updating results from the original publications that were based on different data and much smaller sample sizes. Finally, as a demonstration of "Research to Operations" efforts in the space-weather forecasting context, we present the Discriminant Analysis Flare Forecasting System (DAFFS), a near-real-time operationally-running solar flare forecasting tool that was developed from the research-directed infrastructure.

  18. PROBING THE FLARE ATMOSPHERES OF M DWARFS USING INFRARED EMISSION LINES

    Schmidt, Sarah J.; Kowalski, Adam F.; Hawley, Suzanne L.; Hilton, Eric J.; Wisniewski, John P.; Tofflemire, Benjamin M., E-mail: sjschmidt@astro.washington.edu [Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council of Canada (Canada)

    2012-01-20

    We present the results of a campaign to monitor active M dwarfs using infrared spectroscopy, supplemented with optical photometry and spectroscopy. We detected 16 flares during nearly 50 hr of observations on EV Lac, AD Leo, YZ CMi, and VB 8. The three most energetic flares also showed infrared emission, including the first reported detections of P{beta}, P{gamma}, He I {lambda}10830, and Br{gamma} during an M dwarf flare. The strongest flare ({Delta}u = 4.02 on EV Lac) showed emission from H{gamma}, H{delta}, He I {lambda}4471, and Ca II K in the UV/blue and P{beta}, P{gamma}, P{delta}, Br{gamma}, and He I {lambda}10830 in the infrared. The weaker flares ({Delta}u = 1.68 on EV Lac and {Delta}U = 1.38 on YZ CMi) were only observed with photometry and infrared spectroscopy; both showed emission from P{beta}, P{gamma}, and He I {lambda}10830. The strongest infrared emission line, P{beta}, occurred in the active mid-M dwarfs with a duty cycle of {approx}3%-4%. To examine the most energetic flare, we used the static NLTE radiative transfer code RH to produce model spectra based on a suite of one-dimensional model atmospheres. Using a hotter chromosphere than previous one-dimensional atmospheric models, we obtain line ratios that match most of the observed emission lines.

  19. Solar flare leaves sun quaking

    1998-05-01

    Dr. Alexander G. Kosovichev, a senior research scientist from Stanford University, and Dr. Valentina V. Zharkova from Glasgow (United Kingdom) University found the tell-tale seismic signature in data on the Sun's surface collected by the Michelson Doppler Imager onboard the Solar and Heliospheric Observatory (SOHO) spacecraft immediately following a moderate-sized flare on July 9, 1996. "Although the flare was a moderate one, it still released an immense amount of energy," said Dr. Craig Deforest, a researcher with the SOHO project. "The energy released is equal to completely covering the Earth's continents with a yard of dynamite and detonating it all at once." SOHO is a joint project of the European Space Agency and NASA. The finding is reported in the May 28 issue of the journal Nature, and is the subject of a press conference at the spring meeting of the American Geophysical Union in Boston, Mass., May 27. The solar quake that the science team recorded looks much like ripples spreading from a rock dropped into a pool of water. But over the course of an hour, the solar waves traveled for a distance equal to 10 Earth diameters before fading into the fiery background of the Sun's photosphere. Unlike water ripples that travel outward at a constant velocity, the solar waves accelerated from an initial speed of 22,000 miles per hour to a maximum of 250,000 miles per hour before disappearing. "People have looked for evidence of seismic waves from flares before, but they didn't have a theory so they didn't know where to look," says Kosovichev. Several years ago Kosovichev and Zharkova developed a theory that can explain how a flare, which explodes in space above the Sun's surface, can generate a major seismic wave in the Sun's interior. According to the currently accepted model of solar flares, the primary explosion creates high-energy electrons (electrically charged subatomic particles). These are funneled down into a magnetic flux tube, an invisible tube of magnetic

  20. SOLAR FLARE PREDICTION USING SDO/HMI VECTOR MAGNETIC FIELD DATA WITH A MACHINE-LEARNING ALGORITHM

    Bobra, M. G.; Couvidat, S.

    2015-01-01

    We attempt to forecast M- and X-class solar flares using a machine-learning algorithm, called support vector machine (SVM), and four years of data from the Solar Dynamics Observatory's Helioseismic and Magnetic Imager, the first instrument to continuously map the full-disk photospheric vector magnetic field from space. Most flare forecasting efforts described in the literature use either line-of-sight magnetograms or a relatively small number of ground-based vector magnetograms. This is the first time a large data set of vector magnetograms has been used to forecast solar flares. We build a catalog of flaring and non-flaring active regions sampled from a database of 2071 active regions, comprised of 1.5 million active region patches of vector magnetic field data, and characterize each active region by 25 parameters. We then train and test the machine-learning algorithm and we estimate its performances using forecast verification metrics with an emphasis on the true skill statistic (TSS). We obtain relatively high TSS scores and overall predictive abilities. We surmise that this is partly due to fine-tuning the SVM for this purpose and also to an advantageous set of features that can only be calculated from vector magnetic field data. We also apply a feature selection algorithm to determine which of our 25 features are useful for discriminating between flaring and non-flaring active regions and conclude that only a handful are needed for good predictive abilities

  1. Angiogenic activity of sesamin through the activation of multiple signal pathways

    Chung, Byung-Hee; Lee, Jung Joon; Kim, Jong-Dai; Jeoung, Dooil; Lee, Hansoo; Choe, Jongseon; Ha, Kwon-Soo; Kwon, Young-Geun; Kim, Young-Myeong

    2010-01-01

    The natural product sesamin has been known to act as a potent antioxidant and prevent endothelial dysfunction. We here found that sesamin increased in vitro angiogenic processes, such as endothelial cell proliferation, migration, and tube formation, as well as neovascularization in an animal model. This compound elicited the activation of multiple angiogenic signal modulators, such as ERK, Akt, endothelial nitric oxide synthase (eNOS), NO production, FAK, and p38 MAPK, but not Src. The MEK inhibitor PD98059 and the PI3K inhibitor Wortmannin specifically inhibited sesamin-induced activation of the ERK and Akt/eNOS pathways. These inhibitors reduced angiogenic events, with high specificity for MEK/ERK-dependent cell proliferation and migration and PI3K/Akt-mediated tube formation. Moreover, inhibition of p38 MAPK effectively inhibited sesamin-induced cell migration. The angiogenic activity of sesamin was not associated with VEGF expression. Furthermore, this compound did not induce vascular permeability and upregulated ICAM-1 and VCAM-1 expression, which are hallmarks of vascular inflammation. These results suggest that sesamin stimulates angiogenesis in vitro and in vivo through the activation of MEK/ERK-, PI3K/Akt/eNOS-, p125 FAK -, and p38 MAPK-dependent pathways, without increasing vascular inflammation, and may be used for treating ischemic diseases and tissue regeneration.

  2. Large roads reduce bat activity across multiple species.

    Kitzes, Justin; Merenlender, Adina

    2014-01-01

    Although the negative impacts of roads on many terrestrial vertebrate and bird populations are well documented, there have been few studies of the road ecology of bats. To examine the effects of large roads on bat populations, we used acoustic recorders to survey bat activity along ten 300 m transects bordering three large highways in northern California, applying a newly developed statistical classifier to identify recorded calls to the species level. Nightly counts of bat passes were analyzed with generalized linear mixed models to determine the relationship between bat activity and distance from a road. Total bat activity recorded at points adjacent to roads was found to be approximately one-half the level observed at 300 m. Statistically significant road effects were also found for the Brazilian free-tailed bat (Tadarida brasiliensis), big brown bat (Eptesicus fuscus), hoary bat (Lasiurus cinereus), and silver-haired bat (Lasionycteris noctivagans). The road effect was found to be temperature dependent, with hot days both increasing total activity at night and reducing the difference between activity levels near and far from roads. These results suggest that the environmental impacts of road construction may include degradation of bat habitat and that mitigation activities for this habitat loss may be necessary to protect bat populations.

  3. A satellite-based analysis of the Val d'Agri (South of Italy) Oil Center gas flaring emissions

    Faruolo, M.; Coviello, I.; Filizzola, C.; Lacava, T.; Pergola, N.; Tramutoli, V.

    2014-06-01

    In this paper the Robust Satellite Techniques (RST), a multi-temporal scheme of satellite data analysis, was implemented to analyze the flaring activity of the largest Italian gas and oil pre-treatment plant (i.e. the Ente Nazionale Idrocarburi - ENI - Val d'Agri Oil Center - COVA). For this site, located in an anthropized area characterized by a~large environmental complexity, flaring emissions are mainly related to emergency conditions (i.e. waste flaring), being the industrial process regulated by strict regional laws. With reference to the peculiar characteristics of COVA flaring, the main aim of this work was to assess the performances of RST in terms of sensitivity and reliability in providing independent estimations of gas flaring volumes in such conditions. In detail, RST was implemented on thirteen years of Moderate Resolution Imaging Spectroradiometer (MODIS) medium and thermal infrared data in order to identify the highly radiant records associated to the COVA flare emergency discharges. Then, exploiting data provided by ENI about gas flaring volumes in the period 2003-2009, a MODIS-based regression model was developed and tested. Achieved results indicate that such a model is able to estimate, with a good level of accuracy (R2 of 0.83), emitted gas flaring volumes at COVA.

  4. A satellite-based analysis of the Val d'Agri Oil Center (southern Italy) gas flaring emissions

    Faruolo, M.; Coviello, I.; Filizzola, C.; Lacava, T.; Pergola, N.; Tramutoli, V.

    2014-10-01

    In this paper, the robust satellite techniques (RST), a multi-temporal scheme of satellite data analysis, was implemented to analyze the flaring activity of the Val d'Agri Oil Center (COVA), the largest Italian gas and oil pre-treatment plant, owned by Ente Nazionale Idrocarburi (ENI). For this site, located in an anthropized area characterized by a large environmental complexity, flaring emissions are mainly related to emergency conditions (i.e., waste flaring), as industrial processes are regulated by strict regional laws. While regarding the peculiar characteristics of COVA flaring, the main aim of this work was to assess the performances of RST in terms of sensitivity and reliability in providing independent estimations of gas flaring volumes in such conditions. In detail, RST was implemented for 13 years of Moderate Resolution Imaging Spectroradiometer (MODIS) medium and thermal infrared data in order to identify the highly radiant records associated with the COVA flare emergency discharges. Then, using data provided by ENI about gas flaring volumes in the period 2003-2009, a MODIS-based regression model was developed and tested. The results achieved indicate that the such a model is able to estimate, with a good level of accuracy (R2 of 0.83), emitted gas flaring volumes at COVA.

  5. Radio imaging of solar flares using the very large array - New insights into flare process

    Kundu, M. R.; Schmahl, E. J.; Vlahos, L.; Velusamy, T.

    1982-01-01

    An interpretation of VLA observations of microwave bursts is presented in an attempt to distinguish between certain models of flares. The VLA observations provide information about the pre-flare magnetic field topology and the existence of mildly relativistic electrons accelerated during flares. Examples are shown of changes in magnetic field topology in the hour before flares. In one case, new bipolar loops appear to emerge, which is an essential component of the model developed by Heyvaerts et al. (1977). In another case, a quadrupole structure, suggestive of two juxtaposed bipolar loops, appears to trigger the flare. Because of the observed diversity of magnetic field topologies in microwave bursts, it is believed that the magnetic energy must be dissipated in more than one way. The VLA observations are clearly providing means for sorting out the diverse flare models.

  6. Graphical analysis of processes with multiple activation energies

    Lachter, J.; Bragg, R.H.; Close, E.

    1986-01-01

    The activation energies characterizing a kinetic process are derived from the slopes of the Arrhenius diagrams obtained by plotting rate constants versus reciprocal temperature. Those rate constants correspond to the shifts along the time axis needed to superpose the successive isotherms. A general method based on Chebyshev interpolation is proposed for the optimization of the superposition of the experimental data points. This method is applied to determine the activation energies of the graphitization kinetics of the interlayer spacings of pitch coke and pyrocarbon samples

  7. Physical activity staging distribution: establishing a heuristic using multiple studies.

    Nigg, C; Hellsten, L; Norman, G; Braun, L; Breger, R; Burbank, P; Coday, M; Elliot, D; Garber, C; Greaney, M; Keteyian, S; Lees, F; Matthews, C; Moe, E; Resnick, B; Riebe, D; Rossi, J; Toobert, D; Wang, T; Welk, G; Williams, G

    2005-04-01

    The purpose of this study was to identify the population prevalence across the stages of change (SoC) for regular physical activity and to establish the prevalence of people at risk. With support from the National Institutes of Health, the American Heart Association, and the Robert Wood Johnson Foundation, nine Behavior Change Consortium studies with a common physical activity SoC measure agreed to collaborate and share data. The distribution pattern identified in these predominantly reactively recruited studies was Precontemplation (PC) = 5% (+/- 10), Contemplation (C) = 10% (+/- 10), Preparation (P) = 40% (+/- 10), Action = 10% (+/- 10), and Maintenance = 35% (+/- 10). With reactively recruited studies, it can be anticipated that there will be a higher percentage of the sample that is ready to change and a greater percentage of currently active people compared to random representative samples. The at-risk stage distribution (i.e., those not at criteria or PC, C, and P) was approximately 10% PC, 20% C, and 70% P in specific samples and approximately 20% PC, 10% C, and 70% P in the clinical samples. Knowing SoC heuristics can inform public health practitioners and policymakers about the population's motivation for physical activity, help track changes over time, and assist in the allocation of resources.

  8. IMPLOSION OF CORONAL LOOPS DURING THE IMPULSIVE PHASE OF A SOLAR FLARE

    Simões, P. J. A.; Fletcher, L.; Hudson, H. S.; Russell, A. J. B., E-mail: paulo.simoes@glasgow.ac.uk, E-mail: lyndsay.fletcher@glasgow.ac.uk, E-mail: arussell@maths.dundee.ac.uk, E-mail: hhudson@ssl.berkeley.edu [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2013-11-10

    We study the relationship between implosive motions in a solar flare, and the energy redistribution in the form of oscillatory structures and particle acceleration. The flare SOL2012-03-09T03:53 (M6.4) shows clear evidence for an irreversible (stepwise) coronal implosion. Extreme-ultraviolet (EUV) images show at least four groups of coronal loops at different heights overlying the flaring core undergoing fast contraction during the impulsive phase of the flare. These contractions start around a minute after the flare onset, and the rate of contraction is closely associated with the intensity of the hard X-ray and microwave emissions. They also seem to have a close relationship with the dimming associated with the formation of the coronal mass ejection and a global EUV wave. Several studies now have detected contracting motions in the corona during solar flares that can be interpreted as the implosion necessary to release energy. Our results confirm this, and tighten the association with the flare impulsive phase. We add to the phenomenology by noting the presence of oscillatory variations revealed by Geostationary Operational Environmental Satellite soft X-rays (SXR) and spatially integrated EUV emission at 94 and 335 Å. We identify pulsations of ≈60 s in SXR and EUV data, which we interpret as persistent, semi-regular compressions of the flaring core region which modulate the plasma temperature and emission measure. The loop oscillations, observed over a large region, also allow us to provide rough estimates of the energy temporarily stored in the eigenmodes of the active-region structure as it approaches its new equilibrium.

  9. Flare Energy Release: Internal Conflict, Contradiction with High Resolution Observations, Possible Solutions

    Pustilnik, L.

    2017-06-01

    All accepted paradigm of solar and stellar flares energy release based on 2 whales: 1. Source of energy is free energy of non-potential force free magnetic field in atmosphere above active region; 2. Process of ultrafast dissipation of magnetic fields is Reconnection in Thin Turbulent Current Sheet (RTTCS). Progress in observational techniques in last years provided ultra-high spatial resolution and in physics of turbulent plasma showed that real situation is much more complicated and standard approach is in contradiction both with observations and with problem of RTTCS stability. We present critical analysis of classic models of pre-flare energy accumulation and its dissipation during flare energy release from pioneer works Giovanelli (1939, 1947) up to topological reconnection. We show that all accepted description of global force-free fields as source of future flare cannot be agreed with discovered in last years fine and ultra-fine current-magnetic structure included numerouse arcs-threads with diameters up to 100 km with constant sequence from photosphere to corona. This magnetic skeleton of thin current magnetic threads with strong interaction between them is main source of reserved magnetic energy insolar atmosphere. Its dynamics will be controlled by percolation of magnetic stresses through network of current-magnetic threads with transition to flare state caused by critical value of global current. We show that thin turbulent current sheet is absolutely unstable configuration both caused by splitting to numerous linear currents by dissipative modes like to tearing, and as sequence of suppress of plasma turbulence caused by anomalous heating of turbulent plasma. In result of these factors primary RTTCS will be disrupted in numerous turbulent and normal plasma domains like to resistors network. Current propagation through this network will have percolation character with all accompanied properties of percolated systems: self-organization with formation power

  10. Fermi -LAT Observations of High-energy Behind-the-limb Solar Flares

    Ackermann, M.; Buehler, R. [Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany); Allafort, A.; Bottacini, E.; Cameron, R. A.; Charles, E. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Baldini, L. [Università di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa I-56127 Pisa (Italy); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bellazzini, R. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bissaldi, E.; Caragiulo, M.; Costanza, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari (Italy); Bonino, R. [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino (Italy); Bregeon, J. [Laboratoire Univers et Particules de Montpellier, Université Montpellier, CNRS/IN2P3, F-34095 Montpellier (France); Bruel, P. [Laboratoire Leprince-Ringuet, École polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); Caraveo, P. A. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via E. Bassini 15, I-20133 Milano (Italy); Cavazzuti, E.; Ciprini, S. [Agenzia Spaziale Italiana (ASI) Science Data Center, I-00133 Roma (Italy); Cecchi, C., E-mail: nicola.omodei@stanford.edu, E-mail: vahep@stanford.edu, E-mail: melissa.pesce.rollins@pi.infn.it [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); and others

    2017-02-01

    We report on the Fermi -LAT detection of high-energy emission from the behind-the-limb (BTL) solar flares that occurred on 2013 October 11, and 2014 January 6 and September 1. The Fermi -LAT observations are associated with flares from active regions originating behind both the eastern and western limbs, as determined by STEREO . All three flares are associated with very fast coronal mass ejections (CMEs) and strong solar energetic particle events. We present updated localizations of the >100 MeV photon emission, hard X-ray (HXR) and EUV images, and broadband spectra from 10 keV to 10 GeV, as well as microwave spectra. We also provide a comparison of the BTL flares detected by Fermi -LAT with three on-disk flares and present a study of some of the significant quantities of these flares as an attempt to better understand the acceleration mechanisms at work during these occulted flares. We interpret the HXR emission to be due to electron bremsstrahlung from a coronal thin-target loop top with the accelerated electron spectra steepening at semirelativistic energies. The >100 MeV gamma-rays are best described by a pion-decay model resulting from the interaction of protons (and other ions) in a thick-target photospheric source. The protons are believed to have been accelerated (to energies >10 GeV) in the CME environment and precipitate down to the photosphere from the downstream side of the CME shock and landed on the front side of the Sun, away from the original flare site and the HXR emission.

  11. The Effect of Magnetic Topology on the Escape of Flare Particles

    Antiochos, S. K.; Masson, S.; DeVore, C. R.

    2012-01-01

    Magnetic reconnection in the solar atmosphere is believed to be the driver of most solar explosive phenomena. Therefore, the topology of the coronal magnetic field is central to understanding the solar drivers of space weather. Of particular importance to space weather are the impulsive Solar Energetic particles that are associated with some CME/eruptive flare events. Observationally, the magnetic configuration of active regions where solar eruptions originate appears to agree with the standard eruptive flare model. According to this model, particles accelerated at the flare reconnection site should remain trapped in the corona and the ejected plasmoid. However, flare-accelerated particles frequently reach the Earth long before the CME does. We present a model that may account for the injection of energetic particles onto open magnetic flux tubes connecting to the Earth. Our model is based on the well-known 2.5D breakout topology, which has a coronal null point (null line) and a four-flux system. A key new addition, however, is that we include an isothermal solar wind with open-flux regions. Depending on the location of the open flux with respect to the null point, we find that the flare reconnection can consist of two distinct phases. At first, the flare reconnection involves only closed field, but if the eruption occurs close to the open field, we find a second phase involving interchange reconnection between open and closed. We argue that this second reconnection episode is responsible for the injection of flare-accelerated particles into the interplanetary medium. We will report on our recent work toward understanding how flare particles escape to the heliosphere. This work uses high-resolution 2.5D MHD numerical simulations performed with the Adaptively Refined MHD Solver (ARMS).

  12. Multiplicative multifractal modeling and discrimination of human neuronal activity

    Zheng Yi; Gao Jianbo; Sanchez, Justin C.; Principe, Jose C.; Okun, Michael S.

    2005-01-01

    Understanding neuronal firing patterns is one of the most important problems in theoretical neuroscience. It is also very important for clinical neurosurgery. In this Letter, we introduce a computational procedure to examine whether neuronal firing recordings could be characterized by cascade multiplicative multifractals. By analyzing raw recording data as well as generated spike train data from 3 patients collected in two brain areas, the globus pallidus externa (GPe) and the globus pallidus interna (GPi), we show that the neural firings are consistent with a multifractal process over certain time scale range (t 1 ,t 2 ), where t 1 is argued to be not smaller than the mean inter-spike-interval of neuronal firings, while t 2 may be related to the time that neuronal signals propagate in the major neural branching structures pertinent to GPi and GPe. The generalized dimension spectrum D q effectively differentiates the two brain areas, both intra- and inter-patients. For distinguishing between GPe and GPi, it is further shown that the cascade model is more effective than the methods recently examined by Schiff et al. as well as the Fano factor analysis. Therefore, the methodology may be useful in developing computer aided tools to help clinicians perform precision neurosurgery in the operating room

  13. Implications of NRL/ATM solar flare observations on flare theories

    Cheng, C.C.; Spicer, D.S.

