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Sample records for active regions sudden

  1. Thermal and dynamical perturbations in the winter polar mesosphere-lower thermosphere region associated with sudden stratospheric warmings under conditions of low solar activity

    NASA Astrophysics Data System (ADS)

    Lukianova, Renata; Kozlovsky, Alexander; Shalimov, Sergey; Ulich, Thomas; Lester, Mark

    2015-06-01

    The upper mesospheric neutral winds and temperatures have been derived from continuous meteor radar (MR) measurements over Sodankyla, Finland, in 2008-2014. Under conditions of low solar activity pronounced sudden mesospheric coolings linked to the major stratospheric warming (SSW) in 2009 and a medium SSW in 2010 are observed while there is no observed thermal signature of the major SSW in 2013 occurred during the solar maximum. Mesosphere-ionosphere anomalies observed simultaneously by the MR, the Aura satellite, and the rapid-run ionosonde during a period of major SSW include the following features. The mesospheric temperature minimum occurs 1 day ahead of the stratospheric maximum, and the mesospheric cooling is almost of the same value as the stratospheric warming (~50 K), the former decay faster than the latter. In the course of SSW, a strong mesospheric wind shear of ~70 m/s/km occurs. The wind turns clockwise (anticlockwise) from north-eastward (south-eastward) to south-westward (north-westward) above (below) 90 km. As the mesospheric temperature reaches its minimum, the gravity waves (GW) in the ionosphere with periods of 10-60 min decay abruptly while the GWs with longer periods are not affected. The effect is explained by selective filtering and/or increased turbulence near the mesopause.

  2. Sudden unexpected death in epileptics following sudden, intense, increases in geomagnetic activity: Prevalence of effect and potential mechanisms

    NASA Astrophysics Data System (ADS)

    Persinger, M. A.; Psych, C.

    1995-12-01

    Abrupt, intense increases in global geomagnetic activity during the local night may precipitate a significant proportion of sudden unexpected (or unexplained) deaths (SUD) in epileptics. Over a 2-year period SUD in healthy chronic epileptic rats occurred when the average daily geomagnetic activity exceeded 50 nT (nanoTesla) and suddenly began during local night. Other experiments demonstrated that epileptic rats displayed more spontaneous seizures per night if there had been sudden increases in geomagnetic activity. Analyses of previously published data indicated that the number of SUDs/month in a population of human epileptics was positively associated with the number of days/month when the average geomagnetic activity exceeded 50 nT. The results support the hypothesis that suppression of the nocturnal concentrations of the endogenous anticonvulsant melatonin by sudden increases in geomagnetic activity may encourage fatal cardiac arrhythmias by uncoupling the insular/amygdaloid-paraventricular hypothalamic-solitary nucleus pathways.

  3. Exploring Sudden Gains in Behavioral Activation Therapy for Major Depressive Disorder

    PubMed Central

    Hunnicutt-Ferguson, Kallio; Hoxha, Denada; Gollan, Jackie

    2012-01-01

    Understanding the onset and course of sudden gains in treatment provides clinical information to the patient and clinician, and encourages clinicians to strive for these sudden clinical gains with their patients. This study characterizes the occurrence of sudden gains with Behavioral Activation (BA; Martell, Addis, & Jacobson, 2001), and the extent to which pre-treatment dysfunctional depressive thinking predicts sudden gains during treatment. We enrolled a sample of adults (n = 42) between ages 18–65 diagnosed with primary Major Depressive Disorder. All participants completed a 16-week course of BA, with clinical and self-report assessments at pre-, mid- and post-treatment. Results indicated that sudden gain and non-sudden gain participants showed differential improvement across treatment. No significant effects emerged for the dysfunctional cognitive style as a predictor of sudden gain status. Sudden gains may result from interaction of non-specific factors with the BA techniques implemented during early phases of therapy. PMID:22336434

  4. Incidence of Sudden Cardiac Death in a Young Active Population

    PubMed Central

    Farioli, Andrea; Christophi, Costas A; Quarta, Candida Cristina; Kales, Stefanos N

    2015-01-01

    Background Little is known about the burden of sudden cardiac death (SCD) among active, presumably healthy persons. We investigated the incidence of SCD among US male career firefighters. Methods and Results All on-duty SCDs among US male career firefighters between 1998 and 2012 were identified from the US Fire Administration and the US National Institute for Occupational Safety and Health databases. Age-specific incidence rates (IRs) of SCD with 95% CIs were computed. A joinpoint model was fitted to analyze the trend in IR and to help estimate the annual percentage change of SCD rates over the years. The effects of seasonality were assessed through a Poisson regression model. We identified 182 SCDs; based on 99 available autopsy reports, the leading underlying cause of death was coronary heart disease (79%). The overall IR was 18.1 SCDs per 100 000 person-years. The age-specific IRs of SCD ranged between 3.8 (for those aged 18 to 24 years) and 45.2 (for those aged 55 to 64 years) per 100 000 person-years. The annual rate of SCD steadily declined over time (annual percentage change −3.9%, 95% CI −5.8 to −2.0). SCD events were more frequent during January (peak-to-low ratio 1.70; 95% CI 1.09 to 2.65). In addition, the IR was 3 times higher during high-risk duties compared with low-risk duties. IRs among firefighters were lower than those observed among the US general population and US military personnel. Conclusions SCD risk in this active working population is overestimated using statistics from the general population. To address public health questions among these subpopulations, more specific studies of active adults should be conducted. PMID:26066031

  5. Sudden Cardiac Arrest During Sports Activity in Middle Age

    PubMed Central

    Marijon, Eloi; Uy-Evanado, Audrey; Reinier, Kyndaron; Teodorescu, Carmen; Narayanan, Kumar; Jouven, Xavier; Gunson, Karen; Jui, Jonathan; Chugh, Sumeet S.

    2015-01-01

    Background Sports-associated sudden cardiac arrests (SCAs) occur mostly during middle age. We sought to determine burden, characteristics, and outcomes of SCA during sports among middle aged residents of a large US community. Methods and Results SCA cases aged 35–65 years were identified in a large, prospective, population-based study (2002–2013), with systematic and comprehensive assessment of their lifetime medical history. Of the 1,247 SCA cases, 63 (5%) occurred during sports activities at a mean age of 51.1±8.8 years, yielding an incidence of 21.7 (95%CI 8.1–35.4) per million per year. The incidence varied significantly based on sex, with a higher incidence among men (RR 18.68 95%CI 2.50–139.56) for sports SCA, as compared to all other SCA (RR 2.58, 95%CI 2.12–3.13). Sports SCA was also more likely to be a witnessed event (87 vs. 53%, P<0.001), with cardiopulmonary resuscitation (44 vs. 25%, P=0.001) and ventricular fibrillation (84 vs. 51%, P<0.0001). Survival to hospital discharge was higher for sports-associated SCA (23.2 vs. 13.6%, P=0.04). Sports SCA cases presented with known pre-existing cardiac disease in 16%, ≥1 cardiovascular risk factor in 56%, and overall, 36% of cases had typical cardiovascular symptoms during the week preceding SCA. Conclusions Sports-associated SCA in middle age represents a relatively small proportion of the overall SCA burden, reinforcing the idea of the high benefit-low risk nature of sports activity. Especially in light of current population aging trends, our findings emphasize that targeted education could maximize both safety and acceptance of sports activity in the older athlete. PMID:25847988

  6. Sudden synchrony leaps accompanied by frequency multiplications in neuronal activity

    PubMed Central

    Vardi, Roni; Goldental, Amir; Guberman, Shoshana; Kalmanovich, Alexander; Marmari, Hagar; Kanter, Ido

    2013-01-01

    A classical view of neural coding relies on temporal firing synchrony among functional groups of neurons, however, the underlying mechanism remains an enigma. Here we experimentally demonstrate a mechanism where time-lags among neuronal spiking leap from several tens of milliseconds to nearly zero-lag synchrony. It also allows sudden leaps out of synchrony, hence forming short epochs of synchrony. Our results are based on an experimental procedure where conditioned stimulations were enforced on circuits of neurons embedded within a large-scale network of cortical cells in vitro and are corroborated by simulations of neuronal populations. The underlying biological mechanisms are the unavoidable increase of the neuronal response latency to ongoing stimulations and temporal or spatial summation required to generate evoked spikes. These sudden leaps in and out of synchrony may be accompanied by multiplications of the neuronal firing frequency, hence offering reliable information-bearing indicators which may bridge between the two principal neuronal coding paradigms. PMID:24198764

  7. The potential of cellular network infrastructures for sudden rainfall monitoring in dry climate regions

    NASA Astrophysics Data System (ADS)

    David, N.; Alpert, P.; Messer, H.

    2013-09-01

    Monitoring of precipitation and in particular sudden rain, in rural dry climate regions, is a subject of great significance in several weather related processes such as soil erosion, flash flooding, triggering epidemics and more. The rainfall monitoring facilities in these regions and as a result precipitation data are, however, commonly, severely lacking. As was recently shown, cellular networks infrastructures supply high resolution precipitation measurements at ground level while often being situated in dry areas, covering large parts of these climatic zones. The potential found in these systems to provide early monitoring and essential precipitation information, directly from arid regions, based on standard measurements of commercial microwave links, is exemplified here over the Negev and the Southern Judean desert, South Israel. We present the results of two different rainfall events occurred in these regions. It is shown that the microwave system measured precipitation between at least 50 min (in case 1) and at least 1 h and 40 min (in case 2) before each of the sparse rain gauges. During each case, the radar system, located relatively far from the arid sites, provided measurements from heights of at least 1500 m and 2000 m above surface, respectively. A third case study demonstrates a relative advantage of microwave links to measure precipitation intensity with respect to the radar system, over an area of complex topography located in northeastern Israel, which is relatively far (~ 150 km) from the radar.

  8. Chronic neck pain alters muscle activation patterns to sudden movements.

    PubMed

    Boudreau, Shellie A; Falla, Deborah

    2014-06-01

    The aim of this study was to assess the activation of the sternocleidomastoid (SCM) and splenius capitis (SC) muscles in response to unanticipated, full body perturbations in individuals with chronic neck pain (NP) and age-matched healthy controls (HC). Individuals with NP had a history of NP for 8.9 ± 7.8 years, rated the intensity of NP as 4.2 ± 2.0 (score out of 10), and scored 15.3 ± 6.5 on the Neck Disability Index. Participants stood on a moveable platform during which 32 randomized postural perturbations (eight repetitions of four perturbation types: 8 cm forward slide (FS), 8 cm backward slides, 10° forward tilt, and 10° backward tilt) with varying inter-perturbation time intervals were performed over a period of 5 min. Bilateral surface electromyography (EMG) from the SCM and SC was recorded, and the onset time and the average rectified value of the EMG signal was determined for epochs of 100 ms; starting 100 ms prior to and 500 ms after the perturbation onset. Individuals with NP, as compared to HC, demonstrated delayed onset times and reduced EMG amplitude of the SCM and SC muscles in response to all postural perturbations. Such findings were most pronounced following the FS postural perturbation (healthy vs. NP for SCM 83.3 ± 8.0 vs. 86.3 ± 4.4 and SC 75.6 ± 3.5 vs. 89.3 ± 4.2), which was also associated with the greatest change (expressed in % relative to baseline) in EMG amplitude (healthy vs. NP for SCM 206.6 ± 50.4 vs. 115.9 ± 15.7 and SC 83.4 ± 19.2 vs. 69.2 ± 10.9) across all postural perturbations types. Individuals with NP display altered neural control of the neck musculature in response to rapid, unanticipated full body postural perturbations. Although the relative timing of neck musculature activity in individuals with NP appears to be intact, simultaneous co-activation of the neck musculature emerges for unanticipated anterior-posterior postural perturbations. PMID:24632836

  9. Gravity wave activities in the stratosphere and mesosphere during sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Li, Tao; Leblanc, Thierry; McDermid, I. Stuart; Riggin, Dennis; Fritts, Dave C.

    The gravity wave activities in the stratosphere and mesosphere of subtropics during the sudden stratospheric warming were studied using the temperature profiles measured by the Jet Propul-sion Laboratory (JPL) Rayleigh lidar at Mauna Loa Observatory (19.5N, 195.6W), Hawaii, and horizontal wind profiles measured by the MF radar at Kauai (22N, 200.2W), Hawaii. We found that the significant enhancement of gravity wave activities was observed before the sudden stratospheric warming in winter 2005/2006, followed by the decrease of activity during and after the warming. The significant change of GW activities during the warming will be dis-cussed together with the ECMWF wind in the stratosphere and MF radar mean wind in the mesosphere.

  10. Ionospheric reaction on sudden stratospheric warming events in Russiás Asia region

    NASA Astrophysics Data System (ADS)

    Polyakova, Anna; Perevalova, Natalya; Chernigovskaya, Marina

    2015-12-01

    The response of the ionosphere to sudden stratospheric warmings (SSWs) in the Asian region of Russia is studied. Two SSW events observed in 2008-2009 and 2012-2013 winter periods of extreme solar minimum and moderate solar maximum are considered. To detect the ionospheric effects caused by SSWs, we carried out a joint analysis of global ionospheric maps (GIM) of the total electron content (TEC), MLS (Microwave Limb Sounder, EOS Aura) measurements of temperature vertical profiles, as well as NCEP/NCAR and UKMO Reanalysis data. For the first time, it was found that during strong SSWs, in the mid-latitude ionosphere the amplitude of diurnal TEC variation decreases nearly half compared to quiet days. At the same time, the intensity of TEC deviations from the background level increases. It was also found that at SSW peak the midday TEC maximum decreases, and night/morning TEC values increase compared to quiet days. It was shown that during SSWs, TEC dynamics was identical for different geophysical conditions.The response of the ionosphere to sudden stratospheric warmings (SSWs) in the Asian region of Russia is studied. Two SSW events observed in 2008-2009 and 2012-2013 winter periods of extreme solar minimum and moderate solar maximum are considered. To detect the ionospheric effects caused by SSWs, we carried out a joint analysis of global ionospheric maps (GIM) of the total electron content (TEC), MLS (Microwave Limb Sounder, EOS Aura) measurements of temperature vertical profiles, as well as NCEP/NCAR and UKMO Reanalysis data. For the first time, it was found that during strong SSWs, in the mid-latitude ionosphere the amplitude of diurnal TEC variation decreases nearly half compared to quiet days. At the same time, the intensity of TEC deviations from the background level increases. It was also found that at SSW peak the midday TEC maximum decreases, and night/morning TEC values increase compared to quiet days. It was shown that during SSWs, TEC dynamics was

  11. Group planarian sudden mortality: Is the threshold around global geomagnetic activity ≥K6?

    PubMed Central

    Murugan, Nirosha J; Karbowski, Lukasz M; Mekers, William Ft; Persinger, Michael A

    2015-01-01

    Sudden deaths in groups of animals have been observed by field and laboratory biologists. We have measured mortalities in large group-housed planarian during the infrequent periods of very intense geomagnetic activity. In 13 separate episodes over the last 5 y we have observed the sudden death in our laboratory of hundreds of planarian if their density was about 1 worm per cc and the global geomagnetic activity was K≥6 the day before or the day of the observation of the mortality. Such mortality never occurred in other conditions or days. Both estimates of the "magnetic moment" of a planarian in magnetic fields above this threshold of sustained magnetic flux density as well as the magnetic energy within the planarian volume predict values that could affect phenomenon associated with the total numbers of pH-dependent charges within each worm. These conditions could affect the Levin-Burr bioelectrical signals and networks that affect patterning information and sustainability in whole living systems. The establishment of a central reservoir for the report of these transient events might allow Life Scientists to more fully appreciate the impact of these pervasive global stimuli upon dense groups of animals. PMID:27066174

  12. Usefulness of 10 genomic regions in soybean associated with sudden death syndrome resistance.

    PubMed

    Luckew, A S; Leandro, L F; Bhattacharyya, M K; Nordman, D J; Lightfoot, D A; Cianzio, S R

    2013-09-01

    Sudden death syndrome (SDS) is an important soybean [Glycine max (L) Merrill] disease caused by the soilborne fungus Fusarium virguliforme. Currently, 14 quantitative trait loci (QTL) had been confirmed associated with resistance or tolerance to SDS. The objective of the study was to evaluate usefulness of 10 of these QTL in controlling disease expression. Six populations were developed providing a total of 321 F2-derived lines for the study. Recombinant inbred lines (RIL) used as parents were obtained from populations of 'Essex' × 'Forrest' (EF), 'Flyer' × 'Hartwig' (FH), and 'Pyramid' × 'Douglas' (PD). Disease resistance was evaluated in the greenhouse at three different planting times, each with four replications, using sorghum infested with F. virguliforme homogeneously mixed in the soil (Luckew et al., Crop Sci 52:2215-2223, 2012). Four disease assessment criteria-foliar disease incidence (DI), foliar leaf scorch disease severity (DS), area under the disease progress curve (AUDPC), and root rot severity-were used. QTL were identified in more than one of the disease assessment criteria, mainly associated with lines in the most resistant categories. Five QTL (qRfs4, qRfs5, qRfs7, qRfs12, and Rfs16) were associated with at least one of the disease assessments across multiple populations. Of the five, qRfs4 was associated with DI, AUDPC, and root rot severity, and Rfs16 with AUDPC and root rot severity. The findings suggest it may be possible for plant breeders to focus on stacking a subset of the previously identified QTL to improve resistance to SDS in soybean. PMID:23793550

  13. Total Electron Content (TEC) disturbances over Brazilian region during the minor sudden stratospheric warming (SSW 2012) event of January 2012

    NASA Astrophysics Data System (ADS)

    Vieira, Francisco; Fagundes, Paulo Roberto; Kavutarapu, Venkatesh; Gil Pillat, Valdir

    2016-07-01

    The effects of Sudden Stratospheric Warming on ionosphere have been investigated by several scientists, using different observational techniques and model simulations. However, the 2011-2012 minor event is one of those that are less studied. Since, the zonal westward wind is slowed without reversing to eastward, this SSW was consider as a minor event. The stratospheric temperature started increasing on December 26, 2011, reached its peak on January 18, 2012, and afterwards started decreasing slowly. In addition, there was moderate geomagnetic storm on January 22-25, 2012, after the SSW temperature peak. In the present study, the GPS-TEC measurements from a network of 72 receivers over the Brazilian region are considered. This network of 72 GPS-TEC locations lies between 5 N and 30 S (35 degrees) latitudes and 35 W and 65 W (30 degrees) longitudes. Further, two chains of GPS receivers are used to study the response of Equatorial Ionization Anomaly (EIA) changes in the Brazilian East and West sectors, as well as its day-to-day variability before and during the SSW2012. It was noted that the TEC is depleted to the order of 30% all over the Brazilian region, from equator to beyond the EIA regions and from East to West sectors. It is also noticed that the EIA strengths at East and West sectors were suppressed after the stratospheric temperature peak. However, the Brazilian West sector was found to be more disturbed compared to the East sector during this SSW event.

  14. Genomic analysis of a region encompassing QRfs1 and QRfs2: genes that underlie soybean resistance to sudden death syndrome.

    PubMed

    Triwitayakorn, K; Njiti, V N; Iqbal, M J; Yaegashi, S; Town, C; Lightfoot, D A

    2005-02-01

    Candidate genes were identified for two loci, QRfs2 providing resistance to the leaf scorch called soybean (Glycine max (L.) Merr.) sudden death syndrome (SDS) and QRfs1 providing resistance to root infection by the causal pathogen Fusarium solani f.sp. glycines. The 7.5 +/- 0.5 cM region of chromosome 18 (linkage group G) was shown to encompass a cluster of resistance loci using recombination events from 4 near-isogenic line populations and 9 DNA markers. The DNA markers anchored 9 physical map contigs (7 are shown on the soybean Gbrowse, 2 are unpublished), 45 BAC end sequences (41 in Gbrowse), and contiguous DNA sequences of 315, 127, and 110 kbp. Gene density was high at 1 gene per 7 kbp only around the already sequenced regions. Three to 4 gene-rich islands were inferred to be distributed across the entire 7.5 cM or 3.5 Mbp showing that genes are clustered in the soybean genome. Candidate resistance genes were identified and a molecular basis for interactions among the disease resistance genes in the cluster inferred. PMID:15729404

  15. Active region seismology

    NASA Technical Reports Server (NTRS)

    Bogdan, Tom; Braun, D. C.

    1995-01-01

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

  16. Active region coronal evolution

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  17. Muscle activation characteristics of the front leg during baseball swings with timing correction for sudden velocity decrease.

    PubMed

    Ohta, Yoichi; Nakamoto, Hiroki; Ishii, Yasumitsu; Ikudome, Sachi; Takahashi, Kyohei; Shima, Norihiro

    2014-01-01

    This study aimed to clarify the activation characteristics of the vastus lateralis muscle in the front leg during timing correction for a sudden decrease in the velocity of a target during baseball swings. Eleven male collegiate baseball players performed coincident timing tasks that comprised constant velocity of 8 m/s (unchanged) and a sudden decrease in velocity from 8 to 4 m/s (decreased velocity). Electromyography (EMG) revealed that the muscle activation was typically monophasic when responding unchanged conditions. The type of muscle activation during swings in response to decreased velocity condition was both monophasic and biphasic. When biphasic activation appeared in response to decreased velocity, the impact time and the time to peak EMG amplitude were significantly prolonged and the timing error was significantly smaller than that of monophasic activation. However, the EMG onset from the target start was consistent both monophasic and biphasic activation in response to conditions of decreased velocity. In addition, batters with small timing errors in response to decreased velocity were more likely to generate biphasic EMG activation. These findings indicated that timing correction for a sudden decrease in the velocity of an oncoming target is achieved by modifying the muscle activation characteristics of the vastus lateralis muscle of front leg from monophasic to biphasic to delay reaching peak muscle activation and thus prolong impact time. Therefore, the present findings suggests that the extent of timing errors in response to decreased velocity is influenced by the ability to correct muscle activation after its initiation rather than by delaying the initiation timing of muscle activation during baseball swings. PMID:25918848

  18. Muscle Activation Characteristics of the Front Leg During Baseball Swings with Timing Correction for Sudden Velocity Decrease

    PubMed Central

    Ohta, Yoichi; Nakamoto, Hiroki; Ishii, Yasumitsu; Ikudome, Sachi; Takahashi, Kyohei; Shima, Norihiro

    2015-01-01

    This study aimed to clarify the activation characteristics of the vastus lateralis muscle in the front leg during timing correction for a sudden decrease in the velocity of a target during baseball swings. Eleven male collegiate baseball players performed coincident timing tasks that comprised constant velocity of 8 m/s (unchanged) and a sudden decrease in velocity from 8 to 4 m/s (decreased velocity). Electromyography (EMG) revealed that the muscle activation was typically monophasic when responding unchanged conditions. The type of muscle activation during swings in response to decreased velocity condition was both monophasic and biphasic. When biphasic activation appeared in response to decreased velocity, the impact time and the time to peak EMG amplitude were significantly prolonged and the timing error was significantly smaller than that of monophasic activation. However, the EMG onset from the target start was consistent both monophasic and biphasic activation in response to conditions of decreased velocity. In addition, batters with small timing errors in response to decreased velocity were more likely to generate biphasic EMG activation. These findings indicated that timing correction for a sudden decrease in the velocity of an oncoming target is achieved by modifying the muscle activation characteristics of the vastus lateralis muscle of front leg from monophasic to biphasic to delay reaching peak muscle activation and thus prolong impact time. Therefore, the present findings suggests that the extent of timing errors in response to decreased velocity is influenced by the ability to correct muscle activation after its initiation rather than by delaying the initiation timing of muscle activation during baseball swings. PMID:25918848

  19. Gravity wave activity during stratospheric sudden warmings in the 2007-2008 Northern Hemisphere winter

    NASA Astrophysics Data System (ADS)

    Wang, Ling; Alexander, M. Joan

    2009-09-01

    We use temperature retrievals from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC)/Formosa Satellite Mission 3 (FORMOSAT-3) and Challenging Minisatellite Payload (CHAMP) Global Positioning Satellite (GPS) radio occultation profiles and independent temperature retrievals from the EOS satellite High Resolution Dynamics Limb Sounder (HIRDLS) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) aboard the TIMED satellite to investigate stratospheric sudden warming (SSW) events and the accompanying gravity wave (GW) temperature amplitudes in the 2007-2008 Northern Hemisphere winter. We identify four SSW events (including a major one) occurring from late January to late February in 2008. We detect enhanced GW amplitudes in the stratosphere and subdued GW amplitudes in the lower mesosphere during the warming events. The timing of GW enhancement/suppression and warming/cooling events was generally close (within a couple days). We also find that stratospheric GW amplitudes were generally larger at the polar vortex edge and smaller in the vortex core and outside of the vortex and that stratospheric GW amplitudes were generally small over the North Pacific. Using a simplified GW dispersion relation and a GW ray-tracing experiment, we demonstrate that the enhanced GW amplitudes in the stratosphere during SSWs could be explained largely by GW propagation considerations. The existence of GW critical levels (the level at which the background wind is the same as the GW phase speed) near the stratopause during SSWs would block propagation of GWs into the mesosphere and thus could lead to the observed subdued GW activity in the lower mesosphere. Since this is the first study to analyze the COSMIC and CHAMP GPS temperature retrievals up to 60 km in altitude, we compare the GPS analysis with those from HIRDLS and SABER measurements. We find that the temporal variability of zonal mean temperatures derived from the GPS data is

  20. Evolution of Active Regions

    NASA Astrophysics Data System (ADS)

    van Driel-Gesztelyi, Lidia; Green, Lucie May

    2015-09-01

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

  1. Sudden death in epileptic rats exposed to nocturnal magnetic fields that simulate the shape and the intensity of sudden changes in geomagnetic activity: an experiment in response to Schnabel, Beblo and May

    NASA Astrophysics Data System (ADS)

    Persinger, M. A.; McKay, B. E.; O'Donovan, C. A.; Koren, S. A.

    2005-03-01

    To test the hypothesis that sudden unexplained death (SUD) in some epileptic patients is related to geomagnetic activity we exposed rats in which limbic epilepsy had been induced to experimentally produced magnetic fields designed to simulate sudden storm commencements (SSCs). Prior studies with rats had shown that sudden death in groups of rats in which epilepsy had been induced months earlier was associated with the occurrence of SSCs and increased geomagnetic activity during the previous night. Schnabel et al. [(2000) Neurology 54:903 908) found no relationship between SUD in human patients and geomagnetic activity. A total of 96 rats were exposed to either 500, 50, 10 40 nT or sham (less than 10 nT) magnetic fields for 6 min every hour between midnight and 0800 hours (local time) for three successive nights. The shape of the complex, amplitude-modulated magnetic fields simulated the shape and structure of an average SSC. The rats were then seized with lithium and pilocarpine and the mortality was monitored. Whereas 10% of the rats that had been exposed to the sham field died within 24 h, 60% of the rats that had been exposed to the experimental magnetic fields simulating natural geomagnetic activity died (P<.001) during this period. These results suggest that correlational analyses between SUD in epileptic patients and increased geomagnetic activity can be simulated experimentally in epileptic rats and that potential mechanisms might be testable directly.

  2. Decreased argyrophilic nucleolar organiser region (AgNOR) expression in Purkinje cells: first signal of neuronal damage in sudden fetal and infant death

    PubMed Central

    Lavezzi, Anna M; Alfonsi, Graziella; Pusiol, Teresa; Matturri, Luigi

    2016-01-01

    Aims The nucleolus is an important cellular component involved in the biogenesis of the ribosome. This study was performed in order to validate the introduction of the argyrophilic nucleolar organiser region (AgNOR) stain technique, specific for the nucleoli detection, in neuropathological studies on sudden fetal and infant death. Methods In a wide set of fetuses and infants, aged from 27 gestational weeks to eight postnatal months and dead from both known and unknown causes, an in-depth neuropathological study usually applied at the Lino Rossi Research Center of the Milan University was implemented by the AgNOR method. Results Peculiar abnormalities of the nucleoli, as partial or total disruption above all in Purkinje cells (PCs), were exclusively found in victims of sudden fetal and infant death, and not in controls. The observed nucleolar alterations were frequently related to nicotine absorption in pregnancy. Conclusions We conclude that these findings represent early hallmarks of PC degeneration, contributing to the pathophysiology of sudden perinatal death. PMID:26567317

  3. Satellite observations of gravity wave activity and dissipation during sudden stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Ern, Manfred; Preusse, Peter; Riese, Martin

    2015-04-01

    Sudden stratospheric warmings (SSWs) are a circulation anomaly that occurs mainly at high northern latitudes in boreal winter. During major SSWs the eastward directed polar jet reverses, and, for a certain period, the stratosphere is governed by anomalous westward winds. It is known that both planetary waves and gravity waves contribute to the formation and evolution of SSWs. However, the small horizontal scales of gravity waves (tens to a few thousand km) challenge both observations and modeling of gravity waves. Therefore, the role of gravity waves during SSWs is still not fully understood. In particular, gravity waves should play an important role during the recovery of the stratopause and of the eastward directed polar jet after major SSWs. This is indicated by several modeling efforts. However, validation by global observations of gravity waves is still an open issue. Gravity wave momentum fluxes and potential gravity wave drag were derived from HIRDLS and SABER satellite observations, and the role of gravity waves during recent SSWs in the boreal winters 2001/2002-2013/2014 is investigated. We find that gravity waves with slow horizontal phase speeds, likely mountain waves, play an important role during SSWs. Both gravity wave momentum fluxes and gravity wave drag are enhanced before the central date of major SSWs. After the central date, gravity wave momentum fluxes and gravity wave drag in the stratosphere are strongly reduced. Still, gravity wave drag contributes to the wind reversals related to the anomalous westward winds. Another finding is that, after major SSWs, the contribution of gravity wave drag at the bottom of re-established eastward directed polar jets is small. At the top of those jets, however, strong gravity wave drag is found, which indicates that gravity waves contribute to the downward propagation of newly formed polar jets and of elevated stratopauses to their "climatological" altitude. This confirms recent modeling work by, for example

  4. Regional Activities Division. Papers.

    ERIC Educational Resources Information Center

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

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

  5. Sudden event recognition: a survey.

    PubMed

    Suriani, Nor Surayahani; Hussain, Aini; Zulkifley, Mohd Asyraf

    2013-01-01

    Event recognition is one of the most active research areas in video surveillance fields. Advancement in event recognition systems mainly aims to provide convenience, safety and an efficient lifestyle for humanity. A precise, accurate and robust approach is necessary to enable event recognition systems to respond to sudden changes in various uncontrolled environments, such as the case of an emergency, physical threat and a fire or bomb alert. The performance of sudden event recognition systems depends heavily on the accuracy of low level processing, like detection, recognition, tracking and machine learning algorithms. This survey aims to detect and characterize a sudden event, which is a subset of an abnormal event in several video surveillance applications. This paper discusses the following in detail: (1) the importance of a sudden event over a general anomalous event; (2) frameworks used in sudden event recognition; (3) the requirements and comparative studies of a sudden event recognition system and (4) various decision-making approaches for sudden event recognition. The advantages and drawbacks of using 3D images from multiple cameras for real-time application are also discussed. The paper concludes with suggestions for future research directions in sudden event recognition. PMID:23921828

  6. Sudden Event Recognition: A Survey

    PubMed Central

    Suriani, Nor Surayahani; Hussain, Aini; Zulkifley, Mohd Asyraf

    2013-01-01

    Event recognition is one of the most active research areas in video surveillance fields. Advancement in event recognition systems mainly aims to provide convenience, safety and an efficient lifestyle for humanity. A precise, accurate and robust approach is necessary to enable event recognition systems to respond to sudden changes in various uncontrolled environments, such as the case of an emergency, physical threat and a fire or bomb alert. The performance of sudden event recognition systems depends heavily on the accuracy of low level processing, like detection, recognition, tracking and machine learning algorithms. This survey aims to detect and characterize a sudden event, which is a subset of an abnormal event in several video surveillance applications. This paper discusses the following in detail: (1) the importance of a sudden event over a general anomalous event; (2) frameworks used in sudden event recognition; (3) the requirements and comparative studies of a sudden event recognition system and (4) various decision-making approaches for sudden event recognition. The advantages and drawbacks of using 3D images from multiple cameras for real-time application are also discussed. The paper concludes with suggestions for future research directions in sudden event recognition. PMID:23921828

  7. Active Region Release Two CMEs

    NASA Video Gallery

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

  8. [Early Detection of Iliac Artery Rupture by Sudden Steep Reduction of Regional Saturation of Oxygen at the Ipsilateral Foot during Transcatheter Aortic Valve Implantation--A Case Report].

    PubMed

    Saito, Shun; Ishii, Hisanari

    2016-02-01

    An 80-year-old woman with severe aortic stenosis was planned to undergo transcatheter aortic valve implantation (TAVI) under general anesthesia. Due to severe stenosis of the femoral arteries, the left iliac artery was cut down and a 16 F Edwards SAPIEN Expandable Sheath (eSheath : Edwards Lifesciences, Irvine, CA) was inserted into the artery smoothly. After balloon aortic valvuloplasty (BAV), an artificial valve was tried to deploy but stuck in the middle of eSheath. Suddenly regional saturation of oxygen (rSO2) at the ipsilateral foot decreased steeply without other significant hemodynamic instabilities. At insertion site of eSheath, the left external iliac artery rupture occurred. To our surprise, there was almost no major bleeding because of the artery spasm and suppression of the large bore sheath. eSheath and the stuck valve were taken out together and TAVI was discontinued. The artery was replaced with a graft, and rSO2 of the foot recovered. Her aortic stenosis improved to moderate by balloon aortic valvuloplasty (BAV) according to transthoracic echocardiography. The patient was discharged on foot without complications. To our knowledge, this is a first report of a silent rupture of the iliac artery during TAVI to be detected by sudden decrease of the foot rSO2 and treated with no fatal events. PMID:27017778

  9. Simulated sudden increase in geomagnetic activity and its effect on heart rate variability: Experimental verification of correlation studies

    NASA Astrophysics Data System (ADS)

    Caswell, Joseph M.; Singh, Manraj; Persinger, Michael A.

    2016-08-01

    Previous research investigating the potential influence of geomagnetic factors on human cardiovascular state has tended to converge upon similar inferences although the results remain relatively controversial. Furthermore, previous findings have remained essentially correlational without accompanying experimental verification. An exception to this was noted for human brain activity in a previous study employing experimental simulation of sudden geomagnetic impulses in order to assess correlational results that had demonstrated a relationship between geomagnetic perturbations and neuroelectrical parameters. The present study employed the same equipment in a similar procedure in order to validate previous findings of a geomagnetic-cardiovascular dynamic with electrocardiography and heart rate variability measures. Results indicated that potential magnetic field effects on frequency components of heart rate variability tended to overlap with previous correlational studies where low frequency power and the ratio between low and high frequency components of heart rate variability appeared affected. In the present study, a significant increase in these particular parameters was noted during geomagnetic simulation compared to baseline recordings.

  10. Multithermal emission in active regions

    NASA Astrophysics Data System (ADS)

    Del Zanna, Giulio

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

  11. Prenatal nicotine-exposure alters fetal autonomic activity and medullary neurotransmitter receptors: implications for sudden infant death syndrome.

    PubMed

    Duncan, Jhodie R; Garland, Marianne; Myers, Michael M; Fifer, William P; Yang, May; Kinney, Hannah C; Stark, Raymond I

    2009-11-01

    During pregnancy, exposure to nicotine and other compounds in cigarette smoke increases the risk of the sudden infant death syndrome (SIDS) two- to fivefold. Serotonergic (5-HT) abnormalities are found, in infants who die of SIDS, in regions of the medulla oblongata known to modulate cardiorespiratory function. Using a baboon model, we tested the hypothesis that prenatal exposure to nicotine alters 5-HT receptor and/or transporter binding in the fetal medullary 5-HT system in association with cardiorespiratory dysfunction. At 87 (mean) days gestation (dg), mothers were continuously infused with saline (n = 5) or nicotine (n = 5) at 0.5 mg/h. Fetuses were surgically instrumented at 129 dg for cardiorespiratory monitoring. Cesarean section delivery and retrieval of fetal medulla were performed at 161 (mean) dg for autoradiographic analyses of nicotinic and 5-HT receptor and transporter binding. In nicotine-exposed fetuses, high-frequency heart rate variability was increased 55%, possibly reflecting increases in the parasympathetic control of heart rate. This effect was more pronounced with greater levels of fetal breathing and age. These changes in heart rate variability were associated with increased 5-HT(1A) receptor binding in the raphé obscurus (P = 0.04) and increased nicotinic receptor binding in the raphé obscurus and vagal complex (P < 0.05) in the nicotine-exposed animals compared with controls (n = 6). The shift in autonomic balance in the fetal primate toward parasympathetic predominance with chronic exposure to nicotine may be related, in part, to abnormal 5-HT-nicotine alterations in the raphé obscurus. Thus increased risk for SIDS due to maternal smoking may be partly related to the effects of nicotine on 5-HT and/or nicotinic receptors. PMID:19729586

  12. SDO Sees Active Region Outbursts

    NASA Video Gallery

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

  13. Vision Loss, Sudden

    MedlinePlus

    ... of age-related macular degeneration. Spotlight on Aging: Vision Loss in Older People Most commonly, vision loss ... Some Causes and Features of Sudden Loss of Vision Cause Common Features* Tests Sudden loss of vision ...

  14. Sudden Infant Death Syndrome

    MedlinePlus

    Sudden infant death syndrome (SIDS) is the sudden, unexplained death of an infant younger than one year old. Some people call ... boys, African Americans, and American Indian/Alaska Native infants have a higher risk of SIDS. Although health ...

  15. Sudden Infant Death Syndrome

    MedlinePlus

    Sudden infant death syndrome (SIDS) is the sudden, unexplained death of an infant younger than one year old. Some people call SIDS "crib death" because many babies who die of SIDS are found in their ...

  16. Sudden Cardiac Arrest

    MedlinePlus

    ... from American Heart Association Aneurysms and Dissections Angina Arrhythmia Bundle Branch Block Cardiomyopathy Carotid Artery Disease Chronic ... terms: SCA, sudden cardiac death (SCD), sudden death, arrhythmias, ... ventricular fibrillation, defibrillator, automatic cardiac defibrillator ( ...

  17. Ligninolytic Activity of Fusarium virguliforme (SYN. F. solani f. sp. glycines), the Causal Agent of Soybean Sudden Death Syndrome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium virguliforme (syn. F. solani f. sp. glycines), a soil-borne fungus, is the causal agent of soybean sudden death syndrome (SDS), one of the most important diseases of soybean. Lignin degradation is not common in most soilborne fungi which are considered to be cellulose degraders only. In thi...

  18. Global oscillations and active regions

    NASA Astrophysics Data System (ADS)

    Durrant, C. J.

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

  19. [The Sudden Infant Death Syndrome.

    ERIC Educational Resources Information Center

    Florida's Health, 1976

    1976-01-01

    This collection of articles on the Sudden Infant Death Syndrome (SIDS), drawn from a southeastern regional symposium on the subject, summarizes much of what is known about the occurrence of SIDS, including current information about its causes. The background of state action in Florida is reviewed, with emphasis on the need for increased public and…

  20. Degree Of Diminution In Vagal-Cardiac Activity Predicts Sudden Death In Familial Dysautonomia When Resting Tachycardia Is Absent

    NASA Technical Reports Server (NTRS)

    Schlegel, T. T.; Marthol, H.; Bucchner, S.; Tutaj, M.; Berlin, D.; Axelrod, F. B.; Hilz, M. J.

    2004-01-01

    Patients with familial dysautonomia (FD) have an increased risk of sudden death, but sensitive and specific predictors of sudden death in FD are lacking. Methods. We recorded 10-min resting high-fidelity 12-lead ECGs in 14 FD patients and in 14 age/gender-matched healthy subjects and studied 25+ different heart rate variability (HRV) indices for their ability to predict sudden death in the FD patients. Indices studied included those from 4 "nonlinear" HRV techniques (detrended fluctuation analysis, approximate entropy, correlation dimension, and PoincarC analyses). The predictive value of PR, QRS, QTc and JTc intervals, QT dispersion (QTd), beat-to-beat QT and PR interval variability indices (QTVI and PRVI) and 12- lead high frequency QRS ECG (150-250 Hz) were also studied. FD patients and controls (C) differed (Pless than 0.0l) with respect to 20+ of the HRV indices (FD less than C) and with respect to QTVI and PRVI (FDBC) and HF QRS- related root mean squared voltages (FDBC) and reduced amplitude zone counts (FD less than C). They differed less with respect to PR intervals (FD less than C) and JTc intervals (FD greater than C) (P less than 0.05 for both) and did not differ at all with respect to QRS and QTc intervals and to QTd. Within 12 months after study, 2 of the 14 patients succumbed to sudden cardiac arrest. The best predictor of sudden death was the degree of diminution in HRV vagal-cardiac (parasympathetic) parameters such as RMSSD, the SDl of Poincare plots, and HF spectral power. Excluding the two FD patients who had resting tachycardia (HR greater than 100, which confounds traditional HRV analyses), the following criteria were independently 100% sensitive and 100% specific for predicting sudden death in the remaining 12 FD patients during spontaneous breathing: RMSSD less than 13 ms and/or PoincarC SD1 less than 9 ms. In FD patients without supine tachycardia, the degree of diminution in parasympathetic HRV parameters (by high-fidelity ECG) predicts

  1. Repeated mass strandings of Miocene marine mammals from Atacama Region of Chile point to sudden death at sea.

    PubMed

    Pyenson, Nicholas D; Gutstein, Carolina S; Parham, James F; Le Roux, Jacobus P; Chavarría, Catalina Carreño; Little, Holly; Metallo, Adam; Rossi, Vincent; Valenzuela-Toro, Ana M; Velez-Juarbe, Jorge; Santelli, Cara M; Rogers, David Rubilar; Cozzuol, Mario A; Suárez, Mario E

    2014-04-22

    Marine mammal mass strandings have occurred for millions of years, but their origins defy singular explanations. Beyond human causes, mass strandings have been attributed to herding behaviour, large-scale oceanographic fronts and harmful algal blooms (HABs). Because algal toxins cause organ failure in marine mammals, HABs are the most common mass stranding agent with broad geographical and widespread taxonomic impact. Toxin-mediated mortalities in marine food webs have the potential to occur over geological timescales, but direct evidence for their antiquity has been lacking. Here, we describe an unusually dense accumulation of fossil marine vertebrates from Cerro Ballena, a Late Miocene locality in Atacama Region of Chile, preserving over 40 skeletons of rorqual whales, sperm whales, seals, aquatic sloths, walrus-whales and predatory bony fish. Marine mammal skeletons are distributed in four discrete horizons at the site, representing a recurring accumulation mechanism. Taphonomic analysis points to strong spatial focusing with a rapid death mechanism at sea, before being buried on a barrier-protected supratidal flat. In modern settings, HABs are the only known natural cause for such repeated, multispecies accumulations. This proposed agent suggests that upwelling zones elsewhere in the world should preserve fossil marine vertebrate accumulations in similar modes and densities. PMID:24573855

  2. Repeated mass strandings of Miocene marine mammals from Atacama Region of Chile point to sudden death at sea

    PubMed Central

    Pyenson, Nicholas D.; Gutstein, Carolina S.; Parham, James F.; Le Roux, Jacobus P.; Chavarría, Catalina Carreño; Little, Holly; Metallo, Adam; Rossi, Vincent; Valenzuela-Toro, Ana M.; Velez-Juarbe, Jorge; Santelli, Cara M.; Rogers, David Rubilar; Cozzuol, Mario A.; Suárez, Mario E.