    1975-01-01

    During the Skylab mission, many solar flares were observed with the NRL XUV spectroheliogram in the wavelength region from 150 to 650 A. Because of its high spatial resolution (approximately 2ins.) the three-dimensional structures of the flare emission regions characterized by temperatures from 10 4 K to 20 x 10 6 K can be resolved. Thus the spatial relationship between the relatively cool plasma and the hot plasma components of a flare, and the associated magnetic field structure can be inferred. The implications for various flare models are discussed. (Auth.)

  14. K2 Ultracool Dwarfs Survey. II. The White Light Flare Rate of Young Brown Dwarfs

    Gizis, John E.; Paudel, Rishi R.; Mullan, Dermott; Schmidt, Sarah J.; Burgasser, Adam J.; Williams, Peter K. G.

    2017-08-01

    We use Kepler K2 Campaign 4 short-cadence (one-minute) photometry to measure white light flares in the young, moving group brown dwarfs 2MASS J03350208+2342356 (2M0335+23) and 2MASS J03552337+1133437 (2M0355+11), and report on long-cadence (thirty-minute) photometry of a superflare in the Pleiades M8 brown dwarf CFHT-PL-17. The rotation period (5.24 hr) and projected rotational velocity (45 km s-1) confirm 2M0335+23 is inflated (R≥slant 0.20 {R}⊙ ) as predicted for a 0.06 {M}⊙ , 24 Myr old brown dwarf βPic moving group member. We detect 22 white light flares on 2M0335+23. The flare frequency distribution follows a power-law distribution with slope -α =-1.8+/- 0.2 over the range 1031 to 1033 erg. This slope is similar to that observed in the Sun and warmer flare stars, and is consistent with lower-energy flares in previous work on M6-M8 very-low-mass stars; taking the two data sets together, the flare frequency distribution for ultracool dwarfs is a power law over 4.3 orders of magnitude. The superflare (2.6× {10}34 erg) on CFHT-PL-17 shows higher-energy flares are possible. We detect no flares down to a limit of 2× {10}30 erg in the nearby L5γ AB Dor moving group brown dwarf 2M0355+11, consistent with the view that fast magnetic reconnection is suppressed in cool atmospheres. We discuss two multi-peaked flares observed in 2M0335+23, and argue that these complex flares can be understood as sympathetic flares, in which fast-mode magnetohydrodynamic waves similar to extreme-ultraviolet waves in the Sun trigger magnetic reconnection in different active regions.

  15. Recurrence or rebound of clinical relapses after discontinuation of natalizumab therapy in highly active MS patients

    Sorensen, P. S.; Koch-Henriksen, N.; Petersen, T.

    2014-01-01

    A number of studies have reported flare-up of multiple sclerosis (MS) disease activity after cessation of natalizumab, increasing to a level beyond the pre-natalizumab treatment level. Our aim was to describe the development in clinical disease activity following cessation of natalizumab therapy...

  16. Multiple forms of endopeptidase activity from jojoba seeds.

    Wolf, M J; Storey, R D

    1990-01-01

    The cotyledons of 27 day post-germination jojoba seedlings (Simmondsia chinensis) contained five distinct endopeptidase activities separable by DEAE Bio-Gel and CM-cellulose ion exchange chromatography. The endopeptidases were purified 108- to 266-fold and their individuality was confirmed by activity-specific assays in native acrylamide gels along with differences in their Mr and catalytic properties. The five endopeptidases, which showed activity on model substrates and protein, were named EP Ia, EP Ib, EP II, EP III and EP IV. EP Ia was a serine proteinase with a pH optimum of ca 8 and Mr of 58,000. EP Ib, II and III were discrete cysteine proteinases showing pH optima of ca 6.8, 6.0 and 5.4 and Mr of 41,000, 47,000 and 35,000 respectively. EP IV was an aspartic acid proteinase with a ca pH optimum of 3.5 and Mr of 33,000.

  17. ACT-Vision: active collaborative tracking for multiple PTZ cameras

    Broaddus, Christopher; Germano, Thomas; Vandervalk, Nicholas; Divakaran, Ajay; Wu, Shunguang; Sawhney, Harpreet

    2009-04-01

    We describe a novel scalable approach for the management of a large number of Pan-Tilt-Zoom (PTZ) cameras deployed outdoors for persistent tracking of humans and vehicles, without resorting to the large fields of view of associated static cameras. Our system, Active Collaborative Tracking - Vision (ACT-Vision), is essentially a real-time operating system that can control hundreds of PTZ cameras to ensure uninterrupted tracking of target objects while maintaining image quality and coverage of all targets using a minimal number of sensors. The system ensures the visibility of targets between PTZ cameras by using criteria such as distance from sensor and occlusion.

  18. Laser flare photometry in clinical practice

    Yury S Astakhov

    2016-06-01

    Full Text Available Laser flare photometry (LFP is the only quantitative and objective method for the evaluation of aqueous flare. There are numerous opportunities to use LFP in clinical practice, and they are discussed in the paper. It is especially helpful in management of uveitis patients, because it allows estimating the correct diagnosis, managing the patient during the treatment with noninvasive method and predicting relapses and complications.

  19. Inferring Human Activity in Mobile Devices by Computing Multiple Contexts.

    Chen, Ruizhi; Chu, Tianxing; Liu, Keqiang; Liu, Jingbin; Chen, Yuwei

    2015-08-28

    This paper introduces a framework for inferring human activities in mobile devices by computing spatial contexts, temporal contexts, spatiotemporal contexts, and user contexts. A spatial context is a significant location that is defined as a geofence, which can be a node associated with a circle, or a polygon; a temporal context contains time-related information that can be e.g., a local time tag, a time difference between geographical locations, or a timespan; a spatiotemporal context is defined as a dwelling length at a particular spatial context; and a user context includes user-related information that can be the user's mobility contexts, environmental contexts, psychological contexts or social contexts. Using the measurements of the built-in sensors and radio signals in mobile devices, we can snapshot a contextual tuple for every second including aforementioned contexts. Giving a contextual tuple, the framework evaluates the posteriori probability of each candidate activity in real-time using a Naïve Bayes classifier. A large dataset containing 710,436 contextual tuples has been recorded for one week from an experiment carried out at Texas A&M University Corpus Christi with three participants. The test results demonstrate that the multi-context solution significantly outperforms the spatial-context-only solution. A classification accuracy of 61.7% is achieved for the spatial-context-only solution, while 88.8% is achieved for the multi-context solution.

  20. Modelling blazar flaring using a time-dependent fluid jet emission model - an explanation for orphan flares and radio lags

    Potter, William J.

    2018-01-01

    Blazar jets are renowned for their rapid violent variability and multiwavelength flares, however, the physical processes responsible for these flares are not well understood. In this paper, we develop a time-dependent inhomogeneous fluid jet emission model for blazars. We model optically thick radio flares for the first time and show that they are delayed with respect to the prompt optically thin emission by ∼months to decades, with a lag that increases with the jet power and observed wavelength. This lag is caused by a combination of the travel time of the flaring plasma to the optically thin radio emitting sections of the jet and the slow rise time of the radio flare. We predict two types of flares: symmetric flares - with the same rise and decay time, which occur for flares whose duration is shorter than both the radiative lifetime and the geometric path-length delay time-scale; extended flares - whose luminosity tracks the power of particle acceleration in the flare, which occur for flares with a duration longer than both the radiative lifetime and geometric delay. Our model naturally produces orphan X-ray and γ-ray flares. These are caused by flares that are only observable above the quiescent jet emission in a narrow band of frequencies. Our model is able to successfully fit to the observed multiwavelength flaring spectra and light curves of PKS1502+106 across all wavelengths, using a transient flaring front located within the broad-line region.

  1. Preliminary Evidence that Self-Efficacy Predicts Physical Activity in Multiple Sclerosis

    Motl, Robert W.; McAuley, Edward; Doerksen, Shawna; Hu, Liang; Morris, Katherine S.

    2009-01-01

    Individuals with multiple sclerosis (MS) are less physically active than nondiseased people. One method for increasing physical activity levels involves the identification of factors that correlate with physical activity and that are modifiable by a well designed intervention. This study examined two types of self-efficacy as cross-sectional and…

  2. HEART RATE AND PHYSICAL ACTIVITY PATTERNS IN PERSONS WITH PROFOUND INTELLECTUAL AND MULTIPLE DISABILITIES

    Waninge, Aly; van der Putten, Annette A. J.; Stewart, Roy E.; Steenbergen, Bert; van Wijck, Ruud; van der Schans, Cees P.

    2013-01-01

    Because physical fitness and health are related to physical activity, it is important to gain an insight into the physical activity levels of persons with profound intellectual and multiple disabilities (PIMD). The purpose of this study was to examine heart rate patterns to measure the activity

  3. ARCADE IMPLOSION CAUSED BY A FILAMENT ERUPTION IN A FLARE

    Wang, Juntao; Simões, P. J. A.; Fletcher, L.; Hannah, I. G. [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Thalmann, J. K. [Institute of Physics/IGAM, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Hudson, H. S., E-mail: j.wang.4@research.gla.ac.uk [SSL/UC, Berkeley, CA (United States)

    2016-12-20

    Coronal implosions—the convergence motion of plasmas and entrained magnetic field in the corona due to a reduction in magnetic pressure—can help to locate and track sites of magnetic energy release or redistribution during solar flares and eruptions. We report here on the analysis of a well-observed implosion in the form of an arcade contraction associated with a filament eruption, during the C3.5 flare SOL2013-06-19T07:29. A sequence of events including the magnetic flux-rope instability and distortion, followed by a filament eruption and arcade implosion, lead us to conclude that the implosion arises from the transfer of magnetic energy from beneath the arcade as part of the global magnetic instability, rather than due to local magnetic energy dissipation in the flare. The observed net contraction of the imploding loops, which is found also in nonlinear force-free field extrapolations, reflects a permanent reduction of magnetic energy underneath the arcade. This event shows that, in addition to resulting in the expansion or eruption of an overlying field, flux-rope instability can also simultaneously implode an unopened field due to magnetic energy transfer. It demonstrates the “partial opening of the field” scenario, which is one of the ways in 3D to produce a magnetic eruption without violating the Aly–Sturrock hypothesis. In the framework of this observation, we also propose a unification of three main concepts for active region magnetic evolution, namely the metastable eruption model, the implosion conjecture, and the standard “CSHKP” flare model.

  4. Whole-Body MRI versus PET in assessment of multiple myeloma disease activity.

    Shortt, Conor P

    2009-04-01

    The purpose of this study was to compare FDG PET; whole-body MRI; and the reference standard, bone marrow aspiration and biopsy, to determine the best imaging technique for assessment of disease activity in multiple myeloma.

  5. Memory impairment in multiple sclerosis: Relevance of hippocampal activation and hippocampal connectivity

    Hulst, H.E.; Schoonheim, M.M.; van Geest, Q.; Uitdehaag, B.M.J.; Barkhof, F.; Geurts, J.J.G.

    2015-01-01

    Background: Memory impairment is frequent in multiple sclerosis (MS), but it is unclear what functional brain changes underlie this cognitive deterioration. Objective: To investigate functional hippocampal activation and connectivity, in relation to memory performance in MS. Methods: Structural and

  6. Solar and stellar flares and their impact on planets

    Shibata, Kazunari

    Recent observations of the Sun revealed that the solar atmosphere is full of flares and flare-like phenomena, which affect terrestrial environment and our civilization. It has been established that flares are caused by the release of magnetic energy through magnetic reconnection. Many stars show flares similar to solar flares, and such stellar flares especially in stars with fast rotation are much more energetic than solar flares. These are called superflares. The total energy of a solar flare is 1029 - 1032 erg, while that of a superflare is 1033 - 1038 erg. Recently, it was found that superflares (with 1034 - 1035 erg) occur on Sun-like stars with slow rotation with frequency once in 800 - 5000 years. This suggests the possibility of superflares on the Sun. We review recent development of solar and stellar flare research, and briefly discuss possible impacts of superflares on the Earth and exoplanets.

  7. Effect of flow parameters on flare stack generator noise

    Dinn, T.S.

    1998-01-01

    The SoundPLAN Computer Noise Model was used to determine the general effect of flare noise in a community adjacent to a petrochemical plant. Tests were conducted to determine the effect of process flow conditions and the pulsating flame on the flare stack generator noise from both a refinery flare and process flare. Flaring under normal plant operations, the flaring of fuel gas and the flaring of hydrogen were the three conditions that were tested. It was shown that the steam flow rate was the determining factor in the flare stack generated noise. Variations in the water seal level in the flare line surge tank increased or decreased the gas flowrate, which resulted in a pulsating flame. The period and amplitude of the pulsating noise from the flare stacks was determined by measuring several parameters. Flare stack noise oscillations were found to be greater for the process flare than for the refinery flare stack. It was suggested that minimizing the amount of steam fed to the flare and improving the burner design would minimize noise. 2 tabs., 6 figs

  8. Contribution of Tula Refinery flaring emissions to the Mexico megacity

    Almanza, Victor; Molina, Luisa; Sosa, Gustavo

    2013-04-01

    ), mean bias (BIAS), vector RMSE and Index of Agreement (IOA). WRF-Chem outputs of SO2 and soot are compared with surface measurements obtained at the three supersites of MILAGRO campaign. Results suggest a contribution of Tula flaring activities to the total SO2 levels at the urban supersite (T0) of 37 %, and of 39 % at the suburban supersite (T1). In the MCMA, modeled SO2 is compared with representative monitoring stations of the MCMA Monitoring Network (RAMA). The suggested contribution is about 43 % and 36 % at the north and south regions of the basin respectively. As for soot, results indicate low contribution at the three supersites, with less than 0.1% at three supersites. According to the model, the greatest contribution of Tula flaring emissions to the three supersites and the MCMA basin occurred on 23 March, which coincided with the third cold surge event reported during the campaign.

  9. The size of coronal hard X-ray sources in solar flares: How big are they?

    Effenberger, F.; Krucker, S.; Rubio da Costa, F.

    2017-12-01

    Coronal hard X-ray sources are considered to be one of the key signatures of non-thermal particle acceleration and heating during the energy release in solar flares. In some cases, X-ray observations reveal multiple components spatially located near and above the loop top and even further up in the corona. Here, we combine a detailed RHESSI imaging analysis of near-limb solar flares with occulted footpoints and a multi-wavelength study of the flare loop evolution in SDO/AIA. We connect our findings to different current sheet formation and magnetic break-out scenarios and relate it to particle acceleration theory. We find that the upper and usually fainter emission regions can be underestimated in their size due to the majority of flux originating from the lower loops.

  10. The CME Flare Arcade and the Width of the CME in the Outer Corona

    Moore, Ron; Falconer, David; Sterling, Alphonse

    2008-01-01

    Moore, Sterling, & Suess (2007, ApJ, 668, 1221) present evidence that (1) a CME is typically a magnetic bubble, a low-beta gplasmoid with legs h having roughly the 3D shape of a light bulb, and (2) in the outer corona the CME plasmoid is in lateral pressure equilibrium with the ambient magnetic field. They present three CMEs observed by SOHO/LASCO, each from a very different source located near the limb. One of these CMEs came from a compact ejective eruption from a small part of a sunspot active region, another came from a large quiet-region filament eruption, and the third CME, an extremely large and fast one, was produced in tandem with an X20 flare arcade that was centered on a huge delta sunspot. Each of these CMEs had more or less the classic lightbulb silhouette and attained a constant heliocentric angular width in the outer corona. This indicates that the CME plasmoid attained lateral magnetic pressure balance with the ambient radial magnetic field in the outer corona. This lateral pressure balance, together with the standard scenario for CME production by the eruption of a sheared-core magnetic arcade, yields the following simple estimate of the strength B(sub Flare) of the magnetic field in the flare arcade produced together with the CME: B(sub Flare) 1.4(theta CME/theta Flare)sup 2 G, where theta (sub CME) is the heliocentric angular width of the CME plasmoid in the outer corona and theta (sub Flare) is the heliocentric angular width of the full-grown flare arcade. Conversely, theta (sub CME) approximately equal to (R(sub Sun)sup -1(phi(sub Flare)/1.4)sup 1/2 radians, where Flare is the magnetic flux covered by the full-grown flare arcade. In addition to presenting the three CMEs of Moore, Sterling, & Suess (2007) and their agreement with this relation between CME and Flare, we present a further empirical test of this relation. For CMEs that erupt from active regions, the co-produced flare arcade seldom if ever covers the entire active region: if AR is

  11. Feasibility of flare gas reformation to practical energy in Farashband gas refinery: no gas flaring.

    Rahimpour, Mohammad Reaza; Jokar, Seyyed Mohammad

    2012-03-30

    A suggested method for controlling the level of hazardous materials in the atmosphere is prevention of combustion in flare. In this work, three methods are proposed to recover flare gas instead of conventional gas-burning in flare at the Farashband gas refinery. These methods aim to minimize environmental and economical disadvantages of burning flare gas. The proposed methods are: (1) gas to liquid (GTL) production, (2) electricity generation with a gas turbine and, (3) compression and injection into the refinery pipelines. To find the most suitable method, the refinery units that send gas to the flare as well as the required equipment for the three aforementioned methods are simulated. These simulations determine the amount of flare gas, the number of GTL barrels, the power generated by the gas turbine and the required compression horsepower. The results of simulation show that 563 barrels/day of valuable GTL products is produced by the first method. The second method provides 25 MW electricity and the third method provides a compressed natural gas with 129 bar pressure for injection to the refinery pipelines. In addition, the economics of flare gas recovery methods are studied and compared. The results show that for the 4.176MMSCFD of gas flared from the Farashband gas refinery, the electricity production gives the highest rate of return (ROR), the lowest payback period, the highest annual profit and mild capital investment. Therefore, the electricity production is the superior method economically. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Self-Care Activities among People with Multiple Sclerosis in Denmark

    Lynning, Marie; Hanehøj, Kirsten; Karnøe Knudsen, Astrid

    2017-01-01

    Background: People with multiple sclerosis (PwMS) are known to use a wide range of medical and non-medical treatments. This study aims at investigating the use of self-care activities within this patient group. Material and Methods: The study follows a descriptive cross-sectional design based...... on an online survey among members of the Danish Multiple Sclerosis Society's permanent respondent panel. Results: The results of the study indicate that the respondents carry out a wide variety of self-care activities. These activities comprise conventional activities as well as complementary and alternative...

  13. The interpretation of physical activity, exercise, and sedentary behaviours by persons with multiple sclerosis.

    Kinnett-Hopkins, Dominique; Learmonth, Yvonne; Hubbard, Elizabeth; Pilutti, Lara; Roberts, Sarah; Fanning, Jason; Wójcicki, Thomas; McAuley, Edward; Motl, Robert

    2017-11-07

    This study adopted a qualitative research design with directed content analysis and examined the interpretations of physical activity, exercise, and sedentary behaviour by persons with multiple sclerosis. Fifty three persons with multiple sclerosis who were enrolled in an exercise trial took part in semi-structured interviews regarding personal interpretations of physical activity, exercise, and sedentary behaviours. Forty three percent of participants indicated a consistent understanding of physical activity, 42% of participants indicated a consistent understanding of exercise, and 83% of participants indicated a consistent understanding of sedentary behaviour with the standard definitions. There was evidence of definitional ambiguity (i.e., 57, 58, and 11% of the sample for physical activity, exercise, and sedentary behaviour, respectively); 6% of the sample inconsistently defined sedentary behaviour with standard definitions. Some participants described physical activity in a manner that more closely aligned with exercise and confused sedentary behaviour with exercise or sleeping/napping. Results highlight the need to provide and utilise consistent definitions for accurate understanding, proper evaluation and communication of physical activity, exercise, and sedentary behaviours among persons with multiple sclerosis. The application of consistent definitions may minimise ambiguity, alleviate the equivocality of findings in the literature, and translate into improved communication about these behaviours in multiple sclerosis. Implications for Rehabilitation The symptoms of multiple sclerosis can be managed through participation in physical activity and exercise. Persons with multiple sclerosis are not engaging in sufficient levels of physical activity and exercise for health benefits. Rehabilitation professionals should use established definitions of physical activity, exercise, and sedentary behaviours when communicating about these behaviours among persons with

  14. Toward an Efficient Prediction of Solar Flares: Which Parameters, and How?

    Manolis K. Georgoulis

    2013-11-01

    Full Text Available Solar flare prediction has become a forefront topic in contemporary solar physics, with numerous published methods relying on numerous predictive parameters, that can even be divided into parameter classes. Attempting further insight, we focus on two popular classes of flare-predictive parameters, namely multiscale (i.e., fractal and multifractal and proxy (i.e., morphological parameters, and we complement our analysis with a study of the predictive capability of fundamental physical parameters (i.e., magnetic free energy and relative magnetic helicity. Rather than applying the studied parameters to a comprehensive statistical sample of flaring and non-flaring active regions, that was the subject of our previous studies, the novelty of this work is their application to an exceptionally long and high-cadence time series of the intensely eruptive National Oceanic and Atmospheric Administration (NOAA active region (AR 11158, observed by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. Aiming for a detailed study of the temporal evolution of each parameter, we seek distinctive patterns that could be associated with the four largest flares in the AR in the course of its five-day observing interval. We find that proxy parameters only tend to show preflare impulses that are practical enough to warrant subsequent investigation with sufficient statistics. Combining these findings with previous results, we conclude that: (i carefully constructed, physically intuitive proxy parameters may be our best asset toward an efficient future flare-forecasting; and (ii the time series of promising parameters may be as important as their instantaneous values. Value-based prediction is the only approach followed so far. Our results call for novel signal and/or image processing techniques to efficiently utilize combined amplitude and temporal-profile information to optimize the inferred solar-flare probabilities.