    2014-01-01

    Marine mammal mass strandings have occurred for millions of years, but their origins defy singular explanations. Beyond human causes, mass strandings have been attributed to herding behaviour, large-scale oceanographic fronts and harmful algal blooms (HABs). Because algal toxins cause organ failure in marine mammals, HABs are the most common mass stranding agent with broad geographical and widespread taxonomic impact. Toxin-mediated mortalities in marine food webs have the potential to occur over geological timescales, but direct evidence for their antiquity has been lacking. Here, we describe an unusually dense accumulation of fossil marine vertebrates from Cerro Ballena, a Late Miocene locality in Atacama Region of Chile, preserving over 40 skeletons of rorqual whales, sperm whales, seals, aquatic sloths, walrus-whales and predatory bony fish. Marine mammal skeletons are distributed in four discrete horizons at the site, representing a recurring accumulation mechanism. Taphonomic analysis points to strong spatial focusing with a rapid death mechanism at sea, before being buried on a barrier-protected supratidal flat. In modern settings, HABs are the only known natural cause for such repeated, multispecies accumulations. This proposed agent suggests that upwelling zones elsewhere in the world should preserve fossil marine vertebrate accumulations in similar modes and densities. PMID:24573855

  3. Cometary nucleus and active regions

    NASA Technical Reports Server (NTRS)

    Whipple, F. L.

    1984-01-01

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

  4. Analysis of Stratospheric Sudden Warming (SSW) over Tropical and Sub-tropical Regions of India using Rayleigh Lidar and Satellite measurements

    NASA Astrophysics Data System (ADS)

    Sharma, Som Kumar; Chandra, Harish; Jayaraman, Achuthan; Gadhavi, Harish; Vaishnav, Rajesh

    2016-07-01

    The Stratospheric Sudden Warming (SSW) is one of the most spectacular phenomena in the atmosphere and has impacts on the Earth's lower, middle and upper atmospheres. Lidar is one of the best instrument to study Earth's middle atmospheric thermal structure with very temporal and vertical resolution. A Nd: YAG laser based Rayleigh Lidar is operational over Mt. Abu India (24.5 oN, 72.7 oE) since 1997.In this study, two major SSW episodes associated with vortex displacement and vortex splitting occurred in year 1998 and 1999 respectively are investigated first time over Mt. Abu using lidar observations. Analyses show that CIRA-86 and MSISE-90 model fail to capture these SSW episode, whereas ground based lidar and satellite observations from Halogen occultation experiment (HALOE) onboard upper atmospheric research satellite (UARS)are able to capture effect of SSW events. Lidar measurements are able to capture SSW warming and its decay very accurately. Impact of SSW is further investigated in ECMWF Interim reanalyzed potential vorticity. Moreover, a detail study has been presented to understand the latitudinal variation of SSW warming and associated mesospheric cooling over Indian region.

  5. Sudden Cardiac Death

    PubMed Central

    Weinberg, Marc

    1978-01-01

    Over the past decade, there has been a significant decrease in the hospital mortality of patients with coronary artery disease. However, sudden cardiac death, which accounts for the majority of deaths from coronary artery disease, hasbeen little affected. This report reviews the pathology, electrophysiology, demographics and clinical presentation of sudden cardiac death. Emergency care and possible preventative measures are examined. PMID:356435

  6. Sudden Infant Death Syndrome.

    ERIC Educational Resources Information Center

    Barnett, Henry L.; And Others

    There is a growing body of evidence that Sudden Infant Death Syndrome (SIDS) victims are not completely normal and healthy, as was once believed. A variety of new information from several disciplines strongly suggests that the infant who dies suddenly and unexpectedly may do so because of subtle developmental, neurologic, cardiorespiratory, and…

  7. Volcanically Active Regions on Io

    NASA Technical Reports Server (NTRS)

    1997-01-01

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

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

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

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

  8. Unusual sudden death.

    PubMed Central

    Warren, J. V.

    1985-01-01

    In contrast to usual sudden death seen in the course of coronary artery disease, individuals dying suddenly from other causes form a complex array of situations. In some the causes are readily identifiable. No simple pattern is available to identify the potential candidate, but on review of the many causes some moves by the physician may be helpful. For example, a more complete physical evaluation of young individuals participating in competitive athletics is in order. This is particularly true if the athlete reports an episode of unexplained syncope. This may well be the warning of a propensity towards sudden death under physical and emotional stress. Knowledge of the specific problems in underwater swimming and diving, in high altitude exposure and in various circumstances such as certain weight reduction diets and industrial exposures may lead to control of some types of unusual sudden death. Clearly, more studies are needed to give answers in so called crib death. As the incidence of usual sudden death falls, these unusual forms of sudden death will represent a more important fraction of sudden death in general. PMID:6537674

  9. Emerging flux in active regions. [of sun

    NASA Technical Reports Server (NTRS)

    Liggett, M.; Zirin, H.

    1985-01-01

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

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

    SciTech Connect

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

    2014-11-01

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

  11. Changes in cellular distribution regulate SKD1 ATPase activity in response to a sudden increase in environmental salinity in halophyte ice plant.

    PubMed

    Jou, Yingtzy; Chiang, Chih-Pin; Yen, Hungchen Emilie

    2013-01-01

    Halophyte Mesembryanthemum crystallinum L. (ice plant) rapidly responds to sudden increases in salinity in its environment by activating specific salt-tolerant mechanisms. One major strategy is to regulate a series of ion transporters and proton pumps to maintain cellular Na(+)/K(+) homeostasis. Plant SKD1 (suppressor of K(+) transport growth defect 1) proteins accumulate in cells actively engaged in the secretory processes, and play a critical role in intracellular protein trafficking. Ice plant SKD1 redistributes from the cytosol to the plasma membrane hours after salt stressed. In combination with present knowledge of this protein, we suggest that stress facilitates SKD1 movement to the plasma membrane where ADP/ATP exchange occurs, and functions in the regulation of membrane components such as ion transporters to avoid ion toxicity. PMID:24390077

  12. Geophysical variables and behavior: LXXXV. Sudden infant death, bands of geomagnetic activity, and pc1 (0.2 to 5 HZ) geomagnetic micropulsations.

    PubMed

    O'Connor, R P; Persinger, M A

    1999-04-01

    Pc1s (continuous pulsations) within the geomagnetic field, whose durations are about 30 minutes but which can reoccur several times nightly, are observed during periods when global geomagnetic activity is very low (less than 10 nT). The hypothesis that these 0.2 to 5 Hz synchronized micropulsations or hydromagnetic emissions might stimulate physical chemical cascades within the brain that precipitate the sudden death in infants was tested by correlational analysis for a two-year period (1960-1961) for Ontario. Results were consistent with the hypothesis that the monthly incidences of these unexpected deaths, pcl micropulsations and geomagnetic activity less than 10 nT displayed a shared source of variance. Implications are discussed. PMID:10483626

  13. Sudden Death Following Exercise; a Case Series

    PubMed Central

    Najari, Fares; Alimohammadi, Alimohammad; Ghodrati, Parisa

    2016-01-01

    Introduction: Natural and unexpected death that happens within less than one hour of first symptom occurrence is called sudden death. Cardiovascular diseases are the main known reason of sudden death and more than 75% of sudden deaths in athletes are assigned to it. Here we reported the autopsy results of all cases with sudden death following exercise that were referred to forensic center of Tehran, Iran, from 2009 to 2014. Methods: In this cross sectional study all subjects who were registered to forensic medicine center of Tehran, Iran, from 2009 to 2014, as a case of sudden death following exercise were evaluated. Demographic data and medical history as well as autopsy and toxicology findings were retrospectively gathered using profiles of the deceased. Results were reported using descriptive analysis. Results: 14 cases were registered as sudden death following exercise in forensic medicine profiles during the study period. Exploring the files of the mentioned deceased, revealed five non-compatible cases in this regard. Finally, 9 eligible cases were enrolled (88.9% male). The mean age of the deceased was 28.66 ± 10.86 years (range: 7 – 40). Toxicological tests were available for 7 cases, one of which was positive for tramadol. Sudden death following football was reported most frequently (44.4%). Only 3 (33.3%) cases had herald signs such as chest pain, syncope, or loss of consciousness. 1 case (11.11%) had a positive history of sudden death in relatives. Conclusion: Although most sudden death victims are asymptomatic until the event, all those who suffer from symptoms such as chest pain, shortness of breath, dizziness, fatigue and irregular heart rate during physical activities, should be screened regarding common probable causes of sudden death. PMID:27274521

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

    NASA Technical Reports Server (NTRS)

    Falconer, David; Moore, Ron

    2011-01-01

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

  15. The Twist Limit for Bipolar Active Regions

    NASA Technical Reports Server (NTRS)

    Moore, Ron; Falconer, David; Gary, Allen

    2008-01-01

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

  16. Sudden Death Syndrome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sudden death syndrome (SDS) is an important disease of soybean in North and South America. SDS first occurred in South America in the early 1990s. In the U.S.A., SDS was first detected in AK in 1971. Now SDS occurs in most soybean production areas of the U.S. The SDS pathogen is a soil-borne fungu...

  17. High resolution studies of complex solar active regions

    NASA Astrophysics Data System (ADS)

    Deng, Na

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

  18. Active Region Emergence and Remote Flares

    NASA Astrophysics Data System (ADS)

    Fu, Yixing; Welsch, Brian T.

    2016-02-01

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

  19. Hinode Captures Images of Solar Active Region

    NASA Video Gallery

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

  20. Sudden Infant Death Syndrome (SIDS)

    MedlinePlus

    ... Information Clinical Trials Resources and Publications Sudden Infant Death Syndrome (SIDS): Condition Information Skip sharing on social ... Share this: Page Content SIDS is the sudden death of an infant younger than 1 year of ...

  1. A review of vertical coupling in the Atmosphere-Ionosphere system: Effects of waves, sudden stratospheric warmings, space weather, and of solar activity

    NASA Astrophysics Data System (ADS)

    Yiğit, Erdal; Koucká Knížová, Petra; Georgieva, Katya; Ward, William

    2016-04-01

    This brief introductory review of some recent developments in atmosphere-ionosphere science is written for the "Vertical Coupling Special Issue" that is motivated by the 5th IAGA/ICMA/SCOSTEP Workshop on Vertical Coupling in the Atmosphere-Ionosphere System. Basic processes of vertical coupling in the atmosphere-ionosphere system are discussed, focusing on the effects of internal waves, such as gravity waves and solar tides, sudden stratospheric warmings (SSWs), and of solar activity on the structure of the atmosphere. Internal waves play a crucial role in the current state and evolution of the upper atmosphere-ionosphere system. SSW effects extend into the upper atmosphere, producing changes in the thermospheric circulation and ionospheric disturbances. Sun, the dominant energy source for the atmosphere, directly impacts the upper atmosphere and modulates wave-induced coupling. The emphasis is laid on the most recent developments in the field, while giving credits to older works where necessary. Various international activities in atmospheric vertical coupling, such as SCOSTEP's ROSMIC project, and a brief contextual discussion of the papers published in the special issue are presented.

  2. The flare productivity of active regions

    NASA Astrophysics Data System (ADS)

    Kuroda, N.; Christe, S.

    2012-12-01

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

  3. Is a sudden increase of irregularity of sunspot numbers a precursor of a return to low solar activity?

    NASA Astrophysics Data System (ADS)

    Shapoval, A.; Le Mouël, J.-L.; Courtillot, V.; Shnirman, M.

    2014-08-01

    We have recently introduced an irregularity index λ for daily sunspot numbers International Sunspot Number (ISSN), derived from the well-known Lyapunov exponent, that attempts to reflect irregularities in the chaotic process of solar activity. Like the Lyapunov exponent, the irregularity index is computed from the data for different embedding dimensions m (2-32). When m = 2, λ maxima match ISSN maxima of the Schwabe cycle, whereas when m = 3, λ maxima occur at ISSN minima. The patterns of λ as a function of time remain similar from m = 4 to 16: the dynamics of λ change between 1915 and 1935, separating two regimes, one from 1850 to 1915 and the other from 1935 to 2005, in which λ retains a similar structure. A sharp peak occurs at the time of the ISSN minimum between cycles 23 and 24, possibly a precursor of unusual cycle 24 and maybe a new regime change; λ is significantly smaller during the ascending and descending phases of solar cycles. Differences in values of the irregularity index observed for different cycles reflect differences in correlations in sunspot series at a scale much less than the 4 year sliding window used in computing them; the lifetime of sunspots provides a source of correlation at that time scale. The burst of short-term irregularity evidenced by the strong λ peak at the minimum of cycles 23 and 24 would reflect a decrease in correlation at the time scale of several days rather than a change in the shape of the cycle.

  4. Chromospheric Acoustic Oscillations in Active Flaring Regions

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  5. Growth and Decay of Solar Active Regions

    NASA Astrophysics Data System (ADS)

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

    2002-05-01

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

  6. The 17 GHz active region number

    SciTech Connect

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

    2014-08-01

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

  7. Magnesium and sudden death.

    PubMed

    Leary, W P; Reyes, A J

    1983-10-22

    Magnesium deficiency may result from reduced dietary intake of the ion or increased losses in sweat, urine or faeces. Stress potentiates magnesium deficiency, and an increased incidence of sudden death associated with ischaemic heart disease is found in some areas in which soil and drinking water lack magnesium. Furthermore, it has been demonstrated experimentally that reduction of the plasma magnesium level is associated with arterial spasm. Careful studies are required to assess the clinical importance of magnesium and the benefits of magnesium supplementation in man. PMID:6353622

  8. The Magnetic Free Energy in Active Regions

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  9. Fluxon Modeling of Active Region Evolution

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

  10. Quantifying the Complexity of Flaring Active Regions

    NASA Astrophysics Data System (ADS)

    Stark, B.; Hagyard, M. J.

    1997-05-01

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

  11. Quantifying the Complexity of Flaring Active Regions

    NASA Technical Reports Server (NTRS)

    Stark, B.; Hagyard, M. J.

    1997-01-01

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

  12. ON THE FORMATION OF ACTIVE REGIONS

    SciTech Connect

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

    2012-07-01

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

  13. On the Formation of Active Regions

    NASA Astrophysics Data System (ADS)

    Stein, Robert F.; Nordlund, Åke

    2012-07-01

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

  14. Fragmentation of suddenly heated liquids

    SciTech Connect

    Blink, J.A.

    1985-03-01

    Fragmentation of free liquids in Inertial Confinement Fusion reactors could determine the upper bound on reactor pulse rate. The x-ray ablated materials must cool and recondense to allow driver beam propagation. The increased surface area caused by fragmentation will enhance the cooling and condensation rates. Relaxation from the suddenly heated state will move a liquid into the negative pressure region under the liquid-vapor P-V dome. The lithium equation of state was used to demonstrate that neutron-induced vaporization uses only a minor fraction of the added heat, much less than would be required to drive the expansion. A 77% expansion of the lithium is required before the rapid vaporization process of spinodal decomposition could begin, and nucleation and growth are too slow to contribute to the expansion.

  15. Sudden infant death syndrome.

    PubMed

    Adams, Stephen M; Ward, Chad E; Garcia, Karla L

    2015-06-01

    Sudden infant death syndrome (SIDS) is the sudden unexpected death of a child younger than one year during sleep that cannot be explained after a postmortem evaluation including autopsy, a thorough history, and scene evaluation. The incidence of SIDS has decreased more than 50% in the past 20 years, largely as a result of the Back to Sleep campaign. The most important risk factors relate to the sleep environment. Prone and side sleeping positions are significantly more dangerous than the supine position. Bed sharing with a parent is strongly correlated with an increased risk of SIDS, especially in infants younger than 12 weeks. Apparent life-threatening events are not a risk factor for SIDS. Parents should place infants on their backs to sleep, should not share a bed, and should avoid exposing the infant to tobacco smoke. Other risk-reducing measures include using a firm crib mattress, breastfeeding, keeping vaccinations up to date, avoiding overheating due to overbundling, avoiding soft bedding, and considering the use of a pacifier during sleep once breastfeeding is established. One consequence of the Back to Sleep campaign is a significant increase in the incidence of occipital flattening. Infants who develop a flat spot should be placed with the head facing alternating directions each time he or she is put to bed. Supervised prone positioning while the infant is awake, avoiding excessive use of carriers, and upright positioning while awake are also recommended. PMID:26034855

  16. Solar Eruptions Initiated in Sigmoidal Active Regions

    NASA Astrophysics Data System (ADS)

    Savcheva, Antonia

    2016-07-01

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

  17. Asia Section. Regional Activities Division. Paper.

    ERIC Educational Resources Information Center

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

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

  18. Lipopolysaccharide Cross-Tolerance Delays Platelet-Activating Factor-Induced Sudden Death in Swiss Albino Mice: Involvement of Cyclooxygenase in Cross-Tolerance

    PubMed Central

    Jacob, Shancy Petsel; Lakshmikanth, Chikkamenahalli Lakshminarayana; Chaithra, Vyala Hanumanthareddy; Kumari, Titus Ruth Shantha; Chen, Chu-Huang; McIntyre, Thomas M.; Marathe, Gopal Kedihitlu

    2016-01-01

    Lipopolysaccharide (LPS) signaling through Toll-like receptor-4 (TLR-4) has been implicated in the pathogenesis of many infectious diseases. Some believe that TLR-mediated pathogenicity is due, in part, to the lipid pro-inflammatory mediator platelet-activating factor (PAF), but this has been questioned. To test the direct contribution of PAF in endotoxemia in murine models, we injected PAF intraperitoneally into Swiss albino mice in the presence and absence of LPS. PAF alone (5 μg/mouse) caused death within 15–20 min, but this could be prevented by pretreating mice with PAF-receptor (PAF-R) antagonists or PAF-acetylhydrolase (PAF-AH). A low dose of LPS (5 mg/kg body wt) did not impair PAF-induced death, whereas higher doses (10 or 20 mg/kg body wt) delayed death, probably via LPS cross-tolerance. Cross-tolerance occurred only when PAF was injected simultaneously with LPS or within 30 min of LPS injection. Tolerance does not appear to be due to an abundant soluble mediator. Histologic examination of lungs and liver and measurement of circulating TNF-α and IL-10 levels suggested that the inflammatory response is not diminished during cross-tolerance. Interestingly, aspirin, a non-specific cyclooxygenase (COX) inhibitor, partially blocked PAF-induced sudden death, whereas NS-398, a specific COX-2 inhibitor, completely protected mice from the lethal effects of PAF. Both COX inhibitors (at 20 mg/kg body wt) independently amplified the cross-tolerance exerted by higher dose of LPS, suggesting that COX-derived eicosanoids may be involved in these events. Thus, PAF does not seem to have a protective role in endotoxemia, but its effects are delayed by LPS in a COX-sensitive way. These findings are likely to shed light on basic aspects of the endotoxin cross-tolerance occurring in many disease conditions and may offer new opportunities for clinical intervention. PMID:27064683

  19. Sudden ionospheric disturbances in solar cycle 24

    NASA Astrophysics Data System (ADS)

    Bothmer, Volker; Bernert, Barbara

    2014-05-01

    Sudden ionospheric disturbances in solar cycle 24 Within the framework of the UN International Space Weather Initiative, and building upon the achievements of the International Heliophysical Year, the German project SIMONE (Sun Ionosphere MOnitoring NEtwork) operates several SID monitors provided by the University of Stanford. Here we present an overview of sudden ionospheric disturbances recorded since 2006 at the high school Gymnasium Walsrode until to date. The continous measurements allow a detailed comparison of locally measured SIDs with the general trend of solar activity during the current solar maximum. We further show that the measurements reveal specific information on the variable response of the dayside ionosphere to solar flares.

  20. Sudden Sensorineural Hearing Loss

    PubMed Central

    Kuhn, Maggie; Heman-Ackah, Selena E.; Shaikh, Jamil A.

    2011-01-01

    Sudden sensorineural hearing loss (SSNHL) is commonly encountered in audiologic and otolaryngologic practice. SSNHL is most commonly defined as sensorineural hearing loss of 30dB or greater over at least three contiguous audiometric frequencies occurring within a 72-hr period. Although the differential for SSNHL is vast, for the majority of patients an etiologic factor is not identified. Treatment for SSNHL of known etiology is directed toward that agent, with poor hearing outcomes characteristic for discoverable etiologies that cause inner ear hair cell loss. Steroid therapy is the current mainstay of treatment of idiopathic SSNHL in the United States. The prognosis for hearing recovery for idiopathic SSNHL is dependent on a number of factors including the severity of hearing loss, age, presence of vertigo, and shape of the audiogram. PMID:21606048

  1. Sudden death of feedlot cattle.

    PubMed

    Glock, R D; DeGroot, B D

    1998-01-01

    Sudden deaths or the sudden death syndrome are perceived as major concerns in cattle feedlots because most of these deaths occur in cattle near market weight. Etiology and preventive measures are poorly defined. The current literature indicates that sudden deaths are associated most commonly with digestive upsets. Death is thought to be the result of interactions between factors including acidosis, bloat, and endotoxemia. Trauma, peracute interstitial pneumonia, and other identifiable events are specifically defined but relatively uncommon. Enterotoxemia is of questionable significance as a cause of sudden deaths. PMID:9464913

  2. Unnatural sudden infant death

    PubMed Central

    Meadow, R.

    1999-01-01

    AIM—To identify features to help paediatricians differentiate between natural and unnatural infant deaths.
METHOD—Clinical features of 81 children judged by criminal and family courts to have been killed by their parents were studied. Health and social service records, court documents, and records from meetings with parents, relatives, and social workers were studied.
RESULTS—Initially, 42 children had been certified as dying from sudden infant death syndrome (SIDS), and 29 were given another cause of natural death. In 24 families, more than one child died; 58died before the age of 6 months and most died in the afternoon or evening. Seventy per cent had experienced unexplained illnesses; over half were admitted to hospital within the previous month, and 15 had been discharged within 24 hours of death. The mother, father, or both were responsible for death in 43, five, and two families, respectively. Most homes were disadvantaged—no regular income, receiving income support—and mothers smoked. Half the perpetrators had a history of somatising or factitious disorder. Death was usually by smothering and 43% of children had bruises, petechiae, or blood on the face.
CONCLUSIONS—Although certain features are indicative of unnatural infant death, some are also associated with SIDS. Despite the recent reduction in numbers of infants dying suddenly, inadequacies in the assessment of their deaths exist. Until a thorough postmortem examination is combined with evaluation of the history and circumstances of death by an experienced paediatrician, most cases of covert fatal abuse will go undetected. The term SIDS requires revision or abandonment.

 PMID:10325752

  3. Magnetic helicity in emerging solar active regions

    SciTech Connect

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

    2014-04-10

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

  4. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, Anthony M.

    1998-06-02

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

  5. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, Anthony M.

    1996-01-01

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

  6. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, A.M.

    1998-06-02

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

  7. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, A.M.

    1996-01-30

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

  8. Supergranule Diffusion and Active Region Decay

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.; Choudhary, Debi Prasad

    2004-01-01

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

  9. Proper Motion Of Emerging Active Regions

    NASA Astrophysics Data System (ADS)

    Tian, Lirong

    2009-05-01

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

  10. Models of Impulsively Heated Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Airapetian, Vladimir; Klimchuk, J.

    2009-05-01

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

  11. Sudden Fiction: What Is It?

    ERIC Educational Resources Information Center

    Tindall, James

    Initially an assignment for a library science class, this paper presents various definitions of the current creative writing phenomenon called "sudden fiction" (very short short stories with concise character sketches, and terse tales limited in length to several pages). The paper includes: (1) a list of well regarded sudden fiction anthologies;…

  12. Sudden flaccid paralysis.

    PubMed

    Tariq, Mohammad; Peshin, Rohit; Ellis, Oliver; Grover, Karan

    2015-01-01

    Periodic thyrotoxic paralysis is a genetic condition, rare in the West and in Caucasians. Thyrotoxicosis, especially in western hospitals, is an easily overlooked cause of sudden-onset paralysis. We present a case of a 40-year-old man who awoke one morning unable to stand. He had bilateral lower limb flaccid weakness of 0/5 with reduced reflexes and equivocal plantars; upper limbs were 3/5 with reduced tone and reflexes. ECG sinus rhythm was at a rate of 88/min. PR interval was decreased and QT interval increased. Bloods showed potassium of 1.8 mEq/L (normal range 3.5-5), free T4 of 29.2 pmol/L (normal range 6.5-17) and thyroid-stimulating hormone (TSH) of <0.01 mIU/L (normal range 0.35-4.94). Random urinary potassium was 8.8 mEq/L (normal range 12.5-62.5). The patient was admitted initially to intensive therapy unit and given intravenous potassium. His symptoms resolved within 24 h. He was diagnosed with thyrotoxic periodic paralysis. He was discharged on carbimazole and propanolol, and follow-up was arranged in the endocrinology clinic. PMID:25566931

  13. Sudden infant death syndrome

    PubMed Central

    Hunt, Carl E.; Hauck, Fern R.

    2006-01-01

    Sudden infant death syndrome (SIDS) continues to be the most common cause of postneonatal infant death. SIDS is a complex, multifactorial disorder, the cause of which is still not fully understood. However, much is known now about environmental risk factors, some of which are modifiable. These include maternal and antenatal risk factors such as smoking during pregnancy, as well as infant-related risk factors such as non-supine sleeping position and soft bedding. Emerging evidence also substantiates an expanding number of genetic risk factors. Interactions between environmental and genetic risk factors may be of critical importance in determining an infant's actual risk of SIDS. Although no practical way exists to identify which infants will die of SIDS, nor is there a safe and proven prevention strategy even if identification were feasible, reducing exposure to modifiable risk factors has helped to lower the incidence of SIDS. Current challenges include wider dissemination of guidelines to all people who care for infants, dissemination of guidelines in culturally appropriate ways, and surveillance of SIDS trends and other outcomes associated with implementation of these guidelines. PMID:16785462

  14. Defining Sudden Stratospheric Warmings

    NASA Astrophysics Data System (ADS)

    Butler, Amy; Seidel, Dian; Hardiman, Steven; Butchart, Neal; Birner, Thomas; Match, Aaron

    2015-04-01

    The general form of the definition for Sudden Stratospheric Warmings (SSWs) is largely agreed to be a reversal of the temperature gradient and of the zonal circulation polewards of 60° latitude at the 10 hPa level, as developed by the World Meteorological Organization (WMO) in the 1960s and 1970s. However, the details of the definition and its calculation are ambiguous, resulting in inconsistent classifications of SSW events. These discrepancies are problematic for understanding the observed frequency and statistical relationships with SSWs, and for maintaining a robust metric with which to assess wintertime stratospheric variability in observations and climate models. To provide a basis for community-wide discussion, we examine how the SSW definition has changed over time and how sensitive the detection of SSWs is to the definition used. We argue that the general form of the SSW definition should be clarified to ensure that it serves current research and forecasting purposes, and propose possible ways to update the definition.

  15. Solar irradiance variations due to active regions

    SciTech Connect

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

    1982-05-15

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

  16. Observations of an active region filament

    NASA Astrophysics Data System (ADS)

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

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

  17. [Genetics of sudden unexplained death].

    PubMed

    Campuzano, Oscar; Allegue, Catarina; Brugada, Ramon

    2014-03-20

    Sudden unexplained death is defined by death without a conclusive diagnosis after autopsy and it is responsible for a large percentage of sudden deaths. The progressive interaction between genetics and forensics in post-mortem studies has identified inheritable alterations responsible for pathologies associated with arrhythmic sudden death. The genetic diagnosis of the deceased enables the undertaking of preventive measures in family members, many of them asymptomatic but at risk. The implications of this multidisciplinary translational medical approach are complex, requiring the dedication of a specialized team. PMID:24018251

  18. Pederson Current Dissipation In Emerging Active Regions

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  19. Localizing Region-Based Active Contours

    PubMed Central

    Lankton, Shawn; Tannenbaum, Allen

    2009-01-01

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

  20. HEROES Observations of a Quiescent Active Region

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  1. Sudden Cardiac Death Risk Stratification

    PubMed Central

    Deyell, Marc W.; Krahn, Andrew D.; Goldberger, Jeffrey J.

    2015-01-01

    Arrhythmic sudden cardiac death (SCD) may be due to ventricular tachycardia/fibrillation (SCD-VT/VF) or pulseless electrical activity/asystole. Effective risk stratification to identify patients at risk of arrhythmic SCD is essential for targeting our health care and research resources to tackle this important public health issue. Although our understanding of SCD due to pulseless electrical activity/asystole is growing, the overwhelming majority of research in risk stratification has focused on SCD-VT/VF. This review focuses on existing and novel risk stratification tools for SCD-VT/VF. For patients with left ventricular dysfunction and/or myocardial infarction, advances in imaging, measures of cardiac autonomic function, and measures of repolarization have shown considerable promise in refining risk. Yet the majority of SCD-VT/VF occurs in patients without known cardiac disease. Biomarkers and novel imaging techniques may provide further risk stratification in the general population beyond traditional risk stratification for coronary artery disease alone. Despite these advances, significant challenges in risk stratification remain that must be overcome before a meaningful impact on SCD can be realized. PMID:26044247

  2. Radio magnetography of the solar active regions

    NASA Astrophysics Data System (ADS)

    Gelfreikh, G. B.; Shibasaki, K.

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

  3. Sudden death in eating disorders

    PubMed Central

    Jáuregui-Garrido, Beatriz; Jáuregui-Lobera, Ignacio

    2012-01-01

    Eating disorders are usually associated with an increased risk of premature death with a wide range of rates and causes of mortality. “Sudden death” has been defined as the abrupt and unexpected occurrence of fatality for which no satisfactory explanation of the cause can be ascertained. In many cases of sudden death, autopsies do not clarify the main cause. Cardiovascular complications are usually involved in these deaths. The purpose of this review was to report an update of the existing literature data on the main findings with respect to sudden death in eating disorders by means of a search conducted in PubMed. The most relevant conclusion of this review seems to be that the main causes of sudden death in eating disorders are those related to cardiovascular complications. The predictive value of the increased QT interval dispersion as a marker of sudden acute ventricular arrhythmia and death has been demonstrated. Eating disorder patients with severe cardiovascular symptoms should be hospitalized. In general, with respect to sudden death in eating disorders, some findings (eg, long-term eating disorders, chronic hypokalemia, chronically low plasma albumin, and QT intervals >600 milliseconds) must be taken into account, and it must be highlighted that during refeeding, the adverse effects of hypophosphatemia include cardiac failure. Monitoring vital signs and performing electrocardiograms and serial measurements of plasma potassium are relevant during the treatment of eating disorder patients. PMID:22393299

  4. FIP bias in a sigmoidal active region

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  5. The composition of a coronal active region

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  6. Electric and magnetic fields measured during a sudden impulse

    NASA Technical Reports Server (NTRS)

    Schutz, S.; Adams, G. J.; Mozer, F. S.

    1974-01-01

    The electric field in the ionosphere and the magnetic field at the earth's surface in the mid-latitude region were both measured during a sudden impulse. Ionospheric conductivities deduced from this data were consistent with expectations, thus suggesting that the fluctuations in the magnetic field at the earth's surface were caused by overhead ionospheric currents that were driven by an electric field associated with the sudden impulse.

  7. Anger Style, Psychopathology, and Regional Brain Activity

    PubMed Central

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

    2010-01-01

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

  8. Sudden cardiac death & the Reverse Dodo Verdict.

    PubMed

    Healy, David; Howe, Gareth; Mangin, Derelie; Le Noury, Joanna

    2014-01-01

    Adverse effects of treatment on cardiac QT intervals were first reported 50 years ago. A clear link to sudden death was established, but the problem remained relatively unknown. The issue of treatment related effects on the heart, and the contribution this might make to sudden cardiac deaths in general, came more clearly into focus 20 years ago, linked to regulatory actions. In an era of polypharmacy, and mixing of prescribed and non-prescribed pharmacologically active agents it is now becoming increasingly clear that unanticipated cardiac effects may be common and a significant cause of mortality. There is likely underreporting and also underdiagnosis, as recognition requires a timely ECG. This paper proposes two methods to handle the problem. PMID:24902504

  9. Advanced Electrocardiographic Predictors of Sudden Death in Familial Dysautonomia

    NASA Technical Reports Server (NTRS)

    Solaimanzadeh, I.; Schlegel, T. T.; Greco, E. C.; DePalma, J. L.; Starc, V.; Marthol, H.; Tutaj, M.; Buechner, S.; Axelrod, F. B.; Hilz, M. J.

    2007-01-01

    To identify accurate predictors for the risk of sudden death in patients with familial dysautonomia (FD). Ten-minute resting high-fidelity 12-lead ECGs were obtained from 14 FD patients and 14 age/gender-matched healthy subjects. Multiple conventional and advanced ECG parameters were studied for their ability to predict sudden death in FD over a subsequent 4.5-year period, including multiple indices of linear and non-linear heart rate variability (HRV); QT variability; waveform complexity; high frequency QRS; and derived Frank-lead parameters. Four of the 14 FD patients died suddenly during the follow-up period, usually with concomitant pulmonary disorder. The presence of low vagally-mediated HRV was the ECG finding most predictive of sudden death. Concomitant left ventricular hypertrophy and other ECG abnormalities such as increased QTc and JTc intervals, spatial QRS-T angles, T-wave complexity, and QT variability were also present in FD patients, suggesting that structural heart disease is fairly common in FD. Although excessive or unopposed cardiac vagal (relative to sympathetic) activity has been postulated as a contributor to sudden death in FD, the presence of low vagally-mediated HRV was paradoxically the best predictor of sudden death. However, we suggest that low vagally-mediated HRV be construed not as a direct cause of sudden death in FD, but rather as an effect of concurrent pathological processes, especially hypoxia due to pulmonary disorders and sleep apnea, that themselves increase the risk of sudden death in FD and simultaneously diminish HRV. We speculate that adenosine may play a role in sudden death in FD, possibly independently of vagal activity, and that adenosine inhibitors such as theophylline might therefore be useful as prophylaxis in this disorder.

  10. The Life Cycle of Active Region Magnetic Fields

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  11. MAGNETIC ENERGY SPECTRA IN SOLAR ACTIVE REGIONS

    SciTech Connect

    Abramenko, Valentyna; Yurchyshyn, Vasyl

    2010-09-01

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

  12. Sudden death of effective entanglement

    SciTech Connect

    Roszak, K.; Horodecki, P.; Horodecki, R.

    2010-04-15

    Sudden death of entanglement is a well-known effect resulting from the finite volume of separable states. We study the case when the observer has a limited measurement capability and analyze the effective entanglement (i.e., entanglement minimized over the output data). We show that in the well-defined system of two quantum dots monitored by single-electron transistors, one may observe a sudden death of effective entanglement when real, physical entanglement is still alive. For certain measurement setups, this occurs even for initial states for which sudden death of physical entanglement is not possible at all. The principles of the analysis may be applied to other analogous scenarios, such as estimation of the parameters arising from quantum process tomography.

  13. Recurrent flares in active region NOAA 11283

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  14. The Limit of Free Magnetic Energy in Active Regions

    NASA Technical Reports Server (NTRS)

    Moore, Ron; Falconer, David; Sterling, Alphonse

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  16. Sudden cardiac death in athletes.

    PubMed

    Schmied, C; Borjesson, M

    2014-02-01

    A 'paradox of sport' is that in addition to the undisputed health benefits of physical activity, vigorous exertion may transiently increase the risk of acute cardiac events. In general, the risk of sudden cardiac death (SCD) approximately doubles during physical activity and is 2- to 3-fold higher in athletes compared to nonathletes. The incidence of SCD in young athletes is in fact very low, at around 1-3 per 100,000, but attracts much public attention. Variations in incidence figures may be explained by the methodology used for data collection and more importantly by differences between subpopulations of athletes. The incidence of SCD in older (≥ 35 years) athletes is higher and may be expected to rise, as more and older individuals take part in organized sports. SCD is often the first clinical manifestation of a potentially fatal underlying cardiovascular disorder and usually occurs in previously asymptomatic athletes. In the young (<35 years), SCD is mainly due to congenital/inherited cardiac abnormalities, whilst coronary artery disease (CAD) is the most common cause in older athletes. Cardiac screening including family/personal history, physical examination and resting electrocardiogram (ECG) may identify individuals at risk and has the potential to decrease the risk of SCD in young athletes. Screening including the ECG has a high sensitivity for underlying disease in young athletes, but the specificity needs to be improved, whereas the sensitivity of screening without the use of ECG is very low. The screening modality recommended for young athletes is of limited value in older athletes, who should receive individualized screening with cardiac stress testing for patients with high risk of underlying CAD. As cardiovascular screening will never be able to identify all athletes at risk, adequate preparedness is vital in case of a potentially fatal event at the sporting arena/facility. Firstly, we will review the magnitude of the problem of SCD in athletes of

  17. Sudden trust collapse in networked societies

    NASA Astrophysics Data System (ADS)

    da Gama Batista, João; Bouchaud, Jean-Philippe; Challet, Damien

    2015-03-01

    Trust is a collective, self-fulfilling phenomenon that suggests analogies with phase transitions. We introduce a stylized model for the build-up and collapse of trust in networks, which generically displays a first order transition. The basic assumption of our model is that whereas trustworthiness begets trustworthiness, panic also begets panic, in the sense that a small decrease in trustworthiness may be amplified and ultimately lead to a sudden and catastrophic drop of collective trust. We show, using both numerical simulations and mean-field analytic arguments, that there are extended regions of the parameter space where two equilibrium states coexist: a well-connected network where global confidence is high, and a poorly connected network where global confidence is low. In these coexistence regions, spontaneous jumps from the well-connected state to the poorly connected state can occur, corresponding to a sudden collapse of trust that is not caused by any major external catastrophe. In large systems, spontaneous crises are replaced by history dependence: whether the system is found in one state or in the other essentially depends on initial conditions. Finally, we document a new phase, in which agents are well connected yet distrustful.

  18. Infant dreaming and fetal memory: a possible explanation of sudden infant death syndrome.

    PubMed

    Christos, G A

    1995-04-01

    During rapid-eye-movement sleep, when we dream, the brain is thought to be processing stored memory. The memory of a newborn infant is dominated by its fetal experience, and the infant is likely to dream about its life in the womb. Research with lucid (or conscious) dreaming has shown that dream images are supported by the corresponding body actions, using those muscles which remain active during rapid-eye-movement sleep. We suggest that sudden infant death syndrome or cot death may be a result of an infant dreaming about its life (or memory) as a fetus. In the course of that dream, since a fetus does not breathe (in the usual sense) the infant may cease to breathe and may die. This simple hypothesis is consistent with all of the known facts about sudden infant death syndrome (pathological and epidemiological), such as the age at death curve (the observed exponential decay and possibly the peak at 2-3 months), the higher risk with the prone sleeping position (but not excluding the supine position), and the observed climatic variation (seasonal and regional) in the incidence of sudden infant death syndrome. Many of these well-established facts have no other known explanation and other theories can generally only account for a few of the known facts about sudden infant death syndrome. Our hypothesis is also supported by recent findings that, as a group, sudden infant death syndrome infants have a higher proportion of rapid-eye-movement sleep, and also that they have an average higher heart rate (corresponding to possible fetal dreams) but only during rapid-eye-movement sleep.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7666822

  19. Sudden Arrhythmia Death Syndromes (SADS) Foundation

    MedlinePlus

    ... all proceeds benefiting the SADS Foundation (Sudden Arrhythmia Death Syndrome). Each year 4,000 young Americans die ... Investigator Awardees 5/19/2016 The Sudden Arrhythmia Death Syndromes (SADS) Foundation announces the winners for the ...

  20. Sudden Cardiac Arrest (SCA) Risk Assessment

    MedlinePlus

    ... Find a Specialist Share Twitter Facebook SCA Risk Assessment Sudden Cardiac Arrest (SCA) occurs abruptly and without ... of all ages and health conditions. Start Risk Assessment The Sudden Cardiac Arrest (SCA) Risk Assessment Tool ...

  1. Sudden Infant Death Syndrome: Facts for Caregivers.

    ERIC Educational Resources Information Center

    Texas Child Care, 2000

    2000-01-01

    Presents risk factors and prevention measures related to Sudden Infant Death Syndrome. Offers infant sleep recommendations and five discussion questions to test knowledge of Sudden Infant Death Syndrome. (DLH)

  2. Tracked Active Region Patches for MDI and HMI

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  3. Sudden Cardiac Death in Athletes.

    PubMed

    Wasfy, Meagan M; Hutter, Adolph M; Weiner, Rory B

    2016-01-01

    There are clear health benefits to exercise; even so, patients with cardiac conditions who engage in exercise and athletic competition may on rare occasion experience sudden cardiac death (SCD). This article reviews the epidemiology and common causes of SCD in specific athlete populations. There is ongoing debate about the optimal mechanism for SCD prevention, specifically regarding the inclusion of the ECG and/or cardiac imaging in routine preparticipation sports evaluation. This controversy and contemporary screening recommendations are also reviewed. PMID:27486488

  4. Sudden Cardiac Death in Athletes

    PubMed Central

    Wasfy, Meagan M.; Hutter, Adolph M.; Weiner, Rory B.

    2016-01-01

    There are clear health benefits to exercise; even so, patients with cardiac conditions who engage in exercise and athletic competition may on rare occasion experience sudden cardiac death (SCD). This article reviews the epidemiology and common causes of SCD in specific athlete populations. There is ongoing debate about the optimal mechanism for SCD prevention, specifically regarding the inclusion of the ECG and/or cardiac imaging in routine preparticipation sports evaluation. This controversy and contemporary screening recommendations are also reviewed. PMID:27486488

  5. Pediatric Sudden Sensorineural Hearing Loss.

    PubMed

    Kizilay, Ahmet; Koca, Çiğdem Firat

    2016-06-01

    Sudden sensorineural hearing loss is defined as sudden unilateral or bilateral sensorineural hearing loss with at least 30 dB decrease in threshold in 3 contiguous test frequencies occurring over 72 hours or less. It is rare among children. The mechanism of the process and prognosis of the disorder remains unclear. The current incidence of sudden sensorineural hearing loss among pediatric population is unknown. The authors carried out a retrospective chart analysis of patients under 15 years of age from 2004 to 2015, who consulted to the Otolaryngology Head and Neck Surgery Department of Inonu University Medical Faculty. Age, sex, number of affected ear and side, audiometric evaluations, medical follow-up, treatment method, duration of treatment recovery, associated complaints; tinnitus and/or vertigo, presence of mumps disease were recorded for each patient. A 4-frequency pure-tone average (500, 1000, 2000, and 4000 Hz) was calculated for each ear. Complete recovery, defined as some hearing level compared with the nonaffected ear, was observed in 3 patients (21.4 %) and there was no partial hearing recovery. The hearing loss of 11 patient remained unchanged after prednisolone treatment. Two of the 11 patients had bilaterally total sensorineural hearing loss and evaluated as appropriate for cochlear implantation. Sex of patient and laterality of hearing loss were not correlated with hearing recovery. Sensorineural hearing loss among pediatrics has been the issue of otolaryngologists. The incidence, etiology, and treatment methods should be more studied. PMID:27171971

  6. A Fractal Dimension Survey of Active Region Complexity

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  8. GLOBAL DYNAMICS OF SUBSURFACE SOLAR ACTIVE REGIONS

    SciTech Connect

    Jouve, L.; Brun, A. S.