  15. FACT. Flare alerts from blazar monitoring

    Dorner, Daniela [Universitaet Wuerzburg (Germany); Bretz, Thomas [RWTH Aachen (Germany); Collaboration: FACT-Collaboration

    2015-07-01

    One of the major goals of the First G-APD Cherenkov Telescope is the longterm monitoring of bright TeV blazars. For more than three years, FACT has observed the blazars Mrk 421 and Mrk 501 and a few other sources on a regular basis. To understand these highly variable objects, simultaneous data at different wavelengths are very useful. FACT is not only taking part in multi-wavelength campaigns, but also sending alerts to other instruments in case of enhanced flux, to study flares within the multi-wavelength frame. To send fast alerts, an automatic quick look analysis was set up on site. Once the data are written on disk, they are automatically processed, and the analysis results are published on a website where other observers can monitor the activity of the source in the very high energy band. In addition, alerts are sent in case the flux is higher than a certain predefined value. In 2014, more than five alerts have been sent. Results from three years of monitoring are presented.

  16. Optical flare observed in the flaring gamma-ray blazar CGRaBS J0809+5341 (87GB 080551.6+535010)

    Pursimo, Tapio; Galindo-Guil, F. J.; Serrano, Pere Blay; Ojha, Roopesh

    2017-11-01

    We report optical photometry of the blazar CGRaBS J0809+5341 (87GB 080551.6+535010), obtained with the 2.56m Nordic Optical Telescope in La Palma, to look for any enhanced optical activity associated with a recent flare in the daily averaged gamma-ray flux (ATel#10905).

  17. DMPD: Multiple signaling pathways leading to the activation of interferon regulatoryfactor 3. [Dynamic Macrophage Pathway CSML Database

    Full Text Available 12213596 Multiple signaling pathways leading to the activation of interferon regula...(.html) (.csml) Show Multiple signaling pathways leading to the activation of interferon regulatoryfactor 3.... PubmedID 12213596 Title Multiple signaling pathways leading to the activation of

  18. Application of Convolution Neural Network to the forecasts of flare classification and occurrence using SOHO MDI data

    Park, Eunsu; Moon, Yong-Jae

    2017-08-01

    A Convolutional Neural Network(CNN) is one of the well-known deep-learning methods in image processing and computer vision area. In this study, we apply CNN to two kinds of flare forecasting models: flare classification and occurrence. For this, we consider several pre-trained models (e.g., AlexNet, GoogLeNet, and ResNet) and customize them by changing several options such as the number of layers, activation function, and optimizer. Our inputs are the same number of SOHO)/MDI images for each flare class (None, C, M and X) at 00:00 UT from Jan 1996 to Dec 2010 (total 1600 images). Outputs are the results of daily flare forecasting for flare class and occurrence. We build, train, and test the models on TensorFlow, which is well-known machine learning software library developed by Google. Our major results from this study are as follows. First, most of the models have accuracies more than 0.7. Second, ResNet developed by Microsoft has the best accuracies : 0.86 for flare classification and 0.84 for flare occurrence. Third, the accuracies of these models vary greatly with changing parameters. We discuss several possibilities to improve the models.

  19. Global energetics of solar flares. I. Magnetic energies

    Aschwanden, Markus J. [Lockheed Martin, Solar and Astrophysics Laboratory, Org. A021S, Bldg. 252, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Xu, Yan; Jing, Ju, E-mail: aschwanden@lmsal.com, E-mail: yan.xu@njit.edu, E-mail: ju.jing@njit.edu [Space Weather Research Laboratory, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, Newark, NJ 07102-1982 (United States)

    2014-12-10

    We present the first part of a project on the global energetics of solar flares and coronal mass ejections that includes about 400 M- and X-class flares observed with Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). We calculate the potential (E{sub p} ), the nonpotential (E {sub np}) or free energies (E {sub free} = E {sub np} – E{sub p} ), and the flare-dissipated magnetic energies (E {sub diss}). We calculate these magnetic parameters using two different NLFFF codes: the COR-NLFFF code uses the line-of-sight magnetic field component B{sub z} from HMI to define the potential field, and the two-dimensional (2D) coordinates of automatically detected coronal loops in six coronal wavelengths from AIA to measure the helical twist of coronal loops caused by vertical currents, while the PHOT-NLFFF code extrapolates the photospheric three-dimensional (3D) vector fields. We find agreement between the two codes in the measurement of free energies and dissipated energies within a factor of ≲ 3. The size distributions of magnetic parameters exhibit powerlaw slopes that are approximately consistent with the fractal-diffusive self-organized criticality model. The magnetic parameters exhibit scaling laws for the nonpotential energy, E{sub np}∝E{sub p}{sup 1.02}, for the free energy, E{sub free}∝E{sub p}{sup 1.7} and E{sub free}∝B{sub φ}{sup 1.0}L{sup 1.5}, for the dissipated energy, E{sub diss}∝E{sub p}{sup 1.6} and E{sub diss}∝E{sub free}{sup 0.9}, and the energy dissipation volume, V∝E{sub diss}{sup 1.2}. The potential energies vary in the range of E{sub p} = 1 × 10{sup 31}-4 × 10{sup 33} erg, while the free energy has a ratio of E {sub free}/E{sub p} ≈ 1%-25%. The Poynting flux amounts to F {sub flare} ≈ 5 × 10{sup 8}-10{sup 10} erg cm{sup –2} s{sup –1} during flares, which averages to F {sub AR} ≈ 6 × 10{sup 6} erg cm{sup –2} s{sup –1} during the entire observation

  20. Telephone-Based Physical Activity Counseling for Major Depression in People with Multiple Sclerosis

    Bombardier, Charles H.; Ehde, Dawn M.; Gibbons, Laura E.; Wadhwani, Roini; Sullivan, Mark D.; Rosenberg, Dori E.; Kraft, George H.

    2013-01-01

    Objective: Physical activity represents a promising treatment for major depressive disorder (MDD) in people with multiple sclerosis (MS). We conducted a single-blind, two-arm randomized controlled trial comparing a 12-week physical activity counseling intervention delivered primarily by telephone (n = 44) to a wait-list control group (N = 48).…

  1. Coronary Heart Disease Risk between Active and Inactive Women with Multiple Sclerosis.

    Slawta, Jennifer N.; McCubbin, Jeffrey A.; Wilcox, Anthony R.; Fox, Susan D.; Nalle, Darek J.; Anderson, Gail

    2002-01-01

    Investigated whether abdominal fat accumulation and levels of triglyceride, high-density lipoprotein cholesterol, and glucose differed between 123 active and inactive women with multiple sclerosis (MS). Results indicated that low-to-moderate leisure time physical activity significantly related to less abdominal fat accumulation, lower triglyceride…

  2. Social Cognitive Correlates of Physical Activity in Inactive Adults with Multiple Sclerosis

    Dlugonski, Deirdre; Wojcicki, Thomas R.; McAuley, Edward; Motl, Robert W.

    2011-01-01

    Persons with multiple sclerosis (MS) are often physically inactive. This observation has prompted the search for modifiable constructs derived from established theories that act as correlates of physical activity. This study investigated self efficacy, outcome expectations, impediments, and goal setting as correlates of physical activity in…

  3. Radio-flaring Ultracool Dwarf Population Synthesis

    Route, Matthew, E-mail: mroute@purdue.edu [Department of Astronomy and Astrophysics, the Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

    2017-08-10

    Over a dozen ultracool dwarfs (UCDs), low-mass objects of spectral types ≥M7, are known to be sources of radio flares. These typically several-minutes-long radio bursts can be up to 100% circularly polarized and have high brightness temperatures, consistent with coherent emission via the electron cyclotron maser operating in approximately kilogauss magnetic fields. Recently, the statistical properties of the bulk physical parameters that describe these UCDs have become described adequately enough to permit synthesis of the population of radio-flaring objects. For the first time, I construct a Monte Carlo simulator to model the population of these radio-flaring UCDs. This simulator is powered by Intel Secure Key (ISK), a new processor technology that uses a local entropy source to improve random number generation that has heretofore been used to improve cryptography. The results from this simulator indicate that only ∼5% of radio-flaring UCDs within the local interstellar neighborhood (<25 pc away) have been discovered. I discuss a number of scenarios that may explain this radio-flaring fraction and suggest that the observed behavior is likely a result of several factors. The performance of ISK as compared to other pseudorandom number generators is also evaluated, and its potential utility for other astrophysical codes is briefly described.

  4. Numerical simulation of a sour gas flare

    Chambers, A. [Alberta Research Council, Devon, AB (Canada)

    2008-07-01

    Due to the limited amount of information in the literature on sour gas flares and the cost of conducting wind tunnel and field experiments on sour flares, this presentation presented a modelling project that predicted the effect of operating conditions on flare performance and emissions. The objectives of the project were to adapt an existing numerical model suitable for flare simulation, incorporate sulfur chemistry, and run simulations for a range of conditions typical of sour flares in Alberta. The study involved the use of modelling expertise at the University of Utah, and employed large eddy simulation (LES) methods to model open flames. The existing model included the prediction of turbulent flow field; hydrocarbon reaction chemistry; soot formation; and radiation heat transfer. The presentation addressed the unique features of the model and discussed whether LES could predict the flow field. Other topics that were presented included the results from a University of Utah comparison; challenges of the LES model; an example of a run time issue; predicting the impact of operating conditions; and the results of simulations. Last, several next steps were identified and preliminary results were provided. Future work will focus on reducing computation time and increasing information reporting. figs.

  5. INITIATION PROCESSES FOR THE 2013 MAY 13 X1.7 LIMB FLARE

    Shen, Jinhua; Wang, Ya; Zhou, Tuanhui; Ji, Haisheng

    2017-01-01

    For the X1.7 class flare on 2013 May 13 (SOL2013-05-13T01:53), its initiation process was well observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory and the Extreme UltraViolet Imager (EUVI) on board STEREO-B . The initiation process incorporates the following phenomena: an X-ray precursor that started ∼9 minutes before flare onset, two hot magnetic loops (as seen with AIA hot channels) forming a sigmoidal core magnetic structure (as seen with the EUVI), a rapidly formed magnetic flux rope (MFR) that expands outward, and a flare loop that contracts inward. The two hot magnetic loops were activated after the occurrence of the X-ray precursor. After activation, magnetic reconnection occurred between the two hot magnetic loops (inside the sigmoid structure), which produced the expanding MFR and the contracting flare loop (CFL). The MFR and CFL can only be seen with AIA hot and cool channels, respectively. For this flare, the real initiation time can be regarded as being from the starting time of the precursor, and its impulsive phase started when the MFR began its fast expansion. In addition, the CFL and the growing postflare magnetic loops are different loop systems, and the CFL was the product of magnetic reconnection between sheared magnetic fields that also produced the MFR.

  6. INITIATION PROCESSES FOR THE 2013 MAY 13 X1.7 LIMB FLARE

    Shen, Jinhua [Xinjiang Astronomical Observatory, CAS, 830011, Urumqi (China); Wang, Ya; Zhou, Tuanhui; Ji, Haisheng, E-mail: jihs@pmo.ac.cn [Purple Mountain Observatory, CAS, Nanjing, 210008 (China)

    2017-01-20

    For the X1.7 class flare on 2013 May 13 (SOL2013-05-13T01:53), its initiation process was well observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory and the Extreme UltraViolet Imager (EUVI) on board STEREO-B . The initiation process incorporates the following phenomena: an X-ray precursor that started ∼9 minutes before flare onset, two hot magnetic loops (as seen with AIA hot channels) forming a sigmoidal core magnetic structure (as seen with the EUVI), a rapidly formed magnetic flux rope (MFR) that expands outward, and a flare loop that contracts inward. The two hot magnetic loops were activated after the occurrence of the X-ray precursor. After activation, magnetic reconnection occurred between the two hot magnetic loops (inside the sigmoid structure), which produced the expanding MFR and the contracting flare loop (CFL). The MFR and CFL can only be seen with AIA hot and cool channels, respectively. For this flare, the real initiation time can be regarded as being from the starting time of the precursor, and its impulsive phase started when the MFR began its fast expansion. In addition, the CFL and the growing postflare magnetic loops are different loop systems, and the CFL was the product of magnetic reconnection between sheared magnetic fields that also produced the MFR.

  7. What is the Relationship Between the Properties of Photospheric Flows and Flares?

    Welsch, Brian; Li, Y.; Schuck, P. W.; Fisher, G. H.

    2009-05-01

    We estimated photospheric velocities by separately applying the Fourier Local Correlation Tracking (FLCT) and Differential Affine Velocity Estimator (DAVE) methods to 2708 co-registered pairs of SOHO/MDI magnetograms, with nominal 96-minute cadence, from 46 active regions (ARs) from 1996-1998 over the time interval κ45 when each AR was within 45° of disk center. For each magnetogram pair, we computed the average estimated radial magnetic field, BR and each tracking method produced an independently estimated flow field, u. We then quantitatively characterized these magnetic and flow fields by computing several extrinsic and intrinsic properties of each; extrinsic properties scale with AR size, while intrinsic properties do not depend directly on AR size. Intrinsic flow properties included moments of speeds, horizontal divergences, and radial curls; extrinsic flow properties included included sums of these properties, and a crude proxy for the ideal Poynting flux, ∑ |u| BR2. Several quantities derived from BR were also computed, including: total unsigned flux, Φ a measure of the amount of unsigned flux near strong-field polarity inversion lines (SPILs), R and ∑ BR2. Next, using correlation and discriminant analysis, we investigated the associations between derived properties and average flare flux determined from the GOES flare catalog, when averaged over both κ45 and shorter time windows, of 6 and 24 hours. Our AR sample included both flaring and flare-quiet ARs; the latter did not flare above GOES C1.0 level during κ45. Among magnetic properties, we found R to be most strongly associated with flare flux. Among extrinsic flow properties, the proxy Poynting flux, ∑ |u| BR2, was most strongly associated with flux, at a level comparable to that of R. All intrinsic flow properties studied were more poorly associated with flare flux than these magnetic properties.

  8. Statistics and Classification of the Microwave Zebra Patterns Associated with Solar Flares

    Tan, B.-L.; Tan, C.M.; Zhang, Y.; Mészárosová, Hana; Karlický, Marian

    2014-01-01

    Roč. 780, č. 2 (2014), 129/1-129/9 ISSN 0004-637X R&D Projects: GA ČR GAP209/12/0103 Institutional support: RVO:67985815 Keywords : Sun activity * activity * flares Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.993, year: 2014

  9. A study of flare stars in the taurus region

    Khodzhaev, A.S.

    1986-01-01

    The results are given of a search for flare stars in the region of the dark clouds in Taurus together with the results of photometric, H /sub alpha/ -spectroscopic, and statistical investigations of them. Photographic observations during 1980-1984 revealed 92 new flare stars, 13 of which were found to be known Orion variables with 16 repeated flares of 13 previously known flare stars. Their apparent distribution is considered. The question of whether the flare stars belong to a dark cloud is discussed. A comparative analysis of the flare stars in the Taurus region and other aggregates is made. The Hertzsprung-Russell (V, B - V) and two-color (U - B, B - V) diagrams for the flare stars are similar to the corresponding diagrams constructed for star clusters and associations (Pleiades, Orion, etc.). The total number of flare stars in the region of the dark clouds in Taurus is estimated at ≥ 500

  10. Gas Flaring: Carbon dioxide Contribution to Global Warming ...

    PROF HORSFALL

    emissions resulting from high consumption of fossil fuels. Flaring been a ... method of analysis showed that carbon dioxide from gas flaring constitute 1% of the total ... Although of these, methane is potentially the most .... in some gas plants.

  11. Frequency distribution function of stellar flares in the Orion association

    Parsamian, E.S.

    1981-01-01

    The temporal distributions of flare stars in the Orion association and the numbers of stars with different flare frequencies are determined by means of Ambartsumian's (1978) method, which uses the chronology of discovery of 'first' flares and the chronology of confirmations, i.e., the temporal distributions of 'repeated' flares. It is shown that flare stars with high flare frequency (not greater than 1000 hours) in the Pleiades are basically stars of low luminosity with M(U) not less than 13m. Two independent methods of determining the number of flare stars in the aggregates confirm that there are about 1.5 times more flare stars in the Orion association than in the Pleiades

  12. Solar flare loops observations and interpretations

    Huang, Guangli; Ji, Haisheng; Ning, Zongjun

    2018-01-01

    This book provides results of analysis of typical solar events, statistical analysis, the diagnostics of energetic electrons and magnetic field, as well as the global behavior of solar flaring loops such as their contraction and expansion. It pays particular attention to analyzing solar flare loops with microwave, hard X-ray, optical and EUV emissions, as well as the theories of their radiation, and electron acceleration/transport. The results concerning influence of the pitch-angle anisotropy of non-thermal electrons on their microwave and hard X-ray emissions, new spectral behaviors in X-ray and microwave bands, and results related to the contraction of flaring loops, are widely discussed in the literature of solar physics. The book is useful for graduate students and researchers in solar and space physics.

  13. Endodontic flare-ups: a prospective study.

    Alves, Vanessa de Oliveira

    2010-11-01

    The objective of this prospective clinical study was to evaluate the incidence of flare-ups (pain and/or swelling requiring endodontic interappointment and emergency treatment) and identify the risk factors associated with their occurrence in patients who received endodontic treatment from June 2006 to June 2007 at the endodontics clinic of the São Paulo Dental Association (APCD), Jardim Paulista branch, São Paulo, Brazil. The incidence of flare-ups was 1.71% out of 408 teeth that had received endodontic therapy. Statistical analysis using the chi-squared test (P flare-up rate and the presence of a periradicular radiolucency. Copyright © 2010 Mosby, Inc. All rights reserved.

  14. Multiple co morbid conditions in patient with Mast Cell Activation Syndrome

    2017-10-26

    conditions in patient \\\\·ith Mast Cell Activation Syndron1e Sb. GRANT NUMBER Sc. PROGRAM.ELEMENT NUMBER 6. AUTHOR(S) Sd. PROJECT NUMBER Maj Sofia...13. SUPPLEMENTARY NOTES 14. ABSTRACT Multiple co-n1orhid conditions in patient \\Vith Mast Cell Activation Syndrotne Sofia M. Szari.MD. and James...Defense. !NTR()D{JCT!ON: Mast cell activation disorders {MCAD) have been associated \\Vilh Connective Tissue Disorders (CTD) and orthostatic

  15. The kinesin spindle protein inhibitor filanesib enhances the activity of pomalidomide and dexamethasone in multiple myeloma

    Hernández-García, Susana; San-Segundo, Laura; González-Méndez, Lorena; Corchete, Luis A; Misiewicz-Krzeminska, Irena; Martín-Sánchez, Montserrat; López-Iglesias, Ana-Alicia; Algarín, Esperanza Macarena; Mogollón, Pedro; Díaz-Tejedor, Andrea; Paíno, Teresa; Tunquist, Brian; Mateos, María-Victoria; Gutiérrez, Norma C; Díaz-Rodriguez, Elena

    2017-01-01

    [EN]Kinesin spindle protein inhibition is known to be an effective therapeutic approach in several malignancies. Filanesib (ARRY-520), an inhibitor of this protein, has demonstrated activity in heavily pre-treated multiple myeloma patients. The aim of the work herein was to investigate the activity of filanesib in combination with pomalidomide plus dexamethasone backbone, and the mechanisms underlying the potential synergistic effect. The ability of filanesib to enhance the activity of pomali...

  16. The Importance of Providing Multiple-Channel Sections in Dredging Activities to Improve Fish Habitat Environments

    Hung-Pin Chiu

    2016-01-01

    Full Text Available After Typhoon Morakot, dredging engineering was conducted while taking the safety of humans and structures into consideration, but partial stream reaches were formed in the multiple-channel sections in Cishan Stream because of anthropogenic and natural influences. This study mainly explores the distribution of each fish species in both the multiple- and single-channel sections in the Cishan Stream. Parts of the environments did not exhibit significant differences according to a one-way ANOVA comparing the multiple- and single-channel sections, but certain areas of the multiple-channel sections had more diverse habitats. Each fish species was widely distributed by non-metric multidimensional scaling in the multiple-channel sections as compared to those in the single-channel sections. In addition, according to the principal component analysis, each fish species has a preferred environment, and all of them have a wide choice of habitat environments in the multiple-channel sections. Finally, the existence of multiple-channel sections could significantly affect the existence of the fish species under consideration in this study. However, no environmental factors were found to have an influence on fish species in the single-channel sections, with the exception of Rhinogobius nantaiensis. The results show that providing multiple-channel sections in dredging activities could improve fish habitat environments.

  17. THE IMPLICATIONS OF M DWARF FLARES ON THE DETECTION AND CHARACTERIZATION OF EXOPLANETS AT INFRARED WAVELENGTHS

    Tofflemire, Benjamin M.; Wisniewski, John P.; Kowalski, Adam F.; Schmidt, Sarah J.; Kundurthy, Praveen; Hilton, Eric J.; Hawley, Suzanne L.; Holtzman, Jon A.