    2013-01-01

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

  9. OBSERVING CORONAL NANOFLARES IN ACTIVE REGION MOSS

    SciTech Connect

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

    2013-06-10

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

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

    ERIC Educational Resources Information Center

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

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

  11. Software Displays Data on Active Regions of the Sun

    NASA Technical Reports Server (NTRS)

    Golightly, Mike; Weyland, Mark; Raben, Vern

    2011-01-01

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

  12. Radiofrequency Ablation to Prevent Sudden Cardiac Death

    PubMed Central

    Atoui, Moustapha; Gunda, Sampath; Lakkireddy, Dhanunjaya; Mahapatra, Srijoy

    2015-01-01

    Radiofrequency ablation may prevent or treat atrial and ventricular arrhythmias. Since some of these arrhythmias are associated with sudden cardiac death, it has been hypothesized that ablation may prevent sudden death in certain cases. We performed a literature search to better understand under which circumstances ablation may prevent sudden death and found little randomized data demonstrating the long-term effects of ablation. Current literature shows that ablation clearly prevents symptoms of arrhythmia and may reduce the incidence of sudden cardiac death in select patients, although data does not indicate improved mortality. Ongoing clinical trials are needed to better define the role of ablation in preventing sudden cardiac death. PMID:26306130

  13. Stratospheric sudden warming and lunar tide

    NASA Astrophysics Data System (ADS)

    Yamazaki, Yosuke; Kosch, Michael

    2016-07-01

    A stratospheric sudden warming is a large-scale disturbance in the middle atmosphere. Recent studies have shown that the effect of stratospheric sudden warnings extends well into the upper atmosphere. A stratospheric sudden warming is often accompanied by an amplification of lunar tides in the ionosphere/theremosphere. However, there are occasionally winters when a stratospheric sudden warming occurs without an enhancement of the lunar tide in the upper atmosphere, and other winters when large lunar tides are observed without a strong stratospheric sudden warming. We examine the winters when the correlation breaks down and discuss possible causes.

  14. Disrupted functional brain connectome in unilateral sudden sensorineural hearing loss.

    PubMed

    Xu, Haibo; Fan, Wenliang; Zhao, Xueyan; Li, Jing; Zhang, Wenjuan; Lei, Ping; Liu, Yuan; Wang, Haha; Cheng, Huamao; Shi, Hong

    2016-05-01

    Sudden sensorineural hearing loss (SSNHL) is generally defined as sensorineural hearing loss of 30 dB or greater over at least three contiguous audiometric frequencies and within a three-day period. This hearing loss is usually unilateral and can be associated with tinnitus and vertigo. The pathogenesis of unilateral sudden sensorineural hearing loss is still unknown, and the alterations in the functional connectivity are suspected to involve one possible pathogenesis. Despite scarce findings with respect to alterations in brain functional networks in unilateral sudden sensorineural hearing loss, the alterations of the whole brain functional connectome and whether these alterations were already in existence in the acute period remains unknown. The aim of this study was to investigate the alterations of brain functional connectome in two large samples of unilateral sudden sensorineural hearing loss patients and to investigate the correlation between unilateral sudden sensorineural hearing loss characteristics and changes in the functional network properties. Pure tone audiometry was performed to assess hearing ability. Abnormal changes in the peripheral auditory system were examined using conventional magnetic resonance imaging. The graph theoretical network analysis method was used to detect brain connectome alterations in unilateral sudden sensorineural hearing loss. Compared with the control groups, both groups of unilateral SSNHL patients exhibited a significantly increased clustering coefficient, global efficiency, and local efficiency but a significantly decreased characteristic path length. In addition, the primary increased nodal strength (e.g., nodal betweenness, hubs) was observed in several regions primarily, including the limbic and paralimbic systems, and in the auditory network brain areas. These findings suggest that the alteration of network organization already exists in unilateral sudden sensorineural hearing loss patients within the acute period

  15. Analysis of sudden variations in photospheric magnetic fields during a large flare and their influences in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Kumar, Brajesh; Raja Bayanna, Ankala; Venkatakrishnan, Parameswaran; Kuchandy Mathew, Shibu

    2016-08-01

    The solar active region NOAA 11719 produced a large two-ribbon flare on 2013 April 11. We have investigated sudden variations in the photospheric magnetic fields in this active region during the flare by employing magnetograms obtained in the spectral line Fe I 6173 Å acquired by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) spacecraft. The analysis of the line-of-sight magnetograms from HMI show sudden and persistent magnetic field changes at different locations of the active region before the onset of the flare and during the flare. The vector magnetic field observations available from HMI also show coincident variations in the total magnetic field strength and its inclination angle at these locations. Using the simultaneous Dopplergrams obtained from HMI, we observe perturbations in the photospheric Doppler signals following the sudden changes in the magnetic fields in the aforementioned locations. The power spectrum analysis of these velocity signals shows enhanced acoustic power in these affected locations during the flare as compared to the pre-flare condition. Accompanying these observations, we have also used nearly simultaneous chromospheric observations obtained in the spectral line Hα 6562.8 Å by the Global Oscillation Network Group (GONG) to study the evolution of flare-ribbons and intensity oscillations in this active region. The Hα intensity oscillations also show enhanced oscillatory power during the flare in the aforementioned locations. These results indicate that the transient Lorentz force associated with sudden changes in the magnetic fields could drive localized photospheric and chromospheric oscillations, like the flare-induced oscillations in the solar atmosphere.

  16. 3D MHD Models of Active Region Loops

    NASA Technical Reports Server (NTRS)

    Ofman, Leon

    2004-01-01

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

  17. [SPORTS-RELATED SUDDEN DEATH: LESSONS FROM THE FRENCH REGISTRY].

    PubMed

    Marijon, Eloi; Bougouin, Wulfran; Jouven, Xavier

    2015-09-01

    So far, sports-related sudden death has been mainly studied through young competitive athletes. The national sports-related sudden death French registry (2005-2010) is the first study evaluating sudden death during sports activities in the general population, estimating that approximately 1000 cases occur each year in France. The vast majority occurs among middle age men practicing recreational activities, with women presenting a very low risk (up to 30-fold lower) compared to men. Outcomes dramatically vary across districts with survival to hospital discharge from 0 to 50%. Those differences are mainly the result of major disparities between districts regarding cardiopulmonary resuscitation initiated by bystanders. Coronary artery disease remains the most frequent cardiovascular disease associated with such events. PMID:26619725

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

    SciTech Connect

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

    2012-11-01

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

  19. A large family characterised by nocturnal sudden death

    PubMed Central

    van den Berg, M.P.; Viersma, J.W.; Beaufort-Krol, G.C.M.; Bink-Boelkens, M.Th.E.; Bezzina, C.R.; Veldkamp, M.W.; Brouwer, J.; Haaksma, J.; van Tintelen, J.P.; van Langen, I.M.; Wouda, A.A.; Wilde, A.A.M.

    2002-01-01

    Background We recently identified a novel mutation in large family characterised by premature nocturnal sudden death. In the present paper we provide an overview of the findings in this family. Methods From 1958 onwards, when the first patient presented, we collected clinical data on as many family members as possible. After identification in 1998 of the underlying genetic disorder (SCN5A, 1795insD), genotyping was performed diagnostically. Results Since 1905 unexplained sudden death occurred in 26 family members, 17 of whom died during the night. Besides sudden death, symptomatology was rather limited; only six patients reported syncopal attacks. In one of them, a 13-year-old boy, asystolic episodes up to nine seconds were documented. Until now, the mutation has been found in 114 family members (57 males, 57 females). Carriers of the mutant gene exhibited bradycardia-dependent QT-prolongation, intrinsic sinus node dysfunction, generalised conduction abnormalities, a paucity of ventricular ectopy, and the Brugada sign. Cardiomyopathy or other structural abnormalities were not found in any of the carriers. Electrophysiological studies showed that mutant channels were characterised by markedly reduced INa amplitude, a positive shift of voltage-dependence of activation and a substantial negative shift of voltage-dependence of inactivation of INa. From 1978 onwards, a pacemaker for anti-brady pacing was implanted for prevention of sudden death. In patients in whom a prophylactic pacemaker was implanted no unexplained sudden death occurred, whereas 5 sudden deaths occurred in the group of patients who did not receive a pacemaker. Conclusion We have described a large family with a SCN5A-linked disorder (1795insD) with features of LQT3, Brugada syndrome and familial conduction system disease. Anti-brady pacing was successful in preventing sudden death. The mode of death is possibly bradycardic. ImagesFigure 5 PMID:25696119

  20. Regional Observation of Seismic Activity in Baekdu Mountain

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    PubMed

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

    2005-02-15

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

  2. Genetics of channelopathies associated with sudden cardiac death

    PubMed Central

    Campuzano, Oscar; Sarquella-Brugada, Georgia; Brugada, Ramon; Brugada, Josep

    2015-01-01

    Recent technological advances in cardiology have resulted in new guidelines for the diagnosis, treatment and prevention of diseases. Despite these improvements, sudden death remains one of the main challenges to clinicians because the majority of diseases associated with sudden cardiac death are characterized by incomplete penetrance and variable expressivity. Hence, patients may be unaware of their illness, and physical activity can be the trigger for syncope as first symptom of the disease. Most common causes of sudden cardiac death are congenital alterations and structural heart diseases, although a significant number remain unexplained after comprehensive autopsy. In these unresolved cases, channelopathies are considered the first potential cause of death. Since all these diseases are of genetic origin, family members could be at risk, despite being asymptomatic. Genetics has also benefited from technological advances, and genetic testing has been incorporated into the sudden death field, identifying the cause in clinically affected patients, asymptomatic family members and post-mortem cases without conclusive diagnosis. This review focuses on recent advances in the genetics of channelopathies associated with sudden cardiac death. PMID:26566530

  3. Prediction of Active-Region CME Productivity from Magnetograms

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  4. Sudden unexpected death due to Graves' disease during physical altercation.

    PubMed

    Wei, Dengming; Yuan, Xiaogang; Yang, Tiantong; Chang, Lin; Zhang, Xiang; Burke, Allen; Fowler, David; Li, Ling

    2013-09-01

    We report a case of a 30-year-old woman who suddenly collapsed after having a physical altercation with her husband. Despite immediate resuscitation, she died on arrival at the hospital. The victim's parents requested an autopsy because they believed that their daughter was killed by her husband. Postmortem examination revealed that the victim had a diffusely enlarged thyroid gland and cardiomegaly with left ventricular hypertrophy. There was no evidence of significant trauma on the body. Further postmortem thyroid function tests and review of her medical history indicated that her death was due to Graves' disease. To the best of our knowledge, this is the first case reported of sudden death due to cardiac arrhythmia from Graves' disease induced by physical and emotional stress associated with the criminal activity of another person. The autopsy findings are described. In addition, the literature is reviewed and the significance of postmortem evaluation of thyroid hormones in the cases of sudden death is discussed. PMID:23919315

  5. Extreme sacrifice: sudden cardiac death in the US Fire Service

    PubMed Central

    2013-01-01

    Firefighting is a hazardous profession which has claimed on average the lives of 105 US firefighters per year for the past decade. The leading cause of line-of-duty mortality is sudden cardiac death, which accounts for approximately 45% of all firefighter duty-related fatalities. Strenuous physical activity, emotional stress, and environmental pollutants all strain the cardiovascular system, and each can increase the risk of sudden cardiac events in susceptible individuals. Sudden cardiac death is more likely to occur during or shortly after emergency duties such as fire suppression, despite the fact that these duties comprise a relatively small proportion of firefighters' annual duties. Additionally, cardiac events are more likely to occur in firefighters who possess an excess of traditional risk factors for cardiovascular disease along with underlying atherosclerosis and/or structural heart disease. In this review, we propose a theoretical model for the interaction between underlying cardiovascular disease in firefighters and the multifactorial physiological strain of firefighting. PMID:23849605

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

    SciTech Connect

    Schmelz, J. T.; Pathak, S.

    2012-09-10

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

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

    PubMed Central

    Haque, Md. Nuruzzaman

    2016-01-01

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

  8. DISTRIBUTION OF ELECTRIC CURRENTS IN SOLAR ACTIVE REGIONS

    SciTech Connect

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

    2014-02-10

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

  9. Photospheric Magnetic Diffusion by Measuring Moments of Active Regions

    NASA Astrophysics Data System (ADS)

    Engell, Alexander; Longcope, D.

    2013-07-01

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

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

    PubMed

    Urquhart, Donna M; Hodges, Paul W

    2005-05-01

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

  11. Solar Irradiance Variations on Active Region Time Scales

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  12. Radio Coronal Magnetography of a Large Active Region

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    NASA Astrophysics Data System (ADS)

    Yu, Xingfeng; Yao, Jinxing

    1995-09-01

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

  14. [Sudden death in young athletes].

    PubMed

    Gojanovic, B; Feihl, F; Gremion, G; Waeber, B

    2007-02-01

    Sudden cardiac death in a young athlete is a tragic and marking event, even though the media attention it gets is more important than its incidence (1-2/100000 per year). The main etiology is hypertrophic cardiomyopathy, followed by coronary artery anomalies. Sometimes signs of myocarditis are found at autopsy. The pre-participation examination recommandations ask for oriented history and physical examination, routine EKG being controversial. A systematic screening program in Italy has reduced the occurrence of such deaths, which statistics are non-existant in Switzerland. It would be appropriate to implement a standardized pre-participation examination, as well as to make sure that the trainers, teachers and athletes themselves are able to recognize the frequent warning symptoms. PMID:17330410

  15. The Sudden Stratospheric Warming Atlas

    NASA Astrophysics Data System (ADS)

    Sjoberg, J. P.; Butler, A. H.; Seidel, D. J.

    2015-12-01

    Sudden stratospheric warmings (SSWs) are large and rapid temperature increases in the polar stratosphere associated with a complete reversal of the climatological westerly winds in wintertime. These extreme events can have substantial impacts on wintertime surface climate, such as cold air outbreaks over North America and Eurasia, or anomalous warming over Greenland. Here we promote our progress towards a new atlas of historical SSW events and their impacts on the surface. The SSW atlas contains a variety of metrics, time series, maps, and animations for individual SSW events. The atlas will allow users to examine the structure and development of individual SSWs, the variability between events, the surface impacts in temperature and precipitation, and the impacts of SSWs during years with certain tropospheric signatures, like El Niño or La Niña winters.

  16. Sudden stratospheric warmings as catastrophes

    NASA Technical Reports Server (NTRS)

    Chao, W. C.

    1985-01-01

    The sudden stratospheric warming (SSW) process is qualitatively studied using a conceptual and numerical approach guided by catastrophe theory. A simple example of a catastrophe taken from nonlinear dynamics is given, and results from previous modelling studies of SSW are interpreted in light of catastrophe theory. Properties of this theory such as hysteresis, cusp, and triggering essential to SSW are numerically demonstrated using the truncated quasi-geostrophic beta-plane model of Holton and Mass (1976). A qualitative explanation of the transition from the steady regime to the vacillation regime is given for the Holton and Mass model in terms of the topographically induced barotropic Rossby wave instability. Some implications for the simulation and prediction of SSW are discussed.

  17. Sudden Cardiac Arrest in Pediatrics.

    PubMed

    Scheller, RoseAnn L; Johnson, Laurie; Lorts, Angela; Ryan, Thomas D

    2016-09-01

    Sudden cardiac arrest (SCA) in the pediatric population is a rare and potentially devastating occurrence. An understanding of the differential diagnosis for the etiology of the cardiac arrest allows for the most effective emergency care and provides the patient with the best possible outcome. Pediatric SCA can occur with or without prodromal symptoms and may occur during exercise or rest. The most common cause is arrhythmia secondary to an underlying channelopathy, cardiomyopathy, or myocarditis. After stabilization, evaluation should include electrocardiogram, chest radiograph, and echocardiogram. Management should focus on decreasing the potential for recurring arrhythmia, maintaining cardiac preload, and thoughtful medication use to prevent exacerbation of the underlying condition. The purpose of this review was to provide the emergency physician with a concise and current review of the incidence, differential diagnosis, and management of pediatric patients presenting with SCA. PMID:27585126

  18. Sudden decrease in physical activity evokes adipocyte hyperplasia in 70- to 77-day-old rats but not 49- to 56-day-old rats.

    PubMed

    Company, Joseph M; Roberts, Michael D; Toedebusch, Ryan G; Cruthirds, Clayton L; Booth, Frank W

    2013-12-15

    The cessation of physical activity in rodents and humans initiates obesogenic mechanisms. The overall purpose of the current study was to determine how the cessation of daily physical activity in rats at 49-56 days of age and at 70-77 days of age via wheel lock (WL) affects adipose tissue characteristics. Male Wistar rats began voluntary running at 28 days old and were either killed at 49-56 days old or at 70-77 days old. Two cohorts of rats always had wheel access (RUN), a second two cohorts of rats had wheel access restricted during the last 7 days (7d-WL), and a third two cohorts of rats did not have access to a voluntary running wheel after the first 6 days of (SED). We observed more robust changes with WL in the 70- to 77-day-old rats. Compared with RUN rats, 7d-WL rats exhibited greater rates of gain in fat mass and percent body fat, increased adipocyte number, higher percentage of small adipocytes, and greater cyclin A1 mRNA in epididymal and perirenal adipose tissue. In contrast, 49- to 56-day-old rats had no change in most of the same characteristics. There was no increase in inflammatory mRNA expression in either cohort with WL. These findings suggest that adipose tissue in 70- to 77-day-old rats is more protected from WL than 49- to 56-day-old rats and responds by expansion via hyperplasia. PMID:24089381

  19. Earth resources-regional transfer activity contracts review

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  20. Geomagnetic sudden impulses and storm sudden commencements - A note on terminology

    NASA Technical Reports Server (NTRS)

    Joselyn, J. A.; Tsurutani, B. T.

    1990-01-01

    The definitions of and distinctions between storm sudden commencements (SSCs) and geomagnetic sudden impulses (SIs) are examined and present definitions of SIs and SSCs are modernized. Quantitative definitions of the two terms are recommended.

  1. Geomagnetic sudden impulses and storm sudden commencements - A note on terminology

    SciTech Connect

    Joselyn, J.A.; Tsurutani, B.T. JPL, Pasadena, CA )

    1990-11-01

    The definitions of and distinctions between storm sudden commencements (SSCs) and geomagnetic sudden impulses (SIs) are examined and present definitions of SIs and SSCs are modernized. Quantitative definitions of the two terms are recommended. 45 refs.

  2. Differential Magnetic Field Shear in an Active Region

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Avanesyan, M.

    2004-05-01

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

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  5. TWO-DIMENSIONAL CELLULAR AUTOMATON MODEL FOR THE EVOLUTION OF ACTIVE REGION CORONAL PLASMAS

    SciTech Connect

    López Fuentes, Marcelo; Klimchuk, James A.

    2015-02-01

    We study a two-dimensional cellular automaton (CA) model for the evolution of coronal loop plasmas. The model is based on the idea that coronal loops are made of elementary magnetic strands that are tangled and stressed by the displacement of their footpoints by photospheric motions. The magnetic stress accumulated between neighbor strands is released in sudden reconnection events or nanoflares that heat the plasma. We combine the CA model with the Enthalpy Based Thermal Evolution of Loops model to compute the response of the plasma to the heating events. Using the known response of the X-Ray Telescope on board Hinode, we also obtain synthetic data. The model obeys easy-to-understand scaling laws relating the output (nanoflare energy, temperature, density, intensity) to the input parameters (field strength, strand length, critical misalignment angle). The nanoflares have a power-law distribution with a universal slope of –2.5, independent of the input parameters. The repetition frequency of nanoflares, expressed in terms of the plasma cooling time, increases with strand length. We discuss the implications of our results for the problem of heating and evolution of active region coronal plasmas.

  6. WAITING TIMES OF QUASI-HOMOLOGOUS CORONAL MASS EJECTIONS FROM SUPER ACTIVE REGIONS

    SciTech Connect

    Wang Yuming; Liu Lijuan; Shen Chenglong; Liu Rui; Ye Pinzhong; Wang, S.

    2013-02-01

    Why and how do some active regions (ARs) frequently produce coronal mass ejections (CMEs)? These are key questions for deepening our understanding of the mechanisms and processes of energy accumulation and sudden release in ARs and for improving our space weather prediction capability. Although some case studies have been performed, these questions are still far from fully answered. These issues are now being addressed statistically through an investigation of the waiting times of quasi-homologous CMEs from super ARs in solar cycle 23. It is found that the waiting times of quasi-homologous CMEs have a two-component distribution with a separation at about 18 hr. The first component is a Gaussian-like distribution with a peak at about 7 hr, which indicates a tight physical connection between these quasi-homologous CMEs. The likelihood of two or more occurrences of CMEs faster than 1200 km s{sup -1} from the same AR within 18 hr is about 20%. Furthermore, the correlation analysis among CME waiting times, CME speeds, and CME occurrence rates reveals that these quantities are independent of each other, suggesting that the perturbation by preceding CMEs rather than free energy input is the direct cause of quasi-homologous CMEs. The peak waiting time of 7 hr probably characterizes the timescale of the growth of the instabilities triggered by preceding CMEs. This study uncovers some clues from a statistical perspective for us to understand quasi-homologous CMEs as well as CME-rich ARs.

  7. Two-dimensional Cellular Automaton Model for the Evolution of Active Region Coronal Plasmas

    NASA Astrophysics Data System (ADS)

    López Fuentes, Marcelo; Klimchuk, James A.

    2015-02-01

    We study a two-dimensional cellular automaton (CA) model for the evolution of coronal loop plasmas. The model is based on the idea that coronal loops are made of elementary magnetic strands that are tangled and stressed by the displacement of their footpoints by photospheric motions. The magnetic stress accumulated between neighbor strands is released in sudden reconnection events or nanoflares that heat the plasma. We combine the CA model with the Enthalpy Based Thermal Evolution of Loops model to compute the response of the plasma to the heating events. Using the known response of the X-Ray Telescope on board Hinode, we also obtain synthetic data. The model obeys easy-to-understand scaling laws relating the output (nanoflare energy, temperature, density, intensity) to the input parameters (field strength, strand length, critical misalignment angle). The nanoflares have a power-law distribution with a universal slope of -2.5, independent of the input parameters. The repetition frequency of nanoflares, expressed in terms of the plasma cooling time, increases with strand length. We discuss the implications of our results for the problem of heating and evolution of active region coronal plasmas.

  8. EVIDENCE OF IMPULSIVE HEATING IN ACTIVE REGION CORE LOOPS

    SciTech Connect

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

    2010-11-01

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

  9. Athletes at Risk for Sudden Cardiac Death

    ERIC Educational Resources Information Center

    Subasic, Kim

    2010-01-01

    High school athletes represent the largest group of individuals affected by sudden cardiac death, with an estimated incidence of once or twice per week. Structural cardiovascular abnormalities are the most frequent cause of sudden cardiac death. Athletes participating in basketball, football, track, soccer, baseball, and swimming were found to…

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

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  11. Sudden cardiac death in young athletes

    PubMed Central

    Östman-Smith, Ingegerd

    2011-01-01

    Athletic activity is associated with an increased risk of sudden death for individuals with some congenital or acquired heart disorders. This review considers in particular the causes of death affecting athletes below 35 years of age. In this age group the largest proportion of deaths are caused by diseases with autosomal dominant inheritance such as hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, long QT-syndrome, and Marfan’s syndrome. A policy of early cascade-screening of all first-degree relatives of patients with these disorders will therefore detect a substantial number of individuals at risk. A strictly regulated system with preparticipation screening of all athletes following a protocol pioneered in Italy, including school-age children, can also detect cases caused by sporadic new mutations and has been shown to reduce excess mortality among athletes substantially. Recommendations for screening procedure are reviewed. It is concluded that ECG screening ought to be part of preparticipation screening, but using criteria that do not cause too many false positives among athletes. One such suggested protocol will show positive in approximately 5% of screened individuals, among whom many will be screened for these diseases. On this point further research is needed to define what kind of false-positive and false-negative rate these new criteria result in. A less formal system based on cascade-screening of relatives, education of coaches about suspicious symptoms, and preparticipation questionnaires used by athletic clubs, has been associated over time with a sizeable reduction in sudden cardiac deaths among Swedish athletes, and thus appears to be worth implementing even for junior athletes not recommended for formal preparticipation screening. It is strongly argued that in families with autosomal dominant disorders the first screening of children should be carried out no later than 6 to 7 years of age. PMID:24198575

  12. Sudden Gains During Therapy of Social Phobia

    PubMed Central

    Hofmann, Stefan G.; Schulz, Stefan M.; Meuret, Alicia E.; Moscovitch, David A.; Suvak, Michael

    2007-01-01

    The present study investigated the phenomenon of sudden gains in 107 participants with social phobia (social anxiety disorder) who received either cognitive–behavioral group therapy or exposure group therapy without explicit cognitive interventions, which primarily used public speaking situations as exposure tasks. Twenty-two out of 967 session-to-session intervals met criteria for sudden gains, which most frequently occurred in Session 5. Individuals with sudden gains showed similar improvements in the 2 treatment groups. Although cognitive–behavioral therapy was associated with more cognitive changes than exposure therapy, cognitive changes did not precede sudden gains. In general, the results of this study question the clinical significance of sudden gains in social phobia treatment. PMID:16881776

  13. Lower stratospheric gravity wave activity over Gadanki (13.5°N, 79.2°E) during the stratospheric sudden warming of 2009: Link with potential vorticity intrusion near Indian sector

    NASA Astrophysics Data System (ADS)

    Nath, D.; Sridharan, S.; Sathishkumar, S.; Gurubaran, S.; Chen, W.

    2013-03-01

    The relation between intrusions of stratospheric air into the upper troposphere and deep convection at equator during the stratospheric sudden warming (SSW) event of 2009 is examined using the ERA-interim reanalysis and NOAA outgoing longwave radiation (OLR) data sets. There is an intrusion of potential vorticity (PV) equatorward and westward, when the amplitude of planetary wave of zonal wavenumber 2 at 10 hPa decreases drastically and polar stratospheric temperature increases simultaneously at 60°N. As a special case, the PV intrudes as narrow tongue at longitudes near 60°E (Indian ocean sector) even to latitudes less than 20°N during the SSW, whereas PV normally intrudes near 210°E (eastern Pacific) to equatorial latitudes. Decrease in OLR is observed east of these PV intrusions. Vertical velocity is largely upward at all pressure levels. As the PV intrusion can have profound influence on tropospheric convection and the latent heat release due to equatorial convection is an important source mechanism for the generation of gravity waves, we examined gravity wave activity in the daily radiosonde observations of winds and temperature at Gadanki (13.5°N, 79.2°E). It is observed that the potential energy per unit mass, estimated from the gravity wave temperature perturbations has considerably enhanced in relation with the deep convection. The predominant direction of propagation of the gravity waves is westward prior to the SSW, as a response to the active convection over Indonesia, turns to eastward during and after the SSW, as a response to the PV intrusion induced convection over west of India.

  14. Genetics of sudden cardiac death.

    PubMed

    Refaat, Marwan M; Hotait, Mostafa; London, Barry

    2015-07-01

    Sudden cardiac death (SCD) is defined by the World Health Organization (WHO) as death within 1 h of symptom onset (witnessed) or within 24 h of being observed alive and symptom free (unwitnessed). It affects more than 3 million people annually worldwide and affects approximately 1/1000 people each year in the USA. Familial studies of syndromes with Mendelian inheritance, candidate genes analyses, and genome-wide association studies (GWAS) have helped our understanding of the genetics of SCD. We will review the genetics of arrhythmogenic hereditary syndromes with Mendelian inheritance from familial studies with structural heart disease (hypertrophic cardiomyopathy, dilated cardiomyopathy, and arrhythmogenic cardiomyopathy) as well as primary electrical causes (long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, and short QT syndrome). In addition, we will review the genetics of intermediate phenotypes for SCD such as coronary artery disease and electrocardiographic variables (QT interval, QRS duration, and RR interval). Finally, we will review rare and common variants that are associated with SCD in the general population and were identified from candidate gene analyses and GWAS. Our understanding of the genetics of SCD will improve by the use of next-generation sequencing/whole-exome sequencing as well as whole-genome sequencing which have the potential to discover unsuspected common and rare genetic variants that might be associated with SCD. PMID:26026997

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  17. Study of Quasi-Homologous Coronal Mass Ejections from Super Active Regions in Solar Cycle 23

    NASA Astrophysics Data System (ADS)

    Liu, L.; Wang, Y.; Shen, C.; Liu, R.; Ye, P.; Wang, S.

    2014-12-01

    Coronal Mass Ejections are most severe eruptive phenomenon in the solar atmosphere and are believed as the major energy source of the Near-Earth Space Environment. The study of CMEs is very important for the Space Weather forecast. The active regions , especially super-active regions, containing lots of magnetic free energy, are considered as the most important source regions of CMEs. Knowing why and how may some active regions (ARs) frequently produce CMEs is one of the key questions to deepen our understanding of the mechanisms and processes of energy accumulation and sudden release in ARs as well as improving our capability of space weather prediction. Based on above, we have done two parts of work: the first one is selecting all 37 SARs in the entire 23 solar cycle, using data provided by SOHO/LASCO C2|EIT|MDI, manually determining 285 CMEs produced by those SARs; second, we use the term 'quasi-homologous'to refer to successive CMEs originating from the same ARs within a short interval, analyze the rules of quasi-homologous CMEs' generation. Finally, we got two conclusions. 1. The waiting times of quasi-homologous CMEs have a two-component distribution with a separation at about 18 hours. The first component is a Gaussian-like distribution with a peak at about 7 hours, which indicates a tight physical connection between these quasi-homologous CMEs. The likelihood of occurrences of two or more CMEs faster than 1200 km /s from the same AR within 18 hours is about 20%. 2. The correlation analysis among CME waiting times, CME speeds and CME occurrence rates reveals that these quantities are independent to each other, suggesting that the perturbation by preceding CMEs rather than free energy input be the direct cause of quasi-homologous CMEs. The peak waiting time of 7 hours probably characterize the time scale of the growth of instabilities triggered by preceding CMEs. This study uncovers more clues from a statistical perspective for us to understand quasi

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  1. Socioeconomic and regional differences in active transportation in Brazil

    PubMed Central

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

    2016-01-01

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

  2. [Sudden deafness and the craniocervical transition].

    PubMed

    Hörmann, K; Weh, L; Fritz, W; Borner, U

    1989-08-01

    Morphological alterations of the cranio-cervical junction as a basilar impression, a ponticulus posterior, an atlas assimilation, an intervertebral narrowing, and spondylosis deformans were found radiologically. There was no difference to a healthy population. This means there are no correlations between static morphological changes of the craniocervical junction and sudden deafness. However, there was a statistically significant reduced mobility in the upper cervical spine in patients suffering from sudden deafness. Especially very high standard deviations in the atlanto-occipital and the atlanto-dental joint are interpreted as hypermobile as well hypomobile atlas joints. These results indicate a correlation between sudden deafness and functional pathology of the craniocervical junction. PMID:2789574

  3. The Historical Perspective of Athletic Sudden Death.

    PubMed

    Hoyt, Walter J; Dean, Peter N; Battle, Robert W

    2015-07-01

    Since antiquity, the athlete has been elevated to a heroic status both within small communities and at the international level. Although numerous population studies have estimated athletic sudden death to be a rare event, the consequences resonate far beyond those directly affected. Sports cardiology has evolved as a result of these tragedies, which highlighted a need for safer play and more programmatic protection of the athlete in play. In this article, athletic sudden death is analyzed from a historical and literary perspective and the development of modern initiatives to protect athletes from sudden death is reviewed. PMID:26100429

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

    ERIC Educational Resources Information Center

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

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

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

    NASA Technical Reports Server (NTRS)

    Schatten, Kenneth H.

    1990-01-01

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

  6. SNS Devices With Pinhole-Defined Active Regions

    NASA Technical Reports Server (NTRS)

    Hunt, Brian D.; Barner, Jeffrey B.

    1996-01-01

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

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

    PubMed Central

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

    2016-01-01

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

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

    ERIC Educational Resources Information Center

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

    2005-01-01

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

  9. Unwinding motion of a twisted active region filament

    SciTech Connect

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

    2014-12-10

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

  10. Inferred flows of electric currents in solar active regions

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Tripathi, Durgesh

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

  12. Evolution of two Flaring Active Regions With CME Association

    NASA Astrophysics Data System (ADS)

    Thalmann, J. K.; Wiegelmann, T.

    2008-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  14. Altered Contralateral Auditory Cortical Morphology in Unilateral Sudden Sensorineural Hearing Loss

    PubMed Central

    Fan, Wenliang; Zhang, Wenjuan; Li, Jing; Zhao, Xueyan; Mella, Grace; Lei, Ping; Liu, Yuan; Wang, Haha; Cheng, Huamao; Shi, Hong; Xu, Haibo

    2015-01-01

    Objective: To investigate the cerebral gray matter volume alterations in unilateral sudden sensorineural hearing loss patients within the acute period by the voxel-based morphometry method, and to determine if hearing impairment is associated with regional gray matter alterations in unilateral sudden sensorineural hearing loss patients. Study Design: Prospective case study. Setting: Tertiary class A teaching hospital. Patients: Thirty-nine patients with left-side unilateral sudden sensorineural hearing loss and 47 patients with right-side unilateral sudden sensorineural hearing loss. Intervention: Diagnostic. Main Outcome Measure: To compare the regional gray matter of unilateral sudden sensorineural hearing loss patients and healthy control participants. Results: Compared with control groups, patients with left side unilateral sudden sensorineural hearing loss had significant gray matter reductions in the right middle temporal gyrus and right superior temporal gyrus, whereas patients with right side unilateral sudden sensorineural hearing loss showed gray matter decreases in the left superior temporal gyrus and left middle temporal gyrus. A significant negative correlation with the duration of the sudden sensorineural hearing loss (R = −0.427, p = 0.012 for left-side unilateral SSNHL and R = −0.412, p = 0.013 for right-side unilateral SSNHL) was also found in these brain areas. There was no region with increased gray matter found in both groups of unilateral sudden sensorineural hearing loss patients. Conclusions: This study confirms that detectable decreased contralateral auditory cortical morphological changes have occurred in unilateral SSNHL patients within the acute period by voxel-based morphometry methods. The gray matter volumes of these brain areas also perform a negative correlation with the duration of the disease, which suggests a gradual brain structural impairment after the progression of the disease. PMID:26595717

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

    NASA Astrophysics Data System (ADS)

    Bradshaw, Stephen; Viall, Nicholeen

    2016-05-01

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

  16. Respiratory drive during sudden cold water immersion.

    PubMed

    Mekjavić, I B; La Prairie, A; Burke, W; Lindborg, B

    1987-10-01

    Sudden decreases in cutaneous temperature induce an immediate ventilatory response, which has been termed the inspiratory or 'gasp' reflex. This respiratory response has been implicated as a contributing factor to cold water immersion drowning. In the present study, five subjects wearing either shorts or a variety of thermal protective apparel were immersed on separate occasions in 10 degrees C water. The observed peak mean skin temperature cooling rates (dTs/dt) for the different conditions varied from 6.9 +/- 2.1 degrees C/min for the shorts condition to 1.8 +/- 0.3 degrees C/min for a helicopter pilot suit made of cotton ventile material. During the immersion, recordings were made of respiratory drive, as indicated by the mouth occlusion pressure at 100 msec following the onset of inspiration (P0.1). The respiratory drive, an indicator of central inspiratory activity, correlated well with peak dTs/dt. The slope P0.1/(dTs/dt) was subject dependent and did not appear to be related to body composition. The substantial intersubject variability in the respiratory response is suggested to result from differences in the central integration of thermoafferent information. It is concluded that the inspiratory reflex is the result of cutaneous thermoreceptor activity. PMID:3659607

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

    PubMed

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

    2011-01-01

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

  18. Surviving the Sudden Death of a Baby

    MedlinePlus

    ... Funds Request Information Get Involved Surviving the Sudden Death of a Baby Home Grieving Families Surviving the ... Candle on For Families Who Have Experienced the Death of a Baby The numbers are staggering. Every ...

  19. Sudden death in hemodialysis: an update.

    PubMed

    Kanbay, Mehmet; Afsar, Baris; Goldsmith, David; Covic, Adrian

    2010-01-01

    Cardiovascular disease including sudden death, myocardial infarction, cardiac arrest, malignant arrhythmias and other cardiac causes is the major cause of death accounting for 43% of all-cause mortality among hemodialysis patients. In addition to increased traditional risk factors, hemodialysis patients also have a number of nontraditional cardiovascular risk factors, which may play a prominent role in the development of sudden death such as left ventricular hypertrophy, coronary artery disease, rapid electrolyte shifts, QT dispersion, sympathetic overactivity, calcium-phosphate deposition. The purpose of the present review was to critically review the current literature to summarize the following aspects: (1) the pathophysiological mechanism responsible for sudden death in hemodialysis patients, and (2) the prevention and management of sudden death in hemodialysis patients. PMID:20798493

  20. Sudden deaths in yearling feedlot cattle.

    PubMed

    Pierson, R E; Jensen, R; Lauerman, L H; Saari, D A; Braddy, P M; McChesney, A E; Horton, D P

    1976-09-01

    A survey of the causes for fatal diseases of yearling feedlot cattle was conducted on more than 407,000 cattle during a 14-month period. Of the 4,260 (1%) cattle that died during this period, 1,358 (32%) were categorized as cases of "sudden death syndrome." Of the 11 most frequent causes of the syndrome, as determined at necropsy, only 4--bloat, pulmonary aneurysms, riding injury, and hemopericardium--were considered as short-course problems and true causes of sudden death. The largest number of cases of sudden death were attributed to pneumonia (113 animals). Consequently, the sudden death syndrome is a misnomer for many long-course diseases and, in some instances, a mask for neglect because, as clinically used, the name frequently includes cattle that have been sick, often with pneumonia, for several days. PMID:956032

  1. Sudden cardiac death in the older athlete.

    PubMed

    Chugh, Sumeet S; Weiss, Joseph B

    2015-02-10

    The overwhelming majority of sports-related sudden deaths occur among those older than 35 years of age. Because increasing numbers of older people are participating in organized endurance and competitive sporting events, the incidence of sports-related sudden death in older adults is expected to rise. Older athletes will approach clinical cardiologists for advice regarding their fitness for participation. It is important to recognize both that strenuous exercise is associated with a transient elevation in risk of sudden cardiac death and that appropriate training substantially reduces this risk. The approach to pre-participation screening for risk of sudden death in the older athlete is a complex issue and at present is largely focused on identifying inducible ischemia due to significant coronary disease. In this brief review, we summarize the current state of knowledge in this area with respect to epidemiology, mechanisms, and approaches to risk stratification, as viewed from the perspective of the consulting clinical cardiologist. PMID:25660928

  2. THE EVOLUTION OF DARK CANOPIES AROUND ACTIVE REGIONS

    SciTech Connect

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

    2011-05-20

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  4. Sudden cardiac death in 2 young siblings.

    PubMed

    Kundu, Reetu; Punia, Rajpal Singh; Handa, Uma; Singh, Amandeep; Mohan, Harsh

    2014-12-01

    Hypertrophic cardiomyopathy is a disease known for exhibiting phenotypic and genetic heterogeneity. At times, sudden cardiac death may be the first and foremost manifestation of the disease. We report 2 cases of hypertrophic cardiomyopathy causing sudden death, which were diagnosed on autopsy with special emphasis on histopathological findings of this entity. The role of a pathologist cannot be undermined as the disease is a diagnostic challenge often overlooked by the neophytes in the field due to unawareness. PMID:25361060

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

    NASA Technical Reports Server (NTRS)

    Cannon, Anne T.; Marquette, William H.

    1991-01-01

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

  6. Extreme storm activity in North Atlantic and European region

    NASA Astrophysics Data System (ADS)

    Vyazilova, N.

    2010-09-01

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

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

    NASA Astrophysics Data System (ADS)

    Mickaelian, A.

    2015-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  9. [Sudden cardiac death in diabetes mellitus].

    PubMed

    Israel, C W; Lee-Barkey, Y H

    2016-05-01

    Sudden cardiac death (SCD) represents one of the most frequent causes of death in patients with diabetes. In contrast to patients without diabetes it has not been significantly reduced despite improvements in the treatment of acute myocardial infarction and long-term treatment of cardiovascular diseases as well as diabetes mellitus. Several mechanisms can be responsible for the high incidence of SCD in diabetics: 1. arrhythmogenic effects mediated via cardiac autonomic neuropathy, repolarization disturbances or sympathetic tone activation (hypoglycemia), 2. myocardial ischemia due to atherosclerosis, endothelial dysfunction, platelet aggregation or thrombophilic effects, 3. myocardial disease due to inflammation, fibrosis, associated hypertension or uremia and 4. potassium imbalance due to diabetic nephropathy or hypoglycemia. This review introduces concepts of mechanisms that are responsible for SCD in patients with diabetes. Treatment of patients with diabetes should primarily consider a systematic assessment of any deterioration of this chronic disease and of complications at an early stage. Cardiovascular drug treatment corresponds to that of non-diabetics. In antidiabetic treatment drugs with a low risk of hypoglycemia should be preferred. Treatment with implantable cardioverter defibrillators (ICD) also combined with cardiac resynchronization therapy () demonstrated a high life-saving potential particularly in patients with diabetes. PMID:27071967

  10. Predicting the risk of sudden cardiac death.

    PubMed

    Lerma, Claudia; Glass, Leon

    2016-05-01

    Sudden cardiac death (SCD) is the result of a change of cardiac activity from normal (typically sinus) rhythm to a rhythm that does not pump adequate blood to the brain. The most common rhythms leading to SCD are ventricular tachycardia (VT) or ventricular fibrillation (VF). These result from an accelerated ventricular pacemaker or ventricular reentrant waves. Despite significant efforts to develop accurate predictors for the risk of SCD, current methods for risk stratification still need to be improved. In this article we briefly review current approaches to risk stratification. Then we discuss the mathematical basis for dynamical transitions (called bifurcations) that may lead to VT and VF. One mechanism for transition to VT or VF involves a perturbation by a premature ventricular complex (PVC) during sinus rhythm. We describe the main mechanisms of PVCs (reentry, independent pacemakers and abnormal depolarizations). An emerging approach to risk stratification for SCD involves the development of individualized dynamical models of a patient based on measured anatomy and physiology. Careful analysis and modelling of dynamics of ventricular arrhythmia on an individual basis will be essential in order to improve risk stratification for SCD and to lay a foundation for personalized (precision) medicine in cardiology. PMID:26660287

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  13. Fine structure of the magnetic field in active regions

    NASA Astrophysics Data System (ADS)

    Pustilnik, Lev; Beskrovnaya, Nina; Ikhsanov, Nazar

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

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  16. Simulation of Active-Region-Scale Flux Emergence

    NASA Astrophysics Data System (ADS)

    Manchester, W.; van der Holst, B.

    2015-12-01

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

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

    PubMed

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

    2015-01-01

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

  18. Gravity waves in the thermosphere during a sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Yigit, E.; Medvedev, A. S.

    2012-12-01

    For the first time, the propagation and dissipation of internal gravity waves (GWs) of lower atmospheric origin to the thermosphere above the turbopause (~105 km) during a sudden stratospheric warming (SSW) are examined. The study is performed with a general circulation model (GCM) coupling the lower atmosphere with the thermosphere and the implemented spectral nonlinear extended GW parameterization of Yigit et al. (2008). The Yigit et al. (2008) extended GW parameterization calculates the propagation and dissipation of small-scale GWs in the whole atmosphere system by physically taking into account ion drag, molecular viscosity and thermal conduction, eddy viscosity, nonlinear diffusion, and radiative damping in form of Newtonian cooling. Model simulations reveal a strong modulation by SSWs of GW activity, momentum deposition rates, and the circulation feedbacks at heights up to F region altitudes (~270 km). Wave-induced root mean square wind fluctuations increase several times during the warming in the thermosphere above the turbopause. This occurs mainly due to a reduction of filtering eastward traveling GWs by the weaker stratospheric jet. These waves propagate higher under the favorable conditions, grow in amplitude, and produce stronger forcing on the mean flow, compared to pre-warming period, when they are dissipated in the thermosphere. The evolution of stratospheric and mesospheric winds during an SSW life-cycle creates a robust and distinctive response in GW activity and mean fields deeply in the thermosphere. Yigit, E., A.~D. Aylward, and A.~S. Medvedev (2008), Parameterization of the effects of vertically propagating gravity waves for thermosphere general circulation models: Sensitivity study, J. Geophys. Res., 113, D19106, doi:10.1029/2008JD010135.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  20. Behavior of chickens prior to death from sudden death syndrome.