    2012-01-01

    We present the results of an observational campaign which obtained high-cadence, high-precision, simultaneous optical and IR photometric observations of three M dwarf flare stars for 47 hr. The campaign was designed to characterize the behavior of energetic flare events, which routinely occur on M dwarfs, at IR wavelengths to millimagnitude precision, and quantify to what extent such events might influence current and future efforts to detect and characterize extrasolar planets surrounding these stars. We detected and characterized four highly energetic optical flares having U-band total energies of ∼7.8 × 10 30 to ∼1.3 × 10 32 erg, and found no corresponding response in the J, H, or Ks bandpasses at the precision of our data. For active dM3e stars, we find that a ∼1.3 × 10 32 erg U-band flare (ΔU max ∼ 1.5 mag) will induce 31 erg U-band flare (ΔU max ∼ 1.6 mag) will induce <7.8 (J), <8.8 (H), and <5.1 (Ks) mmag of a response. A flare of this energy or greater should occur less than once per 10 hr. No evidence of stellar variability not associated with discrete flare events was observed at the level of ∼3.9 mmag over 1 hr timescales and at the level of ∼5.6 mmag over 7.5 hr timescales. We therefore demonstrate that most M dwarf stellar activity and flares will not influence IR detection and characterization studies of M dwarf exoplanets above the level of ∼5-11 mmag, depending on the filter and spectral type. We speculate that the most energetic megaflares on M dwarfs, which occur at rates of once per month, are likely to be easily detected in IR observations with sensitivity of tens of millimagnitudes. We also discuss how recent detections of line flux enhancements during M dwarf flares could influence IR transmission spectroscopic observations of M dwarf exoplanets.

  18. Two-phase Heating in Flaring Loops

    Zhu, Chunming; Qiu, Jiong; Longcope, Dana W.

    2018-03-01

    We analyze and model a C5.7 two-ribbon solar flare observed by the Solar Dynamics Observatory, Hinode, and GOES on 2011 December 26. The flare is made of many loops formed and heated successively over one and half hours, and their footpoints are brightened in the UV 1600 Å before enhanced soft X-ray and EUV missions are observed in flare loops. Assuming that anchored at each brightened UV pixel is a half flaring loop, we identify more than 6700 half flaring loops, and infer the heating rate of each loop from the UV light curve at the footpoint. In each half loop, the heating rate consists of two phases: intense impulsive heating followed by a low-rate heating that is persistent for more than 20 minutes. Using these heating rates, we simulate the evolution of their coronal temperatures and densities with the model of the “enthalpy-based thermal evolution of loops.” In the model, suppression of thermal conduction is also considered. This model successfully reproduces total soft X-ray and EUV light curves observed in 15 passbands by four instruments GOES, AIA, XRT, and EVE. In this flare, a total energy of 4.9 × 1030 erg is required to heat the corona, around 40% of this energy is in the slow-heating phase. About two-fifths of the total energy used to heat the corona is radiated by the coronal plasmas, and the other three fifth transported to the lower atmosphere by thermal conduction.

  19. An essay on sunspots and solar flares

    Akasofu, S.-I.

    1984-01-01

    The presently prevailing theories of sunspots and solar flares rely on the hypothetical presence of magnetic flux tubes beneath the photosphere and the two subsequent hypotheses, their emergence above the photosphere and explosive magnetic reconnection, converting magnetic energy carried by the flux tubes for solar flare energy. In this paper, attention is paid to the fact that there are large-scale magnetic fields which divide the photosphere into positive and negative (line-of-sight) polarity regions and that they are likely to be more fundamental than sunspot fields, as emphasized most recently by McIntosh. A new phenomenological model of the sunspot pair formation is then constructed by considering an amplification process of these large-scale fields near their boundaries by shear flows, including localized vortex motions. The amplification results from a dynamo process associated with such vortex flows and the associated convergence flow in the large-scale fields. This dynamo process generates also some of the familiar ''force-free'' fields or the ''sheared'' magnetic fields in which the magnetic field-aligned currents are essential. Upward field-aligned currents generated by the dynamo process are carried by downward streaming electrons which are expected to be accelerated by an electric potential structure; a similar structure is responsible for accelerating auroral electrons in the magnetosphere. Depending on the magnetic field configuration and the shear flows, the current-carrying electrons precipitate into different geometrical patterns, causing circular flares, umbral flares, two-ribbon flares, etc. Thus, it is suggested that ''low temperature flares'' are directly driven by the photospheric dynamo process. (author)

  20. Solar flare impulsivity and its relationship with white-light flares and with CMEs

    Watanabe, K.; Masuda, S.

    2017-12-01

    There are many types of classification in solar flares. One of them is a classification by flare duration in soft X-rays; so-called impulsive flare and long duration event (LDE). Typically, the duration of an impulsive flare is shorter than 1 hour, and that of an LDE is longer than 1 hour. These two types of flare show different characteristics. In soft X-rays, impulsive flares usually have a compact loop structure. On the other hand, LDEs show a large-scale loop, sometimes a large arcade structure. In hard X-rays (HXRs), the difference appears clear, too. The former shows a strong and short-time (10 minutes) emissions and show a large coronal source. These facts suggest that HXR observation becomes one of a good indicator to classify solar flares, especially for the study on the particle acceleration and the related phenomena. However, HXR data do not always exist due to the satellite orbit and the small sensitivity of HXR instruments. So, in this study, based on the concept of the Neupert effect (Neupert, 1968), we use soft X-ray derivative data as the proxy of HXR. From this data, we define impulsivity (IP) for each flare. Then we investigate solar flares using this new index. First we apply IP index to white-light flare (WLF) research. We investigate how WL enhancement depends on IP, then it is found that WLF tend to have large IP values. So the flare impulsivity (IP) is one of the important factors if WL enhancement appears or not in a solar flare. Next we investigate how CME itself and/or its physical parameters depend on IP index. It has been believed that most of CMEs are associated with LDEs, but we found that there is only a weak correlation between the existence of CME and IP index. Finally, we also search for the relationship between WLF and CME as a function of IP and discuss the physical condition of WLF.

  1. SphinX catalogue of small flares and brightenings

    Gryciuk, Magdalena; Sylwester, Janusz; Gburek, Szymon; Siarkowski, Marek; Mrozek, Tomasz; Kepa, Anna

    The Solar Photometer in X-rays (SphinX) was designed to measure soft X-ray solar emission in the energy range between 1 keV and 15 keV. The instrument operated from February until November 2009 aboard CORONAS-Photon satellite, during the phase of extraordinary low minimum of solar activity. Thanks to its very high sensitivity SphinX was able to record large number of tiny flares and brightenings. A catalogue of events observed by SphinX will be presented. Results of statistical analysis of events’ characteristics will be discussed.

  2. X-ray Emission Characteristics of Flares Associated with CMEs ...

    tics of solar flares and their relationship with the dynamics of CMEs have ... lation between X-ray peak intensity of the flares with linear speed as well ... shear angle (θ1, measured at the flare onset), the final shear angle (θ2, measured at the.

  3. Solar flares as harbinger of new physics

    Zioutas, K; Semertzidis, Y.; Papaevangelou, T.; Georgiopoulou, E.; Gardikiotis, A.; Dafni, T.; Tsagri, M.; Semertzidis, Y.; Papaevangelou, T.; Dafni, T.

    2011-01-01

    This work provides additional evidence on the involvement of exotic particles like axions and/or other WISPs, following recent measurements during the quietest Sun and flaring Sun. Thus, SPHINX mission observed a minimum basal soft X-rays emission in the extreme solar minimum in 2009. The same scenario (with ~17 meV axions) fits also the dynamical behaviour of white-light solar flares, like the measured spectral components in the visible and in soft X-rays, and, the timing between them. Solar chameleons remain a viable candidate, since they may preferentially convert to photons in outer space.

  4. Impulsive phase of solar flares: theory

    Mackinnon, A.L.

    1986-01-01

    The paper reviews the theoretical interpretation of impulsive phase phenomena in solar flares. The impulsive phase is defined to be that period of approx. 10 - 100s duration, during which the flare radiative output undergoes its most rapid, dramatic increase and decrease. The interpretation of the various impulsive phase radiation signatures are examined, including the i) hard x-ray emission, ii) radio emission, iii) UV, Hα and white light emissions and iv) gamma-ray emission. The acceleration mechanisms are discussed with respect to candidate acceleration mechanisms, and the synthesis of the theory and observations. (UK)

  5. CCR5 delta32, matrix metalloproteinase-9 and disease activity in multiple sclerosis

    Sellebjerg, Finn; Madsen, Hans O; Jensen, Claus V

    2000-01-01

    Chemokines and matrix metalloproteinases (MMPs) appear to be crucial in leukocyte recruitment to the central nervous system in multiple sclerosis (MS). CCR5 delta32, a truncated allele of the CC chemokine receptor CCR5 gene encoding a non-functional receptor, did not confer protection from MS. CCR5...... delta32 was, however, associated with a lower risk of recurrent clinical disease activity. High CSF levels of MMP-9 activity were also associated with recurrent disease activity. These results directly link intrathecal inflammation to disease activity in patients with MS, suggesting that treatments...... targeting CCR5 or treatment with MMP inhibitors may attenuate disease activity in MS...

  6. Parathyroid mitogenic activity in plasma from patients with familial multiple endocrine neoplasia type 1

    Brandi, M.L.; Aurbach, G.D.; Fitzpatrick, L.A.; Quarto, R.; Spiegel, A.M.; Bliziotes, M.M.; Norton, J.A.; Doppman, J.L.; Marx, S.J.

    1986-01-01

    Hyperplasia of the parathyroid glands is a central feature of familial multiple endocrine neoplasia type 1. We used cultured bovine parathyroid cells to test for mitogenic activity in plasma from patients with this disorder. Normal plasma stimulated [ 3 H]thymidine incorporation, on the average, to the same extent as it was stimulated in a plasma-free control culture. This contrasted with the results of the tests with plasma from patients with familial multiple endocrine neoplasia type 1, in which parathyroid mitogenic activity increased 2400 percent over the control value (P less than 0.001). Plasma from these patients also stimulated the proliferation of bovine parathyroid cells in culture, whereas plasma from normal subjects inhibited it. Parathyroid mitogenic activity in plasma from the patients with familial multiple endocrine neoplasia type 1 was greater than that in plasma from patients with various other disorders, including sporadic primary hyperparathyroidism (with adenoma, hyperplasia, or cancer of the parathyroid), sporadic primary hypergastrinemia, sporadic pituitary tumor, familial hypocalciuric hypercalcemia, and multiple endocrine neoplasia type 2 (P less than 0.05). Parathyroid mitogenic activity in the plasma of patients with familial multiple endocrine neoplasia type 1 persisted for up to four years after total parathyroidectomy. The plasma also had far more mitogenic activity in cultures of parathyroid cells than did optimal concentrations of known growth factors or of any parathyroid secretagogue. This mitogenic activity had an apparent molecular weight of 50,000 to 55,000. We conclude that primary hyperparathyroidism in familial multiple endocrine neoplasia type 1 may have a humoral cause

  7. ASASSN-16ae: A POWERFUL WHITE-LIGHT FLARE ON AN EARLY-L DWARF

    Schmidt, Sarah J. [Leibniz-Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, D-14482, Potsdam (Germany); Shappee, Benjamin J.; Seibert, Mark [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Gagné, Jonathan [Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015 (United States); Stanek, K. Z.; Holoien, Thomas W.-S.; Kochanek, C. S. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Prieto, José L. [Núcleo de Astronomía de la Facultad de Ingenierá, Universidad Diego Portales, Av. Ejército 441, Santiago (Chile); Chomiuk, Laura; Strader, Jay [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Dong, Subo, E-mail: sjschmidt@aip.de [Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Road 5, Hai Dian District, Beijing 100871 (China)

    2016-09-10

    We report the discovery and classification of SDSS J053341.43+001434.1 (SDSS0533), an early-L dwarf first discovered during a powerful Δ V< −11 magnitude flare observed as part of the ASAS-SN survey. Optical and infrared spectroscopy indicate a spectral type of L0 with strong H α emission and a blue NIR spectral slope. Combining the photometric distance, proper motion, and radial velocity of SDSS0533 yields three-dimensional velocities of ( U , V , W ) = (14 ± 13, −35 ± 14, −94 ± 22) km s{sup −1}, indicating that it is most likely part of the thick disk population and probably old. The three detections of SDSS0533 obtained during the flare are consistent with a total V -band flare energy of at least 4.9 × 10{sup 33} erg (corresponding to a total thermal energy of at least E {sub tot} > 3.7 × 10{sup 34} erg), placing it among the strongest detected M dwarf flares. The presence of this powerful flare on an old L0 dwarf may indicate that stellar-type magnetic activity persists down to the end of the main sequence and on older ML transition dwarfs.

  8. A giant radio flare from Cygnus X-3 with associated γ-ray emission: The 2011 radio and γ-ray flare of Cyg X-3

    Corbel, S.; Dubus, G.; Tomsick, J. A.; Szostek, A.

    2012-01-01

    With frequent flaring activity of its relativistic jets, Cygnus X-3 (Cyg X-3) is one of the most active microquasars and is the only Galactic black hole candidate with confirmed high-energy γ-ray emission, thanks to detections by Fermi Large Area Telescope (Fermi/LAT) and AGILE. In 2011, we observed Cyg X-3 in order to transit to a soft X-ray state, which is known to be associated with high-energy γ-ray emission. We present the results of a multiwavelength campaign covering a quenched state, when radio emission from Cyg X-3 is at its weakest and the X-ray spectrum is very soft. A giant (~20 Jy) optically thin radio flare marks the end of the quenched state, accompanied by rising non-thermal hard X-rays. Fermi/LAT observations (E≥ 100 MeV) reveal renewed γ-ray activity associated with this giant radio flare, suggesting a common origin for all non-thermal components. In addition, current observations unambiguously show that the γ-ray emission is not exclusively related to the rare giant radio flares. A three-week period of γ-ray emission is also detected when Cyg X-3 was weakly flaring in radio, right before transition to the radio quenched state. There were no γ-rays observed during the ~1-month long quenched state, when the radio flux is weakest. These results suggest transitions into and out of the ultrasoft X-ray (radio-quenched) state trigger γ-ray emission, implying a connection to the accretion process, and also that the γ-ray activity is related to the level of radio flux (and possibly shock formation), strengthening the connection to the relativistic jets.

  9. Time-resolved UVES observations of a stellar flare on the planet host HD 189733 during primary transit

    Klocová, T.; Czesla, S.; Khalafinejad, S.; Wolter, U.; Schmitt, J. H. M. M.

    2017-11-01

    Context. HD 189733 is an exoplanetary system consisting of a transiting hot Jupiter and an active K2V-type main sequence star. Rich manifestations of a stellar activity, like photometric spots or chromospheric flares were repeatedly observed in this system in optical, UV and X-rays. Aims: We aim to use VLT/UVES high resolution (R = 60 000) echelle spectra to study a stellar flare. Methods: We have performed simultaneous analyses of the temporal evolution in several chromospheric stellar lines, namely, the Ca II H & K lines (3933, 3968 Å), H α (6563 Å), H β (4861 Å), H γ (4341 Å), H δ (4102 Å), H ɛ (3970 Å), the Ca II infrared triplet lines (8498, 8542 and 8662 Å), and He I D3 (5875.6 Å). Observations were carried out with a time resolution of approximately 1 min for a duration of four hours, including a complete planetary transit. Results: We determine the energy released during the flare in all studied chromospheric lines combined to be about 8.7 × 1031 erg, which puts this event at the upper end of flare energies observed on the Sun. Our analysis does not reveal any significant delay of the flare peak observed in the Balmer and Ca II H & K lines, although we find a clear difference in the temporal evolution of these lines. The He I D3 shows additional absorption possibly related to the flare event. Based on the flux released in Ca II H & K lines during the flare, we estimate the soft X-ray flux emission to be 7 × 1030 erg. Conclusions: The observed flare can be ranked as a moderate flare on a K-type star and confirms a rather high activity level of HD 189733 host star. The cores of the studied chromospheric lines demonstrate the same behavior and let us study the flare evolution. We demonstrate that the activity of an exoplanet host star can play an important role in the detection of exoplanet atmospheres, since these are frequently discovered as an additional absorption in the line cores. A possible star-planet interaction responsible for a flare

  10. Hepatobiliary fascioliasis with multiple aneurysms and active bleeding: A case report

    Choi, Soo Young; Kim Jae Woon; Jang, Jae Cheon

    2015-01-01

    A 52-year-old woman visited our institution with upper abdominal pain which had lasted for the past two days. Laboratory tests revealed mild leukocytosis, decreased serum hemoglobin, and peripheral blood eosinophilia. CT scans showed multiple ill-defined, hypodense lesions in the peripheral areas of both hepatic lobes and active bleeding with a subcapsular hematoma in the right hepatic lobe. Angiography also showed active bleeding in the right hepatic lobe with multiple aneurysms, so a transarterial coil embolization was performed to stop the bleeding. The endoscopic retrograde cholangiopancreatography revealed several moving flat flukes in the common bile duct, which were pathologically confirmed as Fasciola hepatica.

  11. Hepatobiliary fascioliasis with multiple aneurysms and active bleeding: A case report

    Choi, Soo Young; Kim Jae Woon; Jang, Jae Cheon [Dept. of Radiology, College of Medicine, Yeungnam University, Daegu (Korea, Republic of)

    2015-04-15

    A 52-year-old woman visited our institution with upper abdominal pain which had lasted for the past two days. Laboratory tests revealed mild leukocytosis, decreased serum hemoglobin, and peripheral blood eosinophilia. CT scans showed multiple ill-defined, hypodense lesions in the peripheral areas of both hepatic lobes and active bleeding with a subcapsular hematoma in the right hepatic lobe. Angiography also showed active bleeding in the right hepatic lobe with multiple aneurysms, so a transarterial coil embolization was performed to stop the bleeding. The endoscopic retrograde cholangiopancreatography revealed several moving flat flukes in the common bile duct, which were pathologically confirmed as Fasciola hepatica.

  12. VLBI OBSERVATION OF MICROQUASAR CYG X-3 DURING AN X-RAY STATE TRANSITION FROM SOFT TO HARD IN THE 2007 MAY-JUNE FLARE

    Kim, Jeong-Sook; Kim, Sang Joon [School of Space Science, Kyunghee University, Seocheon-dong, Giheung-si, Gyeonggi-do 446-701 (Korea, Republic of); Kim, Soon-Wook [Korea Astronomy and Space Science Institute, 776 Daedeokdaero, Yuseong, Daejeon 305-348 (Korea, Republic of); Kurayama, Tomoharu [Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Kagoshima 890-0065 (Japan); Honma, Mareki [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Sasao, Tetsuo, E-mail: evony@kasi.re.kr, E-mail: skim@kasi.re.kr [Yaeyama Star Club, Ookawa, Ishigaki, Okinawa 904-0022 (Japan)

    2013-07-20

    We present a radio observation of microquasar Cyg X-3 during an X-ray state transition from ultrasoft to hard state in the 2007 May-June flare using the VLBI Exploration of Radio Astrometry at 22 GHz. During the transition, a short-lived mini-flare of {approx}< 3 hr was detected prior to the major flare. In such a transition, a jet ejection is believed to occur, but there have been no direct observations to support it. An analysis of Gaussian fits to the observed visibility amplitudes shows a time variation of the source axis, or a structural change, during the mini-flare. Our model fits, together with other multiwavelength observations in the radio, soft, and hard X-rays, and the shock-in-jet models for other flaring activities at GHz wavebands, suggest a high possibility of synchrotron flares during the mini-flare, indicative of a predominant contribution from jet activity. Therefore, the mini-flare with an associated structural change is indicative of a jet ejection event in the state transition from ultrasoft to hard state.

  13. Solar flare hard and soft x ray relationship determined from SMM HXRBS and BCS data

    Toot, G. David

    1989-01-01

    The exact nature of the solar flare process is still somewhat a mystery. A key element to understanding flares if the relationship between the hard x rays emitted by the most energetic portions of the flare and the soft x rays from other areas and times. This relationship was studied by comparing hard x ray light curved from the Hard X-Ray Burst Spectrometer (HXRBS) with the soft x ray light curve and its derivation from the Bent Crystal Spectrometer (BCS) which is part of the X-Ray Polychrometer (XRP), these instruments being on the Solar Maximum Mission spacecraft (SMM). Data sample was taken from flares observed with the above instruments during 1980, the peak of the previous maximum of solar activity. Flares were chosen based on complete coverage of the event by several instruments. The HXRBS data covers the x ray spectrum from about 25 keV to about 440 keV in 15 spectral channels, while the BCS data used covers a region of the Spectrum around 3 angstroms including emission from the Ca XIX ion. Both sets of data were summed over their spectral ranges and plotted against time at a maximum time resolution of around 3 seconds. The most popular theory of flares holds that a beam of electrons produces the hard x rays by bremsstrahlung while the soft x rays are the thermal response to this energy deposition. The question is whether the rate of change of soft x ray emission might reflect the variability of the electron beam and hence the variability of the hard x rays. To address this, we took the time derivative of the soft x ray light curve and compared it to the hard flares, 12 of them showed very closed agreement between the soft x ray derivative and the hard x ray light curve. The other five did not show this behavior but were similar to each other in general soft x ray behavior. Efforts to determine basic differences between the two kinds of flares continue. In addition the behavior of soft x ray temperature of flares was examined.

  14. A magnetic neutral sheet as cause of the flare productivity of a delta sunspot group

    Seehafer, N.

    1985-01-01

    Flare observations in the solar activity complex HR 16862, 16863, 16864 at the end of May 1980 are compared with the structure of force-free magnetic fields calculated from photospheric magnetograph measurements. A series of homologous flares connected with a delta configuration in HR 16864 was possibly caused by a magnetic neutral sheet. The delta configuration consisted of the large preceding spot of HR 16864 and a small satellite of opposite polarity. All magnetic flux from the satellite is connected to the main spot, and at the outer edge of the satellite, away from the main spot, a magnetic neutral sheet is found. This agrees with the observation that all penumbra was situated between parent spot and satellite, which is typical of such delta configurations. It is suggested that the flare productivity of these configurations is generally caused by magnetic neutral sheets at the penumbra-free outer boundary of the satellites. (author)

  15. Fermi-LAT View of Bright Flaring Gamma-Ray Blazars

    Bastieri, D.; Ciprini, S.; Gasparrini, D.