    PubMed

    Newberry, R C; Gardiner, E E; Hunt, J R

    1987-09-01

    A study was made to determine if chickens dying from sudden death syndrome (SDS) showed any unusual behavioral characteristics during the final 12 h preceding death. Continuous video recordings were made of floor pens of 50 to 120 individually marked male broiler chickens between 3 and 10 wk of age. Behavioral data were obtained from video tapes played back following death of chickens from SDS. Analysis of the video tapes revealed no significant differences between 10 SDS chickens and their matched controls in the frequencies or proportions of time spent in each of 19 different behavioral activities. All SDS chickens exhibited a sudden attack prior to death lasting an average of 53 s and characterized by loss of balance, violent flapping, and strong muscular contractions. There was no evidence that death was preceded by a particular environmental or behavioral event. It was concluded that there were no consistent behavioral symptoms which could be used to identify SDS chickens prior to death. PMID:3684869

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

    NASA Astrophysics Data System (ADS)

    Florescu, Gabriela; Feurdean, Angelica

    2015-04-01

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

  2. Monitoring rice farming activities in the Mekong Delta region

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    SciTech Connect

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

    2010-05-10

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

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

    SciTech Connect

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

    2014-05-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  7. Ancient Tectonic and Volcanic Activity in the Tharsis Region

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  9. Sudden Unexpected Postnatal Collapse of the Newborn.

    PubMed

    Ferrarello, Debi; Carmichael, Tanya

    2016-01-01

    Sudden unexpected postnatal collapse is a rare but devastating neonatal event. A well-appearing, full-term newborn with Agpar scores of eight or more suddenly crashes, often with full respiratory and cardiac arrest. Up to half of newborns with sudden unexpected postnatal collapse die, with many survivors suffering serious neurological damage. The first 2 hours of life are the hours of greatest risk, coinciding with the time frame when nurses encourage breastfeeding and uninterrupted skin-to-skin contact between women and newborns. Nursing assessments and measures to promote neonates' optimal transition to extrauterine life through skin-to-skin contact and early breastfeeding while decreasing the risk of this catastrophic event are described. Nursing surveillance to promote optimal transition in a safe environment is essential, and birth facilities should allocate staffing resources accordingly. PMID:27287353

  10. Sudden death in Lesch-Nyhan disease

    PubMed Central

    Neychev, Vladimir Kostadinov; Jinnah, H A

    2012-01-01

    To increase awareness of sudden and unexpected death in Lesch-Nyhan disease (LND) and to explore its potential causes, we report the anteceding clinical features and laboratory evaluations of five males with LND who ultimately experienced sudden and unexpected death, along with three additional males who suffered serious respiratory events during life. The ages of patients ranged from 2 to 45 years. The cause of sudden death in LND appears to have a respiratory rather than a cardiogenic basis. All cases cannot be linked readily with a single respiratory process. Instead, different respiratory processes appear to operate in different cases. These may include aspiration, laryngospasm, central apnea, cyanotic breath-holding spells, and high cervical spine damage. Better recognition of these processes will help to guide appropriate workup and management that could include chest imaging, endoscopy of the airways, polysomnography, electroencephalogram, and brain and/or spine imaging. PMID:17044962

  11. Sudden vanishing of spin squeezing under decoherence

    SciTech Connect

    Wang Xiaoguang; Miranowicz, Adam; Liu, Yu-xi; Sun, C. P.; Nori, Franco

    2010-02-15

    In order to witness multipartite correlations beyond pairwise entanglement, spin-squeezing parameters are analytically calculated for a spin ensemble in a collective initial state under three different decoherence channels. It is shown that, in analogy to pairwise entanglement, the spin squeezing described by different parameters can suddenly become zero at different vanishing times. This finding shows the general occurrence of sudden vanishing phenomena of quantum correlations in many-body systems, which here is referred to as spin-squeezing sudden death (SSSD). It is shown that the SSSD usually occurs due to decoherence and that SSSD never occurs for some initial states in the amplitude-damping channel. We also analytically obtain the vanishing times of spin squeezing.

  12. Statistical analysis of sudden chemical leakage accidents reported in China between 2006 and 2011.

    PubMed

    Li, Yang; Ping, Hua; Ma, Zhi-Hong; Pan, Li-Gang

    2014-04-01

    According to the data from authoritative sources, 1,400 sudden leakage accidents occurred in China during 2006 to 2011 were investigated, in which, 666 accidents were used for statistical characteristic abstracted with no or little damage. The research results were as follows: (1) Time fluctuation: the yearly number of sudden leakage accidents is shown to be decreasing from 2006 to 2010, and a slightly increase in 2011. Sudden leakage accidents occur mainly in summer, and more than half of the accidents occur from May to September. (2) Regional distribution: the accidents are highly concentrated in the coastal area, in which accidents result from small and medium-sized enterprises more easily than that of the larger ones. (3) Pollutants: hazardous chemicals are up to 95 % of sudden leakage accidents. (4) Steps: transportation represents almost half of the accidents, followed by production, usage, storage, and discard. (5) Pollution and casualties: it is easy to cause environmental pollution and casualties. (6) Causes: more than half of the cases were caused by human factor, followed by management reason, and equipment failure. However, sudden chemical leakage may also be caused by high temperature, rain, wet road, and terrain. (7) The results of principal component analysis: five factors are extracted by the principal component analysis, including pollution, casualties, regional distribution, steps, and month. According to the analysis of the accident, the characteristics, causes, and damages of the sudden leakage accident will be investigated. Therefore, advices for prevention and rescue should be acquired. PMID:24407779

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    SciTech Connect

    Morgan, Huw; Jeska, Lauren; Leonard, Drew

    2013-06-01

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

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

    USGS Publications Warehouse

    Thatcher, W.; Pollitz, F.F.

    2008-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  19. C IV Doppler shifts observed in active region filaments

    NASA Technical Reports Server (NTRS)

    Klimchuk, J. A.

    1986-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

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

    SciTech Connect

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

    2014-04-28

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

  2. Sudden perturbation approximations for interaction of atoms with intense ultrashort electromagnetic pulses

    NASA Astrophysics Data System (ADS)

    Lugovskoy, Andrey; Bray, Igor

    2015-12-01

    The response of an atom to the action of a pulse shorter than the Kepler period of the optically-active electron is often treated analytically using the sudden-perturbation approximation (SPA). It relies on the truncation of the evolution operator expansion in a series over the dimensionless parameter ɛ sys τ L, where ɛ sys is the system-dependent characteristic energy and τ L is the pulse duration. We examine the SPA with the use of a basis-based solution of the time-dependent Schrödinger equation (TDSE) for the case of a hydrogen atom interacting with two different types of ultrashort pulses, a half-cycle pulse and a few-cycle pulse. The length-gauge form of the electron-field interaction potential is used. The SPA transition probabilities are shown to deviate slightly but systematically from the correct values for the positive-energy states in the region where the sudden-perturbation condition is violated. It is shown that the SPA expectation value of the electron displacement as a function of time differ qualitatively from what follows from the ab initio TDSE solution. Nevertheless, the SPA is shown to be a good approximation for the description of the expectation value of the electron momentum.

  3. Sudden cardiac death – Historical perspectives

    PubMed Central

    Abhilash, S.P.; Namboodiri, Narayanan

    2014-01-01

    Sudden cardiac death (SCD) is an unexpected death due to cardiac causes that occurs in a short time period (generally within 1 h of symptom onset) in a person with known or unknown cardiac disease. It is believed to be involved in nearly a quarter of human deaths, with ventricular fibrillation being the most common mechanism. It is estimated that more than 7 million lives per year are lost to SCD worldwide. Historical perspectives of SCD are analyzed with a brief description on how the developments in the management of sudden cardiac arrest evolved over time. PMID:24568828

  4. Aborted sudden cardiac death: a clinical perspective

    PubMed Central

    Mazeika, P

    2001-01-01

    Sudden cardiac death in the community remains a major public health problem. The purpose of this article is to outline the epidemiology, pathophysiology, and immediate treatment of the cardiac arrest victim. The subsequent in-hospital diagnostic evaluation and management will then be discussed with an emphasis on the role of the implantable cardioverter-defibrillator. A systematic and evidence based approach should help to optimize patient care.


Keywords: cardiology; implantable cardioverter-defibrillator; resuscitation; sudden cardiac death PMID:11375448

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

    PubMed

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

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  8. Chemical Fingerprints of Star Forming Regions and Active Galaxies

    NASA Astrophysics Data System (ADS)

    Pérez-Beaupuits, Juan-Pablo

    2010-10-01

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

  9. Behaviour of oscillations in loop structures above active regions

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  10. Sudden stretching of a four layered composite plate

    NASA Technical Reports Server (NTRS)

    Sih, G. C.; Chen, E. P.

    1980-01-01

    An approximate theory of laminated plates is developed by assuming that the extensioral and thickness mode of vibration are coupled. The mixed boundary value crack problem of a four layered composite plate is solved. Dynamic stress intensity factors for a crack subjected to suddenly applied stress are found to vary as a function of time and depend on the material properties of the laminate. Stress intensification in the region near the crack front can be reduced by having the shear modulus of the inner layers to be larger than that of the outer layers.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  12. Active Region Filaments Might Harbor Weak Magnetic Fields

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Philip, Judge

    2013-07-01

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

  14. High power VCSEL device with periodic gain active region

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  16. Successive Impacts Of The Earth by Several Halo CMEs From Active Region NOAA 652

    NASA Astrophysics Data System (ADS)

    Yousef, Shahinaz; El Nawawy, M. S.; El-Nazer, M.; Yousef, Mohamed

    Several Halo CMEs hit the Earth in the second half of July 2004. They were produced by the very large complex active region NOAA 652 (Yousef et al. 2005). For CME details consult the web (ftp://lasco6.nascom.nasa.gov/pub/lasco/status/LASCO_CME_List_004).

    We focus on the 26th -27th of July CME hit. This CME was associated with the long-duration M1 flare at 25/15:14. It made a very fast Sun to Earth transit-just over 31 hours (SGAS 27 July 2004). A greater than 10 MeV proton event began at 25/18:55. Solar wind speed remained elevated from 500 to over 700 km/s. A Severe Geomagnetic storm was observed and the aurora was seen as far as California.

    A strong shock impacted the ACE spacecraft at 26/22:28. A sudden impulse (SI) of 96 nT was observed on the Boulder magnetometer at 22:51. The IMF Bz component was turned negative (-18 nT). Generally speaking, according to de Pater and Lissauer (2001), since a strong CME disturbance in the solar wind is usually preceded by an interplanetary shock followed by an enhanced density and velocity, the field strength first increases when the disturbance hits the magnetosphere, inducing an increase in the ring current. Several hours(up to over 25 hrs) the field strength Dst decreases dramatically during the storm main phase which typically lasts for a day The main phase is caused by an increase in the ring current, resulting from an enhanced particle flow towards the Earth. It is well known that geomagnetic storms tend to occur when IMF is directed southward. Magnetic reconnection occurs between the negative IMF and the magnetosphere thus opens the field lines with one end connected to the Earth (Dungey 1963). This magnetic reconnection allowed the protons and electrons to leak in. The proton and electron flux maximums occurred around the time of geomagnetic storm commencement which lasted for about 27 h (fig. 1). This is in agreement with the statement of Robinson (2003) that large numbers of energetic protons are

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

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  18. CHP REGIONAL APPLICATION CENTERS: ACTIVITIES AND SELECTED RESULTS

    SciTech Connect

    Schweitzer, Martin

    2010-08-01

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

  19. [Sudden death. Role of the electrophysiologic study].

    PubMed

    Colín Lizalde, Luis

    2002-01-01

    At present, sudden death is considered a major health problem, DeBoer in 1935, recognized the clinical importance of ventricular fibrillation as the cause of sudden cardiac death. Sudden death due to cardiovascular problems has been established as one of the main causes of death in the developed countries and in developing countries as ours, where the deaths caused by cardiovascular diseases represent 15% of the total, exceeding other causes of death. The frequency of sudden death in our country is unknown, but more frequently we hear about cases of patients that have been reanimated for cardiac arrest; in the United States of America the frequency has been estimated between 400,000 at 500,000 per year although, recently, 250,000 at 300,000 events are being mentioned. It is convenient to comment that the causal arrhythmias are diverse and may vary depending on the underlying disease, although, generally, it can be pointed out that 80% of them are due to tachyarrhythmias. It's important to point out that there is a strong relationship between left ventricular dysfunction, the frequency of ventricular arrhythmias, and fatal cardiac events due to cardiac rhythm disturbances. The recommendations for electrophysiological studies are: 1) patients surviving cardiac arrest, occurring without evidence of an acute Q-wave myocardial infarction and 2) patients surviving cardiac arrest occurring more than 48 hours after the acute phase of myocardial infarction in the absence of a recurrent ischemic event. PMID:12001869

  20. Sudden Viscous Dissipation of Compressing Turbulence

    NASA Astrophysics Data System (ADS)

    Davidovits, Seth; Fisch, Nathaniel J.

    2016-03-01

    Compression of turbulent plasma can amplify the turbulent kinetic energy, if the compression is fast compared to the viscous dissipation time of the turbulent eddies. A sudden viscous dissipation mechanism is demonstrated, whereby this amplified turbulent kinetic energy is rapidly converted into thermal energy, suggesting a new paradigm for fast ignition inertial fusion.

  1. Sudden Viscous Dissipation of Compressing Turbulence.

    PubMed

    Davidovits, Seth; Fisch, Nathaniel J

    2016-03-11

    Compression of turbulent plasma can amplify the turbulent kinetic energy, if the compression is fast compared to the viscous dissipation time of the turbulent eddies. A sudden viscous dissipation mechanism is demonstrated, whereby this amplified turbulent kinetic energy is rapidly converted into thermal energy, suggesting a new paradigm for fast ignition inertial fusion. PMID:27015488

  2. When My Name Suddenly Was "Murphy"

    NASA Technical Reports Server (NTRS)

    Mitchell, David

    2002-01-01

    The author recounts how he was named the Launch Vehicle Manager for the Mars Pathfinder mission, after his project manager suffered a heart attack shortly before launch. He explains that he was prepared for the sudden responsibilities, since his project manager required that he learn many new skills.

  3. Sudden Viscous Dissipation of Compressing Turbulence

    DOE PAGESBeta

    Davidovits, Seth; Fisch, Nathaniel J.

    2016-03-11

    Here we report compression of turbulent plasma can amplify the turbulent kinetic energy, if the compression is fast compared to the viscous dissipation time of the turbulent eddies. A sudden viscous dissipation mechanism is demonstrated, whereby this amplified turbulent kinetic energy is rapidly converted into thermal energy, suggesting a new paradigm for fast ignition inertial fusion.

  4. Sudden Gains during Therapy of Social Phobia

    ERIC Educational Resources Information Center

    Hofmann, Stefan G.; Schultz, Stefan M.; Meuret, Alicia E.; Moscovitch, David A.; Suvak, Michael

    2006-01-01

    The present study investigated the phenomenon of sudden gains in 107 participants with social phobia (social anxiety disorder) who received either cognitive-behavioral group therapy or exposure group therapy without explicit cognitive interventions, which primarily used public speaking situations as exposure tasks. Twenty-two out of 967…

  5. Alcohol Use and Sudden Infant Death Syndrome

    ERIC Educational Resources Information Center

    Friend, Karen B.; Goodwin, Matthew S.; Lipsitt, Lewis P.

    2004-01-01

    Despite general evidence of fetal toxicities associated with sudden infant death syndrome (SIDS), there has been limited research focusing on the effects of parental alcohol use on SIDS occurrence, either directly or in interaction with other risk conditions. The purpose of this paper is to review the literature on parental, especially maternal,…

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1998-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    EPA Science Inventory

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

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

    SciTech Connect

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

    2015-02-28

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

  11. Chromospheric magnetic fields of an active region filament

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

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

    NASA Technical Reports Server (NTRS)

    Holman, Gordon D.

    1992-01-01

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

  13. Sudden Unexpected Infant Death and Sudden Infant Death Syndrome: Reducing the Risk

    MedlinePlus

    ... organizations offer support: CJ Foundation for SIDS First Candle Sudden Unexplained Death In Childhood Foundation (SUDC) The ... and Caregivers Healthy Children Safe to Sleep First Candle CJ Foundation for SIDS Cribs for Kids Safe ...

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    SciTech Connect

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

    2012-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  17. Regional Triggering of Volcanic Activity Following Large Magnitude Earthquakes

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  18. 77 FR 24952 - Agency Information Collection Activities; Proposed Collection; Comment Request; Regional Haze...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-26

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

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

    SciTech Connect

    McIntosh, Scott W.; Leamon, Robert J.

    2014-11-20

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

  20. Sudden Heart Death More Common in Male Minority Athletes

    MedlinePlus

    ... medlineplus.gov/news/fullstory_159606.html Sudden Heart Death More Common in Male Minority Athletes Inherited condition ... found that about one-third of sudden cardiac deaths were caused by the heart condition hypertrophic cardiomyopathy. ...

  1. Sudden Heart Death More Common in Male Minority Athletes

    MedlinePlus

    ... gov/medlineplus/news/fullstory_159606.html Sudden Heart Death More Common in Male Minority Athletes Inherited condition ... found that about one-third of sudden cardiac deaths were caused by the heart condition hypertrophic cardiomyopathy. ...

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  3. F-MARC: promoting the prevention and management of sudden cardiac arrest in football.

    PubMed

    Kramer, Efraim Benjamin; Dvorak, J; Schmied, C; Meyer, T

    2015-05-01

    Sudden cardiac death is the most common cause of unnatural death in football. To prevent and urgently manage sudden cardiac arrest on the football field-of-play, F-MARC (FIFA Medical and Research Centre) has been fully committed to a programme of research, education, standardisation and practical implementation. This strategy has detected football players at medical risk during mandatory precompetition medical assessments. Additionally, FIFA has (1) sponsored internationally accepted guidelines for the interpretation of an athlete's ECG, (2) developed field-of-play-specific protocols for the recognition, response, resuscitation and removal of a football player having sudden cardiac arrest and (3) introduced and distributed the FIFA medical emergency bag which has already resulted in the successful resuscitation of a football player who had a sudden cardiac arrest on the field-of-play. Recently FIFA, in association with the Institute of Sports and Preventive Medicine in Saarbrücken, Germany, established a worldwide Sudden Death Registry with a view to documenting fatal events on the football field-of-play. These activities by F-MARC are testimony to FIFA's continued commitment to minimising sudden cardiac arrest while playing football. PMID:25878076

  4. Sudden cardiac death associated with methylone use.

    PubMed

    Carbone, Peter N; Carbone, David L; Carstairs, Shaun D; Luzi, Scott A

    2013-03-01

    The rise in popularity of "bath salts" as safe alternatives to MDMA (3,4-methylenedioxymethamphetamine), methamphetamine, and other illicit substances has resulted in increased scrutiny of the contents and toxicology associated with these products. We report a case of sudden death related to the synthetic cathinone methylone (3,4-methylenedioxy-N-methylcathinonmethylone) in a previously healthy 19-year-old man. Although several fatal case reports have been published involving methylone and other synthetic cathinones, this is the first reported case of sudden cardiac death associated with methylone use. Although lack of published data prevented a comparison of blood methylone concentrations between our case and existing reports, the amount of methylone we detected postmortem (0.07 mg/dL) is below those reported in MDMA-related fatalities. Our report suggests that methylone toxicity has been greatly underestimated by users of this synthetic cathinone. PMID:23403480

  5. Sudden Sensorineural Hearing Loss; Prognostic Factors

    PubMed Central

    Arjun, Dass; Neha, Goel; Surinder K, Singhal; Ravi, Kapoor

    2015-01-01

    Introduction: Sudden sensorineural hearing loss (SSNHL) is a frightening and frustrating symptom for the patient as well as the physician. Prognosis is affected by multiple factors including duration of hearing loss, presence of associated vertigo and tinnitus, and co-morbidities such as hypertension and diabetes. Materials and Methods: Forty subjects presenting to our department with features of sudden hearing loss were included in the study. Detailed otological history and examination, serial audiometric findings and course of disease were studied. Results: Subjects presenting late (in older age), having associated vertigo, hypertension and diabetes had a significantly lower rate of recovery. Conclusion: Only 60–65% of patients experiencing SSNHL recover within a period of 1 month; this rate is further affected by presence of multiple prognostic indicators. PMID:26568939

  6. Endotoxemia in sudden infant death syndrome.

    PubMed

    Platt, M S; Elin, R J; Hosseini, J M; Smialek, J E

    1994-09-01

    Endotoxemia has been proposed as a significant cause of Sudden Infant Death Syndrome (SIDS). We examined postmortem sera from left and right heart samples of 21 SIDS cases (1989 definition) and 23 controls. The controls were < 1 year of age and had died suddenly and unexpectedly of infection, abuse, suffocation, blunt injury, or fire and smoke inhalation. Endotoxin was measured without knowledge of the clinical status by using a kinetic modification of the chromogenic limulus amoebocyte lysate assay. The SIDS cases had insignificant concentrations of endotoxin in serum, whereas some of the controls who experienced blunt injury, abuse, or severe infection exhibited moderately elevated concentrations. Postmortem interval and postmortem blood culture results did not materially affect endotoxin concentrations. Thus, we conclude that endotoxemia is not a substantial pathophysiologic event in SIDS. PMID:7825560

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

    NASA Astrophysics Data System (ADS)

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

    1999-05-01

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

  8. Breakout coronal mass ejections from solar active regions

    NASA Astrophysics Data System (ADS)

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

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

  9. Simulation of Theoretical Most-Extreme Geomagnetic Sudden Commencements

    NASA Astrophysics Data System (ADS)

    Welling, Daniel; Love, Jeffrey; Wiltberger, Michael; Rigler, Erin; Gombosi, Tamas

    2016-04-01

    We report results from a numerical simulation of geomagnetic sudden commencements driven by solar wind conditions given by theoretical-limit extreme coronal-mass ejections (CMEs) estimated by Tsurutani and Lakhina [2014]. The CME characteristics at Earth are a step function that jumps from typical quiet values to 2700 km/s flow speed and a magnetic field magnitude of 127 nT. These values are used to drive three coupled models: a global magnetohydrodynamic (MHD) magnetospheric model (BATS-R-US), a ring current model (the Rice Convection Model, RCM), and a height-integrated ionospheric electrodynamics model (the Ridley Ionosphere Model, RIM), all coupled together using the Space Weather Modeling Framework (SWMF). Additionally, simulations from the Lyon-Fedder-Mobarry MHD model are performed for comparison. The commencement is simulated with both purely northward and southward IMF orientations. Low-latitude ground-level geomagnetic variations, both B and dB/dt, are estimated in response to the storm sudden commencement. For a northward interplanetary magnetic field (IMF) storm, the combined models predict a maximum sudden commencement response, Dst-equivalent of +200 nT and a maximum local dB/dt of ~200nT/s. While this positive Dst response is driven mainly by magnetopause currents, complicated and dynamic Birkeland current patterns also develop, which drive the strong dB/dt responses at high latitude. For southward IMF conditions, erosion of dayside magnetic flux allows magnetopause currents to approach much closer to the Earth, leading to a stronger terrestrial response (Dst-equivalent of +250 nT). Further, high latitude signals from Region 1 Birkeland currents move to lower latitudes during the southward IMF case, increasing the risk to populated areas around the globe. Results inform fundamental understanding of solar-terrestrial interaction and benchmark estimates for induction hazards of interest to the electric-power grid industry.

  10. [Relevancy of sudden death of cardiac origin].

    PubMed

    Báyes de Luna, Antoni; Kotzeva, Anna; Goldwasser, Diego; Subirana, Maite; Puig, Maria Teresa; Bayés-Genis, Toni; Cinca, Juan; Vázquez, Rafael

    2007-01-01

    Sudden death (SD) is of cardiac origin in approximately 80-90% of the cases and represents one of the most important challenges of the modern cardiology. Evaluation and understanding of its epidemiological, clinical and histopathological characteristics can lead to better results in its management. In Spain was carried a multicenter study MUSA with two arms: 1/ EULALIA: histopathological aspects of SD and 2/ MUSIC: SD in heart failure with focus on identification of population groups at risk, pathophysiological mechanisms of development and clinical prognostic markers. The preliminary conclusions of both studies are the following: 1/ EULALIA trial: From the total 121 sudden deaths, 109 (90%) were of cardiac origin and of these 45% presented characteristics of myocardial hypertrophy. The histopathological findings reveled that in only 48% of cases acute ischemic heart disease was present. In the other cases of ischemic heart disease the sudden death was probably by arrhythmic origin related with the presence of old myocardial infarction. This is the most striking difference compared with Anglo-Saxon studies. In the 29 cases of ACS, 18 had eroded and combination of eroded and ruptured plaques. In the cases of non-ACS plaques were stable in 20, and combination of stable and vulnerable plaques in 7 cases. Statistically significant results as independent predictors of sudden death gave the following markers: history of MI, cephalization of vessels in thorax X-ray, left atrium size > 45 mm, high levels of NT-proBNP and PIP, LBBB on ECG recording and body mass index. PMID:18938710

  11. Primordial spectra from sudden turning trajectory

    SciTech Connect

    Noumi, Toshifumi; Yamaguchi, Masahide E-mail: gucci@phys.titech.ac.jp

    2013-12-01

    Effects of heavy fields on primordial spectra of curvature perturbations are discussed in inflationary models with a sudden turning trajectory. When heavy fields are excited after the sudden turn and oscillate around the bottom of the potential, the following two effects are generically induced: deformation of the inflationary background spacetime and conversion interactions between adiabatic and isocurvature perturbations, both of which can affect the primordial density perturbations. In this paper, we calculate primordial spectra in inflationary models with sudden turning potentials taking into account both of the two effects appropriately. We find that there are some non-trivial correlations between the two effects in the power spectrum and, as a consequence, the primordial scalar power spectrum has a peak around the scale exiting the horizon at the turn. Though both effects can induce parametric resonance amplifications, they are shown to be canceled out for the case with the canonical kinetic terms. The peak feature and the scale dependence of bispectra are also discussed.

  12. FIP Bias Evolution in a Decaying Active Region

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    EPA Science Inventory

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    SciTech Connect

    Cargill, P. J.

    2014-03-20

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

  17. Static and Impulsive Models of Solar Active Regions

    NASA Technical Reports Server (NTRS)

    Patsourakos, S.; Klimchuk, James A.

    2008-01-01

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

  18. Plasma Composition in a Sigmoidal Anemone Active Region

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  19. Plasma composition in a sigmoidal anemone active region

    SciTech Connect

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

    2013-11-20

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

  20. SIMULATION OF THE FORMATION OF A SOLAR ACTIVE REGION

    SciTech Connect

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

    2010-09-01

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

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

    NASA Astrophysics Data System (ADS)

    Chatterjee, P.

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

  2. Static and Impulsive Models of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Patsourakos, S.; Klimchuk, J. A.

    2008-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Trikhunkov, Yaroslav; Zelenin, Egor

    2014-05-01

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

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

    PubMed Central

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

    1997-01-01

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

  5. Low-dimensional azimuthal characteristics of suddenly expanding axisymmetric flows

    NASA Astrophysics Data System (ADS)

    Tinney, C. E.; Glauser, M. N.; Eaton, E. L.; Taylor, J. A.

    2006-11-01

    Two rakes of cross-wire probes were used to capture the two-point velocity statistics in a flow through an axisymmetric sudden expansion. The expansion ratio of the facility is 3, and has a constant geometry. Measurements were acquired at a Reynolds number equal to 54 000, based on centreline velocity and inlet pipe diameter. The two-point velocity correlations were obtained along a plane normal to the flow (r,theta), at eleven downstream step-height positions spanning from the recirculating region, through reattachment, and into the redeveloping region of the flow. Measurements were acquired by means of a flying-hot-wire technique to overcome rectification errors near the outer wall of the pipe where flow recirculations were greatest. A mixed application of proper orthogonal (in radius) and Fourier decomposition (in azimuth) was performed at each streamwise location to provide insight into the dynamics of the most energetic modes in all regions of the flow. This multi-point analysis reveals that the flow evolves from the Fourier-azimuthal mode m {=} 2 (containing the largest amount of turbulent kinetic energy) in the recirculating region, to m {=} 1 in the reattachment and redeveloping regions of the flow. An eigenvector reconstruction of the kernel, using the most energetic modes from the decomposition, displays the spatial dependence of the Fourier-azimuthal modes and the characteristics that govern the turbulent shear layer and recirculating regions of the flow.

  6. A Case of Sudden Deafness with Intralabyrinthine Hemorrhage Intralabyrinthine Hemorrhage and Sudden Deafness

    PubMed Central

    Park, Jeong Jin; Jeong, Se Won; Lee, Jae Wook

    2015-01-01

    Sudden hearing deterioration may occur in our population, but it is difficult to explain the exact pathophysiology and the cause. Magnetic resonance imaging (MRI) in sudden sensorineural hearing loss (SSNHL) is usually useful to evaluate neural lesions such as acoustic schwannoma and hemorrhage in labyrinth. Recently some cases of SSNHL caused by intralabyrintine hemorrhage were reported by the advance of MRI. In the case of intralabyrintine hemorrhage, MRI showed a hyperintense signal in the labyrinth on the pre-contrast and contrast enhanced T1-weighted image and relatively weak intensity on T2-weighted image. The prognosis SSNHL by intralabyrintine hemorrhage is generally known to be poor. We report a case of sudden deafness with intralabyrintine hemorrhage who has a history of anticoagulant administration, with a review of literature. PMID:26771018

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

    NASA Astrophysics Data System (ADS)

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

    2002-06-01

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

  8. ASYMMETRY OF HELICITY INJECTION FLUX IN EMERGING ACTIVE REGIONS

    SciTech Connect

    Tian Lirong; Alexander, David

    2009-04-20

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

  9. Identifying the Main Driver of Active Region Outflows

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

  10. ABRUPT LONGITUDINAL MAGNETIC FIELD CHANGES IN FLARING ACTIVE REGIONS

    SciTech Connect

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

    2010-12-01

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

  11. Spectroscopic Observations of Fe XVIII in Solar Active Regions

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

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

    SciTech Connect

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

    2014-04-01

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

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

    SciTech Connect

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

    2012-12-10

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

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

    NASA Technical Reports Server (NTRS)

    Moore, Ronald L.; Falconer, David A.

    2009-01-01

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

  15. Estimating the potential for twenty-first century sudden climate change.

    PubMed

    Shindell, Drew

    2007-11-15

    I investigate the potential for sudden climate change during the current century. This investigation takes into account evidence from the Earth's history, from climate models and our understanding of the physical processes governing climate shifts. Sudden alterations to climate forcing seem to be improbable, with sudden changes instead most likely to arise from climate feedbacks. Based on projections from models validated against historical events, dramatic changes in ocean circulation appear unlikely. Ecosystem-climate feedbacks clearly have the potential to induce sudden change, but are relatively poorly understood at present. More probable sudden changes are large increases in the frequency of summer heatwaves and changes resulting from feedbacks involving hydrology. These include ice sheet decay, which may be set in motion this century. The most devastating consequences are likely to occur further in the future, however. Reductions in subtropical precipitation are likely to be the most severe hydrologic effects this century, with rapid changes due to the feedbacks of relatively well-understood large-scale circulation patterns. Water stress may become particularly acute in the Southwest US and Mexico, and in the Mediterranean and Middle East, where rainfall decreases of 10-25% (regionally) and up to 40% (locally) are projected. PMID:17666384

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

    PubMed Central

    Pagés, M; Alonso, C

    1978-01-01

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

  17. Sudden Sensorineural Hearing Loss: Primary Care Update.

    PubMed

    Leung, Marcia A; Flaherty, Anna; Zhang, Julia A; Hara, Jared; Barber, Wayne; Burgess, Lawrence

    2016-06-01

    The primary care physician's role in recognizing sudden sensorineural hearing (SSNHL) loss and delivering initial treatment is critical in the management of the syndrome. This role involves recognizing its clinical symptoms, distinguishing it from conductive hearing loss with the Weber tuning fork or the Rauch hum test, and urgent administration of high dose oral corticosteroids. Diagnosis and treatment should not be delayed for audiometric testing or referral to otolaryngology. This paper provides an update on the initial evaluation and treatment of this syndrome based on the literature and clinical guideline recommendations. PMID:27413627

  18. Sudden cardiac death: epidemiology and risk factors

    PubMed Central

    Adabag, A. Selcuk; Luepker, Russell V.; Roger, Véronique L.; Gersh, Bernard J.

    2016-01-01

    Sudden cardiac death (SCD) is an important public-health problem with multiple etiologies, risk factors, and changing temporal trends. Substantial progress has been made over the past few decades in identifying markers that confer increased SCD risk at the population level. However, the quest for predicting the high-risk individual who could be a candidate for an implantable cardioverter-defibrillator, or other therapy, continues. In this article, we review the incidence, temporal trends, and triggers of SCD, and its demographic, clinical, and genetic risk factors. We also discuss the available evidence supporting the use of public-access defibrillators. PMID:20142817

  19. A sudden change of a strange repeller

    NASA Astrophysics Data System (ADS)

    Ma, Ming-Quan; Wu, Shunguang; He, Da-Ren

    1998-03-01

    We have observed a transient chaos[1] after a boundary crisis in a simplified model of an impact oscillator. A strange repeller was found there and the scaling of the averaged life time was calculated both analytically and numerically. With the developing of the control parameter, the transient chaos was suddenly destroyed via a collision of a pair of the saddle nodes with a non-differential point of the mapping. The repeller disappeared and the scaling rules significantly changed as well after this collision. [1]:T.Tél, in ``Directions in Chaos'', vol.3, ed. by Hao Bai-lin, World Scientific Pub., Singapore, 1990.

  20. Sudden Sensorineural Hearing Loss: Primary Care Update

    PubMed Central

    Leung, Marcia A; Flaherty, Anna; Zhang, Julia A; Hara, Jared; Barber, Wayne

    2016-01-01

    The primary care physician's role in recognizing sudden sensorineural hearing (SSNHL) loss and delivering initial treatment is critical in the management of the syndrome. This role involves recognizing its clinical symptoms, distinguishing it from conductive hearing loss with the Weber tuning fork or the Rauch hum test, and urgent administration of high dose oral corticosteroids. Diagnosis and treatment should not be delayed for audiometric testing or referral to otolaryngology. This paper provides an update on the initial evaluation and treatment of this syndrome based on the literature and clinical guideline recommendations. PMID:27413627

  1. Probing the central regions of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Lohfink, Anne Maria

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

  2. Sudden insight is associated with shutting out visual inputs.

    PubMed

    Salvi, Carola; Bricolo, Emanuela; Franconeri, Steven L; Kounios, John; Beeman, Mark

    2015-12-01

    Creative ideas seem often to appear when we close our eyes, stare at a blank wall, or gaze out of a window--all signs of shutting out distractions and turning attention inward. Prior research has demonstrated that attention-related brain areas are differently active when people solve problems with sudden insight (the Aha! phenomenon), relative to deliberate, analytic solving. We directly investigated the relationship between attention deployment and problem solving by recording eye movements and blinks, which are overt indicators of attention, as people solved short, visually presented problems. In the preparation period, before problems eventually solved by insight, participants blinked more frequently and longer, and made fewer fixations, than before problems eventually solved by analysis. Immediately prior to solutions, participants blinked longer and looked away from the problem more often when solving by insight than when solving analytically. These phenomena extend prior research with a direct demonstration of dynamic differences in attention as people solve problems with sudden insight versus analytically. PMID:26268431

  3. Pathogenesis of sudden death following water immersion (immersion syndrome)

    NASA Technical Reports Server (NTRS)

    Buhring, M.; Spies, H. F.

    1981-01-01

    Sympathetic activity under cold stress is investigated. Predominantly vagal cardio-depressive reflexes are discussed besides currently known mechanisms of sudden death after water immersion. Pronounced circulatory centralization in diving animals as well as following exposure in cold water indicates additional sympathetic activity. In cold water baths of 15 C, measurements indicate an increase in plasma catecholamine levels by more than 300 percent. This may lead to cardiac arrhythmias by the following mechanisms: cold water essentially induces sinus bradycardia; brady-and tachycardiarrhythmias may supervene as secondary complications; sinusbradycardia may be enhanced by sympathetic hypertonus. Furthermore, ectopic dysrhythmias are liable to be induced by the strictly sympathetic innervation of the ventricle. Myocardial ischemia following a rise in peripheral blood pressure constitutes another arrhythmogenic factor. Some of these reactions are enhanced by alcohol intoxication.

  4. Sudden deep gas eruption nearby Rome's airport of Fiumicino

    NASA Astrophysics Data System (ADS)

    Ciotoli, Giancarlo; Etiope, Giuseppe; Florindo, Fabio; Marra, Fabrizio; Ruggiero, Livio; Sauer, Peter E.

    2013-11-01

    24 August 2013 a sudden gas eruption from the ground occurred in the Tiber river delta, nearby Rome's international airport of Fiumicino. We assessed that this gas, analogous to other minor vents in the area, is dominantly composed of deep, partially mantle-derived CO2, as in the geothermal gas of the surrounding Roman Comagmatic Province. Increased amounts of thermogenic CH4 are likely sourced from Meso-Cenozoic petroleum systems, overlying the deep magmatic fluids. We hypothesize that the intersection of NE-SW and N-S fault systems, which at regional scale controls the location of the Roman volcanic edifices, favors gas uprising through the impermeable Pliocene and deltaic Holocene covers. Pressurized gas may temporarily be stored below these covers or within shallower sandy, permeable layers. The eruption, regardless the triggering cause—natural or man-made, reveals the potential hazard of gas-charged sediments in the delta, even at distances far from the volcanic edifices.

  5. Is Sudden Hearing Loss Associated with Atherosclerosis?

    PubMed Central

    Rajati, Mohsen; Azarpajooh, Mahmoud Reza; Mouhebati, Mohsen; Nasrollahi, Mostafa; Salehi, Maryam; Khadivi, Ehsan; Nourizadeh, Navid; Hashemi, Firoozeh; Bakhshaee, Mehdi

    2016-01-01

    Introduction: Sudden sensorineural hearing-loss (SSNHL) patients constitute approximately 2–3% of referrals to ear, nose and throat (ENT) clinics. Several predisposing factors have been proposed for this condition; one of which is vascular disorders and perfusion compromise. In this research the atherosclerotic changes and their known risk factors are studied in SSNHL patients. Materials and Methods: Thirty SSNHL patients and 30 controls were evaluated with regard to cardiovascular risks including history, heart examination, blood pressure, body mass index, waist circumference, electrocardiogram, blood sugar, triglycerides, cholesterol, high-sensitivity C-reactive protein (HSCRP); also, carotid artery color Doppler study was undertaken to measure intima media thickness(IMT). Results: IMT and HSCRP showed an increased risk in the case group compared with the controls (P= 0.005 & P=0.001). However, waist circumference, history of smoking, fasting blood sugar, lipid profile, and electrocardiogram revealed no significant difference between the two groups. Interestingly, blood pressure and body mass index were higher in the controls in this study. Conclusion: Sudden sensorineural hearing loss may be associated with subclinical atherosclerosis. PMID:27429947

  6. Sudden cardiac death athletes: a systematic review

    PubMed Central

    2010-01-01

    Previous events evidence that sudden cardiac death (SCD) in athletes is still a reality and it keeps challenging cardiologists. Considering the importance of SCD in athletes and the requisite for an update of this matter, we endeavored to describe SCD in athletes. The Medline (via PubMed) and SciELO databases were searched using the subject keywords "sudden death, athletes and mortality". The incidence of SCD is expected at one case for each 200,000 young athletes per year. Overall it is resulted of complex dealings of factors such as arrhythmogenic substrate, regulator and triggers factors. In great part of deaths caused by heart disease in athletes younger than 35 years old investigations evidence cardiac congenital abnormalities. Athletes above 35 years old possibly die due to impairments of coronary heart disease, frequently caused by atherosclerosis. Myocardial ischemia and myocardial infarction are responsible for the most cases of SCD above this age (80%). Pre-participatory athletes' evaluation helps to recognize situations that may put the athlete's life in risk including cardiovascular diseases. In summary, cardiologic examinations of athletes' pre-competition routine is an important way to minimize the risk of SCD. PMID:20682064

  7. Magnetospheric plasma motion during a sudden commencement.

    NASA Technical Reports Server (NTRS)

    Lin, C.-A.; Young, D. T.; Wolf, R. A.

    1973-01-01

    A sudden commencement occurred at 2348 UT on Feb. 15, 1967, when the ATS-1 satellite was about 2 hr past local noon at a geocentric distance of 6.6 earth radii. Plasma was observed by the Suprathermal Ion Detector first to flow in the antisolar direction, as expected, but then to flow westward, for about 2 min, at about 50 km/sec. Analysis of ground magnetograms suggests that the surprising westward flow, which must have involved an electric field of about 10 mV/m at 6.6 earth radii, resulted from the ionosphere's reaction to the sudden commencement. Beginning about 2 min before the start of the westward flow at ATS-1, ground magnetometers near the foot of the ATS-1 field line typically recorded magnetic-field deflections of about 70 gamma, to the northeast. Taking the ground observations, assuming a height-integrated Hall conductivity of 1 mho, and a standoff distance of 7.2 earth radii inferred from Explorer 33 solar-wind data, a magnetospheric electric field is derived which agrees in magnitude and direction with that required to produce the observed flow at ATS-1.

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

    SciTech Connect

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

    2012-05-01

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

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

    NASA Technical Reports Server (NTRS)

    Moore, Ronald; Falconer, David; Sterling, Alphonse

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

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

    PubMed Central

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

    1996-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  13. Sudden arrhythmic death syndrome: a national survey of sudden unexplained cardiac death

    PubMed Central

    Behr, E R; Casey, A; Sheppard, M; Wright, M; Bowker, T J; Davies, M J; McKenna, W J; Wood, D A

    2007-01-01

    Objective To describe the characteristics of sudden arrhythmic death syndrome (SADS) and compare its incidence with official national mortality statistics for unascertained deaths. Design and setting Sudden unexplained deaths were prospectively surveyed through 117 coroners' jurisdictions in England. Consecutive cases meeting the following criteria were included: white Caucasian, aged 4–64 years, no history of cardiac disease, last seen alive within 12 h of death, normal coroner's autopsy, cardiac pathologist's confirmation of a normal heart and negative toxicology. Main outcome measures The estimated mortality from SADS was calculated and the official mortality statistics for unascertained causes of deaths in 4–64‐year‐olds was identified for the same time period. Results 115 coroner's cases were reported and 56 (49%) SADS victims were identified: mean age 32 years, range 7–64 years and 35 (63%) male. 7 of 39 cases (18%) had a family history of other premature sudden deaths (<45). The estimated mortality from SADS was 0.16/100 000 per annum (95% CI 0.12 to 0.21), compared with an official mortality of 0.10/100 000 per annum for International Classification of Diseases 798.1 (sudden death, cause unknown—instantaneous death) or 1.34/100 000 per annum for unascertained causes of death. Conclusions Deaths from SADS occur predominantly in young males. When compared with official mortality, the incidence of SADS may be up to eight times higher than estimated: more than 500 potential SADS cases per annum in England. Families with SADS carry genetic cardiac disease, placing them at risk of further sudden deaths. SADS should therefore be a certifiable cause of death prompting specialised cardiological evaluation of families. PMID:17237131

  14. The multi-thermal emission in solar active regions

    NASA Astrophysics Data System (ADS)

    Del Zanna, G.

    2013-10-01

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

  15. The solar atmosphere and the structure of active regions

    NASA Technical Reports Server (NTRS)

    Sturrock, P. A.

    1974-01-01

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

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

    PubMed Central

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

    2012-01-01

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

  17. Sudden unexpected death in epilepsy genetics: Molecular diagnostics and prevention.

    PubMed

    Goldman, Alica M; Behr, Elijah R; Semsarian, Christopher; Bagnall, Richard D; Sisodiya, Sanjay; Cooper, Paul N

    2016-01-01

    Epidemiologic studies clearly document the public health burden of sudden unexpected death in epilepsy (SUDEP). Clinical and experimental studies have uncovered dynamic cardiorespiratory dysfunction, both interictally and at the time of sudden death due to epilepsy. Genetic analyses in humans and in model systems have facilitated our current molecular understanding of SUDEP. Many discoveries have been informed by progress in the field of sudden cardiac death and sudden infant death syndrome. It is becoming apparent that SUDEP genomic complexity parallels that of sudden cardiac death, and that there is a pauci1ty of analytically useful postmortem material. Because many challenges remain, future progress in SUDEP research, molecular diagnostics, and prevention rests in international, collaborative, and transdisciplinary dialogue in human and experimental translational research of sudden death. PMID:26749013

  18. Constraint-induced sound therapy for sudden sensorineural hearing loss--behavioral and neurophysiological outcomes.

    PubMed

    Okamoto, Hidehiko; Fukushima, Munehisa; Teismann, Henning; Lagemann, Lothar; Kitahara, Tadashi; Inohara, Hidenori; Kakigi, Ryusuke; Pantev, Christo

    2014-01-01

    Sudden sensorineural hearing loss is characterized by acute, idiopathic hearing deterioration. We report here the development and evaluation of "constraint-induced sound therapy", which is based on a well-established neuro-rehabilitation approach, and which is characterized by the plugging of the intact ear ("constraint") and the simultaneous, extensive stimulation of the affected ear with music. The sudden sensorineural hearing loss patients who received the constraint-induced sound therapy in addition to the standard corticosteroid therapy showed significantly better recovery of hearing function compared to those who had only received corticosteroid treatments. Additionally, the brain activity obtained in a subgroup of patients suggested that the constraint-induced sound therapy could have prevented maladaptive auditory cortex reorganization. Constraint-induced sound therapy thus appears to be an effective, practical, and safe treatment option for sudden sensorineural hearing loss. PMID:24473277

  19. Constraint-induced sound therapy for sudden sensorineural hearing loss – behavioral and neurophysiological outcomes

    PubMed Central

    Okamoto, Hidehiko; Fukushima, Munehisa; Teismann, Henning; Lagemann, Lothar; Kitahara, Tadashi; Inohara, Hidenori; Kakigi, Ryusuke; Pantev, Christo

    2014-01-01

    Sudden sensorineural hearing loss is characterized by acute, idiopathic hearing deterioration. We report here the development and evaluation of “constraint-induced sound therapy”, which is based on a well-established neuro-rehabilitation approach, and which is characterized by the plugging of the intact ear (“constraint”) and the simultaneous, extensive stimulation of the affected ear with music. The sudden sensorineural hearing loss patients who received the constraint-induced sound therapy in addition to the standard corticosteroid therapy showed significantly better recovery of hearing function compared to those who had only received corticosteroid treatments. Additionally, the brain activity obtained in a subgroup of patients suggested that the constraint-induced sound therapy could have prevented maladaptive auditory cortex reorganization. Constraint-induced sound therapy thus appears to be an effective, practical, and safe treatment option for sudden sensorineural hearing loss. PMID:24473277

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

    SciTech Connect

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

    2013-10-01

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

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

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Dhakal, Suman; Chintzoglou, Georgios

    2015-04-01

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

  2. Estimated incidence and risk factors of sudden unexpected death

    PubMed Central

    Lin, Feng-Chang; Mehta, Neil; Mounsey, Louisa; Nwosu, Anthony; Pursell, Irion; Chung, Eugene H; Mounsey, J Paul; Simpson, Ross J

    2016-01-01

    Objective In this manuscript, we estimate the incidence and identify risk factors for sudden unexpected death in a socioeconomically and racially diverse population in one county in North Carolina. Estimates of the incidence and risk factors contributing to sudden death vary widely. The Sudden Unexpected Death in North Carolina (SUDDEN) project is a population-based investigation of the incidence and potential causes of sudden death. Methods From 3 March 2013 to 2 March 2014, all out-of-hospital deaths in Wake County, North Carolina, were screened to identify presumed sudden unexpected death among free-living residents between the ages of 18 and 64 years. Death certificate, public and medical records were reviewed and adjudicated to confirm sudden unexpected death cases. Results Following adjudication, 190 sudden unexpected deaths including 122 men and 68 women were identified. Estimated incidence was 32.1 per 100 000 person-years overall: 42.7 among men and 22.4 among women. The majority of victims were white, unmarried men over age 55 years, with unwitnessed deaths at home. Hypertension and dyslipidaemia were common in men and women. African-American women dying from sudden unexpected death were over-represented. Women who were under age 55 years with coronary disease accounted for over half of female participants with coronary artery disease. Conclusions The overall estimated incidence of sudden unexpected death may account for approximately 10% of all deaths classified as ‘natural’. Women have a lower estimated incidence of sudden unexpected death than men. However, we found no major differences in age or comorbidities between men and women. African-Americans and young women with coronary disease are at risk for sudden unexpected death. PMID:27042316

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

    SciTech Connect

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

    2009-08-01

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

  4. Sports and Marfan Syndrome: Awareness and Early Diagnosis Can Prevent Sudden Death.

    ERIC Educational Resources Information Center

    Salim, Mubadda A.; Alpert, Bruce S.

    2001-01-01

    Physicians who work with athletes play an important role in preventing sudden death related to physical activity in people who have Marfan syndrome. Flagging those who have the physical stigmata and listening for certain cardiac auscultation sounds are early diagnostic keys that can help prevent deaths. People with Marfan syndrome should be…

  5. Lightning activity and aerosols in the Mediterranean region

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  6. Risk stratification for sudden cardiac death

    PubMed Central

    Cutler, Michael J; Rosenbaum, David S.

    2009-01-01

    The proportion of cardiovascular deaths attributable to sudden cardiac death (SCD) is on the rise. Herein lies the rationale for developing risk stratification strategies to predict who will benefit from prophylactic ICD implantation. Current guidelines recommend prophylactic ICD therapy in patients with reduced left ventricular ejection fraction (LVEF). However, there are clear limitations in using LVEF alone to decide who should receive an ICD. There is mounting evidence that microvolt-level T wave alternans (TWA) is an important marker of arrhythmic risk. TWA is appealing because it non-invasively probes underlying electrophysiological substrate and has been linked to cellular mechanisms for arrhythmias. This review considers the clinical role of TWA for risk stratification of SCD. PMID:19631909

  7. Escherichia coli and Sudden Infant Death Syndrome

    PubMed Central

    Bettelheim, Karl A.; Goldwater, Paul N.

    2015-01-01

    This review examines the association of strains of Escherichia coli with sudden infant death syndrome (SIDS) and the possible role these bacteria play in this enigmatic condition. The review addresses evidence for E. coli in SIDS infants, potential sources of E. coli in the environment, colonization by commensal and pathogenic strains, the variety of currently accepted pathotypes, and how these pathotypes could compromise intestinal integrity and induce inflammation. Both intestinal and extraintestinal pathotypes are compared in relation to the apparent liability in which virulence traits can be gained or lost by strains of E. coli. The way in which E. coli infections fit with current views on infant sleeping position and other SIDS risk factors is highlighted. PMID:26191064

  8. Pathophysiology and prevention of sudden cardiac death.

    PubMed

    Goyal, Vineet; Jassal, Davinder S; Dhalla, Naranjan S

    2016-03-01

    Sudden cardiac death (SCD) is known to occur in individuals with diverse diseases. Each disease state has a specific etiology and pathophysiology, and is diagnosed and treated differently. Etiologies for SCD include cardiac arrhythmias, coronary artery disease, congenital coronary artery anomalies, hypertrophic cardiomyopathy, arrhythmogenic right ventricular dysplasia, dilated cardiomyopathy, and aortic valve stenosis. A potential unifying mechanism of SCD in these diseases involves a massive stimulation of the sympathetic nervous system's stress response and the subsequent elevation of circulating catecholamines. The diagnosis of cardiac diseases that contribute to an increased risk for SCD is accomplished by a combination of different techniques including electrocardiography, echocardiography, magnetic resonance imaging, and invasive cardiac catheterization. Several therapies including anti-arrhythmic drugs, β-blockers, and antiplatelet agents may be used as medical treatment in patients for the prevention of SCD. Invasive therapies including percutaneous angioplasty, coronary artery bypass surgery, and implantable cardioverter-defibrillators are also used in the clinical management of SCD. PMID:26651385

  9. Sudden hearing loss after dental treatment.

    PubMed

    Kansu, Leyla; Yilmaz, Ismail

    2013-08-01

    A 66-year-old man presented with impaired balance, tinnitus, sensation of blockage, and hearing loss in his left ear, which developed after dental treatment for dental pain 4 days previously. Treatment of the carious left upper second molar tooth had included pulp extirpation, canal expansion, and tooth filling under local anesthesia with articaine and epinephrine. Impaired balance decreased spontaneously within 3 days of dental treatment, but tinnitus and hearing loss persisted. Pure tone audiogram showed profound sensorineural hearing loss in the left ear, with a downslope from 40 to 100 dB, and an abnormal speech discrimination score (50%). Treatment included intravenous prednisolone, intratympanic dexamethasone, and oral betahistine and trimetazidine. The patient had improved hearing and resolution of tinnitus. Sudden hearing loss is rare after dental treatment, and awareness of this complication may prompt early referral for treatment and may improve recovery and prognosis. PMID:23642550

  10. Sudden infant death triggered by dive reflex.

    PubMed

    Matturri, L; Ottaviani, G; Lavezzi, A M

    2005-01-01

    The dive reflex is the reflex mechanism most frequently considered in the aetiopathogenesis of sudden infant death syndrome (SIDS). This seems to persist in human beings as an inheritance from diver birds and amphibians. It has been reported that washing the face with cold water or plunging into cold water can provoke cardiac deceleration through the intervention of the ambiguus and the vagal dorsal nuclei. This report describes a case of SIDS that offers a unique insight into the role of the dive reflex in determining a lethal outcome. Examination of the brainstem on serial sections revealed severe bilateral hypoplasia of the arcuate nucleus and gliosis of the other cardiorespiratory medullary nuclei. The coronary and cardiac conduction arteries presented early atherosclerotic lesions. The possible role of parental cigarette smoking in the pathogenesis of arcuate nucleus hypoplasia and early coronary atherosclerotic lesions is also discussed. PMID:15623488

  11. Ibogaine related sudden death: a case report.

    PubMed

    Papadodima, Stavroula A; Dona, Artemis; Evaggelakos, Christos I; Goutas, Nikolaos; Athanaselis, Sotirios A

    2013-10-01

    Ibogaine is a naturally occurring alkaloid derived from the roots of the rain forest shrub Tabernanthe iboga. Deaths have occurred temporarily related to the use of ibogaine. However, although not licensed as therapeutic drug, and despite evidence that ibogaine may disturb the rhythm of the heart, this alkaloid is currently used as an anti-addiction drug in alternative medicine for detoxification purposes. We report the case of a man who died suddenly 12-24 h after ibogaine use for alcohol detoxification treatment. In the autopsy liver cirrhosis and heavy fatty infiltration was found. The concentration of ibogaine was 2 mg/l. The potential risks of ibogaine use, especially for persons with pathological medical background, are discussed. PMID:24112325

  12. Stratospheric predictability and sudden stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Stan, Cristiana; Straus, David M.

    2009-06-01

    A comparative study of the limit of predictability in the stratosphere and troposphere in a coupled general circulation model is carried out using the National Center for Environmental Prediction (NCEP) Climate Forecast System Interactive Ensemble (CFSIE). In "identical twin experiments", we compare the forecast errors of zonal wind and potential temperature in the troposphere and stratosphere for various wave groups. The results show smaller intrinsic error growth in the lower stratosphere compared with troposphere. The limit of predictability of sudden stratospheric warming events, measured by the errors in the divergence of the Eliassen-Palm flux, is dominated by the amplification of small errors in the individual fields due to differences between the phase of the waves.

  13. [Periodic Repolarization Dynamics--innovative strategies for preventing sudden death].

    PubMed

    Rizas, Konstantinos; Bauer, Axel

    2016-04-01

    Sudden cardiac death (SCD) is the most common single cause of death in the industrialized world. Survivors of acute myocardial infarction (MI) are at increased risk of death. The vast majority of deaths occur in post-MI patients with preserved left ventricular ejection fraction (LVEF) for whom no prophylactic strategies exist. Periodic repolarization dynamics (PRD) is a novel electrocardiographic phenomenon that refers to low frequency (< 0.1 Hz) modulations of cardiac repolarization, most likely linked to sympathetic activity. Increased PRD is a strong and independent predictor of mortality after acute MI. PRD assessment allows to identify a new high risk group of post-MI patients with preserved LVEF (35-50 %) who have the same mortality risk as patients with LVEF ≤ 35 %. Future studies are needed to test the efficacy of preventive strategies in this new high risk group. PMID:27031208

  14. A possible explanation of sudden infant death syndrome (SIDS).

    PubMed

    Christos, G A; Christos, J A

    1993-09-01

    Research into (lucid) dreaming has shown that the images of a dream are supported by the corresponding body actions, utilizing those muscles which remain active during dreaming. We suggest that Sudden Infant Death Syndrome (SIDS) or Cot Death may be a result of an infant dreaming about its life as a fetus. In the course of that dream, since a fetus does not breathe in the usual sense, the infant may cease to breathe and die. Our hypothesis is consistent with the known facts about SIDS, including social factors such as sleeping position and climatic variation. We suggest that the risk of SIDS can be reduced by making the environment of the infant, as much as possible, unlike that of the womb. PMID:8259083

  15. [Sudden cardiac death during a city marathon run].

    PubMed

    Beutler, J; Schmid, E; Fischer, S; Hürlimann, S; Konrad, C

    2015-06-01

    Sudden cardiac death (SCD) in young athletes during physical stress is a rare event with an incidence of 1-3 deaths per 100,000 athletes per year. A coronary anomaly is the second most common cause of death following hypertrophic cardiomyopathy. Symptomatic prodromes occur in 20% of cases prior to the SCD event. This case report describes a 35-year-old male who collapsed near the finishing line of a half marathon run. Despite immediate resuscitation attempts and initial return of spontaneous circulation (ROSC), a pulseless electrical activity (PEA) followed and the patient died 1 h after arrival in the resuscitation unit. The autopsy revealed an anomalous left coronary artery (ALCA), which can lead to ischemia of the respective heart muscles under severe stress. PMID:26031561

  16. Seismic activity monitoring in the Izvorul Muntelui dam region

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

    The guidance system in a spacecraft determines spacecraft attitude by matching an observed star field to a star catalog....An APS(active pixel sensor)-based system can reduce mass and power consumption and radiation effects compared to a CCD(charge-coupled device)-based system...This paper reports an APS (active pixel sensor) with locally variable times, achieved through individual pixel reset (IPR).

  18. Automatic Tracking of Active Regions and Detection of Solar Flares in Solar EUV Images

    NASA Astrophysics Data System (ADS)

    Caballero, C.; Aranda, M. C.

    2014-05-01

    Solar catalogs are frequently handmade by experts using a manual approach or semi-automated approach. The appearance of new tools is very useful because the work is automated. Nowadays it is impossible to produce solar catalogs using these methods, because of the emergence of new spacecraft that provide a huge amount of information. In this article an automated system for detecting and tracking active regions and solar flares throughout their evolution using the Extreme UV Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) spacecraft is presented. The system is quite complex and consists of different phases: i) acquisition and preprocessing; ii) segmentation of regions of interest; iii) clustering of these regions to form candidate active regions which can become active regions; iv) tracking of active regions; v) detection of solar flares. This article describes all phases, but focuses on the phases of tracking and detection of active regions and solar flares. The system relies on consecutive solar images using a rotation law to track the active regions. Also, graphs of the evolution of a region and solar evolution are presented to detect solar flares. The procedure developed has been tested on 3500 full-disk solar images (corresponding to 35 days) taken from the spacecraft. More than 75 % of the active regions are tracked and more than 85 % of the solar flares are detected.

  19. Relation between Thermal and Magnetic Properties of Active Regions as a Probe of Coronal Heating Mechanisms

    NASA Astrophysics Data System (ADS)

    Yashiro, Seiji; Shibata, Kazunari

    2001-03-01

    We study the relation between thermal and magnetic properties of active regions in the corona observed with the soft X-ray telescope aboard Yohkoh. We derive the mean temperature and pressure of 64 mature active regions using the filter ratio technique, and examine the relationship of region size with temperature and pressure. We find that the temperature T of active regions increases with increasing region size L as T~L0.28, while the pressure P slightly decreases with the region size as P~L-0.16. We confirm the scaling law T~(PL)1/3 for mature active regions found by R. Rosner, W. H. Tucker, & G. S. Vaiana. We examined the magnetic properties of active regions by analyzing 31 active regions observed with the Solar and Heliospheric Observatory/Michelson Doppler Imager and find the following empirical scaling law between thermal and magnetic properties,Uth~Φ1.33,P~B0.78,where Uth, Φ, and B are the total thermal energy content, total magnetic flux, and average magnetic flux density of active regions, respectively. The former is consistent with the results of L. Golub et al., but the latter is not. Implications of our findings for coronal heating mechanisms are discussed.

  20. Spreading depolarization in the brainstem mediates sudden cardiorespiratory arrest in mouse SUDEP models.

    PubMed

    Aiba, Isamu; Noebels, Jeffrey L

    2015-04-01

    Cardiorespiratory collapse after a seizure is the leading cause of sudden unexpected death in epilepsy (SUDEP) in young persons, but why only certain individuals are at risk is unknown. To identify a mechanism for this lethal cardiorespiratory failure, we examined whether genes linked to increased SUDEP risk lower the threshold for spreading depolarization (SD), a self-propagating depolarizing wave that silences neuronal networks. Mice carrying mutations in Kv1.1 potassium channels (-/-) and Scn1a sodium ion channels (+/R1407X) phenocopy many aspects of human SUDEP. In mutant, but not wild-type mice, seizures initiated by topical application of 4-aminopyridine to the cortex led to a slow, negative DC potential shift recorded in the dorsal medulla, a brainstem region that controls cardiorespiratory pacemaking. This irreversible event slowly depolarized cells and inactivated synaptic activity, producing cardiorespiratory arrest. Local initiation of SD in this region by potassium chloride microinjection also elicited electroencephalographic suppression, apnea, bradycardia, and asystole, similar to the events seen in monitored human SUDEP. In vitro study of brainstem slices confirmed that mutant mice had a lower threshold for SD elicited by metabolic substrate depletion and that immature mice were at greater risk than adults. Deletion of the gene encoding tau, which prolongs life in these mutants, also restored the normal SD threshold in Kv1.1-mutant mouse brainstem. Thus, brainstem SD may be a critical threshold event linking seizures and SUDEP. PMID:25855492

  1. Spreading depolarization in the brainstem mediates sudden cardiorespiratory arrest in mouse SUDEP models

    PubMed Central

    Aiba, Isamu; Noebels, Jeffrey L.

    2016-01-01

    Cardiorespiratory collapse after a seizure is the leading cause of sudden unexpected death in epilepsy (SUDEP) in young persons, but why only certain individuals are at risk is unknown. To identify a mechanism for this lethal cardiorespiratory failure, we examined whether genes linked to increased SUDEP risk lower the threshold for spreading depolarization (SD), a self-propagating depolarizing wave that silences neuronal networks. Mice carrying mutations in Kv1.1 potassium channels (−/−) and Scn1a sodium ion channels (+/R1407X) phenocopy many aspects of human SUDEP. In mutant, but not wild-type mice, seizures initiated by topical application of 4-aminopyridine to the cortex led to a slow, negative DC potential shift recorded in the dorsal medulla, a brainstem region that controls cardiorespiratory pacemaking. This irreversible event slowly depolarized cells and inactivated synaptic activity, producing cardiorespiratory arrest. Local initiation of SD in this region by potassium chloride microinjection also elicited electroencephalographic suppression, apnea, bradycardia, and asystole, similar to the events seen in monitored human SUDEP. In vitro study of brainstem slices confirmed that mutant mice had a lower threshold for SD elicited by metabolic substrate depletion and that immature mice were at greater risk than adults. Deletion of the gene encoding tau, which prolongs life in these mutants, also restored the normal SD threshold in Kv1.1-mutant mouse brainstem. Thus, brainstem SD may be a critical threshold event linking seizures and SUDEP. PMID:25855492

  2. Fields and Flares: Understanding the Complex Magnetic Topologies of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Murray, Sophie A.

    2013-01-01

    Sunspots are regions of decreased brightness on the visible surface of the Sun (photosphere) that are associated with strong magnetic fields. They have been found to be locations associated with solar flares, which occur when energy stored in sunspot magnetic fields is suddenly released. The processes involved in flaring and the link between sunspot magnetic fields and flares is still not fully understood, and this thesis aims to gain a better understanding of these topics. The magnetic field evolution of a number of sunspot regions is examined using high spatial resolution data from the Hinode spacecraft. The research presented in this thesis gives insight into both photospheric and coronal magnetic field evolution of flaring regions. Significant increases in vertical field strength, current density, and field inclination angle towards the vertical are observed in the photosphere just hours before a flare occurs, which is on much shorter timescales than previously studied. First observations of spatial changes in field inclination across a magnetic neutral line (generally believed to be a typical source region of flares) are also discovered. 3D magnetic field extrapolation methods are used to study the coronal magnetic field, using the photospheric magnetic field data as a boundary condition. Magnetic energy and free magnetic energy are observed to increase significantly a few hours before a flare, and decrease afterwards, which is a similar trend to the photospheric field parameter changes observed. Evidence of partial Taylor relaxation is also detected after a flare, as predicted by several previous studies. The results outlined in this thesis show that this particular field of research is vital in furthering our understanding of the magnetic nature of sunspots and its link to flare processes.

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

    SciTech Connect

    Kumar, Brajesh; Venkatakrishnan, P.; Mathur, Savita; Tiwari, Sanjiv Kumar; Garcia, R. A. E-mail: pvk@prl.res.in E-mail: tiwari@mps.mpg.de

    2011-12-10

    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 <{nu} < 8 mHz) and a feeble enhancement in the p-mode oscillations (2 <{nu} < 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

  4. Synthetic Physical Interactions Map Kinetochore-Checkpoint Activation Regions

    PubMed Central

    Ólafsson, Guðjón; Thorpe, Peter H.

    2016-01-01

    The spindle assembly checkpoint (SAC) is a key mechanism to regulate the timing of mitosis and ensure that chromosomes are correctly segregated to daughter cells. The recruitment of the Mad1 and Mad2 proteins to the kinetochore is normally necessary for SAC activation. This recruitment is coordinated by the SAC kinase Mps1, which phosphorylates residues at the kinetochore to facilitate binding of Bub1, Bub3, Mad1, and Mad2. There is evidence that the essential function of Mps1 is to direct recruitment of Mad1/2. To test this model, we have systematically recruited Mad1, Mad2, and Mps1 to most proteins in the yeast kinetochore, and find that, while Mps1 is sufficient for checkpoint activation, recruitment of either Mad1 or Mad2 is not. These data indicate an important role for Mps1 phosphorylation in SAC activation, beyond the direct recruitment of Mad1 and Mad2. PMID:27280788

  5. Synthetic Physical Interactions Map Kinetochore-Checkpoint Activation Regions.

    PubMed

    Ólafsson, Guðjón; Thorpe, Peter H

    2016-01-01

    The spindle assembly checkpoint (SAC) is a key mechanism to regulate the timing of mitosis and ensure that chromosomes are correctly segregated to daughter cells. The recruitment of the Mad1 and Mad2 proteins to the kinetochore is normally necessary for SAC activation. This recruitment is coordinated by the SAC kinase Mps1, which phosphorylates residues at the kinetochore to facilitate binding of Bub1, Bub3, Mad1, and Mad2. There is evidence that the essential function of Mps1 is to direct recruitment of Mad1/2. To test this model, we have systematically recruited Mad1, Mad2, and Mps1 to most proteins in the yeast kinetochore, and find that, while Mps1 is sufficient for checkpoint activation, recruitment of either Mad1 or Mad2 is not. These data indicate an important role for Mps1 phosphorylation in SAC activation, beyond the direct recruitment of Mad1 and Mad2. PMID:27280788

  6. Sudden birth versus sudden death of entanglement for the extended Werner-like state in a dissipative environment

    NASA Astrophysics Data System (ADS)

    Shan, Chuan-Jia; Chen, Tao; Liu, Ji-Bing; Cheng, Wei-Wen; Liu, Tang-Kun; Huang, Yan-Xia; Li, Hong

    2010-06-01

    In this paper, we investigate the dynamical behaviour of entanglement in terms of concurrence in a bipartite system subjected to an external magnetic field under the action of dissipative environments in the extended Werner-like initial state. The interesting phenomenon of entanglement sudden death as well as sudden birth appears during the evolution process. We analyse in detail the effect of the purity of the initial entangled state of two qubits via Heisenberg XY interaction on the apparition time of entanglement sudden death and entanglement sudden birth. Furthermore, the conditions on the conversion of entanglement sudden death and entanglement sudden birth can be generalized when the initial entangled state is not pure. In particular, a critical purity of the initial mixed entangled state exists, above which entanglement sudden birth vanishes while entanglement sudden death appears. It is also noticed that stable entanglement, which is independent of different initial states of the qubits (pure or mixed state), occurs even in the presence of decoherence. These results arising from the combination of the extended Werner-like initial state and dissipative environments suggest an approach to control and enhance the entanglement even after purity induced sudden birth, death and revival.

  7. Overexpression of KCNN3 results in sudden cardiac death

    PubMed Central

    Mahida, Saagar; Mills, Robert W.; Tucker, Nathan R.; Simonson, Bridget; Macri, Vincenzo; Lemoine, Marc D.; Das, Saumya; Milan, David J.; Ellinor, Patrick T.

    2014-01-01

    Background A recent genome-wide association study identified a susceptibility locus for atrial fibrillation at the KCNN3 gene. Since the KCNN3 gene encodes for a small conductance calcium-activated potassium channel, we hypothesized that overexpression of the SK3 channel increases susceptibility to cardiac arrhythmias. Methods and results We characterized the cardiac electrophysiological phenotype of a mouse line with overexpression of the SK3 channel. We generated homozygote (SK3T/T) and heterozygote (SK3+/T) mice with overexpression of the channel and compared them with wild-type (WT) controls. We observed a high incidence of sudden death among SK3T/T mice (7 of 19 SK3T/T mice). Ambulatory monitoring demonstrated that sudden death was due to heart block and bradyarrhythmias. SK3T/T mice displayed normal body weight, temperature, and cardiac function on echocardiography; however, histological analysis demonstrated that these mice have abnormal atrioventricular node morphology. Optical mapping demonstrated that SK3T/T mice have slower ventricular conduction compared with WT controls (SK3T/T vs. WT; 0.45 ± 0.04 vs. 0.60 ± 0.09 mm/ms, P = 0.001). Programmed stimulation in 1-month-old SK3T/T mice demonstrated inducible atrial arrhythmias (50% of SK3T/T vs. 0% of WT mice) and also a shorter atrioventricular nodal refractory period (SK3T/T vs. WT; 43 ± 6 vs. 52 ± 9 ms, P = 0.02). Three-month-old SK3T/T mice on the other hand displayed a trend towards a more prolonged atrioventricular nodal refractory period (SK3T/T vs. WT; 61 ± 1 vs. 52 ± 6 ms, P = 0.06). Conclusion Overexpression of the SK3 channel causes an increased risk of sudden death associated with bradyarrhythmias and heart block, possibly due to atrioventricular nodal dysfunction. PMID:24296650

  8. 50 CFR 216.240 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Active Sonar Training (AFAST) § 216.240 Specified activity and specified geographical region. (a... Navy is only authorized if it occurs incidental to the use of the following mid-frequency active sonar (MFAS) sources, high frequency active sonar (HFAS) sources, explosive sonobuoys, or similar sources,...

  9. 50 CFR 216.240 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Active Sonar Training (AFAST) § 216.240 Specified activity and specified geographical region. (a... Navy is only authorized if it occurs incidental to the use of the following mid-frequency active sonar (MFAS) sources, high frequency active sonar (HFAS) sources, explosive sonobuoys, or similar sources,...

  10. 50 CFR 216.240 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Active Sonar Training (AFAST) § 216.240 Specified activity and specified geographical region. (a... Navy is only authorized if it occurs incidental to the use of the following mid-frequency active sonar (MFAS) sources, high frequency active sonar (HFAS) sources, explosive sonobuoys, or similar sources,...

  11. The Atlantic Canada-New England Region and Environment. A Learning Activity Packet.

    ERIC Educational Resources Information Center

    Maine Univ., Orono. New England - Atlantic Provinces - Quebec Center.

    In this Learning Activity Packet (LAP) students examine the geographic and ecological bases of the Eastern international region. The overall objective of activities is to help students comprehend the man-earth relationship concept. By studying this familiar relevant region students gain geographic knowledge and skills applicable to other areas.…

  12. 76 FR 58533 - Powder River Regional Coal Team Activities; Notice of Public Meeting in Casper, WY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-21

    ... Bureau of Land Management Powder River Regional Coal Team Activities; Notice of Public Meeting in Casper, WY AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Public Meeting. SUMMARY: The Powder... management activities in the Powder River Coal Production Region. DATES: The RCT meeting will begin at 9...

  13. 78 FR 23951 - Powder River Regional Coal Team Activities: Notice of Public Meeting in Casper, Wyoming

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-23

    ... Bureau of Land Management Powder River Regional Coal Team Activities: Notice of Public Meeting in Casper, Wyoming AGENCY: Bureau of Land Management, Interior. ACTION: Notice of public meeting. SUMMARY: The Powder... management activities in the Powder River Coal Production Region. DATES: The RCT meeting will begin at 9...

  14. Diode laser threshold current density and lasing wavelength as functions of active region thickness

    SciTech Connect

    Streifer, W.; Scifres, D.R.; Burnham, R.D.

    1983-03-01

    Based on a simple model of the band-to-band absorption of a diode laser active region, we formulatean expression for modal gain as a function of pumping current. Using this result yields expressions for threshold current density and lasing photon energy which depend on device parameters including active region thickness, laser length, internal losses, facet reflectivity, etc.

  15. Involvement of neuroleptic drugs in selenium deficiency and sudden death of cardiac origin: study and human post-mortem examination.

    PubMed

    Hamdan, Lamia; Bost, Muriel; Chazot, Guy; Bui-Xuan, Bernard; Vaillant, Fanny; Dehina, Leila; Descotes, Jacques; Tabib, Alain; Mamou, Zahida; Timour, Quadiri

    2012-06-01

    The involvement of psychotropic drugs in sudden deaths has been highlighted. The objective of this work was to establish a link between selenium levels in heart tissue, psychotropic treatment and sudden death. Selenium levels were measured by electrothermal atomic absorption spectroscopy post-mortem in heart, brain and liver. Histological examination evidenced dilated cardiomyopathy in 45% of cases, left ventricular hypertrophy in 36%, and ischemic coronaropathy in 18%. A significant reduction of myocardial selenium levels compared to controls was seen in patients treated with neuroleptic drugs or meprobamate. No changes in brain or liver selenium levels were seen. These results suggest that selenium deficiency can facilitate sudden death in patients on psychotropic drugs. The reduced activity of glutathione peroxidase due to selenium deficiency can result in augmented oxidative stress in myocardial cells and myocardiopathy leading to sudden death. PMID:22664334

  16. Non-locality Sudden Death in Tripartite Systems

    SciTech Connect

    Jaeger, Gregg; Ann, Kevin

    2009-03-10

    Bell non-locality sudden death is the disappearance of non-local properties in finite times under local phase noise, which decoheres states only in the infinite-time limit. We consider the relationship between decoherence, disentanglement, and Bell non-locality sudden death in bipartite and tripartite systems in specific large classes of state preparation.

  17. New Areas for Preventive Programing: Sudden Infant Death Syndrome.

    ERIC Educational Resources Information Center

    Lowman, Joseph

    Crisis intervention programs for persons experiencing the sudden death of family members or surviving natural disasters have been advocated as methods of primary prevention, although few have actually been implemented. A program utilizing nurses to deliver grief intervention to parents losing a baby to Sudden Infant Death Syndrome (SIDS) was…

  18. Observations of Small-scale IRIS Bombs (Reconnection Events) in an Evolving Active Region

    NASA Astrophysics Data System (ADS)

    Madsen, C. A.; Tian, H.; DeLuca, E. E.

    2015-12-01

    We present the first Interface Region Imaging Spectrograph (IRIS) observations of small-scale bombs evolving with their host active region. Bombs appear most clearly in the IRIS 1330 Å and 1400 Å slit-jaw images as small (~1 arcsec), compact, intense brightenings at transition region temperatures. Their NUV/FUV emission spectra exhibit dramatic line splitting and strong absorption features indicative of bidirectional flows from magnetic reconnection embedded deep within the cool lower solar atmosphere. The bombs may contribute significantly to the heating of the solar atmosphere in active regions; however, it's unclear how prevalent the bombs are throughout the lifetime of an active region. Using a semi-automated detection method, we locate bombs within AR 11850 over the course of four observations from 06:00 UT on September 25, 2013 until 11:30 UT the next day. The active region is first observed in an emerging phase and rapidly grows into a mature active region with well-developed sunspots. The bomb occurrence rate drops dramatically as the active region fully emerges. We also find that the bombs fall into two distinct populations: one appears largely during active region emergence and contains a majority of the bombs, while the other population is present regardless of active region age. The first population of bombs is typically found embedded in the low-lying loops prominent in the young active region. Furthermore, we use Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) line-of-sight magnetograms to show that the bombs associated with the first population occur at the boundaries between the upward and downward flux of small, isolated bipolar regions. These regions dissipate as the active region emerges and reconfigures its magnetic field into two large network patches of upward and downward flux with a clear inversion line. The second, smaller population of bombs usually occurs far from the active region loop structures in the plage and

  19. Mechanically induced sudden death in chest wall impact (commotio cordis).

    PubMed

    Link, Mark S

    2003-01-01

    Sudden death due to nonpenetrating chest wall impact in the absence of injury to the ribs, sternum and heart is known as commotio cordis. Although once thought rare, an increasing number of these events have been reported. Indeed, a significant percentage of deaths on the athletic field are due to chest wall impact. Commotio cordis is most frequently observed in young individuals (age 4-18 years), but may also occur in adults. Sudden death is instantaneous or preceded by several seconds of lightheadedness after the chest wall blow. Victims are most often found in ventricular fibrillation, and successful resuscitation is more difficult than expected given the young age, excellent health of the victims, and the absence of structural heart disease. Autopsy examination is notable for the lack of any significant cardiac or thoracic abnormalities. In an experimental model of commotio cordis utilizing anesthetized juvenile swine, ventricular fibrillation can be produced by a 30 mph baseball strike if the strike occurred during the vulnerable period of repolarization, on the upslope of the T-wave. Energy of the impact object was also found to be a critical variable with 40 mph baseballs more likely to cause ventricular fibrillation than velocities less or greater than 40 mph. In addition, more rigid impact objects and blows directly over the center of the chest were more likely to cause ventricular fibrillation. Peak left ventricular pressure generated by the chest wall blow correlated with the risk of ventricular fibrillation. Activation of the K(+)(ATP) channel is a likely cause of the ventricular fibrillation produced by chest wall blows. Successful resuscitation is attainable with early defibrillation. PMID:12732277

  20. Automatic detection of sudden commencements using neural networks

    NASA Astrophysics Data System (ADS)

    Segarra, A.; Curto, J. J.

    2013-07-01

    The aim of this work is to develop an automatic system to detect sudden commencements (SCs). SCs are produced by a sudden increase of solar wind dynamic pressure and are detected simultaneously everywhere on the ground (Araki, 1994). Since 1975, Ebro Observatory is responsible to elaborate the list of SC, following the morphological rules given by Mayaud (1973). Nowadays, this task is still done manually and presents some difficulties; the most worrying one is the decreasing number of observatories who collaborate with this task because most of them opted for the installation of unattended observatories. Hence, the necessity of an alternative method to continue the service becomes a urgency. The automatic method presented in this work is based on neural network analysis. To succeed with neural networks, we did a previous work of characterization and parameterization of SCs by statistical analysis. In this way, we focused on the determination of the appropriate parameters to be used as the inputs of the network which resulted to be: slope, change of magnetic activity and difference of the levels before and after the jump. We worked with X component and also with Y component. An important criteria introduced in this work is the necessary coherence of the results obtained with this new automatic method with those obtained with the manual method and reported in the old list of SC. Finally, the neural network is able to recognize the SC pattern successfully, but now this is achieved in a non-manned way. A robust quasi-real-time detection can be undertaken in the future.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    MAG4 is a technique of forecasting an active region's rate of production of major flares in the coming few days from a free-magnetic-energy proxy. We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region's major-flare productivity from alternative observed aspects of the active region. We demonstrate the method by measuring the difference in performance between the "Present MAG4" technique and each of three alternative techniques, called "McIntosh Active-Region Class," "Total Magnetic Flux," and "Next MAG4." We do this by using (1) the MAG4 database of magnetograms and major-flare histories of sunspot active regions, (2) the NOAA table of the major-flare productivity of each of 60 McIntosh active-region classes of sunspot active regions, and (3) five technique-performance metrics (Heidke Skill Score, True Skill Score, Percent Correct, Probability of Detection, and False Alarm Rate) evaluated from 2000 random two-by-two contingency tables obtained from the databases. We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4).

  2. TEC disturbances during major Sudden Stratospheric Warmings in the mid-latitude ionosphere.

    NASA Astrophysics Data System (ADS)

    Polyakova, Anna; Voeykov, Sergey; Chernigovskaya, Marina; Perevalova, Natalia

    Using total electron content (TEC) global ionospheric maps, dual-frequency GPS receivers TEC data and MLS (Microwave Limb Sounder, EOS Aura) atmospheric temperature data the ionospheric disturbances during the strong sudden stratospheric warmings (SSWs) of 2008/2009 and 2012/2013 winters are investigated in Russia's Asia region. It is established that during the SSW maximum the midday TEC decrease and the night/morning TEC increase compared to quiet days are observed in the mid-latitude ionosphere. As a result it caused the decrease of the diurnal TEC variations amplitude of about two times in comparison with the undisturbed level. The analysis of TEC deviations from the background level during the SSWs has shown that deviations dynamics vary depending on the observation point position. Negative deviations of TEC are registered in the ionosphere above the region of maximum stratosphere heating (the region of the stratospheric circulation change) as well as above the anticyclone. On the contrary, TEC values increase compared to the quiet day's values above the stratosphere cyclone. It is shown that during maximum phase of a warming, and within several days after it the amplification of wave TEC variations intensity with periods of up to 60 min is registered in ionosphere. The indicated effects may be attributed to the vertical transfer of molecular gas from a stratospheric heating region to the thermosphere as well as to the increase in activity of planetary and gravity waves which is usually observed during strong SSWs. The study is supported by the RF President Grant of Public Support for RF Leading Scientific Schools (NSh-2942.2014.5), the RF President Grant No. MK-3771.2012.5 and RFBR Grant No. 12-05-00865_а.

  3. Sudden death of an infant with cardiac, nervous system and genetic involvement – a case report

    PubMed Central

    2013-01-01

    Abstract We present a case of sudden death of a 1-month-old male infant with heart, brainstem and genetic polymorphism involvement. Previously considered quite healthy, the child died suddenly and unexpectedly during sleep. The autopsy protocol included an in-depth anatomopathological examination of both the autonomic nervous system and the cardiac conduction system, and molecular analysis of the serotonin transporter gene promoter region, in which a specific genetic condition seems to be associated with sudden infant death. Histological examination revealed the presence of congenital cardiac alterations (hypertrophic cardiomyopathy and an accessory Mahaim fiber in the cardiac conduction system), severe hypodevelopment of all the raphe nuclei and a heterozygous genotype L/S related to the serotonin transporter gene. The sudden death of this infant was the unavoidable outcome of a complex series of congenital anomalies, each predisposing to SIDS. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/3480540091031788 PMID:24053176

  4. Atmospheric energetics in regions of intense convective activity

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.

    1977-01-01

    Synoptic-scale budgets of kinetic and total potential energy are computed using 3- and 6-h data at nine times from NASA's fourth Atmospheric Variability Experiment (AVE IV). Two intense squall lines occurred during the period. Energy budgets for areas that enclose regions of intense convection are shown to have systematic changes that relate to the life cycles of the convection. Some of the synoptic-scale energy processes associated with the convection are found to be larger than those observed in the vicinity of mature cyclones. Volumes enclosing intense convection are found to have large values of cross-contour conversion of potential to kinetic energy and large horizontal export of kinetic energy. Although small net vertical transport of kinetic energy is observed, values at individual layers indicate large upward transport. Transfer of kinetic energy from grid to subgrid scales of motion occurs in the volumes. Latent heat release is large in the middle and upper troposphere and is thought to be the cause of the observed cyclic changes in the budget terms. Total potential energy is found to be imported horizontally in the lower half of the atmosphere, transported aloft, and then exported horizontally. Although local changes of kinetic energy and total potential energy are small, interaction between volumes enclosing convection with surrounding larger volumes is quite large.

  5. Structural imaging biomarkers of sudden unexpected death in epilepsy

    PubMed Central

    Wandschneider, Britta; Koepp, Matthias; Scott, Catherine; Micallef, Caroline; Balestrini, Simona; Sisodiya, Sanjay M.; Thom, Maria; Harper, Ronald M.; Sander, Josemir W.; Vos, Sjoerd B.; Duncan, John S.; Lhatoo, Samden

    2015-01-01

    Sudden unexpected death in epilepsy is a major cause of premature death in people with epilepsy. We aimed to assess whether structural changes potentially attributable to sudden death pathogenesis were present on magnetic resonance imaging in people who subsequently died of sudden unexpected death in epilepsy. In a retrospective, voxel-based analysis of T1 volume scans, we compared grey matter volumes in 12 cases of sudden unexpected death in epilepsy (two definite, 10 probable; eight males), acquired 2 years [median, interquartile range (IQR) 2.8] before death [median (IQR) age at scanning 33.5 (22) years], with 34 people at high risk [age 30.5 (12); 19 males], 19 at low risk [age 30 (7.5); 12 males] of sudden death, and 15 healthy controls [age 37 (16); seven males]. At-risk subjects were defined based on risk factors of sudden unexpected death in epilepsy identified in a recent combined risk factor analysis. We identified increased grey matter volume in the right anterior hippocampus/amygdala and parahippocampus in sudden death cases and people at high risk, when compared to those at low risk and controls. Compared to controls, posterior thalamic grey matter volume, an area mediating oxygen regulation, was reduced in cases of sudden unexpected death in epilepsy and subjects at high risk. The extent of reduction correlated with disease duration in all subjects with epilepsy. Increased amygdalo-hippocampal grey matter volume with right-sided changes is consistent with histo-pathological findings reported in sudden infant death syndrome. We speculate that the right-sided predominance reflects asymmetric central influences on autonomic outflow, contributing to cardiac arrhythmia. Pulvinar damage may impair hypoxia regulation. The imaging findings in sudden unexpected death in epilepsy and people at high risk may be useful as a biomarker for risk-stratification in future studies. PMID:26264515

  6. Simulated sudden stratospheric warming - Synoptic evolution

    NASA Technical Reports Server (NTRS)

    Blackshear, W. T.; Grose, W. L.; Turner, R. E.