    2011-06-01

    The Fermi LAT provides a continuous and uniform monitoring of the Universe in the gamma-ray band. During the first year many gamma-ray blazar flares, some unidentified transients and emission by the Sun while in a quiet state were promptly detected. This is mainly due to the design of the mission, featuring a detector, the LAT with a wide field of view, and to the operation of the spacecraft itself, that can cover every region of the sky every 3 hours. Nevertheless, the scientific exploitation of this monitoring is more fruitful when early information about transients reaches a broader community. In this respect, the indefatigable activity of flare advocates, who worked on weekly shifts to validate the results and quickly broadcast information about flares and new detections, was the key to most scientific results.

  16. Dependence of absolute magnitudes (energies) of flares on the cluster age containing flare stars

    Parsamyan, Eh.S.

    1976-01-01

    Dependences between Δmsub(u) and msub(u) are given for the Orion, NGC 7000, Pleiades and Praesepe aggregations. Maximum absolute values of flares have been calculated for stars with different luminosities. It has been shown that the values of flares can be limited by a straight line which gives the representation on the distribution of maximum values of amplitudes for the stars with different luminosities in an aggregation. Presented are k and m 0 parameters characterizing the lines fot the Orion, NGC 7000, Pleiades and Praesepe aggregation and their age T dependence. From the dependence between k (angular coefficient of straight lines) and lgT for the aggregation with known T the age of those aggregation involving a great amount of flaring stars can be found. The age of flaring stars in the neighbourhood of the Sun has been determined. The age of UV Ceti has been shown by an order to exceed that of the rest stars

  17. Dynamic radio bursts associated with important flare activity in Hale region 16923 and the problem of the relative locations of type II 'slow drift' bursts and coronal transients

    Mckenna-Lawlor, S.M.P.

    1983-03-01

    Seven type-II radio bursts associated with solar flares in the Hale region 16923 on June 27-29, 1980, are characterized on the basis of data from dynamic radio spectra, white-light observations, radioheliograms, SMM-C/P observations, and Helios I magnetic-field and solar-wind measurements. The data are summarized in tables and graphs and discussed in terms of transient events occurring in the same region. The magnetic shock waves recorded during the period by Helios are described, and channeling effects which may have prevented the detection of type-II burst shocks are examined.

  18. Mining Emerging Patterns for Recognizing Activities of Multiple Users in Pervasive Computing

    Gu, Tao; Wu, Zhanqing; Wang, Liang

    2009-01-01

    Understanding and recognizing human activities from sensor readings is an important task in pervasive computing. Existing work on activity recognition mainly focuses on recognizing activities for a single user in a smart home environment. However, in real life, there are often multiple inhabitants...... activity models, and propose an Emerging Pattern based Multi-user Activity Recognizer (epMAR) to recognize both single-user and multiuser activities. We conduct our empirical studies by collecting real-world activity traces done by two volunteers over a period of two weeks in a smart home environment...... sensor readings in a home environment, and propose a novel pattern mining approach to recognize both single-user and multi-user activities in a unified solution. We exploit Emerging Pattern – a type of knowledge pattern that describes significant changes between classes of data – for constructing our...

  19. Physical activity in subjects with multiple sclerosis with focus on gender differences: a survey.

    Anens, Elisabeth; Emtner, Margareta; Zetterberg, Lena; Hellström, Karin

    2014-03-10

    There is increasing research that examines gender-issues in multiple sclerosis (MS), but little focus has been placed on gender-issues regarding physical activity. The aim of the present study was to describe levels of physical activity, self-efficacy for physical activity, fall-related self-efficacy, social support for physical activity, fatigue levels and the impact of MS on daily life, in addition to investigating gender differences. The sample for this cross-sectional cohort study consisted of 287 (84 men; 29.3%) adults with MS recruited from the Swedish Multiple Sclerosis Registry. A questionnaire was sent to the subjects consisting of the self-administrated measurements: Physical Activity Disability Survey - Revised, Exercise Self-Efficacy Scale, Falls-Efficacy Scale (Swedish version), Social Influences on Physical Activity, Fatigue Severity Scale and Multiple Sclerosis Impact Scale. Response rate was 58.2%. Men were less physically active, had lower self-efficacy for physical activity and lower fall-related self-efficacy than women. This was explained by men being more physically affected by the disease. Men also received less social support for physical activity from family members. The level of fatigue and psychological consequences of the disease were similar between the genders in the total sample, but subgroups of women with moderate MS and relapsing remitting MS experienced more fatigue than men. Men were less physically active, probably a result of being more physically affected by the disease. Men being more physically affected explained most of the gender differences found in this study. However, the number of men in the subgroup analyses was small and more research is needed. A gender perspective should be considered in strategies for promoting physical activity in subjects with MS, e.g. men may need more support to be physically active.

  20. Transport and containment of plasma, particles and energy within flares

    Acton, L. W.; Brown, W. A.; Bruner, M. E. C.; Haisch, B. M.; Strong, K. T.

    1983-01-01

    Results from the analysis of flares observed by the Solar Maximum Mission (SMM) and a recent rocket experiment are discussed. Evidence for primary energy release in the corona through the interaction of magnetic structures, particle and plasma transport into more than a single magnetic structure at the time of a flare and a complex and changing magnetic topology during the course of a flare is found. The rocket data are examined for constraints on flare cooling, within the context of simple loop models. These results form a basis for comments on the limitations of simple loop models for flares.

  1. Flare stars of the Orion Nebula - spectra of an outburst

    Carter, B.D.; O'Mara, B.J.; Ross, J.E.

    1988-01-01

    For the first time, detailed, time-resolved spectra of a flare event of an Orion cluster flare star are presented. These spectra, covering ∼ λλ3600-4600, were obtained by using the Anglo-Australian Telescope with a fibre coupler to simultaneously monitor 23 flare stars in the region of the Orion Nebula. The flare spectra reveal continuous emission which filled in the photospheric Ca I 4226 A absorption, and hydrogen Balmer, Ca II H and K, He I 4026 A and He I 4471 A line emission. Overall, the spectral behaviour indicates similarities to strong outbursts of the classical dMe flare stars. (author)

  2. Second-stage acceleration in solar flares

    Mullan, D.J.

    1976-01-01

    A model proposed by Chevalier and Scott to account for cosmic ray acceleration in an expanding supernova remnant is applied to the case of a shock wave injected into the solar corona by a flare. Certain features of solar cosmic rays can be explained by this model. (orig.) [de

  3. A clarification on endodontic flare-ups.

    Morse, D R; Esposito, J V

    1990-09-01

    In an article on endodontic flare-ups by Robert J. Matusow, our research and publications are discussed. Since we found what we consider to be distortions and misinterpretations of our work, it was decided to clarify the apparent discrepancies found in Matusow's article.

  4. Endodontic cellulitis 'flare-up'. Case report.

    Matusow, R J

    1995-02-01

    Endodontic cellulitis involves facial swelling which can vary from mild to severe and can occur as a primary case or a flare-up following initial treatment of asymptomatic teeth with periapical lesions. The microbial spectrum in primary cases involves a significant mixture of anaerobic and facultative aerobic microbes, chiefly streptococci. In a previous study, cultures from flare-up cases, utilizing the same anaerobic techniques as in primary cases, revealed an absence of obligate anaerobes and an 80 per cent incidence of facultative aerobic streptococci. These cases also revealed a significant time lapse from onset of symptoms to the cellulitis phase. No sex or age factors were noted in the primary or flare-up cases. The purpose of this case report is to restate a traditional theory, namely, the alteration of the oxidation/reduction potential (Eh), as a major factor for endodontic cellulitis flare-ups; to confirm the pathogenic potential of oral facultative streptococci; and that asymptomatic endodontic lesions tend to exist with mixed aerobic/anaerobic microbial flora.

  5. Hybrid simulations of chromospheric HXR flare sources

    Moravec, Z.; Varady, Michal; Kašparová, Jana; Kramoliš, D.

    2016-01-01

    Roč. 337, č. 10 (2016), s. 1020-1023 ISSN 0004-6337. [Dynamic Sun - Exploring the Many Facets of Solar Eruptive Events. Potsdam, 26.10.2015-29.10.2015] Institutional support: RVO:67985815 Keywords : Sun * chromosphere * flares Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.916, year: 2016

  6. 40 CFR 65.147 - Flares.

    2010-07-01

    ..., equal to or less than 122 meters per second (400 feet per second) if the net heating value of the gas... section, less than the velocity, V max, and less than 122 meters per second (400 feet per sec), where the... standard cubic meter (300 British thermal units per standard cubic foot) or greater if the flare is steam...

  7. Suitability of public use secondary data sets to study multiple activities.

    Putnam, Michelle; Morrow-Howell, Nancy; Inoue, Megumi; Greenfield, Jennifer C; Chen, Huajuan; Lee, YungSoo

    2014-10-01

    The aims of this study were to inventory activity items within and across U.S. public use data sets, to identify gaps in represented activity domains and challenges in interpreting domains, and to assess the potential for studying multiple activity engagement among older adults using existing data. We engaged in content analysis of activity measures of 5U.S. public use data sets with nationally representative samples of older adults. Data sets included the Health & Retirement Survey (HRS), Americans' Changing Lives Survey (ACL), Midlife in the United States Survey (MIDUS), the National Health Interview Survey (NHIS), and the Panel Study of Income Dynamics survey (PSID). Two waves of each data set were analyzed. We identified 13 distinct activity domains across the 5 data sets, with substantial differences in representation of those domains among the data sets, and variance in the number and type of activity measures included in each. Our findings indicate that although it is possible to study multiple activity engagement within existing data sets, fuller sets of activity measures need to be developed in order to evaluate the portfolio of activities older adults engage in and the relationship of these portfolios to health and wellness outcomes. Importantly, clearer conceptual models of activity broadly conceived are required to guide this work. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. TEMPORAL AND SPATIAL RELATIONSHIP OF FLARE SIGNATURES AND THE FORCE-FREE CORONAL MAGNETIC FIELD

    Thalmann, J. K.; Veronig, A.; Su, Y., E-mail: julia.thalmann@uni-graz.at [Institute of Physics/IGAM, University of Graz, Universitätsplatz 5/II, A-8010 Graz (Austria)

    2016-08-01

    We investigate the plasma and magnetic environment of active region NOAA 11261 on 2011 August 2 around a GOES M1.4 flare/CME (SOL2011-08-02T06:19). We compare coronal emission at the (extreme) ultraviolet and X-ray wavelengths, using SDO AIA and RHESSI images, in order to identify the relative timing and locations of reconnection-related sources. We trace flare ribbon signatures at ultraviolet wavelengths in order to pin down the intersection of previously reconnected flaring loops in the lower solar atmosphere. These locations are used to calculate field lines from three-dimensional (3D) nonlinear force-free magnetic field models, established on the basis of SDO HMI photospheric vector magnetic field maps. Using this procedure, we analyze the quasi-static time evolution of the coronal model magnetic field previously involved in magnetic reconnection. This allows us, for the first time, to estimate the elevation speed of the current sheet’s lower tip during an on-disk observed flare as a few kilometers per second. A comparison to post-flare loops observed later above the limb in STEREO EUVI images supports this velocity estimate. Furthermore, we provide evidence for an implosion of parts of the flaring coronal model magnetic field, and identify the corresponding coronal sub-volumes associated with the loss of magnetic energy. Finally, we spatially relate the build up of magnetic energy in the 3D models to highly sheared fields, established due to the dynamic relative motions of polarity patches within the active region.

  9. A SOLAR FLARE DISTURBING A LIGHT WALL ABOVE A SUNSPOT LIGHT BRIDGE

    Hou, Yijun; Zhang, Jun; Li, Ting; Yang, Shuhong; Li, Leping; Li, Xiaohong, E-mail: yijunhou@nao.cas.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2016-10-01

    With the high-resolution data from the Interface Region Imaging Spectrograph , we detect a light wall above a sunspot light bridge in the NOAA active region (AR) 12403. In the 1330 Å slit-jaw images, the light wall is brighter than the ambient areas while the wall top and base are much brighter than the wall body, and it keeps oscillating above the light bridge. A C8.0 flare caused by a filament activation occurred in this AR with the peak at 02:52 UT on 2015 August 28, and the flare’s one ribbon overlapped the light bridge, which was the observational base of the light wall. Consequently, the oscillation of the light wall was evidently disturbed. The mean projective oscillation amplitude of the light wall increased from 0.5 to 1.6 Mm before the flare and decreased to 0.6 Mm after the flare. We suggest that the light wall shares a group of magnetic field lines with the flare loops, which undergo a magnetic reconnection process, and they constitute a coupled system. When the magnetic field lines are pushed upward at the pre-flare stage, the light wall turns to the vertical direction, resulting in the increase of the light wall’s projective oscillation amplitude. After the magnetic reconnection takes place, a group of new field lines with smaller scales are formed underneath the reconnection site, and the light wall inclines. Thus, the projective amplitude notably decrease at the post-flare stage.

  10. A SOLAR FLARE DISTURBING A LIGHT WALL ABOVE A SUNSPOT LIGHT BRIDGE

    Hou, Yijun; Zhang, Jun; Li, Ting; Yang, Shuhong; Li, Leping; Li, Xiaohong

    2016-01-01

    With the high-resolution data from the Interface Region Imaging Spectrograph , we detect a light wall above a sunspot light bridge in the NOAA active region (AR) 12403. In the 1330 Å slit-jaw images, the light wall is brighter than the ambient areas while the wall top and base are much brighter than the wall body, and it keeps oscillating above the light bridge. A C8.0 flare caused by a filament activation occurred in this AR with the peak at 02:52 UT on 2015 August 28, and the flare’s one ribbon overlapped the light bridge, which was the observational base of the light wall. Consequently, the oscillation of the light wall was evidently disturbed. The mean projective oscillation amplitude of the light wall increased from 0.5 to 1.6 Mm before the flare and decreased to 0.6 Mm after the flare. We suggest that the light wall shares a group of magnetic field lines with the flare loops, which undergo a magnetic reconnection process, and they constitute a coupled system. When the magnetic field lines are pushed upward at the pre-flare stage, the light wall turns to the vertical direction, resulting in the increase of the light wall’s projective oscillation amplitude. After the magnetic reconnection takes place, a group of new field lines with smaller scales are formed underneath the reconnection site, and the light wall inclines. Thus, the projective amplitude notably decrease at the post-flare stage.

  11. Effects of Multiple Intelligences Activities on Writing Skill Development in an EFL Context

    Gündüz, Zennure Elgün; Ünal, Ismail Dogan

    2016-01-01

    This study aims at exploring the effects of multiple intelligences activities versus traditional method on English writing development of the sixth grade students in Turkey. A quasi-experimental research method with a pre-test post-test design was applied. The participants were 50 sixth grade students at a state school in Ardahan in Turkey. The…

  12. Fingolimod in active multiple sclerosis: an impressive decrease in Gd-enhancing lesions

    Muris, A.H.; Rolf, L.; Damoiseaux, J.; Koeman, E.; Hupperts, R.

    2014-01-01

    Background: Fingolimod is a disease modifying therapy (DMT) in highly active relapsing remitting multiple sclerosis (RRMS), as is natalizumab. Fingolimod decreases annual relapse rates and gadolinium enhancing lesions on MRI as compared to either interferon beta (IFNβ) or placebo. The effect of

  13. Field Measurements of Black Carbon Yields from Gas Flaring.

    Conrad, Bradley M; Johnson, Matthew R

    2017-02-07

    Black carbon (BC) emissions from gas flaring in the oil and gas industry are postulated to have critical impacts on climate and public health, but actual emission rates remain poorly characterized. This paper presents in situ field measurements of BC emission rates and flare gas volume-specific BC yields for a diverse range of flares. Measurements were performed during a series of field campaigns in Mexico and Ecuador using the sky-LOSA optical measurement technique, in concert with comprehensive Monte Carlo-based uncertainty analyses. Parallel on-site measurements of flare gas flow rate and composition were successfully performed at a subset of locations enabling direct measurements of fuel-specific BC yields from flares under field conditions. Quantified BC emission rates from individual flares spanned more than 4 orders of magnitude (up to 53.7 g/s). In addition, emissions during one notable ∼24-h flaring event (during which the plume transmissivity dropped to zero) would have been even larger than this maximum rate, which was measured as this event was ending. This highlights the likely importance of superemitters to global emission inventories. Flare gas volume-specific BC yields were shown to be strongly correlated with flare gas heating value. A newly derived correlation fitting current field data and previous lab data suggests that, in the context of recent studies investigating transport of flare-generated BC in the Arctic and globally, impacts of flaring in the energy industry may in fact be underestimated.

  14. Study on the flare stars in the Taurus region

    Khodzhaev, A.S.

    1986-01-01

    The results of the search of flare stars and their photometric, Hsub(α)-spectroscopic and statistical study in the Taurus are presented. By means of photographic observations carried out during 1980-1984, 92 new flare stars were discovered, 13 of which are known Orion Population variables, and 16 repeated flare-ups among 13 known flare stars. Spatial distribution of these stars was considered and the problem of their membership was discussed. Comparative analysis of the data of flare stars in the Taurus with that of other systems has been carried out. The Herzsprung-Russel and two-colour (U-B, B-V) diagrams for the Taurus flare stars are similar to the diagrams of stellar clusters and associations (Pleiades, Orion etc.). The estimated total number of flare stars in this region is larger than 500

  15. Management of routine solution gas flaring in Alberta

    1998-01-01

    Alberta's Clean Air Strategic Alliance (CASA) shares decision-making responsibilities with the Government of Alberta for strategic aspects of air quality. In 1997, the Alliance established the Flaring Project Team to develop recommendations that address potential and observed impacts associated with flaring, with particular focus on 'upstream solution gas' flaring. The upstream industry explores for, acquires, develops, produces and markets crude oil and natural gas. Essentially, solution gas at upstream sites is 'co-produced' during crude oil production. The project team was established to collect and summarize information on flaring and its impacts and to develop recommendations for short-term actions to minimize the practice of routine flaring of solution gas. Another goal of the team is to develop a research strategy to better understand flaring emissions and their effects on human, animal and environmental health. The team is working on developing long-term strategies for actions to address the gas flaring issue. 5 refs., 1 tab., 7 figs

  16. Dynamic data-driven integrated flare model based on self-organized criticality

    Dimitropoulou, M.; Isliker, H.; Vlahos, L.; Georgoulis, M. K.

    2013-05-01

    Context. We interpret solar flares as events originating in active regions that have reached the self-organized critical state. We describe them with a dynamic integrated flare model whose initial conditions and driving mechanism are derived from observations. Aims: We investigate whether well-known scaling laws observed in the distribution functions of characteristic flare parameters are reproduced after the self-organized critical state has been reached. Methods: To investigate whether the distribution functions of total energy, peak energy, and event duration follow the expected scaling laws, we first applied the previously reported static cellular automaton model to a time series of seven solar vector magnetograms of the NOAA active region 8210 recorded by the Imaging Vector Magnetograph on May 1 1998 between 18:59 UT and 23:16 UT until the self-organized critical state was reached. We then evolved the magnetic field between these processed snapshots through spline interpolation, mimicking a natural driver in our dynamic model. We identified magnetic discontinuities that exceeded a threshold in the Laplacian of the magnetic field after each interpolation step. These discontinuities were relaxed in local diffusion events, implemented in the form of cellular automaton evolution rules. Subsequent interpolation and relaxation steps covered all transitions until the end of the processed magnetograms' sequence. We additionally advanced each magnetic configuration that has reached the self-organized critical state (SOC configuration) by the static model until 50 more flares were triggered, applied the dynamic model again to the new sequence, and repeated the same process sufficiently often to generate adequate statistics. Physical requirements, such as the divergence-free condition for the magnetic field, were approximately imposed. Results: We obtain robust power laws in the distribution functions of the modeled flaring events with scaling indices that agree well

  17. Microbial causes of endodontic flare-ups.

    Siqueira, Jose F

    2003-07-01

    Inter-appointment flare-up is characterized by the development of pain, swelling or both, following endodontic intervention. The causative factors of flare-ups encompass mechanical, chemical and/or microbial injury to the pulp or periradicular tissues. Of these factors, microorganisms are arguably the major causative agents of flare-ups. Even though the host is usually unable to eliminate the root canal infection, mobilization and further concentration of defence components at the periradicular tissues impede spreading of infection, and a balance between microbial aggression and host defences is commonly achieved. There are some situations during endodontic therapy in which such a balance may be disrupted in favour of microbial aggression, and an acute periradicular inflammation can ensue. Situations include apical extrusion of infected debris, changes in the root canal microbiota and/or in environmental conditions caused by incomplete chemo-mechanical preparation, secondary intraradicular infections and perhaps the increase in the oxidation-reduction potential within the root canal favouring the overgrowth of the facultative bacteria. Based on these situations, preventive measures against infective flare-ups are proposed, including selection of instrumentation techniques that extrude lesser amounts of debris apically; completion of the chemo-mechanical procedures in a single visit; use of an antimicrobial intracanal medicament between appointments in the treatment of infected cases; not leaving teeth open for drainage and maintenance of the aseptic chain throughout endodontic treatment. Knowledge about the microbial causes of flare-ups and adoption of appropriate preventive measures can significantly reduce the incidence of this highly distressing and undesirable clinical phenomenon.