    1987-01-01

    An analysis is presented of a sudden stratospheric warming event which occurred spontaneously during a general circulation model simulation of the global atmospheric circulation. Two separate warming pulses exhibit the same dynamical evolution with a 'cycle' of about two weeks. Two distinct phases of the warming cycle are apparent: (1) the generation of an intense localized warm cell in conjunction with significant adiabatic heating associated with cross-isobar flow which has been induced by vertically propagating long wave disturbances; and (2) the northward transport of that warm cell via advection by the essentially geostrophic windfield corresponding to an intense, offset polar cyclone, in conjunction with a strong Aleutian anticyclone. During the first warming pulse in January, a moderate Aleutian anticyclone was in place prior to the warming cycle and was intensified by interaction with an eastward traveling anticyclone induced by the differential advection of the warm cell. The second warming pulse occurred in early February with a strong Aleutian anticyclone already established. In contrast to the January event, the warming in February culminated with reversal of the zonal westerlies to easterlies over a significant depth of the stratosphere.

  7. Cardiac Innervation and Sudden Cardiac Death

    PubMed Central

    Fukuda, Keiichi; Kanazawa, Hideaki; Aizawa, Yoshiyasu; Ardell, Jeffrey L.; Shivkumar, Kalyanam

    2015-01-01

    Afferent and efferent cardiac neurotransmission via the cardiac nerves intricately modulates nearly all physiological functions of the heart (chronotropy, dromotropy, lusitropy and inotropy). Afferent information from the heart is transmitted to higher levels of the nervous system for processing (intrinsic cardiac nervous system, extracardiac-intrathoracic ganglia, spinal cord, brain stem and higher centers) which ultimately results in efferent cardiomotor neural impulses (via the sympathetic and parasympathetic nerves). This system forms interacting feedback loops that provide physiological stability for maintaining normal rhythm and life-sustaining circulation. This system also ensures that there is fine-tuned regulation of sympathetic-parasympathetic balance in the heart under normal and stressed states in the short (beat to beat), intermediate (minutes-hours) and long term (days-years). This important neurovisceral /autonomic nervous system also plays a major role in the pathophysiology and progression of heart disease, including heart failure and arrhythmias leading to sudden cardiac death (SCD). Transdifferentiation of neurons in heart failure, functional denervation, cardiac and extra-cardiac neural remodeling have also been identified and characterized during the progression of disease. Recent advances in understanding the cellular and molecular processes governing innervation and the functional control of the myocardium in health and disease provides a rational mechanistic basis for development of neuraxial therapies for preventing SCD and other arrhythmias. Advances in cellular, molecular, and bioengineering realms have underscored the emergence of this area as an important avenue of scientific inquiry and therapeutic intervention. PMID:26044253

  8. Storm Sudden Commencements Without Interplanetary Shocks

    NASA Astrophysics Data System (ADS)

    Park, Wooyeon; Lee, Jeongwoo; Yi, Yu; Ssessanga, Nicholas; Oh, Suyeon

    2015-09-01

    Storm sudden commencements (SSCs) occur due to a rapid compression of the Earth's magnetic field. This is generally believed to be caused by interplanetary (IP) shocks, but with exceptions. In this paper we explore possible causes of SSCs other than IP shocks through a statistical study of geomagnetic storms using SYM-H data provided by the World Data Center for Geomagnetism ? Kyoto and by applying a superposed epoch analysis to simultaneous solar wind parameters obtained with the Advanced Composition Explorer (ACE) satellite. We select a total of 274 geomagnetic storms with minimum SYM-H of less than ?30nT during 1998-2008 and regard them as SSCs if SYM-H increases by more than 10 nT over 10 minutes. Under this criterion, we found 103 geomagnetic storms with both SSC and IP shocks and 28 storms with SSC not associated with IP shocks. Storms in the former group share the property that the strength of the interplanetary magnetic field (IMF), proton density and proton velocity increase together with SYM-H, implying the action of IP shocks. During the storms in the latter group, only the proton density rises with SYM-H. We find that the density increase is associated with either high speed streams (HSSs) or interplanetary coronal mass ejections (ICMEs), and suggest that HSSs and ICMEs may be alternative contributors to SSCs.

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

    NASA Technical Reports Server (NTRS)

    Neidig, Donald F.; Hagyard, Mona J.; Machado, Marcos E.; Smith, Jesse B., Jr.

    1986-01-01

    The magnetic and dynamical circumstances leading to the 1B/M4 flare of November 5, 1980 are studied, and a strong association is found between the buildup of magnetic shear and the onset of flare activity within the active region. The development of shear, as observed directly in vector magnetograms, is consistent in detail with the dynamical history of the active region and identifies the precise location of the optical and hard-X-ray kernels of the flare emission.

  10. Colors of active regions on comet 67P

    NASA Astrophysics Data System (ADS)

    Oklay, N.; Vincent, J.-B.; Sierks, H.; Besse, S.; Fornasier, S.; Barucci, M. A.; Lara, L.; Scholten, F.; Preusker, F.; Lazzarin, M.; Pajola, M.; La Forgia, F.

    2015-10-01

    The OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) scientific imager (Keller et al. 2007) is successfully delivering images of comet 67P/Churyumov-Gerasimenko from its both wide angle camera (WAC) and narrow angle camera (NAC) since ESA's spacecraft Rosetta's arrival to the comet. Both cameras are equipped with filters covering the wavelength range of about 200 nm to 1000 nm. The comet nucleus is mapped with different combination of the filters in resolutions up to 15 cm/px. Besides the determination of the surface morphology in great details (Thomas et al. 2015), such high resolution images provided us a mean to unambiguously link some activity in the coma to a series of pits on the nucleus surface (Vincent et al. 2015).

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

    NASA Astrophysics Data System (ADS)

    Bourdin, Philippe A.

    2015-08-01

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

  12. Enhanced internal gravity wave activity and breaking over the northeastern Pacific-eastern Asian region

    NASA Astrophysics Data System (ADS)

    Šácha, P.; Kuchař, A.; Jacobi, C.; Pišoft, P.

    2015-11-01

    We have found a stratospheric area of anomalously low annual cycle amplitude and specific dynamics in the stratosphere over the northeastern Pacific-eastern Asia coastal region. Using GPS radio occultation density profiles from the Formosat Satellite Mission 3/Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT-3/COSMIC), we have discovered an internal gravity wave (IGW) activity and breaking hotspot in this region. Conditions supporting orographic wave sourcing and propagation were found. Other possible sources of wave activity in this region are listed. The reasons why this particular IGW activity hotspot was not discovered before as well as why the specific dynamics of this region have not been pointed out are discussed together with the weaknesses of using the mean potential energy as a wave activity proxy. Possible consequences of the specific dynamics in this region on the middle atmospheric dynamics and transport are outlined.

  13. An Active Region Model for Capturing Fractal Flow Patterns inUnsaturated Soils: Model Development

    SciTech Connect

    Liu, Hui-Hai; Zhang, R.; Bodvarsson, Gudmundur S.

    2005-06-11

    Preferential flow commonly observed in unsaturated soils allows rapid movement of solute from the soil surface or vadose zone to the groundwater, bypassing a significant volume of unsaturated soil and increasing the risk of groundwater contamination. A variety of evidence indicates that complex preferential patterns observed from fields are fractals. In this study, we developed a relatively simple active region model to incorporate the fractal flow pattern into the continuum approach. In the model, the flow domain is divided into active and inactive regions. Flow occurs preferentially in the active region (characterized by fractals), and inactive region is simply bypassed. A new constitutive relationship (the portion of the active region as a function of saturation) was derived. The validity of the proposed model is demonstrated by the consistency between field observations and the new constitutive relationship.

  14. VLA observations of solar active regions at 6 and 20 cm

    NASA Technical Reports Server (NTRS)

    Alissandrakis, C. E.; Kundu, M. R.; Shevgaonkar, K. R.

    1991-01-01

    High-resolution observations are presented of two active regions at 6 and 20 cm over a period of 5 days, together with H-alpha and photospheric magnetic fields. The large-scale emission at 20 cm is associated with the H-alpha plage. In one region the strongest source was over the neutral line, near the tip of an active-region filament, which indicates that the emission probably originated in small-scale coronal loops. In the second region the peak of the emission was near a well-developed sunspot. Neither region showed evidence of large-scale loops joining their preceding and following parts. Several other sources were observed at 20 cm; a source associated with an H-alpha plage region crossed by a filament and one associated with a small bipolar region are briefly discussed. The 6-cm emission from a well-developed spot showed clearly the characteristics expected from gyroresonance model computations.

  15. Regional vulnerability of the hippocampus to repeated motor activity deprivation.

    PubMed

    Faraji, Jamshid; Soltanpour, Nabiollah; Moeeini, Reza; Hosseini, Seyed Abedin; Pakdel, Shiva; Moharrerie, Alireza; Arjang, Kaveh; Soltanpour, Nasrin; Metz, Gerlinde A S

    2016-03-15

    Spontaneous vertical and horizontal exploratory movements are integral components of rodent behavior. Little is known, however, about the structural and functional consequences of restricted spontaneous exploration. Here, we report two experiments to probe whether restriction in vertical activity (rearing) in rats could induce neuro-hormonal and behavioral disturbances. Rearing movements in rats were deprived for 3h/day for 30 consecutive days by placing the animal into a circular tunnel task. Rats temporarily deprived of rearing behavior showed elevated plasma corticosterone levels but no detectable psychological distress and/or anxiety-related behavior within an elevated plus maze. However, rats emitted a greater number of 22-kHz ultrasonic vocalizations and spent significantly more time vocalizing than controls when deprived of their rearing behavior. Despite intact spatial performance within wet- and dry-land spatial tasks, rearing-deprived rats also exhibited a significant alteration in search strategies within both spatial tasks along with reduced volume and neuron number in the hippocampal subregion CA2. These data suggest a new approach to test the importance of free exploratory behavior in endocrine and structural manifestations. The results support a central role of the CA2 in spontaneous exploratory behavior and vulnerability to psychological stress. PMID:26723539

  16. A note on chromospheric fine structure at active region polarity boundaries.

    NASA Technical Reports Server (NTRS)

    Prata, S. W.

    1971-01-01

    High resolution H-alpha filtergrams from Big Bear Solar Observatory reveal that some filamentary features in active regions have fine structure and hence magnetic field transverse to the gross structure and the zero longitudinal field line. These features are distinct from the usual active region filament, in which fine structure, magnetic field, and filament are all parallel to the zero longitudinal field line. The latter occur on boundaries between regions of weaker fields, while the former occur at boundaries between regions of stronger field.

  17. Active region upflow plasma: its relation to small activity and the solar wind

    NASA Astrophysics Data System (ADS)

    Mandrini, Cristina H.; Culhane, J. Leonard; Cristiani, Germán; Vásquez, Alberto; Van Driel-Gesztelyi, Lidia; Baker, Deborah; Pick, Monique; Demoulin, Pascal; Nuevo, Federico

    Recent studies show that active region (AR) upflowing plasma, observed by the Hinode EUV Imaging Spectrometer (EIS), can gain access to open field lines and be released into the solar wind via magnetic interchange reconnection occurring below the source surface at magnetic null-points in pseudo-streamer configurations. When only one simple bipolar AR is present on the Sun and it is fully covered by the separatrix of a streamer, like AR 10978 on December 2007, it seems unlikely that the upflowing AR plasma could find its way into the slow solar wind. However, signatures of plasma with AR composition at 1 AU that appears to originate from the West of AR 10978 were recently found by Culhane and coworkers. We present a detailed topology analysis of AR 10978 based on a linear force-free magnetic field model at the AR scale, combined with a global PFSS model. This allows us, on one hand, to explain the variations observed in the upflows to the West of the AR as the result of magnetic reconnection at quasi-separatrix layers (QSLs). While at a global scale, we show that reconnection, occurring in at least two main steps, first at QSLs and later at a high-altitude coronal null-point, allows the AR plasma to get around the topological obstacle of the streamer separatrix and be released into the solar wind.

  18. Enzymatic activation of autotaxin by divalent cations without EF-hand loop region involvement.

    PubMed

    Lee, J; Jung, I D; Nam, S W; Clair, T; Jeong, E M; Hong, S Y; Han, J W; Lee, H W; Stracke, M L; Lee, H Y

    2001-07-15

    Autotaxin (ATX) is a recently described member of the nucleotide pyrophosphatase/phosphodiesterase (NPP) family of proteins with potent tumor cell motility-stimulating activity. Like other NPPs, ATX is a glycoprotein with peptide sequences homologous to the catalytic site of bovine intestinal alkaline phosphodiesterase (PDE) and the loop region of an EF-hand motif. The PDE active site of ATX has been associated with the motility-stimulating activity of ATX. In this study, we examined the roles of the EF-hand loop region and of divalent cations on the enzymatic activities of ATX. Ca(2+) or Mg(2+) was each demonstrated to increase the PDE activity of ATX in a concentration-dependent manner, whereas incubation of ATX with chelating agents abolished this activity, indicating a requirement for divalent cations. Non-linear regression analysis of enzyme kinetic data indicated that addition of these divalent cations increases reaction velocity predominantly through an effect on V(max.) Three mutant proteins, Ala(740)-, Ala(742)-, and Ala(751)-ATX, in the EF-hand loop region of ATX had enzymatic activity comparable to that of the wild-type protein. A deletion mutation of the entire loop region resulted in slightly reduced PDE activity but normal motility-stimulating activity. However, the PDE activity of this same deletion mutant remained sensitive to augmentation by cations, strongly implying that cations exert their effect by interactions outside of the EF-hand loop region. PMID:11389881

  19. Coronal Mass Ejection-driven Shocks and the Associated Sudden Commencements-sudden Impulses

    NASA Technical Reports Server (NTRS)

    Veenadhari, B.; Selvakumaran, R.; Singh, Rajesh; Maurya, Ajeet K.; Gopalswamy, N.; Kumar, Sushil; Kikuchi, T.

    2012-01-01

    Interplanetary (IP) shocks are mainly responsible for the sudden compression of the magnetosphere, causing storm sudden commencement (SC) and sudden impulses (SIs) which are detected by ground-based magnetometers. On the basis of the list of 222 IP shocks compiled by Gopalswamy et al., we have investigated the dependence of SC/SIs amplitudes on the speed of the coronal mass ejections (CMEs) that drive the shocks near the Sun as well as in the interplanetary medium. We find that about 91% of the IP shocks were associated with SC/SIs. The average speed of the SC/SI-associated CMEs is 1015 km/s, which is almost a factor of 2 higher than the general CME speed. When the shocks were grouped according to their ability to produce type II radio burst in the interplanetary medium, we find that the radio-loud (RL) shocks produce a much larger SC/SI amplitude (average approx. 32 nT) compared to the radio-quiet (RQ) shocks (average approx. 19 nT). Clearly, RL shocks are more effective in producing SC/SIs than the RQ shocks. We also divided the IP shocks according to the type of IP counterpart of interplanetary CMEs (ICMEs): magnetic clouds (MCs) and nonmagnetic clouds. We find that the MC-associated shock speeds are better correlated with SC/SI amplitudes than those associated with non-MC ejecta. The SC/SI amplitudes are also higher for MCs than ejecta. Our results show that RL and RQ type of shocks are important parameters in producing the SC/SI amplitude.

  20. [The athletes' ECG and the exercise related sudden cardiac death].

    PubMed

    Trachsel, Lukas-Daniel; Wilhelm, Matthias

    2015-05-01

    Regular physical activity induces structural, electrical and functional cardiac adaptations. The main challenge for the athletes' physician is to distinguish abnormal structural changes of the heart from training-induced adaptations (so-called “athlete's heart”). In athletes with underlying cardiac disease, physical activity may be a trigger, not the cause of exercise-induced tachyarrhythmia's and sudden cardiac death (SCD). To identify athletes with cardiac diseases and increased risk for an SCD, the European society of cardiology (ESC) recommends a pre-participation screening in elite athletes which was adopted by the Swiss society of sports medicine. The screening includes a specific medical history, cardiac auscultation and a resting ECG. Due to the high number of false-positive cases of athletes' ECGs based on traditional criteria, the ESC assessment criteria were adjusted to account for training-related changes of the ECG. The sensitivity and especially the specificity could be improved in the “revised Seattle criteria” in 2014. During the last years main attention has been shifted to the early repolarization pattern: additionally to (endurance-) training there is a clear association with male gender, ethnicity, changes in autonomic nervous system activity and high QRS-voltage criteria PMID:26098068

  1. Longitudinal variation of sudden commencement of geomagnetic storm at equatorial stations

    SciTech Connect

    Rastogi, R.G.

    1993-09-01

    The author reports the observation of a correlation between the strength of storm sudden commencements in the equatorial electrojet region with the equatorial electrojet current itself, as a function of daytime, latitude, and longitude. The author argues that electric fields generated at the magnetopause by interaction with solar wind plasma transmits to the polar region along field lines, and there converts to magnetic waves which rapidly propogate to equatorial regions in the conducting plasma between the ionosphere and the earth. The strength of the arrival fields is dependent upon the ionospheric conductivity at the particular location in question.

  2. Sudden Unexpected Death in Fetal Life Through Early Childhood.

    PubMed

    Goldstein, Richard D; Kinney, Hannah C; Willinger, Marian

    2016-06-01

    In March 2015, the Eunice Kennedy Shriver National Institute of Child Health and Human Development held a workshop entitled "Sudden Unexpected Death in Fetal Life Through Early Childhood: New Opportunities." Its objective was to advance efforts to understand and ultimately prevent sudden deaths in early life, by considering their pathogenesis as a potential continuum with some commonalities in biological origins or pathways. A second objective of this meeting was to highlight current issues surrounding the classification of sudden infant death syndrome (SIDS), and the implications of variations in the use of the term "SIDS" in forensic practice, and pediatric care and research. The proceedings reflected the most current knowledge and understanding of the origins and biology of vulnerability to sudden unexpected death, and its environmental triggers. Participants were encouraged to consider the application of new technologies and "omics" approaches to accelerate research. The major advances in delineating the intrinsic vulnerabilities to sudden death in early life have come from epidemiologic, neural, cardiac, metabolic, genetic, and physiologic research, with some commonalities among cases of unexplained stillbirth, SIDS, and sudden unexplained death in childhood observed. It was emphasized that investigations of sudden unexpected death are inconsistent, varying by jurisdiction, as are the education, certification practices, and experience of death certifiers. In addition, there is no practical consensus on the use of "SIDS" as a determination in cause of death. Major clinical, forensic, and scientific areas are identified for future research. PMID:27230764

  3. Sudden unexpected death, epilepsy and familial cardiac pathology.

    PubMed

    Eastaugh, A J; Thompson, T; Vohra, J K; O'Brien, T J; Winship, I

    2015-10-01

    We evaluated the prevalence of epilepsy in a cohort of patients who suffered a sudden unexpected death (SUDEP), and determined the proportion of the deaths that were related to an identifiable underlying familial cardiac pathology. Epilepsy is common in people who experience a sudden unexpected death, with approximately a quarter having identifiable familial electrophysiological abnormalities. Familial cardiac pathology may be an important cause of SUDEP. A retrospective evaluation was performed of 74 families that were referred to the Royal Melbourne Hospital Cardiac Genetic Clinic over a 5 year period for investigation following a family member's sudden, presumed cardiac, death. This state-wide referral clinic includes all patients who have died from a sudden unexpected death in whom the cause of death is unascertained. An epilepsy diagnosis was categorised as either definite, probable, possible or unlikely. The family members underwent comprehensive clinical evaluations and investigations in an attempt to identify a familial cardiac cause for the sudden unexpected death. Our findings suggest that systematic referral to a cardiac genetics service is warranted for the first degree relatives of people with epilepsy who experience a sudden unexplained death, for further evaluation and to identify those who are at higher risk for sudden death. Interventions may then be instituted to potentially reduce this risk. PMID:26195332

  4. Identification of a novel ovine LH-beta promoter region, which dramatically enhances its promoter activity.

    PubMed

    Aherrahrou, Redouane; Aherrahrou, Zouhair; Erdmann, Jeanette; Moumni, Mohieddine

    2015-01-01

    The luteinizing hormone beta subunit (LH-beta) gene plays a critical role in reproduction. In order to characterize and analyze the promoter region of LH-beta in sheep, a genomic library was constructed in phage lambda gt 10 and screened. A novel region of 1,224 bp upstream from the targeted LH-beta gene was identified. Blasting this sequence showed a perfect homology for the first 721 bp sequence with an upstream ovine LH-beta sequence in the database. However, the remaining 5'-503 bp showed no sequence matching. DNA from Moroccan breeds was isolated and the whole region was amplified and confirmed by sequencing. To further confirm the promoter activity of this region, an in vitro analysis using a luciferase assay was carried out. An increase in the promoter activity of the whole region was demonstrated compared to the empty vector. More interestingly, the unpublished region significantly enhanced the promoter activity compared to the known region alone. To predict putative transcription factor binding-sites (TFBSs), an in silico analysis was performed using the TFSEARCH program. The region features many TFBSs and contains two palindrome sequences of 17- and 18-bp. Taken together, a novel region was identified and confirmed in sheep which contained a promoter activity rich with binding sites for a putative regulatory element as shown in silico. PMID:26355566

  5. Damage Detection on Sudden Stiffness Reduction Based on Discrete Wavelet Transform

    PubMed Central

    Chen, Bo; Chen, Zhi-wei; Wang, Gan-jun; Xie, Wei-ping

    2014-01-01

    The sudden stiffness reduction in a structure may cause the signal discontinuity in the acceleration responses close to the damage location at the damage time instant. To this end, the damage detection on sudden stiffness reduction of building structures has been actively investigated in this study. The signal discontinuity of the structural acceleration responses of an example building is extracted based on the discrete wavelet transform. It is proved that the variation of the first level detail coefficients of the wavelet transform at damage instant is linearly proportional to the magnitude of the stiffness reduction. A new damage index is proposed and implemented to detect the damage time instant, location, and severity of a structure due to a sudden change of structural stiffness. Numerical simulation using a five-story shear building under different types of excitation is carried out to assess the effectiveness and reliability of the proposed damage index for the building at different damage levels. The sensitivity of the damage index to the intensity and frequency range of measurement noise is also investigated. The made observations demonstrate that the proposed damage index can accurately identify the sudden damage events if the noise intensity is limited. PMID:24991647

  6. Sudden Infant Death Syndrome and Residential Altitude

    PubMed Central

    Shore, Supriya; Bandle, Brian; Niermeyer, Susan; Bol, Kirk A.; Khanna, Amber

    2015-01-01

    BACKGROUND: Theories of sudden infant death syndrome (SIDS) suggest hypoxia is a common pathway. Infants living at altitude have evidence of hypoxia; however, the association between SIDS incidence and infant residential altitude has not been well studied. METHODS: We performed a retrospective cohort study by using data from the Colorado birth and death registries from 2007 to 2012. Infant residential altitude was determined by geocoding maternal residential address. Logistic regression was used to determine adjusted association between residential altitude and SIDS. We evaluated the impact of the Back to Sleep campaign across various altitudes in an extended cohort from 1990 to 2012 to assess for interaction between sleep position and altitude. RESULTS: A total of 393 216 infants born between 2007 and 2012 were included in the primary cohort (51.4% boys; mean birth weight 3194 ± 558 g). Overall, 79.6% infants resided at altitude <6000 feet, 18.5% at 6000 to 8000 feet, and 1.9% at >8000 feet. There were no meaningful differences in maternal characteristics across altitude groups. Compared with residence <6000 feet, residence at high altitude (>8000 feet), was associated with an adjusted increased risk of SIDS (odds ratio 2.30; 95% confidence interval 1.01–5.24). Before the Back to Sleep campaign, the incidence of SIDS in Colorado was 1.99/1000 live births and dropped to 0.57/1000 live births after its implementation. The Back to Sleep campaign had similar effect across different altitudes (P = .45). CONCLUSIONS: Residence at high altitude was significantly associated with an increased adjusted risk for SIDS. Impact of the Back to Sleep campaign was similar across various altitudes. PMID:26009621

  7. Postmortem imaging of sudden cardiac death.

    PubMed

    Michaud, Katarzyna; Grabherr, Silke; Jackowski, Christian; Bollmann, Marc Daniel; Doenz, Franceso; Mangin, Patrice

    2014-01-01

    Postmortem imaging is increasingly used in forensic practice in cases of natural deaths related to cardiovascular diseases, which represent the most common causes of death in developed countries. While radiological examination is generally considered to be a good complement for conventional autopsy, it was thought to have limited application in cardiovascular pathology. At present, multidetector computed tomography (MDCT), CT angiography, and cardiac magnetic resonance imaging (MRI) are used in postmortem radiological investigation of cardiovascular pathologies. This review presents the actual state of postmortem imaging for cardiovascular pathologies in cases of sudden cardiac death (SCD), taking into consideration both the advantages and limitations. The radiological evaluation of ischemic heart disease (IHD), the most frequent cause of SCD in the general population of industrialized countries, includes the examination of the coronary arteries and myocardium. Postmortem CT angiography (PMCTA) is very useful for the detection of stenoses and occlusions of coronary arteries but less so for the identification of ischemic myocardium. MRI is the method of choice for the radiological investigation of the myocardium in clinical practice, but its accessibility and application are still limited in postmortem practice. There are very few reports implicating postmortem radiology in the investigation of other causes of SCD, such as cardiomyopathies, coronary artery abnormalities, and valvular pathologies. Cardiomyopathies representing the most frequent cause of SCD in young athletes cannot be diagnosed by echocardiography, the most widely available technique in clinical practice for the functional evaluation of the heart and the detection of cardiomyopathies. PMCTA and MRI have the potential to detect advanced stages of diseases when morphological substrate is present, but these methods have yet to be sufficiently validated for postmortem cases. Genetically determined

  8. Case-control study of sudden infant death syndrome in Lithuania, 1997–2000

    PubMed Central

    Bubnaitienė, Vilija; Kalėdienė, Ramunė; Kėvalas, Rimantas

    2005-01-01

    Background To identify risk factors for sudden infant death syndrome relevant in Lithuania. Methods A nationwide case-control study surveying parents of 35 infants who died from sudden infant death syndrome during the period of 1997–2000 and parents of 145 control infants matched with SIDS infants for date of birth and for region of birth was carried out. Results Deaths incidence was greater in the warm period (60%) vs. cold period (40%). Prone and side sleeping positions both carried no increased risk of sudden infant death syndrome compared with supine because of a rare prone sleeping (4.1% of controls vs. 0% of dead infants) and more prevalent side than supine sleeping (84.8% of controls vs. 94.3% of dead infants) in the controls as well as the cases. Bed sharing for the whole night as a risk factor for sudden infant death syndrome has not been confirmed, either, as bed sharing was common only for the controls (13.8% of controls vs. 0% of dead infants). Routine sleeping environment factors such as heavy wrapping (≥4 togs) of an infant (odds ratio 8.49; 95% confidence interval 2.38 to 30.32), sleeping in a bassinet (4.22; 1.16 to 15.38) and maternal factors such as maternal education ≤12 years (4.48; 1.34 to 14.94), unplanned pregnancy (5.22; 1.49 to 18.18) and ≥2 previous live births (3.90; 1.00 to 15.10) were significantly associated with sudden infant death syndrome on multivariate analysis. Conclusion The results of this first population-based case-control study have shed some light on the epidemiology of the syndrome in Lithuania. Although the mortality of sudden infant death syndrome in Lithuania is not high, it might be lowered moreover by public informing about sudden infant death syndrome and related risk factors. Special attention must be paid to mothers with low education on potentially modifiable risk factors such as routine heavy wrapping of an infant during sleep, routine sleeping in a bassinet and unplanned pregnancy. PMID:16283946

  9. A STATISTICAL STUDY OF CORONAL ACTIVE EVENTS IN THE NORTH POLAR REGION

    SciTech Connect

    Sako, Nobuharu; Shimojo, Masumi; Watanabe, Tetsuya; Sekii, Takashi

    2013-09-20

    In order to study the relationship between characteristics of polar coronal active events and the magnetic environment in which such events take place, we analyze 526 X-ray jets and 1256 transient brightenings in the polar regions and in regions around the equatorial limbs. We calculate the occurrence rates of these polar coronal active events as a function of distance from the boundary of coronal holes, and find that most events in the polar quiet regions occur adjacent to and equatorward of the coronal hole boundaries, while events in the polar coronal holes occur uniformly within them. Based primarily on the background intensity, we define three categories of regions that produce activity: polar coronal holes, coronal hole boundary regions, and polar quiet regions. We then investigate the properties of the events produced in these regions. We find no significant differences in their characteristics, for example, length and lifetime, but there are differences in the occurrence rates. The mean occurrence rate of X-ray jets around the boundaries of coronal holes is higher than that in the polar quiet regions, equatorial quiet regions, and polar coronal holes. Furthermore, the mean occurrence rate of transient brightenings is also higher in these regions. We make comparison with the occurrence rates of emerging and canceling magnetic fields in the photosphere reported in previous studies, and find that they do not agree with the occurrence rates of transient brightenings found in this study.

  10. Differential activation of protein kinase A in various regions of myocardium during sepsis.

    PubMed

    Hsu, C; Yang, S L; Hsu, S P; Hsu, H K; Liu, M S

    1997-08-01

    Changes in the activities of protein kinase A (PKA) (cAMP-dependent protein kinase) in various regions of rat myocardium during different cardiodynamic phases of sepsis were studied in an attempt to understand the pathophysiology of cardiac dysfunction during sepsis. Sepsis was induced by cecal ligation and puncture (CLP). Experiments were divided into three groups: control, early sepsis, and late sepsis. Early and late sepsis refers to those animals sacrificed at 9 and 18 hr, respectively, after CLP. Cardiac PKA was extracted and partially purified by acid precipitation, ammonium sulfate fractionation, and DEAE-cellulose chromatography. PKA was eluted from DEAE-cellulose column with a linear NaCl gradient. Two types of PKA, Type I (eluted at low ionic strength) and Type II (eluted at high ionic strength), were collected, and their activities were determined based on the rate of incorporation of [gamma-32P]ATP into histone. Under physiological conditions, Type I PKA activities were unevenly distributed (left atrium > right atrium > pacemaker region > left ventricle > right ventricle > ventricular septum) while Type II PKA activities were evenly distributed among different regions of myocardium. During early sepsis, Type I PKA activities remained unchanged while Type II PKA activities were activated by 32 and 70% in right atrium and pacemaker regions, respectively. During late sepsis, Type I PKA activities were stimulated by 228% in ventricular septum while Type II PKA activities were not affected. These data demonstrate that different PKA activities exist in various regions of the myocardium and that PKA activities were preferentially activated in certain areas during the progression of sepsis. Since PKA plays an important role in the regulation of myocardial function and metabolism, the activation of PKA in different regions of myocardial during different stages of sepsis may contribute to the altered cardiac function during the progression of sepsis. PMID:9299285

  11. Heart failure therapy and sudden cardiac death prevention.

    PubMed

    Morgan, J M

    2004-12-01

    Primary prophylaxis of sudden cardiac death by implantable defibrillators is an accepted therapeutic strategy because sudden cardiac death is reduced by their use. However, many patients at risk of sudden cardiac death due to left ventricular systolic dysfunction also suffer heart failure symptoms. There is increasing evidence that the morbidity of heart failure can be alleviated by device therapy in which ventricular dysynchrony is improved by biventricular pacing. Both therapies in the same device can reduce both morbidity and mortality. Device therapy is an important new aspect in the field of heart failure management. PMID:15729212

  12. Unilateral sudden hearing loss: a rare symptom of Moyamoya disease.

    PubMed

    Gül, Fatih; Berçin, Sami; Müderris, Togay; Yalçıner, Gökhan; Ünal, Özkan; Kırış, Muzaffer

    2016-01-01

    A 38-year-old female patient experienced a sudden onset of unilateral sensorineural hearing loss due to Moyamoya disease. A detailed summary of audiological and neurological findings indicated that the sudden hearing loss might be due to Moyamoya disease resulting in occlusion of posterior and middle cerebral arteries. Intravenous prednisolone and trimetazidine dihydrochloride may improve hearing thresholds and speech understanding. To our knowledge, this is the first article in the literature reporting a case of sudden hearing loss as the first manifestation of Moyamoya disease in a young adult. PMID:26890714

  13. Doppler wavelength shifts of ultraviolet spectral lines in solar active regions

    NASA Technical Reports Server (NTRS)

    Feldman, U.; Doschek, G. A.; Cohen, L.

    1982-01-01

    Doppler shifts are measured for solar UV emission lines formed in the lower transition region of active regions. Doppler shifts in different regions at the same solar location, variations of Doppler shift with position of an active region on the disk, and variations of Doppler shift with time at the same solar location in the same active region were studied. Observations were made with the NRL slit spectrograph on Skylab. Excluding flare and flare-related phenomena, only redshifts are found whose magnitudes correspond to downflow velocities between about 4 and 17 km/s. Shifts are largest for lines formed between about 50,000 and 100,000 K, and are distinctly less for lines formed above 100,000 K. The shifts persist out to the limb, but not above it. There is no obvious change in redshift for lines measured at the same solar location over time intervals of about 20 minutes.

  14. Mapping brain region activity during chewing: a functional magnetic resonance imaging study.

    PubMed

    Onozuka, M; Fujita, M; Watanabe, K; Hirano, Y; Niwa, M; Nishiyama, K; Saito, S

    2002-11-01

    Mastication has been suggested to increase neuronal activities in various regions of the human brain. However, because of technical difficulties, the fine anatomical and physiological regions linked to mastication have not been fully elucidated. Using functional magnetic resonance imaging during cycles of rhythmic gum-chewing and no chewing, we therefore examined the interaction between chewing and brain regional activity in 17 subjects (aged 20-31 years). In all subjects, chewing resulted in a bilateral increase in blood oxygenation level-dependent (BOLD) signals in the sensorimotor cortex, supplementary motor area, insula, thalamus, and cerebellum. In addition, in the first three regions, chewing of moderately hard gum produced stronger BOLD signals than the chewing of hard gum. However, the signal was higher in the cerebellum and not significant in the thalamus, respectively. These results suggest that chewing causes regional increases in brain neuronal activities which are related to biting force. PMID:12407087

  15. Sudden cardiac and sudden unexpected death related to antipsychotics: A meta-analysis of observational studies.

    PubMed

    Salvo, F; Pariente, A; Shakir, S; Robinson, P; Arnaud, M; Thomas, Shl; Raschi, E; Fourrier-Réglat, A; Moore, N; Sturkenboom, M; Hazell On Behalf Of Investigators Of The Aritmo Consortium, L

    2016-03-01

    To estimate the risk of sudden cardiac death (SCD) or sudden unexpected death (SUD) related to individual antipsychotics, a meta-analysis of observational studies was performed. Adjusted odds ratio (OR) of SCD/SUD with 95% confidence intervals (CI) were extracted and pooled; heterogeneity was studied using Q statistic and I(2) index, and its potential causes (e.g., hERG blockade potency) explored using meta-regression. Two cohort (740,306 person-years) and four case-control (2,557 cases; 17,670 controls) studies, investigating nine antipsychotics, were included. Compared with nonusers, the risk was increased for quetiapine (OR = 1.72, 95% CI: 1.33-2.23), olanzapine (OR = 2.04, 1.52-2.74), risperidone (OR = 3.04, 2.39-3.86), haloperidol (OR = 2.97, 1.59-5.54), clozapine (OR = 3.67, 1.94-6.94), and thioridazine (OR = 4.58, 2.09-10.05). Heterogeneity was found (Q = 20.0, P = 0.01; I(2) = 60.0%), and the increasing mean hERG blockade potency (P = 0.01) accounted for 43% of this. The SCD/SUD risk differed between individual antipsychotics, and mean hERG blockade potency could be an explanatory factor. This should be considered when initiating antipsychotic treatment. PMID:26272741

  16. HELIOSEISMOLOGY OF PRE-EMERGING ACTIVE REGIONS. II. AVERAGE EMERGENCE PROPERTIES

    SciTech Connect

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

    2013-01-10

    We report on average subsurface properties of pre-emerging active regions as compared to areas where no active region emergence was detected. Helioseismic holography is applied to samples of the two populations (pre-emergence and without emergence), each sample having over 100 members, which were selected to minimize systematic bias, as described in Leka et al. We find that there are statistically significant signatures (i.e., difference in the means of more than a few standard errors) in the average subsurface flows and the apparent wave speed that precede the formation of an active region. The measurements here rule out spatially extended flows of more than about 15 m s{sup -1} in the top 20 Mm below the photosphere over the course of the day preceding the start of visible emergence. These measurements place strong constraints on models of active region formation.

  17. Complex active regions as the main source of extreme and large solar proton events

    NASA Astrophysics Data System (ADS)

    Ishkov, V. N.

    2013-12-01

    A study of solar proton sources indicated that solar flare events responsible for ≥2000 pfu proton fluxes mostly occur in complex active regions (CARs), i.e., in transition structures between active regions and activity complexes. Different classes of similar structures and their relation to solar proton events (SPEs) and evolution, depending on the origination conditions, are considered. Arguments in favor of the fact that sunspot groups with extreme dimensions are CARs are presented. An analysis of the flare activity in a CAR resulted in the detection of "physical" boundaries, which separate magnetic structures of the same polarity and are responsible for the independent development of each structure.

  18. Fragmentation of suddenly heated liquids in ICF reactors. Revision 1

    SciTech Connect

    Blink, J.A.; Hoover, W.G.

    1985-04-17

    Fragmentation of free liquids in Inertial Confinement Fusion reactors could determine the upper bound on reactor pulse rate because increased surface area will enhance the cooling and condensation of coolant ablated by the fusion x rays. Relaxation from the suddenly (neutron) heated state will move a liquid into the negative pressure region under the liquid-vapor P-V dome. The resulting expansion in a diverging geometry will hydrodynamically force the liquid to fragment, with vapor then forming from the new surfaces to fill the cavities. An energy minimization model is used to determine the fragment size that produces the least amount of non-fragment-center-of-mass energy; i.e., the sum of the surface and dilational kinetic energies. This model predicts fragmentation dependence on original system size and amount of isochoric heating as well as liquid density, Grueneisen parameter, surface tension, and sound speed. A two dimensional molecular dynamics code was developed to test the model at a microscopic scale for the Lennard-Jones fluid with its two adjustable constants chosen to represent lithium.

  19. Thermospheric meridional circulation during sudden stratospheric warming events

    NASA Astrophysics Data System (ADS)

    Laskar, F. I.; Duggirala, P. R.

    2014-12-01

    Oxygen dayglow emission intensities, at OI 557.7, OI 630.0, and OI 777.4 nm, over a low-latitude location showed systematic enhancements in intensities throughout the daytime hours during the four sudden stratospheric warming (SSW) events that occurred in the years 2010 - 2013. The arctic latitude lower thermospheric temperatures at around 120 km altitudes obtained from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument are found to be enhanced during SSW events and show a latitudinal gradient (temperature decreasing towards low-latitudes). Commensurately, the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) Doppler Interferometer (TIDI) measurements showed equatorward winds in the mesosphere lower thermosphere (MLT) altitudes over high latitudes during these events. Both, the high-latitude lower thermospheric temperature enhancements and the MLT region equatorward winds occur simultaneously with the observed enhancements in the OI dayglow emission intensities at all the wavelengths. From these observations and other supporting observational and modeling results it is proposed that a new cell of meridional circulation in the MLT winds is set up during SSW events, which enables transport of atomic oxygen from high-to-low latitudes. Such an additional contribution of oxygen density over low-latitudes interacts with daytime lower thermospheric dynamics and is attributed to be the cause for the observed enhancement in the oxygen daytime optical emission intensities over low-latitudes. These results will presented in the light of experimental evidence to such circulation alluded to by earlier simulation studies.

  20. ATM increases activation-induced cytidine deaminase activity at downstream S regions during class-switch recombination.

    PubMed

    Khair, Lyne; Guikema, Jeroen E J; Linehan, Erin K; Ucher, Anna J; Leus, Niek G J; Ogilvie, Colin; Lou, Zhenkun; Schrader, Carol E; Stavnezer, Janet

    2014-05-15

    Activation-induced cytidine deaminase (AID) initiates Ab class-switch recombination (CSR) in activated B cells resulting in exchanging the IgH C region and improved Ab effector function. During CSR, AID instigates DNA double-strand break (DSB) formation in switch (S) regions located upstream of C region genes. DSBs are necessary for CSR, but improper regulation of DSBs can lead to chromosomal translocations that can result in B cell lymphoma. The protein kinase ataxia telangiectasia mutated (ATM) is an important proximal regulator of the DNA damage response (DDR), and translocations involving S regions are increased in its absence. ATM phosphorylates H2AX, which recruits other DNA damage response (DDR) proteins, including mediator of DNA damage checkpoint 1 (Mdc1) and p53 binding protein 1 (53BP1), to sites of DNA damage. As these DDR proteins all function to promote repair and recombination of DSBs during CSR, we examined whether mouse splenic B cells deficient in these proteins would show alterations in S region DSBs when undergoing CSR. We find that in atm(-/-) cells Sμ DSBs are increased, whereas DSBs in downstream Sγ regions are decreased. We also find that mutations in the unrearranged Sγ3 segment are reduced in atm(-/-) cells. Our data suggest that ATM increases AID targeting and activity at downstream acceptor S regions during CSR and that in atm(-/-) cells Sμ DSBs accumulate as they lack a recombination partner. PMID:24729610

  1. A statistical study of active regions 1967-1981. [of sun

    NASA Technical Reports Server (NTRS)

    Tang, F.; Howard, R.; Adkins, J. M.

    1984-01-01

    A study is conducted of 15 years of active region data based on the Mount Wilson daily magnetograms in the interval 1967-1981. The analysis revealed the following: (1) The integral number of regions decreases exponentially with increasing region sizes, or N(A) = 4788 exp(-A/175) for the 15 years of data, where A is the area in square degrees and N(A) is the number of active regions with area equal to or greater than A; (2) the average area of active regions varies with the phase of the solar cycle. There are more larger regions during maximum than during minimum. (3) Regions in the north are 10 percent larger on average than those in the south during this interval. This coincides with a similar asymmetry in the total magnetic flux between the hemispheres. (4) Regions of all sizes and magnetic complexities show the same characteristic latitude variation with phase in the solar cycle. The largest regions, however, show a narrower latitude range.

  2. Two millennia of torrential activity reconstructed from alpine lake sediments: towards regional patterns of extreme precipitation changes

    NASA Astrophysics Data System (ADS)

    Wilhelm, B.; Arnaud, F.; Giguet-Covex, C.; Sabatier, P.; Crouzet, C.; Delannoy, J. J.

    2012-04-01

    In mountain areas extreme precipitation events trigger torrential floods, characterized by a sudden and intense rise of discharge causing large human and economic losses. Their frequency and/or intensity are expected to increase in the context of global warming. However, the relationship between such events and climate changes remains difficult to assess. Long-term geological records of intense events could enable to extend documented records beyond the observational data for a better understanding of local to regional flood hazard patterns in relation to past climatic changes and hence improving predictive models. In this context, lake sediment records appear a relevant archive as they are continuous records in which the identification of high-energy sediment layers allows to reconstruct flood calendar. In addition, the flood intensity can be reconstructed from the coarse fraction of each flood layer. Frequency and intensity of past torrential floods were thus reconstructed from four high-elevation lake records of the French Alps, in the framework of Pygmalion research program. Studied sites were selected along a north-south transect over this region to investigate the flooding responses to different climatic influences (westerlies in the north and Mediterranean influences in the south). High-resolution geochemical and sedimentological analyses were undertaken for an exhaustive identification of flood layers and several dating methods (short-lived radionuclides, 14C, correlation with historic events, paleomagnetism) were combined to reduce age uncertainties as much as possible. Over the entire French Alps, the torrential-flood frequency increases at a secular timescale during the cold period of the Little Ice Age (LIA; 1300-1900 AD). This increase seems in agreement with a regional high wetness, already described in the literature, possibly related to an increase in cyclonic activity. Superimposed to this secular trend, a pluri-decadal variability appears at

  3. MBE growth of active regions for electrically pumped, cw-operating GaSb-based VCSELs

    NASA Astrophysics Data System (ADS)

    Kashani-Shirazi, K.; Bachmann, A.; Boehm, G.; Ziegler, S.; Amann, M.-C.