  18. Exploring the facilitators and barriers to engagement in physical activity for people with multiple sclerosis.

    Kayes, Nicola M; McPherson, Kathryn M; Schluter, Philip; Taylor, Denise; Leete, Marta; Kolt, Gregory S

    2011-01-01

    To explore the relationship that cognitive behavioural and other previously identified variables have with physical activity engagement in people with multiple sclerosis (MS). This study adopted a cross-sectional questionnaire design. Participants were 282 individuals with MS. Outcome measures included the Physical Activity Disability Survey--Revised, Cognitive and Behavioural Responses to Symptoms Questionnaire, Barriers to Health Promoting Activities for Disabled Persons Scale, Multiple Sclerosis Self-efficacy Scale, Self-Efficacy for Chronic Diseases Scales and Chalder Fatigue Questionnaire. Multivariable stepwise regression analyses found that greater self-efficacy, greater reported mental fatigue and lower number of perceived barriers to physical activity accounted for a significant proportion of variance in physical activity behaviour, over that accounted for by illness-related variables. Although fear-avoidance beliefs accounted for a significant proportion of variance in the initial analyses, its effect was explained by other factors in the final multivariable analyses. Self-efficacy, mental fatigue and perceived barriers to physical activity are potentially modifiable variables which could be incorporated into interventions designed to improve physical activity engagement. Future research should explore whether a measurement tool tailored to capture beliefs about physical activity identified by people with MS would better predict participation in physical activity.

  19. Automatic detection of white-light flare kernels in SDO/HMI intensitygrams

    Mravcová, L.; Švanda, Michal

    2017-01-01

    Roč. 57, November (2017), s. 14-21 ISSN 1384-1076 Institutional support: RVO:67985815 Keywords : Sun * activity * flares Subject RIV: BN - Astronomy , Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 0.938, year: 2016

  20. A Very Small and Super Strong Zebra Pattern Burst at the Beginning of a Solar Flare

    Tan, B.-L.; Tan, C.M.; Zhang, Y.; Huang, J.; Mészárosová, Hana; Karlický, Marian; Yan, Y.

    2014-01-01

    Roč. 790, č. 2 (2014), 151/1-151/6 ISSN 0004-637X R&D Projects: GA ČR GAP209/12/0103 Institutional support: RVO:67985815 Keywords : Sun: activity * Sun: flares * Sun: particle emission Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.993, year: 2014

  1. A comparison between r-LH and urinary supplements containing LH activity in patients undergoing the microdose GnRH agonist flare protocol for in-vitro fertilization: a pilot study.

    Shavit, Tal; Agdi, Mohammed; Son, Weon Y; Hasson, Josseph; Dahan, Michael H

    2016-08-01

    The aim of this study was to compare pregnancy rates and stimulation parameters in patients with diminished ovarian reserve, who were treated with recombinant human luteinizing hormone (r-LH) or menopausal gonadotropins (hMG), as part of a microdose flare protocol. A retrospective cohort study was performed. Comparisons between the group that was stimulated with r-LH plus follicle stimulating hormone (FSH) to those treated with hMG and FSH, were performed. Measurements included: medication doses, number of oocyte collected, number of embryos obtained, pregnancy and clinical pregnancy rates. Patients in the r-LH group (N.=40) had significant higher clinical pregnancy rates (33% vs. 14%; P=0.04) and used lower dose of LH (1938 IU vs. 2807 IU; P=0.02) compared to patients that were stimulated with hMG (N.=39). r-LH may offer advantages for the treatment of diminished ovarian reserve when performing a microdose flare protocol when compared to hMG. Both larger and prospective studies should be carried out to confirm these findings.

  2. The regulatory context of gas flaring in Alberta

    Gilmour, B.S.; Cook, C.

    1999-01-01

    The legislative and regulatory regime regarding gas flaring in Alberta was reviewed. The issue of gas flaring has received much attention from petroleum industry regulators in Alberta. Residents living in the vicinity of flares have identified them as sources of odour, smoke, noise and air quality-related health concerns. Sulfur dioxide and carbon dioxide emissions from the flare stacks may contribute to acid rain and the greenhouse effect. The Strosher Report, released by the Alberta Research Council in 1996, has also identified about 250 different compounds in flare emissions, including volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and other products of incomplete combustion. The public opposition to solution gas flaring has caused regulators to consider new options designed to reduce the adverse economic and environmental impacts that may be associated with gas flaring. This paper discusses the roles of the Alberta Energy and Utilities Board (EUB) and Alberta Environmental Protection in administering legislation that impacts on gas flaring. In March 1999, the EUB released a guide containing the following five major points regarding gas flaring: (1) implementation of the Clean Air Strategic Alliance's (CASA's) recommendations to eventually eliminate flaring, by starting immediately to reduce flaring, and improve the efficiency of flares, (2) adoption of the CASA schedule of reduction targets for solution gas flaring, (3) conducting a review of the current approval process for small-scale electrical generation systems to encourage co-generation as a productive use of solution gas that is being flared, (4) creating better public notification requirements for new and existing facilities, and (5) discussing conflict resolution between operators and landowners. 26 refs

  3. Progress report on recommendations of the Flaring Project Team

    Macken, C.

    1999-01-01

    Part of the mandate of the Clean Air Strategic Alliance (CASA) is to share decision-making responsibility for air quality management with the government of Alberta, through the ministries of Environmental Protection, Energy, and Health, and the Alberta Energy and Utilities Board (EUB). CASA's vision for air quality in Alberta is that 'the air will be odourless, tasteless, look clear, and have no measurable short- or long-term adverse effects on people, animals, or the environment'. In 1997, CASA approved the establishment of the Flaring Project Team in response to public concern about potential and observed impacts associated with flaring of solution gas. Members of that team established a framework for the management of solution gas flaring. Their long-term goal is to eliminate routine flaring of solution gas. The Project Team assessed existing information on solution gas flaring, including technologies, efficiencies, emissions and impacts. Alternative technologies were also reviewed along with biological and health effects of solution gas flaring. A list of data gaps and research needs was compiled in order to help with the development of the Team's recommendations. The Team's final report was delivered in June 1998. It was recommended that the following policy objective hierarchy be used to guide decisions related to routine solution gas flaring: (1) eliminate routine solution gas flaring, (2) reduce volumes of gas flared, and (3) improve the efficiency of flares. By way of progress the Project Team was able to report that in March, 1999, the EUB issued a draft interim directive to address upstream petroleum industry flaring. The draft Directive incorporates the recommendations from the CASA Flaring Project Team with respect to management of solution gas flaring. In December 1998, changes to the royalty structure to encourage the productive use of flare gas have been announced by the Alberta Department of Energy and Alberta Environmental protection, thus

  4. Dynamic activity of NF-κB in multiple trauma patients and protective effects of ulinastain

    LI Jun

    2012-02-01

    Full Text Available 【Abstract】Objective: To investigate the dynamic activity of NF-κB at the early stage of injury in multiple trauma patients and the protective effects of ulinastain. Methods: From January 2008 to May 2010, patients with multiple traumas admitted to our emergency department were enrolled in this study. Their age varied from 20-55 years. All enrolled patients were assigned randomly into control group (26 cases of multiple injury without ulinastain treatment, ulinastain group (25 cases of multiple injury with ulinastain treatment, and mild injury group (20 cases for basic control. The inclusion criteria for mild injury group were AIS-2005≤3, single wound, previously healthy inhospital patients without the history of surgical intervention. In addition to routine treatment, patients in ulinastain group were intravenously injected 200 000 IU of ulinastain dissolved in 100 ml of normal saline within 12 hours after injury and subsequently injected at the interval of every 8 hours for 7 days. NF-κB activity in monocytes and the level of TNF? IL-1, IL? in serum on admission (day 0, day 1, 2, 3, 4, and 7 were measured. Data were compared and analyzed between different groups. Results: NF-κB activity in monocytes and TNF? IL-1 and IL? of these patients reached peak levels at 24 hour after trauma, with gradual decrease to normal at 72 hour after trauma. NF-κB activity and levels of TNF? IL-1 and IL? were lower in ulinastain group than control one, without any significant difference between the two groups. The mean duration for systemic inflammatory response syndrome and multiple organ dysfunction syndrome was 7 d?.1 d and 10 d?.5 d in ulinastain group and control group respectively, and showed a significant difference. Conclusions: NF-κB activity in monocytes and the levels of inflammatory cytokines in multiply injured patients increased transiently at the early stage of trauma. Ulinastain may shorten the duration of systemic inflammatory

  5. T helper 17.1 cells associate with multiple sclerosis disease activity: perspectives for early intervention.

    van Langelaar, Jamie; van der Vuurst de Vries, Roos M; Janssen, Malou; Wierenga-Wolf, Annet F; Spilt, Isis M; Siepman, Theodora A; Dankers, Wendy; Verjans, Georges M G M; de Vries, Helga E; Lubberts, Erik; Hintzen, Rogier Q; van Luijn, Marvin M

    2018-05-01

    Interleukin-17-expressing CD4+ T helper 17 (Th17) cells are considered as critical regulators of multiple sclerosis disease activity. However, depending on the species and pro-inflammatory milieu, Th17 cells are functionally heterogeneous, consisting of subpopulations that differentially produce interleukin-17, interferon-gamma and granulocyte macrophage colony-stimulating factor. In the current study, we studied distinct effector phenotypes of human Th17 cells and their correlation with disease activity in multiple sclerosis patients. T helper memory populations single- and double-positive for C-C chemokine receptor 6 (CCR6) and CXC chemokine receptor 3 (CXCR3) were functionally assessed in blood and/or cerebrospinal fluid from a total of 59 patients with clinically isolated syndrome, 35 untreated patients and 24 natalizumab-treated patients with relapsing-remitting multiple sclerosis, and nine patients with end-stage multiple sclerosis. Within the clinically isolated syndrome group, 23 patients had a second attack within 1 year and 26 patients did not experience subsequent attacks during a follow-up of >5 years. Low frequencies of T helper 1 (Th1)-like Th17 (CCR6+CXCR3+), and not Th17 (CCR6+CXCR3-) effector memory populations in blood strongly associated with a rapid diagnosis of clinically definite multiple sclerosis. In cerebrospinal fluid of clinically isolated syndrome and relapsing-remitting multiple sclerosis patients, Th1-like Th17 effector memory cells were abundant and showed increased production of interferon-gamma and granulocyte macrophage colony-stimulating factor compared to paired CCR6+ and CCR6-CD8+ T cell populations and their blood equivalents after short-term culturing. Their local enrichment was confirmed ex vivo using cerebrospinal fluid and brain single-cell suspensions. Across all pro-inflammatory T helper cells analysed in relapsing-remitting multiple sclerosis blood, Th1-like Th17 subpopulation T helper 17.1 (Th17.1; CCR6+CXCR3+CCR4

  6. ULTRAVIOLET AND EXTREME-ULTRAVIOLET EMISSIONS AT THE FLARE FOOTPOINTS OBSERVED BY ATMOSPHERE IMAGING ASSEMBLY

    Qiu Jiong; Longcope, Dana W.; Liu Wenjuan [Department of Physics, Montana State University, Bozeman, MT 59717-3840 (United States); Sturrock, Zoe [Department of Applied Mathematics, University of St. Andrews (United Kingdom); Klimchuk, James A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-09-01

    A solar flare is composed of impulsive energy release events by magnetic reconnection, which forms and heats flare loops. Recent studies have revealed a two-phase evolution pattern of UV 1600 A emission at the feet of these loops: a rapid pulse lasting for a few seconds to a few minutes, followed by a gradual decay on timescales of a few tens of minutes. Multiple band EUV observations by the Atmosphere Imaging Assembly further reveal very similar signatures. These two phases represent different but related signatures of an impulsive energy release in the corona. The rapid pulse is an immediate response of the lower atmosphere to an intense thermal conduction flux resulting from the sudden heating of the corona to high temperatures (we rule out energetic particles due to a lack of significant hard X-ray emission). The gradual phase is associated with the cooling of hot plasma that has been evaporated into the corona. The observed footpoint emission is again powered by thermal conduction (and enthalpy), but now during a period when approximate steady-state conditions are established in the loop. UV and EUV light curves of individual pixels may therefore be separated into contributions from two distinct physical mechanisms to shed light on the nature of energy transport in a flare. We demonstrate this technique using coordinated, spatially resolved observations of UV and EUV emissions from the footpoints of a C3.2 thermal flare.

  7. Semi-active control of a cable-stayed bridge under multiple-support excitations.

    Dai, Ze-Bing; Huang, Jin-Zhi; Wang, Hong-Xia

    2004-03-01

    This paper presents a semi-active strategy for seismic protection of a benchmark cable-stayed bridge with consideration of multiple-support excitations. In this control strategy, Magnetorheological (MR) dampers are proposed as control devices, a LQG-clipped-optimal control algorithm is employed. An active control strategy, shown in previous researches to perform well at controlling the benchmark bridge when uniform earthquake motion was assumed, is also used in this study to control this benchmark bridge with consideration of multiple-support excitations. The performance of active control system is compared to that of the presented semi-active control strategy. Because the MR fluid damper is a controllable energy- dissipation device that cannot add mechanical energy to the structural system, the proposed control strategy is fail-safe in that bounded-input, bounded-output stability of the controlled structure is guaranteed. The numerical results demonstrated that the performance of the presented control design is nearly the same as that of the active control system; and that the MR dampers can effectively be used to control seismically excited cable-stayed bridges with multiple-support excitations.

  8. Activation of multiple chemotherapeutic prodrugs by the natural enzymolome of tumour-localised probiotic bacteria.

    Lehouritis, Panos; Stanton, Michael; McCarthy, Florence O; Jeavons, Matthieu; Tangney, Mark

    2016-01-28

    Some chemotherapeutic drugs (prodrugs) require activation by an enzyme for efficacy. We and others have demonstrated the ability of probiotic bacteria to grow specifically within solid tumours following systemic administration, and we hypothesised that the natural enzymatic activity of these tumour-localised bacteria may be suitable for activation of certain such chemotherapeutic drugs. Several wild-type probiotic bacteria; Escherichia coli Nissle, Bifidobacterium breve, Lactococcus lactis and Lactobacillus species, were screened against a panel of popular prodrugs. All strains were capable of activating at least one prodrug. E. coli Nissle 1917 was selected for further studies because of its ability to activate numerous prodrugs and its resistance to prodrug toxicity. HPLC data confirmed biochemical transformation of prodrugs to their toxic counterparts. Further analysis demonstrated that different enzymes can complement prodrug activation, while simultaneous activation of multiple prodrugs (CB1954, 5-FC, AQ4N and Fludarabine phosphate) by E. coli was confirmed, resulting in significant efficacy improvement. Experiments in mice harbouring murine tumours validated in vitro findings, with significant reduction in tumour growth and increase in survival of mice treated with probiotic bacteria and a combination of prodrugs. These findings demonstrate the ability of probiotic bacteria, without the requirement for genetic modification, to enable high-level activation of multiple prodrugs specifically at the site of action. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. He I D3 OBSERVATIONS OF THE 1984 MAY 22 M6.3 SOLAR FLARE

    Liu Chang; Xu Yan; Deng Na; Lee, Jeongwoo; Zhang Jifeng; Wang Haimin [Space Weather Research Laboratory, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States); Prasad Choudhary, Debi, E-mail: chang.liu@njit.edu [Physics and Astronomy Department, California State University Northridge, 18111 Nordhoff Street, Northridge, CA 91330-0001 (United States)

    2013-09-01

    The He I D3 line has a unique response to a flare impact on the low solar atmosphere and can be a powerful diagnostic tool for energy transport processes. Using images obtained from the recently digitized films of the Big Bear Solar Observatory, we report D3 observations of the M6.3 flare on 1984 May 22, which occurred in an active region with a circular magnetic polarity inversion line (PIL). The impulsive phase of the flare starts with a main elongated source that darkens in D3, inside of which bright emission kernels appear at the time of the initial small peak in hard X-rays (HXRs). These flare cores subsequently evolve into a sharp emission strand lying within the dark halo; this evolution occurs at the same time as the main peak in HXRs, reversing the overall source contrast from -5% to 5%. The radiated energy in D3 during the main peak is estimated to be about 10{sup 30} erg, which is comparable to that carried by nonthermal electrons above 20 keV. Afterward, the flare proceeds along the circular PIL in the counterclockwise direction to form a dark circular ribbon in D3, which apparently mirrors the bright ribbons in H{alpha} and He I 10830 A. All of these ribbons last for over one hour in the late gradual phase. We suggest that the present event resembles the so-called black-light flare that was proposed based on continuum images, and that D3 darkening and brightening features herein may be due to thermal conduction heating and the direct precipitation of high-energy electrons, respectively.

  10. Hamster activity and estrous cycles: control by a single versus multiple circadian oscillator(s).

    Carmichael, M S; Nelson, R J; Zucker, I

    1981-01-01

    Running activity onset and estrous onset were recorded for hamsters exposed to progressively shorter daily light/dark (T) cycles. The period of the estrous cycle was a quadruple multiple of the period of the activity rhythm during entrainment to T cycles of 23.5-21.5 hr. There was no evidence of desynchronization of the activity and estrus rhythms. The very short estrous periods shown during exposure to short T cycles indicate that an intrinsic 96-hr interval for ovarian follicular maturation...

  11. Pots and Pans Activities for Parent and Child: Activities for Preschool Multiple Handicapped Children.

    Van Tassel, Jean

    Intended for parents and teachers of multiply handicapped preschool children, the booklet provides lesson plans in three major areas--basic concepts, motor activities, and language activities. Each lesson plan is broken down into four parts: purpose (a descriptive statement of what the lesson hopes to accomplish), materials (list of materials…

  12. Reserve-building activities in multiple sclerosis patients and healthy controls: a descriptive study.

    Schwartz, Carolyn E; Ayandeh, Armon; Ramanathan, Murali; Benedict, Ralph; Dwyer, Michael G; Weinstock-Guttman, Bianca; Zivadinov, Robert

    2015-08-12

    Cognitive reserve has been implicated as a possible protective factor in multiple sclerosis (MS) but to date no study has compared reserve-building activities across disease course or to healthy controls. This study aims to describe differences in reserve-building activities across the MS disease course and healthy controls. Secondary analysis of a cross-sectional cohort study that included 276 healthy controls, and subjects with clinically isolated syndrome (CIS; n = 67), relapsing-remitting MS (RRMS; n = 358) and secondary progressive MS (PMS; n = 109). Past reserve-building activities were operationalized as occupational attainment and education. Current activities comprised 6 strenuous and 6 non-strenuous activities, including 5 reserve-building activities and television-watching. Multivariate Analysis of Variance models examined group differences in past and current activities, after adjusting for covariates. There were group differences in past and current reserve-building activities. SPMS patients had lower past reserve-building activities than healthy controls. All forms of MS engaged in fewer strenuous current reserve-building pursuits than healthy controls. RRMS read less than healthy controls. SPMS engaged in fewer job-related non-strenuous activities. All MS groups watched more television than healthy controls. MS patients show significantly fewer past and present reserve-building activities. Although it is difficult to establish causality without future prospective studies, lifestyle-modifying interventions should prioritize expanding MS patients' repertoire of strenuous and non-strenuous activities.

  13. The relationship between walking, manual dexterity, cognition and activity/participation in persons with multiple sclerosis.

    Kierkegaard, Marie; Einarsson, Ulrika; Gottberg, Kristina; von Koch, Lena; Holmqvist, Lotta Widén

    2012-05-01

    Multiple sclerosis has a vast impact on health, but the relationship between walking, manual dexterity, cognition and activity/participation is unclear. The specific aims were to explore the discriminative ability of measures of walking, manual dexterity and cognition, and to identify cut-off values in these measures, for prediction of independence in personal and instrumental activities of daily living (ADL) and activity/participation in social and lifestyle activities. Data from 164 persons with multiple sclerosis were collected during home visits with the following measures: the 2 × 5 m walk test, the Nine-hole Peg Test, the Symbol Digit Modalities Test, the Katz Personal and Instrumental ADL Indexes, and the Frenchay Activities Index (measuring frequency in social and lifestyle activities). The 2 × 5 m walk test and the Nine-hole Peg Test had high and better discriminative and predictive ability than the Symbol Digit Modalities Test. Cut-off values were identified. The accuracy of predictions was increased above all by combining the 2 × 5 m walk test and the Nine-hole Peg Test. The proposed cut-off values in the 2 × 5 m walk test and the Nine-hole Peg Test may be used as indicators of functioning and to identify persons risking activity limitations and participation restrictions. However, further studies are needed to confirm the usefulness in clinical practice.

  14. Multiple-clone activation of hypnozoites is the leading cause of relapse in Plasmodium vivax infection.

    Flávia Carolina F de Araujo

    Full Text Available BACKGROUND: Plasmodium vivax infection is characterized by a dormant hepatic stage, the hypnozoite that is activated at varying periods of time after clearance of the primary acute blood-stage, resulting in relapse. Differentiation between treatment failure and new infections requires characterization of initial infections, relapses, and clone multiplicity in vivax malaria infections. METHODOLOGY/PRINCIPAL FINDINGS: Parasite DNA obtained from primary/relapse paired blood samples of 30 patients with P. vivax infection in Brazil was analyzed using 10 molecular markers (8 microsatellites and MSP-1 blocks 2 and 10. Cloning of PCR products and genotyping was used to identify low-frequency clones of parasites. We demonstrated a high frequency of multiple-clone infections in both primary and relapse infections. Few alleles were identified per locus, but the combination of these alleles produced many haplotypes. Consequently, the majority of parasites involved in relapse showed haplotypes that were distinct from those of primary infections. Plasmodium vivax relapse was characterized by temporal variations in the predominant parasite clones. CONCLUSIONS/SIGNIFICANCE: The high rate of low frequency alleles observed in both primary and relapse infections, along with temporal variation in the predominant alleles, might be the source of reported heterologous hypnozoite activation. Our findings complicate the concept of heterologous activation, suggesting the involvement of undetermined mechanisms based on host or environmental factors in the simultaneous activation of multiple clones of hypnozoites.