    2009-03-01

    Electrically pumped, cw-operating, single-mode GaSb-based VCSELs are attractive light sources for trace-gas sensing systems using tunable diode laser absorption spectroscopy (TDLAS) [A. Vicet, D.A. Yarekha, A. Pérona, Y. Rouillard, S. Gaillard, Spectrochimica Acta Part A 58 (2002) 2405-2412]. Only recently, the first electrically pumped (EP) devices emitting at 2.325 μm in cw-mode at room temperature have been reported [A. Bachmann, T. Lim, K. Kashani-Shirazi, O. Dier, C. Lauer, M.-C. Amann, Electronics Letters 44(3) (2008) 202-203]. The fabrication of these devices employs the molecular beam epitaxy (MBE) growth of GaSb/AlAsSb-distributed Bragg mirrors, a multi-quantum-well active region made of AlGaAsSb/InGaAsSb and an InAsSb/GaSb-buried-tunnel junction. As VCSELs are usually driven under high injection rates, an optimum electrical design of active regions is essential for high-performance devices. In this paper we present an enhanced simulation of current flow in the active region under operation conditions. The calculation includes carrier transport by drift, diffusion and tunneling. We discuss different design criteria and material compositions for active regions. Active regions with various barrier materials were incorporated into edge emitter samples to evaluate their performance. Aluminum-containing barriers show better internal efficiency compared to active regions with GaSb as the barrier material.

  4. Sudden Stratospheric Warming of 2012-2013, its predictability, and its impact on the Northern Hemispheric winter

    NASA Astrophysics Data System (ADS)

    Tripathi, O. P.; Charlton-Perez, A. J.; Baldwin, M. P.; Charron, M.; Sigmond, M.; Eckermann, S. D.; Gerber, E. P.; Kuroda, Y.; Mizuta, R.; Jackson, D.; Lang, A.; Roff, G.; Son, S.; Kim, B.

    2013-12-01

    The stratospheric winter is characterized by strong circumpolar westerly winds and the region of colder polar cap temperatures called the polar vortex. During every other winter or so this polar winter circulation undergoes a Stratospheric Sudden Warming (SSW), a rapid deceleration resulting in easterly winds on the time scale of a few days a large increase in polar cap temperature. The predictability of these extreme stratospheric events are crucial for their impact on the tropospheric forecast on a timescale of one to two weeks. The Stratospheric Network on Assessment of Predictability (SNAP), a network of major operational forecasting centers, aims to understand the stratosphere-troposphere link and quantify how far in advance SSWs can be predicted and add skill to tropospheric forecasts. During the 2012-2013 winter, anomalous upward propagating planetary wave activity was observed during the second and third weak of December. Around 22nd of December there was a large eddy heat flux anomaly at 10 hPa. This was followed by a rapid deceleration of westerly circulation in the stratosphere starting around January 2, and within 3-4 days the circulation reversed on January 7, 2013. Within a couple of days the polar vortex split in two with a large increase in polar cap temperature. This stratospheric dynamical activity was followed by an equatorward shift of the tropospheric jet stream and a high pressure anomaly over North Atlantic, resulting in severe cold conditions in the UK and Northern Europe. Our current skill in predicting SSWs and therefore its consequential impact on tropospheric weather forecast is very limited due to the gap in proper understanding of stratosphere-troposphere coupling. SNAP has organized predictability experiments in different phases conducted by the operational centers. In this presentation we will show first results from SNAP for the Sudden Stratospheric Warming of January 2013. We will show how far in advance different models were able

  5. Prognostic Factors in Sudden Sensorineural Hearing Loss

    PubMed Central

    Atay, Gamze; Kayahan, Bahar; çınar, Betül çiçek; Saraç, Sarp; Sennaroğlu, Levent

    2016-01-01

    Background: Sudden sensorineural hearing loss (SSNHL) is still a complex and challenging process which requires clinical evidence regarding its etiology, treatment and prognostic factors. Therefore, determination of prognostic factors might aid in the selection of proper treatment modality. Aims: The aim of this study is to analyze whether there is correlation between SSNHL outcomes and (1) systemic steroid therapy, (2) time gap between onset of symptoms and initiation of therapy and (3) audiological pattern of hearing loss. Study Design: Retrospective chart review. Methods: Patients diagnosed at our clinic with SSNHL between May 2005 and December 2011 were reviewed. A detailed history of demographic features, side of hearing loss, previous SSNHL and/or ear surgery, recent upper respiratory tract infection, season of admission, duration of symptoms before admission and the presence of co-morbid diseases was obtained. Radiological and audiological evaluations were recorded and treatment protocol was assessed to determine whether systemic steroids were administered or not. Treatment started ≤5 days was regarded as “early” and >5 days as “delayed”. Initial audiological configurations were grouped as “upward sloping”, “downward sloping”, “flat” and “profound” hearing loss. Significant recovery was defined as thresholds improved to the same level with the unaffected ear or improved ≥30 dB on average. Slight recovery was hearing improvement between 10–30dB on average. Hearing recovery less than 10 dB was accepted as unchanged. Results: Among the 181 patients who met the inclusion criteria, systemic steroid was administered to 122 patients (67.4%), whereas 59 (32.6%) patients did not have steroids. It was found that steroid administration did not have any statistically significant effect in either recovered or unchanged hearing groups. Early treatment was achieved in 105 patients (58%) and 76 patients (42%) had delayed treatment. Recovery

  6. [Sudden hearing loss and the cranio-cervical junction].

    PubMed

    Bernal Sprekelsen, M; Hörmann, K; Weh, L

    1990-01-01

    Morphological alterations of the craniocervical junction as basilar impressions, a ponticulus posterior, an atlas assimilation, an intervertebral narrowing and spondylosis deformans, were found radiologically in patients with sudden hearing loss. There were no radiological differences to a healthy population. No relationship could be established between static morphological changes of the craniocervical junction of the upper cervical spine and the sudden hearing loss. However, there was a statistically significant reduction of the mobility in the upper cervical spine in patients suffering from sudden hearing loss. Very high standard deviations in the atlanto-occipital and the atlanto-odontoid joints are interpreted as hyper- as well as hypomobile joints. These results indicate a possible correlation between sudden hearing loss and a functional pathology of the craniocervical junction. PMID:2221307

  7. [Sudden death following a single oral administration of haloperidol].

    PubMed

    Remijnse, P L; Eeckhout, A M; van Guldener, C

    2002-04-20

    A 39-year-old man was admitted with myasthenia, alcoholic hepatitis and electrolyte abnormalities due to an inadequate nutritional state. On admission the ECG showed a prolonged QTc interval (0.46 s). The patient was treated with intravenous fluid and supplementary vitamins and minerals. On the third day of admission the patient developed a delirium, partly due to alcohol withdrawal, and was therefore treated with oxazepam 50 mg 3 times daily and a single dose of haloperidol 5 mg. One hour after ingesting haloperidol, the patient suddenly succumbed and resuscitation was not successful. The autopsy revealed a cardiomyopathy but no explanation for the sudden death. Due to the temporal relationship between the ingestion of haloperidol and this sudden death, we assume that haloperidol induced a fatal arrhythmia in the presence of a preexisting prolonged repolarisation time. To the best of our knowledge, sudden death after a single oral therapeutic dose of haloperidol has not previously been described. PMID:11998355

  8. Psychosocial Aspects of the Sudden Infant Death Syndrome ("Cot Death").

    ERIC Educational Resources Information Center

    Bluglass, Kerry

    1981-01-01

    Reviews literature on reactions of parents and siblings to Sudden Infant Death Syndrome (SIDS). The prospects for prolonged, adverse reactions are considered, and professional concerns regarding abnormal adaptation are noted. (Author/DB)

  9. HARPs: Tracked Active Region Patch Data Product from SDO/HMI

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    We describe an HMI data product consisting of tracked magnetic features on the scale of solar active regions, abbreviated HARPs (HMI Active Region Patches). The HARP data series has been helpful for subsetting individual active regions, for development of near-real-time (NRT) space weather indices for individual active regions, and for defining closed magnetic structures for computationally-intensive algorithms like vector field disambiguation. The data series builds upon the 720s cadence activity masks, which identify large-scale instantaneously-observed magnetic features. Using these masks as a starting point, large spatially-coherent structures are identified using convolution with a longitudinally-extended kernel on a spherical domain. The resulting set of identified regions is then tracked from image to image. The metric for inter-image association is area of overlap between the best current estimate of AR location, as predicted by temporally extrapolating each currently tracked object, and the set of instantaneously-observed magnetic structures. Once completed tracks have been extracted, they are made into a standardized HARP data series by finding the smallest constant-angular-velocity box, of constant width in latitude and longitude, that encompasses all appearances of the active region. This data product is currently available, in definitive and near-real-time forms, with accompanying region-strength, location, and NOAA-AR metadata, on HMI's Joint Science Operations Center (JSOC) data portal.; HARP outlines for three days (2001 February 14, 15, and 16, 00:00 TAI, flipped N-S, selected from the 12-minute cadence original data product). HARPs are shown in the same color (some colors repeated) with a thin white box surrounding each HARP. HARPs are tracked and associated from image to image. HARPs, such as the yellow one in the images above, need not be connected regions. Merges and splits, such as the light blue region, are accounted for automatically.

  10. The polar Sudden Stratospheric Warming (SSW) and it's possible manifestations in the equatorial Mesosphere-Thermosphere-Ionosphere

    NASA Astrophysics Data System (ADS)

    Pant, Tarun

    In this study, the variations in daytime mesopause temperature and the Equatorial Electrojet over equator during Sudden Stratospheric Warming (SSW) events over high latitudes have been investigated. To reflect upon the stratospheric conditions NCEP-NCAR reanalysis data have also been used. This study indicates a possible dynamical coupling between the two regions through the planetary wave activity. The amplified wave signatures of quasi-16 day period are seen in the equatorial mesopause temperature and zonal mean polar stratospheric temperature (at 10 hPa) during the course of SSW. The possibility that the planetary waves over the polar stratosphere, which play an important role in the generation of SSW, could also have contribu-tion from the tropics has been indicated through numerical simulations in the past [Dunkerton, 1981], but due to the paucity of global measurements it could not be established unequivocally. These simulations also indicated the presence of a zero-wind line whose real counterparts were not observed in the atmosphere. The NCEP-NCAR reanalysis of stratospheric wind and tem-peratures clearly shows that (i) a dynamical feature similar to the zero-wind line appears over the tropics 60 days prior to the major warming and progresses poleward and, (ii) enhanced PW activity is seen almost simultaneously. This study shows that the recent SSW events had tropical associations. Further, favored occurrences of Equatorial Counter Electrojets (CEJs) with a quasi 16-day periodicity over Trivandrum (8.5oN, 76.5oE, 0.5oN diplat.) in association with the polar Stratospheric Sudden Warming (SSW) events are presented. It is seen that, the stratospheric temperature at 30 km over Trivandrum showed a sudden cooling prior to the SSW and the first bunch of CEJs occurred around this time. Stratospheric zonal mean zonal wind at 30 km exhibited a distinctly different pattern during the SSW period. These circula-tion changes are proposed to be conducive for the upward

  11. The polar Sudden Stratospheric Warming (SSW) and it's possible manifestations in the equatorial Mesosphere-Thermosphere-Ionosphere

    NASA Astrophysics Data System (ADS)

    Pant, Tarun; Vineeth, C.; Sridharan, R.

    In this study, the variations in daytime mesopause temperature and the Equatorial Electrojet over equator during Sudden Stratospheric Warming (SSW) events over high latitudes have been investigated. To reflect upon the stratospheric conditions NCEP-NCAR reanalysis data have also been used. This study indicates a possible dynamical coupling between the two regions through the planetary wave activity. The amplified wave signatures of quasi-16 day period are seen in the equatorial mesopause temperature and zonal mean polar stratospheric temperature (at 10 hPa) during the course of SSW. The possibility that the planetary waves over the polar stratosphere, which play an important role in the generation of SSW, could also have contribution from the tropics has been indicated through numerical simulations in the past [Dunkerton, 1981], but due to the paucity of global measurements it could not be established unequivocally. These simulations also indicated the presence of a zero-wind line whose real counterparts were not observed in the atmosphere. The NCEP-NCAR reanalysis of stratospheric wind and temperatures clearly shows that (i) a dynamical feature similar to the zero-wind line appears over the tropics 60 days prior to the major warming and progresses poleward and, (ii) enhanced PW activity is seen almost simultaneously. This study shows that the recent SSW events had tropical associations. Further, favored occurrences of Equatorial Counter Electrojets (CEJs) with a quasi 16-day periodicity over Trivandrum (8.5oN, 76.5oE, 0.5oN diplat.) in association with the polar Stratospheric Sudden Warming (SSW) events are presented. It is seen that, the stratospheric temperature at 30 km over Trivandrum showed a sudden cooling prior to the SSW and the first bunch of CEJs occurred around this time. Stratospheric zonal mean zonal wind at 30 km exhibited a distinctly different pattern during the SSW period. These circulation changes are proposed to be conducive for the upward

  12. Global burden of Sudden Cardiac Death and insights from India

    PubMed Central

    Rao, B. Hygriv

    2014-01-01

    Sudden Cardiac death (SCD) is a major clinical event causing adverse impact on global economy. This review summarizes the available epidemiological data on SCD from different parts of the world. It contrasts the Indian and global perception on the issues influencing data collection, burden of SCD and sudden deaths occurring following Myocardial Infarction. The differences in data from India and rest of the world are highlighted. PMID:24568824

  13. Regional activation within the vastus medialis in stimulated and voluntary contractions.

    PubMed

    Gallina, Alessio; Ivanova, Tanya D; Garland, S Jayne

    2016-08-01

    This study examined the contribution of muscle fiber orientation at different knee angles to regional activation identified with high-density surface electromyography (HDsEMG). Monopolar HDsEMG signals were collected using a grid of 13 × 5 electrodes placed over the vastus medialis (VM). Intramuscular electrical stimulation was used to selectively activate two regions within VM. The distribution of EMG responses to stimulation was obtained by calculating the amplitude of the compound action potential for each channel; the position of the peak amplitude was tracked across knee angles to describe shifts of the active muscle regions under the electrodes. In a separate experiment, regional activation was investigated in 10 knee flexion-extension movements against a fixed resistance. Intramuscular stimulation of different VM regions resulted in clear differences in amplitude distribution along the columns of the electrode grid (P < 0.001); changes in knee angle resulted in consistent shifts along the rows (P < 0.01) and negligible shifts along the columns of the electrode grid. Regional VM activation was identified in dynamic movement, with distal shifts of the EMG distribution in the eccentric phase of the movement (P < 0.05) and at more flexed knee angles (P < 0.05). HDsEMG was used to describe regional activation across the VM that was not attributable to anatomic factors. Changes in muscle fiber orientation associated with knee joint angle mainly influence the amplitude distribution along the fiber direction. Future studies are needed to understand possible functional roles for regional activation within the VM in dynamic tasks. PMID:27365281

  14. Regional activation of rapid onset vasodilatation in mouse skeletal muscle: regulation through α-adrenoreceptors.

    PubMed

    Moore, Alex W; Bearden, Shawn E; Segal, Steven S

    2010-09-01

    Exercise onset entails motor unit recruitment and the initiation of vasodilatation. Dilatation can ascend the arteriolar network to encompass proximal feed arteries but is opposed by sympathetic nerve activity, which promotes vasoconstriction and inhibits ascending vasodilatation through activating α-adrenoreceptors. Whereas contractile activity can antagonize sympathetic vasoconstriction, more subtle aspects of this interaction remain to be defined. We tested the hypothesis that constitutive activation of α-adrenoreceptors governs blood flow distribution within individual muscles. The mouse gluteus maximus muscle (GM) consists of Inferior and Superior regions. Each muscle region is supplied by its own motor nerve and feed artery with an anastomotic arteriole (resting diameter 25 microm) that spans both muscle regions. In anaesthetized male C57BL/6J mice (3-5 months old), the GM was exposed and superfused with physiological saline solution (35 degrees C; pH 7.4). Stimulating the inferior gluteal motor nerve (0.1 ms pulse, 100 Hz for 500 ms) evoked a brief tetanic contraction and produced rapid (<1 s) onset vasodilatation (ROV; diameter change, 10 +/- 1 μm) of the anastomotic arteriole along the active (Inferior) muscle region but not along the inactive (Superior) region (n = 8). In contrast, microiontophoresis of acetylcholine (1 μm micropipette tip, 1 μA, 500 ms) initiated dilatation that travelled along the anastomotic arteriole from the Inferior into the Superior muscle region (diameter change, 5 +/- 2 μm). Topical phentolamine (1 μm) had no effect on resting diameter but this inhibition of α-adrenoreceptors enabled ROV to spread along the anastomotic arteriole into the inactive muscle region (dilatation, 7 +/- 1 μm; P < 0.05), where remote dilatation to acetylcholine then doubled (P < 0.05). These findings indicate that constitutive activation of α-adrenoreceptors in skeletal muscle can restrict the spread of dilatation within microvascular resistance

  15. Different metabolic activity in placental and reflected regions of the human amniotic membrane.

    PubMed

    Banerjee, Asmita; Weidinger, Adelheid; Hofer, Martin; Steinborn, Ralf; Lindenmair, Andrea; Hennerbichler-Lugscheider, Simone; Eibl, Johann; Redl, Heinz; Kozlov, Andrey V; Wolbank, Susanne

    2015-11-01

    Cells of the human amniotic membrane (hAM) have stem cell characteristics with low immunogenicity and anti-inflammatory properties. While hAM is an excellent source for tissue engineering, so far, its sub-regions have not been taken into account. We show that placental and reflected hAM differ distinctly in morphology and functional activity, as the placental region has significantly higher mitochondrial activity, however significantly less reactive oxygen species. Since mitochondria may participate in processes such as cell rescue, we speculate that amniotic sub-regions may have different potential for tissue regeneration, which may be crucial for clinical applications. PMID:26386652

  16. A synoptic study of Sudden Phase Anomalies (SPA's) effecting VLF navigation and timing

    NASA Technical Reports Server (NTRS)

    Swanson, E. R.; Kugel, C. P.

    1973-01-01

    Sudden phase anomalies (SPA's) observed on VLF recordings are related to sudden ionospheric disturbances due to solar flares. Results are presented for SPA statistics on 500 events observed in New York during the ten year period 1961 to 1970. Signals were at 10.2kHz and 13.6kHz emitted from the OMEGA transmitters in Hawaii and Trinidad. A relationship between SPA frequency and sun spot number was observed. For sun spot number near 85, about one SPA per day will be observed somewhere in the world. SPA activity nearly vanishes during periods of low sun spot number. During years of high solar activity, phase perturbations observed near noon are dominated by SPA effects beyond the 95th percentile. The SPA's can be represented by a rapid phase run-off which is approximately linear in time, peaking in about 6 minutes, and followed by a linear recovery. Typical duration is 49 minutes.

  17. Sudden unexpected death in epilepsy: Fatal post-ictal respiratory and arousal mechanisms

    PubMed Central

    Sowers, Levi P.; Massey, Cory A.; Gehlbach, Brian K.; Granner, Mark A.; Richerson, George B.

    2015-01-01

    Sudden unexplained death in epilepsy (SUDEP) is the cause of premature death of up to 17% of all patients with epilepsy and as many as 50% with chronic refractory epilepsy. However, SUDEP is not widely recognized to exist. The etiology of SUDEP remains unclear, but growing evidence points to peri-ictal respiratory, cardiac, or autonomic nervous system dysfunction. How seizures affect these systems remains uncertain. Here we focus on respiratory mechanisms believed to underlie SUDEP. We highlight clinical evidence that indicates peri-ictal hypoxemia occurs in a large percentage of patients due to central apnea, and identify the proposed anatomical regions of the brain governing these responses. In addition, we discuss animal models used to study peri-ictal respiratory depression. We highlight the role 5-HT neurons play in respiratory control, chemoreception, and arousal. Finally, we discuss the evidence that 5-HT deficits contribute to SUDEP and sudden infant death syndrome and the striking similarities between the two. PMID:23707877

  18. On the origin and suddenness of absences in genetic absence models.

    PubMed

    van Luijtelaar, Gilles; Sitnikova, Evgenia; Littjohann, Annika

    2011-04-01

    The origin of spike-wave discharges (SWDs), typical for absences, has been debated for at least half a century. While most classical views adhere to a thalamic oscillatory machinery and an active role of the cortex in modifying normal oscillations into pathological SWDs, recent studies in genetic models such as WAG/Rij and GAERS rats have challenged this proposal. It seems now well established that SWDs originate from the deep layers of the somatosensory cortex, that the activity quickly spreads over the cortex and invades the thalamus. The reticular thalamic nucleus and other thalamic nuclei provide a resonance circuitry for the amplification, spreading and entrainment of the SWDs. Conclusive evidence has been found that the changed functionality of HCN1 channels is a causative factor for the changes in local excitability and age-dependent increase in SWD. Furthermore, upregulation of two subtypes of Na+ channels, reduction of GABAB and mGlu 2/3 receptors might also play a role in the local increased excitability in WAG/Rij rats. Signal analytical studies have also challenged the view that SWDs occur suddenly from a normal background EEG. SWDs are recruited cortical responses and they develop from increasing associations within and between cortical layers and subsequently subcortical regions, triggered by the simultaneous occurrence of theta and delta precursor activity in the cortex and thalamus in case both structures are in a favorable condition, and increased directional coupling between cortex and thalamus. It is hypothesized that the cortex is the driving force throughout the whole SWD and is also responsible for its end. PMID:21675598

  19. Community study of the causes of "natural" sudden death.

    PubMed Central

    Thomas, A. C.; Knapman, P. A.; Krikler, D. M.; Davies, M. J.

    1988-01-01

    Three hundred and fifty cases of "natural" sudden death within six hours of onset of symptoms in people ranging in age from 18 to 69 years in Wandsworth were studied using a detailed necropsy protocol to determine the cause of death. Sudden death occurred in 28 (8%) Asians and blacks, but because of the small number they were excluded from the study, leaving 322 cases. Ischaemic heart disease accounted for 189 (59%) of the 322 sudden deaths (155 (65%) men; 34 (41%) women) and no proportional increase in instantaneous compared with non-instantaneous sudden death was found. Non-ischaemic cardiac disease was the cause of sudden death in 24 cases (7.5%). Non-cardiac disease included pulmonary emboli, aortic aneurysms, and intracerebral haemorrhage and caused 89 (27.6%) deaths. Alcohol was the cause of nine deaths (2.8%) and in 11 (3.4%) cases (six men and five women) no cause of death was found. This study shows that although ischaemic heart disease is the single largest cause of sudden natural death there are other major causes. Images p1456-a PMID:3147014

  20. Sudden cardiac death from the perspective of coronary artery disease.

    PubMed

    Sara, Jaskanwal D; Eleid, Mackram F; Gulati, Rajiv; Holmes, David R

    2014-12-01

    Sudden cardiac death accounts for approximately 50% of all deaths attributed to cardiovascular disease in the United States. It is most commonly associated with coronary artery disease and can be its initial manifestation or may occur in the period after an acute myocardial infarction. Decreasing the rate of sudden cardiac death requires the identification and treatment of at-risk patients through evidence-based pharmacotherapy and interventional strategies aimed at primary and secondary prevention. For this review, we searched PubMed for potentially relevant articles published from January 1, 1970, through March 1, 2014, using the following key search terms: sudden cardiac death, ischemic heart disease, coronary artery disease, myocardial infarction, and cardiac arrest. Searches were enhanced by scanning bibliographies of identified articles, and those deemed relevant were selected for full-text review. This review outlines various mechanisms for sudden cardiac death in the setting of coronary artery disease, describes risk factors for sudden cardiac death, explores the management of cardiac arrest, and outlines optimal practice for the monitoring and treatment of patients after an acute ST-segment elevation myocardial infarction to decrease the risk of sudden death. PMID:25440727

  1. Multiwavelength observations of a preflare solar active region using the VLA

    NASA Technical Reports Server (NTRS)

    Kundu, M. R.; Shevgaonkar, R. K.

    1985-01-01

    A preflare active region was studied using the Very Large Array at 2, 6, and 20 cm. At 2 cm the region is composed of two components located in regions of opposite polarity. Both components are preheated prior to the impulsive onset of a flare. However, one component develops new structures during preburst phase, and the burst occurs in this location. It is believed that the new structures represent emerging flux regions which interact with an overlying loop to produce a neutral sheet, which ultimately is responsible for triggering the flare.

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

    PubMed Central

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

    2014-01-01

    MAG4 is a technique of forecasting an active region's rate of production of major flares in the coming few days from a free magnetic energy proxy. We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region's major-flare productivity from alternative observed aspects of the active region. We demonstrate the method by measuring the difference in performance between the “Present MAG4” technique and each of three alternative techniques, called “McIntosh Active-Region Class,” “Total Magnetic Flux,” and “Next MAG4.” We do this by using (1) the MAG4 database of magnetograms and major flare histories of sunspot active regions, (2) the NOAA table of the major-flare productivity of each of 60 McIntosh active-region classes of sunspot active regions, and (3) five technique performance metrics (Heidke Skill Score, True Skill Score, Percent Correct, Probability of Detection, and False Alarm Rate) evaluated from 2000 random two-by-two contingency tables obtained from the databases. We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4). Key Points Quantitative comparison of performance of pairs of forecasting techniques Next MAG4 forecasts major flares more accurately than Present MAG4 Present MAG4 forecast outperforms McIntosh AR Class and total magnetic flux PMID:26213517

  3. Magnetic flux transport of decaying active regions and enhanced magnetic network. [of solar supergranulation

    NASA Technical Reports Server (NTRS)

    Wang, Haimin; Zirin, Harold; Ai, Guoxiang

    1991-01-01

    Several series of coordinated observations on decaying active regions and enhanced magnetic network regions on the sun were carried out jointly at Big Bear Solar Observatory and at the Huairou Solar Observing Station of the Bejing Astronomical Observatory in China. The magnetic field evolution in several regions was followed closely for three to seven days. The magnetic flux transport from the remnants of decayed active regions was studied, along with the evolution and lifetime of the magnetic network which defines the boundaries of supergranules. The magnetic flux transport in an enhanced network region was studied in detail and found to be negative. Also briefly described are some properties of moving magnetic features around a sunspot. Results of all of the above studies are presented.

  4. MAGNETIC FIELD TOPOLOGY AND THE THERMAL STRUCTURE OF THE CORONA OVER SOLAR ACTIVE REGIONS

    SciTech Connect

    Schrijver, Carolus J.; DeRosa, Marc L.; Title, Alan M.

    2010-08-20

    Solar extreme ultraviolet (EUV) images of quiescent active-region coronae are characterized by ensembles of bright 1-2 MK loops that fan out from select locations. We investigate the conditions associated with the formation of these persistent, relatively cool, loop fans within and surrounding the otherwise 3-5 MK coronal environment by combining EUV observations of active regions made with TRACE with global source-surface potential-field models based on the full-sphere photospheric field from the assimilation of magnetograms that are obtained by the Michelson Doppler Imager (MDI) on SOHO. We find that in the selected active regions with largely potential-field configurations these fans are associated with (quasi-)separatrix layers (QSLs) within the strong-field regions of magnetic plage. Based on the empirical evidence, we argue that persistent active-region cool-loop fans are primarily related to the pronounced change in connectivity across a QSL to widely separated clusters of magnetic flux, and confirm earlier work that suggested that neither a change in loop length nor in base field strengths across such topological features are of prime importance to the formation of the cool-loop fans. We discuss the hypothesis that a change in the distribution of coronal heating with height may be involved in the phenomenon of relatively cool coronal loop fans in quiescent active regions.

  5. Rendering Three-Dimensional Solar Coronal Structures of Active Region 8227

    NASA Technical Reports Server (NTRS)

    Gary, G. A.; Alexander, D. A.

    1999-01-01

    Coronal X-ray and EUV synthesized images are constructed of Active Region 8227 (May-June 1996) and are compared with Yohkoh/SXT, SOHO/EIT, and TRACE observations. Using the rendering technique of Gary (1997) and Alexander, Gary, and Thompson (1998), specific geometric and physical models are used to integrated the plasma emission along the line of sight to obtain a rendered image. The specific instrumental profiles are convolved in the integration process as well as specific heating functions. We analyze coronal X-ray and EUV structures by constructing synthesized image and comparison with observations provide test of specific physical models. We investigate how different pressure distributions within the active region loop system affect the emission characteristics and compare the various results with coronal observations. We investigate how the different heating functions in the active region are reflected in the effect of overall structure of the region. Specific heating rates are tested.

  6. 50 CFR 217.151 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... activity and specified geographical region. (a) Regulations in this subpart apply only to Port Dolphin Energy LLC (Port Dolphin) and those persons it authorizes to conduct activities on its behalf for the... incidental to construction and operation of the Port Dolphin Deepwater Port (Port). (b) The taking of...

  7. 50 CFR 217.151 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... activity and specified geographical region. (a) Regulations in this subpart apply only to Port Dolphin Energy LLC (Port Dolphin) and those persons it authorizes to conduct activities on its behalf for the... incidental to construction and operation of the Port Dolphin Deepwater Port (Port). (b) The taking of...

  8. Hepatitis C virus nonstructural region 5A protein is a potent transcriptional activator.

    PubMed Central

    Kato, N; Lan, K H; Ono-Nita, S K; Shiratori, Y; Omata, M

    1997-01-01

    The hepatitis C virus (HCV) nonstructural region 5A (NS5A) protein, without its 146 amino-terminal amino acids and fused to the DNA-binding domain of GAL4, strongly activates transcription in yeast and human hepatoma cells. Transcriptional activation by the HCV NS5A protein may play a role in viral replication and hepatocarcinogenesis. PMID:9343247

  9. 50 CFR 217.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Operation and Maintenance of the Neptune Liquefied Natural Gas Facility Off Massachusetts § 217.170 Specified activity and specified geographical region. (a) Regulations in this subpart apply only to Neptune LNG LLC (Neptune) and those persons it authorizes to conduct activities on its behalf for the...

  10. 50 CFR 217.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Operation and Maintenance of the Neptune Liquefied Natural Gas Facility Off Massachusetts § 217.170 Specified activity and specified geographical region. (a) Regulations in this subpart apply only to Neptune LNG LLC (Neptune) and those persons it authorizes to conduct activities on its behalf for the...

  11. 50 CFR 217.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Operation and Maintenance of the Neptune Liquefied Natural Gas Facility Off Massachusetts § 217.170 Specified activity and specified geographical region. (a) Regulations in this subpart apply only to Neptune LNG LLC (Neptune) and those persons it authorizes to conduct activities on its behalf for the...

  12. 50 CFR 217.170 - Specified activity and specified geographical region.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Operation and Maintenance of the Neptune Liquefied Natural Gas Facility Off Massachusetts § 217.170 Specified activity and specified geographical region. (a) Regulations in this subpart apply only to Neptune LNG LLC (Neptune) and those persons it authorizes to conduct activities on its behalf for the...

  13. Medical Image Segmentation Based on a Hybrid Region-Based Active Contour Model

    PubMed Central

    Liu, Tingting; Xu, Haiyong; Liu, Zhen; Zhao, Yiming; Tian, Wenzhe

    2014-01-01

    A novel hybrid region-based active contour model is presented to segment medical images with intensity inhomogeneity. The energy functional for the proposed model consists of three weighted terms: global term, local term, and regularization term. The total energy is incorporated into a level set formulation with a level set regularization term, from which a curve evolution equation is derived for energy minimization. Experiments on some synthetic and real images demonstrate that our model is more efficient compared with the localizing region-based active contours (LRBAC) method, proposed by Lankton, and more robust compared with the Chan-Vese (C-V) active contour model. PMID:25028593

  14. Special Issues Related to Hematopoietic Stem Cell Transplantation in the Eastern Mediterranean Region and the First Regional Activity Report

    PubMed Central

    Aljurf, Mahmoud; Zaidi, Syed Z; El Solh, Hassan; Hussain, Fazal; Ghavamzadeh, Ardeshir; Mahmoud, Hossam Kamel; Shamsi, Tahir; Othman, Tarek Ben; Sarhan, Mahmoud M.; Dennison, David; Ibrahim, Ahmad; Benchekroun, Said; Chaudhri, Naeem; Labar, Boris; Horowitz, Mary; Niederwieser, Dietger; Gratwohl, Alois

    2012-01-01

    Although several centers are now performing allogeneic HSCT in the Eastern Mediterranean (EM) region, the availability is still limited. Special issues including compatible donor availability and potential for alternate donor programs are discussed. In comparison to Europe & North America, differences in pattern of diseases and pre-HSCT general status particularly for patients with BM failure are described. Other differences including high seropositivity for CMV, Hepatitis B and C infection and specific observations about GVHD with its relation to genetically homogeneous community are also discussed. We report that a total of 17 HSCT programs (performing 5 or more HSCTs annually) exist in 9 countries of the EM region. Only 6 programs are currently reporting to EBMT or IBMTR. A total of 7617 HSCTs have been performed by these programs including 5701 allogeneic HSCTs. Due to low HSCT team density (1.5583 teams/10 million inhabitants vs. 14.4333 in Europe) and very low HSCT team distribution (0.2729 teams/10,000 sq km area vs. <1 to 6 teams in Europe). GNI/capita had no clear association with low HSCT activity; however improvement in infrastructure & formation of EM regional HSCT registry are needed. PMID:19043456

  15. Historically largest geomagnetic sudden commencement (SC) since 1868

    NASA Astrophysics Data System (ADS)

    Araki, Tohru

    2014-12-01

    Being stimulated by the previously reported large amplitude (202 nT at Kakioka) geomagnetic sudden commencement (SC) on 24 March 1991, we searched larger amplitude SCs in the past. We tried to collect old magnetograms and used the list of SC observed at Kakioka (27.5° gm.lat.) for the period 1924 to 2013 and Colaba (10.5°)-Alibag (10.3°) for 1868 to 1967. We found that the largest amplitude SC occurred on 24 March (the same day as 1991 SC), 1940. The H-component amplitude is larger than 273 nT at Kakioka and 310 nT at Alibag. We could also obtain the copy of the magnetogram of Cape Town (-33.3°) which shows 164 nT amplitude. The statistical analysis shows that the occurrence rate of SCs is less than 5% for amplitude larger than 50 nT and less than 1% for amplitude larger than 100 nT at both Kakioka and Alibag. Large amplitude SCs tend to occur during the declining phase of the solar activity. Finally, we discussed the possible increase of the dynamic pressure associated with the interplanetary shock causing the largest SC.

  16. Sudden unexplained death syndrome--a new manifestation in melioidosis?

    PubMed Central

    Yap, E. H.; Chan, Y. C.; Goh, K. T.; Chao, T. C.; Heng, B. H.; Thong, T. W.; Tan, H. C.; Thong, K. T.; Jacob, E.; Singh, M.

    1991-01-01

    The indirect haemagglutination (IHA) test using sensitized turkey erythrocytes and the indirect immunofluorescence assay (IgM-IFA) was confirmed to be sensitive in the detection of a recent or current Pseudomonas pseudomallei infection in 19 culture-confirmed Singapore melioidosis patients. All were found to have antibody titres from 4 to 32768 in the IHA test and 10 to 320 in the IgM-IFA test. When these tests were employed on sera from 16 immigrant Thai construction workers who died of sudden unexplained death syndrome (SUDS) and 73 healthy Thai fellow workers, 93.8% and 68.8% of SUDS cases had IHA titre of greater than or equal to 4 and IgM-IFA titre of greater than or equal to 10 respectively, in contrast to 39.7% and 12.3% found among healthy Thai workers. These data indicate that at the time of death, most of the SUDS patients had an active infection with P. pseudomallei, possibly resulting from reactivation of a latent infection. The aetiological role of P. pseudomallei as the major cause of SUDS is discussed. PMID:1721589

  17. Adjusting to a sudden “aging” of the lens

    PubMed Central

    Tregillus, Katherine E.M.; Werner, John S.; Webster, Michael A.

    2016-01-01

    Color perception is known to remain largely stable across the lifespan despite the pronounced changes in sensitivity from factors such as the progressive brunescence of the lens. However, the mechanisms and timescales controlling these compensatory adjustments are still poorly understood. In a series of experiments, we tracked adaptation in observers after introducing a sudden change in lens density by having observers wear glasses with yellow filters that approximated the average spectral transmittance of a 70-year-old lens. Individuals were young adults and wore the glasses for 5 days for 8 hours per day while engaged in their normal activities. Achromatic settings were measured on a CRT before and after each daily exposure with the lenses on and off, and were preceded by 5 minutes of dark adaptation to control for short-term chromatic adaptation. During each day, there was a large shift in the white settings consistent with a partial compensation for the added lens density. However, there was little to no evidence of an after-image at the end of each daily session, and participants’ perceptual nulls were roughly aligned with the nulls for short-term chromatic adaptation, suggesting a rapid renormalization when the lenses were removed. The long-term drift was also extinguished by brief exposure to a white adapting field. The results point to distinct timescales and potentially distinct mechanisms compensating for changes in the chromatic sensitivity of the observer. PMID:26924924

  18. Noninvasive imaging markers associated with sudden cardiac death.

    PubMed

    van der Bijl, Pieter; Delgado, Victoria; Bax, Jeroen J

    2016-05-01

    Sudden cardiac death (SCD) accounts for approximately 15-20% of all deaths worldwide. While the majority of SCDs occur in adults, children, and adults <35 years (<1%) may also be affected. Currently the most effective strategy for both primary and secondary prevention of SCD is the implantable cardioverter-defibrillator (ICD). However, identification of patients who will benefit from ICD implantation remains challenging. Left ventricular ejection fraction (LVEF) is the most frequent imaging parameter used to select patients for ICD implantation for primary prevention. However, LVEF has shown to be suboptimal for prediction of benefit. Non-invasive cardiac imaging permits characterization of the arrhythmogenic substrate, including dispersion of electromechanical activation, presence of myocardial scar, and cardiac innervation status. The arrhythmogenic substrate may change across the different underlying diseases. While in ischemic cardiomyopathy, differentiation and characterization of infarct core and peri-infarct zone have been shown to refine the risk stratification of patients, in non-ischemic cardiomyopathies, the substrate may be more heterogeneous and tissue characterization assessing focal and diffuse fibrosis and inflammation processes may be more relevant. Furthermore, in channelopathies, assessment of mechanical dispersion between myocardial layers may identify the patients with increased risk of ventricular arrhythmias. Finally, potential triggers of ventricular arrhythmias such as myocardial ischemia can be evaluated. The role of noninvasive imaging in the risk stratification of SCD and the selection of candidates for ICD will be discussed in this article. PMID:26632012

  19. Venezuelan Equine Encephalitis Virus Activity in the Gulf Coast Region of Mexico, 2003–2010

    PubMed Central

    Adams, A. Paige; Navarro-Lopez, Roberto; Ramirez-Aguilar, Francisco J.; Lopez-Gonzalez, Irene; Leal, Grace; Flores-Mayorga, Jose M.; Travassos da Rosa, Amelia P. A.; Saxton-Shaw, Kali D.; Singh, Amber J.; Borland, Erin M.; Powers, Ann M.; Tesh, Robert B.; Weaver, Scott C.; Estrada-Franco, Jose G.

    2012-01-01

    Venezuelan equine encephalitis virus (VEEV) has been the causative agent for sporadic epidemics and equine epizootics throughout the Americas since the 1930s. In 1969, an outbreak of Venezuelan equine encephalitis (VEE) spread rapidly from Guatemala and through the Gulf Coast region of Mexico, reaching Texas in 1971. Since this outbreak, there have been very few studies to determine the northward extent of endemic VEEV in this region. This study reports the findings of serologic surveillance in the Gulf Coast region of Mexico from 2003–2010. Phylogenetic analysis was also performed on viral isolates from this region to determine whether there have been substantial genetic changes in VEEV since the 1960s. Based on the findings of this study, the Gulf Coast lineage of subtype IE VEEV continues to actively circulate in this region of Mexico and appears to be responsible for infection of humans and animals throughout this region, including the northern State of Tamaulipas, which borders Texas. PMID:23133685

  20. MAG4 versus Alternative Techniques for Forecasting Active-Region Flare Productivity

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    MAG4 is a technique of forecasting an active region's rate of production of major flares in the coming few days from a free-magnetic-energy proxy. We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region’s major-flare productivity from alternative observed aspects of the active region. We demonstrate the method by measuring the difference in performance between the “Present MAG4” technique and each of three alternative techniques, called “McIntosh Active-Region Class,” “Total Magnetic Flux,” and “Next MAG4.” We do this by using (1) the MAG4 database of magnetograms and major-flare histories of sunspot active regions, (2) the NOAA table of the major-flare productivity of each of 60 McIntosh active-region classes of sunspot active regions, and (3) five technique-performance metrics (Heidke Skill Score, True Skill Score, Percent Correct, Probability of Detection, and False Alarm Rate) evaluated from 2000 random two-by-two contingency tables obtained from the databases. We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4). Funding for this research came from NASA’s Game Changing Development Program, Johnson Space Center’s Space Radiation Analysis Group (SRAG), and AFOSR’s Multi-University Research Initiative. In particular, funding was facilitated by Dr. Dan Fry (NASA-JSC) and David Moore (NASA-LaRC).

  1. Regional brain effects of sodium azide treatment on cytochrome oxidase activity: a quantitative histochemical study.

    PubMed

    Cada, A; Gonzalez-Lima, F; Rose, G M; Bennett, M C

    1995-12-01

    The objective of the present study was to determine if regional variation in brain cytochrome oxidase activity was observed following systemic administration of sodium azide. An image analysis system calibrated with internal standards of known cytochrome oxidase activity was used to quantify cytochrome oxidase in histochemically stained brain sections. Rats receiving chronic infusion of sodium azide (400 micrograms/hr), which were sacrificed after two weeks, showed a substantial decrease in brain cytochrome oxidase activity over those infused with saline. All of the 22 regions sampled from telencephalic, diencephalic, and mesencephalic levels, showed a significant activity reduction which ranged between 26% and 37%. The regions that appeared significantly more vulnerable to the sodium azide effects were the mesencephalic reticular formation and the central amygdala, which displayed the largest decrease in activity. In addition, interregional correlations of activity showed a deeply modified pattern of correlative metabolic activity between hippocampal, amygdaloid and cortical areas after azide treatment. The regional effects found were consistent with azide-induced learning and memory dysfunctions. PMID:8847994

  2. Determining heating timescales in solar active region cores from AIA/SDO Fe XVIII images

    SciTech Connect

    Ugarte-Urra, Ignacio; Warren, Harry P.