  15. Simulating Flaring Events via an Intelligent Cellular Automata Mechanism

    Dimitropoulou, M.; Vlahos, L.; Isliker, H.; Georgoulis, M.

    2010-07-01

    We simulate flaring events through a Cellular Automaton (CA) model, in which, for the first time, we use observed vector magnetograms as initial conditions. After non-linear force free extrapolation of the magnetic field from the vector magnetograms, we identify magnetic discontinuities, using two alternative criteria: (1) the average magnetic field gradient, or (2) the normalized magnetic field curl (i.e. the current). Magnetic discontinuities are identified at the grid-sites where the magnetic field gradient or curl exceeds a specified threshold. We then relax the magnetic discontinuities according to the rules of Lu and Hamilton (1991) or Lu et al. (1993), i.e. we redistribute the magnetic field locally so that the discontinuities disappear. In order to simulate the flaring events, we consider several alternative scenarios with regard to: (1) The threshold above which magnetic discontinuities are identified (applying low, high, and height-dependent threshold values); (2) The driving process that occasionally causes new discontinuities (at randomly chosen grid sites, magnetic field increments are added that are perpendicular (or may-be also parallel) to the existing magnetic field). We address the question whether the coronal active region magnetic fields can indeed be considered to be in the state of self-organized criticality (SOC).

  16. A new MODIS based approach for gas flared volumes estimation: the case of the Val d'Agri Oil Center (Southern Italy)

    Lacava, T.; Faruolo, M.; Coviello, I.; Filizzola, C.; Pergola, N.; Tramutoli, V.

    2014-12-01

    Gas flaring is one of the most controversial energetic and environmental issues the Earth is facing, moreover contributing to the global warming and climate change. According to the World Bank, each year about 150 Billion Cubic Meter of gas are being flared globally, that is equivalent to the annual gas use of Italy and France combined. Besides, about 400 million tons of CO2 (representing about 1.2% of global CO2 emissions) are added annually into the atmosphere. Efforts to evaluate the impact of flaring on the surrounding environment are hampered by lack of official information on flare locations and volumes. Suitable satellite based techniques could offers a potential solution to this problem through the detection and subsequent mapping of flare locations as well as gas emissions estimation. In this paper a new methodological approach, based on the Robust Satellite Techniques (RST), a multi-temporal scheme of satellite data analysis, was developed to analyze and characterize the flaring activity of the largest Italian gas and oil pre-treatment plant (ENI-COVA) located in Val d'Agri (Basilicata) For this site, located in an anthropized area characterized by a large environmental complexity, flaring emissions are mainly related to emergency conditions (i.e. waste flaring), being the industrial process regulated by strict regional laws. With reference to the peculiar characteristics of COVA flaring, the RST approach was implemented on 13 years of EOS-MODIS (Earth Observing System - Moderate Resolution Imaging Spectroradiometer) infrared data to detect COVA-related thermal anomalies and to develop a regression model for gas flared volume estimation. The methodological approach, the whole processing chain and the preliminarily achieved results will be shown and discussed in this paper. In addition, the possible implementation of the proposed approach on the data acquired by the SUOMI NPP - VIIRS (National Polar-orbiting Partnership - Visible Infrared Imaging

  17. Amylolytic activity of IgM and IgG antibodies from patients with multiple sclerosis.

    Saveliev, Andrew N; Ivanen, Dina R; Kulminskaya, Anna A; Ershova, Nadezhda A; Kanyshkova, Tat'yana G; Buneva, Valentina N; Mogelnitskii, Alexander S; Doronin, Boris M; Favorova, Olga O; Nevinsky, Georgy A; Neustroev, Kirill N

    2003-05-01

    IgG and IgM antibodies from the sera of patients with multiple sclerosis (MS) were found to possess amylolytic activity hydrolyzing alpha-(1-->4)-glucosyl linkages of maltooligosaccharides, glycogen, and several artificial substrates. Individual IgM fractions isolated from 54 analyzed patients with the clinically definite diagnoses of MS had approximately three orders of magnitude higher specific amylolytic activity than that for healthy donors, whereas IgG from only a few patients had high amylolytic activity. Strict criteria were used to prove that the amylolytic activity of IgMs and IgGs is their intrinsic property and is not due to any enzyme contamination. Fab fragments produced from IgM and IgG fractions of the MS patients displayed the same amylolytic activity. IgMs from various patients demonstrated different modes of action in hydrolyzing maltooligosaccharides.

  18. A giant radio flare from Cygnus X-3 with associated γ-ray emission

    Corbel, S.; Dubus, G.; Tomsick, J. A.; Szostek, A.; Corbet, R. H. D.; Miller-Jones, J. C. A.; Richards, J. L.; Pooley, G.; Trushkin, S.; Dubois, R.; Hill, A. B.; Kerr, M.; Max-Moerbeck, W.; Readhead, A. C. S.; Bodaghee, A.; Tudose, V.; Parent, D.; Wilms, J.; Pottschmidt, K.

    2012-04-01

    With frequent flaring activity of its relativistic jets, Cygnus X-3 (Cyg X-3) is one of the most active microquasars and is the only Galactic black hole candidate with confirmed high-energy γ-ray emission, thanks to detections by Fermi Large Area Telescope (Fermi/LAT) and AGILE. In 2011, Cyg X-3 was observed to transit to a soft X-ray state, which is known to be associated with high-energy γ-ray emission. We present the results of a multiwavelength campaign covering a quenched state, when radio emission from Cyg X-3 is at its weakest and the X-ray spectrum is very soft. A giant (˜20 Jy) optically thin radio flare marks the end of the quenched state, accompanied by rising non-thermal hard X-rays. Fermi/LAT observations (E≥ 100 MeV) reveal renewed γ-ray activity associated with this giant radio flare, suggesting a common origin for all non-thermal components. In addition, current observations unambiguously show that the γ-ray emission is not exclusively related to the rare giant radio flares. A three-week period of γ-ray emission is also detected when Cyg X-3 was weakly flaring in radio, right before transition to the radio quenched state. No γ-rays are observed during the ˜1-month long quenched state, when the radio flux is weakest. Our results suggest transitions into and out of the ultrasoft X-ray (radio-quenched) state trigger γ-ray emission, implying a connection to the accretion process, and also that the γ-ray activity is related to the level of radio flux (and possibly shock formation), strengthening the connection to the relativistic jets.

  19. Multiple behavior changes in diet and activity: a randomized controlled trial using mobile technology.

    Spring, Bonnie; Schneider, Kristin; McFadden, H Gene; Vaughn, Jocelyn; Kozak, Andrea T; Smith, Malaina; Moller, Arlen C; Epstein, Leonard H; Demott, Andrew; Hedeker, Donald; Siddique, Juned; Lloyd-Jones, Donald M

    2012-05-28

    Many patients exhibit multiple chronic disease risk behaviors. Research provides little information about advice that can maximize simultaneous health behavior changes. To test which combination of diet and activity advice maximizes healthy change, we randomized 204 adults with elevated saturated fat and low fruit and vegetable intake, high sedentary leisure time, and low physical activity to 1 of 4 treatments: increase fruit/vegetable intake and physical activity, decrease fat and sedentary leisure, decrease fat and increase physical activity, and increase fruit/vegetable intake and decrease sedentary leisure. Treatments provided 3 weeks of remote coaching supported by mobile decision support technology and financial incentives. During treatment, incentives were contingent on using the mobile device to self-monitor and attain behavioral targets; during follow-up, incentives were contingent only on recording. The outcome was standardized, composite improvement on the 4 diet and activity behaviors at the end of treatment and at 5-month follow-up. Of the 204 individuals randomized, 200 (98.0%) completed follow-up. The increase fruits/vegetables and decrease sedentary leisure treatments improved more than the other 3 treatments (P improved less than the other 3 treatments (P mobile technology and financial incentives holds promise to improve diet and activity. Targeting fruits/vegetables and sedentary leisure together maximizes overall adoption and maintenance of multiple healthy behavior changes.

  20. Statistical investigation of flare stars. III. Flare stars in the general galactic star field

    Mirzoyan, L.V.; Ambaryan, V.V.; Garibdzhanyan, A.T.; Mirzoyan, A.L.

    1989-01-01

    Some questions relating to the existence of a large number of flare stars in the general star field of the Galaxy are discussed. It is shown that only a small proportion of them can be found by photographic observations, and the fraction of field flare stars among such stars found in the regions of star clusters and associations does not exceed 10%. The ratio of the numbers of flare stars of the foreground and the background for a particular system depends on its distance, reaching zero at a distance of about 500 pc. The spatial density of flare stars in the Pleiades is at least two orders of magnitude greater than in the general galactic field. A lower limit for the number of flare stars in the Galaxy is estimated at 4.2 ·10 9 , and the number of nonflare red dwarfs at 2.1·10 10 . There are grounds for believing that they were all formed in star clusters and associations

  1. Legitimating New Forms of Organizing and New International Activities in the Eyes of Multiple Stakeholders

    Turcan, Romeo V.

    The research on new venture legitimation strategies is emerging; although, it is yet to form a central line of enquiry in entrepreneurship research. To contribute to this development, this paper explores the process of legitimation in a non-for-profit venture (hereafter as NGO, non-governmental...... organization). The paper explores (1) how this NGO acquired cognitive legitimacy, defined as knowledge about the new form of organizing and new activity and what is needed to succeed in respective sector, and socio-political legitimacy, defined as the value placed on the new form of organizing and new activity...... by its multiple stakeholders; and (2) what legitimation strategies it developed and adopted to legitimate itself in the eyes of its multiple stakeholders. Theoretically, the paper is grounded within legitimation theory. The empirical context is defined by a new, international NGO entering an established...

  2. Evidence from intrinsic activity that asymmetry of the human brain is controlled by multiple factors.

    Liu, Hesheng; Stufflebeam, Steven M; Sepulcre, Jorge; Hedden, Trey; Buckner, Randy L

    2009-12-01

    Cerebral lateralization is a fundamental property of the human brain and a marker of successful development. Here we provide evidence that multiple mechanisms control asymmetry for distinct brain systems. Using intrinsic activity to measure asymmetry in 300 adults, we mapped the most strongly lateralized brain regions. Both men and women showed strong asymmetries with a significant, but small, group difference. Factor analysis on the asymmetric regions revealed 4 separate factors that each accounted for significant variation across subjects. The factors were associated with brain systems involved in vision, internal thought (the default network), attention, and language. An independent sample of right- and left-handed individuals showed that hand dominance affects brain asymmetry but differentially across the 4 factors supporting their independence. These findings show the feasibility of measuring brain asymmetry using intrinsic activity fluctuations and suggest that multiple genetic or environmental mechanisms control cerebral lateralization.

  3. Computations of Photon Orbits Emitted by Flares at the ISCO of Accretion Disks Around Rotating Black Holes

    Kazanas, Demosthenes; Fukumura, K.

    2009-01-01

    We present detailed computations of photon orbits emitted by flares at the ISCO of accretion disks around rotating black holes. We show that for sufficiently large spin parameter, i.e. $a > 0.94 M$, following a flare at ISCO, a sufficient number of photons arrive at an observer after multiple orbits around the black hole, to produce an "photon echo" of constant lag, i.e. independent of the relative phase between the black hole and the observer, of $\\Delta T \\simeq 14 M$. This constant time delay, then, leads to the presence of a QPO in the source power spectrum at a frequency $\

  4. The coalescence instability in solar flares

    Tajima, T.; Brunel, F.; Sakai, J.-I.; Vlahos, L.; Kundu, M. R.

    1985-01-01

    The nonlinear coalescence instability of current carrying solar loops can explain many of the characteristics of the solar flares such as their impulsive nature, heating and high energy particle acceleration, amplitude oscillations of electromagnetic and emission as well as the characteristics of two-dimensional microwave images obtained during a flare. The plasma compressibility leads to the explosive phase of loop coalescence and its overshoot results in amplitude oscillations in temperatures by adiabatic compression and decompression. It is noted that the presence of strong electric fields and super-Alfvenic flows during the course of the instability play an important role in the production of nonthermal particles. A qualitative explanation on the physical processes taking place during the nonlinear stages of the instability is given.

  5. Microwave emission from flaring magnetic loops

    Vlahos, L.

    1980-01-01

    The microwave emission from a flaring loop is considered. In particular the author examines the question: What will be the characteristics of the radio emission at centimeter wavelengths from a small compact flaring loop when the mechanism which pumps magnetic energy into the plasma in the form of heating and/or electron acceleration satisfies the conditions: (a) the magnetic energy is released in a small volume compared to the volume of the loop, and the rate at which magnetic energy is transformed into plasma energy is faster than the energy losses from the same volume. This causes a local enhancement of the temperature by as much as one or two orders of magnitude above the coronal temperature; (b) The bulk of the energy released goes into heating the plasma and heats primarily the electrons. (Auth.)

  6. The coalescence instability in solar flares

    Tajima, T.; Brunel, F.; Sakai, J.I.; Vlahos, L.; Kundu, M.R.

    1984-01-01

    The non-linear coalescence instability of current carrying solar loops can explain many of the characteristics of the solar flares such as their impulsive nature, heating and high energy particle acceleration, amplitude oscillations of electromagnetic emission as well as the characteristics of 2-D microwave images obtained during a flare. The plasma compressibility leads to the explosive phase of loop coalescence and its overshoot results in amplitude oscillations in temperatures by adiabatic compression and decompression. We note that the presence of strong electric fields and super-Alfvenic flows during the course of the instabilty paly an important role in the production of non-thermal particles. A qualitative explanation on the physical processes taking place during the non-linear stages of the instability is given. (author)

  7. Environmental pollution due to gas flaring at Oyigbo area of Rivers State

    Avwiri, G. O.; Ebeniro, J. O.

    1996-01-01

    Environmental degradation due to oil activities in the oil rich Niger Delta of Nigeria is daily approaching a non-tolerance level. Pollutants come from various aspects of operation ranging from seismic operations through drilling to the refinery stage. Gas flared daily by Oil Companies constitute a major health hazard in this country. Environmental pollution due to gas flaring at Oyigbo area of Rivers State is hereby reported. Surface temperature-distance variations were investigated for both dry (March) and rainy (June) seasons. Physical and chemical properties of the rainwater from the areas were also measured and analysed. The results show a surface temperature elevation of about 4.1 Celsius above the mean normal diurnal temperature within a 3.00 km. radius. An average pH 4.25 was recorded thus showing the acidic nature of the environmental rainwater from the area. All other measured parameters showed serious deviations from standards. This temperature elevation and increased acidity of the rainwater have enormous influence on socio-economic lives and the activities of the populace especially on their source of income which is mainly small scale farming. It is therefore necessary that Government agencies empowered to monitor environment especially FEPA should implement all the existing legislation on gas flaring and be more involved in the design and location of gas flaring stacks. These stacks should be located at least 2 km. from towns and villages

  8. Forecasting Solar Flares Using Magnetogram-based Predictors and Machine Learning

    Florios, Kostas; Kontogiannis, Ioannis; Park, Sung-Hong; Guerra, Jordan A.; Benvenuto, Federico; Bloomfield, D. Shaun; Georgoulis, Manolis K.

    2018-02-01

    We propose a forecasting approach for solar flares based on data from Solar Cycle 24, taken by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) mission. In particular, we use the Space-weather HMI Active Region Patches (SHARP) product that facilitates cut-out magnetograms of solar active regions (AR) in the Sun in near-realtime (NRT), taken over a five-year interval (2012 - 2016). Our approach utilizes a set of thirteen predictors, which are not included in the SHARP metadata, extracted from line-of-sight and vector photospheric magnetograms. We exploit several machine learning (ML) and conventional statistics techniques to predict flares of peak magnitude {>} M1 and {>} C1 within a 24 h forecast window. The ML methods used are multi-layer perceptrons (MLP), support vector machines (SVM), and random forests (RF). We conclude that random forests could be the prediction technique of choice for our sample, with the second-best method being multi-layer perceptrons, subject to an entropy objective function. A Monte Carlo simulation showed that the best-performing method gives accuracy ACC=0.93(0.00), true skill statistic TSS=0.74(0.02), and Heidke skill score HSS=0.49(0.01) for {>} M1 flare prediction with probability threshold 15% and ACC=0.84(0.00), TSS=0.60(0.01), and HSS=0.59(0.01) for {>} C1 flare prediction with probability threshold 35%.

  9. Solar Flare Super-Events: When they Can Occur and the Energy Limits of their Realization

    Ishkov, Vitaly N.

    2015-03-01

    For the successful development of terrestrial civilization it is necessary to estimate the space factors, including phenomena on Sun, which can ruin it or cause such catastrophic loss, that the restoration to the initial level can take unacceptably long time. Super-powerful solar flares are the only such phenomena. Therefore an attempt is undertaken to estimate the possibility of such super-event occurrence at this stage of our star evolution. Since solar flare events are the consequence of the newly emerging magnetic fluxes interacting with the already existing magnetic fields of active regions, are investigated the observed cases which lead to the realization of such super-events. From the observations of the maximal magnetic fluxes during the period of reliable solar observations, the conclusion is made that the super- extreme solar flares cannot significantly exceed the most powerful solar flares which have already been observed. On the statistics of the reliable solar cycles the sunspot groups, in which occurred the most powerful solar super-events (August- September 1859 - solar cycle 10; June 1991 - SC 22; October-November 2003 - SC 23) appeared in the periods of the solar magnetic field reorganization between the epochs of "increased" and "lowered" solar activity.

  10. Multiple containment for LSA [low specific activity] and SCO [surface contaminated objects] wastes

    Burgess, M.H.

    1993-09-01

    Radioactive wastes are generally transported in the form of Low Specific Activity (LSA) materials or Surface Contaminated Objects (SCO). This report proposes that a method of acknowledging the beneficial effects of multiple containment for such wastes should be written into the 1996 Edition of the IAEA Transport Regulations. Experience used to assess risks from on-site movements of radioactive material in the UK can be applied to develop safety arguments justifying the alleviation of off-site transport risks. (UK)

  11. Evidence from intrinsic activity that asymmetry of the human brain is controlled by multiple factors

    Liu, Hesheng; Stufflebeam, Steven M.; Sepulcre, Jorge; Hedden, Trey; Buckner, Randy L.

    2009-01-01

    Cerebral lateralization is a fundamental property of the human brain and a marker of successful development. Here we provide evidence that multiple mechanisms control asymmetry for distinct brain systems. Using intrinsic activity to measure asymmetry in 300 adults, we mapped the most strongly lateralized brain regions. Both men and women showed strong asymmetries with a significant, but small, group difference. Factor analysis on the asymmetric regions revealed 4 separate factors that each ac...

  12. Aging causes decreased resistance to multiple stresses and a failure to activate specific stress response pathways

    Dues, Dylan J.; Andrews, Emily K.; Schaar, Claire E.; Bergsma, Alexis L.; Senchuk, Megan M.; Van Raamsdonk, Jeremy M.

    2016-01-01

    In this work, we examine the relationship between stress resistance and aging. We find that resistance to multiple types of stress peaks during early adulthood and then declines with age. To dissect the underlying mechanisms, we use C. elegans transcriptional reporter strains that measure the activation of different stress responses including: the heat shock response, mitochondrial unfolded protein response, endoplasmic reticulum unfolded protein response, hypoxia response, SKN-1-mediated oxi...

  13. Theoretical and observational assessments of flare efficiencies

    Leahey, D.M.; Preston, K.; Strosher, M.

    2000-01-01

    During the processing of hydrocarbon materials, gaseous wastes are flared in an effort to completely burn the waste material and therefore leave behind very little by-products. Complete combustion, however is rarely successful because entrainment of air into the region of combusting gases restricts flame sizes to less than optimum values. The resulting flames are often too small to dissipate the amount of heat associated with complete (100 per cent) combustion efficiency. Flaring, therefore, often results in emissions of gases with more complex molecular structures than just carbon dioxide and water. Polycyclic aromatic hydrocarbons and volatile organic compounds which are indicative of incomplete combustion are often associated with flaring. This theoretical study of flame efficiencies was based on the knowledge of the full range of chemical reactions and associated kinetics. In this study, equations developed by Leahey and Schroeder were used to estimate flame lengths, areas and volumes as functions of flare stack exit velocity, stoichiometric mixing ratio and wind speed. This was followed by an estimate of heats released as part of the combustion process. This was derived from the knowledge of the flame dimensions together with an assumed flame temperature of 1200 K. Combustion efficiencies were then obtained by taking the ratio of estimated actual heat release values to those associated with complete combustion. It was concluded that combustion efficiency decreases significantly with wind speed increases from 1 to 6 m/s. After that initial increase, combustion efficiencies level off at values between 10 to 15 per cent. Propane and ethane were found to burn more efficiently than methane or hydrogen sulfide. 24 refs., 4 tabs., 1 fig., 1 append

  14. Sunspot waves and flare energy release

    Sych, R.A.; Karlický, Marian; Altyntsev, A.; Dudík, Jaroslav; Kashapova, L. K.

    2015-01-01

    Roč. 577, May (2015), A43/1-A43/8 ISSN 0004-6361 R&D Projects: GA ČR GAP209/12/0103; GA ČR GAP209/12/1652 Grant - others:EC(XE) 606862 Program:FP7 Institutional support: RVO:67985815 Keywords : Sun flares * Sun oscillations * Sun X-rays Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  15. A COLD FLARE WITH DELAYED HEATING

    Fleishman, Gregory D.; Pal'shin, Valentin D.; Lysenko, Alexandra L.; Meshalkina, Natalia; Kashapova, Larisa K.; Altyntsev, Alexander T.

    2016-01-01

    Recently, a number of peculiar flares have been reported that demonstrate significant nonthermal particle signatures with low, if any, thermal emission, which implies a close association of the observed emission with the primary energy release/electron acceleration region. This paper presents a flare that appears “cold” at the impulsive phase, while displaying delayed heating later on. Using hard X-ray data from Konus- Wind , microwave observations by SSRT, RSTN, NoRH, and NoRP, context observations, and three-dimensional modeling, we study the energy release, particle acceleration, and transport, and the relationships between the nonthermal and thermal signatures. The flaring process is found to involve the interaction between a small loop and a big loop with the accelerated particles divided roughly equally between them. Precipitation of the electrons from the small loop produced only a weak thermal response because the loop volume was small, while the electrons trapped in the big loop lost most of their energy in the coronal part of the loop, which resulted in coronal plasma heating but no or only weak chromospheric evaporation, and thus unusually weak soft X-ray emission. The energy losses of the fast electrons in the big tenuous loop were slow, which resulted in the observed delay of the plasma heating. We determined that the impulsively accelerated electron population had a beamed angular distribution in the direction of the electric force along the magnetic field of the small loop. The accelerated particle transport in the big loop was primarily mediated by turbulent waves, which is similar to other reported cold flares.

  16. The Discriminant Analysis Flare Forecasting System (DAFFS)

    Leka, K. D.; Barnes, Graham; Wagner, Eric; Hill, Frank; Marble, Andrew R.

    2016-05-01

    The Discriminant Analysis Flare Forecasting System (DAFFS) has been developed under NOAA/Small Business Innovative Research funds to quantitatively improve upon the NOAA/SWPC flare prediction. In the Phase-I of this project, it was demonstrated that DAFFS could indeed improve by the requested 25% most of the standard flare prediction data products from NOAA/SWPC. In the Phase-II of this project, a prototype has been developed and is presently running autonomously at NWRA.DAFFS uses near-real-time data from NOAA/GOES, SDO/HMI, and the NSO/GONG network to issue both region- and full-disk forecasts of solar flares, based on multi-variable non-parametric Discriminant Analysis. Presently, DAFFS provides forecasts which match those provided by NOAA/SWPC in terms of thresholds and validity periods (including 1-, 2-, and 3- day forecasts), although issued twice daily. Of particular note regarding DAFFS capabilities are the redundant system design, automatically-generated validation statistics and the large range of customizable options available. As part of this poster, a description of the data used, algorithm, performance and customizable options will be presented, as well as a demonstration of the DAFFS prototype.DAFFS development at NWRA is supported by NOAA/SBIR contracts WC-133R-13-CN-0079 and WC-133R-14-CN-0103, with additional support from NASA contract NNH12CG10C, plus acknowledgment to the SDO/HMI and NSO/GONG facilities and NOAA/SWPC personnel for data products, support, and feedback. DAFFS is presently ready for Phase-III development.

  17. Two zebrafish G2A homologs activate multiple intracellular signaling pathways in acidic environment

    Ichijo, Yuta; Mochimaru, Yuta [Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571 (Japan); Azuma, Morio [Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama 930-8555 (Japan); Satou, Kazuhiro; Negishi, Jun [Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571 (Japan); Nakakura, Takashi [Department of Anatomy, Graduate School of Medicine, Teikyo University, 2-11-1 Itabashi-Ku, Tokyo 173-8605 (Japan); Oshima, Natsuki [Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571 (Japan); Mogi, Chihiro; Sato, Koichi [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512 (Japan); Matsuda, Kouhei [Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama 930-8555 (Japan); Okajima, Fumikazu [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512 (Japan); Tomura, Hideaki, E-mail: tomurah@meiji.ac.jp [Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571 (Japan)

    2016-01-01

    Human G2A is activated by various stimuli such as lysophosphatidylcholine (LPC), 9-hydroxyoctadecadienoic acid (9-HODE), and protons. The receptor is coupled to multiple intracellular signaling pathways, including the G{sub s}-protein/cAMP/CRE, G{sub 12/13}-protein/Rho/SRE, and G{sub q}-protein/phospholipase C/NFAT pathways. In the present study, we examined whether zebrafish G2A homologs (zG2A-a and zG2A-b) could respond to these stimuli and activate multiple intracellular signaling pathways. We also examined whether histidine residue and basic amino acid residue in the N-terminus of the homologs also play roles similar to those played by human G2A residues if the homologs sense protons. We found that the zG2A-a showed the high CRE, SRE, and NFAT activities, however, zG2A-b showed only the high SRE activity under a pH of 8.0. Extracellular acidification from pH 7.4 to 6.3 ameliorated these activities in zG2A-a-expressing cells. On the other hand, acidification ameliorated the SRE activity but not the CRE and NFAT activities in zG2A-b-expressing cells. LPC or 9-HODE did not modify any activity of either homolog. The substitution of histidine residue at the 174{sup th} position from the N-terminus of zG2A-a to asparagine residue attenuated proton-induced CRE and NFAT activities but not SRE activity. The substitution of arginine residue at the 32nd position from the N-terminus of zG2A-a to the alanine residue also attenuated its high and the proton-induced CRE and NFAT activities. On the contrary, the substitution did not attenuate SRE activity. The substitution of the arginine residue at the 10th position from the N-terminus of zG2A-b to the alanine residue also did not attenuate its high or the proton-induced SRE activity. These results indicate that zebrafish G2A homologs were activated by protons but not by LPC and 9-HODE, and the activation mechanisms of the homologs were similar to those of human G2A. - Highlights: • Zebrafish two G2A homologs are proton

  18. Underground Storage Alternative To Nigeria's Gas Flaring

    Obi, A.I

    2004-01-01

    Energy demands are increasing as the world's population of energy users grows. At the same time many nations want to decommission nuclear plants in support of a cleaner environment. Clean burning natural gas is the fuel most likely to meet society's complex requirements. Demand for natural gas will rise more strongly than for any fossil fuel. The utilization of the huge gas resources form the petroleum deposit in the Niger Delta area is the major problem confronting the oil/gas industry in Nigeria and the disposal of associated gas has been a major challenge for the barrel of oil; hence with oil production of about 2.0 million barrels per day, some 2.0 billion standard cubic feet of AG is producing everyday. An alarming proportion of the gas is wasted by flaring, while very small proportion is used by oil-producing companies and other most alarming rate of flaring in the world compared with other oil/gas producing countries. This paper highlights the numerous benefits accruing from proper utilization of natural gas using SASOL of South Africa as an example and recommends underground storage of natural gas as an industry that will help check flaring, meet fluctuating demand and create wealth for the nation

  19. Acceleration of runaway electrons in solar flares

    Moghaddam-Taaheri, E.; Goertz, C. K.

    1990-01-01

    The dc electric field acceleration of electrons out of a thermal plasma and the evolution of the runaway tail are studied numerically, using a relativistic quasi-linear code based on the Ritz-Galerkin method and finite elements. A small field-aligned electric field is turned on at a certain time. The resulting distribution function from the runaway process is used to calculate the synchrotron emission during the evolution of the runaway tail. It is found that, during the runaway tail formation, which lasts a few tens of seconds for typical solar flare conditions, the synchrotron emission level is low, almost ot the same order as the emission from the thermal plasma, at the high-frequency end of the spectrum. However, the emission is enhanced explosively in a few microseconds by several orders of magnitude at the time the runaway tail stops growing along the magnetic field and tends toward isotropy due to the pitch-angle scattering of the fast particles. Results indicate that, in order to account for the observed synchrotron emission spectrum of a typical solar flare, the electric field acceleration phase must be accompanied or preceded by a heating phase which yields an enhanced electron temperature of about 2-15 keV in the flare region if the electric field is 0.1-0.2 times the Dreicer field and cyclotron-to-plasma frequency ratios are of order 1-2.

  20. Solar flare pion and neutron production

    Forrest, D.J.; Vestrand, W.T.

    1992-01-01

    During cycle 21, the Gamma Ray Spectrometer on SMM observed three large flares with clear evidence for pion decay gamma rays and high energy neutrons. Two of these had an extended emission phase. The emission observed in these extended phases were clearly different from those observed in the impulsive phase. Compared to the impulsive phase, the extended phase emissions were strongly deficient in electron bremsstrahlung relative to the nuclear line emission in the 1.0-7.0 MeV band and appeared to have a reduced energetic neutron to pion gamma ray emission in the >10 MeV band. These changes can be produced either by a strong hardening of the accelerated ion spectrum together with a relative decrease in the energetic electron spectrum, or by a pronounced change in the geometry of the particle spectrum downwards towards the photosphere. The authors review the observational evidence in terms of these two possibilities. A dramatic change in the energetic particle geometry appears to offer the simplest explanation. If true these two flares represent the first clear evidence of strong particle geometry effects within individual flares

  1. Anomalous Temporal Behaviour of Broadband Ly Alpha Observations During Solar Flares from SDO/EVE

    Milligan, Ryan O.; Chamberlin, Phillip C.

    2016-01-01

    Although it is the most prominent emission line in the solar spectrum, there has been a notable lack of studies devoted to variations in Lyman-alpha (Ly-alpha) emission during solar flares in recent years. However, the few examples that do exist have shown Ly-alpha emission to be a substantial radiator of the total energy budget of solar flares (of the order of 10 percent). It is also a known driver of fluctuations in the Earth's ionosphere. The EUV (Extreme Ultra-Violet) Variability Experiment (EVE) on board the Solar Dynamics Observatory (SDO) now provides broadband, photometric Ly-alpha data at 10-second cadence with its Multiple EUV Grating Spectrograph-Photometer (MEGS-P) component, and has observed scores of solar flares in the 5 years since it was launched. However, the MEGS-P time profiles appear to display a rise time of tens of minutes around the time of the flare onset. This is in stark contrast to the rapid, impulsive increase observed in other intrinsically chromospheric features (H-alpha, Ly-beta, LyC, C III, etc.). Furthermore, the emission detected by MEGS-P peaks around the time of the peak of thermal soft X-ray emission and not during the impulsive phase when energy deposition in the chromosphere (often assumed to be in the form of non-thermal electrons) is greatest. The time derivative of Ly-alpha lightcurves also appears to resemble that of the time derivative of soft X-rays, reminiscent of the Neupert effect. Given that spectrally-resolved Ly-alpha observations during flares from SORCE / SOLSTICE (Solar Radiation and Climate Experiment / Solar Stellar Irradiance Comparison Experiment) peak during the impulsive phase as expected, this suggests that the atypical behaviour of MEGS-P data is a manifestation of the broadband nature of the observations. This could imply that other lines andor continuum emission that becomes enhanced during flares could be contributing to the passband. Users are hereby urged to exercise caution when interpreting

  2. Identical parallel machine scheduling with nonlinear deterioration and multiple rate modifying activities

    Ömer Öztürkoğlu

    2017-07-01

    Full Text Available This study focuses on identical parallel machine scheduling of jobs with deteriorating processing times and rate-modifying activities. We consider non linearly increasing processing times of jobs based on their position assignment. Rate modifying activities are also considered to recover the increase in processing times of jobs due to deterioration. We also propose heuristics algorithms that rely on ant colony optimization and simulated annealing algorithms to solve the problem with multiple RMAs in a reasonable amount of time. Finally, we show that ant colony optimization algorithm generates close optimal solutions and superior results than simulated annealing algorithm.

  3. Developing a questionnaire on physical activity support of people with (profound) intellectual (and multiple) disabilities : Experiences from the Netherlands

    Bossink, Leontien; van der Putten, Annette; Vlaskamp, Carla

    2017-01-01

    Introduction: People with intellectual disabilities (ID) undertake extremely low levels of physical activity, which is even more true in people with profound intellectual and multiple disabilities (PIMD). Physical activity approaches, particularly for people with PIMD, are more likely to be

  4. Social Cognitive Correlates of Physical Activity in Black Individuals With Multiple Sclerosis.

    Kinnett-Hopkins, Dominique; Motl, Robert W

    2016-04-01

    To examine variables from social cognitive theory as correlates of physical activity in black and white individuals with multiple sclerosis (MS). Cross-sectional. National survey. Black (n=151) and white (n=185) individuals with MS were recruited through the North American Research Committee on Multiple Sclerosis Registry. Not applicable. The battery of questionnaires included information on demographic and clinical characteristics, physical activity, exercise self-efficacy, function, social support, exercise outcome expectations, and exercise goal setting and planning. Black individuals with MS reported significantly lower levels of physical activity compared with white individuals with MS. Physical activity levels were significantly correlated with self-efficacy, outcome expectations, functional limitations as impediments, and goal setting in black participants with MS. The pattern and magnitude of correlations were comparable with those observed in white participants based on Fisher z tests. Researchers should consider applying behavioral interventions that target social cognitive theory variables for increasing physical activity levels among black individuals with MS. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  5. Incidence and factors associated with flare-ups in a post graduate programme in the indian population.

    Pamboo, Jaya; Hans, Manoj-Kumar; Kumaraswamy, Bangalore-Niranjan; Chander, Subhash; Bhaskaran, Sajeev

    2014-12-01

    The study had twin objectives: to assess the incidence of flare-ups (a severe problem requiring an unscheduled visit and treatment) among patients who received endodontic treatment in the Department of Conservative Dentistry and Endodontics in Vyas Dental college and hospital, Jodhpur during a period of one year, and also to examine the correlation with pre-operative and operative variables. Data was collected from 1023 teeth from 916 patients who had received endodontic treatment over a 12- month period. Information was obtained for each patient treated, including pulp and peri-radicular diagnosis for the tooth, presence of pre-operatory pain, type of medication being used, type of instrumentation technique used and number of appointments needed to complete the root canal treatment. The results showed an incidence of 2.35% for flare-ups from 1023 endodontically treated teeth. Statistical analysis was done using the chi-square test. Flare-ups were found to be affected significantly by gender of patient, presence of radiolucent lesions, patients taking pre-operative analgesic or anti-inflammatory drugs and on type of instrumentation technique. In contrast, there was no correlation between flare-ups and age, different arch/tooth groups and single or multiple visit endodontics. Key words:Anti-inflammatory, flare-ups, instrumentation, prospective.

  6. Spots and White Light Flares in an L Dwarf

    2013-01-01

    Program GN-2012A-Q-37) GMOS spectrograph (Hook et al. 2004) when a series of flares occurred. A spectrum of the most powerful flare in its impulsive...10:14 Hα HeI HeI HeI OI Fig. 4. Gemini-North GMOS spectra of W1906+40 in quiescence (below) and in flare. Note the broad Hα, atomic emission lines

  7. Mental Health in Multiple Sclerosis Patients without Limitation of Physical Function: The Role of Physical Activity

    Alexander Tallner

    2015-07-01

    Full Text Available Multiple sclerosis (MS patients, in general, show reduced physical function, physical activity, and quality of life. Positive associations between physical activity and quality of life have been reported. In particular, we were interested in the relation between physical activity and mental health in MS patients without limitation of physical function, since limitations of physical function may influence both physical activity and quality of life. Assessment comprised the Baecke questionnaire on physical activity, the Short Form 36 Health Survey (SF-36, and Beck Depression Inventory (BDI. We ranked our sample according to physical activity into four groups and performed an ANOVA to analyze the relationship between levels of physical activity and health-related quality of life (HRQoL. Then we performed a subgroup analysis and included patients with unlimited walking distance and a score of less than 18 in the BDI. Most active vs. inactive patients were compared for the mental subscales of the SF-36 and depression scores. From 632 patients, 265 met inclusion criteria and hence quartiles were filled with 67 patients each. Active and inactive patients did not differ considerably in physical function. In contrast, mental subscales of the SF-36 were higher in active patients. Remarkable and significant differences were found regarding vitality, general health perception, social functioning and mental health, all in favor of physically active patients. Our study showed that higher physical activity is still associated with higher mental health scores even if limitations of physical function are accounted for. Therefore, we believe that physical activity and exercise have considerable health benefits for MS patients.

  8. Imaging Surrogates of Disease Activity in Neuromyelitis Optica Allow Distinction from Multiple Sclerosis.

    Matthews, Lucy; Kolind, Shannon; Brazier, Alix; Leite, Maria Isabel; Brooks, Jonathan; Traboulsee, Anthony; Jenkinson, Mark; Johansen-Berg, Heidi; Palace, Jacqueline

    2015-01-01

    Inflammatory demyelinating lesions of the central nervous system are a common feature of both neuromyelitis optica and multiple sclerosis. Despite this similarity, it is evident clinically that the accumulation of disability in patients with neuromyelitis optica is relapse related and that a progressive phase is very uncommon. This poses the question whether there is any pathological evidence of disease activity or neurodegeneration in neuromyelitis optica between relapses. To investigate this we conducted a longitudinal advanced MRI study of the brain and spinal cord in neuromyelitis optica patients, comparing to patients with multiple sclerosis and controls. We found both cross-sectional and longitudinal evidence of diffusely distributed neurodegenerative surrogates in the multiple sclerosis group (including thalamic atrophy, cervical cord atrophy and progressive widespread diffusion and myelin water imaging abnormalities in the normal appearing white matter) but not in those with neuromyelitis optica, where localised abnormalities in the optic radiations of those with severe visual impairment were noted. In addition, between relapses, there were no new silent brain lesions in the neuromyelitis optica group. These findings indicate that global central nervous system neurodegeneration is not a feature of neuromyelitis optica. The work also questions the theory that neurodegeneration in multiple sclerosis is a chronic sequela to prior inflammatory and demyelinating pathology, as this has not been found to be the case in neuromyelitis optica where the lesions are often more destructive.

  9. Imaging Surrogates of Disease Activity in Neuromyelitis Optica Allow Distinction from Multiple Sclerosis.

    Lucy Matthews

    Full Text Available Inflammatory demyelinating lesions of the central nervous system are a common feature of both neuromyelitis optica and multiple sclerosis. Despite this similarity, it is evident clinically that the accumulation of disability in patients with neuromyelitis optica is relapse related and that a progressive phase is very uncommon. This poses the question whether there is any pathological evidence of disease activity or neurodegeneration in neuromyelitis optica between relapses. To investigate this we conducted a longitudinal advanced MRI study of the brain and spinal cord in neuromyelitis optica patients, comparing to patients with multiple sclerosis and controls. We found both cross-sectional and longitudinal evidence of diffusely distributed neurodegenerative surrogates in the multiple sclerosis group (including thalamic atrophy, cervical cord atrophy and progressive widespread diffusion and myelin water imaging abnormalities in the normal appearing white matter but not in those with neuromyelitis optica, where localised abnormalities in the optic radiations of those with severe visual impairment were noted. In addition, between relapses, there were no new silent brain lesions in the neuromyelitis optica group. These findings indicate that global central nervous system neurodegeneration is not a feature of neuromyelitis optica. The work also questions the theory that neurodegeneration in multiple sclerosis is a chronic sequela to prior inflammatory and demyelinating pathology, as this has not been found to be the case in neuromyelitis optica where the lesions are often more destructive.

  10. Endodontic flare up: incidence and association of possible risk factors.

    Gbadebo, S O; Sulaiman, A O; Anifowose, O O

    2016-06-01

    Endodontic emergency during root canal treatment (flare up) is a common occurrence in multivisit root canal treatment (RCT) and it may be associated with many factors. The occurrence however can affect the prognosis of the tooth and the patient -clinician relationship. To determine the incidence and risk factors associated with occurrence of flare up in a multi visit RCT. Patients planned for multi-visit (RCT) were recruited for the research. Standard protocol was followed in all cases. After the first visit, the patients were followed up for possible development of flare up. Patients' demographics, presence or absence of preoperative pain, status of the pulp and occurrence of flare up were among the data collected. Data was analyzed using SPSS version 20 with level of significance set at P flare up was 8.5%. Prior to treatment, 47% of the cases had pain, 61.3% had apical radioluscency and 83% had pulpal necrosis. Majority (7, 77.8%) of the flare up occurred after the first visit (p=0.000). Only pre- treatment pain had a statistical significant ielationship with occurrence of flare up (p=0.009). Incidence of flare up was 8.5% and the major risk factor was preoperative pain. First visit in a multi visit RCT is an important stage which if well handled, can reduce the incidence of flare up.

  11. Variation of the solar wind velocity following solar flares

    Huang, Y.; Lee, Y.

    1975-01-01

    By use of the superposed epoch method, changes in the solar wind velocity following solar flares have been investigated by using the solar wind velocity data obtained by Pioneer 6 and 7 and Vela 3, 4, and 5 satellites. A significant increase of the solar wind velocity has been found on the second day following importance 3 solar flares and on the third day following importance 2 solar flares. No significant increase of the solar wind velocity has been found for limb flares. (auth)

  12. Imaging Observations of Magnetic Reconnection in a Solar Eruptive Flare

    Li, Y.; Ding, M. D.; Sun, X.; Qiu, J.; Priest, E. R.

    2017-01-01

    Solar flares are among the most energetic events in the solar atmosphere. It is widely accepted that flares are powered by magnetic reconnection in the corona. An eruptive flare is usually accompanied by a coronal mass ejection, both of which are probably driven by the eruption of a magnetic flux rope (MFR). Here we report an eruptive flare on 2016 March 23 observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory . The extreme-ultraviolet imaging observations exhibit the clear rise and eruption of an MFR. In particular, the observations reveal solid evidence of magnetic reconnection from both the corona and chromosphere during the flare. Moreover, weak reconnection is observed before the start of the flare. We find that the preflare weak reconnection is of tether-cutting type and helps the MFR to rise slowl