    2014-03-01

    We present a study of the frequency of transient brightenings in the core of solar active regions as observed in the Fe XVIII line component of AIA/SDO 94 Å filter images. The Fe XVIII emission is isolated using an empirical correction to remove the contribution of 'warm' emission to this channel. Comparing with simultaneous observations from EIS/Hinode, we find that the variability observed in Fe XVIII is strongly correlated with the emission from lines formed at similar temperatures. We examine the evolution of loops in the cores of active regions at various stages of evolution. Using a newly developed event detection algorithm, we characterize the distribution of event frequency, duration, and magnitude in these active regions. These distributions are similar for regions of similar age and show a consistent pattern as the regions age. This suggests that these characteristics are important constraints for models of solar active regions. We find that the typical frequency of the intensity fluctuations is about 1400 s for any given line of sight, i.e., about two to three events per hour. Using the EBTEL 0D hydrodynamic model, however, we show that this only sets a lower limit on the heating frequency along that line of sight.

  3. Repetitive transcranial magnetic stimulation improves both hearing function and tinnitus perception in sudden sensorineural hearing loss patients

    PubMed Central

    Zhang, Dai; Ma, Yuewen

    2015-01-01

    The occurrence of sudden sensorineural hearing loss (SSHL) affects not only cochlear activity but also neural activity in the central auditory system. Repetitive transcranial magnetic stimulation (rTMS) above the auditory cortex has been reported to improve auditory processing and to reduce the perception of tinnitus, which results from network dysfunction involving both auditory and non-auditory brain regions. SSHL patients who were refractory to standard corticosteroid therapy (SCT) and hyperbaric oxygen (HBO) therapy received 20 sessions of 1 Hz rTMS to the temporoparietal junction ipsilateral to the symptomatic ear (rTMS group). RTMS therapy administered in addition to SCT and HBO therapy resulted in significantly greater recovery of hearing function and improvement of tinnitus perception compared SCT and HBO therapy without rTMS therapy. Additionally, the single photon emission computed tomography (SPECT) measurements obtained in a subgroup of patients suggested that the rTMS therapy could have alleviated the decrease in regional cerebral brain flow (rCBF) in SSHL patients. RTMS appears to be an effective, practical, and safe treatment strategy for SSHL. PMID:26463446

  4. Repetitive transcranial magnetic stimulation improves both hearing function and tinnitus perception in sudden sensorineural hearing loss patients.

    PubMed

    Zhang, Dai; Ma, Yuewen

    2015-01-01

    The occurrence of sudden sensorineural hearing loss (SSHL) affects not only cochlear activity but also neural activity in the central auditory system. Repetitive transcranial magnetic stimulation (rTMS) above the auditory cortex has been reported to improve auditory processing and to reduce the perception of tinnitus, which results from network dysfunction involving both auditory and non-auditory brain regions. SSHL patients who were refractory to standard corticosteroid therapy (SCT) and hyperbaric oxygen (HBO) therapy received 20 sessions of 1 Hz rTMS to the temporoparietal junction ipsilateral to the symptomatic ear (rTMS group). RTMS therapy administered in addition to SCT and HBO therapy resulted in significantly greater recovery of hearing function and improvement of tinnitus perception compared SCT and HBO therapy without rTMS therapy. Additionally, the single photon emission computed tomography (SPECT) measurements obtained in a subgroup of patients suggested that the rTMS therapy could have alleviated the decrease in regional cerebral brain flow (rCBF) in SSHL patients. RTMS appears to be an effective, practical, and safe treatment strategy for SSHL. PMID:26463446

  5. Mitochondria Oxidative Stress, Connexin43 Remodeling, and Sudden Arrhythmic Death

    PubMed Central

    Sovari, Ali A.; Rutledge, Cody A.; Jeong, Euy-Myoung; Dolmatova, Elena; Arasu, Divya; Liu, Hong; Vahdani, Nooshin; Gu, Lianzhi; Zandieh, Shadi; Xiao, Lei; Bonini, Marcelo G.; Duffy, Heather S.; Dudley, Samuel C.

    2013-01-01

    Background Previously, we showed a mouse model (ACE8/8) of cardiac renin-angiotensin system (RAS) activation has a high rate of spontaneous ventricular tachycardia (VT) and sudden cardiac death (SCD) secondary to a reduction in connexin43 (Cx43) level. Angiotensin-II activation increases reactive oxygen species (ROS) production, and ACE8/8 mice show increased cardiac ROS. We sought to determine the source of ROS and if ROS played a role in the arrhythmogenesis. Methods and Results Wild-type and ACE8/8 mice with and without two weeks of treatment with L-NIO (nitric oxide synthase inhibitor), sepiapterin (precursor of tetrahydrobiopterin), MitoTEMPO (mitochondria-targeted antioxidant), TEMPOL (a general antioxidant), apocynin (NADPH oxidase inhibitor), allopurinol (xanthine oxidase inhibitor), and ACE8/8 crossed with P67 dominant negative mice to inhibit the NADPH oxidase were studied. Western blotting, detection of mitochondrial ROS by MitoSOX Red, electron microscopy, immunohistochemistry, fluorescent dye diffusion technique for functional assessment of Cx43, telemetry monitoring, and in-vivo electrophysiology studies were performed. Treatment with MitoTEMPO reduced SCD in ACE8/8 mice (from 74% to 18%, P<0.005), decreased spontaneous ventricular premature beats, decreased VT inducibility (from 90% to 17%, P<0.05), diminished elevated mitochondrial ROS to the control level, prevented structural damage to mitochondria, resulted in 2.6 fold increase in Cx43 level at the gap junctions, and corrected gap junction conduction. None of the other antioxidant therapies prevented VT and SCD in ACE8/8 mice. Conclusions Mitochondrial oxidative stress plays a central role in angiotensin II-induced gap junction remodeling and arrhythmia. Mitochondria-targeted antioxidants may be effective antiarrhythmic drugs in cases of RAS activation. PMID:23559673

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  7. Minifilament Eruptions that Drive Coronal Jets in a Solar Active Region

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  8. Analysis of Seismic Activity of the last 15 Years Nearby Puerto Rico and Caribbean Region.

    NASA Astrophysics Data System (ADS)

    Huerta-Lopez, C. I.; Torres-Ortíz, D. M.; Fernández-Heredia, A. I.; Martínez-Cruzado, J. A.

    2015-12-01

    An earthquake catalog of the seismicity occurred during the last 15 years in the Caribbean region, nearby the vicinity of Puerto Rico Island (PRI) was compiled in order to capture the big picture of the regional seismic activity ratio and in particular at the epicentral regions of several historical and instrumentally recorded (during 2008-20015) large to moderate magnitude earthquakes occurred nearby PRI in onshore and offshore, which include the M6.4 earthquake of 01/13/2014, the largest earthquake recorded instrumentally nearby PRI. From the point of view of joint temporal-spatial distribution of epicenters, episodic temporal-spatial seismic activity is clearly seen as temporal-spatial concentrations during certain time intervals in different regions. These localized concentrations of epicenters that occur during certain time intervals in well localized/concentrated regions may suggest "seismic gaps" that shows no regular time interval, neither spatial pattern. In the epicentral region of the M6.4 01/13/2014 earthquake and the historical Mona Passage M7.5 earthquake of 10/11/1918, episodic concentrations in time and space of small magnitude earthquakes epicenters is evident, however do not show temporal pattern. Preliminary results of statistical analysis of an ongoing research in terms of the parameter b (Gutenberg-Richter relationship), and the Omori's law with the aim to relate the tectonic framework of the region (or sub-regions) such as structural heterogeneity stress are here presented/discussed.

  9. The study of a spatial relationship between the Equatorial coronal hole and the Active region

    NASA Astrophysics Data System (ADS)

    Karna, Mahendra; Karna, Nishu

    2016-05-01

    The 11-year solar cycle is characterized by the periodic change in the solar activity like sunspot numbers, coronal holes, active regions, eruptions such as flares and coronal mass ejections. We study the relationship between equatorial coronal holes (ECH) and the active regions (AR) as coronal hole positions and sizes change with the solar cycle. We made a detailed study for two solar maximum: Solar Cycle 23 (1999, 2000, 2001 and 2002) and Solar Cycle 24 (2011, 2012 and 2013). We used publically available Heliophysics Feature Catalogue and NOAA Solar Geophysical data for. Moreover, we used daily Solar Region Summary (SRS) data from SWPC/NOAA website. We examined the position of ECH and AR and noted that during a maximum of 23, the majority of ECH were not near active regions. However, in cycle 24 coronal holes and equatorial holes were more close to each other. Moreover, we noticed the asymmetry in AR migrations towards the lower latitude in both Northern and Southern hemisphere in cycle 23. While, no such notable asymmetrical behavior was observed in a maximum of cycle 24. Our goal is to extend the study with cycle 21 and 22 and examine the correlation between equatorial holes, the active regions, and the flares. This combined study will shed light in determining the distribution of flares.

  10. Evidence for Widespread Cooling in an Active Region Observed with the SDO Atmospheric Imaging Assembly

    NASA Technical Reports Server (NTRS)

    Viall, Nicholeen M.; Klimchuk, James A.

    2012-01-01

    A well known behavior of EUV light curves of discrete coronal loops is that the peak intensities of cooler channels or spectral lines are reached at progressively later times. This time lag is understood to be the result of hot coronal loop plasma cooling through these lower respective temperatures. However, loops typically comprise only a minority of the total emission in active regions. Is this cooling pattern a common property of active region coronal plasma, or does it only occur in unique circumstances, locations, and times? The new SDO/AIA data provide a wonderful opportunity to answer this question systematically for an entire active region. We measure the time lag between pairs of SDO/AIA EUV channels using 24 hours of images of AR 11082 observed on 19 June 2010. We find that there is a time-lag signal consistent with cooling plasma, just as is usually found for loops, throughout the active region including the diffuse emission between loops for the entire 24 hour duration. The pattern persists consistently for all channel pairs and choice of window length within the 24 hour time period, giving us confidence that the plasma is cooling from temperatures of greater than 3 MK, and sometimes exceeding 7 MK, down to temperatures lower than approx. 0.8 MK. This suggests that the bulk of the emitting coronal plasma in this active region is not steady; rather, it is dynamic and constantly evolving. These measurements provide crucial constraints on any model which seeks to describe coronal heating.

  11. Different Modes of Turbulence in the Active Regions of the Solar Photosphere

    NASA Astrophysics Data System (ADS)

    Kozak, L. V.; Kostik, R. I.; Cheremnykh, O. K.

    In work the range of different methods for the analysis of characteristics of turbulent processes in the active regions of the solar photosphere has been used. The changes of fluctuations distribution function and its moments were analyzed, spectral analysis was carried out.It was found out from the observations of active region carried out with the 70-cm vacuum tower telescope VTT in Isanie (Tenerife Island, Spain) that the turbulent processes in the sun photosphere are characterized by two different spectra of turbulence. The first one of them is well known Kolmohorov spectrum, which describes the plasma with zero mean magnetic field. The second one is the Kraichnan spectrum with a different from zero mean magnetic field. Transition from one spectrum type to another one occurs at scale of 3 Mm.We have to note that the scale 3 Mm corresponds to one of mesogranulation and testifies about non-zero mean magnetic fields for the consideration of regions exceeding the granulation in active regions of the photosphere. Besides, this clears the possibility of appearance of selforganizing magnetic plasma structures such as spots, active regions and complexes of activity.

  12. Spontaneous regional brain activity links restrained eating to later weight gain among young women.

    PubMed

    Dong, Debo; Jackson, Todd; Wang, Yulin; Chen, Hong

    2015-07-01

    Theory and prospective studies have linked restrained eating (RE) to risk for future weight gain and the onset of obesity, but little is known about resting state neural activity that may underlie this association. To address this gap, resting fMRI was used to test the extent to which spontaneous neural activity in regions associated with inhibitory control and food reward account for potential relations between baseline RE levels and changes in body weight among dieters over a one-year interval. Spontaneous regional activity patterns corresponding to RE were assessed among 50 young women using regional homogeneity (ReHo) analysis, which measured temporal synchronization of spontaneous fluctuations within a food deprivation condition. Analyses indicated higher baseline RE scores predicted more weight gain at a one-year follow-up. Furthermore, food-deprived dieting women with high dietary restraint scores exhibited more spontaneous local activity in brain regions associated with the expectation and valuation for food reward [i.e., orbitofrontal cortex (OFC)/ventromedial prefrontal cortex (VMPFC)] and reduced spontaneous local activity in inhibitory control regions [i.e., bilateral dorsal-lateral prefrontal cortex (DLPFC)] at baseline. Notably, the association between baseline RE and follow-up weight gain was mediated by decreased local synchronization of the right DLPFC in particular and, to a lesser degree, increased local synchronization of the right VMPFC. In conjunction with previous research, these findings highlight possible neural mechanisms underlying the relation between RE and risk for weight gain. PMID:26004091

  13. Sudden Gains in Prolonged Exposure and Sertraline for Chronic PTSD

    PubMed Central

    Jun, Janie J.; Zoellner, Lori A.; Feeny, Norah C.

    2014-01-01

    Background Sudden gains are significant, rapid improvements in symptoms, larger than typical between-session symptom reduction.[8] Sudden gains in a large sample of individuals with PTSD have not been studied, and only one study has looked at it in pharmacotherapy, but not in PTSD. In the present study, we examined the occurrence of sudden gains in psychotherapy, specifically prolonged exposure (PE), and pharmacotherapy, specifically sertraline, for chronic PTSD. Method Sudden gains in PTSD symptoms (PTSD Symptom Scale-Self-Report[23]) were assessed in 200 individuals with PTSD during 10 weeks of PE or sertraline. Results Individuals in both PE (42.2%) and sertraline (31%) exhibited sudden gains. Individuals in PE made more gains toward the end of treatment (7.2%) than sertraline (2%, OR = 3.82). However, individuals in sertraline made larger gains during early treatment (M = 18.35, SD = 8.15) than PE (M = 12.53, SD = 5.16, d = .85). Notably, those on sertraline were more likely to exhibit a reversal of sudden gains than those in PE (OR = .23). Pointing to clinical significance, the presence of a sudden gain was associated with better reduction in symptoms from pre- to post-treatment (β = -.49). Conclusions Individuals in both PE and sertraline experienced gains, though sertraline was associated with earlier large but reversible gains, and PE was associated with later gains. This differential pattern of discontinuous change highlights potential differential mechanism for these therapies and marks important transition points for further detailed analyses of change mechanisms. PMID:23633445

  14. Seasonal forecasting of lightning and thunderstorm activity in tropical and temperate regions of the world

    PubMed Central

    Dowdy, Andrew J.

    2016-01-01

    Thunderstorms are convective systems characterised by the occurrence of lightning. Lightning and thunderstorm activity has been increasingly studied in recent years in relation to the El Niño/Southern Oscillation (ENSO) and various other large-scale modes of atmospheric and oceanic variability. Large-scale modes of variability can sometimes be predictable several months in advance, suggesting potential for seasonal forecasting of lightning and thunderstorm activity in various regions throughout the world. To investigate this possibility, seasonal lightning activity in the world’s tropical and temperate regions is examined here in relation to numerous different large-scale modes of variability. Of the seven modes of variability examined, ENSO has the strongest relationship with lightning activity during each individual season, with relatively little relationship for the other modes of variability. A measure of ENSO variability (the NINO3.4 index) is significantly correlated to local lightning activity at 53% of locations for one or more seasons throughout the year. Variations in atmospheric parameters commonly associated with thunderstorm activity are found to provide a plausible physical explanation for the variations in lightning activity associated with ENSO. It is demonstrated that there is potential for accurately predicting lightning and thunderstorm activity several months in advance in various regions throughout the world. PMID:26865431

  15. Seasonal forecasting of lightning and thunderstorm activity in tropical and temperate regions of the world

    NASA Astrophysics Data System (ADS)

    Dowdy, Andrew J.

    2016-02-01

    Thunderstorms are convective systems characterised by the occurrence of lightning. Lightning and thunderstorm activity has been increasingly studied in recent years in relation to the El Niño/Southern Oscillation (ENSO) and various other large-scale modes of atmospheric and oceanic variability. Large-scale modes of variability can sometimes be predictable several months in advance, suggesting potential for seasonal forecasting of lightning and thunderstorm activity in various regions throughout the world. To investigate this possibility, seasonal lightning activity in the world’s tropical and temperate regions is examined here in relation to numerous different large-scale modes of variability. Of the seven modes of variability examined, ENSO has the strongest relationship with lightning activity during each individual season, with relatively little relationship for the other modes of variability. A measure of ENSO variability (the NINO3.4 index) is significantly correlated to local lightning activity at 53% of locations for one or more seasons throughout the year. Variations in atmospheric parameters commonly associated with thunderstorm activity are found to provide a plausible physical explanation for the variations in lightning activity associated with ENSO. It is demonstrated that there is potential for accurately predicting lightning and thunderstorm activity several months in advance in various regions throughout the world.

  16. Divalent cations activate TRPV1 through promoting conformational change of the extracellular region

    PubMed Central

    Yang, Fan; Ma, Linlin; Cao, Xu

    2014-01-01

    Divalent cations Mg2+ and Ba2+ selectively and directly potentiate transient receptor potential vanilloid type 1 heat activation by lowering the activation threshold into the room temperature range. We found that Mg2+ potentiates channel activation only from the extracellular side; on the intracellular side, Mg2+ inhibits channel current. By dividing the extracellularly accessible region of the channel protein into small segments and perturbing the structure of each segment with sequence replacement mutations, we observed that the S1–S2 linker, the S3–S4 linker, and the pore turret are all required for Mg2+ potentiation. Sequence replacements at these regions substantially reduced or eliminated Mg2+-induced activation at room temperature while sparing capsaicin activation. Heat activation was affected by many, but not all, of these structural alternations. These observations indicate that extracellular linkers and the turret may interact with each other. Site-directed fluorescence resonance energy transfer measurements further revealed that, like heat, Mg2+ also induces structural changes in the pore turret. Interestingly, turret movement induced by Mg2+ precedes channel activation, suggesting that Mg2+-induced conformational change in the extracellular region most likely serves as the cause of channel activation instead of a coincidental or accommodating structural adjustment. PMID:24344245

  17. Seasonal forecasting of lightning and thunderstorm activity in tropical and temperate regions of the world.

    PubMed

    Dowdy, Andrew J

    2016-01-01

    Thunderstorms are convective systems characterised by the occurrence of lightning. Lightning and thunderstorm activity has been increasingly studied in recent years in relation to the El Niño/Southern Oscillation (ENSO) and various other large-scale modes of atmospheric and oceanic variability. Large-scale modes of variability can sometimes be predictable several months in advance, suggesting potential for seasonal forecasting of lightning and thunderstorm activity in various regions throughout the world. To investigate this possibility, seasonal lightning activity in the world's tropical and temperate regions is examined here in relation to numerous different large-scale modes of variability. Of the seven modes of variability examined, ENSO has the strongest relationship with lightning activity during each individual season, with relatively little relationship for the other modes of variability. A measure of ENSO variability (the NINO3.4 index) is significantly correlated to local lightning activity at 53% of locations for one or more seasons throughout the year. Variations in atmospheric parameters commonly associated with thunderstorm activity are found to provide a plausible physical explanation for the variations in lightning activity associated with ENSO. It is demonstrated that there is potential for accurately predicting lightning and thunderstorm activity several months in advance in various regions throughout the world. PMID:26865431

  18. Plasma outflows at the border of active regions and the solar wind

    NASA Astrophysics Data System (ADS)

    Nuevo, F. A.; Mandrini, C. H.; Vásquez, A. M.; Deumoulin, P.; Van Driel-Gesztely, L.; Baker, D.; Cristiani, G. D.; Pick, M.; Culhane, J. L.

    We present a detailed topological analysis of active region (AR) 10978; based on a Potential Field Source Surface (PFSS) model. AR 10978 is a standard bipolar region which appears fully covered by the magnetic field lines of a coronal streamer. Despite this simple magnetic configuration; our analysis shows that it is possible for the AR plasma; contained in the outflows observed at the AR borders; to be released into the solar wind via magnetic reconnection.

  19. A statistical study of the subsurface structure and eruptivity of solar active regions

    NASA Astrophysics Data System (ADS)

    Lin, C.-H.

    2014-08-01

    A statistical study of 77 solar active regions (ARs) is conducted to investigate the existence of identifiable correlations between the subsurface structural disturbances and the activity level of the active regions. The disturbances examined in this study are <| δΓ 1/ Γ 1|>, <| δc 2/ c 2|>, and <| δc 2/ c 2- δΓ 1/ Γ 1|>, where Γ 1 and c are the thermodynamic properties of first adiabatic index and sound speed modified by magnetic field, respectively. The averages are over three depth layers: 0.975-0.98 R ⊙, 0.98-0.99 R ⊙ and 0.99-0.995 R ⊙ to represent the structural disturbances in that layer. The level of the surface magnetic activity is measured by the Magnetic Activity Index (MAI) of active region and the relative and absolute MAI differences (rdMAI and dMAI) between the active and quiet regions. The eruptivity of each active region is quantified by its Flare Index, total number of coronal mass ejections (CMEs), and total kinetic energy of the CMEs. The existence and level of the correlations are evaluated by scatter plots and correlation coefficients. No definitive correlation can be claimed from the results. While a weak positive trend is visible between dMAI and <| δΓ 1/ Γ 1|> and <| δc 2/ c 2|> in the layer 0.975-0.98 R ⊙, their correlation levels, being approximately 0.6, are not sufficiently high to justify the correlation. Some subsurface disturbances are seen to increase with eruptivity indices among ARs with high eruptivity. The statistical significance of such trend, however, cannot be ascertained due to the small number of very eruptive ARs in our sample.

  20. Detailed correlation of type III radio bursts with H alpha activity. I - Active region of 22 May 1970.

    NASA Technical Reports Server (NTRS)

    Kuiper, T. B. H.; Pasachoff, J. M.

    1973-01-01

    Comparison of observations of type III impulsive radio bursts made at the Clark Lake Radio Observatory with high-spatial-resolution cinematographic observations taken at the Big Bear Solar Observatory. Use of the log-periodic radio interferometer makes it possible to localize the radio emission uniquely. This study concentrates on the particularly active region close to the limb on May 22, 1970. Sixteen of the 17 groups were associated with some H alpha activity, 11 of them with the start of such activity.

  1. Oscillating flow and heat transfer in a channel with sudden cross section change

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir; Hashim, Waqar

    1993-01-01

    We have computationally examined oscillating flow (zero mean) between two parallel plates with a sudden change in cross section. The flow was assumed to be laminar incompressible with the inflow velocity uniform over the channel cross section but varying sinusoidally with time. The cases studied cover wide ranges of Re(sub max) (from 187.5 to 2000), Va (from 1 to 10.66), the expansion ratio (1:2 and 1:4) and A(sub r) (2 and 4). Also, three different geometric cases were discussed: (1) asymmetric expansion/contraction; (2) symmetric expansion/contraction; and (3) symmetric blunt body. For these oscillating flow conditions, the fluid undergoes sudden expansion in one-half of the cycle and sudden contraction inthe other half. The instantaneous friction factor, for some ranges of Re(sub max) and Va, deviated substantially from the steady-state friction factor for the same flow parameters. A region has been identified below which the flow is laminar quasi-steady. A videotape showing computer simulations of the oscillating flow demonstrates the usefulness of the current analyses in providing information on the transient hydraulic phenomena.

  2. Using Magnetic Helicity Diagnostics to Determine the Nature of Solar Active-Region Formation

    NASA Astrophysics Data System (ADS)

    Georgoulis, Manolis K.

    Employing a novel nonlinear force-free (NLFF) method that self-consistently infers instantaneous free magnetic-energy and relative magnetic-helicity budgets from single photospheric vector magnetograms, we recently constructed the magnetic energy-helicity (EH) diagram of solar active regions. The EH diagram implies dominant relative helicities of left-handed or right-handed chiralities for the great majority of active regions. The amplitude (budget) of these helicities scales monotonically with the free magnetic energy. This constructive, strongly preferential accumulation of a certain sense of magnetic helicity seems to disqualify recently proposed mechanisms relying on a largely random near-surface convection for the formation of the great majority of active regions. The existing qualitative formation mechanism for these regions remains the conventional Omega-loop emergence following a buoyant ascension from the bottom of the convection zone. However, exceptions to this rule include even eruptive active regions: NOAA AR 11283 is an obvious outlier to the EH diagram, involving significant free magnetic energy with a small relative magnetic helicity. Relying on a timeseries of vector magnetograms of this region, our methodology shows nearly canceling amounts of both senses of helicity and an overall course from a weakly left-handed to a weakly right-handed structure, in the course of which a major eruption occurs. For this and similarly behaving active regions the latest near-surface formation scenario might conceivably be employed successfully. Research partially supported by the EU Seventh Framework Programme under grant agreement No. PIRG07-GA-2010-268245 and by the European Union Social Fund (ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: Thales. Investing in knowledge society through the European Social Fund.

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

    NASA Astrophysics Data System (ADS)

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

    2006-08-01

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

  4. Calculating Non-Potentiality in Solar Active Regions Using SDO/HMI Vector Magnetic Field Data

    NASA Astrophysics Data System (ADS)

    Bobra, M.; Hoeksema, J. T.

    2010-12-01

    Non-potential magnetic fields in solar active regions are thought to be associated with flare occurrence. In this study, we parametrize the non-potentiality of several active regions, using data from the Helioseismic and Magnetic Imager (HMI) aboard the Solar Dynamics Observatory (SDO), and correlate these parameters with flare occurrence. In particular, we focus on a parameter that we call the Gradient-Weighted Inversion Line Length (GWILL). Using data from SOHO/MDI, Mason et al. found that GWILL generally tends to increase before a solar flare. We investigate whether extending the analysis of Mason et. al. to a three-dimensional field enables us to derive better near real-time indicators of flare occurrence. Before HMI, the availability of vector magnetograms was sparse at best. HMI provides continuous vector magnetogram data at a 12-minute cadence. As such, this study represents the first parametrization of non-potentiality in solar active regions using continuous vector magnetic field data.

  5. Light Bridge in a Developing Active Region. I. Observation of Light Bridge and its Dynamic Activity Phenomena

    NASA Astrophysics Data System (ADS)

    Toriumi, Shin; Katsukawa, Yukio; Cheung, Mark C. M.

    2015-10-01

    Light bridges, the bright structures that divide the umbra of sunspots and pores into smaller pieces, are known to produce a wide variety of activity events in solar active regions (ARs). It is also known that the light bridges appear in the assembling process of nascent sunspots. The ultimate goal of this series of papers is to reveal the nature of light bridges in developing ARs and the occurrence of activity events associated with the light bridge structures from both observational and numerical approaches. In this first paper, exploiting the observational data obtained by Hinode, the Interface Region Imaging Spectrograph, and the Solar Dynamics Observatory, we investigate the detailed structure of the light bridge in NOAA AR 11974 and its dynamic activity phenomena. As a result, we find that the light bridge has a weak, horizontal magnetic field, which is transported from the interior by a large-scale convective upflow and is surrounded by strong, vertical fields of adjacent pores. In the chromosphere above the bridge, a transient brightening occurs repeatedly and intermittently, followed by a recurrent dark surge ejection into higher altitudes. Our analysis indicates that the brightening is the plasma heating due to magnetic reconnection at lower altitudes, while the dark surge is the cool, dense plasma ejected from the reconnection region. From the observational results, we conclude that the dynamic activity observed in a light bridge structure such as chromospheric brightenings and dark surge ejections are driven by magnetoconvective evolution within the light bridge and its interaction with the surrounding magnetic fields.

  6. Signatures of Slow Solar Wind Streams from Active Regions in the Inner Corona

    NASA Astrophysics Data System (ADS)

    Slemzin, V.; Harra, L.; Urnov, A.; Kuzin, S.; Goryaev, F.; Berghmans, D.

    2013-08-01

    The identification of solar-wind sources is an important question in solar physics. The existing solar-wind models ( e.g., the Wang-Sheeley-Arge model) provide the approximate locations of the solar wind sources based on magnetic field extrapolations. It has been suggested recently that plasma outflows observed at the edges of active regions may be a source of the slow solar wind. To explore this we analyze an isolated active region (AR) adjacent to small coronal hole (CH) in July/August 2009. On 1 August, Hinode/EUV Imaging Spectrometer observations showed two compact outflow regions in the corona. Coronal rays were observed above the active-region coronal hole (ARCH) region on the eastern limb on 31 July by STEREO-A/EUVI and at the western limb on 7 August by CORONAS- Photon/TESIS telescopes. In both cases the coronal rays were co-aligned with open magnetic-field lines given by the potential field source surface model, which expanded into the streamer. The solar-wind parameters measured by STEREO-B, ACE, Wind, and STEREO-A confirmed the identification of the ARCH as a source region of the slow solar wind. The results of the study support the suggestion that coronal rays can represent signatures of outflows from ARs propagating in the inner corona along open field lines into the heliosphere.

  7. Warrego Valles and Other Candidate Sites of Local Hydrothermal Activity Within The Thaumasia Region, Mars

    NASA Technical Reports Server (NTRS)

    Dohm, J. M.; Tanaka, K. L.; Lias, J. H.; Hare, T. M.; Anderson, R. C.; Gulick, V. C.

    1998-01-01

    We have previously demonstrated for the Thaumasia region of Mars that: (1) valley formation peaked during the Noachian and declined substantially during the Hesperian and Amazonian Periods and (2) valleys, many of which form networking systems, largely occur near volcanoes, highly faulted terrains, and large impact craters of similar age, thus suggesting hydrothermal activity. In Tanaka et al, the various hypotheses for valley formation on Mars are presented, and a geologic explanation for valley erosion in the Thaumasia region is given that "best fits" the region's geographic and geologic datasets. That comprehensive GIS-based investigation suggests that hydrothermal and seismic activity were the primary causes of valley formation in the Thaumasia region; the data make widespread precipitation less likely as a major factor in valley formation, except perhaps during the Early Noachian, for which much of the geologic record has been destroyed. Based on the reconstruction of the stratigraphic, tectonic, volcanic, and erosional histories and the close association of valleys in time and space with Noachian to Early Hesperian volcanoes and rift systems and Hesperian to Early Amazonian impact craters less than 50 km in diameter, we propose 13 sites of hydrothermal activity within the Thaumasia region; these are the best examples of valleys associated with these geologic features, but there are other less pronounced correlations elsewhere in the region.

  8. Associations of season and region on objectively assessed physical activity and sedentary behaviour.

    PubMed

    Hagströmer, Maria; Rizzo, Nico S; Sjöström, Michael

    2014-01-01

    Seasonal and regional variation may influence physical activity (PA) patterns. These associations are in need of further investigation. The objective of the current study was to examine the association of season and region on objectively measured PA. The study was designed as a cross-sectional study with 1172 participants living in Sweden. Data on PA were collected throughout a calendar year using accelerometry. Regions were categorised as south (Götaland), central (Svealand) and north (Norrland). Outcome variables included accelerometer-measured mean counts per minute, sedentary time and time in low intensity and moderate-intensity physical activity (MVPA) or greater. ANCOVA was used to determine the associations of season and region with PA, adjusting for sex, age, body mass index (BMI) and education. The results showed that during the Spring season more time was spent in MVPA than during the Autumn. For participants living in the south of Sweden, a significant trend for season was found for MVPA, with Spring having the highest MVPA (P = 0.025). Season had a borderline significant association with MVPA or higher intensity activities (P = 0.051). No significant effects of region or season on total PA, low-intensity PA and sedentary periods of time were observed. The results indicate that studies conducted in a population living in high latitudes, may not be significantly affected by seasonality or region when assessing PA. PMID:24102558

  9. Strategies for the prevention of sudden cardiac death during sports.

    PubMed

    Corrado, Domenico; Drezner, Jonathan; Basso, Cristina; Pelliccia, Antonio; Thiene, Gaetano

    2011-04-01

    Sudden cardiac death of a young athlete is the most tragic event in sports and devastates the family, the sports medicine team, and the local community. Such a fatality represents the first manifestation of cardiac disease in up to 80% of young athletes who remain asymptomatic before sudden cardiac arrest occurs; this explains the limited power of screening modalities based solely on history and physical examination. The long-running Italian experience showed that electrocardiogram (ECG) screening definitively improves the sensitivity of pre-participation evaluation for heart diseases and substantially reduces the risk of death in the athletic field (primary prevention). However, some cardiac conditions, such as coronary artery diseases, present no abnormalities on 12-lead ECG. Moreover, cardiac arrest due to non-penetrating chest injury (commotio cordis) cannot be prevented by screening. This justifies the efforts for implementing programmes of early external defibrillation of unpredictable arrhythmic cardiac arrest. This article reviews the epidemiology of sudden cardiac arrest in the athlete in terms of incidence, sport-related risk, underlying causes, and the currently available prevention programmes such as pre-participation screening and early external defibrillation by using automated external defibrillators. The best strategy is to combine synergistically primary prevention of sudden cardiac death by pre-participation identification of athletes affected by at-risk cardiomyopathies and secondary prevention with back-up defibrillation of unpredictable sudden cardiac arrest on the athletic field. PMID:21567995

  10. ON THE STRENGTH OF THE HEMISPHERIC RULE AND THE ORIGIN OF ACTIVE-REGION HELICITY

    SciTech Connect

    Wang, Y.-M.

    2013-10-01

    Vector magnetograph and morphological observations have shown that the solar magnetic field tends to have negative (positive) helicity in the northern (southern) hemisphere, although only ∼60%-70% of active regions appear to obey this 'hemispheric rule'. In contrast, at least ∼80% of quiescent filaments and filament channels that form during the decay of active regions follow the rule. We attribute this discrepancy to the difficulty in determining the helicity sign of newly emerged active regions, which are dominated by their current-free component; as the transverse field is canceled at the polarity inversion lines, however, the axial component becomes dominant there, allowing a more reliable determination of the original active-region chirality. We thus deduce that the hemispheric rule is far stronger than generally assumed, and cannot be explained by stochastic processes. Earlier studies have shown that the twist associated with the axial tilt of active regions is too small to account for the observed helicity; here, both tilt and twist are induced by the Coriolis force acting on the diverging flow in the emerging flux tube. However, in addition to this east-west expansion about the apex of the loop, each of its legs must expand continually in cross section during its rise through the convection zone, thereby acquiring a further twist through the Coriolis force. Since this transverse pressure effect is not limited by drag or tension forces, the final twist depends mainly on the rise time, and may be large enough to explain the observed active-region helicity.

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  12. Videomagnetograph studies of solar magnetic fields. II - Field changes in an active region

    NASA Technical Reports Server (NTRS)

    Schoolman, S. A.

    1973-01-01

    Using the Caltech videomagnetograph, we obtained a 6.5-hr movie of the magnetic fields in a young active region. The major contribution to the short term magnetic evolution of the region was provided by many discrete magnetic points which move in apparently random directions with typical velocities of 0.4 - 1.0 km/sec. The majority of these features appear to be footpoints of new EFR's, which emerge at an observed rate of one to two per hour. The pattern of the motions suggests that the magnetic evolution of a growing region cannot be principally due to photospheric convective cells.

  13. Doppler shift of hot coronal lines in a moss area of an active region

    NASA Astrophysics Data System (ADS)

    Dadashi, N.; Teriaca, L.; Tripathi, D.; Solanki, S. K.; Wiegelmann, T.

    2012-12-01

    The moss is the area at the footpoint of the hot (3 to 5 MK) loops forming the core of the active region where emission is believed to result from the heat flux conducted down to the transition region from the hot loops. Studying the variation of Doppler shift as a function of line formation temperatures over the moss area can give clues on the heating mechanism in the hot loops in the core of the active regions. We investigate the absolute Doppler shift of lines formed at temperatures between 1 MK and 2 MK in a moss area within active region NOAA 11243 using a novel technique that allows determining the absolute Doppler shift of EUV lines by combining observations from the SUMER and EIS spectrometers. The inner (brighter and denser) part of the moss area shows roughly constant blue shift (upward motions) of 5 km s-1 in the temperature range of 1 MK to 1.6 MK. For hotter lines the blue shift decreases and reaches 1 km s-1 for Fe xv 284 Å (~2 MK). The measurements are discussed in relation to models of the heating of hot loops. The results for the hot coronal lines seem to support the quasi-steady heating models for nonsymmetric hot loops in the core of active regions.

  14. Effects of Simulated Heat Waves with Strong Sudden Cooling Weather on ApoE Knockout Mice.

    PubMed

    Zhang, Shuyu; Kuang, Zhengzhong; Zhang, Xiakun

    2015-06-01

    This study analyzes the mechanism of influence of heat waves with strong sudden cooling on cardiovascular diseases (CVD) in ApoE-/- mice. The process of heat waves with strong sudden cooling was simulated with a TEM1880 meteorological-environment simulation chamber according to the data obtained at 5 a.m. of 19 June 2006 to 11 p.m. of 22 June 2006. Forty-eight ApoE-/- mice were divided into six blocks based on their weight. Two mice from each block were randomly assigned to control, heat wave, temperature drop, and rewarming temperature groups. The experimental groups were transferred into the climate simulator chamber for exposure to the simulated heat wave process with strong sudden temperature drop. After 55, 59, and 75 h of exposure, the experimental groups were successively removed from the chamber to monitor physiological indicators. Blood samples were collected by decollation, and the hearts were harvested in all groups. The levels of heat stress factors (HSP60, SOD, TNF, sICAM-1, HIF-1α), cold stress factors (NE, EPI), vasoconstrictor factors (ANGII, ET-1, NO), and four items of blood lipid (TC, TG, HDL-C, and LDL-C) were measured in each ApoE-/- mouse. Results showed that the heat waves increased the levels of heat stress factors except SOD decreased, and decreased the levels of vasoconstrictor factors and blood lipid factors except TC increased. The strong sudden temperature drop in the heat wave process increased the levels of cold stress factors, vasoconstrictor factors and four blood lipid items (except the level of HDL-C which decreased) and decreased the levels of heat stress factors (except the level of SOD which increased). The analysis showed that heat waves could enhance atherosclerosis of ApoE-/- mice. The strong sudden temperature drop during the heat wave process increased the plasma concentrations of NE and ANGII, which indicates SNS activation, and resulted in increased blood pressure. NE and ANGII are vasoconstrictors involved in systemic

  15. Space charge effects on the active region of a planar organic photodetector

    NASA Astrophysics Data System (ADS)

    Agostinelli, T.; Caironi, M.; Natali, D.; Sampietro, M.; Biagioni, P.; Finazzi, M.; Duò, L.

    2007-06-01

    Planar organic photodetectors represent a simple, cheap, and versatile alternative to devices built in sandwich configuration. The nonuniform electric field distribution in these structures has significant consequences on the extent of the device active region, because photogeneration of free carriers in organic semiconductors is a field-assisted phenomenon. By means of microscopy mapping of the photocurrent in a poly(p-phenylene vinylene) based planar device, we show that due to the deep trapping of photogenerated electrons leading to negative space charge accumulation, exciton dissociation occurs only close to the positively biased electrode. The effect of large leakage currents in defining the device active region is also analyzed and discussed.

  16. RESEARCH PAPER: A logistic model for magnetic energy storage in solar active regions

    NASA Astrophysics Data System (ADS)

    Wang, Hua-Ning; Cui, Yan-Mei; He, Han

    2009-06-01

    Previous statistical analyses of a large number of SOHO/MDI full disk longitudinal magnetograms provided a result that demonstrated how responses of solar flares to photospheric magnetic properties can be fitted with sigmoid functions. A logistic model reveals that these fitted sigmoid functions might be related to the free energy storage process in solar active regions. Although this suggested model is rather simple, the free energy level of active regions can be estimated and the probability of a solar flare with importance over a threshold can be forecast within a given time window.

  17. Activities of the US Geological Survey in Applications of Remote Sensing in the Chesapeake Bay Region

    NASA Technical Reports Server (NTRS)

    Wray, J. R.

    1978-01-01

    The application of remote sensing in the Chesapeake Bay region has been a central concern of three project activities of the U.S. Geological Survey: two are developmental, and one is operational. The two developmental activities were experiments in land-use and land-cover inventory and change detection using remotely sensed data from aircraft and from the LANDSAT and Skylab satellites. One of these is CARETS (Central Atlantic Regional Ecological Test Site). The other developmental task is the Census Cities Experiment in Urban Change Detection. The present major concern is an operational land-use and land-cover data-analysis program, including a supporting geographical information system.

  18. Real-Time CME Forecasting Using HMI Active-Region Magnetograms and Flare History

    NASA Technical Reports Server (NTRS)

    Falconer, David; Moore, Ron; Barghouty, Abdulnasser F.; Khazanov, Igor

    2011-01-01

    We have recently developed a method of predicting an active region s probability of producing a CME, an X-class Flare, an M-class Flare, or a Solar Energetic Particle Event from a free-energy proxy measured from SOHO/MDI line-of-sight magnetograms. This year we have added three major improvements to our forecast tool: 1) Transition from MDI magnetogram to SDO/HMI magnetogram allowing us near-real-time forecasts, 2) Automation of acquisition and measurement of HMI magnetograms giving us near-real-time forecasts (no older than 2 hours), and 3) Determination of how to improve forecast by using the active region s previous flare history in combination with its free-energy proxy. HMI was turned on in May 2010 and MDI was turned off in April 2011. Using the overlap period, we have calibrated HMI to yield what MDI would measure. This is important since the value of the free-energy proxy used for our forecast is resolution dependent, and the forecasts are made from results of a 1996-2004 database of MDI observations. With near-real-time magnetograms from HMI, near-real-time forecasts are now possible. We have augmented the code so that it continually acquires and measures new magnetograms as they become available online, and updates the whole-sun forecast from the coming day. The next planned improvement is to use an active region s previous flare history, in conjunction with its free-energy proxy, to forecast the active region s event rate. It has long been known that active regions that have produced flares in the past are likely to produce flares in the future, and that active regions that are nonpotential (have large free-energy) are more likely to produce flares in the future. This year we have determined that persistence of flaring is not just a reflection of an active region s free energy. In other words, after controlling for free energy, we have found that active regions that have flared recently are more likely to flare in the future.

  19. Inter-Calibration of EIS, XRT and AIA using Active Region and Bright Point Data

    NASA Technical Reports Server (NTRS)

    Mulu-Moore, Fana M.; Winebarger, Amy R.; Winebarger, Amy R.; Farid, Samaiyah I.

    2012-01-01

    Certain limitations in our solar instruments have created the need to use several instruments together for long term and/or large field of view studies. We will, therefore, present an intercalibration study of the EIS, XRT and AIA instruments using active region and bright point data. We will use the DEMs calculated from EIS bright point observations to determine the expected AIA and XRT intensities. We will them compare to the observed intensities and calculate a correction factor. We will consider data taken over a year to see if there is a time dependence to the correction factor. We will then determine if the correction factors are valid for active region observations.

  20. Forward Modeling Transient Brightenings and Microflares around an Active Region Observed with Hi-C

    NASA Astrophysics Data System (ADS)

    Kobelski, Adam R.; McKenzie, David E.

    2014-10-01

    Small-scale flare-like brightenings around active regions are among the smallest and most fundamental of energetic transient events in the corona, providing a testbed for models of heating and active region dynamics. In a previous study, we modeled a large collection of these microflares observed with Hinode/X-Ray Telescope (XRT) using EBTEL and found that they required multiple heating events, but could not distinguish between multiple heating events on a single strand, or multiple strands each experiencing a single heating event. We present here a similar study, but with extreme-ultraviolet data of Active Region 11520 from the High Resolution Coronal Imager (Hi-C) sounding rocket. Hi-C provides an order of magnitude improvement to the spatial resolution of XRT, and a cooler temperature sensitivity, which combine to provide significant improvements to our ability to detect and model microflare activity around active regions. We have found that at the spatial resolution of Hi-C (≈0.''3), the events occur much more frequently than expected (57 events detected, only 1 or 2 expected), and are most likely made from strands of the order of 100 km wide, each of which is impulsively heated with multiple heating events. These findings tend to support bursty reconnection as the cause of the energy release responsible for the brightenings.